xref: /freebsd/sys/netinet/tcp_stacks/rack.c (revision 4d3fc8b0570b29fb0d6ee9525f104d52176ff0d4) 
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_ratelimit.h"
34 #include "opt_kern_tls.h"
35 #if defined(INET) || defined(INET6)
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_syncache.h>
97 #include <netinet/tcp_hpts.h>
98 #include <netinet/tcp_ratelimit.h>
99 #include <netinet/tcp_accounting.h>
100 #include <netinet/tcpip.h>
101 #include <netinet/cc/cc.h>
102 #include <netinet/cc/cc_newreno.h>
103 #include <netinet/tcp_fastopen.h>
104 #include <netinet/tcp_lro.h>
105 #ifdef NETFLIX_SHARED_CWND
106 #include <netinet/tcp_shared_cwnd.h>
107 #endif
108 #ifdef TCP_OFFLOAD
109 #include <netinet/tcp_offload.h>
110 #endif
111 #ifdef INET6
112 #include <netinet6/tcp6_var.h>
113 #endif
114 #include <netinet/tcp_ecn.h>
115 
116 #include <netipsec/ipsec_support.h>
117 
118 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
119 #include <netipsec/ipsec.h>
120 #include <netipsec/ipsec6.h>
121 #endif				/* IPSEC */
122 
123 #include <netinet/udp.h>
124 #include <netinet/udp_var.h>
125 #include <machine/in_cksum.h>
126 
127 #ifdef MAC
128 #include <security/mac/mac_framework.h>
129 #endif
130 #include "sack_filter.h"
131 #include "tcp_rack.h"
132 #include "rack_bbr_common.h"
133 
134 uma_zone_t rack_zone;
135 uma_zone_t rack_pcb_zone;
136 
137 #ifndef TICKS2SBT
138 #define	TICKS2SBT(__t)	(tick_sbt * ((sbintime_t)(__t)))
139 #endif
140 
141 VNET_DECLARE(uint32_t, newreno_beta);
142 VNET_DECLARE(uint32_t, newreno_beta_ecn);
143 #define V_newreno_beta VNET(newreno_beta)
144 #define V_newreno_beta_ecn VNET(newreno_beta_ecn)
145 
146 
147 MALLOC_DEFINE(M_TCPFSB, "tcp_fsb", "TCP fast send block");
148 MALLOC_DEFINE(M_TCPDO, "tcp_do", "TCP deferred options");
149 
150 struct sysctl_ctx_list rack_sysctl_ctx;
151 struct sysctl_oid *rack_sysctl_root;
152 
153 #define CUM_ACKED 1
154 #define SACKED 2
155 
156 /*
157  * The RACK module incorporates a number of
158  * TCP ideas that have been put out into the IETF
159  * over the last few years:
160  * - Matt Mathis's Rate Halving which slowly drops
161  *    the congestion window so that the ack clock can
162  *    be maintained during a recovery.
163  * - Yuchung Cheng's RACK TCP (for which its named) that
164  *    will stop us using the number of dup acks and instead
165  *    use time as the gage of when we retransmit.
166  * - Reorder Detection of RFC4737 and the Tail-Loss probe draft
167  *    of Dukkipati et.al.
168  * RACK depends on SACK, so if an endpoint arrives that
169  * cannot do SACK the state machine below will shuttle the
170  * connection back to using the "default" TCP stack that is
171  * in FreeBSD.
172  *
173  * To implement RACK the original TCP stack was first decomposed
174  * into a functional state machine with individual states
175  * for each of the possible TCP connection states. The do_segment
176  * functions role in life is to mandate the connection supports SACK
177  * initially and then assure that the RACK state matches the conenction
178  * state before calling the states do_segment function. Each
179  * state is simplified due to the fact that the original do_segment
180  * has been decomposed and we *know* what state we are in (no
181  * switches on the state) and all tests for SACK are gone. This
182  * greatly simplifies what each state does.
183  *
184  * TCP output is also over-written with a new version since it
185  * must maintain the new rack scoreboard.
186  *
187  */
188 static int32_t rack_tlp_thresh = 1;
189 static int32_t rack_tlp_limit = 2;	/* No more than 2 TLPs w-out new data */
190 static int32_t rack_tlp_use_greater = 1;
191 static int32_t rack_reorder_thresh = 2;
192 static int32_t rack_reorder_fade = 60000000;	/* 0 - never fade, def 60,000,000
193 						 * - 60 seconds */
194 static uint8_t rack_req_measurements = 1;
195 /* Attack threshold detections */
196 static uint32_t rack_highest_sack_thresh_seen = 0;
197 static uint32_t rack_highest_move_thresh_seen = 0;
198 static int32_t rack_enable_hw_pacing = 0; /* Due to CCSP keep it off by default */
199 static int32_t rack_hw_pace_extra_slots = 2;	/* 2 extra MSS time betweens */
200 static int32_t rack_hw_rate_caps = 1; /* 1; */
201 static int32_t rack_hw_rate_min = 0; /* 1500000;*/
202 static int32_t rack_hw_rate_to_low = 0; /* 1200000; */
203 static int32_t rack_hw_up_only = 1;
204 static int32_t rack_stats_gets_ms_rtt = 1;
205 static int32_t rack_prr_addbackmax = 2;
206 static int32_t rack_do_hystart = 0;
207 static int32_t rack_apply_rtt_with_reduced_conf = 0;
208 
209 static int32_t rack_pkt_delay = 1000;
210 static int32_t rack_send_a_lot_in_prr = 1;
211 static int32_t rack_min_to = 1000;	/* Number of microsecond  min timeout */
212 static int32_t rack_verbose_logging = 0;
213 static int32_t rack_ignore_data_after_close = 1;
214 static int32_t rack_enable_shared_cwnd = 1;
215 static int32_t rack_use_cmp_acks = 1;
216 static int32_t rack_use_fsb = 1;
217 static int32_t rack_use_rfo = 1;
218 static int32_t rack_use_rsm_rfo = 1;
219 static int32_t rack_max_abc_post_recovery = 2;
220 static int32_t rack_client_low_buf = 0;
221 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 */
222 #ifdef TCP_ACCOUNTING
223 static int32_t rack_tcp_accounting = 0;
224 #endif
225 static int32_t rack_limits_scwnd = 1;
226 static int32_t rack_enable_mqueue_for_nonpaced = 0;
227 static int32_t rack_disable_prr = 0;
228 static int32_t use_rack_rr = 1;
229 static int32_t rack_non_rxt_use_cr = 0; /* does a non-rxt in recovery use the configured rate (ss/ca)? */
230 static int32_t rack_persist_min = 250000;	/* 250usec */
231 static int32_t rack_persist_max = 2000000;	/* 2 Second in usec's */
232 static int32_t rack_sack_not_required = 1;	/* set to one to allow non-sack to use rack */
233 static int32_t rack_default_init_window = 0;	/* Use system default */
234 static int32_t rack_limit_time_with_srtt = 0;
235 static int32_t rack_autosndbuf_inc = 20;	/* In percentage form */
236 static int32_t rack_enobuf_hw_boost_mult = 2;	/* How many times the hw rate we boost slot using time_between */
237 static int32_t rack_enobuf_hw_max = 12000;	/* 12 ms in usecs */
238 static int32_t rack_enobuf_hw_min = 10000;	/* 10 ms in usecs */
239 static int32_t rack_hw_rwnd_factor = 2;		/* How many max_segs the rwnd must be before we hold off sending */
240 
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 multiplier */
311 static int32_t rack_gp_increase_per = 2;	/* 2% increase in multiplier */
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 static uint32_t rack_trace_point_config = 0;
328 static uint32_t rack_trace_point_bb_mode = 4;
329 static int32_t rack_trace_point_count = 0;
330 
331 
332 /* Weird delayed ack mode */
333 static int32_t rack_use_imac_dack = 0;
334 /* Rack specific counters */
335 counter_u64_t rack_saw_enobuf;
336 counter_u64_t rack_saw_enobuf_hw;
337 counter_u64_t rack_saw_enetunreach;
338 counter_u64_t rack_persists_sends;
339 counter_u64_t rack_persists_acks;
340 counter_u64_t rack_persists_loss;
341 counter_u64_t rack_persists_lost_ends;
342 #ifdef INVARIANTS
343 counter_u64_t rack_adjust_map_bw;
344 #endif
345 /* Tail loss probe counters */
346 counter_u64_t rack_tlp_tot;
347 counter_u64_t rack_tlp_newdata;
348 counter_u64_t rack_tlp_retran;
349 counter_u64_t rack_tlp_retran_bytes;
350 counter_u64_t rack_to_tot;
351 counter_u64_t rack_hot_alloc;
352 counter_u64_t rack_to_alloc;
353 counter_u64_t rack_to_alloc_hard;
354 counter_u64_t rack_to_alloc_emerg;
355 counter_u64_t rack_to_alloc_limited;
356 counter_u64_t rack_alloc_limited_conns;
357 counter_u64_t rack_split_limited;
358 
359 counter_u64_t rack_multi_single_eq;
360 counter_u64_t rack_proc_non_comp_ack;
361 
362 counter_u64_t rack_fto_send;
363 counter_u64_t rack_fto_rsm_send;
364 counter_u64_t rack_nfto_resend;
365 counter_u64_t rack_non_fto_send;
366 counter_u64_t rack_extended_rfo;
367 
368 counter_u64_t rack_sack_proc_all;
369 counter_u64_t rack_sack_proc_short;
370 counter_u64_t rack_sack_proc_restart;
371 counter_u64_t rack_sack_attacks_detected;
372 counter_u64_t rack_sack_attacks_reversed;
373 counter_u64_t rack_sack_used_next_merge;
374 counter_u64_t rack_sack_splits;
375 counter_u64_t rack_sack_used_prev_merge;
376 counter_u64_t rack_sack_skipped_acked;
377 counter_u64_t rack_ack_total;
378 counter_u64_t rack_express_sack;
379 counter_u64_t rack_sack_total;
380 counter_u64_t rack_move_none;
381 counter_u64_t rack_move_some;
382 
383 counter_u64_t rack_input_idle_reduces;
384 counter_u64_t rack_collapsed_win;
385 counter_u64_t rack_collapsed_win_seen;
386 counter_u64_t rack_collapsed_win_rxt;
387 counter_u64_t rack_collapsed_win_rxt_bytes;
388 counter_u64_t rack_try_scwnd;
389 counter_u64_t rack_hw_pace_init_fail;
390 counter_u64_t rack_hw_pace_lost;
391 
392 counter_u64_t rack_out_size[TCP_MSS_ACCT_SIZE];
393 counter_u64_t rack_opts_arry[RACK_OPTS_SIZE];
394 
395 
396 #define	RACK_REXMTVAL(tp) max(rack_rto_min, ((tp)->t_srtt + ((tp)->t_rttvar << 2)))
397 
398 #define	RACK_TCPT_RANGESET(tv, value, tvmin, tvmax, slop) do {	\
399 	(tv) = (value) + slop;	 \
400 	if ((u_long)(tv) < (u_long)(tvmin)) \
401 		(tv) = (tvmin); \
402 	if ((u_long)(tv) > (u_long)(tvmax)) \
403 		(tv) = (tvmax); \
404 } while (0)
405 
406 static void
407 rack_log_progress_event(struct tcp_rack *rack, struct tcpcb *tp, uint32_t tick,  int event, int line);
408 
409 static int
410 rack_process_ack(struct mbuf *m, struct tcphdr *th,
411     struct socket *so, struct tcpcb *tp, struct tcpopt *to,
412     uint32_t tiwin, int32_t tlen, int32_t * ofia, int32_t thflags, int32_t * ret_val);
413 static int
414 rack_process_data(struct mbuf *m, struct tcphdr *th,
415     struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
416     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt);
417 static void
418 rack_ack_received(struct tcpcb *tp, struct tcp_rack *rack,
419    uint32_t th_ack, uint16_t nsegs, uint16_t type, int32_t recovery);
420 static struct rack_sendmap *rack_alloc(struct tcp_rack *rack);
421 static struct rack_sendmap *rack_alloc_limit(struct tcp_rack *rack,
422     uint8_t limit_type);
423 static struct rack_sendmap *
424 rack_check_recovery_mode(struct tcpcb *tp,
425     uint32_t tsused);
426 static void
427 rack_cong_signal(struct tcpcb *tp,
428 		 uint32_t type, uint32_t ack, int );
429 static void rack_counter_destroy(void);
430 static int
431 rack_ctloutput(struct inpcb *inp, struct sockopt *sopt);
432 static int32_t rack_ctor(void *mem, int32_t size, void *arg, int32_t how);
433 static void
434 rack_set_pace_segments(struct tcpcb *tp, struct tcp_rack *rack, uint32_t line, uint64_t *fill_override);
435 static void
436 rack_do_segment(struct mbuf *m, struct tcphdr *th,
437     struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
438     uint8_t iptos);
439 static void rack_dtor(void *mem, int32_t size, void *arg);
440 static void
441 rack_log_alt_to_to_cancel(struct tcp_rack *rack,
442     uint32_t flex1, uint32_t flex2,
443     uint32_t flex3, uint32_t flex4,
444     uint32_t flex5, uint32_t flex6,
445     uint16_t flex7, uint8_t mod);
446 
447 static void
448 rack_log_pacing_delay_calc(struct tcp_rack *rack, uint32_t len, uint32_t slot,
449    uint64_t bw_est, uint64_t bw, uint64_t len_time, int method, int line,
450    struct rack_sendmap *rsm, uint8_t quality);
451 static struct rack_sendmap *
452 rack_find_high_nonack(struct tcp_rack *rack,
453     struct rack_sendmap *rsm);
454 static struct rack_sendmap *rack_find_lowest_rsm(struct tcp_rack *rack);
455 static void rack_free(struct tcp_rack *rack, struct rack_sendmap *rsm);
456 static void rack_fini(struct tcpcb *tp, int32_t tcb_is_purged);
457 static int rack_get_sockopt(struct inpcb *inp, struct sockopt *sopt);
458 static void
459 rack_do_goodput_measurement(struct tcpcb *tp, struct tcp_rack *rack,
460 			    tcp_seq th_ack, int line, uint8_t quality);
461 static uint32_t
462 rack_get_pacing_len(struct tcp_rack *rack, uint64_t bw, uint32_t mss);
463 static int32_t rack_handoff_ok(struct tcpcb *tp);
464 static int32_t rack_init(struct tcpcb *tp);
465 static void rack_init_sysctls(void);
466 static void
467 rack_log_ack(struct tcpcb *tp, struct tcpopt *to,
468     struct tcphdr *th, int entered_rec, int dup_ack_struck);
469 static void
470 rack_log_output(struct tcpcb *tp, struct tcpopt *to, int32_t len,
471     uint32_t seq_out, uint16_t th_flags, int32_t err, uint64_t ts,
472     struct rack_sendmap *hintrsm, uint16_t add_flags, struct mbuf *s_mb, uint32_t s_moff, int hw_tls);
473 
474 static void
475 rack_log_sack_passed(struct tcpcb *tp, struct tcp_rack *rack,
476     struct rack_sendmap *rsm);
477 static void rack_log_to_event(struct tcp_rack *rack, int32_t to_num, struct rack_sendmap *rsm);
478 static int32_t rack_output(struct tcpcb *tp);
479 
480 static uint32_t
481 rack_proc_sack_blk(struct tcpcb *tp, struct tcp_rack *rack,
482     struct sackblk *sack, struct tcpopt *to, struct rack_sendmap **prsm,
483     uint32_t cts, int *moved_two);
484 static void rack_post_recovery(struct tcpcb *tp, uint32_t th_seq);
485 static void rack_remxt_tmr(struct tcpcb *tp);
486 static int rack_set_sockopt(struct inpcb *inp, struct sockopt *sopt);
487 static void rack_set_state(struct tcpcb *tp, struct tcp_rack *rack);
488 static int32_t rack_stopall(struct tcpcb *tp);
489 static void rack_timer_cancel(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int line);
490 static uint32_t
491 rack_update_entry(struct tcpcb *tp, struct tcp_rack *rack,
492     struct rack_sendmap *rsm, uint64_t ts, int32_t * lenp, uint16_t add_flag);
493 static void
494 rack_update_rsm(struct tcpcb *tp, struct tcp_rack *rack,
495     struct rack_sendmap *rsm, uint64_t ts, uint16_t add_flag);
496 static int
497 rack_update_rtt(struct tcpcb *tp, struct tcp_rack *rack,
498     struct rack_sendmap *rsm, struct tcpopt *to, uint32_t cts, int32_t ack_type, tcp_seq th_ack);
499 static int32_t tcp_addrack(module_t mod, int32_t type, void *data);
500 static int
501 rack_do_close_wait(struct mbuf *m, struct tcphdr *th,
502     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
503     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
504 static int
505 rack_do_closing(struct mbuf *m, struct tcphdr *th,
506     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
507     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
508 static int
509 rack_do_established(struct mbuf *m, struct tcphdr *th,
510     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
511     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
512 static int
513 rack_do_fastnewdata(struct mbuf *m, struct tcphdr *th,
514     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
515     int32_t tlen, uint32_t tiwin, int32_t nxt_pkt, uint8_t iptos);
516 static int
517 rack_do_fin_wait_1(struct mbuf *m, struct tcphdr *th,
518     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
519     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
520 static int
521 rack_do_fin_wait_2(struct mbuf *m, struct tcphdr *th,
522     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
523     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
524 static int
525 rack_do_lastack(struct mbuf *m, struct tcphdr *th,
526     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
527     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
528 static int
529 rack_do_syn_recv(struct mbuf *m, struct tcphdr *th,
530     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
531     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
532 static int
533 rack_do_syn_sent(struct mbuf *m, struct tcphdr *th,
534     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
535     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
536 struct rack_sendmap *
537 tcp_rack_output(struct tcpcb *tp, struct tcp_rack *rack,
538     uint32_t tsused);
539 static void tcp_rack_xmit_timer(struct tcp_rack *rack, int32_t rtt,
540     uint32_t len, uint32_t us_tim, int confidence, struct rack_sendmap *rsm, uint16_t rtrcnt);
541 static void
542      tcp_rack_partialack(struct tcpcb *tp);
543 static int
544 rack_set_profile(struct tcp_rack *rack, int prof);
545 static void
546 rack_apply_deferred_options(struct tcp_rack *rack);
547 
548 int32_t rack_clear_counter=0;
549 
550 static inline void
551 rack_trace_point(struct tcp_rack *rack, int num)
552 {
553 	if (((rack_trace_point_config == num)  ||
554 	     (rack_trace_point_config = 0xffffffff)) &&
555 	    (rack_trace_point_bb_mode != 0) &&
556 	    (rack_trace_point_count > 0) &&
557 	    (rack->rc_tp->t_logstate == 0)) {
558 		int res;
559 		res = atomic_fetchadd_int(&rack_trace_point_count, -1);
560 		if (res > 0) {
561 			rack->rc_tp->t_logstate = rack_trace_point_bb_mode;
562 		} else {
563 			/* Loss a race assure its zero now */
564 			rack_trace_point_count = 0;
565 		}
566 	}
567 }
568 
569 static void
570 rack_swap_beta_values(struct tcp_rack *rack, uint8_t flex8)
571 {
572 	struct sockopt sopt;
573 	struct cc_newreno_opts opt;
574 	struct newreno old;
575 	struct tcpcb *tp;
576 	int error, failed = 0;
577 
578 	tp = rack->rc_tp;
579 	if (tp->t_cc == NULL) {
580 		/* Tcb is leaving */
581 		return;
582 	}
583 	rack->rc_pacing_cc_set = 1;
584 	if (strcmp(tp->t_cc->name, CCALGONAME_NEWRENO) != 0) {
585 		/* Not new-reno we can't play games with beta! */
586 		failed = 1;
587 		goto out;
588 
589 	}
590 	if (CC_ALGO(tp)->ctl_output == NULL)  {
591 		/* Huh, not using new-reno so no swaps.? */
592 		failed = 2;
593 		goto out;
594 	}
595 	/* Get the current values out */
596 	sopt.sopt_valsize = sizeof(struct cc_newreno_opts);
597 	sopt.sopt_dir = SOPT_GET;
598 	opt.name = CC_NEWRENO_BETA;
599 	error = CC_ALGO(tp)->ctl_output(&tp->t_ccv, &sopt, &opt);
600 	if (error)  {
601 		failed = 3;
602 		goto out;
603 	}
604 	old.beta = opt.val;
605 	opt.name = CC_NEWRENO_BETA_ECN;
606 	error = CC_ALGO(tp)->ctl_output(&tp->t_ccv, &sopt, &opt);
607 	if (error)  {
608 		failed = 4;
609 		goto out;
610 	}
611 	old.beta_ecn = opt.val;
612 
613 	/* Now lets set in the values we have stored */
614 	sopt.sopt_dir = SOPT_SET;
615 	opt.name = CC_NEWRENO_BETA;
616 	opt.val = rack->r_ctl.rc_saved_beta.beta;
617 	error = CC_ALGO(tp)->ctl_output(&tp->t_ccv, &sopt, &opt);
618 	if (error)  {
619 		failed = 5;
620 		goto out;
621 	}
622 	opt.name = CC_NEWRENO_BETA_ECN;
623 	opt.val = rack->r_ctl.rc_saved_beta.beta_ecn;
624 	error = CC_ALGO(tp)->ctl_output(&tp->t_ccv, &sopt, &opt);
625 	if (error) {
626 		failed = 6;
627 		goto out;
628 	}
629 	/* Save off the values for restoral */
630 	memcpy(&rack->r_ctl.rc_saved_beta, &old, sizeof(struct newreno));
631 out:
632 	if (rack_verbose_logging && (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
633 		union tcp_log_stackspecific log;
634 		struct timeval tv;
635 		struct newreno *ptr;
636 
637 		ptr = ((struct newreno *)tp->t_ccv.cc_data);
638 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
639 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
640 		log.u_bbr.flex1 = ptr->beta;
641 		log.u_bbr.flex2 = ptr->beta_ecn;
642 		log.u_bbr.flex3 = ptr->newreno_flags;
643 		log.u_bbr.flex4 = rack->r_ctl.rc_saved_beta.beta;
644 		log.u_bbr.flex5 = rack->r_ctl.rc_saved_beta.beta_ecn;
645 		log.u_bbr.flex6 = failed;
646 		log.u_bbr.flex7 = rack->gp_ready;
647 		log.u_bbr.flex7 <<= 1;
648 		log.u_bbr.flex7 |= rack->use_fixed_rate;
649 		log.u_bbr.flex7 <<= 1;
650 		log.u_bbr.flex7 |= rack->rc_pacing_cc_set;
651 		log.u_bbr.pkts_out = rack->r_ctl.rc_prr_sndcnt;
652 		log.u_bbr.flex8 = flex8;
653 		tcp_log_event_(tp, NULL, NULL, NULL, BBR_LOG_CWND, error,
654 			       0, &log, false, NULL, NULL, 0, &tv);
655 	}
656 }
657 
658 static void
659 rack_set_cc_pacing(struct tcp_rack *rack)
660 {
661 	if (rack->rc_pacing_cc_set)
662 		return;
663 	/*
664 	 * Use the swap utility placing in 3 for flex8 to id a
665 	 * set of a new set of values.
666 	 */
667 	rack->rc_pacing_cc_set = 1;
668 	rack_swap_beta_values(rack, 3);
669 }
670 
671 static void
672 rack_undo_cc_pacing(struct tcp_rack *rack)
673 {
674 	if (rack->rc_pacing_cc_set == 0)
675 		return;
676 	/*
677 	 * Use the swap utility placing in 4 for flex8 to id a
678 	 * restoral of the old values.
679 	 */
680 	rack->rc_pacing_cc_set = 0;
681 	rack_swap_beta_values(rack, 4);
682 }
683 
684 #ifdef NETFLIX_PEAKRATE
685 static inline void
686 rack_update_peakrate_thr(struct tcpcb *tp)
687 {
688 	/* Keep in mind that t_maxpeakrate is in B/s. */
689 	uint64_t peak;
690 	peak = uqmax((tp->t_maxseg * 2),
691 		     (((uint64_t)tp->t_maxpeakrate * (uint64_t)(tp->t_srtt)) / (uint64_t)HPTS_USEC_IN_SEC));
692 	tp->t_peakrate_thr = (uint32_t)uqmin(peak, UINT32_MAX);
693 }
694 #endif
695 
696 static int
697 sysctl_rack_clear(SYSCTL_HANDLER_ARGS)
698 {
699 	uint32_t stat;
700 	int32_t error;
701 
702 	error = SYSCTL_OUT(req, &rack_clear_counter, sizeof(uint32_t));
703 	if (error || req->newptr == NULL)
704 		return error;
705 
706 	error = SYSCTL_IN(req, &stat, sizeof(uint32_t));
707 	if (error)
708 		return (error);
709 	if (stat == 1) {
710 #ifdef INVARIANTS
711 		printf("Clearing RACK counters\n");
712 #endif
713 		counter_u64_zero(rack_tlp_tot);
714 		counter_u64_zero(rack_tlp_newdata);
715 		counter_u64_zero(rack_tlp_retran);
716 		counter_u64_zero(rack_tlp_retran_bytes);
717 		counter_u64_zero(rack_to_tot);
718 		counter_u64_zero(rack_saw_enobuf);
719 		counter_u64_zero(rack_saw_enobuf_hw);
720 		counter_u64_zero(rack_saw_enetunreach);
721 		counter_u64_zero(rack_persists_sends);
722 		counter_u64_zero(rack_persists_acks);
723 		counter_u64_zero(rack_persists_loss);
724 		counter_u64_zero(rack_persists_lost_ends);
725 #ifdef INVARIANTS
726 		counter_u64_zero(rack_adjust_map_bw);
727 #endif
728 		counter_u64_zero(rack_to_alloc_hard);
729 		counter_u64_zero(rack_to_alloc_emerg);
730 		counter_u64_zero(rack_sack_proc_all);
731 		counter_u64_zero(rack_fto_send);
732 		counter_u64_zero(rack_fto_rsm_send);
733 		counter_u64_zero(rack_extended_rfo);
734 		counter_u64_zero(rack_hw_pace_init_fail);
735 		counter_u64_zero(rack_hw_pace_lost);
736 		counter_u64_zero(rack_non_fto_send);
737 		counter_u64_zero(rack_nfto_resend);
738 		counter_u64_zero(rack_sack_proc_short);
739 		counter_u64_zero(rack_sack_proc_restart);
740 		counter_u64_zero(rack_to_alloc);
741 		counter_u64_zero(rack_to_alloc_limited);
742 		counter_u64_zero(rack_alloc_limited_conns);
743 		counter_u64_zero(rack_split_limited);
744 		counter_u64_zero(rack_multi_single_eq);
745 		counter_u64_zero(rack_proc_non_comp_ack);
746 		counter_u64_zero(rack_sack_attacks_detected);
747 		counter_u64_zero(rack_sack_attacks_reversed);
748 		counter_u64_zero(rack_sack_used_next_merge);
749 		counter_u64_zero(rack_sack_used_prev_merge);
750 		counter_u64_zero(rack_sack_splits);
751 		counter_u64_zero(rack_sack_skipped_acked);
752 		counter_u64_zero(rack_ack_total);
753 		counter_u64_zero(rack_express_sack);
754 		counter_u64_zero(rack_sack_total);
755 		counter_u64_zero(rack_move_none);
756 		counter_u64_zero(rack_move_some);
757 		counter_u64_zero(rack_try_scwnd);
758 		counter_u64_zero(rack_collapsed_win);
759 		counter_u64_zero(rack_collapsed_win_rxt);
760 		counter_u64_zero(rack_collapsed_win_seen);
761 		counter_u64_zero(rack_collapsed_win_rxt_bytes);
762 	}
763 	rack_clear_counter = 0;
764 	return (0);
765 }
766 
767 static void
768 rack_init_sysctls(void)
769 {
770 	struct sysctl_oid *rack_counters;
771 	struct sysctl_oid *rack_attack;
772 	struct sysctl_oid *rack_pacing;
773 	struct sysctl_oid *rack_timely;
774 	struct sysctl_oid *rack_timers;
775 	struct sysctl_oid *rack_tlp;
776 	struct sysctl_oid *rack_misc;
777 	struct sysctl_oid *rack_features;
778 	struct sysctl_oid *rack_measure;
779 	struct sysctl_oid *rack_probertt;
780 	struct sysctl_oid *rack_hw_pacing;
781 	struct sysctl_oid *rack_tracepoint;
782 
783 	rack_attack = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
784 	    SYSCTL_CHILDREN(rack_sysctl_root),
785 	    OID_AUTO,
786 	    "sack_attack",
787 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
788 	    "Rack Sack Attack Counters and Controls");
789 	rack_counters = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
790 	    SYSCTL_CHILDREN(rack_sysctl_root),
791 	    OID_AUTO,
792 	    "stats",
793 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
794 	    "Rack Counters");
795 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
796 	    SYSCTL_CHILDREN(rack_sysctl_root),
797 	    OID_AUTO, "rate_sample_method", CTLFLAG_RW,
798 	    &rack_rate_sample_method , USE_RTT_LOW,
799 	    "What method should we use for rate sampling 0=high, 1=low ");
800 	/* Probe rtt related controls */
801 	rack_probertt = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
802 	    SYSCTL_CHILDREN(rack_sysctl_root),
803 	    OID_AUTO,
804 	    "probertt",
805 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
806 	    "ProbeRTT related Controls");
807 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
808 	    SYSCTL_CHILDREN(rack_probertt),
809 	    OID_AUTO, "exit_per_hpb", CTLFLAG_RW,
810 	    &rack_atexit_prtt_hbp, 130,
811 	    "What percentage above goodput do we clamp CA/SS to at exit on high-BDP path 110%");
812 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
813 	    SYSCTL_CHILDREN(rack_probertt),
814 	    OID_AUTO, "exit_per_nonhpb", CTLFLAG_RW,
815 	    &rack_atexit_prtt, 130,
816 	    "What percentage above goodput do we clamp CA/SS to at exit on a non high-BDP path 100%");
817 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
818 	    SYSCTL_CHILDREN(rack_probertt),
819 	    OID_AUTO, "gp_per_mul", CTLFLAG_RW,
820 	    &rack_per_of_gp_probertt, 60,
821 	    "What percentage of goodput do we pace at in probertt");
822 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
823 	    SYSCTL_CHILDREN(rack_probertt),
824 	    OID_AUTO, "gp_per_reduce", CTLFLAG_RW,
825 	    &rack_per_of_gp_probertt_reduce, 10,
826 	    "What percentage of goodput do we reduce every gp_srtt");
827 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
828 	    SYSCTL_CHILDREN(rack_probertt),
829 	    OID_AUTO, "gp_per_low", CTLFLAG_RW,
830 	    &rack_per_of_gp_lowthresh, 40,
831 	    "What percentage of goodput do we allow the multiplier to fall to");
832 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
833 	    SYSCTL_CHILDREN(rack_probertt),
834 	    OID_AUTO, "time_between", CTLFLAG_RW,
835 	    & rack_time_between_probertt, 96000000,
836 	    "How many useconds between the lowest rtt falling must past before we enter probertt");
837 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
838 	    SYSCTL_CHILDREN(rack_probertt),
839 	    OID_AUTO, "safety", CTLFLAG_RW,
840 	    &rack_probe_rtt_safety_val, 2000000,
841 	    "If not zero, provides a maximum usecond that you can stay in probertt (2sec = 2000000)");
842 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
843 	    SYSCTL_CHILDREN(rack_probertt),
844 	    OID_AUTO, "sets_cwnd", CTLFLAG_RW,
845 	    &rack_probe_rtt_sets_cwnd, 0,
846 	    "Do we set the cwnd too (if always_lower is on)");
847 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
848 	    SYSCTL_CHILDREN(rack_probertt),
849 	    OID_AUTO, "maxdrainsrtts", CTLFLAG_RW,
850 	    &rack_max_drain_wait, 2,
851 	    "Maximum number of gp_srtt's to hold in drain waiting for flight to reach goal");
852 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
853 	    SYSCTL_CHILDREN(rack_probertt),
854 	    OID_AUTO, "mustdrainsrtts", CTLFLAG_RW,
855 	    &rack_must_drain, 1,
856 	    "We must drain this many gp_srtt's waiting for flight to reach goal");
857 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
858 	    SYSCTL_CHILDREN(rack_probertt),
859 	    OID_AUTO, "goal_use_min_entry", CTLFLAG_RW,
860 	    &rack_probertt_use_min_rtt_entry, 1,
861 	    "Should we use the min-rtt to calculate the goal rtt (else gp_srtt) at entry");
862 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
863 	    SYSCTL_CHILDREN(rack_probertt),
864 	    OID_AUTO, "goal_use_min_exit", CTLFLAG_RW,
865 	    &rack_probertt_use_min_rtt_exit, 0,
866 	    "How to set cwnd at exit, 0 - dynamic, 1 - use min-rtt, 2 - use curgprtt, 3 - entry gp-rtt");
867 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
868 	    SYSCTL_CHILDREN(rack_probertt),
869 	    OID_AUTO, "length_div", CTLFLAG_RW,
870 	    &rack_probertt_gpsrtt_cnt_div, 0,
871 	    "How many recent goodput srtt periods plus hold tim does probertt last (bottom of fraction)");
872 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
873 	    SYSCTL_CHILDREN(rack_probertt),
874 	    OID_AUTO, "length_mul", CTLFLAG_RW,
875 	    &rack_probertt_gpsrtt_cnt_mul, 0,
876 	    "How many recent goodput srtt periods plus hold tim does probertt last (top of fraction)");
877 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
878 	    SYSCTL_CHILDREN(rack_probertt),
879 	    OID_AUTO, "holdtim_at_target", CTLFLAG_RW,
880 	    &rack_min_probertt_hold, 200000,
881 	    "What is the minimum time we hold probertt at target");
882 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
883 	    SYSCTL_CHILDREN(rack_probertt),
884 	    OID_AUTO, "filter_life", CTLFLAG_RW,
885 	    &rack_probertt_filter_life, 10000000,
886 	    "What is the time for the filters life in useconds");
887 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
888 	    SYSCTL_CHILDREN(rack_probertt),
889 	    OID_AUTO, "lower_within", CTLFLAG_RW,
890 	    &rack_probertt_lower_within, 10,
891 	    "If the rtt goes lower within this percentage of the time, go into probe-rtt");
892 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
893 	    SYSCTL_CHILDREN(rack_probertt),
894 	    OID_AUTO, "must_move", CTLFLAG_RW,
895 	    &rack_min_rtt_movement, 250,
896 	    "How much is the minimum movement in rtt to count as a drop for probertt purposes");
897 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
898 	    SYSCTL_CHILDREN(rack_probertt),
899 	    OID_AUTO, "clear_is_cnts", CTLFLAG_RW,
900 	    &rack_probertt_clear_is, 1,
901 	    "Do we clear I/S counts on exiting probe-rtt");
902 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
903 	    SYSCTL_CHILDREN(rack_probertt),
904 	    OID_AUTO, "hbp_extra_drain", CTLFLAG_RW,
905 	    &rack_max_drain_hbp, 1,
906 	    "How many extra drain gpsrtt's do we get in highly buffered paths");
907 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
908 	    SYSCTL_CHILDREN(rack_probertt),
909 	    OID_AUTO, "hbp_threshold", CTLFLAG_RW,
910 	    &rack_hbp_thresh, 3,
911 	    "We are highly buffered if min_rtt_seen / max_rtt_seen > this-threshold");
912 
913 	rack_tracepoint = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
914 	    SYSCTL_CHILDREN(rack_sysctl_root),
915 	    OID_AUTO,
916 	    "tp",
917 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
918 	    "Rack tracepoint facility");
919 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
920 	    SYSCTL_CHILDREN(rack_tracepoint),
921 	    OID_AUTO, "number", CTLFLAG_RW,
922 	    &rack_trace_point_config, 0,
923 	    "What is the trace point number to activate (0=none, 0xffffffff = all)?");
924 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
925 	    SYSCTL_CHILDREN(rack_tracepoint),
926 	    OID_AUTO, "bbmode", CTLFLAG_RW,
927 	    &rack_trace_point_bb_mode, 4,
928 	    "What is BB logging mode that is activated?");
929 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
930 	    SYSCTL_CHILDREN(rack_tracepoint),
931 	    OID_AUTO, "count", CTLFLAG_RW,
932 	    &rack_trace_point_count, 0,
933 	    "How many connections will have BB logging turned on that hit the tracepoint?");
934 	/* Pacing related sysctls */
935 	rack_pacing = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
936 	    SYSCTL_CHILDREN(rack_sysctl_root),
937 	    OID_AUTO,
938 	    "pacing",
939 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
940 	    "Pacing related Controls");
941 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
942 	    SYSCTL_CHILDREN(rack_pacing),
943 	    OID_AUTO, "max_pace_over", CTLFLAG_RW,
944 	    &rack_max_per_above, 30,
945 	    "What is the maximum allowable percentage that we can pace above (so 30 = 130% of our goal)");
946 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
947 	    SYSCTL_CHILDREN(rack_pacing),
948 	    OID_AUTO, "pace_to_one", CTLFLAG_RW,
949 	    &rack_pace_one_seg, 0,
950 	    "Do we allow low b/w pacing of 1MSS instead of two");
951 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
952 	    SYSCTL_CHILDREN(rack_pacing),
953 	    OID_AUTO, "limit_wsrtt", CTLFLAG_RW,
954 	    &rack_limit_time_with_srtt, 0,
955 	    "Do we limit pacing time based on srtt");
956 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
957 	    SYSCTL_CHILDREN(rack_pacing),
958 	    OID_AUTO, "init_win", CTLFLAG_RW,
959 	    &rack_default_init_window, 0,
960 	    "Do we have a rack initial window 0 = system default");
961 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
962 	    SYSCTL_CHILDREN(rack_pacing),
963 	    OID_AUTO, "gp_per_ss", CTLFLAG_RW,
964 	    &rack_per_of_gp_ss, 250,
965 	    "If non zero, what percentage of goodput to pace at in slow start");
966 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
967 	    SYSCTL_CHILDREN(rack_pacing),
968 	    OID_AUTO, "gp_per_ca", CTLFLAG_RW,
969 	    &rack_per_of_gp_ca, 150,
970 	    "If non zero, what percentage of goodput to pace at in congestion avoidance");
971 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
972 	    SYSCTL_CHILDREN(rack_pacing),
973 	    OID_AUTO, "gp_per_rec", CTLFLAG_RW,
974 	    &rack_per_of_gp_rec, 200,
975 	    "If non zero, what percentage of goodput to pace at in recovery");
976 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
977 	    SYSCTL_CHILDREN(rack_pacing),
978 	    OID_AUTO, "pace_max_seg", CTLFLAG_RW,
979 	    &rack_hptsi_segments, 40,
980 	    "What size is the max for TSO segments in pacing and burst mitigation");
981 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
982 	    SYSCTL_CHILDREN(rack_pacing),
983 	    OID_AUTO, "burst_reduces", CTLFLAG_RW,
984 	    &rack_slot_reduction, 4,
985 	    "When doing only burst mitigation what is the reduce divisor");
986 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
987 	    SYSCTL_CHILDREN(rack_sysctl_root),
988 	    OID_AUTO, "use_pacing", CTLFLAG_RW,
989 	    &rack_pace_every_seg, 0,
990 	    "If set we use pacing, if clear we use only the original burst mitigation");
991 	SYSCTL_ADD_U64(&rack_sysctl_ctx,
992 	    SYSCTL_CHILDREN(rack_pacing),
993 	    OID_AUTO, "rate_cap", CTLFLAG_RW,
994 	    &rack_bw_rate_cap, 0,
995 	    "If set we apply this value to the absolute rate cap used by pacing");
996 	SYSCTL_ADD_U8(&rack_sysctl_ctx,
997 	    SYSCTL_CHILDREN(rack_sysctl_root),
998 	    OID_AUTO, "req_measure_cnt", CTLFLAG_RW,
999 	    &rack_req_measurements, 1,
1000 	    "If doing dynamic pacing, how many measurements must be in before we start pacing?");
1001 	/* Hardware pacing */
1002 	rack_hw_pacing = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1003 	    SYSCTL_CHILDREN(rack_sysctl_root),
1004 	    OID_AUTO,
1005 	    "hdwr_pacing",
1006 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1007 	    "Pacing related Controls");
1008 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1009 	    SYSCTL_CHILDREN(rack_hw_pacing),
1010 	    OID_AUTO, "rwnd_factor", CTLFLAG_RW,
1011 	    &rack_hw_rwnd_factor, 2,
1012 	    "How many times does snd_wnd need to be bigger than pace_max_seg so we will hold off and get more acks?");
1013 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1014 	    SYSCTL_CHILDREN(rack_hw_pacing),
1015 	    OID_AUTO, "pace_enobuf_mult", CTLFLAG_RW,
1016 	    &rack_enobuf_hw_boost_mult, 2,
1017 	    "By how many time_betweens should we boost the pacing time if we see a ENOBUFS?");
1018 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1019 	    SYSCTL_CHILDREN(rack_hw_pacing),
1020 	    OID_AUTO, "pace_enobuf_max", CTLFLAG_RW,
1021 	    &rack_enobuf_hw_max, 2,
1022 	    "What is the max boost the pacing time if we see a ENOBUFS?");
1023 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1024 	    SYSCTL_CHILDREN(rack_hw_pacing),
1025 	    OID_AUTO, "pace_enobuf_min", CTLFLAG_RW,
1026 	    &rack_enobuf_hw_min, 2,
1027 	    "What is the min boost the pacing time if we see a ENOBUFS?");
1028 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1029 	    SYSCTL_CHILDREN(rack_hw_pacing),
1030 	    OID_AUTO, "enable", CTLFLAG_RW,
1031 	    &rack_enable_hw_pacing, 0,
1032 	    "Should RACK attempt to use hw pacing?");
1033 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1034 	    SYSCTL_CHILDREN(rack_hw_pacing),
1035 	    OID_AUTO, "rate_cap", CTLFLAG_RW,
1036 	    &rack_hw_rate_caps, 1,
1037 	    "Does the highest hardware pacing rate cap the rate we will send at??");
1038 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1039 	    SYSCTL_CHILDREN(rack_hw_pacing),
1040 	    OID_AUTO, "rate_min", CTLFLAG_RW,
1041 	    &rack_hw_rate_min, 0,
1042 	    "Do we need a minimum estimate of this many bytes per second in order to engage hw pacing?");
1043 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1044 	    SYSCTL_CHILDREN(rack_hw_pacing),
1045 	    OID_AUTO, "rate_to_low", CTLFLAG_RW,
1046 	    &rack_hw_rate_to_low, 0,
1047 	    "If we fall below this rate, dis-engage hw pacing?");
1048 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1049 	    SYSCTL_CHILDREN(rack_hw_pacing),
1050 	    OID_AUTO, "up_only", CTLFLAG_RW,
1051 	    &rack_hw_up_only, 1,
1052 	    "Do we allow hw pacing to lower the rate selected?");
1053 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1054 	    SYSCTL_CHILDREN(rack_hw_pacing),
1055 	    OID_AUTO, "extra_mss_precise", CTLFLAG_RW,
1056 	    &rack_hw_pace_extra_slots, 2,
1057 	    "If the rates between software and hardware match precisely how many extra time_betweens do we get?");
1058 	rack_timely = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1059 	    SYSCTL_CHILDREN(rack_sysctl_root),
1060 	    OID_AUTO,
1061 	    "timely",
1062 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1063 	    "Rack Timely RTT Controls");
1064 	/* Timely based GP dynmics */
1065 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1066 	    SYSCTL_CHILDREN(rack_timely),
1067 	    OID_AUTO, "upper", CTLFLAG_RW,
1068 	    &rack_gp_per_bw_mul_up, 2,
1069 	    "Rack timely upper range for equal b/w (in percentage)");
1070 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1071 	    SYSCTL_CHILDREN(rack_timely),
1072 	    OID_AUTO, "lower", CTLFLAG_RW,
1073 	    &rack_gp_per_bw_mul_down, 4,
1074 	    "Rack timely lower range for equal b/w (in percentage)");
1075 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1076 	    SYSCTL_CHILDREN(rack_timely),
1077 	    OID_AUTO, "rtt_max_mul", CTLFLAG_RW,
1078 	    &rack_gp_rtt_maxmul, 3,
1079 	    "Rack timely multiplier of lowest rtt for rtt_max");
1080 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1081 	    SYSCTL_CHILDREN(rack_timely),
1082 	    OID_AUTO, "rtt_min_div", CTLFLAG_RW,
1083 	    &rack_gp_rtt_mindiv, 4,
1084 	    "Rack timely divisor used for rtt + (rtt * mul/divisor) for check for lower rtt");
1085 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1086 	    SYSCTL_CHILDREN(rack_timely),
1087 	    OID_AUTO, "rtt_min_mul", CTLFLAG_RW,
1088 	    &rack_gp_rtt_minmul, 1,
1089 	    "Rack timely multiplier used for rtt + (rtt * mul/divisor) for check for lower rtt");
1090 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1091 	    SYSCTL_CHILDREN(rack_timely),
1092 	    OID_AUTO, "decrease", CTLFLAG_RW,
1093 	    &rack_gp_decrease_per, 20,
1094 	    "Rack timely decrease percentage of our GP multiplication factor");
1095 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1096 	    SYSCTL_CHILDREN(rack_timely),
1097 	    OID_AUTO, "increase", CTLFLAG_RW,
1098 	    &rack_gp_increase_per, 2,
1099 	    "Rack timely increase perentage of our GP multiplication factor");
1100 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1101 	    SYSCTL_CHILDREN(rack_timely),
1102 	    OID_AUTO, "lowerbound", CTLFLAG_RW,
1103 	    &rack_per_lower_bound, 50,
1104 	    "Rack timely lowest percentage we allow GP multiplier to fall to");
1105 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1106 	    SYSCTL_CHILDREN(rack_timely),
1107 	    OID_AUTO, "upperboundss", CTLFLAG_RW,
1108 	    &rack_per_upper_bound_ss, 0,
1109 	    "Rack timely highest percentage we allow GP multiplier in SS to raise to (0 is no upperbound)");
1110 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1111 	    SYSCTL_CHILDREN(rack_timely),
1112 	    OID_AUTO, "upperboundca", CTLFLAG_RW,
1113 	    &rack_per_upper_bound_ca, 0,
1114 	    "Rack timely highest percentage we allow GP multiplier to CA raise to (0 is no upperbound)");
1115 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1116 	    SYSCTL_CHILDREN(rack_timely),
1117 	    OID_AUTO, "dynamicgp", CTLFLAG_RW,
1118 	    &rack_do_dyn_mul, 0,
1119 	    "Rack timely do we enable dynmaic timely goodput by default");
1120 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1121 	    SYSCTL_CHILDREN(rack_timely),
1122 	    OID_AUTO, "no_rec_red", CTLFLAG_RW,
1123 	    &rack_gp_no_rec_chg, 1,
1124 	    "Rack timely do we prohibit the recovery multiplier from being lowered");
1125 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1126 	    SYSCTL_CHILDREN(rack_timely),
1127 	    OID_AUTO, "red_clear_cnt", CTLFLAG_RW,
1128 	    &rack_timely_dec_clear, 6,
1129 	    "Rack timely what threshold do we count to before another boost during b/w decent");
1130 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1131 	    SYSCTL_CHILDREN(rack_timely),
1132 	    OID_AUTO, "max_push_rise", CTLFLAG_RW,
1133 	    &rack_timely_max_push_rise, 3,
1134 	    "Rack timely how many times do we push up with b/w increase");
1135 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1136 	    SYSCTL_CHILDREN(rack_timely),
1137 	    OID_AUTO, "max_push_drop", CTLFLAG_RW,
1138 	    &rack_timely_max_push_drop, 3,
1139 	    "Rack timely how many times do we push back on b/w decent");
1140 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1141 	    SYSCTL_CHILDREN(rack_timely),
1142 	    OID_AUTO, "min_segs", CTLFLAG_RW,
1143 	    &rack_timely_min_segs, 4,
1144 	    "Rack timely when setting the cwnd what is the min num segments");
1145 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1146 	    SYSCTL_CHILDREN(rack_timely),
1147 	    OID_AUTO, "noback_max", CTLFLAG_RW,
1148 	    &rack_use_max_for_nobackoff, 0,
1149 	    "Rack timely when deciding if to backoff on a loss, do we use under max rtt else min");
1150 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1151 	    SYSCTL_CHILDREN(rack_timely),
1152 	    OID_AUTO, "interim_timely_only", CTLFLAG_RW,
1153 	    &rack_timely_int_timely_only, 0,
1154 	    "Rack timely when doing interim timely's do we only do timely (no b/w consideration)");
1155 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1156 	    SYSCTL_CHILDREN(rack_timely),
1157 	    OID_AUTO, "nonstop", CTLFLAG_RW,
1158 	    &rack_timely_no_stopping, 0,
1159 	    "Rack timely don't stop increase");
1160 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1161 	    SYSCTL_CHILDREN(rack_timely),
1162 	    OID_AUTO, "dec_raise_thresh", CTLFLAG_RW,
1163 	    &rack_down_raise_thresh, 100,
1164 	    "If the CA or SS is below this threshold raise on the first 3 b/w lowers (0=always)");
1165 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1166 	    SYSCTL_CHILDREN(rack_timely),
1167 	    OID_AUTO, "bottom_drag_segs", CTLFLAG_RW,
1168 	    &rack_req_segs, 1,
1169 	    "Bottom dragging if not these many segments outstanding and room");
1170 
1171 	/* TLP and Rack related parameters */
1172 	rack_tlp = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1173 	    SYSCTL_CHILDREN(rack_sysctl_root),
1174 	    OID_AUTO,
1175 	    "tlp",
1176 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1177 	    "TLP and Rack related Controls");
1178 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1179 	    SYSCTL_CHILDREN(rack_tlp),
1180 	    OID_AUTO, "use_rrr", CTLFLAG_RW,
1181 	    &use_rack_rr, 1,
1182 	    "Do we use Rack Rapid Recovery");
1183 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1184 	    SYSCTL_CHILDREN(rack_tlp),
1185 	    OID_AUTO, "post_rec_labc", CTLFLAG_RW,
1186 	    &rack_max_abc_post_recovery, 2,
1187 	    "Since we do early recovery, do we override the l_abc to a value, if so what?");
1188 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1189 	    SYSCTL_CHILDREN(rack_tlp),
1190 	    OID_AUTO, "nonrxt_use_cr", CTLFLAG_RW,
1191 	    &rack_non_rxt_use_cr, 0,
1192 	    "Do we use ss/ca rate if in recovery we are transmitting a new data chunk");
1193 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1194 	    SYSCTL_CHILDREN(rack_tlp),
1195 	    OID_AUTO, "tlpmethod", CTLFLAG_RW,
1196 	    &rack_tlp_threshold_use, TLP_USE_TWO_ONE,
1197 	    "What method do we do for TLP time calc 0=no-de-ack-comp, 1=ID, 2=2.1, 3=2.2");
1198 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1199 	    SYSCTL_CHILDREN(rack_tlp),
1200 	    OID_AUTO, "limit", CTLFLAG_RW,
1201 	    &rack_tlp_limit, 2,
1202 	    "How many TLP's can be sent without sending new data");
1203 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1204 	    SYSCTL_CHILDREN(rack_tlp),
1205 	    OID_AUTO, "use_greater", CTLFLAG_RW,
1206 	    &rack_tlp_use_greater, 1,
1207 	    "Should we use the rack_rtt time if its greater than srtt");
1208 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1209 	    SYSCTL_CHILDREN(rack_tlp),
1210 	    OID_AUTO, "tlpminto", CTLFLAG_RW,
1211 	    &rack_tlp_min, 10000,
1212 	    "TLP minimum timeout per the specification (in microseconds)");
1213 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1214 	    SYSCTL_CHILDREN(rack_tlp),
1215 	    OID_AUTO, "send_oldest", CTLFLAG_RW,
1216 	    &rack_always_send_oldest, 0,
1217 	    "Should we always send the oldest TLP and RACK-TLP");
1218 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1219 	    SYSCTL_CHILDREN(rack_tlp),
1220 	    OID_AUTO, "rack_tlimit", CTLFLAG_RW,
1221 	    &rack_limited_retran, 0,
1222 	    "How many times can a rack timeout drive out sends");
1223 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1224 	    SYSCTL_CHILDREN(rack_tlp),
1225 	    OID_AUTO, "tlp_cwnd_flag", CTLFLAG_RW,
1226 	    &rack_lower_cwnd_at_tlp, 0,
1227 	    "When a TLP completes a retran should we enter recovery");
1228 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1229 	    SYSCTL_CHILDREN(rack_tlp),
1230 	    OID_AUTO, "reorder_thresh", CTLFLAG_RW,
1231 	    &rack_reorder_thresh, 2,
1232 	    "What factor for rack will be added when seeing reordering (shift right)");
1233 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1234 	    SYSCTL_CHILDREN(rack_tlp),
1235 	    OID_AUTO, "rtt_tlp_thresh", CTLFLAG_RW,
1236 	    &rack_tlp_thresh, 1,
1237 	    "What divisor for TLP rtt/retran will be added (1=rtt, 2=1/2 rtt etc)");
1238 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1239 	    SYSCTL_CHILDREN(rack_tlp),
1240 	    OID_AUTO, "reorder_fade", CTLFLAG_RW,
1241 	    &rack_reorder_fade, 60000000,
1242 	    "Does reorder detection fade, if so how many microseconds (0 means never)");
1243 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1244 	    SYSCTL_CHILDREN(rack_tlp),
1245 	    OID_AUTO, "pktdelay", CTLFLAG_RW,
1246 	    &rack_pkt_delay, 1000,
1247 	    "Extra RACK time (in microseconds) besides reordering thresh");
1248 
1249 	/* Timer related controls */
1250 	rack_timers = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1251 	    SYSCTL_CHILDREN(rack_sysctl_root),
1252 	    OID_AUTO,
1253 	    "timers",
1254 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1255 	    "Timer related controls");
1256 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1257 	    SYSCTL_CHILDREN(rack_timers),
1258 	    OID_AUTO, "persmin", CTLFLAG_RW,
1259 	    &rack_persist_min, 250000,
1260 	    "What is the minimum time in microseconds between persists");
1261 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1262 	    SYSCTL_CHILDREN(rack_timers),
1263 	    OID_AUTO, "persmax", CTLFLAG_RW,
1264 	    &rack_persist_max, 2000000,
1265 	    "What is the largest delay in microseconds between persists");
1266 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1267 	    SYSCTL_CHILDREN(rack_timers),
1268 	    OID_AUTO, "delayed_ack", CTLFLAG_RW,
1269 	    &rack_delayed_ack_time, 40000,
1270 	    "Delayed ack time (40ms in microseconds)");
1271 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1272 	    SYSCTL_CHILDREN(rack_timers),
1273 	    OID_AUTO, "minrto", CTLFLAG_RW,
1274 	    &rack_rto_min, 30000,
1275 	    "Minimum RTO in microseconds -- set with caution below 1000 due to TLP");
1276 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1277 	    SYSCTL_CHILDREN(rack_timers),
1278 	    OID_AUTO, "maxrto", CTLFLAG_RW,
1279 	    &rack_rto_max, 4000000,
1280 	    "Maximum RTO in microseconds -- should be at least as large as min_rto");
1281 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1282 	    SYSCTL_CHILDREN(rack_timers),
1283 	    OID_AUTO, "minto", CTLFLAG_RW,
1284 	    &rack_min_to, 1000,
1285 	    "Minimum rack timeout in microseconds");
1286 	/* Measure controls */
1287 	rack_measure = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1288 	    SYSCTL_CHILDREN(rack_sysctl_root),
1289 	    OID_AUTO,
1290 	    "measure",
1291 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1292 	    "Measure related controls");
1293 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1294 	    SYSCTL_CHILDREN(rack_measure),
1295 	    OID_AUTO, "wma_divisor", CTLFLAG_RW,
1296 	    &rack_wma_divisor, 8,
1297 	    "When doing b/w calculation what is the  divisor for the WMA");
1298 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1299 	    SYSCTL_CHILDREN(rack_measure),
1300 	    OID_AUTO, "end_cwnd", CTLFLAG_RW,
1301 	    &rack_cwnd_block_ends_measure, 0,
1302 	    "Does a cwnd just-return end the measurement window (app limited)");
1303 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1304 	    SYSCTL_CHILDREN(rack_measure),
1305 	    OID_AUTO, "end_rwnd", CTLFLAG_RW,
1306 	    &rack_rwnd_block_ends_measure, 0,
1307 	    "Does an rwnd just-return end the measurement window (app limited -- not persists)");
1308 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1309 	    SYSCTL_CHILDREN(rack_measure),
1310 	    OID_AUTO, "min_target", CTLFLAG_RW,
1311 	    &rack_def_data_window, 20,
1312 	    "What is the minimum target window (in mss) for a GP measurements");
1313 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1314 	    SYSCTL_CHILDREN(rack_measure),
1315 	    OID_AUTO, "goal_bdp", CTLFLAG_RW,
1316 	    &rack_goal_bdp, 2,
1317 	    "What is the goal BDP to measure");
1318 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1319 	    SYSCTL_CHILDREN(rack_measure),
1320 	    OID_AUTO, "min_srtts", CTLFLAG_RW,
1321 	    &rack_min_srtts, 1,
1322 	    "What is the goal BDP to measure");
1323 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1324 	    SYSCTL_CHILDREN(rack_measure),
1325 	    OID_AUTO, "min_measure_tim", CTLFLAG_RW,
1326 	    &rack_min_measure_usec, 0,
1327 	    "What is the Minimum time time for a measurement if 0, this is off");
1328 	/* Features */
1329 	rack_features = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1330 	    SYSCTL_CHILDREN(rack_sysctl_root),
1331 	    OID_AUTO,
1332 	    "features",
1333 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1334 	    "Feature controls");
1335 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1336 	    SYSCTL_CHILDREN(rack_features),
1337 	    OID_AUTO, "cmpack", CTLFLAG_RW,
1338 	    &rack_use_cmp_acks, 1,
1339 	    "Should RACK have LRO send compressed acks");
1340 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1341 	    SYSCTL_CHILDREN(rack_features),
1342 	    OID_AUTO, "fsb", CTLFLAG_RW,
1343 	    &rack_use_fsb, 1,
1344 	    "Should RACK use the fast send block?");
1345 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1346 	    SYSCTL_CHILDREN(rack_features),
1347 	    OID_AUTO, "rfo", CTLFLAG_RW,
1348 	    &rack_use_rfo, 1,
1349 	    "Should RACK use rack_fast_output()?");
1350 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1351 	    SYSCTL_CHILDREN(rack_features),
1352 	    OID_AUTO, "rsmrfo", CTLFLAG_RW,
1353 	    &rack_use_rsm_rfo, 1,
1354 	    "Should RACK use rack_fast_rsm_output()?");
1355 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1356 	    SYSCTL_CHILDREN(rack_features),
1357 	    OID_AUTO, "non_paced_lro_queue", CTLFLAG_RW,
1358 	    &rack_enable_mqueue_for_nonpaced, 0,
1359 	    "Should RACK use mbuf queuing for non-paced connections");
1360 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1361 	    SYSCTL_CHILDREN(rack_features),
1362 	    OID_AUTO, "hystartplusplus", CTLFLAG_RW,
1363 	    &rack_do_hystart, 0,
1364 	    "Should RACK enable HyStart++ on connections?");
1365 	/* Misc rack controls */
1366 	rack_misc = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1367 	    SYSCTL_CHILDREN(rack_sysctl_root),
1368 	    OID_AUTO,
1369 	    "misc",
1370 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1371 	    "Misc related controls");
1372 #ifdef TCP_ACCOUNTING
1373 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1374 	    SYSCTL_CHILDREN(rack_misc),
1375 	    OID_AUTO, "tcp_acct", CTLFLAG_RW,
1376 	    &rack_tcp_accounting, 0,
1377 	    "Should we turn on TCP accounting for all rack sessions?");
1378 #endif
1379 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1380 	    SYSCTL_CHILDREN(rack_misc),
1381 	    OID_AUTO, "apply_rtt_with_low_conf", CTLFLAG_RW,
1382 	    &rack_apply_rtt_with_reduced_conf, 0,
1383 	    "When a persist or keep-alive probe is not answered do we calculate rtt on subsequent answers?");
1384 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1385 	    SYSCTL_CHILDREN(rack_misc),
1386 	    OID_AUTO, "rack_dsack_ctl", CTLFLAG_RW,
1387 	    &rack_dsack_std_based, 3,
1388 	    "How do we process dsack with respect to rack timers, bit field, 3 is standards based?");
1389 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1390 	    SYSCTL_CHILDREN(rack_misc),
1391 	    OID_AUTO, "prr_addback_max", CTLFLAG_RW,
1392 	    &rack_prr_addbackmax, 2,
1393 	    "What is the maximum number of MSS we allow to be added back if prr can't send all its data?");
1394 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1395 	    SYSCTL_CHILDREN(rack_misc),
1396 	    OID_AUTO, "stats_gets_ms", CTLFLAG_RW,
1397 	    &rack_stats_gets_ms_rtt, 1,
1398 	    "What do we feed the stats framework (1 = ms_rtt, 0 = us_rtt, 2 = ms_rtt from hdwr, > 2 usec rtt from hdwr)?");
1399 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1400 	    SYSCTL_CHILDREN(rack_misc),
1401 	    OID_AUTO, "clientlowbuf", CTLFLAG_RW,
1402 	    &rack_client_low_buf, 0,
1403 	    "Client low buffer level (below this we are more aggressive in DGP exiting recovery (0 = off)?");
1404 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1405 	    SYSCTL_CHILDREN(rack_misc),
1406 	    OID_AUTO, "defprofile", CTLFLAG_RW,
1407 	    &rack_def_profile, 0,
1408 	    "Should RACK use a default profile (0=no, num == profile num)?");
1409 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1410 	    SYSCTL_CHILDREN(rack_misc),
1411 	    OID_AUTO, "shared_cwnd", CTLFLAG_RW,
1412 	    &rack_enable_shared_cwnd, 1,
1413 	    "Should RACK try to use the shared cwnd on connections where allowed");
1414 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1415 	    SYSCTL_CHILDREN(rack_misc),
1416 	    OID_AUTO, "limits_on_scwnd", CTLFLAG_RW,
1417 	    &rack_limits_scwnd, 1,
1418 	    "Should RACK place low end time limits on the shared cwnd feature");
1419 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1420 	    SYSCTL_CHILDREN(rack_misc),
1421 	    OID_AUTO, "iMac_dack", CTLFLAG_RW,
1422 	    &rack_use_imac_dack, 0,
1423 	    "Should RACK try to emulate iMac delayed ack");
1424 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1425 	    SYSCTL_CHILDREN(rack_misc),
1426 	    OID_AUTO, "no_prr", CTLFLAG_RW,
1427 	    &rack_disable_prr, 0,
1428 	    "Should RACK not use prr and only pace (must have pacing on)");
1429 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1430 	    SYSCTL_CHILDREN(rack_misc),
1431 	    OID_AUTO, "bb_verbose", CTLFLAG_RW,
1432 	    &rack_verbose_logging, 0,
1433 	    "Should RACK black box logging be verbose");
1434 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1435 	    SYSCTL_CHILDREN(rack_misc),
1436 	    OID_AUTO, "data_after_close", CTLFLAG_RW,
1437 	    &rack_ignore_data_after_close, 1,
1438 	    "Do we hold off sending a RST until all pending data is ack'd");
1439 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1440 	    SYSCTL_CHILDREN(rack_misc),
1441 	    OID_AUTO, "no_sack_needed", CTLFLAG_RW,
1442 	    &rack_sack_not_required, 1,
1443 	    "Do we allow rack to run on connections not supporting SACK");
1444 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1445 	    SYSCTL_CHILDREN(rack_misc),
1446 	    OID_AUTO, "prr_sendalot", CTLFLAG_RW,
1447 	    &rack_send_a_lot_in_prr, 1,
1448 	    "Send a lot in prr");
1449 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1450 	    SYSCTL_CHILDREN(rack_misc),
1451 	    OID_AUTO, "autoscale", CTLFLAG_RW,
1452 	    &rack_autosndbuf_inc, 20,
1453 	    "What percentage should rack scale up its snd buffer by?");
1454 	/* Sack Attacker detection stuff */
1455 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1456 	    SYSCTL_CHILDREN(rack_attack),
1457 	    OID_AUTO, "detect_highsackratio", CTLFLAG_RW,
1458 	    &rack_highest_sack_thresh_seen, 0,
1459 	    "Highest sack to ack ratio seen");
1460 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1461 	    SYSCTL_CHILDREN(rack_attack),
1462 	    OID_AUTO, "detect_highmoveratio", CTLFLAG_RW,
1463 	    &rack_highest_move_thresh_seen, 0,
1464 	    "Highest move to non-move ratio seen");
1465 	rack_ack_total = counter_u64_alloc(M_WAITOK);
1466 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1467 	    SYSCTL_CHILDREN(rack_attack),
1468 	    OID_AUTO, "acktotal", CTLFLAG_RD,
1469 	    &rack_ack_total,
1470 	    "Total number of Ack's");
1471 	rack_express_sack = counter_u64_alloc(M_WAITOK);
1472 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1473 	    SYSCTL_CHILDREN(rack_attack),
1474 	    OID_AUTO, "exp_sacktotal", CTLFLAG_RD,
1475 	    &rack_express_sack,
1476 	    "Total expresss number of Sack's");
1477 	rack_sack_total = counter_u64_alloc(M_WAITOK);
1478 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1479 	    SYSCTL_CHILDREN(rack_attack),
1480 	    OID_AUTO, "sacktotal", CTLFLAG_RD,
1481 	    &rack_sack_total,
1482 	    "Total number of SACKs");
1483 	rack_move_none = counter_u64_alloc(M_WAITOK);
1484 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1485 	    SYSCTL_CHILDREN(rack_attack),
1486 	    OID_AUTO, "move_none", CTLFLAG_RD,
1487 	    &rack_move_none,
1488 	    "Total number of SACK index reuse of positions under threshold");
1489 	rack_move_some = counter_u64_alloc(M_WAITOK);
1490 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1491 	    SYSCTL_CHILDREN(rack_attack),
1492 	    OID_AUTO, "move_some", CTLFLAG_RD,
1493 	    &rack_move_some,
1494 	    "Total number of SACK index reuse of positions over threshold");
1495 	rack_sack_attacks_detected = counter_u64_alloc(M_WAITOK);
1496 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1497 	    SYSCTL_CHILDREN(rack_attack),
1498 	    OID_AUTO, "attacks", CTLFLAG_RD,
1499 	    &rack_sack_attacks_detected,
1500 	    "Total number of SACK attackers that had sack disabled");
1501 	rack_sack_attacks_reversed = counter_u64_alloc(M_WAITOK);
1502 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1503 	    SYSCTL_CHILDREN(rack_attack),
1504 	    OID_AUTO, "reversed", CTLFLAG_RD,
1505 	    &rack_sack_attacks_reversed,
1506 	    "Total number of SACK attackers that were later determined false positive");
1507 	rack_sack_used_next_merge = counter_u64_alloc(M_WAITOK);
1508 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1509 	    SYSCTL_CHILDREN(rack_attack),
1510 	    OID_AUTO, "nextmerge", CTLFLAG_RD,
1511 	    &rack_sack_used_next_merge,
1512 	    "Total number of times we used the next merge");
1513 	rack_sack_used_prev_merge = counter_u64_alloc(M_WAITOK);
1514 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1515 	    SYSCTL_CHILDREN(rack_attack),
1516 	    OID_AUTO, "prevmerge", CTLFLAG_RD,
1517 	    &rack_sack_used_prev_merge,
1518 	    "Total number of times we used the prev merge");
1519 	/* Counters */
1520 	rack_fto_send = counter_u64_alloc(M_WAITOK);
1521 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1522 	    SYSCTL_CHILDREN(rack_counters),
1523 	    OID_AUTO, "fto_send", CTLFLAG_RD,
1524 	    &rack_fto_send, "Total number of rack_fast_output sends");
1525 	rack_fto_rsm_send = counter_u64_alloc(M_WAITOK);
1526 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1527 	    SYSCTL_CHILDREN(rack_counters),
1528 	    OID_AUTO, "fto_rsm_send", CTLFLAG_RD,
1529 	    &rack_fto_rsm_send, "Total number of rack_fast_rsm_output sends");
1530 	rack_nfto_resend = counter_u64_alloc(M_WAITOK);
1531 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1532 	    SYSCTL_CHILDREN(rack_counters),
1533 	    OID_AUTO, "nfto_resend", CTLFLAG_RD,
1534 	    &rack_nfto_resend, "Total number of rack_output retransmissions");
1535 	rack_non_fto_send = counter_u64_alloc(M_WAITOK);
1536 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1537 	    SYSCTL_CHILDREN(rack_counters),
1538 	    OID_AUTO, "nfto_send", CTLFLAG_RD,
1539 	    &rack_non_fto_send, "Total number of rack_output first sends");
1540 	rack_extended_rfo = counter_u64_alloc(M_WAITOK);
1541 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1542 	    SYSCTL_CHILDREN(rack_counters),
1543 	    OID_AUTO, "rfo_extended", CTLFLAG_RD,
1544 	    &rack_extended_rfo, "Total number of times we extended rfo");
1545 
1546 	rack_hw_pace_init_fail = counter_u64_alloc(M_WAITOK);
1547 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1548 	    SYSCTL_CHILDREN(rack_counters),
1549 	    OID_AUTO, "hwpace_init_fail", CTLFLAG_RD,
1550 	    &rack_hw_pace_init_fail, "Total number of times we failed to initialize hw pacing");
1551 	rack_hw_pace_lost = counter_u64_alloc(M_WAITOK);
1552 
1553 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1554 	    SYSCTL_CHILDREN(rack_counters),
1555 	    OID_AUTO, "hwpace_lost", CTLFLAG_RD,
1556 	    &rack_hw_pace_lost, "Total number of times we failed to initialize hw pacing");
1557 	rack_tlp_tot = counter_u64_alloc(M_WAITOK);
1558 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1559 	    SYSCTL_CHILDREN(rack_counters),
1560 	    OID_AUTO, "tlp_to_total", CTLFLAG_RD,
1561 	    &rack_tlp_tot,
1562 	    "Total number of tail loss probe expirations");
1563 	rack_tlp_newdata = counter_u64_alloc(M_WAITOK);
1564 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1565 	    SYSCTL_CHILDREN(rack_counters),
1566 	    OID_AUTO, "tlp_new", CTLFLAG_RD,
1567 	    &rack_tlp_newdata,
1568 	    "Total number of tail loss probe sending new data");
1569 	rack_tlp_retran = counter_u64_alloc(M_WAITOK);
1570 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1571 	    SYSCTL_CHILDREN(rack_counters),
1572 	    OID_AUTO, "tlp_retran", CTLFLAG_RD,
1573 	    &rack_tlp_retran,
1574 	    "Total number of tail loss probe sending retransmitted data");
1575 	rack_tlp_retran_bytes = counter_u64_alloc(M_WAITOK);
1576 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1577 	    SYSCTL_CHILDREN(rack_counters),
1578 	    OID_AUTO, "tlp_retran_bytes", CTLFLAG_RD,
1579 	    &rack_tlp_retran_bytes,
1580 	    "Total bytes of tail loss probe sending retransmitted data");
1581 	rack_to_tot = counter_u64_alloc(M_WAITOK);
1582 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1583 	    SYSCTL_CHILDREN(rack_counters),
1584 	    OID_AUTO, "rack_to_tot", CTLFLAG_RD,
1585 	    &rack_to_tot,
1586 	    "Total number of times the rack to expired");
1587 	rack_saw_enobuf = counter_u64_alloc(M_WAITOK);
1588 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1589 	    SYSCTL_CHILDREN(rack_counters),
1590 	    OID_AUTO, "saw_enobufs", CTLFLAG_RD,
1591 	    &rack_saw_enobuf,
1592 	    "Total number of times a sends returned enobuf for non-hdwr paced connections");
1593 	rack_saw_enobuf_hw = counter_u64_alloc(M_WAITOK);
1594 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1595 	    SYSCTL_CHILDREN(rack_counters),
1596 	    OID_AUTO, "saw_enobufs_hw", CTLFLAG_RD,
1597 	    &rack_saw_enobuf_hw,
1598 	    "Total number of times a send returned enobuf for hdwr paced connections");
1599 	rack_saw_enetunreach = counter_u64_alloc(M_WAITOK);
1600 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1601 	    SYSCTL_CHILDREN(rack_counters),
1602 	    OID_AUTO, "saw_enetunreach", CTLFLAG_RD,
1603 	    &rack_saw_enetunreach,
1604 	    "Total number of times a send received a enetunreachable");
1605 	rack_hot_alloc = counter_u64_alloc(M_WAITOK);
1606 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1607 	    SYSCTL_CHILDREN(rack_counters),
1608 	    OID_AUTO, "alloc_hot", CTLFLAG_RD,
1609 	    &rack_hot_alloc,
1610 	    "Total allocations from the top of our list");
1611 	rack_to_alloc = counter_u64_alloc(M_WAITOK);
1612 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1613 	    SYSCTL_CHILDREN(rack_counters),
1614 	    OID_AUTO, "allocs", CTLFLAG_RD,
1615 	    &rack_to_alloc,
1616 	    "Total allocations of tracking structures");
1617 	rack_to_alloc_hard = counter_u64_alloc(M_WAITOK);
1618 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1619 	    SYSCTL_CHILDREN(rack_counters),
1620 	    OID_AUTO, "allochard", CTLFLAG_RD,
1621 	    &rack_to_alloc_hard,
1622 	    "Total allocations done with sleeping the hard way");
1623 	rack_to_alloc_emerg = counter_u64_alloc(M_WAITOK);
1624 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1625 	    SYSCTL_CHILDREN(rack_counters),
1626 	    OID_AUTO, "allocemerg", CTLFLAG_RD,
1627 	    &rack_to_alloc_emerg,
1628 	    "Total allocations done from emergency cache");
1629 	rack_to_alloc_limited = counter_u64_alloc(M_WAITOK);
1630 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1631 	    SYSCTL_CHILDREN(rack_counters),
1632 	    OID_AUTO, "alloc_limited", CTLFLAG_RD,
1633 	    &rack_to_alloc_limited,
1634 	    "Total allocations dropped due to limit");
1635 	rack_alloc_limited_conns = counter_u64_alloc(M_WAITOK);
1636 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1637 	    SYSCTL_CHILDREN(rack_counters),
1638 	    OID_AUTO, "alloc_limited_conns", CTLFLAG_RD,
1639 	    &rack_alloc_limited_conns,
1640 	    "Connections with allocations dropped due to limit");
1641 	rack_split_limited = counter_u64_alloc(M_WAITOK);
1642 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1643 	    SYSCTL_CHILDREN(rack_counters),
1644 	    OID_AUTO, "split_limited", CTLFLAG_RD,
1645 	    &rack_split_limited,
1646 	    "Split allocations dropped due to limit");
1647 	rack_persists_sends = counter_u64_alloc(M_WAITOK);
1648 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1649 	    SYSCTL_CHILDREN(rack_counters),
1650 	    OID_AUTO, "persist_sends", CTLFLAG_RD,
1651 	    &rack_persists_sends,
1652 	    "Number of times we sent a persist probe");
1653 	rack_persists_acks = counter_u64_alloc(M_WAITOK);
1654 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1655 	    SYSCTL_CHILDREN(rack_counters),
1656 	    OID_AUTO, "persist_acks", CTLFLAG_RD,
1657 	    &rack_persists_acks,
1658 	    "Number of times a persist probe was acked");
1659 	rack_persists_loss = counter_u64_alloc(M_WAITOK);
1660 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1661 	    SYSCTL_CHILDREN(rack_counters),
1662 	    OID_AUTO, "persist_loss", CTLFLAG_RD,
1663 	    &rack_persists_loss,
1664 	    "Number of times we detected a lost persist probe (no ack)");
1665 	rack_persists_lost_ends = counter_u64_alloc(M_WAITOK);
1666 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1667 	    SYSCTL_CHILDREN(rack_counters),
1668 	    OID_AUTO, "persist_loss_ends", CTLFLAG_RD,
1669 	    &rack_persists_lost_ends,
1670 	    "Number of lost persist probe (no ack) that the run ended with a PERSIST abort");
1671 #ifdef INVARIANTS
1672 	rack_adjust_map_bw = counter_u64_alloc(M_WAITOK);
1673 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1674 	    SYSCTL_CHILDREN(rack_counters),
1675 	    OID_AUTO, "map_adjust_req", CTLFLAG_RD,
1676 	    &rack_adjust_map_bw,
1677 	    "Number of times we hit the case where the sb went up and down on a sendmap entry");
1678 #endif
1679 	rack_multi_single_eq = counter_u64_alloc(M_WAITOK);
1680 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1681 	    SYSCTL_CHILDREN(rack_counters),
1682 	    OID_AUTO, "cmp_ack_equiv", CTLFLAG_RD,
1683 	    &rack_multi_single_eq,
1684 	    "Number of compressed acks total represented");
1685 	rack_proc_non_comp_ack = counter_u64_alloc(M_WAITOK);
1686 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1687 	    SYSCTL_CHILDREN(rack_counters),
1688 	    OID_AUTO, "cmp_ack_not", CTLFLAG_RD,
1689 	    &rack_proc_non_comp_ack,
1690 	    "Number of non compresseds acks that we processed");
1691 
1692 
1693 	rack_sack_proc_all = counter_u64_alloc(M_WAITOK);
1694 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1695 	    SYSCTL_CHILDREN(rack_counters),
1696 	    OID_AUTO, "sack_long", CTLFLAG_RD,
1697 	    &rack_sack_proc_all,
1698 	    "Total times we had to walk whole list for sack processing");
1699 	rack_sack_proc_restart = counter_u64_alloc(M_WAITOK);
1700 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1701 	    SYSCTL_CHILDREN(rack_counters),
1702 	    OID_AUTO, "sack_restart", CTLFLAG_RD,
1703 	    &rack_sack_proc_restart,
1704 	    "Total times we had to walk whole list due to a restart");
1705 	rack_sack_proc_short = counter_u64_alloc(M_WAITOK);
1706 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1707 	    SYSCTL_CHILDREN(rack_counters),
1708 	    OID_AUTO, "sack_short", CTLFLAG_RD,
1709 	    &rack_sack_proc_short,
1710 	    "Total times we took shortcut for sack processing");
1711 	rack_sack_skipped_acked = counter_u64_alloc(M_WAITOK);
1712 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1713 	    SYSCTL_CHILDREN(rack_attack),
1714 	    OID_AUTO, "skipacked", CTLFLAG_RD,
1715 	    &rack_sack_skipped_acked,
1716 	    "Total number of times we skipped previously sacked");
1717 	rack_sack_splits = counter_u64_alloc(M_WAITOK);
1718 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1719 	    SYSCTL_CHILDREN(rack_attack),
1720 	    OID_AUTO, "ofsplit", CTLFLAG_RD,
1721 	    &rack_sack_splits,
1722 	    "Total number of times we did the old fashion tree split");
1723 	rack_input_idle_reduces = counter_u64_alloc(M_WAITOK);
1724 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1725 	    SYSCTL_CHILDREN(rack_counters),
1726 	    OID_AUTO, "idle_reduce_oninput", CTLFLAG_RD,
1727 	    &rack_input_idle_reduces,
1728 	    "Total number of idle reductions on input");
1729 	rack_collapsed_win_seen = counter_u64_alloc(M_WAITOK);
1730 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1731 	    SYSCTL_CHILDREN(rack_counters),
1732 	    OID_AUTO, "collapsed_win_seen", CTLFLAG_RD,
1733 	    &rack_collapsed_win_seen,
1734 	    "Total number of collapsed window events seen (where our window shrinks)");
1735 
1736 	rack_collapsed_win = counter_u64_alloc(M_WAITOK);
1737 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1738 	    SYSCTL_CHILDREN(rack_counters),
1739 	    OID_AUTO, "collapsed_win", CTLFLAG_RD,
1740 	    &rack_collapsed_win,
1741 	    "Total number of collapsed window events where we mark packets");
1742 	rack_collapsed_win_rxt = counter_u64_alloc(M_WAITOK);
1743 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1744 	    SYSCTL_CHILDREN(rack_counters),
1745 	    OID_AUTO, "collapsed_win_rxt", CTLFLAG_RD,
1746 	    &rack_collapsed_win_rxt,
1747 	    "Total number of packets that were retransmitted");
1748 	rack_collapsed_win_rxt_bytes = counter_u64_alloc(M_WAITOK);
1749 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1750 	    SYSCTL_CHILDREN(rack_counters),
1751 	    OID_AUTO, "collapsed_win_bytes", CTLFLAG_RD,
1752 	    &rack_collapsed_win_rxt_bytes,
1753 	    "Total number of bytes that were retransmitted");
1754 	rack_try_scwnd = counter_u64_alloc(M_WAITOK);
1755 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1756 	    SYSCTL_CHILDREN(rack_counters),
1757 	    OID_AUTO, "tried_scwnd", CTLFLAG_RD,
1758 	    &rack_try_scwnd,
1759 	    "Total number of scwnd attempts");
1760 	COUNTER_ARRAY_ALLOC(rack_out_size, TCP_MSS_ACCT_SIZE, M_WAITOK);
1761 	SYSCTL_ADD_COUNTER_U64_ARRAY(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root),
1762 	    OID_AUTO, "outsize", CTLFLAG_RD,
1763 	    rack_out_size, TCP_MSS_ACCT_SIZE, "MSS send sizes");
1764 	COUNTER_ARRAY_ALLOC(rack_opts_arry, RACK_OPTS_SIZE, M_WAITOK);
1765 	SYSCTL_ADD_COUNTER_U64_ARRAY(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root),
1766 	    OID_AUTO, "opts", CTLFLAG_RD,
1767 	    rack_opts_arry, RACK_OPTS_SIZE, "RACK Option Stats");
1768 	SYSCTL_ADD_PROC(&rack_sysctl_ctx,
1769 	    SYSCTL_CHILDREN(rack_sysctl_root),
1770 	    OID_AUTO, "clear", CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE,
1771 	    &rack_clear_counter, 0, sysctl_rack_clear, "IU", "Clear counters");
1772 }
1773 
1774 static __inline int
1775 rb_map_cmp(struct rack_sendmap *b, struct rack_sendmap *a)
1776 {
1777 	if (SEQ_GEQ(b->r_start, a->r_start) &&
1778 	    SEQ_LT(b->r_start, a->r_end)) {
1779 		/*
1780 		 * The entry b is within the
1781 		 * block a. i.e.:
1782 		 * a --   |-------------|
1783 		 * b --   |----|
1784 		 * <or>
1785 		 * b --       |------|
1786 		 * <or>
1787 		 * b --       |-----------|
1788 		 */
1789 		return (0);
1790 	} else if (SEQ_GEQ(b->r_start, a->r_end)) {
1791 		/*
1792 		 * b falls as either the next
1793 		 * sequence block after a so a
1794 		 * is said to be smaller than b.
1795 		 * i.e:
1796 		 * a --   |------|
1797 		 * b --          |--------|
1798 		 * or
1799 		 * b --              |-----|
1800 		 */
1801 		return (1);
1802 	}
1803 	/*
1804 	 * Whats left is where a is
1805 	 * larger than b. i.e:
1806 	 * a --         |-------|
1807 	 * b --  |---|
1808 	 * or even possibly
1809 	 * b --   |--------------|
1810 	 */
1811 	return (-1);
1812 }
1813 
1814 RB_PROTOTYPE(rack_rb_tree_head, rack_sendmap, r_next, rb_map_cmp);
1815 RB_GENERATE(rack_rb_tree_head, rack_sendmap, r_next, rb_map_cmp);
1816 
1817 static uint32_t
1818 rc_init_window(struct tcp_rack *rack)
1819 {
1820 	uint32_t win;
1821 
1822 	if (rack->rc_init_win == 0) {
1823 		/*
1824 		 * Nothing set by the user, use the system stack
1825 		 * default.
1826 		 */
1827 		return (tcp_compute_initwnd(tcp_maxseg(rack->rc_tp)));
1828 	}
1829 	win = ctf_fixed_maxseg(rack->rc_tp) * rack->rc_init_win;
1830 	return (win);
1831 }
1832 
1833 static uint64_t
1834 rack_get_fixed_pacing_bw(struct tcp_rack *rack)
1835 {
1836 	if (IN_FASTRECOVERY(rack->rc_tp->t_flags))
1837 		return (rack->r_ctl.rc_fixed_pacing_rate_rec);
1838 	else if (rack->r_ctl.cwnd_to_use < rack->rc_tp->snd_ssthresh)
1839 		return (rack->r_ctl.rc_fixed_pacing_rate_ss);
1840 	else
1841 		return (rack->r_ctl.rc_fixed_pacing_rate_ca);
1842 }
1843 
1844 static uint64_t
1845 rack_get_bw(struct tcp_rack *rack)
1846 {
1847 	if (rack->use_fixed_rate) {
1848 		/* Return the fixed pacing rate */
1849 		return (rack_get_fixed_pacing_bw(rack));
1850 	}
1851 	if (rack->r_ctl.gp_bw == 0) {
1852 		/*
1853 		 * We have yet no b/w measurement,
1854 		 * if we have a user set initial bw
1855 		 * return it. If we don't have that and
1856 		 * we have an srtt, use the tcp IW (10) to
1857 		 * calculate a fictional b/w over the SRTT
1858 		 * which is more or less a guess. Note
1859 		 * we don't use our IW from rack on purpose
1860 		 * so if we have like IW=30, we are not
1861 		 * calculating a "huge" b/w.
1862 		 */
1863 		uint64_t bw, srtt;
1864 		if (rack->r_ctl.init_rate)
1865 			return (rack->r_ctl.init_rate);
1866 
1867 		/* Has the user set a max peak rate? */
1868 #ifdef NETFLIX_PEAKRATE
1869 		if (rack->rc_tp->t_maxpeakrate)
1870 			return (rack->rc_tp->t_maxpeakrate);
1871 #endif
1872 		/* Ok lets come up with the IW guess, if we have a srtt */
1873 		if (rack->rc_tp->t_srtt == 0) {
1874 			/*
1875 			 * Go with old pacing method
1876 			 * i.e. burst mitigation only.
1877 			 */
1878 			return (0);
1879 		}
1880 		/* Ok lets get the initial TCP win (not racks) */
1881 		bw = tcp_compute_initwnd(tcp_maxseg(rack->rc_tp));
1882 		srtt = (uint64_t)rack->rc_tp->t_srtt;
1883 		bw *= (uint64_t)USECS_IN_SECOND;
1884 		bw /= srtt;
1885 		if (rack->r_ctl.bw_rate_cap && (bw > rack->r_ctl.bw_rate_cap))
1886 			bw = rack->r_ctl.bw_rate_cap;
1887 		return (bw);
1888 	} else {
1889 		uint64_t bw;
1890 
1891 		if (rack->r_ctl.num_measurements >= RACK_REQ_AVG) {
1892 			/* Averaging is done, we can return the value */
1893 			bw = rack->r_ctl.gp_bw;
1894 		} else {
1895 			/* Still doing initial average must calculate */
1896 			bw = rack->r_ctl.gp_bw / rack->r_ctl.num_measurements;
1897 		}
1898 #ifdef NETFLIX_PEAKRATE
1899 		if ((rack->rc_tp->t_maxpeakrate) &&
1900 		    (bw > rack->rc_tp->t_maxpeakrate)) {
1901 			/* The user has set a peak rate to pace at
1902 			 * don't allow us to pace faster than that.
1903 			 */
1904 			return (rack->rc_tp->t_maxpeakrate);
1905 		}
1906 #endif
1907 		if (rack->r_ctl.bw_rate_cap && (bw > rack->r_ctl.bw_rate_cap))
1908 			bw = rack->r_ctl.bw_rate_cap;
1909 		return (bw);
1910 	}
1911 }
1912 
1913 static uint16_t
1914 rack_get_output_gain(struct tcp_rack *rack, struct rack_sendmap *rsm)
1915 {
1916 	if (rack->use_fixed_rate) {
1917 		return (100);
1918 	} else if (rack->in_probe_rtt && (rsm == NULL))
1919 		return (rack->r_ctl.rack_per_of_gp_probertt);
1920 	else if ((IN_FASTRECOVERY(rack->rc_tp->t_flags) &&
1921 		  rack->r_ctl.rack_per_of_gp_rec)) {
1922 		if (rsm) {
1923 			/* a retransmission always use the recovery rate */
1924 			return (rack->r_ctl.rack_per_of_gp_rec);
1925 		} else if (rack->rack_rec_nonrxt_use_cr) {
1926 			/* Directed to use the configured rate */
1927 			goto configured_rate;
1928 		} else if (rack->rack_no_prr &&
1929 			   (rack->r_ctl.rack_per_of_gp_rec > 100)) {
1930 			/* No PRR, lets just use the b/w estimate only */
1931 			return (100);
1932 		} else {
1933 			/*
1934 			 * Here we may have a non-retransmit but we
1935 			 * have no overrides, so just use the recovery
1936 			 * rate (prr is in effect).
1937 			 */
1938 			return (rack->r_ctl.rack_per_of_gp_rec);
1939 		}
1940 	}
1941 configured_rate:
1942 	/* For the configured rate we look at our cwnd vs the ssthresh */
1943 	if (rack->r_ctl.cwnd_to_use < rack->rc_tp->snd_ssthresh)
1944 		return (rack->r_ctl.rack_per_of_gp_ss);
1945 	else
1946 		return (rack->r_ctl.rack_per_of_gp_ca);
1947 }
1948 
1949 static void
1950 rack_log_dsack_event(struct tcp_rack *rack, uint8_t mod, uint32_t flex4, uint32_t flex5, uint32_t flex6)
1951 {
1952 	/*
1953 	 * Types of logs (mod value)
1954 	 * 1 = dsack_persists reduced by 1 via T-O or fast recovery exit.
1955 	 * 2 = a dsack round begins, persist is reset to 16.
1956 	 * 3 = a dsack round ends
1957 	 * 4 = Dsack option increases rack rtt flex5 is the srtt input, flex6 is thresh
1958 	 * 5 = Socket option set changing the control flags rc_rack_tmr_std_based, rc_rack_use_dsack
1959 	 * 6 = Final rack rtt, flex4 is srtt and flex6 is final limited thresh.
1960 	 */
1961 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1962 		union tcp_log_stackspecific log;
1963 		struct timeval tv;
1964 
1965 		memset(&log, 0, sizeof(log));
1966 		log.u_bbr.flex1 = rack->rc_rack_tmr_std_based;
1967 		log.u_bbr.flex1 <<= 1;
1968 		log.u_bbr.flex1 |= rack->rc_rack_use_dsack;
1969 		log.u_bbr.flex1 <<= 1;
1970 		log.u_bbr.flex1 |= rack->rc_dsack_round_seen;
1971 		log.u_bbr.flex2 = rack->r_ctl.dsack_round_end;
1972 		log.u_bbr.flex3 = rack->r_ctl.num_dsack;
1973 		log.u_bbr.flex4 = flex4;
1974 		log.u_bbr.flex5 = flex5;
1975 		log.u_bbr.flex6 = flex6;
1976 		log.u_bbr.flex7 = rack->r_ctl.dsack_persist;
1977 		log.u_bbr.flex8 = mod;
1978 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1979 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1980 		    &rack->rc_inp->inp_socket->so_rcv,
1981 		    &rack->rc_inp->inp_socket->so_snd,
1982 		    RACK_DSACK_HANDLING, 0,
1983 		    0, &log, false, &tv);
1984 	}
1985 }
1986 
1987 static void
1988 rack_log_hdwr_pacing(struct tcp_rack *rack,
1989 		     uint64_t rate, uint64_t hw_rate, int line,
1990 		     int error, uint16_t mod)
1991 {
1992 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1993 		union tcp_log_stackspecific log;
1994 		struct timeval tv;
1995 		const struct ifnet *ifp;
1996 
1997 		memset(&log, 0, sizeof(log));
1998 		log.u_bbr.flex1 = ((hw_rate >> 32) & 0x00000000ffffffff);
1999 		log.u_bbr.flex2 = (hw_rate & 0x00000000ffffffff);
2000 		if (rack->r_ctl.crte) {
2001 			ifp = rack->r_ctl.crte->ptbl->rs_ifp;
2002 		} else if (rack->rc_inp->inp_route.ro_nh &&
2003 			   rack->rc_inp->inp_route.ro_nh->nh_ifp) {
2004 			ifp = rack->rc_inp->inp_route.ro_nh->nh_ifp;
2005 		} else
2006 			ifp = NULL;
2007 		if (ifp) {
2008 			log.u_bbr.flex3 = (((uint64_t)ifp  >> 32) & 0x00000000ffffffff);
2009 			log.u_bbr.flex4 = ((uint64_t)ifp & 0x00000000ffffffff);
2010 		}
2011 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2012 		log.u_bbr.bw_inuse = rate;
2013 		log.u_bbr.flex5 = line;
2014 		log.u_bbr.flex6 = error;
2015 		log.u_bbr.flex7 = mod;
2016 		log.u_bbr.applimited = rack->r_ctl.rc_pace_max_segs;
2017 		log.u_bbr.flex8 = rack->use_fixed_rate;
2018 		log.u_bbr.flex8 <<= 1;
2019 		log.u_bbr.flex8 |= rack->rack_hdrw_pacing;
2020 		log.u_bbr.pkts_out = rack->rc_tp->t_maxseg;
2021 		log.u_bbr.delRate = rack->r_ctl.crte_prev_rate;
2022 		if (rack->r_ctl.crte)
2023 			log.u_bbr.cur_del_rate = rack->r_ctl.crte->rate;
2024 		else
2025 			log.u_bbr.cur_del_rate = 0;
2026 		log.u_bbr.rttProp = rack->r_ctl.last_hw_bw_req;
2027 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2028 		    &rack->rc_inp->inp_socket->so_rcv,
2029 		    &rack->rc_inp->inp_socket->so_snd,
2030 		    BBR_LOG_HDWR_PACE, 0,
2031 		    0, &log, false, &tv);
2032 	}
2033 }
2034 
2035 static uint64_t
2036 rack_get_output_bw(struct tcp_rack *rack, uint64_t bw, struct rack_sendmap *rsm, int *capped)
2037 {
2038 	/*
2039 	 * We allow rack_per_of_gp_xx to dictate our bw rate we want.
2040 	 */
2041 	uint64_t bw_est, high_rate;
2042 	uint64_t gain;
2043 
2044 	gain = (uint64_t)rack_get_output_gain(rack, rsm);
2045 	bw_est = bw * gain;
2046 	bw_est /= (uint64_t)100;
2047 	/* Never fall below the minimum (def 64kbps) */
2048 	if (bw_est < RACK_MIN_BW)
2049 		bw_est = RACK_MIN_BW;
2050 	if (rack->r_rack_hw_rate_caps) {
2051 		/* Rate caps are in place */
2052 		if (rack->r_ctl.crte != NULL) {
2053 			/* We have a hdwr rate already */
2054 			high_rate = tcp_hw_highest_rate(rack->r_ctl.crte);
2055 			if (bw_est >= high_rate) {
2056 				/* We are capping bw at the highest rate table entry */
2057 				rack_log_hdwr_pacing(rack,
2058 						     bw_est, high_rate, __LINE__,
2059 						     0, 3);
2060 				bw_est = high_rate;
2061 				if (capped)
2062 					*capped = 1;
2063 			}
2064 		} else if ((rack->rack_hdrw_pacing == 0) &&
2065 			   (rack->rack_hdw_pace_ena) &&
2066 			   (rack->rack_attempt_hdwr_pace == 0) &&
2067 			   (rack->rc_inp->inp_route.ro_nh != NULL) &&
2068 			   (rack->rc_inp->inp_route.ro_nh->nh_ifp != NULL)) {
2069 			/*
2070 			 * Special case, we have not yet attempted hardware
2071 			 * pacing, and yet we may, when we do, find out if we are
2072 			 * above the highest rate. We need to know the maxbw for the interface
2073 			 * in question (if it supports ratelimiting). We get back
2074 			 * a 0, if the interface is not found in the RL lists.
2075 			 */
2076 			high_rate = tcp_hw_highest_rate_ifp(rack->rc_inp->inp_route.ro_nh->nh_ifp, rack->rc_inp);
2077 			if (high_rate) {
2078 				/* Yep, we have a rate is it above this rate? */
2079 				if (bw_est > high_rate) {
2080 					bw_est = high_rate;
2081 					if (capped)
2082 						*capped = 1;
2083 				}
2084 			}
2085 		}
2086 	}
2087 	return (bw_est);
2088 }
2089 
2090 static void
2091 rack_log_retran_reason(struct tcp_rack *rack, struct rack_sendmap *rsm, uint32_t tsused, uint32_t thresh, int mod)
2092 {
2093 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2094 		union tcp_log_stackspecific log;
2095 		struct timeval tv;
2096 
2097 		if ((mod != 1) && (rack_verbose_logging == 0)) {
2098 			/*
2099 			 * We get 3 values currently for mod
2100 			 * 1 - We are retransmitting and this tells the reason.
2101 			 * 2 - We are clearing a dup-ack count.
2102 			 * 3 - We are incrementing a dup-ack count.
2103 			 *
2104 			 * The clear/increment are only logged
2105 			 * if you have BBverbose on.
2106 			 */
2107 			return;
2108 		}
2109 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2110 		log.u_bbr.flex1 = tsused;
2111 		log.u_bbr.flex2 = thresh;
2112 		log.u_bbr.flex3 = rsm->r_flags;
2113 		log.u_bbr.flex4 = rsm->r_dupack;
2114 		log.u_bbr.flex5 = rsm->r_start;
2115 		log.u_bbr.flex6 = rsm->r_end;
2116 		log.u_bbr.flex8 = mod;
2117 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2118 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2119 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2120 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2121 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2122 		log.u_bbr.pacing_gain = rack->r_must_retran;
2123 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2124 		    &rack->rc_inp->inp_socket->so_rcv,
2125 		    &rack->rc_inp->inp_socket->so_snd,
2126 		    BBR_LOG_SETTINGS_CHG, 0,
2127 		    0, &log, false, &tv);
2128 	}
2129 }
2130 
2131 static void
2132 rack_log_to_start(struct tcp_rack *rack, uint32_t cts, uint32_t to, int32_t slot, uint8_t which)
2133 {
2134 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2135 		union tcp_log_stackspecific log;
2136 		struct timeval tv;
2137 
2138 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2139 		log.u_bbr.flex1 = rack->rc_tp->t_srtt;
2140 		log.u_bbr.flex2 = to;
2141 		log.u_bbr.flex3 = rack->r_ctl.rc_hpts_flags;
2142 		log.u_bbr.flex4 = slot;
2143 		log.u_bbr.flex5 = rack->rc_inp->inp_hptsslot;
2144 		log.u_bbr.flex6 = rack->rc_tp->t_rxtcur;
2145 		log.u_bbr.flex7 = rack->rc_in_persist;
2146 		log.u_bbr.flex8 = which;
2147 		if (rack->rack_no_prr)
2148 			log.u_bbr.pkts_out = 0;
2149 		else
2150 			log.u_bbr.pkts_out = rack->r_ctl.rc_prr_sndcnt;
2151 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2152 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2153 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2154 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2155 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2156 		log.u_bbr.pacing_gain = rack->r_must_retran;
2157 		log.u_bbr.cwnd_gain = rack->rc_has_collapsed;
2158 		log.u_bbr.lt_epoch = rack->rc_tp->t_rxtshift;
2159 		log.u_bbr.lost = rack_rto_min;
2160 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2161 		    &rack->rc_inp->inp_socket->so_rcv,
2162 		    &rack->rc_inp->inp_socket->so_snd,
2163 		    BBR_LOG_TIMERSTAR, 0,
2164 		    0, &log, false, &tv);
2165 	}
2166 }
2167 
2168 static void
2169 rack_log_to_event(struct tcp_rack *rack, int32_t to_num, struct rack_sendmap *rsm)
2170 {
2171 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2172 		union tcp_log_stackspecific log;
2173 		struct timeval tv;
2174 
2175 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2176 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2177 		log.u_bbr.flex8 = to_num;
2178 		log.u_bbr.flex1 = rack->r_ctl.rc_rack_min_rtt;
2179 		log.u_bbr.flex2 = rack->rc_rack_rtt;
2180 		if (rsm == NULL)
2181 			log.u_bbr.flex3 = 0;
2182 		else
2183 			log.u_bbr.flex3 = rsm->r_end - rsm->r_start;
2184 		if (rack->rack_no_prr)
2185 			log.u_bbr.flex5 = 0;
2186 		else
2187 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
2188 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2189 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2190 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2191 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2192 		log.u_bbr.pacing_gain = rack->r_must_retran;
2193 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2194 		    &rack->rc_inp->inp_socket->so_rcv,
2195 		    &rack->rc_inp->inp_socket->so_snd,
2196 		    BBR_LOG_RTO, 0,
2197 		    0, &log, false, &tv);
2198 	}
2199 }
2200 
2201 static void
2202 rack_log_map_chg(struct tcpcb *tp, struct tcp_rack *rack,
2203 		 struct rack_sendmap *prev,
2204 		 struct rack_sendmap *rsm,
2205 		 struct rack_sendmap *next,
2206 		 int flag, uint32_t th_ack, int line)
2207 {
2208 	if (rack_verbose_logging && (tp->t_logstate != TCP_LOG_STATE_OFF)) {
2209 		union tcp_log_stackspecific log;
2210 		struct timeval tv;
2211 
2212 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2213 		log.u_bbr.flex8 = flag;
2214 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2215 		log.u_bbr.cur_del_rate = (uint64_t)prev;
2216 		log.u_bbr.delRate = (uint64_t)rsm;
2217 		log.u_bbr.rttProp = (uint64_t)next;
2218 		log.u_bbr.flex7 = 0;
2219 		if (prev) {
2220 			log.u_bbr.flex1 = prev->r_start;
2221 			log.u_bbr.flex2 = prev->r_end;
2222 			log.u_bbr.flex7 |= 0x4;
2223 		}
2224 		if (rsm) {
2225 			log.u_bbr.flex3 = rsm->r_start;
2226 			log.u_bbr.flex4 = rsm->r_end;
2227 			log.u_bbr.flex7 |= 0x2;
2228 		}
2229 		if (next) {
2230 			log.u_bbr.flex5 = next->r_start;
2231 			log.u_bbr.flex6 = next->r_end;
2232 			log.u_bbr.flex7 |= 0x1;
2233 		}
2234 		log.u_bbr.applimited = line;
2235 		log.u_bbr.pkts_out = th_ack;
2236 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2237 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2238 		if (rack->rack_no_prr)
2239 			log.u_bbr.lost = 0;
2240 		else
2241 			log.u_bbr.lost = rack->r_ctl.rc_prr_sndcnt;
2242 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2243 		    &rack->rc_inp->inp_socket->so_rcv,
2244 		    &rack->rc_inp->inp_socket->so_snd,
2245 		    TCP_LOG_MAPCHG, 0,
2246 		    0, &log, false, &tv);
2247 	}
2248 }
2249 
2250 static void
2251 rack_log_rtt_upd(struct tcpcb *tp, struct tcp_rack *rack, uint32_t t, uint32_t len,
2252 		 struct rack_sendmap *rsm, int conf)
2253 {
2254 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
2255 		union tcp_log_stackspecific log;
2256 		struct timeval tv;
2257 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2258 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2259 		log.u_bbr.flex1 = t;
2260 		log.u_bbr.flex2 = len;
2261 		log.u_bbr.flex3 = rack->r_ctl.rc_rack_min_rtt;
2262 		log.u_bbr.flex4 = rack->r_ctl.rack_rs.rs_rtt_lowest;
2263 		log.u_bbr.flex5 = rack->r_ctl.rack_rs.rs_rtt_highest;
2264 		log.u_bbr.flex6 = rack->r_ctl.rack_rs.rs_us_rtrcnt;
2265 		log.u_bbr.flex7 = conf;
2266 		log.u_bbr.rttProp = (uint64_t)rack->r_ctl.rack_rs.rs_rtt_tot;
2267 		log.u_bbr.flex8 = rack->r_ctl.rc_rate_sample_method;
2268 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2269 		log.u_bbr.delivered = rack->r_ctl.rack_rs.rs_us_rtrcnt;
2270 		log.u_bbr.pkts_out = rack->r_ctl.rack_rs.rs_flags;
2271 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2272 		if (rsm) {
2273 			log.u_bbr.pkt_epoch = rsm->r_start;
2274 			log.u_bbr.lost = rsm->r_end;
2275 			log.u_bbr.cwnd_gain = rsm->r_rtr_cnt;
2276 			/* We loose any upper of the 24 bits */
2277 			log.u_bbr.pacing_gain = (uint16_t)rsm->r_flags;
2278 		} else {
2279 			/* Its a SYN */
2280 			log.u_bbr.pkt_epoch = rack->rc_tp->iss;
2281 			log.u_bbr.lost = 0;
2282 			log.u_bbr.cwnd_gain = 0;
2283 			log.u_bbr.pacing_gain = 0;
2284 		}
2285 		/* Write out general bits of interest rrs here */
2286 		log.u_bbr.use_lt_bw = rack->rc_highly_buffered;
2287 		log.u_bbr.use_lt_bw <<= 1;
2288 		log.u_bbr.use_lt_bw |= rack->forced_ack;
2289 		log.u_bbr.use_lt_bw <<= 1;
2290 		log.u_bbr.use_lt_bw |= rack->rc_gp_dyn_mul;
2291 		log.u_bbr.use_lt_bw <<= 1;
2292 		log.u_bbr.use_lt_bw |= rack->in_probe_rtt;
2293 		log.u_bbr.use_lt_bw <<= 1;
2294 		log.u_bbr.use_lt_bw |= rack->measure_saw_probe_rtt;
2295 		log.u_bbr.use_lt_bw <<= 1;
2296 		log.u_bbr.use_lt_bw |= rack->app_limited_needs_set;
2297 		log.u_bbr.use_lt_bw <<= 1;
2298 		log.u_bbr.use_lt_bw |= rack->rc_gp_filled;
2299 		log.u_bbr.use_lt_bw <<= 1;
2300 		log.u_bbr.use_lt_bw |= rack->rc_dragged_bottom;
2301 		log.u_bbr.applimited = rack->r_ctl.rc_target_probertt_flight;
2302 		log.u_bbr.epoch = rack->r_ctl.rc_time_probertt_starts;
2303 		log.u_bbr.lt_epoch = rack->r_ctl.rc_time_probertt_entered;
2304 		log.u_bbr.cur_del_rate = rack->r_ctl.rc_lower_rtt_us_cts;
2305 		log.u_bbr.delRate = rack->r_ctl.rc_gp_srtt;
2306 		log.u_bbr.bw_inuse = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
2307 		log.u_bbr.bw_inuse <<= 32;
2308 		if (rsm)
2309 			log.u_bbr.bw_inuse |= ((uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)]);
2310 		TCP_LOG_EVENTP(tp, NULL,
2311 		    &rack->rc_inp->inp_socket->so_rcv,
2312 		    &rack->rc_inp->inp_socket->so_snd,
2313 		    BBR_LOG_BBRRTT, 0,
2314 		    0, &log, false, &tv);
2315 
2316 
2317 	}
2318 }
2319 
2320 static void
2321 rack_log_rtt_sample(struct tcp_rack *rack, uint32_t rtt)
2322 {
2323 	/*
2324 	 * Log the rtt sample we are
2325 	 * applying to the srtt algorithm in
2326 	 * useconds.
2327 	 */
2328 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2329 		union tcp_log_stackspecific log;
2330 		struct timeval tv;
2331 
2332 		/* Convert our ms to a microsecond */
2333 		memset(&log, 0, sizeof(log));
2334 		log.u_bbr.flex1 = rtt;
2335 		log.u_bbr.flex2 = rack->r_ctl.ack_count;
2336 		log.u_bbr.flex3 = rack->r_ctl.sack_count;
2337 		log.u_bbr.flex4 = rack->r_ctl.sack_noextra_move;
2338 		log.u_bbr.flex5 = rack->r_ctl.sack_moved_extra;
2339 		log.u_bbr.flex6 = rack->rc_tp->t_rxtcur;
2340 		log.u_bbr.flex7 = 1;
2341 		log.u_bbr.flex8 = rack->sack_attack_disable;
2342 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2343 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2344 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2345 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2346 		log.u_bbr.pacing_gain = rack->r_must_retran;
2347 		/*
2348 		 * We capture in delRate the upper 32 bits as
2349 		 * the confidence level we had declared, and the
2350 		 * lower 32 bits as the actual RTT using the arrival
2351 		 * timestamp.
