xref: /freebsd/sys/netinet/tcp_stacks/rack.c (revision d485c77f203fb0f4cdc08dea5ff81631b51d8809) 
1 /*-
2  * Copyright (c) 2016-2020 Netflix, Inc.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  *
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include "opt_inet.h"
31 #include "opt_inet6.h"
32 #include "opt_ipsec.h"
33 #include "opt_tcpdebug.h"
34 #include "opt_ratelimit.h"
35 #include <sys/param.h>
36 #include <sys/arb.h>
37 #include <sys/module.h>
38 #include <sys/kernel.h>
39 #ifdef TCP_HHOOK
40 #include <sys/hhook.h>
41 #endif
42 #include <sys/lock.h>
43 #include <sys/malloc.h>
44 #include <sys/lock.h>
45 #include <sys/mutex.h>
46 #include <sys/mbuf.h>
47 #include <sys/proc.h>		/* for proc0 declaration */
48 #include <sys/socket.h>
49 #include <sys/socketvar.h>
50 #include <sys/sysctl.h>
51 #include <sys/systm.h>
52 #ifdef STATS
53 #include <sys/qmath.h>
54 #include <sys/tree.h>
55 #include <sys/stats.h> /* Must come after qmath.h and tree.h */
56 #else
57 #include <sys/tree.h>
58 #endif
59 #include <sys/refcount.h>
60 #include <sys/queue.h>
61 #include <sys/tim_filter.h>
62 #include <sys/smp.h>
63 #include <sys/kthread.h>
64 #include <sys/kern_prefetch.h>
65 #include <sys/protosw.h>
66 
67 #include <vm/uma.h>
68 
69 #include <net/route.h>
70 #include <net/route/nhop.h>
71 #include <net/vnet.h>
72 
73 #define TCPSTATES		/* for logging */
74 
75 #include <netinet/in.h>
76 #include <netinet/in_kdtrace.h>
77 #include <netinet/in_pcb.h>
78 #include <netinet/ip.h>
79 #include <netinet/ip_icmp.h>	/* required for icmp_var.h */
80 #include <netinet/icmp_var.h>	/* for ICMP_BANDLIM */
81 #include <netinet/ip_var.h>
82 #include <netinet/ip6.h>
83 #include <netinet6/in6_pcb.h>
84 #include <netinet6/ip6_var.h>
85 #include <netinet/tcp.h>
86 #define	TCPOUTFLAGS
87 #include <netinet/tcp_fsm.h>
88 #include <netinet/tcp_log_buf.h>
89 #include <netinet/tcp_seq.h>
90 #include <netinet/tcp_timer.h>
91 #include <netinet/tcp_var.h>
92 #include <netinet/tcp_hpts.h>
93 #include <netinet/tcp_ratelimit.h>
94 #include <netinet/tcpip.h>
95 #include <netinet/cc/cc.h>
96 #include <netinet/tcp_fastopen.h>
97 #include <netinet/tcp_lro.h>
98 #ifdef NETFLIX_SHARED_CWND
99 #include <netinet/tcp_shared_cwnd.h>
100 #endif
101 #ifdef TCPDEBUG
102 #include <netinet/tcp_debug.h>
103 #endif				/* TCPDEBUG */
104 #ifdef TCP_OFFLOAD
105 #include <netinet/tcp_offload.h>
106 #endif
107 #ifdef INET6
108 #include <netinet6/tcp6_var.h>
109 #endif
110 
111 #include <netipsec/ipsec_support.h>
112 
113 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
114 #include <netipsec/ipsec.h>
115 #include <netipsec/ipsec6.h>
116 #endif				/* IPSEC */
117 
118 #include <netinet/udp.h>
119 #include <netinet/udp_var.h>
120 #include <machine/in_cksum.h>
121 
122 #ifdef MAC
123 #include <security/mac/mac_framework.h>
124 #endif
125 #include "sack_filter.h"
126 #include "tcp_rack.h"
127 #include "rack_bbr_common.h"
128 
129 uma_zone_t rack_zone;
130 uma_zone_t rack_pcb_zone;
131 
132 #ifndef TICKS2SBT
133 #define	TICKS2SBT(__t)	(tick_sbt * ((sbintime_t)(__t)))
134 #endif
135 
136 struct sysctl_ctx_list rack_sysctl_ctx;
137 struct sysctl_oid *rack_sysctl_root;
138 
139 #define CUM_ACKED 1
140 #define SACKED 2
141 
142 /*
143  * The RACK module incorporates a number of
144  * TCP ideas that have been put out into the IETF
145  * over the last few years:
146  * - Matt Mathis's Rate Halving which slowly drops
147  *    the congestion window so that the ack clock can
148  *    be maintained during a recovery.
149  * - Yuchung Cheng's RACK TCP (for which its named) that
150  *    will stop us using the number of dup acks and instead
151  *    use time as the gage of when we retransmit.
152  * - Reorder Detection of RFC4737 and the Tail-Loss probe draft
153  *    of Dukkipati et.al.
154  * RACK depends on SACK, so if an endpoint arrives that
155  * cannot do SACK the state machine below will shuttle the
156  * connection back to using the "default" TCP stack that is
157  * in FreeBSD.
158  *
159  * To implement RACK the original TCP stack was first decomposed
160  * into a functional state machine with individual states
161  * for each of the possible TCP connection states. The do_segement
162  * functions role in life is to mandate the connection supports SACK
163  * initially and then assure that the RACK state matches the conenction
164  * state before calling the states do_segment function. Each
165  * state is simplified due to the fact that the original do_segment
166  * has been decomposed and we *know* what state we are in (no
167  * switches on the state) and all tests for SACK are gone. This
168  * greatly simplifies what each state does.
169  *
170  * TCP output is also over-written with a new version since it
171  * must maintain the new rack scoreboard.
172  *
173  */
174 static int32_t rack_tlp_thresh = 1;
175 static int32_t rack_tlp_limit = 2;	/* No more than 2 TLPs w-out new data */
176 static int32_t rack_tlp_use_greater = 1;
177 static int32_t rack_reorder_thresh = 2;
178 static int32_t rack_reorder_fade = 60000;	/* 0 - never fade, def 60,000
179 						 * - 60 seconds */
180 /* Attack threshold detections */
181 static uint32_t rack_highest_sack_thresh_seen = 0;
182 static uint32_t rack_highest_move_thresh_seen = 0;
183 
184 static int32_t rack_pkt_delay = 1;
185 static int32_t rack_early_recovery = 1;
186 static int32_t rack_send_a_lot_in_prr = 1;
187 static int32_t rack_min_to = 1;	/* Number of ms minimum timeout */
188 static int32_t rack_verbose_logging = 0;
189 static int32_t rack_ignore_data_after_close = 1;
190 static int32_t rack_enable_shared_cwnd = 0;
191 static int32_t rack_limits_scwnd = 1;
192 static int32_t rack_enable_mqueue_for_nonpaced = 0;
193 static int32_t rack_disable_prr = 0;
194 static int32_t use_rack_rr = 1;
195 static int32_t rack_non_rxt_use_cr = 0; /* does a non-rxt in recovery use the configured rate (ss/ca)? */
196 static int32_t rack_persist_min = 250;	/* 250ms */
197 static int32_t rack_persist_max = 2000;	/* 2 Second */
198 static int32_t rack_sack_not_required = 0;	/* set to one to allow non-sack to use rack */
199 static int32_t rack_default_init_window = 0; 	/* Use system default */
200 static int32_t rack_limit_time_with_srtt = 0;
201 static int32_t rack_hw_pace_adjust = 0;
202 /*
203  * Currently regular tcp has a rto_min of 30ms
204  * the backoff goes 12 times so that ends up
205  * being a total of 122.850 seconds before a
206  * connection is killed.
207  */
208 static uint32_t rack_def_data_window = 20;
209 static uint32_t rack_goal_bdp = 2;
210 static uint32_t rack_min_srtts = 1;
211 static uint32_t rack_min_measure_usec = 0;
212 static int32_t rack_tlp_min = 10;
213 static int32_t rack_rto_min = 30;	/* 30ms same as main freebsd */
214 static int32_t rack_rto_max = 4000;	/* 4 seconds */
215 static const int32_t rack_free_cache = 2;
216 static int32_t rack_hptsi_segments = 40;
217 static int32_t rack_rate_sample_method = USE_RTT_LOW;
218 static int32_t rack_pace_every_seg = 0;
219 static int32_t rack_delayed_ack_time = 200;	/* 200ms */
220 static int32_t rack_slot_reduction = 4;
221 static int32_t rack_wma_divisor = 8;		/* For WMA calculation */
222 static int32_t rack_cwnd_block_ends_measure = 0;
223 static int32_t rack_rwnd_block_ends_measure = 0;
224 
225 static int32_t rack_lower_cwnd_at_tlp = 0;
226 static int32_t rack_use_proportional_reduce = 0;
227 static int32_t rack_proportional_rate = 10;
228 static int32_t rack_tlp_max_resend = 2;
229 static int32_t rack_limited_retran = 0;
230 static int32_t rack_always_send_oldest = 0;
231 static int32_t rack_tlp_threshold_use = TLP_USE_TWO_ONE;
232 
233 static uint16_t rack_per_of_gp_ss = 250;	/* 250 % slow-start */
234 static uint16_t rack_per_of_gp_ca = 200;	/* 200 % congestion-avoidance */
235 static uint16_t rack_per_of_gp_rec = 200;	/* 200 % of bw */
236 
237 /* Probertt */
238 static uint16_t rack_per_of_gp_probertt = 60;	/* 60% of bw */
239 static uint16_t rack_per_of_gp_lowthresh = 40;	/* 40% is bottom */
240 static uint16_t rack_per_of_gp_probertt_reduce = 10; /* 10% reduction */
241 static uint16_t rack_atexit_prtt_hbp = 130;	/* Clamp to 130% on exit prtt if highly buffered path */
242 static uint16_t rack_atexit_prtt = 130;	/* Clamp to 100% on exit prtt if non highly buffered path */
243 
244 static uint32_t rack_max_drain_wait = 2;	/* How man gp srtt's before we give up draining */
245 static uint32_t rack_must_drain = 1;		/* How many GP srtt's we *must* wait */
246 static uint32_t rack_probertt_use_min_rtt_entry = 1;	/* Use the min to calculate the goal else gp_srtt */
247 static uint32_t rack_probertt_use_min_rtt_exit = 0;
248 static uint32_t rack_probe_rtt_sets_cwnd = 0;
249 static uint32_t rack_probe_rtt_safety_val = 2000000;	/* No more than 2 sec in probe-rtt */
250 static uint32_t rack_time_between_probertt = 9600000;	/* 9.6 sec in us */
251 static uint32_t rack_probertt_gpsrtt_cnt_mul = 0;	/* How many srtt periods does probe-rtt last top fraction */
252 static uint32_t rack_probertt_gpsrtt_cnt_div = 0;	/* How many srtt periods does probe-rtt last bottom fraction  */
253 static uint32_t rack_min_probertt_hold = 200000;	/* Equal to delayed ack time */
254 static uint32_t rack_probertt_filter_life = 10000000;
255 static uint32_t rack_probertt_lower_within = 10;
256 static uint32_t rack_min_rtt_movement = 250;	/* Must move at least 250 useconds to count as a lowering */
257 static int32_t rack_pace_one_seg = 0;		/* Shall we pace for less than 1.4Meg 1MSS at a time */
258 static int32_t rack_probertt_clear_is = 1;
259 static int32_t rack_max_drain_hbp = 1;		/* Extra drain times gpsrtt for highly buffered paths */
260 static int32_t rack_hbp_thresh = 3;		/* what is the divisor max_rtt/min_rtt to decided a hbp */
261 
262 /* Part of pacing */
263 static int32_t rack_max_per_above = 30;		/* When we go to increment stop if above 100+this% */
264 
265 /* Timely information */
266 /* Combine these two gives the range of 'no change' to bw */
267 /* ie the up/down provide the upper and lower bound  */
268 static int32_t rack_gp_per_bw_mul_up = 2;	/* 2% */
269 static int32_t rack_gp_per_bw_mul_down = 4;	/* 4% */
270 static int32_t rack_gp_rtt_maxmul = 3;		/* 3 x maxmin */
271 static int32_t rack_gp_rtt_minmul = 1;		/* minrtt + (minrtt/mindiv) is lower rtt */
272 static int32_t rack_gp_rtt_mindiv = 4;		/* minrtt + (minrtt * minmul/mindiv) is lower rtt */
273 static int32_t rack_gp_decrease_per = 20;	/* 20% decrease in multipler */
274 static int32_t rack_gp_increase_per = 2;	/* 2% increase in multipler */
275 static int32_t rack_per_lower_bound = 50;	/* Don't allow to drop below this multiplier */
276 static int32_t rack_per_upper_bound_ss = 0;	/* Don't allow SS to grow above this */
277 static int32_t rack_per_upper_bound_ca = 0;	/* Don't allow CA to grow above this */
278 static int32_t rack_do_dyn_mul = 0;		/* Are the rack gp multipliers dynamic */
279 static int32_t rack_gp_no_rec_chg = 1;		/* Prohibit recovery from reducing it's multiplier */
280 static int32_t rack_timely_dec_clear = 6;	/* Do we clear decrement count at a value (6)? */
281 static int32_t rack_timely_max_push_rise = 3;	/* One round of pushing */
282 static int32_t rack_timely_max_push_drop = 3;	/* Three round of pushing */
283 static int32_t rack_timely_min_segs = 4;	/* 4 segment minimum */
284 static int32_t rack_use_max_for_nobackoff = 0;
285 static int32_t rack_timely_int_timely_only = 0;	/* do interim timely's only use the timely algo (no b/w changes)? */
286 static int32_t rack_timely_no_stopping = 0;
287 static int32_t rack_down_raise_thresh = 100;
288 static int32_t rack_req_segs = 1;
289 
290 /* Weird delayed ack mode */
291 static int32_t rack_use_imac_dack = 0;
292 /* Rack specific counters */
293 counter_u64_t rack_badfr;
294 counter_u64_t rack_badfr_bytes;
295 counter_u64_t rack_rtm_prr_retran;
296 counter_u64_t rack_rtm_prr_newdata;
297 counter_u64_t rack_timestamp_mismatch;
298 counter_u64_t rack_reorder_seen;
299 counter_u64_t rack_paced_segments;
300 counter_u64_t rack_unpaced_segments;
301 counter_u64_t rack_calc_zero;
302 counter_u64_t rack_calc_nonzero;
303 counter_u64_t rack_saw_enobuf;
304 counter_u64_t rack_saw_enetunreach;
305 counter_u64_t rack_per_timer_hole;
306 
307 /* Tail loss probe counters */
308 counter_u64_t rack_tlp_tot;
309 counter_u64_t rack_tlp_newdata;
310 counter_u64_t rack_tlp_retran;
311 counter_u64_t rack_tlp_retran_bytes;
312 counter_u64_t rack_tlp_retran_fail;
313 counter_u64_t rack_to_tot;
314 counter_u64_t rack_to_arm_rack;
315 counter_u64_t rack_to_arm_tlp;
316 counter_u64_t rack_to_alloc;
317 counter_u64_t rack_to_alloc_hard;
318 counter_u64_t rack_to_alloc_emerg;
319 counter_u64_t rack_to_alloc_limited;
320 counter_u64_t rack_alloc_limited_conns;
321 counter_u64_t rack_split_limited;
322 
323 counter_u64_t rack_sack_proc_all;
324 counter_u64_t rack_sack_proc_short;
325 counter_u64_t rack_sack_proc_restart;
326 counter_u64_t rack_sack_attacks_detected;
327 counter_u64_t rack_sack_attacks_reversed;
328 counter_u64_t rack_sack_used_next_merge;
329 counter_u64_t rack_sack_splits;
330 counter_u64_t rack_sack_used_prev_merge;
331 counter_u64_t rack_sack_skipped_acked;
332 counter_u64_t rack_ack_total;
333 counter_u64_t rack_express_sack;
334 counter_u64_t rack_sack_total;
335 counter_u64_t rack_move_none;
336 counter_u64_t rack_move_some;
337 
338 counter_u64_t rack_used_tlpmethod;
339 counter_u64_t rack_used_tlpmethod2;
340 counter_u64_t rack_enter_tlp_calc;
341 counter_u64_t rack_input_idle_reduces;
342 counter_u64_t rack_collapsed_win;
343 counter_u64_t rack_tlp_does_nada;
344 counter_u64_t rack_try_scwnd;
345 
346 /* Temp CPU counters */
347 counter_u64_t rack_find_high;
348 
349 counter_u64_t rack_progress_drops;
350 counter_u64_t rack_out_size[TCP_MSS_ACCT_SIZE];
351 counter_u64_t rack_opts_arry[RACK_OPTS_SIZE];
352 
353 static void
354 rack_log_progress_event(struct tcp_rack *rack, struct tcpcb *tp, uint32_t tick,  int event, int line);
355 
356 static int
357 rack_process_ack(struct mbuf *m, struct tcphdr *th,
358     struct socket *so, struct tcpcb *tp, struct tcpopt *to,
359     uint32_t tiwin, int32_t tlen, int32_t * ofia, int32_t thflags, int32_t * ret_val);
360 static int
361 rack_process_data(struct mbuf *m, struct tcphdr *th,
362     struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
363     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt);
364 static void
365 rack_ack_received(struct tcpcb *tp, struct tcp_rack *rack,
366     struct tcphdr *th, uint16_t nsegs, uint16_t type, int32_t recovery);
367 static struct rack_sendmap *rack_alloc(struct tcp_rack *rack);
368 static struct rack_sendmap *rack_alloc_limit(struct tcp_rack *rack,
369     uint8_t limit_type);
370 static struct rack_sendmap *
371 rack_check_recovery_mode(struct tcpcb *tp,
372     uint32_t tsused);
373 static void
374 rack_cong_signal(struct tcpcb *tp, struct tcphdr *th,
375     uint32_t type);
376 static void rack_counter_destroy(void);
377 static int
378 rack_ctloutput(struct socket *so, struct sockopt *sopt,
379     struct inpcb *inp, struct tcpcb *tp);
380 static int32_t rack_ctor(void *mem, int32_t size, void *arg, int32_t how);
381 static void
382 rack_set_pace_segments(struct tcpcb *tp, struct tcp_rack *rack, uint32_t line);
383 static void
384 rack_do_segment(struct mbuf *m, struct tcphdr *th,
385     struct socket *so, struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
386     uint8_t iptos);
387 static void rack_dtor(void *mem, int32_t size, void *arg);
388 static void
389 rack_earlier_retran(struct tcpcb *tp, struct rack_sendmap *rsm,
390     uint32_t t, uint32_t cts);
391 static void
392 rack_log_alt_to_to_cancel(struct tcp_rack *rack,
393     uint32_t flex1, uint32_t flex2,
394     uint32_t flex3, uint32_t flex4,
395     uint32_t flex5, uint32_t flex6,
396     uint16_t flex7, uint8_t mod);
397 static void
398 rack_log_pacing_delay_calc(struct tcp_rack *rack, uint32_t len, uint32_t slot,
399    uint64_t bw_est, uint64_t bw, uint64_t len_time, int method, int line, struct rack_sendmap *rsm);
400 static struct rack_sendmap *
401 rack_find_high_nonack(struct tcp_rack *rack,
402     struct rack_sendmap *rsm);
403 static struct rack_sendmap *rack_find_lowest_rsm(struct tcp_rack *rack);
404 static void rack_free(struct tcp_rack *rack, struct rack_sendmap *rsm);
405 static void rack_fini(struct tcpcb *tp, int32_t tcb_is_purged);
406 static int
407 rack_get_sockopt(struct socket *so, struct sockopt *sopt,
408     struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack);
409 static void
410 rack_do_goodput_measurement(struct tcpcb *tp, struct tcp_rack *rack,
411 			    tcp_seq th_ack, int line);
412 static uint32_t
413 rack_get_pacing_len(struct tcp_rack *rack, uint64_t bw, uint32_t mss);
414 static int32_t rack_handoff_ok(struct tcpcb *tp);
415 static int32_t rack_init(struct tcpcb *tp);
416 static void rack_init_sysctls(void);
417 static void
418 rack_log_ack(struct tcpcb *tp, struct tcpopt *to,
419     struct tcphdr *th);
420 static void
421 rack_log_output(struct tcpcb *tp, struct tcpopt *to, int32_t len,
422     uint32_t seq_out, uint8_t th_flags, int32_t err, uint32_t ts,
423     uint8_t pass, struct rack_sendmap *hintrsm, uint32_t us_cts);
424 static void
425 rack_log_sack_passed(struct tcpcb *tp, struct tcp_rack *rack,
426     struct rack_sendmap *rsm);
427 static void rack_log_to_event(struct tcp_rack *rack, int32_t to_num, struct rack_sendmap *rsm);
428 static int32_t rack_output(struct tcpcb *tp);
429 
430 static uint32_t
431 rack_proc_sack_blk(struct tcpcb *tp, struct tcp_rack *rack,
432     struct sackblk *sack, struct tcpopt *to, struct rack_sendmap **prsm,
433     uint32_t cts, int *moved_two);
434 static void rack_post_recovery(struct tcpcb *tp, struct tcphdr *th);
435 static void rack_remxt_tmr(struct tcpcb *tp);
436 static int
437 rack_set_sockopt(struct socket *so, struct sockopt *sopt,
438     struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack);
439 static void rack_set_state(struct tcpcb *tp, struct tcp_rack *rack);
440 static int32_t rack_stopall(struct tcpcb *tp);
441 static void
442 rack_timer_activate(struct tcpcb *tp, uint32_t timer_type,
443     uint32_t delta);
444 static int32_t rack_timer_active(struct tcpcb *tp, uint32_t timer_type);
445 static void rack_timer_cancel(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int line);
446 static void rack_timer_stop(struct tcpcb *tp, uint32_t timer_type);
447 static uint32_t
448 rack_update_entry(struct tcpcb *tp, struct tcp_rack *rack,
449     struct rack_sendmap *rsm, uint32_t ts, int32_t * lenp);
450 static void
451 rack_update_rsm(struct tcpcb *tp, struct tcp_rack *rack,
452     struct rack_sendmap *rsm, uint32_t ts);
453 static int
454 rack_update_rtt(struct tcpcb *tp, struct tcp_rack *rack,
455     struct rack_sendmap *rsm, struct tcpopt *to, uint32_t cts, int32_t ack_type, tcp_seq th_ack);
456 static int32_t tcp_addrack(module_t mod, int32_t type, void *data);
457 static int
458 rack_do_close_wait(struct mbuf *m, struct tcphdr *th,
459     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
460     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
461 static int
462 rack_do_closing(struct mbuf *m, struct tcphdr *th,
463     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
464     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
465 static int
466 rack_do_established(struct mbuf *m, struct tcphdr *th,
467     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
468     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
469 static int
470 rack_do_fastnewdata(struct mbuf *m, struct tcphdr *th,
471     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
472     int32_t tlen, uint32_t tiwin, int32_t nxt_pkt, uint8_t iptos);
473 static int
474 rack_do_fin_wait_1(struct mbuf *m, struct tcphdr *th,
475     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
476     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
477 static int
478 rack_do_fin_wait_2(struct mbuf *m, struct tcphdr *th,
479     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
480     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
481 static int
482 rack_do_lastack(struct mbuf *m, struct tcphdr *th,
483     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
484     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
485 static int
486 rack_do_syn_recv(struct mbuf *m, struct tcphdr *th,
487     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
488     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
489 static int
490 rack_do_syn_sent(struct mbuf *m, struct tcphdr *th,
491     struct socket *so, struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen,
492     int32_t tlen, uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos);
493 struct rack_sendmap *
494 tcp_rack_output(struct tcpcb *tp, struct tcp_rack *rack,
495     uint32_t tsused);
496 static void tcp_rack_xmit_timer(struct tcp_rack *rack, int32_t rtt,
497     uint32_t len, uint32_t us_tim, int confidence, struct rack_sendmap *rsm, uint16_t rtrcnt);
498 static void
499      tcp_rack_partialack(struct tcpcb *tp, struct tcphdr *th);
500 
501 int32_t rack_clear_counter=0;
502 
503 static int
504 sysctl_rack_clear(SYSCTL_HANDLER_ARGS)
505 {
506 	uint32_t stat;
507 	int32_t error;
508 
509 	error = SYSCTL_OUT(req, &rack_clear_counter, sizeof(uint32_t));
510 	if (error || req->newptr == NULL)
511 		return error;
512 
513 	error = SYSCTL_IN(req, &stat, sizeof(uint32_t));
514 	if (error)
515 		return (error);
516 	if (stat == 1) {
517 #ifdef INVARIANTS
518 		printf("Clearing RACK counters\n");
519 #endif
520 		counter_u64_zero(rack_badfr);
521 		counter_u64_zero(rack_badfr_bytes);
522 		counter_u64_zero(rack_rtm_prr_retran);
523 		counter_u64_zero(rack_rtm_prr_newdata);
524 		counter_u64_zero(rack_timestamp_mismatch);
525 		counter_u64_zero(rack_reorder_seen);
526 		counter_u64_zero(rack_tlp_tot);
527 		counter_u64_zero(rack_tlp_newdata);
528 		counter_u64_zero(rack_tlp_retran);
529 		counter_u64_zero(rack_tlp_retran_bytes);
530 		counter_u64_zero(rack_tlp_retran_fail);
531 		counter_u64_zero(rack_to_tot);
532 		counter_u64_zero(rack_to_arm_rack);
533 		counter_u64_zero(rack_to_arm_tlp);
534 		counter_u64_zero(rack_paced_segments);
535 		counter_u64_zero(rack_calc_zero);
536 		counter_u64_zero(rack_calc_nonzero);
537 		counter_u64_zero(rack_unpaced_segments);
538 		counter_u64_zero(rack_saw_enobuf);
539 		counter_u64_zero(rack_saw_enetunreach);
540 		counter_u64_zero(rack_per_timer_hole);
541 		counter_u64_zero(rack_to_alloc_hard);
542 		counter_u64_zero(rack_to_alloc_emerg);
543 		counter_u64_zero(rack_sack_proc_all);
544 		counter_u64_zero(rack_sack_proc_short);
545 		counter_u64_zero(rack_sack_proc_restart);
546 		counter_u64_zero(rack_to_alloc);
547 		counter_u64_zero(rack_to_alloc_limited);
548 		counter_u64_zero(rack_alloc_limited_conns);
549 		counter_u64_zero(rack_split_limited);
550 		counter_u64_zero(rack_find_high);
551 		counter_u64_zero(rack_sack_attacks_detected);
552 		counter_u64_zero(rack_sack_attacks_reversed);
553 		counter_u64_zero(rack_sack_used_next_merge);
554 		counter_u64_zero(rack_sack_used_prev_merge);
555 		counter_u64_zero(rack_sack_splits);
556 		counter_u64_zero(rack_sack_skipped_acked);
557 		counter_u64_zero(rack_ack_total);
558 		counter_u64_zero(rack_express_sack);
559 		counter_u64_zero(rack_sack_total);
560 		counter_u64_zero(rack_move_none);
561 		counter_u64_zero(rack_move_some);
562 		counter_u64_zero(rack_used_tlpmethod);
563 		counter_u64_zero(rack_used_tlpmethod2);
564 		counter_u64_zero(rack_enter_tlp_calc);
565 		counter_u64_zero(rack_progress_drops);
566 		counter_u64_zero(rack_tlp_does_nada);
567 		counter_u64_zero(rack_try_scwnd);
568 		counter_u64_zero(rack_collapsed_win);
569 	}
570 	rack_clear_counter = 0;
571 	return (0);
572 }
573 
574 static void
575 rack_init_sysctls(void)
576 {
577 	struct sysctl_oid *rack_counters;
578 	struct sysctl_oid *rack_attack;
579 	struct sysctl_oid *rack_pacing;
580 	struct sysctl_oid *rack_timely;
581 	struct sysctl_oid *rack_timers;
582 	struct sysctl_oid *rack_tlp;
583 	struct sysctl_oid *rack_misc;
584 	struct sysctl_oid *rack_measure;
585 	struct sysctl_oid *rack_probertt;
586 
587 	rack_attack = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
588 	    SYSCTL_CHILDREN(rack_sysctl_root),
589 	    OID_AUTO,
590 	    "sack_attack",
591 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
592 	    "Rack Sack Attack Counters and Controls");
593 	rack_counters = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
594 	    SYSCTL_CHILDREN(rack_sysctl_root),
595 	    OID_AUTO,
596 	    "stats",
597 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
598 	    "Rack Counters");
599 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
600 	    SYSCTL_CHILDREN(rack_sysctl_root),
601 	    OID_AUTO, "rate_sample_method", CTLFLAG_RW,
602 	    &rack_rate_sample_method , USE_RTT_LOW,
603 	    "What method should we use for rate sampling 0=high, 1=low ");
604 	/* Probe rtt related controls */
605 	rack_probertt = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
606 	    SYSCTL_CHILDREN(rack_sysctl_root),
607 	    OID_AUTO,
608 	    "probertt",
609 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
610 	    "ProbeRTT related Controls");
611 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
612 	    SYSCTL_CHILDREN(rack_probertt),
613 	    OID_AUTO, "exit_per_hpb", CTLFLAG_RW,
614 	    &rack_atexit_prtt_hbp, 130,
615 	    "What percentage above goodput do we clamp CA/SS to at exit on high-BDP path 110%");
616 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
617 	    SYSCTL_CHILDREN(rack_probertt),
618 	    OID_AUTO, "exit_per_nonhpb", CTLFLAG_RW,
619 	    &rack_atexit_prtt, 130,
620 	    "What percentage above goodput do we clamp CA/SS to at exit on a non high-BDP path 100%");
621 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
622 	    SYSCTL_CHILDREN(rack_probertt),
623 	    OID_AUTO, "gp_per_mul", CTLFLAG_RW,
624 	    &rack_per_of_gp_probertt, 60,
625 	    "What percentage of goodput do we pace at in probertt");
626 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
627 	    SYSCTL_CHILDREN(rack_probertt),
628 	    OID_AUTO, "gp_per_reduce", CTLFLAG_RW,
629 	    &rack_per_of_gp_probertt_reduce, 10,
630 	    "What percentage of goodput do we reduce every gp_srtt");
631 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
632 	    SYSCTL_CHILDREN(rack_probertt),
633 	    OID_AUTO, "gp_per_low", CTLFLAG_RW,
634 	    &rack_per_of_gp_lowthresh, 40,
635 	    "What percentage of goodput do we allow the multiplier to fall to");
636 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
637 	    SYSCTL_CHILDREN(rack_probertt),
638 	    OID_AUTO, "time_between", CTLFLAG_RW,
639 	    & rack_time_between_probertt, 96000000,
640 	    "How many useconds between the lowest rtt falling must past before we enter probertt");
641 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
642 	    SYSCTL_CHILDREN(rack_probertt),
643 	    OID_AUTO, "safety", CTLFLAG_RW,
644 	    &rack_probe_rtt_safety_val, 2000000,
645 	    "If not zero, provides a maximum usecond that you can stay in probertt (2sec = 2000000)");
646 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
647 	    SYSCTL_CHILDREN(rack_probertt),
648 	    OID_AUTO, "sets_cwnd", CTLFLAG_RW,
649 	    &rack_probe_rtt_sets_cwnd, 0,
650 	    "Do we set the cwnd too (if always_lower is on)");
651 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
652 	    SYSCTL_CHILDREN(rack_probertt),
653 	    OID_AUTO, "maxdrainsrtts", CTLFLAG_RW,
654 	    &rack_max_drain_wait, 2,
655 	    "Maximum number of gp_srtt's to hold in drain waiting for flight to reach goal");
656 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
657 	    SYSCTL_CHILDREN(rack_probertt),
658 	    OID_AUTO, "mustdrainsrtts", CTLFLAG_RW,
659 	    &rack_must_drain, 1,
660 	    "We must drain this many gp_srtt's waiting for flight to reach goal");
661 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
662 	    SYSCTL_CHILDREN(rack_probertt),
663 	    OID_AUTO, "goal_use_min_entry", CTLFLAG_RW,
664 	    &rack_probertt_use_min_rtt_entry, 1,
665 	    "Should we use the min-rtt to calculate the goal rtt (else gp_srtt) at entry");
666 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
667 	    SYSCTL_CHILDREN(rack_probertt),
668 	    OID_AUTO, "goal_use_min_exit", CTLFLAG_RW,
669 	    &rack_probertt_use_min_rtt_exit, 0,
670 	    "How to set cwnd at exit, 0 - dynamic, 1 - use min-rtt, 2 - use curgprtt, 3 - entry gp-rtt");
671 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
672 	    SYSCTL_CHILDREN(rack_probertt),
673 	    OID_AUTO, "length_div", CTLFLAG_RW,
674 	    &rack_probertt_gpsrtt_cnt_div, 0,
675 	    "How many recent goodput srtt periods plus hold tim does probertt last (bottom of fraction)");
676 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
677 	    SYSCTL_CHILDREN(rack_probertt),
678 	    OID_AUTO, "length_mul", CTLFLAG_RW,
679 	    &rack_probertt_gpsrtt_cnt_mul, 0,
680 	    "How many recent goodput srtt periods plus hold tim does probertt last (top of fraction)");
681 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
682 	    SYSCTL_CHILDREN(rack_probertt),
683 	    OID_AUTO, "holdtim_at_target", CTLFLAG_RW,
684 	    &rack_min_probertt_hold, 200000,
685 	    "What is the minimum time we hold probertt at target");
686 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
687 	    SYSCTL_CHILDREN(rack_probertt),
688 	    OID_AUTO, "filter_life", CTLFLAG_RW,
689 	    &rack_probertt_filter_life, 10000000,
690 	    "What is the time for the filters life in useconds");
691 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
692 	    SYSCTL_CHILDREN(rack_probertt),
693 	    OID_AUTO, "lower_within", CTLFLAG_RW,
694 	    &rack_probertt_lower_within, 10,
695 	    "If the rtt goes lower within this percentage of the time, go into probe-rtt");
696 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
697 	    SYSCTL_CHILDREN(rack_probertt),
698 	    OID_AUTO, "must_move", CTLFLAG_RW,
699 	    &rack_min_rtt_movement, 250,
700 	    "How much is the minimum movement in rtt to count as a drop for probertt purposes");
701 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
702 	    SYSCTL_CHILDREN(rack_probertt),
703 	    OID_AUTO, "clear_is_cnts", CTLFLAG_RW,
704 	    &rack_probertt_clear_is, 1,
705 	    "Do we clear I/S counts on exiting probe-rtt");
706 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
707 	    SYSCTL_CHILDREN(rack_probertt),
708 	    OID_AUTO, "hbp_extra_drain", CTLFLAG_RW,
709 	    &rack_max_drain_hbp, 1,
710 	    "How many extra drain gpsrtt's do we get in highly buffered paths");
711 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
712 	    SYSCTL_CHILDREN(rack_probertt),
713 	    OID_AUTO, "hbp_threshold", CTLFLAG_RW,
714 	    &rack_hbp_thresh, 3,
715 	    "We are highly buffered if min_rtt_seen / max_rtt_seen > this-threshold");
716 	/* Pacing related sysctls */
717 	rack_pacing = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
718 	    SYSCTL_CHILDREN(rack_sysctl_root),
719 	    OID_AUTO,
720 	    "pacing",
721 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
722 	    "Pacing related Controls");
723 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
724 	    SYSCTL_CHILDREN(rack_pacing),
725 	    OID_AUTO, "max_pace_over", CTLFLAG_RW,
726 	    &rack_max_per_above, 30,
727 	    "What is the maximum allowable percentage that we can pace above (so 30 = 130% of our goal)");
728 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
729 	    SYSCTL_CHILDREN(rack_pacing),
730 	    OID_AUTO, "pace_to_one", CTLFLAG_RW,
731 	    &rack_pace_one_seg, 0,
732 	    "Do we allow low b/w pacing of 1MSS instead of two");
733 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
734 	    SYSCTL_CHILDREN(rack_pacing),
735 	    OID_AUTO, "limit_wsrtt", CTLFLAG_RW,
736 	    &rack_limit_time_with_srtt, 0,
737 	    "Do we limit pacing time based on srtt");
738 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
739 	    SYSCTL_CHILDREN(rack_pacing),
740 	    OID_AUTO, "init_win", CTLFLAG_RW,
741 	    &rack_default_init_window, 0,
742 	    "Do we have a rack initial window 0 = system default");
743 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
744 	    SYSCTL_CHILDREN(rack_pacing),
745 	    OID_AUTO, "hw_pacing_adjust", CTLFLAG_RW,
746 	    &rack_hw_pace_adjust, 0,
747 	    "What percentage do we raise the MSS by (11 = 1.1%)");
748 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
749 	    SYSCTL_CHILDREN(rack_pacing),
750 	    OID_AUTO, "gp_per_ss", CTLFLAG_RW,
751 	    &rack_per_of_gp_ss, 250,
752 	    "If non zero, what percentage of goodput to pace at in slow start");
753 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
754 	    SYSCTL_CHILDREN(rack_pacing),
755 	    OID_AUTO, "gp_per_ca", CTLFLAG_RW,
756 	    &rack_per_of_gp_ca, 150,
757 	    "If non zero, what percentage of goodput to pace at in congestion avoidance");
758 	SYSCTL_ADD_U16(&rack_sysctl_ctx,
759 	    SYSCTL_CHILDREN(rack_pacing),
760 	    OID_AUTO, "gp_per_rec", CTLFLAG_RW,
761 	    &rack_per_of_gp_rec, 200,
762 	    "If non zero, what percentage of goodput to pace at in recovery");
763 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
764 	    SYSCTL_CHILDREN(rack_pacing),
765 	    OID_AUTO, "pace_max_seg", CTLFLAG_RW,
766 	    &rack_hptsi_segments, 40,
767 	    "What size is the max for TSO segments in pacing and burst mitigation");
768 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
769 	    SYSCTL_CHILDREN(rack_pacing),
770 	    OID_AUTO, "burst_reduces", CTLFLAG_RW,
771 	    &rack_slot_reduction, 4,
772 	    "When doing only burst mitigation what is the reduce divisor");
773 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
774 	    SYSCTL_CHILDREN(rack_sysctl_root),
775 	    OID_AUTO, "use_pacing", CTLFLAG_RW,
776 	    &rack_pace_every_seg, 0,
777 	    "If set we use pacing, if clear we use only the original burst mitigation");
778 
779 	rack_timely = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
780 	    SYSCTL_CHILDREN(rack_sysctl_root),
781 	    OID_AUTO,
782 	    "timely",
783 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
784 	    "Rack Timely RTT Controls");
785 	/* Timely based GP dynmics */
786 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
787 	    SYSCTL_CHILDREN(rack_timely),
788 	    OID_AUTO, "upper", CTLFLAG_RW,
789 	    &rack_gp_per_bw_mul_up, 2,
790 	    "Rack timely upper range for equal b/w (in percentage)");
791 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
792 	    SYSCTL_CHILDREN(rack_timely),
793 	    OID_AUTO, "lower", CTLFLAG_RW,
794 	    &rack_gp_per_bw_mul_down, 4,
795 	    "Rack timely lower range for equal b/w (in percentage)");
796 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
797 	    SYSCTL_CHILDREN(rack_timely),
798 	    OID_AUTO, "rtt_max_mul", CTLFLAG_RW,
799 	    &rack_gp_rtt_maxmul, 3,
800 	    "Rack timely multipler of lowest rtt for rtt_max");
801 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
802 	    SYSCTL_CHILDREN(rack_timely),
803 	    OID_AUTO, "rtt_min_div", CTLFLAG_RW,
804 	    &rack_gp_rtt_mindiv, 4,
805 	    "Rack timely divisor used for rtt + (rtt * mul/divisor) for check for lower rtt");
806 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
807 	    SYSCTL_CHILDREN(rack_timely),
808 	    OID_AUTO, "rtt_min_mul", CTLFLAG_RW,
809 	    &rack_gp_rtt_minmul, 1,
810 	    "Rack timely multiplier used for rtt + (rtt * mul/divisor) for check for lower rtt");
811 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
812 	    SYSCTL_CHILDREN(rack_timely),
813 	    OID_AUTO, "decrease", CTLFLAG_RW,
814 	    &rack_gp_decrease_per, 20,
815 	    "Rack timely decrease percentage of our GP multiplication factor");
816 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
817 	    SYSCTL_CHILDREN(rack_timely),
818 	    OID_AUTO, "increase", CTLFLAG_RW,
819 	    &rack_gp_increase_per, 2,
820 	    "Rack timely increase perentage of our GP multiplication factor");
821 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
822 	    SYSCTL_CHILDREN(rack_timely),
823 	    OID_AUTO, "lowerbound", CTLFLAG_RW,
824 	    &rack_per_lower_bound, 50,
825 	    "Rack timely lowest percentage we allow GP multiplier to fall to");
826 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
827 	    SYSCTL_CHILDREN(rack_timely),
828 	    OID_AUTO, "upperboundss", CTLFLAG_RW,
829 	    &rack_per_upper_bound_ss, 0,
830 	    "Rack timely higest percentage we allow GP multiplier in SS to raise to (0 is no upperbound)");
831 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
832 	    SYSCTL_CHILDREN(rack_timely),
833 	    OID_AUTO, "upperboundca", CTLFLAG_RW,
834 	    &rack_per_upper_bound_ca, 0,
835 	    "Rack timely higest percentage we allow GP multiplier to CA raise to (0 is no upperbound)");
836 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
837 	    SYSCTL_CHILDREN(rack_timely),
838 	    OID_AUTO, "dynamicgp", CTLFLAG_RW,
839 	    &rack_do_dyn_mul, 0,
840 	    "Rack timely do we enable dynmaic timely goodput by default");
841 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
842 	    SYSCTL_CHILDREN(rack_timely),
843 	    OID_AUTO, "no_rec_red", CTLFLAG_RW,
844 	    &rack_gp_no_rec_chg, 1,
845 	    "Rack timely do we prohibit the recovery multiplier from being lowered");
846 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
847 	    SYSCTL_CHILDREN(rack_timely),
848 	    OID_AUTO, "red_clear_cnt", CTLFLAG_RW,
849 	    &rack_timely_dec_clear, 6,
850 	    "Rack timely what threshold do we count to before another boost during b/w decent");
851 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
852 	    SYSCTL_CHILDREN(rack_timely),
853 	    OID_AUTO, "max_push_rise", CTLFLAG_RW,
854 	    &rack_timely_max_push_rise, 3,
855 	    "Rack timely how many times do we push up with b/w increase");
856 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
857 	    SYSCTL_CHILDREN(rack_timely),
858 	    OID_AUTO, "max_push_drop", CTLFLAG_RW,
859 	    &rack_timely_max_push_drop, 3,
860 	    "Rack timely how many times do we push back on b/w decent");
861 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
862 	    SYSCTL_CHILDREN(rack_timely),
863 	    OID_AUTO, "min_segs", CTLFLAG_RW,
864 	    &rack_timely_min_segs, 4,
865 	    "Rack timely when setting the cwnd what is the min num segments");
866 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
867 	    SYSCTL_CHILDREN(rack_timely),
868 	    OID_AUTO, "noback_max", CTLFLAG_RW,
869 	    &rack_use_max_for_nobackoff, 0,
870 	    "Rack timely when deciding if to backoff on a loss, do we use under max rtt else min");
871 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
872 	    SYSCTL_CHILDREN(rack_timely),
873 	    OID_AUTO, "interim_timely_only", CTLFLAG_RW,
874 	    &rack_timely_int_timely_only, 0,
875 	    "Rack timely when doing interim timely's do we only do timely (no b/w consideration)");
876 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
877 	    SYSCTL_CHILDREN(rack_timely),
878 	    OID_AUTO, "nonstop", CTLFLAG_RW,
879 	    &rack_timely_no_stopping, 0,
880 	    "Rack timely don't stop increase");
881 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
882 	    SYSCTL_CHILDREN(rack_timely),
883 	    OID_AUTO, "dec_raise_thresh", CTLFLAG_RW,
884 	    &rack_down_raise_thresh, 100,
885 	    "If the CA or SS is below this threshold raise on the first 3 b/w lowers (0=always)");
886 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
887 	    SYSCTL_CHILDREN(rack_timely),
888 	    OID_AUTO, "bottom_drag_segs", CTLFLAG_RW,
889 	    &rack_req_segs, 1,
890 	    "Bottom dragging if not these many segments outstanding and room");
891 
892 	/* TLP and Rack related parameters */
893 	rack_tlp = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
894 	    SYSCTL_CHILDREN(rack_sysctl_root),
895 	    OID_AUTO,
896 	    "tlp",
897 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
898 	    "TLP and Rack related Controls");
899 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
900 	    SYSCTL_CHILDREN(rack_tlp),
901 	    OID_AUTO, "use_rrr", CTLFLAG_RW,
902 	    &use_rack_rr, 1,
903 	    "Do we use Rack Rapid Recovery");
904 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
905 	    SYSCTL_CHILDREN(rack_tlp),
906 	    OID_AUTO, "nonrxt_use_cr", CTLFLAG_RW,
907 	    &rack_non_rxt_use_cr, 0,
908 	    "Do we use ss/ca rate if in recovery we are transmitting a new data chunk");
909 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
910 	    SYSCTL_CHILDREN(rack_tlp),
911 	    OID_AUTO, "tlpmethod", CTLFLAG_RW,
912 	    &rack_tlp_threshold_use, TLP_USE_TWO_ONE,
913 	    "What method do we do for TLP time calc 0=no-de-ack-comp, 1=ID, 2=2.1, 3=2.2");
914 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
915 	    SYSCTL_CHILDREN(rack_tlp),
916 	    OID_AUTO, "limit", CTLFLAG_RW,
917 	    &rack_tlp_limit, 2,
918 	    "How many TLP's can be sent without sending new data");
919 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
920 	    SYSCTL_CHILDREN(rack_tlp),
921 	    OID_AUTO, "use_greater", CTLFLAG_RW,
922 	    &rack_tlp_use_greater, 1,
923 	    "Should we use the rack_rtt time if its greater than srtt");
924 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
925 	    SYSCTL_CHILDREN(rack_tlp),
926 	    OID_AUTO, "tlpminto", CTLFLAG_RW,
927 	    &rack_tlp_min, 10,
928 	    "TLP minimum timeout per the specification (10ms)");
929 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
930 	    SYSCTL_CHILDREN(rack_tlp),
931 	    OID_AUTO, "send_oldest", CTLFLAG_RW,
932 	    &rack_always_send_oldest, 0,
933 	    "Should we always send the oldest TLP and RACK-TLP");
934 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
935 	    SYSCTL_CHILDREN(rack_tlp),
936 	    OID_AUTO, "rack_tlimit", CTLFLAG_RW,
937 	    &rack_limited_retran, 0,
938 	    "How many times can a rack timeout drive out sends");
939 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
940 	    SYSCTL_CHILDREN(rack_tlp),
941 	    OID_AUTO, "tlp_retry", CTLFLAG_RW,
942 	    &rack_tlp_max_resend, 2,
943 	    "How many times does TLP retry a single segment or multiple with no ACK");
944 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
945 	    SYSCTL_CHILDREN(rack_tlp),
946 	    OID_AUTO, "tlp_cwnd_flag", CTLFLAG_RW,
947 	    &rack_lower_cwnd_at_tlp, 0,
948 	    "When a TLP completes a retran should we enter recovery");
949 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
950 	    SYSCTL_CHILDREN(rack_tlp),
951 	    OID_AUTO, "reorder_thresh", CTLFLAG_RW,
952 	    &rack_reorder_thresh, 2,
953 	    "What factor for rack will be added when seeing reordering (shift right)");
954 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
955 	    SYSCTL_CHILDREN(rack_tlp),
956 	    OID_AUTO, "rtt_tlp_thresh", CTLFLAG_RW,
957 	    &rack_tlp_thresh, 1,
958 	    "What divisor for TLP rtt/retran will be added (1=rtt, 2=1/2 rtt etc)");
959 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
960 	    SYSCTL_CHILDREN(rack_tlp),
961 	    OID_AUTO, "reorder_fade", CTLFLAG_RW,
962 	    &rack_reorder_fade, 0,
963 	    "Does reorder detection fade, if so how many ms (0 means never)");
964 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
965 	    SYSCTL_CHILDREN(rack_tlp),
966 	    OID_AUTO, "pktdelay", CTLFLAG_RW,
967 	    &rack_pkt_delay, 1,
968 	    "Extra RACK time (in ms) besides reordering thresh");
969 
970 	/* Timer related controls */
971 	rack_timers = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
972 	    SYSCTL_CHILDREN(rack_sysctl_root),
973 	    OID_AUTO,
974 	    "timers",
975 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
976 	    "Timer related controls");
977 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
978 	    SYSCTL_CHILDREN(rack_timers),
979 	    OID_AUTO, "persmin", CTLFLAG_RW,
980 	    &rack_persist_min, 250,
981 	    "What is the minimum time in milliseconds between persists");
982 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
983 	    SYSCTL_CHILDREN(rack_timers),
984 	    OID_AUTO, "persmax", CTLFLAG_RW,
985 	    &rack_persist_max, 2000,
986 	    "What is the largest delay in milliseconds between persists");
987 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
988 	    SYSCTL_CHILDREN(rack_timers),
989 	    OID_AUTO, "delayed_ack", CTLFLAG_RW,
990 	    &rack_delayed_ack_time, 200,
991 	    "Delayed ack time (200ms)");
992 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
993 	    SYSCTL_CHILDREN(rack_timers),
994 	    OID_AUTO, "minrto", CTLFLAG_RW,
995 	    &rack_rto_min, 0,
996 	    "Minimum RTO in ms -- set with caution below 1000 due to TLP");
997 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
998 	    SYSCTL_CHILDREN(rack_timers),
999 	    OID_AUTO, "maxrto", CTLFLAG_RW,
1000 	    &rack_rto_max, 0,
1001 	    "Maxiumum RTO in ms -- should be at least as large as min_rto");
1002 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1003 	    SYSCTL_CHILDREN(rack_timers),
1004 	    OID_AUTO, "minto", CTLFLAG_RW,
1005 	    &rack_min_to, 1,
1006 	    "Minimum rack timeout in milliseconds");
1007 	/* Measure controls */
1008 	rack_measure = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1009 	    SYSCTL_CHILDREN(rack_sysctl_root),
1010 	    OID_AUTO,
1011 	    "measure",
1012 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1013 	    "Measure related controls");
1014 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1015 	    SYSCTL_CHILDREN(rack_measure),
1016 	    OID_AUTO, "wma_divisor", CTLFLAG_RW,
1017 	    &rack_wma_divisor, 8,
1018 	    "When doing b/w calculation what is the  divisor for the WMA");
1019 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1020 	    SYSCTL_CHILDREN(rack_measure),
1021 	    OID_AUTO, "end_cwnd", CTLFLAG_RW,
1022 	    &rack_cwnd_block_ends_measure, 0,
1023 	    "Does a cwnd just-return end the measurement window (app limited)");
1024 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1025 	    SYSCTL_CHILDREN(rack_measure),
1026 	    OID_AUTO, "end_rwnd", CTLFLAG_RW,
1027 	    &rack_rwnd_block_ends_measure, 0,
1028 	    "Does an rwnd just-return end the measurement window (app limited -- not persists)");
1029 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1030 	    SYSCTL_CHILDREN(rack_measure),
1031 	    OID_AUTO, "min_target", CTLFLAG_RW,
1032 	    &rack_def_data_window, 20,
1033 	    "What is the minimum target window (in mss) for a GP measurements");
1034 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1035 	    SYSCTL_CHILDREN(rack_measure),
1036 	    OID_AUTO, "goal_bdp", CTLFLAG_RW,
1037 	    &rack_goal_bdp, 2,
1038 	    "What is the goal BDP to measure");
1039 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1040 	    SYSCTL_CHILDREN(rack_measure),
1041 	    OID_AUTO, "min_srtts", CTLFLAG_RW,
1042 	    &rack_min_srtts, 1,
1043 	    "What is the goal BDP to measure");
1044 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1045 	    SYSCTL_CHILDREN(rack_measure),
1046 	    OID_AUTO, "min_measure_tim", CTLFLAG_RW,
1047 	    &rack_min_measure_usec, 0,
1048 	    "What is the Minimum time time for a measurement if 0, this is off");
1049 	/* Misc rack controls */
1050 	rack_misc = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
1051 	    SYSCTL_CHILDREN(rack_sysctl_root),
1052 	    OID_AUTO,
1053 	    "misc",
1054 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1055 	    "Misc related controls");
1056 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1057 	    SYSCTL_CHILDREN(rack_misc),
1058 	    OID_AUTO, "shared_cwnd", CTLFLAG_RW,
1059 	    &rack_enable_shared_cwnd, 0,
1060 	    "Should RACK try to use the shared cwnd on connections where allowed");
1061 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1062 	    SYSCTL_CHILDREN(rack_misc),
1063 	    OID_AUTO, "limits_on_scwnd", CTLFLAG_RW,
1064 	    &rack_limits_scwnd, 1,
1065 	    "Should RACK place low end time limits on the shared cwnd feature");
1066 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1067 	    SYSCTL_CHILDREN(rack_misc),
1068 	    OID_AUTO, "non_paced_lro_queue", CTLFLAG_RW,
1069 	    &rack_enable_mqueue_for_nonpaced, 0,
1070 	    "Should RACK use mbuf queuing for non-paced connections");
1071 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1072 	    SYSCTL_CHILDREN(rack_misc),
1073 	    OID_AUTO, "iMac_dack", CTLFLAG_RW,
1074 	    &rack_use_imac_dack, 0,
1075 	    "Should RACK try to emulate iMac delayed ack");
1076 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1077 	    SYSCTL_CHILDREN(rack_misc),
1078 	    OID_AUTO, "no_prr", CTLFLAG_RW,
1079 	    &rack_disable_prr, 0,
1080 	    "Should RACK not use prr and only pace (must have pacing on)");
1081 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1082 	    SYSCTL_CHILDREN(rack_misc),
1083 	    OID_AUTO, "bb_verbose", CTLFLAG_RW,
1084 	    &rack_verbose_logging, 0,
1085 	    "Should RACK black box logging be verbose");
1086 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1087 	    SYSCTL_CHILDREN(rack_misc),
1088 	    OID_AUTO, "data_after_close", CTLFLAG_RW,
1089 	    &rack_ignore_data_after_close, 1,
1090 	    "Do we hold off sending a RST until all pending data is ack'd");
1091 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1092 	    SYSCTL_CHILDREN(rack_misc),
1093 	    OID_AUTO, "no_sack_needed", CTLFLAG_RW,
1094 	    &rack_sack_not_required, 0,
1095 	    "Do we allow rack to run on connections not supporting SACK");
1096 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1097 	    SYSCTL_CHILDREN(rack_misc),
1098 	    OID_AUTO, "recovery_loss_prop", CTLFLAG_RW,
1099 	    &rack_use_proportional_reduce, 0,
1100 	    "Should we proportionaly reduce cwnd based on the number of losses ");
1101 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1102 	    SYSCTL_CHILDREN(rack_misc),
1103 	    OID_AUTO, "recovery_prop", CTLFLAG_RW,
1104 	    &rack_proportional_rate, 10,
1105 	    "What percent reduction per loss");
1106 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1107 	    SYSCTL_CHILDREN(rack_misc),
1108 	    OID_AUTO, "prr_sendalot", CTLFLAG_RW,
1109 	    &rack_send_a_lot_in_prr, 1,
1110 	    "Send a lot in prr");
1111 	SYSCTL_ADD_S32(&rack_sysctl_ctx,
1112 	    SYSCTL_CHILDREN(rack_misc),
1113 	    OID_AUTO, "earlyrecovery", CTLFLAG_RW,
1114 	    &rack_early_recovery, 1,
1115 	    "Do we do early recovery with rack");
1116 	/* Sack Attacker detection stuff */
1117 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1118 	    SYSCTL_CHILDREN(rack_attack),
1119 	    OID_AUTO, "detect_highsackratio", CTLFLAG_RW,
1120 	    &rack_highest_sack_thresh_seen, 0,
1121 	    "Highest sack to ack ratio seen");
1122 	SYSCTL_ADD_U32(&rack_sysctl_ctx,
1123 	    SYSCTL_CHILDREN(rack_attack),
1124 	    OID_AUTO, "detect_highmoveratio", CTLFLAG_RW,
1125 	    &rack_highest_move_thresh_seen, 0,
1126 	    "Highest move to non-move ratio seen");
1127 	rack_ack_total = counter_u64_alloc(M_WAITOK);
1128 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1129 	    SYSCTL_CHILDREN(rack_attack),
1130 	    OID_AUTO, "acktotal", CTLFLAG_RD,
1131 	    &rack_ack_total,
1132 	    "Total number of Ack's");
1133 	rack_express_sack = counter_u64_alloc(M_WAITOK);
1134 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1135 	    SYSCTL_CHILDREN(rack_attack),
1136 	    OID_AUTO, "exp_sacktotal", CTLFLAG_RD,
1137 	    &rack_express_sack,
1138 	    "Total expresss number of Sack's");
1139 	rack_sack_total = counter_u64_alloc(M_WAITOK);
1140 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1141 	    SYSCTL_CHILDREN(rack_attack),
1142 	    OID_AUTO, "sacktotal", CTLFLAG_RD,
1143 	    &rack_sack_total,
1144 	    "Total number of SACKs");
1145 	rack_move_none = counter_u64_alloc(M_WAITOK);
1146 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1147 	    SYSCTL_CHILDREN(rack_attack),
1148 	    OID_AUTO, "move_none", CTLFLAG_RD,
1149 	    &rack_move_none,
1150 	    "Total number of SACK index reuse of postions under threshold");
1151 	rack_move_some = counter_u64_alloc(M_WAITOK);
1152 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1153 	    SYSCTL_CHILDREN(rack_attack),
1154 	    OID_AUTO, "move_some", CTLFLAG_RD,
1155 	    &rack_move_some,
1156 	    "Total number of SACK index reuse of postions over threshold");
1157 	rack_sack_attacks_detected = counter_u64_alloc(M_WAITOK);
1158 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1159 	    SYSCTL_CHILDREN(rack_attack),
1160 	    OID_AUTO, "attacks", CTLFLAG_RD,
1161 	    &rack_sack_attacks_detected,
1162 	    "Total number of SACK attackers that had sack disabled");
1163 	rack_sack_attacks_reversed = counter_u64_alloc(M_WAITOK);
1164 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1165 	    SYSCTL_CHILDREN(rack_attack),
1166 	    OID_AUTO, "reversed", CTLFLAG_RD,
1167 	    &rack_sack_attacks_reversed,
1168 	    "Total number of SACK attackers that were later determined false positive");
1169 	rack_sack_used_next_merge = counter_u64_alloc(M_WAITOK);
1170 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1171 	    SYSCTL_CHILDREN(rack_attack),
1172 	    OID_AUTO, "nextmerge", CTLFLAG_RD,
1173 	    &rack_sack_used_next_merge,
1174 	    "Total number of times we used the next merge");
1175 	rack_sack_used_prev_merge = counter_u64_alloc(M_WAITOK);
1176 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1177 	    SYSCTL_CHILDREN(rack_attack),
1178 	    OID_AUTO, "prevmerge", CTLFLAG_RD,
1179 	    &rack_sack_used_prev_merge,
1180 	    "Total number of times we used the prev merge");
1181 	/* Counters */
1182 	rack_badfr = counter_u64_alloc(M_WAITOK);
1183 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1184 	    SYSCTL_CHILDREN(rack_counters),
1185 	    OID_AUTO, "badfr", CTLFLAG_RD,
1186 	    &rack_badfr, "Total number of bad FRs");
1187 	rack_badfr_bytes = counter_u64_alloc(M_WAITOK);
1188 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1189 	    SYSCTL_CHILDREN(rack_counters),
1190 	    OID_AUTO, "badfr_bytes", CTLFLAG_RD,
1191 	    &rack_badfr_bytes, "Total number of bad FRs");
1192 	rack_rtm_prr_retran = counter_u64_alloc(M_WAITOK);
1193 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1194 	    SYSCTL_CHILDREN(rack_counters),
1195 	    OID_AUTO, "prrsndret", CTLFLAG_RD,
1196 	    &rack_rtm_prr_retran,
1197 	    "Total number of prr based retransmits");
1198 	rack_rtm_prr_newdata = counter_u64_alloc(M_WAITOK);
1199 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1200 	    SYSCTL_CHILDREN(rack_counters),
1201 	    OID_AUTO, "prrsndnew", CTLFLAG_RD,
1202 	    &rack_rtm_prr_newdata,
1203 	    "Total number of prr based new transmits");
1204 	rack_timestamp_mismatch = counter_u64_alloc(M_WAITOK);
1205 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1206 	    SYSCTL_CHILDREN(rack_counters),
1207 	    OID_AUTO, "tsnf", CTLFLAG_RD,
1208 	    &rack_timestamp_mismatch,
1209 	    "Total number of timestamps that we could not find the reported ts");
1210 	rack_find_high = counter_u64_alloc(M_WAITOK);
1211 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1212 	    SYSCTL_CHILDREN(rack_counters),
1213 	    OID_AUTO, "findhigh", CTLFLAG_RD,
1214 	    &rack_find_high,
1215 	    "Total number of FIN causing find-high");
1216 	rack_reorder_seen = counter_u64_alloc(M_WAITOK);
1217 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1218 	    SYSCTL_CHILDREN(rack_counters),
1219 	    OID_AUTO, "reordering", CTLFLAG_RD,
1220 	    &rack_reorder_seen,
1221 	    "Total number of times we added delay due to reordering");
1222 	rack_tlp_tot = counter_u64_alloc(M_WAITOK);
1223 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1224 	    SYSCTL_CHILDREN(rack_counters),
1225 	    OID_AUTO, "tlp_to_total", CTLFLAG_RD,
1226 	    &rack_tlp_tot,
1227 	    "Total number of tail loss probe expirations");
1228 	rack_tlp_newdata = counter_u64_alloc(M_WAITOK);
1229 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1230 	    SYSCTL_CHILDREN(rack_counters),
1231 	    OID_AUTO, "tlp_new", CTLFLAG_RD,
1232 	    &rack_tlp_newdata,
1233 	    "Total number of tail loss probe sending new data");
1234 	rack_tlp_retran = counter_u64_alloc(M_WAITOK);
1235 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1236 	    SYSCTL_CHILDREN(rack_counters),
1237 	    OID_AUTO, "tlp_retran", CTLFLAG_RD,
1238 	    &rack_tlp_retran,
1239 	    "Total number of tail loss probe sending retransmitted data");
1240 	rack_tlp_retran_bytes = counter_u64_alloc(M_WAITOK);
1241 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1242 	    SYSCTL_CHILDREN(rack_counters),
1243 	    OID_AUTO, "tlp_retran_bytes", CTLFLAG_RD,
1244 	    &rack_tlp_retran_bytes,
1245 	    "Total bytes of tail loss probe sending retransmitted data");
1246 	rack_tlp_retran_fail = counter_u64_alloc(M_WAITOK);
1247 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1248 	    SYSCTL_CHILDREN(rack_counters),
1249 	    OID_AUTO, "tlp_retran_fail", CTLFLAG_RD,
1250 	    &rack_tlp_retran_fail,
1251 	    "Total number of tail loss probe sending retransmitted data that failed (wait for t3)");
1252 	rack_to_tot = counter_u64_alloc(M_WAITOK);
1253 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1254 	    SYSCTL_CHILDREN(rack_counters),
1255 	    OID_AUTO, "rack_to_tot", CTLFLAG_RD,
1256 	    &rack_to_tot,
1257 	    "Total number of times the rack to expired");
1258 	rack_to_arm_rack = counter_u64_alloc(M_WAITOK);
1259 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1260 	    SYSCTL_CHILDREN(rack_counters),
1261 	    OID_AUTO, "arm_rack", CTLFLAG_RD,
1262 	    &rack_to_arm_rack,
1263 	    "Total number of times the rack timer armed");
1264 	rack_to_arm_tlp = counter_u64_alloc(M_WAITOK);
1265 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1266 	    SYSCTL_CHILDREN(rack_counters),
1267 	    OID_AUTO, "arm_tlp", CTLFLAG_RD,
1268 	    &rack_to_arm_tlp,
1269 	    "Total number of times the tlp timer armed");
1270 	rack_calc_zero = counter_u64_alloc(M_WAITOK);
1271 	rack_calc_nonzero = counter_u64_alloc(M_WAITOK);
1272 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1273 	    SYSCTL_CHILDREN(rack_counters),
1274 	    OID_AUTO, "calc_zero", CTLFLAG_RD,
1275 	    &rack_calc_zero,
1276 	    "Total number of times pacing time worked out to zero");
1277 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1278 	    SYSCTL_CHILDREN(rack_counters),
1279 	    OID_AUTO, "calc_nonzero", CTLFLAG_RD,
1280 	    &rack_calc_nonzero,
1281 	    "Total number of times pacing time worked out to non-zero");
1282 	rack_paced_segments = counter_u64_alloc(M_WAITOK);
1283 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1284 	    SYSCTL_CHILDREN(rack_counters),
1285 	    OID_AUTO, "paced", CTLFLAG_RD,
1286 	    &rack_paced_segments,
1287 	    "Total number of times a segment send caused hptsi");
1288 	rack_unpaced_segments = counter_u64_alloc(M_WAITOK);
1289 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1290 	    SYSCTL_CHILDREN(rack_counters),
1291 	    OID_AUTO, "unpaced", CTLFLAG_RD,
1292 	    &rack_unpaced_segments,
1293 	    "Total number of times a segment did not cause hptsi");
1294 	rack_saw_enobuf = counter_u64_alloc(M_WAITOK);
1295 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1296 	    SYSCTL_CHILDREN(rack_counters),
1297 	    OID_AUTO, "saw_enobufs", CTLFLAG_RD,
1298 	    &rack_saw_enobuf,
1299 	    "Total number of times a segment did not cause hptsi");
1300 	rack_saw_enetunreach = counter_u64_alloc(M_WAITOK);
1301 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1302 	    SYSCTL_CHILDREN(rack_counters),
1303 	    OID_AUTO, "saw_enetunreach", CTLFLAG_RD,
1304 	    &rack_saw_enetunreach,
1305 	    "Total number of times a segment did not cause hptsi");
1306 	rack_to_alloc = counter_u64_alloc(M_WAITOK);
1307 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1308 	    SYSCTL_CHILDREN(rack_counters),
1309 	    OID_AUTO, "allocs", CTLFLAG_RD,
1310 	    &rack_to_alloc,
1311 	    "Total allocations of tracking structures");
1312 	rack_to_alloc_hard = counter_u64_alloc(M_WAITOK);
1313 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1314 	    SYSCTL_CHILDREN(rack_counters),
1315 	    OID_AUTO, "allochard", CTLFLAG_RD,
1316 	    &rack_to_alloc_hard,
1317 	    "Total allocations done with sleeping the hard way");
1318 	rack_to_alloc_emerg = counter_u64_alloc(M_WAITOK);
1319 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1320 	    SYSCTL_CHILDREN(rack_counters),
1321 	    OID_AUTO, "allocemerg", CTLFLAG_RD,
1322 	    &rack_to_alloc_emerg,
1323 	    "Total allocations done from emergency cache");
1324 	rack_to_alloc_limited = counter_u64_alloc(M_WAITOK);
1325 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1326 	    SYSCTL_CHILDREN(rack_counters),
1327 	    OID_AUTO, "alloc_limited", CTLFLAG_RD,
1328 	    &rack_to_alloc_limited,
1329 	    "Total allocations dropped due to limit");
1330 	rack_alloc_limited_conns = counter_u64_alloc(M_WAITOK);
1331 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1332 	    SYSCTL_CHILDREN(rack_counters),
1333 	    OID_AUTO, "alloc_limited_conns", CTLFLAG_RD,
1334 	    &rack_alloc_limited_conns,
1335 	    "Connections with allocations dropped due to limit");
1336 	rack_split_limited = counter_u64_alloc(M_WAITOK);
1337 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1338 	    SYSCTL_CHILDREN(rack_counters),
1339 	    OID_AUTO, "split_limited", CTLFLAG_RD,
1340 	    &rack_split_limited,
1341 	    "Split allocations dropped due to limit");
1342 	rack_sack_proc_all = counter_u64_alloc(M_WAITOK);
1343 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1344 	    SYSCTL_CHILDREN(rack_counters),
1345 	    OID_AUTO, "sack_long", CTLFLAG_RD,
1346 	    &rack_sack_proc_all,
1347 	    "Total times we had to walk whole list for sack processing");
1348 	rack_sack_proc_restart = counter_u64_alloc(M_WAITOK);
1349 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1350 	    SYSCTL_CHILDREN(rack_counters),
1351 	    OID_AUTO, "sack_restart", CTLFLAG_RD,
1352 	    &rack_sack_proc_restart,
1353 	    "Total times we had to walk whole list due to a restart");
1354 	rack_sack_proc_short = counter_u64_alloc(M_WAITOK);
1355 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1356 	    SYSCTL_CHILDREN(rack_counters),
1357 	    OID_AUTO, "sack_short", CTLFLAG_RD,
1358 	    &rack_sack_proc_short,
1359 	    "Total times we took shortcut for sack processing");
1360 	rack_enter_tlp_calc = counter_u64_alloc(M_WAITOK);
1361 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1362 	    SYSCTL_CHILDREN(rack_counters),
1363 	    OID_AUTO, "tlp_calc_entered", CTLFLAG_RD,
1364 	    &rack_enter_tlp_calc,
1365 	    "Total times we called calc-tlp");
1366 	rack_used_tlpmethod = counter_u64_alloc(M_WAITOK);
1367 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1368 	    SYSCTL_CHILDREN(rack_counters),
1369 	    OID_AUTO, "hit_tlp_method", CTLFLAG_RD,
1370 	    &rack_used_tlpmethod,
1371 	    "Total number of runt sacks");
1372 	rack_used_tlpmethod2 = counter_u64_alloc(M_WAITOK);
1373 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1374 	    SYSCTL_CHILDREN(rack_counters),
1375 	    OID_AUTO, "hit_tlp_method2", CTLFLAG_RD,
1376 	    &rack_used_tlpmethod2,
1377 	    "Total number of times we hit TLP method 2");
1378 	rack_sack_skipped_acked = counter_u64_alloc(M_WAITOK);
1379 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1380 	    SYSCTL_CHILDREN(rack_attack),
1381 	    OID_AUTO, "skipacked", CTLFLAG_RD,
1382 	    &rack_sack_skipped_acked,
1383 	    "Total number of times we skipped previously sacked");
1384 	rack_sack_splits = counter_u64_alloc(M_WAITOK);
1385 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1386 	    SYSCTL_CHILDREN(rack_attack),
1387 	    OID_AUTO, "ofsplit", CTLFLAG_RD,
1388 	    &rack_sack_splits,
1389 	    "Total number of times we did the old fashion tree split");
1390 	rack_progress_drops = counter_u64_alloc(M_WAITOK);
1391 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1392 	    SYSCTL_CHILDREN(rack_counters),
1393 	    OID_AUTO, "prog_drops", CTLFLAG_RD,
1394 	    &rack_progress_drops,
1395 	    "Total number of progress drops");
1396 	rack_input_idle_reduces = counter_u64_alloc(M_WAITOK);
1397 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1398 	    SYSCTL_CHILDREN(rack_counters),
1399 	    OID_AUTO, "idle_reduce_oninput", CTLFLAG_RD,
1400 	    &rack_input_idle_reduces,
1401 	    "Total number of idle reductions on input");
1402 	rack_collapsed_win = counter_u64_alloc(M_WAITOK);
1403 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1404 	    SYSCTL_CHILDREN(rack_counters),
1405 	    OID_AUTO, "collapsed_win", CTLFLAG_RD,
1406 	    &rack_collapsed_win,
1407 	    "Total number of collapsed windows");
1408 	rack_tlp_does_nada = counter_u64_alloc(M_WAITOK);
1409 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1410 	    SYSCTL_CHILDREN(rack_counters),
1411 	    OID_AUTO, "tlp_nada", CTLFLAG_RD,
1412 	    &rack_tlp_does_nada,
1413 	    "Total number of nada tlp calls");
1414 	rack_try_scwnd = counter_u64_alloc(M_WAITOK);
1415 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1416 	    SYSCTL_CHILDREN(rack_counters),
1417 	    OID_AUTO, "tried_scwnd", CTLFLAG_RD,
1418 	    &rack_try_scwnd,
1419 	    "Total number of scwnd attempts");
1420 
1421 	rack_per_timer_hole = counter_u64_alloc(M_WAITOK);
1422 	SYSCTL_ADD_COUNTER_U64(&rack_sysctl_ctx,
1423 	    SYSCTL_CHILDREN(rack_counters),
1424 	    OID_AUTO, "timer_hole", CTLFLAG_RD,
1425 	    &rack_per_timer_hole,
1426 	    "Total persists start in timer hole");
1427 	COUNTER_ARRAY_ALLOC(rack_out_size, TCP_MSS_ACCT_SIZE, M_WAITOK);
1428 	SYSCTL_ADD_COUNTER_U64_ARRAY(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root),
1429 	    OID_AUTO, "outsize", CTLFLAG_RD,
1430 	    rack_out_size, TCP_MSS_ACCT_SIZE, "MSS send sizes");
1431 	COUNTER_ARRAY_ALLOC(rack_opts_arry, RACK_OPTS_SIZE, M_WAITOK);
1432 	SYSCTL_ADD_COUNTER_U64_ARRAY(&rack_sysctl_ctx, SYSCTL_CHILDREN(rack_sysctl_root),
1433 	    OID_AUTO, "opts", CTLFLAG_RD,
1434 	    rack_opts_arry, RACK_OPTS_SIZE, "RACK Option Stats");
1435 	SYSCTL_ADD_PROC(&rack_sysctl_ctx,
1436 	    SYSCTL_CHILDREN(rack_sysctl_root),
1437 	    OID_AUTO, "clear", CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE,
1438 	    &rack_clear_counter, 0, sysctl_rack_clear, "IU", "Clear counters");
1439 }
1440 
1441 static __inline int
1442 rb_map_cmp(struct rack_sendmap *b, struct rack_sendmap *a)
1443 {
1444 	if (SEQ_GEQ(b->r_start, a->r_start) &&
1445 	    SEQ_LT(b->r_start, a->r_end)) {
1446 		/*
1447 		 * The entry b is within the
1448 		 * block a. i.e.:
1449 		 * a --   |-------------|
1450 		 * b --   |----|
1451 		 * <or>
1452 		 * b --       |------|
1453 		 * <or>
1454 		 * b --       |-----------|
1455 		 */
1456 		return (0);
1457 	} else if (SEQ_GEQ(b->r_start, a->r_end)) {
1458 		/*
1459 		 * b falls as either the next
1460 		 * sequence block after a so a
1461 		 * is said to be smaller than b.
