xref: /freebsd/sys/netinet/tcp_stacks/rack.c (revision b3d14eaccc5f606690d99b1998bfdf32a22404f6) 
1 /*-
2  * Copyright (c) 2016-2020 Netflix, Inc.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  *
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include "opt_inet.h"
31 #include "opt_inet6.h"
32 #include "opt_ipsec.h"
33 #include "opt_tcpdebug.h"
34 #include "opt_ratelimit.h"
35 #include "opt_kern_tls.h"
36 #include <sys/param.h>
37 #include <sys/arb.h>
38 #include <sys/module.h>
39 #include <sys/kernel.h>
40 #ifdef TCP_HHOOK
41 #include <sys/hhook.h>
42 #endif
43 #include <sys/lock.h>
44 #include <sys/malloc.h>
45 #include <sys/lock.h>
46 #include <sys/mutex.h>
47 #include <sys/mbuf.h>
48 #include <sys/proc.h>		/* for proc0 declaration */
49 #include <sys/socket.h>
50 #include <sys/socketvar.h>
51 #include <sys/sysctl.h>
52 #include <sys/systm.h>
53 #ifdef STATS
54 #include <sys/qmath.h>
55 #include <sys/tree.h>
56 #include <sys/stats.h> /* Must come after qmath.h and tree.h */
57 #else
58 #include <sys/tree.h>
59 #endif
60 #include <sys/refcount.h>
61 #include <sys/queue.h>
62 #include <sys/tim_filter.h>
63 #include <sys/smp.h>
64 #include <sys/kthread.h>
65 #include <sys/kern_prefetch.h>
66 #include <sys/protosw.h>
67 #ifdef TCP_ACCOUNTING
68 #include <sys/sched.h>
69 #include <machine/cpu.h>
70 #endif
71 #include <vm/uma.h>
72 
73 #include <net/route.h>
74 #include <net/route/nhop.h>
75 #include <net/vnet.h>
76 
77 #define TCPSTATES		/* for logging */
78 
79 #include <netinet/in.h>
80 #include <netinet/in_kdtrace.h>
81 #include <netinet/in_pcb.h>
82 #include <netinet/ip.h>
83 #include <netinet/ip_icmp.h>	/* required for icmp_var.h */
84 #include <netinet/icmp_var.h>	/* for ICMP_BANDLIM */
85 #include <netinet/ip_var.h>
86 #include <netinet/ip6.h>
87 #include <netinet6/in6_pcb.h>
88 #include <netinet6/ip6_var.h>
89 #include <netinet/tcp.h>
90 #define	TCPOUTFLAGS
91 #include <netinet/tcp_fsm.h>
92 #include <netinet/tcp_log_buf.h>
93 #include <netinet/tcp_seq.h>
94 #include <netinet/tcp_timer.h>
95 #include <netinet/tcp_var.h>
96 #include <netinet/tcp_hpts.h>
97 #include <netinet/tcp_ratelimit.h>
98 #include <netinet/tcp_accounting.h>
99 #include <netinet/tcpip.h>
100 #include <netinet/cc/cc.h>
101 #include <netinet/cc/cc_newreno.h>
102 #include <netinet/tcp_fastopen.h>
103 #include <netinet/tcp_lro.h>
104 #ifdef NETFLIX_SHARED_CWND
105 #include <netinet/tcp_shared_cwnd.h>
106 #endif
107 #ifdef TCPDEBUG
108 #include <netinet/tcp_debug.h>
109 #endif				/* TCPDEBUG */
110 #ifdef TCP_OFFLOAD
111 #include <netinet/tcp_offload.h>
112 #endif
113 #ifdef INET6
114 #include <netinet6/tcp6_var.h>
115 #endif
116 
117 #include <netipsec/ipsec_support.h>
118 
119 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
120 #include <netipsec/ipsec.h>
121 #include <netipsec/ipsec6.h>
122 #endif				/* IPSEC */
123 
124 #include <netinet/udp.h>
125 #include <netinet/udp_var.h>
126 #include <machine/in_cksum.h>
127 
128 #ifdef MAC
129 #include <security/mac/mac_framework.h>
130 #endif
131 #include "sack_filter.h"
132 #include "tcp_rack.h"
133 #include "rack_bbr_common.h"
134 
135 uma_zone_t rack_zone;
136 uma_zone_t rack_pcb_zone;
137 
138 #ifndef TICKS2SBT
139 #define	TICKS2SBT(__t)	(tick_sbt * ((sbintime_t)(__t)))
140 #endif
141 
142 VNET_DECLARE(uint32_t, newreno_beta);
143 VNET_DECLARE(uint32_t, newreno_beta_ecn);
144 #define V_newreno_beta VNET(newreno_beta)
145 #define V_newreno_beta_ecn VNET(newreno_beta_ecn)
146 
147 
148 MALLOC_DEFINE(M_TCPFSB, "tcp_fsb", "TCP fast send block");
149 MALLOC_DEFINE(M_TCPDO, "tcp_do", "TCP deferred options");
150 
151 struct sysctl_ctx_list rack_sysctl_ctx;
152 struct sysctl_oid *rack_sysctl_root;
153 
154 #define CUM_ACKED 1
155 #define SACKED 2
156 
157 /*
158  * The RACK module incorporates a number of
159  * TCP ideas that have been put out into the IETF
160  * over the last few years:
161  * - Matt Mathis's Rate Halving which slowly drops
162  *    the congestion window so that the ack clock can
163  *    be maintained during a recovery.
164  * - Yuchung Cheng's RACK TCP (for which its named) that
165  *    will stop us using the number of dup acks and instead
166  *    use time as the gage of when we retransmit.
167  * - Reorder Detection of RFC4737 and the Tail-Loss probe draft
168  *    of Dukkipati et.al.
169  * RACK depends on SACK, so if an endpoint arrives that
170  * cannot do SACK the state machine below will shuttle the
171  * connection back to using the "default" TCP stack that is
172  * in FreeBSD.
173  *
174  * To implement RACK the original TCP stack was first decomposed
175  * into a functional state machine with individual states
176  * for each of the possible TCP connection states. The do_segment
177  * functions role in life is to mandate the connection supports SACK
178  * initially and then assure that the RACK state matches the conenction
179  * state before calling the states do_segment function. Each
180  * state is simplified due to the fact that the original do_segment
181  * has been decomposed and we *know* what state we are in (no
182  * switches on the state) and all tests for SACK are gone. This
183  * greatly simplifies what each state does.
184  *
185  * TCP output is also over-written with a new version since it
186  * must maintain the new rack scoreboard.
187  *
188  */
189 static int32_t rack_tlp_thresh = 1;
190 static int32_t rack_tlp_limit = 2;	/* No more than 2 TLPs w-out new data */
191 static int32_t rack_tlp_use_greater = 1;
192 static int32_t rack_reorder_thresh = 2;
193 static int32_t rack_reorder_fade = 60000000;	/* 0 - never fade, def 60,000,000
194 						 * - 60 seconds */
195 static uint8_t rack_req_measurements = 1;
196 /* Attack threshold detections */
197 static uint32_t rack_highest_sack_thresh_seen = 0;
198 static uint32_t rack_highest_move_thresh_seen = 0;
199 static int32_t rack_enable_hw_pacing = 0; /* Due to CCSP keep it off by default */
200 static int32_t rack_hw_pace_extra_slots = 2;	/* 2 extra MSS time betweens */
201 static int32_t rack_hw_rate_caps = 1; /* 1; */
202 static int32_t rack_hw_rate_min = 0; /* 1500000;*/
203 static int32_t rack_hw_rate_to_low = 0; /* 1200000; */
204 static int32_t rack_hw_up_only = 1;
205 static int32_t rack_stats_gets_ms_rtt = 1;
206 static int32_t rack_prr_addbackmax = 2;
207 static int32_t rack_do_hystart = 0;
208 static int32_t rack_apply_rtt_with_reduced_conf = 0;
209 
210 static int32_t rack_pkt_delay = 1000;
211 static int32_t rack_send_a_lot_in_prr = 1;
212 static int32_t rack_min_to = 1000;	/* Number of microsecond  min timeout */
213 static int32_t rack_verbose_logging = 0;
214 static int32_t rack_ignore_data_after_close = 1;
215 static int32_t rack_enable_shared_cwnd = 1;
216 static int32_t rack_use_cmp_acks = 1;
217 static int32_t rack_use_fsb = 1;
218 static int32_t rack_use_rfo = 1;
219 static int32_t rack_use_rsm_rfo = 1;
220 static int32_t rack_max_abc_post_recovery = 2;
221 static int32_t rack_client_low_buf = 0;
222 static int32_t rack_dsack_std_based = 0x3;	/* bit field bit 1 sets rc_rack_tmr_std_based and bit 2 sets rc_rack_use_dsack */
223 #ifdef TCP_ACCOUNTING
224 static int32_t rack_tcp_accounting = 0;
225 #endif
226 static int32_t rack_limits_scwnd = 1;
227 static int32_t rack_enable_mqueue_for_nonpaced = 0;
228 static int32_t rack_disable_prr = 0;
229 static int32_t use_rack_rr = 1;
230 static int32_t rack_non_rxt_use_cr = 0; /* does a non-rxt in recovery use the configured rate (ss/ca)? */
231 static int32_t rack_persist_min = 250000;	/* 250usec */
232 static int32_t rack_persist_max = 2000000;	/* 2 Second in usec's */
233 static int32_t rack_sack_not_required = 1;	/* set to one to allow non-sack to use rack */
234 static int32_t rack_default_init_window = 0;	/* Use system default */
235 static int32_t rack_limit_time_with_srtt = 0;
236 static int32_t rack_autosndbuf_inc = 20;	/* In percentage form */
237 static int32_t rack_enobuf_hw_boost_mult = 2;	/* How many times the hw rate we boost slot using time_between */
238 static int32_t rack_enobuf_hw_max = 12000;	/* 12 ms in usecs */
239 static int32_t rack_enobuf_hw_min = 10000;	/* 10 ms in usecs */
240 static int32_t rack_hw_rwnd_factor = 2;		/* How many max_segs the rwnd must be before we hold off sending */
241 /*
242  * Currently regular tcp has a rto_min of 30ms
243  * the backoff goes 12 times so that ends up
244  * being a total of 122.850 seconds before a
245  * connection is killed.
246  */
247 static uint32_t rack_def_data_window = 20;
248 static uint32_t rack_goal_bdp = 2;
249 static uint32_t rack_min_srtts = 1;
250 static uint32_t rack_min_measure_usec = 0;
251 static int32_t rack_tlp_min = 10000;	/* 10ms */
252 static int32_t rack_rto_min = 30000;	/* 30,000 usec same as main freebsd */
253 static int32_t rack_rto_max = 4000000;	/* 4 seconds in usec's */
254 static const int32_t rack_free_cache = 2;
255 static int32_t rack_hptsi_segments = 40;
256 static int32_t rack_rate_sample_method = USE_RTT_LOW;
257 static int32_t rack_pace_every_seg = 0;
258 static int32_t rack_delayed_ack_time = 40000;	/* 40ms in usecs */
259 static int32_t rack_slot_reduction = 4;
260 static int32_t rack_wma_divisor = 8;		/* For WMA calculation */
261 static int32_t rack_cwnd_block_ends_measure = 0;
262 static int32_t rack_rwnd_block_ends_measure = 0;
263 static int32_t rack_def_profile = 0;
264 
265 static int32_t rack_lower_cwnd_at_tlp = 0;
266 static int32_t rack_limited_retran = 0;
267 static int32_t rack_always_send_oldest = 0;
268 static int32_t rack_tlp_threshold_use = TLP_USE_TWO_ONE;
269 
270 static uint16_t rack_per_of_gp_ss = 250;	/* 250 % slow-start */
271 static uint16_t rack_per_of_gp_ca = 200;	/* 200 % congestion-avoidance */
272 static uint16_t rack_per_of_gp_rec = 200;	/* 200 % of bw */
273 
274 /* Probertt */
275 static uint16_t rack_per_of_gp_probertt = 60;	/* 60% of bw */
276 static uint16_t rack_per_of_gp_lowthresh = 40;	/* 40% is bottom */
277 static uint16_t rack_per_of_gp_probertt_reduce = 10; /* 10% reduction */
278 static uint16_t rack_atexit_prtt_hbp = 130;	/* Clamp to 130% on exit prtt if highly buffered path */
279 static uint16_t rack_atexit_prtt = 130;	/* Clamp to 100% on exit prtt if non highly buffered path */
280 
281 static uint32_t rack_max_drain_wait = 2;	/* How man gp srtt's before we give up draining */
282 static uint32_t rack_must_drain = 1;		/* How many GP srtt's we *must* wait */
283 static uint32_t rack_probertt_use_min_rtt_entry = 1;	/* Use the min to calculate the goal else gp_srtt */
284 static uint32_t rack_probertt_use_min_rtt_exit = 0;
285 static uint32_t rack_probe_rtt_sets_cwnd = 0;
286 static uint32_t rack_probe_rtt_safety_val = 2000000;	/* No more than 2 sec in probe-rtt */
287 static uint32_t rack_time_between_probertt = 9600000;	/* 9.6 sec in usecs */
288 static uint32_t rack_probertt_gpsrtt_cnt_mul = 0;	/* How many srtt periods does probe-rtt last top fraction */
289 static uint32_t rack_probertt_gpsrtt_cnt_div = 0;	/* How many srtt periods does probe-rtt last bottom fraction */
290 static uint32_t rack_min_probertt_hold = 40000;		/* Equal to delayed ack time */
291 static uint32_t rack_probertt_filter_life = 10000000;
292 static uint32_t rack_probertt_lower_within = 10;
293 static uint32_t rack_min_rtt_movement = 250000;	/* Must move at least 250ms (in microseconds)  to count as a lowering */
294 static int32_t rack_pace_one_seg = 0;		/* Shall we pace for less than 1.4Meg 1MSS at a time */
295 static int32_t rack_probertt_clear_is = 1;
296 static int32_t rack_max_drain_hbp = 1;		/* Extra drain times gpsrtt for highly buffered paths */
297 static int32_t rack_hbp_thresh = 3;		/* what is the divisor max_rtt/min_rtt to decided a hbp */
298 
299 /* Part of pacing */
300 static int32_t rack_max_per_above = 30;		/* When we go to increment stop if above 100+this% */
301 
302 /* Timely information */
303 /* Combine these two gives the range of 'no change' to bw */
304 /* ie the up/down provide the upper and lower bound */
305 static int32_t rack_gp_per_bw_mul_up = 2;	/* 2% */
306 static int32_t rack_gp_per_bw_mul_down = 4;	/* 4% */
307 static int32_t rack_gp_rtt_maxmul = 3;		/* 3 x maxmin */
308 static int32_t rack_gp_rtt_minmul = 1;		/* minrtt + (minrtt/mindiv) is lower rtt */
309 static int32_t rack_gp_rtt_mindiv = 4;		/* minrtt + (minrtt * minmul/mindiv) is lower rtt */
310 static int32_t rack_gp_decrease_per = 20;	/* 20% decrease in multipler */
311 static int32_t rack_gp_increase_per = 2;	/* 2% increase in multipler */
312 static int32_t rack_per_lower_bound = 50;	/* Don't allow to drop below this multiplier */
313 static int32_t rack_per_upper_bound_ss = 0;	/* Don't allow SS to grow above this */
314 static int32_t rack_per_upper_bound_ca = 0;	/* Don't allow CA to grow above this */
315 static int32_t rack_do_dyn_mul = 0;		/* Are the rack gp multipliers dynamic */
316 static int32_t rack_gp_no_rec_chg = 1;		/* Prohibit recovery from reducing it's multiplier */
317 static int32_t rack_timely_dec_clear = 6;	/* Do we clear decrement count at a value (6)? */
318 static int32_t rack_timely_max_push_rise = 3;	/* One round of pushing */
319 static int32_t rack_timely_max_push_drop = 3;	/* Three round of pushing */
320 static int32_t rack_timely_min_segs = 4;	/* 4 segment minimum */
321 static int32_t rack_use_max_for_nobackoff = 0;
322 static int32_t rack_timely_int_timely_only = 0;	/* do interim timely's only use the timely algo (no b/w changes)? */
323 static int32_t rack_timely_no_stopping = 0;
324 static int32_t rack_down_raise_thresh = 100;
325 static int32_t rack_req_segs = 1;
326 static uint64_t rack_bw_rate_cap = 0;
327 
328 /* Weird delayed ack mode */
329 static int32_t rack_use_imac_dack = 0;
330 /* Rack specific counters */
331 counter_u64_t rack_badfr;
332 counter_u64_t rack_badfr_bytes;
333 counter_u64_t rack_rtm_prr_retran;
334 counter_u64_t rack_rtm_prr_newdata;
335 counter_u64_t rack_timestamp_mismatch;
336 counter_u64_t rack_reorder_seen;
337 counter_u64_t rack_paced_segments;
338 counter_u64_t rack_unpaced_segments;
339 counter_u64_t rack_calc_zero;
340 counter_u64_t rack_calc_nonzero;
341 counter_u64_t rack_saw_enobuf;
342 counter_u64_t rack_saw_enobuf_hw;
343 counter_u64_t rack_saw_enetunreach;
344 counter_u64_t rack_per_timer_hole;
345 counter_u64_t rack_large_ackcmp;
346 counter_u64_t rack_small_ackcmp;
347 counter_u64_t rack_persists_sends;
348 counter_u64_t rack_persists_acks;
349 counter_u64_t rack_persists_loss;
350 counter_u64_t rack_persists_lost_ends;
351 #ifdef INVARIANTS
352 counter_u64_t rack_adjust_map_bw;
353 #endif
354 /* Tail loss probe counters */
355 counter_u64_t rack_tlp_tot;
356 counter_u64_t rack_tlp_newdata;
357 counter_u64_t rack_tlp_retran;
358 counter_u64_t rack_tlp_retran_bytes;
359 counter_u64_t rack_tlp_retran_fail;
360 counter_u64_t rack_to_tot;
361 counter_u64_t rack_to_arm_rack;
362 counter_u64_t rack_to_arm_tlp;
363 counter_u64_t rack_hot_alloc;
364 counter_u64_t rack_to_alloc;
365 counter_u64_t rack_to_alloc_hard;
366 counter_u64_t rack_to_alloc_emerg;
367 counter_u64_t rack_to_alloc_limited;
368 counter_u64_t rack_alloc_limited_conns;
369 counter_u64_t rack_split_limited;
370 
371 #define MAX_NUM_OF_CNTS 13
372 counter_u64_t rack_proc_comp_ack[MAX_NUM_OF_CNTS];
373 counter_u64_t rack_multi_single_eq;
374 counter_u64_t rack_proc_non_comp_ack;
375 
376 counter_u64_t rack_fto_send;
377 counter_u64_t rack_fto_rsm_send;
378 counter_u64_t rack_nfto_resend;
379 counter_u64_t rack_non_fto_send;
380 counter_u64_t rack_extended_rfo;
381 
382 counter_u64_t rack_sack_proc_all;
383 counter_u64_t rack_sack_proc_short;
384 counter_u64_t rack_sack_proc_restart;
385 counter_u64_t rack_sack_attacks_detected;
386 counter_u64_t rack_sack_attacks_reversed;
387 counter_u64_t rack_sack_used_next_merge;
388 counter_u64_t rack_sack_splits;
389 counter_u64_t rack_sack_used_prev_merge;
390 counter_u64_t rack_sack_skipped_acked;
391 counter_u64_t rack_ack_total;
392 counter_u64_t rack_express_sack;
393 counter_u64_t rack_sack_total;
394 counter_u64_t rack_move_none;
395 counter_u64_t rack_move_some;
396 
397 counter_u64_t rack_used_tlpmethod;
398 counter_u64_t rack_used_tlpmethod2;
399 counter_u64_t rack_enter_tlp_calc;
400 counter_u64_t rack_input_idle_reduces;
401 counter_u64_t rack_collapsed_win;
402 counter_u64_t rack_tlp_does_nada;
403 counter_u64_t rack_try_scwnd;
404 counter_u64_t rack_hw_pace_init_fail;
405 counter_u64_t rack_hw_pace_lost;
406 counter_u64_t rack_sbsndptr_right;
407 counter_u64_t rack_sbsndptr_wrong;
408 
409 /* Temp CPU counters */
410 counter_u64_t rack_find_high;
411 
412 counter_u64_t rack_progress_drops;
413 counter_u64_t rack_out_size[TCP_MSS_ACCT_SIZE];
414 counter_u64_t rack_opts_arry[RACK_OPTS_SIZE];
415 
416 
417 #define	RACK_REXMTVAL(tp) max(rack_rto_min, ((tp)->t_srtt + ((tp)->t_rttvar << 2)))
418 
419 #define	RACK_TCPT_RANGESET(tv, value, tvmin, tvmax, slop) do {	\
420 	(tv) = (value) + slop;	 \
421 	if ((u_long)(tv) < (u_long)(tvmin)) \
422 		(tv) = (tvmin); \
423 	if ((u_long)(tv) > (u_long)(tvmax)) \
424 		(tv) = (tvmax); \
425 } while (0)
426 
427 static void
428 rack_log_progress_event(struct tcp_rack *rack, struct tcpcb *tp, uint32_t tick,  int event, int line);
429 
430 static int
431 rack_process_ack(struct mbuf *m, struct tcphdr *th,
432     struct socket *so, struct tcpcb *tp, struct tcpopt *to,
433     uint32_t tiwin, int32_t tlen, int32_t * ofia, int32_t thflags, int32_t * ret_val);
434 static int
435 rack_process_data(struct mbuf *m, struct tcphdr *th,
436     struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
437     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt);
438 static void
439 rack_ack_received(struct tcpcb *tp, struct tcp_rack *rack,
440    uint32_t th_ack, uint16_t nsegs, uint16_t type, int32_t recovery);
441 static struct rack_sendmap *rack_alloc(struct tcp_rack *rack);
442 static struct rack_sendmap *rack_alloc_limit(struct tcp_rack *rack,
443     uint8_t limit_type);
444 static struct rack_sendmap *
445 rack_check_recovery_mode(struct tcpcb *tp,
446     uint32_t tsused);
447 static void
448 rack_cong_signal(struct tcpcb *tp,
449 		 uint32_t type, uint32_t ack);
450 static void rack_counter_destroy(void);
451 static int
452 rack_ctloutput(struct socket *so, struct sockopt *sopt,
453     struct inpcb *inp, struct tcpcb *tp);
454 static int32_t rack_ctor(void *mem, int32_t size, void *arg, int32_t how);
455 static void
456 rack_set_pace_segments(struct tcpcb *tp, struct tcp_rack *rack, uint32_t line, uint64_t *fill_override);
457 static void
458 rack_do_segment(struct mbuf *m, struct tcphdr *th,
459     struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
460     uint8_t iptos);
461 static void rack_dtor(void *mem, int32_t size, void *arg);
462 static void
463 rack_log_alt_to_to_cancel(struct tcp_rack *rack,
464     uint32_t flex1, uint32_t flex2,
465     uint32_t flex3, uint32_t flex4,
466     uint32_t flex5, uint32_t flex6,
467     uint16_t flex7, uint8_t mod);
468 
469 static void
470 rack_log_pacing_delay_calc(struct tcp_rack *rack, uint32_t len, uint32_t slot,
471    uint64_t bw_est, uint64_t bw, uint64_t len_time, int method, int line,
472    struct rack_sendmap *rsm, uint8_t quality);
473 static struct rack_sendmap *
474 rack_find_high_nonack(struct tcp_rack *rack,
475     struct rack_sendmap *rsm);
476 static struct rack_sendmap *rack_find_lowest_rsm(struct tcp_rack *rack);
477 static void rack_free(struct tcp_rack *rack, struct rack_sendmap *rsm);
478 static void rack_fini(struct tcpcb *tp, int32_t tcb_is_purged);
479 static int
480 rack_get_sockopt(struct socket *so, struct sockopt *sopt,
481     struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack);
482 static void
483 rack_do_goodput_measurement(struct tcpcb *tp, struct tcp_rack *rack,
484 			    tcp_seq th_ack, int line, uint8_t quality);
485 static uint32_t
486 rack_get_pacing_len(struct tcp_rack *rack, uint64_t bw, uint32_t mss);
487 static int32_t rack_handoff_ok(struct tcpcb *tp);
488 static int32_t rack_init(struct tcpcb *tp);
489 static void rack_init_sysctls(void);
490 static void
491 rack_log_ack(struct tcpcb *tp, struct tcpopt *to,
492     struct tcphdr *th, int entered_rec, int dup_ack_struck);
493 static void
494 rack_log_output(struct tcpcb *tp, struct tcpopt *to, int32_t len,
495     uint32_t seq_out, uint8_t th_flags, int32_t err, uint64_t ts,
496     struct rack_sendmap *hintrsm, uint16_t add_flags, struct mbuf *s_mb, uint32_t s_moff, int hw_tls);
497 
498 static void
499 rack_log_sack_passed(struct tcpcb *tp, struct tcp_rack *rack,
500     struct rack_sendmap *rsm);
501 static void rack_log_to_event(struct tcp_rack *rack, int32_t to_num, struct rack_sendmap *rsm);
502 static int32_t rack_output(struct tcpcb *tp);
503 
504 static uint32_t
505 rack_proc_sack_blk(struct tcpcb *tp, struct tcp_rack *rack,
506     struct sackblk *sack, struct tcpopt *to, struct rack_sendmap **prsm,
507     uint32_t cts, int *moved_two);
508 static void rack_post_recovery(struct tcpcb *tp, uint32_t th_seq);
509 static void rack_remxt_tmr(struct tcpcb *tp);
510 static int
511 rack_set_sockopt(struct socket *so, struct sockopt *sopt,
512     struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack);
513 static void rack_set_state(struct tcpcb *tp, struct tcp_rack *rack);
514 static int32_t rack_stopall(struct tcpcb *tp);
515 static void
516 rack_timer_activate(struct tcpcb *tp, uint32_t timer_type,
517     uint32_t delta);
518 static int32_t rack_timer_active(struct tcpcb *tp, uint32_t timer_type);
519 static void rack_timer_cancel(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int line);
520 static void rack_timer_stop(struct tcpcb *tp, uint32_t timer_type);
521 static uint32_t
522 rack_update_entry(struct tcpcb *tp, struct tcp_rack *rack,
523     struct rack_sendmap *rsm, uint64_t ts, int32_t * lenp, uint16_t add_flag);
524 static void
525 rack_update_rsm(struct tcpcb *tp, struct tcp_rack *rack,
526     struct rack_sendmap *rsm, uint64_t ts, uint16_t add_flag);
527 static int
528 rack_update_rtt(struct tcpcb *tp, struct tcp_rack *rack,
529     struct rack_sendmap *rsm, struct tcpopt *to, uint32_t cts, int32_t ack_type, tcp_seq th_ack);
530 static int32_t tcp_addrack(module_t mod, int32_t type, void *data);
531 static int
532 rack_do_close_wait(struct mbuf *m, struct tcphdr *th,
533     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
534     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
535 static int
536 rack_do_closing(struct mbuf *m, struct tcphdr *th,
537     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
538     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
539 static int
540 rack_do_established(struct mbuf *m, struct tcphdr *th,
541     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
542     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
543 static int
544 rack_do_fastnewdata(struct mbuf *m, struct tcphdr *th,
545     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
546     int32_t tlen, uint32_t tiwin, int32_t nxt_pkt, uint8_t iptos);
547 static int
548 rack_do_fin_wait_1(struct mbuf *m, struct tcphdr *th,
549     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
550     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
551 static int
552 rack_do_fin_wait_2(struct mbuf *m, struct tcphdr *th,
553     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
554     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
555 static int
556 rack_do_lastack(struct mbuf *m, struct tcphdr *th,
557     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
558     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
559 static int
560 rack_do_syn_recv(struct mbuf *m, struct tcphdr *th,
561     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
562     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
563 static int
564 rack_do_syn_sent(struct mbuf *m, struct tcphdr *th,
565     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
566     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
567 struct rack_sendmap *
568 tcp_rack_output(struct tcpcb *tp, struct tcp_rack *rack,
569     uint32_t tsused);
570 static void tcp_rack_xmit_timer(struct tcp_rack *rack, int32_t rtt,
571     uint32_t len, uint32_t us_tim, int confidence, struct rack_sendmap *rsm, uint16_t rtrcnt);
572 static void
573      tcp_rack_partialack(struct tcpcb *tp);
574 static int
575 rack_set_profile(struct tcp_rack *rack, int prof);
576 static void
577 rack_apply_deferred_options(struct tcp_rack *rack);
578 
579 int32_t rack_clear_counter=0;
580 
581 static void
582 rack_set_cc_pacing(struct tcp_rack *rack)
583 {
584 	struct sockopt sopt;
585 	struct cc_newreno_opts opt;
586 	struct newreno old, *ptr;
587 	struct tcpcb *tp;
588 	int error;
589 
590 	if (rack->rc_pacing_cc_set)
591 		return;
592 
593 	tp = rack->rc_tp;
594 	if (tp->cc_algo == NULL) {
595 		/* Tcb is leaving */
596 		printf("No cc algorithm?\n");
597 		return;
598 	}
599 	rack->rc_pacing_cc_set = 1;
600 	if (strcmp(tp->cc_algo->name, CCALGONAME_NEWRENO) != 0) {
601 		/* Not new-reno we can't play games with beta! */
602 		goto out;
603 	}
604 	ptr = ((struct newreno *)tp->ccv->cc_data);
605 	if (CC_ALGO(tp)->ctl_output == NULL)  {
606 		/* Huh, why does new_reno no longer have a set function? */
607 		goto out;
608 	}
609 	if (ptr == NULL) {
610 		/* Just the default values */
611 		old.beta = V_newreno_beta_ecn;
612 		old.beta_ecn = V_newreno_beta_ecn;
613 		old.newreno_flags = 0;
614 	} else {
615 		old.beta = ptr->beta;
616 		old.beta_ecn = ptr->beta_ecn;
617 		old.newreno_flags = ptr->newreno_flags;
618 	}
619 	sopt.sopt_valsize = sizeof(struct cc_newreno_opts);
620 	sopt.sopt_dir = SOPT_SET;
621 	opt.name = CC_NEWRENO_BETA;
622 	opt.val = rack->r_ctl.rc_saved_beta.beta;
623 	error = CC_ALGO(tp)->ctl_output(tp->ccv, &sopt, &opt);
624 	if (error)  {
625 		goto out;
626 	}
627 	/*
628 	 * Hack alert we need to set in our newreno_flags
629 	 * so that Abe behavior is also applied.
630 	 */
631 	((struct newreno *)tp->ccv->cc_data)->newreno_flags |= CC_NEWRENO_BETA_ECN_ENABLED;
632 	opt.name = CC_NEWRENO_BETA_ECN;
633 	opt.val = rack->r_ctl.rc_saved_beta.beta_ecn;
634 	error = CC_ALGO(tp)->ctl_output(tp->ccv, &sopt, &opt);
635 	if (error) {
636 		goto out;
637 	}
638 	/* Save off the original values for restoral */
639 	memcpy(&rack->r_ctl.rc_saved_beta, &old, sizeof(struct newreno));
640 out:
641 	if (rack_verbose_logging && (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
642 		union tcp_log_stackspecific log;
643 		struct timeval tv;
644 
645 		ptr = ((struct newreno *)tp->ccv->cc_data);
646 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
647 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
648 		if (ptr) {
649 			log.u_bbr.flex1 = ptr->beta;
650 			log.u_bbr.flex2 = ptr->beta_ecn;
651 			log.u_bbr.flex3 = ptr->newreno_flags;
652 		}
653 		log.u_bbr.flex4 = rack->r_ctl.rc_saved_beta.beta;
654 		log.u_bbr.flex5 = rack->r_ctl.rc_saved_beta.beta_ecn;
655 		log.u_bbr.flex6 = rack->r_ctl.rc_saved_beta.newreno_flags;
656 		log.u_bbr.flex7 = rack->gp_ready;
657 		log.u_bbr.flex7 <<= 1;
658 		log.u_bbr.flex7 |= rack->use_fixed_rate;
659 		log.u_bbr.flex7 <<= 1;
660 		log.u_bbr.flex7 |= rack->rc_pacing_cc_set;
661 		log.u_bbr.pkts_out = rack->r_ctl.rc_prr_sndcnt;
662 		log.u_bbr.flex8 = 3;
663 		tcp_log_event_(tp, NULL, NULL, NULL, BBR_LOG_CWND, error,
664 			       0, &log, false, NULL, NULL, 0, &tv);
665 	}
666 }
667 
668 static void
669 rack_undo_cc_pacing(struct tcp_rack *rack)
670 {
671 	struct newreno old, *ptr;
672 	struct tcpcb *tp;
673 
674 	if (rack->rc_pacing_cc_set == 0)
675 		return;
676 	tp = rack->rc_tp;
677 	rack->rc_pacing_cc_set = 0;
678 	if (tp->cc_algo == NULL)
679 		/* Tcb is leaving */
680 		return;
681 	if (strcmp(tp->cc_algo->name, CCALGONAME_NEWRENO) != 0) {
682 		/* Not new-reno nothing to do! */
683 		return;
684 	}
685 	ptr = ((struct newreno *)tp->ccv->cc_data);
686 	if (ptr == NULL) {
687 		/*
688 		 * This happens at rack_fini() if the
689 		 * cc module gets freed on us. In that
690 		 * case we loose our "new" settings but
691 		 * thats ok, since the tcb is going away anyway.
692 		 */
693 		return;
694 	}
695 	/* Grab out our set values */
696 	memcpy(&old, ptr, sizeof(struct newreno));
697 	/* Copy back in the original values */
698 	memcpy(ptr, &rack->r_ctl.rc_saved_beta, sizeof(struct newreno));
699 	/* Now save back the values we had set in (for when pacing is restored) */
700 	memcpy(&rack->r_ctl.rc_saved_beta, &old, sizeof(struct newreno));
701 	if (rack_verbose_logging && (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
702 		union tcp_log_stackspecific log;
703 		struct timeval tv;
704 
705 		ptr = ((struct newreno *)tp->ccv->cc_data);
706 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
707 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
708 		log.u_bbr.flex1 = ptr->beta;
709 		log.u_bbr.flex2 = ptr->beta_ecn;
710 		log.u_bbr.flex3 = ptr->newreno_flags;
711 		log.u_bbr.flex4 = rack->r_ctl.rc_saved_beta.beta;
712 		log.u_bbr.flex5 = rack->r_ctl.rc_saved_beta.beta_ecn;
713 		log.u_bbr.flex6 = rack->r_ctl.rc_saved_beta.newreno_flags;
714 		log.u_bbr.flex7 = rack->gp_ready;
715 		log.u_bbr.flex7 <<= 1;
716 		log.u_bbr.flex7 |= rack->use_fixed_rate;
717 		log.u_bbr.flex7 <<= 1;
718 		log.u_bbr.flex7 |= rack->rc_pacing_cc_set;
719 		log.u_bbr.pkts_out = rack->r_ctl.rc_prr_sndcnt;
720 		log.u_bbr.flex8 = 4;
721 		tcp_log_event_(tp, NULL, NULL, NULL, BBR_LOG_CWND, 0,
722 			       0, &log, false, NULL, NULL, 0, &tv);
723 	}
724 }
725 
726 #ifdef NETFLIX_PEAKRATE
727 static inline void
728 rack_update_peakrate_thr(struct tcpcb *tp)
729 {
730 	/* Keep in mind that t_maxpeakrate is in B/s. */
731 	uint64_t peak;
732 	peak = uqmax((tp->t_maxseg * 2),
733 		     (((uint64_t)tp->t_maxpeakrate * (uint64_t)(tp->t_srtt)) / (uint64_t)HPTS_USEC_IN_SEC));
734 	tp->t_peakrate_thr = (uint32_t)uqmin(peak, UINT32_MAX);
735 }
736 #endif
737 
738 static int
739 sysctl_rack_clear(SYSCTL_HANDLER_ARGS)
740 {
741 	uint32_t stat;
742 	int32_t error;
743 	int i;
744 
745 	error = SYSCTL_OUT(req, &rack_clear_counter, sizeof(uint32_t));
746 	if (error || req->newptr == NULL)
747 		return error;
748 
749 	error = SYSCTL_IN(req, &stat, sizeof(uint32_t));
750 	if (error)
751 		return (error);
752 	if (stat == 1) {
753 #ifdef INVARIANTS
754 		printf("Clearing RACK counters\n");
755 #endif
756 		counter_u64_zero(rack_badfr);
757 		counter_u64_zero(rack_badfr_bytes);
758 		counter_u64_zero(rack_rtm_prr_retran);
759 		counter_u64_zero(rack_rtm_prr_newdata);
760 		counter_u64_zero(rack_timestamp_mismatch);
761 		counter_u64_zero(rack_reorder_seen);
762 		counter_u64_zero(rack_tlp_tot);
763 		counter_u64_zero(rack_tlp_newdata);
764 		counter_u64_zero(rack_tlp_retran);
765 		counter_u64_zero(rack_tlp_retran_bytes);
766 		counter_u64_zero(rack_tlp_retran_fail);
767 		counter_u64_zero(rack_to_tot);
768 		counter_u64_zero(rack_to_arm_rack);
769 		counter_u64_zero(rack_to_arm_tlp);
770 		counter_u64_zero(rack_paced_segments);
771 		counter_u64_zero(rack_calc_zero);
772 		counter_u64_zero(rack_calc_nonzero);
773 		counter_u64_zero(rack_unpaced_segments);
774 		counter_u64_zero(rack_saw_enobuf);
775 		counter_u64_zero(rack_saw_enobuf_hw);
776 		counter_u64_zero(rack_saw_enetunreach);
777 		counter_u64_zero(rack_per_timer_hole);
778 		counter_u64_zero(rack_large_ackcmp);
779 		counter_u64_zero(rack_small_ackcmp);
780 		counter_u64_zero(rack_persists_sends);
781 		counter_u64_zero(rack_persists_acks);
782 		counter_u64_zero(rack_persists_loss);
783 		counter_u64_zero(rack_persists_lost_ends);
784 #ifdef INVARIANTS
785 		counter_u64_zero(rack_adjust_map_bw);
786 #endif
787 		counter_u64_zero(rack_to_alloc_hard);
788 		counter_u64_zero(rack_to_alloc_emerg);
789 		counter_u64_zero(rack_sack_proc_all);
790 		counter_u64_zero(rack_fto_send);
791 		counter_u64_zero(rack_fto_rsm_send);
792 		counter_u64_zero(rack_extended_rfo);
793 		counter_u64_zero(rack_hw_pace_init_fail);
794 		counter_u64_zero(rack_hw_pace_lost);
795 		counter_u64_zero(rack_sbsndptr_wrong);
796 		counter_u64_zero(rack_sbsndptr_right);
797 		counter_u64_zero(rack_non_fto_send);
798 		counter_u64_zero(rack_nfto_resend);
799 		counter_u64_zero(rack_sack_proc_short);
800 		counter_u64_zero(rack_sack_proc_restart);
801 		counter_u64_zero(rack_to_alloc);
802 		counter_u64_zero(rack_to_alloc_limited);
803 		counter_u64_zero(rack_alloc_limited_conns);
804 		counter_u64_zero(rack_split_limited);
805 		for (i = 0; i < MAX_NUM_OF_CNTS; i++) {
806 			counter_u64_zero(rack_proc_comp_ack[i]);
807 		}
808 		counter_u64_zero(rack_multi_single_eq);
809 		counter_u64_zero(rack_proc_non_comp_ack);
810 		counter_u64_zero(rack_find_high);
811 		counter_u64_zero(rack_sack_attacks_detected);
812 		counter_u64_zero(rack_sack_attacks_reversed);
813 		counter_u64_zero(rack_sack_used_next_merge);
814 		counter_u64_zero(rack_sack_used_prev_merge);
815 		counter_u64_zero(rack_sack_splits);
816 		counter_u64_zero(rack_sack_skipped_acked);
817 		counter_u64_zero(rack_ack_total);
818 		counter_u64_zero(rack_express_sack);
819 		counter_u64_zero(rack_sack_total);
820 		counter_u64_zero(rack_move_none);
821 		counter_u64_zero(rack_move_some);
822 		counter_u64_zero(rack_used_tlpmethod);
823 		counter_u64_zero(rack_used_tlpmethod2);
824 		counter_u64_zero(rack_enter_tlp_calc);
825 		counter_u64_zero(rack_progress_drops);
826 		counter_u64_zero(rack_tlp_does_nada);
827 		counter_u64_zero(rack_try_scwnd);
828 		counter_u64_zero(rack_collapsed_win);
829 	}
830 	rack_clear_counter = 0;
831 	return (0);
832 }
833 
834 static void
835 rack_init_sysctls(void)
836 {
837 	int i;
838 	struct sysctl_oid *rack_counters;
839 	struct sysctl_oid *rack_attack;
840 	struct sysctl_oid *rack_pacing;
841 	struct sysctl_oid *rack_timely;
842 	struct sysctl_oid *rack_timers;
843 	struct sysctl_oid *rack_tlp;
844 	struct sysctl_oid *rack_misc;
845 	struct sysctl_oid *rack_features;
846 	struct sysctl_oid *rack_measure;
847 	struct sysctl_oid *rack_probertt;
848 	struct sysctl_oid *rack_hw_pacing;
849 
850 	rack_attack = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
851 	    SYSCTL_CHILDREN(rack_sysctl_root),
852 	    OID_AUTO,
853 	    "sack_attack",
854 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
855 	    "Rack Sack Attack Counters and Controls");
856 	rack_counters = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
857 	    SYSCTL_CHILDREN(rack_sysctl_root),
858 	    OID_AUTO,
859 	    "stats",
860 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
861 	    "Rack Counters");
862 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
863 	    SYSCTL_CHILDREN(rack_sysctl_root),
864 	    OID_AUTO, "rate_sample_method", CTLFLAG_RW,
865 	    &rack_rate_sample_method , USE_RTT_LOW,
866 	    "What method should we use for rate sampling 0=high, 1=low ");
867 	/* Probe rtt related controls */
868 	rack_probertt = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
869 	    SYSCTL_CHILDREN(rack_sysctl_root),
870 	    OID_AUTO,
871 	    "probertt",
872 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
873 	    "ProbeRTT related Controls");
874 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
875 	    SYSCTL_CHILDREN(rack_probertt),
876 	    OID_AUTO, "exit_per_hpb", CTLFLAG_RW,
877 	    &rack_atexit_prtt_hbp, 130,
878 	    "What percentage above goodput do we clamp CA/SS to at exit on high-BDP path 110%");
879 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
880 	    SYSCTL_CHILDREN(rack_probertt),
881 	    OID_AUTO, "exit_per_nonhpb", CTLFLAG_RW,
882 	    &rack_atexit_prtt, 130,
883 	    "What percentage above goodput do we clamp CA/SS to at exit on a non high-BDP path 100%");
884 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
885 	    SYSCTL_CHILDREN(rack_probertt),
886 	    OID_AUTO, "gp_per_mul", CTLFLAG_RW,
887 	    &rack_per_of_gp_probertt, 60,
888 	    "What percentage of goodput do we pace at in probertt");
889 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
890 	    SYSCTL_CHILDREN(rack_probertt),
891 	    OID_AUTO, "gp_per_reduce", CTLFLAG_RW,
892 	    &rack_per_of_gp_probertt_reduce, 10,
893 	    "What percentage of goodput do we reduce every gp_srtt");
894 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
895 	    SYSCTL_CHILDREN(rack_probertt),
896 	    OID_AUTO, "gp_per_low", CTLFLAG_RW,
897 	    &rack_per_of_gp_lowthresh, 40,
898 	    "What percentage of goodput do we allow the multiplier to fall to");
899 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
900 	    SYSCTL_CHILDREN(rack_probertt),
901 	    OID_AUTO, "time_between", CTLFLAG_RW,
902 	    & rack_time_between_probertt, 96000000,
903 	    "How many useconds between the lowest rtt falling must past before we enter probertt");
904 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
905 	    SYSCTL_CHILDREN(rack_probertt),
906 	    OID_AUTO, "safety", CTLFLAG_RW,
907 	    &rack_probe_rtt_safety_val, 2000000,
908 	    "If not zero, provides a maximum usecond that you can stay in probertt (2sec = 2000000)");
909 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
910 	    SYSCTL_CHILDREN(rack_probertt),
911 	    OID_AUTO, "sets_cwnd", CTLFLAG_RW,
912 	    &rack_probe_rtt_sets_cwnd, 0,
913 	    "Do we set the cwnd too (if always_lower is on)");
914 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
915 	    SYSCTL_CHILDREN(rack_probertt),
916 	    OID_AUTO, "maxdrainsrtts", CTLFLAG_RW,
917 	    &rack_max_drain_wait, 2,
918 	    "Maximum number of gp_srtt's to hold in drain waiting for flight to reach goal");
919 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
920 	    SYSCTL_CHILDREN(rack_probertt),
921 	    OID_AUTO, "mustdrainsrtts", CTLFLAG_RW,
922 	    &rack_must_drain, 1,
923 	    "We must drain this many gp_srtt's waiting for flight to reach goal");
924 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
925 	    SYSCTL_CHILDREN(rack_probertt),
926 	    OID_AUTO, "goal_use_min_entry", CTLFLAG_RW,
927 	    &rack_probertt_use_min_rtt_entry, 1,
928 	    "Should we use the min-rtt to calculate the goal rtt (else gp_srtt) at entry");
929 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
930 	    SYSCTL_CHILDREN(rack_probertt),
931 	    OID_AUTO, "goal_use_min_exit", CTLFLAG_RW,
932 	    &rack_probertt_use_min_rtt_exit, 0,
933 	    "How to set cwnd at exit, 0 - dynamic, 1 - use min-rtt, 2 - use curgprtt, 3 - entry gp-rtt");
934 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
935 	    SYSCTL_CHILDREN(rack_probertt),
936 	    OID_AUTO, "length_div", CTLFLAG_RW,
937 	    &rack_probertt_gpsrtt_cnt_div, 0,
938 	    "How many recent goodput srtt periods plus hold tim does probertt last (bottom of fraction)");
939 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
940 	    SYSCTL_CHILDREN(rack_probertt),
941 	    OID_AUTO, "length_mul", CTLFLAG_RW,
942 	    &rack_probertt_gpsrtt_cnt_mul, 0,
943 	    "How many recent goodput srtt periods plus hold tim does probertt last (top of fraction)");
944 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
945 	    SYSCTL_CHILDREN(rack_probertt),
946 	    OID_AUTO, "holdtim_at_target", CTLFLAG_RW,
947 	    &rack_min_probertt_hold, 200000,
948 	    "What is the minimum time we hold probertt at target");
949 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
950 	    SYSCTL_CHILDREN(rack_probertt),
951 	    OID_AUTO, "filter_life", CTLFLAG_RW,
952 	    &rack_probertt_filter_life, 10000000,
953 	    "What is the time for the filters life in useconds");
954 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
955 	    SYSCTL_CHILDREN(rack_probertt),
956 	    OID_AUTO, "lower_within", CTLFLAG_RW,
957 	    &rack_probertt_lower_within, 10,
958 	    "If the rtt goes lower within this percentage of the time, go into probe-rtt");
959 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
960 	    SYSCTL_CHILDREN(rack_probertt),
961 	    OID_AUTO, "must_move", CTLFLAG_RW,
962 	    &rack_min_rtt_movement, 250,
963 	    "How much is the minimum movement in rtt to count as a drop for probertt purposes");
964 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
965 	    SYSCTL_CHILDREN(rack_probertt),
966 	    OID_AUTO, "clear_is_cnts", CTLFLAG_RW,
967 	    &rack_probertt_clear_is, 1,
968 	    "Do we clear I/S counts on exiting probe-rtt");
969 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
970 	    SYSCTL_CHILDREN(rack_probertt),
971 	    OID_AUTO, "hbp_extra_drain", CTLFLAG_RW,
972 	    &rack_max_drain_hbp, 1,
973 	    "How many extra drain gpsrtt's do we get in highly buffered paths");
974 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
975 	    SYSCTL_CHILDREN(rack_probertt),
976 	    OID_AUTO, "hbp_threshold", CTLFLAG_RW,
977 	    &rack_hbp_thresh, 3,
978 	    "We are highly buffered if min_rtt_seen / max_rtt_seen > this-threshold");
979 	/* Pacing related sysctls */
980 	rack_pacing = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
981 	    SYSCTL_CHILDREN(rack_sysctl_root),
982 	    OID_AUTO,
983 	    "pacing",
984 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
985 	    "Pacing related Controls");
986 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
987 	    SYSCTL_CHILDREN(rack_pacing),
988 	    OID_AUTO, "max_pace_over", CTLFLAG_RW,
989 	    &rack_max_per_above, 30,
990 	    "What is the maximum allowable percentage that we can pace above (so 30 = 130% of our goal)");
991 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
992 	    SYSCTL_CHILDREN(rack_pacing),
993 	    OID_AUTO, "pace_to_one", CTLFLAG_RW,
994 	    &rack_pace_one_seg, 0,
995 	    "Do we allow low b/w pacing of 1MSS instead of two");
996 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
997 	    SYSCTL_CHILDREN(rack_pacing),
998 	    OID_AUTO, "limit_wsrtt", CTLFLAG_RW,
999 	    &rack_limit_time_with_srtt, 0,
1000 	    "Do we limit pacing time based on srtt");
1001 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1002 	    SYSCTL_CHILDREN(rack_pacing),
1003 	    OID_AUTO, "init_win", CTLFLAG_RW,
1004 	    &rack_default_init_window, 0,
1005 	    "Do we have a rack initial window 0 = system default");
1006 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
1007 	    SYSCTL_CHILDREN(rack_pacing),
1008 	    OID_AUTO, "gp_per_ss", CTLFLAG_RW,
1009 	    &rack_per_of_gp_ss, 250,
1010 	    "If non zero, what percentage of goodput to pace at in slow start");
1011 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
1012 	    SYSCTL_CHILDREN(rack_pacing),
1013 	    OID_AUTO, "gp_per_ca", CTLFLAG_RW,
1014 	    &rack_per_of_gp_ca, 150,
1015 	    "If non zero, what percentage of goodput to pace at in congestion avoidance");
1016 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
1017 	    SYSCTL_CHILDREN(rack_pacing),
1018 	    OID_AUTO, "gp_per_rec", CTLFLAG_RW,
1019 	    &rack_per_of_gp_rec, 200,
1020 	    "If non zero, what percentage of goodput to pace at in recovery");
1021 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1022 	    SYSCTL_CHILDREN(rack_pacing),
1023 	    OID_AUTO, "pace_max_seg", CTLFLAG_RW,
1024 	    &rack_hptsi_segments, 40,
1025 	    "What size is the max for TSO segments in pacing and burst mitigation");
1026 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1027 	    SYSCTL_CHILDREN(rack_pacing),
1028 	    OID_AUTO, "burst_reduces", CTLFLAG_RW,
1029 	    &rack_slot_reduction, 4,
1030 	    "When doing only burst mitigation what is the reduce divisor");
1031 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1032 	    SYSCTL_CHILDREN(rack_sysctl_root),
1033 	    OID_AUTO, "use_pacing", CTLFLAG_RW,
1034 	    &rack_pace_every_seg, 0,
1035 	    "If set we use pacing, if clear we use only the original burst mitigation");
1036 	SYSCTL_ADD_U64(&rack_sysctl_ctx,
1037 	    SYSCTL_CHILDREN(rack_pacing),
1038 	    OID_AUTO, "rate_cap", CTLFLAG_RW,
1039 	    &rack_bw_rate_cap, 0,
1040 	    "If set we apply this value to the absolute rate cap used by pacing");
1041 	SYSCTL_ADD_U8(&rack_sysctl_ctx,
1042 	    SYSCTL_CHILDREN(rack_sysctl_root),
1043 	    OID_AUTO, "req_measure_cnt", CTLFLAG_RW,
1044 	    &rack_req_measurements, 1,
1045 	    "If doing dynamic pacing, how many measurements must be in before we start pacing?");
1046 	/* Hardware pacing */
1047 	rack_hw_pacing = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1048 	    SYSCTL_CHILDREN(rack_sysctl_root),
1049 	    OID_AUTO,
1050 	    "hdwr_pacing",
1051 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1052 	    "Pacing related Controls");
1053 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1054 	    SYSCTL_CHILDREN(rack_hw_pacing),
1055 	    OID_AUTO, "rwnd_factor", CTLFLAG_RW,
1056 	    &rack_hw_rwnd_factor, 2,
1057 	    "How many times does snd_wnd need to be bigger than pace_max_seg so we will hold off and get more acks?");
1058 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1059 	    SYSCTL_CHILDREN(rack_hw_pacing),
1060 	    OID_AUTO, "pace_enobuf_mult", CTLFLAG_RW,
1061 	    &rack_enobuf_hw_boost_mult, 2,
1062 	    "By how many time_betweens should we boost the pacing time if we see a ENOBUFS?");
1063 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1064 	    SYSCTL_CHILDREN(rack_hw_pacing),
1065 	    OID_AUTO, "pace_enobuf_max", CTLFLAG_RW,
1066 	    &rack_enobuf_hw_max, 2,
1067 	    "What is the max boost the pacing time if we see a ENOBUFS?");
1068 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1069 	    SYSCTL_CHILDREN(rack_hw_pacing),
1070 	    OID_AUTO, "pace_enobuf_min", CTLFLAG_RW,
1071 	    &rack_enobuf_hw_min, 2,
1072 	    "What is the min boost the pacing time if we see a ENOBUFS?");
1073 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1074 	    SYSCTL_CHILDREN(rack_hw_pacing),
1075 	    OID_AUTO, "enable", CTLFLAG_RW,
1076 	    &rack_enable_hw_pacing, 0,
1077 	    "Should RACK attempt to use hw pacing?");
1078 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1079 	    SYSCTL_CHILDREN(rack_hw_pacing),
1080 	    OID_AUTO, "rate_cap", CTLFLAG_RW,
1081 	    &rack_hw_rate_caps, 1,
1082 	    "Does the highest hardware pacing rate cap the rate we will send at??");
1083 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1084 	    SYSCTL_CHILDREN(rack_hw_pacing),
1085 	    OID_AUTO, "rate_min", CTLFLAG_RW,
1086 	    &rack_hw_rate_min, 0,
1087 	    "Do we need a minimum estimate of this many bytes per second in order to engage hw pacing?");
1088 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1089 	    SYSCTL_CHILDREN(rack_hw_pacing),
1090 	    OID_AUTO, "rate_to_low", CTLFLAG_RW,
1091 	    &rack_hw_rate_to_low, 0,
1092 	    "If we fall below this rate, dis-engage hw pacing?");
1093 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1094 	    SYSCTL_CHILDREN(rack_hw_pacing),
1095 	    OID_AUTO, "up_only", CTLFLAG_RW,
1096 	    &rack_hw_up_only, 1,
1097 	    "Do we allow hw pacing to lower the rate selected?");
1098 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1099 	    SYSCTL_CHILDREN(rack_hw_pacing),
1100 	    OID_AUTO, "extra_mss_precise", CTLFLAG_RW,
1101 	    &rack_hw_pace_extra_slots, 2,
1102 	    "If the rates between software and hardware match precisely how many extra time_betweens do we get?");
1103 	rack_timely = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1104 	    SYSCTL_CHILDREN(rack_sysctl_root),
1105 	    OID_AUTO,
1106 	    "timely",
1107 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1108 	    "Rack Timely RTT Controls");
1109 	/* Timely based GP dynmics */
1110 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1111 	    SYSCTL_CHILDREN(rack_timely),
1112 	    OID_AUTO, "upper", CTLFLAG_RW,
1113 	    &rack_gp_per_bw_mul_up, 2,
1114 	    "Rack timely upper range for equal b/w (in percentage)");
1115 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1116 	    SYSCTL_CHILDREN(rack_timely),
1117 	    OID_AUTO, "lower", CTLFLAG_RW,
1118 	    &rack_gp_per_bw_mul_down, 4,
1119 	    "Rack timely lower range for equal b/w (in percentage)");
1120 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1121 	    SYSCTL_CHILDREN(rack_timely),
1122 	    OID_AUTO, "rtt_max_mul", CTLFLAG_RW,
1123 	    &rack_gp_rtt_maxmul, 3,
1124 	    "Rack timely multipler of lowest rtt for rtt_max");
1125 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1126 	    SYSCTL_CHILDREN(rack_timely),
1127 	    OID_AUTO, "rtt_min_div", CTLFLAG_RW,
1128 	    &rack_gp_rtt_mindiv, 4,
1129 	    "Rack timely divisor used for rtt + (rtt * mul/divisor) for check for lower rtt");
1130 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1131 	    SYSCTL_CHILDREN(rack_timely),
1132 	    OID_AUTO, "rtt_min_mul", CTLFLAG_RW,
1133 	    &rack_gp_rtt_minmul, 1,
1134 	    "Rack timely multiplier used for rtt + (rtt * mul/divisor) for check for lower rtt");
1135 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1136 	    SYSCTL_CHILDREN(rack_timely),
1137 	    OID_AUTO, "decrease", CTLFLAG_RW,
1138 	    &rack_gp_decrease_per, 20,
1139 	    "Rack timely decrease percentage of our GP multiplication factor");
1140 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1141 	    SYSCTL_CHILDREN(rack_timely),
1142 	    OID_AUTO, "increase", CTLFLAG_RW,
1143 	    &rack_gp_increase_per, 2,
1144 	    "Rack timely increase perentage of our GP multiplication factor");
1145 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1146 	    SYSCTL_CHILDREN(rack_timely),
1147 	    OID_AUTO, "lowerbound", CTLFLAG_RW,
1148 	    &rack_per_lower_bound, 50,
1149 	    "Rack timely lowest percentage we allow GP multiplier to fall to");
1150 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1151 	    SYSCTL_CHILDREN(rack_timely),
1152 	    OID_AUTO, "upperboundss", CTLFLAG_RW,
1153 	    &rack_per_upper_bound_ss, 0,
1154 	    "Rack timely higest percentage we allow GP multiplier in SS to raise to (0 is no upperbound)");
1155 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1156 	    SYSCTL_CHILDREN(rack_timely),
1157 	    OID_AUTO, "upperboundca", CTLFLAG_RW,
1158 	    &rack_per_upper_bound_ca, 0,
1159 	    "Rack timely higest percentage we allow GP multiplier to CA raise to (0 is no upperbound)");
1160 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1161 	    SYSCTL_CHILDREN(rack_timely),
1162 	    OID_AUTO, "dynamicgp", CTLFLAG_RW,
1163 	    &rack_do_dyn_mul, 0,
1164 	    "Rack timely do we enable dynmaic timely goodput by default");
1165 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1166 	    SYSCTL_CHILDREN(rack_timely),
1167 	    OID_AUTO, "no_rec_red", CTLFLAG_RW,
1168 	    &rack_gp_no_rec_chg, 1,
1169 	    "Rack timely do we prohibit the recovery multiplier from being lowered");
1170 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1171 	    SYSCTL_CHILDREN(rack_timely),
1172 	    OID_AUTO, "red_clear_cnt", CTLFLAG_RW,
1173 	    &rack_timely_dec_clear, 6,
1174 	    "Rack timely what threshold do we count to before another boost during b/w decent");
1175 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1176 	    SYSCTL_CHILDREN(rack_timely),
1177 	    OID_AUTO, "max_push_rise", CTLFLAG_RW,
1178 	    &rack_timely_max_push_rise, 3,
1179 	    "Rack timely how many times do we push up with b/w increase");
1180 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1181 	    SYSCTL_CHILDREN(rack_timely),
1182 	    OID_AUTO, "max_push_drop", CTLFLAG_RW,
1183 	    &rack_timely_max_push_drop, 3,
1184 	    "Rack timely how many times do we push back on b/w decent");
1185 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1186 	    SYSCTL_CHILDREN(rack_timely),
1187 	    OID_AUTO, "min_segs", CTLFLAG_RW,
1188 	    &rack_timely_min_segs, 4,
1189 	    "Rack timely when setting the cwnd what is the min num segments");
1190 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1191 	    SYSCTL_CHILDREN(rack_timely),
1192 	    OID_AUTO, "noback_max", CTLFLAG_RW,
1193 	    &rack_use_max_for_nobackoff, 0,
1194 	    "Rack timely when deciding if to backoff on a loss, do we use under max rtt else min");
1195 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1196 	    SYSCTL_CHILDREN(rack_timely),
1197 	    OID_AUTO, "interim_timely_only", CTLFLAG_RW,
1198 	    &rack_timely_int_timely_only, 0,
1199 	    "Rack timely when doing interim timely's do we only do timely (no b/w consideration)");
1200 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1201 	    SYSCTL_CHILDREN(rack_timely),
1202 	    OID_AUTO, "nonstop", CTLFLAG_RW,
1203 	    &rack_timely_no_stopping, 0,
1204 	    "Rack timely don't stop increase");
1205 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1206 	    SYSCTL_CHILDREN(rack_timely),
1207 	    OID_AUTO, "dec_raise_thresh", CTLFLAG_RW,
1208 	    &rack_down_raise_thresh, 100,
1209 	    "If the CA or SS is below this threshold raise on the first 3 b/w lowers (0=always)");
1210 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1211 	    SYSCTL_CHILDREN(rack_timely),
1212 	    OID_AUTO, "bottom_drag_segs", CTLFLAG_RW,
1213 	    &rack_req_segs, 1,
1214 	    "Bottom dragging if not these many segments outstanding and room");
1215 
1216 	/* TLP and Rack related parameters */
1217 	rack_tlp = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1218 	    SYSCTL_CHILDREN(rack_sysctl_root),
1219 	    OID_AUTO,
1220 	    "tlp",
1221 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1222 	    "TLP and Rack related Controls");
1223 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1224 	    SYSCTL_CHILDREN(rack_tlp),
1225 	    OID_AUTO, "use_rrr", CTLFLAG_RW,
1226 	    &use_rack_rr, 1,
1227 	    "Do we use Rack Rapid Recovery");
1228 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1229 	    SYSCTL_CHILDREN(rack_tlp),
1230 	    OID_AUTO, "post_rec_labc", CTLFLAG_RW,
1231 	    &rack_max_abc_post_recovery, 2,
1232 	    "Since we do early recovery, do we override the l_abc to a value, if so what?");
1233 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1234 	    SYSCTL_CHILDREN(rack_tlp),
1235 	    OID_AUTO, "nonrxt_use_cr", CTLFLAG_RW,
1236 	    &rack_non_rxt_use_cr, 0,
1237 	    "Do we use ss/ca rate if in recovery we are transmitting a new data chunk");
1238 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1239 	    SYSCTL_CHILDREN(rack_tlp),
1240 	    OID_AUTO, "tlpmethod", CTLFLAG_RW,
1241 	    &rack_tlp_threshold_use, TLP_USE_TWO_ONE,
1242 	    "What method do we do for TLP time calc 0=no-de-ack-comp, 1=ID, 2=2.1, 3=2.2");
1243 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1244 	    SYSCTL_CHILDREN(rack_tlp),
1245 	    OID_AUTO, "limit", CTLFLAG_RW,
1246 	    &rack_tlp_limit, 2,
1247 	    "How many TLP's can be sent without sending new data");
1248 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1249 	    SYSCTL_CHILDREN(rack_tlp),
1250 	    OID_AUTO, "use_greater", CTLFLAG_RW,
1251 	    &rack_tlp_use_greater, 1,
1252 	    "Should we use the rack_rtt time if its greater than srtt");
1253 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1254 	    SYSCTL_CHILDREN(rack_tlp),
1255 	    OID_AUTO, "tlpminto", CTLFLAG_RW,
1256 	    &rack_tlp_min, 10000,
1257 	    "TLP minimum timeout per the specification (in microseconds)");
1258 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1259 	    SYSCTL_CHILDREN(rack_tlp),
1260 	    OID_AUTO, "send_oldest", CTLFLAG_RW,
1261 	    &rack_always_send_oldest, 0,
1262 	    "Should we always send the oldest TLP and RACK-TLP");
1263 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1264 	    SYSCTL_CHILDREN(rack_tlp),
1265 	    OID_AUTO, "rack_tlimit", CTLFLAG_RW,
1266 	    &rack_limited_retran, 0,
1267 	    "How many times can a rack timeout drive out sends");
1268 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1269 	    SYSCTL_CHILDREN(rack_tlp),
1270 	    OID_AUTO, "tlp_cwnd_flag", CTLFLAG_RW,
1271 	    &rack_lower_cwnd_at_tlp, 0,
1272 	    "When a TLP completes a retran should we enter recovery");
1273 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1274 	    SYSCTL_CHILDREN(rack_tlp),
1275 	    OID_AUTO, "reorder_thresh", CTLFLAG_RW,
1276 	    &rack_reorder_thresh, 2,
1277 	    "What factor for rack will be added when seeing reordering (shift right)");
1278 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1279 	    SYSCTL_CHILDREN(rack_tlp),
1280 	    OID_AUTO, "rtt_tlp_thresh", CTLFLAG_RW,
1281 	    &rack_tlp_thresh, 1,
1282 	    "What divisor for TLP rtt/retran will be added (1=rtt, 2=1/2 rtt etc)");
1283 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1284 	    SYSCTL_CHILDREN(rack_tlp),
1285 	    OID_AUTO, "reorder_fade", CTLFLAG_RW,
1286 	    &rack_reorder_fade, 60000000,
1287 	    "Does reorder detection fade, if so how many microseconds (0 means never)");
1288 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1289 	    SYSCTL_CHILDREN(rack_tlp),
1290 	    OID_AUTO, "pktdelay", CTLFLAG_RW,
1291 	    &rack_pkt_delay, 1000,
1292 	    "Extra RACK time (in microseconds) besides reordering thresh");
1293 
1294 	/* Timer related controls */
1295 	rack_timers = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1296 	    SYSCTL_CHILDREN(rack_sysctl_root),
1297 	    OID_AUTO,
1298 	    "timers",
1299 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1300 	    "Timer related controls");
1301 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1302 	    SYSCTL_CHILDREN(rack_timers),
1303 	    OID_AUTO, "persmin", CTLFLAG_RW,
1304 	    &rack_persist_min, 250000,
1305 	    "What is the minimum time in microseconds between persists");
1306 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1307 	    SYSCTL_CHILDREN(rack_timers),
1308 	    OID_AUTO, "persmax", CTLFLAG_RW,
1309 	    &rack_persist_max, 2000000,
1310 	    "What is the largest delay in microseconds between persists");
1311 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1312 	    SYSCTL_CHILDREN(rack_timers),
1313 	    OID_AUTO, "delayed_ack", CTLFLAG_RW,
1314 	    &rack_delayed_ack_time, 40000,
1315 	    "Delayed ack time (40ms in microseconds)");
1316 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1317 	    SYSCTL_CHILDREN(rack_timers),
1318 	    OID_AUTO, "minrto", CTLFLAG_RW,
1319 	    &rack_rto_min, 30000,
1320 	    "Minimum RTO in microseconds -- set with caution below 1000 due to TLP");
1321 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1322 	    SYSCTL_CHILDREN(rack_timers),
1323 	    OID_AUTO, "maxrto", CTLFLAG_RW,
1324 	    &rack_rto_max, 4000000,
1325 	    "Maximum RTO in microseconds -- should be at least as large as min_rto");
1326 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1327 	    SYSCTL_CHILDREN(rack_timers),
1328 	    OID_AUTO, "minto", CTLFLAG_RW,
1329 	    &rack_min_to, 1000,
1330 	    "Minimum rack timeout in microseconds");
1331 	/* Measure controls */
1332 	rack_measure = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1333 	    SYSCTL_CHILDREN(rack_sysctl_root),
1334 	    OID_AUTO,
1335 	    "measure",
1336 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1337 	    "Measure related controls");
1338 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1339 	    SYSCTL_CHILDREN(rack_measure),
1340 	    OID_AUTO, "wma_divisor", CTLFLAG_RW,
1341 	    &rack_wma_divisor, 8,
1342 	    "When doing b/w calculation what is the  divisor for the WMA");
1343 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1344 	    SYSCTL_CHILDREN(rack_measure),
1345 	    OID_AUTO, "end_cwnd", CTLFLAG_RW,
1346 	    &rack_cwnd_block_ends_measure, 0,
1347 	    "Does a cwnd just-return end the measurement window (app limited)");
1348 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1349 	    SYSCTL_CHILDREN(rack_measure),
1350 	    OID_AUTO, "end_rwnd", CTLFLAG_RW,
1351 	    &rack_rwnd_block_ends_measure, 0,
1352 	    "Does an rwnd just-return end the measurement window (app limited -- not persists)");
1353 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1354 	    SYSCTL_CHILDREN(rack_measure),
1355 	    OID_AUTO, "min_target", CTLFLAG_RW,
1356 	    &rack_def_data_window, 20,
1357 	    "What is the minimum target window (in mss) for a GP measurements");
1358 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1359 	    SYSCTL_CHILDREN(rack_measure),
1360 	    OID_AUTO, "goal_bdp", CTLFLAG_RW,
1361 	    &rack_goal_bdp, 2,
1362 	    "What is the goal BDP to measure");
1363 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1364 	    SYSCTL_CHILDREN(rack_measure),
1365 	    OID_AUTO, "min_srtts", CTLFLAG_RW,
1366 	    &rack_min_srtts, 1,
1367 	    "What is the goal BDP to measure");
1368 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1369 	    SYSCTL_CHILDREN(rack_measure),
1370 	    OID_AUTO, "min_measure_tim", CTLFLAG_RW,
1371 	    &rack_min_measure_usec, 0,
1372 	    "What is the Minimum time time for a measurement if 0, this is off");
1373 	/* Features */
1374 	rack_features = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1375 	    SYSCTL_CHILDREN(rack_sysctl_root),
1376 	    OID_AUTO,
1377 	    "features",
1378 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1379 	    "Feature controls");
1380 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1381 	    SYSCTL_CHILDREN(rack_features),
1382 	    OID_AUTO, "cmpack", CTLFLAG_RW,
1383 	    &rack_use_cmp_acks, 1,
1384 	    "Should RACK have LRO send compressed acks");
1385 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1386 	    SYSCTL_CHILDREN(rack_features),
1387 	    OID_AUTO, "fsb", CTLFLAG_RW,
1388 	    &rack_use_fsb, 1,
1389 	    "Should RACK use the fast send block?");
1390 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1391 	    SYSCTL_CHILDREN(rack_features),
1392 	    OID_AUTO, "rfo", CTLFLAG_RW,
1393 	    &rack_use_rfo, 1,
1394 	    "Should RACK use rack_fast_output()?");
1395 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1396 	    SYSCTL_CHILDREN(rack_features),
1397 	    OID_AUTO, "rsmrfo", CTLFLAG_RW,
1398 	    &rack_use_rsm_rfo, 1,
1399 	    "Should RACK use rack_fast_rsm_output()?");
1400 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1401 	    SYSCTL_CHILDREN(rack_features),
1402 	    OID_AUTO, "non_paced_lro_queue", CTLFLAG_RW,
1403 	    &rack_enable_mqueue_for_nonpaced, 0,
1404 	    "Should RACK use mbuf queuing for non-paced connections");
1405 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1406 	    SYSCTL_CHILDREN(rack_features),
1407 	    OID_AUTO, "hystartplusplus", CTLFLAG_RW,
1408 	    &rack_do_hystart, 0,
1409 	    "Should RACK enable HyStart++ on connections?");
1410 	/* Misc rack controls */
1411 	rack_misc = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1412 	    SYSCTL_CHILDREN(rack_sysctl_root),
1413 	    OID_AUTO,
1414 	    "misc",
1415 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1416 	    "Misc related controls");
1417 #ifdef TCP_ACCOUNTING
1418 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1419 	    SYSCTL_CHILDREN(rack_misc),
1420 	    OID_AUTO, "tcp_acct", CTLFLAG_RW,
1421 	    &rack_tcp_accounting, 0,
1422 	    "Should we turn on TCP accounting for all rack sessions?");
1423 #endif
1424 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1425 	    SYSCTL_CHILDREN(rack_misc),
1426 	    OID_AUTO, "apply_rtt_with_low_conf", CTLFLAG_RW,
1427 	    &rack_apply_rtt_with_reduced_conf, 0,
1428 	    "When a persist or keep-alive probe is not answered do we calculate rtt on subsequent answers?");
1429 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1430 	    SYSCTL_CHILDREN(rack_misc),
1431 	    OID_AUTO, "rack_dsack_ctl", CTLFLAG_RW,
1432 	    &rack_dsack_std_based, 3,
1433 	    "How do we process dsack with respect to rack timers, bit field, 3 is standards based?");
1434 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1435 	    SYSCTL_CHILDREN(rack_misc),
1436 	    OID_AUTO, "prr_addback_max", CTLFLAG_RW,
1437 	    &rack_prr_addbackmax, 2,
1438 	    "What is the maximum number of MSS we allow to be added back if prr can't send all its data?");
1439 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1440 	    SYSCTL_CHILDREN(rack_misc),
1441 	    OID_AUTO, "stats_gets_ms", CTLFLAG_RW,
1442 	    &rack_stats_gets_ms_rtt, 1,
1443 	    "What do we feed the stats framework (1 = ms_rtt, 0 = us_rtt, 2 = ms_rtt from hdwr, > 2 usec rtt from hdwr)?");
1444 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1445 	    SYSCTL_CHILDREN(rack_misc),
1446 	    OID_AUTO, "clientlowbuf", CTLFLAG_RW,
1447 	    &rack_client_low_buf, 0,
1448 	    "Client low buffer level (below this we are more aggressive in DGP exiting recovery (0 = off)?");
1449 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1450 	    SYSCTL_CHILDREN(rack_misc),
1451 	    OID_AUTO, "defprofile", CTLFLAG_RW,
1452 	    &rack_def_profile, 0,
1453 	    "Should RACK use a default profile (0=no, num == profile num)?");
1454 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1455 	    SYSCTL_CHILDREN(rack_misc),
1456 	    OID_AUTO, "shared_cwnd", CTLFLAG_RW,
1457 	    &rack_enable_shared_cwnd, 1,
1458 	    "Should RACK try to use the shared cwnd on connections where allowed");
1459 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1460 	    SYSCTL_CHILDREN(rack_misc),
1461 	    OID_AUTO, "limits_on_scwnd", CTLFLAG_RW,
1462 	    &rack_limits_scwnd, 1,
1463 	    "Should RACK place low end time limits on the shared cwnd feature");
1464 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1465 	    SYSCTL_CHILDREN(rack_misc),
1466 	    OID_AUTO, "iMac_dack", CTLFLAG_RW,
1467 	    &rack_use_imac_dack, 0,
1468 	    "Should RACK try to emulate iMac delayed ack");
1469 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1470 	    SYSCTL_CHILDREN(rack_misc),
1471 	    OID_AUTO, "no_prr", CTLFLAG_RW,
1472 	    &rack_disable_prr, 0,
1473 	    "Should RACK not use prr and only pace (must have pacing on)");
1474 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1475 	    SYSCTL_CHILDREN(rack_misc),
1476 	    OID_AUTO, "bb_verbose", CTLFLAG_RW,
1477 	    &rack_verbose_logging, 0,
1478 	    "Should RACK black box logging be verbose");
1479 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1480 	    SYSCTL_CHILDREN(rack_misc),
1481 	    OID_AUTO, "data_after_close", CTLFLAG_RW,
1482 	    &rack_ignore_data_after_close, 1,
1483 	    "Do we hold off sending a RST until all pending data is ack'd");
1484 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1485 	    SYSCTL_CHILDREN(rack_misc),
1486 	    OID_AUTO, "no_sack_needed", CTLFLAG_RW,
1487 	    &rack_sack_not_required, 1,
1488 	    "Do we allow rack to run on connections not supporting SACK");
1489 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1490 	    SYSCTL_CHILDREN(rack_misc),
1491 	    OID_AUTO, "prr_sendalot", CTLFLAG_RW,
1492 	    &rack_send_a_lot_in_prr, 1,
1493 	    "Send a lot in prr");
1494 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1495 	    SYSCTL_CHILDREN(rack_misc),
1496 	    OID_AUTO, "autoscale", CTLFLAG_RW,
1497 	    &rack_autosndbuf_inc, 20,
1498 	    "What percentage should rack scale up its snd buffer by?");
1499 	/* Sack Attacker detection stuff */
1500 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1501 	    SYSCTL_CHILDREN(rack_attack),
1502 	    OID_AUTO, "detect_highsackratio", CTLFLAG_RW,
1503 	    &rack_highest_sack_thresh_seen, 0,
1504 	    "Highest sack to ack ratio seen");
1505 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1506 	    SYSCTL_CHILDREN(rack_attack),
1507 	    OID_AUTO, "detect_highmoveratio", CTLFLAG_RW,
1508 	    &rack_highest_move_thresh_seen, 0,
1509 	    "Highest move to non-move ratio seen");
1510 	rack_ack_total = counter_u64_alloc(M_WAITOK);
1511 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1512 	    SYSCTL_CHILDREN(rack_attack),
1513 	    OID_AUTO, "acktotal", CTLFLAG_RD,
1514 	    &rack_ack_total,
1515 	    "Total number of Ack's");
1516 	rack_express_sack = counter_u64_alloc(M_WAITOK);
1517 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1518 	    SYSCTL_CHILDREN(rack_attack),
1519 	    OID_AUTO, "exp_sacktotal", CTLFLAG_RD,
1520 	    &rack_express_sack,
1521 	    "Total expresss number of Sack's");
1522 	rack_sack_total = counter_u64_alloc(M_WAITOK);
1523 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1524 	    SYSCTL_CHILDREN(rack_attack),
1525 	    OID_AUTO, "sacktotal", CTLFLAG_RD,
1526 	    &rack_sack_total,
1527 	    "Total number of SACKs");
1528 	rack_move_none = counter_u64_alloc(M_WAITOK);
1529 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1530 	    SYSCTL_CHILDREN(rack_attack),
1531 	    OID_AUTO, "move_none", CTLFLAG_RD,
1532 	    &rack_move_none,
1533 	    "Total number of SACK index reuse of postions under threshold");
1534 	rack_move_some = counter_u64_alloc(M_WAITOK);
1535 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1536 	    SYSCTL_CHILDREN(rack_attack),
1537 	    OID_AUTO, "move_some", CTLFLAG_RD,
1538 	    &rack_move_some,
1539 	    "Total number of SACK index reuse of postions over threshold");
1540 	rack_sack_attacks_detected = counter_u64_alloc(M_WAITOK);
1541 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1542 	    SYSCTL_CHILDREN(rack_attack),
1543 	    OID_AUTO, "attacks", CTLFLAG_RD,
1544 	    &rack_sack_attacks_detected,
1545 	    "Total number of SACK attackers that had sack disabled");
1546 	rack_sack_attacks_reversed = counter_u64_alloc(M_WAITOK);
1547 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1548 	    SYSCTL_CHILDREN(rack_attack),
1549 	    OID_AUTO, "reversed", CTLFLAG_RD,
1550 	    &rack_sack_attacks_reversed,
1551 	    "Total number of SACK attackers that were later determined false positive");
1552 	rack_sack_used_next_merge = counter_u64_alloc(M_WAITOK);
1553 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1554 	    SYSCTL_CHILDREN(rack_attack),
1555 	    OID_AUTO, "nextmerge", CTLFLAG_RD,
1556 	    &rack_sack_used_next_merge,
1557 	    "Total number of times we used the next merge");
1558 	rack_sack_used_prev_merge = counter_u64_alloc(M_WAITOK);
1559 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1560 	    SYSCTL_CHILDREN(rack_attack),
1561 	    OID_AUTO, "prevmerge", CTLFLAG_RD,
1562 	    &rack_sack_used_prev_merge,
1563 	    "Total number of times we used the prev merge");
1564 	/* Counters */
1565 	rack_fto_send = counter_u64_alloc(M_WAITOK);
1566 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1567 	    SYSCTL_CHILDREN(rack_counters),
1568 	    OID_AUTO, "fto_send", CTLFLAG_RD,
1569 	    &rack_fto_send, "Total number of rack_fast_output sends");
1570 	rack_fto_rsm_send = counter_u64_alloc(M_WAITOK);
1571 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1572 	    SYSCTL_CHILDREN(rack_counters),
1573 	    OID_AUTO, "fto_rsm_send", CTLFLAG_RD,
1574 	    &rack_fto_rsm_send, "Total number of rack_fast_rsm_output sends");
1575 	rack_nfto_resend = counter_u64_alloc(M_WAITOK);
1576 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1577 	    SYSCTL_CHILDREN(rack_counters),
1578 	    OID_AUTO, "nfto_resend", CTLFLAG_RD,
1579 	    &rack_nfto_resend, "Total number of rack_output retransmissions");
1580 	rack_non_fto_send = counter_u64_alloc(M_WAITOK);
1581 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1582 	    SYSCTL_CHILDREN(rack_counters),
1583 	    OID_AUTO, "nfto_send", CTLFLAG_RD,
1584 	    &rack_non_fto_send, "Total number of rack_output first sends");
1585 	rack_extended_rfo = counter_u64_alloc(M_WAITOK);
1586 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1587 	    SYSCTL_CHILDREN(rack_counters),
1588 	    OID_AUTO, "rfo_extended", CTLFLAG_RD,
1589 	    &rack_extended_rfo, "Total number of times we extended rfo");
1590 
1591 	rack_hw_pace_init_fail = counter_u64_alloc(M_WAITOK);
1592 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1593 	    SYSCTL_CHILDREN(rack_counters),
1594 	    OID_AUTO, "hwpace_init_fail", CTLFLAG_RD,
1595 	    &rack_hw_pace_init_fail, "Total number of times we failed to initialize hw pacing");
1596 	rack_hw_pace_lost = counter_u64_alloc(M_WAITOK);
1597 
1598 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1599 	    SYSCTL_CHILDREN(rack_counters),
1600 	    OID_AUTO, "hwpace_lost", CTLFLAG_RD,
1601 	    &rack_hw_pace_lost, "Total number of times we failed to initialize hw pacing");
1602 	rack_badfr = counter_u64_alloc(M_WAITOK);
1603 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1604 	    SYSCTL_CHILDREN(rack_counters),
1605 	    OID_AUTO, "badfr", CTLFLAG_RD,
1606 	    &rack_badfr, "Total number of bad FRs");
1607 	rack_badfr_bytes = counter_u64_alloc(M_WAITOK);
1608 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1609 	    SYSCTL_CHILDREN(rack_counters),
1610 	    OID_AUTO, "badfr_bytes", CTLFLAG_RD,
1611 	    &rack_badfr_bytes, "Total number of bad FRs");
1612 	rack_rtm_prr_retran = counter_u64_alloc(M_WAITOK);
1613 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1614 	    SYSCTL_CHILDREN(rack_counters),
1615 	    OID_AUTO, "prrsndret", CTLFLAG_RD,
1616 	    &rack_rtm_prr_retran,
1617 	    "Total number of prr based retransmits");
1618 	rack_rtm_prr_newdata = counter_u64_alloc(M_WAITOK);
1619 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1620 	    SYSCTL_CHILDREN(rack_counters),
1621 	    OID_AUTO, "prrsndnew", CTLFLAG_RD,
1622 	    &rack_rtm_prr_newdata,
1623 	    "Total number of prr based new transmits");
1624 	rack_timestamp_mismatch = counter_u64_alloc(M_WAITOK);
1625 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1626 	    SYSCTL_CHILDREN(rack_counters),
1627 	    OID_AUTO, "tsnf", CTLFLAG_RD,
1628 	    &rack_timestamp_mismatch,
1629 	    "Total number of timestamps that we could not find the reported ts");
1630 	rack_find_high = counter_u64_alloc(M_WAITOK);
1631 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1632 	    SYSCTL_CHILDREN(rack_counters),
1633 	    OID_AUTO, "findhigh", CTLFLAG_RD,
1634 	    &rack_find_high,
1635 	    "Total number of FIN causing find-high");
1636 	rack_reorder_seen = counter_u64_alloc(M_WAITOK);
1637 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1638 	    SYSCTL_CHILDREN(rack_counters),
1639 	    OID_AUTO, "reordering", CTLFLAG_RD,
1640 	    &rack_reorder_seen,
1641 	    "Total number of times we added delay due to reordering");
1642 	rack_tlp_tot = counter_u64_alloc(M_WAITOK);
1643 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1644 	    SYSCTL_CHILDREN(rack_counters),
1645 	    OID_AUTO, "tlp_to_total", CTLFLAG_RD,
1646 	    &rack_tlp_tot,
1647 	    "Total number of tail loss probe expirations");
1648 	rack_tlp_newdata = counter_u64_alloc(M_WAITOK);
1649 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1650 	    SYSCTL_CHILDREN(rack_counters),
1651 	    OID_AUTO, "tlp_new", CTLFLAG_RD,
1652 	    &rack_tlp_newdata,
1653 	    "Total number of tail loss probe sending new data");
1654 	rack_tlp_retran = counter_u64_alloc(M_WAITOK);
1655 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1656 	    SYSCTL_CHILDREN(rack_counters),
1657 	    OID_AUTO, "tlp_retran", CTLFLAG_RD,
1658 	    &rack_tlp_retran,
1659 	    "Total number of tail loss probe sending retransmitted data");
1660 	rack_tlp_retran_bytes = counter_u64_alloc(M_WAITOK);
1661 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1662 	    SYSCTL_CHILDREN(rack_counters),
1663 	    OID_AUTO, "tlp_retran_bytes", CTLFLAG_RD,
1664 	    &rack_tlp_retran_bytes,
1665 	    "Total bytes of tail loss probe sending retransmitted data");
1666 	rack_tlp_retran_fail = counter_u64_alloc(M_WAITOK);
1667 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1668 	    SYSCTL_CHILDREN(rack_counters),
1669 	    OID_AUTO, "tlp_retran_fail", CTLFLAG_RD,
1670 	    &rack_tlp_retran_fail,
1671 	    "Total number of tail loss probe sending retransmitted data that failed (wait for t3)");
1672 	rack_to_tot = counter_u64_alloc(M_WAITOK);
1673 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1674 	    SYSCTL_CHILDREN(rack_counters),
1675 	    OID_AUTO, "rack_to_tot", CTLFLAG_RD,
1676 	    &rack_to_tot,
1677 	    "Total number of times the rack to expired");
1678 	rack_to_arm_rack = counter_u64_alloc(M_WAITOK);
1679 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1680 	    SYSCTL_CHILDREN(rack_counters),
1681 	    OID_AUTO, "arm_rack", CTLFLAG_RD,
1682 	    &rack_to_arm_rack,
1683 	    "Total number of times the rack timer armed");
1684 	rack_to_arm_tlp = counter_u64_alloc(M_WAITOK);
1685 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1686 	    SYSCTL_CHILDREN(rack_counters),
1687 	    OID_AUTO, "arm_tlp", CTLFLAG_RD,
1688 	    &rack_to_arm_tlp,
1689 	    "Total number of times the tlp timer armed");
1690 	rack_calc_zero = counter_u64_alloc(M_WAITOK);
1691 	rack_calc_nonzero = counter_u64_alloc(M_WAITOK);
1692 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1693 	    SYSCTL_CHILDREN(rack_counters),
1694 	    OID_AUTO, "calc_zero", CTLFLAG_RD,
1695 	    &rack_calc_zero,
1696 	    "Total number of times pacing time worked out to zero");
1697 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1698 	    SYSCTL_CHILDREN(rack_counters),
1699 	    OID_AUTO, "calc_nonzero", CTLFLAG_RD,
1700 	    &rack_calc_nonzero,
1701 	    "Total number of times pacing time worked out to non-zero");
1702 	rack_paced_segments = counter_u64_alloc(M_WAITOK);
1703 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1704 	    SYSCTL_CHILDREN(rack_counters),
1705 	    OID_AUTO, "paced", CTLFLAG_RD,
1706 	    &rack_paced_segments,
1707 	    "Total number of times a segment send caused hptsi");
1708 	rack_unpaced_segments = counter_u64_alloc(M_WAITOK);
1709 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1710 	    SYSCTL_CHILDREN(rack_counters),
1711 	    OID_AUTO, "unpaced", CTLFLAG_RD,
1712 	    &rack_unpaced_segments,
1713 	    "Total number of times a segment did not cause hptsi");
1714 	rack_saw_enobuf = counter_u64_alloc(M_WAITOK);
1715 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1716 	    SYSCTL_CHILDREN(rack_counters),
1717 	    OID_AUTO, "saw_enobufs", CTLFLAG_RD,
1718 	    &rack_saw_enobuf,
1719 	    "Total number of times a sends returned enobuf for non-hdwr paced connections");
1720 	rack_saw_enobuf_hw = counter_u64_alloc(M_WAITOK);
1721 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1722 	    SYSCTL_CHILDREN(rack_counters),
1723 	    OID_AUTO, "saw_enobufs_hw", CTLFLAG_RD,
1724 	    &rack_saw_enobuf_hw,
1725 	    "Total number of times a send returned enobuf for hdwr paced connections");
1726 	rack_saw_enetunreach = counter_u64_alloc(M_WAITOK);
1727 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1728 	    SYSCTL_CHILDREN(rack_counters),
1729 	    OID_AUTO, "saw_enetunreach", CTLFLAG_RD,
1730 	    &rack_saw_enetunreach,
1731 	    "Total number of times a send received a enetunreachable");
1732 	rack_hot_alloc = counter_u64_alloc(M_WAITOK);
1733 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1734 	    SYSCTL_CHILDREN(rack_counters),
1735 	    OID_AUTO, "alloc_hot", CTLFLAG_RD,
1736 	    &rack_hot_alloc,
1737 	    "Total allocations from the top of our list");
1738 	rack_to_alloc = counter_u64_alloc(M_WAITOK);
1739 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1740 	    SYSCTL_CHILDREN(rack_counters),
1741 	    OID_AUTO, "allocs", CTLFLAG_RD,
1742 	    &rack_to_alloc,
1743 	    "Total allocations of tracking structures");
1744 	rack_to_alloc_hard = counter_u64_alloc(M_WAITOK);
1745 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1746 	    SYSCTL_CHILDREN(rack_counters),
1747 	    OID_AUTO, "allochard", CTLFLAG_RD,
1748 	    &rack_to_alloc_hard,
1749 	    "Total allocations done with sleeping the hard way");
1750 	rack_to_alloc_emerg = counter_u64_alloc(M_WAITOK);
1751 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1752 	    SYSCTL_CHILDREN(rack_counters),
1753 	    OID_AUTO, "allocemerg", CTLFLAG_RD,
1754 	    &rack_to_alloc_emerg,
1755 	    "Total allocations done from emergency cache");
1756 	rack_to_alloc_limited = counter_u64_alloc(M_WAITOK);
1757 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1758 	    SYSCTL_CHILDREN(rack_counters),
1759 	    OID_AUTO, "alloc_limited", CTLFLAG_RD,
1760 	    &rack_to_alloc_limited,
1761 	    "Total allocations dropped due to limit");
1762 	rack_alloc_limited_conns = counter_u64_alloc(M_WAITOK);
1763 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1764 	    SYSCTL_CHILDREN(rack_counters),
1765 	    OID_AUTO, "alloc_limited_conns", CTLFLAG_RD,
1766 	    &rack_alloc_limited_conns,
1767 	    "Connections with allocations dropped due to limit");
1768 	rack_split_limited = counter_u64_alloc(M_WAITOK);
1769 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1770 	    SYSCTL_CHILDREN(rack_counters),
1771 	    OID_AUTO, "split_limited", CTLFLAG_RD,
1772 	    &rack_split_limited,
1773 	    "Split allocations dropped due to limit");
1774 
1775 	for (i = 0; i < MAX_NUM_OF_CNTS; i++) {
1776 		char name[32];
1777 		sprintf(name, "cmp_ack_cnt_%d", i);
1778 		rack_proc_comp_ack[i] = counter_u64_alloc(M_WAITOK);
1779 		SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1780 				       SYSCTL_CHILDREN(rack_counters),
1781 				       OID_AUTO, name, CTLFLAG_RD,
1782 				       &rack_proc_comp_ack[i],
1783 				       "Number of compressed acks we processed");
1784 	}
1785 	rack_large_ackcmp = counter_u64_alloc(M_WAITOK);
1786 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1787 	    SYSCTL_CHILDREN(rack_counters),
1788 	    OID_AUTO, "cmp_large_mbufs", CTLFLAG_RD,
1789 	    &rack_large_ackcmp,
1790 	    "Number of TCP connections with large mbuf's for compressed acks");
1791 	rack_persists_sends = counter_u64_alloc(M_WAITOK);
1792 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1793 	    SYSCTL_CHILDREN(rack_counters),
1794 	    OID_AUTO, "persist_sends", CTLFLAG_RD,
1795 	    &rack_persists_sends,
1796 	    "Number of times we sent a persist probe");
1797 	rack_persists_acks = counter_u64_alloc(M_WAITOK);
1798 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1799 	    SYSCTL_CHILDREN(rack_counters),
1800 	    OID_AUTO, "persist_acks", CTLFLAG_RD,
1801 	    &rack_persists_acks,
1802 	    "Number of times a persist probe was acked");
1803 	rack_persists_loss = counter_u64_alloc(M_WAITOK);
1804 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1805 	    SYSCTL_CHILDREN(rack_counters),
1806 	    OID_AUTO, "persist_loss", CTLFLAG_RD,
1807 	    &rack_persists_loss,
1808 	    "Number of times we detected a lost persist probe (no ack)");
1809 	rack_persists_lost_ends = counter_u64_alloc(M_WAITOK);
1810 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1811 	    SYSCTL_CHILDREN(rack_counters),
1812 	    OID_AUTO, "persist_loss_ends", CTLFLAG_RD,
1813 	    &rack_persists_lost_ends,
1814 	    "Number of lost persist probe (no ack) that the run ended with a PERSIST abort");
1815 	rack_small_ackcmp = counter_u64_alloc(M_WAITOK);
1816 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1817 	    SYSCTL_CHILDREN(rack_counters),
1818 	    OID_AUTO, "cmp_small_mbufs", CTLFLAG_RD,
1819 	    &rack_small_ackcmp,
1820 	    "Number of TCP connections with small mbuf's for compressed acks");
1821 #ifdef INVARIANTS
1822 	rack_adjust_map_bw = counter_u64_alloc(M_WAITOK);
1823 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1824 	    SYSCTL_CHILDREN(rack_counters),
1825 	    OID_AUTO, "map_adjust_req", CTLFLAG_RD,
1826 	    &rack_adjust_map_bw,
1827 	    "Number of times we hit the case where the sb went up and down on a sendmap entry");
1828 #endif
1829 	rack_multi_single_eq = counter_u64_alloc(M_WAITOK);
1830 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1831 	    SYSCTL_CHILDREN(rack_counters),
1832 	    OID_AUTO, "cmp_ack_equiv", CTLFLAG_RD,
1833 	    &rack_multi_single_eq,
1834 	    "Number of compressed acks total represented");
1835 	rack_proc_non_comp_ack = counter_u64_alloc(M_WAITOK);
1836 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1837 	    SYSCTL_CHILDREN(rack_counters),
1838 	    OID_AUTO, "cmp_ack_not", CTLFLAG_RD,
1839 	    &rack_proc_non_comp_ack,
1840 	    "Number of non compresseds acks that we processed");
1841 
1842 
1843 	rack_sack_proc_all = counter_u64_alloc(M_WAITOK);
1844 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1845 	    SYSCTL_CHILDREN(rack_counters),
1846 	    OID_AUTO, "sack_long", CTLFLAG_RD,
1847 	    &rack_sack_proc_all,
1848 	    "Total times we had to walk whole list for sack processing");
1849 	rack_sack_proc_restart = counter_u64_alloc(M_WAITOK);
1850 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1851 	    SYSCTL_CHILDREN(rack_counters),
1852 	    OID_AUTO, "sack_restart", CTLFLAG_RD,
1853 	    &rack_sack_proc_restart,
1854 	    "Total times we had to walk whole list due to a restart");
1855 	rack_sack_proc_short = counter_u64_alloc(M_WAITOK);
1856 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1857 	    SYSCTL_CHILDREN(rack_counters),
1858 	    OID_AUTO, "sack_short", CTLFLAG_RD,
1859 	    &rack_sack_proc_short,
1860 	    "Total times we took shortcut for sack processing");
1861 	rack_enter_tlp_calc = counter_u64_alloc(M_WAITOK);
1862 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1863 	    SYSCTL_CHILDREN(rack_counters),
1864 	    OID_AUTO, "tlp_calc_entered", CTLFLAG_RD,
1865 	    &rack_enter_tlp_calc,
1866 	    "Total times we called calc-tlp");
1867 	rack_used_tlpmethod = counter_u64_alloc(M_WAITOK);
1868 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1869 	    SYSCTL_CHILDREN(rack_counters),
1870 	    OID_AUTO, "hit_tlp_method", CTLFLAG_RD,
1871 	    &rack_used_tlpmethod,
1872 	    "Total number of runt sacks");
1873 	rack_used_tlpmethod2 = counter_u64_alloc(M_WAITOK);
1874 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1875 	    SYSCTL_CHILDREN(rack_counters),
1876 	    OID_AUTO, "hit_tlp_method2", CTLFLAG_RD,
1877 	    &rack_used_tlpmethod2,
1878 	    "Total number of times we hit TLP method 2");
1879 	rack_sack_skipped_acked = counter_u64_alloc(M_WAITOK);
1880 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1881 	    SYSCTL_CHILDREN(rack_attack),
1882 	    OID_AUTO, "skipacked", CTLFLAG_RD,
1883 	    &rack_sack_skipped_acked,
1884 	    "Total number of times we skipped previously sacked");
1885 	rack_sack_splits = counter_u64_alloc(M_WAITOK);
1886 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1887 	    SYSCTL_CHILDREN(rack_attack),
1888 	    OID_AUTO, "ofsplit", CTLFLAG_RD,
1889 	    &rack_sack_splits,
1890 	    "Total number of times we did the old fashion tree split");
1891 	rack_progress_drops = counter_u64_alloc(M_WAITOK);
1892 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1893 	    SYSCTL_CHILDREN(rack_counters),
1894 	    OID_AUTO, "prog_drops", CTLFLAG_RD,
1895 	    &rack_progress_drops,
1896 	    "Total number of progress drops");
1897 	rack_input_idle_reduces = counter_u64_alloc(M_WAITOK);
1898 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1899 	    SYSCTL_CHILDREN(rack_counters),
1900 	    OID_AUTO, "idle_reduce_oninput", CTLFLAG_RD,
1901 	    &rack_input_idle_reduces,
1902 	    "Total number of idle reductions on input");
1903 	rack_collapsed_win = counter_u64_alloc(M_WAITOK);
1904 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1905 	    SYSCTL_CHILDREN(rack_counters),
1906 	    OID_AUTO, "collapsed_win", CTLFLAG_RD,
1907 	    &rack_collapsed_win,
1908 	    "Total number of collapsed windows");
1909 	rack_tlp_does_nada = counter_u64_alloc(M_WAITOK);
1910 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1911 	    SYSCTL_CHILDREN(rack_counters),
1912 	    OID_AUTO, "tlp_nada", CTLFLAG_RD,
1913 	    &rack_tlp_does_nada,
1914 	    "Total number of nada tlp calls");
1915 	rack_try_scwnd = counter_u64_alloc(M_WAITOK);
1916 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1917 	    SYSCTL_CHILDREN(rack_counters),
1918 	    OID_AUTO, "tried_scwnd", CTLFLAG_RD,
1919 	    &rack_try_scwnd,
1920 	    "Total number of scwnd attempts");
1921 
1922 	rack_per_timer_hole = counter_u64_alloc(M_WAITOK);
1923 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1924 	    SYSCTL_CHILDREN(rack_counters),
1925 	    OID_AUTO, "timer_hole", CTLFLAG_RD,
1926 	    &rack_per_timer_hole,
1927 	    "Total persists start in timer hole");
1928 
1929 	rack_sbsndptr_wrong = counter_u64_alloc(M_WAITOK);
1930 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1931 	    SYSCTL_CHILDREN(rack_counters),
1932 	    OID_AUTO, "sndptr_wrong", CTLFLAG_RD,
1933 	    &rack_sbsndptr_wrong, "Total number of times the saved sbsndptr was incorret");
1934 	rack_sbsndptr_right = counter_u64_alloc(M_WAITOK);
1935 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1936 	    SYSCTL_CHILDREN(rack_counters),
1937 	    OID_AUTO, "sndptr_right", CTLFLAG_RD,
1938 	    &rack_sbsndptr_right, "Total number of times the saved sbsndptr was corret");
1939 
1940 	COUNTER_ARRAY_ALLOC(rack_out_size, TCP_MSS_ACCT_SIZE, M_WAITOK);
1941 	SYSCTL_ADD_COUNTER_U64_ARRAY(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root),
1942 	    OID_AUTO, "outsize", CTLFLAG_RD,
1943 	    rack_out_size, TCP_MSS_ACCT_SIZE, "MSS send sizes");
1944 	COUNTER_ARRAY_ALLOC(rack_opts_arry, RACK_OPTS_SIZE, M_WAITOK);
1945 	SYSCTL_ADD_COUNTER_U64_ARRAY(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root),
1946 	    OID_AUTO, "opts", CTLFLAG_RD,
1947 	    rack_opts_arry, RACK_OPTS_SIZE, "RACK Option Stats");
1948 	SYSCTL_ADD_PROC(&rack_sysctl_ctx,
1949 	    SYSCTL_CHILDREN(rack_sysctl_root),
1950 	    OID_AUTO, "clear", CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE,
1951 	    &rack_clear_counter, 0, sysctl_rack_clear, "IU", "Clear counters");
1952 }
1953 
1954 static __inline int
1955 rb_map_cmp(struct rack_sendmap *b, struct rack_sendmap *a)
1956 {
1957 	if (SEQ_GEQ(b->r_start, a->r_start) &&
1958 	    SEQ_LT(b->r_start, a->r_end)) {
1959 		/*
1960 		 * The entry b is within the
1961 		 * block a. i.e.:
1962 		 * a --   |-------------|
1963 		 * b --   |----|
1964 		 * <or>
1965 		 * b --       |------|
1966 		 * <or>
1967 		 * b --       |-----------|
1968 		 */
1969 		return (0);
1970 	} else if (SEQ_GEQ(b->r_start, a->r_end)) {
1971 		/*
1972 		 * b falls as either the next
1973 		 * sequence block after a so a
1974 		 * is said to be smaller than b.
1975 		 * i.e:
1976 		 * a --   |------|
1977 		 * b --          |--------|
1978 		 * or
1979 		 * b --              |-----|
1980 		 */
1981 		return (1);
1982 	}
1983 	/*
1984 	 * Whats left is where a is
1985 	 * larger than b. i.e:
1986 	 * a --         |-------|
1987 	 * b --  |---|
1988 	 * or even possibly
1989 	 * b --   |--------------|
1990 	 */
1991 	return (-1);
1992 }
1993 
1994 RB_PROTOTYPE(rack_rb_tree_head, rack_sendmap, r_next, rb_map_cmp);
1995 RB_GENERATE(rack_rb_tree_head, rack_sendmap, r_next, rb_map_cmp);
1996 
1997 static uint32_t
1998 rc_init_window(struct tcp_rack *rack)
1999 {
2000 	uint32_t win;
2001 
2002 	if (rack->rc_init_win == 0) {
2003 		/*
2004 		 * Nothing set by the user, use the system stack
2005 		 * default.
2006 		 */
2007 		return (tcp_compute_initwnd(tcp_maxseg(rack->rc_tp)));
2008 	}
2009 	win = ctf_fixed_maxseg(rack->rc_tp) * rack->rc_init_win;
2010 	return (win);
2011 }
2012 
2013 static uint64_t
2014 rack_get_fixed_pacing_bw(struct tcp_rack *rack)
2015 {
2016 	if (IN_FASTRECOVERY(rack->rc_tp->t_flags))
2017 		return (rack->r_ctl.rc_fixed_pacing_rate_rec);
2018 	else if (rack->r_ctl.cwnd_to_use < rack->rc_tp->snd_ssthresh)
2019 		return (rack->r_ctl.rc_fixed_pacing_rate_ss);
2020 	else
2021 		return (rack->r_ctl.rc_fixed_pacing_rate_ca);
2022 }
2023 
2024 static uint64_t
2025 rack_get_bw(struct tcp_rack *rack)
2026 {
2027 	if (rack->use_fixed_rate) {
2028 		/* Return the fixed pacing rate */
2029 		return (rack_get_fixed_pacing_bw(rack));
2030 	}
2031 	if (rack->r_ctl.gp_bw == 0) {
2032 		/*
2033 		 * We have yet no b/w measurement,
2034 		 * if we have a user set initial bw
2035 		 * return it. If we don't have that and
2036 		 * we have an srtt, use the tcp IW (10) to
2037 		 * calculate a fictional b/w over the SRTT
2038 		 * which is more or less a guess. Note
2039 		 * we don't use our IW from rack on purpose
2040 		 * so if we have like IW=30, we are not
2041 		 * calculating a "huge" b/w.
2042 		 */
2043 		uint64_t bw, srtt;
2044 		if (rack->r_ctl.init_rate)
2045 			return (rack->r_ctl.init_rate);
2046 
2047 		/* Has the user set a max peak rate? */
2048 #ifdef NETFLIX_PEAKRATE
2049 		if (rack->rc_tp->t_maxpeakrate)
2050 			return (rack->rc_tp->t_maxpeakrate);
2051 #endif
2052 		/* Ok lets come up with the IW guess, if we have a srtt */
2053 		if (rack->rc_tp->t_srtt == 0) {
2054 			/*
2055 			 * Go with old pacing method
2056 			 * i.e. burst mitigation only.
2057 			 */
2058 			return (0);
2059 		}
2060 		/* Ok lets get the initial TCP win (not racks) */
2061 		bw = tcp_compute_initwnd(tcp_maxseg(rack->rc_tp));
2062 		srtt = (uint64_t)rack->rc_tp->t_srtt;
2063 		bw *= (uint64_t)USECS_IN_SECOND;
2064 		bw /= srtt;
2065 		if (rack->r_ctl.bw_rate_cap && (bw > rack->r_ctl.bw_rate_cap))
2066 			bw = rack->r_ctl.bw_rate_cap;
2067 		return (bw);
2068 	} else {
2069 		uint64_t bw;
2070 
2071 		if (rack->r_ctl.num_measurements >= RACK_REQ_AVG) {
2072 			/* Averaging is done, we can return the value */
2073 			bw = rack->r_ctl.gp_bw;
2074 		} else {
2075 			/* Still doing initial average must calculate */
2076 			bw = rack->r_ctl.gp_bw / rack->r_ctl.num_measurements;
2077 		}
2078 #ifdef NETFLIX_PEAKRATE
2079 		if ((rack->rc_tp->t_maxpeakrate) &&
2080 		    (bw > rack->rc_tp->t_maxpeakrate)) {
2081 			/* The user has set a peak rate to pace at
2082 			 * don't allow us to pace faster than that.
2083 			 */
2084 			return (rack->rc_tp->t_maxpeakrate);
2085 		}
2086 #endif
2087 		if (rack->r_ctl.bw_rate_cap && (bw > rack->r_ctl.bw_rate_cap))
2088 			bw = rack->r_ctl.bw_rate_cap;
2089 		return (bw);
2090 	}
2091 }
2092 
2093 static uint16_t
2094 rack_get_output_gain(struct tcp_rack *rack, struct rack_sendmap *rsm)
2095 {
2096 	if (rack->use_fixed_rate) {
2097 		return (100);
2098 	} else if (rack->in_probe_rtt && (rsm == NULL))
2099 		return (rack->r_ctl.rack_per_of_gp_probertt);
2100 	else if ((IN_FASTRECOVERY(rack->rc_tp->t_flags) &&
2101 		  rack->r_ctl.rack_per_of_gp_rec)) {
2102 		if (rsm) {
2103 			/* a retransmission always use the recovery rate */
2104 			return (rack->r_ctl.rack_per_of_gp_rec);
2105 		} else if (rack->rack_rec_nonrxt_use_cr) {
2106 			/* Directed to use the configured rate */
2107 			goto configured_rate;
2108 		} else if (rack->rack_no_prr &&
2109 			   (rack->r_ctl.rack_per_of_gp_rec > 100)) {
2110 			/* No PRR, lets just use the b/w estimate only */
2111 			return (100);
2112 		} else {
2113 			/*
2114 			 * Here we may have a non-retransmit but we
2115 			 * have no overrides, so just use the recovery
2116 			 * rate (prr is in effect).
2117 			 */
2118 			return (rack->r_ctl.rack_per_of_gp_rec);
2119 		}
2120 	}
2121 configured_rate:
2122 	/* For the configured rate we look at our cwnd vs the ssthresh */
2123 	if (rack->r_ctl.cwnd_to_use < rack->rc_tp->snd_ssthresh)
2124 		return (rack->r_ctl.rack_per_of_gp_ss);
2125 	else
2126 		return (rack->r_ctl.rack_per_of_gp_ca);
2127 }
2128 
2129 static void
2130 rack_log_dsack_event(struct tcp_rack *rack, uint8_t mod, uint32_t flex4, uint32_t flex5, uint32_t flex6)
2131 {
2132 	/*
2133 	 * Types of logs (mod value)
2134 	 * 1 = dsack_persists reduced by 1 via T-O or fast recovery exit.
2135 	 * 2 = a dsack round begins, persist is reset to 16.
2136 	 * 3 = a dsack round ends
2137 	 * 4 = Dsack option increases rack rtt flex5 is the srtt input, flex6 is thresh
2138 	 * 5 = Socket option set changing the control flags rc_rack_tmr_std_based, rc_rack_use_dsack
2139 	 * 6 = Final rack rtt, flex4 is srtt and flex6 is final limited thresh.
2140 	 */
2141 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2142 		union tcp_log_stackspecific log;
2143 		struct timeval tv;
2144 
2145 		memset(&log, 0, sizeof(log));
2146 		log.u_bbr.flex1 = rack->rc_rack_tmr_std_based;
2147 		log.u_bbr.flex1 <<= 1;
2148 		log.u_bbr.flex1 |= rack->rc_rack_use_dsack;
2149 		log.u_bbr.flex1 <<= 1;
2150 		log.u_bbr.flex1 |= rack->rc_dsack_round_seen;
2151 		log.u_bbr.flex2 = rack->r_ctl.dsack_round_end;
2152 		log.u_bbr.flex3 = rack->r_ctl.num_dsack;
2153 		log.u_bbr.flex4 = flex4;
2154 		log.u_bbr.flex5 = flex5;
2155 		log.u_bbr.flex6 = flex6;
2156 		log.u_bbr.flex7 = rack->r_ctl.dsack_persist;
2157 		log.u_bbr.flex8 = mod;
2158 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2159 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2160 		    &rack->rc_inp->inp_socket->so_rcv,
2161 		    &rack->rc_inp->inp_socket->so_snd,
2162 		    RACK_DSACK_HANDLING, 0,
2163 		    0, &log, false, &tv);
2164 	}
2165 }
2166 
2167 static void
2168 rack_log_hdwr_pacing(struct tcp_rack *rack,
2169 		     uint64_t rate, uint64_t hw_rate, int line,
2170 		     int error, uint16_t mod)
2171 {
2172 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2173 		union tcp_log_stackspecific log;
2174 		struct timeval tv;
2175 		const struct ifnet *ifp;
2176 
2177 		memset(&log, 0, sizeof(log));
2178 		log.u_bbr.flex1 = ((hw_rate >> 32) & 0x00000000ffffffff);
2179 		log.u_bbr.flex2 = (hw_rate & 0x00000000ffffffff);
2180 		if (rack->r_ctl.crte) {
2181 			ifp = rack->r_ctl.crte->ptbl->rs_ifp;
2182 		} else if (rack->rc_inp->inp_route.ro_nh &&
2183 			   rack->rc_inp->inp_route.ro_nh->nh_ifp) {
2184 			ifp = rack->rc_inp->inp_route.ro_nh->nh_ifp;
2185 		} else
2186 			ifp = NULL;
2187 		if (ifp) {
2188 			log.u_bbr.flex3 = (((uint64_t)ifp  >> 32) & 0x00000000ffffffff);
2189 			log.u_bbr.flex4 = ((uint64_t)ifp & 0x00000000ffffffff);
2190 		}
2191 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2192 		log.u_bbr.bw_inuse = rate;
2193 		log.u_bbr.flex5 = line;
2194 		log.u_bbr.flex6 = error;
2195 		log.u_bbr.flex7 = mod;
2196 		log.u_bbr.applimited = rack->r_ctl.rc_pace_max_segs;
2197 		log.u_bbr.flex8 = rack->use_fixed_rate;
2198 		log.u_bbr.flex8 <<= 1;
2199 		log.u_bbr.flex8 |= rack->rack_hdrw_pacing;
2200 		log.u_bbr.pkts_out = rack->rc_tp->t_maxseg;
2201 		log.u_bbr.delRate = rack->r_ctl.crte_prev_rate;
2202 		if (rack->r_ctl.crte)
2203 			log.u_bbr.cur_del_rate = rack->r_ctl.crte->rate;
2204 		else
2205 			log.u_bbr.cur_del_rate = 0;
2206 		log.u_bbr.rttProp = rack->r_ctl.last_hw_bw_req;
2207 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2208 		    &rack->rc_inp->inp_socket->so_rcv,
2209 		    &rack->rc_inp->inp_socket->so_snd,
2210 		    BBR_LOG_HDWR_PACE, 0,
2211 		    0, &log, false, &tv);
2212 	}
2213 }
2214 
2215 static uint64_t
2216 rack_get_output_bw(struct tcp_rack *rack, uint64_t bw, struct rack_sendmap *rsm, int *capped)
2217 {
2218 	/*
2219 	 * We allow rack_per_of_gp_xx to dictate our bw rate we want.
2220 	 */
2221 	uint64_t bw_est, high_rate;
2222 	uint64_t gain;
2223 
2224 	gain = (uint64_t)rack_get_output_gain(rack, rsm);
2225 	bw_est = bw * gain;
2226 	bw_est /= (uint64_t)100;
2227 	/* Never fall below the minimum (def 64kbps) */
2228 	if (bw_est < RACK_MIN_BW)
2229 		bw_est = RACK_MIN_BW;
2230 	if (rack->r_rack_hw_rate_caps) {
2231 		/* Rate caps are in place */
2232 		if (rack->r_ctl.crte != NULL) {
2233 			/* We have a hdwr rate already */
2234 			high_rate = tcp_hw_highest_rate(rack->r_ctl.crte);
2235 			if (bw_est >= high_rate) {
2236 				/* We are capping bw at the highest rate table entry */
2237 				rack_log_hdwr_pacing(rack,
2238 						     bw_est, high_rate, __LINE__,
2239 						     0, 3);
2240 				bw_est = high_rate;
2241 				if (capped)
2242 					*capped = 1;
2243 			}
2244 		} else if ((rack->rack_hdrw_pacing == 0) &&
2245 			   (rack->rack_hdw_pace_ena) &&
2246 			   (rack->rack_attempt_hdwr_pace == 0) &&
2247 			   (rack->rc_inp->inp_route.ro_nh != NULL) &&
2248 			   (rack->rc_inp->inp_route.ro_nh->nh_ifp != NULL)) {
2249 			/*
2250 			 * Special case, we have not yet attempted hardware
2251 			 * pacing, and yet we may, when we do, find out if we are
2252 			 * above the highest rate. We need to know the maxbw for the interface
2253 			 * in question (if it supports ratelimiting). We get back
2254 			 * a 0, if the interface is not found in the RL lists.
2255 			 */
2256 			high_rate = tcp_hw_highest_rate_ifp(rack->rc_inp->inp_route.ro_nh->nh_ifp, rack->rc_inp);
2257 			if (high_rate) {
2258 				/* Yep, we have a rate is it above this rate? */
2259 				if (bw_est > high_rate) {
2260 					bw_est = high_rate;
2261 					if (capped)
2262 						*capped = 1;
2263 				}
2264 			}
2265 		}
2266 	}
2267 	return (bw_est);
2268 }
2269 
2270 static void
2271 rack_log_retran_reason(struct tcp_rack *rack, struct rack_sendmap *rsm, uint32_t tsused, uint32_t thresh, int mod)
2272 {
2273 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2274 		union tcp_log_stackspecific log;
2275 		struct timeval tv;
2276 
2277 		if ((mod != 1) && (rack_verbose_logging == 0)) {
2278 			/*
2279 			 * We get 3 values currently for mod
2280 			 * 1 - We are retransmitting and this tells the reason.
2281 			 * 2 - We are clearing a dup-ack count.
2282 			 * 3 - We are incrementing a dup-ack count.
2283 			 *
2284 			 * The clear/increment are only logged
2285 			 * if you have BBverbose on.