2352 		 */
2353 		log.u_bbr.delRate = rack->r_ctl.rack_rs.confidence;
2354 		log.u_bbr.delRate <<= 32;
2355 		log.u_bbr.delRate |= rack->r_ctl.rack_rs.rs_us_rtt;
2356 		/* Lets capture all the things that make up t_rtxcur */
2357 		log.u_bbr.applimited = rack_rto_min;
2358 		log.u_bbr.epoch = rack_rto_max;
2359 		log.u_bbr.lt_epoch = rack->r_ctl.timer_slop;
2360 		log.u_bbr.lost = rack_rto_min;
2361 		log.u_bbr.pkt_epoch = TICKS_2_USEC(tcp_rexmit_slop);
2362 		log.u_bbr.rttProp = RACK_REXMTVAL(rack->rc_tp);
2363 		log.u_bbr.bw_inuse = rack->r_ctl.act_rcv_time.tv_sec;
2364 		log.u_bbr.bw_inuse *= HPTS_USEC_IN_SEC;
2365 		log.u_bbr.bw_inuse += rack->r_ctl.act_rcv_time.tv_usec;
2366 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2367 		    &rack->rc_inp->inp_socket->so_rcv,
2368 		    &rack->rc_inp->inp_socket->so_snd,
2369 		    TCP_LOG_RTT, 0,
2370 		    0, &log, false, &tv);
2371 	}
2372 }
2373 
2374 static void
2375 rack_log_rtt_sample_calc(struct tcp_rack *rack, uint32_t rtt, uint32_t send_time, uint32_t ack_time, int where)
2376 {
2377 	if (rack_verbose_logging && (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2378 		union tcp_log_stackspecific log;
2379 		struct timeval tv;
2380 
2381 		/* Convert our ms to a microsecond */
2382 		memset(&log, 0, sizeof(log));
2383 		log.u_bbr.flex1 = rtt;
2384 		log.u_bbr.flex2 = send_time;
2385 		log.u_bbr.flex3 = ack_time;
2386 		log.u_bbr.flex4 = where;
2387 		log.u_bbr.flex7 = 2;
2388 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2389 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2390 		    &rack->rc_inp->inp_socket->so_rcv,
2391 		    &rack->rc_inp->inp_socket->so_snd,
2392 		    TCP_LOG_RTT, 0,
2393 		    0, &log, false, &tv);
2394 	}
2395 }
2396 
2397 
2398 
2399 static inline void
2400 rack_log_progress_event(struct tcp_rack *rack, struct tcpcb *tp, uint32_t tick,  int event, int line)
2401 {
2402 	if (rack_verbose_logging && (tp->t_logstate != TCP_LOG_STATE_OFF)) {
2403 		union tcp_log_stackspecific log;
2404 		struct timeval tv;
2405 
2406 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2407 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2408 		log.u_bbr.flex1 = line;
2409 		log.u_bbr.flex2 = tick;
2410 		log.u_bbr.flex3 = tp->t_maxunacktime;
2411 		log.u_bbr.flex4 = tp->t_acktime;
2412 		log.u_bbr.flex8 = event;
2413 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2414 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2415 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2416 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2417 		log.u_bbr.pacing_gain = rack->r_must_retran;
2418 		TCP_LOG_EVENTP(tp, NULL,
2419 		    &rack->rc_inp->inp_socket->so_rcv,
2420 		    &rack->rc_inp->inp_socket->so_snd,
2421 		    BBR_LOG_PROGRESS, 0,
2422 		    0, &log, false, &tv);
2423 	}
2424 }
2425 
2426 static void
2427 rack_log_type_bbrsnd(struct tcp_rack *rack, uint32_t len, uint32_t slot, uint32_t cts, struct timeval *tv)
2428 {
2429 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2430 		union tcp_log_stackspecific log;
2431 
2432 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2433 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2434 		log.u_bbr.flex1 = slot;
2435 		if (rack->rack_no_prr)
2436 			log.u_bbr.flex2 = 0;
2437 		else
2438 			log.u_bbr.flex2 = rack->r_ctl.rc_prr_sndcnt;
2439 		log.u_bbr.flex7 = (0x0000ffff & rack->r_ctl.rc_hpts_flags);
2440 		log.u_bbr.flex8 = rack->rc_in_persist;
2441 		log.u_bbr.timeStamp = cts;
2442 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2443 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2444 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2445 		log.u_bbr.pacing_gain = rack->r_must_retran;
2446 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2447 		    &rack->rc_inp->inp_socket->so_rcv,
2448 		    &rack->rc_inp->inp_socket->so_snd,
2449 		    BBR_LOG_BBRSND, 0,
2450 		    0, &log, false, tv);
2451 	}
2452 }
2453 
2454 static void
2455 rack_log_doseg_done(struct tcp_rack *rack, uint32_t cts, int32_t nxt_pkt, int32_t did_out, int way_out, int nsegs)
2456 {
2457 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2458 		union tcp_log_stackspecific log;
2459 		struct timeval tv;
2460 
2461 		memset(&log, 0, sizeof(log));
2462 		log.u_bbr.flex1 = did_out;
2463 		log.u_bbr.flex2 = nxt_pkt;
2464 		log.u_bbr.flex3 = way_out;
2465 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
2466 		if (rack->rack_no_prr)
2467 			log.u_bbr.flex5 = 0;
2468 		else
2469 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
2470 		log.u_bbr.flex6 = nsegs;
2471 		log.u_bbr.applimited = rack->r_ctl.rc_pace_min_segs;
2472 		log.u_bbr.flex7 = rack->rc_ack_can_sendout_data;	/* Do we have ack-can-send set */
2473 		log.u_bbr.flex7 <<= 1;
2474 		log.u_bbr.flex7 |= rack->r_fast_output;	/* is fast output primed */
2475 		log.u_bbr.flex7 <<= 1;
2476 		log.u_bbr.flex7 |= rack->r_wanted_output;	/* Do we want output */
2477 		log.u_bbr.flex8 = rack->rc_in_persist;
2478 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2479 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2480 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2481 		log.u_bbr.use_lt_bw = rack->r_ent_rec_ns;
2482 		log.u_bbr.use_lt_bw <<= 1;
2483 		log.u_bbr.use_lt_bw |= rack->r_might_revert;
2484 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2485 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2486 		log.u_bbr.pacing_gain = rack->r_must_retran;
2487 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2488 		    &rack->rc_inp->inp_socket->so_rcv,
2489 		    &rack->rc_inp->inp_socket->so_snd,
2490 		    BBR_LOG_DOSEG_DONE, 0,
2491 		    0, &log, false, &tv);
2492 	}
2493 }
2494 
2495 static void
2496 rack_log_type_pacing_sizes(struct tcpcb *tp, struct tcp_rack *rack, uint32_t arg1, uint32_t arg2, uint32_t arg3, uint8_t frm)
2497 {
2498 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
2499 		union tcp_log_stackspecific log;
2500 		struct timeval tv;
2501 
2502 		memset(&log, 0, sizeof(log));
2503 		log.u_bbr.flex1 = rack->r_ctl.rc_pace_min_segs;
2504 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_max_segs;
2505 		log.u_bbr.flex4 = arg1;
2506 		log.u_bbr.flex5 = arg2;
2507 		log.u_bbr.flex6 = arg3;
2508 		log.u_bbr.flex8 = frm;
2509 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2510 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2511 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2512 		log.u_bbr.applimited = rack->r_ctl.rc_sacked;
2513 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2514 		log.u_bbr.pacing_gain = rack->r_must_retran;
2515 		TCP_LOG_EVENTP(tp, NULL, &tptosocket(tp)->so_rcv,
2516 		    &tptosocket(tp)->so_snd,
2517 		    TCP_HDWR_PACE_SIZE, 0, 0, &log, false, &tv);
2518 	}
2519 }
2520 
2521 static void
2522 rack_log_type_just_return(struct tcp_rack *rack, uint32_t cts, uint32_t tlen, uint32_t slot,
2523 			  uint8_t hpts_calling, int reason, uint32_t cwnd_to_use)
2524 {
2525 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2526 		union tcp_log_stackspecific log;
2527 		struct timeval tv;
2528 
2529 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2530 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2531 		log.u_bbr.flex1 = slot;
2532 		log.u_bbr.flex2 = rack->r_ctl.rc_hpts_flags;
2533 		log.u_bbr.flex4 = reason;
2534 		if (rack->rack_no_prr)
2535 			log.u_bbr.flex5 = 0;
2536 		else
2537 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
2538 		log.u_bbr.flex7 = hpts_calling;
2539 		log.u_bbr.flex8 = rack->rc_in_persist;
2540 		log.u_bbr.lt_epoch = cwnd_to_use;
2541 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2542 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2543 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2544 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2545 		log.u_bbr.pacing_gain = rack->r_must_retran;
2546 		log.u_bbr.cwnd_gain = rack->rc_has_collapsed;
2547 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2548 		    &rack->rc_inp->inp_socket->so_rcv,
2549 		    &rack->rc_inp->inp_socket->so_snd,
2550 		    BBR_LOG_JUSTRET, 0,
2551 		    tlen, &log, false, &tv);
2552 	}
2553 }
2554 
2555 static void
2556 rack_log_to_cancel(struct tcp_rack *rack, int32_t hpts_removed, int line, uint32_t us_cts,
2557 		   struct timeval *tv, uint32_t flags_on_entry)
2558 {
2559 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2560 		union tcp_log_stackspecific log;
2561 
2562 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2563 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
2564 		log.u_bbr.flex1 = line;
2565 		log.u_bbr.flex2 = rack->r_ctl.rc_last_output_to;
2566 		log.u_bbr.flex3 = flags_on_entry;
2567 		log.u_bbr.flex4 = us_cts;
2568 		if (rack->rack_no_prr)
2569 			log.u_bbr.flex5 = 0;
2570 		else
2571 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
2572 		log.u_bbr.flex6 = rack->rc_tp->t_rxtcur;
2573 		log.u_bbr.flex7 = hpts_removed;
2574 		log.u_bbr.flex8 = 1;
2575 		log.u_bbr.applimited = rack->r_ctl.rc_hpts_flags;
2576 		log.u_bbr.timeStamp = us_cts;
2577 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2578 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2579 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2580 		log.u_bbr.pacing_gain = rack->r_must_retran;
2581 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2582 		    &rack->rc_inp->inp_socket->so_rcv,
2583 		    &rack->rc_inp->inp_socket->so_snd,
2584 		    BBR_LOG_TIMERCANC, 0,
2585 		    0, &log, false, tv);
2586 	}
2587 }
2588 
2589 static void
2590 rack_log_alt_to_to_cancel(struct tcp_rack *rack,
2591 			  uint32_t flex1, uint32_t flex2,
2592 			  uint32_t flex3, uint32_t flex4,
2593 			  uint32_t flex5, uint32_t flex6,
2594 			  uint16_t flex7, uint8_t mod)
2595 {
2596 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2597 		union tcp_log_stackspecific log;
2598 		struct timeval tv;
2599 
2600 		if (mod == 1) {
2601 			/* No you can't use 1, its for the real to cancel */
2602 			return;
2603 		}
2604 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2605 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2606 		log.u_bbr.flex1 = flex1;
2607 		log.u_bbr.flex2 = flex2;
2608 		log.u_bbr.flex3 = flex3;
2609 		log.u_bbr.flex4 = flex4;
2610 		log.u_bbr.flex5 = flex5;
2611 		log.u_bbr.flex6 = flex6;
2612 		log.u_bbr.flex7 = flex7;
2613 		log.u_bbr.flex8 = mod;
2614 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2615 		    &rack->rc_inp->inp_socket->so_rcv,
2616 		    &rack->rc_inp->inp_socket->so_snd,
2617 		    BBR_LOG_TIMERCANC, 0,
2618 		    0, &log, false, &tv);
2619 	}
2620 }
2621 
2622 static void
2623 rack_log_to_processing(struct tcp_rack *rack, uint32_t cts, int32_t ret, int32_t timers)
2624 {
2625 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2626 		union tcp_log_stackspecific log;
2627 		struct timeval tv;
2628 
2629 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2630 		log.u_bbr.flex1 = timers;
2631 		log.u_bbr.flex2 = ret;
2632 		log.u_bbr.flex3 = rack->r_ctl.rc_timer_exp;
2633 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
2634 		log.u_bbr.flex5 = cts;
2635 		if (rack->rack_no_prr)
2636 			log.u_bbr.flex6 = 0;
2637 		else
2638 			log.u_bbr.flex6 = rack->r_ctl.rc_prr_sndcnt;
2639 		log.u_bbr.pkts_out = rack->r_ctl.rc_out_at_rto;
2640 		log.u_bbr.delivered = rack->r_ctl.rc_snd_max_at_rto;
2641 		log.u_bbr.pacing_gain = rack->r_must_retran;
2642 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2643 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2644 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2645 		    &rack->rc_inp->inp_socket->so_rcv,
2646 		    &rack->rc_inp->inp_socket->so_snd,
2647 		    BBR_LOG_TO_PROCESS, 0,
2648 		    0, &log, false, &tv);
2649 	}
2650 }
2651 
2652 static void
2653 rack_log_to_prr(struct tcp_rack *rack, int frm, int orig_cwnd, int line)
2654 {
2655 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2656 		union tcp_log_stackspecific log;
2657 		struct timeval tv;
2658 
2659 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2660 		log.u_bbr.flex1 = rack->r_ctl.rc_prr_out;
2661 		log.u_bbr.flex2 = rack->r_ctl.rc_prr_recovery_fs;
2662 		if (rack->rack_no_prr)
2663 			log.u_bbr.flex3 = 0;
2664 		else
2665 			log.u_bbr.flex3 = rack->r_ctl.rc_prr_sndcnt;
2666 		log.u_bbr.flex4 = rack->r_ctl.rc_prr_delivered;
2667 		log.u_bbr.flex5 = rack->r_ctl.rc_sacked;
2668 		log.u_bbr.flex6 = rack->r_ctl.rc_holes_rxt;
2669 		log.u_bbr.flex7 = line;
2670 		log.u_bbr.flex8 = frm;
2671 		log.u_bbr.pkts_out = orig_cwnd;
2672 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2673 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2674 		log.u_bbr.use_lt_bw = rack->r_ent_rec_ns;
2675 		log.u_bbr.use_lt_bw <<= 1;
2676 		log.u_bbr.use_lt_bw |= rack->r_might_revert;
2677 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2678 		    &rack->rc_inp->inp_socket->so_rcv,
2679 		    &rack->rc_inp->inp_socket->so_snd,
2680 		    BBR_LOG_BBRUPD, 0,
2681 		    0, &log, false, &tv);
2682 	}
2683 }
2684 
2685 #ifdef NETFLIX_EXP_DETECTION
2686 static void
2687 rack_log_sad(struct tcp_rack *rack, int event)
2688 {
2689 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2690 		union tcp_log_stackspecific log;
2691 		struct timeval tv;
2692 
2693 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2694 		log.u_bbr.flex1 = rack->r_ctl.sack_count;
2695 		log.u_bbr.flex2 = rack->r_ctl.ack_count;
2696 		log.u_bbr.flex3 = rack->r_ctl.sack_moved_extra;
2697 		log.u_bbr.flex4 = rack->r_ctl.sack_noextra_move;
2698 		log.u_bbr.flex5 = rack->r_ctl.rc_num_maps_alloced;
2699 		log.u_bbr.flex6 = tcp_sack_to_ack_thresh;
2700 		log.u_bbr.pkts_out = tcp_sack_to_move_thresh;
2701 		log.u_bbr.lt_epoch = (tcp_force_detection << 8);
2702 		log.u_bbr.lt_epoch |= rack->do_detection;
2703 		log.u_bbr.applimited = tcp_map_minimum;
2704 		log.u_bbr.flex7 = rack->sack_attack_disable;
2705 		log.u_bbr.flex8 = event;
2706 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2707 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2708 		log.u_bbr.delivered = tcp_sad_decay_val;
2709 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2710 		    &rack->rc_inp->inp_socket->so_rcv,
2711 		    &rack->rc_inp->inp_socket->so_snd,
2712 		    TCP_SAD_DETECTION, 0,
2713 		    0, &log, false, &tv);
2714 	}
2715 }
2716 #endif
2717 
2718 static void
2719 rack_counter_destroy(void)
2720 {
2721 	counter_u64_free(rack_fto_send);
2722 	counter_u64_free(rack_fto_rsm_send);
2723 	counter_u64_free(rack_nfto_resend);
2724 	counter_u64_free(rack_hw_pace_init_fail);
2725 	counter_u64_free(rack_hw_pace_lost);
2726 	counter_u64_free(rack_non_fto_send);
2727 	counter_u64_free(rack_extended_rfo);
2728 	counter_u64_free(rack_ack_total);
2729 	counter_u64_free(rack_express_sack);
2730 	counter_u64_free(rack_sack_total);
2731 	counter_u64_free(rack_move_none);
2732 	counter_u64_free(rack_move_some);
2733 	counter_u64_free(rack_sack_attacks_detected);
2734 	counter_u64_free(rack_sack_attacks_reversed);
2735 	counter_u64_free(rack_sack_used_next_merge);
2736 	counter_u64_free(rack_sack_used_prev_merge);
2737 	counter_u64_free(rack_tlp_tot);
2738 	counter_u64_free(rack_tlp_newdata);
2739 	counter_u64_free(rack_tlp_retran);
2740 	counter_u64_free(rack_tlp_retran_bytes);
2741 	counter_u64_free(rack_to_tot);
2742 	counter_u64_free(rack_saw_enobuf);
2743 	counter_u64_free(rack_saw_enobuf_hw);
2744 	counter_u64_free(rack_saw_enetunreach);
2745 	counter_u64_free(rack_hot_alloc);
2746 	counter_u64_free(rack_to_alloc);
2747 	counter_u64_free(rack_to_alloc_hard);
2748 	counter_u64_free(rack_to_alloc_emerg);
2749 	counter_u64_free(rack_to_alloc_limited);
2750 	counter_u64_free(rack_alloc_limited_conns);
2751 	counter_u64_free(rack_split_limited);
2752 	counter_u64_free(rack_multi_single_eq);
2753 	counter_u64_free(rack_proc_non_comp_ack);
2754 	counter_u64_free(rack_sack_proc_all);
2755 	counter_u64_free(rack_sack_proc_restart);
2756 	counter_u64_free(rack_sack_proc_short);
2757 	counter_u64_free(rack_sack_skipped_acked);
2758 	counter_u64_free(rack_sack_splits);
2759 	counter_u64_free(rack_input_idle_reduces);
2760 	counter_u64_free(rack_collapsed_win);
2761 	counter_u64_free(rack_collapsed_win_rxt);
2762 	counter_u64_free(rack_collapsed_win_rxt_bytes);
2763 	counter_u64_free(rack_collapsed_win_seen);
2764 	counter_u64_free(rack_try_scwnd);
2765 	counter_u64_free(rack_persists_sends);
2766 	counter_u64_free(rack_persists_acks);
2767 	counter_u64_free(rack_persists_loss);
2768 	counter_u64_free(rack_persists_lost_ends);
2769 #ifdef INVARIANTS
2770 	counter_u64_free(rack_adjust_map_bw);
2771 #endif
2772 	COUNTER_ARRAY_FREE(rack_out_size, TCP_MSS_ACCT_SIZE);
2773 	COUNTER_ARRAY_FREE(rack_opts_arry, RACK_OPTS_SIZE);
2774 }
2775 
2776 static struct rack_sendmap *
2777 rack_alloc(struct tcp_rack *rack)
2778 {
2779 	struct rack_sendmap *rsm;
2780 
2781 	/*
2782 	 * First get the top of the list it in
2783 	 * theory is the "hottest" rsm we have,
2784 	 * possibly just freed by ack processing.
2785 	 */
2786 	if (rack->rc_free_cnt > rack_free_cache) {
2787 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
2788 		TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_tnext);
2789 		counter_u64_add(rack_hot_alloc, 1);
2790 		rack->rc_free_cnt--;
2791 		return (rsm);
2792 	}
2793 	/*
2794 	 * Once we get under our free cache we probably
2795 	 * no longer have a "hot" one available. Lets
2796 	 * get one from UMA.
2797 	 */
2798 	rsm = uma_zalloc(rack_zone, M_NOWAIT);
2799 	if (rsm) {
2800 		rack->r_ctl.rc_num_maps_alloced++;
2801 		counter_u64_add(rack_to_alloc, 1);
2802 		return (rsm);
2803 	}
2804 	/*
2805 	 * Dig in to our aux rsm's (the last two) since
2806 	 * UMA failed to get us one.
2807 	 */
2808 	if (rack->rc_free_cnt) {
2809 		counter_u64_add(rack_to_alloc_emerg, 1);
2810 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
2811 		TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_tnext);
2812 		rack->rc_free_cnt--;
2813 		return (rsm);
2814 	}
2815 	return (NULL);
2816 }
2817 
2818 static struct rack_sendmap *
2819 rack_alloc_full_limit(struct tcp_rack *rack)
2820 {
2821 	if ((V_tcp_map_entries_limit > 0) &&
2822 	    (rack->do_detection == 0) &&
2823 	    (rack->r_ctl.rc_num_maps_alloced >= V_tcp_map_entries_limit)) {
2824 		counter_u64_add(rack_to_alloc_limited, 1);
2825 		if (!rack->alloc_limit_reported) {
2826 			rack->alloc_limit_reported = 1;
2827 			counter_u64_add(rack_alloc_limited_conns, 1);
2828 		}
2829 		return (NULL);
2830 	}
2831 	return (rack_alloc(rack));
2832 }
2833 
2834 /* wrapper to allocate a sendmap entry, subject to a specific limit */
2835 static struct rack_sendmap *
2836 rack_alloc_limit(struct tcp_rack *rack, uint8_t limit_type)
2837 {
2838 	struct rack_sendmap *rsm;
2839 
2840 	if (limit_type) {
2841 		/* currently there is only one limit type */
2842 		if (V_tcp_map_split_limit > 0 &&
2843 		    (rack->do_detection == 0) &&
2844 		    rack->r_ctl.rc_num_split_allocs >= V_tcp_map_split_limit) {
2845 			counter_u64_add(rack_split_limited, 1);
2846 			if (!rack->alloc_limit_reported) {
2847 				rack->alloc_limit_reported = 1;
2848 				counter_u64_add(rack_alloc_limited_conns, 1);
2849 			}
2850 			return (NULL);
2851 		}
2852 	}
2853 
2854 	/* allocate and mark in the limit type, if set */
2855 	rsm = rack_alloc(rack);
2856 	if (rsm != NULL && limit_type) {
2857 		rsm->r_limit_type = limit_type;
2858 		rack->r_ctl.rc_num_split_allocs++;
2859 	}
2860 	return (rsm);
2861 }
2862 
2863 static void
2864 rack_free(struct tcp_rack *rack, struct rack_sendmap *rsm)
2865 {
2866 	if (rsm->r_flags & RACK_APP_LIMITED) {
2867 		if (rack->r_ctl.rc_app_limited_cnt > 0) {
2868 			rack->r_ctl.rc_app_limited_cnt--;
2869 		}
2870 	}
2871 	if (rsm->r_limit_type) {
2872 		/* currently there is only one limit type */
2873 		rack->r_ctl.rc_num_split_allocs--;
2874 	}
2875 	if (rsm == rack->r_ctl.rc_first_appl) {
2876 		if (rack->r_ctl.rc_app_limited_cnt == 0)
2877 			rack->r_ctl.rc_first_appl = NULL;
2878 		else {
2879 			/* Follow the next one out */
2880 			struct rack_sendmap fe;
2881 
2882 			fe.r_start = rsm->r_nseq_appl;
2883 			rack->r_ctl.rc_first_appl = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
2884 		}
2885 	}
2886 	if (rsm == rack->r_ctl.rc_resend)
2887 		rack->r_ctl.rc_resend = NULL;
2888 	if (rsm == rack->r_ctl.rc_end_appl)
2889 		rack->r_ctl.rc_end_appl = NULL;
2890 	if (rack->r_ctl.rc_tlpsend == rsm)
2891 		rack->r_ctl.rc_tlpsend = NULL;
2892 	if (rack->r_ctl.rc_sacklast == rsm)
2893 		rack->r_ctl.rc_sacklast = NULL;
2894 	memset(rsm, 0, sizeof(struct rack_sendmap));
2895 	TAILQ_INSERT_HEAD(&rack->r_ctl.rc_free, rsm, r_tnext);
2896 	rack->rc_free_cnt++;
2897 }
2898 
2899 static void
2900 rack_free_trim(struct tcp_rack *rack)
2901 {
2902 	struct rack_sendmap *rsm;
2903 
2904 	/*
2905 	 * Free up all the tail entries until
2906 	 * we get our list down to the limit.
2907 	 */
2908 	while (rack->rc_free_cnt > rack_free_cache) {
2909 		rsm = TAILQ_LAST(&rack->r_ctl.rc_free, rack_head);
2910 		TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_tnext);
2911 		rack->rc_free_cnt--;
2912 		uma_zfree(rack_zone, rsm);
2913 	}
2914 }
2915 
2916 
2917 static uint32_t
2918 rack_get_measure_window(struct tcpcb *tp, struct tcp_rack *rack)
2919 {
2920 	uint64_t srtt, bw, len, tim;
2921 	uint32_t segsiz, def_len, minl;
2922 
2923 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
2924 	def_len = rack_def_data_window * segsiz;
2925 	if (rack->rc_gp_filled == 0) {
2926 		/*
2927 		 * We have no measurement (IW is in flight?) so
2928 		 * we can only guess using our data_window sysctl
2929 		 * value (usually 20MSS).
2930 		 */
2931 		return (def_len);
2932 	}
2933 	/*
2934 	 * Now we have a number of factors to consider.
2935 	 *
2936 	 * 1) We have a desired BDP which is usually
2937 	 *    at least 2.
2938 	 * 2) We have a minimum number of rtt's usually 1 SRTT
2939 	 *    but we allow it too to be more.
2940 	 * 3) We want to make sure a measurement last N useconds (if
2941 	 *    we have set rack_min_measure_usec.
2942 	 *
2943 	 * We handle the first concern here by trying to create a data
2944 	 * window of max(rack_def_data_window, DesiredBDP). The
2945 	 * second concern we handle in not letting the measurement
2946 	 * window end normally until at least the required SRTT's
2947 	 * have gone by which is done further below in
2948 	 * rack_enough_for_measurement(). Finally the third concern
2949 	 * we also handle here by calculating how long that time
2950 	 * would take at the current BW and then return the
2951 	 * max of our first calculation and that length. Note
2952 	 * that if rack_min_measure_usec is 0, we don't deal
2953 	 * with concern 3. Also for both Concern 1 and 3 an
2954 	 * application limited period could end the measurement
2955 	 * earlier.
2956 	 *
2957 	 * So lets calculate the BDP with the "known" b/w using
2958 	 * the SRTT has our rtt and then multiply it by the
2959 	 * goal.
2960 	 */
2961 	bw = rack_get_bw(rack);
2962 	srtt = (uint64_t)tp->t_srtt;
2963 	len = bw * srtt;
2964 	len /= (uint64_t)HPTS_USEC_IN_SEC;
2965 	len *= max(1, rack_goal_bdp);
2966 	/* Now we need to round up to the nearest MSS */
2967 	len = roundup(len, segsiz);
2968 	if (rack_min_measure_usec) {
2969 		/* Now calculate our min length for this b/w */
2970 		tim = rack_min_measure_usec;
2971 		minl = (tim * bw) / (uint64_t)HPTS_USEC_IN_SEC;
2972 		if (minl == 0)
2973 			minl = 1;
2974 		minl = roundup(minl, segsiz);
2975 		if (len < minl)
2976 			len = minl;
2977 	}
2978 	/*
2979 	 * Now if we have a very small window we want
2980 	 * to attempt to get the window that is
2981 	 * as small as possible. This happens on
2982 	 * low b/w connections and we don't want to
2983 	 * span huge numbers of rtt's between measurements.
2984 	 *
2985 	 * We basically include 2 over our "MIN window" so
2986 	 * that the measurement can be shortened (possibly) by
2987 	 * an ack'ed packet.
2988 	 */
2989 	if (len < def_len)
2990 		return (max((uint32_t)len, ((MIN_GP_WIN+2) * segsiz)));
2991 	else
2992 		return (max((uint32_t)len, def_len));
2993 
2994 }
2995 
2996 static int
2997 rack_enough_for_measurement(struct tcpcb *tp, struct tcp_rack *rack, tcp_seq th_ack, uint8_t *quality)
2998 {
2999 	uint32_t tim, srtts, segsiz;
3000 
3001 	/*
3002 	 * Has enough time passed for the GP measurement to be valid?
3003 	 */
3004 	if ((tp->snd_max == tp->snd_una) ||
3005 	    (th_ack == tp->snd_max)){
3006 		/* All is acked */
3007 		*quality = RACK_QUALITY_ALLACKED;
3008 		return (1);
3009 	}
3010 	if (SEQ_LT(th_ack, tp->gput_seq)) {
3011 		/* Not enough bytes yet */
3012 		return (0);
3013 	}
3014 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
3015 	if (SEQ_LT(th_ack, tp->gput_ack) &&
3016 	    ((th_ack - tp->gput_seq) < max(rc_init_window(rack), (MIN_GP_WIN * segsiz)))) {
3017 		/* Not enough bytes yet */
3018 		return (0);
3019 	}
3020 	if (rack->r_ctl.rc_first_appl &&
3021 	    (SEQ_GEQ(th_ack, rack->r_ctl.rc_first_appl->r_end))) {
3022 		/*
3023 		 * We are up to the app limited send point
3024 		 * we have to measure irrespective of the time..
3025 		 */
3026 		*quality = RACK_QUALITY_APPLIMITED;
3027 		return (1);
3028 	}
3029 	/* Now what about time? */
3030 	srtts = (rack->r_ctl.rc_gp_srtt * rack_min_srtts);
3031 	tim = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time) - tp->gput_ts;
3032 	if (tim >= srtts) {
3033 		*quality = RACK_QUALITY_HIGH;
3034 		return (1);
3035 	}
3036 	/* Nope not even a full SRTT has passed */
3037 	return (0);
3038 }
3039 
3040 static void
3041 rack_log_timely(struct tcp_rack *rack,
3042 		uint32_t logged, uint64_t cur_bw, uint64_t low_bnd,
3043 		uint64_t up_bnd, int line, uint8_t method)
3044 {
3045 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
3046 		union tcp_log_stackspecific log;
3047 		struct timeval tv;
3048 
3049 		memset(&log, 0, sizeof(log));
3050 		log.u_bbr.flex1 = logged;
3051 		log.u_bbr.flex2 = rack->rc_gp_timely_inc_cnt;
3052 		log.u_bbr.flex2 <<= 4;
3053 		log.u_bbr.flex2 |= rack->rc_gp_timely_dec_cnt;
3054 		log.u_bbr.flex2 <<= 4;
3055 		log.u_bbr.flex2 |= rack->rc_gp_incr;
3056 		log.u_bbr.flex2 <<= 4;
3057 		log.u_bbr.flex2 |= rack->rc_gp_bwred;
3058 		log.u_bbr.flex3 = rack->rc_gp_incr;
3059 		log.u_bbr.flex4 = rack->r_ctl.rack_per_of_gp_ss;
3060 		log.u_bbr.flex5 = rack->r_ctl.rack_per_of_gp_ca;
3061 		log.u_bbr.flex6 = rack->r_ctl.rack_per_of_gp_rec;
3062 		log.u_bbr.flex7 = rack->rc_gp_bwred;
3063 		log.u_bbr.flex8 = method;
3064 		log.u_bbr.cur_del_rate = cur_bw;
3065 		log.u_bbr.delRate = low_bnd;
3066 		log.u_bbr.bw_inuse = up_bnd;
3067 		log.u_bbr.rttProp = rack_get_bw(rack);
3068 		log.u_bbr.pkt_epoch = line;
3069 		log.u_bbr.pkts_out = rack->r_ctl.rc_rtt_diff;
3070 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
3071 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
3072 		log.u_bbr.epoch = rack->r_ctl.rc_gp_srtt;
3073 		log.u_bbr.lt_epoch = rack->r_ctl.rc_prev_gp_srtt;
3074 		log.u_bbr.cwnd_gain = rack->rc_dragged_bottom;
3075 		log.u_bbr.cwnd_gain <<= 1;
3076 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_rec;
3077 		log.u_bbr.cwnd_gain <<= 1;
3078 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ss;
3079 		log.u_bbr.cwnd_gain <<= 1;
3080 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ca;
3081 		log.u_bbr.lost = rack->r_ctl.rc_loss_count;
3082 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
3083 		    &rack->rc_inp->inp_socket->so_rcv,
3084 		    &rack->rc_inp->inp_socket->so_snd,
3085 		    TCP_TIMELY_WORK, 0,
3086 		    0, &log, false, &tv);
3087 	}
3088 }
3089 
3090 static int
3091 rack_bw_can_be_raised(struct tcp_rack *rack, uint64_t cur_bw, uint64_t last_bw_est, uint16_t mult)
3092 {
3093 	/*
3094 	 * Before we increase we need to know if
3095 	 * the estimate just made was less than
3096 	 * our pacing goal (i.e. (cur_bw * mult) > last_bw_est)
3097 	 *
3098 	 * If we already are pacing at a fast enough
3099 	 * rate to push us faster there is no sense of
3100 	 * increasing.
3101 	 *
3102 	 * We first caculate our actual pacing rate (ss or ca multiplier
3103 	 * times our cur_bw).
3104 	 *
3105 	 * Then we take the last measured rate and multipy by our
3106 	 * maximum pacing overage to give us a max allowable rate.
3107 	 *
3108 	 * If our act_rate is smaller than our max_allowable rate
3109 	 * then we should increase. Else we should hold steady.
3110 	 *
3111 	 */
3112 	uint64_t act_rate, max_allow_rate;
3113 
3114 	if (rack_timely_no_stopping)
3115 		return (1);
3116 
3117 	if ((cur_bw == 0) || (last_bw_est == 0)) {
3118 		/*
3119 		 * Initial startup case or
3120 		 * everything is acked case.
3121 		 */
3122 		rack_log_timely(rack,  mult, cur_bw, 0, 0,
3123 				__LINE__, 9);
3124 		return (1);
3125 	}
3126 	if (mult <= 100) {
3127 		/*
3128 		 * We can always pace at or slightly above our rate.
3129 		 */
3130 		rack_log_timely(rack,  mult, cur_bw, 0, 0,
3131 				__LINE__, 9);
3132 		return (1);
3133 	}
3134 	act_rate = cur_bw * (uint64_t)mult;
3135 	act_rate /= 100;
3136 	max_allow_rate = last_bw_est * ((uint64_t)rack_max_per_above + (uint64_t)100);
3137 	max_allow_rate /= 100;
3138 	if (act_rate < max_allow_rate) {
3139 		/*
3140 		 * Here the rate we are actually pacing at
3141 		 * is smaller than 10% above our last measurement.
3142 		 * This means we are pacing below what we would
3143 		 * like to try to achieve (plus some wiggle room).
3144 		 */
3145 		rack_log_timely(rack,  mult, cur_bw, act_rate, max_allow_rate,
3146 				__LINE__, 9);
3147 		return (1);
3148 	} else {
3149 		/*
3150 		 * Here we are already pacing at least rack_max_per_above(10%)
3151 		 * what we are getting back. This indicates most likely
3152 		 * that we are being limited (cwnd/rwnd/app) and can't
3153 		 * get any more b/w. There is no sense of trying to
3154 		 * raise up the pacing rate its not speeding us up
3155 		 * and we already are pacing faster than we are getting.
3156 		 */
3157 		rack_log_timely(rack,  mult, cur_bw, act_rate, max_allow_rate,
3158 				__LINE__, 8);
3159 		return (0);
3160 	}
3161 }
3162 
3163 static void
3164 rack_validate_multipliers_at_or_above100(struct tcp_rack *rack)
3165 {
3166 	/*
3167 	 * When we drag bottom, we want to assure
3168 	 * that no multiplier is below 1.0, if so
3169 	 * we want to restore it to at least that.
3170 	 */
3171 	if (rack->r_ctl.rack_per_of_gp_rec  < 100) {
3172 		/* This is unlikely we usually do not touch recovery */
3173 		rack->r_ctl.rack_per_of_gp_rec = 100;
3174 	}
3175 	if (rack->r_ctl.rack_per_of_gp_ca < 100) {
3176 		rack->r_ctl.rack_per_of_gp_ca = 100;
3177 	}
3178 	if (rack->r_ctl.rack_per_of_gp_ss < 100) {
3179 		rack->r_ctl.rack_per_of_gp_ss = 100;
3180 	}
3181 }
3182 
3183 static void
3184 rack_validate_multipliers_at_or_below_100(struct tcp_rack *rack)
3185 {
3186 	if (rack->r_ctl.rack_per_of_gp_ca > 100) {
3187 		rack->r_ctl.rack_per_of_gp_ca = 100;
3188 	}
3189 	if (rack->r_ctl.rack_per_of_gp_ss > 100) {
3190 		rack->r_ctl.rack_per_of_gp_ss = 100;
3191 	}
3192 }
3193 
3194 static void
3195 rack_increase_bw_mul(struct tcp_rack *rack, int timely_says, uint64_t cur_bw, uint64_t last_bw_est, int override)
3196 {
3197 	int32_t  calc, logged, plus;
3198 
3199 	logged = 0;
3200 
3201 	if (override) {
3202 		/*
3203 		 * override is passed when we are
3204 		 * loosing b/w and making one last
3205 		 * gasp at trying to not loose out
3206 		 * to a new-reno flow.
3207 		 */
3208 		goto extra_boost;
3209 	}
3210 	/* In classic timely we boost by 5x if we have 5 increases in a row, lets not */
3211 	if (rack->rc_gp_incr &&
3212 	    ((rack->rc_gp_timely_inc_cnt + 1) >= RACK_TIMELY_CNT_BOOST)) {
3213 		/*
3214 		 * Reset and get 5 strokes more before the boost. Note
3215 		 * that the count is 0 based so we have to add one.
3216 		 */
3217 extra_boost:
3218 		plus = (uint32_t)rack_gp_increase_per * RACK_TIMELY_CNT_BOOST;
3219 		rack->rc_gp_timely_inc_cnt = 0;
3220 	} else
3221 		plus = (uint32_t)rack_gp_increase_per;
3222 	/* Must be at least 1% increase for true timely increases */
3223 	if ((plus < 1) &&
3224 	    ((rack->r_ctl.rc_rtt_diff <= 0) || (timely_says <= 0)))
3225 		plus = 1;
3226 	if (rack->rc_gp_saw_rec &&
3227 	    (rack->rc_gp_no_rec_chg == 0) &&
3228 	    rack_bw_can_be_raised(rack, cur_bw, last_bw_est,
3229 				  rack->r_ctl.rack_per_of_gp_rec)) {
3230 		/* We have been in recovery ding it too */
3231 		calc = rack->r_ctl.rack_per_of_gp_rec + plus;
3232 		if (calc > 0xffff)
3233 			calc = 0xffff;
3234 		logged |= 1;
3235 		rack->r_ctl.rack_per_of_gp_rec = (uint16_t)calc;
3236 		if (rack_per_upper_bound_ss &&
3237 		    (rack->rc_dragged_bottom == 0) &&
3238 		    (rack->r_ctl.rack_per_of_gp_rec > rack_per_upper_bound_ss))
3239 			rack->r_ctl.rack_per_of_gp_rec = rack_per_upper_bound_ss;
3240 	}
3241 	if (rack->rc_gp_saw_ca &&
3242 	    (rack->rc_gp_saw_ss == 0) &&
3243 	    rack_bw_can_be_raised(rack, cur_bw, last_bw_est,
3244 				  rack->r_ctl.rack_per_of_gp_ca)) {
3245 		/* In CA */
3246 		calc = rack->r_ctl.rack_per_of_gp_ca + plus;
3247 		if (calc > 0xffff)
3248 			calc = 0xffff;
3249 		logged |= 2;
3250 		rack->r_ctl.rack_per_of_gp_ca = (uint16_t)calc;
3251 		if (rack_per_upper_bound_ca &&
3252 		    (rack->rc_dragged_bottom == 0) &&
3253 		    (rack->r_ctl.rack_per_of_gp_ca > rack_per_upper_bound_ca))
3254 			rack->r_ctl.rack_per_of_gp_ca = rack_per_upper_bound_ca;
3255 	}
3256 	if (rack->rc_gp_saw_ss &&
3257 	    rack_bw_can_be_raised(rack, cur_bw, last_bw_est,
3258 				  rack->r_ctl.rack_per_of_gp_ss)) {
3259 		/* In SS */
3260 		calc = rack->r_ctl.rack_per_of_gp_ss + plus;
3261 		if (calc > 0xffff)
3262 			calc = 0xffff;
3263 		rack->r_ctl.rack_per_of_gp_ss = (uint16_t)calc;
3264 		if (rack_per_upper_bound_ss &&
3265 		    (rack->rc_dragged_bottom == 0) &&
3266 		    (rack->r_ctl.rack_per_of_gp_ss > rack_per_upper_bound_ss))
3267 			rack->r_ctl.rack_per_of_gp_ss = rack_per_upper_bound_ss;
3268 		logged |= 4;
3269 	}
3270 	if (logged &&
3271 	    (rack->rc_gp_incr == 0)){
3272 		/* Go into increment mode */
3273 		rack->rc_gp_incr = 1;
3274 		rack->rc_gp_timely_inc_cnt = 0;
3275 	}
3276 	if (rack->rc_gp_incr &&
3277 	    logged &&
3278 	    (rack->rc_gp_timely_inc_cnt < RACK_TIMELY_CNT_BOOST)) {
3279 		rack->rc_gp_timely_inc_cnt++;
3280 	}
3281 	rack_log_timely(rack,  logged, plus, 0, 0,
3282 			__LINE__, 1);
3283 }
3284 
3285 static uint32_t
3286 rack_get_decrease(struct tcp_rack *rack, uint32_t curper, int32_t rtt_diff)
3287 {
3288 	/*
3289 	 * norm_grad = rtt_diff / minrtt;
3290 	 * new_per = curper * (1 - B * norm_grad)
3291 	 *
3292 	 * B = rack_gp_decrease_per (default 10%)
3293 	 * rtt_dif = input var current rtt-diff
3294 	 * curper = input var current percentage
3295 	 * minrtt = from rack filter
3296 	 *
3297 	 */
3298 	uint64_t perf;
3299 
3300 	perf = (((uint64_t)curper * ((uint64_t)1000000 -
3301 		    ((uint64_t)rack_gp_decrease_per * (uint64_t)10000 *
3302 		     (((uint64_t)rtt_diff * (uint64_t)1000000)/
3303 		      (uint64_t)get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt)))/
3304 		     (uint64_t)1000000)) /
3305 		(uint64_t)1000000);
3306 	if (perf > curper) {
3307 		/* TSNH */
3308 		perf = curper - 1;
3309 	}
3310 	return ((uint32_t)perf);
3311 }
3312 
3313 static uint32_t
3314 rack_decrease_highrtt(struct tcp_rack *rack, uint32_t curper, uint32_t rtt)
3315 {
3316 	/*
3317 	 *                                   highrttthresh
3318 	 * result = curper * (1 - (B * ( 1 -  ------          ))
3319 	 *                                     gp_srtt
3320 	 *
3321 	 * B = rack_gp_decrease_per (default 10%)
3322 	 * highrttthresh = filter_min * rack_gp_rtt_maxmul
3323 	 */
3324 	uint64_t perf;
3325 	uint32_t highrttthresh;
3326 
3327 	highrttthresh = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_maxmul;
3328 
3329 	perf = (((uint64_t)curper * ((uint64_t)1000000 -
3330 				     ((uint64_t)rack_gp_decrease_per * ((uint64_t)1000000 -
3331 					((uint64_t)highrttthresh * (uint64_t)1000000) /
3332 						    (uint64_t)rtt)) / 100)) /(uint64_t)1000000);
3333 	return (perf);
3334 }
3335 
3336 static void
3337 rack_decrease_bw_mul(struct tcp_rack *rack, int timely_says, uint32_t rtt, int32_t rtt_diff)
3338 {
3339 	uint64_t logvar, logvar2, logvar3;
3340 	uint32_t logged, new_per, ss_red, ca_red, rec_red, alt, val;
3341 
3342 	if (rack->rc_gp_incr) {
3343 		/* Turn off increment counting */
3344 		rack->rc_gp_incr = 0;
3345 		rack->rc_gp_timely_inc_cnt = 0;
3346 	}
3347 	ss_red = ca_red = rec_red = 0;
3348 	logged = 0;
3349 	/* Calculate the reduction value */
3350 	if (rtt_diff < 0) {
3351 		rtt_diff *= -1;
3352 	}
3353 	/* Must be at least 1% reduction */
3354 	if (rack->rc_gp_saw_rec && (rack->rc_gp_no_rec_chg == 0)) {
3355 		/* We have been in recovery ding it too */
3356 		if (timely_says == 2) {
3357 			new_per = rack_decrease_highrtt(rack, rack->r_ctl.rack_per_of_gp_rec, rtt);
3358 			alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
3359 			if (alt < new_per)
3360 				val = alt;
3361 			else
3362 				val = new_per;
3363 		} else
3364 			 val = new_per = alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
3365 		if (rack->r_ctl.rack_per_of_gp_rec > val) {
3366 			rec_red = (rack->r_ctl.rack_per_of_gp_rec - val);
3367 			rack->r_ctl.rack_per_of_gp_rec = (uint16_t)val;
3368 		} else {
3369 			rack->r_ctl.rack_per_of_gp_rec = rack_per_lower_bound;
3370 			rec_red = 0;
3371 		}
3372 		if (rack_per_lower_bound > rack->r_ctl.rack_per_of_gp_rec)
3373 			rack->r_ctl.rack_per_of_gp_rec = rack_per_lower_bound;
3374 		logged |= 1;
3375 	}
3376 	if (rack->rc_gp_saw_ss) {
3377 		/* Sent in SS */
3378 		if (timely_says == 2) {
3379 			new_per = rack_decrease_highrtt(rack, rack->r_ctl.rack_per_of_gp_ss, rtt);
3380 			alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
3381 			if (alt < new_per)
3382 				val = alt;
3383 			else
3384 				val = new_per;
3385 		} else
3386 			val = new_per = alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_ss, rtt_diff);
3387 		if (rack->r_ctl.rack_per_of_gp_ss > new_per) {
3388 			ss_red = rack->r_ctl.rack_per_of_gp_ss - val;
3389 			rack->r_ctl.rack_per_of_gp_ss = (uint16_t)val;
3390 		} else {
3391 			ss_red = new_per;
3392 			rack->r_ctl.rack_per_of_gp_ss = rack_per_lower_bound;
3393 			logvar = new_per;
3394 			logvar <<= 32;
3395 			logvar |= alt;
3396 			logvar2 = (uint32_t)rtt;
3397 			logvar2 <<= 32;
3398 			logvar2 |= (uint32_t)rtt_diff;
3399 			logvar3 = rack_gp_rtt_maxmul;
3400 			logvar3 <<= 32;
3401 			logvar3 |= get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
3402 			rack_log_timely(rack, timely_says,
3403 					logvar2, logvar3,
3404 					logvar, __LINE__, 10);
3405 		}
3406 		if (rack_per_lower_bound > rack->r_ctl.rack_per_of_gp_ss)
3407 			rack->r_ctl.rack_per_of_gp_ss = rack_per_lower_bound;
3408 		logged |= 4;
3409 	} else if (rack->rc_gp_saw_ca) {
3410 		/* Sent in CA */
3411 		if (timely_says == 2) {
3412 			new_per = rack_decrease_highrtt(rack, rack->r_ctl.rack_per_of_gp_ca, rtt);
3413 			alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
3414 			if (alt < new_per)
3415 				val = alt;
3416 			else
3417 				val = new_per;
3418 		} else
3419 			val = new_per = alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_ca, rtt_diff);
3420 		if (rack->r_ctl.rack_per_of_gp_ca > val) {
3421 			ca_red = rack->r_ctl.rack_per_of_gp_ca - val;
3422 			rack->r_ctl.rack_per_of_gp_ca = (uint16_t)val;
3423 		} else {
3424 			rack->r_ctl.rack_per_of_gp_ca = rack_per_lower_bound;
3425 			ca_red = 0;
3426 			logvar = new_per;
3427 			logvar <<= 32;
3428 			logvar |= alt;
3429 			logvar2 = (uint32_t)rtt;
3430 			logvar2 <<= 32;
3431 			logvar2 |= (uint32_t)rtt_diff;
3432 			logvar3 = rack_gp_rtt_maxmul;
3433 			logvar3 <<= 32;
3434 			logvar3 |= get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
3435 			rack_log_timely(rack, timely_says,
3436 					logvar2, logvar3,
3437 					logvar, __LINE__, 10);
3438 		}
3439 		if (rack_per_lower_bound > rack->r_ctl.rack_per_of_gp_ca)
3440 			rack->r_ctl.rack_per_of_gp_ca = rack_per_lower_bound;
3441 		logged |= 2;
3442 	}
3443 	if (rack->rc_gp_timely_dec_cnt < 0x7) {
3444 		rack->rc_gp_timely_dec_cnt++;
3445 		if (rack_timely_dec_clear &&
3446 		    (rack->rc_gp_timely_dec_cnt == rack_timely_dec_clear))
3447 			rack->rc_gp_timely_dec_cnt = 0;
3448 	}
3449 	logvar = ss_red;
3450 	logvar <<= 32;
3451 	logvar |= ca_red;
3452 	rack_log_timely(rack,  logged, rec_red, rack_per_lower_bound, logvar,
3453 			__LINE__, 2);
3454 }
3455 
3456 static void
3457 rack_log_rtt_shrinks(struct tcp_rack *rack, uint32_t us_cts,
3458 		     uint32_t rtt, uint32_t line, uint8_t reas)
3459 {
3460 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
3461 		union tcp_log_stackspecific log;
3462 		struct timeval tv;
3463 
3464 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
3465 		log.u_bbr.flex1 = line;
3466 		log.u_bbr.flex2 = rack->r_ctl.rc_time_probertt_starts;
3467 		log.u_bbr.flex3 = rack->r_ctl.rc_lower_rtt_us_cts;
3468 		log.u_bbr.flex4 = rack->r_ctl.rack_per_of_gp_ss;
3469 		log.u_bbr.flex5 = rtt;
3470 		log.u_bbr.flex6 = rack->rc_highly_buffered;
3471 		log.u_bbr.flex6 <<= 1;
3472 		log.u_bbr.flex6 |= rack->forced_ack;
3473 		log.u_bbr.flex6 <<= 1;
3474 		log.u_bbr.flex6 |= rack->rc_gp_dyn_mul;
3475 		log.u_bbr.flex6 <<= 1;
3476 		log.u_bbr.flex6 |= rack->in_probe_rtt;
3477 		log.u_bbr.flex6 <<= 1;
3478 		log.u_bbr.flex6 |= rack->measure_saw_probe_rtt;
3479 		log.u_bbr.flex7 = rack->r_ctl.rack_per_of_gp_probertt;
3480 		log.u_bbr.pacing_gain = rack->r_ctl.rack_per_of_gp_ca;
3481 		log.u_bbr.cwnd_gain = rack->r_ctl.rack_per_of_gp_rec;
3482 		log.u_bbr.flex8 = reas;
3483 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
3484 		log.u_bbr.delRate = rack_get_bw(rack);
3485 		log.u_bbr.cur_del_rate = rack->r_ctl.rc_highest_us_rtt;
3486 		log.u_bbr.cur_del_rate <<= 32;
3487 		log.u_bbr.cur_del_rate |= rack->r_ctl.rc_lowest_us_rtt;
3488 		log.u_bbr.applimited = rack->r_ctl.rc_time_probertt_entered;
3489 		log.u_bbr.pkts_out = rack->r_ctl.rc_rtt_diff;
3490 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
3491 		log.u_bbr.epoch = rack->r_ctl.rc_gp_srtt;
3492 		log.u_bbr.lt_epoch = rack->r_ctl.rc_prev_gp_srtt;
3493 		log.u_bbr.pkt_epoch = rack->r_ctl.rc_lower_rtt_us_cts;
3494 		log.u_bbr.delivered = rack->r_ctl.rc_target_probertt_flight;
3495 		log.u_bbr.lost = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
3496 		log.u_bbr.rttProp = us_cts;
3497 		log.u_bbr.rttProp <<= 32;
3498 		log.u_bbr.rttProp |= rack->r_ctl.rc_entry_gp_rtt;
3499 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
3500 		    &rack->rc_inp->inp_socket->so_rcv,
3501 		    &rack->rc_inp->inp_socket->so_snd,
3502 		    BBR_LOG_RTT_SHRINKS, 0,
3503 		    0, &log, false, &rack->r_ctl.act_rcv_time);
3504 	}
3505 }
3506 
3507 static void
3508 rack_set_prtt_target(struct tcp_rack *rack, uint32_t segsiz, uint32_t rtt)
3509 {
3510 	uint64_t bwdp;
3511 
3512 	bwdp = rack_get_bw(rack);
3513 	bwdp *= (uint64_t)rtt;
3514 	bwdp /= (uint64_t)HPTS_USEC_IN_SEC;
3515 	rack->r_ctl.rc_target_probertt_flight = roundup((uint32_t)bwdp, segsiz);
3516 	if (rack->r_ctl.rc_target_probertt_flight < (segsiz * rack_timely_min_segs)) {
3517 		/*
3518 		 * A window protocol must be able to have 4 packets
3519 		 * outstanding as the floor in order to function
3520 		 * (especially considering delayed ack :D).
3521 		 */
3522 		rack->r_ctl.rc_target_probertt_flight = (segsiz * rack_timely_min_segs);
3523 	}
3524 }
3525 
3526 static void
3527 rack_enter_probertt(struct tcp_rack *rack, uint32_t us_cts)
3528 {
3529 	/**
3530 	 * ProbeRTT is a bit different in rack_pacing than in
3531 	 * BBR. It is like BBR in that it uses the lowering of
3532 	 * the RTT as a signal that we saw something new and
3533 	 * counts from there for how long between. But it is
3534 	 * different in that its quite simple. It does not
3535 	 * play with the cwnd and wait until we get down
3536 	 * to N segments outstanding and hold that for
3537 	 * 200ms. Instead it just sets the pacing reduction
3538 	 * rate to a set percentage (70 by default) and hold
3539 	 * that for a number of recent GP Srtt's.
3540 	 */
3541 	uint32_t segsiz;
3542 
3543 	if (rack->rc_gp_dyn_mul == 0)
3544 		return;
3545 
3546 	if (rack->rc_tp->snd_max == rack->rc_tp->snd_una) {
3547 		/* We are idle */
3548 		return;
3549 	}
3550 	if ((rack->rc_tp->t_flags & TF_GPUTINPROG) &&
3551 	    SEQ_GT(rack->rc_tp->snd_una, rack->rc_tp->gput_seq)) {
3552 		/*
3553 		 * Stop the goodput now, the idea here is
3554 		 * that future measurements with in_probe_rtt
3555 		 * won't register if they are not greater so
3556 		 * we want to get what info (if any) is available
3557 		 * now.
3558 		 */
3559 		rack_do_goodput_measurement(rack->rc_tp, rack,
3560 					    rack->rc_tp->snd_una, __LINE__,
3561 					    RACK_QUALITY_PROBERTT);
3562 	}
3563 	rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt;
3564 	rack->r_ctl.rc_time_probertt_entered = us_cts;
3565 	segsiz = min(ctf_fixed_maxseg(rack->rc_tp),
3566 		     rack->r_ctl.rc_pace_min_segs);
3567 	rack->in_probe_rtt = 1;
3568 	rack->measure_saw_probe_rtt = 1;
3569 	rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
3570 	rack->r_ctl.rc_time_probertt_starts = 0;
3571 	rack->r_ctl.rc_entry_gp_rtt = rack->r_ctl.rc_gp_srtt;
3572 	if (rack_probertt_use_min_rtt_entry)
3573 		rack_set_prtt_target(rack, segsiz, get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt));
3574 	else
3575 		rack_set_prtt_target(rack, segsiz, rack->r_ctl.rc_gp_srtt);
3576 	rack_log_rtt_shrinks(rack,  us_cts,  get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3577 			     __LINE__, RACK_RTTS_ENTERPROBE);
3578 }
3579 
3580 static void
3581 rack_exit_probertt(struct tcp_rack *rack, uint32_t us_cts)
3582 {
3583 	struct rack_sendmap *rsm;
3584 	uint32_t segsiz;
3585 
3586 	segsiz = min(ctf_fixed_maxseg(rack->rc_tp),
3587 		     rack->r_ctl.rc_pace_min_segs);
3588 	rack->in_probe_rtt = 0;
3589 	if ((rack->rc_tp->t_flags & TF_GPUTINPROG) &&
3590 	    SEQ_GT(rack->rc_tp->snd_una, rack->rc_tp->gput_seq)) {
3591 		/*
3592 		 * Stop the goodput now, the idea here is
3593 		 * that future measurements with in_probe_rtt
3594 		 * won't register if they are not greater so
3595 		 * we want to get what info (if any) is available
3596 		 * now.
3597 		 */
3598 		rack_do_goodput_measurement(rack->rc_tp, rack,
3599 					    rack->rc_tp->snd_una, __LINE__,
3600 					    RACK_QUALITY_PROBERTT);
3601 	} else if (rack->rc_tp->t_flags & TF_GPUTINPROG) {
3602 		/*
3603 		 * We don't have enough data to make a measurement.
3604 		 * So lets just stop and start here after exiting
3605 		 * probe-rtt. We probably are not interested in
3606 		 * the results anyway.
3607 		 */
3608 		rack->rc_tp->t_flags &= ~TF_GPUTINPROG;
3609 	}
3610 	/*
3611 	 * Measurements through the current snd_max are going
3612 	 * to be limited by the slower pacing rate.
3613 	 *
3614 	 * We need to mark these as app-limited so we
3615 	 * don't collapse the b/w.
3616 	 */
3617 	rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
3618 	if (rsm && ((rsm->r_flags & RACK_APP_LIMITED) == 0)) {
3619 		if (rack->r_ctl.rc_app_limited_cnt == 0)
3620 			rack->r_ctl.rc_end_appl = rack->r_ctl.rc_first_appl = rsm;
3621 		else {
3622 			/*
3623 			 * Go out to the end app limited and mark
3624 			 * this new one as next and move the end_appl up
3625 			 * to this guy.
3626 			 */
3627 			if (rack->r_ctl.rc_end_appl)
3628 				rack->r_ctl.rc_end_appl->r_nseq_appl = rsm->r_start;
3629 			rack->r_ctl.rc_end_appl = rsm;
3630 		}
3631 		rsm->r_flags |= RACK_APP_LIMITED;
3632 		rack->r_ctl.rc_app_limited_cnt++;
3633 	}
3634 	/*
3635 	 * Now, we need to examine our pacing rate multipliers.
3636 	 * If its under 100%, we need to kick it back up to
3637 	 * 100%. We also don't let it be over our "max" above
3638 	 * the actual rate i.e. 100% + rack_clamp_atexit_prtt.
3639 	 * Note setting clamp_atexit_prtt to 0 has the effect
3640 	 * of setting CA/SS to 100% always at exit (which is
3641 	 * the default behavior).
3642 	 */
3643 	if (rack_probertt_clear_is) {
3644 		rack->rc_gp_incr = 0;
3645 		rack->rc_gp_bwred = 0;
3646 		rack->rc_gp_timely_inc_cnt = 0;
3647 		rack->rc_gp_timely_dec_cnt = 0;
3648 	}
3649 	/* Do we do any clamping at exit? */
3650 	if (rack->rc_highly_buffered && rack_atexit_prtt_hbp) {
3651 		rack->r_ctl.rack_per_of_gp_ca = rack_atexit_prtt_hbp;
3652 		rack->r_ctl.rack_per_of_gp_ss = rack_atexit_prtt_hbp;
3653 	}
3654 	if ((rack->rc_highly_buffered == 0) && rack_atexit_prtt) {
3655 		rack->r_ctl.rack_per_of_gp_ca = rack_atexit_prtt;
3656 		rack->r_ctl.rack_per_of_gp_ss = rack_atexit_prtt;
3657 	}
3658 	/*
3659 	 * Lets set rtt_diff to 0, so that we will get a "boost"
3660 	 * after exiting.
3661 	 */
3662 	rack->r_ctl.rc_rtt_diff = 0;
3663 
3664 	/* Clear all flags so we start fresh */
3665 	rack->rc_tp->t_bytes_acked = 0;
3666 	rack->rc_tp->t_ccv.flags &= ~CCF_ABC_SENTAWND;
3667 	/*
3668 	 * If configured to, set the cwnd and ssthresh to
3669 	 * our targets.
3670 	 */
3671 	if (rack_probe_rtt_sets_cwnd) {
3672 		uint64_t ebdp;
3673 		uint32_t setto;
3674 
3675 		/* Set ssthresh so we get into CA once we hit our target */
3676 		if (rack_probertt_use_min_rtt_exit == 1) {
3677 			/* Set to min rtt */
3678 			rack_set_prtt_target(rack, segsiz,
3679 					     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt));
3680 		} else if (rack_probertt_use_min_rtt_exit == 2) {
3681 			/* Set to current gp rtt */
3682 			rack_set_prtt_target(rack, segsiz,
3683 					     rack->r_ctl.rc_gp_srtt);
3684 		} else if (rack_probertt_use_min_rtt_exit == 3) {
3685 			/* Set to entry gp rtt */
3686 			rack_set_prtt_target(rack, segsiz,
3687 					     rack->r_ctl.rc_entry_gp_rtt);
3688 		} else {
3689 			uint64_t sum;
3690 			uint32_t setval;
3691 
3692 			sum = rack->r_ctl.rc_entry_gp_rtt;
3693 			sum *= 10;
3694 			sum /= (uint64_t)(max(1, rack->r_ctl.rc_gp_srtt));
3695 			if (sum >= 20) {
3696 				/*
3697 				 * A highly buffered path needs
3698 				 * cwnd space for timely to work.
3699 				 * Lets set things up as if
3700 				 * we are heading back here again.
3701 				 */
3702 				setval = rack->r_ctl.rc_entry_gp_rtt;
3703 			} else if (sum >= 15) {
3704 				/*
3705 				 * Lets take the smaller of the
3706 				 * two since we are just somewhat
3707 				 * buffered.
3708 				 */
3709 				setval = rack->r_ctl.rc_gp_srtt;
3710 				if (setval > rack->r_ctl.rc_entry_gp_rtt)
3711 					setval = rack->r_ctl.rc_entry_gp_rtt;
3712 			} else {
3713 				/*
3714 				 * Here we are not highly buffered
3715 				 * and should pick the min we can to
3716 				 * keep from causing loss.
3717 				 */
3718 				setval = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
3719 			}
3720 			rack_set_prtt_target(rack, segsiz,
3721 					     setval);
3722 		}
3723 		if (rack_probe_rtt_sets_cwnd > 1) {
3724 			/* There is a percentage here to boost */
3725 			ebdp = rack->r_ctl.rc_target_probertt_flight;
3726 			ebdp *= rack_probe_rtt_sets_cwnd;
3727 			ebdp /= 100;
3728 			setto = rack->r_ctl.rc_target_probertt_flight + ebdp;
3729 		} else
3730 			setto = rack->r_ctl.rc_target_probertt_flight;
3731 		rack->rc_tp->snd_cwnd = roundup(setto, segsiz);
3732 		if (rack->rc_tp->snd_cwnd < (segsiz * rack_timely_min_segs)) {
3733 			/* Enforce a min */
3734 			rack->rc_tp->snd_cwnd = segsiz * rack_timely_min_segs;
3735 		}
3736 		/* If we set in the cwnd also set the ssthresh point so we are in CA */
3737 		rack->rc_tp->snd_ssthresh = (rack->rc_tp->snd_cwnd - 1);
3738 	}
3739 	rack_log_rtt_shrinks(rack,  us_cts,
3740 			     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3741 			     __LINE__, RACK_RTTS_EXITPROBE);
3742 	/* Clear times last so log has all the info */
3743 	rack->r_ctl.rc_probertt_sndmax_atexit = rack->rc_tp->snd_max;
3744 	rack->r_ctl.rc_time_probertt_entered = us_cts;
3745 	rack->r_ctl.rc_time_probertt_starts = rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
3746 	rack->r_ctl.rc_time_of_last_probertt = us_cts;
3747 }
3748 
3749 static void
3750 rack_check_probe_rtt(struct tcp_rack *rack, uint32_t us_cts)
3751 {
3752 	/* Check in on probe-rtt */
3753 	if (rack->rc_gp_filled == 0) {
3754 		/* We do not do p-rtt unless we have gp measurements */
3755 		return;
3756 	}
3757 	if (rack->in_probe_rtt) {
3758 		uint64_t no_overflow;
3759 		uint32_t endtime, must_stay;
3760 
3761 		if (rack->r_ctl.rc_went_idle_time &&
3762 		    ((us_cts - rack->r_ctl.rc_went_idle_time) > rack_min_probertt_hold)) {
3763 			/*
3764 			 * We went idle during prtt, just exit now.
3765 			 */
3766 			rack_exit_probertt(rack, us_cts);
3767 		} else if (rack_probe_rtt_safety_val &&
3768 		    TSTMP_GT(us_cts, rack->r_ctl.rc_time_probertt_entered) &&
3769 		    ((us_cts - rack->r_ctl.rc_time_probertt_entered) > rack_probe_rtt_safety_val)) {
3770 			/*
3771 			 * Probe RTT safety value triggered!
3772 			 */
3773 			rack_log_rtt_shrinks(rack,  us_cts,
3774 					     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3775 					     __LINE__, RACK_RTTS_SAFETY);
3776 			rack_exit_probertt(rack, us_cts);
3777 		}
3778 		/* Calculate the max we will wait */
3779 		endtime = rack->r_ctl.rc_time_probertt_entered + (rack->r_ctl.rc_gp_srtt * rack_max_drain_wait);
3780 		if (rack->rc_highly_buffered)
3781 			endtime += (rack->r_ctl.rc_gp_srtt * rack_max_drain_hbp);
3782 		/* Calculate the min we must wait */
3783 		must_stay = rack->r_ctl.rc_time_probertt_entered + (rack->r_ctl.rc_gp_srtt * rack_must_drain);
3784 		if ((ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) > rack->r_ctl.rc_target_probertt_flight) &&
3785 		    TSTMP_LT(us_cts, endtime)) {
3786 			uint32_t calc;
3787 			/* Do we lower more? */
3788 no_exit:
3789 			if (TSTMP_GT(us_cts, rack->r_ctl.rc_time_probertt_entered))
3790 				calc = us_cts - rack->r_ctl.rc_time_probertt_entered;
3791 			else
3792 				calc = 0;
3793 			calc /= max(rack->r_ctl.rc_gp_srtt, 1);
3794 			if (calc) {
3795 				/* Maybe */
3796 				calc *= rack_per_of_gp_probertt_reduce;
3797 				rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt - calc;
3798 				/* Limit it too */
3799 				if (rack->r_ctl.rack_per_of_gp_probertt < rack_per_of_gp_lowthresh)
3800 					rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_lowthresh;
3801 			}
3802 			/* We must reach target or the time set */
3803 			return;
3804 		}
3805 		if (rack->r_ctl.rc_time_probertt_starts == 0) {
3806 			if ((TSTMP_LT(us_cts, must_stay) &&
3807 			     rack->rc_highly_buffered) ||
3808 			     (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) >
3809 			      rack->r_ctl.rc_target_probertt_flight)) {
3810 				/* We are not past the must_stay time */
3811 				goto no_exit;
3812 			}
3813 			rack_log_rtt_shrinks(rack,  us_cts,
3814 					     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3815 					     __LINE__, RACK_RTTS_REACHTARGET);
3816 			rack->r_ctl.rc_time_probertt_starts = us_cts;
3817 			if (rack->r_ctl.rc_time_probertt_starts == 0)
3818 				rack->r_ctl.rc_time_probertt_starts = 1;
3819 			/* Restore back to our rate we want to pace at in prtt */
3820 			rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt;
3821 		}
3822 		/*
3823 		 * Setup our end time, some number of gp_srtts plus 200ms.
3824 		 */
3825 		no_overflow = ((uint64_t)rack->r_ctl.rc_gp_srtt *
3826 			       (uint64_t)rack_probertt_gpsrtt_cnt_mul);
3827 		if (rack_probertt_gpsrtt_cnt_div)
3828 			endtime = (uint32_t)(no_overflow / (uint64_t)rack_probertt_gpsrtt_cnt_div);
3829 		else
3830 			endtime = 0;
3831 		endtime += rack_min_probertt_hold;
3832 		endtime += rack->r_ctl.rc_time_probertt_starts;
3833 		if (TSTMP_GEQ(us_cts,  endtime)) {
3834 			/* yes, exit probertt */
3835 			rack_exit_probertt(rack, us_cts);
3836 		}
3837 
3838 	} else if ((us_cts - rack->r_ctl.rc_lower_rtt_us_cts) >= rack_time_between_probertt) {
3839 		/* Go into probertt, its been too long since we went lower */
3840 		rack_enter_probertt(rack, us_cts);
3841 	}
3842 }
3843 
3844 static void
3845 rack_update_multiplier(struct tcp_rack *rack, int32_t timely_says, uint64_t last_bw_est,
3846 		       uint32_t rtt, int32_t rtt_diff)
3847 {
3848 	uint64_t cur_bw, up_bnd, low_bnd, subfr;
3849 	uint32_t losses;
3850 
3851 	if ((rack->rc_gp_dyn_mul == 0) ||
3852 	    (rack->use_fixed_rate) ||
3853 	    (rack->in_probe_rtt) ||
3854 	    (rack->rc_always_pace == 0)) {
3855 		/* No dynamic GP multiplier in play */
3856 		return;
3857 	}
3858 	losses = rack->r_ctl.rc_loss_count - rack->r_ctl.rc_loss_at_start;
3859 	cur_bw = rack_get_bw(rack);
3860 	/* Calculate our up and down range */
3861 	up_bnd = rack->r_ctl.last_gp_comp_bw * (uint64_t)rack_gp_per_bw_mul_up;
3862 	up_bnd /= 100;
3863 	up_bnd += rack->r_ctl.last_gp_comp_bw;
3864 
3865 	subfr = (uint64_t)rack->r_ctl.last_gp_comp_bw * (uint64_t)rack_gp_per_bw_mul_down;
3866 	subfr /= 100;
3867 	low_bnd = rack->r_ctl.last_gp_comp_bw - subfr;
3868 	if ((timely_says == 2) && (rack->r_ctl.rc_no_push_at_mrtt)) {
3869 		/*
3870 		 * This is the case where our RTT is above
3871 		 * the max target and we have been configured
3872 		 * to just do timely no bonus up stuff in that case.
3873 		 *
3874 		 * There are two configurations, set to 1, and we
3875 		 * just do timely if we are over our max. If its
3876 		 * set above 1 then we slam the multipliers down
3877 		 * to 100 and then decrement per timely.
3878 		 */
3879 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
3880 				__LINE__, 3);
3881 		if (rack->r_ctl.rc_no_push_at_mrtt > 1)
3882 			rack_validate_multipliers_at_or_below_100(rack);
3883 		rack_decrease_bw_mul(rack, timely_says, rtt, rtt_diff);
3884 	} else if ((last_bw_est < low_bnd) && !losses) {
3885 		/*
3886 		 * We are decreasing this is a bit complicated this
3887 		 * means we are loosing ground. This could be
3888 		 * because another flow entered and we are competing
3889 		 * for b/w with it. This will push the RTT up which
3890 		 * makes timely unusable unless we want to get shoved
3891 		 * into a corner and just be backed off (the age
3892 		 * old problem with delay based CC).
3893 		 *
3894 		 * On the other hand if it was a route change we
3895 		 * would like to stay somewhat contained and not
3896 		 * blow out the buffers.
3897 		 */
3898 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
3899 				__LINE__, 3);
3900 		rack->r_ctl.last_gp_comp_bw = cur_bw;
3901 		if (rack->rc_gp_bwred == 0) {
3902 			/* Go into reduction counting */
3903 			rack->rc_gp_bwred = 1;
3904 			rack->rc_gp_timely_dec_cnt = 0;
3905 		}
3906 		if ((rack->rc_gp_timely_dec_cnt < rack_timely_max_push_drop) ||
3907 		    (timely_says == 0)) {
3908 			/*
3909 			 * Push another time with a faster pacing
3910 			 * to try to gain back (we include override to
3911 			 * get a full raise factor).
3912 			 */
3913 			if ((rack->rc_gp_saw_ca && rack->r_ctl.rack_per_of_gp_ca <= rack_down_raise_thresh) ||
3914 			    (rack->rc_gp_saw_ss && rack->r_ctl.rack_per_of_gp_ss <= rack_down_raise_thresh) ||
3915 			    (timely_says == 0) ||
3916 			    (rack_down_raise_thresh == 0)) {
3917 				/*
3918 				 * Do an override up in b/w if we were
3919 				 * below the threshold or if the threshold
3920 				 * is zero we always do the raise.
3921 				 */
3922 				rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 1);
3923 			} else {
3924 				/* Log it stays the same */
3925 				rack_log_timely(rack,  0, last_bw_est, low_bnd, 0,
3926 						__LINE__, 11);
3927 			}
3928 			rack->rc_gp_timely_dec_cnt++;
3929 			/* We are not incrementing really no-count */
3930 			rack->rc_gp_incr = 0;
3931 			rack->rc_gp_timely_inc_cnt = 0;
3932 		} else {
3933 			/*
3934 			 * Lets just use the RTT
3935 			 * information and give up
3936 			 * pushing.
3937 			 */
3938 			goto use_timely;
3939 		}
3940 	} else if ((timely_says != 2) &&
3941 		    !losses &&
3942 		    (last_bw_est > up_bnd)) {
3943 		/*
3944 		 * We are increasing b/w lets keep going, updating
3945 		 * our b/w and ignoring any timely input, unless
3946 		 * of course we are at our max raise (if there is one).
3947 		 */
3948 
3949 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
3950 				__LINE__, 3);
3951 		rack->r_ctl.last_gp_comp_bw = cur_bw;
3952 		if (rack->rc_gp_saw_ss &&
3953 		    rack_per_upper_bound_ss &&
3954 		     (rack->r_ctl.rack_per_of_gp_ss == rack_per_upper_bound_ss)) {
3955 			    /*
3956 			     * In cases where we can't go higher
3957 			     * we should just use timely.
3958 			     */
3959 			    goto use_timely;
3960 		}
3961 		if (rack->rc_gp_saw_ca &&
3962 		    rack_per_upper_bound_ca &&
3963 		    (rack->r_ctl.rack_per_of_gp_ca == rack_per_upper_bound_ca)) {
3964 			    /*
3965 			     * In cases where we can't go higher
3966 			     * we should just use timely.
3967 			     */
3968 			    goto use_timely;
3969 		}
3970 		rack->rc_gp_bwred = 0;
3971 		rack->rc_gp_timely_dec_cnt = 0;
3972 		/* You get a set number of pushes if timely is trying to reduce */
3973 		if ((rack->rc_gp_incr < rack_timely_max_push_rise) || (timely_says == 0)) {
3974 			rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 0);
3975 		} else {
3976 			/* Log it stays the same */
3977 			rack_log_timely(rack,  0, last_bw_est, up_bnd, 0,
3978 			    __LINE__, 12);
3979 		}
3980 		return;
3981 	} else {
3982 		/*
3983 		 * We are staying between the lower and upper range bounds
3984 		 * so use timely to decide.
3985 		 */
3986 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
3987 				__LINE__, 3);
3988 use_timely:
3989 		if (timely_says) {
3990 			rack->rc_gp_incr = 0;
3991 			rack->rc_gp_timely_inc_cnt = 0;
3992 			if ((rack->rc_gp_timely_dec_cnt < rack_timely_max_push_drop) &&
3993 			    !losses &&
3994 			    (last_bw_est < low_bnd)) {
3995 				/* We are loosing ground */
3996 				rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 0);
3997 				rack->rc_gp_timely_dec_cnt++;
3998 				/* We are not incrementing really no-count */
3999 				rack->rc_gp_incr = 0;
4000 				rack->rc_gp_timely_inc_cnt = 0;
4001 			} else
4002 				rack_decrease_bw_mul(rack, timely_says, rtt, rtt_diff);
4003 		} else {
4004 			rack->rc_gp_bwred = 0;
4005 			rack->rc_gp_timely_dec_cnt = 0;
4006 			rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 0);
4007 		}
4008 	}
4009 }
4010 
4011 static int32_t
4012 rack_make_timely_judgement(struct tcp_rack *rack, uint32_t rtt, int32_t rtt_diff, uint32_t prev_rtt)
4013 {
4014 	int32_t timely_says;
4015 	uint64_t log_mult, log_rtt_a_diff;
4016 
4017 	log_rtt_a_diff = rtt;
4018 	log_rtt_a_diff <<= 32;
4019 	log_rtt_a_diff |= (uint32_t)rtt_diff;
4020 	if (rtt >= (get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) *
4021 		    rack_gp_rtt_maxmul)) {
4022 		/* Reduce the b/w multiplier */
4023 		timely_says = 2;
4024 		log_mult = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_maxmul;
4025 		log_mult <<= 32;
4026 		log_mult |= prev_rtt;
4027 		rack_log_timely(rack,  timely_says, log_mult,
4028 				get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
4029 				log_rtt_a_diff, __LINE__, 4);
4030 	} else if (rtt <= (get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) +
4031 			   ((get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_minmul) /
4032 			    max(rack_gp_rtt_mindiv , 1)))) {
4033 		/* Increase the b/w multiplier */
4034 		log_mult = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) +
4035 			((get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_minmul) /
4036 			 max(rack_gp_rtt_mindiv , 1));
4037 		log_mult <<= 32;
4038 		log_mult |= prev_rtt;
4039 		timely_says = 0;
4040 		rack_log_timely(rack,  timely_says, log_mult ,
4041 				get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
4042 				log_rtt_a_diff, __LINE__, 5);
4043 	} else {
4044 		/*
4045 		 * Use a gradient to find it the timely gradient
4046 		 * is:
4047 		 * grad = rc_rtt_diff / min_rtt;
4048 		 *
4049 		 * anything below or equal to 0 will be
4050 		 * a increase indication. Anything above
4051 		 * zero is a decrease. Note we take care
4052 		 * of the actual gradient calculation
4053 		 * in the reduction (its not needed for
4054 		 * increase).
4055 		 */
4056 		log_mult = prev_rtt;
4057 		if (rtt_diff <= 0) {
4058 			/*
4059 			 * Rttdiff is less than zero, increase the
4060 			 * b/w multiplier (its 0 or negative)
4061 			 */
4062 			timely_says = 0;
4063 			rack_log_timely(rack,  timely_says, log_mult,
4064 					get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt), log_rtt_a_diff, __LINE__, 6);
4065 		} else {
4066 			/* Reduce the b/w multiplier */
4067 			timely_says = 1;
4068 			rack_log_timely(rack,  timely_says, log_mult,
4069 					get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt), log_rtt_a_diff, __LINE__, 7);
4070 		}
4071 	}
4072 	return (timely_says);
4073 }
4074 
4075 static void
4076 rack_do_goodput_measurement(struct tcpcb *tp, struct tcp_rack *rack,
4077 			    tcp_seq th_ack, int line, uint8_t quality)
4078 {
4079 	uint64_t tim, bytes_ps, ltim, stim, utim;
4080 	uint32_t segsiz, bytes, reqbytes, us_cts;
4081 	int32_t gput, new_rtt_diff, timely_says;
4082 	uint64_t  resid_bw, subpart = 0, addpart = 0, srtt;
4083 	int did_add = 0;
4084 
4085 	us_cts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
4086 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
4087 	if (TSTMP_GEQ(us_cts, tp->gput_ts))
4088 		tim = us_cts - tp->gput_ts;
4089 	else
4090 		tim = 0;
4091 	if (rack->r_ctl.rc_gp_cumack_ts > rack->r_ctl.rc_gp_output_ts)
4092 		stim = rack->r_ctl.rc_gp_cumack_ts - rack->r_ctl.rc_gp_output_ts;
4093 	else
4094 		stim = 0;
4095 	/*
4096 	 * Use the larger of the send time or ack time. This prevents us
4097 	 * from being influenced by ack artifacts to come up with too
4098 	 * high of measurement. Note that since we are spanning over many more
4099 	 * bytes in most of our measurements hopefully that is less likely to
4100 	 * occur.
4101 	 */
4102 	if (tim > stim)
4103 		utim = max(tim, 1);
4104 	else
4105 		utim = max(stim, 1);
4106 	/* Lets get a msec time ltim too for the old stuff */
4107 	ltim = max(1, (utim / HPTS_USEC_IN_MSEC));
4108 	gput = (((uint64_t) (th_ack - tp->gput_seq)) << 3) / ltim;
4109 	reqbytes = min(rc_init_window(rack), (MIN_GP_WIN * segsiz));
4110 	if ((tim == 0) && (stim == 0)) {
4111 		/*
4112 		 * Invalid measurement time, maybe
4113 		 * all on one ack/one send?
4114 		 */
4115 		bytes = 0;
4116 		bytes_ps = 0;
4117 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
4118 					   0, 0, 0, 10, __LINE__, NULL, quality);
4119 		goto skip_measurement;
4120 	}
4121 	if (rack->r_ctl.rc_gp_lowrtt == 0xffffffff) {
4122 		/* We never made a us_rtt measurement? */
4123 		bytes = 0;
4124 		bytes_ps = 0;
4125 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
4126 					   0, 0, 0, 10, __LINE__, NULL, quality);
4127 		goto skip_measurement;
4128 	}
4129 	/*
4130 	 * Calculate the maximum possible b/w this connection
4131 	 * could have. We base our calculation on the lowest
4132 	 * rtt we have seen during the measurement and the
4133 	 * largest rwnd the client has given us in that time. This
4134 	 * forms a BDP that is the maximum that we could ever
4135 	 * get to the client. Anything larger is not valid.
4136 	 *
4137 	 * I originally had code here that rejected measurements
4138 	 * where the time was less than 1/2 the latest us_rtt.
4139 	 * But after thinking on that I realized its wrong since
4140 	 * say you had a 150Mbps or even 1Gbps link, and you
4141 	 * were a long way away.. example I am in Europe (100ms rtt)
4142 	 * talking to my 1Gbps link in S.C. Now measuring say 150,000
4143 	 * bytes my time would be 1.2ms, and yet my rtt would say
4144 	 * the measurement was invalid the time was < 50ms. The
4145 	 * same thing is true for 150Mb (8ms of time).
4146 	 *
4147 	 * A better way I realized is to look at what the maximum
4148 	 * the connection could possibly do. This is gated on
4149 	 * the lowest RTT we have seen and the highest rwnd.
4150 	 * We should in theory never exceed that, if we are
4151 	 * then something on the path is storing up packets
4152 	 * and then feeding them all at once to our endpoint
4153 	 * messing up our measurement.
4154 	 */
4155 	rack->r_ctl.last_max_bw = rack->r_ctl.rc_gp_high_rwnd;
4156 	rack->r_ctl.last_max_bw *= HPTS_USEC_IN_SEC;
4157 	rack->r_ctl.last_max_bw /= rack->r_ctl.rc_gp_lowrtt;
4158 	if (SEQ_LT(th_ack, tp->gput_seq)) {
4159 		/* No measurement can be made */
4160 		bytes = 0;
4161 		bytes_ps = 0;
4162 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
4163 					   0, 0, 0, 10, __LINE__, NULL, quality);
4164 		goto skip_measurement;
4165 	} else
4166 		bytes = (th_ack - tp->gput_seq);
4167 	bytes_ps = (uint64_t)bytes;
4168 	/*
4169 	 * Don't measure a b/w for pacing unless we have gotten at least
4170 	 * an initial windows worth of data in this measurement interval.
4171 	 *
4172 	 * Small numbers of bytes get badly influenced by delayed ack and
4173 	 * other artifacts. Note we take the initial window or our
4174 	 * defined minimum GP (defaulting to 10 which hopefully is the
4175 	 * IW).
4176 	 */
4177 	if (rack->rc_gp_filled == 0) {
4178 		/*
4179 		 * The initial estimate is special. We
4180 		 * have blasted out an IW worth of packets
4181 		 * without a real valid ack ts results. We
4182 		 * then setup the app_limited_needs_set flag,
4183 		 * this should get the first ack in (probably 2
4184 		 * MSS worth) to be recorded as the timestamp.
4185 		 * We thus allow a smaller number of bytes i.e.
4186 		 * IW - 2MSS.
4187 		 */
4188 		reqbytes -= (2 * segsiz);
4189 		/* Also lets fill previous for our first measurement to be neutral */
4190 		rack->r_ctl.rc_prev_gp_srtt = rack->r_ctl.rc_gp_srtt;
4191 	}
4192 	if ((bytes_ps < reqbytes) || rack->app_limited_needs_set) {
4193 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
4194 					   rack->r_ctl.rc_app_limited_cnt,
4195 					   0, 0, 10, __LINE__, NULL, quality);
4196 		goto skip_measurement;
4197 	}
4198 	/*
4199 	 * We now need to calculate the Timely like status so
4200 	 * we can update (possibly) the b/w multipliers.
4201 	 */
4202 	new_rtt_diff = (int32_t)rack->r_ctl.rc_gp_srtt - (int32_t)rack->r_ctl.rc_prev_gp_srtt;
4203 	if (rack->rc_gp_filled == 0) {
4204 		/* No previous reading */
4205 		rack->r_ctl.rc_rtt_diff = new_rtt_diff;
4206 	} else {
4207 		if (rack->measure_saw_probe_rtt == 0) {
4208 			/*
4209 			 * We don't want a probertt to be counted
4210 			 * since it will be negative incorrectly. We
4211 			 * expect to be reducing the RTT when we
4212 			 * pace at a slower rate.
4213 			 */
4214 			rack->r_ctl.rc_rtt_diff -= (rack->r_ctl.rc_rtt_diff / 8);
4215 			rack->r_ctl.rc_rtt_diff += (new_rtt_diff / 8);
4216 		}
4217 	}
4218 	timely_says = rack_make_timely_judgement(rack,
4219 		rack->r_ctl.rc_gp_srtt,
4220 		rack->r_ctl.rc_rtt_diff,
4221 	        rack->r_ctl.rc_prev_gp_srtt
4222 		);
4223 	bytes_ps *= HPTS_USEC_IN_SEC;
4224 	bytes_ps /= utim;
4225 	if (bytes_ps > rack->r_ctl.last_max_bw) {
4226 		/*
4227 		 * Something is on path playing
4228 		 * since this b/w is not possible based
4229 		 * on our BDP (highest rwnd and lowest rtt
4230 		 * we saw in the measurement window).
4231 		 *
4232 		 * Another option here would be to
4233 		 * instead skip the measurement.
4234 		 */
4235 		rack_log_pacing_delay_calc(rack, bytes, reqbytes,
4236 					   bytes_ps, rack->r_ctl.last_max_bw, 0,
4237 					   11, __LINE__, NULL, quality);
4238 		bytes_ps = rack->r_ctl.last_max_bw;
4239 	}
4240 	/* We store gp for b/w in bytes per second */
4241 	if (rack->rc_gp_filled == 0) {
4242 		/* Initial measurement */
4243 		if (bytes_ps) {
4244 			rack->r_ctl.gp_bw = bytes_ps;
4245 			rack->rc_gp_filled = 1;
4246 			rack->r_ctl.num_measurements = 1;
4247 			rack_set_pace_segments(rack->rc_tp, rack, __LINE__, NULL);
4248 		} else {
4249 			rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
4250 						   rack->r_ctl.rc_app_limited_cnt,
4251 						   0, 0, 10, __LINE__, NULL, quality);
4252 		}
4253 		if (tcp_in_hpts(rack->rc_inp) &&
4254 		    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
4255 			/*
4256 			 * Ok we can't trust the pacer in this case
4257 			 * where we transition from un-paced to paced.
4258 			 * Or for that matter when the burst mitigation
4259 			 * was making a wild guess and got it wrong.
4260 			 * Stop the pacer and clear up all the aggregate
4261 			 * delays etc.
4262 			 */
4263 			tcp_hpts_remove(rack->rc_inp);
4264 			rack->r_ctl.rc_hpts_flags = 0;
4265 			rack->r_ctl.rc_last_output_to = 0;
4266 		}
4267 		did_add = 2;
4268 	} else if (rack->r_ctl.num_measurements < RACK_REQ_AVG) {
4269 		/* Still a small number run an average */
4270 		rack->r_ctl.gp_bw += bytes_ps;
4271 		addpart = rack->r_ctl.num_measurements;
4272 		rack->r_ctl.num_measurements++;
4273 		if (rack->r_ctl.num_measurements >= RACK_REQ_AVG) {
4274 			/* We have collected enough to move forward */
4275 			rack->r_ctl.gp_bw /= (uint64_t)rack->r_ctl.num_measurements;
4276 		}
4277 		did_add = 3;
4278 	} else {
4279 		/*
4280 		 * We want to take 1/wma of the goodput and add in to 7/8th
4281 		 * of the old value weighted by the srtt. So if your measurement
4282 		 * period is say 2 SRTT's long you would get 1/4 as the
4283 		 * value, if it was like 1/2 SRTT then you would get 1/16th.
4284 		 *
4285 		 * But we must be careful not to take too much i.e. if the
4286 		 * srtt is say 20ms and the measurement is taken over
4287 		 * 400ms our weight would be 400/20 i.e. 20. On the
4288 		 * other hand if we get a measurement over 1ms with a
4289 		 * 10ms rtt we only want to take a much smaller portion.
4290 		 */
4291 		if (rack->r_ctl.num_measurements < 0xff) {
4292 			rack->r_ctl.num_measurements++;
4293 		}
4294 		srtt = (uint64_t)tp->t_srtt;
4295 		if (srtt == 0) {
4296 			/*
4297 			 * Strange why did t_srtt go back to zero?
4298 			 */
4299 			if (rack->r_ctl.rc_rack_min_rtt)
4300 				srtt = rack->r_ctl.rc_rack_min_rtt;
4301 			else
4302 				srtt = HPTS_USEC_IN_MSEC;
4303 		}
4304 		/*
4305 		 * XXXrrs: Note for reviewers, in playing with
4306 		 * dynamic pacing I discovered this GP calculation
4307 		 * as done originally leads to some undesired results.
4308 		 * Basically you can get longer measurements contributing
4309 		 * too much to the WMA. Thus I changed it if you are doing
4310 		 * dynamic adjustments to only do the aportioned adjustment
4311 		 * if we have a very small (time wise) measurement. Longer
4312 		 * measurements just get there weight (defaulting to 1/8)
4313 		 * add to the WMA. We may want to think about changing
4314 		 * this to always do that for both sides i.e. dynamic
4315 		 * and non-dynamic... but considering lots of folks
4316 		 * were playing with this I did not want to change the
4317 		 * calculation per.se. without your thoughts.. Lawerence?
4318 		 * Peter??
4319 		 */
4320 		if (rack->rc_gp_dyn_mul == 0) {
4321 			subpart = rack->r_ctl.gp_bw * utim;
4322 			subpart /= (srtt * 8);
4323 			if (subpart < (rack->r_ctl.gp_bw / 2)) {
4324 				/*
4325 				 * The b/w update takes no more
4326 				 * away then 1/2 our running total
4327 				 * so factor it in.
4328 				 */
4329 				addpart = bytes_ps * utim;
4330 				addpart /= (srtt * 8);
4331 			} else {
4332 				/*
4333 				 * Don't allow a single measurement
4334 				 * to account for more than 1/2 of the
4335 				 * WMA. This could happen on a retransmission
4336 				 * where utim becomes huge compared to
4337 				 * srtt (multiple retransmissions when using
4338 				 * the sending rate which factors in all the
4339 				 * transmissions from the first one).
4340 				 */
4341 				subpart = rack->r_ctl.gp_bw / 2;
4342 				addpart = bytes_ps / 2;
4343 			}
4344 			resid_bw = rack->r_ctl.gp_bw - subpart;
4345 			rack->r_ctl.gp_bw = resid_bw + addpart;
4346 			did_add = 1;
4347 		} else {
4348 			if ((utim / srtt) <= 1) {
4349 				/*
4350 				 * The b/w update was over a small period
4351 				 * of time. The idea here is to prevent a small
4352 				 * measurement time period from counting
4353 				 * too much. So we scale it based on the
4354 				 * time so it attributes less than 1/rack_wma_divisor
4355 				 * of its measurement.
4356 				 */
4357 				subpart = rack->r_ctl.gp_bw * utim;
4358 				subpart /= (srtt * rack_wma_divisor);
4359 				addpart = bytes_ps * utim;
4360 				addpart /= (srtt * rack_wma_divisor);
4361 			} else {
4362 				/*
4363 				 * The scaled measurement was long
4364 				 * enough so lets just add in the
4365 				 * portion of the measurement i.e. 1/rack_wma_divisor
4366 				 */
4367 				subpart = rack->r_ctl.gp_bw / rack_wma_divisor;
4368 				addpart = bytes_ps / rack_wma_divisor;
4369 			}
4370 			if ((rack->measure_saw_probe_rtt == 0) ||
4371 		            (bytes_ps > rack->r_ctl.gp_bw)) {
4372 				/*
4373 				 * For probe-rtt we only add it in
4374 				 * if its larger, all others we just
4375 				 * add in.
4376 				 */
4377 				did_add = 1;
4378 				resid_bw = rack->r_ctl.gp_bw - subpart;
4379 				rack->r_ctl.gp_bw = resid_bw + addpart;
4380 			}
4381 		}
4382 	}
4383 	if ((rack->gp_ready == 0) &&
4384 	    (rack->r_ctl.num_measurements >= rack->r_ctl.req_measurements)) {
4385 		/* We have enough measurements now */
4386 		rack->gp_ready = 1;
4387 		rack_set_cc_pacing(rack);
4388 		if (rack->defer_options)
4389 			rack_apply_deferred_options(rack);
4390 	}
4391 	rack_log_pacing_delay_calc(rack, subpart, addpart, bytes_ps, stim,
4392 				   rack_get_bw(rack), 22, did_add, NULL, quality);
4393 	/* We do not update any multipliers if we are in or have seen a probe-rtt */
4394 	if ((rack->measure_saw_probe_rtt == 0) && rack->rc_gp_rtt_set)
4395 		rack_update_multiplier(rack, timely_says, bytes_ps,
4396 				       rack->r_ctl.rc_gp_srtt,
4397 				       rack->r_ctl.rc_rtt_diff);
4398 	rack_log_pacing_delay_calc(rack, bytes, tim, bytes_ps, stim,
4399 				   rack_get_bw(rack), 3, line, NULL, quality);
4400 	/* reset the gp srtt and setup the new prev */
4401 	rack->r_ctl.rc_prev_gp_srtt = rack->r_ctl.rc_gp_srtt;
4402 	/* Record the lost count for the next measurement */
4403 	rack->r_ctl.rc_loss_at_start = rack->r_ctl.rc_loss_count;
4404 	/*
4405 	 * We restart our diffs based on the gpsrtt in the
4406 	 * measurement window.
4407 	 */
4408 	rack->rc_gp_rtt_set = 0;
4409 	rack->rc_gp_saw_rec = 0;
4410 	rack->rc_gp_saw_ca = 0;
4411 	rack->rc_gp_saw_ss = 0;
4412 	rack->rc_dragged_bottom = 0;
4413 skip_measurement:
4414 
4415 #ifdef STATS
4416 	stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_GPUT,
4417 				 gput);
4418 	/*
4419 	 * XXXLAS: This is a temporary hack, and should be
4420 	 * chained off VOI_TCP_GPUT when stats(9) grows an
4421 	 * API to deal with chained VOIs.
4422 	 */
4423 	if (tp->t_stats_gput_prev > 0)
4424 		stats_voi_update_abs_s32(tp->t_stats,
4425 					 VOI_TCP_GPUT_ND,
4426 					 ((gput - tp->t_stats_gput_prev) * 100) /
4427 					 tp->t_stats_gput_prev);
4428 #endif
4429 	tp->t_flags &= ~TF_GPUTINPROG;
4430 	tp->t_stats_gput_prev = gput;
4431 	/*
4432 	 * Now are we app limited now and there is space from where we
4433 	 * were to where we want to go?
4434 	 *
4435 	 * We don't do the other case i.e. non-applimited here since
4436 	 * the next send will trigger us picking up the missing data.
4437 	 */
4438 	if (rack->r_ctl.rc_first_appl &&
4439 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
4440 	    rack->r_ctl.rc_app_limited_cnt &&
4441 	    (SEQ_GT(rack->r_ctl.rc_first_appl->r_start, th_ack)) &&
4442 	    ((rack->r_ctl.rc_first_appl->r_end - th_ack) >
4443 	     max(rc_init_window(rack), (MIN_GP_WIN * segsiz)))) {
4444 		/*
4445 		 * Yep there is enough outstanding to make a measurement here.
4446 		 */
4447 		struct rack_sendmap *rsm, fe;
4448 
4449 		rack->r_ctl.rc_gp_lowrtt = 0xffffffff;
4450 		rack->r_ctl.rc_gp_high_rwnd = rack->rc_tp->snd_wnd;
4451 		tp->gput_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
4452 		rack->app_limited_needs_set = 0;
4453 		tp->gput_seq = th_ack;
4454 		if (rack->in_probe_rtt)
4455 			rack->measure_saw_probe_rtt = 1;
4456 		else if ((rack->measure_saw_probe_rtt) &&
4457 			 (SEQ_GEQ(tp->gput_seq, rack->r_ctl.rc_probertt_sndmax_atexit)))
4458 			rack->measure_saw_probe_rtt = 0;
4459 		if ((rack->r_ctl.rc_first_appl->r_end - th_ack) >= rack_get_measure_window(tp, rack)) {
4460 			/* There is a full window to gain info from */
4461 			tp->gput_ack = tp->gput_seq + rack_get_measure_window(tp, rack);
4462 		} else {
4463 			/* We can only measure up to the applimited point */
4464 			tp->gput_ack = tp->gput_seq + (rack->r_ctl.rc_first_appl->r_end - th_ack);
4465 			if ((tp->gput_ack - tp->gput_seq) < (MIN_GP_WIN * segsiz)) {
4466 				/*
4467 				 * We don't have enough to make a measurement.
4468 				 */
4469 				tp->t_flags &= ~TF_GPUTINPROG;
4470 				rack_log_pacing_delay_calc(rack, tp->gput_ack, tp->gput_seq,
4471 							   0, 0, 0, 6, __LINE__, NULL, quality);
4472 				return;
4473 			}
4474 		}
4475 		if (tp->t_state >= TCPS_FIN_WAIT_1) {
4476 			/*
4477 			 * We will get no more data into the SB
4478 			 * this means we need to have the data available
4479 			 * before we start a measurement.
4480 			 */
4481 			if (sbavail(&tptosocket(tp)->so_snd) < (tp->gput_ack - tp->gput_seq)) {
4482 				/* Nope not enough data. */
4483 				return;
4484 			}
4485 		}
4486 		tp->t_flags |= TF_GPUTINPROG;
4487 		/*
4488 		 * Now we need to find the timestamp of the send at tp->gput_seq
4489 		 * for the send based measurement.
4490 		 */
4491 		fe.r_start = tp->gput_seq;
4492 		rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
4493 		if (rsm) {
4494 			/* Ok send-based limit is set */
4495 			if (SEQ_LT(rsm->r_start, tp->gput_seq)) {
4496 				/*
4497 				 * Move back to include the earlier part
4498 				 * so our ack time lines up right (this may
4499 				 * make an overlapping measurement but thats
4500 				 * ok).
4501 				 */
4502 				tp->gput_seq = rsm->r_start;
4503 			}
4504 			if (rsm->r_flags & RACK_ACKED)
4505 				tp->gput_ts = (uint32_t)rsm->r_ack_arrival;
4506 			else
4507 				rack->app_limited_needs_set = 1;
4508 			rack->r_ctl.rc_gp_output_ts = rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
4509 		} else {
4510 			/*
4511 			 * If we don't find the rsm due to some
4512 			 * send-limit set the current time, which
4513 			 * basically disables the send-limit.
4514 			 */
4515 			struct timeval tv;
4516 
4517 			microuptime(&tv);
4518 			rack->r_ctl.rc_gp_output_ts = rack_to_usec_ts(&tv);
4519 		}
4520 		rack_log_pacing_delay_calc(rack,
4521 					   tp->gput_seq,
4522 					   tp->gput_ack,
4523 					   (uint64_t)rsm,
4524 					   tp->gput_ts,
4525 					   rack->r_ctl.rc_app_limited_cnt,
4526 					   9,
4527 					   __LINE__, NULL, quality);
4528 	}
4529 }
4530 
4531 /*
4532  * CC wrapper hook functions
4533  */
4534 static void
4535 rack_ack_received(struct tcpcb *tp, struct tcp_rack *rack, uint32_t th_ack, uint16_t nsegs,
4536     uint16_t type, int32_t recovery)
4537 {
4538 	uint32_t prior_cwnd, acked;
4539 	struct tcp_log_buffer *lgb = NULL;
4540 	uint8_t labc_to_use, quality;
4541 
4542 	INP_WLOCK_ASSERT(tptoinpcb(tp));
4543 	tp->t_ccv.nsegs = nsegs;
4544 	acked = tp->t_ccv.bytes_this_ack = (th_ack - tp->snd_una);
4545 	if ((recovery) && (rack->r_ctl.rc_early_recovery_segs)) {
4546 		uint32_t max;
4547 
4548 		max = rack->r_ctl.rc_early_recovery_segs * ctf_fixed_maxseg(tp);
4549 		if (tp->t_ccv.bytes_this_ack > max) {
4550 			tp->t_ccv.bytes_this_ack = max;
4551 		}
4552 	}
4553 #ifdef STATS
4554 	stats_voi_update_abs_s32(tp->t_stats, VOI_TCP_CALCFRWINDIFF,
4555 	    ((int32_t)rack->r_ctl.cwnd_to_use) - tp->snd_wnd);
4556 #endif
4557 	quality = RACK_QUALITY_NONE;
4558 	if ((tp->t_flags & TF_GPUTINPROG) &&
4559 	    rack_enough_for_measurement(tp, rack, th_ack, &quality)) {
4560 		/* Measure the Goodput */
4561 		rack_do_goodput_measurement(tp, rack, th_ack, __LINE__, quality);
4562 #ifdef NETFLIX_PEAKRATE
4563 		if ((type == CC_ACK) &&
4564 		    (tp->t_maxpeakrate)) {
4565 			/*
4566 			 * We update t_peakrate_thr. This gives us roughly
4567 			 * one update per round trip time. Note
4568 			 * it will only be used if pace_always is off i.e
4569 			 * we don't do this for paced flows.
4570 			 */
4571 			rack_update_peakrate_thr(tp);
4572 		}
4573 #endif
4574 	}
4575 	/* Which way our we limited, if not cwnd limited no advance in CA */
4576 	if (tp->snd_cwnd <= tp->snd_wnd)
4577 		tp->t_ccv.flags |= CCF_CWND_LIMITED;
4578 	else
4579 		tp->t_ccv.flags &= ~CCF_CWND_LIMITED;
4580 	if (tp->snd_cwnd > tp->snd_ssthresh) {
4581 		tp->t_bytes_acked += min(tp->t_ccv.bytes_this_ack,
4582 			 nsegs * V_tcp_abc_l_var * ctf_fixed_maxseg(tp));
4583 		/* For the setting of a window past use the actual scwnd we are using */
4584 		if (tp->t_bytes_acked >= rack->r_ctl.cwnd_to_use) {
4585 			tp->t_bytes_acked -= rack->r_ctl.cwnd_to_use;
4586 			tp->t_ccv.flags |= CCF_ABC_SENTAWND;
4587 		}
4588 	} else {
4589 		tp->t_ccv.flags &= ~CCF_ABC_SENTAWND;
4590 		tp->t_bytes_acked = 0;
4591 	}
4592 	prior_cwnd = tp->snd_cwnd;
4593 	if ((recovery == 0) || (rack_max_abc_post_recovery == 0) || rack->r_use_labc_for_rec ||
4594 	    (rack_client_low_buf && (rack->client_bufferlvl < rack_client_low_buf)))
4595 		labc_to_use = rack->rc_labc;
4596 	else
4597 		labc_to_use = rack_max_abc_post_recovery;
4598 	if (rack_verbose_logging && (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
4599 		union tcp_log_stackspecific log;
4600 		struct timeval tv;
4601 
4602 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
4603 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
4604 		log.u_bbr.flex1 = th_ack;
4605 		log.u_bbr.flex2 = tp->t_ccv.flags;
4606 		log.u_bbr.flex3 = tp->t_ccv.bytes_this_ack;
4607 		log.u_bbr.flex4 = tp->t_ccv.nsegs;
4608 		log.u_bbr.flex5 = labc_to_use;
4609 		log.u_bbr.flex6 = prior_cwnd;
4610 		log.u_bbr.flex7 = V_tcp_do_newsack;
4611 		log.u_bbr.flex8 = 1;
4612 		lgb = tcp_log_event_(tp, NULL, NULL, NULL, BBR_LOG_CWND, 0,
4613 				     0, &log, false, NULL, NULL, 0, &tv);
4614 	}
4615 	if (CC_ALGO(tp)->ack_received != NULL) {
4616 		/* XXXLAS: Find a way to live without this */
4617 		tp->t_ccv.curack = th_ack;
4618 		tp->t_ccv.labc = labc_to_use;
4619 		tp->t_ccv.flags |= CCF_USE_LOCAL_ABC;
4620 		CC_ALGO(tp)->ack_received(&tp->t_ccv, type);
4621 	}
4622 	if (lgb) {
4623 		lgb->tlb_stackinfo.u_bbr.flex6 = tp->snd_cwnd;
4624 	}
4625 	if (rack->r_must_retran) {
4626 		if (SEQ_GEQ(th_ack, rack->r_ctl.rc_snd_max_at_rto)) {
4627 			/*
4628 			 * We now are beyond the rxt point so lets disable
4629 			 * the flag.
4630 			 */
4631 			rack->r_ctl.rc_out_at_rto = 0;
4632 			rack->r_must_retran = 0;
4633 		} else if ((prior_cwnd + ctf_fixed_maxseg(tp)) <= tp->snd_cwnd) {
4634 			/*
4635 			 * Only decrement the rc_out_at_rto if the cwnd advances
4636 			 * at least a whole segment. Otherwise next time the peer
4637 			 * acks, we won't be able to send this generaly happens
4638 			 * when we are in Congestion Avoidance.
4639 			 */
4640 			if (acked <= rack->r_ctl.rc_out_at_rto){
4641 				rack->r_ctl.rc_out_at_rto -= acked;
4642 			} else {
4643 				rack->r_ctl.rc_out_at_rto = 0;
4644 			}
4645 		}
4646 	}
4647 #ifdef STATS
4648 	stats_voi_update_abs_ulong(tp->t_stats, VOI_TCP_LCWIN, rack->r_ctl.cwnd_to_use);
4649 #endif
4650 	if (rack->r_ctl.rc_rack_largest_cwnd < rack->r_ctl.cwnd_to_use) {
4651 		rack->r_ctl.rc_rack_largest_cwnd = rack->r_ctl.cwnd_to_use;
4652 	}
4653 #ifdef NETFLIX_PEAKRATE
4654 	/* we enforce max peak rate if it is set and we are not pacing */
4655 	if ((rack->rc_always_pace == 0) &&
4656 	    tp->t_peakrate_thr &&
4657 	    (tp->snd_cwnd > tp->t_peakrate_thr)) {
4658 		tp->snd_cwnd = tp->t_peakrate_thr;
4659 	}
4660 #endif
4661 }
4662 
4663 static void
4664 tcp_rack_partialack(struct tcpcb *tp)
4665 {
4666 	struct tcp_rack *rack;
4667 
4668 	rack = (struct tcp_rack *)tp->t_fb_ptr;
4669 	INP_WLOCK_ASSERT(tptoinpcb(tp));
4670 	/*
4671 	 * If we are doing PRR and have enough
4672 	 * room to send <or> we are pacing and prr
4673 	 * is disabled we will want to see if we
4674 	 * can send data (by setting r_wanted_output to
4675 	 * true).
4676 	 */
4677 	if ((rack->r_ctl.rc_prr_sndcnt > 0) ||
4678 	    rack->rack_no_prr)
4679 		rack->r_wanted_output = 1;
4680 }
4681 
4682 static void
4683 rack_post_recovery(struct tcpcb *tp, uint32_t th_ack)
4684 {
4685 	struct tcp_rack *rack;
4686 	uint32_t orig_cwnd;
4687 
4688 	orig_cwnd = tp->snd_cwnd;
4689 	INP_WLOCK_ASSERT(tptoinpcb(tp));
4690 	rack = (struct tcp_rack *)tp->t_fb_ptr;
4691 	/* only alert CC if we alerted when we entered */
4692 	if (CC_ALGO(tp)->post_recovery != NULL) {
4693 		tp->t_ccv.curack = th_ack;
4694 		CC_ALGO(tp)->post_recovery(&tp->t_ccv);
4695 		if (tp->snd_cwnd < tp->snd_ssthresh) {
4696 			/*
4697 			 * Rack has burst control and pacing
4698 			 * so lets not set this any lower than
4699 			 * snd_ssthresh per RFC-6582 (option 2).
4700 			 */
4701 			tp->snd_cwnd = tp->snd_ssthresh;
4702 		}
4703 	}
4704 	if (rack_verbose_logging && (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
4705 		union tcp_log_stackspecific log;
4706 		struct timeval tv;
4707 
4708 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
4709 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
4710 		log.u_bbr.flex1 = th_ack;
4711 		log.u_bbr.flex2 = tp->t_ccv.flags;
4712 		log.u_bbr.flex3 = tp->t_ccv.bytes_this_ack;
4713 		log.u_bbr.flex4 = tp->t_ccv.nsegs;
4714 		log.u_bbr.flex5 = V_tcp_abc_l_var;
4715 		log.u_bbr.flex6 = orig_cwnd;
4716 		log.u_bbr.flex7 = V_tcp_do_newsack;
4717 		log.u_bbr.pkts_out = rack->r_ctl.rc_prr_sndcnt;
4718 		log.u_bbr.flex8 = 2;
4719 		tcp_log_event_(tp, NULL, NULL, NULL, BBR_LOG_CWND, 0,
4720 			       0, &log, false, NULL, NULL, 0, &tv);
4721 	}
4722 	if ((rack->rack_no_prr == 0) &&
4723 	    (rack->no_prr_addback == 0) &&
4724 	    (rack->r_ctl.rc_prr_sndcnt > 0)) {
4725 		/*
4726 		 * Suck the next prr cnt back into cwnd, but
4727 		 * only do that if we are not application limited.
4728 		 */
4729 		if (ctf_outstanding(tp) <= sbavail(&tptosocket(tp)->so_snd)) {
4730 			/*
4731 			 * We are allowed to add back to the cwnd the amount we did
4732 			 * not get out if:
4733 			 * a) no_prr_addback is off.
4734 			 * b) we are not app limited
4735 			 * c) we are doing prr
4736 			 * <and>
4737 			 * d) it is bounded by rack_prr_addbackmax (if addback is 0, then none).
4738 			 */
4739 			tp->snd_cwnd += min((ctf_fixed_maxseg(tp) * rack_prr_addbackmax),
4740 					    rack->r_ctl.rc_prr_sndcnt);
4741 		}
4742 		rack->r_ctl.rc_prr_sndcnt = 0;
4743 		rack_log_to_prr(rack, 1, 0, __LINE__);
4744 	}
4745 	rack_log_to_prr(rack, 14, orig_cwnd, __LINE__);
4746 	tp->snd_recover = tp->snd_una;
4747 	if (rack->r_ctl.dsack_persist) {
4748 		rack->r_ctl.dsack_persist--;
4749 		if (rack->r_ctl.num_dsack && (rack->r_ctl.dsack_persist == 0)) {
4750 			rack->r_ctl.num_dsack = 0;
4751 		}
4752 		rack_log_dsack_event(rack, 1, __LINE__, 0, 0);
4753 	}
4754 	EXIT_RECOVERY(tp->t_flags);
4755 }
4756 
4757 static void
4758 rack_cong_signal(struct tcpcb *tp, uint32_t type, uint32_t ack, int line)
4759 {
4760 	struct tcp_rack *rack;
4761 	uint32_t ssthresh_enter, cwnd_enter, in_rec_at_entry, orig_cwnd;
4762 
4763 	INP_WLOCK_ASSERT(tptoinpcb(tp));
4764 #ifdef STATS
4765 	stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_CSIG, type);
4766 #endif
4767 	if (IN_RECOVERY(tp->t_flags) == 0) {
4768 		in_rec_at_entry = 0;
4769 		ssthresh_enter = tp->snd_ssthresh;
4770 		cwnd_enter = tp->snd_cwnd;
4771 	} else
4772 		in_rec_at_entry = 1;
4773 	rack = (struct tcp_rack *)tp->t_fb_ptr;
4774 	switch (type) {
4775 	case CC_NDUPACK:
4776 		tp->t_flags &= ~TF_WASFRECOVERY;
4777 		tp->t_flags &= ~TF_WASCRECOVERY;
4778 		if (!IN_FASTRECOVERY(tp->t_flags)) {
4779 			rack->r_ctl.rc_prr_delivered = 0;
4780 			rack->r_ctl.rc_prr_out = 0;
4781 			if (rack->rack_no_prr == 0) {
4782 				rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
4783 				rack_log_to_prr(rack, 2, in_rec_at_entry, line);
4784 			}
4785 			rack->r_ctl.rc_prr_recovery_fs = tp->snd_max - tp->snd_una;
4786 			tp->snd_recover = tp->snd_max;
4787 			if (tp->t_flags2 & TF2_ECN_PERMIT)
4788 				tp->t_flags2 |= TF2_ECN_SND_CWR;
4789 		}
4790 		break;
4791 	case CC_ECN:
4792 		if (!IN_CONGRECOVERY(tp->t_flags) ||
4793 		    /*
4794 		     * Allow ECN reaction on ACK to CWR, if
4795 		     * that data segment was also CE marked.
4796 		     */
4797 		    SEQ_GEQ(ack, tp->snd_recover)) {
4798 			EXIT_CONGRECOVERY(tp->t_flags);
4799 			KMOD_TCPSTAT_INC(tcps_ecn_rcwnd);
4800 			tp->snd_recover = tp->snd_max + 1;
4801 			if (tp->t_flags2 & TF2_ECN_PERMIT)
4802 				tp->t_flags2 |= TF2_ECN_SND_CWR;
4803 		}
4804 		break;
4805 	case CC_RTO:
4806 		tp->t_dupacks = 0;
4807 		tp->t_bytes_acked = 0;
4808 		EXIT_RECOVERY(tp->t_flags);
4809 		tp->snd_ssthresh = max(2, min(tp->snd_wnd, rack->r_ctl.cwnd_to_use) / 2 /
4810 		    ctf_fixed_maxseg(tp)) * ctf_fixed_maxseg(tp);
4811 		orig_cwnd = tp->snd_cwnd;
4812 		tp->snd_cwnd = ctf_fixed_maxseg(tp);
4813 		rack_log_to_prr(rack, 16, orig_cwnd, line);
4814 		if (tp->t_flags2 & TF2_ECN_PERMIT)
4815 			tp->t_flags2 |= TF2_ECN_SND_CWR;
4816 		break;
4817 	case CC_RTO_ERR:
4818 		KMOD_TCPSTAT_INC(tcps_sndrexmitbad);
4819 		/* RTO was unnecessary, so reset everything. */
4820 		tp->snd_cwnd = tp->snd_cwnd_prev;
4821 		tp->snd_ssthresh = tp->snd_ssthresh_prev;
4822 		tp->snd_recover = tp->snd_recover_prev;
4823 		if (tp->t_flags & TF_WASFRECOVERY) {
4824 			ENTER_FASTRECOVERY(tp->t_flags);
4825 			tp->t_flags &= ~TF_WASFRECOVERY;
4826 		}
4827 		if (tp->t_flags & TF_WASCRECOVERY) {
4828 			ENTER_CONGRECOVERY(tp->t_flags);
4829 			tp->t_flags &= ~TF_WASCRECOVERY;
4830 		}
4831 		tp->snd_nxt = tp->snd_max;
4832 		tp->t_badrxtwin = 0;
4833 		break;
4834 	}
4835 	if ((CC_ALGO(tp)->cong_signal != NULL)  &&
4836 	    (type != CC_RTO)){
4837 		tp->t_ccv.curack = ack;
4838 		CC_ALGO(tp)->cong_signal(&tp->t_ccv, type);
4839 	}
4840 	if ((in_rec_at_entry == 0) && IN_RECOVERY(tp->t_flags)) {
4841 		rack_log_to_prr(rack, 15, cwnd_enter, line);
4842 		rack->r_ctl.dsack_byte_cnt = 0;
4843 		rack->r_ctl.retran_during_recovery = 0;
4844 		rack->r_ctl.rc_cwnd_at_erec = cwnd_enter;
4845 		rack->r_ctl.rc_ssthresh_at_erec = ssthresh_enter;
4846 		rack->r_ent_rec_ns = 1;
4847 	}
4848 }
4849 
4850 static inline void
4851 rack_cc_after_idle(struct tcp_rack *rack, struct tcpcb *tp)
4852 {
4853 	uint32_t i_cwnd;
4854 
4855 	INP_WLOCK_ASSERT(tptoinpcb(tp));
4856 
4857 #ifdef NETFLIX_STATS
4858 	KMOD_TCPSTAT_INC(tcps_idle_restarts);
4859 	if (tp->t_state == TCPS_ESTABLISHED)
4860 		KMOD_TCPSTAT_INC(tcps_idle_estrestarts);
4861 #endif
4862 	if (CC_ALGO(tp)->after_idle != NULL)
4863 		CC_ALGO(tp)->after_idle(&tp->t_ccv);
4864 
4865 	if (tp->snd_cwnd == 1)
4866 		i_cwnd = tp->t_maxseg;		/* SYN(-ACK) lost */
4867 	else
4868 		i_cwnd = rc_init_window(rack);
4869 
4870 	/*
4871 	 * Being idle is no different than the initial window. If the cc
4872 	 * clamps it down below the initial window raise it to the initial
4873 	 * window.
4874 	 */
4875 	if (tp->snd_cwnd < i_cwnd) {
4876 		tp->snd_cwnd = i_cwnd;
4877 	}
4878 }
4879 
4880 /*
4881  * Indicate whether this ack should be delayed.  We can delay the ack if
4882  * following conditions are met:
4883  *	- There is no delayed ack timer in progress.
4884  *	- Our last ack wasn't a 0-sized window. We never want to delay
4885  *	  the ack that opens up a 0-sized window.
4886  *	- LRO wasn't used for this segment. We make sure by checking that the
4887  *	  segment size is not larger than the MSS.
4888  *	- Delayed acks are enabled or this is a half-synchronized T/TCP
4889  *	  connection.
4890  */
4891 #define DELAY_ACK(tp, tlen)			 \
4892 	(((tp->t_flags & TF_RXWIN0SENT) == 0) && \
4893 	((tp->t_flags & TF_DELACK) == 0) &&	 \
4894 	(tlen <= tp->t_maxseg) &&		 \
4895 	(tp->t_delayed_ack || (tp->t_flags & TF_NEEDSYN)))
4896 
4897 static struct rack_sendmap *
4898 rack_find_lowest_rsm(struct tcp_rack *rack)
4899 {
4900 	struct rack_sendmap *rsm;
4901 
4902 	/*
4903 	 * Walk the time-order transmitted list looking for an rsm that is
4904 	 * not acked. This will be the one that was sent the longest time
4905 	 * ago that is still outstanding.
4906 	 */
4907 	TAILQ_FOREACH(rsm, &rack->r_ctl.rc_tmap, r_tnext) {
4908 		if (rsm->r_flags & RACK_ACKED) {
4909 			continue;
4910 		}
4911 		goto finish;
4912 	}
4913 finish:
4914 	return (rsm);
4915 }
4916 
4917 static struct rack_sendmap *
4918 rack_find_high_nonack(struct tcp_rack *rack, struct rack_sendmap *rsm)
4919 {
4920 	struct rack_sendmap *prsm;
4921 
4922 	/*
4923 	 * Walk the sequence order list backward until we hit and arrive at
4924 	 * the highest seq not acked. In theory when this is called it
4925 	 * should be the last segment (which it was not).
4926 	 */
4927 	prsm = rsm;
4928 	RB_FOREACH_REVERSE_FROM(prsm, rack_rb_tree_head, rsm) {
4929 		if (prsm->r_flags & (RACK_ACKED | RACK_HAS_FIN)) {
4930 			continue;
4931 		}
4932 		return (prsm);
4933 	}
4934 	return (NULL);
4935 }
4936 
4937 static uint32_t
4938 rack_calc_thresh_rack(struct tcp_rack *rack, uint32_t srtt, uint32_t cts)
4939 {
4940 	int32_t lro;
4941 	uint32_t thresh;
4942 
4943 	/*
4944 	 * lro is the flag we use to determine if we have seen reordering.
4945 	 * If it gets set we have seen reordering. The reorder logic either
4946 	 * works in one of two ways:
4947 	 *
4948 	 * If reorder-fade is configured, then we track the last time we saw
4949 	 * re-ordering occur. If we reach the point where enough time as
4950 	 * passed we no longer consider reordering has occuring.
4951 	 *
4952 	 * Or if reorder-face is 0, then once we see reordering we consider
4953 	 * the connection to alway be subject to reordering and just set lro
4954 	 * to 1.
4955 	 *
4956 	 * In the end if lro is non-zero we add the extra time for
4957 	 * reordering in.
4958 	 */
4959 	if (srtt == 0)
4960 		srtt = 1;
4961 	if (rack->r_ctl.rc_reorder_ts) {
4962 		if (rack->r_ctl.rc_reorder_fade) {
4963 			if (SEQ_GEQ(cts, rack->r_ctl.rc_reorder_ts)) {
4964 				lro = cts - rack->r_ctl.rc_reorder_ts;
4965 				if (lro == 0) {
4966 					/*
4967 					 * No time as passed since the last
4968 					 * reorder, mark it as reordering.
4969 					 */
4970 					lro = 1;
4971 				}
4972 			} else {
4973 				/* Negative time? */
4974 				lro = 0;
4975 			}
4976 			if (lro > rack->r_ctl.rc_reorder_fade) {
4977 				/* Turn off reordering seen too */
4978 				rack->r_ctl.rc_reorder_ts = 0;
4979 				lro = 0;
4980 			}
4981 		} else {
4982 			/* Reodering does not fade */
4983 			lro = 1;
4984 		}
4985 	} else {
4986 		lro = 0;
4987 	}
4988 	if (rack->rc_rack_tmr_std_based == 0) {
4989 		thresh = srtt + rack->r_ctl.rc_pkt_delay;
4990 	} else {
4991 		/* Standards based pkt-delay is 1/4 srtt */
4992 		thresh = srtt +  (srtt >> 2);
4993 	}
4994 	if (lro && (rack->rc_rack_tmr_std_based == 0)) {
4995 		/* It must be set, if not you get 1/4 rtt */
4996 		if (rack->r_ctl.rc_reorder_shift)
4997 			thresh += (srtt >> rack->r_ctl.rc_reorder_shift);
4998 		else
4999 			thresh += (srtt >> 2);
5000 	}
5001 	if (rack->rc_rack_use_dsack &&
5002 	    lro &&
5003 	    (rack->r_ctl.num_dsack > 0)) {
5004 		/*
5005 		 * We only increase the reordering window if we
5006 		 * have seen reordering <and> we have a DSACK count.
5007 		 */
5008 		thresh += rack->r_ctl.num_dsack * (srtt >> 2);
5009 		rack_log_dsack_event(rack, 4, __LINE__, srtt, thresh);
5010 	}
5011 	/* SRTT * 2 is the ceiling */
5012 	if (thresh > (srtt * 2)) {
5013 		thresh = srtt * 2;
5014 	}
5015 	/* And we don't want it above the RTO max either */
5016 	if (thresh > rack_rto_max) {
5017 		thresh = rack_rto_max;
5018 	}
5019 	rack_log_dsack_event(rack, 6, __LINE__, srtt, thresh);
5020 	return (thresh);
5021 }
5022 
5023 static uint32_t
5024 rack_calc_thresh_tlp(struct tcpcb *tp, struct tcp_rack *rack,
5025 		     struct rack_sendmap *rsm, uint32_t srtt)
5026 {
5027 	struct rack_sendmap *prsm;
5028 	uint32_t thresh, len;
5029 	int segsiz;
5030 
5031 	if (srtt == 0)
5032 		srtt = 1;
5033 	if (rack->r_ctl.rc_tlp_threshold)
5034 		thresh = srtt + (srtt / rack->r_ctl.rc_tlp_threshold);
5035 	else
5036 		thresh = (srtt * 2);
5037 
5038 	/* Get the previous sent packet, if any */
5039 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
5040 	len = rsm->r_end - rsm->r_start;
5041 	if (rack->rack_tlp_threshold_use == TLP_USE_ID) {
5042 		/* Exactly like the ID */
5043 		if (((tp->snd_max - tp->snd_una) - rack->r_ctl.rc_sacked + rack->r_ctl.rc_holes_rxt) <= segsiz) {
5044 			uint32_t alt_thresh;
5045 			/*
5046 			 * Compensate for delayed-ack with the d-ack time.