1462 		 * i.e:
1463 		 * a --   |------|
1464 		 * b --          |--------|
1465 		 * or
1466 		 * b --              |-----|
1467 		 */
1468 		return (1);
1469 	}
1470 	/*
1471 	 * Whats left is where a is
1472 	 * larger than b. i.e:
1473 	 * a --         |-------|
1474 	 * b --  |---|
1475 	 * or even possibly
1476 	 * b --   |--------------|
1477 	 */
1478 	return (-1);
1479 }
1480 
1481 RB_PROTOTYPE(rack_rb_tree_head, rack_sendmap, r_next, rb_map_cmp);
1482 RB_GENERATE(rack_rb_tree_head, rack_sendmap, r_next, rb_map_cmp);
1483 
1484 static uint32_t
1485 rc_init_window(struct tcp_rack *rack)
1486 {
1487 	uint32_t win;
1488 
1489 	if (rack->rc_init_win == 0) {
1490 		/*
1491 		 * Nothing set by the user, use the system stack
1492 		 * default.
1493 		 */
1494 		return(tcp_compute_initwnd(tcp_maxseg(rack->rc_tp)));
1495 	}
1496 	win = ctf_fixed_maxseg(rack->rc_tp) * rack->rc_init_win;
1497 	return(win);
1498 }
1499 
1500 static uint64_t
1501 rack_get_fixed_pacing_bw(struct tcp_rack *rack)
1502 {
1503 	if (IN_RECOVERY(rack->rc_tp->t_flags))
1504 		return (rack->r_ctl.rc_fixed_pacing_rate_rec);
1505 	else if (rack->r_ctl.cwnd_to_use < rack->rc_tp->snd_ssthresh)
1506 		return (rack->r_ctl.rc_fixed_pacing_rate_ss);
1507 	else
1508 		return (rack->r_ctl.rc_fixed_pacing_rate_ca);
1509 }
1510 
1511 static uint64_t
1512 rack_get_bw(struct tcp_rack *rack)
1513 {
1514 	if (rack->use_fixed_rate) {
1515 		/* Return the fixed pacing rate */
1516 		return (rack_get_fixed_pacing_bw(rack));
1517 	}
1518 	if (rack->r_ctl.gp_bw == 0) {
1519 		/*
1520 		 * We have yet no b/w measurement,
1521 		 * if we have a user set initial bw
1522 		 * return it. If we don't have that and
1523 		 * we have an srtt, use the tcp IW (10) to
1524 		 * calculate a fictional b/w over the SRTT
1525 		 * which is more or less a guess. Note
1526 		 * we don't use our IW from rack on purpose
1527 		 * so if we have like IW=30, we are not
1528 		 * calculating a "huge" b/w.
1529 		 */
1530 		uint64_t bw, srtt;
1531 		if (rack->r_ctl.init_rate)
1532 			return (rack->r_ctl.init_rate);
1533 
1534 		/* Has the user set a max peak rate? */
1535 #ifdef NETFLIX_PEAKRATE
1536 		if (rack->rc_tp->t_maxpeakrate)
1537 			return (rack->rc_tp->t_maxpeakrate);
1538 #endif
1539 		/* Ok lets come up with the IW guess, if we have a srtt */
1540 		if (rack->rc_tp->t_srtt == 0) {
1541 			/*
1542 			 * Go with old pacing method
1543 			 * i.e. burst mitigation only.
1544 			 */
1545 			return (0);
1546 		}
1547 		/* Ok lets get the initial TCP win (not racks) */
1548 		bw = tcp_compute_initwnd(tcp_maxseg(rack->rc_tp));
1549 		srtt = ((uint64_t)TICKS_2_USEC(rack->rc_tp->t_srtt) >> TCP_RTT_SHIFT);
1550 		bw *= (uint64_t)USECS_IN_SECOND;
1551 		bw /= srtt;
1552 		return (bw);
1553 	} else {
1554 		uint64_t bw;
1555 
1556 		if(rack->r_ctl.num_avg >= RACK_REQ_AVG) {
1557 			/* Averaging is done, we can return the value */
1558 			bw = rack->r_ctl.gp_bw;
1559 		} else {
1560 			/* Still doing initial average must calculate */
1561 			bw = rack->r_ctl.gp_bw / rack->r_ctl.num_avg;
1562 		}
1563 #ifdef NETFLIX_PEAKRATE
1564 		if ((rack->rc_tp->t_maxpeakrate) &&
1565 		    (bw > rack->rc_tp->t_maxpeakrate)) {
1566 			/* The user has set a peak rate to pace at
1567 			 * don't allow us to pace faster than that.
1568 			 */
1569 			return (rack->rc_tp->t_maxpeakrate);
1570 		}
1571 #endif
1572 		return (bw);
1573 	}
1574 }
1575 
1576 static uint16_t
1577 rack_get_output_gain(struct tcp_rack *rack, struct rack_sendmap *rsm)
1578 {
1579 	if (rack->use_fixed_rate) {
1580 		return (100);
1581 	} else if (rack->in_probe_rtt && (rsm == NULL))
1582 		return(rack->r_ctl.rack_per_of_gp_probertt);
1583 	else if ((IN_RECOVERY(rack->rc_tp->t_flags) &&
1584 		  rack->r_ctl.rack_per_of_gp_rec)) {
1585 		if (rsm) {
1586 			/* a retransmission always use the recovery rate */
1587 			return(rack->r_ctl.rack_per_of_gp_rec);
1588 		} else if (rack->rack_rec_nonrxt_use_cr) {
1589 			/* Directed to use the configured rate */
1590 			goto configured_rate;
1591 		} else if (rack->rack_no_prr &&
1592 			   (rack->r_ctl.rack_per_of_gp_rec > 100)) {
1593 			/* No PRR, lets just use the b/w estimate only */
1594 			return(100);
1595 		} else {
1596 			/*
1597 			 * Here we may have a non-retransmit but we
1598 			 * have no overrides, so just use the recovery
1599 			 * rate (prr is in effect).
1600 			 */
1601 			return(rack->r_ctl.rack_per_of_gp_rec);
1602 		}
1603 	}
1604 configured_rate:
1605 	/* For the configured rate we look at our cwnd vs the ssthresh */
1606 	if (rack->r_ctl.cwnd_to_use < rack->rc_tp->snd_ssthresh)
1607 		return (rack->r_ctl.rack_per_of_gp_ss);
1608 	else
1609 		return(rack->r_ctl.rack_per_of_gp_ca);
1610 }
1611 
1612 static uint64_t
1613 rack_get_output_bw(struct tcp_rack *rack, uint64_t bw, struct rack_sendmap *rsm)
1614 {
1615 	/*
1616 	 * We allow rack_per_of_gp_xx to dictate our bw rate we want.
1617 	 */
1618 	uint64_t bw_est;
1619 	uint64_t gain;
1620 
1621 	gain = (uint64_t)rack_get_output_gain(rack, rsm);
1622 	bw_est = bw * gain;
1623 	bw_est /= (uint64_t)100;
1624 	/* Never fall below the minimum (def 64kbps) */
1625 	if (bw_est < RACK_MIN_BW)
1626 		bw_est = RACK_MIN_BW;
1627 	return (bw_est);
1628 }
1629 
1630 static void
1631 rack_log_retran_reason(struct tcp_rack *rack, struct rack_sendmap *rsm, uint32_t tsused, uint32_t thresh, int mod)
1632 {
1633 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1634 		union tcp_log_stackspecific log;
1635 		struct timeval tv;
1636 
1637 		if ((mod != 1) && (rack_verbose_logging == 0)) {
1638 			/*
1639 			 * We get 3 values currently for mod
1640 			 * 1 - We are retransmitting and this tells the reason.
1641 			 * 2 - We are clearing a dup-ack count.
1642 			 * 3 - We are incrementing a dup-ack count.
1643 			 *
1644 			 * The clear/increment are only logged
1645 			 * if you have BBverbose on.
1646 			 */
1647 			return;
1648 		}
1649 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1650 		log.u_bbr.flex1 = tsused;
1651 		log.u_bbr.flex2 = thresh;
1652 		log.u_bbr.flex3 = rsm->r_flags;
1653 		log.u_bbr.flex4 = rsm->r_dupack;
1654 		log.u_bbr.flex5 = rsm->r_start;
1655 		log.u_bbr.flex6 = rsm->r_end;
1656 		log.u_bbr.flex8 = mod;
1657 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1658 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1659 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1660 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1661 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1662 		    &rack->rc_inp->inp_socket->so_rcv,
1663 		    &rack->rc_inp->inp_socket->so_snd,
1664 		    BBR_LOG_SETTINGS_CHG, 0,
1665 		    0, &log, false, &tv);
1666 	}
1667 }
1668 
1669 static void
1670 rack_log_to_start(struct tcp_rack *rack, uint32_t cts, uint32_t to, int32_t slot, uint8_t which)
1671 {
1672 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1673 		union tcp_log_stackspecific log;
1674 		struct timeval tv;
1675 
1676 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1677 		log.u_bbr.flex1 = TICKS_2_MSEC(rack->rc_tp->t_srtt >> TCP_RTT_SHIFT);
1678 		log.u_bbr.flex2 = to * 1000;
1679 		log.u_bbr.flex3 = rack->r_ctl.rc_hpts_flags;
1680 		log.u_bbr.flex4 = slot;
1681 		log.u_bbr.flex5 = rack->rc_inp->inp_hptsslot;
1682 		log.u_bbr.flex6 = rack->rc_tp->t_rxtcur;
1683 		log.u_bbr.flex7 = rack->rc_in_persist;
1684 		log.u_bbr.flex8 = which;
1685 		if (rack->rack_no_prr)
1686 			log.u_bbr.pkts_out = 0;
1687 		else
1688 			log.u_bbr.pkts_out = rack->r_ctl.rc_prr_sndcnt;
1689 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1690 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1691 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1692 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1693 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1694 		    &rack->rc_inp->inp_socket->so_rcv,
1695 		    &rack->rc_inp->inp_socket->so_snd,
1696 		    BBR_LOG_TIMERSTAR, 0,
1697 		    0, &log, false, &tv);
1698 	}
1699 }
1700 
1701 static void
1702 rack_log_to_event(struct tcp_rack *rack, int32_t to_num, struct rack_sendmap *rsm)
1703 {
1704 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1705 		union tcp_log_stackspecific log;
1706 		struct timeval tv;
1707 
1708 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1709 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1710 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1711 		log.u_bbr.flex8 = to_num;
1712 		log.u_bbr.flex1 = rack->r_ctl.rc_rack_min_rtt;
1713 		log.u_bbr.flex2 = rack->rc_rack_rtt;
1714 		if (rsm == NULL)
1715 			log.u_bbr.flex3 = 0;
1716 		else
1717 			log.u_bbr.flex3 = rsm->r_end - rsm->r_start;
1718 		if (rack->rack_no_prr)
1719 			log.u_bbr.flex5 = 0;
1720 		else
1721 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
1722 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1723 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1724 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1725 		    &rack->rc_inp->inp_socket->so_rcv,
1726 		    &rack->rc_inp->inp_socket->so_snd,
1727 		    BBR_LOG_RTO, 0,
1728 		    0, &log, false, &tv);
1729 	}
1730 }
1731 
1732 static void
1733 rack_log_rtt_upd(struct tcpcb *tp, struct tcp_rack *rack, uint32_t t, uint32_t len,
1734 		 struct rack_sendmap *rsm, int conf)
1735 {
1736 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
1737 		union tcp_log_stackspecific log;
1738 		struct timeval tv;
1739 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1740 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1741 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1742 		log.u_bbr.flex1 = t;
1743 		log.u_bbr.flex2 = len;
1744 		log.u_bbr.flex3 = rack->r_ctl.rc_rack_min_rtt * HPTS_USEC_IN_MSEC;
1745 		log.u_bbr.flex4 = rack->r_ctl.rack_rs.rs_rtt_lowest * HPTS_USEC_IN_MSEC;
1746 		log.u_bbr.flex5 = rack->r_ctl.rack_rs.rs_rtt_highest * HPTS_USEC_IN_MSEC;
1747 		log.u_bbr.flex6 = rack->r_ctl.rack_rs.rs_rtt_cnt;
1748 		log.u_bbr.flex7 = conf;
1749 		log.u_bbr.rttProp = (uint64_t)rack->r_ctl.rack_rs.rs_rtt_tot * (uint64_t)HPTS_USEC_IN_MSEC;
1750 		log.u_bbr.flex8 = rack->r_ctl.rc_rate_sample_method;
1751 		if (rack->rack_no_prr)
1752 			log.u_bbr.pkts_out = 0;
1753 		else
1754 			log.u_bbr.pkts_out = rack->r_ctl.rc_prr_sndcnt;
1755 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1756 		log.u_bbr.delivered = rack->r_ctl.rack_rs.rs_us_rtt;
1757 		log.u_bbr.pkts_out = rack->r_ctl.rack_rs.rs_flags;
1758 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1759 		if (rsm) {
1760 			log.u_bbr.pkt_epoch = rsm->r_start;
1761 			log.u_bbr.lost = rsm->r_end;
1762 			log.u_bbr.cwnd_gain = rsm->r_rtr_cnt;
1763 		} else {
1764 			/* Its a SYN */
1765 			log.u_bbr.pkt_epoch = rack->rc_tp->iss;
1766 			log.u_bbr.lost = 0;
1767 			log.u_bbr.cwnd_gain = 0;
1768 		}
1769 		/* Write out general bits of interest rrs here */
1770 		log.u_bbr.use_lt_bw = rack->rc_highly_buffered;
1771 		log.u_bbr.use_lt_bw <<= 1;
1772 		log.u_bbr.use_lt_bw |= rack->forced_ack;
1773 		log.u_bbr.use_lt_bw <<= 1;
1774 		log.u_bbr.use_lt_bw |= rack->rc_gp_dyn_mul;
1775 		log.u_bbr.use_lt_bw <<= 1;
1776 		log.u_bbr.use_lt_bw |= rack->in_probe_rtt;
1777 		log.u_bbr.use_lt_bw <<= 1;
1778 		log.u_bbr.use_lt_bw |= rack->measure_saw_probe_rtt;
1779 		log.u_bbr.use_lt_bw <<= 1;
1780 		log.u_bbr.use_lt_bw |= rack->app_limited_needs_set;
1781 		log.u_bbr.use_lt_bw <<= 1;
1782 		log.u_bbr.use_lt_bw |= rack->rc_gp_filled;
1783 		log.u_bbr.use_lt_bw <<= 1;
1784 		log.u_bbr.use_lt_bw |= rack->rc_dragged_bottom;
1785 		log.u_bbr.applimited = rack->r_ctl.rc_target_probertt_flight;
1786 		log.u_bbr.epoch = rack->r_ctl.rc_time_probertt_starts;
1787 		log.u_bbr.lt_epoch = rack->r_ctl.rc_time_probertt_entered;
1788 		log.u_bbr.cur_del_rate = rack->r_ctl.rc_lower_rtt_us_cts;
1789 		log.u_bbr.delRate = rack->r_ctl.rc_gp_srtt;
1790 		TCP_LOG_EVENTP(tp, NULL,
1791 		    &rack->rc_inp->inp_socket->so_rcv,
1792 		    &rack->rc_inp->inp_socket->so_snd,
1793 		    BBR_LOG_BBRRTT, 0,
1794 		    0, &log, false, &tv);
1795 	}
1796 }
1797 
1798 static void
1799 rack_log_rtt_sample(struct tcp_rack *rack, uint32_t rtt)
1800 {
1801 	/*
1802 	 * Log the rtt sample we are
1803 	 * applying to the srtt algorithm in
1804 	 * useconds.
1805 	 */
1806 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1807 		union tcp_log_stackspecific log;
1808 		struct timeval tv;
1809 
1810 		/* Convert our ms to a microsecond */
1811 		memset(&log, 0, sizeof(log));
1812 		log.u_bbr.flex1 = rtt * 1000;
1813 		log.u_bbr.flex2 = rack->r_ctl.ack_count;
1814 		log.u_bbr.flex3 = rack->r_ctl.sack_count;
1815 		log.u_bbr.flex4 = rack->r_ctl.sack_noextra_move;
1816 		log.u_bbr.flex5 = rack->r_ctl.sack_moved_extra;
1817 		log.u_bbr.flex8 = rack->sack_attack_disable;
1818 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1819 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1820 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1821 		    &rack->rc_inp->inp_socket->so_rcv,
1822 		    &rack->rc_inp->inp_socket->so_snd,
1823 		    TCP_LOG_RTT, 0,
1824 		    0, &log, false, &tv);
1825 	}
1826 }
1827 
1828 static inline void
1829 rack_log_progress_event(struct tcp_rack *rack, struct tcpcb *tp, uint32_t tick,  int event, int line)
1830 {
1831 	if (rack_verbose_logging && (tp->t_logstate != TCP_LOG_STATE_OFF)) {
1832 		union tcp_log_stackspecific log;
1833 		struct timeval tv;
1834 
1835 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1836 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1837 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1838 		log.u_bbr.flex1 = line;
1839 		log.u_bbr.flex2 = tick;
1840 		log.u_bbr.flex3 = tp->t_maxunacktime;
1841 		log.u_bbr.flex4 = tp->t_acktime;
1842 		log.u_bbr.flex8 = event;
1843 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1844 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1845 		TCP_LOG_EVENTP(tp, NULL,
1846 		    &rack->rc_inp->inp_socket->so_rcv,
1847 		    &rack->rc_inp->inp_socket->so_snd,
1848 		    BBR_LOG_PROGRESS, 0,
1849 		    0, &log, false, &tv);
1850 	}
1851 }
1852 
1853 static void
1854 rack_log_type_bbrsnd(struct tcp_rack *rack, uint32_t len, uint32_t slot, uint32_t cts, struct timeval *tv)
1855 {
1856 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1857 		union tcp_log_stackspecific log;
1858 
1859 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1860 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1861 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1862 		log.u_bbr.flex1 = slot;
1863 		if (rack->rack_no_prr)
1864 			log.u_bbr.flex2 = 0;
1865 		else
1866 			log.u_bbr.flex2 = rack->r_ctl.rc_prr_sndcnt;
1867 		log.u_bbr.flex7 = (0x0000ffff & rack->r_ctl.rc_hpts_flags);
1868 		log.u_bbr.flex8 = rack->rc_in_persist;
1869 		log.u_bbr.timeStamp = cts;
1870 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1871 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1872 		    &rack->rc_inp->inp_socket->so_rcv,
1873 		    &rack->rc_inp->inp_socket->so_snd,
1874 		    BBR_LOG_BBRSND, 0,
1875 		    0, &log, false, tv);
1876 	}
1877 }
1878 
1879 static void
1880 rack_log_doseg_done(struct tcp_rack *rack, uint32_t cts, int32_t nxt_pkt, int32_t did_out, int way_out)
1881 {
1882 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1883 		union tcp_log_stackspecific log;
1884 		struct timeval tv;
1885 
1886 		memset(&log, 0, sizeof(log));
1887 		log.u_bbr.flex1 = did_out;
1888 		log.u_bbr.flex2 = nxt_pkt;
1889 		log.u_bbr.flex3 = way_out;
1890 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
1891 		if (rack->rack_no_prr)
1892 			log.u_bbr.flex5 = 0;
1893 		else
1894 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
1895 		log.u_bbr.applimited = rack->r_ctl.rc_pace_min_segs;
1896 		log.u_bbr.flex7 = rack->r_wanted_output;
1897 		log.u_bbr.flex8 = rack->rc_in_persist;
1898 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1899 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1900 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1901 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1902 		    &rack->rc_inp->inp_socket->so_rcv,
1903 		    &rack->rc_inp->inp_socket->so_snd,
1904 		    BBR_LOG_DOSEG_DONE, 0,
1905 		    0, &log, false, &tv);
1906 	}
1907 }
1908 
1909 static void
1910 rack_log_type_hrdwtso(struct tcpcb *tp, struct tcp_rack *rack, int len, int mod, int32_t orig_len, int frm)
1911 {
1912 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
1913 		union tcp_log_stackspecific log;
1914 		struct timeval tv;
1915 		uint32_t cts;
1916 
1917 		memset(&log, 0, sizeof(log));
1918 		cts = tcp_get_usecs(&tv);
1919 		log.u_bbr.flex1 = rack->r_ctl.rc_pace_min_segs;
1920 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_max_segs;
1921 		log.u_bbr.flex4 = len;
1922 		log.u_bbr.flex5 = orig_len;
1923 		log.u_bbr.flex6 = rack->r_ctl.rc_sacked;
1924 		log.u_bbr.flex7 = mod;
1925 		log.u_bbr.flex8 = frm;
1926 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1927 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1928 		TCP_LOG_EVENTP(tp, NULL,
1929 		    &tp->t_inpcb->inp_socket->so_rcv,
1930 		    &tp->t_inpcb->inp_socket->so_snd,
1931 		    TCP_HDWR_PACE_SIZE, 0,
1932 		    0, &log, false, &tv);
1933 	}
1934 }
1935 
1936 static void
1937 rack_log_type_just_return(struct tcp_rack *rack, uint32_t cts, uint32_t tlen, uint32_t slot,
1938 			  uint8_t hpts_calling, int reason, uint32_t cwnd_to_use)
1939 {
1940 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1941 		union tcp_log_stackspecific log;
1942 		struct timeval tv;
1943 
1944 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1945 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1946 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1947 		log.u_bbr.flex1 = slot;
1948 		log.u_bbr.flex2 = rack->r_ctl.rc_hpts_flags;
1949 		log.u_bbr.flex4 = reason;
1950 		if (rack->rack_no_prr)
1951 			log.u_bbr.flex5 = 0;
1952 		else
1953 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
1954 		log.u_bbr.flex7 = hpts_calling;
1955 		log.u_bbr.flex8 = rack->rc_in_persist;
1956 		log.u_bbr.lt_epoch = cwnd_to_use;
1957 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
1958 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1959 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1960 		    &rack->rc_inp->inp_socket->so_rcv,
1961 		    &rack->rc_inp->inp_socket->so_snd,
1962 		    BBR_LOG_JUSTRET, 0,
1963 		    tlen, &log, false, &tv);
1964 	}
1965 }
1966 
1967 static void
1968 rack_log_to_cancel(struct tcp_rack *rack, int32_t hpts_removed, int line, uint32_t us_cts,
1969 		   struct timeval *tv, uint32_t flags_on_entry)
1970 {
1971 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1972 		union tcp_log_stackspecific log;
1973 
1974 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
1975 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
1976 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
1977 		log.u_bbr.flex1 = line;
1978 		log.u_bbr.flex2 = rack->r_ctl.rc_last_output_to;
1979 		log.u_bbr.flex3 = flags_on_entry;
1980 		log.u_bbr.flex4 = us_cts;
1981 		if (rack->rack_no_prr)
1982 			log.u_bbr.flex5 = 0;
1983 		else
1984 			log.u_bbr.flex5 = rack->r_ctl.rc_prr_sndcnt;
1985 		log.u_bbr.flex6 = rack->rc_tp->t_rxtcur;
1986 		log.u_bbr.flex7 = hpts_removed;
1987 		log.u_bbr.flex8 = 1;
1988 		log.u_bbr.applimited = rack->r_ctl.rc_hpts_flags;
1989 		log.u_bbr.timeStamp = us_cts;
1990 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
1991 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
1992 		    &rack->rc_inp->inp_socket->so_rcv,
1993 		    &rack->rc_inp->inp_socket->so_snd,
1994 		    BBR_LOG_TIMERCANC, 0,
1995 		    0, &log, false, tv);
1996 	}
1997 }
1998 
1999 static void
2000 rack_log_alt_to_to_cancel(struct tcp_rack *rack,
2001 			  uint32_t flex1, uint32_t flex2,
2002 			  uint32_t flex3, uint32_t flex4,
2003 			  uint32_t flex5, uint32_t flex6,
2004 			  uint16_t flex7, uint8_t mod)
2005 {
2006 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2007 		union tcp_log_stackspecific log;
2008 		struct timeval tv;
2009 
2010 		if (mod == 1) {
2011 			/* No you can't use 1, its for the real to cancel */
2012 			return;
2013 		}
2014 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2015 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2016 		log.u_bbr.flex1 = flex1;
2017 		log.u_bbr.flex2 = flex2;
2018 		log.u_bbr.flex3 = flex3;
2019 		log.u_bbr.flex4 = flex4;
2020 		log.u_bbr.flex5 = flex5;
2021 		log.u_bbr.flex6 = flex6;
2022 		log.u_bbr.flex7 = flex7;
2023 		log.u_bbr.flex8 =  mod;
2024 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2025 		    &rack->rc_inp->inp_socket->so_rcv,
2026 		    &rack->rc_inp->inp_socket->so_snd,
2027 		    BBR_LOG_TIMERCANC, 0,
2028 		    0, &log, false, &tv);
2029 	}
2030 }
2031 
2032 static void
2033 rack_log_to_processing(struct tcp_rack *rack, uint32_t cts, int32_t ret, int32_t timers)
2034 {
2035 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2036 		union tcp_log_stackspecific log;
2037 		struct timeval tv;
2038 
2039 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2040 		log.u_bbr.flex1 = timers;
2041 		log.u_bbr.flex2 = ret;
2042 		log.u_bbr.flex3 = rack->r_ctl.rc_timer_exp;
2043 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
2044 		log.u_bbr.flex5 = cts;
2045 		if (rack->rack_no_prr)
2046 			log.u_bbr.flex6 = 0;
2047 		else
2048 			log.u_bbr.flex6 = rack->r_ctl.rc_prr_sndcnt;
2049 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2050 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2051 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2052 		    &rack->rc_inp->inp_socket->so_rcv,
2053 		    &rack->rc_inp->inp_socket->so_snd,
2054 		    BBR_LOG_TO_PROCESS, 0,
2055 		    0, &log, false, &tv);
2056 	}
2057 }
2058 
2059 static void
2060 rack_log_to_prr(struct tcp_rack *rack, int frm, int orig_cwnd)
2061 {
2062 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2063 		union tcp_log_stackspecific log;
2064 		struct timeval tv;
2065 
2066 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2067 		log.u_bbr.flex1 = rack->r_ctl.rc_prr_out;
2068 		log.u_bbr.flex2 = rack->r_ctl.rc_prr_recovery_fs;
2069 		if (rack->rack_no_prr)
2070 			log.u_bbr.flex3 = 0;
2071 		else
2072 			log.u_bbr.flex3 = rack->r_ctl.rc_prr_sndcnt;
2073 		log.u_bbr.flex4 = rack->r_ctl.rc_prr_delivered;
2074 		log.u_bbr.flex5 = rack->r_ctl.rc_sacked;
2075 		log.u_bbr.flex6 = rack->r_ctl.rc_holes_rxt;
2076 		log.u_bbr.flex8 = frm;
2077 		log.u_bbr.pkts_out = orig_cwnd;
2078 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2079 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2080 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2081 		    &rack->rc_inp->inp_socket->so_rcv,
2082 		    &rack->rc_inp->inp_socket->so_snd,
2083 		    BBR_LOG_BBRUPD, 0,
2084 		    0, &log, false, &tv);
2085 	}
2086 }
2087 
2088 #ifdef NETFLIX_EXP_DETECTION
2089 static void
2090 rack_log_sad(struct tcp_rack *rack, int event)
2091 {
2092 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2093 		union tcp_log_stackspecific log;
2094 		struct timeval tv;
2095 
2096 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2097 		log.u_bbr.flex1 = rack->r_ctl.sack_count;
2098 		log.u_bbr.flex2 = rack->r_ctl.ack_count;
2099 		log.u_bbr.flex3 = rack->r_ctl.sack_moved_extra;
2100 		log.u_bbr.flex4 = rack->r_ctl.sack_noextra_move;
2101 		log.u_bbr.flex5 = rack->r_ctl.rc_num_maps_alloced;
2102 		log.u_bbr.flex6 = tcp_sack_to_ack_thresh;
2103 		log.u_bbr.pkts_out = tcp_sack_to_move_thresh;
2104 		log.u_bbr.lt_epoch = (tcp_force_detection << 8);
2105 		log.u_bbr.lt_epoch |= rack->do_detection;
2106 		log.u_bbr.applimited = tcp_map_minimum;
2107 		log.u_bbr.flex7 = rack->sack_attack_disable;
2108 		log.u_bbr.flex8 = event;
2109 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2110 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2111 		log.u_bbr.delivered = tcp_sad_decay_val;
2112 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2113 		    &rack->rc_inp->inp_socket->so_rcv,
2114 		    &rack->rc_inp->inp_socket->so_snd,
2115 		    TCP_SAD_DETECTION, 0,
2116 		    0, &log, false, &tv);
2117 	}
2118 }
2119 #endif
2120 
2121 static void
2122 rack_counter_destroy(void)
2123 {
2124 	counter_u64_free(rack_ack_total);
2125 	counter_u64_free(rack_express_sack);
2126 	counter_u64_free(rack_sack_total);
2127 	counter_u64_free(rack_move_none);
2128 	counter_u64_free(rack_move_some);
2129 	counter_u64_free(rack_sack_attacks_detected);
2130 	counter_u64_free(rack_sack_attacks_reversed);
2131 	counter_u64_free(rack_sack_used_next_merge);
2132 	counter_u64_free(rack_sack_used_prev_merge);
2133 	counter_u64_free(rack_badfr);
2134 	counter_u64_free(rack_badfr_bytes);
2135 	counter_u64_free(rack_rtm_prr_retran);
2136 	counter_u64_free(rack_rtm_prr_newdata);
2137 	counter_u64_free(rack_timestamp_mismatch);
2138 	counter_u64_free(rack_find_high);
2139 	counter_u64_free(rack_reorder_seen);
2140 	counter_u64_free(rack_tlp_tot);
2141 	counter_u64_free(rack_tlp_newdata);
2142 	counter_u64_free(rack_tlp_retran);
2143 	counter_u64_free(rack_tlp_retran_bytes);
2144 	counter_u64_free(rack_tlp_retran_fail);
2145 	counter_u64_free(rack_to_tot);
2146 	counter_u64_free(rack_to_arm_rack);
2147 	counter_u64_free(rack_to_arm_tlp);
2148 	counter_u64_free(rack_calc_zero);
2149 	counter_u64_free(rack_calc_nonzero);
2150 	counter_u64_free(rack_paced_segments);
2151 	counter_u64_free(rack_unpaced_segments);
2152 	counter_u64_free(rack_saw_enobuf);
2153 	counter_u64_free(rack_saw_enetunreach);
2154 	counter_u64_free(rack_to_alloc);
2155 	counter_u64_free(rack_to_alloc_hard);
2156 	counter_u64_free(rack_to_alloc_emerg);
2157 	counter_u64_free(rack_to_alloc_limited);
2158 	counter_u64_free(rack_alloc_limited_conns);
2159 	counter_u64_free(rack_split_limited);
2160 	counter_u64_free(rack_sack_proc_all);
2161 	counter_u64_free(rack_sack_proc_restart);
2162 	counter_u64_free(rack_sack_proc_short);
2163 	counter_u64_free(rack_enter_tlp_calc);
2164 	counter_u64_free(rack_used_tlpmethod);
2165 	counter_u64_free(rack_used_tlpmethod2);
2166 	counter_u64_free(rack_sack_skipped_acked);
2167 	counter_u64_free(rack_sack_splits);
2168 	counter_u64_free(rack_progress_drops);
2169 	counter_u64_free(rack_input_idle_reduces);
2170 	counter_u64_free(rack_collapsed_win);
2171 	counter_u64_free(rack_tlp_does_nada);
2172 	counter_u64_free(rack_try_scwnd);
2173 	counter_u64_free(rack_per_timer_hole);
2174 	COUNTER_ARRAY_FREE(rack_out_size, TCP_MSS_ACCT_SIZE);
2175 	COUNTER_ARRAY_FREE(rack_opts_arry, RACK_OPTS_SIZE);
2176 }
2177 
2178 static struct rack_sendmap *
2179 rack_alloc(struct tcp_rack *rack)
2180 {
2181 	struct rack_sendmap *rsm;
2182 
2183 	rsm = uma_zalloc(rack_zone, M_NOWAIT);
2184 	if (rsm) {
2185 		rack->r_ctl.rc_num_maps_alloced++;
2186 		counter_u64_add(rack_to_alloc, 1);
2187 		return (rsm);
2188 	}
2189 	if (rack->rc_free_cnt) {
2190 		counter_u64_add(rack_to_alloc_emerg, 1);
2191 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
2192 		TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_tnext);
2193 		rack->rc_free_cnt--;
2194 		return (rsm);
2195 	}
2196 	return (NULL);
2197 }
2198 
2199 static struct rack_sendmap *
2200 rack_alloc_full_limit(struct tcp_rack *rack)
2201 {
2202 	if ((V_tcp_map_entries_limit > 0) &&
2203 	    (rack->do_detection == 0) &&
2204 	    (rack->r_ctl.rc_num_maps_alloced >= V_tcp_map_entries_limit)) {
2205 		counter_u64_add(rack_to_alloc_limited, 1);
2206 		if (!rack->alloc_limit_reported) {
2207 			rack->alloc_limit_reported = 1;
2208 			counter_u64_add(rack_alloc_limited_conns, 1);
2209 		}
2210 		return (NULL);
2211 	}
2212 	return (rack_alloc(rack));
2213 }
2214 
2215 /* wrapper to allocate a sendmap entry, subject to a specific limit */
2216 static struct rack_sendmap *
2217 rack_alloc_limit(struct tcp_rack *rack, uint8_t limit_type)
2218 {
2219 	struct rack_sendmap *rsm;
2220 
2221 	if (limit_type) {
2222 		/* currently there is only one limit type */
2223 		if (V_tcp_map_split_limit > 0 &&
2224 		    (rack->do_detection == 0) &&
2225 		    rack->r_ctl.rc_num_split_allocs >= V_tcp_map_split_limit) {
2226 			counter_u64_add(rack_split_limited, 1);
2227 			if (!rack->alloc_limit_reported) {
2228 				rack->alloc_limit_reported = 1;
2229 				counter_u64_add(rack_alloc_limited_conns, 1);
2230 			}
2231 			return (NULL);
2232 		}
2233 	}
2234 
2235 	/* allocate and mark in the limit type, if set */
2236 	rsm = rack_alloc(rack);
2237 	if (rsm != NULL && limit_type) {
2238 		rsm->r_limit_type = limit_type;
2239 		rack->r_ctl.rc_num_split_allocs++;
2240 	}
2241 	return (rsm);
2242 }
2243 
2244 static void
2245 rack_free(struct tcp_rack *rack, struct rack_sendmap *rsm)
2246 {
2247 	if (rsm->r_flags & RACK_APP_LIMITED) {
2248 		if (rack->r_ctl.rc_app_limited_cnt > 0) {
2249 			rack->r_ctl.rc_app_limited_cnt--;
2250 		}
2251 	}
2252 	if (rsm->r_limit_type) {
2253 		/* currently there is only one limit type */
2254 		rack->r_ctl.rc_num_split_allocs--;
2255 	}
2256 	if (rsm == rack->r_ctl.rc_first_appl) {
2257 		if (rack->r_ctl.rc_app_limited_cnt == 0)
2258 			rack->r_ctl.rc_first_appl = NULL;
2259 		else {
2260 			/* Follow the next one out */
2261 			struct rack_sendmap fe;
2262 
2263 			fe.r_start = rsm->r_nseq_appl;
2264 			rack->r_ctl.rc_first_appl = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
2265 		}
2266 	}
2267 	if (rsm == rack->r_ctl.rc_resend)
2268 		rack->r_ctl.rc_resend = NULL;
2269 	if (rsm == rack->r_ctl.rc_rsm_at_retran)
2270 		rack->r_ctl.rc_rsm_at_retran = NULL;
2271 	if (rsm == rack->r_ctl.rc_end_appl)
2272 		rack->r_ctl.rc_end_appl = NULL;
2273 	if (rack->r_ctl.rc_tlpsend == rsm)
2274 		rack->r_ctl.rc_tlpsend = NULL;
2275 	if (rack->r_ctl.rc_sacklast == rsm)
2276 		rack->r_ctl.rc_sacklast = NULL;
2277 	if (rack->rc_free_cnt < rack_free_cache) {
2278 		memset(rsm, 0, sizeof(struct rack_sendmap));
2279 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_free, rsm, r_tnext);
2280 		rsm->r_limit_type = 0;
2281 		rack->rc_free_cnt++;
2282 		return;
2283 	}
2284 	rack->r_ctl.rc_num_maps_alloced--;
2285 	uma_zfree(rack_zone, rsm);
2286 }
2287 
2288 static uint32_t
2289 rack_get_measure_window(struct tcpcb *tp, struct tcp_rack *rack)
2290 {
2291 	uint64_t srtt, bw, len, tim;
2292 	uint32_t segsiz, def_len, minl;
2293 
2294 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
2295 	def_len = rack_def_data_window * segsiz;
2296 	if (rack->rc_gp_filled == 0) {
2297 		/*
2298 		 * We have no measurement (IW is in flight?) so
2299 		 * we can only guess using our data_window sysctl
2300 		 * value (usually 100MSS).
2301 		 */
2302 		return (def_len);
2303 	}
2304 	/*
2305 	 * Now we have a number of factors to consider.
2306 	 *
2307 	 * 1) We have a desired BDP which is usually
2308 	 *    at least 2.
2309 	 * 2) We have a minimum number of rtt's usually 1 SRTT
2310 	 *    but we allow it too to be more.
2311 	 * 3) We want to make sure a measurement last N useconds (if
2312 	 *    we have set rack_min_measure_usec.
2313 	 *
2314 	 * We handle the first concern here by trying to create a data
2315 	 * window of max(rack_def_data_window, DesiredBDP). The
2316 	 * second concern we handle in not letting the measurement
2317 	 * window end normally until at least the required SRTT's
2318 	 * have gone by which is done further below in
2319 	 * rack_enough_for_measurement(). Finally the third concern
2320 	 * we also handle here by calculating how long that time
2321 	 * would take at the current BW and then return the
2322 	 * max of our first calculation and that length. Note
2323 	 * that if rack_min_measure_usec is 0, we don't deal
2324 	 * with concern 3. Also for both Concern 1 and 3 an
2325 	 * application limited period could end the measurement
2326 	 * earlier.
2327 	 *
2328 	 * So lets calculate the BDP with the "known" b/w using
2329 	 * the SRTT has our rtt and then multiply it by the
2330 	 * goal.
2331 	 */
2332 	bw = rack_get_bw(rack);
2333 	srtt = ((uint64_t)TICKS_2_USEC(tp->t_srtt) >> TCP_RTT_SHIFT);
2334 	len = bw * srtt;
2335 	len /= (uint64_t)HPTS_USEC_IN_SEC;
2336 	len *= max(1, rack_goal_bdp);
2337         /* Now we need to round up to the nearest MSS */
2338 	len = roundup(len, segsiz);
2339 	if (rack_min_measure_usec) {
2340 		/* Now calculate our min length for this b/w */
2341 		tim = rack_min_measure_usec;
2342 		minl = (tim * bw) / (uint64_t)HPTS_USEC_IN_SEC;
2343 		if (minl == 0)
2344 			minl = 1;
2345 		minl = roundup(minl, segsiz);
2346 		if (len < minl)
2347 			len = minl;
2348 	}
2349 	/*
2350 	 * Now if we have a very small window we want
2351 	 * to attempt to get the window that is
2352 	 * as small as possible. This happens on
2353 	 * low b/w connections and we don't want to
2354 	 * span huge numbers of rtt's between measurements.
2355 	 *
2356 	 * We basically include 2 over our "MIN window" so
2357 	 * that the measurement can be shortened (possibly) by
2358 	 * an ack'ed packet.
2359 	 */
2360 	if (len < def_len)
2361 		return (max((uint32_t)len, ((MIN_GP_WIN+2) * segsiz)));
2362 	else
2363 		return (max((uint32_t)len, def_len));
2364 
2365 }
2366 
2367 static int
2368 rack_enough_for_measurement(struct tcpcb *tp, struct tcp_rack *rack, tcp_seq th_ack)
2369 {
2370 	uint32_t tim, srtts, segsiz;
2371 
2372 	/*
2373 	 * Has enough time passed for the GP measurement to be valid?
2374 	 */
2375 	if ((tp->snd_max == tp->snd_una) ||
2376 	    (th_ack == tp->snd_max)){
2377 		/* All is acked */
2378 		return (1);
2379 	}
2380 	if (SEQ_LT(th_ack, tp->gput_seq)) {
2381 		/* Not enough bytes yet */
2382 		return (0);
2383 	}
2384 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
2385 	if (SEQ_LT(th_ack, tp->gput_ack) &&
2386 	    ((th_ack - tp->gput_seq) < max(rc_init_window(rack), (MIN_GP_WIN * segsiz)))) {
2387 		/* Not enough bytes yet */
2388 		return (0);
2389 	}
2390 	if (rack->r_ctl.rc_first_appl &&
2391 	    (rack->r_ctl.rc_first_appl->r_start == th_ack)) {
2392 		/*
2393 		 * We are up to the app limited point
2394 		 * we have to measure irrespective of the time..
2395 		 */
2396 		return (1);
2397 	}
2398 	/* Now what about time? */
2399 	srtts = (rack->r_ctl.rc_gp_srtt * rack_min_srtts);
2400 	tim = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time) - tp->gput_ts;
2401 	if (tim >= srtts) {
2402 		return (1);
2403 	}
2404 	/* Nope not even a full SRTT has passed */
2405 	return (0);
2406 }
2407 
2408 static void
2409 rack_log_timely(struct tcp_rack *rack,
2410 		uint32_t logged, uint64_t cur_bw, uint64_t low_bnd,
2411 		uint64_t up_bnd, int line, uint8_t method)
2412 {
2413 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2414 		union tcp_log_stackspecific log;
2415 		struct timeval tv;
2416 
2417 		memset(&log, 0, sizeof(log));
2418 		log.u_bbr.flex1 = logged;
2419 		log.u_bbr.flex2 = rack->rc_gp_timely_inc_cnt;
2420 		log.u_bbr.flex2 <<= 4;
2421 		log.u_bbr.flex2 |= rack->rc_gp_timely_dec_cnt;
2422 		log.u_bbr.flex2 <<= 4;
2423 		log.u_bbr.flex2 |= rack->rc_gp_incr;
2424 		log.u_bbr.flex2 <<= 4;
2425 		log.u_bbr.flex2 |= rack->rc_gp_bwred;
2426 		log.u_bbr.flex3 = rack->rc_gp_incr;
2427 		log.u_bbr.flex4 = rack->r_ctl.rack_per_of_gp_ss;
2428 		log.u_bbr.flex5 = rack->r_ctl.rack_per_of_gp_ca;
2429 		log.u_bbr.flex6 = rack->r_ctl.rack_per_of_gp_rec;
2430 		log.u_bbr.flex7 = rack->rc_gp_bwred;
2431 		log.u_bbr.flex8 = method;
2432 		log.u_bbr.cur_del_rate = cur_bw;
2433 		log.u_bbr.delRate = low_bnd;
2434 		log.u_bbr.bw_inuse = up_bnd;
2435 		log.u_bbr.rttProp = rack_get_bw(rack);
2436 		log.u_bbr.pkt_epoch = line;
2437 		log.u_bbr.pkts_out = rack->r_ctl.rc_rtt_diff;
2438 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2439 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2440 		log.u_bbr.epoch = rack->r_ctl.rc_gp_srtt;
2441 		log.u_bbr.lt_epoch = rack->r_ctl.rc_prev_gp_srtt;
2442 		log.u_bbr.cwnd_gain = rack->rc_dragged_bottom;
2443 		log.u_bbr.cwnd_gain <<= 1;
2444 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_rec;
2445 		log.u_bbr.cwnd_gain <<= 1;
2446 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ss;
2447 		log.u_bbr.cwnd_gain <<= 1;
2448 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ca;
2449 		log.u_bbr.lost = rack->r_ctl.rc_loss_count;
2450 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2451 		    &rack->rc_inp->inp_socket->so_rcv,
2452 		    &rack->rc_inp->inp_socket->so_snd,
2453 		    TCP_TIMELY_WORK, 0,
2454 		    0, &log, false, &tv);
2455 	}
2456 }
2457 
2458 static int
2459 rack_bw_can_be_raised(struct tcp_rack *rack, uint64_t cur_bw, uint64_t last_bw_est, uint16_t mult)
2460 {
2461 	/*
2462 	 * Before we increase we need to know if
2463 	 * the estimate just made was less than
2464 	 * our pacing goal (i.e. (cur_bw * mult) > last_bw_est)
2465 	 *
2466 	 * If we already are pacing at a fast enough
2467 	 * rate to push us faster there is no sense of
2468 	 * increasing.
2469 	 *
2470 	 * We first caculate our actual pacing rate (ss or ca multipler
2471 	 * times our cur_bw).
2472 	 *
2473 	 * Then we take the last measured rate and multipy by our
2474 	 * maximum pacing overage to give us a max allowable rate.
2475 	 *
2476 	 * If our act_rate is smaller than our max_allowable rate
2477 	 * then we should increase. Else we should hold steady.
2478 	 *
2479 	 */
2480 	uint64_t act_rate, max_allow_rate;
2481 
2482 	if (rack_timely_no_stopping)
2483 		return (1);
2484 
2485 	if ((cur_bw == 0) || (last_bw_est == 0)) {
2486 		/*
2487 		 * Initial startup case or
2488 		 * everything is acked case.
2489 		 */
2490 		rack_log_timely(rack,  mult, cur_bw, 0, 0,
2491 				__LINE__, 9);
2492 		return (1);
2493 	}
2494 	if (mult <= 100) {
2495 		/*
2496 		 * We can always pace at or slightly above our rate.
2497 		 */
2498 		rack_log_timely(rack,  mult, cur_bw, 0, 0,
2499 				__LINE__, 9);
2500 		return (1);
2501 	}
2502 	act_rate = cur_bw * (uint64_t)mult;
2503 	act_rate /= 100;
2504 	max_allow_rate = last_bw_est * ((uint64_t)rack_max_per_above + (uint64_t)100);
2505 	max_allow_rate /= 100;
2506 	if (act_rate < max_allow_rate) {
2507 		/*
2508 		 * Here the rate we are actually pacing at
2509 		 * is smaller than 10% above our last measurement.
2510 		 * This means we are pacing below what we would
2511 		 * like to try to achieve (plus some wiggle room).
2512 		 */
2513 		rack_log_timely(rack,  mult, cur_bw, act_rate, max_allow_rate,
2514 				__LINE__, 9);
2515 		return (1);
2516 	} else {
2517 		/*
2518 		 * Here we are already pacing at least rack_max_per_above(10%)
2519 		 * what we are getting back. This indicates most likely
2520 		 * that we are being limited (cwnd/rwnd/app) and can't
2521 		 * get any more b/w. There is no sense of trying to
2522 		 * raise up the pacing rate its not speeding us up
2523 		 * and we already are pacing faster than we are getting.
2524 		 */
2525 		rack_log_timely(rack,  mult, cur_bw, act_rate, max_allow_rate,
2526 				__LINE__, 8);
2527 		return (0);
2528 	}
2529 }
2530 
2531 static void
2532 rack_validate_multipliers_at_or_above100(struct tcp_rack *rack)
2533 {
2534 	/*
2535 	 * When we drag bottom, we want to assure
2536 	 * that no multiplier is below 1.0, if so
2537 	 * we want to restore it to at least that.
2538 	 */
2539 	if (rack->r_ctl.rack_per_of_gp_rec  < 100) {
2540 		/* This is unlikely we usually do not touch recovery */
2541 		rack->r_ctl.rack_per_of_gp_rec = 100;
2542 	}
2543 	if (rack->r_ctl.rack_per_of_gp_ca < 100) {
2544 		rack->r_ctl.rack_per_of_gp_ca = 100;
2545 	}
2546 	if (rack->r_ctl.rack_per_of_gp_ss < 100) {
2547 		rack->r_ctl.rack_per_of_gp_ss = 100;
2548 	}
2549 }
2550 
2551 static void
2552 rack_validate_multipliers_at_or_below_100(struct tcp_rack *rack)
2553 {
2554 	if (rack->r_ctl.rack_per_of_gp_ca > 100) {
2555 		rack->r_ctl.rack_per_of_gp_ca = 100;
2556 	}
2557 	if (rack->r_ctl.rack_per_of_gp_ss > 100) {
2558 		rack->r_ctl.rack_per_of_gp_ss = 100;
2559 	}
2560 }
2561 
2562 static void
2563 rack_increase_bw_mul(struct tcp_rack *rack, int timely_says, uint64_t cur_bw, uint64_t last_bw_est, int override)
2564 {
2565 	int32_t  calc, logged, plus;
2566 
2567 	logged = 0;
2568 
2569 	if (override) {
2570 		/*
2571 		 * override is passed when we are
2572 		 * loosing b/w and making one last
2573 		 * gasp at trying to not loose out
2574 		 * to a new-reno flow.
2575 		 */
2576 		goto extra_boost;
2577 	}
2578 	/* In classic timely we boost by 5x if we have 5 increases in a row, lets not */
2579 	if (rack->rc_gp_incr &&
2580 	    ((rack->rc_gp_timely_inc_cnt + 1) >= RACK_TIMELY_CNT_BOOST)) {
2581 		/*
2582 		 * Reset and get 5 strokes more before the boost. Note
2583 		 * that the count is 0 based so we have to add one.
2584 		 */
2585 extra_boost:
2586 		plus = (uint32_t)rack_gp_increase_per * RACK_TIMELY_CNT_BOOST;
2587 		rack->rc_gp_timely_inc_cnt = 0;
2588 	} else
2589 		plus = (uint32_t)rack_gp_increase_per;
2590 	/* Must be at least 1% increase for true timely increases */
2591 	if ((plus < 1) &&
2592 	    ((rack->r_ctl.rc_rtt_diff <= 0) || (timely_says <= 0)))
2593 		plus = 1;
2594 	if (rack->rc_gp_saw_rec &&
2595 	    (rack->rc_gp_no_rec_chg == 0) &&
2596 	    rack_bw_can_be_raised(rack, cur_bw, last_bw_est,
2597 				  rack->r_ctl.rack_per_of_gp_rec)) {
2598 		/* We have been in recovery ding it too */
2599 		calc = rack->r_ctl.rack_per_of_gp_rec + plus;
2600 		if (calc > 0xffff)
2601 			calc = 0xffff;
2602 		logged |= 1;
2603 		rack->r_ctl.rack_per_of_gp_rec = (uint16_t)calc;
2604 		if (rack_per_upper_bound_ss &&
2605 		    (rack->rc_dragged_bottom == 0) &&
2606 		    (rack->r_ctl.rack_per_of_gp_rec > rack_per_upper_bound_ss))
2607 			rack->r_ctl.rack_per_of_gp_rec = rack_per_upper_bound_ss;
2608 	}
2609 	if (rack->rc_gp_saw_ca &&
2610 	    (rack->rc_gp_saw_ss == 0) &&
2611 	    rack_bw_can_be_raised(rack, cur_bw, last_bw_est,
2612 				  rack->r_ctl.rack_per_of_gp_ca)) {
2613 		/* In CA */
2614 		calc = rack->r_ctl.rack_per_of_gp_ca + plus;
2615 		if (calc > 0xffff)
2616 			calc = 0xffff;
2617 		logged |= 2;
2618 		rack->r_ctl.rack_per_of_gp_ca = (uint16_t)calc;
2619 		if (rack_per_upper_bound_ca &&
2620 		    (rack->rc_dragged_bottom == 0) &&
2621 		    (rack->r_ctl.rack_per_of_gp_ca > rack_per_upper_bound_ca))
2622 			rack->r_ctl.rack_per_of_gp_ca = rack_per_upper_bound_ca;
2623 	}
2624 	if (rack->rc_gp_saw_ss &&
2625 	    rack_bw_can_be_raised(rack, cur_bw, last_bw_est,
2626 				  rack->r_ctl.rack_per_of_gp_ss)) {
2627 		/* In SS */
2628 		calc = rack->r_ctl.rack_per_of_gp_ss + plus;
2629 		if (calc > 0xffff)
2630 			calc = 0xffff;
2631 		rack->r_ctl.rack_per_of_gp_ss = (uint16_t)calc;
2632 		if (rack_per_upper_bound_ss &&
2633 		    (rack->rc_dragged_bottom == 0) &&
2634 		    (rack->r_ctl.rack_per_of_gp_ss > rack_per_upper_bound_ss))
2635 			rack->r_ctl.rack_per_of_gp_ss = rack_per_upper_bound_ss;
2636 		logged |= 4;
2637 	}
2638 	if (logged &&
2639 	    (rack->rc_gp_incr == 0)){
2640 		/* Go into increment mode */
2641 		rack->rc_gp_incr = 1;
2642 		rack->rc_gp_timely_inc_cnt = 0;
2643 	}
2644 	if (rack->rc_gp_incr &&
2645 	    logged &&
2646 	    (rack->rc_gp_timely_inc_cnt < RACK_TIMELY_CNT_BOOST)) {
2647 		rack->rc_gp_timely_inc_cnt++;
2648 	}
2649 	rack_log_timely(rack,  logged, plus, 0, 0,
2650 			__LINE__, 1);
2651 }
2652 
2653 static uint32_t
2654 rack_get_decrease(struct tcp_rack *rack, uint32_t curper, int32_t rtt_diff)
2655 {
2656 	/*
2657 	 * norm_grad = rtt_diff / minrtt;
2658 	 * new_per = curper  * (1 - B * norm_grad)
2659 	 *
2660 	 * B = rack_gp_decrease_per (default 10%)
2661 	 * rtt_dif = input var current rtt-diff
2662 	 * curper = input var current percentage
2663 	 * minrtt = from rack filter
2664 	 *
2665 	 */
2666 	uint64_t perf;
2667 
2668 	perf = (((uint64_t)curper * ((uint64_t)1000000 -
2669 		    ((uint64_t)rack_gp_decrease_per * (uint64_t)10000 *
2670 		     (((uint64_t)rtt_diff * (uint64_t)1000000)/
2671 		      (uint64_t)get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt)))/
2672 		     (uint64_t)1000000)) /
2673 		(uint64_t)1000000);
2674 	if (perf > curper) {
2675 		/* TSNH */
2676 		perf = curper - 1;
2677 	}
2678 	return ((uint32_t)perf);
2679 }
2680 
2681 static uint32_t
2682 rack_decrease_highrtt(struct tcp_rack *rack, uint32_t curper, uint32_t rtt)
2683 {
2684 	/*
2685 	 *                                   highrttthresh
2686 	 * result = curper * (1 - (B * ( 1 -  ------          ))
2687 	 *                                     gp_srtt
2688 	 *
2689 	 * B = rack_gp_decrease_per (default 10%)
2690 	 * highrttthresh = filter_min * rack_gp_rtt_maxmul
2691 	 */
2692 	uint64_t perf;
2693 	uint32_t highrttthresh;
2694 
2695 	highrttthresh = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_maxmul;
2696 
2697 	perf =  (((uint64_t)curper * ((uint64_t)1000000 -
2698 				    ((uint64_t)rack_gp_decrease_per * ((uint64_t)1000000 -
2699 					((uint64_t)highrttthresh * (uint64_t)1000000) /
2700 						    (uint64_t)rtt)) / 100)) /(uint64_t)1000000);
2701 	return (perf);
2702 }
2703 
2704 static void
2705 rack_decrease_bw_mul(struct tcp_rack *rack, int timely_says, uint32_t rtt, int32_t rtt_diff)
2706 {
2707 	uint64_t logvar, logvar2, logvar3;
2708 	uint32_t logged, new_per, ss_red, ca_red, rec_red, alt, val;
2709 
2710 	if (rack->rc_gp_incr) {
2711 		/* Turn off increment counting  */
2712 		rack->rc_gp_incr = 0;
2713 		rack->rc_gp_timely_inc_cnt = 0;
2714 	}
2715 	ss_red = ca_red = rec_red = 0;
2716 	logged = 0;
2717 	/* Calculate the reduction value */
2718 	if (rtt_diff < 0) {
2719 		rtt_diff *= -1;
2720 	}
2721 	/* Must be at least 1% reduction */
2722 	if (rack->rc_gp_saw_rec && (rack->rc_gp_no_rec_chg == 0)) {
2723 		/* We have been in recovery ding it too */
2724 		if (timely_says == 2) {
2725 			new_per = rack_decrease_highrtt(rack, rack->r_ctl.rack_per_of_gp_rec, rtt);
2726 			alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
2727 			if (alt < new_per)
2728 				val = alt;
2729 			else
2730 				val = new_per;
2731 		} else
2732 			 val = new_per = alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
2733 		if (rack->r_ctl.rack_per_of_gp_rec > val) {
2734 			rec_red = (rack->r_ctl.rack_per_of_gp_rec - val);
2735 			rack->r_ctl.rack_per_of_gp_rec = (uint16_t)val;
2736 		} else {
2737 			rack->r_ctl.rack_per_of_gp_rec = rack_per_lower_bound;
2738 			rec_red = 0;
2739 		}
2740 		if (rack_per_lower_bound > rack->r_ctl.rack_per_of_gp_rec)
2741 			rack->r_ctl.rack_per_of_gp_rec = rack_per_lower_bound;
2742 		logged |= 1;
2743 	}
2744 	if (rack->rc_gp_saw_ss) {
2745 		/* Sent in SS */
2746 		if (timely_says == 2) {
2747 			new_per = rack_decrease_highrtt(rack, rack->r_ctl.rack_per_of_gp_ss, rtt);
2748 			alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
2749 			if (alt < new_per)
2750 				val = alt;
2751 			else
2752 				val = new_per;
2753 		} else
2754 			val = new_per = alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_ss, rtt_diff);
2755 		if (rack->r_ctl.rack_per_of_gp_ss > new_per) {
2756 			ss_red = rack->r_ctl.rack_per_of_gp_ss - val;
2757 			rack->r_ctl.rack_per_of_gp_ss = (uint16_t)val;
2758 		} else {
2759 			ss_red = new_per;
2760 			rack->r_ctl.rack_per_of_gp_ss = rack_per_lower_bound;
2761 			logvar = new_per;
2762 			logvar <<= 32;
2763 			logvar |= alt;
2764 			logvar2 = (uint32_t)rtt;
2765 			logvar2 <<= 32;
2766 			logvar2 |= (uint32_t)rtt_diff;
2767 			logvar3 = rack_gp_rtt_maxmul;
2768 			logvar3 <<= 32;
2769 			logvar3 |= get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
2770 			rack_log_timely(rack, timely_says,
2771 					logvar2, logvar3,
2772 					logvar, __LINE__, 10);
2773 		}
2774 		if (rack_per_lower_bound > rack->r_ctl.rack_per_of_gp_ss)
2775 			rack->r_ctl.rack_per_of_gp_ss = rack_per_lower_bound;
2776 		logged |= 4;
2777 	} else 	if (rack->rc_gp_saw_ca) {
2778 		/* Sent in CA */
2779 		if (timely_says == 2) {
2780 			new_per = rack_decrease_highrtt(rack, rack->r_ctl.rack_per_of_gp_ca, rtt);
2781 			alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_rec, rtt_diff);
2782 			if (alt < new_per)
2783 				val = alt;
2784 			else
2785 				val = new_per;
2786 		} else
2787 			val = new_per = alt = rack_get_decrease(rack, rack->r_ctl.rack_per_of_gp_ca, rtt_diff);
2788 		if (rack->r_ctl.rack_per_of_gp_ca > val) {
2789 			ca_red = rack->r_ctl.rack_per_of_gp_ca - val;
2790 			rack->r_ctl.rack_per_of_gp_ca = (uint16_t)val;
2791 		} else {
2792 			rack->r_ctl.rack_per_of_gp_ca = rack_per_lower_bound;
2793 			ca_red = 0;
2794 			logvar = new_per;
2795 			logvar <<= 32;
2796 			logvar |= alt;
2797 			logvar2 = (uint32_t)rtt;
2798 			logvar2 <<= 32;
2799 			logvar2 |= (uint32_t)rtt_diff;
2800 			logvar3 = rack_gp_rtt_maxmul;
2801 			logvar3 <<= 32;
2802 			logvar3 |= get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
2803 			rack_log_timely(rack, timely_says,
2804 					logvar2, logvar3,
2805 					logvar, __LINE__, 10);
2806 		}
2807 		if (rack_per_lower_bound > rack->r_ctl.rack_per_of_gp_ca)
2808 			rack->r_ctl.rack_per_of_gp_ca = rack_per_lower_bound;
2809 		logged |= 2;
2810 	}
2811 	if (rack->rc_gp_timely_dec_cnt < 0x7) {
2812 		rack->rc_gp_timely_dec_cnt++;
2813 		if (rack_timely_dec_clear &&
2814 		    (rack->rc_gp_timely_dec_cnt == rack_timely_dec_clear))
2815 			rack->rc_gp_timely_dec_cnt = 0;
2816 	}
2817 	logvar = ss_red;
2818 	logvar <<= 32;
2819 	logvar |= ca_red;
2820 	rack_log_timely(rack,  logged, rec_red, rack_per_lower_bound, logvar,
2821 			__LINE__, 2);
2822 }
2823 
2824 static void
2825 rack_log_rtt_shrinks(struct tcp_rack *rack, uint32_t us_cts,
2826 		     uint32_t rtt, uint32_t line, uint8_t reas)
2827 {
2828 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2829 		union tcp_log_stackspecific log;
2830 		struct timeval tv;
2831 
2832 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
2833 		log.u_bbr.flex1 = line;
2834 		log.u_bbr.flex2 = rack->r_ctl.rc_time_probertt_starts;
2835 		log.u_bbr.flex3 = rack->r_ctl.rc_lower_rtt_us_cts;
2836 		log.u_bbr.flex4 = rack->r_ctl.rack_per_of_gp_ss;
2837 		log.u_bbr.flex5 = rtt;
2838 		log.u_bbr.flex6 = rack->rc_highly_buffered;
2839 		log.u_bbr.flex6 <<= 1;
2840 		log.u_bbr.flex6 |= rack->forced_ack;
2841 		log.u_bbr.flex6 <<= 1;
2842 		log.u_bbr.flex6 |= rack->rc_gp_dyn_mul;
2843 		log.u_bbr.flex6 <<= 1;
2844 		log.u_bbr.flex6 |= rack->in_probe_rtt;
2845 		log.u_bbr.flex6 <<= 1;
2846 		log.u_bbr.flex6 |= rack->measure_saw_probe_rtt;
2847 		log.u_bbr.flex7 = rack->r_ctl.rack_per_of_gp_probertt;
2848 		log.u_bbr.pacing_gain = rack->r_ctl.rack_per_of_gp_ca;
2849 		log.u_bbr.cwnd_gain = rack->r_ctl.rack_per_of_gp_rec;
2850 		log.u_bbr.flex8 = reas;
2851 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
2852 		log.u_bbr.delRate = rack_get_bw(rack);
2853 		log.u_bbr.cur_del_rate = rack->r_ctl.rc_highest_us_rtt;
2854 		log.u_bbr.cur_del_rate <<= 32;
2855 		log.u_bbr.cur_del_rate |= rack->r_ctl.rc_lowest_us_rtt;
2856 		log.u_bbr.applimited = rack->r_ctl.rc_time_probertt_entered;
2857 		log.u_bbr.pkts_out = rack->r_ctl.rc_rtt_diff;
2858 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
2859 		log.u_bbr.epoch = rack->r_ctl.rc_gp_srtt;
2860 		log.u_bbr.lt_epoch = rack->r_ctl.rc_prev_gp_srtt;
2861 		log.u_bbr.pkt_epoch = rack->r_ctl.rc_lower_rtt_us_cts;
2862 		log.u_bbr.delivered = rack->r_ctl.rc_target_probertt_flight;
2863 		log.u_bbr.lost = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
2864 		log.u_bbr.rttProp = us_cts;
2865 		log.u_bbr.rttProp <<= 32;
2866 		log.u_bbr.rttProp |= rack->r_ctl.rc_entry_gp_rtt;
2867 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
2868 		    &rack->rc_inp->inp_socket->so_rcv,
2869 		    &rack->rc_inp->inp_socket->so_snd,
2870 		    BBR_LOG_RTT_SHRINKS, 0,
2871 		    0, &log, false, &rack->r_ctl.act_rcv_time);
2872 	}
2873 }
2874 
2875 static void
2876 rack_set_prtt_target(struct tcp_rack *rack, uint32_t segsiz, uint32_t rtt)
2877 {
2878 	uint64_t bwdp;
2879 
2880 	bwdp = rack_get_bw(rack);
2881 	bwdp *= (uint64_t)rtt;
2882 	bwdp /= (uint64_t)HPTS_USEC_IN_SEC;
2883 	rack->r_ctl.rc_target_probertt_flight = roundup((uint32_t)bwdp, segsiz);
2884 	if (rack->r_ctl.rc_target_probertt_flight < (segsiz * rack_timely_min_segs)) {
2885 		/*
2886 		 * A window protocol must be able to have 4 packets
2887 		 * outstanding as the floor in order to function
2888 		 * (especially considering delayed ack :D).