2286 			 */
2287 			return;
2288 		}
2289 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2290 		log.u_bbr.flex1 = tsused;
2291 		log.u_bbr.flex2 = thresh;
2292 		log.u_bbr.flex3 = rsm->r_flags;
2293 		log.u_bbr.flex4 = rsm->r_dupack;
2294 		log.u_bbr.flex5 = rsm->r_start;
2295 		log.u_bbr.flex6 = rsm->r_end;
2296 		log.u_bbr.flex8 = mod;
2297 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2298 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
2299 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2300 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2301 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2302 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2303 		log.u_bbr.pacing_gain = rack->r_must_retran;
2304 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2305 		    &rack->rc_inp->inp_socket->so_rcv,
2306 		    &rack->rc_inp->inp_socket->so_snd,
2307 		    BBR_LOG_SETTINGS_CHG, 0,
2308 		    0, &log, false, &tv);
2309 	}
2310 }
2311 
2312 static void
2313 rack_log_to_start(struct tcp_rack *rack, uint32_t cts, uint32_t to, int32_t slot, uint8_t which)
2314 {
2315 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2316 		union tcp_log_stackspecific log;
2317 		struct timeval tv;
2318 
2319 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2320 		log.u_bbr.flex1 = rack->rc_tp->t_srtt;
2321 		log.u_bbr.flex2 = to;
2322 		log.u_bbr.flex3 = rack->r_ctl.rc_hpts_flags;
2323 		log.u_bbr.flex4 = slot;
2324 		log.u_bbr.flex5 = rack->rc_inp->inp_hptsslot;
2325 		log.u_bbr.flex6 = rack->rc_tp->t_rxtcur;
2326 		log.u_bbr.flex7 = rack->rc_in_persist;
2327 		log.u_bbr.flex8 = which;
2328 		if (rack->rack_no_prr)
2329 			log.u_bbr.pkts_out = 0;
2330 		else
2331 			log.u_bbr.pkts_out = rack->r_ctl.rc_prr_sndcnt;
2332 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2333 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
2334 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2335 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2336 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2337 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2338 		log.u_bbr.pacing_gain = rack->r_must_retran;
2339 		log.u_bbr.lt_epoch = rack->rc_tp->t_rxtshift;
2340 		log.u_bbr.lost = rack_rto_min;
2341 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2342 		    &rack->rc_inp->inp_socket->so_rcv,
2343 		    &rack->rc_inp->inp_socket->so_snd,
2344 		    BBR_LOG_TIMERSTAR, 0,
2345 		    0, &log, false, &tv);
2346 	}
2347 }
2348 
2349 static void
2350 rack_log_to_event(struct tcp_rack *rack, int32_t to_num, struct rack_sendmap *rsm)
2351 {
2352 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2353 		union tcp_log_stackspecific log;
2354 		struct timeval tv;
2355 
2356 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2357 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2358 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
2359 		log.u_bbr.flex8 = to_num;
2360 		log.u_bbr.flex1 = rack->r_ctl.rc_rack_min_rtt;
2361 		log.u_bbr.flex2 = rack->rc_rack_rtt;
2362 		if (rsm == NULL)
2363 			log.u_bbr.flex3 = 0;
2364 		else
2365 			log.u_bbr.flex3 = rsm->r_end - rsm->r_start;
2366 		if (rack->rack_no_prr)
2367 			log.u_bbr.flex5 = 0;
2368 		else
2369 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
2370 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2371 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2372 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2373 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2374 		log.u_bbr.pacing_gain = rack->r_must_retran;
2375 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2376 		    &rack->rc_inp->inp_socket->so_rcv,
2377 		    &rack->rc_inp->inp_socket->so_snd,
2378 		    BBR_LOG_RTO, 0,
2379 		    0, &log, false, &tv);
2380 	}
2381 }
2382 
2383 static void
2384 rack_log_map_chg(struct tcpcb *tp, struct tcp_rack *rack,
2385 		 struct rack_sendmap *prev,
2386 		 struct rack_sendmap *rsm,
2387 		 struct rack_sendmap *next,
2388 		 int flag, uint32_t th_ack, int line)
2389 {
2390 	if (rack_verbose_logging && (tp->t_logstate != TCP_LOG_STATE_OFF)) {
2391 		union tcp_log_stackspecific log;
2392 		struct timeval tv;
2393 
2394 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2395 		log.u_bbr.flex8 = flag;
2396 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2397 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
2398 		log.u_bbr.cur_del_rate = (uint64_t)prev;
2399 		log.u_bbr.delRate = (uint64_t)rsm;
2400 		log.u_bbr.rttProp = (uint64_t)next;
2401 		log.u_bbr.flex7 = 0;
2402 		if (prev) {
2403 			log.u_bbr.flex1 = prev->r_start;
2404 			log.u_bbr.flex2 = prev->r_end;
2405 			log.u_bbr.flex7 |= 0x4;
2406 		}
2407 		if (rsm) {
2408 			log.u_bbr.flex3 = rsm->r_start;
2409 			log.u_bbr.flex4 = rsm->r_end;
2410 			log.u_bbr.flex7 |= 0x2;
2411 		}
2412 		if (next) {
2413 			log.u_bbr.flex5 = next->r_start;
2414 			log.u_bbr.flex6 = next->r_end;
2415 			log.u_bbr.flex7 |= 0x1;
2416 		}
2417 		log.u_bbr.applimited = line;
2418 		log.u_bbr.pkts_out = th_ack;
2419 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2420 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2421 		if (rack->rack_no_prr)
2422 			log.u_bbr.lost = 0;
2423 		else
2424 			log.u_bbr.lost = rack->r_ctl.rc_prr_sndcnt;
2425 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2426 		    &rack->rc_inp->inp_socket->so_rcv,
2427 		    &rack->rc_inp->inp_socket->so_snd,
2428 		    TCP_LOG_MAPCHG, 0,
2429 		    0, &log, false, &tv);
2430 	}
2431 }
2432 
2433 static void
2434 rack_log_rtt_upd(struct tcpcb *tp, struct tcp_rack *rack, uint32_t t, uint32_t len,
2435 		 struct rack_sendmap *rsm, int conf)
2436 {
2437 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
2438 		union tcp_log_stackspecific log;
2439 		struct timeval tv;
2440 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2441 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2442 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
2443 		log.u_bbr.flex1 = t;
2444 		log.u_bbr.flex2 = len;
2445 		log.u_bbr.flex3 = rack->r_ctl.rc_rack_min_rtt;
2446 		log.u_bbr.flex4 = rack->r_ctl.rack_rs.rs_rtt_lowest;
2447 		log.u_bbr.flex5 = rack->r_ctl.rack_rs.rs_rtt_highest;
2448 		log.u_bbr.flex6 = rack->r_ctl.rack_rs.rs_us_rtrcnt;
2449 		log.u_bbr.flex7 = conf;
2450 		log.u_bbr.rttProp = (uint64_t)rack->r_ctl.rack_rs.rs_rtt_tot;
2451 		log.u_bbr.flex8 = rack->r_ctl.rc_rate_sample_method;
2452 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2453 		log.u_bbr.delivered = rack->r_ctl.rack_rs.rs_us_rtrcnt;
2454 		log.u_bbr.pkts_out = rack->r_ctl.rack_rs.rs_flags;
2455 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2456 		if (rsm) {
2457 			log.u_bbr.pkt_epoch = rsm->r_start;
2458 			log.u_bbr.lost = rsm->r_end;
2459 			log.u_bbr.cwnd_gain = rsm->r_rtr_cnt;
2460 			/* We loose any upper of the 24 bits */
2461 			log.u_bbr.pacing_gain = (uint16_t)rsm->r_flags;
2462 		} else {
2463 			/* Its a SYN */
2464 			log.u_bbr.pkt_epoch = rack->rc_tp->iss;
2465 			log.u_bbr.lost = 0;
2466 			log.u_bbr.cwnd_gain = 0;
2467 			log.u_bbr.pacing_gain = 0;
2468 		}
2469 		/* Write out general bits of interest rrs here */
2470 		log.u_bbr.use_lt_bw = rack->rc_highly_buffered;
2471 		log.u_bbr.use_lt_bw <<= 1;
2472 		log.u_bbr.use_lt_bw |= rack->forced_ack;
2473 		log.u_bbr.use_lt_bw <<= 1;
2474 		log.u_bbr.use_lt_bw |= rack->rc_gp_dyn_mul;
2475 		log.u_bbr.use_lt_bw <<= 1;
2476 		log.u_bbr.use_lt_bw |= rack->in_probe_rtt;
2477 		log.u_bbr.use_lt_bw <<= 1;
2478 		log.u_bbr.use_lt_bw |= rack->measure_saw_probe_rtt;
2479 		log.u_bbr.use_lt_bw <<= 1;
2480 		log.u_bbr.use_lt_bw |= rack->app_limited_needs_set;
2481 		log.u_bbr.use_lt_bw <<= 1;
2482 		log.u_bbr.use_lt_bw |= rack->rc_gp_filled;
2483 		log.u_bbr.use_lt_bw <<= 1;
2484 		log.u_bbr.use_lt_bw |= rack->rc_dragged_bottom;
2485 		log.u_bbr.applimited = rack->r_ctl.rc_target_probertt_flight;
2486 		log.u_bbr.epoch = rack->r_ctl.rc_time_probertt_starts;
2487 		log.u_bbr.lt_epoch = rack->r_ctl.rc_time_probertt_entered;
2488 		log.u_bbr.cur_del_rate = rack->r_ctl.rc_lower_rtt_us_cts;
2489 		log.u_bbr.delRate = rack->r_ctl.rc_gp_srtt;
2490 		log.u_bbr.bw_inuse = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
2491 		log.u_bbr.bw_inuse <<= 32;
2492 		if (rsm)
2493 			log.u_bbr.bw_inuse |= ((uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)]);
2494 		TCP_LOG_EVENTP(tp, NULL,
2495 		    &rack->rc_inp->inp_socket->so_rcv,
2496 		    &rack->rc_inp->inp_socket->so_snd,
2497 		    BBR_LOG_BBRRTT, 0,
2498 		    0, &log, false, &tv);
2499 
2500 
2501 	}
2502 }
2503 
2504 static void
2505 rack_log_rtt_sample(struct tcp_rack *rack, uint32_t rtt)
2506 {
2507 	/*
2508 	 * Log the rtt sample we are
2509 	 * applying to the srtt algorithm in
2510 	 * useconds.
2511 	 */
2512 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2513 		union tcp_log_stackspecific log;
2514 		struct timeval tv;
2515 
2516 		/* Convert our ms to a microsecond */
2517 		memset(&log, 0, sizeof(log));
2518 		log.u_bbr.flex1 = rtt;
2519 		log.u_bbr.flex2 = rack->r_ctl.ack_count;
2520 		log.u_bbr.flex3 = rack->r_ctl.sack_count;
2521 		log.u_bbr.flex4 = rack->r_ctl.sack_noextra_move;
2522 		log.u_bbr.flex5 = rack->r_ctl.sack_moved_extra;
2523 		log.u_bbr.flex6 = rack->rc_tp->t_rxtcur;
2524 		log.u_bbr.flex7 = 1;
2525 		log.u_bbr.flex8 = rack->sack_attack_disable;
2526 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2527 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2528 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2529 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2530 		log.u_bbr.pacing_gain = rack->r_must_retran;
2531 		/*
2532 		 * We capture in delRate the upper 32 bits as
2533 		 * the confidence level we had declared, and the
2534 		 * lower 32 bits as the actual RTT using the arrival
2535 		 * timestamp.
2536 		 */
2537 		log.u_bbr.delRate = rack->r_ctl.rack_rs.confidence;
2538 		log.u_bbr.delRate <<= 32;
2539 		log.u_bbr.delRate |= rack->r_ctl.rack_rs.rs_us_rtt;
2540 		/* Lets capture all the things that make up t_rtxcur */
2541 		log.u_bbr.applimited = rack_rto_min;
2542 		log.u_bbr.epoch = rack_rto_max;
2543 		log.u_bbr.lt_epoch = rack->r_ctl.timer_slop;
2544 		log.u_bbr.lost = rack_rto_min;
2545 		log.u_bbr.pkt_epoch = TICKS_2_USEC(tcp_rexmit_slop);
2546 		log.u_bbr.rttProp = RACK_REXMTVAL(rack->rc_tp);
2547 		log.u_bbr.bw_inuse = rack->r_ctl.act_rcv_time.tv_sec;
2548 		log.u_bbr.bw_inuse *= HPTS_USEC_IN_SEC;
2549 		log.u_bbr.bw_inuse += rack->r_ctl.act_rcv_time.tv_usec;
2550 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2551 		    &rack->rc_inp->inp_socket->so_rcv,
2552 		    &rack->rc_inp->inp_socket->so_snd,
2553 		    TCP_LOG_RTT, 0,
2554 		    0, &log, false, &tv);
2555 	}
2556 }
2557 
2558 static void
2559 rack_log_rtt_sample_calc(struct tcp_rack *rack, uint32_t rtt, uint32_t send_time, uint32_t ack_time, int where)
2560 {
2561 	if (rack_verbose_logging && (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2562 		union tcp_log_stackspecific log;
2563 		struct timeval tv;
2564 
2565 		/* Convert our ms to a microsecond */
2566 		memset(&log, 0, sizeof(log));
2567 		log.u_bbr.flex1 = rtt;
2568 		log.u_bbr.flex2 = send_time;
2569 		log.u_bbr.flex3 = ack_time;
2570 		log.u_bbr.flex4 = where;
2571 		log.u_bbr.flex7 = 2;
2572 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2573 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2574 		    &rack->rc_inp->inp_socket->so_rcv,
2575 		    &rack->rc_inp->inp_socket->so_snd,
2576 		    TCP_LOG_RTT, 0,
2577 		    0, &log, false, &tv);
2578 	}
2579 }
2580 
2581 
2582 
2583 static inline void
2584 rack_log_progress_event(struct tcp_rack *rack, struct tcpcb *tp, uint32_t tick,  int event, int line)
2585 {
2586 	if (rack_verbose_logging && (tp->t_logstate != TCP_LOG_STATE_OFF)) {
2587 		union tcp_log_stackspecific log;
2588 		struct timeval tv;
2589 
2590 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2591 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2592 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
2593 		log.u_bbr.flex1 = line;
2594 		log.u_bbr.flex2 = tick;
2595 		log.u_bbr.flex3 = tp->t_maxunacktime;
2596 		log.u_bbr.flex4 = tp->t_acktime;
2597 		log.u_bbr.flex8 = event;
2598 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2599 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2600 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2601 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2602 		log.u_bbr.pacing_gain = rack->r_must_retran;
2603 		TCP_LOG_EVENTP(tp, NULL,
2604 		    &rack->rc_inp->inp_socket->so_rcv,
2605 		    &rack->rc_inp->inp_socket->so_snd,
2606 		    BBR_LOG_PROGRESS, 0,
2607 		    0, &log, false, &tv);
2608 	}
2609 }
2610 
2611 static void
2612 rack_log_type_bbrsnd(struct tcp_rack *rack, uint32_t len, uint32_t slot, uint32_t cts, struct timeval *tv)
2613 {
2614 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2615 		union tcp_log_stackspecific log;
2616 
2617 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2618 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2619 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
2620 		log.u_bbr.flex1 = slot;
2621 		if (rack->rack_no_prr)
2622 			log.u_bbr.flex2 = 0;
2623 		else
2624 			log.u_bbr.flex2 = rack->r_ctl.rc_prr_sndcnt;
2625 		log.u_bbr.flex7 = (0x0000ffff & rack->r_ctl.rc_hpts_flags);
2626 		log.u_bbr.flex8 = rack->rc_in_persist;
2627 		log.u_bbr.timeStamp = cts;
2628 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2629 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2630 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2631 		log.u_bbr.pacing_gain = rack->r_must_retran;
2632 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2633 		    &rack->rc_inp->inp_socket->so_rcv,
2634 		    &rack->rc_inp->inp_socket->so_snd,
2635 		    BBR_LOG_BBRSND, 0,
2636 		    0, &log, false, tv);
2637 	}
2638 }
2639 
2640 static void
2641 rack_log_doseg_done(struct tcp_rack *rack, uint32_t cts, int32_t nxt_pkt, int32_t did_out, int way_out, int nsegs)
2642 {
2643 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2644 		union tcp_log_stackspecific log;
2645 		struct timeval tv;
2646 
2647 		memset(&log, 0, sizeof(log));
2648 		log.u_bbr.flex1 = did_out;
2649 		log.u_bbr.flex2 = nxt_pkt;
2650 		log.u_bbr.flex3 = way_out;
2651 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
2652 		if (rack->rack_no_prr)
2653 			log.u_bbr.flex5 = 0;
2654 		else
2655 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
2656 		log.u_bbr.flex6 = nsegs;
2657 		log.u_bbr.applimited = rack->r_ctl.rc_pace_min_segs;
2658 		log.u_bbr.flex7 = rack->rc_ack_can_sendout_data;	/* Do we have ack-can-send set */
2659 		log.u_bbr.flex7 <<= 1;
2660 		log.u_bbr.flex7 |= rack->r_fast_output;	/* is fast output primed */
2661 		log.u_bbr.flex7 <<= 1;
2662 		log.u_bbr.flex7 |= rack->r_wanted_output;	/* Do we want output */
2663 		log.u_bbr.flex8 = rack->rc_in_persist;
2664 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2665 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2666 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2667 		log.u_bbr.use_lt_bw = rack->r_ent_rec_ns;
2668 		log.u_bbr.use_lt_bw <<= 1;
2669 		log.u_bbr.use_lt_bw |= rack->r_might_revert;
2670 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2671 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2672 		log.u_bbr.pacing_gain = rack->r_must_retran;
2673 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2674 		    &rack->rc_inp->inp_socket->so_rcv,
2675 		    &rack->rc_inp->inp_socket->so_snd,
2676 		    BBR_LOG_DOSEG_DONE, 0,
2677 		    0, &log, false, &tv);
2678 	}
2679 }
2680 
2681 static void
2682 rack_log_type_pacing_sizes(struct tcpcb *tp, struct tcp_rack *rack, uint32_t arg1, uint32_t arg2, uint32_t arg3, uint8_t frm)
2683 {
2684 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
2685 		union tcp_log_stackspecific log;
2686 		struct timeval tv;
2687 		uint32_t cts;
2688 
2689 		memset(&log, 0, sizeof(log));
2690 		cts = tcp_get_usecs(&tv);
2691 		log.u_bbr.flex1 = rack->r_ctl.rc_pace_min_segs;
2692 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_max_segs;
2693 		log.u_bbr.flex4 = arg1;
2694 		log.u_bbr.flex5 = arg2;
2695 		log.u_bbr.flex6 = arg3;
2696 		log.u_bbr.flex8 = frm;
2697 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2698 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2699 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2700 		log.u_bbr.applimited = rack->r_ctl.rc_sacked;
2701 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2702 		log.u_bbr.pacing_gain = rack->r_must_retran;
2703 		TCP_LOG_EVENTP(tp, NULL,
2704 		    &tp->t_inpcb->inp_socket->so_rcv,
2705 		    &tp->t_inpcb->inp_socket->so_snd,
2706 		    TCP_HDWR_PACE_SIZE, 0,
2707 		    0, &log, false, &tv);
2708 	}
2709 }
2710 
2711 static void
2712 rack_log_type_just_return(struct tcp_rack *rack, uint32_t cts, uint32_t tlen, uint32_t slot,
2713 			  uint8_t hpts_calling, int reason, uint32_t cwnd_to_use)
2714 {
2715 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2716 		union tcp_log_stackspecific log;
2717 		struct timeval tv;
2718 
2719 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2720 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2721 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
2722 		log.u_bbr.flex1 = slot;
2723 		log.u_bbr.flex2 = rack->r_ctl.rc_hpts_flags;
2724 		log.u_bbr.flex4 = reason;
2725 		if (rack->rack_no_prr)
2726 			log.u_bbr.flex5 = 0;
2727 		else
2728 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
2729 		log.u_bbr.flex7 = hpts_calling;
2730 		log.u_bbr.flex8 = rack->rc_in_persist;
2731 		log.u_bbr.lt_epoch = cwnd_to_use;
2732 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2733 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2734 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2735 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2736 		log.u_bbr.pacing_gain = rack->r_must_retran;
2737 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2738 		    &rack->rc_inp->inp_socket->so_rcv,
2739 		    &rack->rc_inp->inp_socket->so_snd,
2740 		    BBR_LOG_JUSTRET, 0,
2741 		    tlen, &log, false, &tv);
2742 	}
2743 }
2744 
2745 static void
2746 rack_log_to_cancel(struct tcp_rack *rack, int32_t hpts_removed, int line, uint32_t us_cts,
2747 		   struct timeval *tv, uint32_t flags_on_entry)
2748 {
2749 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2750 		union tcp_log_stackspecific log;
2751 
2752 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2753 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2754 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
2755 		log.u_bbr.flex1 = line;
2756 		log.u_bbr.flex2 = rack->r_ctl.rc_last_output_to;
2757 		log.u_bbr.flex3 = flags_on_entry;
2758 		log.u_bbr.flex4 = us_cts;
2759 		if (rack->rack_no_prr)
2760 			log.u_bbr.flex5 = 0;
2761 		else
2762 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
2763 		log.u_bbr.flex6 = rack->rc_tp->t_rxtcur;
2764 		log.u_bbr.flex7 = hpts_removed;
2765 		log.u_bbr.flex8 = 1;
2766 		log.u_bbr.applimited = rack->r_ctl.rc_hpts_flags;
2767 		log.u_bbr.timeStamp = us_cts;
2768 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2769 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2770 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2771 		log.u_bbr.pacing_gain = rack->r_must_retran;
2772 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2773 		    &rack->rc_inp->inp_socket->so_rcv,
2774 		    &rack->rc_inp->inp_socket->so_snd,
2775 		    BBR_LOG_TIMERCANC, 0,
2776 		    0, &log, false, tv);
2777 	}
2778 }
2779 
2780 static void
2781 rack_log_alt_to_to_cancel(struct tcp_rack *rack,
2782 			  uint32_t flex1, uint32_t flex2,
2783 			  uint32_t flex3, uint32_t flex4,
2784 			  uint32_t flex5, uint32_t flex6,
2785 			  uint16_t flex7, uint8_t mod)
2786 {
2787 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2788 		union tcp_log_stackspecific log;
2789 		struct timeval tv;
2790 
2791 		if (mod == 1) {
2792 			/* No you can't use 1, its for the real to cancel */
2793 			return;
2794 		}
2795 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2796 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2797 		log.u_bbr.flex1 = flex1;
2798 		log.u_bbr.flex2 = flex2;
2799 		log.u_bbr.flex3 = flex3;
2800 		log.u_bbr.flex4 = flex4;
2801 		log.u_bbr.flex5 = flex5;
2802 		log.u_bbr.flex6 = flex6;
2803 		log.u_bbr.flex7 = flex7;
2804 		log.u_bbr.flex8 = mod;
2805 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2806 		    &rack->rc_inp->inp_socket->so_rcv,
2807 		    &rack->rc_inp->inp_socket->so_snd,
2808 		    BBR_LOG_TIMERCANC, 0,
2809 		    0, &log, false, &tv);
2810 	}
2811 }
2812 
2813 static void
2814 rack_log_to_processing(struct tcp_rack *rack, uint32_t cts, int32_t ret, int32_t timers)
2815 {
2816 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2817 		union tcp_log_stackspecific log;
2818 		struct timeval tv;
2819 
2820 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2821 		log.u_bbr.flex1 = timers;
2822 		log.u_bbr.flex2 = ret;
2823 		log.u_bbr.flex3 = rack->r_ctl.rc_timer_exp;
2824 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
2825 		log.u_bbr.flex5 = cts;
2826 		if (rack->rack_no_prr)
2827 			log.u_bbr.flex6 = 0;
2828 		else
2829 			log.u_bbr.flex6 = rack->r_ctl.rc_prr_sndcnt;
2830 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2831 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2832 		log.u_bbr.pacing_gain = rack->r_must_retran;
2833 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2834 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2835 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2836 		    &rack->rc_inp->inp_socket->so_rcv,
2837 		    &rack->rc_inp->inp_socket->so_snd,
2838 		    BBR_LOG_TO_PROCESS, 0,
2839 		    0, &log, false, &tv);
2840 	}
2841 }
2842 
2843 static void
2844 rack_log_to_prr(struct tcp_rack *rack, int frm, int orig_cwnd)
2845 {
2846 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2847 		union tcp_log_stackspecific log;
2848 		struct timeval tv;
2849 
2850 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2851 		log.u_bbr.flex1 = rack->r_ctl.rc_prr_out;
2852 		log.u_bbr.flex2 = rack->r_ctl.rc_prr_recovery_fs;
2853 		if (rack->rack_no_prr)
2854 			log.u_bbr.flex3 = 0;
2855 		else
2856 			log.u_bbr.flex3 = rack->r_ctl.rc_prr_sndcnt;
2857 		log.u_bbr.flex4 = rack->r_ctl.rc_prr_delivered;
2858 		log.u_bbr.flex5 = rack->r_ctl.rc_sacked;
2859 		log.u_bbr.flex6 = rack->r_ctl.rc_holes_rxt;
2860 		log.u_bbr.flex8 = frm;
2861 		log.u_bbr.pkts_out = orig_cwnd;
2862 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2863 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2864 		log.u_bbr.use_lt_bw = rack->r_ent_rec_ns;
2865 		log.u_bbr.use_lt_bw <<= 1;
2866 		log.u_bbr.use_lt_bw |= rack->r_might_revert;
2867 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2868 		    &rack->rc_inp->inp_socket->so_rcv,
2869 		    &rack->rc_inp->inp_socket->so_snd,
2870 		    BBR_LOG_BBRUPD, 0,
2871 		    0, &log, false, &tv);
2872 	}
2873 }
2874 
2875 #ifdef NETFLIX_EXP_DETECTION
2876 static void
2877 rack_log_sad(struct tcp_rack *rack, int event)
2878 {
2879 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2880 		union tcp_log_stackspecific log;
2881 		struct timeval tv;
2882 
2883 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2884 		log.u_bbr.flex1 = rack->r_ctl.sack_count;
2885 		log.u_bbr.flex2 = rack->r_ctl.ack_count;
2886 		log.u_bbr.flex3 = rack->r_ctl.sack_moved_extra;
2887 		log.u_bbr.flex4 = rack->r_ctl.sack_noextra_move;
2888 		log.u_bbr.flex5 = rack->r_ctl.rc_num_maps_alloced;
2889 		log.u_bbr.flex6 = tcp_sack_to_ack_thresh;
2890 		log.u_bbr.pkts_out = tcp_sack_to_move_thresh;
2891 		log.u_bbr.lt_epoch = (tcp_force_detection << 8);
2892 		log.u_bbr.lt_epoch |= rack->do_detection;
2893 		log.u_bbr.applimited = tcp_map_minimum;
2894 		log.u_bbr.flex7 = rack->sack_attack_disable;
2895 		log.u_bbr.flex8 = event;
2896 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2897 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2898 		log.u_bbr.delivered = tcp_sad_decay_val;
2899 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2900 		    &rack->rc_inp->inp_socket->so_rcv,
2901 		    &rack->rc_inp->inp_socket->so_snd,
2902 		    TCP_SAD_DETECTION, 0,
2903 		    0, &log, false, &tv);
2904 	}
2905 }
2906 #endif
2907 
2908 static void
2909 rack_counter_destroy(void)
2910 {
2911 	int i;
2912 
2913 	counter_u64_free(rack_fto_send);
2914 	counter_u64_free(rack_fto_rsm_send);
2915 	counter_u64_free(rack_nfto_resend);
2916 	counter_u64_free(rack_hw_pace_init_fail);
2917 	counter_u64_free(rack_hw_pace_lost);
2918 	counter_u64_free(rack_non_fto_send);
2919 	counter_u64_free(rack_extended_rfo);
2920 	counter_u64_free(rack_ack_total);
2921 	counter_u64_free(rack_express_sack);
2922 	counter_u64_free(rack_sack_total);
2923 	counter_u64_free(rack_move_none);
2924 	counter_u64_free(rack_move_some);
2925 	counter_u64_free(rack_sack_attacks_detected);
2926 	counter_u64_free(rack_sack_attacks_reversed);
2927 	counter_u64_free(rack_sack_used_next_merge);
2928 	counter_u64_free(rack_sack_used_prev_merge);
2929 	counter_u64_free(rack_badfr);
2930 	counter_u64_free(rack_badfr_bytes);
2931 	counter_u64_free(rack_rtm_prr_retran);
2932 	counter_u64_free(rack_rtm_prr_newdata);
2933 	counter_u64_free(rack_timestamp_mismatch);
2934 	counter_u64_free(rack_find_high);
2935 	counter_u64_free(rack_reorder_seen);
2936 	counter_u64_free(rack_tlp_tot);
2937 	counter_u64_free(rack_tlp_newdata);
2938 	counter_u64_free(rack_tlp_retran);
2939 	counter_u64_free(rack_tlp_retran_bytes);
2940 	counter_u64_free(rack_tlp_retran_fail);
2941 	counter_u64_free(rack_to_tot);
2942 	counter_u64_free(rack_to_arm_rack);
2943 	counter_u64_free(rack_to_arm_tlp);
2944 	counter_u64_free(rack_calc_zero);
2945 	counter_u64_free(rack_calc_nonzero);
2946 	counter_u64_free(rack_paced_segments);
2947 	counter_u64_free(rack_unpaced_segments);
2948 	counter_u64_free(rack_saw_enobuf);
2949 	counter_u64_free(rack_saw_enobuf_hw);
2950 	counter_u64_free(rack_saw_enetunreach);
2951 	counter_u64_free(rack_hot_alloc);
2952 	counter_u64_free(rack_to_alloc);
2953 	counter_u64_free(rack_to_alloc_hard);
2954 	counter_u64_free(rack_to_alloc_emerg);
2955 	counter_u64_free(rack_to_alloc_limited);
2956 	counter_u64_free(rack_alloc_limited_conns);
2957 	counter_u64_free(rack_split_limited);
2958 	for (i = 0; i < MAX_NUM_OF_CNTS; i++) {
2959 		counter_u64_free(rack_proc_comp_ack[i]);
2960 	}
2961 	counter_u64_free(rack_multi_single_eq);
2962 	counter_u64_free(rack_proc_non_comp_ack);
2963 	counter_u64_free(rack_sack_proc_all);
2964 	counter_u64_free(rack_sack_proc_restart);
2965 	counter_u64_free(rack_sack_proc_short);
2966 	counter_u64_free(rack_enter_tlp_calc);
2967 	counter_u64_free(rack_used_tlpmethod);
2968 	counter_u64_free(rack_used_tlpmethod2);
2969 	counter_u64_free(rack_sack_skipped_acked);
2970 	counter_u64_free(rack_sack_splits);
2971 	counter_u64_free(rack_progress_drops);
2972 	counter_u64_free(rack_input_idle_reduces);
2973 	counter_u64_free(rack_collapsed_win);
2974 	counter_u64_free(rack_tlp_does_nada);
2975 	counter_u64_free(rack_try_scwnd);
2976 	counter_u64_free(rack_per_timer_hole);
2977 	counter_u64_free(rack_large_ackcmp);
2978 	counter_u64_free(rack_small_ackcmp);
2979 	counter_u64_free(rack_persists_sends);
2980 	counter_u64_free(rack_persists_acks);
2981 	counter_u64_free(rack_persists_loss);
2982 	counter_u64_free(rack_persists_lost_ends);
2983 #ifdef INVARIANTS
2984 	counter_u64_free(rack_adjust_map_bw);
2985 #endif
2986 	COUNTER_ARRAY_FREE(rack_out_size, TCP_MSS_ACCT_SIZE);
2987 	COUNTER_ARRAY_FREE(rack_opts_arry, RACK_OPTS_SIZE);
2988 }
2989 
2990 static struct rack_sendmap *
2991 rack_alloc(struct tcp_rack *rack)
2992 {
2993 	struct rack_sendmap *rsm;
2994 
2995 	/*
2996 	 * First get the top of the list it in
2997 	 * theory is the "hottest" rsm we have,
2998 	 * possibly just freed by ack processing.
2999 	 */
3000 	if (rack->rc_free_cnt > rack_free_cache) {
3001 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
3002 		TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_tnext);
3003 		counter_u64_add(rack_hot_alloc, 1);
3004 		rack->rc_free_cnt--;
3005 		return (rsm);
3006 	}
3007 	/*
3008 	 * Once we get under our free cache we probably
3009 	 * no longer have a "hot" one available. Lets
3010 	 * get one from UMA.
3011 	 */
3012 	rsm = uma_zalloc(rack_zone, M_NOWAIT);
3013 	if (rsm) {
3014 		rack->r_ctl.rc_num_maps_alloced++;
3015 		counter_u64_add(rack_to_alloc, 1);
3016 		return (rsm);
3017 	}
3018 	/*
3019 	 * Dig in to our aux rsm's (the last two) since
3020 	 * UMA failed to get us one.
3021 	 */
3022 	if (rack->rc_free_cnt) {
3023 		counter_u64_add(rack_to_alloc_emerg, 1);
3024 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
3025 		TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_tnext);
3026 		rack->rc_free_cnt--;
3027 		return (rsm);
3028 	}
3029 	return (NULL);
3030 }
3031 
3032 static struct rack_sendmap *
3033 rack_alloc_full_limit(struct tcp_rack *rack)
3034 {
3035 	if ((V_tcp_map_entries_limit > 0) &&
3036 	    (rack->do_detection == 0) &&
3037 	    (rack->r_ctl.rc_num_maps_alloced >= V_tcp_map_entries_limit)) {
3038 		counter_u64_add(rack_to_alloc_limited, 1);
3039 		if (!rack->alloc_limit_reported) {
3040 			rack->alloc_limit_reported = 1;
3041 			counter_u64_add(rack_alloc_limited_conns, 1);
3042 		}
3043 		return (NULL);
3044 	}
3045 	return (rack_alloc(rack));
3046 }
3047 
3048 /* wrapper to allocate a sendmap entry, subject to a specific limit */
3049 static struct rack_sendmap *
3050 rack_alloc_limit(struct tcp_rack *rack, uint8_t limit_type)
3051 {
3052 	struct rack_sendmap *rsm;
3053 
3054 	if (limit_type) {
3055 		/* currently there is only one limit type */
3056 		if (V_tcp_map_split_limit > 0 &&
3057 		    (rack->do_detection == 0) &&
3058 		    rack->r_ctl.rc_num_split_allocs >= V_tcp_map_split_limit) {
3059 			counter_u64_add(rack_split_limited, 1);
3060 			if (!rack->alloc_limit_reported) {
3061 				rack->alloc_limit_reported = 1;
3062 				counter_u64_add(rack_alloc_limited_conns, 1);
3063 			}
3064 			return (NULL);
3065 		}
3066 	}
3067 
3068 	/* allocate and mark in the limit type, if set */
3069 	rsm = rack_alloc(rack);
3070 	if (rsm != NULL && limit_type) {
3071 		rsm->r_limit_type = limit_type;
3072 		rack->r_ctl.rc_num_split_allocs++;
3073 	}
3074 	return (rsm);
3075 }
3076 
3077 static void
3078 rack_free(struct tcp_rack *rack, struct rack_sendmap *rsm)
3079 {
3080 	if (rsm->r_flags & RACK_APP_LIMITED) {
3081 		if (rack->r_ctl.rc_app_limited_cnt > 0) {
3082 			rack->r_ctl.rc_app_limited_cnt--;
3083 		}
3084 	}
3085 	if (rsm->r_limit_type) {
3086 		/* currently there is only one limit type */
3087 		rack->r_ctl.rc_num_split_allocs--;
3088 	}
3089 	if (rsm == rack->r_ctl.rc_first_appl) {
3090 		if (rack->r_ctl.rc_app_limited_cnt == 0)
3091 			rack->r_ctl.rc_first_appl = NULL;
3092 		else {
3093 			/* Follow the next one out */
3094 			struct rack_sendmap fe;
3095 
3096 			fe.r_start = rsm->r_nseq_appl;
3097 			rack->r_ctl.rc_first_appl = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
3098 		}
3099 	}
3100 	if (rsm == rack->r_ctl.rc_resend)
3101 		rack->r_ctl.rc_resend = NULL;
3102 	if (rsm == rack->r_ctl.rc_rsm_at_retran)
3103 		rack->r_ctl.rc_rsm_at_retran = NULL;
3104 	if (rsm == rack->r_ctl.rc_end_appl)
3105 		rack->r_ctl.rc_end_appl = NULL;
3106 	if (rack->r_ctl.rc_tlpsend == rsm)
3107 		rack->r_ctl.rc_tlpsend = NULL;
3108 	if (rack->r_ctl.rc_sacklast == rsm)
3109 		rack->r_ctl.rc_sacklast = NULL;
3110 	memset(rsm, 0, sizeof(struct rack_sendmap));
3111 	TAILQ_INSERT_HEAD(&rack->r_ctl.rc_free, rsm, r_tnext);
3112 	rack->rc_free_cnt++;
3113 }
3114 
3115 static void
3116 rack_free_trim(struct tcp_rack *rack)
3117 {
3118 	struct rack_sendmap *rsm;
3119 
3120 	/*
3121 	 * Free up all the tail entries until
3122 	 * we get our list down to the limit.
3123 	 */
3124 	while (rack->rc_free_cnt > rack_free_cache) {
3125 		rsm = TAILQ_LAST(&rack->r_ctl.rc_free, rack_head);
3126 		TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_tnext);
3127 		rack->rc_free_cnt--;
3128 		uma_zfree(rack_zone, rsm);
3129 	}
3130 }
3131 
3132 
3133 static uint32_t
3134 rack_get_measure_window(struct tcpcb *tp, struct tcp_rack *rack)
3135 {
3136 	uint64_t srtt, bw, len, tim;
3137 	uint32_t segsiz, def_len, minl;
3138 
3139 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
3140 	def_len = rack_def_data_window * segsiz;
3141 	if (rack->rc_gp_filled == 0) {
3142 		/*
3143 		 * We have no measurement (IW is in flight?) so
3144 		 * we can only guess using our data_window sysctl
3145 		 * value (usually 20MSS).
3146 		 */
3147 		return (def_len);
3148 	}
3149 	/*
3150 	 * Now we have a number of factors to consider.
3151 	 *
3152 	 * 1) We have a desired BDP which is usually
3153 	 *    at least 2.
3154 	 * 2) We have a minimum number of rtt's usually 1 SRTT
3155 	 *    but we allow it too to be more.
3156 	 * 3) We want to make sure a measurement last N useconds (if
3157 	 *    we have set rack_min_measure_usec.
3158 	 *
3159 	 * We handle the first concern here by trying to create a data
3160 	 * window of max(rack_def_data_window, DesiredBDP). The
3161 	 * second concern we handle in not letting the measurement
3162 	 * window end normally until at least the required SRTT's
3163 	 * have gone by which is done further below in
3164 	 * rack_enough_for_measurement(). Finally the third concern
3165 	 * we also handle here by calculating how long that time
3166 	 * would take at the current BW and then return the
3167 	 * max of our first calculation and that length. Note
3168 	 * that if rack_min_measure_usec is 0, we don't deal
3169 	 * with concern 3. Also for both Concern 1 and 3 an
3170 	 * application limited period could end the measurement
3171 	 * earlier.
3172 	 *
3173 	 * So lets calculate the BDP with the "known" b/w using
3174 	 * the SRTT has our rtt and then multiply it by the
3175 	 * goal.
3176 	 */
3177 	bw = rack_get_bw(rack);
3178 	srtt = (uint64_t)tp->t_srtt;
3179 	len = bw * srtt;
3180 	len /= (uint64_t)HPTS_USEC_IN_SEC;
3181 	len *= max(1, rack_goal_bdp);
3182 	/* Now we need to round up to the nearest MSS */
3183 	len = roundup(len, segsiz);
3184 	if (rack_min_measure_usec) {
3185 		/* Now calculate our min length for this b/w */
3186 		tim = rack_min_measure_usec;
3187 		minl = (tim * bw) / (uint64_t)HPTS_USEC_IN_SEC;
3188 		if (minl == 0)
3189 			minl = 1;
3190 		minl = roundup(minl, segsiz);
3191 		if (len < minl)
3192 			len = minl;
3193 	}
3194 	/*
3195 	 * Now if we have a very small window we want
3196 	 * to attempt to get the window that is
3197 	 * as small as possible. This happens on
3198 	 * low b/w connections and we don't want to
3199 	 * span huge numbers of rtt's between measurements.
3200 	 *
3201 	 * We basically include 2 over our "MIN window" so
3202 	 * that the measurement can be shortened (possibly) by
3203 	 * an ack'ed packet.
3204 	 */
3205 	if (len < def_len)
3206 		return (max((uint32_t)len, ((MIN_GP_WIN+2) * segsiz)));
3207 	else
3208 		return (max((uint32_t)len, def_len));
3209 
3210 }
3211 
3212 static int
3213 rack_enough_for_measurement(struct tcpcb *tp, struct tcp_rack *rack, tcp_seq th_ack, uint8_t *quality)
3214 {
3215 	uint32_t tim, srtts, segsiz;
3216 
3217 	/*
3218 	 * Has enough time passed for the GP measurement to be valid?
3219 	 */
3220 	if ((tp->snd_max == tp->snd_una) ||
3221 	    (th_ack == tp->snd_max)){
3222 		/* All is acked */
3223 		*quality = RACK_QUALITY_ALLACKED;
3224 		return (1);
3225 	}
3226 	if (SEQ_LT(th_ack, tp->gput_seq)) {
3227 		/* Not enough bytes yet */
3228 		return (0);
3229 	}
3230 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
3231 	if (SEQ_LT(th_ack, tp->gput_ack) &&
3232 	    ((th_ack - tp->gput_seq) < max(rc_init_window(rack), (MIN_GP_WIN * segsiz)))) {
3233 		/* Not enough bytes yet */
3234 		return (0);
3235 	}
3236 	if (rack->r_ctl.rc_first_appl &&
3237 	    (SEQ_GEQ(th_ack, rack->r_ctl.rc_first_appl->r_end))) {
3238 		/*
3239 		 * We are up to the app limited send point
3240 		 * we have to measure irrespective of the time..
3241 		 */
3242 		*quality = RACK_QUALITY_APPLIMITED;
3243 		return (1);
3244 	}
3245 	/* Now what about time? */
3246 	srtts = (rack->r_ctl.rc_gp_srtt * rack_min_srtts);
3247 	tim = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time) - tp->gput_ts;
3248 	if (tim >= srtts) {
3249 		*quality = RACK_QUALITY_HIGH;
3250 		return (1);
3251 	}
3252 	/* Nope not even a full SRTT has passed */
3253 	return (0);
3254 }
3255 
3256 static void
3257 rack_log_timely(struct tcp_rack *rack,
3258 		uint32_t logged, uint64_t cur_bw, uint64_t low_bnd,
3259 		uint64_t up_bnd, int line, uint8_t method)
3260 {
3261 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
3262 		union tcp_log_stackspecific log;
3263 		struct timeval tv;
3264 
3265 		memset(&log, 0, sizeof(log));
3266 		log.u_bbr.flex1 = logged;
3267 		log.u_bbr.flex2 = rack->rc_gp_timely_inc_cnt;
3268 		log.u_bbr.flex2 <<= 4;
3269 		log.u_bbr.flex2 |= rack->rc_gp_timely_dec_cnt;
3270 		log.u_bbr.flex2 <<= 4;
3271 		log.u_bbr.flex2 |= rack->rc_gp_incr;
3272 		log.u_bbr.flex2 <<= 4;
3273 		log.u_bbr.flex2 |= rack->rc_gp_bwred;
3274 		log.u_bbr.flex3 = rack->rc_gp_incr;
3275 		log.u_bbr.flex4 = rack->r_ctl.rack_per_of_gp_ss;
3276 		log.u_bbr.flex5 = rack->r_ctl.rack_per_of_gp_ca;
3277 		log.u_bbr.flex6 = rack->r_ctl.rack_per_of_gp_rec;
3278 		log.u_bbr.flex7 = rack->rc_gp_bwred;
3279 		log.u_bbr.flex8 = method;
3280 		log.u_bbr.cur_del_rate = cur_bw;
3281 		log.u_bbr.delRate = low_bnd;
3282 		log.u_bbr.bw_inuse = up_bnd;
3283 		log.u_bbr.rttProp = rack_get_bw(rack);
3284 		log.u_bbr.pkt_epoch = line;
3285 		log.u_bbr.pkts_out = rack->r_ctl.rc_rtt_diff;
3286 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
3287 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
3288 		log.u_bbr.epoch = rack->r_ctl.rc_gp_srtt;
3289 		log.u_bbr.lt_epoch = rack->r_ctl.rc_prev_gp_srtt;
3290 		log.u_bbr.cwnd_gain = rack->rc_dragged_bottom;
3291 		log.u_bbr.cwnd_gain <<= 1;
3292 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_rec;
3293 		log.u_bbr.cwnd_gain <<= 1;
3294 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ss;
3295 		log.u_bbr.cwnd_gain <<= 1;
3296 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ca;
3297 		log.u_bbr.lost = rack->r_ctl.rc_loss_count;
3298 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
3299 		    &rack->rc_inp->inp_socket->so_rcv,
3300 		    &rack->rc_inp->inp_socket->so_snd,
3301 		    TCP_TIMELY_WORK, 0,
3302 		    0, &log, false, &tv);
3303 	}
3304 }
3305 
3306 static int
3307 rack_bw_can_be_raised(struct tcp_rack *rack, uint64_t cur_bw, uint64_t last_bw_est, uint16_t mult)
3308 {
3309 	/*
3310 	 * Before we increase we need to know if
3311 	 * the estimate just made was less than
3312 	 * our pacing goal (i.e. (cur_bw * mult) > last_bw_est)
3313 	 *
3314 	 * If we already are pacing at a fast enough
3315 	 * rate to push us faster there is no sense of
3316 	 * increasing.
3317 	 *
3318 	 * We first caculate our actual pacing rate (ss or ca multipler
3319 	 * times our cur_bw).
3320 	 *
3321 	 * Then we take the last measured rate and multipy by our
3322 	 * maximum pacing overage to give us a max allowable rate.
3323 	 *
3324 	 * If our act_rate is smaller than our max_allowable rate
3325 	 * then we should increase. Else we should hold steady.
3326 	 *
3327 	 */
3328 	uint64_t act_rate, max_allow_rate;
3329 
3330 	if (rack_timely_no_stopping)
3331 		return (1);
3332 
3333 	if ((cur_bw == 0) || (last_bw_est == 0)) {
3334 		/*
3335 		 * Initial startup case or
3336 		 * everything is acked case.
3337 		 */
3338 		rack_log_timely(rack,  mult, cur_bw, 0, 0,
3339 				__LINE__, 9);
3340 		return (1);
3341 	}
3342 	if (mult <= 100) {
3343 		/*
3344 		 * We can always pace at or slightly above our rate.
3345 		 */
3346 		rack_log_timely(rack,  mult, cur_bw, 0, 0,
3347 				__LINE__, 9);
3348 		return (1);
3349 	}
3350 	act_rate = cur_bw * (uint64_t)mult;
3351 	act_rate /= 100;
3352 	max_allow_rate = last_bw_est * ((uint64_t)rack_max_per_above + (uint64_t)100);
3353 	max_allow_rate /= 100;
3354 	if (act_rate < max_allow_rate) {
3355 		/*
3356 		 * Here the rate we are actually pacing at
3357 		 * is smaller than 10% above our last measurement.
3358 		 * This means we are pacing below what we would
3359 		 * like to try to achieve (plus some wiggle room).
3360 		 */
3361 		rack_log_timely(rack,  mult, cur_bw, act_rate, max_allow_rate,
3362 				__LINE__, 9);
3363 		return (1);
3364 	} else {
3365 		/*
3366 		 * Here we are already pacing at least rack_max_per_above(10%)
3367 		 * what we are getting back. This indicates most likely
3368 		 * that we are being limited (cwnd/rwnd/app) and can't
3369 		 * get any more b/w. There is no sense of trying to
3370 		 * raise up the pacing rate its not speeding us up
3371 		 * and we already are pacing faster than we are getting.
3372 		 */
3373 		rack_log_timely(rack,  mult, cur_bw, act_rate, max_allow_rate,
3374 				__LINE__, 8);
3375 		return (0);
3376 	}
3377 }
3378 
3379 static void
3380 rack_validate_multipliers_at_or_above100(struct tcp_rack *rack)
3381 {
3382 	/*
3383 	 * When we drag bottom, we want to assure
3384 	 * that no multiplier is below 1.0, if so
3385 	 * we want to restore it to at least that.
3386 	 */
3387 	if (rack->r_ctl.rack_per_of_gp_rec  < 100) {
3388 		/* This is unlikely we usually do not touch recovery */
3389 		rack->r_ctl.rack_per_of_gp_rec = 100;
3390 	}
3391 	if (rack->r_ctl.rack_per_of_gp_ca < 100) {
3392 		rack->r_ctl.rack_per_of_gp_ca = 100;
3393 	}
3394 	if (rack->r_ctl.rack_per_of_gp_ss < 100) {
3395 		rack->r_ctl.rack_per_of_gp_ss = 100;
3396 	}
3397 }
3398 
3399 static void
3400 rack_validate_multipliers_at_or_below_100(struct tcp_rack *rack)
3401 {
3402 	if (rack->r_ctl.rack_per_of_gp_ca > 100) {
3403 		rack->r_ctl.rack_per_of_gp_ca = 100;
3404 	}
3405 	if (rack->r_ctl.rack_per_of_gp_ss > 100) {
3406 		rack->r_ctl.rack_per_of_gp_ss = 100;
3407 	}
3408 }
3409 
3410 static void
3411 rack_increase_bw_mul(struct tcp_rack *rack, int timely_says, uint64_t cur_bw, uint64_t last_bw_est, int override)
3412 {
3413 	int32_t  calc, logged, plus;
3414 
3415 	logged = 0;
3416 
3417 	if (override) {
3418 		/*
3419 		 * override is passed when we are
3420 		 * loosing b/w and making one last
3421 		 * gasp at trying to not loose out
3422 		 * to a new-reno flow.
3423 		 */
3424 		goto extra_boost;
3425 	}
3426 	/* In classic timely we boost by 5x if we have 5 increases in a row, lets not */
3427 	if (rack->rc_gp_incr &&
3428 	    ((rack->rc_gp_timely_inc_cnt + 1) >= RACK_TIMELY_CNT_BOOST)) {
3429 		/*
3430 		 * Reset and get 5 strokes more before the boost. Note
3431 		 * that the count is 0 based so we have to add one.
3432 		 */
3433 extra_boost:
3434 		plus = (uint32_t)rack_gp_increase_per * RACK_TIMELY_CNT_BOOST;
3435 		rack->rc_gp_timely_inc_cnt = 0;
3436 	} else
3437 		plus = (uint32_t)rack_gp_increase_per;
3438 	/* Must be at least 1% increase for true timely increases */
3439 	if ((plus < 1) &&
3440 	    ((rack->r_ctl.rc_rtt_diff <= 0) || (timely_says <= 0)))
3441 		plus = 1;
3442 	if (rack->rc_gp_saw_rec &&
3443 	    (rack->rc_gp_no_rec_chg == 0) &&
3444 	    rack_bw_can_be_raised(rack, cur_bw, last_bw_est,
3445 				  rack->r_ctl.rack_per_of_gp_rec)) {
3446 		/* We have been in recovery ding it too */
3447 		calc = rack->r_ctl.rack_per_of_gp_rec + plus;
3448 		if (calc > 0xffff)
3449 			calc = 0xffff;
3450 		logged |= 1;
3451 		rack->r_ctl.rack_per_of_gp_rec = (uint16_t)calc;
3452 		if (rack_per_upper_bound_ss &&
3453 		    (rack->rc_dragged_bottom == 0) &&
3454 		    (rack->r_ctl.rack_per_of_gp_rec > rack_per_upper_bound_ss))
3455 			rack->r_ctl.rack_per_of_gp_rec = rack_per_upper_bound_ss;
3456 	}
3457 	if (rack->rc_gp_saw_ca &&
3458 	    (rack->rc_gp_saw_ss == 0) &&
3459 	    rack_bw_can_be_raised(rack, cur_bw, last_bw_est,
3460 				  rack->r_ctl.rack_per_of_gp_ca)) {
3461 		/* In CA */
3462 		calc = rack->r_ctl.rack_per_of_gp_ca + plus;
3463 		if (calc > 0xffff)
3464 			calc = 0xffff;
3465 		logged |= 2;
3466 		rack->r_ctl.rack_per_of_gp_ca = (uint16_t)calc;
3467 		if (rack_per_upper_bound_ca &&
3468 		    (rack->rc_dragged_bottom == 0) &&
3469 		    (rack->r_ctl.rack_per_of_gp_ca > rack_per_upper_bound_ca))
3470 			rack->r_ctl.rack_per_of_gp_ca = rack_per_upper_bound_ca;
3471 	}
3472 	if (rack->rc_gp_saw_ss &&
3473 	    rack_bw_can_be_raised(rack, cur_bw, last_bw_est,
3474 				  rack->r_ctl.rack_per_of_gp_ss)) {
3475 		/* In SS */
3476 		calc = rack->r_ctl.rack_per_of_gp_ss + plus;
3477 		if (calc > 0xffff)
3478 			calc = 0xffff;
3479 		rack->r_ctl.rack_per_of_gp_ss = (uint16_t)calc;
3480 		if (rack_per_upper_bound_ss &&
3481 		    (rack->rc_dragged_bottom == 0) &&
3482 		    (rack->r_ctl.rack_per_of_gp_ss > rack_per_upper_bound_ss))
3483 			rack->r_ctl.rack_per_of_gp_ss = rack_per_upper_bound_ss;
3484 		logged |= 4;
3485 	}
3486 	if (logged &&
3487 	    (rack->rc_gp_incr == 0)){
3488 		/* Go into increment mode */
3489 		rack->rc_gp_incr = 1;
3490 		rack->rc_gp_timely_inc_cnt = 0;
3491 	}
3492 	if (rack->rc_gp_incr &&
3493 	    logged &&
3494 	    (rack->rc_gp_timely_inc_cnt < RACK_TIMELY_CNT_BOOST)) {
3495 		rack->rc_gp_timely_inc_cnt++;
3496 	}
3497 	rack_log_timely(rack,  logged, plus, 0, 0,
3498 			__LINE__, 1);
3499 }
3500 
3501 static uint32_t
3502 rack_get_decrease(struct tcp_rack *rack, uint32_t curper, int32_t rtt_diff)
3503 {
3504 	/*
3505 	 * norm_grad = rtt_diff / minrtt;
3506 	 * new_per = curper * (1 - B * norm_grad)
3507 	 *
3508 	 * B = rack_gp_decrease_per (default 10%)
3509 	 * rtt_dif = input var current rtt-diff
3510 	 * curper = input var current percentage
3511 	 * minrtt = from rack filter
3512 	 *
3513 	 */
3514 	uint64_t perf;
3515 
3516 	perf = (((uint64_t)curper * ((uint64_t)1000000 -
3517 		    ((uint64_t)rack_gp_decrease_per * (uint64_t)10000 *
3518 		     (((uint64_t)rtt_diff * (uint64_t)1000000)/
3519 		      (uint64_t)get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt)))/
3520 		     (uint64_t)1000000)) /
3521 		(uint64_t)1000000);
3522 	if (perf > curper) {
3523 		/* TSNH */
3524 		perf = curper - 1;
3525 	}
3526 	return ((uint32_t)perf);
3527 }
3528 
3529 static uint32_t
3530 rack_decrease_highrtt(struct tcp_rack *rack, uint32_t curper, uint32_t rtt)
3531 {
3532 	/*
3533 	 *                                   highrttthresh
3534 	 * result = curper * (1 - (B * ( 1 -  ------          ))
3535 	 *                                     gp_srtt
3536 	 *
3537 	 * B = rack_gp_decrease_per (default 10%)
3538 	 * highrttthresh = filter_min * rack_gp_rtt_maxmul
3539 	 */
3540 	uint64_t perf;
3541 	uint32_t highrttthresh;
3542 
3543 	highrttthresh = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_maxmul;
3544 
3545 	perf = (((uint64_t)curper * ((uint64_t)1000000 -
3546 				     ((uint64_t)rack_gp_decrease_per * ((uint64_t)1000000 -
3547 					((uint64_t)highrttthresh * (uint64_t)1000000) /
3548 						    (uint64_t)rtt)) / 100)) /(uint64_t)1000000);
3549 	return (perf);
3550 }
3551 
3552 static void
3553 rack_decrease_bw_mul(struct tcp_rack *rack, int timely_says, uint32_t rtt, int32_t rtt_diff)
3554 {
3555 	uint64_t logvar, logvar2, logvar3;
3556 	uint32_t logged, new_per, ss_red, ca_red, rec_red, alt, val;
3557 
3558 	if (rack->rc_gp_incr) {
3559 		/* Turn off increment counting */
3560 		rack->rc_gp_incr = 0;
3561 		rack->rc_gp_timely_inc_cnt = 0;
3562 	}
3563 	ss_red = ca_red = rec_red = 0;
3564 	logged = 0;
3565 	/* Calculate the reduction value */
3566 	if (rtt_diff < 0) {
3567 		rtt_diff *= -1;
3568 	}
3569 	/* Must be at least 1% reduction */
3570 	if (rack->rc_gp_saw_rec && (rack->rc_gp_no_rec_chg == 0)) {
3571 		/* We have been in recovery ding it too */
3572 		if (timely_says == 2) {
3573 			new_per = rack_decrease_highrtt(rack, rack->r_ctl.rack_per_of_gp_rec, rtt);
3574 			alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
3575 			if (alt < new_per)
3576 				val = alt;
3577 			else
3578 				val = new_per;
3579 		} else
3580 			 val = new_per = alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
3581 		if (rack->r_ctl.rack_per_of_gp_rec > val) {
3582 			rec_red = (rack->r_ctl.rack_per_of_gp_rec - val);
3583 			rack->r_ctl.rack_per_of_gp_rec = (uint16_t)val;
3584 		} else {
3585 			rack->r_ctl.rack_per_of_gp_rec = rack_per_lower_bound;
3586 			rec_red = 0;
3587 		}
3588 		if (rack_per_lower_bound > rack->r_ctl.rack_per_of_gp_rec)
3589 			rack->r_ctl.rack_per_of_gp_rec = rack_per_lower_bound;
3590 		logged |= 1;
3591 	}
3592 	if (rack->rc_gp_saw_ss) {
3593 		/* Sent in SS */
3594 		if (timely_says == 2) {
3595 			new_per = rack_decrease_highrtt(rack, rack->r_ctl.rack_per_of_gp_ss, rtt);
3596 			alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
3597 			if (alt < new_per)
3598 				val = alt;
3599 			else
3600 				val = new_per;
3601 		} else
3602 			val = new_per = alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_ss, rtt_diff);
3603 		if (rack->r_ctl.rack_per_of_gp_ss > new_per) {
3604 			ss_red = rack->r_ctl.rack_per_of_gp_ss - val;
3605 			rack->r_ctl.rack_per_of_gp_ss = (uint16_t)val;
3606 		} else {
3607 			ss_red = new_per;
3608 			rack->r_ctl.rack_per_of_gp_ss = rack_per_lower_bound;
3609 			logvar = new_per;
3610 			logvar <<= 32;
3611 			logvar |= alt;
3612 			logvar2 = (uint32_t)rtt;
3613 			logvar2 <<= 32;
3614 			logvar2 |= (uint32_t)rtt_diff;
3615 			logvar3 = rack_gp_rtt_maxmul;
3616 			logvar3 <<= 32;
3617 			logvar3 |= get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
3618 			rack_log_timely(rack, timely_says,
3619 					logvar2, logvar3,
3620 					logvar, __LINE__, 10);
3621 		}
3622 		if (rack_per_lower_bound > rack->r_ctl.rack_per_of_gp_ss)
3623 			rack->r_ctl.rack_per_of_gp_ss = rack_per_lower_bound;
3624 		logged |= 4;
3625 	} else if (rack->rc_gp_saw_ca) {
3626 		/* Sent in CA */
3627 		if (timely_says == 2) {
3628 			new_per = rack_decrease_highrtt(rack, rack->r_ctl.rack_per_of_gp_ca, rtt);
3629 			alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
3630 			if (alt < new_per)
3631 				val = alt;
3632 			else
3633 				val = new_per;
3634 		} else
3635 			val = new_per = alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_ca, rtt_diff);
3636 		if (rack->r_ctl.rack_per_of_gp_ca > val) {
3637 			ca_red = rack->r_ctl.rack_per_of_gp_ca - val;
3638 			rack->r_ctl.rack_per_of_gp_ca = (uint16_t)val;
3639 		} else {
3640 			rack->r_ctl.rack_per_of_gp_ca = rack_per_lower_bound;
3641 			ca_red = 0;
3642 			logvar = new_per;
3643 			logvar <<= 32;
3644 			logvar |= alt;
3645 			logvar2 = (uint32_t)rtt;
3646 			logvar2 <<= 32;
3647 			logvar2 |= (uint32_t)rtt_diff;
3648 			logvar3 = rack_gp_rtt_maxmul;
3649 			logvar3 <<= 32;
3650 			logvar3 |= get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
3651 			rack_log_timely(rack, timely_says,
3652 					logvar2, logvar3,
3653 					logvar, __LINE__, 10);
3654 		}
3655 		if (rack_per_lower_bound > rack->r_ctl.rack_per_of_gp_ca)
3656 			rack->r_ctl.rack_per_of_gp_ca = rack_per_lower_bound;
3657 		logged |= 2;
3658 	}
3659 	if (rack->rc_gp_timely_dec_cnt < 0x7) {
3660 		rack->rc_gp_timely_dec_cnt++;
3661 		if (rack_timely_dec_clear &&
3662 		    (rack->rc_gp_timely_dec_cnt == rack_timely_dec_clear))
3663 			rack->rc_gp_timely_dec_cnt = 0;
3664 	}
3665 	logvar = ss_red;
3666 	logvar <<= 32;
3667 	logvar |= ca_red;
3668 	rack_log_timely(rack,  logged, rec_red, rack_per_lower_bound, logvar,
3669 			__LINE__, 2);
3670 }
3671 
3672 static void
3673 rack_log_rtt_shrinks(struct tcp_rack *rack, uint32_t us_cts,
3674 		     uint32_t rtt, uint32_t line, uint8_t reas)
3675 {
3676 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
3677 		union tcp_log_stackspecific log;
3678 		struct timeval tv;
3679 
3680 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
3681 		log.u_bbr.flex1 = line;
3682 		log.u_bbr.flex2 = rack->r_ctl.rc_time_probertt_starts;
3683 		log.u_bbr.flex3 = rack->r_ctl.rc_lower_rtt_us_cts;
3684 		log.u_bbr.flex4 = rack->r_ctl.rack_per_of_gp_ss;
3685 		log.u_bbr.flex5 = rtt;
3686 		log.u_bbr.flex6 = rack->rc_highly_buffered;
3687 		log.u_bbr.flex6 <<= 1;
3688 		log.u_bbr.flex6 |= rack->forced_ack;
3689 		log.u_bbr.flex6 <<= 1;
3690 		log.u_bbr.flex6 |= rack->rc_gp_dyn_mul;
3691 		log.u_bbr.flex6 <<= 1;
3692 		log.u_bbr.flex6 |= rack->in_probe_rtt;
3693 		log.u_bbr.flex6 <<= 1;
3694 		log.u_bbr.flex6 |= rack->measure_saw_probe_rtt;
3695 		log.u_bbr.flex7 = rack->r_ctl.rack_per_of_gp_probertt;
3696 		log.u_bbr.pacing_gain = rack->r_ctl.rack_per_of_gp_ca;
3697 		log.u_bbr.cwnd_gain = rack->r_ctl.rack_per_of_gp_rec;
3698 		log.u_bbr.flex8 = reas;
3699 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
3700 		log.u_bbr.delRate = rack_get_bw(rack);
3701 		log.u_bbr.cur_del_rate = rack->r_ctl.rc_highest_us_rtt;
3702 		log.u_bbr.cur_del_rate <<= 32;
3703 		log.u_bbr.cur_del_rate |= rack->r_ctl.rc_lowest_us_rtt;
3704 		log.u_bbr.applimited = rack->r_ctl.rc_time_probertt_entered;
3705 		log.u_bbr.pkts_out = rack->r_ctl.rc_rtt_diff;
3706 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
3707 		log.u_bbr.epoch = rack->r_ctl.rc_gp_srtt;
3708 		log.u_bbr.lt_epoch = rack->r_ctl.rc_prev_gp_srtt;
3709 		log.u_bbr.pkt_epoch = rack->r_ctl.rc_lower_rtt_us_cts;
3710 		log.u_bbr.delivered = rack->r_ctl.rc_target_probertt_flight;
3711 		log.u_bbr.lost = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
3712 		log.u_bbr.rttProp = us_cts;
3713 		log.u_bbr.rttProp <<= 32;
3714 		log.u_bbr.rttProp |= rack->r_ctl.rc_entry_gp_rtt;
3715 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
3716 		    &rack->rc_inp->inp_socket->so_rcv,
3717 		    &rack->rc_inp->inp_socket->so_snd,
3718 		    BBR_LOG_RTT_SHRINKS, 0,
3719 		    0, &log, false, &rack->r_ctl.act_rcv_time);
3720 	}
3721 }
3722 
3723 static void
3724 rack_set_prtt_target(struct tcp_rack *rack, uint32_t segsiz, uint32_t rtt)
3725 {
3726 	uint64_t bwdp;
3727 
3728 	bwdp = rack_get_bw(rack);
3729 	bwdp *= (uint64_t)rtt;
3730 	bwdp /= (uint64_t)HPTS_USEC_IN_SEC;
3731 	rack->r_ctl.rc_target_probertt_flight = roundup((uint32_t)bwdp, segsiz);
3732 	if (rack->r_ctl.rc_target_probertt_flight < (segsiz * rack_timely_min_segs)) {
3733 		/*
3734 		 * A window protocol must be able to have 4 packets
3735 		 * outstanding as the floor in order to function
3736 		 * (especially considering delayed ack :D).
3737 		 */
3738 		rack->r_ctl.rc_target_probertt_flight = (segsiz * rack_timely_min_segs);
3739 	}
3740 }
3741 
3742 static void
3743 rack_enter_probertt(struct tcp_rack *rack, uint32_t us_cts)
3744 {
3745 	/**
3746 	 * ProbeRTT is a bit different in rack_pacing than in
3747 	 * BBR. It is like BBR in that it uses the lowering of
3748 	 * the RTT as a signal that we saw something new and
3749 	 * counts from there for how long between. But it is
3750 	 * different in that its quite simple. It does not
3751 	 * play with the cwnd and wait until we get down
3752 	 * to N segments outstanding and hold that for
3753 	 * 200ms. Instead it just sets the pacing reduction
3754 	 * rate to a set percentage (70 by default) and hold
3755 	 * that for a number of recent GP Srtt's.
3756 	 */
3757 	uint32_t segsiz;
3758 
3759 	if (rack->rc_gp_dyn_mul == 0)
3760 		return;
3761 
3762 	if (rack->rc_tp->snd_max == rack->rc_tp->snd_una) {
3763 		/* We are idle */
3764 		return;
3765 	}
3766 	if ((rack->rc_tp->t_flags & TF_GPUTINPROG) &&
3767 	    SEQ_GT(rack->rc_tp->snd_una, rack->rc_tp->gput_seq)) {
3768 		/*
3769 		 * Stop the goodput now, the idea here is
3770 		 * that future measurements with in_probe_rtt
3771 		 * won't register if they are not greater so
3772 		 * we want to get what info (if any) is available
3773 		 * now.
3774 		 */
3775 		rack_do_goodput_measurement(rack->rc_tp, rack,
3776 					    rack->rc_tp->snd_una, __LINE__,
3777 					    RACK_QUALITY_PROBERTT);
3778 	}
3779 	rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt;
3780 	rack->r_ctl.rc_time_probertt_entered = us_cts;
3781 	segsiz = min(ctf_fixed_maxseg(rack->rc_tp),
3782 		     rack->r_ctl.rc_pace_min_segs);
3783 	rack->in_probe_rtt = 1;
3784 	rack->measure_saw_probe_rtt = 1;
3785 	rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
3786 	rack->r_ctl.rc_time_probertt_starts = 0;
3787 	rack->r_ctl.rc_entry_gp_rtt = rack->r_ctl.rc_gp_srtt;
3788 	if (rack_probertt_use_min_rtt_entry)
3789 		rack_set_prtt_target(rack, segsiz, get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt));
3790 	else
3791 		rack_set_prtt_target(rack, segsiz, rack->r_ctl.rc_gp_srtt);
3792 	rack_log_rtt_shrinks(rack,  us_cts,  get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3793 			     __LINE__, RACK_RTTS_ENTERPROBE);
3794 }
3795 
3796 static void
3797 rack_exit_probertt(struct tcp_rack *rack, uint32_t us_cts)
3798 {
3799 	struct rack_sendmap *rsm;
3800 	uint32_t segsiz;
3801 
3802 	segsiz = min(ctf_fixed_maxseg(rack->rc_tp),
3803 		     rack->r_ctl.rc_pace_min_segs);
3804 	rack->in_probe_rtt = 0;
3805 	if ((rack->rc_tp->t_flags & TF_GPUTINPROG) &&
3806 	    SEQ_GT(rack->rc_tp->snd_una, rack->rc_tp->gput_seq)) {
3807 		/*
3808 		 * Stop the goodput now, the idea here is
3809 		 * that future measurements with in_probe_rtt
3810 		 * won't register if they are not greater so
3811 		 * we want to get what info (if any) is available
3812 		 * now.
3813 		 */
3814 		rack_do_goodput_measurement(rack->rc_tp, rack,
3815 					    rack->rc_tp->snd_una, __LINE__,
3816 					    RACK_QUALITY_PROBERTT);
3817 	} else if (rack->rc_tp->t_flags & TF_GPUTINPROG) {
3818 		/*
3819 		 * We don't have enough data to make a measurement.
3820 		 * So lets just stop and start here after exiting
3821 		 * probe-rtt. We probably are not interested in
3822 		 * the results anyway.
3823 		 */
3824 		rack->rc_tp->t_flags &= ~TF_GPUTINPROG;
3825 	}
3826 	/*
3827 	 * Measurements through the current snd_max are going
3828 	 * to be limited by the slower pacing rate.
3829 	 *
3830 	 * We need to mark these as app-limited so we
3831 	 * don't collapse the b/w.
3832 	 */
3833 	rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
3834 	if (rsm && ((rsm->r_flags & RACK_APP_LIMITED) == 0)) {
3835 		if (rack->r_ctl.rc_app_limited_cnt == 0)
3836 			rack->r_ctl.rc_end_appl = rack->r_ctl.rc_first_appl = rsm;
3837 		else {
3838 			/*
3839 			 * Go out to the end app limited and mark
3840 			 * this new one as next and move the end_appl up
3841 			 * to this guy.
3842 			 */
3843 			if (rack->r_ctl.rc_end_appl)
3844 				rack->r_ctl.rc_end_appl->r_nseq_appl = rsm->r_start;
3845 			rack->r_ctl.rc_end_appl = rsm;
3846 		}
3847 		rsm->r_flags |= RACK_APP_LIMITED;
3848 		rack->r_ctl.rc_app_limited_cnt++;
3849 	}
3850 	/*
3851 	 * Now, we need to examine our pacing rate multipliers.
3852 	 * If its under 100%, we need to kick it back up to
3853 	 * 100%. We also don't let it be over our "max" above
3854 	 * the actual rate i.e. 100% + rack_clamp_atexit_prtt.
3855 	 * Note setting clamp_atexit_prtt to 0 has the effect
3856 	 * of setting CA/SS to 100% always at exit (which is
3857 	 * the default behavior).
3858 	 */
3859 	if (rack_probertt_clear_is) {
3860 		rack->rc_gp_incr = 0;
3861 		rack->rc_gp_bwred = 0;
3862 		rack->rc_gp_timely_inc_cnt = 0;
3863 		rack->rc_gp_timely_dec_cnt = 0;
3864 	}
3865 	/* Do we do any clamping at exit? */
3866 	if (rack->rc_highly_buffered && rack_atexit_prtt_hbp) {
3867 		rack->r_ctl.rack_per_of_gp_ca = rack_atexit_prtt_hbp;
3868 		rack->r_ctl.rack_per_of_gp_ss = rack_atexit_prtt_hbp;
3869 	}
3870 	if ((rack->rc_highly_buffered == 0) && rack_atexit_prtt) {
3871 		rack->r_ctl.rack_per_of_gp_ca = rack_atexit_prtt;
3872 		rack->r_ctl.rack_per_of_gp_ss = rack_atexit_prtt;
3873 	}
3874 	/*
3875 	 * Lets set rtt_diff to 0, so that we will get a "boost"
3876 	 * after exiting.
3877 	 */
3878 	rack->r_ctl.rc_rtt_diff = 0;
3879 
3880 	/* Clear all flags so we start fresh */
3881 	rack->rc_tp->t_bytes_acked = 0;
3882 	rack->rc_tp->ccv->flags &= ~CCF_ABC_SENTAWND;
3883 	/*
3884 	 * If configured to, set the cwnd and ssthresh to
3885 	 * our targets.
3886 	 */
3887 	if (rack_probe_rtt_sets_cwnd) {
3888 		uint64_t ebdp;
3889 		uint32_t setto;
3890 
3891 		/* Set ssthresh so we get into CA once we hit our target */
3892 		if (rack_probertt_use_min_rtt_exit == 1) {
3893 			/* Set to min rtt */
3894 			rack_set_prtt_target(rack, segsiz,
3895 					     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt));
3896 		} else if (rack_probertt_use_min_rtt_exit == 2) {
3897 			/* Set to current gp rtt */
3898 			rack_set_prtt_target(rack, segsiz,
3899 					     rack->r_ctl.rc_gp_srtt);
3900 		} else if (rack_probertt_use_min_rtt_exit == 3) {
3901 			/* Set to entry gp rtt */
3902 			rack_set_prtt_target(rack, segsiz,
3903 					     rack->r_ctl.rc_entry_gp_rtt);
3904 		} else {
3905 			uint64_t sum;
3906 			uint32_t setval;
3907 
3908 			sum = rack->r_ctl.rc_entry_gp_rtt;
3909 			sum *= 10;
3910 			sum /= (uint64_t)(max(1, rack->r_ctl.rc_gp_srtt));
3911 			if (sum >= 20) {
3912 				/*
3913 				 * A highly buffered path needs
3914 				 * cwnd space for timely to work.
3915 				 * Lets set things up as if
3916 				 * we are heading back here again.
3917 				 */
3918 				setval = rack->r_ctl.rc_entry_gp_rtt;
3919 			} else if (sum >= 15) {
3920 				/*
3921 				 * Lets take the smaller of the
3922 				 * two since we are just somewhat
3923 				 * buffered.
3924 				 */
3925 				setval = rack->r_ctl.rc_gp_srtt;
3926 				if (setval > rack->r_ctl.rc_entry_gp_rtt)
3927 					setval = rack->r_ctl.rc_entry_gp_rtt;
3928 			} else {
3929 				/*
3930 				 * Here we are not highly buffered
3931 				 * and should pick the min we can to
3932 				 * keep from causing loss.
3933 				 */
3934 				setval = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
3935 			}
3936 			rack_set_prtt_target(rack, segsiz,
3937 					     setval);
3938 		}
3939 		if (rack_probe_rtt_sets_cwnd > 1) {
3940 			/* There is a percentage here to boost */
3941 			ebdp = rack->r_ctl.rc_target_probertt_flight;
3942 			ebdp *= rack_probe_rtt_sets_cwnd;
3943 			ebdp /= 100;
3944 			setto = rack->r_ctl.rc_target_probertt_flight + ebdp;
3945 		} else
3946 			setto = rack->r_ctl.rc_target_probertt_flight;
3947 		rack->rc_tp->snd_cwnd = roundup(setto, segsiz);
3948 		if (rack->rc_tp->snd_cwnd < (segsiz * rack_timely_min_segs)) {
3949 			/* Enforce a min */
3950 			rack->rc_tp->snd_cwnd = segsiz * rack_timely_min_segs;
3951 		}
3952 		/* If we set in the cwnd also set the ssthresh point so we are in CA */
3953 		rack->rc_tp->snd_ssthresh = (rack->rc_tp->snd_cwnd - 1);
3954 	}
3955 	rack_log_rtt_shrinks(rack,  us_cts,
3956 			     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3957 			     __LINE__, RACK_RTTS_EXITPROBE);
3958 	/* Clear times last so log has all the info */
3959 	rack->r_ctl.rc_probertt_sndmax_atexit = rack->rc_tp->snd_max;
3960 	rack->r_ctl.rc_time_probertt_entered = us_cts;
3961 	rack->r_ctl.rc_time_probertt_starts = rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
3962 	rack->r_ctl.rc_time_of_last_probertt = us_cts;
3963 }
3964 
3965 static void
3966 rack_check_probe_rtt(struct tcp_rack *rack, uint32_t us_cts)
3967 {
3968 	/* Check in on probe-rtt */
3969 	if (rack->rc_gp_filled == 0) {
3970 		/* We do not do p-rtt unless we have gp measurements */
3971 		return;
3972 	}
3973 	if (rack->in_probe_rtt) {
3974 		uint64_t no_overflow;
3975 		uint32_t endtime, must_stay;
3976 
3977 		if (rack->r_ctl.rc_went_idle_time &&
3978 		    ((us_cts - rack->r_ctl.rc_went_idle_time) > rack_min_probertt_hold)) {
3979 			/*
3980 			 * We went idle during prtt, just exit now.
3981 			 */
3982 			rack_exit_probertt(rack, us_cts);
3983 		} else if (rack_probe_rtt_safety_val &&
3984 		    TSTMP_GT(us_cts, rack->r_ctl.rc_time_probertt_entered) &&
3985 		    ((us_cts - rack->r_ctl.rc_time_probertt_entered) > rack_probe_rtt_safety_val)) {
3986 			/*
3987 			 * Probe RTT safety value triggered!
3988 			 */
3989 			rack_log_rtt_shrinks(rack,  us_cts,
3990 					     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3991 					     __LINE__, RACK_RTTS_SAFETY);
3992 			rack_exit_probertt(rack, us_cts);
3993 		}
3994 		/* Calculate the max we will wait */
3995 		endtime = rack->r_ctl.rc_time_probertt_entered + (rack->r_ctl.rc_gp_srtt * rack_max_drain_wait);
3996 		if (rack->rc_highly_buffered)
3997 			endtime += (rack->r_ctl.rc_gp_srtt * rack_max_drain_hbp);
3998 		/* Calculate the min we must wait */
3999 		must_stay = rack->r_ctl.rc_time_probertt_entered + (rack->r_ctl.rc_gp_srtt * rack_must_drain);
4000 		if ((ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) > rack->r_ctl.rc_target_probertt_flight) &&
4001 		    TSTMP_LT(us_cts, endtime)) {
4002 			uint32_t calc;
4003 			/* Do we lower more? */
4004 no_exit:
4005 			if (TSTMP_GT(us_cts, rack->r_ctl.rc_time_probertt_entered))
4006 				calc = us_cts - rack->r_ctl.rc_time_probertt_entered;
4007 			else
4008 				calc = 0;
4009 			calc /= max(rack->r_ctl.rc_gp_srtt, 1);
4010 			if (calc) {
4011 				/* Maybe */
4012 				calc *= rack_per_of_gp_probertt_reduce;
4013 				rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt - calc;
4014 				/* Limit it too */
4015 				if (rack->r_ctl.rack_per_of_gp_probertt < rack_per_of_gp_lowthresh)
4016 					rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_lowthresh;
4017 			}
4018 			/* We must reach target or the time set */
4019 			return;
4020 		}
4021 		if (rack->r_ctl.rc_time_probertt_starts == 0) {
4022 			if ((TSTMP_LT(us_cts, must_stay) &&
4023 			     rack->rc_highly_buffered) ||
4024 			     (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) >
4025 			      rack->r_ctl.rc_target_probertt_flight)) {
4026 				/* We are not past the must_stay time */
4027 				goto no_exit;
4028 			}
4029 			rack_log_rtt_shrinks(rack,  us_cts,
4030 					     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
4031 					     __LINE__, RACK_RTTS_REACHTARGET);
4032 			rack->r_ctl.rc_time_probertt_starts = us_cts;
4033 			if (rack->r_ctl.rc_time_probertt_starts == 0)
4034 				rack->r_ctl.rc_time_probertt_starts = 1;
4035 			/* Restore back to our rate we want to pace at in prtt */
4036 			rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt;
4037 		}
4038 		/*
4039 		 * Setup our end time, some number of gp_srtts plus 200ms.
4040 		 */
4041 		no_overflow = ((uint64_t)rack->r_ctl.rc_gp_srtt *
4042 			       (uint64_t)rack_probertt_gpsrtt_cnt_mul);
4043 		if (rack_probertt_gpsrtt_cnt_div)
4044 			endtime = (uint32_t)(no_overflow / (uint64_t)rack_probertt_gpsrtt_cnt_div);
4045 		else
4046 			endtime = 0;
4047 		endtime += rack_min_probertt_hold;
4048 		endtime += rack->r_ctl.rc_time_probertt_starts;
4049 		if (TSTMP_GEQ(us_cts,  endtime)) {
4050 			/* yes, exit probertt */
4051 			rack_exit_probertt(rack, us_cts);
4052 		}
4053 
4054 	} else if ((us_cts - rack->r_ctl.rc_lower_rtt_us_cts) >= rack_time_between_probertt) {
4055 		/* Go into probertt, its been too long since we went lower */
4056 		rack_enter_probertt(rack, us_cts);
4057 	}
4058 }
4059 
4060 static void
4061 rack_update_multiplier(struct tcp_rack *rack, int32_t timely_says, uint64_t last_bw_est,
4062 		       uint32_t rtt, int32_t rtt_diff)
4063 {
4064 	uint64_t cur_bw, up_bnd, low_bnd, subfr;
4065 	uint32_t losses;
4066 
4067 	if ((rack->rc_gp_dyn_mul == 0) ||
4068 	    (rack->use_fixed_rate) ||
4069 	    (rack->in_probe_rtt) ||
4070 	    (rack->rc_always_pace == 0)) {
4071 		/* No dynamic GP multipler in play */
4072 		return;
4073 	}
4074 	losses = rack->r_ctl.rc_loss_count - rack->r_ctl.rc_loss_at_start;
4075 	cur_bw = rack_get_bw(rack);
4076 	/* Calculate our up and down range */
4077 	up_bnd = rack->r_ctl.last_gp_comp_bw * (uint64_t)rack_gp_per_bw_mul_up;
4078 	up_bnd /= 100;
4079 	up_bnd += rack->r_ctl.last_gp_comp_bw;
4080 
4081 	subfr = (uint64_t)rack->r_ctl.last_gp_comp_bw * (uint64_t)rack_gp_per_bw_mul_down;
4082 	subfr /= 100;
4083 	low_bnd = rack->r_ctl.last_gp_comp_bw - subfr;
4084 	if ((timely_says == 2) && (rack->r_ctl.rc_no_push_at_mrtt)) {
4085 		/*
4086 		 * This is the case where our RTT is above
4087 		 * the max target and we have been configured
4088 		 * to just do timely no bonus up stuff in that case.
4089 		 *
4090 		 * There are two configurations, set to 1, and we
4091 		 * just do timely if we are over our max. If its
4092 		 * set above 1 then we slam the multipliers down
4093 		 * to 100 and then decrement per timely.
4094 		 */
4095 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
4096 				__LINE__, 3);
4097 		if (rack->r_ctl.rc_no_push_at_mrtt > 1)
4098 			rack_validate_multipliers_at_or_below_100(rack);
4099 		rack_decrease_bw_mul(rack, timely_says, rtt, rtt_diff);
4100 	} else if ((last_bw_est < low_bnd) && !losses) {
4101 		/*
4102 		 * We are decreasing this is a bit complicated this
4103 		 * means we are loosing ground. This could be
4104 		 * because another flow entered and we are competing
4105 		 * for b/w with it. This will push the RTT up which
4106 		 * makes timely unusable unless we want to get shoved
4107 		 * into a corner and just be backed off (the age
4108 		 * old problem with delay based CC).
4109 		 *
4110 		 * On the other hand if it was a route change we
4111 		 * would like to stay somewhat contained and not
4112 		 * blow out the buffers.
4113 		 */
4114 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
4115 				__LINE__, 3);
4116 		rack->r_ctl.last_gp_comp_bw = cur_bw;
4117 		if (rack->rc_gp_bwred == 0) {
4118 			/* Go into reduction counting */
4119 			rack->rc_gp_bwred = 1;
4120 			rack->rc_gp_timely_dec_cnt = 0;
4121 		}
4122 		if ((rack->rc_gp_timely_dec_cnt < rack_timely_max_push_drop) ||
4123 		    (timely_says == 0)) {
4124 			/*
4125 			 * Push another time with a faster pacing
4126 			 * to try to gain back (we include override to
4127 			 * get a full raise factor).
4128 			 */
4129 			if ((rack->rc_gp_saw_ca && rack->r_ctl.rack_per_of_gp_ca <= rack_down_raise_thresh) ||
4130 			    (rack->rc_gp_saw_ss && rack->r_ctl.rack_per_of_gp_ss <= rack_down_raise_thresh) ||
4131 			    (timely_says == 0) ||
4132 			    (rack_down_raise_thresh == 0)) {
4133 				/*
4134 				 * Do an override up in b/w if we were
4135 				 * below the threshold or if the threshold
4136 				 * is zero we always do the raise.
4137 				 */
4138 				rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 1);
4139 			} else {
4140 				/* Log it stays the same */
4141 				rack_log_timely(rack,  0, last_bw_est, low_bnd, 0,
4142 						__LINE__, 11);
4143 			}
4144 			rack->rc_gp_timely_dec_cnt++;
4145 			/* We are not incrementing really no-count */
4146 			rack->rc_gp_incr = 0;
4147 			rack->rc_gp_timely_inc_cnt = 0;
4148 		} else {
4149 			/*
4150 			 * Lets just use the RTT
4151 			 * information and give up
4152 			 * pushing.
4153 			 */
4154 			goto use_timely;
4155 		}
4156 	} else if ((timely_says != 2) &&
4157 		    !losses &&
4158 		    (last_bw_est > up_bnd)) {
4159 		/*
4160 		 * We are increasing b/w lets keep going, updating
4161 		 * our b/w and ignoring any timely input, unless
4162 		 * of course we are at our max raise (if there is one).
4163 		 */
4164 
4165 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
4166 				__LINE__, 3);
4167 		rack->r_ctl.last_gp_comp_bw = cur_bw;
4168 		if (rack->rc_gp_saw_ss &&
4169 		    rack_per_upper_bound_ss &&
4170 		     (rack->r_ctl.rack_per_of_gp_ss == rack_per_upper_bound_ss)) {
4171 			    /*
4172 			     * In cases where we can't go higher
4173 			     * we should just use timely.
4174 			     */
4175 			    goto use_timely;
4176 		}
4177 		if (rack->rc_gp_saw_ca &&
4178 		    rack_per_upper_bound_ca &&
4179 		    (rack->r_ctl.rack_per_of_gp_ca == rack_per_upper_bound_ca)) {
4180 			    /*
4181 			     * In cases where we can't go higher
4182 			     * we should just use timely.
4183 			     */
4184 			    goto use_timely;
4185 		}
4186 		rack->rc_gp_bwred = 0;
4187 		rack->rc_gp_timely_dec_cnt = 0;
4188 		/* You get a set number of pushes if timely is trying to reduce */
4189 		if ((rack->rc_gp_incr < rack_timely_max_push_rise) || (timely_says == 0)) {
4190 			rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 0);
4191 		} else {
4192 			/* Log it stays the same */
4193 			rack_log_timely(rack,  0, last_bw_est, up_bnd, 0,
4194 			    __LINE__, 12);
4195 		}
4196 		return;
4197 	} else {
4198 		/*
4199 		 * We are staying between the lower and upper range bounds
4200 		 * so use timely to decide.
4201 		 */
4202 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
4203 				__LINE__, 3);
4204 use_timely:
4205 		if (timely_says) {
4206 			rack->rc_gp_incr = 0;
4207 			rack->rc_gp_timely_inc_cnt = 0;
4208 			if ((rack->rc_gp_timely_dec_cnt < rack_timely_max_push_drop) &&
4209 			    !losses &&
4210 			    (last_bw_est < low_bnd)) {
4211 				/* We are loosing ground */
4212 				rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 0);
4213 				rack->rc_gp_timely_dec_cnt++;
4214 				/* We are not incrementing really no-count */
4215 				rack->rc_gp_incr = 0;
4216 				rack->rc_gp_timely_inc_cnt = 0;
4217 			} else
4218 				rack_decrease_bw_mul(rack, timely_says, rtt, rtt_diff);
4219 		} else {
4220 			rack->rc_gp_bwred = 0;
4221 			rack->rc_gp_timely_dec_cnt = 0;
4222 			rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 0);
4223 		}
4224 	}
4225 }
4226 
4227 static int32_t
4228 rack_make_timely_judgement(struct tcp_rack *rack, uint32_t rtt, int32_t rtt_diff, uint32_t prev_rtt)
4229 {
4230 	int32_t timely_says;
4231 	uint64_t log_mult, log_rtt_a_diff;
4232 
4233 	log_rtt_a_diff = rtt;
4234 	log_rtt_a_diff <<= 32;
4235 	log_rtt_a_diff |= (uint32_t)rtt_diff;
4236 	if (rtt >= (get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) *
4237 		    rack_gp_rtt_maxmul)) {
4238 		/* Reduce the b/w multipler */
4239 		timely_says = 2;
4240 		log_mult = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_maxmul;
4241 		log_mult <<= 32;
4242 		log_mult |= prev_rtt;
4243 		rack_log_timely(rack,  timely_says, log_mult,
4244 				get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
4245 				log_rtt_a_diff, __LINE__, 4);
4246 	} else if (rtt <= (get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) +
4247 			   ((get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_minmul) /
4248 			    max(rack_gp_rtt_mindiv , 1)))) {
4249 		/* Increase the b/w multipler */
4250 		log_mult = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) +
4251 			((get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_minmul) /
4252 			 max(rack_gp_rtt_mindiv , 1));
4253 		log_mult <<= 32;
4254 		log_mult |= prev_rtt;
4255 		timely_says = 0;
4256 		rack_log_timely(rack,  timely_says, log_mult ,
4257 				get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
4258 				log_rtt_a_diff, __LINE__, 5);
4259 	} else {
4260 		/*
4261 		 * Use a gradient to find it the timely gradient
4262 		 * is:
4263 		 * grad = rc_rtt_diff / min_rtt;
4264 		 *
4265 		 * anything below or equal to 0 will be
4266 		 * a increase indication. Anything above
4267 		 * zero is a decrease. Note we take care
4268 		 * of the actual gradient calculation
4269 		 * in the reduction (its not needed for
4270 		 * increase).
4271 		 */
4272 		log_mult = prev_rtt;
4273 		if (rtt_diff <= 0) {
4274 			/*
4275 			 * Rttdiff is less than zero, increase the
4276 			 * b/w multipler (its 0 or negative)
4277 			 */
4278 			timely_says = 0;
4279 			rack_log_timely(rack,  timely_says, log_mult,
4280 					get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt), log_rtt_a_diff, __LINE__, 6);
4281 		} else {
4282 			/* Reduce the b/w multipler */
4283 			timely_says = 1;
4284 			rack_log_timely(rack,  timely_says, log_mult,
4285 					get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt), log_rtt_a_diff, __LINE__, 7);
4286 		}
4287 	}
4288 	return (timely_says);
4289 }
4290 
4291 static void
4292 rack_do_goodput_measurement(struct tcpcb *tp, struct tcp_rack *rack,
4293 			    tcp_seq th_ack, int line, uint8_t quality)
4294 {
4295 	uint64_t tim, bytes_ps, ltim, stim, utim;
4296 	uint32_t segsiz, bytes, reqbytes, us_cts;
4297 	int32_t gput, new_rtt_diff, timely_says;
4298 	uint64_t  resid_bw, subpart = 0, addpart = 0, srtt;
4299 	int did_add = 0;
4300 
4301 	us_cts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
4302 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
4303 	if (TSTMP_GEQ(us_cts, tp->gput_ts))
4304 		tim = us_cts - tp->gput_ts;
4305 	else
4306 		tim = 0;
4307 	if (rack->r_ctl.rc_gp_cumack_ts > rack->r_ctl.rc_gp_output_ts)
4308 		stim = rack->r_ctl.rc_gp_cumack_ts - rack->r_ctl.rc_gp_output_ts;
4309 	else
4310 		stim = 0;
4311 	/*
4312 	 * Use the larger of the send time or ack time. This prevents us
4313 	 * from being influenced by ack artifacts to come up with too
4314 	 * high of measurement. Note that since we are spanning over many more
4315 	 * bytes in most of our measurements hopefully that is less likely to
4316 	 * occur.
4317 	 */
4318 	if (tim > stim)
4319 		utim = max(tim, 1);
4320 	else
4321 		utim = max(stim, 1);
4322 	/* Lets get a msec time ltim too for the old stuff */
4323 	ltim = max(1, (utim / HPTS_USEC_IN_MSEC));
4324 	gput = (((uint64_t) (th_ack - tp->gput_seq)) << 3) / ltim;
4325 	reqbytes = min(rc_init_window(rack), (MIN_GP_WIN * segsiz));
4326 	if ((tim == 0) && (stim == 0)) {
4327 		/*
4328 		 * Invalid measurement time, maybe
4329 		 * all on one ack/one send?
4330 		 */
4331 		bytes = 0;
4332 		bytes_ps = 0;
4333 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
4334 					   0, 0, 0, 10, __LINE__, NULL, quality);
4335 		goto skip_measurement;
4336 	}
4337 	if (rack->r_ctl.rc_gp_lowrtt == 0xffffffff) {
4338 		/* We never made a us_rtt measurement? */
4339 		bytes = 0;
4340 		bytes_ps = 0;
4341 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
4342 					   0, 0, 0, 10, __LINE__, NULL, quality);
4343 		goto skip_measurement;
4344 	}
4345 	/*
4346 	 * Calculate the maximum possible b/w this connection
4347 	 * could have. We base our calculation on the lowest
4348 	 * rtt we have seen during the measurement and the
4349 	 * largest rwnd the client has given us in that time. This
4350 	 * forms a BDP that is the maximum that we could ever
4351 	 * get to the client. Anything larger is not valid.
4352 	 *
4353 	 * I originally had code here that rejected measurements
4354 	 * where the time was less than 1/2 the latest us_rtt.
4355 	 * But after thinking on that I realized its wrong since
4356 	 * say you had a 150Mbps or even 1Gbps link, and you
4357 	 * were a long way away.. example I am in Europe (100ms rtt)
4358 	 * talking to my 1Gbps link in S.C. Now measuring say 150,000
4359 	 * bytes my time would be 1.2ms, and yet my rtt would say
4360 	 * the measurement was invalid the time was < 50ms. The
4361 	 * same thing is true for 150Mb (8ms of time).
4362 	 *
4363 	 * A better way I realized is to look at what the maximum
4364 	 * the connection could possibly do. This is gated on
4365 	 * the lowest RTT we have seen and the highest rwnd.
4366 	 * We should in theory never exceed that, if we are
4367 	 * then something on the path is storing up packets
4368 	 * and then feeding them all at once to our endpoint
4369 	 * messing up our measurement.
4370 	 */
4371 	rack->r_ctl.last_max_bw = rack->r_ctl.rc_gp_high_rwnd;
4372 	rack->r_ctl.last_max_bw *= HPTS_USEC_IN_SEC;
4373 	rack->r_ctl.last_max_bw /= rack->r_ctl.rc_gp_lowrtt;
4374 	if (SEQ_LT(th_ack, tp->gput_seq)) {
4375 		/* No measurement can be made */
4376 		bytes = 0;
4377 		bytes_ps = 0;
4378 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
4379 					   0, 0, 0, 10, __LINE__, NULL, quality);
4380 		goto skip_measurement;
4381 	} else
4382 		bytes = (th_ack - tp->gput_seq);
4383 	bytes_ps = (uint64_t)bytes;
4384 	/*
4385 	 * Don't measure a b/w for pacing unless we have gotten at least
4386 	 * an initial windows worth of data in this measurement interval.
4387 	 *
4388 	 * Small numbers of bytes get badly influenced by delayed ack and
4389 	 * other artifacts. Note we take the initial window or our
4390 	 * defined minimum GP (defaulting to 10 which hopefully is the
4391 	 * IW).
4392 	 */
4393 	if (rack->rc_gp_filled == 0) {
4394 		/*
4395 		 * The initial estimate is special. We
4396 		 * have blasted out an IW worth of packets
4397 		 * without a real valid ack ts results. We
4398 		 * then setup the app_limited_needs_set flag,
4399 		 * this should get the first ack in (probably 2
4400 		 * MSS worth) to be recorded as the timestamp.
4401 		 * We thus allow a smaller number of bytes i.e.
4402 		 * IW - 2MSS.
4403 		 */
4404 		reqbytes -= (2 * segsiz);
4405 		/* Also lets fill previous for our first measurement to be neutral */
4406 		rack->r_ctl.rc_prev_gp_srtt = rack->r_ctl.rc_gp_srtt;
4407 	}
4408 	if ((bytes_ps < reqbytes) || rack->app_limited_needs_set) {
4409 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
4410 					   rack->r_ctl.rc_app_limited_cnt,
4411 					   0, 0, 10, __LINE__, NULL, quality);
4412 		goto skip_measurement;
4413 	}
4414 	/*
4415 	 * We now need to calculate the Timely like status so
4416 	 * we can update (possibly) the b/w multipliers.
4417 	 */
4418 	new_rtt_diff = (int32_t)rack->r_ctl.rc_gp_srtt - (int32_t)rack->r_ctl.rc_prev_gp_srtt;
4419 	if (rack->rc_gp_filled == 0) {
4420 		/* No previous reading */
4421 		rack->r_ctl.rc_rtt_diff = new_rtt_diff;
4422 	} else {
4423 		if (rack->measure_saw_probe_rtt == 0) {
4424 			/*
4425 			 * We don't want a probertt to be counted
4426 			 * since it will be negative incorrectly. We
4427 			 * expect to be reducing the RTT when we
4428 			 * pace at a slower rate.
4429 			 */
4430 			rack->r_ctl.rc_rtt_diff -= (rack->r_ctl.rc_rtt_diff / 8);
4431 			rack->r_ctl.rc_rtt_diff += (new_rtt_diff / 8);
4432 		}
4433 	}
4434 	timely_says = rack_make_timely_judgement(rack,
4435 		rack->r_ctl.rc_gp_srtt,
4436 		rack->r_ctl.rc_rtt_diff,
4437 	        rack->r_ctl.rc_prev_gp_srtt
4438 		);
4439 	bytes_ps *= HPTS_USEC_IN_SEC;
4440 	bytes_ps /= utim;
4441 	if (bytes_ps > rack->r_ctl.last_max_bw) {
4442 		/*
4443 		 * Something is on path playing
4444 		 * since this b/w is not possible based
4445 		 * on our BDP (highest rwnd and lowest rtt
4446 		 * we saw in the measurement window).
4447 		 *
4448 		 * Another option here would be to
4449 		 * instead skip the measurement.
4450 		 */
4451 		rack_log_pacing_delay_calc(rack, bytes, reqbytes,
4452 					   bytes_ps, rack->r_ctl.last_max_bw, 0,
4453 					   11, __LINE__, NULL, quality);
4454 		bytes_ps = rack->r_ctl.last_max_bw;
4455 	}
4456 	/* We store gp for b/w in bytes per second */
4457 	if (rack->rc_gp_filled == 0) {
4458 		/* Initial measurment */
4459 		if (bytes_ps) {
4460 			rack->r_ctl.gp_bw = bytes_ps;
4461 			rack->rc_gp_filled = 1;
4462 			rack->r_ctl.num_measurements = 1;
4463 			rack_set_pace_segments(rack->rc_tp, rack, __LINE__, NULL);
4464 		} else {
4465 			rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
4466 						   rack->r_ctl.rc_app_limited_cnt,
4467 						   0, 0, 10, __LINE__, NULL, quality);
4468 		}
4469 		if (tcp_in_hpts(rack->rc_inp) &&
4470 		    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
4471 			/*
4472 			 * Ok we can't trust the pacer in this case
4473 			 * where we transition from un-paced to paced.
4474 			 * Or for that matter when the burst mitigation
4475 			 * was making a wild guess and got it wrong.
4476 			 * Stop the pacer and clear up all the aggregate
4477 			 * delays etc.
4478 			 */
4479 			tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
4480 			rack->r_ctl.rc_hpts_flags = 0;
4481 			rack->r_ctl.rc_last_output_to = 0;
4482 		}
4483 		did_add = 2;
4484 	} else if (rack->r_ctl.num_measurements < RACK_REQ_AVG) {
4485 		/* Still a small number run an average */
4486 		rack->r_ctl.gp_bw += bytes_ps;
4487 		addpart = rack->r_ctl.num_measurements;
4488 		rack->r_ctl.num_measurements++;
4489 		if (rack->r_ctl.num_measurements >= RACK_REQ_AVG) {
4490 			/* We have collected enought to move forward */
4491 			rack->r_ctl.gp_bw /= (uint64_t)rack->r_ctl.num_measurements;
4492 		}
4493 		did_add = 3;
4494 	} else {
4495 		/*
4496 		 * We want to take 1/wma of the goodput and add in to 7/8th
4497 		 * of the old value weighted by the srtt. So if your measurement
4498 		 * period is say 2 SRTT's long you would get 1/4 as the
4499 		 * value, if it was like 1/2 SRTT then you would get 1/16th.
4500 		 *
4501 		 * But we must be careful not to take too much i.e. if the
4502 		 * srtt is say 20ms and the measurement is taken over
4503 		 * 400ms our weight would be 400/20 i.e. 20. On the
4504 		 * other hand if we get a measurement over 1ms with a
4505 		 * 10ms rtt we only want to take a much smaller portion.
4506 		 */
4507 		if (rack->r_ctl.num_measurements < 0xff) {
4508 			rack->r_ctl.num_measurements++;
4509 		}
4510 		srtt = (uint64_t)tp->t_srtt;
4511 		if (srtt == 0) {
4512 			/*
4513 			 * Strange why did t_srtt go back to zero?
4514 			 */
4515 			if (rack->r_ctl.rc_rack_min_rtt)
4516 				srtt = rack->r_ctl.rc_rack_min_rtt;
4517 			else
4518 				srtt = HPTS_USEC_IN_MSEC;
4519 		}
4520 		/*
4521 		 * XXXrrs: Note for reviewers, in playing with
4522 		 * dynamic pacing I discovered this GP calculation
4523 		 * as done originally leads to some undesired results.
4524 		 * Basically you can get longer measurements contributing
4525 		 * too much to the WMA. Thus I changed it if you are doing
4526 		 * dynamic adjustments to only do the aportioned adjustment
4527 		 * if we have a very small (time wise) measurement. Longer
4528 		 * measurements just get there weight (defaulting to 1/8)
4529 		 * add to the WMA. We may want to think about changing
4530 		 * this to always do that for both sides i.e. dynamic
4531 		 * and non-dynamic... but considering lots of folks
4532 		 * were playing with this I did not want to change the
4533 		 * calculation per.se. without your thoughts.. Lawerence?
4534 		 * Peter??
4535 		 */
4536 		if (rack->rc_gp_dyn_mul == 0) {
4537 			subpart = rack->r_ctl.gp_bw * utim;
4538 			subpart /= (srtt * 8);
4539 			if (subpart < (rack->r_ctl.gp_bw / 2)) {
4540 				/*
4541 				 * The b/w update takes no more
4542 				 * away then 1/2 our running total
4543 				 * so factor it in.
4544 				 */
4545 				addpart = bytes_ps * utim;
4546 				addpart /= (srtt * 8);
4547 			} else {
4548 				/*
4549 				 * Don't allow a single measurement
4550 				 * to account for more than 1/2 of the
4551 				 * WMA. This could happen on a retransmission
4552 				 * where utim becomes huge compared to
4553 				 * srtt (multiple retransmissions when using
4554 				 * the sending rate which factors in all the
4555 				 * transmissions from the first one).
4556 				 */
4557 				subpart = rack->r_ctl.gp_bw / 2;
4558 				addpart = bytes_ps / 2;
4559 			}
4560 			resid_bw = rack->r_ctl.gp_bw - subpart;
4561 			rack->r_ctl.gp_bw = resid_bw + addpart;
4562 			did_add = 1;
4563 		} else {
4564 			if ((utim / srtt) <= 1) {
4565 				/*
4566 				 * The b/w update was over a small period
4567 				 * of time. The idea here is to prevent a small
4568 				 * measurement time period from counting
4569 				 * too much. So we scale it based on the
4570 				 * time so it attributes less than 1/rack_wma_divisor
4571 				 * of its measurement.
4572 				 */
4573 				subpart = rack->r_ctl.gp_bw * utim;
4574 				subpart /= (srtt * rack_wma_divisor);
4575 				addpart = bytes_ps * utim;
4576 				addpart /= (srtt * rack_wma_divisor);
4577 			} else {
4578 				/*
4579 				 * The scaled measurement was long
4580 				 * enough so lets just add in the
4581 				 * portion of the measurment i.e. 1/rack_wma_divisor
4582 				 */
4583 				subpart = rack->r_ctl.gp_bw / rack_wma_divisor;
4584 				addpart = bytes_ps / rack_wma_divisor;
4585 			}
4586 			if ((rack->measure_saw_probe_rtt == 0) ||
4587 		            (bytes_ps > rack->r_ctl.gp_bw)) {
4588 				/*
4589 				 * For probe-rtt we only add it in
4590 				 * if its larger, all others we just
4591 				 * add in.
4592 				 */
4593 				did_add = 1;
4594 				resid_bw = rack->r_ctl.gp_bw - subpart;
4595 				rack->r_ctl.gp_bw = resid_bw + addpart;
4596 			}
4597 		}
4598 	}
4599 	if ((rack->gp_ready == 0) &&
4600 	    (rack->r_ctl.num_measurements >= rack->r_ctl.req_measurements)) {
4601 		/* We have enough measurements now */
4602 		rack->gp_ready = 1;
4603 		rack_set_cc_pacing(rack);
4604 		if (rack->defer_options)
4605 			rack_apply_deferred_options(rack);
4606 	}
4607 	rack_log_pacing_delay_calc(rack, subpart, addpart, bytes_ps, stim,
4608 				   rack_get_bw(rack), 22, did_add, NULL, quality);
4609 	/* We do not update any multipliers if we are in or have seen a probe-rtt */
4610 	if ((rack->measure_saw_probe_rtt == 0) && rack->rc_gp_rtt_set)
4611 		rack_update_multiplier(rack, timely_says, bytes_ps,
4612 				       rack->r_ctl.rc_gp_srtt,
4613 				       rack->r_ctl.rc_rtt_diff);
4614 	rack_log_pacing_delay_calc(rack, bytes, tim, bytes_ps, stim,
4615 				   rack_get_bw(rack), 3, line, NULL, quality);
4616 	/* reset the gp srtt and setup the new prev */
4617 	rack->r_ctl.rc_prev_gp_srtt = rack->r_ctl.rc_gp_srtt;
4618 	/* Record the lost count for the next measurement */
4619 	rack->r_ctl.rc_loss_at_start = rack->r_ctl.rc_loss_count;
4620 	/*
4621 	 * We restart our diffs based on the gpsrtt in the
4622 	 * measurement window.
4623 	 */
4624 	rack->rc_gp_rtt_set = 0;
4625 	rack->rc_gp_saw_rec = 0;
4626 	rack->rc_gp_saw_ca = 0;
4627 	rack->rc_gp_saw_ss = 0;
4628 	rack->rc_dragged_bottom = 0;
4629 skip_measurement:
4630 
4631 #ifdef STATS
4632 	stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_GPUT,
4633 				 gput);
4634 	/*
4635 	 * XXXLAS: This is a temporary hack, and should be
4636 	 * chained off VOI_TCP_GPUT when stats(9) grows an
4637 	 * API to deal with chained VOIs.
4638 	 */
4639 	if (tp->t_stats_gput_prev > 0)
4640 		stats_voi_update_abs_s32(tp->t_stats,
4641 					 VOI_TCP_GPUT_ND,
4642 					 ((gput - tp->t_stats_gput_prev) * 100) /
4643 					 tp->t_stats_gput_prev);
4644 #endif
4645 	tp->t_flags &= ~TF_GPUTINPROG;
4646 	tp->t_stats_gput_prev = gput;
4647 	/*
4648 	 * Now are we app limited now and there is space from where we
4649 	 * were to where we want to go?
4650 	 *
4651 	 * We don't do the other case i.e. non-applimited here since
4652 	 * the next send will trigger us picking up the missing data.
4653 	 */
4654 	if (rack->r_ctl.rc_first_appl &&
4655 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
4656 	    rack->r_ctl.rc_app_limited_cnt &&
4657 	    (SEQ_GT(rack->r_ctl.rc_first_appl->r_start, th_ack)) &&
4658 	    ((rack->r_ctl.rc_first_appl->r_end - th_ack) >
4659 	     max(rc_init_window(rack), (MIN_GP_WIN * segsiz)))) {
4660 		/*
4661 		 * Yep there is enough outstanding to make a measurement here.
4662 		 */
4663 		struct rack_sendmap *rsm, fe;
4664 
4665 		rack->r_ctl.rc_gp_lowrtt = 0xffffffff;
4666 		rack->r_ctl.rc_gp_high_rwnd = rack->rc_tp->snd_wnd;
4667 		tp->gput_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
4668 		rack->app_limited_needs_set = 0;
4669 		tp->gput_seq = th_ack;
4670 		if (rack->in_probe_rtt)
4671 			rack->measure_saw_probe_rtt = 1;
4672 		else if ((rack->measure_saw_probe_rtt) &&
4673 			 (SEQ_GEQ(tp->gput_seq, rack->r_ctl.rc_probertt_sndmax_atexit)))
4674 			rack->measure_saw_probe_rtt = 0;
4675 		if ((rack->r_ctl.rc_first_appl->r_end - th_ack) >= rack_get_measure_window(tp, rack)) {
4676 			/* There is a full window to gain info from */
4677 			tp->gput_ack = tp->gput_seq + rack_get_measure_window(tp, rack);
4678 		} else {
4679 			/* We can only measure up to the applimited point */
4680 			tp->gput_ack = tp->gput_seq + (rack->r_ctl.rc_first_appl->r_end - th_ack);
4681 			if ((tp->gput_ack - tp->gput_seq) < (MIN_GP_WIN * segsiz)) {
4682 				/*
4683 				 * We don't have enough to make a measurement.
4684 				 */
4685 				tp->t_flags &= ~TF_GPUTINPROG;
4686 				rack_log_pacing_delay_calc(rack, tp->gput_ack, tp->gput_seq,
4687 							   0, 0, 0, 6, __LINE__, NULL, quality);
4688 				return;
4689 			}
4690 		}
4691 		if (tp->t_state >= TCPS_FIN_WAIT_1) {
4692 			/*
4693 			 * We will get no more data into the SB
4694 			 * this means we need to have the data available
4695 			 * before we start a measurement.
4696 			 */
4697 			if (sbavail(&tp->t_inpcb->inp_socket->so_snd) < (tp->gput_ack - tp->gput_seq)) {
4698 				/* Nope not enough data. */
4699 				return;
4700 			}
4701 		}
4702 		tp->t_flags |= TF_GPUTINPROG;
4703 		/*
4704 		 * Now we need to find the timestamp of the send at tp->gput_seq
4705 		 * for the send based measurement.
4706 		 */
4707 		fe.r_start = tp->gput_seq;
4708 		rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
4709 		if (rsm) {
4710 			/* Ok send-based limit is set */
4711 			if (SEQ_LT(rsm->r_start, tp->gput_seq)) {
4712 				/*
4713 				 * Move back to include the earlier part
4714 				 * so our ack time lines up right (this may
4715 				 * make an overlapping measurement but thats
4716 				 * ok).
4717 				 */
4718 				tp->gput_seq = rsm->r_start;
4719 			}
4720 			if (rsm->r_flags & RACK_ACKED)
4721 				tp->gput_ts = (uint32_t)rsm->r_ack_arrival;
4722 			else
4723 				rack->app_limited_needs_set = 1;
4724 			rack->r_ctl.rc_gp_output_ts = rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
4725 		} else {
4726 			/*
4727 			 * If we don't find the rsm due to some
4728 			 * send-limit set the current time, which
4729 			 * basically disables the send-limit.
4730 			 */
4731 			struct timeval tv;
4732 
4733 			microuptime(&tv);
4734 			rack->r_ctl.rc_gp_output_ts = rack_to_usec_ts(&tv);
4735 		}
4736 		rack_log_pacing_delay_calc(rack,
4737 					   tp->gput_seq,
4738 					   tp->gput_ack,
4739 					   (uint64_t)rsm,
4740 					   tp->gput_ts,
4741 					   rack->r_ctl.rc_app_limited_cnt,
4742 					   9,
4743 					   __LINE__, NULL, quality);
4744 	}
4745 }
4746 
4747 /*
4748  * CC wrapper hook functions
4749  */
4750 static void
4751 rack_ack_received(struct tcpcb *tp, struct tcp_rack *rack, uint32_t th_ack, uint16_t nsegs,
4752     uint16_t type, int32_t recovery)
4753 {
4754 	uint32_t prior_cwnd, acked;
4755 	struct tcp_log_buffer *lgb = NULL;
4756 	uint8_t labc_to_use, quality;
4757 
4758 	INP_WLOCK_ASSERT(tp->t_inpcb);
4759 	tp->ccv->nsegs = nsegs;
4760 	acked = tp->ccv->bytes_this_ack = (th_ack - tp->snd_una);
4761 	if ((recovery) && (rack->r_ctl.rc_early_recovery_segs)) {
4762 		uint32_t max;
4763 
4764 		max = rack->r_ctl.rc_early_recovery_segs * ctf_fixed_maxseg(tp);
4765 		if (tp->ccv->bytes_this_ack > max) {
4766 			tp->ccv->bytes_this_ack = max;
4767 		}
4768 	}
4769 #ifdef STATS
4770 	stats_voi_update_abs_s32(tp->t_stats, VOI_TCP_CALCFRWINDIFF,
4771 	    ((int32_t)rack->r_ctl.cwnd_to_use) - tp->snd_wnd);
4772 #endif
4773 	quality = RACK_QUALITY_NONE;
4774 	if ((tp->t_flags & TF_GPUTINPROG) &&
4775 	    rack_enough_for_measurement(tp, rack, th_ack, &quality)) {
4776 		/* Measure the Goodput */
4777 		rack_do_goodput_measurement(tp, rack, th_ack, __LINE__, quality);
4778 #ifdef NETFLIX_PEAKRATE
4779 		if ((type == CC_ACK) &&
4780 		    (tp->t_maxpeakrate)) {
4781 			/*
4782 			 * We update t_peakrate_thr. This gives us roughly
4783 			 * one update per round trip time. Note
4784 			 * it will only be used if pace_always is off i.e
4785 			 * we don't do this for paced flows.
4786 			 */
4787 			rack_update_peakrate_thr(tp);
4788 		}
4789 #endif
4790 	}
4791 	/* Which way our we limited, if not cwnd limited no advance in CA */
4792 	if (tp->snd_cwnd <= tp->snd_wnd)
4793 		tp->ccv->flags |= CCF_CWND_LIMITED;
4794 	else
4795 		tp->ccv->flags &= ~CCF_CWND_LIMITED;
4796 	if (tp->snd_cwnd > tp->snd_ssthresh) {
4797 		tp->t_bytes_acked += min(tp->ccv->bytes_this_ack,
4798 			 nsegs * V_tcp_abc_l_var * ctf_fixed_maxseg(tp));
4799 		/* For the setting of a window past use the actual scwnd we are using */
4800 		if (tp->t_bytes_acked >= rack->r_ctl.cwnd_to_use) {
4801 			tp->t_bytes_acked -= rack->r_ctl.cwnd_to_use;
4802 			tp->ccv->flags |= CCF_ABC_SENTAWND;
4803 		}
4804 	} else {
4805 		tp->ccv->flags &= ~CCF_ABC_SENTAWND;
4806 		tp->t_bytes_acked = 0;
4807 	}
4808 	prior_cwnd = tp->snd_cwnd;
4809 	if ((recovery == 0) || (rack_max_abc_post_recovery == 0) || rack->r_use_labc_for_rec ||
4810 	    (rack_client_low_buf && (rack->client_bufferlvl < rack_client_low_buf)))
4811 		labc_to_use = rack->rc_labc;
4812 	else
4813 		labc_to_use = rack_max_abc_post_recovery;
4814 	if (rack_verbose_logging && (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
4815 		union tcp_log_stackspecific log;
4816 		struct timeval tv;
4817 
4818 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
4819 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
4820 		log.u_bbr.flex1 = th_ack;
4821 		log.u_bbr.flex2 = tp->ccv->flags;
4822 		log.u_bbr.flex3 = tp->ccv->bytes_this_ack;
4823 		log.u_bbr.flex4 = tp->ccv->nsegs;
4824 		log.u_bbr.flex5 = labc_to_use;
4825 		log.u_bbr.flex6 = prior_cwnd;
4826 		log.u_bbr.flex7 = V_tcp_do_newsack;
4827 		log.u_bbr.flex8 = 1;
4828 		lgb = tcp_log_event_(tp, NULL, NULL, NULL, BBR_LOG_CWND, 0,
4829 				     0, &log, false, NULL, NULL, 0, &tv);
4830 	}
4831 	if (CC_ALGO(tp)->ack_received != NULL) {
4832 		/* XXXLAS: Find a way to live without this */
4833 		tp->ccv->curack = th_ack;
4834 		tp->ccv->labc = labc_to_use;
4835 		tp->ccv->flags |= CCF_USE_LOCAL_ABC;
4836 		CC_ALGO(tp)->ack_received(tp->ccv, type);
4837 	}
4838 	if (lgb) {
4839 		lgb->tlb_stackinfo.u_bbr.flex6 = tp->snd_cwnd;
4840 	}
4841 	if (rack->r_must_retran) {
4842 		if (SEQ_GEQ(th_ack, rack->r_ctl.rc_snd_max_at_rto)) {
4843 			/*
4844 			 * We now are beyond the rxt point so lets disable
4845 			 * the flag.
4846 			 */
4847 			rack->r_ctl.rc_out_at_rto = 0;
4848 			rack->r_must_retran = 0;
4849 		} else if ((prior_cwnd + ctf_fixed_maxseg(tp)) <= tp->snd_cwnd) {
4850 			/*
4851 			 * Only decrement the rc_out_at_rto if the cwnd advances
4852 			 * at least a whole segment. Otherwise next time the peer
4853 			 * acks, we won't be able to send this generaly happens
4854 			 * when we are in Congestion Avoidance.
4855 			 */
4856 			if (acked <= rack->r_ctl.rc_out_at_rto){
4857 				rack->r_ctl.rc_out_at_rto -= acked;
4858 			} else {
4859 				rack->r_ctl.rc_out_at_rto = 0;
4860 			}
4861 		}
4862 	}
4863 #ifdef STATS
4864 	stats_voi_update_abs_ulong(tp->t_stats, VOI_TCP_LCWIN, rack->r_ctl.cwnd_to_use);
4865 #endif
4866 	if (rack->r_ctl.rc_rack_largest_cwnd < rack->r_ctl.cwnd_to_use) {
4867 		rack->r_ctl.rc_rack_largest_cwnd = rack->r_ctl.cwnd_to_use;
4868 	}
4869 #ifdef NETFLIX_PEAKRATE
4870 	/* we enforce max peak rate if it is set and we are not pacing */
4871 	if ((rack->rc_always_pace == 0) &&
4872 	    tp->t_peakrate_thr &&
4873 	    (tp->snd_cwnd > tp->t_peakrate_thr)) {
4874 		tp->snd_cwnd = tp->t_peakrate_thr;
4875 	}
4876 #endif
4877 }
4878 
4879 static void
4880 tcp_rack_partialack(struct tcpcb *tp)
4881 {
4882 	struct tcp_rack *rack;
4883 
4884 	rack = (struct tcp_rack *)tp->t_fb_ptr;
4885 	INP_WLOCK_ASSERT(tp->t_inpcb);
4886 	/*
4887 	 * If we are doing PRR and have enough
4888 	 * room to send <or> we are pacing and prr
4889 	 * is disabled we will want to see if we
4890 	 * can send data (by setting r_wanted_output to
4891 	 * true).