5047 			 */
5048 			alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time;
5049 			if (alt_thresh > thresh)
5050 				thresh = alt_thresh;
5051 		}
5052 	} else if (rack->rack_tlp_threshold_use == TLP_USE_TWO_ONE) {
5053 		/* 2.1 behavior */
5054 		prsm = TAILQ_PREV(rsm, rack_head, r_tnext);
5055 		if (prsm && (len <= segsiz)) {
5056 			/*
5057 			 * Two packets outstanding, thresh should be (2*srtt) +
5058 			 * possible inter-packet delay (if any).
5059 			 */
5060 			uint32_t inter_gap = 0;
5061 			int idx, nidx;
5062 
5063 			idx = rsm->r_rtr_cnt - 1;
5064 			nidx = prsm->r_rtr_cnt - 1;
5065 			if (rsm->r_tim_lastsent[nidx] >= prsm->r_tim_lastsent[idx]) {
5066 				/* Yes it was sent later (or at the same time) */
5067 				inter_gap = rsm->r_tim_lastsent[idx] - prsm->r_tim_lastsent[nidx];
5068 			}
5069 			thresh += inter_gap;
5070 		} else if (len <= segsiz) {
5071 			/*
5072 			 * Possibly compensate for delayed-ack.
5073 			 */
5074 			uint32_t alt_thresh;
5075 
5076 			alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time;
5077 			if (alt_thresh > thresh)
5078 				thresh = alt_thresh;
5079 		}
5080 	} else if (rack->rack_tlp_threshold_use == TLP_USE_TWO_TWO) {
5081 		/* 2.2 behavior */
5082 		if (len <= segsiz) {
5083 			uint32_t alt_thresh;
5084 			/*
5085 			 * Compensate for delayed-ack with the d-ack time.
5086 			 */
5087 			alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time;
5088 			if (alt_thresh > thresh)
5089 				thresh = alt_thresh;
5090 		}
5091 	}
5092 	/* Not above an RTO */
5093 	if (thresh > tp->t_rxtcur) {
5094 		thresh = tp->t_rxtcur;
5095 	}
5096 	/* Not above a RTO max */
5097 	if (thresh > rack_rto_max) {
5098 		thresh = rack_rto_max;
5099 	}
5100 	/* Apply user supplied min TLP */
5101 	if (thresh < rack_tlp_min) {
5102 		thresh = rack_tlp_min;
5103 	}
5104 	return (thresh);
5105 }
5106 
5107 static uint32_t
5108 rack_grab_rtt(struct tcpcb *tp, struct tcp_rack *rack)
5109 {
5110 	/*
5111 	 * We want the rack_rtt which is the
5112 	 * last rtt we measured. However if that
5113 	 * does not exist we fallback to the srtt (which
5114 	 * we probably will never do) and then as a last
5115 	 * resort we use RACK_INITIAL_RTO if no srtt is
5116 	 * yet set.
5117 	 */
5118 	if (rack->rc_rack_rtt)
5119 		return (rack->rc_rack_rtt);
5120 	else if (tp->t_srtt == 0)
5121 		return (RACK_INITIAL_RTO);
5122 	return (tp->t_srtt);
5123 }
5124 
5125 static struct rack_sendmap *
5126 rack_check_recovery_mode(struct tcpcb *tp, uint32_t tsused)
5127 {
5128 	/*
5129 	 * Check to see that we don't need to fall into recovery. We will
5130 	 * need to do so if our oldest transmit is past the time we should
5131 	 * have had an ack.
5132 	 */
5133 	struct tcp_rack *rack;
5134 	struct rack_sendmap *rsm;
5135 	int32_t idx;
5136 	uint32_t srtt, thresh;
5137 
5138 	rack = (struct tcp_rack *)tp->t_fb_ptr;
5139 	if (RB_EMPTY(&rack->r_ctl.rc_mtree)) {
5140 		return (NULL);
5141 	}
5142 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
5143 	if (rsm == NULL)
5144 		return (NULL);
5145 
5146 
5147 	if (rsm->r_flags & RACK_ACKED) {
5148 		rsm = rack_find_lowest_rsm(rack);
5149 		if (rsm == NULL)
5150 			return (NULL);
5151 	}
5152 	idx = rsm->r_rtr_cnt - 1;
5153 	srtt = rack_grab_rtt(tp, rack);
5154 	thresh = rack_calc_thresh_rack(rack, srtt, tsused);
5155 	if (TSTMP_LT(tsused, ((uint32_t)rsm->r_tim_lastsent[idx]))) {
5156 		return (NULL);
5157 	}
5158 	if ((tsused - ((uint32_t)rsm->r_tim_lastsent[idx])) < thresh) {
5159 		return (NULL);
5160 	}
5161 	/* Ok if we reach here we are over-due and this guy can be sent */
5162 	rack_cong_signal(tp, CC_NDUPACK, tp->snd_una, __LINE__);
5163 	return (rsm);
5164 }
5165 
5166 static uint32_t
5167 rack_get_persists_timer_val(struct tcpcb *tp, struct tcp_rack *rack)
5168 {
5169 	int32_t t;
5170 	int32_t tt;
5171 	uint32_t ret_val;
5172 
5173 	t = (tp->t_srtt + (tp->t_rttvar << 2));
5174 	RACK_TCPT_RANGESET(tt, t * tcp_backoff[tp->t_rxtshift],
5175  	    rack_persist_min, rack_persist_max, rack->r_ctl.timer_slop);
5176 	rack->r_ctl.rc_hpts_flags |= PACE_TMR_PERSIT;
5177 	ret_val = (uint32_t)tt;
5178 	return (ret_val);
5179 }
5180 
5181 static uint32_t
5182 rack_timer_start(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int sup_rack)
5183 {
5184 	/*
5185 	 * Start the FR timer, we do this based on getting the first one in
5186 	 * the rc_tmap. Note that if its NULL we must stop the timer. in all
5187 	 * events we need to stop the running timer (if its running) before
5188 	 * starting the new one.
5189 	 */
5190 	uint32_t thresh, exp, to, srtt, time_since_sent, tstmp_touse;
5191 	uint32_t srtt_cur;
5192 	int32_t idx;
5193 	int32_t is_tlp_timer = 0;
5194 	struct rack_sendmap *rsm;
5195 
5196 	if (rack->t_timers_stopped) {
5197 		/* All timers have been stopped none are to run */
5198 		return (0);
5199 	}
5200 	if (rack->rc_in_persist) {
5201 		/* We can't start any timer in persists */
5202 		return (rack_get_persists_timer_val(tp, rack));
5203 	}
5204 	rack->rc_on_min_to = 0;
5205 	if ((tp->t_state < TCPS_ESTABLISHED) ||
5206 	    ((tp->t_flags & TF_SACK_PERMIT) == 0)) {
5207 		goto activate_rxt;
5208 	}
5209 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
5210 	if ((rsm == NULL) || sup_rack) {
5211 		/* Nothing on the send map or no rack */
5212 activate_rxt:
5213 		time_since_sent = 0;
5214 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
5215 		if (rsm) {
5216 			/*
5217 			 * Should we discount the RTX timer any?
5218 			 *
5219 			 * We want to discount it the smallest amount.
5220 			 * If a timer (Rack/TLP or RXT) has gone off more
5221 			 * recently thats the discount we want to use (now - timer time).
5222 			 * If the retransmit of the oldest packet was more recent then
5223 			 * we want to use that (now - oldest-packet-last_transmit_time).
5224 			 *
5225 			 */
5226 			idx = rsm->r_rtr_cnt - 1;
5227 			if (TSTMP_GEQ(rack->r_ctl.rc_tlp_rxt_last_time, ((uint32_t)rsm->r_tim_lastsent[idx])))
5228 				tstmp_touse = (uint32_t)rack->r_ctl.rc_tlp_rxt_last_time;
5229 			else
5230 				tstmp_touse = (uint32_t)rsm->r_tim_lastsent[idx];
5231 			if (TSTMP_GT(cts, tstmp_touse))
5232 			    time_since_sent = cts - tstmp_touse;
5233 		}
5234 		if (SEQ_LT(tp->snd_una, tp->snd_max) ||
5235 		    sbavail(&tptosocket(tp)->so_snd)) {
5236 			rack->r_ctl.rc_hpts_flags |= PACE_TMR_RXT;
5237 			to = tp->t_rxtcur;
5238 			if (to > time_since_sent)
5239 				to -= time_since_sent;
5240 			else
5241 				to = rack->r_ctl.rc_min_to;
5242 			if (to == 0)
5243 				to = 1;
5244 			/* Special case for KEEPINIT */
5245 			if ((TCPS_HAVEESTABLISHED(tp->t_state) == 0) &&
5246 			    (TP_KEEPINIT(tp) != 0) &&
5247 			    rsm) {
5248 				/*
5249 				 * We have to put a ceiling on the rxt timer
5250 				 * of the keep-init timeout.
5251 				 */
5252 				uint32_t max_time, red;
5253 
5254 				max_time = TICKS_2_USEC(TP_KEEPINIT(tp));
5255 				if (TSTMP_GT(cts, (uint32_t)rsm->r_tim_lastsent[0])) {
5256 					red = (cts - (uint32_t)rsm->r_tim_lastsent[0]);
5257 					if (red < max_time)
5258 						max_time -= red;
5259 					else
5260 						max_time = 1;
5261 				}
5262 				/* Reduce timeout to the keep value if needed */
5263 				if (max_time < to)
5264 					to = max_time;
5265 			}
5266 			return (to);
5267 		}
5268 		return (0);
5269 	}
5270 	if (rsm->r_flags & RACK_ACKED) {
5271 		rsm = rack_find_lowest_rsm(rack);
5272 		if (rsm == NULL) {
5273 			/* No lowest? */
5274 			goto activate_rxt;
5275 		}
5276 	}
5277 	if (rack->sack_attack_disable) {
5278 		/*
5279 		 * We don't want to do
5280 		 * any TLP's if you are an attacker.
5281 		 * Though if you are doing what
5282 		 * is expected you may still have
5283 		 * SACK-PASSED marks.
5284 		 */
5285 		goto activate_rxt;
5286 	}
5287 	/* Convert from ms to usecs */
5288 	if ((rsm->r_flags & RACK_SACK_PASSED) ||
5289 	    (rsm->r_flags & RACK_RWND_COLLAPSED) ||
5290 	    (rsm->r_dupack >= DUP_ACK_THRESHOLD)) {
5291 		if ((tp->t_flags & TF_SENTFIN) &&
5292 		    ((tp->snd_max - tp->snd_una) == 1) &&
5293 		    (rsm->r_flags & RACK_HAS_FIN)) {
5294 			/*
5295 			 * We don't start a rack timer if all we have is a
5296 			 * FIN outstanding.
5297 			 */
5298 			goto activate_rxt;
5299 		}
5300 		if ((rack->use_rack_rr == 0) &&
5301 		    (IN_FASTRECOVERY(tp->t_flags)) &&
5302 		    (rack->rack_no_prr == 0) &&
5303 		     (rack->r_ctl.rc_prr_sndcnt  < ctf_fixed_maxseg(tp))) {
5304 			/*
5305 			 * We are not cheating, in recovery  and
5306 			 * not enough ack's to yet get our next
5307 			 * retransmission out.
5308 			 *
5309 			 * Note that classified attackers do not
5310 			 * get to use the rack-cheat.
5311 			 */
5312 			goto activate_tlp;
5313 		}
5314 		srtt = rack_grab_rtt(tp, rack);
5315 		thresh = rack_calc_thresh_rack(rack, srtt, cts);
5316 		idx = rsm->r_rtr_cnt - 1;
5317 		exp = ((uint32_t)rsm->r_tim_lastsent[idx]) + thresh;
5318 		if (SEQ_GEQ(exp, cts)) {
5319 			to = exp - cts;
5320 			if (to < rack->r_ctl.rc_min_to) {
5321 				to = rack->r_ctl.rc_min_to;
5322 				if (rack->r_rr_config == 3)
5323 					rack->rc_on_min_to = 1;
5324 			}
5325 		} else {
5326 			to = rack->r_ctl.rc_min_to;
5327 			if (rack->r_rr_config == 3)
5328 				rack->rc_on_min_to = 1;
5329 		}
5330 	} else {
5331 		/* Ok we need to do a TLP not RACK */
5332 activate_tlp:
5333 		if ((rack->rc_tlp_in_progress != 0) &&
5334 		    (rack->r_ctl.rc_tlp_cnt_out >= rack_tlp_limit)) {
5335 			/*
5336 			 * The previous send was a TLP and we have sent
5337 			 * N TLP's without sending new data.
5338 			 */
5339 			goto activate_rxt;
5340 		}
5341 		rsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_tmap, rack_sendmap, r_tnext);
5342 		if (rsm == NULL) {
5343 			/* We found no rsm to TLP with. */
5344 			goto activate_rxt;
5345 		}
5346 		if (rsm->r_flags & RACK_HAS_FIN) {
5347 			/* If its a FIN we dont do TLP */
5348 			rsm = NULL;
5349 			goto activate_rxt;
5350 		}
5351 		idx = rsm->r_rtr_cnt - 1;
5352 		time_since_sent = 0;
5353 		if (TSTMP_GEQ(((uint32_t)rsm->r_tim_lastsent[idx]), rack->r_ctl.rc_tlp_rxt_last_time))
5354 			tstmp_touse = (uint32_t)rsm->r_tim_lastsent[idx];
5355 		else
5356 			tstmp_touse = (uint32_t)rack->r_ctl.rc_tlp_rxt_last_time;
5357 		if (TSTMP_GT(cts, tstmp_touse))
5358 		    time_since_sent = cts - tstmp_touse;
5359 		is_tlp_timer = 1;
5360 		if (tp->t_srtt) {
5361 			if ((rack->rc_srtt_measure_made == 0) &&
5362 			    (tp->t_srtt == 1)) {
5363 				/*
5364 				 * If another stack as run and set srtt to 1,
5365 				 * then the srtt was 0, so lets use the initial.
5366 				 */
5367 				srtt = RACK_INITIAL_RTO;
5368 			} else {
5369 				srtt_cur = tp->t_srtt;
5370 				srtt = srtt_cur;
5371 			}
5372 		} else
5373 			srtt = RACK_INITIAL_RTO;
5374 		/*
5375 		 * If the SRTT is not keeping up and the
5376 		 * rack RTT has spiked we want to use
5377 		 * the last RTT not the smoothed one.
5378 		 */
5379 		if (rack_tlp_use_greater &&
5380 		    tp->t_srtt &&
5381 		    (srtt < rack_grab_rtt(tp, rack))) {
5382 			srtt = rack_grab_rtt(tp, rack);
5383 		}
5384 		thresh = rack_calc_thresh_tlp(tp, rack, rsm, srtt);
5385 		if (thresh > time_since_sent) {
5386 			to = thresh - time_since_sent;
5387 		} else {
5388 			to = rack->r_ctl.rc_min_to;
5389 			rack_log_alt_to_to_cancel(rack,
5390 						  thresh,		/* flex1 */
5391 						  time_since_sent,	/* flex2 */
5392 						  tstmp_touse,		/* flex3 */
5393 						  rack->r_ctl.rc_tlp_rxt_last_time, /* flex4 */
5394 						  (uint32_t)rsm->r_tim_lastsent[idx],
5395 						  srtt,
5396 						  idx, 99);
5397 		}
5398 		if (to < rack_tlp_min) {
5399 			to = rack_tlp_min;
5400 		}
5401 		if (to > TICKS_2_USEC(TCPTV_REXMTMAX)) {
5402 			/*
5403 			 * If the TLP time works out to larger than the max
5404 			 * RTO lets not do TLP.. just RTO.
5405 			 */
5406 			goto activate_rxt;
5407 		}
5408 	}
5409 	if (is_tlp_timer == 0) {
5410 		rack->r_ctl.rc_hpts_flags |= PACE_TMR_RACK;
5411 	} else {
5412 		rack->r_ctl.rc_hpts_flags |= PACE_TMR_TLP;
5413 	}
5414 	if (to == 0)
5415 		to = 1;
5416 	return (to);
5417 }
5418 
5419 static void
5420 rack_enter_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5421 {
5422 	if (rack->rc_in_persist == 0) {
5423 		if (tp->t_flags & TF_GPUTINPROG) {
5424 			/*
5425 			 * Stop the goodput now, the calling of the
5426 			 * measurement function clears the flag.
5427 			 */
5428 			rack_do_goodput_measurement(tp, rack, tp->snd_una, __LINE__,
5429 						    RACK_QUALITY_PERSIST);
5430 		}
5431 #ifdef NETFLIX_SHARED_CWND
5432 		if (rack->r_ctl.rc_scw) {
5433 			tcp_shared_cwnd_idle(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
5434 			rack->rack_scwnd_is_idle = 1;
5435 		}
5436 #endif
5437 		rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
5438 		if (rack->r_ctl.rc_went_idle_time == 0)
5439 			rack->r_ctl.rc_went_idle_time = 1;
5440 		rack_timer_cancel(tp, rack, cts, __LINE__);
5441 		rack->r_ctl.persist_lost_ends = 0;
5442 		rack->probe_not_answered = 0;
5443 		rack->forced_ack = 0;
5444 		tp->t_rxtshift = 0;
5445 		RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
5446 			      rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
5447 		rack->rc_in_persist = 1;
5448 	}
5449 }
5450 
5451 static void
5452 rack_exit_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5453 {
5454 	if (tcp_in_hpts(rack->rc_inp)) {
5455 		tcp_hpts_remove(rack->rc_inp);
5456 		rack->r_ctl.rc_hpts_flags = 0;
5457 	}
5458 #ifdef NETFLIX_SHARED_CWND
5459 	if (rack->r_ctl.rc_scw) {
5460 		tcp_shared_cwnd_active(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
5461 		rack->rack_scwnd_is_idle = 0;
5462 	}
5463 #endif
5464 	if (rack->rc_gp_dyn_mul &&
5465 	    (rack->use_fixed_rate == 0) &&
5466 	    (rack->rc_always_pace)) {
5467 		/*
5468 		 * Do we count this as if a probe-rtt just
5469 		 * finished?
5470 		 */
5471 		uint32_t time_idle, idle_min;
5472 
5473 		time_idle = tcp_get_usecs(NULL) - rack->r_ctl.rc_went_idle_time;
5474 		idle_min = rack_min_probertt_hold;
5475 		if (rack_probertt_gpsrtt_cnt_div) {
5476 			uint64_t extra;
5477 			extra = (uint64_t)rack->r_ctl.rc_gp_srtt *
5478 				(uint64_t)rack_probertt_gpsrtt_cnt_mul;
5479 			extra /= (uint64_t)rack_probertt_gpsrtt_cnt_div;
5480 			idle_min += (uint32_t)extra;
5481 		}
5482 		if (time_idle >= idle_min) {
5483 			/* Yes, we count it as a probe-rtt. */
5484 			uint32_t us_cts;
5485 
5486 			us_cts = tcp_get_usecs(NULL);
5487 			if (rack->in_probe_rtt == 0) {
5488 				rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
5489 				rack->r_ctl.rc_time_probertt_entered = rack->r_ctl.rc_lower_rtt_us_cts;
5490 				rack->r_ctl.rc_time_probertt_starts = rack->r_ctl.rc_lower_rtt_us_cts;
5491 				rack->r_ctl.rc_time_of_last_probertt = rack->r_ctl.rc_lower_rtt_us_cts;
5492 			} else {
5493 				rack_exit_probertt(rack, us_cts);
5494 			}
5495 		}
5496 	}
5497 	rack->rc_in_persist = 0;
5498 	rack->r_ctl.rc_went_idle_time = 0;
5499 	tp->t_rxtshift = 0;
5500 	RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
5501 	   rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
5502 	rack->r_ctl.rc_agg_delayed = 0;
5503 	rack->r_early = 0;
5504 	rack->r_late = 0;
5505 	rack->r_ctl.rc_agg_early = 0;
5506 }
5507 
5508 static void
5509 rack_log_hpts_diag(struct tcp_rack *rack, uint32_t cts,
5510 		   struct hpts_diag *diag, struct timeval *tv)
5511 {
5512 	if (rack_verbose_logging && rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
5513 		union tcp_log_stackspecific log;
5514 
5515 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
5516 		log.u_bbr.flex1 = diag->p_nxt_slot;
5517 		log.u_bbr.flex2 = diag->p_cur_slot;
5518 		log.u_bbr.flex3 = diag->slot_req;
5519 		log.u_bbr.flex4 = diag->inp_hptsslot;
5520 		log.u_bbr.flex5 = diag->slot_remaining;
5521 		log.u_bbr.flex6 = diag->need_new_to;
5522 		log.u_bbr.flex7 = diag->p_hpts_active;
5523 		log.u_bbr.flex8 = diag->p_on_min_sleep;
5524 		/* Hijack other fields as needed */
5525 		log.u_bbr.epoch = diag->have_slept;
5526 		log.u_bbr.lt_epoch = diag->yet_to_sleep;
5527 		log.u_bbr.pkts_out = diag->co_ret;
5528 		log.u_bbr.applimited = diag->hpts_sleep_time;
5529 		log.u_bbr.delivered = diag->p_prev_slot;
5530 		log.u_bbr.inflight = diag->p_runningslot;
5531 		log.u_bbr.bw_inuse = diag->wheel_slot;
5532 		log.u_bbr.rttProp = diag->wheel_cts;
5533 		log.u_bbr.timeStamp = cts;
5534 		log.u_bbr.delRate = diag->maxslots;
5535 		log.u_bbr.cur_del_rate = diag->p_curtick;
5536 		log.u_bbr.cur_del_rate <<= 32;
5537 		log.u_bbr.cur_del_rate |= diag->p_lasttick;
5538 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
5539 		    &rack->rc_inp->inp_socket->so_rcv,
5540 		    &rack->rc_inp->inp_socket->so_snd,
5541 		    BBR_LOG_HPTSDIAG, 0,
5542 		    0, &log, false, tv);
5543 	}
5544 
5545 }
5546 
5547 static void
5548 rack_log_wakeup(struct tcpcb *tp, struct tcp_rack *rack, struct sockbuf *sb, uint32_t len, int type)
5549 {
5550 	if (rack_verbose_logging && rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
5551 		union tcp_log_stackspecific log;
5552 		struct timeval tv;
5553 
5554 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
5555 		log.u_bbr.flex1 = sb->sb_flags;
5556 		log.u_bbr.flex2 = len;
5557 		log.u_bbr.flex3 = sb->sb_state;
5558 		log.u_bbr.flex8 = type;
5559 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
5560 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
5561 		    &rack->rc_inp->inp_socket->so_rcv,
5562 		    &rack->rc_inp->inp_socket->so_snd,
5563 		    TCP_LOG_SB_WAKE, 0,
5564 		    len, &log, false, &tv);
5565 	}
5566 }
5567 
5568 static void
5569 rack_start_hpts_timer(struct tcp_rack *rack, struct tcpcb *tp, uint32_t cts,
5570       int32_t slot, uint32_t tot_len_this_send, int sup_rack)
5571 {
5572 	struct hpts_diag diag;
5573 	struct inpcb *inp = tptoinpcb(tp);
5574 	struct timeval tv;
5575 	uint32_t delayed_ack = 0;
5576 	uint32_t hpts_timeout;
5577 	uint32_t entry_slot = slot;
5578 	uint8_t stopped;
5579 	uint32_t left = 0;
5580 	uint32_t us_cts;
5581 
5582 	if ((tp->t_state == TCPS_CLOSED) ||
5583 	    (tp->t_state == TCPS_LISTEN)) {
5584 		return;
5585 	}
5586 	if (tcp_in_hpts(inp)) {
5587 		/* Already on the pacer */
5588 		return;
5589 	}
5590 	stopped = rack->rc_tmr_stopped;
5591 	if (stopped && TSTMP_GT(rack->r_ctl.rc_timer_exp, cts)) {
5592 		left = rack->r_ctl.rc_timer_exp - cts;
5593 	}
5594 	rack->r_ctl.rc_timer_exp = 0;
5595 	rack->r_ctl.rc_hpts_flags = 0;
5596 	us_cts = tcp_get_usecs(&tv);
5597 	/* Now early/late accounting */
5598 	rack_log_pacing_delay_calc(rack, entry_slot, slot, 0, 0, 0, 26, __LINE__, NULL, 0);
5599 	if (rack->r_early && (rack->rc_ack_can_sendout_data == 0)) {
5600 		/*
5601 		 * We have a early carry over set,
5602 		 * we can always add more time so we
5603 		 * can always make this compensation.
5604 		 *
5605 		 * Note if ack's are allowed to wake us do not
5606 		 * penalize the next timer for being awoke
5607 		 * by an ack aka the rc_agg_early (non-paced mode).
5608 		 */
5609 		slot += rack->r_ctl.rc_agg_early;
5610 		rack->r_early = 0;
5611 		rack->r_ctl.rc_agg_early = 0;
5612 	}
5613 	if (rack->r_late) {
5614 		/*
5615 		 * This is harder, we can
5616 		 * compensate some but it
5617 		 * really depends on what
5618 		 * the current pacing time is.
5619 		 */
5620 		if (rack->r_ctl.rc_agg_delayed >= slot) {
5621 			/*
5622 			 * We can't compensate for it all.
5623 			 * And we have to have some time
5624 			 * on the clock. We always have a min
5625 			 * 10 slots (10 x 10 i.e. 100 usecs).
5626 			 */
5627 			if (slot <= HPTS_TICKS_PER_SLOT) {
5628 				/* We gain delay */
5629 				rack->r_ctl.rc_agg_delayed += (HPTS_TICKS_PER_SLOT - slot);
5630 				slot = HPTS_TICKS_PER_SLOT;
5631 			} else {
5632 				/* We take off some */
5633 				rack->r_ctl.rc_agg_delayed -= (slot - HPTS_TICKS_PER_SLOT);
5634 				slot = HPTS_TICKS_PER_SLOT;
5635 			}
5636 		} else {
5637 			slot -= rack->r_ctl.rc_agg_delayed;
5638 			rack->r_ctl.rc_agg_delayed = 0;
5639 			/* Make sure we have 100 useconds at minimum */
5640 			if (slot < HPTS_TICKS_PER_SLOT) {
5641 				rack->r_ctl.rc_agg_delayed = HPTS_TICKS_PER_SLOT - slot;
5642 				slot = HPTS_TICKS_PER_SLOT;
5643 			}
5644 			if (rack->r_ctl.rc_agg_delayed == 0)
5645 				rack->r_late = 0;
5646 		}
5647 	}
5648 	if (slot) {
5649 		/* We are pacing too */
5650 		rack->r_ctl.rc_hpts_flags |= PACE_PKT_OUTPUT;
5651 	}
5652 	hpts_timeout = rack_timer_start(tp, rack, cts, sup_rack);
5653 #ifdef NETFLIX_EXP_DETECTION
5654 	if (rack->sack_attack_disable &&
5655 	    (slot < tcp_sad_pacing_interval)) {
5656 		/*
5657 		 * We have a potential attacker on
5658 		 * the line. We have possibly some
5659 		 * (or now) pacing time set. We want to
5660 		 * slow down the processing of sacks by some
5661 		 * amount (if it is an attacker). Set the default
5662 		 * slot for attackers in place (unless the original
5663 		 * interval is longer). Its stored in
5664 		 * micro-seconds, so lets convert to msecs.
5665 		 */
5666 		slot = tcp_sad_pacing_interval;
5667 	}
5668 #endif
5669 	if (tp->t_flags & TF_DELACK) {
5670 		delayed_ack = TICKS_2_USEC(tcp_delacktime);
5671 		rack->r_ctl.rc_hpts_flags |= PACE_TMR_DELACK;
5672 	}
5673 	if (delayed_ack && ((hpts_timeout == 0) ||
5674 			    (delayed_ack < hpts_timeout)))
5675 		hpts_timeout = delayed_ack;
5676 	else
5677 		rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_DELACK;
5678 	/*
5679 	 * If no timers are going to run and we will fall off the hptsi
5680 	 * wheel, we resort to a keep-alive timer if its configured.
5681 	 */
5682 	if ((hpts_timeout == 0) &&
5683 	    (slot == 0)) {
5684 		if ((V_tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
5685 		    (tp->t_state <= TCPS_CLOSING)) {
5686 			/*
5687 			 * Ok we have no timer (persists, rack, tlp, rxt  or
5688 			 * del-ack), we don't have segments being paced. So
5689 			 * all that is left is the keepalive timer.
5690 			 */
5691 			if (TCPS_HAVEESTABLISHED(tp->t_state)) {
5692 				/* Get the established keep-alive time */
5693 				hpts_timeout = TICKS_2_USEC(TP_KEEPIDLE(tp));
5694 			} else {
5695 				/*
5696 				 * Get the initial setup keep-alive time,
5697 				 * note that this is probably not going to
5698 				 * happen, since rack will be running a rxt timer
5699 				 * if a SYN of some sort is outstanding. It is
5700 				 * actually handled in rack_timeout_rxt().
5701 				 */
5702 				hpts_timeout = TICKS_2_USEC(TP_KEEPINIT(tp));
5703 			}
5704 			rack->r_ctl.rc_hpts_flags |= PACE_TMR_KEEP;
5705 			if (rack->in_probe_rtt) {
5706 				/*
5707 				 * We want to instead not wake up a long time from
5708 				 * now but to wake up about the time we would
5709 				 * exit probe-rtt and initiate a keep-alive ack.
5710 				 * This will get us out of probe-rtt and update
5711 				 * our min-rtt.
5712 				 */
5713 				hpts_timeout = rack_min_probertt_hold;
5714 			}
5715 		}
5716 	}
5717 	if (left && (stopped & (PACE_TMR_KEEP | PACE_TMR_DELACK)) ==
5718 	    (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK)) {
5719 		/*
5720 		 * RACK, TLP, persists and RXT timers all are restartable
5721 		 * based on actions input .. i.e we received a packet (ack
5722 		 * or sack) and that changes things (rw, or snd_una etc).
5723 		 * Thus we can restart them with a new value. For
5724 		 * keep-alive, delayed_ack we keep track of what was left
5725 		 * and restart the timer with a smaller value.
5726 		 */
5727 		if (left < hpts_timeout)
5728 			hpts_timeout = left;
5729 	}
5730 	if (hpts_timeout) {
5731 		/*
5732 		 * Hack alert for now we can't time-out over 2,147,483
5733 		 * seconds (a bit more than 596 hours), which is probably ok
5734 		 * :).
5735 		 */
5736 		if (hpts_timeout > 0x7ffffffe)
5737 			hpts_timeout = 0x7ffffffe;
5738 		rack->r_ctl.rc_timer_exp = cts + hpts_timeout;
5739 	}
5740 	rack_log_pacing_delay_calc(rack, entry_slot, slot, hpts_timeout, 0, 0, 27, __LINE__, NULL, 0);
5741 	if ((rack->gp_ready == 0) &&
5742 	    (rack->use_fixed_rate == 0) &&
5743 	    (hpts_timeout < slot) &&
5744 	    (rack->r_ctl.rc_hpts_flags & (PACE_TMR_TLP|PACE_TMR_RXT))) {
5745 		/*
5746 		 * We have no good estimate yet for the
5747 		 * old clunky burst mitigation or the
5748 		 * real pacing. And the tlp or rxt is smaller
5749 		 * than the pacing calculation. Lets not
5750 		 * pace that long since we know the calculation
5751 		 * so far is not accurate.
5752 		 */
5753 		slot = hpts_timeout;
5754 	}
5755 	/**
5756 	 * Turn off all the flags for queuing by default. The
5757 	 * flags have important meanings to what happens when
5758 	 * LRO interacts with the transport. Most likely (by default now)
5759 	 * mbuf_queueing and ack compression are on. So the transport
5760 	 * has a couple of flags that control what happens (if those
5761 	 * are not on then these flags won't have any effect since it
5762 	 * won't go through the queuing LRO path).
5763 	 *
5764 	 * INP_MBUF_QUEUE_READY - This flags says that I am busy
5765 	 *                        pacing output, so don't disturb. But
5766 	 *                        it also means LRO can wake me if there
5767 	 *                        is a SACK arrival.
5768 	 *
5769 	 * INP_DONT_SACK_QUEUE - This flag is used in conjunction
5770 	 *                       with the above flag (QUEUE_READY) and
5771 	 *                       when present it says don't even wake me
5772 	 *                       if a SACK arrives.
5773 	 *
5774 	 * The idea behind these flags is that if we are pacing we
5775 	 * set the MBUF_QUEUE_READY and only get woken up if
5776 	 * a SACK arrives (which could change things) or if
5777 	 * our pacing timer expires. If, however, we have a rack
5778 	 * timer running, then we don't even want a sack to wake
5779 	 * us since the rack timer has to expire before we can send.
5780 	 *
5781 	 * Other cases should usually have none of the flags set
5782 	 * so LRO can call into us.
5783 	 */
5784 	inp->inp_flags2 &= ~(INP_DONT_SACK_QUEUE|INP_MBUF_QUEUE_READY);
5785 	if (slot) {
5786 		rack->r_ctl.rc_last_output_to = us_cts + slot;
5787 		/*
5788 		 * A pacing timer (slot) is being set, in
5789 		 * such a case we cannot send (we are blocked by
5790 		 * the timer). So lets tell LRO that it should not
5791 		 * wake us unless there is a SACK. Note this only
5792 		 * will be effective if mbuf queueing is on or
5793 		 * compressed acks are being processed.
5794 		 */
5795 		inp->inp_flags2 |= INP_MBUF_QUEUE_READY;
5796 		/*
5797 		 * But wait if we have a Rack timer running
5798 		 * even a SACK should not disturb us (with
5799 		 * the exception of r_rr_config 3).
5800 		 */
5801 		if ((rack->r_ctl.rc_hpts_flags & PACE_TMR_RACK) &&
5802 		    (rack->r_rr_config != 3))
5803 			inp->inp_flags2 |= INP_DONT_SACK_QUEUE;
5804 		if (rack->rc_ack_can_sendout_data) {
5805 			/*
5806 			 * Ahh but wait, this is that special case
5807 			 * where the pacing timer can be disturbed
5808 			 * backout the changes (used for non-paced
5809 			 * burst limiting).
5810 			 */
5811 			inp->inp_flags2 &= ~(INP_DONT_SACK_QUEUE|INP_MBUF_QUEUE_READY);
5812 		}
5813 		if ((rack->use_rack_rr) &&
5814 		    (rack->r_rr_config < 2) &&
5815 		    ((hpts_timeout) && (hpts_timeout < slot))) {
5816 			/*
5817 			 * Arrange for the hpts to kick back in after the
5818 			 * t-o if the t-o does not cause a send.
5819 			 */
5820 			(void)tcp_hpts_insert_diag(inp, HPTS_USEC_TO_SLOTS(hpts_timeout),
5821 						   __LINE__, &diag);
5822 			rack_log_hpts_diag(rack, us_cts, &diag, &tv);
5823 			rack_log_to_start(rack, cts, hpts_timeout, slot, 0);
5824 		} else {
5825 			(void)tcp_hpts_insert_diag(inp, HPTS_USEC_TO_SLOTS(slot),
5826 						   __LINE__, &diag);
5827 			rack_log_hpts_diag(rack, us_cts, &diag, &tv);
5828 			rack_log_to_start(rack, cts, hpts_timeout, slot, 1);
5829 		}
5830 	} else if (hpts_timeout) {
5831 		/*
5832 		 * With respect to inp_flags2 here, lets let any new acks wake
5833 		 * us up here. Since we are not pacing (no pacing timer), output
5834 		 * can happen so we should let it. If its a Rack timer, then any inbound
5835 		 * packet probably won't change the sending (we will be blocked)
5836 		 * but it may change the prr stats so letting it in (the set defaults
5837 		 * at the start of this block) are good enough.
5838 		 */
5839 		(void)tcp_hpts_insert_diag(inp, HPTS_USEC_TO_SLOTS(hpts_timeout),
5840 					   __LINE__, &diag);
5841 		rack_log_hpts_diag(rack, us_cts, &diag, &tv);
5842 		rack_log_to_start(rack, cts, hpts_timeout, slot, 0);
5843 	} else {
5844 		/* No timer starting */
5845 #ifdef INVARIANTS
5846 		if (SEQ_GT(tp->snd_max, tp->snd_una)) {
5847 			panic("tp:%p rack:%p tlts:%d cts:%u slot:%u pto:%u -- no timer started?",
5848 			    tp, rack, tot_len_this_send, cts, slot, hpts_timeout);
5849 		}
5850 #endif
5851 	}
5852 	rack->rc_tmr_stopped = 0;
5853 	if (slot)
5854 		rack_log_type_bbrsnd(rack, tot_len_this_send, slot, us_cts, &tv);
5855 }
5856 
5857 /*
5858  * RACK Timer, here we simply do logging and house keeping.
5859  * the normal rack_output() function will call the
5860  * appropriate thing to check if we need to do a RACK retransmit.
5861  * We return 1, saying don't proceed with rack_output only
5862  * when all timers have been stopped (destroyed PCB?).
5863  */
5864 static int
5865 rack_timeout_rack(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5866 {
5867 	/*
5868 	 * This timer simply provides an internal trigger to send out data.
5869 	 * The check_recovery_mode call will see if there are needed
5870 	 * retransmissions, if so we will enter fast-recovery. The output
5871 	 * call may or may not do the same thing depending on sysctl
5872 	 * settings.
5873 	 */
5874 	struct rack_sendmap *rsm;
5875 
5876 	counter_u64_add(rack_to_tot, 1);
5877 	if (rack->r_state && (rack->r_state != tp->t_state))
5878 		rack_set_state(tp, rack);
5879 	rack->rc_on_min_to = 0;
5880 	rsm = rack_check_recovery_mode(tp, cts);
5881 	rack_log_to_event(rack, RACK_TO_FRM_RACK, rsm);
5882 	if (rsm) {
5883 		rack->r_ctl.rc_resend = rsm;
5884 		rack->r_timer_override = 1;
5885 		if (rack->use_rack_rr) {
5886 			/*
5887 			 * Don't accumulate extra pacing delay
5888 			 * we are allowing the rack timer to
5889 			 * over-ride pacing i.e. rrr takes precedence
5890 			 * if the pacing interval is longer than the rrr
5891 			 * time (in other words we get the min pacing
5892 			 * time versus rrr pacing time).
5893 			 */
5894 			rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
5895 		}
5896 	}
5897 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_RACK;
5898 	if (rsm == NULL) {
5899 		/* restart a timer and return 1 */
5900 		rack_start_hpts_timer(rack, tp, cts,
5901 				      0, 0, 0);
5902 		return (1);
5903 	}
5904 	return (0);
5905 }
5906 
5907 static void
5908 rack_adjust_orig_mlen(struct rack_sendmap *rsm)
5909 {
5910 	if (rsm->m->m_len > rsm->orig_m_len) {
5911 		/*
5912 		 * Mbuf grew, caused by sbcompress, our offset does
5913 		 * not change.
5914 		 */
5915 		rsm->orig_m_len = rsm->m->m_len;
5916 	} else if (rsm->m->m_len < rsm->orig_m_len) {
5917 		/*
5918 		 * Mbuf shrank, trimmed off the top by an ack, our
5919 		 * offset changes.
5920 		 */
5921 		rsm->soff -= (rsm->orig_m_len - rsm->m->m_len);
5922 		rsm->orig_m_len = rsm->m->m_len;
5923 	}
5924 }
5925 
5926 static void
5927 rack_setup_offset_for_rsm(struct rack_sendmap *src_rsm, struct rack_sendmap *rsm)
5928 {
5929 	struct mbuf *m;
5930 	uint32_t soff;
5931 
5932 	if (src_rsm->m && (src_rsm->orig_m_len != src_rsm->m->m_len)) {
5933 		/* Fix up the orig_m_len and possibly the mbuf offset */
5934 		rack_adjust_orig_mlen(src_rsm);
5935 	}
5936 	m = src_rsm->m;
5937 	soff = src_rsm->soff + (src_rsm->r_end - src_rsm->r_start);
5938 	while (soff >= m->m_len) {
5939 		/* Move out past this mbuf */
5940 		soff -= m->m_len;
5941 		m = m->m_next;
5942 		KASSERT((m != NULL),
5943 			("rsm:%p nrsm:%p hit at soff:%u null m",
5944 			 src_rsm, rsm, soff));
5945 	}
5946 	rsm->m = m;
5947 	rsm->soff = soff;
5948 	rsm->orig_m_len = m->m_len;
5949 }
5950 
5951 static __inline void
5952 rack_clone_rsm(struct tcp_rack *rack, struct rack_sendmap *nrsm,
5953 	       struct rack_sendmap *rsm, uint32_t start)
5954 {
5955 	int idx;
5956 
5957 	nrsm->r_start = start;
5958 	nrsm->r_end = rsm->r_end;
5959 	nrsm->r_rtr_cnt = rsm->r_rtr_cnt;
5960 	nrsm->r_flags = rsm->r_flags;
5961 	nrsm->r_dupack = rsm->r_dupack;
5962 	nrsm->r_no_rtt_allowed = rsm->r_no_rtt_allowed;
5963 	nrsm->r_rtr_bytes = 0;
5964 	nrsm->r_fas = rsm->r_fas;
5965 	rsm->r_end = nrsm->r_start;
5966 	nrsm->r_just_ret = rsm->r_just_ret;
5967 	for (idx = 0; idx < nrsm->r_rtr_cnt; idx++) {
5968 		nrsm->r_tim_lastsent[idx] = rsm->r_tim_lastsent[idx];
5969 	}
5970 	/* Now if we have SYN flag we keep it on the left edge */
5971 	if (nrsm->r_flags & RACK_HAS_SYN)
5972 		nrsm->r_flags &= ~RACK_HAS_SYN;
5973 	/* Now if we have a FIN flag we keep it on the right edge */
5974 	if (rsm->r_flags & RACK_HAS_FIN)
5975 		rsm->r_flags &= ~RACK_HAS_FIN;
5976 	/* Push bit must go to the right edge as well */
5977 	if (rsm->r_flags & RACK_HAD_PUSH)
5978 		rsm->r_flags &= ~RACK_HAD_PUSH;
5979 	/* Clone over the state of the hw_tls flag */
5980 	nrsm->r_hw_tls = rsm->r_hw_tls;
5981 	/*
5982 	 * Now we need to find nrsm's new location in the mbuf chain
5983 	 * we basically calculate a new offset, which is soff +
5984 	 * how much is left in original rsm. Then we walk out the mbuf
5985 	 * chain to find the righ position, it may be the same mbuf
5986 	 * or maybe not.
5987 	 */
5988 	KASSERT(((rsm->m != NULL) ||
5989 		 (rsm->r_flags & (RACK_HAS_SYN|RACK_HAS_FIN))),
5990 		("rsm:%p nrsm:%p rack:%p -- rsm->m is NULL?", rsm, nrsm, rack));
5991 	if (rsm->m)
5992 		rack_setup_offset_for_rsm(rsm, nrsm);
5993 }
5994 
5995 static struct rack_sendmap *
5996 rack_merge_rsm(struct tcp_rack *rack,
5997 	       struct rack_sendmap *l_rsm,
5998 	       struct rack_sendmap *r_rsm)
5999 {
6000 	/*
6001 	 * We are merging two ack'd RSM's,
6002 	 * the l_rsm is on the left (lower seq
6003 	 * values) and the r_rsm is on the right
6004 	 * (higher seq value). The simplest way
6005 	 * to merge these is to move the right
6006 	 * one into the left. I don't think there
6007 	 * is any reason we need to try to find
6008 	 * the oldest (or last oldest retransmitted).
6009 	 */
6010 #ifdef INVARIANTS
6011 	struct rack_sendmap *rm;
6012 #endif
6013 	rack_log_map_chg(rack->rc_tp, rack, NULL,
6014 			 l_rsm, r_rsm, MAP_MERGE, r_rsm->r_end, __LINE__);
6015 	l_rsm->r_end = r_rsm->r_end;
6016 	if (l_rsm->r_dupack < r_rsm->r_dupack)
6017 		l_rsm->r_dupack = r_rsm->r_dupack;
6018 	if (r_rsm->r_rtr_bytes)
6019 		l_rsm->r_rtr_bytes += r_rsm->r_rtr_bytes;
6020 	if (r_rsm->r_in_tmap) {
6021 		/* This really should not happen */
6022 		TAILQ_REMOVE(&rack->r_ctl.rc_tmap, r_rsm, r_tnext);
6023 		r_rsm->r_in_tmap = 0;
6024 	}
6025 
6026 	/* Now the flags */
6027 	if (r_rsm->r_flags & RACK_HAS_FIN)
6028 		l_rsm->r_flags |= RACK_HAS_FIN;
6029 	if (r_rsm->r_flags & RACK_TLP)
6030 		l_rsm->r_flags |= RACK_TLP;
6031 	if (r_rsm->r_flags & RACK_RWND_COLLAPSED)
6032 		l_rsm->r_flags |= RACK_RWND_COLLAPSED;
6033 	if ((r_rsm->r_flags & RACK_APP_LIMITED)  &&
6034 	    ((l_rsm->r_flags & RACK_APP_LIMITED) == 0)) {
6035 		/*
6036 		 * If both are app-limited then let the
6037 		 * free lower the count. If right is app
6038 		 * limited and left is not, transfer.
6039 		 */
6040 		l_rsm->r_flags |= RACK_APP_LIMITED;
6041 		r_rsm->r_flags &= ~RACK_APP_LIMITED;
6042 		if (r_rsm == rack->r_ctl.rc_first_appl)
6043 			rack->r_ctl.rc_first_appl = l_rsm;
6044 	}
6045 #ifndef INVARIANTS
6046 	(void)RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, r_rsm);
6047 #else
6048 	rm = RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, r_rsm);
6049 	if (rm != r_rsm) {
6050 		panic("removing head in rack:%p rsm:%p rm:%p",
6051 		      rack, r_rsm, rm);
6052 	}
6053 #endif
6054 	if ((r_rsm->r_limit_type == 0) && (l_rsm->r_limit_type != 0)) {
6055 		/* Transfer the split limit to the map we free */
6056 		r_rsm->r_limit_type = l_rsm->r_limit_type;
6057 		l_rsm->r_limit_type = 0;
6058 	}
6059 	rack_free(rack, r_rsm);
6060 	return (l_rsm);
6061 }
6062 
6063 /*
6064  * TLP Timer, here we simply setup what segment we want to
6065  * have the TLP expire on, the normal rack_output() will then
6066  * send it out.
6067  *
6068  * We return 1, saying don't proceed with rack_output only
6069  * when all timers have been stopped (destroyed PCB?).
6070  */
6071 static int
6072 rack_timeout_tlp(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, uint8_t *doing_tlp)
6073 {
6074 	/*
6075 	 * Tail Loss Probe.
6076 	 */
6077 	struct rack_sendmap *rsm = NULL;
6078 #ifdef INVARIANTS
6079 	struct rack_sendmap *insret;
6080 #endif
6081 	struct socket *so = tptosocket(tp);
6082 	uint32_t amm;
6083 	uint32_t out, avail;
6084 	int collapsed_win = 0;
6085 
6086 	if (TSTMP_LT(cts, rack->r_ctl.rc_timer_exp)) {
6087 		/* Its not time yet */
6088 		return (0);
6089 	}
6090 	if (ctf_progress_timeout_check(tp, true)) {
6091 		rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
6092 		return (-ETIMEDOUT);	/* tcp_drop() */
6093 	}
6094 	/*
6095 	 * A TLP timer has expired. We have been idle for 2 rtts. So we now
6096 	 * need to figure out how to force a full MSS segment out.
6097 	 */
6098 	rack_log_to_event(rack, RACK_TO_FRM_TLP, NULL);
6099 	rack->r_ctl.retran_during_recovery = 0;
6100 	rack->r_ctl.dsack_byte_cnt = 0;
6101 	counter_u64_add(rack_tlp_tot, 1);
6102 	if (rack->r_state && (rack->r_state != tp->t_state))
6103 		rack_set_state(tp, rack);
6104 	avail = sbavail(&so->so_snd);
6105 	out = tp->snd_max - tp->snd_una;
6106 	if ((out > tp->snd_wnd) || rack->rc_has_collapsed) {
6107 		/* special case, we need a retransmission */
6108 		collapsed_win = 1;
6109 		goto need_retran;
6110 	}
6111 	if (rack->r_ctl.dsack_persist && (rack->r_ctl.rc_tlp_cnt_out >= 1)) {
6112 		rack->r_ctl.dsack_persist--;
6113 		if (rack->r_ctl.num_dsack && (rack->r_ctl.dsack_persist == 0)) {
6114 			rack->r_ctl.num_dsack = 0;
6115 		}
6116 		rack_log_dsack_event(rack, 1, __LINE__, 0, 0);
6117 	}
6118 	if ((tp->t_flags & TF_GPUTINPROG) &&
6119 	    (rack->r_ctl.rc_tlp_cnt_out == 1)) {
6120 		/*
6121 		 * If this is the second in a row
6122 		 * TLP and we are doing a measurement
6123 		 * its time to abandon the measurement.
6124 		 * Something is likely broken on
6125 		 * the clients network and measuring a
6126 		 * broken network does us no good.
6127 		 */
6128 		tp->t_flags &= ~TF_GPUTINPROG;
6129 		rack_log_pacing_delay_calc(rack, (tp->gput_ack - tp->gput_seq) /*flex2*/,
6130 					   rack->r_ctl.rc_gp_srtt /*flex1*/,
6131 					   tp->gput_seq,
6132 					   0, 0, 18, __LINE__, NULL, 0);
6133 	}
6134 	/*
6135 	 * Check our send oldest always settings, and if
6136 	 * there is an oldest to send jump to the need_retran.
6137 	 */
6138 	if (rack_always_send_oldest && (TAILQ_EMPTY(&rack->r_ctl.rc_tmap) == 0))
6139 		goto need_retran;
6140 
6141 	if (avail > out) {
6142 		/* New data is available */
6143 		amm = avail - out;
6144 		if (amm > ctf_fixed_maxseg(tp)) {
6145 			amm = ctf_fixed_maxseg(tp);
6146 			if ((amm + out) > tp->snd_wnd) {
6147 				/* We are rwnd limited */
6148 				goto need_retran;
6149 			}
6150 		} else if (amm < ctf_fixed_maxseg(tp)) {
6151 			/* not enough to fill a MTU */
6152 			goto need_retran;
6153 		}
6154 		if (IN_FASTRECOVERY(tp->t_flags)) {
6155 			/* Unlikely */
6156 			if (rack->rack_no_prr == 0) {
6157 				if (out + amm <= tp->snd_wnd) {
6158 					rack->r_ctl.rc_prr_sndcnt = amm;
6159 					rack->r_ctl.rc_tlp_new_data = amm;
6160 					rack_log_to_prr(rack, 4, 0, __LINE__);
6161 				}
6162 			} else
6163 				goto need_retran;
6164 		} else {
6165 			/* Set the send-new override */
6166 			if (out + amm <= tp->snd_wnd)
6167 				rack->r_ctl.rc_tlp_new_data = amm;
6168 			else
6169 				goto need_retran;
6170 		}
6171 		rack->r_ctl.rc_tlpsend = NULL;
6172 		counter_u64_add(rack_tlp_newdata, 1);
6173 		goto send;
6174 	}
6175 need_retran:
6176 	/*
6177 	 * Ok we need to arrange the last un-acked segment to be re-sent, or
6178 	 * optionally the first un-acked segment.
6179 	 */
6180 	if (collapsed_win == 0) {
6181 		if (rack_always_send_oldest)
6182 			rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
6183 		else {
6184 			rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
6185 			if (rsm && (rsm->r_flags & (RACK_ACKED | RACK_HAS_FIN))) {
6186 				rsm = rack_find_high_nonack(rack, rsm);
6187 			}
6188 		}
6189 		if (rsm == NULL) {
6190 #ifdef TCP_BLACKBOX
6191 			tcp_log_dump_tp_logbuf(tp, "nada counter trips", M_NOWAIT, true);
6192 #endif
6193 			goto out;
6194 		}
6195 	} else {
6196 		/*
6197 		 * We must find the last segment
6198 		 * that was acceptable by the client.
6199 		 */
6200 		RB_FOREACH_REVERSE(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
6201 			if ((rsm->r_flags & RACK_RWND_COLLAPSED) == 0) {
6202 				/* Found one */
6203 				break;
6204 			}
6205 		}
6206 		if (rsm == NULL) {
6207 			/* None? if so send the first */
6208 			rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
6209 			if (rsm == NULL) {
6210 #ifdef TCP_BLACKBOX
6211 				tcp_log_dump_tp_logbuf(tp, "nada counter trips", M_NOWAIT, true);
6212 #endif
6213 				goto out;
6214 			}
6215 		}
6216 	}
6217 	if ((rsm->r_end - rsm->r_start) > ctf_fixed_maxseg(tp)) {
6218 		/*
6219 		 * We need to split this the last segment in two.
6220 		 */
6221 		struct rack_sendmap *nrsm;
6222 
6223 		nrsm = rack_alloc_full_limit(rack);
6224 		if (nrsm == NULL) {
6225 			/*
6226 			 * No memory to split, we will just exit and punt
6227 			 * off to the RXT timer.
6228 			 */
6229 			goto out;
6230 		}
6231 		rack_clone_rsm(rack, nrsm, rsm,
6232 			       (rsm->r_end - ctf_fixed_maxseg(tp)));
6233 		rack_log_map_chg(tp, rack, NULL, rsm, nrsm, MAP_SPLIT, 0, __LINE__);
6234 #ifndef INVARIANTS
6235 		(void)RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
6236 #else
6237 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
6238 		if (insret != NULL) {
6239 			panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
6240 			      nrsm, insret, rack, rsm);
6241 		}
6242 #endif
6243 		if (rsm->r_in_tmap) {
6244 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
6245 			nrsm->r_in_tmap = 1;
6246 		}
6247 		rsm = nrsm;
6248 	}
6249 	rack->r_ctl.rc_tlpsend = rsm;
6250 send:
6251 	/* Make sure output path knows we are doing a TLP */
6252 	*doing_tlp = 1;
6253 	rack->r_timer_override = 1;
6254 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_TLP;
6255 	return (0);
6256 out:
6257 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_TLP;
6258 	return (0);
6259 }
6260 
6261 /*
6262  * Delayed ack Timer, here we simply need to setup the
6263  * ACK_NOW flag and remove the DELACK flag. From there
6264  * the output routine will send the ack out.
6265  *
6266  * We only return 1, saying don't proceed, if all timers
6267  * are stopped (destroyed PCB?).
6268  */
6269 static int
6270 rack_timeout_delack(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
6271 {
6272 
6273 	rack_log_to_event(rack, RACK_TO_FRM_DELACK, NULL);
6274 	tp->t_flags &= ~TF_DELACK;
6275 	tp->t_flags |= TF_ACKNOW;
6276 	KMOD_TCPSTAT_INC(tcps_delack);
6277 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_DELACK;
6278 	return (0);
6279 }
6280 
6281 /*
6282  * Persists timer, here we simply send the
6283  * same thing as a keepalive will.
6284  * the one byte send.
6285  *
6286  * We only return 1, saying don't proceed, if all timers
6287  * are stopped (destroyed PCB?).
6288  */
6289 static int
6290 rack_timeout_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
6291 {
6292 	struct tcptemp *t_template;
6293 	int32_t retval = 1;
6294 
6295 	if (rack->rc_in_persist == 0)
6296 		return (0);
6297 	if (ctf_progress_timeout_check(tp, false)) {
6298 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
6299 		rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
6300 		counter_u64_add(rack_persists_lost_ends, rack->r_ctl.persist_lost_ends);
6301 		return (-ETIMEDOUT);	/* tcp_drop() */
6302 	}
6303 	/*
6304 	 * Persistence timer into zero window. Force a byte to be output, if
6305 	 * possible.
6306 	 */
6307 	KMOD_TCPSTAT_INC(tcps_persisttimeo);
6308 	/*
6309 	 * Hack: if the peer is dead/unreachable, we do not time out if the
6310 	 * window is closed.  After a full backoff, drop the connection if
6311 	 * the idle time (no responses to probes) reaches the maximum
6312 	 * backoff that we would use if retransmitting.
6313 	 */
6314 	if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
6315 	    (ticks - tp->t_rcvtime >= tcp_maxpersistidle ||
6316 	     TICKS_2_USEC(ticks - tp->t_rcvtime) >= RACK_REXMTVAL(tp) * tcp_totbackoff)) {
6317 		KMOD_TCPSTAT_INC(tcps_persistdrop);
6318 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
6319 		counter_u64_add(rack_persists_lost_ends, rack->r_ctl.persist_lost_ends);
6320 		retval = -ETIMEDOUT;	/* tcp_drop() */
6321 		goto out;
6322 	}
6323 	if ((sbavail(&rack->rc_inp->inp_socket->so_snd) == 0) &&
6324 	    tp->snd_una == tp->snd_max)
6325 		rack_exit_persist(tp, rack, cts);
6326 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_PERSIT;
6327 	/*
6328 	 * If the user has closed the socket then drop a persisting
6329 	 * connection after a much reduced timeout.
6330 	 */
6331 	if (tp->t_state > TCPS_CLOSE_WAIT &&
6332 	    (ticks - tp->t_rcvtime) >= TCPTV_PERSMAX) {
6333 		KMOD_TCPSTAT_INC(tcps_persistdrop);
6334 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
6335 		counter_u64_add(rack_persists_lost_ends, rack->r_ctl.persist_lost_ends);
6336 		retval = -ETIMEDOUT;	/* tcp_drop() */
6337 		goto out;
6338 	}
6339 	t_template = tcpip_maketemplate(rack->rc_inp);
6340 	if (t_template) {
6341 		/* only set it if we were answered */
6342 		if (rack->forced_ack == 0) {
6343 			rack->forced_ack = 1;
6344 			rack->r_ctl.forced_ack_ts = tcp_get_usecs(NULL);
6345 		} else {
6346 			rack->probe_not_answered = 1;
6347 			counter_u64_add(rack_persists_loss, 1);
6348 			rack->r_ctl.persist_lost_ends++;
6349 		}
6350 		counter_u64_add(rack_persists_sends, 1);
6351 		tcp_respond(tp, t_template->tt_ipgen,
6352 			    &t_template->tt_t, (struct mbuf *)NULL,
6353 			    tp->rcv_nxt, tp->snd_una - 1, 0);
6354 		/* This sends an ack */
6355 		if (tp->t_flags & TF_DELACK)
6356 			tp->t_flags &= ~TF_DELACK;
6357 		free(t_template, M_TEMP);
6358 	}
6359 	if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
6360 		tp->t_rxtshift++;
6361 out:
6362 	rack_log_to_event(rack, RACK_TO_FRM_PERSIST, NULL);
6363 	rack_start_hpts_timer(rack, tp, cts,
6364 			      0, 0, 0);
6365 	return (retval);
6366 }
6367 
6368 /*
6369  * If a keepalive goes off, we had no other timers
6370  * happening. We always return 1 here since this
6371  * routine either drops the connection or sends
6372  * out a segment with respond.
6373  */
6374 static int
6375 rack_timeout_keepalive(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
6376 {
6377 	struct tcptemp *t_template;
6378 	struct inpcb *inp = tptoinpcb(tp);
6379 
6380 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_KEEP;
6381 	rack_log_to_event(rack, RACK_TO_FRM_KEEP, NULL);
6382 	/*
6383 	 * Keep-alive timer went off; send something or drop connection if
6384 	 * idle for too long.
6385 	 */
6386 	KMOD_TCPSTAT_INC(tcps_keeptimeo);
6387 	if (tp->t_state < TCPS_ESTABLISHED)
6388 		goto dropit;
6389 	if ((V_tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
6390 	    tp->t_state <= TCPS_CLOSING) {
6391 		if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp))
6392 			goto dropit;
6393 		/*
6394 		 * Send a packet designed to force a response if the peer is
6395 		 * up and reachable: either an ACK if the connection is
6396 		 * still alive, or an RST if the peer has closed the
6397 		 * connection due to timeout or reboot. Using sequence
6398 		 * number tp->snd_una-1 causes the transmitted zero-length
6399 		 * segment to lie outside the receive window; by the
6400 		 * protocol spec, this requires the correspondent TCP to
6401 		 * respond.
6402 		 */
6403 		KMOD_TCPSTAT_INC(tcps_keepprobe);
6404 		t_template = tcpip_maketemplate(inp);
6405 		if (t_template) {
6406 			if (rack->forced_ack == 0) {
6407 				rack->forced_ack = 1;
6408 				rack->r_ctl.forced_ack_ts = tcp_get_usecs(NULL);
6409 			} else {
6410 				rack->probe_not_answered = 1;
6411 			}
6412 			tcp_respond(tp, t_template->tt_ipgen,
6413 			    &t_template->tt_t, (struct mbuf *)NULL,
6414 			    tp->rcv_nxt, tp->snd_una - 1, 0);
6415 			free(t_template, M_TEMP);
6416 		}
6417 	}
6418 	rack_start_hpts_timer(rack, tp, cts, 0, 0, 0);
6419 	return (1);
6420 dropit:
6421 	KMOD_TCPSTAT_INC(tcps_keepdrops);
6422 	tcp_log_end_status(tp, TCP_EI_STATUS_KEEP_MAX);
6423 	return (-ETIMEDOUT);	/* tcp_drop() */
6424 }
6425 
6426 /*
6427  * Retransmit helper function, clear up all the ack
6428  * flags and take care of important book keeping.
6429  */
6430 static void
6431 rack_remxt_tmr(struct tcpcb *tp)
6432 {
6433 	/*
6434 	 * The retransmit timer went off, all sack'd blocks must be
6435 	 * un-acked.
6436 	 */
6437 	struct rack_sendmap *rsm, *trsm = NULL;
6438 	struct tcp_rack *rack;
6439 
6440 	rack = (struct tcp_rack *)tp->t_fb_ptr;
6441 	rack_timer_cancel(tp, rack, tcp_get_usecs(NULL), __LINE__);
6442 	rack_log_to_event(rack, RACK_TO_FRM_TMR, NULL);
6443 	if (rack->r_state && (rack->r_state != tp->t_state))
6444 		rack_set_state(tp, rack);
6445 	/*
6446 	 * Ideally we would like to be able to
6447 	 * mark SACK-PASS on anything not acked here.
6448 	 *
6449 	 * However, if we do that we would burst out
6450 	 * all that data 1ms apart. This would be unwise,
6451 	 * so for now we will just let the normal rxt timer
6452 	 * and tlp timer take care of it.
6453 	 *
6454 	 * Also we really need to stick them back in sequence
6455 	 * order. This way we send in the proper order and any
6456 	 * sacks that come floating in will "re-ack" the data.
6457 	 * To do this we zap the tmap with an INIT and then
6458 	 * walk through and place every rsm in the RB tree
6459 	 * back in its seq ordered place.
6460 	 */
6461 	TAILQ_INIT(&rack->r_ctl.rc_tmap);
6462 	RB_FOREACH(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
6463 		rsm->r_dupack = 0;
6464 		rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
6465 		/* We must re-add it back to the tlist */
6466 		if (trsm == NULL) {
6467 			TAILQ_INSERT_HEAD(&rack->r_ctl.rc_tmap, rsm, r_tnext);
6468 		} else {
6469 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, trsm, rsm, r_tnext);
6470 		}
6471 		rsm->r_in_tmap = 1;
6472 		trsm = rsm;
6473 		if (rsm->r_flags & RACK_ACKED)
6474 			rsm->r_flags |= RACK_WAS_ACKED;
6475 		rsm->r_flags &= ~(RACK_ACKED | RACK_SACK_PASSED | RACK_WAS_SACKPASS | RACK_RWND_COLLAPSED);
6476 		rsm->r_flags |= RACK_MUST_RXT;
6477 	}
6478 	/* Clear the count (we just un-acked them) */
6479 	rack->r_ctl.rc_last_timeout_snduna = tp->snd_una;
6480 	rack->r_ctl.rc_sacked = 0;
6481 	rack->r_ctl.rc_sacklast = NULL;
6482 	rack->r_ctl.rc_agg_delayed = 0;
6483 	rack->r_early = 0;
6484 	rack->r_ctl.rc_agg_early = 0;
6485 	rack->r_late = 0;
6486 	/* Clear the tlp rtx mark */
6487 	rack->r_ctl.rc_resend = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
6488 	if (rack->r_ctl.rc_resend != NULL)
6489 		rack->r_ctl.rc_resend->r_flags |= RACK_TO_REXT;
6490 	rack->r_ctl.rc_prr_sndcnt = 0;
6491 	rack_log_to_prr(rack, 6, 0, __LINE__);
6492 	rack->r_timer_override = 1;
6493 	if ((((tp->t_flags & TF_SACK_PERMIT) == 0)
6494 #ifdef NETFLIX_EXP_DETECTION
6495 	    || (rack->sack_attack_disable != 0)
6496 #endif
6497 		    ) && ((tp->t_flags & TF_SENTFIN) == 0)) {
6498 		/*
6499 		 * For non-sack customers new data
6500 		 * needs to go out as retransmits until
6501 		 * we retransmit up to snd_max.
6502 		 */
6503 		rack->r_must_retran = 1;
6504 		rack->r_ctl.rc_out_at_rto = ctf_flight_size(rack->rc_tp,
6505 						rack->r_ctl.rc_sacked);
6506 	}
6507 	rack->r_ctl.rc_snd_max_at_rto = tp->snd_max;
6508 }
6509 
6510 static void
6511 rack_convert_rtts(struct tcpcb *tp)
6512 {
6513 	if (tp->t_srtt > 1) {
6514 		uint32_t val, frac;
6515 
6516 		val = tp->t_srtt >> TCP_RTT_SHIFT;
6517 		frac = tp->t_srtt & 0x1f;
6518 		tp->t_srtt = TICKS_2_USEC(val);
6519 		/*
6520 		 * frac is the fractional part of the srtt (if any)
6521 		 * but its in ticks and every bit represents
6522 		 * 1/32nd of a hz.
6523 		 */
6524 		if (frac) {
6525 			if (hz == 1000) {
6526 				frac = (((uint64_t)frac * (uint64_t)HPTS_USEC_IN_MSEC) / (uint64_t)TCP_RTT_SCALE);
6527 			} else {
6528 				frac = (((uint64_t)frac * (uint64_t)HPTS_USEC_IN_SEC) / ((uint64_t)(hz) * (uint64_t)TCP_RTT_SCALE));
6529 			}
6530 			tp->t_srtt += frac;
6531 		}
6532 	}
6533 	if (tp->t_rttvar) {
6534 		uint32_t val, frac;
6535 
6536 		val = tp->t_rttvar >> TCP_RTTVAR_SHIFT;
6537 		frac = tp->t_rttvar & 0x1f;
6538 		tp->t_rttvar = TICKS_2_USEC(val);
6539 		/*
6540 		 * frac is the fractional part of the srtt (if any)
6541 		 * but its in ticks and every bit represents
6542 		 * 1/32nd of a hz.
6543 		 */
6544 		if (frac) {
6545 			if (hz == 1000) {
6546 				frac = (((uint64_t)frac * (uint64_t)HPTS_USEC_IN_MSEC) / (uint64_t)TCP_RTT_SCALE);
6547 			} else {
6548 				frac = (((uint64_t)frac * (uint64_t)HPTS_USEC_IN_SEC) / ((uint64_t)(hz) * (uint64_t)TCP_RTT_SCALE));
6549 			}
6550 			tp->t_rttvar += frac;
6551 		}
6552 	}
6553 	tp->t_rxtcur = RACK_REXMTVAL(tp);
6554 	if (TCPS_HAVEESTABLISHED(tp->t_state)) {
6555 		tp->t_rxtcur += TICKS_2_USEC(tcp_rexmit_slop);
6556 	}
6557 	if (tp->t_rxtcur > rack_rto_max) {
6558 		tp->t_rxtcur = rack_rto_max;
6559 	}
6560 }
6561 
6562 static void
6563 rack_cc_conn_init(struct tcpcb *tp)
6564 {
6565 	struct tcp_rack *rack;
6566 	uint32_t srtt;
6567 
6568 	rack = (struct tcp_rack *)tp->t_fb_ptr;
6569 	srtt = tp->t_srtt;
6570 	cc_conn_init(tp);
6571 	/*
6572 	 * Now convert to rack's internal format,
6573 	 * if required.
6574 	 */
6575 	if ((srtt == 0) && (tp->t_srtt != 0))
6576 		rack_convert_rtts(tp);
6577 	/*
6578 	 * We want a chance to stay in slowstart as
6579 	 * we create a connection. TCP spec says that
6580 	 * initially ssthresh is infinite. For our
6581 	 * purposes that is the snd_wnd.
6582 	 */
6583 	if (tp->snd_ssthresh < tp->snd_wnd) {
6584 		tp->snd_ssthresh = tp->snd_wnd;
6585 	}
6586 	/*
6587 	 * We also want to assure a IW worth of
6588 	 * data can get inflight.
6589 	 */
6590 	if (rc_init_window(rack) < tp->snd_cwnd)
6591 		tp->snd_cwnd = rc_init_window(rack);
6592 }
6593 
6594 /*
6595  * Re-transmit timeout! If we drop the PCB we will return 1, otherwise
6596  * we will setup to retransmit the lowest seq number outstanding.
6597  */
6598 static int
6599 rack_timeout_rxt(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
6600 {
6601 	struct inpcb *inp = tptoinpcb(tp);
6602 	int32_t rexmt;
6603 	int32_t retval = 0;
6604 	bool isipv6;
6605 
6606 	if ((tp->t_flags & TF_GPUTINPROG) &&
6607 	    (tp->t_rxtshift)) {
6608 		/*
6609 		 * We have had a second timeout
6610 		 * measurements on successive rxt's are not profitable.
6611 		 * It is unlikely to be of any use (the network is
6612 		 * broken or the client went away).
6613 		 */
6614 		tp->t_flags &= ~TF_GPUTINPROG;
6615 		rack_log_pacing_delay_calc(rack, (tp->gput_ack - tp->gput_seq) /*flex2*/,
6616 					   rack->r_ctl.rc_gp_srtt /*flex1*/,
6617 					   tp->gput_seq,
6618 					   0, 0, 18, __LINE__, NULL, 0);
6619 	}
6620 	if (ctf_progress_timeout_check(tp, false)) {
6621 		tcp_log_end_status(tp, TCP_EI_STATUS_RETRAN);
6622 		rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
6623 		return (-ETIMEDOUT);	/* tcp_drop() */
6624 	}
6625 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_RXT;
6626 	rack->r_ctl.retran_during_recovery = 0;
6627 	rack->rc_ack_required = 1;
6628 	rack->r_ctl.dsack_byte_cnt = 0;
6629 	if (IN_FASTRECOVERY(tp->t_flags))
6630 		tp->t_flags |= TF_WASFRECOVERY;
6631 	else
6632 		tp->t_flags &= ~TF_WASFRECOVERY;
6633 	if (IN_CONGRECOVERY(tp->t_flags))
6634 		tp->t_flags |= TF_WASCRECOVERY;
6635 	else
6636 		tp->t_flags &= ~TF_WASCRECOVERY;
6637 	if (TCPS_HAVEESTABLISHED(tp->t_state) &&
6638 	    (tp->snd_una == tp->snd_max)) {
6639 		/* Nothing outstanding .. nothing to do */
6640 		return (0);
6641 	}
6642 	if (rack->r_ctl.dsack_persist) {
6643 		rack->r_ctl.dsack_persist--;
6644 		if (rack->r_ctl.num_dsack && (rack->r_ctl.dsack_persist == 0)) {
6645 			rack->r_ctl.num_dsack = 0;
6646 		}
6647 		rack_log_dsack_event(rack, 1, __LINE__, 0, 0);
6648 	}
6649 	/*
6650 	 * Rack can only run one timer  at a time, so we cannot
6651 	 * run a KEEPINIT (gating SYN sending) and a retransmit
6652 	 * timer for the SYN. So if we are in a front state and
6653 	 * have a KEEPINIT timer we need to check the first transmit
6654 	 * against now to see if we have exceeded the KEEPINIT time
6655 	 * (if one is set).
6656 	 */
6657 	if ((TCPS_HAVEESTABLISHED(tp->t_state) == 0) &&
6658 	    (TP_KEEPINIT(tp) != 0)) {
6659 		struct rack_sendmap *rsm;
6660 
6661 		rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
6662 		if (rsm) {
6663 			/* Ok we have something outstanding to test keepinit with */
6664 			if ((TSTMP_GT(cts, (uint32_t)rsm->r_tim_lastsent[0])) &&
6665 			    ((cts - (uint32_t)rsm->r_tim_lastsent[0]) >= TICKS_2_USEC(TP_KEEPINIT(tp)))) {
6666 				/* We have exceeded the KEEPINIT time */
6667 				tcp_log_end_status(tp, TCP_EI_STATUS_KEEP_MAX);
6668 				goto drop_it;
6669 			}
6670 		}
6671 	}
6672 	/*
6673 	 * Retransmission timer went off.  Message has not been acked within
6674 	 * retransmit interval.  Back off to a longer retransmit interval
6675 	 * and retransmit one segment.
6676 	 */
6677 	rack_remxt_tmr(tp);
6678 	if ((rack->r_ctl.rc_resend == NULL) ||
6679 	    ((rack->r_ctl.rc_resend->r_flags & RACK_RWND_COLLAPSED) == 0)) {
6680 		/*
6681 		 * If the rwnd collapsed on
6682 		 * the one we are retransmitting
6683 		 * it does not count against the
6684 		 * rxt count.
6685 		 */
6686 		tp->t_rxtshift++;
6687 	}
6688 	if (tp->t_rxtshift > TCP_MAXRXTSHIFT) {
6689 		tcp_log_end_status(tp, TCP_EI_STATUS_RETRAN);
6690 drop_it:
6691 		tp->t_rxtshift = TCP_MAXRXTSHIFT;
6692 		KMOD_TCPSTAT_INC(tcps_timeoutdrop);
6693 		/* XXXGL: previously t_softerror was casted to uint16_t */
6694 		MPASS(tp->t_softerror >= 0);
6695 		retval = tp->t_softerror ? -tp->t_softerror : -ETIMEDOUT;
6696 		goto out;	/* tcp_drop() */
6697 	}
6698 	if (tp->t_state == TCPS_SYN_SENT) {
6699 		/*
6700 		 * If the SYN was retransmitted, indicate CWND to be limited
6701 		 * to 1 segment in cc_conn_init().
6702 		 */
6703 		tp->snd_cwnd = 1;
6704 	} else if (tp->t_rxtshift == 1) {
6705 		/*
6706 		 * first retransmit; record ssthresh and cwnd so they can be
6707 		 * recovered if this turns out to be a "bad" retransmit. A
6708 		 * retransmit is considered "bad" if an ACK for this segment
6709 		 * is received within RTT/2 interval; the assumption here is
6710 		 * that the ACK was already in flight.  See "On Estimating
6711 		 * End-to-End Network Path Properties" by Allman and Paxson
6712 		 * for more details.
6713 		 */
6714 		tp->snd_cwnd_prev = tp->snd_cwnd;
6715 		tp->snd_ssthresh_prev = tp->snd_ssthresh;
6716 		tp->snd_recover_prev = tp->snd_recover;
6717 		tp->t_badrxtwin = ticks + (USEC_2_TICKS(tp->t_srtt)/2);
6718 		tp->t_flags |= TF_PREVVALID;
6719 	} else if ((tp->t_flags & TF_RCVD_TSTMP) == 0)
6720 		tp->t_flags &= ~TF_PREVVALID;
6721 	KMOD_TCPSTAT_INC(tcps_rexmttimeo);
6722 	if ((tp->t_state == TCPS_SYN_SENT) ||
6723 	    (tp->t_state == TCPS_SYN_RECEIVED))
6724 		rexmt = RACK_INITIAL_RTO * tcp_backoff[tp->t_rxtshift];
6725 	else
6726 		rexmt = max(rack_rto_min, (tp->t_srtt + (tp->t_rttvar << 2))) * tcp_backoff[tp->t_rxtshift];
6727 
6728 	RACK_TCPT_RANGESET(tp->t_rxtcur, rexmt,
6729 	   max(rack_rto_min, rexmt), rack_rto_max, rack->r_ctl.timer_slop);
6730 	/*
6731 	 * We enter the path for PLMTUD if connection is established or, if
6732 	 * connection is FIN_WAIT_1 status, reason for the last is that if
6733 	 * amount of data we send is very small, we could send it in couple
6734 	 * of packets and process straight to FIN. In that case we won't
6735 	 * catch ESTABLISHED state.
6736 	 */
6737 #ifdef INET6
6738 	isipv6 = (inp->inp_vflag & INP_IPV6) ? true : false;
6739 #else
6740 	isipv6 = false;
6741 #endif
6742 	if (((V_tcp_pmtud_blackhole_detect == 1) ||
6743 	    (V_tcp_pmtud_blackhole_detect == 2 && !isipv6) ||
6744 	    (V_tcp_pmtud_blackhole_detect == 3 && isipv6)) &&
6745 	    ((tp->t_state == TCPS_ESTABLISHED) ||
6746 	    (tp->t_state == TCPS_FIN_WAIT_1))) {
6747 		/*
6748 		 * Idea here is that at each stage of mtu probe (usually,
6749 		 * 1448 -> 1188 -> 524) should be given 2 chances to recover
6750 		 * before further clamping down. 'tp->t_rxtshift % 2 == 0'
6751 		 * should take care of that.
6752 		 */
6753 		if (((tp->t_flags2 & (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) ==
6754 		    (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) &&
6755 		    (tp->t_rxtshift >= 2 && tp->t_rxtshift < 6 &&
6756 		    tp->t_rxtshift % 2 == 0)) {
6757 			/*
6758 			 * Enter Path MTU Black-hole Detection mechanism: -
6759 			 * Disable Path MTU Discovery (IP "DF" bit). -
6760 			 * Reduce MTU to lower value than what we negotiated
6761 			 * with peer.
6762 			 */
6763 			if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) == 0) {
6764 				/* Record that we may have found a black hole. */
6765 				tp->t_flags2 |= TF2_PLPMTU_BLACKHOLE;
6766 				/* Keep track of previous MSS. */
6767 				tp->t_pmtud_saved_maxseg = tp->t_maxseg;
6768 			}
6769 
6770 			/*
6771 			 * Reduce the MSS to blackhole value or to the
6772 			 * default in an attempt to retransmit.
6773 			 */
6774 #ifdef INET6
6775 			if (isipv6 &&
6776 			    tp->t_maxseg > V_tcp_v6pmtud_blackhole_mss) {
6777 				/* Use the sysctl tuneable blackhole MSS. */
6778 				tp->t_maxseg = V_tcp_v6pmtud_blackhole_mss;
6779 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated);
6780 			} else if (isipv6) {
6781 				/* Use the default MSS. */
6782 				tp->t_maxseg = V_tcp_v6mssdflt;
6783 				/*
6784 				 * Disable Path MTU Discovery when we switch
6785 				 * to minmss.
6786 				 */
6787 				tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
6788 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
6789 			}
6790 #endif
6791 #if defined(INET6) && defined(INET)
6792 			else
6793 #endif
6794 #ifdef INET
6795 			if (tp->t_maxseg > V_tcp_pmtud_blackhole_mss) {
6796 				/* Use the sysctl tuneable blackhole MSS. */
6797 				tp->t_maxseg = V_tcp_pmtud_blackhole_mss;
6798 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated);
6799 			} else {
6800 				/* Use the default MSS. */
6801 				tp->t_maxseg = V_tcp_mssdflt;
6802 				/*
6803 				 * Disable Path MTU Discovery when we switch
6804 				 * to minmss.
6805 				 */
6806 				tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
6807 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
6808 			}
6809 #endif
6810 		} else {
6811 			/*
6812 			 * If further retransmissions are still unsuccessful
6813 			 * with a lowered MTU, maybe this isn't a blackhole
6814 			 * and we restore the previous MSS and blackhole
6815 			 * detection flags. The limit '6' is determined by
6816 			 * giving each probe stage (1448, 1188, 524) 2
6817 			 * chances to recover.
6818 			 */
6819 			if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) &&
6820 			    (tp->t_rxtshift >= 6)) {
6821 				tp->t_flags2 |= TF2_PLPMTU_PMTUD;
6822 				tp->t_flags2 &= ~TF2_PLPMTU_BLACKHOLE;
6823 				tp->t_maxseg = tp->t_pmtud_saved_maxseg;
6824 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_failed);
6825 			}
6826 		}
6827 	}
6828 	/*
6829 	 * Disable RFC1323 and SACK if we haven't got any response to
6830 	 * our third SYN to work-around some broken terminal servers
6831 	 * (most of which have hopefully been retired) that have bad VJ
6832 	 * header compression code which trashes TCP segments containing
6833 	 * unknown-to-them TCP options.
6834 	 */
6835 	if (tcp_rexmit_drop_options && (tp->t_state == TCPS_SYN_SENT) &&
6836 	    (tp->t_rxtshift == 3))
6837 		tp->t_flags &= ~(TF_REQ_SCALE|TF_REQ_TSTMP|TF_SACK_PERMIT);
6838 	/*
6839 	 * If we backed off this far, our srtt estimate is probably bogus.
6840 	 * Clobber it so we'll take the next rtt measurement as our srtt;
6841 	 * move the current srtt into rttvar to keep the current retransmit
6842 	 * times until then.
6843 	 */
6844 	if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
6845 #ifdef INET6
6846 		if ((inp->inp_vflag & INP_IPV6) != 0)
6847 			in6_losing(inp);
6848 		else
6849 #endif
6850 			in_losing(inp);
6851 		tp->t_rttvar += tp->t_srtt;
6852 		tp->t_srtt = 0;
6853 	}
6854 	sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
6855 	tp->snd_recover = tp->snd_max;
6856 	tp->t_flags |= TF_ACKNOW;
6857 	tp->t_rtttime = 0;
6858 	rack_cong_signal(tp, CC_RTO, tp->snd_una, __LINE__);
6859 out:
6860 	return (retval);
6861 }
6862 
6863 static int
6864 rack_process_timers(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, uint8_t hpts_calling, uint8_t *doing_tlp)
6865 {
6866 	int32_t ret = 0;
6867 	int32_t timers = (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK);
6868 
6869 	if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
6870 	    (tp->t_flags & TF_GPUTINPROG)) {
6871 		/*
6872 		 * We have a goodput in progress
6873 		 * and we have entered a late state.
6874 		 * Do we have enough data in the sb
6875 		 * to handle the GPUT request?
6876 		 */
6877 		uint32_t bytes;
6878 
6879 		bytes = tp->gput_ack - tp->gput_seq;
6880 		if (SEQ_GT(tp->gput_seq, tp->snd_una))
6881 			bytes += tp->gput_seq - tp->snd_una;
6882 		if (bytes > sbavail(&tptosocket(tp)->so_snd)) {
6883 			/*
6884 			 * There are not enough bytes in the socket
6885 			 * buffer that have been sent to cover this
6886 			 * measurement. Cancel it.
6887 			 */
6888 			rack_log_pacing_delay_calc(rack, (tp->gput_ack - tp->gput_seq) /*flex2*/,
6889 						   rack->r_ctl.rc_gp_srtt /*flex1*/,
6890 						   tp->gput_seq,
6891 						   0, 0, 18, __LINE__, NULL, 0);
6892 			tp->t_flags &= ~TF_GPUTINPROG;
6893 		}
6894 	}
6895 	if (timers == 0) {
6896 		return (0);
6897 	}
6898 	if (tp->t_state == TCPS_LISTEN) {
6899 		/* no timers on listen sockets */
6900 		if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)
6901 			return (0);
6902 		return (1);
6903 	}
6904 	if ((timers & PACE_TMR_RACK) &&
6905 	    rack->rc_on_min_to) {
6906 		/*
6907 		 * For the rack timer when we
6908 		 * are on a min-timeout (which means rrr_conf = 3)
6909 		 * we don't want to check the timer. It may
6910 		 * be going off for a pace and thats ok we
6911 		 * want to send the retransmit (if its ready).
6912 		 *
6913 		 * If its on a normal rack timer (non-min) then
6914 		 * we will check if its expired.
6915 		 */
6916 		goto skip_time_check;
6917 	}
6918 	if (TSTMP_LT(cts, rack->r_ctl.rc_timer_exp)) {
6919 		uint32_t left;
6920 
6921 		if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
6922 			ret = -1;
6923 			rack_log_to_processing(rack, cts, ret, 0);
6924 			return (0);
6925 		}
6926 		if (hpts_calling == 0) {
6927 			/*
6928 			 * A user send or queued mbuf (sack) has called us? We
6929 			 * return 0 and let the pacing guards
6930 			 * deal with it if they should or
6931 			 * should not cause a send.
6932 			 */
6933 			ret = -2;
6934 			rack_log_to_processing(rack, cts, ret, 0);
6935 			return (0);
6936 		}
6937 		/*
6938 		 * Ok our timer went off early and we are not paced false
6939 		 * alarm, go back to sleep.
6940 		 */
6941 		ret = -3;
6942 		left = rack->r_ctl.rc_timer_exp - cts;
6943 		tcp_hpts_insert(tptoinpcb(tp), HPTS_MS_TO_SLOTS(left));
6944 		rack_log_to_processing(rack, cts, ret, left);
6945 		return (1);
6946 	}
6947 skip_time_check:
6948 	rack->rc_tmr_stopped = 0;
6949 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_MASK;
6950 	if (timers & PACE_TMR_DELACK) {
6951 		ret = rack_timeout_delack(tp, rack, cts);
6952 	} else if (timers & PACE_TMR_RACK) {
6953 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
6954 		rack->r_fast_output = 0;
6955 		ret = rack_timeout_rack(tp, rack, cts);
6956 	} else if (timers & PACE_TMR_TLP) {
6957 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
6958 		ret = rack_timeout_tlp(tp, rack, cts, doing_tlp);
6959 	} else if (timers & PACE_TMR_RXT) {
6960 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
6961 		rack->r_fast_output = 0;
6962 		ret = rack_timeout_rxt(tp, rack, cts);
6963 	} else if (timers & PACE_TMR_PERSIT) {
6964 		ret = rack_timeout_persist(tp, rack, cts);
6965 	} else if (timers & PACE_TMR_KEEP) {
6966 		ret = rack_timeout_keepalive(tp, rack, cts);
6967 	}
6968 	rack_log_to_processing(rack, cts, ret, timers);
6969 	return (ret);
6970 }
6971 
6972 static void
6973 rack_timer_cancel(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int line)
6974 {
6975 	struct timeval tv;
6976 	uint32_t us_cts, flags_on_entry;
6977 	uint8_t hpts_removed = 0;
6978 
6979 	flags_on_entry = rack->r_ctl.rc_hpts_flags;
6980 	us_cts = tcp_get_usecs(&tv);
6981 	if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
6982 	    ((TSTMP_GEQ(us_cts, rack->r_ctl.rc_last_output_to)) ||
6983 	     ((tp->snd_max - tp->snd_una) == 0))) {
6984 		tcp_hpts_remove(rack->rc_inp);
6985 		hpts_removed = 1;
6986 		/* If we were not delayed cancel out the flag. */
6987 		if ((tp->snd_max - tp->snd_una) == 0)
6988 			rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
6989 		rack_log_to_cancel(rack, hpts_removed, line, us_cts, &tv, flags_on_entry);
6990 	}
6991 	if (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) {
6992 		rack->rc_tmr_stopped = rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK;
6993 		if (tcp_in_hpts(rack->rc_inp) &&
6994 		    ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0)) {
6995 			/*
6996 			 * Canceling timer's when we have no output being
6997 			 * paced. We also must remove ourselves from the
6998 			 * hpts.
6999 			 */
7000 			tcp_hpts_remove(rack->rc_inp);
7001 			hpts_removed = 1;
7002 		}
7003 		rack->r_ctl.rc_hpts_flags &= ~(PACE_TMR_MASK);
7004 	}
7005 	if (hpts_removed == 0)
7006 		rack_log_to_cancel(rack, hpts_removed, line, us_cts, &tv, flags_on_entry);
7007 }
7008 
7009 static int
7010 rack_stopall(struct tcpcb *tp)
7011 {
7012 	struct tcp_rack *rack;
7013 	rack = (struct tcp_rack *)tp->t_fb_ptr;
7014 	rack->t_timers_stopped = 1;
7015 	return (0);
7016 }
7017 
7018 static void
7019 rack_stop_all_timers(struct tcpcb *tp)
7020 {
7021 	struct tcp_rack *rack;
7022 
7023 	/*
7024 	 * Assure no timers are running.
7025 	 */
7026 	if (tcp_timer_active(tp, TT_PERSIST)) {
7027 		/* We enter in persists, set the flag appropriately */
7028 		rack = (struct tcp_rack *)tp->t_fb_ptr;
7029 		rack->rc_in_persist = 1;
7030 	}
7031 }
7032 
7033 static void
7034 rack_update_rsm(struct tcpcb *tp, struct tcp_rack *rack,
7035     struct rack_sendmap *rsm, uint64_t ts, uint16_t add_flag)
7036 {
7037 	int32_t idx;
7038 
7039 	rsm->r_rtr_cnt++;
7040 	rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
7041 	rsm->r_dupack = 0;
7042 	if (rsm->r_rtr_cnt > RACK_NUM_OF_RETRANS) {
7043 		rsm->r_rtr_cnt = RACK_NUM_OF_RETRANS;
7044 		rsm->r_flags |= RACK_OVERMAX;
7045 	}
7046 	if ((rsm->r_rtr_cnt > 1) && ((rsm->r_flags & RACK_TLP) == 0)) {
7047 		rack->r_ctl.rc_holes_rxt += (rsm->r_end - rsm->r_start);
7048 		rsm->r_rtr_bytes += (rsm->r_end - rsm->r_start);
7049 	}
7050 	idx = rsm->r_rtr_cnt - 1;
7051 	rsm->r_tim_lastsent[idx] = ts;
7052 	/*
7053 	 * Here we don't add in the len of send, since its already
7054 	 * in snduna <->snd_max.
7055 	 */
7056 	rsm->r_fas = ctf_flight_size(rack->rc_tp,
7057 				     rack->r_ctl.rc_sacked);
7058 	if (rsm->r_flags & RACK_ACKED) {
7059 		/* Problably MTU discovery messing with us */
7060 		rsm->r_flags &= ~RACK_ACKED;
7061 		rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
7062 	}
7063 	if (rsm->r_in_tmap) {
7064 		TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7065 		rsm->r_in_tmap = 0;
7066 	}
7067 	TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7068 	rsm->r_in_tmap = 1;
7069 	/* Take off the must retransmit flag, if its on */
7070 	if (rsm->r_flags & RACK_MUST_RXT) {
7071 		if (rack->r_must_retran)
7072 			rack->r_ctl.rc_out_at_rto -= (rsm->r_end - rsm->r_start);
7073 		if (SEQ_GEQ(rsm->r_end, rack->r_ctl.rc_snd_max_at_rto)) {
7074 			/*
7075 			 * We have retransmitted all we need. Clear
7076 			 * any must retransmit flags.
7077 			 */
7078 			rack->r_must_retran = 0;
7079 			rack->r_ctl.rc_out_at_rto = 0;
7080 		}
7081 		rsm->r_flags &= ~RACK_MUST_RXT;
7082 	}
7083 	if (rsm->r_flags & RACK_SACK_PASSED) {
7084 		/* We have retransmitted due to the SACK pass */
7085 		rsm->r_flags &= ~RACK_SACK_PASSED;
7086 		rsm->r_flags |= RACK_WAS_SACKPASS;
7087 	}
7088 }
7089 
7090 static uint32_t
7091 rack_update_entry(struct tcpcb *tp, struct tcp_rack *rack,
7092     struct rack_sendmap *rsm, uint64_t ts, int32_t *lenp, uint16_t add_flag)
7093 {
7094 	/*
7095 	 * We (re-)transmitted starting at rsm->r_start for some length
7096 	 * (possibly less than r_end.
7097 	 */
7098 	struct rack_sendmap *nrsm;
7099 #ifdef INVARIANTS
7100 	struct rack_sendmap *insret;
7101 #endif
7102 	uint32_t c_end;
7103 	int32_t len;
7104 
7105 	len = *lenp;
7106 	c_end = rsm->r_start + len;
7107 	if (SEQ_GEQ(c_end, rsm->r_end)) {
7108 		/*
7109 		 * We retransmitted the whole piece or more than the whole
7110 		 * slopping into the next rsm.
7111 		 */
7112 		rack_update_rsm(tp, rack, rsm, ts, add_flag);
7113 		if (c_end == rsm->r_end) {
7114 			*lenp = 0;
7115 			return (0);
7116 		} else {
7117 			int32_t act_len;
7118 
7119 			/* Hangs over the end return whats left */
7120 			act_len = rsm->r_end - rsm->r_start;
7121 			*lenp = (len - act_len);
7122 			return (rsm->r_end);
7123 		}
7124 		/* We don't get out of this block. */
7125 	}
7126 	/*
7127 	 * Here we retransmitted less than the whole thing which means we
7128 	 * have to split this into what was transmitted and what was not.
7129 	 */
7130 	nrsm = rack_alloc_full_limit(rack);
7131 	if (nrsm == NULL) {
7132 		/*
7133 		 * We can't get memory, so lets not proceed.
7134 		 */
7135 		*lenp = 0;
7136 		return (0);
7137 	}
7138 	/*
7139 	 * So here we are going to take the original rsm and make it what we
7140 	 * retransmitted. nrsm will be the tail portion we did not
7141 	 * retransmit. For example say the chunk was 1, 11 (10 bytes). And
7142 	 * we retransmitted 5 bytes i.e. 1, 5. The original piece shrinks to
7143 	 * 1, 6 and the new piece will be 6, 11.
7144 	 */
7145 	rack_clone_rsm(rack, nrsm, rsm, c_end);
7146 	nrsm->r_dupack = 0;
7147 	rack_log_retran_reason(rack, nrsm, __LINE__, 0, 2);
7148 #ifndef INVARIANTS
7149 	(void)RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
7150 #else
7151 	insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
7152 	if (insret != NULL) {
7153 		panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
7154 		      nrsm, insret, rack, rsm);
7155 	}
7156 #endif
7157 	if (rsm->r_in_tmap) {
7158 		TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
7159 		nrsm->r_in_tmap = 1;
7160 	}
7161 	rsm->r_flags &= (~RACK_HAS_FIN);
7162 	rack_update_rsm(tp, rack, rsm, ts, add_flag);
7163 	/* Log a split of rsm into rsm and nrsm */
7164 	rack_log_map_chg(tp, rack, NULL, rsm, nrsm, MAP_SPLIT, 0, __LINE__);
7165 	*lenp = 0;
7166 	return (0);
7167 }
7168 
7169 static void
7170 rack_log_output(struct tcpcb *tp, struct tcpopt *to, int32_t len,
7171 		uint32_t seq_out, uint16_t th_flags, int32_t err, uint64_t cts,
7172 		struct rack_sendmap *hintrsm, uint16_t add_flag, struct mbuf *s_mb, uint32_t s_moff, int hw_tls)
7173 {
7174 	struct tcp_rack *rack;
7175 	struct rack_sendmap *rsm, *nrsm, fe;
7176 #ifdef INVARIANTS
7177 	struct rack_sendmap *insret;
7178 #endif
7179 	register uint32_t snd_max, snd_una;
7180 
7181 	/*
7182 	 * Add to the RACK log of packets in flight or retransmitted. If
7183 	 * there is a TS option we will use the TS echoed, if not we will
7184 	 * grab a TS.
7185 	 *
7186 	 * Retransmissions will increment the count and move the ts to its
7187 	 * proper place. Note that if options do not include TS's then we
7188 	 * won't be able to effectively use the ACK for an RTT on a retran.
7189 	 *
7190 	 * Notes about r_start and r_end. Lets consider a send starting at
7191 	 * sequence 1 for 10 bytes. In such an example the r_start would be
7192 	 * 1 (starting sequence) but the r_end would be r_start+len i.e. 11.
7193 	 * This means that r_end is actually the first sequence for the next
7194 	 * slot (11).
7195 	 *
7196 	 */
7197 	/*
7198 	 * If err is set what do we do XXXrrs? should we not add the thing?
7199 	 * -- i.e. return if err != 0 or should we pretend we sent it? --
7200 	 * i.e. proceed with add ** do this for now.
7201 	 */
7202 	INP_WLOCK_ASSERT(tptoinpcb(tp));
7203 	if (err)
7204 		/*
7205 		 * We don't log errors -- we could but snd_max does not
7206 		 * advance in this case either.
7207 		 */
7208 		return;
7209 
7210 	if (th_flags & TH_RST) {
7211 		/*
7212 		 * We don't log resets and we return immediately from
7213 		 * sending
7214 		 */
7215 		return;
7216 	}
7217 	rack = (struct tcp_rack *)tp->t_fb_ptr;
7218 	snd_una = tp->snd_una;
7219 	snd_max = tp->snd_max;
7220 	if (th_flags & (TH_SYN | TH_FIN)) {
7221 		/*
7222 		 * The call to rack_log_output is made before bumping
7223 		 * snd_max. This means we can record one extra byte on a SYN
7224 		 * or FIN if seq_out is adding more on and a FIN is present
7225 		 * (and we are not resending).
7226 		 */
7227 		if ((th_flags & TH_SYN) && (seq_out == tp->iss))
7228 			len++;
7229 		if (th_flags & TH_FIN)
7230 			len++;
7231 		if (SEQ_LT(snd_max, tp->snd_nxt)) {
7232 			/*
7233 			 * The add/update as not been done for the FIN/SYN
7234 			 * yet.
7235 			 */
7236 			snd_max = tp->snd_nxt;
7237 		}
7238 	}
7239 	if (SEQ_LEQ((seq_out + len), snd_una)) {
7240 		/* Are sending an old segment to induce an ack (keep-alive)? */
7241 		return;
7242 	}
7243 	if (SEQ_LT(seq_out, snd_una)) {
7244 		/* huh? should we panic? */
7245 		uint32_t end;
7246 
7247 		end = seq_out + len;
7248 		seq_out = snd_una;
7249 		if (SEQ_GEQ(end, seq_out))
7250 			len = end - seq_out;
7251 		else
7252 			len = 0;
7253 	}
7254 	if (len == 0) {
7255 		/* We don't log zero window probes */
7256 		return;
7257 	}
7258 	if (IN_FASTRECOVERY(tp->t_flags)) {
7259 		rack->r_ctl.rc_prr_out += len;
7260 	}
7261 	/* First question is it a retransmission or new? */
7262 	if (seq_out == snd_max) {
7263 		/* Its new */
7264 again:
7265 		rsm = rack_alloc(rack);
7266 		if (rsm == NULL) {
7267 			/*
7268 			 * Hmm out of memory and the tcb got destroyed while
7269 			 * we tried to wait.
7270 			 */
7271 			return;
7272 		}
7273 		if (th_flags & TH_FIN) {
7274 			rsm->r_flags = RACK_HAS_FIN|add_flag;
7275 		} else {
7276 			rsm->r_flags = add_flag;
7277 		}
7278 		if (hw_tls)
7279 			rsm->r_hw_tls = 1;
7280 		rsm->r_tim_lastsent[0] = cts;
7281 		rsm->r_rtr_cnt = 1;
7282 		rsm->r_rtr_bytes = 0;
7283 		if (th_flags & TH_SYN) {
7284 			/* The data space is one beyond snd_una */
7285 			rsm->r_flags |= RACK_HAS_SYN;
7286 		}
7287 		rsm->r_start = seq_out;
7288 		rsm->r_end = rsm->r_start + len;
7289 		rsm->r_dupack = 0;
7290 		/*
7291 		 * save off the mbuf location that
7292 		 * sndmbuf_noadv returned (which is
7293 		 * where we started copying from)..
7294 		 */
7295 		rsm->m = s_mb;
7296 		rsm->soff = s_moff;
7297 		/*
7298 		 * Here we do add in the len of send, since its not yet
7299 		 * reflected in in snduna <->snd_max
7300 		 */
7301 		rsm->r_fas = (ctf_flight_size(rack->rc_tp,
7302 					      rack->r_ctl.rc_sacked) +
7303 			      (rsm->r_end - rsm->r_start));
7304 		/* rsm->m will be NULL if RACK_HAS_SYN or RACK_HAS_FIN is set */
7305 		if (rsm->m) {
7306 			if (rsm->m->m_len <= rsm->soff) {
7307 				/*
7308 				 * XXXrrs Question, will this happen?
7309 				 *
7310 				 * If sbsndptr is set at the correct place
7311 				 * then s_moff should always be somewhere
7312 				 * within rsm->m. But if the sbsndptr was
7313 				 * off then that won't be true. If it occurs
7314 				 * we need to walkout to the correct location.
7315 				 */
7316 				struct mbuf *lm;
7317 
7318 				lm = rsm->m;
7319 				while (lm->m_len <= rsm->soff) {
7320 					rsm->soff -= lm->m_len;
7321 					lm = lm->m_next;
7322 					KASSERT(lm != NULL, ("%s rack:%p lm goes null orig_off:%u origmb:%p rsm->soff:%u",
7323 							     __func__, rack, s_moff, s_mb, rsm->soff));
7324 				}
7325 				rsm->m = lm;
7326 			}
7327 			rsm->orig_m_len = rsm->m->m_len;
7328 		} else
7329 			rsm->orig_m_len = 0;
7330 		rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
7331 		/* Log a new rsm */
7332 		rack_log_map_chg(tp, rack, NULL, rsm, NULL, MAP_NEW, 0, __LINE__);
7333 #ifndef INVARIANTS
7334 		(void)RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7335 #else
7336 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7337 		if (insret != NULL) {
7338 			panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
7339 			      nrsm, insret, rack, rsm);
7340 		}
7341 #endif
7342 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7343 		rsm->r_in_tmap = 1;
7344 		/*
7345 		 * Special case detection, is there just a single
7346 		 * packet outstanding when we are not in recovery?
7347 		 *
7348 		 * If this is true mark it so.
7349 		 */
7350 		if ((IN_FASTRECOVERY(tp->t_flags) == 0) &&
7351 		    (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) == ctf_fixed_maxseg(tp))) {
7352 			struct rack_sendmap *prsm;
7353 
7354 			prsm = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7355 			if (prsm)
7356 				prsm->r_one_out_nr = 1;
7357 		}
7358 		return;
7359 	}
7360 	/*
7361 	 * If we reach here its a retransmission and we need to find it.
7362 	 */
7363 	memset(&fe, 0, sizeof(fe));
7364 more:
7365 	if (hintrsm && (hintrsm->r_start == seq_out)) {
7366 		rsm = hintrsm;
7367 		hintrsm = NULL;
7368 	} else {
7369 		/* No hints sorry */
7370 		rsm = NULL;
7371 	}
7372 	if ((rsm) && (rsm->r_start == seq_out)) {
7373 		seq_out = rack_update_entry(tp, rack, rsm, cts, &len, add_flag);
7374 		if (len == 0) {
7375 			return;
7376 		} else {
7377 			goto more;
7378 		}
7379 	}
7380 	/* Ok it was not the last pointer go through it the hard way. */
7381 refind:
7382 	fe.r_start = seq_out;
7383 	rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
7384 	if (rsm) {
7385 		if (rsm->r_start == seq_out) {
7386 			seq_out = rack_update_entry(tp, rack, rsm, cts, &len, add_flag);
7387 			if (len == 0) {
7388 				return;
7389 			} else {
7390 				goto refind;
7391 			}
7392 		}
7393 		if (SEQ_GEQ(seq_out, rsm->r_start) && SEQ_LT(seq_out, rsm->r_end)) {
7394 			/* Transmitted within this piece */
7395 			/*
7396 			 * Ok we must split off the front and then let the
7397 			 * update do the rest
7398 			 */
7399 			nrsm = rack_alloc_full_limit(rack);
7400 			if (nrsm == NULL) {
7401 				rack_update_rsm(tp, rack, rsm, cts, add_flag);
7402 				return;
7403 			}
7404 			/*
7405 			 * copy rsm to nrsm and then trim the front of rsm
7406 			 * to not include this part.
7407 			 */
7408 			rack_clone_rsm(rack, nrsm, rsm, seq_out);
7409 			rack_log_map_chg(tp, rack, NULL, rsm, nrsm, MAP_SPLIT, 0, __LINE__);
7410 #ifndef INVARIANTS
7411 			(void)RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
7412 #else
7413 			insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
7414 			if (insret != NULL) {
7415 				panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
7416 				      nrsm, insret, rack, rsm);
7417 			}
7418 #endif
7419 			if (rsm->r_in_tmap) {
7420 				TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
7421 				nrsm->r_in_tmap = 1;
7422 			}
7423 			rsm->r_flags &= (~RACK_HAS_FIN);
7424 			seq_out = rack_update_entry(tp, rack, nrsm, cts, &len, add_flag);
7425 			if (len == 0) {
7426 				return;
7427 			} else if (len > 0)
7428 				goto refind;
7429 		}
7430 	}
7431 	/*
7432 	 * Hmm not found in map did they retransmit both old and on into the
7433 	 * new?
7434 	 */
7435 	if (seq_out == tp->snd_max) {
7436 		goto again;
7437 	} else if (SEQ_LT(seq_out, tp->snd_max)) {
7438 #ifdef INVARIANTS
7439 		printf("seq_out:%u len:%d snd_una:%u snd_max:%u -- but rsm not found?\n",
7440 		       seq_out, len, tp->snd_una, tp->snd_max);
7441 		printf("Starting Dump of all rack entries\n");
7442 		RB_FOREACH(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
7443 			printf("rsm:%p start:%u end:%u\n",
7444 			       rsm, rsm->r_start, rsm->r_end);
7445 		}
7446 		printf("Dump complete\n");
7447 		panic("seq_out not found rack:%p tp:%p",
7448 		      rack, tp);
7449 #endif
7450 	} else {
7451 #ifdef INVARIANTS
7452 		/*
7453 		 * Hmm beyond sndmax? (only if we are using the new rtt-pack
7454 		 * flag)
7455 		 */
7456 		panic("seq_out:%u(%d) is beyond snd_max:%u tp:%p",
7457 		      seq_out, len, tp->snd_max, tp);
7458 #endif
7459 	}
7460 }
7461 
7462 /*
7463  * Record one of the RTT updates from an ack into
7464  * our sample structure.
7465  */
7466 
7467 static void
7468 tcp_rack_xmit_timer(struct tcp_rack *rack, int32_t rtt, uint32_t len, uint32_t us_rtt,
7469 		    int confidence, struct rack_sendmap *rsm, uint16_t rtrcnt)
7470 {
7471 	if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) ||
7472 	    (rack->r_ctl.rack_rs.rs_rtt_lowest > rtt)) {
7473 		rack->r_ctl.rack_rs.rs_rtt_lowest = rtt;
7474 	}
7475 	if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) ||
7476 	    (rack->r_ctl.rack_rs.rs_rtt_highest < rtt)) {
7477 		rack->r_ctl.rack_rs.rs_rtt_highest = rtt;
7478 	}
7479 	if (rack->rc_tp->t_flags & TF_GPUTINPROG) {
7480 	    if (us_rtt < rack->r_ctl.rc_gp_lowrtt)
7481 		rack->r_ctl.rc_gp_lowrtt = us_rtt;
7482 	    if (rack->rc_tp->snd_wnd > rack->r_ctl.rc_gp_high_rwnd)
7483 		    rack->r_ctl.rc_gp_high_rwnd = rack->rc_tp->snd_wnd;
7484 	}
7485 	if ((confidence == 1) &&
7486 	    ((rsm == NULL) ||
7487 	     (rsm->r_just_ret) ||
7488 	     (rsm->r_one_out_nr &&
7489 	      len < (ctf_fixed_maxseg(rack->rc_tp) * 2)))) {
7490 		/*
7491 		 * If the rsm had a just return
7492 		 * hit it then we can't trust the
7493 		 * rtt measurement for buffer deterimination
7494 		 * Note that a confidence of 2, indicates
7495 		 * SACK'd which overrides the r_just_ret or
7496 		 * the r_one_out_nr. If it was a CUM-ACK and
7497 		 * we had only two outstanding, but get an
7498 		 * ack for only 1. Then that also lowers our
7499 		 * confidence.
7500 		 */
7501 		confidence = 0;
7502 	}
7503 	if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) ||
7504 	    (rack->r_ctl.rack_rs.rs_us_rtt > us_rtt)) {
7505 		if (rack->r_ctl.rack_rs.confidence == 0) {
7506 			/*
7507 			 * We take anything with no current confidence
7508 			 * saved.
7509 			 */
7510 			rack->r_ctl.rack_rs.rs_us_rtt = us_rtt;
7511 			rack->r_ctl.rack_rs.confidence = confidence;
7512 			rack->r_ctl.rack_rs.rs_us_rtrcnt = rtrcnt;
7513 		} else if (confidence || rack->r_ctl.rack_rs.confidence) {
7514 			/*
7515 			 * Once we have a confident number,
7516 			 * we can update it with a smaller
7517 			 * value since this confident number
7518 			 * may include the DSACK time until
7519 			 * the next segment (the second one) arrived.
7520 			 */
7521 			rack->r_ctl.rack_rs.rs_us_rtt = us_rtt;
7522 			rack->r_ctl.rack_rs.confidence = confidence;
7523 			rack->r_ctl.rack_rs.rs_us_rtrcnt = rtrcnt;
7524 		}
7525 	}
7526 	rack_log_rtt_upd(rack->rc_tp, rack, us_rtt, len, rsm, confidence);
7527 	rack->r_ctl.rack_rs.rs_flags = RACK_RTT_VALID;
7528 	rack->r_ctl.rack_rs.rs_rtt_tot += rtt;
7529 	rack->r_ctl.rack_rs.rs_rtt_cnt++;
7530 }
7531 
7532 /*
7533  * Collect new round-trip time estimate
7534  * and update averages and current timeout.
7535  */
7536 static void
7537 tcp_rack_xmit_timer_commit(struct tcp_rack *rack, struct tcpcb *tp)
7538 {
7539 	int32_t delta;
7540 	int32_t rtt;
7541 
7542 	if (rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY)
7543 		/* No valid sample */
7544 		return;
7545 	if (rack->r_ctl.rc_rate_sample_method == USE_RTT_LOW) {
7546 		/* We are to use the lowest RTT seen in a single ack */
7547 		rtt = rack->r_ctl.rack_rs.rs_rtt_lowest;
7548 	} else if (rack->r_ctl.rc_rate_sample_method == USE_RTT_HIGH) {
7549 		/* We are to use the highest RTT seen in a single ack */
7550 		rtt = rack->r_ctl.rack_rs.rs_rtt_highest;
7551 	} else if (rack->r_ctl.rc_rate_sample_method == USE_RTT_AVG) {
7552 		/* We are to use the average RTT seen in a single ack */
7553 		rtt = (int32_t)(rack->r_ctl.rack_rs.rs_rtt_tot /
7554 				(uint64_t)rack->r_ctl.rack_rs.rs_rtt_cnt);
7555 	} else {
7556 #ifdef INVARIANTS
7557 		panic("Unknown rtt variant %d", rack->r_ctl.rc_rate_sample_method);
7558 #endif
7559 		return;
7560 	}
7561 	if (rtt == 0)
7562 		rtt = 1;
7563 	if (rack->rc_gp_rtt_set == 0) {
7564 		/*
7565 		 * With no RTT we have to accept
7566 		 * even one we are not confident of.
7567 		 */
7568 		rack->r_ctl.rc_gp_srtt = rack->r_ctl.rack_rs.rs_us_rtt;
7569 		rack->rc_gp_rtt_set = 1;
7570 	} else if (rack->r_ctl.rack_rs.confidence) {
7571 		/* update the running gp srtt */
7572 		rack->r_ctl.rc_gp_srtt -= (rack->r_ctl.rc_gp_srtt/8);
7573 		rack->r_ctl.rc_gp_srtt += rack->r_ctl.rack_rs.rs_us_rtt / 8;
7574 	}
7575 	if (rack->r_ctl.rack_rs.confidence) {
7576 		/*
7577 		 * record the low and high for highly buffered path computation,
7578 		 * we only do this if we are confident (not a retransmission).
7579 		 */
7580 		if (rack->r_ctl.rc_highest_us_rtt < rack->r_ctl.rack_rs.rs_us_rtt) {
7581 			rack->r_ctl.rc_highest_us_rtt = rack->r_ctl.rack_rs.rs_us_rtt;
7582 		}
7583 		if (rack->rc_highly_buffered == 0) {
7584 			/*
7585 			 * Currently once we declare a path has
7586 			 * highly buffered there is no going
7587 			 * back, which may be a problem...
7588 			 */
7589 			if ((rack->r_ctl.rc_highest_us_rtt / rack->r_ctl.rc_lowest_us_rtt) > rack_hbp_thresh) {
7590 				rack_log_rtt_shrinks(rack, rack->r_ctl.rack_rs.rs_us_rtt,
7591 						     rack->r_ctl.rc_highest_us_rtt,
7592 						     rack->r_ctl.rc_lowest_us_rtt,
7593 						     RACK_RTTS_SEEHBP);
7594 				rack->rc_highly_buffered = 1;
7595 			}
7596 		}
7597 	}
7598 	if ((rack->r_ctl.rack_rs.confidence) ||
7599 	    (rack->r_ctl.rack_rs.rs_us_rtrcnt == 1)) {
7600 		/*
7601 		 * If we are highly confident of it <or> it was
7602 		 * never retransmitted we accept it as the last us_rtt.
7603 		 */
7604 		rack->r_ctl.rc_last_us_rtt = rack->r_ctl.rack_rs.rs_us_rtt;
7605 		/* The lowest rtt can be set if its was not retransmited */
7606 		if (rack->r_ctl.rc_lowest_us_rtt > rack->r_ctl.rack_rs.rs_us_rtt) {
7607 			rack->r_ctl.rc_lowest_us_rtt = rack->r_ctl.rack_rs.rs_us_rtt;
7608 			if (rack->r_ctl.rc_lowest_us_rtt == 0)
7609 				rack->r_ctl.rc_lowest_us_rtt = 1;
7610 		}
7611 	}
7612 	rack = (struct tcp_rack *)tp->t_fb_ptr;
7613 	if (tp->t_srtt != 0) {
7614 		/*
7615 		 * We keep a simple srtt in microseconds, like our rtt
7616 		 * measurement. We don't need to do any tricks with shifting
7617 		 * etc. Instead we just add in 1/8th of the new measurement
7618 		 * and subtract out 1/8 of the old srtt. We do the same with
7619 		 * the variance after finding the absolute value of the
7620 		 * difference between this sample and the current srtt.
7621 		 */
7622 		delta = tp->t_srtt - rtt;
7623 		/* Take off 1/8th of the current sRTT */
7624 		tp->t_srtt -= (tp->t_srtt >> 3);
7625 		/* Add in 1/8th of the new RTT just measured */
7626 		tp->t_srtt += (rtt >> 3);
7627 		if (tp->t_srtt <= 0)
7628 			tp->t_srtt = 1;
7629 		/* Now lets make the absolute value of the variance */
7630 		if (delta < 0)
7631 			delta = -delta;
7632 		/* Subtract out 1/8th */
7633 		tp->t_rttvar -= (tp->t_rttvar >> 3);
7634 		/* Add in 1/8th of the new variance we just saw */
7635 		tp->t_rttvar += (delta >> 3);
7636 		if (tp->t_rttvar <= 0)
7637 			tp->t_rttvar = 1;
7638 	} else {
7639 		/*
7640 		 * No rtt measurement yet - use the unsmoothed rtt. Set the
7641 		 * variance to half the rtt (so our first retransmit happens
7642 		 * at 3*rtt).