2889 		 */
2890 		rack->r_ctl.rc_target_probertt_flight = (segsiz * rack_timely_min_segs);
2891 	}
2892 }
2893 
2894 static void
2895 rack_enter_probertt(struct tcp_rack *rack, uint32_t us_cts)
2896 {
2897 	/**
2898 	 * ProbeRTT is a bit different in rack_pacing than in
2899 	 * BBR. It is like BBR in that it uses the lowering of
2900 	 * the RTT as a signal that we saw something new and
2901 	 * counts from there for how long between. But it is
2902 	 * different in that its quite simple. It does not
2903 	 * play with the cwnd and wait until we get down
2904 	 * to N segments outstanding and hold that for
2905 	 * 200ms. Instead it just sets the pacing reduction
2906 	 * rate to a set percentage (70 by default) and hold
2907 	 * that for a number of recent GP Srtt's.
2908 	 */
2909 	uint32_t segsiz;
2910 
2911 	if (rack->rc_gp_dyn_mul == 0)
2912 		return;
2913 
2914 	if (rack->rc_tp->snd_max == rack->rc_tp->snd_una) {
2915 		/* We are idle */
2916 		return;
2917 	}
2918 	if ((rack->rc_tp->t_flags & TF_GPUTINPROG) &&
2919 	    SEQ_GT(rack->rc_tp->snd_una, rack->rc_tp->gput_seq)) {
2920 		/*
2921 		 * Stop the goodput now, the idea here is
2922 		 * that future measurements with in_probe_rtt
2923 		 * won't register if they are not greater so
2924 		 * we want to get what info (if any) is available
2925 		 * now.
2926 		 */
2927 		rack_do_goodput_measurement(rack->rc_tp, rack,
2928 					    rack->rc_tp->snd_una, __LINE__);
2929 	}
2930 	rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt;
2931 	rack->r_ctl.rc_time_probertt_entered = us_cts;
2932 	segsiz = min(ctf_fixed_maxseg(rack->rc_tp),
2933 		     rack->r_ctl.rc_pace_min_segs);
2934 	rack->in_probe_rtt = 1;
2935 	rack->measure_saw_probe_rtt = 1;
2936 	rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
2937 	rack->r_ctl.rc_time_probertt_starts = 0;
2938 	rack->r_ctl.rc_entry_gp_rtt = rack->r_ctl.rc_gp_srtt;
2939 	if (rack_probertt_use_min_rtt_entry)
2940 		rack_set_prtt_target(rack, segsiz, get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt));
2941 	else
2942 		rack_set_prtt_target(rack, segsiz, rack->r_ctl.rc_gp_srtt);
2943 	rack_log_rtt_shrinks(rack,  us_cts,  get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
2944 			     __LINE__, RACK_RTTS_ENTERPROBE);
2945 }
2946 
2947 static void
2948 rack_exit_probertt(struct tcp_rack *rack, uint32_t us_cts)
2949 {
2950 	struct rack_sendmap *rsm;
2951 	uint32_t segsiz;
2952 
2953 	segsiz = min(ctf_fixed_maxseg(rack->rc_tp),
2954 		     rack->r_ctl.rc_pace_min_segs);
2955 	rack->in_probe_rtt = 0;
2956 	if ((rack->rc_tp->t_flags & TF_GPUTINPROG) &&
2957 	    SEQ_GT(rack->rc_tp->snd_una, rack->rc_tp->gput_seq)) {
2958 		/*
2959 		 * Stop the goodput now, the idea here is
2960 		 * that future measurements with in_probe_rtt
2961 		 * won't register if they are not greater so
2962 		 * we want to get what info (if any) is available
2963 		 * now.
2964 		 */
2965 		rack_do_goodput_measurement(rack->rc_tp, rack,
2966 					    rack->rc_tp->snd_una, __LINE__);
2967 	} else if (rack->rc_tp->t_flags & TF_GPUTINPROG) {
2968 		/*
2969 		 * We don't have enough data to make a measurement.
2970 		 * So lets just stop and start here after exiting
2971 		 * probe-rtt. We probably are not interested in
2972 		 * the results anyway.
2973 		 */
2974 		rack->rc_tp->t_flags &= ~TF_GPUTINPROG;
2975 	}
2976 	/*
2977 	 * Measurements through the current snd_max are going
2978 	 * to be limited by the slower pacing rate.
2979 	 *
2980 	 * We need to mark these as app-limited so we
2981 	 * don't collapse the b/w.
2982 	 */
2983 	rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
2984 	if (rsm && ((rsm->r_flags & RACK_APP_LIMITED) == 0)) {
2985 		if (rack->r_ctl.rc_app_limited_cnt == 0)
2986 			rack->r_ctl.rc_end_appl = rack->r_ctl.rc_first_appl = rsm;
2987 		else {
2988 			/*
2989 			 * Go out to the end app limited and mark
2990 			 * this new one as next and move the end_appl up
2991 			 * to this guy.
2992 			 */
2993 			if (rack->r_ctl.rc_end_appl)
2994 				rack->r_ctl.rc_end_appl->r_nseq_appl = rsm->r_start;
2995 			rack->r_ctl.rc_end_appl = rsm;
2996 		}
2997 		rsm->r_flags |= RACK_APP_LIMITED;
2998 		rack->r_ctl.rc_app_limited_cnt++;
2999 	}
3000 	/*
3001 	 * Now, we need to examine our pacing rate multipliers.
3002 	 * If its under 100%, we need to kick it back up to
3003 	 * 100%. We also don't let it be over our "max" above
3004 	 * the actual rate i.e. 100% + rack_clamp_atexit_prtt.
3005 	 * Note setting clamp_atexit_prtt to 0 has the effect
3006 	 * of setting CA/SS to 100% always at exit (which is
3007 	 * the default behavior).
3008 	 */
3009 	if (rack_probertt_clear_is) {
3010 		rack->rc_gp_incr = 0;
3011 		rack->rc_gp_bwred = 0;
3012 		rack->rc_gp_timely_inc_cnt = 0;
3013 		rack->rc_gp_timely_dec_cnt = 0;
3014 	}
3015 	/* Do we do any clamping at exit? */
3016 	if (rack->rc_highly_buffered && rack_atexit_prtt_hbp) {
3017 		rack->r_ctl.rack_per_of_gp_ca = rack_atexit_prtt_hbp;
3018 		rack->r_ctl.rack_per_of_gp_ss = rack_atexit_prtt_hbp;
3019 	}
3020 	if ((rack->rc_highly_buffered == 0) && rack_atexit_prtt) {
3021 		rack->r_ctl.rack_per_of_gp_ca = rack_atexit_prtt;
3022 		rack->r_ctl.rack_per_of_gp_ss = rack_atexit_prtt;
3023 	}
3024 	/*
3025 	 * Lets set rtt_diff to 0, so that we will get a "boost"
3026 	 * after exiting.
3027 	 */
3028 	rack->r_ctl.rc_rtt_diff = 0;
3029 
3030 	/* Clear all flags so we start fresh */
3031 	rack->rc_tp->t_bytes_acked = 0;
3032 	rack->rc_tp->ccv->flags &= ~CCF_ABC_SENTAWND;
3033 	/*
3034 	 * If configured to, set the cwnd and ssthresh to
3035 	 * our targets.
3036 	 */
3037 	if (rack_probe_rtt_sets_cwnd) {
3038 		uint64_t ebdp;
3039 		uint32_t setto;
3040 
3041 		/* Set ssthresh so we get into CA once we hit our target */
3042 		if (rack_probertt_use_min_rtt_exit == 1) {
3043 			/* Set to min rtt */
3044 			rack_set_prtt_target(rack, segsiz,
3045 					     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt));
3046 		} else if (rack_probertt_use_min_rtt_exit == 2) {
3047 			/* Set to current gp rtt */
3048 			rack_set_prtt_target(rack, segsiz,
3049 					     rack->r_ctl.rc_gp_srtt);
3050 		} else if (rack_probertt_use_min_rtt_exit == 3) {
3051 			/* Set to entry gp rtt */
3052 			rack_set_prtt_target(rack, segsiz,
3053 					     rack->r_ctl.rc_entry_gp_rtt);
3054 		} else  {
3055 			uint64_t sum;
3056 			uint32_t setval;
3057 
3058 			sum = rack->r_ctl.rc_entry_gp_rtt;
3059 			sum *= 10;
3060 			sum /= (uint64_t)(max(1, rack->r_ctl.rc_gp_srtt));
3061 			if (sum >= 20) {
3062 				/*
3063 				 * A highly buffered path needs
3064 				 * cwnd space for timely to work.
3065 				 * Lets set things up as if
3066 				 * we are heading back here again.
3067 				 */
3068 				setval = rack->r_ctl.rc_entry_gp_rtt;
3069 			} else if (sum >= 15) {
3070 				/*
3071 				 * Lets take the smaller of the
3072 				 * two since we are just somewhat
3073 				 * buffered.
3074 				 */
3075 				setval = rack->r_ctl.rc_gp_srtt;
3076 				if (setval > rack->r_ctl.rc_entry_gp_rtt)
3077 					setval = rack->r_ctl.rc_entry_gp_rtt;
3078 			} else {
3079 				/*
3080 				 * Here we are not highly buffered
3081 				 * and should pick the min we can to
3082 				 * keep from causing loss.
3083 				 */
3084 				setval = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
3085 			}
3086 			rack_set_prtt_target(rack, segsiz,
3087 					     setval);
3088 		}
3089 		if (rack_probe_rtt_sets_cwnd > 1) {
3090 			/* There is a percentage here to boost */
3091 			ebdp = rack->r_ctl.rc_target_probertt_flight;
3092 			ebdp *= rack_probe_rtt_sets_cwnd;
3093 			ebdp /= 100;
3094 			setto = rack->r_ctl.rc_target_probertt_flight + ebdp;
3095 		} else
3096 			setto = rack->r_ctl.rc_target_probertt_flight;
3097 		rack->rc_tp->snd_cwnd = roundup(setto, segsiz);
3098 		if (rack->rc_tp->snd_cwnd < (segsiz * rack_timely_min_segs)) {
3099 			/* Enforce a min */
3100 			rack->rc_tp->snd_cwnd = segsiz * rack_timely_min_segs;
3101 		}
3102 		/* If we set in the cwnd also set the ssthresh point so we are in CA */
3103 		rack->rc_tp->snd_ssthresh = (rack->rc_tp->snd_cwnd - 1);
3104 	}
3105 	rack_log_rtt_shrinks(rack,  us_cts,
3106 			     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3107 			     __LINE__, RACK_RTTS_EXITPROBE);
3108 	/* Clear times last so log has all the info */
3109 	rack->r_ctl.rc_probertt_sndmax_atexit = rack->rc_tp->snd_max;
3110 	rack->r_ctl.rc_time_probertt_entered = us_cts;
3111 	rack->r_ctl.rc_time_probertt_starts = rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
3112 	rack->r_ctl.rc_time_of_last_probertt = us_cts;
3113 }
3114 
3115 static void
3116 rack_check_probe_rtt(struct tcp_rack *rack, uint32_t us_cts)
3117 {
3118 	/* Check in on probe-rtt */
3119 	if (rack->rc_gp_filled == 0) {
3120 		/* We do not do p-rtt unless we have gp measurements */
3121 		return;
3122 	}
3123 	if (rack->in_probe_rtt) {
3124 		uint64_t no_overflow;
3125 		uint32_t endtime, must_stay;
3126 
3127 		if (rack->r_ctl.rc_went_idle_time &&
3128 		    ((us_cts - rack->r_ctl.rc_went_idle_time) > rack_min_probertt_hold)) {
3129 			/*
3130 			 * We went idle during prtt, just exit now.
3131 			 */
3132 			rack_exit_probertt(rack, us_cts);
3133 		} else if (rack_probe_rtt_safety_val &&
3134 		    TSTMP_GT(us_cts, rack->r_ctl.rc_time_probertt_entered) &&
3135 		    ((us_cts - rack->r_ctl.rc_time_probertt_entered) > rack_probe_rtt_safety_val)) {
3136 			/*
3137 			 * Probe RTT safety value triggered!
3138 			 */
3139 			rack_log_rtt_shrinks(rack,  us_cts,
3140 					     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3141 					     __LINE__, RACK_RTTS_SAFETY);
3142 			rack_exit_probertt(rack, us_cts);
3143 		}
3144 		/* Calculate the max we will wait */
3145 		endtime = rack->r_ctl.rc_time_probertt_entered + (rack->r_ctl.rc_gp_srtt * rack_max_drain_wait);
3146 		if (rack->rc_highly_buffered)
3147 			endtime += (rack->r_ctl.rc_gp_srtt * rack_max_drain_hbp);
3148 		/* Calculate the min we must wait */
3149 		must_stay = rack->r_ctl.rc_time_probertt_entered + (rack->r_ctl.rc_gp_srtt * rack_must_drain);
3150 		if ((ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) > rack->r_ctl.rc_target_probertt_flight) &&
3151 		    TSTMP_LT(us_cts, endtime)) {
3152 			uint32_t calc;
3153 			/* Do we lower more? */
3154 no_exit:
3155 			if (TSTMP_GT(us_cts, rack->r_ctl.rc_time_probertt_entered))
3156 				calc = us_cts - rack->r_ctl.rc_time_probertt_entered;
3157 			else
3158 				calc = 0;
3159 			calc /= max(rack->r_ctl.rc_gp_srtt, 1);
3160 			if (calc) {
3161 				/* Maybe */
3162 				calc *= rack_per_of_gp_probertt_reduce;
3163 				rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt - calc;
3164 				/* Limit it too */
3165 				if (rack->r_ctl.rack_per_of_gp_probertt < rack_per_of_gp_lowthresh)
3166 					rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_lowthresh;
3167 			}
3168 			/* We must reach target or the time set */
3169 			return;
3170 		}
3171 		if (rack->r_ctl.rc_time_probertt_starts == 0) {
3172 			if ((TSTMP_LT(us_cts, must_stay) &&
3173 			     rack->rc_highly_buffered) ||
3174 			     (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) >
3175 			      rack->r_ctl.rc_target_probertt_flight)) {
3176 				/* We are not past the must_stay time */
3177 				goto no_exit;
3178 			}
3179 			rack_log_rtt_shrinks(rack,  us_cts,
3180 					     get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3181 					     __LINE__, RACK_RTTS_REACHTARGET);
3182 			rack->r_ctl.rc_time_probertt_starts = us_cts;
3183 			if (rack->r_ctl.rc_time_probertt_starts == 0)
3184 				rack->r_ctl.rc_time_probertt_starts = 1;
3185 			/* Restore back to our rate we want to pace at in prtt */
3186 			rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt;
3187 		}
3188 		/*
3189 		 * Setup our end time, some number of gp_srtts plus 200ms.
3190 		 */
3191 		no_overflow = ((uint64_t)rack->r_ctl.rc_gp_srtt *
3192 			       (uint64_t)rack_probertt_gpsrtt_cnt_mul);
3193 		if (rack_probertt_gpsrtt_cnt_div)
3194 			endtime = (uint32_t)(no_overflow / (uint64_t)rack_probertt_gpsrtt_cnt_div);
3195 		else
3196 			endtime = 0;
3197 		endtime += rack_min_probertt_hold;
3198 		endtime += rack->r_ctl.rc_time_probertt_starts;
3199 		if (TSTMP_GEQ(us_cts,  endtime)) {
3200 			/* yes, exit probertt  */
3201 			rack_exit_probertt(rack, us_cts);
3202  		}
3203 
3204 	} else 	if((us_cts - rack->r_ctl.rc_lower_rtt_us_cts) >= rack_time_between_probertt) {
3205 		/* Go into probertt, its been too long since we went lower  */
3206 		rack_enter_probertt(rack, us_cts);
3207 	}
3208 }
3209 
3210 static void
3211 rack_update_multiplier(struct tcp_rack *rack, int32_t timely_says, uint64_t last_bw_est,
3212 		       uint32_t rtt, int32_t rtt_diff)
3213 {
3214 	uint64_t cur_bw, up_bnd, low_bnd, subfr;
3215 	uint32_t losses;
3216 
3217 	if ((rack->rc_gp_dyn_mul == 0) ||
3218 	    (rack->use_fixed_rate) ||
3219 	    (rack->in_probe_rtt) ||
3220 	    (rack->rc_always_pace == 0)) {
3221 		/* No dynamic GP multipler in play */
3222 		return;
3223 	}
3224 	losses = rack->r_ctl.rc_loss_count - rack->r_ctl.rc_loss_at_start;
3225 	cur_bw = rack_get_bw(rack);
3226 	/* Calculate our up and down range */
3227 	up_bnd = rack->r_ctl.last_gp_comp_bw * (uint64_t)rack_gp_per_bw_mul_up;
3228 	up_bnd /= 100;
3229 	up_bnd += rack->r_ctl.last_gp_comp_bw;
3230 
3231 	subfr = (uint64_t)rack->r_ctl.last_gp_comp_bw * (uint64_t)rack_gp_per_bw_mul_down;
3232 	subfr /= 100;
3233 	low_bnd = rack->r_ctl.last_gp_comp_bw - subfr;
3234 	if ((timely_says == 2) && (rack->r_ctl.rc_no_push_at_mrtt)) {
3235 		/*
3236 		 * This is the case where our RTT is above
3237 		 * the max target and we have been configured
3238 		 * to just do timely no bonus up stuff in that case.
3239 		 *
3240 		 * There are two configurations, set to 1, and we
3241 		 * just do timely if we are over our max. If its
3242 		 * set above 1 then we slam the multipliers down
3243 		 * to 100 and then decrement per timely.
3244 		 */
3245 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
3246 				__LINE__, 3);
3247 		if (rack->r_ctl.rc_no_push_at_mrtt > 1)
3248 			rack_validate_multipliers_at_or_below_100(rack);
3249 		rack_decrease_bw_mul(rack, timely_says, rtt, rtt_diff);
3250 	} else if ((last_bw_est < low_bnd) && !losses) {
3251 		/*
3252 		 * We are decreasing this is a bit complicated this
3253 		 * means we are loosing ground. This could be
3254 		 * because another flow entered and we are competing
3255 		 * for b/w with it. This will push the RTT up which
3256 		 * makes timely unusable unless we want to get shoved
3257 		 * into a corner and just be backed off (the age
3258 		 * old problem with delay based CC).
3259 		 *
3260 		 * On the other hand if it was a route change we
3261 		 * would like to stay somewhat contained and not
3262 		 * blow out the buffers.
3263 		 */
3264 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
3265 				__LINE__, 3);
3266 		rack->r_ctl.last_gp_comp_bw = cur_bw;
3267 		if (rack->rc_gp_bwred == 0) {
3268 			/* Go into reduction counting */
3269 			rack->rc_gp_bwred = 1;
3270 			rack->rc_gp_timely_dec_cnt = 0;
3271 		}
3272 		if ((rack->rc_gp_timely_dec_cnt < rack_timely_max_push_drop) ||
3273 		    (timely_says == 0)) {
3274 			/*
3275 			 * Push another time with a faster pacing
3276 			 * to try to gain back (we include override to
3277 			 * get a full raise factor).
3278 			 */
3279 			if ((rack->rc_gp_saw_ca && rack->r_ctl.rack_per_of_gp_ca <= rack_down_raise_thresh) ||
3280 			    (rack->rc_gp_saw_ss && rack->r_ctl.rack_per_of_gp_ss <= rack_down_raise_thresh) ||
3281 			    (timely_says == 0) ||
3282 			    (rack_down_raise_thresh == 0)) {
3283 				/*
3284 				 * Do an override up in b/w if we were
3285 				 * below the threshold or if the threshold
3286 				 * is zero we always do the raise.
3287 				 */
3288 				rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 1);
3289 			} else {
3290 				/* Log it stays the same */
3291 				rack_log_timely(rack,  0, last_bw_est, low_bnd, 0,
3292 						__LINE__, 11);
3293 			}
3294 			rack->rc_gp_timely_dec_cnt++;
3295 			/* We are not incrementing really no-count */
3296 			rack->rc_gp_incr = 0;
3297 			rack->rc_gp_timely_inc_cnt = 0;
3298 		} else {
3299 			/*
3300 			 * Lets just use the RTT
3301 			 * information and give up
3302 			 * pushing.
3303 			 */
3304 			goto use_timely;
3305 		}
3306 	}  else if ((timely_says != 2) &&
3307 		    !losses &&
3308 		    (last_bw_est > up_bnd)) {
3309 		/*
3310 		 * We are increasing b/w lets keep going, updating
3311 		 * our b/w and ignoring any timely input, unless
3312 		 * of course we are at our max raise (if there is one).
3313 		 */
3314 
3315 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
3316 				__LINE__, 3);
3317 		rack->r_ctl.last_gp_comp_bw = cur_bw;
3318 		if (rack->rc_gp_saw_ss &&
3319 		    rack_per_upper_bound_ss &&
3320 		     (rack->r_ctl.rack_per_of_gp_ss == rack_per_upper_bound_ss)) {
3321 			    /*
3322 			     * In cases where we can't go higher
3323 			     * we should just use timely.
3324 			     */
3325 			    goto use_timely;
3326 		}
3327 		if (rack->rc_gp_saw_ca &&
3328 		    rack_per_upper_bound_ca &&
3329 		    (rack->r_ctl.rack_per_of_gp_ca == rack_per_upper_bound_ca)) {
3330 			    /*
3331 			     * In cases where we can't go higher
3332 			     * we should just use timely.
3333 			     */
3334 			    goto use_timely;
3335 		}
3336 		rack->rc_gp_bwred = 0;
3337 		rack->rc_gp_timely_dec_cnt = 0;
3338 		/* You get a set number of pushes if timely is trying to reduce  */
3339 		if ((rack->rc_gp_incr < rack_timely_max_push_rise) || (timely_says == 0)) {
3340 			rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 0);
3341 		} else {
3342  			/* Log it stays the same */
3343 			rack_log_timely(rack,  0, last_bw_est, up_bnd, 0,
3344 			    __LINE__, 12);
3345 		}
3346 		return;
3347 	} else {
3348 		/*
3349 		 * We are staying between the lower and upper range bounds
3350 		 * so use timely to decide.
3351 		 */
3352 		rack_log_timely(rack,  timely_says, cur_bw, low_bnd, up_bnd,
3353 				__LINE__, 3);
3354 use_timely:
3355 		if (timely_says) {
3356 			rack->rc_gp_incr = 0;
3357 			rack->rc_gp_timely_inc_cnt = 0;
3358 			if ((rack->rc_gp_timely_dec_cnt < rack_timely_max_push_drop) &&
3359 			    !losses &&
3360 			    (last_bw_est < low_bnd)) {
3361 				/* We are loosing ground */
3362 				rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 0);
3363 				rack->rc_gp_timely_dec_cnt++;
3364 				/* We are not incrementing really no-count */
3365 				rack->rc_gp_incr = 0;
3366 				rack->rc_gp_timely_inc_cnt = 0;
3367 			} else
3368 				rack_decrease_bw_mul(rack, timely_says, rtt, rtt_diff);
3369 		} else  {
3370 			rack->rc_gp_bwred = 0;
3371 			rack->rc_gp_timely_dec_cnt = 0;
3372 			rack_increase_bw_mul(rack, timely_says, cur_bw, last_bw_est, 0);
3373 		}
3374 	}
3375 }
3376 
3377 static int32_t
3378 rack_make_timely_judgement(struct tcp_rack *rack, uint32_t rtt, int32_t rtt_diff, uint32_t prev_rtt)
3379 {
3380 	int32_t timely_says;
3381 	uint64_t log_mult, log_rtt_a_diff;
3382 
3383 	log_rtt_a_diff = rtt;
3384 	log_rtt_a_diff <<= 32;
3385 	log_rtt_a_diff |= (uint32_t)rtt_diff;
3386 	if (rtt >= (get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) *
3387 		    rack_gp_rtt_maxmul)) {
3388 		/* Reduce the b/w multipler */
3389 		timely_says = 2;
3390 		log_mult = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_maxmul;
3391 		log_mult <<= 32;
3392 		log_mult |= prev_rtt;
3393 		rack_log_timely(rack,  timely_says, log_mult,
3394 				get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3395 				log_rtt_a_diff, __LINE__, 4);
3396 	} else if (rtt <= (get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) +
3397 			   ((get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_minmul) /
3398 			    max(rack_gp_rtt_mindiv , 1)))) {
3399 		/* Increase the b/w multipler */
3400 		log_mult = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) +
3401 			((get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack_gp_rtt_minmul) /
3402 			 max(rack_gp_rtt_mindiv , 1));
3403 		log_mult <<= 32;
3404 		log_mult |= prev_rtt;
3405 		timely_says = 0;
3406 		rack_log_timely(rack,  timely_says, log_mult ,
3407 				get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt),
3408 				log_rtt_a_diff, __LINE__, 5);
3409 	} else {
3410 		/*
3411 		 * Use a gradient to find it the timely gradient
3412 		 * is:
3413 		 * grad = rc_rtt_diff / min_rtt;
3414 		 *
3415 		 * anything below or equal to 0 will be
3416 		 * a increase indication. Anything above
3417 		 * zero is a decrease. Note we take care
3418 		 * of the actual gradient calculation
3419 		 * in the reduction (its not needed for
3420 		 * increase).
3421 		 */
3422 		log_mult = prev_rtt;
3423 		if (rtt_diff <= 0) {
3424 			/*
3425 			 * Rttdiff is less than zero, increase the
3426 			 * b/w multipler (its 0 or negative)
3427 			 */
3428 			timely_says = 0;
3429 			rack_log_timely(rack,  timely_says, log_mult,
3430 					get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt), log_rtt_a_diff, __LINE__, 6);
3431 		} else {
3432 			/* Reduce the b/w multipler */
3433 			timely_says = 1;
3434 			rack_log_timely(rack,  timely_says, log_mult,
3435 					get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt), log_rtt_a_diff, __LINE__, 7);
3436 		}
3437 	}
3438 	return (timely_says);
3439 }
3440 
3441 static void
3442 rack_do_goodput_measurement(struct tcpcb *tp, struct tcp_rack *rack,
3443 			    tcp_seq th_ack, int line)
3444 {
3445 	uint64_t tim, bytes_ps, ltim, stim, utim;
3446 	uint32_t segsiz, bytes, reqbytes, us_cts;
3447 	int32_t gput, new_rtt_diff, timely_says;
3448 
3449 	us_cts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
3450 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
3451 	if (TSTMP_GEQ(us_cts, tp->gput_ts))
3452 		tim = us_cts - tp->gput_ts;
3453 	else
3454 		tim = 0;
3455 
3456 	if (TSTMP_GT(rack->r_ctl.rc_gp_cumack_ts, rack->r_ctl.rc_gp_output_ts))
3457 		stim = rack->r_ctl.rc_gp_cumack_ts - rack->r_ctl.rc_gp_output_ts;
3458 	else
3459 		stim = 0;
3460 	/*
3461 	 * Use the larger of the send time or ack time. This prevents us
3462 	 * from being influenced by ack artifacts to come up with too
3463 	 * high of measurement. Note that since we are spanning over many more
3464 	 * bytes in most of our measurements hopefully that is less likely to
3465 	 * occur.
3466 	 */
3467 	if (tim > stim)
3468 		utim = max(tim, 1);
3469 	else
3470 		utim = max(stim, 1);
3471 	/* Lets validate utim */
3472 	ltim = max(1, (utim/HPTS_USEC_IN_MSEC));
3473 	gput = (((uint64_t) (th_ack - tp->gput_seq)) << 3) / ltim;
3474 	reqbytes = min(rc_init_window(rack), (MIN_GP_WIN * segsiz));
3475 	if ((tim == 0) && (stim == 0)) {
3476 		/*
3477 		 * Invalid measurement time, maybe
3478 		 * all on one ack/one send?
3479 		 */
3480 		bytes = 0;
3481 		bytes_ps = 0;
3482 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
3483 					   0, 0, 0, 10, __LINE__, NULL);
3484 		goto skip_measurement;
3485 	}
3486 	if (rack->r_ctl.rc_gp_lowrtt == 0xffffffff) {
3487 		/* We never made a us_rtt measurement? */
3488 		bytes = 0;
3489 		bytes_ps = 0;
3490 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
3491 					   0, 0, 0, 10, __LINE__, NULL);
3492 		goto skip_measurement;
3493 	}
3494 	/*
3495 	 * Calculate the maximum possible b/w this connection
3496 	 * could have. We base our calculation on the lowest
3497 	 * rtt we have seen during the measurement and the
3498 	 * largest rwnd the client has given us in that time. This
3499 	 * forms a BDP that is the maximum that we could ever
3500 	 * get to the client. Anything larger is not valid.
3501 	 *
3502 	 * I originally had code here that rejected measurements
3503 	 * where the time was less than 1/2 the latest us_rtt.
3504 	 * But after thinking on that I realized its wrong since
3505 	 * say you had a 150Mbps or even 1Gbps link, and you
3506 	 * were a long way away.. example I am in Europe (100ms rtt)
3507 	 * talking to my 1Gbps link in S.C. Now measuring say 150,000
3508 	 * bytes my time would be 1.2ms, and yet my rtt would say
3509 	 * the measurement was invalid the time was < 50ms. The
3510 	 * same thing is true for 150Mb (8ms of time).
3511 	 *
3512 	 * A better way I realized is to look at what the maximum
3513 	 * the connection could possibly do. This is gated on
3514 	 * the lowest RTT we have seen and the highest rwnd.
3515 	 * We should in theory never exceed that, if we are
3516 	 * then something on the path is storing up packets
3517 	 * and then feeding them all at once to our endpoint
3518 	 * messing up our measurement.
3519 	 */
3520 	rack->r_ctl.last_max_bw = rack->r_ctl.rc_gp_high_rwnd;
3521 	rack->r_ctl.last_max_bw *= HPTS_USEC_IN_SEC;
3522 	rack->r_ctl.last_max_bw /= rack->r_ctl.rc_gp_lowrtt;
3523 	if (SEQ_LT(th_ack, tp->gput_seq)) {
3524 		/* No measurement can be made */
3525 		bytes = 0;
3526 		bytes_ps = 0;
3527 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
3528 					   0, 0, 0, 10, __LINE__, NULL);
3529 		goto skip_measurement;
3530 	} else
3531 		bytes = (th_ack - tp->gput_seq);
3532 	bytes_ps = (uint64_t)bytes;
3533 	/*
3534 	 * Don't measure a b/w for pacing unless we have gotten at least
3535 	 * an initial windows worth of data in this measurement interval.
3536 	 *
3537 	 * Small numbers of bytes get badly influenced by delayed ack and
3538 	 * other artifacts. Note we take the initial window or our
3539 	 * defined minimum GP (defaulting to 10 which hopefully is the
3540 	 * IW).
3541 	 */
3542 	if (rack->rc_gp_filled == 0) {
3543 		/*
3544 		 * The initial estimate is special. We
3545 		 * have blasted out an IW worth of packets
3546 		 * without a real valid ack ts results. We
3547 		 * then setup the app_limited_needs_set flag,
3548 		 * this should get the first ack in (probably 2
3549 		 * MSS worth) to be recorded as the timestamp.
3550 		 * We thus allow a smaller number of bytes i.e.
3551 		 * IW - 2MSS.
3552 		 */
3553 		reqbytes -= (2 * segsiz);
3554 		/* Also lets fill previous for our first measurement to be neutral */
3555 		rack->r_ctl.rc_prev_gp_srtt = rack->r_ctl.rc_gp_srtt;
3556 	}
3557 	if ((bytes_ps < reqbytes) || rack->app_limited_needs_set) {
3558 		rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
3559 					   rack->r_ctl.rc_app_limited_cnt,
3560 					   0, 0, 10, __LINE__, NULL);
3561 		goto skip_measurement;
3562 	}
3563 	/*
3564 	 * We now need to calculate the Timely like status so
3565 	 * we can update (possibly) the b/w multipliers.
3566 	 */
3567 	new_rtt_diff = (int32_t)rack->r_ctl.rc_gp_srtt - (int32_t)rack->r_ctl.rc_prev_gp_srtt;
3568 	if (rack->rc_gp_filled == 0) {
3569 		/* No previous reading */
3570 		rack->r_ctl.rc_rtt_diff = new_rtt_diff;
3571 	} else {
3572 		if (rack->measure_saw_probe_rtt == 0) {
3573 			/*
3574 			 * We don't want a probertt to be counted
3575 			 * since it will be negative incorrectly. We
3576 			 * expect to be reducing the RTT when we
3577 			 * pace at a slower rate.
3578 			 */
3579 			rack->r_ctl.rc_rtt_diff -= (rack->r_ctl.rc_rtt_diff / 8);
3580 			rack->r_ctl.rc_rtt_diff += (new_rtt_diff / 8);
3581 		}
3582 	}
3583 	timely_says = rack_make_timely_judgement(rack,
3584 		rack->r_ctl.rc_gp_srtt,
3585 		rack->r_ctl.rc_rtt_diff,
3586 	        rack->r_ctl.rc_prev_gp_srtt
3587 		);
3588 	bytes_ps *= HPTS_USEC_IN_SEC;
3589 	bytes_ps /= utim;
3590 	if (bytes_ps > rack->r_ctl.last_max_bw) {
3591 		/*
3592 		 * Something is on path playing
3593 		 * since this b/w is not possible based
3594 		 * on our BDP (highest rwnd and lowest rtt
3595 		 * we saw in the measurement window).
3596 		 *
3597 		 * Another option here would be to
3598 		 * instead skip the measurement.
3599 		 */
3600 		rack_log_pacing_delay_calc(rack, bytes, reqbytes,
3601 					   bytes_ps, rack->r_ctl.last_max_bw, 0,
3602 					   11, __LINE__, NULL);
3603 		bytes_ps = rack->r_ctl.last_max_bw;
3604 	}
3605 	/* We store gp for b/w in bytes per second  */
3606 	if (rack->rc_gp_filled == 0) {
3607 		/* Initial measurment */
3608 		if (bytes_ps) {
3609 			rack->r_ctl.gp_bw = bytes_ps;
3610 			rack->rc_gp_filled = 1;
3611 			rack->r_ctl.num_avg = 1;
3612 			rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
3613 		} else {
3614 			rack_log_pacing_delay_calc(rack, bytes_ps, reqbytes,
3615 						   rack->r_ctl.rc_app_limited_cnt,
3616 						   0, 0, 10, __LINE__, NULL);
3617 		}
3618 		if (rack->rc_inp->inp_in_hpts &&
3619 		    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
3620 			/*
3621 			 * Ok we can't trust the pacer in this case
3622 			 * where we transition from un-paced to paced.
3623 			 * Or for that matter when the burst mitigation
3624 			 * was making a wild guess and got it wrong.
3625 			 * Stop the pacer and clear up all the aggregate
3626 			 * delays etc.
3627 			 */
3628 			tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
3629 			rack->r_ctl.rc_hpts_flags = 0;
3630 			rack->r_ctl.rc_last_output_to = 0;
3631 		}
3632 	} else if (rack->r_ctl.num_avg < RACK_REQ_AVG) {
3633 		/* Still a small number run an average */
3634 		rack->r_ctl.gp_bw += bytes_ps;
3635 		rack->r_ctl.num_avg++;
3636 		if (rack->r_ctl.num_avg >= RACK_REQ_AVG) {
3637 			/* We have collected enought to move forward */
3638 			rack->r_ctl.gp_bw /= (uint64_t)rack->r_ctl.num_avg;
3639 		}
3640 	} else {
3641 		/*
3642 		 * We want to take 1/wma of the goodput and add in to 7/8th
3643 		 * of the old value weighted by the srtt. So if your measurement
3644 		 * period is say 2 SRTT's long you would get 1/4 as the
3645 		 * value, if it was like 1/2 SRTT then you would get 1/16th.
3646 		 *
3647 		 * But we must be careful not to take too much i.e. if the
3648 		 * srtt is say 20ms and the measurement is taken over
3649 		 * 400ms our weight would be 400/20 i.e. 20. On the
3650 		 * other hand if we get a measurement over 1ms with a
3651 		 * 10ms rtt we only want to take a much smaller portion.
3652 		 */
3653 		uint64_t  resid_bw, subpart, addpart, srtt;
3654 
3655 		srtt = ((uint64_t)TICKS_2_USEC(tp->t_srtt) >> TCP_RTT_SHIFT);
3656 		if (srtt == 0) {
3657 			/*
3658 			 * Strange why did t_srtt go back to zero?
3659 			 */
3660 			if (rack->r_ctl.rc_rack_min_rtt)
3661 				srtt = (rack->r_ctl.rc_rack_min_rtt * HPTS_USEC_IN_MSEC);
3662 			else
3663 				srtt = HPTS_USEC_IN_MSEC;
3664 		}
3665 		/*
3666 		 * XXXrrs: Note for reviewers, in playing with
3667 		 * dynamic pacing I discovered this GP calculation
3668 		 * as done originally leads to some undesired results.
3669 		 * Basically you can get longer measurements contributing
3670 		 * too much to the WMA. Thus I changed it if you are doing
3671 		 * dynamic adjustments to only do the aportioned adjustment
3672 		 * if we have a very small (time wise) measurement. Longer
3673 		 * measurements just get there weight (defaulting to 1/8)
3674 		 * add to the WMA. We may want to think about changing
3675 		 * this to always do that for both sides i.e. dynamic
3676 		 * and non-dynamic... but considering lots of folks
3677 		 * were playing with this I did not want to change the
3678 		 * calculation per.se. without your thoughts.. Lawerence?
3679 		 * Peter??
3680 		 */
3681 		if (rack->rc_gp_dyn_mul == 0) {
3682 			subpart = rack->r_ctl.gp_bw * utim;
3683 			subpart /= (srtt * 8);
3684 			if (subpart < (rack->r_ctl.gp_bw / 2)) {
3685 				/*
3686 				 * The b/w update takes no more
3687 				 * away then 1/2 our running total
3688 				 * so factor it in.
3689 				 */
3690 				addpart = bytes_ps * utim;
3691 				addpart /= (srtt * 8);
3692 			} else {
3693 				/*
3694 				 * Don't allow a single measurement
3695 				 * to account for more than 1/2 of the
3696 				 * WMA. This could happen on a retransmission
3697 				 * where utim becomes huge compared to
3698 				 * srtt (multiple retransmissions when using
3699 				 * the sending rate which factors in all the
3700 				 * transmissions from the first one).
3701 				 */
3702 				subpart = rack->r_ctl.gp_bw / 2;
3703 				addpart = bytes_ps / 2;
3704 			}
3705 			resid_bw = rack->r_ctl.gp_bw - subpart;
3706 			rack->r_ctl.gp_bw = resid_bw + addpart;
3707 		} else {
3708 			if ((utim / srtt) <= 1) {
3709 				/*
3710 				 * The b/w update was over a small period
3711 				 * of time. The idea here is to prevent a small
3712 				 * measurement time period from counting
3713 				 * too much. So we scale it based on the
3714 				 * time so it attributes less than 1/rack_wma_divisor
3715 				 * of its measurement.
3716 				 */
3717 				subpart = rack->r_ctl.gp_bw * utim;
3718 				subpart /= (srtt * rack_wma_divisor);
3719 				addpart = bytes_ps * utim;
3720 				addpart /= (srtt * rack_wma_divisor);
3721 			} else {
3722 				/*
3723 				 * The scaled measurement was long
3724 				 * enough so lets just add in the
3725 				 * portion of the measurment i.e. 1/rack_wma_divisor
3726 				 */
3727 				subpart = rack->r_ctl.gp_bw / rack_wma_divisor;
3728 				addpart = bytes_ps / rack_wma_divisor;
3729 			}
3730 			if ((rack->measure_saw_probe_rtt == 0) ||
3731 		            (bytes_ps > rack->r_ctl.gp_bw)) {
3732 				/*
3733 				 * For probe-rtt we only add it in
3734 				 * if its larger, all others we just
3735 				 * add in.
3736 				 */
3737 				resid_bw = rack->r_ctl.gp_bw - subpart;
3738 				rack->r_ctl.gp_bw = resid_bw + addpart;
3739 			}
3740 		}
3741 	}
3742 	/* We do not update any multipliers if we are in or have seen a probe-rtt */
3743 	if ((rack->measure_saw_probe_rtt == 0) && rack->rc_gp_rtt_set)
3744 		rack_update_multiplier(rack, timely_says, bytes_ps,
3745 				       rack->r_ctl.rc_gp_srtt,
3746 				       rack->r_ctl.rc_rtt_diff);
3747 	rack_log_pacing_delay_calc(rack, bytes, tim, bytes_ps, stim,
3748 				   rack_get_bw(rack), 3, line, NULL);
3749 	/* reset the gp srtt and setup the new prev */
3750 	rack->r_ctl.rc_prev_gp_srtt = rack->r_ctl.rc_gp_srtt;
3751 	/* Record the lost count for the next measurement */
3752 	rack->r_ctl.rc_loss_at_start = rack->r_ctl.rc_loss_count;
3753 	/*
3754 	 * We restart our diffs based on the gpsrtt in the
3755 	 * measurement window.
3756 	 */
3757 	rack->rc_gp_rtt_set = 0;
3758 	rack->rc_gp_saw_rec = 0;
3759 	rack->rc_gp_saw_ca = 0;
3760 	rack->rc_gp_saw_ss = 0;
3761 	rack->rc_dragged_bottom = 0;
3762 skip_measurement:
3763 
3764 #ifdef STATS
3765 	stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_GPUT,
3766 				 gput);
3767 	/*
3768 	 * XXXLAS: This is a temporary hack, and should be
3769 	 * chained off VOI_TCP_GPUT when stats(9) grows an
3770 	 * API to deal with chained VOIs.
3771 	 */
3772 	if (tp->t_stats_gput_prev > 0)
3773 		stats_voi_update_abs_s32(tp->t_stats,
3774 					 VOI_TCP_GPUT_ND,
3775 					 ((gput - tp->t_stats_gput_prev) * 100) /
3776 					 tp->t_stats_gput_prev);
3777 #endif
3778 	tp->t_flags &= ~TF_GPUTINPROG;
3779 	tp->t_stats_gput_prev = gput;
3780 	/*
3781 	 * Now are we app limited now and there is space from where we
3782 	 * were to where we want to go?
3783 	 *
3784 	 * We don't do the other case i.e. non-applimited here since
3785 	 * the next send will trigger us picking up the missing data.
3786 	 */
3787 	if (rack->r_ctl.rc_first_appl &&
3788 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
3789 	    rack->r_ctl.rc_app_limited_cnt &&
3790 	    (SEQ_GT(rack->r_ctl.rc_first_appl->r_start, th_ack)) &&
3791 	    ((rack->r_ctl.rc_first_appl->r_start - th_ack) >
3792 	     max(rc_init_window(rack), (MIN_GP_WIN * segsiz)))) {
3793 		/*
3794 		 * Yep there is enough outstanding to make a measurement here.
3795 		 */
3796 		struct rack_sendmap *rsm, fe;
3797 
3798 		tp->t_flags |= TF_GPUTINPROG;
3799 		rack->r_ctl.rc_gp_lowrtt = 0xffffffff;
3800 		rack->r_ctl.rc_gp_high_rwnd = rack->rc_tp->snd_wnd;
3801 		tp->gput_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
3802 		rack->app_limited_needs_set = 0;
3803 		tp->gput_seq = th_ack;
3804 		if (rack->in_probe_rtt)
3805 			rack->measure_saw_probe_rtt = 1;
3806 		else if ((rack->measure_saw_probe_rtt) &&
3807 			 (SEQ_GEQ(tp->gput_seq, rack->r_ctl.rc_probertt_sndmax_atexit)))
3808 			rack->measure_saw_probe_rtt = 0;
3809 		if ((rack->r_ctl.rc_first_appl->r_start - th_ack) >= rack_get_measure_window(tp, rack)) {
3810 			/* There is a full window to gain info from */
3811 			tp->gput_ack = tp->gput_seq + rack_get_measure_window(tp, rack);
3812 		} else {
3813 			/* We can only measure up to the applimited point */
3814 			tp->gput_ack = tp->gput_seq + (rack->r_ctl.rc_first_appl->r_start - th_ack);
3815 		}
3816 		/*
3817 		 * Now we need to find the timestamp of the send at tp->gput_seq
3818 		 * for the send based measurement.
3819 		 */
3820 		fe.r_start = tp->gput_seq;
3821 		rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
3822 		if (rsm) {
3823 			/* Ok send-based limit is set */
3824 			if (SEQ_LT(rsm->r_start, tp->gput_seq)) {
3825 				/*
3826 				 * Move back to include the earlier part
3827 				 * so our ack time lines up right (this may
3828 				 * make an overlapping measurement but thats
3829 				 * ok).
3830 				 */
3831 				tp->gput_seq = rsm->r_start;
3832 			}
3833 			if (rsm->r_flags & RACK_ACKED)
3834 				tp->gput_ts = rsm->r_ack_arrival;
3835 			else
3836 				rack->app_limited_needs_set = 1;
3837 			rack->r_ctl.rc_gp_output_ts = rsm->usec_orig_send;
3838 		} else {
3839 			/*
3840 			 * If we don't find the rsm due to some
3841 			 * send-limit set the current time, which
3842 			 * basically disables the send-limit.
3843 			 */
3844 			rack->r_ctl.rc_gp_output_ts = tcp_get_usecs(NULL);
3845 		}
3846 		rack_log_pacing_delay_calc(rack,
3847 					   tp->gput_seq,
3848 					   tp->gput_ack,
3849 					   (uint64_t)rsm,
3850 					   tp->gput_ts,
3851 					   rack->r_ctl.rc_app_limited_cnt,
3852 					   9,
3853 					   __LINE__, NULL);
3854 	}
3855 }
3856 
3857 /*
3858  * CC wrapper hook functions
3859  */
3860 static void
3861 rack_ack_received(struct tcpcb *tp, struct tcp_rack *rack, struct tcphdr *th, uint16_t nsegs,
3862     uint16_t type, int32_t recovery)
3863 {
3864 	INP_WLOCK_ASSERT(tp->t_inpcb);
3865 	tp->ccv->nsegs = nsegs;
3866 	tp->ccv->bytes_this_ack = BYTES_THIS_ACK(tp, th);
3867 	if ((recovery) && (rack->r_ctl.rc_early_recovery_segs)) {
3868 		uint32_t max;
3869 
3870 		max = rack->r_ctl.rc_early_recovery_segs * ctf_fixed_maxseg(tp);
3871 		if (tp->ccv->bytes_this_ack > max) {
3872 			tp->ccv->bytes_this_ack = max;
3873 		}
3874 	}
3875 	if (rack->r_ctl.cwnd_to_use <= tp->snd_wnd)
3876 		tp->ccv->flags |= CCF_CWND_LIMITED;
3877 	else
3878 		tp->ccv->flags &= ~CCF_CWND_LIMITED;
3879 #ifdef STATS
3880 	stats_voi_update_abs_s32(tp->t_stats, VOI_TCP_CALCFRWINDIFF,
3881 	    ((int32_t)rack->r_ctl.cwnd_to_use) - tp->snd_wnd);
3882 #endif
3883 	if ((tp->t_flags & TF_GPUTINPROG) &&
3884 	    rack_enough_for_measurement(tp, rack, th->th_ack)) {
3885 		/* Measure the Goodput */
3886 		rack_do_goodput_measurement(tp, rack, th->th_ack, __LINE__);
3887 #ifdef NETFLIX_PEAKRATE
3888 		if ((type == CC_ACK) &&
3889 		    (tp->t_maxpeakrate)) {
3890 			/*
3891 			 * We update t_peakrate_thr. This gives us roughly
3892 			 * one update per round trip time. Note
3893 			 * it will only be used if pace_always is off i.e
3894 			 * we don't do this for paced flows.
3895 			 */
3896 			tcp_update_peakrate_thr(tp);
3897 		}
3898 #endif
3899 	}
3900 	if (rack->r_ctl.cwnd_to_use > tp->snd_ssthresh) {
3901 		tp->t_bytes_acked += tp->ccv->bytes_this_ack;
3902 		if (tp->t_bytes_acked >= rack->r_ctl.cwnd_to_use) {
3903 			tp->t_bytes_acked -= rack->r_ctl.cwnd_to_use;
3904 			tp->ccv->flags |= CCF_ABC_SENTAWND;
3905 		}
3906 	} else {
3907 		tp->ccv->flags &= ~CCF_ABC_SENTAWND;
3908 		tp->t_bytes_acked = 0;
3909 	}
3910 	if (CC_ALGO(tp)->ack_received != NULL) {
3911 		/* XXXLAS: Find a way to live without this */
3912 		tp->ccv->curack = th->th_ack;
3913 		CC_ALGO(tp)->ack_received(tp->ccv, type);
3914 	}
3915 #ifdef STATS
3916 	stats_voi_update_abs_ulong(tp->t_stats, VOI_TCP_LCWIN, rack->r_ctl.cwnd_to_use);
3917 #endif
3918 	if (rack->r_ctl.rc_rack_largest_cwnd < rack->r_ctl.cwnd_to_use) {
3919 		rack->r_ctl.rc_rack_largest_cwnd = rack->r_ctl.cwnd_to_use;
3920 	}
3921 #ifdef NETFLIX_PEAKRATE
3922 	/* we enforce max peak rate if it is set and we are not pacing */
3923 	if ((rack->rc_always_pace == 0) &&
3924 	    tp->t_peakrate_thr &&
3925 	    (tp->snd_cwnd > tp->t_peakrate_thr)) {
3926 		tp->snd_cwnd = tp->t_peakrate_thr;
3927 	}
3928 #endif
3929 }
3930 
3931 static void
3932 tcp_rack_partialack(struct tcpcb *tp, struct tcphdr *th)
3933 {
3934 	struct tcp_rack *rack;
3935 
3936 	rack = (struct tcp_rack *)tp->t_fb_ptr;
3937 	INP_WLOCK_ASSERT(tp->t_inpcb);
3938 	/*
3939 	 * If we are doing PRR and have enough
3940 	 * room to send <or> we are pacing and prr
3941 	 * is disabled we will want to see if we
3942 	 * can send data (by setting r_wanted_output to
3943 	 * true).
3944 	 */
3945 	if ((rack->r_ctl.rc_prr_sndcnt > 0) ||
3946 	    rack->rack_no_prr)
3947 		rack->r_wanted_output = 1;
3948 }
3949 
3950 static void
3951 rack_post_recovery(struct tcpcb *tp, struct tcphdr *th)
3952 {
3953 	struct tcp_rack *rack;
3954 	uint32_t orig_cwnd;
3955 
3956 	orig_cwnd = tp->snd_cwnd;
3957 	INP_WLOCK_ASSERT(tp->t_inpcb);
3958 	rack = (struct tcp_rack *)tp->t_fb_ptr;
3959 	if (rack->rc_not_backing_off == 0) {
3960 		/* only alert CC if we alerted when we entered */
3961 		if (CC_ALGO(tp)->post_recovery != NULL) {
3962 			tp->ccv->curack = th->th_ack;
3963 			CC_ALGO(tp)->post_recovery(tp->ccv);
3964 		}
3965 		if (tp->snd_cwnd > tp->snd_ssthresh) {
3966 			/* Drop us down to the ssthresh (1/2 cwnd at loss) */
3967 			tp->snd_cwnd = tp->snd_ssthresh;
3968 		}
3969 	}
3970 	if ((rack->rack_no_prr == 0) &&
3971 	    (rack->r_ctl.rc_prr_sndcnt > 0)) {
3972 		/* Suck the next prr cnt back into cwnd */
3973 		tp->snd_cwnd += rack->r_ctl.rc_prr_sndcnt;
3974 		rack->r_ctl.rc_prr_sndcnt = 0;
3975 		rack_log_to_prr(rack, 1, 0);
3976 	}
3977 	rack_log_to_prr(rack, 14, orig_cwnd);
3978 	tp->snd_recover = tp->snd_una;
3979 	EXIT_RECOVERY(tp->t_flags);
3980 }
3981 
3982 static void
3983 rack_cong_signal(struct tcpcb *tp, struct tcphdr *th, uint32_t type)
3984 {
3985 	struct tcp_rack *rack;
3986 
3987 	INP_WLOCK_ASSERT(tp->t_inpcb);
3988 
3989 	rack = (struct tcp_rack *)tp->t_fb_ptr;
3990 	switch (type) {
3991 	case CC_NDUPACK:
3992 		tp->t_flags &= ~TF_WASFRECOVERY;
3993 		tp->t_flags &= ~TF_WASCRECOVERY;
3994 		if (!IN_FASTRECOVERY(tp->t_flags)) {
3995 			rack->r_ctl.rc_prr_delivered = 0;
3996 			rack->r_ctl.rc_prr_out = 0;
3997 			if (rack->rack_no_prr == 0) {
3998 				rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
3999 				rack_log_to_prr(rack, 2, 0);
4000 			}
4001 			rack->r_ctl.rc_prr_recovery_fs = tp->snd_max - tp->snd_una;
4002 			tp->snd_recover = tp->snd_max;
4003 			if (tp->t_flags2 & TF2_ECN_PERMIT)
4004 				tp->t_flags2 |= TF2_ECN_SND_CWR;
4005 		}
4006 		break;
4007 	case CC_ECN:
4008 		if (!IN_CONGRECOVERY(tp->t_flags) ||
4009 		    /*
4010 		     * Allow ECN reaction on ACK to CWR, if
4011 		     * that data segment was also CE marked.
4012 		     */
4013 		    SEQ_GEQ(th->th_ack, tp->snd_recover)) {
4014 			EXIT_CONGRECOVERY(tp->t_flags);
4015 			KMOD_TCPSTAT_INC(tcps_ecn_rcwnd);
4016 			tp->snd_recover = tp->snd_max + 1;
4017 			if (tp->t_flags2 & TF2_ECN_PERMIT)
4018 				tp->t_flags2 |= TF2_ECN_SND_CWR;
4019 		}
4020 		break;
4021 	case CC_RTO:
4022 		tp->t_dupacks = 0;
4023 		tp->t_bytes_acked = 0;
4024 		EXIT_RECOVERY(tp->t_flags);
4025 		tp->snd_ssthresh = max(2, min(tp->snd_wnd, rack->r_ctl.cwnd_to_use) / 2 /
4026 		    ctf_fixed_maxseg(tp)) * ctf_fixed_maxseg(tp);
4027 		tp->snd_cwnd = ctf_fixed_maxseg(tp);
4028 		if (tp->t_flags2 & TF2_ECN_PERMIT)
4029 			tp->t_flags2 |= TF2_ECN_SND_CWR;
4030 		break;
4031 	case CC_RTO_ERR:
4032 		KMOD_TCPSTAT_INC(tcps_sndrexmitbad);
4033 		/* RTO was unnecessary, so reset everything. */
4034 		tp->snd_cwnd = tp->snd_cwnd_prev;
4035 		tp->snd_ssthresh = tp->snd_ssthresh_prev;
4036 		tp->snd_recover = tp->snd_recover_prev;
4037 		if (tp->t_flags & TF_WASFRECOVERY) {
4038 			ENTER_FASTRECOVERY(tp->t_flags);
4039 			tp->t_flags &= ~TF_WASFRECOVERY;
4040 		}
4041 		if (tp->t_flags & TF_WASCRECOVERY) {
4042 			ENTER_CONGRECOVERY(tp->t_flags);
4043 			tp->t_flags &= ~TF_WASCRECOVERY;
4044 		}
4045 		tp->snd_nxt = tp->snd_max;
4046 		tp->t_badrxtwin = 0;
4047 		break;
4048 	}
4049 	/*
4050 	 * If we are below our max rtt, don't
4051 	 * signal the CC control to change things.
4052 	 * instead set it up so that we are in
4053 	 * recovery but not going to back off.
4054 	 */
4055 
4056 	if (rack->rc_highly_buffered) {
4057 		/*
4058 		 * Do we use the higher rtt for
4059 		 * our threshold to not backoff (like CDG)?
4060 		 */
4061 		uint32_t rtt_mul, rtt_div;
4062 
4063 		if (rack_use_max_for_nobackoff) {
4064 			rtt_mul = (rack_gp_rtt_maxmul - 1);
4065 			rtt_div = 1;
4066 		} else {
4067 			rtt_mul = rack_gp_rtt_minmul;
4068 			rtt_div = max(rack_gp_rtt_mindiv , 1);
4069 		}
4070 		if (rack->r_ctl.rc_gp_srtt <= (rack->r_ctl.rc_lowest_us_rtt +
4071 					       ((rack->r_ctl.rc_lowest_us_rtt * rtt_mul) /
4072 						rtt_div))) {
4073 			/* below our min threshold */
4074 			rack->rc_not_backing_off = 1;
4075 			ENTER_RECOVERY(rack->rc_tp->t_flags);
4076 			rack_log_rtt_shrinks(rack, 0,
4077 					     rtt_mul,
4078 					     rtt_div,
4079 					     RACK_RTTS_NOBACKOFF);
4080 			return;
4081 		}
4082 	}
4083 	rack->rc_not_backing_off = 0;
4084 	if (CC_ALGO(tp)->cong_signal != NULL) {
4085 		if (th != NULL)
4086 			tp->ccv->curack = th->th_ack;
4087 		CC_ALGO(tp)->cong_signal(tp->ccv, type);
4088 	}
4089 }
4090 
4091 static inline void
4092 rack_cc_after_idle(struct tcp_rack *rack, struct tcpcb *tp)
4093 {
4094 	uint32_t i_cwnd;
4095 
4096 	INP_WLOCK_ASSERT(tp->t_inpcb);
4097 
4098 #ifdef NETFLIX_STATS
4099 	KMOD_TCPSTAT_INC(tcps_idle_restarts);
4100 	if (tp->t_state == TCPS_ESTABLISHED)
4101 		KMOD_TCPSTAT_INC(tcps_idle_estrestarts);
4102 #endif
4103 	if (CC_ALGO(tp)->after_idle != NULL)
4104 		CC_ALGO(tp)->after_idle(tp->ccv);
4105 
4106 	if (tp->snd_cwnd == 1)
4107 		i_cwnd = tp->t_maxseg;		/* SYN(-ACK) lost */
4108 	else
4109 		i_cwnd = rc_init_window(rack);
4110 
4111 	/*
4112 	 * Being idle is no differnt than the initial window. If the cc
4113 	 * clamps it down below the initial window raise it to the initial
4114 	 * window.
4115 	 */
4116 	if (tp->snd_cwnd < i_cwnd) {
4117 		tp->snd_cwnd = i_cwnd;
4118 	}
4119 }
4120 
4121 /*
4122  * Indicate whether this ack should be delayed.  We can delay the ack if
4123  * following conditions are met:
4124  *	- There is no delayed ack timer in progress.
4125  *	- Our last ack wasn't a 0-sized window. We never want to delay
4126  *	  the ack that opens up a 0-sized window.
4127  *	- LRO wasn't used for this segment. We make sure by checking that the
4128  *	  segment size is not larger than the MSS.
4129  *	- Delayed acks are enabled or this is a half-synchronized T/TCP
4130  *	  connection.
4131  */
4132 #define DELAY_ACK(tp, tlen)			 \
4133 	(((tp->t_flags & TF_RXWIN0SENT) == 0) && \
4134 	((tp->t_flags & TF_DELACK) == 0) && 	 \
4135 	(tlen <= tp->t_maxseg) &&		 \
4136 	(tp->t_delayed_ack || (tp->t_flags & TF_NEEDSYN)))
4137 
4138 static struct rack_sendmap *
4139 rack_find_lowest_rsm(struct tcp_rack *rack)
4140 {
4141 	struct rack_sendmap *rsm;
4142 
4143 	/*
4144 	 * Walk the time-order transmitted list looking for an rsm that is
4145 	 * not acked. This will be the one that was sent the longest time
4146 	 * ago that is still outstanding.