4892 	 */
4893 	if ((rack->r_ctl.rc_prr_sndcnt > 0) ||
4894 	    rack->rack_no_prr)
4895 		rack->r_wanted_output = 1;
4896 }
4897 
4898 static void
4899 rack_post_recovery(struct tcpcb *tp, uint32_t th_ack)
4900 {
4901 	struct tcp_rack *rack;
4902 	uint32_t orig_cwnd;
4903 
4904 	orig_cwnd = tp->snd_cwnd;
4905 	INP_WLOCK_ASSERT(tp->t_inpcb);
4906 	rack = (struct tcp_rack *)tp->t_fb_ptr;
4907 	/* only alert CC if we alerted when we entered */
4908 	if (CC_ALGO(tp)->post_recovery != NULL) {
4909 		tp->ccv->curack = th_ack;
4910 		CC_ALGO(tp)->post_recovery(tp->ccv);
4911 		if (tp->snd_cwnd < tp->snd_ssthresh) {
4912 			/*
4913 			 * Rack has burst control and pacing
4914 			 * so lets not set this any lower than
4915 			 * snd_ssthresh per RFC-6582 (option 2).
4916 			 */
4917 			tp->snd_cwnd = tp->snd_ssthresh;
4918 		}
4919 	}
4920 	if (rack_verbose_logging && (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
4921 		union tcp_log_stackspecific log;
4922 		struct timeval tv;
4923 
4924 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
4925 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
4926 		log.u_bbr.flex1 = th_ack;
4927 		log.u_bbr.flex2 = tp->ccv->flags;
4928 		log.u_bbr.flex3 = tp->ccv->bytes_this_ack;
4929 		log.u_bbr.flex4 = tp->ccv->nsegs;
4930 		log.u_bbr.flex5 = V_tcp_abc_l_var;
4931 		log.u_bbr.flex6 = orig_cwnd;
4932 		log.u_bbr.flex7 = V_tcp_do_newsack;
4933 		log.u_bbr.pkts_out = rack->r_ctl.rc_prr_sndcnt;
4934 		log.u_bbr.flex8 = 2;
4935 		tcp_log_event_(tp, NULL, NULL, NULL, BBR_LOG_CWND, 0,
4936 			       0, &log, false, NULL, NULL, 0, &tv);
4937 	}
4938 	if ((rack->rack_no_prr == 0) &&
4939 	    (rack->no_prr_addback == 0) &&
4940 	    (rack->r_ctl.rc_prr_sndcnt > 0)) {
4941 		/*
4942 		 * Suck the next prr cnt back into cwnd, but
4943 		 * only do that if we are not application limited.
4944 		 */
4945 		if (ctf_outstanding(tp) <= sbavail(&(tp->t_inpcb->inp_socket->so_snd))) {
4946 			/*
4947 			 * We are allowed to add back to the cwnd the amount we did
4948 			 * not get out if:
4949 			 * a) no_prr_addback is off.
4950 			 * b) we are not app limited
4951 			 * c) we are doing prr
4952 			 * <and>
4953 			 * d) it is bounded by rack_prr_addbackmax (if addback is 0, then none).
4954 			 */
4955 			tp->snd_cwnd += min((ctf_fixed_maxseg(tp) * rack_prr_addbackmax),
4956 					    rack->r_ctl.rc_prr_sndcnt);
4957 		}
4958 		rack->r_ctl.rc_prr_sndcnt = 0;
4959 		rack_log_to_prr(rack, 1, 0);
4960 	}
4961 	rack_log_to_prr(rack, 14, orig_cwnd);
4962 	tp->snd_recover = tp->snd_una;
4963 	if (rack->r_ctl.dsack_persist) {
4964 		rack->r_ctl.dsack_persist--;
4965 		if (rack->r_ctl.num_dsack && (rack->r_ctl.dsack_persist == 0)) {
4966 			rack->r_ctl.num_dsack = 0;
4967 		}
4968 		rack_log_dsack_event(rack, 1, __LINE__, 0, 0);
4969 	}
4970 	EXIT_RECOVERY(tp->t_flags);
4971 }
4972 
4973 static void
4974 rack_cong_signal(struct tcpcb *tp, uint32_t type, uint32_t ack)
4975 {
4976 	struct tcp_rack *rack;
4977 	uint32_t ssthresh_enter, cwnd_enter, in_rec_at_entry, orig_cwnd;
4978 
4979 	INP_WLOCK_ASSERT(tp->t_inpcb);
4980 #ifdef STATS
4981 	stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_CSIG, type);
4982 #endif
4983 	if (IN_RECOVERY(tp->t_flags) == 0) {
4984 		in_rec_at_entry = 0;
4985 		ssthresh_enter = tp->snd_ssthresh;
4986 		cwnd_enter = tp->snd_cwnd;
4987 	} else
4988 		in_rec_at_entry = 1;
4989 	rack = (struct tcp_rack *)tp->t_fb_ptr;
4990 	switch (type) {
4991 	case CC_NDUPACK:
4992 		tp->t_flags &= ~TF_WASFRECOVERY;
4993 		tp->t_flags &= ~TF_WASCRECOVERY;
4994 		if (!IN_FASTRECOVERY(tp->t_flags)) {
4995 			rack->r_ctl.rc_prr_delivered = 0;
4996 			rack->r_ctl.rc_prr_out = 0;
4997 			if (rack->rack_no_prr == 0) {
4998 				rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
4999 				rack_log_to_prr(rack, 2, in_rec_at_entry);
5000 			}
5001 			rack->r_ctl.rc_prr_recovery_fs = tp->snd_max - tp->snd_una;
5002 			tp->snd_recover = tp->snd_max;
5003 			if (tp->t_flags2 & TF2_ECN_PERMIT)
5004 				tp->t_flags2 |= TF2_ECN_SND_CWR;
5005 		}
5006 		break;
5007 	case CC_ECN:
5008 		if (!IN_CONGRECOVERY(tp->t_flags) ||
5009 		    /*
5010 		     * Allow ECN reaction on ACK to CWR, if
5011 		     * that data segment was also CE marked.
5012 		     */
5013 		    SEQ_GEQ(ack, tp->snd_recover)) {
5014 			EXIT_CONGRECOVERY(tp->t_flags);
5015 			KMOD_TCPSTAT_INC(tcps_ecn_rcwnd);
5016 			tp->snd_recover = tp->snd_max + 1;
5017 			if (tp->t_flags2 & TF2_ECN_PERMIT)
5018 				tp->t_flags2 |= TF2_ECN_SND_CWR;
5019 		}
5020 		break;
5021 	case CC_RTO:
5022 		tp->t_dupacks = 0;
5023 		tp->t_bytes_acked = 0;
5024 		EXIT_RECOVERY(tp->t_flags);
5025 		tp->snd_ssthresh = max(2, min(tp->snd_wnd, rack->r_ctl.cwnd_to_use) / 2 /
5026 		    ctf_fixed_maxseg(tp)) * ctf_fixed_maxseg(tp);
5027 		orig_cwnd = tp->snd_cwnd;
5028 		tp->snd_cwnd = ctf_fixed_maxseg(tp);
5029 		rack_log_to_prr(rack, 16, orig_cwnd);
5030 		if (tp->t_flags2 & TF2_ECN_PERMIT)
5031 			tp->t_flags2 |= TF2_ECN_SND_CWR;
5032 		break;
5033 	case CC_RTO_ERR:
5034 		KMOD_TCPSTAT_INC(tcps_sndrexmitbad);
5035 		/* RTO was unnecessary, so reset everything. */
5036 		tp->snd_cwnd = tp->snd_cwnd_prev;
5037 		tp->snd_ssthresh = tp->snd_ssthresh_prev;
5038 		tp->snd_recover = tp->snd_recover_prev;
5039 		if (tp->t_flags & TF_WASFRECOVERY) {
5040 			ENTER_FASTRECOVERY(tp->t_flags);
5041 			tp->t_flags &= ~TF_WASFRECOVERY;
5042 		}
5043 		if (tp->t_flags & TF_WASCRECOVERY) {
5044 			ENTER_CONGRECOVERY(tp->t_flags);
5045 			tp->t_flags &= ~TF_WASCRECOVERY;
5046 		}
5047 		tp->snd_nxt = tp->snd_max;
5048 		tp->t_badrxtwin = 0;
5049 		break;
5050 	}
5051 	if ((CC_ALGO(tp)->cong_signal != NULL)  &&
5052 	    (type != CC_RTO)){
5053 		tp->ccv->curack = ack;
5054 		CC_ALGO(tp)->cong_signal(tp->ccv, type);
5055 	}
5056 	if ((in_rec_at_entry == 0) && IN_RECOVERY(tp->t_flags)) {
5057 		rack_log_to_prr(rack, 15, cwnd_enter);
5058 		rack->r_ctl.dsack_byte_cnt = 0;
5059 		rack->r_ctl.retran_during_recovery = 0;
5060 		rack->r_ctl.rc_cwnd_at_erec = cwnd_enter;
5061 		rack->r_ctl.rc_ssthresh_at_erec = ssthresh_enter;
5062 		rack->r_ent_rec_ns = 1;
5063 	}
5064 }
5065 
5066 static inline void
5067 rack_cc_after_idle(struct tcp_rack *rack, struct tcpcb *tp)
5068 {
5069 	uint32_t i_cwnd;
5070 
5071 	INP_WLOCK_ASSERT(tp->t_inpcb);
5072 
5073 #ifdef NETFLIX_STATS
5074 	KMOD_TCPSTAT_INC(tcps_idle_restarts);
5075 	if (tp->t_state == TCPS_ESTABLISHED)
5076 		KMOD_TCPSTAT_INC(tcps_idle_estrestarts);
5077 #endif
5078 	if (CC_ALGO(tp)->after_idle != NULL)
5079 		CC_ALGO(tp)->after_idle(tp->ccv);
5080 
5081 	if (tp->snd_cwnd == 1)
5082 		i_cwnd = tp->t_maxseg;		/* SYN(-ACK) lost */
5083 	else
5084 		i_cwnd = rc_init_window(rack);
5085 
5086 	/*
5087 	 * Being idle is no differnt than the initial window. If the cc
5088 	 * clamps it down below the initial window raise it to the initial
5089 	 * window.
5090 	 */
5091 	if (tp->snd_cwnd < i_cwnd) {
5092 		tp->snd_cwnd = i_cwnd;
5093 	}
5094 }
5095 
5096 /*
5097  * Indicate whether this ack should be delayed.  We can delay the ack if
5098  * following conditions are met:
5099  *	- There is no delayed ack timer in progress.
5100  *	- Our last ack wasn't a 0-sized window. We never want to delay
5101  *	  the ack that opens up a 0-sized window.
5102  *	- LRO wasn't used for this segment. We make sure by checking that the
5103  *	  segment size is not larger than the MSS.
5104  *	- Delayed acks are enabled or this is a half-synchronized T/TCP
5105  *	  connection.
5106  */
5107 #define DELAY_ACK(tp, tlen)			 \
5108 	(((tp->t_flags & TF_RXWIN0SENT) == 0) && \
5109 	((tp->t_flags & TF_DELACK) == 0) &&	 \
5110 	(tlen <= tp->t_maxseg) &&		 \
5111 	(tp->t_delayed_ack || (tp->t_flags & TF_NEEDSYN)))
5112 
5113 static struct rack_sendmap *
5114 rack_find_lowest_rsm(struct tcp_rack *rack)
5115 {
5116 	struct rack_sendmap *rsm;
5117 
5118 	/*
5119 	 * Walk the time-order transmitted list looking for an rsm that is
5120 	 * not acked. This will be the one that was sent the longest time
5121 	 * ago that is still outstanding.
5122 	 */
5123 	TAILQ_FOREACH(rsm, &rack->r_ctl.rc_tmap, r_tnext) {
5124 		if (rsm->r_flags & RACK_ACKED) {
5125 			continue;
5126 		}
5127 		goto finish;
5128 	}
5129 finish:
5130 	return (rsm);
5131 }
5132 
5133 static struct rack_sendmap *
5134 rack_find_high_nonack(struct tcp_rack *rack, struct rack_sendmap *rsm)
5135 {
5136 	struct rack_sendmap *prsm;
5137 
5138 	/*
5139 	 * Walk the sequence order list backward until we hit and arrive at
5140 	 * the highest seq not acked. In theory when this is called it
5141 	 * should be the last segment (which it was not).
5142 	 */
5143 	counter_u64_add(rack_find_high, 1);
5144 	prsm = rsm;
5145 	RB_FOREACH_REVERSE_FROM(prsm, rack_rb_tree_head, rsm) {
5146 		if (prsm->r_flags & (RACK_ACKED | RACK_HAS_FIN)) {
5147 			continue;
5148 		}
5149 		return (prsm);
5150 	}
5151 	return (NULL);
5152 }
5153 
5154 static uint32_t
5155 rack_calc_thresh_rack(struct tcp_rack *rack, uint32_t srtt, uint32_t cts)
5156 {
5157 	int32_t lro;
5158 	uint32_t thresh;
5159 
5160 	/*
5161 	 * lro is the flag we use to determine if we have seen reordering.
5162 	 * If it gets set we have seen reordering. The reorder logic either
5163 	 * works in one of two ways:
5164 	 *
5165 	 * If reorder-fade is configured, then we track the last time we saw
5166 	 * re-ordering occur. If we reach the point where enough time as
5167 	 * passed we no longer consider reordering has occuring.
5168 	 *
5169 	 * Or if reorder-face is 0, then once we see reordering we consider
5170 	 * the connection to alway be subject to reordering and just set lro
5171 	 * to 1.
5172 	 *
5173 	 * In the end if lro is non-zero we add the extra time for
5174 	 * reordering in.
5175 	 */
5176 	if (srtt == 0)
5177 		srtt = 1;
5178 	if (rack->r_ctl.rc_reorder_ts) {
5179 		if (rack->r_ctl.rc_reorder_fade) {
5180 			if (SEQ_GEQ(cts, rack->r_ctl.rc_reorder_ts)) {
5181 				lro = cts - rack->r_ctl.rc_reorder_ts;
5182 				if (lro == 0) {
5183 					/*
5184 					 * No time as passed since the last
5185 					 * reorder, mark it as reordering.
5186 					 */
5187 					lro = 1;
5188 				}
5189 			} else {
5190 				/* Negative time? */
5191 				lro = 0;
5192 			}
5193 			if (lro > rack->r_ctl.rc_reorder_fade) {
5194 				/* Turn off reordering seen too */
5195 				rack->r_ctl.rc_reorder_ts = 0;
5196 				lro = 0;
5197 			}
5198 		} else {
5199 			/* Reodering does not fade */
5200 			lro = 1;
5201 		}
5202 	} else {
5203 		lro = 0;
5204 	}
5205 	if (rack->rc_rack_tmr_std_based == 0) {
5206 		thresh = srtt + rack->r_ctl.rc_pkt_delay;
5207 	} else {
5208 		/* Standards based pkt-delay is 1/4 srtt */
5209 		thresh = srtt +  (srtt >> 2);
5210 	}
5211 	if (lro && (rack->rc_rack_tmr_std_based == 0)) {
5212 		/* It must be set, if not you get 1/4 rtt */
5213 		if (rack->r_ctl.rc_reorder_shift)
5214 			thresh += (srtt >> rack->r_ctl.rc_reorder_shift);
5215 		else
5216 			thresh += (srtt >> 2);
5217 	}
5218 	if (rack->rc_rack_use_dsack &&
5219 	    lro &&
5220 	    (rack->r_ctl.num_dsack > 0)) {
5221 		/*
5222 		 * We only increase the reordering window if we
5223 		 * have seen reordering <and> we have a DSACK count.
5224 		 */
5225 		thresh += rack->r_ctl.num_dsack * (srtt >> 2);
5226 		rack_log_dsack_event(rack, 4, __LINE__, srtt, thresh);
5227 	}
5228 	/* SRTT * 2 is the ceiling */
5229 	if (thresh > (srtt * 2)) {
5230 		thresh = srtt * 2;
5231 	}
5232 	/* And we don't want it above the RTO max either */
5233 	if (thresh > rack_rto_max) {
5234 		thresh = rack_rto_max;
5235 	}
5236 	rack_log_dsack_event(rack, 6, __LINE__, srtt, thresh);
5237 	return (thresh);
5238 }
5239 
5240 static uint32_t
5241 rack_calc_thresh_tlp(struct tcpcb *tp, struct tcp_rack *rack,
5242 		     struct rack_sendmap *rsm, uint32_t srtt)
5243 {
5244 	struct rack_sendmap *prsm;
5245 	uint32_t thresh, len;
5246 	int segsiz;
5247 
5248 	if (srtt == 0)
5249 		srtt = 1;
5250 	if (rack->r_ctl.rc_tlp_threshold)
5251 		thresh = srtt + (srtt / rack->r_ctl.rc_tlp_threshold);
5252 	else
5253 		thresh = (srtt * 2);
5254 
5255 	/* Get the previous sent packet, if any */
5256 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
5257 	counter_u64_add(rack_enter_tlp_calc, 1);
5258 	len = rsm->r_end - rsm->r_start;
5259 	if (rack->rack_tlp_threshold_use == TLP_USE_ID) {
5260 		/* Exactly like the ID */
5261 		if (((tp->snd_max - tp->snd_una) - rack->r_ctl.rc_sacked + rack->r_ctl.rc_holes_rxt) <= segsiz) {
5262 			uint32_t alt_thresh;
5263 			/*
5264 			 * Compensate for delayed-ack with the d-ack time.
5265 			 */
5266 			counter_u64_add(rack_used_tlpmethod, 1);
5267 			alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time;
5268 			if (alt_thresh > thresh)
5269 				thresh = alt_thresh;
5270 		}
5271 	} else if (rack->rack_tlp_threshold_use == TLP_USE_TWO_ONE) {
5272 		/* 2.1 behavior */
5273 		prsm = TAILQ_PREV(rsm, rack_head, r_tnext);
5274 		if (prsm && (len <= segsiz)) {
5275 			/*
5276 			 * Two packets outstanding, thresh should be (2*srtt) +
5277 			 * possible inter-packet delay (if any).
5278 			 */
5279 			uint32_t inter_gap = 0;
5280 			int idx, nidx;
5281 
5282 			counter_u64_add(rack_used_tlpmethod, 1);
5283 			idx = rsm->r_rtr_cnt - 1;
5284 			nidx = prsm->r_rtr_cnt - 1;
5285 			if (rsm->r_tim_lastsent[nidx] >= prsm->r_tim_lastsent[idx]) {
5286 				/* Yes it was sent later (or at the same time) */
5287 				inter_gap = rsm->r_tim_lastsent[idx] - prsm->r_tim_lastsent[nidx];
5288 			}
5289 			thresh += inter_gap;
5290 		} else if (len <= segsiz) {
5291 			/*
5292 			 * Possibly compensate for delayed-ack.
5293 			 */
5294 			uint32_t alt_thresh;
5295 
5296 			counter_u64_add(rack_used_tlpmethod2, 1);
5297 			alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time;
5298 			if (alt_thresh > thresh)
5299 				thresh = alt_thresh;
5300 		}
5301 	} else if (rack->rack_tlp_threshold_use == TLP_USE_TWO_TWO) {
5302 		/* 2.2 behavior */
5303 		if (len <= segsiz) {
5304 			uint32_t alt_thresh;
5305 			/*
5306 			 * Compensate for delayed-ack with the d-ack time.
5307 			 */
5308 			counter_u64_add(rack_used_tlpmethod, 1);
5309 			alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time;
5310 			if (alt_thresh > thresh)
5311 				thresh = alt_thresh;
5312 		}
5313 	}
5314 	/* Not above an RTO */
5315 	if (thresh > tp->t_rxtcur) {
5316 		thresh = tp->t_rxtcur;
5317 	}
5318 	/* Not above a RTO max */
5319 	if (thresh > rack_rto_max) {
5320 		thresh = rack_rto_max;
5321 	}
5322 	/* Apply user supplied min TLP */
5323 	if (thresh < rack_tlp_min) {
5324 		thresh = rack_tlp_min;
5325 	}
5326 	return (thresh);
5327 }
5328 
5329 static uint32_t
5330 rack_grab_rtt(struct tcpcb *tp, struct tcp_rack *rack)
5331 {
5332 	/*
5333 	 * We want the rack_rtt which is the
5334 	 * last rtt we measured. However if that
5335 	 * does not exist we fallback to the srtt (which
5336 	 * we probably will never do) and then as a last
5337 	 * resort we use RACK_INITIAL_RTO if no srtt is
5338 	 * yet set.
5339 	 */
5340 	if (rack->rc_rack_rtt)
5341 		return (rack->rc_rack_rtt);
5342 	else if (tp->t_srtt == 0)
5343 		return (RACK_INITIAL_RTO);
5344 	return (tp->t_srtt);
5345 }
5346 
5347 static struct rack_sendmap *
5348 rack_check_recovery_mode(struct tcpcb *tp, uint32_t tsused)
5349 {
5350 	/*
5351 	 * Check to see that we don't need to fall into recovery. We will
5352 	 * need to do so if our oldest transmit is past the time we should
5353 	 * have had an ack.
5354 	 */
5355 	struct tcp_rack *rack;
5356 	struct rack_sendmap *rsm;
5357 	int32_t idx;
5358 	uint32_t srtt, thresh;
5359 
5360 	rack = (struct tcp_rack *)tp->t_fb_ptr;
5361 	if (RB_EMPTY(&rack->r_ctl.rc_mtree)) {
5362 		return (NULL);
5363 	}
5364 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
5365 	if (rsm == NULL)
5366 		return (NULL);
5367 
5368 	if (rsm->r_flags & RACK_ACKED) {
5369 		rsm = rack_find_lowest_rsm(rack);
5370 		if (rsm == NULL)
5371 			return (NULL);
5372 	}
5373 	idx = rsm->r_rtr_cnt - 1;
5374 	srtt = rack_grab_rtt(tp, rack);
5375 	thresh = rack_calc_thresh_rack(rack, srtt, tsused);
5376 	if (TSTMP_LT(tsused, ((uint32_t)rsm->r_tim_lastsent[idx]))) {
5377 		return (NULL);
5378 	}
5379 	if ((tsused - ((uint32_t)rsm->r_tim_lastsent[idx])) < thresh) {
5380 		return (NULL);
5381 	}
5382 	/* Ok if we reach here we are over-due and this guy can be sent */
5383 	if (IN_RECOVERY(tp->t_flags) == 0) {
5384 		/*
5385 		 * For the one that enters us into recovery record undo
5386 		 * info.
5387 		 */
5388 		rack->r_ctl.rc_rsm_start = rsm->r_start;
5389 		rack->r_ctl.rc_cwnd_at = tp->snd_cwnd;
5390 		rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh;
5391 	}
5392 	rack_cong_signal(tp, CC_NDUPACK, tp->snd_una);
5393 	return (rsm);
5394 }
5395 
5396 static uint32_t
5397 rack_get_persists_timer_val(struct tcpcb *tp, struct tcp_rack *rack)
5398 {
5399 	int32_t t;
5400 	int32_t tt;
5401 	uint32_t ret_val;
5402 
5403 	t = (tp->t_srtt + (tp->t_rttvar << 2));
5404 	RACK_TCPT_RANGESET(tt, t * tcp_backoff[tp->t_rxtshift],
5405  	    rack_persist_min, rack_persist_max, rack->r_ctl.timer_slop);
5406 	rack->r_ctl.rc_hpts_flags |= PACE_TMR_PERSIT;
5407 	ret_val = (uint32_t)tt;
5408 	return (ret_val);
5409 }
5410 
5411 static uint32_t
5412 rack_timer_start(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int sup_rack)
5413 {
5414 	/*
5415 	 * Start the FR timer, we do this based on getting the first one in
5416 	 * the rc_tmap. Note that if its NULL we must stop the timer. in all
5417 	 * events we need to stop the running timer (if its running) before
5418 	 * starting the new one.
5419 	 */
5420 	uint32_t thresh, exp, to, srtt, time_since_sent, tstmp_touse;
5421 	uint32_t srtt_cur;
5422 	int32_t idx;
5423 	int32_t is_tlp_timer = 0;
5424 	struct rack_sendmap *rsm;
5425 
5426 	if (rack->t_timers_stopped) {
5427 		/* All timers have been stopped none are to run */
5428 		return (0);
5429 	}
5430 	if (rack->rc_in_persist) {
5431 		/* We can't start any timer in persists */
5432 		return (rack_get_persists_timer_val(tp, rack));
5433 	}
5434 	rack->rc_on_min_to = 0;
5435 	if ((tp->t_state < TCPS_ESTABLISHED) ||
5436 	    ((tp->t_flags & TF_SACK_PERMIT) == 0)) {
5437 		goto activate_rxt;
5438 	}
5439 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
5440 	if ((rsm == NULL) || sup_rack) {
5441 		/* Nothing on the send map or no rack */
5442 activate_rxt:
5443 		time_since_sent = 0;
5444 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
5445 		if (rsm) {
5446 			/*
5447 			 * Should we discount the RTX timer any?
5448 			 *
5449 			 * We want to discount it the smallest amount.
5450 			 * If a timer (Rack/TLP or RXT) has gone off more
5451 			 * recently thats the discount we want to use (now - timer time).
5452 			 * If the retransmit of the oldest packet was more recent then
5453 			 * we want to use that (now - oldest-packet-last_transmit_time).
5454 			 *
5455 			 */
5456 			idx = rsm->r_rtr_cnt - 1;
5457 			if (TSTMP_GEQ(rack->r_ctl.rc_tlp_rxt_last_time, ((uint32_t)rsm->r_tim_lastsent[idx])))
5458 				tstmp_touse = (uint32_t)rack->r_ctl.rc_tlp_rxt_last_time;
5459 			else
5460 				tstmp_touse = (uint32_t)rsm->r_tim_lastsent[idx];
5461 			if (TSTMP_GT(cts, tstmp_touse))
5462 			    time_since_sent = cts - tstmp_touse;
5463 		}
5464 		if (SEQ_LT(tp->snd_una, tp->snd_max) || sbavail(&(tp->t_inpcb->inp_socket->so_snd))) {
5465 			rack->r_ctl.rc_hpts_flags |= PACE_TMR_RXT;
5466 			to = tp->t_rxtcur;
5467 			if (to > time_since_sent)
5468 				to -= time_since_sent;
5469 			else
5470 				to = rack->r_ctl.rc_min_to;
5471 			if (to == 0)
5472 				to = 1;
5473 			/* Special case for KEEPINIT */
5474 			if ((TCPS_HAVEESTABLISHED(tp->t_state) == 0) &&
5475 			    (TP_KEEPINIT(tp) != 0) &&
5476 			    rsm) {
5477 				/*
5478 				 * We have to put a ceiling on the rxt timer
5479 				 * of the keep-init timeout.
5480 				 */
5481 				uint32_t max_time, red;
5482 
5483 				max_time = TICKS_2_USEC(TP_KEEPINIT(tp));
5484 				if (TSTMP_GT(cts, (uint32_t)rsm->r_tim_lastsent[0])) {
5485 					red = (cts - (uint32_t)rsm->r_tim_lastsent[0]);
5486 					if (red < max_time)
5487 						max_time -= red;
5488 					else
5489 						max_time = 1;
5490 				}
5491 				/* Reduce timeout to the keep value if needed */
5492 				if (max_time < to)
5493 					to = max_time;
5494 			}
5495 			return (to);
5496 		}
5497 		return (0);
5498 	}
5499 	if (rsm->r_flags & RACK_ACKED) {
5500 		rsm = rack_find_lowest_rsm(rack);
5501 		if (rsm == NULL) {
5502 			/* No lowest? */
5503 			goto activate_rxt;
5504 		}
5505 	}
5506 	if (rack->sack_attack_disable) {
5507 		/*
5508 		 * We don't want to do
5509 		 * any TLP's if you are an attacker.
5510 		 * Though if you are doing what
5511 		 * is expected you may still have
5512 		 * SACK-PASSED marks.
5513 		 */
5514 		goto activate_rxt;
5515 	}
5516 	/* Convert from ms to usecs */
5517 	if ((rsm->r_flags & RACK_SACK_PASSED) || (rsm->r_dupack >= DUP_ACK_THRESHOLD)) {
5518 		if ((tp->t_flags & TF_SENTFIN) &&
5519 		    ((tp->snd_max - tp->snd_una) == 1) &&
5520 		    (rsm->r_flags & RACK_HAS_FIN)) {
5521 			/*
5522 			 * We don't start a rack timer if all we have is a
5523 			 * FIN outstanding.
5524 			 */
5525 			goto activate_rxt;
5526 		}
5527 		if ((rack->use_rack_rr == 0) &&
5528 		    (IN_FASTRECOVERY(tp->t_flags)) &&
5529 		    (rack->rack_no_prr == 0) &&
5530 		     (rack->r_ctl.rc_prr_sndcnt  < ctf_fixed_maxseg(tp))) {
5531 			/*
5532 			 * We are not cheating, in recovery  and
5533 			 * not enough ack's to yet get our next
5534 			 * retransmission out.
5535 			 *
5536 			 * Note that classified attackers do not
5537 			 * get to use the rack-cheat.
5538 			 */
5539 			goto activate_tlp;
5540 		}
5541 		srtt = rack_grab_rtt(tp, rack);
5542 		thresh = rack_calc_thresh_rack(rack, srtt, cts);
5543 		idx = rsm->r_rtr_cnt - 1;
5544 		exp = ((uint32_t)rsm->r_tim_lastsent[idx]) + thresh;
5545 		if (SEQ_GEQ(exp, cts)) {
5546 			to = exp - cts;
5547 			if (to < rack->r_ctl.rc_min_to) {
5548 				to = rack->r_ctl.rc_min_to;
5549 				if (rack->r_rr_config == 3)
5550 					rack->rc_on_min_to = 1;
5551 			}
5552 		} else {
5553 			to = rack->r_ctl.rc_min_to;
5554 			if (rack->r_rr_config == 3)
5555 				rack->rc_on_min_to = 1;
5556 		}
5557 	} else {
5558 		/* Ok we need to do a TLP not RACK */
5559 activate_tlp:
5560 		if ((rack->rc_tlp_in_progress != 0) &&
5561 		    (rack->r_ctl.rc_tlp_cnt_out >= rack_tlp_limit)) {
5562 			/*
5563 			 * The previous send was a TLP and we have sent
5564 			 * N TLP's without sending new data.
5565 			 */
5566 			goto activate_rxt;
5567 		}
5568 		rsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_tmap, rack_sendmap, r_tnext);
5569 		if (rsm == NULL) {
5570 			/* We found no rsm to TLP with. */
5571 			goto activate_rxt;
5572 		}
5573 		if (rsm->r_flags & RACK_HAS_FIN) {
5574 			/* If its a FIN we dont do TLP */
5575 			rsm = NULL;
5576 			goto activate_rxt;
5577 		}
5578 		idx = rsm->r_rtr_cnt - 1;
5579 		time_since_sent = 0;
5580 		if (TSTMP_GEQ(((uint32_t)rsm->r_tim_lastsent[idx]), rack->r_ctl.rc_tlp_rxt_last_time))
5581 			tstmp_touse = (uint32_t)rsm->r_tim_lastsent[idx];
5582 		else
5583 			tstmp_touse = (uint32_t)rack->r_ctl.rc_tlp_rxt_last_time;
5584 		if (TSTMP_GT(cts, tstmp_touse))
5585 		    time_since_sent = cts - tstmp_touse;
5586 		is_tlp_timer = 1;
5587 		if (tp->t_srtt) {
5588 			if ((rack->rc_srtt_measure_made == 0) &&
5589 			    (tp->t_srtt == 1)) {
5590 				/*
5591 				 * If another stack as run and set srtt to 1,
5592 				 * then the srtt was 0, so lets use the initial.
5593 				 */
5594 				srtt = RACK_INITIAL_RTO;
5595 			} else {
5596 				srtt_cur = tp->t_srtt;
5597 				srtt = srtt_cur;
5598 			}
5599 		} else
5600 			srtt = RACK_INITIAL_RTO;
5601 		/*
5602 		 * If the SRTT is not keeping up and the
5603 		 * rack RTT has spiked we want to use
5604 		 * the last RTT not the smoothed one.
5605 		 */
5606 		if (rack_tlp_use_greater &&
5607 		    tp->t_srtt &&
5608 		    (srtt < rack_grab_rtt(tp, rack))) {
5609 			srtt = rack_grab_rtt(tp, rack);
5610 		}
5611 		thresh = rack_calc_thresh_tlp(tp, rack, rsm, srtt);
5612 		if (thresh > time_since_sent) {
5613 			to = thresh - time_since_sent;
5614 		} else {
5615 			to = rack->r_ctl.rc_min_to;
5616 			rack_log_alt_to_to_cancel(rack,
5617 						  thresh,		/* flex1 */
5618 						  time_since_sent,	/* flex2 */
5619 						  tstmp_touse,		/* flex3 */
5620 						  rack->r_ctl.rc_tlp_rxt_last_time, /* flex4 */
5621 						  (uint32_t)rsm->r_tim_lastsent[idx],
5622 						  srtt,
5623 						  idx, 99);
5624 		}
5625 		if (to < rack_tlp_min) {
5626 			to = rack_tlp_min;
5627 		}
5628 		if (to > TICKS_2_USEC(TCPTV_REXMTMAX)) {
5629 			/*
5630 			 * If the TLP time works out to larger than the max
5631 			 * RTO lets not do TLP.. just RTO.
5632 			 */
5633 			goto activate_rxt;
5634 		}
5635 	}
5636 	if (is_tlp_timer == 0) {
5637 		rack->r_ctl.rc_hpts_flags |= PACE_TMR_RACK;
5638 	} else {
5639 		rack->r_ctl.rc_hpts_flags |= PACE_TMR_TLP;
5640 	}
5641 	if (to == 0)
5642 		to = 1;
5643 	return (to);
5644 }
5645 
5646 static void
5647 rack_enter_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5648 {
5649 	if (rack->rc_in_persist == 0) {
5650 		if (tp->t_flags & TF_GPUTINPROG) {
5651 			/*
5652 			 * Stop the goodput now, the calling of the
5653 			 * measurement function clears the flag.
5654 			 */
5655 			rack_do_goodput_measurement(tp, rack, tp->snd_una, __LINE__,
5656 						    RACK_QUALITY_PERSIST);
5657 		}
5658 #ifdef NETFLIX_SHARED_CWND
5659 		if (rack->r_ctl.rc_scw) {
5660 			tcp_shared_cwnd_idle(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
5661 			rack->rack_scwnd_is_idle = 1;
5662 		}
5663 #endif
5664 		rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
5665 		if (rack->r_ctl.rc_went_idle_time == 0)
5666 			rack->r_ctl.rc_went_idle_time = 1;
5667 		rack_timer_cancel(tp, rack, cts, __LINE__);
5668 		rack->r_ctl.persist_lost_ends = 0;
5669 		rack->probe_not_answered = 0;
5670 		rack->forced_ack = 0;
5671 		tp->t_rxtshift = 0;
5672 		RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
5673 			      rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
5674 		rack->rc_in_persist = 1;
5675 	}
5676 }
5677 
5678 static void
5679 rack_exit_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5680 {
5681 	if (tcp_in_hpts(rack->rc_inp)) {
5682 		tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
5683 		rack->r_ctl.rc_hpts_flags = 0;
5684 	}
5685 #ifdef NETFLIX_SHARED_CWND
5686 	if (rack->r_ctl.rc_scw) {
5687 		tcp_shared_cwnd_active(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
5688 		rack->rack_scwnd_is_idle = 0;
5689 	}
5690 #endif
5691 	if (rack->rc_gp_dyn_mul &&
5692 	    (rack->use_fixed_rate == 0) &&
5693 	    (rack->rc_always_pace)) {
5694 		/*
5695 		 * Do we count this as if a probe-rtt just
5696 		 * finished?
5697 		 */
5698 		uint32_t time_idle, idle_min;
5699 
5700 		time_idle = tcp_get_usecs(NULL) - rack->r_ctl.rc_went_idle_time;
5701 		idle_min = rack_min_probertt_hold;
5702 		if (rack_probertt_gpsrtt_cnt_div) {
5703 			uint64_t extra;
5704 			extra = (uint64_t)rack->r_ctl.rc_gp_srtt *
5705 				(uint64_t)rack_probertt_gpsrtt_cnt_mul;
5706 			extra /= (uint64_t)rack_probertt_gpsrtt_cnt_div;
5707 			idle_min += (uint32_t)extra;
5708 		}
5709 		if (time_idle >= idle_min) {
5710 			/* Yes, we count it as a probe-rtt. */
5711 			uint32_t us_cts;
5712 
5713 			us_cts = tcp_get_usecs(NULL);
5714 			if (rack->in_probe_rtt == 0) {
5715 				rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
5716 				rack->r_ctl.rc_time_probertt_entered = rack->r_ctl.rc_lower_rtt_us_cts;
5717 				rack->r_ctl.rc_time_probertt_starts = rack->r_ctl.rc_lower_rtt_us_cts;
5718 				rack->r_ctl.rc_time_of_last_probertt = rack->r_ctl.rc_lower_rtt_us_cts;
5719 			} else {
5720 				rack_exit_probertt(rack, us_cts);
5721 			}
5722 		}
5723 	}
5724 	rack->rc_in_persist = 0;
5725 	rack->r_ctl.rc_went_idle_time = 0;
5726 	tp->t_rxtshift = 0;
5727 	RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
5728 	   rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
5729 	rack->r_ctl.rc_agg_delayed = 0;
5730 	rack->r_early = 0;
5731 	rack->r_late = 0;
5732 	rack->r_ctl.rc_agg_early = 0;
5733 }
5734 
5735 static void
5736 rack_log_hpts_diag(struct tcp_rack *rack, uint32_t cts,
5737 		   struct hpts_diag *diag, struct timeval *tv)
5738 {
5739 	if (rack_verbose_logging && rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
5740 		union tcp_log_stackspecific log;
5741 
5742 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
5743 		log.u_bbr.flex1 = diag->p_nxt_slot;
5744 		log.u_bbr.flex2 = diag->p_cur_slot;
5745 		log.u_bbr.flex3 = diag->slot_req;
5746 		log.u_bbr.flex4 = diag->inp_hptsslot;
5747 		log.u_bbr.flex5 = diag->slot_remaining;
5748 		log.u_bbr.flex6 = diag->need_new_to;
5749 		log.u_bbr.flex7 = diag->p_hpts_active;
5750 		log.u_bbr.flex8 = diag->p_on_min_sleep;
5751 		/* Hijack other fields as needed */
5752 		log.u_bbr.epoch = diag->have_slept;
5753 		log.u_bbr.lt_epoch = diag->yet_to_sleep;
5754 		log.u_bbr.pkts_out = diag->co_ret;
5755 		log.u_bbr.applimited = diag->hpts_sleep_time;
5756 		log.u_bbr.delivered = diag->p_prev_slot;
5757 		log.u_bbr.inflight = diag->p_runningslot;
5758 		log.u_bbr.bw_inuse = diag->wheel_slot;
5759 		log.u_bbr.rttProp = diag->wheel_cts;
5760 		log.u_bbr.timeStamp = cts;
5761 		log.u_bbr.delRate = diag->maxslots;
5762 		log.u_bbr.cur_del_rate = diag->p_curtick;
5763 		log.u_bbr.cur_del_rate <<= 32;
5764 		log.u_bbr.cur_del_rate |= diag->p_lasttick;
5765 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
5766 		    &rack->rc_inp->inp_socket->so_rcv,
5767 		    &rack->rc_inp->inp_socket->so_snd,
5768 		    BBR_LOG_HPTSDIAG, 0,
5769 		    0, &log, false, tv);
5770 	}
5771 
5772 }
5773 
5774 static void
5775 rack_log_wakeup(struct tcpcb *tp, struct tcp_rack *rack, struct sockbuf *sb, uint32_t len, int type)
5776 {
5777 	if (rack_verbose_logging && rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
5778 		union tcp_log_stackspecific log;
5779 		struct timeval tv;
5780 
5781 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
5782 		log.u_bbr.flex1 = sb->sb_flags;
5783 		log.u_bbr.flex2 = len;
5784 		log.u_bbr.flex3 = sb->sb_state;
5785 		log.u_bbr.flex8 = type;
5786 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
5787 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
5788 		    &rack->rc_inp->inp_socket->so_rcv,
5789 		    &rack->rc_inp->inp_socket->so_snd,
5790 		    TCP_LOG_SB_WAKE, 0,
5791 		    len, &log, false, &tv);
5792 	}
5793 }
5794 
5795 static void
5796 rack_start_hpts_timer(struct tcp_rack *rack, struct tcpcb *tp, uint32_t cts,
5797       int32_t slot, uint32_t tot_len_this_send, int sup_rack)
5798 {
5799 	struct hpts_diag diag;
5800 	struct inpcb *inp;
5801 	struct timeval tv;
5802 	uint32_t delayed_ack = 0;
5803 	uint32_t hpts_timeout;
5804 	uint32_t entry_slot = slot;
5805 	uint8_t stopped;
5806 	uint32_t left = 0;
5807 	uint32_t us_cts;
5808 
5809 	inp = tp->t_inpcb;
5810 	if ((tp->t_state == TCPS_CLOSED) ||
5811 	    (tp->t_state == TCPS_LISTEN)) {
5812 		return;
5813 	}
5814 	if (tcp_in_hpts(inp)) {
5815 		/* Already on the pacer */
5816 		return;
5817 	}
5818 	stopped = rack->rc_tmr_stopped;
5819 	if (stopped && TSTMP_GT(rack->r_ctl.rc_timer_exp, cts)) {
5820 		left = rack->r_ctl.rc_timer_exp - cts;
5821 	}
5822 	rack->r_ctl.rc_timer_exp = 0;
5823 	rack->r_ctl.rc_hpts_flags = 0;
5824 	us_cts = tcp_get_usecs(&tv);
5825 	/* Now early/late accounting */
5826 	rack_log_pacing_delay_calc(rack, entry_slot, slot, 0, 0, 0, 26, __LINE__, NULL, 0);
5827 	if (rack->r_early && (rack->rc_ack_can_sendout_data == 0)) {
5828 		/*
5829 		 * We have a early carry over set,
5830 		 * we can always add more time so we
5831 		 * can always make this compensation.
5832 		 *
5833 		 * Note if ack's are allowed to wake us do not
5834 		 * penalize the next timer for being awoke
5835 		 * by an ack aka the rc_agg_early (non-paced mode).
5836 		 */
5837 		slot += rack->r_ctl.rc_agg_early;
5838 		rack->r_early = 0;
5839 		rack->r_ctl.rc_agg_early = 0;
5840 	}
5841 	if (rack->r_late) {
5842 		/*
5843 		 * This is harder, we can
5844 		 * compensate some but it
5845 		 * really depends on what
5846 		 * the current pacing time is.
5847 		 */
5848 		if (rack->r_ctl.rc_agg_delayed >= slot) {
5849 			/*
5850 			 * We can't compensate for it all.
5851 			 * And we have to have some time
5852 			 * on the clock. We always have a min
5853 			 * 10 slots (10 x 10 i.e. 100 usecs).
5854 			 */
5855 			if (slot <= HPTS_TICKS_PER_SLOT) {
5856 				/* We gain delay */
5857 				rack->r_ctl.rc_agg_delayed += (HPTS_TICKS_PER_SLOT - slot);
5858 				slot = HPTS_TICKS_PER_SLOT;
5859 			} else {
5860 				/* We take off some */
5861 				rack->r_ctl.rc_agg_delayed -= (slot - HPTS_TICKS_PER_SLOT);
5862 				slot = HPTS_TICKS_PER_SLOT;
5863 			}
5864 		} else {
5865 			slot -= rack->r_ctl.rc_agg_delayed;
5866 			rack->r_ctl.rc_agg_delayed = 0;
5867 			/* Make sure we have 100 useconds at minimum */
5868 			if (slot < HPTS_TICKS_PER_SLOT) {
5869 				rack->r_ctl.rc_agg_delayed = HPTS_TICKS_PER_SLOT - slot;
5870 				slot = HPTS_TICKS_PER_SLOT;
5871 			}
5872 			if (rack->r_ctl.rc_agg_delayed == 0)
5873 				rack->r_late = 0;
5874 		}
5875 	}
5876 	if (slot) {
5877 		/* We are pacing too */
5878 		rack->r_ctl.rc_hpts_flags |= PACE_PKT_OUTPUT;
5879 	}
5880 	hpts_timeout = rack_timer_start(tp, rack, cts, sup_rack);
5881 #ifdef NETFLIX_EXP_DETECTION
5882 	if (rack->sack_attack_disable &&
5883 	    (slot < tcp_sad_pacing_interval)) {
5884 		/*
5885 		 * We have a potential attacker on
5886 		 * the line. We have possibly some
5887 		 * (or now) pacing time set. We want to
5888 		 * slow down the processing of sacks by some
5889 		 * amount (if it is an attacker). Set the default
5890 		 * slot for attackers in place (unless the orginal
5891 		 * interval is longer). Its stored in
5892 		 * micro-seconds, so lets convert to msecs.
5893 		 */
5894 		slot = tcp_sad_pacing_interval;
5895 	}
5896 #endif
5897 	if (tp->t_flags & TF_DELACK) {
5898 		delayed_ack = TICKS_2_USEC(tcp_delacktime);
5899 		rack->r_ctl.rc_hpts_flags |= PACE_TMR_DELACK;
5900 	}
5901 	if (delayed_ack && ((hpts_timeout == 0) ||
5902 			    (delayed_ack < hpts_timeout)))
5903 		hpts_timeout = delayed_ack;
5904 	else
5905 		rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_DELACK;
5906 	/*
5907 	 * If no timers are going to run and we will fall off the hptsi
5908 	 * wheel, we resort to a keep-alive timer if its configured.
5909 	 */
5910 	if ((hpts_timeout == 0) &&
5911 	    (slot == 0)) {
5912 		if ((V_tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
5913 		    (tp->t_state <= TCPS_CLOSING)) {
5914 			/*
5915 			 * Ok we have no timer (persists, rack, tlp, rxt  or
5916 			 * del-ack), we don't have segments being paced. So
5917 			 * all that is left is the keepalive timer.
5918 			 */
5919 			if (TCPS_HAVEESTABLISHED(tp->t_state)) {
5920 				/* Get the established keep-alive time */
5921 				hpts_timeout = TICKS_2_USEC(TP_KEEPIDLE(tp));
5922 			} else {
5923 				/*
5924 				 * Get the initial setup keep-alive time,
5925 				 * note that this is probably not going to
5926 				 * happen, since rack will be running a rxt timer
5927 				 * if a SYN of some sort is outstanding. It is
5928 				 * actually handled in rack_timeout_rxt().
5929 				 */
5930 				hpts_timeout = TICKS_2_USEC(TP_KEEPINIT(tp));
5931 			}
5932 			rack->r_ctl.rc_hpts_flags |= PACE_TMR_KEEP;
5933 			if (rack->in_probe_rtt) {
5934 				/*
5935 				 * We want to instead not wake up a long time from
5936 				 * now but to wake up about the time we would
5937 				 * exit probe-rtt and initiate a keep-alive ack.
5938 				 * This will get us out of probe-rtt and update
5939 				 * our min-rtt.
5940 				 */
5941 				hpts_timeout = rack_min_probertt_hold;
5942 			}
5943 		}
5944 	}
5945 	if (left && (stopped & (PACE_TMR_KEEP | PACE_TMR_DELACK)) ==
5946 	    (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK)) {
5947 		/*
5948 		 * RACK, TLP, persists and RXT timers all are restartable
5949 		 * based on actions input .. i.e we received a packet (ack
5950 		 * or sack) and that changes things (rw, or snd_una etc).
5951 		 * Thus we can restart them with a new value. For
5952 		 * keep-alive, delayed_ack we keep track of what was left
5953 		 * and restart the timer with a smaller value.
5954 		 */
5955 		if (left < hpts_timeout)
5956 			hpts_timeout = left;
5957 	}
5958 	if (hpts_timeout) {
5959 		/*
5960 		 * Hack alert for now we can't time-out over 2,147,483
5961 		 * seconds (a bit more than 596 hours), which is probably ok
5962 		 * :).
5963 		 */
5964 		if (hpts_timeout > 0x7ffffffe)
5965 			hpts_timeout = 0x7ffffffe;
5966 		rack->r_ctl.rc_timer_exp = cts + hpts_timeout;
5967 	}
5968 	rack_log_pacing_delay_calc(rack, entry_slot, slot, hpts_timeout, 0, 0, 27, __LINE__, NULL, 0);
5969 	if ((rack->gp_ready == 0) &&
5970 	    (rack->use_fixed_rate == 0) &&
5971 	    (hpts_timeout < slot) &&
5972 	    (rack->r_ctl.rc_hpts_flags & (PACE_TMR_TLP|PACE_TMR_RXT))) {
5973 		/*
5974 		 * We have no good estimate yet for the
5975 		 * old clunky burst mitigation or the
5976 		 * real pacing. And the tlp or rxt is smaller
5977 		 * than the pacing calculation. Lets not
5978 		 * pace that long since we know the calculation
5979 		 * so far is not accurate.
5980 		 */
5981 		slot = hpts_timeout;
5982 	}
5983 	rack->r_ctl.last_pacing_time = slot;
5984 	/**
5985 	 * Turn off all the flags for queuing by default. The
5986 	 * flags have important meanings to what happens when
5987 	 * LRO interacts with the transport. Most likely (by default now)
5988 	 * mbuf_queueing and ack compression are on. So the transport
5989 	 * has a couple of flags that control what happens (if those
5990 	 * are not on then these flags won't have any effect since it
5991 	 * won't go through the queuing LRO path).
5992 	 *
5993 	 * INP_MBUF_QUEUE_READY - This flags says that I am busy
5994 	 *                        pacing output, so don't disturb. But
5995 	 *                        it also means LRO can wake me if there
5996 	 *                        is a SACK arrival.
5997 	 *
5998 	 * INP_DONT_SACK_QUEUE - This flag is used in conjunction
5999 	 *                       with the above flag (QUEUE_READY) and
6000 	 *                       when present it says don't even wake me
6001 	 *                       if a SACK arrives.
6002 	 *
6003 	 * The idea behind these flags is that if we are pacing we
6004 	 * set the MBUF_QUEUE_READY and only get woken up if
6005 	 * a SACK arrives (which could change things) or if
6006 	 * our pacing timer expires. If, however, we have a rack
6007 	 * timer running, then we don't even want a sack to wake
6008 	 * us since the rack timer has to expire before we can send.
6009 	 *
6010 	 * Other cases should usually have none of the flags set
6011 	 * so LRO can call into us.
6012 	 */
6013 	inp->inp_flags2 &= ~(INP_DONT_SACK_QUEUE|INP_MBUF_QUEUE_READY);
6014 	if (slot) {
6015 		rack->r_ctl.rc_last_output_to = us_cts + slot;
6016 		/*
6017 		 * A pacing timer (slot) is being set, in
6018 		 * such a case we cannot send (we are blocked by
6019 		 * the timer). So lets tell LRO that it should not
6020 		 * wake us unless there is a SACK. Note this only
6021 		 * will be effective if mbuf queueing is on or
6022 		 * compressed acks are being processed.
6023 		 */
6024 		inp->inp_flags2 |= INP_MBUF_QUEUE_READY;
6025 		/*
6026 		 * But wait if we have a Rack timer running
6027 		 * even a SACK should not disturb us (with
6028 		 * the exception of r_rr_config 3).
6029 		 */
6030 		if ((rack->r_ctl.rc_hpts_flags & PACE_TMR_RACK) &&
6031 		    (rack->r_rr_config != 3))
6032 			inp->inp_flags2 |= INP_DONT_SACK_QUEUE;
6033 		if (rack->rc_ack_can_sendout_data) {
6034 			/*
6035 			 * Ahh but wait, this is that special case
6036 			 * where the pacing timer can be disturbed
6037 			 * backout the changes (used for non-paced
6038 			 * burst limiting).
6039 			 */
6040 			inp->inp_flags2 &= ~(INP_DONT_SACK_QUEUE|INP_MBUF_QUEUE_READY);
6041 		}
6042 		if ((rack->use_rack_rr) &&
6043 		    (rack->r_rr_config < 2) &&
6044 		    ((hpts_timeout) && (hpts_timeout < slot))) {
6045 			/*
6046 			 * Arrange for the hpts to kick back in after the
6047 			 * t-o if the t-o does not cause a send.
6048 			 */
6049 			(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_USEC_TO_SLOTS(hpts_timeout),
6050 						   __LINE__, &diag);
6051 			rack_log_hpts_diag(rack, us_cts, &diag, &tv);
6052 			rack_log_to_start(rack, cts, hpts_timeout, slot, 0);
6053 		} else {
6054 			(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_USEC_TO_SLOTS(slot),
6055 						   __LINE__, &diag);
6056 			rack_log_hpts_diag(rack, us_cts, &diag, &tv);
6057 			rack_log_to_start(rack, cts, hpts_timeout, slot, 1);
6058 		}
6059 	} else if (hpts_timeout) {
6060 		/*
6061 		 * With respect to inp_flags2 here, lets let any new acks wake
6062 		 * us up here. Since we are not pacing (no pacing timer), output
6063 		 * can happen so we should let it. If its a Rack timer, then any inbound
6064 		 * packet probably won't change the sending (we will be blocked)
6065 		 * but it may change the prr stats so letting it in (the set defaults
6066 		 * at the start of this block) are good enough.
6067 		 */
6068 		(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_USEC_TO_SLOTS(hpts_timeout),
6069 					   __LINE__, &diag);
6070 		rack_log_hpts_diag(rack, us_cts, &diag, &tv);
6071 		rack_log_to_start(rack, cts, hpts_timeout, slot, 0);
6072 	} else {
6073 		/* No timer starting */
6074 #ifdef INVARIANTS
6075 		if (SEQ_GT(tp->snd_max, tp->snd_una)) {
6076 			panic("tp:%p rack:%p tlts:%d cts:%u slot:%u pto:%u -- no timer started?",
6077 			    tp, rack, tot_len_this_send, cts, slot, hpts_timeout);
6078 		}
6079 #endif
6080 	}
6081 	rack->rc_tmr_stopped = 0;
6082 	if (slot)
6083 		rack_log_type_bbrsnd(rack, tot_len_this_send, slot, us_cts, &tv);
6084 }
6085 
6086 /*
6087  * RACK Timer, here we simply do logging and house keeping.
6088  * the normal rack_output() function will call the
6089  * appropriate thing to check if we need to do a RACK retransmit.
6090  * We return 1, saying don't proceed with rack_output only
6091  * when all timers have been stopped (destroyed PCB?).
6092  */
6093 static int
6094 rack_timeout_rack(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
6095 {
6096 	/*
6097 	 * This timer simply provides an internal trigger to send out data.
6098 	 * The check_recovery_mode call will see if there are needed
6099 	 * retransmissions, if so we will enter fast-recovery. The output
6100 	 * call may or may not do the same thing depending on sysctl
6101 	 * settings.
6102 	 */
6103 	struct rack_sendmap *rsm;
6104 
6105 	if (tp->t_timers->tt_flags & TT_STOPPED) {
6106 		return (1);
6107 	}
6108 	counter_u64_add(rack_to_tot, 1);
6109 	if (rack->r_state && (rack->r_state != tp->t_state))
6110 		rack_set_state(tp, rack);
6111 	rack->rc_on_min_to = 0;
6112 	rsm = rack_check_recovery_mode(tp, cts);
6113 	rack_log_to_event(rack, RACK_TO_FRM_RACK, rsm);
6114 	if (rsm) {
6115 		rack->r_ctl.rc_resend = rsm;
6116 		rack->r_timer_override = 1;
6117 		if (rack->use_rack_rr) {
6118 			/*
6119 			 * Don't accumulate extra pacing delay
6120 			 * we are allowing the rack timer to
6121 			 * over-ride pacing i.e. rrr takes precedence
6122 			 * if the pacing interval is longer than the rrr
6123 			 * time (in other words we get the min pacing
6124 			 * time versus rrr pacing time).
6125 			 */
6126 			rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
6127 		}
6128 	}
6129 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_RACK;
6130 	if (rsm == NULL) {
6131 		/* restart a timer and return 1 */
6132 		rack_start_hpts_timer(rack, tp, cts,
6133 				      0, 0, 0);
6134 		return (1);
6135 	}
6136 	return (0);
6137 }
6138 
6139 static void
6140 rack_adjust_orig_mlen(struct rack_sendmap *rsm)
6141 {
6142 	if (rsm->m->m_len > rsm->orig_m_len) {
6143 		/*
6144 		 * Mbuf grew, caused by sbcompress, our offset does
6145 		 * not change.
6146 		 */
6147 		rsm->orig_m_len = rsm->m->m_len;
6148 	} else if (rsm->m->m_len < rsm->orig_m_len) {
6149 		/*
6150 		 * Mbuf shrank, trimmed off the top by an ack, our
6151 		 * offset changes.
6152 		 */
6153 		rsm->soff -= (rsm->orig_m_len - rsm->m->m_len);
6154 		rsm->orig_m_len = rsm->m->m_len;
6155 	}
6156 }
6157 
6158 static void
6159 rack_setup_offset_for_rsm(struct rack_sendmap *src_rsm, struct rack_sendmap *rsm)
6160 {
6161 	struct mbuf *m;
6162 	uint32_t soff;
6163 
6164 	if (src_rsm->m && (src_rsm->orig_m_len != src_rsm->m->m_len)) {
6165 		/* Fix up the orig_m_len and possibly the mbuf offset */
6166 		rack_adjust_orig_mlen(src_rsm);
6167 	}
6168 	m = src_rsm->m;
6169 	soff = src_rsm->soff + (src_rsm->r_end - src_rsm->r_start);
6170 	while (soff >= m->m_len) {
6171 		/* Move out past this mbuf */
6172 		soff -= m->m_len;
6173 		m = m->m_next;
6174 		KASSERT((m != NULL),
6175 			("rsm:%p nrsm:%p hit at soff:%u null m",
6176 			 src_rsm, rsm, soff));
6177 	}
6178 	rsm->m = m;
6179 	rsm->soff = soff;
6180 	rsm->orig_m_len = m->m_len;
6181 }
6182 
6183 static __inline void
6184 rack_clone_rsm(struct tcp_rack *rack, struct rack_sendmap *nrsm,
6185 	       struct rack_sendmap *rsm, uint32_t start)
6186 {
6187 	int idx;
6188 
6189 	nrsm->r_start = start;
6190 	nrsm->r_end = rsm->r_end;
6191 	nrsm->r_rtr_cnt = rsm->r_rtr_cnt;
6192 	nrsm->r_flags = rsm->r_flags;
6193 	nrsm->r_dupack = rsm->r_dupack;
6194 	nrsm->r_no_rtt_allowed = rsm->r_no_rtt_allowed;
6195 	nrsm->r_rtr_bytes = 0;
6196 	nrsm->r_fas = rsm->r_fas;
6197 	rsm->r_end = nrsm->r_start;
6198 	nrsm->r_just_ret = rsm->r_just_ret;
6199 	for (idx = 0; idx < nrsm->r_rtr_cnt; idx++) {
6200 		nrsm->r_tim_lastsent[idx] = rsm->r_tim_lastsent[idx];
6201 	}
6202 	/* Now if we have SYN flag we keep it on the left edge */
6203 	if (nrsm->r_flags & RACK_HAS_SYN)
6204 		nrsm->r_flags &= ~RACK_HAS_SYN;
6205 	/* Now if we have a FIN flag we keep it on the right edge */
6206 	if (rsm->r_flags & RACK_HAS_FIN)
6207 		rsm->r_flags &= ~RACK_HAS_FIN;
6208 	/* Push bit must go to the right edge as well */
6209 	if (rsm->r_flags & RACK_HAD_PUSH)
6210 		rsm->r_flags &= ~RACK_HAD_PUSH;
6211 	/* Clone over the state of the hw_tls flag */
6212 	nrsm->r_hw_tls = rsm->r_hw_tls;
6213 	/*
6214 	 * Now we need to find nrsm's new location in the mbuf chain
6215 	 * we basically calculate a new offset, which is soff +
6216 	 * how much is left in original rsm. Then we walk out the mbuf
6217 	 * chain to find the righ postion, it may be the same mbuf
6218 	 * or maybe not.
6219 	 */
6220 	KASSERT(((rsm->m != NULL) ||
6221 		 (rsm->r_flags & (RACK_HAS_SYN|RACK_HAS_FIN))),
6222 		("rsm:%p nrsm:%p rack:%p -- rsm->m is NULL?", rsm, nrsm, rack));
6223 	if (rsm->m)
6224 		rack_setup_offset_for_rsm(rsm, nrsm);
6225 }
6226 
6227 static struct rack_sendmap *
6228 rack_merge_rsm(struct tcp_rack *rack,
6229 	       struct rack_sendmap *l_rsm,
6230 	       struct rack_sendmap *r_rsm)
6231 {
6232 	/*
6233 	 * We are merging two ack'd RSM's,
6234 	 * the l_rsm is on the left (lower seq
6235 	 * values) and the r_rsm is on the right
6236 	 * (higher seq value). The simplest way
6237 	 * to merge these is to move the right
6238 	 * one into the left. I don't think there
6239 	 * is any reason we need to try to find
6240 	 * the oldest (or last oldest retransmitted).
6241 	 */
6242 	struct rack_sendmap *rm;
6243 
6244 	rack_log_map_chg(rack->rc_tp, rack, NULL,
6245 			 l_rsm, r_rsm, MAP_MERGE, r_rsm->r_end, __LINE__);
6246 	l_rsm->r_end = r_rsm->r_end;
6247 	if (l_rsm->r_dupack < r_rsm->r_dupack)
6248 		l_rsm->r_dupack = r_rsm->r_dupack;
6249 	if (r_rsm->r_rtr_bytes)
6250 		l_rsm->r_rtr_bytes += r_rsm->r_rtr_bytes;
6251 	if (r_rsm->r_in_tmap) {
6252 		/* This really should not happen */
6253 		TAILQ_REMOVE(&rack->r_ctl.rc_tmap, r_rsm, r_tnext);
6254 		r_rsm->r_in_tmap = 0;
6255 	}
6256 
6257 	/* Now the flags */
6258 	if (r_rsm->r_flags & RACK_HAS_FIN)
6259 		l_rsm->r_flags |= RACK_HAS_FIN;
6260 	if (r_rsm->r_flags & RACK_TLP)
6261 		l_rsm->r_flags |= RACK_TLP;
6262 	if (r_rsm->r_flags & RACK_RWND_COLLAPSED)
6263 		l_rsm->r_flags |= RACK_RWND_COLLAPSED;
6264 	if ((r_rsm->r_flags & RACK_APP_LIMITED)  &&
6265 	    ((l_rsm->r_flags & RACK_APP_LIMITED) == 0)) {
6266 		/*
6267 		 * If both are app-limited then let the
6268 		 * free lower the count. If right is app
6269 		 * limited and left is not, transfer.
6270 		 */
6271 		l_rsm->r_flags |= RACK_APP_LIMITED;
6272 		r_rsm->r_flags &= ~RACK_APP_LIMITED;
6273 		if (r_rsm == rack->r_ctl.rc_first_appl)
6274 			rack->r_ctl.rc_first_appl = l_rsm;
6275 	}
6276 	rm = RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, r_rsm);
6277 #ifdef INVARIANTS
6278 	if (rm != r_rsm) {
6279 		panic("removing head in rack:%p rsm:%p rm:%p",
6280 		      rack, r_rsm, rm);
6281 	}
6282 #endif
6283 	if ((r_rsm->r_limit_type == 0) && (l_rsm->r_limit_type != 0)) {
6284 		/* Transfer the split limit to the map we free */
6285 		r_rsm->r_limit_type = l_rsm->r_limit_type;
6286 		l_rsm->r_limit_type = 0;
6287 	}
6288 	rack_free(rack, r_rsm);
6289 	return (l_rsm);
6290 }
6291 
6292 /*
6293  * TLP Timer, here we simply setup what segment we want to
6294  * have the TLP expire on, the normal rack_output() will then
6295  * send it out.
6296  *
6297  * We return 1, saying don't proceed with rack_output only
6298  * when all timers have been stopped (destroyed PCB?).
6299  */
6300 static int
6301 rack_timeout_tlp(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, uint8_t *doing_tlp)
6302 {
6303 	/*
6304 	 * Tail Loss Probe.
6305 	 */
6306 	struct rack_sendmap *rsm = NULL;
6307 	struct rack_sendmap *insret;
6308 	struct socket *so;
6309 	uint32_t amm;
6310 	uint32_t out, avail;
6311 	int collapsed_win = 0;
6312 
6313 	if (tp->t_timers->tt_flags & TT_STOPPED) {
6314 		return (1);
6315 	}
6316 	if (TSTMP_LT(cts, rack->r_ctl.rc_timer_exp)) {
6317 		/* Its not time yet */
6318 		return (0);
6319 	}
6320 	if (ctf_progress_timeout_check(tp, true)) {
6321 		rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
6322 		tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
6323 		return (1);
6324 	}
6325 	/*
6326 	 * A TLP timer has expired. We have been idle for 2 rtts. So we now
6327 	 * need to figure out how to force a full MSS segment out.
6328 	 */
6329 	rack_log_to_event(rack, RACK_TO_FRM_TLP, NULL);
6330 	rack->r_ctl.retran_during_recovery = 0;
6331 	rack->r_ctl.dsack_byte_cnt = 0;
6332 	counter_u64_add(rack_tlp_tot, 1);
6333 	if (rack->r_state && (rack->r_state != tp->t_state))
6334 		rack_set_state(tp, rack);
6335 	so = tp->t_inpcb->inp_socket;
6336 	avail = sbavail(&so->so_snd);
6337 	out = tp->snd_max - tp->snd_una;
6338 	if (out > tp->snd_wnd) {
6339 		/* special case, we need a retransmission */
6340 		collapsed_win = 1;
6341 		goto need_retran;
6342 	}
6343 	if (rack->r_ctl.dsack_persist && (rack->r_ctl.rc_tlp_cnt_out >= 1)) {
6344 		rack->r_ctl.dsack_persist--;
6345 		if (rack->r_ctl.num_dsack && (rack->r_ctl.dsack_persist == 0)) {
6346 			rack->r_ctl.num_dsack = 0;
6347 		}
6348 		rack_log_dsack_event(rack, 1, __LINE__, 0, 0);
6349 	}
6350 	if ((tp->t_flags & TF_GPUTINPROG) &&
6351 	    (rack->r_ctl.rc_tlp_cnt_out == 1)) {
6352 		/*
6353 		 * If this is the second in a row
6354 		 * TLP and we are doing a measurement
6355 		 * its time to abandon the measurement.
6356 		 * Something is likely broken on
6357 		 * the clients network and measuring a
6358 		 * broken network does us no good.
6359 		 */
6360 		tp->t_flags &= ~TF_GPUTINPROG;
6361 		rack_log_pacing_delay_calc(rack, (tp->gput_ack - tp->gput_seq) /*flex2*/,
6362 					   rack->r_ctl.rc_gp_srtt /*flex1*/,
6363 					   tp->gput_seq,
6364 					   0, 0, 18, __LINE__, NULL, 0);
6365 	}
6366 	/*
6367 	 * Check our send oldest always settings, and if
6368 	 * there is an oldest to send jump to the need_retran.
6369 	 */
6370 	if (rack_always_send_oldest && (TAILQ_EMPTY(&rack->r_ctl.rc_tmap) == 0))
6371 		goto need_retran;
6372 
6373 	if (avail > out) {
6374 		/* New data is available */
6375 		amm = avail - out;
6376 		if (amm > ctf_fixed_maxseg(tp)) {
6377 			amm = ctf_fixed_maxseg(tp);
6378 			if ((amm + out) > tp->snd_wnd) {
6379 				/* We are rwnd limited */
6380 				goto need_retran;
6381 			}
6382 		} else if (amm < ctf_fixed_maxseg(tp)) {
6383 			/* not enough to fill a MTU */
6384 			goto need_retran;
6385 		}
6386 		if (IN_FASTRECOVERY(tp->t_flags)) {
6387 			/* Unlikely */
6388 			if (rack->rack_no_prr == 0) {
6389 				if (out + amm <= tp->snd_wnd) {
6390 					rack->r_ctl.rc_prr_sndcnt = amm;
6391 					rack->r_ctl.rc_tlp_new_data = amm;
6392 					rack_log_to_prr(rack, 4, 0);
6393 				}
6394 			} else
6395 				goto need_retran;
6396 		} else {
6397 			/* Set the send-new override */
6398 			if (out + amm <= tp->snd_wnd)
6399 				rack->r_ctl.rc_tlp_new_data = amm;
6400 			else
6401 				goto need_retran;
6402 		}
6403 		rack->r_ctl.rc_tlpsend = NULL;
6404 		counter_u64_add(rack_tlp_newdata, 1);
6405 		goto send;
6406 	}
6407 need_retran:
6408 	/*
6409 	 * Ok we need to arrange the last un-acked segment to be re-sent, or
6410 	 * optionally the first un-acked segment.
6411 	 */
6412 	if (collapsed_win == 0) {
6413 		if (rack_always_send_oldest)
6414 			rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
6415 		else {
6416 			rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
6417 			if (rsm && (rsm->r_flags & (RACK_ACKED | RACK_HAS_FIN))) {
6418 				rsm = rack_find_high_nonack(rack, rsm);
6419 			}
6420 		}
6421 		if (rsm == NULL) {
6422 			counter_u64_add(rack_tlp_does_nada, 1);
6423 #ifdef TCP_BLACKBOX
6424 			tcp_log_dump_tp_logbuf(tp, "nada counter trips", M_NOWAIT, true);
6425 #endif
6426 			goto out;
6427 		}
6428 	} else {
6429 		/*
6430 		 * We must find the last segment
6431 		 * that was acceptable by the client.
6432 		 */
6433 		RB_FOREACH_REVERSE(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
6434 			if ((rsm->r_flags & RACK_RWND_COLLAPSED) == 0) {
6435 				/* Found one */
6436 				break;
6437 			}
6438 		}
6439 		if (rsm == NULL) {
6440 			/* None? if so send the first */
6441 			rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
6442 			if (rsm == NULL) {
6443 				counter_u64_add(rack_tlp_does_nada, 1);
6444 #ifdef TCP_BLACKBOX
6445 				tcp_log_dump_tp_logbuf(tp, "nada counter trips", M_NOWAIT, true);
6446 #endif
6447 				goto out;
6448 			}
6449 		}
6450 	}
6451 	if ((rsm->r_end - rsm->r_start) > ctf_fixed_maxseg(tp)) {
6452 		/*
6453 		 * We need to split this the last segment in two.
6454 		 */
6455 		struct rack_sendmap *nrsm;
6456 
6457 		nrsm = rack_alloc_full_limit(rack);
6458 		if (nrsm == NULL) {
6459 			/*
6460 			 * No memory to split, we will just exit and punt
6461 			 * off to the RXT timer.
6462 			 */
6463 			counter_u64_add(rack_tlp_does_nada, 1);
6464 			goto out;
6465 		}
6466 		rack_clone_rsm(rack, nrsm, rsm,
6467 			       (rsm->r_end - ctf_fixed_maxseg(tp)));
6468 		rack_log_map_chg(tp, rack, NULL, rsm, nrsm, MAP_SPLIT, 0, __LINE__);
6469 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
6470 #ifdef INVARIANTS
6471 		if (insret != NULL) {
6472 			panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
6473 			      nrsm, insret, rack, rsm);
6474 		}
6475 #endif
6476 		if (rsm->r_in_tmap) {
6477 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
6478 			nrsm->r_in_tmap = 1;
6479 		}
6480 		rsm = nrsm;
6481 	}
6482 	rack->r_ctl.rc_tlpsend = rsm;
6483 send:
6484 	/* Make sure output path knows we are doing a TLP */
6485 	*doing_tlp = 1;
6486 	rack->r_timer_override = 1;
6487 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_TLP;
6488 	return (0);
6489 out:
6490 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_TLP;
6491 	return (0);
6492 }
6493 
6494 /*
6495  * Delayed ack Timer, here we simply need to setup the
6496  * ACK_NOW flag and remove the DELACK flag. From there
6497  * the output routine will send the ack out.
6498  *
6499  * We only return 1, saying don't proceed, if all timers
6500  * are stopped (destroyed PCB?).
6501  */
6502 static int
6503 rack_timeout_delack(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
6504 {
6505 	if (tp->t_timers->tt_flags & TT_STOPPED) {
6506 		return (1);
6507 	}
6508 	rack_log_to_event(rack, RACK_TO_FRM_DELACK, NULL);
6509 	tp->t_flags &= ~TF_DELACK;
6510 	tp->t_flags |= TF_ACKNOW;
6511 	KMOD_TCPSTAT_INC(tcps_delack);
6512 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_DELACK;
6513 	return (0);
6514 }
6515 
6516 /*
6517  * Persists timer, here we simply send the
6518  * same thing as a keepalive will.
6519  * the one byte send.
6520  *
6521  * We only return 1, saying don't proceed, if all timers
6522  * are stopped (destroyed PCB?).
6523  */
6524 static int
6525 rack_timeout_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
6526 {
6527 	struct tcptemp *t_template;
6528 	struct inpcb *inp;
6529 	int32_t retval = 1;
6530 
6531 	inp = tp->t_inpcb;
6532 
6533 	if (tp->t_timers->tt_flags & TT_STOPPED) {
6534 		return (1);
6535 	}
6536 	if (rack->rc_in_persist == 0)
6537 		return (0);
6538 	if (ctf_progress_timeout_check(tp, false)) {
6539 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
6540 		rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
6541 		tcp_set_inp_to_drop(inp, ETIMEDOUT);
6542 		counter_u64_add(rack_persists_lost_ends, rack->r_ctl.persist_lost_ends);
6543 		return (1);
6544 	}
6545 	KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
6546 	/*
6547 	 * Persistence timer into zero window. Force a byte to be output, if
6548 	 * possible.
6549 	 */
6550 	KMOD_TCPSTAT_INC(tcps_persisttimeo);
6551 	/*
6552 	 * Hack: if the peer is dead/unreachable, we do not time out if the
6553 	 * window is closed.  After a full backoff, drop the connection if
6554 	 * the idle time (no responses to probes) reaches the maximum
6555 	 * backoff that we would use if retransmitting.
6556 	 */
6557 	if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
6558 	    (ticks - tp->t_rcvtime >= tcp_maxpersistidle ||
6559 	     TICKS_2_USEC(ticks - tp->t_rcvtime) >= RACK_REXMTVAL(tp) * tcp_totbackoff)) {
6560 		KMOD_TCPSTAT_INC(tcps_persistdrop);
6561 		retval = 1;
6562 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
6563 		tcp_set_inp_to_drop(rack->rc_inp, ETIMEDOUT);
6564 		counter_u64_add(rack_persists_lost_ends, rack->r_ctl.persist_lost_ends);
6565 		goto out;
6566 	}
6567 	if ((sbavail(&rack->rc_inp->inp_socket->so_snd) == 0) &&
6568 	    tp->snd_una == tp->snd_max)
6569 		rack_exit_persist(tp, rack, cts);
6570 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_PERSIT;
6571 	/*
6572 	 * If the user has closed the socket then drop a persisting
6573 	 * connection after a much reduced timeout.
6574 	 */
6575 	if (tp->t_state > TCPS_CLOSE_WAIT &&
6576 	    (ticks - tp->t_rcvtime) >= TCPTV_PERSMAX) {
6577 		retval = 1;
6578 		KMOD_TCPSTAT_INC(tcps_persistdrop);
6579 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
6580 		tcp_set_inp_to_drop(rack->rc_inp, ETIMEDOUT);
6581 		counter_u64_add(rack_persists_lost_ends, rack->r_ctl.persist_lost_ends);
6582 		goto out;
6583 	}
6584 	t_template = tcpip_maketemplate(rack->rc_inp);
6585 	if (t_template) {
6586 		/* only set it if we were answered */
6587 		if (rack->forced_ack == 0) {
6588 			rack->forced_ack = 1;
6589 			rack->r_ctl.forced_ack_ts = tcp_get_usecs(NULL);
6590 		} else {
6591 			rack->probe_not_answered = 1;
6592 			counter_u64_add(rack_persists_loss, 1);
6593 			rack->r_ctl.persist_lost_ends++;
6594 		}
6595 		counter_u64_add(rack_persists_sends, 1);
6596 		tcp_respond(tp, t_template->tt_ipgen,
6597 			    &t_template->tt_t, (struct mbuf *)NULL,
6598 			    tp->rcv_nxt, tp->snd_una - 1, 0);
6599 		/* This sends an ack */
6600 		if (tp->t_flags & TF_DELACK)
6601 			tp->t_flags &= ~TF_DELACK;
6602 		free(t_template, M_TEMP);
6603 	}
6604 	if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
6605 		tp->t_rxtshift++;
6606 out:
6607 	rack_log_to_event(rack, RACK_TO_FRM_PERSIST, NULL);
6608 	rack_start_hpts_timer(rack, tp, cts,
6609 			      0, 0, 0);
6610 	return (retval);
6611 }
6612 
6613 /*
6614  * If a keepalive goes off, we had no other timers
6615  * happening. We always return 1 here since this
6616  * routine either drops the connection or sends
6617  * out a segment with respond.
6618  */
6619 static int
6620 rack_timeout_keepalive(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
6621 {
6622 	struct tcptemp *t_template;
6623 	struct inpcb *inp;
6624 
6625 	if (tp->t_timers->tt_flags & TT_STOPPED) {
6626 		return (1);
6627 	}
6628 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_KEEP;
6629 	inp = tp->t_inpcb;
6630 	rack_log_to_event(rack, RACK_TO_FRM_KEEP, NULL);
6631 	/*
6632 	 * Keep-alive timer went off; send something or drop connection if
6633 	 * idle for too long.
6634 	 */
6635 	KMOD_TCPSTAT_INC(tcps_keeptimeo);
6636 	if (tp->t_state < TCPS_ESTABLISHED)
6637 		goto dropit;
6638 	if ((V_tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
6639 	    tp->t_state <= TCPS_CLOSING) {
6640 		if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp))
6641 			goto dropit;
6642 		/*
6643 		 * Send a packet designed to force a response if the peer is
6644 		 * up and reachable: either an ACK if the connection is
6645 		 * still alive, or an RST if the peer has closed the
6646 		 * connection due to timeout or reboot. Using sequence
6647 		 * number tp->snd_una-1 causes the transmitted zero-length
6648 		 * segment to lie outside the receive window; by the
6649 		 * protocol spec, this requires the correspondent TCP to
6650 		 * respond.
6651 		 */
6652 		KMOD_TCPSTAT_INC(tcps_keepprobe);
6653 		t_template = tcpip_maketemplate(inp);
6654 		if (t_template) {
6655 			if (rack->forced_ack == 0) {
6656 				rack->forced_ack = 1;
6657 				rack->r_ctl.forced_ack_ts = tcp_get_usecs(NULL);
6658 			} else {
6659 				rack->probe_not_answered = 1;
6660 			}
6661 			tcp_respond(tp, t_template->tt_ipgen,
6662 			    &t_template->tt_t, (struct mbuf *)NULL,
6663 			    tp->rcv_nxt, tp->snd_una - 1, 0);
6664 			free(t_template, M_TEMP);
6665 		}
6666 	}
6667 	rack_start_hpts_timer(rack, tp, cts, 0, 0, 0);
6668 	return (1);
6669 dropit:
6670 	KMOD_TCPSTAT_INC(tcps_keepdrops);
6671 	tcp_log_end_status(tp, TCP_EI_STATUS_KEEP_MAX);
6672 	tcp_set_inp_to_drop(rack->rc_inp, ETIMEDOUT);
6673 	return (1);
6674 }
6675 
6676 /*
6677  * Retransmit helper function, clear up all the ack
6678  * flags and take care of important book keeping.
6679  */
6680 static void
6681 rack_remxt_tmr(struct tcpcb *tp)
6682 {
6683 	/*
6684 	 * The retransmit timer went off, all sack'd blocks must be
6685 	 * un-acked.
6686 	 */
6687 	struct rack_sendmap *rsm, *trsm = NULL;
6688 	struct tcp_rack *rack;
6689 
6690 	rack = (struct tcp_rack *)tp->t_fb_ptr;
6691 	rack_timer_cancel(tp, rack, tcp_get_usecs(NULL), __LINE__);
6692 	rack_log_to_event(rack, RACK_TO_FRM_TMR, NULL);
6693 	if (rack->r_state && (rack->r_state != tp->t_state))
6694 		rack_set_state(tp, rack);
6695 	/*
6696 	 * Ideally we would like to be able to
6697 	 * mark SACK-PASS on anything not acked here.
6698 	 *
6699 	 * However, if we do that we would burst out
6700 	 * all that data 1ms apart. This would be unwise,
6701 	 * so for now we will just let the normal rxt timer
6702 	 * and tlp timer take care of it.
6703 	 *
6704 	 * Also we really need to stick them back in sequence
6705 	 * order. This way we send in the proper order and any
6706 	 * sacks that come floating in will "re-ack" the data.
6707 	 * To do this we zap the tmap with an INIT and then
6708 	 * walk through and place every rsm in the RB tree
6709 	 * back in its seq ordered place.
6710 	 */
6711 	TAILQ_INIT(&rack->r_ctl.rc_tmap);
6712 	RB_FOREACH(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
6713 		rsm->r_dupack = 0;
6714 		rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
6715 		/* We must re-add it back to the tlist */
6716 		if (trsm == NULL) {
6717 			TAILQ_INSERT_HEAD(&rack->r_ctl.rc_tmap, rsm, r_tnext);
6718 		} else {
6719 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, trsm, rsm, r_tnext);
6720 		}
6721 		rsm->r_in_tmap = 1;
6722 		trsm = rsm;
6723 		if (rsm->r_flags & RACK_ACKED)
6724 			rsm->r_flags |= RACK_WAS_ACKED;
6725 		rsm->r_flags &= ~(RACK_ACKED | RACK_SACK_PASSED | RACK_WAS_SACKPASS);
6726 		rsm->r_flags |= RACK_MUST_RXT;
6727 	}
6728 	/* Clear the count (we just un-acked them) */
6729 	rack->r_ctl.rc_last_timeout_snduna = tp->snd_una;
6730 	rack->r_ctl.rc_sacked = 0;
6731 	rack->r_ctl.rc_sacklast = NULL;
6732 	rack->r_ctl.rc_agg_delayed = 0;
6733 	rack->r_early = 0;
6734 	rack->r_ctl.rc_agg_early = 0;
6735 	rack->r_late = 0;
6736 	/* Clear the tlp rtx mark */
6737 	rack->r_ctl.rc_resend = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
6738 	if (rack->r_ctl.rc_resend != NULL)
6739 		rack->r_ctl.rc_resend->r_flags |= RACK_TO_REXT;
6740 	rack->r_ctl.rc_prr_sndcnt = 0;
6741 	rack_log_to_prr(rack, 6, 0);
6742 	rack->r_timer_override = 1;
6743 	if ((((tp->t_flags & TF_SACK_PERMIT) == 0)
6744 #ifdef NETFLIX_EXP_DETECTION
6745 	    || (rack->sack_attack_disable != 0)
6746 #endif
6747 		    ) && ((tp->t_flags & TF_SENTFIN) == 0)) {
6748 		/*
6749 		 * For non-sack customers new data
6750 		 * needs to go out as retransmits until
6751 		 * we retransmit up to snd_max.
6752 		 */
6753 		rack->r_must_retran = 1;
6754 		rack->r_ctl.rc_out_at_rto = ctf_flight_size(rack->rc_tp,
6755 						rack->r_ctl.rc_sacked);
6756 	}
6757 	rack->r_ctl.rc_snd_max_at_rto = tp->snd_max;
6758 }
6759 
6760 static void
6761 rack_convert_rtts(struct tcpcb *tp)
6762 {
6763 	if (tp->t_srtt > 1) {
6764 		uint32_t val, frac;
6765 
6766 		val = tp->t_srtt >> TCP_RTT_SHIFT;
6767 		frac = tp->t_srtt & 0x1f;
6768 		tp->t_srtt = TICKS_2_USEC(val);
6769 		/*
6770 		 * frac is the fractional part of the srtt (if any)
6771 		 * but its in ticks and every bit represents
6772 		 * 1/32nd of a hz.
6773 		 */
6774 		if (frac) {
6775 			if (hz == 1000) {
6776 				frac = (((uint64_t)frac * (uint64_t)HPTS_USEC_IN_MSEC) / (uint64_t)TCP_RTT_SCALE);
6777 			} else {
6778 				frac = (((uint64_t)frac * (uint64_t)HPTS_USEC_IN_SEC) / ((uint64_t)(hz) * (uint64_t)TCP_RTT_SCALE));
6779 			}
6780 			tp->t_srtt += frac;
6781 		}
6782 	}
6783 	if (tp->t_rttvar) {
6784 		uint32_t val, frac;
6785 
6786 		val = tp->t_rttvar >> TCP_RTTVAR_SHIFT;
6787 		frac = tp->t_rttvar & 0x1f;
6788 		tp->t_rttvar = TICKS_2_USEC(val);
6789 		/*
6790 		 * frac is the fractional part of the srtt (if any)
6791 		 * but its in ticks and every bit represents
6792 		 * 1/32nd of a hz.
6793 		 */
6794 		if (frac) {
6795 			if (hz == 1000) {
6796 				frac = (((uint64_t)frac * (uint64_t)HPTS_USEC_IN_MSEC) / (uint64_t)TCP_RTT_SCALE);
6797 			} else {
6798 				frac = (((uint64_t)frac * (uint64_t)HPTS_USEC_IN_SEC) / ((uint64_t)(hz) * (uint64_t)TCP_RTT_SCALE));
6799 			}
6800 			tp->t_rttvar += frac;
6801 		}
6802 	}
6803 	tp->t_rxtcur = RACK_REXMTVAL(tp);
6804 	if (TCPS_HAVEESTABLISHED(tp->t_state)) {
6805 		tp->t_rxtcur += TICKS_2_USEC(tcp_rexmit_slop);
6806 	}
6807 	if (tp->t_rxtcur > rack_rto_max) {
6808 		tp->t_rxtcur = rack_rto_max;
6809 	}
6810 }
6811 
6812 static void
6813 rack_cc_conn_init(struct tcpcb *tp)
6814 {
6815 	struct tcp_rack *rack;
6816 	uint32_t srtt;
6817 
6818 	rack = (struct tcp_rack *)tp->t_fb_ptr;
6819 	srtt = tp->t_srtt;
6820 	cc_conn_init(tp);
6821 	/*
6822 	 * Now convert to rack's internal format,
6823 	 * if required.
6824 	 */
6825 	if ((srtt == 0) && (tp->t_srtt != 0))
6826 		rack_convert_rtts(tp);
6827 	/*
6828 	 * We want a chance to stay in slowstart as
6829 	 * we create a connection. TCP spec says that
6830 	 * initially ssthresh is infinite. For our
6831 	 * purposes that is the snd_wnd.
6832 	 */
6833 	if (tp->snd_ssthresh < tp->snd_wnd) {
6834 		tp->snd_ssthresh = tp->snd_wnd;
6835 	}
6836 	/*
6837 	 * We also want to assure a IW worth of
6838 	 * data can get inflight.
6839 	 */
6840 	if (rc_init_window(rack) < tp->snd_cwnd)
6841 		tp->snd_cwnd = rc_init_window(rack);
6842 }
6843 
6844 /*
6845  * Re-transmit timeout! If we drop the PCB we will return 1, otherwise
6846  * we will setup to retransmit the lowest seq number outstanding.
6847  */
6848 static int
6849 rack_timeout_rxt(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
6850 {
6851 	int32_t rexmt;
6852 	struct inpcb *inp;
6853 	int32_t retval = 0;
6854 	bool isipv6;
6855 
6856 	inp = tp->t_inpcb;
6857 	if (tp->t_timers->tt_flags & TT_STOPPED) {
6858 		return (1);
6859 	}
6860 	if ((tp->t_flags & TF_GPUTINPROG) &&
6861 	    (tp->t_rxtshift)) {
6862 		/*
6863 		 * We have had a second timeout
6864 		 * measurements on successive rxt's are not profitable.
6865 		 * It is unlikely to be of any use (the network is
6866 		 * broken or the client went away).
6867 		 */
6868 		tp->t_flags &= ~TF_GPUTINPROG;
6869 		rack_log_pacing_delay_calc(rack, (tp->gput_ack - tp->gput_seq) /*flex2*/,
6870 					   rack->r_ctl.rc_gp_srtt /*flex1*/,
6871 					   tp->gput_seq,
6872 					   0, 0, 18, __LINE__, NULL, 0);
6873 	}
6874 	if (ctf_progress_timeout_check(tp, false)) {
6875 		tcp_log_end_status(tp, TCP_EI_STATUS_RETRAN);
6876 		rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
6877 		tcp_set_inp_to_drop(inp, ETIMEDOUT);
6878 		return (1);
6879 	}
6880 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_RXT;
6881 	rack->r_ctl.retran_during_recovery = 0;
6882 	rack->r_ctl.dsack_byte_cnt = 0;
6883 	if (IN_FASTRECOVERY(tp->t_flags))
6884 		tp->t_flags |= TF_WASFRECOVERY;
6885 	else
6886 		tp->t_flags &= ~TF_WASFRECOVERY;
6887 	if (IN_CONGRECOVERY(tp->t_flags))
6888 		tp->t_flags |= TF_WASCRECOVERY;
6889 	else
6890 		tp->t_flags &= ~TF_WASCRECOVERY;
6891 	if (TCPS_HAVEESTABLISHED(tp->t_state) &&
6892 	    (tp->snd_una == tp->snd_max)) {
6893 		/* Nothing outstanding .. nothing to do */
6894 		return (0);
6895 	}
6896 	if (rack->r_ctl.dsack_persist) {
6897 		rack->r_ctl.dsack_persist--;
6898 		if (rack->r_ctl.num_dsack && (rack->r_ctl.dsack_persist == 0)) {
6899 			rack->r_ctl.num_dsack = 0;
6900 		}
6901 		rack_log_dsack_event(rack, 1, __LINE__, 0, 0);
6902 	}
6903 	/*
6904 	 * Rack can only run one timer  at a time, so we cannot
6905 	 * run a KEEPINIT (gating SYN sending) and a retransmit
6906 	 * timer for the SYN. So if we are in a front state and
6907 	 * have a KEEPINIT timer we need to check the first transmit
6908 	 * against now to see if we have exceeded the KEEPINIT time
6909 	 * (if one is set).
6910 	 */
6911 	if ((TCPS_HAVEESTABLISHED(tp->t_state) == 0) &&
6912 	    (TP_KEEPINIT(tp) != 0)) {
6913 		struct rack_sendmap *rsm;
6914 
6915 		rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
6916 		if (rsm) {
6917 			/* Ok we have something outstanding to test keepinit with */
6918 			if ((TSTMP_GT(cts, (uint32_t)rsm->r_tim_lastsent[0])) &&
6919 			    ((cts - (uint32_t)rsm->r_tim_lastsent[0]) >= TICKS_2_USEC(TP_KEEPINIT(tp)))) {
6920 				/* We have exceeded the KEEPINIT time */
6921 				tcp_log_end_status(tp, TCP_EI_STATUS_KEEP_MAX);
6922 				goto drop_it;
6923 			}
6924 		}
6925 	}
6926 	/*
6927 	 * Retransmission timer went off.  Message has not been acked within
6928 	 * retransmit interval.  Back off to a longer retransmit interval
6929 	 * and retransmit one segment.
6930 	 */
6931 	rack_remxt_tmr(tp);
6932 	if ((rack->r_ctl.rc_resend == NULL) ||
6933 	    ((rack->r_ctl.rc_resend->r_flags & RACK_RWND_COLLAPSED) == 0)) {
6934 		/*
6935 		 * If the rwnd collapsed on
6936 		 * the one we are retransmitting
6937 		 * it does not count against the
6938 		 * rxt count.
6939 		 */
6940 		tp->t_rxtshift++;
6941 	}
6942 	if (tp->t_rxtshift > TCP_MAXRXTSHIFT) {
6943 		tcp_log_end_status(tp, TCP_EI_STATUS_RETRAN);
6944 drop_it:
6945 		tp->t_rxtshift = TCP_MAXRXTSHIFT;
6946 		KMOD_TCPSTAT_INC(tcps_timeoutdrop);
6947 		retval = 1;
6948 		tcp_set_inp_to_drop(rack->rc_inp,
6949 		    (tp->t_softerror ? (uint16_t) tp->t_softerror : ETIMEDOUT));
6950 		goto out;
6951 	}
6952 	if (tp->t_state == TCPS_SYN_SENT) {
6953 		/*
6954 		 * If the SYN was retransmitted, indicate CWND to be limited
6955 		 * to 1 segment in cc_conn_init().
6956 		 */
6957 		tp->snd_cwnd = 1;
6958 	} else if (tp->t_rxtshift == 1) {
6959 		/*
6960 		 * first retransmit; record ssthresh and cwnd so they can be
6961 		 * recovered if this turns out to be a "bad" retransmit. A
6962 		 * retransmit is considered "bad" if an ACK for this segment
6963 		 * is received within RTT/2 interval; the assumption here is
6964 		 * that the ACK was already in flight.  See "On Estimating
6965 		 * End-to-End Network Path Properties" by Allman and Paxson
6966 		 * for more details.
6967 		 */
6968 		tp->snd_cwnd_prev = tp->snd_cwnd;
6969 		tp->snd_ssthresh_prev = tp->snd_ssthresh;
6970 		tp->snd_recover_prev = tp->snd_recover;
6971 		tp->t_badrxtwin = ticks + (USEC_2_TICKS(tp->t_srtt)/2);
6972 		tp->t_flags |= TF_PREVVALID;
6973 	} else if ((tp->t_flags & TF_RCVD_TSTMP) == 0)
6974 		tp->t_flags &= ~TF_PREVVALID;
6975 	KMOD_TCPSTAT_INC(tcps_rexmttimeo);
6976 	if ((tp->t_state == TCPS_SYN_SENT) ||
6977 	    (tp->t_state == TCPS_SYN_RECEIVED))
6978 		rexmt = RACK_INITIAL_RTO * tcp_backoff[tp->t_rxtshift];
6979 	else
6980 		rexmt = max(rack_rto_min, (tp->t_srtt + (tp->t_rttvar << 2))) * tcp_backoff[tp->t_rxtshift];
6981 
6982 	RACK_TCPT_RANGESET(tp->t_rxtcur, rexmt,
6983 	   max(rack_rto_min, rexmt), rack_rto_max, rack->r_ctl.timer_slop);
6984 	/*
6985 	 * We enter the path for PLMTUD if connection is established or, if
6986 	 * connection is FIN_WAIT_1 status, reason for the last is that if
6987 	 * amount of data we send is very small, we could send it in couple
6988 	 * of packets and process straight to FIN. In that case we won't
6989 	 * catch ESTABLISHED state.
6990 	 */
6991 #ifdef INET6
6992 	isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) ? true : false;
6993 #else
6994 	isipv6 = false;
6995 #endif
6996 	if (((V_tcp_pmtud_blackhole_detect == 1) ||
6997 	    (V_tcp_pmtud_blackhole_detect == 2 && !isipv6) ||
6998 	    (V_tcp_pmtud_blackhole_detect == 3 && isipv6)) &&
6999 	    ((tp->t_state == TCPS_ESTABLISHED) ||
7000 	    (tp->t_state == TCPS_FIN_WAIT_1))) {
7001 		/*
7002 		 * Idea here is that at each stage of mtu probe (usually,
7003 		 * 1448 -> 1188 -> 524) should be given 2 chances to recover
7004 		 * before further clamping down. 'tp->t_rxtshift % 2 == 0'
7005 		 * should take care of that.
7006 		 */
7007 		if (((tp->t_flags2 & (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) ==
7008 		    (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) &&
7009 		    (tp->t_rxtshift >= 2 && tp->t_rxtshift < 6 &&
7010 		    tp->t_rxtshift % 2 == 0)) {
7011 			/*
7012 			 * Enter Path MTU Black-hole Detection mechanism: -
7013 			 * Disable Path MTU Discovery (IP "DF" bit). -
7014 			 * Reduce MTU to lower value than what we negotiated
7015 			 * with peer.
7016 			 */
7017 			if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) == 0) {
7018 				/* Record that we may have found a black hole. */
7019 				tp->t_flags2 |= TF2_PLPMTU_BLACKHOLE;
7020 				/* Keep track of previous MSS. */
7021 				tp->t_pmtud_saved_maxseg = tp->t_maxseg;
7022 			}
7023 
7024 			/*
7025 			 * Reduce the MSS to blackhole value or to the
7026 			 * default in an attempt to retransmit.
7027 			 */
7028 #ifdef INET6
7029 			if (isipv6 &&
7030 			    tp->t_maxseg > V_tcp_v6pmtud_blackhole_mss) {
7031 				/* Use the sysctl tuneable blackhole MSS. */
7032 				tp->t_maxseg = V_tcp_v6pmtud_blackhole_mss;
7033 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated);
7034 			} else if (isipv6) {
7035 				/* Use the default MSS. */
7036 				tp->t_maxseg = V_tcp_v6mssdflt;
7037 				/*
7038 				 * Disable Path MTU Discovery when we switch
7039 				 * to minmss.
7040 				 */
7041 				tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
7042 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
7043 			}
7044 #endif
7045 #if defined(INET6) && defined(INET)
7046 			else
7047 #endif
7048 #ifdef INET
7049 			if (tp->t_maxseg > V_tcp_pmtud_blackhole_mss) {
7050 				/* Use the sysctl tuneable blackhole MSS. */
7051 				tp->t_maxseg = V_tcp_pmtud_blackhole_mss;
7052 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated);
7053 			} else {
7054 				/* Use the default MSS. */
7055 				tp->t_maxseg = V_tcp_mssdflt;
7056 				/*
7057 				 * Disable Path MTU Discovery when we switch
7058 				 * to minmss.
7059 				 */
7060 				tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
7061 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
7062 			}
7063 #endif
7064 		} else {
7065 			/*
7066 			 * If further retransmissions are still unsuccessful
7067 			 * with a lowered MTU, maybe this isn't a blackhole
7068 			 * and we restore the previous MSS and blackhole
7069 			 * detection flags. The limit '6' is determined by
7070 			 * giving each probe stage (1448, 1188, 524) 2
7071 			 * chances to recover.
7072 			 */
7073 			if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) &&
7074 			    (tp->t_rxtshift >= 6)) {
7075 				tp->t_flags2 |= TF2_PLPMTU_PMTUD;
7076 				tp->t_flags2 &= ~TF2_PLPMTU_BLACKHOLE;
7077 				tp->t_maxseg = tp->t_pmtud_saved_maxseg;
7078 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_failed);
7079 			}
7080 		}
7081 	}
7082 	/*
7083 	 * Disable RFC1323 and SACK if we haven't got any response to
7084 	 * our third SYN to work-around some broken terminal servers
7085 	 * (most of which have hopefully been retired) that have bad VJ
7086 	 * header compression code which trashes TCP segments containing
7087 	 * unknown-to-them TCP options.
7088 	 */
7089 	if (tcp_rexmit_drop_options && (tp->t_state == TCPS_SYN_SENT) &&
7090 	    (tp->t_rxtshift == 3))
7091 		tp->t_flags &= ~(TF_REQ_SCALE|TF_REQ_TSTMP|TF_SACK_PERMIT);
7092 	/*
7093 	 * If we backed off this far, our srtt estimate is probably bogus.
7094 	 * Clobber it so we'll take the next rtt measurement as our srtt;
7095 	 * move the current srtt into rttvar to keep the current retransmit
7096 	 * times until then.
7097 	 */
7098 	if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
7099 #ifdef INET6
7100 		if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
7101 			in6_losing(tp->t_inpcb);
7102 		else
7103 #endif
7104 			in_losing(tp->t_inpcb);
7105 		tp->t_rttvar += tp->t_srtt;
7106 		tp->t_srtt = 0;
7107 	}
7108 	sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
7109 	tp->snd_recover = tp->snd_max;
7110 	tp->t_flags |= TF_ACKNOW;
7111 	tp->t_rtttime = 0;
7112 	rack_cong_signal(tp, CC_RTO, tp->snd_una);
7113 out:
7114 	return (retval);
7115 }
7116 
7117 static int
7118 rack_process_timers(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, uint8_t hpts_calling, uint8_t *doing_tlp)
7119 {
7120 	int32_t ret = 0;
7121 	int32_t timers = (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK);
7122 
7123 	if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
7124 	    (tp->t_flags & TF_GPUTINPROG)) {
7125 		/*
7126 		 * We have a goodput in progress
7127 		 * and we have entered a late state.
7128 		 * Do we have enough data in the sb
7129 		 * to handle the GPUT request?
7130 		 */
7131 		uint32_t bytes;
7132 
7133 		bytes = tp->gput_ack - tp->gput_seq;
7134 		if (SEQ_GT(tp->gput_seq, tp->snd_una))
7135 			bytes += tp->gput_seq - tp->snd_una;
7136 		if (bytes > sbavail(&tp->t_inpcb->inp_socket->so_snd)) {
7137 			/*
7138 			 * There are not enough bytes in the socket
7139 			 * buffer that have been sent to cover this
7140 			 * measurement. Cancel it.
7141 			 */
7142 			rack_log_pacing_delay_calc(rack, (tp->gput_ack - tp->gput_seq) /*flex2*/,
7143 						   rack->r_ctl.rc_gp_srtt /*flex1*/,
7144 						   tp->gput_seq,
7145 						   0, 0, 18, __LINE__, NULL, 0);
7146 			tp->t_flags &= ~TF_GPUTINPROG;
7147 		}
7148 	}
7149 	if (timers == 0) {
7150 		return (0);
7151 	}
7152 	if (tp->t_state == TCPS_LISTEN) {
7153 		/* no timers on listen sockets */
7154 		if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)
7155 			return (0);
7156 		return (1);
7157 	}
7158 	if ((timers & PACE_TMR_RACK) &&
7159 	    rack->rc_on_min_to) {
7160 		/*
7161 		 * For the rack timer when we
7162 		 * are on a min-timeout (which means rrr_conf = 3)
7163 		 * we don't want to check the timer. It may
7164 		 * be going off for a pace and thats ok we
7165 		 * want to send the retransmit (if its ready).
7166 		 *
7167 		 * If its on a normal rack timer (non-min) then
7168 		 * we will check if its expired.
7169 		 */
7170 		goto skip_time_check;
7171 	}
7172 	if (TSTMP_LT(cts, rack->r_ctl.rc_timer_exp)) {
7173 		uint32_t left;
7174 
7175 		if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
7176 			ret = -1;
7177 			rack_log_to_processing(rack, cts, ret, 0);
7178 			return (0);
7179 		}
7180 		if (hpts_calling == 0) {
7181 			/*
7182 			 * A user send or queued mbuf (sack) has called us? We
7183 			 * return 0 and let the pacing guards
7184 			 * deal with it if they should or
7185 			 * should not cause a send.
7186 			 */
7187 			ret = -2;
7188 			rack_log_to_processing(rack, cts, ret, 0);
7189 			return (0);
7190 		}
7191 		/*
7192 		 * Ok our timer went off early and we are not paced false
7193 		 * alarm, go back to sleep.
7194 		 */
7195 		ret = -3;
7196 		left = rack->r_ctl.rc_timer_exp - cts;
7197 		tcp_hpts_insert(tp->t_inpcb, HPTS_MS_TO_SLOTS(left));
7198 		rack_log_to_processing(rack, cts, ret, left);
7199 		return (1);
7200 	}
7201 skip_time_check:
7202 	rack->rc_tmr_stopped = 0;
7203 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_MASK;
7204 	if (timers & PACE_TMR_DELACK) {
7205 		ret = rack_timeout_delack(tp, rack, cts);
7206 	} else if (timers & PACE_TMR_RACK) {
7207 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
7208 		rack->r_fast_output = 0;
7209 		ret = rack_timeout_rack(tp, rack, cts);
7210 	} else if (timers & PACE_TMR_TLP) {
7211 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
7212 		ret = rack_timeout_tlp(tp, rack, cts, doing_tlp);
7213 	} else if (timers & PACE_TMR_RXT) {
7214 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
7215 		rack->r_fast_output = 0;
7216 		ret = rack_timeout_rxt(tp, rack, cts);
7217 	} else if (timers & PACE_TMR_PERSIT) {
7218 		ret = rack_timeout_persist(tp, rack, cts);
7219 	} else if (timers & PACE_TMR_KEEP) {
7220 		ret = rack_timeout_keepalive(tp, rack, cts);
7221 	}
7222 	rack_log_to_processing(rack, cts, ret, timers);
7223 	return (ret);
7224 }
7225 
7226 static void
7227 rack_timer_cancel(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int line)
7228 {
7229 	struct timeval tv;
7230 	uint32_t us_cts, flags_on_entry;
7231 	uint8_t hpts_removed = 0;
7232 
7233 	flags_on_entry = rack->r_ctl.rc_hpts_flags;
7234 	us_cts = tcp_get_usecs(&tv);
7235 	if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
7236 	    ((TSTMP_GEQ(us_cts, rack->r_ctl.rc_last_output_to)) ||
7237 	     ((tp->snd_max - tp->snd_una) == 0))) {
7238 		tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
7239 		hpts_removed = 1;
7240 		/* If we were not delayed cancel out the flag. */
7241 		if ((tp->snd_max - tp->snd_una) == 0)
7242 			rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
7243 		rack_log_to_cancel(rack, hpts_removed, line, us_cts, &tv, flags_on_entry);
7244 	}
7245 	if (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) {
7246 		rack->rc_tmr_stopped = rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK;
7247 		if (tcp_in_hpts(rack->rc_inp) &&
7248 		    ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0)) {
7249 			/*
7250 			 * Canceling timer's when we have no output being
7251 			 * paced. We also must remove ourselves from the
7252 			 * hpts.
7253 			 */
7254 			tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
7255 			hpts_removed = 1;
7256 		}
7257 		rack->r_ctl.rc_hpts_flags &= ~(PACE_TMR_MASK);
7258 	}
7259 	if (hpts_removed == 0)
7260 		rack_log_to_cancel(rack, hpts_removed, line, us_cts, &tv, flags_on_entry);
7261 }
7262 
7263 static void
7264 rack_timer_stop(struct tcpcb *tp, uint32_t timer_type)
7265 {
7266 	return;
7267 }
7268 
7269 static int
7270 rack_stopall(struct tcpcb *tp)
7271 {
7272 	struct tcp_rack *rack;
7273 	rack = (struct tcp_rack *)tp->t_fb_ptr;
7274 	rack->t_timers_stopped = 1;
7275 	return (0);
7276 }
7277 
7278 static void
7279 rack_timer_activate(struct tcpcb *tp, uint32_t timer_type, uint32_t delta)
7280 {
7281 	return;
7282 }
7283 
7284 static int
7285 rack_timer_active(struct tcpcb *tp, uint32_t timer_type)
7286 {
7287 	return (0);
7288 }
7289 
7290 static void
7291 rack_stop_all_timers(struct tcpcb *tp)
7292 {
7293 	struct tcp_rack *rack;
7294 
7295 	/*
7296 	 * Assure no timers are running.
7297 	 */
7298 	if (tcp_timer_active(tp, TT_PERSIST)) {
7299 		/* We enter in persists, set the flag appropriately */
7300 		rack = (struct tcp_rack *)tp->t_fb_ptr;
7301 		rack->rc_in_persist = 1;
7302 	}
7303 	tcp_timer_suspend(tp, TT_PERSIST);
7304 	tcp_timer_suspend(tp, TT_REXMT);
7305 	tcp_timer_suspend(tp, TT_KEEP);
7306 	tcp_timer_suspend(tp, TT_DELACK);
7307 }
7308 
7309 static void
7310 rack_update_rsm(struct tcpcb *tp, struct tcp_rack *rack,
7311     struct rack_sendmap *rsm, uint64_t ts, uint16_t add_flag)
7312 {
7313 	int32_t idx;
7314 
7315 	rsm->r_rtr_cnt++;
7316 	rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
7317 	rsm->r_dupack = 0;
7318 	if (rsm->r_rtr_cnt > RACK_NUM_OF_RETRANS) {
7319 		rsm->r_rtr_cnt = RACK_NUM_OF_RETRANS;
7320 		rsm->r_flags |= RACK_OVERMAX;
7321 	}
7322 	if ((rsm->r_rtr_cnt > 1) && ((rsm->r_flags & RACK_TLP) == 0)) {
7323 		rack->r_ctl.rc_holes_rxt += (rsm->r_end - rsm->r_start);
7324 		rsm->r_rtr_bytes += (rsm->r_end - rsm->r_start);
7325 	}
7326 	idx = rsm->r_rtr_cnt - 1;
7327 	rsm->r_tim_lastsent[idx] = ts;
7328 	/*
7329 	 * Here we don't add in the len of send, since its already
7330 	 * in snduna <->snd_max.
7331 	 */
7332 	rsm->r_fas = ctf_flight_size(rack->rc_tp,
7333 				     rack->r_ctl.rc_sacked);
7334 	if (rsm->r_flags & RACK_ACKED) {
7335 		/* Problably MTU discovery messing with us */
7336 		rsm->r_flags &= ~RACK_ACKED;
7337 		rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
7338 	}
7339 	if (rsm->r_in_tmap) {
7340 		TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7341 		rsm->r_in_tmap = 0;
7342 	}
7343 	TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7344 	rsm->r_in_tmap = 1;
7345 	if (rsm->r_flags & RACK_SACK_PASSED) {
7346 		/* We have retransmitted due to the SACK pass */
7347 		rsm->r_flags &= ~RACK_SACK_PASSED;
7348 		rsm->r_flags |= RACK_WAS_SACKPASS;
7349 	}
7350 }
7351 
7352 static uint32_t
7353 rack_update_entry(struct tcpcb *tp, struct tcp_rack *rack,
7354     struct rack_sendmap *rsm, uint64_t ts, int32_t *lenp, uint16_t add_flag)
7355 {
7356 	/*
7357 	 * We (re-)transmitted starting at rsm->r_start for some length
7358 	 * (possibly less than r_end.
7359 	 */
7360 	struct rack_sendmap *nrsm, *insret;
7361 	uint32_t c_end;
7362 	int32_t len;
7363 
7364 	len = *lenp;
7365 	c_end = rsm->r_start + len;
7366 	if (SEQ_GEQ(c_end, rsm->r_end)) {
7367 		/*
7368 		 * We retransmitted the whole piece or more than the whole
7369 		 * slopping into the next rsm.
7370 		 */
7371 		rack_update_rsm(tp, rack, rsm, ts, add_flag);
7372 		if (c_end == rsm->r_end) {
7373 			*lenp = 0;
7374 			return (0);
7375 		} else {
7376 			int32_t act_len;
7377 
7378 			/* Hangs over the end return whats left */
7379 			act_len = rsm->r_end - rsm->r_start;
7380 			*lenp = (len - act_len);
7381 			return (rsm->r_end);
7382 		}
7383 		/* We don't get out of this block. */
7384 	}
7385 	/*
7386 	 * Here we retransmitted less than the whole thing which means we
7387 	 * have to split this into what was transmitted and what was not.
7388 	 */
7389 	nrsm = rack_alloc_full_limit(rack);
7390 	if (nrsm == NULL) {
7391 		/*
7392 		 * We can't get memory, so lets not proceed.
7393 		 */
7394 		*lenp = 0;
7395 		return (0);
7396 	}
7397 	/*
7398 	 * So here we are going to take the original rsm and make it what we
7399 	 * retransmitted. nrsm will be the tail portion we did not
7400 	 * retransmit. For example say the chunk was 1, 11 (10 bytes). And
7401 	 * we retransmitted 5 bytes i.e. 1, 5. The original piece shrinks to
7402 	 * 1, 6 and the new piece will be 6, 11.
7403 	 */
7404 	rack_clone_rsm(rack, nrsm, rsm, c_end);
7405 	nrsm->r_dupack = 0;
7406 	rack_log_retran_reason(rack, nrsm, __LINE__, 0, 2);
7407 	insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
7408 #ifdef INVARIANTS
7409 	if (insret != NULL) {
7410 		panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
7411 		      nrsm, insret, rack, rsm);
7412 	}
7413 #endif
7414 	if (rsm->r_in_tmap) {
7415 		TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
7416 		nrsm->r_in_tmap = 1;
7417 	}
7418 	rsm->r_flags &= (~RACK_HAS_FIN);
7419 	rack_update_rsm(tp, rack, rsm, ts, add_flag);
7420 	/* Log a split of rsm into rsm and nrsm */
7421 	rack_log_map_chg(tp, rack, NULL, rsm, nrsm, MAP_SPLIT, 0, __LINE__);
7422 	*lenp = 0;
7423 	return (0);
7424 }
7425 
7426 static void
7427 rack_log_output(struct tcpcb *tp, struct tcpopt *to, int32_t len,
7428 		uint32_t seq_out, uint8_t th_flags, int32_t err, uint64_t cts,
7429 		struct rack_sendmap *hintrsm, uint16_t add_flag, struct mbuf *s_mb, uint32_t s_moff, int hw_tls)
7430 {
7431 	struct tcp_rack *rack;
7432 	struct rack_sendmap *rsm, *nrsm, *insret, fe;
7433 	register uint32_t snd_max, snd_una;
7434 
7435 	/*
7436 	 * Add to the RACK log of packets in flight or retransmitted. If
7437 	 * there is a TS option we will use the TS echoed, if not we will
7438 	 * grab a TS.
7439 	 *
7440 	 * Retransmissions will increment the count and move the ts to its
7441 	 * proper place. Note that if options do not include TS's then we
7442 	 * won't be able to effectively use the ACK for an RTT on a retran.
7443 	 *
7444 	 * Notes about r_start and r_end. Lets consider a send starting at
7445 	 * sequence 1 for 10 bytes. In such an example the r_start would be
7446 	 * 1 (starting sequence) but the r_end would be r_start+len i.e. 11.
7447 	 * This means that r_end is actually the first sequence for the next
7448 	 * slot (11).
7449 	 *
7450 	 */
7451 	/*
7452 	 * If err is set what do we do XXXrrs? should we not add the thing?
7453 	 * -- i.e. return if err != 0 or should we pretend we sent it? --
7454 	 * i.e. proceed with add ** do this for now.
7455 	 */
7456 	INP_WLOCK_ASSERT(tp->t_inpcb);
7457 	if (err)
7458 		/*
7459 		 * We don't log errors -- we could but snd_max does not
7460 		 * advance in this case either.
7461 		 */
7462 		return;
7463 
7464 	if (th_flags & TH_RST) {
7465 		/*
7466 		 * We don't log resets and we return immediately from
7467 		 * sending
7468 		 */
7469 		return;
7470 	}
7471 	rack = (struct tcp_rack *)tp->t_fb_ptr;
7472 	snd_una = tp->snd_una;
7473 	snd_max = tp->snd_max;
7474 	if (th_flags & (TH_SYN | TH_FIN)) {
7475 		/*
7476 		 * The call to rack_log_output is made before bumping
7477 		 * snd_max. This means we can record one extra byte on a SYN
7478 		 * or FIN if seq_out is adding more on and a FIN is present
7479 		 * (and we are not resending).
7480 		 */
7481 		if ((th_flags & TH_SYN) && (seq_out == tp->iss))
7482 			len++;
7483 		if (th_flags & TH_FIN)
7484 			len++;
7485 		if (SEQ_LT(snd_max, tp->snd_nxt)) {
7486 			/*
7487 			 * The add/update as not been done for the FIN/SYN
7488 			 * yet.
7489 			 */
7490 			snd_max = tp->snd_nxt;
7491 		}
7492 	}
7493 	if (SEQ_LEQ((seq_out + len), snd_una)) {
7494 		/* Are sending an old segment to induce an ack (keep-alive)? */
7495 		return;
7496 	}
7497 	if (SEQ_LT(seq_out, snd_una)) {
7498 		/* huh? should we panic? */
7499 		uint32_t end;
7500 
7501 		end = seq_out + len;
7502 		seq_out = snd_una;
7503 		if (SEQ_GEQ(end, seq_out))
7504 			len = end - seq_out;
7505 		else
7506 			len = 0;
7507 	}
7508 	if (len == 0) {
7509 		/* We don't log zero window probes */
7510 		return;
7511 	}
7512 	rack->r_ctl.rc_time_last_sent = cts;
7513 	if (IN_FASTRECOVERY(tp->t_flags)) {
7514 		rack->r_ctl.rc_prr_out += len;
7515 	}
7516 	/* First question is it a retransmission or new? */
7517 	if (seq_out == snd_max) {
7518 		/* Its new */
7519 again:
7520 		rsm = rack_alloc(rack);
7521 		if (rsm == NULL) {
7522 			/*
7523 			 * Hmm out of memory and the tcb got destroyed while
7524 			 * we tried to wait.
7525 			 */
7526 			return;
7527 		}
7528 		if (th_flags & TH_FIN) {
7529 			rsm->r_flags = RACK_HAS_FIN|add_flag;
7530 		} else {
7531 			rsm->r_flags = add_flag;
7532 		}
7533 		if (hw_tls)
7534 			rsm->r_hw_tls = 1;
7535 		rsm->r_tim_lastsent[0] = cts;
7536 		rsm->r_rtr_cnt = 1;
7537 		rsm->r_rtr_bytes = 0;
7538 		if (th_flags & TH_SYN) {
7539 			/* The data space is one beyond snd_una */
7540 			rsm->r_flags |= RACK_HAS_SYN;
7541 		}
7542 		rsm->r_start = seq_out;
7543 		rsm->r_end = rsm->r_start + len;
7544 		rsm->r_dupack = 0;
7545 		/*
7546 		 * save off the mbuf location that
7547 		 * sndmbuf_noadv returned (which is
7548 		 * where we started copying from)..
7549 		 */
7550 		rsm->m = s_mb;
7551 		rsm->soff = s_moff;
7552 		/*
7553 		 * Here we do add in the len of send, since its not yet
7554 		 * reflected in in snduna <->snd_max
7555 		 */
7556 		rsm->r_fas = (ctf_flight_size(rack->rc_tp,
7557 					      rack->r_ctl.rc_sacked) +
7558 			      (rsm->r_end - rsm->r_start));
7559 		/* rsm->m will be NULL if RACK_HAS_SYN or RACK_HAS_FIN is set */
7560 		if (rsm->m) {
7561 			if (rsm->m->m_len <= rsm->soff) {
7562 				/*
7563 				 * XXXrrs Question, will this happen?
7564 				 *
7565 				 * If sbsndptr is set at the correct place
7566 				 * then s_moff should always be somewhere
7567 				 * within rsm->m. But if the sbsndptr was
7568 				 * off then that won't be true. If it occurs
7569 				 * we need to walkout to the correct location.