7643 		 */
7644 		tp->t_srtt = rtt;
7645 		tp->t_rttvar = rtt >> 1;
7646 	}
7647 	rack->rc_srtt_measure_made = 1;
7648 	KMOD_TCPSTAT_INC(tcps_rttupdated);
7649 	if (tp->t_rttupdated < UCHAR_MAX)
7650 		tp->t_rttupdated++;
7651 #ifdef STATS
7652 	if (rack_stats_gets_ms_rtt == 0) {
7653 		/* Send in the microsecond rtt used for rxt timeout purposes */
7654 		stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, rtt));
7655 	} else if (rack_stats_gets_ms_rtt == 1) {
7656 		/* Send in the millisecond rtt used for rxt timeout purposes */
7657 		int32_t ms_rtt;
7658 
7659 		/* Round up */
7660 		ms_rtt = (rtt + HPTS_USEC_IN_MSEC - 1) / HPTS_USEC_IN_MSEC;
7661 		stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, ms_rtt));
7662 	} else if (rack_stats_gets_ms_rtt == 2) {
7663 		/* Send in the millisecond rtt has close to the path RTT as we can get  */
7664 		int32_t ms_rtt;
7665 
7666 		/* Round up */
7667 		ms_rtt = (rack->r_ctl.rack_rs.rs_us_rtt + HPTS_USEC_IN_MSEC - 1) / HPTS_USEC_IN_MSEC;
7668 		stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, ms_rtt));
7669 	}  else {
7670 		/* Send in the microsecond rtt has close to the path RTT as we can get  */
7671 		stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, rack->r_ctl.rack_rs.rs_us_rtt));
7672 	}
7673 
7674 #endif
7675 	/*
7676 	 * the retransmit should happen at rtt + 4 * rttvar. Because of the
7677 	 * way we do the smoothing, srtt and rttvar will each average +1/2
7678 	 * tick of bias.  When we compute the retransmit timer, we want 1/2
7679 	 * tick of rounding and 1 extra tick because of +-1/2 tick
7680 	 * uncertainty in the firing of the timer.  The bias will give us
7681 	 * exactly the 1.5 tick we need.  But, because the bias is
7682 	 * statistical, we have to test that we don't drop below the minimum
7683 	 * feasible timer (which is 2 ticks).
7684 	 */
7685 	tp->t_rxtshift = 0;
7686 	RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
7687 		      max(rack_rto_min, rtt + 2), rack_rto_max, rack->r_ctl.timer_slop);
7688 	rack_log_rtt_sample(rack, rtt);
7689 	tp->t_softerror = 0;
7690 }
7691 
7692 
7693 static void
7694 rack_apply_updated_usrtt(struct tcp_rack *rack, uint32_t us_rtt, uint32_t us_cts)
7695 {
7696 	/*
7697 	 * Apply to filter the inbound us-rtt at us_cts.
7698 	 */
7699 	uint32_t old_rtt;
7700 
7701 	old_rtt = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
7702 	apply_filter_min_small(&rack->r_ctl.rc_gp_min_rtt,
7703 			       us_rtt, us_cts);
7704 	if (old_rtt > us_rtt) {
7705 		/* We just hit a new lower rtt time */
7706 		rack_log_rtt_shrinks(rack,  us_cts,  old_rtt,
7707 				     __LINE__, RACK_RTTS_NEWRTT);
7708 		/*
7709 		 * Only count it if its lower than what we saw within our
7710 		 * calculated range.
7711 		 */
7712 		if ((old_rtt - us_rtt) > rack_min_rtt_movement) {
7713 			if (rack_probertt_lower_within &&
7714 			    rack->rc_gp_dyn_mul &&
7715 			    (rack->use_fixed_rate == 0) &&
7716 			    (rack->rc_always_pace)) {
7717 				/*
7718 				 * We are seeing a new lower rtt very close
7719 				 * to the time that we would have entered probe-rtt.
7720 				 * This is probably due to the fact that a peer flow
7721 				 * has entered probe-rtt. Lets go in now too.
7722 				 */
7723 				uint32_t val;
7724 
7725 				val = rack_probertt_lower_within * rack_time_between_probertt;
7726 				val /= 100;
7727 				if ((rack->in_probe_rtt == 0)  &&
7728 				    ((us_cts - rack->r_ctl.rc_lower_rtt_us_cts) >= (rack_time_between_probertt - val)))	{
7729 					rack_enter_probertt(rack, us_cts);
7730 				}
7731 			}
7732 			rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
7733 		}
7734 	}
7735 }
7736 
7737 static int
7738 rack_update_rtt(struct tcpcb *tp, struct tcp_rack *rack,
7739     struct rack_sendmap *rsm, struct tcpopt *to, uint32_t cts, int32_t ack_type, tcp_seq th_ack)
7740 {
7741 	uint32_t us_rtt;
7742 	int32_t i, all;
7743 	uint32_t t, len_acked;
7744 
7745 	if ((rsm->r_flags & RACK_ACKED) ||
7746 	    (rsm->r_flags & RACK_WAS_ACKED))
7747 		/* Already done */
7748 		return (0);
7749 	if (rsm->r_no_rtt_allowed) {
7750 		/* Not allowed */
7751 		return (0);
7752 	}
7753 	if (ack_type == CUM_ACKED) {
7754 		if (SEQ_GT(th_ack, rsm->r_end)) {
7755 			len_acked = rsm->r_end - rsm->r_start;
7756 			all = 1;
7757 		} else {
7758 			len_acked = th_ack - rsm->r_start;
7759 			all = 0;
7760 		}
7761 	} else {
7762 		len_acked = rsm->r_end - rsm->r_start;
7763 		all = 0;
7764 	}
7765 	if (rsm->r_rtr_cnt == 1) {
7766 
7767 		t = cts - (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
7768 		if ((int)t <= 0)
7769 			t = 1;
7770 		if (!tp->t_rttlow || tp->t_rttlow > t)
7771 			tp->t_rttlow = t;
7772 		if (!rack->r_ctl.rc_rack_min_rtt ||
7773 		    SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
7774 			rack->r_ctl.rc_rack_min_rtt = t;
7775 			if (rack->r_ctl.rc_rack_min_rtt == 0) {
7776 				rack->r_ctl.rc_rack_min_rtt = 1;
7777 			}
7778 		}
7779 		if (TSTMP_GT(tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time), rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)]))
7780 			us_rtt = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time) - (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
7781 		else
7782 			us_rtt = tcp_get_usecs(NULL) - (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
7783 		if (us_rtt == 0)
7784 			us_rtt = 1;
7785 		if (CC_ALGO(tp)->rttsample != NULL) {
7786 			/* Kick the RTT to the CC */
7787 			CC_ALGO(tp)->rttsample(&tp->t_ccv, us_rtt, 1, rsm->r_fas);
7788 		}
7789 		rack_apply_updated_usrtt(rack, us_rtt, tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time));
7790 		if (ack_type == SACKED) {
7791 			rack_log_rtt_sample_calc(rack, t, (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)], cts, 1);
7792 			tcp_rack_xmit_timer(rack, t + 1, len_acked, us_rtt, 2 , rsm, rsm->r_rtr_cnt);
7793 		} else {
7794 			/*
7795 			 * We need to setup what our confidence
7796 			 * is in this ack.
7797 			 *
7798 			 * If the rsm was app limited and it is
7799 			 * less than a mss in length (the end
7800 			 * of the send) then we have a gap. If we
7801 			 * were app limited but say we were sending
7802 			 * multiple MSS's then we are more confident
7803 			 * int it.
7804 			 *
7805 			 * When we are not app-limited then we see if
7806 			 * the rsm is being included in the current
7807 			 * measurement, we tell this by the app_limited_needs_set
7808 			 * flag.
7809 			 *
7810 			 * Note that being cwnd blocked is not applimited
7811 			 * as well as the pacing delay between packets which
7812 			 * are sending only 1 or 2 MSS's also will show up
7813 			 * in the RTT. We probably need to examine this algorithm
7814 			 * a bit more and enhance it to account for the delay
7815 			 * between rsm's. We could do that by saving off the
7816 			 * pacing delay of each rsm (in an rsm) and then
7817 			 * factoring that in somehow though for now I am
7818 			 * not sure how :)
7819 			 */
7820 			int calc_conf = 0;
7821 
7822 			if (rsm->r_flags & RACK_APP_LIMITED) {
7823 				if (all && (len_acked <= ctf_fixed_maxseg(tp)))
7824 					calc_conf = 0;
7825 				else
7826 					calc_conf = 1;
7827 			} else if (rack->app_limited_needs_set == 0) {
7828 				calc_conf = 1;
7829 			} else {
7830 				calc_conf = 0;
7831 			}
7832 			rack_log_rtt_sample_calc(rack, t, (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)], cts, 2);
7833 			tcp_rack_xmit_timer(rack, t + 1, len_acked, us_rtt,
7834 					    calc_conf, rsm, rsm->r_rtr_cnt);
7835 		}
7836 		if ((rsm->r_flags & RACK_TLP) &&
7837 		    (!IN_FASTRECOVERY(tp->t_flags))) {
7838 			/* Segment was a TLP and our retrans matched */
7839 			if (rack->r_ctl.rc_tlp_cwnd_reduce) {
7840 				rack_cong_signal(tp, CC_NDUPACK, tp->snd_una, __LINE__);
7841 			}
7842 		}
7843 		if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time, (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)])) {
7844 			/* New more recent rack_tmit_time */
7845 			rack->r_ctl.rc_rack_tmit_time = (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
7846 			rack->rc_rack_rtt = t;
7847 		}
7848 		return (1);
7849 	}
7850 	/*
7851 	 * We clear the soft/rxtshift since we got an ack.
7852 	 * There is no assurance we will call the commit() function
7853 	 * so we need to clear these to avoid incorrect handling.
7854 	 */
7855 	tp->t_rxtshift = 0;
7856 	RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
7857 		      rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
7858 	tp->t_softerror = 0;
7859 	if (to && (to->to_flags & TOF_TS) &&
7860 	    (ack_type == CUM_ACKED) &&
7861 	    (to->to_tsecr) &&
7862 	    ((rsm->r_flags & RACK_OVERMAX) == 0)) {
7863 		/*
7864 		 * Now which timestamp does it match? In this block the ACK
7865 		 * must be coming from a previous transmission.
7866 		 */
7867 		for (i = 0; i < rsm->r_rtr_cnt; i++) {
7868 			if (rack_ts_to_msec(rsm->r_tim_lastsent[i]) == to->to_tsecr) {
7869 				t = cts - (uint32_t)rsm->r_tim_lastsent[i];
7870 				if ((int)t <= 0)
7871 					t = 1;
7872 				if (CC_ALGO(tp)->rttsample != NULL) {
7873 					/*
7874 					 * Kick the RTT to the CC, here
7875 					 * we lie a bit in that we know the
7876 					 * retransmission is correct even though
7877 					 * we retransmitted. This is because
7878 					 * we match the timestamps.
7879 					 */
7880 					if (TSTMP_GT(tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time), rsm->r_tim_lastsent[i]))
7881 						us_rtt = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time) - (uint32_t)rsm->r_tim_lastsent[i];
7882 					else
7883 						us_rtt = tcp_get_usecs(NULL) - (uint32_t)rsm->r_tim_lastsent[i];
7884 					CC_ALGO(tp)->rttsample(&tp->t_ccv, us_rtt, 1, rsm->r_fas);
7885 				}
7886 				if ((i + 1) < rsm->r_rtr_cnt) {
7887 					/*
7888 					 * The peer ack'd from our previous
7889 					 * transmission. We have a spurious
7890 					 * retransmission and thus we dont
7891 					 * want to update our rack_rtt.
7892 					 *
7893 					 * Hmm should there be a CC revert here?
7894 					 *
7895 					 */
7896 					return (0);
7897 				}
7898 				if (!tp->t_rttlow || tp->t_rttlow > t)
7899 					tp->t_rttlow = t;
7900 				if (!rack->r_ctl.rc_rack_min_rtt || SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
7901 					rack->r_ctl.rc_rack_min_rtt = t;
7902 					if (rack->r_ctl.rc_rack_min_rtt == 0) {
7903 						rack->r_ctl.rc_rack_min_rtt = 1;
7904 					}
7905 				}
7906 				if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time,
7907 					   (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)])) {
7908 					/* New more recent rack_tmit_time */
7909 					rack->r_ctl.rc_rack_tmit_time = (uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
7910 					rack->rc_rack_rtt = t;
7911 				}
7912 				rack_log_rtt_sample_calc(rack, t, (uint32_t)rsm->r_tim_lastsent[i], cts, 3);
7913 				tcp_rack_xmit_timer(rack, t + 1, len_acked, t, 0, rsm,
7914 						    rsm->r_rtr_cnt);
7915 				return (1);
7916 			}
7917 		}
7918 		goto ts_not_found;
7919 	} else {
7920 		/*
7921 		 * Ok its a SACK block that we retransmitted. or a windows
7922 		 * machine without timestamps. We can tell nothing from the
7923 		 * time-stamp since its not there or the time the peer last
7924 		 * recieved a segment that moved forward its cum-ack point.
7925 		 */
7926 ts_not_found:
7927 		i = rsm->r_rtr_cnt - 1;
7928 		t = cts - (uint32_t)rsm->r_tim_lastsent[i];
7929 		if ((int)t <= 0)
7930 			t = 1;
7931 		if (rack->r_ctl.rc_rack_min_rtt && SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
7932 			/*
7933 			 * We retransmitted and the ack came back in less
7934 			 * than the smallest rtt we have observed. We most
7935 			 * likely did an improper retransmit as outlined in
7936 			 * 6.2 Step 2 point 2 in the rack-draft so we
7937 			 * don't want to update our rack_rtt. We in
7938 			 * theory (in future) might want to think about reverting our
7939 			 * cwnd state but we won't for now.
7940 			 */
7941 			return (0);
7942 		} else if (rack->r_ctl.rc_rack_min_rtt) {
7943 			/*
7944 			 * We retransmitted it and the retransmit did the
7945 			 * job.
7946 			 */
7947 			if (!rack->r_ctl.rc_rack_min_rtt ||
7948 			    SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
7949 				rack->r_ctl.rc_rack_min_rtt = t;
7950 				if (rack->r_ctl.rc_rack_min_rtt == 0) {
7951 					rack->r_ctl.rc_rack_min_rtt = 1;
7952 				}
7953 			}
7954 			if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time, (uint32_t)rsm->r_tim_lastsent[i])) {
7955 				/* New more recent rack_tmit_time */
7956 				rack->r_ctl.rc_rack_tmit_time = (uint32_t)rsm->r_tim_lastsent[i];
7957 				rack->rc_rack_rtt = t;
7958 			}
7959 			return (1);
7960 		}
7961 	}
7962 	return (0);
7963 }
7964 
7965 /*
7966  * Mark the SACK_PASSED flag on all entries prior to rsm send wise.
7967  */
7968 static void
7969 rack_log_sack_passed(struct tcpcb *tp,
7970     struct tcp_rack *rack, struct rack_sendmap *rsm)
7971 {
7972 	struct rack_sendmap *nrsm;
7973 
7974 	nrsm = rsm;
7975 	TAILQ_FOREACH_REVERSE_FROM(nrsm, &rack->r_ctl.rc_tmap,
7976 	    rack_head, r_tnext) {
7977 		if (nrsm == rsm) {
7978 			/* Skip original segment he is acked */
7979 			continue;
7980 		}
7981 		if (nrsm->r_flags & RACK_ACKED) {
7982 			/*
7983 			 * Skip ack'd segments, though we
7984 			 * should not see these, since tmap
7985 			 * should not have ack'd segments.
7986 			 */
7987 			continue;
7988 		}
7989 		if (nrsm->r_flags & RACK_RWND_COLLAPSED) {
7990 			/*
7991 			 * If the peer dropped the rwnd on
7992 			 * these then we don't worry about them.
7993 			 */
7994 			continue;
7995 		}
7996 		if (nrsm->r_flags & RACK_SACK_PASSED) {
7997 			/*
7998 			 * We found one that is already marked
7999 			 * passed, we have been here before and
8000 			 * so all others below this are marked.
8001 			 */
8002 			break;
8003 		}
8004 		nrsm->r_flags |= RACK_SACK_PASSED;
8005 		nrsm->r_flags &= ~RACK_WAS_SACKPASS;
8006 	}
8007 }
8008 
8009 static void
8010 rack_need_set_test(struct tcpcb *tp,
8011 		   struct tcp_rack *rack,
8012 		   struct rack_sendmap *rsm,
8013 		   tcp_seq th_ack,
8014 		   int line,
8015 		   int use_which)
8016 {
8017 
8018 	if ((tp->t_flags & TF_GPUTINPROG) &&
8019 	    SEQ_GEQ(rsm->r_end, tp->gput_seq)) {
8020 		/*
8021 		 * We were app limited, and this ack
8022 		 * butts up or goes beyond the point where we want
8023 		 * to start our next measurement. We need
8024 		 * to record the new gput_ts as here and
8025 		 * possibly update the start sequence.
8026 		 */
8027 		uint32_t seq, ts;
8028 
8029 		if (rsm->r_rtr_cnt > 1) {
8030 			/*
8031 			 * This is a retransmit, can we
8032 			 * really make any assessment at this
8033 			 * point?  We are not really sure of
8034 			 * the timestamp, is it this or the
8035 			 * previous transmission?
8036 			 *
8037 			 * Lets wait for something better that
8038 			 * is not retransmitted.
8039 			 */
8040 			return;
8041 		}
8042 		seq = tp->gput_seq;
8043 		ts = tp->gput_ts;
8044 		rack->app_limited_needs_set = 0;
8045 		tp->gput_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
8046 		/* Do we start at a new end? */
8047 		if ((use_which == RACK_USE_BEG) &&
8048 		    SEQ_GEQ(rsm->r_start, tp->gput_seq)) {
8049 			/*
8050 			 * When we get an ACK that just eats
8051 			 * up some of the rsm, we set RACK_USE_BEG
8052 			 * since whats at r_start (i.e. th_ack)
8053 			 * is left unacked and thats where the
8054 			 * measurement not starts.
8055 			 */
8056 			tp->gput_seq = rsm->r_start;
8057 			rack->r_ctl.rc_gp_output_ts = rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
8058 		}
8059 		if ((use_which == RACK_USE_END) &&
8060 		    SEQ_GEQ(rsm->r_end, tp->gput_seq)) {
8061 			    /*
8062 			     * We use the end when the cumack
8063 			     * is moving forward and completely
8064 			     * deleting the rsm passed so basically
8065 			     * r_end holds th_ack.
8066 			     *
8067 			     * For SACK's we also want to use the end
8068 			     * since this piece just got sacked and
8069 			     * we want to target anything after that
8070 			     * in our measurement.
8071 			     */
8072 			    tp->gput_seq = rsm->r_end;
8073 			    rack->r_ctl.rc_gp_output_ts = rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
8074 		}
8075 		if (use_which == RACK_USE_END_OR_THACK) {
8076 			/*
8077 			 * special case for ack moving forward,
8078 			 * not a sack, we need to move all the
8079 			 * way up to where this ack cum-ack moves
8080 			 * to.
8081 			 */
8082 			if (SEQ_GT(th_ack, rsm->r_end))
8083 				tp->gput_seq = th_ack;
8084 			else
8085 				tp->gput_seq = rsm->r_end;
8086 			rack->r_ctl.rc_gp_output_ts = rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
8087 		}
8088 		if (SEQ_GT(tp->gput_seq, tp->gput_ack)) {
8089 			/*
8090 			 * We moved beyond this guy's range, re-calculate
8091 			 * the new end point.
8092 			 */
8093 			if (rack->rc_gp_filled == 0) {
8094 				tp->gput_ack = tp->gput_seq + max(rc_init_window(rack), (MIN_GP_WIN * ctf_fixed_maxseg(tp)));
8095 			} else {
8096 				tp->gput_ack = tp->gput_seq + rack_get_measure_window(tp, rack);
8097 			}
8098 		}
8099 		/*
8100 		 * We are moving the goal post, we may be able to clear the
8101 		 * measure_saw_probe_rtt flag.
8102 		 */
8103 		if ((rack->in_probe_rtt == 0) &&
8104 		    (rack->measure_saw_probe_rtt) &&
8105 		    (SEQ_GEQ(tp->gput_seq, rack->r_ctl.rc_probertt_sndmax_atexit)))
8106 			rack->measure_saw_probe_rtt = 0;
8107 		rack_log_pacing_delay_calc(rack, ts, tp->gput_ts,
8108 					   seq, tp->gput_seq, 0, 5, line, NULL, 0);
8109 		if (rack->rc_gp_filled &&
8110 		    ((tp->gput_ack - tp->gput_seq) <
8111 		     max(rc_init_window(rack), (MIN_GP_WIN *
8112 						ctf_fixed_maxseg(tp))))) {
8113 			uint32_t ideal_amount;
8114 
8115 			ideal_amount = rack_get_measure_window(tp, rack);
8116 			if (ideal_amount > sbavail(&tptosocket(tp)->so_snd)) {
8117 				/*
8118 				 * There is no sense of continuing this measurement
8119 				 * because its too small to gain us anything we
8120 				 * trust. Skip it and that way we can start a new
8121 				 * measurement quicker.
8122 				 */
8123 				tp->t_flags &= ~TF_GPUTINPROG;
8124 				rack_log_pacing_delay_calc(rack, tp->gput_ack, tp->gput_seq,
8125 							   0, 0, 0, 6, __LINE__, NULL, 0);
8126 			} else {
8127 				/*
8128 				 * Reset the window further out.
8129 				 */
8130 				tp->gput_ack = tp->gput_seq + ideal_amount;
8131 			}
8132 		}
8133 	}
8134 }
8135 
8136 static inline int
8137 is_rsm_inside_declared_tlp_block(struct tcp_rack *rack, struct rack_sendmap *rsm)
8138 {
8139 	if (SEQ_LT(rsm->r_end, rack->r_ctl.last_tlp_acked_start)) {
8140 		/* Behind our TLP definition or right at */
8141 		return (0);
8142 	}
8143 	if (SEQ_GT(rsm->r_start, rack->r_ctl.last_tlp_acked_end)) {
8144 		/* The start is beyond or right at our end of TLP definition */
8145 		return (0);
8146 	}
8147 	/* It has to be a sub-part of the original TLP recorded */
8148 	return (1);
8149 }
8150 
8151 
8152 static uint32_t
8153 rack_proc_sack_blk(struct tcpcb *tp, struct tcp_rack *rack, struct sackblk *sack,
8154 		   struct tcpopt *to, struct rack_sendmap **prsm, uint32_t cts, int *moved_two)
8155 {
8156 	uint32_t start, end, changed = 0;
8157 	struct rack_sendmap stack_map;
8158 	struct rack_sendmap *rsm, *nrsm, fe, *prev, *next;
8159 #ifdef INVARIANTS
8160 	struct rack_sendmap *insret;
8161 #endif
8162 	int32_t used_ref = 1;
8163 	int moved = 0;
8164 
8165 	start = sack->start;
8166 	end = sack->end;
8167 	rsm = *prsm;
8168 	memset(&fe, 0, sizeof(fe));
8169 do_rest_ofb:
8170 	if ((rsm == NULL) ||
8171 	    (SEQ_LT(end, rsm->r_start)) ||
8172 	    (SEQ_GEQ(start, rsm->r_end)) ||
8173 	    (SEQ_LT(start, rsm->r_start))) {
8174 		/*
8175 		 * We are not in the right spot,
8176 		 * find the correct spot in the tree.
8177 		 */
8178 		used_ref = 0;
8179 		fe.r_start = start;
8180 		rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
8181 		moved++;
8182 	}
8183 	if (rsm == NULL) {
8184 		/* TSNH */
8185 		goto out;
8186 	}
8187 	/* Ok we have an ACK for some piece of this rsm */
8188 	if (rsm->r_start != start) {
8189 		if ((rsm->r_flags & RACK_ACKED) == 0) {
8190 			/*
8191 			 * Before any splitting or hookery is
8192 			 * done is it a TLP of interest i.e. rxt?
8193 			 */
8194 			if ((rsm->r_flags & RACK_TLP) &&
8195 			    (rsm->r_rtr_cnt > 1)) {
8196 				/*
8197 				 * We are splitting a rxt TLP, check
8198 				 * if we need to save off the start/end
8199 				 */
8200 				if (rack->rc_last_tlp_acked_set &&
8201 				    (is_rsm_inside_declared_tlp_block(rack, rsm))) {
8202 					/*
8203 					 * We already turned this on since we are inside
8204 					 * the previous one was a partially sack now we
8205 					 * are getting another one (maybe all of it).
8206 					 *
8207 					 */
8208 					rack_log_dsack_event(rack, 10, __LINE__, rsm->r_start, rsm->r_end);
8209 					/*
8210 					 * Lets make sure we have all of it though.
8211 					 */
8212 					if (SEQ_LT(rsm->r_start, rack->r_ctl.last_tlp_acked_start)) {
8213 						rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8214 						rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8215 								     rack->r_ctl.last_tlp_acked_end);
8216 					}
8217 					if (SEQ_GT(rsm->r_end, rack->r_ctl.last_tlp_acked_end)) {
8218 						rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8219 						rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8220 								     rack->r_ctl.last_tlp_acked_end);
8221 					}
8222 				} else {
8223 					rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8224 					rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8225 					rack->rc_last_tlp_past_cumack = 0;
8226 					rack->rc_last_tlp_acked_set = 1;
8227 					rack_log_dsack_event(rack, 8, __LINE__, rsm->r_start, rsm->r_end);
8228 				}
8229 			}
8230 			/**
8231 			 * Need to split this in two pieces the before and after,
8232 			 * the before remains in the map, the after must be
8233 			 * added. In other words we have:
8234 			 * rsm        |--------------|
8235 			 * sackblk        |------->
8236 			 * rsm will become
8237 			 *     rsm    |---|
8238 			 * and nrsm will be  the sacked piece
8239 			 *     nrsm       |----------|
8240 			 *
8241 			 * But before we start down that path lets
8242 			 * see if the sack spans over on top of
8243 			 * the next guy and it is already sacked.
8244 			 *
8245 			 */
8246 			next = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8247 			if (next && (next->r_flags & RACK_ACKED) &&
8248 			    SEQ_GEQ(end, next->r_start)) {
8249 				/**
8250 				 * So the next one is already acked, and
8251 				 * we can thus by hookery use our stack_map
8252 				 * to reflect the piece being sacked and
8253 				 * then adjust the two tree entries moving
8254 				 * the start and ends around. So we start like:
8255 				 *  rsm     |------------|             (not-acked)
8256 				 *  next                 |-----------| (acked)
8257 				 *  sackblk        |-------->
8258 				 *  We want to end like so:
8259 				 *  rsm     |------|                   (not-acked)
8260 				 *  next           |-----------------| (acked)
8261 				 *  nrsm           |-----|
8262 				 * Where nrsm is a temporary stack piece we
8263 				 * use to update all the gizmos.
8264 				 */
8265 				/* Copy up our fudge block */
8266 				nrsm = &stack_map;
8267 				memcpy(nrsm, rsm, sizeof(struct rack_sendmap));
8268 				/* Now adjust our tree blocks */
8269 				rsm->r_end = start;
8270 				next->r_start = start;
8271 				/* Now we must adjust back where next->m is */
8272 				rack_setup_offset_for_rsm(rsm, next);
8273 
8274 				/* We don't need to adjust rsm, it did not change */
8275 				/* Clear out the dup ack count of the remainder */
8276 				rsm->r_dupack = 0;
8277 				rsm->r_just_ret = 0;
8278 				rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
8279 				/* Now lets make sure our fudge block is right */
8280 				nrsm->r_start = start;
8281 				/* Now lets update all the stats and such */
8282 				rack_update_rtt(tp, rack, nrsm, to, cts, SACKED, 0);
8283 				if (rack->app_limited_needs_set)
8284 					rack_need_set_test(tp, rack, nrsm, tp->snd_una, __LINE__, RACK_USE_END);
8285 				changed += (nrsm->r_end - nrsm->r_start);
8286 				rack->r_ctl.rc_sacked += (nrsm->r_end - nrsm->r_start);
8287 				if (nrsm->r_flags & RACK_SACK_PASSED) {
8288 					rack->r_ctl.rc_reorder_ts = cts;
8289 				}
8290 				/*
8291 				 * Now we want to go up from rsm (the
8292 				 * one left un-acked) to the next one
8293 				 * in the tmap. We do this so when
8294 				 * we walk backwards we include marking
8295 				 * sack-passed on rsm (The one passed in
8296 				 * is skipped since it is generally called
8297 				 * on something sacked before removing it
8298 				 * from the tmap).
8299 				 */
8300 				if (rsm->r_in_tmap) {
8301 					nrsm = TAILQ_NEXT(rsm, r_tnext);
8302 					/*
8303 					 * Now that we have the next
8304 					 * one walk backwards from there.
8305 					 */
8306 					if (nrsm && nrsm->r_in_tmap)
8307 						rack_log_sack_passed(tp, rack, nrsm);
8308 				}
8309 				/* Now are we done? */
8310 				if (SEQ_LT(end, next->r_end) ||
8311 				    (end == next->r_end)) {
8312 					/* Done with block */
8313 					goto out;
8314 				}
8315 				rack_log_map_chg(tp, rack, &stack_map, rsm, next, MAP_SACK_M1, end, __LINE__);
8316 				counter_u64_add(rack_sack_used_next_merge, 1);
8317 				/* Postion for the next block */
8318 				start = next->r_end;
8319 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, next);
8320 				if (rsm == NULL)
8321 					goto out;
8322 			} else {
8323 				/**
8324 				 * We can't use any hookery here, so we
8325 				 * need to split the map. We enter like
8326 				 * so:
8327 				 *  rsm      |--------|
8328 				 *  sackblk       |----->
8329 				 * We will add the new block nrsm and
8330 				 * that will be the new portion, and then
8331 				 * fall through after reseting rsm. So we
8332 				 * split and look like this:
8333 				 *  rsm      |----|
8334 				 *  sackblk       |----->
8335 				 *  nrsm          |---|
8336 				 * We then fall through reseting
8337 				 * rsm to nrsm, so the next block
8338 				 * picks it up.
8339 				 */
8340 				nrsm = rack_alloc_limit(rack, RACK_LIMIT_TYPE_SPLIT);
8341 				if (nrsm == NULL) {
8342 					/*
8343 					 * failed XXXrrs what can we do but loose the sack
8344 					 * info?
8345 					 */
8346 					goto out;
8347 				}
8348 				counter_u64_add(rack_sack_splits, 1);
8349 				rack_clone_rsm(rack, nrsm, rsm, start);
8350 				rsm->r_just_ret = 0;
8351 #ifndef INVARIANTS
8352 				(void)RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
8353 #else
8354 				insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
8355 				if (insret != NULL) {
8356 					panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
8357 					      nrsm, insret, rack, rsm);
8358 				}
8359 #endif
8360 				if (rsm->r_in_tmap) {
8361 					TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
8362 					nrsm->r_in_tmap = 1;
8363 				}
8364 				rack_log_map_chg(tp, rack, NULL, rsm, nrsm, MAP_SACK_M2, end, __LINE__);
8365 				rsm->r_flags &= (~RACK_HAS_FIN);
8366 				/* Position us to point to the new nrsm that starts the sack blk */
8367 				rsm = nrsm;
8368 			}
8369 		} else {
8370 			/* Already sacked this piece */
8371 			counter_u64_add(rack_sack_skipped_acked, 1);
8372 			moved++;
8373 			if (end == rsm->r_end) {
8374 				/* Done with block */
8375 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8376 				goto out;
8377 			} else if (SEQ_LT(end, rsm->r_end)) {
8378 				/* A partial sack to a already sacked block */
8379 				moved++;
8380 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8381 				goto out;
8382 			} else {
8383 				/*
8384 				 * The end goes beyond this guy
8385 				 * reposition the start to the
8386 				 * next block.
8387 				 */
8388 				start = rsm->r_end;
8389 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8390 				if (rsm == NULL)
8391 					goto out;
8392 			}
8393 		}
8394 	}
8395 	if (SEQ_GEQ(end, rsm->r_end)) {
8396 		/**
8397 		 * The end of this block is either beyond this guy or right
8398 		 * at this guy. I.e.:
8399 		 *  rsm ---                 |-----|
8400 		 *  end                     |-----|
8401 		 *  <or>
8402 		 *  end                     |---------|
8403 		 */
8404 		if ((rsm->r_flags & RACK_ACKED) == 0) {
8405 			/*
8406 			 * Is it a TLP of interest?
8407 			 */
8408 			if ((rsm->r_flags & RACK_TLP) &&
8409 			    (rsm->r_rtr_cnt > 1)) {
8410 				/*
8411 				 * We are splitting a rxt TLP, check
8412 				 * if we need to save off the start/end
8413 				 */
8414 				if (rack->rc_last_tlp_acked_set &&
8415 				    (is_rsm_inside_declared_tlp_block(rack, rsm))) {
8416 					/*
8417 					 * We already turned this on since we are inside
8418 					 * the previous one was a partially sack now we
8419 					 * are getting another one (maybe all of it).
8420 					 */
8421 					rack_log_dsack_event(rack, 10, __LINE__, rsm->r_start, rsm->r_end);
8422 					/*
8423 					 * Lets make sure we have all of it though.
8424 					 */
8425 					if (SEQ_LT(rsm->r_start, rack->r_ctl.last_tlp_acked_start)) {
8426 						rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8427 						rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8428 								     rack->r_ctl.last_tlp_acked_end);
8429 					}
8430 					if (SEQ_GT(rsm->r_end, rack->r_ctl.last_tlp_acked_end)) {
8431 						rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8432 						rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8433 								     rack->r_ctl.last_tlp_acked_end);
8434 					}
8435 				} else {
8436 					rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8437 					rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8438 					rack->rc_last_tlp_past_cumack = 0;
8439 					rack->rc_last_tlp_acked_set = 1;
8440 					rack_log_dsack_event(rack, 8, __LINE__, rsm->r_start, rsm->r_end);
8441 				}
8442 			}
8443 			rack_update_rtt(tp, rack, rsm, to, cts, SACKED, 0);
8444 			changed += (rsm->r_end - rsm->r_start);
8445 			rack->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start);
8446 			if (rsm->r_in_tmap) /* should be true */
8447 				rack_log_sack_passed(tp, rack, rsm);
8448 			/* Is Reordering occuring? */
8449 			if (rsm->r_flags & RACK_SACK_PASSED) {
8450 				rsm->r_flags &= ~RACK_SACK_PASSED;
8451 				rack->r_ctl.rc_reorder_ts = cts;
8452 			}
8453 			if (rack->app_limited_needs_set)
8454 				rack_need_set_test(tp, rack, rsm, tp->snd_una, __LINE__, RACK_USE_END);
8455 			rsm->r_ack_arrival = rack_to_usec_ts(&rack->r_ctl.act_rcv_time);
8456 			rsm->r_flags |= RACK_ACKED;
8457 			if (rsm->r_in_tmap) {
8458 				TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
8459 				rsm->r_in_tmap = 0;
8460 			}
8461 			rack_log_map_chg(tp, rack, NULL, rsm, NULL, MAP_SACK_M3, end, __LINE__);
8462 		} else {
8463 			counter_u64_add(rack_sack_skipped_acked, 1);
8464 			moved++;
8465 		}
8466 		if (end == rsm->r_end) {
8467 			/* This block only - done, setup for next */
8468 			goto out;
8469 		}
8470 		/*
8471 		 * There is more not coverend by this rsm move on
8472 		 * to the next block in the RB tree.
8473 		 */
8474 		nrsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8475 		start = rsm->r_end;
8476 		rsm = nrsm;
8477 		if (rsm == NULL)
8478 			goto out;
8479 		goto do_rest_ofb;
8480 	}
8481 	/**
8482 	 * The end of this sack block is smaller than
8483 	 * our rsm i.e.:
8484 	 *  rsm ---                 |-----|
8485 	 *  end                     |--|
8486 	 */
8487 	if ((rsm->r_flags & RACK_ACKED) == 0) {
8488 		/*
8489 		 * Is it a TLP of interest?
8490 		 */
8491 		if ((rsm->r_flags & RACK_TLP) &&
8492 		    (rsm->r_rtr_cnt > 1)) {
8493 			/*
8494 			 * We are splitting a rxt TLP, check
8495 			 * if we need to save off the start/end
8496 			 */
8497 			if (rack->rc_last_tlp_acked_set &&
8498 			    (is_rsm_inside_declared_tlp_block(rack, rsm))) {
8499 				/*
8500 				 * We already turned this on since we are inside
8501 				 * the previous one was a partially sack now we
8502 				 * are getting another one (maybe all of it).
8503 				 */
8504 				rack_log_dsack_event(rack, 10, __LINE__, rsm->r_start, rsm->r_end);
8505 				/*
8506 				 * Lets make sure we have all of it though.
8507 				 */
8508 				if (SEQ_LT(rsm->r_start, rack->r_ctl.last_tlp_acked_start)) {
8509 					rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8510 					rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8511 							     rack->r_ctl.last_tlp_acked_end);
8512 				}
8513 				if (SEQ_GT(rsm->r_end, rack->r_ctl.last_tlp_acked_end)) {
8514 					rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8515 					rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8516 							     rack->r_ctl.last_tlp_acked_end);
8517 				}
8518 			} else {
8519 				rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8520 				rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8521 				rack->rc_last_tlp_past_cumack = 0;
8522 				rack->rc_last_tlp_acked_set = 1;
8523 				rack_log_dsack_event(rack, 8, __LINE__, rsm->r_start, rsm->r_end);
8524 			}
8525 		}
8526 		prev = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8527 		if (prev &&
8528 		    (prev->r_flags & RACK_ACKED)) {
8529 			/**
8530 			 * Goal, we want the right remainder of rsm to shrink
8531 			 * in place and span from (rsm->r_start = end) to rsm->r_end.
8532 			 * We want to expand prev to go all the way
8533 			 * to prev->r_end <- end.
8534 			 * so in the tree we have before:
8535 			 *   prev     |--------|         (acked)
8536 			 *   rsm               |-------| (non-acked)
8537 			 *   sackblk           |-|
8538 			 * We churn it so we end up with
8539 			 *   prev     |----------|       (acked)
8540 			 *   rsm                 |-----| (non-acked)
8541 			 *   nrsm              |-| (temporary)
8542 			 *
8543 			 * Note if either prev/rsm is a TLP we don't
8544 			 * do this.
8545 			 */
8546 			nrsm = &stack_map;
8547 			memcpy(nrsm, rsm, sizeof(struct rack_sendmap));
8548 			prev->r_end = end;
8549 			rsm->r_start = end;
8550 			/* Now adjust nrsm (stack copy) to be
8551 			 * the one that is the small
8552 			 * piece that was "sacked".
8553 			 */
8554 			nrsm->r_end = end;
8555 			rsm->r_dupack = 0;
8556 			rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
8557 			/*
8558 			 * Now that the rsm has had its start moved forward
8559 			 * lets go ahead and get its new place in the world.
8560 			 */
8561 			rack_setup_offset_for_rsm(prev, rsm);
8562 			/*
8563 			 * Now nrsm is our new little piece
8564 			 * that is acked (which was merged
8565 			 * to prev). Update the rtt and changed
8566 			 * based on that. Also check for reordering.
8567 			 */
8568 			rack_update_rtt(tp, rack, nrsm, to, cts, SACKED, 0);
8569 			if (rack->app_limited_needs_set)
8570 				rack_need_set_test(tp, rack, nrsm, tp->snd_una, __LINE__, RACK_USE_END);
8571 			changed += (nrsm->r_end - nrsm->r_start);
8572 			rack->r_ctl.rc_sacked += (nrsm->r_end - nrsm->r_start);
8573 			if (nrsm->r_flags & RACK_SACK_PASSED) {
8574 				rack->r_ctl.rc_reorder_ts = cts;
8575 			}
8576 			rack_log_map_chg(tp, rack, prev, &stack_map, rsm, MAP_SACK_M4, end, __LINE__);
8577 			rsm = prev;
8578 			counter_u64_add(rack_sack_used_prev_merge, 1);
8579 		} else {
8580 			/**
8581 			 * This is the case where our previous
8582 			 * block is not acked either, so we must
8583 			 * split the block in two.
8584 			 */
8585 			nrsm = rack_alloc_limit(rack, RACK_LIMIT_TYPE_SPLIT);
8586 			if (nrsm == NULL) {
8587 				/* failed rrs what can we do but loose the sack info? */
8588 				goto out;
8589 			}
8590 			if ((rsm->r_flags & RACK_TLP) &&
8591 			    (rsm->r_rtr_cnt > 1)) {
8592 				/*
8593 				 * We are splitting a rxt TLP, check
8594 				 * if we need to save off the start/end
8595 				 */
8596 				if (rack->rc_last_tlp_acked_set &&
8597 				    (is_rsm_inside_declared_tlp_block(rack, rsm))) {
8598 					    /*
8599 					     * We already turned this on since this block is inside
8600 					     * the previous one was a partially sack now we
8601 					     * are getting another one (maybe all of it).
8602 					     */
8603 					    rack_log_dsack_event(rack, 10, __LINE__, rsm->r_start, rsm->r_end);
8604 					    /*
8605 					     * Lets make sure we have all of it though.
8606 					     */
8607 					    if (SEQ_LT(rsm->r_start, rack->r_ctl.last_tlp_acked_start)) {
8608 						    rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8609 						    rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8610 									 rack->r_ctl.last_tlp_acked_end);
8611 					    }
8612 					    if (SEQ_GT(rsm->r_end, rack->r_ctl.last_tlp_acked_end)) {
8613 						    rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8614 						    rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8615 									 rack->r_ctl.last_tlp_acked_end);
8616 					    }
8617 				    } else {
8618 					    rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8619 					    rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8620 					    rack->rc_last_tlp_acked_set = 1;
8621 					    rack->rc_last_tlp_past_cumack = 0;
8622 					    rack_log_dsack_event(rack, 8, __LINE__, rsm->r_start, rsm->r_end);
8623 				    }
8624 			}
8625 			/**
8626 			 * In this case nrsm becomes
8627 			 * nrsm->r_start = end;
8628 			 * nrsm->r_end = rsm->r_end;
8629 			 * which is un-acked.
8630 			 * <and>
8631 			 * rsm->r_end = nrsm->r_start;
8632 			 * i.e. the remaining un-acked
8633 			 * piece is left on the left
8634 			 * hand side.
8635 			 *
8636 			 * So we start like this
8637 			 * rsm      |----------| (not acked)
8638 			 * sackblk  |---|
8639 			 * build it so we have
8640 			 * rsm      |---|         (acked)
8641 			 * nrsm         |------|  (not acked)
8642 			 */
8643 			counter_u64_add(rack_sack_splits, 1);
8644 			rack_clone_rsm(rack, nrsm, rsm, end);
8645 			rsm->r_flags &= (~RACK_HAS_FIN);
8646 			rsm->r_just_ret = 0;
8647 #ifndef INVARIANTS
8648 			(void)RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
8649 #else
8650 			insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
8651 			if (insret != NULL) {
8652 				panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
8653 				      nrsm, insret, rack, rsm);
8654 			}
8655 #endif
8656 			if (rsm->r_in_tmap) {
8657 				TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
8658 				nrsm->r_in_tmap = 1;
8659 			}
8660 			nrsm->r_dupack = 0;
8661 			rack_log_retran_reason(rack, nrsm, __LINE__, 0, 2);
8662 			rack_update_rtt(tp, rack, rsm, to, cts, SACKED, 0);
8663 			changed += (rsm->r_end - rsm->r_start);
8664 			rack->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start);
8665 			if (rsm->r_in_tmap) /* should be true */
8666 				rack_log_sack_passed(tp, rack, rsm);
8667 			/* Is Reordering occuring? */
8668 			if (rsm->r_flags & RACK_SACK_PASSED) {
8669 				rsm->r_flags &= ~RACK_SACK_PASSED;
8670 				rack->r_ctl.rc_reorder_ts = cts;
8671 			}
8672 			if (rack->app_limited_needs_set)
8673 				rack_need_set_test(tp, rack, rsm, tp->snd_una, __LINE__, RACK_USE_END);
8674 			rsm->r_ack_arrival = rack_to_usec_ts(&rack->r_ctl.act_rcv_time);
8675 			rsm->r_flags |= RACK_ACKED;
8676 			rack_log_map_chg(tp, rack, NULL, rsm, nrsm, MAP_SACK_M5, end, __LINE__);
8677 			if (rsm->r_in_tmap) {
8678 				TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
8679 				rsm->r_in_tmap = 0;
8680 			}
8681 		}
8682 	} else if (start != end){
8683 		/*
8684 		 * The block was already acked.
8685 		 */
8686 		counter_u64_add(rack_sack_skipped_acked, 1);
8687 		moved++;
8688 	}
8689 out:
8690 	if (rsm &&
8691 	    ((rsm->r_flags & RACK_TLP) == 0) &&
8692 	    (rsm->r_flags & RACK_ACKED)) {
8693 		/*
8694 		 * Now can we merge where we worked
8695 		 * with either the previous or
8696 		 * next block?
8697 		 */
8698 		next = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8699 		while (next) {
8700 			if (next->r_flags & RACK_TLP)
8701 				break;
8702 			if (next->r_flags & RACK_ACKED) {
8703 			/* yep this and next can be merged */
8704 				rsm = rack_merge_rsm(rack, rsm, next);
8705 				next = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8706 			} else
8707 				break;
8708 		}
8709 		/* Now what about the previous? */
8710 		prev = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8711 		while (prev) {
8712 			if (prev->r_flags & RACK_TLP)
8713 				break;
8714 			if (prev->r_flags & RACK_ACKED) {
8715 				/* yep the previous and this can be merged */
8716 				rsm = rack_merge_rsm(rack, prev, rsm);
8717 				prev = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8718 			} else
8719 				break;
8720 		}
8721 	}
8722 	if (used_ref == 0) {
8723 		counter_u64_add(rack_sack_proc_all, 1);
8724 	} else {
8725 		counter_u64_add(rack_sack_proc_short, 1);
8726 	}
8727 	/* Save off the next one for quick reference. */
8728 	if (rsm)
8729 		nrsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8730 	else
8731 		nrsm = NULL;
8732 	*prsm = rack->r_ctl.rc_sacklast = nrsm;
8733 	/* Pass back the moved. */
8734 	*moved_two = moved;
8735 	return (changed);
8736 }
8737 
8738 static void inline
8739 rack_peer_reneges(struct tcp_rack *rack, struct rack_sendmap *rsm, tcp_seq th_ack)
8740 {
8741 	struct rack_sendmap *tmap;
8742 
8743 	tmap = NULL;
8744 	while (rsm && (rsm->r_flags & RACK_ACKED)) {
8745 		/* Its no longer sacked, mark it so */
8746 		rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
8747 #ifdef INVARIANTS
8748 		if (rsm->r_in_tmap) {
8749 			panic("rack:%p rsm:%p flags:0x%x in tmap?",
8750 			      rack, rsm, rsm->r_flags);
8751 		}
8752 #endif
8753 		rsm->r_flags &= ~(RACK_ACKED|RACK_SACK_PASSED|RACK_WAS_SACKPASS);
8754 		/* Rebuild it into our tmap */
8755 		if (tmap == NULL) {
8756 			TAILQ_INSERT_HEAD(&rack->r_ctl.rc_tmap, rsm, r_tnext);
8757 			tmap = rsm;
8758 		} else {
8759 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, tmap, rsm, r_tnext);
8760 			tmap = rsm;
8761 		}
8762 		tmap->r_in_tmap = 1;
8763 		rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8764 	}
8765 	/*
8766 	 * Now lets possibly clear the sack filter so we start
8767 	 * recognizing sacks that cover this area.
8768 	 */
8769 	sack_filter_clear(&rack->r_ctl.rack_sf, th_ack);
8770 
8771 }
8772 
8773 static void
8774 rack_do_decay(struct tcp_rack *rack)
8775 {
8776 	struct timeval res;
8777 
8778 #define	timersub(tvp, uvp, vvp)						\
8779 	do {								\
8780 		(vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec;		\
8781 		(vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec;	\
8782 		if ((vvp)->tv_usec < 0) {				\
8783 			(vvp)->tv_sec--;				\
8784 			(vvp)->tv_usec += 1000000;			\
8785 		}							\
8786 	} while (0)
8787 
8788 	timersub(&rack->r_ctl.act_rcv_time, &rack->r_ctl.rc_last_time_decay, &res);
8789 #undef timersub
8790 
8791 	rack->r_ctl.input_pkt++;
8792 	if ((rack->rc_in_persist) ||
8793 	    (res.tv_sec >= 1) ||
8794 	    (rack->rc_tp->snd_max == rack->rc_tp->snd_una)) {
8795 		/*
8796 		 * Check for decay of non-SAD,
8797 		 * we want all SAD detection metrics to
8798 		 * decay 1/4 per second (or more) passed.
8799 		 */
8800 #ifdef NETFLIX_EXP_DETECTION
8801 		uint32_t pkt_delta;
8802 
8803 		pkt_delta = rack->r_ctl.input_pkt - rack->r_ctl.saved_input_pkt;
8804 #endif
8805 		/* Update our saved tracking values */
8806 		rack->r_ctl.saved_input_pkt = rack->r_ctl.input_pkt;
8807 		rack->r_ctl.rc_last_time_decay = rack->r_ctl.act_rcv_time;
8808 		/* Now do we escape without decay? */
8809 #ifdef NETFLIX_EXP_DETECTION
8810 		if (rack->rc_in_persist ||
8811 		    (rack->rc_tp->snd_max == rack->rc_tp->snd_una) ||
8812 		    (pkt_delta < tcp_sad_low_pps)){
8813 			/*
8814 			 * We don't decay idle connections
8815 			 * or ones that have a low input pps.
8816 			 */
8817 			return;
8818 		}
8819 		/* Decay the counters */
8820 		rack->r_ctl.ack_count = ctf_decay_count(rack->r_ctl.ack_count,
8821 							tcp_sad_decay_val);
8822 		rack->r_ctl.sack_count = ctf_decay_count(rack->r_ctl.sack_count,
8823 							 tcp_sad_decay_val);
8824 		rack->r_ctl.sack_moved_extra = ctf_decay_count(rack->r_ctl.sack_moved_extra,
8825 							       tcp_sad_decay_val);
8826 		rack->r_ctl.sack_noextra_move = ctf_decay_count(rack->r_ctl.sack_noextra_move,
8827 								tcp_sad_decay_val);
8828 #endif
8829 	}
8830 }
8831 
8832 static void
8833 rack_process_to_cumack(struct tcpcb *tp, struct tcp_rack *rack, register uint32_t th_ack, uint32_t cts, struct tcpopt *to)
8834 {
8835 	struct rack_sendmap *rsm;
8836 #ifdef INVARIANTS
8837 	struct rack_sendmap *rm;
8838 #endif
8839 
8840 	/*
8841 	 * The ACK point is advancing to th_ack, we must drop off
8842 	 * the packets in the rack log and calculate any eligble
8843 	 * RTT's.
8844 	 */
8845 	rack->r_wanted_output = 1;
8846 
8847 	/* Tend any TLP that has been marked for 1/2 the seq space (its old)  */
8848 	if ((rack->rc_last_tlp_acked_set == 1)&&
8849 	    (rack->rc_last_tlp_past_cumack == 1) &&
8850 	    (SEQ_GT(rack->r_ctl.last_tlp_acked_start, th_ack))) {
8851 		/*
8852 		 * We have reached the point where our last rack
8853 		 * tlp retransmit sequence is ahead of the cum-ack.
8854 		 * This can only happen when the cum-ack moves all
8855 		 * the way around (its been a full 2^^31+1 bytes
8856 		 * or more since we sent a retransmitted TLP). Lets
8857 		 * turn off the valid flag since its not really valid.
8858 		 *
8859 		 * Note since sack's also turn on this event we have
8860 		 * a complication, we have to wait to age it out until
8861 		 * the cum-ack is by the TLP before checking which is
8862 		 * what the next else clause does.
8863 		 */
8864 		rack_log_dsack_event(rack, 9, __LINE__,
8865 				     rack->r_ctl.last_tlp_acked_start,
8866 				     rack->r_ctl.last_tlp_acked_end);
8867 		rack->rc_last_tlp_acked_set = 0;
8868 		rack->rc_last_tlp_past_cumack = 0;
8869 	} else if ((rack->rc_last_tlp_acked_set == 1) &&
8870 		   (rack->rc_last_tlp_past_cumack == 0) &&
8871 		   (SEQ_GEQ(th_ack, rack->r_ctl.last_tlp_acked_end))) {
8872 		/*
8873 		 * It is safe to start aging TLP's out.
8874 		 */
8875 		rack->rc_last_tlp_past_cumack = 1;
8876 	}
8877 	/* We do the same for the tlp send seq as well */
8878 	if ((rack->rc_last_sent_tlp_seq_valid == 1) &&
8879 	    (rack->rc_last_sent_tlp_past_cumack == 1) &&
8880 	    (SEQ_GT(rack->r_ctl.last_sent_tlp_seq,  th_ack))) {
8881 		rack_log_dsack_event(rack, 9, __LINE__,
8882 				     rack->r_ctl.last_sent_tlp_seq,
8883 				     (rack->r_ctl.last_sent_tlp_seq +
8884 				      rack->r_ctl.last_sent_tlp_len));
8885 		rack->rc_last_sent_tlp_seq_valid = 0;
8886 		rack->rc_last_sent_tlp_past_cumack = 0;
8887 	} else if ((rack->rc_last_sent_tlp_seq_valid == 1) &&
8888 		   (rack->rc_last_sent_tlp_past_cumack == 0) &&
8889 		   (SEQ_GEQ(th_ack, rack->r_ctl.last_sent_tlp_seq))) {
8890 		/*
8891 		 * It is safe to start aging TLP's send.
8892 		 */
8893 		rack->rc_last_sent_tlp_past_cumack = 1;
8894 	}
8895 more:
8896 	rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
8897 	if (rsm == NULL) {
8898 		if ((th_ack - 1) == tp->iss) {
8899 			/*
8900 			 * For the SYN incoming case we will not
8901 			 * have called tcp_output for the sending of
8902 			 * the SYN, so there will be no map. All
8903 			 * other cases should probably be a panic.
8904 			 */
8905 			return;
8906 		}
8907 		if (tp->t_flags & TF_SENTFIN) {
8908 			/* if we sent a FIN we often will not have map */
8909 			return;
8910 		}
8911 #ifdef INVARIANTS
8912 		panic("No rack map tp:%p for state:%d ack:%u rack:%p snd_una:%u snd_max:%u snd_nxt:%u\n",
8913 		      tp,
8914 		      tp->t_state, th_ack, rack,
8915 		      tp->snd_una, tp->snd_max, tp->snd_nxt);
8916 #endif
8917 		return;
8918 	}
8919 	if (SEQ_LT(th_ack, rsm->r_start)) {
8920 		/* Huh map is missing this */
8921 #ifdef INVARIANTS
8922 		printf("Rack map starts at r_start:%u for th_ack:%u huh? ts:%d rs:%d\n",
8923 		       rsm->r_start,
8924 		       th_ack, tp->t_state, rack->r_state);
8925 #endif
8926 		return;
8927 	}
8928 	rack_update_rtt(tp, rack, rsm, to, cts, CUM_ACKED, th_ack);
8929 
8930 	/* Now was it a retransmitted TLP? */
8931 	if ((rsm->r_flags & RACK_TLP) &&
8932 	    (rsm->r_rtr_cnt > 1)) {
8933 		/*
8934 		 * Yes, this rsm was a TLP and retransmitted, remember that
8935 		 * since if a DSACK comes back on this we don't want
8936 		 * to think of it as a reordered segment. This may
8937 		 * get updated again with possibly even other TLPs
8938 		 * in flight, but thats ok. Only when we don't send
8939 		 * a retransmitted TLP for 1/2 the sequences space
8940 		 * will it get turned off (above).
8941 		 */
8942 		if (rack->rc_last_tlp_acked_set &&
8943 		    (is_rsm_inside_declared_tlp_block(rack, rsm))) {
8944 			/*
8945 			 * We already turned this on since the end matches,
8946 			 * the previous one was a partially ack now we
8947 			 * are getting another one (maybe all of it).
8948 			 */
8949 			rack_log_dsack_event(rack, 10, __LINE__, rsm->r_start, rsm->r_end);
8950 			/*
8951 			 * Lets make sure we have all of it though.
8952 			 */
8953 			if (SEQ_LT(rsm->r_start, rack->r_ctl.last_tlp_acked_start)) {
8954 				rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8955 				rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8956 						     rack->r_ctl.last_tlp_acked_end);
8957 			}
8958 			if (SEQ_GT(rsm->r_end, rack->r_ctl.last_tlp_acked_end)) {
8959 				rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8960 				rack_log_dsack_event(rack, 11, __LINE__, rack->r_ctl.last_tlp_acked_start,
8961 						     rack->r_ctl.last_tlp_acked_end);
8962 			}
8963 		} else {
8964 			rack->rc_last_tlp_past_cumack = 1;
8965 			rack->r_ctl.last_tlp_acked_start = rsm->r_start;
8966 			rack->r_ctl.last_tlp_acked_end = rsm->r_end;
8967 			rack->rc_last_tlp_acked_set = 1;
8968 			rack_log_dsack_event(rack, 8, __LINE__, rsm->r_start, rsm->r_end);
8969 		}
8970 	}
8971 	/* Now do we consume the whole thing? */
8972 	if (SEQ_GEQ(th_ack, rsm->r_end)) {
8973 		/* Its all consumed. */
8974 		uint32_t left;
8975 		uint8_t newly_acked;
8976 
8977 		rack_log_map_chg(tp, rack, NULL, rsm, NULL, MAP_FREE, rsm->r_end, __LINE__);
8978 		rack->r_ctl.rc_holes_rxt -= rsm->r_rtr_bytes;
8979 		rsm->r_rtr_bytes = 0;
8980 		/* Record the time of highest cumack sent */
8981 		rack->r_ctl.rc_gp_cumack_ts = rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
8982 #ifndef INVARIANTS
8983 		(void)RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8984 #else
8985 		rm = RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
8986 		if (rm != rsm) {
8987 			panic("removing head in rack:%p rsm:%p rm:%p",
8988 			      rack, rsm, rm);
8989 		}
8990 #endif
8991 		if (rsm->r_in_tmap) {
8992 			TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
8993 			rsm->r_in_tmap = 0;
8994 		}
8995 		newly_acked = 1;
8996 		if (rsm->r_flags & RACK_ACKED) {
8997 			/*
8998 			 * It was acked on the scoreboard -- remove
8999 			 * it from total
9000 			 */
9001 			rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
9002 			newly_acked = 0;
9003 		} else if (rsm->r_flags & RACK_SACK_PASSED) {
9004 			/*
9005 			 * There are segments ACKED on the
9006 			 * scoreboard further up. We are seeing
9007 			 * reordering.
9008 			 */
9009 			rsm->r_flags &= ~RACK_SACK_PASSED;
9010 			rsm->r_ack_arrival = rack_to_usec_ts(&rack->r_ctl.act_rcv_time);
9011 			rsm->r_flags |= RACK_ACKED;
9012 			rack->r_ctl.rc_reorder_ts = cts;
9013 			if (rack->r_ent_rec_ns) {
9014 				/*
9015 				 * We have sent no more, and we saw an sack
9016 				 * then ack arrive.
9017 				 */
9018 				rack->r_might_revert = 1;
9019 			}
9020 		}
9021 		if ((rsm->r_flags & RACK_TO_REXT) &&
9022 		    (tp->t_flags & TF_RCVD_TSTMP) &&
9023 		    (to->to_flags & TOF_TS) &&
9024 		    (to->to_tsecr != 0) &&
9025 		    (tp->t_flags & TF_PREVVALID)) {
9026 			/*
9027 			 * We can use the timestamp to see
9028 			 * if this retransmission was from the
9029 			 * first transmit. If so we made a mistake.
9030 			 */
9031 			tp->t_flags &= ~TF_PREVVALID;
9032 			if (to->to_tsecr == rack_ts_to_msec(rsm->r_tim_lastsent[0])) {
9033 				/* The first transmit is what this ack is for */
9034 				rack_cong_signal(tp, CC_RTO_ERR, th_ack, __LINE__);
9035 			}
9036 		}
9037 		left = th_ack - rsm->r_end;
9038 		if (rack->app_limited_needs_set && newly_acked)
9039 			rack_need_set_test(tp, rack, rsm, th_ack, __LINE__, RACK_USE_END_OR_THACK);
9040 		/* Free back to zone */
9041 		rack_free(rack, rsm);
9042 		if (left) {
9043 			goto more;
9044 		}
9045 		/* Check for reneging */
9046 		rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
9047 		if (rsm && (rsm->r_flags & RACK_ACKED) && (th_ack == rsm->r_start)) {
9048 			/*
9049 			 * The peer has moved snd_una up to
9050 			 * the edge of this send, i.e. one
9051 			 * that it had previously acked. The only
9052 			 * way that can be true if the peer threw
9053 			 * away data (space issues) that it had
9054 			 * previously sacked (else it would have
9055 			 * given us snd_una up to (rsm->r_end).
9056 			 * We need to undo the acked markings here.
9057 			 *
9058 			 * Note we have to look to make sure th_ack is
9059 			 * our rsm->r_start in case we get an old ack
9060 			 * where th_ack is behind snd_una.
9061 			 */
9062 			rack_peer_reneges(rack, rsm, th_ack);
9063 		}
9064 		return;
9065 	}
9066 	if (rsm->r_flags & RACK_ACKED) {
9067 		/*
9068 		 * It was acked on the scoreboard -- remove it from
9069 		 * total for the part being cum-acked.
9070 		 */
9071 		rack->r_ctl.rc_sacked -= (th_ack - rsm->r_start);
9072 	}
9073 	/*
9074 	 * Clear the dup ack count for
9075 	 * the piece that remains.
9076 	 */
9077 	rsm->r_dupack = 0;
9078 	rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
9079 	if (rsm->r_rtr_bytes) {
9080 		/*
9081 		 * It was retransmitted adjust the
9082 		 * sack holes for what was acked.
9083 		 */
9084 		int ack_am;
9085 
9086 		ack_am = (th_ack - rsm->r_start);
9087 		if (ack_am >= rsm->r_rtr_bytes) {
9088 			rack->r_ctl.rc_holes_rxt -= ack_am;
9089 			rsm->r_rtr_bytes -= ack_am;
9090 		}
9091 	}
9092 	/*
9093 	 * Update where the piece starts and record
9094 	 * the time of send of highest cumack sent.
9095 	 */
9096 	rack->r_ctl.rc_gp_cumack_ts = rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)];
9097 	rack_log_map_chg(tp, rack, NULL, rsm, NULL, MAP_TRIM_HEAD, th_ack, __LINE__);
9098 	/* Now we need to move our offset forward too */
9099 	if (rsm->m && (rsm->orig_m_len != rsm->m->m_len)) {
9100 		/* Fix up the orig_m_len and possibly the mbuf offset */
9101 		rack_adjust_orig_mlen(rsm);
9102 	}
9103 	rsm->soff += (th_ack - rsm->r_start);
9104 	rsm->r_start = th_ack;
9105 	/* Now do we need to move the mbuf fwd too? */
9106 	if (rsm->m) {
9107 		while (rsm->soff >= rsm->m->m_len) {
9108 			rsm->soff -= rsm->m->m_len;
9109 			rsm->m = rsm->m->m_next;
9110 			KASSERT((rsm->m != NULL),
9111 				(" nrsm:%p hit at soff:%u null m",
9112 				 rsm, rsm->soff));
9113 		}
9114 		rsm->orig_m_len = rsm->m->m_len;
9115 	}
9116 	if (rack->app_limited_needs_set)
9117 		rack_need_set_test(tp, rack, rsm, tp->snd_una, __LINE__, RACK_USE_BEG);
9118 }
9119 
9120 static void
9121 rack_handle_might_revert(struct tcpcb *tp, struct tcp_rack *rack)
9122 {
9123 	struct rack_sendmap *rsm;
9124 	int sack_pass_fnd = 0;
9125 
9126 	if (rack->r_might_revert) {
9127 		/*
9128 		 * Ok we have reordering, have not sent anything, we
9129 		 * might want to revert the congestion state if nothing
9130 		 * further has SACK_PASSED on it. Lets check.
9131 		 *
9132 		 * We also get here when we have DSACKs come in for
9133 		 * all the data that we FR'd. Note that a rxt or tlp
9134 		 * timer clears this from happening.
9135 		 */
9136 
9137 		TAILQ_FOREACH(rsm, &rack->r_ctl.rc_tmap, r_tnext) {
9138 			if (rsm->r_flags & RACK_SACK_PASSED) {
9139 				sack_pass_fnd = 1;
9140 				break;
9141 			}
9142 		}
9143 		if (sack_pass_fnd == 0) {
9144 			/*
9145 			 * We went into recovery
9146 			 * incorrectly due to reordering!
9147 			 */
9148 			int orig_cwnd;
9149 
9150 			rack->r_ent_rec_ns = 0;
9151 			orig_cwnd = tp->snd_cwnd;
9152 			tp->snd_ssthresh = rack->r_ctl.rc_ssthresh_at_erec;
9153 			tp->snd_recover = tp->snd_una;
9154 			rack_log_to_prr(rack, 14, orig_cwnd, __LINE__);
9155 			EXIT_RECOVERY(tp->t_flags);
9156 		}
9157 		rack->r_might_revert = 0;
9158 	}
9159 }
9160 
9161 #ifdef NETFLIX_EXP_DETECTION
9162 static void
9163 rack_do_detection(struct tcpcb *tp, struct tcp_rack *rack,  uint32_t bytes_this_ack, uint32_t segsiz)
9164 {
9165 	if ((rack->do_detection || tcp_force_detection) &&
9166 	    tcp_sack_to_ack_thresh &&
9167 	    tcp_sack_to_move_thresh &&
9168 	    ((rack->r_ctl.rc_num_maps_alloced > tcp_map_minimum) || rack->sack_attack_disable)) {
9169 		/*
9170 		 * We have thresholds set to find
9171 		 * possible attackers and disable sack.
9172 		 * Check them.
9173 		 */
9174 		uint64_t ackratio, moveratio, movetotal;
9175 
9176 		/* Log detecting */
9177 		rack_log_sad(rack, 1);
9178 		ackratio = (uint64_t)(rack->r_ctl.sack_count);
9179 		ackratio *= (uint64_t)(1000);
9180 		if (rack->r_ctl.ack_count)
9181 			ackratio /= (uint64_t)(rack->r_ctl.ack_count);
9182 		else {
9183 			/* We really should not hit here */
9184 			ackratio = 1000;
9185 		}
9186 		if ((rack->sack_attack_disable == 0) &&
9187 		    (ackratio > rack_highest_sack_thresh_seen))
9188 			rack_highest_sack_thresh_seen = (uint32_t)ackratio;
9189 		movetotal = rack->r_ctl.sack_moved_extra;
9190 		movetotal += rack->r_ctl.sack_noextra_move;
9191 		moveratio = rack->r_ctl.sack_moved_extra;
9192 		moveratio *= (uint64_t)1000;
9193 		if (movetotal)
9194 			moveratio /= movetotal;
9195 		else {
9196 			/* No moves, thats pretty good */
9197 			moveratio = 0;
9198 		}
9199 		if ((rack->sack_attack_disable == 0) &&
9200 		    (moveratio > rack_highest_move_thresh_seen))
9201 			rack_highest_move_thresh_seen = (uint32_t)moveratio;
9202 		if (rack->sack_attack_disable == 0) {
9203 			if ((ackratio > tcp_sack_to_ack_thresh) &&
9204 			    (moveratio > tcp_sack_to_move_thresh)) {
9205 				/* Disable sack processing */
9206 				rack->sack_attack_disable = 1;
9207 				if (rack->r_rep_attack == 0) {
9208 					rack->r_rep_attack = 1;
9209 					counter_u64_add(rack_sack_attacks_detected, 1);
9210 				}
9211 				if (tcp_attack_on_turns_on_logging) {
9212 					/*
9213 					 * Turn on logging, used for debugging
9214 					 * false positives.
9215 					 */
9216 					rack->rc_tp->t_logstate = tcp_attack_on_turns_on_logging;
9217 				}
9218 				/* Clamp the cwnd at flight size */
9219 				rack->r_ctl.rc_saved_cwnd = rack->rc_tp->snd_cwnd;
9220 				rack->rc_tp->snd_cwnd = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
9221 				rack_log_sad(rack, 2);
9222 			}
9223 		} else {
9224 			/* We are sack-disabled check for false positives */
9225 			if ((ackratio <= tcp_restoral_thresh) ||
9226 			    (rack->r_ctl.rc_num_maps_alloced  < tcp_map_minimum)) {
9227 				rack->sack_attack_disable = 0;
9228 				rack_log_sad(rack, 3);
9229 				/* Restart counting */
9230 				rack->r_ctl.sack_count = 0;
9231 				rack->r_ctl.sack_moved_extra = 0;
9232 				rack->r_ctl.sack_noextra_move = 1;
9233 				rack->r_ctl.ack_count = max(1,
9234 				      (bytes_this_ack / segsiz));
9235 
9236 				if (rack->r_rep_reverse == 0) {
9237 					rack->r_rep_reverse = 1;
9238 					counter_u64_add(rack_sack_attacks_reversed, 1);
9239 				}
9240 				/* Restore the cwnd */
9241 				if (rack->r_ctl.rc_saved_cwnd > rack->rc_tp->snd_cwnd)
9242 					rack->rc_tp->snd_cwnd = rack->r_ctl.rc_saved_cwnd;
9243 			}
9244 		}
9245 	}
9246 }
9247 #endif
9248 
9249 static int
9250 rack_note_dsack(struct tcp_rack *rack, tcp_seq start, tcp_seq end)
9251 {
9252 
9253 	uint32_t am, l_end;
9254 	int was_tlp = 0;
9255 
9256 	if (SEQ_GT(end, start))
9257 		am = end - start;
9258 	else
9259 		am = 0;
9260 	if ((rack->rc_last_tlp_acked_set ) &&
9261 	    (SEQ_GEQ(start, rack->r_ctl.last_tlp_acked_start)) &&
9262 	    (SEQ_LEQ(end, rack->r_ctl.last_tlp_acked_end))) {
9263 		/*
9264 		 * The DSACK is because of a TLP which we don't
9265 		 * do anything with the reordering window over since
9266 		 * it was not reordering that caused the DSACK but
9267 		 * our previous retransmit TLP.
9268 		 */
9269 		rack_log_dsack_event(rack, 7, __LINE__, start, end);
9270 		was_tlp = 1;
9271 		goto skip_dsack_round;
9272 	}
9273 	if (rack->rc_last_sent_tlp_seq_valid) {
9274 		l_end = rack->r_ctl.last_sent_tlp_seq + rack->r_ctl.last_sent_tlp_len;
9275 		if (SEQ_GEQ(start, rack->r_ctl.last_sent_tlp_seq) &&
9276 		    (SEQ_LEQ(end, l_end))) {
9277 			/*
9278 			 * This dsack is from the last sent TLP, ignore it
9279 			 * for reordering purposes.
9280 			 */
9281 			rack_log_dsack_event(rack, 7, __LINE__, start, end);
9282 			was_tlp = 1;
9283 			goto skip_dsack_round;
9284 		}
9285 	}
9286 	if (rack->rc_dsack_round_seen == 0) {
9287 		rack->rc_dsack_round_seen = 1;
9288 		rack->r_ctl.dsack_round_end = rack->rc_tp->snd_max;
9289 		rack->r_ctl.num_dsack++;
9290 		rack->r_ctl.dsack_persist = 16;	/* 16 is from the standard */
9291 		rack_log_dsack_event(rack, 2, __LINE__, 0, 0);
9292 	}
9293 skip_dsack_round:
9294 	/*
9295 	 * We keep track of how many DSACK blocks we get
9296 	 * after a recovery incident.
9297 	 */
9298 	rack->r_ctl.dsack_byte_cnt += am;
9299 	if (!IN_FASTRECOVERY(rack->rc_tp->t_flags) &&
9300 	    rack->r_ctl.retran_during_recovery &&
9301 	    (rack->r_ctl.dsack_byte_cnt >= rack->r_ctl.retran_during_recovery)) {
9302 		/*
9303 		 * False recovery most likely culprit is reordering. If
9304 		 * nothing else is missing we need to revert.
9305 		 */
9306 		rack->r_might_revert = 1;
9307 		rack_handle_might_revert(rack->rc_tp, rack);
9308 		rack->r_might_revert = 0;
9309 		rack->r_ctl.retran_during_recovery = 0;
9310 		rack->r_ctl.dsack_byte_cnt = 0;
9311 	}
9312 	return (was_tlp);
9313 }
9314 
9315 static uint32_t
9316 do_rack_compute_pipe(struct tcpcb *tp, struct tcp_rack *rack, uint32_t snd_una)
9317 {
9318 	return (((tp->snd_max - snd_una) - rack->r_ctl.rc_sacked) + rack->r_ctl.rc_holes_rxt);
9319 }
9320 
9321 static int32_t
9322 rack_compute_pipe(struct tcpcb *tp)
9323 {
9324 	return ((int32_t)do_rack_compute_pipe(tp,
9325 					      (struct tcp_rack *)tp->t_fb_ptr,
9326 					      tp->snd_una));
9327 }
9328 
9329 static void
9330 rack_update_prr(struct tcpcb *tp, struct tcp_rack *rack, uint32_t changed, tcp_seq th_ack)
9331 {
9332 	/* Deal with changed and PRR here (in recovery only) */
9333 	uint32_t pipe, snd_una;
9334 
9335 	rack->r_ctl.rc_prr_delivered += changed;
9336 
9337 	if (sbavail(&rack->rc_inp->inp_socket->so_snd) <= (tp->snd_max - tp->snd_una)) {
9338 		/*
9339 		 * It is all outstanding, we are application limited
9340 		 * and thus we don't need more room to send anything.
9341 		 * Note we use tp->snd_una here and not th_ack because
9342 		 * the data as yet not been cut from the sb.
9343 		 */
9344 		rack->r_ctl.rc_prr_sndcnt = 0;
9345 		return;
9346 	}
9347 	/* Compute prr_sndcnt */
9348 	if (SEQ_GT(tp->snd_una, th_ack)) {
9349 		snd_una = tp->snd_una;
9350 	} else {
9351 		snd_una = th_ack;
9352 	}
9353 	pipe = do_rack_compute_pipe(tp, rack, snd_una);
9354 	if (pipe > tp->snd_ssthresh) {
9355 		long sndcnt;
9356 
9357 		sndcnt = rack->r_ctl.rc_prr_delivered * tp->snd_ssthresh;
9358 		if (rack->r_ctl.rc_prr_recovery_fs > 0)
9359 			sndcnt /= (long)rack->r_ctl.rc_prr_recovery_fs;
9360 		else {
9361 			rack->r_ctl.rc_prr_sndcnt = 0;
9362 			rack_log_to_prr(rack, 9, 0, __LINE__);
9363 			sndcnt = 0;
9364 		}
9365 		sndcnt++;
9366 		if (sndcnt > (long)rack->r_ctl.rc_prr_out)
9367 			sndcnt -= rack->r_ctl.rc_prr_out;
9368 		else
9369 			sndcnt = 0;
9370 		rack->r_ctl.rc_prr_sndcnt = sndcnt;
9371 		rack_log_to_prr(rack, 10, 0, __LINE__);
9372 	} else {
9373 		uint32_t limit;
9374 
9375 		if (rack->r_ctl.rc_prr_delivered > rack->r_ctl.rc_prr_out)
9376 			limit = (rack->r_ctl.rc_prr_delivered - rack->r_ctl.rc_prr_out);
9377 		else
9378 			limit = 0;
9379 		if (changed > limit)
9380 			limit = changed;
9381 		limit += ctf_fixed_maxseg(tp);
9382 		if (tp->snd_ssthresh > pipe) {
9383 			rack->r_ctl.rc_prr_sndcnt = min((tp->snd_ssthresh - pipe), limit);
9384 			rack_log_to_prr(rack, 11, 0, __LINE__);
9385 		} else {
9386 			rack->r_ctl.rc_prr_sndcnt = min(0, limit);
9387 			rack_log_to_prr(rack, 12, 0, __LINE__);
9388 		}
9389 	}
9390 }
9391 
9392 static void
9393 rack_log_ack(struct tcpcb *tp, struct tcpopt *to, struct tcphdr *th, int entered_recovery, int dup_ack_struck)
9394 {
9395 	uint32_t changed;
9396 	struct tcp_rack *rack;
9397 	struct rack_sendmap *rsm;
9398 	struct sackblk sack, sack_blocks[TCP_MAX_SACK + 1];
9399 	register uint32_t th_ack;
9400 	int32_t i, j, k, num_sack_blks = 0;
9401 	uint32_t cts, acked, ack_point;
9402 	int loop_start = 0, moved_two = 0;
9403 	uint32_t tsused;
9404 
9405 
9406 	INP_WLOCK_ASSERT(tptoinpcb(tp));
9407 	if (tcp_get_flags(th) & TH_RST) {
9408 		/* We don't log resets */
9409 		return;
9410 	}
9411 	rack = (struct tcp_rack *)tp->t_fb_ptr;
9412 	cts = tcp_get_usecs(NULL);
9413 	rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
9414 	changed = 0;
9415 	th_ack = th->th_ack;
9416 	if (rack->sack_attack_disable == 0)
9417 		rack_do_decay(rack);
9418 	if (BYTES_THIS_ACK(tp, th) >= ctf_fixed_maxseg(rack->rc_tp)) {
9419 		/*
9420 		 * You only get credit for
9421 		 * MSS and greater (and you get extra
9422 		 * credit for larger cum-ack moves).
9423 		 */
9424 		int ac;
9425 
9426 		ac = BYTES_THIS_ACK(tp, th) / ctf_fixed_maxseg(rack->rc_tp);
9427 		rack->r_ctl.ack_count += ac;
9428 		counter_u64_add(rack_ack_total, ac);
9429 	}
9430 	if (rack->r_ctl.ack_count > 0xfff00000) {
9431 		/*
9432 		 * reduce the number to keep us under
9433 		 * a uint32_t.
9434 		 */
9435 		rack->r_ctl.ack_count /= 2;
9436 		rack->r_ctl.sack_count /= 2;
9437 	}
9438 	if (SEQ_GT(th_ack, tp->snd_una)) {
9439 		rack_log_progress_event(rack, tp, ticks, PROGRESS_UPDATE, __LINE__);
9440 		tp->t_acktime = ticks;
9441 	}
9442 	if (rsm && SEQ_GT(th_ack, rsm->r_start))
9443 		changed = th_ack - rsm->r_start;
9444 	if (changed) {
9445 		rack_process_to_cumack(tp, rack, th_ack, cts, to);
9446 	}
9447 	if ((to->to_flags & TOF_SACK) == 0) {
9448 		/* We are done nothing left and no sack. */
9449 		rack_handle_might_revert(tp, rack);
9450 		/*
9451 		 * For cases where we struck a dup-ack
9452 		 * with no SACK, add to the changes so
9453 		 * PRR will work right.
9454 		 */
9455 		if (dup_ack_struck && (changed == 0)) {
9456 			changed += ctf_fixed_maxseg(rack->rc_tp);
9457 		}
9458 		goto out;
9459 	}
9460 	/* Sack block processing */
9461 	if (SEQ_GT(th_ack, tp->snd_una))
9462 		ack_point = th_ack;
9463 	else
9464 		ack_point = tp->snd_una;
9465 	for (i = 0; i < to->to_nsacks; i++) {
9466 		bcopy((to->to_sacks + i * TCPOLEN_SACK),
9467 		      &sack, sizeof(sack));
9468 		sack.start = ntohl(sack.start);
9469 		sack.end = ntohl(sack.end);
9470 		if (SEQ_GT(sack.end, sack.start) &&
9471 		    SEQ_GT(sack.start, ack_point) &&
9472 		    SEQ_LT(sack.start, tp->snd_max) &&
9473 		    SEQ_GT(sack.end, ack_point) &&
9474 		    SEQ_LEQ(sack.end, tp->snd_max)) {
9475 			sack_blocks[num_sack_blks] = sack;
9476 			num_sack_blks++;
9477 		} else if (SEQ_LEQ(sack.start, th_ack) &&
9478 			   SEQ_LEQ(sack.end, th_ack)) {
9479 			int was_tlp;
9480 
9481 			was_tlp = rack_note_dsack(rack, sack.start, sack.end);
9482 			/*
9483 			 * Its a D-SACK block.
9484 			 */
9485 			tcp_record_dsack(tp, sack.start, sack.end, was_tlp);
9486 		}
9487 	}
9488 	if (rack->rc_dsack_round_seen) {
9489 		/* Is the dsack roound over? */
9490 		if (SEQ_GEQ(th_ack, rack->r_ctl.dsack_round_end)) {
9491 			/* Yes it is */
9492 			rack->rc_dsack_round_seen = 0;
9493 			rack_log_dsack_event(rack, 3, __LINE__, 0, 0);
9494 		}
9495 	}
9496 	/*
9497 	 * Sort the SACK blocks so we can update the rack scoreboard with
9498 	 * just one pass.
9499 	 */
9500 	num_sack_blks = sack_filter_blks(&rack->r_ctl.rack_sf, sack_blocks,
9501 					 num_sack_blks, th->th_ack);
9502 	ctf_log_sack_filter(rack->rc_tp, num_sack_blks, sack_blocks);
9503 	if (num_sack_blks == 0) {
9504 		/* Nothing to sack (DSACKs?) */
9505 		goto out_with_totals;
9506 	}
9507 	if (num_sack_blks < 2) {
9508 		/* Only one, we don't need to sort */
9509 		goto do_sack_work;
9510 	}
9511 	/* Sort the sacks */
9512 	for (i = 0; i < num_sack_blks; i++) {
9513 		for (j = i + 1; j < num_sack_blks; j++) {
9514 			if (SEQ_GT(sack_blocks[i].end, sack_blocks[j].end)) {
9515 				sack = sack_blocks[i];
9516 				sack_blocks[i] = sack_blocks[j];
9517 				sack_blocks[j] = sack;
9518 			}
9519 		}
9520 	}
9521 	/*
9522 	 * Now are any of the sack block ends the same (yes some
9523 	 * implementations send these)?
9524 	 */
9525 again:
9526 	if (num_sack_blks == 0)
9527 		goto out_with_totals;
9528 	if (num_sack_blks > 1) {
9529 		for (i = 0; i < num_sack_blks; i++) {
9530 			for (j = i + 1; j < num_sack_blks; j++) {
9531 				if (sack_blocks[i].end == sack_blocks[j].end) {
9532 					/*
9533 					 * Ok these two have the same end we
9534 					 * want the smallest end and then
9535 					 * throw away the larger and start
9536 					 * again.
9537 					 */
9538 					if (SEQ_LT(sack_blocks[j].start, sack_blocks[i].start)) {
9539 						/*
9540 						 * The second block covers
9541 						 * more area use that
9542 						 */
9543 						sack_blocks[i].start = sack_blocks[j].start;
9544 					}
9545 					/*
9546 					 * Now collapse out the dup-sack and
9547 					 * lower the count
9548 					 */
9549 					for (k = (j + 1); k < num_sack_blks; k++) {
9550 						sack_blocks[j].start = sack_blocks[k].start;
9551 						sack_blocks[j].end = sack_blocks[k].end;
9552 						j++;
9553 					}
9554 					num_sack_blks--;
9555 					goto again;
9556 				}
9557 			}
9558 		}
9559 	}
9560 do_sack_work:
9561 	/*
9562 	 * First lets look to see if
9563 	 * we have retransmitted and
9564 	 * can use the transmit next?
9565 	 */
9566 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
9567 	if (rsm &&
9568 	    SEQ_GT(sack_blocks[0].end, rsm->r_start) &&
9569 	    SEQ_LT(sack_blocks[0].start, rsm->r_end)) {
9570 		/*
9571 		 * We probably did the FR and the next
9572 		 * SACK in continues as we would expect.
9573 		 */
9574 		acked = rack_proc_sack_blk(tp, rack, &sack_blocks[0], to, &rsm, cts, &moved_two);
9575 		if (acked) {
9576 			rack->r_wanted_output = 1;
9577 			changed += acked;
9578 		}
9579 		if (num_sack_blks == 1) {
9580 			/*
9581 			 * This is what we would expect from
9582 			 * a normal implementation to happen
9583 			 * after we have retransmitted the FR,
9584 			 * i.e the sack-filter pushes down
9585 			 * to 1 block and the next to be retransmitted
9586 			 * is the sequence in the sack block (has more
9587 			 * are acked). Count this as ACK'd data to boost
9588 			 * up the chances of recovering any false positives.
9589 			 */
9590 			rack->r_ctl.ack_count += (acked / ctf_fixed_maxseg(rack->rc_tp));
9591 			counter_u64_add(rack_ack_total, (acked / ctf_fixed_maxseg(rack->rc_tp)));
9592 			counter_u64_add(rack_express_sack, 1);
9593 			if (rack->r_ctl.ack_count > 0xfff00000) {
9594 				/*
9595 				 * reduce the number to keep us under
9596 				 * a uint32_t.
9597 				 */
9598 				rack->r_ctl.ack_count /= 2;
9599 				rack->r_ctl.sack_count /= 2;
9600 			}
9601 			goto out_with_totals;
9602 		} else {
9603 			/*
9604 			 * Start the loop through the
9605 			 * rest of blocks, past the first block.
9606 			 */
9607 			moved_two = 0;
9608 			loop_start = 1;
9609 		}
9610 	}
9611 	/* Its a sack of some sort */
9612 	rack->r_ctl.sack_count++;
9613 	if (rack->r_ctl.sack_count > 0xfff00000) {
9614 		/*
9615 		 * reduce the number to keep us under
9616 		 * a uint32_t.
9617 		 */
9618 		rack->r_ctl.ack_count /= 2;
9619 		rack->r_ctl.sack_count /= 2;
9620 	}
9621 	counter_u64_add(rack_sack_total, 1);
9622 	if (rack->sack_attack_disable) {
9623 		/* An attacker disablement is in place */
9624 		if (num_sack_blks > 1) {
9625 			rack->r_ctl.sack_count += (num_sack_blks - 1);
9626 			rack->r_ctl.sack_moved_extra++;
9627 			counter_u64_add(rack_move_some, 1);
9628 			if (rack->r_ctl.sack_moved_extra > 0xfff00000) {
9629 				rack->r_ctl.sack_moved_extra /= 2;
9630 				rack->r_ctl.sack_noextra_move /= 2;
9631 			}
9632 		}
9633 		goto out;
9634 	}
9635 	rsm = rack->r_ctl.rc_sacklast;
9636 	for (i = loop_start; i < num_sack_blks; i++) {
9637 		acked = rack_proc_sack_blk(tp, rack, &sack_blocks[i], to, &rsm, cts, &moved_two);
9638 		if (acked) {
9639 			rack->r_wanted_output = 1;
9640 			changed += acked;
9641 		}
9642 		if (moved_two) {
9643 			/*
9644 			 * If we did not get a SACK for at least a MSS and
9645 			 * had to move at all, or if we moved more than our
9646 			 * threshold, it counts against the "extra" move.
9647 			 */
9648 			rack->r_ctl.sack_moved_extra += moved_two;
9649 			counter_u64_add(rack_move_some, 1);
9650 		} else {
9651 			/*
9652 			 * else we did not have to move
9653 			 * any more than we would expect.
9654 			 */
9655 			rack->r_ctl.sack_noextra_move++;
9656 			counter_u64_add(rack_move_none, 1);
9657 		}
9658 		if (moved_two && (acked < ctf_fixed_maxseg(rack->rc_tp))) {
9659 			/*
9660 			 * If the SACK was not a full MSS then
9661 			 * we add to sack_count the number of
9662 			 * MSS's (or possibly more than
9663 			 * a MSS if its a TSO send) we had to skip by.
9664 			 */
9665 			rack->r_ctl.sack_count += moved_two;
9666 			counter_u64_add(rack_sack_total, moved_two);
9667 		}
9668 		/*
9669 		 * Now we need to setup for the next
9670 		 * round. First we make sure we won't
9671 		 * exceed the size of our uint32_t on
9672 		 * the various counts, and then clear out
9673 		 * moved_two.
9674 		 */
9675 		if ((rack->r_ctl.sack_moved_extra > 0xfff00000) ||
9676 		    (rack->r_ctl.sack_noextra_move > 0xfff00000)) {
9677 			rack->r_ctl.sack_moved_extra /= 2;
9678 			rack->r_ctl.sack_noextra_move /= 2;
9679 		}
9680 		if (rack->r_ctl.sack_count > 0xfff00000) {
9681 			rack->r_ctl.ack_count /= 2;
9682 			rack->r_ctl.sack_count /= 2;
9683 		}
9684 		moved_two = 0;
9685 	}
9686 out_with_totals:
9687 	if (num_sack_blks > 1) {
9688 		/*
9689 		 * You get an extra stroke if
9690 		 * you have more than one sack-blk, this
9691 		 * could be where we are skipping forward
9692 		 * and the sack-filter is still working, or
9693 		 * it could be an attacker constantly
9694 		 * moving us.
9695 		 */
9696 		rack->r_ctl.sack_moved_extra++;
9697 		counter_u64_add(rack_move_some, 1);
9698 	}
9699 out:
9700 #ifdef NETFLIX_EXP_DETECTION
9701 	rack_do_detection(tp, rack, BYTES_THIS_ACK(tp, th), ctf_fixed_maxseg(rack->rc_tp));
9702 #endif
9703 	if (changed) {
9704 		/* Something changed cancel the rack timer */
9705 		rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
9706 	}
9707 	tsused = tcp_get_usecs(NULL);
9708 	rsm = tcp_rack_output(tp, rack, tsused);
9709 	if ((!IN_FASTRECOVERY(tp->t_flags)) &&
9710 	    rsm &&
9711 	    ((rsm->r_flags & RACK_MUST_RXT) == 0)) {
9712 		/* Enter recovery */
9713 		entered_recovery = 1;
9714 		rack_cong_signal(tp, CC_NDUPACK, tp->snd_una, __LINE__);
9715 		/*
9716 		 * When we enter recovery we need to assure we send
9717 		 * one packet.
9718 		 */
9719 		if (rack->rack_no_prr == 0) {
9720 			rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
9721 			rack_log_to_prr(rack, 8, 0, __LINE__);
9722 		}
9723 		rack->r_timer_override = 1;
9724 		rack->r_early = 0;
9725 		rack->r_ctl.rc_agg_early = 0;
9726 	} else if (IN_FASTRECOVERY(tp->t_flags) &&
9727 		   rsm &&
9728 		   (rack->r_rr_config == 3)) {
9729 		/*
9730 		 * Assure we can output and we get no
9731 		 * remembered pace time except the retransmit.
9732 		 */
9733 		rack->r_timer_override = 1;
9734 		rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
9735 		rack->r_ctl.rc_resend = rsm;
9736 	}
9737 	if (IN_FASTRECOVERY(tp->t_flags) &&
9738 	    (rack->rack_no_prr == 0) &&
9739 	    (entered_recovery == 0)) {
9740 		rack_update_prr(tp, rack, changed, th_ack);
9741 		if ((rsm && (rack->r_ctl.rc_prr_sndcnt >= ctf_fixed_maxseg(tp)) &&
9742 		     ((tcp_in_hpts(rack->rc_inp) == 0) &&
9743 		      ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0)))) {
9744 			/*
9745 			 * If you are pacing output you don't want
9746 			 * to override.
9747 			 */
9748 			rack->r_early = 0;
9749 			rack->r_ctl.rc_agg_early = 0;
9750 			rack->r_timer_override = 1;
9751 		}
9752 	}
9753 }
9754 
9755 static void
9756 rack_strike_dupack(struct tcp_rack *rack)
9757 {
9758 	struct rack_sendmap *rsm;
9759 
9760 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
9761 	while (rsm && (rsm->r_dupack >= DUP_ACK_THRESHOLD)) {
9762 		rsm = TAILQ_NEXT(rsm, r_tnext);
9763 		if (rsm->r_flags & RACK_MUST_RXT) {
9764 			/* Sendmap entries that are marked to
9765 			 * be retransmitted do not need dupack's
9766 			 * struck. We get these marks for a number
9767 			 * of reasons (rxt timeout with no sack,
9768 			 * mtu change, or rwnd collapses). When
9769 			 * these events occur, we know we must retransmit
9770 			 * them and mark the sendmap entries. Dupack counting
9771 			 * is not needed since we are already set to retransmit
9772 			 * it as soon as we can.
9773 			 */
9774 			continue;
9775 		}
9776 	}
9777 	if (rsm && (rsm->r_dupack < 0xff)) {
9778 		rsm->r_dupack++;
9779 		if (rsm->r_dupack >= DUP_ACK_THRESHOLD) {
9780 			struct timeval tv;
9781 			uint32_t cts;
9782 			/*
9783 			 * Here we see if we need to retransmit. For
9784 			 * a SACK type connection if enough time has passed
9785 			 * we will get a return of the rsm. For a non-sack
9786 			 * connection we will get the rsm returned if the
9787 			 * dupack value is 3 or more.
9788 			 */
9789 			cts = tcp_get_usecs(&tv);
9790 			rack->r_ctl.rc_resend = tcp_rack_output(rack->rc_tp, rack, cts);
9791 			if (rack->r_ctl.rc_resend != NULL) {
9792 				if (!IN_FASTRECOVERY(rack->rc_tp->t_flags)) {
9793 					rack_cong_signal(rack->rc_tp, CC_NDUPACK,
9794 							 rack->rc_tp->snd_una, __LINE__);
9795 				}
9796 				rack->r_wanted_output = 1;
9797 				rack->r_timer_override = 1;
9798 				rack_log_retran_reason(rack, rsm, __LINE__, 1, 3);
9799 			}
9800 		} else {
9801 			rack_log_retran_reason(rack, rsm, __LINE__, 0, 3);
9802 		}
9803 	}
9804 }
9805 
9806 static void
9807 rack_check_bottom_drag(struct tcpcb *tp,
9808 		       struct tcp_rack *rack,
9809 		       struct socket *so, int32_t acked)
9810 {
9811 	uint32_t segsiz, minseg;
9812 
9813 	segsiz = ctf_fixed_maxseg(tp);
9814 	minseg = segsiz;
9815 
9816 	if (tp->snd_max == tp->snd_una) {
9817 		/*
9818 		 * We are doing dynamic pacing and we are way
9819 		 * under. Basically everything got acked while
9820 		 * we were still waiting on the pacer to expire.
9821 		 *
9822 		 * This means we need to boost the b/w in
9823 		 * addition to any earlier boosting of
9824 		 * the multiplier.
9825 		 */
9826 		rack->rc_dragged_bottom = 1;
9827 		rack_validate_multipliers_at_or_above100(rack);
9828 		/*
9829 		 * Lets use the segment bytes acked plus
9830 		 * the lowest RTT seen as the basis to
9831 		 * form a b/w estimate. This will be off
9832 		 * due to the fact that the true estimate
9833 		 * should be around 1/2 the time of the RTT
9834 		 * but we can settle for that.
9835 		 */
9836 		if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_VALID) &&
9837 		    acked) {
9838 			uint64_t bw, calc_bw, rtt;
9839 
9840 			rtt = rack->r_ctl.rack_rs.rs_us_rtt;
9841 			if (rtt == 0) {
9842 				/* no us sample is there a ms one? */
9843 				if (rack->r_ctl.rack_rs.rs_rtt_lowest) {
9844 					rtt = rack->r_ctl.rack_rs.rs_rtt_lowest;
9845 				} else {
9846 					goto no_measurement;
9847 				}
9848 			}
9849 			bw = acked;
9850 			calc_bw = bw * 1000000;
9851 			calc_bw /= rtt;
9852 			if (rack->r_ctl.last_max_bw &&
9853 			    (rack->r_ctl.last_max_bw < calc_bw)) {
9854 				/*
9855 				 * If we have a last calculated max bw
9856 				 * enforce it.
9857 				 */
9858 				calc_bw = rack->r_ctl.last_max_bw;
9859 			}
9860 			/* now plop it in */
9861 			if (rack->rc_gp_filled == 0) {
9862 				if (calc_bw > ONE_POINT_TWO_MEG) {
9863 					/*
9864 					 * If we have no measurement
9865 					 * don't let us set in more than
9866 					 * 1.2Mbps. If we are still too
9867 					 * low after pacing with this we
9868 					 * will hopefully have a max b/w
9869 					 * available to sanity check things.
9870 					 */
9871 					calc_bw = ONE_POINT_TWO_MEG;
9872 				}
9873 				rack->r_ctl.rc_rtt_diff = 0;
9874 				rack->r_ctl.gp_bw = calc_bw;
9875 				rack->rc_gp_filled = 1;
9876 				if (rack->r_ctl.num_measurements < RACK_REQ_AVG)
9877 					rack->r_ctl.num_measurements = RACK_REQ_AVG;
9878 				rack_set_pace_segments(rack->rc_tp, rack, __LINE__, NULL);
9879 			} else if (calc_bw > rack->r_ctl.gp_bw) {
9880 				rack->r_ctl.rc_rtt_diff = 0;
9881 				if (rack->r_ctl.num_measurements < RACK_REQ_AVG)
9882 					rack->r_ctl.num_measurements = RACK_REQ_AVG;
9883 				rack->r_ctl.gp_bw = calc_bw;
9884 				rack_set_pace_segments(rack->rc_tp, rack, __LINE__, NULL);
9885 			} else
9886 				rack_increase_bw_mul(rack, -1, 0, 0, 1);
9887 			if ((rack->gp_ready == 0) &&
9888 			    (rack->r_ctl.num_measurements >= rack->r_ctl.req_measurements)) {
9889 				/* We have enough measurements now */
9890 				rack->gp_ready = 1;
9891 				rack_set_cc_pacing(rack);
9892 				if (rack->defer_options)
9893 					rack_apply_deferred_options(rack);
9894 			}
9895 			/*
9896 			 * For acks over 1mss we do a extra boost to simulate
9897 			 * where we would get 2 acks (we want 110 for the mul).
9898 			 */
9899 			if (acked > segsiz)
9900 				rack_increase_bw_mul(rack, -1, 0, 0, 1);
9901 		} else {
9902 			/*
9903 			 * zero rtt possibly?, settle for just an old increase.
9904 			 */
9905 no_measurement:
9906 			rack_increase_bw_mul(rack, -1, 0, 0, 1);
9907 		}
9908 	} else if ((IN_FASTRECOVERY(tp->t_flags) == 0) &&
9909 		   (sbavail(&so->so_snd) > max((segsiz * (4 + rack_req_segs)),
9910 					       minseg)) &&
9911 		   (rack->r_ctl.cwnd_to_use > max((segsiz * (rack_req_segs + 2)), minseg)) &&
9912 		   (tp->snd_wnd > max((segsiz * (rack_req_segs + 2)), minseg)) &&
9913 		   (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) <=
9914 		    (segsiz * rack_req_segs))) {
9915 		/*
9916 		 * We are doing dynamic GP pacing and
9917 		 * we have everything except 1MSS or less
9918 		 * bytes left out. We are still pacing away.
9919 		 * And there is data that could be sent, This
9920 		 * means we are inserting delayed ack time in
9921 		 * our measurements because we are pacing too slow.
9922 		 */
9923 		rack_validate_multipliers_at_or_above100(rack);
9924 		rack->rc_dragged_bottom = 1;
9925 		rack_increase_bw_mul(rack, -1, 0, 0, 1);
9926 	}
9927 }
9928 
9929 
9930 
9931 static void
9932 rack_gain_for_fastoutput(struct tcp_rack *rack, struct tcpcb *tp, struct socket *so, uint32_t acked_amount)
9933 {
9934 	/*
9935 	 * The fast output path is enabled and we
9936 	 * have moved the cumack forward. Lets see if
9937 	 * we can expand forward the fast path length by
9938 	 * that amount. What we would ideally like to
9939 	 * do is increase the number of bytes in the
9940 	 * fast path block (left_to_send) by the
9941 	 * acked amount. However we have to gate that
9942 	 * by two factors:
9943 	 * 1) The amount outstanding and the rwnd of the peer
9944 	 *    (i.e. we don't want to exceed the rwnd of the peer).
9945 	 *    <and>
9946 	 * 2) The amount of data left in the socket buffer (i.e.
9947 	 *    we can't send beyond what is in the buffer).
9948 	 *
9949 	 * Note that this does not take into account any increase
9950 	 * in the cwnd. We will only extend the fast path by
9951 	 * what was acked.
9952 	 */
9953 	uint32_t new_total, gating_val;
9954 
9955 	new_total = acked_amount + rack->r_ctl.fsb.left_to_send;
9956 	gating_val = min((sbavail(&so->so_snd) - (tp->snd_max - tp->snd_una)),
9957 			 (tp->snd_wnd - (tp->snd_max - tp->snd_una)));
9958 	if (new_total <= gating_val) {
9959 		/* We can increase left_to_send by the acked amount */
9960 		counter_u64_add(rack_extended_rfo, 1);
9961 		rack->r_ctl.fsb.left_to_send = new_total;
9962 		KASSERT((rack->r_ctl.fsb.left_to_send <= (sbavail(&rack->rc_inp->inp_socket->so_snd) - (tp->snd_max - tp->snd_una))),
9963 			("rack:%p left_to_send:%u sbavail:%u out:%u",
9964 			 rack, rack->r_ctl.fsb.left_to_send,
9965 			 sbavail(&rack->rc_inp->inp_socket->so_snd),
9966 			 (tp->snd_max - tp->snd_una)));
9967 
9968 	}
9969 }
9970 
9971 static void
9972 rack_adjust_sendmap(struct tcp_rack *rack, struct sockbuf *sb, tcp_seq snd_una)
9973 {
9974 	/*
9975 	 * Here any sendmap entry that points to the
9976 	 * beginning mbuf must be adjusted to the correct
9977 	 * offset. This must be called with:
9978 	 * 1) The socket buffer locked
9979 	 * 2) snd_una adjusted to its new position.
9980 	 *
9981 	 * Note that (2) implies rack_ack_received has also
9982 	 * been called.
9983 	 *
9984 	 * We grab the first mbuf in the socket buffer and
9985 	 * then go through the front of the sendmap, recalculating
9986 	 * the stored offset for any sendmap entry that has
9987 	 * that mbuf. We must use the sb functions to do this
9988 	 * since its possible an add was done has well as
9989 	 * the subtraction we may have just completed. This should
9990 	 * not be a penalty though, since we just referenced the sb
9991 	 * to go in and trim off the mbufs that we freed (of course
9992 	 * there will be a penalty for the sendmap references though).
9993 	 */
9994 	struct mbuf *m;
9995 	struct rack_sendmap *rsm;
9996 
9997 	SOCKBUF_LOCK_ASSERT(sb);
9998 	m = sb->sb_mb;
9999 	rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
10000 	if ((rsm == NULL) || (m == NULL)) {
10001 		/* Nothing outstanding */
10002 		return;
10003 	}
10004 	while (rsm->m && (rsm->m == m)) {
10005 		/* one to adjust */
10006 #ifdef INVARIANTS
10007 		struct mbuf *tm;
10008 		uint32_t soff;
10009 
10010 		tm = sbsndmbuf(sb, (rsm->r_start - snd_una), &soff);
10011 		if (rsm->orig_m_len != m->m_len) {
10012 			rack_adjust_orig_mlen(rsm);
10013 		}
10014 		if (rsm->soff != soff) {
10015 			/*
10016 			 * This is not a fatal error, we anticipate it
10017 			 * might happen (the else code), so we count it here
10018 			 * so that under invariant we can see that it really
10019 			 * does happen.
10020 			 */
10021 			counter_u64_add(rack_adjust_map_bw, 1);
10022 		}
10023 		rsm->m = tm;
10024 		rsm->soff = soff;
10025 		if (tm)
10026 			rsm->orig_m_len = rsm->m->m_len;
10027 		else
10028 			rsm->orig_m_len = 0;
10029 #else
10030 		rsm->m = sbsndmbuf(sb, (rsm->r_start - snd_una), &rsm->soff);
10031 		if (rsm->m)
10032 			rsm->orig_m_len = rsm->m->m_len;
10033 		else
10034 			rsm->orig_m_len = 0;
10035 #endif
10036 		rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree,
10037 			      rsm);
10038 		if (rsm == NULL)
10039 			break;
10040 	}
10041 }
10042 
10043 /*
10044  * Return value of 1, we do not need to call rack_process_data().
10045  * return value of 0, rack_process_data can be called.
10046  * For ret_val if its 0 the TCP is locked, if its non-zero
10047  * its unlocked and probably unsafe to touch the TCB.
10048  */
10049 static int
10050 rack_process_ack(struct mbuf *m, struct tcphdr *th, struct socket *so,
10051     struct tcpcb *tp, struct tcpopt *to,
10052     uint32_t tiwin, int32_t tlen,
10053     int32_t * ofia, int32_t thflags, int32_t *ret_val)
10054 {
10055 	int32_t ourfinisacked = 0;
10056 	int32_t nsegs, acked_amount;
10057 	int32_t acked;
10058 	struct mbuf *mfree;
10059 	struct tcp_rack *rack;
10060 	int32_t under_pacing = 0;
10061 	int32_t recovery = 0;
10062 
10063 	INP_WLOCK_ASSERT(tptoinpcb(tp));
10064 
10065 	rack = (struct tcp_rack *)tp->t_fb_ptr;
10066 	if (SEQ_GT(th->th_ack, tp->snd_max)) {
10067 		__ctf_do_dropafterack(m, tp, th, thflags, tlen, ret_val,
10068 				      &rack->r_ctl.challenge_ack_ts,
10069 				      &rack->r_ctl.challenge_ack_cnt);
10070 		rack->r_wanted_output = 1;
10071 		return (1);
10072 	}
10073 	if (rack->gp_ready &&
10074 	    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
10075 		under_pacing = 1;
10076 	}
10077 	if (SEQ_GEQ(th->th_ack, tp->snd_una) || to->to_nsacks) {
10078 		int in_rec, dup_ack_struck = 0;
10079 
10080 		in_rec = IN_FASTRECOVERY(tp->t_flags);
10081 		if (rack->rc_in_persist) {
10082 			tp->t_rxtshift = 0;
10083 			RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
10084 				      rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
10085 		}
10086 		if ((th->th_ack == tp->snd_una) &&
10087 		    (tiwin == tp->snd_wnd) &&
10088 		    ((to->to_flags & TOF_SACK) == 0)) {
10089 			rack_strike_dupack(rack);
10090 			dup_ack_struck = 1;
10091 		}
10092 		rack_log_ack(tp, to, th, ((in_rec == 0) && IN_FASTRECOVERY(tp->t_flags)), dup_ack_struck);
10093 	}
10094 	if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
10095 		/*
10096 		 * Old ack, behind (or duplicate to) the last one rcv'd
10097 		 * Note: We mark reordering is occuring if its
10098 		 * less than and we have not closed our window.
10099 		 */
10100 		if (SEQ_LT(th->th_ack, tp->snd_una) && (sbspace(&so->so_rcv) > ctf_fixed_maxseg(tp))) {
10101 			rack->r_ctl.rc_reorder_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
10102 		}
10103 		return (0);
10104 	}
10105 	/*
10106 	 * If we reach this point, ACK is not a duplicate, i.e., it ACKs
10107 	 * something we sent.
10108 	 */
10109 	if (tp->t_flags & TF_NEEDSYN) {
10110 		/*
10111 		 * T/TCP: Connection was half-synchronized, and our SYN has
10112 		 * been ACK'd (so connection is now fully synchronized).  Go
10113 		 * to non-starred state, increment snd_una for ACK of SYN,
10114 		 * and check if we can do window scaling.
10115 		 */
10116 		tp->t_flags &= ~TF_NEEDSYN;
10117 		tp->snd_una++;
10118 		/* Do window scaling? */
10119 		if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
10120 		    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
10121 			tp->rcv_scale = tp->request_r_scale;
10122 			/* Send window already scaled. */
10123 		}
10124 	}
10125 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
10126 
10127 	acked = BYTES_THIS_ACK(tp, th);
10128 	if (acked) {
10129 		/*
10130 		 * Any time we move the cum-ack forward clear
10131 		 * keep-alive tied probe-not-answered. The
10132 		 * persists clears its own on entry.
10133 		 */
10134 		rack->probe_not_answered = 0;
10135 	}
10136 	KMOD_TCPSTAT_ADD(tcps_rcvackpack, nsegs);
10137 	KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
10138 	/*
10139 	 * If we just performed our first retransmit, and the ACK arrives
10140 	 * within our recovery window, then it was a mistake to do the
10141 	 * retransmit in the first place.  Recover our original cwnd and
10142 	 * ssthresh, and proceed to transmit where we left off.
10143 	 */
10144 	if ((tp->t_flags & TF_PREVVALID) &&
10145 	    ((tp->t_flags & TF_RCVD_TSTMP) == 0)) {
10146 		tp->t_flags &= ~TF_PREVVALID;
10147 		if (tp->t_rxtshift == 1 &&
10148 		    (int)(ticks - tp->t_badrxtwin) < 0)
10149 			rack_cong_signal(tp, CC_RTO_ERR, th->th_ack, __LINE__);
10150 	}
10151 	if (acked) {
10152 		/* assure we are not backed off */
10153 		tp->t_rxtshift = 0;
10154 		RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
10155 			      rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
10156 		rack->rc_tlp_in_progress = 0;
10157 		rack->r_ctl.rc_tlp_cnt_out = 0;
10158 		/*
10159 		 * If it is the RXT timer we want to
10160 		 * stop it, so we can restart a TLP.
10161 		 */
10162 		if (rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT)
10163 			rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
10164 #ifdef NETFLIX_HTTP_LOGGING
10165 		tcp_http_check_for_comp(rack->rc_tp, th->th_ack);
10166 #endif
10167 	}
10168 	/*
10169 	 * If we have a timestamp reply, update smoothed round trip time. If
10170 	 * no timestamp is present but transmit timer is running and timed
10171 	 * sequence number was acked, update smoothed round trip time. Since
10172 	 * we now have an rtt measurement, cancel the timer backoff (cf.,
10173 	 * Phil Karn's retransmit alg.). Recompute the initial retransmit
10174 	 * timer.
10175 	 *
10176 	 * Some boxes send broken timestamp replies during the SYN+ACK
10177 	 * phase, ignore timestamps of 0 or we could calculate a huge RTT
10178 	 * and blow up the retransmit timer.
10179 	 */
10180 	/*
10181 	 * If all outstanding data is acked, stop retransmit timer and
10182 	 * remember to restart (more output or persist). If there is more
10183 	 * data to be acked, restart retransmit timer, using current
10184 	 * (possibly backed-off) value.
10185 	 */
10186 	if (acked == 0) {
10187 		if (ofia)
10188 			*ofia = ourfinisacked;
10189 		return (0);
10190 	}
10191 	if (IN_RECOVERY(tp->t_flags)) {
10192 		if (SEQ_LT(th->th_ack, tp->snd_recover) &&
10193 		    (SEQ_LT(th->th_ack, tp->snd_max))) {
10194 			tcp_rack_partialack(tp);
10195 		} else {
10196 			rack_post_recovery(tp, th->th_ack);
10197 			recovery = 1;
10198 		}
10199 	}
10200 	/*
10201 	 * Let the congestion control algorithm update congestion control
10202 	 * related information. This typically means increasing the
10203 	 * congestion window.
10204 	 */
10205 	rack_ack_received(tp, rack, th->th_ack, nsegs, CC_ACK, recovery);
10206 	SOCKBUF_LOCK(&so->so_snd);
10207 	acked_amount = min(acked, (int)sbavail(&so->so_snd));
10208 	tp->snd_wnd -= acked_amount;
10209 	mfree = sbcut_locked(&so->so_snd, acked_amount);
10210 	if ((sbused(&so->so_snd) == 0) &&
10211 	    (acked > acked_amount) &&
10212 	    (tp->t_state >= TCPS_FIN_WAIT_1) &&
10213 	    (tp->t_flags & TF_SENTFIN)) {
10214 		/*
10215 		 * We must be sure our fin
10216 		 * was sent and acked (we can be
10217 		 * in FIN_WAIT_1 without having
10218 		 * sent the fin).
10219 		 */
10220 		ourfinisacked = 1;
10221 	}
10222 	tp->snd_una = th->th_ack;
10223 	if (acked_amount && sbavail(&so->so_snd))
10224 		rack_adjust_sendmap(rack, &so->so_snd, tp->snd_una);
10225 	rack_log_wakeup(tp,rack, &so->so_snd, acked, 2);
10226 	/* NB: sowwakeup_locked() does an implicit unlock. */
10227 	sowwakeup_locked(so);
10228 	m_freem(mfree);
10229 	if (SEQ_GT(tp->snd_una, tp->snd_recover))
10230 		tp->snd_recover = tp->snd_una;
10231 
10232 	if (SEQ_LT(tp->snd_nxt, tp->snd_una)) {
10233 		tp->snd_nxt = tp->snd_una;
10234 	}
10235 	if (under_pacing &&
10236 	    (rack->use_fixed_rate == 0) &&
10237 	    (rack->in_probe_rtt == 0) &&
10238 	    rack->rc_gp_dyn_mul &&
10239 	    rack->rc_always_pace) {
10240 		/* Check if we are dragging bottom */
10241 		rack_check_bottom_drag(tp, rack, so, acked);
10242 	}
10243 	if (tp->snd_una == tp->snd_max) {
10244 		/* Nothing left outstanding */
10245 		tp->t_flags &= ~TF_PREVVALID;
10246 		rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
10247 		rack->r_ctl.retran_during_recovery = 0;
10248 		rack->r_ctl.dsack_byte_cnt = 0;
10249 		if (rack->r_ctl.rc_went_idle_time == 0)
10250 			rack->r_ctl.rc_went_idle_time = 1;
10251 		rack_log_progress_event(rack, tp, 0, PROGRESS_CLEAR, __LINE__);
10252 		if (sbavail(&tptosocket(tp)->so_snd) == 0)
10253 			tp->t_acktime = 0;
10254 		rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
10255 		/* Set need output so persist might get set */
10256 		rack->r_wanted_output = 1;
10257 		sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
10258 		if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
10259 		    (sbavail(&so->so_snd) == 0) &&
10260 		    (tp->t_flags2 & TF2_DROP_AF_DATA)) {
10261 			/*
10262 			 * The socket was gone and the
10263 			 * peer sent data (now or in the past), time to
10264 			 * reset him.
10265 			 */
10266 			*ret_val = 1;
10267 			/* tcp_close will kill the inp pre-log the Reset */
10268 			tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
10269 			tp = tcp_close(tp);
10270 			ctf_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, tlen);
10271 			return (1);
10272 		}
10273 	}
10274 	if (ofia)
10275 		*ofia = ourfinisacked;
10276 	return (0);
10277 }
10278 
10279 
10280 static void
10281 rack_log_collapse(struct tcp_rack *rack, uint32_t cnt, uint32_t split, uint32_t out, int line,
10282 		  int dir, uint32_t flags, struct rack_sendmap *rsm)
10283 {
10284 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
10285 		union tcp_log_stackspecific log;
10286 		struct timeval tv;
10287 
10288 		memset(&log, 0, sizeof(log));
10289 		log.u_bbr.flex1 = cnt;
10290 		log.u_bbr.flex2 = split;
10291 		log.u_bbr.flex3 = out;
10292 		log.u_bbr.flex4 = line;
10293 		log.u_bbr.flex5 = rack->r_must_retran;
10294 		log.u_bbr.flex6 = flags;
10295 		log.u_bbr.flex7 = rack->rc_has_collapsed;
10296 		log.u_bbr.flex8 = dir;	/*
10297 					 * 1 is collapsed, 0 is uncollapsed,
10298 					 * 2 is log of a rsm being marked, 3 is a split.
10299 					 */
10300 		if (rsm == NULL)
10301 			log.u_bbr.rttProp = 0;
10302 		else
10303 			log.u_bbr.rttProp = (uint64_t)rsm;
10304 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
10305 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
10306 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
10307 		    &rack->rc_inp->inp_socket->so_rcv,
10308 		    &rack->rc_inp->inp_socket->so_snd,
10309 		    TCP_RACK_LOG_COLLAPSE, 0,
10310 		    0, &log, false, &tv);
10311 	}
10312 }
10313 
10314 static void
10315 rack_collapsed_window(struct tcp_rack *rack, uint32_t out, int line)
10316 {
10317 	/*
10318 	 * Here all we do is mark the collapsed point and set the flag.
10319 	 * This may happen again and again, but there is no
10320 	 * sense splitting our map until we know where the
10321 	 * peer finally lands in the collapse.