4147 	 */
4148 	TAILQ_FOREACH(rsm, &rack->r_ctl.rc_tmap, r_tnext) {
4149 		if (rsm->r_flags & RACK_ACKED) {
4150 			continue;
4151 		}
4152 		goto finish;
4153 	}
4154 finish:
4155 	return (rsm);
4156 }
4157 
4158 static struct rack_sendmap *
4159 rack_find_high_nonack(struct tcp_rack *rack, struct rack_sendmap *rsm)
4160 {
4161 	struct rack_sendmap *prsm;
4162 
4163 	/*
4164 	 * Walk the sequence order list backward until we hit and arrive at
4165 	 * the highest seq not acked. In theory when this is called it
4166 	 * should be the last segment (which it was not).
4167 	 */
4168 	counter_u64_add(rack_find_high, 1);
4169 	prsm = rsm;
4170 	RB_FOREACH_REVERSE_FROM(prsm, rack_rb_tree_head, rsm) {
4171 		if (prsm->r_flags & (RACK_ACKED | RACK_HAS_FIN)) {
4172 			continue;
4173 		}
4174 		return (prsm);
4175 	}
4176 	return (NULL);
4177 }
4178 
4179 static uint32_t
4180 rack_calc_thresh_rack(struct tcp_rack *rack, uint32_t srtt, uint32_t cts)
4181 {
4182 	int32_t lro;
4183 	uint32_t thresh;
4184 
4185 	/*
4186 	 * lro is the flag we use to determine if we have seen reordering.
4187 	 * If it gets set we have seen reordering. The reorder logic either
4188 	 * works in one of two ways:
4189 	 *
4190 	 * If reorder-fade is configured, then we track the last time we saw
4191 	 * re-ordering occur. If we reach the point where enough time as
4192 	 * passed we no longer consider reordering has occuring.
4193 	 *
4194 	 * Or if reorder-face is 0, then once we see reordering we consider
4195 	 * the connection to alway be subject to reordering and just set lro
4196 	 * to 1.
4197 	 *
4198 	 * In the end if lro is non-zero we add the extra time for
4199 	 * reordering in.
4200 	 */
4201 	if (srtt == 0)
4202 		srtt = 1;
4203 	if (rack->r_ctl.rc_reorder_ts) {
4204 		if (rack->r_ctl.rc_reorder_fade) {
4205 			if (SEQ_GEQ(cts, rack->r_ctl.rc_reorder_ts)) {
4206 				lro = cts - rack->r_ctl.rc_reorder_ts;
4207 				if (lro == 0) {
4208 					/*
4209 					 * No time as passed since the last
4210 					 * reorder, mark it as reordering.
4211 					 */
4212 					lro = 1;
4213 				}
4214 			} else {
4215 				/* Negative time? */
4216 				lro = 0;
4217 			}
4218 			if (lro > rack->r_ctl.rc_reorder_fade) {
4219 				/* Turn off reordering seen too */
4220 				rack->r_ctl.rc_reorder_ts = 0;
4221 				lro = 0;
4222 			}
4223 		} else {
4224 			/* Reodering does not fade */
4225 			lro = 1;
4226 		}
4227 	} else {
4228 		lro = 0;
4229 	}
4230 	thresh = srtt + rack->r_ctl.rc_pkt_delay;
4231 	if (lro) {
4232 		/* It must be set, if not you get 1/4 rtt */
4233 		if (rack->r_ctl.rc_reorder_shift)
4234 			thresh += (srtt >> rack->r_ctl.rc_reorder_shift);
4235 		else
4236 			thresh += (srtt >> 2);
4237 	} else {
4238 		thresh += 1;
4239 	}
4240 	/* We don't let the rack timeout be above a RTO */
4241 	if (thresh > TICKS_2_MSEC(rack->rc_tp->t_rxtcur)) {
4242 		thresh = TICKS_2_MSEC(rack->rc_tp->t_rxtcur);
4243 	}
4244 	/* And we don't want it above the RTO max either */
4245 	if (thresh > rack_rto_max) {
4246 		thresh = rack_rto_max;
4247 	}
4248 	return (thresh);
4249 }
4250 
4251 static uint32_t
4252 rack_calc_thresh_tlp(struct tcpcb *tp, struct tcp_rack *rack,
4253 		     struct rack_sendmap *rsm, uint32_t srtt)
4254 {
4255 	struct rack_sendmap *prsm;
4256 	uint32_t thresh, len;
4257 	int segsiz;
4258 
4259 	if (srtt == 0)
4260 		srtt = 1;
4261 	if (rack->r_ctl.rc_tlp_threshold)
4262 		thresh = srtt + (srtt / rack->r_ctl.rc_tlp_threshold);
4263 	else
4264 		thresh = (srtt * 2);
4265 
4266 	/* Get the previous sent packet, if any  */
4267 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
4268 	counter_u64_add(rack_enter_tlp_calc, 1);
4269 	len = rsm->r_end - rsm->r_start;
4270 	if (rack->rack_tlp_threshold_use == TLP_USE_ID) {
4271 		/* Exactly like the ID */
4272 		if (((tp->snd_max - tp->snd_una) - rack->r_ctl.rc_sacked + rack->r_ctl.rc_holes_rxt) <= segsiz) {
4273 			uint32_t alt_thresh;
4274 			/*
4275 			 * Compensate for delayed-ack with the d-ack time.
4276 			 */
4277 			counter_u64_add(rack_used_tlpmethod, 1);
4278 			alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time;
4279 			if (alt_thresh > thresh)
4280 				thresh = alt_thresh;
4281 		}
4282 	} else if (rack->rack_tlp_threshold_use == TLP_USE_TWO_ONE) {
4283 		/* 2.1 behavior */
4284 		prsm = TAILQ_PREV(rsm, rack_head, r_tnext);
4285 		if (prsm && (len <= segsiz)) {
4286 			/*
4287 			 * Two packets outstanding, thresh should be (2*srtt) +
4288 			 * possible inter-packet delay (if any).
4289 			 */
4290 			uint32_t inter_gap = 0;
4291 			int idx, nidx;
4292 
4293 			counter_u64_add(rack_used_tlpmethod, 1);
4294 			idx = rsm->r_rtr_cnt - 1;
4295 			nidx = prsm->r_rtr_cnt - 1;
4296 			if (TSTMP_GEQ(rsm->r_tim_lastsent[nidx], prsm->r_tim_lastsent[idx])) {
4297 				/* Yes it was sent later (or at the same time) */
4298 				inter_gap = rsm->r_tim_lastsent[idx] - prsm->r_tim_lastsent[nidx];
4299 			}
4300 			thresh += inter_gap;
4301 		} else 	if (len <= segsiz) {
4302 			/*
4303 			 * Possibly compensate for delayed-ack.
4304 			 */
4305 			uint32_t alt_thresh;
4306 
4307 			counter_u64_add(rack_used_tlpmethod2, 1);
4308 			alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time;
4309 			if (alt_thresh > thresh)
4310 				thresh = alt_thresh;
4311 		}
4312 	} else if (rack->rack_tlp_threshold_use == TLP_USE_TWO_TWO) {
4313 		/* 2.2 behavior */
4314 		if (len <= segsiz) {
4315 			uint32_t alt_thresh;
4316 			/*
4317 			 * Compensate for delayed-ack with the d-ack time.
4318 			 */
4319 			counter_u64_add(rack_used_tlpmethod, 1);
4320 			alt_thresh = srtt + (srtt / 2) + rack_delayed_ack_time;
4321 			if (alt_thresh > thresh)
4322 				thresh = alt_thresh;
4323 		}
4324 	}
4325  	/* Not above an RTO */
4326 	if (thresh > TICKS_2_MSEC(tp->t_rxtcur)) {
4327 		thresh = TICKS_2_MSEC(tp->t_rxtcur);
4328 	}
4329 	/* Not above a RTO max */
4330 	if (thresh > rack_rto_max) {
4331 		thresh = rack_rto_max;
4332 	}
4333 	/* Apply user supplied min TLP */
4334 	if (thresh < rack_tlp_min) {
4335 		thresh = rack_tlp_min;
4336 	}
4337 	return (thresh);
4338 }
4339 
4340 static uint32_t
4341 rack_grab_rtt(struct tcpcb *tp, struct tcp_rack *rack)
4342 {
4343 	/*
4344 	 * We want the rack_rtt which is the
4345 	 * last rtt we measured. However if that
4346 	 * does not exist we fallback to the srtt (which
4347 	 * we probably will never do) and then as a last
4348 	 * resort we use RACK_INITIAL_RTO if no srtt is
4349 	 * yet set.
4350 	 */
4351 	if (rack->rc_rack_rtt)
4352 		return(rack->rc_rack_rtt);
4353 	else if (tp->t_srtt == 0)
4354 		return(RACK_INITIAL_RTO);
4355 	return (TICKS_2_MSEC(tp->t_srtt >> TCP_RTT_SHIFT));
4356 }
4357 
4358 static struct rack_sendmap *
4359 rack_check_recovery_mode(struct tcpcb *tp, uint32_t tsused)
4360 {
4361 	/*
4362 	 * Check to see that we don't need to fall into recovery. We will
4363 	 * need to do so if our oldest transmit is past the time we should
4364 	 * have had an ack.
4365 	 */
4366 	struct tcp_rack *rack;
4367 	struct rack_sendmap *rsm;
4368 	int32_t idx;
4369 	uint32_t srtt, thresh;
4370 
4371 	rack = (struct tcp_rack *)tp->t_fb_ptr;
4372 	if (RB_EMPTY(&rack->r_ctl.rc_mtree)) {
4373 		return (NULL);
4374 	}
4375 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
4376 	if (rsm == NULL)
4377 		return (NULL);
4378 
4379 	if (rsm->r_flags & RACK_ACKED) {
4380 		rsm = rack_find_lowest_rsm(rack);
4381 		if (rsm == NULL)
4382 			return (NULL);
4383 	}
4384 	idx = rsm->r_rtr_cnt - 1;
4385 	srtt = rack_grab_rtt(tp, rack);
4386 	thresh = rack_calc_thresh_rack(rack, srtt, tsused);
4387 	if (TSTMP_LT(tsused, rsm->r_tim_lastsent[idx])) {
4388 		return (NULL);
4389 	}
4390 	if ((tsused - rsm->r_tim_lastsent[idx]) < thresh) {
4391 		return (NULL);
4392 	}
4393 	/* Ok if we reach here we are over-due and this guy can be sent */
4394 	if (IN_RECOVERY(tp->t_flags) == 0) {
4395 		/*
4396 		 * For the one that enters us into recovery record undo
4397 		 * info.
4398 		 */
4399 		rack->r_ctl.rc_rsm_start = rsm->r_start;
4400 		rack->r_ctl.rc_cwnd_at = tp->snd_cwnd;
4401 		rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh;
4402 	}
4403 	rack_cong_signal(tp, NULL, CC_NDUPACK);
4404 	return (rsm);
4405 }
4406 
4407 static uint32_t
4408 rack_get_persists_timer_val(struct tcpcb *tp, struct tcp_rack *rack)
4409 {
4410 	int32_t t;
4411 	int32_t tt;
4412 	uint32_t ret_val;
4413 
4414 	t = TICKS_2_MSEC((tp->t_srtt >> TCP_RTT_SHIFT) + ((tp->t_rttvar * 4) >> TCP_RTT_SHIFT));
4415 	TCPT_RANGESET(tt, t * tcp_backoff[tp->t_rxtshift],
4416 	    rack_persist_min, rack_persist_max);
4417 	if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
4418 		tp->t_rxtshift++;
4419 	rack->r_ctl.rc_hpts_flags |= PACE_TMR_PERSIT;
4420 	ret_val = (uint32_t)tt;
4421 	return (ret_val);
4422 }
4423 
4424 static uint32_t
4425 rack_timer_start(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int sup_rack)
4426 {
4427 	/*
4428 	 * Start the FR timer, we do this based on getting the first one in
4429 	 * the rc_tmap. Note that if its NULL we must stop the timer. in all
4430 	 * events we need to stop the running timer (if its running) before
4431 	 * starting the new one.
4432 	 */
4433 	uint32_t thresh, exp, to, srtt, time_since_sent, tstmp_touse;
4434 	uint32_t srtt_cur;
4435 	int32_t idx;
4436 	int32_t is_tlp_timer = 0;
4437 	struct rack_sendmap *rsm;
4438 
4439 	if (rack->t_timers_stopped) {
4440 		/* All timers have been stopped none are to run */
4441 		return (0);
4442 	}
4443 	if (rack->rc_in_persist) {
4444 		/* We can't start any timer in persists */
4445 		return (rack_get_persists_timer_val(tp, rack));
4446 	}
4447 	rack->rc_on_min_to = 0;
4448 	if ((tp->t_state < TCPS_ESTABLISHED) ||
4449 	    ((tp->t_flags & TF_SACK_PERMIT) == 0))
4450 		goto activate_rxt;
4451 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
4452 	if ((rsm == NULL) || sup_rack) {
4453 		/* Nothing on the send map */
4454 activate_rxt:
4455 		time_since_sent = 0;
4456 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
4457 		if (rsm) {
4458 			idx = rsm->r_rtr_cnt - 1;
4459 			if (TSTMP_GEQ(rsm->r_tim_lastsent[idx], rack->r_ctl.rc_tlp_rxt_last_time))
4460 				tstmp_touse = rsm->r_tim_lastsent[idx];
4461 			else
4462 				tstmp_touse = rack->r_ctl.rc_tlp_rxt_last_time;
4463 			if (TSTMP_GT(cts, tstmp_touse))
4464 			    time_since_sent = cts - tstmp_touse;
4465 		}
4466 		if (SEQ_LT(tp->snd_una, tp->snd_max) || sbavail(&(tp->t_inpcb->inp_socket->so_snd))) {
4467 			rack->r_ctl.rc_hpts_flags |= PACE_TMR_RXT;
4468 			to = TICKS_2_MSEC(tp->t_rxtcur);
4469 			if (to > time_since_sent)
4470 				to -= time_since_sent;
4471 			else
4472 				to = rack->r_ctl.rc_min_to;
4473 			if (to == 0)
4474 				to = 1;
4475 			return (to);
4476 		}
4477 		return (0);
4478 	}
4479 	if (rsm->r_flags & RACK_ACKED) {
4480 		rsm = rack_find_lowest_rsm(rack);
4481 		if (rsm == NULL) {
4482 			/* No lowest? */
4483 			goto activate_rxt;
4484 		}
4485 	}
4486 	if (rack->sack_attack_disable) {
4487 		/*
4488 		 * We don't want to do
4489 		 * any TLP's if you are an attacker.
4490 		 * Though if you are doing what
4491 		 * is expected you may still have
4492 		 * SACK-PASSED marks.
4493 		 */
4494 		goto activate_rxt;
4495 	}
4496 	/* Convert from ms to usecs */
4497 	if ((rsm->r_flags & RACK_SACK_PASSED) || (rsm->r_dupack >= DUP_ACK_THRESHOLD)) {
4498 		if ((tp->t_flags & TF_SENTFIN) &&
4499 		    ((tp->snd_max - tp->snd_una) == 1) &&
4500 		    (rsm->r_flags & RACK_HAS_FIN)) {
4501 			/*
4502 			 * We don't start a rack timer if all we have is a
4503 			 * FIN outstanding.
4504 			 */
4505 			goto activate_rxt;
4506 		}
4507 		if ((rack->use_rack_rr == 0) &&
4508 		    (IN_RECOVERY(tp->t_flags)) &&
4509 		    (rack->rack_no_prr == 0) &&
4510 		     (rack->r_ctl.rc_prr_sndcnt  < ctf_fixed_maxseg(tp))) {
4511 			/*
4512 			 * We are not cheating, in recovery  and
4513 			 * not enough ack's to yet get our next
4514 			 * retransmission out.
4515 			 *
4516 			 * Note that classified attackers do not
4517 			 * get to use the rack-cheat.
4518 			 */
4519 			goto activate_tlp;
4520 		}
4521 		srtt = rack_grab_rtt(tp, rack);
4522 		thresh = rack_calc_thresh_rack(rack, srtt, cts);
4523 		idx = rsm->r_rtr_cnt - 1;
4524 		exp = rsm->r_tim_lastsent[idx] + thresh;
4525 		if (SEQ_GEQ(exp, cts)) {
4526 			to = exp - cts;
4527 			if (to < rack->r_ctl.rc_min_to) {
4528 				to = rack->r_ctl.rc_min_to;
4529 				if (rack->r_rr_config == 3)
4530 					rack->rc_on_min_to = 1;
4531 			}
4532 		} else {
4533 			to = rack->r_ctl.rc_min_to;
4534 			if (rack->r_rr_config == 3)
4535 				rack->rc_on_min_to = 1;
4536 		}
4537 	} else {
4538 		/* Ok we need to do a TLP not RACK */
4539 activate_tlp:
4540 		if ((rack->rc_tlp_in_progress != 0) &&
4541 		    (rack->r_ctl.rc_tlp_cnt_out >= rack_tlp_limit)) {
4542 			/*
4543 			 * The previous send was a TLP and we have sent
4544 			 * N TLP's without sending new data.
4545 			 */
4546 			goto activate_rxt;
4547 		}
4548 		rsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_tmap, rack_sendmap, r_tnext);
4549 		if (rsm == NULL) {
4550 			/* We found no rsm to TLP with. */
4551 			goto activate_rxt;
4552 		}
4553 		if (rsm->r_flags & RACK_HAS_FIN) {
4554 			/* If its a FIN we dont do TLP */
4555 			rsm = NULL;
4556 			goto activate_rxt;
4557 		}
4558 		idx = rsm->r_rtr_cnt - 1;
4559 		time_since_sent = 0;
4560 		if (TSTMP_GEQ(rsm->r_tim_lastsent[idx], rack->r_ctl.rc_tlp_rxt_last_time))
4561 			tstmp_touse = rsm->r_tim_lastsent[idx];
4562 		else
4563 			tstmp_touse = rack->r_ctl.rc_tlp_rxt_last_time;
4564 		if (TSTMP_GT(cts, tstmp_touse))
4565 		    time_since_sent = cts - tstmp_touse;
4566 		is_tlp_timer = 1;
4567 		if (tp->t_srtt) {
4568 			srtt_cur = (tp->t_srtt >> TCP_RTT_SHIFT);
4569 			srtt = TICKS_2_MSEC(srtt_cur);
4570 		} else
4571 			srtt = RACK_INITIAL_RTO;
4572 		/*
4573 		 * If the SRTT is not keeping up and the
4574 		 * rack RTT has spiked we want to use
4575 		 * the last RTT not the smoothed one.
4576 		 */
4577 		if (rack_tlp_use_greater && (srtt < rack_grab_rtt(tp, rack)))
4578 			srtt = rack_grab_rtt(tp, rack);
4579 		thresh = rack_calc_thresh_tlp(tp, rack, rsm, srtt);
4580 		if (thresh > time_since_sent)
4581 			to = thresh - time_since_sent;
4582 		else {
4583 			to = rack->r_ctl.rc_min_to;
4584 			rack_log_alt_to_to_cancel(rack,
4585 						  thresh,		/* flex1 */
4586 						  time_since_sent,	/* flex2 */
4587 						  tstmp_touse,		/* flex3 */
4588 						  rack->r_ctl.rc_tlp_rxt_last_time, /* flex4 */
4589 						  rsm->r_tim_lastsent[idx],
4590 						  srtt,
4591 						  idx, 99);
4592 		}
4593 		if (to > TCPTV_REXMTMAX) {
4594 			/*
4595 			 * If the TLP time works out to larger than the max
4596 			 * RTO lets not do TLP.. just RTO.
4597 			 */
4598 			goto activate_rxt;
4599 		}
4600 	}
4601 	if (is_tlp_timer == 0) {
4602 		rack->r_ctl.rc_hpts_flags |= PACE_TMR_RACK;
4603 	} else {
4604 		rack->r_ctl.rc_hpts_flags |= PACE_TMR_TLP;
4605 	}
4606 	if (to == 0)
4607 		to = 1;
4608 	return (to);
4609 }
4610 
4611 static void
4612 rack_enter_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
4613 {
4614 	if (rack->rc_in_persist == 0) {
4615 		if (tp->t_flags & TF_GPUTINPROG) {
4616 			/*
4617 			 * Stop the goodput now, the calling of the
4618 			 * measurement function clears the flag.
4619 			 */
4620 			rack_do_goodput_measurement(tp, rack, tp->snd_una, __LINE__);
4621 		}
4622 #ifdef NETFLIX_SHARED_CWND
4623 		if (rack->r_ctl.rc_scw) {
4624 			tcp_shared_cwnd_idle(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
4625 			rack->rack_scwnd_is_idle = 1;
4626 		}
4627 #endif
4628 		rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
4629 		if (rack->r_ctl.rc_went_idle_time == 0)
4630 			rack->r_ctl.rc_went_idle_time = 1;
4631 		rack_timer_cancel(tp, rack, cts, __LINE__);
4632 		tp->t_rxtshift = 0;
4633 		rack->rc_in_persist = 1;
4634 	}
4635 }
4636 
4637 static void
4638 rack_exit_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
4639 {
4640 	if (rack->rc_inp->inp_in_hpts)  {
4641 		tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
4642 		rack->r_ctl.rc_hpts_flags  = 0;
4643 	}
4644 #ifdef NETFLIX_SHARED_CWND
4645 	if (rack->r_ctl.rc_scw) {
4646 		tcp_shared_cwnd_active(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
4647 		rack->rack_scwnd_is_idle = 0;
4648 	}
4649 #endif
4650 	if (rack->rc_gp_dyn_mul &&
4651 	    (rack->use_fixed_rate == 0) &&
4652 	    (rack->rc_always_pace)) {
4653 		/*
4654 		 * Do we count this as if a probe-rtt just
4655 		 * finished?
4656 		 */
4657 		uint32_t time_idle, idle_min;
4658 
4659 		time_idle = tcp_get_usecs(NULL) - rack->r_ctl.rc_went_idle_time;
4660 		idle_min = rack_min_probertt_hold;
4661 		if (rack_probertt_gpsrtt_cnt_div) {
4662 			uint64_t extra;
4663 			extra = (uint64_t)rack->r_ctl.rc_gp_srtt *
4664 				(uint64_t)rack_probertt_gpsrtt_cnt_mul;
4665 			extra /= (uint64_t)rack_probertt_gpsrtt_cnt_div;
4666 			idle_min += (uint32_t)extra;
4667 		}
4668 		if (time_idle >= idle_min)  {
4669 			/* Yes, we count it as a probe-rtt. */
4670 			uint32_t us_cts;
4671 
4672 			us_cts = tcp_get_usecs(NULL);
4673 			if (rack->in_probe_rtt == 0) {
4674 				rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
4675 				rack->r_ctl.rc_time_probertt_entered = rack->r_ctl.rc_lower_rtt_us_cts;
4676 				rack->r_ctl.rc_time_probertt_starts = rack->r_ctl.rc_lower_rtt_us_cts;
4677 				rack->r_ctl.rc_time_of_last_probertt = rack->r_ctl.rc_lower_rtt_us_cts;
4678 			} else {
4679 				rack_exit_probertt(rack, us_cts);
4680 			}
4681 		}
4682 	}
4683 	rack->rc_in_persist = 0;
4684 	rack->r_ctl.rc_went_idle_time = 0;
4685 	tp->t_rxtshift = 0;
4686  	rack->r_ctl.rc_agg_delayed = 0;
4687 	rack->r_early = 0;
4688 	rack->r_late = 0;
4689 	rack->r_ctl.rc_agg_early = 0;
4690 }
4691 
4692 static void
4693 rack_log_hpts_diag(struct tcp_rack *rack, uint32_t cts,
4694 		   struct hpts_diag *diag, struct timeval *tv)
4695 {
4696 	if (rack_verbose_logging && rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
4697 		union tcp_log_stackspecific log;
4698 
4699 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
4700 		log.u_bbr.flex1 = diag->p_nxt_slot;
4701 		log.u_bbr.flex2 = diag->p_cur_slot;
4702 		log.u_bbr.flex3 = diag->slot_req;
4703 		log.u_bbr.flex4 = diag->inp_hptsslot;
4704 		log.u_bbr.flex5 = diag->slot_remaining;
4705 		log.u_bbr.flex6 = diag->need_new_to;
4706 		log.u_bbr.flex7 = diag->p_hpts_active;
4707 		log.u_bbr.flex8 = diag->p_on_min_sleep;
4708 		/* Hijack other fields as needed  */
4709 		log.u_bbr.epoch = diag->have_slept;
4710 		log.u_bbr.lt_epoch = diag->yet_to_sleep;
4711 		log.u_bbr.pkts_out = diag->co_ret;
4712 		log.u_bbr.applimited = diag->hpts_sleep_time;
4713 		log.u_bbr.delivered = diag->p_prev_slot;
4714 		log.u_bbr.inflight = diag->p_runningtick;
4715 		log.u_bbr.bw_inuse = diag->wheel_tick;
4716 		log.u_bbr.rttProp = diag->wheel_cts;
4717 		log.u_bbr.timeStamp = cts;
4718 		log.u_bbr.delRate = diag->maxticks;
4719 		log.u_bbr.cur_del_rate = diag->p_curtick;
4720 		log.u_bbr.cur_del_rate <<= 32;
4721 		log.u_bbr.cur_del_rate |= diag->p_lasttick;
4722 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
4723 		    &rack->rc_inp->inp_socket->so_rcv,
4724 		    &rack->rc_inp->inp_socket->so_snd,
4725 		    BBR_LOG_HPTSDIAG, 0,
4726 		    0, &log, false, tv);
4727 	}
4728 
4729 }
4730 
4731 static void
4732 rack_start_hpts_timer(struct tcp_rack *rack, struct tcpcb *tp, uint32_t cts,
4733       int32_t slot, uint32_t tot_len_this_send, int sup_rack)
4734 {
4735 	struct hpts_diag diag;
4736 	struct inpcb *inp;
4737 	struct timeval tv;
4738 	uint32_t delayed_ack = 0;
4739 	uint32_t hpts_timeout;
4740 	uint8_t stopped;
4741 	uint32_t left = 0;
4742 	uint32_t us_cts;
4743 
4744 	inp = tp->t_inpcb;
4745 	if ((tp->t_state == TCPS_CLOSED) ||
4746 	    (tp->t_state == TCPS_LISTEN)) {
4747 		return;
4748 	}
4749 	if (inp->inp_in_hpts) {
4750 		/* Already on the pacer */
4751 		return;
4752 	}
4753 	stopped = rack->rc_tmr_stopped;
4754 	if (stopped && TSTMP_GT(rack->r_ctl.rc_timer_exp, cts)) {
4755 		left = rack->r_ctl.rc_timer_exp - cts;
4756 	}
4757 	rack->r_ctl.rc_timer_exp = 0;
4758 	rack->r_ctl.rc_hpts_flags = 0;
4759 	us_cts = tcp_get_usecs(&tv);
4760 	/* Now early/late accounting */
4761 	if (rack->r_early) {
4762 		/*
4763 		 * We have a early carry over set,
4764 		 * we can always add more time so we
4765 		 * can always make this compensation.
4766 		 */
4767 		slot += rack->r_ctl.rc_agg_early;
4768 		rack->r_early = 0;
4769 		rack->r_ctl.rc_agg_early = 0;
4770 	}
4771 	if (rack->r_late) {
4772 		/*
4773 		 * This is harder, we can
4774 		 * compensate some but it
4775 		 * really depends on what
4776 		 * the current pacing time is.
4777 		 */
4778 		if (rack->r_ctl.rc_agg_delayed >= slot) {
4779 			/*
4780 			 * We can't compensate for it all.
4781 			 * And we have to have some time
4782 			 * on the clock. We always have a min
4783 			 * 10 slots (10 x 10 i.e. 100 usecs).
4784 			 */
4785 			if (slot <= HPTS_TICKS_PER_USEC) {
4786 				/* We gain delay */
4787 				rack->r_ctl.rc_agg_delayed += (HPTS_TICKS_PER_USEC - slot);
4788 				slot = HPTS_TICKS_PER_USEC;
4789 			} else {
4790 				/* We take off some */
4791 				rack->r_ctl.rc_agg_delayed -= (slot - HPTS_TICKS_PER_USEC);
4792 				slot = HPTS_TICKS_PER_USEC;
4793 			}
4794 		} else {
4795 			slot -= rack->r_ctl.rc_agg_delayed;
4796 			rack->r_ctl.rc_agg_delayed = 0;
4797 			/* Make sure we have 100 useconds at minimum */
4798 			if (slot < HPTS_TICKS_PER_USEC) {
4799 				rack->r_ctl.rc_agg_delayed = HPTS_TICKS_PER_USEC - slot;
4800 				slot = HPTS_TICKS_PER_USEC;
4801 			}
4802 			if (rack->r_ctl.rc_agg_delayed == 0)
4803 				rack->r_late = 0;
4804 		}
4805 	}
4806 	if (slot) {
4807 		/* We are pacing too */
4808 		rack->r_ctl.rc_hpts_flags |= PACE_PKT_OUTPUT;
4809 	}
4810 	hpts_timeout = rack_timer_start(tp, rack, cts, sup_rack);
4811 #ifdef NETFLIX_EXP_DETECTION
4812 	if (rack->sack_attack_disable &&
4813 	    (slot < tcp_sad_pacing_interval)) {
4814 		/*
4815 		 * We have a potential attacker on
4816 		 * the line. We have possibly some
4817 		 * (or now) pacing time set. We want to
4818 		 * slow down the processing of sacks by some
4819 		 * amount (if it is an attacker). Set the default
4820 		 * slot for attackers in place (unless the orginal
4821 		 * interval is longer). Its stored in
4822 		 * micro-seconds, so lets convert to msecs.
4823 		 */
4824 		slot = tcp_sad_pacing_interval;
4825 	}
4826 #endif
4827 	if (tp->t_flags & TF_DELACK) {
4828 		delayed_ack = TICKS_2_MSEC(tcp_delacktime);
4829 		rack->r_ctl.rc_hpts_flags |= PACE_TMR_DELACK;
4830 	}
4831 	if (delayed_ack && ((hpts_timeout == 0) ||
4832 			    (delayed_ack < hpts_timeout)))
4833 		hpts_timeout = delayed_ack;
4834 	else
4835 		rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_DELACK;
4836 	/*
4837 	 * If no timers are going to run and we will fall off the hptsi
4838 	 * wheel, we resort to a keep-alive timer if its configured.
4839 	 */
4840 	if ((hpts_timeout == 0) &&
4841 	    (slot == 0)) {
4842 		if ((V_tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
4843 		    (tp->t_state <= TCPS_CLOSING)) {
4844 			/*
4845 			 * Ok we have no timer (persists, rack, tlp, rxt  or
4846 			 * del-ack), we don't have segments being paced. So
4847 			 * all that is left is the keepalive timer.
4848 			 */
4849 			if (TCPS_HAVEESTABLISHED(tp->t_state)) {
4850 				/* Get the established keep-alive time */
4851 				hpts_timeout = TP_KEEPIDLE(tp);
4852 			} else {
4853 				/* Get the initial setup keep-alive time */
4854 				hpts_timeout = TP_KEEPINIT(tp);
4855 			}
4856 			rack->r_ctl.rc_hpts_flags |= PACE_TMR_KEEP;
4857 			if (rack->in_probe_rtt) {
4858 				/*
4859 				 * We want to instead not wake up a long time from
4860 				 * now but to wake up about the time we would
4861 				 * exit probe-rtt and initiate a keep-alive ack.
4862 				 * This will get us out of probe-rtt and update
4863 				 * our min-rtt.
4864 				 */
4865 				hpts_timeout = (rack_min_probertt_hold / HPTS_USEC_IN_MSEC);
4866 			}
4867 		}
4868 	}
4869 	if (left && (stopped & (PACE_TMR_KEEP | PACE_TMR_DELACK)) ==
4870 	    (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK)) {
4871 		/*
4872 		 * RACK, TLP, persists and RXT timers all are restartable
4873 		 * based on actions input .. i.e we received a packet (ack
4874 		 * or sack) and that changes things (rw, or snd_una etc).
4875 		 * Thus we can restart them with a new value. For
4876 		 * keep-alive, delayed_ack we keep track of what was left
4877 		 * and restart the timer with a smaller value.
4878 		 */
4879 		if (left < hpts_timeout)
4880 			hpts_timeout = left;
4881 	}
4882 	if (hpts_timeout) {
4883 		/*
4884 		 * Hack alert for now we can't time-out over 2,147,483
4885 		 * seconds (a bit more than 596 hours), which is probably ok
4886 		 * :).
4887 		 */
4888 		if (hpts_timeout > 0x7ffffffe)
4889 			hpts_timeout = 0x7ffffffe;
4890 		rack->r_ctl.rc_timer_exp = cts + hpts_timeout;
4891 	}
4892 	if ((rack->rc_gp_filled == 0) &&
4893 	    (hpts_timeout < slot) &&
4894 	    (rack->r_ctl.rc_hpts_flags & (PACE_TMR_TLP|PACE_TMR_RXT))) {
4895 		/*
4896 		 * We have no good estimate yet for the
4897 		 * old clunky burst mitigation or the
4898 		 * real pacing. And the tlp or rxt is smaller
4899 		 * than the pacing calculation. Lets not
4900 		 * pace that long since we know the calculation
4901 		 * so far is not accurate.
4902 		 */
4903 		slot = hpts_timeout;
4904 	}
4905 	rack->r_ctl.last_pacing_time = slot;
4906 	if (slot) {
4907 		rack->r_ctl.rc_last_output_to = us_cts + slot;
4908 		if (rack->rc_always_pace || rack->r_mbuf_queue) {
4909 			if ((rack->rc_gp_filled == 0) ||
4910 			    rack->pacing_longer_than_rtt) {
4911 				inp->inp_flags2 &= ~(INP_DONT_SACK_QUEUE|INP_MBUF_QUEUE_READY);
4912 			} else {
4913 				inp->inp_flags2 |= INP_MBUF_QUEUE_READY;
4914 				if ((rack->r_ctl.rc_hpts_flags & PACE_TMR_RACK) &&
4915 				    (rack->r_rr_config != 3))
4916 					inp->inp_flags2 |= INP_DONT_SACK_QUEUE;
4917 				else
4918 					inp->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
4919 			}
4920 		}
4921 		if ((rack->use_rack_rr) &&
4922 		    (rack->r_rr_config < 2) &&
4923 		    ((hpts_timeout) && ((hpts_timeout * HPTS_USEC_IN_MSEC) < slot))) {
4924 			/*
4925 			 * Arrange for the hpts to kick back in after the
4926 			 * t-o if the t-o does not cause a send.
4927 			 */
4928 			(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_MS_TO_SLOTS(hpts_timeout),
4929 						   __LINE__, &diag);
4930 			rack_log_hpts_diag(rack, us_cts, &diag, &tv);
4931 			rack_log_to_start(rack, cts, hpts_timeout, slot, 0);
4932 		} else {
4933 			(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_USEC_TO_SLOTS(slot),
4934 						   __LINE__, &diag);
4935 			rack_log_hpts_diag(rack, us_cts, &diag, &tv);
4936 			rack_log_to_start(rack, cts, hpts_timeout, slot, 1);
4937 		}
4938 	} else if (hpts_timeout) {
4939 		if (rack->rc_always_pace || rack->r_mbuf_queue) {
4940 			if (rack->r_ctl.rc_hpts_flags & PACE_TMR_RACK)  {
4941 				/* For a rack timer, don't wake us */
4942 				inp->inp_flags2 |= INP_MBUF_QUEUE_READY;
4943 				if  (rack->r_rr_config != 3)
4944 					inp->inp_flags2 |= INP_DONT_SACK_QUEUE;
4945 				else
4946 					inp->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
4947 			} else {
4948 				/* All other timers wake us up */
4949 				inp->inp_flags2 &= ~INP_MBUF_QUEUE_READY;
4950 				inp->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
4951 			}
4952 		}
4953 		(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_MS_TO_SLOTS(hpts_timeout),
4954 					   __LINE__, &diag);
4955 		rack_log_hpts_diag(rack, us_cts, &diag, &tv);
4956 		rack_log_to_start(rack, cts, hpts_timeout, slot, 0);
4957 	} else {
4958 		/* No timer starting */
4959 #ifdef INVARIANTS
4960 		if (SEQ_GT(tp->snd_max, tp->snd_una)) {
4961 			panic("tp:%p rack:%p tlts:%d cts:%u slot:%u pto:%u -- no timer started?",
4962 			    tp, rack, tot_len_this_send, cts, slot, hpts_timeout);
4963 		}
4964 #endif
4965 	}
4966 	rack->rc_tmr_stopped = 0;
4967 	if (slot)
4968 		rack_log_type_bbrsnd(rack, tot_len_this_send, slot, us_cts, &tv);
4969 }
4970 
4971 /*
4972  * RACK Timer, here we simply do logging and house keeping.
4973  * the normal rack_output() function will call the
4974  * appropriate thing to check if we need to do a RACK retransmit.
4975  * We return 1, saying don't proceed with rack_output only
4976  * when all timers have been stopped (destroyed PCB?).
4977  */
4978 static int
4979 rack_timeout_rack(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
4980 {
4981 	/*
4982 	 * This timer simply provides an internal trigger to send out data.
4983 	 * The check_recovery_mode call will see if there are needed
4984 	 * retransmissions, if so we will enter fast-recovery. The output
4985 	 * call may or may not do the same thing depending on sysctl
4986 	 * settings.
4987 	 */
4988 	struct rack_sendmap *rsm;
4989 	int32_t recovery;
4990 
4991 	if (tp->t_timers->tt_flags & TT_STOPPED) {
4992 		return (1);
4993 	}
4994 	recovery = IN_RECOVERY(tp->t_flags);
4995 	counter_u64_add(rack_to_tot, 1);
4996 	if (rack->r_state && (rack->r_state != tp->t_state))
4997 		rack_set_state(tp, rack);
4998 	rack->rc_on_min_to = 0;
4999 	rsm = rack_check_recovery_mode(tp, cts);
5000 	rack_log_to_event(rack, RACK_TO_FRM_RACK, rsm);
5001 	if (rsm) {
5002 		uint32_t rtt;
5003 
5004 		rack->r_ctl.rc_resend = rsm;
5005 		if (rack->use_rack_rr) {
5006 			/*
5007 			 * Don't accumulate extra pacing delay
5008 			 * we are allowing the rack timer to
5009 			 * over-ride pacing i.e. rrr takes precedence
5010 			 * if the pacing interval is longer than the rrr
5011 			 * time (in other words we get the min pacing
5012 			 * time versus rrr pacing time).
5013 			 */
5014 			rack->r_timer_override = 1;
5015 			rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
5016 		}
5017 		rtt = rack->rc_rack_rtt;
5018 		if (rtt == 0)
5019 			rtt = 1;
5020 		if (rack->rack_no_prr == 0) {
5021 			if ((recovery == 0) &&
5022 			    (rack->r_ctl.rc_prr_sndcnt < ctf_fixed_maxseg(tp))) {
5023 				/*
5024 				 * The rack-timeout that enter's us into recovery
5025 				 * will force out one MSS and set us up so that we
5026 				 * can do one more send in 2*rtt (transitioning the
5027 				 * rack timeout into a rack-tlp).
5028 				 */
5029 				rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
5030 				rack->r_timer_override = 1;
5031 				rack_log_to_prr(rack, 3, 0);
5032 			} else if ((rack->r_ctl.rc_prr_sndcnt < (rsm->r_end - rsm->r_start)) &&
5033 				   rack->use_rack_rr) {
5034 				/*
5035 				 * When a rack timer goes, if the rack rr is
5036 				 * on, arrange it so we can send a full segment
5037 				 * overriding prr (though we pay a price for this
5038 				 * for future new sends).
5039 				 */
5040 				rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
5041 				rack_log_to_prr(rack, 4, 0);
5042 			}
5043 		}
5044 	}
5045 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_RACK;
5046 	if (rsm == NULL) {
5047 		/* restart a timer and return 1 */
5048 		rack_start_hpts_timer(rack, tp, cts,
5049 				      0, 0, 0);
5050 		return (1);
5051 	}
5052 	return (0);
5053 }
5054 
5055 static __inline void
5056 rack_clone_rsm(struct tcp_rack *rack, struct rack_sendmap *nrsm,
5057 	       struct rack_sendmap *rsm, uint32_t start)
5058 {
5059 	int idx;
5060 
5061 	nrsm->r_start = start;
5062 	nrsm->r_end = rsm->r_end;
5063 	nrsm->r_rtr_cnt = rsm->r_rtr_cnt;
5064 	nrsm->r_flags = rsm->r_flags;
5065 	nrsm->r_dupack = rsm->r_dupack;
5066 	nrsm->usec_orig_send = rsm->usec_orig_send;
5067 	nrsm->r_rtr_bytes = 0;
5068 	rsm->r_end = nrsm->r_start;
5069 	nrsm->r_just_ret = rsm->r_just_ret;
5070 	for (idx = 0; idx < nrsm->r_rtr_cnt; idx++) {
5071 		nrsm->r_tim_lastsent[idx] = rsm->r_tim_lastsent[idx];
5072 	}
5073 }
5074 
5075 static struct rack_sendmap *
5076 rack_merge_rsm(struct tcp_rack *rack,
5077 	       struct rack_sendmap *l_rsm,
5078 	       struct rack_sendmap *r_rsm)
5079 {
5080 	/*
5081 	 * We are merging two ack'd RSM's,
5082 	 * the l_rsm is on the left (lower seq
5083 	 * values) and the r_rsm is on the right
5084 	 * (higher seq value). The simplest way
5085 	 * to merge these is to move the right
5086 	 * one into the left. I don't think there
5087 	 * is any reason we need to try to find
5088 	 * the oldest (or last oldest retransmitted).
5089 	 */
5090 	struct rack_sendmap *rm;
5091 
5092 	l_rsm->r_end = r_rsm->r_end;
5093 	if (l_rsm->r_dupack < r_rsm->r_dupack)
5094 		l_rsm->r_dupack = r_rsm->r_dupack;
5095 	if (r_rsm->r_rtr_bytes)
5096 		l_rsm->r_rtr_bytes += r_rsm->r_rtr_bytes;
5097 	if (r_rsm->r_in_tmap) {
5098 		/* This really should not happen */
5099 		TAILQ_REMOVE(&rack->r_ctl.rc_tmap, r_rsm, r_tnext);
5100 		r_rsm->r_in_tmap = 0;
5101 	}
5102 
5103 	/* Now the flags */
5104 	if (r_rsm->r_flags & RACK_HAS_FIN)
5105 		l_rsm->r_flags |= RACK_HAS_FIN;
5106 	if (r_rsm->r_flags & RACK_TLP)
5107 		l_rsm->r_flags |= RACK_TLP;
5108 	if (r_rsm->r_flags & RACK_RWND_COLLAPSED)
5109 		l_rsm->r_flags |= RACK_RWND_COLLAPSED;
5110 	if ((r_rsm->r_flags & RACK_APP_LIMITED)  &&
5111 	    ((l_rsm->r_flags & RACK_APP_LIMITED) == 0)) {
5112 		/*
5113 		 * If both are app-limited then let the
5114 		 * free lower the count. If right is app
5115 		 * limited and left is not, transfer.
5116 		 */
5117 		l_rsm->r_flags |= RACK_APP_LIMITED;
5118 		r_rsm->r_flags &= ~RACK_APP_LIMITED;
5119 		if (r_rsm == rack->r_ctl.rc_first_appl)
5120 			rack->r_ctl.rc_first_appl = l_rsm;
5121 	}
5122 	rm = RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, r_rsm);
5123 #ifdef INVARIANTS
5124 	if (rm != r_rsm) {
5125 		panic("removing head in rack:%p rsm:%p rm:%p",
5126 		      rack, r_rsm, rm);
5127 	}
5128 #endif
5129 	if ((r_rsm->r_limit_type == 0) && (l_rsm->r_limit_type != 0)) {
5130 		/* Transfer the split limit to the map we free */
5131 		r_rsm->r_limit_type = l_rsm->r_limit_type;
5132 		l_rsm->r_limit_type = 0;
5133 	}
5134 	rack_free(rack, r_rsm);
5135 	return(l_rsm);
5136 }
5137 
5138 /*
5139  * TLP Timer, here we simply setup what segment we want to
5140  * have the TLP expire on, the normal rack_output() will then
5141  * send it out.
5142  *
5143  * We return 1, saying don't proceed with rack_output only
5144  * when all timers have been stopped (destroyed PCB?).
5145  */
5146 static int
5147 rack_timeout_tlp(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5148 {
5149 	/*
5150 	 * Tail Loss Probe.
5151 	 */
5152 	struct rack_sendmap *rsm = NULL;
5153 	struct rack_sendmap *insret;
5154 	struct socket *so;
5155 	uint32_t amm, old_prr_snd = 0;
5156 	uint32_t out, avail;
5157 	int collapsed_win = 0;
5158 
5159 	if (tp->t_timers->tt_flags & TT_STOPPED) {
5160 		return (1);
5161 	}
5162 	if (TSTMP_LT(cts, rack->r_ctl.rc_timer_exp)) {
5163 		/* Its not time yet */
5164 		return (0);
5165 	}
5166 	if (ctf_progress_timeout_check(tp, true)) {
5167 		rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
5168 		tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
5169 		return (1);
5170 	}
5171 	/*
5172 	 * A TLP timer has expired. We have been idle for 2 rtts. So we now
5173 	 * need to figure out how to force a full MSS segment out.
5174 	 */
5175 	rack_log_to_event(rack, RACK_TO_FRM_TLP, NULL);
5176 	counter_u64_add(rack_tlp_tot, 1);
5177 	if (rack->r_state && (rack->r_state != tp->t_state))
5178 		rack_set_state(tp, rack);
5179 	so = tp->t_inpcb->inp_socket;
5180 	avail = sbavail(&so->so_snd);
5181 	out = tp->snd_max - tp->snd_una;
5182 	if (out > tp->snd_wnd) {
5183 		/* special case, we need a retransmission */
5184 		collapsed_win = 1;
5185 		goto need_retran;
5186 	}
5187 	/*
5188 	 * Check our send oldest always settings, and if
5189 	 * there is an oldest to send jump to the need_retran.
5190 	 */
5191 	if (rack_always_send_oldest && (TAILQ_EMPTY(&rack->r_ctl.rc_tmap) == 0))
5192 		goto need_retran;
5193 
5194 	if (avail > out) {
5195 		/* New data is available */
5196 		amm = avail - out;
5197 		if (amm > ctf_fixed_maxseg(tp)) {
5198 			amm = ctf_fixed_maxseg(tp);
5199 			if ((amm + out) > tp->snd_wnd) {
5200 				/* We are rwnd limited */
5201 				goto need_retran;
5202 			}
5203 		} else if (amm < ctf_fixed_maxseg(tp)) {
5204 			/* not enough to fill a MTU */
5205 			goto need_retran;
5206 		}
5207 		if (IN_RECOVERY(tp->t_flags)) {
5208 			/* Unlikely */
5209 			if (rack->rack_no_prr == 0) {
5210 				old_prr_snd = rack->r_ctl.rc_prr_sndcnt;
5211 				if (out + amm <= tp->snd_wnd) {
5212 					rack->r_ctl.rc_prr_sndcnt = amm;
5213 					rack_log_to_prr(rack, 4, 0);
5214 				}
5215 			} else
5216 				goto need_retran;
5217 		} else {
5218 			/* Set the send-new override */
5219 			if (out + amm <= tp->snd_wnd)
5220 				rack->r_ctl.rc_tlp_new_data = amm;
5221 			else
5222 				goto need_retran;
5223 		}
5224 		rack->r_ctl.rc_tlpsend = NULL;
5225 		counter_u64_add(rack_tlp_newdata, 1);
5226 		goto send;
5227 	}
5228 need_retran:
5229 	/*
5230 	 * Ok we need to arrange the last un-acked segment to be re-sent, or
5231 	 * optionally the first un-acked segment.
5232 	 */
5233 	if (collapsed_win == 0) {
5234 		if (rack_always_send_oldest)
5235 			rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
5236 		else {
5237 			rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
5238 			if (rsm && (rsm->r_flags & (RACK_ACKED | RACK_HAS_FIN))) {
5239 				rsm = rack_find_high_nonack(rack, rsm);
5240 			}
5241 		}
5242 		if (rsm == NULL) {
5243 			counter_u64_add(rack_tlp_does_nada, 1);
5244 #ifdef TCP_BLACKBOX
5245 			tcp_log_dump_tp_logbuf(tp, "nada counter trips", M_NOWAIT, true);
5246 #endif
5247 			goto out;
5248 		}
5249 	} else {
5250 		/*
5251 		 * We must find the last segment
5252 		 * that was acceptable by the client.
5253 		 */
5254 		RB_FOREACH_REVERSE(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
5255 			if ((rsm->r_flags & RACK_RWND_COLLAPSED) == 0) {
5256 				/* Found one */
5257 				break;
5258 			}
5259 		}
5260 		if (rsm == NULL) {
5261 			/* None? if so send the first */
5262 			rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
5263 			if (rsm == NULL) {
5264 				counter_u64_add(rack_tlp_does_nada, 1);
5265 #ifdef TCP_BLACKBOX
5266 				tcp_log_dump_tp_logbuf(tp, "nada counter trips", M_NOWAIT, true);
5267 #endif
5268 				goto out;
5269 			}
5270 		}
5271 	}
5272 	if ((rsm->r_end - rsm->r_start) > ctf_fixed_maxseg(tp)) {
5273 		/*
5274 		 * We need to split this the last segment in two.
5275 		 */
5276 		struct rack_sendmap *nrsm;
5277 
5278 		nrsm = rack_alloc_full_limit(rack);
5279 		if (nrsm == NULL) {
5280 			/*
5281 			 * No memory to split, we will just exit and punt
5282 			 * off to the RXT timer.
5283 			 */
5284 			counter_u64_add(rack_tlp_does_nada, 1);
5285 			goto out;
5286 		}
5287 		rack_clone_rsm(rack, nrsm, rsm,
5288 			       (rsm->r_end - ctf_fixed_maxseg(tp)));
5289 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
5290 #ifdef INVARIANTS
5291 		if (insret != NULL) {
5292 			panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
5293 			      nrsm, insret, rack, rsm);
5294 		}
5295 #endif
5296 		if (rsm->r_in_tmap) {
5297 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
5298 			nrsm->r_in_tmap = 1;
5299 		}
5300 		rsm->r_flags &= (~RACK_HAS_FIN);
5301 		rsm = nrsm;
5302 	}
5303 	rack->r_ctl.rc_tlpsend = rsm;
5304 send:
5305 	rack->r_timer_override = 1;
5306 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_TLP;
5307 	return (0);
5308 out:
5309 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_TLP;
5310 	return (0);
5311 }
5312 
5313 /*
5314  * Delayed ack Timer, here we simply need to setup the
5315  * ACK_NOW flag and remove the DELACK flag. From there
5316  * the output routine will send the ack out.
5317  *
5318  * We only return 1, saying don't proceed, if all timers
5319  * are stopped (destroyed PCB?).
5320  */
5321 static int
5322 rack_timeout_delack(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5323 {
5324 	if (tp->t_timers->tt_flags & TT_STOPPED) {
5325 		return (1);
5326 	}
5327 	rack_log_to_event(rack, RACK_TO_FRM_DELACK, NULL);
5328 	tp->t_flags &= ~TF_DELACK;
5329 	tp->t_flags |= TF_ACKNOW;
5330 	KMOD_TCPSTAT_INC(tcps_delack);
5331 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_DELACK;
5332 	return (0);
5333 }
5334 
5335 /*
5336  * Persists timer, here we simply send the
5337  * same thing as a keepalive will.
5338  * the one byte send.
5339  *
5340  * We only return 1, saying don't proceed, if all timers
5341  * are stopped (destroyed PCB?).
5342  */
5343 static int
5344 rack_timeout_persist(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5345 {
5346 	struct tcptemp *t_template;
5347 	struct inpcb *inp;
5348 	int32_t retval = 1;
5349 
5350 	inp = tp->t_inpcb;
5351 
5352 	if (tp->t_timers->tt_flags & TT_STOPPED) {
5353 		return (1);
5354 	}
5355 	if (rack->rc_in_persist == 0)
5356 		return (0);
5357 	if (ctf_progress_timeout_check(tp, false)) {
5358 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
5359 		rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
5360 		tcp_set_inp_to_drop(inp, ETIMEDOUT);
5361 		return (1);
5362 	}
5363 	KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
5364 	/*
5365 	 * Persistence timer into zero window. Force a byte to be output, if
5366 	 * possible.
5367 	 */
5368 	KMOD_TCPSTAT_INC(tcps_persisttimeo);
5369 	/*
5370 	 * Hack: if the peer is dead/unreachable, we do not time out if the
5371 	 * window is closed.  After a full backoff, drop the connection if
5372 	 * the idle time (no responses to probes) reaches the maximum
5373 	 * backoff that we would use if retransmitting.
5374 	 */
5375 	if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
5376 	    (ticks - tp->t_rcvtime >= tcp_maxpersistidle ||
5377 	    ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) {
5378 		KMOD_TCPSTAT_INC(tcps_persistdrop);
5379 		retval = 1;
5380 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
5381 		tcp_set_inp_to_drop(rack->rc_inp, ETIMEDOUT);
5382 		goto out;
5383 	}
5384 	if ((sbavail(&rack->rc_inp->inp_socket->so_snd) == 0) &&
5385 	    tp->snd_una == tp->snd_max)
5386 		rack_exit_persist(tp, rack, cts);
5387 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_PERSIT;
5388 	/*
5389 	 * If the user has closed the socket then drop a persisting
5390 	 * connection after a much reduced timeout.
5391 	 */
5392 	if (tp->t_state > TCPS_CLOSE_WAIT &&
5393 	    (ticks - tp->t_rcvtime) >= TCPTV_PERSMAX) {
5394 		retval = 1;
5395 		KMOD_TCPSTAT_INC(tcps_persistdrop);
5396 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
5397 		tcp_set_inp_to_drop(rack->rc_inp, ETIMEDOUT);
5398 		goto out;
5399 	}
5400 	t_template = tcpip_maketemplate(rack->rc_inp);
5401 	if (t_template) {
5402 		/* only set it if we were answered */
5403 		if (rack->forced_ack == 0) {
5404 			rack->forced_ack = 1;
5405 			rack->r_ctl.forced_ack_ts = tcp_get_usecs(NULL);
5406 		}
5407 		tcp_respond(tp, t_template->tt_ipgen,
5408 			    &t_template->tt_t, (struct mbuf *)NULL,
5409 			    tp->rcv_nxt, tp->snd_una - 1, 0);
5410 		/* This sends an ack */
5411 		if (tp->t_flags & TF_DELACK)
5412 			tp->t_flags &= ~TF_DELACK;
5413 		free(t_template, M_TEMP);
5414 	}
5415 	if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
5416 		tp->t_rxtshift++;
5417 out:
5418 	rack_log_to_event(rack, RACK_TO_FRM_PERSIST, NULL);
5419 	rack_start_hpts_timer(rack, tp, cts,
5420 			      0, 0, 0);
5421 	return (retval);
5422 }
5423 
5424 /*
5425  * If a keepalive goes off, we had no other timers
5426  * happening. We always return 1 here since this
5427  * routine either drops the connection or sends
5428  * out a segment with respond.
5429  */
5430 static int
5431 rack_timeout_keepalive(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5432 {
5433 	struct tcptemp *t_template;
5434 	struct inpcb *inp;
5435 
5436 	if (tp->t_timers->tt_flags & TT_STOPPED) {
5437 		return (1);
5438 	}
5439 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_KEEP;
5440 	inp = tp->t_inpcb;
5441 	rack_log_to_event(rack, RACK_TO_FRM_KEEP, NULL);
5442 	/*
5443 	 * Keep-alive timer went off; send something or drop connection if
5444 	 * idle for too long.
5445 	 */
5446 	KMOD_TCPSTAT_INC(tcps_keeptimeo);
5447 	if (tp->t_state < TCPS_ESTABLISHED)
5448 		goto dropit;
5449 	if ((V_tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
5450 	    tp->t_state <= TCPS_CLOSING) {
5451 		if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp))
5452 			goto dropit;
5453 		/*
5454 		 * Send a packet designed to force a response if the peer is
5455 		 * up and reachable: either an ACK if the connection is
5456 		 * still alive, or an RST if the peer has closed the
5457 		 * connection due to timeout or reboot. Using sequence
5458 		 * number tp->snd_una-1 causes the transmitted zero-length
5459 		 * segment to lie outside the receive window; by the
5460 		 * protocol spec, this requires the correspondent TCP to
5461 		 * respond.
5462 		 */
5463 		KMOD_TCPSTAT_INC(tcps_keepprobe);
5464 		t_template = tcpip_maketemplate(inp);
5465 		if (t_template) {
5466 			if (rack->forced_ack == 0) {
5467 				rack->forced_ack = 1;
5468 				rack->r_ctl.forced_ack_ts = tcp_get_usecs(NULL);
5469 			}
5470 			tcp_respond(tp, t_template->tt_ipgen,
5471 			    &t_template->tt_t, (struct mbuf *)NULL,
5472 			    tp->rcv_nxt, tp->snd_una - 1, 0);
5473 			free(t_template, M_TEMP);
5474 		}
5475 	}
5476 	rack_start_hpts_timer(rack, tp, cts, 0, 0, 0);
5477 	return (1);
5478 dropit:
5479 	KMOD_TCPSTAT_INC(tcps_keepdrops);
5480 	tcp_log_end_status(tp, TCP_EI_STATUS_KEEP_MAX);
5481 	tcp_set_inp_to_drop(rack->rc_inp, ETIMEDOUT);
5482 	return (1);
5483 }
5484 
5485 /*
5486  * Retransmit helper function, clear up all the ack
5487  * flags and take care of important book keeping.
5488  */
5489 static void
5490 rack_remxt_tmr(struct tcpcb *tp)
5491 {
5492 	/*
5493 	 * The retransmit timer went off, all sack'd blocks must be
5494 	 * un-acked.
5495 	 */
5496 	struct rack_sendmap *rsm, *trsm = NULL;
5497 	struct tcp_rack *rack;
5498 	int32_t cnt = 0;
5499 
5500 	rack = (struct tcp_rack *)tp->t_fb_ptr;
5501 	rack_timer_cancel(tp, rack, tcp_ts_getticks(), __LINE__);
5502 	rack_log_to_event(rack, RACK_TO_FRM_TMR, NULL);
5503 	if (rack->r_state && (rack->r_state != tp->t_state))
5504 		rack_set_state(tp, rack);
5505 	/*
5506 	 * Ideally we would like to be able to
5507 	 * mark SACK-PASS on anything not acked here.
5508 	 * However, if we do that we would burst out
5509 	 * all that data 1ms apart. This would be unwise,
5510 	 * so for now we will just let the normal rxt timer
5511 	 * and tlp timer take care of it.
5512 	 */
5513 	RB_FOREACH(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
5514 		if (rsm->r_flags & RACK_ACKED) {
5515 			cnt++;
5516 			rsm->r_dupack = 0;
5517 			rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
5518 			if (rsm->r_in_tmap == 0) {
5519 				/* We must re-add it back to the tlist */
5520 				if (trsm == NULL) {
5521 					TAILQ_INSERT_HEAD(&rack->r_ctl.rc_tmap, rsm, r_tnext);
5522 				} else {
5523 					TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, trsm, rsm, r_tnext);
5524 				}
5525 				rsm->r_in_tmap = 1;
5526 			}
5527 		}
5528 		trsm = rsm;
5529 		if (rsm->r_flags & RACK_ACKED)
5530 			rsm->r_flags |= RACK_WAS_ACKED;
5531 		rsm->r_flags &= ~(RACK_ACKED | RACK_SACK_PASSED | RACK_WAS_SACKPASS);
5532 	}
5533 	/* Clear the count (we just un-acked them) */
5534 	rack->r_ctl.rc_sacked = 0;
5535 	rack->r_ctl.rc_agg_delayed = 0;
5536 	rack->r_early = 0;
5537 	rack->r_ctl.rc_agg_early = 0;
5538 	rack->r_late = 0;
5539 	/* Clear the tlp rtx mark */
5540 	rack->r_ctl.rc_resend = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
5541 	rack->r_ctl.rc_prr_sndcnt = 0;
5542 	rack_log_to_prr(rack, 6, 0);
5543 	rack->r_timer_override = 1;
5544 }
5545 
5546 static void
5547 rack_cc_conn_init(struct tcpcb *tp)
5548 {
5549 	struct tcp_rack *rack;
5550 
5551 	rack = (struct tcp_rack *)tp->t_fb_ptr;
5552 	cc_conn_init(tp);
5553 	/*
5554 	 * We want a chance to stay in slowstart as
5555 	 * we create a connection. TCP spec says that
5556 	 * initially ssthresh is infinite. For our
5557 	 * purposes that is the snd_wnd.
5558 	 */
5559 	if (tp->snd_ssthresh < tp->snd_wnd) {
5560 		tp->snd_ssthresh = tp->snd_wnd;
5561 	}
5562 	/*
5563 	 * We also want to assure a IW worth of
5564 	 * data can get inflight.
5565 	 */
5566 	if (rc_init_window(rack) < tp->snd_cwnd)
5567 		tp->snd_cwnd = rc_init_window(rack);
5568 }
5569 
5570 /*
5571  * Re-transmit timeout! If we drop the PCB we will return 1, otherwise
5572  * we will setup to retransmit the lowest seq number outstanding.
5573  */
5574 static int
5575 rack_timeout_rxt(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts)
5576 {
5577 	int32_t rexmt;
5578 	struct inpcb *inp;
5579 	int32_t retval = 0;
5580 	bool isipv6;
5581 
5582 	inp = tp->t_inpcb;
5583 	if (tp->t_timers->tt_flags & TT_STOPPED) {
5584 		return (1);
5585 	}
5586 	if (ctf_progress_timeout_check(tp, false)) {
5587 		tcp_log_end_status(tp, TCP_EI_STATUS_RETRAN);
5588 		rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
5589 		tcp_set_inp_to_drop(inp, ETIMEDOUT);
5590 		return (1);
5591 	}
5592 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_RXT;
5593 	if (TCPS_HAVEESTABLISHED(tp->t_state) &&
5594 	    (tp->snd_una == tp->snd_max)) {
5595 		/* Nothing outstanding .. nothing to do */
5596 		return (0);
5597 	}
5598 	/*
5599 	 * Retransmission timer went off.  Message has not been acked within
5600 	 * retransmit interval.  Back off to a longer retransmit interval
5601 	 * and retransmit one segment.
5602 	 */
5603 	rack_remxt_tmr(tp);
5604 	if ((rack->r_ctl.rc_resend == NULL) ||
5605 	    ((rack->r_ctl.rc_resend->r_flags & RACK_RWND_COLLAPSED) == 0)) {
5606 		/*
5607 		 * If the rwnd collapsed on
5608 		 * the one we are retransmitting
5609 		 * it does not count against the
5610 		 * rxt count.
5611 		 */
5612 		tp->t_rxtshift++;
5613 	}
5614 	if (tp->t_rxtshift > TCP_MAXRXTSHIFT) {
5615 		tp->t_rxtshift = TCP_MAXRXTSHIFT;
5616 		KMOD_TCPSTAT_INC(tcps_timeoutdrop);
5617 		retval = 1;
5618 		tcp_log_end_status(tp, TCP_EI_STATUS_RETRAN);
5619 		tcp_set_inp_to_drop(rack->rc_inp,
5620 		    (tp->t_softerror ? (uint16_t) tp->t_softerror : ETIMEDOUT));
5621 		goto out;
5622 	}
5623 	if (tp->t_state == TCPS_SYN_SENT) {
5624 		/*
5625 		 * If the SYN was retransmitted, indicate CWND to be limited
5626 		 * to 1 segment in cc_conn_init().
5627 		 */
5628 		tp->snd_cwnd = 1;
5629 	} else if (tp->t_rxtshift == 1) {
5630 		/*
5631 		 * first retransmit; record ssthresh and cwnd so they can be
5632 		 * recovered if this turns out to be a "bad" retransmit. A
5633 		 * retransmit is considered "bad" if an ACK for this segment
5634 		 * is received within RTT/2 interval; the assumption here is
5635 		 * that the ACK was already in flight.  See "On Estimating
5636 		 * End-to-End Network Path Properties" by Allman and Paxson
5637 		 * for more details.
5638 		 */
5639 		tp->snd_cwnd_prev = tp->snd_cwnd;
5640 		tp->snd_ssthresh_prev = tp->snd_ssthresh;
5641 		tp->snd_recover_prev = tp->snd_recover;
5642 		if (IN_FASTRECOVERY(tp->t_flags))
5643 			tp->t_flags |= TF_WASFRECOVERY;
5644 		else
5645 			tp->t_flags &= ~TF_WASFRECOVERY;
5646 		if (IN_CONGRECOVERY(tp->t_flags))
5647 			tp->t_flags |= TF_WASCRECOVERY;
5648 		else
5649 			tp->t_flags &= ~TF_WASCRECOVERY;
5650 		tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1));
5651 		tp->t_flags |= TF_PREVVALID;
5652 	} else
5653 		tp->t_flags &= ~TF_PREVVALID;
5654 	KMOD_TCPSTAT_INC(tcps_rexmttimeo);
5655 	if ((tp->t_state == TCPS_SYN_SENT) ||
5656 	    (tp->t_state == TCPS_SYN_RECEIVED))
5657 		rexmt = MSEC_2_TICKS(RACK_INITIAL_RTO * tcp_backoff[tp->t_rxtshift]);
5658 	else
5659 		rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
5660 	TCPT_RANGESET(tp->t_rxtcur, rexmt,
5661 	   max(MSEC_2_TICKS(rack_rto_min), rexmt),
5662 	   MSEC_2_TICKS(rack_rto_max));
5663 	/*
5664 	 * We enter the path for PLMTUD if connection is established or, if
5665 	 * connection is FIN_WAIT_1 status, reason for the last is that if
5666 	 * amount of data we send is very small, we could send it in couple
5667 	 * of packets and process straight to FIN. In that case we won't
5668 	 * catch ESTABLISHED state.