7570 				 */
7571 				struct mbuf *lm;
7572 
7573 				lm = rsm->m;
7574 				while (lm->m_len <= rsm->soff) {
7575 					rsm->soff -= lm->m_len;
7576 					lm = lm->m_next;
7577 					KASSERT(lm != NULL, ("%s rack:%p lm goes null orig_off:%u origmb:%p rsm->soff:%u",
7578 							     __func__, rack, s_moff, s_mb, rsm->soff));
7579 				}
7580 				rsm->m = lm;
7581 				counter_u64_add(rack_sbsndptr_wrong, 1);
7582 			} else
7583 				counter_u64_add(rack_sbsndptr_right, 1);
7584 			rsm->orig_m_len = rsm->m->m_len;
7585 		} else
7586 			rsm->orig_m_len = 0;
7587 		rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
7588 		/* Log a new rsm */
7589 		rack_log_map_chg(tp, rack, NULL, rsm, NULL, MAP_NEW, 0, __LINE__);
7590 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7591 #ifdef INVARIANTS
7592 		if (insret != NULL) {
7593 			panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
7594 			      nrsm, insret, rack, rsm);
7595 		}
7596 #endif
7597 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7598 		rsm->r_in_tmap = 1;
7599 		/*
7600 		 * Special case detection, is there just a single
7601 		 * packet outstanding when we are not in recovery?
7602 		 *
7603 		 * If this is true mark it so.
7604 		 */
7605 		if ((IN_FASTRECOVERY(tp->t_flags) == 0) &&
7606 		    (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) == ctf_fixed_maxseg(tp))) {
7607 			struct rack_sendmap *prsm;
7608 
7609 			prsm = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7610 			if (prsm)
7611 				prsm->r_one_out_nr = 1;
7612 		}
7613 		return;
7614 	}
7615 	/*
7616 	 * If we reach here its a retransmission and we need to find it.
7617 	 */
7618 	memset(&fe, 0, sizeof(fe));
7619 more:
7620 	if (hintrsm && (hintrsm->r_start == seq_out)) {
7621 		rsm = hintrsm;
7622 		hintrsm = NULL;
7623 	} else {
7624 		/* No hints sorry */
7625 		rsm = NULL;
7626 	}
7627 	if ((rsm) && (rsm->r_start == seq_out)) {
7628 		seq_out = rack_update_entry(tp, rack, rsm, cts, &len, add_flag);
7629 		if (len == 0) {
7630 			return;
7631 		} else {
7632 			goto more;
7633 		}
7634 	}
7635 	/* Ok it was not the last pointer go through it the hard way. */
7636 refind:
7637 	fe.r_start = seq_out;
7638 	rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
7639 	if (rsm) {
7640 		if (rsm->r_start == seq_out) {
7641 			seq_out = rack_update_entry(tp, rack, rsm, cts, &len, add_flag);
7642 			if (len == 0) {
7643 				return;
7644 			} else {
7645 				goto refind;
7646 			}
7647 		}
7648 		if (SEQ_GEQ(seq_out, rsm->r_start) && SEQ_LT(seq_out, rsm->r_end)) {
7649 			/* Transmitted within this piece */
7650 			/*
7651 			 * Ok we must split off the front and then let the
7652 			 * update do the rest
7653 			 */
7654 			nrsm = rack_alloc_full_limit(rack);
7655 			if (nrsm == NULL) {
7656 				rack_update_rsm(tp, rack, rsm, cts, add_flag);
7657 				return;
7658 			}
7659 			/*
7660 			 * copy rsm to nrsm and then trim the front of rsm
7661 			 * to not include this part.
7662 			 */
7663 			rack_clone_rsm(rack, nrsm, rsm, seq_out);
7664 			insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
7665 			rack_log_map_chg(tp, rack, NULL, rsm, nrsm, MAP_SPLIT, 0, __LINE__);
7666 #ifdef INVARIANTS
7667 			if (insret != NULL) {
7668 				panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
7669 				      nrsm, insret, rack, rsm);
7670 			}
7671 #endif
7672 			if (rsm->r_in_tmap) {
7673 				TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
7674 				nrsm->r_in_tmap = 1;
7675 			}
7676 			rsm->r_flags &= (~RACK_HAS_FIN);
7677 			seq_out = rack_update_entry(tp, rack, nrsm, cts, &len, add_flag);
7678 			if (len == 0) {
7679 				return;
7680 			} else if (len > 0)
7681 				goto refind;
7682 		}
7683 	}
7684 	/*
7685 	 * Hmm not found in map did they retransmit both old and on into the
7686 	 * new?
7687 	 */
7688 	if (seq_out == tp->snd_max) {
7689 		goto again;
7690 	} else if (SEQ_LT(seq_out, tp->snd_max)) {
7691 #ifdef INVARIANTS
7692 		printf("seq_out:%u len:%d snd_una:%u snd_max:%u -- but rsm not found?\n",
7693 		       seq_out, len, tp->snd_una, tp->snd_max);
7694 		printf("Starting Dump of all rack entries\n");
7695 		RB_FOREACH(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
7696 			printf("rsm:%p start:%u end:%u\n",
7697 			       rsm, rsm->r_start, rsm->r_end);
7698 		}
7699 		printf("Dump complete\n");
7700 		panic("seq_out not found rack:%p tp:%p",
7701 		      rack, tp);
7702 #endif
7703 	} else {
7704 #ifdef INVARIANTS
7705 		/*
7706 		 * Hmm beyond sndmax? (only if we are using the new rtt-pack
7707 		 * flag)
7708 		 */
7709 		panic("seq_out:%u(%d) is beyond snd_max:%u tp:%p",
7710 		      seq_out, len, tp->snd_max, tp);
7711 #endif
7712 	}
7713 }
7714 
7715 /*
7716  * Record one of the RTT updates from an ack into
7717  * our sample structure.
7718  */
7719 
7720 static void
7721 tcp_rack_xmit_timer(struct tcp_rack *rack, int32_t rtt, uint32_t len, uint32_t us_rtt,
7722 		    int confidence, struct rack_sendmap *rsm, uint16_t rtrcnt)
7723 {
7724 	if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) ||
7725 	    (rack->r_ctl.rack_rs.rs_rtt_lowest > rtt)) {
7726 		rack->r_ctl.rack_rs.rs_rtt_lowest = rtt;
7727 	}
7728 	if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) ||
7729 	    (rack->r_ctl.rack_rs.rs_rtt_highest < rtt)) {
7730 		rack->r_ctl.rack_rs.rs_rtt_highest = rtt;
7731 	}
7732 	if (rack->rc_tp->t_flags & TF_GPUTINPROG) {
7733 	    if (us_rtt < rack->r_ctl.rc_gp_lowrtt)
7734 		rack->r_ctl.rc_gp_lowrtt = us_rtt;
7735 	    if (rack->rc_tp->snd_wnd > rack->r_ctl.rc_gp_high_rwnd)
7736 		    rack->r_ctl.rc_gp_high_rwnd = rack->rc_tp->snd_wnd;
7737 	}
7738 	if ((confidence == 1) &&
7739 	    ((rsm == NULL) ||
7740 	     (rsm->r_just_ret) ||
7741 	     (rsm->r_one_out_nr &&
7742 	      len < (ctf_fixed_maxseg(rack->rc_tp) * 2)))) {
7743 		/*
7744 		 * If the rsm had a just return
7745 		 * hit it then we can't trust the
7746 		 * rtt measurement for buffer deterimination
7747 		 * Note that a confidence of 2, indicates
7748 		 * SACK'd which overrides the r_just_ret or
7749 		 * the r_one_out_nr. If it was a CUM-ACK and
7750 		 * we had only two outstanding, but get an
7751 		 * ack for only 1. Then that also lowers our
7752 		 * confidence.
7753 		 */
7754 		confidence = 0;
7755 	}
7756 	if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) ||
7757 	    (rack->r_ctl.rack_rs.rs_us_rtt > us_rtt)) {
7758 		if (rack->r_ctl.rack_rs.confidence == 0) {
7759 			/*
7760 			 * We take anything with no current confidence
7761 			 * saved.
7762 			 */
7763 			rack->r_ctl.rack_rs.rs_us_rtt = us_rtt;
7764 			rack->r_ctl.rack_rs.confidence = confidence;
7765 			rack->r_ctl.rack_rs.rs_us_rtrcnt = rtrcnt;
7766 		} else if (confidence || rack->r_ctl.rack_rs.confidence) {
7767 			/*
7768 			 * Once we have a confident number,
7769 			 * we can update it with a smaller
7770 			 * value since this confident number
7771 			 * may include the DSACK time until
7772 			 * the next segment (the second one) arrived.
7773 			 */
7774 			rack->r_ctl.rack_rs.rs_us_rtt = us_rtt;
7775 			rack->r_ctl.rack_rs.confidence = confidence;
7776 			rack->r_ctl.rack_rs.rs_us_rtrcnt = rtrcnt;
7777 		}
7778 	}
7779 	rack_log_rtt_upd(rack->rc_tp, rack, us_rtt, len, rsm, confidence);
7780 	rack->r_ctl.rack_rs.rs_flags = RACK_RTT_VALID;
7781 	rack->r_ctl.rack_rs.rs_rtt_tot += rtt;
7782 	rack->r_ctl.rack_rs.rs_rtt_cnt++;
7783 }
7784 
7785 /*
7786  * Collect new round-trip time estimate
7787  * and update averages and current timeout.
7788  */
7789 static void
7790 tcp_rack_xmit_timer_commit(struct tcp_rack *rack, struct tcpcb *tp)
7791 {
7792 	int32_t delta;
7793 	uint32_t o_srtt, o_var;
7794 	int32_t hrtt_up = 0;
7795 	int32_t rtt;
7796 
7797 	if (rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY)
7798 		/* No valid sample */
7799 		return;
7800 	if (rack->r_ctl.rc_rate_sample_method == USE_RTT_LOW) {
7801 		/* We are to use the lowest RTT seen in a single ack */
7802 		rtt = rack->r_ctl.rack_rs.rs_rtt_lowest;
7803 	} else if (rack->r_ctl.rc_rate_sample_method == USE_RTT_HIGH) {
7804 		/* We are to use the highest RTT seen in a single ack */
7805 		rtt = rack->r_ctl.rack_rs.rs_rtt_highest;
7806 	} else if (rack->r_ctl.rc_rate_sample_method == USE_RTT_AVG) {
7807 		/* We are to use the average RTT seen in a single ack */
7808 		rtt = (int32_t)(rack->r_ctl.rack_rs.rs_rtt_tot /
7809 				(uint64_t)rack->r_ctl.rack_rs.rs_rtt_cnt);
7810 	} else {
7811 #ifdef INVARIANTS
7812 		panic("Unknown rtt variant %d", rack->r_ctl.rc_rate_sample_method);
7813 #endif
7814 		return;
7815 	}
7816 	if (rtt == 0)
7817 		rtt = 1;
7818 	if (rack->rc_gp_rtt_set == 0) {
7819 		/*
7820 		 * With no RTT we have to accept
7821 		 * even one we are not confident of.
7822 		 */
7823 		rack->r_ctl.rc_gp_srtt = rack->r_ctl.rack_rs.rs_us_rtt;
7824 		rack->rc_gp_rtt_set = 1;
7825 	} else if (rack->r_ctl.rack_rs.confidence) {
7826 		/* update the running gp srtt */
7827 		rack->r_ctl.rc_gp_srtt -= (rack->r_ctl.rc_gp_srtt/8);
7828 		rack->r_ctl.rc_gp_srtt += rack->r_ctl.rack_rs.rs_us_rtt / 8;
7829 	}
7830 	if (rack->r_ctl.rack_rs.confidence) {
7831 		/*
7832 		 * record the low and high for highly buffered path computation,
7833 		 * we only do this if we are confident (not a retransmission).
7834 		 */
7835 		if (rack->r_ctl.rc_highest_us_rtt < rack->r_ctl.rack_rs.rs_us_rtt) {
7836 			rack->r_ctl.rc_highest_us_rtt = rack->r_ctl.rack_rs.rs_us_rtt;
7837 			hrtt_up = 1;
7838 		}
7839 		if (rack->rc_highly_buffered == 0) {
7840 			/*
7841 			 * Currently once we declare a path has
7842 			 * highly buffered there is no going
7843 			 * back, which may be a problem...
7844 			 */
7845 			if ((rack->r_ctl.rc_highest_us_rtt / rack->r_ctl.rc_lowest_us_rtt) > rack_hbp_thresh) {
7846 				rack_log_rtt_shrinks(rack, rack->r_ctl.rack_rs.rs_us_rtt,
7847 						     rack->r_ctl.rc_highest_us_rtt,
7848 						     rack->r_ctl.rc_lowest_us_rtt,
7849 						     RACK_RTTS_SEEHBP);
7850 				rack->rc_highly_buffered = 1;
7851 			}
7852 		}
7853 	}
7854 	if ((rack->r_ctl.rack_rs.confidence) ||
7855 	    (rack->r_ctl.rack_rs.rs_us_rtrcnt == 1)) {
7856 		/*
7857 		 * If we are highly confident of it <or> it was
7858 		 * never retransmitted we accept it as the last us_rtt.
7859 		 */
7860 		rack->r_ctl.rc_last_us_rtt = rack->r_ctl.rack_rs.rs_us_rtt;
7861 		/* The lowest rtt can be set if its was not retransmited */
7862 		if (rack->r_ctl.rc_lowest_us_rtt > rack->r_ctl.rack_rs.rs_us_rtt) {
7863 			rack->r_ctl.rc_lowest_us_rtt = rack->r_ctl.rack_rs.rs_us_rtt;
7864 			if (rack->r_ctl.rc_lowest_us_rtt == 0)
7865 				rack->r_ctl.rc_lowest_us_rtt = 1;
7866 		}
7867 	}
7868 	o_srtt = tp->t_srtt;
7869 	o_var = tp->t_rttvar;
7870 	rack = (struct tcp_rack *)tp->t_fb_ptr;
7871 	if (tp->t_srtt != 0) {
7872 		/*
7873 		 * We keep a simple srtt in microseconds, like our rtt
7874 		 * measurement. We don't need to do any tricks with shifting
7875 		 * etc. Instead we just add in 1/8th of the new measurement
7876 		 * and subtract out 1/8 of the old srtt. We do the same with
7877 		 * the variance after finding the absolute value of the
7878 		 * difference between this sample and the current srtt.
7879 		 */
7880 		delta = tp->t_srtt - rtt;
7881 		/* Take off 1/8th of the current sRTT */
7882 		tp->t_srtt -= (tp->t_srtt >> 3);
7883 		/* Add in 1/8th of the new RTT just measured */
7884 		tp->t_srtt += (rtt >> 3);
7885 		if (tp->t_srtt <= 0)
7886 			tp->t_srtt = 1;
7887 		/* Now lets make the absolute value of the variance */
7888 		if (delta < 0)
7889 			delta = -delta;
7890 		/* Subtract out 1/8th */
7891 		tp->t_rttvar -= (tp->t_rttvar >> 3);
7892 		/* Add in 1/8th of the new variance we just saw */
7893 		tp->t_rttvar += (delta >> 3);
7894 		if (tp->t_rttvar <= 0)
7895 			tp->t_rttvar = 1;
7896 		if (tp->t_rttbest > tp->t_srtt + tp->t_rttvar)
7897 			tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
7898 	} else {
7899 		/*
7900 		 * No rtt measurement yet - use the unsmoothed rtt. Set the
7901 		 * variance to half the rtt (so our first retransmit happens
7902 		 * at 3*rtt).
7903 		 */
7904 		tp->t_srtt = rtt;
7905 		tp->t_rttvar = rtt >> 1;
7906 		tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
7907 	}
7908 	rack->rc_srtt_measure_made = 1;
7909 	KMOD_TCPSTAT_INC(tcps_rttupdated);
7910 	tp->t_rttupdated++;
7911 #ifdef STATS
7912 	if (rack_stats_gets_ms_rtt == 0) {
7913 		/* Send in the microsecond rtt used for rxt timeout purposes */
7914 		stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, rtt));
7915 	} else if (rack_stats_gets_ms_rtt == 1) {
7916 		/* Send in the millisecond rtt used for rxt timeout purposes */
7917 		int32_t ms_rtt;
7918 
7919 		/* Round up */
7920 		ms_rtt = (rtt + HPTS_USEC_IN_MSEC - 1) / HPTS_USEC_IN_MSEC;
7921 		stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, ms_rtt));
7922 	} else if (rack_stats_gets_ms_rtt == 2) {
7923 		/* Send in the millisecond rtt has close to the path RTT as we can get  */
7924 		int32_t ms_rtt;
7925 
7926 		/* Round up */
7927 		ms_rtt = (rack->r_ctl.rack_rs.rs_us_rtt + HPTS_USEC_IN_MSEC - 1) / HPTS_USEC_IN_MSEC;
7928 		stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, ms_rtt));
7929 	}  else {
7930 		/* Send in the microsecond rtt has close to the path RTT as we can get  */
7931 		stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, rack->r_ctl.rack_rs.rs_us_rtt));
7932 	}
7933 
7934 #endif
7935 	/*
7936 	 * the retransmit should happen at rtt + 4 * rttvar. Because of the
7937 	 * way we do the smoothing, srtt and rttvar will each average +1/2
7938 	 * tick of bias.  When we compute the retransmit timer, we want 1/2
7939 	 * tick of rounding and 1 extra tick because of +-1/2 tick
7940 	 * uncertainty in the firing of the timer.  The bias will give us
7941 	 * exactly the 1.5 tick we need.  But, because the bias is
7942 	 * statistical, we have to test that we don't drop below the minimum
7943 	 * feasible timer (which is 2 ticks).
7944 	 */
7945 	tp->t_rxtshift = 0;
7946 	RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
7947 		      max(rack_rto_min, rtt + 2), rack_rto_max, rack->r_ctl.timer_slop);
7948 	rack_log_rtt_sample(rack, rtt);
7949 	tp->t_softerror = 0;
7950 }
7951 
7952 
7953 static void
7954 rack_apply_updated_usrtt(struct tcp_rack *rack, uint32_t us_rtt, uint32_t us_cts)
7955 {
7956 	/*
7957 	 * Apply to filter the inbound us-rtt at us_cts.
7958 	 */
7959 	uint32_t old_rtt;
7960 
7961 	old_rtt = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
7962 	apply_filter_min_small(&rack->r_ctl.rc_gp_min_rtt,
7963 			       us_rtt, us_cts);
7964 	if (rack->r_ctl.last_pacing_time &&
7965 	    rack->rc_gp_dyn_mul &&
7966 	    (rack->r_ctl.last_pacing_time > us_rtt))
7967 		rack->pacing_longer_than_rtt = 1;
7968 	else
7969 		rack->pacing_longer_than_rtt = 0;
7970 	if (old_rtt > us_rtt) {
7971 		/* We just hit a new lower rtt time */
7972 		rack_log_rtt_shrinks(rack,  us_cts,  old_rtt,
7973 				     __LINE__, RACK_RTTS_NEWRTT);
7974 		/*
7975 		 * Only count it if its lower than what we saw within our
7976 		 * calculated range.
7977 		 */
7978 		if ((old_rtt - us_rtt) > rack_min_rtt_movement) {
7979 			if (rack_probertt_lower_within &&
7980 			    rack->rc_gp_dyn_mul &&
7981 			    (rack->use_fixed_rate == 0) &&
7982 			    (rack->rc_always_pace)) {
7983 				/*
7984 				 * We are seeing a new lower rtt very close
7985 				 * to the time that we would have entered probe-rtt.
7986 				 * This is probably due to the fact that a peer flow
7987 				 * has entered probe-rtt. Lets go in now too.
7988 				 */
7989 				uint32_t val;
7990 
7991 				val = rack_probertt_lower_within * rack_time_between_probertt;
7992 				val /= 100;
7993 				if ((rack->in_probe_rtt == 0)  &&
7994 				    ((us_cts - rack->r_ctl.rc_lower_rtt_us_cts) >= (rack_time_between_probertt - val)))	{
7995 					rack_enter_probertt(rack, us_cts);
7996 				}
7997 			}
7998 			rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
7999 		}
8000 	}
8001 }
8002 
8003 static int
8004 rack_update_rtt(struct tcpcb *tp, struct tcp_rack *rack,
8005     struct rack_sendmap *rsm, struct tcpopt *to, uint32_t cts, int32_t ack_type, tcp_seq th_ack)
8006 {
8007 	uint32_t us_rtt;
8008 	int32_t i, all;
8009 	uint32_t t, len_acked;
8010 
8011 	if ((rsm->r_flags & RACK_ACKED) ||
8012 	    (rsm->r_flags & RACK_WAS_ACKED))
8013 		/* Already done */
8014 		return (0);
8015 	if (rsm->r_no_rtt_allowed) {
8016 		/* Not allowed */
8017 		return (0);
8018 	}
8019 	if (ack_type == CUM_ACKED) {
8020 		if (SEQ_GT(th_ack, rsm->r_end)) {
8021 			len_acked = rsm->r_end - rsm->r_start;
8022 			all = 1;
8023 		} else {
8024 			len_acked = th_ack - rsm->r_start;
8025 			all = 0;
8026 		}
8027 	} else {
8028 		len_acked = rsm->r_end - rsm->r_start;
8029 		all = 0;
8030 	}
8031 	if (rsm->r_rtr_cnt == 1) {
8032 
8033 		t = cts - (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
8034 		if ((int)t <= 0)
8035 			t = 1;
8036 		if (!tp->t_rttlow || tp->t_rttlow > t)
8037 			tp->t_rttlow = t;
8038 		if (!rack->r_ctl.rc_rack_min_rtt ||
8039 		    SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
8040 			rack->r_ctl.rc_rack_min_rtt = t;
8041 			if (rack->r_ctl.rc_rack_min_rtt == 0) {
8042 				rack->r_ctl.rc_rack_min_rtt = 1;
8043 			}
8044 		}
8045 		if (TSTMP_GT(tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time), rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)]))
8046 			us_rtt = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time) - (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
8047 		else
8048 			us_rtt = tcp_get_usecs(NULL) - (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
8049 		if (us_rtt == 0)
8050 			us_rtt = 1;
8051 		if (CC_ALGO(tp)->rttsample != NULL) {
8052 			/* Kick the RTT to the CC */
8053 			CC_ALGO(tp)->rttsample(tp->ccv, us_rtt, 1, rsm->r_fas);
8054 		}
8055 		rack_apply_updated_usrtt(rack, us_rtt, tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time));
8056 		if (ack_type == SACKED) {
8057 			rack_log_rtt_sample_calc(rack, t, (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)], cts, 1);
8058 			tcp_rack_xmit_timer(rack, t + 1, len_acked, us_rtt, 2 , rsm, rsm->r_rtr_cnt);
8059 		} else {
8060 			/*
8061 			 * We need to setup what our confidence
8062 			 * is in this ack.
8063 			 *
8064 			 * If the rsm was app limited and it is
8065 			 * less than a mss in length (the end
8066 			 * of the send) then we have a gap. If we
8067 			 * were app limited but say we were sending
8068 			 * multiple MSS's then we are more confident
8069 			 * int it.
8070 			 *
8071 			 * When we are not app-limited then we see if
8072 			 * the rsm is being included in the current
8073 			 * measurement, we tell this by the app_limited_needs_set
8074 			 * flag.
8075 			 *
8076 			 * Note that being cwnd blocked is not applimited
8077 			 * as well as the pacing delay between packets which
8078 			 * are sending only 1 or 2 MSS's also will show up
8079 			 * in the RTT. We probably need to examine this algorithm
8080 			 * a bit more and enhance it to account for the delay
8081 			 * between rsm's. We could do that by saving off the
8082 			 * pacing delay of each rsm (in an rsm) and then
8083 			 * factoring that in somehow though for now I am
8084 			 * not sure how :)
8085 			 */
8086 			int calc_conf = 0;
8087 
8088 			if (rsm->r_flags & RACK_APP_LIMITED) {
8089 				if (all && (len_acked <= ctf_fixed_maxseg(tp)))
8090 					calc_conf = 0;
8091 				else
8092 					calc_conf = 1;
8093 			} else if (rack->app_limited_needs_set == 0) {
8094 				calc_conf = 1;
8095 			} else {
8096 				calc_conf = 0;
8097 			}
8098 			rack_log_rtt_sample_calc(rack, t, (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)], cts, 2);
8099 			tcp_rack_xmit_timer(rack, t + 1, len_acked, us_rtt,
8100 					    calc_conf, rsm, rsm->r_rtr_cnt);
8101 		}
8102 		if ((rsm->r_flags & RACK_TLP) &&
8103 		    (!IN_FASTRECOVERY(tp->t_flags))) {
8104 			/* Segment was a TLP and our retrans matched */
8105 			if (rack->r_ctl.rc_tlp_cwnd_reduce) {
8106 				rack->r_ctl.rc_rsm_start = tp->snd_max;
8107 				rack->r_ctl.rc_cwnd_at = tp->snd_cwnd;
8108 				rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh;
8109 				rack_cong_signal(tp, CC_NDUPACK, tp->snd_una);
8110 			}
8111 		}
8112 		if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time, (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)])) {
8113 			/* New more recent rack_tmit_time */
8114 			rack->r_ctl.rc_rack_tmit_time = (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
8115 			rack->rc_rack_rtt = t;
8116 		}
8117 		return (1);
8118 	}
8119 	/*
8120 	 * We clear the soft/rxtshift since we got an ack.
8121 	 * There is no assurance we will call the commit() function
8122 	 * so we need to clear these to avoid incorrect handling.
8123 	 */
8124 	tp->t_rxtshift = 0;
8125 	RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
8126 		      rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
8127 	tp->t_softerror = 0;
8128 	if (to && (to->to_flags & TOF_TS) &&
8129 	    (ack_type == CUM_ACKED) &&
8130 	    (to->to_tsecr) &&
8131 	    ((rsm->r_flags & RACK_OVERMAX) == 0)) {
8132 		/*
8133 		 * Now which timestamp does it match? In this block the ACK
8134 		 * must be coming from a previous transmission.
8135 		 */
8136 		for (i = 0; i < rsm->r_rtr_cnt; i++) {
8137 			if (rack_ts_to_msec(rsm->r_tim_lastsent[i]) == to->to_tsecr) {
8138 				t = cts - (uint32_t)rsm->r_tim_lastsent[i];
8139 				if ((int)t <= 0)
8140 					t = 1;
8141 				if (CC_ALGO(tp)->rttsample != NULL) {
8142 					/*
8143 					 * Kick the RTT to the CC, here
8144 					 * we lie a bit in that we know the
8145 					 * retransmission is correct even though
8146 					 * we retransmitted. This is because
8147 					 * we match the timestamps.
8148 					 */
8149 					if (TSTMP_GT(tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time), rsm->r_tim_lastsent[i]))
8150 						us_rtt = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time) - (uint32_t)rsm->r_tim_lastsent[i];
8151 					else
8152 						us_rtt = tcp_get_usecs(NULL) - (uint32_t)rsm->r_tim_lastsent[i];
8153 					CC_ALGO(tp)->rttsample(tp->ccv, us_rtt, 1, rsm->r_fas);
8154 				}
8155 				if ((i + 1) < rsm->r_rtr_cnt) {
8156 					/*
8157 					 * The peer ack'd from our previous
8158 					 * transmission. We have a spurious
8159 					 * retransmission and thus we dont
8160 					 * want to update our rack_rtt.
8161 					 *
8162 					 * Hmm should there be a CC revert here?
8163 					 *
8164 					 */
8165 					return (0);
8166 				}
8167 				if (!tp->t_rttlow || tp->t_rttlow > t)
8168 					tp->t_rttlow = t;
8169 				if (!rack->r_ctl.rc_rack_min_rtt || SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
8170 					rack->r_ctl.rc_rack_min_rtt = t;
8171 					if (rack->r_ctl.rc_rack_min_rtt == 0) {
8172 						rack->r_ctl.rc_rack_min_rtt = 1;
8173 					}
8174 				}
8175 				if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time,
8176 					   (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)])) {
8177 					/* New more recent rack_tmit_time */
8178 					rack->r_ctl.rc_rack_tmit_time = (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
8179 					rack->rc_rack_rtt = t;
8180 				}
8181 				rack_log_rtt_sample_calc(rack, t, (uint32_t)rsm->r_tim_lastsent[i], cts, 3);
8182 				tcp_rack_xmit_timer(rack, t + 1, len_acked, t, 0, rsm,
8183 						    rsm->r_rtr_cnt);
8184 				return (1);
8185 			}
8186 		}
8187 		goto ts_not_found;
8188 	} else {
8189 		/*
8190 		 * Ok its a SACK block that we retransmitted. or a windows
8191 		 * machine without timestamps. We can tell nothing from the
8192 		 * time-stamp since its not there or the time the peer last
8193 		 * recieved a segment that moved forward its cum-ack point.
8194 		 */
8195 ts_not_found:
8196 		i = rsm->r_rtr_cnt - 1;
8197 		t = cts - (uint32_t)rsm->r_tim_lastsent[i];
8198 		if ((int)t <= 0)
8199 			t = 1;
8200 		if (rack->r_ctl.rc_rack_min_rtt && SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
8201 			/*
8202 			 * We retransmitted and the ack came back in less
8203 			 * than the smallest rtt we have observed. We most
8204 			 * likely did an improper retransmit as outlined in
8205 			 * 6.2 Step 2 point 2 in the rack-draft so we
8206 			 * don't want to update our rack_rtt. We in
8207 			 * theory (in future) might want to think about reverting our
8208 			 * cwnd state but we won't for now.
8209 			 */
8210 			return (0);
8211 		} else if (rack->r_ctl.rc_rack_min_rtt) {
8212 			/*
8213 			 * We retransmitted it and the retransmit did the
8214 			 * job.
8215 			 */
8216 			if (!rack->r_ctl.rc_rack_min_rtt ||
8217 			    SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
8218 				rack->r_ctl.rc_rack_min_rtt = t;
8219 				if (rack->r_ctl.rc_rack_min_rtt == 0) {
8220 					rack->r_ctl.rc_rack_min_rtt = 1;
8221 				}
8222 			}
8223 			if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time, (uint32_t)rsm->r_tim_lastsent[i])) {
8224 				/* New more recent rack_tmit_time */
8225 				rack->r_ctl.rc_rack_tmit_time = (uint32_t)rsm->r_tim_lastsent[i];
8226 				rack->rc_rack_rtt = t;
8227 			}
8228 			return (1);
8229 		}
8230 	}
8231 	return (0);
8232 }
8233 
8234 /*
8235  * Mark the SACK_PASSED flag on all entries prior to rsm send wise.
8236  */
8237 static void
8238 rack_log_sack_passed(struct tcpcb *tp,
8239     struct tcp_rack *rack, struct rack_sendmap *rsm)
8240 {
8241 	struct rack_sendmap *nrsm;
8242 
8243 	nrsm = rsm;
8244 	TAILQ_FOREACH_REVERSE_FROM(nrsm, &rack->r_ctl.rc_tmap,
8245 	    rack_head, r_tnext) {
8246 		if (nrsm == rsm) {
8247 			/* Skip orginal segment he is acked */
8248 			continue;
8249 		}
8250 		if (nrsm->r_flags & RACK_ACKED) {
8251 			/*
8252 			 * Skip ack'd segments, though we
8253 			 * should not see these, since tmap
8254 			 * should not have ack'd segments.
8255 			 */
8256 			continue;
8257 		}
8258 		if (nrsm->r_flags & RACK_SACK_PASSED) {
8259 			/*
8260 			 * We found one that is already marked
8261 			 * passed, we have been here before and
8262 			 * so all others below this are marked.
8263 			 */
8264 			break;
8265 		}
8266 		nrsm->r_flags |= RACK_SACK_PASSED;
8267 		nrsm->r_flags &= ~RACK_WAS_SACKPASS;
8268 	}
8269 }
8270 
8271 static void
8272 rack_need_set_test(struct tcpcb *tp,
8273 		   struct tcp_rack *rack,
8274 		   struct rack_sendmap *rsm,
8275 		   tcp_seq th_ack,
8276 		   int line,
8277 		   int use_which)
8278 {
8279 
8280 	if ((tp->t_flags & TF_GPUTINPROG) &&
8281 	    SEQ_GEQ(rsm->r_end, tp->gput_seq)) {
8282 		/*
8283 		 * We were app limited, and this ack
8284 		 * butts up or goes beyond the point where we want
8285 		 * to start our next measurement. We need
8286 		 * to record the new gput_ts as here and
8287 		 * possibly update the start sequence.
8288 		 */
8289 		uint32_t seq, ts;
8290 
8291 		if (rsm->r_rtr_cnt > 1) {
8292 			/*
8293 			 * This is a retransmit, can we
8294 			 * really make any assessment at this
8295 			 * point?  We are not really sure of
8296 			 * the timestamp, is it this or the
8297 			 * previous transmission?
8298 			 *
8299 			 * Lets wait for something better that
8300 			 * is not retransmitted.
8301 			 */
8302 			return;
8303 		}
8304 		seq = tp->gput_seq;
8305 		ts = tp->gput_ts;
8306 		rack->app_limited_needs_set = 0;
8307 		tp->gput_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
8308 		/* Do we start at a new end? */
8309 		if ((use_which == RACK_USE_BEG) &&
8310 		    SEQ_GEQ(rsm->r_start, tp->gput_seq)) {
8311 			/*
8312 			 * When we get an ACK that just eats
8313 			 * up some of the rsm, we set RACK_USE_BEG
8314 			 * since whats at r_start (i.e. th_ack)
8315 			 * is left unacked and thats where the
8316 			 * measurement not starts.
8317 			 */
8318 			tp->gput_seq = rsm->r_start;
8319 			rack->r_ctl.rc_gp_output_ts = rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
8320 		}
8321 		if ((use_which == RACK_USE_END) &&
8322 		    SEQ_GEQ(rsm->r_end, tp->gput_seq)) {
8323 			    /*
8324 			     * We use the end when the cumack
8325 			     * is moving forward and completely
8326 			     * deleting the rsm passed so basically
8327 			     * r_end holds th_ack.
8328 			     *
8329 			     * For SACK's we also want to use the end
8330 			     * since this piece just got sacked and
8331 			     * we want to target anything after that
8332 			     * in our measurement.
8333 			     */
8334 			    tp->gput_seq = rsm->r_end;
8335 			    rack->r_ctl.rc_gp_output_ts = rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
8336 		}
8337 		if (use_which == RACK_USE_END_OR_THACK) {
8338 			/*
8339 			 * special case for ack moving forward,
8340 			 * not a sack, we need to move all the
8341 			 * way up to where this ack cum-ack moves
8342 			 * to.
8343 			 */
8344 			if (SEQ_GT(th_ack, rsm->r_end))
8345 				tp->gput_seq = th_ack;
8346 			else
8347 				tp->gput_seq = rsm->r_end;
8348 			rack->r_ctl.rc_gp_output_ts = rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
8349 		}
8350 		if (SEQ_GT(tp->gput_seq, tp->gput_ack)) {
8351 			/*
8352 			 * We moved beyond this guy's range, re-calculate
8353 			 * the new end point.
8354 			 */
8355 			if (rack->rc_gp_filled == 0) {
8356 				tp->gput_ack = tp->gput_seq + max(rc_init_window(rack), (MIN_GP_WIN * ctf_fixed_maxseg(tp)));
8357 			} else {
8358 				tp->gput_ack = tp->gput_seq + rack_get_measure_window(tp, rack);
8359 			}
8360 		}
8361 		/*
8362 		 * We are moving the goal post, we may be able to clear the
8363 		 * measure_saw_probe_rtt flag.
8364 		 */
8365 		if ((rack->in_probe_rtt == 0) &&
8366 		    (rack->measure_saw_probe_rtt) &&
8367 		    (SEQ_GEQ(tp->gput_seq, rack->r_ctl.rc_probertt_sndmax_atexit)))
8368 			rack->measure_saw_probe_rtt = 0;
8369 		rack_log_pacing_delay_calc(rack, ts, tp->gput_ts,
8370 					   seq, tp->gput_seq, 0, 5, line, NULL, 0);
8371 		if (rack->rc_gp_filled &&
8372 		    ((tp->gput_ack - tp->gput_seq) <
8373 		     max(rc_init_window(rack), (MIN_GP_WIN *
8374 						ctf_fixed_maxseg(tp))))) {
8375 			uint32_t ideal_amount;
8376 
8377 			ideal_amount = rack_get_measure_window(tp, rack);
8378 			if (ideal_amount > sbavail(&tp->t_inpcb->inp_socket->so_snd)) {
8379 				/*
8380 				 * There is no sense of continuing this measurement
8381 				 * because its too small to gain us anything we
8382 				 * trust. Skip it and that way we can start a new
8383 				 * measurement quicker.
8384 				 */
8385 				tp->t_flags &= ~TF_GPUTINPROG;
8386 				rack_log_pacing_delay_calc(rack, tp->gput_ack, tp->gput_seq,
8387 							   0, 0, 0, 6, __LINE__, NULL, 0);
8388 			} else {
8389 				/*
8390 				 * Reset the window further out.
8391 				 */
8392 				tp->gput_ack = tp->gput_seq + ideal_amount;
8393 			}
8394 		}
8395 	}
8396 }
8397 
8398 static inline int
8399 is_rsm_inside_declared_tlp_block(struct tcp_rack *rack, struct rack_sendmap *rsm)
8400 {
8401 	if (SEQ_LT(rsm->r_end, rack->r_ctl.last_tlp_acked_start)) {
8402 		/* Behind our TLP definition or right at */
8403 		return (0);
8404 	}
8405 	if (SEQ_GT(rsm->r_start, rack->r_ctl.last_tlp_acked_end)) {
8406 		/* The start is beyond or right at our end of TLP definition */
8407 		return (0);
8408 	}
8409 	/* It has to be a sub-part of the original TLP recorded */
8410 	return (1);
8411 }
8412 
8413 
8414 static uint32_t
8415 rack_proc_sack_blk(struct tcpcb *tp, struct tcp_rack *rack, struct sackblk *sack,
8416 		   struct tcpopt *to, struct rack_sendmap **prsm, uint32_t cts, int *moved_two)
8417 {
8418 	uint32_t start, end, changed = 0;
8419 	struct rack_sendmap stack_map;
8420 	struct rack_sendmap *rsm, *nrsm, fe, *insret, *prev, *next;
8421 	int32_t used_ref = 1;
8422 	int moved = 0;
8423 
8424 	start = sack->start;
8425 	end = sack->end;
8426 	rsm = *prsm;
8427 	memset(&fe, 0, sizeof(fe));
8428 do_rest_ofb:
8429 	if ((rsm == NULL) ||
8430 	    (SEQ_LT(end, rsm->r_start)) ||
8431 	    (SEQ_GEQ(start, rsm->r_end)) ||
8432 	    (SEQ_LT(start, rsm->r_start))) {
8433 		/*
8434 		 * We are not in the right spot,
8435 		 * find the correct spot in the tree.
8436 		 */
8437 		used_ref = 0;
8438 		fe.r_start = start;
8439 		rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
8440 		moved++;
8441 	}
8442 	if (rsm == NULL) {
8443 		/* TSNH */
8444 		goto out;
8445 	}
8446 	/* Ok we have an ACK for some piece of this rsm */
8447 	if (rsm->r_start != start) {
8448 		if ((rsm->r_flags & RACK_ACKED) == 0) {
8449 			/*
8450 			 * Before any splitting or hookery is
8451 			 * done is it a TLP of interest i.e. rxt?
8452 			 */
8453 			if ((rsm->r_flags & RACK_TLP) &&
8454 			    (rsm->r_rtr_cnt > 1)) {
8455 				/*
8456 				 * We are splitting a rxt TLP, check
8457 				 * if we need to save off the start/end
8458 				 */
8459 				if (rack->rc_last_tlp_acked_set &&
8460 				    (is_rsm_inside_declared_tlp_block(rack, rsm))) {
8461 					/*
8462 					 * We already turned this on since we are inside
8463 					 * the previous one was a partially sack now we
8464 					 * are getting another one (maybe all of it).
8465 					 *
8466 					 */
8467 					rack_log_dsack_event(rack, 10, __LINE__, rsm->r_start, rsm->r_end);
8468 					/*
8469 					 * Lets make sure we have all of it though.
8470 					 */
8471 					if (SEQ_LT(rsm->r_start, rack->r_ctl.last_tlp_acked_start)) {
8472 						rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8473 						rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8474 								     rack->r_ctl.last_tlp_acked_end);
8475 					}
8476 					if (SEQ_GT(rsm->r_end, rack->r_ctl.last_tlp_acked_end)) {
8477 						rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8478 						rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8479 								     rack->r_ctl.last_tlp_acked_end);
8480 					}
8481 				} else {
8482 					rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8483 					rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8484 					rack->rc_last_tlp_past_cumack = 0;
8485 					rack->rc_last_tlp_acked_set = 1;
8486 					rack_log_dsack_event(rack, 8, __LINE__, rsm->r_start, rsm->r_end);
8487 				}
8488 			}
8489 			/**
8490 			 * Need to split this in two pieces the before and after,
8491 			 * the before remains in the map, the after must be
8492 			 * added. In other words we have:
8493 			 * rsm        |--------------|
8494 			 * sackblk        |------->
8495 			 * rsm will become
8496 			 *     rsm    |---|
8497 			 * and nrsm will be  the sacked piece
8498 			 *     nrsm       |----------|
8499 			 *
8500 			 * But before we start down that path lets
8501 			 * see if the sack spans over on top of
8502 			 * the next guy and it is already sacked.
8503 			 *
8504 			 */
8505 			next = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8506 			if (next && (next->r_flags & RACK_ACKED) &&
8507 			    SEQ_GEQ(end, next->r_start)) {
8508 				/**
8509 				 * So the next one is already acked, and
8510 				 * we can thus by hookery use our stack_map
8511 				 * to reflect the piece being sacked and
8512 				 * then adjust the two tree entries moving
8513 				 * the start and ends around. So we start like:
8514 				 *  rsm     |------------|             (not-acked)
8515 				 *  next                 |-----------| (acked)
8516 				 *  sackblk        |-------->
8517 				 *  We want to end like so:
8518 				 *  rsm     |------|                   (not-acked)
8519 				 *  next           |-----------------| (acked)
8520 				 *  nrsm           |-----|
8521 				 * Where nrsm is a temporary stack piece we
8522 				 * use to update all the gizmos.
8523 				 */
8524 				/* Copy up our fudge block */
8525 				nrsm = &stack_map;
8526 				memcpy(nrsm, rsm, sizeof(struct rack_sendmap));
8527 				/* Now adjust our tree blocks */
8528 				rsm->r_end = start;
8529 				next->r_start = start;
8530 				/* Now we must adjust back where next->m is */
8531 				rack_setup_offset_for_rsm(rsm, next);
8532 
8533 				/* We don't need to adjust rsm, it did not change */
8534 				/* Clear out the dup ack count of the remainder */
8535 				rsm->r_dupack = 0;
8536 				rsm->r_just_ret = 0;
8537 				rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
8538 				/* Now lets make sure our fudge block is right */
8539 				nrsm->r_start = start;
8540 				/* Now lets update all the stats and such */
8541 				rack_update_rtt(tp, rack, nrsm, to, cts, SACKED, 0);
8542 				if (rack->app_limited_needs_set)
8543 					rack_need_set_test(tp, rack, nrsm, tp->snd_una, __LINE__, RACK_USE_END);
8544 				changed += (nrsm->r_end - nrsm->r_start);
8545 				rack->r_ctl.rc_sacked += (nrsm->r_end - nrsm->r_start);
8546 				if (nrsm->r_flags & RACK_SACK_PASSED) {
8547 					counter_u64_add(rack_reorder_seen, 1);
8548 					rack->r_ctl.rc_reorder_ts = cts;
8549 				}
8550 				/*
8551 				 * Now we want to go up from rsm (the
8552 				 * one left un-acked) to the next one
8553 				 * in the tmap. We do this so when
8554 				 * we walk backwards we include marking
8555 				 * sack-passed on rsm (The one passed in
8556 				 * is skipped since it is generally called
8557 				 * on something sacked before removing it
8558 				 * from the tmap).
8559 				 */
8560 				if (rsm->r_in_tmap) {
8561 					nrsm = TAILQ_NEXT(rsm, r_tnext);
8562 					/*
8563 					 * Now that we have the next
8564 					 * one walk backwards from there.
8565 					 */
8566 					if (nrsm && nrsm->r_in_tmap)
8567 						rack_log_sack_passed(tp, rack, nrsm);
8568 				}
8569 				/* Now are we done? */
8570 				if (SEQ_LT(end, next->r_end) ||
8571 				    (end == next->r_end)) {
8572 					/* Done with block */
8573 					goto out;
8574 				}
8575 				rack_log_map_chg(tp, rack, &stack_map, rsm, next, MAP_SACK_M1, end, __LINE__);
8576 				counter_u64_add(rack_sack_used_next_merge, 1);
8577 				/* Postion for the next block */
8578 				start = next->r_end;
8579 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, next);
8580 				if (rsm == NULL)
8581 					goto out;
8582 			} else {
8583 				/**
8584 				 * We can't use any hookery here, so we
8585 				 * need to split the map. We enter like
8586 				 * so:
8587 				 *  rsm      |--------|
8588 				 *  sackblk       |----->
8589 				 * We will add the new block nrsm and
8590 				 * that will be the new portion, and then
8591 				 * fall through after reseting rsm. So we
8592 				 * split and look like this:
8593 				 *  rsm      |----|
8594 				 *  sackblk       |----->
8595 				 *  nrsm          |---|
8596 				 * We then fall through reseting
8597 				 * rsm to nrsm, so the next block
8598 				 * picks it up.
8599 				 */
8600 				nrsm = rack_alloc_limit(rack, RACK_LIMIT_TYPE_SPLIT);
8601 				if (nrsm == NULL) {
8602 					/*
8603 					 * failed XXXrrs what can we do but loose the sack
8604 					 * info?
8605 					 */
8606 					goto out;
8607 				}
8608 				counter_u64_add(rack_sack_splits, 1);
8609 				rack_clone_rsm(rack, nrsm, rsm, start);
8610 				rsm->r_just_ret = 0;
8611 				insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
8612 #ifdef INVARIANTS
8613 				if (insret != NULL) {
8614 					panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
8615 					      nrsm, insret, rack, rsm);
8616 				}
8617 #endif
8618 				if (rsm->r_in_tmap) {
8619 					TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
8620 					nrsm->r_in_tmap = 1;
8621 				}
8622 				rack_log_map_chg(tp, rack, NULL, rsm, nrsm, MAP_SACK_M2, end, __LINE__);
8623 				rsm->r_flags &= (~RACK_HAS_FIN);
8624 				/* Position us to point to the new nrsm that starts the sack blk */
8625 				rsm = nrsm;
8626 			}
8627 		} else {
8628 			/* Already sacked this piece */
8629 			counter_u64_add(rack_sack_skipped_acked, 1);
8630 			moved++;
8631 			if (end == rsm->r_end) {
8632 				/* Done with block */
8633 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8634 				goto out;
8635 			} else if (SEQ_LT(end, rsm->r_end)) {
8636 				/* A partial sack to a already sacked block */
8637 				moved++;
8638 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8639 				goto out;
8640 			} else {
8641 				/*
8642 				 * The end goes beyond this guy
8643 				 * repostion the start to the
8644 				 * next block.
8645 				 */
8646 				start = rsm->r_end;
8647 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8648 				if (rsm == NULL)
8649 					goto out;
8650 			}
8651 		}
8652 	}
8653 	if (SEQ_GEQ(end, rsm->r_end)) {
8654 		/**
8655 		 * The end of this block is either beyond this guy or right
8656 		 * at this guy. I.e.:
8657 		 *  rsm ---                 |-----|
8658 		 *  end                     |-----|
8659 		 *  <or>
8660 		 *  end                     |---------|
8661 		 */
8662 		if ((rsm->r_flags & RACK_ACKED) == 0) {
8663 			/*
8664 			 * Is it a TLP of interest?
8665 			 */
8666 			if ((rsm->r_flags & RACK_TLP) &&
8667 			    (rsm->r_rtr_cnt > 1)) {
8668 				/*
8669 				 * We are splitting a rxt TLP, check
8670 				 * if we need to save off the start/end
8671 				 */
8672 				if (rack->rc_last_tlp_acked_set &&
8673 				    (is_rsm_inside_declared_tlp_block(rack, rsm))) {
8674 					/*
8675 					 * We already turned this on since we are inside
8676 					 * the previous one was a partially sack now we
8677 					 * are getting another one (maybe all of it).
8678 					 */
8679 					rack_log_dsack_event(rack, 10, __LINE__, rsm->r_start, rsm->r_end);
8680 					/*
8681 					 * Lets make sure we have all of it though.
8682 					 */
8683 					if (SEQ_LT(rsm->r_start, rack->r_ctl.last_tlp_acked_start)) {
8684 						rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8685 						rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8686 								     rack->r_ctl.last_tlp_acked_end);
8687 					}
8688 					if (SEQ_GT(rsm->r_end, rack->r_ctl.last_tlp_acked_end)) {
8689 						rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8690 						rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8691 								     rack->r_ctl.last_tlp_acked_end);
8692 					}
8693 				} else {
8694 					rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8695 					rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8696 					rack->rc_last_tlp_past_cumack = 0;
8697 					rack->rc_last_tlp_acked_set = 1;
8698 					rack_log_dsack_event(rack, 8, __LINE__, rsm->r_start, rsm->r_end);
8699 				}
8700 			}
8701 			rack_update_rtt(tp, rack, rsm, to, cts, SACKED, 0);
8702 			changed += (rsm->r_end - rsm->r_start);
8703 			rack->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start);
8704 			if (rsm->r_in_tmap) /* should be true */
8705 				rack_log_sack_passed(tp, rack, rsm);
8706 			/* Is Reordering occuring? */
8707 			if (rsm->r_flags & RACK_SACK_PASSED) {
8708 				rsm->r_flags &= ~RACK_SACK_PASSED;
8709 				counter_u64_add(rack_reorder_seen, 1);
8710 				rack->r_ctl.rc_reorder_ts = cts;
8711 			}
8712 			if (rack->app_limited_needs_set)
8713 				rack_need_set_test(tp, rack, rsm, tp->snd_una, __LINE__, RACK_USE_END);
8714 			rsm->r_ack_arrival = rack_to_usec_ts(&rack->r_ctl.act_rcv_time);
8715 			rsm->r_flags |= RACK_ACKED;
8716 			if (rsm->r_in_tmap) {
8717 				TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
8718 				rsm->r_in_tmap = 0;
8719 			}
8720 			rack_log_map_chg(tp, rack, NULL, rsm, NULL, MAP_SACK_M3, end, __LINE__);
8721 		} else {
8722 			counter_u64_add(rack_sack_skipped_acked, 1);
8723 			moved++;
8724 		}
8725 		if (end == rsm->r_end) {
8726 			/* This block only - done, setup for next */
8727 			goto out;
8728 		}
8729 		/*
8730 		 * There is more not coverend by this rsm move on
8731 		 * to the next block in the RB tree.
8732 		 */
8733 		nrsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8734 		start = rsm->r_end;
8735 		rsm = nrsm;
8736 		if (rsm == NULL)
8737 			goto out;
8738 		goto do_rest_ofb;
8739 	}
8740 	/**
8741 	 * The end of this sack block is smaller than
8742 	 * our rsm i.e.:
8743 	 *  rsm ---                 |-----|
8744 	 *  end                     |--|
8745 	 */
8746 	if ((rsm->r_flags & RACK_ACKED) == 0) {
8747 		/*
8748 		 * Is it a TLP of interest?
8749 		 */
8750 		if ((rsm->r_flags & RACK_TLP) &&
8751 		    (rsm->r_rtr_cnt > 1)) {
8752 			/*
8753 			 * We are splitting a rxt TLP, check
8754 			 * if we need to save off the start/end
8755 			 */
8756 			if (rack->rc_last_tlp_acked_set &&
8757 			    (is_rsm_inside_declared_tlp_block(rack, rsm))) {
8758 				/*
8759 				 * We already turned this on since we are inside
8760 				 * the previous one was a partially sack now we
8761 				 * are getting another one (maybe all of it).
8762 				 */
8763 				rack_log_dsack_event(rack, 10, __LINE__, rsm->r_start, rsm->r_end);
8764 				/*
8765 				 * Lets make sure we have all of it though.
8766 				 */
8767 				if (SEQ_LT(rsm->r_start, rack->r_ctl.last_tlp_acked_start)) {
8768 					rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8769 					rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8770 							     rack->r_ctl.last_tlp_acked_end);
8771 				}
8772 				if (SEQ_GT(rsm->r_end, rack->r_ctl.last_tlp_acked_end)) {
8773 					rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8774 					rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8775 							     rack->r_ctl.last_tlp_acked_end);
8776 				}
8777 			} else {
8778 				rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8779 				rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8780 				rack->rc_last_tlp_past_cumack = 0;
8781 				rack->rc_last_tlp_acked_set = 1;
8782 				rack_log_dsack_event(rack, 8, __LINE__, rsm->r_start, rsm->r_end);
8783 			}
8784 		}
8785 		prev = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8786 		if (prev &&
8787 		    (prev->r_flags & RACK_ACKED)) {
8788 			/**
8789 			 * Goal, we want the right remainder of rsm to shrink
8790 			 * in place and span from (rsm->r_start = end) to rsm->r_end.
8791 			 * We want to expand prev to go all the way
8792 			 * to prev->r_end <- end.
8793 			 * so in the tree we have before:
8794 			 *   prev     |--------|         (acked)
8795 			 *   rsm               |-------| (non-acked)
8796 			 *   sackblk           |-|
8797 			 * We churn it so we end up with
8798 			 *   prev     |----------|       (acked)
8799 			 *   rsm                 |-----| (non-acked)
8800 			 *   nrsm              |-| (temporary)
8801 			 *
8802 			 * Note if either prev/rsm is a TLP we don't
8803 			 * do this.
8804 			 */
8805 			nrsm = &stack_map;
8806 			memcpy(nrsm, rsm, sizeof(struct rack_sendmap));
8807 			prev->r_end = end;
8808 			rsm->r_start = end;
8809 			/* Now adjust nrsm (stack copy) to be
8810 			 * the one that is the small
8811 			 * piece that was "sacked".
8812 			 */
8813 			nrsm->r_end = end;
8814 			rsm->r_dupack = 0;
8815 			rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
8816 			/*
8817 			 * Now that the rsm has had its start moved forward
8818 			 * lets go ahead and get its new place in the world.
8819 			 */
8820 			rack_setup_offset_for_rsm(prev, rsm);
8821 			/*
8822 			 * Now nrsm is our new little piece
8823 			 * that is acked (which was merged
8824 			 * to prev). Update the rtt and changed
8825 			 * based on that. Also check for reordering.
8826 			 */
8827 			rack_update_rtt(tp, rack, nrsm, to, cts, SACKED, 0);
8828 			if (rack->app_limited_needs_set)
8829 				rack_need_set_test(tp, rack, nrsm, tp->snd_una, __LINE__, RACK_USE_END);
8830 			changed += (nrsm->r_end - nrsm->r_start);
8831 			rack->r_ctl.rc_sacked += (nrsm->r_end - nrsm->r_start);
8832 			if (nrsm->r_flags & RACK_SACK_PASSED) {
8833 				counter_u64_add(rack_reorder_seen, 1);
8834 				rack->r_ctl.rc_reorder_ts = cts;
8835 			}
8836 			rack_log_map_chg(tp, rack, prev, &stack_map, rsm, MAP_SACK_M4, end, __LINE__);
8837 			rsm = prev;
8838 			counter_u64_add(rack_sack_used_prev_merge, 1);
8839 		} else {
8840 			/**
8841 			 * This is the case where our previous
8842 			 * block is not acked either, so we must
8843 			 * split the block in two.
8844 			 */
8845 			nrsm = rack_alloc_limit(rack, RACK_LIMIT_TYPE_SPLIT);
8846 			if (nrsm == NULL) {
8847 				/* failed rrs what can we do but loose the sack info? */
8848 				goto out;
8849 			}
8850 			if ((rsm->r_flags & RACK_TLP) &&
8851 			    (rsm->r_rtr_cnt > 1)) {
8852 				/*
8853 				 * We are splitting a rxt TLP, check
8854 				 * if we need to save off the start/end
8855 				 */
8856 				if (rack->rc_last_tlp_acked_set &&
8857 				    (is_rsm_inside_declared_tlp_block(rack, rsm))) {
8858 					    /*
8859 					     * We already turned this on since this block is inside
8860 					     * the previous one was a partially sack now we
8861 					     * are getting another one (maybe all of it).
8862 					     */
8863 					    rack_log_dsack_event(rack, 10, __LINE__, rsm->r_start, rsm->r_end);
8864 					    /*
8865 					     * Lets make sure we have all of it though.
8866 					     */
8867 					    if (SEQ_LT(rsm->r_start, rack->r_ctl.last_tlp_acked_start)) {
8868 						    rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8869 						    rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8870 									 rack->r_ctl.last_tlp_acked_end);
8871 					    }
8872 					    if (SEQ_GT(rsm->r_end, rack->r_ctl.last_tlp_acked_end)) {
8873 						    rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8874 						    rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8875 									 rack->r_ctl.last_tlp_acked_end);
8876 					    }
8877 				    } else {
8878 					    rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8879 					    rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8880 					    rack->rc_last_tlp_acked_set = 1;
8881 					    rack->rc_last_tlp_past_cumack = 0;
8882 					    rack_log_dsack_event(rack, 8, __LINE__, rsm->r_start, rsm->r_end);
8883 				    }
8884 			}
8885 			/**
8886 			 * In this case nrsm becomes
8887 			 * nrsm->r_start = end;
8888 			 * nrsm->r_end = rsm->r_end;
8889 			 * which is un-acked.
8890 			 * <and>
8891 			 * rsm->r_end = nrsm->r_start;
8892 			 * i.e. the remaining un-acked
8893 			 * piece is left on the left
8894 			 * hand side.
8895 			 *
8896 			 * So we start like this
8897 			 * rsm      |----------| (not acked)
8898 			 * sackblk  |---|
8899 			 * build it so we have
8900 			 * rsm      |---|         (acked)
8901 			 * nrsm         |------|  (not acked)
8902 			 */
8903 			counter_u64_add(rack_sack_splits, 1);
8904 			rack_clone_rsm(rack, nrsm, rsm, end);
8905 			rsm->r_flags &= (~RACK_HAS_FIN);
8906 			rsm->r_just_ret = 0;
8907 			insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
8908 #ifdef INVARIANTS
8909 			if (insret != NULL) {
8910 				panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
8911 				      nrsm, insret, rack, rsm);
8912 			}
8913 #endif
8914 			if (rsm->r_in_tmap) {
8915 				TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
8916 				nrsm->r_in_tmap = 1;
8917 			}
8918 			nrsm->r_dupack = 0;
8919 			rack_log_retran_reason(rack, nrsm, __LINE__, 0, 2);
8920 			rack_update_rtt(tp, rack, rsm, to, cts, SACKED, 0);
8921 			changed += (rsm->r_end - rsm->r_start);
8922 			rack->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start);
8923 			if (rsm->r_in_tmap) /* should be true */
8924 				rack_log_sack_passed(tp, rack, rsm);
8925 			/* Is Reordering occuring? */
8926 			if (rsm->r_flags & RACK_SACK_PASSED) {
8927 				rsm->r_flags &= ~RACK_SACK_PASSED;
8928 				counter_u64_add(rack_reorder_seen, 1);
8929 				rack->r_ctl.rc_reorder_ts = cts;
8930 			}
8931 			if (rack->app_limited_needs_set)
8932 				rack_need_set_test(tp, rack, rsm, tp->snd_una, __LINE__, RACK_USE_END);
8933 			rsm->r_ack_arrival = rack_to_usec_ts(&rack->r_ctl.act_rcv_time);
8934 			rsm->r_flags |= RACK_ACKED;
8935 			rack_log_map_chg(tp, rack, NULL, rsm, nrsm, MAP_SACK_M5, end, __LINE__);
8936 			if (rsm->r_in_tmap) {
8937 				TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
8938 				rsm->r_in_tmap = 0;
8939 			}
8940 		}
8941 	} else if (start != end){
8942 		/*
8943 		 * The block was already acked.
8944 		 */
8945 		counter_u64_add(rack_sack_skipped_acked, 1);
8946 		moved++;
8947 	}
8948 out:
8949 	if (rsm &&
8950 	    ((rsm->r_flags & RACK_TLP) == 0) &&
8951 	    (rsm->r_flags & RACK_ACKED)) {
8952 		/*
8953 		 * Now can we merge where we worked
8954 		 * with either the previous or
8955 		 * next block?
8956 		 */
8957 		next = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8958 		while (next) {
8959 			if (next->r_flags & RACK_TLP)
8960 				break;
8961 			if (next->r_flags & RACK_ACKED) {
8962 			/* yep this and next can be merged */
8963 				rsm = rack_merge_rsm(rack, rsm, next);
8964 				next = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8965 			} else
8966 				break;
8967 		}
8968 		/* Now what about the previous? */
8969 		prev = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8970 		while (prev) {
8971 			if (prev->r_flags & RACK_TLP)
8972 				break;
8973 			if (prev->r_flags & RACK_ACKED) {
8974 				/* yep the previous and this can be merged */
8975 				rsm = rack_merge_rsm(rack, prev, rsm);
8976 				prev = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8977 			} else
8978 				break;
8979 		}
8980 	}
8981 	if (used_ref == 0) {
8982 		counter_u64_add(rack_sack_proc_all, 1);
8983 	} else {
8984 		counter_u64_add(rack_sack_proc_short, 1);
8985 	}
8986 	/* Save off the next one for quick reference. */
8987 	if (rsm)
8988 		nrsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8989 	else
8990 		nrsm = NULL;
8991 	*prsm = rack->r_ctl.rc_sacklast = nrsm;
8992 	/* Pass back the moved. */
8993 	*moved_two = moved;
8994 	return (changed);
8995 }
8996 
8997 static void inline
8998 rack_peer_reneges(struct tcp_rack *rack, struct rack_sendmap *rsm, tcp_seq th_ack)
8999 {
9000 	struct rack_sendmap *tmap;
9001 
9002 	tmap = NULL;
9003 	while (rsm && (rsm->r_flags & RACK_ACKED)) {
9004 		/* Its no longer sacked, mark it so */
9005 		rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
9006 #ifdef INVARIANTS
9007 		if (rsm->r_in_tmap) {
9008 			panic("rack:%p rsm:%p flags:0x%x in tmap?",
9009 			      rack, rsm, rsm->r_flags);
9010 		}
9011 #endif
9012 		rsm->r_flags &= ~(RACK_ACKED|RACK_SACK_PASSED|RACK_WAS_SACKPASS);
9013 		/* Rebuild it into our tmap */
9014 		if (tmap == NULL) {
9015 			TAILQ_INSERT_HEAD(&rack->r_ctl.rc_tmap, rsm, r_tnext);
9016 			tmap = rsm;
9017 		} else {
9018 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, tmap, rsm, r_tnext);
9019 			tmap = rsm;
9020 		}
9021 		tmap->r_in_tmap = 1;
9022 		rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
9023 	}
9024 	/*
9025 	 * Now lets possibly clear the sack filter so we start
9026 	 * recognizing sacks that cover this area.
9027 	 */
9028 	sack_filter_clear(&rack->r_ctl.rack_sf, th_ack);
9029 
9030 }
9031 
9032 static void
9033 rack_do_decay(struct tcp_rack *rack)
9034 {
9035 	struct timeval res;
9036 
9037 #define	timersub(tvp, uvp, vvp)						\
9038 	do {								\
9039 		(vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec;		\
9040 		(vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec;	\
9041 		if ((vvp)->tv_usec < 0) {				\
9042 			(vvp)->tv_sec--;				\
9043 			(vvp)->tv_usec += 1000000;			\
9044 		}							\
9045 	} while (0)
9046 
9047 	timersub(&rack->r_ctl.act_rcv_time, &rack->r_ctl.rc_last_time_decay, &res);
9048 #undef timersub
9049 
9050 	rack->r_ctl.input_pkt++;
9051 	if ((rack->rc_in_persist) ||
9052 	    (res.tv_sec >= 1) ||
9053 	    (rack->rc_tp->snd_max == rack->rc_tp->snd_una)) {
9054 		/*
9055 		 * Check for decay of non-SAD,
9056 		 * we want all SAD detection metrics to
9057 		 * decay 1/4 per second (or more) passed.
9058 		 */
9059 		uint32_t pkt_delta;
9060 
9061 		pkt_delta = rack->r_ctl.input_pkt - rack->r_ctl.saved_input_pkt;
9062 		/* Update our saved tracking values */
9063 		rack->r_ctl.saved_input_pkt = rack->r_ctl.input_pkt;
9064 		rack->r_ctl.rc_last_time_decay = rack->r_ctl.act_rcv_time;
9065 		/* Now do we escape without decay? */
9066 #ifdef NETFLIX_EXP_DETECTION
9067 		if (rack->rc_in_persist ||
9068 		    (rack->rc_tp->snd_max == rack->rc_tp->snd_una) ||
9069 		    (pkt_delta < tcp_sad_low_pps)){
9070 			/*
9071 			 * We don't decay idle connections
9072 			 * or ones that have a low input pps.
9073 			 */
9074 			return;
9075 		}
9076 		/* Decay the counters */
9077 		rack->r_ctl.ack_count = ctf_decay_count(rack->r_ctl.ack_count,
9078 							tcp_sad_decay_val);
9079 		rack->r_ctl.sack_count = ctf_decay_count(rack->r_ctl.sack_count,
9080 							 tcp_sad_decay_val);
9081 		rack->r_ctl.sack_moved_extra = ctf_decay_count(rack->r_ctl.sack_moved_extra,
9082 							       tcp_sad_decay_val);
9083 		rack->r_ctl.sack_noextra_move = ctf_decay_count(rack->r_ctl.sack_noextra_move,
9084 								tcp_sad_decay_val);
9085 #endif
9086 	}
9087 }
9088 
9089 static void
9090 rack_process_to_cumack(struct tcpcb *tp, struct tcp_rack *rack, register uint32_t th_ack, uint32_t cts, struct tcpopt *to)
9091 {
9092 	struct rack_sendmap *rsm, *rm;
9093 
9094 	/*
9095 	 * The ACK point is advancing to th_ack, we must drop off
9096 	 * the packets in the rack log and calculate any eligble
9097 	 * RTT's.
9098 	 */
9099 	rack->r_wanted_output = 1;
9100 
9101 	/* Tend any TLP that has been marked for 1/2 the seq space (its old)  */
9102 	if ((rack->rc_last_tlp_acked_set == 1)&&
9103 	    (rack->rc_last_tlp_past_cumack == 1) &&
9104 	    (SEQ_GT(rack->r_ctl.last_tlp_acked_start, th_ack))) {
9105 		/*
9106 		 * We have reached the point where our last rack
9107 		 * tlp retransmit sequence is ahead of the cum-ack.
9108 		 * This can only happen when the cum-ack moves all
9109 		 * the way around (its been a full 2^^31+1 bytes
9110 		 * or more since we sent a retransmitted TLP). Lets
9111 		 * turn off the valid flag since its not really valid.
9112 		 *
9113 		 * Note since sack's also turn on this event we have
9114 		 * a complication, we have to wait to age it out until
9115 		 * the cum-ack is by the TLP before checking which is
9116 		 * what the next else clause does.
9117 		 */
9118 		rack_log_dsack_event(rack, 9, __LINE__,
9119 				     rack->r_ctl.last_tlp_acked_start,
9120 				     rack->r_ctl.last_tlp_acked_end);
9121 		rack->rc_last_tlp_acked_set = 0;
9122 		rack->rc_last_tlp_past_cumack = 0;
9123 	} else if ((rack->rc_last_tlp_acked_set == 1) &&
9124 		   (rack->rc_last_tlp_past_cumack == 0) &&
9125 		   (SEQ_GEQ(th_ack, rack->r_ctl.last_tlp_acked_end))) {
9126 		/*
9127 		 * It is safe to start aging TLP's out.
9128 		 */
9129 		rack->rc_last_tlp_past_cumack = 1;
9130 	}
9131 	/* We do the same for the tlp send seq as well */
9132 	if ((rack->rc_last_sent_tlp_seq_valid == 1) &&
9133 	    (rack->rc_last_sent_tlp_past_cumack == 1) &&
9134 	    (SEQ_GT(rack->r_ctl.last_sent_tlp_seq,  th_ack))) {
9135 		rack_log_dsack_event(rack, 9, __LINE__,
9136 				     rack->r_ctl.last_sent_tlp_seq,
9137 				     (rack->r_ctl.last_sent_tlp_seq +
9138 				      rack->r_ctl.last_sent_tlp_len));
9139 		rack->rc_last_sent_tlp_seq_valid = 0;
9140 		rack->rc_last_sent_tlp_past_cumack = 0;
9141 	} else if ((rack->rc_last_sent_tlp_seq_valid == 1) &&
9142 		   (rack->rc_last_sent_tlp_past_cumack == 0) &&
9143 		   (SEQ_GEQ(th_ack, rack->r_ctl.last_sent_tlp_seq))) {
9144 		/*
9145 		 * It is safe to start aging TLP's send.
9146 		 */
9147 		rack->rc_last_sent_tlp_past_cumack = 1;
9148 	}
9149 more:
9150 	rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
9151 	if (rsm == NULL) {
9152 		if ((th_ack - 1) == tp->iss) {
9153 			/*
9154 			 * For the SYN incoming case we will not
9155 			 * have called tcp_output for the sending of
9156 			 * the SYN, so there will be no map. All
9157 			 * other cases should probably be a panic.
9158 			 */
9159 			return;
9160 		}
9161 		if (tp->t_flags & TF_SENTFIN) {
9162 			/* if we sent a FIN we often will not have map */
9163 			return;
9164 		}
9165 #ifdef INVARIANTS
9166 		panic("No rack map tp:%p for state:%d ack:%u rack:%p snd_una:%u snd_max:%u snd_nxt:%u\n",
9167 		      tp,
9168 		      tp->t_state, th_ack, rack,
9169 		      tp->snd_una, tp->snd_max, tp->snd_nxt);
9170 #endif
9171 		return;
9172 	}
9173 	if (SEQ_LT(th_ack, rsm->r_start)) {
9174 		/* Huh map is missing this */
9175 #ifdef INVARIANTS
9176 		printf("Rack map starts at r_start:%u for th_ack:%u huh? ts:%d rs:%d\n",
9177 		       rsm->r_start,
9178 		       th_ack, tp->t_state, rack->r_state);
9179 #endif
9180 		return;
9181 	}
9182 	rack_update_rtt(tp, rack, rsm, to, cts, CUM_ACKED, th_ack);
9183 
9184 	/* Now was it a retransmitted TLP? */
9185 	if ((rsm->r_flags & RACK_TLP) &&
9186 	    (rsm->r_rtr_cnt > 1)) {
9187 		/*
9188 		 * Yes, this rsm was a TLP and retransmitted, remember that
9189 		 * since if a DSACK comes back on this we don't want
9190 		 * to think of it as a reordered segment. This may
9191 		 * get updated again with possibly even other TLPs
9192 		 * in flight, but thats ok. Only when we don't send
9193 		 * a retransmitted TLP for 1/2 the sequences space
9194 		 * will it get turned off (above).
9195 		 */
9196 		if (rack->rc_last_tlp_acked_set &&
9197 		    (is_rsm_inside_declared_tlp_block(rack, rsm))) {
9198 			/*
9199 			 * We already turned this on since the end matches,
9200 			 * the previous one was a partially ack now we
9201 			 * are getting another one (maybe all of it).
9202 			 */
9203 			rack_log_dsack_event(rack, 10, __LINE__, rsm->r_start, rsm->r_end);
9204 			/*
9205 			 * Lets make sure we have all of it though.
9206 			 */
9207 			if (SEQ_LT(rsm->r_start, rack->r_ctl.last_tlp_acked_start)) {
9208 				rack->r_ctl.last_tlp_acked_start = rsm->r_start;
9209 				rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
9210 						     rack->r_ctl.last_tlp_acked_end);
9211 			}
9212 			if (SEQ_GT(rsm->r_end, rack->r_ctl.last_tlp_acked_end)) {
9213 				rack->r_ctl.last_tlp_acked_end = rsm->r_end;
9214 				rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
9215 						     rack->r_ctl.last_tlp_acked_end);
9216 			}
9217 		} else {
9218 			rack->rc_last_tlp_past_cumack = 1;
9219 			rack->r_ctl.last_tlp_acked_start = rsm->r_start;
9220 			rack->r_ctl.last_tlp_acked_end = rsm->r_end;
9221 			rack->rc_last_tlp_acked_set = 1;
9222 			rack_log_dsack_event(rack, 8, __LINE__, rsm->r_start, rsm->r_end);
9223 		}
9224 	}
9225 	/* Now do we consume the whole thing? */
9226 	if (SEQ_GEQ(th_ack, rsm->r_end)) {
9227 		/* Its all consumed. */
9228 		uint32_t left;
9229 		uint8_t newly_acked;
9230 
9231 		rack_log_map_chg(tp, rack, NULL, rsm, NULL, MAP_FREE, rsm->r_end, __LINE__);
9232 		rack->r_ctl.rc_holes_rxt -= rsm->r_rtr_bytes;
9233 		rsm->r_rtr_bytes = 0;
9234 		/* Record the time of highest cumack sent */
9235 		rack->r_ctl.rc_gp_cumack_ts = rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
9236 		rm = RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
9237 #ifdef INVARIANTS
9238 		if (rm != rsm) {
9239 			panic("removing head in rack:%p rsm:%p rm:%p",
9240 			      rack, rsm, rm);
9241 		}
9242 #endif
9243 		if (rsm->r_in_tmap) {
9244 			TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
9245 			rsm->r_in_tmap = 0;
9246 		}
9247 		newly_acked = 1;
9248 		if (rsm->r_flags & RACK_ACKED) {
9249 			/*
9250 			 * It was acked on the scoreboard -- remove
9251 			 * it from total
9252 			 */
9253 			rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
9254 			newly_acked = 0;
9255 		} else if (rsm->r_flags & RACK_SACK_PASSED) {
9256 			/*
9257 			 * There are segments ACKED on the
9258 			 * scoreboard further up. We are seeing
9259 			 * reordering.
9260 			 */
9261 			rsm->r_flags &= ~RACK_SACK_PASSED;
9262 			counter_u64_add(rack_reorder_seen, 1);
9263 			rsm->r_ack_arrival = rack_to_usec_ts(&rack->r_ctl.act_rcv_time);
9264 			rsm->r_flags |= RACK_ACKED;
9265 			rack->r_ctl.rc_reorder_ts = cts;
9266 			if (rack->r_ent_rec_ns) {
9267 				/*
9268 				 * We have sent no more, and we saw an sack
9269 				 * then ack arrive.
9270 				 */
9271 				rack->r_might_revert = 1;
9272 			}
9273 		}
9274 		if ((rsm->r_flags & RACK_TO_REXT) &&
9275 		    (tp->t_flags & TF_RCVD_TSTMP) &&
9276 		    (to->to_flags & TOF_TS) &&
9277 		    (to->to_tsecr != 0) &&
9278 		    (tp->t_flags & TF_PREVVALID)) {
9279 			/*
9280 			 * We can use the timestamp to see
9281 			 * if this retransmission was from the
9282 			 * first transmit. If so we made a mistake.
9283 			 */
9284 			tp->t_flags &= ~TF_PREVVALID;
9285 			if (to->to_tsecr == rack_ts_to_msec(rsm->r_tim_lastsent[0])) {
9286 				/* The first transmit is what this ack is for */
9287 				rack_cong_signal(tp, CC_RTO_ERR, th_ack);
9288 			}
9289 		}
9290 		left = th_ack - rsm->r_end;
9291 		if (rack->app_limited_needs_set && newly_acked)
9292 			rack_need_set_test(tp, rack, rsm, th_ack, __LINE__, RACK_USE_END_OR_THACK);
9293 		/* Free back to zone */
9294 		rack_free(rack, rsm);
9295 		if (left) {
9296 			goto more;
9297 		}
9298 		/* Check for reneging */
9299 		rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
9300 		if (rsm && (rsm->r_flags & RACK_ACKED) && (th_ack == rsm->r_start)) {
9301 			/*
9302 			 * The peer has moved snd_una up to
9303 			 * the edge of this send, i.e. one
9304 			 * that it had previously acked. The only
9305 			 * way that can be true if the peer threw
9306 			 * away data (space issues) that it had
9307 			 * previously sacked (else it would have
9308 			 * given us snd_una up to (rsm->r_end).
9309 			 * We need to undo the acked markings here.
9310 			 *
9311 			 * Note we have to look to make sure th_ack is
9312 			 * our rsm->r_start in case we get an old ack
9313 			 * where th_ack is behind snd_una.
9314 			 */
9315 			rack_peer_reneges(rack, rsm, th_ack);
9316 		}
9317 		return;
9318 	}
9319 	if (rsm->r_flags & RACK_ACKED) {
9320 		/*
9321 		 * It was acked on the scoreboard -- remove it from
9322 		 * total for the part being cum-acked.
9323 		 */
9324 		rack->r_ctl.rc_sacked -= (th_ack - rsm->r_start);
9325 	}
9326 	/*
9327 	 * Clear the dup ack count for
9328 	 * the piece that remains.
9329 	 */
9330 	rsm->r_dupack = 0;
9331 	rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
9332 	if (rsm->r_rtr_bytes) {
9333 		/*
9334 		 * It was retransmitted adjust the
9335 		 * sack holes for what was acked.
9336 		 */
9337 		int ack_am;
9338 
9339 		ack_am = (th_ack - rsm->r_start);
9340 		if (ack_am >= rsm->r_rtr_bytes) {
9341 			rack->r_ctl.rc_holes_rxt -= ack_am;
9342 			rsm->r_rtr_bytes -= ack_am;
9343 		}
9344 	}
9345 	/*
9346 	 * Update where the piece starts and record
9347 	 * the time of send of highest cumack sent.
9348 	 */
9349 	rack->r_ctl.rc_gp_cumack_ts = rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
9350 	rack_log_map_chg(tp, rack, NULL, rsm, NULL, MAP_TRIM_HEAD, th_ack, __LINE__);
9351 	/* Now we need to move our offset forward too */
9352 	if (rsm->m && (rsm->orig_m_len != rsm->m->m_len)) {
9353 		/* Fix up the orig_m_len and possibly the mbuf offset */
9354 		rack_adjust_orig_mlen(rsm);
9355 	}
9356 	rsm->soff += (th_ack - rsm->r_start);
9357 	rsm->r_start = th_ack;
9358 	/* Now do we need to move the mbuf fwd too? */
9359 	if (rsm->m) {
9360 		while (rsm->soff >= rsm->m->m_len) {
9361 			rsm->soff -= rsm->m->m_len;
9362 			rsm->m = rsm->m->m_next;
9363 			KASSERT((rsm->m != NULL),
9364 				(" nrsm:%p hit at soff:%u null m",
9365 				 rsm, rsm->soff));
9366 		}
9367 		rsm->orig_m_len = rsm->m->m_len;
9368 	}
9369 	if (rack->app_limited_needs_set)
9370 		rack_need_set_test(tp, rack, rsm, tp->snd_una, __LINE__, RACK_USE_BEG);
9371 }
9372 
9373 static void
9374 rack_handle_might_revert(struct tcpcb *tp, struct tcp_rack *rack)
9375 {
9376 	struct rack_sendmap *rsm;
9377 	int sack_pass_fnd = 0;
9378 
9379 	if (rack->r_might_revert) {
9380 		/*
9381 		 * Ok we have reordering, have not sent anything, we
9382 		 * might want to revert the congestion state if nothing
9383 		 * further has SACK_PASSED on it. Lets check.
9384 		 *
9385 		 * We also get here when we have DSACKs come in for
9386 		 * all the data that we FR'd. Note that a rxt or tlp
9387 		 * timer clears this from happening.
9388 		 */
9389 
9390 		TAILQ_FOREACH(rsm, &rack->r_ctl.rc_tmap, r_tnext) {
9391 			if (rsm->r_flags & RACK_SACK_PASSED) {
9392 				sack_pass_fnd = 1;
9393 				break;
9394 			}
9395 		}
9396 		if (sack_pass_fnd == 0) {
9397 			/*
9398 			 * We went into recovery
9399 			 * incorrectly due to reordering!
9400 			 */
9401 			int orig_cwnd;
9402 
9403 			rack->r_ent_rec_ns = 0;
9404 			orig_cwnd = tp->snd_cwnd;
9405 			tp->snd_cwnd = rack->r_ctl.rc_cwnd_at_erec;
9406 			tp->snd_ssthresh = rack->r_ctl.rc_ssthresh_at_erec;
9407 			tp->snd_recover = tp->snd_una;
9408 			rack_log_to_prr(rack, 14, orig_cwnd);
9409 			EXIT_RECOVERY(tp->t_flags);
9410 		}
9411 		rack->r_might_revert = 0;
9412 	}
9413 }
9414 
9415 #ifdef NETFLIX_EXP_DETECTION
9416 static void
9417 rack_do_detection(struct tcpcb *tp, struct tcp_rack *rack,  uint32_t bytes_this_ack, uint32_t segsiz)
9418 {
9419 	if ((rack->do_detection || tcp_force_detection) &&
9420 	    tcp_sack_to_ack_thresh &&
9421 	    tcp_sack_to_move_thresh &&
9422 	    ((rack->r_ctl.rc_num_maps_alloced > tcp_map_minimum) || rack->sack_attack_disable)) {
9423 		/*
9424 		 * We have thresholds set to find
9425 		 * possible attackers and disable sack.
9426 		 * Check them.
9427 		 */
9428 		uint64_t ackratio, moveratio, movetotal;
9429 
9430 		/* Log detecting */
9431 		rack_log_sad(rack, 1);
9432 		ackratio = (uint64_t)(rack->r_ctl.sack_count);
9433 		ackratio *= (uint64_t)(1000);
9434 		if (rack->r_ctl.ack_count)
9435 			ackratio /= (uint64_t)(rack->r_ctl.ack_count);
9436 		else {
9437 			/* We really should not hit here */
9438 			ackratio = 1000;
9439 		}
9440 		if ((rack->sack_attack_disable == 0) &&
9441 		    (ackratio > rack_highest_sack_thresh_seen))
9442 			rack_highest_sack_thresh_seen = (uint32_t)ackratio;
9443 		movetotal = rack->r_ctl.sack_moved_extra;
9444 		movetotal += rack->r_ctl.sack_noextra_move;
9445 		moveratio = rack->r_ctl.sack_moved_extra;
9446 		moveratio *= (uint64_t)1000;
9447 		if (movetotal)
9448 			moveratio /= movetotal;
9449 		else {
9450 			/* No moves, thats pretty good */
9451 			moveratio = 0;
9452 		}
9453 		if ((rack->sack_attack_disable == 0) &&
9454 		    (moveratio > rack_highest_move_thresh_seen))
9455 			rack_highest_move_thresh_seen = (uint32_t)moveratio;
9456 		if (rack->sack_attack_disable == 0) {
9457 			if ((ackratio > tcp_sack_to_ack_thresh) &&
9458 			    (moveratio > tcp_sack_to_move_thresh)) {
9459 				/* Disable sack processing */
9460 				rack->sack_attack_disable = 1;
9461 				if (rack->r_rep_attack == 0) {
9462 					rack->r_rep_attack = 1;
9463 					counter_u64_add(rack_sack_attacks_detected, 1);
9464 				}
9465 				if (tcp_attack_on_turns_on_logging) {
9466 					/*
9467 					 * Turn on logging, used for debugging
9468 					 * false positives.
9469 					 */
9470 					rack->rc_tp->t_logstate = tcp_attack_on_turns_on_logging;
9471 				}
9472 				/* Clamp the cwnd at flight size */
9473 				rack->r_ctl.rc_saved_cwnd = rack->rc_tp->snd_cwnd;
9474 				rack->rc_tp->snd_cwnd = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
9475 				rack_log_sad(rack, 2);
9476 			}
9477 		} else {
9478 			/* We are sack-disabled check for false positives */
9479 			if ((ackratio <= tcp_restoral_thresh) ||
9480 			    (rack->r_ctl.rc_num_maps_alloced  < tcp_map_minimum)) {
9481 				rack->sack_attack_disable = 0;
9482 				rack_log_sad(rack, 3);
9483 				/* Restart counting */
9484 				rack->r_ctl.sack_count = 0;
9485 				rack->r_ctl.sack_moved_extra = 0;
9486 				rack->r_ctl.sack_noextra_move = 1;
9487 				rack->r_ctl.ack_count = max(1,
9488 				      (bytes_this_ack / segsiz));
9489 
9490 				if (rack->r_rep_reverse == 0) {
9491 					rack->r_rep_reverse = 1;
9492 					counter_u64_add(rack_sack_attacks_reversed, 1);
9493 				}
9494 				/* Restore the cwnd */
9495 				if (rack->r_ctl.rc_saved_cwnd > rack->rc_tp->snd_cwnd)
9496 					rack->rc_tp->snd_cwnd = rack->r_ctl.rc_saved_cwnd;
9497 			}
9498 		}
9499 	}
9500 }
9501 #endif
9502 
9503 static int
9504 rack_note_dsack(struct tcp_rack *rack, tcp_seq start, tcp_seq end)
9505 {
9506 
9507 	uint32_t am, l_end;
9508 	int was_tlp = 0;
9509 
9510 	if (SEQ_GT(end, start))
9511 		am = end - start;
9512 	else
9513 		am = 0;
9514 	if ((rack->rc_last_tlp_acked_set ) &&
9515 	    (SEQ_GEQ(start, rack->r_ctl.last_tlp_acked_start)) &&
9516 	    (SEQ_LEQ(end, rack->r_ctl.last_tlp_acked_end))) {
9517 		/*
9518 		 * The DSACK is because of a TLP which we don't
9519 		 * do anything with the reordering window over since
9520 		 * it was not reordering that caused the DSACK but
9521 		 * our previous retransmit TLP.
9522 		 */
9523 		rack_log_dsack_event(rack, 7, __LINE__, start, end);
9524 		was_tlp = 1;
9525 		goto skip_dsack_round;
9526 	}
9527 	if (rack->rc_last_sent_tlp_seq_valid) {
9528 		l_end = rack->r_ctl.last_sent_tlp_seq + rack->r_ctl.last_sent_tlp_len;
9529 		if (SEQ_GEQ(start, rack->r_ctl.last_sent_tlp_seq) &&
9530 		    (SEQ_LEQ(end, l_end))) {
9531 			/*
9532 			 * This dsack is from the last sent TLP, ignore it
9533 			 * for reordering purposes.
9534 			 */
9535 			rack_log_dsack_event(rack, 7, __LINE__, start, end);
9536 			was_tlp = 1;
9537 			goto skip_dsack_round;
9538 		}
9539 	}
9540 	if (rack->rc_dsack_round_seen == 0) {
9541 		rack->rc_dsack_round_seen = 1;
9542 		rack->r_ctl.dsack_round_end = rack->rc_tp->snd_max;
9543 		rack->r_ctl.num_dsack++;
9544 		rack->r_ctl.dsack_persist = 16;	/* 16 is from the standard */
9545 		rack_log_dsack_event(rack, 2, __LINE__, 0, 0);
9546 	}
9547 skip_dsack_round:
9548 	/*
9549 	 * We keep track of how many DSACK blocks we get
9550 	 * after a recovery incident.
9551 	 */
9552 	rack->r_ctl.dsack_byte_cnt += am;
9553 	if (!IN_FASTRECOVERY(rack->rc_tp->t_flags) &&
9554 	    rack->r_ctl.retran_during_recovery &&
9555 	    (rack->r_ctl.dsack_byte_cnt >= rack->r_ctl.retran_during_recovery)) {
9556 		/*
9557 		 * False recovery most likely culprit is reordering. If
9558 		 * nothing else is missing we need to revert.
9559 		 */
9560 		rack->r_might_revert = 1;
9561 		rack_handle_might_revert(rack->rc_tp, rack);
9562 		rack->r_might_revert = 0;
9563 		rack->r_ctl.retran_during_recovery = 0;
9564 		rack->r_ctl.dsack_byte_cnt = 0;
9565 	}
9566 	return (was_tlp);
9567 }
9568 
9569 static void
9570 rack_update_prr(struct tcpcb *tp, struct tcp_rack *rack, uint32_t changed, tcp_seq th_ack)
9571 {
9572 	/* Deal with changed and PRR here (in recovery only) */
9573 	uint32_t pipe, snd_una;
9574 
9575 	rack->r_ctl.rc_prr_delivered += changed;
9576 
9577 	if (sbavail(&rack->rc_inp->inp_socket->so_snd) <= (tp->snd_max - tp->snd_una)) {
9578 		/*
9579 		 * It is all outstanding, we are application limited
9580 		 * and thus we don't need more room to send anything.
9581 		 * Note we use tp->snd_una here and not th_ack because
9582 		 * the data as yet not been cut from the sb.
9583 		 */
9584 		rack->r_ctl.rc_prr_sndcnt = 0;
9585 		return;
9586 	}
9587 	/* Compute prr_sndcnt */
9588 	if (SEQ_GT(tp->snd_una, th_ack)) {
9589 		snd_una = tp->snd_una;
9590 	} else {
9591 		snd_una = th_ack;
9592 	}
9593 	pipe = ((tp->snd_max - snd_una) - rack->r_ctl.rc_sacked) + rack->r_ctl.rc_holes_rxt;
9594 	if (pipe > tp->snd_ssthresh) {
9595 		long sndcnt;
9596 
9597 		sndcnt = rack->r_ctl.rc_prr_delivered * tp->snd_ssthresh;
9598 		if (rack->r_ctl.rc_prr_recovery_fs > 0)
9599 			sndcnt /= (long)rack->r_ctl.rc_prr_recovery_fs;
9600 		else {
9601 			rack->r_ctl.rc_prr_sndcnt = 0;
9602 			rack_log_to_prr(rack, 9, 0);
9603 			sndcnt = 0;
9604 		}
9605 		sndcnt++;
9606 		if (sndcnt > (long)rack->r_ctl.rc_prr_out)
9607 			sndcnt -= rack->r_ctl.rc_prr_out;
9608 		else
9609 			sndcnt = 0;
9610 		rack->r_ctl.rc_prr_sndcnt = sndcnt;
9611 		rack_log_to_prr(rack, 10, 0);
9612 	} else {
9613 		uint32_t limit;
9614 
9615 		if (rack->r_ctl.rc_prr_delivered > rack->r_ctl.rc_prr_out)
9616 			limit = (rack->r_ctl.rc_prr_delivered - rack->r_ctl.rc_prr_out);
9617 		else
9618 			limit = 0;
9619 		if (changed > limit)
9620 			limit = changed;
9621 		limit += ctf_fixed_maxseg(tp);
9622 		if (tp->snd_ssthresh > pipe) {
9623 			rack->r_ctl.rc_prr_sndcnt = min((tp->snd_ssthresh - pipe), limit);
9624 			rack_log_to_prr(rack, 11, 0);
9625 		} else {
9626 			rack->r_ctl.rc_prr_sndcnt = min(0, limit);
9627 			rack_log_to_prr(rack, 12, 0);
9628 		}
9629 	}
9630 }
9631 
9632 static void
9633 rack_log_ack(struct tcpcb *tp, struct tcpopt *to, struct tcphdr *th, int entered_recovery, int dup_ack_struck)
9634 {
9635 	uint32_t changed;
9636 	struct tcp_rack *rack;
9637 	struct rack_sendmap *rsm;
9638 	struct sackblk sack, sack_blocks[TCP_MAX_SACK + 1];
9639 	register uint32_t th_ack;
9640 	int32_t i, j, k, num_sack_blks = 0;
9641 	uint32_t cts, acked, ack_point, sack_changed = 0;
9642 	int loop_start = 0, moved_two = 0;
9643 	uint32_t tsused;
9644 
9645 
9646 	INP_WLOCK_ASSERT(tp->t_inpcb);
9647 	if (th->th_flags & TH_RST) {
9648 		/* We don't log resets */
9649 		return;
9650 	}
9651 	rack = (struct tcp_rack *)tp->t_fb_ptr;
9652 	cts = tcp_get_usecs(NULL);
9653 	rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
9654 	changed = 0;
9655 	th_ack = th->th_ack;
9656 	if (rack->sack_attack_disable == 0)
9657 		rack_do_decay(rack);
9658 	if (BYTES_THIS_ACK(tp, th) >= ctf_fixed_maxseg(rack->rc_tp)) {
9659 		/*
9660 		 * You only get credit for
9661 		 * MSS and greater (and you get extra
9662 		 * credit for larger cum-ack moves).
9663 		 */
9664 		int ac;
9665 
9666 		ac = BYTES_THIS_ACK(tp, th) / ctf_fixed_maxseg(rack->rc_tp);
9667 		rack->r_ctl.ack_count += ac;
9668 		counter_u64_add(rack_ack_total, ac);
9669 	}
9670 	if (rack->r_ctl.ack_count > 0xfff00000) {
9671 		/*
9672 		 * reduce the number to keep us under
9673 		 * a uint32_t.
9674 		 */
9675 		rack->r_ctl.ack_count /= 2;
9676 		rack->r_ctl.sack_count /= 2;
9677 	}
9678 	if (SEQ_GT(th_ack, tp->snd_una)) {
9679 		rack_log_progress_event(rack, tp, ticks, PROGRESS_UPDATE, __LINE__);
9680 		tp->t_acktime = ticks;
9681 	}
9682 	if (rsm && SEQ_GT(th_ack, rsm->r_start))
9683 		changed = th_ack - rsm->r_start;
9684 	if (changed) {
9685 		rack_process_to_cumack(tp, rack, th_ack, cts, to);
9686 	}
9687 	if ((to->to_flags & TOF_SACK) == 0) {
9688 		/* We are done nothing left and no sack. */
9689 		rack_handle_might_revert(tp, rack);
9690 		/*
9691 		 * For cases where we struck a dup-ack
9692 		 * with no SACK, add to the changes so
9693 		 * PRR will work right.
9694 		 */
9695 		if (dup_ack_struck && (changed == 0)) {
9696 			changed += ctf_fixed_maxseg(rack->rc_tp);
9697 		}
9698 		goto out;
9699 	}
9700 	/* Sack block processing */
9701 	if (SEQ_GT(th_ack, tp->snd_una))
9702 		ack_point = th_ack;
9703 	else
9704 		ack_point = tp->snd_una;
9705 	for (i = 0; i < to->to_nsacks; i++) {
9706 		bcopy((to->to_sacks + i * TCPOLEN_SACK),
9707 		      &sack, sizeof(sack));
9708 		sack.start = ntohl(sack.start);
9709 		sack.end = ntohl(sack.end);
9710 		if (SEQ_GT(sack.end, sack.start) &&
9711 		    SEQ_GT(sack.start, ack_point) &&
9712 		    SEQ_LT(sack.start, tp->snd_max) &&
9713 		    SEQ_GT(sack.end, ack_point) &&
9714 		    SEQ_LEQ(sack.end, tp->snd_max)) {
9715 			sack_blocks[num_sack_blks] = sack;
9716 			num_sack_blks++;
9717 		} else if (SEQ_LEQ(sack.start, th_ack) &&
9718 			   SEQ_LEQ(sack.end, th_ack)) {
9719 			int was_tlp;
9720 
9721 			was_tlp = rack_note_dsack(rack, sack.start, sack.end);
9722 			/*
9723 			 * Its a D-SACK block.
9724 			 */
9725 			tcp_record_dsack(tp, sack.start, sack.end, was_tlp);
9726 		}
9727 	}
9728 	if (rack->rc_dsack_round_seen) {
9729 		/* Is the dsack roound over? */
9730 		if (SEQ_GEQ(th_ack, rack->r_ctl.dsack_round_end)) {
9731 			/* Yes it is */
9732 			rack->rc_dsack_round_seen = 0;
9733 			rack_log_dsack_event(rack, 3, __LINE__, 0, 0);
9734 		}
9735 	}
9736 	/*
9737 	 * Sort the SACK blocks so we can update the rack scoreboard with
9738 	 * just one pass.
9739 	 */
9740 	num_sack_blks = sack_filter_blks(&rack->r_ctl.rack_sf, sack_blocks,
9741 					 num_sack_blks, th->th_ack);
9742 	ctf_log_sack_filter(rack->rc_tp, num_sack_blks, sack_blocks);
9743 	if (num_sack_blks == 0) {
9744 		/* Nothing to sack (DSACKs?) */
9745 		goto out_with_totals;
9746 	}
9747 	if (num_sack_blks < 2) {
9748 		/* Only one, we don't need to sort */
9749 		goto do_sack_work;
9750 	}
9751 	/* Sort the sacks */
9752 	for (i = 0; i < num_sack_blks; i++) {
9753 		for (j = i + 1; j < num_sack_blks; j++) {
9754 			if (SEQ_GT(sack_blocks[i].end, sack_blocks[j].end)) {
9755 				sack = sack_blocks[i];
9756 				sack_blocks[i] = sack_blocks[j];
9757 				sack_blocks[j] = sack;
9758 			}
9759 		}
9760 	}
9761 	/*
9762 	 * Now are any of the sack block ends the same (yes some
9763 	 * implementations send these)?
9764 	 */
9765 again:
9766 	if (num_sack_blks == 0)
9767 		goto out_with_totals;
9768 	if (num_sack_blks > 1) {
9769 		for (i = 0; i < num_sack_blks; i++) {
9770 			for (j = i + 1; j < num_sack_blks; j++) {
9771 				if (sack_blocks[i].end == sack_blocks[j].end) {
9772 					/*
9773 					 * Ok these two have the same end we
9774 					 * want the smallest end and then
9775 					 * throw away the larger and start
9776 					 * again.
9777 					 */
9778 					if (SEQ_LT(sack_blocks[j].start, sack_blocks[i].start)) {
9779 						/*
9780 						 * The second block covers
9781 						 * more area use that
9782 						 */
9783 						sack_blocks[i].start = sack_blocks[j].start;
9784 					}
9785 					/*
9786 					 * Now collapse out the dup-sack and
9787 					 * lower the count
9788 					 */
9789 					for (k = (j + 1); k < num_sack_blks; k++) {
9790 						sack_blocks[j].start = sack_blocks[k].start;
9791 						sack_blocks[j].end = sack_blocks[k].end;
9792 						j++;
9793 					}
9794 					num_sack_blks--;
9795 					goto again;
9796 				}
9797 			}
9798 		}
9799 	}
9800 do_sack_work:
9801 	/*
9802 	 * First lets look to see if
9803 	 * we have retransmitted and
9804 	 * can use the transmit next?
9805 	 */
9806 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
9807 	if (rsm &&
9808 	    SEQ_GT(sack_blocks[0].end, rsm->r_start) &&
9809 	    SEQ_LT(sack_blocks[0].start, rsm->r_end)) {
9810 		/*
9811 		 * We probably did the FR and the next
9812 		 * SACK in continues as we would expect.
9813 		 */
9814 		acked = rack_proc_sack_blk(tp, rack, &sack_blocks[0], to, &rsm, cts, &moved_two);
9815 		if (acked) {
9816 			rack->r_wanted_output = 1;
9817 			changed += acked;
9818 			sack_changed += acked;
9819 		}
9820 		if (num_sack_blks == 1) {
9821 			/*
9822 			 * This is what we would expect from
9823 			 * a normal implementation to happen
9824 			 * after we have retransmitted the FR,
9825 			 * i.e the sack-filter pushes down
9826 			 * to 1 block and the next to be retransmitted
9827 			 * is the sequence in the sack block (has more
9828 			 * are acked). Count this as ACK'd data to boost
9829 			 * up the chances of recovering any false positives.
9830 			 */
9831 			rack->r_ctl.ack_count += (acked / ctf_fixed_maxseg(rack->rc_tp));
9832 			counter_u64_add(rack_ack_total, (acked / ctf_fixed_maxseg(rack->rc_tp)));
9833 			counter_u64_add(rack_express_sack, 1);
9834 			if (rack->r_ctl.ack_count > 0xfff00000) {
9835 				/*
9836 				 * reduce the number to keep us under
9837 				 * a uint32_t.
9838 				 */
9839 				rack->r_ctl.ack_count /= 2;
9840 				rack->r_ctl.sack_count /= 2;
9841 			}
9842 			goto out_with_totals;
9843 		} else {
9844 			/*
9845 			 * Start the loop through the
9846 			 * rest of blocks, past the first block.
9847 			 */
9848 			moved_two = 0;
9849 			loop_start = 1;
9850 		}
9851 	}
9852 	/* Its a sack of some sort */
9853 	rack->r_ctl.sack_count++;
9854 	if (rack->r_ctl.sack_count > 0xfff00000) {
9855 		/*
9856 		 * reduce the number to keep us under
9857 		 * a uint32_t.
9858 		 */
9859 		rack->r_ctl.ack_count /= 2;
9860 		rack->r_ctl.sack_count /= 2;
9861 	}
9862 	counter_u64_add(rack_sack_total, 1);
9863 	if (rack->sack_attack_disable) {
9864 		/* An attacker disablement is in place */
9865 		if (num_sack_blks > 1) {
9866 			rack->r_ctl.sack_count += (num_sack_blks - 1);
9867 			rack->r_ctl.sack_moved_extra++;
9868 			counter_u64_add(rack_move_some, 1);
9869 			if (rack->r_ctl.sack_moved_extra > 0xfff00000) {
9870 				rack->r_ctl.sack_moved_extra /= 2;
9871 				rack->r_ctl.sack_noextra_move /= 2;
9872 			}
9873 		}
9874 		goto out;
9875 	}
9876 	rsm = rack->r_ctl.rc_sacklast;
9877 	for (i = loop_start; i < num_sack_blks; i++) {
9878 		acked = rack_proc_sack_blk(tp, rack, &sack_blocks[i], to, &rsm, cts, &moved_two);
9879 		if (acked) {
9880 			rack->r_wanted_output = 1;
9881 			changed += acked;
9882 			sack_changed += acked;
9883 		}
9884 		if (moved_two) {
9885 			/*
9886 			 * If we did not get a SACK for at least a MSS and
9887 			 * had to move at all, or if we moved more than our
9888 			 * threshold, it counts against the "extra" move.
9889 			 */
9890 			rack->r_ctl.sack_moved_extra += moved_two;
9891 			counter_u64_add(rack_move_some, 1);
9892 		} else {
9893 			/*
9894 			 * else we did not have to move
9895 			 * any more than we would expect.
9896 			 */
9897 			rack->r_ctl.sack_noextra_move++;
9898 			counter_u64_add(rack_move_none, 1);
9899 		}
9900 		if (moved_two && (acked < ctf_fixed_maxseg(rack->rc_tp))) {
9901 			/*
9902 			 * If the SACK was not a full MSS then
9903 			 * we add to sack_count the number of
9904 			 * MSS's (or possibly more than
9905 			 * a MSS if its a TSO send) we had to skip by.
9906 			 */
9907 			rack->r_ctl.sack_count += moved_two;
9908 			counter_u64_add(rack_sack_total, moved_two);
9909 		}
9910 		/*
9911 		 * Now we need to setup for the next
9912 		 * round. First we make sure we won't
9913 		 * exceed the size of our uint32_t on
9914 		 * the various counts, and then clear out
9915 		 * moved_two.
9916 		 */
9917 		if ((rack->r_ctl.sack_moved_extra > 0xfff00000) ||
9918 		    (rack->r_ctl.sack_noextra_move > 0xfff00000)) {
9919 			rack->r_ctl.sack_moved_extra /= 2;
9920 			rack->r_ctl.sack_noextra_move /= 2;
9921 		}
9922 		if (rack->r_ctl.sack_count > 0xfff00000) {
9923 			rack->r_ctl.ack_count /= 2;
9924 			rack->r_ctl.sack_count /= 2;
9925 		}
9926 		moved_two = 0;
9927 	}
9928 out_with_totals:
9929 	if (num_sack_blks > 1) {
9930 		/*
9931 		 * You get an extra stroke if
9932 		 * you have more than one sack-blk, this
9933 		 * could be where we are skipping forward
9934 		 * and the sack-filter is still working, or
9935 		 * it could be an attacker constantly
9936 		 * moving us.
9937 		 */
9938 		rack->r_ctl.sack_moved_extra++;
9939 		counter_u64_add(rack_move_some, 1);
9940 	}
9941 out:
9942 #ifdef NETFLIX_EXP_DETECTION
9943 	rack_do_detection(tp, rack, BYTES_THIS_ACK(tp, th), ctf_fixed_maxseg(rack->rc_tp));
9944 #endif
9945 	if (changed) {
9946 		/* Something changed cancel the rack timer */
9947 		rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
9948 	}
9949 	tsused = tcp_get_usecs(NULL);
9950 	rsm = tcp_rack_output(tp, rack, tsused);
9951 	if ((!IN_FASTRECOVERY(tp->t_flags)) &&
9952 	    rsm) {
9953 		/* Enter recovery */
9954 		rack->r_ctl.rc_rsm_start = rsm->r_start;
9955 		rack->r_ctl.rc_cwnd_at = tp->snd_cwnd;
9956 		rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh;
9957 		entered_recovery = 1;
9958 		rack_cong_signal(tp, CC_NDUPACK, tp->snd_una);
9959 		/*
9960 		 * When we enter recovery we need to assure we send
9961 		 * one packet.
9962 		 */
9963 		if (rack->rack_no_prr == 0) {
9964 			rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
9965 			rack_log_to_prr(rack, 8, 0);
9966 		}
9967 		rack->r_timer_override = 1;
9968 		rack->r_early = 0;
9969 		rack->r_ctl.rc_agg_early = 0;
9970 	} else if (IN_FASTRECOVERY(tp->t_flags) &&
9971 		   rsm &&
9972 		   (rack->r_rr_config == 3)) {
9973 		/*
9974 		 * Assure we can output and we get no
9975 		 * remembered pace time except the retransmit.
9976 		 */
9977 		rack->r_timer_override = 1;
9978 		rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
9979 		rack->r_ctl.rc_resend = rsm;
9980 	}
9981 	if (IN_FASTRECOVERY(tp->t_flags) &&
9982 	    (rack->rack_no_prr == 0) &&
9983 	    (entered_recovery == 0)) {
9984 		rack_update_prr(tp, rack, changed, th_ack);
9985 		if ((rsm && (rack->r_ctl.rc_prr_sndcnt >= ctf_fixed_maxseg(tp)) &&
9986 		     ((tcp_in_hpts(rack->rc_inp) == 0) &&
9987 		      ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0)))) {
9988 			/*
9989 			 * If you are pacing output you don't want
9990 			 * to override.
9991 			 */
9992 			rack->r_early = 0;
9993 			rack->r_ctl.rc_agg_early = 0;
9994 			rack->r_timer_override = 1;
9995 		}
9996 	}
9997 }
9998 
9999 static void
10000 rack_strike_dupack(struct tcp_rack *rack)
10001 {
10002 	struct rack_sendmap *rsm;
10003 
10004 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
10005 	while (rsm && (rsm->r_dupack >= DUP_ACK_THRESHOLD)) {
10006 		rsm = TAILQ_NEXT(rsm, r_tnext);
10007 	}
10008 	if (rsm && (rsm->r_dupack < 0xff)) {
10009 		rsm->r_dupack++;
10010 		if (rsm->r_dupack >= DUP_ACK_THRESHOLD) {
10011 			struct timeval tv;
10012 			uint32_t cts;
10013 			/*
10014 			 * Here we see if we need to retransmit. For
10015 			 * a SACK type connection if enough time has passed
10016 			 * we will get a return of the rsm. For a non-sack
10017 			 * connection we will get the rsm returned if the
10018 			 * dupack value is 3 or more.
10019 			 */
10020 			cts = tcp_get_usecs(&tv);
10021 			rack->r_ctl.rc_resend = tcp_rack_output(rack->rc_tp, rack, cts);
10022 			if (rack->r_ctl.rc_resend != NULL) {
10023 				if (!IN_FASTRECOVERY(rack->rc_tp->t_flags)) {
10024 					rack_cong_signal(rack->rc_tp, CC_NDUPACK,
10025 							 rack->rc_tp->snd_una);
10026 				}
10027 				rack->r_wanted_output = 1;
10028 				rack->r_timer_override = 1;
10029 				rack_log_retran_reason(rack, rsm, __LINE__, 1, 3);
10030 			}
10031 		} else {
10032 			rack_log_retran_reason(rack, rsm, __LINE__, 0, 3);
10033 		}
10034 	}
10035 }
10036 
10037 static void
10038 rack_check_bottom_drag(struct tcpcb *tp,
10039 		       struct tcp_rack *rack,
10040 		       struct socket *so, int32_t acked)
10041 {
10042 	uint32_t segsiz, minseg;
10043 
10044 	segsiz = ctf_fixed_maxseg(tp);
10045 	minseg = segsiz;
10046 
10047 	if (tp->snd_max == tp->snd_una) {
10048 		/*
10049 		 * We are doing dynamic pacing and we are way
10050 		 * under. Basically everything got acked while
10051 		 * we were still waiting on the pacer to expire.
10052 		 *
10053 		 * This means we need to boost the b/w in
10054 		 * addition to any earlier boosting of
10055 		 * the multipler.
10056 		 */
10057 		rack->rc_dragged_bottom = 1;
10058 		rack_validate_multipliers_at_or_above100(rack);
10059 		/*
10060 		 * Lets use the segment bytes acked plus
10061 		 * the lowest RTT seen as the basis to
10062 		 * form a b/w estimate. This will be off
10063 		 * due to the fact that the true estimate
10064 		 * should be around 1/2 the time of the RTT
10065 		 * but we can settle for that.
10066 		 */
10067 		if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_VALID) &&
10068 		    acked) {
10069 			uint64_t bw, calc_bw, rtt;
10070 
10071 			rtt = rack->r_ctl.rack_rs.rs_us_rtt;
10072 			if (rtt == 0) {
10073 				/* no us sample is there a ms one? */
10074 				if (rack->r_ctl.rack_rs.rs_rtt_lowest) {
10075 					rtt = rack->r_ctl.rack_rs.rs_rtt_lowest;
10076 				} else {
10077 					goto no_measurement;
10078 				}
10079 			}
10080 			bw = acked;
10081 			calc_bw = bw * 1000000;
10082 			calc_bw /= rtt;
10083 			if (rack->r_ctl.last_max_bw &&
10084 			    (rack->r_ctl.last_max_bw < calc_bw)) {
10085 				/*
10086 				 * If we have a last calculated max bw
10087 				 * enforce it.
10088 				 */
10089 				calc_bw = rack->r_ctl.last_max_bw;
10090 			}
10091 			/* now plop it in */
10092 			if (rack->rc_gp_filled == 0) {
10093 				if (calc_bw > ONE_POINT_TWO_MEG) {
10094 					/*
10095 					 * If we have no measurement
10096 					 * don't let us set in more than
10097 					 * 1.2Mbps. If we are still too
10098 					 * low after pacing with this we
10099 					 * will hopefully have a max b/w
10100 					 * available to sanity check things.
10101 					 */
10102 					calc_bw = ONE_POINT_TWO_MEG;
10103 				}
10104 				rack->r_ctl.rc_rtt_diff = 0;
10105 				rack->r_ctl.gp_bw = calc_bw;
10106 				rack->rc_gp_filled = 1;
10107 				if (rack->r_ctl.num_measurements < RACK_REQ_AVG)
10108 					rack->r_ctl.num_measurements = RACK_REQ_AVG;
10109 				rack_set_pace_segments(rack->rc_tp, rack, __LINE__, NULL);
10110 			} else if (calc_bw > rack->r_ctl.gp_bw) {
10111 				rack->r_ctl.rc_rtt_diff = 0;
10112 				if (rack->r_ctl.num_measurements < RACK_REQ_AVG)
10113 					rack->r_ctl.num_measurements = RACK_REQ_AVG;
10114 				rack->r_ctl.gp_bw = calc_bw;
10115 				rack_set_pace_segments(rack->rc_tp, rack, __LINE__, NULL);
10116 			} else
10117 				rack_increase_bw_mul(rack, -1, 0, 0, 1);
10118 			if ((rack->gp_ready == 0) &&
10119 			    (rack->r_ctl.num_measurements >= rack->r_ctl.req_measurements)) {
10120 				/* We have enough measurements now */
10121 				rack->gp_ready = 1;
10122 				rack_set_cc_pacing(rack);
10123 				if (rack->defer_options)
10124 					rack_apply_deferred_options(rack);
10125 			}
10126 			/*
10127 			 * For acks over 1mss we do a extra boost to simulate
10128 			 * where we would get 2 acks (we want 110 for the mul).
10129 			 */
10130 			if (acked > segsiz)
10131 				rack_increase_bw_mul(rack, -1, 0, 0, 1);
10132 		} else {
10133 			/*
10134 			 * zero rtt possibly?, settle for just an old increase.
10135 			 */
10136 no_measurement:
10137 			rack_increase_bw_mul(rack, -1, 0, 0, 1);
10138 		}
10139 	} else if ((IN_FASTRECOVERY(tp->t_flags) == 0) &&
10140 		   (sbavail(&so->so_snd) > max((segsiz * (4 + rack_req_segs)),
10141 					       minseg)) &&
10142 		   (rack->r_ctl.cwnd_to_use > max((segsiz * (rack_req_segs + 2)), minseg)) &&
10143 		   (tp->snd_wnd > max((segsiz * (rack_req_segs + 2)), minseg)) &&
10144 		   (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) <=
10145 		    (segsiz * rack_req_segs))) {
10146 		/*
10147 		 * We are doing dynamic GP pacing and
10148 		 * we have everything except 1MSS or less
10149 		 * bytes left out. We are still pacing away.
10150 		 * And there is data that could be sent, This
10151 		 * means we are inserting delayed ack time in
10152 		 * our measurements because we are pacing too slow.
10153 		 */
10154 		rack_validate_multipliers_at_or_above100(rack);
10155 		rack->rc_dragged_bottom = 1;
10156 		rack_increase_bw_mul(rack, -1, 0, 0, 1);
10157 	}
10158 }
10159 
10160 
10161 
10162 static void
10163 rack_gain_for_fastoutput(struct tcp_rack *rack, struct tcpcb *tp, struct socket *so, uint32_t acked_amount)
10164 {
10165 	/*
10166 	 * The fast output path is enabled and we
10167 	 * have moved the cumack forward. Lets see if
10168 	 * we can expand forward the fast path length by
10169 	 * that amount. What we would ideally like to
10170 	 * do is increase the number of bytes in the
10171 	 * fast path block (left_to_send) by the
10172 	 * acked amount. However we have to gate that
10173 	 * by two factors:
10174 	 * 1) The amount outstanding and the rwnd of the peer
10175 	 *    (i.e. we don't want to exceed the rwnd of the peer).
10176 	 *    <and>
10177 	 * 2) The amount of data left in the socket buffer (i.e.
10178 	 *    we can't send beyond what is in the buffer).
10179 	 *
10180 	 * Note that this does not take into account any increase
10181 	 * in the cwnd. We will only extend the fast path by
10182 	 * what was acked.
10183 	 */
10184 	uint32_t new_total, gating_val;
10185 
10186 	new_total = acked_amount + rack->r_ctl.fsb.left_to_send;
10187 	gating_val = min((sbavail(&so->so_snd) - (tp->snd_max - tp->snd_una)),
10188 			 (tp->snd_wnd - (tp->snd_max - tp->snd_una)));
10189 	if (new_total <= gating_val) {
10190 		/* We can increase left_to_send by the acked amount */
10191 		counter_u64_add(rack_extended_rfo, 1);
10192 		rack->r_ctl.fsb.left_to_send = new_total;
10193 		KASSERT((rack->r_ctl.fsb.left_to_send <= (sbavail(&rack->rc_inp->inp_socket->so_snd) - (tp->snd_max - tp->snd_una))),
10194 			("rack:%p left_to_send:%u sbavail:%u out:%u",
10195 			 rack, rack->r_ctl.fsb.left_to_send,
10196 			 sbavail(&rack->rc_inp->inp_socket->so_snd),
10197 			 (tp->snd_max - tp->snd_una)));
10198 
10199 	}
10200 }
10201 
10202 static void
10203 rack_adjust_sendmap(struct tcp_rack *rack, struct sockbuf *sb, tcp_seq snd_una)
10204 {
10205 	/*
10206 	 * Here any sendmap entry that points to the
10207 	 * beginning mbuf must be adjusted to the correct
10208 	 * offset. This must be called with:
10209 	 * 1) The socket buffer locked
10210 	 * 2) snd_una adjusted to its new postion.
10211 	 *
10212 	 * Note that (2) implies rack_ack_received has also
10213 	 * been called.
10214 	 *
10215 	 * We grab the first mbuf in the socket buffer and
10216 	 * then go through the front of the sendmap, recalculating
10217 	 * the stored offset for any sendmap entry that has
10218 	 * that mbuf. We must use the sb functions to do this
10219 	 * since its possible an add was done has well as
10220 	 * the subtraction we may have just completed. This should
10221 	 * not be a penalty though, since we just referenced the sb
10222 	 * to go in and trim off the mbufs that we freed (of course
10223 	 * there will be a penalty for the sendmap references though).
10224 	 */
10225 	struct mbuf *m;
10226 	struct rack_sendmap *rsm;
10227 
10228 	SOCKBUF_LOCK_ASSERT(sb);
10229 	m = sb->sb_mb;
10230 	rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
10231 	if ((rsm == NULL) || (m == NULL)) {
10232 		/* Nothing outstanding */
10233 		return;
10234 	}
10235 	while (rsm->m && (rsm->m == m)) {
10236 		/* one to adjust */
10237 #ifdef INVARIANTS
10238 		struct mbuf *tm;
10239 		uint32_t soff;
10240 
10241 		tm = sbsndmbuf(sb, (rsm->r_start - snd_una), &soff);
10242 		if (rsm->orig_m_len != m->m_len) {
10243 			rack_adjust_orig_mlen(rsm);
10244 		}
10245 		if (rsm->soff != soff) {
10246 			/*
10247 			 * This is not a fatal error, we anticipate it
10248 			 * might happen (the else code), so we count it here
10249 			 * so that under invariant we can see that it really
10250 			 * does happen.
10251 			 */
10252 			counter_u64_add(rack_adjust_map_bw, 1);
10253 		}
10254 		rsm->m = tm;
10255 		rsm->soff = soff;
10256 		if (tm)
10257 			rsm->orig_m_len = rsm->m->m_len;
10258 		else
10259 			rsm->orig_m_len = 0;
10260 #else
10261 		rsm->m = sbsndmbuf(sb, (rsm->r_start - snd_una), &rsm->soff);
10262 		if (rsm->m)
10263 			rsm->orig_m_len = rsm->m->m_len;
10264 		else
10265 			rsm->orig_m_len = 0;
10266 #endif
10267 		rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree,
10268 			      rsm);
10269 		if (rsm == NULL)
10270 			break;
10271 	}
10272 }
10273 
10274 /*
10275  * Return value of 1, we do not need to call rack_process_data().
10276  * return value of 0, rack_process_data can be called.
10277  * For ret_val if its 0 the TCP is locked, if its non-zero
10278  * its unlocked and probably unsafe to touch the TCB.