10322 	 */
10323 	rack_trace_point(rack, RACK_TP_COLLAPSED_WND);
10324 	if ((rack->rc_has_collapsed == 0) ||
10325 	    (rack->r_ctl.last_collapse_point != (rack->rc_tp->snd_una + rack->rc_tp->snd_wnd)))
10326 		counter_u64_add(rack_collapsed_win_seen, 1);
10327 	rack->r_ctl.last_collapse_point = rack->rc_tp->snd_una + rack->rc_tp->snd_wnd;
10328 	rack->r_ctl.high_collapse_point = rack->rc_tp->snd_max;
10329 	rack->rc_has_collapsed = 1;
10330 	rack->r_collapse_point_valid = 1;
10331 	rack_log_collapse(rack, 0, 0, rack->r_ctl.last_collapse_point, line, 1, 0, NULL);
10332 }
10333 
10334 static void
10335 rack_un_collapse_window(struct tcp_rack *rack, int line)
10336 {
10337 	struct rack_sendmap *nrsm, *rsm, fe;
10338 	int cnt = 0, split = 0;
10339 #ifdef INVARIANTS
10340 	struct rack_sendmap *insret;
10341 #endif
10342 
10343 	memset(&fe, 0, sizeof(fe));
10344 	rack->rc_has_collapsed = 0;
10345 	fe.r_start = rack->r_ctl.last_collapse_point;
10346 	rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
10347 	if (rsm == NULL) {
10348 		/* Nothing to do maybe the peer ack'ed it all */
10349 		rack_log_collapse(rack, 0, 0, ctf_outstanding(rack->rc_tp), line, 0, 0, NULL);
10350 		return;
10351 	}
10352 	/* Now do we need to split this one? */
10353 	if (SEQ_GT(rack->r_ctl.last_collapse_point, rsm->r_start)) {
10354 		rack_log_collapse(rack, rsm->r_start, rsm->r_end,
10355 				  rack->r_ctl.last_collapse_point, line, 3, rsm->r_flags, rsm);
10356 		nrsm = rack_alloc_limit(rack, RACK_LIMIT_TYPE_SPLIT);
10357 		if (nrsm == NULL) {
10358 			/* We can't get a rsm, mark all? */
10359 			nrsm = rsm;
10360 			goto no_split;
10361 		}
10362 		/* Clone it */
10363 		split = 1;
10364 		rack_clone_rsm(rack, nrsm, rsm, rack->r_ctl.last_collapse_point);
10365 #ifndef INVARIANTS
10366 		(void)RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
10367 #else
10368 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
10369 		if (insret != NULL) {
10370 			panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
10371 			      nrsm, insret, rack, rsm);
10372 		}
10373 #endif
10374 		rack_log_map_chg(rack->rc_tp, rack, NULL, rsm, nrsm, MAP_SPLIT,
10375 				 rack->r_ctl.last_collapse_point, __LINE__);
10376 		if (rsm->r_in_tmap) {
10377 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
10378 			nrsm->r_in_tmap = 1;
10379 		}
10380 		/*
10381 		 * Set in the new RSM as the
10382 		 * collapsed starting point
10383 		 */
10384 		rsm = nrsm;
10385 	}
10386 no_split:
10387 	RB_FOREACH_FROM(nrsm, rack_rb_tree_head, rsm) {
10388 		nrsm->r_flags |= RACK_RWND_COLLAPSED;
10389 		rack_log_collapse(rack, nrsm->r_start, nrsm->r_end, 0, line, 4, nrsm->r_flags, nrsm);
10390 		cnt++;
10391 	}
10392 	if (cnt) {
10393 		counter_u64_add(rack_collapsed_win, 1);
10394 	}
10395 	rack_log_collapse(rack, cnt, split, ctf_outstanding(rack->rc_tp), line, 0, 0, NULL);
10396 }
10397 
10398 static void
10399 rack_handle_delayed_ack(struct tcpcb *tp, struct tcp_rack *rack,
10400 			int32_t tlen, int32_t tfo_syn)
10401 {
10402 	if (DELAY_ACK(tp, tlen) || tfo_syn) {
10403 		if (rack->rc_dack_mode &&
10404 		    (tlen > 500) &&
10405 		    (rack->rc_dack_toggle == 1)) {
10406 			goto no_delayed_ack;
10407 		}
10408 		rack_timer_cancel(tp, rack,
10409 				  rack->r_ctl.rc_rcvtime, __LINE__);
10410 		tp->t_flags |= TF_DELACK;
10411 	} else {
10412 no_delayed_ack:
10413 		rack->r_wanted_output = 1;
10414 		tp->t_flags |= TF_ACKNOW;
10415 		if (rack->rc_dack_mode) {
10416 			if (tp->t_flags & TF_DELACK)
10417 				rack->rc_dack_toggle = 1;
10418 			else
10419 				rack->rc_dack_toggle = 0;
10420 		}
10421 	}
10422 }
10423 
10424 static void
10425 rack_validate_fo_sendwin_up(struct tcpcb *tp, struct tcp_rack *rack)
10426 {
10427 	/*
10428 	 * If fast output is in progress, lets validate that
10429 	 * the new window did not shrink on us and make it
10430 	 * so fast output should end.
10431 	 */
10432 	if (rack->r_fast_output) {
10433 		uint32_t out;
10434 
10435 		/*
10436 		 * Calculate what we will send if left as is
10437 		 * and compare that to our send window.
10438 		 */
10439 		out = ctf_outstanding(tp);
10440 		if ((out + rack->r_ctl.fsb.left_to_send) > tp->snd_wnd) {
10441 			/* ok we have an issue */
10442 			if (out >= tp->snd_wnd) {
10443 				/* Turn off fast output the window is met or collapsed */
10444 				rack->r_fast_output = 0;
10445 			} else {
10446 				/* we have some room left */
10447 				rack->r_ctl.fsb.left_to_send = tp->snd_wnd - out;
10448 				if (rack->r_ctl.fsb.left_to_send < ctf_fixed_maxseg(tp)) {
10449 					/* If not at least 1 full segment never mind */
10450 					rack->r_fast_output = 0;
10451 				}
10452 			}
10453 		}
10454 	}
10455 }
10456 
10457 
10458 /*
10459  * Return value of 1, the TCB is unlocked and most
10460  * likely gone, return value of 0, the TCP is still
10461  * locked.
10462  */
10463 static int
10464 rack_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so,
10465     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
10466     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
10467 {
10468 	/*
10469 	 * Update window information. Don't look at window if no ACK: TAC's
10470 	 * send garbage on first SYN.
10471 	 */
10472 	int32_t nsegs;
10473 	int32_t tfo_syn;
10474 	struct tcp_rack *rack;
10475 
10476 	INP_WLOCK_ASSERT(tptoinpcb(tp));
10477 
10478 	rack = (struct tcp_rack *)tp->t_fb_ptr;
10479 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
10480 	if ((thflags & TH_ACK) &&
10481 	    (SEQ_LT(tp->snd_wl1, th->th_seq) ||
10482 	    (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) ||
10483 	    (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) {
10484 		/* keep track of pure window updates */
10485 		if (tlen == 0 &&
10486 		    tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd)
10487 			KMOD_TCPSTAT_INC(tcps_rcvwinupd);
10488 		tp->snd_wnd = tiwin;
10489 		rack_validate_fo_sendwin_up(tp, rack);
10490 		tp->snd_wl1 = th->th_seq;
10491 		tp->snd_wl2 = th->th_ack;
10492 		if (tp->snd_wnd > tp->max_sndwnd)
10493 			tp->max_sndwnd = tp->snd_wnd;
10494 		rack->r_wanted_output = 1;
10495 	} else if (thflags & TH_ACK) {
10496 		if ((tp->snd_wl2 == th->th_ack) && (tiwin < tp->snd_wnd)) {
10497 			tp->snd_wnd = tiwin;
10498 			rack_validate_fo_sendwin_up(tp, rack);
10499 			tp->snd_wl1 = th->th_seq;
10500 			tp->snd_wl2 = th->th_ack;
10501 		}
10502 	}
10503 	if (tp->snd_wnd < ctf_outstanding(tp))
10504 		/* The peer collapsed the window */
10505 		rack_collapsed_window(rack, ctf_outstanding(tp), __LINE__);
10506 	else if (rack->rc_has_collapsed)
10507 		rack_un_collapse_window(rack, __LINE__);
10508 	if ((rack->r_collapse_point_valid) &&
10509 	    (SEQ_GT(th->th_ack, rack->r_ctl.high_collapse_point)))
10510 		rack->r_collapse_point_valid = 0;
10511 	/* Was persist timer active and now we have window space? */
10512 	if ((rack->rc_in_persist != 0) &&
10513 	    (tp->snd_wnd >= min((rack->r_ctl.rc_high_rwnd/2),
10514 				rack->r_ctl.rc_pace_min_segs))) {
10515 		rack_exit_persist(tp, rack, rack->r_ctl.rc_rcvtime);
10516 		tp->snd_nxt = tp->snd_max;
10517 		/* Make sure we output to start the timer */
10518 		rack->r_wanted_output = 1;
10519 	}
10520 	/* Do we enter persists? */
10521 	if ((rack->rc_in_persist == 0) &&
10522 	    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), rack->r_ctl.rc_pace_min_segs)) &&
10523 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
10524 	    ((tp->snd_max == tp->snd_una) || rack->rc_has_collapsed) &&
10525 	    sbavail(&tptosocket(tp)->so_snd) &&
10526 	    (sbavail(&tptosocket(tp)->so_snd) > tp->snd_wnd)) {
10527 		/*
10528 		 * Here the rwnd is less than
10529 		 * the pacing size, we are established,
10530 		 * nothing is outstanding, and there is
10531 		 * data to send. Enter persists.
10532 		 */
10533 		rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
10534 	}
10535 	if (tp->t_flags2 & TF2_DROP_AF_DATA) {
10536 		m_freem(m);
10537 		return (0);
10538 	}
10539 	/*
10540 	 * don't process the URG bit, ignore them drag
10541 	 * along the up.
10542 	 */
10543 	tp->rcv_up = tp->rcv_nxt;
10544 
10545 	/*
10546 	 * Process the segment text, merging it into the TCP sequencing
10547 	 * queue, and arranging for acknowledgment of receipt if necessary.
10548 	 * This process logically involves adjusting tp->rcv_wnd as data is
10549 	 * presented to the user (this happens in tcp_usrreq.c, case
10550 	 * PRU_RCVD).  If a FIN has already been received on this connection
10551 	 * then we just ignore the text.
10552 	 */
10553 	tfo_syn = ((tp->t_state == TCPS_SYN_RECEIVED) &&
10554 		   IS_FASTOPEN(tp->t_flags));
10555 	if ((tlen || (thflags & TH_FIN) || (tfo_syn && tlen > 0)) &&
10556 	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
10557 		tcp_seq save_start = th->th_seq;
10558 		tcp_seq save_rnxt  = tp->rcv_nxt;
10559 		int     save_tlen  = tlen;
10560 
10561 		m_adj(m, drop_hdrlen);	/* delayed header drop */
10562 		/*
10563 		 * Insert segment which includes th into TCP reassembly
10564 		 * queue with control block tp.  Set thflags to whether
10565 		 * reassembly now includes a segment with FIN.  This handles
10566 		 * the common case inline (segment is the next to be
10567 		 * received on an established connection, and the queue is
10568 		 * empty), avoiding linkage into and removal from the queue
10569 		 * and repetition of various conversions. Set DELACK for
10570 		 * segments received in order, but ack immediately when
10571 		 * segments are out of order (so fast retransmit can work).
10572 		 */
10573 		if (th->th_seq == tp->rcv_nxt &&
10574 		    SEGQ_EMPTY(tp) &&
10575 		    (TCPS_HAVEESTABLISHED(tp->t_state) ||
10576 		    tfo_syn)) {
10577 #ifdef NETFLIX_SB_LIMITS
10578 			u_int mcnt, appended;
10579 
10580 			if (so->so_rcv.sb_shlim) {
10581 				mcnt = m_memcnt(m);
10582 				appended = 0;
10583 				if (counter_fo_get(so->so_rcv.sb_shlim, mcnt,
10584 				    CFO_NOSLEEP, NULL) == false) {
10585 					counter_u64_add(tcp_sb_shlim_fails, 1);
10586 					m_freem(m);
10587 					return (0);
10588 				}
10589 			}
10590 #endif
10591 			rack_handle_delayed_ack(tp, rack, tlen, tfo_syn);
10592 			tp->rcv_nxt += tlen;
10593 			if (tlen &&
10594 			    ((tp->t_flags2 & TF2_FBYTES_COMPLETE) == 0) &&
10595 			    (tp->t_fbyte_in == 0)) {
10596 				tp->t_fbyte_in = ticks;
10597 				if (tp->t_fbyte_in == 0)
10598 					tp->t_fbyte_in = 1;
10599 				if (tp->t_fbyte_out && tp->t_fbyte_in)
10600 					tp->t_flags2 |= TF2_FBYTES_COMPLETE;
10601 			}
10602 			thflags = tcp_get_flags(th) & TH_FIN;
10603 			KMOD_TCPSTAT_ADD(tcps_rcvpack, nsegs);
10604 			KMOD_TCPSTAT_ADD(tcps_rcvbyte, tlen);
10605 			SOCKBUF_LOCK(&so->so_rcv);
10606 			if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
10607 				m_freem(m);
10608 			} else
10609 #ifdef NETFLIX_SB_LIMITS
10610 				appended =
10611 #endif
10612 					sbappendstream_locked(&so->so_rcv, m, 0);
10613 
10614 			rack_log_wakeup(tp,rack, &so->so_rcv, tlen, 1);
10615 			/* NB: sorwakeup_locked() does an implicit unlock. */
10616 			sorwakeup_locked(so);
10617 #ifdef NETFLIX_SB_LIMITS
10618 			if (so->so_rcv.sb_shlim && appended != mcnt)
10619 				counter_fo_release(so->so_rcv.sb_shlim,
10620 				    mcnt - appended);
10621 #endif
10622 		} else {
10623 			/*
10624 			 * XXX: Due to the header drop above "th" is
10625 			 * theoretically invalid by now.  Fortunately
10626 			 * m_adj() doesn't actually frees any mbufs when
10627 			 * trimming from the head.
10628 			 */
10629 			tcp_seq temp = save_start;
10630 
10631 			thflags = tcp_reass(tp, th, &temp, &tlen, m);
10632 			tp->t_flags |= TF_ACKNOW;
10633 			if (tp->t_flags & TF_WAKESOR) {
10634 				tp->t_flags &= ~TF_WAKESOR;
10635 				/* NB: sorwakeup_locked() does an implicit unlock. */
10636 				sorwakeup_locked(so);
10637 			}
10638 		}
10639 		if ((tp->t_flags & TF_SACK_PERMIT) &&
10640 		    (save_tlen > 0) &&
10641 		    TCPS_HAVEESTABLISHED(tp->t_state)) {
10642 			if ((tlen == 0) && (SEQ_LT(save_start, save_rnxt))) {
10643 				/*
10644 				 * DSACK actually handled in the fastpath
10645 				 * above.
10646 				 */
10647 				RACK_OPTS_INC(tcp_sack_path_1);
10648 				tcp_update_sack_list(tp, save_start,
10649 				    save_start + save_tlen);
10650 			} else if ((tlen > 0) && SEQ_GT(tp->rcv_nxt, save_rnxt)) {
10651 				if ((tp->rcv_numsacks >= 1) &&
10652 				    (tp->sackblks[0].end == save_start)) {
10653 					/*
10654 					 * Partial overlap, recorded at todrop
10655 					 * above.
10656 					 */
10657 					RACK_OPTS_INC(tcp_sack_path_2a);
10658 					tcp_update_sack_list(tp,
10659 					    tp->sackblks[0].start,
10660 					    tp->sackblks[0].end);
10661 				} else {
10662 					RACK_OPTS_INC(tcp_sack_path_2b);
10663 					tcp_update_dsack_list(tp, save_start,
10664 					    save_start + save_tlen);
10665 				}
10666 			} else if (tlen >= save_tlen) {
10667 				/* Update of sackblks. */
10668 				RACK_OPTS_INC(tcp_sack_path_3);
10669 				tcp_update_dsack_list(tp, save_start,
10670 				    save_start + save_tlen);
10671 			} else if (tlen > 0) {
10672 				RACK_OPTS_INC(tcp_sack_path_4);
10673 				tcp_update_dsack_list(tp, save_start,
10674 				    save_start + tlen);
10675 			}
10676 		}
10677 	} else {
10678 		m_freem(m);
10679 		thflags &= ~TH_FIN;
10680 	}
10681 
10682 	/*
10683 	 * If FIN is received ACK the FIN and let the user know that the
10684 	 * connection is closing.
10685 	 */
10686 	if (thflags & TH_FIN) {
10687 		if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
10688 			/* The socket upcall is handled by socantrcvmore. */
10689 			socantrcvmore(so);
10690 			/*
10691 			 * If connection is half-synchronized (ie NEEDSYN
10692 			 * flag on) then delay ACK, so it may be piggybacked
10693 			 * when SYN is sent. Otherwise, since we received a
10694 			 * FIN then no more input can be expected, send ACK
10695 			 * now.
10696 			 */
10697 			if (tp->t_flags & TF_NEEDSYN) {
10698 				rack_timer_cancel(tp, rack,
10699 				    rack->r_ctl.rc_rcvtime, __LINE__);
10700 				tp->t_flags |= TF_DELACK;
10701 			} else {
10702 				tp->t_flags |= TF_ACKNOW;
10703 			}
10704 			tp->rcv_nxt++;
10705 		}
10706 		switch (tp->t_state) {
10707 			/*
10708 			 * In SYN_RECEIVED and ESTABLISHED STATES enter the
10709 			 * CLOSE_WAIT state.
10710 			 */
10711 		case TCPS_SYN_RECEIVED:
10712 			tp->t_starttime = ticks;
10713 			/* FALLTHROUGH */
10714 		case TCPS_ESTABLISHED:
10715 			rack_timer_cancel(tp, rack,
10716 			    rack->r_ctl.rc_rcvtime, __LINE__);
10717 			tcp_state_change(tp, TCPS_CLOSE_WAIT);
10718 			break;
10719 
10720 			/*
10721 			 * If still in FIN_WAIT_1 STATE FIN has not been
10722 			 * acked so enter the CLOSING state.
10723 			 */
10724 		case TCPS_FIN_WAIT_1:
10725 			rack_timer_cancel(tp, rack,
10726 			    rack->r_ctl.rc_rcvtime, __LINE__);
10727 			tcp_state_change(tp, TCPS_CLOSING);
10728 			break;
10729 
10730 			/*
10731 			 * In FIN_WAIT_2 state enter the TIME_WAIT state,
10732 			 * starting the time-wait timer, turning off the
10733 			 * other standard timers.
10734 			 */
10735 		case TCPS_FIN_WAIT_2:
10736 			rack_timer_cancel(tp, rack,
10737 			    rack->r_ctl.rc_rcvtime, __LINE__);
10738 			tcp_twstart(tp);
10739 			return (1);
10740 		}
10741 	}
10742 	/*
10743 	 * Return any desired output.
10744 	 */
10745 	if ((tp->t_flags & TF_ACKNOW) ||
10746 	    (sbavail(&so->so_snd) > (tp->snd_max - tp->snd_una))) {
10747 		rack->r_wanted_output = 1;
10748 	}
10749 	return (0);
10750 }
10751 
10752 /*
10753  * Here nothing is really faster, its just that we
10754  * have broken out the fast-data path also just like
10755  * the fast-ack.
10756  */
10757 static int
10758 rack_do_fastnewdata(struct mbuf *m, struct tcphdr *th, struct socket *so,
10759     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
10760     uint32_t tiwin, int32_t nxt_pkt, uint8_t iptos)
10761 {
10762 	int32_t nsegs;
10763 	int32_t newsize = 0;	/* automatic sockbuf scaling */
10764 	struct tcp_rack *rack;
10765 #ifdef NETFLIX_SB_LIMITS
10766 	u_int mcnt, appended;
10767 #endif
10768 
10769 	/*
10770 	 * If last ACK falls within this segment's sequence numbers, record
10771 	 * the timestamp. NOTE that the test is modified according to the
10772 	 * latest proposal of the tcplw@cray.com list (Braden 1993/04/26).
10773 	 */
10774 	if (__predict_false(th->th_seq != tp->rcv_nxt)) {
10775 		return (0);
10776 	}
10777 	if (__predict_false(tp->snd_nxt != tp->snd_max)) {
10778 		return (0);
10779 	}
10780 	if (tiwin && tiwin != tp->snd_wnd) {
10781 		return (0);
10782 	}
10783 	if (__predict_false((tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN)))) {
10784 		return (0);
10785 	}
10786 	if (__predict_false((to->to_flags & TOF_TS) &&
10787 	    (TSTMP_LT(to->to_tsval, tp->ts_recent)))) {
10788 		return (0);
10789 	}
10790 	if (__predict_false((th->th_ack != tp->snd_una))) {
10791 		return (0);
10792 	}
10793 	if (__predict_false(tlen > sbspace(&so->so_rcv))) {
10794 		return (0);
10795 	}
10796 	if ((to->to_flags & TOF_TS) != 0 &&
10797 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
10798 		tp->ts_recent_age = tcp_ts_getticks();
10799 		tp->ts_recent = to->to_tsval;
10800 	}
10801 	rack = (struct tcp_rack *)tp->t_fb_ptr;
10802 	/*
10803 	 * This is a pure, in-sequence data packet with nothing on the
10804 	 * reassembly queue and we have enough buffer space to take it.
10805 	 */
10806 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
10807 
10808 #ifdef NETFLIX_SB_LIMITS
10809 	if (so->so_rcv.sb_shlim) {
10810 		mcnt = m_memcnt(m);
10811 		appended = 0;
10812 		if (counter_fo_get(so->so_rcv.sb_shlim, mcnt,
10813 		    CFO_NOSLEEP, NULL) == false) {
10814 			counter_u64_add(tcp_sb_shlim_fails, 1);
10815 			m_freem(m);
10816 			return (1);
10817 		}
10818 	}
10819 #endif
10820 	/* Clean receiver SACK report if present */
10821 	if (tp->rcv_numsacks)
10822 		tcp_clean_sackreport(tp);
10823 	KMOD_TCPSTAT_INC(tcps_preddat);
10824 	tp->rcv_nxt += tlen;
10825 	if (tlen &&
10826 	    ((tp->t_flags2 & TF2_FBYTES_COMPLETE) == 0) &&
10827 	    (tp->t_fbyte_in == 0)) {
10828 		tp->t_fbyte_in = ticks;
10829 		if (tp->t_fbyte_in == 0)
10830 			tp->t_fbyte_in = 1;
10831 		if (tp->t_fbyte_out && tp->t_fbyte_in)
10832 			tp->t_flags2 |= TF2_FBYTES_COMPLETE;
10833 	}
10834 	/*
10835 	 * Pull snd_wl1 up to prevent seq wrap relative to th_seq.
10836 	 */
10837 	tp->snd_wl1 = th->th_seq;
10838 	/*
10839 	 * Pull rcv_up up to prevent seq wrap relative to rcv_nxt.
10840 	 */
10841 	tp->rcv_up = tp->rcv_nxt;
10842 	KMOD_TCPSTAT_ADD(tcps_rcvpack, nsegs);
10843 	KMOD_TCPSTAT_ADD(tcps_rcvbyte, tlen);
10844 	newsize = tcp_autorcvbuf(m, th, so, tp, tlen);
10845 
10846 	/* Add data to socket buffer. */
10847 	SOCKBUF_LOCK(&so->so_rcv);
10848 	if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
10849 		m_freem(m);
10850 	} else {
10851 		/*
10852 		 * Set new socket buffer size. Give up when limit is
10853 		 * reached.
10854 		 */
10855 		if (newsize)
10856 			if (!sbreserve_locked(so, SO_RCV, newsize, NULL))
10857 				so->so_rcv.sb_flags &= ~SB_AUTOSIZE;
10858 		m_adj(m, drop_hdrlen);	/* delayed header drop */
10859 #ifdef NETFLIX_SB_LIMITS
10860 		appended =
10861 #endif
10862 			sbappendstream_locked(&so->so_rcv, m, 0);
10863 		ctf_calc_rwin(so, tp);
10864 	}
10865 	rack_log_wakeup(tp,rack, &so->so_rcv, tlen, 1);
10866 	/* NB: sorwakeup_locked() does an implicit unlock. */
10867 	sorwakeup_locked(so);
10868 #ifdef NETFLIX_SB_LIMITS
10869 	if (so->so_rcv.sb_shlim && mcnt != appended)
10870 		counter_fo_release(so->so_rcv.sb_shlim, mcnt - appended);
10871 #endif
10872 	rack_handle_delayed_ack(tp, rack, tlen, 0);
10873 	if (tp->snd_una == tp->snd_max)
10874 		sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
10875 	return (1);
10876 }
10877 
10878 /*
10879  * This subfunction is used to try to highly optimize the
10880  * fast path. We again allow window updates that are
10881  * in sequence to remain in the fast-path. We also add
10882  * in the __predict's to attempt to help the compiler.
10883  * Note that if we return a 0, then we can *not* process
10884  * it and the caller should push the packet into the
10885  * slow-path.
10886  */
10887 static int
10888 rack_fastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
10889     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
10890     uint32_t tiwin, int32_t nxt_pkt, uint32_t cts)
10891 {
10892 	int32_t acked;
10893 	int32_t nsegs;
10894 	int32_t under_pacing = 0;
10895 	struct tcp_rack *rack;
10896 
10897 	if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
10898 		/* Old ack, behind (or duplicate to) the last one rcv'd */
10899 		return (0);
10900 	}
10901 	if (__predict_false(SEQ_GT(th->th_ack, tp->snd_max))) {
10902 		/* Above what we have sent? */
10903 		return (0);
10904 	}
10905 	if (__predict_false(tp->snd_nxt != tp->snd_max)) {
10906 		/* We are retransmitting */
10907 		return (0);
10908 	}
10909 	if (__predict_false(tiwin == 0)) {
10910 		/* zero window */
10911 		return (0);
10912 	}
10913 	if (__predict_false(tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN))) {
10914 		/* We need a SYN or a FIN, unlikely.. */
10915 		return (0);
10916 	}
10917 	if ((to->to_flags & TOF_TS) && __predict_false(TSTMP_LT(to->to_tsval, tp->ts_recent))) {
10918 		/* Timestamp is behind .. old ack with seq wrap? */
10919 		return (0);
10920 	}
10921 	if (__predict_false(IN_RECOVERY(tp->t_flags))) {
10922 		/* Still recovering */
10923 		return (0);
10924 	}
10925 	rack = (struct tcp_rack *)tp->t_fb_ptr;
10926 	if (rack->r_ctl.rc_sacked) {
10927 		/* We have sack holes on our scoreboard */
10928 		return (0);
10929 	}
10930 	/* Ok if we reach here, we can process a fast-ack */
10931 	if (rack->gp_ready &&
10932 	    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
10933 		under_pacing = 1;
10934 	}
10935 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
10936 	rack_log_ack(tp, to, th, 0, 0);
10937 	/* Did the window get updated? */
10938 	if (tiwin != tp->snd_wnd) {
10939 		tp->snd_wnd = tiwin;
10940 		rack_validate_fo_sendwin_up(tp, rack);
10941 		tp->snd_wl1 = th->th_seq;
10942 		if (tp->snd_wnd > tp->max_sndwnd)
10943 			tp->max_sndwnd = tp->snd_wnd;
10944 	}
10945 	/* Do we exit persists? */
10946 	if ((rack->rc_in_persist != 0) &&
10947 	    (tp->snd_wnd >= min((rack->r_ctl.rc_high_rwnd/2),
10948 			       rack->r_ctl.rc_pace_min_segs))) {
10949 		rack_exit_persist(tp, rack, cts);
10950 	}
10951 	/* Do we enter persists? */
10952 	if ((rack->rc_in_persist == 0) &&
10953 	    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), rack->r_ctl.rc_pace_min_segs)) &&
10954 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
10955 	    ((tp->snd_max == tp->snd_una) || rack->rc_has_collapsed) &&
10956 	    sbavail(&tptosocket(tp)->so_snd) &&
10957 	    (sbavail(&tptosocket(tp)->so_snd) > tp->snd_wnd)) {
10958 		/*
10959 		 * Here the rwnd is less than
10960 		 * the pacing size, we are established,
10961 		 * nothing is outstanding, and there is
10962 		 * data to send. Enter persists.
10963 		 */
10964 		rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
10965 	}
10966 	/*
10967 	 * If last ACK falls within this segment's sequence numbers, record
10968 	 * the timestamp. NOTE that the test is modified according to the
10969 	 * latest proposal of the tcplw@cray.com list (Braden 1993/04/26).
10970 	 */
10971 	if ((to->to_flags & TOF_TS) != 0 &&
10972 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
10973 		tp->ts_recent_age = tcp_ts_getticks();
10974 		tp->ts_recent = to->to_tsval;
10975 	}
10976 	/*
10977 	 * This is a pure ack for outstanding data.
10978 	 */
10979 	KMOD_TCPSTAT_INC(tcps_predack);
10980 
10981 	/*
10982 	 * "bad retransmit" recovery.
10983 	 */
10984 	if ((tp->t_flags & TF_PREVVALID) &&
10985 	    ((tp->t_flags & TF_RCVD_TSTMP) == 0)) {
10986 		tp->t_flags &= ~TF_PREVVALID;
10987 		if (tp->t_rxtshift == 1 &&
10988 		    (int)(ticks - tp->t_badrxtwin) < 0)
10989 			rack_cong_signal(tp, CC_RTO_ERR, th->th_ack, __LINE__);
10990 	}
10991 	/*
10992 	 * Recalculate the transmit timer / rtt.
10993 	 *
10994 	 * Some boxes send broken timestamp replies during the SYN+ACK
10995 	 * phase, ignore timestamps of 0 or we could calculate a huge RTT
10996 	 * and blow up the retransmit timer.
10997 	 */
10998 	acked = BYTES_THIS_ACK(tp, th);
10999 
11000 #ifdef TCP_HHOOK
11001 	/* Run HHOOK_TCP_ESTABLISHED_IN helper hooks. */
11002 	hhook_run_tcp_est_in(tp, th, to);
11003 #endif
11004 	KMOD_TCPSTAT_ADD(tcps_rcvackpack, nsegs);
11005 	KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
11006 	if (acked) {
11007 		struct mbuf *mfree;
11008 
11009 		rack_ack_received(tp, rack, th->th_ack, nsegs, CC_ACK, 0);
11010 		SOCKBUF_LOCK(&so->so_snd);
11011 		mfree = sbcut_locked(&so->so_snd, acked);
11012 		tp->snd_una = th->th_ack;
11013 		/* Note we want to hold the sb lock through the sendmap adjust */
11014 		rack_adjust_sendmap(rack, &so->so_snd, tp->snd_una);
11015 		/* Wake up the socket if we have room to write more */
11016 		rack_log_wakeup(tp,rack, &so->so_snd, acked, 2);
11017 		sowwakeup_locked(so);
11018 		m_freem(mfree);
11019 		tp->t_rxtshift = 0;
11020 		RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
11021 			      rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
11022 		rack->rc_tlp_in_progress = 0;
11023 		rack->r_ctl.rc_tlp_cnt_out = 0;
11024 		/*
11025 		 * If it is the RXT timer we want to
11026 		 * stop it, so we can restart a TLP.
11027 		 */
11028 		if (rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT)
11029 			rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
11030 #ifdef NETFLIX_HTTP_LOGGING
11031 		tcp_http_check_for_comp(rack->rc_tp, th->th_ack);
11032 #endif
11033 	}
11034 	/*
11035 	 * Let the congestion control algorithm update congestion control
11036 	 * related information. This typically means increasing the
11037 	 * congestion window.
11038 	 */
11039 	if (tp->snd_wnd < ctf_outstanding(tp)) {
11040 		/* The peer collapsed the window */
11041 		rack_collapsed_window(rack, ctf_outstanding(tp), __LINE__);
11042 	} else if (rack->rc_has_collapsed)
11043 		rack_un_collapse_window(rack, __LINE__);
11044 	if ((rack->r_collapse_point_valid) &&
11045 	    (SEQ_GT(tp->snd_una, rack->r_ctl.high_collapse_point)))
11046 		rack->r_collapse_point_valid = 0;
11047 	/*
11048 	 * Pull snd_wl2 up to prevent seq wrap relative to th_ack.
11049 	 */
11050 	tp->snd_wl2 = th->th_ack;
11051 	tp->t_dupacks = 0;
11052 	m_freem(m);
11053 	/* ND6_HINT(tp);	 *//* Some progress has been made. */
11054 
11055 	/*
11056 	 * If all outstanding data are acked, stop retransmit timer,
11057 	 * otherwise restart timer using current (possibly backed-off)
11058 	 * value. If process is waiting for space, wakeup/selwakeup/signal.
11059 	 * If data are ready to send, let tcp_output decide between more
11060 	 * output or persist.
11061 	 */
11062 	if (under_pacing &&
11063 	    (rack->use_fixed_rate == 0) &&
11064 	    (rack->in_probe_rtt == 0) &&
11065 	    rack->rc_gp_dyn_mul &&
11066 	    rack->rc_always_pace) {
11067 		/* Check if we are dragging bottom */
11068 		rack_check_bottom_drag(tp, rack, so, acked);
11069 	}
11070 	if (tp->snd_una == tp->snd_max) {
11071 		tp->t_flags &= ~TF_PREVVALID;
11072 		rack->r_ctl.retran_during_recovery = 0;
11073 		rack->r_ctl.dsack_byte_cnt = 0;
11074 		rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
11075 		if (rack->r_ctl.rc_went_idle_time == 0)
11076 			rack->r_ctl.rc_went_idle_time = 1;
11077 		rack_log_progress_event(rack, tp, 0, PROGRESS_CLEAR, __LINE__);
11078 		if (sbavail(&tptosocket(tp)->so_snd) == 0)
11079 			tp->t_acktime = 0;
11080 		rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
11081 	}
11082 	if (acked && rack->r_fast_output)
11083 		rack_gain_for_fastoutput(rack, tp, so, (uint32_t)acked);
11084 	if (sbavail(&so->so_snd)) {
11085 		rack->r_wanted_output = 1;
11086 	}
11087 	return (1);
11088 }
11089 
11090 /*
11091  * Return value of 1, the TCB is unlocked and most
11092  * likely gone, return value of 0, the TCP is still
11093  * locked.
11094  */
11095 static int
11096 rack_do_syn_sent(struct mbuf *m, struct tcphdr *th, struct socket *so,
11097     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
11098     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
11099 {
11100 	int32_t ret_val = 0;
11101 	int32_t todrop;
11102 	int32_t ourfinisacked = 0;
11103 	struct tcp_rack *rack;
11104 
11105 	INP_WLOCK_ASSERT(tptoinpcb(tp));
11106 
11107 	ctf_calc_rwin(so, tp);
11108 	/*
11109 	 * If the state is SYN_SENT: if seg contains an ACK, but not for our
11110 	 * SYN, drop the input. if seg contains a RST, then drop the
11111 	 * connection. if seg does not contain SYN, then drop it. Otherwise
11112 	 * this is an acceptable SYN segment initialize tp->rcv_nxt and
11113 	 * tp->irs if seg contains ack then advance tp->snd_una if seg
11114 	 * contains an ECE and ECN support is enabled, the stream is ECN
11115 	 * capable. if SYN has been acked change to ESTABLISHED else
11116 	 * SYN_RCVD state arrange for segment to be acked (eventually)
11117 	 * continue processing rest of data/controls.
11118 	 */
11119 	if ((thflags & TH_ACK) &&
11120 	    (SEQ_LEQ(th->th_ack, tp->iss) ||
11121 	    SEQ_GT(th->th_ack, tp->snd_max))) {
11122 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
11123 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11124 		return (1);
11125 	}
11126 	if ((thflags & (TH_ACK | TH_RST)) == (TH_ACK | TH_RST)) {
11127 		TCP_PROBE5(connect__refused, NULL, tp,
11128 		    mtod(m, const char *), tp, th);
11129 		tp = tcp_drop(tp, ECONNREFUSED);
11130 		ctf_do_drop(m, tp);
11131 		return (1);
11132 	}
11133 	if (thflags & TH_RST) {
11134 		ctf_do_drop(m, tp);
11135 		return (1);
11136 	}
11137 	if (!(thflags & TH_SYN)) {
11138 		ctf_do_drop(m, tp);
11139 		return (1);
11140 	}
11141 	tp->irs = th->th_seq;
11142 	tcp_rcvseqinit(tp);
11143 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11144 	if (thflags & TH_ACK) {
11145 		int tfo_partial = 0;
11146 
11147 		KMOD_TCPSTAT_INC(tcps_connects);
11148 		soisconnected(so);
11149 #ifdef MAC
11150 		mac_socketpeer_set_from_mbuf(m, so);
11151 #endif
11152 		/* Do window scaling on this connection? */
11153 		if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
11154 		    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
11155 			tp->rcv_scale = tp->request_r_scale;
11156 		}
11157 		tp->rcv_adv += min(tp->rcv_wnd,
11158 		    TCP_MAXWIN << tp->rcv_scale);
11159 		/*
11160 		 * If not all the data that was sent in the TFO SYN
11161 		 * has been acked, resend the remainder right away.
11162 		 */
11163 		if (IS_FASTOPEN(tp->t_flags) &&
11164 		    (tp->snd_una != tp->snd_max)) {
11165 			tp->snd_nxt = th->th_ack;
11166 			tfo_partial = 1;
11167 		}
11168 		/*
11169 		 * If there's data, delay ACK; if there's also a FIN ACKNOW
11170 		 * will be turned on later.
11171 		 */
11172 		if (DELAY_ACK(tp, tlen) && tlen != 0 && !tfo_partial) {
11173 			rack_timer_cancel(tp, rack,
11174 					  rack->r_ctl.rc_rcvtime, __LINE__);
11175 			tp->t_flags |= TF_DELACK;
11176 		} else {
11177 			rack->r_wanted_output = 1;
11178 			tp->t_flags |= TF_ACKNOW;
11179 			rack->rc_dack_toggle = 0;
11180 		}
11181 
11182 		tcp_ecn_input_syn_sent(tp, thflags, iptos);
11183 
11184 		if (SEQ_GT(th->th_ack, tp->snd_una)) {
11185 			/*
11186 			 * We advance snd_una for the
11187 			 * fast open case. If th_ack is
11188 			 * acknowledging data beyond
11189 			 * snd_una we can't just call
11190 			 * ack-processing since the
11191 			 * data stream in our send-map
11192 			 * will start at snd_una + 1 (one
11193 			 * beyond the SYN). If its just
11194 			 * equal we don't need to do that
11195 			 * and there is no send_map.
11196 			 */
11197 			tp->snd_una++;
11198 		}
11199 		/*
11200 		 * Received <SYN,ACK> in SYN_SENT[*] state. Transitions:
11201 		 * SYN_SENT  --> ESTABLISHED SYN_SENT* --> FIN_WAIT_1
11202 		 */
11203 		tp->t_starttime = ticks;
11204 		if (tp->t_flags & TF_NEEDFIN) {
11205 			tcp_state_change(tp, TCPS_FIN_WAIT_1);
11206 			tp->t_flags &= ~TF_NEEDFIN;
11207 			thflags &= ~TH_SYN;
11208 		} else {
11209 			tcp_state_change(tp, TCPS_ESTABLISHED);
11210 			TCP_PROBE5(connect__established, NULL, tp,
11211 			    mtod(m, const char *), tp, th);
11212 			rack_cc_conn_init(tp);
11213 		}
11214 	} else {
11215 		/*
11216 		 * Received initial SYN in SYN-SENT[*] state => simultaneous
11217 		 * open.  If segment contains CC option and there is a
11218 		 * cached CC, apply TAO test. If it succeeds, connection is *
11219 		 * half-synchronized. Otherwise, do 3-way handshake:
11220 		 * SYN-SENT -> SYN-RECEIVED SYN-SENT* -> SYN-RECEIVED* If
11221 		 * there was no CC option, clear cached CC value.
11222 		 */
11223 		tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN | TF_SONOTCONN);
11224 		tcp_state_change(tp, TCPS_SYN_RECEIVED);
11225 	}
11226 	/*
11227 	 * Advance th->th_seq to correspond to first data byte. If data,
11228 	 * trim to stay within window, dropping FIN if necessary.
11229 	 */
11230 	th->th_seq++;
11231 	if (tlen > tp->rcv_wnd) {
11232 		todrop = tlen - tp->rcv_wnd;
11233 		m_adj(m, -todrop);
11234 		tlen = tp->rcv_wnd;
11235 		thflags &= ~TH_FIN;
11236 		KMOD_TCPSTAT_INC(tcps_rcvpackafterwin);
11237 		KMOD_TCPSTAT_ADD(tcps_rcvbyteafterwin, todrop);
11238 	}
11239 	tp->snd_wl1 = th->th_seq - 1;
11240 	tp->rcv_up = th->th_seq;
11241 	/*
11242 	 * Client side of transaction: already sent SYN and data. If the
11243 	 * remote host used T/TCP to validate the SYN, our data will be
11244 	 * ACK'd; if so, enter normal data segment processing in the middle
11245 	 * of step 5, ack processing. Otherwise, goto step 6.
11246 	 */
11247 	if (thflags & TH_ACK) {
11248 		/* For syn-sent we need to possibly update the rtt */
11249 		if ((to->to_flags & TOF_TS) != 0 && to->to_tsecr) {
11250 			uint32_t t, mcts;
11251 
11252 			mcts = tcp_ts_getticks();
11253 			t = (mcts - to->to_tsecr) * HPTS_USEC_IN_MSEC;
11254 			if (!tp->t_rttlow || tp->t_rttlow > t)
11255 				tp->t_rttlow = t;
11256 			rack_log_rtt_sample_calc(rack, t, (to->to_tsecr * 1000), (mcts * 1000), 4);
11257 			tcp_rack_xmit_timer(rack, t + 1, 1, t, 0, NULL, 2);
11258 			tcp_rack_xmit_timer_commit(rack, tp);
11259 		}
11260 		if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val))
11261 			return (ret_val);
11262 		/* We may have changed to FIN_WAIT_1 above */
11263 		if (tp->t_state == TCPS_FIN_WAIT_1) {
11264 			/*
11265 			 * In FIN_WAIT_1 STATE in addition to the processing
11266 			 * for the ESTABLISHED state if our FIN is now
11267 			 * acknowledged then enter FIN_WAIT_2.
11268 			 */
11269 			if (ourfinisacked) {
11270 				/*
11271 				 * If we can't receive any more data, then
11272 				 * closing user can proceed. Starting the
11273 				 * timer is contrary to the specification,
11274 				 * but if we don't get a FIN we'll hang
11275 				 * forever.
11276 				 *
11277 				 * XXXjl: we should release the tp also, and
11278 				 * use a compressed state.
11279 				 */
11280 				if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
11281 					soisdisconnected(so);
11282 					tcp_timer_activate(tp, TT_2MSL,
11283 					    (tcp_fast_finwait2_recycle ?
11284 					    tcp_finwait2_timeout :
11285 					    TP_MAXIDLE(tp)));
11286 				}
11287 				tcp_state_change(tp, TCPS_FIN_WAIT_2);
11288 			}
11289 		}
11290 	}
11291 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11292 	   tiwin, thflags, nxt_pkt));
11293 }
11294 
11295 /*
11296  * Return value of 1, the TCB is unlocked and most
11297  * likely gone, return value of 0, the TCP is still
11298  * locked.
11299  */
11300 static int
11301 rack_do_syn_recv(struct mbuf *m, struct tcphdr *th, struct socket *so,
11302     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
11303     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
11304 {
11305 	struct tcp_rack *rack;
11306 	int32_t ret_val = 0;
11307 	int32_t ourfinisacked = 0;
11308 
11309 	ctf_calc_rwin(so, tp);
11310 	if ((thflags & TH_ACK) &&
11311 	    (SEQ_LEQ(th->th_ack, tp->snd_una) ||
11312 	    SEQ_GT(th->th_ack, tp->snd_max))) {
11313 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
11314 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11315 		return (1);
11316 	}
11317 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11318 	if (IS_FASTOPEN(tp->t_flags)) {
11319 		/*
11320 		 * When a TFO connection is in SYN_RECEIVED, the
11321 		 * only valid packets are the initial SYN, a
11322 		 * retransmit/copy of the initial SYN (possibly with
11323 		 * a subset of the original data), a valid ACK, a
11324 		 * FIN, or a RST.
11325 		 */
11326 		if ((thflags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) {
11327 			tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
11328 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11329 			return (1);
11330 		} else if (thflags & TH_SYN) {
11331 			/* non-initial SYN is ignored */
11332 			if ((rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT) ||
11333 			    (rack->r_ctl.rc_hpts_flags & PACE_TMR_TLP) ||
11334 			    (rack->r_ctl.rc_hpts_flags & PACE_TMR_RACK)) {
11335 				ctf_do_drop(m, NULL);
11336 				return (0);
11337 			}
11338 		} else if (!(thflags & (TH_ACK | TH_FIN | TH_RST))) {
11339 			ctf_do_drop(m, NULL);
11340 			return (0);
11341 		}
11342 	}
11343 
11344 	if ((thflags & TH_RST) ||
11345 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
11346 		return (__ctf_process_rst(m, th, so, tp,
11347 					  &rack->r_ctl.challenge_ack_ts,
11348 					  &rack->r_ctl.challenge_ack_cnt));
11349 	/*
11350 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
11351 	 * it's less than ts_recent, drop it.
11352 	 */
11353 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
11354 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
11355 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
11356 			return (ret_val);
11357 	}
11358 	/*
11359 	 * In the SYN-RECEIVED state, validate that the packet belongs to
11360 	 * this connection before trimming the data to fit the receive
11361 	 * window.  Check the sequence number versus IRS since we know the
11362 	 * sequence numbers haven't wrapped.  This is a partial fix for the
11363 	 * "LAND" DoS attack.
11364 	 */
11365 	if (SEQ_LT(th->th_seq, tp->irs)) {
11366 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
11367 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11368 		return (1);
11369 	}
11370 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
11371 			      &rack->r_ctl.challenge_ack_ts,
11372 			      &rack->r_ctl.challenge_ack_cnt)) {
11373 		return (ret_val);
11374 	}
11375 	/*
11376 	 * If last ACK falls within this segment's sequence numbers, record
11377 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
11378 	 * from the latest proposal of the tcplw@cray.com list (Braden
11379 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
11380 	 * with our earlier PAWS tests, so this check should be solely
11381 	 * predicated on the sequence space of this segment. 3) That we
11382 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
11383 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
11384 	 * SEG.Len, This modified check allows us to overcome RFC1323's
11385 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
11386 	 * p.869. In such cases, we can still calculate the RTT correctly
11387 	 * when RCV.NXT == Last.ACK.Sent.
11388 	 */
11389 	if ((to->to_flags & TOF_TS) != 0 &&
11390 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
11391 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
11392 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
11393 		tp->ts_recent_age = tcp_ts_getticks();
11394 		tp->ts_recent = to->to_tsval;
11395 	}
11396 	tp->snd_wnd = tiwin;
11397 	rack_validate_fo_sendwin_up(tp, rack);
11398 	/*
11399 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
11400 	 * is on (half-synchronized state), then queue data for later
11401 	 * processing; else drop segment and return.
11402 	 */
11403 	if ((thflags & TH_ACK) == 0) {
11404 		if (IS_FASTOPEN(tp->t_flags)) {
11405 			rack_cc_conn_init(tp);
11406 		}
11407 		return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11408 		    tiwin, thflags, nxt_pkt));
11409 	}
11410 	KMOD_TCPSTAT_INC(tcps_connects);
11411 	if (tp->t_flags & TF_SONOTCONN) {
11412 		tp->t_flags &= ~TF_SONOTCONN;
11413 		soisconnected(so);
11414 	}
11415 	/* Do window scaling? */
11416 	if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
11417 	    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
11418 		tp->rcv_scale = tp->request_r_scale;
11419 	}
11420 	/*
11421 	 * Make transitions: SYN-RECEIVED  -> ESTABLISHED SYN-RECEIVED* ->
11422 	 * FIN-WAIT-1
11423 	 */
11424 	tp->t_starttime = ticks;
11425 	if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) {
11426 		tcp_fastopen_decrement_counter(tp->t_tfo_pending);
11427 		tp->t_tfo_pending = NULL;
11428 	}
11429 	if (tp->t_flags & TF_NEEDFIN) {
11430 		tcp_state_change(tp, TCPS_FIN_WAIT_1);
11431 		tp->t_flags &= ~TF_NEEDFIN;
11432 	} else {
11433 		tcp_state_change(tp, TCPS_ESTABLISHED);
11434 		TCP_PROBE5(accept__established, NULL, tp,
11435 		    mtod(m, const char *), tp, th);
11436 		/*
11437 		 * TFO connections call cc_conn_init() during SYN
11438 		 * processing.  Calling it again here for such connections
11439 		 * is not harmless as it would undo the snd_cwnd reduction
11440 		 * that occurs when a TFO SYN|ACK is retransmitted.
11441 		 */
11442 		if (!IS_FASTOPEN(tp->t_flags))
11443 			rack_cc_conn_init(tp);
11444 	}
11445 	/*
11446 	 * Account for the ACK of our SYN prior to
11447 	 * regular ACK processing below, except for
11448 	 * simultaneous SYN, which is handled later.
11449 	 */
11450 	if (SEQ_GT(th->th_ack, tp->snd_una) && !(tp->t_flags & TF_NEEDSYN))
11451 		tp->snd_una++;
11452 	/*
11453 	 * If segment contains data or ACK, will call tcp_reass() later; if
11454 	 * not, do so now to pass queued data to user.
11455 	 */
11456 	if (tlen == 0 && (thflags & TH_FIN) == 0) {
11457 		(void) tcp_reass(tp, (struct tcphdr *)0, NULL, 0,
11458 		    (struct mbuf *)0);
11459 		if (tp->t_flags & TF_WAKESOR) {
11460 			tp->t_flags &= ~TF_WAKESOR;
11461 			/* NB: sorwakeup_locked() does an implicit unlock. */
11462 			sorwakeup_locked(so);
11463 		}
11464 	}
11465 	tp->snd_wl1 = th->th_seq - 1;
11466 	/* For syn-recv we need to possibly update the rtt */
11467 	if ((to->to_flags & TOF_TS) != 0 && to->to_tsecr) {
11468 		uint32_t t, mcts;
11469 
11470 		mcts = tcp_ts_getticks();
11471 		t = (mcts - to->to_tsecr) * HPTS_USEC_IN_MSEC;
11472 		if (!tp->t_rttlow || tp->t_rttlow > t)
11473 			tp->t_rttlow = t;
11474 		rack_log_rtt_sample_calc(rack, t, (to->to_tsecr * 1000), (mcts * 1000), 5);
11475 		tcp_rack_xmit_timer(rack, t + 1, 1, t, 0, NULL, 2);
11476 		tcp_rack_xmit_timer_commit(rack, tp);
11477 	}
11478 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
11479 		return (ret_val);
11480 	}
11481 	if (tp->t_state == TCPS_FIN_WAIT_1) {
11482 		/* We could have went to FIN_WAIT_1 (or EST) above */
11483 		/*
11484 		 * In FIN_WAIT_1 STATE in addition to the processing for the
11485 		 * ESTABLISHED state if our FIN is now acknowledged then
11486 		 * enter FIN_WAIT_2.
11487 		 */
11488 		if (ourfinisacked) {
11489 			/*
11490 			 * If we can't receive any more data, then closing
11491 			 * user can proceed. Starting the timer is contrary
11492 			 * to the specification, but if we don't get a FIN
11493 			 * we'll hang forever.
11494 			 *
11495 			 * XXXjl: we should release the tp also, and use a
11496 			 * compressed state.
11497 			 */
11498 			if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
11499 				soisdisconnected(so);
11500 				tcp_timer_activate(tp, TT_2MSL,
11501 				    (tcp_fast_finwait2_recycle ?
11502 				    tcp_finwait2_timeout :
11503 				    TP_MAXIDLE(tp)));
11504 			}
11505 			tcp_state_change(tp, TCPS_FIN_WAIT_2);
11506 		}
11507 	}
11508 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11509 	    tiwin, thflags, nxt_pkt));
11510 }
11511 
11512 /*
11513  * Return value of 1, the TCB is unlocked and most
11514  * likely gone, return value of 0, the TCP is still
11515  * locked.
11516  */
11517 static int
11518 rack_do_established(struct mbuf *m, struct tcphdr *th, struct socket *so,
11519     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
11520     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
11521 {
11522 	int32_t ret_val = 0;
11523 	struct tcp_rack *rack;
11524 
11525 	/*
11526 	 * Header prediction: check for the two common cases of a
11527 	 * uni-directional data xfer.  If the packet has no control flags,
11528 	 * is in-sequence, the window didn't change and we're not
11529 	 * retransmitting, it's a candidate.  If the length is zero and the
11530 	 * ack moved forward, we're the sender side of the xfer.  Just free
11531 	 * the data acked & wake any higher level process that was blocked
11532 	 * waiting for space.  If the length is non-zero and the ack didn't
11533 	 * move, we're the receiver side.  If we're getting packets in-order
11534 	 * (the reassembly queue is empty), add the data toc The socket
11535 	 * buffer and note that we need a delayed ack. Make sure that the
11536 	 * hidden state-flags are also off. Since we check for
11537 	 * TCPS_ESTABLISHED first, it can only be TH_NEEDSYN.
11538 	 */
11539 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11540 	if (__predict_true(((to->to_flags & TOF_SACK) == 0)) &&
11541 	    __predict_true((thflags & (TH_SYN | TH_FIN | TH_RST | TH_ACK)) == TH_ACK) &&
11542 	    __predict_true(SEGQ_EMPTY(tp)) &&
11543 	    __predict_true(th->th_seq == tp->rcv_nxt)) {
11544 		if (tlen == 0) {
11545 			if (rack_fastack(m, th, so, tp, to, drop_hdrlen, tlen,
11546 			    tiwin, nxt_pkt, rack->r_ctl.rc_rcvtime)) {
11547 				return (0);
11548 			}
11549 		} else {
11550 			if (rack_do_fastnewdata(m, th, so, tp, to, drop_hdrlen, tlen,
11551 			    tiwin, nxt_pkt, iptos)) {
11552 				return (0);
11553 			}
11554 		}
11555 	}
11556 	ctf_calc_rwin(so, tp);
11557 
11558 	if ((thflags & TH_RST) ||
11559 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
11560 		return (__ctf_process_rst(m, th, so, tp,
11561 					  &rack->r_ctl.challenge_ack_ts,
11562 					  &rack->r_ctl.challenge_ack_cnt));
11563 
11564 	/*
11565 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
11566 	 * synchronized state.
11567 	 */
11568 	if (thflags & TH_SYN) {
11569 		ctf_challenge_ack(m, th, tp, iptos, &ret_val);
11570 		return (ret_val);
11571 	}
11572 	/*
11573 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
11574 	 * it's less than ts_recent, drop it.
11575 	 */
11576 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
11577 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
11578 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
11579 			return (ret_val);
11580 	}
11581 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
11582 			      &rack->r_ctl.challenge_ack_ts,
11583 			      &rack->r_ctl.challenge_ack_cnt)) {
11584 		return (ret_val);
11585 	}
11586 	/*
11587 	 * If last ACK falls within this segment's sequence numbers, record
11588 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
11589 	 * from the latest proposal of the tcplw@cray.com list (Braden
11590 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
11591 	 * with our earlier PAWS tests, so this check should be solely
11592 	 * predicated on the sequence space of this segment. 3) That we
11593 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
11594 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
11595 	 * SEG.Len, This modified check allows us to overcome RFC1323's
11596 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
11597 	 * p.869. In such cases, we can still calculate the RTT correctly
11598 	 * when RCV.NXT == Last.ACK.Sent.
11599 	 */
11600 	if ((to->to_flags & TOF_TS) != 0 &&
11601 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
11602 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
11603 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
11604 		tp->ts_recent_age = tcp_ts_getticks();
11605 		tp->ts_recent = to->to_tsval;
11606 	}
11607 	/*
11608 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
11609 	 * is on (half-synchronized state), then queue data for later
11610 	 * processing; else drop segment and return.
11611 	 */
11612 	if ((thflags & TH_ACK) == 0) {
11613 		if (tp->t_flags & TF_NEEDSYN) {
11614 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11615 			    tiwin, thflags, nxt_pkt));
11616 
11617 		} else if (tp->t_flags & TF_ACKNOW) {
11618 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
11619 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
11620 			return (ret_val);
11621 		} else {
11622 			ctf_do_drop(m, NULL);
11623 			return (0);
11624 		}
11625 	}
11626 	/*
11627 	 * Ack processing.
11628 	 */
11629 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) {
11630 		return (ret_val);
11631 	}
11632 	if (sbavail(&so->so_snd)) {
11633 		if (ctf_progress_timeout_check(tp, true)) {
11634 			rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
11635 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11636 			return (1);
11637 		}
11638 	}
11639 	/* State changes only happen in rack_process_data() */
11640 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11641 	    tiwin, thflags, nxt_pkt));
11642 }
11643 
11644 /*
11645  * Return value of 1, the TCB is unlocked and most
11646  * likely gone, return value of 0, the TCP is still
11647  * locked.
11648  */
11649 static int
11650 rack_do_close_wait(struct mbuf *m, struct tcphdr *th, struct socket *so,
11651     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
11652     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
11653 {
11654 	int32_t ret_val = 0;
11655 	struct tcp_rack *rack;
11656 
11657 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11658 	ctf_calc_rwin(so, tp);
11659 	if ((thflags & TH_RST) ||
11660 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
11661 		return (__ctf_process_rst(m, th, so, tp,
11662 					  &rack->r_ctl.challenge_ack_ts,
11663 					  &rack->r_ctl.challenge_ack_cnt));
11664 	/*
11665 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
11666 	 * synchronized state.
11667 	 */
11668 	if (thflags & TH_SYN) {
11669 		ctf_challenge_ack(m, th, tp, iptos, &ret_val);
11670 		return (ret_val);
11671 	}
11672 	/*
11673 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
11674 	 * it's less than ts_recent, drop it.
11675 	 */
11676 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
11677 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
11678 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
11679 			return (ret_val);
11680 	}
11681 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
11682 			      &rack->r_ctl.challenge_ack_ts,
11683 			      &rack->r_ctl.challenge_ack_cnt)) {
11684 		return (ret_val);
11685 	}
11686 	/*
11687 	 * If last ACK falls within this segment's sequence numbers, record
11688 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
11689 	 * from the latest proposal of the tcplw@cray.com list (Braden
11690 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
11691 	 * with our earlier PAWS tests, so this check should be solely
11692 	 * predicated on the sequence space of this segment. 3) That we
11693 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
11694 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
11695 	 * SEG.Len, This modified check allows us to overcome RFC1323's
11696 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
11697 	 * p.869. In such cases, we can still calculate the RTT correctly
11698 	 * when RCV.NXT == Last.ACK.Sent.
11699 	 */
11700 	if ((to->to_flags & TOF_TS) != 0 &&
11701 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
11702 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
11703 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
11704 		tp->ts_recent_age = tcp_ts_getticks();
11705 		tp->ts_recent = to->to_tsval;
11706 	}
11707 	/*
11708 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
11709 	 * is on (half-synchronized state), then queue data for later
11710 	 * processing; else drop segment and return.
11711 	 */
11712 	if ((thflags & TH_ACK) == 0) {
11713 		if (tp->t_flags & TF_NEEDSYN) {
11714 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11715 			    tiwin, thflags, nxt_pkt));
11716 
11717 		} else if (tp->t_flags & TF_ACKNOW) {
11718 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
11719 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
11720 			return (ret_val);
11721 		} else {
11722 			ctf_do_drop(m, NULL);
11723 			return (0);
11724 		}
11725 	}
11726 	/*
11727 	 * Ack processing.
11728 	 */
11729 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) {
11730 		return (ret_val);
11731 	}
11732 	if (sbavail(&so->so_snd)) {
11733 		if (ctf_progress_timeout_check(tp, true)) {
11734 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
11735 						tp, tick, PROGRESS_DROP, __LINE__);
11736 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11737 			return (1);
11738 		}
11739 	}
11740 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11741 	    tiwin, thflags, nxt_pkt));
11742 }
11743 
11744 static int
11745 rack_check_data_after_close(struct mbuf *m,
11746     struct tcpcb *tp, int32_t *tlen, struct tcphdr *th, struct socket *so)
11747 {
11748 	struct tcp_rack *rack;
11749 
11750 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11751 	if (rack->rc_allow_data_af_clo == 0) {
11752 	close_now:
11753 		tcp_log_end_status(tp, TCP_EI_STATUS_DATA_A_CLOSE);
11754 		/* tcp_close will kill the inp pre-log the Reset */
11755 		tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
11756 		tp = tcp_close(tp);
11757 		KMOD_TCPSTAT_INC(tcps_rcvafterclose);
11758 		ctf_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, (*tlen));
11759 		return (1);
11760 	}
11761 	if (sbavail(&so->so_snd) == 0)
11762 		goto close_now;
11763 	/* Ok we allow data that is ignored and a followup reset */
11764 	tcp_log_end_status(tp, TCP_EI_STATUS_DATA_A_CLOSE);
11765 	tp->rcv_nxt = th->th_seq + *tlen;
11766 	tp->t_flags2 |= TF2_DROP_AF_DATA;
11767 	rack->r_wanted_output = 1;
11768 	*tlen = 0;
11769 	return (0);
11770 }
11771 
11772 /*
11773  * Return value of 1, the TCB is unlocked and most
11774  * likely gone, return value of 0, the TCP is still
11775  * locked.
11776  */
11777 static int
11778 rack_do_fin_wait_1(struct mbuf *m, struct tcphdr *th, struct socket *so,
11779     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
11780     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
11781 {
11782 	int32_t ret_val = 0;
11783 	int32_t ourfinisacked = 0;
11784 	struct tcp_rack *rack;
11785 
11786 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11787 	ctf_calc_rwin(so, tp);
11788 
11789 	if ((thflags & TH_RST) ||
11790 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
11791 		return (__ctf_process_rst(m, th, so, tp,
11792 					  &rack->r_ctl.challenge_ack_ts,
11793 					  &rack->r_ctl.challenge_ack_cnt));
11794 	/*
11795 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
11796 	 * synchronized state.
11797 	 */
11798 	if (thflags & TH_SYN) {
11799 		ctf_challenge_ack(m, th, tp, iptos, &ret_val);
11800 		return (ret_val);
11801 	}
11802 	/*
11803 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
11804 	 * it's less than ts_recent, drop it.
11805 	 */
11806 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
11807 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
11808 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
11809 			return (ret_val);
11810 	}
11811 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
11812 			      &rack->r_ctl.challenge_ack_ts,
11813 			      &rack->r_ctl.challenge_ack_cnt)) {
11814 		return (ret_val);
11815 	}
11816 	/*
11817 	 * If new data are received on a connection after the user processes
11818 	 * are gone, then RST the other end.
11819 	 */
11820 	if ((tp->t_flags & TF_CLOSED) && tlen &&
11821 	    rack_check_data_after_close(m, tp, &tlen, th, so))
11822 		return (1);
11823 	/*
11824 	 * If last ACK falls within this segment's sequence numbers, record
11825 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
11826 	 * from the latest proposal of the tcplw@cray.com list (Braden
11827 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
11828 	 * with our earlier PAWS tests, so this check should be solely
11829 	 * predicated on the sequence space of this segment. 3) That we
11830 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
11831 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
11832 	 * SEG.Len, This modified check allows us to overcome RFC1323's
11833 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
11834 	 * p.869. In such cases, we can still calculate the RTT correctly
11835 	 * when RCV.NXT == Last.ACK.Sent.
11836 	 */
11837 	if ((to->to_flags & TOF_TS) != 0 &&
11838 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
11839 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
11840 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
11841 		tp->ts_recent_age = tcp_ts_getticks();
11842 		tp->ts_recent = to->to_tsval;
11843 	}
11844 	/*
11845 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
11846 	 * is on (half-synchronized state), then queue data for later
11847 	 * processing; else drop segment and return.
11848 	 */
11849 	if ((thflags & TH_ACK) == 0) {
11850 		if (tp->t_flags & TF_NEEDSYN) {
11851 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11852 			    tiwin, thflags, nxt_pkt));
11853 		} else if (tp->t_flags & TF_ACKNOW) {
11854 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
11855 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
11856 			return (ret_val);
11857 		} else {
11858 			ctf_do_drop(m, NULL);
11859 			return (0);
11860 		}
11861 	}
11862 	/*
11863 	 * Ack processing.
11864 	 */
11865 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
11866 		return (ret_val);
11867 	}
11868 	if (ourfinisacked) {
11869 		/*
11870 		 * If we can't receive any more data, then closing user can
11871 		 * proceed. Starting the timer is contrary to the
11872 		 * specification, but if we don't get a FIN we'll hang
11873 		 * forever.
11874 		 *
11875 		 * XXXjl: we should release the tp also, and use a
11876 		 * compressed state.
11877 		 */
11878 		if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
11879 			soisdisconnected(so);
11880 			tcp_timer_activate(tp, TT_2MSL,
11881 			    (tcp_fast_finwait2_recycle ?
11882 			    tcp_finwait2_timeout :
11883 			    TP_MAXIDLE(tp)));
11884 		}
11885 		tcp_state_change(tp, TCPS_FIN_WAIT_2);
11886 	}
11887 	if (sbavail(&so->so_snd)) {
11888 		if (ctf_progress_timeout_check(tp, true)) {
11889 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
11890 						tp, tick, PROGRESS_DROP, __LINE__);
11891 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11892 			return (1);
11893 		}
11894 	}
11895 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11896 	    tiwin, thflags, nxt_pkt));
11897 }
11898 
11899 /*
11900  * Return value of 1, the TCB is unlocked and most
11901  * likely gone, return value of 0, the TCP is still
11902  * locked.
11903  */
11904 static int
11905 rack_do_closing(struct mbuf *m, struct tcphdr *th, struct socket *so,
11906     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
11907     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
11908 {
11909 	int32_t ret_val = 0;
11910 	int32_t ourfinisacked = 0;
11911 	struct tcp_rack *rack;
11912 
11913 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11914 	ctf_calc_rwin(so, tp);
11915 
11916 	if ((thflags & TH_RST) ||
11917 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
11918 		return (__ctf_process_rst(m, th, so, tp,
11919 					  &rack->r_ctl.challenge_ack_ts,
11920 					  &rack->r_ctl.challenge_ack_cnt));
11921 	/*
11922 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
11923 	 * synchronized state.
11924 	 */
11925 	if (thflags & TH_SYN) {
11926 		ctf_challenge_ack(m, th, tp, iptos, &ret_val);
11927 		return (ret_val);
11928 	}
11929 	/*
11930 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
11931 	 * it's less than ts_recent, drop it.
11932 	 */
11933 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
11934 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
11935 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
11936 			return (ret_val);
11937 	}
11938 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
11939 			      &rack->r_ctl.challenge_ack_ts,
11940 			      &rack->r_ctl.challenge_ack_cnt)) {
11941 		return (ret_val);
11942 	}
11943 	/*
11944 	 * If new data are received on a connection after the user processes
11945 	 * are gone, then RST the other end.
11946 	 */
11947 	if ((tp->t_flags & TF_CLOSED) && tlen &&
11948 	    rack_check_data_after_close(m, tp, &tlen, th, so))
11949 		return (1);
11950 	/*
11951 	 * If last ACK falls within this segment's sequence numbers, record
11952 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
11953 	 * from the latest proposal of the tcplw@cray.com list (Braden
11954 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
11955 	 * with our earlier PAWS tests, so this check should be solely
11956 	 * predicated on the sequence space of this segment. 3) That we
11957 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
11958 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
11959 	 * SEG.Len, This modified check allows us to overcome RFC1323's
11960 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
11961 	 * p.869. In such cases, we can still calculate the RTT correctly
11962 	 * when RCV.NXT == Last.ACK.Sent.
11963 	 */
11964 	if ((to->to_flags & TOF_TS) != 0 &&
11965 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
11966 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
11967 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
11968 		tp->ts_recent_age = tcp_ts_getticks();
11969 		tp->ts_recent = to->to_tsval;
11970 	}
11971 	/*
11972 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
11973 	 * is on (half-synchronized state), then queue data for later
11974 	 * processing; else drop segment and return.
11975 	 */
11976 	if ((thflags & TH_ACK) == 0) {
11977 		if (tp->t_flags & TF_NEEDSYN) {
11978 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
11979 			    tiwin, thflags, nxt_pkt));
11980 		} else if (tp->t_flags & TF_ACKNOW) {
11981 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
11982 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
11983 			return (ret_val);
11984 		} else {
11985 			ctf_do_drop(m, NULL);
11986 			return (0);
11987 		}
11988 	}
11989 	/*
11990 	 * Ack processing.
11991 	 */
11992 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
11993 		return (ret_val);
11994 	}
11995 	if (ourfinisacked) {
11996 		tcp_twstart(tp);
11997 		m_freem(m);
11998 		return (1);
11999 	}
12000 	if (sbavail(&so->so_snd)) {
12001 		if (ctf_progress_timeout_check(tp, true)) {
12002 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
12003 						tp, tick, PROGRESS_DROP, __LINE__);
12004 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
12005 			return (1);
12006 		}
12007 	}
12008 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12009 	    tiwin, thflags, nxt_pkt));
12010 }
12011 
12012 /*
12013  * Return value of 1, the TCB is unlocked and most
12014  * likely gone, return value of 0, the TCP is still
12015  * locked.
12016  */
12017 static int
12018 rack_do_lastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
12019     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
12020     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
12021 {
12022 	int32_t ret_val = 0;
12023 	int32_t ourfinisacked = 0;
12024 	struct tcp_rack *rack;
12025 
12026 	rack = (struct tcp_rack *)tp->t_fb_ptr;
12027 	ctf_calc_rwin(so, tp);
12028 
12029 	if ((thflags & TH_RST) ||
12030 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
12031 		return (__ctf_process_rst(m, th, so, tp,
12032 					  &rack->r_ctl.challenge_ack_ts,
12033 					  &rack->r_ctl.challenge_ack_cnt));
12034 	/*
12035 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
12036 	 * synchronized state.
12037 	 */
12038 	if (thflags & TH_SYN) {
12039 		ctf_challenge_ack(m, th, tp, iptos, &ret_val);
12040 		return (ret_val);
12041 	}
12042 	/*
12043 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
12044 	 * it's less than ts_recent, drop it.
12045 	 */
12046 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
12047 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
12048 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
12049 			return (ret_val);
12050 	}
12051 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
12052 			      &rack->r_ctl.challenge_ack_ts,
12053 			      &rack->r_ctl.challenge_ack_cnt)) {
12054 		return (ret_val);
12055 	}
12056 	/*
12057 	 * If new data are received on a connection after the user processes
12058 	 * are gone, then RST the other end.
12059 	 */
12060 	if ((tp->t_flags & TF_CLOSED) && tlen &&
12061 	    rack_check_data_after_close(m, tp, &tlen, th, so))
12062 		return (1);
12063 	/*
12064 	 * If last ACK falls within this segment's sequence numbers, record
12065 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
12066 	 * from the latest proposal of the tcplw@cray.com list (Braden
12067 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
12068 	 * with our earlier PAWS tests, so this check should be solely
12069 	 * predicated on the sequence space of this segment. 3) That we
12070 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
12071 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
12072 	 * SEG.Len, This modified check allows us to overcome RFC1323's
12073 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
12074 	 * p.869. In such cases, we can still calculate the RTT correctly
12075 	 * when RCV.NXT == Last.ACK.Sent.
12076 	 */
12077 	if ((to->to_flags & TOF_TS) != 0 &&
12078 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
12079 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
12080 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
12081 		tp->ts_recent_age = tcp_ts_getticks();
12082 		tp->ts_recent = to->to_tsval;
12083 	}
12084 	/*
12085 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
12086 	 * is on (half-synchronized state), then queue data for later
12087 	 * processing; else drop segment and return.
12088 	 */
12089 	if ((thflags & TH_ACK) == 0) {
12090 		if (tp->t_flags & TF_NEEDSYN) {
12091 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12092 			    tiwin, thflags, nxt_pkt));
12093 		} else if (tp->t_flags & TF_ACKNOW) {
12094 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
12095 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
12096 			return (ret_val);
12097 		} else {
12098 			ctf_do_drop(m, NULL);
12099 			return (0);
12100 		}
12101 	}
12102 	/*
12103 	 * case TCPS_LAST_ACK: Ack processing.
12104 	 */
12105 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
12106 		return (ret_val);
12107 	}
12108 	if (ourfinisacked) {
12109 		tp = tcp_close(tp);
12110 		ctf_do_drop(m, tp);
12111 		return (1);
12112 	}
12113 	if (sbavail(&so->so_snd)) {
12114 		if (ctf_progress_timeout_check(tp, true)) {
12115 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
12116 						tp, tick, PROGRESS_DROP, __LINE__);
12117 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
12118 			return (1);
12119 		}
12120 	}
12121 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12122 	    tiwin, thflags, nxt_pkt));
12123 }
12124 
12125 /*
12126  * Return value of 1, the TCB is unlocked and most
12127  * likely gone, return value of 0, the TCP is still
12128  * locked.
12129  */
12130 static int
12131 rack_do_fin_wait_2(struct mbuf *m, struct tcphdr *th, struct socket *so,
12132     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
12133     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
12134 {
12135 	int32_t ret_val = 0;
12136 	int32_t ourfinisacked = 0;
12137 	struct tcp_rack *rack;
12138 
12139 	rack = (struct tcp_rack *)tp->t_fb_ptr;
12140 	ctf_calc_rwin(so, tp);
12141 
12142 	/* Reset receive buffer auto scaling when not in bulk receive mode. */
12143 	if ((thflags & TH_RST) ||
12144 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
12145 		return (__ctf_process_rst(m, th, so, tp,
12146 					  &rack->r_ctl.challenge_ack_ts,
12147 					  &rack->r_ctl.challenge_ack_cnt));
12148 	/*
12149 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
12150 	 * synchronized state.
12151 	 */
12152 	if (thflags & TH_SYN) {
12153 		ctf_challenge_ack(m, th, tp, iptos, &ret_val);
12154 		return (ret_val);
12155 	}
12156 	/*
12157 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
12158 	 * it's less than ts_recent, drop it.
12159 	 */
12160 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
12161 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
12162 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
12163 			return (ret_val);
12164 	}
12165 	if (_ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val,
12166 			      &rack->r_ctl.challenge_ack_ts,
12167 			      &rack->r_ctl.challenge_ack_cnt)) {
12168 		return (ret_val);
12169 	}
12170 	/*
12171 	 * If new data are received on a connection after the user processes
12172 	 * are gone, then RST the other end.
12173 	 */
12174 	if ((tp->t_flags & TF_CLOSED) && tlen &&
12175 	    rack_check_data_after_close(m, tp, &tlen, th, so))
12176 		return (1);
12177 	/*
12178 	 * If last ACK falls within this segment's sequence numbers, record
12179 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
12180 	 * from the latest proposal of the tcplw@cray.com list (Braden
12181 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
12182 	 * with our earlier PAWS tests, so this check should be solely
12183 	 * predicated on the sequence space of this segment. 3) That we
12184 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
12185 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
12186 	 * SEG.Len, This modified check allows us to overcome RFC1323's
12187 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
12188 	 * p.869. In such cases, we can still calculate the RTT correctly
12189 	 * when RCV.NXT == Last.ACK.Sent.
12190 	 */
12191 	if ((to->to_flags & TOF_TS) != 0 &&
12192 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
12193 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
12194 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
12195 		tp->ts_recent_age = tcp_ts_getticks();
12196 		tp->ts_recent = to->to_tsval;
12197 	}
12198 	/*
12199 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
12200 	 * is on (half-synchronized state), then queue data for later
12201 	 * processing; else drop segment and return.
12202 	 */
12203 	if ((thflags & TH_ACK) == 0) {
12204 		if (tp->t_flags & TF_NEEDSYN) {
12205 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12206 			    tiwin, thflags, nxt_pkt));
12207 		} else if (tp->t_flags & TF_ACKNOW) {
12208 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
12209 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
12210 			return (ret_val);
12211 		} else {
12212 			ctf_do_drop(m, NULL);
12213 			return (0);
12214 		}
12215 	}
12216 	/*
12217 	 * Ack processing.
12218 	 */
12219 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
12220 		return (ret_val);
12221 	}
12222 	if (sbavail(&so->so_snd)) {
12223 		if (ctf_progress_timeout_check(tp, true)) {
12224 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
12225 						tp, tick, PROGRESS_DROP, __LINE__);
12226 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
12227 			return (1);
12228 		}
12229 	}
12230 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
12231 	    tiwin, thflags, nxt_pkt));
12232 }
12233 
12234 static void inline
12235 rack_clear_rate_sample(struct tcp_rack *rack)
12236 {
12237 	rack->r_ctl.rack_rs.rs_flags = RACK_RTT_EMPTY;
12238 	rack->r_ctl.rack_rs.rs_rtt_cnt = 0;
12239 	rack->r_ctl.rack_rs.rs_rtt_tot = 0;
12240 }
12241 
12242 static void
12243 rack_set_pace_segments(struct tcpcb *tp, struct tcp_rack *rack, uint32_t line, uint64_t *fill_override)
12244 {
12245 	uint64_t bw_est, rate_wanted;
12246 	int chged = 0;
12247 	uint32_t user_max, orig_min, orig_max;
12248 
12249 	orig_min = rack->r_ctl.rc_pace_min_segs;
12250 	orig_max = rack->r_ctl.rc_pace_max_segs;
12251 	user_max = ctf_fixed_maxseg(tp) * rack->rc_user_set_max_segs;
12252 	if (ctf_fixed_maxseg(tp) != rack->r_ctl.rc_pace_min_segs)
12253 		chged = 1;
12254 	rack->r_ctl.rc_pace_min_segs = ctf_fixed_maxseg(tp);
12255 	if (rack->use_fixed_rate || rack->rc_force_max_seg) {
12256 		if (user_max != rack->r_ctl.rc_pace_max_segs)
12257 			chged = 1;
12258 	}
12259 	if (rack->rc_force_max_seg) {
12260 		rack->r_ctl.rc_pace_max_segs = user_max;
12261 	} else if (rack->use_fixed_rate) {
12262 		bw_est = rack_get_bw(rack);
12263 		if ((rack->r_ctl.crte == NULL) ||
12264 		    (bw_est != rack->r_ctl.crte->rate)) {
12265 			rack->r_ctl.rc_pace_max_segs = user_max;
12266 		} else {
12267 			/* We are pacing right at the hardware rate */
12268 			uint32_t segsiz;
12269 
12270 			segsiz = min(ctf_fixed_maxseg(tp),
12271 				     rack->r_ctl.rc_pace_min_segs);
12272 			rack->r_ctl.rc_pace_max_segs = tcp_get_pacing_burst_size(
12273 				                           tp, bw_est, segsiz, 0,
12274 							   rack->r_ctl.crte, NULL);
12275 		}
12276 	} else if (rack->rc_always_pace) {
12277 		if (rack->r_ctl.gp_bw ||
12278 #ifdef NETFLIX_PEAKRATE
12279 		    rack->rc_tp->t_maxpeakrate ||
12280 #endif
12281 		    rack->r_ctl.init_rate) {
12282 			/* We have a rate of some sort set */
12283 			uint32_t  orig;
12284 
12285 			bw_est = rack_get_bw(rack);
12286 			orig = rack->r_ctl.rc_pace_max_segs;
12287 			if (fill_override)
12288 				rate_wanted = *fill_override;
12289 			else
12290 				rate_wanted = rack_get_output_bw(rack, bw_est, NULL, NULL);
12291 			if (rate_wanted) {
12292 				/* We have something */
12293 				rack->r_ctl.rc_pace_max_segs = rack_get_pacing_len(rack,
12294 										   rate_wanted,
12295 										   ctf_fixed_maxseg(rack->rc_tp));
12296 			} else
12297 				rack->r_ctl.rc_pace_max_segs = rack->r_ctl.rc_pace_min_segs;
12298 			if (orig != rack->r_ctl.rc_pace_max_segs)
12299 				chged = 1;
12300 		} else if ((rack->r_ctl.gp_bw == 0) &&
12301 			   (rack->r_ctl.rc_pace_max_segs == 0)) {
12302 			/*
12303 			 * If we have nothing limit us to bursting
12304 			 * out IW sized pieces.
12305 			 */
12306 			chged = 1;
12307 			rack->r_ctl.rc_pace_max_segs = rc_init_window(rack);
12308 		}
12309 	}
12310 	if (rack->r_ctl.rc_pace_max_segs > PACE_MAX_IP_BYTES) {
12311 		chged = 1;
12312 		rack->r_ctl.rc_pace_max_segs = PACE_MAX_IP_BYTES;
12313 	}
12314 	if (chged)
12315 		rack_log_type_pacing_sizes(tp, rack, orig_min, orig_max, line, 2);
12316 }
12317 
12318 
12319 static void
12320 rack_init_fsb_block(struct tcpcb *tp, struct tcp_rack *rack)
12321 {
12322 #ifdef INET6
12323 	struct ip6_hdr *ip6 = NULL;
12324 #endif
12325 #ifdef INET
12326 	struct ip *ip = NULL;
12327 #endif
12328 	struct udphdr *udp = NULL;
12329 
12330 	/* Ok lets fill in the fast block, it can only be used with no IP options! */
12331 #ifdef INET6
12332 	if (rack->r_is_v6) {
12333 		rack->r_ctl.fsb.tcp_ip_hdr_len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
12334 		ip6 = (struct ip6_hdr *)rack->r_ctl.fsb.tcp_ip_hdr;
12335 		if (tp->t_port) {
12336 			rack->r_ctl.fsb.tcp_ip_hdr_len += sizeof(struct udphdr);
12337 			udp = (struct udphdr *)((caddr_t)ip6 + sizeof(struct ip6_hdr));
12338 			udp->uh_sport = htons(V_tcp_udp_tunneling_port);
12339 			udp->uh_dport = tp->t_port;
12340 			rack->r_ctl.fsb.udp = udp;
12341 			rack->r_ctl.fsb.th = (struct tcphdr *)(udp + 1);
12342 		} else
12343 		{
12344 			rack->r_ctl.fsb.th = (struct tcphdr *)(ip6 + 1);
12345 			rack->r_ctl.fsb.udp = NULL;
12346 		}
12347 		tcpip_fillheaders(rack->rc_inp,
12348 				  tp->t_port,
12349 				  ip6, rack->r_ctl.fsb.th);
12350 	} else
12351 #endif				/* INET6 */
12352 #ifdef INET
12353 	{
12354 		rack->r_ctl.fsb.tcp_ip_hdr_len = sizeof(struct tcpiphdr);
12355 		ip = (struct ip *)rack->r_ctl.fsb.tcp_ip_hdr;
12356 		if (tp->t_port) {
12357 			rack->r_ctl.fsb.tcp_ip_hdr_len += sizeof(struct udphdr);
12358 			udp = (struct udphdr *)((caddr_t)ip + sizeof(struct ip));
12359 			udp->uh_sport = htons(V_tcp_udp_tunneling_port);
12360 			udp->uh_dport = tp->t_port;
12361 			rack->r_ctl.fsb.udp = udp;
12362 			rack->r_ctl.fsb.th = (struct tcphdr *)(udp + 1);
12363 		} else
12364 		{
12365 			rack->r_ctl.fsb.udp = NULL;
12366 			rack->r_ctl.fsb.th = (struct tcphdr *)(ip + 1);
12367 		}
12368 		tcpip_fillheaders(rack->rc_inp,
12369 				  tp->t_port,
12370 				  ip, rack->r_ctl.fsb.th);
12371 	}
12372 #endif
12373 	rack->r_fsb_inited = 1;
12374 }
12375 
12376 static int
12377 rack_init_fsb(struct tcpcb *tp, struct tcp_rack *rack)
12378 {
12379 	/*
12380 	 * Allocate the larger of spaces V6 if available else just
12381 	 * V4 and include udphdr (overbook)
12382 	 */
12383 #ifdef INET6
12384 	rack->r_ctl.fsb.tcp_ip_hdr_len = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + sizeof(struct udphdr);
12385 #else
12386 	rack->r_ctl.fsb.tcp_ip_hdr_len = sizeof(struct tcpiphdr) + sizeof(struct udphdr);
12387 #endif
12388 	rack->r_ctl.fsb.tcp_ip_hdr = malloc(rack->r_ctl.fsb.tcp_ip_hdr_len,
12389 					    M_TCPFSB, M_NOWAIT|M_ZERO);
12390 	if (rack->r_ctl.fsb.tcp_ip_hdr == NULL) {
12391 		return (ENOMEM);
12392 	}
12393 	rack->r_fsb_inited = 0;
12394 	return (0);
12395 }
12396 
12397 static int
12398 rack_init(struct tcpcb *tp)
12399 {
12400 	struct inpcb *inp = tptoinpcb(tp);
12401 	struct tcp_rack *rack = NULL;
12402 #ifdef INVARIANTS
12403 	struct rack_sendmap *insret;
12404 #endif
12405 	uint32_t iwin, snt, us_cts;
12406 	int err;
12407 
12408 	tp->t_fb_ptr = uma_zalloc(rack_pcb_zone, M_NOWAIT);
12409 	if (tp->t_fb_ptr == NULL) {
12410 		/*
12411 		 * We need to allocate memory but cant. The INP and INP_INFO
12412 		 * locks and they are recursive (happens during setup. So a
12413 		 * scheme to drop the locks fails :(
12414 		 *
12415 		 */
12416 		return (ENOMEM);
12417 	}
12418 	memset(tp->t_fb_ptr, 0, sizeof(struct tcp_rack));
12419 
12420 	rack = (struct tcp_rack *)tp->t_fb_ptr;
12421 	RB_INIT(&rack->r_ctl.rc_mtree);
12422 	TAILQ_INIT(&rack->r_ctl.rc_free);
12423 	TAILQ_INIT(&rack->r_ctl.rc_tmap);
12424 	rack->rc_tp = tp;
12425 	rack->rc_inp = inp;
12426 	/* Set the flag */
12427 	rack->r_is_v6 = (inp->inp_vflag & INP_IPV6) != 0;
12428 	/* Probably not needed but lets be sure */
12429 	rack_clear_rate_sample(rack);
12430 	/*
12431 	 * Save off the default values, socket options will poke
12432 	 * at these if pacing is not on or we have not yet
12433 	 * reached where pacing is on (gp_ready/fixed enabled).
12434 	 * When they get set into the CC module (when gp_ready
12435 	 * is enabled or we enable fixed) then we will set these
12436 	 * values into the CC and place in here the old values
12437 	 * so we have a restoral. Then we will set the flag
12438 	 * rc_pacing_cc_set. That way whenever we turn off pacing
12439 	 * or switch off this stack, we will know to go restore
12440 	 * the saved values.
12441 	 */
12442 	rack->r_ctl.rc_saved_beta.beta = V_newreno_beta_ecn;
12443 	rack->r_ctl.rc_saved_beta.beta_ecn = V_newreno_beta_ecn;
12444 	/* We want abe like behavior as well */
12445 	rack->r_ctl.rc_saved_beta.newreno_flags |= CC_NEWRENO_BETA_ECN_ENABLED;
12446 	rack->r_ctl.rc_reorder_fade = rack_reorder_fade;
12447 	rack->rc_allow_data_af_clo = rack_ignore_data_after_close;
12448 	rack->r_ctl.rc_tlp_threshold = rack_tlp_thresh;
12449 	rack->r_ctl.roundends = tp->snd_max;
12450 	if (use_rack_rr)
12451 		rack->use_rack_rr = 1;
12452 	if (V_tcp_delack_enabled)
12453 		tp->t_delayed_ack = 1;
12454 	else
12455 		tp->t_delayed_ack = 0;
12456 #ifdef TCP_ACCOUNTING
12457 	if (rack_tcp_accounting) {
12458 		tp->t_flags2 |= TF2_TCP_ACCOUNTING;
12459 	}
12460 #endif
12461 	if (rack_enable_shared_cwnd)
12462 		rack->rack_enable_scwnd = 1;
12463 	rack->rc_user_set_max_segs = rack_hptsi_segments;
12464 	rack->rc_force_max_seg = 0;
12465 	if (rack_use_imac_dack)
12466 		rack->rc_dack_mode = 1;
12467 	TAILQ_INIT(&rack->r_ctl.opt_list);
12468 	rack->r_ctl.rc_reorder_shift = rack_reorder_thresh;
12469 	rack->r_ctl.rc_pkt_delay = rack_pkt_delay;
12470 	rack->r_ctl.rc_tlp_cwnd_reduce = rack_lower_cwnd_at_tlp;
12471 	rack->r_ctl.rc_lowest_us_rtt = 0xffffffff;
12472 	rack->r_ctl.rc_highest_us_rtt = 0;
12473 	rack->r_ctl.bw_rate_cap = rack_bw_rate_cap;
12474 	rack->r_ctl.timer_slop = TICKS_2_USEC(tcp_rexmit_slop);
12475 	if (rack_use_cmp_acks)
12476 		rack->r_use_cmp_ack = 1;
12477 	if (rack_disable_prr)
12478 		rack->rack_no_prr = 1;
12479 	if (rack_gp_no_rec_chg)
12480 		rack->rc_gp_no_rec_chg = 1;
12481 	if (rack_pace_every_seg && tcp_can_enable_pacing()) {
12482 		rack->rc_always_pace = 1;
12483 		if (rack->use_fixed_rate || rack->gp_ready)
12484 			rack_set_cc_pacing(rack);
12485 	} else
12486 		rack->rc_always_pace = 0;
12487 	if (rack_enable_mqueue_for_nonpaced || rack->r_use_cmp_ack)
12488 		rack->r_mbuf_queue = 1;
12489 	else
12490 		rack->r_mbuf_queue = 0;
12491 	if  (rack->r_mbuf_queue || rack->rc_always_pace || rack->r_use_cmp_ack)
12492 		inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
12493 	else
12494 		inp->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
12495 	rack_set_pace_segments(tp, rack, __LINE__, NULL);
12496 	if (rack_limits_scwnd)
12497 		rack->r_limit_scw = 1;
12498 	else
12499 		rack->r_limit_scw = 0;
12500 	rack->rc_labc = V_tcp_abc_l_var;
12501 	rack->r_ctl.rc_high_rwnd = tp->snd_wnd;
12502 	rack->r_ctl.cwnd_to_use = tp->snd_cwnd;
12503 	rack->r_ctl.rc_rate_sample_method = rack_rate_sample_method;
12504 	rack->rack_tlp_threshold_use = rack_tlp_threshold_use;
12505 	rack->r_ctl.rc_prr_sendalot = rack_send_a_lot_in_prr;
12506 	rack->r_ctl.rc_min_to = rack_min_to;
12507 	microuptime(&rack->r_ctl.act_rcv_time);
12508 	rack->r_ctl.rc_last_time_decay = rack->r_ctl.act_rcv_time;
12509 	rack->rc_init_win = rack_default_init_window;
12510 	rack->r_ctl.rack_per_of_gp_ss = rack_per_of_gp_ss;
12511 	if (rack_hw_up_only)
12512 		rack->r_up_only = 1;
12513 	if (rack_do_dyn_mul) {
12514 		/* When dynamic adjustment is on CA needs to start at 100% */
12515 		rack->rc_gp_dyn_mul = 1;
12516 		if (rack_do_dyn_mul >= 100)
12517 			rack->r_ctl.rack_per_of_gp_ca = rack_do_dyn_mul;
12518 	} else
12519 		rack->r_ctl.rack_per_of_gp_ca = rack_per_of_gp_ca;
12520 	rack->r_ctl.rack_per_of_gp_rec = rack_per_of_gp_rec;
12521 	rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt;
12522 	rack->r_ctl.rc_tlp_rxt_last_time = tcp_tv_to_mssectick(&rack->r_ctl.act_rcv_time);
12523 	setup_time_filter_small(&rack->r_ctl.rc_gp_min_rtt, FILTER_TYPE_MIN,
12524 				rack_probertt_filter_life);
12525 	us_cts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
12526 	rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
12527 	rack->r_ctl.rc_time_of_last_probertt = us_cts;
12528 	rack->r_ctl.challenge_ack_ts = tcp_ts_getticks();
12529 	rack->r_ctl.rc_time_probertt_starts = 0;
12530 	if (rack_dsack_std_based & 0x1) {
12531 		/* Basically this means all rack timers are at least (srtt + 1/4 srtt) */
12532 		rack->rc_rack_tmr_std_based = 1;
12533 	}
12534 	if (rack_dsack_std_based & 0x2) {
12535 		/* Basically this means  rack timers are extended based on dsack by up to (2 * srtt) */
12536 		rack->rc_rack_use_dsack = 1;
12537 	}
12538 	/* We require at least one measurement, even if the sysctl is 0 */
12539 	if (rack_req_measurements)
12540 		rack->r_ctl.req_measurements = rack_req_measurements;
12541 	else
12542 		rack->r_ctl.req_measurements = 1;
12543 	if (rack_enable_hw_pacing)
12544 		rack->rack_hdw_pace_ena = 1;
12545 	if (rack_hw_rate_caps)
12546 		rack->r_rack_hw_rate_caps = 1;
12547 	/* Do we force on detection? */
12548 #ifdef NETFLIX_EXP_DETECTION
12549 	if (tcp_force_detection)
12550 		rack->do_detection = 1;
12551 	else
12552 #endif
12553 		rack->do_detection = 0;
12554 	if (rack_non_rxt_use_cr)
12555 		rack->rack_rec_nonrxt_use_cr = 1;
12556 	err = rack_init_fsb(tp, rack);
12557 	if (err) {
12558 		uma_zfree(rack_pcb_zone, tp->t_fb_ptr);
12559 		tp->t_fb_ptr = NULL;
12560 		return (err);
12561 	}
12562 	if (tp->snd_una != tp->snd_max) {
12563 		/* Create a send map for the current outstanding data */
12564 		struct rack_sendmap *rsm;
12565 
12566 		rsm = rack_alloc(rack);
12567 		if (rsm == NULL) {
12568 			uma_zfree(rack_pcb_zone, tp->t_fb_ptr);
12569 			tp->t_fb_ptr = NULL;
12570 			return (ENOMEM);
12571 		}
12572 		rsm->r_no_rtt_allowed = 1;
12573 		rsm->r_tim_lastsent[0] = rack_to_usec_ts(&rack->r_ctl.act_rcv_time);
12574 		rsm->r_rtr_cnt = 1;
12575 		rsm->r_rtr_bytes = 0;
12576 		if (tp->t_flags & TF_SENTFIN)
12577 			rsm->r_flags |= RACK_HAS_FIN;
12578 		if ((tp->snd_una == tp->iss) &&
12579 		    !TCPS_HAVEESTABLISHED(tp->t_state))
12580 			rsm->r_flags |= RACK_HAS_SYN;
12581 		rsm->r_start = tp->snd_una;
12582 		rsm->r_end = tp->snd_max;
12583 		rsm->r_dupack = 0;
12584 		if (rack->rc_inp->inp_socket->so_snd.sb_mb != NULL) {
12585 			rsm->m = sbsndmbuf(&rack->rc_inp->inp_socket->so_snd, 0, &rsm->soff);
12586 			if (rsm->m)
12587 				rsm->orig_m_len = rsm->m->m_len;
12588 			else
12589 				rsm->orig_m_len = 0;
12590 		} else {
12591 			/*
12592 			 * This can happen if we have a stand-alone FIN or
12593 			 *  SYN.
12594 			 */
12595 			rsm->m = NULL;
12596 			rsm->orig_m_len = 0;
12597 			rsm->soff = 0;
12598 		}
12599 #ifndef INVARIANTS
12600 		(void)RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
12601 #else
12602 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
12603 		if (insret != NULL) {
12604 			panic("Insert in rb tree fails ret:%p rack:%p rsm:%p",
12605 			      insret, rack, rsm);
12606 		}
12607 #endif
12608 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext);
12609 		rsm->r_in_tmap = 1;
12610 	}
12611 	/*
12612 	 * Timers in Rack are kept in microseconds so lets
12613 	 * convert any initial incoming variables
12614 	 * from ticks into usecs. Note that we
12615 	 * also change the values of t_srtt and t_rttvar, if
12616 	 * they are non-zero. They are kept with a 5
12617 	 * bit decimal so we have to carefully convert
12618 	 * these to get the full precision.
12619 	 */
12620 	rack_convert_rtts(tp);
12621 	tp->t_rttlow = TICKS_2_USEC(tp->t_rttlow);
12622 	if (rack_do_hystart) {
12623 		tp->t_ccv.flags |= CCF_HYSTART_ALLOWED;
12624 		if (rack_do_hystart > 1)
12625 			tp->t_ccv.flags |= CCF_HYSTART_CAN_SH_CWND;
12626 		if (rack_do_hystart > 2)
12627 			tp->t_ccv.flags |= CCF_HYSTART_CONS_SSTH;
12628 	}
12629 	if (rack_def_profile)
12630 		rack_set_profile(rack, rack_def_profile);
12631 	/* Cancel the GP measurement in progress */
12632 	tp->t_flags &= ~TF_GPUTINPROG;
12633 	if (SEQ_GT(tp->snd_max, tp->iss))
12634 		snt = tp->snd_max - tp->iss;
12635 	else
12636 		snt = 0;
12637 	iwin = rc_init_window(rack);
12638 	if (snt < iwin) {
12639 		/* We are not past the initial window
12640 		 * so we need to make sure cwnd is
12641 		 * correct.
12642 		 */
12643 		if (tp->snd_cwnd < iwin)
12644 			tp->snd_cwnd = iwin;
12645 		/*
12646 		 * If we are within the initial window
12647 		 * we want ssthresh to be unlimited. Setting
12648 		 * it to the rwnd (which the default stack does
12649 		 * and older racks) is not really a good idea
12650 		 * since we want to be in SS and grow both the
12651 		 * cwnd and the rwnd (via dynamic rwnd growth). If
12652 		 * we set it to the rwnd then as the peer grows its
12653 		 * rwnd we will be stuck in CA and never hit SS.
12654 		 *
12655 		 * Its far better to raise it up high (this takes the
12656 		 * risk that there as been a loss already, probably
12657 		 * we should have an indicator in all stacks of loss
12658 		 * but we don't), but considering the normal use this
12659 		 * is a risk worth taking. The consequences of not
12660 		 * hitting SS are far worse than going one more time
12661 		 * into it early on (before we have sent even a IW).
12662 		 * It is highly unlikely that we will have had a loss
12663 		 * before getting the IW out.
12664 		 */
12665 		tp->snd_ssthresh = 0xffffffff;
12666 	}
12667 	rack_stop_all_timers(tp);
12668 	/* Lets setup the fsb block */
12669 	rack_start_hpts_timer(rack, tp, tcp_get_usecs(NULL), 0, 0, 0);
12670 	rack_log_rtt_shrinks(rack,  us_cts,  tp->t_rxtcur,
12671 			     __LINE__, RACK_RTTS_INIT);
12672 	return (0);
12673 }
12674 
12675 static int
12676 rack_handoff_ok(struct tcpcb *tp)
12677 {
12678 	if ((tp->t_state == TCPS_CLOSED) ||
12679 	    (tp->t_state == TCPS_LISTEN)) {
12680 		/* Sure no problem though it may not stick */
12681 		return (0);
12682 	}
12683 	if ((tp->t_state == TCPS_SYN_SENT) ||
12684 	    (tp->t_state == TCPS_SYN_RECEIVED)) {
12685 		/*
12686 		 * We really don't know if you support sack,
12687 		 * you have to get to ESTAB or beyond to tell.
12688 		 */
12689 		return (EAGAIN);
12690 	}
12691 	if ((tp->t_flags & TF_SENTFIN) && ((tp->snd_max - tp->snd_una) > 1)) {
12692 		/*
12693 		 * Rack will only send a FIN after all data is acknowledged.
12694 		 * So in this case we have more data outstanding. We can't
12695 		 * switch stacks until either all data and only the FIN
12696 		 * is left (in which case rack_init() now knows how
12697 		 * to deal with that) <or> all is acknowledged and we
12698 		 * are only left with incoming data, though why you
12699 		 * would want to switch to rack after all data is acknowledged
12700 		 * I have no idea (rrs)!
12701 		 */
12702 		return (EAGAIN);
12703 	}
12704 	if ((tp->t_flags & TF_SACK_PERMIT) || rack_sack_not_required){
12705 		return (0);
12706 	}
12707 	/*
12708 	 * If we reach here we don't do SACK on this connection so we can
12709 	 * never do rack.
12710 	 */
12711 	return (EINVAL);
12712 }
12713 
12714 
12715 static void
12716 rack_fini(struct tcpcb *tp, int32_t tcb_is_purged)
12717 {
12718 	struct inpcb *inp = tptoinpcb(tp);
12719 
12720 	if (tp->t_fb_ptr) {
12721 		struct tcp_rack *rack;
12722 		struct rack_sendmap *rsm, *nrsm;
12723 #ifdef INVARIANTS
12724 		struct rack_sendmap *rm;
12725 #endif
12726 
12727 		rack = (struct tcp_rack *)tp->t_fb_ptr;
12728 		if (tp->t_in_pkt) {
12729 			/*
12730 			 * It is unsafe to process the packets since a
12731 			 * reset may be lurking in them (its rare but it
12732 			 * can occur). If we were to find a RST, then we
12733 			 * would end up dropping the connection and the
12734 			 * INP lock, so when we return the caller (tcp_usrreq)
12735 			 * will blow up when it trys to unlock the inp.
12736 			 */
12737 			struct mbuf *save, *m;
12738 
12739 			m = tp->t_in_pkt;
12740 			tp->t_in_pkt = NULL;
12741 			tp->t_tail_pkt = NULL;
12742 			while (m) {
12743 				save = m->m_nextpkt;
12744 				m->m_nextpkt = NULL;
12745 				m_freem(m);
12746 				m = save;
12747 			}
12748 		}
12749 		tp->t_flags &= ~TF_FORCEDATA;
12750 #ifdef NETFLIX_SHARED_CWND
12751 		if (rack->r_ctl.rc_scw) {
12752 			uint32_t limit;
12753 
12754 			if (rack->r_limit_scw)
12755 				limit = max(1, rack->r_ctl.rc_lowest_us_rtt);
12756 			else
12757 				limit = 0;
12758 			tcp_shared_cwnd_free_full(tp, rack->r_ctl.rc_scw,
12759 						  rack->r_ctl.rc_scw_index,
12760 						  limit);
12761 			rack->r_ctl.rc_scw = NULL;
12762 		}
12763 #endif
12764 		if (rack->r_ctl.fsb.tcp_ip_hdr) {
12765 			free(rack->r_ctl.fsb.tcp_ip_hdr, M_TCPFSB);
12766 			rack->r_ctl.fsb.tcp_ip_hdr = NULL;
12767 			rack->r_ctl.fsb.th = NULL;
12768 		}
12769 		/* Convert back to ticks, with  */
12770 		if (tp->t_srtt > 1) {
12771 			uint32_t val, frac;
12772 
12773 			val = USEC_2_TICKS(tp->t_srtt);
12774 			frac = tp->t_srtt % (HPTS_USEC_IN_SEC / hz);
12775 			tp->t_srtt = val << TCP_RTT_SHIFT;
12776 			/*
12777 			 * frac is the fractional part here is left
12778 			 * over from converting to hz and shifting.
12779 			 * We need to convert this to the 5 bit
12780 			 * remainder.
12781 			 */
12782 			if (frac) {
12783 				if (hz == 1000) {
12784 					frac = (((uint64_t)frac *  (uint64_t)TCP_RTT_SCALE) / (uint64_t)HPTS_USEC_IN_MSEC);
12785 				} else {
12786 					frac = (((uint64_t)frac * (uint64_t)(hz) * (uint64_t)TCP_RTT_SCALE) /(uint64_t)HPTS_USEC_IN_SEC);
12787 				}
12788 				tp->t_srtt += frac;
12789 			}
12790 		}
12791 		if (tp->t_rttvar) {
12792 			uint32_t val, frac;
12793 
12794 			val = USEC_2_TICKS(tp->t_rttvar);
12795 			frac = tp->t_srtt % (HPTS_USEC_IN_SEC / hz);
12796 			tp->t_rttvar = val <<  TCP_RTTVAR_SHIFT;
12797 			/*
12798 			 * frac is the fractional part here is left
12799 			 * over from converting to hz and shifting.
12800 			 * We need to convert this to the 5 bit
12801 			 * remainder.
12802 			 */
12803 			if (frac) {
12804 				if (hz == 1000) {
12805 					frac = (((uint64_t)frac *  (uint64_t)TCP_RTT_SCALE) / (uint64_t)HPTS_USEC_IN_MSEC);
12806 				} else {
12807 					frac = (((uint64_t)frac * (uint64_t)(hz) * (uint64_t)TCP_RTT_SCALE) /(uint64_t)HPTS_USEC_IN_SEC);
12808 				}
12809 				tp->t_rttvar += frac;
12810 			}
12811 		}
12812 		tp->t_rxtcur = USEC_2_TICKS(tp->t_rxtcur);
12813 		tp->t_rttlow = USEC_2_TICKS(tp->t_rttlow);
12814 		if (rack->rc_always_pace) {
12815 			tcp_decrement_paced_conn();
12816 			rack_undo_cc_pacing(rack);
12817 			rack->rc_always_pace = 0;
12818 		}
12819 		/* Clean up any options if they were not applied */
12820 		while (!TAILQ_EMPTY(&rack->r_ctl.opt_list)) {
12821 			struct deferred_opt_list *dol;
12822 
12823 			dol = TAILQ_FIRST(&rack->r_ctl.opt_list);
12824 			TAILQ_REMOVE(&rack->r_ctl.opt_list, dol, next);
12825 			free(dol, M_TCPDO);
12826 		}
12827 		/* rack does not use force data but other stacks may clear it */
12828 		if (rack->r_ctl.crte != NULL) {
12829 			tcp_rel_pacing_rate(rack->r_ctl.crte, tp);
12830 			rack->rack_hdrw_pacing = 0;
12831 			rack->r_ctl.crte = NULL;
12832 		}
12833 #ifdef TCP_BLACKBOX
12834 		tcp_log_flowend(tp);
12835 #endif
12836 		RB_FOREACH_SAFE(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm) {
12837 #ifndef INVARIANTS
12838 			(void)RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
12839 #else
12840 			rm = RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
12841 			if (rm != rsm) {
12842 				panic("At fini, rack:%p rsm:%p rm:%p",
12843 				      rack, rsm, rm);
12844 			}
12845 #endif
12846 			uma_zfree(rack_zone, rsm);
12847 		}
12848 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
12849 		while (rsm) {
12850 			TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_tnext);
12851 			uma_zfree(rack_zone, rsm);
12852 			rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
12853 		}
12854 		rack->rc_free_cnt = 0;
12855 		uma_zfree(rack_pcb_zone, tp->t_fb_ptr);
12856 		tp->t_fb_ptr = NULL;
12857 	}
12858 	inp->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
12859 	inp->inp_flags2 &= ~INP_MBUF_QUEUE_READY;
12860 	inp->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
12861 	inp->inp_flags2 &= ~INP_MBUF_ACKCMP;
12862 	/* Cancel the GP measurement in progress */
12863 	tp->t_flags &= ~TF_GPUTINPROG;
12864 	inp->inp_flags2 &= ~INP_MBUF_L_ACKS;
12865 	/* Make sure snd_nxt is correctly set */
12866 	tp->snd_nxt = tp->snd_max;
12867 }
12868 
12869 static void
12870 rack_set_state(struct tcpcb *tp, struct tcp_rack *rack)
12871 {
12872 	if ((rack->r_state == TCPS_CLOSED) && (tp->t_state != TCPS_CLOSED)) {
12873 		rack->r_is_v6 = (tptoinpcb(tp)->inp_vflag & INP_IPV6) != 0;
12874 	}
12875 	switch (tp->t_state) {
12876 	case TCPS_SYN_SENT:
12877 		rack->r_state = TCPS_SYN_SENT;
12878 		rack->r_substate = rack_do_syn_sent;
12879 		break;
12880 	case TCPS_SYN_RECEIVED:
12881 		rack->r_state = TCPS_SYN_RECEIVED;
12882 		rack->r_substate = rack_do_syn_recv;
12883 		break;
12884 	case TCPS_ESTABLISHED:
12885 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
12886 		rack->r_state = TCPS_ESTABLISHED;
12887 		rack->r_substate = rack_do_established;
12888 		break;
12889 	case TCPS_CLOSE_WAIT:
12890 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
12891 		rack->r_state = TCPS_CLOSE_WAIT;
12892 		rack->r_substate = rack_do_close_wait;
12893 		break;
12894 	case TCPS_FIN_WAIT_1:
12895 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
12896 		rack->r_state = TCPS_FIN_WAIT_1;
12897 		rack->r_substate = rack_do_fin_wait_1;
12898 		break;
12899 	case TCPS_CLOSING:
12900 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
12901 		rack->r_state = TCPS_CLOSING;
12902 		rack->r_substate = rack_do_closing;
12903 		break;
12904 	case TCPS_LAST_ACK:
12905 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
12906 		rack->r_state = TCPS_LAST_ACK;
12907 		rack->r_substate = rack_do_lastack;
12908 		break;
12909 	case TCPS_FIN_WAIT_2:
12910 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
12911 		rack->r_state = TCPS_FIN_WAIT_2;
12912 		rack->r_substate = rack_do_fin_wait_2;
12913 		break;
12914 	case TCPS_LISTEN:
12915 	case TCPS_CLOSED:
12916 	case TCPS_TIME_WAIT:
12917 	default:
12918 		break;
12919 	};
12920 	if (rack->r_use_cmp_ack && TCPS_HAVEESTABLISHED(tp->t_state))
12921 		rack->rc_inp->inp_flags2 |= INP_MBUF_ACKCMP;
12922 
12923 }
12924 
12925 static void
12926 rack_timer_audit(struct tcpcb *tp, struct tcp_rack *rack, struct sockbuf *sb)
12927 {
12928 	/*
12929 	 * We received an ack, and then did not
12930 	 * call send or were bounced out due to the
12931 	 * hpts was running. Now a timer is up as well, is
12932 	 * it the right timer?
12933 	 */
12934 	struct rack_sendmap *rsm;
12935 	int tmr_up;
12936 
12937 	tmr_up = rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK;
12938 	if (rack->rc_in_persist && (tmr_up == PACE_TMR_PERSIT))
12939 		return;
12940 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
12941 	if (((rsm == NULL) || (tp->t_state < TCPS_ESTABLISHED)) &&
12942 	    (tmr_up == PACE_TMR_RXT)) {
12943 		/* Should be an RXT */
12944 		return;
12945 	}
12946 	if (rsm == NULL) {
12947 		/* Nothing outstanding? */
12948 		if (tp->t_flags & TF_DELACK) {
12949 			if (tmr_up == PACE_TMR_DELACK)
12950 				/* We are supposed to have delayed ack up and we do */
12951 				return;
12952 		} else if (sbavail(&tptosocket(tp)->so_snd) && (tmr_up == PACE_TMR_RXT)) {
12953 			/*
12954 			 * if we hit enobufs then we would expect the possibility
12955 			 * of nothing outstanding and the RXT up (and the hptsi timer).
12956 			 */
12957 			return;
12958 		} else if (((V_tcp_always_keepalive ||
12959 			     rack->rc_inp->inp_socket->so_options & SO_KEEPALIVE) &&
12960 			    (tp->t_state <= TCPS_CLOSING)) &&
12961 			   (tmr_up == PACE_TMR_KEEP) &&
12962 			   (tp->snd_max == tp->snd_una)) {
12963 			/* We should have keep alive up and we do */
12964 			return;
12965 		}
12966 	}
12967 	if (SEQ_GT(tp->snd_max, tp->snd_una) &&
12968 		   ((tmr_up == PACE_TMR_TLP) ||
12969 		    (tmr_up == PACE_TMR_RACK) ||
12970 		    (tmr_up == PACE_TMR_RXT))) {
12971 		/*
12972 		 * Either a Rack, TLP or RXT is fine if  we
12973 		 * have outstanding data.
12974 		 */
12975 		return;
12976 	} else if (tmr_up == PACE_TMR_DELACK) {
12977 		/*
12978 		 * If the delayed ack was going to go off
12979 		 * before the rtx/tlp/rack timer were going to
12980 		 * expire, then that would be the timer in control.
12981 		 * Note we don't check the time here trusting the
12982 		 * code is correct.
12983 		 */
12984 		return;
12985 	}
12986 	/*
12987 	 * Ok the timer originally started is not what we want now.
12988 	 * We will force the hpts to be stopped if any, and restart
12989 	 * with the slot set to what was in the saved slot.
12990 	 */
12991 	if (tcp_in_hpts(rack->rc_inp)) {
12992 		if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
12993 			uint32_t us_cts;
12994 
12995 			us_cts = tcp_get_usecs(NULL);
12996 			if (TSTMP_GT(rack->r_ctl.rc_last_output_to, us_cts)) {
12997 				rack->r_early = 1;
12998 				rack->r_ctl.rc_agg_early += (rack->r_ctl.rc_last_output_to - us_cts);
12999 			}
13000 			rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
13001 		}
13002 		tcp_hpts_remove(rack->rc_inp);
13003 	}
13004 	rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
13005 	rack_start_hpts_timer(rack, tp, tcp_get_usecs(NULL), 0, 0, 0);
13006 }
13007 
13008 
13009 static void
13010 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)
13011 {
13012 	if ((SEQ_LT(tp->snd_wl1, seq) ||
13013 	    (tp->snd_wl1 == seq && (SEQ_LT(tp->snd_wl2, ack) ||
13014 	    (tp->snd_wl2 == ack && tiwin > tp->snd_wnd))))) {
13015 		/* keep track of pure window updates */
13016 		if ((tp->snd_wl2 == ack) && (tiwin > tp->snd_wnd))
13017 			KMOD_TCPSTAT_INC(tcps_rcvwinupd);
13018 		tp->snd_wnd = tiwin;
13019 		rack_validate_fo_sendwin_up(tp, rack);
13020 		tp->snd_wl1 = seq;
13021 		tp->snd_wl2 = ack;
13022 		if (tp->snd_wnd > tp->max_sndwnd)
13023 			tp->max_sndwnd = tp->snd_wnd;
13024 	    rack->r_wanted_output = 1;
13025 	} else if ((tp->snd_wl2 == ack) && (tiwin < tp->snd_wnd)) {
13026 		tp->snd_wnd = tiwin;
13027 		rack_validate_fo_sendwin_up(tp, rack);
13028 		tp->snd_wl1 = seq;
13029 		tp->snd_wl2 = ack;
13030 	} else {
13031 		/* Not a valid win update */
13032 		return;
13033 	}
13034 	/* Do we exit persists? */
13035 	if ((rack->rc_in_persist != 0) &&
13036 	    (tp->snd_wnd >= min((rack->r_ctl.rc_high_rwnd/2),
13037 				rack->r_ctl.rc_pace_min_segs))) {
13038 		rack_exit_persist(tp, rack, cts);
13039 	}
13040 	/* Do we enter persists? */
13041 	if ((rack->rc_in_persist == 0) &&
13042 	    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), rack->r_ctl.rc_pace_min_segs)) &&
13043 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
13044 	    ((tp->snd_max == tp->snd_una) || rack->rc_has_collapsed) &&
13045 	    sbavail(&tptosocket(tp)->so_snd) &&
13046 	    (sbavail(&tptosocket(tp)->so_snd) > tp->snd_wnd)) {
13047 		/*
13048 		 * Here the rwnd is less than
13049 		 * the pacing size, we are established,
13050 		 * nothing is outstanding, and there is
13051 		 * data to send. Enter persists.