5669 	 */
5670 #ifdef INET6
5671 	isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) ? true : false;
5672 #else
5673 	isipv6 = false;
5674 #endif
5675 	if (((V_tcp_pmtud_blackhole_detect == 1) ||
5676 	    (V_tcp_pmtud_blackhole_detect == 2 && !isipv6) ||
5677 	    (V_tcp_pmtud_blackhole_detect == 3 && isipv6)) &&
5678 	    ((tp->t_state == TCPS_ESTABLISHED) ||
5679 	    (tp->t_state == TCPS_FIN_WAIT_1))) {
5680 		/*
5681 		 * Idea here is that at each stage of mtu probe (usually,
5682 		 * 1448 -> 1188 -> 524) should be given 2 chances to recover
5683 		 * before further clamping down. 'tp->t_rxtshift % 2 == 0'
5684 		 * should take care of that.
5685 		 */
5686 		if (((tp->t_flags2 & (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) ==
5687 		    (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) &&
5688 		    (tp->t_rxtshift >= 2 && tp->t_rxtshift < 6 &&
5689 		    tp->t_rxtshift % 2 == 0)) {
5690 			/*
5691 			 * Enter Path MTU Black-hole Detection mechanism: -
5692 			 * Disable Path MTU Discovery (IP "DF" bit). -
5693 			 * Reduce MTU to lower value than what we negotiated
5694 			 * with peer.
5695 			 */
5696 			if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) == 0) {
5697 				/* Record that we may have found a black hole. */
5698 				tp->t_flags2 |= TF2_PLPMTU_BLACKHOLE;
5699 				/* Keep track of previous MSS. */
5700 				tp->t_pmtud_saved_maxseg = tp->t_maxseg;
5701 			}
5702 
5703 			/*
5704 			 * Reduce the MSS to blackhole value or to the
5705 			 * default in an attempt to retransmit.
5706 			 */
5707 #ifdef INET6
5708 			if (isipv6 &&
5709 			    tp->t_maxseg > V_tcp_v6pmtud_blackhole_mss) {
5710 				/* Use the sysctl tuneable blackhole MSS. */
5711 				tp->t_maxseg = V_tcp_v6pmtud_blackhole_mss;
5712 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated);
5713 			} else if (isipv6) {
5714 				/* Use the default MSS. */
5715 				tp->t_maxseg = V_tcp_v6mssdflt;
5716 				/*
5717 				 * Disable Path MTU Discovery when we switch
5718 				 * to minmss.
5719 				 */
5720 				tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
5721 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
5722 			}
5723 #endif
5724 #if defined(INET6) && defined(INET)
5725 			else
5726 #endif
5727 #ifdef INET
5728 			if (tp->t_maxseg > V_tcp_pmtud_blackhole_mss) {
5729 				/* Use the sysctl tuneable blackhole MSS. */
5730 				tp->t_maxseg = V_tcp_pmtud_blackhole_mss;
5731 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated);
5732 			} else {
5733 				/* Use the default MSS. */
5734 				tp->t_maxseg = V_tcp_mssdflt;
5735 				/*
5736 				 * Disable Path MTU Discovery when we switch
5737 				 * to minmss.
5738 				 */
5739 				tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
5740 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
5741 			}
5742 #endif
5743 		} else {
5744 			/*
5745 			 * If further retransmissions are still unsuccessful
5746 			 * with a lowered MTU, maybe this isn't a blackhole
5747 			 * and we restore the previous MSS and blackhole
5748 			 * detection flags. The limit '6' is determined by
5749 			 * giving each probe stage (1448, 1188, 524) 2
5750 			 * chances to recover.
5751 			 */
5752 			if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) &&
5753 			    (tp->t_rxtshift >= 6)) {
5754 				tp->t_flags2 |= TF2_PLPMTU_PMTUD;
5755 				tp->t_flags2 &= ~TF2_PLPMTU_BLACKHOLE;
5756 				tp->t_maxseg = tp->t_pmtud_saved_maxseg;
5757 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_failed);
5758 			}
5759 		}
5760 	}
5761 	/*
5762 	 * If we backed off this far, our srtt estimate is probably bogus.
5763 	 * Clobber it so we'll take the next rtt measurement as our srtt;
5764 	 * move the current srtt into rttvar to keep the current retransmit
5765 	 * times until then.
5766 	 */
5767 	if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
5768 #ifdef INET6
5769 		if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
5770 			in6_losing(tp->t_inpcb);
5771 		else
5772 #endif
5773 			in_losing(tp->t_inpcb);
5774 		tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
5775 		tp->t_srtt = 0;
5776 	}
5777 	sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
5778 	tp->snd_recover = tp->snd_max;
5779 	tp->t_flags |= TF_ACKNOW;
5780 	tp->t_rtttime = 0;
5781 	rack_cong_signal(tp, NULL, CC_RTO);
5782 out:
5783 	return (retval);
5784 }
5785 
5786 static int
5787 rack_process_timers(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, uint8_t hpts_calling)
5788 {
5789 	int32_t ret = 0;
5790 	int32_t timers = (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK);
5791 
5792 	if (timers == 0) {
5793 		return (0);
5794 	}
5795 	if (tp->t_state == TCPS_LISTEN) {
5796 		/* no timers on listen sockets */
5797 		if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)
5798 			return (0);
5799 		return (1);
5800 	}
5801 	if ((timers & PACE_TMR_RACK) &&
5802 	    rack->rc_on_min_to) {
5803 		/*
5804 		 * For the rack timer when we
5805 		 * are on a min-timeout (which means rrr_conf = 3)
5806 		 * we don't want to check the timer. It may
5807 		 * be going off for a pace and thats ok we
5808 		 * want to send the retransmit (if its ready).
5809 		 *
5810 		 * If its on a normal rack timer (non-min) then
5811 		 * we will check if its expired.
5812 		 */
5813 		goto skip_time_check;
5814 	}
5815 	if (TSTMP_LT(cts, rack->r_ctl.rc_timer_exp)) {
5816 		uint32_t left;
5817 
5818 		if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
5819 			ret = -1;
5820 			rack_log_to_processing(rack, cts, ret, 0);
5821 			return (0);
5822 		}
5823 		if (hpts_calling == 0) {
5824 			/*
5825 			 * A user send or queued mbuf (sack) has called us? We
5826 			 * return 0 and let the pacing guards
5827 			 * deal with it if they should or
5828 			 * should not cause a send.
5829 			 */
5830 			ret = -2;
5831 			rack_log_to_processing(rack, cts, ret, 0);
5832 			return (0);
5833 		}
5834 		/*
5835 		 * Ok our timer went off early and we are not paced false
5836 		 * alarm, go back to sleep.
5837 		 */
5838 		ret = -3;
5839 		left = rack->r_ctl.rc_timer_exp - cts;
5840 		tcp_hpts_insert(tp->t_inpcb, HPTS_MS_TO_SLOTS(left));
5841 		rack_log_to_processing(rack, cts, ret, left);
5842 		return (1);
5843 	}
5844 skip_time_check:
5845 	rack->rc_tmr_stopped = 0;
5846 	rack->r_ctl.rc_hpts_flags &= ~PACE_TMR_MASK;
5847 	if (timers & PACE_TMR_DELACK) {
5848 		ret = rack_timeout_delack(tp, rack, cts);
5849 	} else if (timers & PACE_TMR_RACK) {
5850 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
5851 		ret = rack_timeout_rack(tp, rack, cts);
5852 	} else if (timers & PACE_TMR_TLP) {
5853 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
5854 		ret = rack_timeout_tlp(tp, rack, cts);
5855 	} else if (timers & PACE_TMR_RXT) {
5856 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
5857 		ret = rack_timeout_rxt(tp, rack, cts);
5858 	} else if (timers & PACE_TMR_PERSIT) {
5859 		ret = rack_timeout_persist(tp, rack, cts);
5860 	} else if (timers & PACE_TMR_KEEP) {
5861 		ret = rack_timeout_keepalive(tp, rack, cts);
5862 	}
5863 	rack_log_to_processing(rack, cts, ret, timers);
5864 	return (ret);
5865 }
5866 
5867 static void
5868 rack_timer_cancel(struct tcpcb *tp, struct tcp_rack *rack, uint32_t cts, int line)
5869 {
5870 	struct timeval tv;
5871 	uint32_t us_cts, flags_on_entry;
5872 	uint8_t hpts_removed = 0;
5873 
5874 	flags_on_entry = rack->r_ctl.rc_hpts_flags;
5875 	us_cts = tcp_get_usecs(&tv);
5876 	if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
5877 	    ((TSTMP_GEQ(us_cts, rack->r_ctl.rc_last_output_to)) ||
5878 	     ((tp->snd_max - tp->snd_una) == 0))) {
5879 		tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
5880 		hpts_removed = 1;
5881 		/* If we were not delayed cancel out the flag. */
5882 		if ((tp->snd_max - tp->snd_una) == 0)
5883 			rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
5884 		rack_log_to_cancel(rack, hpts_removed, line, us_cts, &tv, flags_on_entry);
5885 	}
5886 	if (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) {
5887 		rack->rc_tmr_stopped = rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK;
5888 		if (rack->rc_inp->inp_in_hpts &&
5889 		    ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0)) {
5890 			/*
5891 			 * Canceling timer's when we have no output being
5892 			 * paced. We also must remove ourselves from the
5893 			 * hpts.
5894 			 */
5895 			tcp_hpts_remove(rack->rc_inp, HPTS_REMOVE_OUTPUT);
5896 			hpts_removed = 1;
5897 		}
5898 		rack->r_ctl.rc_hpts_flags &= ~(PACE_TMR_MASK);
5899 	}
5900 	if (hpts_removed == 0)
5901 		rack_log_to_cancel(rack, hpts_removed, line, us_cts, &tv, flags_on_entry);
5902 }
5903 
5904 static void
5905 rack_timer_stop(struct tcpcb *tp, uint32_t timer_type)
5906 {
5907 	return;
5908 }
5909 
5910 static int
5911 rack_stopall(struct tcpcb *tp)
5912 {
5913 	struct tcp_rack *rack;
5914 	rack = (struct tcp_rack *)tp->t_fb_ptr;
5915 	rack->t_timers_stopped = 1;
5916 	return (0);
5917 }
5918 
5919 static void
5920 rack_timer_activate(struct tcpcb *tp, uint32_t timer_type, uint32_t delta)
5921 {
5922 	return;
5923 }
5924 
5925 static int
5926 rack_timer_active(struct tcpcb *tp, uint32_t timer_type)
5927 {
5928 	return (0);
5929 }
5930 
5931 static void
5932 rack_stop_all_timers(struct tcpcb *tp)
5933 {
5934 	struct tcp_rack *rack;
5935 
5936 	/*
5937 	 * Assure no timers are running.
5938 	 */
5939 	if (tcp_timer_active(tp, TT_PERSIST)) {
5940 		/* We enter in persists, set the flag appropriately */
5941 		rack = (struct tcp_rack *)tp->t_fb_ptr;
5942 		rack->rc_in_persist = 1;
5943 	}
5944 	tcp_timer_suspend(tp, TT_PERSIST);
5945 	tcp_timer_suspend(tp, TT_REXMT);
5946 	tcp_timer_suspend(tp, TT_KEEP);
5947 	tcp_timer_suspend(tp, TT_DELACK);
5948 }
5949 
5950 static void
5951 rack_update_rsm(struct tcpcb *tp, struct tcp_rack *rack,
5952     struct rack_sendmap *rsm, uint32_t ts)
5953 {
5954 	int32_t idx;
5955 
5956 	rsm->r_rtr_cnt++;
5957 	rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
5958 	rsm->r_dupack = 0;
5959 	if (rsm->r_rtr_cnt > RACK_NUM_OF_RETRANS) {
5960 		rsm->r_rtr_cnt = RACK_NUM_OF_RETRANS;
5961 		rsm->r_flags |= RACK_OVERMAX;
5962 	}
5963 	if ((rsm->r_rtr_cnt > 1) && ((rsm->r_flags & RACK_TLP) == 0)) {
5964 		rack->r_ctl.rc_holes_rxt += (rsm->r_end - rsm->r_start);
5965 		rsm->r_rtr_bytes += (rsm->r_end - rsm->r_start);
5966 	}
5967 	idx = rsm->r_rtr_cnt - 1;
5968 	rsm->r_tim_lastsent[idx] = ts;
5969 	if (rsm->r_flags & RACK_ACKED) {
5970 		/* Problably MTU discovery messing with us */
5971 		rsm->r_flags &= ~RACK_ACKED;
5972 		rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
5973 	}
5974 	if (rsm->r_in_tmap) {
5975 		TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
5976 		rsm->r_in_tmap = 0;
5977 	}
5978 	TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext);
5979 	rsm->r_in_tmap = 1;
5980 	if (rsm->r_flags & RACK_SACK_PASSED) {
5981 		/* We have retransmitted due to the SACK pass */
5982 		rsm->r_flags &= ~RACK_SACK_PASSED;
5983 		rsm->r_flags |= RACK_WAS_SACKPASS;
5984 	}
5985 }
5986 
5987 static uint32_t
5988 rack_update_entry(struct tcpcb *tp, struct tcp_rack *rack,
5989     struct rack_sendmap *rsm, uint32_t ts, int32_t *lenp)
5990 {
5991 	/*
5992 	 * We (re-)transmitted starting at rsm->r_start for some length
5993 	 * (possibly less than r_end.
5994 	 */
5995 	struct rack_sendmap *nrsm, *insret;
5996 	uint32_t c_end;
5997 	int32_t len;
5998 
5999 	len = *lenp;
6000 	c_end = rsm->r_start + len;
6001 	if (SEQ_GEQ(c_end, rsm->r_end)) {
6002 		/*
6003 		 * We retransmitted the whole piece or more than the whole
6004 		 * slopping into the next rsm.
6005 		 */
6006 		rack_update_rsm(tp, rack, rsm, ts);
6007 		if (c_end == rsm->r_end) {
6008 			*lenp = 0;
6009 			return (0);
6010 		} else {
6011 			int32_t act_len;
6012 
6013 			/* Hangs over the end return whats left */
6014 			act_len = rsm->r_end - rsm->r_start;
6015 			*lenp = (len - act_len);
6016 			return (rsm->r_end);
6017 		}
6018 		/* We don't get out of this block. */
6019 	}
6020 	/*
6021 	 * Here we retransmitted less than the whole thing which means we
6022 	 * have to split this into what was transmitted and what was not.
6023 	 */
6024 	nrsm = rack_alloc_full_limit(rack);
6025 	if (nrsm == NULL) {
6026 		/*
6027 		 * We can't get memory, so lets not proceed.
6028 		 */
6029 		*lenp = 0;
6030 		return (0);
6031 	}
6032 	/*
6033 	 * So here we are going to take the original rsm and make it what we
6034 	 * retransmitted. nrsm will be the tail portion we did not
6035 	 * retransmit. For example say the chunk was 1, 11 (10 bytes). And
6036 	 * we retransmitted 5 bytes i.e. 1, 5. The original piece shrinks to
6037 	 * 1, 6 and the new piece will be 6, 11.
6038 	 */
6039 	rack_clone_rsm(rack, nrsm, rsm, c_end);
6040 	nrsm->r_dupack = 0;
6041 	rack_log_retran_reason(rack, nrsm, __LINE__, 0, 2);
6042 	insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
6043 #ifdef INVARIANTS
6044 	if (insret != NULL) {
6045 		panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
6046 		      nrsm, insret, rack, rsm);
6047 	}
6048 #endif
6049 	if (rsm->r_in_tmap) {
6050 		TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
6051 		nrsm->r_in_tmap = 1;
6052 	}
6053 	rsm->r_flags &= (~RACK_HAS_FIN);
6054 	rack_update_rsm(tp, rack, rsm, ts);
6055 	*lenp = 0;
6056 	return (0);
6057 }
6058 
6059 static void
6060 rack_log_output(struct tcpcb *tp, struct tcpopt *to, int32_t len,
6061     uint32_t seq_out, uint8_t th_flags, int32_t err, uint32_t ts,
6062     uint8_t pass, struct rack_sendmap *hintrsm, uint32_t us_cts)
6063 {
6064 	struct tcp_rack *rack;
6065 	struct rack_sendmap *rsm, *nrsm, *insret, fe;
6066 	register uint32_t snd_max, snd_una;
6067 
6068 	/*
6069 	 * Add to the RACK log of packets in flight or retransmitted. If
6070 	 * there is a TS option we will use the TS echoed, if not we will
6071 	 * grab a TS.
6072 	 *
6073 	 * Retransmissions will increment the count and move the ts to its
6074 	 * proper place. Note that if options do not include TS's then we
6075 	 * won't be able to effectively use the ACK for an RTT on a retran.
6076 	 *
6077 	 * Notes about r_start and r_end. Lets consider a send starting at
6078 	 * sequence 1 for 10 bytes. In such an example the r_start would be
6079 	 * 1 (starting sequence) but the r_end would be r_start+len i.e. 11.
6080 	 * This means that r_end is actually the first sequence for the next
6081 	 * slot (11).
6082 	 *
6083 	 */
6084 	/*
6085 	 * If err is set what do we do XXXrrs? should we not add the thing?
6086 	 * -- i.e. return if err != 0 or should we pretend we sent it? --
6087 	 * i.e. proceed with add ** do this for now.
6088 	 */
6089 	INP_WLOCK_ASSERT(tp->t_inpcb);
6090 	if (err)
6091 		/*
6092 		 * We don't log errors -- we could but snd_max does not
6093 		 * advance in this case either.
6094 		 */
6095 		return;
6096 
6097 	if (th_flags & TH_RST) {
6098 		/*
6099 		 * We don't log resets and we return immediately from
6100 		 * sending
6101 		 */
6102 		return;
6103 	}
6104 	rack = (struct tcp_rack *)tp->t_fb_ptr;
6105 	snd_una = tp->snd_una;
6106 	if (SEQ_LEQ((seq_out + len), snd_una)) {
6107 		/* Are sending an old segment to induce an ack (keep-alive)? */
6108 		return;
6109 	}
6110 	if (SEQ_LT(seq_out, snd_una)) {
6111 		/* huh? should we panic? */
6112 		uint32_t end;
6113 
6114 		end = seq_out + len;
6115 		seq_out = snd_una;
6116 		if (SEQ_GEQ(end, seq_out))
6117 			len = end - seq_out;
6118 		else
6119 			len = 0;
6120 	}
6121 	snd_max = tp->snd_max;
6122 	if (th_flags & (TH_SYN | TH_FIN)) {
6123 		/*
6124 		 * The call to rack_log_output is made before bumping
6125 		 * snd_max. This means we can record one extra byte on a SYN
6126 		 * or FIN if seq_out is adding more on and a FIN is present
6127 		 * (and we are not resending).
6128 		 */
6129 		if ((th_flags & TH_SYN) && (seq_out == tp->iss))
6130 			len++;
6131 		if (th_flags & TH_FIN)
6132 			len++;
6133 		if (SEQ_LT(snd_max, tp->snd_nxt)) {
6134 			/*
6135 			 * The add/update as not been done for the FIN/SYN
6136 			 * yet.
6137 			 */
6138 			snd_max = tp->snd_nxt;
6139 		}
6140 	}
6141 	if (len == 0) {
6142 		/* We don't log zero window probes */
6143 		return;
6144 	}
6145 	rack->r_ctl.rc_time_last_sent = ts;
6146 	if (IN_RECOVERY(tp->t_flags)) {
6147 		rack->r_ctl.rc_prr_out += len;
6148 	}
6149 	/* First question is it a retransmission or new? */
6150 	if (seq_out == snd_max) {
6151 		/* Its new */
6152 again:
6153 		rsm = rack_alloc(rack);
6154 		if (rsm == NULL) {
6155 			/*
6156 			 * Hmm out of memory and the tcb got destroyed while
6157 			 * we tried to wait.
6158 			 */
6159 			return;
6160 		}
6161 		if (th_flags & TH_FIN) {
6162 			rsm->r_flags = RACK_HAS_FIN;
6163 		} else {
6164 			rsm->r_flags = 0;
6165 		}
6166 		rsm->r_tim_lastsent[0] = ts;
6167 		rsm->r_rtr_cnt = 1;
6168 		rsm->r_rtr_bytes = 0;
6169 		rsm->usec_orig_send = us_cts;
6170 		if (th_flags & TH_SYN) {
6171 			/* The data space is one beyond snd_una */
6172 			rsm->r_flags |= RACK_HAS_SIN;
6173 			rsm->r_start = seq_out + 1;
6174 			rsm->r_end = rsm->r_start + (len - 1);
6175 		} else {
6176 			/* Normal case */
6177 			rsm->r_start = seq_out;
6178 			rsm->r_end = rsm->r_start + len;
6179 		}
6180 		rsm->r_dupack = 0;
6181 		rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
6182 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
6183 #ifdef INVARIANTS
6184 		if (insret != NULL) {
6185 			panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
6186 			      nrsm, insret, rack, rsm);
6187 		}
6188 #endif
6189 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext);
6190 		rsm->r_in_tmap = 1;
6191 		/*
6192 		 * Special case detection, is there just a single
6193 		 * packet outstanding when we are not in recovery?
6194 		 *
6195 		 * If this is true mark it so.
6196 		 */
6197 		if ((IN_RECOVERY(tp->t_flags) == 0) &&
6198 		    (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) == ctf_fixed_maxseg(tp))) {
6199 			struct rack_sendmap *prsm;
6200 
6201 			prsm = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
6202 			if (prsm)
6203 				prsm->r_one_out_nr = 1;
6204 		}
6205 		return;
6206 	}
6207 	/*
6208 	 * If we reach here its a retransmission and we need to find it.
6209 	 */
6210 	memset(&fe, 0, sizeof(fe));
6211 more:
6212 	if (hintrsm && (hintrsm->r_start == seq_out)) {
6213 		rsm = hintrsm;
6214 		hintrsm = NULL;
6215 	} else {
6216 		/* No hints sorry */
6217 		rsm = NULL;
6218 	}
6219 	if ((rsm) && (rsm->r_start == seq_out)) {
6220 		seq_out = rack_update_entry(tp, rack, rsm, ts, &len);
6221 		if (len == 0) {
6222 			return;
6223 		} else {
6224 			goto more;
6225 		}
6226 	}
6227 	/* Ok it was not the last pointer go through it the hard way. */
6228 refind:
6229 	fe.r_start = seq_out;
6230 	rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
6231 	if (rsm) {
6232 		if (rsm->r_start == seq_out) {
6233 			seq_out = rack_update_entry(tp, rack, rsm, ts, &len);
6234 			if (len == 0) {
6235 				return;
6236 			} else {
6237 				goto refind;
6238 			}
6239 		}
6240 		if (SEQ_GEQ(seq_out, rsm->r_start) && SEQ_LT(seq_out, rsm->r_end)) {
6241 			/* Transmitted within this piece */
6242 			/*
6243 			 * Ok we must split off the front and then let the
6244 			 * update do the rest
6245 			 */
6246 			nrsm = rack_alloc_full_limit(rack);
6247 			if (nrsm == NULL) {
6248 				rack_update_rsm(tp, rack, rsm, ts);
6249 				return;
6250 			}
6251 			/*
6252 			 * copy rsm to nrsm and then trim the front of rsm
6253 			 * to not include this part.
6254 			 */
6255 			rack_clone_rsm(rack, nrsm, rsm, seq_out);
6256 			insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
6257 #ifdef INVARIANTS
6258 			if (insret != NULL) {
6259 				panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
6260 				      nrsm, insret, rack, rsm);
6261 			}
6262 #endif
6263 			if (rsm->r_in_tmap) {
6264 				TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
6265 				nrsm->r_in_tmap = 1;
6266 			}
6267 			rsm->r_flags &= (~RACK_HAS_FIN);
6268 			seq_out = rack_update_entry(tp, rack, nrsm, ts, &len);
6269 			if (len == 0) {
6270 				return;
6271 			} else if (len > 0)
6272 				goto refind;
6273 		}
6274 	}
6275 	/*
6276 	 * Hmm not found in map did they retransmit both old and on into the
6277 	 * new?
6278 	 */
6279 	if (seq_out == tp->snd_max) {
6280 		goto again;
6281 	} else if (SEQ_LT(seq_out, tp->snd_max)) {
6282 #ifdef INVARIANTS
6283 		printf("seq_out:%u len:%d snd_una:%u snd_max:%u -- but rsm not found?\n",
6284 		    seq_out, len, tp->snd_una, tp->snd_max);
6285 		printf("Starting Dump of all rack entries\n");
6286 		RB_FOREACH(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
6287 			printf("rsm:%p start:%u end:%u\n",
6288 			    rsm, rsm->r_start, rsm->r_end);
6289 		}
6290 		printf("Dump complete\n");
6291 		panic("seq_out not found rack:%p tp:%p",
6292 		    rack, tp);
6293 #endif
6294 	} else {
6295 #ifdef INVARIANTS
6296 		/*
6297 		 * Hmm beyond sndmax? (only if we are using the new rtt-pack
6298 		 * flag)
6299 		 */
6300 		panic("seq_out:%u(%d) is beyond snd_max:%u tp:%p",
6301 		    seq_out, len, tp->snd_max, tp);
6302 #endif
6303 	}
6304 }
6305 
6306 /*
6307  * Record one of the RTT updates from an ack into
6308  * our sample structure.
6309  */
6310 
6311 static void
6312 tcp_rack_xmit_timer(struct tcp_rack *rack, int32_t rtt, uint32_t len, uint32_t us_rtt,
6313 		    int confidence, struct rack_sendmap *rsm, uint16_t rtrcnt)
6314 {
6315 	if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) ||
6316 	    (rack->r_ctl.rack_rs.rs_rtt_lowest > rtt)) {
6317 		rack->r_ctl.rack_rs.rs_rtt_lowest = rtt;
6318 	}
6319 	if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) ||
6320 	    (rack->r_ctl.rack_rs.rs_rtt_highest < rtt)) {
6321 		rack->r_ctl.rack_rs.rs_rtt_highest = rtt;
6322 	}
6323 	if (rack->rc_tp->t_flags & TF_GPUTINPROG) {
6324 	    if (us_rtt < rack->r_ctl.rc_gp_lowrtt)
6325 		rack->r_ctl.rc_gp_lowrtt = us_rtt;
6326 	    if (rack->rc_tp->snd_wnd > rack->r_ctl.rc_gp_high_rwnd)
6327 		    rack->r_ctl.rc_gp_high_rwnd = rack->rc_tp->snd_wnd;
6328 	}
6329 	if ((confidence == 1) &&
6330 	    ((rsm == NULL) ||
6331 	     (rsm->r_just_ret) ||
6332 	     (rsm->r_one_out_nr &&
6333 	      len < (ctf_fixed_maxseg(rack->rc_tp) * 2)))) {
6334 		/*
6335 		 * If the rsm had a just return
6336 		 * hit it then we can't trust the
6337 		 * rtt measurement for buffer deterimination
6338 		 * Note that a confidence of 2, indicates
6339 		 * SACK'd which overrides the r_just_ret or
6340 		 * the r_one_out_nr. If it was a CUM-ACK and
6341 		 * we had only two outstanding, but get an
6342 		 * ack for only 1. Then that also lowers our
6343 		 * confidence.
6344 		 */
6345 		confidence = 0;
6346 	}
6347 	if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY) ||
6348 	    (rack->r_ctl.rack_rs.rs_us_rtt > us_rtt)) {
6349 		if (rack->r_ctl.rack_rs.confidence == 0) {
6350 			/*
6351 			 * We take anything with no current confidence
6352 			 * saved.
6353 			 */
6354 			rack->r_ctl.rack_rs.rs_us_rtt = us_rtt;
6355 			rack->r_ctl.rack_rs.confidence = confidence;
6356 			rack->r_ctl.rack_rs.rs_us_rtrcnt = rtrcnt;
6357 		} else if (confidence || rack->r_ctl.rack_rs.confidence) {
6358 			/*
6359 			 * Once we have a confident number,
6360 			 * we can update it with a smaller
6361 			 * value since this confident number
6362 			 * may include the DSACK time until
6363 			 * the next segment (the second one) arrived.
6364 			 */
6365 			rack->r_ctl.rack_rs.rs_us_rtt = us_rtt;
6366 			rack->r_ctl.rack_rs.confidence = confidence;
6367 			rack->r_ctl.rack_rs.rs_us_rtrcnt = rtrcnt;
6368 		}
6369 	}
6370 	rack_log_rtt_upd(rack->rc_tp, rack, us_rtt, len, rsm, confidence);
6371 	rack->r_ctl.rack_rs.rs_flags = RACK_RTT_VALID;
6372 	rack->r_ctl.rack_rs.rs_rtt_tot += rtt;
6373 	rack->r_ctl.rack_rs.rs_rtt_cnt++;
6374 }
6375 
6376 /*
6377  * Collect new round-trip time estimate
6378  * and update averages and current timeout.
6379  */
6380 static void
6381 tcp_rack_xmit_timer_commit(struct tcp_rack *rack, struct tcpcb *tp)
6382 {
6383 	int32_t delta;
6384 	uint32_t o_srtt, o_var;
6385 	int32_t hrtt_up = 0;
6386 	int32_t rtt;
6387 
6388 	if (rack->r_ctl.rack_rs.rs_flags & RACK_RTT_EMPTY)
6389 		/* No valid sample */
6390 		return;
6391 	if (rack->r_ctl.rc_rate_sample_method == USE_RTT_LOW) {
6392 		/* We are to use the lowest RTT seen in a single ack */
6393 		rtt = rack->r_ctl.rack_rs.rs_rtt_lowest;
6394 	} else if (rack->r_ctl.rc_rate_sample_method == USE_RTT_HIGH) {
6395 		/* We are to use the highest RTT seen in a single ack */
6396 		rtt = rack->r_ctl.rack_rs.rs_rtt_highest;
6397 	} else if (rack->r_ctl.rc_rate_sample_method == USE_RTT_AVG) {
6398 		/* We are to use the average RTT seen in a single ack */
6399 		rtt = (int32_t)(rack->r_ctl.rack_rs.rs_rtt_tot /
6400 				(uint64_t)rack->r_ctl.rack_rs.rs_rtt_cnt);
6401 	} else {
6402 #ifdef INVARIANTS
6403 		panic("Unknown rtt variant %d", rack->r_ctl.rc_rate_sample_method);
6404 #endif
6405 		return;
6406 	}
6407 	if (rtt == 0)
6408 		rtt = 1;
6409 	if (rack->rc_gp_rtt_set == 0) {
6410 		/*
6411 		 * With no RTT we have to accept
6412 		 * even one we are not confident of.
6413 		 */
6414 		rack->r_ctl.rc_gp_srtt = rack->r_ctl.rack_rs.rs_us_rtt;
6415 		rack->rc_gp_rtt_set = 1;
6416 	} else if (rack->r_ctl.rack_rs.confidence) {
6417 		/* update the running gp srtt */
6418 		rack->r_ctl.rc_gp_srtt -= (rack->r_ctl.rc_gp_srtt/8);
6419 		rack->r_ctl.rc_gp_srtt += rack->r_ctl.rack_rs.rs_us_rtt / 8;
6420 	}
6421 	if (rack->r_ctl.rack_rs.confidence) {
6422 		/*
6423 		 * record the low and high for highly buffered path computation,
6424 		 * we only do this if we are confident (not a retransmission).
6425 		 */
6426 		if (rack->r_ctl.rc_highest_us_rtt < rack->r_ctl.rack_rs.rs_us_rtt) {
6427 			rack->r_ctl.rc_highest_us_rtt = rack->r_ctl.rack_rs.rs_us_rtt;
6428 			hrtt_up = 1;
6429 		}
6430 		if (rack->rc_highly_buffered == 0) {
6431 			/*
6432 			 * Currently once we declare a path has
6433 			 * highly buffered there is no going
6434 			 * back, which may be a problem...
6435 			 */
6436 			if ((rack->r_ctl.rc_highest_us_rtt / rack->r_ctl.rc_lowest_us_rtt) > rack_hbp_thresh) {
6437 				rack_log_rtt_shrinks(rack, rack->r_ctl.rack_rs.rs_us_rtt,
6438 						     rack->r_ctl.rc_highest_us_rtt,
6439 						     rack->r_ctl.rc_lowest_us_rtt,
6440 						     RACK_RTTS_SEEHBP);
6441 				rack->rc_highly_buffered = 1;
6442 			}
6443 		}
6444 	}
6445 	if ((rack->r_ctl.rack_rs.confidence) ||
6446 	    (rack->r_ctl.rack_rs.rs_us_rtrcnt == 1)) {
6447 		/*
6448 		 * If we are highly confident of it <or> it was
6449 		 * never retransmitted we accept it as the last us_rtt.
6450 		 */
6451 		rack->r_ctl.rc_last_us_rtt = rack->r_ctl.rack_rs.rs_us_rtt;
6452 		/* The lowest rtt can be set if its was not retransmited */
6453 		if (rack->r_ctl.rc_lowest_us_rtt > rack->r_ctl.rack_rs.rs_us_rtt) {
6454 			rack->r_ctl.rc_lowest_us_rtt = rack->r_ctl.rack_rs.rs_us_rtt;
6455 			if (rack->r_ctl.rc_lowest_us_rtt == 0)
6456 				rack->r_ctl.rc_lowest_us_rtt = 1;
6457 		}
6458 	}
6459 	rack_log_rtt_sample(rack, rtt);
6460 	o_srtt = tp->t_srtt;
6461 	o_var = tp->t_rttvar;
6462 	rack = (struct tcp_rack *)tp->t_fb_ptr;
6463 	if (tp->t_srtt != 0) {
6464 		/*
6465 		 * srtt is stored as fixed point with 5 bits after the
6466 		 * binary point (i.e., scaled by 8).  The following magic is
6467 		 * equivalent to the smoothing algorithm in rfc793 with an
6468 		 * alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed point).
6469 		 * Adjust rtt to origin 0.
6470 		 */
6471 		delta = ((rtt - 1) << TCP_DELTA_SHIFT)
6472 		    - (tp->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT));
6473 
6474 		tp->t_srtt += delta;
6475 		if (tp->t_srtt <= 0)
6476 			tp->t_srtt = 1;
6477 
6478 		/*
6479 		 * We accumulate a smoothed rtt variance (actually, a
6480 		 * smoothed mean difference), then set the retransmit timer
6481 		 * to smoothed rtt + 4 times the smoothed variance. rttvar
6482 		 * is stored as fixed point with 4 bits after the binary
6483 		 * point (scaled by 16).  The following is equivalent to
6484 		 * rfc793 smoothing with an alpha of .75 (rttvar =
6485 		 * rttvar*3/4 + |delta| / 4).  This replaces rfc793's
6486 		 * wired-in beta.
6487 		 */
6488 		if (delta < 0)
6489 			delta = -delta;
6490 		delta -= tp->t_rttvar >> (TCP_RTTVAR_SHIFT - TCP_DELTA_SHIFT);
6491 		tp->t_rttvar += delta;
6492 		if (tp->t_rttvar <= 0)
6493 			tp->t_rttvar = 1;
6494 		if (tp->t_rttbest > tp->t_srtt + tp->t_rttvar)
6495 			tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
6496 	} else {
6497 		/*
6498 		 * No rtt measurement yet - use the unsmoothed rtt. Set the
6499 		 * variance to half the rtt (so our first retransmit happens
6500 		 * at 3*rtt).
6501 		 */
6502 		tp->t_srtt = rtt << TCP_RTT_SHIFT;
6503 		tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT - 1);
6504 		tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
6505 	}
6506 	KMOD_TCPSTAT_INC(tcps_rttupdated);
6507 	tp->t_rttupdated++;
6508 #ifdef STATS
6509 	stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, rtt));
6510 #endif
6511 	tp->t_rxtshift = 0;
6512 
6513 	/*
6514 	 * the retransmit should happen at rtt + 4 * rttvar. Because of the
6515 	 * way we do the smoothing, srtt and rttvar will each average +1/2
6516 	 * tick of bias.  When we compute the retransmit timer, we want 1/2
6517 	 * tick of rounding and 1 extra tick because of +-1/2 tick
6518 	 * uncertainty in the firing of the timer.  The bias will give us
6519 	 * exactly the 1.5 tick we need.  But, because the bias is
6520 	 * statistical, we have to test that we don't drop below the minimum
6521 	 * feasible timer (which is 2 ticks).
6522 	 */
6523 	TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
6524 	   max(MSEC_2_TICKS(rack_rto_min), rtt + 2), MSEC_2_TICKS(rack_rto_max));
6525 	tp->t_softerror = 0;
6526 }
6527 
6528 static void
6529 rack_earlier_retran(struct tcpcb *tp, struct rack_sendmap *rsm,
6530     uint32_t t, uint32_t cts)
6531 {
6532 	/*
6533 	 * For this RSM, we acknowledged the data from a previous
6534 	 * transmission, not the last one we made. This means we did a false
6535 	 * retransmit.
6536 	 */
6537 	struct tcp_rack *rack;
6538 
6539 	if (rsm->r_flags & RACK_HAS_FIN) {
6540 		/*
6541 		 * The sending of the FIN often is multiple sent when we
6542 		 * have everything outstanding ack'd. We ignore this case
6543 		 * since its over now.
6544 		 */
6545 		return;
6546 	}
6547 	if (rsm->r_flags & RACK_TLP) {
6548 		/*
6549 		 * We expect TLP's to have this occur.
6550 		 */
6551 		return;
6552 	}
6553 	rack = (struct tcp_rack *)tp->t_fb_ptr;
6554 	/* should we undo cc changes and exit recovery? */
6555 	if (IN_RECOVERY(tp->t_flags)) {
6556 		if (rack->r_ctl.rc_rsm_start == rsm->r_start) {
6557 			/*
6558 			 * Undo what we ratched down and exit recovery if
6559 			 * possible
6560 			 */
6561 			EXIT_RECOVERY(tp->t_flags);
6562 			tp->snd_recover = tp->snd_una;
6563 			if (rack->r_ctl.rc_cwnd_at > tp->snd_cwnd)
6564 				tp->snd_cwnd = rack->r_ctl.rc_cwnd_at;
6565 			if (rack->r_ctl.rc_ssthresh_at > tp->snd_ssthresh)
6566 				tp->snd_ssthresh = rack->r_ctl.rc_ssthresh_at;
6567 		}
6568 	}
6569 	if (rsm->r_flags & RACK_WAS_SACKPASS) {
6570 		/*
6571 		 * We retransmitted based on a sack and the earlier
6572 		 * retransmission ack'd it - re-ordering is occuring.
6573 		 */
6574 		counter_u64_add(rack_reorder_seen, 1);
6575 		rack->r_ctl.rc_reorder_ts = cts;
6576 	}
6577 	counter_u64_add(rack_badfr, 1);
6578 	counter_u64_add(rack_badfr_bytes, (rsm->r_end - rsm->r_start));
6579 }
6580 
6581 static void
6582 rack_apply_updated_usrtt(struct tcp_rack *rack, uint32_t us_rtt, uint32_t us_cts)
6583 {
6584 	/*
6585 	 * Apply to filter the inbound us-rtt at us_cts.
6586 	 */
6587 	uint32_t old_rtt;
6588 
6589 	old_rtt = get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt);
6590 	apply_filter_min_small(&rack->r_ctl.rc_gp_min_rtt,
6591 			       us_rtt, us_cts);
6592 	if (rack->r_ctl.last_pacing_time &&
6593 	    rack->rc_gp_dyn_mul &&
6594 	    (rack->r_ctl.last_pacing_time > us_rtt))
6595 		rack->pacing_longer_than_rtt = 1;
6596 	else
6597 		rack->pacing_longer_than_rtt = 0;
6598 	if (old_rtt > us_rtt) {
6599 		/* We just hit a new lower rtt time */
6600 		rack_log_rtt_shrinks(rack,  us_cts,  old_rtt,
6601 				     __LINE__, RACK_RTTS_NEWRTT);
6602 		/*
6603 		 * Only count it if its lower than what we saw within our
6604 		 * calculated range.
6605 		 */
6606 		if ((old_rtt - us_rtt) > rack_min_rtt_movement) {
6607 			if (rack_probertt_lower_within &&
6608 			    rack->rc_gp_dyn_mul &&
6609 			    (rack->use_fixed_rate == 0) &&
6610 			    (rack->rc_always_pace)) {
6611 				/*
6612 				 * We are seeing a new lower rtt very close
6613 				 * to the time that we would have entered probe-rtt.
6614 				 * This is probably due to the fact that a peer flow
6615 				 * has entered probe-rtt. Lets go in now too.
6616 				 */
6617 				uint32_t val;
6618 
6619 				val = rack_probertt_lower_within * rack_time_between_probertt;
6620 				val /= 100;
6621 				if ((rack->in_probe_rtt == 0)  &&
6622 				    ((us_cts - rack->r_ctl.rc_lower_rtt_us_cts) >= (rack_time_between_probertt - val)))	{
6623 					rack_enter_probertt(rack, us_cts);
6624 				}
6625 			}
6626 			rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
6627 		}
6628 	}
6629 }
6630 
6631 static int
6632 rack_update_rtt(struct tcpcb *tp, struct tcp_rack *rack,
6633     struct rack_sendmap *rsm, struct tcpopt *to, uint32_t cts, int32_t ack_type, tcp_seq th_ack)
6634 {
6635 	int32_t i;
6636 	uint32_t t, len_acked;
6637 
6638 	if ((rsm->r_flags & RACK_ACKED) ||
6639 	    (rsm->r_flags & RACK_WAS_ACKED))
6640 		/* Already done */
6641 		return (0);
6642 
6643 	if (ack_type == CUM_ACKED) {
6644 		if (SEQ_GT(th_ack, rsm->r_end))
6645 			len_acked = rsm->r_end - rsm->r_start;
6646 		else
6647 			len_acked = th_ack - rsm->r_start;
6648 	} else
6649 		len_acked = rsm->r_end - rsm->r_start;
6650 	if (rsm->r_rtr_cnt == 1) {
6651 		uint32_t us_rtt;
6652 
6653 		t = cts - rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
6654 		if ((int)t <= 0)
6655 			t = 1;
6656 		if (!tp->t_rttlow || tp->t_rttlow > t)
6657 			tp->t_rttlow = t;
6658 		if (!rack->r_ctl.rc_rack_min_rtt ||
6659 		    SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
6660 			rack->r_ctl.rc_rack_min_rtt = t;
6661 			if (rack->r_ctl.rc_rack_min_rtt == 0) {
6662 				rack->r_ctl.rc_rack_min_rtt = 1;
6663 			}
6664 		}
6665 		us_rtt = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time) - rsm->usec_orig_send;
6666 		if (us_rtt == 0)
6667 			us_rtt = 1;
6668 		rack_apply_updated_usrtt(rack, us_rtt, tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time));
6669 		if (ack_type == SACKED)
6670 			tcp_rack_xmit_timer(rack, t + 1, len_acked, us_rtt, 2 , rsm, rsm->r_rtr_cnt);
6671 		else {
6672 			/*
6673 			 * For cum-ack we are only confident if what
6674 			 * is being acked is included in a measurement.
6675 			 * Otherwise it could be an idle period that
6676 			 * includes Delayed-ack time.
6677 			 */
6678 			tcp_rack_xmit_timer(rack, t + 1, len_acked, us_rtt,
6679 					    (rack->app_limited_needs_set ? 0 : 1), rsm, rsm->r_rtr_cnt);
6680 		}
6681 		if ((rsm->r_flags & RACK_TLP) &&
6682 		    (!IN_RECOVERY(tp->t_flags))) {
6683 			/* Segment was a TLP and our retrans matched */
6684 			if (rack->r_ctl.rc_tlp_cwnd_reduce) {
6685 				rack->r_ctl.rc_rsm_start = tp->snd_max;
6686 				rack->r_ctl.rc_cwnd_at = tp->snd_cwnd;
6687 				rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh;
6688 				rack_cong_signal(tp, NULL, CC_NDUPACK);
6689 				/*
6690 				 * When we enter recovery we need to assure
6691 				 * we send one packet.
6692 				 */
6693 				if (rack->rack_no_prr == 0) {
6694 					rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
6695 					rack_log_to_prr(rack, 7, 0);
6696 				}
6697 			}
6698 		}
6699 		if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time, rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)])) {
6700 			/* New more recent rack_tmit_time */
6701 			rack->r_ctl.rc_rack_tmit_time = rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
6702 			rack->rc_rack_rtt = t;
6703 		}
6704 		return (1);
6705 	}
6706 	/*
6707 	 * We clear the soft/rxtshift since we got an ack.
6708 	 * There is no assurance we will call the commit() function
6709 	 * so we need to clear these to avoid incorrect handling.
6710 	 */
6711 	tp->t_rxtshift = 0;
6712 	tp->t_softerror = 0;
6713 	if ((to->to_flags & TOF_TS) &&
6714 	    (ack_type == CUM_ACKED) &&
6715 	    (to->to_tsecr) &&
6716 	    ((rsm->r_flags & RACK_OVERMAX) == 0)) {
6717 		/*
6718 		 * Now which timestamp does it match? In this block the ACK
6719 		 * must be coming from a previous transmission.
6720 		 */
6721 		for (i = 0; i < rsm->r_rtr_cnt; i++) {
6722 			if (rsm->r_tim_lastsent[i] == to->to_tsecr) {
6723 				t = cts - rsm->r_tim_lastsent[i];
6724 				if ((int)t <= 0)
6725 					t = 1;
6726 				if ((i + 1) < rsm->r_rtr_cnt) {
6727 					/* Likely */
6728 					rack_earlier_retran(tp, rsm, t, cts);
6729 				}
6730 				if (!tp->t_rttlow || tp->t_rttlow > t)
6731 					tp->t_rttlow = t;
6732 				if (!rack->r_ctl.rc_rack_min_rtt || SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
6733 					rack->r_ctl.rc_rack_min_rtt = t;
6734 					if (rack->r_ctl.rc_rack_min_rtt == 0) {
6735 						rack->r_ctl.rc_rack_min_rtt = 1;
6736 					}
6737 				}
6738 				if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time,
6739 				    rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)])) {
6740 					/* New more recent rack_tmit_time */
6741 					rack->r_ctl.rc_rack_tmit_time = rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
6742 					rack->rc_rack_rtt = t;
6743 				}
6744 				tcp_rack_xmit_timer(rack, t + 1, len_acked, (t * HPTS_USEC_IN_MSEC), 0, rsm,
6745 						    rsm->r_rtr_cnt);
6746 				return (1);
6747 			}
6748 		}
6749 		goto ts_not_found;
6750 	} else {
6751 		/*
6752 		 * Ok its a SACK block that we retransmitted. or a windows
6753 		 * machine without timestamps. We can tell nothing from the
6754 		 * time-stamp since its not there or the time the peer last
6755 		 * recieved a segment that moved forward its cum-ack point.
6756 		 */
6757 ts_not_found:
6758 		i = rsm->r_rtr_cnt - 1;
6759 		t = cts - rsm->r_tim_lastsent[i];
6760 		if ((int)t <= 0)
6761 			t = 1;
6762 		if (rack->r_ctl.rc_rack_min_rtt && SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
6763 			/*
6764 			 * We retransmitted and the ack came back in less
6765 			 * than the smallest rtt we have observed. We most
6766 			 * likey did an improper retransmit as outlined in
6767 			 * 4.2 Step 3 point 2 in the rack-draft.
6768 			 */
6769 			i = rsm->r_rtr_cnt - 2;
6770 			t = cts - rsm->r_tim_lastsent[i];
6771 			rack_earlier_retran(tp, rsm, t, cts);
6772 		} else if (rack->r_ctl.rc_rack_min_rtt) {
6773 			/*
6774 			 * We retransmitted it and the retransmit did the
6775 			 * job.
6776 			 */
6777 			if (!rack->r_ctl.rc_rack_min_rtt ||
6778 			    SEQ_LT(t, rack->r_ctl.rc_rack_min_rtt)) {
6779 				rack->r_ctl.rc_rack_min_rtt = t;
6780 				if (rack->r_ctl.rc_rack_min_rtt == 0) {
6781 					rack->r_ctl.rc_rack_min_rtt = 1;
6782 				}
6783 			}
6784 			if (SEQ_LT(rack->r_ctl.rc_rack_tmit_time, rsm->r_tim_lastsent[i])) {
6785 				/* New more recent rack_tmit_time */
6786 				rack->r_ctl.rc_rack_tmit_time = rsm->r_tim_lastsent[i];
6787 				rack->rc_rack_rtt = t;
6788 			}
6789 			return (1);
6790 		}
6791 	}
6792 	return (0);
6793 }
6794 
6795 /*
6796  * Mark the SACK_PASSED flag on all entries prior to rsm send wise.
6797  */
6798 static void
6799 rack_log_sack_passed(struct tcpcb *tp,
6800     struct tcp_rack *rack, struct rack_sendmap *rsm)
6801 {
6802 	struct rack_sendmap *nrsm;
6803 
6804 	nrsm = rsm;
6805 	TAILQ_FOREACH_REVERSE_FROM(nrsm, &rack->r_ctl.rc_tmap,
6806 	    rack_head, r_tnext) {
6807 		if (nrsm == rsm) {
6808 			/* Skip orginal segment he is acked */
6809 			continue;
6810 		}
6811 		if (nrsm->r_flags & RACK_ACKED) {
6812 			/*
6813 			 * Skip ack'd segments, though we
6814 			 * should not see these, since tmap
6815 			 * should not have ack'd segments.
6816 			 */
6817 			continue;
6818 		}
6819 		if (nrsm->r_flags & RACK_SACK_PASSED) {
6820 			/*
6821 			 * We found one that is already marked
6822 			 * passed, we have been here before and
6823 			 * so all others below this are marked.
6824 			 */
6825 			break;
6826 		}
6827 		nrsm->r_flags |= RACK_SACK_PASSED;
6828 		nrsm->r_flags &= ~RACK_WAS_SACKPASS;
6829 	}
6830 }
6831 
6832 static void
6833 rack_need_set_test(struct tcpcb *tp,
6834 		   struct tcp_rack *rack,
6835 		   struct rack_sendmap *rsm,
6836 		   tcp_seq th_ack,
6837 		   int line,
6838 		   int use_which)
6839 {
6840 
6841 	if ((tp->t_flags & TF_GPUTINPROG) &&
6842 	    SEQ_GEQ(rsm->r_end, tp->gput_seq)) {
6843 		/*
6844 		 * We were app limited, and this ack
6845 		 * butts up or goes beyond the point where we want
6846 		 * to start our next measurement. We need
6847 		 * to record the new gput_ts as here and
6848 		 * possibly update the start sequence.
6849 		 */
6850 		uint32_t seq, ts;
6851 
6852 		if (rsm->r_rtr_cnt > 1) {
6853 			/*
6854 			 * This is a retransmit, can we
6855 			 * really make any assessment at this
6856 			 * point?  We are not really sure of
6857 			 * the timestamp, is it this or the
6858 			 * previous transmission?
6859 			 *
6860 			 * Lets wait for something better that
6861 			 * is not retransmitted.
6862 			 */
6863 			return;
6864 		}
6865 		seq = tp->gput_seq;
6866 		ts = tp->gput_ts;
6867 		rack->app_limited_needs_set = 0;
6868 		tp->gput_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
6869 		/* Do we start at a new end? */
6870 		if ((use_which == RACK_USE_BEG) &&
6871 		    SEQ_GEQ(rsm->r_start, tp->gput_seq)) {
6872 			/*
6873 			 * When we get an ACK that just eats
6874 			 * up some of the rsm, we set RACK_USE_BEG
6875 			 * since whats at r_start (i.e. th_ack)
6876 			 * is left unacked and thats where the
6877 			 * measurement not starts.
6878 			 */
6879 			tp->gput_seq = rsm->r_start;
6880 			rack->r_ctl.rc_gp_output_ts = rsm->usec_orig_send;
6881 		}
6882 		if ((use_which == RACK_USE_END) &&
6883 		    SEQ_GEQ(rsm->r_end, tp->gput_seq)) {
6884 			    /*
6885 			     * We use the end when the cumack
6886 			     * is moving forward and completely
6887 			     * deleting the rsm passed so basically
6888 			     * r_end holds th_ack.
6889 			     *
6890 			     * For SACK's we also want to use the end
6891 			     * since this piece just got sacked and
6892 			     * we want to target anything after that
6893 			     * in our measurement.
6894 			     */
6895 			    tp->gput_seq = rsm->r_end;
6896 			    rack->r_ctl.rc_gp_output_ts = rsm->usec_orig_send;
6897 		}
6898 		if (use_which == RACK_USE_END_OR_THACK) {
6899 			/*
6900 			 * special case for ack moving forward,
6901 			 * not a sack, we need to move all the
6902 			 * way up to where this ack cum-ack moves
6903 			 * to.
6904 			 */
6905 			if (SEQ_GT(th_ack, rsm->r_end))
6906 				tp->gput_seq = th_ack;
6907 			else
6908 				tp->gput_seq = rsm->r_end;
6909 			rack->r_ctl.rc_gp_output_ts = rsm->usec_orig_send;
6910 		}
6911 		if (SEQ_GT(tp->gput_seq, tp->gput_ack)) {
6912 			/*
6913 			 * We moved beyond this guy's range, re-calculate
6914 			 * the new end point.
6915 			 */
6916 			if (rack->rc_gp_filled == 0) {
6917 				tp->gput_ack = tp->gput_seq + max(rc_init_window(rack), (MIN_GP_WIN * ctf_fixed_maxseg(tp)));
6918 			} else {
6919 				tp->gput_ack = tp->gput_seq + rack_get_measure_window(tp, rack);
6920 			}
6921 		}
6922 		/*
6923 		 * We are moving the goal post, we may be able to clear the
6924 		 * measure_saw_probe_rtt flag.
6925 		 */
6926 		if ((rack->in_probe_rtt == 0) &&
6927 		    (rack->measure_saw_probe_rtt) &&
6928 		    (SEQ_GEQ(tp->gput_seq, rack->r_ctl.rc_probertt_sndmax_atexit)))
6929 			rack->measure_saw_probe_rtt = 0;
6930 		rack_log_pacing_delay_calc(rack, ts, tp->gput_ts,
6931 					   seq, tp->gput_seq, 0, 5, line, NULL);
6932 		if (rack->rc_gp_filled &&
6933 		    ((tp->gput_ack - tp->gput_seq) <
6934 		     max(rc_init_window(rack), (MIN_GP_WIN *
6935 						ctf_fixed_maxseg(tp))))) {
6936 			/*
6937 			 * There is no sense of continuing this measurement
6938 			 * because its too small to gain us anything we
6939 			 * trust. Skip it and that way we can start a new
6940 			 * measurement quicker.
6941 			 */
6942 			rack_log_pacing_delay_calc(rack, tp->gput_ack, tp->gput_seq,
6943 						   0, 0, 0, 6, __LINE__, NULL);
6944 			tp->t_flags &= ~TF_GPUTINPROG;
6945 		}
6946 	}
6947 }
6948 
6949 static uint32_t
6950 rack_proc_sack_blk(struct tcpcb *tp, struct tcp_rack *rack, struct sackblk *sack,
6951 		   struct tcpopt *to, struct rack_sendmap **prsm, uint32_t cts, int *moved_two)
6952 {
6953 	uint32_t start, end, changed = 0;
6954 	struct rack_sendmap stack_map;
6955 	struct rack_sendmap *rsm, *nrsm, fe, *insret, *prev, *next;
6956 	int32_t used_ref = 1;
6957 	int moved = 0;
6958 
6959 	start = sack->start;
6960 	end = sack->end;
6961 	rsm = *prsm;
6962 	memset(&fe, 0, sizeof(fe));
6963 do_rest_ofb:
6964 	if ((rsm == NULL) ||
6965 	    (SEQ_LT(end, rsm->r_start)) ||
6966 	    (SEQ_GEQ(start, rsm->r_end)) ||
6967 	    (SEQ_LT(start, rsm->r_start))) {
6968 		/*
6969 		 * We are not in the right spot,
6970 		 * find the correct spot in the tree.
6971 		 */
6972 		used_ref = 0;
6973 		fe.r_start = start;
6974 		rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
6975 		moved++;
6976 	}
6977 	if (rsm == NULL) {
6978 		/* TSNH */
6979 		goto out;
6980 	}
6981 	/* Ok we have an ACK for some piece of this rsm */
6982 	if (rsm->r_start != start) {
6983 		if ((rsm->r_flags & RACK_ACKED) == 0) {
6984 			/**
6985 			 * Need to split this in two pieces the before and after,
6986 			 * the before remains in the map, the after must be
6987 			 * added. In other words we have:
6988 			 * rsm        |--------------|
6989 			 * sackblk        |------->
6990 			 * rsm will become
6991 			 *     rsm    |---|
6992 			 * and nrsm will be  the sacked piece
6993 			 *     nrsm       |----------|
6994 			 *
6995 			 * But before we start down that path lets
6996 			 * see if the sack spans over on top of
6997 			 * the next guy and it is already sacked.
6998 			 */
6999 			next = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7000 			if (next && (next->r_flags & RACK_ACKED) &&
7001 			    SEQ_GEQ(end, next->r_start)) {
7002 				/**
7003 				 * So the next one is already acked, and
7004 				 * we can thus by hookery use our stack_map
7005 				 * to reflect the piece being sacked and
7006 				 * then adjust the two tree entries moving
7007 				 * the start and ends around. So we start like:
7008 				 *  rsm     |------------|             (not-acked)
7009 				 *  next                 |-----------| (acked)
7010 				 *  sackblk        |-------->
7011 				 *  We want to end like so:
7012 				 *  rsm     |------|                   (not-acked)
7013 				 *  next           |-----------------| (acked)
7014 				 *  nrsm           |-----|
7015 				 * Where nrsm is a temporary stack piece we
7016 				 * use to update all the gizmos.
7017 				 */
7018 				/* Copy up our fudge block */
7019 				nrsm = &stack_map;
7020 				memcpy(nrsm, rsm, sizeof(struct rack_sendmap));
7021 				/* Now adjust our tree blocks */
7022 				rsm->r_end = start;
7023 				next->r_start = start;
7024 				/* Clear out the dup ack count of the remainder */
7025 				rsm->r_dupack = 0;
7026 				rsm->r_just_ret = 0;
7027 				rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
7028 				/* Now lets make sure our fudge block is right */
7029 				nrsm->r_start = start;
7030 				/* Now lets update all the stats and such */
7031 				rack_update_rtt(tp, rack, nrsm, to, cts, SACKED, 0);
7032 				if (rack->app_limited_needs_set)
7033 					rack_need_set_test(tp, rack, nrsm, tp->snd_una, __LINE__, RACK_USE_END);
7034 				changed += (nrsm->r_end - nrsm->r_start);
7035 				rack->r_ctl.rc_sacked += (nrsm->r_end - nrsm->r_start);
7036 				if (nrsm->r_flags & RACK_SACK_PASSED) {
7037 					counter_u64_add(rack_reorder_seen, 1);
7038 					rack->r_ctl.rc_reorder_ts = cts;
7039 				}
7040 				/*
7041 				 * Now we want to go up from rsm (the
7042 				 * one left un-acked) to the next one
7043 				 * in the tmap. We do this so when
7044 				 * we walk backwards we include marking
7045 				 * sack-passed on rsm (The one passed in
7046 				 * is skipped since it is generally called
7047 				 * on something sacked before removing it
7048 				 * from the tmap).
7049 				 */
7050 				if (rsm->r_in_tmap) {
7051 					nrsm = TAILQ_NEXT(rsm, r_tnext);
7052 					/*
7053 					 * Now that we have the next
7054 					 * one walk backwards from there.
7055 					 */
7056 					if (nrsm && nrsm->r_in_tmap)
7057 						rack_log_sack_passed(tp, rack, nrsm);
7058 				}
7059 				/* Now are we done? */
7060 				if (SEQ_LT(end, next->r_end) ||
7061 				    (end == next->r_end)) {
7062 					/* Done with block */
7063 					goto out;
7064 				}
7065 				counter_u64_add(rack_sack_used_next_merge, 1);
7066 				/* Postion for the next block */
7067 				start = next->r_end;
7068 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, next);
7069 				if (rsm == NULL)
7070 					goto out;
7071 			} else {
7072 				/**
7073 				 * We can't use any hookery here, so we
7074 				 * need to split the map. We enter like
7075 				 * so:
7076 				 *  rsm      |--------|
7077 				 *  sackblk       |----->
7078 				 * We will add the new block nrsm and
7079 				 * that will be the new portion, and then
7080 				 * fall through after reseting rsm. So we
7081 				 * split and look like this:
7082 				 *  rsm      |----|
7083 				 *  sackblk       |----->
7084 				 *  nrsm          |---|
7085 				 * We then fall through reseting
7086 				 * rsm to nrsm, so the next block
7087 				 * picks it up.
7088 				 */
7089 				nrsm = rack_alloc_limit(rack, RACK_LIMIT_TYPE_SPLIT);
7090 				if (nrsm == NULL) {
7091 					/*
7092 					 * failed XXXrrs what can we do but loose the sack
7093 					 * info?
7094 					 */
7095 					goto out;
7096 				}
7097 				counter_u64_add(rack_sack_splits, 1);
7098 				rack_clone_rsm(rack, nrsm, rsm, start);
7099 				rsm->r_just_ret = 0;
7100 				insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
7101 #ifdef INVARIANTS
7102 				if (insret != NULL) {
7103 					panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
7104 					      nrsm, insret, rack, rsm);
7105 				}
7106 #endif
7107 				if (rsm->r_in_tmap) {
7108 					TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
7109 					nrsm->r_in_tmap = 1;
7110 				}
7111 				rsm->r_flags &= (~RACK_HAS_FIN);
7112 				/* Position us to point to the new nrsm that starts the sack blk */
7113 				rsm = nrsm;
7114 			}
7115 		} else {
7116 			/* Already sacked this piece */
7117 			counter_u64_add(rack_sack_skipped_acked, 1);
7118 			moved++;
7119 			if (end == rsm->r_end) {
7120 				/* Done with block */
7121 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7122 				goto out;
7123 			} else if (SEQ_LT(end, rsm->r_end)) {
7124 				/* A partial sack to a already sacked block */
7125 				moved++;
7126 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7127 				goto out;
7128 			} else {
7129 				/*
7130 				 * The end goes beyond this guy
7131 				 * repostion the start to the
7132 				 * next block.
7133 				 */
7134 				start = rsm->r_end;
7135 				rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7136 				if (rsm == NULL)
7137 					goto out;
7138 			}
7139 		}
7140 	}
7141 	if (SEQ_GEQ(end, rsm->r_end)) {
7142 		/**
7143 		 * The end of this block is either beyond this guy or right
7144 		 * at this guy. I.e.:
7145 		 *  rsm ---                 |-----|
7146 		 *  end                     |-----|
7147 		 *  <or>
7148 		 *  end                     |---------|
7149 		 */
7150 		if ((rsm->r_flags & RACK_ACKED) == 0) {
7151 			rack_update_rtt(tp, rack, rsm, to, cts, SACKED, 0);
7152 			changed += (rsm->r_end - rsm->r_start);
7153 			rack->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start);
7154 			if (rsm->r_in_tmap) /* should be true */
7155 				rack_log_sack_passed(tp, rack, rsm);
7156 			/* Is Reordering occuring? */
7157 			if (rsm->r_flags & RACK_SACK_PASSED) {
7158 				rsm->r_flags &= ~RACK_SACK_PASSED;
7159 				counter_u64_add(rack_reorder_seen, 1);
7160 				rack->r_ctl.rc_reorder_ts = cts;
7161 			}
7162 			if (rack->app_limited_needs_set)
7163 				rack_need_set_test(tp, rack, rsm, tp->snd_una, __LINE__, RACK_USE_END);
7164 			rsm->r_ack_arrival = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
7165 			rsm->r_flags |= RACK_ACKED;
7166 			rsm->r_flags &= ~RACK_TLP;
7167 			if (rsm->r_in_tmap) {
7168 				TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7169 				rsm->r_in_tmap = 0;
7170 			}
7171 		} else {
7172 			counter_u64_add(rack_sack_skipped_acked, 1);
7173 			moved++;
7174 		}
7175 		if (end == rsm->r_end) {
7176 			/* This block only - done, setup for next  */
7177 			goto out;
7178 		}
7179 		/*
7180 		 * There is more not coverend by this rsm move on
7181 		 * to the next block in the RB tree.
7182 		 */
7183 		nrsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7184 		start = rsm->r_end;
7185 		rsm = nrsm;
7186 		if (rsm == NULL)
7187 			goto out;
7188 		goto do_rest_ofb;
7189 	}
7190 	/**
7191 	 * The end of this sack block is smaller than
7192 	 * our rsm i.e.:
7193 	 *  rsm ---                 |-----|
7194 	 *  end                     |--|
7195 	 */
7196 	if ((rsm->r_flags & RACK_ACKED) == 0) {
7197 		prev = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7198 		if (prev && (prev->r_flags & RACK_ACKED)) {
7199 			/**
7200 			 * Goal, we want the right remainder of rsm to shrink
7201 			 * in place and span from (rsm->r_start = end) to rsm->r_end.
7202 			 * We want to expand prev to go all the way
7203 			 * to prev->r_end <- end.
7204 			 * so in the tree we have before:
7205 			 *   prev     |--------|         (acked)
7206 			 *   rsm               |-------| (non-acked)
7207 			 *   sackblk           |-|
7208 			 * We churn it so we end up with
7209 			 *   prev     |----------|       (acked)
7210 			 *   rsm                 |-----| (non-acked)
7211 			 *   nrsm              |-| (temporary)
7212 			 */
7213 			nrsm = &stack_map;
7214 			memcpy(nrsm, rsm, sizeof(struct rack_sendmap));
7215 			prev->r_end = end;
7216 			rsm->r_start = end;
7217 			/* Now adjust nrsm (stack copy) to be
7218 			 * the one that is the small
7219 			 * piece that was "sacked".
7220 			 */
7221 			nrsm->r_end = end;
7222 			rsm->r_dupack = 0;
7223 			rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
7224 			/*
7225 			 * Now nrsm is our new little piece
7226 			 * that is acked (which was merged
7227 			 * to prev). Update the rtt and changed
7228 			 * based on that. Also check for reordering.
7229 			 */
7230 			rack_update_rtt(tp, rack, nrsm, to, cts, SACKED, 0);
7231 			if (rack->app_limited_needs_set)
7232 				rack_need_set_test(tp, rack, nrsm, tp->snd_una, __LINE__, RACK_USE_END);
7233 			changed += (nrsm->r_end - nrsm->r_start);
7234 			rack->r_ctl.rc_sacked += (nrsm->r_end - nrsm->r_start);
7235 			if (nrsm->r_flags & RACK_SACK_PASSED) {
7236 				counter_u64_add(rack_reorder_seen, 1);
7237 				rack->r_ctl.rc_reorder_ts = cts;
7238 			}
7239 			rsm = prev;
7240 			counter_u64_add(rack_sack_used_prev_merge, 1);
7241 		} else {
7242 			/**
7243 			 * This is the case where our previous
7244 			 * block is not acked either, so we must
7245 			 * split the block in two.