10279  */
10280 static int
10281 rack_process_ack(struct mbuf *m, struct tcphdr *th, struct socket *so,
10282     struct tcpcb *tp, struct tcpopt *to,
10283     uint32_t tiwin, int32_t tlen,
10284     int32_t * ofia, int32_t thflags, int32_t *ret_val)
10285 {
10286 	int32_t ourfinisacked = 0;
10287 	int32_t nsegs, acked_amount;
10288 	int32_t acked;
10289 	struct mbuf *mfree;
10290 	struct tcp_rack *rack;
10291 	int32_t under_pacing = 0;
10292 	int32_t recovery = 0;
10293 
10294 	rack = (struct tcp_rack *)tp->t_fb_ptr;
10295 	if (SEQ_GT(th->th_ack, tp->snd_max)) {
10296 		__ctf_do_dropafterack(m, tp, th, thflags, tlen, ret_val,
10297 				      &rack->r_ctl.challenge_ack_ts,
10298 				      &rack->r_ctl.challenge_ack_cnt);
10299 		rack->r_wanted_output = 1;
10300 		return (1);
10301 	}
10302 	if (rack->gp_ready &&
10303 	    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
10304 		under_pacing = 1;
10305 	}
10306 	if (SEQ_GEQ(th->th_ack, tp->snd_una) || to->to_nsacks) {
10307 		int in_rec, dup_ack_struck = 0;
10308 
10309 		in_rec = IN_FASTRECOVERY(tp->t_flags);
10310 		if (rack->rc_in_persist) {
10311 			tp->t_rxtshift = 0;
10312 			RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
10313 				      rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
10314 		}
10315 		if ((th->th_ack == tp->snd_una) &&
10316 		    (tiwin == tp->snd_wnd) &&
10317 		    ((to->to_flags & TOF_SACK) == 0)) {
10318 			rack_strike_dupack(rack);
10319 			dup_ack_struck = 1;
10320 		}
10321 		rack_log_ack(tp, to, th, ((in_rec == 0) && IN_FASTRECOVERY(tp->t_flags)), dup_ack_struck);
10322 	}
10323 	if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
10324 		/*
10325 		 * Old ack, behind (or duplicate to) the last one rcv'd
10326 		 * Note: We mark reordering is occuring if its
10327 		 * less than and we have not closed our window.
10328 		 */
10329 		if (SEQ_LT(th->th_ack, tp->snd_una) && (sbspace(&so->so_rcv) > ctf_fixed_maxseg(tp))) {
10330 			counter_u64_add(rack_reorder_seen, 1);
10331 			rack->r_ctl.rc_reorder_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
10332 		}
10333 		return (0);
10334 	}
10335 	/*
10336 	 * If we reach this point, ACK is not a duplicate, i.e., it ACKs
10337 	 * something we sent.
10338 	 */
10339 	if (tp->t_flags & TF_NEEDSYN) {
10340 		/*
10341 		 * T/TCP: Connection was half-synchronized, and our SYN has
10342 		 * been ACK'd (so connection is now fully synchronized).  Go
10343 		 * to non-starred state, increment snd_una for ACK of SYN,
10344 		 * and check if we can do window scaling.
10345 		 */
10346 		tp->t_flags &= ~TF_NEEDSYN;
10347 		tp->snd_una++;
10348 		/* Do window scaling? */
10349 		if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
10350 		    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
10351 			tp->rcv_scale = tp->request_r_scale;
10352 			/* Send window already scaled. */
10353 		}
10354 	}
10355 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
10356 	INP_WLOCK_ASSERT(tp->t_inpcb);
10357 
10358 	acked = BYTES_THIS_ACK(tp, th);
10359 	if (acked) {
10360 		/*
10361 		 * Any time we move the cum-ack forward clear
10362 		 * keep-alive tied probe-not-answered. The
10363 		 * persists clears its own on entry.
10364 		 */
10365 		rack->probe_not_answered = 0;
10366 	}
10367 	KMOD_TCPSTAT_ADD(tcps_rcvackpack, nsegs);
10368 	KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
10369 	/*
10370 	 * If we just performed our first retransmit, and the ACK arrives
10371 	 * within our recovery window, then it was a mistake to do the
10372 	 * retransmit in the first place.  Recover our original cwnd and
10373 	 * ssthresh, and proceed to transmit where we left off.
10374 	 */
10375 	if ((tp->t_flags & TF_PREVVALID) &&
10376 	    ((tp->t_flags & TF_RCVD_TSTMP) == 0)) {
10377 		tp->t_flags &= ~TF_PREVVALID;
10378 		if (tp->t_rxtshift == 1 &&
10379 		    (int)(ticks - tp->t_badrxtwin) < 0)
10380 			rack_cong_signal(tp, CC_RTO_ERR, th->th_ack);
10381 	}
10382 	if (acked) {
10383 		/* assure we are not backed off */
10384 		tp->t_rxtshift = 0;
10385 		RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
10386 			      rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
10387 		rack->rc_tlp_in_progress = 0;
10388 		rack->r_ctl.rc_tlp_cnt_out = 0;
10389 		/*
10390 		 * If it is the RXT timer we want to
10391 		 * stop it, so we can restart a TLP.
10392 		 */
10393 		if (rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT)
10394 			rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
10395 #ifdef NETFLIX_HTTP_LOGGING
10396 		tcp_http_check_for_comp(rack->rc_tp, th->th_ack);
10397 #endif
10398 	}
10399 	/*
10400 	 * If we have a timestamp reply, update smoothed round trip time. If
10401 	 * no timestamp is present but transmit timer is running and timed
10402 	 * sequence number was acked, update smoothed round trip time. Since
10403 	 * we now have an rtt measurement, cancel the timer backoff (cf.,
10404 	 * Phil Karn's retransmit alg.). Recompute the initial retransmit
10405 	 * timer.
10406 	 *
10407 	 * Some boxes send broken timestamp replies during the SYN+ACK
10408 	 * phase, ignore timestamps of 0 or we could calculate a huge RTT
10409 	 * and blow up the retransmit timer.
10410 	 */
10411 	/*
10412 	 * If all outstanding data is acked, stop retransmit timer and
10413 	 * remember to restart (more output or persist). If there is more
10414 	 * data to be acked, restart retransmit timer, using current
10415 	 * (possibly backed-off) value.
10416 	 */
10417 	if (acked == 0) {
10418 		if (ofia)
10419 			*ofia = ourfinisacked;
10420 		return (0);
10421 	}
10422 	if (IN_RECOVERY(tp->t_flags)) {
10423 		if (SEQ_LT(th->th_ack, tp->snd_recover) &&
10424 		    (SEQ_LT(th->th_ack, tp->snd_max))) {
10425 			tcp_rack_partialack(tp);
10426 		} else {
10427 			rack_post_recovery(tp, th->th_ack);
10428 			recovery = 1;
10429 		}
10430 	}
10431 	/*
10432 	 * Let the congestion control algorithm update congestion control
10433 	 * related information. This typically means increasing the
10434 	 * congestion window.
10435 	 */
10436 	rack_ack_received(tp, rack, th->th_ack, nsegs, CC_ACK, recovery);
10437 	SOCKBUF_LOCK(&so->so_snd);
10438 	acked_amount = min(acked, (int)sbavail(&so->so_snd));
10439 	tp->snd_wnd -= acked_amount;
10440 	mfree = sbcut_locked(&so->so_snd, acked_amount);
10441 	if ((sbused(&so->so_snd) == 0) &&
10442 	    (acked > acked_amount) &&
10443 	    (tp->t_state >= TCPS_FIN_WAIT_1) &&
10444 	    (tp->t_flags & TF_SENTFIN)) {
10445 		/*
10446 		 * We must be sure our fin
10447 		 * was sent and acked (we can be
10448 		 * in FIN_WAIT_1 without having
10449 		 * sent the fin).
10450 		 */
10451 		ourfinisacked = 1;
10452 	}
10453 	tp->snd_una = th->th_ack;
10454 	if (acked_amount && sbavail(&so->so_snd))
10455 		rack_adjust_sendmap(rack, &so->so_snd, tp->snd_una);
10456 	rack_log_wakeup(tp,rack, &so->so_snd, acked, 2);
10457 	/* NB: sowwakeup_locked() does an implicit unlock. */
10458 	sowwakeup_locked(so);
10459 	m_freem(mfree);
10460 	if (SEQ_GT(tp->snd_una, tp->snd_recover))
10461 		tp->snd_recover = tp->snd_una;
10462 
10463 	if (SEQ_LT(tp->snd_nxt, tp->snd_una)) {
10464 		tp->snd_nxt = tp->snd_una;
10465 	}
10466 	if (under_pacing &&
10467 	    (rack->use_fixed_rate == 0) &&
10468 	    (rack->in_probe_rtt == 0) &&
10469 	    rack->rc_gp_dyn_mul &&
10470 	    rack->rc_always_pace) {
10471 		/* Check if we are dragging bottom */
10472 		rack_check_bottom_drag(tp, rack, so, acked);
10473 	}
10474 	if (tp->snd_una == tp->snd_max) {
10475 		/* Nothing left outstanding */
10476 		tp->t_flags &= ~TF_PREVVALID;
10477 		rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
10478 		rack->r_ctl.retran_during_recovery = 0;
10479 		rack->r_ctl.dsack_byte_cnt = 0;
10480 		if (rack->r_ctl.rc_went_idle_time == 0)
10481 			rack->r_ctl.rc_went_idle_time = 1;
10482 		rack_log_progress_event(rack, tp, 0, PROGRESS_CLEAR, __LINE__);
10483 		if (sbavail(&tp->t_inpcb->inp_socket->so_snd) == 0)
10484 			tp->t_acktime = 0;
10485 		rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
10486 		/* Set need output so persist might get set */
10487 		rack->r_wanted_output = 1;
10488 		sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
10489 		if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
10490 		    (sbavail(&so->so_snd) == 0) &&
10491 		    (tp->t_flags2 & TF2_DROP_AF_DATA)) {
10492 			/*
10493 			 * The socket was gone and the
10494 			 * peer sent data (now or in the past), time to
10495 			 * reset him.
10496 			 */
10497 			*ret_val = 1;
10498 			/* tcp_close will kill the inp pre-log the Reset */
10499 			tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
10500 			tp = tcp_close(tp);
10501 			ctf_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, tlen);
10502 			return (1);
10503 		}
10504 	}
10505 	if (ofia)
10506 		*ofia = ourfinisacked;
10507 	return (0);
10508 }
10509 
10510 static void
10511 rack_collapsed_window(struct tcp_rack *rack)
10512 {
10513 	/*
10514 	 * Now we must walk the
10515 	 * send map and divide the
10516 	 * ones left stranded. These
10517 	 * guys can't cause us to abort
10518 	 * the connection and are really
10519 	 * "unsent". However if a buggy
10520 	 * client actually did keep some
10521 	 * of the data i.e. collapsed the win
10522 	 * and refused to ack and then opened
10523 	 * the win and acked that data. We would
10524 	 * get into an ack war, the simplier
10525 	 * method then of just pretending we
10526 	 * did not send those segments something
10527 	 * won't work.
10528 	 */
10529 	struct rack_sendmap *rsm, *nrsm, fe, *insret;
10530 	tcp_seq max_seq;
10531 
10532 	max_seq = rack->rc_tp->snd_una + rack->rc_tp->snd_wnd;
10533 	memset(&fe, 0, sizeof(fe));
10534 	fe.r_start = max_seq;
10535 	/* Find the first seq past or at maxseq */
10536 	rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
10537 	if (rsm == NULL) {
10538 		/* Nothing to do strange */
10539 		rack->rc_has_collapsed = 0;
10540 		return;
10541 	}
10542 	/*
10543 	 * Now do we need to split at
10544 	 * the collapse point?
10545 	 */
10546 	if (SEQ_GT(max_seq, rsm->r_start)) {
10547 		nrsm = rack_alloc_limit(rack, RACK_LIMIT_TYPE_SPLIT);
10548 		if (nrsm == NULL) {
10549 			/* We can't get a rsm, mark all? */
10550 			nrsm = rsm;
10551 			goto no_split;
10552 		}
10553 		/* Clone it */
10554 		rack_clone_rsm(rack, nrsm, rsm, max_seq);
10555 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
10556 #ifdef INVARIANTS
10557 		if (insret != NULL) {
10558 			panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
10559 			      nrsm, insret, rack, rsm);
10560 		}
10561 #endif
10562 		rack_log_map_chg(rack->rc_tp, rack, NULL, rsm, nrsm, MAP_SPLIT, max_seq, __LINE__);
10563 		if (rsm->r_in_tmap) {
10564 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
10565 			nrsm->r_in_tmap = 1;
10566 		}
10567 		/*
10568 		 * Set in the new RSM as the
10569 		 * collapsed starting point
10570 		 */
10571 		rsm = nrsm;
10572 	}
10573 no_split:
10574 	counter_u64_add(rack_collapsed_win, 1);
10575 	RB_FOREACH_FROM(nrsm, rack_rb_tree_head, rsm) {
10576 		nrsm->r_flags |= RACK_RWND_COLLAPSED;
10577 	}
10578 	rack->rc_has_collapsed = 1;
10579 }
10580 
10581 static void
10582 rack_un_collapse_window(struct tcp_rack *rack)
10583 {
10584 	struct rack_sendmap *rsm;
10585 
10586 	RB_FOREACH_REVERSE(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
10587 		if (rsm->r_flags & RACK_RWND_COLLAPSED)
10588 			rsm->r_flags &= ~RACK_RWND_COLLAPSED;
10589 		else
10590 			break;
10591 	}
10592 	rack->rc_has_collapsed = 0;
10593 }
10594 
10595 static void
10596 rack_handle_delayed_ack(struct tcpcb *tp, struct tcp_rack *rack,
10597 			int32_t tlen, int32_t tfo_syn)
10598 {
10599 	if (DELAY_ACK(tp, tlen) || tfo_syn) {
10600 		if (rack->rc_dack_mode &&
10601 		    (tlen > 500) &&
10602 		    (rack->rc_dack_toggle == 1)) {
10603 			goto no_delayed_ack;
10604 		}
10605 		rack_timer_cancel(tp, rack,
10606 				  rack->r_ctl.rc_rcvtime, __LINE__);
10607 		tp->t_flags |= TF_DELACK;
10608 	} else {
10609 no_delayed_ack:
10610 		rack->r_wanted_output = 1;
10611 		tp->t_flags |= TF_ACKNOW;
10612 		if (rack->rc_dack_mode) {
10613 			if (tp->t_flags & TF_DELACK)
10614 				rack->rc_dack_toggle = 1;
10615 			else
10616 				rack->rc_dack_toggle = 0;
10617 		}
10618 	}
10619 }
10620 
10621 static void
10622 rack_validate_fo_sendwin_up(struct tcpcb *tp, struct tcp_rack *rack)
10623 {
10624 	/*
10625 	 * If fast output is in progress, lets validate that
10626 	 * the new window did not shrink on us and make it
10627 	 * so fast output should end.
10628 	 */
10629 	if (rack->r_fast_output) {
10630 		uint32_t out;
10631 
10632 		/*
10633 		 * Calculate what we will send if left as is
10634 		 * and compare that to our send window.
10635 		 */
10636 		out = ctf_outstanding(tp);
10637 		if ((out + rack->r_ctl.fsb.left_to_send) > tp->snd_wnd) {
10638 			/* ok we have an issue */
10639 			if (out >= tp->snd_wnd) {
10640 				/* Turn off fast output the window is met or collapsed */
10641 				rack->r_fast_output = 0;
10642 			} else {
10643 				/* we have some room left */
10644 				rack->r_ctl.fsb.left_to_send = tp->snd_wnd - out;
10645 				if (rack->r_ctl.fsb.left_to_send < ctf_fixed_maxseg(tp)) {
10646 					/* If not at least 1 full segment never mind */
10647 					rack->r_fast_output = 0;
10648 				}
10649 			}
10650 		}
10651 	}
10652 }
10653 
10654 
10655 /*
10656  * Return value of 1, the TCB is unlocked and most
10657  * likely gone, return value of 0, the TCP is still
10658  * locked.
10659  */
10660 static int
10661 rack_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so,
10662     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
10663     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
10664 {
10665 	/*
10666 	 * Update window information. Don't look at window if no ACK: TAC's
10667 	 * send garbage on first SYN.
10668 	 */
10669 	int32_t nsegs;
10670 	int32_t tfo_syn;
10671 	struct tcp_rack *rack;
10672 
10673 	rack = (struct tcp_rack *)tp->t_fb_ptr;
10674 	INP_WLOCK_ASSERT(tp->t_inpcb);
10675 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
10676 	if ((thflags & TH_ACK) &&
10677 	    (SEQ_LT(tp->snd_wl1, th->th_seq) ||
10678 	    (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) ||
10679 	    (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) {
10680 		/* keep track of pure window updates */
10681 		if (tlen == 0 &&
10682 		    tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd)
10683 			KMOD_TCPSTAT_INC(tcps_rcvwinupd);
10684 		tp->snd_wnd = tiwin;
10685 		rack_validate_fo_sendwin_up(tp, rack);
10686 		tp->snd_wl1 = th->th_seq;
10687 		tp->snd_wl2 = th->th_ack;
10688 		if (tp->snd_wnd > tp->max_sndwnd)
10689 			tp->max_sndwnd = tp->snd_wnd;
10690 		rack->r_wanted_output = 1;
10691 	} else if (thflags & TH_ACK) {
10692 		if ((tp->snd_wl2 == th->th_ack) && (tiwin < tp->snd_wnd)) {
10693 			tp->snd_wnd = tiwin;
10694 			rack_validate_fo_sendwin_up(tp, rack);
10695 			tp->snd_wl1 = th->th_seq;
10696 			tp->snd_wl2 = th->th_ack;
10697 		}
10698 	}
10699 	if (tp->snd_wnd < ctf_outstanding(tp))
10700 		/* The peer collapsed the window */
10701 		rack_collapsed_window(rack);
10702 	else if (rack->rc_has_collapsed)
10703 		rack_un_collapse_window(rack);
10704 	/* Was persist timer active and now we have window space? */
10705 	if ((rack->rc_in_persist != 0) &&
10706 	    (tp->snd_wnd >= min((rack->r_ctl.rc_high_rwnd/2),
10707 				rack->r_ctl.rc_pace_min_segs))) {
10708 		rack_exit_persist(tp, rack, rack->r_ctl.rc_rcvtime);
10709 		tp->snd_nxt = tp->snd_max;
10710 		/* Make sure we output to start the timer */
10711 		rack->r_wanted_output = 1;
10712 	}
10713 	/* Do we enter persists? */
10714 	if ((rack->rc_in_persist == 0) &&
10715 	    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), rack->r_ctl.rc_pace_min_segs)) &&
10716 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
10717 	    (tp->snd_max == tp->snd_una) &&
10718 	    sbavail(&tp->t_inpcb->inp_socket->so_snd) &&
10719 	    (sbavail(&tp->t_inpcb->inp_socket->so_snd) > tp->snd_wnd)) {
10720 		/*
10721 		 * Here the rwnd is less than
10722 		 * the pacing size, we are established,
10723 		 * nothing is outstanding, and there is
10724 		 * data to send. Enter persists.
10725 		 */
10726 		rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
10727 	}
10728 	if (tp->t_flags2 & TF2_DROP_AF_DATA) {
10729 		m_freem(m);
10730 		return (0);
10731 	}
10732 	/*
10733 	 * don't process the URG bit, ignore them drag
10734 	 * along the up.
10735 	 */
10736 	tp->rcv_up = tp->rcv_nxt;
10737 	INP_WLOCK_ASSERT(tp->t_inpcb);
10738 
10739 	/*
10740 	 * Process the segment text, merging it into the TCP sequencing
10741 	 * queue, and arranging for acknowledgment of receipt if necessary.
10742 	 * This process logically involves adjusting tp->rcv_wnd as data is
10743 	 * presented to the user (this happens in tcp_usrreq.c, case
10744 	 * PRU_RCVD).  If a FIN has already been received on this connection
10745 	 * then we just ignore the text.
10746 	 */
10747 	tfo_syn = ((tp->t_state == TCPS_SYN_RECEIVED) &&
10748 		   IS_FASTOPEN(tp->t_flags));
10749 	if ((tlen || (thflags & TH_FIN) || (tfo_syn && tlen > 0)) &&
10750 	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
10751 		tcp_seq save_start = th->th_seq;
10752 		tcp_seq save_rnxt  = tp->rcv_nxt;
10753 		int     save_tlen  = tlen;
10754 
10755 		m_adj(m, drop_hdrlen);	/* delayed header drop */
10756 		/*
10757 		 * Insert segment which includes th into TCP reassembly
10758 		 * queue with control block tp.  Set thflags to whether
10759 		 * reassembly now includes a segment with FIN.  This handles
10760 		 * the common case inline (segment is the next to be
10761 		 * received on an established connection, and the queue is
10762 		 * empty), avoiding linkage into and removal from the queue
10763 		 * and repetition of various conversions. Set DELACK for
10764 		 * segments received in order, but ack immediately when
10765 		 * segments are out of order (so fast retransmit can work).
10766 		 */
10767 		if (th->th_seq == tp->rcv_nxt &&
10768 		    SEGQ_EMPTY(tp) &&
10769 		    (TCPS_HAVEESTABLISHED(tp->t_state) ||
10770 		    tfo_syn)) {
10771 #ifdef NETFLIX_SB_LIMITS
10772 			u_int mcnt, appended;
10773 
10774 			if (so->so_rcv.sb_shlim) {
10775 				mcnt = m_memcnt(m);
10776 				appended = 0;
10777 				if (counter_fo_get(so->so_rcv.sb_shlim, mcnt,
10778 				    CFO_NOSLEEP, NULL) == false) {
10779 					counter_u64_add(tcp_sb_shlim_fails, 1);
10780 					m_freem(m);
10781 					return (0);
10782 				}
10783 			}
10784 #endif
10785 			rack_handle_delayed_ack(tp, rack, tlen, tfo_syn);
10786 			tp->rcv_nxt += tlen;
10787 			if (tlen &&
10788 			    ((tp->t_flags2 & TF2_FBYTES_COMPLETE) == 0) &&
10789 			    (tp->t_fbyte_in == 0)) {
10790 				tp->t_fbyte_in = ticks;
10791 				if (tp->t_fbyte_in == 0)
10792 					tp->t_fbyte_in = 1;
10793 				if (tp->t_fbyte_out && tp->t_fbyte_in)
10794 					tp->t_flags2 |= TF2_FBYTES_COMPLETE;
10795 			}
10796 			thflags = th->th_flags & TH_FIN;
10797 			KMOD_TCPSTAT_ADD(tcps_rcvpack, nsegs);
10798 			KMOD_TCPSTAT_ADD(tcps_rcvbyte, tlen);
10799 			SOCKBUF_LOCK(&so->so_rcv);
10800 			if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
10801 				m_freem(m);
10802 			} else
10803 #ifdef NETFLIX_SB_LIMITS
10804 				appended =
10805 #endif
10806 					sbappendstream_locked(&so->so_rcv, m, 0);
10807 
10808 			rack_log_wakeup(tp,rack, &so->so_rcv, tlen, 1);
10809 			/* NB: sorwakeup_locked() does an implicit unlock. */
10810 			sorwakeup_locked(so);
10811 #ifdef NETFLIX_SB_LIMITS
10812 			if (so->so_rcv.sb_shlim && appended != mcnt)
10813 				counter_fo_release(so->so_rcv.sb_shlim,
10814 				    mcnt - appended);
10815 #endif
10816 		} else {
10817 			/*
10818 			 * XXX: Due to the header drop above "th" is
10819 			 * theoretically invalid by now.  Fortunately
10820 			 * m_adj() doesn't actually frees any mbufs when
10821 			 * trimming from the head.
10822 			 */
10823 			tcp_seq temp = save_start;
10824 
10825 			thflags = tcp_reass(tp, th, &temp, &tlen, m);
10826 			tp->t_flags |= TF_ACKNOW;
10827 			if (tp->t_flags & TF_WAKESOR) {
10828 				tp->t_flags &= ~TF_WAKESOR;
10829 				/* NB: sorwakeup_locked() does an implicit unlock. */
10830 				sorwakeup_locked(so);
10831 			}
10832 		}
10833 		if ((tp->t_flags & TF_SACK_PERMIT) &&
10834 		    (save_tlen > 0) &&
10835 		    TCPS_HAVEESTABLISHED(tp->t_state)) {
10836 			if ((tlen == 0) && (SEQ_LT(save_start, save_rnxt))) {
10837 				/*
10838 				 * DSACK actually handled in the fastpath
10839 				 * above.
10840 				 */
10841 				RACK_OPTS_INC(tcp_sack_path_1);
10842 				tcp_update_sack_list(tp, save_start,
10843 				    save_start + save_tlen);
10844 			} else if ((tlen > 0) && SEQ_GT(tp->rcv_nxt, save_rnxt)) {
10845 				if ((tp->rcv_numsacks >= 1) &&
10846 				    (tp->sackblks[0].end == save_start)) {
10847 					/*
10848 					 * Partial overlap, recorded at todrop
10849 					 * above.
10850 					 */
10851 					RACK_OPTS_INC(tcp_sack_path_2a);
10852 					tcp_update_sack_list(tp,
10853 					    tp->sackblks[0].start,
10854 					    tp->sackblks[0].end);
10855 				} else {
10856 					RACK_OPTS_INC(tcp_sack_path_2b);
10857 					tcp_update_dsack_list(tp, save_start,
10858 					    save_start + save_tlen);
10859 				}
10860 			} else if (tlen >= save_tlen) {
10861 				/* Update of sackblks. */
10862 				RACK_OPTS_INC(tcp_sack_path_3);
10863 				tcp_update_dsack_list(tp, save_start,
10864 				    save_start + save_tlen);
10865 			} else if (tlen > 0) {
10866 				RACK_OPTS_INC(tcp_sack_path_4);
10867 				tcp_update_dsack_list(tp, save_start,
10868 				    save_start + tlen);
10869 			}
10870 		}
10871 	} else {
10872 		m_freem(m);
10873 		thflags &= ~TH_FIN;
10874 	}
10875 
10876 	/*
10877 	 * If FIN is received ACK the FIN and let the user know that the
10878 	 * connection is closing.
10879 	 */
10880 	if (thflags & TH_FIN) {
10881 		if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
10882 			/* The socket upcall is handled by socantrcvmore. */
10883 			socantrcvmore(so);
10884 			/*
10885 			 * If connection is half-synchronized (ie NEEDSYN
10886 			 * flag on) then delay ACK, so it may be piggybacked
10887 			 * when SYN is sent. Otherwise, since we received a
10888 			 * FIN then no more input can be expected, send ACK
10889 			 * now.
10890 			 */
10891 			if (tp->t_flags & TF_NEEDSYN) {
10892 				rack_timer_cancel(tp, rack,
10893 				    rack->r_ctl.rc_rcvtime, __LINE__);
10894 				tp->t_flags |= TF_DELACK;
10895 			} else {
10896 				tp->t_flags |= TF_ACKNOW;
10897 			}
10898 			tp->rcv_nxt++;
10899 		}
10900 		switch (tp->t_state) {
10901 			/*
10902 			 * In SYN_RECEIVED and ESTABLISHED STATES enter the
10903 			 * CLOSE_WAIT state.
10904 			 */
10905 		case TCPS_SYN_RECEIVED:
10906 			tp->t_starttime = ticks;
10907 			/* FALLTHROUGH */
10908 		case TCPS_ESTABLISHED:
10909 			rack_timer_cancel(tp, rack,
10910 			    rack->r_ctl.rc_rcvtime, __LINE__);
10911 			tcp_state_change(tp, TCPS_CLOSE_WAIT);
10912 			break;
10913 
10914 			/*
10915 			 * If still in FIN_WAIT_1 STATE FIN has not been
10916 			 * acked so enter the CLOSING state.
10917 			 */
10918 		case TCPS_FIN_WAIT_1:
10919 			rack_timer_cancel(tp, rack,
10920 			    rack->r_ctl.rc_rcvtime, __LINE__);
10921 			tcp_state_change(tp, TCPS_CLOSING);
10922 			break;
10923 
10924 			/*
10925 			 * In FIN_WAIT_2 state enter the TIME_WAIT state,
10926 			 * starting the time-wait timer, turning off the
10927 			 * other standard timers.
10928 			 */
10929 		case TCPS_FIN_WAIT_2:
10930 			rack_timer_cancel(tp, rack,
10931 			    rack->r_ctl.rc_rcvtime, __LINE__);
10932 			tcp_twstart(tp);
10933 			return (1);
10934 		}
10935 	}
10936 	/*
10937 	 * Return any desired output.
10938 	 */
10939 	if ((tp->t_flags & TF_ACKNOW) ||
10940 	    (sbavail(&so->so_snd) > (tp->snd_max - tp->snd_una))) {
10941 		rack->r_wanted_output = 1;
10942 	}
10943 	INP_WLOCK_ASSERT(tp->t_inpcb);
10944 	return (0);
10945 }
10946 
10947 /*
10948  * Here nothing is really faster, its just that we
10949  * have broken out the fast-data path also just like
10950  * the fast-ack.
10951  */
10952 static int
10953 rack_do_fastnewdata(struct mbuf *m, struct tcphdr *th, struct socket *so,
10954     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
10955     uint32_t tiwin, int32_t nxt_pkt, uint8_t iptos)
10956 {
10957 	int32_t nsegs;
10958 	int32_t newsize = 0;	/* automatic sockbuf scaling */
10959 	struct tcp_rack *rack;
10960 #ifdef NETFLIX_SB_LIMITS
10961 	u_int mcnt, appended;
10962 #endif
10963 #ifdef TCPDEBUG
10964 	/*
10965 	 * The size of tcp_saveipgen must be the size of the max ip header,
10966 	 * now IPv6.
10967 	 */
10968 	u_char tcp_saveipgen[IP6_HDR_LEN];
10969 	struct tcphdr tcp_savetcp;
10970 	short ostate = 0;
10971 
10972 #endif
10973 	/*
10974 	 * If last ACK falls within this segment's sequence numbers, record
10975 	 * the timestamp. NOTE that the test is modified according to the
10976 	 * latest proposal of the tcplw@cray.com list (Braden 1993/04/26).
10977 	 */
10978 	if (__predict_false(th->th_seq != tp->rcv_nxt)) {
10979 		return (0);
10980 	}
10981 	if (__predict_false(tp->snd_nxt != tp->snd_max)) {
10982 		return (0);
10983 	}
10984 	if (tiwin && tiwin != tp->snd_wnd) {
10985 		return (0);
10986 	}
10987 	if (__predict_false((tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN)))) {
10988 		return (0);
10989 	}
10990 	if (__predict_false((to->to_flags & TOF_TS) &&
10991 	    (TSTMP_LT(to->to_tsval, tp->ts_recent)))) {
10992 		return (0);
10993 	}
10994 	if (__predict_false((th->th_ack != tp->snd_una))) {
10995 		return (0);
10996 	}
10997 	if (__predict_false(tlen > sbspace(&so->so_rcv))) {
10998 		return (0);
10999 	}
11000 	if ((to->to_flags & TOF_TS) != 0 &&
11001 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
11002 		tp->ts_recent_age = tcp_ts_getticks();
11003 		tp->ts_recent = to->to_tsval;
11004 	}
11005 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11006 	/*
11007 	 * This is a pure, in-sequence data packet with nothing on the
11008 	 * reassembly queue and we have enough buffer space to take it.
11009 	 */
11010 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
11011 
11012 #ifdef NETFLIX_SB_LIMITS
11013 	if (so->so_rcv.sb_shlim) {
11014 		mcnt = m_memcnt(m);
11015 		appended = 0;
11016 		if (counter_fo_get(so->so_rcv.sb_shlim, mcnt,
11017 		    CFO_NOSLEEP, NULL) == false) {
11018 			counter_u64_add(tcp_sb_shlim_fails, 1);
11019 			m_freem(m);
11020 			return (1);
11021 		}
11022 	}
11023 #endif
11024 	/* Clean receiver SACK report if present */
11025 	if (tp->rcv_numsacks)
11026 		tcp_clean_sackreport(tp);
11027 	KMOD_TCPSTAT_INC(tcps_preddat);
11028 	tp->rcv_nxt += tlen;
11029 	if (tlen &&
11030 	    ((tp->t_flags2 & TF2_FBYTES_COMPLETE) == 0) &&
11031 	    (tp->t_fbyte_in == 0)) {
11032 		tp->t_fbyte_in = ticks;
11033 		if (tp->t_fbyte_in == 0)
11034 			tp->t_fbyte_in = 1;
11035 		if (tp->t_fbyte_out && tp->t_fbyte_in)
11036 			tp->t_flags2 |= TF2_FBYTES_COMPLETE;
11037 	}
11038 	/*
11039 	 * Pull snd_wl1 up to prevent seq wrap relative to th_seq.
11040 	 */
11041 	tp->snd_wl1 = th->th_seq;
11042 	/*
11043 	 * Pull rcv_up up to prevent seq wrap relative to rcv_nxt.
11044 	 */
11045 	tp->rcv_up = tp->rcv_nxt;
11046 	KMOD_TCPSTAT_ADD(tcps_rcvpack, nsegs);
11047 	KMOD_TCPSTAT_ADD(tcps_rcvbyte, tlen);
11048 #ifdef TCPDEBUG
11049 	if (so->so_options & SO_DEBUG)
11050 		tcp_trace(TA_INPUT, ostate, tp,
11051 		    (void *)tcp_saveipgen, &tcp_savetcp, 0);
11052 #endif
11053 	newsize = tcp_autorcvbuf(m, th, so, tp, tlen);
11054 
11055 	/* Add data to socket buffer. */
11056 	SOCKBUF_LOCK(&so->so_rcv);
11057 	if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
11058 		m_freem(m);
11059 	} else {
11060 		/*
11061 		 * Set new socket buffer size. Give up when limit is
11062 		 * reached.
11063 		 */
11064 		if (newsize)
11065 			if (!sbreserve_locked(&so->so_rcv,
11066 			    newsize, so, NULL))
11067 				so->so_rcv.sb_flags &= ~SB_AUTOSIZE;
11068 		m_adj(m, drop_hdrlen);	/* delayed header drop */
11069 #ifdef NETFLIX_SB_LIMITS
11070 		appended =
11071 #endif
11072 			sbappendstream_locked(&so->so_rcv, m, 0);
11073 		ctf_calc_rwin(so, tp);
11074 	}
11075 	rack_log_wakeup(tp,rack, &so->so_rcv, tlen, 1);
11076 	/* NB: sorwakeup_locked() does an implicit unlock. */
11077 	sorwakeup_locked(so);
11078 #ifdef NETFLIX_SB_LIMITS
11079 	if (so->so_rcv.sb_shlim && mcnt != appended)
11080 		counter_fo_release(so->so_rcv.sb_shlim, mcnt - appended);
11081 #endif
11082 	rack_handle_delayed_ack(tp, rack, tlen, 0);
11083 	if (tp->snd_una == tp->snd_max)
11084 		sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
11085 	return (1);
11086 }
11087 
11088 /*
11089  * This subfunction is used to try to highly optimize the
11090  * fast path. We again allow window updates that are
11091  * in sequence to remain in the fast-path. We also add
11092  * in the __predict's to attempt to help the compiler.
11093  * Note that if we return a 0, then we can *not* process
11094  * it and the caller should push the packet into the
11095  * slow-path.
11096  */
11097 static int
11098 rack_fastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
11099     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
11100     uint32_t tiwin, int32_t nxt_pkt, uint32_t cts)
11101 {
11102 	int32_t acked;
11103 	int32_t nsegs;
11104 #ifdef TCPDEBUG
11105 	/*
11106 	 * The size of tcp_saveipgen must be the size of the max ip header,
11107 	 * now IPv6.
11108 	 */
11109 	u_char tcp_saveipgen[IP6_HDR_LEN];
11110 	struct tcphdr tcp_savetcp;
11111 	short ostate = 0;
11112 #endif
11113 	int32_t under_pacing = 0;
11114 	struct tcp_rack *rack;
11115 
11116 	if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
11117 		/* Old ack, behind (or duplicate to) the last one rcv'd */
11118 		return (0);
11119 	}
11120 	if (__predict_false(SEQ_GT(th->th_ack, tp->snd_max))) {
11121 		/* Above what we have sent? */
11122 		return (0);
11123 	}
11124 	if (__predict_false(tp->snd_nxt != tp->snd_max)) {
11125 		/* We are retransmitting */
11126 		return (0);
11127 	}
11128 	if (__predict_false(tiwin == 0)) {
11129 		/* zero window */
11130 		return (0);
11131 	}
11132 	if (__predict_false(tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN))) {
11133 		/* We need a SYN or a FIN, unlikely.. */
11134 		return (0);
11135 	}
11136 	if ((to->to_flags & TOF_TS) && __predict_false(TSTMP_LT(to->to_tsval, tp->ts_recent))) {
11137 		/* Timestamp is behind .. old ack with seq wrap? */
11138 		return (0);
11139 	}
11140 	if (__predict_false(IN_RECOVERY(tp->t_flags))) {
11141 		/* Still recovering */
11142 		return (0);
11143 	}
11144 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11145 	if (rack->r_ctl.rc_sacked) {
11146 		/* We have sack holes on our scoreboard */
11147 		return (0);
11148 	}
11149 	/* Ok if we reach here, we can process a fast-ack */
11150 	if (rack->gp_ready &&
11151 	    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
11152 		under_pacing = 1;
11153 	}
11154 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
11155 	rack_log_ack(tp, to, th, 0, 0);
11156 	/* Did the window get updated? */
11157 	if (tiwin != tp->snd_wnd) {
11158 		tp->snd_wnd = tiwin;
11159 		rack_validate_fo_sendwin_up(tp, rack);
11160 		tp->snd_wl1 = th->th_seq;
11161 		if (tp->snd_wnd > tp->max_sndwnd)
11162 			tp->max_sndwnd = tp->snd_wnd;
11163 	}
11164 	/* Do we exit persists? */
11165 	if ((rack->rc_in_persist != 0) &&
11166 	    (tp->snd_wnd >= min((rack->r_ctl.rc_high_rwnd/2),
11167 			       rack->r_ctl.rc_pace_min_segs))) {
11168 		rack_exit_persist(tp, rack, cts);
11169 	}
11170 	/* Do we enter persists? */
11171 	if ((rack->rc_in_persist == 0) &&
11172 	    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), rack->r_ctl.rc_pace_min_segs)) &&
11173 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
11174 	    (tp->snd_max == tp->snd_una) &&
11175 	    sbavail(&tp->t_inpcb->inp_socket->so_snd) &&
11176 	    (sbavail(&tp->t_inpcb->inp_socket->so_snd) > tp->snd_wnd)) {
11177 		/*
11178 		 * Here the rwnd is less than
11179 		 * the pacing size, we are established,
11180 		 * nothing is outstanding, and there is
11181 		 * data to send. Enter persists.
11182 		 */
11183 		rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
11184 	}
11185 	/*
11186 	 * If last ACK falls within this segment's sequence numbers, record
11187 	 * the timestamp. NOTE that the test is modified according to the
11188 	 * latest proposal of the tcplw@cray.com list (Braden 1993/04/26).
11189 	 */
11190 	if ((to->to_flags & TOF_TS) != 0 &&
11191 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
11192 		tp->ts_recent_age = tcp_ts_getticks();
11193 		tp->ts_recent = to->to_tsval;
11194 	}
11195 	/*
11196 	 * This is a pure ack for outstanding data.
11197 	 */
11198 	KMOD_TCPSTAT_INC(tcps_predack);
11199 
11200 	/*
11201 	 * "bad retransmit" recovery.
11202 	 */
11203 	if ((tp->t_flags & TF_PREVVALID) &&
11204 	    ((tp->t_flags & TF_RCVD_TSTMP) == 0)) {
11205 		tp->t_flags &= ~TF_PREVVALID;
11206 		if (tp->t_rxtshift == 1 &&
11207 		    (int)(ticks - tp->t_badrxtwin) < 0)
11208 			rack_cong_signal(tp, CC_RTO_ERR, th->th_ack);
11209 	}
11210 	/*
11211 	 * Recalculate the transmit timer / rtt.
11212 	 *
11213 	 * Some boxes send broken timestamp replies during the SYN+ACK
11214 	 * phase, ignore timestamps of 0 or we could calculate a huge RTT
11215 	 * and blow up the retransmit timer.
11216 	 */
11217 	acked = BYTES_THIS_ACK(tp, th);
11218 
11219 #ifdef TCP_HHOOK
11220 	/* Run HHOOK_TCP_ESTABLISHED_IN helper hooks. */
11221 	hhook_run_tcp_est_in(tp, th, to);
11222 #endif
11223 	KMOD_TCPSTAT_ADD(tcps_rcvackpack, nsegs);
11224 	KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
11225 	if (acked) {
11226 		struct mbuf *mfree;
11227 
11228 		rack_ack_received(tp, rack, th->th_ack, nsegs, CC_ACK, 0);
11229 		SOCKBUF_LOCK(&so->so_snd);
11230 		mfree = sbcut_locked(&so->so_snd, acked);
11231 		tp->snd_una = th->th_ack;
11232 		/* Note we want to hold the sb lock through the sendmap adjust */
11233 		rack_adjust_sendmap(rack, &so->so_snd, tp->snd_una);
11234 		/* Wake up the socket if we have room to write more */
11235 		rack_log_wakeup(tp,rack, &so->so_snd, acked, 2);
11236 		sowwakeup_locked(so);
11237 		m_freem(mfree);
11238 		tp->t_rxtshift = 0;
11239 		RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
11240 			      rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
11241 		rack->rc_tlp_in_progress = 0;
11242 		rack->r_ctl.rc_tlp_cnt_out = 0;
11243 		/*
11244 		 * If it is the RXT timer we want to
11245 		 * stop it, so we can restart a TLP.
11246 		 */
11247 		if (rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT)
11248 			rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
11249 #ifdef NETFLIX_HTTP_LOGGING
11250 		tcp_http_check_for_comp(rack->rc_tp, th->th_ack);
11251 #endif
11252 	}
11253 	/*
11254 	 * Let the congestion control algorithm update congestion control
11255 	 * related information. This typically means increasing the
11256 	 * congestion window.
11257 	 */
11258 	if (tp->snd_wnd < ctf_outstanding(tp)) {
11259 		/* The peer collapsed the window */
11260 		rack_collapsed_window(rack);
11261 	} else if (rack->rc_has_collapsed)
11262 		rack_un_collapse_window(rack);
11263 
11264 	/*
11265 	 * Pull snd_wl2 up to prevent seq wrap relative to th_ack.
11266 	 */
11267 	tp->snd_wl2 = th->th_ack;
11268 	tp->t_dupacks = 0;
11269 	m_freem(m);
11270 	/* ND6_HINT(tp);	 *//* Some progress has been made. */
11271 
11272 	/*
11273 	 * If all outstanding data are acked, stop retransmit timer,
11274 	 * otherwise restart timer using current (possibly backed-off)
11275 	 * value. If process is waiting for space, wakeup/selwakeup/signal.
11276 	 * If data are ready to send, let tcp_output decide between more
11277 	 * output or persist.
11278 	 */
11279 #ifdef TCPDEBUG
11280 	if (so->so_options & SO_DEBUG)
11281 		tcp_trace(TA_INPUT, ostate, tp,
11282 		    (void *)tcp_saveipgen,
11283 		    &tcp_savetcp, 0);
11284 #endif
11285 	if (under_pacing &&
11286 	    (rack->use_fixed_rate == 0) &&
11287 	    (rack->in_probe_rtt == 0) &&
11288 	    rack->rc_gp_dyn_mul &&
11289 	    rack->rc_always_pace) {
11290 		/* Check if we are dragging bottom */
11291 		rack_check_bottom_drag(tp, rack, so, acked);
11292 	}
11293 	if (tp->snd_una == tp->snd_max) {
11294 		tp->t_flags &= ~TF_PREVVALID;
11295 		rack->r_ctl.retran_during_recovery = 0;
11296 		rack->r_ctl.dsack_byte_cnt = 0;
11297 		rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
11298 		if (rack->r_ctl.rc_went_idle_time == 0)
11299 			rack->r_ctl.rc_went_idle_time = 1;
11300 		rack_log_progress_event(rack, tp, 0, PROGRESS_CLEAR, __LINE__);
11301 		if (sbavail(&tp->t_inpcb->inp_socket->so_snd) == 0)
11302 			tp->t_acktime = 0;
11303 		rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
11304 	}
11305 	if (acked && rack->r_fast_output)
11306 		rack_gain_for_fastoutput(rack, tp, so, (uint32_t)acked);
11307 	if (sbavail(&so->so_snd)) {
11308 		rack->r_wanted_output = 1;
11309 	}
11310 	return (1);
11311 }
11312 
11313 /*
11314  * Return value of 1, the TCB is unlocked and most
11315  * likely gone, return value of 0, the TCP is still
11316  * locked.
11317  */
11318 static int
11319 rack_do_syn_sent(struct mbuf *m, struct tcphdr *th, struct socket *so,
11320     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
11321     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
11322 {
11323 	int32_t ret_val = 0;
11324 	int32_t todrop;
11325 	int32_t ourfinisacked = 0;
11326 	struct tcp_rack *rack;
11327 
11328 	ctf_calc_rwin(so, tp);
11329 	/*
11330 	 * If the state is SYN_SENT: if seg contains an ACK, but not for our
11331 	 * SYN, drop the input. if seg contains a RST, then drop the
11332 	 * connection. if seg does not contain SYN, then drop it. Otherwise
11333 	 * this is an acceptable SYN segment initialize tp->rcv_nxt and
11334 	 * tp->irs if seg contains ack then advance tp->snd_una if seg
11335 	 * contains an ECE and ECN support is enabled, the stream is ECN
11336 	 * capable. if SYN has been acked change to ESTABLISHED else
11337 	 * SYN_RCVD state arrange for segment to be acked (eventually)
11338 	 * continue processing rest of data/controls.
11339 	 */
11340 	if ((thflags & TH_ACK) &&
11341 	    (SEQ_LEQ(th->th_ack, tp->iss) ||
11342 	    SEQ_GT(th->th_ack, tp->snd_max))) {
11343 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
11344 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11345 		return (1);
11346 	}
11347 	if ((thflags & (TH_ACK | TH_RST)) == (TH_ACK | TH_RST)) {
11348 		TCP_PROBE5(connect__refused, NULL, tp,
11349 		    mtod(m, const char *), tp, th);
11350 		tp = tcp_drop(tp, ECONNREFUSED);
11351 		ctf_do_drop(m, tp);
11352 		return (1);
11353 	}
11354 	if (thflags & TH_RST) {
11355 		ctf_do_drop(m, tp);
11356 		return (1);
11357 	}
11358 	if (!(thflags & TH_SYN)) {
11359 		ctf_do_drop(m, tp);
11360 		return (1);
11361 	}
11362 	tp->irs = th->th_seq;
11363 	tcp_rcvseqinit(tp);
11364 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11365 	if (thflags & TH_ACK) {
11366 		int tfo_partial = 0;
11367 
11368 		KMOD_TCPSTAT_INC(tcps_connects);
11369 		soisconnected(so);
11370 #ifdef MAC
11371 		mac_socketpeer_set_from_mbuf(m, so);
11372 #endif
11373 		/* Do window scaling on this connection? */
11374 		if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
11375 		    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
11376 			tp->rcv_scale = tp->request_r_scale;
11377 		}
11378 		tp->rcv_adv += min(tp->rcv_wnd,
11379 		    TCP_MAXWIN << tp->rcv_scale);
11380 		/*
11381 		 * If not all the data that was sent in the TFO SYN
11382 		 * has been acked, resend the remainder right away.
11383 		 */
11384 		if (IS_FASTOPEN(tp->t_flags) &&
11385 		    (tp->snd_una != tp->snd_max)) {
11386 			tp->snd_nxt = th->th_ack;
11387 			tfo_partial = 1;
11388 		}
11389 		/*
11390 		 * If there's data, delay ACK; if there's also a FIN ACKNOW
11391 		 * will be turned on later.
11392 		 */
11393 		if (DELAY_ACK(tp, tlen) && tlen != 0 && !tfo_partial) {
11394 			rack_timer_cancel(tp, rack,
11395 					  rack->r_ctl.rc_rcvtime, __LINE__);
11396 			tp->t_flags |= TF_DELACK;
11397 		} else {
11398 			rack->r_wanted_output = 1;
11399 			tp->t_flags |= TF_ACKNOW;
11400 			rack->rc_dack_toggle = 0;
11401 		}
11402 		if (((thflags & (TH_CWR | TH_ECE)) == TH_ECE) &&
11403 		    (V_tcp_do_ecn == 1)) {
11404 			tp->t_flags2 |= TF2_ECN_PERMIT;
11405 			KMOD_TCPSTAT_INC(tcps_ecn_shs);
11406 		}
11407 		if (SEQ_GT(th->th_ack, tp->snd_una)) {
11408 			/*
11409 			 * We advance snd_una for the
11410 			 * fast open case. If th_ack is
11411 			 * acknowledging data beyond
11412 			 * snd_una we can't just call
11413 			 * ack-processing since the
11414 			 * data stream in our send-map
11415 			 * will start at snd_una + 1 (one
11416 			 * beyond the SYN). If its just
11417 			 * equal we don't need to do that
11418 			 * and there is no send_map.
11419 			 */
11420 			tp->snd_una++;
11421 		}
11422 		/*
11423 		 * Received <SYN,ACK> in SYN_SENT[*] state. Transitions:
11424 		 * SYN_SENT  --> ESTABLISHED SYN_SENT* --> FIN_WAIT_1
11425 		 */
11426 		tp->t_starttime = ticks;
11427 		if (tp->t_flags & TF_NEEDFIN) {
11428 			tcp_state_change(tp, TCPS_FIN_WAIT_1);
11429 			tp->t_flags &= ~TF_NEEDFIN;
11430 			thflags &= ~TH_SYN;
11431 		} else {
11432 			tcp_state_change(tp, TCPS_ESTABLISHED);
11433 			TCP_PROBE5(connect__established, NULL, tp,
11434 			    mtod(m, const char *), tp, th);
11435 			rack_cc_conn_init(tp);
11436 		}
11437 	} else {
11438 		/*
11439 		 * Received initial SYN in SYN-SENT[*] state => simultaneous
11440 		 * open.  If segment contains CC option and there is a
11441 		 * cached CC, apply TAO test. If it succeeds, connection is *
11442 		 * half-synchronized. Otherwise, do 3-way handshake:
11443 		 * SYN-SENT -> SYN-RECEIVED SYN-SENT* -> SYN-RECEIVED* If
11444 		 * there was no CC option, clear cached CC value.
11445 		 */
11446 		tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
11447 		tcp_state_change(tp, TCPS_SYN_RECEIVED);
11448 	}
11449 	INP_WLOCK_ASSERT(tp->t_inpcb);
11450 	/*
11451 	 * Advance th->th_seq to correspond to first data byte. If data,
11452 	 * trim to stay within window, dropping FIN if necessary.
11453 	 */
11454 	th->th_seq++;
11455 	if (tlen > tp->rcv_wnd) {
11456 		todrop = tlen - tp->rcv_wnd;
11457 		m_adj(m, -todrop);
11458 		tlen = tp->rcv_wnd;
11459 		thflags &= ~TH_FIN;
11460 		KMOD_TCPSTAT_INC(tcps_rcvpackafterwin);
11461 		KMOD_TCPSTAT_ADD(tcps_rcvbyteafterwin, todrop);
11462 	}
11463 	tp->snd_wl1 = th->th_seq - 1;
11464 	tp->rcv_up = th->th_seq;
11465 	/*
11466 	 * Client side of transaction: already sent SYN and data. If the
11467 	 * remote host used T/TCP to validate the SYN, our data will be
11468 	 * ACK'd; if so, enter normal data segment processing in the middle
11469 	 * of step 5, ack processing. Otherwise, goto step 6.
11470 	 */
11471 	if (thflags & TH_ACK) {
11472 		/* For syn-sent we need to possibly update the rtt */
11473 		if ((to->to_flags & TOF_TS) != 0 && to->to_tsecr) {
11474 			uint32_t t, mcts;
11475 
11476 			mcts = tcp_ts_getticks();
11477 			t = (mcts - to->to_tsecr) * HPTS_USEC_IN_MSEC;
11478 			if (!tp->t_rttlow || tp->t_rttlow > t)
11479 				tp->t_rttlow = t;
11480 			rack_log_rtt_sample_calc(rack, t, (to->to_tsecr * 1000), (mcts * 1000), 4);
11481 			tcp_rack_xmit_timer(rack, t + 1, 1, t, 0, NULL, 2);
11482 			tcp_rack_xmit_timer_commit(rack, tp);
11483 		}
11484 		if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val))
11485 			return (ret_val);
11486 		/* We may have changed to FIN_WAIT_1 above */
11487 		if (tp->t_state == TCPS_FIN_WAIT_1) {
11488 			/*
11489 			 * In FIN_WAIT_1 STATE in addition to the processing
11490 			 * for the ESTABLISHED state if our FIN is now
11491 			 * acknowledged then enter FIN_WAIT_2.
11492 			 */
11493 			if (ourfinisacked) {
11494 				/*
11495 				 * If we can't receive any more data, then
11496 				 * closing user can proceed. Starting the
11497 				 * timer is contrary to the specification,
11498 				 * but if we don't get a FIN we'll hang
11499 				 * forever.
11500 				 *
11501 				 * XXXjl: we should release the tp also, and
11502 				 * use a compressed state.
11503 				 */
11504 				if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
11505 					soisdisconnected(so);
11506 					tcp_timer_activate(tp, TT_2MSL,
11507 					    (tcp_fast_finwait2_recycle ?
11508 					    tcp_finwait2_timeout :
11509 					    TP_MAXIDLE(tp)));
11510 				}
11511 				tcp_state_change(tp, TCPS_FIN_WAIT_2);
11512 			}
11513 		}
11514 	}
11515 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11516 	   tiwin, thflags, nxt_pkt));
11517 }
11518 
11519 /*
11520  * Return value of 1, the TCB is unlocked and most
11521  * likely gone, return value of 0, the TCP is still
11522  * locked.
11523  */
11524 static int
11525 rack_do_syn_recv(struct mbuf *m, struct tcphdr *th, struct socket *so,
11526     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
11527     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
11528 {
11529 	struct tcp_rack *rack;
11530 	int32_t ret_val = 0;
11531 	int32_t ourfinisacked = 0;
11532 
11533 	ctf_calc_rwin(so, tp);
11534 	if ((thflags & TH_ACK) &&
11535 	    (SEQ_LEQ(th->th_ack, tp->snd_una) ||
11536 	    SEQ_GT(th->th_ack, tp->snd_max))) {
11537 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
11538 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11539 		return (1);
11540 	}
11541 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11542 	if (IS_FASTOPEN(tp->t_flags)) {
11543 		/*
11544 		 * When a TFO connection is in SYN_RECEIVED, the
11545 		 * only valid packets are the initial SYN, a
11546 		 * retransmit/copy of the initial SYN (possibly with
11547 		 * a subset of the original data), a valid ACK, a
11548 		 * FIN, or a RST.
11549 		 */
11550 		if ((thflags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) {
11551 			tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
11552 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11553 			return (1);
11554 		} else if (thflags & TH_SYN) {
11555 			/* non-initial SYN is ignored */
11556 			if ((rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT) ||
11557 			    (rack->r_ctl.rc_hpts_flags & PACE_TMR_TLP) ||
11558 			    (rack->r_ctl.rc_hpts_flags & PACE_TMR_RACK)) {
11559 				ctf_do_drop(m, NULL);
11560 				return (0);
11561 			}
11562 		} else if (!(thflags & (TH_ACK | TH_FIN | TH_RST))) {
11563 			ctf_do_drop(m, NULL);
11564 			return (0);
11565 		}
11566 	}
11567 
11568 	if ((thflags & TH_RST) ||
11569 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
11570 		return (__ctf_process_rst(m, th, so, tp,
11571 					  &rack->r_ctl.challenge_ack_ts,
11572 					  &rack->r_ctl.challenge_ack_cnt));
11573 	/*
11574 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
11575 	 * it's less than ts_recent, drop it.
11576 	 */
11577 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
11578 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
11579 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
11580 			return (ret_val);
11581 	}
11582 	/*
11583 	 * In the SYN-RECEIVED state, validate that the packet belongs to
11584 	 * this connection before trimming the data to fit the receive
11585 	 * window.  Check the sequence number versus IRS since we know the
11586 	 * sequence numbers haven't wrapped.  This is a partial fix for the
11587 	 * "LAND" DoS attack.
11588 	 */
11589 	if (SEQ_LT(th->th_seq, tp->irs)) {
11590 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
11591 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11592 		return (1);
11593 	}
11594 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
11595 			      &rack->r_ctl.challenge_ack_ts,
11596 			      &rack->r_ctl.challenge_ack_cnt)) {
11597 		return (ret_val);
11598 	}
11599 	/*
11600 	 * If last ACK falls within this segment's sequence numbers, record
11601 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
11602 	 * from the latest proposal of the tcplw@cray.com list (Braden
11603 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
11604 	 * with our earlier PAWS tests, so this check should be solely
11605 	 * predicated on the sequence space of this segment. 3) That we
11606 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
11607 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
11608 	 * SEG.Len, This modified check allows us to overcome RFC1323's
11609 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
11610 	 * p.869. In such cases, we can still calculate the RTT correctly
11611 	 * when RCV.NXT == Last.ACK.Sent.
11612 	 */
11613 	if ((to->to_flags & TOF_TS) != 0 &&
11614 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
11615 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
11616 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
11617 		tp->ts_recent_age = tcp_ts_getticks();
11618 		tp->ts_recent = to->to_tsval;
11619 	}
11620 	tp->snd_wnd = tiwin;
11621 	rack_validate_fo_sendwin_up(tp, rack);
11622 	/*
11623 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
11624 	 * is on (half-synchronized state), then queue data for later
11625 	 * processing; else drop segment and return.
11626 	 */
11627 	if ((thflags & TH_ACK) == 0) {
11628 		if (IS_FASTOPEN(tp->t_flags)) {
11629 			rack_cc_conn_init(tp);
11630 		}
11631 		return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11632 		    tiwin, thflags, nxt_pkt));
11633 	}
11634 	KMOD_TCPSTAT_INC(tcps_connects);
11635 	soisconnected(so);
11636 	/* Do window scaling? */
11637 	if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
11638 	    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
11639 		tp->rcv_scale = tp->request_r_scale;
11640 	}
11641 	/*
11642 	 * Make transitions: SYN-RECEIVED  -> ESTABLISHED SYN-RECEIVED* ->
11643 	 * FIN-WAIT-1
11644 	 */
11645 	tp->t_starttime = ticks;
11646 	if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) {
11647 		tcp_fastopen_decrement_counter(tp->t_tfo_pending);
11648 		tp->t_tfo_pending = NULL;
11649 	}
11650 	if (tp->t_flags & TF_NEEDFIN) {
11651 		tcp_state_change(tp, TCPS_FIN_WAIT_1);
11652 		tp->t_flags &= ~TF_NEEDFIN;
11653 	} else {
11654 		tcp_state_change(tp, TCPS_ESTABLISHED);
11655 		TCP_PROBE5(accept__established, NULL, tp,
11656 		    mtod(m, const char *), tp, th);
11657 		/*
11658 		 * TFO connections call cc_conn_init() during SYN
11659 		 * processing.  Calling it again here for such connections
11660 		 * is not harmless as it would undo the snd_cwnd reduction
11661 		 * that occurs when a TFO SYN|ACK is retransmitted.
11662 		 */
11663 		if (!IS_FASTOPEN(tp->t_flags))
11664 			rack_cc_conn_init(tp);
11665 	}
11666 	/*
11667 	 * Account for the ACK of our SYN prior to
11668 	 * regular ACK processing below, except for
11669 	 * simultaneous SYN, which is handled later.
11670 	 */
11671 	if (SEQ_GT(th->th_ack, tp->snd_una) && !(tp->t_flags & TF_NEEDSYN))
11672 		tp->snd_una++;
11673 	/*
11674 	 * If segment contains data or ACK, will call tcp_reass() later; if
11675 	 * not, do so now to pass queued data to user.
11676 	 */
11677 	if (tlen == 0 && (thflags & TH_FIN) == 0) {
11678 		(void) tcp_reass(tp, (struct tcphdr *)0, NULL, 0,
11679 		    (struct mbuf *)0);
11680 		if (tp->t_flags & TF_WAKESOR) {
11681 			tp->t_flags &= ~TF_WAKESOR;
11682 			/* NB: sorwakeup_locked() does an implicit unlock. */
11683 			sorwakeup_locked(so);
11684 		}
11685 	}
11686 	tp->snd_wl1 = th->th_seq - 1;
11687 	/* For syn-recv we need to possibly update the rtt */
11688 	if ((to->to_flags & TOF_TS) != 0 && to->to_tsecr) {
11689 		uint32_t t, mcts;
11690 
11691 		mcts = tcp_ts_getticks();
11692 		t = (mcts - to->to_tsecr) * HPTS_USEC_IN_MSEC;
11693 		if (!tp->t_rttlow || tp->t_rttlow > t)
11694 			tp->t_rttlow = t;
11695 		rack_log_rtt_sample_calc(rack, t, (to->to_tsecr * 1000), (mcts * 1000), 5);
11696 		tcp_rack_xmit_timer(rack, t + 1, 1, t, 0, NULL, 2);
11697 		tcp_rack_xmit_timer_commit(rack, tp);
11698 	}
11699 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
11700 		return (ret_val);
11701 	}
11702 	if (tp->t_state == TCPS_FIN_WAIT_1) {
11703 		/* We could have went to FIN_WAIT_1 (or EST) above */
11704 		/*
11705 		 * In FIN_WAIT_1 STATE in addition to the processing for the
11706 		 * ESTABLISHED state if our FIN is now acknowledged then
11707 		 * enter FIN_WAIT_2.
11708 		 */
11709 		if (ourfinisacked) {
11710 			/*
11711 			 * If we can't receive any more data, then closing
11712 			 * user can proceed. Starting the timer is contrary
11713 			 * to the specification, but if we don't get a FIN
11714 			 * we'll hang forever.
11715 			 *
11716 			 * XXXjl: we should release the tp also, and use a
11717 			 * compressed state.
11718 			 */
11719 			if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
11720 				soisdisconnected(so);
11721 				tcp_timer_activate(tp, TT_2MSL,
11722 				    (tcp_fast_finwait2_recycle ?
11723 				    tcp_finwait2_timeout :
11724 				    TP_MAXIDLE(tp)));
11725 			}
11726 			tcp_state_change(tp, TCPS_FIN_WAIT_2);
11727 		}
11728 	}
11729 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11730 	    tiwin, thflags, nxt_pkt));
11731 }
11732 
11733 /*
11734  * Return value of 1, the TCB is unlocked and most
11735  * likely gone, return value of 0, the TCP is still
11736  * locked.
11737  */
11738 static int
11739 rack_do_established(struct mbuf *m, struct tcphdr *th, struct socket *so,
11740     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
11741     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
11742 {
11743 	int32_t ret_val = 0;
11744 	struct tcp_rack *rack;
11745 
11746 	/*
11747 	 * Header prediction: check for the two common cases of a
11748 	 * uni-directional data xfer.  If the packet has no control flags,
11749 	 * is in-sequence, the window didn't change and we're not
11750 	 * retransmitting, it's a candidate.  If the length is zero and the
11751 	 * ack moved forward, we're the sender side of the xfer.  Just free
11752 	 * the data acked & wake any higher level process that was blocked
11753 	 * waiting for space.  If the length is non-zero and the ack didn't
11754 	 * move, we're the receiver side.  If we're getting packets in-order
11755 	 * (the reassembly queue is empty), add the data toc The socket
11756 	 * buffer and note that we need a delayed ack. Make sure that the
11757 	 * hidden state-flags are also off. Since we check for
11758 	 * TCPS_ESTABLISHED first, it can only be TH_NEEDSYN.
11759 	 */
11760 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11761 	if (__predict_true(((to->to_flags & TOF_SACK) == 0)) &&
11762 	    __predict_true((thflags & (TH_SYN | TH_FIN | TH_RST | TH_ACK)) == TH_ACK) &&
11763 	    __predict_true(SEGQ_EMPTY(tp)) &&
11764 	    __predict_true(th->th_seq == tp->rcv_nxt)) {
11765 		if (tlen == 0) {
11766 			if (rack_fastack(m, th, so, tp, to, drop_hdrlen, tlen,
11767 			    tiwin, nxt_pkt, rack->r_ctl.rc_rcvtime)) {
11768 				return (0);
11769 			}
11770 		} else {
11771 			if (rack_do_fastnewdata(m, th, so, tp, to, drop_hdrlen, tlen,
11772 			    tiwin, nxt_pkt, iptos)) {
11773 				return (0);
11774 			}
11775 		}
11776 	}
11777 	ctf_calc_rwin(so, tp);
11778 
11779 	if ((thflags & TH_RST) ||
11780 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
11781 		return (__ctf_process_rst(m, th, so, tp,
11782 					  &rack->r_ctl.challenge_ack_ts,
11783 					  &rack->r_ctl.challenge_ack_cnt));
11784 
11785 	/*
11786 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
11787 	 * synchronized state.
11788 	 */
11789 	if (thflags & TH_SYN) {
11790 		ctf_challenge_ack(m, th, tp, &ret_val);
11791 		return (ret_val);
11792 	}
11793 	/*
11794 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
11795 	 * it's less than ts_recent, drop it.
11796 	 */
11797 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
11798 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
11799 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
11800 			return (ret_val);
11801 	}
11802 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
11803 			      &rack->r_ctl.challenge_ack_ts,
11804 			      &rack->r_ctl.challenge_ack_cnt)) {
11805 		return (ret_val);
11806 	}
11807 	/*
11808 	 * If last ACK falls within this segment's sequence numbers, record
11809 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
11810 	 * from the latest proposal of the tcplw@cray.com list (Braden
11811 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
11812 	 * with our earlier PAWS tests, so this check should be solely
11813 	 * predicated on the sequence space of this segment. 3) That we
11814 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
11815 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
11816 	 * SEG.Len, This modified check allows us to overcome RFC1323's
11817 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
11818 	 * p.869. In such cases, we can still calculate the RTT correctly
11819 	 * when RCV.NXT == Last.ACK.Sent.
11820 	 */
11821 	if ((to->to_flags & TOF_TS) != 0 &&
11822 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
11823 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
11824 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
11825 		tp->ts_recent_age = tcp_ts_getticks();
11826 		tp->ts_recent = to->to_tsval;
11827 	}
11828 	/*
11829 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
11830 	 * is on (half-synchronized state), then queue data for later
11831 	 * processing; else drop segment and return.
11832 	 */
11833 	if ((thflags & TH_ACK) == 0) {
11834 		if (tp->t_flags & TF_NEEDSYN) {
11835 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11836 			    tiwin, thflags, nxt_pkt));
11837 
11838 		} else if (tp->t_flags & TF_ACKNOW) {
11839 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
11840 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
11841 			return (ret_val);
11842 		} else {
11843 			ctf_do_drop(m, NULL);
11844 			return (0);
11845 		}
11846 	}
11847 	/*
11848 	 * Ack processing.
11849 	 */
11850 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) {
11851 		return (ret_val);
11852 	}
11853 	if (sbavail(&so->so_snd)) {
11854 		if (ctf_progress_timeout_check(tp, true)) {
11855 			rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
11856 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
11857 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11858 			return (1);
11859 		}
11860 	}
11861 	/* State changes only happen in rack_process_data() */
11862 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11863 	    tiwin, thflags, nxt_pkt));
11864 }
11865 
11866 /*
11867  * Return value of 1, the TCB is unlocked and most
11868  * likely gone, return value of 0, the TCP is still
11869  * locked.
11870  */
11871 static int
11872 rack_do_close_wait(struct mbuf *m, struct tcphdr *th, struct socket *so,
11873     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
11874     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
11875 {
11876 	int32_t ret_val = 0;
11877 	struct tcp_rack *rack;
11878 
11879 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11880 	ctf_calc_rwin(so, tp);
11881 	if ((thflags & TH_RST) ||
11882 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
11883 		return (__ctf_process_rst(m, th, so, tp,
11884 					  &rack->r_ctl.challenge_ack_ts,
11885 					  &rack->r_ctl.challenge_ack_cnt));
11886 	/*
11887 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
11888 	 * synchronized state.
11889 	 */
11890 	if (thflags & TH_SYN) {
11891 		ctf_challenge_ack(m, th, tp, &ret_val);
11892 		return (ret_val);
11893 	}
11894 	/*
11895 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
11896 	 * it's less than ts_recent, drop it.
11897 	 */
11898 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
11899 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
11900 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
11901 			return (ret_val);
11902 	}
11903 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
11904 			      &rack->r_ctl.challenge_ack_ts,
11905 			      &rack->r_ctl.challenge_ack_cnt)) {
11906 		return (ret_val);
11907 	}
11908 	/*
11909 	 * If last ACK falls within this segment's sequence numbers, record
11910 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
11911 	 * from the latest proposal of the tcplw@cray.com list (Braden
11912 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
11913 	 * with our earlier PAWS tests, so this check should be solely
11914 	 * predicated on the sequence space of this segment. 3) That we
11915 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
11916 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
11917 	 * SEG.Len, This modified check allows us to overcome RFC1323's
11918 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
11919 	 * p.869. In such cases, we can still calculate the RTT correctly
11920 	 * when RCV.NXT == Last.ACK.Sent.
11921 	 */
11922 	if ((to->to_flags & TOF_TS) != 0 &&
11923 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
11924 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
11925 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
11926 		tp->ts_recent_age = tcp_ts_getticks();
11927 		tp->ts_recent = to->to_tsval;
11928 	}
11929 	/*
11930 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
11931 	 * is on (half-synchronized state), then queue data for later
11932 	 * processing; else drop segment and return.
11933 	 */
11934 	if ((thflags & TH_ACK) == 0) {
11935 		if (tp->t_flags & TF_NEEDSYN) {
11936 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11937 			    tiwin, thflags, nxt_pkt));
11938 
11939 		} else if (tp->t_flags & TF_ACKNOW) {
11940 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
11941 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
11942 			return (ret_val);
11943 		} else {
11944 			ctf_do_drop(m, NULL);
11945 			return (0);
11946 		}
11947 	}
11948 	/*
11949 	 * Ack processing.
11950 	 */
11951 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) {
11952 		return (ret_val);
11953 	}
11954 	if (sbavail(&so->so_snd)) {
11955 		if (ctf_progress_timeout_check(tp, true)) {
11956 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
11957 						tp, tick, PROGRESS_DROP, __LINE__);
11958 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
11959 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11960 			return (1);
11961 		}
11962 	}
11963 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11964 	    tiwin, thflags, nxt_pkt));
11965 }
11966 
11967 static int
11968 rack_check_data_after_close(struct mbuf *m,
11969     struct tcpcb *tp, int32_t *tlen, struct tcphdr *th, struct socket *so)
11970 {
11971 	struct tcp_rack *rack;
11972 
11973 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11974 	if (rack->rc_allow_data_af_clo == 0) {
11975 	close_now:
11976 		tcp_log_end_status(tp, TCP_EI_STATUS_DATA_A_CLOSE);
11977 		/* tcp_close will kill the inp pre-log the Reset */
11978 		tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
11979 		tp = tcp_close(tp);
11980 		KMOD_TCPSTAT_INC(tcps_rcvafterclose);
11981 		ctf_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, (*tlen));
11982 		return (1);
11983 	}
11984 	if (sbavail(&so->so_snd) == 0)
11985 		goto close_now;
11986 	/* Ok we allow data that is ignored and a followup reset */
11987 	tcp_log_end_status(tp, TCP_EI_STATUS_DATA_A_CLOSE);
11988 	tp->rcv_nxt = th->th_seq + *tlen;
11989 	tp->t_flags2 |= TF2_DROP_AF_DATA;
11990 	rack->r_wanted_output = 1;
11991 	*tlen = 0;
11992 	return (0);
11993 }
11994 
11995 /*
11996  * Return value of 1, the TCB is unlocked and most
11997  * likely gone, return value of 0, the TCP is still
11998  * locked.
11999  */
12000 static int
12001 rack_do_fin_wait_1(struct mbuf *m, struct tcphdr *th, struct socket *so,
12002     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
12003     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
12004 {
12005 	int32_t ret_val = 0;
12006 	int32_t ourfinisacked = 0;
12007 	struct tcp_rack *rack;
12008 
12009 	rack = (struct tcp_rack *)tp->t_fb_ptr;
12010 	ctf_calc_rwin(so, tp);
12011 
12012 	if ((thflags & TH_RST) ||
12013 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
12014 		return (__ctf_process_rst(m, th, so, tp,
12015 					  &rack->r_ctl.challenge_ack_ts,
12016 					  &rack->r_ctl.challenge_ack_cnt));
12017 	/*
12018 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
12019 	 * synchronized state.
12020 	 */
12021 	if (thflags & TH_SYN) {
12022 		ctf_challenge_ack(m, th, tp, &ret_val);
12023 		return (ret_val);
12024 	}
12025 	/*
12026 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
12027 	 * it's less than ts_recent, drop it.
12028 	 */
12029 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
12030 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
12031 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
12032 			return (ret_val);
12033 	}
12034 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
12035 			      &rack->r_ctl.challenge_ack_ts,
12036 			      &rack->r_ctl.challenge_ack_cnt)) {
12037 		return (ret_val);
12038 	}
12039 	/*
12040 	 * If new data are received on a connection after the user processes
12041 	 * are gone, then RST the other end.
12042 	 */
12043 	if ((so->so_state & SS_NOFDREF) && tlen) {
12044 		if (rack_check_data_after_close(m, tp, &tlen, th, so))
12045 			return (1);
12046 	}
12047 	/*
12048 	 * If last ACK falls within this segment's sequence numbers, record
12049 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
12050 	 * from the latest proposal of the tcplw@cray.com list (Braden
12051 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
12052 	 * with our earlier PAWS tests, so this check should be solely
12053 	 * predicated on the sequence space of this segment. 3) That we
12054 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
12055 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
12056 	 * SEG.Len, This modified check allows us to overcome RFC1323's
12057 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
12058 	 * p.869. In such cases, we can still calculate the RTT correctly
12059 	 * when RCV.NXT == Last.ACK.Sent.
12060 	 */
12061 	if ((to->to_flags & TOF_TS) != 0 &&
12062 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
12063 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
12064 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
12065 		tp->ts_recent_age = tcp_ts_getticks();
12066 		tp->ts_recent = to->to_tsval;
12067 	}
12068 	/*
12069 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
12070 	 * is on (half-synchronized state), then queue data for later
12071 	 * processing; else drop segment and return.
12072 	 */
12073 	if ((thflags & TH_ACK) == 0) {
12074 		if (tp->t_flags & TF_NEEDSYN) {
12075 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12076 			    tiwin, thflags, nxt_pkt));
12077 		} else if (tp->t_flags & TF_ACKNOW) {
12078 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
12079 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
12080 			return (ret_val);
12081 		} else {
12082 			ctf_do_drop(m, NULL);
12083 			return (0);
12084 		}
12085 	}
12086 	/*
12087 	 * Ack processing.
12088 	 */
12089 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
12090 		return (ret_val);
12091 	}
12092 	if (ourfinisacked) {
12093 		/*
12094 		 * If we can't receive any more data, then closing user can
12095 		 * proceed. Starting the timer is contrary to the
12096 		 * specification, but if we don't get a FIN we'll hang
12097 		 * forever.
12098 		 *
12099 		 * XXXjl: we should release the tp also, and use a
12100 		 * compressed state.
12101 		 */
12102 		if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
12103 			soisdisconnected(so);
12104 			tcp_timer_activate(tp, TT_2MSL,
12105 			    (tcp_fast_finwait2_recycle ?
12106 			    tcp_finwait2_timeout :
12107 			    TP_MAXIDLE(tp)));
12108 		}
12109 		tcp_state_change(tp, TCPS_FIN_WAIT_2);
12110 	}
12111 	if (sbavail(&so->so_snd)) {
12112 		if (ctf_progress_timeout_check(tp, true)) {
12113 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
12114 						tp, tick, PROGRESS_DROP, __LINE__);
12115 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
12116 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
12117 			return (1);
12118 		}
12119 	}
12120 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12121 	    tiwin, thflags, nxt_pkt));
12122 }
12123 
12124 /*
12125  * Return value of 1, the TCB is unlocked and most
12126  * likely gone, return value of 0, the TCP is still
12127  * locked.
12128  */
12129 static int
12130 rack_do_closing(struct mbuf *m, struct tcphdr *th, struct socket *so,
12131     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
12132     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
12133 {
12134 	int32_t ret_val = 0;
12135 	int32_t ourfinisacked = 0;
12136 	struct tcp_rack *rack;
12137 
12138 	rack = (struct tcp_rack *)tp->t_fb_ptr;
12139 	ctf_calc_rwin(so, tp);
12140 
12141 	if ((thflags & TH_RST) ||
12142 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
12143 		return (__ctf_process_rst(m, th, so, tp,
12144 					  &rack->r_ctl.challenge_ack_ts,
12145 					  &rack->r_ctl.challenge_ack_cnt));
12146 	/*
12147 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
12148 	 * synchronized state.
12149 	 */
12150 	if (thflags & TH_SYN) {
12151 		ctf_challenge_ack(m, th, tp, &ret_val);
12152 		return (ret_val);
12153 	}
12154 	/*
12155 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
12156 	 * it's less than ts_recent, drop it.
12157 	 */
12158 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
12159 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
12160 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
12161 			return (ret_val);
12162 	}
12163 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
12164 			      &rack->r_ctl.challenge_ack_ts,
12165 			      &rack->r_ctl.challenge_ack_cnt)) {
12166 		return (ret_val);
12167 	}
12168 	/*
12169 	 * If new data are received on a connection after the user processes
12170 	 * are gone, then RST the other end.
12171 	 */
12172 	if ((so->so_state & SS_NOFDREF) && tlen) {
12173 		if (rack_check_data_after_close(m, tp, &tlen, th, so))
12174 			return (1);
12175 	}
12176 	/*
12177 	 * If last ACK falls within this segment's sequence numbers, record
12178 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
12179 	 * from the latest proposal of the tcplw@cray.com list (Braden
12180 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
12181 	 * with our earlier PAWS tests, so this check should be solely
12182 	 * predicated on the sequence space of this segment. 3) That we
12183 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
12184 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
12185 	 * SEG.Len, This modified check allows us to overcome RFC1323's
12186 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
12187 	 * p.869. In such cases, we can still calculate the RTT correctly
12188 	 * when RCV.NXT == Last.ACK.Sent.
12189 	 */
12190 	if ((to->to_flags & TOF_TS) != 0 &&
12191 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
12192 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
12193 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
12194 		tp->ts_recent_age = tcp_ts_getticks();
12195 		tp->ts_recent = to->to_tsval;
12196 	}
12197 	/*
12198 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
12199 	 * is on (half-synchronized state), then queue data for later
12200 	 * processing; else drop segment and return.
12201 	 */
12202 	if ((thflags & TH_ACK) == 0) {
12203 		if (tp->t_flags & TF_NEEDSYN) {
12204 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12205 			    tiwin, thflags, nxt_pkt));
12206 		} else if (tp->t_flags & TF_ACKNOW) {
12207 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
12208 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
12209 			return (ret_val);
12210 		} else {
12211 			ctf_do_drop(m, NULL);
12212 			return (0);
12213 		}
12214 	}
12215 	/*
12216 	 * Ack processing.
12217 	 */
12218 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
12219 		return (ret_val);
12220 	}
12221 	if (ourfinisacked) {
12222 		tcp_twstart(tp);
12223 		m_freem(m);
12224 		return (1);
12225 	}
12226 	if (sbavail(&so->so_snd)) {
12227 		if (ctf_progress_timeout_check(tp, true)) {
12228 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
12229 						tp, tick, PROGRESS_DROP, __LINE__);
12230 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
12231 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
12232 			return (1);
12233 		}
12234 	}
12235 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12236 	    tiwin, thflags, nxt_pkt));
12237 }
12238 
12239 /*
12240  * Return value of 1, the TCB is unlocked and most
12241  * likely gone, return value of 0, the TCP is still
12242  * locked.
12243  */
12244 static int
12245 rack_do_lastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
12246     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
12247     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
12248 {
12249 	int32_t ret_val = 0;
12250 	int32_t ourfinisacked = 0;
12251 	struct tcp_rack *rack;
12252 
12253 	rack = (struct tcp_rack *)tp->t_fb_ptr;
12254 	ctf_calc_rwin(so, tp);
12255 
12256 	if ((thflags & TH_RST) ||
12257 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
12258 		return (__ctf_process_rst(m, th, so, tp,
12259 					  &rack->r_ctl.challenge_ack_ts,
12260 					  &rack->r_ctl.challenge_ack_cnt));
12261 	/*
12262 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
12263 	 * synchronized state.
12264 	 */
12265 	if (thflags & TH_SYN) {
12266 		ctf_challenge_ack(m, th, tp, &ret_val);
12267 		return (ret_val);
12268 	}
12269 	/*
12270 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
12271 	 * it's less than ts_recent, drop it.
12272 	 */
12273 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
12274 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
12275 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
12276 			return (ret_val);
12277 	}
12278 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
12279 			      &rack->r_ctl.challenge_ack_ts,
12280 			      &rack->r_ctl.challenge_ack_cnt)) {
12281 		return (ret_val);
12282 	}
12283 	/*
12284 	 * If new data are received on a connection after the user processes
12285 	 * are gone, then RST the other end.
12286 	 */
12287 	if ((so->so_state & SS_NOFDREF) && tlen) {
12288 		if (rack_check_data_after_close(m, tp, &tlen, th, so))
12289 			return (1);
12290 	}
12291 	/*
12292 	 * If last ACK falls within this segment's sequence numbers, record
12293 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
12294 	 * from the latest proposal of the tcplw@cray.com list (Braden
12295 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
12296 	 * with our earlier PAWS tests, so this check should be solely
12297 	 * predicated on the sequence space of this segment. 3) That we
12298 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
12299 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
12300 	 * SEG.Len, This modified check allows us to overcome RFC1323's
12301 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
12302 	 * p.869. In such cases, we can still calculate the RTT correctly
12303 	 * when RCV.NXT == Last.ACK.Sent.
12304 	 */
12305 	if ((to->to_flags & TOF_TS) != 0 &&
12306 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
12307 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
12308 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
12309 		tp->ts_recent_age = tcp_ts_getticks();
12310 		tp->ts_recent = to->to_tsval;
12311 	}
12312 	/*
12313 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
12314 	 * is on (half-synchronized state), then queue data for later
12315 	 * processing; else drop segment and return.
12316 	 */
12317 	if ((thflags & TH_ACK) == 0) {
12318 		if (tp->t_flags & TF_NEEDSYN) {
12319 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12320 			    tiwin, thflags, nxt_pkt));
12321 		} else if (tp->t_flags & TF_ACKNOW) {
12322 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
12323 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
12324 			return (ret_val);
12325 		} else {
12326 			ctf_do_drop(m, NULL);
12327 			return (0);
12328 		}
12329 	}
12330 	/*
12331 	 * case TCPS_LAST_ACK: Ack processing.
12332 	 */
12333 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
12334 		return (ret_val);
12335 	}
12336 	if (ourfinisacked) {
12337 		tp = tcp_close(tp);
12338 		ctf_do_drop(m, tp);
12339 		return (1);
12340 	}
12341 	if (sbavail(&so->so_snd)) {
12342 		if (ctf_progress_timeout_check(tp, true)) {
12343 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
12344 						tp, tick, PROGRESS_DROP, __LINE__);
12345 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
12346 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
12347 			return (1);
12348 		}
12349 	}
12350 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12351 	    tiwin, thflags, nxt_pkt));
12352 }
12353 
12354 /*
12355  * Return value of 1, the TCB is unlocked and most
12356  * likely gone, return value of 0, the TCP is still
12357  * locked.
12358  */
12359 static int
12360 rack_do_fin_wait_2(struct mbuf *m, struct tcphdr *th, struct socket *so,
12361     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
12362     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
12363 {
12364 	int32_t ret_val = 0;
12365 	int32_t ourfinisacked = 0;
12366 	struct tcp_rack *rack;
12367 
12368 	rack = (struct tcp_rack *)tp->t_fb_ptr;
12369 	ctf_calc_rwin(so, tp);
12370 
12371 	/* Reset receive buffer auto scaling when not in bulk receive mode. */
12372 	if ((thflags & TH_RST) ||
12373 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
12374 		return (__ctf_process_rst(m, th, so, tp,
12375 					  &rack->r_ctl.challenge_ack_ts,
12376 					  &rack->r_ctl.challenge_ack_cnt));
12377 	/*
12378 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
12379 	 * synchronized state.
12380 	 */
12381 	if (thflags & TH_SYN) {
12382 		ctf_challenge_ack(m, th, tp, &ret_val);
12383 		return (ret_val);
12384 	}
12385 	/*
12386 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
12387 	 * it's less than ts_recent, drop it.
12388 	 */
12389 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
12390 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
12391 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
12392 			return (ret_val);
12393 	}
12394 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
12395 			      &rack->r_ctl.challenge_ack_ts,
12396 			      &rack->r_ctl.challenge_ack_cnt)) {
12397 		return (ret_val);
12398 	}
12399 	/*
12400 	 * If new data are received on a connection after the user processes
12401 	 * are gone, then RST the other end.
12402 	 */
12403 	if ((so->so_state & SS_NOFDREF) &&
12404 	    tlen) {
12405 		if (rack_check_data_after_close(m, tp, &tlen, th, so))
12406 			return (1);
12407 	}
12408 	/*
12409 	 * If last ACK falls within this segment's sequence numbers, record
12410 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
12411 	 * from the latest proposal of the tcplw@cray.com list (Braden
12412 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
12413 	 * with our earlier PAWS tests, so this check should be solely
12414 	 * predicated on the sequence space of this segment. 3) That we
12415 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
12416 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
12417 	 * SEG.Len, This modified check allows us to overcome RFC1323's
12418 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
12419 	 * p.869. In such cases, we can still calculate the RTT correctly
12420 	 * when RCV.NXT == Last.ACK.Sent.
12421 	 */
12422 	if ((to->to_flags & TOF_TS) != 0 &&
12423 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
12424 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
12425 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
12426 		tp->ts_recent_age = tcp_ts_getticks();
12427 		tp->ts_recent = to->to_tsval;
12428 	}
12429 	/*
12430 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
12431 	 * is on (half-synchronized state), then queue data for later
12432 	 * processing; else drop segment and return.
12433 	 */
12434 	if ((thflags & TH_ACK) == 0) {
12435 		if (tp->t_flags & TF_NEEDSYN) {
12436 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12437 			    tiwin, thflags, nxt_pkt));
12438 		} else if (tp->t_flags & TF_ACKNOW) {
12439 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
12440 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
12441 			return (ret_val);
12442 		} else {
12443 			ctf_do_drop(m, NULL);
12444 			return (0);
12445 		}
12446 	}
12447 	/*
12448 	 * Ack processing.
12449 	 */
12450 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
12451 		return (ret_val);
12452 	}
12453 	if (sbavail(&so->so_snd)) {
12454 		if (ctf_progress_timeout_check(tp, true)) {
12455 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
12456 						tp, tick, PROGRESS_DROP, __LINE__);
12457 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
12458 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
12459 			return (1);
12460 		}
12461 	}
12462 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12463 	    tiwin, thflags, nxt_pkt));
12464 }
12465 
12466 static void inline
12467 rack_clear_rate_sample(struct tcp_rack *rack)
12468 {
12469 	rack->r_ctl.rack_rs.rs_flags = RACK_RTT_EMPTY;
12470 	rack->r_ctl.rack_rs.rs_rtt_cnt = 0;
12471 	rack->r_ctl.rack_rs.rs_rtt_tot = 0;
12472 }
12473 
12474 static void
12475 rack_set_pace_segments(struct tcpcb *tp, struct tcp_rack *rack, uint32_t line, uint64_t *fill_override)
12476 {
12477 	uint64_t bw_est, rate_wanted;
12478 	int chged = 0;
12479 	uint32_t user_max, orig_min, orig_max;
12480 
12481 	orig_min = rack->r_ctl.rc_pace_min_segs;
12482 	orig_max = rack->r_ctl.rc_pace_max_segs;
12483 	user_max = ctf_fixed_maxseg(tp) * rack->rc_user_set_max_segs;
12484 	if (ctf_fixed_maxseg(tp) != rack->r_ctl.rc_pace_min_segs)
12485 		chged = 1;
12486 	rack->r_ctl.rc_pace_min_segs = ctf_fixed_maxseg(tp);
12487 	if (rack->use_fixed_rate || rack->rc_force_max_seg) {
12488 		if (user_max != rack->r_ctl.rc_pace_max_segs)
12489 			chged = 1;
12490 	}
12491 	if (rack->rc_force_max_seg) {
12492 		rack->r_ctl.rc_pace_max_segs = user_max;
12493 	} else if (rack->use_fixed_rate) {
12494 		bw_est = rack_get_bw(rack);
12495 		if ((rack->r_ctl.crte == NULL) ||
12496 		    (bw_est != rack->r_ctl.crte->rate)) {
12497 			rack->r_ctl.rc_pace_max_segs = user_max;
12498 		} else {
12499 			/* We are pacing right at the hardware rate */
12500 			uint32_t segsiz;
12501 
12502 			segsiz = min(ctf_fixed_maxseg(tp),
12503 				     rack->r_ctl.rc_pace_min_segs);
12504 			rack->r_ctl.rc_pace_max_segs = tcp_get_pacing_burst_size(
12505 				                           tp, bw_est, segsiz, 0,
12506 							   rack->r_ctl.crte, NULL);
12507 		}
12508 	} else if (rack->rc_always_pace) {
12509 		if (rack->r_ctl.gp_bw ||
12510 #ifdef NETFLIX_PEAKRATE
12511 		    rack->rc_tp->t_maxpeakrate ||
12512 #endif
12513 		    rack->r_ctl.init_rate) {
12514 			/* We have a rate of some sort set */
12515 			uint32_t  orig;
12516 
12517 			bw_est = rack_get_bw(rack);
12518 			orig = rack->r_ctl.rc_pace_max_segs;
12519 			if (fill_override)
12520 				rate_wanted = *fill_override;
12521 			else
12522 				rate_wanted = rack_get_output_bw(rack, bw_est, NULL, NULL);
12523 			if (rate_wanted) {
12524 				/* We have something */
12525 				rack->r_ctl.rc_pace_max_segs = rack_get_pacing_len(rack,
12526 										   rate_wanted,
12527 										   ctf_fixed_maxseg(rack->rc_tp));
12528 			} else
12529 				rack->r_ctl.rc_pace_max_segs = rack->r_ctl.rc_pace_min_segs;
12530 			if (orig != rack->r_ctl.rc_pace_max_segs)
12531 				chged = 1;
12532 		} else if ((rack->r_ctl.gp_bw == 0) &&
12533 			   (rack->r_ctl.rc_pace_max_segs == 0)) {
12534 			/*
12535 			 * If we have nothing limit us to bursting
12536 			 * out IW sized pieces.
12537 			 */
12538 			chged = 1;
12539 			rack->r_ctl.rc_pace_max_segs = rc_init_window(rack);
12540 		}
12541 	}
12542 	if (rack->r_ctl.rc_pace_max_segs > PACE_MAX_IP_BYTES) {
12543 		chged = 1;
12544 		rack->r_ctl.rc_pace_max_segs = PACE_MAX_IP_BYTES;
12545 	}
12546 	if (chged)
12547 		rack_log_type_pacing_sizes(tp, rack, orig_min, orig_max, line, 2);
12548 }
12549 
12550 
12551 static void
12552 rack_init_fsb_block(struct tcpcb *tp, struct tcp_rack *rack)
12553 {
12554 #ifdef INET6
12555 	struct ip6_hdr *ip6 = NULL;
12556 #endif
12557 #ifdef INET
12558 	struct ip *ip = NULL;
12559 #endif
12560 	struct udphdr *udp = NULL;
12561 
12562 	/* Ok lets fill in the fast block, it can only be used with no IP options! */
12563 #ifdef INET6
12564 	if (rack->r_is_v6) {
12565 		rack->r_ctl.fsb.tcp_ip_hdr_len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
12566 		ip6 = (struct ip6_hdr *)rack->r_ctl.fsb.tcp_ip_hdr;
12567 		if (tp->t_port) {
12568 			rack->r_ctl.fsb.tcp_ip_hdr_len += sizeof(struct udphdr);
12569 			udp = (struct udphdr *)((caddr_t)ip6 + sizeof(struct ip6_hdr));
12570 			udp->uh_sport = htons(V_tcp_udp_tunneling_port);
12571 			udp->uh_dport = tp->t_port;
12572 			rack->r_ctl.fsb.udp = udp;
12573 			rack->r_ctl.fsb.th = (struct tcphdr *)(udp + 1);
12574 		} else
12575 		{
12576 			rack->r_ctl.fsb.th = (struct tcphdr *)(ip6 + 1);
12577 			rack->r_ctl.fsb.udp = NULL;
12578 		}
12579 		tcpip_fillheaders(rack->rc_inp,
12580 				  tp->t_port,
12581 				  ip6, rack->r_ctl.fsb.th);
12582 	} else
12583 #endif				/* INET6 */
12584 	{
12585 		rack->r_ctl.fsb.tcp_ip_hdr_len = sizeof(struct tcpiphdr);
12586 		ip = (struct ip *)rack->r_ctl.fsb.tcp_ip_hdr;
12587 		if (tp->t_port) {
12588 			rack->r_ctl.fsb.tcp_ip_hdr_len += sizeof(struct udphdr);
12589 			udp = (struct udphdr *)((caddr_t)ip + sizeof(struct ip));
12590 			udp->uh_sport = htons(V_tcp_udp_tunneling_port);
12591 			udp->uh_dport = tp->t_port;
12592 			rack->r_ctl.fsb.udp = udp;
12593 			rack->r_ctl.fsb.th = (struct tcphdr *)(udp + 1);
12594 		} else
12595 		{
12596 			rack->r_ctl.fsb.udp = NULL;
12597 			rack->r_ctl.fsb.th = (struct tcphdr *)(ip + 1);
12598 		}
12599 		tcpip_fillheaders(rack->rc_inp,
12600 				  tp->t_port,
12601 				  ip, rack->r_ctl.fsb.th);
12602 	}
12603 	rack->r_fsb_inited = 1;
12604 }
12605 
12606 static int
12607 rack_init_fsb(struct tcpcb *tp, struct tcp_rack *rack)
12608 {
12609 	/*
12610 	 * Allocate the larger of spaces V6 if available else just
12611 	 * V4 and include udphdr (overbook)
12612 	 */
12613 #ifdef INET6
12614 	rack->r_ctl.fsb.tcp_ip_hdr_len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + sizeof(struct udphdr);
12615 #else
12616 	rack->r_ctl.fsb.tcp_ip_hdr_len = sizeof(struct tcpiphdr) + sizeof(struct udphdr);
12617 #endif
12618 	rack->r_ctl.fsb.tcp_ip_hdr = malloc(rack->r_ctl.fsb.tcp_ip_hdr_len,
12619 					    M_TCPFSB, M_NOWAIT|M_ZERO);
12620 	if (rack->r_ctl.fsb.tcp_ip_hdr == NULL) {
12621 		return (ENOMEM);
12622 	}
12623 	rack->r_fsb_inited = 0;
12624 	return (0);
12625 }
12626 
12627 static int
12628 rack_init(struct tcpcb *tp)
12629 {
12630 	struct tcp_rack *rack = NULL;
12631 	struct rack_sendmap *insret;
12632 	uint32_t iwin, snt, us_cts;
12633 	int err;
12634 
12635 	tp->t_fb_ptr = uma_zalloc(rack_pcb_zone, M_NOWAIT);
12636 	if (tp->t_fb_ptr == NULL) {
12637 		/*
12638 		 * We need to allocate memory but cant. The INP and INP_INFO
12639 		 * locks and they are recusive (happens during setup. So a
12640 		 * scheme to drop the locks fails :(
12641 		 *
12642 		 */
12643 		return (ENOMEM);
12644 	}
12645 	memset(tp->t_fb_ptr, 0, sizeof(struct tcp_rack));
12646 
12647 	rack = (struct tcp_rack *)tp->t_fb_ptr;
12648 	RB_INIT(&rack->r_ctl.rc_mtree);
12649 	TAILQ_INIT(&rack->r_ctl.rc_free);
12650 	TAILQ_INIT(&rack->r_ctl.rc_tmap);
12651 	rack->rc_tp = tp;
12652 	rack->rc_inp = tp->t_inpcb;
12653 	/* Set the flag */
12654 	rack->r_is_v6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0;
12655 	/* Probably not needed but lets be sure */
12656 	rack_clear_rate_sample(rack);
12657 	/*
12658 	 * Save off the default values, socket options will poke
12659 	 * at these if pacing is not on or we have not yet
12660 	 * reached where pacing is on (gp_ready/fixed enabled).
12661 	 * When they get set into the CC module (when gp_ready
12662 	 * is enabled or we enable fixed) then we will set these
12663 	 * values into the CC and place in here the old values
12664 	 * so we have a restoral. Then we will set the flag
12665 	 * rc_pacing_cc_set. That way whenever we turn off pacing
12666 	 * or switch off this stack, we will know to go restore
12667 	 * the saved values.
12668 	 */
12669 	rack->r_ctl.rc_saved_beta.beta = V_newreno_beta_ecn;
12670 	rack->r_ctl.rc_saved_beta.beta_ecn = V_newreno_beta_ecn;
12671 	/* We want abe like behavior as well */
12672 	rack->r_ctl.rc_saved_beta.newreno_flags |= CC_NEWRENO_BETA_ECN_ENABLED;
12673 	rack->r_ctl.rc_reorder_fade = rack_reorder_fade;
12674 	rack->rc_allow_data_af_clo = rack_ignore_data_after_close;
12675 	rack->r_ctl.rc_tlp_threshold = rack_tlp_thresh;
12676 	rack->r_ctl.roundends = tp->snd_max;
12677 	if (use_rack_rr)
12678 		rack->use_rack_rr = 1;
12679 	if (V_tcp_delack_enabled)
12680 		tp->t_delayed_ack = 1;
12681 	else
12682 		tp->t_delayed_ack = 0;
12683 #ifdef TCP_ACCOUNTING
12684 	if (rack_tcp_accounting) {
12685 		tp->t_flags2 |= TF2_TCP_ACCOUNTING;
12686 	}
12687 #endif
12688 	if (rack_enable_shared_cwnd)
12689 		rack->rack_enable_scwnd = 1;
12690 	rack->rc_user_set_max_segs = rack_hptsi_segments;
12691 	rack->rc_force_max_seg = 0;
12692 	if (rack_use_imac_dack)
12693 		rack->rc_dack_mode = 1;
12694 	TAILQ_INIT(&rack->r_ctl.opt_list);
12695 	rack->r_ctl.rc_reorder_shift = rack_reorder_thresh;
12696 	rack->r_ctl.rc_pkt_delay = rack_pkt_delay;
12697 	rack->r_ctl.rc_tlp_cwnd_reduce = rack_lower_cwnd_at_tlp;
12698 	rack->r_ctl.rc_lowest_us_rtt = 0xffffffff;
12699 	rack->r_ctl.rc_highest_us_rtt = 0;
12700 	rack->r_ctl.bw_rate_cap = rack_bw_rate_cap;
12701 	rack->r_ctl.timer_slop = TICKS_2_USEC(tcp_rexmit_slop);
12702 	if (rack_use_cmp_acks)
12703 		rack->r_use_cmp_ack = 1;
12704 	if (rack_disable_prr)
12705 		rack->rack_no_prr = 1;
12706 	if (rack_gp_no_rec_chg)
12707 		rack->rc_gp_no_rec_chg = 1;
12708 	if (rack_pace_every_seg && tcp_can_enable_pacing()) {
12709 		rack->rc_always_pace = 1;
12710 		if (rack->use_fixed_rate || rack->gp_ready)
12711 			rack_set_cc_pacing(rack);
12712 	} else
12713 		rack->rc_always_pace = 0;
12714 	if (rack_enable_mqueue_for_nonpaced || rack->r_use_cmp_ack)
12715 		rack->r_mbuf_queue = 1;
12716 	else
12717 		rack->r_mbuf_queue = 0;
12718 	if  (rack->r_mbuf_queue || rack->rc_always_pace || rack->r_use_cmp_ack)
12719 		tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
12720 	else
12721 		tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
12722 	rack_set_pace_segments(tp, rack, __LINE__, NULL);
12723 	if (rack_limits_scwnd)
12724 		rack->r_limit_scw = 1;
12725 	else
12726 		rack->r_limit_scw = 0;
12727 	rack->rc_labc = V_tcp_abc_l_var;
12728 	rack->r_ctl.rc_high_rwnd = tp->snd_wnd;
12729 	rack->r_ctl.cwnd_to_use = tp->snd_cwnd;
12730 	rack->r_ctl.rc_rate_sample_method = rack_rate_sample_method;
12731 	rack->rack_tlp_threshold_use = rack_tlp_threshold_use;
12732 	rack->r_ctl.rc_prr_sendalot = rack_send_a_lot_in_prr;
12733 	rack->r_ctl.rc_min_to = rack_min_to;
12734 	microuptime(&rack->r_ctl.act_rcv_time);
12735 	rack->r_ctl.rc_last_time_decay = rack->r_ctl.act_rcv_time;
12736 	rack->r_running_late = 0;
12737 	rack->r_running_early = 0;
12738 	rack->rc_init_win = rack_default_init_window;
12739 	rack->r_ctl.rack_per_of_gp_ss = rack_per_of_gp_ss;
12740 	if (rack_hw_up_only)
12741 		rack->r_up_only = 1;
12742 	if (rack_do_dyn_mul) {
12743 		/* When dynamic adjustment is on CA needs to start at 100% */
12744 		rack->rc_gp_dyn_mul = 1;
12745 		if (rack_do_dyn_mul >= 100)
12746 			rack->r_ctl.rack_per_of_gp_ca = rack_do_dyn_mul;
12747 	} else
12748 		rack->r_ctl.rack_per_of_gp_ca = rack_per_of_gp_ca;
12749 	rack->r_ctl.rack_per_of_gp_rec = rack_per_of_gp_rec;
12750 	rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt;
12751 	rack->r_ctl.rc_tlp_rxt_last_time = tcp_tv_to_mssectick(&rack->r_ctl.act_rcv_time);
12752 	setup_time_filter_small(&rack->r_ctl.rc_gp_min_rtt, FILTER_TYPE_MIN,
12753 				rack_probertt_filter_life);
12754 	us_cts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
12755 	rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
12756 	rack->r_ctl.rc_time_of_last_probertt = us_cts;
12757 	rack->r_ctl.challenge_ack_ts = tcp_ts_getticks();
12758 	rack->r_ctl.rc_time_probertt_starts = 0;
12759 	if (rack_dsack_std_based & 0x1) {
12760 		/* Basically this means all rack timers are at least (srtt + 1/4 srtt) */
12761 		rack->rc_rack_tmr_std_based = 1;
12762 	}
12763 	if (rack_dsack_std_based & 0x2) {
12764 		/* Basically this means  rack timers are extended based on dsack by up to (2 * srtt) */
12765 		rack->rc_rack_use_dsack = 1;
12766 	}
12767 	/* We require at least one measurement, even if the sysctl is 0 */
12768 	if (rack_req_measurements)
12769 		rack->r_ctl.req_measurements = rack_req_measurements;
12770 	else
12771 		rack->r_ctl.req_measurements = 1;
12772 	if (rack_enable_hw_pacing)
12773 		rack->rack_hdw_pace_ena = 1;
12774 	if (rack_hw_rate_caps)
12775 		rack->r_rack_hw_rate_caps = 1;
12776 	/* Do we force on detection? */
12777 #ifdef NETFLIX_EXP_DETECTION
12778 	if (tcp_force_detection)
12779 		rack->do_detection = 1;
12780 	else
12781 #endif
12782 		rack->do_detection = 0;
12783 	if (rack_non_rxt_use_cr)
12784 		rack->rack_rec_nonrxt_use_cr = 1;
12785 	err = rack_init_fsb(tp, rack);
12786 	if (err) {
12787 		uma_zfree(rack_pcb_zone, tp->t_fb_ptr);
12788 		tp->t_fb_ptr = NULL;
12789 		return (err);
12790 	}
12791 	if (tp->snd_una != tp->snd_max) {
12792 		/* Create a send map for the current outstanding data */
12793 		struct rack_sendmap *rsm;
12794 
12795 		rsm = rack_alloc(rack);
12796 		if (rsm == NULL) {
12797 			uma_zfree(rack_pcb_zone, tp->t_fb_ptr);
12798 			tp->t_fb_ptr = NULL;
12799 			return (ENOMEM);
12800 		}
12801 		rsm->r_no_rtt_allowed = 1;
12802 		rsm->r_tim_lastsent[0] = rack_to_usec_ts(&rack->r_ctl.act_rcv_time);
12803 		rsm->r_rtr_cnt = 1;
12804 		rsm->r_rtr_bytes = 0;
12805 		if (tp->t_flags & TF_SENTFIN) {
12806 			rsm->r_end = tp->snd_max - 1;
12807 			rsm->r_flags |= RACK_HAS_FIN;
12808 		} else {
12809 			rsm->r_end = tp->snd_max;
12810 		}
12811 		if (tp->snd_una == tp->iss) {
12812 			/* The data space is one beyond snd_una */
12813 			rsm->r_flags |= RACK_HAS_SYN;
12814 			rsm->r_start = tp->iss;
12815 			rsm->r_end = rsm->r_start + (tp->snd_max - tp->snd_una);
12816 		} else
12817 			rsm->r_start = tp->snd_una;
12818 		rsm->r_dupack = 0;
12819 		if (rack->rc_inp->inp_socket->so_snd.sb_mb != NULL) {
12820 			rsm->m = sbsndmbuf(&rack->rc_inp->inp_socket->so_snd, 0, &rsm->soff);
12821 			if (rsm->m)
12822 				rsm->orig_m_len = rsm->m->m_len;
12823 			else
12824 				rsm->orig_m_len = 0;
12825 		} else {
12826 			/*
12827 			 * This can happen if we have a stand-alone FIN or
12828 			 *  SYN.
12829 			 */
12830 			rsm->m = NULL;
12831 			rsm->orig_m_len = 0;
12832 			rsm->soff = 0;
12833 		}
12834 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
12835 #ifdef INVARIANTS
12836 		if (insret != NULL) {
12837 			panic("Insert in rb tree fails ret:%p rack:%p rsm:%p",
12838 			      insret, rack, rsm);
12839 		}
12840 #endif
12841 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext);
12842 		rsm->r_in_tmap = 1;
12843 	}
12844 	/*
12845 	 * Timers in Rack are kept in microseconds so lets
12846 	 * convert any initial incoming variables
12847 	 * from ticks into usecs. Note that we
12848 	 * also change the values of t_srtt and t_rttvar, if
12849 	 * they are non-zero. They are kept with a 5
12850 	 * bit decimal so we have to carefully convert
12851 	 * these to get the full precision.
12852 	 */
12853 	rack_convert_rtts(tp);
12854 	tp->t_rttlow = TICKS_2_USEC(tp->t_rttlow);
12855 	if (rack_do_hystart) {
12856 		struct sockopt sopt;
12857 		struct cc_newreno_opts opt;
12858 
12859 		sopt.sopt_valsize = sizeof(struct cc_newreno_opts);
12860 		sopt.sopt_dir = SOPT_SET;
12861 		opt.name = CC_NEWRENO_ENABLE_HYSTART;
12862 		opt.val = rack_do_hystart;
12863 		if (CC_ALGO(tp)->ctl_output != NULL)
12864 			(void)CC_ALGO(tp)->ctl_output(tp->ccv, &sopt, &opt);
12865 	}
12866 	if (rack_def_profile)
12867 		rack_set_profile(rack, rack_def_profile);
12868 	/* Cancel the GP measurement in progress */
12869 	tp->t_flags &= ~TF_GPUTINPROG;
12870 	if (SEQ_GT(tp->snd_max, tp->iss))
12871 		snt = tp->snd_max - tp->iss;
12872 	else
12873 		snt = 0;
12874 	iwin = rc_init_window(rack);
12875 	if (snt < iwin) {
12876 		/* We are not past the initial window
12877 		 * so we need to make sure cwnd is
12878 		 * correct.
12879 		 */
12880 		if (tp->snd_cwnd < iwin)
12881 			tp->snd_cwnd = iwin;
12882 		/*
12883 		 * If we are within the initial window
12884 		 * we want ssthresh to be unlimited. Setting
12885 		 * it to the rwnd (which the default stack does
12886 		 * and older racks) is not really a good idea
12887 		 * since we want to be in SS and grow both the
12888 		 * cwnd and the rwnd (via dynamic rwnd growth). If
12889 		 * we set it to the rwnd then as the peer grows its
12890 		 * rwnd we will be stuck in CA and never hit SS.
12891 		 *
12892 		 * Its far better to raise it up high (this takes the
12893 		 * risk that there as been a loss already, probably
12894 		 * we should have an indicator in all stacks of loss
12895 		 * but we don't), but considering the normal use this
12896 		 * is a risk worth taking. The consequences of not
12897 		 * hitting SS are far worse than going one more time
12898 		 * into it early on (before we have sent even a IW).
12899 		 * It is highly unlikely that we will have had a loss
12900 		 * before getting the IW out.
12901 		 */
12902 		tp->snd_ssthresh = 0xffffffff;
12903 	}
12904 	rack_stop_all_timers(tp);
12905 	/* Lets setup the fsb block */
12906 	rack_start_hpts_timer(rack, tp, tcp_get_usecs(NULL), 0, 0, 0);
12907 	rack_log_rtt_shrinks(rack,  us_cts,  tp->t_rxtcur,
12908 			     __LINE__, RACK_RTTS_INIT);
12909 	return (0);
12910 }
12911 
12912 static int
12913 rack_handoff_ok(struct tcpcb *tp)
12914 {
12915 	if ((tp->t_state == TCPS_CLOSED) ||
12916 	    (tp->t_state == TCPS_LISTEN)) {
12917 		/* Sure no problem though it may not stick */
12918 		return (0);
12919 	}
12920 	if ((tp->t_state == TCPS_SYN_SENT) ||
12921 	    (tp->t_state == TCPS_SYN_RECEIVED)) {
12922 		/*
12923 		 * We really don't know if you support sack,
12924 		 * you have to get to ESTAB or beyond to tell.
12925 		 */
12926 		return (EAGAIN);
12927 	}
12928 	if ((tp->t_flags & TF_SENTFIN) && ((tp->snd_max - tp->snd_una) > 1)) {
12929 		/*
12930 		 * Rack will only send a FIN after all data is acknowledged.
12931 		 * So in this case we have more data outstanding. We can't
12932 		 * switch stacks until either all data and only the FIN
12933 		 * is left (in which case rack_init() now knows how
12934 		 * to deal with that) <or> all is acknowledged and we
12935 		 * are only left with incoming data, though why you
12936 		 * would want to switch to rack after all data is acknowledged
12937 		 * I have no idea (rrs)!
12938 		 */
12939 		return (EAGAIN);
12940 	}
12941 	if ((tp->t_flags & TF_SACK_PERMIT) || rack_sack_not_required){
12942 		return (0);
12943 	}
12944 	/*
12945 	 * If we reach here we don't do SACK on this connection so we can
12946 	 * never do rack.
12947 	 */
12948 	return (EINVAL);
12949 }
12950 
12951 
12952 static void
12953 rack_fini(struct tcpcb *tp, int32_t tcb_is_purged)
12954 {
12955 	int ack_cmp = 0;
12956 
12957 	if (tp->t_fb_ptr) {
12958 		struct tcp_rack *rack;
12959 		struct rack_sendmap *rsm, *nrsm, *rm;
12960 
12961 		rack = (struct tcp_rack *)tp->t_fb_ptr;
12962 		if (tp->t_in_pkt) {
12963 			/*
12964 			 * It is unsafe to process the packets since a
12965 			 * reset may be lurking in them (its rare but it
12966 			 * can occur). If we were to find a RST, then we
12967 			 * would end up dropping the connection and the
12968 			 * INP lock, so when we return the caller (tcp_usrreq)
12969 			 * will blow up when it trys to unlock the inp.
12970 			 */
12971 			struct mbuf *save, *m;
12972 
12973 			m = tp->t_in_pkt;
12974 			tp->t_in_pkt = NULL;
12975 			tp->t_tail_pkt = NULL;
12976 			while (m) {
12977 				save = m->m_nextpkt;
12978 				m->m_nextpkt = NULL;
12979 				m_freem(m);
12980 				m = save;
12981 			}
12982 			if ((tp->t_inpcb) &&
12983 			    (tp->t_inpcb->inp_flags2 & INP_MBUF_ACKCMP))
12984 				ack_cmp = 1;
12985 			if (ack_cmp) {
12986 				/* Total if we used large or small (if ack-cmp was used). */
12987 				if (rack->rc_inp->inp_flags2 & INP_MBUF_L_ACKS)
12988 					counter_u64_add(rack_large_ackcmp, 1);
12989 				else
12990 					counter_u64_add(rack_small_ackcmp, 1);
12991 			}
12992 		}
12993 		tp->t_flags &= ~TF_FORCEDATA;
12994 #ifdef NETFLIX_SHARED_CWND
12995 		if (rack->r_ctl.rc_scw) {
12996 			uint32_t limit;
12997 
12998 			if (rack->r_limit_scw)
12999 				limit = max(1, rack->r_ctl.rc_lowest_us_rtt);
13000 			else
13001 				limit = 0;
13002 			tcp_shared_cwnd_free_full(tp, rack->r_ctl.rc_scw,
13003 						  rack->r_ctl.rc_scw_index,
13004 						  limit);
13005 			rack->r_ctl.rc_scw = NULL;
13006 		}
13007 #endif
13008 		if (rack->r_ctl.fsb.tcp_ip_hdr) {
13009 			free(rack->r_ctl.fsb.tcp_ip_hdr, M_TCPFSB);
13010 			rack->r_ctl.fsb.tcp_ip_hdr = NULL;
13011 			rack->r_ctl.fsb.th = NULL;
13012 		}
13013 		/* Convert back to ticks, with  */
13014 		if (tp->t_srtt > 1) {
13015 			uint32_t val, frac;
13016 
13017 			val = USEC_2_TICKS(tp->t_srtt);
13018 			frac = tp->t_srtt % (HPTS_USEC_IN_SEC / hz);
13019 			tp->t_srtt = val << TCP_RTT_SHIFT;
13020 			/*
13021 			 * frac is the fractional part here is left
13022 			 * over from converting to hz and shifting.
13023 			 * We need to convert this to the 5 bit
13024 			 * remainder.
13025 			 */
13026 			if (frac) {
13027 				if (hz == 1000) {
13028 					frac = (((uint64_t)frac *  (uint64_t)TCP_RTT_SCALE) / (uint64_t)HPTS_USEC_IN_MSEC);
13029 				} else {
13030 					frac = (((uint64_t)frac * (uint64_t)(hz) * (uint64_t)TCP_RTT_SCALE) /(uint64_t)HPTS_USEC_IN_SEC);
13031 				}
13032 				tp->t_srtt += frac;
13033 			}
13034 		}
13035 		if (tp->t_rttvar) {
13036 			uint32_t val, frac;
13037 
13038 			val = USEC_2_TICKS(tp->t_rttvar);
13039 			frac = tp->t_srtt % (HPTS_USEC_IN_SEC / hz);
13040 			tp->t_rttvar = val <<  TCP_RTTVAR_SHIFT;
13041 			/*
13042 			 * frac is the fractional part here is left
13043 			 * over from converting to hz and shifting.
13044 			 * We need to convert this to the 5 bit
13045 			 * remainder.
13046 			 */
13047 			if (frac) {
13048 				if (hz == 1000) {
13049 					frac = (((uint64_t)frac *  (uint64_t)TCP_RTT_SCALE) / (uint64_t)HPTS_USEC_IN_MSEC);
13050 				} else {
13051 					frac = (((uint64_t)frac * (uint64_t)(hz) * (uint64_t)TCP_RTT_SCALE) /(uint64_t)HPTS_USEC_IN_SEC);
13052 				}
13053 				tp->t_rttvar += frac;
13054 			}
13055 		}
13056 		tp->t_rxtcur = USEC_2_TICKS(tp->t_rxtcur);
13057 		tp->t_rttlow = USEC_2_TICKS(tp->t_rttlow);
13058 		if (rack->rc_always_pace) {
13059 			tcp_decrement_paced_conn();
13060 			rack_undo_cc_pacing(rack);
13061 			rack->rc_always_pace = 0;
13062 		}
13063 		/* Clean up any options if they were not applied */
13064 		while (!TAILQ_EMPTY(&rack->r_ctl.opt_list)) {
13065 			struct deferred_opt_list *dol;
13066 
13067 			dol = TAILQ_FIRST(&rack->r_ctl.opt_list);
13068 			TAILQ_REMOVE(&rack->r_ctl.opt_list, dol, next);
13069 			free(dol, M_TCPDO);
13070 		}
13071 		/* rack does not use force data but other stacks may clear it */
13072 		if (rack->r_ctl.crte != NULL) {
13073 			tcp_rel_pacing_rate(rack->r_ctl.crte, tp);
13074 			rack->rack_hdrw_pacing = 0;
13075 			rack->r_ctl.crte = NULL;
13076 		}
13077 #ifdef TCP_BLACKBOX
13078 		tcp_log_flowend(tp);
13079 #endif
13080 		RB_FOREACH_SAFE(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm) {
13081 			rm = RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
13082 #ifdef INVARIANTS
13083 			if (rm != rsm) {
13084 				panic("At fini, rack:%p rsm:%p rm:%p",
13085 				      rack, rsm, rm);
13086 			}
13087 #endif
13088 			uma_zfree(rack_zone, rsm);
13089 		}
13090 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
13091 		while (rsm) {
13092 			TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_tnext);
13093 			uma_zfree(rack_zone, rsm);
13094 			rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
13095 		}
13096 		rack->rc_free_cnt = 0;
13097 		uma_zfree(rack_pcb_zone, tp->t_fb_ptr);
13098 		tp->t_fb_ptr = NULL;
13099 	}
13100 	if (tp->t_inpcb) {
13101 		tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
13102 		tp->t_inpcb->inp_flags2 &= ~INP_MBUF_QUEUE_READY;
13103 		tp->t_inpcb->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
13104 		tp->t_inpcb->inp_flags2 &= ~INP_MBUF_ACKCMP;
13105 		/* Cancel the GP measurement in progress */
13106 		tp->t_flags &= ~TF_GPUTINPROG;
13107 		tp->t_inpcb->inp_flags2 &= ~INP_MBUF_L_ACKS;
13108 	}
13109 	/* Make sure snd_nxt is correctly set */
13110 	tp->snd_nxt = tp->snd_max;
13111 }
13112 
13113 static void
13114 rack_set_state(struct tcpcb *tp, struct tcp_rack *rack)
13115 {
13116 	if ((rack->r_state == TCPS_CLOSED) && (tp->t_state != TCPS_CLOSED)) {
13117 		rack->r_is_v6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0;
13118 	}
13119 	switch (tp->t_state) {
13120 	case TCPS_SYN_SENT:
13121 		rack->r_state = TCPS_SYN_SENT;
13122 		rack->r_substate = rack_do_syn_sent;
13123 		break;
13124 	case TCPS_SYN_RECEIVED:
13125 		rack->r_state = TCPS_SYN_RECEIVED;
13126 		rack->r_substate = rack_do_syn_recv;
13127 		break;
13128 	case TCPS_ESTABLISHED:
13129 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
13130 		rack->r_state = TCPS_ESTABLISHED;
13131 		rack->r_substate = rack_do_established;
13132 		break;
13133 	case TCPS_CLOSE_WAIT:
13134 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
13135 		rack->r_state = TCPS_CLOSE_WAIT;
13136 		rack->r_substate = rack_do_close_wait;
13137 		break;
13138 	case TCPS_FIN_WAIT_1:
13139 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
13140 		rack->r_state = TCPS_FIN_WAIT_1;
13141 		rack->r_substate = rack_do_fin_wait_1;
13142 		break;
13143 	case TCPS_CLOSING:
13144 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
13145 		rack->r_state = TCPS_CLOSING;
13146 		rack->r_substate = rack_do_closing;
13147 		break;
13148 	case TCPS_LAST_ACK:
13149 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
13150 		rack->r_state = TCPS_LAST_ACK;
13151 		rack->r_substate = rack_do_lastack;
13152 		break;
13153 	case TCPS_FIN_WAIT_2:
13154 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
13155 		rack->r_state = TCPS_FIN_WAIT_2;
13156 		rack->r_substate = rack_do_fin_wait_2;
13157 		break;
13158 	case TCPS_LISTEN:
13159 	case TCPS_CLOSED:
13160 	case TCPS_TIME_WAIT:
13161 	default:
13162 		break;
13163 	};
13164 	if (rack->r_use_cmp_ack && TCPS_HAVEESTABLISHED(tp->t_state))
13165 		rack->rc_inp->inp_flags2 |= INP_MBUF_ACKCMP;
13166 
13167 }
13168 
13169 static void
13170 rack_timer_audit(struct tcpcb *tp, struct tcp_rack *rack, struct sockbuf *sb)
13171 {
13172 	/*
13173 	 * We received an ack, and then did not
13174 	 * call send or were bounced out due to the
13175 	 * hpts was running. Now a timer is up as well, is
13176 	 * it the right timer?