13052 		 */
13053 		rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
13054 	}
13055 }
13056 
13057 static void
13058 rack_log_input_packet(struct tcpcb *tp, struct tcp_rack *rack, struct tcp_ackent *ae, int ackval, uint32_t high_seq)
13059 {
13060 
13061 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
13062 		struct inpcb *inp = tptoinpcb(tp);
13063 		union tcp_log_stackspecific log;
13064 		struct timeval ltv;
13065 		char tcp_hdr_buf[60];
13066 		struct tcphdr *th;
13067 		struct timespec ts;
13068 		uint32_t orig_snd_una;
13069 		uint8_t xx = 0;
13070 
13071 #ifdef NETFLIX_HTTP_LOGGING
13072 		struct http_sendfile_track *http_req;
13073 
13074 		if (SEQ_GT(ae->ack, tp->snd_una)) {
13075 			http_req = tcp_http_find_req_for_seq(tp, (ae->ack-1));
13076 		} else {
13077 			http_req = tcp_http_find_req_for_seq(tp, ae->ack);
13078 		}
13079 #endif
13080 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
13081 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
13082 		if (rack->rack_no_prr == 0)
13083 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
13084 		else
13085 			log.u_bbr.flex1 = 0;
13086 		log.u_bbr.use_lt_bw = rack->r_ent_rec_ns;
13087 		log.u_bbr.use_lt_bw <<= 1;
13088 		log.u_bbr.use_lt_bw |= rack->r_might_revert;
13089 		log.u_bbr.flex2 = rack->r_ctl.rc_num_maps_alloced;
13090 		log.u_bbr.inflight = ctf_flight_size(tp, rack->r_ctl.rc_sacked);
13091 		log.u_bbr.pkts_out = tp->t_maxseg;
13092 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
13093 		log.u_bbr.flex7 = 1;
13094 		log.u_bbr.lost = ae->flags;
13095 		log.u_bbr.cwnd_gain = ackval;
13096 		log.u_bbr.pacing_gain = 0x2;
13097 		if (ae->flags & TSTMP_HDWR) {
13098 			/* Record the hardware timestamp if present */
13099 			log.u_bbr.flex3 = M_TSTMP;
13100 			ts.tv_sec = ae->timestamp / 1000000000;
13101 			ts.tv_nsec = ae->timestamp % 1000000000;
13102 			ltv.tv_sec = ts.tv_sec;
13103 			ltv.tv_usec = ts.tv_nsec / 1000;
13104 			log.u_bbr.lt_epoch = tcp_tv_to_usectick(&ltv);
13105 		} else if (ae->flags & TSTMP_LRO) {
13106 			/* Record the LRO the arrival timestamp */
13107 			log.u_bbr.flex3 = M_TSTMP_LRO;
13108 			ts.tv_sec = ae->timestamp / 1000000000;
13109 			ts.tv_nsec = ae->timestamp % 1000000000;
13110 			ltv.tv_sec = ts.tv_sec;
13111 			ltv.tv_usec = ts.tv_nsec / 1000;
13112 			log.u_bbr.flex5 = tcp_tv_to_usectick(&ltv);
13113 		}
13114 		log.u_bbr.timeStamp = tcp_get_usecs(&ltv);
13115 		/* Log the rcv time */
13116 		log.u_bbr.delRate = ae->timestamp;
13117 #ifdef NETFLIX_HTTP_LOGGING
13118 		log.u_bbr.applimited = tp->t_http_closed;
13119 		log.u_bbr.applimited <<= 8;
13120 		log.u_bbr.applimited |= tp->t_http_open;
13121 		log.u_bbr.applimited <<= 8;
13122 		log.u_bbr.applimited |= tp->t_http_req;
13123 		if (http_req) {
13124 			/* Copy out any client req info */
13125 			/* seconds */
13126 			log.u_bbr.pkt_epoch = (http_req->localtime / HPTS_USEC_IN_SEC);
13127 			/* useconds */
13128 			log.u_bbr.delivered = (http_req->localtime % HPTS_USEC_IN_SEC);
13129 			log.u_bbr.rttProp = http_req->timestamp;
13130 			log.u_bbr.cur_del_rate = http_req->start;
13131 			if (http_req->flags & TCP_HTTP_TRACK_FLG_OPEN) {
13132 				log.u_bbr.flex8 |= 1;
13133 			} else {
13134 				log.u_bbr.flex8 |= 2;
13135 				log.u_bbr.bw_inuse = http_req->end;
13136 			}
13137 			log.u_bbr.flex6 = http_req->start_seq;
13138 			if (http_req->flags & TCP_HTTP_TRACK_FLG_COMP) {
13139 				log.u_bbr.flex8 |= 4;
13140 				log.u_bbr.epoch = http_req->end_seq;
13141 			}
13142 		}
13143 #endif
13144 		memset(tcp_hdr_buf, 0, sizeof(tcp_hdr_buf));
13145 		th = (struct tcphdr *)tcp_hdr_buf;
13146 		th->th_seq = ae->seq;
13147 		th->th_ack = ae->ack;
13148 		th->th_win = ae->win;
13149 		/* Now fill in the ports */
13150 		th->th_sport = inp->inp_fport;
13151 		th->th_dport = inp->inp_lport;
13152 		tcp_set_flags(th, ae->flags);
13153 		/* Now do we have a timestamp option? */
13154 		if (ae->flags & HAS_TSTMP) {
13155 			u_char *cp;
13156 			uint32_t val;
13157 
13158 			th->th_off = ((sizeof(struct tcphdr) + TCPOLEN_TSTAMP_APPA) >> 2);
13159 			cp = (u_char *)(th + 1);
13160 			*cp = TCPOPT_NOP;
13161 			cp++;
13162 			*cp = TCPOPT_NOP;
13163 			cp++;
13164 			*cp = TCPOPT_TIMESTAMP;
13165 			cp++;
13166 			*cp = TCPOLEN_TIMESTAMP;
13167 			cp++;
13168 			val = htonl(ae->ts_value);
13169 			bcopy((char *)&val,
13170 			      (char *)cp, sizeof(uint32_t));
13171 			val = htonl(ae->ts_echo);
13172 			bcopy((char *)&val,
13173 			      (char *)(cp + 4), sizeof(uint32_t));
13174 		} else
13175 			th->th_off = (sizeof(struct tcphdr) >> 2);
13176 
13177 		/*
13178 		 * For sane logging we need to play a little trick.
13179 		 * If the ack were fully processed we would have moved
13180 		 * snd_una to high_seq, but since compressed acks are
13181 		 * processed in two phases, at this point (logging) snd_una
13182 		 * won't be advanced. So we would see multiple acks showing
13183 		 * the advancement. We can prevent that by "pretending" that
13184 		 * snd_una was advanced and then un-advancing it so that the
13185 		 * logging code has the right value for tlb_snd_una.
13186 		 */
13187 		if (tp->snd_una != high_seq) {
13188 			orig_snd_una = tp->snd_una;
13189 			tp->snd_una = high_seq;
13190 			xx = 1;
13191 		} else
13192 			xx = 0;
13193 		TCP_LOG_EVENTP(tp, th,
13194 			       &tptosocket(tp)->so_rcv,
13195 			       &tptosocket(tp)->so_snd, TCP_LOG_IN, 0,
13196 			       0, &log, true, &ltv);
13197 		if (xx) {
13198 			tp->snd_una = orig_snd_una;
13199 		}
13200 	}
13201 
13202 }
13203 
13204 static void
13205 rack_handle_probe_response(struct tcp_rack *rack, uint32_t tiwin, uint32_t us_cts)
13206 {
13207 	uint32_t us_rtt;
13208 	/*
13209 	 * A persist or keep-alive was forced out, update our
13210 	 * min rtt time. Note now worry about lost responses.
13211 	 * When a subsequent keep-alive or persist times out
13212 	 * and forced_ack is still on, then the last probe
13213 	 * was not responded to. In such cases we have a
13214 	 * sysctl that controls the behavior. Either we apply
13215 	 * the rtt but with reduced confidence (0). Or we just
13216 	 * plain don't apply the rtt estimate. Having data flow
13217 	 * will clear the probe_not_answered flag i.e. cum-ack
13218 	 * move forward <or> exiting and reentering persists.
13219 	 */
13220 
13221 	rack->forced_ack = 0;
13222 	rack->rc_tp->t_rxtshift = 0;
13223 	if ((rack->rc_in_persist &&
13224 	     (tiwin == rack->rc_tp->snd_wnd)) ||
13225 	    (rack->rc_in_persist == 0)) {
13226 		/*
13227 		 * In persists only apply the RTT update if this is
13228 		 * a response to our window probe. And that
13229 		 * means the rwnd sent must match the current
13230 		 * snd_wnd. If it does not, then we got a
13231 		 * window update ack instead. For keepalive
13232 		 * we allow the answer no matter what the window.
13233 		 *
13234 		 * Note that if the probe_not_answered is set then
13235 		 * the forced_ack_ts is the oldest one i.e. the first
13236 		 * probe sent that might have been lost. This assures
13237 		 * us that if we do calculate an RTT it is longer not
13238 		 * some short thing.
13239 		 */
13240 		if (rack->rc_in_persist)
13241 			counter_u64_add(rack_persists_acks, 1);
13242 		us_rtt = us_cts - rack->r_ctl.forced_ack_ts;
13243 		if (us_rtt == 0)
13244 			us_rtt = 1;
13245 		if (rack->probe_not_answered == 0) {
13246 			rack_apply_updated_usrtt(rack, us_rtt, us_cts);
13247 			tcp_rack_xmit_timer(rack, us_rtt, 0, us_rtt, 3, NULL, 1);
13248 		} else {
13249 			/* We have a retransmitted probe here too */
13250 			if (rack_apply_rtt_with_reduced_conf) {
13251 				rack_apply_updated_usrtt(rack, us_rtt, us_cts);
13252 				tcp_rack_xmit_timer(rack, us_rtt, 0, us_rtt, 0, NULL, 1);
13253 			}
13254 		}
13255 	}
13256 }
13257 
13258 static int
13259 rack_do_compressed_ack_processing(struct tcpcb *tp, struct socket *so, struct mbuf *m, int nxt_pkt, struct timeval *tv)
13260 {
13261 	/*
13262 	 * Handle a "special" compressed ack mbuf. Each incoming
13263 	 * ack has only four possible dispositions:
13264 	 *
13265 	 * A) It moves the cum-ack forward
13266 	 * B) It is behind the cum-ack.
13267 	 * C) It is a window-update ack.
13268 	 * D) It is a dup-ack.
13269 	 *
13270 	 * Note that we can have between 1 -> TCP_COMP_ACK_ENTRIES
13271 	 * in the incoming mbuf. We also need to still pay attention
13272 	 * to nxt_pkt since there may be another packet after this
13273 	 * one.
13274 	 */
13275 #ifdef TCP_ACCOUNTING
13276 	uint64_t ts_val;
13277 	uint64_t rdstc;
13278 #endif
13279 	int segsiz;
13280 	struct timespec ts;
13281 	struct tcp_rack *rack;
13282 	struct tcp_ackent *ae;
13283 	uint32_t tiwin, ms_cts, cts, acked, acked_amount, high_seq, win_seq, the_win, win_upd_ack;
13284 	int cnt, i, did_out, ourfinisacked = 0;
13285 	struct tcpopt to_holder, *to = NULL;
13286 #ifdef TCP_ACCOUNTING
13287 	int win_up_req = 0;
13288 #endif
13289 	int nsegs = 0;
13290 	int under_pacing = 1;
13291 	int recovery = 0;
13292 #ifdef TCP_ACCOUNTING
13293 	sched_pin();
13294 #endif
13295 	rack = (struct tcp_rack *)tp->t_fb_ptr;
13296 	if (rack->gp_ready &&
13297 	    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT))
13298 		under_pacing = 0;
13299 	else
13300 		under_pacing = 1;
13301 
13302 	if (rack->r_state != tp->t_state)
13303 		rack_set_state(tp, rack);
13304 	if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
13305 	    (tp->t_flags & TF_GPUTINPROG)) {
13306 		/*
13307 		 * We have a goodput in progress
13308 		 * and we have entered a late state.
13309 		 * Do we have enough data in the sb
13310 		 * to handle the GPUT request?
13311 		 */
13312 		uint32_t bytes;
13313 
13314 		bytes = tp->gput_ack - tp->gput_seq;
13315 		if (SEQ_GT(tp->gput_seq, tp->snd_una))
13316 			bytes += tp->gput_seq - tp->snd_una;
13317 		if (bytes > sbavail(&tptosocket(tp)->so_snd)) {
13318 			/*
13319 			 * There are not enough bytes in the socket
13320 			 * buffer that have been sent to cover this
13321 			 * measurement. Cancel it.
13322 			 */
13323 			rack_log_pacing_delay_calc(rack, (tp->gput_ack - tp->gput_seq) /*flex2*/,
13324 						   rack->r_ctl.rc_gp_srtt /*flex1*/,
13325 						   tp->gput_seq,
13326 						   0, 0, 18, __LINE__, NULL, 0);
13327 			tp->t_flags &= ~TF_GPUTINPROG;
13328 		}
13329 	}
13330 	to = &to_holder;
13331 	to->to_flags = 0;
13332 	KASSERT((m->m_len >= sizeof(struct tcp_ackent)),
13333 		("tp:%p m_cmpack:%p with invalid len:%u", tp, m, m->m_len));
13334 	cnt = m->m_len / sizeof(struct tcp_ackent);
13335 	counter_u64_add(rack_multi_single_eq, cnt);
13336 	high_seq = tp->snd_una;
13337 	the_win = tp->snd_wnd;
13338 	win_seq = tp->snd_wl1;
13339 	win_upd_ack = tp->snd_wl2;
13340 	cts = tcp_tv_to_usectick(tv);
13341 	ms_cts = tcp_tv_to_mssectick(tv);
13342 	rack->r_ctl.rc_rcvtime = cts;
13343 	segsiz = ctf_fixed_maxseg(tp);
13344 	if ((rack->rc_gp_dyn_mul) &&
13345 	    (rack->use_fixed_rate == 0) &&
13346 	    (rack->rc_always_pace)) {
13347 		/* Check in on probertt */
13348 		rack_check_probe_rtt(rack, cts);
13349 	}
13350 	for (i = 0; i < cnt; i++) {
13351 #ifdef TCP_ACCOUNTING
13352 		ts_val = get_cyclecount();
13353 #endif
13354 		rack_clear_rate_sample(rack);
13355 		ae = ((mtod(m, struct tcp_ackent *)) + i);
13356 		/* Setup the window */
13357 		tiwin = ae->win << tp->snd_scale;
13358 		if (tiwin > rack->r_ctl.rc_high_rwnd)
13359 			rack->r_ctl.rc_high_rwnd = tiwin;
13360 		/* figure out the type of ack */
13361 		if (SEQ_LT(ae->ack, high_seq)) {
13362 			/* Case B*/
13363 			ae->ack_val_set = ACK_BEHIND;
13364 		} else if (SEQ_GT(ae->ack, high_seq)) {
13365 			/* Case A */
13366 			ae->ack_val_set = ACK_CUMACK;
13367 		} else if ((tiwin == the_win) && (rack->rc_in_persist == 0)){
13368 			/* Case D */
13369 			ae->ack_val_set = ACK_DUPACK;
13370 		} else {
13371 			/* Case C */
13372 			ae->ack_val_set = ACK_RWND;
13373 		}
13374 		rack_log_input_packet(tp, rack, ae, ae->ack_val_set, high_seq);
13375 		/* Validate timestamp */
13376 		if (ae->flags & HAS_TSTMP) {
13377 			/* Setup for a timestamp */
13378 			to->to_flags = TOF_TS;
13379 			ae->ts_echo -= tp->ts_offset;
13380 			to->to_tsecr = ae->ts_echo;
13381 			to->to_tsval = ae->ts_value;
13382 			/*
13383 			 * If echoed timestamp is later than the current time, fall back to
13384 			 * non RFC1323 RTT calculation.  Normalize timestamp if syncookies
13385 			 * were used when this connection was established.
13386 			 */
13387 			if (TSTMP_GT(ae->ts_echo, ms_cts))
13388 				to->to_tsecr = 0;
13389 			if (tp->ts_recent &&
13390 			    TSTMP_LT(ae->ts_value, tp->ts_recent)) {
13391 				if (ctf_ts_check_ac(tp, (ae->flags & 0xff))) {
13392 #ifdef TCP_ACCOUNTING
13393 					rdstc = get_cyclecount();
13394 					if (rdstc > ts_val) {
13395 						counter_u64_add(tcp_proc_time[ae->ack_val_set] ,
13396 								(rdstc - ts_val));
13397 						if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13398 							tp->tcp_proc_time[ae->ack_val_set] += (rdstc - ts_val);
13399 						}
13400 					}
13401 #endif
13402 					continue;
13403 				}
13404 			}
13405 			if (SEQ_LEQ(ae->seq, tp->last_ack_sent) &&
13406 			    SEQ_LEQ(tp->last_ack_sent, ae->seq)) {
13407 				tp->ts_recent_age = tcp_ts_getticks();
13408 				tp->ts_recent = ae->ts_value;
13409 			}
13410 		} else {
13411 			/* Setup for a no options */
13412 			to->to_flags = 0;
13413 		}
13414 		/* Update the rcv time and perform idle reduction possibly */
13415 		if  (tp->t_idle_reduce &&
13416 		     (tp->snd_max == tp->snd_una) &&
13417 		     (TICKS_2_USEC(ticks - tp->t_rcvtime) >= tp->t_rxtcur)) {
13418 			counter_u64_add(rack_input_idle_reduces, 1);
13419 			rack_cc_after_idle(rack, tp);
13420 		}
13421 		tp->t_rcvtime = ticks;
13422 		/* Now what about ECN of a chain of pure ACKs? */
13423 		if (tcp_ecn_input_segment(tp, ae->flags, 0,
13424 			tcp_packets_this_ack(tp, ae->ack),
13425 			ae->codepoint))
13426 			rack_cong_signal(tp, CC_ECN, ae->ack, __LINE__);
13427 #ifdef TCP_ACCOUNTING
13428 		/* Count for the specific type of ack in */
13429 		counter_u64_add(tcp_cnt_counters[ae->ack_val_set], 1);
13430 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13431 			tp->tcp_cnt_counters[ae->ack_val_set]++;
13432 		}
13433 #endif
13434 		/*
13435 		 * Note how we could move up these in the determination
13436 		 * above, but we don't so that way the timestamp checks (and ECN)
13437 		 * is done first before we do any processing on the ACK.
13438 		 * The non-compressed path through the code has this
13439 		 * weakness (noted by @jtl) that it actually does some
13440 		 * processing before verifying the timestamp information.
13441 		 * We don't take that path here which is why we set
13442 		 * the ack_val_set first, do the timestamp and ecn
13443 		 * processing, and then look at what we have setup.
13444 		 */
13445 		if (ae->ack_val_set == ACK_BEHIND) {
13446 			/*
13447 			 * Case B flag reordering, if window is not closed
13448 			 * or it could be a keep-alive or persists
13449 			 */
13450 			if (SEQ_LT(ae->ack, tp->snd_una) && (sbspace(&so->so_rcv) > segsiz)) {
13451 				rack->r_ctl.rc_reorder_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
13452 			}
13453 		} else if (ae->ack_val_set == ACK_DUPACK) {
13454 			/* Case D */
13455 			rack_strike_dupack(rack);
13456 		} else if (ae->ack_val_set == ACK_RWND) {
13457 			/* Case C */
13458 			if ((ae->flags & TSTMP_LRO) || (ae->flags & TSTMP_HDWR)) {
13459 				ts.tv_sec = ae->timestamp / 1000000000;
13460 				ts.tv_nsec = ae->timestamp % 1000000000;
13461 				rack->r_ctl.act_rcv_time.tv_sec = ts.tv_sec;
13462 				rack->r_ctl.act_rcv_time.tv_usec = ts.tv_nsec/1000;
13463 			} else {
13464 				rack->r_ctl.act_rcv_time = *tv;
13465 			}
13466 			if (rack->forced_ack) {
13467 				rack_handle_probe_response(rack, tiwin,
13468 							   tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time));
13469 			}
13470 #ifdef TCP_ACCOUNTING
13471 			win_up_req = 1;
13472 #endif
13473 			win_upd_ack = ae->ack;
13474 			win_seq = ae->seq;
13475 			the_win = tiwin;
13476 			rack_do_win_updates(tp, rack, the_win, win_seq, win_upd_ack, cts, high_seq);
13477 		} else {
13478 			/* Case A */
13479 			if (SEQ_GT(ae->ack, tp->snd_max)) {
13480 				/*
13481 				 * We just send an ack since the incoming
13482 				 * ack is beyond the largest seq we sent.
13483 				 */
13484 				if ((tp->t_flags & TF_ACKNOW) == 0) {
13485 					ctf_ack_war_checks(tp, &rack->r_ctl.challenge_ack_ts, &rack->r_ctl.challenge_ack_cnt);
13486 					if (tp->t_flags && TF_ACKNOW)
13487 						rack->r_wanted_output = 1;
13488 				}
13489 			} else {
13490 				nsegs++;
13491 				/* If the window changed setup to update */
13492 				if (tiwin != tp->snd_wnd) {
13493 					win_upd_ack = ae->ack;
13494 					win_seq = ae->seq;
13495 					the_win = tiwin;
13496 					rack_do_win_updates(tp, rack, the_win, win_seq, win_upd_ack, cts, high_seq);
13497 				}
13498 #ifdef TCP_ACCOUNTING
13499 				/* Account for the acks */
13500 				if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13501 					tp->tcp_cnt_counters[CNT_OF_ACKS_IN] += (((ae->ack - high_seq) + segsiz - 1) / segsiz);
13502 				}
13503 				counter_u64_add(tcp_cnt_counters[CNT_OF_ACKS_IN],
13504 						(((ae->ack - high_seq) + segsiz - 1) / segsiz));
13505 #endif
13506 				high_seq = ae->ack;
13507 				if (rack_verbose_logging && (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
13508 					union tcp_log_stackspecific log;
13509 					struct timeval tv;
13510 
13511 					memset(&log.u_bbr, 0, sizeof(log.u_bbr));
13512 					log.u_bbr.timeStamp = tcp_get_usecs(&tv);
13513 					log.u_bbr.flex1 = high_seq;
13514 					log.u_bbr.flex2 = rack->r_ctl.roundends;
13515 					log.u_bbr.flex3 = rack->r_ctl.current_round;
13516 					log.u_bbr.rttProp = (uint64_t)CC_ALGO(tp)->newround;
13517 					log.u_bbr.flex8 = 8;
13518 					tcp_log_event_(tp, NULL, NULL, NULL, BBR_LOG_CWND, 0,
13519 						       0, &log, false, NULL, NULL, 0, &tv);
13520 				}
13521 				/*
13522 				 * The draft (v3) calls for us to use SEQ_GEQ, but that
13523 				 * causes issues when we are just going app limited. Lets
13524 				 * instead use SEQ_GT <or> where its equal but more data
13525 				 * is outstanding.
13526 				 */
13527 				if ((SEQ_GT(high_seq, rack->r_ctl.roundends)) ||
13528 				    ((high_seq == rack->r_ctl.roundends) &&
13529 				     SEQ_GT(tp->snd_max, tp->snd_una))) {
13530 					rack->r_ctl.current_round++;
13531 					rack->r_ctl.roundends = tp->snd_max;
13532 					if (CC_ALGO(tp)->newround != NULL) {
13533 						CC_ALGO(tp)->newround(&tp->t_ccv, rack->r_ctl.current_round);
13534 					}
13535 				}
13536 				/* Setup our act_rcv_time */
13537 				if ((ae->flags & TSTMP_LRO) || (ae->flags & TSTMP_HDWR)) {
13538 					ts.tv_sec = ae->timestamp / 1000000000;
13539 					ts.tv_nsec = ae->timestamp % 1000000000;
13540 					rack->r_ctl.act_rcv_time.tv_sec = ts.tv_sec;
13541 					rack->r_ctl.act_rcv_time.tv_usec = ts.tv_nsec/1000;
13542 				} else {
13543 					rack->r_ctl.act_rcv_time = *tv;
13544 				}
13545 				rack_process_to_cumack(tp, rack, ae->ack, cts, to);
13546 				if (rack->rc_dsack_round_seen) {
13547 					/* Is the dsack round over? */
13548 					if (SEQ_GEQ(ae->ack, rack->r_ctl.dsack_round_end)) {
13549 						/* Yes it is */
13550 						rack->rc_dsack_round_seen = 0;
13551 						rack_log_dsack_event(rack, 3, __LINE__, 0, 0);
13552 					}
13553 				}
13554 			}
13555 		}
13556 		/* And lets be sure to commit the rtt measurements for this ack */
13557 		tcp_rack_xmit_timer_commit(rack, tp);
13558 #ifdef TCP_ACCOUNTING
13559 		rdstc = get_cyclecount();
13560 		if (rdstc > ts_val) {
13561 			counter_u64_add(tcp_proc_time[ae->ack_val_set] , (rdstc - ts_val));
13562 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13563 				tp->tcp_proc_time[ae->ack_val_set] += (rdstc - ts_val);
13564 				if (ae->ack_val_set == ACK_CUMACK)
13565 					tp->tcp_proc_time[CYC_HANDLE_MAP] += (rdstc - ts_val);
13566 			}
13567 		}
13568 #endif
13569 	}
13570 #ifdef TCP_ACCOUNTING
13571 	ts_val = get_cyclecount();
13572 #endif
13573 	/* Tend to any collapsed window */
13574 	if (SEQ_GT(tp->snd_max, high_seq) && (tp->snd_wnd < (tp->snd_max - high_seq))) {
13575 		/* The peer collapsed the window */
13576 		rack_collapsed_window(rack, (tp->snd_max - high_seq), __LINE__);
13577 	} else if (rack->rc_has_collapsed)
13578 		rack_un_collapse_window(rack, __LINE__);
13579 	if ((rack->r_collapse_point_valid) &&
13580 	    (SEQ_GT(high_seq, rack->r_ctl.high_collapse_point)))
13581 		rack->r_collapse_point_valid = 0;
13582 	acked_amount = acked = (high_seq - tp->snd_una);
13583 	if (acked) {
13584 		/*
13585 		 * Clear the probe not answered flag
13586 		 * since cum-ack moved forward.
13587 		 */
13588 		rack->probe_not_answered = 0;
13589 		if (rack->sack_attack_disable == 0)
13590 			rack_do_decay(rack);
13591 		if (acked >= segsiz) {
13592 			/*
13593 			 * You only get credit for
13594 			 * MSS and greater (and you get extra
13595 			 * credit for larger cum-ack moves).
13596 			 */
13597 			int ac;
13598 
13599 			ac = acked / segsiz;
13600 			rack->r_ctl.ack_count += ac;
13601 			counter_u64_add(rack_ack_total, ac);
13602 		}
13603 		if (rack->r_ctl.ack_count > 0xfff00000) {
13604 			/*
13605 			 * reduce the number to keep us under
13606 			 * a uint32_t.
13607 			 */
13608 			rack->r_ctl.ack_count /= 2;
13609 			rack->r_ctl.sack_count /= 2;
13610 		}
13611 		if (tp->t_flags & TF_NEEDSYN) {
13612 			/*
13613 			 * T/TCP: Connection was half-synchronized, and our SYN has
13614 			 * been ACK'd (so connection is now fully synchronized).  Go
13615 			 * to non-starred state, increment snd_una for ACK of SYN,
13616 			 * and check if we can do window scaling.
13617 			 */
13618 			tp->t_flags &= ~TF_NEEDSYN;
13619 			tp->snd_una++;
13620 			acked_amount = acked = (high_seq - tp->snd_una);
13621 		}
13622 		if (acked > sbavail(&so->so_snd))
13623 			acked_amount = sbavail(&so->so_snd);
13624 #ifdef NETFLIX_EXP_DETECTION
13625 		/*
13626 		 * We only care on a cum-ack move if we are in a sack-disabled
13627 		 * state. We have already added in to the ack_count, and we never
13628 		 * would disable on a cum-ack move, so we only care to do the
13629 		 * detection if it may "undo" it, i.e. we were in disabled already.
13630 		 */
13631 		if (rack->sack_attack_disable)
13632 			rack_do_detection(tp, rack, acked_amount, segsiz);
13633 #endif
13634 		if (IN_FASTRECOVERY(tp->t_flags) &&
13635 		    (rack->rack_no_prr == 0))
13636 			rack_update_prr(tp, rack, acked_amount, high_seq);
13637 		if (IN_RECOVERY(tp->t_flags)) {
13638 			if (SEQ_LT(high_seq, tp->snd_recover) &&
13639 			    (SEQ_LT(high_seq, tp->snd_max))) {
13640 				tcp_rack_partialack(tp);
13641 			} else {
13642 				rack_post_recovery(tp, high_seq);
13643 				recovery = 1;
13644 			}
13645 		}
13646 		/* Handle the rack-log-ack part (sendmap) */
13647 		if ((sbused(&so->so_snd) == 0) &&
13648 		    (acked > acked_amount) &&
13649 		    (tp->t_state >= TCPS_FIN_WAIT_1) &&
13650 		    (tp->t_flags & TF_SENTFIN)) {
13651 			/*
13652 			 * We must be sure our fin
13653 			 * was sent and acked (we can be
13654 			 * in FIN_WAIT_1 without having
13655 			 * sent the fin).
13656 			 */
13657 			ourfinisacked = 1;
13658 			/*
13659 			 * Lets make sure snd_una is updated
13660 			 * since most likely acked_amount = 0 (it
13661 			 * should be).
13662 			 */
13663 			tp->snd_una = high_seq;
13664 		}
13665 		/* Did we make a RTO error? */
13666 		if ((tp->t_flags & TF_PREVVALID) &&
13667 		    ((tp->t_flags & TF_RCVD_TSTMP) == 0)) {
13668 			tp->t_flags &= ~TF_PREVVALID;
13669 			if (tp->t_rxtshift == 1 &&
13670 			    (int)(ticks - tp->t_badrxtwin) < 0)
13671 				rack_cong_signal(tp, CC_RTO_ERR, high_seq, __LINE__);
13672 		}
13673 		/* Handle the data in the socket buffer */
13674 		KMOD_TCPSTAT_ADD(tcps_rcvackpack, 1);
13675 		KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
13676 		if (acked_amount > 0) {
13677 			struct mbuf *mfree;
13678 
13679 			rack_ack_received(tp, rack, high_seq, nsegs, CC_ACK, recovery);
13680 			SOCKBUF_LOCK(&so->so_snd);
13681 			mfree = sbcut_locked(&so->so_snd, acked_amount);
13682 			tp->snd_una = high_seq;
13683 			/* Note we want to hold the sb lock through the sendmap adjust */
13684 			rack_adjust_sendmap(rack, &so->so_snd, tp->snd_una);
13685 			/* Wake up the socket if we have room to write more */
13686 			rack_log_wakeup(tp,rack, &so->so_snd, acked, 2);
13687 			sowwakeup_locked(so);
13688 			m_freem(mfree);
13689 		}
13690 		/* update progress */
13691 		tp->t_acktime = ticks;
13692 		rack_log_progress_event(rack, tp, tp->t_acktime,
13693 					PROGRESS_UPDATE, __LINE__);
13694 		/* Clear out shifts and such */
13695 		tp->t_rxtshift = 0;
13696 		RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
13697 				   rack_rto_min, rack_rto_max, rack->r_ctl.timer_slop);
13698 		rack->rc_tlp_in_progress = 0;
13699 		rack->r_ctl.rc_tlp_cnt_out = 0;
13700 		/* Send recover and snd_nxt must be dragged along */
13701 		if (SEQ_GT(tp->snd_una, tp->snd_recover))
13702 			tp->snd_recover = tp->snd_una;
13703 		if (SEQ_LT(tp->snd_nxt, tp->snd_una))
13704 			tp->snd_nxt = tp->snd_una;
13705 		/*
13706 		 * If the RXT timer is running we want to
13707 		 * stop it, so we can restart a TLP (or new RXT).
13708 		 */
13709 		if (rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT)
13710 			rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
13711 #ifdef NETFLIX_HTTP_LOGGING
13712 		tcp_http_check_for_comp(rack->rc_tp, high_seq);
13713 #endif
13714 		tp->snd_wl2 = high_seq;
13715 		tp->t_dupacks = 0;
13716 		if (under_pacing &&
13717 		    (rack->use_fixed_rate == 0) &&
13718 		    (rack->in_probe_rtt == 0) &&
13719 		    rack->rc_gp_dyn_mul &&
13720 		    rack->rc_always_pace) {
13721 			/* Check if we are dragging bottom */
13722 			rack_check_bottom_drag(tp, rack, so, acked);
13723 		}
13724 		if (tp->snd_una == tp->snd_max) {
13725 			tp->t_flags &= ~TF_PREVVALID;
13726 			rack->r_ctl.retran_during_recovery = 0;
13727 			rack->r_ctl.dsack_byte_cnt = 0;
13728 			rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
13729 			if (rack->r_ctl.rc_went_idle_time == 0)
13730 				rack->r_ctl.rc_went_idle_time = 1;
13731 			rack_log_progress_event(rack, tp, 0, PROGRESS_CLEAR, __LINE__);
13732 			if (sbavail(&tptosocket(tp)->so_snd) == 0)
13733 				tp->t_acktime = 0;
13734 			/* Set so we might enter persists... */
13735 			rack->r_wanted_output = 1;
13736 			rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
13737 			sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
13738 			if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
13739 			    (sbavail(&so->so_snd) == 0) &&
13740 			    (tp->t_flags2 & TF2_DROP_AF_DATA)) {
13741 				/*
13742 				 * The socket was gone and the
13743 				 * peer sent data (not now in the past), time to
13744 				 * reset him.
13745 				 */
13746 				rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
13747 				/* tcp_close will kill the inp pre-log the Reset */
13748 				tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
13749 #ifdef TCP_ACCOUNTING
13750 				rdstc = get_cyclecount();
13751 				if (rdstc > ts_val) {
13752 					counter_u64_add(tcp_proc_time[ACK_CUMACK] , (rdstc - ts_val));
13753 					if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13754 						tp->tcp_proc_time[ACK_CUMACK] += (rdstc - ts_val);
13755 						tp->tcp_proc_time[CYC_HANDLE_ACK] += (rdstc - ts_val);
13756 					}
13757 				}
13758 #endif
13759 				m_freem(m);
13760 				tp = tcp_close(tp);
13761 				if (tp == NULL) {
13762 #ifdef TCP_ACCOUNTING
13763 					sched_unpin();
13764 #endif
13765 					return (1);
13766 				}
13767 				/*
13768 				 * We would normally do drop-with-reset which would
13769 				 * send back a reset. We can't since we don't have
13770 				 * all the needed bits. Instead lets arrange for
13771 				 * a call to tcp_output(). That way since we
13772 				 * are in the closed state we will generate a reset.
13773 				 *
13774 				 * Note if tcp_accounting is on we don't unpin since
13775 				 * we do that after the goto label.
13776 				 */
13777 				goto send_out_a_rst;
13778 			}
13779 			if ((sbused(&so->so_snd) == 0) &&
13780 			    (tp->t_state >= TCPS_FIN_WAIT_1) &&
13781 			    (tp->t_flags & TF_SENTFIN)) {
13782 				/*
13783 				 * If we can't receive any more data, then closing user can
13784 				 * proceed. Starting the timer is contrary to the
13785 				 * specification, but if we don't get a FIN we'll hang
13786 				 * forever.
13787 				 *
13788 				 */
13789 				if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
13790 					soisdisconnected(so);
13791 					tcp_timer_activate(tp, TT_2MSL,
13792 							   (tcp_fast_finwait2_recycle ?
13793 							    tcp_finwait2_timeout :
13794 							    TP_MAXIDLE(tp)));
13795 				}
13796 				if (ourfinisacked == 0) {
13797 					/*
13798 					 * We don't change to fin-wait-2 if we have our fin acked
13799 					 * which means we are probably in TCPS_CLOSING.
13800 					 */
13801 					tcp_state_change(tp, TCPS_FIN_WAIT_2);
13802 				}
13803 			}
13804 		}
13805 		/* Wake up the socket if we have room to write more */
13806 		if (sbavail(&so->so_snd)) {
13807 			rack->r_wanted_output = 1;
13808 			if (ctf_progress_timeout_check(tp, true)) {
13809 				rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
13810 							tp, tick, PROGRESS_DROP, __LINE__);
13811 				/*
13812 				 * We cheat here and don't send a RST, we should send one
13813 				 * when the pacer drops the connection.
13814 				 */
13815 #ifdef TCP_ACCOUNTING
13816 				rdstc = get_cyclecount();
13817 				if (rdstc > ts_val) {
13818 					counter_u64_add(tcp_proc_time[ACK_CUMACK] , (rdstc - ts_val));
13819 					if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13820 						tp->tcp_proc_time[ACK_CUMACK] += (rdstc - ts_val);
13821 						tp->tcp_proc_time[CYC_HANDLE_ACK] += (rdstc - ts_val);
13822 					}
13823 				}
13824 				sched_unpin();
13825 #endif
13826 				(void)tcp_drop(tp, ETIMEDOUT);
13827 				m_freem(m);
13828 				return (1);
13829 			}
13830 		}
13831 		if (ourfinisacked) {
13832 			switch(tp->t_state) {
13833 			case TCPS_CLOSING:
13834 #ifdef TCP_ACCOUNTING
13835 				rdstc = get_cyclecount();
13836 				if (rdstc > ts_val) {
13837 					counter_u64_add(tcp_proc_time[ACK_CUMACK] ,
13838 							(rdstc - ts_val));
13839 					if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13840 						tp->tcp_proc_time[ACK_CUMACK] += (rdstc - ts_val);
13841 						tp->tcp_proc_time[CYC_HANDLE_ACK] += (rdstc - ts_val);
13842 					}
13843 				}
13844 				sched_unpin();
13845 #endif
13846 				tcp_twstart(tp);
13847 				m_freem(m);
13848 				return (1);
13849 				break;
13850 			case TCPS_LAST_ACK:
13851 #ifdef TCP_ACCOUNTING
13852 				rdstc = get_cyclecount();
13853 				if (rdstc > ts_val) {
13854 					counter_u64_add(tcp_proc_time[ACK_CUMACK] ,
13855 							(rdstc - ts_val));
13856 					if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13857 						tp->tcp_proc_time[ACK_CUMACK] += (rdstc - ts_val);
13858 						tp->tcp_proc_time[CYC_HANDLE_ACK] += (rdstc - ts_val);
13859 					}
13860 				}
13861 				sched_unpin();
13862 #endif
13863 				tp = tcp_close(tp);
13864 				ctf_do_drop(m, tp);
13865 				return (1);
13866 				break;
13867 			case TCPS_FIN_WAIT_1:
13868 #ifdef TCP_ACCOUNTING
13869 				rdstc = get_cyclecount();
13870 				if (rdstc > ts_val) {
13871 					counter_u64_add(tcp_proc_time[ACK_CUMACK] ,
13872 							(rdstc - ts_val));
13873 					if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13874 						tp->tcp_proc_time[ACK_CUMACK] += (rdstc - ts_val);
13875 						tp->tcp_proc_time[CYC_HANDLE_ACK] += (rdstc - ts_val);
13876 					}
13877 				}
13878 #endif
13879 				if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
13880 					soisdisconnected(so);
13881 					tcp_timer_activate(tp, TT_2MSL,
13882 							   (tcp_fast_finwait2_recycle ?
13883 							    tcp_finwait2_timeout :
13884 							    TP_MAXIDLE(tp)));
13885 				}
13886 				tcp_state_change(tp, TCPS_FIN_WAIT_2);
13887 				break;
13888 			default:
13889 				break;
13890 			}
13891 		}
13892 		if (rack->r_fast_output) {
13893 			/*
13894 			 * We re doing fast output.. can we expand that?
13895 			 */
13896 			rack_gain_for_fastoutput(rack, tp, so, acked_amount);
13897 		}
13898 #ifdef TCP_ACCOUNTING
13899 		rdstc = get_cyclecount();
13900 		if (rdstc > ts_val) {
13901 			counter_u64_add(tcp_proc_time[ACK_CUMACK] , (rdstc - ts_val));
13902 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13903 				tp->tcp_proc_time[ACK_CUMACK] += (rdstc - ts_val);
13904 				tp->tcp_proc_time[CYC_HANDLE_ACK] += (rdstc - ts_val);
13905 			}
13906 		}
13907 
13908 	} else if (win_up_req) {
13909 		rdstc = get_cyclecount();
13910 		if (rdstc > ts_val) {
13911 			counter_u64_add(tcp_proc_time[ACK_RWND] , (rdstc - ts_val));
13912 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
13913 				tp->tcp_proc_time[ACK_RWND] += (rdstc - ts_val);
13914 			}
13915 		}
13916 #endif
13917 	}
13918 	/* Now is there a next packet, if so we are done */
13919 	m_freem(m);
13920 	did_out = 0;
13921 	if (nxt_pkt) {
13922 #ifdef TCP_ACCOUNTING
13923 		sched_unpin();
13924 #endif
13925 		rack_log_doseg_done(rack, cts, nxt_pkt, did_out, 5, nsegs);
13926 		return (0);
13927 	}
13928 	rack_handle_might_revert(tp, rack);
13929 	ctf_calc_rwin(so, tp);
13930 	if ((rack->r_wanted_output != 0) || (rack->r_fast_output != 0)) {
13931 	send_out_a_rst:
13932 		if (tcp_output(tp) < 0) {
13933 #ifdef TCP_ACCOUNTING
13934 			sched_unpin();
13935 #endif
13936 			return (1);
13937 		}
13938 		did_out = 1;
13939 	}
13940 	rack_free_trim(rack);
13941 #ifdef TCP_ACCOUNTING
13942 	sched_unpin();
13943 #endif
13944 	rack_timer_audit(tp, rack, &so->so_snd);
13945 	rack_log_doseg_done(rack, cts, nxt_pkt, did_out, 6, nsegs);
13946 	return (0);
13947 }
13948 
13949 
13950 static int
13951 rack_do_segment_nounlock(struct mbuf *m, struct tcphdr *th, struct socket *so,
13952     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos,
13953     int32_t nxt_pkt, struct timeval *tv)
13954 {
13955 	struct inpcb *inp = tptoinpcb(tp);
13956 #ifdef TCP_ACCOUNTING
13957 	uint64_t ts_val;
13958 #endif
13959 	int32_t thflags, retval, did_out = 0;
13960 	int32_t way_out = 0;
13961 	/*
13962 	 * cts - is the current time from tv (caller gets ts) in microseconds.
13963 	 * ms_cts - is the current time from tv in milliseconds.
13964 	 * us_cts - is the time that LRO or hardware actually got the packet in microseconds.
13965 	 */
13966 	uint32_t cts, us_cts, ms_cts;
13967 	uint32_t tiwin, high_seq;
13968 	struct timespec ts;
13969 	struct tcpopt to;
13970 	struct tcp_rack *rack;
13971 	struct rack_sendmap *rsm;
13972 	int32_t prev_state = 0;
13973 #ifdef TCP_ACCOUNTING
13974 	int ack_val_set = 0xf;
13975 #endif
13976 	int nsegs;
13977 
13978 	NET_EPOCH_ASSERT();
13979 	INP_WLOCK_ASSERT(inp);
13980 
13981 	/*
13982 	 * tv passed from common code is from either M_TSTMP_LRO or
13983 	 * tcp_get_usecs() if no LRO m_pkthdr timestamp is present.
13984 	 */
13985 	rack = (struct tcp_rack *)tp->t_fb_ptr;
13986 	if (m->m_flags & M_ACKCMP) {
13987 		/*
13988 		 * All compressed ack's are ack's by definition so
13989 		 * remove any ack required flag and then do the processing.
13990 		 */
13991 		rack->rc_ack_required = 0;
13992 		return (rack_do_compressed_ack_processing(tp, so, m, nxt_pkt, tv));
13993 	}
13994 	if (m->m_flags & M_ACKCMP) {
13995 		panic("Impossible reach m has ackcmp? m:%p tp:%p", m, tp);
13996 	}
13997 	cts = tcp_tv_to_usectick(tv);
13998 	ms_cts =  tcp_tv_to_mssectick(tv);
13999 	nsegs = m->m_pkthdr.lro_nsegs;
14000 	counter_u64_add(rack_proc_non_comp_ack, 1);
14001 	thflags = tcp_get_flags(th);
14002 #ifdef TCP_ACCOUNTING
14003 	sched_pin();
14004 	if (thflags & TH_ACK)
14005 		ts_val = get_cyclecount();
14006 #endif
14007 	if ((m->m_flags & M_TSTMP) ||
14008 	    (m->m_flags & M_TSTMP_LRO)) {
14009 		mbuf_tstmp2timespec(m, &ts);
14010 		rack->r_ctl.act_rcv_time.tv_sec = ts.tv_sec;
14011 		rack->r_ctl.act_rcv_time.tv_usec = ts.tv_nsec/1000;
14012 	} else
14013 		rack->r_ctl.act_rcv_time = *tv;
14014 	kern_prefetch(rack, &prev_state);
14015 	prev_state = 0;
14016 	/*
14017 	 * Unscale the window into a 32-bit value. For the SYN_SENT state
14018 	 * the scale is zero.
14019 	 */
14020 	tiwin = th->th_win << tp->snd_scale;
14021 #ifdef TCP_ACCOUNTING
14022 	if (thflags & TH_ACK) {
14023 		/*
14024 		 * We have a tradeoff here. We can either do what we are
14025 		 * doing i.e. pinning to this CPU and then doing the accounting
14026 		 * <or> we could do a critical enter, setup the rdtsc and cpu
14027 		 * as in below, and then validate we are on the same CPU on
14028 		 * exit. I have choosen to not do the critical enter since
14029 		 * that often will gain you a context switch, and instead lock
14030 		 * us (line above this if) to the same CPU with sched_pin(). This
14031 		 * means we may be context switched out for a higher priority
14032 		 * interupt but we won't be moved to another CPU.
14033 		 *
14034 		 * If this occurs (which it won't very often since we most likely
14035 		 * are running this code in interupt context and only a higher
14036 		 * priority will bump us ... clock?) we will falsely add in
14037 		 * to the time the interupt processing time plus the ack processing
14038 		 * time. This is ok since its a rare event.
14039 		 */
14040 		ack_val_set = tcp_do_ack_accounting(tp, th, &to, tiwin,
14041 						    ctf_fixed_maxseg(tp));
14042 	}
14043 #endif
14044 	/*
14045 	 * Parse options on any incoming segment.
14046 	 */
14047 	memset(&to, 0, sizeof(to));
14048 	tcp_dooptions(&to, (u_char *)(th + 1),
14049 	    (th->th_off << 2) - sizeof(struct tcphdr),
14050 	    (thflags & TH_SYN) ? TO_SYN : 0);
14051 	KASSERT(tp->t_state > TCPS_LISTEN, ("%s: TCPS_LISTEN",
14052 	    __func__));
14053 	KASSERT(tp->t_state != TCPS_TIME_WAIT, ("%s: TCPS_TIME_WAIT",
14054 	    __func__));
14055 
14056 	if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
14057 	    (tp->t_flags & TF_GPUTINPROG)) {
14058 		/*
14059 		 * We have a goodput in progress
14060 		 * and we have entered a late state.
14061 		 * Do we have enough data in the sb
14062 		 * to handle the GPUT request?
14063 		 */
14064 		uint32_t bytes;
14065 
14066 		bytes = tp->gput_ack - tp->gput_seq;
14067 		if (SEQ_GT(tp->gput_seq, tp->snd_una))
14068 			bytes += tp->gput_seq - tp->snd_una;
14069 		if (bytes > sbavail(&tptosocket(tp)->so_snd)) {
14070 			/*
14071 			 * There are not enough bytes in the socket
14072 			 * buffer that have been sent to cover this
14073 			 * measurement. Cancel it.
14074 			 */
14075 			rack_log_pacing_delay_calc(rack, (tp->gput_ack - tp->gput_seq) /*flex2*/,
14076 						   rack->r_ctl.rc_gp_srtt /*flex1*/,
14077 						   tp->gput_seq,
14078 						   0, 0, 18, __LINE__, NULL, 0);
14079 			tp->t_flags &= ~TF_GPUTINPROG;
14080 		}
14081 	}
14082 	high_seq = th->th_ack;
14083 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
14084 		union tcp_log_stackspecific log;
14085 		struct timeval ltv;
14086 #ifdef NETFLIX_HTTP_LOGGING
14087 		struct http_sendfile_track *http_req;
14088 
14089 		if (SEQ_GT(th->th_ack, tp->snd_una)) {
14090 			http_req = tcp_http_find_req_for_seq(tp, (th->th_ack-1));
14091 		} else {
14092 			http_req = tcp_http_find_req_for_seq(tp, th->th_ack);
14093 		}
14094 #endif
14095 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
14096 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
14097 		if (rack->rack_no_prr == 0)
14098 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
14099 		else
14100 			log.u_bbr.flex1 = 0;
14101 		log.u_bbr.use_lt_bw = rack->r_ent_rec_ns;
14102 		log.u_bbr.use_lt_bw <<= 1;
14103 		log.u_bbr.use_lt_bw |= rack->r_might_revert;
14104 		log.u_bbr.flex2 = rack->r_ctl.rc_num_maps_alloced;
14105 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
14106 		log.u_bbr.pkts_out = rack->rc_tp->t_maxseg;
14107 		log.u_bbr.flex3 = m->m_flags;
14108 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
14109 		log.u_bbr.lost = thflags;
14110 		log.u_bbr.pacing_gain = 0x1;
14111 #ifdef TCP_ACCOUNTING
14112 		log.u_bbr.cwnd_gain = ack_val_set;
14113 #endif
14114 		log.u_bbr.flex7 = 2;
14115 		if (m->m_flags & M_TSTMP) {
14116 			/* Record the hardware timestamp if present */
14117 			mbuf_tstmp2timespec(m, &ts);
14118 			ltv.tv_sec = ts.tv_sec;
14119 			ltv.tv_usec = ts.tv_nsec / 1000;
14120 			log.u_bbr.lt_epoch = tcp_tv_to_usectick(&ltv);
14121 		} else if (m->m_flags & M_TSTMP_LRO) {
14122 			/* Record the LRO the arrival timestamp */
14123 			mbuf_tstmp2timespec(m, &ts);
14124 			ltv.tv_sec = ts.tv_sec;
14125 			ltv.tv_usec = ts.tv_nsec / 1000;
14126 			log.u_bbr.flex5 = tcp_tv_to_usectick(&ltv);
14127 		}
14128 		log.u_bbr.timeStamp = tcp_get_usecs(&ltv);
14129 		/* Log the rcv time */
14130 		log.u_bbr.delRate = m->m_pkthdr.rcv_tstmp;
14131 #ifdef NETFLIX_HTTP_LOGGING
14132 		log.u_bbr.applimited = tp->t_http_closed;
14133 		log.u_bbr.applimited <<= 8;
14134 		log.u_bbr.applimited |= tp->t_http_open;
14135 		log.u_bbr.applimited <<= 8;
14136 		log.u_bbr.applimited |= tp->t_http_req;
14137 		if (http_req) {
14138 			/* Copy out any client req info */
14139 			/* seconds */
14140 			log.u_bbr.pkt_epoch = (http_req->localtime / HPTS_USEC_IN_SEC);
14141 			/* useconds */
14142 			log.u_bbr.delivered = (http_req->localtime % HPTS_USEC_IN_SEC);
14143 			log.u_bbr.rttProp = http_req->timestamp;
14144 			log.u_bbr.cur_del_rate = http_req->start;
14145 			if (http_req->flags & TCP_HTTP_TRACK_FLG_OPEN) {
14146 				log.u_bbr.flex8 |= 1;
14147 			} else {
14148 				log.u_bbr.flex8 |= 2;
14149 				log.u_bbr.bw_inuse = http_req->end;
14150 			}
14151 			log.u_bbr.flex6 = http_req->start_seq;
14152 			if (http_req->flags & TCP_HTTP_TRACK_FLG_COMP) {
14153 				log.u_bbr.flex8 |= 4;
14154 				log.u_bbr.epoch = http_req->end_seq;
14155 			}
14156 		}
14157 #endif
14158 		TCP_LOG_EVENTP(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_IN, 0,
14159 		    tlen, &log, true, &ltv);
14160 	}
14161 	/* Remove ack required flag if set, we have one  */
14162 	if (thflags & TH_ACK)
14163 		rack->rc_ack_required = 0;
14164 	if ((thflags & TH_SYN) && (thflags & TH_FIN) && V_drop_synfin) {
14165 		way_out = 4;
14166 		retval = 0;
14167 		m_freem(m);
14168 		goto done_with_input;
14169 	}
14170 	/*
14171 	 * If a segment with the ACK-bit set arrives in the SYN-SENT state
14172 	 * check SEQ.ACK first as described on page 66 of RFC 793, section 3.9.
14173 	 */
14174 	if ((tp->t_state == TCPS_SYN_SENT) && (thflags & TH_ACK) &&
14175 	    (SEQ_LEQ(th->th_ack, tp->iss) || SEQ_GT(th->th_ack, tp->snd_max))) {
14176 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
14177 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
14178 #ifdef TCP_ACCOUNTING
14179 		sched_unpin();
14180 #endif
14181 		return (1);
14182 	}
14183 	/*
14184 	 * If timestamps were negotiated during SYN/ACK and a
14185 	 * segment without a timestamp is received, silently drop
14186 	 * the segment, unless it is a RST segment or missing timestamps are
14187 	 * tolerated.
14188 	 * See section 3.2 of RFC 7323.
14189 	 */
14190 	if ((tp->t_flags & TF_RCVD_TSTMP) && !(to.to_flags & TOF_TS) &&
14191 	    ((thflags & TH_RST) == 0) && (V_tcp_tolerate_missing_ts == 0)) {
14192 		way_out = 5;
14193 		retval = 0;
14194 		m_freem(m);
14195 		goto done_with_input;
14196 	}
14197 
14198 	/*
14199 	 * Segment received on connection. Reset idle time and keep-alive
14200 	 * timer. XXX: This should be done after segment validation to
14201 	 * ignore broken/spoofed segs.
14202 	 */
14203 	if  (tp->t_idle_reduce &&
14204 	     (tp->snd_max == tp->snd_una) &&
14205 	     (TICKS_2_USEC(ticks - tp->t_rcvtime) >= tp->t_rxtcur)) {
14206 		counter_u64_add(rack_input_idle_reduces, 1);
14207 		rack_cc_after_idle(rack, tp);
14208 	}
14209 	tp->t_rcvtime = ticks;
14210 #ifdef STATS
14211 	stats_voi_update_abs_ulong(tp->t_stats, VOI_TCP_FRWIN, tiwin);
14212 #endif
14213 	if (tiwin > rack->r_ctl.rc_high_rwnd)
14214 		rack->r_ctl.rc_high_rwnd = tiwin;
14215 	/*
14216 	 * TCP ECN processing. XXXJTL: If we ever use ECN, we need to move
14217 	 * this to occur after we've validated the segment.
14218 	 */
14219 	if (tcp_ecn_input_segment(tp, thflags, tlen,
14220 	    tcp_packets_this_ack(tp, th->th_ack),
14221 	    iptos))
14222 		rack_cong_signal(tp, CC_ECN, th->th_ack, __LINE__);
14223 
14224 	/*
14225 	 * If echoed timestamp is later than the current time, fall back to
14226 	 * non RFC1323 RTT calculation.  Normalize timestamp if syncookies
14227 	 * were used when this connection was established.
14228 	 */
14229 	if ((to.to_flags & TOF_TS) && (to.to_tsecr != 0)) {
14230 		to.to_tsecr -= tp->ts_offset;
14231 		if (TSTMP_GT(to.to_tsecr, ms_cts))
14232 			to.to_tsecr = 0;
14233 	}
14234 
14235 	/*
14236 	 * If its the first time in we need to take care of options and
14237 	 * verify we can do SACK for rack!
14238 	 */
14239 	if (rack->r_state == 0) {
14240 		/* Should be init'd by rack_init() */
14241 		KASSERT(rack->rc_inp != NULL,
14242 		    ("%s: rack->rc_inp unexpectedly NULL", __func__));
14243 		if (rack->rc_inp == NULL) {
14244 			rack->rc_inp = inp;
14245 		}
14246 
14247 		/*
14248 		 * Process options only when we get SYN/ACK back. The SYN
14249 		 * case for incoming connections is handled in tcp_syncache.
14250 		 * According to RFC1323 the window field in a SYN (i.e., a
14251 		 * <SYN> or <SYN,ACK>) segment itself is never scaled. XXX
14252 		 * this is traditional behavior, may need to be cleaned up.
14253 		 */
14254 		if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) {
14255 			/* Handle parallel SYN for ECN */
14256 			tcp_ecn_input_parallel_syn(tp, thflags, iptos);
14257 			if ((to.to_flags & TOF_SCALE) &&
14258 			    (tp->t_flags & TF_REQ_SCALE)) {
14259 				tp->t_flags |= TF_RCVD_SCALE;
14260 				tp->snd_scale = to.to_wscale;
14261 			} else
14262 				tp->t_flags &= ~TF_REQ_SCALE;
14263 			/*
14264 			 * Initial send window.  It will be updated with the
14265 			 * next incoming segment to the scaled value.
14266 			 */
14267 			tp->snd_wnd = th->th_win;
14268 			rack_validate_fo_sendwin_up(tp, rack);
14269 			if ((to.to_flags & TOF_TS) &&
14270 			    (tp->t_flags & TF_REQ_TSTMP)) {
14271 				tp->t_flags |= TF_RCVD_TSTMP;
14272 				tp->ts_recent = to.to_tsval;
14273 				tp->ts_recent_age = cts;
14274 			} else
14275 				tp->t_flags &= ~TF_REQ_TSTMP;
14276 			if (to.to_flags & TOF_MSS) {
14277 				tcp_mss(tp, to.to_mss);
14278 			}
14279 			if ((tp->t_flags & TF_SACK_PERMIT) &&
14280 			    (to.to_flags & TOF_SACKPERM) == 0)
14281 				tp->t_flags &= ~TF_SACK_PERMIT;
14282 			if (IS_FASTOPEN(tp->t_flags)) {
14283 				if (to.to_flags & TOF_FASTOPEN) {
14284 					uint16_t mss;
14285 
14286 					if (to.to_flags & TOF_MSS)
14287 						mss = to.to_mss;
14288 					else
14289 						if ((inp->inp_vflag & INP_IPV6) != 0)
14290 							mss = TCP6_MSS;
14291 						else
14292 							mss = TCP_MSS;
14293 					tcp_fastopen_update_cache(tp, mss,
14294 					    to.to_tfo_len, to.to_tfo_cookie);
14295 				} else
14296 					tcp_fastopen_disable_path(tp);
14297 			}
14298 		}
14299 		/*
14300 		 * At this point we are at the initial call. Here we decide
14301 		 * if we are doing RACK or not. We do this by seeing if
14302 		 * TF_SACK_PERMIT is set and the sack-not-required is clear.
14303 		 * The code now does do dup-ack counting so if you don't
14304 		 * switch back you won't get rack & TLP, but you will still
14305 		 * get this stack.
14306 		 */
14307 
14308 		if ((rack_sack_not_required == 0) &&
14309 		    ((tp->t_flags & TF_SACK_PERMIT) == 0)) {
14310 			tcp_switch_back_to_default(tp);
14311 			(*tp->t_fb->tfb_tcp_do_segment) (m, th, so, tp, drop_hdrlen,
14312 			    tlen, iptos);
14313 #ifdef TCP_ACCOUNTING
14314 			sched_unpin();
14315 #endif
14316 			return (1);
14317 		}
14318 		tcp_set_hpts(inp);
14319 		sack_filter_clear(&rack->r_ctl.rack_sf, th->th_ack);
14320 	}
14321 	if (thflags & TH_FIN)
14322 		tcp_log_end_status(tp, TCP_EI_STATUS_CLIENT_FIN);
14323 	us_cts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
14324 	if ((rack->rc_gp_dyn_mul) &&
14325 	    (rack->use_fixed_rate == 0) &&
14326 	    (rack->rc_always_pace)) {
14327 		/* Check in on probertt */
14328 		rack_check_probe_rtt(rack, us_cts);
14329 	}
14330 	rack_clear_rate_sample(rack);
14331 	if ((rack->forced_ack) &&
14332 	    ((tcp_get_flags(th) & TH_RST) == 0)) {
14333 		rack_handle_probe_response(rack, tiwin, us_cts);
14334 	}
14335 	/*
14336 	 * This is the one exception case where we set the rack state
14337 	 * always. All other times (timers etc) we must have a rack-state
14338 	 * set (so we assure we have done the checks above for SACK).
14339 	 */
14340 	rack->r_ctl.rc_rcvtime = cts;
14341 	if (rack->r_state != tp->t_state)
14342 		rack_set_state(tp, rack);
14343 	if (SEQ_GT(th->th_ack, tp->snd_una) &&
14344 	    (rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree)) != NULL)
14345 		kern_prefetch(rsm, &prev_state);
14346 	prev_state = rack->r_state;
14347 	retval = (*rack->r_substate) (m, th, so,
14348 	    tp, &to, drop_hdrlen,
14349 	    tlen, tiwin, thflags, nxt_pkt, iptos);
14350 	if (retval == 0) {
14351 		/*
14352 		 * If retval is 1 the tcb is unlocked and most likely the tp
14353 		 * is gone.
14354 		 */
14355 		INP_WLOCK_ASSERT(inp);
14356 		if ((rack->rc_gp_dyn_mul) &&
14357 		    (rack->rc_always_pace) &&
14358 		    (rack->use_fixed_rate == 0) &&
14359 		    rack->in_probe_rtt &&
14360 		    (rack->r_ctl.rc_time_probertt_starts == 0)) {
14361 			/*
14362 			 * If we are going for target, lets recheck before
14363 			 * we output.
14364 			 */
14365 			rack_check_probe_rtt(rack, us_cts);
14366 		}
14367 		if (rack->set_pacing_done_a_iw == 0) {
14368 			/* How much has been acked? */
14369 			if ((tp->snd_una - tp->iss) > (ctf_fixed_maxseg(tp) * 10)) {
14370 				/* We have enough to set in the pacing segment size */
14371 				rack->set_pacing_done_a_iw = 1;
14372 				rack_set_pace_segments(tp, rack, __LINE__, NULL);
14373 			}
14374 		}
14375 		tcp_rack_xmit_timer_commit(rack, tp);
14376 #ifdef TCP_ACCOUNTING
14377 		/*
14378 		 * If we set the ack_val_se to what ack processing we are doing
14379 		 * we also want to track how many cycles we burned. Note
14380 		 * the bits after tcp_output we let be "free". This is because
14381 		 * we are also tracking the tcp_output times as well. Note the
14382 		 * use of 0xf here since we only have 11 counter (0 - 0xa) and
14383 		 * 0xf cannot be returned and is what we initialize it too to
14384 		 * indicate we are not doing the tabulations.
14385 		 */
14386 		if (ack_val_set != 0xf) {
14387 			uint64_t crtsc;
14388 
14389 			crtsc = get_cyclecount();
14390 			counter_u64_add(tcp_proc_time[ack_val_set] , (crtsc - ts_val));
14391 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
14392 				tp->tcp_proc_time[ack_val_set] += (crtsc - ts_val);
14393 			}
14394 		}
14395 #endif
14396 		if (nxt_pkt == 0) {
14397 			if ((rack->r_wanted_output != 0) || (rack->r_fast_output != 0)) {
14398 do_output_now:
14399 				if (tcp_output(tp) < 0)
14400 					return (1);
14401 				did_out = 1;
14402 			}
14403 			rack_start_hpts_timer(rack, tp, cts, 0, 0, 0);
14404 			rack_free_trim(rack);
14405 		}
14406 		/* Update any rounds needed */
14407 		if (rack_verbose_logging &&  (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
14408 			union tcp_log_stackspecific log;
14409 			struct timeval tv;
14410 
14411 			memset(&log.u_bbr, 0, sizeof(log.u_bbr));
14412 			log.u_bbr.timeStamp = tcp_get_usecs(&tv);
14413 			log.u_bbr.flex1 = high_seq;
14414 			log.u_bbr.flex2 = rack->r_ctl.roundends;
14415 			log.u_bbr.flex3 = rack->r_ctl.current_round;
14416 			log.u_bbr.rttProp = (uint64_t)CC_ALGO(tp)->newround;
14417 			log.u_bbr.flex8 = 9;
14418 			tcp_log_event_(tp, NULL, NULL, NULL, BBR_LOG_CWND, 0,
14419 				       0, &log, false, NULL, NULL, 0, &tv);
14420 		}
14421 		/*
14422 		 * The draft (v3) calls for us to use SEQ_GEQ, but that
14423 		 * causes issues when we are just going app limited. Lets
14424 		 * instead use SEQ_GT <or> where its equal but more data
14425 		 * is outstanding.
14426 		 */
14427 		if ((SEQ_GT(tp->snd_una, rack->r_ctl.roundends)) ||
14428 		    ((tp->snd_una == rack->r_ctl.roundends) && SEQ_GT(tp->snd_max, tp->snd_una))) {
14429 			rack->r_ctl.current_round++;
14430 			rack->r_ctl.roundends = tp->snd_max;
14431 			if (CC_ALGO(tp)->newround != NULL) {
14432 				CC_ALGO(tp)->newround(&tp->t_ccv, rack->r_ctl.current_round);
14433 			}
14434 		}
14435 		if ((nxt_pkt == 0) &&
14436 		    ((rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) == 0) &&
14437 		    (SEQ_GT(tp->snd_max, tp->snd_una) ||
14438 		     (tp->t_flags & TF_DELACK) ||
14439 		     ((V_tcp_always_keepalive || rack->rc_inp->inp_socket->so_options & SO_KEEPALIVE) &&
14440 		      (tp->t_state <= TCPS_CLOSING)))) {
14441 			/* We could not send (probably in the hpts but stopped the timer earlier)? */
14442 			if ((tp->snd_max == tp->snd_una) &&
14443 			    ((tp->t_flags & TF_DELACK) == 0) &&
14444 			    (tcp_in_hpts(rack->rc_inp)) &&
14445 			    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
14446 				/* keep alive not needed if we are hptsi output yet */
14447 				;
14448 			} else {
14449 				int late = 0;
14450 				if (tcp_in_hpts(inp)) {
14451 					if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
14452 						us_cts = tcp_get_usecs(NULL);
14453 						if (TSTMP_GT(rack->r_ctl.rc_last_output_to, us_cts)) {
14454 							rack->r_early = 1;
14455 							rack->r_ctl.rc_agg_early += (rack->r_ctl.rc_last_output_to - us_cts);
14456 						} else
14457 							late = 1;
14458 						rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
14459 					}
14460 					tcp_hpts_remove(inp);
14461 				}
14462 				if (late && (did_out == 0)) {
14463 					/*
14464 					 * We are late in the sending
14465 					 * and we did not call the output
14466 					 * (this probably should not happen).
14467 					 */
14468 					goto do_output_now;
14469 				}
14470 				rack_start_hpts_timer(rack, tp, tcp_get_usecs(NULL), 0, 0, 0);
14471 			}
14472 			way_out = 1;
14473 		} else if (nxt_pkt == 0) {
14474 			/* Do we have the correct timer running? */
14475 			rack_timer_audit(tp, rack, &so->so_snd);
14476 			way_out = 2;
14477 		}
14478 	done_with_input:
14479 		rack_log_doseg_done(rack, cts, nxt_pkt, did_out, way_out, max(1, nsegs));
14480 		if (did_out)
14481 			rack->r_wanted_output = 0;
14482 #ifdef TCP_ACCOUNTING
14483 	} else {
14484 		/*
14485 		 * Track the time (see above).
14486 		 */
14487 		if (ack_val_set != 0xf) {
14488 			uint64_t crtsc;
14489 
14490 			crtsc = get_cyclecount();
14491 			counter_u64_add(tcp_proc_time[ack_val_set] , (crtsc - ts_val));
14492 			/*
14493 			 * Note we *DO NOT* increment the per-tcb counters since
14494 			 * in the else the TP may be gone!!
14495 			 */
14496 		}
14497 #endif
14498 	}
14499 #ifdef TCP_ACCOUNTING
14500 	sched_unpin();
14501 #endif
14502 	return (retval);
14503 }
14504 
14505 void
14506 rack_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
14507     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos)
14508 {
14509 	struct timeval tv;
14510 
14511 	/* First lets see if we have old packets */
14512 	if (tp->t_in_pkt) {
14513 		if (ctf_do_queued_segments(so, tp, 1)) {
14514 			m_freem(m);
14515 			return;
14516 		}
14517 	}
14518 	if (m->m_flags & M_TSTMP_LRO) {
14519 		mbuf_tstmp2timeval(m, &tv);
14520 	} else {
14521 		/* Should not be should we kassert instead? */
14522 		tcp_get_usecs(&tv);
14523 	}
14524 	if (rack_do_segment_nounlock(m, th, so, tp,
14525 				     drop_hdrlen, tlen, iptos, 0, &tv) == 0) {
14526 		INP_WUNLOCK(tptoinpcb(tp));
14527 	}
14528 }
14529 
14530 struct rack_sendmap *
14531 tcp_rack_output(struct tcpcb *tp, struct tcp_rack *rack, uint32_t tsused)
14532 {
14533 	struct rack_sendmap *rsm = NULL;
14534 	int32_t idx;
14535 	uint32_t srtt = 0, thresh = 0, ts_low = 0;
14536 
14537 	/* Return the next guy to be re-transmitted */
14538 	if (RB_EMPTY(&rack->r_ctl.rc_mtree)) {
14539 		return (NULL);
14540 	}
14541 	if (tp->t_flags & TF_SENTFIN) {
14542 		/* retran the end FIN? */
14543 		return (NULL);
14544 	}
14545 	/* ok lets look at this one */
14546 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
14547 	if (rack->r_must_retran && rsm && (rsm->r_flags & RACK_MUST_RXT)) {
14548 		return (rsm);
14549 	}
14550 	if (rsm && ((rsm->r_flags & RACK_ACKED) == 0)) {
14551 		goto check_it;
14552 	}
14553 	rsm = rack_find_lowest_rsm(rack);
14554 	if (rsm == NULL) {
14555 		return (NULL);
14556 	}
14557 check_it:
14558 	if (((rack->rc_tp->t_flags & TF_SACK_PERMIT) == 0) &&
14559 	    (rsm->r_dupack >= DUP_ACK_THRESHOLD)) {
14560 		/*
14561 		 * No sack so we automatically do the 3 strikes and
14562 		 * retransmit (no rack timer would be started).
14563 		 */
14564 
14565 		return (rsm);
14566 	}
14567 	if (rsm->r_flags & RACK_ACKED) {
14568 		return (NULL);
14569 	}
14570 	if (((rsm->r_flags & RACK_SACK_PASSED) == 0) &&
14571 	    (rsm->r_dupack < DUP_ACK_THRESHOLD)) {
14572 		/* Its not yet ready */
14573 		return (NULL);
14574 	}
14575 	srtt = rack_grab_rtt(tp, rack);
14576 	idx = rsm->r_rtr_cnt - 1;
14577 	ts_low = (uint32_t)rsm->r_tim_lastsent[idx];
14578 	thresh = rack_calc_thresh_rack(rack, srtt, tsused);
14579 	if ((tsused == ts_low) ||
14580 	    (TSTMP_LT(tsused, ts_low))) {
14581 		/* No time since sending */
14582 		return (NULL);
14583 	}
14584 	if ((tsused - ts_low) < thresh) {
14585 		/* It has not been long enough yet */
14586 		return (NULL);
14587 	}
14588 	if ((rsm->r_dupack >= DUP_ACK_THRESHOLD) ||
14589 	    ((rsm->r_flags & RACK_SACK_PASSED) &&
14590 	     (rack->sack_attack_disable == 0))) {
14591 		/*
14592 		 * We have passed the dup-ack threshold <or>
14593 		 * a SACK has indicated this is missing.
14594 		 * Note that if you are a declared attacker
14595 		 * it is only the dup-ack threshold that
14596 		 * will cause retransmits.
14597 		 */
14598 		/* log retransmit reason */
14599 		rack_log_retran_reason(rack, rsm, (tsused - ts_low), thresh, 1);
14600 		rack->r_fast_output = 0;
14601 		return (rsm);
14602 	}
14603 	return (NULL);
14604 }
14605 
14606 static void
14607 rack_log_pacing_delay_calc(struct tcp_rack *rack, uint32_t len, uint32_t slot,
14608 			   uint64_t bw_est, uint64_t bw, uint64_t len_time, int method,
14609 			   int line, struct rack_sendmap *rsm, uint8_t quality)
14610 {
14611 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
14612 		union tcp_log_stackspecific log;
14613 		struct timeval tv;
14614 
14615 		memset(&log, 0, sizeof(log));
14616 		log.u_bbr.flex1 = slot;
14617 		log.u_bbr.flex2 = len;
14618 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_min_segs;
14619 		log.u_bbr.flex4 = rack->r_ctl.rc_pace_max_segs;
14620 		log.u_bbr.flex5 = rack->r_ctl.rack_per_of_gp_ss;
14621 		log.u_bbr.flex6 = rack->r_ctl.rack_per_of_gp_ca;
14622 		log.u_bbr.use_lt_bw = rack->rc_ack_can_sendout_data;
14623 		log.u_bbr.use_lt_bw <<= 1;
14624 		log.u_bbr.use_lt_bw |= rack->r_late;
14625 		log.u_bbr.use_lt_bw <<= 1;
14626 		log.u_bbr.use_lt_bw |= rack->r_early;
14627 		log.u_bbr.use_lt_bw <<= 1;
14628 		log.u_bbr.use_lt_bw |= rack->app_limited_needs_set;
14629 		log.u_bbr.use_lt_bw <<= 1;
14630 		log.u_bbr.use_lt_bw |= rack->rc_gp_filled;
14631 		log.u_bbr.use_lt_bw <<= 1;
14632 		log.u_bbr.use_lt_bw |= rack->measure_saw_probe_rtt;
14633 		log.u_bbr.use_lt_bw <<= 1;
14634 		log.u_bbr.use_lt_bw |= rack->in_probe_rtt;
14635 		log.u_bbr.use_lt_bw <<= 1;
14636 		log.u_bbr.use_lt_bw |= rack->gp_ready;
14637 		log.u_bbr.pkt_epoch = line;
14638 		log.u_bbr.epoch = rack->r_ctl.rc_agg_delayed;
14639 		log.u_bbr.lt_epoch = rack->r_ctl.rc_agg_early;
14640 		log.u_bbr.applimited = rack->r_ctl.rack_per_of_gp_rec;
14641 		log.u_bbr.bw_inuse = bw_est;
14642 		log.u_bbr.delRate = bw;
14643 		if (rack->r_ctl.gp_bw == 0)
14644 			log.u_bbr.cur_del_rate = 0;
14645 		else
14646 			log.u_bbr.cur_del_rate = rack_get_bw(rack);
14647 		log.u_bbr.rttProp = len_time;
14648 		log.u_bbr.pkts_out = rack->r_ctl.rc_rack_min_rtt;
14649 		log.u_bbr.lost = rack->r_ctl.rc_probertt_sndmax_atexit;
14650 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, rsm);
14651 		if (rack->r_ctl.cwnd_to_use < rack->rc_tp->snd_ssthresh) {
14652 			/* We are in slow start */
14653 			log.u_bbr.flex7 = 1;
14654 		} else {
14655 			/* we are on congestion avoidance */
14656 			log.u_bbr.flex7 = 0;
14657 		}
14658 		log.u_bbr.flex8 = method;
14659 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
14660 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
14661 		log.u_bbr.cwnd_gain = rack->rc_gp_saw_rec;
14662 		log.u_bbr.cwnd_gain <<= 1;
14663 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ss;
14664 		log.u_bbr.cwnd_gain <<= 1;
14665 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ca;
14666 		log.u_bbr.bbr_substate = quality;
14667 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
14668 		    &rack->rc_inp->inp_socket->so_rcv,
14669 		    &rack->rc_inp->inp_socket->so_snd,
14670 		    BBR_LOG_HPTSI_CALC, 0,
14671 		    0, &log, false, &tv);
14672 	}
14673 }
14674 
14675 static uint32_t
14676 rack_get_pacing_len(struct tcp_rack *rack, uint64_t bw, uint32_t mss)
14677 {
14678 	uint32_t new_tso, user_max;
14679 
14680 	user_max = rack->rc_user_set_max_segs * mss;
14681 	if (rack->rc_force_max_seg) {
14682 		return (user_max);
14683 	}
14684 	if (rack->use_fixed_rate &&
14685 	    ((rack->r_ctl.crte == NULL) ||
14686 	     (bw != rack->r_ctl.crte->rate))) {
14687 		/* Use the user mss since we are not exactly matched */
14688 		return (user_max);
14689 	}
14690 	new_tso = tcp_get_pacing_burst_size(rack->rc_tp, bw, mss, rack_pace_one_seg, rack->r_ctl.crte, NULL);
14691 	if (new_tso > user_max)
14692 		new_tso = user_max;
14693 	return (new_tso);
14694 }
14695 
14696 static int32_t
14697 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)
14698 {
14699 	uint64_t lentim, fill_bw;
14700 
14701 	/* Lets first see if we are full, if so continue with normal rate */
14702 	rack->r_via_fill_cw = 0;
14703 	if (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) > rack->r_ctl.cwnd_to_use)
14704 		return (slot);
14705 	if ((ctf_outstanding(rack->rc_tp) + (segsiz-1)) > rack->rc_tp->snd_wnd)
14706 		return (slot);
14707 	if (rack->r_ctl.rc_last_us_rtt == 0)
14708 		return (slot);
14709 	if (rack->rc_pace_fill_if_rttin_range &&
14710 	    (rack->r_ctl.rc_last_us_rtt >=
14711 	     (get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack->rtt_limit_mul))) {
14712 		/* The rtt is huge, N * smallest, lets not fill */
14713 		return (slot);
14714 	}
14715 	/*
14716 	 * first lets calculate the b/w based on the last us-rtt
14717 	 * and the sndwnd.
14718 	 */
14719 	fill_bw = rack->r_ctl.cwnd_to_use;
14720 	/* Take the rwnd if its smaller */
14721 	if (fill_bw > rack->rc_tp->snd_wnd)
14722 		fill_bw = rack->rc_tp->snd_wnd;
14723 	if (rack->r_fill_less_agg) {
14724 		/*
14725 		 * Now take away the inflight (this will reduce our
14726 		 * aggressiveness and yeah, if we get that much out in 1RTT
14727 		 * we will have had acks come back and still be behind).
14728 		 */
14729 		fill_bw -= ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
14730 	}
14731 	/* Now lets make it into a b/w */
14732 	fill_bw *= (uint64_t)HPTS_USEC_IN_SEC;
14733 	fill_bw /= (uint64_t)rack->r_ctl.rc_last_us_rtt;
14734 	/* We are below the min b/w */
14735 	if (non_paced)
14736 		*rate_wanted = fill_bw;
14737 	if ((fill_bw < RACK_MIN_BW) || (fill_bw < *rate_wanted))
14738 		return (slot);
14739 	if (rack->r_ctl.bw_rate_cap && (fill_bw > rack->r_ctl.bw_rate_cap))
14740 		fill_bw = rack->r_ctl.bw_rate_cap;
14741 	rack->r_via_fill_cw = 1;
14742 	if (rack->r_rack_hw_rate_caps &&
14743 	    (rack->r_ctl.crte != NULL)) {
14744 		uint64_t high_rate;
14745 
14746 		high_rate = tcp_hw_highest_rate(rack->r_ctl.crte);
14747 		if (fill_bw > high_rate) {
14748 			/* We are capping bw at the highest rate table entry */
14749 			if (*rate_wanted > high_rate) {
14750 				/* The original rate was also capped */
14751 				rack->r_via_fill_cw = 0;
14752 			}
14753 			rack_log_hdwr_pacing(rack,
14754 					     fill_bw, high_rate, __LINE__,
14755 					     0, 3);
14756 			fill_bw = high_rate;
14757 			if (capped)
14758 				*capped = 1;
14759 		}
14760 	} else if ((rack->r_ctl.crte == NULL) &&
14761 		   (rack->rack_hdrw_pacing == 0) &&
14762 		   (rack->rack_hdw_pace_ena) &&
14763 		   rack->r_rack_hw_rate_caps &&
14764 		   (rack->rack_attempt_hdwr_pace == 0) &&
14765 		   (rack->rc_inp->inp_route.ro_nh != NULL) &&
14766 		   (rack->rc_inp->inp_route.ro_nh->nh_ifp != NULL)) {
14767 		/*
14768 		 * Ok we may have a first attempt that is greater than our top rate
14769 		 * lets check.
14770 		 */
14771 		uint64_t high_rate;
14772 
14773 		high_rate = tcp_hw_highest_rate_ifp(rack->rc_inp->inp_route.ro_nh->nh_ifp, rack->rc_inp);
14774 		if (high_rate) {
14775 			if (fill_bw > high_rate) {
14776 				fill_bw = high_rate;
14777 				if (capped)
14778 					*capped = 1;
14779 			}
14780 		}
14781 	}
14782 	/*
14783 	 * Ok fill_bw holds our mythical b/w to fill the cwnd
14784 	 * in a rtt, what does that time wise equate too?
14785 	 */
14786 	lentim = (uint64_t)(len) * (uint64_t)HPTS_USEC_IN_SEC;
14787 	lentim /= fill_bw;
14788 	*rate_wanted = fill_bw;
14789 	if (non_paced || (lentim < slot)) {
14790 		rack_log_pacing_delay_calc(rack, len, slot, fill_bw,
14791 					   0, lentim, 12, __LINE__, NULL, 0);
14792 		return ((int32_t)lentim);
14793 	} else
14794 		return (slot);
14795 }
14796 
14797 static int32_t
14798 rack_get_pacing_delay(struct tcp_rack *rack, struct tcpcb *tp, uint32_t len, struct rack_sendmap *rsm, uint32_t segsiz)
14799 {
14800 	uint64_t srtt;
14801 	int32_t slot = 0;
14802 	int can_start_hw_pacing = 1;
14803 	int err;
14804 
14805 	if (rack->rc_always_pace == 0) {
14806 		/*
14807 		 * We use the most optimistic possible cwnd/srtt for
14808 		 * sending calculations. This will make our
14809 		 * calculation anticipate getting more through
14810 		 * quicker then possible. But thats ok we don't want
14811 		 * the peer to have a gap in data sending.
14812 		 */
14813 		uint64_t cwnd, tr_perms = 0;
14814 		int32_t reduce = 0;
14815 
14816 	old_method:
14817 		/*
14818 		 * We keep no precise pacing with the old method
14819 		 * instead we use the pacer to mitigate bursts.
14820 		 */
14821 		if (rack->r_ctl.rc_rack_min_rtt)
14822 			srtt = rack->r_ctl.rc_rack_min_rtt;
14823 		else
14824 			srtt = max(tp->t_srtt, 1);
14825 		if (rack->r_ctl.rc_rack_largest_cwnd)
14826 			cwnd = rack->r_ctl.rc_rack_largest_cwnd;
14827 		else
14828 			cwnd = rack->r_ctl.cwnd_to_use;
14829 		/* Inflate cwnd by 1000 so srtt of usecs is in ms */
14830 		tr_perms = (cwnd * 1000) / srtt;
14831 		if (tr_perms == 0) {
14832 			tr_perms = ctf_fixed_maxseg(tp);
14833 		}
14834 		/*
14835 		 * Calculate how long this will take to drain, if
14836 		 * the calculation comes out to zero, thats ok we
14837 		 * will use send_a_lot to possibly spin around for
14838 		 * more increasing tot_len_this_send to the point
14839 		 * that its going to require a pace, or we hit the
14840 		 * cwnd. Which in that case we are just waiting for
14841 		 * a ACK.
14842 		 */
14843 		slot = len / tr_perms;
14844 		/* Now do we reduce the time so we don't run dry? */
14845 		if (slot && rack_slot_reduction) {
14846 			reduce = (slot / rack_slot_reduction);
14847 			if (reduce < slot) {
14848 				slot -= reduce;
14849 			} else
14850 				slot = 0;
14851 		}
14852 		slot *= HPTS_USEC_IN_MSEC;
14853 		if (rack->rc_pace_to_cwnd) {
14854 			uint64_t rate_wanted = 0;
14855 
14856 			slot = pace_to_fill_cwnd(rack, slot, len, segsiz, NULL, &rate_wanted, 1);
14857 			rack->rc_ack_can_sendout_data = 1;
14858 			rack_log_pacing_delay_calc(rack, len, slot, rate_wanted, 0, 0, 14, __LINE__, NULL, 0);
14859 		} else
14860 			rack_log_pacing_delay_calc(rack, len, slot, tr_perms, reduce, 0, 7, __LINE__, NULL, 0);
14861 	} else {
14862 		uint64_t bw_est, res, lentim, rate_wanted;
14863 		uint32_t orig_val, segs, oh;
14864 		int capped = 0;
14865 		int prev_fill;
14866 
14867 		if ((rack->r_rr_config == 1) && rsm) {
14868 			return (rack->r_ctl.rc_min_to);
14869 		}
14870 		if (rack->use_fixed_rate) {
14871 			rate_wanted = bw_est = rack_get_fixed_pacing_bw(rack);
14872 		} else if ((rack->r_ctl.init_rate == 0) &&
14873 #ifdef NETFLIX_PEAKRATE
14874 			   (rack->rc_tp->t_maxpeakrate == 0) &&
14875 #endif
14876 			   (rack->r_ctl.gp_bw == 0)) {
14877 			/* no way to yet do an estimate */
14878 			bw_est = rate_wanted = 0;
14879 		} else {
14880 			bw_est = rack_get_bw(rack);
14881 			rate_wanted = rack_get_output_bw(rack, bw_est, rsm, &capped);
14882 		}
14883 		if ((bw_est == 0) || (rate_wanted == 0) ||
14884 		    ((rack->gp_ready == 0) && (rack->use_fixed_rate == 0))) {
14885 			/*
14886 			 * No way yet to make a b/w estimate or
14887 			 * our raise is set incorrectly.
14888 			 */
14889 			goto old_method;
14890 		}
14891 		/* We need to account for all the overheads */
14892 		segs = (len + segsiz - 1) / segsiz;
14893 		/*
14894 		 * We need the diff between 1514 bytes (e-mtu with e-hdr)
14895 		 * and how much data we put in each packet. Yes this
14896 		 * means we may be off if we are larger than 1500 bytes
14897 		 * or smaller. But this just makes us more conservative.
14898 		 */
14899 		if (rack_hw_rate_min &&
14900 		    (bw_est < rack_hw_rate_min))
14901 			can_start_hw_pacing = 0;
14902 		if (ETHERNET_SEGMENT_SIZE > segsiz)
14903 			oh = ETHERNET_SEGMENT_SIZE - segsiz;
14904 		else
14905 			oh = 0;
14906 		segs *= oh;
14907 		lentim = (uint64_t)(len + segs) * (uint64_t)HPTS_USEC_IN_SEC;
14908 		res = lentim / rate_wanted;
14909 		slot = (uint32_t)res;
14910 		orig_val = rack->r_ctl.rc_pace_max_segs;
14911 		if (rack->r_ctl.crte == NULL) {
14912 			/*
14913 			 * Only do this if we are not hardware pacing
14914 			 * since if we are doing hw-pacing below we will
14915 			 * set make a call after setting up or changing
14916 			 * the rate.
14917 			 */
14918 			rack_set_pace_segments(rack->rc_tp, rack, __LINE__, NULL);
14919 		} else if (rack->rc_inp->inp_snd_tag == NULL) {
14920 			/*
14921 			 * We lost our rate somehow, this can happen
14922 			 * if the interface changed underneath us.
14923 			 */
14924 			tcp_rel_pacing_rate(rack->r_ctl.crte, rack->rc_tp);
14925 			rack->r_ctl.crte = NULL;
14926 			/* Lets re-allow attempting to setup pacing */
14927 			rack->rack_hdrw_pacing = 0;
14928 			rack->rack_attempt_hdwr_pace = 0;
14929 			rack_log_hdwr_pacing(rack,
14930 					     rate_wanted, bw_est, __LINE__,
14931 					     0, 6);
14932 		}
14933 		/* Did we change the TSO size, if so log it */
14934 		if (rack->r_ctl.rc_pace_max_segs != orig_val)
14935 			rack_log_pacing_delay_calc(rack, len, slot, orig_val, 0, 0, 15, __LINE__, NULL, 0);
14936 		prev_fill = rack->r_via_fill_cw;
14937 		if ((rack->rc_pace_to_cwnd) &&
14938 		    (capped == 0) &&
14939 		    (rack->use_fixed_rate == 0) &&
14940 		    (rack->in_probe_rtt == 0) &&
14941 		    (IN_FASTRECOVERY(rack->rc_tp->t_flags) == 0)) {
14942 			/*
14943 			 * We want to pace at our rate *or* faster to
14944 			 * fill the cwnd to the max if its not full.
14945 			 */
14946 			slot = pace_to_fill_cwnd(rack, slot, (len+segs), segsiz, &capped, &rate_wanted, 0);
14947 		}
14948 		if ((rack->rc_inp->inp_route.ro_nh != NULL) &&
14949 		    (rack->rc_inp->inp_route.ro_nh->nh_ifp != NULL)) {
14950 			if ((rack->rack_hdw_pace_ena) &&
14951 			    (can_start_hw_pacing > 0) &&
14952 			    (rack->rack_hdrw_pacing == 0) &&
14953 			    (rack->rack_attempt_hdwr_pace == 0)) {
14954 				/*
14955 				 * Lets attempt to turn on hardware pacing
14956 				 * if we can.
14957 				 */
14958 				rack->rack_attempt_hdwr_pace = 1;
14959 				rack->r_ctl.crte = tcp_set_pacing_rate(rack->rc_tp,
14960 								       rack->rc_inp->inp_route.ro_nh->nh_ifp,
14961 								       rate_wanted,
14962 								       RS_PACING_GEQ,
14963 								       &err, &rack->r_ctl.crte_prev_rate);
14964 				if (rack->r_ctl.crte) {
14965 					rack->rack_hdrw_pacing = 1;
14966 					rack->r_ctl.rc_pace_max_segs = tcp_get_pacing_burst_size(tp, rate_wanted, segsiz,
14967 												 0, rack->r_ctl.crte,
14968 												 NULL);
14969 					rack_log_hdwr_pacing(rack,
14970 							     rate_wanted, rack->r_ctl.crte->rate, __LINE__,
14971 							     err, 0);
14972 					rack->r_ctl.last_hw_bw_req = rate_wanted;
14973 				} else {
14974 					counter_u64_add(rack_hw_pace_init_fail, 1);
14975 				}
14976 			} else if (rack->rack_hdrw_pacing &&
14977 				   (rack->r_ctl.last_hw_bw_req != rate_wanted)) {
14978 				/* Do we need to adjust our rate? */
14979 				const struct tcp_hwrate_limit_table *nrte;
14980 
14981 				if (rack->r_up_only &&
14982 				    (rate_wanted < rack->r_ctl.crte->rate)) {
14983 					/**
14984 					 * We have four possible states here
14985 					 * having to do with the previous time
14986 					 * and this time.
14987 					 *   previous  |  this-time
14988 					 * A)     0      |     0   -- fill_cw not in the picture
14989 					 * B)     1      |     0   -- we were doing a fill-cw but now are not
14990 					 * C)     1      |     1   -- all rates from fill_cw
14991 					 * D)     0      |     1   -- we were doing non-fill and now we are filling
14992 					 *
14993 					 * For case A, C and D we don't allow a drop. But for
14994 					 * case B where we now our on our steady rate we do
14995 					 * allow a drop.
14996 					 *
14997 					 */
14998 					if (!((prev_fill == 1) && (rack->r_via_fill_cw == 0)))
14999 						goto done_w_hdwr;
15000 				}
15001 				if ((rate_wanted > rack->r_ctl.crte->rate) ||
15002 				    (rate_wanted <= rack->r_ctl.crte_prev_rate)) {
15003 					if (rack_hw_rate_to_low &&
15004 					    (bw_est < rack_hw_rate_to_low)) {
15005 						/*
15006 						 * The pacing rate is too low for hardware, but
15007 						 * do allow hardware pacing to be restarted.
15008 						 */
15009 						rack_log_hdwr_pacing(rack,
15010 							     bw_est, rack->r_ctl.crte->rate, __LINE__,
15011 							     0, 5);
15012 						tcp_rel_pacing_rate(rack->r_ctl.crte, rack->rc_tp);
15013 						rack->r_ctl.crte = NULL;
15014 						rack->rack_attempt_hdwr_pace = 0;
15015 						rack->rack_hdrw_pacing = 0;
15016 						rack_set_pace_segments(rack->rc_tp, rack, __LINE__, &rate_wanted);
15017 						goto done_w_hdwr;
15018 					}
15019 					nrte = tcp_chg_pacing_rate(rack->r_ctl.crte,
15020 								   rack->rc_tp,
15021 								   rack->rc_inp->inp_route.ro_nh->nh_ifp,
15022 								   rate_wanted,
15023 								   RS_PACING_GEQ,
15024 								   &err, &rack->r_ctl.crte_prev_rate);
15025 					if (nrte == NULL) {
15026 						/* Lost the rate */
15027 						rack->rack_hdrw_pacing = 0;
15028 						rack->r_ctl.crte = NULL;
15029 						rack_log_hdwr_pacing(rack,
15030 								     rate_wanted, 0, __LINE__,
15031 								     err, 1);
15032 						rack_set_pace_segments(rack->rc_tp, rack, __LINE__, &rate_wanted);
15033 						counter_u64_add(rack_hw_pace_lost, 1);
15034 					} else if (nrte != rack->r_ctl.crte) {
15035 						rack->r_ctl.crte = nrte;
15036 						rack->r_ctl.rc_pace_max_segs = tcp_get_pacing_burst_size(tp, rate_wanted,
15037 													 segsiz, 0,
15038 													 rack->r_ctl.crte,
15039 													 NULL);
15040 						rack_log_hdwr_pacing(rack,
15041 								     rate_wanted, rack->r_ctl.crte->rate, __LINE__,
15042 								     err, 2);
15043 						rack->r_ctl.last_hw_bw_req = rate_wanted;
15044 					}
15045 				} else {
15046 					/* We just need to adjust the segment size */
15047 					rack_set_pace_segments(rack->rc_tp, rack, __LINE__, &rate_wanted);
15048 					rack_log_hdwr_pacing(rack,
15049 							     rate_wanted, rack->r_ctl.crte->rate, __LINE__,
15050 							     0, 4);
15051 					rack->r_ctl.last_hw_bw_req = rate_wanted;
15052 				}
15053 			}
15054 		}
15055 		if ((rack->r_ctl.crte != NULL) &&
15056 		    (rack->r_ctl.crte->rate == rate_wanted)) {
15057 			/*
15058 			 * We need to add a extra if the rates
15059 			 * are exactly matched. The idea is
15060 			 * we want the software to make sure the
15061 			 * queue is empty before adding more, this
15062 			 * gives us N MSS extra pace times where
15063 			 * N is our sysctl
15064 			 */
15065 			slot += (rack->r_ctl.crte->time_between * rack_hw_pace_extra_slots);
15066 		}
15067 done_w_hdwr:
15068 		if (rack_limit_time_with_srtt &&
15069 		    (rack->use_fixed_rate == 0) &&
15070 #ifdef NETFLIX_PEAKRATE
15071 		    (rack->rc_tp->t_maxpeakrate == 0) &&
15072 #endif
15073 		    (rack->rack_hdrw_pacing == 0)) {
15074 			/*
15075 			 * Sanity check, we do not allow the pacing delay
15076 			 * to be longer than the SRTT of the path. If it is
15077 			 * a slow path, then adding a packet should increase
15078 			 * the RTT and compensate for this i.e. the srtt will
15079 			 * be greater so the allowed pacing time will be greater.
15080 			 *
15081 			 * Note this restriction is not for where a peak rate
15082 			 * is set, we are doing fixed pacing or hardware pacing.
15083 			 */
15084 			if (rack->rc_tp->t_srtt)
15085 				srtt = rack->rc_tp->t_srtt;
15086 			else
15087 				srtt = RACK_INITIAL_RTO * HPTS_USEC_IN_MSEC;	/* its in ms convert */
15088 			if (srtt < (uint64_t)slot) {
15089 				rack_log_pacing_delay_calc(rack, srtt, slot, rate_wanted, bw_est, lentim, 99, __LINE__, NULL, 0);
15090 				slot = srtt;
15091 			}
15092 		}
15093 		rack_log_pacing_delay_calc(rack, len, slot, rate_wanted, bw_est, lentim, 2, __LINE__, rsm, 0);
15094 	}
15095 	if (rack->r_ctl.crte && (rack->r_ctl.crte->rs_num_enobufs > 0)) {
15096 		/*
15097 		 * If this rate is seeing enobufs when it
15098 		 * goes to send then either the nic is out
15099 		 * of gas or we are mis-estimating the time
15100 		 * somehow and not letting the queue empty
15101 		 * completely. Lets add to the pacing time.
15102 		 */
15103 		int hw_boost_delay;
15104 
15105 		hw_boost_delay = rack->r_ctl.crte->time_between * rack_enobuf_hw_boost_mult;
15106 		if (hw_boost_delay > rack_enobuf_hw_max)
15107 			hw_boost_delay = rack_enobuf_hw_max;
15108 		else if (hw_boost_delay < rack_enobuf_hw_min)
15109 			hw_boost_delay = rack_enobuf_hw_min;
15110 		slot += hw_boost_delay;
15111 	}
15112 	return (slot);
15113 }
15114 
15115 static void
15116 rack_start_gp_measurement(struct tcpcb *tp, struct tcp_rack *rack,
15117     tcp_seq startseq, uint32_t sb_offset)
15118 {
15119 	struct rack_sendmap *my_rsm = NULL;
15120 	struct rack_sendmap fe;
15121 
15122 	if (tp->t_state < TCPS_ESTABLISHED) {
15123 		/*
15124 		 * We don't start any measurements if we are
15125 		 * not at least established.
15126 		 */
15127 		return;
15128 	}
15129 	if (tp->t_state >= TCPS_FIN_WAIT_1) {
15130 		/*
15131 		 * We will get no more data into the SB
15132 		 * this means we need to have the data available
15133 		 * before we start a measurement.
15134 		 */
15135 
15136 		if (sbavail(&tptosocket(tp)->so_snd) <
15137 		    max(rc_init_window(rack),
15138 			(MIN_GP_WIN * ctf_fixed_maxseg(tp)))) {
15139 			/* Nope not enough data */
15140 			return;
15141 		}
15142 	}
15143 	tp->t_flags |= TF_GPUTINPROG;
15144 	rack->r_ctl.rc_gp_lowrtt = 0xffffffff;
15145 	rack->r_ctl.rc_gp_high_rwnd = rack->rc_tp->snd_wnd;
15146 	tp->gput_seq = startseq;
15147 	rack->app_limited_needs_set = 0;
15148 	if (rack->in_probe_rtt)
15149 		rack->measure_saw_probe_rtt = 1;
15150 	else if ((rack->measure_saw_probe_rtt) &&
15151 		 (SEQ_GEQ(tp->gput_seq, rack->r_ctl.rc_probertt_sndmax_atexit)))
15152 		rack->measure_saw_probe_rtt = 0;
15153 	if (rack->rc_gp_filled)
15154 		tp->gput_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
15155 	else {
15156 		/* Special case initial measurement */
15157 		struct timeval tv;
15158 
15159 		tp->gput_ts = tcp_get_usecs(&tv);
15160 		rack->r_ctl.rc_gp_output_ts = rack_to_usec_ts(&tv);
15161 	}
15162 	/*
15163 	 * We take a guess out into the future,
15164 	 * if we have no measurement and no
15165 	 * initial rate, we measure the first
15166 	 * initial-windows worth of data to
15167 	 * speed up getting some GP measurement and
15168 	 * thus start pacing.
15169 	 */
15170 	if ((rack->rc_gp_filled == 0) && (rack->r_ctl.init_rate == 0)) {
15171 		rack->app_limited_needs_set = 1;
15172 		tp->gput_ack = startseq + max(rc_init_window(rack),
15173 					      (MIN_GP_WIN * ctf_fixed_maxseg(tp)));
15174 		rack_log_pacing_delay_calc(rack,
15175 					   tp->gput_seq,
15176 					   tp->gput_ack,
15177 					   0,
15178 					   tp->gput_ts,
15179 					   rack->r_ctl.rc_app_limited_cnt,
15180 					   9,
15181 					   __LINE__, NULL, 0);
15182 		return;
15183 	}
15184 	if (sb_offset) {
15185 		/*
15186 		 * We are out somewhere in the sb
15187 		 * can we use the already outstanding data?
15188 		 */
15189 		if (rack->r_ctl.rc_app_limited_cnt == 0) {
15190 			/*
15191 			 * Yes first one is good and in this case
15192 			 * the tp->gput_ts is correctly set based on
15193 			 * the last ack that arrived (no need to
15194 			 * set things up when an ack comes in).
15195 			 */
15196 			my_rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
15197 			if ((my_rsm == NULL) ||
15198 			    (my_rsm->r_rtr_cnt != 1)) {
15199 				/* retransmission? */
15200 				goto use_latest;
15201 			}
15202 		} else {
15203 			if (rack->r_ctl.rc_first_appl == NULL) {
15204 				/*
15205 				 * If rc_first_appl is NULL
15206 				 * then the cnt should be 0.
15207 				 * This is probably an error, maybe
15208 				 * a KASSERT would be approprate.
15209 				 */
15210 				goto use_latest;
15211 			}
15212 			/*
15213 			 * If we have a marker pointer to the last one that is
15214 			 * app limited we can use that, but we need to set
15215 			 * things up so that when it gets ack'ed we record
15216 			 * the ack time (if its not already acked).
15217 			 */
15218 			rack->app_limited_needs_set = 1;
15219 			/*
15220 			 * We want to get to the rsm that is either
15221 			 * next with space i.e. over 1 MSS or the one
15222 			 * after that (after the app-limited).
15223 			 */
15224 			my_rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree,
15225 					 rack->r_ctl.rc_first_appl);
15226 			if (my_rsm) {
15227 				if ((my_rsm->r_end - my_rsm->r_start) <= ctf_fixed_maxseg(tp))
15228 					/* Have to use the next one */
15229 					my_rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree,
15230 							 my_rsm);
15231 				else {
15232 					/* Use after the first MSS of it is acked */
15233 					tp->gput_seq = my_rsm->r_start + ctf_fixed_maxseg(tp);
15234 					goto start_set;
15235 				}
15236 			}
15237 			if ((my_rsm == NULL) ||
15238 			    (my_rsm->r_rtr_cnt != 1)) {
15239 				/*
15240 				 * Either its a retransmit or
15241 				 * the last is the app-limited one.
15242 				 */
15243 				goto use_latest;
15244 			}
15245 		}
15246 		tp->gput_seq = my_rsm->r_start;
15247 start_set:
15248 		if (my_rsm->r_flags & RACK_ACKED) {
15249 			/*
15250 			 * This one has been acked use the arrival ack time
15251 			 */
15252 			tp->gput_ts = (uint32_t)my_rsm->r_ack_arrival;
15253 			rack->app_limited_needs_set = 0;
15254 		}
15255 		rack->r_ctl.rc_gp_output_ts = my_rsm->r_tim_lastsent[(my_rsm->r_rtr_cnt-1)];
15256 		tp->gput_ack = tp->gput_seq + rack_get_measure_window(tp, rack);
15257 		rack_log_pacing_delay_calc(rack,
15258 					   tp->gput_seq,
15259 					   tp->gput_ack,
15260 					   (uint64_t)my_rsm,
15261 					   tp->gput_ts,
15262 					   rack->r_ctl.rc_app_limited_cnt,
15263 					   9,
15264 					   __LINE__, NULL, 0);
15265 		return;
15266 	}
15267 
15268 use_latest:
15269 	/*
15270 	 * We don't know how long we may have been
15271 	 * idle or if this is the first-send. Lets
15272 	 * setup the flag so we will trim off
15273 	 * the first ack'd data so we get a true
15274 	 * measurement.
15275 	 */
15276 	rack->app_limited_needs_set = 1;
15277 	tp->gput_ack = startseq + rack_get_measure_window(tp, rack);
15278 	/* Find this guy so we can pull the send time */
15279 	fe.r_start = startseq;
15280 	my_rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
15281 	if (my_rsm) {
15282 		rack->r_ctl.rc_gp_output_ts = my_rsm->r_tim_lastsent[(my_rsm->r_rtr_cnt-1)];
15283 		if (my_rsm->r_flags & RACK_ACKED) {
15284 			/*
15285 			 * Unlikely since its probably what was
15286 			 * just transmitted (but I am paranoid).
15287 			 */
15288 			tp->gput_ts = (uint32_t)my_rsm->r_ack_arrival;
15289 			rack->app_limited_needs_set = 0;
15290 		}
15291 		if (SEQ_LT(my_rsm->r_start, tp->gput_seq)) {
15292 			/* This also is unlikely */
15293 			tp->gput_seq = my_rsm->r_start;
15294 		}
15295 	} else {
15296 		/*
15297 		 * TSNH unless we have some send-map limit,
15298 		 * and even at that it should not be hitting
15299 		 * that limit (we should have stopped sending).
15300 		 */
15301 		struct timeval tv;
15302 
15303 		microuptime(&tv);
15304 		rack->r_ctl.rc_gp_output_ts = rack_to_usec_ts(&tv);
15305 	}
15306 	rack_log_pacing_delay_calc(rack,
15307 				   tp->gput_seq,
15308 				   tp->gput_ack,
15309 				   (uint64_t)my_rsm,
15310 				   tp->gput_ts,
15311 				   rack->r_ctl.rc_app_limited_cnt,
15312 				   9, __LINE__, NULL, 0);
15313 }
15314 
15315 static inline uint32_t
15316 rack_what_can_we_send(struct tcpcb *tp, struct tcp_rack *rack,  uint32_t cwnd_to_use,
15317     uint32_t avail, int32_t sb_offset)
15318 {
15319 	uint32_t len;
15320 	uint32_t sendwin;
15321 
15322 	if (tp->snd_wnd > cwnd_to_use)
15323 		sendwin = cwnd_to_use;
15324 	else
15325 		sendwin = tp->snd_wnd;
15326 	if (ctf_outstanding(tp) >= tp->snd_wnd) {
15327 		/* We never want to go over our peers rcv-window */
15328 		len = 0;
15329 	} else {
15330 		uint32_t flight;
15331 
15332 		flight = ctf_flight_size(tp, rack->r_ctl.rc_sacked);
15333 		if (flight >= sendwin) {
15334 			/*
15335 			 * We have in flight what we are allowed by cwnd (if
15336 			 * it was rwnd blocking it would have hit above out
15337 			 * >= tp->snd_wnd).
15338 			 */
15339 			return (0);
15340 		}
15341 		len = sendwin - flight;
15342 		if ((len + ctf_outstanding(tp)) > tp->snd_wnd) {
15343 			/* We would send too much (beyond the rwnd) */
15344 			len = tp->snd_wnd - ctf_outstanding(tp);
15345 		}
15346 		if ((len + sb_offset) > avail) {
15347 			/*
15348 			 * We don't have that much in the SB, how much is
15349 			 * there?
15350 			 */
15351 			len = avail - sb_offset;
15352 		}
15353 	}
15354 	return (len);
15355 }
15356 
15357 static void
15358 rack_log_fsb(struct tcp_rack *rack, struct tcpcb *tp, struct socket *so, uint32_t flags,
15359 	     unsigned ipoptlen, int32_t orig_len, int32_t len, int error,
15360 	     int rsm_is_null, int optlen, int line, uint16_t mode)
15361 {
15362 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
15363 		union tcp_log_stackspecific log;
15364 		struct timeval tv;
15365 
15366 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
15367 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
15368 		log.u_bbr.flex1 = error;
15369 		log.u_bbr.flex2 = flags;
15370 		log.u_bbr.flex3 = rsm_is_null;
15371 		log.u_bbr.flex4 = ipoptlen;
15372 		log.u_bbr.flex5 = tp->rcv_numsacks;
15373 		log.u_bbr.flex6 = rack->r_ctl.rc_agg_early;
15374 		log.u_bbr.flex7 = optlen;
15375 		log.u_bbr.flex8 = rack->r_fsb_inited;
15376 		log.u_bbr.applimited = rack->r_fast_output;
15377 		log.u_bbr.bw_inuse = rack_get_bw(rack);
15378 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, NULL);
15379 		log.u_bbr.cwnd_gain = mode;
15380 		log.u_bbr.pkts_out = orig_len;
15381 		log.u_bbr.lt_epoch = len;
15382 		log.u_bbr.delivered = line;
15383 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
15384 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
15385 		tcp_log_event_(tp, NULL, &so->so_rcv, &so->so_snd, TCP_LOG_FSB, 0,
15386 			       len, &log, false, NULL, NULL, 0, &tv);
15387 	}
15388 }
15389 
15390 
15391 static struct mbuf *
15392 rack_fo_base_copym(struct mbuf *the_m, uint32_t the_off, int32_t *plen,
15393 		   struct rack_fast_send_blk *fsb,
15394 		   int32_t seglimit, int32_t segsize, int hw_tls)
15395 {
15396 #ifdef KERN_TLS
15397 	struct ktls_session *tls, *ntls;
15398 #ifdef INVARIANTS
15399 	struct mbuf *start;
15400 #endif
15401 #endif
15402 	struct mbuf *m, *n, **np, *smb;
15403 	struct mbuf *top;
15404 	int32_t off, soff;
15405 	int32_t len = *plen;
15406 	int32_t fragsize;
15407 	int32_t len_cp = 0;
15408 	uint32_t mlen, frags;
15409 
15410 	soff = off = the_off;
15411 	smb = m = the_m;
15412 	np = &top;
15413 	top = NULL;
15414 #ifdef KERN_TLS
15415 	if (hw_tls && (m->m_flags & M_EXTPG))
15416 		tls = m->m_epg_tls;
15417 	else
15418 		tls = NULL;
15419 #ifdef INVARIANTS
15420 	start = m;
15421 #endif
15422 #endif
15423 	while (len > 0) {
15424 		if (m == NULL) {
15425 			*plen = len_cp;
15426 			break;
15427 		}
15428 #ifdef KERN_TLS
15429 		if (hw_tls) {
15430 			if (m->m_flags & M_EXTPG)
15431 				ntls = m->m_epg_tls;
15432 			else
15433 				ntls = NULL;
15434 
15435 			/*
15436 			 * Avoid mixing TLS records with handshake
15437 			 * data or TLS records from different
15438 			 * sessions.
15439 			 */
15440 			if (tls != ntls) {
15441 				MPASS(m != start);
15442 				*plen = len_cp;
15443 				break;
15444 			}
15445 		}
15446 #endif
15447 		mlen = min(len, m->m_len - off);
15448 		if (seglimit) {
15449 			/*
15450 			 * For M_EXTPG mbufs, add 3 segments
15451 			 * + 1 in case we are crossing page boundaries
15452 			 * + 2 in case the TLS hdr/trailer are used
15453 			 * It is cheaper to just add the segments
15454 			 * than it is to take the cache miss to look
15455 			 * at the mbuf ext_pgs state in detail.
15456 			 */
15457 			if (m->m_flags & M_EXTPG) {
15458 				fragsize = min(segsize, PAGE_SIZE);
15459 				frags = 3;
15460 			} else {
15461 				fragsize = segsize;
15462 				frags = 0;
15463 			}
15464 
15465 			/* Break if we really can't fit anymore. */
15466 			if ((frags + 1) >= seglimit) {
15467 				*plen =	len_cp;
15468 				break;
15469 			}
15470 
15471 			/*
15472 			 * Reduce size if you can't copy the whole
15473 			 * mbuf. If we can't copy the whole mbuf, also
15474 			 * adjust len so the loop will end after this
15475 			 * mbuf.
15476 			 */
15477 			if ((frags + howmany(mlen, fragsize)) >= seglimit) {
15478 				mlen = (seglimit - frags - 1) * fragsize;
15479 				len = mlen;
15480 				*plen = len_cp + len;
15481 			}
15482 			frags += howmany(mlen, fragsize);
15483 			if (frags == 0)
15484 				frags++;
15485 			seglimit -= frags;
15486 			KASSERT(seglimit > 0,
15487 			    ("%s: seglimit went too low", __func__));
15488 		}
15489 		n = m_get(M_NOWAIT, m->m_type);
15490 		*np = n;
15491 		if (n == NULL)
15492 			goto nospace;
15493 		n->m_len = mlen;
15494 		soff += mlen;
15495 		len_cp += n->m_len;
15496 		if (m->m_flags & (M_EXT|M_EXTPG)) {
15497 			n->m_data = m->m_data + off;
15498 			mb_dupcl(n, m);
15499 		} else {
15500 			bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
15501 			    (u_int)n->m_len);
15502 		}
15503 		len -= n->m_len;
15504 		off = 0;
15505 		m = m->m_next;
15506 		np = &n->m_next;
15507 		if (len || (soff == smb->m_len)) {
15508 			/*
15509 			 * We have more so we move forward  or
15510 			 * we have consumed the entire mbuf and
15511 			 * len has fell to 0.
15512 			 */
15513 			soff = 0;
15514 			smb = m;
15515 		}
15516 
15517 	}
15518 	if (fsb != NULL) {
15519 		fsb->m = smb;
15520 		fsb->off = soff;
15521 		if (smb) {
15522 			/*
15523 			 * Save off the size of the mbuf. We do
15524 			 * this so that we can recognize when it
15525 			 * has been trimmed by sbcut() as acks
15526 			 * come in.
15527 			 */
15528 			fsb->o_m_len = smb->m_len;
15529 		} else {
15530 			/*
15531 			 * This is the case where the next mbuf went to NULL. This
15532 			 * means with this copy we have sent everything in the sb.
15533 			 * In theory we could clear the fast_output flag, but lets
15534 			 * not since its possible that we could get more added
15535 			 * and acks that call the extend function which would let
15536 			 * us send more.
15537 			 */
15538 			fsb->o_m_len = 0;
15539 		}
15540 	}
15541 	return (top);
15542 nospace:
15543 	if (top)
15544 		m_freem(top);
15545 	return (NULL);
15546 
15547 }
15548 
15549 /*
15550  * This is a copy of m_copym(), taking the TSO segment size/limit
15551  * constraints into account, and advancing the sndptr as it goes.
15552  */
15553 static struct mbuf *
15554 rack_fo_m_copym(struct tcp_rack *rack, int32_t *plen,
15555 		int32_t seglimit, int32_t segsize, struct mbuf **s_mb, int *s_soff)
15556 {
15557 	struct mbuf *m, *n;
15558 	int32_t soff;
15559 
15560 	soff = rack->r_ctl.fsb.off;
15561 	m = rack->r_ctl.fsb.m;
15562 	if (rack->r_ctl.fsb.o_m_len > m->m_len) {
15563 		/*
15564 		 * The mbuf had the front of it chopped off by an ack
15565 		 * we need to adjust the soff/off by that difference.
15566 		 */
15567 		uint32_t delta;
15568 
15569 		delta = rack->r_ctl.fsb.o_m_len - m->m_len;
15570 		soff -= delta;
15571 	} else if (rack->r_ctl.fsb.o_m_len < m->m_len) {
15572 		/*
15573 		 * The mbuf was expanded probably by
15574 		 * a m_compress. Just update o_m_len.
15575 		 */
15576 		rack->r_ctl.fsb.o_m_len = m->m_len;
15577 	}
15578 	KASSERT(soff >= 0, ("%s, negative off %d", __FUNCTION__, soff));
15579 	KASSERT(*plen >= 0, ("%s, negative len %d", __FUNCTION__, *plen));
15580 	KASSERT(soff < m->m_len, ("%s rack:%p len:%u m:%p m->m_len:%u < off?",
15581 				 __FUNCTION__,
15582 				 rack, *plen, m, m->m_len));
15583 	/* Save off the right location before we copy and advance */
15584 	*s_soff = soff;
15585 	*s_mb = rack->r_ctl.fsb.m;
15586 	n = rack_fo_base_copym(m, soff, plen,
15587 			       &rack->r_ctl.fsb,
15588 			       seglimit, segsize, rack->r_ctl.fsb.hw_tls);
15589 	return (n);
15590 }
15591 
15592 static int
15593 rack_fast_rsm_output(struct tcpcb *tp, struct tcp_rack *rack, struct rack_sendmap *rsm,
15594 		     uint64_t ts_val, uint32_t cts, uint32_t ms_cts, struct timeval *tv, int len, uint8_t doing_tlp)
15595 {
15596 	/*
15597 	 * Enter the fast retransmit path. We are given that a sched_pin is
15598 	 * in place (if accounting is compliled in) and the cycle count taken
15599 	 * at the entry is in the ts_val. The concept her is that the rsm
15600 	 * now holds the mbuf offsets and such so we can directly transmit
15601 	 * without a lot of overhead, the len field is already set for
15602 	 * us to prohibit us from sending too much (usually its 1MSS).