7246 			 */
7247 			nrsm = rack_alloc_limit(rack, RACK_LIMIT_TYPE_SPLIT);
7248 			if (nrsm == NULL) {
7249 				/* failed rrs what can we do but loose the sack info? */
7250 				goto out;
7251 			}
7252 			/**
7253 			 * In this case nrsm becomes
7254 			 * nrsm->r_start = end;
7255 			 * nrsm->r_end = rsm->r_end;
7256 			 * which is un-acked.
7257 			 * <and>
7258 			 * rsm->r_end = nrsm->r_start;
7259 			 * i.e. the remaining un-acked
7260 			 * piece is left on the left
7261 			 * hand side.
7262 			 *
7263 			 * So we start like this
7264 			 * rsm      |----------| (not acked)
7265 			 * sackblk  |---|
7266 			 * build it so we have
7267 			 * rsm      |---|         (acked)
7268 			 * nrsm         |------|  (not acked)
7269 			 */
7270 			counter_u64_add(rack_sack_splits, 1);
7271 			rack_clone_rsm(rack, nrsm, rsm, end);
7272 			rsm->r_flags &= (~RACK_HAS_FIN);
7273 			rsm->r_just_ret = 0;
7274 			insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
7275 #ifdef INVARIANTS
7276 			if (insret != NULL) {
7277 				panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
7278 				      nrsm, insret, rack, rsm);
7279 			}
7280 #endif
7281 			if (rsm->r_in_tmap) {
7282 				TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
7283 				nrsm->r_in_tmap = 1;
7284 			}
7285 			nrsm->r_dupack = 0;
7286 			rack_log_retran_reason(rack, nrsm, __LINE__, 0, 2);
7287 			rack_update_rtt(tp, rack, rsm, to, cts, SACKED, 0);
7288 			changed += (rsm->r_end - rsm->r_start);
7289 			rack->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start);
7290 			if (rsm->r_in_tmap) /* should be true */
7291 				rack_log_sack_passed(tp, rack, rsm);
7292 			/* Is Reordering occuring? */
7293 			if (rsm->r_flags & RACK_SACK_PASSED) {
7294 				rsm->r_flags &= ~RACK_SACK_PASSED;
7295 				counter_u64_add(rack_reorder_seen, 1);
7296 				rack->r_ctl.rc_reorder_ts = cts;
7297 			}
7298 			if (rack->app_limited_needs_set)
7299 				rack_need_set_test(tp, rack, rsm, tp->snd_una, __LINE__, RACK_USE_END);
7300 			rsm->r_ack_arrival = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
7301 			rsm->r_flags |= RACK_ACKED;
7302 			rsm->r_flags &= ~RACK_TLP;
7303 			if (rsm->r_in_tmap) {
7304 				TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7305 				rsm->r_in_tmap = 0;
7306 			}
7307 		}
7308 	} else if (start != end){
7309 		/*
7310 		 * The block was already acked.
7311 		 */
7312 		counter_u64_add(rack_sack_skipped_acked, 1);
7313 		moved++;
7314 	}
7315 out:
7316 	if (rsm && (rsm->r_flags & RACK_ACKED)) {
7317 		/*
7318 		 * Now can we merge where we worked
7319 		 * with either the previous or
7320 		 * next block?
7321 		 */
7322 		next = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7323 		while (next) {
7324 		    if (next->r_flags & RACK_ACKED) {
7325 			/* yep this and next can be merged */
7326 			rsm = rack_merge_rsm(rack, rsm, next);
7327 			next = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7328 		    } else
7329 			    break;
7330 		}
7331 		/* Now what about the previous? */
7332 		prev = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7333 		while (prev) {
7334 		    if (prev->r_flags & RACK_ACKED) {
7335 			/* yep the previous and this can be merged */
7336 			rsm = rack_merge_rsm(rack, prev, rsm);
7337 			prev = RB_PREV(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7338 		    } else
7339 			    break;
7340 		}
7341 	}
7342 	if (used_ref == 0) {
7343 		counter_u64_add(rack_sack_proc_all, 1);
7344 	} else {
7345 		counter_u64_add(rack_sack_proc_short, 1);
7346 	}
7347 	/* Save off the next one for quick reference. */
7348 	if (rsm)
7349 		nrsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7350 	else
7351 		nrsm = NULL;
7352 	*prsm = rack->r_ctl.rc_sacklast = nrsm;
7353 	/* Pass back the moved. */
7354 	*moved_two = moved;
7355 	return (changed);
7356 }
7357 
7358 static void inline
7359 rack_peer_reneges(struct tcp_rack *rack, struct rack_sendmap *rsm, tcp_seq th_ack)
7360 {
7361 	struct rack_sendmap *tmap;
7362 
7363 	tmap = NULL;
7364 	while (rsm && (rsm->r_flags & RACK_ACKED)) {
7365 		/* Its no longer sacked, mark it so */
7366 		rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
7367 #ifdef INVARIANTS
7368 		if (rsm->r_in_tmap) {
7369 			panic("rack:%p rsm:%p flags:0x%x in tmap?",
7370 			      rack, rsm, rsm->r_flags);
7371 		}
7372 #endif
7373 		rsm->r_flags &= ~(RACK_ACKED|RACK_SACK_PASSED|RACK_WAS_SACKPASS);
7374 		/* Rebuild it into our tmap */
7375 		if (tmap == NULL) {
7376 			TAILQ_INSERT_HEAD(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7377 			tmap = rsm;
7378 		} else {
7379 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, tmap, rsm, r_tnext);
7380 			tmap = rsm;
7381 		}
7382 		tmap->r_in_tmap = 1;
7383 		rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7384 	}
7385 	/*
7386 	 * Now lets possibly clear the sack filter so we start
7387 	 * recognizing sacks that cover this area.
7388 	 */
7389 	sack_filter_clear(&rack->r_ctl.rack_sf, th_ack);
7390 
7391 }
7392 
7393 static void
7394 rack_do_decay(struct tcp_rack *rack)
7395 {
7396 	struct timeval res;
7397 
7398 #define	timersub(tvp, uvp, vvp)						\
7399 	do {								\
7400 		(vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec;		\
7401 		(vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec;	\
7402 		if ((vvp)->tv_usec < 0) {				\
7403 			(vvp)->tv_sec--;				\
7404 			(vvp)->tv_usec += 1000000;			\
7405 		}							\
7406 	} while (0)
7407 
7408 	timersub(&rack->r_ctl.act_rcv_time, &rack->r_ctl.rc_last_time_decay, &res);
7409 #undef timersub
7410 
7411 	rack->r_ctl.input_pkt++;
7412 	if ((rack->rc_in_persist) ||
7413 	    (res.tv_sec >= 1) ||
7414 	    (rack->rc_tp->snd_max == rack->rc_tp->snd_una)) {
7415 		/*
7416 		 * Check for decay of non-SAD,
7417 		 * we want all SAD detection metrics to
7418 		 * decay 1/4 per second (or more) passed.
7419 		 */
7420 		uint32_t pkt_delta;
7421 
7422 		pkt_delta = rack->r_ctl.input_pkt - rack->r_ctl.saved_input_pkt;
7423 		/* Update our saved tracking values */
7424 		rack->r_ctl.saved_input_pkt = rack->r_ctl.input_pkt;
7425 		rack->r_ctl.rc_last_time_decay = rack->r_ctl.act_rcv_time;
7426 		/* Now do we escape without decay? */
7427 #ifdef NETFLIX_EXP_DETECTION
7428 		if (rack->rc_in_persist ||
7429 		    (rack->rc_tp->snd_max == rack->rc_tp->snd_una) ||
7430 		    (pkt_delta < tcp_sad_low_pps)){
7431 			/*
7432 			 * We don't decay idle connections
7433 			 * or ones that have a low input pps.
7434 			 */
7435 			return;
7436 		}
7437 		/* Decay the counters */
7438 		rack->r_ctl.ack_count = ctf_decay_count(rack->r_ctl.ack_count,
7439 							tcp_sad_decay_val);
7440 		rack->r_ctl.sack_count = ctf_decay_count(rack->r_ctl.sack_count,
7441 							 tcp_sad_decay_val);
7442 		rack->r_ctl.sack_moved_extra = ctf_decay_count(rack->r_ctl.sack_moved_extra,
7443 							       tcp_sad_decay_val);
7444 		rack->r_ctl.sack_noextra_move = ctf_decay_count(rack->r_ctl.sack_noextra_move,
7445 								tcp_sad_decay_val);
7446 #endif
7447 	}
7448 }
7449 
7450 static void
7451 rack_log_ack(struct tcpcb *tp, struct tcpopt *to, struct tcphdr *th)
7452 {
7453 	uint32_t changed, entered_recovery = 0;
7454 	struct tcp_rack *rack;
7455 	struct rack_sendmap *rsm, *rm;
7456 	struct sackblk sack, sack_blocks[TCP_MAX_SACK + 1];
7457 	register uint32_t th_ack;
7458 	int32_t i, j, k, num_sack_blks = 0;
7459 	uint32_t cts, acked, ack_point, sack_changed = 0;
7460 	int loop_start = 0, moved_two = 0;
7461 	uint32_t tsused;
7462 
7463 	INP_WLOCK_ASSERT(tp->t_inpcb);
7464 	if (th->th_flags & TH_RST) {
7465 		/* We don't log resets */
7466 		return;
7467 	}
7468 	rack = (struct tcp_rack *)tp->t_fb_ptr;
7469 	cts = tcp_ts_getticks();
7470 	rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
7471 	changed = 0;
7472 	th_ack = th->th_ack;
7473 	if (rack->sack_attack_disable == 0)
7474 		rack_do_decay(rack);
7475 	if (BYTES_THIS_ACK(tp, th) >= ctf_fixed_maxseg(rack->rc_tp)) {
7476 		/*
7477 		 * You only get credit for
7478 		 * MSS and greater (and you get extra
7479 		 * credit for larger cum-ack moves).
7480 		 */
7481 		int ac;
7482 
7483 		ac = BYTES_THIS_ACK(tp, th) / ctf_fixed_maxseg(rack->rc_tp);
7484 		rack->r_ctl.ack_count += ac;
7485 		counter_u64_add(rack_ack_total, ac);
7486 	}
7487 	if (rack->r_ctl.ack_count > 0xfff00000) {
7488 		/*
7489 		 * reduce the number to keep us under
7490 		 * a uint32_t.
7491 		 */
7492 		rack->r_ctl.ack_count /= 2;
7493 		rack->r_ctl.sack_count /= 2;
7494 	}
7495 	if (SEQ_GT(th_ack, tp->snd_una)) {
7496 		rack_log_progress_event(rack, tp, ticks, PROGRESS_UPDATE, __LINE__);
7497 		tp->t_acktime = ticks;
7498 	}
7499 	if (rsm && SEQ_GT(th_ack, rsm->r_start))
7500 		changed = th_ack - rsm->r_start;
7501 	if (changed) {
7502 		/*
7503 		 * The ACK point is advancing to th_ack, we must drop off
7504 		 * the packets in the rack log and calculate any eligble
7505 		 * RTT's.
7506 		 */
7507 		rack->r_wanted_output = 1;
7508 more:
7509 		rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
7510 		if (rsm == NULL) {
7511 			if ((th_ack - 1) == tp->iss) {
7512 				/*
7513 				 * For the SYN incoming case we will not
7514 				 * have called tcp_output for the sending of
7515 				 * the SYN, so there will be no map. All
7516 				 * other cases should probably be a panic.
7517 				 */
7518 				goto proc_sack;
7519 			}
7520 			if (tp->t_flags & TF_SENTFIN) {
7521 				/* if we send a FIN we will not hav a map */
7522 				goto proc_sack;
7523 			}
7524 #ifdef INVARIANTS
7525 			panic("No rack map tp:%p for th:%p state:%d rack:%p snd_una:%u snd_max:%u snd_nxt:%u chg:%d\n",
7526 			      tp,
7527 			      th, tp->t_state, rack,
7528 			      tp->snd_una, tp->snd_max, tp->snd_nxt, changed);
7529 #endif
7530 			goto proc_sack;
7531 		}
7532 		if (SEQ_LT(th_ack, rsm->r_start)) {
7533 			/* Huh map is missing this */
7534 #ifdef INVARIANTS
7535 			printf("Rack map starts at r_start:%u for th_ack:%u huh? ts:%d rs:%d\n",
7536 			       rsm->r_start,
7537 			       th_ack, tp->t_state, rack->r_state);
7538 #endif
7539 			goto proc_sack;
7540 		}
7541 		rack_update_rtt(tp, rack, rsm, to, cts, CUM_ACKED, th_ack);
7542 		/* Now do we consume the whole thing? */
7543 		if (SEQ_GEQ(th_ack, rsm->r_end)) {
7544 			/* Its all consumed. */
7545 			uint32_t left;
7546 			uint8_t newly_acked;
7547 
7548 			rack->r_ctl.rc_holes_rxt -= rsm->r_rtr_bytes;
7549 			rsm->r_rtr_bytes = 0;
7550 			/* Record the time of highest cumack sent */
7551 			rack->r_ctl.rc_gp_cumack_ts = rsm->usec_orig_send;
7552 			rm = RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
7553 #ifdef INVARIANTS
7554 			if (rm != rsm) {
7555 				panic("removing head in rack:%p rsm:%p rm:%p",
7556 				      rack, rsm, rm);
7557 			}
7558 #endif
7559 			if (rsm->r_in_tmap) {
7560 				TAILQ_REMOVE(&rack->r_ctl.rc_tmap, rsm, r_tnext);
7561 				rsm->r_in_tmap = 0;
7562 			}
7563 			newly_acked = 1;
7564 			if (rsm->r_flags & RACK_ACKED) {
7565 				/*
7566 				 * It was acked on the scoreboard -- remove
7567 				 * it from total
7568 				 */
7569 				rack->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
7570 				newly_acked = 0;
7571 			} else if (rsm->r_flags & RACK_SACK_PASSED) {
7572 				/*
7573 				 * There are segments ACKED on the
7574 				 * scoreboard further up. We are seeing
7575 				 * reordering.
7576 				 */
7577 				rsm->r_flags &= ~RACK_SACK_PASSED;
7578 				counter_u64_add(rack_reorder_seen, 1);
7579 				rsm->r_ack_arrival = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
7580 				rsm->r_flags |= RACK_ACKED;
7581 				rack->r_ctl.rc_reorder_ts = cts;
7582 			}
7583 			left = th_ack - rsm->r_end;
7584 			if (rack->app_limited_needs_set && newly_acked)
7585 				rack_need_set_test(tp, rack, rsm, th_ack, __LINE__, RACK_USE_END_OR_THACK);
7586 			/* Free back to zone */
7587 			rack_free(rack, rsm);
7588 			if (left) {
7589 				goto more;
7590 			}
7591 			goto proc_sack;
7592 		}
7593 		if (rsm->r_flags & RACK_ACKED) {
7594 			/*
7595 			 * It was acked on the scoreboard -- remove it from
7596 			 * total for the part being cum-acked.
7597 			 */
7598 			rack->r_ctl.rc_sacked -= (th_ack - rsm->r_start);
7599 		}
7600 		/*
7601 		 * Clear the dup ack count for
7602 		 * the piece that remains.
7603 		 */
7604 		rsm->r_dupack = 0;
7605 		rack_log_retran_reason(rack, rsm, __LINE__, 0, 2);
7606 		if (rsm->r_rtr_bytes) {
7607 			/*
7608 			 * It was retransmitted adjust the
7609 			 * sack holes for what was acked.
7610 			 */
7611 			int ack_am;
7612 
7613 			ack_am = (th_ack - rsm->r_start);
7614 			if (ack_am >= rsm->r_rtr_bytes) {
7615 				rack->r_ctl.rc_holes_rxt -= ack_am;
7616 				rsm->r_rtr_bytes -= ack_am;
7617 			}
7618 		}
7619 		/*
7620 		 * Update where the piece starts and record
7621 		 * the time of send of highest cumack sent.
7622 		 */
7623 		rack->r_ctl.rc_gp_cumack_ts = rsm->usec_orig_send;
7624 		rsm->r_start = th_ack;
7625 		if (rack->app_limited_needs_set)
7626 			rack_need_set_test(tp, rack, rsm, tp->snd_una, __LINE__, RACK_USE_BEG);
7627 	}
7628 proc_sack:
7629 	/* Check for reneging */
7630 	rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
7631 	if (rsm && (rsm->r_flags & RACK_ACKED) && (th_ack == rsm->r_start)) {
7632 		/*
7633 		 * The peer has moved snd_una up to
7634 		 * the edge of this send, i.e. one
7635 		 * that it had previously acked. The only
7636 		 * way that can be true if the peer threw
7637 		 * away data (space issues) that it had
7638 		 * previously sacked (else it would have
7639 		 * given us snd_una up to (rsm->r_end).
7640 		 * We need to undo the acked markings here.
7641 		 *
7642 		 * Note we have to look to make sure th_ack is
7643 		 * our rsm->r_start in case we get an old ack
7644 		 * where th_ack is behind snd_una.
7645 		 */
7646 		rack_peer_reneges(rack, rsm, th->th_ack);
7647 	}
7648 	if ((to->to_flags & TOF_SACK) == 0) {
7649 		/* We are done nothing left */
7650 		goto out;
7651 	}
7652 	/* Sack block processing */
7653 	if (SEQ_GT(th_ack, tp->snd_una))
7654 		ack_point = th_ack;
7655 	else
7656 		ack_point = tp->snd_una;
7657 	for (i = 0; i < to->to_nsacks; i++) {
7658 		bcopy((to->to_sacks + i * TCPOLEN_SACK),
7659 		      &sack, sizeof(sack));
7660 		sack.start = ntohl(sack.start);
7661 		sack.end = ntohl(sack.end);
7662 		if (SEQ_GT(sack.end, sack.start) &&
7663 		    SEQ_GT(sack.start, ack_point) &&
7664 		    SEQ_LT(sack.start, tp->snd_max) &&
7665 		    SEQ_GT(sack.end, ack_point) &&
7666 		    SEQ_LEQ(sack.end, tp->snd_max)) {
7667 			sack_blocks[num_sack_blks] = sack;
7668 			num_sack_blks++;
7669 #ifdef NETFLIX_STATS
7670 		} else if (SEQ_LEQ(sack.start, th_ack) &&
7671 			   SEQ_LEQ(sack.end, th_ack)) {
7672 			/*
7673 			 * Its a D-SACK block.
7674 			 */
7675 			tcp_record_dsack(sack.start, sack.end);
7676 #endif
7677 		}
7678 	}
7679 	/*
7680 	 * Sort the SACK blocks so we can update the rack scoreboard with
7681 	 * just one pass.
7682 	 */
7683 	num_sack_blks = sack_filter_blks(&rack->r_ctl.rack_sf, sack_blocks,
7684 					 num_sack_blks, th->th_ack);
7685 	ctf_log_sack_filter(rack->rc_tp, num_sack_blks, sack_blocks);
7686 	if (num_sack_blks == 0)  {
7687 		/* Nothing to sack (DSACKs?) */
7688 		goto out_with_totals;
7689 	}
7690 	if (num_sack_blks < 2) {
7691 		/* Only one, we don't need to sort */
7692 		goto do_sack_work;
7693 	}
7694 	/* Sort the sacks */
7695 	for (i = 0; i < num_sack_blks; i++) {
7696 		for (j = i + 1; j < num_sack_blks; j++) {
7697 			if (SEQ_GT(sack_blocks[i].end, sack_blocks[j].end)) {
7698 				sack = sack_blocks[i];
7699 				sack_blocks[i] = sack_blocks[j];
7700 				sack_blocks[j] = sack;
7701 			}
7702 		}
7703 	}
7704 	/*
7705 	 * Now are any of the sack block ends the same (yes some
7706 	 * implementations send these)?
7707 	 */
7708 again:
7709 	if (num_sack_blks == 0)
7710 		goto out_with_totals;
7711 	if (num_sack_blks > 1) {
7712 		for (i = 0; i < num_sack_blks; i++) {
7713 			for (j = i + 1; j < num_sack_blks; j++) {
7714 				if (sack_blocks[i].end == sack_blocks[j].end) {
7715 					/*
7716 					 * Ok these two have the same end we
7717 					 * want the smallest end and then
7718 					 * throw away the larger and start
7719 					 * again.
7720 					 */
7721 					if (SEQ_LT(sack_blocks[j].start, sack_blocks[i].start)) {
7722 						/*
7723 						 * The second block covers
7724 						 * more area use that
7725 						 */
7726 						sack_blocks[i].start = sack_blocks[j].start;
7727 					}
7728 					/*
7729 					 * Now collapse out the dup-sack and
7730 					 * lower the count
7731 					 */
7732 					for (k = (j + 1); k < num_sack_blks; k++) {
7733 						sack_blocks[j].start = sack_blocks[k].start;
7734 						sack_blocks[j].end = sack_blocks[k].end;
7735 						j++;
7736 					}
7737 					num_sack_blks--;
7738 					goto again;
7739 				}
7740 			}
7741 		}
7742 	}
7743 do_sack_work:
7744 	/*
7745 	 * First lets look to see if
7746 	 * we have retransmitted and
7747 	 * can use the transmit next?
7748 	 */
7749 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
7750 	if (rsm &&
7751 	    SEQ_GT(sack_blocks[0].end, rsm->r_start) &&
7752 	    SEQ_LT(sack_blocks[0].start, rsm->r_end)) {
7753 		/*
7754 		 * We probably did the FR and the next
7755 		 * SACK in continues as we would expect.
7756 		 */
7757 		acked = rack_proc_sack_blk(tp, rack, &sack_blocks[0], to, &rsm, cts, &moved_two);
7758 		if (acked) {
7759 			rack->r_wanted_output = 1;
7760 			changed += acked;
7761 			sack_changed += acked;
7762 		}
7763 		if (num_sack_blks == 1) {
7764 			/*
7765 			 * This is what we would expect from
7766 			 * a normal implementation to happen
7767 			 * after we have retransmitted the FR,
7768 			 * i.e the sack-filter pushes down
7769 			 * to 1 block and the next to be retransmitted
7770 			 * is the sequence in the sack block (has more
7771 			 * are acked). Count this as ACK'd data to boost
7772 			 * up the chances of recovering any false positives.
7773 			 */
7774 			rack->r_ctl.ack_count += (acked / ctf_fixed_maxseg(rack->rc_tp));
7775 			counter_u64_add(rack_ack_total, (acked / ctf_fixed_maxseg(rack->rc_tp)));
7776 			counter_u64_add(rack_express_sack, 1);
7777 			if (rack->r_ctl.ack_count > 0xfff00000) {
7778 				/*
7779 				 * reduce the number to keep us under
7780 				 * a uint32_t.
7781 				 */
7782 				rack->r_ctl.ack_count /= 2;
7783 				rack->r_ctl.sack_count /= 2;
7784 			}
7785 			goto out_with_totals;
7786 		} else {
7787 			/*
7788 			 * Start the loop through the
7789 			 * rest of blocks, past the first block.
7790 			 */
7791 			moved_two = 0;
7792 			loop_start = 1;
7793 		}
7794 	}
7795 	/* Its a sack of some sort */
7796 	rack->r_ctl.sack_count++;
7797 	if (rack->r_ctl.sack_count > 0xfff00000) {
7798 		/*
7799 		 * reduce the number to keep us under
7800 		 * a uint32_t.
7801 		 */
7802 		rack->r_ctl.ack_count /= 2;
7803 		rack->r_ctl.sack_count /= 2;
7804 	}
7805 	counter_u64_add(rack_sack_total, 1);
7806 	if (rack->sack_attack_disable) {
7807 		/* An attacker disablement is in place */
7808 		if (num_sack_blks > 1) {
7809 			rack->r_ctl.sack_count += (num_sack_blks - 1);
7810 			rack->r_ctl.sack_moved_extra++;
7811 			counter_u64_add(rack_move_some, 1);
7812 			if (rack->r_ctl.sack_moved_extra > 0xfff00000) {
7813 				rack->r_ctl.sack_moved_extra /= 2;
7814 				rack->r_ctl.sack_noextra_move /= 2;
7815 			}
7816 		}
7817 		goto out;
7818 	}
7819 	rsm = rack->r_ctl.rc_sacklast;
7820 	for (i = loop_start; i < num_sack_blks; i++) {
7821 		acked = rack_proc_sack_blk(tp, rack, &sack_blocks[i], to, &rsm, cts, &moved_two);
7822 		if (acked) {
7823 			rack->r_wanted_output = 1;
7824 			changed += acked;
7825 			sack_changed += acked;
7826 		}
7827 		if (moved_two) {
7828 			/*
7829 			 * If we did not get a SACK for at least a MSS and
7830 			 * had to move at all, or if we moved more than our
7831 			 * threshold, it counts against the "extra" move.
7832 			 */
7833 			rack->r_ctl.sack_moved_extra += moved_two;
7834 			counter_u64_add(rack_move_some, 1);
7835 		} else {
7836 			/*
7837 			 * else we did not have to move
7838 			 * any more than we would expect.
7839 			 */
7840 			rack->r_ctl.sack_noextra_move++;
7841 			counter_u64_add(rack_move_none, 1);
7842 		}
7843 		if (moved_two && (acked < ctf_fixed_maxseg(rack->rc_tp))) {
7844 			/*
7845 			 * If the SACK was not a full MSS then
7846 			 * we add to sack_count the number of
7847 			 * MSS's (or possibly more than
7848 			 * a MSS if its a TSO send) we had to skip by.
7849 			 */
7850 			rack->r_ctl.sack_count += moved_two;
7851 			counter_u64_add(rack_sack_total, moved_two);
7852 		}
7853 		/*
7854 		 * Now we need to setup for the next
7855 		 * round. First we make sure we won't
7856 		 * exceed the size of our uint32_t on
7857 		 * the various counts, and then clear out
7858 		 * moved_two.
7859 		 */
7860 		if ((rack->r_ctl.sack_moved_extra > 0xfff00000) ||
7861 		    (rack->r_ctl.sack_noextra_move > 0xfff00000)) {
7862 			rack->r_ctl.sack_moved_extra /= 2;
7863 			rack->r_ctl.sack_noextra_move /= 2;
7864 		}
7865 		if (rack->r_ctl.sack_count > 0xfff00000) {
7866 			rack->r_ctl.ack_count /= 2;
7867 			rack->r_ctl.sack_count /= 2;
7868 		}
7869 		moved_two = 0;
7870 	}
7871 out_with_totals:
7872 	if (num_sack_blks > 1) {
7873 		/*
7874 		 * You get an extra stroke if
7875 		 * you have more than one sack-blk, this
7876 		 * could be where we are skipping forward
7877 		 * and the sack-filter is still working, or
7878 		 * it could be an attacker constantly
7879 		 * moving us.
7880 		 */
7881 		rack->r_ctl.sack_moved_extra++;
7882 		counter_u64_add(rack_move_some, 1);
7883 	}
7884 out:
7885 #ifdef NETFLIX_EXP_DETECTION
7886 	if ((rack->do_detection || tcp_force_detection) &&
7887 	    tcp_sack_to_ack_thresh &&
7888 	    tcp_sack_to_move_thresh &&
7889 	    ((rack->r_ctl.rc_num_maps_alloced > tcp_map_minimum) || rack->sack_attack_disable)) {
7890 		/*
7891 		 * We have thresholds set to find
7892 		 * possible attackers and disable sack.
7893 		 * Check them.
7894 		 */
7895 		uint64_t ackratio, moveratio, movetotal;
7896 
7897 		/* Log detecting */
7898 		rack_log_sad(rack, 1);
7899 		ackratio = (uint64_t)(rack->r_ctl.sack_count);
7900 		ackratio *= (uint64_t)(1000);
7901 		if (rack->r_ctl.ack_count)
7902 			ackratio /= (uint64_t)(rack->r_ctl.ack_count);
7903 		else {
7904 			/* We really should not hit here */
7905 			ackratio = 1000;
7906 		}
7907 		if ((rack->sack_attack_disable  == 0) &&
7908 		    (ackratio > rack_highest_sack_thresh_seen))
7909 			rack_highest_sack_thresh_seen = (uint32_t)ackratio;
7910 		movetotal = rack->r_ctl.sack_moved_extra;
7911 		movetotal += rack->r_ctl.sack_noextra_move;
7912 		moveratio = rack->r_ctl.sack_moved_extra;
7913 		moveratio *= (uint64_t)1000;
7914 		if (movetotal)
7915 			moveratio /= movetotal;
7916 		else {
7917 			/* No moves, thats pretty good */
7918 			moveratio = 0;
7919 		}
7920 		if ((rack->sack_attack_disable == 0) &&
7921 		    (moveratio > rack_highest_move_thresh_seen))
7922 			rack_highest_move_thresh_seen = (uint32_t)moveratio;
7923 		if (rack->sack_attack_disable == 0) {
7924 			if ((ackratio > tcp_sack_to_ack_thresh) &&
7925 			    (moveratio > tcp_sack_to_move_thresh)) {
7926 				/* Disable sack processing */
7927 				rack->sack_attack_disable = 1;
7928 				if (rack->r_rep_attack == 0) {
7929 					rack->r_rep_attack = 1;
7930 					counter_u64_add(rack_sack_attacks_detected, 1);
7931 				}
7932 				if (tcp_attack_on_turns_on_logging) {
7933 					/*
7934 					 * Turn on logging, used for debugging
7935 					 * false positives.
7936 					 */
7937 					rack->rc_tp->t_logstate = tcp_attack_on_turns_on_logging;
7938 				}
7939 				/* Clamp the cwnd at flight size */
7940 				rack->r_ctl.rc_saved_cwnd = rack->rc_tp->snd_cwnd;
7941 				rack->rc_tp->snd_cwnd = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
7942 				rack_log_sad(rack, 2);
7943 			}
7944 		} else {
7945 			/* We are sack-disabled check for false positives */
7946 			if ((ackratio <= tcp_restoral_thresh) ||
7947 			    (rack->r_ctl.rc_num_maps_alloced  < tcp_map_minimum)) {
7948 				rack->sack_attack_disable  = 0;
7949 				rack_log_sad(rack, 3);
7950 				/* Restart counting */
7951 				rack->r_ctl.sack_count = 0;
7952 				rack->r_ctl.sack_moved_extra = 0;
7953 				rack->r_ctl.sack_noextra_move = 1;
7954 				rack->r_ctl.ack_count = max(1,
7955 				      (BYTES_THIS_ACK(tp, th)/ctf_fixed_maxseg(rack->rc_tp)));
7956 
7957 				if (rack->r_rep_reverse == 0) {
7958 					rack->r_rep_reverse = 1;
7959 					counter_u64_add(rack_sack_attacks_reversed, 1);
7960 				}
7961 				/* Restore the cwnd */
7962 				if (rack->r_ctl.rc_saved_cwnd > rack->rc_tp->snd_cwnd)
7963 					rack->rc_tp->snd_cwnd = rack->r_ctl.rc_saved_cwnd;
7964 			}
7965 		}
7966 	}
7967 #endif
7968 	if (changed) {
7969 		/* Something changed cancel the rack timer */
7970 		rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
7971 	}
7972 	tsused = tcp_ts_getticks();
7973 	rsm = tcp_rack_output(tp, rack, tsused);
7974 	if ((!IN_RECOVERY(tp->t_flags)) &&
7975 	    rsm) {
7976 		/* Enter recovery */
7977 		rack->r_ctl.rc_rsm_start = rsm->r_start;
7978 		rack->r_ctl.rc_cwnd_at = tp->snd_cwnd;
7979 		rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh;
7980 		entered_recovery = 1;
7981 		rack_cong_signal(tp, NULL, CC_NDUPACK);
7982 		/*
7983 		 * When we enter recovery we need to assure we send
7984 		 * one packet.
7985 		 */
7986 		if (rack->rack_no_prr == 0) {
7987 			rack->r_ctl.rc_prr_sndcnt = ctf_fixed_maxseg(tp);
7988 			rack_log_to_prr(rack, 8, 0);
7989 		}
7990 		rack->r_timer_override = 1;
7991 		rack->r_early = 0;
7992 		rack->r_ctl.rc_agg_early = 0;
7993 	} else if (IN_RECOVERY(tp->t_flags) &&
7994 		   rsm &&
7995  		   (rack->r_rr_config == 3)) {
7996 		/*
7997 		 * Assure we can output and we get no
7998 		 * remembered pace time except the retransmit.
7999 		 */
8000 		rack->r_timer_override = 1;
8001 		rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
8002 		rack->r_ctl.rc_resend = rsm;
8003 	}
8004 	if (IN_RECOVERY(tp->t_flags) &&
8005 	    (rack->rack_no_prr == 0) &&
8006 	    (entered_recovery == 0)) {
8007 		/* Deal with PRR here (in recovery only) */
8008 		uint32_t pipe, snd_una;
8009 
8010 		rack->r_ctl.rc_prr_delivered += changed;
8011 		/* Compute prr_sndcnt */
8012 		if (SEQ_GT(tp->snd_una, th_ack)) {
8013 			snd_una = tp->snd_una;
8014 		} else {
8015 			snd_una = th_ack;
8016 		}
8017 		pipe = ((tp->snd_max - snd_una) - rack->r_ctl.rc_sacked) + rack->r_ctl.rc_holes_rxt;
8018 		if (pipe > tp->snd_ssthresh) {
8019 			long sndcnt;
8020 
8021 			sndcnt = rack->r_ctl.rc_prr_delivered * tp->snd_ssthresh;
8022 			if (rack->r_ctl.rc_prr_recovery_fs > 0)
8023 				sndcnt /= (long)rack->r_ctl.rc_prr_recovery_fs;
8024 			else {
8025 				rack->r_ctl.rc_prr_sndcnt = 0;
8026 				rack_log_to_prr(rack, 9, 0);
8027 				sndcnt = 0;
8028 			}
8029 			sndcnt++;
8030 			if (sndcnt > (long)rack->r_ctl.rc_prr_out)
8031 				sndcnt -= rack->r_ctl.rc_prr_out;
8032 			else
8033 				sndcnt = 0;
8034 			rack->r_ctl.rc_prr_sndcnt = sndcnt;
8035 			rack_log_to_prr(rack, 10, 0);
8036 		} else {
8037 			uint32_t limit;
8038 
8039 			if (rack->r_ctl.rc_prr_delivered > rack->r_ctl.rc_prr_out)
8040 				limit = (rack->r_ctl.rc_prr_delivered - rack->r_ctl.rc_prr_out);
8041 			else
8042 				limit = 0;
8043 			if (changed > limit)
8044 				limit = changed;
8045 			limit += ctf_fixed_maxseg(tp);
8046 			if (tp->snd_ssthresh > pipe) {
8047 				rack->r_ctl.rc_prr_sndcnt = min((tp->snd_ssthresh - pipe), limit);
8048 				rack_log_to_prr(rack, 11, 0);
8049 			} else {
8050 				rack->r_ctl.rc_prr_sndcnt = min(0, limit);
8051 				rack_log_to_prr(rack, 12, 0);
8052 			}
8053 		}
8054 		if ((rsm && (rack->r_ctl.rc_prr_sndcnt >= ctf_fixed_maxseg(tp)) &&
8055 		     ((rack->rc_inp->inp_in_hpts == 0) &&
8056 		      ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0)))) {
8057 			/*
8058 			 * If you are pacing output you don't want
8059 			 * to override.
8060 			 */
8061 			rack->r_early = 0;
8062 			rack->r_ctl.rc_agg_early = 0;
8063 			rack->r_timer_override = 1;
8064 		}
8065 	}
8066 }
8067 
8068 static void
8069 rack_strike_dupack(struct tcp_rack *rack)
8070 {
8071 	struct rack_sendmap *rsm;
8072 
8073 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
8074 	if (rsm && (rsm->r_dupack < 0xff)) {
8075 		rsm->r_dupack++;
8076 		if (rsm->r_dupack >= DUP_ACK_THRESHOLD) {
8077 			rack->r_wanted_output = 1;
8078 			rack->r_timer_override = 1;
8079 			rack_log_retran_reason(rack, rsm, __LINE__, 1, 3);
8080 		} else {
8081 			rack_log_retran_reason(rack, rsm, __LINE__, 0, 3);
8082 		}
8083 	}
8084 }
8085 
8086 static void
8087 rack_check_bottom_drag(struct tcpcb *tp,
8088 		       struct tcp_rack *rack,
8089 		       struct socket *so, int32_t acked)
8090 {
8091 	uint32_t segsiz, minseg;
8092 
8093 	segsiz = ctf_fixed_maxseg(tp);
8094 	minseg = segsiz;
8095 
8096 	if (tp->snd_max == tp->snd_una) {
8097 		/*
8098 		 * We are doing dynamic pacing and we are way
8099 		 * under. Basically everything got acked while
8100 		 * we were still waiting on the pacer to expire.
8101 		 *
8102 		 * This means we need to boost the b/w in
8103 		 * addition to any earlier boosting of
8104 		 * the multipler.
8105 		 */
8106 		rack->rc_dragged_bottom = 1;
8107 		rack_validate_multipliers_at_or_above100(rack);
8108 		/*
8109 		 * Lets use the segment bytes acked plus
8110 		 * the lowest RTT seen as the basis to
8111 		 * form a b/w estimate. This will be off
8112 		 * due to the fact that the true estimate
8113 		 * should be around 1/2 the time of the RTT
8114 		 * but we can settle for that.
8115 		 */
8116 		if ((rack->r_ctl.rack_rs.rs_flags & RACK_RTT_VALID) &&
8117 		    acked) {
8118 			uint64_t bw, calc_bw, rtt;
8119 
8120 			rtt = rack->r_ctl.rack_rs.rs_us_rtt;
8121 			bw = acked;
8122 			calc_bw = bw * 1000000;
8123 			calc_bw /= rtt;
8124 			if (rack->r_ctl.last_max_bw &&
8125 			    (rack->r_ctl.last_max_bw < calc_bw)) {
8126 				/*
8127 				 * If we have a last calculated max bw
8128 				 * enforce it.
8129 				 */
8130 				calc_bw = rack->r_ctl.last_max_bw;
8131 			}
8132 			/* now plop it in */
8133 			if (rack->rc_gp_filled == 0) {
8134 				if (calc_bw > ONE_POINT_TWO_MEG) {
8135 					/*
8136 					 * If we have no measurement
8137 					 * don't let us set in more than
8138 					 * 1.2Mbps. If we are still too
8139 					 * low after pacing with this we
8140 					 * will hopefully have a max b/w
8141 					 * available to sanity check things.
8142 					 */
8143 					calc_bw = ONE_POINT_TWO_MEG;
8144 				}
8145 				rack->r_ctl.rc_rtt_diff = 0;
8146 				rack->r_ctl.gp_bw = calc_bw;
8147 				rack->rc_gp_filled = 1;
8148 				rack->r_ctl.num_avg = RACK_REQ_AVG;
8149 				rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
8150 			} else if (calc_bw > rack->r_ctl.gp_bw) {
8151 				rack->r_ctl.rc_rtt_diff = 0;
8152 				rack->r_ctl.num_avg = RACK_REQ_AVG;
8153 				rack->r_ctl.gp_bw = calc_bw;
8154 				rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
8155 			} else
8156 				rack_increase_bw_mul(rack, -1, 0, 0, 1);
8157 			/*
8158 			 * For acks over 1mss we do a extra boost to simulate
8159 			 * where we would get 2 acks (we want 110 for the mul).
8160 			 */
8161 			if (acked > segsiz)
8162 				rack_increase_bw_mul(rack, -1, 0, 0, 1);
8163 		} else {
8164 			/*
8165 			 * Huh, this should not be, settle
8166 			 * for just an old increase.
8167 			 */
8168 			rack_increase_bw_mul(rack, -1, 0, 0, 1);
8169 		}
8170 	} else if ((IN_RECOVERY(tp->t_flags) == 0) &&
8171 		   (sbavail(&so->so_snd) > max((segsiz * (4 + rack_req_segs)),
8172 					       minseg)) &&
8173 		   (rack->r_ctl.cwnd_to_use > max((segsiz * (rack_req_segs + 2)), minseg)) &&
8174 		   (tp->snd_wnd > max((segsiz * (rack_req_segs + 2)), minseg)) &&
8175 		   (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) <=
8176 		    (segsiz * rack_req_segs))) {
8177 		/*
8178 		 * We are doing dynamic GP pacing and
8179 		 * we have everything except 1MSS or less
8180 		 * bytes left out. We are still pacing away.
8181 		 * And there is data that could be sent, This
8182 		 * means we are inserting delayed ack time in
8183 		 * our measurements because we are pacing too slow.
8184 		 */
8185 		rack_validate_multipliers_at_or_above100(rack);
8186 		rack->rc_dragged_bottom = 1;
8187 		rack_increase_bw_mul(rack, -1, 0, 0, 1);
8188 	}
8189 }
8190 
8191 /*
8192  * Return value of 1, we do not need to call rack_process_data().
8193  * return value of 0, rack_process_data can be called.
8194  * For ret_val if its 0 the TCP is locked, if its non-zero
8195  * its unlocked and probably unsafe to touch the TCB.
8196  */
8197 static int
8198 rack_process_ack(struct mbuf *m, struct tcphdr *th, struct socket *so,
8199     struct tcpcb *tp, struct tcpopt *to,
8200     uint32_t tiwin, int32_t tlen,
8201     int32_t * ofia, int32_t thflags, int32_t * ret_val)
8202 {
8203 	int32_t ourfinisacked = 0;
8204 	int32_t nsegs, acked_amount;
8205 	int32_t acked;
8206 	struct mbuf *mfree;
8207 	struct tcp_rack *rack;
8208 	int32_t under_pacing = 0;
8209 	int32_t recovery = 0;
8210 
8211 	rack = (struct tcp_rack *)tp->t_fb_ptr;
8212 	if (SEQ_GT(th->th_ack, tp->snd_max)) {
8213 		ctf_do_dropafterack(m, tp, th, thflags, tlen, ret_val);
8214 		rack->r_wanted_output = 1;
8215 		return (1);
8216 	}
8217 	if (rack->rc_gp_filled &&
8218 	    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
8219 		under_pacing = 1;
8220 	}
8221 	if (SEQ_GEQ(th->th_ack, tp->snd_una) || to->to_nsacks) {
8222 		if (rack->rc_in_persist)
8223 			tp->t_rxtshift = 0;
8224 		if ((th->th_ack == tp->snd_una) && (tiwin == tp->snd_wnd))
8225 			rack_strike_dupack(rack);
8226 		rack_log_ack(tp, to, th);
8227 	}
8228 	if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
8229 		/*
8230 		 * Old ack, behind (or duplicate to) the last one rcv'd
8231 		 * Note: Should mark reordering is occuring! We should also
8232 		 * look for sack blocks arriving e.g. ack 1, 4-4 then ack 1,
8233 		 * 3-3, 4-4 would be reording. As well as ack 1, 3-3 <no
8234 		 * retran and> ack 3
8235 		 */
8236 		return (0);
8237 	}
8238 	/*
8239 	 * If we reach this point, ACK is not a duplicate, i.e., it ACKs
8240 	 * something we sent.
8241 	 */
8242 	if (tp->t_flags & TF_NEEDSYN) {
8243 		/*
8244 		 * T/TCP: Connection was half-synchronized, and our SYN has
8245 		 * been ACK'd (so connection is now fully synchronized).  Go
8246 		 * to non-starred state, increment snd_una for ACK of SYN,
8247 		 * and check if we can do window scaling.
8248 		 */
8249 		tp->t_flags &= ~TF_NEEDSYN;
8250 		tp->snd_una++;
8251 		/* Do window scaling? */
8252 		if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
8253 		    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
8254 			tp->rcv_scale = tp->request_r_scale;
8255 			/* Send window already scaled. */
8256 		}
8257 	}
8258 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
8259 	INP_WLOCK_ASSERT(tp->t_inpcb);
8260 
8261 	acked = BYTES_THIS_ACK(tp, th);
8262 	KMOD_TCPSTAT_ADD(tcps_rcvackpack, nsegs);
8263 	KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
8264 	/*
8265 	 * If we just performed our first retransmit, and the ACK arrives
8266 	 * within our recovery window, then it was a mistake to do the
8267 	 * retransmit in the first place.  Recover our original cwnd and
8268 	 * ssthresh, and proceed to transmit where we left off.
8269 	 */
8270 	if (tp->t_flags & TF_PREVVALID) {
8271 		tp->t_flags &= ~TF_PREVVALID;
8272 		if (tp->t_rxtshift == 1 &&
8273 		    (int)(ticks - tp->t_badrxtwin) < 0)
8274 			rack_cong_signal(tp, th, CC_RTO_ERR);
8275 	}
8276 	if (acked) {
8277 		/* assure we are not backed off */
8278 		tp->t_rxtshift = 0;
8279 		rack->rc_tlp_in_progress = 0;
8280 		rack->r_ctl.rc_tlp_cnt_out = 0;
8281 		/*
8282 		 * If it is the RXT timer we want to
8283 		 * stop it, so we can restart a TLP.
8284 		 */
8285 		if (rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT)
8286 			rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
8287 #ifdef NETFLIX_HTTP_LOGGING
8288 		tcp_http_check_for_comp(rack->rc_tp, th->th_ack);
8289 #endif
8290 	}
8291 	/*
8292 	 * If we have a timestamp reply, update smoothed round trip time. If
8293 	 * no timestamp is present but transmit timer is running and timed
8294 	 * sequence number was acked, update smoothed round trip time. Since
8295 	 * we now have an rtt measurement, cancel the timer backoff (cf.,
8296 	 * Phil Karn's retransmit alg.). Recompute the initial retransmit
8297 	 * timer.
8298 	 *
8299 	 * Some boxes send broken timestamp replies during the SYN+ACK
8300 	 * phase, ignore timestamps of 0 or we could calculate a huge RTT
8301 	 * and blow up the retransmit timer.
8302 	 */
8303 	/*
8304 	 * If all outstanding data is acked, stop retransmit timer and
8305 	 * remember to restart (more output or persist). If there is more
8306 	 * data to be acked, restart retransmit timer, using current
8307 	 * (possibly backed-off) value.
8308 	 */
8309 	if (acked == 0) {
8310 		if (ofia)
8311 			*ofia = ourfinisacked;
8312 		return (0);
8313 	}
8314 	if (rack->r_ctl.rc_early_recovery) {
8315 		if (IN_RECOVERY(tp->t_flags)) {
8316 			if (SEQ_LT(th->th_ack, tp->snd_recover) &&
8317 			    (SEQ_LT(th->th_ack, tp->snd_max))) {
8318 				tcp_rack_partialack(tp, th);
8319 			} else {
8320 				rack_post_recovery(tp, th);
8321 				recovery = 1;
8322 			}
8323 		}
8324 	}
8325 	/*
8326 	 * Let the congestion control algorithm update congestion control
8327 	 * related information. This typically means increasing the
8328 	 * congestion window.
8329 	 */
8330 	rack_ack_received(tp, rack, th, nsegs, CC_ACK, recovery);
8331 	SOCKBUF_LOCK(&so->so_snd);
8332 	acked_amount = min(acked, (int)sbavail(&so->so_snd));
8333 	tp->snd_wnd -= acked_amount;
8334 	mfree = sbcut_locked(&so->so_snd, acked_amount);
8335 	if ((sbused(&so->so_snd) == 0) &&
8336 	    (acked > acked_amount) &&
8337 	    (tp->t_state >= TCPS_FIN_WAIT_1) &&
8338 	    (tp->t_flags & TF_SENTFIN)) {
8339 		/*
8340 		 * We must be sure our fin
8341 		 * was sent and acked (we can be
8342 		 * in FIN_WAIT_1 without having
8343 		 * sent the fin).
8344 		 */
8345 		ourfinisacked = 1;
8346 	}
8347 	SOCKBUF_UNLOCK(&so->so_snd);
8348 	tp->t_flags |= TF_WAKESOW;
8349 	m_freem(mfree);
8350 	if (rack->r_ctl.rc_early_recovery == 0) {
8351 		if (IN_RECOVERY(tp->t_flags)) {
8352 			if (SEQ_LT(th->th_ack, tp->snd_recover) &&
8353 			    (SEQ_LT(th->th_ack, tp->snd_max))) {
8354 				tcp_rack_partialack(tp, th);
8355 			} else {
8356 				rack_post_recovery(tp, th);
8357 			}
8358 		}
8359 	}
8360 	tp->snd_una = th->th_ack;
8361 	if (SEQ_GT(tp->snd_una, tp->snd_recover))
8362 		tp->snd_recover = tp->snd_una;
8363 
8364 	if (SEQ_LT(tp->snd_nxt, tp->snd_una)) {
8365 		tp->snd_nxt = tp->snd_una;
8366 	}
8367 	if (under_pacing &&
8368 	    (rack->use_fixed_rate == 0) &&
8369 	    (rack->in_probe_rtt == 0) &&
8370 	    rack->rc_gp_dyn_mul &&
8371 	    rack->rc_always_pace) {
8372 		/* Check if we are dragging bottom */
8373 		rack_check_bottom_drag(tp, rack, so, acked);
8374 	}
8375 	if (tp->snd_una == tp->snd_max) {
8376 		/* Nothing left outstanding */
8377 		rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
8378 		if (rack->r_ctl.rc_went_idle_time == 0)
8379 			rack->r_ctl.rc_went_idle_time = 1;
8380 		rack_log_progress_event(rack, tp, 0, PROGRESS_CLEAR, __LINE__);
8381 		if (sbavail(&tp->t_inpcb->inp_socket->so_snd) == 0)
8382 			tp->t_acktime = 0;
8383 		rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
8384 		/* Set need output so persist might get set */
8385 		rack->r_wanted_output = 1;
8386 		sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
8387 		if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
8388 		    (sbavail(&so->so_snd) == 0) &&
8389 		    (tp->t_flags2 & TF2_DROP_AF_DATA)) {
8390 			/*
8391 			 * The socket was gone and the
8392 			 * peer sent data, time to
8393 			 * reset him.
8394 			 */
8395 			*ret_val = 1;
8396 			/* tcp_close will kill the inp pre-log the Reset */
8397 			tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
8398 			tp = tcp_close(tp);
8399 			ctf_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, tlen);
8400 			return (1);
8401 		}
8402 	}
8403 	if (ofia)
8404 		*ofia = ourfinisacked;
8405 	return (0);
8406 }
8407 
8408 static void
8409 rack_collapsed_window(struct tcp_rack *rack)
8410 {
8411 	/*
8412 	 * Now we must walk the
8413 	 * send map and divide the
8414 	 * ones left stranded. These
8415 	 * guys can't cause us to abort
8416 	 * the connection and are really
8417 	 * "unsent". However if a buggy
8418 	 * client actually did keep some
8419 	 * of the data i.e. collapsed the win
8420 	 * and refused to ack and then opened
8421 	 * the win and acked that data. We would
8422 	 * get into an ack war, the simplier
8423 	 * method then of just pretending we
8424 	 * did not send those segments something
8425 	 * won't work.
8426 	 */
8427 	struct rack_sendmap *rsm, *nrsm, fe, *insret;
8428 	tcp_seq max_seq;
8429 
8430 	max_seq = rack->rc_tp->snd_una + rack->rc_tp->snd_wnd;
8431 	memset(&fe, 0, sizeof(fe));
8432 	fe.r_start = max_seq;
8433 	/* Find the first seq past or at maxseq */
8434 	rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
8435 	if (rsm == NULL) {
8436 		/* Nothing to do strange */
8437 		rack->rc_has_collapsed = 0;
8438 		return;
8439 	}
8440 	/*
8441 	 * Now do we need to split at
8442 	 * the collapse point?
8443 	 */
8444 	if (SEQ_GT(max_seq, rsm->r_start)) {
8445 		nrsm = rack_alloc_limit(rack, RACK_LIMIT_TYPE_SPLIT);
8446 		if (nrsm == NULL) {
8447 			/* We can't get a rsm, mark all? */
8448 			nrsm = rsm;
8449 			goto no_split;
8450 		}
8451 		/* Clone it */
8452 		rack_clone_rsm(rack, nrsm, rsm, max_seq);
8453 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm);
8454 #ifdef INVARIANTS
8455 		if (insret != NULL) {
8456 			panic("Insert in rb tree of %p fails ret:%p rack:%p rsm:%p",
8457 			      nrsm, insret, rack, rsm);
8458 		}
8459 #endif
8460 		if (rsm->r_in_tmap) {
8461 			TAILQ_INSERT_AFTER(&rack->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
8462 			nrsm->r_in_tmap = 1;
8463 		}
8464 		/*
8465 		 * Set in the new RSM as the
8466 		 * collapsed starting point
8467 		 */
8468 		rsm = nrsm;
8469 	}
8470 no_split:
8471 	counter_u64_add(rack_collapsed_win, 1);
8472 	RB_FOREACH_FROM(nrsm, rack_rb_tree_head, rsm) {
8473 		nrsm->r_flags |= RACK_RWND_COLLAPSED;
8474 		rack->rc_has_collapsed = 1;
8475 	}
8476 }
8477 
8478 static void
8479 rack_un_collapse_window(struct tcp_rack *rack)
8480 {
8481 	struct rack_sendmap *rsm;
8482 
8483 	RB_FOREACH_REVERSE(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree) {
8484 		if (rsm->r_flags & RACK_RWND_COLLAPSED)
8485 			rsm->r_flags &= ~RACK_RWND_COLLAPSED;
8486 		else
8487 			break;
8488 	}
8489 	rack->rc_has_collapsed = 0;
8490 }
8491 
8492 static void
8493 rack_handle_delayed_ack(struct tcpcb *tp, struct tcp_rack *rack,
8494 			int32_t tlen, int32_t tfo_syn)
8495 {
8496 	if (DELAY_ACK(tp, tlen) || tfo_syn) {
8497 		if (rack->rc_dack_mode &&
8498 		    (tlen > 500) &&
8499 		    (rack->rc_dack_toggle == 1)) {
8500 			goto no_delayed_ack;
8501 		}
8502 		rack_timer_cancel(tp, rack,
8503 				  rack->r_ctl.rc_rcvtime, __LINE__);
8504 		tp->t_flags |= TF_DELACK;
8505 	} else {
8506 no_delayed_ack:
8507 		rack->r_wanted_output = 1;
8508 		tp->t_flags |= TF_ACKNOW;
8509 		if (rack->rc_dack_mode) {
8510 			if (tp->t_flags & TF_DELACK)
8511 				rack->rc_dack_toggle = 1;
8512 			else
8513 				rack->rc_dack_toggle = 0;
8514 		}
8515 	}
8516 }
8517 /*
8518  * Return value of 1, the TCB is unlocked and most
8519  * likely gone, return value of 0, the TCP is still
8520  * locked.
8521  */
8522 static int
8523 rack_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so,
8524     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
8525     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
8526 {
8527 	/*
8528 	 * Update window information. Don't look at window if no ACK: TAC's
8529 	 * send garbage on first SYN.
8530 	 */
8531 	int32_t nsegs;
8532 	int32_t tfo_syn;
8533 	struct tcp_rack *rack;
8534 
8535 	rack = (struct tcp_rack *)tp->t_fb_ptr;
8536 	INP_WLOCK_ASSERT(tp->t_inpcb);
8537 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
8538 	if ((thflags & TH_ACK) &&
8539 	    (SEQ_LT(tp->snd_wl1, th->th_seq) ||
8540 	    (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) ||
8541 	    (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) {
8542 		/* keep track of pure window updates */
8543 		if (tlen == 0 &&
8544 		    tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd)
8545 			KMOD_TCPSTAT_INC(tcps_rcvwinupd);
8546 		tp->snd_wnd = tiwin;
8547 		tp->snd_wl1 = th->th_seq;
8548 		tp->snd_wl2 = th->th_ack;
8549 		if (tp->snd_wnd > tp->max_sndwnd)
8550 			tp->max_sndwnd = tp->snd_wnd;
8551 		rack->r_wanted_output = 1;
8552 	} else if (thflags & TH_ACK) {
8553 		if ((tp->snd_wl2 == th->th_ack) && (tiwin < tp->snd_wnd)) {
8554 			tp->snd_wnd = tiwin;
8555 			tp->snd_wl1 = th->th_seq;
8556 			tp->snd_wl2 = th->th_ack;
8557 		}
8558 	}
8559 	if (tp->snd_wnd < ctf_outstanding(tp))
8560 		/* The peer collapsed the window */
8561 		rack_collapsed_window(rack);
8562 	else if (rack->rc_has_collapsed)
8563 		rack_un_collapse_window(rack);
8564 	/* Was persist timer active and now we have window space? */
8565 	if ((rack->rc_in_persist != 0) &&
8566 	    (tp->snd_wnd >= min((rack->r_ctl.rc_high_rwnd/2),
8567 				rack->r_ctl.rc_pace_min_segs))) {
8568 		rack_exit_persist(tp, rack, rack->r_ctl.rc_rcvtime);
8569 		tp->snd_nxt = tp->snd_max;
8570 		/* Make sure we output to start the timer */
8571 		rack->r_wanted_output = 1;
8572 	}
8573 	/* Do we enter persists? */
8574 	if ((rack->rc_in_persist == 0) &&
8575 	    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), rack->r_ctl.rc_pace_min_segs)) &&
8576 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
8577 	    (tp->snd_max == tp->snd_una) &&
8578 	    sbavail(&tp->t_inpcb->inp_socket->so_snd) &&
8579 	    (sbavail(&tp->t_inpcb->inp_socket->so_snd) > tp->snd_wnd)) {
8580 		/*
8581 		 * Here the rwnd is less than
8582 		 * the pacing size, we are established,
8583 		 * nothing is outstanding, and there is
8584 		 * data to send. Enter persists.
8585 		 */
8586 		tp->snd_nxt = tp->snd_una;
8587 		rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
8588 	}
8589 	if (tp->t_flags2 & TF2_DROP_AF_DATA) {
8590 		m_freem(m);
8591 		return (0);
8592 	}
8593 	/*
8594 	 * don't process the URG bit, ignore them drag
8595 	 * along the up.
8596 	 */
8597 	tp->rcv_up = tp->rcv_nxt;
8598 	INP_WLOCK_ASSERT(tp->t_inpcb);
8599 
8600 	/*
8601 	 * Process the segment text, merging it into the TCP sequencing
8602 	 * queue, and arranging for acknowledgment of receipt if necessary.
8603 	 * This process logically involves adjusting tp->rcv_wnd as data is
8604 	 * presented to the user (this happens in tcp_usrreq.c, case
8605 	 * PRU_RCVD).  If a FIN has already been received on this connection
8606 	 * then we just ignore the text.
8607 	 */
8608 	tfo_syn = ((tp->t_state == TCPS_SYN_RECEIVED) &&
8609 		   IS_FASTOPEN(tp->t_flags));
8610 	if ((tlen || (thflags & TH_FIN) || (tfo_syn && tlen > 0)) &&
8611 	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
8612 		tcp_seq save_start = th->th_seq;
8613 		tcp_seq save_rnxt  = tp->rcv_nxt;
8614 		int     save_tlen  = tlen;
8615 
8616 		m_adj(m, drop_hdrlen);	/* delayed header drop */
8617 		/*
8618 		 * Insert segment which includes th into TCP reassembly
8619 		 * queue with control block tp.  Set thflags to whether
8620 		 * reassembly now includes a segment with FIN.  This handles
8621 		 * the common case inline (segment is the next to be
8622 		 * received on an established connection, and the queue is
8623 		 * empty), avoiding linkage into and removal from the queue
8624 		 * and repetition of various conversions. Set DELACK for
8625 		 * segments received in order, but ack immediately when
8626 		 * segments are out of order (so fast retransmit can work).
8627 		 */
8628 		if (th->th_seq == tp->rcv_nxt &&
8629 		    SEGQ_EMPTY(tp) &&
8630 		    (TCPS_HAVEESTABLISHED(tp->t_state) ||
8631 		    tfo_syn)) {
8632 #ifdef NETFLIX_SB_LIMITS
8633 			u_int mcnt, appended;
8634 
8635 			if (so->so_rcv.sb_shlim) {
8636 				mcnt = m_memcnt(m);
8637 				appended = 0;
8638 				if (counter_fo_get(so->so_rcv.sb_shlim, mcnt,
8639 				    CFO_NOSLEEP, NULL) == false) {
8640 					counter_u64_add(tcp_sb_shlim_fails, 1);
8641 					m_freem(m);
8642 					return (0);
8643 				}
8644 			}
8645 #endif
8646 			rack_handle_delayed_ack(tp, rack, tlen, tfo_syn);
8647 			tp->rcv_nxt += tlen;
8648 			if (tlen &&
8649 			    ((tp->t_flags2 & TF2_FBYTES_COMPLETE) == 0) &&
8650 			    (tp->t_fbyte_in == 0)) {
8651 				tp->t_fbyte_in = ticks;
8652 				if (tp->t_fbyte_in == 0)
8653 					tp->t_fbyte_in = 1;
8654 				if (tp->t_fbyte_out && tp->t_fbyte_in)
8655 					tp->t_flags2 |= TF2_FBYTES_COMPLETE;
8656 			}
8657 			thflags = th->th_flags & TH_FIN;
8658 			KMOD_TCPSTAT_ADD(tcps_rcvpack, nsegs);
8659 			KMOD_TCPSTAT_ADD(tcps_rcvbyte, tlen);
8660 			SOCKBUF_LOCK(&so->so_rcv);
8661 			if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
8662 				m_freem(m);
8663 			} else
8664 #ifdef NETFLIX_SB_LIMITS
8665 				appended =
8666 #endif
8667 					sbappendstream_locked(&so->so_rcv, m, 0);
8668 			SOCKBUF_UNLOCK(&so->so_rcv);
8669 			tp->t_flags |= TF_WAKESOR;
8670 #ifdef NETFLIX_SB_LIMITS
8671 			if (so->so_rcv.sb_shlim && appended != mcnt)
8672 				counter_fo_release(so->so_rcv.sb_shlim,
8673 				    mcnt - appended);
8674 #endif
8675 		} else {
8676 			/*
8677 			 * XXX: Due to the header drop above "th" is
8678 			 * theoretically invalid by now.  Fortunately
8679 			 * m_adj() doesn't actually frees any mbufs when
8680 			 * trimming from the head.
8681 			 */
8682 			tcp_seq temp = save_start;
8683 			thflags = tcp_reass(tp, th, &temp, &tlen, m);
8684 			tp->t_flags |= TF_ACKNOW;
8685 		}
8686                 if ((tp->t_flags & TF_SACK_PERMIT) && (save_tlen > 0)) {
8687                         if ((tlen == 0) && (SEQ_LT(save_start, save_rnxt))) {
8688                                 /*
8689                                  * DSACK actually handled in the fastpath
8690                                  * above.
8691                                  */
8692 				RACK_OPTS_INC(tcp_sack_path_1);
8693                                 tcp_update_sack_list(tp, save_start,
8694                                     save_start + save_tlen);
8695                         } else if ((tlen > 0) && SEQ_GT(tp->rcv_nxt, save_rnxt)) {
8696                                 if ((tp->rcv_numsacks >= 1) &&
8697                                     (tp->sackblks[0].end == save_start)) {
8698                                         /*
8699                                          * Partial overlap, recorded at todrop
8700                                          * above.
8701                                          */
8702 					RACK_OPTS_INC(tcp_sack_path_2a);
8703                                         tcp_update_sack_list(tp,
8704                                             tp->sackblks[0].start,
8705                                             tp->sackblks[0].end);
8706                                 } else {
8707 					RACK_OPTS_INC(tcp_sack_path_2b);
8708                                         tcp_update_dsack_list(tp, save_start,
8709                                             save_start + save_tlen);
8710                                 }
8711                         } else if (tlen >= save_tlen) {
8712                                 /* Update of sackblks. */
8713 				RACK_OPTS_INC(tcp_sack_path_3);
8714                                 tcp_update_dsack_list(tp, save_start,
8715                                     save_start + save_tlen);
8716                         } else if (tlen > 0) {
8717 				RACK_OPTS_INC(tcp_sack_path_4);
8718                                 tcp_update_dsack_list(tp, save_start,
8719                                     save_start + tlen);
8720                         }
8721                 }
8722 	} else {
8723 		m_freem(m);
8724 		thflags &= ~TH_FIN;
8725 	}
8726 
8727 	/*
8728 	 * If FIN is received ACK the FIN and let the user know that the
8729 	 * connection is closing.
8730 	 */
8731 	if (thflags & TH_FIN) {
8732 		if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
8733 			socantrcvmore(so);
8734 			/* The socket upcall is handled by socantrcvmore. */
8735 			tp->t_flags &= ~TF_WAKESOR;
8736 			/*
8737 			 * If connection is half-synchronized (ie NEEDSYN
8738 			 * flag on) then delay ACK, so it may be piggybacked
8739 			 * when SYN is sent. Otherwise, since we received a
8740 			 * FIN then no more input can be expected, send ACK
8741 			 * now.
8742 			 */
8743 			if (tp->t_flags & TF_NEEDSYN) {
8744 				rack_timer_cancel(tp, rack,
8745 				    rack->r_ctl.rc_rcvtime, __LINE__);
8746 				tp->t_flags |= TF_DELACK;
8747 			} else {
8748 				tp->t_flags |= TF_ACKNOW;
8749 			}
8750 			tp->rcv_nxt++;
8751 		}
8752 		switch (tp->t_state) {
8753 			/*
8754 			 * In SYN_RECEIVED and ESTABLISHED STATES enter the
8755 			 * CLOSE_WAIT state.
8756 			 */
8757 		case TCPS_SYN_RECEIVED:
8758 			tp->t_starttime = ticks;
8759 			/* FALLTHROUGH */
8760 		case TCPS_ESTABLISHED:
8761 			rack_timer_cancel(tp, rack,
8762 			    rack->r_ctl.rc_rcvtime, __LINE__);
8763 			tcp_state_change(tp, TCPS_CLOSE_WAIT);
8764 			break;
8765 
8766 			/*
8767 			 * If still in FIN_WAIT_1 STATE FIN has not been
8768 			 * acked so enter the CLOSING state.