13177 	 */
13178 	struct rack_sendmap *rsm;
13179 	int tmr_up;
13180 
13181 	tmr_up = rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK;
13182 	if (rack->rc_in_persist && (tmr_up == PACE_TMR_PERSIT))
13183 		return;
13184 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
13185 	if (((rsm == NULL) || (tp->t_state < TCPS_ESTABLISHED)) &&
13186 	    (tmr_up == PACE_TMR_RXT)) {
13187 		/* Should be an RXT */
13188 		return;
13189 	}
13190 	if (rsm == NULL) {
13191 		/* Nothing outstanding? */
13192 		if (tp->t_flags & TF_DELACK) {
13193 			if (tmr_up == PACE_TMR_DELACK)
13194 				/* We are supposed to have delayed ack up and we do */
13195 				return;
13196 		} else if (sbavail(&tp->t_inpcb->inp_socket->so_snd) && (tmr_up == PACE_TMR_RXT)) {
13197 			/*
13198 			 * if we hit enobufs then we would expect the possiblity
13199 			 * of nothing outstanding and the RXT up (and the hptsi timer).
13200 			 */
13201 			return;
13202 		} else if (((V_tcp_always_keepalive ||
13203 			     rack->rc_inp->inp_socket->so_options & SO_KEEPALIVE) &&
13204 			    (tp->t_state <= TCPS_CLOSING)) &&
13205 			   (tmr_up == PACE_TMR_KEEP) &&
13206 			   (tp->snd_max == tp->snd_una)) {
13207 			/* We should have keep alive up and we do */
13208 			return;
13209 		}
13210 	}
13211 	if (SEQ_GT(tp->snd_max, tp->snd_una) &&
13212 		   ((tmr_up == PACE_TMR_TLP) ||
13213 		    (tmr_up == PACE_TMR_RACK) ||
13214 		    (tmr_up == PACE_TMR_RXT))) {
13215 		/*
13216 		 * Either a Rack, TLP or RXT is fine if  we
13217 		 * have outstanding data.
13218 		 */
13219 		return;
13220 	} else if (tmr_up == PACE_TMR_DELACK) {
13221 		/*
13222 		 * If the delayed ack was going to go off
13223 		 * before the rtx/tlp/rack timer were going to
13224 		 * expire, then that would be the timer in control.
13225 		 * Note we don't check the time here trusting the
13226 		 * code is correct.
13227 		 */
13228 		return;
13229 	}
13230 	/*
13231 	 * Ok the timer originally started is not what we want now.
13232 	 * We will force the hpts to be stopped if any, and restart
13233 	 * with the slot set to what was in the saved slot.
13234 	 */
13235 	if (tcp_in_hpts(rack->rc_inp)) {
13236 		if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
13237 			uint32_t us_cts;
13238 
13239 			us_cts = tcp_get_usecs(NULL);
13240 			if (TSTMP_GT(rack->r_ctl.rc_last_output_to, us_cts)) {
13241 				rack->r_early = 1;
13242 				rack->r_ctl.rc_agg_early += (rack->r_ctl.rc_last_output_to - us_cts);
13243 			}
13244 			rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
13245 		}
13246 		tcp_hpts_remove(tp->t_inpcb, HPTS_REMOVE_OUTPUT);
13247 	}
13248 	rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
13249 	rack_start_hpts_timer(rack, tp, tcp_get_usecs(NULL), 0, 0, 0);
13250 }
13251 
13252 
13253 static void
13254 rack_do_win_updates(struct tcpcb *tp, struct tcp_rack *rack, uint32_t tiwin, uint32_t seq, uint32_t ack, uint32_t cts, uint32_t high_seq)
13255 {
13256 	if ((SEQ_LT(tp->snd_wl1, seq) ||
13257 	    (tp->snd_wl1 == seq && (SEQ_LT(tp->snd_wl2, ack) ||
13258 	    (tp->snd_wl2 == ack && tiwin > tp->snd_wnd))))) {
13259 		/* keep track of pure window updates */
13260 		if ((tp->snd_wl2 == ack) && (tiwin > tp->snd_wnd))
13261 			KMOD_TCPSTAT_INC(tcps_rcvwinupd);
13262 		tp->snd_wnd = tiwin;
13263 		rack_validate_fo_sendwin_up(tp, rack);
13264 		tp->snd_wl1 = seq;
13265 		tp->snd_wl2 = ack;
13266 		if (tp->snd_wnd > tp->max_sndwnd)
13267 			tp->max_sndwnd = tp->snd_wnd;
13268 	    rack->r_wanted_output = 1;
13269 	} else if ((tp->snd_wl2 == ack) && (tiwin < tp->snd_wnd)) {
13270 		tp->snd_wnd = tiwin;
13271 		rack_validate_fo_sendwin_up(tp, rack);
13272 		tp->snd_wl1 = seq;
13273 		tp->snd_wl2 = ack;
13274 	} else {
13275 		/* Not a valid win update */
13276 		return;
13277 	}
13278 	if (tp->snd_wnd > tp->max_sndwnd)
13279 		tp->max_sndwnd = tp->snd_wnd;
13280 	if (tp->snd_wnd < (tp->snd_max - high_seq)) {
13281 		/* The peer collapsed the window */
13282 		rack_collapsed_window(rack);
13283 	} else if (rack->rc_has_collapsed)
13284 		rack_un_collapse_window(rack);
13285 	/* Do we exit persists? */
13286 	if ((rack->rc_in_persist != 0) &&
13287 	    (tp->snd_wnd >= min((rack->r_ctl.rc_high_rwnd/2),
13288 				rack->r_ctl.rc_pace_min_segs))) {
13289 		rack_exit_persist(tp, rack, cts);
13290 	}
13291 	/* Do we enter persists? */
13292 	if ((rack->rc_in_persist == 0) &&
13293 	    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), rack->r_ctl.rc_pace_min_segs)) &&
13294 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
13295 	    (tp->snd_max == tp->snd_una) &&
13296 	    sbavail(&tp->t_inpcb->inp_socket->so_snd) &&
13297 	    (sbavail(&tp->t_inpcb->inp_socket->so_snd) > tp->snd_wnd)) {
13298 		/*
13299 		 * Here the rwnd is less than
13300 		 * the pacing size, we are established,
13301 		 * nothing is outstanding, and there is
13302 		 * data to send. Enter persists.
13303 		 */
13304 		rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
13305 	}
13306 }
13307 
13308 static void
13309 rack_log_input_packet(struct tcpcb *tp, struct tcp_rack *rack, struct tcp_ackent *ae, int ackval, uint32_t high_seq)
13310 {
13311 
13312 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
13313 		union tcp_log_stackspecific log;
13314 		struct timeval ltv;
13315 		char tcp_hdr_buf[60];
13316 		struct tcphdr *th;
13317 		struct timespec ts;
13318 		uint32_t orig_snd_una;
13319 		uint8_t xx = 0;
13320 
13321 #ifdef NETFLIX_HTTP_LOGGING
13322 		struct http_sendfile_track *http_req;
13323 
13324 		if (SEQ_GT(ae->ack, tp->snd_una)) {
13325 			http_req = tcp_http_find_req_for_seq(tp, (ae->ack-1));
13326 		} else {
13327 			http_req = tcp_http_find_req_for_seq(tp, ae->ack);
13328 		}
13329 #endif
13330 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
13331 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
13332 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
13333 		if (rack->rack_no_prr == 0)
13334 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
13335 		else
13336 			log.u_bbr.flex1 = 0;
13337 		log.u_bbr.use_lt_bw = rack->r_ent_rec_ns;
13338 		log.u_bbr.use_lt_bw <<= 1;
13339 		log.u_bbr.use_lt_bw |= rack->r_might_revert;
13340 		log.u_bbr.flex2 = rack->r_ctl.rc_num_maps_alloced;
13341 		log.u_bbr.inflight = ctf_flight_size(tp, rack->r_ctl.rc_sacked);
13342 		log.u_bbr.pkts_out = tp->t_maxseg;
13343 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
13344 		log.u_bbr.flex7 = 1;
13345 		log.u_bbr.lost = ae->flags;
13346 		log.u_bbr.cwnd_gain = ackval;
13347 		log.u_bbr.pacing_gain = 0x2;
13348 		if (ae->flags & TSTMP_HDWR) {
13349 			/* Record the hardware timestamp if present */
13350 			log.u_bbr.flex3 = M_TSTMP;
13351 			ts.tv_sec = ae->timestamp / 1000000000;
13352 			ts.tv_nsec = ae->timestamp % 1000000000;
13353 			ltv.tv_sec = ts.tv_sec;
13354 			ltv.tv_usec = ts.tv_nsec / 1000;
13355 			log.u_bbr.lt_epoch = tcp_tv_to_usectick(&ltv);
13356 		} else if (ae->flags & TSTMP_LRO) {
13357 			/* Record the LRO the arrival timestamp */
13358 			log.u_bbr.flex3 = M_TSTMP_LRO;
13359 			ts.tv_sec = ae->timestamp / 1000000000;
13360 			ts.tv_nsec = ae->timestamp % 1000000000;
13361 			ltv.tv_sec = ts.tv_sec;
13362 			ltv.tv_usec = ts.tv_nsec / 1000;
13363 			log.u_bbr.flex5 = tcp_tv_to_usectick(&ltv);
13364 		}
13365 		log.u_bbr.timeStamp = tcp_get_usecs(&ltv);
13366 		/* Log the rcv time */
13367 		log.u_bbr.delRate = ae->timestamp;
13368 #ifdef NETFLIX_HTTP_LOGGING
13369 		log.u_bbr.applimited = tp->t_http_closed;
13370 		log.u_bbr.applimited <<= 8;
13371 		log.u_bbr.applimited |= tp->t_http_open;
13372 		log.u_bbr.applimited <<= 8;
13373 		log.u_bbr.applimited |= tp->t_http_req;
13374 		if (http_req) {
13375 			/* Copy out any client req info */
13376 			/* seconds */
13377 			log.u_bbr.pkt_epoch = (http_req->localtime / HPTS_USEC_IN_SEC);
13378 			/* useconds */
13379 			log.u_bbr.delivered = (http_req->localtime % HPTS_USEC_IN_SEC);
13380 			log.u_bbr.rttProp = http_req->timestamp;
13381 			log.u_bbr.cur_del_rate = http_req->start;
13382 			if (http_req->flags & TCP_HTTP_TRACK_FLG_OPEN) {
13383 				log.u_bbr.flex8 |= 1;
13384 			} else {
13385 				log.u_bbr.flex8 |= 2;
13386 				log.u_bbr.bw_inuse = http_req->end;
13387 			}
13388 			log.u_bbr.flex6 = http_req->start_seq;
13389 			if (http_req->flags & TCP_HTTP_TRACK_FLG_COMP) {
13390 				log.u_bbr.flex8 |= 4;
13391 				log.u_bbr.epoch = http_req->end_seq;
13392 			}
13393 		}
13394 #endif
13395 		memset(tcp_hdr_buf, 0, sizeof(tcp_hdr_buf));
13396 		th = (struct tcphdr *)tcp_hdr_buf;
13397 		th->th_seq = ae->seq;
13398 		th->th_ack = ae->ack;
13399 		th->th_win = ae->win;
13400 		/* Now fill in the ports */
13401 		th->th_sport = tp->t_inpcb->inp_fport;
13402 		th->th_dport = tp->t_inpcb->inp_lport;
13403 		th->th_flags = ae->flags & 0xff;
13404 		/* Now do we have a timestamp option? */
13405 		if (ae->flags & HAS_TSTMP) {
13406 			u_char *cp;
13407 			uint32_t val;
13408 
13409 			th->th_off = ((sizeof(struct tcphdr) + TCPOLEN_TSTAMP_APPA) >> 2);
13410 			cp = (u_char *)(th + 1);
13411 			*cp = TCPOPT_NOP;
13412 			cp++;
13413 			*cp = TCPOPT_NOP;
13414 			cp++;
13415 			*cp = TCPOPT_TIMESTAMP;
13416 			cp++;
13417 			*cp = TCPOLEN_TIMESTAMP;
13418 			cp++;
13419 			val = htonl(ae->ts_value);
13420 			bcopy((char *)&val,
13421 			      (char *)cp, sizeof(uint32_t));
13422 			val = htonl(ae->ts_echo);
13423 			bcopy((char *)&val,
13424 			      (char *)(cp + 4), sizeof(uint32_t));
13425 		} else
13426 			th->th_off = (sizeof(struct tcphdr) >> 2);
13427 
13428 		/*
13429 		 * For sane logging we need to play a little trick.
13430 		 * If the ack were fully processed we would have moved
13431 		 * snd_una to high_seq, but since compressed acks are
13432 		 * processed in two phases, at this point (logging) snd_una
13433 		 * won't be advanced. So we would see multiple acks showing
13434 		 * the advancement. We can prevent that by "pretending" that
13435 		 * snd_una was advanced and then un-advancing it so that the
13436 		 * logging code has the right value for tlb_snd_una.
13437 		 */
13438 		if (tp->snd_una != high_seq) {
13439 			orig_snd_una = tp->snd_una;
13440 			tp->snd_una = high_seq;
13441 			xx = 1;
13442 		} else
13443 			xx = 0;
13444 		TCP_LOG_EVENTP(tp, th,
13445 			       &tp->t_inpcb->inp_socket->so_rcv,
13446 			       &tp->t_inpcb->inp_socket->so_snd, TCP_LOG_IN, 0,
13447 			       0, &log, true, &ltv);
13448 		if (xx) {
13449 			tp->snd_una = orig_snd_una;
13450 		}
13451 	}
13452 
13453 }
13454 
13455 static void
13456 rack_handle_probe_response(struct tcp_rack *rack, uint32_t tiwin, uint32_t us_cts)
13457 {
13458 	uint32_t us_rtt;
13459 	/*
13460 	 * A persist or keep-alive was forced out, update our
13461 	 * min rtt time. Note now worry about lost responses.
13462 	 * When a subsequent keep-alive or persist times out
13463 	 * and forced_ack is still on, then the last probe
13464 	 * was not responded to. In such cases we have a
13465 	 * sysctl that controls the behavior. Either we apply
13466 	 * the rtt but with reduced confidence (0). Or we just
13467 	 * plain don't apply the rtt estimate. Having data flow
13468 	 * will clear the probe_not_answered flag i.e. cum-ack
13469 	 * move forward <or> exiting and reentering persists.
13470 	 */
13471 
13472 	rack->forced_ack = 0;
13473 	rack->rc_tp->t_rxtshift = 0;
13474 	if ((rack->rc_in_persist &&
13475 	     (tiwin == rack->rc_tp->snd_wnd)) ||
13476 	    (rack->rc_in_persist == 0)) {
13477 		/*
13478 		 * In persists only apply the RTT update if this is
13479 		 * a response to our window probe. And that
13480 		 * means the rwnd sent must match the current
13481 		 * snd_wnd. If it does not, then we got a
13482 		 * window update ack instead. For keepalive
13483 		 * we allow the answer no matter what the window.
13484 		 *
13485 		 * Note that if the probe_not_answered is set then
13486 		 * the forced_ack_ts is the oldest one i.e. the first
13487 		 * probe sent that might have been lost. This assures
13488 		 * us that if we do calculate an RTT it is longer not
13489 		 * some short thing.
13490 		 */
13491 		if (rack->rc_in_persist)
13492 			counter_u64_add(rack_persists_acks, 1);
13493 		us_rtt = us_cts - rack->r_ctl.forced_ack_ts;
13494 		if (us_rtt == 0)
13495 			us_rtt = 1;
13496 		if (rack->probe_not_answered == 0) {
13497 			rack_apply_updated_usrtt(rack, us_rtt, us_cts);
13498 			tcp_rack_xmit_timer(rack, us_rtt, 0, us_rtt, 3, NULL, 1);
13499 		} else {
13500 			/* We have a retransmitted probe here too */
13501 			if (rack_apply_rtt_with_reduced_conf) {
13502 				rack_apply_updated_usrtt(rack, us_rtt, us_cts);
13503 				tcp_rack_xmit_timer(rack, us_rtt, 0, us_rtt, 0, NULL, 1);
13504 			}
13505 		}
13506 	}
13507 }
13508 
13509 
13510 static int
13511 rack_do_compressed_ack_processing(struct tcpcb *tp, struct socket *so, struct mbuf *m, int nxt_pkt, struct timeval *tv)
13512 {
13513 	/*
13514 	 * Handle a "special" compressed ack mbuf. Each incoming
13515 	 * ack has only four possible dispositions:
13516 	 *
13517 	 * A) It moves the cum-ack forward
13518 	 * B) It is behind the cum-ack.
13519 	 * C) It is a window-update ack.
13520 	 * D) It is a dup-ack.
13521 	 *
13522 	 * Note that we can have between 1 -> TCP_COMP_ACK_ENTRIES
13523 	 * in the incoming mbuf. We also need to still pay attention
13524 	 * to nxt_pkt since there may be another packet after this
13525 	 * one.
13526 	 */
13527 #ifdef TCP_ACCOUNTING
13528 	uint64_t ts_val;
13529 	uint64_t rdstc;
13530 #endif
13531 	int segsiz;
13532 	struct timespec ts;
13533 	struct tcp_rack *rack;
13534 	struct tcp_ackent *ae;
13535 	uint32_t tiwin, ms_cts, cts, acked, acked_amount, high_seq, win_seq, the_win, win_upd_ack;
13536 	int cnt, i, did_out, ourfinisacked = 0;
13537 	struct tcpopt to_holder, *to = NULL;
13538 	int win_up_req = 0;
13539 	int nsegs = 0;
13540 	int under_pacing = 1;
13541 	int recovery = 0;
13542 	int idx;
13543 #ifdef TCP_ACCOUNTING
13544 	sched_pin();
13545 #endif
13546 	rack = (struct tcp_rack *)tp->t_fb_ptr;
13547 	if (rack->gp_ready &&
13548 	    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT))
13549 		under_pacing = 0;
13550 	else
13551 		under_pacing = 1;
13552 
13553 	if (rack->r_state != tp->t_state)
13554 		rack_set_state(tp, rack);
13555 	if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
13556 	    (tp->t_flags & TF_GPUTINPROG)) {
13557 		/*
13558 		 * We have a goodput in progress
13559 		 * and we have entered a late state.
13560 		 * Do we have enough data in the sb
13561 		 * to handle the GPUT request?
13562 		 */
13563 		uint32_t bytes;
13564 
13565 		bytes = tp->gput_ack - tp->gput_seq;
13566 		if (SEQ_GT(tp->gput_seq, tp->snd_una))
13567 			bytes += tp->gput_seq - tp->snd_una;
13568 		if (bytes > sbavail(&tp->t_inpcb->inp_socket->so_snd)) {
13569 			/*
13570 			 * There are not enough bytes in the socket
13571 			 * buffer that have been sent to cover this
13572 			 * measurement. Cancel it.
13573 			 */
13574 			rack_log_pacing_delay_calc(rack, (tp->gput_ack - tp->gput_seq) /*flex2*/,
13575 						   rack->r_ctl.rc_gp_srtt /*flex1*/,
13576 						   tp->gput_seq,
13577 						   0, 0, 18, __LINE__, NULL, 0);
13578 			tp->t_flags &= ~TF_GPUTINPROG;
13579 		}
13580 	}
13581 	to = &to_holder;
13582 	to->to_flags = 0;
13583 	KASSERT((m->m_len >= sizeof(struct tcp_ackent)),
13584 		("tp:%p m_cmpack:%p with invalid len:%u", tp, m, m->m_len));
13585 	cnt = m->m_len / sizeof(struct tcp_ackent);
13586 	idx = cnt / 5;
13587 	if (idx >= MAX_NUM_OF_CNTS)
13588 		idx = MAX_NUM_OF_CNTS - 1;
13589 	counter_u64_add(rack_proc_comp_ack[idx], 1);
13590 	counter_u64_add(rack_multi_single_eq, cnt);
13591 	high_seq = tp->snd_una;
13592 	the_win = tp->snd_wnd;
13593 	win_seq = tp->snd_wl1;
13594 	win_upd_ack = tp->snd_wl2;
13595 	cts = tcp_tv_to_usectick(tv);
13596 	ms_cts = tcp_tv_to_mssectick(tv);
13597 	segsiz = ctf_fixed_maxseg(tp);
13598 	if ((rack->rc_gp_dyn_mul) &&
13599 	    (rack->use_fixed_rate == 0) &&
13600 	    (rack->rc_always_pace)) {
13601 		/* Check in on probertt */
13602 		rack_check_probe_rtt(rack, cts);
13603 	}
13604 	for (i = 0; i < cnt; i++) {
13605 #ifdef TCP_ACCOUNTING
13606 		ts_val = get_cyclecount();
13607 #endif
13608 		rack_clear_rate_sample(rack);
13609 		ae = ((mtod(m, struct tcp_ackent *)) + i);
13610 		/* Setup the window */
13611 		tiwin = ae->win << tp->snd_scale;
13612 		/* figure out the type of ack */
13613 		if (SEQ_LT(ae->ack, high_seq)) {
13614 			/* Case B*/
13615 			ae->ack_val_set = ACK_BEHIND;
13616 		} else if (SEQ_GT(ae->ack, high_seq)) {
13617 			/* Case A */
13618 			ae->ack_val_set = ACK_CUMACK;
13619 		} else if ((tiwin == the_win) && (rack->rc_in_persist == 0)){
13620 			/* Case D */
13621 			ae->ack_val_set = ACK_DUPACK;
13622 		} else {
13623 			/* Case C */
13624 			ae->ack_val_set = ACK_RWND;
13625 		}
13626 		rack_log_input_packet(tp, rack, ae, ae->ack_val_set, high_seq);
13627 		/* Validate timestamp */
13628 		if (ae->flags & HAS_TSTMP) {
13629 			/* Setup for a timestamp */
13630 			to->to_flags = TOF_TS;
13631 			ae->ts_echo -= tp->ts_offset;
13632 			to->to_tsecr = ae->ts_echo;
13633 			to->to_tsval = ae->ts_value;
13634 			/*
13635 			 * If echoed timestamp is later than the current time, fall back to
13636 			 * non RFC1323 RTT calculation.  Normalize timestamp if syncookies
13637 			 * were used when this connection was established.
13638 			 */
13639 			if (TSTMP_GT(ae->ts_echo, ms_cts))
13640 				to->to_tsecr = 0;
13641 			if (tp->ts_recent &&
13642 			    TSTMP_LT(ae->ts_value, tp->ts_recent)) {
13643 				if (ctf_ts_check_ac(tp, (ae->flags & 0xff))) {
13644 #ifdef TCP_ACCOUNTING
13645 					rdstc = get_cyclecount();
13646 					if (rdstc > ts_val) {
13647 						counter_u64_add(tcp_proc_time[ae->ack_val_set] ,
13648 								(rdstc - ts_val));
13649 						if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13650 							tp->tcp_proc_time[ae->ack_val_set] += (rdstc - ts_val);
13651 						}
13652 					}
13653 #endif
13654 					continue;
13655 				}
13656 			}
13657 			if (SEQ_LEQ(ae->seq, tp->last_ack_sent) &&
13658 			    SEQ_LEQ(tp->last_ack_sent, ae->seq)) {
13659 				tp->ts_recent_age = tcp_ts_getticks();
13660 				tp->ts_recent = ae->ts_value;
13661 			}
13662 		} else {
13663 			/* Setup for a no options */
13664 			to->to_flags = 0;
13665 		}
13666 		/* Update the rcv time and perform idle reduction possibly */
13667 		if  (tp->t_idle_reduce &&
13668 		     (tp->snd_max == tp->snd_una) &&
13669 		     ((ticks - tp->t_rcvtime) >= tp->t_rxtcur)) {
13670 			counter_u64_add(rack_input_idle_reduces, 1);
13671 			rack_cc_after_idle(rack, tp);
13672 		}
13673 		tp->t_rcvtime = ticks;
13674 		/* Now what about ECN? */
13675 		if (tp->t_flags2 & TF2_ECN_PERMIT) {
13676 			if (ae->flags & TH_CWR) {
13677 				tp->t_flags2 &= ~TF2_ECN_SND_ECE;
13678 				tp->t_flags |= TF_ACKNOW;
13679 			}
13680 			switch (ae->codepoint & IPTOS_ECN_MASK) {
13681 			case IPTOS_ECN_CE:
13682 				tp->t_flags2 |= TF2_ECN_SND_ECE;
13683 				KMOD_TCPSTAT_INC(tcps_ecn_ce);
13684 				break;
13685 			case IPTOS_ECN_ECT0:
13686 				KMOD_TCPSTAT_INC(tcps_ecn_ect0);
13687 				break;
13688 			case IPTOS_ECN_ECT1:
13689 				KMOD_TCPSTAT_INC(tcps_ecn_ect1);
13690 				break;
13691 			}
13692 
13693 			/* Process a packet differently from RFC3168. */
13694 			cc_ecnpkt_handler_flags(tp, ae->flags, ae->codepoint);
13695 			/* Congestion experienced. */
13696 			if (ae->flags & TH_ECE) {
13697 				rack_cong_signal(tp,  CC_ECN, ae->ack);
13698 			}
13699 		}
13700 #ifdef TCP_ACCOUNTING
13701 		/* Count for the specific type of ack in */
13702 		counter_u64_add(tcp_cnt_counters[ae->ack_val_set], 1);
13703 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13704 			tp->tcp_cnt_counters[ae->ack_val_set]++;
13705 		}
13706 #endif
13707 		/*
13708 		 * Note how we could move up these in the determination
13709 		 * above, but we don't so that way the timestamp checks (and ECN)
13710 		 * is done first before we do any processing on the ACK.
13711 		 * The non-compressed path through the code has this
13712 		 * weakness (noted by @jtl) that it actually does some
13713 		 * processing before verifying the timestamp information.
13714 		 * We don't take that path here which is why we set
13715 		 * the ack_val_set first, do the timestamp and ecn
13716 		 * processing, and then look at what we have setup.
13717 		 */
13718 		if (ae->ack_val_set == ACK_BEHIND) {
13719 			/*
13720 			 * Case B flag reordering, if window is not closed
13721 			 * or it could be a keep-alive or persists
13722 			 */
13723 			if (SEQ_LT(ae->ack, tp->snd_una) && (sbspace(&so->so_rcv) > segsiz)) {
13724 				counter_u64_add(rack_reorder_seen, 1);
13725 				rack->r_ctl.rc_reorder_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
13726 			}
13727 		} else if (ae->ack_val_set == ACK_DUPACK) {
13728 			/* Case D */
13729 			rack_strike_dupack(rack);
13730 		} else if (ae->ack_val_set == ACK_RWND) {
13731 			/* Case C */
13732 			if ((ae->flags & TSTMP_LRO) || (ae->flags & TSTMP_HDWR)) {
13733 				ts.tv_sec = ae->timestamp / 1000000000;
13734 				ts.tv_nsec = ae->timestamp % 1000000000;
13735 				rack->r_ctl.act_rcv_time.tv_sec = ts.tv_sec;
13736 				rack->r_ctl.act_rcv_time.tv_usec = ts.tv_nsec/1000;
13737 			} else {
13738 				rack->r_ctl.act_rcv_time = *tv;
13739 			}
13740 			if (rack->forced_ack) {
13741 				rack_handle_probe_response(rack, tiwin,
13742 							   tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time));
13743 			}
13744 			win_up_req = 1;
13745 			win_upd_ack = ae->ack;
13746 			win_seq = ae->seq;
13747 			the_win = tiwin;
13748 			rack_do_win_updates(tp, rack, the_win, win_seq, win_upd_ack, cts, high_seq);
13749 		} else {
13750 			/* Case A */
13751 			if (SEQ_GT(ae->ack, tp->snd_max)) {
13752 				/*
13753 				 * We just send an ack since the incoming
13754 				 * ack is beyond the largest seq we sent.
13755 				 */
13756 				if ((tp->t_flags & TF_ACKNOW) == 0) {
13757 					ctf_ack_war_checks(tp, &rack->r_ctl.challenge_ack_ts, &rack->r_ctl.challenge_ack_cnt);
13758 					if (tp->t_flags && TF_ACKNOW)
13759 						rack->r_wanted_output = 1;
13760 				}
13761 			} else {
13762 				nsegs++;
13763 				/* If the window changed setup to update */
13764 				if (tiwin != tp->snd_wnd) {
13765 					win_upd_ack = ae->ack;
13766 					win_seq = ae->seq;
13767 					the_win = tiwin;
13768 					rack_do_win_updates(tp, rack, the_win, win_seq, win_upd_ack, cts, high_seq);
13769 				}
13770 #ifdef TCP_ACCOUNTING
13771 				/* Account for the acks */
13772 				if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13773 					tp->tcp_cnt_counters[CNT_OF_ACKS_IN] += (((ae->ack - high_seq) + segsiz - 1) / segsiz);
13774 				}
13775 				counter_u64_add(tcp_cnt_counters[CNT_OF_ACKS_IN],
13776 						(((ae->ack - high_seq) + segsiz - 1) / segsiz));
13777 #endif
13778 				high_seq = ae->ack;
13779 				if (SEQ_GEQ(high_seq, rack->r_ctl.roundends)) {
13780 					rack->r_ctl.current_round++;
13781 					rack->r_ctl.roundends = tp->snd_max;
13782 					if (CC_ALGO(tp)->newround != NULL) {
13783 						CC_ALGO(tp)->newround(tp->ccv, rack->r_ctl.current_round);
13784 					}
13785 				}
13786 				/* Setup our act_rcv_time */
13787 				if ((ae->flags & TSTMP_LRO) || (ae->flags & TSTMP_HDWR)) {
13788 					ts.tv_sec = ae->timestamp / 1000000000;
13789 					ts.tv_nsec = ae->timestamp % 1000000000;
13790 					rack->r_ctl.act_rcv_time.tv_sec = ts.tv_sec;
13791 					rack->r_ctl.act_rcv_time.tv_usec = ts.tv_nsec/1000;
13792 				} else {
13793 					rack->r_ctl.act_rcv_time = *tv;
13794 				}
13795 				rack_process_to_cumack(tp, rack, ae->ack, cts, to);
13796 				if (rack->rc_dsack_round_seen) {
13797 					/* Is the dsack round over? */
13798 					if (SEQ_GEQ(ae->ack, rack->r_ctl.dsack_round_end)) {
13799 						/* Yes it is */
13800 						rack->rc_dsack_round_seen = 0;
13801 						rack_log_dsack_event(rack, 3, __LINE__, 0, 0);
13802 					}
13803 				}
13804 			}
13805 		}
13806 		/* And lets be sure to commit the rtt measurements for this ack */
13807 		tcp_rack_xmit_timer_commit(rack, tp);
13808 #ifdef TCP_ACCOUNTING
13809 		rdstc = get_cyclecount();
13810 		if (rdstc > ts_val) {
13811 			counter_u64_add(tcp_proc_time[ae->ack_val_set] , (rdstc - ts_val));
13812 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13813 				tp->tcp_proc_time[ae->ack_val_set] += (rdstc - ts_val);
13814 				if (ae->ack_val_set == ACK_CUMACK)
13815 					tp->tcp_proc_time[CYC_HANDLE_MAP] += (rdstc - ts_val);
13816 			}
13817 		}
13818 #endif
13819 	}
13820 #ifdef TCP_ACCOUNTING
13821 	ts_val = get_cyclecount();
13822 #endif
13823 	acked_amount = acked = (high_seq - tp->snd_una);
13824 	if (acked) {
13825 		/*
13826 		 * Clear the probe not answered flag
13827 		 * since cum-ack moved forward.
13828 		 */
13829 		rack->probe_not_answered = 0;
13830 		if (rack->sack_attack_disable == 0)
13831 			rack_do_decay(rack);
13832 		if (acked >= segsiz) {
13833 			/*
13834 			 * You only get credit for
13835 			 * MSS and greater (and you get extra
13836 			 * credit for larger cum-ack moves).
13837 			 */
13838 			int ac;
13839 
13840 			ac = acked / segsiz;
13841 			rack->r_ctl.ack_count += ac;
13842 			counter_u64_add(rack_ack_total, ac);
13843 		}
13844 		if (rack->r_ctl.ack_count > 0xfff00000) {
13845 			/*
13846 			 * reduce the number to keep us under
13847 			 * a uint32_t.
13848 			 */
13849 			rack->r_ctl.ack_count /= 2;
13850 			rack->r_ctl.sack_count /= 2;
13851 		}
13852 		if (tp->t_flags & TF_NEEDSYN) {
13853 			/*
13854 			 * T/TCP: Connection was half-synchronized, and our SYN has
13855 			 * been ACK'd (so connection is now fully synchronized).  Go
13856 			 * to non-starred state, increment snd_una for ACK of SYN,
13857 			 * and check if we can do window scaling.
13858 			 */
13859 			tp->t_flags &= ~TF_NEEDSYN;
13860 			tp->snd_una++;
13861 			acked_amount = acked = (high_seq - tp->snd_una);
13862 		}
13863 		if (acked > sbavail(&so->so_snd))
13864 			acked_amount = sbavail(&so->so_snd);
13865 #ifdef NETFLIX_EXP_DETECTION
13866 		/*
13867 		 * We only care on a cum-ack move if we are in a sack-disabled
13868 		 * state. We have already added in to the ack_count, and we never
13869 		 * would disable on a cum-ack move, so we only care to do the
13870 		 * detection if it may "undo" it, i.e. we were in disabled already.
13871 		 */
13872 		if (rack->sack_attack_disable)
13873 			rack_do_detection(tp, rack, acked_amount, segsiz);
13874 #endif
13875 		if (IN_FASTRECOVERY(tp->t_flags) &&
13876 		    (rack->rack_no_prr == 0))
13877 			rack_update_prr(tp, rack, acked_amount, high_seq);
13878 		if (IN_RECOVERY(tp->t_flags)) {
13879 			if (SEQ_LT(high_seq, tp->snd_recover) &&
13880 			    (SEQ_LT(high_seq, tp->snd_max))) {
13881 				tcp_rack_partialack(tp);
13882 			} else {
13883 				rack_post_recovery(tp, high_seq);
13884 				recovery = 1;
13885 			}
13886 		}
13887 		/* Handle the rack-log-ack part (sendmap) */
13888 		if ((sbused(&so->so_snd) == 0) &&
13889 		    (acked > acked_amount) &&
13890 		    (tp->t_state >= TCPS_FIN_WAIT_1) &&
13891 		    (tp->t_flags & TF_SENTFIN)) {
13892 			/*
13893 			 * We must be sure our fin
13894 			 * was sent and acked (we can be
13895 			 * in FIN_WAIT_1 without having
13896 			 * sent the fin).
13897 			 */
13898 			ourfinisacked = 1;
13899 			/*
13900 			 * Lets make sure snd_una is updated
13901 			 * since most likely acked_amount = 0 (it
13902 			 * should be).
13903 			 */
13904 			tp->snd_una = high_seq;
13905 		}
13906 		/* Did we make a RTO error? */
13907 		if ((tp->t_flags & TF_PREVVALID) &&
13908 		    ((tp->t_flags & TF_RCVD_TSTMP) == 0)) {
13909 			tp->t_flags &= ~TF_PREVVALID;
13910 			if (tp->t_rxtshift == 1 &&
13911 			    (int)(ticks - tp->t_badrxtwin) < 0)
13912 				rack_cong_signal(tp, CC_RTO_ERR, high_seq);
13913 		}
13914 		/* Handle the data in the socket buffer */
13915 		KMOD_TCPSTAT_ADD(tcps_rcvackpack, 1);
13916 		KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
13917 		if (acked_amount > 0) {
13918 			struct mbuf *mfree;
13919 
13920 			rack_ack_received(tp, rack, high_seq, nsegs, CC_ACK, recovery);
13921 			SOCKBUF_LOCK(&so->so_snd);
13922 			mfree = sbcut_locked(&so->so_snd, acked_amount);
13923 			tp->snd_una = high_seq;
13924 			/* Note we want to hold the sb lock through the sendmap adjust */
13925 			rack_adjust_sendmap(rack, &so->so_snd, tp->snd_una);
13926 			/* Wake up the socket if we have room to write more */
13927 			rack_log_wakeup(tp,rack, &so->so_snd, acked, 2);
13928 			sowwakeup_locked(so);
13929 			m_freem(mfree);
13930 		}
13931 		/* update progress */
13932 		tp->t_acktime = ticks;
13933 		rack_log_progress_event(rack, tp, tp->t_acktime,
13934 					PROGRESS_UPDATE, __LINE__);
13935 		/* Clear out shifts and such */
13936 		tp->t_rxtshift = 0;
13937 		RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
13938 				   rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
13939 		rack->rc_tlp_in_progress = 0;
13940 		rack->r_ctl.rc_tlp_cnt_out = 0;
13941 		/* Send recover and snd_nxt must be dragged along */
13942 		if (SEQ_GT(tp->snd_una, tp->snd_recover))
13943 			tp->snd_recover = tp->snd_una;
13944 		if (SEQ_LT(tp->snd_nxt, tp->snd_una))
13945 			tp->snd_nxt = tp->snd_una;
13946 		/*
13947 		 * If the RXT timer is running we want to
13948 		 * stop it, so we can restart a TLP (or new RXT).
13949 		 */
13950 		if (rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT)
13951 			rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
13952 #ifdef NETFLIX_HTTP_LOGGING
13953 		tcp_http_check_for_comp(rack->rc_tp, high_seq);
13954 #endif
13955 		tp->snd_wl2 = high_seq;
13956 		tp->t_dupacks = 0;
13957 		if (under_pacing &&
13958 		    (rack->use_fixed_rate == 0) &&
13959 		    (rack->in_probe_rtt == 0) &&
13960 		    rack->rc_gp_dyn_mul &&
13961 		    rack->rc_always_pace) {
13962 			/* Check if we are dragging bottom */
13963 			rack_check_bottom_drag(tp, rack, so, acked);
13964 		}
13965 		if (tp->snd_una == tp->snd_max) {
13966 			tp->t_flags &= ~TF_PREVVALID;
13967 			rack->r_ctl.retran_during_recovery = 0;
13968 			rack->r_ctl.dsack_byte_cnt = 0;
13969 			rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
13970 			if (rack->r_ctl.rc_went_idle_time == 0)
13971 				rack->r_ctl.rc_went_idle_time = 1;
13972 			rack_log_progress_event(rack, tp, 0, PROGRESS_CLEAR, __LINE__);
13973 			if (sbavail(&tp->t_inpcb->inp_socket->so_snd) == 0)
13974 				tp->t_acktime = 0;
13975 			/* Set so we might enter persists... */
13976 			rack->r_wanted_output = 1;
13977 			rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
13978 			sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
13979 			if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
13980 			    (sbavail(&so->so_snd) == 0) &&
13981 			    (tp->t_flags2 & TF2_DROP_AF_DATA)) {
13982 				/*
13983 				 * The socket was gone and the
13984 				 * peer sent data (not now in the past), time to
13985 				 * reset him.
13986 				 */
13987 				rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
13988 				/* tcp_close will kill the inp pre-log the Reset */
13989 				tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
13990 #ifdef TCP_ACCOUNTING
13991 				rdstc = get_cyclecount();
13992 				if (rdstc > ts_val) {
13993 					counter_u64_add(tcp_proc_time[ACK_CUMACK] , (rdstc - ts_val));
13994 					if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13995 						tp->tcp_proc_time[ACK_CUMACK] += (rdstc - ts_val);
13996 						tp->tcp_proc_time[CYC_HANDLE_ACK] += (rdstc - ts_val);
13997 					}
13998 				}
13999 #endif
14000 				m_freem(m);
14001 				tp = tcp_close(tp);
14002 				if (tp == NULL) {
14003 #ifdef TCP_ACCOUNTING
14004 					sched_unpin();
14005 #endif
14006 					return (1);
14007 				}
14008 				/*
14009 				 * We would normally do drop-with-reset which would
14010 				 * send back a reset. We can't since we don't have
14011 				 * all the needed bits. Instead lets arrange for
14012 				 * a call to tcp_output(). That way since we
14013 				 * are in the closed state we will generate a reset.
14014 				 *
14015 				 * Note if tcp_accounting is on we don't unpin since
14016 				 * we do that after the goto label.
14017 				 */
14018 				goto send_out_a_rst;
14019 			}
14020 			if ((sbused(&so->so_snd) == 0) &&
14021 			    (tp->t_state >= TCPS_FIN_WAIT_1) &&
14022 			    (tp->t_flags & TF_SENTFIN)) {
14023 				/*
14024 				 * If we can't receive any more data, then closing user can
14025 				 * proceed. Starting the timer is contrary to the
14026 				 * specification, but if we don't get a FIN we'll hang
14027 				 * forever.
14028 				 *
14029 				 */
14030 				if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
14031 					soisdisconnected(so);
14032 					tcp_timer_activate(tp, TT_2MSL,
14033 							   (tcp_fast_finwait2_recycle ?
14034 							    tcp_finwait2_timeout :
14035 							    TP_MAXIDLE(tp)));
14036 				}
14037 				if (ourfinisacked == 0) {
14038 					/*
14039 					 * We don't change to fin-wait-2 if we have our fin acked
14040 					 * which means we are probably in TCPS_CLOSING.
14041 					 */
14042 					tcp_state_change(tp, TCPS_FIN_WAIT_2);
14043 				}
14044 			}
14045 		}
14046 		/* Wake up the socket if we have room to write more */
14047 		if (sbavail(&so->so_snd)) {
14048 			rack->r_wanted_output = 1;
14049 			if (ctf_progress_timeout_check(tp, true)) {
14050 				rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
14051 							tp, tick, PROGRESS_DROP, __LINE__);
14052 				tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
14053 				/*
14054 				 * We cheat here and don't send a RST, we should send one
14055 				 * when the pacer drops the connection.
14056 				 */
14057 #ifdef TCP_ACCOUNTING
14058 				rdstc = get_cyclecount();
14059 				if (rdstc > ts_val) {
14060 					counter_u64_add(tcp_proc_time[ACK_CUMACK] , (rdstc - ts_val));
14061 					if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
14062 						tp->tcp_proc_time[ACK_CUMACK] += (rdstc - ts_val);
14063 						tp->tcp_proc_time[CYC_HANDLE_ACK] += (rdstc - ts_val);
14064 					}
14065 				}
14066 				sched_unpin();
14067 #endif
14068 				INP_WUNLOCK(rack->rc_inp);
14069 				m_freem(m);
14070 				return (1);
14071 			}
14072 		}
14073 		if (ourfinisacked) {
14074 			switch(tp->t_state) {
14075 			case TCPS_CLOSING:
14076 #ifdef TCP_ACCOUNTING
14077 				rdstc = get_cyclecount();
14078 				if (rdstc > ts_val) {
14079 					counter_u64_add(tcp_proc_time[ACK_CUMACK] ,
14080 							(rdstc - ts_val));
14081 					if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
14082 						tp->tcp_proc_time[ACK_CUMACK] += (rdstc - ts_val);
14083 						tp->tcp_proc_time[CYC_HANDLE_ACK] += (rdstc - ts_val);
14084 					}
14085 				}
14086 				sched_unpin();
14087 #endif
14088 				tcp_twstart(tp);
14089 				m_freem(m);
14090 				return (1);
14091 				break;
14092 			case TCPS_LAST_ACK:
14093 #ifdef TCP_ACCOUNTING
14094 				rdstc = get_cyclecount();
14095 				if (rdstc > ts_val) {
14096 					counter_u64_add(tcp_proc_time[ACK_CUMACK] ,
14097 							(rdstc - ts_val));
14098 					if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
14099 						tp->tcp_proc_time[ACK_CUMACK] += (rdstc - ts_val);
14100 						tp->tcp_proc_time[CYC_HANDLE_ACK] += (rdstc - ts_val);
14101 					}
14102 				}
14103 				sched_unpin();
14104 #endif
14105 				tp = tcp_close(tp);
14106 				ctf_do_drop(m, tp);
14107 				return (1);
14108 				break;
14109 			case TCPS_FIN_WAIT_1:
14110 #ifdef TCP_ACCOUNTING
14111 				rdstc = get_cyclecount();
14112 				if (rdstc > ts_val) {
14113 					counter_u64_add(tcp_proc_time[ACK_CUMACK] ,
14114 							(rdstc - ts_val));
14115 					if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
14116 						tp->tcp_proc_time[ACK_CUMACK] += (rdstc - ts_val);
14117 						tp->tcp_proc_time[CYC_HANDLE_ACK] += (rdstc - ts_val);
14118 					}
14119 				}
14120 #endif
14121 				if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
14122 					soisdisconnected(so);
14123 					tcp_timer_activate(tp, TT_2MSL,
14124 							   (tcp_fast_finwait2_recycle ?
14125 							    tcp_finwait2_timeout :
14126 							    TP_MAXIDLE(tp)));
14127 				}
14128 				tcp_state_change(tp, TCPS_FIN_WAIT_2);
14129 				break;
14130 			default:
14131 				break;
14132 			}
14133 		}
14134 		if (rack->r_fast_output) {
14135 			/*
14136 			 * We re doing fast output.. can we expand that?
14137 			 */
14138 			rack_gain_for_fastoutput(rack, tp, so, acked_amount);
14139 		}
14140 #ifdef TCP_ACCOUNTING
14141 		rdstc = get_cyclecount();
14142 		if (rdstc > ts_val) {
14143 			counter_u64_add(tcp_proc_time[ACK_CUMACK] , (rdstc - ts_val));
14144 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
14145 				tp->tcp_proc_time[ACK_CUMACK] += (rdstc - ts_val);
14146 				tp->tcp_proc_time[CYC_HANDLE_ACK] += (rdstc - ts_val);
14147 			}
14148 		}
14149 
14150 	} else if (win_up_req) {
14151 		rdstc = get_cyclecount();
14152 		if (rdstc > ts_val) {
14153 			counter_u64_add(tcp_proc_time[ACK_RWND] , (rdstc - ts_val));
14154 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
14155 				tp->tcp_proc_time[ACK_RWND] += (rdstc - ts_val);
14156 			}
14157 		}
14158 #endif
14159 	}
14160 	/* Now is there a next packet, if so we are done */
14161 	m_freem(m);
14162 	did_out = 0;
14163 	if (nxt_pkt) {
14164 #ifdef TCP_ACCOUNTING
14165 		sched_unpin();
14166 #endif
14167 		rack_log_doseg_done(rack, cts, nxt_pkt, did_out, 5, nsegs);
14168 		return (0);
14169 	}
14170 	rack_handle_might_revert(tp, rack);
14171 	ctf_calc_rwin(so, tp);
14172 	if ((rack->r_wanted_output != 0) || (rack->r_fast_output != 0)) {
14173 	send_out_a_rst:
14174 		(void)tp->t_fb->tfb_tcp_output(tp);
14175 		did_out = 1;
14176 	}
14177 	rack_free_trim(rack);
14178 #ifdef TCP_ACCOUNTING
14179 	sched_unpin();
14180 #endif
14181 	rack_timer_audit(tp, rack, &so->so_snd);
14182 	rack_log_doseg_done(rack, cts, nxt_pkt, did_out, 6, nsegs);
14183 	return (0);
14184 }
14185 
14186 
14187 static int
14188 rack_do_segment_nounlock(struct mbuf *m, struct tcphdr *th, struct socket *so,
14189     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos,
14190     int32_t nxt_pkt, struct timeval *tv)
14191 {
14192 #ifdef TCP_ACCOUNTING
14193 	uint64_t ts_val;
14194 #endif
14195 	int32_t thflags, retval, did_out = 0;
14196 	int32_t way_out = 0;
14197 	/*
14198 	 * cts - is the current time from tv (caller gets ts) in microseconds.
14199 	 * ms_cts - is the current time from tv in milliseconds.
14200 	 * us_cts - is the time that LRO or hardware actually got the packet in microseconds.
14201 	 */
14202 	uint32_t cts, us_cts, ms_cts;
14203 	uint32_t tiwin;
14204 	struct timespec ts;
14205 	struct tcpopt to;
14206 	struct tcp_rack *rack;
14207 	struct rack_sendmap *rsm;
14208 	int32_t prev_state = 0;
14209 #ifdef TCP_ACCOUNTING
14210 	int ack_val_set = 0xf;
14211 #endif
14212 	int nsegs;
14213 	/*
14214 	 * tv passed from common code is from either M_TSTMP_LRO or
14215 	 * tcp_get_usecs() if no LRO m_pkthdr timestamp is present.
14216 	 */
14217 	rack = (struct tcp_rack *)tp->t_fb_ptr;
14218 	if (m->m_flags & M_ACKCMP) {
14219 		return (rack_do_compressed_ack_processing(tp, so, m, nxt_pkt, tv));
14220 	}
14221 	if (m->m_flags & M_ACKCMP) {
14222 		panic("Impossible reach m has ackcmp? m:%p tp:%p", m, tp);
14223 	}
14224 	cts = tcp_tv_to_usectick(tv);
14225 	ms_cts =  tcp_tv_to_mssectick(tv);
14226 	nsegs = m->m_pkthdr.lro_nsegs;
14227 	counter_u64_add(rack_proc_non_comp_ack, 1);
14228 	thflags = th->th_flags;
14229 #ifdef TCP_ACCOUNTING
14230 	sched_pin();
14231 	if (thflags & TH_ACK)
14232 		ts_val = get_cyclecount();
14233 #endif
14234 	if ((m->m_flags & M_TSTMP) ||
14235 	    (m->m_flags & M_TSTMP_LRO)) {
14236 		mbuf_tstmp2timespec(m, &ts);
14237 		rack->r_ctl.act_rcv_time.tv_sec = ts.tv_sec;
14238 		rack->r_ctl.act_rcv_time.tv_usec = ts.tv_nsec/1000;
14239 	} else
14240 		rack->r_ctl.act_rcv_time = *tv;
14241 	kern_prefetch(rack, &prev_state);
14242 	prev_state = 0;
14243 	/*
14244 	 * Unscale the window into a 32-bit value. For the SYN_SENT state
14245 	 * the scale is zero.
14246 	 */
14247 	tiwin = th->th_win << tp->snd_scale;
14248 #ifdef TCP_ACCOUNTING
14249 	if (thflags & TH_ACK) {
14250 		/*
14251 		 * We have a tradeoff here. We can either do what we are
14252 		 * doing i.e. pinning to this CPU and then doing the accounting
14253 		 * <or> we could do a critical enter, setup the rdtsc and cpu
14254 		 * as in below, and then validate we are on the same CPU on
14255 		 * exit. I have choosen to not do the critical enter since
14256 		 * that often will gain you a context switch, and instead lock
14257 		 * us (line above this if) to the same CPU with sched_pin(). This
14258 		 * means we may be context switched out for a higher priority
14259 		 * interupt but we won't be moved to another CPU.
14260 		 *
14261 		 * If this occurs (which it won't very often since we most likely
14262 		 * are running this code in interupt context and only a higher
14263 		 * priority will bump us ... clock?) we will falsely add in
14264 		 * to the time the interupt processing time plus the ack processing
14265 		 * time. This is ok since its a rare event.
14266 		 */
14267 		ack_val_set = tcp_do_ack_accounting(tp, th, &to, tiwin,
14268 						    ctf_fixed_maxseg(tp));
14269 	}
14270 #endif
14271 	/*
14272 	 * Parse options on any incoming segment.
14273 	 */
14274 	memset(&to, 0, sizeof(to));
14275 	tcp_dooptions(&to, (u_char *)(th + 1),
14276 	    (th->th_off << 2) - sizeof(struct tcphdr),
14277 	    (thflags & TH_SYN) ? TO_SYN : 0);
14278 	NET_EPOCH_ASSERT();
14279 	INP_WLOCK_ASSERT(tp->t_inpcb);
14280 	KASSERT(tp->t_state > TCPS_LISTEN, ("%s: TCPS_LISTEN",
14281 	    __func__));
14282 	KASSERT(tp->t_state != TCPS_TIME_WAIT, ("%s: TCPS_TIME_WAIT",
14283 	    __func__));
14284 	if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
14285 	    (tp->t_flags & TF_GPUTINPROG)) {
14286 		/*
14287 		 * We have a goodput in progress
14288 		 * and we have entered a late state.
14289 		 * Do we have enough data in the sb
14290 		 * to handle the GPUT request?
14291 		 */
14292 		uint32_t bytes;
14293 
14294 		bytes = tp->gput_ack - tp->gput_seq;
14295 		if (SEQ_GT(tp->gput_seq, tp->snd_una))
14296 			bytes += tp->gput_seq - tp->snd_una;
14297 		if (bytes > sbavail(&tp->t_inpcb->inp_socket->so_snd)) {
14298 			/*
14299 			 * There are not enough bytes in the socket
14300 			 * buffer that have been sent to cover this
14301 			 * measurement. Cancel it.
14302 			 */
14303 			rack_log_pacing_delay_calc(rack, (tp->gput_ack - tp->gput_seq) /*flex2*/,
14304 						   rack->r_ctl.rc_gp_srtt /*flex1*/,
14305 						   tp->gput_seq,
14306 						   0, 0, 18, __LINE__, NULL, 0);
14307 			tp->t_flags &= ~TF_GPUTINPROG;
14308 		}
14309 	}
14310 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
14311 		union tcp_log_stackspecific log;
14312 		struct timeval ltv;
14313 #ifdef NETFLIX_HTTP_LOGGING
14314 		struct http_sendfile_track *http_req;
14315 
14316 		if (SEQ_GT(th->th_ack, tp->snd_una)) {
14317 			http_req = tcp_http_find_req_for_seq(tp, (th->th_ack-1));
14318 		} else {
14319 			http_req = tcp_http_find_req_for_seq(tp, th->th_ack);
14320 		}
14321 #endif
14322 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
14323 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
14324 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
14325 		if (rack->rack_no_prr == 0)
14326 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
14327 		else
14328 			log.u_bbr.flex1 = 0;
14329 		log.u_bbr.use_lt_bw = rack->r_ent_rec_ns;
14330 		log.u_bbr.use_lt_bw <<= 1;
14331 		log.u_bbr.use_lt_bw |= rack->r_might_revert;
14332 		log.u_bbr.flex2 = rack->r_ctl.rc_num_maps_alloced;
14333 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
14334 		log.u_bbr.pkts_out = rack->rc_tp->t_maxseg;
14335 		log.u_bbr.flex3 = m->m_flags;
14336 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
14337 		log.u_bbr.lost = thflags;
14338 		log.u_bbr.pacing_gain = 0x1;
14339 #ifdef TCP_ACCOUNTING
14340 		log.u_bbr.cwnd_gain = ack_val_set;
14341 #endif
14342 		log.u_bbr.flex7 = 2;
14343 		if (m->m_flags & M_TSTMP) {
14344 			/* Record the hardware timestamp if present */
14345 			mbuf_tstmp2timespec(m, &ts);
14346 			ltv.tv_sec = ts.tv_sec;
14347 			ltv.tv_usec = ts.tv_nsec / 1000;
14348 			log.u_bbr.lt_epoch = tcp_tv_to_usectick(&ltv);
14349 		} else if (m->m_flags & M_TSTMP_LRO) {
14350 			/* Record the LRO the arrival timestamp */
14351 			mbuf_tstmp2timespec(m, &ts);
14352 			ltv.tv_sec = ts.tv_sec;
14353 			ltv.tv_usec = ts.tv_nsec / 1000;
14354 			log.u_bbr.flex5 = tcp_tv_to_usectick(&ltv);
14355 		}
14356 		log.u_bbr.timeStamp = tcp_get_usecs(&ltv);
14357 		/* Log the rcv time */
14358 		log.u_bbr.delRate = m->m_pkthdr.rcv_tstmp;
14359 #ifdef NETFLIX_HTTP_LOGGING
14360 		log.u_bbr.applimited = tp->t_http_closed;
14361 		log.u_bbr.applimited <<= 8;
14362 		log.u_bbr.applimited |= tp->t_http_open;
14363 		log.u_bbr.applimited <<= 8;
14364 		log.u_bbr.applimited |= tp->t_http_req;
14365 		if (http_req) {
14366 			/* Copy out any client req info */
14367 			/* seconds */
14368 			log.u_bbr.pkt_epoch = (http_req->localtime / HPTS_USEC_IN_SEC);
14369 			/* useconds */
14370 			log.u_bbr.delivered = (http_req->localtime % HPTS_USEC_IN_SEC);
14371 			log.u_bbr.rttProp = http_req->timestamp;
14372 			log.u_bbr.cur_del_rate = http_req->start;
14373 			if (http_req->flags & TCP_HTTP_TRACK_FLG_OPEN) {
14374 				log.u_bbr.flex8 |= 1;
14375 			} else {
14376 				log.u_bbr.flex8 |= 2;
14377 				log.u_bbr.bw_inuse = http_req->end;
14378 			}
14379 			log.u_bbr.flex6 = http_req->start_seq;
14380 			if (http_req->flags & TCP_HTTP_TRACK_FLG_COMP) {
14381 				log.u_bbr.flex8 |= 4;
14382 				log.u_bbr.epoch = http_req->end_seq;
14383 			}
14384 		}
14385 #endif
14386 		TCP_LOG_EVENTP(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_IN, 0,
14387 		    tlen, &log, true, &ltv);
14388 	}
14389 	if ((thflags & TH_SYN) && (thflags & TH_FIN) && V_drop_synfin) {
14390 		way_out = 4;
14391 		retval = 0;
14392 		m_freem(m);
14393 		goto done_with_input;
14394 	}
14395 	/*
14396 	 * If a segment with the ACK-bit set arrives in the SYN-SENT state
14397 	 * check SEQ.ACK first as described on page 66 of RFC 793, section 3.9.
14398 	 */
14399 	if ((tp->t_state == TCPS_SYN_SENT) && (thflags & TH_ACK) &&
14400 	    (SEQ_LEQ(th->th_ack, tp->iss) || SEQ_GT(th->th_ack, tp->snd_max))) {
14401 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
14402 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
14403 #ifdef TCP_ACCOUNTING
14404 		sched_unpin();
14405 #endif
14406 		return (1);
14407 	}
14408 	/*
14409 	 * If timestamps were negotiated during SYN/ACK and a
14410 	 * segment without a timestamp is received, silently drop
14411 	 * the segment, unless it is a RST segment or missing timestamps are
14412 	 * tolerated.
14413 	 * See section 3.2 of RFC 7323.
14414 	 */
14415 	if ((tp->t_flags & TF_RCVD_TSTMP) && !(to.to_flags & TOF_TS) &&
14416 	    ((thflags & TH_RST) == 0) && (V_tcp_tolerate_missing_ts == 0)) {
14417 		way_out = 5;
14418 		retval = 0;
14419 		m_freem(m);
14420 		goto done_with_input;
14421 	}
14422 
14423 	/*
14424 	 * Segment received on connection. Reset idle time and keep-alive
14425 	 * timer. XXX: This should be done after segment validation to
14426 	 * ignore broken/spoofed segs.
14427 	 */
14428 	if  (tp->t_idle_reduce &&
14429 	     (tp->snd_max == tp->snd_una) &&
14430 	     ((ticks - tp->t_rcvtime) >= tp->t_rxtcur)) {
14431 		counter_u64_add(rack_input_idle_reduces, 1);
14432 		rack_cc_after_idle(rack, tp);
14433 	}
14434 	tp->t_rcvtime = ticks;
14435 #ifdef STATS
14436 	stats_voi_update_abs_ulong(tp->t_stats, VOI_TCP_FRWIN, tiwin);
14437 #endif
14438 	if (tiwin > rack->r_ctl.rc_high_rwnd)
14439 		rack->r_ctl.rc_high_rwnd = tiwin;
14440 	/*
14441 	 * TCP ECN processing. XXXJTL: If we ever use ECN, we need to move
14442 	 * this to occur after we've validated the segment.
14443 	 */
14444 	if (tp->t_flags2 & TF2_ECN_PERMIT) {
14445 		if (thflags & TH_CWR) {
14446 			tp->t_flags2 &= ~TF2_ECN_SND_ECE;
14447 			tp->t_flags |= TF_ACKNOW;
14448 		}
14449 		switch (iptos & IPTOS_ECN_MASK) {
14450 		case IPTOS_ECN_CE:
14451 			tp->t_flags2 |= TF2_ECN_SND_ECE;
14452 			KMOD_TCPSTAT_INC(tcps_ecn_ce);
14453 			break;
14454 		case IPTOS_ECN_ECT0:
14455 			KMOD_TCPSTAT_INC(tcps_ecn_ect0);
14456 			break;
14457 		case IPTOS_ECN_ECT1:
14458 			KMOD_TCPSTAT_INC(tcps_ecn_ect1);
14459 			break;
14460 		}
14461 
14462 		/* Process a packet differently from RFC3168. */
14463 		cc_ecnpkt_handler(tp, th, iptos);
14464 
14465 		/* Congestion experienced. */
14466 		if (thflags & TH_ECE) {
14467 			rack_cong_signal(tp, CC_ECN, th->th_ack);
14468 		}
14469 	}
14470 
14471 	/*
14472 	 * If echoed timestamp is later than the current time, fall back to
14473 	 * non RFC1323 RTT calculation.  Normalize timestamp if syncookies
14474 	 * were used when this connection was established.
14475 	 */
14476 	if ((to.to_flags & TOF_TS) && (to.to_tsecr != 0)) {
14477 		to.to_tsecr -= tp->ts_offset;
14478 		if (TSTMP_GT(to.to_tsecr, ms_cts))
14479 			to.to_tsecr = 0;
14480 	}
14481 
14482 	/*
14483 	 * If its the first time in we need to take care of options and
14484 	 * verify we can do SACK for rack!
14485 	 */
14486 	if (rack->r_state == 0) {
14487 		/* Should be init'd by rack_init() */
14488 		KASSERT(rack->rc_inp != NULL,
14489 		    ("%s: rack->rc_inp unexpectedly NULL", __func__));
14490 		if (rack->rc_inp == NULL) {
14491 			rack->rc_inp = tp->t_inpcb;
14492 		}
14493 
14494 		/*
14495 		 * Process options only when we get SYN/ACK back. The SYN
14496 		 * case for incoming connections is handled in tcp_syncache.
14497 		 * According to RFC1323 the window field in a SYN (i.e., a
14498 		 * <SYN> or <SYN,ACK>) segment itself is never scaled. XXX
14499 		 * this is traditional behavior, may need to be cleaned up.
14500 		 */
14501 		if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) {
14502 			/* Handle parallel SYN for ECN */
14503 			if (!(thflags & TH_ACK) &&
14504 			    ((thflags & (TH_CWR | TH_ECE)) == (TH_CWR | TH_ECE)) &&
14505 			    ((V_tcp_do_ecn == 1) || (V_tcp_do_ecn == 2))) {
14506 				tp->t_flags2 |= TF2_ECN_PERMIT;
14507 				tp->t_flags2 |= TF2_ECN_SND_ECE;
14508 				TCPSTAT_INC(tcps_ecn_shs);
14509 			}
14510 			if ((to.to_flags & TOF_SCALE) &&
14511 			    (tp->t_flags & TF_REQ_SCALE)) {
14512 				tp->t_flags |= TF_RCVD_SCALE;
14513 				tp->snd_scale = to.to_wscale;
14514 			} else
14515 				tp->t_flags &= ~TF_REQ_SCALE;
14516 			/*
14517 			 * Initial send window.  It will be updated with the
14518 			 * next incoming segment to the scaled value.
14519 			 */
14520 			tp->snd_wnd = th->th_win;
14521 			rack_validate_fo_sendwin_up(tp, rack);
14522 			if ((to.to_flags & TOF_TS) &&
14523 			    (tp->t_flags & TF_REQ_TSTMP)) {
14524 				tp->t_flags |= TF_RCVD_TSTMP;
14525 				tp->ts_recent = to.to_tsval;
14526 				tp->ts_recent_age = cts;
14527 			} else
14528 				tp->t_flags &= ~TF_REQ_TSTMP;
14529 			if (to.to_flags & TOF_MSS) {
14530 				tcp_mss(tp, to.to_mss);
14531 			}
14532 			if ((tp->t_flags & TF_SACK_PERMIT) &&
14533 			    (to.to_flags & TOF_SACKPERM) == 0)
14534 				tp->t_flags &= ~TF_SACK_PERMIT;
14535 			if (IS_FASTOPEN(tp->t_flags)) {
14536 				if (to.to_flags & TOF_FASTOPEN) {
14537 					uint16_t mss;
14538 
14539 					if (to.to_flags & TOF_MSS)
14540 						mss = to.to_mss;
14541 					else
14542 						if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
14543 							mss = TCP6_MSS;
14544 						else
14545 							mss = TCP_MSS;
14546 					tcp_fastopen_update_cache(tp, mss,
14547 					    to.to_tfo_len, to.to_tfo_cookie);
14548 				} else
14549 					tcp_fastopen_disable_path(tp);
14550 			}
14551 		}
14552 		/*
14553 		 * At this point we are at the initial call. Here we decide
14554 		 * if we are doing RACK or not. We do this by seeing if
14555 		 * TF_SACK_PERMIT is set and the sack-not-required is clear.
14556 		 * The code now does do dup-ack counting so if you don't
14557 		 * switch back you won't get rack & TLP, but you will still
14558 		 * get this stack.
14559 		 */
14560 
14561 		if ((rack_sack_not_required == 0) &&
14562 		    ((tp->t_flags & TF_SACK_PERMIT) == 0)) {
14563 			tcp_switch_back_to_default(tp);
14564 			(*tp->t_fb->tfb_tcp_do_segment) (m, th, so, tp, drop_hdrlen,
14565 			    tlen, iptos);
14566 #ifdef TCP_ACCOUNTING
14567 			sched_unpin();
14568 #endif
14569 			return (1);
14570 		}
14571 		tcp_set_hpts(tp->t_inpcb);
14572 		sack_filter_clear(&rack->r_ctl.rack_sf, th->th_ack);
14573 	}
14574 	if (thflags & TH_FIN)
14575 		tcp_log_end_status(tp, TCP_EI_STATUS_CLIENT_FIN);
14576 	us_cts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
14577 	if ((rack->rc_gp_dyn_mul) &&
14578 	    (rack->use_fixed_rate == 0) &&
14579 	    (rack->rc_always_pace)) {
14580 		/* Check in on probertt */
14581 		rack_check_probe_rtt(rack, us_cts);
14582 	}
14583 	rack_clear_rate_sample(rack);
14584 	if ((rack->forced_ack) &&
14585 	    ((th->th_flags & TH_RST) == 0)) {
14586 		rack_handle_probe_response(rack, tiwin, us_cts);
14587 	}
14588 	/*
14589 	 * This is the one exception case where we set the rack state
14590 	 * always. All other times (timers etc) we must have a rack-state
14591 	 * set (so we assure we have done the checks above for SACK).
14592 	 */
14593 	rack->r_ctl.rc_rcvtime = cts;
14594 	if (rack->r_state != tp->t_state)
14595 		rack_set_state(tp, rack);
14596 	if (SEQ_GT(th->th_ack, tp->snd_una) &&
14597 	    (rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree)) != NULL)
14598 		kern_prefetch(rsm, &prev_state);
14599 	prev_state = rack->r_state;
14600 	retval = (*rack->r_substate) (m, th, so,
14601 	    tp, &to, drop_hdrlen,
14602 	    tlen, tiwin, thflags, nxt_pkt, iptos);
14603 #ifdef INVARIANTS
14604 	if ((retval == 0) &&
14605 	    (tp->t_inpcb == NULL)) {
14606 		panic("retval:%d tp:%p t_inpcb:NULL state:%d",
14607 		    retval, tp, prev_state);
14608 	}
14609 #endif
14610 	if (retval == 0) {
14611 		/*
14612 		 * If retval is 1 the tcb is unlocked and most likely the tp
14613 		 * is gone.
14614 		 */
14615 		INP_WLOCK_ASSERT(tp->t_inpcb);
14616 		if ((rack->rc_gp_dyn_mul) &&
14617 		    (rack->rc_always_pace) &&
14618 		    (rack->use_fixed_rate == 0) &&
14619 		    rack->in_probe_rtt &&
14620 		    (rack->r_ctl.rc_time_probertt_starts == 0)) {
14621 			/*
14622 			 * If we are going for target, lets recheck before
14623 			 * we output.
14624 			 */
14625 			rack_check_probe_rtt(rack, us_cts);
14626 		}
14627 		if (rack->set_pacing_done_a_iw == 0) {
14628 			/* How much has been acked? */
14629 			if ((tp->snd_una - tp->iss) > (ctf_fixed_maxseg(tp) * 10)) {
14630 				/* We have enough to set in the pacing segment size */
14631 				rack->set_pacing_done_a_iw = 1;
14632 				rack_set_pace_segments(tp, rack, __LINE__, NULL);
14633 			}
14634 		}
14635 		tcp_rack_xmit_timer_commit(rack, tp);
14636 #ifdef TCP_ACCOUNTING
14637 		/*
14638 		 * If we set the ack_val_se to what ack processing we are doing
14639 		 * we also want to track how many cycles we burned. Note
14640 		 * the bits after tcp_output we let be "free". This is because
14641 		 * we are also tracking the tcp_output times as well. Note the
14642 		 * use of 0xf here since we only have 11 counter (0 - 0xa) and
14643 		 * 0xf cannot be returned and is what we initialize it too to
14644 		 * indicate we are not doing the tabulations.
14645 		 */
14646 		if (ack_val_set != 0xf) {
14647 			uint64_t crtsc;
14648 
14649 			crtsc = get_cyclecount();
14650 			counter_u64_add(tcp_proc_time[ack_val_set] , (crtsc - ts_val));
14651 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
14652 				tp->tcp_proc_time[ack_val_set] += (crtsc - ts_val);
14653 			}
14654 		}
14655 #endif
14656 		if (nxt_pkt == 0) {
14657 			if ((rack->r_wanted_output != 0) || (rack->r_fast_output != 0)) {
14658 do_output_now:
14659 				did_out = 1;
14660 				(void)tp->t_fb->tfb_tcp_output(tp);
14661 			}
14662 			rack_start_hpts_timer(rack, tp, cts, 0, 0, 0);
14663 			rack_free_trim(rack);
14664 		}
14665 		/* Update any rounds needed */
14666 		if (SEQ_GEQ(tp->snd_una, rack->r_ctl.roundends)) {
14667 			rack->r_ctl.current_round++;
14668 			rack->r_ctl.roundends = tp->snd_max;
14669 			if (CC_ALGO(tp)->newround != NULL) {
14670 				CC_ALGO(tp)->newround(tp->ccv, rack->r_ctl.current_round);
14671 			}
14672 		}
14673 		if ((nxt_pkt == 0) &&
14674 		    ((rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) == 0) &&
14675 		    (SEQ_GT(tp->snd_max, tp->snd_una) ||
14676 		     (tp->t_flags & TF_DELACK) ||
14677 		     ((V_tcp_always_keepalive || rack->rc_inp->inp_socket->so_options & SO_KEEPALIVE) &&
14678 		      (tp->t_state <= TCPS_CLOSING)))) {
14679 			/* We could not send (probably in the hpts but stopped the timer earlier)? */
14680 			if ((tp->snd_max == tp->snd_una) &&
14681 			    ((tp->t_flags & TF_DELACK) == 0) &&
14682 			    (tcp_in_hpts(rack->rc_inp)) &&
14683 			    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
14684 				/* keep alive not needed if we are hptsi output yet */
14685 				;
14686 			} else {
14687 				int late = 0;
14688 				if (tcp_in_hpts(rack->rc_inp)) {
14689 					if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
14690 						us_cts = tcp_get_usecs(NULL);
14691 						if (TSTMP_GT(rack->r_ctl.rc_last_output_to, us_cts)) {
14692 							rack->r_early = 1;
14693 							rack->r_ctl.rc_agg_early += (rack->r_ctl.rc_last_output_to - us_cts);
14694 						} else
14695 							late = 1;
14696 						rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
14697 					}
14698 					tcp_hpts_remove(tp->t_inpcb, HPTS_REMOVE_OUTPUT);
14699 				}
14700 				if (late && (did_out == 0)) {
14701 					/*
14702 					 * We are late in the sending
14703 					 * and we did not call the output
14704 					 * (this probably should not happen).
14705 					 */
14706 					goto do_output_now;
14707 				}
14708 				rack_start_hpts_timer(rack, tp, tcp_get_usecs(NULL), 0, 0, 0);
14709 			}
14710 			way_out = 1;
14711 		} else if (nxt_pkt == 0) {
14712 			/* Do we have the correct timer running? */
14713 			rack_timer_audit(tp, rack, &so->so_snd);
14714 			way_out = 2;
14715 		}
14716 	done_with_input:
14717 		rack_log_doseg_done(rack, cts, nxt_pkt, did_out, way_out, max(1, nsegs));
14718 		if (did_out)
14719 			rack->r_wanted_output = 0;
14720 #ifdef INVARIANTS
14721 		if (tp->t_inpcb == NULL) {
14722 			panic("OP:%d retval:%d tp:%p t_inpcb:NULL state:%d",
14723 			      did_out,
14724 			      retval, tp, prev_state);
14725 		}
14726 #endif
14727 #ifdef TCP_ACCOUNTING
14728 	} else {
14729 		/*
14730 		 * Track the time (see above).
14731 		 */
14732 		if (ack_val_set != 0xf) {
14733 			uint64_t crtsc;
14734 
14735 			crtsc = get_cyclecount();
14736 			counter_u64_add(tcp_proc_time[ack_val_set] , (crtsc - ts_val));
14737 			/*
14738 			 * Note we *DO NOT* increment the per-tcb counters since
14739 			 * in the else the TP may be gone!!
14740 			 */
14741 		}
14742 #endif
14743 	}
14744 #ifdef TCP_ACCOUNTING
14745 	sched_unpin();
14746 #endif
14747 	return (retval);
14748 }
14749 
14750 void
14751 rack_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
14752     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos)
14753 {
14754 	struct timeval tv;
14755 
14756 	/* First lets see if we have old packets */
14757 	if (tp->t_in_pkt) {
14758 		if (ctf_do_queued_segments(so, tp, 1)) {
14759 			m_freem(m);
14760 			return;
14761 		}
14762 	}
14763 	if (m->m_flags & M_TSTMP_LRO) {
14764 		tv.tv_sec = m->m_pkthdr.rcv_tstmp /1000000000;
14765 		tv.tv_usec = (m->m_pkthdr.rcv_tstmp % 1000000000)/1000;
14766 	} else {
14767 		/* Should not be should we kassert instead? */
14768 		tcp_get_usecs(&tv);
14769 	}
14770 	if (rack_do_segment_nounlock(m, th, so, tp,
14771 				     drop_hdrlen, tlen, iptos, 0, &tv) == 0) {
14772 		INP_WUNLOCK(tp->t_inpcb);
14773 	}
14774 }
14775 
14776 struct rack_sendmap *
14777 tcp_rack_output(struct tcpcb *tp, struct tcp_rack *rack, uint32_t tsused)
14778 {
14779 	struct rack_sendmap *rsm = NULL;
14780 	int32_t idx;
14781 	uint32_t srtt = 0, thresh = 0, ts_low = 0;
14782 
14783 	/* Return the next guy to be re-transmitted */
14784 	if (RB_EMPTY(&rack->r_ctl.rc_mtree)) {
14785 		return (NULL);
14786 	}
14787 	if (tp->t_flags & TF_SENTFIN) {
14788 		/* retran the end FIN? */
14789 		return (NULL);
14790 	}
14791 	/* ok lets look at this one */
14792 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
14793 	if (rsm && ((rsm->r_flags & RACK_ACKED) == 0)) {
14794 		goto check_it;
14795 	}
14796 	rsm = rack_find_lowest_rsm(rack);
14797 	if (rsm == NULL) {
14798 		return (NULL);
14799 	}
14800 check_it:
14801 	if (((rack->rc_tp->t_flags & TF_SACK_PERMIT) == 0) &&
14802 	    (rsm->r_dupack >= DUP_ACK_THRESHOLD)) {
14803 		/*
14804 		 * No sack so we automatically do the 3 strikes and
14805 		 * retransmit (no rack timer would be started).
14806 		 */
14807 
14808 		return (rsm);
14809 	}
14810 	if (rsm->r_flags & RACK_ACKED) {
14811 		return (NULL);
14812 	}
14813 	if (((rsm->r_flags & RACK_SACK_PASSED) == 0) &&
14814 	    (rsm->r_dupack < DUP_ACK_THRESHOLD)) {
14815 		/* Its not yet ready */
14816 		return (NULL);
14817 	}
14818 	srtt = rack_grab_rtt(tp, rack);
14819 	idx = rsm->r_rtr_cnt - 1;
14820 	ts_low = (uint32_t)rsm->r_tim_lastsent[idx];
14821 	thresh = rack_calc_thresh_rack(rack, srtt, tsused);
14822 	if ((tsused == ts_low) ||
14823 	    (TSTMP_LT(tsused, ts_low))) {
14824 		/* No time since sending */
14825 		return (NULL);
14826 	}
14827 	if ((tsused - ts_low) < thresh) {
14828 		/* It has not been long enough yet */
14829 		return (NULL);
14830 	}
14831 	if ((rsm->r_dupack >= DUP_ACK_THRESHOLD) ||
14832 	    ((rsm->r_flags & RACK_SACK_PASSED) &&
14833 	     (rack->sack_attack_disable == 0))) {
14834 		/*
14835 		 * We have passed the dup-ack threshold <or>
14836 		 * a SACK has indicated this is missing.
14837 		 * Note that if you are a declared attacker
14838 		 * it is only the dup-ack threshold that
14839 		 * will cause retransmits.
14840 		 */
14841 		/* log retransmit reason */
14842 		rack_log_retran_reason(rack, rsm, (tsused - ts_low), thresh, 1);
14843 		rack->r_fast_output = 0;
14844 		return (rsm);
14845 	}
14846 	return (NULL);
14847 }
14848 
14849 static void
14850 rack_log_pacing_delay_calc(struct tcp_rack *rack, uint32_t len, uint32_t slot,
14851 			   uint64_t bw_est, uint64_t bw, uint64_t len_time, int method,
14852 			   int line, struct rack_sendmap *rsm, uint8_t quality)
14853 {
14854 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
14855 		union tcp_log_stackspecific log;
14856 		struct timeval tv;
14857 
14858 		memset(&log, 0, sizeof(log));
14859 		log.u_bbr.flex1 = slot;
14860 		log.u_bbr.flex2 = len;
14861 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_min_segs;
14862 		log.u_bbr.flex4 = rack->r_ctl.rc_pace_max_segs;
14863 		log.u_bbr.flex5 = rack->r_ctl.rack_per_of_gp_ss;
14864 		log.u_bbr.flex6 = rack->r_ctl.rack_per_of_gp_ca;
14865 		log.u_bbr.use_lt_bw = rack->rc_ack_can_sendout_data;
14866 		log.u_bbr.use_lt_bw <<= 1;
14867 		log.u_bbr.use_lt_bw |= rack->r_late;
14868 		log.u_bbr.use_lt_bw <<= 1;
14869 		log.u_bbr.use_lt_bw |= rack->r_early;
14870 		log.u_bbr.use_lt_bw <<= 1;
14871 		log.u_bbr.use_lt_bw |= rack->app_limited_needs_set;
14872 		log.u_bbr.use_lt_bw <<= 1;
14873 		log.u_bbr.use_lt_bw |= rack->rc_gp_filled;
14874 		log.u_bbr.use_lt_bw <<= 1;
14875 		log.u_bbr.use_lt_bw |= rack->measure_saw_probe_rtt;
14876 		log.u_bbr.use_lt_bw <<= 1;
14877 		log.u_bbr.use_lt_bw |= rack->in_probe_rtt;
14878 		log.u_bbr.use_lt_bw <<= 1;
14879 		log.u_bbr.use_lt_bw |= rack->gp_ready;
14880 		log.u_bbr.pkt_epoch = line;
14881 		log.u_bbr.epoch = rack->r_ctl.rc_agg_delayed;
14882 		log.u_bbr.lt_epoch = rack->r_ctl.rc_agg_early;
14883 		log.u_bbr.applimited = rack->r_ctl.rack_per_of_gp_rec;
14884 		log.u_bbr.bw_inuse = bw_est;
14885 		log.u_bbr.delRate = bw;
14886 		if (rack->r_ctl.gp_bw == 0)
14887 			log.u_bbr.cur_del_rate = 0;
14888 		else
14889 			log.u_bbr.cur_del_rate = rack_get_bw(rack);
14890 		log.u_bbr.rttProp = len_time;
14891 		log.u_bbr.pkts_out = rack->r_ctl.rc_rack_min_rtt;
14892 		log.u_bbr.lost = rack->r_ctl.rc_probertt_sndmax_atexit;
14893 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, rsm);
14894 		if (rack->r_ctl.cwnd_to_use < rack->rc_tp->snd_ssthresh) {
14895 			/* We are in slow start */
14896 			log.u_bbr.flex7 = 1;
14897 		} else {
14898 			/* we are on congestion avoidance */
14899 			log.u_bbr.flex7 = 0;
14900 		}
14901 		log.u_bbr.flex8 = method;
14902 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
14903 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
14904 		log.u_bbr.cwnd_gain = rack->rc_gp_saw_rec;
14905 		log.u_bbr.cwnd_gain <<= 1;
14906 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ss;
14907 		log.u_bbr.cwnd_gain <<= 1;
14908 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ca;
14909 		log.u_bbr.bbr_substate = quality;
14910 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
14911 		    &rack->rc_inp->inp_socket->so_rcv,
14912 		    &rack->rc_inp->inp_socket->so_snd,
14913 		    BBR_LOG_HPTSI_CALC, 0,
14914 		    0, &log, false, &tv);
14915 	}
14916 }
14917 
14918 static uint32_t
14919 rack_get_pacing_len(struct tcp_rack *rack, uint64_t bw, uint32_t mss)
14920 {
14921 	uint32_t new_tso, user_max;
14922 
14923 	user_max = rack->rc_user_set_max_segs * mss;
14924 	if (rack->rc_force_max_seg) {
14925 		return (user_max);
14926 	}
14927 	if (rack->use_fixed_rate &&
14928 	    ((rack->r_ctl.crte == NULL) ||
14929 	     (bw != rack->r_ctl.crte->rate))) {
14930 		/* Use the user mss since we are not exactly matched */
14931 		return (user_max);
14932 	}
14933 	new_tso = tcp_get_pacing_burst_size(rack->rc_tp, bw, mss, rack_pace_one_seg, rack->r_ctl.crte, NULL);
14934 	if (new_tso > user_max)
14935 		new_tso = user_max;
14936 	return (new_tso);
14937 }
14938 
14939 static int32_t
14940 pace_to_fill_cwnd(struct tcp_rack *rack, int32_t slot, uint32_t len, uint32_t segsiz, int *capped, uint64_t *rate_wanted, uint8_t non_paced)
14941 {
14942 	uint64_t lentim, fill_bw;
14943 
14944 	/* Lets first see if we are full, if so continue with normal rate */
14945 	rack->r_via_fill_cw = 0;
14946 	if (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) > rack->r_ctl.cwnd_to_use)
14947 		return (slot);
14948 	if ((ctf_outstanding(rack->rc_tp) + (segsiz-1)) > rack->rc_tp->snd_wnd)
14949 		return (slot);
14950 	if (rack->r_ctl.rc_last_us_rtt == 0)
14951 		return (slot);
14952 	if (rack->rc_pace_fill_if_rttin_range &&
14953 	    (rack->r_ctl.rc_last_us_rtt >=
14954 	     (get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack->rtt_limit_mul))) {
14955 		/* The rtt is huge, N * smallest, lets not fill */
14956 		return (slot);
14957 	}
14958 	/*
14959 	 * first lets calculate the b/w based on the last us-rtt
14960 	 * and the sndwnd.
14961 	 */
14962 	fill_bw = rack->r_ctl.cwnd_to_use;
14963 	/* Take the rwnd if its smaller */
14964 	if (fill_bw > rack->rc_tp->snd_wnd)
14965 		fill_bw = rack->rc_tp->snd_wnd;
14966 	if (rack->r_fill_less_agg) {
14967 		/*
14968 		 * Now take away the inflight (this will reduce our
14969 		 * aggressiveness and yeah, if we get that much out in 1RTT
14970 		 * we will have had acks come back and still be behind).
14971 		 */
14972 		fill_bw -= ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
14973 	}
14974 	/* Now lets make it into a b/w */
14975 	fill_bw *= (uint64_t)HPTS_USEC_IN_SEC;
14976 	fill_bw /= (uint64_t)rack->r_ctl.rc_last_us_rtt;
14977 	/* We are below the min b/w */
14978 	if (non_paced)
14979 		*rate_wanted = fill_bw;
14980 	if ((fill_bw < RACK_MIN_BW) || (fill_bw < *rate_wanted))
14981 		return (slot);
14982 	if (rack->r_ctl.bw_rate_cap && (fill_bw > rack->r_ctl.bw_rate_cap))
14983 		fill_bw = rack->r_ctl.bw_rate_cap;
14984 	rack->r_via_fill_cw = 1;
14985 	if (rack->r_rack_hw_rate_caps &&
14986 	    (rack->r_ctl.crte != NULL)) {
14987 		uint64_t high_rate;
14988 
14989 		high_rate = tcp_hw_highest_rate(rack->r_ctl.crte);
14990 		if (fill_bw > high_rate) {
14991 			/* We are capping bw at the highest rate table entry */
14992 			if (*rate_wanted > high_rate) {
14993 				/* The original rate was also capped */
14994 				rack->r_via_fill_cw = 0;
14995 			}
14996 			rack_log_hdwr_pacing(rack,
14997 					     fill_bw, high_rate, __LINE__,
14998 					     0, 3);
14999 			fill_bw = high_rate;
15000 			if (capped)
15001 				*capped = 1;
15002 		}
15003 	} else if ((rack->r_ctl.crte == NULL) &&
15004 		   (rack->rack_hdrw_pacing == 0) &&
15005 		   (rack->rack_hdw_pace_ena) &&
15006 		   rack->r_rack_hw_rate_caps &&
15007 		   (rack->rack_attempt_hdwr_pace == 0) &&
15008 		   (rack->rc_inp->inp_route.ro_nh != NULL) &&
15009 		   (rack->rc_inp->inp_route.ro_nh->nh_ifp != NULL)) {
15010 		/*
15011 		 * Ok we may have a first attempt that is greater than our top rate
15012 		 * lets check.
15013 		 */
15014 		uint64_t high_rate;
15015 
15016 		high_rate = tcp_hw_highest_rate_ifp(rack->rc_inp->inp_route.ro_nh->nh_ifp, rack->rc_inp);
15017 		if (high_rate) {
15018 			if (fill_bw > high_rate) {
15019 				fill_bw = high_rate;
15020 				if (capped)
15021 					*capped = 1;
15022 			}
15023 		}
15024 	}
15025 	/*
15026 	 * Ok fill_bw holds our mythical b/w to fill the cwnd
15027 	 * in a rtt, what does that time wise equate too?
15028 	 */
15029 	lentim = (uint64_t)(len) * (uint64_t)HPTS_USEC_IN_SEC;
15030 	lentim /= fill_bw;
15031 	*rate_wanted = fill_bw;
15032 	if (non_paced || (lentim < slot)) {
15033 		rack_log_pacing_delay_calc(rack, len, slot, fill_bw,
15034 					   0, lentim, 12, __LINE__, NULL, 0);
15035 		return ((int32_t)lentim);
15036 	} else
15037 		return (slot);
15038 }
15039 
15040 static int32_t
15041 rack_get_pacing_delay(struct tcp_rack *rack, struct tcpcb *tp, uint32_t len, struct rack_sendmap *rsm, uint32_t segsiz)
15042 {
15043 	uint64_t srtt;
15044 	int32_t slot = 0;
15045 	int can_start_hw_pacing = 1;
15046 	int err;
15047 
15048 	if (rack->rc_always_pace == 0) {
15049 		/*
15050 		 * We use the most optimistic possible cwnd/srtt for
15051 		 * sending calculations. This will make our
15052 		 * calculation anticipate getting more through
15053 		 * quicker then possible. But thats ok we don't want
15054 		 * the peer to have a gap in data sending.
15055 		 */
15056 		uint64_t cwnd, tr_perms = 0;
15057 		int32_t reduce = 0;
15058 
15059 	old_method:
15060 		/*
15061 		 * We keep no precise pacing with the old method
15062 		 * instead we use the pacer to mitigate bursts.
15063 		 */
15064 		if (rack->r_ctl.rc_rack_min_rtt)
15065 			srtt = rack->r_ctl.rc_rack_min_rtt;
15066 		else
15067 			srtt = max(tp->t_srtt, 1);
15068 		if (rack->r_ctl.rc_rack_largest_cwnd)
15069 			cwnd = rack->r_ctl.rc_rack_largest_cwnd;
15070 		else
15071 			cwnd = rack->r_ctl.cwnd_to_use;
15072 		/* Inflate cwnd by 1000 so srtt of usecs is in ms */
15073 		tr_perms = (cwnd * 1000) / srtt;
15074 		if (tr_perms == 0) {
15075 			tr_perms = ctf_fixed_maxseg(tp);
15076 		}
15077 		/*
15078 		 * Calculate how long this will take to drain, if
15079 		 * the calculation comes out to zero, thats ok we
15080 		 * will use send_a_lot to possibly spin around for
15081 		 * more increasing tot_len_this_send to the point
15082 		 * that its going to require a pace, or we hit the
15083 		 * cwnd. Which in that case we are just waiting for
15084 		 * a ACK.
15085 		 */
15086 		slot = len / tr_perms;
15087 		/* Now do we reduce the time so we don't run dry? */
15088 		if (slot && rack_slot_reduction) {
15089 			reduce = (slot / rack_slot_reduction);
15090 			if (reduce < slot) {
15091 				slot -= reduce;
15092 			} else
15093 				slot = 0;
15094 		}
15095 		slot *= HPTS_USEC_IN_MSEC;
15096 		if (rack->rc_pace_to_cwnd) {
15097 			uint64_t rate_wanted = 0;
15098 
15099 			slot = pace_to_fill_cwnd(rack, slot, len, segsiz, NULL, &rate_wanted, 1);
15100 			rack->rc_ack_can_sendout_data = 1;
15101 			rack_log_pacing_delay_calc(rack, len, slot, rate_wanted, 0, 0, 14, __LINE__, NULL, 0);
15102 		} else
15103 			rack_log_pacing_delay_calc(rack, len, slot, tr_perms, reduce, 0, 7, __LINE__, NULL, 0);
15104 	} else {
15105 		uint64_t bw_est, res, lentim, rate_wanted;
15106 		uint32_t orig_val, segs, oh;
15107 		int capped = 0;
15108 		int prev_fill;
15109 
15110 		if ((rack->r_rr_config == 1) && rsm) {
15111 			return (rack->r_ctl.rc_min_to);
15112 		}
15113 		if (rack->use_fixed_rate) {
15114 			rate_wanted = bw_est = rack_get_fixed_pacing_bw(rack);
15115 		} else if ((rack->r_ctl.init_rate == 0) &&
15116 #ifdef NETFLIX_PEAKRATE
15117 			   (rack->rc_tp->t_maxpeakrate == 0) &&
15118 #endif
15119 			   (rack->r_ctl.gp_bw == 0)) {
15120 			/* no way to yet do an estimate */
15121 			bw_est = rate_wanted = 0;
15122 		} else {
15123 			bw_est = rack_get_bw(rack);
15124 			rate_wanted = rack_get_output_bw(rack, bw_est, rsm, &capped);
15125 		}
15126 		if ((bw_est == 0) || (rate_wanted == 0) ||
15127 		    ((rack->gp_ready == 0) && (rack->use_fixed_rate == 0))) {
15128 			/*
15129 			 * No way yet to make a b/w estimate or
15130 			 * our raise is set incorrectly.
15131 			 */
15132 			goto old_method;
15133 		}
15134 		/* We need to account for all the overheads */
15135 		segs = (len + segsiz - 1) / segsiz;
15136 		/*
15137 		 * We need the diff between 1514 bytes (e-mtu with e-hdr)
15138 		 * and how much data we put in each packet. Yes this
15139 		 * means we may be off if we are larger than 1500 bytes
15140 		 * or smaller. But this just makes us more conservative.
15141 		 */
15142 		if (rack_hw_rate_min &&
15143 		    (bw_est < rack_hw_rate_min))
15144 			can_start_hw_pacing = 0;
15145 		if (ETHERNET_SEGMENT_SIZE > segsiz)
15146 			oh = ETHERNET_SEGMENT_SIZE - segsiz;
15147 		else
15148 			oh = 0;
15149 		segs *= oh;
15150 		lentim = (uint64_t)(len + segs) * (uint64_t)HPTS_USEC_IN_SEC;
15151 		res = lentim / rate_wanted;
15152 		slot = (uint32_t)res;
15153 		orig_val = rack->r_ctl.rc_pace_max_segs;
15154 		if (rack->r_ctl.crte == NULL) {
15155 			/*
15156 			 * Only do this if we are not hardware pacing
15157 			 * since if we are doing hw-pacing below we will
15158 			 * set make a call after setting up or changing
15159 			 * the rate.
15160 			 */
15161 			rack_set_pace_segments(rack->rc_tp, rack, __LINE__, NULL);
15162 		} else if (rack->rc_inp->inp_snd_tag == NULL) {
15163 			/*
15164 			 * We lost our rate somehow, this can happen
15165 			 * if the interface changed underneath us.
15166 			 */
15167 			tcp_rel_pacing_rate(rack->r_ctl.crte, rack->rc_tp);
15168 			rack->r_ctl.crte = NULL;
15169 			/* Lets re-allow attempting to setup pacing */
15170 			rack->rack_hdrw_pacing = 0;
15171 			rack->rack_attempt_hdwr_pace = 0;
15172 			rack_log_hdwr_pacing(rack,
15173 					     rate_wanted, bw_est, __LINE__,
15174 					     0, 6);
15175 		}
15176 		/* Did we change the TSO size, if so log it */
15177 		if (rack->r_ctl.rc_pace_max_segs != orig_val)
15178 			rack_log_pacing_delay_calc(rack, len, slot, orig_val, 0, 0, 15, __LINE__, NULL, 0);
15179 		prev_fill = rack->r_via_fill_cw;
15180 		if ((rack->rc_pace_to_cwnd) &&
15181 		    (capped == 0) &&
15182 		    (rack->use_fixed_rate == 0) &&
15183 		    (rack->in_probe_rtt == 0) &&
15184 		    (IN_FASTRECOVERY(rack->rc_tp->t_flags) == 0)) {
15185 			/*
15186 			 * We want to pace at our rate *or* faster to
15187 			 * fill the cwnd to the max if its not full.
15188 			 */
15189 			slot = pace_to_fill_cwnd(rack, slot, (len+segs), segsiz, &capped, &rate_wanted, 0);
15190 		}
15191 		if ((rack->rc_inp->inp_route.ro_nh != NULL) &&
15192 		    (rack->rc_inp->inp_route.ro_nh->nh_ifp != NULL)) {
15193 			if ((rack->rack_hdw_pace_ena) &&
15194 			    (can_start_hw_pacing > 0) &&
15195 			    (rack->rack_hdrw_pacing == 0) &&
15196 			    (rack->rack_attempt_hdwr_pace == 0)) {
15197 				/*
15198 				 * Lets attempt to turn on hardware pacing
15199 				 * if we can.
15200 				 */
15201 				rack->rack_attempt_hdwr_pace = 1;
15202 				rack->r_ctl.crte = tcp_set_pacing_rate(rack->rc_tp,
15203 								       rack->rc_inp->inp_route.ro_nh->nh_ifp,
15204 								       rate_wanted,
15205 								       RS_PACING_GEQ,
15206 								       &err, &rack->r_ctl.crte_prev_rate);
15207 				if (rack->r_ctl.crte) {
15208 					rack->rack_hdrw_pacing = 1;
15209 					rack->r_ctl.rc_pace_max_segs = tcp_get_pacing_burst_size(tp, rate_wanted, segsiz,
15210 												 0, rack->r_ctl.crte,
15211 												 NULL);
15212 					rack_log_hdwr_pacing(rack,
15213 							     rate_wanted, rack->r_ctl.crte->rate, __LINE__,
15214 							     err, 0);
15215 					rack->r_ctl.last_hw_bw_req = rate_wanted;
15216 				} else {
15217 					counter_u64_add(rack_hw_pace_init_fail, 1);
15218 				}
15219 			} else if (rack->rack_hdrw_pacing &&
15220 				   (rack->r_ctl.last_hw_bw_req != rate_wanted)) {
15221 				/* Do we need to adjust our rate? */
15222 				const struct tcp_hwrate_limit_table *nrte;
15223 
15224 				if (rack->r_up_only &&
15225 				    (rate_wanted < rack->r_ctl.crte->rate)) {
15226 					/**
15227 					 * We have four possible states here
15228 					 * having to do with the previous time
15229 					 * and this time.
15230 					 *   previous  |  this-time
15231 					 * A)     0      |     0   -- fill_cw not in the picture
15232 					 * B)     1      |     0   -- we were doing a fill-cw but now are not
15233 					 * C)     1      |     1   -- all rates from fill_cw
15234 					 * D)     0      |     1   -- we were doing non-fill and now we are filling
15235 					 *
15236 					 * For case A, C and D we don't allow a drop. But for
15237 					 * case B where we now our on our steady rate we do
15238 					 * allow a drop.
15239 					 *
15240 					 */
15241 					if (!((prev_fill == 1) && (rack->r_via_fill_cw == 0)))
15242 						goto done_w_hdwr;
15243 				}
15244 				if ((rate_wanted > rack->r_ctl.crte->rate) ||
15245 				    (rate_wanted <= rack->r_ctl.crte_prev_rate)) {
15246 					if (rack_hw_rate_to_low &&
15247 					    (bw_est < rack_hw_rate_to_low)) {
15248 						/*
15249 						 * The pacing rate is too low for hardware, but
15250 						 * do allow hardware pacing to be restarted.
15251 						 */
15252 						rack_log_hdwr_pacing(rack,
15253 							     bw_est, rack->r_ctl.crte->rate, __LINE__,
15254 							     0, 5);
15255 						tcp_rel_pacing_rate(rack->r_ctl.crte, rack->rc_tp);
15256 						rack->r_ctl.crte = NULL;
15257 						rack->rack_attempt_hdwr_pace = 0;
15258 						rack->rack_hdrw_pacing = 0;
15259 						rack_set_pace_segments(rack->rc_tp, rack, __LINE__, &rate_wanted);
15260 						goto done_w_hdwr;
15261 					}
15262 					nrte = tcp_chg_pacing_rate(rack->r_ctl.crte,
15263 								   rack->rc_tp,
15264 								   rack->rc_inp->inp_route.ro_nh->nh_ifp,
15265 								   rate_wanted,
15266 								   RS_PACING_GEQ,
15267 								   &err, &rack->r_ctl.crte_prev_rate);
15268 					if (nrte == NULL) {
15269 						/* Lost the rate */
15270 						rack->rack_hdrw_pacing = 0;
15271 						rack->r_ctl.crte = NULL;
15272 						rack_log_hdwr_pacing(rack,
15273 								     rate_wanted, 0, __LINE__,
15274 								     err, 1);
15275 						rack_set_pace_segments(rack->rc_tp, rack, __LINE__, &rate_wanted);
15276 						counter_u64_add(rack_hw_pace_lost, 1);
15277 					} else if (nrte != rack->r_ctl.crte) {
15278 						rack->r_ctl.crte = nrte;
15279 						rack->r_ctl.rc_pace_max_segs = tcp_get_pacing_burst_size(tp, rate_wanted,
15280 													 segsiz, 0,
15281 													 rack->r_ctl.crte,
15282 													 NULL);
15283 						rack_log_hdwr_pacing(rack,
15284 								     rate_wanted, rack->r_ctl.crte->rate, __LINE__,
15285 								     err, 2);
15286 						rack->r_ctl.last_hw_bw_req = rate_wanted;
15287 					}
15288 				} else {
15289 					/* We just need to adjust the segment size */
15290 					rack_set_pace_segments(rack->rc_tp, rack, __LINE__, &rate_wanted);
15291 					rack_log_hdwr_pacing(rack,
15292 							     rate_wanted, rack->r_ctl.crte->rate, __LINE__,
15293 							     0, 4);
15294 					rack->r_ctl.last_hw_bw_req = rate_wanted;
15295 				}
15296 			}
15297 		}
15298 		if ((rack->r_ctl.crte != NULL) &&
15299 		    (rack->r_ctl.crte->rate == rate_wanted)) {
15300 			/*
15301 			 * We need to add a extra if the rates
15302 			 * are exactly matched. The idea is
15303 			 * we want the software to make sure the
15304 			 * queue is empty before adding more, this
15305 			 * gives us N MSS extra pace times where
15306 			 * N is our sysctl
15307 			 */
15308 			slot += (rack->r_ctl.crte->time_between * rack_hw_pace_extra_slots);
15309 		}
15310 done_w_hdwr:
15311 		if (rack_limit_time_with_srtt &&
15312 		    (rack->use_fixed_rate == 0) &&
15313 #ifdef NETFLIX_PEAKRATE
15314 		    (rack->rc_tp->t_maxpeakrate == 0) &&
15315 #endif
15316 		    (rack->rack_hdrw_pacing == 0)) {
15317 			/*
15318 			 * Sanity check, we do not allow the pacing delay
15319 			 * to be longer than the SRTT of the path. If it is
15320 			 * a slow path, then adding a packet should increase
15321 			 * the RTT and compensate for this i.e. the srtt will
15322 			 * be greater so the allowed pacing time will be greater.
15323 			 *
15324 			 * Note this restriction is not for where a peak rate
15325 			 * is set, we are doing fixed pacing or hardware pacing.
15326 			 */
15327 			if (rack->rc_tp->t_srtt)
15328 				srtt = rack->rc_tp->t_srtt;
15329 			else
15330 				srtt = RACK_INITIAL_RTO * HPTS_USEC_IN_MSEC;	/* its in ms convert */
15331 			if (srtt < (uint64_t)slot) {
15332 				rack_log_pacing_delay_calc(rack, srtt, slot, rate_wanted, bw_est, lentim, 99, __LINE__, NULL, 0);
15333 				slot = srtt;
15334 			}
15335 		}
15336 		rack_log_pacing_delay_calc(rack, len, slot, rate_wanted, bw_est, lentim, 2, __LINE__, rsm, 0);
15337 	}
15338 	if (rack->r_ctl.crte && (rack->r_ctl.crte->rs_num_enobufs > 0)) {
15339 		/*
15340 		 * If this rate is seeing enobufs when it
15341 		 * goes to send then either the nic is out
15342 		 * of gas or we are mis-estimating the time
15343 		 * somehow and not letting the queue empty
15344 		 * completely. Lets add to the pacing time.
15345 		 */
15346 		int hw_boost_delay;
15347 
15348 		hw_boost_delay = rack->r_ctl.crte->time_between * rack_enobuf_hw_boost_mult;
15349 		if (hw_boost_delay > rack_enobuf_hw_max)
15350 			hw_boost_delay = rack_enobuf_hw_max;
15351 		else if (hw_boost_delay < rack_enobuf_hw_min)
15352 			hw_boost_delay = rack_enobuf_hw_min;
15353 		slot += hw_boost_delay;
15354 	}
15355 	if (slot)
15356 		counter_u64_add(rack_calc_nonzero, 1);
15357 	else
15358 		counter_u64_add(rack_calc_zero, 1);
15359 	return (slot);
15360 }
15361 
15362 static void
15363 rack_start_gp_measurement(struct tcpcb *tp, struct tcp_rack *rack,
15364     tcp_seq startseq, uint32_t sb_offset)
15365 {
15366 	struct rack_sendmap *my_rsm = NULL;
15367 	struct rack_sendmap fe;
15368 
15369 	if (tp->t_state < TCPS_ESTABLISHED) {
15370 		/*
15371 		 * We don't start any measurements if we are
15372 		 * not at least established.
15373 		 */
15374 		return;
15375 	}
15376 	if (tp->t_state >= TCPS_FIN_WAIT_1) {
15377 		/*
15378 		 * We will get no more data into the SB
15379 		 * this means we need to have the data available
15380 		 * before we start a measurement.
15381 		 */
15382 
15383 		if (sbavail(&tp->t_inpcb->inp_socket->so_snd) <
15384 		    max(rc_init_window(rack),
15385 			(MIN_GP_WIN * ctf_fixed_maxseg(tp)))) {
15386 			/* Nope not enough data */
15387 			return;
15388 		}
15389 	}
15390 	tp->t_flags |= TF_GPUTINPROG;
15391 	rack->r_ctl.rc_gp_lowrtt = 0xffffffff;
15392 	rack->r_ctl.rc_gp_high_rwnd = rack->rc_tp->snd_wnd;
15393 	tp->gput_seq = startseq;
15394 	rack->app_limited_needs_set = 0;
15395 	if (rack->in_probe_rtt)
15396 		rack->measure_saw_probe_rtt = 1;
15397 	else if ((rack->measure_saw_probe_rtt) &&
15398 		 (SEQ_GEQ(tp->gput_seq, rack->r_ctl.rc_probertt_sndmax_atexit)))
15399 		rack->measure_saw_probe_rtt = 0;
15400 	if (rack->rc_gp_filled)
15401 		tp->gput_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
15402 	else {
15403 		/* Special case initial measurement */
15404 		struct timeval tv;
15405 
15406 		tp->gput_ts = tcp_get_usecs(&tv);
15407 		rack->r_ctl.rc_gp_output_ts = rack_to_usec_ts(&tv);
15408 	}
15409 	/*
15410 	 * We take a guess out into the future,
15411 	 * if we have no measurement and no
15412 	 * initial rate, we measure the first
15413 	 * initial-windows worth of data to
15414 	 * speed up getting some GP measurement and
15415 	 * thus start pacing.
15416 	 */
15417 	if ((rack->rc_gp_filled == 0) && (rack->r_ctl.init_rate == 0)) {
15418 		rack->app_limited_needs_set = 1;
15419 		tp->gput_ack = startseq + max(rc_init_window(rack),
15420 					      (MIN_GP_WIN * ctf_fixed_maxseg(tp)));
15421 		rack_log_pacing_delay_calc(rack,
15422 					   tp->gput_seq,
15423 					   tp->gput_ack,
15424 					   0,
15425 					   tp->gput_ts,
15426 					   rack->r_ctl.rc_app_limited_cnt,
15427 					   9,
15428 					   __LINE__, NULL, 0);
15429 		return;
15430 	}
15431 	if (sb_offset) {
15432 		/*
15433 		 * We are out somewhere in the sb
15434 		 * can we use the already outstanding data?
15435 		 */
15436 		if (rack->r_ctl.rc_app_limited_cnt == 0) {
15437 			/*
15438 			 * Yes first one is good and in this case
15439 			 * the tp->gput_ts is correctly set based on
15440 			 * the last ack that arrived (no need to
15441 			 * set things up when an ack comes in).
15442 			 */
15443 			my_rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
15444 			if ((my_rsm == NULL) ||
15445 			    (my_rsm->r_rtr_cnt != 1)) {
15446 				/* retransmission? */
15447 				goto use_latest;
15448 			}
15449 		} else {
15450 			if (rack->r_ctl.rc_first_appl == NULL) {
15451 				/*
15452 				 * If rc_first_appl is NULL
15453 				 * then the cnt should be 0.
15454 				 * This is probably an error, maybe
15455 				 * a KASSERT would be approprate.
15456 				 */
15457 				goto use_latest;
15458 			}
15459 			/*
15460 			 * If we have a marker pointer to the last one that is
15461 			 * app limited we can use that, but we need to set
15462 			 * things up so that when it gets ack'ed we record
15463 			 * the ack time (if its not already acked).
15464 			 */
15465 			rack->app_limited_needs_set = 1;
15466 			/*
15467 			 * We want to get to the rsm that is either
15468 			 * next with space i.e. over 1 MSS or the one
15469 			 * after that (after the app-limited).
15470 			 */
15471 			my_rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree,
15472 					 rack->r_ctl.rc_first_appl);
15473 			if (my_rsm) {
15474 				if ((my_rsm->r_end - my_rsm->r_start) <= ctf_fixed_maxseg(tp))
15475 					/* Have to use the next one */
15476 					my_rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree,
15477 							 my_rsm);
15478 				else {
15479 					/* Use after the first MSS of it is acked */
15480 					tp->gput_seq = my_rsm->r_start + ctf_fixed_maxseg(tp);
15481 					goto start_set;
15482 				}
15483 			}
15484 			if ((my_rsm == NULL) ||
15485 			    (my_rsm->r_rtr_cnt != 1)) {
15486 				/*
15487 				 * Either its a retransmit or
15488 				 * the last is the app-limited one.
15489 				 */
15490 				goto use_latest;
15491 			}
15492 		}
15493 		tp->gput_seq = my_rsm->r_start;
15494 start_set:
15495 		if (my_rsm->r_flags & RACK_ACKED) {
15496 			/*
15497 			 * This one has been acked use the arrival ack time
15498 			 */
15499 			tp->gput_ts = (uint32_t)my_rsm->r_ack_arrival;
15500 			rack->app_limited_needs_set = 0;
15501 		}
15502 		rack->r_ctl.rc_gp_output_ts = my_rsm->r_tim_lastsent[(my_rsm->r_rtr_cnt-1)];
15503 		tp->gput_ack = tp->gput_seq + rack_get_measure_window(tp, rack);
15504 		rack_log_pacing_delay_calc(rack,
15505 					   tp->gput_seq,
15506 					   tp->gput_ack,
15507 					   (uint64_t)my_rsm,
15508 					   tp->gput_ts,
15509 					   rack->r_ctl.rc_app_limited_cnt,
15510 					   9,
15511 					   __LINE__, NULL, 0);
15512 		return;
15513 	}
15514 
15515 use_latest:
15516 	/*
15517 	 * We don't know how long we may have been
15518 	 * idle or if this is the first-send. Lets
15519 	 * setup the flag so we will trim off
15520 	 * the first ack'd data so we get a true
15521 	 * measurement.
15522 	 */
15523 	rack->app_limited_needs_set = 1;
15524 	tp->gput_ack = startseq + rack_get_measure_window(tp, rack);
15525 	/* Find this guy so we can pull the send time */
15526 	fe.r_start = startseq;
15527 	my_rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
15528 	if (my_rsm) {
15529 		rack->r_ctl.rc_gp_output_ts = my_rsm->r_tim_lastsent[(my_rsm->r_rtr_cnt-1)];
15530 		if (my_rsm->r_flags & RACK_ACKED) {
15531 			/*
15532 			 * Unlikely since its probably what was
15533 			 * just transmitted (but I am paranoid).
15534 			 */
15535 			tp->gput_ts = (uint32_t)my_rsm->r_ack_arrival;
15536 			rack->app_limited_needs_set = 0;
15537 		}
15538 		if (SEQ_LT(my_rsm->r_start, tp->gput_seq)) {
15539 			/* This also is unlikely */
15540 			tp->gput_seq = my_rsm->r_start;
15541 		}
15542 	} else {
15543 		/*
15544 		 * TSNH unless we have some send-map limit,
15545 		 * and even at that it should not be hitting
15546 		 * that limit (we should have stopped sending).
15547 		 */
15548 		struct timeval tv;
15549 
15550 		microuptime(&tv);
15551 		rack->r_ctl.rc_gp_output_ts = rack_to_usec_ts(&tv);
15552 	}
15553 	rack_log_pacing_delay_calc(rack,
15554 				   tp->gput_seq,
15555 				   tp->gput_ack,
15556 				   (uint64_t)my_rsm,
15557 				   tp->gput_ts,
15558 				   rack->r_ctl.rc_app_limited_cnt,
15559 				   9, __LINE__, NULL, 0);
15560 }
15561 
15562 static inline uint32_t
15563 rack_what_can_we_send(struct tcpcb *tp, struct tcp_rack *rack,  uint32_t cwnd_to_use,
15564     uint32_t avail, int32_t sb_offset)
15565 {
15566 	uint32_t len;
15567 	uint32_t sendwin;
15568 
15569 	if (tp->snd_wnd > cwnd_to_use)
15570 		sendwin = cwnd_to_use;
15571 	else
15572 		sendwin = tp->snd_wnd;
15573 	if (ctf_outstanding(tp) >= tp->snd_wnd) {
15574 		/* We never want to go over our peers rcv-window */
15575 		len = 0;
15576 	} else {
15577 		uint32_t flight;
15578 
15579 		flight = ctf_flight_size(tp, rack->r_ctl.rc_sacked);
15580 		if (flight >= sendwin) {
15581 			/*
15582 			 * We have in flight what we are allowed by cwnd (if
15583 			 * it was rwnd blocking it would have hit above out
15584 			 * >= tp->snd_wnd).
15585 			 */
15586 			return (0);
15587 		}
15588 		len = sendwin - flight;
15589 		if ((len + ctf_outstanding(tp)) > tp->snd_wnd) {
15590 			/* We would send too much (beyond the rwnd) */
15591 			len = tp->snd_wnd - ctf_outstanding(tp);
15592 		}
15593 		if ((len + sb_offset) > avail) {
15594 			/*
15595 			 * We don't have that much in the SB, how much is
15596 			 * there?
15597 			 */
15598 			len = avail - sb_offset;
15599 		}
15600 	}
15601 	return (len);
15602 }
15603 
15604 static void
15605 rack_log_fsb(struct tcp_rack *rack, struct tcpcb *tp, struct socket *so, uint32_t flags,
15606 	     unsigned ipoptlen, int32_t orig_len, int32_t len, int error,
15607 	     int rsm_is_null, int optlen, int line, uint16_t mode)
15608 {
15609 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
15610 		union tcp_log_stackspecific log;
15611 		struct timeval tv;
15612 
15613 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
15614 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
15615 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
15616 		log.u_bbr.flex1 = error;
15617 		log.u_bbr.flex2 = flags;
15618 		log.u_bbr.flex3 = rsm_is_null;
15619 		log.u_bbr.flex4 = ipoptlen;
15620 		log.u_bbr.flex5 = tp->rcv_numsacks;
15621 		log.u_bbr.flex6 = rack->r_ctl.rc_agg_early;
15622 		log.u_bbr.flex7 = optlen;
15623 		log.u_bbr.flex8 = rack->r_fsb_inited;
15624 		log.u_bbr.applimited = rack->r_fast_output;
15625 		log.u_bbr.bw_inuse = rack_get_bw(rack);
15626 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, NULL);
15627 		log.u_bbr.cwnd_gain = mode;
15628 		log.u_bbr.pkts_out = orig_len;
15629 		log.u_bbr.lt_epoch = len;
15630 		log.u_bbr.delivered = line;
15631 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
15632 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
15633 		tcp_log_event_(tp, NULL, &so->so_rcv, &so->so_snd, TCP_LOG_FSB, 0,
15634 			       len, &log, false, NULL, NULL, 0, &tv);
15635 	}
15636 }
15637 
15638 
15639 static struct mbuf *
15640 rack_fo_base_copym(struct mbuf *the_m, uint32_t the_off, int32_t *plen,
15641 		   struct rack_fast_send_blk *fsb,
15642 		   int32_t seglimit, int32_t segsize, int hw_tls)
15643 {
15644 #ifdef KERN_TLS
15645 	struct ktls_session *tls, *ntls;
15646 	struct mbuf *start;
15647 #endif
15648 	struct mbuf *m, *n, **np, *smb;
15649 	struct mbuf *top;
15650 	int32_t off, soff;
15651 	int32_t len = *plen;
15652 	int32_t fragsize;
15653 	int32_t len_cp = 0;
15654 	uint32_t mlen, frags;
15655 
15656 	soff = off = the_off;
15657 	smb = m = the_m;
15658 	np = &top;
15659 	top = NULL;
15660 #ifdef KERN_TLS
15661 	if (hw_tls && (m->m_flags & M_EXTPG))
15662 		tls = m->m_epg_tls;
15663 	else
15664 		tls = NULL;
15665 	start = m;
15666 #endif
15667 	while (len > 0) {
15668 		if (m == NULL) {
15669 			*plen = len_cp;
15670 			break;
15671 		}
15672 #ifdef KERN_TLS
15673 		if (hw_tls) {
15674 			if (m->m_flags & M_EXTPG)
15675 				ntls = m->m_epg_tls;
15676 			else
15677 				ntls = NULL;
15678 
15679 			/*
15680 			 * Avoid mixing TLS records with handshake
15681 			 * data or TLS records from different
15682 			 * sessions.