15603 	 */
15604 	struct ip *ip = NULL;
15605 	struct udphdr *udp = NULL;
15606 	struct tcphdr *th = NULL;
15607 	struct mbuf *m = NULL;
15608 	struct inpcb *inp;
15609 	uint8_t *cpto;
15610 	struct tcp_log_buffer *lgb;
15611 #ifdef TCP_ACCOUNTING
15612 	uint64_t crtsc;
15613 	int cnt_thru = 1;
15614 #endif
15615 	struct tcpopt to;
15616 	u_char opt[TCP_MAXOLEN];
15617 	uint32_t hdrlen, optlen;
15618 	int32_t slot, segsiz, max_val, tso = 0, error = 0, ulen = 0;
15619 	uint16_t flags;
15620 	uint32_t if_hw_tsomaxsegcount = 0, startseq;
15621 	uint32_t if_hw_tsomaxsegsize;
15622 
15623 #ifdef INET6
15624 	struct ip6_hdr *ip6 = NULL;
15625 
15626 	if (rack->r_is_v6) {
15627 		ip6 = (struct ip6_hdr *)rack->r_ctl.fsb.tcp_ip_hdr;
15628 		hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
15629 	} else
15630 #endif				/* INET6 */
15631 	{
15632 		ip = (struct ip *)rack->r_ctl.fsb.tcp_ip_hdr;
15633 		hdrlen = sizeof(struct tcpiphdr);
15634 	}
15635 	if (tp->t_port && (V_tcp_udp_tunneling_port == 0)) {
15636 		goto failed;
15637 	}
15638 	if (doing_tlp) {
15639 		/* Its a TLP add the flag, it may already be there but be sure */
15640 		rsm->r_flags |= RACK_TLP;
15641 	} else {
15642 		/* If it was a TLP it is not not on this retransmit */
15643 		rsm->r_flags &= ~RACK_TLP;
15644 	}
15645 	startseq = rsm->r_start;
15646 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
15647 	inp = rack->rc_inp;
15648 	to.to_flags = 0;
15649 	flags = tcp_outflags[tp->t_state];
15650 	if (flags & (TH_SYN|TH_RST)) {
15651 		goto failed;
15652 	}
15653 	if (rsm->r_flags & RACK_HAS_FIN) {
15654 		/* We can't send a FIN here */
15655 		goto failed;
15656 	}
15657 	if (flags & TH_FIN) {
15658 		/* We never send a FIN */
15659 		flags &= ~TH_FIN;
15660 	}
15661 	if (tp->t_flags & TF_RCVD_TSTMP) {
15662 		to.to_tsval = ms_cts + tp->ts_offset;
15663 		to.to_tsecr = tp->ts_recent;
15664 		to.to_flags = TOF_TS;
15665 	}
15666 	optlen = tcp_addoptions(&to, opt);
15667 	hdrlen += optlen;
15668 	udp = rack->r_ctl.fsb.udp;
15669 	if (udp)
15670 		hdrlen += sizeof(struct udphdr);
15671 	if (rack->r_ctl.rc_pace_max_segs)
15672 		max_val = rack->r_ctl.rc_pace_max_segs;
15673 	else if (rack->rc_user_set_max_segs)
15674 		max_val = rack->rc_user_set_max_segs * segsiz;
15675 	else
15676 		max_val = len;
15677 	if ((tp->t_flags & TF_TSO) &&
15678 	    V_tcp_do_tso &&
15679 	    (len > segsiz) &&
15680 	    (tp->t_port == 0))
15681 		tso = 1;
15682 #ifdef INET6
15683 	if (MHLEN < hdrlen + max_linkhdr)
15684 		m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
15685 	else
15686 #endif
15687 		m = m_gethdr(M_NOWAIT, MT_DATA);
15688 	if (m == NULL)
15689 		goto failed;
15690 	m->m_data += max_linkhdr;
15691 	m->m_len = hdrlen;
15692 	th = rack->r_ctl.fsb.th;
15693 	/* Establish the len to send */
15694 	if (len > max_val)
15695 		len = max_val;
15696 	if ((tso) && (len + optlen > tp->t_maxseg)) {
15697 		uint32_t if_hw_tsomax;
15698 		int32_t max_len;
15699 
15700 		/* extract TSO information */
15701 		if_hw_tsomax = tp->t_tsomax;
15702 		if_hw_tsomaxsegcount = tp->t_tsomaxsegcount;
15703 		if_hw_tsomaxsegsize = tp->t_tsomaxsegsize;
15704 		/*
15705 		 * Check if we should limit by maximum payload
15706 		 * length:
15707 		 */
15708 		if (if_hw_tsomax != 0) {
15709 			/* compute maximum TSO length */
15710 			max_len = (if_hw_tsomax - hdrlen -
15711 				   max_linkhdr);
15712 			if (max_len <= 0) {
15713 				goto failed;
15714 			} else if (len > max_len) {
15715 				len = max_len;
15716 			}
15717 		}
15718 		if (len <= segsiz) {
15719 			/*
15720 			 * In case there are too many small fragments don't
15721 			 * use TSO:
15722 			 */
15723 			tso = 0;
15724 		}
15725 	} else {
15726 		tso = 0;
15727 	}
15728 	if ((tso == 0) && (len > segsiz))
15729 		len = segsiz;
15730 	if ((len == 0) ||
15731 	    (len <= MHLEN - hdrlen - max_linkhdr)) {
15732 		goto failed;
15733 	}
15734 	th->th_seq = htonl(rsm->r_start);
15735 	th->th_ack = htonl(tp->rcv_nxt);
15736 	/*
15737 	 * The PUSH bit should only be applied
15738 	 * if the full retransmission is made. If
15739 	 * we are sending less than this is the
15740 	 * left hand edge and should not have
15741 	 * the PUSH bit.
15742 	 */
15743 	if ((rsm->r_flags & RACK_HAD_PUSH) &&
15744 	    (len == (rsm->r_end - rsm->r_start)))
15745 		flags |= TH_PUSH;
15746 	th->th_win = htons((u_short)(rack->r_ctl.fsb.recwin >> tp->rcv_scale));
15747 	if (th->th_win == 0) {
15748 		tp->t_sndzerowin++;
15749 		tp->t_flags |= TF_RXWIN0SENT;
15750 	} else
15751 		tp->t_flags &= ~TF_RXWIN0SENT;
15752 	if (rsm->r_flags & RACK_TLP) {
15753 		/*
15754 		 * TLP should not count in retran count, but
15755 		 * in its own bin
15756 		 */
15757 		counter_u64_add(rack_tlp_retran, 1);
15758 		counter_u64_add(rack_tlp_retran_bytes, len);
15759 	} else {
15760 		tp->t_sndrexmitpack++;
15761 		KMOD_TCPSTAT_INC(tcps_sndrexmitpack);
15762 		KMOD_TCPSTAT_ADD(tcps_sndrexmitbyte, len);
15763 	}
15764 #ifdef STATS
15765 	stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RETXPB,
15766 				 len);
15767 #endif
15768 	if (rsm->m == NULL)
15769 		goto failed;
15770 	if (rsm->orig_m_len != rsm->m->m_len) {
15771 		/* Fix up the orig_m_len and possibly the mbuf offset */
15772 		rack_adjust_orig_mlen(rsm);
15773 	}
15774 	m->m_next = rack_fo_base_copym(rsm->m, rsm->soff, &len, NULL, if_hw_tsomaxsegcount, if_hw_tsomaxsegsize, rsm->r_hw_tls);
15775 	if (len <= segsiz) {
15776 		/*
15777 		 * Must have ran out of mbufs for the copy
15778 		 * shorten it to no longer need tso. Lets
15779 		 * not put on sendalot since we are low on
15780 		 * mbufs.
15781 		 */
15782 		tso = 0;
15783 	}
15784 	if ((m->m_next == NULL) || (len <= 0)){
15785 		goto failed;
15786 	}
15787 	if (udp) {
15788 		if (rack->r_is_v6)
15789 			ulen = hdrlen + len - sizeof(struct ip6_hdr);
15790 		else
15791 			ulen = hdrlen + len - sizeof(struct ip);
15792 		udp->uh_ulen = htons(ulen);
15793 	}
15794 	m->m_pkthdr.rcvif = (struct ifnet *)0;
15795 	if (TCPS_HAVERCVDSYN(tp->t_state) &&
15796 	    (tp->t_flags2 & (TF2_ECN_PERMIT | TF2_ACE_PERMIT))) {
15797 		int ect = tcp_ecn_output_established(tp, &flags, len, true);
15798 		if ((tp->t_state == TCPS_SYN_RECEIVED) &&
15799 		    (tp->t_flags2 & TF2_ECN_SND_ECE))
15800 		    tp->t_flags2 &= ~TF2_ECN_SND_ECE;
15801 #ifdef INET6
15802 		if (rack->r_is_v6) {
15803 		    ip6->ip6_flow &= ~htonl(IPTOS_ECN_MASK << 20);
15804 		    ip6->ip6_flow |= htonl(ect << 20);
15805 		}
15806 		else
15807 #endif
15808 		{
15809 		    ip->ip_tos &= ~IPTOS_ECN_MASK;
15810 		    ip->ip_tos |= ect;
15811 		}
15812 	}
15813 	tcp_set_flags(th, flags);
15814 	m->m_pkthdr.len = hdrlen + len;	/* in6_cksum() need this */
15815 #ifdef INET6
15816 	if (rack->r_is_v6) {
15817 		if (tp->t_port) {
15818 			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
15819 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
15820 			udp->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0);
15821 			th->th_sum = htons(0);
15822 			UDPSTAT_INC(udps_opackets);
15823 		} else {
15824 			m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
15825 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
15826 			th->th_sum = in6_cksum_pseudo(ip6,
15827 						      sizeof(struct tcphdr) + optlen + len, IPPROTO_TCP,
15828 						      0);
15829 		}
15830 	}
15831 #endif
15832 #if defined(INET6) && defined(INET)
15833 	else
15834 #endif
15835 #ifdef INET
15836 	{
15837 		if (tp->t_port) {
15838 			m->m_pkthdr.csum_flags = CSUM_UDP;
15839 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
15840 			udp->uh_sum = in_pseudo(ip->ip_src.s_addr,
15841 						ip->ip_dst.s_addr, htons(ulen + IPPROTO_UDP));
15842 			th->th_sum = htons(0);
15843 			UDPSTAT_INC(udps_opackets);
15844 		} else {
15845 			m->m_pkthdr.csum_flags = CSUM_TCP;
15846 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
15847 			th->th_sum = in_pseudo(ip->ip_src.s_addr,
15848 					       ip->ip_dst.s_addr, htons(sizeof(struct tcphdr) +
15849 									IPPROTO_TCP + len + optlen));
15850 		}
15851 		/* IP version must be set here for ipv4/ipv6 checking later */
15852 		KASSERT(ip->ip_v == IPVERSION,
15853 			("%s: IP version incorrect: %d", __func__, ip->ip_v));
15854 	}
15855 #endif
15856 	if (tso) {
15857 		KASSERT(len > tp->t_maxseg - optlen,
15858 			("%s: len <= tso_segsz tp:%p", __func__, tp));
15859 		m->m_pkthdr.csum_flags |= CSUM_TSO;
15860 		m->m_pkthdr.tso_segsz = tp->t_maxseg - optlen;
15861 	}
15862 #ifdef INET6
15863 	if (rack->r_is_v6) {
15864 		ip6->ip6_hlim = rack->r_ctl.fsb.hoplimit;
15865 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
15866 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss)
15867 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
15868 		else
15869 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
15870 	}
15871 #endif
15872 #if defined(INET) && defined(INET6)
15873 	else
15874 #endif
15875 #ifdef INET
15876 	{
15877 		ip->ip_len = htons(m->m_pkthdr.len);
15878 		ip->ip_ttl = rack->r_ctl.fsb.hoplimit;
15879 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) {
15880 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
15881 			if (tp->t_port == 0 || len < V_tcp_minmss) {
15882 				ip->ip_off |= htons(IP_DF);
15883 			}
15884 		} else {
15885 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
15886 		}
15887 	}
15888 #endif
15889 	/* Time to copy in our header */
15890 	cpto = mtod(m, uint8_t *);
15891 	memcpy(cpto, rack->r_ctl.fsb.tcp_ip_hdr, rack->r_ctl.fsb.tcp_ip_hdr_len);
15892 	th = (struct tcphdr *)(cpto + ((uint8_t *)rack->r_ctl.fsb.th - rack->r_ctl.fsb.tcp_ip_hdr));
15893 	if (optlen) {
15894 		bcopy(opt, th + 1, optlen);
15895 		th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
15896 	} else {
15897 		th->th_off = sizeof(struct tcphdr) >> 2;
15898 	}
15899 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
15900 		union tcp_log_stackspecific log;
15901 
15902 		if (rsm->r_flags & RACK_RWND_COLLAPSED) {
15903 			rack_log_collapse(rack, rsm->r_start, rsm->r_end, 0, __LINE__, 5, rsm->r_flags, rsm);
15904 			counter_u64_add(rack_collapsed_win_rxt, 1);
15905 			counter_u64_add(rack_collapsed_win_rxt_bytes, (rsm->r_end - rsm->r_start));
15906 		}
15907 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
15908 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
15909 		if (rack->rack_no_prr)
15910 			log.u_bbr.flex1 = 0;
15911 		else
15912 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
15913 		log.u_bbr.flex2 = rack->r_ctl.rc_pace_min_segs;
15914 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_max_segs;
15915 		log.u_bbr.flex4 = max_val;
15916 		log.u_bbr.flex5 = 0;
15917 		/* Save off the early/late values */
15918 		log.u_bbr.flex6 = rack->r_ctl.rc_agg_early;
15919 		log.u_bbr.applimited = rack->r_ctl.rc_agg_delayed;
15920 		log.u_bbr.bw_inuse = rack_get_bw(rack);
15921 		if (doing_tlp == 0)
15922 			log.u_bbr.flex8 = 1;
15923 		else
15924 			log.u_bbr.flex8 = 2;
15925 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, NULL);
15926 		log.u_bbr.flex7 = 55;
15927 		log.u_bbr.pkts_out = tp->t_maxseg;
15928 		log.u_bbr.timeStamp = cts;
15929 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
15930 		log.u_bbr.lt_epoch = rack->r_ctl.cwnd_to_use;
15931 		log.u_bbr.delivered = 0;
15932 		lgb = tcp_log_event_(tp, th, NULL, NULL, TCP_LOG_OUT, ERRNO_UNK,
15933 				     len, &log, false, NULL, NULL, 0, tv);
15934 	} else
15935 		lgb = NULL;
15936 #ifdef INET6
15937 	if (rack->r_is_v6) {
15938 		error = ip6_output(m, NULL,
15939 				   &inp->inp_route6,
15940 				   0, NULL, NULL, inp);
15941 	}
15942 	else
15943 #endif
15944 #ifdef INET
15945 	{
15946 		error = ip_output(m, NULL,
15947 				  &inp->inp_route,
15948 				  0, 0, inp);
15949 	}
15950 #endif
15951 	m = NULL;
15952 	if (lgb) {
15953 		lgb->tlb_errno = error;
15954 		lgb = NULL;
15955 	}
15956 	if (error) {
15957 		goto failed;
15958 	}
15959 	rack_log_output(tp, &to, len, rsm->r_start, flags, error, rack_to_usec_ts(tv),
15960 			rsm, RACK_SENT_FP, rsm->m, rsm->soff, rsm->r_hw_tls);
15961 	if (doing_tlp && (rack->fast_rsm_hack == 0)) {
15962 		rack->rc_tlp_in_progress = 1;
15963 		rack->r_ctl.rc_tlp_cnt_out++;
15964 	}
15965 	if (error == 0) {
15966 		tcp_account_for_send(tp, len, 1, doing_tlp, rsm->r_hw_tls);
15967 		if (doing_tlp) {
15968 			rack->rc_last_sent_tlp_past_cumack = 0;
15969 			rack->rc_last_sent_tlp_seq_valid = 1;
15970 			rack->r_ctl.last_sent_tlp_seq = rsm->r_start;
15971 			rack->r_ctl.last_sent_tlp_len = rsm->r_end - rsm->r_start;
15972 		}
15973 	}
15974 	tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
15975 	rack->forced_ack = 0;	/* If we send something zap the FA flag */
15976 	if (IN_FASTRECOVERY(tp->t_flags) && rsm)
15977 		rack->r_ctl.retran_during_recovery += len;
15978 	{
15979 		int idx;
15980 
15981 		idx = (len / segsiz) + 3;
15982 		if (idx >= TCP_MSS_ACCT_ATIMER)
15983 			counter_u64_add(rack_out_size[(TCP_MSS_ACCT_ATIMER-1)], 1);
15984 		else
15985 			counter_u64_add(rack_out_size[idx], 1);
15986 	}
15987 	if (tp->t_rtttime == 0) {
15988 		tp->t_rtttime = ticks;
15989 		tp->t_rtseq = startseq;
15990 		KMOD_TCPSTAT_INC(tcps_segstimed);
15991 	}
15992 	counter_u64_add(rack_fto_rsm_send, 1);
15993 	if (error && (error == ENOBUFS)) {
15994 		if (rack->r_ctl.crte != NULL) {
15995 			rack_trace_point(rack, RACK_TP_HWENOBUF);
15996 		} else
15997 			rack_trace_point(rack, RACK_TP_ENOBUF);
15998 		slot = ((1 + rack->rc_enobuf) * HPTS_USEC_IN_MSEC);
15999 		if (rack->rc_enobuf < 0x7f)
16000 			rack->rc_enobuf++;
16001 		if (slot < (10 * HPTS_USEC_IN_MSEC))
16002 			slot = 10 * HPTS_USEC_IN_MSEC;
16003 	} else
16004 		slot = rack_get_pacing_delay(rack, tp, len, NULL, segsiz);
16005 	if ((slot == 0) ||
16006 	    (rack->rc_always_pace == 0) ||
16007 	    (rack->r_rr_config == 1)) {
16008 		/*
16009 		 * We have no pacing set or we
16010 		 * are using old-style rack or
16011 		 * we are overridden to use the old 1ms pacing.
16012 		 */
16013 		slot = rack->r_ctl.rc_min_to;
16014 	}
16015 	rack_start_hpts_timer(rack, tp, cts, slot, len, 0);
16016 #ifdef TCP_ACCOUNTING
16017 	crtsc = get_cyclecount();
16018 	if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16019 		tp->tcp_cnt_counters[SND_OUT_DATA] += cnt_thru;
16020 	}
16021 	counter_u64_add(tcp_cnt_counters[SND_OUT_DATA], cnt_thru);
16022 	if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16023 		tp->tcp_proc_time[SND_OUT_DATA] += (crtsc - ts_val);
16024 	}
16025 	counter_u64_add(tcp_proc_time[SND_OUT_DATA], (crtsc - ts_val));
16026 	if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16027 		tp->tcp_cnt_counters[CNT_OF_MSS_OUT] += ((len + segsiz - 1) / segsiz);
16028 	}
16029 	counter_u64_add(tcp_cnt_counters[CNT_OF_MSS_OUT], ((len + segsiz - 1) / segsiz));
16030 	sched_unpin();
16031 #endif
16032 	return (0);
16033 failed:
16034 	if (m)
16035 		m_free(m);
16036 	return (-1);
16037 }
16038 
16039 static void
16040 rack_sndbuf_autoscale(struct tcp_rack *rack)
16041 {
16042 	/*
16043 	 * Automatic sizing of send socket buffer.  Often the send buffer
16044 	 * size is not optimally adjusted to the actual network conditions
16045 	 * at hand (delay bandwidth product).  Setting the buffer size too
16046 	 * small limits throughput on links with high bandwidth and high
16047 	 * delay (eg. trans-continental/oceanic links).  Setting the
16048 	 * buffer size too big consumes too much real kernel memory,
16049 	 * especially with many connections on busy servers.
16050 	 *
16051 	 * The criteria to step up the send buffer one notch are:
16052 	 *  1. receive window of remote host is larger than send buffer
16053 	 *     (with a fudge factor of 5/4th);
16054 	 *  2. send buffer is filled to 7/8th with data (so we actually
16055 	 *     have data to make use of it);
16056 	 *  3. send buffer fill has not hit maximal automatic size;
16057 	 *  4. our send window (slow start and cogestion controlled) is
16058 	 *     larger than sent but unacknowledged data in send buffer.
16059 	 *
16060 	 * Note that the rack version moves things much faster since
16061 	 * we want to avoid hitting cache lines in the rack_fast_output()
16062 	 * path so this is called much less often and thus moves
16063 	 * the SB forward by a percentage.
16064 	 */
16065 	struct socket *so;
16066 	struct tcpcb *tp;
16067 	uint32_t sendwin, scaleup;
16068 
16069 	tp = rack->rc_tp;
16070 	so = rack->rc_inp->inp_socket;
16071 	sendwin = min(rack->r_ctl.cwnd_to_use, tp->snd_wnd);
16072 	if (V_tcp_do_autosndbuf && so->so_snd.sb_flags & SB_AUTOSIZE) {
16073 		if ((tp->snd_wnd / 4 * 5) >= so->so_snd.sb_hiwat &&
16074 		    sbused(&so->so_snd) >=
16075 		    (so->so_snd.sb_hiwat / 8 * 7) &&
16076 		    sbused(&so->so_snd) < V_tcp_autosndbuf_max &&
16077 		    sendwin >= (sbused(&so->so_snd) -
16078 		    (tp->snd_nxt - tp->snd_una))) {
16079 			if (rack_autosndbuf_inc)
16080 				scaleup = (rack_autosndbuf_inc * so->so_snd.sb_hiwat) / 100;
16081 			else
16082 				scaleup = V_tcp_autosndbuf_inc;
16083 			if (scaleup < V_tcp_autosndbuf_inc)
16084 				scaleup = V_tcp_autosndbuf_inc;
16085 			scaleup += so->so_snd.sb_hiwat;
16086 			if (scaleup > V_tcp_autosndbuf_max)
16087 				scaleup = V_tcp_autosndbuf_max;
16088 			if (!sbreserve_locked(so, SO_SND, scaleup, curthread))
16089 				so->so_snd.sb_flags &= ~SB_AUTOSIZE;
16090 		}
16091 	}
16092 }
16093 
16094 static int
16095 rack_fast_output(struct tcpcb *tp, struct tcp_rack *rack, uint64_t ts_val,
16096 		 uint32_t cts, uint32_t ms_cts, struct timeval *tv, long tot_len, int *send_err)
16097 {
16098 	/*
16099 	 * Enter to do fast output. We are given that the sched_pin is
16100 	 * in place (if accounting is compiled in) and the cycle count taken
16101 	 * at entry is in place in ts_val. The idea here is that
16102 	 * we know how many more bytes needs to be sent (presumably either
16103 	 * during pacing or to fill the cwnd and that was greater than
16104 	 * the max-burst). We have how much to send and all the info we
16105 	 * need to just send.
16106 	 */
16107 #ifdef INET
16108 	struct ip *ip = NULL;
16109 #endif
16110 	struct udphdr *udp = NULL;
16111 	struct tcphdr *th = NULL;
16112 	struct mbuf *m, *s_mb;
16113 	struct inpcb *inp;
16114 	uint8_t *cpto;
16115 	struct tcp_log_buffer *lgb;
16116 #ifdef TCP_ACCOUNTING
16117 	uint64_t crtsc;
16118 #endif
16119 	struct tcpopt to;
16120 	u_char opt[TCP_MAXOLEN];
16121 	uint32_t hdrlen, optlen;
16122 #ifdef TCP_ACCOUNTING
16123 	int cnt_thru = 1;
16124 #endif
16125 	int32_t slot, segsiz, len, max_val, tso = 0, sb_offset, error, ulen = 0;
16126 	uint16_t flags;
16127 	uint32_t s_soff;
16128 	uint32_t if_hw_tsomaxsegcount = 0, startseq;
16129 	uint32_t if_hw_tsomaxsegsize;
16130 	uint16_t add_flag = RACK_SENT_FP;
16131 #ifdef INET6
16132 	struct ip6_hdr *ip6 = NULL;
16133 
16134 	if (rack->r_is_v6) {
16135 		ip6 = (struct ip6_hdr *)rack->r_ctl.fsb.tcp_ip_hdr;
16136 		hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
16137 	} else
16138 #endif				/* INET6 */
16139 	{
16140 #ifdef INET
16141 		ip = (struct ip *)rack->r_ctl.fsb.tcp_ip_hdr;
16142 		hdrlen = sizeof(struct tcpiphdr);
16143 #endif
16144 	}
16145 	if (tp->t_port && (V_tcp_udp_tunneling_port == 0)) {
16146 		m = NULL;
16147 		goto failed;
16148 	}
16149 	startseq = tp->snd_max;
16150 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
16151 	inp = rack->rc_inp;
16152 	len = rack->r_ctl.fsb.left_to_send;
16153 	to.to_flags = 0;
16154 	flags = rack->r_ctl.fsb.tcp_flags;
16155 	if (tp->t_flags & TF_RCVD_TSTMP) {
16156 		to.to_tsval = ms_cts + tp->ts_offset;
16157 		to.to_tsecr = tp->ts_recent;
16158 		to.to_flags = TOF_TS;
16159 	}
16160 	optlen = tcp_addoptions(&to, opt);
16161 	hdrlen += optlen;
16162 	udp = rack->r_ctl.fsb.udp;
16163 	if (udp)
16164 		hdrlen += sizeof(struct udphdr);
16165 	if (rack->r_ctl.rc_pace_max_segs)
16166 		max_val = rack->r_ctl.rc_pace_max_segs;
16167 	else if (rack->rc_user_set_max_segs)
16168 		max_val = rack->rc_user_set_max_segs * segsiz;
16169 	else
16170 		max_val = len;
16171 	if ((tp->t_flags & TF_TSO) &&
16172 	    V_tcp_do_tso &&
16173 	    (len > segsiz) &&
16174 	    (tp->t_port == 0))
16175 		tso = 1;
16176 again:
16177 #ifdef INET6
16178 	if (MHLEN < hdrlen + max_linkhdr)
16179 		m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
16180 	else
16181 #endif
16182 		m = m_gethdr(M_NOWAIT, MT_DATA);
16183 	if (m == NULL)
16184 		goto failed;
16185 	m->m_data += max_linkhdr;
16186 	m->m_len = hdrlen;
16187 	th = rack->r_ctl.fsb.th;
16188 	/* Establish the len to send */
16189 	if (len > max_val)
16190 		len = max_val;
16191 	if ((tso) && (len + optlen > tp->t_maxseg)) {
16192 		uint32_t if_hw_tsomax;
16193 		int32_t max_len;
16194 
16195 		/* extract TSO information */
16196 		if_hw_tsomax = tp->t_tsomax;
16197 		if_hw_tsomaxsegcount = tp->t_tsomaxsegcount;
16198 		if_hw_tsomaxsegsize = tp->t_tsomaxsegsize;
16199 		/*
16200 		 * Check if we should limit by maximum payload
16201 		 * length:
16202 		 */
16203 		if (if_hw_tsomax != 0) {
16204 			/* compute maximum TSO length */
16205 			max_len = (if_hw_tsomax - hdrlen -
16206 				   max_linkhdr);
16207 			if (max_len <= 0) {
16208 				goto failed;
16209 			} else if (len > max_len) {
16210 				len = max_len;
16211 			}
16212 		}
16213 		if (len <= segsiz) {
16214 			/*
16215 			 * In case there are too many small fragments don't
16216 			 * use TSO:
16217 			 */
16218 			tso = 0;
16219 		}
16220 	} else {
16221 		tso = 0;
16222 	}
16223 	if ((tso == 0) && (len > segsiz))
16224 		len = segsiz;
16225 	if ((len == 0) ||
16226 	    (len <= MHLEN - hdrlen - max_linkhdr)) {
16227 		goto failed;
16228 	}
16229 	sb_offset = tp->snd_max - tp->snd_una;
16230 	th->th_seq = htonl(tp->snd_max);
16231 	th->th_ack = htonl(tp->rcv_nxt);
16232 	th->th_win = htons((u_short)(rack->r_ctl.fsb.recwin >> tp->rcv_scale));
16233 	if (th->th_win == 0) {
16234 		tp->t_sndzerowin++;
16235 		tp->t_flags |= TF_RXWIN0SENT;
16236 	} else
16237 		tp->t_flags &= ~TF_RXWIN0SENT;
16238 	tp->snd_up = tp->snd_una;	/* drag it along, its deprecated */
16239 	KMOD_TCPSTAT_INC(tcps_sndpack);
16240 	KMOD_TCPSTAT_ADD(tcps_sndbyte, len);
16241 #ifdef STATS
16242 	stats_voi_update_abs_u64(tp->t_stats, VOI_TCP_TXPB,
16243 				 len);
16244 #endif
16245 	if (rack->r_ctl.fsb.m == NULL)
16246 		goto failed;
16247 
16248 	/* s_mb and s_soff are saved for rack_log_output */
16249 	m->m_next = rack_fo_m_copym(rack, &len, if_hw_tsomaxsegcount, if_hw_tsomaxsegsize,
16250 				    &s_mb, &s_soff);
16251 	if (len <= segsiz) {
16252 		/*
16253 		 * Must have ran out of mbufs for the copy
16254 		 * shorten it to no longer need tso. Lets
16255 		 * not put on sendalot since we are low on
16256 		 * mbufs.
16257 		 */
16258 		tso = 0;
16259 	}
16260 	if (rack->r_ctl.fsb.rfo_apply_push &&
16261 	    (len == rack->r_ctl.fsb.left_to_send)) {
16262 		flags |= TH_PUSH;
16263 		add_flag |= RACK_HAD_PUSH;
16264 	}
16265 	if ((m->m_next == NULL) || (len <= 0)){
16266 		goto failed;
16267 	}
16268 	if (udp) {
16269 		if (rack->r_is_v6)
16270 			ulen = hdrlen + len - sizeof(struct ip6_hdr);
16271 		else
16272 			ulen = hdrlen + len - sizeof(struct ip);
16273 		udp->uh_ulen = htons(ulen);
16274 	}
16275 	m->m_pkthdr.rcvif = (struct ifnet *)0;
16276 	if (TCPS_HAVERCVDSYN(tp->t_state) &&
16277 	    (tp->t_flags2 & (TF2_ECN_PERMIT | TF2_ACE_PERMIT))) {
16278 		int ect = tcp_ecn_output_established(tp, &flags, len, false);
16279 		if ((tp->t_state == TCPS_SYN_RECEIVED) &&
16280 		    (tp->t_flags2 & TF2_ECN_SND_ECE))
16281 			tp->t_flags2 &= ~TF2_ECN_SND_ECE;
16282 #ifdef INET6
16283 		if (rack->r_is_v6) {
16284 			ip6->ip6_flow &= ~htonl(IPTOS_ECN_MASK << 20);
16285 			ip6->ip6_flow |= htonl(ect << 20);
16286 		}
16287 		else
16288 #endif
16289 		{
16290 #ifdef INET
16291 			ip->ip_tos &= ~IPTOS_ECN_MASK;
16292 			ip->ip_tos |= ect;
16293 #endif
16294 		}
16295 	}
16296 	tcp_set_flags(th, flags);
16297 	m->m_pkthdr.len = hdrlen + len;	/* in6_cksum() need this */
16298 #ifdef INET6
16299 	if (rack->r_is_v6) {
16300 		if (tp->t_port) {
16301 			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
16302 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
16303 			udp->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0);
16304 			th->th_sum = htons(0);
16305 			UDPSTAT_INC(udps_opackets);
16306 		} else {
16307 			m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
16308 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
16309 			th->th_sum = in6_cksum_pseudo(ip6,
16310 						      sizeof(struct tcphdr) + optlen + len, IPPROTO_TCP,
16311 						      0);
16312 		}
16313 	}
16314 #endif
16315 #if defined(INET6) && defined(INET)
16316 	else
16317 #endif
16318 #ifdef INET
16319 	{
16320 		if (tp->t_port) {
16321 			m->m_pkthdr.csum_flags = CSUM_UDP;
16322 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
16323 			udp->uh_sum = in_pseudo(ip->ip_src.s_addr,
16324 						ip->ip_dst.s_addr, htons(ulen + IPPROTO_UDP));
16325 			th->th_sum = htons(0);
16326 			UDPSTAT_INC(udps_opackets);
16327 		} else {
16328 			m->m_pkthdr.csum_flags = CSUM_TCP;
16329 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
16330 			th->th_sum = in_pseudo(ip->ip_src.s_addr,
16331 					       ip->ip_dst.s_addr, htons(sizeof(struct tcphdr) +
16332 									IPPROTO_TCP + len + optlen));
16333 		}
16334 		/* IP version must be set here for ipv4/ipv6 checking later */
16335 		KASSERT(ip->ip_v == IPVERSION,
16336 			("%s: IP version incorrect: %d", __func__, ip->ip_v));
16337 	}
16338 #endif
16339 	if (tso) {
16340 		KASSERT(len > tp->t_maxseg - optlen,
16341 			("%s: len <= tso_segsz tp:%p", __func__, tp));
16342 		m->m_pkthdr.csum_flags |= CSUM_TSO;
16343 		m->m_pkthdr.tso_segsz = tp->t_maxseg - optlen;
16344 	}
16345 #ifdef INET6
16346 	if (rack->r_is_v6) {
16347 		ip6->ip6_hlim = rack->r_ctl.fsb.hoplimit;
16348 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
16349 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss)
16350 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
16351 		else
16352 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
16353 	}
16354 #endif
16355 #if defined(INET) && defined(INET6)
16356 	else
16357 #endif
16358 #ifdef INET
16359 	{
16360 		ip->ip_len = htons(m->m_pkthdr.len);
16361 		ip->ip_ttl = rack->r_ctl.fsb.hoplimit;
16362 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) {
16363 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
16364 			if (tp->t_port == 0 || len < V_tcp_minmss) {
16365 				ip->ip_off |= htons(IP_DF);
16366 			}
16367 		} else {
16368 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
16369 		}
16370 	}
16371 #endif
16372 	/* Time to copy in our header */
16373 	cpto = mtod(m, uint8_t *);
16374 	memcpy(cpto, rack->r_ctl.fsb.tcp_ip_hdr, rack->r_ctl.fsb.tcp_ip_hdr_len);
16375 	th = (struct tcphdr *)(cpto + ((uint8_t *)rack->r_ctl.fsb.th - rack->r_ctl.fsb.tcp_ip_hdr));
16376 	if (optlen) {
16377 		bcopy(opt, th + 1, optlen);
16378 		th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
16379 	} else {
16380 		th->th_off = sizeof(struct tcphdr) >> 2;
16381 	}
16382 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
16383 		union tcp_log_stackspecific log;
16384 
16385 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
16386 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
16387 		if (rack->rack_no_prr)
16388 			log.u_bbr.flex1 = 0;
16389 		else
16390 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
16391 		log.u_bbr.flex2 = rack->r_ctl.rc_pace_min_segs;
16392 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_max_segs;
16393 		log.u_bbr.flex4 = max_val;
16394 		log.u_bbr.flex5 = 0;
16395 		/* Save off the early/late values */
16396 		log.u_bbr.flex6 = rack->r_ctl.rc_agg_early;
16397 		log.u_bbr.applimited = rack->r_ctl.rc_agg_delayed;
16398 		log.u_bbr.bw_inuse = rack_get_bw(rack);
16399 		log.u_bbr.flex8 = 0;
16400 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, NULL);
16401 		log.u_bbr.flex7 = 44;
16402 		log.u_bbr.pkts_out = tp->t_maxseg;
16403 		log.u_bbr.timeStamp = cts;
16404 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
16405 		log.u_bbr.lt_epoch = rack->r_ctl.cwnd_to_use;
16406 		log.u_bbr.delivered = 0;
16407 		lgb = tcp_log_event_(tp, th, NULL, NULL, TCP_LOG_OUT, ERRNO_UNK,
16408 				     len, &log, false, NULL, NULL, 0, tv);
16409 	} else
16410 		lgb = NULL;
16411 #ifdef INET6
16412 	if (rack->r_is_v6) {
16413 		error = ip6_output(m, NULL,
16414 				   &inp->inp_route6,
16415 				   0, NULL, NULL, inp);
16416 	}
16417 #endif
16418 #if defined(INET) && defined(INET6)
16419 	else
16420 #endif
16421 #ifdef INET
16422 	{
16423 		error = ip_output(m, NULL,
16424 				  &inp->inp_route,
16425 				  0, 0, inp);
16426 	}
16427 #endif
16428 	if (lgb) {
16429 		lgb->tlb_errno = error;
16430 		lgb = NULL;
16431 	}
16432 	if (error) {
16433 		*send_err = error;
16434 		m = NULL;
16435 		goto failed;
16436 	}
16437 	rack_log_output(tp, &to, len, tp->snd_max, flags, error, rack_to_usec_ts(tv),
16438 			NULL, add_flag, s_mb, s_soff, rack->r_ctl.fsb.hw_tls);
16439 	m = NULL;
16440 	if (tp->snd_una == tp->snd_max) {
16441 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
16442 		rack_log_progress_event(rack, tp, ticks, PROGRESS_START, __LINE__);
16443 		tp->t_acktime = ticks;
16444 	}
16445 	if (error == 0)
16446 		tcp_account_for_send(tp, len, 0, 0, rack->r_ctl.fsb.hw_tls);
16447 
16448 	rack->forced_ack = 0;	/* If we send something zap the FA flag */
16449 	tot_len += len;
16450 	if ((tp->t_flags & TF_GPUTINPROG) == 0)
16451 		rack_start_gp_measurement(tp, rack, tp->snd_max, sb_offset);
16452 	tp->snd_max += len;
16453 	tp->snd_nxt = tp->snd_max;
16454 	{
16455 		int idx;
16456 
16457 		idx = (len / segsiz) + 3;
16458 		if (idx >= TCP_MSS_ACCT_ATIMER)
16459 			counter_u64_add(rack_out_size[(TCP_MSS_ACCT_ATIMER-1)], 1);
16460 		else
16461 			counter_u64_add(rack_out_size[idx], 1);
16462 	}
16463 	if (len <= rack->r_ctl.fsb.left_to_send)
16464 		rack->r_ctl.fsb.left_to_send -= len;
16465 	else
16466 		rack->r_ctl.fsb.left_to_send = 0;
16467 	if (rack->r_ctl.fsb.left_to_send < segsiz) {
16468 		rack->r_fast_output = 0;
16469 		rack->r_ctl.fsb.left_to_send = 0;
16470 		/* At the end of fast_output scale up the sb */
16471 		SOCKBUF_LOCK(&rack->rc_inp->inp_socket->so_snd);
16472 		rack_sndbuf_autoscale(rack);
16473 		SOCKBUF_UNLOCK(&rack->rc_inp->inp_socket->so_snd);
16474 	}
16475 	if (tp->t_rtttime == 0) {
16476 		tp->t_rtttime = ticks;
16477 		tp->t_rtseq = startseq;
16478 		KMOD_TCPSTAT_INC(tcps_segstimed);
16479 	}
16480 	if ((rack->r_ctl.fsb.left_to_send >= segsiz) &&
16481 	    (max_val > len) &&
16482 	    (tso == 0)) {
16483 		max_val -= len;
16484 		len = segsiz;
16485 		th = rack->r_ctl.fsb.th;
16486 #ifdef TCP_ACCOUNTING
16487 		cnt_thru++;
16488 #endif
16489 		goto again;
16490 	}
16491 	tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
16492 	counter_u64_add(rack_fto_send, 1);
16493 	slot = rack_get_pacing_delay(rack, tp, tot_len, NULL, segsiz);
16494 	rack_start_hpts_timer(rack, tp, cts, slot, tot_len, 0);
16495 #ifdef TCP_ACCOUNTING
16496 	crtsc = get_cyclecount();
16497 	if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16498 		tp->tcp_cnt_counters[SND_OUT_DATA] += cnt_thru;
16499 	}
16500 	counter_u64_add(tcp_cnt_counters[SND_OUT_DATA], cnt_thru);
16501 	if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16502 		tp->tcp_proc_time[SND_OUT_DATA] += (crtsc - ts_val);
16503 	}
16504 	counter_u64_add(tcp_proc_time[SND_OUT_DATA], (crtsc - ts_val));
16505 	if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16506 		tp->tcp_cnt_counters[CNT_OF_MSS_OUT] += ((tot_len + segsiz - 1) / segsiz);
16507 	}
16508 	counter_u64_add(tcp_cnt_counters[CNT_OF_MSS_OUT], ((tot_len + segsiz - 1) / segsiz));
16509 	sched_unpin();
16510 #endif
16511 	return (0);
16512 failed:
16513 	if (m)
16514 		m_free(m);
16515 	rack->r_fast_output = 0;
16516 	return (-1);
16517 }
16518 
16519 static struct rack_sendmap *
16520 rack_check_collapsed(struct tcp_rack *rack, uint32_t cts)
16521 {
16522 	struct rack_sendmap *rsm = NULL;
16523 	struct rack_sendmap fe;
16524 	int thresh;
16525 
16526 restart:
16527 	fe.r_start = rack->r_ctl.last_collapse_point;
16528 	rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
16529 	if ((rsm == NULL) || ((rsm->r_flags & RACK_RWND_COLLAPSED) == 0)) {
16530 		/* Nothing, strange turn off validity  */
16531 		rack->r_collapse_point_valid = 0;
16532 		return (NULL);
16533 	}
16534 	/* Can we send it yet? */
16535 	if (rsm->r_end > (rack->rc_tp->snd_una + rack->rc_tp->snd_wnd)) {
16536 		/*
16537 		 * Receiver window has not grown enough for
16538 		 * the segment to be put on the wire.
16539 		 */
16540 		return (NULL);
16541 	}
16542 	if (rsm->r_flags & RACK_ACKED) {
16543 		/*
16544 		 * It has been sacked, lets move to the
16545 		 * next one if possible.
16546 		 */
16547 		rack->r_ctl.last_collapse_point = rsm->r_end;
16548 		/* Are we done? */
16549 		if (SEQ_GEQ(rack->r_ctl.last_collapse_point,
16550 			    rack->r_ctl.high_collapse_point)) {
16551 			rack->r_collapse_point_valid = 0;
16552 			return (NULL);
16553 		}
16554 		goto restart;
16555 	}
16556 	/* Now has it been long enough ? */
16557 	thresh = rack_calc_thresh_rack(rack, rack_grab_rtt(rack->rc_tp, rack), cts);
16558 	if ((cts - ((uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)])) > thresh) {
16559 		rack_log_collapse(rack, rsm->r_start,
16560 				  (cts - ((uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)])),
16561 				  thresh, __LINE__, 6, rsm->r_flags, rsm);
16562 		return (rsm);
16563 	}
16564 	/* Not enough time */
16565 	rack_log_collapse(rack, rsm->r_start,
16566 			  (cts - ((uint32_t)rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)])),
16567 			  thresh, __LINE__, 7, rsm->r_flags, rsm);
16568 	return (NULL);
16569 }
16570 
16571 static int
16572 rack_output(struct tcpcb *tp)
16573 {
16574 	struct socket *so;
16575 	uint32_t recwin;
16576 	uint32_t sb_offset, s_moff = 0;
16577 	int32_t len, error = 0;
16578 	uint16_t flags;
16579 	struct mbuf *m, *s_mb = NULL;
16580 	struct mbuf *mb;
16581 	uint32_t if_hw_tsomaxsegcount = 0;
16582 	uint32_t if_hw_tsomaxsegsize;
16583 	int32_t segsiz, minseg;
16584 	long tot_len_this_send = 0;
16585 #ifdef INET
16586 	struct ip *ip = NULL;
16587 #endif
16588 	struct udphdr *udp = NULL;
16589 	struct tcp_rack *rack;
16590 	struct tcphdr *th;
16591 	uint8_t pass = 0;
16592 	uint8_t mark = 0;
16593 	uint8_t wanted_cookie = 0;
16594 	u_char opt[TCP_MAXOLEN];
16595 	unsigned ipoptlen, optlen, hdrlen, ulen=0;
16596 	uint32_t rack_seq;
16597 
16598 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
16599 	unsigned ipsec_optlen = 0;
16600 
16601 #endif
16602 	int32_t idle, sendalot;
16603 	int32_t sub_from_prr = 0;
16604 	volatile int32_t sack_rxmit;
16605 	struct rack_sendmap *rsm = NULL;
16606 	int32_t tso, mtu;
16607 	struct tcpopt to;
16608 	int32_t slot = 0;
16609 	int32_t sup_rack = 0;
16610 	uint32_t cts, ms_cts, delayed, early;
16611 	uint16_t add_flag = RACK_SENT_SP;
16612 	/* The doing_tlp flag will be set by the actual rack_timeout_tlp() */
16613 	uint8_t hpts_calling,  doing_tlp = 0;
16614 	uint32_t cwnd_to_use, pace_max_seg;
16615 	int32_t do_a_prefetch = 0;
16616 	int32_t prefetch_rsm = 0;
16617 	int32_t orig_len = 0;
16618 	struct timeval tv;
16619 	int32_t prefetch_so_done = 0;
16620 	struct tcp_log_buffer *lgb;
16621 	struct inpcb *inp = tptoinpcb(tp);
16622 	struct sockbuf *sb;
16623 	uint64_t ts_val = 0;
16624 #ifdef TCP_ACCOUNTING
16625 	uint64_t crtsc;
16626 #endif
16627 #ifdef INET6
16628 	struct ip6_hdr *ip6 = NULL;
16629 	int32_t isipv6;
16630 #endif
16631 	bool hw_tls = false;
16632 
16633 	NET_EPOCH_ASSERT();
16634 	INP_WLOCK_ASSERT(inp);
16635 
16636 	/* setup and take the cache hits here */
16637 	rack = (struct tcp_rack *)tp->t_fb_ptr;
16638 #ifdef TCP_ACCOUNTING
16639 	sched_pin();
16640 	ts_val = get_cyclecount();
16641 #endif
16642 	hpts_calling = inp->inp_hpts_calls;
16643 #ifdef TCP_OFFLOAD
16644 	if (tp->t_flags & TF_TOE) {
16645 #ifdef TCP_ACCOUNTING
16646 		sched_unpin();
16647 #endif
16648 		return (tcp_offload_output(tp));
16649 	}
16650 #endif
16651 	/*
16652 	 * For TFO connections in SYN_RECEIVED, only allow the initial
16653 	 * SYN|ACK and those sent by the retransmit timer.
16654 	 */
16655 	if (IS_FASTOPEN(tp->t_flags) &&
16656 	    (tp->t_state == TCPS_SYN_RECEIVED) &&
16657 	    SEQ_GT(tp->snd_max, tp->snd_una) &&    /* initial SYN|ACK sent */
16658 	    (rack->r_ctl.rc_resend == NULL)) {         /* not a retransmit */
16659 #ifdef TCP_ACCOUNTING
16660 		sched_unpin();
16661 #endif
16662 		return (0);
16663 	}
16664 #ifdef INET6
16665 	if (rack->r_state) {
16666 		/* Use the cache line loaded if possible */
16667 		isipv6 = rack->r_is_v6;
16668 	} else {
16669 		isipv6 = (rack->rc_inp->inp_vflag & INP_IPV6) != 0;
16670 	}
16671 #endif
16672 	early = 0;
16673 	cts = tcp_get_usecs(&tv);
16674 	ms_cts = tcp_tv_to_mssectick(&tv);
16675 	if (((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0) &&
16676 	    tcp_in_hpts(rack->rc_inp)) {
16677 		/*
16678 		 * We are on the hpts for some timer but not hptsi output.
16679 		 * Remove from the hpts unconditionally.
16680 		 */
16681 		rack_timer_cancel(tp, rack, cts, __LINE__);
16682 	}
16683 	/* Are we pacing and late? */
16684 	if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
16685 	    TSTMP_GEQ(cts, rack->r_ctl.rc_last_output_to)) {
16686 		/* We are delayed */
16687 		delayed = cts - rack->r_ctl.rc_last_output_to;
16688 	} else {
16689 		delayed = 0;
16690 	}
16691 	/* Do the timers, which may override the pacer */
16692 	if (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) {
16693 		int retval;
16694 
16695 		retval = rack_process_timers(tp, rack, cts, hpts_calling,
16696 		    &doing_tlp);
16697 		if (retval != 0) {
16698 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_ATIMER], 1);
16699 #ifdef TCP_ACCOUNTING
16700 			sched_unpin();
16701 #endif
16702 			/*
16703 			 * If timers want tcp_drop(), then pass error out,
16704 			 * otherwise suppress it.
16705 			 */
16706 			return (retval < 0 ? retval : 0);
16707 		}
16708 	}
16709 	if (rack->rc_in_persist) {
16710 		if (tcp_in_hpts(rack->rc_inp) == 0) {
16711 			/* Timer is not running */
16712 			rack_start_hpts_timer(rack, tp, cts, 0, 0, 0);
16713 		}
16714 #ifdef TCP_ACCOUNTING
16715 		sched_unpin();
16716 #endif
16717 		return (0);
16718 	}
16719 	if ((rack->rc_ack_required == 1) &&
16720 	    (rack->r_timer_override == 0)){
16721 		/* A timeout occurred and no ack has arrived */
16722 		if (tcp_in_hpts(rack->rc_inp) == 0) {
16723 			/* Timer is not running */
16724 			rack_start_hpts_timer(rack, tp, cts, 0, 0, 0);
16725 		}
16726 #ifdef TCP_ACCOUNTING
16727 		sched_unpin();
16728 #endif
16729 		return (0);
16730 	}
16731 	if ((rack->r_timer_override) ||
16732 	    (rack->rc_ack_can_sendout_data) ||
16733 	    (delayed) ||
16734 	    (tp->t_state < TCPS_ESTABLISHED)) {
16735 		rack->rc_ack_can_sendout_data = 0;
16736 		if (tcp_in_hpts(rack->rc_inp))
16737 			tcp_hpts_remove(rack->rc_inp);
16738 	} else if (tcp_in_hpts(rack->rc_inp)) {
16739 		/*
16740 		 * On the hpts you can't pass even if ACKNOW is on, we will
16741 		 * when the hpts fires.
16742 		 */
16743 #ifdef TCP_ACCOUNTING
16744 		crtsc = get_cyclecount();
16745 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16746 			tp->tcp_proc_time[SND_BLOCKED] += (crtsc - ts_val);
16747 		}
16748 		counter_u64_add(tcp_proc_time[SND_BLOCKED], (crtsc - ts_val));
16749 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
16750 			tp->tcp_cnt_counters[SND_BLOCKED]++;
16751 		}
16752 		counter_u64_add(tcp_cnt_counters[SND_BLOCKED], 1);
16753 		sched_unpin();
16754 #endif
16755 		counter_u64_add(rack_out_size[TCP_MSS_ACCT_INPACE], 1);
16756 		return (0);
16757 	}
16758 	rack->rc_inp->inp_hpts_calls = 0;
16759 	/* Finish out both pacing early and late accounting */
16760 	if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
16761 	    TSTMP_GT(rack->r_ctl.rc_last_output_to, cts)) {
16762 		early = rack->r_ctl.rc_last_output_to - cts;
16763 	} else
16764 		early = 0;
16765 	if (delayed) {
16766 		rack->r_ctl.rc_agg_delayed += delayed;
16767 		rack->r_late = 1;
16768 	} else if (early) {
16769 		rack->r_ctl.rc_agg_early += early;
16770 		rack->r_early = 1;
16771 	}
16772 	/* Now that early/late accounting is done turn off the flag */
16773 	rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
16774 	rack->r_wanted_output = 0;
16775 	rack->r_timer_override = 0;
16776 	if ((tp->t_state != rack->r_state) &&
16777 	    TCPS_HAVEESTABLISHED(tp->t_state)) {
16778 		rack_set_state(tp, rack);
16779 	}
16780 	if ((rack->r_fast_output) &&
16781 	    (doing_tlp == 0) &&
16782 	    (tp->rcv_numsacks == 0)) {
16783 		int ret;
16784 
16785 		error = 0;
16786 		ret = rack_fast_output(tp, rack, ts_val, cts, ms_cts, &tv, tot_len_this_send, &error);
16787 		if (ret >= 0)
16788 			return(ret);
16789 		else if (error) {
16790 			inp = rack->rc_inp;
16791 			so = inp->inp_socket;
16792 			sb = &so->so_snd;
16793 			goto nomore;
16794 		}
16795 	}
16796 	inp = rack->rc_inp;
16797 	/*
16798 	 * For TFO connections in SYN_SENT or SYN_RECEIVED,
16799 	 * only allow the initial SYN or SYN|ACK and those sent
16800 	 * by the retransmit timer.
16801 	 */
16802 	if (IS_FASTOPEN(tp->t_flags) &&
16803 	    ((tp->t_state == TCPS_SYN_RECEIVED) ||
16804 	     (tp->t_state == TCPS_SYN_SENT)) &&
16805 	    SEQ_GT(tp->snd_max, tp->snd_una) && /* initial SYN or SYN|ACK sent */
16806 	    (tp->t_rxtshift == 0)) {              /* not a retransmit */
16807 		cwnd_to_use = rack->r_ctl.cwnd_to_use = tp->snd_cwnd;
16808 		so = inp->inp_socket;
16809 		sb = &so->so_snd;
16810 		goto just_return_nolock;
16811 	}
16812 	/*
16813 	 * Determine length of data that should be transmitted, and flags
16814 	 * that will be used. If there is some data or critical controls
16815 	 * (SYN, RST) to send, then transmit; otherwise, investigate
16816 	 * further.
16817 	 */
16818 	idle = (tp->t_flags & TF_LASTIDLE) || (tp->snd_max == tp->snd_una);
16819 	if (tp->t_idle_reduce) {
16820 		if (idle && (TICKS_2_USEC(ticks - tp->t_rcvtime) >= tp->t_rxtcur))
16821 			rack_cc_after_idle(rack, tp);
16822 	}
16823 	tp->t_flags &= ~TF_LASTIDLE;
16824 	if (idle) {
16825 		if (tp->t_flags & TF_MORETOCOME) {
16826 			tp->t_flags |= TF_LASTIDLE;
16827 			idle = 0;
16828 		}
16829 	}
16830 	if ((tp->snd_una == tp->snd_max) &&
16831 	    rack->r_ctl.rc_went_idle_time &&
16832 	    TSTMP_GT(cts, rack->r_ctl.rc_went_idle_time)) {
16833 		idle = cts - rack->r_ctl.rc_went_idle_time;
16834 		if (idle > rack_min_probertt_hold) {
16835 			/* Count as a probe rtt */
16836 			if (rack->in_probe_rtt == 0) {
16837 				rack->r_ctl.rc_lower_rtt_us_cts = cts;
16838 				rack->r_ctl.rc_time_probertt_entered = rack->r_ctl.rc_lower_rtt_us_cts;
16839 				rack->r_ctl.rc_time_probertt_starts = rack->r_ctl.rc_lower_rtt_us_cts;
16840 				rack->r_ctl.rc_time_of_last_probertt = rack->r_ctl.rc_lower_rtt_us_cts;
16841 			} else {
16842 				rack_exit_probertt(rack, cts);
16843 			}
16844 		}
16845 		idle = 0;
16846 	}
16847 	if (rack_use_fsb && (rack->r_fsb_inited == 0) && (rack->r_state != TCPS_CLOSED))
16848 		rack_init_fsb_block(tp, rack);
16849 again:
16850 	/*
16851 	 * If we've recently taken a timeout, snd_max will be greater than
16852 	 * snd_nxt.  There may be SACK information that allows us to avoid
16853 	 * resending already delivered data.  Adjust snd_nxt accordingly.
16854 	 */
16855 	sendalot = 0;
16856 	cts = tcp_get_usecs(&tv);
16857 	ms_cts = tcp_tv_to_mssectick(&tv);
16858 	tso = 0;
16859 	mtu = 0;
16860 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
16861 	minseg = segsiz;
16862 	if (rack->r_ctl.rc_pace_max_segs == 0)
16863 		pace_max_seg = rack->rc_user_set_max_segs * segsiz;
16864 	else
16865 		pace_max_seg = rack->r_ctl.rc_pace_max_segs;
16866 	sb_offset = tp->snd_max - tp->snd_una;
16867 	cwnd_to_use = rack->r_ctl.cwnd_to_use = tp->snd_cwnd;
16868 	flags = tcp_outflags[tp->t_state];
16869 	while (rack->rc_free_cnt < rack_free_cache) {
16870 		rsm = rack_alloc(rack);
16871 		if (rsm == NULL) {
16872 			if (inp->inp_hpts_calls)
16873 				/* Retry in a ms */
16874 				slot = (1 * HPTS_USEC_IN_MSEC);
16875 			so = inp->inp_socket;
16876 			sb = &so->so_snd;
16877 			goto just_return_nolock;
16878 		}
16879 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_free, rsm, r_tnext);
16880 		rack->rc_free_cnt++;
16881 		rsm = NULL;
16882 	}
16883 	if (inp->inp_hpts_calls)
16884 		inp->inp_hpts_calls = 0;
16885 	sack_rxmit = 0;
16886 	len = 0;
16887 	rsm = NULL;
16888 	if (flags & TH_RST) {
16889 		SOCKBUF_LOCK(&inp->inp_socket->so_snd);
16890 		so = inp->inp_socket;
16891 		sb = &so->so_snd;
16892 		goto send;
16893 	}
16894 	if (rack->r_ctl.rc_resend) {
16895 		/* Retransmit timer */
16896 		rsm = rack->r_ctl.rc_resend;
16897 		rack->r_ctl.rc_resend = NULL;
16898 		len = rsm->r_end - rsm->r_start;
16899 		sack_rxmit = 1;
16900 		sendalot = 0;
16901 		KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start),
16902 			("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p",
16903 			 __func__, __LINE__,
16904 			 rsm->r_start, tp->snd_una, tp, rack, rsm));
16905 		sb_offset = rsm->r_start - tp->snd_una;
16906 		if (len >= segsiz)
16907 			len = segsiz;
16908 	} else if (rack->r_collapse_point_valid &&
16909 		   ((rsm = rack_check_collapsed(rack, cts)) != NULL)) {
16910 		/*
16911 		 * If an RSM is returned then enough time has passed
16912 		 * for us to retransmit it. Move up the collapse point,
16913 		 * since this rsm has its chance to retransmit now.
16914 		 */
16915 		rack_trace_point(rack, RACK_TP_COLLAPSED_RXT);
16916 		rack->r_ctl.last_collapse_point = rsm->r_end;
16917 		/* Are we done? */
16918 		if (SEQ_GEQ(rack->r_ctl.last_collapse_point,
16919 			    rack->r_ctl.high_collapse_point))
16920 			rack->r_collapse_point_valid = 0;
16921 		sack_rxmit = 1;
16922 		/* We are not doing a TLP */
16923 		doing_tlp = 0;
16924 		len = rsm->r_end - rsm->r_start;
16925 		sb_offset = rsm->r_start - tp->snd_una;
16926 		sendalot = 0;
16927 		if ((rack->full_size_rxt == 0) &&
16928 		    (rack->shape_rxt_to_pacing_min == 0) &&
16929 		    (len >= segsiz))
16930 			len = segsiz;
16931 	} else if ((rsm = tcp_rack_output(tp, rack, cts)) != NULL) {
16932 		/* We have a retransmit that takes precedence */
16933 		if ((!IN_FASTRECOVERY(tp->t_flags)) &&
16934 		    ((rsm->r_flags & RACK_MUST_RXT) == 0) &&
16935 		    ((tp->t_flags & TF_WASFRECOVERY) == 0)) {
16936 			/* Enter recovery if not induced by a time-out */
16937 			rack_cong_signal(tp, CC_NDUPACK, tp->snd_una, __LINE__);
16938 		}
16939 #ifdef INVARIANTS
16940 		if (SEQ_LT(rsm->r_start, tp->snd_una)) {
16941 			panic("Huh, tp:%p rack:%p rsm:%p start:%u < snd_una:%u\n",
16942 			      tp, rack, rsm, rsm->r_start, tp->snd_una);
16943 		}
16944 #endif
16945 		len = rsm->r_end - rsm->r_start;
16946 		KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start),
16947 			("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p",
16948 			 __func__, __LINE__,
16949 			 rsm->r_start, tp->snd_una, tp, rack, rsm));
16950 		sb_offset = rsm->r_start - tp->snd_una;
16951 		sendalot = 0;
16952 		if (len >= segsiz)
16953 			len = segsiz;
16954 		if (len > 0) {
16955 			sack_rxmit = 1;
16956 			KMOD_TCPSTAT_INC(tcps_sack_rexmits);
16957 			KMOD_TCPSTAT_ADD(tcps_sack_rexmit_bytes,
16958 			    min(len, segsiz));
16959 		}
16960 	} else if (rack->r_ctl.rc_tlpsend) {
16961 		/* Tail loss probe */
16962 		long cwin;
16963 		long tlen;
16964 
16965 		/*
16966 		 * Check if we can do a TLP with a RACK'd packet
16967 		 * this can happen if we are not doing the rack
16968 		 * cheat and we skipped to a TLP and it
16969 		 * went off.
16970 		 */
16971 		rsm = rack->r_ctl.rc_tlpsend;
16972 		/* We are doing a TLP make sure the flag is preent */
16973 		rsm->r_flags |= RACK_TLP;
16974 		rack->r_ctl.rc_tlpsend = NULL;
16975 		sack_rxmit = 1;
16976 		tlen = rsm->r_end - rsm->r_start;
16977 		if (tlen > segsiz)
16978 			tlen = segsiz;
16979 		KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start),
16980 			("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p",
16981 			 __func__, __LINE__,
16982 			 rsm->r_start, tp->snd_una, tp, rack, rsm));
16983 		sb_offset = rsm->r_start - tp->snd_una;
16984 		cwin = min(tp->snd_wnd, tlen);
16985 		len = cwin;
16986 	}
16987 	if (rack->r_must_retran &&
16988 	    (doing_tlp == 0) &&
16989 	    (SEQ_GT(tp->snd_max, tp->snd_una)) &&
16990 	    (rsm == NULL)) {
16991 		/*
16992 		 * There are two different ways that we
16993 		 * can get into this block:
16994 		 * a) This is a non-sack connection, we had a time-out
16995 		 *    and thus r_must_retran was set and everything
16996 		 *    left outstanding as been marked for retransmit.
16997 		 * b) The MTU of the path shrank, so that everything
16998 		 *    was marked to be retransmitted with the smaller
16999 		 *    mtu and r_must_retran was set.
17000 		 *
17001 		 * This means that we expect the sendmap (outstanding)
17002 		 * to all be marked must. We can use the tmap to
17003 		 * look at them.
17004 		 *
17005 		 */
17006 		int sendwin, flight;
17007 
17008 		sendwin = min(tp->snd_wnd, tp->snd_cwnd);
17009 		flight = ctf_flight_size(tp, rack->r_ctl.rc_out_at_rto);
17010 		if (flight >= sendwin) {
17011 			/*
17012 			 * We can't send yet.
17013 			 */
17014 			so = inp->inp_socket;
17015 			sb = &so->so_snd;
17016 			goto just_return_nolock;
17017 		}
17018 		/*
17019 		 * This is the case a/b mentioned above. All
17020 		 * outstanding/not-acked should be marked.
17021 		 * We can use the tmap to find them.
17022 		 */
17023 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
17024 		if (rsm == NULL) {
17025 			/* TSNH */
17026 			rack->r_must_retran = 0;
17027 			rack->r_ctl.rc_out_at_rto = 0;
17028 			so = inp->inp_socket;
17029 			sb = &so->so_snd;
17030 			goto just_return_nolock;
17031 		}
17032 		if ((rsm->r_flags & RACK_MUST_RXT) == 0) {
17033 			/*
17034 			 * The first one does not have the flag, did we collapse
17035 			 * further up in our list?
17036 			 */
17037 			rack->r_must_retran = 0;
17038 			rack->r_ctl.rc_out_at_rto = 0;
17039 			rsm = NULL;
17040 			sack_rxmit = 0;
17041 		} else {
17042 			sack_rxmit = 1;
17043 			len = rsm->r_end - rsm->r_start;
17044 			sb_offset = rsm->r_start - tp->snd_una;
17045 			sendalot = 0;
17046 			if ((rack->full_size_rxt == 0) &&
17047 			    (rack->shape_rxt_to_pacing_min == 0) &&
17048 			    (len >= segsiz))
17049 				len = segsiz;
17050 			/*
17051 			 * Delay removing the flag RACK_MUST_RXT so
17052 			 * that the fastpath for retransmit will
17053 			 * work with this rsm.
17054 			 */
17055 		}
17056 	}
17057 	/*
17058 	 * Enforce a connection sendmap count limit if set
17059 	 * as long as we are not retransmiting.
17060 	 */
17061 	if ((rsm == NULL) &&
17062 	    (rack->do_detection == 0) &&
17063 	    (V_tcp_map_entries_limit > 0) &&
17064 	    (rack->r_ctl.rc_num_maps_alloced >= V_tcp_map_entries_limit)) {
17065 		counter_u64_add(rack_to_alloc_limited, 1);
17066 		if (!rack->alloc_limit_reported) {
17067 			rack->alloc_limit_reported = 1;
17068 			counter_u64_add(rack_alloc_limited_conns, 1);
17069 		}
17070 		so = inp->inp_socket;
17071 		sb = &so->so_snd;
17072 		goto just_return_nolock;
17073 	}
17074 	if (rsm && (rsm->r_flags & RACK_HAS_FIN)) {
17075 		/* we are retransmitting the fin */
17076 		len--;
17077 		if (len) {
17078 			/*
17079 			 * When retransmitting data do *not* include the
17080 			 * FIN. This could happen from a TLP probe.
17081 			 */
17082 			flags &= ~TH_FIN;
17083 		}
17084 	}
17085 	if (rsm && rack->r_fsb_inited && rack_use_rsm_rfo &&
17086 	    ((rsm->r_flags & RACK_HAS_FIN) == 0)) {
17087 		int ret;
17088 
17089 		ret = rack_fast_rsm_output(tp, rack, rsm, ts_val, cts, ms_cts, &tv, len, doing_tlp);
17090 		if (ret == 0)
17091 			return (0);
17092 	}
17093 	so = inp->inp_socket;
17094 	sb = &so->so_snd;
17095 	if (do_a_prefetch == 0) {
17096 		kern_prefetch(sb, &do_a_prefetch);
17097 		do_a_prefetch = 1;
17098 	}
17099 #ifdef NETFLIX_SHARED_CWND
17100 	if ((tp->t_flags2 & TF2_TCP_SCWND_ALLOWED) &&
17101 	    rack->rack_enable_scwnd) {
17102 		/* We are doing cwnd sharing */
17103 		if (rack->gp_ready &&
17104 		    (rack->rack_attempted_scwnd == 0) &&
17105 		    (rack->r_ctl.rc_scw == NULL) &&
17106 		    tp->t_lib) {
17107 			/* The pcbid is in, lets make an attempt */
17108 			counter_u64_add(rack_try_scwnd, 1);
17109 			rack->rack_attempted_scwnd = 1;
17110 			rack->r_ctl.rc_scw = tcp_shared_cwnd_alloc(tp,
17111 								   &rack->r_ctl.rc_scw_index,
17112 								   segsiz);
17113 		}
17114 		if (rack->r_ctl.rc_scw &&
17115 		    (rack->rack_scwnd_is_idle == 1) &&
17116 		    sbavail(&so->so_snd)) {
17117 			/* we are no longer out of data */
17118 			tcp_shared_cwnd_active(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
17119 			rack->rack_scwnd_is_idle = 0;
17120 		}
17121 		if (rack->r_ctl.rc_scw) {
17122 			/* First lets update and get the cwnd */
17123 			rack->r_ctl.cwnd_to_use = cwnd_to_use = tcp_shared_cwnd_update(rack->r_ctl.rc_scw,
17124 								    rack->r_ctl.rc_scw_index,
17125 								    tp->snd_cwnd, tp->snd_wnd, segsiz);
17126 		}
17127 	}
17128 #endif
17129 	/*
17130 	 * Get standard flags, and add SYN or FIN if requested by 'hidden'
17131 	 * state flags.
17132 	 */
17133 	if (tp->t_flags & TF_NEEDFIN)
17134 		flags |= TH_FIN;
17135 	if (tp->t_flags & TF_NEEDSYN)
17136 		flags |= TH_SYN;
17137 	if ((sack_rxmit == 0) && (prefetch_rsm == 0)) {
17138 		void *end_rsm;
17139 		end_rsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_tmap, rack_sendmap, r_tnext);
17140 		if (end_rsm)
17141 			kern_prefetch(end_rsm, &prefetch_rsm);
17142 		prefetch_rsm = 1;
17143 	}
17144 	SOCKBUF_LOCK(sb);
17145 	/*
17146 	 * If snd_nxt == snd_max and we have transmitted a FIN, the
17147 	 * sb_offset will be > 0 even if so_snd.sb_cc is 0, resulting in a
17148 	 * negative length.  This can also occur when TCP opens up its
17149 	 * congestion window while receiving additional duplicate acks after
17150 	 * fast-retransmit because TCP will reset snd_nxt to snd_max after
17151 	 * the fast-retransmit.
17152 	 *
17153 	 * In the normal retransmit-FIN-only case, however, snd_nxt will be
17154 	 * set to snd_una, the sb_offset will be 0, and the length may wind
17155 	 * up 0.
17156 	 *
17157 	 * If sack_rxmit is true we are retransmitting from the scoreboard
17158 	 * in which case len is already set.
17159 	 */
17160 	if ((sack_rxmit == 0) &&
17161 	    (TCPS_HAVEESTABLISHED(tp->t_state) || IS_FASTOPEN(tp->t_flags))) {
17162 		uint32_t avail;
17163 
17164 		avail = sbavail(sb);
17165 		if (SEQ_GT(tp->snd_nxt, tp->snd_una) && avail)
17166 			sb_offset = tp->snd_nxt - tp->snd_una;
17167 		else
17168 			sb_offset = 0;
17169 		if ((IN_FASTRECOVERY(tp->t_flags) == 0) || rack->rack_no_prr) {
17170 			if (rack->r_ctl.rc_tlp_new_data) {
17171 				/* TLP is forcing out new data */
17172 				if (rack->r_ctl.rc_tlp_new_data > (uint32_t) (avail - sb_offset)) {
17173 					rack->r_ctl.rc_tlp_new_data = (uint32_t) (avail - sb_offset);
17174 				}
17175 				if ((rack->r_ctl.rc_tlp_new_data + sb_offset) > tp->snd_wnd) {
17176 					if (tp->snd_wnd > sb_offset)
17177 						len = tp->snd_wnd - sb_offset;
17178 					else
17179 						len = 0;
17180 				} else {
17181 					len = rack->r_ctl.rc_tlp_new_data;
17182 				}
17183 				rack->r_ctl.rc_tlp_new_data = 0;
17184 			}  else {
17185 				len = rack_what_can_we_send(tp, rack, cwnd_to_use, avail, sb_offset);
17186 			}
17187 			if ((rack->r_ctl.crte == NULL) && IN_FASTRECOVERY(tp->t_flags) && (len > segsiz)) {
17188 				/*
17189 				 * For prr=off, we need to send only 1 MSS
17190 				 * at a time. We do this because another sack could
17191 				 * be arriving that causes us to send retransmits and
17192 				 * we don't want to be on a long pace due to a larger send
17193 				 * that keeps us from sending out the retransmit.
17194 				 */
17195 				len = segsiz;
17196 			}
17197 		} else {
17198 			uint32_t outstanding;
17199 			/*
17200 			 * We are inside of a Fast recovery episode, this
17201 			 * is caused by a SACK or 3 dup acks. At this point
17202 			 * we have sent all the retransmissions and we rely
17203 			 * on PRR to dictate what we will send in the form of
17204 			 * new data.
17205 			 */
17206 
17207 			outstanding = tp->snd_max - tp->snd_una;
17208 			if ((rack->r_ctl.rc_prr_sndcnt + outstanding) > tp->snd_wnd) {
17209 				if (tp->snd_wnd > outstanding) {
17210 					len = tp->snd_wnd - outstanding;
17211 					/* Check to see if we have the data */
17212 					if ((sb_offset + len) > avail) {
17213 						/* It does not all fit */
17214 						if (avail > sb_offset)
17215 							len = avail - sb_offset;
17216 						else
17217 							len = 0;
17218 					}
17219 				} else {
17220 					len = 0;
17221 				}
17222 			} else if (avail > sb_offset) {
17223 				len = avail - sb_offset;
17224 			} else {
17225 				len = 0;
17226 			}
17227 			if (len > 0) {
17228 				if (len > rack->r_ctl.rc_prr_sndcnt) {
17229 					len = rack->r_ctl.rc_prr_sndcnt;
17230 				}
17231 				if (len > 0) {
17232 					sub_from_prr = 1;
17233 				}
17234 			}
17235 			if (len > segsiz) {
17236 				/*
17237 				 * We should never send more than a MSS when
17238 				 * retransmitting or sending new data in prr
17239 				 * mode unless the override flag is on. Most
17240 				 * likely the PRR algorithm is not going to
17241 				 * let us send a lot as well :-)
17242 				 */
17243 				if (rack->r_ctl.rc_prr_sendalot == 0) {
17244 					len = segsiz;
17245 				}
17246 			} else if (len < segsiz) {
17247 				/*
17248 				 * Do we send any? The idea here is if the
17249 				 * send empty's the socket buffer we want to
17250 				 * do it. However if not then lets just wait
17251 				 * for our prr_sndcnt to get bigger.
17252 				 */
17253 				long leftinsb;
17254 
17255 				leftinsb = sbavail(sb) - sb_offset;
17256 				if (leftinsb > len) {
17257 					/* This send does not empty the sb */
17258 					len = 0;
17259 				}
17260 			}
17261 		}
17262 	} else if (!TCPS_HAVEESTABLISHED(tp->t_state)) {
17263 		/*
17264 		 * If you have not established
17265 		 * and are not doing FAST OPEN
17266 		 * no data please.
17267 		 */
17268 		if ((sack_rxmit == 0) &&
17269 		    (!IS_FASTOPEN(tp->t_flags))){
17270 			len = 0;
17271 			sb_offset = 0;
17272 		}
17273 	}
17274 	if (prefetch_so_done == 0) {
17275 		kern_prefetch(so, &prefetch_so_done);
17276 		prefetch_so_done = 1;
17277 	}
17278 	/*
17279 	 * Lop off SYN bit if it has already been sent.  However, if this is
17280 	 * SYN-SENT state and if segment contains data and if we don't know
17281 	 * that foreign host supports TAO, suppress sending segment.
17282 	 */
17283 	if ((flags & TH_SYN) && SEQ_GT(tp->snd_nxt, tp->snd_una) &&
17284 	    ((sack_rxmit == 0) && (tp->t_rxtshift == 0))) {
17285 		/*
17286 		 * When sending additional segments following a TFO SYN|ACK,
17287 		 * do not include the SYN bit.
17288 		 */
17289 		if (IS_FASTOPEN(tp->t_flags) &&
17290 		    (tp->t_state == TCPS_SYN_RECEIVED))
17291 			flags &= ~TH_SYN;
17292 	}
17293 	/*
17294 	 * Be careful not to send data and/or FIN on SYN segments. This
17295 	 * measure is needed to prevent interoperability problems with not
17296 	 * fully conformant TCP implementations.
17297 	 */
17298 	if ((flags & TH_SYN) && (tp->t_flags & TF_NOOPT)) {
17299 		len = 0;
17300 		flags &= ~TH_FIN;
17301 	}
17302 	/*
17303 	 * On TFO sockets, ensure no data is sent in the following cases:
17304 	 *
17305 	 *  - When retransmitting SYN|ACK on a passively-created socket
17306 	 *
17307 	 *  - When retransmitting SYN on an actively created socket
17308 	 *
17309 	 *  - When sending a zero-length cookie (cookie request) on an
17310 	 *    actively created socket
17311 	 *
17312 	 *  - When the socket is in the CLOSED state (RST is being sent)
17313 	 */
17314 	if (IS_FASTOPEN(tp->t_flags) &&
17315 	    (((flags & TH_SYN) && (tp->t_rxtshift > 0)) ||
17316 	     ((tp->t_state == TCPS_SYN_SENT) &&
17317 	      (tp->t_tfo_client_cookie_len == 0)) ||
17318 	     (flags & TH_RST))) {
17319 		sack_rxmit = 0;
17320 		len = 0;
17321 	}
17322 	/* Without fast-open there should never be data sent on a SYN */
17323 	if ((flags & TH_SYN) && (!IS_FASTOPEN(tp->t_flags))) {
17324 		tp->snd_nxt = tp->iss;
17325 		len = 0;
17326 	}
17327 	if ((len > segsiz) && (tcp_dsack_block_exists(tp))) {
17328 		/* We only send 1 MSS if we have a DSACK block */
17329 		add_flag |= RACK_SENT_W_DSACK;
17330 		len = segsiz;
17331 	}
17332 	orig_len = len;
17333 	if (len <= 0) {
17334 		/*
17335 		 * If FIN has been sent but not acked, but we haven't been
17336 		 * called to retransmit, len will be < 0.  Otherwise, window
17337 		 * shrank after we sent into it.  If window shrank to 0,
17338 		 * cancel pending retransmit, pull snd_nxt back to (closed)
17339 		 * window, and set the persist timer if it isn't already
17340 		 * going.  If the window didn't close completely, just wait
17341 		 * for an ACK.
17342 		 *
17343 		 * We also do a general check here to ensure that we will
17344 		 * set the persist timer when we have data to send, but a
17345 		 * 0-byte window. This makes sure the persist timer is set
17346 		 * even if the packet hits one of the "goto send" lines
17347 		 * below.
17348 		 */
17349 		len = 0;
17350 		if ((tp->snd_wnd == 0) &&
17351 		    (TCPS_HAVEESTABLISHED(tp->t_state)) &&
17352 		    (tp->snd_una == tp->snd_max) &&
17353 		    (sb_offset < (int)sbavail(sb))) {
17354 			rack_enter_persist(tp, rack, cts);
17355 		}
17356 	} else if ((rsm == NULL) &&
17357 		   (doing_tlp == 0) &&
17358 		   (len < pace_max_seg)) {
17359 		/*
17360 		 * We are not sending a maximum sized segment for
17361 		 * some reason. Should we not send anything (think
17362 		 * sws or persists)?
17363 		 */
17364 		if ((tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), minseg)) &&
17365 		    (TCPS_HAVEESTABLISHED(tp->t_state)) &&
17366 		    (len < minseg) &&
17367 		    (len < (int)(sbavail(sb) - sb_offset))) {
17368 			/*
17369 			 * Here the rwnd is less than
17370 			 * the minimum pacing size, this is not a retransmit,
17371 			 * we are established and
17372 			 * the send is not the last in the socket buffer
17373 			 * we send nothing, and we may enter persists
17374 			 * if nothing is outstanding.
17375 			 */
17376 			len = 0;
17377 			if (tp->snd_max == tp->snd_una) {
17378 				/*
17379 				 * Nothing out we can
17380 				 * go into persists.
17381 				 */
17382 				rack_enter_persist(tp, rack, cts);
17383 			}
17384 		     } else if ((cwnd_to_use >= max(minseg, (segsiz * 4))) &&
17385 			   (ctf_flight_size(tp, rack->r_ctl.rc_sacked) > (2 * segsiz)) &&
17386 			   (len < (int)(sbavail(sb) - sb_offset)) &&
17387 			   (len < minseg)) {
17388 			/*
17389 			 * Here we are not retransmitting, and
17390 			 * the cwnd is not so small that we could
17391 			 * not send at least a min size (rxt timer
17392 			 * not having gone off), We have 2 segments or
17393 			 * more already in flight, its not the tail end
17394 			 * of the socket buffer  and the cwnd is blocking
17395 			 * us from sending out a minimum pacing segment size.
17396 			 * Lets not send anything.
17397 			 */
17398 			len = 0;
17399 		} else if (((tp->snd_wnd - ctf_outstanding(tp)) <
17400 			    min((rack->r_ctl.rc_high_rwnd/2), minseg)) &&
17401 			   (ctf_flight_size(tp, rack->r_ctl.rc_sacked) > (2 * segsiz)) &&
17402 			   (len < (int)(sbavail(sb) - sb_offset)) &&
17403 			   (TCPS_HAVEESTABLISHED(tp->t_state))) {
17404 			/*
17405 			 * Here we have a send window but we have
17406 			 * filled it up and we can't send another pacing segment.
17407 			 * We also have in flight more than 2 segments
17408 			 * and we are not completing the sb i.e. we allow
17409 			 * the last bytes of the sb to go out even if
17410 			 * its not a full pacing segment.
17411 			 */
17412 			len = 0;
17413 		} else if ((rack->r_ctl.crte != NULL) &&
17414 			   (tp->snd_wnd >= (pace_max_seg * max(1, rack_hw_rwnd_factor))) &&
17415 			   (cwnd_to_use >= (pace_max_seg + (4 * segsiz))) &&
17416 			   (ctf_flight_size(tp, rack->r_ctl.rc_sacked) >= (2 * segsiz)) &&
17417 			   (len < (int)(sbavail(sb) - sb_offset))) {
17418 			/*
17419 			 * Here we are doing hardware pacing, this is not a TLP,
17420 			 * we are not sending a pace max segment size, there is rwnd
17421 			 * room to send at least N pace_max_seg, the cwnd is greater
17422 			 * than or equal to a full pacing segments plus 4 mss and we have 2 or
17423 			 * more segments in flight and its not the tail of the socket buffer.
17424 			 *
17425 			 * We don't want to send instead we need to get more ack's in to
17426 			 * allow us to send a full pacing segment. Normally, if we are pacing
17427 			 * about the right speed, we should have finished our pacing
17428 			 * send as most of the acks have come back if we are at the
17429 			 * right rate. This is a bit fuzzy since return path delay
17430 			 * can delay the acks, which is why we want to make sure we
17431 			 * have cwnd space to have a bit more than a max pace segments in flight.
17432 			 *
17433 			 * If we have not gotten our acks back we are pacing at too high a
17434 			 * rate delaying will not hurt and will bring our GP estimate down by
17435 			 * injecting the delay. If we don't do this we will send
17436 			 * 2 MSS out in response to the acks being clocked in which
17437 			 * defeats the point of hw-pacing (i.e. to help us get
17438 			 * larger TSO's out).
17439 			 */
17440 			len = 0;
17441 
17442 		}
17443 
17444 	}
17445 	/* len will be >= 0 after this point. */
17446 	KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__));
17447 	rack_sndbuf_autoscale(rack);
17448 	/*
17449 	 * Decide if we can use TCP Segmentation Offloading (if supported by
17450 	 * hardware).
17451 	 *
17452 	 * TSO may only be used if we are in a pure bulk sending state.  The
17453 	 * presence of TCP-MD5, SACK retransmits, SACK advertizements and IP
17454 	 * options prevent using TSO.  With TSO the TCP header is the same
17455 	 * (except for the sequence number) for all generated packets.  This
17456 	 * makes it impossible to transmit any options which vary per
17457 	 * generated segment or packet.
17458 	 *
17459 	 * IPv4 handling has a clear separation of ip options and ip header
17460 	 * flags while IPv6 combines both in in6p_outputopts. ip6_optlen() does
17461 	 * the right thing below to provide length of just ip options and thus
17462 	 * checking for ipoptlen is enough to decide if ip options are present.
17463 	 */
17464 	ipoptlen = 0;
17465 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
17466 	/*
17467 	 * Pre-calculate here as we save another lookup into the darknesses
17468 	 * of IPsec that way and can actually decide if TSO is ok.
17469 	 */
17470 #ifdef INET6
17471 	if (isipv6 && IPSEC_ENABLED(ipv6))
17472 		ipsec_optlen = IPSEC_HDRSIZE(ipv6, inp);
17473 #ifdef INET
17474 	else
17475 #endif
17476 #endif				/* INET6 */
17477 #ifdef INET
17478 		if (IPSEC_ENABLED(ipv4))
17479 			ipsec_optlen = IPSEC_HDRSIZE(ipv4, inp);
17480 #endif				/* INET */
17481 #endif
17482 
17483 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
17484 	ipoptlen += ipsec_optlen;
17485 #endif
17486 	if ((tp->t_flags & TF_TSO) && V_tcp_do_tso && len > segsiz &&
17487 	    (tp->t_port == 0) &&
17488 	    ((tp->t_flags & TF_SIGNATURE) == 0) &&
17489 	    tp->rcv_numsacks == 0 && sack_rxmit == 0 &&
17490 	    ipoptlen == 0)
17491 		tso = 1;
17492 	{
17493 		uint32_t outstanding __unused;
17494 
17495 		outstanding = tp->snd_max - tp->snd_una;
17496 		if (tp->t_flags & TF_SENTFIN) {
17497 			/*
17498 			 * If we sent a fin, snd_max is 1 higher than
17499 			 * snd_una
17500 			 */
17501 			outstanding--;
17502 		}
17503 		if (sack_rxmit) {
17504 			if ((rsm->r_flags & RACK_HAS_FIN) == 0)
17505 				flags &= ~TH_FIN;
17506 		} else {
17507 			if (SEQ_LT(tp->snd_nxt + len, tp->snd_una +
17508 				   sbused(sb)))
17509 				flags &= ~TH_FIN;
17510 		}
17511 	}
17512 	recwin = lmin(lmax(sbspace(&so->so_rcv), 0),
17513 	    (long)TCP_MAXWIN << tp->rcv_scale);
17514 
17515 	/*
17516 	 * Sender silly window avoidance.   We transmit under the following
17517 	 * conditions when len is non-zero:
17518 	 *
17519 	 * - We have a full segment (or more with TSO) - This is the last
17520 	 * buffer in a write()/send() and we are either idle or running
17521 	 * NODELAY - we've timed out (e.g. persist timer) - we have more
17522 	 * then 1/2 the maximum send window's worth of data (receiver may be
17523 	 * limited the window size) - we need to retransmit
17524 	 */
17525 	if (len) {
17526 		if (len >= segsiz) {
17527 			goto send;
17528 		}
17529 		/*
17530 		 * NOTE! on localhost connections an 'ack' from the remote
17531 		 * end may occur synchronously with the output and cause us
17532 		 * to flush a buffer queued with moretocome.  XXX
17533 		 *
17534 		 */
17535 		if (!(tp->t_flags & TF_MORETOCOME) &&	/* normal case */
17536 		    (idle || (tp->t_flags & TF_NODELAY)) &&
17537 		    ((uint32_t)len + (uint32_t)sb_offset >= sbavail(sb)) &&
17538 		    (tp->t_flags & TF_NOPUSH) == 0) {
17539 			pass = 2;
17540 			goto send;
17541 		}
17542 		if ((tp->snd_una == tp->snd_max) && len) {	/* Nothing outstanding */
17543 			pass = 22;
17544 			goto send;
17545 		}
17546 		if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) {
17547 			pass = 4;
17548 			goto send;
17549 		}
17550 		if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {	/* retransmit case */
17551 			pass = 5;
17552 			goto send;
17553 		}
17554 		if (sack_rxmit) {
17555 			pass = 6;
17556 			goto send;
17557 		}
17558 		if (((tp->snd_wnd - ctf_outstanding(tp)) < segsiz) &&
17559 		    (ctf_outstanding(tp) < (segsiz * 2))) {
17560 			/*
17561 			 * We have less than two MSS outstanding (delayed ack)
17562 			 * and our rwnd will not let us send a full sized
17563 			 * MSS. Lets go ahead and let this small segment
17564 			 * out because we want to try to have at least two
17565 			 * packets inflight to not be caught by delayed ack.
17566 			 */
17567 			pass = 12;
17568 			goto send;
17569 		}
17570 	}
17571 	/*
17572 	 * Sending of standalone window updates.
17573 	 *
17574 	 * Window updates are important when we close our window due to a
17575 	 * full socket buffer and are opening it again after the application
17576 	 * reads data from it.  Once the window has opened again and the
17577 	 * remote end starts to send again the ACK clock takes over and
17578 	 * provides the most current window information.
17579 	 *
17580 	 * We must avoid the silly window syndrome whereas every read from
17581 	 * the receive buffer, no matter how small, causes a window update
17582 	 * to be sent.  We also should avoid sending a flurry of window
17583 	 * updates when the socket buffer had queued a lot of data and the
17584 	 * application is doing small reads.
17585 	 *
17586 	 * Prevent a flurry of pointless window updates by only sending an
17587 	 * update when we can increase the advertized window by more than
17588 	 * 1/4th of the socket buffer capacity.  When the buffer is getting
17589 	 * full or is very small be more aggressive and send an update
17590 	 * whenever we can increase by two mss sized segments. In all other
17591 	 * situations the ACK's to new incoming data will carry further
17592 	 * window increases.
17593 	 *
17594 	 * Don't send an independent window update if a delayed ACK is
17595 	 * pending (it will get piggy-backed on it) or the remote side
17596 	 * already has done a half-close and won't send more data.  Skip
17597 	 * this if the connection is in T/TCP half-open state.
17598 	 */
17599 	if (recwin > 0 && !(tp->t_flags & TF_NEEDSYN) &&
17600 	    !(tp->t_flags & TF_DELACK) &&
17601 	    !TCPS_HAVERCVDFIN(tp->t_state)) {
17602 		/*
17603 		 * "adv" is the amount we could increase the window, taking
17604 		 * into account that we are limited by TCP_MAXWIN <<
17605 		 * tp->rcv_scale.
17606 		 */
17607 		int32_t adv;
17608 		int oldwin;
17609 
17610 		adv = recwin;
17611 		if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt)) {
17612 			oldwin = (tp->rcv_adv - tp->rcv_nxt);
17613 			if (adv > oldwin)
17614 			    adv -= oldwin;
17615 			else {
17616 				/* We can't increase the window */
17617 				adv = 0;
17618 			}
17619 		} else
17620 			oldwin = 0;
17621 
17622 		/*
17623 		 * If the new window size ends up being the same as or less
17624 		 * than the old size when it is scaled, then don't force
17625 		 * a window update.
17626 		 */
17627 		if (oldwin >> tp->rcv_scale >= (adv + oldwin) >> tp->rcv_scale)
17628 			goto dontupdate;
17629 
17630 		if (adv >= (int32_t)(2 * segsiz) &&
17631 		    (adv >= (int32_t)(so->so_rcv.sb_hiwat / 4) ||
17632 		     recwin <= (int32_t)(so->so_rcv.sb_hiwat / 8) ||
17633 		     so->so_rcv.sb_hiwat <= 8 * segsiz)) {
17634 			pass = 7;
17635 			goto send;
17636 		}
17637 		if (2 * adv >= (int32_t) so->so_rcv.sb_hiwat) {
17638 			pass = 23;
17639 			goto send;
17640 		}
17641 	}
17642 dontupdate:
17643 
17644 	/*
17645 	 * Send if we owe the peer an ACK, RST, SYN, or urgent data.  ACKNOW
17646 	 * is also a catch-all for the retransmit timer timeout case.
17647 	 */
17648 	if (tp->t_flags & TF_ACKNOW) {
17649 		pass = 8;
17650 		goto send;
17651 	}
17652 	if (((flags & TH_SYN) && (tp->t_flags & TF_NEEDSYN) == 0)) {
17653 		pass = 9;
17654 		goto send;
17655 	}
17656 	/*
17657 	 * If our state indicates that FIN should be sent and we have not
17658 	 * yet done so, then we need to send.
17659 	 */
17660 	if ((flags & TH_FIN) &&
17661 	    (tp->snd_nxt == tp->snd_una)) {
17662 		pass = 11;
17663 		goto send;
17664 	}
17665 	/*
17666 	 * No reason to send a segment, just return.
17667 	 */
17668 just_return:
17669 	SOCKBUF_UNLOCK(sb);
17670 just_return_nolock:
17671 	{
17672 		int app_limited = CTF_JR_SENT_DATA;
17673 
17674 		if (tot_len_this_send > 0) {
17675 			/* Make sure snd_nxt is up to max */
17676 			rack->r_ctl.fsb.recwin = recwin;
17677 			slot = rack_get_pacing_delay(rack, tp, tot_len_this_send, NULL, segsiz);
17678 			if ((error == 0) &&
17679 			    rack_use_rfo &&
17680 			    ((flags & (TH_SYN|TH_FIN)) == 0) &&
17681 			    (ipoptlen == 0) &&
17682 			    (tp->snd_nxt == tp->snd_max) &&
17683 			    (tp->rcv_numsacks == 0) &&
17684 			    rack->r_fsb_inited &&
17685 			    TCPS_HAVEESTABLISHED(tp->t_state) &&
17686 			    (rack->r_must_retran == 0) &&
17687 			    ((tp->t_flags & TF_NEEDFIN) == 0) &&
17688 			    (len > 0) && (orig_len > 0) &&
17689 			    (orig_len > len) &&
17690 			    ((orig_len - len) >= segsiz) &&
17691 			    ((optlen == 0) ||
17692 			     ((optlen == TCPOLEN_TSTAMP_APPA) && (to.to_flags & TOF_TS)))) {
17693 				/* We can send at least one more MSS using our fsb */
17694 
17695 				rack->r_fast_output = 1;
17696 				rack->r_ctl.fsb.m = sbsndmbuf(sb, (tp->snd_max - tp->snd_una), &rack->r_ctl.fsb.off);
17697 				rack->r_ctl.fsb.o_m_len = rack->r_ctl.fsb.m->m_len;
17698 				rack->r_ctl.fsb.tcp_flags = flags;
17699 				rack->r_ctl.fsb.left_to_send = orig_len - len;
17700 				if (hw_tls)
17701 					rack->r_ctl.fsb.hw_tls = 1;
17702 				else
17703 					rack->r_ctl.fsb.hw_tls = 0;
17704 				KASSERT((rack->r_ctl.fsb.left_to_send <= (sbavail(sb) - (tp->snd_max - tp->snd_una))),
17705 					("rack:%p left_to_send:%u sbavail:%u out:%u",
17706 					rack, rack->r_ctl.fsb.left_to_send, sbavail(sb),
17707 					 (tp->snd_max - tp->snd_una)));
17708 				if (rack->r_ctl.fsb.left_to_send < segsiz)
17709 					rack->r_fast_output = 0;
17710 				else {
17711 					if (rack->r_ctl.fsb.left_to_send == (sbavail(sb) - (tp->snd_max - tp->snd_una)))
17712 						rack->r_ctl.fsb.rfo_apply_push = 1;
17713 					else
17714 						rack->r_ctl.fsb.rfo_apply_push = 0;
17715 				}
17716 			} else
17717 				rack->r_fast_output = 0;
17718 
17719 
17720 			rack_log_fsb(rack, tp, so, flags,
17721 				     ipoptlen, orig_len, len, 0,
17722 				     1, optlen, __LINE__, 1);
17723 			if (SEQ_GT(tp->snd_max, tp->snd_nxt))
17724 				tp->snd_nxt = tp->snd_max;
17725 		} else {
17726 			int end_window = 0;
17727 			uint32_t seq = tp->gput_ack;
17728 
17729 			rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
17730 			if (rsm) {
17731 				/*
17732 				 * Mark the last sent that we just-returned (hinting
17733 				 * that delayed ack may play a role in any rtt measurement).
17734 				 */
17735 				rsm->r_just_ret = 1;
17736 			}
17737 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_JUSTRET], 1);
17738 			rack->r_ctl.rc_agg_delayed = 0;
17739 			rack->r_early = 0;
17740 			rack->r_late = 0;
17741 			rack->r_ctl.rc_agg_early = 0;
17742 			if ((ctf_outstanding(tp) +
17743 			     min(max(segsiz, (rack->r_ctl.rc_high_rwnd/2)),
17744 				 minseg)) >= tp->snd_wnd) {
17745 				/* We are limited by the rwnd */
17746 				app_limited = CTF_JR_RWND_LIMITED;
17747 				if (IN_FASTRECOVERY(tp->t_flags))
17748 				    rack->r_ctl.rc_prr_sndcnt = 0;
17749 			} else if (ctf_outstanding(tp) >= sbavail(sb)) {
17750 				/* We are limited by whats available -- app limited */
17751 				app_limited = CTF_JR_APP_LIMITED;
17752 				if (IN_FASTRECOVERY(tp->t_flags))
17753 				    rack->r_ctl.rc_prr_sndcnt = 0;
17754 			} else if ((idle == 0) &&
17755 				   ((tp->t_flags & TF_NODELAY) == 0) &&
17756 				   ((uint32_t)len + (uint32_t)sb_offset >= sbavail(sb)) &&
17757 				   (len < segsiz)) {
17758 				/*
17759 				 * No delay is not on and the
17760 				 * user is sending less than 1MSS. This
17761 				 * brings out SWS avoidance so we
17762 				 * don't send. Another app-limited case.
17763 				 */
17764 				app_limited = CTF_JR_APP_LIMITED;
17765 			} else if (tp->t_flags & TF_NOPUSH) {
17766 				/*
17767 				 * The user has requested no push of
17768 				 * the last segment and we are
17769 				 * at the last segment. Another app
17770 				 * limited case.
17771 				 */
17772 				app_limited = CTF_JR_APP_LIMITED;
17773 			} else if ((ctf_outstanding(tp) + minseg) > cwnd_to_use) {
17774 				/* Its the cwnd */
17775 				app_limited = CTF_JR_CWND_LIMITED;
17776 			} else if (IN_FASTRECOVERY(tp->t_flags) &&
17777 				   (rack->rack_no_prr == 0) &&
17778 				   (rack->r_ctl.rc_prr_sndcnt < segsiz)) {
17779 				app_limited = CTF_JR_PRR;
17780 			} else {
17781 				/* Now why here are we not sending? */
17782 #ifdef NOW
17783 #ifdef INVARIANTS
17784 				panic("rack:%p hit JR_ASSESSING case cwnd_to_use:%u?", rack, cwnd_to_use);
17785 #endif
17786 #endif
17787 				app_limited = CTF_JR_ASSESSING;
17788 			}
17789 			/*
17790 			 * App limited in some fashion, for our pacing GP
17791 			 * measurements we don't want any gap (even cwnd).
17792 			 * Close  down the measurement window.
17793 			 */
17794 			if (rack_cwnd_block_ends_measure &&
17795 			    ((app_limited == CTF_JR_CWND_LIMITED) ||
17796 			     (app_limited == CTF_JR_PRR))) {
17797 				/*
17798 				 * The reason we are not sending is
17799 				 * the cwnd (or prr). We have been configured
17800 				 * to end the measurement window in
17801 				 * this case.
17802 				 */
17803 				end_window = 1;
17804 			} else if (rack_rwnd_block_ends_measure &&
17805 				   (app_limited == CTF_JR_RWND_LIMITED)) {
17806 				/*
17807 				 * We are rwnd limited and have been
17808 				 * configured to end the measurement
17809 				 * window in this case.
17810 				 */
17811 				end_window = 1;
17812 			} else if (app_limited == CTF_JR_APP_LIMITED) {
17813 				/*
17814 				 * A true application limited period, we have
17815 				 * ran out of data.
17816 				 */
17817 				end_window = 1;
17818 			} else if (app_limited == CTF_JR_ASSESSING) {
17819 				/*
17820 				 * In the assessing case we hit the end of
17821 				 * the if/else and had no known reason
17822 				 * This will panic us under invariants..
17823 				 *
17824 				 * If we get this out in logs we need to
17825 				 * investagate which reason we missed.
17826 				 */
17827 				end_window = 1;
17828 			}
17829 			if (end_window) {
17830 				uint8_t log = 0;
17831 
17832 				/* Adjust the Gput measurement */
17833 				if ((tp->t_flags & TF_GPUTINPROG) &&
17834 				    SEQ_GT(tp->gput_ack, tp->snd_max)) {
17835 					tp->gput_ack = tp->snd_max;
17836 					if ((tp->gput_ack - tp->gput_seq) < (MIN_GP_WIN * segsiz)) {
17837 						/*
17838 						 * There is not enough to measure.
17839 						 */
17840 						tp->t_flags &= ~TF_GPUTINPROG;
17841 						rack_log_pacing_delay_calc(rack, (tp->gput_ack - tp->gput_seq) /*flex2*/,
17842 									   rack->r_ctl.rc_gp_srtt /*flex1*/,
17843 									   tp->gput_seq,
17844 									   0, 0, 18, __LINE__, NULL, 0);
17845 					} else
17846 						log = 1;
17847 				}
17848 				/* Mark the last packet has app limited */
17849 				rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
17850 				if (rsm && ((rsm->r_flags & RACK_APP_LIMITED) == 0)) {
17851 					if (rack->r_ctl.rc_app_limited_cnt == 0)
17852 						rack->r_ctl.rc_end_appl = rack->r_ctl.rc_first_appl = rsm;
17853 					else {
17854 						/*
17855 						 * Go out to the end app limited and mark
17856 						 * this new one as next and move the end_appl up
17857 						 * to this guy.
17858 						 */
17859 						if (rack->r_ctl.rc_end_appl)
17860 							rack->r_ctl.rc_end_appl->r_nseq_appl = rsm->r_start;
17861 						rack->r_ctl.rc_end_appl = rsm;
17862 					}
17863 					rsm->r_flags |= RACK_APP_LIMITED;
17864 					rack->r_ctl.rc_app_limited_cnt++;
17865 				}
17866 				if (log)
17867 					rack_log_pacing_delay_calc(rack,
17868 								   rack->r_ctl.rc_app_limited_cnt, seq,
17869 								   tp->gput_ack, 0, 0, 4, __LINE__, NULL, 0);
17870 			}
17871 		}
17872 		/* Check if we need to go into persists or not */
17873 		if ((tp->snd_max == tp->snd_una) &&
17874 		    TCPS_HAVEESTABLISHED(tp->t_state) &&
17875 		    sbavail(sb) &&
17876 		    (sbavail(sb) > tp->snd_wnd) &&
17877 		    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), minseg))) {
17878 			/* Yes lets make sure to move to persist before timer-start */
17879 			rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
17880 		}
17881 		rack_start_hpts_timer(rack, tp, cts, slot, tot_len_this_send, sup_rack);
17882 		rack_log_type_just_return(rack, cts, tot_len_this_send, slot, hpts_calling, app_limited, cwnd_to_use);
17883 	}
17884 #ifdef NETFLIX_SHARED_CWND
17885 	if ((sbavail(sb) == 0) &&
17886 	    rack->r_ctl.rc_scw) {
17887 		tcp_shared_cwnd_idle(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
17888 		rack->rack_scwnd_is_idle = 1;
17889 	}
17890 #endif
17891 #ifdef TCP_ACCOUNTING
17892 	if (tot_len_this_send > 0) {
17893 		crtsc = get_cyclecount();
17894 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
17895 			tp->tcp_cnt_counters[SND_OUT_DATA]++;
17896 		}
17897 		counter_u64_add(tcp_cnt_counters[SND_OUT_DATA], 1);
17898 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
17899 			tp->tcp_proc_time[SND_OUT_DATA] += (crtsc - ts_val);
17900 		}
17901 		counter_u64_add(tcp_proc_time[SND_OUT_DATA], (crtsc - ts_val));
17902 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
17903 			tp->tcp_cnt_counters[CNT_OF_MSS_OUT] += ((tot_len_this_send + segsiz - 1) / segsiz);
17904 		}
17905 		counter_u64_add(tcp_cnt_counters[CNT_OF_MSS_OUT], ((tot_len_this_send + segsiz - 1) / segsiz));
17906 	} else {
17907 		crtsc = get_cyclecount();
17908 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
17909 			tp->tcp_cnt_counters[SND_LIMITED]++;
17910 		}
17911 		counter_u64_add(tcp_cnt_counters[SND_LIMITED], 1);
17912 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
17913 			tp->tcp_proc_time[SND_LIMITED] += (crtsc - ts_val);
17914 		}
17915 		counter_u64_add(tcp_proc_time[SND_LIMITED], (crtsc - ts_val));
17916 	}
17917 	sched_unpin();
17918 #endif
17919 	return (0);
17920 
17921 send:
17922 	if (rsm || sack_rxmit)
17923 		counter_u64_add(rack_nfto_resend, 1);
17924 	else
17925 		counter_u64_add(rack_non_fto_send, 1);
17926 	if ((flags & TH_FIN) &&
17927 	    sbavail(sb)) {
17928 		/*
17929 		 * We do not transmit a FIN
17930 		 * with data outstanding. We
17931 		 * need to make it so all data
17932 		 * is acked first.
17933 		 */
17934 		flags &= ~TH_FIN;
17935 	}
17936 	/* Enforce stack imposed max seg size if we have one */
17937 	if (rack->r_ctl.rc_pace_max_segs &&
17938 	    (len > rack->r_ctl.rc_pace_max_segs)) {
17939 		mark = 1;
17940 		len = rack->r_ctl.rc_pace_max_segs;
17941 	}
17942 	SOCKBUF_LOCK_ASSERT(sb);
17943 	if (len > 0) {
17944 		if (len >= segsiz)
17945 			tp->t_flags2 |= TF2_PLPMTU_MAXSEGSNT;
17946 		else
17947 			tp->t_flags2 &= ~TF2_PLPMTU_MAXSEGSNT;
17948 	}
17949 	/*
17950 	 * Before ESTABLISHED, force sending of initial options unless TCP
17951 	 * set not to do any options. NOTE: we assume that the IP/TCP header
17952 	 * plus TCP options always fit in a single mbuf, leaving room for a
17953 	 * maximum link header, i.e. max_linkhdr + sizeof (struct tcpiphdr)
17954 	 * + optlen <= MCLBYTES
17955 	 */
17956 	optlen = 0;
17957 #ifdef INET6
17958 	if (isipv6)
17959 		hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
17960 	else
17961 #endif
17962 		hdrlen = sizeof(struct tcpiphdr);
17963 
17964 	/*
17965 	 * Compute options for segment. We only have to care about SYN and
17966 	 * established connection segments.  Options for SYN-ACK segments
17967 	 * are handled in TCP syncache.
17968 	 */
17969 	to.to_flags = 0;
17970 	if ((tp->t_flags & TF_NOOPT) == 0) {
17971 		/* Maximum segment size. */
17972 		if (flags & TH_SYN) {
17973 			tp->snd_nxt = tp->iss;
17974 			to.to_mss = tcp_mssopt(&inp->inp_inc);
17975 			if (tp->t_port)
17976 				to.to_mss -= V_tcp_udp_tunneling_overhead;
17977 			to.to_flags |= TOF_MSS;
17978 
17979 			/*
17980 			 * On SYN or SYN|ACK transmits on TFO connections,
17981 			 * only include the TFO option if it is not a
17982 			 * retransmit, as the presence of the TFO option may
17983 			 * have caused the original SYN or SYN|ACK to have
17984 			 * been dropped by a middlebox.
17985 			 */
17986 			if (IS_FASTOPEN(tp->t_flags) &&
17987 			    (tp->t_rxtshift == 0)) {
17988 				if (tp->t_state == TCPS_SYN_RECEIVED) {
17989 					to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN;
17990 					to.to_tfo_cookie =
17991 						(u_int8_t *)&tp->t_tfo_cookie.server;
17992 					to.to_flags |= TOF_FASTOPEN;
17993 					wanted_cookie = 1;
17994 				} else if (tp->t_state == TCPS_SYN_SENT) {
17995 					to.to_tfo_len =
17996 						tp->t_tfo_client_cookie_len;
17997 					to.to_tfo_cookie =
17998 						tp->t_tfo_cookie.client;
17999 					to.to_flags |= TOF_FASTOPEN;
18000 					wanted_cookie = 1;
18001 					/*
18002 					 * If we wind up having more data to
18003 					 * send with the SYN than can fit in
18004 					 * one segment, don't send any more
18005 					 * until the SYN|ACK comes back from
18006 					 * the other end.
18007 					 */
18008 					sendalot = 0;
18009 				}
18010 			}
18011 		}
18012 		/* Window scaling. */
18013 		if ((flags & TH_SYN) && (tp->t_flags & TF_REQ_SCALE)) {
18014 			to.to_wscale = tp->request_r_scale;
18015 			to.to_flags |= TOF_SCALE;
18016 		}
18017 		/* Timestamps. */
18018 		if ((tp->t_flags & TF_RCVD_TSTMP) ||
18019 		    ((flags & TH_SYN) && (tp->t_flags & TF_REQ_TSTMP))) {
18020 			to.to_tsval = ms_cts + tp->ts_offset;
18021 			to.to_tsecr = tp->ts_recent;
18022 			to.to_flags |= TOF_TS;
18023 		}
18024 		/* Set receive buffer autosizing timestamp. */
18025 		if (tp->rfbuf_ts == 0 &&
18026 		    (so->so_rcv.sb_flags & SB_AUTOSIZE))
18027 			tp->rfbuf_ts = tcp_ts_getticks();
18028 		/* Selective ACK's. */
18029 		if (tp->t_flags & TF_SACK_PERMIT) {
18030 			if (flags & TH_SYN)
18031 				to.to_flags |= TOF_SACKPERM;
18032 			else if (TCPS_HAVEESTABLISHED(tp->t_state) &&
18033 				 tp->rcv_numsacks > 0) {
18034 				to.to_flags |= TOF_SACK;
18035 				to.to_nsacks = tp->rcv_numsacks;
18036 				to.to_sacks = (u_char *)tp->sackblks;
18037 			}
18038 		}
18039 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
18040 		/* TCP-MD5 (RFC2385). */
18041 		if (tp->t_flags & TF_SIGNATURE)
18042 			to.to_flags |= TOF_SIGNATURE;
18043 #endif				/* TCP_SIGNATURE */
18044 
18045 		/* Processing the options. */
18046 		hdrlen += optlen = tcp_addoptions(&to, opt);
18047 		/*
18048 		 * If we wanted a TFO option to be added, but it was unable
18049 		 * to fit, ensure no data is sent.
18050 		 */
18051 		if (IS_FASTOPEN(tp->t_flags) && wanted_cookie &&
18052 		    !(to.to_flags & TOF_FASTOPEN))
18053 			len = 0;
18054 	}
18055 	if (tp->t_port) {
18056 		if (V_tcp_udp_tunneling_port == 0) {
18057 			/* The port was removed?? */
18058 			SOCKBUF_UNLOCK(&so->so_snd);
18059 #ifdef TCP_ACCOUNTING
18060 			crtsc = get_cyclecount();
18061 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
18062 				tp->tcp_cnt_counters[SND_OUT_FAIL]++;
18063 			}
18064 			counter_u64_add(tcp_cnt_counters[SND_OUT_FAIL], 1);
18065 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
18066 				tp->tcp_proc_time[SND_OUT_FAIL] += (crtsc - ts_val);
18067 			}
18068 			counter_u64_add(tcp_proc_time[SND_OUT_FAIL], (crtsc - ts_val));
18069 			sched_unpin();
18070 #endif
18071 			return (EHOSTUNREACH);
18072 		}
18073 		hdrlen += sizeof(struct udphdr);
18074 	}
18075 #ifdef INET6
18076 	if (isipv6)
18077 		ipoptlen = ip6_optlen(inp);
18078 	else
18079 #endif
18080 		if (inp->inp_options)
18081 			ipoptlen = inp->inp_options->m_len -
18082 				offsetof(struct ipoption, ipopt_list);
18083 		else
18084 			ipoptlen = 0;
18085 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
18086 	ipoptlen += ipsec_optlen;
18087 #endif
18088 
18089 	/*
18090 	 * Adjust data length if insertion of options will bump the packet
18091 	 * length beyond the t_maxseg length. Clear the FIN bit because we
18092 	 * cut off the tail of the segment.
18093 	 */
18094 	if (len + optlen + ipoptlen > tp->t_maxseg) {
18095 		if (tso) {
18096 			uint32_t if_hw_tsomax;
18097 			uint32_t moff;
18098 			int32_t max_len;
18099 
18100 			/* extract TSO information */
18101 			if_hw_tsomax = tp->t_tsomax;
18102 			if_hw_tsomaxsegcount = tp->t_tsomaxsegcount;
18103 			if_hw_tsomaxsegsize = tp->t_tsomaxsegsize;
18104 			KASSERT(ipoptlen == 0,
18105 				("%s: TSO can't do IP options", __func__));
18106 
18107 			/*
18108 			 * Check if we should limit by maximum payload
18109 			 * length:
18110 			 */
18111 			if (if_hw_tsomax != 0) {
18112 				/* compute maximum TSO length */
18113 				max_len = (if_hw_tsomax - hdrlen -
18114 					   max_linkhdr);
18115 				if (max_len <= 0) {
18116 					len = 0;
18117 				} else if (len > max_len) {
18118 					sendalot = 1;
18119 					len = max_len;
18120 					mark = 2;
18121 				}
18122 			}
18123 			/*
18124 			 * Prevent the last segment from being fractional
18125 			 * unless the send sockbuf can be emptied:
18126 			 */
18127 			max_len = (tp->t_maxseg - optlen);
18128 			if ((sb_offset + len) < sbavail(sb)) {
18129 				moff = len % (u_int)max_len;
18130 				if (moff != 0) {
18131 					mark = 3;
18132 					len -= moff;
18133 				}
18134 			}
18135 			/*
18136 			 * In case there are too many small fragments don't
18137 			 * use TSO:
18138 			 */
18139 			if (len <= segsiz) {
18140 				mark = 4;
18141 				tso = 0;
18142 			}
18143 			/*
18144 			 * Send the FIN in a separate segment after the bulk
18145 			 * sending is done. We don't trust the TSO
18146 			 * implementations to clear the FIN flag on all but
18147 			 * the last segment.
18148 			 */
18149 			if (tp->t_flags & TF_NEEDFIN) {
18150 				sendalot = 4;
18151 			}
18152 		} else {
18153 			mark = 5;
18154 			if (optlen + ipoptlen >= tp->t_maxseg) {
18155 				/*
18156 				 * Since we don't have enough space to put
18157 				 * the IP header chain and the TCP header in
18158 				 * one packet as required by RFC 7112, don't
18159 				 * send it. Also ensure that at least one
18160 				 * byte of the payload can be put into the
18161 				 * TCP segment.
18162 				 */
18163 				SOCKBUF_UNLOCK(&so->so_snd);
18164 				error = EMSGSIZE;
18165 				sack_rxmit = 0;
18166 				goto out;
18167 			}
18168 			len = tp->t_maxseg - optlen - ipoptlen;
18169 			sendalot = 5;
18170 		}
18171 	} else {
18172 		tso = 0;
18173 		mark = 6;
18174 	}
18175 	KASSERT(len + hdrlen + ipoptlen <= IP_MAXPACKET,
18176 		("%s: len > IP_MAXPACKET", __func__));
18177 #ifdef DIAGNOSTIC
18178 #ifdef INET6
18179 	if (max_linkhdr + hdrlen > MCLBYTES)
18180 #else
18181 		if (max_linkhdr + hdrlen > MHLEN)
18182 #endif
18183 			panic("tcphdr too big");
18184 #endif
18185 
18186 	/*
18187 	 * This KASSERT is here to catch edge cases at a well defined place.
18188 	 * Before, those had triggered (random) panic conditions further
18189 	 * down.
18190 	 */
18191 	KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__));
18192 	if ((len == 0) &&
18193 	    (flags & TH_FIN) &&
18194 	    (sbused(sb))) {
18195 		/*
18196 		 * We have outstanding data, don't send a fin by itself!.
18197 		 */
18198 		goto just_return;
18199 	}
18200 	/*
18201 	 * Grab a header mbuf, attaching a copy of data to be transmitted,
18202 	 * and initialize the header from the template for sends on this
18203 	 * connection.
18204 	 */
18205 	hw_tls = tp->t_nic_ktls_xmit != 0;
18206 	if (len) {
18207 		uint32_t max_val;
18208 		uint32_t moff;
18209 
18210 		if (rack->r_ctl.rc_pace_max_segs)
18211 			max_val = rack->r_ctl.rc_pace_max_segs;
18212 		else if (rack->rc_user_set_max_segs)
18213 			max_val = rack->rc_user_set_max_segs * segsiz;
18214 		else
18215 			max_val = len;
18216 		/*
18217 		 * We allow a limit on sending with hptsi.
18218 		 */
18219 		if (len > max_val) {
18220 			mark = 7;
18221 			len = max_val;
18222 		}
18223 #ifdef INET6
18224 		if (MHLEN < hdrlen + max_linkhdr)
18225 			m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
18226 		else
18227 #endif
18228 			m = m_gethdr(M_NOWAIT, MT_DATA);
18229 
18230 		if (m == NULL) {
18231 			SOCKBUF_UNLOCK(sb);
18232 			error = ENOBUFS;
18233 			sack_rxmit = 0;
18234 			goto out;
18235 		}
18236 		m->m_data += max_linkhdr;
18237 		m->m_len = hdrlen;
18238 
18239 		/*
18240 		 * Start the m_copy functions from the closest mbuf to the
18241 		 * sb_offset in the socket buffer chain.
18242 		 */
18243 		mb = sbsndptr_noadv(sb, sb_offset, &moff);
18244 		s_mb = mb;
18245 		s_moff = moff;
18246 		if (len <= MHLEN - hdrlen - max_linkhdr && !hw_tls) {
18247 			m_copydata(mb, moff, (int)len,
18248 				   mtod(m, caddr_t)+hdrlen);
18249 			if (SEQ_LT(tp->snd_nxt, tp->snd_max))
18250 				sbsndptr_adv(sb, mb, len);
18251 			m->m_len += len;
18252 		} else {
18253 			struct sockbuf *msb;
18254 
18255 			if (SEQ_LT(tp->snd_nxt, tp->snd_max))
18256 				msb = NULL;
18257 			else
18258 				msb = sb;
18259 			m->m_next = tcp_m_copym(
18260 				mb, moff, &len,
18261 				if_hw_tsomaxsegcount, if_hw_tsomaxsegsize, msb,
18262 				((rsm == NULL) ? hw_tls : 0)
18263 #ifdef NETFLIX_COPY_ARGS
18264 				, &s_mb, &s_moff
18265 #endif
18266 				);
18267 			if (len <= (tp->t_maxseg - optlen)) {
18268 				/*
18269 				 * Must have ran out of mbufs for the copy
18270 				 * shorten it to no longer need tso. Lets
18271 				 * not put on sendalot since we are low on
18272 				 * mbufs.