8769 			 */
8770 		case TCPS_FIN_WAIT_1:
8771 			rack_timer_cancel(tp, rack,
8772 			    rack->r_ctl.rc_rcvtime, __LINE__);
8773 			tcp_state_change(tp, TCPS_CLOSING);
8774 			break;
8775 
8776 			/*
8777 			 * In FIN_WAIT_2 state enter the TIME_WAIT state,
8778 			 * starting the time-wait timer, turning off the
8779 			 * other standard timers.
8780 			 */
8781 		case TCPS_FIN_WAIT_2:
8782 			rack_timer_cancel(tp, rack,
8783 			    rack->r_ctl.rc_rcvtime, __LINE__);
8784 			tcp_twstart(tp);
8785 			return (1);
8786 		}
8787 	}
8788 	/*
8789 	 * Return any desired output.
8790 	 */
8791 	if ((tp->t_flags & TF_ACKNOW) ||
8792 	    (sbavail(&so->so_snd) > (tp->snd_max - tp->snd_una))) {
8793 		rack->r_wanted_output = 1;
8794 	}
8795 	INP_WLOCK_ASSERT(tp->t_inpcb);
8796 	return (0);
8797 }
8798 
8799 /*
8800  * Here nothing is really faster, its just that we
8801  * have broken out the fast-data path also just like
8802  * the fast-ack.
8803  */
8804 static int
8805 rack_do_fastnewdata(struct mbuf *m, struct tcphdr *th, struct socket *so,
8806     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
8807     uint32_t tiwin, int32_t nxt_pkt, uint8_t iptos)
8808 {
8809 	int32_t nsegs;
8810 	int32_t newsize = 0;	/* automatic sockbuf scaling */
8811 	struct tcp_rack *rack;
8812 #ifdef NETFLIX_SB_LIMITS
8813 	u_int mcnt, appended;
8814 #endif
8815 #ifdef TCPDEBUG
8816 	/*
8817 	 * The size of tcp_saveipgen must be the size of the max ip header,
8818 	 * now IPv6.
8819 	 */
8820 	u_char tcp_saveipgen[IP6_HDR_LEN];
8821 	struct tcphdr tcp_savetcp;
8822 	short ostate = 0;
8823 
8824 #endif
8825 	/*
8826 	 * If last ACK falls within this segment's sequence numbers, record
8827 	 * the timestamp. NOTE that the test is modified according to the
8828 	 * latest proposal of the tcplw@cray.com list (Braden 1993/04/26).
8829 	 */
8830 	if (__predict_false(th->th_seq != tp->rcv_nxt)) {
8831 		return (0);
8832 	}
8833 	if (__predict_false(tp->snd_nxt != tp->snd_max)) {
8834 		return (0);
8835 	}
8836 	if (tiwin && tiwin != tp->snd_wnd) {
8837 		return (0);
8838 	}
8839 	if (__predict_false((tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN)))) {
8840 		return (0);
8841 	}
8842 	if (__predict_false((to->to_flags & TOF_TS) &&
8843 	    (TSTMP_LT(to->to_tsval, tp->ts_recent)))) {
8844 		return (0);
8845 	}
8846 	if (__predict_false((th->th_ack != tp->snd_una))) {
8847 		return (0);
8848 	}
8849 	if (__predict_false(tlen > sbspace(&so->so_rcv))) {
8850 		return (0);
8851 	}
8852 	if ((to->to_flags & TOF_TS) != 0 &&
8853 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
8854 		tp->ts_recent_age = tcp_ts_getticks();
8855 		tp->ts_recent = to->to_tsval;
8856 	}
8857 	rack = (struct tcp_rack *)tp->t_fb_ptr;
8858 	/*
8859 	 * This is a pure, in-sequence data packet with nothing on the
8860 	 * reassembly queue and we have enough buffer space to take it.
8861 	 */
8862 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
8863 
8864 #ifdef NETFLIX_SB_LIMITS
8865 	if (so->so_rcv.sb_shlim) {
8866 		mcnt = m_memcnt(m);
8867 		appended = 0;
8868 		if (counter_fo_get(so->so_rcv.sb_shlim, mcnt,
8869 		    CFO_NOSLEEP, NULL) == false) {
8870 			counter_u64_add(tcp_sb_shlim_fails, 1);
8871 			m_freem(m);
8872 			return (1);
8873 		}
8874 	}
8875 #endif
8876 	/* Clean receiver SACK report if present */
8877 	if (tp->rcv_numsacks)
8878 		tcp_clean_sackreport(tp);
8879 	KMOD_TCPSTAT_INC(tcps_preddat);
8880 	tp->rcv_nxt += tlen;
8881 	if (tlen &&
8882 	    ((tp->t_flags2 & TF2_FBYTES_COMPLETE) == 0) &&
8883 	    (tp->t_fbyte_in == 0)) {
8884 		tp->t_fbyte_in = ticks;
8885 		if (tp->t_fbyte_in == 0)
8886 			tp->t_fbyte_in = 1;
8887 		if (tp->t_fbyte_out && tp->t_fbyte_in)
8888 			tp->t_flags2 |= TF2_FBYTES_COMPLETE;
8889 	}
8890 	/*
8891 	 * Pull snd_wl1 up to prevent seq wrap relative to th_seq.
8892 	 */
8893 	tp->snd_wl1 = th->th_seq;
8894 	/*
8895 	 * Pull rcv_up up to prevent seq wrap relative to rcv_nxt.
8896 	 */
8897 	tp->rcv_up = tp->rcv_nxt;
8898 	KMOD_TCPSTAT_ADD(tcps_rcvpack, nsegs);
8899 	KMOD_TCPSTAT_ADD(tcps_rcvbyte, tlen);
8900 #ifdef TCPDEBUG
8901 	if (so->so_options & SO_DEBUG)
8902 		tcp_trace(TA_INPUT, ostate, tp,
8903 		    (void *)tcp_saveipgen, &tcp_savetcp, 0);
8904 #endif
8905 	newsize = tcp_autorcvbuf(m, th, so, tp, tlen);
8906 
8907 	/* Add data to socket buffer. */
8908 	SOCKBUF_LOCK(&so->so_rcv);
8909 	if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
8910 		m_freem(m);
8911 	} else {
8912 		/*
8913 		 * Set new socket buffer size. Give up when limit is
8914 		 * reached.
8915 		 */
8916 		if (newsize)
8917 			if (!sbreserve_locked(&so->so_rcv,
8918 			    newsize, so, NULL))
8919 				so->so_rcv.sb_flags &= ~SB_AUTOSIZE;
8920 		m_adj(m, drop_hdrlen);	/* delayed header drop */
8921 #ifdef NETFLIX_SB_LIMITS
8922 		appended =
8923 #endif
8924 			sbappendstream_locked(&so->so_rcv, m, 0);
8925 		ctf_calc_rwin(so, tp);
8926 	}
8927 	SOCKBUF_UNLOCK(&so->so_rcv);
8928 	tp->t_flags |= TF_WAKESOR;
8929 #ifdef NETFLIX_SB_LIMITS
8930 	if (so->so_rcv.sb_shlim && mcnt != appended)
8931 		counter_fo_release(so->so_rcv.sb_shlim, mcnt - appended);
8932 #endif
8933 	rack_handle_delayed_ack(tp, rack, tlen, 0);
8934 	if (tp->snd_una == tp->snd_max)
8935 		sack_filter_clear(&rack->r_ctl.rack_sf, tp->snd_una);
8936 	return (1);
8937 }
8938 
8939 /*
8940  * This subfunction is used to try to highly optimize the
8941  * fast path. We again allow window updates that are
8942  * in sequence to remain in the fast-path. We also add
8943  * in the __predict's to attempt to help the compiler.
8944  * Note that if we return a 0, then we can *not* process
8945  * it and the caller should push the packet into the
8946  * slow-path.
8947  */
8948 static int
8949 rack_fastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
8950     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
8951     uint32_t tiwin, int32_t nxt_pkt, uint32_t cts)
8952 {
8953 	int32_t acked;
8954 	int32_t nsegs;
8955 #ifdef TCPDEBUG
8956 	/*
8957 	 * The size of tcp_saveipgen must be the size of the max ip header,
8958 	 * now IPv6.
8959 	 */
8960 	u_char tcp_saveipgen[IP6_HDR_LEN];
8961 	struct tcphdr tcp_savetcp;
8962 	short ostate = 0;
8963 #endif
8964 	int32_t under_pacing = 0;
8965 	struct tcp_rack *rack;
8966 
8967 	if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
8968 		/* Old ack, behind (or duplicate to) the last one rcv'd */
8969 		return (0);
8970 	}
8971 	if (__predict_false(SEQ_GT(th->th_ack, tp->snd_max))) {
8972 		/* Above what we have sent? */
8973 		return (0);
8974 	}
8975 	if (__predict_false(tp->snd_nxt != tp->snd_max)) {
8976 		/* We are retransmitting */
8977 		return (0);
8978 	}
8979 	if (__predict_false(tiwin == 0)) {
8980 		/* zero window */
8981 		return (0);
8982 	}
8983 	if (__predict_false(tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN))) {
8984 		/* We need a SYN or a FIN, unlikely.. */
8985 		return (0);
8986 	}
8987 	if ((to->to_flags & TOF_TS) && __predict_false(TSTMP_LT(to->to_tsval, tp->ts_recent))) {
8988 		/* Timestamp is behind .. old ack with seq wrap? */
8989 		return (0);
8990 	}
8991 	if (__predict_false(IN_RECOVERY(tp->t_flags))) {
8992 		/* Still recovering */
8993 		return (0);
8994 	}
8995 	rack = (struct tcp_rack *)tp->t_fb_ptr;
8996 	if (rack->r_ctl.rc_sacked) {
8997 		/* We have sack holes on our scoreboard */
8998 		return (0);
8999 	}
9000 	/* Ok if we reach here, we can process a fast-ack */
9001 	if (rack->rc_gp_filled &&
9002 	    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
9003 		under_pacing = 1;
9004 	}
9005 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
9006 	rack_log_ack(tp, to, th);
9007 	/* Did the window get updated? */
9008 	if (tiwin != tp->snd_wnd) {
9009 		tp->snd_wnd = tiwin;
9010 		tp->snd_wl1 = th->th_seq;
9011 		if (tp->snd_wnd > tp->max_sndwnd)
9012 			tp->max_sndwnd = tp->snd_wnd;
9013 	}
9014 	/* Do we exit persists? */
9015 	if ((rack->rc_in_persist != 0) &&
9016 	    (tp->snd_wnd >= min((rack->r_ctl.rc_high_rwnd/2),
9017 			       rack->r_ctl.rc_pace_min_segs))) {
9018 		rack_exit_persist(tp, rack, cts);
9019 	}
9020 	/* Do we enter persists? */
9021 	if ((rack->rc_in_persist == 0) &&
9022 	    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), rack->r_ctl.rc_pace_min_segs)) &&
9023 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
9024 	    (tp->snd_max == tp->snd_una) &&
9025 	    sbavail(&tp->t_inpcb->inp_socket->so_snd) &&
9026 	    (sbavail(&tp->t_inpcb->inp_socket->so_snd) > tp->snd_wnd)) {
9027 		/*
9028 		 * Here the rwnd is less than
9029 		 * the pacing size, we are established,
9030 		 * nothing is outstanding, and there is
9031 		 * data to send. Enter persists.
9032 		 */
9033 		tp->snd_nxt = tp->snd_una;
9034 		rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
9035 	}
9036 	/*
9037 	 * If last ACK falls within this segment's sequence numbers, record
9038 	 * the timestamp. NOTE that the test is modified according to the
9039 	 * latest proposal of the tcplw@cray.com list (Braden 1993/04/26).
9040 	 */
9041 	if ((to->to_flags & TOF_TS) != 0 &&
9042 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
9043 		tp->ts_recent_age = tcp_ts_getticks();
9044 		tp->ts_recent = to->to_tsval;
9045 	}
9046 	/*
9047 	 * This is a pure ack for outstanding data.
9048 	 */
9049 	KMOD_TCPSTAT_INC(tcps_predack);
9050 
9051 	/*
9052 	 * "bad retransmit" recovery.
9053 	 */
9054 	if (tp->t_flags & TF_PREVVALID) {
9055 		tp->t_flags &= ~TF_PREVVALID;
9056 		if (tp->t_rxtshift == 1 &&
9057 		    (int)(ticks - tp->t_badrxtwin) < 0)
9058 			rack_cong_signal(tp, th, CC_RTO_ERR);
9059 	}
9060 	/*
9061 	 * Recalculate the transmit timer / rtt.
9062 	 *
9063 	 * Some boxes send broken timestamp replies during the SYN+ACK
9064 	 * phase, ignore timestamps of 0 or we could calculate a huge RTT
9065 	 * and blow up the retransmit timer.
9066 	 */
9067 	acked = BYTES_THIS_ACK(tp, th);
9068 
9069 #ifdef TCP_HHOOK
9070 	/* Run HHOOK_TCP_ESTABLISHED_IN helper hooks. */
9071 	hhook_run_tcp_est_in(tp, th, to);
9072 #endif
9073 
9074 	KMOD_TCPSTAT_ADD(tcps_rcvackpack, nsegs);
9075 	KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
9076 	sbdrop(&so->so_snd, acked);
9077 	if (acked) {
9078 		/* assure we are not backed off */
9079 		tp->t_rxtshift = 0;
9080 		rack->rc_tlp_in_progress = 0;
9081 		rack->r_ctl.rc_tlp_cnt_out = 0;
9082 		/*
9083 		 * If it is the RXT timer we want to
9084 		 * stop it, so we can restart a TLP.
9085 		 */
9086 		if (rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT)
9087 			rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
9088 #ifdef NETFLIX_HTTP_LOGGING
9089 		tcp_http_check_for_comp(rack->rc_tp, th->th_ack);
9090 #endif
9091 	}
9092 	/*
9093 	 * Let the congestion control algorithm update congestion control
9094 	 * related information. This typically means increasing the
9095 	 * congestion window.
9096 	 */
9097 	rack_ack_received(tp, rack, th, nsegs, CC_ACK, 0);
9098 
9099 	tp->snd_una = th->th_ack;
9100 	if (tp->snd_wnd < ctf_outstanding(tp)) {
9101 		/* The peer collapsed the window */
9102 		rack_collapsed_window(rack);
9103 	} else if (rack->rc_has_collapsed)
9104 		rack_un_collapse_window(rack);
9105 
9106 	/*
9107 	 * Pull snd_wl2 up to prevent seq wrap relative to th_ack.
9108 	 */
9109 	tp->snd_wl2 = th->th_ack;
9110 	tp->t_dupacks = 0;
9111 	m_freem(m);
9112 	/* ND6_HINT(tp);	 *//* Some progress has been made. */
9113 
9114 	/*
9115 	 * If all outstanding data are acked, stop retransmit timer,
9116 	 * otherwise restart timer using current (possibly backed-off)
9117 	 * value. If process is waiting for space, wakeup/selwakeup/signal.
9118 	 * If data are ready to send, let tcp_output decide between more
9119 	 * output or persist.
9120 	 */
9121 #ifdef TCPDEBUG
9122 	if (so->so_options & SO_DEBUG)
9123 		tcp_trace(TA_INPUT, ostate, tp,
9124 		    (void *)tcp_saveipgen,
9125 		    &tcp_savetcp, 0);
9126 #endif
9127 	if (under_pacing &&
9128 	    (rack->use_fixed_rate == 0) &&
9129 	    (rack->in_probe_rtt == 0) &&
9130 	    rack->rc_gp_dyn_mul &&
9131 	    rack->rc_always_pace) {
9132 		/* Check if we are dragging bottom */
9133 		rack_check_bottom_drag(tp, rack, so, acked);
9134 	}
9135 	if (tp->snd_una == tp->snd_max) {
9136 		rack->r_ctl.rc_went_idle_time = tcp_get_usecs(NULL);
9137 		if (rack->r_ctl.rc_went_idle_time == 0)
9138 			rack->r_ctl.rc_went_idle_time = 1;
9139 		rack_log_progress_event(rack, tp, 0, PROGRESS_CLEAR, __LINE__);
9140 		if (sbavail(&tp->t_inpcb->inp_socket->so_snd) == 0)
9141 			tp->t_acktime = 0;
9142 		rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
9143 	}
9144 	/* Wake up the socket if we have room to write more */
9145 	tp->t_flags |= TF_WAKESOW;
9146 	if (sbavail(&so->so_snd)) {
9147 		rack->r_wanted_output = 1;
9148 	}
9149 	return (1);
9150 }
9151 
9152 /*
9153  * Return value of 1, the TCB is unlocked and most
9154  * likely gone, return value of 0, the TCP is still
9155  * locked.
9156  */
9157 static int
9158 rack_do_syn_sent(struct mbuf *m, struct tcphdr *th, struct socket *so,
9159     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9160     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9161 {
9162 	int32_t ret_val = 0;
9163 	int32_t todrop;
9164 	int32_t ourfinisacked = 0;
9165 	struct tcp_rack *rack;
9166 
9167 	ctf_calc_rwin(so, tp);
9168 	/*
9169 	 * If the state is SYN_SENT: if seg contains an ACK, but not for our
9170 	 * SYN, drop the input. if seg contains a RST, then drop the
9171 	 * connection. if seg does not contain SYN, then drop it. Otherwise
9172 	 * this is an acceptable SYN segment initialize tp->rcv_nxt and
9173 	 * tp->irs if seg contains ack then advance tp->snd_una if seg
9174 	 * contains an ECE and ECN support is enabled, the stream is ECN
9175 	 * capable. if SYN has been acked change to ESTABLISHED else
9176 	 * SYN_RCVD state arrange for segment to be acked (eventually)
9177 	 * continue processing rest of data/controls.
9178 	 */
9179 	if ((thflags & TH_ACK) &&
9180 	    (SEQ_LEQ(th->th_ack, tp->iss) ||
9181 	    SEQ_GT(th->th_ack, tp->snd_max))) {
9182 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
9183 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9184 		return (1);
9185 	}
9186 	if ((thflags & (TH_ACK | TH_RST)) == (TH_ACK | TH_RST)) {
9187 		TCP_PROBE5(connect__refused, NULL, tp,
9188 		    mtod(m, const char *), tp, th);
9189 		tp = tcp_drop(tp, ECONNREFUSED);
9190 		ctf_do_drop(m, tp);
9191 		return (1);
9192 	}
9193 	if (thflags & TH_RST) {
9194 		ctf_do_drop(m, tp);
9195 		return (1);
9196 	}
9197 	if (!(thflags & TH_SYN)) {
9198 		ctf_do_drop(m, tp);
9199 		return (1);
9200 	}
9201 	tp->irs = th->th_seq;
9202 	tcp_rcvseqinit(tp);
9203 	rack = (struct tcp_rack *)tp->t_fb_ptr;
9204 	if (thflags & TH_ACK) {
9205 		int tfo_partial = 0;
9206 
9207 		KMOD_TCPSTAT_INC(tcps_connects);
9208 		soisconnected(so);
9209 #ifdef MAC
9210 		mac_socketpeer_set_from_mbuf(m, so);
9211 #endif
9212 		/* Do window scaling on this connection? */
9213 		if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
9214 		    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
9215 			tp->rcv_scale = tp->request_r_scale;
9216 		}
9217 		tp->rcv_adv += min(tp->rcv_wnd,
9218 		    TCP_MAXWIN << tp->rcv_scale);
9219 		/*
9220 		 * If not all the data that was sent in the TFO SYN
9221 		 * has been acked, resend the remainder right away.
9222 		 */
9223 		if (IS_FASTOPEN(tp->t_flags) &&
9224 		    (tp->snd_una != tp->snd_max)) {
9225 			tp->snd_nxt = th->th_ack;
9226 			tfo_partial = 1;
9227 		}
9228 		/*
9229 		 * If there's data, delay ACK; if there's also a FIN ACKNOW
9230 		 * will be turned on later.
9231 		 */
9232 		if (DELAY_ACK(tp, tlen) && tlen != 0 && !tfo_partial) {
9233 			rack_timer_cancel(tp, rack,
9234 					  rack->r_ctl.rc_rcvtime, __LINE__);
9235 			tp->t_flags |= TF_DELACK;
9236 		} else {
9237 			rack->r_wanted_output = 1;
9238 			tp->t_flags |= TF_ACKNOW;
9239 			rack->rc_dack_toggle = 0;
9240 		}
9241 		if (((thflags & (TH_CWR | TH_ECE)) == TH_ECE) &&
9242 		    (V_tcp_do_ecn == 1)) {
9243 			tp->t_flags2 |= TF2_ECN_PERMIT;
9244 			KMOD_TCPSTAT_INC(tcps_ecn_shs);
9245 		}
9246 		if (SEQ_GT(th->th_ack, tp->snd_una)) {
9247 			/*
9248 			 * We advance snd_una for the
9249 			 * fast open case. If th_ack is
9250 			 * acknowledging data beyond
9251 			 * snd_una we can't just call
9252 			 * ack-processing since the
9253 			 * data stream in our send-map
9254 			 * will start at snd_una + 1 (one
9255 			 * beyond the SYN). If its just
9256 			 * equal we don't need to do that
9257 			 * and there is no send_map.
9258 			 */
9259 			tp->snd_una++;
9260 		}
9261 		/*
9262 		 * Received <SYN,ACK> in SYN_SENT[*] state. Transitions:
9263 		 * SYN_SENT  --> ESTABLISHED SYN_SENT* --> FIN_WAIT_1
9264 		 */
9265 		tp->t_starttime = ticks;
9266 		if (tp->t_flags & TF_NEEDFIN) {
9267 			tcp_state_change(tp, TCPS_FIN_WAIT_1);
9268 			tp->t_flags &= ~TF_NEEDFIN;
9269 			thflags &= ~TH_SYN;
9270 		} else {
9271 			tcp_state_change(tp, TCPS_ESTABLISHED);
9272 			TCP_PROBE5(connect__established, NULL, tp,
9273 			    mtod(m, const char *), tp, th);
9274 			rack_cc_conn_init(tp);
9275 		}
9276 	} else {
9277 		/*
9278 		 * Received initial SYN in SYN-SENT[*] state => simultaneous
9279 		 * open.  If segment contains CC option and there is a
9280 		 * cached CC, apply TAO test. If it succeeds, connection is *
9281 		 * half-synchronized. Otherwise, do 3-way handshake:
9282 		 * SYN-SENT -> SYN-RECEIVED SYN-SENT* -> SYN-RECEIVED* If
9283 		 * there was no CC option, clear cached CC value.
9284 		 */
9285 		tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
9286 		tcp_state_change(tp, TCPS_SYN_RECEIVED);
9287 	}
9288 	INP_WLOCK_ASSERT(tp->t_inpcb);
9289 	/*
9290 	 * Advance th->th_seq to correspond to first data byte. If data,
9291 	 * trim to stay within window, dropping FIN if necessary.
9292 	 */
9293 	th->th_seq++;
9294 	if (tlen > tp->rcv_wnd) {
9295 		todrop = tlen - tp->rcv_wnd;
9296 		m_adj(m, -todrop);
9297 		tlen = tp->rcv_wnd;
9298 		thflags &= ~TH_FIN;
9299 		KMOD_TCPSTAT_INC(tcps_rcvpackafterwin);
9300 		KMOD_TCPSTAT_ADD(tcps_rcvbyteafterwin, todrop);
9301 	}
9302 	tp->snd_wl1 = th->th_seq - 1;
9303 	tp->rcv_up = th->th_seq;
9304 	/*
9305 	 * Client side of transaction: already sent SYN and data. If the
9306 	 * remote host used T/TCP to validate the SYN, our data will be
9307 	 * ACK'd; if so, enter normal data segment processing in the middle
9308 	 * of step 5, ack processing. Otherwise, goto step 6.
9309 	 */
9310 	if (thflags & TH_ACK) {
9311 		/* For syn-sent we need to possibly update the rtt */
9312 		if ((to->to_flags & TOF_TS) != 0 && to->to_tsecr) {
9313 			uint32_t t;
9314 
9315 			t = tcp_ts_getticks() - to->to_tsecr;
9316 			if (!tp->t_rttlow || tp->t_rttlow > t)
9317 				tp->t_rttlow = t;
9318 			tcp_rack_xmit_timer(rack, t + 1, 1, (t * HPTS_USEC_IN_MSEC), 0, NULL, 2);
9319 			tcp_rack_xmit_timer_commit(rack, tp);
9320 		}
9321 		if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val))
9322 			return (ret_val);
9323 		/* We may have changed to FIN_WAIT_1 above */
9324 		if (tp->t_state == TCPS_FIN_WAIT_1) {
9325 			/*
9326 			 * In FIN_WAIT_1 STATE in addition to the processing
9327 			 * for the ESTABLISHED state if our FIN is now
9328 			 * acknowledged then enter FIN_WAIT_2.
9329 			 */
9330 			if (ourfinisacked) {
9331 				/*
9332 				 * If we can't receive any more data, then
9333 				 * closing user can proceed. Starting the
9334 				 * timer is contrary to the specification,
9335 				 * but if we don't get a FIN we'll hang
9336 				 * forever.
9337 				 *
9338 				 * XXXjl: we should release the tp also, and
9339 				 * use a compressed state.
9340 				 */
9341 				if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
9342 					soisdisconnected(so);
9343 					tcp_timer_activate(tp, TT_2MSL,
9344 					    (tcp_fast_finwait2_recycle ?
9345 					    tcp_finwait2_timeout :
9346 					    TP_MAXIDLE(tp)));
9347 				}
9348 				tcp_state_change(tp, TCPS_FIN_WAIT_2);
9349 			}
9350 		}
9351 	}
9352 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9353 	   tiwin, thflags, nxt_pkt));
9354 }
9355 
9356 /*
9357  * Return value of 1, the TCB is unlocked and most
9358  * likely gone, return value of 0, the TCP is still
9359  * locked.
9360  */
9361 static int
9362 rack_do_syn_recv(struct mbuf *m, struct tcphdr *th, struct socket *so,
9363     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9364     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9365 {
9366 	struct tcp_rack *rack;
9367 	int32_t ret_val = 0;
9368 	int32_t ourfinisacked = 0;
9369 
9370 	ctf_calc_rwin(so, tp);
9371 	if ((thflags & TH_ACK) &&
9372 	    (SEQ_LEQ(th->th_ack, tp->snd_una) ||
9373 	    SEQ_GT(th->th_ack, tp->snd_max))) {
9374 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
9375 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9376 		return (1);
9377 	}
9378 	rack = (struct tcp_rack *)tp->t_fb_ptr;
9379 	if (IS_FASTOPEN(tp->t_flags)) {
9380 		/*
9381 		 * When a TFO connection is in SYN_RECEIVED, the
9382 		 * only valid packets are the initial SYN, a
9383 		 * retransmit/copy of the initial SYN (possibly with
9384 		 * a subset of the original data), a valid ACK, a
9385 		 * FIN, or a RST.
9386 		 */
9387 		if ((thflags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) {
9388 			tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
9389 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9390 			return (1);
9391 		} else if (thflags & TH_SYN) {
9392 			/* non-initial SYN is ignored */
9393 			if ((rack->r_ctl.rc_hpts_flags & PACE_TMR_RXT) ||
9394 			    (rack->r_ctl.rc_hpts_flags & PACE_TMR_TLP) ||
9395 			    (rack->r_ctl.rc_hpts_flags & PACE_TMR_RACK)) {
9396 				ctf_do_drop(m, NULL);
9397 				return (0);
9398 			}
9399 		} else if (!(thflags & (TH_ACK | TH_FIN | TH_RST))) {
9400 			ctf_do_drop(m, NULL);
9401 			return (0);
9402 		}
9403 	}
9404 	if ((thflags & TH_RST) ||
9405 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9406 		return (ctf_process_rst(m, th, so, tp));
9407 	/*
9408 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9409 	 * it's less than ts_recent, drop it.
9410 	 */
9411 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9412 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9413 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9414 			return (ret_val);
9415 	}
9416 	/*
9417 	 * In the SYN-RECEIVED state, validate that the packet belongs to
9418 	 * this connection before trimming the data to fit the receive
9419 	 * window.  Check the sequence number versus IRS since we know the
9420 	 * sequence numbers haven't wrapped.  This is a partial fix for the
9421 	 * "LAND" DoS attack.
9422 	 */
9423 	if (SEQ_LT(th->th_seq, tp->irs)) {
9424 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
9425 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9426 		return (1);
9427 	}
9428 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9429 		return (ret_val);
9430 	}
9431 	/*
9432 	 * If last ACK falls within this segment's sequence numbers, record
9433 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9434 	 * from the latest proposal of the tcplw@cray.com list (Braden
9435 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9436 	 * with our earlier PAWS tests, so this check should be solely
9437 	 * predicated on the sequence space of this segment. 3) That we
9438 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9439 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9440 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9441 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9442 	 * p.869. In such cases, we can still calculate the RTT correctly
9443 	 * when RCV.NXT == Last.ACK.Sent.
9444 	 */
9445 	if ((to->to_flags & TOF_TS) != 0 &&
9446 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9447 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9448 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9449 		tp->ts_recent_age = tcp_ts_getticks();
9450 		tp->ts_recent = to->to_tsval;
9451 	}
9452 	tp->snd_wnd = tiwin;
9453 	/*
9454 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9455 	 * is on (half-synchronized state), then queue data for later
9456 	 * processing; else drop segment and return.
9457 	 */
9458 	if ((thflags & TH_ACK) == 0) {
9459 		if (IS_FASTOPEN(tp->t_flags)) {
9460 			rack_cc_conn_init(tp);
9461 		}
9462 		return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9463 		    tiwin, thflags, nxt_pkt));
9464 	}
9465 	KMOD_TCPSTAT_INC(tcps_connects);
9466 	soisconnected(so);
9467 	/* Do window scaling? */
9468 	if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
9469 	    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
9470 		tp->rcv_scale = tp->request_r_scale;
9471 	}
9472 	/*
9473 	 * Make transitions: SYN-RECEIVED  -> ESTABLISHED SYN-RECEIVED* ->
9474 	 * FIN-WAIT-1
9475 	 */
9476 	tp->t_starttime = ticks;
9477 	if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) {
9478 		tcp_fastopen_decrement_counter(tp->t_tfo_pending);
9479 		tp->t_tfo_pending = NULL;
9480 	}
9481 	if (tp->t_flags & TF_NEEDFIN) {
9482 		tcp_state_change(tp, TCPS_FIN_WAIT_1);
9483 		tp->t_flags &= ~TF_NEEDFIN;
9484 	} else {
9485 		tcp_state_change(tp, TCPS_ESTABLISHED);
9486 		TCP_PROBE5(accept__established, NULL, tp,
9487 		    mtod(m, const char *), tp, th);
9488 		/*
9489 		 * TFO connections call cc_conn_init() during SYN
9490 		 * processing.  Calling it again here for such connections
9491 		 * is not harmless as it would undo the snd_cwnd reduction
9492 		 * that occurs when a TFO SYN|ACK is retransmitted.
9493 		 */
9494 		if (!IS_FASTOPEN(tp->t_flags))
9495 			rack_cc_conn_init(tp);
9496 	}
9497 	/*
9498 	 * Account for the ACK of our SYN prior to
9499 	 * regular ACK processing below, except for
9500 	 * simultaneous SYN, which is handled later.
9501 	 */
9502 	if (SEQ_GT(th->th_ack, tp->snd_una) && !(tp->t_flags & TF_NEEDSYN))
9503 		tp->snd_una++;
9504 	/*
9505 	 * If segment contains data or ACK, will call tcp_reass() later; if
9506 	 * not, do so now to pass queued data to user.
9507 	 */
9508 	if (tlen == 0 && (thflags & TH_FIN) == 0)
9509 		(void) tcp_reass(tp, (struct tcphdr *)0, NULL, 0,
9510 		    (struct mbuf *)0);
9511 	tp->snd_wl1 = th->th_seq - 1;
9512 	/* For syn-recv we need to possibly update the rtt */
9513 	if ((to->to_flags & TOF_TS) != 0 && to->to_tsecr) {
9514 		uint32_t t;
9515 
9516 		t = tcp_ts_getticks() - to->to_tsecr;
9517 		if (!tp->t_rttlow || tp->t_rttlow > t)
9518 			tp->t_rttlow = t;
9519 		tcp_rack_xmit_timer(rack, t + 1, 1, (t * HPTS_USEC_IN_MSEC), 0, NULL, 2);
9520 		tcp_rack_xmit_timer_commit(rack, tp);
9521 	}
9522 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
9523 		return (ret_val);
9524 	}
9525 	if (tp->t_state == TCPS_FIN_WAIT_1) {
9526 		/* We could have went to FIN_WAIT_1 (or EST) above */
9527 		/*
9528 		 * In FIN_WAIT_1 STATE in addition to the processing for the
9529 		 * ESTABLISHED state if our FIN is now acknowledged then
9530 		 * enter FIN_WAIT_2.
9531 		 */
9532 		if (ourfinisacked) {
9533 			/*
9534 			 * If we can't receive any more data, then closing
9535 			 * user can proceed. Starting the timer is contrary
9536 			 * to the specification, but if we don't get a FIN
9537 			 * we'll hang forever.
9538 			 *
9539 			 * XXXjl: we should release the tp also, and use a
9540 			 * compressed state.
9541 			 */
9542 			if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
9543 				soisdisconnected(so);
9544 				tcp_timer_activate(tp, TT_2MSL,
9545 				    (tcp_fast_finwait2_recycle ?
9546 				    tcp_finwait2_timeout :
9547 				    TP_MAXIDLE(tp)));
9548 			}
9549 			tcp_state_change(tp, TCPS_FIN_WAIT_2);
9550 		}
9551 	}
9552 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9553 	    tiwin, thflags, nxt_pkt));
9554 }
9555 
9556 /*
9557  * Return value of 1, the TCB is unlocked and most
9558  * likely gone, return value of 0, the TCP is still
9559  * locked.
9560  */
9561 static int
9562 rack_do_established(struct mbuf *m, struct tcphdr *th, struct socket *so,
9563     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9564     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9565 {
9566 	int32_t ret_val = 0;
9567 	struct tcp_rack *rack;
9568 
9569 	/*
9570 	 * Header prediction: check for the two common cases of a
9571 	 * uni-directional data xfer.  If the packet has no control flags,
9572 	 * is in-sequence, the window didn't change and we're not
9573 	 * retransmitting, it's a candidate.  If the length is zero and the
9574 	 * ack moved forward, we're the sender side of the xfer.  Just free
9575 	 * the data acked & wake any higher level process that was blocked
9576 	 * waiting for space.  If the length is non-zero and the ack didn't
9577 	 * move, we're the receiver side.  If we're getting packets in-order
9578 	 * (the reassembly queue is empty), add the data toc The socket
9579 	 * buffer and note that we need a delayed ack. Make sure that the
9580 	 * hidden state-flags are also off. Since we check for
9581 	 * TCPS_ESTABLISHED first, it can only be TH_NEEDSYN.
9582 	 */
9583 	rack = (struct tcp_rack *)tp->t_fb_ptr;
9584 	if (__predict_true(((to->to_flags & TOF_SACK) == 0)) &&
9585 	    __predict_true((thflags & (TH_SYN | TH_FIN | TH_RST | TH_ACK)) == TH_ACK) &&
9586 	    __predict_true(SEGQ_EMPTY(tp)) &&
9587 	    __predict_true(th->th_seq == tp->rcv_nxt)) {
9588 		if (tlen == 0) {
9589 			if (rack_fastack(m, th, so, tp, to, drop_hdrlen, tlen,
9590 			    tiwin, nxt_pkt, rack->r_ctl.rc_rcvtime)) {
9591 				return (0);
9592 			}
9593 		} else {
9594 			if (rack_do_fastnewdata(m, th, so, tp, to, drop_hdrlen, tlen,
9595 			    tiwin, nxt_pkt, iptos)) {
9596 				return (0);
9597 			}
9598 		}
9599 	}
9600 	ctf_calc_rwin(so, tp);
9601 
9602 	if ((thflags & TH_RST) ||
9603 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9604 		return (ctf_process_rst(m, th, so, tp));
9605 
9606 	/*
9607 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9608 	 * synchronized state.
9609 	 */
9610 	if (thflags & TH_SYN) {
9611 		ctf_challenge_ack(m, th, tp, &ret_val);
9612 		return (ret_val);
9613 	}
9614 	/*
9615 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9616 	 * it's less than ts_recent, drop it.
9617 	 */
9618 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9619 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9620 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9621 			return (ret_val);
9622 	}
9623 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9624 		return (ret_val);
9625 	}
9626 	/*
9627 	 * If last ACK falls within this segment's sequence numbers, record
9628 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9629 	 * from the latest proposal of the tcplw@cray.com list (Braden
9630 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9631 	 * with our earlier PAWS tests, so this check should be solely
9632 	 * predicated on the sequence space of this segment. 3) That we
9633 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9634 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9635 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9636 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9637 	 * p.869. In such cases, we can still calculate the RTT correctly
9638 	 * when RCV.NXT == Last.ACK.Sent.
9639 	 */
9640 	if ((to->to_flags & TOF_TS) != 0 &&
9641 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9642 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9643 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9644 		tp->ts_recent_age = tcp_ts_getticks();
9645 		tp->ts_recent = to->to_tsval;
9646 	}
9647 	/*
9648 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9649 	 * is on (half-synchronized state), then queue data for later
9650 	 * processing; else drop segment and return.
9651 	 */
9652 	if ((thflags & TH_ACK) == 0) {
9653 		if (tp->t_flags & TF_NEEDSYN) {
9654 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9655 			    tiwin, thflags, nxt_pkt));
9656 
9657 		} else if (tp->t_flags & TF_ACKNOW) {
9658 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9659 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output= 1;
9660 			return (ret_val);
9661 		} else {
9662 			ctf_do_drop(m, NULL);
9663 			return (0);
9664 		}
9665 	}
9666 	/*
9667 	 * Ack processing.
9668 	 */
9669 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) {
9670 		return (ret_val);
9671 	}
9672 	if (sbavail(&so->so_snd)) {
9673 		if (ctf_progress_timeout_check(tp, true)) {
9674 			rack_log_progress_event(rack, tp, tick, PROGRESS_DROP, __LINE__);
9675 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
9676 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9677 			return (1);
9678 		}
9679 	}
9680 	/* State changes only happen in rack_process_data() */
9681 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9682 	    tiwin, thflags, nxt_pkt));
9683 }
9684 
9685 /*
9686  * Return value of 1, the TCB is unlocked and most
9687  * likely gone, return value of 0, the TCP is still
9688  * locked.
9689  */
9690 static int
9691 rack_do_close_wait(struct mbuf *m, struct tcphdr *th, struct socket *so,
9692     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9693     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9694 {
9695 	int32_t ret_val = 0;
9696 
9697 	ctf_calc_rwin(so, tp);
9698 	if ((thflags & TH_RST) ||
9699 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9700 		return (ctf_process_rst(m, th, so, tp));
9701 	/*
9702 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9703 	 * synchronized state.
9704 	 */
9705 	if (thflags & TH_SYN) {
9706 		ctf_challenge_ack(m, th, tp, &ret_val);
9707 		return (ret_val);
9708 	}
9709 	/*
9710 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9711 	 * it's less than ts_recent, drop it.
9712 	 */
9713 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9714 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9715 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9716 			return (ret_val);
9717 	}
9718 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9719 		return (ret_val);
9720 	}
9721 	/*
9722 	 * If last ACK falls within this segment's sequence numbers, record
9723 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9724 	 * from the latest proposal of the tcplw@cray.com list (Braden
9725 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9726 	 * with our earlier PAWS tests, so this check should be solely
9727 	 * predicated on the sequence space of this segment. 3) That we
9728 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9729 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9730 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9731 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9732 	 * p.869. In such cases, we can still calculate the RTT correctly
9733 	 * when RCV.NXT == Last.ACK.Sent.
9734 	 */
9735 	if ((to->to_flags & TOF_TS) != 0 &&
9736 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9737 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9738 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9739 		tp->ts_recent_age = tcp_ts_getticks();
9740 		tp->ts_recent = to->to_tsval;
9741 	}
9742 	/*
9743 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9744 	 * is on (half-synchronized state), then queue data for later
9745 	 * processing; else drop segment and return.
9746 	 */
9747 	if ((thflags & TH_ACK) == 0) {
9748 		if (tp->t_flags & TF_NEEDSYN) {
9749 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9750 			    tiwin, thflags, nxt_pkt));
9751 
9752 		} else if (tp->t_flags & TF_ACKNOW) {
9753 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9754 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
9755 			return (ret_val);
9756 		} else {
9757 			ctf_do_drop(m, NULL);
9758 			return (0);
9759 		}
9760 	}
9761 	/*
9762 	 * Ack processing.
9763 	 */
9764 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) {
9765 		return (ret_val);
9766 	}
9767 	if (sbavail(&so->so_snd)) {
9768 		if (ctf_progress_timeout_check(tp, true)) {
9769 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
9770 						tp, tick, PROGRESS_DROP, __LINE__);
9771 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
9772 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9773 			return (1);
9774 		}
9775 	}
9776 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9777 	    tiwin, thflags, nxt_pkt));
9778 }
9779 
9780 static int
9781 rack_check_data_after_close(struct mbuf *m,
9782     struct tcpcb *tp, int32_t *tlen, struct tcphdr *th, struct socket *so)
9783 {
9784 	struct tcp_rack *rack;
9785 
9786 	rack = (struct tcp_rack *)tp->t_fb_ptr;
9787 	if (rack->rc_allow_data_af_clo == 0) {
9788 	close_now:
9789 		tcp_log_end_status(tp, TCP_EI_STATUS_DATA_A_CLOSE);
9790 		/* tcp_close will kill the inp pre-log the Reset */
9791 		tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
9792 		tp = tcp_close(tp);
9793 		KMOD_TCPSTAT_INC(tcps_rcvafterclose);
9794 		ctf_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, (*tlen));
9795 		return (1);
9796 	}
9797 	if (sbavail(&so->so_snd) == 0)
9798 		goto close_now;
9799 	/* Ok we allow data that is ignored and a followup reset */
9800 	tcp_log_end_status(tp, TCP_EI_STATUS_DATA_A_CLOSE);
9801 	tp->rcv_nxt = th->th_seq + *tlen;
9802 	tp->t_flags2 |= TF2_DROP_AF_DATA;
9803 	rack->r_wanted_output = 1;
9804 	*tlen = 0;
9805 	return (0);
9806 }
9807 
9808 /*
9809  * Return value of 1, the TCB is unlocked and most
9810  * likely gone, return value of 0, the TCP is still
9811  * locked.
9812  */
9813 static int
9814 rack_do_fin_wait_1(struct mbuf *m, struct tcphdr *th, struct socket *so,
9815     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9816     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9817 {
9818 	int32_t ret_val = 0;
9819 	int32_t ourfinisacked = 0;
9820 
9821 	ctf_calc_rwin(so, tp);
9822 
9823 	if ((thflags & TH_RST) ||
9824 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9825 		return (ctf_process_rst(m, th, so, tp));
9826 	/*
9827 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9828 	 * synchronized state.
9829 	 */
9830 	if (thflags & TH_SYN) {
9831 		ctf_challenge_ack(m, th, tp, &ret_val);
9832 		return (ret_val);
9833 	}
9834 	/*
9835 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9836 	 * it's less than ts_recent, drop it.
9837 	 */
9838 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9839 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9840 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9841 			return (ret_val);
9842 	}
9843 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9844 		return (ret_val);
9845 	}
9846 	/*
9847 	 * If new data are received on a connection after the user processes
9848 	 * are gone, then RST the other end.
9849 	 */
9850 	if ((so->so_state & SS_NOFDREF) && tlen) {
9851 		if (rack_check_data_after_close(m, tp, &tlen, th, so))
9852 			return (1);
9853 	}
9854 	/*
9855 	 * If last ACK falls within this segment's sequence numbers, record
9856 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9857 	 * from the latest proposal of the tcplw@cray.com list (Braden
9858 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9859 	 * with our earlier PAWS tests, so this check should be solely
9860 	 * predicated on the sequence space of this segment. 3) That we
9861 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9862 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9863 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9864 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9865 	 * p.869. In such cases, we can still calculate the RTT correctly
9866 	 * when RCV.NXT == Last.ACK.Sent.
9867 	 */
9868 	if ((to->to_flags & TOF_TS) != 0 &&
9869 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9870 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9871 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9872 		tp->ts_recent_age = tcp_ts_getticks();
9873 		tp->ts_recent = to->to_tsval;
9874 	}
9875 	/*
9876 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9877 	 * is on (half-synchronized state), then queue data for later
9878 	 * processing; else drop segment and return.
9879 	 */
9880 	if ((thflags & TH_ACK) == 0) {
9881 		if (tp->t_flags & TF_NEEDSYN) {
9882 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9883 			    tiwin, thflags, nxt_pkt));
9884 		} else if (tp->t_flags & TF_ACKNOW) {
9885 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9886 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
9887 			return (ret_val);
9888 		} else {
9889 			ctf_do_drop(m, NULL);
9890 			return (0);
9891 		}
9892 	}
9893 	/*
9894 	 * Ack processing.
9895 	 */
9896 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
9897 		return (ret_val);
9898 	}
9899 	if (ourfinisacked) {
9900 		/*
9901 		 * If we can't receive any more data, then closing user can
9902 		 * proceed. Starting the timer is contrary to the
9903 		 * specification, but if we don't get a FIN we'll hang
9904 		 * forever.
9905 		 *
9906 		 * XXXjl: we should release the tp also, and use a
9907 		 * compressed state.
9908 		 */
9909 		if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
9910 			soisdisconnected(so);
9911 			tcp_timer_activate(tp, TT_2MSL,
9912 			    (tcp_fast_finwait2_recycle ?
9913 			    tcp_finwait2_timeout :
9914 			    TP_MAXIDLE(tp)));
9915 		}
9916 		tcp_state_change(tp, TCPS_FIN_WAIT_2);
9917 	}
9918 	if (sbavail(&so->so_snd)) {
9919 		if (ctf_progress_timeout_check(tp, true)) {
9920 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
9921 						tp, tick, PROGRESS_DROP, __LINE__);
9922 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
9923 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9924 			return (1);
9925 		}
9926 	}
9927 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
9928 	    tiwin, thflags, nxt_pkt));
9929 }
9930 
9931 /*
9932  * Return value of 1, the TCB is unlocked and most
9933  * likely gone, return value of 0, the TCP is still
9934  * locked.
9935  */
9936 static int
9937 rack_do_closing(struct mbuf *m, struct tcphdr *th, struct socket *so,
9938     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9939     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9940 {
9941 	int32_t ret_val = 0;
9942 	int32_t ourfinisacked = 0;
9943 
9944 	ctf_calc_rwin(so, tp);
9945 
9946 	if ((thflags & TH_RST) ||
9947 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9948 		return (ctf_process_rst(m, th, so, tp));
9949 	/*
9950 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9951 	 * synchronized state.
9952 	 */
9953 	if (thflags & TH_SYN) {
9954 		ctf_challenge_ack(m, th, tp, &ret_val);
9955 		return (ret_val);
9956 	}
9957 	/*
9958 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9959 	 * it's less than ts_recent, drop it.
9960 	 */
9961 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9962 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9963 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9964 			return (ret_val);
9965 	}
9966 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9967 		return (ret_val);
9968 	}
9969 	/*
9970 	 * If new data are received on a connection after the user processes
9971 	 * are gone, then RST the other end.
9972 	 */
9973 	if ((so->so_state & SS_NOFDREF) && tlen) {
9974 		if (rack_check_data_after_close(m, tp, &tlen, th, so))
9975 			return (1);
9976 	}
9977 	/*
9978 	 * If last ACK falls within this segment's sequence numbers, record
9979 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9980 	 * from the latest proposal of the tcplw@cray.com list (Braden
9981 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9982 	 * with our earlier PAWS tests, so this check should be solely
9983 	 * predicated on the sequence space of this segment. 3) That we
9984 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9985 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9986 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9987 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9988 	 * p.869. In such cases, we can still calculate the RTT correctly
9989 	 * when RCV.NXT == Last.ACK.Sent.
9990 	 */
9991 	if ((to->to_flags & TOF_TS) != 0 &&
9992 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9993 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9994 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9995 		tp->ts_recent_age = tcp_ts_getticks();
9996 		tp->ts_recent = to->to_tsval;
9997 	}
9998 	/*
9999 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
10000 	 * is on (half-synchronized state), then queue data for later
10001 	 * processing; else drop segment and return.
10002 	 */
10003 	if ((thflags & TH_ACK) == 0) {
10004 		if (tp->t_flags & TF_NEEDSYN) {
10005 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10006 			    tiwin, thflags, nxt_pkt));
10007 		} else if (tp->t_flags & TF_ACKNOW) {
10008 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
10009 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output= 1;
10010 			return (ret_val);
10011 		} else {
10012 			ctf_do_drop(m, NULL);
10013 			return (0);
10014 		}
10015 	}
10016 	/*
10017 	 * Ack processing.
10018 	 */
10019 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
10020 		return (ret_val);
10021 	}
10022 	if (ourfinisacked) {
10023 		tcp_twstart(tp);
10024 		m_freem(m);
10025 		return (1);
10026 	}
10027 	if (sbavail(&so->so_snd)) {
10028 		if (ctf_progress_timeout_check(tp, true)) {
10029 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
10030 						tp, tick, PROGRESS_DROP, __LINE__);
10031 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
10032 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
10033 			return (1);
10034 		}
10035 	}
10036 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10037 	    tiwin, thflags, nxt_pkt));
10038 }
10039 
10040 /*
10041  * Return value of 1, the TCB is unlocked and most
10042  * likely gone, return value of 0, the TCP is still
10043  * locked.
10044  */
10045 static int
10046 rack_do_lastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
10047     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
10048     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
10049 {
10050 	int32_t ret_val = 0;
10051 	int32_t ourfinisacked = 0;
10052 
10053 	ctf_calc_rwin(so, tp);
10054 
10055 	if ((thflags & TH_RST) ||
10056 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
10057 		return (ctf_process_rst(m, th, so, tp));
10058 	/*
10059 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
10060 	 * synchronized state.
10061 	 */
10062 	if (thflags & TH_SYN) {
10063 		ctf_challenge_ack(m, th, tp, &ret_val);
10064 		return (ret_val);
10065 	}
10066 	/*
10067 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
10068 	 * it's less than ts_recent, drop it.
10069 	 */
10070 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
10071 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
10072 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
10073 			return (ret_val);
10074 	}
10075 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
10076 		return (ret_val);
10077 	}
10078 	/*
10079 	 * If new data are received on a connection after the user processes
10080 	 * are gone, then RST the other end.
10081 	 */
10082 	if ((so->so_state & SS_NOFDREF) && tlen) {
10083 		if (rack_check_data_after_close(m, tp, &tlen, th, so))
10084 			return (1);
10085 	}
10086 	/*
10087 	 * If last ACK falls within this segment's sequence numbers, record
10088 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
10089 	 * from the latest proposal of the tcplw@cray.com list (Braden
10090 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
10091 	 * with our earlier PAWS tests, so this check should be solely
10092 	 * predicated on the sequence space of this segment. 3) That we
10093 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
10094 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
10095 	 * SEG.Len, This modified check allows us to overcome RFC1323's
10096 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
10097 	 * p.869. In such cases, we can still calculate the RTT correctly
10098 	 * when RCV.NXT == Last.ACK.Sent.
10099 	 */
10100 	if ((to->to_flags & TOF_TS) != 0 &&
10101 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
10102 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
10103 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
10104 		tp->ts_recent_age = tcp_ts_getticks();
10105 		tp->ts_recent = to->to_tsval;
10106 	}
10107 	/*
10108 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
10109 	 * is on (half-synchronized state), then queue data for later
10110 	 * processing; else drop segment and return.
10111 	 */
10112 	if ((thflags & TH_ACK) == 0) {
10113 		if (tp->t_flags & TF_NEEDSYN) {
10114 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10115 			    tiwin, thflags, nxt_pkt));
10116 		} else if (tp->t_flags & TF_ACKNOW) {
10117 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
10118 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
10119 			return (ret_val);
10120 		} else {
10121 			ctf_do_drop(m, NULL);
10122 			return (0);
10123 		}
10124 	}
10125 	/*
10126 	 * case TCPS_LAST_ACK: Ack processing.
10127 	 */
10128 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
10129 		return (ret_val);
10130 	}
10131 	if (ourfinisacked) {
10132 		tp = tcp_close(tp);
10133 		ctf_do_drop(m, tp);
10134 		return (1);
10135 	}
10136 	if (sbavail(&so->so_snd)) {
10137 		if (ctf_progress_timeout_check(tp, true)) {
10138 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
10139 						tp, tick, PROGRESS_DROP, __LINE__);
10140 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
10141 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
10142 			return (1);
10143 		}
10144 	}
10145 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10146 	    tiwin, thflags, nxt_pkt));
10147 }
10148 
10149 /*
10150  * Return value of 1, the TCB is unlocked and most
10151  * likely gone, return value of 0, the TCP is still
10152  * locked.
10153  */
10154 static int
10155 rack_do_fin_wait_2(struct mbuf *m, struct tcphdr *th, struct socket *so,
10156     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
10157     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
10158 {
10159 	int32_t ret_val = 0;
10160 	int32_t ourfinisacked = 0;
10161 
10162 	ctf_calc_rwin(so, tp);
10163 
10164 	/* Reset receive buffer auto scaling when not in bulk receive mode. */
10165 	if ((thflags & TH_RST) ||
10166 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
10167 		return (ctf_process_rst(m, th, so, tp));
10168 	/*
10169 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
10170 	 * synchronized state.
10171 	 */
10172 	if (thflags & TH_SYN) {
10173 		ctf_challenge_ack(m, th, tp, &ret_val);
10174 		return (ret_val);
10175 	}
10176 	/*
10177 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
10178 	 * it's less than ts_recent, drop it.
10179 	 */
10180 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
10181 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
10182 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
10183 			return (ret_val);
10184 	}
10185 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
10186 		return (ret_val);
10187 	}
10188 	/*
10189 	 * If new data are received on a connection after the user processes
10190 	 * are gone, then RST the other end.
10191 	 */
10192 	if ((so->so_state & SS_NOFDREF) &&
10193 	    tlen) {
10194 		if (rack_check_data_after_close(m, tp, &tlen, th, so))
10195 			return (1);
10196 	}
10197 	/*
10198 	 * If last ACK falls within this segment's sequence numbers, record
10199 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
10200 	 * from the latest proposal of the tcplw@cray.com list (Braden
10201 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
10202 	 * with our earlier PAWS tests, so this check should be solely
10203 	 * predicated on the sequence space of this segment. 3) That we
10204 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
10205 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
10206 	 * SEG.Len, This modified check allows us to overcome RFC1323's
10207 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
10208 	 * p.869. In such cases, we can still calculate the RTT correctly
10209 	 * when RCV.NXT == Last.ACK.Sent.
10210 	 */
10211 	if ((to->to_flags & TOF_TS) != 0 &&
10212 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
10213 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
10214 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
10215 		tp->ts_recent_age = tcp_ts_getticks();
10216 		tp->ts_recent = to->to_tsval;
10217 	}
10218 	/*
10219 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
10220 	 * is on (half-synchronized state), then queue data for later
10221 	 * processing; else drop segment and return.
10222 	 */
10223 	if ((thflags & TH_ACK) == 0) {
10224 		if (tp->t_flags & TF_NEEDSYN) {
10225 			return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10226 			    tiwin, thflags, nxt_pkt));
10227 		} else if (tp->t_flags & TF_ACKNOW) {
10228 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
10229 			((struct tcp_rack *)tp->t_fb_ptr)->r_wanted_output = 1;
10230 			return (ret_val);
10231 		} else {
10232 			ctf_do_drop(m, NULL);
10233 			return (0);
10234 		}
10235 	}
10236 	/*
10237 	 * Ack processing.
10238 	 */
10239 	if (rack_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
10240 		return (ret_val);
10241 	}
10242 	if (sbavail(&so->so_snd)) {
10243 		if (ctf_progress_timeout_check(tp, true)) {
10244 			rack_log_progress_event((struct tcp_rack *)tp->t_fb_ptr,
10245 						tp, tick, PROGRESS_DROP, __LINE__);
10246 			tcp_set_inp_to_drop(tp->t_inpcb, ETIMEDOUT);
10247 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
10248 			return (1);
10249 		}
10250 	}
10251 	return (rack_process_data(m, th, so, tp, drop_hdrlen, tlen,
10252 	    tiwin, thflags, nxt_pkt));
10253 }
10254 
10255 static void inline
10256 rack_clear_rate_sample(struct tcp_rack *rack)
10257 {
10258 	rack->r_ctl.rack_rs.rs_flags = RACK_RTT_EMPTY;
10259 	rack->r_ctl.rack_rs.rs_rtt_cnt = 0;
10260 	rack->r_ctl.rack_rs.rs_rtt_tot = 0;
10261 }
10262 
10263 static void
10264 rack_set_pace_segments(struct tcpcb *tp, struct tcp_rack *rack, uint32_t line)
10265 {
10266 	uint64_t bw_est, rate_wanted;
10267 	int chged = 0;
10268 	uint32_t user_max;
10269 
10270 	user_max = ctf_fixed_maxseg(tp) * rack->rc_user_set_max_segs;
10271 	if (ctf_fixed_maxseg(tp) != rack->r_ctl.rc_pace_min_segs)
10272 		chged = 1;
10273 	rack->r_ctl.rc_pace_min_segs = ctf_fixed_maxseg(tp);
10274 	if (rack->use_fixed_rate || rack->rc_force_max_seg) {
10275 		if (user_max != rack->r_ctl.rc_pace_max_segs)
10276 			chged = 1;
10277 	}
10278 	if (rack->rc_force_max_seg) {
10279 		rack->r_ctl.rc_pace_max_segs = user_max;
10280 	} else if (rack->use_fixed_rate) {
10281 		bw_est = rack_get_bw(rack);
10282 		if ((rack->r_ctl.crte == NULL) ||
10283 		    (bw_est != rack->r_ctl.crte->rate))  {
10284 			rack->r_ctl.rc_pace_max_segs = user_max;
10285 		} else {
10286 			/* We are pacing right at the hardware rate */
10287 			uint32_t segsiz;
10288 
10289 			segsiz = min(ctf_fixed_maxseg(tp),
10290 				     rack->r_ctl.rc_pace_min_segs);
10291 			rack->r_ctl.rc_pace_max_segs = tcp_get_pacing_burst_size(
10292 				                           tp, bw_est, segsiz, 0,
10293 							   rack->r_ctl.crte, NULL);
10294 		}
10295 	} else if (rack->rc_always_pace) {
10296 		if (rack->r_ctl.gp_bw ||
10297 #ifdef NETFLIX_PEAKRATE
10298 		    rack->rc_tp->t_maxpeakrate ||
10299 #endif
10300 		    rack->r_ctl.init_rate) {
10301 			/* We have a rate of some sort set */
10302 			uint32_t  orig;
10303 
10304 			bw_est = rack_get_bw(rack);
10305 			orig = rack->r_ctl.rc_pace_max_segs;
10306 			rate_wanted = rack_get_output_bw(rack, bw_est, NULL);
10307 			if (rate_wanted) {
10308 				/* We have something */
10309 				rack->r_ctl.rc_pace_max_segs = rack_get_pacing_len(rack,
10310 										   rate_wanted,
10311 										   ctf_fixed_maxseg(rack->rc_tp));
10312 			} else
10313 				rack->r_ctl.rc_pace_max_segs = rack->r_ctl.rc_pace_min_segs;
10314 			if (orig != rack->r_ctl.rc_pace_max_segs)
10315 				chged = 1;
10316 		} else if ((rack->r_ctl.gp_bw == 0) &&
10317 			   (rack->r_ctl.rc_pace_max_segs == 0)) {
10318 			/*
10319 			 * If we have nothing limit us to bursting
10320 			 * out IW sized pieces.
10321 			 */
10322 			chged = 1;
10323 			rack->r_ctl.rc_pace_max_segs = rc_init_window(rack);
10324 		}
10325 	}
10326 	if (rack->r_ctl.rc_pace_max_segs > PACE_MAX_IP_BYTES) {
10327 		chged = 1;
10328 		rack->r_ctl.rc_pace_max_segs = PACE_MAX_IP_BYTES;
10329 	}
10330 	if (chged)
10331 		rack_log_type_hrdwtso(tp, rack, 0, rack->rc_inp->inp_socket->so_snd.sb_flags, line, 2);
10332 }
10333 
10334 static int
10335 rack_init(struct tcpcb *tp)
10336 {
10337 	struct tcp_rack *rack = NULL;
10338 	struct rack_sendmap *insret;
10339 	uint32_t iwin, snt, us_cts;
10340 
10341 	tp->t_fb_ptr = uma_zalloc(rack_pcb_zone, M_NOWAIT);
10342 	if (tp->t_fb_ptr == NULL) {
10343 		/*
10344 		 * We need to allocate memory but cant. The INP and INP_INFO
10345 		 * locks and they are recusive (happens during setup. So a
10346 		 * scheme to drop the locks fails :(
10347 		 *
10348 		 */
10349 		return (ENOMEM);
10350 	}
10351 	memset(tp->t_fb_ptr, 0, sizeof(struct tcp_rack));
10352 
10353 	rack = (struct tcp_rack *)tp->t_fb_ptr;
10354 	RB_INIT(&rack->r_ctl.rc_mtree);
10355 	TAILQ_INIT(&rack->r_ctl.rc_free);
10356 	TAILQ_INIT(&rack->r_ctl.rc_tmap);
10357 	rack->rc_tp = tp;
10358 	if (tp->t_inpcb) {
10359 		rack->rc_inp = tp->t_inpcb;
10360 	}
10361 	/* Probably not needed but lets be sure */
10362 	rack_clear_rate_sample(rack);
10363 	rack->r_ctl.rc_reorder_fade = rack_reorder_fade;
10364 	rack->rc_allow_data_af_clo = rack_ignore_data_after_close;
10365 	rack->r_ctl.rc_tlp_threshold = rack_tlp_thresh;
10366 	if (use_rack_rr)
10367 		rack->use_rack_rr = 1;
10368 	if (V_tcp_delack_enabled)
10369 		tp->t_delayed_ack = 1;
10370 	else
10371 		tp->t_delayed_ack = 0;
10372 	if (rack_enable_shared_cwnd)
10373 		rack->rack_enable_scwnd = 1;
10374 	rack->rc_user_set_max_segs = rack_hptsi_segments;
10375 	rack->rc_force_max_seg = 0;
10376 	if (rack_use_imac_dack)
10377 		rack->rc_dack_mode = 1;
10378 	rack->r_ctl.rc_reorder_shift = rack_reorder_thresh;
10379 	rack->r_ctl.rc_pkt_delay = rack_pkt_delay;
10380 	rack->r_ctl.rc_prop_reduce = rack_use_proportional_reduce;
10381 	rack->r_ctl.rc_prop_rate = rack_proportional_rate;
10382 	rack->r_ctl.rc_tlp_cwnd_reduce = rack_lower_cwnd_at_tlp;
10383 	rack->r_ctl.rc_early_recovery = rack_early_recovery;
10384 	rack->r_ctl.rc_lowest_us_rtt = 0xffffffff;
10385 	rack->r_ctl.rc_highest_us_rtt = 0;
10386 	if (rack_disable_prr)
10387 		rack->rack_no_prr = 1;
10388 	if (rack_gp_no_rec_chg)
10389 		rack->rc_gp_no_rec_chg = 1;
10390 	rack->rc_always_pace = rack_pace_every_seg;
10391 	if (rack_enable_mqueue_for_nonpaced)
10392 		rack->r_mbuf_queue = 1;
10393 	else
10394 		rack->r_mbuf_queue = 0;
10395 	if  (rack->r_mbuf_queue || rack->rc_always_pace)
10396 		tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
10397 	else
10398 		tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
10399 	rack_set_pace_segments(tp, rack, __LINE__);
10400 	if (rack_limits_scwnd)
10401 		rack->r_limit_scw  = 1;
10402 	else
10403 		rack->r_limit_scw  = 0;
10404 	rack->r_ctl.rc_high_rwnd = tp->snd_wnd;
10405 	rack->r_ctl.cwnd_to_use = tp->snd_cwnd;
10406 	rack->r_ctl.rc_rate_sample_method = rack_rate_sample_method;
10407 	rack->rack_tlp_threshold_use = rack_tlp_threshold_use;
10408 	rack->r_ctl.rc_prr_sendalot = rack_send_a_lot_in_prr;
10409 	rack->r_ctl.rc_min_to = rack_min_to;
10410 	microuptime(&rack->r_ctl.act_rcv_time);
10411 	rack->r_ctl.rc_last_time_decay = rack->r_ctl.act_rcv_time;
10412 	rack->r_running_late = 0;
10413 	rack->r_running_early = 0;
10414 	rack->rc_init_win = rack_default_init_window;
10415 	rack->r_ctl.rack_per_of_gp_ss = rack_per_of_gp_ss;
10416 	if (rack_do_dyn_mul) {
10417 		/* When dynamic adjustment is on CA needs to start at 100% */
10418 		rack->rc_gp_dyn_mul = 1;
10419 		if (rack_do_dyn_mul >= 100)
10420 			rack->r_ctl.rack_per_of_gp_ca = rack_do_dyn_mul;
10421 	} else
10422 		rack->r_ctl.rack_per_of_gp_ca = rack_per_of_gp_ca;
10423 	rack->r_ctl.rack_per_of_gp_rec = rack_per_of_gp_rec;
10424 	rack->r_ctl.rack_per_of_gp_probertt = rack_per_of_gp_probertt;
10425 	rack->r_ctl.rc_tlp_rxt_last_time = tcp_tv_to_mssectick(&rack->r_ctl.act_rcv_time);
10426 	setup_time_filter_small(&rack->r_ctl.rc_gp_min_rtt, FILTER_TYPE_MIN,
10427 				rack_probertt_filter_life);
10428 	us_cts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
10429 	rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
10430 	rack->r_ctl.rc_time_of_last_probertt = us_cts;
10431 	rack->r_ctl.rc_time_probertt_starts = 0;
10432 	/* Do we force on detection? */
10433 #ifdef NETFLIX_EXP_DETECTION
10434 	if (tcp_force_detection)
10435 		rack->do_detection = 1;
10436 	else
10437 #endif
10438 		rack->do_detection = 0;
10439 	if (rack_non_rxt_use_cr)
10440 		rack->rack_rec_nonrxt_use_cr = 1;
10441 	if (tp->snd_una != tp->snd_max) {
10442 		/* Create a send map for the current outstanding data */
10443 		struct rack_sendmap *rsm;
10444 
10445 		rsm = rack_alloc(rack);
10446 		if (rsm == NULL) {
10447 			uma_zfree(rack_pcb_zone, tp->t_fb_ptr);
10448 			tp->t_fb_ptr = NULL;
10449 			return (ENOMEM);
10450 		}
10451 		rsm->r_flags = RACK_OVERMAX;
10452 		rsm->r_tim_lastsent[0] = rack->r_ctl.rc_tlp_rxt_last_time;
10453 		rsm->r_rtr_cnt = 1;
10454 		rsm->r_rtr_bytes = 0;
10455 		rsm->r_start = tp->snd_una;
10456 		if (tp->t_flags & TF_SENTFIN) {
10457 			rsm->r_end = tp->snd_max - 1;
10458 			rsm->r_flags |= RACK_HAS_FIN;
10459 		} else {
10460 			rsm->r_end = tp->snd_max;
10461 		}
10462 		rsm->usec_orig_send = us_cts;
10463 		rsm->r_dupack = 0;
10464 		insret = RB_INSERT(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
10465 #ifdef INVARIANTS
10466 		if (insret != NULL) {
10467 			panic("Insert in rb tree fails ret:%p rack:%p rsm:%p",
10468 			      insret, rack, rsm);
10469 		}
10470 #endif
10471 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_tmap, rsm, r_tnext);
10472 		rsm->r_in_tmap = 1;
10473 	}
10474 	/* Cancel the GP measurement in progress */
10475 	tp->t_flags &= ~TF_GPUTINPROG;
10476 	if (SEQ_GT(tp->snd_max, tp->iss))
10477 		snt = tp->snd_max - tp->iss;
10478 	else
10479 		snt = 0;
10480 	iwin = rc_init_window(rack);
10481 	if (snt < iwin) {
10482 		/* We are not past the initial window
10483 		 * so we need to make sure cwnd is
10484 		 * correct.