15683 			 */
15684 			if (tls != ntls) {
15685 				MPASS(m != start);
15686 				*plen = len_cp;
15687 				break;
15688 			}
15689 		}
15690 #endif
15691 		mlen = min(len, m->m_len - off);
15692 		if (seglimit) {
15693 			/*
15694 			 * For M_EXTPG mbufs, add 3 segments
15695 			 * + 1 in case we are crossing page boundaries
15696 			 * + 2 in case the TLS hdr/trailer are used
15697 			 * It is cheaper to just add the segments
15698 			 * than it is to take the cache miss to look
15699 			 * at the mbuf ext_pgs state in detail.
15700 			 */
15701 			if (m->m_flags & M_EXTPG) {
15702 				fragsize = min(segsize, PAGE_SIZE);
15703 				frags = 3;
15704 			} else {
15705 				fragsize = segsize;
15706 				frags = 0;
15707 			}
15708 
15709 			/* Break if we really can't fit anymore. */
15710 			if ((frags + 1) >= seglimit) {
15711 				*plen =	len_cp;
15712 				break;
15713 			}
15714 
15715 			/*
15716 			 * Reduce size if you can't copy the whole
15717 			 * mbuf. If we can't copy the whole mbuf, also
15718 			 * adjust len so the loop will end after this
15719 			 * mbuf.
15720 			 */
15721 			if ((frags + howmany(mlen, fragsize)) >= seglimit) {
15722 				mlen = (seglimit - frags - 1) * fragsize;
15723 				len = mlen;
15724 				*plen = len_cp + len;
15725 			}
15726 			frags += howmany(mlen, fragsize);
15727 			if (frags == 0)
15728 				frags++;
15729 			seglimit -= frags;
15730 			KASSERT(seglimit > 0,
15731 			    ("%s: seglimit went too low", __func__));
15732 		}
15733 		n = m_get(M_NOWAIT, m->m_type);
15734 		*np = n;
15735 		if (n == NULL)
15736 			goto nospace;
15737 		n->m_len = mlen;
15738 		soff += mlen;
15739 		len_cp += n->m_len;
15740 		if (m->m_flags & (M_EXT|M_EXTPG)) {
15741 			n->m_data = m->m_data + off;
15742 			mb_dupcl(n, m);
15743 		} else {
15744 			bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
15745 			    (u_int)n->m_len);
15746 		}
15747 		len -= n->m_len;
15748 		off = 0;
15749 		m = m->m_next;
15750 		np = &n->m_next;
15751 		if (len || (soff == smb->m_len)) {
15752 			/*
15753 			 * We have more so we move forward  or
15754 			 * we have consumed the entire mbuf and
15755 			 * len has fell to 0.
15756 			 */
15757 			soff = 0;
15758 			smb = m;
15759 		}
15760 
15761 	}
15762 	if (fsb != NULL) {
15763 		fsb->m = smb;
15764 		fsb->off = soff;
15765 		if (smb) {
15766 			/*
15767 			 * Save off the size of the mbuf. We do
15768 			 * this so that we can recognize when it
15769 			 * has been trimmed by sbcut() as acks
15770 			 * come in.
15771 			 */
15772 			fsb->o_m_len = smb->m_len;
15773 		} else {
15774 			/*
15775 			 * This is the case where the next mbuf went to NULL. This
15776 			 * means with this copy we have sent everything in the sb.
15777 			 * In theory we could clear the fast_output flag, but lets
15778 			 * not since its possible that we could get more added
15779 			 * and acks that call the extend function which would let
15780 			 * us send more.
15781 			 */
15782 			fsb->o_m_len = 0;
15783 		}
15784 	}
15785 	return (top);
15786 nospace:
15787 	if (top)
15788 		m_freem(top);
15789 	return (NULL);
15790 
15791 }
15792 
15793 /*
15794  * This is a copy of m_copym(), taking the TSO segment size/limit
15795  * constraints into account, and advancing the sndptr as it goes.
15796  */
15797 static struct mbuf *
15798 rack_fo_m_copym(struct tcp_rack *rack, int32_t *plen,
15799 		int32_t seglimit, int32_t segsize, struct mbuf **s_mb, int *s_soff)
15800 {
15801 	struct mbuf *m, *n;
15802 	int32_t soff;
15803 
15804 	soff = rack->r_ctl.fsb.off;
15805 	m = rack->r_ctl.fsb.m;
15806 	if (rack->r_ctl.fsb.o_m_len > m->m_len) {
15807 		/*
15808 		 * The mbuf had the front of it chopped off by an ack
15809 		 * we need to adjust the soff/off by that difference.
15810 		 */
15811 		uint32_t delta;
15812 
15813 		delta = rack->r_ctl.fsb.o_m_len - m->m_len;
15814 		soff -= delta;
15815 	} else if (rack->r_ctl.fsb.o_m_len < m->m_len) {
15816 		/*
15817 		 * The mbuf was expanded probably by
15818 		 * a m_compress. Just update o_m_len.
15819 		 */
15820 		rack->r_ctl.fsb.o_m_len = m->m_len;
15821 	}
15822 	KASSERT(soff >= 0, ("%s, negative off %d", __FUNCTION__, soff));
15823 	KASSERT(*plen >= 0, ("%s, negative len %d", __FUNCTION__, *plen));
15824 	KASSERT(soff < m->m_len, ("%s rack:%p len:%u m:%p m->m_len:%u < off?",
15825 				 __FUNCTION__,
15826 				 rack, *plen, m, m->m_len));
15827 	/* Save off the right location before we copy and advance */
15828 	*s_soff = soff;
15829 	*s_mb = rack->r_ctl.fsb.m;
15830 	n = rack_fo_base_copym(m, soff, plen,
15831 			       &rack->r_ctl.fsb,
15832 			       seglimit, segsize, rack->r_ctl.fsb.hw_tls);
15833 	return (n);
15834 }
15835 
15836 static int
15837 rack_fast_rsm_output(struct tcpcb *tp, struct tcp_rack *rack, struct rack_sendmap *rsm,
15838 		     uint64_t ts_val, uint32_t cts, uint32_t ms_cts, struct timeval *tv, int len, uint8_t doing_tlp)
15839 {
15840 	/*
15841 	 * Enter the fast retransmit path. We are given that a sched_pin is
15842 	 * in place (if accounting is compliled in) and the cycle count taken
15843 	 * at the entry is in the ts_val. The concept her is that the rsm
15844 	 * now holds the mbuf offsets and such so we can directly transmit
15845 	 * without a lot of overhead, the len field is already set for
15846 	 * us to prohibit us from sending too much (usually its 1MSS).
15847 	 */
15848 	struct ip *ip = NULL;
15849 	struct udphdr *udp = NULL;
15850 	struct tcphdr *th = NULL;
15851 	struct mbuf *m = NULL;
15852 	struct inpcb *inp;
15853 	uint8_t *cpto;
15854 	struct tcp_log_buffer *lgb;
15855 #ifdef TCP_ACCOUNTING
15856 	uint64_t crtsc;
15857 	int cnt_thru = 1;
15858 #endif
15859 	struct tcpopt to;
15860 	u_char opt[TCP_MAXOLEN];
15861 	uint32_t hdrlen, optlen;
15862 	int32_t slot, segsiz, max_val, tso = 0, error, flags, ulen = 0;
15863 	uint32_t us_cts;
15864 	uint32_t if_hw_tsomaxsegcount = 0, startseq;
15865 	uint32_t if_hw_tsomaxsegsize;
15866 
15867 #ifdef INET6
15868 	struct ip6_hdr *ip6 = NULL;
15869 
15870 	if (rack->r_is_v6) {
15871 		ip6 = (struct ip6_hdr *)rack->r_ctl.fsb.tcp_ip_hdr;
15872 		hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
15873 	} else
15874 #endif				/* INET6 */
15875 	{
15876 		ip = (struct ip *)rack->r_ctl.fsb.tcp_ip_hdr;
15877 		hdrlen = sizeof(struct tcpiphdr);
15878 	}
15879 	if (tp->t_port && (V_tcp_udp_tunneling_port == 0)) {
15880 		goto failed;
15881 	}
15882 	if (doing_tlp) {
15883 		/* Its a TLP add the flag, it may already be there but be sure */
15884 		rsm->r_flags |= RACK_TLP;
15885 	} else {
15886 		/* If it was a TLP it is not not on this retransmit */
15887 		rsm->r_flags &= ~RACK_TLP;
15888 	}
15889 	startseq = rsm->r_start;
15890 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
15891 	inp = rack->rc_inp;
15892 	to.to_flags = 0;
15893 	flags = tcp_outflags[tp->t_state];
15894 	if (flags & (TH_SYN|TH_RST)) {
15895 		goto failed;
15896 	}
15897 	if (rsm->r_flags & RACK_HAS_FIN) {
15898 		/* We can't send a FIN here */
15899 		goto failed;
15900 	}
15901 	if (flags & TH_FIN) {
15902 		/* We never send a FIN */
15903 		flags &= ~TH_FIN;
15904 	}
15905 	if (tp->t_flags & TF_RCVD_TSTMP) {
15906 		to.to_tsval = ms_cts + tp->ts_offset;
15907 		to.to_tsecr = tp->ts_recent;
15908 		to.to_flags = TOF_TS;
15909 	}
15910 	optlen = tcp_addoptions(&to, opt);
15911 	hdrlen += optlen;
15912 	udp = rack->r_ctl.fsb.udp;
15913 	if (udp)
15914 		hdrlen += sizeof(struct udphdr);
15915 	if (rack->r_ctl.rc_pace_max_segs)
15916 		max_val = rack->r_ctl.rc_pace_max_segs;
15917 	else if (rack->rc_user_set_max_segs)
15918 		max_val = rack->rc_user_set_max_segs * segsiz;
15919 	else
15920 		max_val = len;
15921 	if ((tp->t_flags & TF_TSO) &&
15922 	    V_tcp_do_tso &&
15923 	    (len > segsiz) &&
15924 	    (tp->t_port == 0))
15925 		tso = 1;
15926 #ifdef INET6
15927 	if (MHLEN < hdrlen + max_linkhdr)
15928 		m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
15929 	else
15930 #endif
15931 		m = m_gethdr(M_NOWAIT, MT_DATA);
15932 	if (m == NULL)
15933 		goto failed;
15934 	m->m_data += max_linkhdr;
15935 	m->m_len = hdrlen;
15936 	th = rack->r_ctl.fsb.th;
15937 	/* Establish the len to send */
15938 	if (len > max_val)
15939 		len = max_val;
15940 	if ((tso) && (len + optlen > tp->t_maxseg)) {
15941 		uint32_t if_hw_tsomax;
15942 		int32_t max_len;
15943 
15944 		/* extract TSO information */
15945 		if_hw_tsomax = tp->t_tsomax;
15946 		if_hw_tsomaxsegcount = tp->t_tsomaxsegcount;
15947 		if_hw_tsomaxsegsize = tp->t_tsomaxsegsize;
15948 		/*
15949 		 * Check if we should limit by maximum payload
15950 		 * length:
15951 		 */
15952 		if (if_hw_tsomax != 0) {
15953 			/* compute maximum TSO length */
15954 			max_len = (if_hw_tsomax - hdrlen -
15955 				   max_linkhdr);
15956 			if (max_len <= 0) {
15957 				goto failed;
15958 			} else if (len > max_len) {
15959 				len = max_len;
15960 			}
15961 		}
15962 		if (len <= segsiz) {
15963 			/*
15964 			 * In case there are too many small fragments don't
15965 			 * use TSO:
15966 			 */
15967 			tso = 0;
15968 		}
15969 	} else {
15970 		tso = 0;
15971 	}
15972 	if ((tso == 0) && (len > segsiz))
15973 		len = segsiz;
15974 	us_cts = tcp_get_usecs(tv);
15975 	if ((len == 0) ||
15976 	    (len <= MHLEN - hdrlen - max_linkhdr)) {
15977 		goto failed;
15978 	}
15979 	th->th_seq = htonl(rsm->r_start);
15980 	th->th_ack = htonl(tp->rcv_nxt);
15981 	/*
15982 	 * The PUSH bit should only be applied
15983 	 * if the full retransmission is made. If
15984 	 * we are sending less than this is the
15985 	 * left hand edge and should not have
15986 	 * the PUSH bit.
15987 	 */
15988 	if ((rsm->r_flags & RACK_HAD_PUSH) &&
15989 	    (len == (rsm->r_end - rsm->r_start)))
15990 		flags |= TH_PUSH;
15991 	th->th_flags = flags;
15992 	th->th_win = htons((u_short)(rack->r_ctl.fsb.recwin >> tp->rcv_scale));
15993 	if (th->th_win == 0) {
15994 		tp->t_sndzerowin++;
15995 		tp->t_flags |= TF_RXWIN0SENT;
15996 	} else
15997 		tp->t_flags &= ~TF_RXWIN0SENT;
15998 	if (rsm->r_flags & RACK_TLP) {
15999 		/*
16000 		 * TLP should not count in retran count, but
16001 		 * in its own bin
16002 		 */
16003 		counter_u64_add(rack_tlp_retran, 1);
16004 		counter_u64_add(rack_tlp_retran_bytes, len);
16005 	} else {
16006 		tp->t_sndrexmitpack++;
16007 		KMOD_TCPSTAT_INC(tcps_sndrexmitpack);
16008 		KMOD_TCPSTAT_ADD(tcps_sndrexmitbyte, len);
16009 	}
16010 #ifdef STATS
16011 	stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RETXPB,
16012 				 len);
16013 #endif
16014 	if (rsm->m == NULL)
16015 		goto failed;
16016 	if (rsm->orig_m_len != rsm->m->m_len) {
16017 		/* Fix up the orig_m_len and possibly the mbuf offset */
16018 		rack_adjust_orig_mlen(rsm);
16019 	}
16020 	m->m_next = rack_fo_base_copym(rsm->m, rsm->soff, &len, NULL, if_hw_tsomaxsegcount, if_hw_tsomaxsegsize, rsm->r_hw_tls);
16021 	if (len <= segsiz) {
16022 		/*
16023 		 * Must have ran out of mbufs for the copy
16024 		 * shorten it to no longer need tso. Lets
16025 		 * not put on sendalot since we are low on
16026 		 * mbufs.
16027 		 */
16028 		tso = 0;
16029 	}
16030 	if ((m->m_next == NULL) || (len <= 0)){
16031 		goto failed;
16032 	}
16033 	if (udp) {
16034 		if (rack->r_is_v6)
16035 			ulen = hdrlen + len - sizeof(struct ip6_hdr);
16036 		else
16037 			ulen = hdrlen + len - sizeof(struct ip);
16038 		udp->uh_ulen = htons(ulen);
16039 	}
16040 	m->m_pkthdr.rcvif = (struct ifnet *)0;
16041 	m->m_pkthdr.len = hdrlen + len;	/* in6_cksum() need this */
16042 #ifdef INET6
16043 	if (rack->r_is_v6) {
16044 		if (tp->t_port) {
16045 			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
16046 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
16047 			udp->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0);
16048 			th->th_sum = htons(0);
16049 			UDPSTAT_INC(udps_opackets);
16050 		} else {
16051 			m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
16052 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
16053 			th->th_sum = in6_cksum_pseudo(ip6,
16054 						      sizeof(struct tcphdr) + optlen + len, IPPROTO_TCP,
16055 						      0);
16056 		}
16057 	}
16058 #endif
16059 #if defined(INET6) && defined(INET)
16060 	else
16061 #endif
16062 #ifdef INET
16063 	{
16064 		if (tp->t_port) {
16065 			m->m_pkthdr.csum_flags = CSUM_UDP;
16066 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
16067 			udp->uh_sum = in_pseudo(ip->ip_src.s_addr,
16068 						ip->ip_dst.s_addr, htons(ulen + IPPROTO_UDP));
16069 			th->th_sum = htons(0);
16070 			UDPSTAT_INC(udps_opackets);
16071 		} else {
16072 			m->m_pkthdr.csum_flags = CSUM_TCP;
16073 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
16074 			th->th_sum = in_pseudo(ip->ip_src.s_addr,
16075 					       ip->ip_dst.s_addr, htons(sizeof(struct tcphdr) +
16076 									IPPROTO_TCP + len + optlen));
16077 		}
16078 		/* IP version must be set here for ipv4/ipv6 checking later */
16079 		KASSERT(ip->ip_v == IPVERSION,
16080 			("%s: IP version incorrect: %d", __func__, ip->ip_v));
16081 	}
16082 #endif
16083 	if (tso) {
16084 		KASSERT(len > tp->t_maxseg - optlen,
16085 			("%s: len <= tso_segsz tp:%p", __func__, tp));
16086 		m->m_pkthdr.csum_flags |= CSUM_TSO;
16087 		m->m_pkthdr.tso_segsz = tp->t_maxseg - optlen;
16088 	}
16089 #ifdef INET6
16090 	if (rack->r_is_v6) {
16091 		ip6->ip6_hlim = rack->r_ctl.fsb.hoplimit;
16092 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
16093 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss)
16094 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
16095 		else
16096 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
16097 	}
16098 #endif
16099 #if defined(INET) && defined(INET6)
16100 	else
16101 #endif
16102 #ifdef INET
16103 	{
16104 		ip->ip_len = htons(m->m_pkthdr.len);
16105 		ip->ip_ttl = rack->r_ctl.fsb.hoplimit;
16106 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) {
16107 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
16108 			if (tp->t_port == 0 || len < V_tcp_minmss) {
16109 				ip->ip_off |= htons(IP_DF);
16110 			}
16111 		} else {
16112 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
16113 		}
16114 	}
16115 #endif
16116 	/* Time to copy in our header */
16117 	cpto = mtod(m, uint8_t *);
16118 	memcpy(cpto, rack->r_ctl.fsb.tcp_ip_hdr, rack->r_ctl.fsb.tcp_ip_hdr_len);
16119 	th = (struct tcphdr *)(cpto + ((uint8_t *)rack->r_ctl.fsb.th - rack->r_ctl.fsb.tcp_ip_hdr));
16120 	if (optlen) {
16121 		bcopy(opt, th + 1, optlen);
16122 		th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
16123 	} else {
16124 		th->th_off = sizeof(struct tcphdr) >> 2;
16125 	}
16126 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
16127 		union tcp_log_stackspecific log;
16128 
16129 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
16130 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
16131 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
16132 		if (rack->rack_no_prr)
16133 			log.u_bbr.flex1 = 0;
16134 		else
16135 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
16136 		log.u_bbr.flex2 = rack->r_ctl.rc_pace_min_segs;
16137 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_max_segs;
16138 		log.u_bbr.flex4 = max_val;
16139 		log.u_bbr.flex5 = 0;
16140 		/* Save off the early/late values */
16141 		log.u_bbr.flex6 = rack->r_ctl.rc_agg_early;
16142 		log.u_bbr.applimited = rack->r_ctl.rc_agg_delayed;
16143 		log.u_bbr.bw_inuse = rack_get_bw(rack);
16144 		if (doing_tlp == 0)
16145 			log.u_bbr.flex8 = 1;
16146 		else
16147 			log.u_bbr.flex8 = 2;
16148 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, NULL);
16149 		log.u_bbr.flex7 = 55;
16150 		log.u_bbr.pkts_out = tp->t_maxseg;
16151 		log.u_bbr.timeStamp = cts;
16152 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
16153 		log.u_bbr.lt_epoch = rack->r_ctl.cwnd_to_use;
16154 		log.u_bbr.delivered = 0;
16155 		lgb = tcp_log_event_(tp, th, NULL, NULL, TCP_LOG_OUT, ERRNO_UNK,
16156 				     len, &log, false, NULL, NULL, 0, tv);
16157 	} else
16158 		lgb = NULL;
16159 #ifdef INET6
16160 	if (rack->r_is_v6) {
16161 		error = ip6_output(m, NULL,
16162 				   &inp->inp_route6,
16163 				   0, NULL, NULL, inp);
16164 	}
16165 #endif
16166 #if defined(INET) && defined(INET6)
16167 	else
16168 #endif
16169 #ifdef INET
16170 	{
16171 		error = ip_output(m, NULL,
16172 				  &inp->inp_route,
16173 				  0, 0, inp);
16174 	}
16175 #endif
16176 	m = NULL;
16177 	if (lgb) {
16178 		lgb->tlb_errno = error;
16179 		lgb = NULL;
16180 	}
16181 	if (error) {
16182 		goto failed;
16183 	}
16184 	rack_log_output(tp, &to, len, rsm->r_start, flags, error, rack_to_usec_ts(tv),
16185 			rsm, RACK_SENT_FP, rsm->m, rsm->soff, rsm->r_hw_tls);
16186 	if (doing_tlp && (rack->fast_rsm_hack == 0)) {
16187 		rack->rc_tlp_in_progress = 1;
16188 		rack->r_ctl.rc_tlp_cnt_out++;
16189 	}
16190 	if (error == 0) {
16191 		tcp_account_for_send(tp, len, 1, doing_tlp, rsm->r_hw_tls);
16192 		if (doing_tlp) {
16193 			rack->rc_last_sent_tlp_past_cumack = 0;
16194 			rack->rc_last_sent_tlp_seq_valid = 1;
16195 			rack->r_ctl.last_sent_tlp_seq = rsm->r_start;
16196 			rack->r_ctl.last_sent_tlp_len = rsm->r_end - rsm->r_start;
16197 		}
16198 	}
16199 	tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
16200 	rack->forced_ack = 0;	/* If we send something zap the FA flag */
16201 	if (IN_FASTRECOVERY(tp->t_flags) && rsm)
16202 		rack->r_ctl.retran_during_recovery += len;
16203 	{
16204 		int idx;
16205 
16206 		idx = (len / segsiz) + 3;
16207 		if (idx >= TCP_MSS_ACCT_ATIMER)
16208 			counter_u64_add(rack_out_size[(TCP_MSS_ACCT_ATIMER-1)], 1);
16209 		else
16210 			counter_u64_add(rack_out_size[idx], 1);
16211 	}
16212 	if (tp->t_rtttime == 0) {
16213 		tp->t_rtttime = ticks;
16214 		tp->t_rtseq = startseq;
16215 		KMOD_TCPSTAT_INC(tcps_segstimed);
16216 	}
16217 	counter_u64_add(rack_fto_rsm_send, 1);
16218 	if (error && (error == ENOBUFS)) {
16219 		slot = ((1 + rack->rc_enobuf) * HPTS_USEC_IN_MSEC);
16220 		if (rack->rc_enobuf < 0x7f)
16221 			rack->rc_enobuf++;
16222 		if (slot < (10 * HPTS_USEC_IN_MSEC))
16223 			slot = 10 * HPTS_USEC_IN_MSEC;
16224 	} else
16225 		slot = rack_get_pacing_delay(rack, tp, len, NULL, segsiz);
16226 	if ((slot == 0) ||
16227 	    (rack->rc_always_pace == 0) ||
16228 	    (rack->r_rr_config == 1)) {
16229 		/*
16230 		 * We have no pacing set or we
16231 		 * are using old-style rack or
16232 		 * we are overriden to use the old 1ms pacing.
16233 		 */
16234 		slot = rack->r_ctl.rc_min_to;
16235 	}
16236 	rack_start_hpts_timer(rack, tp, cts, slot, len, 0);
16237 	if (rack->r_must_retran) {
16238 		rack->r_ctl.rc_out_at_rto -= (rsm->r_end - rsm->r_start);
16239 		if ((SEQ_GEQ(rsm->r_end, rack->r_ctl.rc_snd_max_at_rto)) ||
16240 		    ((rsm->r_flags & RACK_MUST_RXT) == 0)) {
16241 			/*
16242 			 * We have retransmitted all we need. If
16243 			 * RACK_MUST_RXT is not set then we need to
16244 			 * not retransmit this guy.
16245 			 */
16246 			rack->r_must_retran = 0;
16247 			rack->r_ctl.rc_out_at_rto = 0;
16248 			if ((rsm->r_flags & RACK_MUST_RXT) == 0) {
16249 				/* Not one we should rxt */
16250 				goto failed;
16251 			} else {
16252 				/* Clear the flag */
16253 				rsm->r_flags &= ~RACK_MUST_RXT;
16254 			}
16255 		} else {
16256 			/* Remove  the flag */
16257 			rsm->r_flags &= ~RACK_MUST_RXT;
16258 		}
16259 	}
16260 #ifdef TCP_ACCOUNTING
16261 	crtsc = get_cyclecount();
16262 	if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16263 		tp->tcp_cnt_counters[SND_OUT_DATA] += cnt_thru;
16264 	}
16265 	counter_u64_add(tcp_cnt_counters[SND_OUT_DATA], cnt_thru);
16266 	if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16267 		tp->tcp_proc_time[SND_OUT_DATA] += (crtsc - ts_val);
16268 	}
16269 	counter_u64_add(tcp_proc_time[SND_OUT_DATA], (crtsc - ts_val));
16270 	if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16271 		tp->tcp_cnt_counters[CNT_OF_MSS_OUT] += ((len + segsiz - 1) / segsiz);
16272 	}
16273 	counter_u64_add(tcp_cnt_counters[CNT_OF_MSS_OUT], ((len + segsiz - 1) / segsiz));
16274 	sched_unpin();
16275 #endif
16276 	return (0);
16277 failed:
16278 	if (m)
16279 		m_free(m);
16280 	return (-1);
16281 }
16282 
16283 static void
16284 rack_sndbuf_autoscale(struct tcp_rack *rack)
16285 {
16286 	/*
16287 	 * Automatic sizing of send socket buffer.  Often the send buffer
16288 	 * size is not optimally adjusted to the actual network conditions
16289 	 * at hand (delay bandwidth product).  Setting the buffer size too
16290 	 * small limits throughput on links with high bandwidth and high
16291 	 * delay (eg. trans-continental/oceanic links).  Setting the
16292 	 * buffer size too big consumes too much real kernel memory,
16293 	 * especially with many connections on busy servers.
16294 	 *
16295 	 * The criteria to step up the send buffer one notch are:
16296 	 *  1. receive window of remote host is larger than send buffer
16297 	 *     (with a fudge factor of 5/4th);
16298 	 *  2. send buffer is filled to 7/8th with data (so we actually
16299 	 *     have data to make use of it);
16300 	 *  3. send buffer fill has not hit maximal automatic size;
16301 	 *  4. our send window (slow start and cogestion controlled) is
16302 	 *     larger than sent but unacknowledged data in send buffer.
16303 	 *
16304 	 * Note that the rack version moves things much faster since
16305 	 * we want to avoid hitting cache lines in the rack_fast_output()
16306 	 * path so this is called much less often and thus moves
16307 	 * the SB forward by a percentage.
16308 	 */
16309 	struct socket *so;
16310 	struct tcpcb *tp;
16311 	uint32_t sendwin, scaleup;
16312 
16313 	tp = rack->rc_tp;
16314 	so = rack->rc_inp->inp_socket;
16315 	sendwin = min(rack->r_ctl.cwnd_to_use, tp->snd_wnd);
16316 	if (V_tcp_do_autosndbuf && so->so_snd.sb_flags & SB_AUTOSIZE) {
16317 		if ((tp->snd_wnd / 4 * 5) >= so->so_snd.sb_hiwat &&
16318 		    sbused(&so->so_snd) >=
16319 		    (so->so_snd.sb_hiwat / 8 * 7) &&
16320 		    sbused(&so->so_snd) < V_tcp_autosndbuf_max &&
16321 		    sendwin >= (sbused(&so->so_snd) -
16322 		    (tp->snd_nxt - tp->snd_una))) {
16323 			if (rack_autosndbuf_inc)
16324 				scaleup = (rack_autosndbuf_inc * so->so_snd.sb_hiwat) / 100;
16325 			else
16326 				scaleup = V_tcp_autosndbuf_inc;
16327 			if (scaleup < V_tcp_autosndbuf_inc)
16328 				scaleup = V_tcp_autosndbuf_inc;
16329 			scaleup += so->so_snd.sb_hiwat;
16330 			if (scaleup > V_tcp_autosndbuf_max)
16331 				scaleup = V_tcp_autosndbuf_max;
16332 			if (!sbreserve_locked(&so->so_snd, scaleup, so, curthread))
16333 				so->so_snd.sb_flags &= ~SB_AUTOSIZE;
16334 		}
16335 	}
16336 }
16337 
16338 static int
16339 rack_fast_output(struct tcpcb *tp, struct tcp_rack *rack, uint64_t ts_val,
16340 		 uint32_t cts, uint32_t ms_cts, struct timeval *tv, long tot_len, int *send_err)
16341 {
16342 	/*
16343 	 * Enter to do fast output. We are given that the sched_pin is
16344 	 * in place (if accounting is compiled in) and the cycle count taken
16345 	 * at entry is in place in ts_val. The idea here is that
16346 	 * we know how many more bytes needs to be sent (presumably either
16347 	 * during pacing or to fill the cwnd and that was greater than
16348 	 * the max-burst). We have how much to send and all the info we
16349 	 * need to just send.
16350 	 */
16351 	struct ip *ip = NULL;
16352 	struct udphdr *udp = NULL;
16353 	struct tcphdr *th = NULL;
16354 	struct mbuf *m, *s_mb;
16355 	struct inpcb *inp;
16356 	uint8_t *cpto;
16357 	struct tcp_log_buffer *lgb;
16358 #ifdef TCP_ACCOUNTING
16359 	uint64_t crtsc;
16360 #endif
16361 	struct tcpopt to;
16362 	u_char opt[TCP_MAXOLEN];
16363 	uint32_t hdrlen, optlen;
16364 	int cnt_thru = 1;
16365 	int32_t slot, segsiz, len, max_val, tso = 0, sb_offset, error, flags, ulen = 0;
16366 	uint32_t us_cts, s_soff;
16367 	uint32_t if_hw_tsomaxsegcount = 0, startseq;
16368 	uint32_t if_hw_tsomaxsegsize;
16369 	uint16_t add_flag = RACK_SENT_FP;
16370 #ifdef INET6
16371 	struct ip6_hdr *ip6 = NULL;
16372 
16373 	if (rack->r_is_v6) {
16374 		ip6 = (struct ip6_hdr *)rack->r_ctl.fsb.tcp_ip_hdr;
16375 		hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
16376 	} else
16377 #endif				/* INET6 */
16378 	{
16379 		ip = (struct ip *)rack->r_ctl.fsb.tcp_ip_hdr;
16380 		hdrlen = sizeof(struct tcpiphdr);
16381 	}
16382 	if (tp->t_port && (V_tcp_udp_tunneling_port == 0)) {
16383 		m = NULL;
16384 		goto failed;
16385 	}
16386 	startseq = tp->snd_max;
16387 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
16388 	inp = rack->rc_inp;
16389 	len = rack->r_ctl.fsb.left_to_send;
16390 	to.to_flags = 0;
16391 	flags = rack->r_ctl.fsb.tcp_flags;
16392 	if (tp->t_flags & TF_RCVD_TSTMP) {
16393 		to.to_tsval = ms_cts + tp->ts_offset;
16394 		to.to_tsecr = tp->ts_recent;
16395 		to.to_flags = TOF_TS;
16396 	}
16397 	optlen = tcp_addoptions(&to, opt);
16398 	hdrlen += optlen;
16399 	udp = rack->r_ctl.fsb.udp;
16400 	if (udp)
16401 		hdrlen += sizeof(struct udphdr);
16402 	if (rack->r_ctl.rc_pace_max_segs)
16403 		max_val = rack->r_ctl.rc_pace_max_segs;
16404 	else if (rack->rc_user_set_max_segs)
16405 		max_val = rack->rc_user_set_max_segs * segsiz;
16406 	else
16407 		max_val = len;
16408 	if ((tp->t_flags & TF_TSO) &&
16409 	    V_tcp_do_tso &&
16410 	    (len > segsiz) &&
16411 	    (tp->t_port == 0))
16412 		tso = 1;
16413 again:
16414 #ifdef INET6
16415 	if (MHLEN < hdrlen + max_linkhdr)
16416 		m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
16417 	else
16418 #endif
16419 		m = m_gethdr(M_NOWAIT, MT_DATA);
16420 	if (m == NULL)
16421 		goto failed;
16422 	m->m_data += max_linkhdr;
16423 	m->m_len = hdrlen;
16424 	th = rack->r_ctl.fsb.th;
16425 	/* Establish the len to send */
16426 	if (len > max_val)
16427 		len = max_val;
16428 	if ((tso) && (len + optlen > tp->t_maxseg)) {
16429 		uint32_t if_hw_tsomax;
16430 		int32_t max_len;
16431 
16432 		/* extract TSO information */
16433 		if_hw_tsomax = tp->t_tsomax;
16434 		if_hw_tsomaxsegcount = tp->t_tsomaxsegcount;
16435 		if_hw_tsomaxsegsize = tp->t_tsomaxsegsize;
16436 		/*
16437 		 * Check if we should limit by maximum payload
16438 		 * length:
16439 		 */
16440 		if (if_hw_tsomax != 0) {
16441 			/* compute maximum TSO length */
16442 			max_len = (if_hw_tsomax - hdrlen -
16443 				   max_linkhdr);
16444 			if (max_len <= 0) {
16445 				goto failed;
16446 			} else if (len > max_len) {
16447 				len = max_len;
16448 			}
16449 		}
16450 		if (len <= segsiz) {
16451 			/*
16452 			 * In case there are too many small fragments don't
16453 			 * use TSO:
16454 			 */
16455 			tso = 0;
16456 		}
16457 	} else {
16458 		tso = 0;
16459 	}
16460 	if ((tso == 0) && (len > segsiz))
16461 		len = segsiz;
16462 	us_cts = tcp_get_usecs(tv);
16463 	if ((len == 0) ||
16464 	    (len <= MHLEN - hdrlen - max_linkhdr)) {
16465 		goto failed;
16466 	}
16467 	sb_offset = tp->snd_max - tp->snd_una;
16468 	th->th_seq = htonl(tp->snd_max);
16469 	th->th_ack = htonl(tp->rcv_nxt);
16470 	th->th_flags = flags;
16471 	th->th_win = htons((u_short)(rack->r_ctl.fsb.recwin >> tp->rcv_scale));
16472 	if (th->th_win == 0) {
16473 		tp->t_sndzerowin++;
16474 		tp->t_flags |= TF_RXWIN0SENT;
16475 	} else
16476 		tp->t_flags &= ~TF_RXWIN0SENT;
16477 	tp->snd_up = tp->snd_una;	/* drag it along, its deprecated */
16478 	KMOD_TCPSTAT_INC(tcps_sndpack);
16479 	KMOD_TCPSTAT_ADD(tcps_sndbyte, len);
16480 #ifdef STATS
16481 	stats_voi_update_abs_u64(tp->t_stats, VOI_TCP_TXPB,
16482 				 len);
16483 #endif
16484 	if (rack->r_ctl.fsb.m == NULL)
16485 		goto failed;
16486 
16487 	/* s_mb and s_soff are saved for rack_log_output */
16488 	m->m_next = rack_fo_m_copym(rack, &len, if_hw_tsomaxsegcount, if_hw_tsomaxsegsize,
16489 				    &s_mb, &s_soff);
16490 	if (len <= segsiz) {
16491 		/*
16492 		 * Must have ran out of mbufs for the copy
16493 		 * shorten it to no longer need tso. Lets
16494 		 * not put on sendalot since we are low on
16495 		 * mbufs.
16496 		 */
16497 		tso = 0;
16498 	}
16499 	if (rack->r_ctl.fsb.rfo_apply_push &&
16500 	    (len == rack->r_ctl.fsb.left_to_send)) {
16501 		th->th_flags |= TH_PUSH;
16502 		add_flag |= RACK_HAD_PUSH;
16503 	}
16504 	if ((m->m_next == NULL) || (len <= 0)){
16505 		goto failed;
16506 	}
16507 	if (udp) {
16508 		if (rack->r_is_v6)
16509 			ulen = hdrlen + len - sizeof(struct ip6_hdr);
16510 		else
16511 			ulen = hdrlen + len - sizeof(struct ip);
16512 		udp->uh_ulen = htons(ulen);
16513 	}
16514 	m->m_pkthdr.rcvif = (struct ifnet *)0;
16515 	if (tp->t_state == TCPS_ESTABLISHED &&
16516 	    (tp->t_flags2 & TF2_ECN_PERMIT)) {
16517 		/*
16518 		 * If the peer has ECN, mark data packets with ECN capable
16519 		 * transmission (ECT). Ignore pure ack packets,
16520 		 * retransmissions.
16521 		 */
16522 		if (len > 0 && SEQ_GEQ(tp->snd_nxt, tp->snd_max)) {
16523 #ifdef INET6
16524 			if (rack->r_is_v6)
16525 				ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20);
16526 			else
16527 #endif
16528 				ip->ip_tos |= IPTOS_ECN_ECT0;
16529 			KMOD_TCPSTAT_INC(tcps_ecn_ect0);
16530 			/*
16531 			 * Reply with proper ECN notifications.
16532 			 * Only set CWR on new data segments.
16533 			 */
16534 			if (tp->t_flags2 & TF2_ECN_SND_CWR) {
16535 				flags |= TH_CWR;
16536 				tp->t_flags2 &= ~TF2_ECN_SND_CWR;
16537 			}
16538 		}
16539 		if (tp->t_flags2 & TF2_ECN_SND_ECE)
16540 			flags |= TH_ECE;
16541 	}
16542 	m->m_pkthdr.len = hdrlen + len;	/* in6_cksum() need this */
16543 #ifdef INET6
16544 	if (rack->r_is_v6) {
16545 		if (tp->t_port) {
16546 			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
16547 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
16548 			udp->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0);
16549 			th->th_sum = htons(0);
16550 			UDPSTAT_INC(udps_opackets);
16551 		} else {
16552 			m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
16553 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
16554 			th->th_sum = in6_cksum_pseudo(ip6,
16555 						      sizeof(struct tcphdr) + optlen + len, IPPROTO_TCP,
16556 						      0);
16557 		}
16558 	}
16559 #endif
16560 #if defined(INET6) && defined(INET)
16561 	else
16562 #endif
16563 #ifdef INET
16564 	{
16565 		if (tp->t_port) {
16566 			m->m_pkthdr.csum_flags = CSUM_UDP;
16567 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
16568 			udp->uh_sum = in_pseudo(ip->ip_src.s_addr,
16569 						ip->ip_dst.s_addr, htons(ulen + IPPROTO_UDP));
16570 			th->th_sum = htons(0);
16571 			UDPSTAT_INC(udps_opackets);
16572 		} else {
16573 			m->m_pkthdr.csum_flags = CSUM_TCP;
16574 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
16575 			th->th_sum = in_pseudo(ip->ip_src.s_addr,
16576 					       ip->ip_dst.s_addr, htons(sizeof(struct tcphdr) +
16577 									IPPROTO_TCP + len + optlen));
16578 		}
16579 		/* IP version must be set here for ipv4/ipv6 checking later */
16580 		KASSERT(ip->ip_v == IPVERSION,
16581 			("%s: IP version incorrect: %d", __func__, ip->ip_v));
16582 	}
16583 #endif
16584 	if (tso) {
16585 		KASSERT(len > tp->t_maxseg - optlen,
16586 			("%s: len <= tso_segsz tp:%p", __func__, tp));
16587 		m->m_pkthdr.csum_flags |= CSUM_TSO;
16588 		m->m_pkthdr.tso_segsz = tp->t_maxseg - optlen;
16589 	}
16590 #ifdef INET6
16591 	if (rack->r_is_v6) {
16592 		ip6->ip6_hlim = rack->r_ctl.fsb.hoplimit;
16593 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
16594 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss)
16595 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
16596 		else
16597 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
16598 	}
16599 #endif
16600 #if defined(INET) && defined(INET6)
16601 	else
16602 #endif
16603 #ifdef INET
16604 	{
16605 		ip->ip_len = htons(m->m_pkthdr.len);
16606 		ip->ip_ttl = rack->r_ctl.fsb.hoplimit;
16607 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) {
16608 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
16609 			if (tp->t_port == 0 || len < V_tcp_minmss) {
16610 				ip->ip_off |= htons(IP_DF);
16611 			}
16612 		} else {
16613 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
16614 		}
16615 	}
16616 #endif
16617 	/* Time to copy in our header */
16618 	cpto = mtod(m, uint8_t *);
16619 	memcpy(cpto, rack->r_ctl.fsb.tcp_ip_hdr, rack->r_ctl.fsb.tcp_ip_hdr_len);
16620 	th = (struct tcphdr *)(cpto + ((uint8_t *)rack->r_ctl.fsb.th - rack->r_ctl.fsb.tcp_ip_hdr));
16621 	if (optlen) {
16622 		bcopy(opt, th + 1, optlen);
16623 		th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
16624 	} else {
16625 		th->th_off = sizeof(struct tcphdr) >> 2;
16626 	}
16627 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
16628 		union tcp_log_stackspecific log;
16629 
16630 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
16631 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
16632 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
16633 		if (rack->rack_no_prr)
16634 			log.u_bbr.flex1 = 0;
16635 		else
16636 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
16637 		log.u_bbr.flex2 = rack->r_ctl.rc_pace_min_segs;
16638 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_max_segs;
16639 		log.u_bbr.flex4 = max_val;
16640 		log.u_bbr.flex5 = 0;
16641 		/* Save off the early/late values */
16642 		log.u_bbr.flex6 = rack->r_ctl.rc_agg_early;
16643 		log.u_bbr.applimited = rack->r_ctl.rc_agg_delayed;
16644 		log.u_bbr.bw_inuse = rack_get_bw(rack);
16645 		log.u_bbr.flex8 = 0;
16646 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, NULL);
16647 		log.u_bbr.flex7 = 44;
16648 		log.u_bbr.pkts_out = tp->t_maxseg;
16649 		log.u_bbr.timeStamp = cts;
16650 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
16651 		log.u_bbr.lt_epoch = rack->r_ctl.cwnd_to_use;
16652 		log.u_bbr.delivered = 0;
16653 		lgb = tcp_log_event_(tp, th, NULL, NULL, TCP_LOG_OUT, ERRNO_UNK,
16654 				     len, &log, false, NULL, NULL, 0, tv);
16655 	} else
16656 		lgb = NULL;
16657 #ifdef INET6
16658 	if (rack->r_is_v6) {
16659 		error = ip6_output(m, NULL,
16660 				   &inp->inp_route6,
16661 				   0, NULL, NULL, inp);
16662 	}
16663 #endif
16664 #if defined(INET) && defined(INET6)
16665 	else
16666 #endif
16667 #ifdef INET
16668 	{
16669 		error = ip_output(m, NULL,
16670 				  &inp->inp_route,
16671 				  0, 0, inp);
16672 	}
16673 #endif
16674 	if (lgb) {
16675 		lgb->tlb_errno = error;
16676 		lgb = NULL;
16677 	}
16678 	if (error) {
16679 		*send_err = error;
16680 		m = NULL;
16681 		goto failed;
16682 	}
16683 	rack_log_output(tp, &to, len, tp->snd_max, flags, error, rack_to_usec_ts(tv),
16684 			NULL, add_flag, s_mb, s_soff, rack->r_ctl.fsb.hw_tls);
16685 	m = NULL;
16686 	if (tp->snd_una == tp->snd_max) {
16687 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
16688 		rack_log_progress_event(rack, tp, ticks, PROGRESS_START, __LINE__);
16689 		tp->t_acktime = ticks;
16690 	}
16691 	if (error == 0)
16692 		tcp_account_for_send(tp, len, 0, 0, rack->r_ctl.fsb.hw_tls);
16693 
16694 	rack->forced_ack = 0;	/* If we send something zap the FA flag */
16695 	tot_len += len;
16696 	if ((tp->t_flags & TF_GPUTINPROG) == 0)
16697 		rack_start_gp_measurement(tp, rack, tp->snd_max, sb_offset);
16698 	tp->snd_max += len;
16699 	tp->snd_nxt = tp->snd_max;
16700 	{
16701 		int idx;
16702 
16703 		idx = (len / segsiz) + 3;
16704 		if (idx >= TCP_MSS_ACCT_ATIMER)
16705 			counter_u64_add(rack_out_size[(TCP_MSS_ACCT_ATIMER-1)], 1);
16706 		else
16707 			counter_u64_add(rack_out_size[idx], 1);
16708 	}
16709 	if (len <= rack->r_ctl.fsb.left_to_send)
16710 		rack->r_ctl.fsb.left_to_send -= len;
16711 	else
16712 		rack->r_ctl.fsb.left_to_send = 0;
16713 	if (rack->r_ctl.fsb.left_to_send < segsiz) {
16714 		rack->r_fast_output = 0;
16715 		rack->r_ctl.fsb.left_to_send = 0;
16716 		/* At the end of fast_output scale up the sb */
16717 		SOCKBUF_LOCK(&rack->rc_inp->inp_socket->so_snd);
16718 		rack_sndbuf_autoscale(rack);
16719 		SOCKBUF_UNLOCK(&rack->rc_inp->inp_socket->so_snd);
16720 	}
16721 	if (tp->t_rtttime == 0) {
16722 		tp->t_rtttime = ticks;
16723 		tp->t_rtseq = startseq;
16724 		KMOD_TCPSTAT_INC(tcps_segstimed);
16725 	}
16726 	if ((rack->r_ctl.fsb.left_to_send >= segsiz) &&
16727 	    (max_val > len) &&
16728 	    (tso == 0)) {
16729 		max_val -= len;
16730 		len = segsiz;
16731 		th = rack->r_ctl.fsb.th;
16732 		cnt_thru++;
16733 		goto again;
16734 	}
16735 	tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
16736 	counter_u64_add(rack_fto_send, 1);
16737 	slot = rack_get_pacing_delay(rack, tp, tot_len, NULL, segsiz);
16738 	rack_start_hpts_timer(rack, tp, cts, slot, tot_len, 0);
16739 #ifdef TCP_ACCOUNTING
16740 	crtsc = get_cyclecount();
16741 	if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16742 		tp->tcp_cnt_counters[SND_OUT_DATA] += cnt_thru;
16743 	}
16744 	counter_u64_add(tcp_cnt_counters[SND_OUT_DATA], cnt_thru);
16745 	if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16746 		tp->tcp_proc_time[SND_OUT_DATA] += (crtsc - ts_val);
16747 	}
16748 	counter_u64_add(tcp_proc_time[SND_OUT_DATA], (crtsc - ts_val));
16749 	if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16750 		tp->tcp_cnt_counters[CNT_OF_MSS_OUT] += ((tot_len + segsiz - 1) / segsiz);
16751 	}
16752 	counter_u64_add(tcp_cnt_counters[CNT_OF_MSS_OUT], ((tot_len + segsiz - 1) / segsiz));
16753 	sched_unpin();
16754 #endif
16755 	return (0);
16756 failed:
16757 	if (m)
16758 		m_free(m);
16759 	rack->r_fast_output = 0;
16760 	return (-1);
16761 }
16762 
16763 static int
16764 rack_output(struct tcpcb *tp)
16765 {
16766 	struct socket *so;
16767 	uint32_t recwin;
16768 	uint32_t sb_offset, s_moff = 0;
16769 	int32_t len, flags, error = 0;
16770 	struct mbuf *m, *s_mb = NULL;
16771 	struct mbuf *mb;
16772 	uint32_t if_hw_tsomaxsegcount = 0;
16773 	uint32_t if_hw_tsomaxsegsize;
16774 	int32_t segsiz, minseg;
16775 	long tot_len_this_send = 0;
16776 #ifdef INET
16777 	struct ip *ip = NULL;
16778 #endif
16779 #ifdef TCPDEBUG
16780 	struct ipovly *ipov = NULL;
16781 #endif
16782 	struct udphdr *udp = NULL;
16783 	struct tcp_rack *rack;
16784 	struct tcphdr *th;
16785 	uint8_t pass = 0;
16786 	uint8_t mark = 0;
16787 	uint8_t wanted_cookie = 0;
16788 	u_char opt[TCP_MAXOLEN];
16789 	unsigned ipoptlen, optlen, hdrlen, ulen=0;
16790 	uint32_t rack_seq;
16791 
16792 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
16793 	unsigned ipsec_optlen = 0;
16794 
16795 #endif
16796 	int32_t idle, sendalot;
16797 	int32_t sub_from_prr = 0;
16798 	volatile int32_t sack_rxmit;
16799 	struct rack_sendmap *rsm = NULL;
16800 	int32_t tso, mtu;
16801 	struct tcpopt to;
16802 	int32_t slot = 0;
16803 	int32_t sup_rack = 0;
16804 	uint32_t cts, ms_cts, delayed, early;
16805 	uint16_t add_flag = RACK_SENT_SP;
16806 	/* The doing_tlp flag will be set by the actual rack_timeout_tlp() */
16807 	uint8_t hpts_calling,  doing_tlp = 0;
16808 	uint32_t cwnd_to_use, pace_max_seg;
16809 	int32_t do_a_prefetch = 0;
16810 	int32_t prefetch_rsm = 0;
16811 	int32_t orig_len = 0;
16812 	struct timeval tv;
16813 	int32_t prefetch_so_done = 0;
16814 	struct tcp_log_buffer *lgb;
16815 	struct inpcb *inp;
16816 	struct sockbuf *sb;
16817 	uint64_t ts_val = 0;
16818 #ifdef TCP_ACCOUNTING
16819 	uint64_t crtsc;
16820 #endif
16821 #ifdef INET6
16822 	struct ip6_hdr *ip6 = NULL;
16823 	int32_t isipv6;
16824 #endif
16825 	uint8_t filled_all = 0;
16826 	bool hw_tls = false;
16827 
16828 	/* setup and take the cache hits here */
16829 	rack = (struct tcp_rack *)tp->t_fb_ptr;
16830 #ifdef TCP_ACCOUNTING
16831 	sched_pin();
16832 	ts_val = get_cyclecount();
16833 #endif
16834 	hpts_calling = rack->rc_inp->inp_hpts_calls;
16835 	NET_EPOCH_ASSERT();
16836 	INP_WLOCK_ASSERT(rack->rc_inp);
16837 #ifdef TCP_OFFLOAD
16838 	if (tp->t_flags & TF_TOE) {
16839 #ifdef TCP_ACCOUNTING
16840 		sched_unpin();
16841 #endif
16842 		return (tcp_offload_output(tp));
16843 	}
16844 #endif
16845 	/*
16846 	 * For TFO connections in SYN_RECEIVED, only allow the initial
16847 	 * SYN|ACK and those sent by the retransmit timer.
16848 	 */
16849 	if (IS_FASTOPEN(tp->t_flags) &&
16850 	    (tp->t_state == TCPS_SYN_RECEIVED) &&
16851 	    SEQ_GT(tp->snd_max, tp->snd_una) &&    /* initial SYN|ACK sent */
16852 	    (rack->r_ctl.rc_resend == NULL)) {         /* not a retransmit */
16853 #ifdef TCP_ACCOUNTING
16854 		sched_unpin();
16855 #endif
16856 		return (0);
16857 	}
16858 #ifdef INET6
16859 	if (rack->r_state) {
16860 		/* Use the cache line loaded if possible */
16861 		isipv6 = rack->r_is_v6;
16862 	} else {
16863 		isipv6 = (rack->rc_inp->inp_vflag & INP_IPV6) != 0;
16864 	}
16865 #endif
16866 	early = 0;
16867 	cts = tcp_get_usecs(&tv);
16868 	ms_cts = tcp_tv_to_mssectick(&tv);
16869 	if (((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0) &&
16870 	    tcp_in_hpts(rack->rc_inp)) {
16871 		/*
16872 		 * We are on the hpts for some timer but not hptsi output.
16873 		 * Remove from the hpts unconditionally.
16874 		 */
16875 		rack_timer_cancel(tp, rack, cts, __LINE__);
16876 	}
16877 	/* Are we pacing and late? */
16878 	if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
16879 	    TSTMP_GEQ(cts, rack->r_ctl.rc_last_output_to)) {
16880 		/* We are delayed */
16881 		delayed = cts - rack->r_ctl.rc_last_output_to;
16882 	} else {
16883 		delayed = 0;
16884 	}
16885 	/* Do the timers, which may override the pacer */
16886 	if (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) {
16887 		if (rack_process_timers(tp, rack, cts, hpts_calling, &doing_tlp)) {
16888 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_ATIMER], 1);
16889 #ifdef TCP_ACCOUNTING
16890 			sched_unpin();
16891 #endif
16892 			return (0);
16893 		}
16894 	}
16895 	if (rack->rc_in_persist) {
16896 		if (tcp_in_hpts(rack->rc_inp) == 0) {
16897 			/* Timer is not running */
16898 			rack_start_hpts_timer(rack, tp, cts, 0, 0, 0);
16899 		}
16900 #ifdef TCP_ACCOUNTING
16901 		sched_unpin();
16902 #endif
16903 		return (0);
16904 	}
16905 	if ((rack->r_timer_override) ||
16906 	    (rack->rc_ack_can_sendout_data) ||
16907 	    (delayed) ||
16908 	    (tp->t_state < TCPS_ESTABLISHED)) {
16909 		rack->rc_ack_can_sendout_data = 0;
16910 		if (tcp_in_hpts(rack->rc_inp))
16911 			tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
16912 	} else if (tcp_in_hpts(rack->rc_inp)) {
16913 		/*
16914 		 * On the hpts you can't pass even if ACKNOW is on, we will
16915 		 * when the hpts fires.
16916 		 */
16917 #ifdef TCP_ACCOUNTING
16918 		crtsc = get_cyclecount();
16919 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16920 			tp->tcp_proc_time[SND_BLOCKED] += (crtsc - ts_val);
16921 		}
16922 		counter_u64_add(tcp_proc_time[SND_BLOCKED], (crtsc - ts_val));
16923 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16924 			tp->tcp_cnt_counters[SND_BLOCKED]++;
16925 		}
16926 		counter_u64_add(tcp_cnt_counters[SND_BLOCKED], 1);
16927 		sched_unpin();
16928 #endif
16929 		counter_u64_add(rack_out_size[TCP_MSS_ACCT_INPACE], 1);
16930 		return (0);
16931 	}
16932 	rack->rc_inp->inp_hpts_calls = 0;
16933 	/* Finish out both pacing early and late accounting */
16934 	if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
16935 	    TSTMP_GT(rack->r_ctl.rc_last_output_to, cts)) {
16936 		early = rack->r_ctl.rc_last_output_to - cts;
16937 	} else
16938 		early = 0;
16939 	if (delayed) {
16940 		rack->r_ctl.rc_agg_delayed += delayed;
16941 		rack->r_late = 1;
16942 	} else if (early) {
16943 		rack->r_ctl.rc_agg_early += early;
16944 		rack->r_early = 1;
16945 	}
16946 	/* Now that early/late accounting is done turn off the flag */
16947 	rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
16948 	rack->r_wanted_output = 0;
16949 	rack->r_timer_override = 0;
16950 	if ((tp->t_state != rack->r_state) &&
16951 	    TCPS_HAVEESTABLISHED(tp->t_state)) {
16952 		rack_set_state(tp, rack);
16953 	}
16954 	if ((rack->r_fast_output) &&
16955 	    (doing_tlp == 0) &&
16956 	    (tp->rcv_numsacks == 0)) {
16957 		int ret;
16958 
16959 		error = 0;
16960 		ret = rack_fast_output(tp, rack, ts_val, cts, ms_cts, &tv, tot_len_this_send, &error);
16961 		if (ret >= 0)
16962 			return(ret);
16963 		else if (error) {
16964 			inp = rack->rc_inp;
16965 			so = inp->inp_socket;
16966 			sb = &so->so_snd;
16967 			goto nomore;
16968 		}
16969 	}
16970 	inp = rack->rc_inp;
16971 	/*
16972 	 * For TFO connections in SYN_SENT or SYN_RECEIVED,
16973 	 * only allow the initial SYN or SYN|ACK and those sent
16974 	 * by the retransmit timer.
16975 	 */
16976 	if (IS_FASTOPEN(tp->t_flags) &&
16977 	    ((tp->t_state == TCPS_SYN_RECEIVED) ||
16978 	     (tp->t_state == TCPS_SYN_SENT)) &&
16979 	    SEQ_GT(tp->snd_max, tp->snd_una) && /* initial SYN or SYN|ACK sent */
16980 	    (tp->t_rxtshift == 0)) {              /* not a retransmit */
16981 		cwnd_to_use = rack->r_ctl.cwnd_to_use = tp->snd_cwnd;
16982 		so = inp->inp_socket;
16983 		sb = &so->so_snd;
16984 		goto just_return_nolock;
16985 	}
16986 	/*
16987 	 * Determine length of data that should be transmitted, and flags
16988 	 * that will be used. If there is some data or critical controls
16989 	 * (SYN, RST) to send, then transmit; otherwise, investigate
16990 	 * further.
16991 	 */
16992 	idle = (tp->t_flags & TF_LASTIDLE) || (tp->snd_max == tp->snd_una);
16993 	if (tp->t_idle_reduce) {
16994 		if (idle && ((ticks - tp->t_rcvtime) >= tp->t_rxtcur))
16995 			rack_cc_after_idle(rack, tp);
16996 	}
16997 	tp->t_flags &= ~TF_LASTIDLE;
16998 	if (idle) {
16999 		if (tp->t_flags & TF_MORETOCOME) {
17000 			tp->t_flags |= TF_LASTIDLE;
17001 			idle = 0;
17002 		}
17003 	}
17004 	if ((tp->snd_una == tp->snd_max) &&
17005 	    rack->r_ctl.rc_went_idle_time &&
17006 	    TSTMP_GT(cts, rack->r_ctl.rc_went_idle_time)) {
17007 		idle = cts - rack->r_ctl.rc_went_idle_time;
17008 		if (idle > rack_min_probertt_hold) {
17009 			/* Count as a probe rtt */
17010 			if (rack->in_probe_rtt == 0) {
17011 				rack->r_ctl.rc_lower_rtt_us_cts = cts;
17012 				rack->r_ctl.rc_time_probertt_entered = rack->r_ctl.rc_lower_rtt_us_cts;
17013 				rack->r_ctl.rc_time_probertt_starts = rack->r_ctl.rc_lower_rtt_us_cts;
17014 				rack->r_ctl.rc_time_of_last_probertt = rack->r_ctl.rc_lower_rtt_us_cts;
17015 			} else {
17016 				rack_exit_probertt(rack, cts);
17017 			}
17018 		}
17019 		idle = 0;
17020 	}
17021 	if (rack_use_fsb && (rack->r_fsb_inited == 0) && (rack->r_state != TCPS_CLOSED))
17022 		rack_init_fsb_block(tp, rack);
17023 again:
17024 	/*
17025 	 * If we've recently taken a timeout, snd_max will be greater than
17026 	 * snd_nxt.  There may be SACK information that allows us to avoid
17027 	 * resending already delivered data.  Adjust snd_nxt accordingly.
17028 	 */
17029 	sendalot = 0;
17030 	cts = tcp_get_usecs(&tv);
17031 	ms_cts = tcp_tv_to_mssectick(&tv);
17032 	tso = 0;
17033 	mtu = 0;
17034 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
17035 	minseg = segsiz;
17036 	if (rack->r_ctl.rc_pace_max_segs == 0)
17037 		pace_max_seg = rack->rc_user_set_max_segs * segsiz;
17038 	else
17039 		pace_max_seg = rack->r_ctl.rc_pace_max_segs;
17040 	sb_offset = tp->snd_max - tp->snd_una;
17041 	cwnd_to_use = rack->r_ctl.cwnd_to_use = tp->snd_cwnd;
17042 	flags = tcp_outflags[tp->t_state];
17043 	while (rack->rc_free_cnt < rack_free_cache) {
17044 		rsm = rack_alloc(rack);
17045 		if (rsm == NULL) {
17046 			if (inp->inp_hpts_calls)
17047 				/* Retry in a ms */
17048 				slot = (1 * HPTS_USEC_IN_MSEC);
17049 			so = inp->inp_socket;
17050 			sb = &so->so_snd;
17051 			goto just_return_nolock;
17052 		}
17053 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_free, rsm, r_tnext);
17054 		rack->rc_free_cnt++;
17055 		rsm = NULL;
17056 	}
17057 	if (inp->inp_hpts_calls)
17058 		inp->inp_hpts_calls = 0;
17059 	sack_rxmit = 0;
17060 	len = 0;
17061 	rsm = NULL;
17062 	if (flags & TH_RST) {
17063 		SOCKBUF_LOCK(&inp->inp_socket->so_snd);
17064 		so = inp->inp_socket;
17065 		sb = &so->so_snd;
17066 		goto send;
17067 	}
17068 	if (rack->r_ctl.rc_resend) {
17069 		/* Retransmit timer */
17070 		rsm = rack->r_ctl.rc_resend;
17071 		rack->r_ctl.rc_resend = NULL;
17072 		len = rsm->r_end - rsm->r_start;
17073 		sack_rxmit = 1;
17074 		sendalot = 0;
17075 		KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start),
17076 			("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p",
17077 			 __func__, __LINE__,
17078 			 rsm->r_start, tp->snd_una, tp, rack, rsm));
17079 		sb_offset = rsm->r_start - tp->snd_una;
17080 		if (len >= segsiz)
17081 			len = segsiz;
17082 	} else if ((rsm = tcp_rack_output(tp, rack, cts)) != NULL) {
17083 		/* We have a retransmit that takes precedence */
17084 		if ((!IN_FASTRECOVERY(tp->t_flags)) &&
17085 		    ((tp->t_flags & TF_WASFRECOVERY) == 0)) {
17086 			/* Enter recovery if not induced by a time-out */
17087 			rack->r_ctl.rc_rsm_start = rsm->r_start;
17088 			rack->r_ctl.rc_cwnd_at = tp->snd_cwnd;
17089 			rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh;
17090 			rack_cong_signal(tp, CC_NDUPACK, tp->snd_una);
17091 		}
17092 #ifdef INVARIANTS
17093 		if (SEQ_LT(rsm->r_start, tp->snd_una)) {
17094 			panic("Huh, tp:%p rack:%p rsm:%p start:%u < snd_una:%u\n",
17095 			      tp, rack, rsm, rsm->r_start, tp->snd_una);
17096 		}
17097 #endif
17098 		len = rsm->r_end - rsm->r_start;
17099 		KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start),
17100 			("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p",
17101 			 __func__, __LINE__,
17102 			 rsm->r_start, tp->snd_una, tp, rack, rsm));
17103 		sb_offset = rsm->r_start - tp->snd_una;
17104 		sendalot = 0;
17105 		if (len >= segsiz)
17106 			len = segsiz;
17107 		if (len > 0) {
17108 			sack_rxmit = 1;
17109 			KMOD_TCPSTAT_INC(tcps_sack_rexmits);
17110 			KMOD_TCPSTAT_ADD(tcps_sack_rexmit_bytes,
17111 			    min(len, segsiz));
17112 			counter_u64_add(rack_rtm_prr_retran, 1);
17113 		}
17114 	} else if (rack->r_ctl.rc_tlpsend) {
17115 		/* Tail loss probe */
17116 		long cwin;
17117 		long tlen;
17118 
17119 		/*
17120 		 * Check if we can do a TLP with a RACK'd packet
17121 		 * this can happen if we are not doing the rack
17122 		 * cheat and we skipped to a TLP and it
17123 		 * went off.
17124 		 */
17125 		rsm = rack->r_ctl.rc_tlpsend;
17126 		/* We are doing a TLP make sure the flag is preent */
17127 		rsm->r_flags |= RACK_TLP;
17128 		rack->r_ctl.rc_tlpsend = NULL;
17129 		sack_rxmit = 1;
17130 		tlen = rsm->r_end - rsm->r_start;
17131 		if (tlen > segsiz)
17132 			tlen = segsiz;
17133 		KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start),
17134 			("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p",
17135 			 __func__, __LINE__,
17136 			 rsm->r_start, tp->snd_una, tp, rack, rsm));
17137 		sb_offset = rsm->r_start - tp->snd_una;
17138 		cwin = min(tp->snd_wnd, tlen);
17139 		len = cwin;
17140 	}
17141 	if (rack->r_must_retran &&
17142 	    (doing_tlp == 0) &&
17143 	    (rsm == NULL)) {
17144 		/*
17145 		 * Non-Sack and we had a RTO or Sack/non-Sack and a
17146 		 * MTU change, we need to retransmit until we reach
17147 		 * the former snd_max (rack->r_ctl.rc_snd_max_at_rto).
17148 		 */
17149 		if (SEQ_GT(tp->snd_max, tp->snd_una)) {
17150 			int sendwin, flight;
17151 
17152 			sendwin = min(tp->snd_wnd, tp->snd_cwnd);
17153 			flight = ctf_flight_size(tp, rack->r_ctl.rc_out_at_rto);
17154 			if (flight >= sendwin) {
17155 				so = inp->inp_socket;
17156 				sb = &so->so_snd;
17157 				goto just_return_nolock;
17158 			}
17159 			rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
17160 			if (rsm == NULL) {
17161 				/* TSNH */
17162 				rack->r_must_retran = 0;
17163 				rack->r_ctl.rc_out_at_rto = 0;
17164 				rack->r_must_retran = 0;
17165 				so = inp->inp_socket;
17166 				sb = &so->so_snd;
17167 				goto just_return_nolock;
17168 			}
17169 			if ((rsm->r_flags & RACK_MUST_RXT) == 0) {
17170 				/* It does not have the flag, we are done */
17171 				rack->r_must_retran = 0;
17172 				rack->r_ctl.rc_out_at_rto = 0;
17173 			} else {
17174 				sack_rxmit = 1;
17175 				len = rsm->r_end - rsm->r_start;
17176 				sendalot = 0;
17177 				sb_offset = rsm->r_start - tp->snd_una;
17178 				if (len >= segsiz)
17179 					len = segsiz;
17180 				/*
17181 				 * Delay removing the flag RACK_MUST_RXT so
17182 				 * that the fastpath for retransmit will
17183 				 * work with this rsm.
17184 				 */
17185 
17186 			}
17187 		} else {
17188 			/* We must be done if there is nothing outstanding */
17189 			rack->r_must_retran = 0;
17190 			rack->r_ctl.rc_out_at_rto = 0;
17191 		}
17192 	}
17193 	/*
17194 	 * Enforce a connection sendmap count limit if set
17195 	 * as long as we are not retransmiting.
17196 	 */
17197 	if ((rsm == NULL) &&
17198 	    (rack->do_detection == 0) &&
17199 	    (V_tcp_map_entries_limit > 0) &&
17200 	    (rack->r_ctl.rc_num_maps_alloced >= V_tcp_map_entries_limit)) {
17201 		counter_u64_add(rack_to_alloc_limited, 1);
17202 		if (!rack->alloc_limit_reported) {
17203 			rack->alloc_limit_reported = 1;
17204 			counter_u64_add(rack_alloc_limited_conns, 1);
17205 		}
17206 		so = inp->inp_socket;
17207 		sb = &so->so_snd;
17208 		goto just_return_nolock;
17209 	}
17210 	if (rsm && (rsm->r_flags & RACK_HAS_FIN)) {
17211 		/* we are retransmitting the fin */
17212 		len--;
17213 		if (len) {
17214 			/*
17215 			 * When retransmitting data do *not* include the
17216 			 * FIN. This could happen from a TLP probe.
17217 			 */
17218 			flags &= ~TH_FIN;
17219 		}
17220 	}
17221 #ifdef INVARIANTS
17222 	/* For debugging */
17223 	rack->r_ctl.rc_rsm_at_retran = rsm;
17224 #endif
17225 	if (rsm && rack->r_fsb_inited && rack_use_rsm_rfo &&
17226 	    ((rsm->r_flags & RACK_HAS_FIN) == 0)) {
17227 		int ret;
17228 
17229 		ret = rack_fast_rsm_output(tp, rack, rsm, ts_val, cts, ms_cts, &tv, len, doing_tlp);
17230 		if (ret == 0)
17231 			return (0);
17232 	}
17233 	if (rsm && (rsm->r_flags & RACK_MUST_RXT)) {
17234 		/*
17235 		 * Clear the flag in prep for the send
17236 		 * note that if we can't get an mbuf
17237 		 * and fail, we won't retransmit this
17238 		 * rsm but that should be ok (its rare).
17239 		 */
17240 		rsm->r_flags &= ~RACK_MUST_RXT;
17241 	}
17242 	so = inp->inp_socket;
17243 	sb = &so->so_snd;
17244 	if (do_a_prefetch == 0) {
17245 		kern_prefetch(sb, &do_a_prefetch);
17246 		do_a_prefetch = 1;
17247 	}
17248 #ifdef NETFLIX_SHARED_CWND
17249 	if ((tp->t_flags2 & TF2_TCP_SCWND_ALLOWED) &&
17250 	    rack->rack_enable_scwnd) {
17251 		/* We are doing cwnd sharing */
17252 		if (rack->gp_ready &&
17253 		    (rack->rack_attempted_scwnd == 0) &&
17254 		    (rack->r_ctl.rc_scw == NULL) &&
17255 		    tp->t_lib) {
17256 			/* The pcbid is in, lets make an attempt */
17257 			counter_u64_add(rack_try_scwnd, 1);
17258 			rack->rack_attempted_scwnd = 1;
17259 			rack->r_ctl.rc_scw = tcp_shared_cwnd_alloc(tp,
17260 								   &rack->r_ctl.rc_scw_index,
17261 								   segsiz);
17262 		}
17263 		if (rack->r_ctl.rc_scw &&
17264 		    (rack->rack_scwnd_is_idle == 1) &&
17265 		    sbavail(&so->so_snd)) {
17266 			/* we are no longer out of data */
17267 			tcp_shared_cwnd_active(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
17268 			rack->rack_scwnd_is_idle = 0;
17269 		}
17270 		if (rack->r_ctl.rc_scw) {
17271 			/* First lets update and get the cwnd */
17272 			rack->r_ctl.cwnd_to_use = cwnd_to_use = tcp_shared_cwnd_update(rack->r_ctl.rc_scw,
17273 								    rack->r_ctl.rc_scw_index,
17274 								    tp->snd_cwnd, tp->snd_wnd, segsiz);
17275 		}
17276 	}
17277 #endif
17278 	/*
17279 	 * Get standard flags, and add SYN or FIN if requested by 'hidden'
17280 	 * state flags.
17281 	 */
17282 	if (tp->t_flags & TF_NEEDFIN)
17283 		flags |= TH_FIN;
17284 	if (tp->t_flags & TF_NEEDSYN)
17285 		flags |= TH_SYN;
17286 	if ((sack_rxmit == 0) && (prefetch_rsm == 0)) {
17287 		void *end_rsm;
17288 		end_rsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_tmap, rack_sendmap, r_tnext);
17289 		if (end_rsm)
17290 			kern_prefetch(end_rsm, &prefetch_rsm);
17291 		prefetch_rsm = 1;
17292 	}
17293 	SOCKBUF_LOCK(sb);
17294 	/*
17295 	 * If snd_nxt == snd_max and we have transmitted a FIN, the
17296 	 * sb_offset will be > 0 even if so_snd.sb_cc is 0, resulting in a
17297 	 * negative length.  This can also occur when TCP opens up its
17298 	 * congestion window while receiving additional duplicate acks after
17299 	 * fast-retransmit because TCP will reset snd_nxt to snd_max after
17300 	 * the fast-retransmit.
17301 	 *
17302 	 * In the normal retransmit-FIN-only case, however, snd_nxt will be
17303 	 * set to snd_una, the sb_offset will be 0, and the length may wind
17304 	 * up 0.
17305 	 *
17306 	 * If sack_rxmit is true we are retransmitting from the scoreboard
17307 	 * in which case len is already set.
17308 	 */
17309 	if ((sack_rxmit == 0) &&
17310 	    (TCPS_HAVEESTABLISHED(tp->t_state) || IS_FASTOPEN(tp->t_flags))) {
17311 		uint32_t avail;
17312 
17313 		avail = sbavail(sb);
17314 		if (SEQ_GT(tp->snd_nxt, tp->snd_una) && avail)
17315 			sb_offset = tp->snd_nxt - tp->snd_una;
17316 		else
17317 			sb_offset = 0;
17318 		if ((IN_FASTRECOVERY(tp->t_flags) == 0) || rack->rack_no_prr) {
17319 			if (rack->r_ctl.rc_tlp_new_data) {
17320 				/* TLP is forcing out new data */
17321 				if (rack->r_ctl.rc_tlp_new_data > (uint32_t) (avail - sb_offset)) {
17322 					rack->r_ctl.rc_tlp_new_data = (uint32_t) (avail - sb_offset);
17323 				}
17324 				if ((rack->r_ctl.rc_tlp_new_data + sb_offset) > tp->snd_wnd) {
17325 					if (tp->snd_wnd > sb_offset)
17326 						len = tp->snd_wnd - sb_offset;
17327 					else
17328 						len = 0;
17329 				} else {
17330 					len = rack->r_ctl.rc_tlp_new_data;
17331 				}
17332 				rack->r_ctl.rc_tlp_new_data = 0;
17333 			}  else {
17334 				len = rack_what_can_we_send(tp, rack, cwnd_to_use, avail, sb_offset);
17335 			}
17336 			if ((rack->r_ctl.crte == NULL) && IN_FASTRECOVERY(tp->t_flags) && (len > segsiz)) {
17337 				/*
17338 				 * For prr=off, we need to send only 1 MSS
17339 				 * at a time. We do this because another sack could
17340 				 * be arriving that causes us to send retransmits and
17341 				 * we don't want to be on a long pace due to a larger send
17342 				 * that keeps us from sending out the retransmit.
17343 				 */
17344 				len = segsiz;
17345 			}
17346 		} else {
17347 			uint32_t outstanding;
17348 			/*
17349 			 * We are inside of a Fast recovery episode, this
17350 			 * is caused by a SACK or 3 dup acks. At this point
17351 			 * we have sent all the retransmissions and we rely
17352 			 * on PRR to dictate what we will send in the form of
17353 			 * new data.
17354 			 */
17355 
17356 			outstanding = tp->snd_max - tp->snd_una;
17357 			if ((rack->r_ctl.rc_prr_sndcnt + outstanding) > tp->snd_wnd) {
17358 				if (tp->snd_wnd > outstanding) {
17359 					len = tp->snd_wnd - outstanding;
17360 					/* Check to see if we have the data */
17361 					if ((sb_offset + len) > avail) {
17362 						/* It does not all fit */
17363 						if (avail > sb_offset)
17364 							len = avail - sb_offset;
17365 						else
17366 							len = 0;
17367 					}
17368 				} else {
17369 					len = 0;
17370 				}
17371 			} else if (avail > sb_offset) {
17372 				len = avail - sb_offset;
17373 			} else {
17374 				len = 0;
17375 			}
17376 			if (len > 0) {
17377 				if (len > rack->r_ctl.rc_prr_sndcnt) {
17378 					len = rack->r_ctl.rc_prr_sndcnt;
17379 				}
17380 				if (len > 0) {
17381 					sub_from_prr = 1;
17382 					counter_u64_add(rack_rtm_prr_newdata, 1);
17383 				}
17384 			}
17385 			if (len > segsiz) {
17386 				/*
17387 				 * We should never send more than a MSS when
17388 				 * retransmitting or sending new data in prr
17389 				 * mode unless the override flag is on. Most
17390 				 * likely the PRR algorithm is not going to
17391 				 * let us send a lot as well :-)
17392 				 */
17393 				if (rack->r_ctl.rc_prr_sendalot == 0) {
17394 					len = segsiz;
17395 				}
17396 			} else if (len < segsiz) {
17397 				/*
17398 				 * Do we send any? The idea here is if the
17399 				 * send empty's the socket buffer we want to
17400 				 * do it. However if not then lets just wait
17401 				 * for our prr_sndcnt to get bigger.
17402 				 */
17403 				long leftinsb;
17404 
17405 				leftinsb = sbavail(sb) - sb_offset;
17406 				if (leftinsb > len) {
17407 					/* This send does not empty the sb */
17408 					len = 0;
17409 				}
17410 			}
17411 		}
17412 	} else if (!TCPS_HAVEESTABLISHED(tp->t_state)) {
17413 		/*
17414 		 * If you have not established
17415 		 * and are not doing FAST OPEN
17416 		 * no data please.
17417 		 */
17418 		if ((sack_rxmit == 0) &&
17419 		    (!IS_FASTOPEN(tp->t_flags))){
17420 			len = 0;
17421 			sb_offset = 0;
17422 		}
17423 	}
17424 	if (prefetch_so_done == 0) {
17425 		kern_prefetch(so, &prefetch_so_done);
17426 		prefetch_so_done = 1;
17427 	}
17428 	/*
17429 	 * Lop off SYN bit if it has already been sent.  However, if this is
17430 	 * SYN-SENT state and if segment contains data and if we don't know
17431 	 * that foreign host supports TAO, suppress sending segment.
17432 	 */
17433 	if ((flags & TH_SYN) && SEQ_GT(tp->snd_nxt, tp->snd_una) &&
17434 	    ((sack_rxmit == 0) && (tp->t_rxtshift == 0))) {
17435 		/*
17436 		 * When sending additional segments following a TFO SYN|ACK,
17437 		 * do not include the SYN bit.
17438 		 */
17439 		if (IS_FASTOPEN(tp->t_flags) &&
17440 		    (tp->t_state == TCPS_SYN_RECEIVED))
17441 			flags &= ~TH_SYN;
17442 	}
17443 	/*
17444 	 * Be careful not to send data and/or FIN on SYN segments. This
17445 	 * measure is needed to prevent interoperability problems with not
17446 	 * fully conformant TCP implementations.
17447 	 */
17448 	if ((flags & TH_SYN) && (tp->t_flags & TF_NOOPT)) {
17449 		len = 0;
17450 		flags &= ~TH_FIN;
17451 	}
17452 	/*
17453 	 * On TFO sockets, ensure no data is sent in the following cases:
17454 	 *
17455 	 *  - When retransmitting SYN|ACK on a passively-created socket
17456 	 *
17457 	 *  - When retransmitting SYN on an actively created socket
17458 	 *
17459 	 *  - When sending a zero-length cookie (cookie request) on an
17460 	 *    actively created socket
17461 	 *
17462 	 *  - When the socket is in the CLOSED state (RST is being sent)
17463 	 */
17464 	if (IS_FASTOPEN(tp->t_flags) &&
17465 	    (((flags & TH_SYN) && (tp->t_rxtshift > 0)) ||
17466 	     ((tp->t_state == TCPS_SYN_SENT) &&
17467 	      (tp->t_tfo_client_cookie_len == 0)) ||
17468 	     (flags & TH_RST))) {
17469 		sack_rxmit = 0;
17470 		len = 0;
17471 	}
17472 	/* Without fast-open there should never be data sent on a SYN */
17473 	if ((flags & TH_SYN) && (!IS_FASTOPEN(tp->t_flags))) {
17474 		tp->snd_nxt = tp->iss;
17475 		len = 0;
17476 	}
17477 	if ((len > segsiz) && (tcp_dsack_block_exists(tp))) {
17478 		/* We only send 1 MSS if we have a DSACK block */
17479 		add_flag |= RACK_SENT_W_DSACK;
17480 		len = segsiz;
17481 	}
17482 	orig_len = len;
17483 	if (len <= 0) {
17484 		/*
17485 		 * If FIN has been sent but not acked, but we haven't been
17486 		 * called to retransmit, len will be < 0.  Otherwise, window
17487 		 * shrank after we sent into it.  If window shrank to 0,
17488 		 * cancel pending retransmit, pull snd_nxt back to (closed)
17489 		 * window, and set the persist timer if it isn't already
17490 		 * going.  If the window didn't close completely, just wait
17491 		 * for an ACK.
17492 		 *
17493 		 * We also do a general check here to ensure that we will
17494 		 * set the persist timer when we have data to send, but a
17495 		 * 0-byte window. This makes sure the persist timer is set
17496 		 * even if the packet hits one of the "goto send" lines
17497 		 * below.
17498 		 */
17499 		len = 0;
17500 		if ((tp->snd_wnd == 0) &&
17501 		    (TCPS_HAVEESTABLISHED(tp->t_state)) &&
17502 		    (tp->snd_una == tp->snd_max) &&
17503 		    (sb_offset < (int)sbavail(sb))) {
17504 			rack_enter_persist(tp, rack, cts);
17505 		}
17506 	} else if ((rsm == NULL) &&
17507 		   (doing_tlp == 0) &&
17508 		   (len < pace_max_seg)) {
17509 		/*
17510 		 * We are not sending a maximum sized segment for
17511 		 * some reason. Should we not send anything (think
17512 		 * sws or persists)?
17513 		 */
17514 		if ((tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), minseg)) &&
17515 		    (TCPS_HAVEESTABLISHED(tp->t_state)) &&
17516 		    (len < minseg) &&
17517 		    (len < (int)(sbavail(sb) - sb_offset))) {
17518 			/*
17519 			 * Here the rwnd is less than
17520 			 * the minimum pacing size, this is not a retransmit,
17521 			 * we are established and
17522 			 * the send is not the last in the socket buffer
17523 			 * we send nothing, and we may enter persists
17524 			 * if nothing is outstanding.
17525 			 */
17526 			len = 0;
17527 			if (tp->snd_max == tp->snd_una) {
17528 				/*
17529 				 * Nothing out we can
17530 				 * go into persists.
17531 				 */
17532 				rack_enter_persist(tp, rack, cts);
17533 			}
17534 		     } else if ((cwnd_to_use >= max(minseg, (segsiz * 4))) &&
17535 			   (ctf_flight_size(tp, rack->r_ctl.rc_sacked) > (2 * segsiz)) &&
17536 			   (len < (int)(sbavail(sb) - sb_offset)) &&
17537 			   (len < minseg)) {
17538 			/*
17539 			 * Here we are not retransmitting, and
17540 			 * the cwnd is not so small that we could
17541 			 * not send at least a min size (rxt timer
17542 			 * not having gone off), We have 2 segments or
17543 			 * more already in flight, its not the tail end
17544 			 * of the socket buffer  and the cwnd is blocking
17545 			 * us from sending out a minimum pacing segment size.
17546 			 * Lets not send anything.
17547 			 */
17548 			len = 0;
17549 		} else if (((tp->snd_wnd - ctf_outstanding(tp)) <
17550 			    min((rack->r_ctl.rc_high_rwnd/2), minseg)) &&
17551 			   (ctf_flight_size(tp, rack->r_ctl.rc_sacked) > (2 * segsiz)) &&
17552 			   (len < (int)(sbavail(sb) - sb_offset)) &&
17553 			   (TCPS_HAVEESTABLISHED(tp->t_state))) {
17554 			/*
17555 			 * Here we have a send window but we have
17556 			 * filled it up and we can't send another pacing segment.
17557 			 * We also have in flight more than 2 segments
17558 			 * and we are not completing the sb i.e. we allow
17559 			 * the last bytes of the sb to go out even if
17560 			 * its not a full pacing segment.
17561 			 */
17562 			len = 0;
17563 		} else if ((rack->r_ctl.crte != NULL) &&
17564 			   (tp->snd_wnd >= (pace_max_seg * max(1, rack_hw_rwnd_factor))) &&
17565 			   (cwnd_to_use >= (pace_max_seg + (4 * segsiz))) &&
17566 			   (ctf_flight_size(tp, rack->r_ctl.rc_sacked) >= (2 * segsiz)) &&
17567 			   (len < (int)(sbavail(sb) - sb_offset))) {
17568 			/*
17569 			 * Here we are doing hardware pacing, this is not a TLP,
17570 			 * we are not sending a pace max segment size, there is rwnd
17571 			 * room to send at least N pace_max_seg, the cwnd is greater
17572 			 * than or equal to a full pacing segments plus 4 mss and we have 2 or
17573 			 * more segments in flight and its not the tail of the socket buffer.
17574 			 *
17575 			 * We don't want to send instead we need to get more ack's in to
17576 			 * allow us to send a full pacing segment. Normally, if we are pacing
17577 			 * about the right speed, we should have finished our pacing
17578 			 * send as most of the acks have come back if we are at the
17579 			 * right rate. This is a bit fuzzy since return path delay
17580 			 * can delay the acks, which is why we want to make sure we
17581 			 * have cwnd space to have a bit more than a max pace segments in flight.
17582 			 *
17583 			 * If we have not gotten our acks back we are pacing at too high a
17584 			 * rate delaying will not hurt and will bring our GP estimate down by
17585 			 * injecting the delay. If we don't do this we will send
17586 			 * 2 MSS out in response to the acks being clocked in which
17587 			 * defeats the point of hw-pacing (i.e. to help us get
17588 			 * larger TSO's out).
17589 			 */
17590 			len = 0;
17591 
17592 		}
17593 
17594 	}
17595 	/* len will be >= 0 after this point. */
17596 	KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__));
17597 	rack_sndbuf_autoscale(rack);
17598 	/*
17599 	 * Decide if we can use TCP Segmentation Offloading (if supported by
17600 	 * hardware).
17601 	 *
17602 	 * TSO may only be used if we are in a pure bulk sending state.  The
17603 	 * presence of TCP-MD5, SACK retransmits, SACK advertizements and IP
17604 	 * options prevent using TSO.  With TSO the TCP header is the same
17605 	 * (except for the sequence number) for all generated packets.  This
17606 	 * makes it impossible to transmit any options which vary per
17607 	 * generated segment or packet.
17608 	 *
17609 	 * IPv4 handling has a clear separation of ip options and ip header
17610 	 * flags while IPv6 combines both in in6p_outputopts. ip6_optlen() does
17611 	 * the right thing below to provide length of just ip options and thus
17612 	 * checking for ipoptlen is enough to decide if ip options are present.
17613 	 */
17614 	ipoptlen = 0;
17615 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
17616 	/*
17617 	 * Pre-calculate here as we save another lookup into the darknesses
17618 	 * of IPsec that way and can actually decide if TSO is ok.
17619 	 */
17620 #ifdef INET6
17621 	if (isipv6 && IPSEC_ENABLED(ipv6))
17622 		ipsec_optlen = IPSEC_HDRSIZE(ipv6, tp->t_inpcb);
17623 #ifdef INET
17624 	else
17625 #endif
17626 #endif				/* INET6 */
17627 #ifdef INET
17628 		if (IPSEC_ENABLED(ipv4))
17629 			ipsec_optlen = IPSEC_HDRSIZE(ipv4, tp->t_inpcb);
17630 #endif				/* INET */
17631 #endif
17632 
17633 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
17634 	ipoptlen += ipsec_optlen;
17635 #endif
17636 	if ((tp->t_flags & TF_TSO) && V_tcp_do_tso && len > segsiz &&
17637 	    (tp->t_port == 0) &&
17638 	    ((tp->t_flags & TF_SIGNATURE) == 0) &&
17639 	    tp->rcv_numsacks == 0 && sack_rxmit == 0 &&
17640 	    ipoptlen == 0)
17641 		tso = 1;
17642 	{
17643 		uint32_t outstanding;
17644 
17645 		outstanding = tp->snd_max - tp->snd_una;
17646 		if (tp->t_flags & TF_SENTFIN) {
17647 			/*
17648 			 * If we sent a fin, snd_max is 1 higher than
17649 			 * snd_una
17650 			 */
17651 			outstanding--;
17652 		}
17653 		if (sack_rxmit) {
17654 			if ((rsm->r_flags & RACK_HAS_FIN) == 0)
17655 				flags &= ~TH_FIN;
17656 		} else {
17657 			if (SEQ_LT(tp->snd_nxt + len, tp->snd_una +
17658 				   sbused(sb)))
17659 				flags &= ~TH_FIN;
17660 		}
17661 	}
17662 	recwin = lmin(lmax(sbspace(&so->so_rcv), 0),
17663 	    (long)TCP_MAXWIN << tp->rcv_scale);
17664 
17665 	/*
17666 	 * Sender silly window avoidance.   We transmit under the following
17667 	 * conditions when len is non-zero:
17668 	 *
17669 	 * - We have a full segment (or more with TSO) - This is the last
17670 	 * buffer in a write()/send() and we are either idle or running
17671 	 * NODELAY - we've timed out (e.g. persist timer) - we have more
17672 	 * then 1/2 the maximum send window's worth of data (receiver may be
17673 	 * limited the window size) - we need to retransmit
17674 	 */
17675 	if (len) {
17676 		if (len >= segsiz) {
17677 			goto send;
17678 		}
17679 		/*
17680 		 * NOTE! on localhost connections an 'ack' from the remote
17681 		 * end may occur synchronously with the output and cause us
17682 		 * to flush a buffer queued with moretocome.  XXX
17683 		 *
17684 		 */
17685 		if (!(tp->t_flags & TF_MORETOCOME) &&	/* normal case */
17686 		    (idle || (tp->t_flags & TF_NODELAY)) &&
17687 		    ((uint32_t)len + (uint32_t)sb_offset >= sbavail(sb)) &&
17688 		    (tp->t_flags & TF_NOPUSH) == 0) {
17689 			pass = 2;
17690 			goto send;
17691 		}
17692 		if ((tp->snd_una == tp->snd_max) && len) {	/* Nothing outstanding */
17693 			pass = 22;
17694 			goto send;
17695 		}
17696 		if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) {
17697 			pass = 4;
17698 			goto send;
17699 		}
17700 		if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {	/* retransmit case */
17701 			pass = 5;
17702 			goto send;
17703 		}
17704 		if (sack_rxmit) {
17705 			pass = 6;
17706 			goto send;
17707 		}
17708 		if (((tp->snd_wnd - ctf_outstanding(tp)) < segsiz) &&
17709 		    (ctf_outstanding(tp) < (segsiz * 2))) {
17710 			/*
17711 			 * We have less than two MSS outstanding (delayed ack)
17712 			 * and our rwnd will not let us send a full sized
17713 			 * MSS. Lets go ahead and let this small segment
17714 			 * out because we want to try to have at least two
17715 			 * packets inflight to not be caught by delayed ack.
17716 			 */
17717 			pass = 12;
17718 			goto send;
17719 		}
17720 	}
17721 	/*
17722 	 * Sending of standalone window updates.
17723 	 *
17724 	 * Window updates are important when we close our window due to a
17725 	 * full socket buffer and are opening it again after the application
17726 	 * reads data from it.  Once the window has opened again and the
17727 	 * remote end starts to send again the ACK clock takes over and
17728 	 * provides the most current window information.
17729 	 *
17730 	 * We must avoid the silly window syndrome whereas every read from
17731 	 * the receive buffer, no matter how small, causes a window update
17732 	 * to be sent.  We also should avoid sending a flurry of window
17733 	 * updates when the socket buffer had queued a lot of data and the
17734 	 * application is doing small reads.
17735 	 *
17736 	 * Prevent a flurry of pointless window updates by only sending an
17737 	 * update when we can increase the advertized window by more than
17738 	 * 1/4th of the socket buffer capacity.  When the buffer is getting
17739 	 * full or is very small be more aggressive and send an update
17740 	 * whenever we can increase by two mss sized segments. In all other
17741 	 * situations the ACK's to new incoming data will carry further
17742 	 * window increases.
17743 	 *
17744 	 * Don't send an independent window update if a delayed ACK is
17745 	 * pending (it will get piggy-backed on it) or the remote side
17746 	 * already has done a half-close and won't send more data.  Skip
17747 	 * this if the connection is in T/TCP half-open state.
17748 	 */
17749 	if (recwin > 0 && !(tp->t_flags & TF_NEEDSYN) &&
17750 	    !(tp->t_flags & TF_DELACK) &&
17751 	    !TCPS_HAVERCVDFIN(tp->t_state)) {
17752 		/*
17753 		 * "adv" is the amount we could increase the window, taking
17754 		 * into account that we are limited by TCP_MAXWIN <<
17755 		 * tp->rcv_scale.
17756 		 */
17757 		int32_t adv;
17758 		int oldwin;
17759 
17760 		adv = recwin;
17761 		if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt)) {
17762 			oldwin = (tp->rcv_adv - tp->rcv_nxt);
17763 			if (adv > oldwin)
17764 			    adv -= oldwin;
17765 			else {
17766 				/* We can't increase the window */
17767 				adv = 0;
17768 			}
17769 		} else
17770 			oldwin = 0;
17771 
17772 		/*
17773 		 * If the new window size ends up being the same as or less
17774 		 * than the old size when it is scaled, then don't force
17775 		 * a window update.
17776 		 */
17777 		if (oldwin >> tp->rcv_scale >= (adv + oldwin) >> tp->rcv_scale)
17778 			goto dontupdate;
17779 
17780 		if (adv >= (int32_t)(2 * segsiz) &&
17781 		    (adv >= (int32_t)(so->so_rcv.sb_hiwat / 4) ||
17782 		     recwin <= (int32_t)(so->so_rcv.sb_hiwat / 8) ||
17783 		     so->so_rcv.sb_hiwat <= 8 * segsiz)) {
17784 			pass = 7;
17785 			goto send;
17786 		}
17787 		if (2 * adv >= (int32_t) so->so_rcv.sb_hiwat) {
17788 			pass = 23;
17789 			goto send;
17790 		}
17791 	}
17792 dontupdate:
17793 
17794 	/*
17795 	 * Send if we owe the peer an ACK, RST, SYN, or urgent data.  ACKNOW
17796 	 * is also a catch-all for the retransmit timer timeout case.
17797 	 */
17798 	if (tp->t_flags & TF_ACKNOW) {
17799 		pass = 8;
17800 		goto send;
17801 	}
17802 	if (((flags & TH_SYN) && (tp->t_flags & TF_NEEDSYN) == 0)) {
17803 		pass = 9;
17804 		goto send;
17805 	}
17806 	/*
17807 	 * If our state indicates that FIN should be sent and we have not
17808 	 * yet done so, then we need to send.
17809 	 */
17810 	if ((flags & TH_FIN) &&
17811 	    (tp->snd_nxt == tp->snd_una)) {
17812 		pass = 11;
17813 		goto send;
17814 	}
17815 	/*
17816 	 * No reason to send a segment, just return.
17817 	 */
17818 just_return:
17819 	SOCKBUF_UNLOCK(sb);
17820 just_return_nolock:
17821 	{
17822 		int app_limited = CTF_JR_SENT_DATA;
17823 
17824 		if (tot_len_this_send > 0) {
17825 			/* Make sure snd_nxt is up to max */
17826 			rack->r_ctl.fsb.recwin = recwin;
17827 			slot = rack_get_pacing_delay(rack, tp, tot_len_this_send, NULL, segsiz);
17828 			if ((error == 0) &&
17829 			    rack_use_rfo &&
17830 			    ((flags & (TH_SYN|TH_FIN)) == 0) &&
17831 			    (ipoptlen == 0) &&
17832 			    (tp->snd_nxt == tp->snd_max) &&
17833 			    (tp->rcv_numsacks == 0) &&
17834 			    rack->r_fsb_inited &&
17835 			    TCPS_HAVEESTABLISHED(tp->t_state) &&
17836 			    (rack->r_must_retran == 0) &&
17837 			    ((tp->t_flags & TF_NEEDFIN) == 0) &&
17838 			    (len > 0) && (orig_len > 0) &&
17839 			    (orig_len > len) &&
17840 			    ((orig_len - len) >= segsiz) &&
17841 			    ((optlen == 0) ||
17842 			     ((optlen == TCPOLEN_TSTAMP_APPA) && (to.to_flags & TOF_TS)))) {
17843 				/* We can send at least one more MSS using our fsb */
17844 
17845 				rack->r_fast_output = 1;
17846 				rack->r_ctl.fsb.m = sbsndmbuf(sb, (tp->snd_max - tp->snd_una), &rack->r_ctl.fsb.off);
17847 				rack->r_ctl.fsb.o_m_len = rack->r_ctl.fsb.m->m_len;
17848 				rack->r_ctl.fsb.tcp_flags = flags;
17849 				rack->r_ctl.fsb.left_to_send = orig_len - len;
17850 				if (hw_tls)
17851 					rack->r_ctl.fsb.hw_tls = 1;
17852 				else
17853 					rack->r_ctl.fsb.hw_tls = 0;
17854 				KASSERT((rack->r_ctl.fsb.left_to_send <= (sbavail(sb) - (tp->snd_max - tp->snd_una))),
17855 					("rack:%p left_to_send:%u sbavail:%u out:%u",
17856 					rack, rack->r_ctl.fsb.left_to_send, sbavail(sb),
17857 					 (tp->snd_max - tp->snd_una)));
17858 				if (rack->r_ctl.fsb.left_to_send < segsiz)
17859 					rack->r_fast_output = 0;
17860 				else {
17861 					if (rack->r_ctl.fsb.left_to_send == (sbavail(sb) - (tp->snd_max - tp->snd_una)))
17862 						rack->r_ctl.fsb.rfo_apply_push = 1;
17863 					else
17864 						rack->r_ctl.fsb.rfo_apply_push = 0;
17865 				}
17866 			} else
17867 				rack->r_fast_output = 0;
17868 
17869 
17870 			rack_log_fsb(rack, tp, so, flags,
17871 				     ipoptlen, orig_len, len, 0,
17872 				     1, optlen, __LINE__, 1);
17873 			if (SEQ_GT(tp->snd_max, tp->snd_nxt))
17874 				tp->snd_nxt = tp->snd_max;
17875 		} else {
17876 			int end_window = 0;
17877 			uint32_t seq = tp->gput_ack;
17878 
17879 			rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
17880 			if (rsm) {
17881 				/*
17882 				 * Mark the last sent that we just-returned (hinting
17883 				 * that delayed ack may play a role in any rtt measurement).
17884 				 */
17885 				rsm->r_just_ret = 1;
17886 			}
17887 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_JUSTRET], 1);
17888 			rack->r_ctl.rc_agg_delayed = 0;
17889 			rack->r_early = 0;
17890 			rack->r_late = 0;
17891 			rack->r_ctl.rc_agg_early = 0;
17892 			if ((ctf_outstanding(tp) +
17893 			     min(max(segsiz, (rack->r_ctl.rc_high_rwnd/2)),
17894 				 minseg)) >= tp->snd_wnd) {
17895 				/* We are limited by the rwnd */
17896 				app_limited = CTF_JR_RWND_LIMITED;
17897 				if (IN_FASTRECOVERY(tp->t_flags))
17898 				    rack->r_ctl.rc_prr_sndcnt = 0;
17899 			} else if (ctf_outstanding(tp) >= sbavail(sb)) {
17900 				/* We are limited by whats available -- app limited */
17901 				app_limited = CTF_JR_APP_LIMITED;
17902 				if (IN_FASTRECOVERY(tp->t_flags))
17903 				    rack->r_ctl.rc_prr_sndcnt = 0;
17904 			} else if ((idle == 0) &&
17905 				   ((tp->t_flags & TF_NODELAY) == 0) &&
17906 				   ((uint32_t)len + (uint32_t)sb_offset >= sbavail(sb)) &&
17907 				   (len < segsiz)) {
17908 				/*
17909 				 * No delay is not on and the
17910 				 * user is sending less than 1MSS. This
17911 				 * brings out SWS avoidance so we
17912 				 * don't send. Another app-limited case.
17913 				 */
17914 				app_limited = CTF_JR_APP_LIMITED;
17915 			} else if (tp->t_flags & TF_NOPUSH) {
17916 				/*
17917 				 * The user has requested no push of
17918 				 * the last segment and we are
17919 				 * at the last segment. Another app
17920 				 * limited case.
17921 				 */
17922 				app_limited = CTF_JR_APP_LIMITED;
17923 			} else if ((ctf_outstanding(tp) + minseg) > cwnd_to_use) {
17924 				/* Its the cwnd */
17925 				app_limited = CTF_JR_CWND_LIMITED;
17926 			} else if (IN_FASTRECOVERY(tp->t_flags) &&
17927 				   (rack->rack_no_prr == 0) &&
17928 				   (rack->r_ctl.rc_prr_sndcnt < segsiz)) {
17929 				app_limited = CTF_JR_PRR;
17930 			} else {
17931 				/* Now why here are we not sending? */
17932 #ifdef NOW
17933 #ifdef INVARIANTS
17934 				panic("rack:%p hit JR_ASSESSING case cwnd_to_use:%u?", rack, cwnd_to_use);
17935 #endif
17936 #endif
17937 				app_limited = CTF_JR_ASSESSING;
17938 			}
17939 			/*
17940 			 * App limited in some fashion, for our pacing GP
17941 			 * measurements we don't want any gap (even cwnd).
17942 			 * Close  down the measurement window.
17943 			 */
17944 			if (rack_cwnd_block_ends_measure &&
17945 			    ((app_limited == CTF_JR_CWND_LIMITED) ||
17946 			     (app_limited == CTF_JR_PRR))) {
17947 				/*
17948 				 * The reason we are not sending is
17949 				 * the cwnd (or prr). We have been configured
17950 				 * to end the measurement window in
17951 				 * this case.
17952 				 */
17953 				end_window = 1;
17954 			} else if (rack_rwnd_block_ends_measure &&
17955 				   (app_limited == CTF_JR_RWND_LIMITED)) {
17956 				/*
17957 				 * We are rwnd limited and have been
17958 				 * configured to end the measurement
17959 				 * window in this case.
17960 				 */
17961 				end_window = 1;
17962 			} else if (app_limited == CTF_JR_APP_LIMITED) {
17963 				/*
17964 				 * A true application limited period, we have
17965 				 * ran out of data.
17966 				 */
17967 				end_window = 1;
17968 			} else if (app_limited == CTF_JR_ASSESSING) {
17969 				/*
17970 				 * In the assessing case we hit the end of
17971 				 * the if/else and had no known reason
17972 				 * This will panic us under invariants..
17973 				 *
17974 				 * If we get this out in logs we need to
17975 				 * investagate which reason we missed.
17976 				 */
17977 				end_window = 1;
17978 			}
17979 			if (end_window) {
17980 				uint8_t log = 0;
17981 
17982 				/* Adjust the Gput measurement */
17983 				if ((tp->t_flags & TF_GPUTINPROG) &&
17984 				    SEQ_GT(tp->gput_ack, tp->snd_max)) {
17985 					tp->gput_ack = tp->snd_max;
17986 					if ((tp->gput_ack - tp->gput_seq) < (MIN_GP_WIN * segsiz)) {
17987 						/*
17988 						 * There is not enough to measure.
17989 						 */
17990 						tp->t_flags &= ~TF_GPUTINPROG;
17991 						rack_log_pacing_delay_calc(rack, (tp->gput_ack - tp->gput_seq) /*flex2*/,
17992 									   rack->r_ctl.rc_gp_srtt /*flex1*/,
17993 									   tp->gput_seq,
17994 									   0, 0, 18, __LINE__, NULL, 0);
17995 					} else
17996 						log = 1;
17997 				}
17998 				/* Mark the last packet has app limited */
17999 				rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
18000 				if (rsm && ((rsm->r_flags & RACK_APP_LIMITED) == 0)) {
18001 					if (rack->r_ctl.rc_app_limited_cnt == 0)
18002 						rack->r_ctl.rc_end_appl = rack->r_ctl.rc_first_appl = rsm;
18003 					else {
18004 						/*
18005 						 * Go out to the end app limited and mark
18006 						 * this new one as next and move the end_appl up
18007 						 * to this guy.
18008 						 */
18009 						if (rack->r_ctl.rc_end_appl)
18010 							rack->r_ctl.rc_end_appl->r_nseq_appl = rsm->r_start;
18011 						rack->r_ctl.rc_end_appl = rsm;
18012 					}
18013 					rsm->r_flags |= RACK_APP_LIMITED;
18014 					rack->r_ctl.rc_app_limited_cnt++;
18015 				}
18016 				if (log)
18017 					rack_log_pacing_delay_calc(rack,
18018 								   rack->r_ctl.rc_app_limited_cnt, seq,
18019 								   tp->gput_ack, 0, 0, 4, __LINE__, NULL, 0);
18020 			}
18021 		}
18022 		if (slot) {
18023 			/* set the rack tcb into the slot N */
18024 			counter_u64_add(rack_paced_segments, 1);
18025 		} else if (tot_len_this_send) {
18026 			counter_u64_add(rack_unpaced_segments, 1);
18027 		}
18028 		/* Check if we need to go into persists or not */
18029 		if ((tp->snd_max == tp->snd_una) &&
18030 		    TCPS_HAVEESTABLISHED(tp->t_state) &&
18031 		    sbavail(sb) &&
18032 		    (sbavail(sb) > tp->snd_wnd) &&
18033 		    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), minseg))) {
18034 			/* Yes lets make sure to move to persist before timer-start */
18035 			rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
18036 		}
18037 		rack_start_hpts_timer(rack, tp, cts, slot, tot_len_this_send, sup_rack);
18038 		rack_log_type_just_return(rack, cts, tot_len_this_send, slot, hpts_calling, app_limited, cwnd_to_use);
18039 	}
18040 #ifdef NETFLIX_SHARED_CWND
18041 	if ((sbavail(sb) == 0) &&
18042 	    rack->r_ctl.rc_scw) {
18043 		tcp_shared_cwnd_idle(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
18044 		rack->rack_scwnd_is_idle = 1;
18045 	}
18046 #endif
18047 #ifdef TCP_ACCOUNTING
18048 	if (tot_len_this_send > 0) {
18049 		crtsc = get_cyclecount();
18050 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
18051 			tp->tcp_cnt_counters[SND_OUT_DATA]++;
18052 		}
18053 		counter_u64_add(tcp_cnt_counters[SND_OUT_DATA], 1);
18054 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
18055 			tp->tcp_proc_time[SND_OUT_DATA] += (crtsc - ts_val);
18056 		}
18057 		counter_u64_add(tcp_proc_time[SND_OUT_DATA], (crtsc - ts_val));
18058 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
18059 			tp->tcp_cnt_counters[CNT_OF_MSS_OUT] += ((tot_len_this_send + segsiz - 1) / segsiz);
18060 		}
18061 		counter_u64_add(tcp_cnt_counters[CNT_OF_MSS_OUT], ((tot_len_this_send + segsiz - 1) / segsiz));
18062 	} else {
18063 		crtsc = get_cyclecount();
18064 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
18065 			tp->tcp_cnt_counters[SND_LIMITED]++;
18066 		}
18067 		counter_u64_add(tcp_cnt_counters[SND_LIMITED], 1);
18068 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
18069 			tp->tcp_proc_time[SND_LIMITED] += (crtsc - ts_val);
18070 		}
18071 		counter_u64_add(tcp_proc_time[SND_LIMITED], (crtsc - ts_val));
18072 	}
18073 	sched_unpin();
18074 #endif
18075 	return (0);
18076 
18077 send:
18078 	if (rsm || sack_rxmit)
18079 		counter_u64_add(rack_nfto_resend, 1);
18080 	else
18081 		counter_u64_add(rack_non_fto_send, 1);
18082 	if ((flags & TH_FIN) &&
18083 	    sbavail(sb)) {
18084 		/*
18085 		 * We do not transmit a FIN
18086 		 * with data outstanding. We
18087 		 * need to make it so all data
18088 		 * is acked first.
18089 		 */
18090 		flags &= ~TH_FIN;
18091 	}
18092 	/* Enforce stack imposed max seg size if we have one */
18093 	if (rack->r_ctl.rc_pace_max_segs &&
18094 	    (len > rack->r_ctl.rc_pace_max_segs)) {
18095 		mark = 1;
18096 		len = rack->r_ctl.rc_pace_max_segs;
18097 	}
18098 	SOCKBUF_LOCK_ASSERT(sb);
18099 	if (len > 0) {
18100 		if (len >= segsiz)
18101 			tp->t_flags2 |= TF2_PLPMTU_MAXSEGSNT;
18102 		else
18103 			tp->t_flags2 &= ~TF2_PLPMTU_MAXSEGSNT;
18104 	}
18105 	/*
18106 	 * Before ESTABLISHED, force sending of initial options unless TCP
18107 	 * set not to do any options. NOTE: we assume that the IP/TCP header
18108 	 * plus TCP options always fit in a single mbuf, leaving room for a
18109 	 * maximum link header, i.e. max_linkhdr + sizeof (struct tcpiphdr)
18110 	 * + optlen <= MCLBYTES
18111 	 */
18112 	optlen = 0;
18113 #ifdef INET6
18114 	if (isipv6)
18115 		hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
18116 	else
18117 #endif
18118 		hdrlen = sizeof(struct tcpiphdr);
18119 
18120 	/*
18121 	 * Compute options for segment. We only have to care about SYN and
18122 	 * established connection segments.  Options for SYN-ACK segments
18123 	 * are handled in TCP syncache.
18124 	 */
18125 	to.to_flags = 0;
18126 	if ((tp->t_flags & TF_NOOPT) == 0) {
18127 		/* Maximum segment size. */
18128 		if (flags & TH_SYN) {
18129 			tp->snd_nxt = tp->iss;
18130 			to.to_mss = tcp_mssopt(&inp->inp_inc);
18131 			if (tp->t_port)
18132 				to.to_mss -= V_tcp_udp_tunneling_overhead;
18133 			to.to_flags |= TOF_MSS;
18134 
18135 			/*
18136 			 * On SYN or SYN|ACK transmits on TFO connections,
18137 			 * only include the TFO option if it is not a
18138 			 * retransmit, as the presence of the TFO option may
18139 			 * have caused the original SYN or SYN|ACK to have
18140 			 * been dropped by a middlebox.
18141 			 */
18142 			if (IS_FASTOPEN(tp->t_flags) &&
18143 			    (tp->t_rxtshift == 0)) {
18144 				if (tp->t_state == TCPS_SYN_RECEIVED) {
18145 					to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN;
18146 					to.to_tfo_cookie =
18147 						(u_int8_t *)&tp->t_tfo_cookie.server;
18148 					to.to_flags |= TOF_FASTOPEN;
18149 					wanted_cookie = 1;
18150 				} else if (tp->t_state == TCPS_SYN_SENT) {
18151 					to.to_tfo_len =
18152 						tp->t_tfo_client_cookie_len;
18153 					to.to_tfo_cookie =
18154 						tp->t_tfo_cookie.client;
18155 					to.to_flags |= TOF_FASTOPEN;
18156 					wanted_cookie = 1;
18157 					/*
18158 					 * If we wind up having more data to
18159 					 * send with the SYN than can fit in
18160 					 * one segment, don't send any more
18161 					 * until the SYN|ACK comes back from
18162 					 * the other end.
18163 					 */
18164 					sendalot = 0;
18165 				}
18166 			}
18167 		}
18168 		/* Window scaling. */
18169 		if ((flags & TH_SYN) && (tp->t_flags & TF_REQ_SCALE)) {
18170 			to.to_wscale = tp->request_r_scale;
18171 			to.to_flags |= TOF_SCALE;
18172 		}
18173 		/* Timestamps. */
18174 		if ((tp->t_flags & TF_RCVD_TSTMP) ||
18175 		    ((flags & TH_SYN) && (tp->t_flags & TF_REQ_TSTMP))) {
18176 			to.to_tsval = ms_cts + tp->ts_offset;
18177 			to.to_tsecr = tp->ts_recent;
18178 			to.to_flags |= TOF_TS;
18179 		}
18180 		/* Set receive buffer autosizing timestamp. */
18181 		if (tp->rfbuf_ts == 0 &&
18182 		    (so->so_rcv.sb_flags & SB_AUTOSIZE))
18183 			tp->rfbuf_ts = tcp_ts_getticks();
18184 		/* Selective ACK's. */
18185 		if (tp->t_flags & TF_SACK_PERMIT) {
18186 			if (flags & TH_SYN)
18187 				to.to_flags |= TOF_SACKPERM;
18188 			else if (TCPS_HAVEESTABLISHED(tp->t_state) &&
18189 				 tp->rcv_numsacks > 0) {
18190 				to.to_flags |= TOF_SACK;
18191 				to.to_nsacks = tp->rcv_numsacks;
18192 				to.to_sacks = (u_char *)tp->sackblks;
18193 			}
18194 		}
18195 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
18196 		/* TCP-MD5 (RFC2385). */
18197 		if (tp->t_flags & TF_SIGNATURE)
18198 			to.to_flags |= TOF_SIGNATURE;
18199 #endif				/* TCP_SIGNATURE */
18200 
18201 		/* Processing the options. */
18202 		hdrlen += optlen = tcp_addoptions(&to, opt);
18203 		/*
18204 		 * If we wanted a TFO option to be added, but it was unable
18205 		 * to fit, ensure no data is sent.
18206 		 */
18207 		if (IS_FASTOPEN(tp->t_flags) && wanted_cookie &&
18208 		    !(to.to_flags & TOF_FASTOPEN))
18209 			len = 0;
18210 	}
18211 	if (tp->t_port) {
18212 		if (V_tcp_udp_tunneling_port == 0) {
18213 			/* The port was removed?? */
18214 			SOCKBUF_UNLOCK(&so->so_snd);
18215 #ifdef TCP_ACCOUNTING
18216 			crtsc = get_cyclecount();
18217 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
18218 				tp->tcp_cnt_counters[SND_OUT_FAIL]++;
18219 			}
18220 			counter_u64_add(tcp_cnt_counters[SND_OUT_FAIL], 1);
18221 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
18222 				tp->tcp_proc_time[SND_OUT_FAIL] += (crtsc - ts_val);
18223 			}
18224 			counter_u64_add(tcp_proc_time[SND_OUT_FAIL], (crtsc - ts_val));
18225 			sched_unpin();
18226 #endif
18227 			return (EHOSTUNREACH);
18228 		}
18229 		hdrlen += sizeof(struct udphdr);
18230 	}
18231 #ifdef INET6
18232 	if (isipv6)
18233 		ipoptlen = ip6_optlen(tp->t_inpcb);
18234 	else
18235 #endif
18236 		if (tp->t_inpcb->inp_options)
18237 			ipoptlen = tp->t_inpcb->inp_options->m_len -
18238 				offsetof(struct ipoption, ipopt_list);
18239 		else
18240 			ipoptlen = 0;
18241 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
18242 	ipoptlen += ipsec_optlen;
18243 #endif
18244 
18245 	/*
18246 	 * Adjust data length if insertion of options will bump the packet
18247 	 * length beyond the t_maxseg length. Clear the FIN bit because we
18248 	 * cut off the tail of the segment.
18249 	 */
18250 	if (len + optlen + ipoptlen > tp->t_maxseg) {
18251 		if (tso) {
18252 			uint32_t if_hw_tsomax;
18253 			uint32_t moff;
18254 			int32_t max_len;
18255 
18256 			/* extract TSO information */
18257 			if_hw_tsomax = tp->t_tsomax;
18258 			if_hw_tsomaxsegcount = tp->t_tsomaxsegcount;
18259 			if_hw_tsomaxsegsize = tp->t_tsomaxsegsize;
18260 			KASSERT(ipoptlen == 0,
18261 				("%s: TSO can't do IP options", __func__));
18262 
18263 			/*
18264 			 * Check if we should limit by maximum payload
18265 			 * length:
18266 			 */
18267 			if (if_hw_tsomax != 0) {
18268 				/* compute maximum TSO length */
18269 				max_len = (if_hw_tsomax - hdrlen -
18270 					   max_linkhdr);
18271 				if (max_len <= 0) {
18272 					len = 0;
18273 				} else if (len > max_len) {
18274 					sendalot = 1;
18275 					len = max_len;
18276 					mark = 2;
18277 				}
18278 			}
18279 			/*
18280 			 * Prevent the last segment from being fractional
18281 			 * unless the send sockbuf can be emptied:
18282 			 */
18283 			max_len = (tp->t_maxseg - optlen);
18284 			if ((sb_offset + len) < sbavail(sb)) {
18285 				moff = len % (u_int)max_len;
18286 				if (moff != 0) {
18287 					mark = 3;
18288 					len -= moff;
18289 				}
18290 			}
18291 			/*
18292 			 * In case there are too many small fragments don't
18293 			 * use TSO:
18294 			 */
18295 			if (len <= segsiz) {
18296 				mark = 4;
18297 				tso = 0;
18298 			}
18299 			/*
18300 			 * Send the FIN in a separate segment after the bulk
18301 			 * sending is done. We don't trust the TSO
18302 			 * implementations to clear the FIN flag on all but
18303 			 * the last segment.
18304 			 */
18305 			if (tp->t_flags & TF_NEEDFIN) {
18306 				sendalot = 4;
18307 			}
18308 		} else {
18309 			mark = 5;
18310 			if (optlen + ipoptlen >= tp->t_maxseg) {
18311 				/*
18312 				 * Since we don't have enough space to put
18313 				 * the IP header chain and the TCP header in
18314 				 * one packet as required by RFC 7112, don't
18315 				 * send it. Also ensure that at least one
18316 				 * byte of the payload can be put into the
18317 				 * TCP segment.
18318 				 */
18319 				SOCKBUF_UNLOCK(&so->so_snd);
18320 				error = EMSGSIZE;
18321 				sack_rxmit = 0;
18322 				goto out;
18323 			}
18324 			len = tp->t_maxseg - optlen - ipoptlen;
18325 			sendalot = 5;
18326 		}
18327 	} else {
18328 		tso = 0;
18329 		mark = 6;
18330 	}
18331 	KASSERT(len + hdrlen + ipoptlen <= IP_MAXPACKET,
18332 		("%s: len > IP_MAXPACKET", __func__));
18333 #ifdef DIAGNOSTIC
18334 #ifdef INET6
18335 	if (max_linkhdr + hdrlen > MCLBYTES)
18336 #else
18337 		if (max_linkhdr + hdrlen > MHLEN)
18338 #endif
18339 			panic("tcphdr too big");
18340 #endif
18341 
18342 	/*
18343 	 * This KASSERT is here to catch edge cases at a well defined place.
18344 	 * Before, those had triggered (random) panic conditions further
18345 	 * down.
18346 	 */
18347 	KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__));
18348 	if ((len == 0) &&
18349 	    (flags & TH_FIN) &&
18350 	    (sbused(sb))) {
18351 		/*
18352 		 * We have outstanding data, don't send a fin by itself!.
18353 		 */
18354 		goto just_return;
18355 	}
18356 	/*
18357 	 * Grab a header mbuf, attaching a copy of data to be transmitted,
18358 	 * and initialize the header from the template for sends on this
18359 	 * connection.
18360 	 */
18361 	hw_tls = (sb->sb_flags & SB_TLS_IFNET) != 0;
18362 	if (len) {
18363 		uint32_t max_val;
18364 		uint32_t moff;
18365 
18366 		if (rack->r_ctl.rc_pace_max_segs)
18367 			max_val = rack->r_ctl.rc_pace_max_segs;
18368 		else if (rack->rc_user_set_max_segs)
18369 			max_val = rack->rc_user_set_max_segs * segsiz;
18370 		else
18371 			max_val = len;
18372 		/*
18373 		 * We allow a limit on sending with hptsi.
18374 		 */
18375 		if (len > max_val) {
18376 			mark = 7;
18377 			len = max_val;
18378 		}
18379 #ifdef INET6
18380 		if (MHLEN < hdrlen + max_linkhdr)
18381 			m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
18382 		else
18383 #endif
18384 			m = m_gethdr(M_NOWAIT, MT_DATA);
18385 
18386 		if (m == NULL) {
18387 			SOCKBUF_UNLOCK(sb);
18388 			error = ENOBUFS;
18389 			sack_rxmit = 0;
18390 			goto out;
18391 		}
18392 		m->m_data += max_linkhdr;
18393 		m->m_len = hdrlen;
18394 
18395 		/*
18396 		 * Start the m_copy functions from the closest mbuf to the
18397 		 * sb_offset in the socket buffer chain.