18273 				 */
18274 				tso = 0;
18275 			}
18276 			if (m->m_next == NULL) {
18277 				SOCKBUF_UNLOCK(sb);
18278 				(void)m_free(m);
18279 				error = ENOBUFS;
18280 				sack_rxmit = 0;
18281 				goto out;
18282 			}
18283 		}
18284 		if (SEQ_LT(tp->snd_nxt, tp->snd_max) || sack_rxmit) {
18285 			if (rsm && (rsm->r_flags & RACK_TLP)) {
18286 				/*
18287 				 * TLP should not count in retran count, but
18288 				 * in its own bin
18289 				 */
18290 				counter_u64_add(rack_tlp_retran, 1);
18291 				counter_u64_add(rack_tlp_retran_bytes, len);
18292 			} else {
18293 				tp->t_sndrexmitpack++;
18294 				KMOD_TCPSTAT_INC(tcps_sndrexmitpack);
18295 				KMOD_TCPSTAT_ADD(tcps_sndrexmitbyte, len);
18296 			}
18297 #ifdef STATS
18298 			stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RETXPB,
18299 						 len);
18300 #endif
18301 		} else {
18302 			KMOD_TCPSTAT_INC(tcps_sndpack);
18303 			KMOD_TCPSTAT_ADD(tcps_sndbyte, len);
18304 #ifdef STATS
18305 			stats_voi_update_abs_u64(tp->t_stats, VOI_TCP_TXPB,
18306 						 len);
18307 #endif
18308 		}
18309 		/*
18310 		 * If we're sending everything we've got, set PUSH. (This
18311 		 * will keep happy those implementations which only give
18312 		 * data to the user when a buffer fills or a PUSH comes in.)
18313 		 */
18314 		if (sb_offset + len == sbused(sb) &&
18315 		    sbused(sb) &&
18316 		    !(flags & TH_SYN)) {
18317 			flags |= TH_PUSH;
18318 			add_flag |= RACK_HAD_PUSH;
18319 		}
18320 
18321 		SOCKBUF_UNLOCK(sb);
18322 	} else {
18323 		SOCKBUF_UNLOCK(sb);
18324 		if (tp->t_flags & TF_ACKNOW)
18325 			KMOD_TCPSTAT_INC(tcps_sndacks);
18326 		else if (flags & (TH_SYN | TH_FIN | TH_RST))
18327 			KMOD_TCPSTAT_INC(tcps_sndctrl);
18328 		else
18329 			KMOD_TCPSTAT_INC(tcps_sndwinup);
18330 
18331 		m = m_gethdr(M_NOWAIT, MT_DATA);
18332 		if (m == NULL) {
18333 			error = ENOBUFS;
18334 			sack_rxmit = 0;
18335 			goto out;
18336 		}
18337 #ifdef INET6
18338 		if (isipv6 && (MHLEN < hdrlen + max_linkhdr) &&
18339 		    MHLEN >= hdrlen) {
18340 			M_ALIGN(m, hdrlen);
18341 		} else
18342 #endif
18343 			m->m_data += max_linkhdr;
18344 		m->m_len = hdrlen;
18345 	}
18346 	SOCKBUF_UNLOCK_ASSERT(sb);
18347 	m->m_pkthdr.rcvif = (struct ifnet *)0;
18348 #ifdef MAC
18349 	mac_inpcb_create_mbuf(inp, m);
18350 #endif
18351 	if ((ipoptlen == 0) && (rack->r_ctl.fsb.tcp_ip_hdr) &&  rack->r_fsb_inited) {
18352 #ifdef INET6
18353 		if (isipv6)
18354 			ip6 = (struct ip6_hdr *)rack->r_ctl.fsb.tcp_ip_hdr;
18355 		else
18356 #endif				/* INET6 */
18357 #ifdef INET
18358 			ip = (struct ip *)rack->r_ctl.fsb.tcp_ip_hdr;
18359 #endif
18360 		th = rack->r_ctl.fsb.th;
18361 		udp = rack->r_ctl.fsb.udp;
18362 		if (udp) {
18363 #ifdef INET6
18364 			if (isipv6)
18365 				ulen = hdrlen + len - sizeof(struct ip6_hdr);
18366 			else
18367 #endif				/* INET6 */
18368 				ulen = hdrlen + len - sizeof(struct ip);
18369 			udp->uh_ulen = htons(ulen);
18370 		}
18371 	} else {
18372 #ifdef INET6
18373 		if (isipv6) {
18374 			ip6 = mtod(m, struct ip6_hdr *);
18375 			if (tp->t_port) {
18376 				udp = (struct udphdr *)((caddr_t)ip6 + sizeof(struct ip6_hdr));
18377 				udp->uh_sport = htons(V_tcp_udp_tunneling_port);
18378 				udp->uh_dport = tp->t_port;
18379 				ulen = hdrlen + len - sizeof(struct ip6_hdr);
18380 				udp->uh_ulen = htons(ulen);
18381 				th = (struct tcphdr *)(udp + 1);
18382 			} else
18383 				th = (struct tcphdr *)(ip6 + 1);
18384 			tcpip_fillheaders(inp, tp->t_port, ip6, th);
18385 		} else
18386 #endif				/* INET6 */
18387 		{
18388 #ifdef INET
18389 			ip = mtod(m, struct ip *);
18390 			if (tp->t_port) {
18391 				udp = (struct udphdr *)((caddr_t)ip + sizeof(struct ip));
18392 				udp->uh_sport = htons(V_tcp_udp_tunneling_port);
18393 				udp->uh_dport = tp->t_port;
18394 				ulen = hdrlen + len - sizeof(struct ip);
18395 				udp->uh_ulen = htons(ulen);
18396 				th = (struct tcphdr *)(udp + 1);
18397 			} else
18398 				th = (struct tcphdr *)(ip + 1);
18399 			tcpip_fillheaders(inp, tp->t_port, ip, th);
18400 #endif
18401 		}
18402 	}
18403 	/*
18404 	 * Fill in fields, remembering maximum advertised window for use in
18405 	 * delaying messages about window sizes. If resending a FIN, be sure
18406 	 * not to use a new sequence number.
18407 	 */
18408 	if (flags & TH_FIN && tp->t_flags & TF_SENTFIN &&
18409 	    tp->snd_nxt == tp->snd_max)
18410 		tp->snd_nxt--;
18411 	/*
18412 	 * If we are starting a connection, send ECN setup SYN packet. If we
18413 	 * are on a retransmit, we may resend those bits a number of times
18414 	 * as per RFC 3168.
18415 	 */
18416 	if (tp->t_state == TCPS_SYN_SENT && V_tcp_do_ecn) {
18417 		flags |= tcp_ecn_output_syn_sent(tp);
18418 	}
18419 	/* Also handle parallel SYN for ECN */
18420 	if (TCPS_HAVERCVDSYN(tp->t_state) &&
18421 	    (tp->t_flags2 & (TF2_ECN_PERMIT | TF2_ACE_PERMIT))) {
18422 		int ect = tcp_ecn_output_established(tp, &flags, len, sack_rxmit);
18423 		if ((tp->t_state == TCPS_SYN_RECEIVED) &&
18424 		    (tp->t_flags2 & TF2_ECN_SND_ECE))
18425 			tp->t_flags2 &= ~TF2_ECN_SND_ECE;
18426 #ifdef INET6
18427 		if (isipv6) {
18428 			ip6->ip6_flow &= ~htonl(IPTOS_ECN_MASK << 20);
18429 			ip6->ip6_flow |= htonl(ect << 20);
18430 		}
18431 		else
18432 #endif
18433 		{
18434 #ifdef INET
18435 			ip->ip_tos &= ~IPTOS_ECN_MASK;
18436 			ip->ip_tos |= ect;
18437 #endif
18438 		}
18439 	}
18440 	/*
18441 	 * If we are doing retransmissions, then snd_nxt will not reflect
18442 	 * the first unsent octet.  For ACK only packets, we do not want the
18443 	 * sequence number of the retransmitted packet, we want the sequence
18444 	 * number of the next unsent octet.  So, if there is no data (and no
18445 	 * SYN or FIN), use snd_max instead of snd_nxt when filling in
18446 	 * ti_seq.  But if we are in persist state, snd_max might reflect
18447 	 * one byte beyond the right edge of the window, so use snd_nxt in
18448 	 * that case, since we know we aren't doing a retransmission.
18449 	 * (retransmit and persist are mutually exclusive...)
18450 	 */
18451 	if (sack_rxmit == 0) {
18452 		if (len || (flags & (TH_SYN | TH_FIN))) {
18453 			th->th_seq = htonl(tp->snd_nxt);
18454 			rack_seq = tp->snd_nxt;
18455 		} else {
18456 			th->th_seq = htonl(tp->snd_max);
18457 			rack_seq = tp->snd_max;
18458 		}
18459 	} else {
18460 		th->th_seq = htonl(rsm->r_start);
18461 		rack_seq = rsm->r_start;
18462 	}
18463 	th->th_ack = htonl(tp->rcv_nxt);
18464 	tcp_set_flags(th, flags);
18465 	/*
18466 	 * Calculate receive window.  Don't shrink window, but avoid silly
18467 	 * window syndrome.
18468 	 * If a RST segment is sent, advertise a window of zero.
18469 	 */
18470 	if (flags & TH_RST) {
18471 		recwin = 0;
18472 	} else {
18473 		if (recwin < (long)(so->so_rcv.sb_hiwat / 4) &&
18474 		    recwin < (long)segsiz) {
18475 			recwin = 0;
18476 		}
18477 		if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt) &&
18478 		    recwin < (long)(tp->rcv_adv - tp->rcv_nxt))
18479 			recwin = (long)(tp->rcv_adv - tp->rcv_nxt);
18480 	}
18481 
18482 	/*
18483 	 * According to RFC1323 the window field in a SYN (i.e., a <SYN> or
18484 	 * <SYN,ACK>) segment itself is never scaled.  The <SYN,ACK> case is
18485 	 * handled in syncache.
18486 	 */
18487 	if (flags & TH_SYN)
18488 		th->th_win = htons((u_short)
18489 				   (min(sbspace(&so->so_rcv), TCP_MAXWIN)));
18490 	else {
18491 		/* Avoid shrinking window with window scaling. */
18492 		recwin = roundup2(recwin, 1 << tp->rcv_scale);
18493 		th->th_win = htons((u_short)(recwin >> tp->rcv_scale));
18494 	}
18495 	/*
18496 	 * Adjust the RXWIN0SENT flag - indicate that we have advertised a 0
18497 	 * window.  This may cause the remote transmitter to stall.  This
18498 	 * flag tells soreceive() to disable delayed acknowledgements when
18499 	 * draining the buffer.  This can occur if the receiver is
18500 	 * attempting to read more data than can be buffered prior to
18501 	 * transmitting on the connection.
18502 	 */
18503 	if (th->th_win == 0) {
18504 		tp->t_sndzerowin++;
18505 		tp->t_flags |= TF_RXWIN0SENT;
18506 	} else
18507 		tp->t_flags &= ~TF_RXWIN0SENT;
18508 	tp->snd_up = tp->snd_una;	/* drag it along, its deprecated */
18509 	/* Now are we using fsb?, if so copy the template data to the mbuf */
18510 	if ((ipoptlen == 0) && (rack->r_ctl.fsb.tcp_ip_hdr) && rack->r_fsb_inited) {
18511 		uint8_t *cpto;
18512 
18513 		cpto = mtod(m, uint8_t *);
18514 		memcpy(cpto, rack->r_ctl.fsb.tcp_ip_hdr, rack->r_ctl.fsb.tcp_ip_hdr_len);
18515 		/*
18516 		 * We have just copied in:
18517 		 * IP/IP6
18518 		 * <optional udphdr>
18519 		 * tcphdr (no options)
18520 		 *
18521 		 * We need to grab the correct pointers into the mbuf
18522 		 * for both the tcp header, and possibly the udp header (if tunneling).
18523 		 * We do this by using the offset in the copy buffer and adding it
18524 		 * to the mbuf base pointer (cpto).
18525 		 */
18526 #ifdef INET6
18527 		if (isipv6)
18528 			ip6 = mtod(m, struct ip6_hdr *);
18529 		else
18530 #endif				/* INET6 */
18531 #ifdef INET
18532 			ip = mtod(m, struct ip *);
18533 #endif
18534 		th = (struct tcphdr *)(cpto + ((uint8_t *)rack->r_ctl.fsb.th - rack->r_ctl.fsb.tcp_ip_hdr));
18535 		/* If we have a udp header lets set it into the mbuf as well */
18536 		if (udp)
18537 			udp = (struct udphdr *)(cpto + ((uint8_t *)rack->r_ctl.fsb.udp - rack->r_ctl.fsb.tcp_ip_hdr));
18538 	}
18539 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
18540 	if (to.to_flags & TOF_SIGNATURE) {
18541 		/*
18542 		 * Calculate MD5 signature and put it into the place
18543 		 * determined before.
18544 		 * NOTE: since TCP options buffer doesn't point into
18545 		 * mbuf's data, calculate offset and use it.
18546 		 */
18547 		if (!TCPMD5_ENABLED() || TCPMD5_OUTPUT(m, th,
18548 						       (u_char *)(th + 1) + (to.to_signature - opt)) != 0) {
18549 			/*
18550 			 * Do not send segment if the calculation of MD5
18551 			 * digest has failed.
18552 			 */
18553 			goto out;
18554 		}
18555 	}
18556 #endif
18557 	if (optlen) {
18558 		bcopy(opt, th + 1, optlen);
18559 		th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
18560 	}
18561 	/*
18562 	 * Put TCP length in extended header, and then checksum extended
18563 	 * header and data.
18564 	 */
18565 	m->m_pkthdr.len = hdrlen + len;	/* in6_cksum() need this */
18566 #ifdef INET6
18567 	if (isipv6) {
18568 		/*
18569 		 * ip6_plen is not need to be filled now, and will be filled
18570 		 * in ip6_output.
18571 		 */
18572 		if (tp->t_port) {
18573 			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
18574 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
18575 			udp->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0);
18576 			th->th_sum = htons(0);
18577 			UDPSTAT_INC(udps_opackets);
18578 		} else {
18579 			m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
18580 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
18581 			th->th_sum = in6_cksum_pseudo(ip6,
18582 						      sizeof(struct tcphdr) + optlen + len, IPPROTO_TCP,
18583 						      0);
18584 		}
18585 	}
18586 #endif
18587 #if defined(INET6) && defined(INET)
18588 	else
18589 #endif
18590 #ifdef INET
18591 	{
18592 		if (tp->t_port) {
18593 			m->m_pkthdr.csum_flags = CSUM_UDP;
18594 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
18595 			udp->uh_sum = in_pseudo(ip->ip_src.s_addr,
18596 						ip->ip_dst.s_addr, htons(ulen + IPPROTO_UDP));
18597 			th->th_sum = htons(0);
18598 			UDPSTAT_INC(udps_opackets);
18599 		} else {
18600 			m->m_pkthdr.csum_flags = CSUM_TCP;
18601 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
18602 			th->th_sum = in_pseudo(ip->ip_src.s_addr,
18603 					       ip->ip_dst.s_addr, htons(sizeof(struct tcphdr) +
18604 									IPPROTO_TCP + len + optlen));
18605 		}
18606 		/* IP version must be set here for ipv4/ipv6 checking later */
18607 		KASSERT(ip->ip_v == IPVERSION,
18608 			("%s: IP version incorrect: %d", __func__, ip->ip_v));
18609 	}
18610 #endif
18611 	/*
18612 	 * Enable TSO and specify the size of the segments. The TCP pseudo
18613 	 * header checksum is always provided. XXX: Fixme: This is currently
18614 	 * not the case for IPv6.
18615 	 */
18616 	if (tso) {
18617 		KASSERT(len > tp->t_maxseg - optlen,
18618 			("%s: len <= tso_segsz", __func__));
18619 		m->m_pkthdr.csum_flags |= CSUM_TSO;
18620 		m->m_pkthdr.tso_segsz = tp->t_maxseg - optlen;
18621 	}
18622 	KASSERT(len + hdrlen == m_length(m, NULL),
18623 		("%s: mbuf chain different than expected: %d + %u != %u",
18624 		 __func__, len, hdrlen, m_length(m, NULL)));
18625 
18626 #ifdef TCP_HHOOK
18627 	/* Run HHOOK_TCP_ESTABLISHED_OUT helper hooks. */
18628 	hhook_run_tcp_est_out(tp, th, &to, len, tso);
18629 #endif
18630 	/* We're getting ready to send; log now. */
18631 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
18632 		union tcp_log_stackspecific log;
18633 
18634 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
18635 		log.u_bbr.inhpts = tcp_in_hpts(rack->rc_inp);
18636 		if (rack->rack_no_prr)
18637 			log.u_bbr.flex1 = 0;
18638 		else
18639 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
18640 		log.u_bbr.flex2 = rack->r_ctl.rc_pace_min_segs;
18641 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_max_segs;
18642 		log.u_bbr.flex4 = orig_len;
18643 		/* Save off the early/late values */
18644 		log.u_bbr.flex6 = rack->r_ctl.rc_agg_early;
18645 		log.u_bbr.applimited = rack->r_ctl.rc_agg_delayed;
18646 		log.u_bbr.bw_inuse = rack_get_bw(rack);
18647 		log.u_bbr.flex8 = 0;
18648 		if (rsm) {
18649 			if (rsm->r_flags & RACK_RWND_COLLAPSED) {
18650 				rack_log_collapse(rack, rsm->r_start, rsm->r_end, 0, __LINE__, 5, rsm->r_flags, rsm);
18651 				counter_u64_add(rack_collapsed_win_rxt, 1);
18652 				counter_u64_add(rack_collapsed_win_rxt_bytes, (rsm->r_end - rsm->r_start));
18653 			}
18654 			if (doing_tlp)
18655 				log.u_bbr.flex8 = 2;
18656 			else
18657 				log.u_bbr.flex8 = 1;
18658 		} else {
18659 			if (doing_tlp)
18660 				log.u_bbr.flex8 = 3;
18661 			else
18662 				log.u_bbr.flex8 = 0;
18663 		}
18664 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, rsm);
18665 		log.u_bbr.flex7 = mark;
18666 		log.u_bbr.flex7 <<= 8;
18667 		log.u_bbr.flex7 |= pass;
18668 		log.u_bbr.pkts_out = tp->t_maxseg;
18669 		log.u_bbr.timeStamp = cts;
18670 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
18671 		log.u_bbr.lt_epoch = cwnd_to_use;
18672 		log.u_bbr.delivered = sendalot;
18673 		lgb = tcp_log_event_(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_OUT, ERRNO_UNK,
18674 				     len, &log, false, NULL, NULL, 0, &tv);
18675 	} else
18676 		lgb = NULL;
18677 
18678 	/*
18679 	 * Fill in IP length and desired time to live and send to IP level.
18680 	 * There should be a better way to handle ttl and tos; we could keep
18681 	 * them in the template, but need a way to checksum without them.
18682 	 */
18683 	/*
18684 	 * m->m_pkthdr.len should have been set before cksum calcuration,
18685 	 * because in6_cksum() need it.
18686 	 */
18687 #ifdef INET6
18688 	if (isipv6) {
18689 		/*
18690 		 * we separately set hoplimit for every segment, since the
18691 		 * user might want to change the value via setsockopt. Also,
18692 		 * desired default hop limit might be changed via Neighbor
18693 		 * Discovery.
18694 		 */
18695 		rack->r_ctl.fsb.hoplimit = ip6->ip6_hlim = in6_selecthlim(inp, NULL);
18696 
18697 		/*
18698 		 * Set the packet size here for the benefit of DTrace
18699 		 * probes. ip6_output() will set it properly; it's supposed
18700 		 * to include the option header lengths as well.
18701 		 */
18702 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
18703 
18704 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss)
18705 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
18706 		else
18707 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
18708 
18709 		if (tp->t_state == TCPS_SYN_SENT)
18710 			TCP_PROBE5(connect__request, NULL, tp, ip6, tp, th);
18711 
18712 		TCP_PROBE5(send, NULL, tp, ip6, tp, th);
18713 		/* TODO: IPv6 IP6TOS_ECT bit on */
18714 		error = ip6_output(m,
18715 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
18716 				   inp->in6p_outputopts,
18717 #else
18718 				   NULL,
18719 #endif
18720 				   &inp->inp_route6,
18721 				   ((rsm || sack_rxmit) ? IP_NO_SND_TAG_RL : 0),
18722 				   NULL, NULL, inp);
18723 
18724 		if (error == EMSGSIZE && inp->inp_route6.ro_nh != NULL)
18725 			mtu = inp->inp_route6.ro_nh->nh_mtu;
18726 	}
18727 #endif				/* INET6 */
18728 #if defined(INET) && defined(INET6)
18729 	else
18730 #endif
18731 #ifdef INET
18732 	{
18733 		ip->ip_len = htons(m->m_pkthdr.len);
18734 #ifdef INET6
18735 		if (inp->inp_vflag & INP_IPV6PROTO)
18736 			ip->ip_ttl = in6_selecthlim(inp, NULL);
18737 #endif				/* INET6 */
18738 		rack->r_ctl.fsb.hoplimit = ip->ip_ttl;
18739 		/*
18740 		 * If we do path MTU discovery, then we set DF on every
18741 		 * packet. This might not be the best thing to do according
18742 		 * to RFC3390 Section 2. However the tcp hostcache migitates
18743 		 * the problem so it affects only the first tcp connection
18744 		 * with a host.
18745 		 *
18746 		 * NB: Don't set DF on small MTU/MSS to have a safe
18747 		 * fallback.
18748 		 */
18749 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) {
18750 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
18751 			if (tp->t_port == 0 || len < V_tcp_minmss) {
18752 				ip->ip_off |= htons(IP_DF);
18753 			}
18754 		} else {
18755 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
18756 		}
18757 
18758 		if (tp->t_state == TCPS_SYN_SENT)
18759 			TCP_PROBE5(connect__request, NULL, tp, ip, tp, th);
18760 
18761 		TCP_PROBE5(send, NULL, tp, ip, tp, th);
18762 
18763 		error = ip_output(m,
18764 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
18765 				  inp->inp_options,
18766 #else
18767 				  NULL,
18768 #endif
18769 				  &inp->inp_route,
18770 				  ((rsm || sack_rxmit) ? IP_NO_SND_TAG_RL : 0), 0,
18771 				  inp);
18772 		if (error == EMSGSIZE && inp->inp_route.ro_nh != NULL)
18773 			mtu = inp->inp_route.ro_nh->nh_mtu;
18774 	}
18775 #endif				/* INET */
18776 
18777 out:
18778 	if (lgb) {
18779 		lgb->tlb_errno = error;
18780 		lgb = NULL;
18781 	}
18782 	/*
18783 	 * In transmit state, time the transmission and arrange for the
18784 	 * retransmit.  In persist state, just set snd_max.
18785 	 */
18786 	if (error == 0) {
18787 		tcp_account_for_send(tp, len, (rsm != NULL), doing_tlp, hw_tls);
18788 		if (rsm && doing_tlp) {
18789 			rack->rc_last_sent_tlp_past_cumack = 0;
18790 			rack->rc_last_sent_tlp_seq_valid = 1;
18791 			rack->r_ctl.last_sent_tlp_seq = rsm->r_start;
18792 			rack->r_ctl.last_sent_tlp_len = rsm->r_end - rsm->r_start;
18793 		}
18794 		rack->forced_ack = 0;	/* If we send something zap the FA flag */
18795 		if (rsm && (doing_tlp == 0)) {
18796 			/* Set we retransmitted */
18797 			rack->rc_gp_saw_rec = 1;
18798 		} else {
18799 			if (cwnd_to_use > tp->snd_ssthresh) {
18800 				/* Set we sent in CA */
18801 				rack->rc_gp_saw_ca = 1;
18802 			} else {
18803 				/* Set we sent in SS */
18804 				rack->rc_gp_saw_ss = 1;
18805 			}
18806 		}
18807 		if (TCPS_HAVEESTABLISHED(tp->t_state) &&
18808 		    (tp->t_flags & TF_SACK_PERMIT) &&
18809 		    tp->rcv_numsacks > 0)
18810 			tcp_clean_dsack_blocks(tp);
18811 		tot_len_this_send += len;
18812 		if (len == 0)
18813 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_SNDACK], 1);
18814 		else if (len == 1) {
18815 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_PERSIST], 1);
18816 		} else if (len > 1) {
18817 			int idx;
18818 
18819 			idx = (len / segsiz) + 3;
18820 			if (idx >= TCP_MSS_ACCT_ATIMER)
18821 				counter_u64_add(rack_out_size[(TCP_MSS_ACCT_ATIMER-1)], 1);
18822 			else
18823 				counter_u64_add(rack_out_size[idx], 1);
18824 		}
18825 	}
18826 	if ((rack->rack_no_prr == 0) &&
18827 	    sub_from_prr &&
18828 	    (error == 0)) {
18829 		if (rack->r_ctl.rc_prr_sndcnt >= len)
18830 			rack->r_ctl.rc_prr_sndcnt -= len;
18831 		else
18832 			rack->r_ctl.rc_prr_sndcnt = 0;
18833 	}
18834 	sub_from_prr = 0;
18835 	if (doing_tlp) {
18836 		/* Make sure the TLP is added */
18837 		add_flag |= RACK_TLP;
18838 	} else if (rsm) {
18839 		/* If its a resend without TLP then it must not have the flag */
18840 		rsm->r_flags &= ~RACK_TLP;
18841 	}
18842 	rack_log_output(tp, &to, len, rack_seq, (uint8_t) flags, error,
18843 			rack_to_usec_ts(&tv),
18844 			rsm, add_flag, s_mb, s_moff, hw_tls);
18845 
18846 
18847 	if ((error == 0) &&
18848 	    (len > 0) &&
18849 	    (tp->snd_una == tp->snd_max))
18850 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
18851 	{
18852 		tcp_seq startseq = tp->snd_nxt;
18853 
18854 		/* Track our lost count */
18855 		if (rsm && (doing_tlp == 0))
18856 			rack->r_ctl.rc_loss_count += rsm->r_end - rsm->r_start;
18857 		/*
18858 		 * Advance snd_nxt over sequence space of this segment.
18859 		 */
18860 		if (error)
18861 			/* We don't log or do anything with errors */
18862 			goto nomore;
18863 		if (doing_tlp == 0) {
18864 			if (rsm == NULL) {
18865 				/*
18866 				 * Not a retransmission of some
18867 				 * sort, new data is going out so
18868 				 * clear our TLP count and flag.
18869 				 */
18870 				rack->rc_tlp_in_progress = 0;
18871 				rack->r_ctl.rc_tlp_cnt_out = 0;
18872 			}
18873 		} else {
18874 			/*
18875 			 * We have just sent a TLP, mark that it is true
18876 			 * and make sure our in progress is set so we
18877 			 * continue to check the count.
18878 			 */
18879 			rack->rc_tlp_in_progress = 1;
18880 			rack->r_ctl.rc_tlp_cnt_out++;
18881 		}
18882 		if (flags & (TH_SYN | TH_FIN)) {
18883 			if (flags & TH_SYN)
18884 				tp->snd_nxt++;
18885 			if (flags & TH_FIN) {
18886 				tp->snd_nxt++;
18887 				tp->t_flags |= TF_SENTFIN;
18888 			}
18889 		}
18890 		/* In the ENOBUFS case we do *not* update snd_max */
18891 		if (sack_rxmit)
18892 			goto nomore;
18893 
18894 		tp->snd_nxt += len;
18895 		if (SEQ_GT(tp->snd_nxt, tp->snd_max)) {
18896 			if (tp->snd_una == tp->snd_max) {
18897 				/*
18898 				 * Update the time we just added data since
18899 				 * none was outstanding.
18900 				 */
18901 				rack_log_progress_event(rack, tp, ticks, PROGRESS_START, __LINE__);
18902 				tp->t_acktime = ticks;
18903 			}
18904 			tp->snd_max = tp->snd_nxt;
18905 			/*
18906 			 * Time this transmission if not a retransmission and
18907 			 * not currently timing anything.
18908 			 * This is only relevant in case of switching back to
18909 			 * the base stack.
18910 			 */
18911 			if (tp->t_rtttime == 0) {
18912 				tp->t_rtttime = ticks;
18913 				tp->t_rtseq = startseq;
18914 				KMOD_TCPSTAT_INC(tcps_segstimed);
18915 			}
18916 			if (len &&
18917 			    ((tp->t_flags & TF_GPUTINPROG) == 0))
18918 				rack_start_gp_measurement(tp, rack, startseq, sb_offset);
18919 		}
18920 		/*
18921 		 * If we are doing FO we need to update the mbuf position and subtract
18922 		 * this happens when the peer sends us duplicate information and
18923 		 * we thus want to send a DSACK.
18924 		 *
18925 		 * XXXRRS: This brings to mind a ?, when we send a DSACK block is TSO
18926 		 * turned off? If not then we are going to echo multiple DSACK blocks
18927 		 * out (with the TSO), which we should not be doing.
18928 		 */
18929 		if (rack->r_fast_output && len) {
18930 			if (rack->r_ctl.fsb.left_to_send > len)
18931 				rack->r_ctl.fsb.left_to_send -= len;
18932 			else
18933 				rack->r_ctl.fsb.left_to_send = 0;
18934 			if (rack->r_ctl.fsb.left_to_send < segsiz)
18935 				rack->r_fast_output = 0;
18936 			if (rack->r_fast_output) {
18937 				rack->r_ctl.fsb.m = sbsndmbuf(sb, (tp->snd_max - tp->snd_una), &rack->r_ctl.fsb.off);
18938 				rack->r_ctl.fsb.o_m_len = rack->r_ctl.fsb.m->m_len;
18939 			}
18940 		}
18941 	}
18942 nomore:
18943 	if (error) {
18944 		rack->r_ctl.rc_agg_delayed = 0;
18945 		rack->r_early = 0;
18946 		rack->r_late = 0;
18947 		rack->r_ctl.rc_agg_early = 0;
18948 		SOCKBUF_UNLOCK_ASSERT(sb);	/* Check gotos. */
18949 		/*
18950 		 * Failures do not advance the seq counter above. For the
18951 		 * case of ENOBUFS we will fall out and retry in 1ms with
18952 		 * the hpts. Everything else will just have to retransmit
18953 		 * with the timer.
18954 		 *
18955 		 * In any case, we do not want to loop around for another
18956 		 * send without a good reason.
18957 		 */
18958 		sendalot = 0;
18959 		switch (error) {
18960 		case EPERM:
18961 			tp->t_softerror = error;
18962 #ifdef TCP_ACCOUNTING
18963 			crtsc = get_cyclecount();
18964 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
18965 				tp->tcp_cnt_counters[SND_OUT_FAIL]++;
18966 			}
18967 			counter_u64_add(tcp_cnt_counters[SND_OUT_FAIL], 1);
18968 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
18969 				tp->tcp_proc_time[SND_OUT_FAIL] += (crtsc - ts_val);
18970 			}
18971 			counter_u64_add(tcp_proc_time[SND_OUT_FAIL], (crtsc - ts_val));
18972 			sched_unpin();
18973 #endif
18974 			return (error);
18975 		case ENOBUFS:
18976 			/*
18977 			 * Pace us right away to retry in a some
18978 			 * time
18979 			 */
18980 			if (rack->r_ctl.crte != NULL) {
18981 				rack_trace_point(rack, RACK_TP_HWENOBUF);
18982 			} else
18983 				rack_trace_point(rack, RACK_TP_ENOBUF);
18984 			slot = ((1 + rack->rc_enobuf) * HPTS_USEC_IN_MSEC);
18985 			if (rack->rc_enobuf < 0x7f)
18986 				rack->rc_enobuf++;
18987 			if (slot < (10 * HPTS_USEC_IN_MSEC))
18988 				slot = 10 * HPTS_USEC_IN_MSEC;
18989 			if (rack->r_ctl.crte != NULL) {
18990 				counter_u64_add(rack_saw_enobuf_hw, 1);
18991 				tcp_rl_log_enobuf(rack->r_ctl.crte);
18992 			}
18993 			counter_u64_add(rack_saw_enobuf, 1);
18994 			goto enobufs;
18995 		case EMSGSIZE:
18996 			/*
18997 			 * For some reason the interface we used initially
18998 			 * to send segments changed to another or lowered
18999 			 * its MTU. If TSO was active we either got an
19000 			 * interface without TSO capabilits or TSO was
19001 			 * turned off. If we obtained mtu from ip_output()
19002 			 * then update it and try again.
19003 			 */
19004 			if (tso)
19005 				tp->t_flags &= ~TF_TSO;
19006 			if (mtu != 0) {
19007 				tcp_mss_update(tp, -1, mtu, NULL, NULL);
19008 				goto again;
19009 			}
19010 			slot = 10 * HPTS_USEC_IN_MSEC;
19011 			rack_start_hpts_timer(rack, tp, cts, slot, 0, 0);
19012 #ifdef TCP_ACCOUNTING
19013 			crtsc = get_cyclecount();
19014 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19015 				tp->tcp_cnt_counters[SND_OUT_FAIL]++;
19016 			}
19017 			counter_u64_add(tcp_cnt_counters[SND_OUT_FAIL], 1);
19018 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19019 				tp->tcp_proc_time[SND_OUT_FAIL] += (crtsc - ts_val);
19020 			}
19021 			counter_u64_add(tcp_proc_time[SND_OUT_FAIL], (crtsc - ts_val));
19022 			sched_unpin();
19023 #endif
19024 			return (error);
19025 		case ENETUNREACH:
19026 			counter_u64_add(rack_saw_enetunreach, 1);
19027 		case EHOSTDOWN:
19028 		case EHOSTUNREACH:
19029 		case ENETDOWN:
19030 			if (TCPS_HAVERCVDSYN(tp->t_state)) {
19031 				tp->t_softerror = error;
19032 			}
19033 			/* FALLTHROUGH */
19034 		default:
19035 			slot = 10 * HPTS_USEC_IN_MSEC;
19036 			rack_start_hpts_timer(rack, tp, cts, slot, 0, 0);
19037 #ifdef TCP_ACCOUNTING
19038 			crtsc = get_cyclecount();
19039 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19040 				tp->tcp_cnt_counters[SND_OUT_FAIL]++;
19041 			}
19042 			counter_u64_add(tcp_cnt_counters[SND_OUT_FAIL], 1);
19043 			if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19044 				tp->tcp_proc_time[SND_OUT_FAIL] += (crtsc - ts_val);
19045 			}
19046 			counter_u64_add(tcp_proc_time[SND_OUT_FAIL], (crtsc - ts_val));
19047 			sched_unpin();
19048 #endif
19049 			return (error);
19050 		}
19051 	} else {
19052 		rack->rc_enobuf = 0;
19053 		if (IN_FASTRECOVERY(tp->t_flags) && rsm)
19054 			rack->r_ctl.retran_during_recovery += len;
19055 	}
19056 	KMOD_TCPSTAT_INC(tcps_sndtotal);
19057 
19058 	/*
19059 	 * Data sent (as far as we can tell). If this advertises a larger
19060 	 * window than any other segment, then remember the size of the
19061 	 * advertised window. Any pending ACK has now been sent.
19062 	 */
19063 	if (recwin > 0 && SEQ_GT(tp->rcv_nxt + recwin, tp->rcv_adv))
19064 		tp->rcv_adv = tp->rcv_nxt + recwin;
19065 
19066 	tp->last_ack_sent = tp->rcv_nxt;
19067 	tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
19068 enobufs:
19069 	if (sendalot) {
19070 		/* Do we need to turn off sendalot? */
19071 		if (rack->r_ctl.rc_pace_max_segs &&
19072 		    (tot_len_this_send >= rack->r_ctl.rc_pace_max_segs)) {
19073 			/* We hit our max. */
19074 			sendalot = 0;
19075 		} else if ((rack->rc_user_set_max_segs) &&
19076 			   (tot_len_this_send >= (rack->rc_user_set_max_segs * segsiz))) {
19077 			/* We hit the user defined max */
19078 			sendalot = 0;
19079 		}
19080 	}
19081 	if ((error == 0) && (flags & TH_FIN))
19082 		tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_FIN);
19083 	if (flags & TH_RST) {
19084 		/*
19085 		 * We don't send again after sending a RST.
19086 		 */
19087 		slot = 0;
19088 		sendalot = 0;
19089 		if (error == 0)
19090 			tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
19091 	} else if ((slot == 0) && (sendalot == 0) && tot_len_this_send) {
19092 		/*
19093 		 * Get our pacing rate, if an error
19094 		 * occurred in sending (ENOBUF) we would
19095 		 * hit the else if with slot preset. Other
19096 		 * errors return.
19097 		 */
19098 		slot = rack_get_pacing_delay(rack, tp, tot_len_this_send, rsm, segsiz);
19099 	}
19100 	if (rsm &&
19101 	    (rsm->r_flags & RACK_HAS_SYN) == 0 &&
19102 	    rack->use_rack_rr) {
19103 		/* Its a retransmit and we use the rack cheat? */
19104 		if ((slot == 0) ||
19105 		    (rack->rc_always_pace == 0) ||
19106 		    (rack->r_rr_config == 1)) {
19107 			/*
19108 			 * We have no pacing set or we
19109 			 * are using old-style rack or
19110 			 * we are overridden to use the old 1ms pacing.
19111 			 */
19112 			slot = rack->r_ctl.rc_min_to;
19113 		}
19114 	}
19115 	/* We have sent clear the flag */
19116 	rack->r_ent_rec_ns = 0;
19117 	if (rack->r_must_retran) {
19118 		if (rsm) {
19119 			rack->r_ctl.rc_out_at_rto -= (rsm->r_end - rsm->r_start);
19120 			if (SEQ_GEQ(rsm->r_end, rack->r_ctl.rc_snd_max_at_rto)) {
19121 				/*
19122 				 * We have retransmitted all.
19123 				 */
19124 				rack->r_must_retran = 0;
19125 				rack->r_ctl.rc_out_at_rto = 0;
19126 			}
19127 		} else if (SEQ_GEQ(tp->snd_max, rack->r_ctl.rc_snd_max_at_rto)) {
19128 			/*
19129 			 * Sending new data will also kill
19130 			 * the loop.
19131 			 */
19132 			rack->r_must_retran = 0;
19133 			rack->r_ctl.rc_out_at_rto = 0;
19134 		}
19135 	}
19136 	rack->r_ctl.fsb.recwin = recwin;
19137 	if ((tp->t_flags & (TF_WASCRECOVERY|TF_WASFRECOVERY)) &&
19138 	    SEQ_GT(tp->snd_max, rack->r_ctl.rc_snd_max_at_rto)) {
19139 		/*
19140 		 * We hit an RTO and now have past snd_max at the RTO
19141 		 * clear all the WAS flags.
19142 		 */
19143 		tp->t_flags &= ~(TF_WASCRECOVERY|TF_WASFRECOVERY);
19144 	}
19145 	if (slot) {
19146 		/* set the rack tcb into the slot N */
19147 		if ((error == 0) &&
19148 		    rack_use_rfo &&
19149 		    ((flags & (TH_SYN|TH_FIN)) == 0) &&
19150 		    (rsm == NULL) &&
19151 		    (tp->snd_nxt == tp->snd_max) &&
19152 		    (ipoptlen == 0) &&
19153 		    (tp->rcv_numsacks == 0) &&
19154 		    rack->r_fsb_inited &&
19155 		    TCPS_HAVEESTABLISHED(tp->t_state) &&
19156 		    (rack->r_must_retran == 0) &&
19157 		    ((tp->t_flags & TF_NEEDFIN) == 0) &&
19158 		    (len > 0) && (orig_len > 0) &&
19159 		    (orig_len > len) &&
19160 		    ((orig_len - len) >= segsiz) &&
19161 		    ((optlen == 0) ||
19162 		     ((optlen == TCPOLEN_TSTAMP_APPA) && (to.to_flags & TOF_TS)))) {
19163 			/* We can send at least one more MSS using our fsb */
19164 
19165 			rack->r_fast_output = 1;
19166 			rack->r_ctl.fsb.m = sbsndmbuf(sb, (tp->snd_max - tp->snd_una), &rack->r_ctl.fsb.off);
19167 			rack->r_ctl.fsb.o_m_len = rack->r_ctl.fsb.m->m_len;
19168 			rack->r_ctl.fsb.tcp_flags = flags;
19169 			rack->r_ctl.fsb.left_to_send = orig_len - len;
19170 			if (hw_tls)
19171 				rack->r_ctl.fsb.hw_tls = 1;
19172 			else
19173 				rack->r_ctl.fsb.hw_tls = 0;
19174 			KASSERT((rack->r_ctl.fsb.left_to_send <= (sbavail(sb) - (tp->snd_max - tp->snd_una))),
19175 				("rack:%p left_to_send:%u sbavail:%u out:%u",
19176 				 rack, rack->r_ctl.fsb.left_to_send, sbavail(sb),
19177 				 (tp->snd_max - tp->snd_una)));
19178 			if (rack->r_ctl.fsb.left_to_send < segsiz)
19179 				rack->r_fast_output = 0;
19180 			else {
19181 				if (rack->r_ctl.fsb.left_to_send == (sbavail(sb) - (tp->snd_max - tp->snd_una)))
19182 					rack->r_ctl.fsb.rfo_apply_push = 1;
19183 				else
19184 					rack->r_ctl.fsb.rfo_apply_push = 0;
19185 			}
19186 		} else
19187 			rack->r_fast_output = 0;
19188 		rack_log_fsb(rack, tp, so, flags,
19189 			     ipoptlen, orig_len, len, error,
19190 			     (rsm == NULL), optlen, __LINE__, 2);
19191 	} else if (sendalot) {
19192 		int ret;
19193 
19194 		sack_rxmit = 0;
19195 		if ((error == 0) &&
19196 		    rack_use_rfo &&
19197 		    ((flags & (TH_SYN|TH_FIN)) == 0) &&
19198 		    (rsm == NULL) &&
19199 		    (ipoptlen == 0) &&
19200 		    (tp->rcv_numsacks == 0) &&
19201 		    (tp->snd_nxt == tp->snd_max) &&
19202 		    (rack->r_must_retran == 0) &&
19203 		    rack->r_fsb_inited &&
19204 		    TCPS_HAVEESTABLISHED(tp->t_state) &&
19205 		    ((tp->t_flags & TF_NEEDFIN) == 0) &&
19206 		    (len > 0) && (orig_len > 0) &&
19207 		    (orig_len > len) &&
19208 		    ((orig_len - len) >= segsiz) &&
19209 		    ((optlen == 0) ||
19210 		     ((optlen == TCPOLEN_TSTAMP_APPA) && (to.to_flags & TOF_TS)))) {
19211 			/* we can use fast_output for more */
19212 
19213 			rack->r_fast_output = 1;
19214 			rack->r_ctl.fsb.m = sbsndmbuf(sb, (tp->snd_max - tp->snd_una), &rack->r_ctl.fsb.off);
19215 			rack->r_ctl.fsb.o_m_len = rack->r_ctl.fsb.m->m_len;
19216 			rack->r_ctl.fsb.tcp_flags = flags;
19217 			rack->r_ctl.fsb.left_to_send = orig_len - len;
19218 			if (hw_tls)
19219 				rack->r_ctl.fsb.hw_tls = 1;
19220 			else
19221 				rack->r_ctl.fsb.hw_tls = 0;
19222 			KASSERT((rack->r_ctl.fsb.left_to_send <= (sbavail(sb) - (tp->snd_max - tp->snd_una))),
19223 				("rack:%p left_to_send:%u sbavail:%u out:%u",
19224 				 rack, rack->r_ctl.fsb.left_to_send, sbavail(sb),
19225 				 (tp->snd_max - tp->snd_una)));
19226 			if (rack->r_ctl.fsb.left_to_send < segsiz) {
19227 				rack->r_fast_output = 0;
19228 			}
19229 			if (rack->r_fast_output) {
19230 				if (rack->r_ctl.fsb.left_to_send == (sbavail(sb) - (tp->snd_max - tp->snd_una)))
19231 					rack->r_ctl.fsb.rfo_apply_push = 1;
19232 				else
19233 					rack->r_ctl.fsb.rfo_apply_push = 0;
19234 				rack_log_fsb(rack, tp, so, flags,
19235 					     ipoptlen, orig_len, len, error,
19236 					     (rsm == NULL), optlen, __LINE__, 3);
19237 				error = 0;
19238 				ret = rack_fast_output(tp, rack, ts_val, cts, ms_cts, &tv, tot_len_this_send, &error);
19239 				if (ret >= 0)
19240 					return (ret);
19241 			        else if (error)
19242 					goto nomore;
19243 
19244 			}
19245 		}
19246 		goto again;
19247 	}
19248 	/* Assure when we leave that snd_nxt will point to top */
19249 	if (SEQ_GT(tp->snd_max, tp->snd_nxt))
19250 		tp->snd_nxt = tp->snd_max;
19251 	rack_start_hpts_timer(rack, tp, cts, slot, tot_len_this_send, 0);
19252 #ifdef TCP_ACCOUNTING
19253 	crtsc = get_cyclecount() - ts_val;
19254 	if (tot_len_this_send) {
19255 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19256 			tp->tcp_cnt_counters[SND_OUT_DATA]++;
19257 		}
19258 		counter_u64_add(tcp_cnt_counters[SND_OUT_DATA], 1);
19259 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19260 			tp->tcp_proc_time[SND_OUT_DATA] += crtsc;
19261 		}
19262 		counter_u64_add(tcp_proc_time[SND_OUT_DATA], crtsc);
19263 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19264 			tp->tcp_cnt_counters[CNT_OF_MSS_OUT] += ((tot_len_this_send + segsiz - 1) /segsiz);
19265 		}
19266 		counter_u64_add(tcp_cnt_counters[CNT_OF_MSS_OUT], ((tot_len_this_send + segsiz - 1) /segsiz));
19267 	} else {
19268 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19269 			tp->tcp_cnt_counters[SND_OUT_ACK]++;
19270 		}
19271 		counter_u64_add(tcp_cnt_counters[SND_OUT_ACK], 1);
19272 		if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
19273 			tp->tcp_proc_time[SND_OUT_ACK] += crtsc;
19274 		}
19275 		counter_u64_add(tcp_proc_time[SND_OUT_ACK], crtsc);
19276 	}
19277 	sched_unpin();
19278 #endif
19279 	if (error == ENOBUFS)
19280 		error = 0;
19281 	return (error);
19282 }
19283 
19284 static void
19285 rack_update_seg(struct tcp_rack *rack)
19286 {
19287 	uint32_t orig_val;
19288 
19289 	orig_val = rack->r_ctl.rc_pace_max_segs;
19290 	rack_set_pace_segments(rack->rc_tp, rack, __LINE__, NULL);
19291 	if (orig_val != rack->r_ctl.rc_pace_max_segs)
19292 		rack_log_pacing_delay_calc(rack, 0, 0, orig_val, 0, 0, 15, __LINE__, NULL, 0);
19293 }
19294 
19295 static void
19296 rack_mtu_change(struct tcpcb *tp)
19297 {
19298 	/*
19299 	 * The MSS may have changed
19300 	 */
19301 	struct tcp_rack *rack;
19302 	struct rack_sendmap *rsm;
19303 
19304 	rack = (struct tcp_rack *)tp->t_fb_ptr;
19305 	if (rack->r_ctl.rc_pace_min_segs != ctf_fixed_maxseg(tp)) {
19306 		/*
19307 		 * The MTU has changed we need to resend everything
19308 		 * since all we have sent is lost. We first fix
19309 		 * up the mtu though.
19310 		 */
19311 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
19312 		/* We treat this like a full retransmit timeout without the cwnd adjustment */
19313 		rack_remxt_tmr(tp);
19314 		rack->r_fast_output = 0;
19315 		rack->r_ctl.rc_out_at_rto = ctf_flight_size(tp,
19316 						rack->r_ctl.rc_sacked);
19317 		rack->r_ctl.rc_snd_max_at_rto = tp->snd_max;
19318 		rack->r_must_retran = 1;
19319 		/* Mark all inflight to needing to be rxt'd */
19320 		TAILQ_FOREACH(rsm, &rack->r_ctl.rc_tmap, r_tnext) {
19321 			rsm->r_flags |= RACK_MUST_RXT;
19322 		}
19323 	}
19324 	sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
19325 	/* We don't use snd_nxt to retransmit */
19326 	tp->snd_nxt = tp->snd_max;
19327 }
19328 
19329 static int
19330 rack_set_profile(struct tcp_rack *rack, int prof)
19331 {
19332 	int err = EINVAL;
19333 	if (prof == 1) {
19334 		/* pace_always=1 */
19335 		if (rack->rc_always_pace == 0) {
19336 			if (tcp_can_enable_pacing() == 0)
19337 				return (EBUSY);
19338 		}
19339 		rack->rc_always_pace = 1;
19340 		if (rack->use_fixed_rate || rack->gp_ready)
19341 			rack_set_cc_pacing(rack);
19342 		rack->rc_inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19343 		rack->rack_attempt_hdwr_pace = 0;
19344 		/* cmpack=1 */
19345 		if (rack_use_cmp_acks)
19346 			rack->r_use_cmp_ack = 1;
19347 		if (TCPS_HAVEESTABLISHED(rack->rc_tp->t_state) &&
19348 		    rack->r_use_cmp_ack)
19349 			rack->rc_inp->inp_flags2 |= INP_MBUF_ACKCMP;
19350 		/* scwnd=1 */
19351 		rack->rack_enable_scwnd = 1;
19352 		/* dynamic=100 */
19353 		rack->rc_gp_dyn_mul = 1;
19354 		/* gp_inc_ca */
19355 		rack->r_ctl.rack_per_of_gp_ca = 100;
19356 		/* rrr_conf=3 */
19357 		rack->r_rr_config = 3;
19358 		/* npush=2 */
19359 		rack->r_ctl.rc_no_push_at_mrtt = 2;
19360 		/* fillcw=1 */
19361 		rack->rc_pace_to_cwnd = 1;
19362 		rack->rc_pace_fill_if_rttin_range = 0;
19363 		rack->rtt_limit_mul = 0;
19364 		/* noprr=1 */
19365 		rack->rack_no_prr = 1;
19366 		/* lscwnd=1 */
19367 		rack->r_limit_scw = 1;
19368 		/* gp_inc_rec */
19369 		rack->r_ctl.rack_per_of_gp_rec = 90;
19370 		err = 0;
19371 
19372 	} else if (prof == 3) {
19373 		/* Same as profile one execept fill_cw becomes 2 (less aggressive set) */
19374 		/* pace_always=1 */
19375 		if (rack->rc_always_pace == 0) {
19376 			if (tcp_can_enable_pacing() == 0)
19377 				return (EBUSY);
19378 		}
19379 		rack->rc_always_pace = 1;
19380 		if (rack->use_fixed_rate || rack->gp_ready)
19381 			rack_set_cc_pacing(rack);
19382 		rack->rc_inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19383 		rack->rack_attempt_hdwr_pace = 0;
19384 		/* cmpack=1 */
19385 		if (rack_use_cmp_acks)
19386 			rack->r_use_cmp_ack = 1;
19387 		if (TCPS_HAVEESTABLISHED(rack->rc_tp->t_state) &&
19388 		    rack->r_use_cmp_ack)
19389 			rack->rc_inp->inp_flags2 |= INP_MBUF_ACKCMP;
19390 		/* scwnd=1 */
19391 		rack->rack_enable_scwnd = 1;
19392 		/* dynamic=100 */
19393 		rack->rc_gp_dyn_mul = 1;
19394 		/* gp_inc_ca */
19395 		rack->r_ctl.rack_per_of_gp_ca = 100;
19396 		/* rrr_conf=3 */
19397 		rack->r_rr_config = 3;
19398 		/* npush=2 */
19399 		rack->r_ctl.rc_no_push_at_mrtt = 2;
19400 		/* fillcw=2 */
19401 		rack->rc_pace_to_cwnd = 1;
19402 		rack->r_fill_less_agg = 1;
19403 		rack->rc_pace_fill_if_rttin_range = 0;
19404 		rack->rtt_limit_mul = 0;
19405 		/* noprr=1 */
19406 		rack->rack_no_prr = 1;
19407 		/* lscwnd=1 */
19408 		rack->r_limit_scw = 1;
19409 		/* gp_inc_rec */
19410 		rack->r_ctl.rack_per_of_gp_rec = 90;
19411 		err = 0;
19412 
19413 
19414 	} else if (prof == 2) {
19415 		/* cmpack=1 */
19416 		if (rack->rc_always_pace == 0) {
19417 			if (tcp_can_enable_pacing() == 0)
19418 				return (EBUSY);
19419 		}
19420 		rack->rc_always_pace = 1;
19421 		if (rack->use_fixed_rate || rack->gp_ready)
19422 			rack_set_cc_pacing(rack);
19423 		rack->r_use_cmp_ack = 1;
19424 		if (TCPS_HAVEESTABLISHED(rack->rc_tp->t_state))
19425 			rack->rc_inp->inp_flags2 |= INP_MBUF_ACKCMP;
19426 		/* pace_always=1 */
19427 		rack->rc_inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19428 		/* scwnd=1 */
19429 		rack->rack_enable_scwnd = 1;
19430 		/* dynamic=100 */
19431 		rack->rc_gp_dyn_mul = 1;
19432 		rack->r_ctl.rack_per_of_gp_ca = 100;
19433 		/* rrr_conf=3 */
19434 		rack->r_rr_config = 3;
19435 		/* npush=2 */
19436 		rack->r_ctl.rc_no_push_at_mrtt = 2;
19437 		/* fillcw=1 */
19438 		rack->rc_pace_to_cwnd = 1;
19439 		rack->rc_pace_fill_if_rttin_range = 0;
19440 		rack->rtt_limit_mul = 0;
19441 		/* noprr=1 */
19442 		rack->rack_no_prr = 1;
19443 		/* lscwnd=0 */
19444 		rack->r_limit_scw = 0;
19445 		err = 0;
19446 	} else if (prof == 0) {
19447 		/* This changes things back to the default settings */
19448 		err = 0;
19449 		if (rack->rc_always_pace) {
19450 			tcp_decrement_paced_conn();
19451 			rack_undo_cc_pacing(rack);
19452 			rack->rc_always_pace = 0;
19453 		}
19454 		if (rack_pace_every_seg && tcp_can_enable_pacing()) {
19455 			rack->rc_always_pace = 1;
19456 			if (rack->use_fixed_rate || rack->gp_ready)
19457 				rack_set_cc_pacing(rack);
19458 		} else
19459 			rack->rc_always_pace = 0;
19460 		if (rack_dsack_std_based & 0x1) {
19461 			/* Basically this means all rack timers are at least (srtt + 1/4 srtt) */
19462 			rack->rc_rack_tmr_std_based = 1;
19463 		}
19464 		if (rack_dsack_std_based & 0x2) {
19465 			/* Basically this means  rack timers are extended based on dsack by up to (2 * srtt) */
19466 			rack->rc_rack_use_dsack = 1;
19467 		}
19468 		if (rack_use_cmp_acks)
19469 			rack->r_use_cmp_ack = 1;
19470 		else
19471 			rack->r_use_cmp_ack = 0;
19472 		if (rack_disable_prr)
19473 			rack->rack_no_prr = 1;
19474 		else
19475 			rack->rack_no_prr = 0;
19476 		if (rack_gp_no_rec_chg)
19477 			rack->rc_gp_no_rec_chg = 1;
19478 		else
19479 			rack->rc_gp_no_rec_chg = 0;
19480 		if (rack_enable_mqueue_for_nonpaced || rack->r_use_cmp_ack) {
19481 			rack->r_mbuf_queue = 1;
19482 			if (TCPS_HAVEESTABLISHED(rack->rc_tp->t_state))
19483 				rack->rc_inp->inp_flags2 |= INP_MBUF_ACKCMP;
19484 			rack->rc_inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19485 		} else {
19486 			rack->r_mbuf_queue = 0;
19487 			rack->rc_inp->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
19488 		}
19489 		if (rack_enable_shared_cwnd)
19490 			rack->rack_enable_scwnd = 1;
19491 		else
19492 			rack->rack_enable_scwnd = 0;
19493 		if (rack_do_dyn_mul) {
19494 			/* When dynamic adjustment is on CA needs to start at 100% */
19495 			rack->rc_gp_dyn_mul = 1;
19496 			if (rack_do_dyn_mul >= 100)
19497 				rack->r_ctl.rack_per_of_gp_ca = rack_do_dyn_mul;
19498 		} else {
19499 			rack->r_ctl.rack_per_of_gp_ca = rack_per_of_gp_ca;
19500 			rack->rc_gp_dyn_mul = 0;
19501 		}
19502 		rack->r_rr_config = 0;
19503 		rack->r_ctl.rc_no_push_at_mrtt = 0;
19504 		rack->rc_pace_to_cwnd = 0;
19505 		rack->rc_pace_fill_if_rttin_range = 0;
19506 		rack->rtt_limit_mul = 0;
19507 
19508 		if (rack_enable_hw_pacing)
19509 			rack->rack_hdw_pace_ena = 1;
19510 		else
19511 			rack->rack_hdw_pace_ena = 0;
19512 		if (rack_disable_prr)
19513 			rack->rack_no_prr = 1;
19514 		else
19515 			rack->rack_no_prr = 0;
19516 		if (rack_limits_scwnd)
19517 			rack->r_limit_scw  = 1;
19518 		else
19519 			rack->r_limit_scw  = 0;
19520 		err = 0;
19521 	}
19522 	return (err);
19523 }
19524 
19525 static int
19526 rack_add_deferred_option(struct tcp_rack *rack, int sopt_name, uint64_t loptval)
19527 {
19528 	struct deferred_opt_list *dol;
19529 
19530 	dol = malloc(sizeof(struct deferred_opt_list),
19531 		     M_TCPFSB, M_NOWAIT|M_ZERO);
19532 	if (dol == NULL) {
19533 		/*
19534 		 * No space yikes -- fail out..
19535 		 */
19536 		return (0);
19537 	}
19538 	dol->optname = sopt_name;
19539 	dol->optval = loptval;
19540 	TAILQ_INSERT_TAIL(&rack->r_ctl.opt_list, dol, next);
19541 	return (1);
19542 }
19543 
19544 static int
19545 rack_process_option(struct tcpcb *tp, struct tcp_rack *rack, int sopt_name,
19546 		    uint32_t optval, uint64_t loptval)
19547 {
19548 	struct epoch_tracker et;
19549 	struct sockopt sopt;
19550 	struct cc_newreno_opts opt;
19551 	struct inpcb *inp = tptoinpcb(tp);
19552 	uint64_t val;
19553 	int error = 0;
19554 	uint16_t ca, ss;
19555 
19556 	switch (sopt_name) {
19557 
19558 	case TCP_RACK_DSACK_OPT:
19559 		RACK_OPTS_INC(tcp_rack_dsack_opt);
19560 		if (optval & 0x1) {
19561 			rack->rc_rack_tmr_std_based = 1;
19562 		} else {
19563 			rack->rc_rack_tmr_std_based = 0;
19564 		}
19565 		if (optval & 0x2) {
19566 			rack->rc_rack_use_dsack = 1;
19567 		} else {
19568 			rack->rc_rack_use_dsack = 0;
19569 		}
19570 		rack_log_dsack_event(rack, 5, __LINE__, 0, 0);
19571 		break;
19572 	case TCP_RACK_PACING_BETA:
19573 		RACK_OPTS_INC(tcp_rack_beta);
19574 		if (strcmp(tp->t_cc->name, CCALGONAME_NEWRENO) != 0) {
19575 			/* This only works for newreno. */
19576 			error = EINVAL;
19577 			break;
19578 		}
19579 		if (rack->rc_pacing_cc_set) {
19580 			/*
19581 			 * Set them into the real CC module
19582 			 * whats in the rack pcb is the old values
19583 			 * to be used on restoral/
19584 			 */
19585 			sopt.sopt_dir = SOPT_SET;
19586 			opt.name = CC_NEWRENO_BETA;
19587 			opt.val = optval;
19588 			if (CC_ALGO(tp)->ctl_output != NULL)
19589 				error = CC_ALGO(tp)->ctl_output(&tp->t_ccv, &sopt, &opt);
19590 			else {
19591 				error = ENOENT;
19592 				break;
19593 			}
19594 		} else {
19595 			/*
19596 			 * Not pacing yet so set it into our local
19597 			 * rack pcb storage.
19598 			 */
19599 			rack->r_ctl.rc_saved_beta.beta = optval;
19600 		}
19601 		break;
19602 	case TCP_RACK_TIMER_SLOP:
19603 		RACK_OPTS_INC(tcp_rack_timer_slop);
19604 		rack->r_ctl.timer_slop = optval;
19605 		if (rack->rc_tp->t_srtt) {
19606 			/*
19607 			 * If we have an SRTT lets update t_rxtcur
19608 			 * to have the new slop.
19609 			 */
19610 			RACK_TCPT_RANGESET(tp->t_rxtcur, RACK_REXMTVAL(tp),
19611 					   rack_rto_min, rack_rto_max,
19612 					   rack->r_ctl.timer_slop);
19613 		}
19614 		break;
19615 	case TCP_RACK_PACING_BETA_ECN:
19616 		RACK_OPTS_INC(tcp_rack_beta_ecn);
19617 		if (strcmp(tp->t_cc->name, CCALGONAME_NEWRENO) != 0) {
19618 			/* This only works for newreno. */
19619 			error = EINVAL;
19620 			break;
19621 		}
19622 		if (rack->rc_pacing_cc_set) {
19623 			/*
19624 			 * Set them into the real CC module
19625 			 * whats in the rack pcb is the old values
19626 			 * to be used on restoral/
19627 			 */
19628 			sopt.sopt_dir = SOPT_SET;
19629 			opt.name = CC_NEWRENO_BETA_ECN;
19630 			opt.val = optval;
19631 			if (CC_ALGO(tp)->ctl_output != NULL)
19632 				error = CC_ALGO(tp)->ctl_output(&tp->t_ccv, &sopt, &opt);
19633 			else
19634 				error = ENOENT;
19635 		} else {
19636 			/*
19637 			 * Not pacing yet so set it into our local
19638 			 * rack pcb storage.
19639 			 */
19640 			rack->r_ctl.rc_saved_beta.beta_ecn = optval;
19641 			rack->r_ctl.rc_saved_beta.newreno_flags = CC_NEWRENO_BETA_ECN_ENABLED;
19642 		}
19643 		break;
19644 	case TCP_DEFER_OPTIONS:
19645 		RACK_OPTS_INC(tcp_defer_opt);
19646 		if (optval) {
19647 			if (rack->gp_ready) {
19648 				/* Too late */
19649 				error = EINVAL;
19650 				break;
19651 			}
19652 			rack->defer_options = 1;
19653 		} else
19654 			rack->defer_options = 0;
19655 		break;
19656 	case TCP_RACK_MEASURE_CNT:
19657 		RACK_OPTS_INC(tcp_rack_measure_cnt);
19658 		if (optval && (optval <= 0xff)) {
19659 			rack->r_ctl.req_measurements = optval;
19660 		} else
19661 			error = EINVAL;
19662 		break;
19663 	case TCP_REC_ABC_VAL:
19664 		RACK_OPTS_INC(tcp_rec_abc_val);
19665 		if (optval > 0)
19666 			rack->r_use_labc_for_rec = 1;
19667 		else
19668 			rack->r_use_labc_for_rec = 0;
19669 		break;
19670 	case TCP_RACK_ABC_VAL:
19671 		RACK_OPTS_INC(tcp_rack_abc_val);
19672 		if ((optval > 0) && (optval < 255))
19673 			rack->rc_labc = optval;
19674 		else
19675 			error = EINVAL;
19676 		break;
19677 	case TCP_HDWR_UP_ONLY:
19678 		RACK_OPTS_INC(tcp_pacing_up_only);
19679 		if (optval)
19680 			rack->r_up_only = 1;
19681 		else
19682 			rack->r_up_only = 0;
19683 		break;
19684 	case TCP_PACING_RATE_CAP:
19685 		RACK_OPTS_INC(tcp_pacing_rate_cap);
19686 		rack->r_ctl.bw_rate_cap = loptval;
19687 		break;
19688 	case TCP_RACK_PROFILE:
19689 		RACK_OPTS_INC(tcp_profile);
19690 		error = rack_set_profile(rack, optval);
19691 		break;
19692 	case TCP_USE_CMP_ACKS:
19693 		RACK_OPTS_INC(tcp_use_cmp_acks);
19694 		if ((optval == 0) && (rack->rc_inp->inp_flags2 & INP_MBUF_ACKCMP)) {
19695 			/* You can't turn it off once its on! */
19696 			error = EINVAL;
19697 		} else if ((optval == 1) && (rack->r_use_cmp_ack == 0)) {
19698 			rack->r_use_cmp_ack = 1;
19699 			rack->r_mbuf_queue = 1;
19700 			inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19701 		}
19702 		if (rack->r_use_cmp_ack && TCPS_HAVEESTABLISHED(tp->t_state))
19703 			inp->inp_flags2 |= INP_MBUF_ACKCMP;
19704 		break;
19705 	case TCP_SHARED_CWND_TIME_LIMIT:
19706 		RACK_OPTS_INC(tcp_lscwnd);
19707 		if (optval)
19708 			rack->r_limit_scw = 1;
19709 		else
19710 			rack->r_limit_scw = 0;
19711 		break;
19712  	case TCP_RACK_PACE_TO_FILL:
19713 		RACK_OPTS_INC(tcp_fillcw);
19714 		if (optval == 0)
19715 			rack->rc_pace_to_cwnd = 0;
19716 		else {
19717 			rack->rc_pace_to_cwnd = 1;
19718 			if (optval > 1)
19719 				rack->r_fill_less_agg = 1;
19720 		}
19721 		if ((optval >= rack_gp_rtt_maxmul) &&
19722 		    rack_gp_rtt_maxmul &&
19723 		    (optval < 0xf)) {
19724 			rack->rc_pace_fill_if_rttin_range = 1;
19725 			rack->rtt_limit_mul = optval;
19726 		} else {
19727 			rack->rc_pace_fill_if_rttin_range = 0;
19728 			rack->rtt_limit_mul = 0;
19729 		}
19730 		break;
19731 	case TCP_RACK_NO_PUSH_AT_MAX:
19732 		RACK_OPTS_INC(tcp_npush);
19733 		if (optval == 0)
19734 			rack->r_ctl.rc_no_push_at_mrtt = 0;
19735 		else if (optval < 0xff)
19736 			rack->r_ctl.rc_no_push_at_mrtt = optval;
19737 		else
19738 			error = EINVAL;
19739 		break;
19740 	case TCP_SHARED_CWND_ENABLE:
19741 		RACK_OPTS_INC(tcp_rack_scwnd);
19742 		if (optval == 0)
19743 			rack->rack_enable_scwnd = 0;
19744 		else
19745 			rack->rack_enable_scwnd = 1;
19746 		break;
19747 	case TCP_RACK_MBUF_QUEUE:
19748 		/* Now do we use the LRO mbuf-queue feature */
19749 		RACK_OPTS_INC(tcp_rack_mbufq);
19750 		if (optval || rack->r_use_cmp_ack)
19751 			rack->r_mbuf_queue = 1;
19752 		else
19753 			rack->r_mbuf_queue = 0;
19754 		if  (rack->r_mbuf_queue || rack->rc_always_pace || rack->r_use_cmp_ack)
19755 			inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19756 		else
19757 			inp->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
19758 		break;
19759 	case TCP_RACK_NONRXT_CFG_RATE:
19760 		RACK_OPTS_INC(tcp_rack_cfg_rate);
19761 		if (optval == 0)
19762 			rack->rack_rec_nonrxt_use_cr = 0;
19763 		else
19764 			rack->rack_rec_nonrxt_use_cr = 1;
19765 		break;
19766 	case TCP_NO_PRR:
19767 		RACK_OPTS_INC(tcp_rack_noprr);
19768 		if (optval == 0)
19769 			rack->rack_no_prr = 0;
19770 		else if (optval == 1)
19771 			rack->rack_no_prr = 1;
19772 		else if (optval == 2)
19773 			rack->no_prr_addback = 1;
19774 		else
19775 			error = EINVAL;
19776 		break;
19777 	case TCP_TIMELY_DYN_ADJ:
19778 		RACK_OPTS_INC(tcp_timely_dyn);
19779 		if (optval == 0)
19780 			rack->rc_gp_dyn_mul = 0;
19781 		else {
19782 			rack->rc_gp_dyn_mul = 1;
19783 			if (optval >= 100) {
19784 				/*
19785 				 * If the user sets something 100 or more
19786 				 * its the gp_ca value.
19787 				 */
19788 				rack->r_ctl.rack_per_of_gp_ca  = optval;
19789 			}
19790 		}
19791 		break;
19792 	case TCP_RACK_DO_DETECTION:
19793 		RACK_OPTS_INC(tcp_rack_do_detection);
19794 		if (optval == 0)
19795 			rack->do_detection = 0;
19796 		else
19797 			rack->do_detection = 1;
19798 		break;
19799 	case TCP_RACK_TLP_USE:
19800 		if ((optval < TLP_USE_ID) || (optval > TLP_USE_TWO_TWO)) {
19801 			error = EINVAL;
19802 			break;
19803 		}
19804 		RACK_OPTS_INC(tcp_tlp_use);
19805 		rack->rack_tlp_threshold_use = optval;
19806 		break;
19807 	case TCP_RACK_TLP_REDUCE:
19808 		/* RACK TLP cwnd reduction (bool) */
19809 		RACK_OPTS_INC(tcp_rack_tlp_reduce);
19810 		rack->r_ctl.rc_tlp_cwnd_reduce = optval;
19811 		break;
19812 	/*  Pacing related ones */
19813 	case TCP_RACK_PACE_ALWAYS:
19814 		/*
19815 		 * zero is old rack method, 1 is new
19816 		 * method using a pacing rate.
19817 		 */
19818 		RACK_OPTS_INC(tcp_rack_pace_always);
19819 		if (optval > 0) {
19820 			if (rack->rc_always_pace) {
19821 				error = EALREADY;
19822 				break;
19823 			} else if (tcp_can_enable_pacing()) {
19824 				rack->rc_always_pace = 1;
19825 				if (rack->use_fixed_rate || rack->gp_ready)
19826 					rack_set_cc_pacing(rack);
19827 			}
19828 			else {
19829 				error = ENOSPC;
19830 				break;
19831 			}
19832 		} else {
19833 			if (rack->rc_always_pace) {
19834 				tcp_decrement_paced_conn();
19835 				rack->rc_always_pace = 0;
19836 				rack_undo_cc_pacing(rack);
19837 			}
19838 		}
19839 		if  (rack->r_mbuf_queue || rack->rc_always_pace || rack->r_use_cmp_ack)
19840 			inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
19841 		else
19842 			inp->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
19843 		/* A rate may be set irate or other, if so set seg size */
19844 		rack_update_seg(rack);
19845 		break;
19846 	case TCP_BBR_RACK_INIT_RATE:
19847 		RACK_OPTS_INC(tcp_initial_rate);
19848 		val = optval;
19849 		/* Change from kbits per second to bytes per second */
19850 		val *= 1000;
19851 		val /= 8;
19852 		rack->r_ctl.init_rate = val;
19853 		if (rack->rc_init_win != rack_default_init_window) {
19854 			uint32_t win, snt;
19855 
19856 			/*
19857 			 * Options don't always get applied
19858 			 * in the order you think. So in order
19859 			 * to assure we update a cwnd we need
19860 			 * to check and see if we are still
19861 			 * where we should raise the cwnd.
19862 			 */
19863 			win = rc_init_window(rack);
19864 			if (SEQ_GT(tp->snd_max, tp->iss))
19865 				snt = tp->snd_max - tp->iss;
19866 			else
19867 				snt = 0;
19868 			if ((snt < win) &&
19869 			    (tp->snd_cwnd < win))
19870 				tp->snd_cwnd = win;
19871 		}
19872 		if (rack->rc_always_pace)
19873 			rack_update_seg(rack);
19874 		break;
19875 	case TCP_BBR_IWINTSO:
19876 		RACK_OPTS_INC(tcp_initial_win);
19877 		if (optval && (optval <= 0xff)) {
19878 			uint32_t win, snt;
19879 
19880 			rack->rc_init_win = optval;
19881 			win = rc_init_window(rack);
19882 			if (SEQ_GT(tp->snd_max, tp->iss))
19883 				snt = tp->snd_max - tp->iss;
19884 			else
19885 				snt = 0;
19886 			if ((snt < win) &&
19887 			    (tp->t_srtt |
19888 #ifdef NETFLIX_PEAKRATE
19889 			     tp->t_maxpeakrate |
19890 #endif
19891 			     rack->r_ctl.init_rate)) {
19892 				/*
19893 				 * We are not past the initial window
19894 				 * and we have some bases for pacing,
19895 				 * so we need to possibly adjust up
19896 				 * the cwnd. Note even if we don't set
19897 				 * the cwnd, its still ok to raise the rc_init_win
19898 				 * which can be used coming out of idle when we
19899 				 * would have a rate.
19900 				 */
19901 				if (tp->snd_cwnd < win)
19902 					tp->snd_cwnd = win;
19903 			}
19904 			if (rack->rc_always_pace)
19905 				rack_update_seg(rack);
19906 		} else
19907 			error = EINVAL;
19908 		break;
19909 	case TCP_RACK_FORCE_MSEG:
19910 		RACK_OPTS_INC(tcp_rack_force_max_seg);
19911 		if (optval)
19912 			rack->rc_force_max_seg = 1;
19913 		else
19914 			rack->rc_force_max_seg = 0;
19915 		break;
19916 	case TCP_RACK_PACE_MAX_SEG:
19917 		/* Max segments size in a pace in bytes */
19918 		RACK_OPTS_INC(tcp_rack_max_seg);
19919 		rack->rc_user_set_max_segs = optval;
19920 		rack_set_pace_segments(tp, rack, __LINE__, NULL);
19921 		break;
19922 	case TCP_RACK_PACE_RATE_REC:
19923 		/* Set the fixed pacing rate in Bytes per second ca */
19924 		RACK_OPTS_INC(tcp_rack_pace_rate_rec);
19925 		rack->r_ctl.rc_fixed_pacing_rate_rec = optval;
19926 		if (rack->r_ctl.rc_fixed_pacing_rate_ca == 0)
19927 			rack->r_ctl.rc_fixed_pacing_rate_ca = optval;
19928 		if (rack->r_ctl.rc_fixed_pacing_rate_ss == 0)
19929 			rack->r_ctl.rc_fixed_pacing_rate_ss = optval;
19930 		rack->use_fixed_rate = 1;
19931 		if (rack->rc_always_pace)
19932 			rack_set_cc_pacing(rack);
19933 		rack_log_pacing_delay_calc(rack,
19934 					   rack->r_ctl.rc_fixed_pacing_rate_ss,
19935 					   rack->r_ctl.rc_fixed_pacing_rate_ca,
19936 					   rack->r_ctl.rc_fixed_pacing_rate_rec, 0, 0, 8,
19937 					   __LINE__, NULL,0);
19938 		break;
19939 
19940 	case TCP_RACK_PACE_RATE_SS:
19941 		/* Set the fixed pacing rate in Bytes per second ca */
19942 		RACK_OPTS_INC(tcp_rack_pace_rate_ss);
19943 		rack->r_ctl.rc_fixed_pacing_rate_ss = optval;
19944 		if (rack->r_ctl.rc_fixed_pacing_rate_ca == 0)
19945 			rack->r_ctl.rc_fixed_pacing_rate_ca = optval;
19946 		if (rack->r_ctl.rc_fixed_pacing_rate_rec == 0)
19947 			rack->r_ctl.rc_fixed_pacing_rate_rec = optval;
19948 		rack->use_fixed_rate = 1;
19949 		if (rack->rc_always_pace)
19950 			rack_set_cc_pacing(rack);
19951 		rack_log_pacing_delay_calc(rack,
19952 					   rack->r_ctl.rc_fixed_pacing_rate_ss,
19953 					   rack->r_ctl.rc_fixed_pacing_rate_ca,
19954 					   rack->r_ctl.rc_fixed_pacing_rate_rec, 0, 0, 8,
19955 					   __LINE__, NULL, 0);
19956 		break;
19957 
19958 	case TCP_RACK_PACE_RATE_CA:
19959 		/* Set the fixed pacing rate in Bytes per second ca */
19960 		RACK_OPTS_INC(tcp_rack_pace_rate_ca);
19961 		rack->r_ctl.rc_fixed_pacing_rate_ca = optval;
19962 		if (rack->r_ctl.rc_fixed_pacing_rate_ss == 0)
19963 			rack->r_ctl.rc_fixed_pacing_rate_ss = optval;
19964 		if (rack->r_ctl.rc_fixed_pacing_rate_rec == 0)
19965 			rack->r_ctl.rc_fixed_pacing_rate_rec = optval;
19966 		rack->use_fixed_rate = 1;
19967 		if (rack->rc_always_pace)
19968 			rack_set_cc_pacing(rack);
19969 		rack_log_pacing_delay_calc(rack,
19970 					   rack->r_ctl.rc_fixed_pacing_rate_ss,
19971 					   rack->r_ctl.rc_fixed_pacing_rate_ca,
19972 					   rack->r_ctl.rc_fixed_pacing_rate_rec, 0, 0, 8,
19973 					   __LINE__, NULL, 0);
19974 		break;
19975 	case TCP_RACK_GP_INCREASE_REC:
19976 		RACK_OPTS_INC(tcp_gp_inc_rec);
19977 		rack->r_ctl.rack_per_of_gp_rec = optval;
19978 		rack_log_pacing_delay_calc(rack,
19979 					   rack->r_ctl.rack_per_of_gp_ss,
19980 					   rack->r_ctl.rack_per_of_gp_ca,
19981 					   rack->r_ctl.rack_per_of_gp_rec, 0, 0, 1,
19982 					   __LINE__, NULL, 0);
19983 		break;
19984 	case TCP_RACK_GP_INCREASE_CA:
19985 		RACK_OPTS_INC(tcp_gp_inc_ca);
19986 		ca = optval;
19987 		if (ca < 100) {
19988 			/*
19989 			 * We don't allow any reduction
19990 			 * over the GP b/w.
19991 			 */
19992 			error = EINVAL;
19993 			break;
19994 		}
19995 		rack->r_ctl.rack_per_of_gp_ca = ca;
19996 		rack_log_pacing_delay_calc(rack,
19997 					   rack->r_ctl.rack_per_of_gp_ss,
19998 					   rack->r_ctl.rack_per_of_gp_ca,
19999 					   rack->r_ctl.rack_per_of_gp_rec, 0, 0, 1,
20000 					   __LINE__, NULL, 0);
20001 		break;
20002 	case TCP_RACK_GP_INCREASE_SS:
20003 		RACK_OPTS_INC(tcp_gp_inc_ss);
20004 		ss = optval;
20005 		if (ss < 100) {
20006 			/*
20007 			 * We don't allow any reduction
20008 			 * over the GP b/w.
20009 			 */
20010 			error = EINVAL;
20011 			break;
20012 		}
20013 		rack->r_ctl.rack_per_of_gp_ss = ss;
20014 		rack_log_pacing_delay_calc(rack,
20015 					   rack->r_ctl.rack_per_of_gp_ss,
20016 					   rack->r_ctl.rack_per_of_gp_ca,
20017 					   rack->r_ctl.rack_per_of_gp_rec, 0, 0, 1,
20018 					   __LINE__, NULL, 0);
20019 		break;
20020 	case TCP_RACK_RR_CONF:
20021 		RACK_OPTS_INC(tcp_rack_rrr_no_conf_rate);
20022 		if (optval && optval <= 3)
20023 			rack->r_rr_config = optval;
20024 		else
20025 			rack->r_rr_config = 0;
20026 		break;
20027 	case TCP_HDWR_RATE_CAP:
20028 		RACK_OPTS_INC(tcp_hdwr_rate_cap);
20029 		if (optval) {
20030 			if (rack->r_rack_hw_rate_caps == 0)
20031 				rack->r_rack_hw_rate_caps = 1;
20032 			else
20033 				error = EALREADY;
20034 		} else {
20035 			rack->r_rack_hw_rate_caps = 0;
20036 		}
20037 		break;
20038 	case TCP_BBR_HDWR_PACE:
20039 		RACK_OPTS_INC(tcp_hdwr_pacing);
20040 		if (optval){
20041 			if (rack->rack_hdrw_pacing == 0) {
20042 				rack->rack_hdw_pace_ena = 1;
20043 				rack->rack_attempt_hdwr_pace = 0;
20044 			} else
20045 				error = EALREADY;
20046 		} else {
20047 			rack->rack_hdw_pace_ena = 0;
20048 #ifdef RATELIMIT
20049 			if (rack->r_ctl.crte != NULL) {
20050 				rack->rack_hdrw_pacing = 0;
20051 				rack->rack_attempt_hdwr_pace = 0;
20052 				tcp_rel_pacing_rate(rack->r_ctl.crte, tp);
20053 				rack->r_ctl.crte = NULL;
20054 			}
20055 #endif
20056 		}
20057 		break;
20058 	/*  End Pacing related ones */
20059 	case TCP_RACK_PRR_SENDALOT:
20060 		/* Allow PRR to send more than one seg */
20061 		RACK_OPTS_INC(tcp_rack_prr_sendalot);
20062 		rack->r_ctl.rc_prr_sendalot = optval;
20063 		break;
20064 	case TCP_RACK_MIN_TO:
20065 		/* Minimum time between rack t-o's in ms */
20066 		RACK_OPTS_INC(tcp_rack_min_to);
20067 		rack->r_ctl.rc_min_to = optval;
20068 		break;
20069 	case TCP_RACK_EARLY_SEG:
20070 		/* If early recovery max segments */
20071 		RACK_OPTS_INC(tcp_rack_early_seg);
20072 		rack->r_ctl.rc_early_recovery_segs = optval;
20073 		break;
20074 	case TCP_RACK_ENABLE_HYSTART:
20075 	{
20076 		if (optval) {
20077 			tp->t_ccv.flags |= CCF_HYSTART_ALLOWED;
20078 			if (rack_do_hystart > RACK_HYSTART_ON)
20079 				tp->t_ccv.flags |= CCF_HYSTART_CAN_SH_CWND;
20080 			if (rack_do_hystart > RACK_HYSTART_ON_W_SC)
20081 				tp->t_ccv.flags |= CCF_HYSTART_CONS_SSTH;
20082 		} else {
20083 			tp->t_ccv.flags &= ~(CCF_HYSTART_ALLOWED|CCF_HYSTART_CAN_SH_CWND|CCF_HYSTART_CONS_SSTH);
20084 		}
20085 	}
20086 	break;
20087 	case TCP_RACK_REORD_THRESH:
20088 		/* RACK reorder threshold (shift amount) */
20089 		RACK_OPTS_INC(tcp_rack_reord_thresh);
20090 		if ((optval > 0) && (optval < 31))
20091 			rack->r_ctl.rc_reorder_shift = optval;
20092 		else
20093 			error = EINVAL;
20094 		break;
20095 	case TCP_RACK_REORD_FADE:
20096 		/* Does reordering fade after ms time */
20097 		RACK_OPTS_INC(tcp_rack_reord_fade);
20098 		rack->r_ctl.rc_reorder_fade = optval;
20099 		break;
20100 	case TCP_RACK_TLP_THRESH:
20101 		/* RACK TLP theshold i.e. srtt+(srtt/N) */
20102 		RACK_OPTS_INC(tcp_rack_tlp_thresh);
20103 		if (optval)
20104 			rack->r_ctl.rc_tlp_threshold = optval;
20105 		else
20106 			error = EINVAL;
20107 		break;
20108 	case TCP_BBR_USE_RACK_RR:
20109 		RACK_OPTS_INC(tcp_rack_rr);
20110 		if (optval)
20111 			rack->use_rack_rr = 1;
20112 		else
20113 			rack->use_rack_rr = 0;
20114 		break;
20115 	case TCP_FAST_RSM_HACK:
20116 		RACK_OPTS_INC(tcp_rack_fastrsm_hack);
20117 		if (optval)
20118 			rack->fast_rsm_hack = 1;
20119 		else
20120 			rack->fast_rsm_hack = 0;
20121 		break;
20122 	case TCP_RACK_PKT_DELAY:
20123 		/* RACK added ms i.e. rack-rtt + reord + N */
20124 		RACK_OPTS_INC(tcp_rack_pkt_delay);
20125 		rack->r_ctl.rc_pkt_delay = optval;
20126 		break;
20127 	case TCP_DELACK:
20128 		RACK_OPTS_INC(tcp_rack_delayed_ack);
20129 		if (optval == 0)
20130 			tp->t_delayed_ack = 0;
20131 		else
20132 			tp->t_delayed_ack = 1;
20133 		if (tp->t_flags & TF_DELACK) {
20134 			tp->t_flags &= ~TF_DELACK;
20135 			tp->t_flags |= TF_ACKNOW;
20136 			NET_EPOCH_ENTER(et);
20137 			rack_output(tp);
20138 			NET_EPOCH_EXIT(et);
20139 		}
20140 		break;
20141 
20142 	case TCP_BBR_RACK_RTT_USE:
20143 		RACK_OPTS_INC(tcp_rack_rtt_use);
20144 		if ((optval != USE_RTT_HIGH) &&
20145 		    (optval != USE_RTT_LOW) &&
20146 		    (optval != USE_RTT_AVG))
20147 			error = EINVAL;
20148 		else
20149 			rack->r_ctl.rc_rate_sample_method = optval;
20150 		break;
20151 	case TCP_DATA_AFTER_CLOSE:
20152 		RACK_OPTS_INC(tcp_data_after_close);
20153 		if (optval)
20154 			rack->rc_allow_data_af_clo = 1;
20155 		else
20156 			rack->rc_allow_data_af_clo = 0;
20157 		break;
20158 	default:
20159 		break;
20160 	}
20161 #ifdef NETFLIX_STATS
20162 	tcp_log_socket_option(tp, sopt_name, optval, error);
20163 #endif
20164 	return (error);
20165 }
20166 
20167 
20168 static void
20169 rack_apply_deferred_options(struct tcp_rack *rack)
20170 {
20171 	struct deferred_opt_list *dol, *sdol;
20172 	uint32_t s_optval;
20173 
20174 	TAILQ_FOREACH_SAFE(dol, &rack->r_ctl.opt_list, next, sdol) {
20175 		TAILQ_REMOVE(&rack->r_ctl.opt_list, dol, next);
20176 		/* Disadvantage of deferal is you loose the error return */
20177 		s_optval = (uint32_t)dol->optval;
20178 		(void)rack_process_option(rack->rc_tp, rack, dol->optname, s_optval, dol->optval);
20179 		free(dol, M_TCPDO);
20180 	}
20181 }
20182 
20183 static void
20184 rack_hw_tls_change(struct tcpcb *tp, int chg)
20185 {
20186 	/* Update HW tls state */
20187 	struct tcp_rack *rack;
20188 
20189 	rack = (struct tcp_rack *)tp->t_fb_ptr;
20190 	if (chg)
20191 		rack->r_ctl.fsb.hw_tls = 1;
20192 	else
20193 		rack->r_ctl.fsb.hw_tls = 0;
20194 }
20195 
20196 static int
20197 rack_pru_options(struct tcpcb *tp, int flags)
20198 {
20199 	if (flags & PRUS_OOB)
20200 		return (EOPNOTSUPP);
20201 	return (0);
20202 }
20203 
20204 static struct tcp_function_block __tcp_rack = {
20205 	.tfb_tcp_block_name = __XSTRING(STACKNAME),
20206 	.tfb_tcp_output = rack_output,
20207 	.tfb_do_queued_segments = ctf_do_queued_segments,
20208 	.tfb_do_segment_nounlock = rack_do_segment_nounlock,
20209 	.tfb_tcp_do_segment = rack_do_segment,
20210 	.tfb_tcp_ctloutput = rack_ctloutput,
20211 	.tfb_tcp_fb_init = rack_init,
20212 	.tfb_tcp_fb_fini = rack_fini,
20213 	.tfb_tcp_timer_stop_all = rack_stopall,
20214 	.tfb_tcp_rexmit_tmr = rack_remxt_tmr,
20215 	.tfb_tcp_handoff_ok = rack_handoff_ok,
20216 	.tfb_tcp_mtu_chg = rack_mtu_change,
20217 	.tfb_pru_options = rack_pru_options,
20218 	.tfb_hwtls_change = rack_hw_tls_change,
20219 	.tfb_compute_pipe = rack_compute_pipe,
20220 	.tfb_flags = TCP_FUNC_OUTPUT_CANDROP,
20221 };
20222 
20223 /*
20224  * rack_ctloutput() must drop the inpcb lock before performing copyin on
20225  * socket option arguments.  When it re-acquires the lock after the copy, it
20226  * has to revalidate that the connection is still valid for the socket
20227  * option.
20228  */
20229 static int
20230 rack_set_sockopt(struct inpcb *inp, struct sockopt *sopt)
20231 {
20232 #ifdef INET6
20233 	struct ip6_hdr *ip6;
20234 #endif
20235 #ifdef INET
20236 	struct ip *ip;
20237 #endif
20238 	struct tcpcb *tp;
20239 	struct tcp_rack *rack;
20240 	uint64_t loptval;
20241 	int32_t error = 0, optval;
20242 
20243 	tp = intotcpcb(inp);
20244 	rack = (struct tcp_rack *)tp->t_fb_ptr;
20245 	if (rack == NULL) {
20246 		INP_WUNLOCK(inp);
20247 		return (EINVAL);
20248 	}
20249 #ifdef INET6
20250 	ip6 = (struct ip6_hdr *)rack->r_ctl.fsb.tcp_ip_hdr;
20251 #endif
20252 #ifdef INET
20253 	ip = (struct ip *)rack->r_ctl.fsb.tcp_ip_hdr;
20254 #endif
20255 
20256 	switch (sopt->sopt_level) {
20257 #ifdef INET6
20258 	case IPPROTO_IPV6:
20259 		MPASS(inp->inp_vflag & INP_IPV6PROTO);
20260 		switch (sopt->sopt_name) {
20261 		case IPV6_USE_MIN_MTU:
20262 			tcp6_use_min_mtu(tp);
20263 			break;
20264 		case IPV6_TCLASS:
20265 			/*
20266 			 * The DSCP codepoint has changed, update the fsb.
20267 			 */
20268 			ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
20269 			    (rack->rc_inp->inp_flow & IPV6_FLOWINFO_MASK);
20270 			break;
20271 		}
20272 		INP_WUNLOCK(inp);
20273 		return (0);
20274 #endif
20275 #ifdef INET
20276 	case IPPROTO_IP:
20277 		switch (sopt->sopt_name) {
20278 		case IP_TOS:
20279 			/*
20280 			 * The DSCP codepoint has changed, update the fsb.
20281 			 */
20282 			ip->ip_tos = rack->rc_inp->inp_ip_tos;
20283 			break;
20284 		case IP_TTL:
20285 			/*
20286 			 * The TTL has changed, update the fsb.
20287 			 */
20288 			ip->ip_ttl = rack->rc_inp->inp_ip_ttl;
20289 			break;
20290 		}
20291 		INP_WUNLOCK(inp);
20292 		return (0);
20293 #endif
20294 	}
20295 
20296 	switch (sopt->sopt_name) {
20297 	case TCP_RACK_TLP_REDUCE:		/*  URL:tlp_reduce */
20298 	/*  Pacing related ones */
20299 	case TCP_RACK_PACE_ALWAYS:		/*  URL:pace_always */
20300 	case TCP_BBR_RACK_INIT_RATE:		/*  URL:irate */
20301 	case TCP_BBR_IWINTSO:			/*  URL:tso_iwin */
20302 	case TCP_RACK_PACE_MAX_SEG:		/*  URL:pace_max_seg */
20303 	case TCP_RACK_FORCE_MSEG:		/*  URL:force_max_seg */
20304 	case TCP_RACK_PACE_RATE_CA:		/*  URL:pr_ca */
20305 	case TCP_RACK_PACE_RATE_SS:		/*  URL:pr_ss*/
20306 	case TCP_RACK_PACE_RATE_REC:		/*  URL:pr_rec */
20307 	case TCP_RACK_GP_INCREASE_CA:		/*  URL:gp_inc_ca */
20308 	case TCP_RACK_GP_INCREASE_SS:		/*  URL:gp_inc_ss */
20309 	case TCP_RACK_GP_INCREASE_REC:		/*  URL:gp_inc_rec */
20310 	case TCP_RACK_RR_CONF:			/*  URL:rrr_conf */
20311 	case TCP_BBR_HDWR_PACE:			/*  URL:hdwrpace */
20312 	case TCP_HDWR_RATE_CAP:			/*  URL:hdwrcap boolean */
20313 	case TCP_PACING_RATE_CAP:		/*  URL:cap  -- used by side-channel */
20314 	case TCP_HDWR_UP_ONLY:			/*  URL:uponly -- hardware pacing  boolean */
20315        /* End pacing related */
20316 	case TCP_FAST_RSM_HACK:			/*  URL:frsm_hack */
20317 	case TCP_DELACK:			/*  URL:delack (in base TCP i.e. tcp_hints along with cc etc ) */
20318 	case TCP_RACK_PRR_SENDALOT:		/*  URL:prr_sendalot */
20319 	case TCP_RACK_MIN_TO:			/*  URL:min_to */
20320 	case TCP_RACK_EARLY_SEG:		/*  URL:early_seg */
20321 	case TCP_RACK_REORD_THRESH:		/*  URL:reord_thresh */
20322 	case TCP_RACK_REORD_FADE:		/*  URL:reord_fade */
20323 	case TCP_RACK_TLP_THRESH:		/*  URL:tlp_thresh */
20324 	case TCP_RACK_PKT_DELAY:		/*  URL:pkt_delay */
20325 	case TCP_RACK_TLP_USE:			/*  URL:tlp_use */
20326 	case TCP_BBR_RACK_RTT_USE:		/*  URL:rttuse */
20327 	case TCP_BBR_USE_RACK_RR:		/*  URL:rackrr */
20328 	case TCP_RACK_DO_DETECTION:		/*  URL:detect */
20329 	case TCP_NO_PRR:			/*  URL:noprr */
20330 	case TCP_TIMELY_DYN_ADJ:      		/*  URL:dynamic */
20331 	case TCP_DATA_AFTER_CLOSE:		/*  no URL */
20332 	case TCP_RACK_NONRXT_CFG_RATE:		/*  URL:nonrxtcr */
20333 	case TCP_SHARED_CWND_ENABLE:		/*  URL:scwnd */
20334 	case TCP_RACK_MBUF_QUEUE:		/*  URL:mqueue */
20335 	case TCP_RACK_NO_PUSH_AT_MAX:		/*  URL:npush */
20336 	case TCP_RACK_PACE_TO_FILL:		/*  URL:fillcw */
20337 	case TCP_SHARED_CWND_TIME_LIMIT:	/*  URL:lscwnd */
20338 	case TCP_RACK_PROFILE:			/*  URL:profile */
20339 	case TCP_USE_CMP_ACKS:			/*  URL:cmpack */
20340 	case TCP_RACK_ABC_VAL:			/*  URL:labc */
20341 	case TCP_REC_ABC_VAL:			/*  URL:reclabc */
20342 	case TCP_RACK_MEASURE_CNT:		/*  URL:measurecnt */
20343 	case TCP_DEFER_OPTIONS:			/*  URL:defer */
20344 	case TCP_RACK_DSACK_OPT:		/*  URL:dsack */
20345 	case TCP_RACK_PACING_BETA:		/*  URL:pacing_beta */
20346 	case TCP_RACK_PACING_BETA_ECN:		/*  URL:pacing_beta_ecn */
20347 	case TCP_RACK_TIMER_SLOP:		/*  URL:timer_slop */
20348 	case TCP_RACK_ENABLE_HYSTART:		/*  URL:hystart */
20349 		break;
20350 	default:
20351 		/* Filter off all unknown options to the base stack */
20352 		return (tcp_default_ctloutput(inp, sopt));
20353 		break;
20354 	}
20355 	INP_WUNLOCK(inp);
20356 	if (sopt->sopt_name == TCP_PACING_RATE_CAP) {
20357 		error = sooptcopyin(sopt, &loptval, sizeof(loptval), sizeof(loptval));
20358 		/*
20359 		 * We truncate it down to 32 bits for the socket-option trace this
20360 		 * means rates > 34Gbps won't show right, but thats probably ok.
20361 		 */
20362 		optval = (uint32_t)loptval;
20363 	} else {
20364 		error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
20365 		/* Save it in 64 bit form too */
20366 		loptval = optval;
20367 	}
20368 	if (error)
20369 		return (error);
20370 	INP_WLOCK(inp);
20371 	if (inp->inp_flags & INP_DROPPED) {
20372 		INP_WUNLOCK(inp);
20373 		return (ECONNRESET);
20374 	}
20375 	if (tp->t_fb != &__tcp_rack) {
20376 		INP_WUNLOCK(inp);
20377 		return (ENOPROTOOPT);
20378 	}
20379 	if (rack->defer_options && (rack->gp_ready == 0) &&
20380 	    (sopt->sopt_name != TCP_DEFER_OPTIONS) &&
20381 	    (sopt->sopt_name != TCP_RACK_PACING_BETA) &&
20382 	    (sopt->sopt_name != TCP_RACK_PACING_BETA_ECN) &&
20383 	    (sopt->sopt_name != TCP_RACK_MEASURE_CNT)) {
20384 		/* Options are beind deferred */
20385 		if (rack_add_deferred_option(rack, sopt->sopt_name, loptval)) {
20386 			INP_WUNLOCK(inp);
20387 			return (0);
20388 		} else {
20389 			/* No memory to defer, fail */
20390 			INP_WUNLOCK(inp);
20391 			return (ENOMEM);
20392 		}
20393 	}
20394 	error = rack_process_option(tp, rack, sopt->sopt_name, optval, loptval);
20395 	INP_WUNLOCK(inp);
20396 	return (error);
20397 }
20398 
20399 static void
20400 rack_fill_info(struct tcpcb *tp, struct tcp_info *ti)
20401 {
20402 
20403 	INP_WLOCK_ASSERT(tptoinpcb(tp));
20404 	bzero(ti, sizeof(*ti));
20405 
20406 	ti->tcpi_state = tp->t_state;
20407 	if ((tp->t_flags & TF_REQ_TSTMP) && (tp->t_flags & TF_RCVD_TSTMP))
20408 		ti->tcpi_options |= TCPI_OPT_TIMESTAMPS;
20409 	if (tp->t_flags & TF_SACK_PERMIT)
20410 		ti->tcpi_options |= TCPI_OPT_SACK;
20411 	if ((tp->t_flags & TF_REQ_SCALE) && (tp->t_flags & TF_RCVD_SCALE)) {
20412 		ti->tcpi_options |= TCPI_OPT_WSCALE;
20413 		ti->tcpi_snd_wscale = tp->snd_scale;
20414 		ti->tcpi_rcv_wscale = tp->rcv_scale;
20415 	}
20416 	if (tp->t_flags2 & (TF2_ECN_PERMIT | TF2_ACE_PERMIT))
20417 		ti->tcpi_options |= TCPI_OPT_ECN;
20418 	if (tp->t_flags & TF_FASTOPEN)
20419 		ti->tcpi_options |= TCPI_OPT_TFO;
20420 	/* still kept in ticks is t_rcvtime */
20421 	ti->tcpi_last_data_recv = ((uint32_t)ticks - tp->t_rcvtime) * tick;
20422 	/* Since we hold everything in precise useconds this is easy */
20423 	ti->tcpi_rtt = tp->t_srtt;
20424 	ti->tcpi_rttvar = tp->t_rttvar;
20425 	ti->tcpi_rto = tp->t_rxtcur;
20426 	ti->tcpi_snd_ssthresh = tp->snd_ssthresh;
20427 	ti->tcpi_snd_cwnd = tp->snd_cwnd;
20428 	/*
20429 	 * FreeBSD-specific extension fields for tcp_info.
20430 	 */
20431 	ti->tcpi_rcv_space = tp->rcv_wnd;
20432 	ti->tcpi_rcv_nxt = tp->rcv_nxt;
20433 	ti->tcpi_snd_wnd = tp->snd_wnd;
20434 	ti->tcpi_snd_bwnd = 0;		/* Unused, kept for compat. */
20435 	ti->tcpi_snd_nxt = tp->snd_nxt;
20436 	ti->tcpi_snd_mss = tp->t_maxseg;
20437 	ti->tcpi_rcv_mss = tp->t_maxseg;
20438 	ti->tcpi_snd_rexmitpack = tp->t_sndrexmitpack;
20439 	ti->tcpi_rcv_ooopack = tp->t_rcvoopack;
20440 	ti->tcpi_snd_zerowin = tp->t_sndzerowin;
20441 #ifdef NETFLIX_STATS
20442 	ti->tcpi_total_tlp = tp->t_sndtlppack;
20443 	ti->tcpi_total_tlp_bytes = tp->t_sndtlpbyte;
20444 	memcpy(&ti->tcpi_rxsyninfo, &tp->t_rxsyninfo, sizeof(struct tcpsyninfo));
20445 #endif
20446 #ifdef TCP_OFFLOAD
20447 	if (tp->t_flags & TF_TOE) {
20448 		ti->tcpi_options |= TCPI_OPT_TOE;
20449 		tcp_offload_tcp_info(tp, ti);
20450 	}
20451 #endif
20452 }
20453 
20454 static int
20455 rack_get_sockopt(struct inpcb *inp, struct sockopt *sopt)
20456 {
20457 	struct tcpcb *tp;
20458 	struct tcp_rack *rack;
20459 	int32_t error, optval;
20460 	uint64_t val, loptval;
20461 	struct	tcp_info ti;
20462 	/*
20463 	 * Because all our options are either boolean or an int, we can just
20464 	 * pull everything into optval and then unlock and copy. If we ever
20465 	 * add a option that is not a int, then this will have quite an
20466 	 * impact to this routine.
20467 	 */
20468 	error = 0;
20469 	tp = intotcpcb(inp);
20470 	rack = (struct tcp_rack *)tp->t_fb_ptr;
20471 	if (rack == NULL) {
20472 		INP_WUNLOCK(inp);
20473 		return (EINVAL);
20474 	}
20475 	switch (sopt->sopt_name) {
20476 	case TCP_INFO:
20477 		/* First get the info filled */
20478 		rack_fill_info(tp, &ti);
20479 		/* Fix up the rtt related fields if needed */
20480 		INP_WUNLOCK(inp);
20481 		error = sooptcopyout(sopt, &ti, sizeof ti);
20482 		return (error);
20483 	/*
20484 	 * Beta is the congestion control value for NewReno that influences how
20485 	 * much of a backoff happens when loss is detected. It is normally set
20486 	 * to 50 for 50% i.e. the cwnd is reduced to 50% of its previous value
20487 	 * when you exit recovery.
20488 	 */
20489 	case TCP_RACK_PACING_BETA:
20490 		if (strcmp(tp->t_cc->name, CCALGONAME_NEWRENO) != 0)
20491 			error = EINVAL;
20492 		else if (rack->rc_pacing_cc_set == 0)
20493 			optval = rack->r_ctl.rc_saved_beta.beta;
20494 		else {
20495 			/*
20496 			 * Reach out into the CC data and report back what
20497 			 * I have previously set. Yeah it looks hackish but
20498 			 * we don't want to report the saved values.
20499 			 */
20500 			if (tp->t_ccv.cc_data)
20501 				optval = ((struct newreno *)tp->t_ccv.cc_data)->beta;
20502 			else
20503 				error = EINVAL;
20504 		}
20505 		break;
20506 		/*
20507 		 * Beta_ecn is the congestion control value for NewReno that influences how
20508 		 * much of a backoff happens when a ECN mark is detected. It is normally set
20509 		 * to 80 for 80% i.e. the cwnd is reduced by 20% of its previous value when
20510 		 * you exit recovery. Note that classic ECN has a beta of 50, it is only
20511 		 * ABE Ecn that uses this "less" value, but we do too with pacing :)
20512 		 */
20513 
20514 	case TCP_RACK_PACING_BETA_ECN:
20515 		if (strcmp(tp->t_cc->name, CCALGONAME_NEWRENO) != 0)
20516 			error = EINVAL;
20517 		else if (rack->rc_pacing_cc_set == 0)
20518 			optval = rack->r_ctl.rc_saved_beta.beta_ecn;
20519 		else {
20520 			/*
20521 			 * Reach out into the CC data and report back what
20522 			 * I have previously set. Yeah it looks hackish but
20523 			 * we don't want to report the saved values.
20524 			 */
20525 			if (tp->t_ccv.cc_data)
20526 				optval = ((struct newreno *)tp->t_ccv.cc_data)->beta_ecn;
20527 			else
20528 				error = EINVAL;
20529 		}
20530 		break;
20531 	case TCP_RACK_DSACK_OPT:
20532 		optval = 0;
20533 		if (rack->rc_rack_tmr_std_based) {
20534 			optval |= 1;
20535 		}
20536 		if (rack->rc_rack_use_dsack) {
20537 			optval |= 2;
20538 		}
20539 		break;
20540  	case TCP_RACK_ENABLE_HYSTART:
20541 	{
20542 		if (tp->t_ccv.flags & CCF_HYSTART_ALLOWED) {
20543 			optval = RACK_HYSTART_ON;
20544 			if (tp->t_ccv.flags & CCF_HYSTART_CAN_SH_CWND)
20545 				optval = RACK_HYSTART_ON_W_SC;
20546 			if (tp->t_ccv.flags & CCF_HYSTART_CONS_SSTH)
20547 				optval = RACK_HYSTART_ON_W_SC_C;
20548 		} else {
20549 			optval = RACK_HYSTART_OFF;
20550 		}
20551 	}
20552 	break;
20553 	case TCP_FAST_RSM_HACK:
20554 		optval = rack->fast_rsm_hack;
20555 		break;
20556 	case TCP_DEFER_OPTIONS:
20557 		optval = rack->defer_options;
20558 		break;
20559 	case TCP_RACK_MEASURE_CNT:
20560 		optval = rack->r_ctl.req_measurements;
20561 		break;
20562 	case TCP_REC_ABC_VAL:
20563 		optval = rack->r_use_labc_for_rec;
20564 		break;
20565 	case TCP_RACK_ABC_VAL:
20566 		optval = rack->rc_labc;
20567 		break;
20568 	case TCP_HDWR_UP_ONLY:
20569 		optval= rack->r_up_only;
20570 		break;
20571 	case TCP_PACING_RATE_CAP:
20572 		loptval = rack->r_ctl.bw_rate_cap;
20573 		break;
20574 	case TCP_RACK_PROFILE:
20575 		/* You cannot retrieve a profile, its write only */
20576 		error = EINVAL;
20577 		break;
20578 	case TCP_USE_CMP_ACKS:
20579 		optval = rack->r_use_cmp_ack;
20580 		break;
20581 	case TCP_RACK_PACE_TO_FILL:
20582 		optval = rack->rc_pace_to_cwnd;
20583 		if (optval && rack->r_fill_less_agg)
20584 			optval++;
20585 		break;
20586 	case TCP_RACK_NO_PUSH_AT_MAX:
20587 		optval = rack->r_ctl.rc_no_push_at_mrtt;
20588 		break;
20589 	case TCP_SHARED_CWND_ENABLE:
20590 		optval = rack->rack_enable_scwnd;
20591 		break;
20592 	case TCP_RACK_NONRXT_CFG_RATE:
20593 		optval = rack->rack_rec_nonrxt_use_cr;
20594 		break;
20595 	case TCP_NO_PRR:
20596 		if (rack->rack_no_prr  == 1)
20597 			optval = 1;
20598 		else if (rack->no_prr_addback == 1)
20599 			optval = 2;
20600 		else
20601 			optval = 0;
20602 		break;
20603 	case TCP_RACK_DO_DETECTION:
20604 		optval = rack->do_detection;
20605 		break;
20606 	case TCP_RACK_MBUF_QUEUE:
20607 		/* Now do we use the LRO mbuf-queue feature */
20608 		optval = rack->r_mbuf_queue;
20609 		break;
20610 	case TCP_TIMELY_DYN_ADJ:
20611 		optval = rack->rc_gp_dyn_mul;
20612 		break;
20613 	case TCP_BBR_IWINTSO:
20614 		optval = rack->rc_init_win;
20615 		break;
20616 	case TCP_RACK_TLP_REDUCE:
20617 		/* RACK TLP cwnd reduction (bool) */
20618 		optval = rack->r_ctl.rc_tlp_cwnd_reduce;
20619 		break;
20620 	case TCP_BBR_RACK_INIT_RATE:
20621 		val = rack->r_ctl.init_rate;
20622 		/* convert to kbits per sec */
20623 		val *= 8;
20624 		val /= 1000;
20625 		optval = (uint32_t)val;
20626 		break;
20627 	case TCP_RACK_FORCE_MSEG:
20628 		optval = rack->rc_force_max_seg;
20629 		break;
20630 	case TCP_RACK_PACE_MAX_SEG:
20631 		/* Max segments in a pace */
20632 		optval = rack->rc_user_set_max_segs;
20633 		break;
20634 	case TCP_RACK_PACE_ALWAYS:
20635 		/* Use the always pace method */
20636 		optval = rack->rc_always_pace;
20637 		break;
20638 	case TCP_RACK_PRR_SENDALOT:
20639 		/* Allow PRR to send more than one seg */
20640 		optval = rack->r_ctl.rc_prr_sendalot;
20641 		break;
20642 	case TCP_RACK_MIN_TO:
20643 		/* Minimum time between rack t-o's in ms */
20644 		optval = rack->r_ctl.rc_min_to;
20645 		break;
20646 	case TCP_RACK_EARLY_SEG:
20647 		/* If early recovery max segments */
20648 		optval = rack->r_ctl.rc_early_recovery_segs;
20649 		break;
20650 	case TCP_RACK_REORD_THRESH:
20651 		/* RACK reorder threshold (shift amount) */
20652 		optval = rack->r_ctl.rc_reorder_shift;
20653 		break;
20654 	case TCP_RACK_REORD_FADE:
20655 		/* Does reordering fade after ms time */
20656 		optval = rack->r_ctl.rc_reorder_fade;
20657 		break;
20658 	case TCP_BBR_USE_RACK_RR:
20659 		/* Do we use the rack cheat for rxt */
20660 		optval = rack->use_rack_rr;
20661 		break;
20662 	case TCP_RACK_RR_CONF:
20663 		optval = rack->r_rr_config;
20664 		break;
20665 	case TCP_HDWR_RATE_CAP:
20666 		optval = rack->r_rack_hw_rate_caps;
20667 		break;
20668 	case TCP_BBR_HDWR_PACE:
20669 		optval = rack->rack_hdw_pace_ena;
20670 		break;
20671 	case TCP_RACK_TLP_THRESH:
20672 		/* RACK TLP theshold i.e. srtt+(srtt/N) */
20673 		optval = rack->r_ctl.rc_tlp_threshold;
20674 		break;
20675 	case TCP_RACK_PKT_DELAY:
20676 		/* RACK added ms i.e. rack-rtt + reord + N */
20677 		optval = rack->r_ctl.rc_pkt_delay;
20678 		break;
20679 	case TCP_RACK_TLP_USE:
20680 		optval = rack->rack_tlp_threshold_use;
20681 		break;
20682 	case TCP_RACK_PACE_RATE_CA:
20683 		optval = rack->r_ctl.rc_fixed_pacing_rate_ca;
20684 		break;
20685 	case TCP_RACK_PACE_RATE_SS:
20686 		optval = rack->r_ctl.rc_fixed_pacing_rate_ss;
20687 		break;
20688 	case TCP_RACK_PACE_RATE_REC:
20689 		optval = rack->r_ctl.rc_fixed_pacing_rate_rec;
20690 		break;
20691 	case TCP_RACK_GP_INCREASE_SS:
20692 		optval = rack->r_ctl.rack_per_of_gp_ca;
20693 		break;
20694 	case TCP_RACK_GP_INCREASE_CA:
20695 		optval = rack->r_ctl.rack_per_of_gp_ss;
20696 		break;
20697 	case TCP_BBR_RACK_RTT_USE:
20698 		optval = rack->r_ctl.rc_rate_sample_method;
20699 		break;
20700 	case TCP_DELACK:
20701 		optval = tp->t_delayed_ack;
20702 		break;
20703 	case TCP_DATA_AFTER_CLOSE:
20704 		optval = rack->rc_allow_data_af_clo;
20705 		break;
20706 	case TCP_SHARED_CWND_TIME_LIMIT:
20707 		optval = rack->r_limit_scw;
20708 		break;
20709 	case TCP_RACK_TIMER_SLOP:
20710 		optval = rack->r_ctl.timer_slop;
20711 		break;
20712 	default:
20713 		return (tcp_default_ctloutput(inp, sopt));
20714 		break;
20715 	}
20716 	INP_WUNLOCK(inp);
20717 	if (error == 0) {
20718 		if (TCP_PACING_RATE_CAP)
20719 			error = sooptcopyout(sopt, &loptval, sizeof loptval);
20720 		else
20721 			error = sooptcopyout(sopt, &optval, sizeof optval);
20722 	}
20723 	return (error);
20724 }
20725 
20726 static int
20727 rack_ctloutput(struct inpcb *inp, struct sockopt *sopt)
20728 {
20729 	if (sopt->sopt_dir == SOPT_SET) {
20730 		return (rack_set_sockopt(inp, sopt));
20731 	} else if (sopt->sopt_dir == SOPT_GET) {
20732 		return (rack_get_sockopt(inp, sopt));
20733 	} else {
20734 		panic("%s: sopt_dir $%d", __func__, sopt->sopt_dir);
20735 	}
20736 }
20737 
20738 static const char *rack_stack_names[] = {
20739 	__XSTRING(STACKNAME),
20740 #ifdef STACKALIAS
20741 	__XSTRING(STACKALIAS),
20742 #endif
20743 };
20744 
20745 static int
20746 rack_ctor(void *mem, int32_t size, void *arg, int32_t how)
20747 {
20748 	memset(mem, 0, size);
20749 	return (0);
20750 }
20751 
20752 static void
20753 rack_dtor(void *mem, int32_t size, void *arg)
20754 {
20755 
20756 }
20757 
20758 static bool rack_mod_inited = false;
20759 
20760 static int
20761 tcp_addrack(module_t mod, int32_t type, void *data)
20762 {
20763 	int32_t err = 0;
20764 	int num_stacks;
20765 
20766 	switch (type) {
20767 	case MOD_LOAD:
20768 		rack_zone = uma_zcreate(__XSTRING(MODNAME) "_map",
20769 		    sizeof(struct rack_sendmap),
20770 		    rack_ctor, rack_dtor, NULL, NULL, UMA_ALIGN_PTR, 0);
20771 
20772 		rack_pcb_zone = uma_zcreate(__XSTRING(MODNAME) "_pcb",
20773 		    sizeof(struct tcp_rack),
20774 		    rack_ctor, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
20775 
20776 		sysctl_ctx_init(&rack_sysctl_ctx);
20777 		rack_sysctl_root = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
20778 		    SYSCTL_STATIC_CHILDREN(_net_inet_tcp),
20779 		    OID_AUTO,
20780 #ifdef STACKALIAS
20781 		    __XSTRING(STACKALIAS),
20782 #else
20783 		    __XSTRING(STACKNAME),
20784 #endif
20785 		    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
20786 		    "");
20787 		if (rack_sysctl_root == NULL) {
20788 			printf("Failed to add sysctl node\n");
20789 			err = EFAULT;
20790 			goto free_uma;
20791 		}
20792 		rack_init_sysctls();
20793 		num_stacks = nitems(rack_stack_names);
20794 		err = register_tcp_functions_as_names(&__tcp_rack, M_WAITOK,
20795 		    rack_stack_names, &num_stacks);
20796 		if (err) {
20797 			printf("Failed to register %s stack name for "
20798 			    "%s module\n", rack_stack_names[num_stacks],
20799 			    __XSTRING(MODNAME));
20800 			sysctl_ctx_free(&rack_sysctl_ctx);
20801 free_uma:
20802 			uma_zdestroy(rack_zone);
20803 			uma_zdestroy(rack_pcb_zone);
20804 			rack_counter_destroy();
20805 			printf("Failed to register rack module -- err:%d\n", err);
20806 			return (err);
20807 		}
20808 		tcp_lro_reg_mbufq();
20809 		rack_mod_inited = true;
20810 		break;
20811 	case MOD_QUIESCE:
20812 		err = deregister_tcp_functions(&__tcp_rack, true, false);
20813 		break;
20814 	case MOD_UNLOAD:
20815 		err = deregister_tcp_functions(&__tcp_rack, false, true);
20816 		if (err == EBUSY)
20817 			break;
20818 		if (rack_mod_inited) {
20819 			uma_zdestroy(rack_zone);
20820 			uma_zdestroy(rack_pcb_zone);
20821 			sysctl_ctx_free(&rack_sysctl_ctx);
20822 			rack_counter_destroy();
20823 			rack_mod_inited = false;
20824 		}
20825 		tcp_lro_dereg_mbufq();
20826 		err = 0;
20827 		break;
20828 	default:
20829 		return (EOPNOTSUPP);
20830 	}
20831 	return (err);
20832 }
20833 
20834 static moduledata_t tcp_rack = {
20835 	.name = __XSTRING(MODNAME),
20836 	.evhand = tcp_addrack,
20837 	.priv = 0
20838 };
20839 
20840 MODULE_VERSION(MODNAME, 1);
20841 DECLARE_MODULE(MODNAME, tcp_rack, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
20842 MODULE_DEPEND(MODNAME, tcphpts, 1, 1, 1);
20843 
20844 #endif /* #if !defined(INET) && !defined(INET6) */
20845