18398 		 */
18399 		mb = sbsndptr_noadv(sb, sb_offset, &moff);
18400 		s_mb = mb;
18401 		s_moff = moff;
18402 		if (len <= MHLEN - hdrlen - max_linkhdr && !hw_tls) {
18403 			m_copydata(mb, moff, (int)len,
18404 				   mtod(m, caddr_t)+hdrlen);
18405 			if (SEQ_LT(tp->snd_nxt, tp->snd_max))
18406 				sbsndptr_adv(sb, mb, len);
18407 			m->m_len += len;
18408 		} else {
18409 			struct sockbuf *msb;
18410 
18411 			if (SEQ_LT(tp->snd_nxt, tp->snd_max))
18412 				msb = NULL;
18413 			else
18414 				msb = sb;
18415 			m->m_next = tcp_m_copym(
18416 				mb, moff, &len,
18417 				if_hw_tsomaxsegcount, if_hw_tsomaxsegsize, msb,
18418 				((rsm == NULL) ? hw_tls : 0)
18419 #ifdef NETFLIX_COPY_ARGS
18420 				, &filled_all
18421 #endif
18422 				);
18423 			if (len <= (tp->t_maxseg - optlen)) {
18424 				/*
18425 				 * Must have ran out of mbufs for the copy
18426 				 * shorten it to no longer need tso. Lets
18427 				 * not put on sendalot since we are low on
18428 				 * mbufs.
18429 				 */
18430 				tso = 0;
18431 			}
18432 			if (m->m_next == NULL) {
18433 				SOCKBUF_UNLOCK(sb);
18434 				(void)m_free(m);
18435 				error = ENOBUFS;
18436 				sack_rxmit = 0;
18437 				goto out;
18438 			}
18439 		}
18440 		if (SEQ_LT(tp->snd_nxt, tp->snd_max) || sack_rxmit) {
18441 			if (rsm && (rsm->r_flags & RACK_TLP)) {
18442 				/*
18443 				 * TLP should not count in retran count, but
18444 				 * in its own bin
18445 				 */
18446 				counter_u64_add(rack_tlp_retran, 1);
18447 				counter_u64_add(rack_tlp_retran_bytes, len);
18448 			} else {
18449 				tp->t_sndrexmitpack++;
18450 				KMOD_TCPSTAT_INC(tcps_sndrexmitpack);
18451 				KMOD_TCPSTAT_ADD(tcps_sndrexmitbyte, len);
18452 			}
18453 #ifdef STATS
18454 			stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RETXPB,
18455 						 len);
18456 #endif
18457 		} else {
18458 			KMOD_TCPSTAT_INC(tcps_sndpack);
18459 			KMOD_TCPSTAT_ADD(tcps_sndbyte, len);
18460 #ifdef STATS
18461 			stats_voi_update_abs_u64(tp->t_stats, VOI_TCP_TXPB,
18462 						 len);
18463 #endif
18464 		}
18465 		/*
18466 		 * If we're sending everything we've got, set PUSH. (This
18467 		 * will keep happy those implementations which only give
18468 		 * data to the user when a buffer fills or a PUSH comes in.)
18469 		 */
18470 		if (sb_offset + len == sbused(sb) &&
18471 		    sbused(sb) &&
18472 		    !(flags & TH_SYN)) {
18473 			flags |= TH_PUSH;
18474 			add_flag |= RACK_HAD_PUSH;
18475 		}
18476 
18477 		SOCKBUF_UNLOCK(sb);
18478 	} else {
18479 		SOCKBUF_UNLOCK(sb);
18480 		if (tp->t_flags & TF_ACKNOW)
18481 			KMOD_TCPSTAT_INC(tcps_sndacks);
18482 		else if (flags & (TH_SYN | TH_FIN | TH_RST))
18483 			KMOD_TCPSTAT_INC(tcps_sndctrl);
18484 		else
18485 			KMOD_TCPSTAT_INC(tcps_sndwinup);
18486 
18487 		m = m_gethdr(M_NOWAIT, MT_DATA);
18488 		if (m == NULL) {
18489 			error = ENOBUFS;
18490 			sack_rxmit = 0;
18491 			goto out;
18492 		}
18493 #ifdef INET6
18494 		if (isipv6 && (MHLEN < hdrlen + max_linkhdr) &&
18495 		    MHLEN >= hdrlen) {
18496 			M_ALIGN(m, hdrlen);
18497 		} else
18498 #endif
18499 			m->m_data += max_linkhdr;
18500 		m->m_len = hdrlen;
18501 	}
18502 	SOCKBUF_UNLOCK_ASSERT(sb);
18503 	m->m_pkthdr.rcvif = (struct ifnet *)0;
18504 #ifdef MAC
18505 	mac_inpcb_create_mbuf(inp, m);
18506 #endif
18507 	if ((ipoptlen == 0) && (rack->r_ctl.fsb.tcp_ip_hdr) &&  rack->r_fsb_inited) {
18508 #ifdef INET6
18509 		if (isipv6)
18510 			ip6 = (struct ip6_hdr *)rack->r_ctl.fsb.tcp_ip_hdr;
18511 		else
18512 #endif				/* INET6 */
18513 			ip = (struct ip *)rack->r_ctl.fsb.tcp_ip_hdr;
18514 		th = rack->r_ctl.fsb.th;
18515 		udp = rack->r_ctl.fsb.udp;
18516 		if (udp) {
18517 #ifdef INET6
18518 			if (isipv6)
18519 				ulen = hdrlen + len - sizeof(struct ip6_hdr);
18520 			else
18521 #endif				/* INET6 */
18522 				ulen = hdrlen + len - sizeof(struct ip);
18523 			udp->uh_ulen = htons(ulen);
18524 		}
18525 	} else {
18526 #ifdef INET6
18527 		if (isipv6) {
18528 			ip6 = mtod(m, struct ip6_hdr *);
18529 			if (tp->t_port) {
18530 				udp = (struct udphdr *)((caddr_t)ip6 + sizeof(struct ip6_hdr));
18531 				udp->uh_sport = htons(V_tcp_udp_tunneling_port);
18532 				udp->uh_dport = tp->t_port;
18533 				ulen = hdrlen + len - sizeof(struct ip6_hdr);
18534 				udp->uh_ulen = htons(ulen);
18535 				th = (struct tcphdr *)(udp + 1);
18536 			} else
18537 				th = (struct tcphdr *)(ip6 + 1);
18538 			tcpip_fillheaders(inp, tp->t_port, ip6, th);
18539 		} else
18540 #endif				/* INET6 */
18541 		{
18542 			ip = mtod(m, struct ip *);
18543 #ifdef TCPDEBUG
18544 			ipov = (struct ipovly *)ip;
18545 #endif
18546 			if (tp->t_port) {
18547 				udp = (struct udphdr *)((caddr_t)ip + sizeof(struct ip));
18548 				udp->uh_sport = htons(V_tcp_udp_tunneling_port);
18549 				udp->uh_dport = tp->t_port;
18550 				ulen = hdrlen + len - sizeof(struct ip);
18551 				udp->uh_ulen = htons(ulen);
18552 				th = (struct tcphdr *)(udp + 1);
18553 			} else
18554 				th = (struct tcphdr *)(ip + 1);
18555 			tcpip_fillheaders(inp, tp->t_port, ip, th);
18556 		}
18557 	}
18558 	/*
18559 	 * Fill in fields, remembering maximum advertised window for use in
18560 	 * delaying messages about window sizes. If resending a FIN, be sure
18561 	 * not to use a new sequence number.
18562 	 */
18563 	if (flags & TH_FIN && tp->t_flags & TF_SENTFIN &&
18564 	    tp->snd_nxt == tp->snd_max)
18565 		tp->snd_nxt--;
18566 	/*
18567 	 * If we are starting a connection, send ECN setup SYN packet. If we
18568 	 * are on a retransmit, we may resend those bits a number of times
18569 	 * as per RFC 3168.
18570 	 */
18571 	if (tp->t_state == TCPS_SYN_SENT && V_tcp_do_ecn == 1) {
18572 		if (tp->t_rxtshift >= 1) {
18573 			if (tp->t_rxtshift <= V_tcp_ecn_maxretries)
18574 				flags |= TH_ECE | TH_CWR;
18575 		} else
18576 			flags |= TH_ECE | TH_CWR;
18577 	}
18578 	/* Handle parallel SYN for ECN */
18579 	if ((tp->t_state == TCPS_SYN_RECEIVED) &&
18580 	    (tp->t_flags2 & TF2_ECN_SND_ECE)) {
18581 		flags |= TH_ECE;
18582 		tp->t_flags2 &= ~TF2_ECN_SND_ECE;
18583 	}
18584 	if (TCPS_HAVEESTABLISHED(tp->t_state) &&
18585 	    (tp->t_flags2 & TF2_ECN_PERMIT)) {
18586 		/*
18587 		 * If the peer has ECN, mark data packets with ECN capable
18588 		 * transmission (ECT). Ignore pure ack packets,
18589 		 * retransmissions.
18590 		 */
18591 		if (len > 0 && SEQ_GEQ(tp->snd_nxt, tp->snd_max) &&
18592 		    (sack_rxmit == 0)) {
18593 #ifdef INET6
18594 			if (isipv6)
18595 				ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20);
18596 			else
18597 #endif
18598 				ip->ip_tos |= IPTOS_ECN_ECT0;
18599 			KMOD_TCPSTAT_INC(tcps_ecn_ect0);
18600 			/*
18601 			 * Reply with proper ECN notifications.
18602 			 * Only set CWR on new data segments.
18603 			 */
18604 			if (tp->t_flags2 & TF2_ECN_SND_CWR) {
18605 				flags |= TH_CWR;
18606 				tp->t_flags2 &= ~TF2_ECN_SND_CWR;
18607 			}
18608 		}
18609 		if (tp->t_flags2 & TF2_ECN_SND_ECE)
18610 			flags |= TH_ECE;
18611 	}
18612 	/*
18613 	 * If we are doing retransmissions, then snd_nxt will not reflect
18614 	 * the first unsent octet.  For ACK only packets, we do not want the
18615 	 * sequence number of the retransmitted packet, we want the sequence
18616 	 * number of the next unsent octet.  So, if there is no data (and no
18617 	 * SYN or FIN), use snd_max instead of snd_nxt when filling in
18618 	 * ti_seq.  But if we are in persist state, snd_max might reflect
18619 	 * one byte beyond the right edge of the window, so use snd_nxt in
18620 	 * that case, since we know we aren't doing a retransmission.
18621 	 * (retransmit and persist are mutually exclusive...)
18622 	 */
18623 	if (sack_rxmit == 0) {
18624 		if (len || (flags & (TH_SYN | TH_FIN))) {
18625 			th->th_seq = htonl(tp->snd_nxt);
18626 			rack_seq = tp->snd_nxt;
18627 		} else {
18628 			th->th_seq = htonl(tp->snd_max);
18629 			rack_seq = tp->snd_max;
18630 		}
18631 	} else {
18632 		th->th_seq = htonl(rsm->r_start);
18633 		rack_seq = rsm->r_start;
18634 	}
18635 	th->th_ack = htonl(tp->rcv_nxt);
18636 	th->th_flags = flags;
18637 	/*
18638 	 * Calculate receive window.  Don't shrink window, but avoid silly
18639 	 * window syndrome.
18640 	 * If a RST segment is sent, advertise a window of zero.
18641 	 */
18642 	if (flags & TH_RST) {
18643 		recwin = 0;
18644 	} else {
18645 		if (recwin < (long)(so->so_rcv.sb_hiwat / 4) &&
18646 		    recwin < (long)segsiz) {
18647 			recwin = 0;
18648 		}
18649 		if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt) &&
18650 		    recwin < (long)(tp->rcv_adv - tp->rcv_nxt))
18651 			recwin = (long)(tp->rcv_adv - tp->rcv_nxt);
18652 	}
18653 
18654 	/*
18655 	 * According to RFC1323 the window field in a SYN (i.e., a <SYN> or
18656 	 * <SYN,ACK>) segment itself is never scaled.  The <SYN,ACK> case is
18657 	 * handled in syncache.
18658 	 */
18659 	if (flags & TH_SYN)
18660 		th->th_win = htons((u_short)
18661 				   (min(sbspace(&so->so_rcv), TCP_MAXWIN)));
18662 	else {
18663 		/* Avoid shrinking window with window scaling. */
18664 		recwin = roundup2(recwin, 1 << tp->rcv_scale);
18665 		th->th_win = htons((u_short)(recwin >> tp->rcv_scale));
18666 	}
18667 	/*
18668 	 * Adjust the RXWIN0SENT flag - indicate that we have advertised a 0
18669 	 * window.  This may cause the remote transmitter to stall.  This
18670 	 * flag tells soreceive() to disable delayed acknowledgements when
18671 	 * draining the buffer.  This can occur if the receiver is
18672 	 * attempting to read more data than can be buffered prior to
18673 	 * transmitting on the connection.
18674 	 */
18675 	if (th->th_win == 0) {
18676 		tp->t_sndzerowin++;
18677 		tp->t_flags |= TF_RXWIN0SENT;
18678 	} else
18679 		tp->t_flags &= ~TF_RXWIN0SENT;
18680 	tp->snd_up = tp->snd_una;	/* drag it along, its deprecated */
18681 	/* Now are we using fsb?, if so copy the template data to the mbuf */
18682 	if ((ipoptlen == 0) && (rack->r_ctl.fsb.tcp_ip_hdr) && rack->r_fsb_inited) {
18683 		uint8_t *cpto;
18684 
18685 		cpto = mtod(m, uint8_t *);
18686 		memcpy(cpto, rack->r_ctl.fsb.tcp_ip_hdr, rack->r_ctl.fsb.tcp_ip_hdr_len);
18687 		/*
18688 		 * We have just copied in:
18689 		 * IP/IP6
18690 		 * <optional udphdr>
18691 		 * tcphdr (no options)
18692 		 *
18693 		 * We need to grab the correct pointers into the mbuf
18694 		 * for both the tcp header, and possibly the udp header (if tunneling).
18695 		 * We do this by using the offset in the copy buffer and adding it
18696 		 * to the mbuf base pointer (cpto).
18697 		 */
18698 #ifdef INET6
18699 		if (isipv6)
18700 			ip6 = mtod(m, struct ip6_hdr *);
18701 		else
18702 #endif				/* INET6 */
18703 			ip = mtod(m, struct ip *);
18704 		th = (struct tcphdr *)(cpto + ((uint8_t *)rack->r_ctl.fsb.th - rack->r_ctl.fsb.tcp_ip_hdr));
18705 		/* If we have a udp header lets set it into the mbuf as well */
18706 		if (udp)
18707 			udp = (struct udphdr *)(cpto + ((uint8_t *)rack->r_ctl.fsb.udp - rack->r_ctl.fsb.tcp_ip_hdr));
18708 	}
18709 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
18710 	if (to.to_flags & TOF_SIGNATURE) {
18711 		/*
18712 		 * Calculate MD5 signature and put it into the place
18713 		 * determined before.
18714 		 * NOTE: since TCP options buffer doesn't point into
18715 		 * mbuf's data, calculate offset and use it.
18716 		 */
18717 		if (!TCPMD5_ENABLED() || TCPMD5_OUTPUT(m, th,
18718 						       (u_char *)(th + 1) + (to.to_signature - opt)) != 0) {
18719 			/*
18720 			 * Do not send segment if the calculation of MD5
18721 			 * digest has failed.
18722 			 */
18723 			goto out;
18724 		}
18725 	}
18726 #endif
18727 	if (optlen) {
18728 		bcopy(opt, th + 1, optlen);
18729 		th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
18730 	}
18731 	/*
18732 	 * Put TCP length in extended header, and then checksum extended
18733 	 * header and data.
18734 	 */
18735 	m->m_pkthdr.len = hdrlen + len;	/* in6_cksum() need this */
18736 #ifdef INET6
18737 	if (isipv6) {
18738 		/*
18739 		 * ip6_plen is not need to be filled now, and will be filled
18740 		 * in ip6_output.
18741 		 */
18742 		if (tp->t_port) {
18743 			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
18744 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
18745 			udp->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0);
18746 			th->th_sum = htons(0);
18747 			UDPSTAT_INC(udps_opackets);
18748 		} else {
18749 			m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
18750 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
18751 			th->th_sum = in6_cksum_pseudo(ip6,
18752 						      sizeof(struct tcphdr) + optlen + len, IPPROTO_TCP,
18753 						      0);
18754 		}
18755 	}
18756 #endif
18757 #if defined(INET6) && defined(INET)
18758 	else
18759 #endif
18760 #ifdef INET
18761 	{
18762 		if (tp->t_port) {
18763 			m->m_pkthdr.csum_flags = CSUM_UDP;
18764 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
18765 			udp->uh_sum = in_pseudo(ip->ip_src.s_addr,
18766 						ip->ip_dst.s_addr, htons(ulen + IPPROTO_UDP));
18767 			th->th_sum = htons(0);
18768 			UDPSTAT_INC(udps_opackets);
18769 		} else {
18770 			m->m_pkthdr.csum_flags = CSUM_TCP;
18771 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
18772 			th->th_sum = in_pseudo(ip->ip_src.s_addr,
18773 					       ip->ip_dst.s_addr, htons(sizeof(struct tcphdr) +
18774 									IPPROTO_TCP + len + optlen));
18775 		}
18776 		/* IP version must be set here for ipv4/ipv6 checking later */
18777 		KASSERT(ip->ip_v == IPVERSION,
18778 			("%s: IP version incorrect: %d", __func__, ip->ip_v));
18779 	}
18780 #endif
18781 	/*
18782 	 * Enable TSO and specify the size of the segments. The TCP pseudo
18783 	 * header checksum is always provided. XXX: Fixme: This is currently
18784 	 * not the case for IPv6.
18785 	 */
18786 	if (tso) {
18787 		KASSERT(len > tp->t_maxseg - optlen,
18788 			("%s: len <= tso_segsz", __func__));
18789 		m->m_pkthdr.csum_flags |= CSUM_TSO;
18790 		m->m_pkthdr.tso_segsz = tp->t_maxseg - optlen;
18791 	}
18792 	KASSERT(len + hdrlen == m_length(m, NULL),
18793 		("%s: mbuf chain different than expected: %d + %u != %u",
18794 		 __func__, len, hdrlen, m_length(m, NULL)));
18795 
18796 #ifdef TCP_HHOOK
18797 	/* Run HHOOK_TCP_ESTABLISHED_OUT helper hooks. */
18798 	hhook_run_tcp_est_out(tp, th, &to, len, tso);
18799 #endif
18800 	/* We're getting ready to send; log now. */
18801 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
18802 		union tcp_log_stackspecific log;
18803 
18804 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
18805 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
18806 		log.u_bbr.ininput = rack->rc_inp->inp_in_dropq;
18807 		if (rack->rack_no_prr)
18808 			log.u_bbr.flex1 = 0;
18809 		else
18810 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
18811 		log.u_bbr.flex2 = rack->r_ctl.rc_pace_min_segs;
18812 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_max_segs;
18813 		log.u_bbr.flex4 = orig_len;
18814 		if (filled_all)
18815 			log.u_bbr.flex5 = 0x80000000;
18816 		else
18817 			log.u_bbr.flex5 = 0;
18818 		/* Save off the early/late values */
18819 		log.u_bbr.flex6 = rack->r_ctl.rc_agg_early;
18820 		log.u_bbr.applimited = rack->r_ctl.rc_agg_delayed;
18821 		log.u_bbr.bw_inuse = rack_get_bw(rack);
18822 		if (rsm || sack_rxmit) {
18823 			if (doing_tlp)
18824 				log.u_bbr.flex8 = 2;
18825 			else
18826 				log.u_bbr.flex8 = 1;
18827 		} else {
18828 			if (doing_tlp)
18829 				log.u_bbr.flex8 = 3;
18830 			else
18831 				log.u_bbr.flex8 = 0;
18832 		}
18833 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, rsm);
18834 		log.u_bbr.flex7 = mark;
18835 		log.u_bbr.flex7 <<= 8;
18836 		log.u_bbr.flex7 |= pass;
18837 		log.u_bbr.pkts_out = tp->t_maxseg;
18838 		log.u_bbr.timeStamp = cts;
18839 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
18840 		log.u_bbr.lt_epoch = cwnd_to_use;
18841 		log.u_bbr.delivered = sendalot;
18842 		lgb = tcp_log_event_(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_OUT, ERRNO_UNK,
18843 				     len, &log, false, NULL, NULL, 0, &tv);
18844 	} else
18845 		lgb = NULL;
18846 
18847 	/*
18848 	 * Fill in IP length and desired time to live and send to IP level.
18849 	 * There should be a better way to handle ttl and tos; we could keep
18850 	 * them in the template, but need a way to checksum without them.
18851 	 */
18852 	/*
18853 	 * m->m_pkthdr.len should have been set before cksum calcuration,
18854 	 * because in6_cksum() need it.
18855 	 */
18856 #ifdef INET6
18857 	if (isipv6) {
18858 		/*
18859 		 * we separately set hoplimit for every segment, since the
18860 		 * user might want to change the value via setsockopt. Also,
18861 		 * desired default hop limit might be changed via Neighbor
18862 		 * Discovery.
18863 		 */
18864 		rack->r_ctl.fsb.hoplimit = ip6->ip6_hlim = in6_selecthlim(inp, NULL);
18865 
18866 		/*
18867 		 * Set the packet size here for the benefit of DTrace
18868 		 * probes. ip6_output() will set it properly; it's supposed
18869 		 * to include the option header lengths as well.
18870 		 */
18871 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
18872 
18873 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss)
18874 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
18875 		else
18876 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
18877 
18878 		if (tp->t_state == TCPS_SYN_SENT)
18879 			TCP_PROBE5(connect__request, NULL, tp, ip6, tp, th);
18880 
18881 		TCP_PROBE5(send, NULL, tp, ip6, tp, th);
18882 		/* TODO: IPv6 IP6TOS_ECT bit on */
18883 		error = ip6_output(m,
18884 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
18885 				   inp->in6p_outputopts,
18886 #else
18887 				   NULL,
18888 #endif
18889 				   &inp->inp_route6,
18890 				   ((rsm || sack_rxmit) ? IP_NO_SND_TAG_RL : 0),
18891 				   NULL, NULL, inp);
18892 
18893 		if (error == EMSGSIZE && inp->inp_route6.ro_nh != NULL)
18894 			mtu = inp->inp_route6.ro_nh->nh_mtu;
18895 	}
18896 #endif				/* INET6 */
18897 #if defined(INET) && defined(INET6)
18898 	else
18899 #endif
18900 #ifdef INET
18901 	{
18902 		ip->ip_len = htons(m->m_pkthdr.len);
18903 #ifdef INET6
18904 		if (inp->inp_vflag & INP_IPV6PROTO)
18905 			ip->ip_ttl = in6_selecthlim(inp, NULL);
18906 #endif				/* INET6 */
18907 		rack->r_ctl.fsb.hoplimit = ip->ip_ttl;
18908 		/*
18909 		 * If we do path MTU discovery, then we set DF on every
18910 		 * packet. This might not be the best thing to do according
18911 		 * to RFC3390 Section 2. However the tcp hostcache migitates
18912 		 * the problem so it affects only the first tcp connection
18913 		 * with a host.
18914 		 *
18915 		 * NB: Don't set DF on small MTU/MSS to have a safe
18916 		 * fallback.
18917 		 */
18918 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) {
18919 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
18920 			if (tp->t_port == 0 || len < V_tcp_minmss) {
18921 				ip->ip_off |= htons(IP_DF);
18922 			}
18923 		} else {
18924 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
18925 		}
18926 
18927 		if (tp->t_state == TCPS_SYN_SENT)
18928 			TCP_PROBE5(connect__request, NULL, tp, ip, tp, th);
18929 
18930 		TCP_PROBE5(send, NULL, tp, ip, tp, th);
18931 
18932 		error = ip_output(m,
18933 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
18934 				  inp->inp_options,
18935 #else
18936 				  NULL,
18937 #endif
18938 				  &inp->inp_route,
18939 				  ((rsm || sack_rxmit) ? IP_NO_SND_TAG_RL : 0), 0,
18940 				  inp);
18941 		if (error == EMSGSIZE && inp->inp_route.ro_nh != NULL)
18942 			mtu = inp->inp_route.ro_nh->nh_mtu;
18943 	}
18944 #endif				/* INET */
18945 
18946 out:
18947 	if (lgb) {
18948 		lgb->tlb_errno = error;
18949 		lgb = NULL;
18950 	}
18951 	/*
18952 	 * In transmit state, time the transmission and arrange for the
18953 	 * retransmit.  In persist state, just set snd_max.
18954 	 */
18955 	if (error == 0) {
18956 		tcp_account_for_send(tp, len, (rsm != NULL), doing_tlp, hw_tls);
18957 		if (rsm && doing_tlp) {
18958 			rack->rc_last_sent_tlp_past_cumack = 0;
18959 			rack->rc_last_sent_tlp_seq_valid = 1;
18960 			rack->r_ctl.last_sent_tlp_seq = rsm->r_start;
18961 			rack->r_ctl.last_sent_tlp_len = rsm->r_end - rsm->r_start;
18962 		}
18963 		rack->forced_ack = 0;	/* If we send something zap the FA flag */
18964 		if (rsm && (doing_tlp == 0)) {
18965 			/* Set we retransmitted */
18966 			rack->rc_gp_saw_rec = 1;
18967 		} else {
18968 			if (cwnd_to_use > tp->snd_ssthresh) {
18969 				/* Set we sent in CA */
18970 				rack->rc_gp_saw_ca = 1;
18971 			} else {
18972 				/* Set we sent in SS */
18973 				rack->rc_gp_saw_ss = 1;
18974 			}
18975 		}
18976 		if (TCPS_HAVEESTABLISHED(tp->t_state) &&
18977 		    (tp->t_flags & TF_SACK_PERMIT) &&
18978 		    tp->rcv_numsacks > 0)
18979 			tcp_clean_dsack_blocks(tp);
18980 		tot_len_this_send += len;
18981 		if (len == 0)
18982 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_SNDACK], 1);
18983 		else if (len == 1) {
18984 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_PERSIST], 1);
18985 		} else if (len > 1) {
18986 			int idx;
18987 
18988 			idx = (len / segsiz) + 3;
18989 			if (idx >= TCP_MSS_ACCT_ATIMER)
18990 				counter_u64_add(rack_out_size[(TCP_MSS_ACCT_ATIMER-1)], 1);
18991 			else
18992 				counter_u64_add(rack_out_size[idx], 1);
18993 		}
18994 	}
18995 	if ((rack->rack_no_prr == 0) &&
18996 	    sub_from_prr &&
18997 	    (error == 0)) {
18998 		if (rack->r_ctl.rc_prr_sndcnt >= len)
18999 			rack->r_ctl.rc_prr_sndcnt -= len;
19000 		else
19001 			rack->r_ctl.rc_prr_sndcnt = 0;
19002 	}
19003 	sub_from_prr = 0;
19004 	if (doing_tlp) {
19005 		/* Make sure the TLP is added */
19006 		add_flag |= RACK_TLP;
19007 	} else if (rsm) {
19008 		/* If its a resend without TLP then it must not have the flag */
19009 		rsm->r_flags &= ~RACK_TLP;
19010 	}
19011 	rack_log_output(tp, &to, len, rack_seq, (uint8_t) flags, error,
19012 			rack_to_usec_ts(&tv),
19013 			rsm, add_flag, s_mb, s_moff, hw_tls);
19014 
19015 
19016 	if ((error == 0) &&
19017 	    (len > 0) &&
19018 	    (tp->snd_una == tp->snd_max))
19019 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
19020 	{
19021 		tcp_seq startseq = tp->snd_nxt;
19022 
19023 		/* Track our lost count */
19024 		if (rsm && (doing_tlp == 0))
19025 			rack->r_ctl.rc_loss_count += rsm->r_end - rsm->r_start;
19026 		/*
19027 		 * Advance snd_nxt over sequence space of this segment.
19028 		 */
19029 		if (error)
19030 			/* We don't log or do anything with errors */
19031 			goto nomore;
19032 		if (doing_tlp == 0) {
19033 			if (rsm == NULL) {
19034 				/*
19035 				 * Not a retransmission of some
19036 				 * sort, new data is going out so
19037 				 * clear our TLP count and flag.
19038 				 */
19039 				rack->rc_tlp_in_progress = 0;
19040 				rack->r_ctl.rc_tlp_cnt_out = 0;
19041 			}
19042 		} else {
19043 			/*
19044 			 * We have just sent a TLP, mark that it is true
19045 			 * and make sure our in progress is set so we
19046 			 * continue to check the count.
19047 			 */
19048 			rack->rc_tlp_in_progress = 1;
19049 			rack->r_ctl.rc_tlp_cnt_out++;
19050 		}
19051 		if (flags & (TH_SYN | TH_FIN)) {
19052 			if (flags & TH_SYN)
19053 				tp->snd_nxt++;
19054 			if (flags & TH_FIN) {
19055 				tp->snd_nxt++;
19056 				tp->t_flags |= TF_SENTFIN;
19057 			}
19058 		}
19059 		/* In the ENOBUFS case we do *not* update snd_max */
19060 		if (sack_rxmit)
19061 			goto nomore;
19062 
19063 		tp->snd_nxt += len;
19064 		if (SEQ_GT(tp->snd_nxt, tp->snd_max)) {
19065 			if (tp->snd_una == tp->snd_max) {
19066 				/*
19067 				 * Update the time we just added data since
19068 				 * none was outstanding.
19069 				 */
19070 				rack_log_progress_event(rack, tp, ticks, PROGRESS_START, __LINE__);
19071 				tp->t_acktime = ticks;
19072 			}
19073 			tp->snd_max = tp->snd_nxt;
19074 			/*
19075 			 * Time this transmission if not a retransmission and
19076 			 * not currently timing anything.
19077 			 * This is only relevant in case of switching back to
19078 			 * the base stack.
19079 			 */
19080 			if (tp->t_rtttime == 0) {
19081 				tp->t_rtttime = ticks;
19082 				tp->t_rtseq = startseq;
19083 				KMOD_TCPSTAT_INC(tcps_segstimed);
19084 			}
19085 			if (len &&
19086 			    ((tp->t_flags & TF_GPUTINPROG) == 0))
19087 				rack_start_gp_measurement(tp, rack, startseq, sb_offset);
19088 		}
19089 		/*
19090 		 * If we are doing FO we need to update the mbuf position and subtract
19091 		 * this happens when the peer sends us duplicate information and
19092 		 * we thus want to send a DSACK.
19093 		 *
19094 		 * XXXRRS: This brings to mind a ?, when we send a DSACK block is TSO
19095 		 * turned off? If not then we are going to echo multiple DSACK blocks
19096 		 * out (with the TSO), which we should not be doing.
19097 		 */
19098 		if (rack->r_fast_output && len) {
19099 			if (rack->r_ctl.fsb.left_to_send > len)
19100 				rack->r_ctl.fsb.left_to_send -= len;
19101 			else
19102 				rack->r_ctl.fsb.left_to_send = 0;
19103 			if (rack->r_ctl.fsb.left_to_send < segsiz)
19104 				rack->r_fast_output = 0;
19105 			if (rack->r_fast_output) {
19106 				rack->r_ctl.fsb.m = sbsndmbuf(sb, (tp->snd_max - tp->snd_una), &rack->r_ctl.fsb.off);
19107 				rack->r_ctl.fsb.o_m_len = rack->r_ctl.fsb.m->m_len;
19108 			}
19109 		}
19110 	}
19111 nomore:
19112 	if (error) {
19113 		rack->r_ctl.rc_agg_delayed = 0;
19114 		rack->r_early = 0;
19115 		rack->r_late = 0;
19116 		rack->r_ctl.rc_agg_early = 0;
19117 		SOCKBUF_UNLOCK_ASSERT(sb);	/* Check gotos. */
19118 		/*
19119 		 * Failures do not advance the seq counter above. For the
19120 		 * case of ENOBUFS we will fall out and retry in 1ms with
19121 		 * the hpts. Everything else will just have to retransmit
19122 		 * with the timer.
19123 		 *
19124 		 * In any case, we do not want to loop around for another
19125 		 * send without a good reason.
19126 		 */
19127 		sendalot = 0;
19128 		switch (error) {
19129 		case EPERM:
19130 			tp->t_softerror = error;
19131 #ifdef TCP_ACCOUNTING
19132 			crtsc = get_cyclecount();
19133 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19134 				tp->tcp_cnt_counters[SND_OUT_FAIL]++;
19135 			}
19136 			counter_u64_add(tcp_cnt_counters[SND_OUT_FAIL], 1);
19137 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19138 				tp->tcp_proc_time[SND_OUT_FAIL] += (crtsc - ts_val);
19139 			}
19140 			counter_u64_add(tcp_proc_time[SND_OUT_FAIL], (crtsc - ts_val));
19141 			sched_unpin();
19142 #endif
19143 			return (error);
19144 		case ENOBUFS:
19145 			/*
19146 			 * Pace us right away to retry in a some
19147 			 * time
19148 			 */
19149 			slot = ((1 + rack->rc_enobuf) * HPTS_USEC_IN_MSEC);
19150 			if (rack->rc_enobuf < 0x7f)
19151 				rack->rc_enobuf++;
19152 			if (slot < (10 * HPTS_USEC_IN_MSEC))
19153 				slot = 10 * HPTS_USEC_IN_MSEC;
19154 			if (rack->r_ctl.crte != NULL) {
19155 				counter_u64_add(rack_saw_enobuf_hw, 1);
19156 				tcp_rl_log_enobuf(rack->r_ctl.crte);
19157 			}
19158 			counter_u64_add(rack_saw_enobuf, 1);
19159 			goto enobufs;
19160 		case EMSGSIZE:
19161 			/*
19162 			 * For some reason the interface we used initially
19163 			 * to send segments changed to another or lowered
19164 			 * its MTU. If TSO was active we either got an
19165 			 * interface without TSO capabilits or TSO was
19166 			 * turned off. If we obtained mtu from ip_output()
19167 			 * then update it and try again.
19168 			 */
19169 			if (tso)
19170 				tp->t_flags &= ~TF_TSO;
19171 			if (mtu != 0) {
19172 				tcp_mss_update(tp, -1, mtu, NULL, NULL);
19173 				goto again;
19174 			}
19175 			slot = 10 * HPTS_USEC_IN_MSEC;
19176 			rack_start_hpts_timer(rack, tp, cts, slot, 0, 0);
19177 #ifdef TCP_ACCOUNTING
19178 			crtsc = get_cyclecount();
19179 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19180 				tp->tcp_cnt_counters[SND_OUT_FAIL]++;
19181 			}
19182 			counter_u64_add(tcp_cnt_counters[SND_OUT_FAIL], 1);
19183 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19184 				tp->tcp_proc_time[SND_OUT_FAIL] += (crtsc - ts_val);
19185 			}
19186 			counter_u64_add(tcp_proc_time[SND_OUT_FAIL], (crtsc - ts_val));
19187 			sched_unpin();
19188 #endif
19189 			return (error);
19190 		case ENETUNREACH:
19191 			counter_u64_add(rack_saw_enetunreach, 1);
19192 		case EHOSTDOWN:
19193 		case EHOSTUNREACH:
19194 		case ENETDOWN:
19195 			if (TCPS_HAVERCVDSYN(tp->t_state)) {
19196 				tp->t_softerror = error;
19197 			}
19198 			/* FALLTHROUGH */
19199 		default:
19200 			slot = 10 * HPTS_USEC_IN_MSEC;
19201 			rack_start_hpts_timer(rack, tp, cts, slot, 0, 0);
19202 #ifdef TCP_ACCOUNTING
19203 			crtsc = get_cyclecount();
19204 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19205 				tp->tcp_cnt_counters[SND_OUT_FAIL]++;
19206 			}
19207 			counter_u64_add(tcp_cnt_counters[SND_OUT_FAIL], 1);
19208 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19209 				tp->tcp_proc_time[SND_OUT_FAIL] += (crtsc - ts_val);
19210 			}
19211 			counter_u64_add(tcp_proc_time[SND_OUT_FAIL], (crtsc - ts_val));
19212 			sched_unpin();
19213 #endif
19214 			return (error);
19215 		}
19216 	} else {
19217 		rack->rc_enobuf = 0;
19218 		if (IN_FASTRECOVERY(tp->t_flags) && rsm)
19219 			rack->r_ctl.retran_during_recovery += len;
19220 	}
19221 	KMOD_TCPSTAT_INC(tcps_sndtotal);
19222 
19223 	/*
19224 	 * Data sent (as far as we can tell). If this advertises a larger
19225 	 * window than any other segment, then remember the size of the
19226 	 * advertised window. Any pending ACK has now been sent.
19227 	 */
19228 	if (recwin > 0 && SEQ_GT(tp->rcv_nxt + recwin, tp->rcv_adv))
19229 		tp->rcv_adv = tp->rcv_nxt + recwin;
19230 
19231 	tp->last_ack_sent = tp->rcv_nxt;
19232 	tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
19233 enobufs:
19234 	if (sendalot) {
19235 		/* Do we need to turn off sendalot? */
19236 		if (rack->r_ctl.rc_pace_max_segs &&
19237 		    (tot_len_this_send >= rack->r_ctl.rc_pace_max_segs)) {
19238 			/* We hit our max. */
19239 			sendalot = 0;
19240 		} else if ((rack->rc_user_set_max_segs) &&
19241 			   (tot_len_this_send >= (rack->rc_user_set_max_segs * segsiz))) {
19242 			/* We hit the user defined max */
19243 			sendalot = 0;
19244 		}
19245 	}
19246 	if ((error == 0) && (flags & TH_FIN))
19247 		tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_FIN);
19248 	if (flags & TH_RST) {
19249 		/*
19250 		 * We don't send again after sending a RST.
19251 		 */
19252 		slot = 0;
19253 		sendalot = 0;
19254 		if (error == 0)
19255 			tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
19256 	} else if ((slot == 0) && (sendalot == 0) && tot_len_this_send) {
19257 		/*
19258 		 * Get our pacing rate, if an error
19259 		 * occurred in sending (ENOBUF) we would
19260 		 * hit the else if with slot preset. Other
19261 		 * errors return.
19262 		 */
19263 		slot = rack_get_pacing_delay(rack, tp, tot_len_this_send, rsm, segsiz);
19264 	}
19265 	if (rsm &&
19266 	    (rsm->r_flags & RACK_HAS_SYN) == 0 &&
19267 	    rack->use_rack_rr) {
19268 		/* Its a retransmit and we use the rack cheat? */
19269 		if ((slot == 0) ||
19270 		    (rack->rc_always_pace == 0) ||
19271 		    (rack->r_rr_config == 1)) {
19272 			/*
19273 			 * We have no pacing set or we
19274 			 * are using old-style rack or
19275 			 * we are overriden to use the old 1ms pacing.
19276 			 */
19277 			slot = rack->r_ctl.rc_min_to;
19278 		}
19279 	}
19280 	/* We have sent clear the flag */
19281 	rack->r_ent_rec_ns = 0;
19282 	if (rack->r_must_retran) {
19283 		if (rsm) {
19284 			rack->r_ctl.rc_out_at_rto -= (rsm->r_end - rsm->r_start);
19285 			if (SEQ_GEQ(rsm->r_end, rack->r_ctl.rc_snd_max_at_rto)) {
19286 				/*
19287 				 * We have retransmitted all.
19288 				 */
19289 				rack->r_must_retran = 0;
19290 				rack->r_ctl.rc_out_at_rto = 0;
19291 			}
19292 		} else if (SEQ_GEQ(tp->snd_max, rack->r_ctl.rc_snd_max_at_rto)) {
19293 			/*
19294 			 * Sending new data will also kill
19295 			 * the loop.
19296 			 */
19297 			rack->r_must_retran = 0;
19298 			rack->r_ctl.rc_out_at_rto = 0;
19299 		}
19300 	}
19301 	rack->r_ctl.fsb.recwin = recwin;
19302 	if ((tp->t_flags & (TF_WASCRECOVERY|TF_WASFRECOVERY)) &&
19303 	    SEQ_GT(tp->snd_max, rack->r_ctl.rc_snd_max_at_rto)) {
19304 		/*
19305 		 * We hit an RTO and now have past snd_max at the RTO
19306 		 * clear all the WAS flags.
19307 		 */
19308 		tp->t_flags &= ~(TF_WASCRECOVERY|TF_WASFRECOVERY);
19309 	}
19310 	if (slot) {
19311 		/* set the rack tcb into the slot N */
19312 		counter_u64_add(rack_paced_segments, 1);
19313 		if ((error == 0) &&
19314 		    rack_use_rfo &&
19315 		    ((flags & (TH_SYN|TH_FIN)) == 0) &&
19316 		    (rsm == NULL) &&
19317 		    (tp->snd_nxt == tp->snd_max) &&
19318 		    (ipoptlen == 0) &&
19319 		    (tp->rcv_numsacks == 0) &&
19320 		    rack->r_fsb_inited &&
19321 		    TCPS_HAVEESTABLISHED(tp->t_state) &&
19322 		    (rack->r_must_retran == 0) &&
19323 		    ((tp->t_flags & TF_NEEDFIN) == 0) &&
19324 		    (len > 0) && (orig_len > 0) &&
19325 		    (orig_len > len) &&
19326 		    ((orig_len - len) >= segsiz) &&
19327 		    ((optlen == 0) ||
19328 		     ((optlen == TCPOLEN_TSTAMP_APPA) && (to.to_flags & TOF_TS)))) {
19329 			/* We can send at least one more MSS using our fsb */
19330 
19331 			rack->r_fast_output = 1;
19332 			rack->r_ctl.fsb.m = sbsndmbuf(sb, (tp->snd_max - tp->snd_una), &rack->r_ctl.fsb.off);
19333 			rack->r_ctl.fsb.o_m_len = rack->r_ctl.fsb.m->m_len;
19334 			rack->r_ctl.fsb.tcp_flags = flags;
19335 			rack->r_ctl.fsb.left_to_send = orig_len - len;
19336 			if (hw_tls)
19337 				rack->r_ctl.fsb.hw_tls = 1;
19338 			else
19339 				rack->r_ctl.fsb.hw_tls = 0;
19340 			KASSERT((rack->r_ctl.fsb.left_to_send <= (sbavail(sb) - (tp->snd_max - tp->snd_una))),
19341 				("rack:%p left_to_send:%u sbavail:%u out:%u",
19342 				 rack, rack->r_ctl.fsb.left_to_send, sbavail(sb),
19343 				 (tp->snd_max - tp->snd_una)));
19344 			if (rack->r_ctl.fsb.left_to_send < segsiz)
19345 				rack->r_fast_output = 0;
19346 			else {
19347 				if (rack->r_ctl.fsb.left_to_send == (sbavail(sb) - (tp->snd_max - tp->snd_una)))
19348 					rack->r_ctl.fsb.rfo_apply_push = 1;
19349 				else
19350 					rack->r_ctl.fsb.rfo_apply_push = 0;
19351 			}
19352 		} else
19353 			rack->r_fast_output = 0;
19354 		rack_log_fsb(rack, tp, so, flags,
19355 			     ipoptlen, orig_len, len, error,
19356 			     (rsm == NULL), optlen, __LINE__, 2);
19357 	} else if (sendalot) {
19358 		int ret;
19359 
19360 		if (len)
19361 			counter_u64_add(rack_unpaced_segments, 1);
19362 		sack_rxmit = 0;
19363 		if ((error == 0) &&
19364 		    rack_use_rfo &&
19365 		    ((flags & (TH_SYN|TH_FIN)) == 0) &&
19366 		    (rsm == NULL) &&
19367 		    (ipoptlen == 0) &&
19368 		    (tp->rcv_numsacks == 0) &&
19369 		    (tp->snd_nxt == tp->snd_max) &&
19370 		    (rack->r_must_retran == 0) &&
19371 		    rack->r_fsb_inited &&
19372 		    TCPS_HAVEESTABLISHED(tp->t_state) &&
19373 		    ((tp->t_flags & TF_NEEDFIN) == 0) &&
19374 		    (len > 0) && (orig_len > 0) &&
19375 		    (orig_len > len) &&
19376 		    ((orig_len - len) >= segsiz) &&
19377 		    ((optlen == 0) ||
19378 		     ((optlen == TCPOLEN_TSTAMP_APPA) && (to.to_flags & TOF_TS)))) {
19379 			/* we can use fast_output for more */
19380 
19381 			rack->r_fast_output = 1;
19382 			rack->r_ctl.fsb.m = sbsndmbuf(sb, (tp->snd_max - tp->snd_una), &rack->r_ctl.fsb.off);
19383 			rack->r_ctl.fsb.o_m_len = rack->r_ctl.fsb.m->m_len;
19384 			rack->r_ctl.fsb.tcp_flags = flags;
19385 			rack->r_ctl.fsb.left_to_send = orig_len - len;
19386 			if (hw_tls)
19387 				rack->r_ctl.fsb.hw_tls = 1;
19388 			else
19389 				rack->r_ctl.fsb.hw_tls = 0;
19390 			KASSERT((rack->r_ctl.fsb.left_to_send <= (sbavail(sb) - (tp->snd_max - tp->snd_una))),
19391 				("rack:%p left_to_send:%u sbavail:%u out:%u",
19392 				 rack, rack->r_ctl.fsb.left_to_send, sbavail(sb),
19393 				 (tp->snd_max - tp->snd_una)));
19394 			if (rack->r_ctl.fsb.left_to_send < segsiz) {
19395 				rack->r_fast_output = 0;
19396 			}
19397 			if (rack->r_fast_output) {
19398 				if (rack->r_ctl.fsb.left_to_send == (sbavail(sb) - (tp->snd_max - tp->snd_una)))
19399 					rack->r_ctl.fsb.rfo_apply_push = 1;
19400 				else
19401 					rack->r_ctl.fsb.rfo_apply_push = 0;
19402 				rack_log_fsb(rack, tp, so, flags,
19403 					     ipoptlen, orig_len, len, error,
19404 					     (rsm == NULL), optlen, __LINE__, 3);
19405 				error = 0;
19406 				ret = rack_fast_output(tp, rack, ts_val, cts, ms_cts, &tv, tot_len_this_send, &error);
19407 				if (ret >= 0)
19408 					return (ret);
19409 			        else if (error)
19410 					goto nomore;
19411 
19412 			}
19413 		}
19414 		goto again;
19415 	} else if (len) {
19416 		counter_u64_add(rack_unpaced_segments, 1);
19417 	}
19418 	/* Assure when we leave that snd_nxt will point to top */
19419 	if (SEQ_GT(tp->snd_max, tp->snd_nxt))
19420 		tp->snd_nxt = tp->snd_max;
19421 	rack_start_hpts_timer(rack, tp, cts, slot, tot_len_this_send, 0);
19422 #ifdef TCP_ACCOUNTING
19423 	crtsc = get_cyclecount() - ts_val;
19424 	if (tot_len_this_send) {
19425 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19426 			tp->tcp_cnt_counters[SND_OUT_DATA]++;
19427 		}
19428 		counter_u64_add(tcp_cnt_counters[SND_OUT_DATA], 1);
19429 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19430 			tp->tcp_proc_time[SND_OUT_DATA] += crtsc;
19431 		}
19432 		counter_u64_add(tcp_proc_time[SND_OUT_DATA], crtsc);
19433 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19434 			tp->tcp_cnt_counters[CNT_OF_MSS_OUT] += ((tot_len_this_send + segsiz - 1) /segsiz);
19435 		}
19436 		counter_u64_add(tcp_cnt_counters[CNT_OF_MSS_OUT], ((tot_len_this_send + segsiz - 1) /segsiz));
19437 	} else {
19438 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19439 			tp->tcp_cnt_counters[SND_OUT_ACK]++;
19440 		}
19441 		counter_u64_add(tcp_cnt_counters[SND_OUT_ACK], 1);
19442 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19443 			tp->tcp_proc_time[SND_OUT_ACK] += crtsc;
19444 		}
19445 		counter_u64_add(tcp_proc_time[SND_OUT_ACK], crtsc);
19446 	}
19447 	sched_unpin();
19448 #endif
19449 	if (error == ENOBUFS)
19450 		error = 0;
19451 	return (error);
19452 }
19453 
19454 static void
19455 rack_update_seg(struct tcp_rack *rack)
19456 {
19457 	uint32_t orig_val;
19458 
19459 	orig_val = rack->r_ctl.rc_pace_max_segs;
19460 	rack_set_pace_segments(rack->rc_tp, rack, __LINE__, NULL);
19461 	if (orig_val != rack->r_ctl.rc_pace_max_segs)
19462 		rack_log_pacing_delay_calc(rack, 0, 0, orig_val, 0, 0, 15, __LINE__, NULL, 0);
19463 }
19464 
19465 static void
19466 rack_mtu_change(struct tcpcb *tp)
19467 {
19468 	/*
19469 	 * The MSS may have changed
19470 	 */
19471 	struct tcp_rack *rack;
19472 	struct rack_sendmap *rsm;
19473 
19474 	rack = (struct tcp_rack *)tp->t_fb_ptr;
19475 	if (rack->r_ctl.rc_pace_min_segs != ctf_fixed_maxseg(tp)) {
19476 		/*
19477 		 * The MTU has changed we need to resend everything
19478 		 * since all we have sent is lost. We first fix
19479 		 * up the mtu though.
19480 		 */
19481 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
19482 		/* We treat this like a full retransmit timeout without the cwnd adjustment */
19483 		rack_remxt_tmr(tp);
19484 		rack->r_fast_output = 0;
19485 		rack->r_ctl.rc_out_at_rto = ctf_flight_size(tp,
19486 						rack->r_ctl.rc_sacked);
19487 		rack->r_ctl.rc_snd_max_at_rto = tp->snd_max;
19488 		rack->r_must_retran = 1;
19489 		/* Mark all inflight to needing to be rxt'd */
19490 		TAILQ_FOREACH(rsm, &rack->r_ctl.rc_tmap, r_tnext) {
19491 			rsm->r_flags |= RACK_MUST_RXT;
19492 		}
19493 	}
19494 	sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
19495 	/* We don't use snd_nxt to retransmit */
19496 	tp->snd_nxt = tp->snd_max;
19497 }
19498 
19499 static int
19500 rack_set_profile(struct tcp_rack *rack, int prof)
19501 {
19502 	int err = EINVAL;
19503 	if (prof == 1) {
19504 		/* pace_always=1 */
19505 		if (rack->rc_always_pace == 0) {
19506 			if (tcp_can_enable_pacing() == 0)
19507 				return (EBUSY);
19508 		}
19509 		rack->rc_always_pace = 1;
19510 		if (rack->use_fixed_rate || rack->gp_ready)
19511 			rack_set_cc_pacing(rack);
19512 		rack->rc_inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19513 		rack->rack_attempt_hdwr_pace = 0;
19514 		/* cmpack=1 */
19515 		if (rack_use_cmp_acks)
19516 			rack->r_use_cmp_ack = 1;
19517 		if (TCPS_HAVEESTABLISHED(rack->rc_tp->t_state) &&
19518 		    rack->r_use_cmp_ack)
19519 			rack->rc_inp->inp_flags2 |= INP_MBUF_ACKCMP;
19520 		/* scwnd=1 */
19521 		rack->rack_enable_scwnd = 1;
19522 		/* dynamic=100 */
19523 		rack->rc_gp_dyn_mul = 1;
19524 		/* gp_inc_ca */
19525 		rack->r_ctl.rack_per_of_gp_ca = 100;
19526 		/* rrr_conf=3 */
19527 		rack->r_rr_config = 3;
19528 		/* npush=2 */
19529 		rack->r_ctl.rc_no_push_at_mrtt = 2;
19530 		/* fillcw=1 */
19531 		rack->rc_pace_to_cwnd = 1;
19532 		rack->rc_pace_fill_if_rttin_range = 0;
19533 		rack->rtt_limit_mul = 0;
19534 		/* noprr=1 */
19535 		rack->rack_no_prr = 1;
19536 		/* lscwnd=1 */
19537 		rack->r_limit_scw = 1;
19538 		/* gp_inc_rec */
19539 		rack->r_ctl.rack_per_of_gp_rec = 90;
19540 		err = 0;
19541 
19542 	} else if (prof == 3) {
19543 		/* Same as profile one execept fill_cw becomes 2 (less aggressive set) */
19544 		/* pace_always=1 */
19545 		if (rack->rc_always_pace == 0) {
19546 			if (tcp_can_enable_pacing() == 0)
19547 				return (EBUSY);
19548 		}
19549 		rack->rc_always_pace = 1;
19550 		if (rack->use_fixed_rate || rack->gp_ready)
19551 			rack_set_cc_pacing(rack);
19552 		rack->rc_inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19553 		rack->rack_attempt_hdwr_pace = 0;
19554 		/* cmpack=1 */
19555 		if (rack_use_cmp_acks)
19556 			rack->r_use_cmp_ack = 1;
19557 		if (TCPS_HAVEESTABLISHED(rack->rc_tp->t_state) &&
19558 		    rack->r_use_cmp_ack)
19559 			rack->rc_inp->inp_flags2 |= INP_MBUF_ACKCMP;
19560 		/* scwnd=1 */
19561 		rack->rack_enable_scwnd = 1;
19562 		/* dynamic=100 */
19563 		rack->rc_gp_dyn_mul = 1;
19564 		/* gp_inc_ca */
19565 		rack->r_ctl.rack_per_of_gp_ca = 100;
19566 		/* rrr_conf=3 */
19567 		rack->r_rr_config = 3;
19568 		/* npush=2 */
19569 		rack->r_ctl.rc_no_push_at_mrtt = 2;
19570 		/* fillcw=2 */
19571 		rack->rc_pace_to_cwnd = 1;
19572 		rack->r_fill_less_agg = 1;
19573 		rack->rc_pace_fill_if_rttin_range = 0;
19574 		rack->rtt_limit_mul = 0;
19575 		/* noprr=1 */
19576 		rack->rack_no_prr = 1;
19577 		/* lscwnd=1 */
19578 		rack->r_limit_scw = 1;
19579 		/* gp_inc_rec */
19580 		rack->r_ctl.rack_per_of_gp_rec = 90;
19581 		err = 0;
19582 
19583 
19584 	} else if (prof == 2) {
19585 		/* cmpack=1 */
19586 		if (rack->rc_always_pace == 0) {
19587 			if (tcp_can_enable_pacing() == 0)
19588 				return (EBUSY);
19589 		}
19590 		rack->rc_always_pace = 1;
19591 		if (rack->use_fixed_rate || rack->gp_ready)
19592 			rack_set_cc_pacing(rack);
19593 		rack->r_use_cmp_ack = 1;
19594 		if (TCPS_HAVEESTABLISHED(rack->rc_tp->t_state))
19595 			rack->rc_inp->inp_flags2 |= INP_MBUF_ACKCMP;
19596 		/* pace_always=1 */
19597 		rack->rc_inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19598 		/* scwnd=1 */
19599 		rack->rack_enable_scwnd = 1;
19600 		/* dynamic=100 */
19601 		rack->rc_gp_dyn_mul = 1;
19602 		rack->r_ctl.rack_per_of_gp_ca = 100;
19603 		/* rrr_conf=3 */
19604 		rack->r_rr_config = 3;
19605 		/* npush=2 */
19606 		rack->r_ctl.rc_no_push_at_mrtt = 2;
19607 		/* fillcw=1 */
19608 		rack->rc_pace_to_cwnd = 1;
19609 		rack->rc_pace_fill_if_rttin_range = 0;
19610 		rack->rtt_limit_mul = 0;
19611 		/* noprr=1 */
19612 		rack->rack_no_prr = 1;
19613 		/* lscwnd=0 */
19614 		rack->r_limit_scw = 0;
19615 		err = 0;
19616 	} else if (prof == 0) {
19617 		/* This changes things back to the default settings */
19618 		err = 0;
19619 		if (rack->rc_always_pace) {
19620 			tcp_decrement_paced_conn();
19621 			rack_undo_cc_pacing(rack);
19622 			rack->rc_always_pace = 0;
19623 		}
19624 		if (rack_pace_every_seg && tcp_can_enable_pacing()) {
19625 			rack->rc_always_pace = 1;
19626 			if (rack->use_fixed_rate || rack->gp_ready)
19627 				rack_set_cc_pacing(rack);
19628 		} else
19629 			rack->rc_always_pace = 0;
19630 		if (rack_dsack_std_based & 0x1) {
19631 			/* Basically this means all rack timers are at least (srtt + 1/4 srtt) */
19632 			rack->rc_rack_tmr_std_based = 1;
19633 		}
19634 		if (rack_dsack_std_based & 0x2) {
19635 			/* Basically this means  rack timers are extended based on dsack by up to (2 * srtt) */
19636 			rack->rc_rack_use_dsack = 1;
19637 		}
19638 		if (rack_use_cmp_acks)
19639 			rack->r_use_cmp_ack = 1;
19640 		else
19641 			rack->r_use_cmp_ack = 0;
19642 		if (rack_disable_prr)
19643 			rack->rack_no_prr = 1;
19644 		else
19645 			rack->rack_no_prr = 0;
19646 		if (rack_gp_no_rec_chg)
19647 			rack->rc_gp_no_rec_chg = 1;
19648 		else
19649 			rack->rc_gp_no_rec_chg = 0;
19650 		if (rack_enable_mqueue_for_nonpaced || rack->r_use_cmp_ack) {
19651 			rack->r_mbuf_queue = 1;
19652 			if (TCPS_HAVEESTABLISHED(rack->rc_tp->t_state))
19653 				rack->rc_inp->inp_flags2 |= INP_MBUF_ACKCMP;
19654 			rack->rc_inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19655 		} else {
19656 			rack->r_mbuf_queue = 0;
19657 			rack->rc_inp->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
19658 		}
19659 		if (rack_enable_shared_cwnd)
19660 			rack->rack_enable_scwnd = 1;
19661 		else
19662 			rack->rack_enable_scwnd = 0;
19663 		if (rack_do_dyn_mul) {
19664 			/* When dynamic adjustment is on CA needs to start at 100% */
19665 			rack->rc_gp_dyn_mul = 1;
19666 			if (rack_do_dyn_mul >= 100)
19667 				rack->r_ctl.rack_per_of_gp_ca = rack_do_dyn_mul;
19668 		} else {
19669 			rack->r_ctl.rack_per_of_gp_ca = rack_per_of_gp_ca;
19670 			rack->rc_gp_dyn_mul = 0;
19671 		}
19672 		rack->r_rr_config = 0;
19673 		rack->r_ctl.rc_no_push_at_mrtt = 0;
19674 		rack->rc_pace_to_cwnd = 0;
19675 		rack->rc_pace_fill_if_rttin_range = 0;
19676 		rack->rtt_limit_mul = 0;
19677 
19678 		if (rack_enable_hw_pacing)
19679 			rack->rack_hdw_pace_ena = 1;
19680 		else
19681 			rack->rack_hdw_pace_ena = 0;
19682 		if (rack_disable_prr)
19683 			rack->rack_no_prr = 1;
19684 		else
19685 			rack->rack_no_prr = 0;
19686 		if (rack_limits_scwnd)
19687 			rack->r_limit_scw  = 1;
19688 		else
19689 			rack->r_limit_scw  = 0;
19690 		err = 0;
19691 	}
19692 	return (err);
19693 }
19694 
19695 static int
19696 rack_add_deferred_option(struct tcp_rack *rack, int sopt_name, uint64_t loptval)
19697 {
19698 	struct deferred_opt_list *dol;
19699 
19700 	dol = malloc(sizeof(struct deferred_opt_list),
19701 		     M_TCPFSB, M_NOWAIT|M_ZERO);
19702 	if (dol == NULL) {
19703 		/*
19704 		 * No space yikes -- fail out..
19705 		 */
19706 		return (0);
19707 	}
19708 	dol->optname = sopt_name;
19709 	dol->optval = loptval;
19710 	TAILQ_INSERT_TAIL(&rack->r_ctl.opt_list, dol, next);
19711 	return (1);
19712 }
19713 
19714 static int
19715 rack_process_option(struct tcpcb *tp, struct tcp_rack *rack, int sopt_name,
19716 		    uint32_t optval, uint64_t loptval)
19717 {
19718 	struct epoch_tracker et;
19719 	struct sockopt sopt;
19720 	struct cc_newreno_opts opt;
19721 	uint64_t val;
19722 	int error = 0;
19723 	uint16_t ca, ss;
19724 
19725 	switch (sopt_name) {
19726 
19727 	case TCP_RACK_DSACK_OPT:
19728 		RACK_OPTS_INC(tcp_rack_dsack_opt);
19729 		if (optval & 0x1) {
19730 			rack->rc_rack_tmr_std_based = 1;
19731 		} else {
19732 			rack->rc_rack_tmr_std_based = 0;
19733 		}
19734 		if (optval & 0x2) {
19735 			rack->rc_rack_use_dsack = 1;
19736 		} else {
19737 			rack->rc_rack_use_dsack = 0;
19738 		}
19739 		rack_log_dsack_event(rack, 5, __LINE__, 0, 0);
19740 		break;
19741 	case TCP_RACK_PACING_BETA:
19742 		RACK_OPTS_INC(tcp_rack_beta);
19743 		if (strcmp(tp->cc_algo->name, CCALGONAME_NEWRENO) != 0) {
19744 			/* This only works for newreno. */
19745 			error = EINVAL;
19746 			break;
19747 		}
19748 		if (rack->rc_pacing_cc_set) {
19749 			/*
19750 			 * Set them into the real CC module
19751 			 * whats in the rack pcb is the old values
19752 			 * to be used on restoral/
19753 			 */
19754 			sopt.sopt_dir = SOPT_SET;
19755 			opt.name = CC_NEWRENO_BETA;
19756 			opt.val = optval;
19757 			if (CC_ALGO(tp)->ctl_output != NULL)
19758 				error = CC_ALGO(tp)->ctl_output(tp->ccv, &sopt, &opt);
19759 			else {
19760 				error = ENOENT;
19761 				break;
19762 			}
19763 		} else {
19764 			/*
19765 			 * Not pacing yet so set it into our local
19766 			 * rack pcb storage.
19767 			 */
19768 			rack->r_ctl.rc_saved_beta.beta = optval;
19769 		}
19770 		break;
19771 	case TCP_RACK_TIMER_SLOP:
19772 		RACK_OPTS_INC(tcp_rack_timer_slop);
19773 		rack->r_ctl.timer_slop = optval;
19774 		if (rack->rc_tp->t_srtt) {
19775 			/*
19776 			 * If we have an SRTT lets update t_rxtcur
19777 			 * to have the new slop.
19778 			 */
19779 			RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
19780 					   rack_rto_min, rack_rto_max,
19781 					   rack->r_ctl.timer_slop);
19782 		}
19783 		break;
19784 	case TCP_RACK_PACING_BETA_ECN:
19785 		RACK_OPTS_INC(tcp_rack_beta_ecn);
19786 		if (strcmp(tp->cc_algo->name, CCALGONAME_NEWRENO) != 0) {
19787 			/* This only works for newreno. */
19788 			error = EINVAL;
19789 			break;
19790 		}
19791 		if (rack->rc_pacing_cc_set) {
19792 			/*
19793 			 * Set them into the real CC module
19794 			 * whats in the rack pcb is the old values
19795 			 * to be used on restoral/
19796 			 */
19797 			sopt.sopt_dir = SOPT_SET;
19798 			opt.name = CC_NEWRENO_BETA_ECN;
19799 			opt.val = optval;
19800 			if (CC_ALGO(tp)->ctl_output != NULL)
19801 				error = CC_ALGO(tp)->ctl_output(tp->ccv, &sopt, &opt);
19802 			else
19803 				error = ENOENT;
19804 		} else {
19805 			/*
19806 			 * Not pacing yet so set it into our local
19807 			 * rack pcb storage.
19808 			 */
19809 			rack->r_ctl.rc_saved_beta.beta_ecn = optval;
19810 			rack->r_ctl.rc_saved_beta.newreno_flags = CC_NEWRENO_BETA_ECN_ENABLED;
19811 		}
19812 		break;
19813 	case TCP_DEFER_OPTIONS:
19814 		RACK_OPTS_INC(tcp_defer_opt);
19815 		if (optval) {
19816 			if (rack->gp_ready) {
19817 				/* Too late */
19818 				error = EINVAL;
19819 				break;
19820 			}
19821 			rack->defer_options = 1;
19822 		} else
19823 			rack->defer_options = 0;
19824 		break;
19825 	case TCP_RACK_MEASURE_CNT:
19826 		RACK_OPTS_INC(tcp_rack_measure_cnt);
19827 		if (optval && (optval <= 0xff)) {
19828 			rack->r_ctl.req_measurements = optval;
19829 		} else
19830 			error = EINVAL;
19831 		break;
19832 	case TCP_REC_ABC_VAL:
19833 		RACK_OPTS_INC(tcp_rec_abc_val);
19834 		if (optval > 0)
19835 			rack->r_use_labc_for_rec = 1;
19836 		else
19837 			rack->r_use_labc_for_rec = 0;
19838 		break;
19839 	case TCP_RACK_ABC_VAL:
19840 		RACK_OPTS_INC(tcp_rack_abc_val);
19841 		if ((optval > 0) && (optval < 255))
19842 			rack->rc_labc = optval;
19843 		else
19844 			error = EINVAL;
19845 		break;
19846 	case TCP_HDWR_UP_ONLY:
19847 		RACK_OPTS_INC(tcp_pacing_up_only);
19848 		if (optval)
19849 			rack->r_up_only = 1;
19850 		else
19851 			rack->r_up_only = 0;
19852 		break;
19853 	case TCP_PACING_RATE_CAP:
19854 		RACK_OPTS_INC(tcp_pacing_rate_cap);
19855 		rack->r_ctl.bw_rate_cap = loptval;
19856 		break;
19857 	case TCP_RACK_PROFILE:
19858 		RACK_OPTS_INC(tcp_profile);
19859 		error = rack_set_profile(rack, optval);
19860 		break;
19861 	case TCP_USE_CMP_ACKS:
19862 		RACK_OPTS_INC(tcp_use_cmp_acks);
19863 		if ((optval == 0) && (rack->rc_inp->inp_flags2 & INP_MBUF_ACKCMP)) {
19864 			/* You can't turn it off once its on! */
19865 			error = EINVAL;
19866 		} else if ((optval == 1) && (rack->r_use_cmp_ack == 0)) {
19867 			rack->r_use_cmp_ack = 1;
19868 			rack->r_mbuf_queue = 1;
19869 			tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19870 		}
19871 		if (rack->r_use_cmp_ack && TCPS_HAVEESTABLISHED(tp->t_state))
19872 			rack->rc_inp->inp_flags2 |= INP_MBUF_ACKCMP;
19873 		break;
19874 	case TCP_SHARED_CWND_TIME_LIMIT:
19875 		RACK_OPTS_INC(tcp_lscwnd);
19876 		if (optval)
19877 			rack->r_limit_scw = 1;
19878 		else
19879 			rack->r_limit_scw = 0;
19880 		break;
19881  	case TCP_RACK_PACE_TO_FILL:
19882 		RACK_OPTS_INC(tcp_fillcw);
19883 		if (optval == 0)
19884 			rack->rc_pace_to_cwnd = 0;
19885 		else {
19886 			rack->rc_pace_to_cwnd = 1;
19887 			if (optval > 1)
19888 				rack->r_fill_less_agg = 1;
19889 		}
19890 		if ((optval >= rack_gp_rtt_maxmul) &&
19891 		    rack_gp_rtt_maxmul &&
19892 		    (optval < 0xf)) {
19893 			rack->rc_pace_fill_if_rttin_range = 1;
19894 			rack->rtt_limit_mul = optval;
19895 		} else {
19896 			rack->rc_pace_fill_if_rttin_range = 0;
19897 			rack->rtt_limit_mul = 0;
19898 		}
19899 		break;
19900 	case TCP_RACK_NO_PUSH_AT_MAX:
19901 		RACK_OPTS_INC(tcp_npush);
19902 		if (optval == 0)
19903 			rack->r_ctl.rc_no_push_at_mrtt = 0;
19904 		else if (optval < 0xff)
19905 			rack->r_ctl.rc_no_push_at_mrtt = optval;
19906 		else
19907 			error = EINVAL;
19908 		break;
19909 	case TCP_SHARED_CWND_ENABLE:
19910 		RACK_OPTS_INC(tcp_rack_scwnd);
19911 		if (optval == 0)
19912 			rack->rack_enable_scwnd = 0;
19913 		else
19914 			rack->rack_enable_scwnd = 1;
19915 		break;
19916 	case TCP_RACK_MBUF_QUEUE:
19917 		/* Now do we use the LRO mbuf-queue feature */
19918 		RACK_OPTS_INC(tcp_rack_mbufq);
19919 		if (optval || rack->r_use_cmp_ack)
19920 			rack->r_mbuf_queue = 1;
19921 		else
19922 			rack->r_mbuf_queue = 0;
19923 		if  (rack->r_mbuf_queue || rack->rc_always_pace || rack->r_use_cmp_ack)
19924 			tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19925 		else
19926 			tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
19927 		break;
19928 	case TCP_RACK_NONRXT_CFG_RATE:
19929 		RACK_OPTS_INC(tcp_rack_cfg_rate);
19930 		if (optval == 0)
19931 			rack->rack_rec_nonrxt_use_cr = 0;
19932 		else
19933 			rack->rack_rec_nonrxt_use_cr = 1;
19934 		break;
19935 	case TCP_NO_PRR:
19936 		RACK_OPTS_INC(tcp_rack_noprr);
19937 		if (optval == 0)
19938 			rack->rack_no_prr = 0;
19939 		else if (optval == 1)
19940 			rack->rack_no_prr = 1;
19941 		else if (optval == 2)
19942 			rack->no_prr_addback = 1;
19943 		else
19944 			error = EINVAL;
19945 		break;
19946 	case TCP_TIMELY_DYN_ADJ:
19947 		RACK_OPTS_INC(tcp_timely_dyn);
19948 		if (optval == 0)
19949 			rack->rc_gp_dyn_mul = 0;
19950 		else {
19951 			rack->rc_gp_dyn_mul = 1;
19952 			if (optval >= 100) {
19953 				/*
19954 				 * If the user sets something 100 or more
19955 				 * its the gp_ca value.
19956 				 */
19957 				rack->r_ctl.rack_per_of_gp_ca  = optval;
19958 			}
19959 		}
19960 		break;
19961 	case TCP_RACK_DO_DETECTION:
19962 		RACK_OPTS_INC(tcp_rack_do_detection);
19963 		if (optval == 0)
19964 			rack->do_detection = 0;
19965 		else
19966 			rack->do_detection = 1;
19967 		break;
19968 	case TCP_RACK_TLP_USE:
19969 		if ((optval < TLP_USE_ID) || (optval > TLP_USE_TWO_TWO)) {
19970 			error = EINVAL;
19971 			break;
19972 		}
19973 		RACK_OPTS_INC(tcp_tlp_use);
19974 		rack->rack_tlp_threshold_use = optval;
19975 		break;
19976 	case TCP_RACK_TLP_REDUCE:
19977 		/* RACK TLP cwnd reduction (bool) */
19978 		RACK_OPTS_INC(tcp_rack_tlp_reduce);
19979 		rack->r_ctl.rc_tlp_cwnd_reduce = optval;
19980 		break;
19981 	/*  Pacing related ones */
19982 	case TCP_RACK_PACE_ALWAYS:
19983 		/*
19984 		 * zero is old rack method, 1 is new
19985 		 * method using a pacing rate.
19986 		 */
19987 		RACK_OPTS_INC(tcp_rack_pace_always);
19988 		if (optval > 0) {
19989 			if (rack->rc_always_pace) {
19990 				error = EALREADY;
19991 				break;
19992 			} else if (tcp_can_enable_pacing()) {
19993 				rack->rc_always_pace = 1;
19994 				if (rack->use_fixed_rate || rack->gp_ready)
19995 					rack_set_cc_pacing(rack);
19996 			}
19997 			else {
19998 				error = ENOSPC;
19999 				break;
20000 			}
20001 		} else {
20002 			if (rack->rc_always_pace) {
20003 				tcp_decrement_paced_conn();
20004 				rack->rc_always_pace = 0;
20005 				rack_undo_cc_pacing(rack);
20006 			}
20007 		}
20008 		if  (rack->r_mbuf_queue || rack->rc_always_pace || rack->r_use_cmp_ack)
20009 			tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
20010 		else
20011 			tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
20012 		/* A rate may be set irate or other, if so set seg size */
20013 		rack_update_seg(rack);
20014 		break;
20015 	case TCP_BBR_RACK_INIT_RATE:
20016 		RACK_OPTS_INC(tcp_initial_rate);
20017 		val = optval;
20018 		/* Change from kbits per second to bytes per second */
20019 		val *= 1000;
20020 		val /= 8;
20021 		rack->r_ctl.init_rate = val;
20022 		if (rack->rc_init_win != rack_default_init_window) {
20023 			uint32_t win, snt;
20024 
20025 			/*
20026 			 * Options don't always get applied
20027 			 * in the order you think. So in order
20028 			 * to assure we update a cwnd we need
20029 			 * to check and see if we are still
20030 			 * where we should raise the cwnd.
20031 			 */
20032 			win = rc_init_window(rack);
20033 			if (SEQ_GT(tp->snd_max, tp->iss))
20034 				snt = tp->snd_max - tp->iss;
20035 			else
20036 				snt = 0;
20037 			if ((snt < win) &&
20038 			    (tp->snd_cwnd < win))
20039 				tp->snd_cwnd = win;
20040 		}
20041 		if (rack->rc_always_pace)
20042 			rack_update_seg(rack);
20043 		break;
20044 	case TCP_BBR_IWINTSO:
20045 		RACK_OPTS_INC(tcp_initial_win);
20046 		if (optval && (optval <= 0xff)) {
20047 			uint32_t win, snt;
20048 
20049 			rack->rc_init_win = optval;
20050 			win = rc_init_window(rack);
20051 			if (SEQ_GT(tp->snd_max, tp->iss))
20052 				snt = tp->snd_max - tp->iss;
20053 			else
20054 				snt = 0;
20055 			if ((snt < win) &&
20056 			    (tp->t_srtt |
20057 #ifdef NETFLIX_PEAKRATE
20058 			     tp->t_maxpeakrate |
20059 #endif
20060 			     rack->r_ctl.init_rate)) {
20061 				/*
20062 				 * We are not past the initial window
20063 				 * and we have some bases for pacing,
20064 				 * so we need to possibly adjust up
20065 				 * the cwnd. Note even if we don't set
20066 				 * the cwnd, its still ok to raise the rc_init_win
20067 				 * which can be used coming out of idle when we
20068 				 * would have a rate.
20069 				 */
20070 				if (tp->snd_cwnd < win)
20071 					tp->snd_cwnd = win;
20072 			}
20073 			if (rack->rc_always_pace)
20074 				rack_update_seg(rack);
20075 		} else
20076 			error = EINVAL;
20077 		break;
20078 	case TCP_RACK_FORCE_MSEG:
20079 		RACK_OPTS_INC(tcp_rack_force_max_seg);
20080 		if (optval)
20081 			rack->rc_force_max_seg = 1;
20082 		else
20083 			rack->rc_force_max_seg = 0;
20084 		break;
20085 	case TCP_RACK_PACE_MAX_SEG:
20086 		/* Max segments size in a pace in bytes */
20087 		RACK_OPTS_INC(tcp_rack_max_seg);
20088 		rack->rc_user_set_max_segs = optval;
20089 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
20090 		break;
20091 	case TCP_RACK_PACE_RATE_REC:
20092 		/* Set the fixed pacing rate in Bytes per second ca */
20093 		RACK_OPTS_INC(tcp_rack_pace_rate_rec);
20094 		rack->r_ctl.rc_fixed_pacing_rate_rec = optval;
20095 		if (rack->r_ctl.rc_fixed_pacing_rate_ca == 0)
20096 			rack->r_ctl.rc_fixed_pacing_rate_ca = optval;
20097 		if (rack->r_ctl.rc_fixed_pacing_rate_ss == 0)
20098 			rack->r_ctl.rc_fixed_pacing_rate_ss = optval;
20099 		rack->use_fixed_rate = 1;
20100 		if (rack->rc_always_pace)
20101 			rack_set_cc_pacing(rack);
20102 		rack_log_pacing_delay_calc(rack,
20103 					   rack->r_ctl.rc_fixed_pacing_rate_ss,
20104 					   rack->r_ctl.rc_fixed_pacing_rate_ca,
20105 					   rack->r_ctl.rc_fixed_pacing_rate_rec, 0, 0, 8,
20106 					   __LINE__, NULL,0);
20107 		break;
20108 
20109 	case TCP_RACK_PACE_RATE_SS:
20110 		/* Set the fixed pacing rate in Bytes per second ca */
20111 		RACK_OPTS_INC(tcp_rack_pace_rate_ss);
20112 		rack->r_ctl.rc_fixed_pacing_rate_ss = optval;
20113 		if (rack->r_ctl.rc_fixed_pacing_rate_ca == 0)
20114 			rack->r_ctl.rc_fixed_pacing_rate_ca = optval;
20115 		if (rack->r_ctl.rc_fixed_pacing_rate_rec == 0)
20116 			rack->r_ctl.rc_fixed_pacing_rate_rec = optval;
20117 		rack->use_fixed_rate = 1;
20118 		if (rack->rc_always_pace)
20119 			rack_set_cc_pacing(rack);
20120 		rack_log_pacing_delay_calc(rack,
20121 					   rack->r_ctl.rc_fixed_pacing_rate_ss,
20122 					   rack->r_ctl.rc_fixed_pacing_rate_ca,
20123 					   rack->r_ctl.rc_fixed_pacing_rate_rec, 0, 0, 8,
20124 					   __LINE__, NULL, 0);
20125 		break;
20126 
20127 	case TCP_RACK_PACE_RATE_CA:
20128 		/* Set the fixed pacing rate in Bytes per second ca */
20129 		RACK_OPTS_INC(tcp_rack_pace_rate_ca);
20130 		rack->r_ctl.rc_fixed_pacing_rate_ca = optval;
20131 		if (rack->r_ctl.rc_fixed_pacing_rate_ss == 0)
20132 			rack->r_ctl.rc_fixed_pacing_rate_ss = optval;
20133 		if (rack->r_ctl.rc_fixed_pacing_rate_rec == 0)
20134 			rack->r_ctl.rc_fixed_pacing_rate_rec = optval;
20135 		rack->use_fixed_rate = 1;
20136 		if (rack->rc_always_pace)
20137 			rack_set_cc_pacing(rack);
20138 		rack_log_pacing_delay_calc(rack,
20139 					   rack->r_ctl.rc_fixed_pacing_rate_ss,
20140 					   rack->r_ctl.rc_fixed_pacing_rate_ca,
20141 					   rack->r_ctl.rc_fixed_pacing_rate_rec, 0, 0, 8,
20142 					   __LINE__, NULL, 0);
20143 		break;
20144 	case TCP_RACK_GP_INCREASE_REC:
20145 		RACK_OPTS_INC(tcp_gp_inc_rec);
20146 		rack->r_ctl.rack_per_of_gp_rec = optval;
20147 		rack_log_pacing_delay_calc(rack,
20148 					   rack->r_ctl.rack_per_of_gp_ss,
20149 					   rack->r_ctl.rack_per_of_gp_ca,
20150 					   rack->r_ctl.rack_per_of_gp_rec, 0, 0, 1,
20151 					   __LINE__, NULL, 0);
20152 		break;
20153 	case TCP_RACK_GP_INCREASE_CA:
20154 		RACK_OPTS_INC(tcp_gp_inc_ca);
20155 		ca = optval;
20156 		if (ca < 100) {
20157 			/*
20158 			 * We don't allow any reduction
20159 			 * over the GP b/w.
20160 			 */
20161 			error = EINVAL;
20162 			break;
20163 		}
20164 		rack->r_ctl.rack_per_of_gp_ca = ca;
20165 		rack_log_pacing_delay_calc(rack,
20166 					   rack->r_ctl.rack_per_of_gp_ss,
20167 					   rack->r_ctl.rack_per_of_gp_ca,
20168 					   rack->r_ctl.rack_per_of_gp_rec, 0, 0, 1,
20169 					   __LINE__, NULL, 0);
20170 		break;
20171 	case TCP_RACK_GP_INCREASE_SS:
20172 		RACK_OPTS_INC(tcp_gp_inc_ss);
20173 		ss = optval;
20174 		if (ss < 100) {
20175 			/*
20176 			 * We don't allow any reduction
20177 			 * over the GP b/w.
20178 			 */
20179 			error = EINVAL;
20180 			break;
20181 		}
20182 		rack->r_ctl.rack_per_of_gp_ss = ss;
20183 		rack_log_pacing_delay_calc(rack,
20184 					   rack->r_ctl.rack_per_of_gp_ss,
20185 					   rack->r_ctl.rack_per_of_gp_ca,
20186 					   rack->r_ctl.rack_per_of_gp_rec, 0, 0, 1,
20187 					   __LINE__, NULL, 0);
20188 		break;
20189 	case TCP_RACK_RR_CONF:
20190 		RACK_OPTS_INC(tcp_rack_rrr_no_conf_rate);
20191 		if (optval && optval <= 3)
20192 			rack->r_rr_config = optval;
20193 		else
20194 			rack->r_rr_config = 0;
20195 		break;
20196 	case TCP_HDWR_RATE_CAP:
20197 		RACK_OPTS_INC(tcp_hdwr_rate_cap);
20198 		if (optval) {
20199 			if (rack->r_rack_hw_rate_caps == 0)
20200 				rack->r_rack_hw_rate_caps = 1;
20201 			else
20202 				error = EALREADY;
20203 		} else {
20204 			rack->r_rack_hw_rate_caps = 0;
20205 		}
20206 		break;
20207 	case TCP_BBR_HDWR_PACE:
20208 		RACK_OPTS_INC(tcp_hdwr_pacing);
20209 		if (optval){
20210 			if (rack->rack_hdrw_pacing == 0) {
20211 				rack->rack_hdw_pace_ena = 1;
20212 				rack->rack_attempt_hdwr_pace = 0;
20213 			} else
20214 				error = EALREADY;
20215 		} else {
20216 			rack->rack_hdw_pace_ena = 0;
20217 #ifdef RATELIMIT
20218 			if (rack->r_ctl.crte != NULL) {
20219 				rack->rack_hdrw_pacing = 0;
20220 				rack->rack_attempt_hdwr_pace = 0;
20221 				tcp_rel_pacing_rate(rack->r_ctl.crte, tp);
20222 				rack->r_ctl.crte = NULL;
20223 			}
20224 #endif
20225 		}
20226 		break;
20227 	/*  End Pacing related ones */
20228 	case TCP_RACK_PRR_SENDALOT:
20229 		/* Allow PRR to send more than one seg */
20230 		RACK_OPTS_INC(tcp_rack_prr_sendalot);
20231 		rack->r_ctl.rc_prr_sendalot = optval;
20232 		break;
20233 	case TCP_RACK_MIN_TO:
20234 		/* Minimum time between rack t-o's in ms */
20235 		RACK_OPTS_INC(tcp_rack_min_to);
20236 		rack->r_ctl.rc_min_to = optval;
20237 		break;
20238 	case TCP_RACK_EARLY_SEG:
20239 		/* If early recovery max segments */
20240 		RACK_OPTS_INC(tcp_rack_early_seg);
20241 		rack->r_ctl.rc_early_recovery_segs = optval;
20242 		break;
20243 	case TCP_RACK_ENABLE_HYSTART:
20244 	{
20245 		struct sockopt sopt;
20246 		struct cc_newreno_opts opt;
20247 
20248 		sopt.sopt_valsize = sizeof(struct cc_newreno_opts);
20249 		sopt.sopt_dir = SOPT_SET;
20250 		opt.name = CC_NEWRENO_ENABLE_HYSTART;
20251 		opt.val = optval;
20252 		if (CC_ALGO(tp)->ctl_output != NULL)
20253 			error = CC_ALGO(tp)->ctl_output(tp->ccv, &sopt, &opt);
20254 		else
20255 			error = EINVAL;
20256 	}
20257 	break;
20258 	case TCP_RACK_REORD_THRESH:
20259 		/* RACK reorder threshold (shift amount) */
20260 		RACK_OPTS_INC(tcp_rack_reord_thresh);
20261 		if ((optval > 0) && (optval < 31))
20262 			rack->r_ctl.rc_reorder_shift = optval;
20263 		else
20264 			error = EINVAL;
20265 		break;
20266 	case TCP_RACK_REORD_FADE:
20267 		/* Does reordering fade after ms time */
20268 		RACK_OPTS_INC(tcp_rack_reord_fade);
20269 		rack->r_ctl.rc_reorder_fade = optval;
20270 		break;
20271 	case TCP_RACK_TLP_THRESH:
20272 		/* RACK TLP theshold i.e. srtt+(srtt/N) */
20273 		RACK_OPTS_INC(tcp_rack_tlp_thresh);
20274 		if (optval)
20275 			rack->r_ctl.rc_tlp_threshold = optval;
20276 		else
20277 			error = EINVAL;
20278 		break;
20279 	case TCP_BBR_USE_RACK_RR:
20280 		RACK_OPTS_INC(tcp_rack_rr);
20281 		if (optval)
20282 			rack->use_rack_rr = 1;
20283 		else
20284 			rack->use_rack_rr = 0;
20285 		break;
20286 	case TCP_FAST_RSM_HACK:
20287 		RACK_OPTS_INC(tcp_rack_fastrsm_hack);
20288 		if (optval)
20289 			rack->fast_rsm_hack = 1;
20290 		else
20291 			rack->fast_rsm_hack = 0;
20292 		break;
20293 	case TCP_RACK_PKT_DELAY:
20294 		/* RACK added ms i.e. rack-rtt + reord + N */
20295 		RACK_OPTS_INC(tcp_rack_pkt_delay);
20296 		rack->r_ctl.rc_pkt_delay = optval;
20297 		break;
20298 	case TCP_DELACK:
20299 		RACK_OPTS_INC(tcp_rack_delayed_ack);
20300 		if (optval == 0)
20301 			tp->t_delayed_ack = 0;
20302 		else
20303 			tp->t_delayed_ack = 1;
20304 		if (tp->t_flags & TF_DELACK) {
20305 			tp->t_flags &= ~TF_DELACK;
20306 			tp->t_flags |= TF_ACKNOW;
20307 			NET_EPOCH_ENTER(et);
20308 			rack_output(tp);
20309 			NET_EPOCH_EXIT(et);
20310 		}
20311 		break;
20312 
20313 	case TCP_BBR_RACK_RTT_USE:
20314 		RACK_OPTS_INC(tcp_rack_rtt_use);
20315 		if ((optval != USE_RTT_HIGH) &&
20316 		    (optval != USE_RTT_LOW) &&
20317 		    (optval != USE_RTT_AVG))
20318 			error = EINVAL;
20319 		else
20320 			rack->r_ctl.rc_rate_sample_method = optval;
20321 		break;
20322 	case TCP_DATA_AFTER_CLOSE:
20323 		RACK_OPTS_INC(tcp_data_after_close);
20324 		if (optval)
20325 			rack->rc_allow_data_af_clo = 1;
20326 		else
20327 			rack->rc_allow_data_af_clo = 0;
20328 		break;
20329 	default:
20330 		break;
20331 	}
20332 #ifdef NETFLIX_STATS
20333 	tcp_log_socket_option(tp, sopt_name, optval, error);
20334 #endif
20335 	return (error);
20336 }
20337 
20338 
20339 static void
20340 rack_apply_deferred_options(struct tcp_rack *rack)
20341 {
20342 	struct deferred_opt_list *dol, *sdol;
20343 	uint32_t s_optval;
20344 
20345 	TAILQ_FOREACH_SAFE(dol, &rack->r_ctl.opt_list, next, sdol) {
20346 		TAILQ_REMOVE(&rack->r_ctl.opt_list, dol, next);
20347 		/* Disadvantage of deferal is you loose the error return */
20348 		s_optval = (uint32_t)dol->optval;
20349 		(void)rack_process_option(rack->rc_tp, rack, dol->optname, s_optval, dol->optval);
20350 		free(dol, M_TCPDO);
20351 	}
20352 }
20353 
20354 static void
20355 rack_hw_tls_change(struct tcpcb *tp, int chg)
20356 {
20357 	/*
20358 	 * HW tls state has changed.. fix all
20359 	 * rsm's in flight.
20360 	 */
20361 	struct tcp_rack *rack;
20362 	struct rack_sendmap *rsm;
20363 
20364 	rack = (struct tcp_rack *)tp->t_fb_ptr;
20365 	RB_FOREACH(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
20366 		if (chg)
20367 			rsm->r_hw_tls = 1;
20368 		else
20369 			rsm->r_hw_tls = 0;
20370 	}
20371 	if (chg)
20372 		rack->r_ctl.fsb.hw_tls = 1;
20373 	else
20374 		rack->r_ctl.fsb.hw_tls = 0;
20375 }
20376 
20377 static int
20378 rack_pru_options(struct tcpcb *tp, int flags)
20379 {
20380 	if (flags & PRUS_OOB)
20381 		return (EOPNOTSUPP);
20382 	return (0);
20383 }
20384 
20385 static struct tcp_function_block __tcp_rack = {
20386 	.tfb_tcp_block_name = __XSTRING(STACKNAME),
20387 	.tfb_tcp_output = rack_output,
20388 	.tfb_do_queued_segments = ctf_do_queued_segments,
20389 	.tfb_do_segment_nounlock = rack_do_segment_nounlock,
20390 	.tfb_tcp_do_segment = rack_do_segment,
20391 	.tfb_tcp_ctloutput = rack_ctloutput,
20392 	.tfb_tcp_fb_init = rack_init,
20393 	.tfb_tcp_fb_fini = rack_fini,
20394 	.tfb_tcp_timer_stop_all = rack_stopall,
20395 	.tfb_tcp_timer_activate = rack_timer_activate,
20396 	.tfb_tcp_timer_active = rack_timer_active,
20397 	.tfb_tcp_timer_stop = rack_timer_stop,
20398 	.tfb_tcp_rexmit_tmr = rack_remxt_tmr,
20399 	.tfb_tcp_handoff_ok = rack_handoff_ok,
20400 	.tfb_tcp_mtu_chg = rack_mtu_change,
20401 	.tfb_pru_options = rack_pru_options,
20402 	.tfb_hwtls_change = rack_hw_tls_change,
20403 };
20404 
20405 /*
20406  * rack_ctloutput() must drop the inpcb lock before performing copyin on
20407  * socket option arguments.  When it re-acquires the lock after the copy, it
20408  * has to revalidate that the connection is still valid for the socket
20409  * option.
20410  */
20411 static int
20412 rack_set_sockopt(struct socket *so, struct sockopt *sopt,
20413     struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack)
20414 {
20415 #ifdef INET6
20416 	struct ip6_hdr *ip6 = (struct ip6_hdr *)rack->r_ctl.fsb.tcp_ip_hdr;
20417 #endif
20418 #ifdef INET
20419 	struct ip *ip = (struct ip *)rack->r_ctl.fsb.tcp_ip_hdr;
20420 #endif
20421 	uint64_t loptval;
20422 	int32_t error = 0, optval;
20423 
20424 	switch (sopt->sopt_level) {
20425 #ifdef INET6
20426 	case IPPROTO_IPV6:
20427 		MPASS(inp->inp_vflag & INP_IPV6PROTO);
20428 		switch (sopt->sopt_name) {
20429 		case IPV6_USE_MIN_MTU:
20430 			tcp6_use_min_mtu(tp);
20431 			break;
20432 		case IPV6_TCLASS:
20433 			/*
20434 			 * The DSCP codepoint has changed, update the fsb.
20435 			 */
20436 			ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
20437 			    (rack->rc_inp->inp_flow & IPV6_FLOWINFO_MASK);
20438 			break;
20439 		}
20440 		INP_WUNLOCK(inp);
20441 		return (0);
20442 #endif
20443 #ifdef INET
20444 	case IPPROTO_IP:
20445 		switch (sopt->sopt_name) {
20446 		case IP_TOS:
20447 			/*
20448 			 * The DSCP codepoint has changed, update the fsb.
20449 			 */
20450 			ip->ip_tos = rack->rc_inp->inp_ip_tos;
20451 			break;
20452 		case IP_TTL:
20453 			/*
20454 			 * The TTL has changed, update the fsb.
20455 			 */
20456 			ip->ip_ttl = rack->rc_inp->inp_ip_ttl;
20457 			break;
20458 		}
20459 		INP_WUNLOCK(inp);
20460 		return (0);
20461 #endif
20462 	}
20463 
20464 	switch (sopt->sopt_name) {
20465 	case TCP_RACK_TLP_REDUCE:		/*  URL:tlp_reduce */
20466 	/*  Pacing related ones */
20467 	case TCP_RACK_PACE_ALWAYS:		/*  URL:pace_always */
20468 	case TCP_BBR_RACK_INIT_RATE:		/*  URL:irate */
20469 	case TCP_BBR_IWINTSO:			/*  URL:tso_iwin */
20470 	case TCP_RACK_PACE_MAX_SEG:		/*  URL:pace_max_seg */
20471 	case TCP_RACK_FORCE_MSEG:		/*  URL:force_max_seg */
20472 	case TCP_RACK_PACE_RATE_CA:		/*  URL:pr_ca */
20473 	case TCP_RACK_PACE_RATE_SS:		/*  URL:pr_ss*/
20474 	case TCP_RACK_PACE_RATE_REC:		/*  URL:pr_rec */
20475 	case TCP_RACK_GP_INCREASE_CA:		/*  URL:gp_inc_ca */
20476 	case TCP_RACK_GP_INCREASE_SS:		/*  URL:gp_inc_ss */
20477 	case TCP_RACK_GP_INCREASE_REC:		/*  URL:gp_inc_rec */
20478 	case TCP_RACK_RR_CONF:			/*  URL:rrr_conf */
20479 	case TCP_BBR_HDWR_PACE:			/*  URL:hdwrpace */
20480 	case TCP_HDWR_RATE_CAP:			/*  URL:hdwrcap boolean */
20481 	case TCP_PACING_RATE_CAP:		/*  URL:cap  -- used by side-channel */
20482 	case TCP_HDWR_UP_ONLY:			/*  URL:uponly -- hardware pacing  boolean */
20483        /* End pacing related */
20484 	case TCP_FAST_RSM_HACK:			/*  URL:frsm_hack */
20485 	case TCP_DELACK:			/*  URL:delack (in base TCP i.e. tcp_hints along with cc etc ) */
20486 	case TCP_RACK_PRR_SENDALOT:		/*  URL:prr_sendalot */
20487 	case TCP_RACK_MIN_TO:			/*  URL:min_to */
20488 	case TCP_RACK_EARLY_SEG:		/*  URL:early_seg */
20489 	case TCP_RACK_REORD_THRESH:		/*  URL:reord_thresh */
20490 	case TCP_RACK_REORD_FADE:		/*  URL:reord_fade */
20491 	case TCP_RACK_TLP_THRESH:		/*  URL:tlp_thresh */
20492 	case TCP_RACK_PKT_DELAY:		/*  URL:pkt_delay */
20493 	case TCP_RACK_TLP_USE:			/*  URL:tlp_use */
20494 	case TCP_BBR_RACK_RTT_USE:		/*  URL:rttuse */
20495 	case TCP_BBR_USE_RACK_RR:		/*  URL:rackrr */
20496 	case TCP_RACK_DO_DETECTION:		/*  URL:detect */
20497 	case TCP_NO_PRR:			/*  URL:noprr */
20498 	case TCP_TIMELY_DYN_ADJ:      		/*  URL:dynamic */
20499 	case TCP_DATA_AFTER_CLOSE:		/*  no URL */
20500 	case TCP_RACK_NONRXT_CFG_RATE:		/*  URL:nonrxtcr */
20501 	case TCP_SHARED_CWND_ENABLE:		/*  URL:scwnd */
20502 	case TCP_RACK_MBUF_QUEUE:		/*  URL:mqueue */
20503 	case TCP_RACK_NO_PUSH_AT_MAX:		/*  URL:npush */
20504 	case TCP_RACK_PACE_TO_FILL:		/*  URL:fillcw */
20505 	case TCP_SHARED_CWND_TIME_LIMIT:	/*  URL:lscwnd */
20506 	case TCP_RACK_PROFILE:			/*  URL:profile */
20507 	case TCP_USE_CMP_ACKS:			/*  URL:cmpack */
20508 	case TCP_RACK_ABC_VAL:			/*  URL:labc */
20509 	case TCP_REC_ABC_VAL:			/*  URL:reclabc */
20510 	case TCP_RACK_MEASURE_CNT:		/*  URL:measurecnt */
20511 	case TCP_DEFER_OPTIONS:			/*  URL:defer */
20512 	case TCP_RACK_DSACK_OPT:		/*  URL:dsack */
20513 	case TCP_RACK_PACING_BETA:		/*  URL:pacing_beta */
20514 	case TCP_RACK_PACING_BETA_ECN:		/*  URL:pacing_beta_ecn */
20515 	case TCP_RACK_TIMER_SLOP:		/*  URL:timer_slop */
20516 	case TCP_RACK_ENABLE_HYSTART:		/*  URL:hystart */
20517 		break;
20518 	default:
20519 		/* Filter off all unknown options to the base stack */
20520 		return (tcp_default_ctloutput(so, sopt, inp, tp));
20521 		break;
20522 	}
20523 	INP_WUNLOCK(inp);
20524 	if (sopt->sopt_name == TCP_PACING_RATE_CAP) {
20525 		error = sooptcopyin(sopt, &loptval, sizeof(loptval), sizeof(loptval));
20526 		/*
20527 		 * We truncate it down to 32 bits for the socket-option trace this
20528 		 * means rates > 34Gbps won't show right, but thats probably ok.
20529 		 */
20530 		optval = (uint32_t)loptval;
20531 	} else {
20532 		error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
20533 		/* Save it in 64 bit form too */
20534 		loptval = optval;
20535 	}
20536 	if (error)
20537 		return (error);
20538 	INP_WLOCK(inp);
20539 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
20540 		INP_WUNLOCK(inp);
20541 		return (ECONNRESET);
20542 	}
20543 	if (tp->t_fb != &__tcp_rack) {
20544 		INP_WUNLOCK(inp);
20545 		return (ENOPROTOOPT);
20546 	}
20547 	if (rack->defer_options && (rack->gp_ready == 0) &&
20548 	    (sopt->sopt_name != TCP_DEFER_OPTIONS) &&
20549 	    (sopt->sopt_name != TCP_RACK_PACING_BETA) &&
20550 	    (sopt->sopt_name != TCP_RACK_PACING_BETA_ECN) &&
20551 	    (sopt->sopt_name != TCP_RACK_MEASURE_CNT)) {
20552 		/* Options are beind deferred */
20553 		if (rack_add_deferred_option(rack, sopt->sopt_name, loptval)) {
20554 			INP_WUNLOCK(inp);
20555 			return (0);
20556 		} else {
20557 			/* No memory to defer, fail */
20558 			INP_WUNLOCK(inp);
20559 			return (ENOMEM);
20560 		}
20561 	}
20562 	error = rack_process_option(tp, rack, sopt->sopt_name, optval, loptval);
20563 	INP_WUNLOCK(inp);
20564 	return (error);
20565 }
20566 
20567 static void
20568 rack_fill_info(struct tcpcb *tp, struct tcp_info *ti)
20569 {
20570 
20571 	INP_WLOCK_ASSERT(tp->t_inpcb);
20572 	bzero(ti, sizeof(*ti));
20573 
20574 	ti->tcpi_state = tp->t_state;
20575 	if ((tp->t_flags & TF_REQ_TSTMP) && (tp->t_flags & TF_RCVD_TSTMP))
20576 		ti->tcpi_options |= TCPI_OPT_TIMESTAMPS;
20577 	if (tp->t_flags & TF_SACK_PERMIT)
20578 		ti->tcpi_options |= TCPI_OPT_SACK;
20579 	if ((tp->t_flags & TF_REQ_SCALE) && (tp->t_flags & TF_RCVD_SCALE)) {
20580 		ti->tcpi_options |= TCPI_OPT_WSCALE;
20581 		ti->tcpi_snd_wscale = tp->snd_scale;
20582 		ti->tcpi_rcv_wscale = tp->rcv_scale;
20583 	}
20584 	if (tp->t_flags2 & TF2_ECN_PERMIT)
20585 		ti->tcpi_options |= TCPI_OPT_ECN;
20586 	if (tp->t_flags & TF_FASTOPEN)
20587 		ti->tcpi_options |= TCPI_OPT_TFO;
20588 	/* still kept in ticks is t_rcvtime */
20589 	ti->tcpi_last_data_recv = ((uint32_t)ticks - tp->t_rcvtime) * tick;
20590 	/* Since we hold everything in precise useconds this is easy */
20591 	ti->tcpi_rtt = tp->t_srtt;
20592 	ti->tcpi_rttvar = tp->t_rttvar;
20593 	ti->tcpi_rto = tp->t_rxtcur;
20594 	ti->tcpi_snd_ssthresh = tp->snd_ssthresh;
20595 	ti->tcpi_snd_cwnd = tp->snd_cwnd;
20596 	/*
20597 	 * FreeBSD-specific extension fields for tcp_info.
20598 	 */
20599 	ti->tcpi_rcv_space = tp->rcv_wnd;
20600 	ti->tcpi_rcv_nxt = tp->rcv_nxt;
20601 	ti->tcpi_snd_wnd = tp->snd_wnd;
20602 	ti->tcpi_snd_bwnd = 0;		/* Unused, kept for compat. */
20603 	ti->tcpi_snd_nxt = tp->snd_nxt;
20604 	ti->tcpi_snd_mss = tp->t_maxseg;
20605 	ti->tcpi_rcv_mss = tp->t_maxseg;
20606 	ti->tcpi_snd_rexmitpack = tp->t_sndrexmitpack;
20607 	ti->tcpi_rcv_ooopack = tp->t_rcvoopack;
20608 	ti->tcpi_snd_zerowin = tp->t_sndzerowin;
20609 #ifdef NETFLIX_STATS
20610 	ti->tcpi_total_tlp = tp->t_sndtlppack;
20611 	ti->tcpi_total_tlp_bytes = tp->t_sndtlpbyte;
20612 	memcpy(&ti->tcpi_rxsyninfo, &tp->t_rxsyninfo, sizeof(struct tcpsyninfo));
20613 #endif
20614 #ifdef TCP_OFFLOAD
20615 	if (tp->t_flags & TF_TOE) {
20616 		ti->tcpi_options |= TCPI_OPT_TOE;
20617 		tcp_offload_tcp_info(tp, ti);
20618 	}
20619 #endif
20620 }
20621 
20622 static int
20623 rack_get_sockopt(struct socket *so, struct sockopt *sopt,
20624     struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack)
20625 {
20626 	int32_t error, optval;
20627 	uint64_t val, loptval;
20628 	struct	tcp_info ti;
20629 	/*
20630 	 * Because all our options are either boolean or an int, we can just
20631 	 * pull everything into optval and then unlock and copy. If we ever
20632 	 * add a option that is not a int, then this will have quite an
20633 	 * impact to this routine.
20634 	 */
20635 	error = 0;
20636 	switch (sopt->sopt_name) {
20637 	case TCP_INFO:
20638 		/* First get the info filled */
20639 		rack_fill_info(tp, &ti);
20640 		/* Fix up the rtt related fields if needed */
20641 		INP_WUNLOCK(inp);
20642 		error = sooptcopyout(sopt, &ti, sizeof ti);
20643 		return (error);
20644 	/*
20645 	 * Beta is the congestion control value for NewReno that influences how
20646 	 * much of a backoff happens when loss is detected. It is normally set
20647 	 * to 50 for 50% i.e. the cwnd is reduced to 50% of its previous value
20648 	 * when you exit recovery.
20649 	 */
20650 	case TCP_RACK_PACING_BETA:
20651 		if (strcmp(tp->cc_algo->name, CCALGONAME_NEWRENO) != 0)
20652 			error = EINVAL;
20653 		else if (rack->rc_pacing_cc_set == 0)
20654 			optval = rack->r_ctl.rc_saved_beta.beta;
20655 		else {
20656 			/*
20657 			 * Reach out into the CC data and report back what
20658 			 * I have previously set. Yeah it looks hackish but
20659 			 * we don't want to report the saved values.
20660 			 */
20661 			if (tp->ccv->cc_data)
20662 				optval = ((struct newreno *)tp->ccv->cc_data)->beta;
20663 			else
20664 				error = EINVAL;
20665 		}
20666 		break;
20667 		/*
20668 		 * Beta_ecn is the congestion control value for NewReno that influences how
20669 		 * much of a backoff happens when a ECN mark is detected. It is normally set
20670 		 * to 80 for 80% i.e. the cwnd is reduced by 20% of its previous value when
20671 		 * you exit recovery. Note that classic ECN has a beta of 50, it is only
20672 		 * ABE Ecn that uses this "less" value, but we do too with pacing :)
20673 		 */
20674 
20675 	case TCP_RACK_PACING_BETA_ECN:
20676 		if (strcmp(tp->cc_algo->name, CCALGONAME_NEWRENO) != 0)
20677 			error = EINVAL;
20678 		else if (rack->rc_pacing_cc_set == 0)
20679 			optval = rack->r_ctl.rc_saved_beta.beta_ecn;
20680 		else {
20681 			/*
20682 			 * Reach out into the CC data and report back what
20683 			 * I have previously set. Yeah it looks hackish but
20684 			 * we don't want to report the saved values.
20685 			 */
20686 			if (tp->ccv->cc_data)
20687 				optval = ((struct newreno *)tp->ccv->cc_data)->beta_ecn;
20688 			else
20689 				error = EINVAL;
20690 		}
20691 		break;
20692 	case TCP_RACK_DSACK_OPT:
20693 		optval = 0;
20694 		if (rack->rc_rack_tmr_std_based) {
20695 			optval |= 1;
20696 		}
20697 		if (rack->rc_rack_use_dsack) {
20698 			optval |= 2;
20699 		}
20700 		break;
20701  	case TCP_RACK_ENABLE_HYSTART:
20702 	{
20703 		struct sockopt sopt;
20704 		struct cc_newreno_opts opt;
20705 
20706 		sopt.sopt_valsize = sizeof(struct cc_newreno_opts);
20707 		sopt.sopt_dir = SOPT_GET;
20708 		opt.name = CC_NEWRENO_ENABLE_HYSTART;
20709 		if (CC_ALGO(tp)->ctl_output != NULL)
20710 			error = CC_ALGO(tp)->ctl_output(tp->ccv, &sopt, &opt);
20711 		else
20712 			error = EINVAL;
20713 		optval = opt.val;
20714 	}
20715 	break;
20716 	case TCP_FAST_RSM_HACK:
20717 		optval = rack->fast_rsm_hack;
20718 		break;
20719 	case TCP_DEFER_OPTIONS:
20720 		optval = rack->defer_options;
20721 		break;
20722 	case TCP_RACK_MEASURE_CNT:
20723 		optval = rack->r_ctl.req_measurements;
20724 		break;
20725 	case TCP_REC_ABC_VAL:
20726 		optval = rack->r_use_labc_for_rec;
20727 		break;
20728 	case TCP_RACK_ABC_VAL:
20729 		optval = rack->rc_labc;
20730 		break;
20731 	case TCP_HDWR_UP_ONLY:
20732 		optval= rack->r_up_only;
20733 		break;
20734 	case TCP_PACING_RATE_CAP:
20735 		loptval = rack->r_ctl.bw_rate_cap;
20736 		break;
20737 	case TCP_RACK_PROFILE:
20738 		/* You cannot retrieve a profile, its write only */
20739 		error = EINVAL;
20740 		break;
20741 	case TCP_USE_CMP_ACKS:
20742 		optval = rack->r_use_cmp_ack;
20743 		break;
20744 	case TCP_RACK_PACE_TO_FILL:
20745 		optval = rack->rc_pace_to_cwnd;
20746 		if (optval && rack->r_fill_less_agg)
20747 			optval++;
20748 		break;
20749 	case TCP_RACK_NO_PUSH_AT_MAX:
20750 		optval = rack->r_ctl.rc_no_push_at_mrtt;
20751 		break;
20752 	case TCP_SHARED_CWND_ENABLE:
20753 		optval = rack->rack_enable_scwnd;
20754 		break;
20755 	case TCP_RACK_NONRXT_CFG_RATE:
20756 		optval = rack->rack_rec_nonrxt_use_cr;
20757 		break;
20758 	case TCP_NO_PRR:
20759 		if (rack->rack_no_prr  == 1)
20760 			optval = 1;
20761 		else if (rack->no_prr_addback == 1)
20762 			optval = 2;
20763 		else
20764 			optval = 0;
20765 		break;
20766 	case TCP_RACK_DO_DETECTION:
20767 		optval = rack->do_detection;
20768 		break;
20769 	case TCP_RACK_MBUF_QUEUE:
20770 		/* Now do we use the LRO mbuf-queue feature */
20771 		optval = rack->r_mbuf_queue;
20772 		break;
20773 	case TCP_TIMELY_DYN_ADJ:
20774 		optval = rack->rc_gp_dyn_mul;
20775 		break;
20776 	case TCP_BBR_IWINTSO:
20777 		optval = rack->rc_init_win;
20778 		break;
20779 	case TCP_RACK_TLP_REDUCE:
20780 		/* RACK TLP cwnd reduction (bool) */
20781 		optval = rack->r_ctl.rc_tlp_cwnd_reduce;
20782 		break;
20783 	case TCP_BBR_RACK_INIT_RATE:
20784 		val = rack->r_ctl.init_rate;
20785 		/* convert to kbits per sec */
20786 		val *= 8;
20787 		val /= 1000;
20788 		optval = (uint32_t)val;
20789 		break;
20790 	case TCP_RACK_FORCE_MSEG:
20791 		optval = rack->rc_force_max_seg;
20792 		break;
20793 	case TCP_RACK_PACE_MAX_SEG:
20794 		/* Max segments in a pace */
20795 		optval = rack->rc_user_set_max_segs;
20796 		break;
20797 	case TCP_RACK_PACE_ALWAYS:
20798 		/* Use the always pace method */
20799 		optval = rack->rc_always_pace;
20800 		break;
20801 	case TCP_RACK_PRR_SENDALOT:
20802 		/* Allow PRR to send more than one seg */
20803 		optval = rack->r_ctl.rc_prr_sendalot;
20804 		break;
20805 	case TCP_RACK_MIN_TO:
20806 		/* Minimum time between rack t-o's in ms */
20807 		optval = rack->r_ctl.rc_min_to;
20808 		break;
20809 	case TCP_RACK_EARLY_SEG:
20810 		/* If early recovery max segments */
20811 		optval = rack->r_ctl.rc_early_recovery_segs;
20812 		break;
20813 	case TCP_RACK_REORD_THRESH:
20814 		/* RACK reorder threshold (shift amount) */
20815 		optval = rack->r_ctl.rc_reorder_shift;
20816 		break;
20817 	case TCP_RACK_REORD_FADE:
20818 		/* Does reordering fade after ms time */
20819 		optval = rack->r_ctl.rc_reorder_fade;
20820 		break;
20821 	case TCP_BBR_USE_RACK_RR:
20822 		/* Do we use the rack cheat for rxt */
20823 		optval = rack->use_rack_rr;
20824 		break;
20825 	case TCP_RACK_RR_CONF:
20826 		optval = rack->r_rr_config;
20827 		break;
20828 	case TCP_HDWR_RATE_CAP:
20829 		optval = rack->r_rack_hw_rate_caps;
20830 		break;
20831 	case TCP_BBR_HDWR_PACE:
20832 		optval = rack->rack_hdw_pace_ena;
20833 		break;
20834 	case TCP_RACK_TLP_THRESH:
20835 		/* RACK TLP theshold i.e. srtt+(srtt/N) */
20836 		optval = rack->r_ctl.rc_tlp_threshold;
20837 		break;
20838 	case TCP_RACK_PKT_DELAY:
20839 		/* RACK added ms i.e. rack-rtt + reord + N */
20840 		optval = rack->r_ctl.rc_pkt_delay;
20841 		break;
20842 	case TCP_RACK_TLP_USE:
20843 		optval = rack->rack_tlp_threshold_use;
20844 		break;
20845 	case TCP_RACK_PACE_RATE_CA:
20846 		optval = rack->r_ctl.rc_fixed_pacing_rate_ca;
20847 		break;
20848 	case TCP_RACK_PACE_RATE_SS:
20849 		optval = rack->r_ctl.rc_fixed_pacing_rate_ss;
20850 		break;
20851 	case TCP_RACK_PACE_RATE_REC:
20852 		optval = rack->r_ctl.rc_fixed_pacing_rate_rec;
20853 		break;
20854 	case TCP_RACK_GP_INCREASE_SS:
20855 		optval = rack->r_ctl.rack_per_of_gp_ca;
20856 		break;
20857 	case TCP_RACK_GP_INCREASE_CA:
20858 		optval = rack->r_ctl.rack_per_of_gp_ss;
20859 		break;
20860 	case TCP_BBR_RACK_RTT_USE:
20861 		optval = rack->r_ctl.rc_rate_sample_method;
20862 		break;
20863 	case TCP_DELACK:
20864 		optval = tp->t_delayed_ack;
20865 		break;
20866 	case TCP_DATA_AFTER_CLOSE:
20867 		optval = rack->rc_allow_data_af_clo;
20868 		break;
20869 	case TCP_SHARED_CWND_TIME_LIMIT:
20870 		optval = rack->r_limit_scw;
20871 		break;
20872 	case TCP_RACK_TIMER_SLOP:
20873 		optval = rack->r_ctl.timer_slop;
20874 		break;
20875 	default:
20876 		return (tcp_default_ctloutput(so, sopt, inp, tp));
20877 		break;
20878 	}
20879 	INP_WUNLOCK(inp);
20880 	if (error == 0) {
20881 		if (TCP_PACING_RATE_CAP)
20882 			error = sooptcopyout(sopt, &loptval, sizeof loptval);
20883 		else
20884 			error = sooptcopyout(sopt, &optval, sizeof optval);
20885 	}
20886 	return (error);
20887 }
20888 
20889 static int
20890 rack_ctloutput(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp)
20891 {
20892 	int32_t error = EINVAL;
20893 	struct tcp_rack *rack;
20894 
20895 	rack = (struct tcp_rack *)tp->t_fb_ptr;
20896 	if (rack == NULL) {
20897 		/* Huh? */
20898 		goto out;
20899 	}
20900 	if (sopt->sopt_dir == SOPT_SET) {
20901 		return (rack_set_sockopt(so, sopt, inp, tp, rack));
20902 	} else if (sopt->sopt_dir == SOPT_GET) {
20903 		return (rack_get_sockopt(so, sopt, inp, tp, rack));
20904 	}
20905 out:
20906 	INP_WUNLOCK(inp);
20907 	return (error);
20908 }
20909 
20910 static const char *rack_stack_names[] = {
20911 	__XSTRING(STACKNAME),
20912 #ifdef STACKALIAS
20913 	__XSTRING(STACKALIAS),
20914 #endif
20915 };
20916 
20917 static int
20918 rack_ctor(void *mem, int32_t size, void *arg, int32_t how)
20919 {
20920 	memset(mem, 0, size);
20921 	return (0);
20922 }
20923 
20924 static void
20925 rack_dtor(void *mem, int32_t size, void *arg)
20926 {
20927 
20928 }
20929 
20930 static bool rack_mod_inited = false;
20931 
20932 static int
20933 tcp_addrack(module_t mod, int32_t type, void *data)
20934 {
20935 	int32_t err = 0;
20936 	int num_stacks;
20937 
20938 	switch (type) {
20939 	case MOD_LOAD:
20940 		rack_zone = uma_zcreate(__XSTRING(MODNAME) "_map",
20941 		    sizeof(struct rack_sendmap),
20942 		    rack_ctor, rack_dtor, NULL, NULL, UMA_ALIGN_PTR, 0);
20943 
20944 		rack_pcb_zone = uma_zcreate(__XSTRING(MODNAME) "_pcb",
20945 		    sizeof(struct tcp_rack),
20946 		    rack_ctor, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
20947 
20948 		sysctl_ctx_init(&rack_sysctl_ctx);
20949 		rack_sysctl_root = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
20950 		    SYSCTL_STATIC_CHILDREN(_net_inet_tcp),
20951 		    OID_AUTO,
20952 #ifdef STACKALIAS
20953 		    __XSTRING(STACKALIAS),
20954 #else
20955 		    __XSTRING(STACKNAME),
20956 #endif
20957 		    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
20958 		    "");
20959 		if (rack_sysctl_root == NULL) {
20960 			printf("Failed to add sysctl node\n");
20961 			err = EFAULT;
20962 			goto free_uma;
20963 		}
20964 		rack_init_sysctls();
20965 		num_stacks = nitems(rack_stack_names);
20966 		err = register_tcp_functions_as_names(&__tcp_rack, M_WAITOK,
20967 		    rack_stack_names, &num_stacks);
20968 		if (err) {
20969 			printf("Failed to register %s stack name for "
20970 			    "%s module\n", rack_stack_names[num_stacks],
20971 			    __XSTRING(MODNAME));
20972 			sysctl_ctx_free(&rack_sysctl_ctx);
20973 free_uma:
20974 			uma_zdestroy(rack_zone);
20975 			uma_zdestroy(rack_pcb_zone);
20976 			rack_counter_destroy();
20977 			printf("Failed to register rack module -- err:%d\n", err);
20978 			return (err);
20979 		}
20980 		tcp_lro_reg_mbufq();
20981 		rack_mod_inited = true;
20982 		break;
20983 	case MOD_QUIESCE:
20984 		err = deregister_tcp_functions(&__tcp_rack, true, false);
20985 		break;
20986 	case MOD_UNLOAD:
20987 		err = deregister_tcp_functions(&__tcp_rack, false, true);
20988 		if (err == EBUSY)
20989 			break;
20990 		if (rack_mod_inited) {
20991 			uma_zdestroy(rack_zone);
20992 			uma_zdestroy(rack_pcb_zone);
20993 			sysctl_ctx_free(&rack_sysctl_ctx);
20994 			rack_counter_destroy();
20995 			rack_mod_inited = false;
20996 		}
20997 		tcp_lro_dereg_mbufq();
20998 		err = 0;
20999 		break;
21000 	default:
21001 		return (EOPNOTSUPP);
21002 	}
21003 	return (err);
21004 }
21005 
21006 static moduledata_t tcp_rack = {
21007 	.name = __XSTRING(MODNAME),
21008 	.evhand = tcp_addrack,
21009 	.priv = 0
21010 };
21011 
21012 MODULE_VERSION(MODNAME, 1);
21013 DECLARE_MODULE(MODNAME, tcp_rack, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
21014 MODULE_DEPEND(MODNAME, tcphpts, 1, 1, 1);
21015