10485 		 */
10486 		if (tp->snd_cwnd < iwin)
10487 			tp->snd_cwnd = iwin;
10488 		/*
10489 		 * If we are within the initial window
10490 		 * we want ssthresh to be unlimited. Setting
10491 		 * it to the rwnd (which the default stack does
10492 		 * and older racks) is not really a good idea
10493 		 * since we want to be in SS and grow both the
10494 		 * cwnd and the rwnd (via dynamic rwnd growth). If
10495 		 * we set it to the rwnd then as the peer grows its
10496 		 * rwnd we will be stuck in CA and never hit SS.
10497 		 *
10498 		 * Its far better to raise it up high (this takes the
10499 		 * risk that there as been a loss already, probably
10500 		 * we should have an indicator in all stacks of loss
10501 		 * but we don't), but considering the normal use this
10502 		 * is a risk worth taking. The consequences of not
10503 		 * hitting SS are far worse than going one more time
10504 		 * into it early on (before we have sent even a IW).
10505 		 * It is highly unlikely that we will have had a loss
10506 		 * before getting the IW out.
10507 		 */
10508 		tp->snd_ssthresh = 0xffffffff;
10509 	}
10510 	rack_stop_all_timers(tp);
10511 	rack_start_hpts_timer(rack, tp, tcp_ts_getticks(), 0, 0, 0);
10512 	rack_log_rtt_shrinks(rack,  us_cts,  0,
10513 			     __LINE__, RACK_RTTS_INIT);
10514 	return (0);
10515 }
10516 
10517 static int
10518 rack_handoff_ok(struct tcpcb *tp)
10519 {
10520 	if ((tp->t_state == TCPS_CLOSED) ||
10521 	    (tp->t_state == TCPS_LISTEN)) {
10522 		/* Sure no problem though it may not stick */
10523 		return (0);
10524 	}
10525 	if ((tp->t_state == TCPS_SYN_SENT) ||
10526 	    (tp->t_state == TCPS_SYN_RECEIVED)) {
10527 		/*
10528 		 * We really don't know if you support sack,
10529 		 * you have to get to ESTAB or beyond to tell.
10530 		 */
10531 		return (EAGAIN);
10532 	}
10533 	if ((tp->t_flags & TF_SENTFIN) && ((tp->snd_max - tp->snd_una) > 1)) {
10534 		/*
10535 		 * Rack will only send a FIN after all data is acknowledged.
10536 		 * So in this case we have more data outstanding. We can't
10537 		 * switch stacks until either all data and only the FIN
10538 		 * is left (in which case rack_init() now knows how
10539 		 * to deal with that) <or> all is acknowledged and we
10540 		 * are only left with incoming data, though why you
10541 		 * would want to switch to rack after all data is acknowledged
10542 		 * I have no idea (rrs)!
10543 		 */
10544 		return (EAGAIN);
10545 	}
10546 	if ((tp->t_flags & TF_SACK_PERMIT) || rack_sack_not_required){
10547 		return (0);
10548 	}
10549 	/*
10550 	 * If we reach here we don't do SACK on this connection so we can
10551 	 * never do rack.
10552 	 */
10553 	return (EINVAL);
10554 }
10555 
10556 static void
10557 rack_fini(struct tcpcb *tp, int32_t tcb_is_purged)
10558 {
10559 	if (tp->t_fb_ptr) {
10560 		struct tcp_rack *rack;
10561 		struct rack_sendmap *rsm, *nrsm, *rm;
10562 
10563 		rack = (struct tcp_rack *)tp->t_fb_ptr;
10564 #ifdef NETFLIX_SHARED_CWND
10565 		if (rack->r_ctl.rc_scw) {
10566 			uint32_t limit;
10567 
10568 			if (rack->r_limit_scw)
10569 				limit = max(1, rack->r_ctl.rc_lowest_us_rtt);
10570 			else
10571 				limit = 0;
10572 			tcp_shared_cwnd_free_full(tp, rack->r_ctl.rc_scw,
10573 						  rack->r_ctl.rc_scw_index,
10574 						  limit);
10575 			rack->r_ctl.rc_scw = NULL;
10576 		}
10577 #endif
10578 		/* rack does not use force data but other stacks may clear it */
10579 		tp->t_flags &= ~TF_FORCEDATA;
10580 		if (tp->t_inpcb) {
10581 			tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
10582 			tp->t_inpcb->inp_flags2 &= ~INP_MBUF_QUEUE_READY;
10583 			tp->t_inpcb->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
10584 		}
10585 #ifdef TCP_BLACKBOX
10586 		tcp_log_flowend(tp);
10587 #endif
10588 		RB_FOREACH_SAFE(rsm, rack_rb_tree_head, &rack->r_ctl.rc_mtree, nrsm) {
10589 			rm = RB_REMOVE(rack_rb_tree_head, &rack->r_ctl.rc_mtree, rsm);
10590 #ifdef INVARIANTS
10591 			if (rm != rsm) {
10592 				panic("At fini, rack:%p rsm:%p rm:%p",
10593 				      rack, rsm, rm);
10594 			}
10595 #endif
10596 			uma_zfree(rack_zone, rsm);
10597 		}
10598 		rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
10599 		while (rsm) {
10600 			TAILQ_REMOVE(&rack->r_ctl.rc_free, rsm, r_tnext);
10601 			uma_zfree(rack_zone, rsm);
10602 			rsm = TAILQ_FIRST(&rack->r_ctl.rc_free);
10603 		}
10604 		rack->rc_free_cnt = 0;
10605 		uma_zfree(rack_pcb_zone, tp->t_fb_ptr);
10606 		tp->t_fb_ptr = NULL;
10607 	}
10608 	/* Cancel the GP measurement in progress */
10609 	tp->t_flags &= ~TF_GPUTINPROG;
10610 	/* Make sure snd_nxt is correctly set */
10611 	tp->snd_nxt = tp->snd_max;
10612 }
10613 
10614 static void
10615 rack_set_state(struct tcpcb *tp, struct tcp_rack *rack)
10616 {
10617 	switch (tp->t_state) {
10618 	case TCPS_SYN_SENT:
10619 		rack->r_state = TCPS_SYN_SENT;
10620 		rack->r_substate = rack_do_syn_sent;
10621 		break;
10622 	case TCPS_SYN_RECEIVED:
10623 		rack->r_state = TCPS_SYN_RECEIVED;
10624 		rack->r_substate = rack_do_syn_recv;
10625 		break;
10626 	case TCPS_ESTABLISHED:
10627 		rack_set_pace_segments(tp, rack, __LINE__);
10628 		rack->r_state = TCPS_ESTABLISHED;
10629 		rack->r_substate = rack_do_established;
10630 		break;
10631 	case TCPS_CLOSE_WAIT:
10632 		rack->r_state = TCPS_CLOSE_WAIT;
10633 		rack->r_substate = rack_do_close_wait;
10634 		break;
10635 	case TCPS_FIN_WAIT_1:
10636 		rack->r_state = TCPS_FIN_WAIT_1;
10637 		rack->r_substate = rack_do_fin_wait_1;
10638 		break;
10639 	case TCPS_CLOSING:
10640 		rack->r_state = TCPS_CLOSING;
10641 		rack->r_substate = rack_do_closing;
10642 		break;
10643 	case TCPS_LAST_ACK:
10644 		rack->r_state = TCPS_LAST_ACK;
10645 		rack->r_substate = rack_do_lastack;
10646 		break;
10647 	case TCPS_FIN_WAIT_2:
10648 		rack->r_state = TCPS_FIN_WAIT_2;
10649 		rack->r_substate = rack_do_fin_wait_2;
10650 		break;
10651 	case TCPS_LISTEN:
10652 	case TCPS_CLOSED:
10653 	case TCPS_TIME_WAIT:
10654 	default:
10655 		break;
10656 	};
10657 }
10658 
10659 static void
10660 rack_timer_audit(struct tcpcb *tp, struct tcp_rack *rack, struct sockbuf *sb)
10661 {
10662 	/*
10663 	 * We received an ack, and then did not
10664 	 * call send or were bounced out due to the
10665 	 * hpts was running. Now a timer is up as well, is
10666 	 * it the right timer?
10667 	 */
10668 	struct rack_sendmap *rsm;
10669 	int tmr_up;
10670 
10671 	tmr_up = rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK;
10672 	if (rack->rc_in_persist && (tmr_up == PACE_TMR_PERSIT))
10673 		return;
10674 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
10675 	if (((rsm == NULL) || (tp->t_state < TCPS_ESTABLISHED)) &&
10676 	    (tmr_up == PACE_TMR_RXT)) {
10677 		/* Should be an RXT */
10678 		return;
10679 	}
10680 	if (rsm == NULL) {
10681 		/* Nothing outstanding? */
10682 		if (tp->t_flags & TF_DELACK) {
10683 			if (tmr_up == PACE_TMR_DELACK)
10684 				/* We are supposed to have delayed ack up and we do */
10685 				return;
10686 		} else if (sbavail(&tp->t_inpcb->inp_socket->so_snd) && (tmr_up == PACE_TMR_RXT)) {
10687 			/*
10688 			 * if we hit enobufs then we would expect the possiblity
10689 			 * of nothing outstanding and the RXT up (and the hptsi timer).
10690 			 */
10691 			return;
10692 		} else if (((V_tcp_always_keepalive ||
10693 			     rack->rc_inp->inp_socket->so_options & SO_KEEPALIVE) &&
10694 			    (tp->t_state <= TCPS_CLOSING)) &&
10695 			   (tmr_up == PACE_TMR_KEEP) &&
10696 			   (tp->snd_max == tp->snd_una)) {
10697 			/* We should have keep alive up and we do */
10698 			return;
10699 		}
10700 	}
10701 	if (SEQ_GT(tp->snd_max, tp->snd_una) &&
10702 		   ((tmr_up == PACE_TMR_TLP) ||
10703 		    (tmr_up == PACE_TMR_RACK) ||
10704 		    (tmr_up == PACE_TMR_RXT))) {
10705 		/*
10706 		 * Either a Rack, TLP or RXT is fine if  we
10707 		 * have outstanding data.
10708 		 */
10709 		return;
10710 	} else if (tmr_up == PACE_TMR_DELACK) {
10711 		/*
10712 		 * If the delayed ack was going to go off
10713 		 * before the rtx/tlp/rack timer were going to
10714 		 * expire, then that would be the timer in control.
10715 		 * Note we don't check the time here trusting the
10716 		 * code is correct.
10717 		 */
10718 		return;
10719 	}
10720 	/*
10721 	 * Ok the timer originally started is not what we want now.
10722 	 * We will force the hpts to be stopped if any, and restart
10723 	 * with the slot set to what was in the saved slot.
10724 	 */
10725 	if (rack->rc_inp->inp_in_hpts) {
10726 		if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
10727 			uint32_t us_cts;
10728 
10729 			us_cts = tcp_get_usecs(NULL);
10730 			if (TSTMP_GT(rack->r_ctl.rc_last_output_to, us_cts)) {
10731 				rack->r_early = 1;
10732 				rack->r_ctl.rc_agg_early += (rack->r_ctl.rc_last_output_to - us_cts);
10733 			}
10734 			rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
10735 		}
10736 		tcp_hpts_remove(tp->t_inpcb, HPTS_REMOVE_OUTPUT);
10737 	}
10738 	rack_timer_cancel(tp, rack, rack->r_ctl.rc_rcvtime, __LINE__);
10739 	rack_start_hpts_timer(rack, tp, tcp_ts_getticks(), 0, 0, 0);
10740 }
10741 
10742 static int
10743 rack_do_segment_nounlock(struct mbuf *m, struct tcphdr *th, struct socket *so,
10744     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos,
10745     int32_t nxt_pkt, struct timeval *tv)
10746 {
10747 	int32_t thflags, retval, did_out = 0;
10748 	int32_t way_out = 0;
10749 	uint32_t cts;
10750 	uint32_t tiwin;
10751 	struct timespec ts;
10752 	struct tcpopt to;
10753 	struct tcp_rack *rack;
10754 	struct rack_sendmap *rsm;
10755 	int32_t prev_state = 0;
10756 	uint32_t us_cts;
10757 	/*
10758 	 * tv passed from common code is from either M_TSTMP_LRO or
10759 	 * tcp_get_usecs() if no LRO m_pkthdr timestamp is present. The
10760 	 * rack_pacing stack assumes tv always refers to 'now', so we overwrite
10761 	 * tv here to guarantee that.
10762 	 */
10763 	if (m->m_flags & M_TSTMP_LRO)
10764 		tcp_get_usecs(tv);
10765 
10766 	cts = tcp_tv_to_mssectick(tv);
10767 	rack = (struct tcp_rack *)tp->t_fb_ptr;
10768 
10769 	if ((m->m_flags & M_TSTMP) ||
10770 	    (m->m_flags & M_TSTMP_LRO)) {
10771 		mbuf_tstmp2timespec(m, &ts);
10772 		rack->r_ctl.act_rcv_time.tv_sec = ts.tv_sec;
10773 		rack->r_ctl.act_rcv_time.tv_usec = ts.tv_nsec/1000;
10774 	} else
10775 		rack->r_ctl.act_rcv_time = *tv;
10776 	kern_prefetch(rack, &prev_state);
10777 	prev_state = 0;
10778 	thflags = th->th_flags;
10779 
10780 	NET_EPOCH_ASSERT();
10781 	INP_WLOCK_ASSERT(tp->t_inpcb);
10782 	KASSERT(tp->t_state > TCPS_LISTEN, ("%s: TCPS_LISTEN",
10783 	    __func__));
10784 	KASSERT(tp->t_state != TCPS_TIME_WAIT, ("%s: TCPS_TIME_WAIT",
10785 	    __func__));
10786 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
10787 		union tcp_log_stackspecific log;
10788 		struct timeval ltv;
10789 #ifdef NETFLIX_HTTP_LOGGING
10790 		struct http_sendfile_track *http_req;
10791 
10792 		if (SEQ_GT(th->th_ack, tp->snd_una)) {
10793 			http_req = tcp_http_find_req_for_seq(tp, (th->th_ack-1));
10794 		} else {
10795 			http_req = tcp_http_find_req_for_seq(tp, th->th_ack);
10796 		}
10797 #endif
10798 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
10799 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
10800 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
10801 		if (rack->rack_no_prr == 0)
10802 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
10803 		else
10804 			log.u_bbr.flex1 = 0;
10805 		log.u_bbr.flex2 = rack->r_ctl.rc_num_maps_alloced;
10806 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
10807 		log.u_bbr.pkts_out = rack->rc_tp->t_maxseg;
10808 		log.u_bbr.flex3 = m->m_flags;
10809 		log.u_bbr.flex4 = rack->r_ctl.rc_hpts_flags;
10810 		if (m->m_flags & M_TSTMP) {
10811 			/* Record the hardware timestamp if present */
10812 			mbuf_tstmp2timespec(m, &ts);
10813 			ltv.tv_sec = ts.tv_sec;
10814 			ltv.tv_usec = ts.tv_nsec / 1000;
10815 			log.u_bbr.lt_epoch = tcp_tv_to_usectick(&ltv);
10816 		} else if (m->m_flags & M_TSTMP_LRO) {
10817 			/* Record the LRO the arrival timestamp */
10818 			mbuf_tstmp2timespec(m, &ts);
10819 			ltv.tv_sec = ts.tv_sec;
10820 			ltv.tv_usec = ts.tv_nsec / 1000;
10821 			log.u_bbr.flex5 = tcp_tv_to_usectick(&ltv);
10822 		}
10823 		log.u_bbr.timeStamp = tcp_get_usecs(&ltv);
10824 		/* Log the rcv time */
10825 		log.u_bbr.delRate = m->m_pkthdr.rcv_tstmp;
10826 #ifdef NETFLIX_HTTP_LOGGING
10827 		log.u_bbr.applimited = tp->t_http_closed;
10828 		log.u_bbr.applimited <<= 8;
10829 		log.u_bbr.applimited |= tp->t_http_open;
10830 		log.u_bbr.applimited <<= 8;
10831 		log.u_bbr.applimited |= tp->t_http_req;
10832 		if (http_req) {
10833 			/* Copy out any client req info */
10834 			/* seconds */
10835 			log.u_bbr.pkt_epoch = (http_req->localtime / HPTS_USEC_IN_SEC);
10836 			/* useconds */
10837 			log.u_bbr.delivered = (http_req->localtime % HPTS_USEC_IN_SEC);
10838 			log.u_bbr.rttProp = http_req->timestamp;
10839 			log.u_bbr.cur_del_rate = http_req->start;
10840 			if (http_req->flags & TCP_HTTP_TRACK_FLG_OPEN) {
10841 				log.u_bbr.flex8 |= 1;
10842 			} else {
10843 				log.u_bbr.flex8 |= 2;
10844 				log.u_bbr.bw_inuse = http_req->end;
10845 			}
10846 			log.u_bbr.flex6 = http_req->start_seq;
10847 			if (http_req->flags & TCP_HTTP_TRACK_FLG_COMP) {
10848 				log.u_bbr.flex8 |= 4;
10849 				log.u_bbr.epoch = http_req->end_seq;
10850 			}
10851 		}
10852 #endif
10853 		TCP_LOG_EVENTP(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_IN, 0,
10854 		    tlen, &log, true, &ltv);
10855 	}
10856 	if ((thflags & TH_SYN) && (thflags & TH_FIN) && V_drop_synfin) {
10857 		way_out = 4;
10858 		retval = 0;
10859 		goto done_with_input;
10860 	}
10861 	/*
10862 	 * If a segment with the ACK-bit set arrives in the SYN-SENT state
10863 	 * check SEQ.ACK first as described on page 66 of RFC 793, section 3.9.
10864 	 */
10865 	if ((tp->t_state == TCPS_SYN_SENT) && (thflags & TH_ACK) &&
10866 	    (SEQ_LEQ(th->th_ack, tp->iss) || SEQ_GT(th->th_ack, tp->snd_max))) {
10867 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
10868 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
10869 		return(1);
10870 	}
10871 
10872 	/*
10873 	 * Parse options on any incoming segment.
10874 	 */
10875 	tcp_dooptions(&to, (u_char *)(th + 1),
10876 	    (th->th_off << 2) - sizeof(struct tcphdr),
10877 	    (thflags & TH_SYN) ? TO_SYN : 0);
10878 
10879 	/*
10880 	 * If timestamps were negotiated during SYN/ACK and a
10881 	 * segment without a timestamp is received, silently drop
10882 	 * the segment, unless it is a RST segment or missing timestamps are
10883 	 * tolerated.
10884 	 * See section 3.2 of RFC 7323.
10885 	 */
10886 	if ((tp->t_flags & TF_RCVD_TSTMP) && !(to.to_flags & TOF_TS) &&
10887 	    ((thflags & TH_RST) == 0) && (V_tcp_tolerate_missing_ts == 0)) {
10888 		way_out = 5;
10889 		retval = 0;
10890 		goto done_with_input;
10891 	}
10892 
10893 	/*
10894 	 * Segment received on connection. Reset idle time and keep-alive
10895 	 * timer. XXX: This should be done after segment validation to
10896 	 * ignore broken/spoofed segs.
10897 	 */
10898 	if  (tp->t_idle_reduce &&
10899 	     (tp->snd_max == tp->snd_una) &&
10900 	     ((ticks - tp->t_rcvtime) >= tp->t_rxtcur)) {
10901 		counter_u64_add(rack_input_idle_reduces, 1);
10902 		rack_cc_after_idle(rack, tp);
10903 	}
10904 	tp->t_rcvtime = ticks;
10905 	/*
10906 	 * Unscale the window into a 32-bit value. For the SYN_SENT state
10907 	 * the scale is zero.
10908 	 */
10909 	tiwin = th->th_win << tp->snd_scale;
10910 #ifdef STATS
10911 	stats_voi_update_abs_ulong(tp->t_stats, VOI_TCP_FRWIN, tiwin);
10912 #endif
10913 	if (tiwin > rack->r_ctl.rc_high_rwnd)
10914 		rack->r_ctl.rc_high_rwnd = tiwin;
10915 	/*
10916 	 * TCP ECN processing. XXXJTL: If we ever use ECN, we need to move
10917 	 * this to occur after we've validated the segment.
10918 	 */
10919 	if (tp->t_flags2 & TF2_ECN_PERMIT) {
10920 		if (thflags & TH_CWR) {
10921 			tp->t_flags2 &= ~TF2_ECN_SND_ECE;
10922 			tp->t_flags |= TF_ACKNOW;
10923 		}
10924 		switch (iptos & IPTOS_ECN_MASK) {
10925 		case IPTOS_ECN_CE:
10926 			tp->t_flags2 |= TF2_ECN_SND_ECE;
10927 			KMOD_TCPSTAT_INC(tcps_ecn_ce);
10928 			break;
10929 		case IPTOS_ECN_ECT0:
10930 			KMOD_TCPSTAT_INC(tcps_ecn_ect0);
10931 			break;
10932 		case IPTOS_ECN_ECT1:
10933 			KMOD_TCPSTAT_INC(tcps_ecn_ect1);
10934 			break;
10935 		}
10936 
10937 		/* Process a packet differently from RFC3168. */
10938 		cc_ecnpkt_handler(tp, th, iptos);
10939 
10940 		/* Congestion experienced. */
10941 		if (thflags & TH_ECE) {
10942 			rack_cong_signal(tp, th, CC_ECN);
10943 		}
10944 	}
10945 
10946 	/*
10947 	 * If echoed timestamp is later than the current time, fall back to
10948 	 * non RFC1323 RTT calculation.  Normalize timestamp if syncookies
10949 	 * were used when this connection was established.
10950 	 */
10951 	if ((to.to_flags & TOF_TS) && (to.to_tsecr != 0)) {
10952 		to.to_tsecr -= tp->ts_offset;
10953 		if (TSTMP_GT(to.to_tsecr, cts))
10954 			to.to_tsecr = 0;
10955 	}
10956 
10957 	/*
10958 	 * If its the first time in we need to take care of options and
10959 	 * verify we can do SACK for rack!
10960 	 */
10961 	if (rack->r_state == 0) {
10962 		/* Should be init'd by rack_init() */
10963 		KASSERT(rack->rc_inp != NULL,
10964 		    ("%s: rack->rc_inp unexpectedly NULL", __func__));
10965 		if (rack->rc_inp == NULL) {
10966 			rack->rc_inp = tp->t_inpcb;
10967 		}
10968 
10969 		/*
10970 		 * Process options only when we get SYN/ACK back. The SYN
10971 		 * case for incoming connections is handled in tcp_syncache.
10972 		 * According to RFC1323 the window field in a SYN (i.e., a
10973 		 * <SYN> or <SYN,ACK>) segment itself is never scaled. XXX
10974 		 * this is traditional behavior, may need to be cleaned up.
10975 		 */
10976 		if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) {
10977 			/* Handle parallel SYN for ECN */
10978 			if (!(thflags & TH_ACK) &&
10979 			    ((thflags & (TH_CWR | TH_ECE)) == (TH_CWR | TH_ECE)) &&
10980 			    ((V_tcp_do_ecn == 1) || (V_tcp_do_ecn == 2))) {
10981 				tp->t_flags2 |= TF2_ECN_PERMIT;
10982 				tp->t_flags2 |= TF2_ECN_SND_ECE;
10983 				TCPSTAT_INC(tcps_ecn_shs);
10984 			}
10985 			if ((to.to_flags & TOF_SCALE) &&
10986 			    (tp->t_flags & TF_REQ_SCALE)) {
10987 				tp->t_flags |= TF_RCVD_SCALE;
10988 				tp->snd_scale = to.to_wscale;
10989 			} else
10990 				tp->t_flags &= ~TF_REQ_SCALE;
10991 			/*
10992 			 * Initial send window.  It will be updated with the
10993 			 * next incoming segment to the scaled value.
10994 			 */
10995 			tp->snd_wnd = th->th_win;
10996 			if ((to.to_flags & TOF_TS) &&
10997 			    (tp->t_flags & TF_REQ_TSTMP)) {
10998 				tp->t_flags |= TF_RCVD_TSTMP;
10999 				tp->ts_recent = to.to_tsval;
11000 				tp->ts_recent_age = cts;
11001 			} else
11002 				tp->t_flags &= ~TF_REQ_TSTMP;
11003 			if (to.to_flags & TOF_MSS)
11004 				tcp_mss(tp, to.to_mss);
11005 			if ((tp->t_flags & TF_SACK_PERMIT) &&
11006 			    (to.to_flags & TOF_SACKPERM) == 0)
11007 				tp->t_flags &= ~TF_SACK_PERMIT;
11008 			if (IS_FASTOPEN(tp->t_flags)) {
11009 				if (to.to_flags & TOF_FASTOPEN) {
11010 					uint16_t mss;
11011 
11012 					if (to.to_flags & TOF_MSS)
11013 						mss = to.to_mss;
11014 					else
11015 						if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
11016 							mss = TCP6_MSS;
11017 						else
11018 							mss = TCP_MSS;
11019 					tcp_fastopen_update_cache(tp, mss,
11020 					    to.to_tfo_len, to.to_tfo_cookie);
11021 				} else
11022 					tcp_fastopen_disable_path(tp);
11023 			}
11024 		}
11025 		/*
11026 		 * At this point we are at the initial call. Here we decide
11027 		 * if we are doing RACK or not. We do this by seeing if
11028 		 * TF_SACK_PERMIT is set and the sack-not-required is clear.
11029 		 * The code now does do dup-ack counting so if you don't
11030 		 * switch back you won't get rack & TLP, but you will still
11031 		 * get this stack.
11032 		 */
11033 
11034 		if ((rack_sack_not_required == 0) &&
11035 		    ((tp->t_flags & TF_SACK_PERMIT) == 0)) {
11036 			tcp_switch_back_to_default(tp);
11037 			(*tp->t_fb->tfb_tcp_do_segment) (m, th, so, tp, drop_hdrlen,
11038 			    tlen, iptos);
11039 			return (1);
11040 		}
11041 		/* Set the flag */
11042 		rack->r_is_v6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0;
11043 		tcp_set_hpts(tp->t_inpcb);
11044 		sack_filter_clear(&rack->r_ctl.rack_sf, th->th_ack);
11045 	}
11046 	if (thflags & TH_FIN)
11047 		tcp_log_end_status(tp, TCP_EI_STATUS_CLIENT_FIN);
11048 	us_cts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
11049 	if ((rack->rc_gp_dyn_mul) &&
11050 	    (rack->use_fixed_rate == 0) &&
11051 	    (rack->rc_always_pace)) {
11052 		/* Check in on probertt */
11053 		rack_check_probe_rtt(rack, us_cts);
11054 	}
11055 	if (rack->forced_ack) {
11056 		uint32_t us_rtt;
11057 
11058 		/*
11059 		 * A persist or keep-alive was forced out, update our
11060 		 * min rtt time. Note we do not worry about lost
11061 		 * retransmissions since KEEP-ALIVES and persists
11062 		 * are usually way long on times of sending (though
11063 		 * if we were really paranoid or worried we could
11064 		 * at least use timestamps if available to validate).
11065 		 */
11066 		rack->forced_ack = 0;
11067 		us_rtt = us_cts - rack->r_ctl.forced_ack_ts;
11068 		if (us_rtt == 0)
11069 			us_rtt = 1;
11070 		rack_log_rtt_upd(tp, rack, us_rtt, 0, NULL, 3);
11071 		rack_apply_updated_usrtt(rack, us_rtt, us_cts);
11072 	}
11073 	/*
11074 	 * This is the one exception case where we set the rack state
11075 	 * always. All other times (timers etc) we must have a rack-state
11076 	 * set (so we assure we have done the checks above for SACK).
11077 	 */
11078 	rack->r_ctl.rc_rcvtime = cts;
11079 	if (rack->r_state != tp->t_state)
11080 		rack_set_state(tp, rack);
11081 	if (SEQ_GT(th->th_ack, tp->snd_una) &&
11082 	    (rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree)) != NULL)
11083 		kern_prefetch(rsm, &prev_state);
11084 	prev_state = rack->r_state;
11085 	rack_clear_rate_sample(rack);
11086 	retval = (*rack->r_substate) (m, th, so,
11087 	    tp, &to, drop_hdrlen,
11088 	    tlen, tiwin, thflags, nxt_pkt, iptos);
11089 #ifdef INVARIANTS
11090 	if ((retval == 0) &&
11091 	    (tp->t_inpcb == NULL)) {
11092 		panic("retval:%d tp:%p t_inpcb:NULL state:%d",
11093 		    retval, tp, prev_state);
11094 	}
11095 #endif
11096 	if (retval == 0) {
11097 		/*
11098 		 * If retval is 1 the tcb is unlocked and most likely the tp
11099 		 * is gone.
11100 		 */
11101 		INP_WLOCK_ASSERT(tp->t_inpcb);
11102 		if ((rack->rc_gp_dyn_mul) &&
11103 		    (rack->rc_always_pace) &&
11104 		    (rack->use_fixed_rate == 0) &&
11105 		    rack->in_probe_rtt &&
11106 		    (rack->r_ctl.rc_time_probertt_starts == 0)) {
11107 			/*
11108 			 * If we are going for target, lets recheck before
11109 			 * we output.
11110 			 */
11111 			rack_check_probe_rtt(rack, us_cts);
11112 		}
11113 		if (rack->set_pacing_done_a_iw == 0) {
11114 			/* How much has been acked? */
11115 			if ((tp->snd_una - tp->iss) > (ctf_fixed_maxseg(tp) * 10)) {
11116 				/* We have enough to set in the pacing segment size */
11117 				rack->set_pacing_done_a_iw = 1;
11118 				rack_set_pace_segments(tp, rack, __LINE__);
11119 			}
11120 		}
11121 		tcp_rack_xmit_timer_commit(rack, tp);
11122 		if (nxt_pkt == 0) {
11123 			if (rack->r_wanted_output != 0) {
11124 do_output_now:
11125 				did_out = 1;
11126 				(void)tp->t_fb->tfb_tcp_output(tp);
11127 			}
11128 			rack_start_hpts_timer(rack, tp, cts, 0, 0, 0);
11129 		}
11130 		if ((nxt_pkt == 0) &&
11131 		    ((rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) == 0) &&
11132 		    (SEQ_GT(tp->snd_max, tp->snd_una) ||
11133 		     (tp->t_flags & TF_DELACK) ||
11134 		     ((V_tcp_always_keepalive || rack->rc_inp->inp_socket->so_options & SO_KEEPALIVE) &&
11135 		      (tp->t_state <= TCPS_CLOSING)))) {
11136 			/* We could not send (probably in the hpts but stopped the timer earlier)? */
11137 			if ((tp->snd_max == tp->snd_una) &&
11138 			    ((tp->t_flags & TF_DELACK) == 0) &&
11139 			    (rack->rc_inp->inp_in_hpts) &&
11140 			    (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
11141 				/* keep alive not needed if we are hptsi output yet */
11142 				;
11143 			} else {
11144 				int late = 0;
11145 				if (rack->rc_inp->inp_in_hpts) {
11146 					if (rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
11147 						us_cts = tcp_get_usecs(NULL);
11148 						if (TSTMP_GT(rack->r_ctl.rc_last_output_to, us_cts)) {
11149 							rack->r_early = 1;
11150 							rack->r_ctl.rc_agg_early += (rack->r_ctl.rc_last_output_to - us_cts);
11151 						} else
11152 							late = 1;
11153 						rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
11154 					}
11155 					tcp_hpts_remove(tp->t_inpcb, HPTS_REMOVE_OUTPUT);
11156 				}
11157 				if (late && (did_out == 0)) {
11158 					/*
11159 					 * We are late in the sending
11160 					 * and we did not call the output
11161 					 * (this probably should not happen).
11162 					 */
11163 					goto do_output_now;
11164 				}
11165 				rack_start_hpts_timer(rack, tp, tcp_ts_getticks(), 0, 0, 0);
11166 			}
11167 			way_out = 1;
11168 		} else if (nxt_pkt == 0) {
11169 			/* Do we have the correct timer running? */
11170 			rack_timer_audit(tp, rack, &so->so_snd);
11171 			way_out = 2;
11172 		}
11173 	done_with_input:
11174 		rack_log_doseg_done(rack, cts, nxt_pkt, did_out, way_out);
11175 		if (did_out)
11176 			rack->r_wanted_output = 0;
11177 #ifdef INVARIANTS
11178 		if (tp->t_inpcb == NULL) {
11179 			panic("OP:%d retval:%d tp:%p t_inpcb:NULL state:%d",
11180 			      did_out,
11181 			      retval, tp, prev_state);
11182 		}
11183 #endif
11184 	}
11185 	return (retval);
11186 }
11187 
11188 void
11189 rack_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
11190     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos)
11191 {
11192 	struct timeval tv;
11193 
11194 	/* First lets see if we have old packets */
11195 	if (tp->t_in_pkt) {
11196 		if (ctf_do_queued_segments(so, tp, 1)) {
11197 			m_freem(m);
11198 			return;
11199 		}
11200 	}
11201 	if (m->m_flags & M_TSTMP_LRO) {
11202 		tv.tv_sec = m->m_pkthdr.rcv_tstmp /1000000000;
11203 		tv.tv_usec = (m->m_pkthdr.rcv_tstmp % 1000000000)/1000;
11204 	} else {
11205 		/* Should not be should we kassert instead? */
11206 		tcp_get_usecs(&tv);
11207 	}
11208 	if(rack_do_segment_nounlock(m, th, so, tp,
11209 				    drop_hdrlen, tlen, iptos, 0, &tv) == 0) {
11210 		tcp_handle_wakeup(tp, so);
11211 		INP_WUNLOCK(tp->t_inpcb);
11212 	}
11213 }
11214 
11215 struct rack_sendmap *
11216 tcp_rack_output(struct tcpcb *tp, struct tcp_rack *rack, uint32_t tsused)
11217 {
11218 	struct rack_sendmap *rsm = NULL;
11219 	int32_t idx;
11220 	uint32_t srtt = 0, thresh = 0, ts_low = 0;
11221 
11222 	/* Return the next guy to be re-transmitted */
11223 	if (RB_EMPTY(&rack->r_ctl.rc_mtree)) {
11224 		return (NULL);
11225 	}
11226 	if (tp->t_flags & TF_SENTFIN) {
11227 		/* retran the end FIN? */
11228 		return (NULL);
11229 	}
11230 	/* ok lets look at this one */
11231 	rsm = TAILQ_FIRST(&rack->r_ctl.rc_tmap);
11232 	if (rsm && ((rsm->r_flags & RACK_ACKED) == 0)) {
11233 		goto check_it;
11234 	}
11235 	rsm = rack_find_lowest_rsm(rack);
11236 	if (rsm == NULL) {
11237 		return (NULL);
11238 	}
11239 check_it:
11240 	if (rsm->r_flags & RACK_ACKED) {
11241 		return (NULL);
11242 	}
11243 	if (((rsm->r_flags & RACK_SACK_PASSED) == 0) &&
11244 	    (rsm->r_dupack < DUP_ACK_THRESHOLD)) {
11245 		/* Its not yet ready */
11246 		return (NULL);
11247 	}
11248 	srtt = rack_grab_rtt(tp, rack);
11249 	idx = rsm->r_rtr_cnt - 1;
11250 	ts_low = rsm->r_tim_lastsent[idx];
11251 	thresh = rack_calc_thresh_rack(rack, srtt, tsused);
11252 	if ((tsused == ts_low) ||
11253 	    (TSTMP_LT(tsused, ts_low))) {
11254 		/* No time since sending */
11255 		return (NULL);
11256 	}
11257 	if ((tsused - ts_low) < thresh) {
11258 		/* It has not been long enough yet */
11259 		return (NULL);
11260 	}
11261 	if ((rsm->r_dupack >= DUP_ACK_THRESHOLD) ||
11262 	    ((rsm->r_flags & RACK_SACK_PASSED) &&
11263 	     (rack->sack_attack_disable == 0))) {
11264 		/*
11265 		 * We have passed the dup-ack threshold <or>
11266 		 * a SACK has indicated this is missing.
11267 		 * Note that if you are a declared attacker
11268 		 * it is only the dup-ack threshold that
11269 		 * will cause retransmits.
11270 		 */
11271 		/* log retransmit reason */
11272 		rack_log_retran_reason(rack, rsm, (tsused - ts_low), thresh, 1);
11273 		return (rsm);
11274 	}
11275 	return (NULL);
11276 }
11277 
11278 static void
11279 rack_log_pacing_delay_calc(struct tcp_rack *rack, uint32_t len, uint32_t slot,
11280 			   uint64_t bw_est, uint64_t bw, uint64_t len_time, int method,
11281 			   int line, struct rack_sendmap *rsm)
11282 {
11283 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
11284 		union tcp_log_stackspecific log;
11285 		struct timeval tv;
11286 
11287 		memset(&log, 0, sizeof(log));
11288 		log.u_bbr.flex1 = slot;
11289 		log.u_bbr.flex2 = len;
11290 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_min_segs;
11291 		log.u_bbr.flex4 = rack->r_ctl.rc_pace_max_segs;
11292 		log.u_bbr.flex5 = rack->r_ctl.rack_per_of_gp_ss;
11293 		log.u_bbr.flex6 = rack->r_ctl.rack_per_of_gp_ca;
11294 		log.u_bbr.use_lt_bw = rack->app_limited_needs_set;
11295 		log.u_bbr.use_lt_bw <<= 1;
11296 		log.u_bbr.use_lt_bw = rack->rc_gp_filled;
11297 		log.u_bbr.use_lt_bw <<= 1;
11298 		log.u_bbr.use_lt_bw |= rack->measure_saw_probe_rtt;
11299 		log.u_bbr.use_lt_bw <<= 1;
11300 		log.u_bbr.use_lt_bw |= rack->in_probe_rtt;
11301 		log.u_bbr.pkt_epoch = line;
11302 		log.u_bbr.applimited = rack->r_ctl.rack_per_of_gp_rec;
11303 		log.u_bbr.bw_inuse = bw_est;
11304 		log.u_bbr.delRate = bw;
11305 		if (rack->r_ctl.gp_bw == 0)
11306 			log.u_bbr.cur_del_rate = 0;
11307 		else
11308 			log.u_bbr.cur_del_rate = rack_get_bw(rack);
11309 		log.u_bbr.rttProp = len_time;
11310 		log.u_bbr.pkts_out = rack->r_ctl.rc_rack_min_rtt;
11311 		log.u_bbr.lost = rack->r_ctl.rc_probertt_sndmax_atexit;
11312 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, rsm);
11313 		if (rack->r_ctl.cwnd_to_use < rack->rc_tp->snd_ssthresh) {
11314 			/* We are in slow start */
11315 			log.u_bbr.flex7 = 1;
11316 		} else {
11317 			/* we are on congestion avoidance */
11318 			log.u_bbr.flex7 = 0;
11319 		}
11320 		log.u_bbr.flex8 = method;
11321 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
11322 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
11323 		log.u_bbr.cwnd_gain = rack->rc_gp_saw_rec;
11324 		log.u_bbr.cwnd_gain <<= 1;
11325 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ss;
11326 		log.u_bbr.cwnd_gain <<= 1;
11327 		log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ca;
11328 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
11329 		    &rack->rc_inp->inp_socket->so_rcv,
11330 		    &rack->rc_inp->inp_socket->so_snd,
11331 		    BBR_LOG_HPTSI_CALC, 0,
11332 		    0, &log, false, &tv);
11333 	}
11334 }
11335 
11336 static uint32_t
11337 rack_get_pacing_len(struct tcp_rack *rack, uint64_t bw, uint32_t mss)
11338 {
11339 	uint32_t new_tso, user_max;
11340 
11341 	user_max = rack->rc_user_set_max_segs * mss;
11342 	if (rack->rc_force_max_seg) {
11343 		return (user_max);
11344 	}
11345 	if (rack->use_fixed_rate &&
11346 	    ((rack->r_ctl.crte == NULL) ||
11347 	     (bw != rack->r_ctl.crte->rate))) {
11348 		/* Use the user mss since we are not exactly matched */
11349 		return (user_max);
11350 	}
11351 	new_tso = tcp_get_pacing_burst_size(rack->rc_tp, bw, mss, rack_pace_one_seg, rack->r_ctl.crte, NULL);
11352 	if (new_tso > user_max)
11353 		new_tso = user_max;
11354 	return(new_tso);
11355 }
11356 
11357 static void
11358 rack_log_hdwr_pacing(struct tcp_rack *rack, const struct ifnet *ifp,
11359 		     uint64_t rate, uint64_t hw_rate, int line,
11360 		     int error)
11361 {
11362 	if (rack->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
11363 		union tcp_log_stackspecific log;
11364 		struct timeval tv;
11365 
11366 		memset(&log, 0, sizeof(log));
11367 		log.u_bbr.flex1 = ((hw_rate >> 32) & 0x00000000ffffffff);
11368 		log.u_bbr.flex2 = (hw_rate & 0x00000000ffffffff);
11369 		log.u_bbr.flex3 = (((uint64_t)ifp  >> 32) & 0x00000000ffffffff);
11370 		log.u_bbr.flex4 = ((uint64_t)ifp & 0x00000000ffffffff);
11371 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
11372 		log.u_bbr.bw_inuse = rate;
11373 		log.u_bbr.flex5 = line;
11374 		log.u_bbr.flex6 = error;
11375 		log.u_bbr.applimited = rack->r_ctl.rc_pace_max_segs;
11376 		log.u_bbr.flex8 = rack->use_fixed_rate;
11377 		log.u_bbr.flex8 <<= 1;
11378 		log.u_bbr.flex8 |= rack->rack_hdrw_pacing;
11379 		log.u_bbr.pkts_out = rack->rc_tp->t_maxseg;
11380 		TCP_LOG_EVENTP(rack->rc_tp, NULL,
11381 		    &rack->rc_inp->inp_socket->so_rcv,
11382 		    &rack->rc_inp->inp_socket->so_snd,
11383 		    BBR_LOG_HDWR_PACE, 0,
11384 		    0, &log, false, &tv);
11385 	}
11386 }
11387 
11388 static int32_t
11389 pace_to_fill_cwnd(struct tcp_rack *rack, int32_t slot, uint32_t len, uint32_t segsiz)
11390 {
11391 	uint64_t lentim, fill_bw;
11392 
11393 	/* Lets first see if we are full, if so continue with normal rate */
11394 	if (ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked) > rack->r_ctl.cwnd_to_use)
11395 		return (slot);
11396 	if ((ctf_outstanding(rack->rc_tp) + (segsiz-1)) > rack->rc_tp->snd_wnd)
11397 		return (slot);
11398 	if (rack->r_ctl.rc_last_us_rtt == 0)
11399 		return (slot);
11400 	if (rack->rc_pace_fill_if_rttin_range &&
11401 	    (rack->r_ctl.rc_last_us_rtt >=
11402 	     (get_filter_value_small(&rack->r_ctl.rc_gp_min_rtt) * rack->rtt_limit_mul))) {
11403 		/* The rtt is huge, N * smallest, lets not fill */
11404 		return (slot);
11405 	}
11406 	/*
11407 	 * first lets calculate the b/w based on the last us-rtt
11408 	 * and the sndwnd.
11409 	 */
11410 	fill_bw = rack->r_ctl.cwnd_to_use;
11411 	/* Take the rwnd if its smaller */
11412 	if (fill_bw > rack->rc_tp->snd_wnd)
11413 		fill_bw = rack->rc_tp->snd_wnd;
11414 	fill_bw *= (uint64_t)HPTS_USEC_IN_SEC;
11415 	fill_bw /= (uint64_t)rack->r_ctl.rc_last_us_rtt;
11416 	/* We are below the min b/w */
11417 	if (fill_bw < RACK_MIN_BW)
11418 		return (slot);
11419 	/*
11420 	 * Ok fill_bw holds our mythical b/w to fill the cwnd
11421 	 * in a rtt, what does that time wise equate too?
11422 	 */
11423 	lentim = (uint64_t)(len) * (uint64_t)HPTS_USEC_IN_SEC;
11424 	lentim /= fill_bw;
11425 	if (lentim < slot) {
11426 		rack_log_pacing_delay_calc(rack, len, slot, fill_bw,
11427 					   0, lentim, 12, __LINE__, NULL);
11428 		return ((int32_t)lentim);
11429 	} else
11430 		return (slot);
11431 }
11432 
11433 static int32_t
11434 rack_get_pacing_delay(struct tcp_rack *rack, struct tcpcb *tp, uint32_t len, struct rack_sendmap *rsm, uint32_t segsiz)
11435 {
11436 	struct rack_sendmap *lrsm;
11437 	int32_t slot = 0;
11438 	int err;
11439 
11440 	if (rack->rc_always_pace == 0) {
11441 		/*
11442 		 * We use the most optimistic possible cwnd/srtt for
11443 		 * sending calculations. This will make our
11444 		 * calculation anticipate getting more through
11445 		 * quicker then possible. But thats ok we don't want
11446 		 * the peer to have a gap in data sending.
11447 		 */
11448 		uint32_t srtt, cwnd, tr_perms = 0;
11449 		int32_t reduce = 0;
11450 
11451 	old_method:
11452 		/*
11453 		 * We keep no precise pacing with the old method
11454 		 * instead we use the pacer to mitigate bursts.
11455 		 */
11456 		rack->r_ctl.rc_agg_delayed = 0;
11457 		rack->r_early = 0;
11458 		rack->r_late = 0;
11459 		rack->r_ctl.rc_agg_early = 0;
11460 		if (rack->r_ctl.rc_rack_min_rtt)
11461 			srtt = rack->r_ctl.rc_rack_min_rtt;
11462 		else
11463 			srtt = TICKS_2_MSEC((tp->t_srtt >> TCP_RTT_SHIFT));
11464 		if (rack->r_ctl.rc_rack_largest_cwnd)
11465 			cwnd = rack->r_ctl.rc_rack_largest_cwnd;
11466 		else
11467 			cwnd = rack->r_ctl.cwnd_to_use;
11468 		tr_perms = cwnd / srtt;
11469 		if (tr_perms == 0) {
11470 			tr_perms = ctf_fixed_maxseg(tp);
11471 		}
11472 		/*
11473 		 * Calculate how long this will take to drain, if
11474 		 * the calculation comes out to zero, thats ok we
11475 		 * will use send_a_lot to possibly spin around for
11476 		 * more increasing tot_len_this_send to the point
11477 		 * that its going to require a pace, or we hit the
11478 		 * cwnd. Which in that case we are just waiting for
11479 		 * a ACK.
11480 		 */
11481 		slot = len / tr_perms;
11482 		/* Now do we reduce the time so we don't run dry? */
11483 		if (slot && rack_slot_reduction) {
11484 			reduce = (slot / rack_slot_reduction);
11485 			if (reduce < slot) {
11486 				slot -= reduce;
11487 			} else
11488 				slot = 0;
11489 		}
11490 		slot *=  HPTS_USEC_IN_MSEC;
11491 		if (rsm == NULL) {
11492 			/*
11493 			 * We always consider ourselves app limited with old style
11494 			 * that are not retransmits. This could be the initial
11495 			 * measurement, but thats ok its all setup and specially
11496 			 * handled. If another send leaks out, then that too will
11497 			 * be mark app-limited.
11498 			 */
11499 			lrsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
11500 			if (lrsm && ((lrsm->r_flags & RACK_APP_LIMITED) == 0)) {
11501 				rack->r_ctl.rc_first_appl = lrsm;
11502 				lrsm->r_flags |= RACK_APP_LIMITED;
11503 				rack->r_ctl.rc_app_limited_cnt++;
11504 			}
11505 		}
11506 		rack_log_pacing_delay_calc(rack, len, slot, tr_perms, reduce, 0, 7, __LINE__, NULL);
11507 	} else {
11508 		uint64_t bw_est, res, lentim, rate_wanted;
11509 		uint32_t orig_val, srtt, segs, oh;
11510 
11511 		if ((rack->r_rr_config == 1) && rsm) {
11512 			return (rack->r_ctl.rc_min_to * HPTS_USEC_IN_MSEC);
11513 		}
11514 		if (rack->use_fixed_rate) {
11515 			rate_wanted = bw_est = rack_get_fixed_pacing_bw(rack);
11516 		} else if ((rack->r_ctl.init_rate == 0) &&
11517 #ifdef NETFLIX_PEAKRATE
11518 			   (rack->rc_tp->t_maxpeakrate == 0) &&
11519 #endif
11520 			   (rack->r_ctl.gp_bw == 0)) {
11521 			/* no way to yet do an estimate */
11522 			bw_est = rate_wanted = 0;
11523 		} else {
11524 			bw_est = rack_get_bw(rack);
11525 			rate_wanted = rack_get_output_bw(rack, bw_est, rsm);
11526 		}
11527 		if ((bw_est == 0) || (rate_wanted == 0)) {
11528 			/*
11529 			 * No way yet to make a b/w estimate or
11530 			 * our raise is set incorrectly.
11531 			 */
11532 			goto old_method;
11533 		}
11534 		/* We need to account for all the overheads */
11535 		segs = (len + segsiz - 1) / segsiz;
11536 		/*
11537 		 * We need the diff between 1514 bytes (e-mtu with e-hdr)
11538 		 * and how much data we put in each packet. Yes this
11539 		 * means we may be off if we are larger than 1500 bytes
11540 		 * or smaller. But this just makes us more conservative.
11541 		 */
11542 		if (ETHERNET_SEGMENT_SIZE > segsiz)
11543 			oh = ETHERNET_SEGMENT_SIZE - segsiz;
11544 		else
11545 			oh = 0;
11546 		segs *= oh;
11547 		lentim = (uint64_t)(len + segs)  * (uint64_t)HPTS_USEC_IN_SEC;
11548 		res = lentim / rate_wanted;
11549 		slot = (uint32_t)res;
11550 		orig_val = rack->r_ctl.rc_pace_max_segs;
11551 		rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
11552 		/* Did we change the TSO size, if so log it */
11553 		if (rack->r_ctl.rc_pace_max_segs != orig_val)
11554 			rack_log_pacing_delay_calc(rack, len, slot, orig_val, 0, 0, 15, __LINE__, NULL);
11555 		if ((rack->rc_pace_to_cwnd) &&
11556 		    (rack->in_probe_rtt == 0) &&
11557 		    (IN_RECOVERY(rack->rc_tp->t_flags) == 0)) {
11558 			/*
11559 			 * We want to pace at our rate *or* faster to
11560 			 * fill the cwnd to the max if its not full.
11561 			 */
11562 			slot = pace_to_fill_cwnd(rack, slot, (len+segs), segsiz);
11563 		}
11564 		if ((rack->rc_inp->inp_route.ro_nh != NULL) &&
11565 		    (rack->rc_inp->inp_route.ro_nh->nh_ifp != NULL)) {
11566 			if ((rack->rack_hdw_pace_ena) &&
11567 			    (rack->rack_hdrw_pacing == 0) &&
11568 			    (rack->rack_attempt_hdwr_pace == 0)) {
11569 				/*
11570 				 * Lets attempt to turn on hardware pacing
11571 				 * if we can.
11572 				 */
11573 				rack->rack_attempt_hdwr_pace = 1;
11574 				rack->r_ctl.crte = tcp_set_pacing_rate(rack->rc_tp,
11575 								       rack->rc_inp->inp_route.ro_nh->nh_ifp,
11576 								       rate_wanted,
11577 								       RS_PACING_GEQ,
11578 								       &err, NULL);
11579 				if (rack->r_ctl.crte) {
11580 					rack->rack_hdrw_pacing = 1;
11581 					rack->r_ctl.rc_pace_max_segs = tcp_get_pacing_burst_size(rack->rc_tp, rate_wanted, segsiz,
11582 												 0, rack->r_ctl.crte,
11583 												 NULL);
11584 					rack_log_hdwr_pacing(rack, rack->rc_inp->inp_route.ro_nh->nh_ifp,
11585 							     rate_wanted, rack->r_ctl.crte->rate, __LINE__,
11586 							     err);
11587 				}
11588 			} else if (rack->rack_hdrw_pacing &&
11589 				   (rack->r_ctl.crte->rate != rate_wanted)) {
11590 				/* Do we need to adjust our rate? */
11591 				const struct tcp_hwrate_limit_table *nrte;
11592 
11593 				nrte = tcp_chg_pacing_rate(rack->r_ctl.crte,
11594 							   rack->rc_tp,
11595 							   rack->rc_inp->inp_route.ro_nh->nh_ifp,
11596 							   rate_wanted,
11597 							   RS_PACING_GEQ,
11598 							   &err, NULL);
11599 				if (nrte == NULL) {
11600 					/* Lost the rate */
11601 					rack->rack_hdrw_pacing = 0;
11602 					rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
11603 				} else if (nrte != rack->r_ctl.crte) {
11604 					rack->r_ctl.crte = nrte;
11605 					rack->r_ctl.rc_pace_max_segs = tcp_get_pacing_burst_size(rack->rc_tp, rate_wanted,
11606 												 segsiz, 0,
11607 												 rack->r_ctl.crte,
11608 												 NULL);
11609 					rack_log_hdwr_pacing(rack, rack->rc_inp->inp_route.ro_nh->nh_ifp,
11610 							     rate_wanted, rack->r_ctl.crte->rate, __LINE__,
11611 							     err);
11612 				}
11613 			}
11614 		}
11615 		if (rack_limit_time_with_srtt &&
11616 		    (rack->use_fixed_rate == 0) &&
11617 #ifdef NETFLIX_PEAKRATE
11618 		    (rack->rc_tp->t_maxpeakrate == 0) &&
11619 #endif
11620 		    (rack->rack_hdrw_pacing == 0)) {
11621 			/*
11622 			 * Sanity check, we do not allow the pacing delay
11623 			 * to be longer than the SRTT of the path. If it is
11624 			 * a slow path, then adding a packet should increase
11625 			 * the RTT and compensate for this i.e. the srtt will
11626 			 * be greater so the allowed pacing time will be greater.
11627 			 *
11628 			 * Note this restriction is not for where a peak rate
11629 			 * is set, we are doing fixed pacing or hardware pacing.
11630 			 */
11631 			if (rack->rc_tp->t_srtt)
11632 				srtt = (TICKS_2_USEC(rack->rc_tp->t_srtt) >> TCP_RTT_SHIFT);
11633 			else
11634 				srtt = RACK_INITIAL_RTO * HPTS_USEC_IN_MSEC;	/* its in ms convert */
11635 			if (srtt < slot) {
11636 				rack_log_pacing_delay_calc(rack, srtt, slot, rate_wanted, bw_est, lentim, 99, __LINE__, NULL);
11637 				slot = srtt;
11638 			}
11639 		}
11640 		rack_log_pacing_delay_calc(rack, len, slot, rate_wanted, bw_est, lentim, 2, __LINE__, rsm);
11641 	}
11642 	if (slot)
11643 		counter_u64_add(rack_calc_nonzero, 1);
11644 	else
11645 		counter_u64_add(rack_calc_zero, 1);
11646 	return (slot);
11647 }
11648 
11649 static void
11650 rack_start_gp_measurement(struct tcpcb *tp, struct tcp_rack *rack,
11651     tcp_seq startseq, uint32_t sb_offset)
11652 {
11653 	struct rack_sendmap *my_rsm = NULL;
11654 	struct rack_sendmap fe;
11655 
11656 	if (tp->t_state < TCPS_ESTABLISHED) {
11657 		/*
11658 		 * We don't start any measurements if we are
11659 		 * not at least established.
11660 		 */
11661 		return;
11662 	}
11663 	tp->t_flags |= TF_GPUTINPROG;
11664 	rack->r_ctl.rc_gp_lowrtt = 0xffffffff;
11665 	rack->r_ctl.rc_gp_high_rwnd = rack->rc_tp->snd_wnd;
11666 	tp->gput_seq = startseq;
11667 	rack->app_limited_needs_set = 0;
11668 	if (rack->in_probe_rtt)
11669 		rack->measure_saw_probe_rtt = 1;
11670 	else if ((rack->measure_saw_probe_rtt) &&
11671 		 (SEQ_GEQ(tp->gput_seq, rack->r_ctl.rc_probertt_sndmax_atexit)))
11672 		rack->measure_saw_probe_rtt = 0;
11673 	if (rack->rc_gp_filled)
11674 		tp->gput_ts = tcp_tv_to_usectick(&rack->r_ctl.act_rcv_time);
11675 	else {
11676 		/* Special case initial measurement */
11677 		rack->r_ctl.rc_gp_output_ts = tp->gput_ts = tcp_get_usecs(NULL);
11678 	}
11679 	/*
11680 	 * We take a guess out into the future,
11681 	 * if we have no measurement and no
11682 	 * initial rate, we measure the first
11683 	 * initial-windows worth of data to
11684 	 * speed up getting some GP measurement and
11685 	 * thus start pacing.
11686 	 */
11687 	if ((rack->rc_gp_filled == 0) && (rack->r_ctl.init_rate == 0)) {
11688 		rack->app_limited_needs_set = 1;
11689 		tp->gput_ack = startseq + max(rc_init_window(rack),
11690 					      (MIN_GP_WIN * ctf_fixed_maxseg(tp)));
11691 		rack_log_pacing_delay_calc(rack,
11692 					   tp->gput_seq,
11693 					   tp->gput_ack,
11694 					   0,
11695 					   tp->gput_ts,
11696 					   rack->r_ctl.rc_app_limited_cnt,
11697 					   9,
11698 					   __LINE__, NULL);
11699 		return;
11700 	}
11701 	if (sb_offset) {
11702 		/*
11703 		 * We are out somewhere in the sb
11704 		 * can we use the already outstanding data?
11705 		 */
11706 
11707 		if (rack->r_ctl.rc_app_limited_cnt == 0) {
11708 			/*
11709 			 * Yes first one is good and in this case
11710 			 * the tp->gput_ts is correctly set based on
11711 			 * the last ack that arrived (no need to
11712 			 * set things up when an ack comes in).
11713 			 */
11714 			my_rsm = RB_MIN(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
11715 			if ((my_rsm == NULL) ||
11716 			    (my_rsm->r_rtr_cnt != 1)) {
11717 				/* retransmission? */
11718 				goto use_latest;
11719 			}
11720 		} else {
11721 			if (rack->r_ctl.rc_first_appl == NULL) {
11722 				/*
11723 				 * If rc_first_appl is NULL
11724 				 * then the cnt should be 0.
11725 				 * This is probably an error, maybe
11726 				 * a KASSERT would be approprate.
11727 				 */
11728 				goto use_latest;
11729 			}
11730 			/*
11731 			 * If we have a marker pointer to the last one that is
11732 			 * app limited we can use that, but we need to set
11733 			 * things up so that when it gets ack'ed we record
11734 			 * the ack time (if its not already acked).
11735 			 */
11736 			rack->app_limited_needs_set = 1;
11737 			/*
11738 			 * We want to get to the rsm that is either
11739 			 * next with space i.e. over 1 MSS or the one
11740 			 * after that (after the app-limited).
11741 			 */
11742 			my_rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree,
11743 					 rack->r_ctl.rc_first_appl);
11744 			if (my_rsm) {
11745 				if ((my_rsm->r_end - my_rsm->r_start) <= ctf_fixed_maxseg(tp))
11746 					/* Have to use the next one */
11747 					my_rsm = RB_NEXT(rack_rb_tree_head, &rack->r_ctl.rc_mtree,
11748 							 my_rsm);
11749 				else {
11750 					/* Use after the first MSS of it is acked */
11751 					tp->gput_seq = my_rsm->r_start + ctf_fixed_maxseg(tp);
11752 					goto start_set;
11753 				}
11754 			}
11755 			if ((my_rsm == NULL) ||
11756 			    (my_rsm->r_rtr_cnt != 1)) {
11757 				/*
11758 				 * Either its a retransmit or
11759 				 * the last is the app-limited one.
11760 				 */
11761 				goto use_latest;
11762 			}
11763 		}
11764 		tp->gput_seq = my_rsm->r_start;
11765 start_set:
11766 		if (my_rsm->r_flags & RACK_ACKED) {
11767 			/*
11768 			 * This one has been acked use the arrival ack time
11769 			 */
11770 			tp->gput_ts = my_rsm->r_ack_arrival;
11771 			rack->app_limited_needs_set = 0;
11772 		}
11773 		rack->r_ctl.rc_gp_output_ts = my_rsm->usec_orig_send;
11774 		tp->gput_ack = tp->gput_seq + rack_get_measure_window(tp, rack);
11775 		rack_log_pacing_delay_calc(rack,
11776 					   tp->gput_seq,
11777 					   tp->gput_ack,
11778 					   (uint64_t)my_rsm,
11779 					   tp->gput_ts,
11780 					   rack->r_ctl.rc_app_limited_cnt,
11781 					   9,
11782 					   __LINE__, NULL);
11783 		return;
11784 	}
11785 
11786 use_latest:
11787 	/*
11788 	 * We don't know how long we may have been
11789 	 * idle or if this is the first-send. Lets
11790 	 * setup the flag so we will trim off
11791 	 * the first ack'd data so we get a true
11792 	 * measurement.
11793 	 */
11794 	rack->app_limited_needs_set = 1;
11795 	tp->gput_ack = startseq + rack_get_measure_window(tp, rack);
11796 	/* Find this guy so we can pull the send time */
11797 	fe.r_start = startseq;
11798 	my_rsm = RB_FIND(rack_rb_tree_head, &rack->r_ctl.rc_mtree, &fe);
11799 	if (my_rsm) {
11800 		rack->r_ctl.rc_gp_output_ts = my_rsm->usec_orig_send;
11801 		if (my_rsm->r_flags & RACK_ACKED) {
11802 			/*
11803 			 * Unlikely since its probably what was
11804 			 * just transmitted (but I am paranoid).
11805 			 */
11806 			tp->gput_ts = my_rsm->r_ack_arrival;
11807 			rack->app_limited_needs_set = 0;
11808 		}
11809 		if (SEQ_LT(my_rsm->r_start, tp->gput_seq)) {
11810 			/* This also is unlikely */
11811 			tp->gput_seq = my_rsm->r_start;
11812 		}
11813 	} else {
11814 		/*
11815 		 * TSNH unless we have some send-map limit,
11816 		 * and even at that it should not be hitting
11817 		 * that limit (we should have stopped sending).
11818 		 */
11819 		rack->r_ctl.rc_gp_output_ts = tcp_get_usecs(NULL);
11820 	}
11821 	rack_log_pacing_delay_calc(rack,
11822 				   tp->gput_seq,
11823 				   tp->gput_ack,
11824 				   (uint64_t)my_rsm,
11825 				   tp->gput_ts,
11826 				   rack->r_ctl.rc_app_limited_cnt,
11827 				   9, __LINE__, NULL);
11828 }
11829 
11830 static inline uint32_t
11831 rack_what_can_we_send(struct tcpcb *tp, struct tcp_rack *rack,  uint32_t cwnd_to_use,
11832     uint32_t avail, int32_t sb_offset)
11833 {
11834 	uint32_t len;
11835 	uint32_t sendwin;
11836 
11837 	if (tp->snd_wnd > cwnd_to_use)
11838 		sendwin = cwnd_to_use;
11839 	else
11840 		sendwin = tp->snd_wnd;
11841 	if (ctf_outstanding(tp) >= tp->snd_wnd) {
11842 		/* We never want to go over our peers rcv-window */
11843 		len = 0;
11844 	} else {
11845 		uint32_t flight;
11846 
11847 		flight = ctf_flight_size(tp, rack->r_ctl.rc_sacked);
11848 		if (flight >= sendwin) {
11849 			/*
11850 			 * We have in flight what we are allowed by cwnd (if
11851 			 * it was rwnd blocking it would have hit above out
11852 			 * >= tp->snd_wnd).
11853 			 */
11854 			return (0);
11855 		}
11856 		len = sendwin - flight;
11857 		if ((len + ctf_outstanding(tp)) > tp->snd_wnd) {
11858 			/* We would send too much (beyond the rwnd) */
11859 			len = tp->snd_wnd - ctf_outstanding(tp);
11860 		}
11861 		if ((len + sb_offset) > avail) {
11862 			/*
11863 			 * We don't have that much in the SB, how much is
11864 			 * there?
11865 			 */
11866 			len = avail - sb_offset;
11867 		}
11868 	}
11869 	return (len);
11870 }
11871 
11872 static int
11873 rack_output(struct tcpcb *tp)
11874 {
11875 	struct socket *so;
11876 	uint32_t recwin;
11877 	uint32_t sb_offset;
11878 	int32_t len, flags, error = 0;
11879 	struct mbuf *m;
11880 	struct mbuf *mb;
11881 	uint32_t if_hw_tsomaxsegcount = 0;
11882 	uint32_t if_hw_tsomaxsegsize;
11883 	int32_t segsiz, minseg;
11884 	long tot_len_this_send = 0;
11885 	struct ip *ip = NULL;
11886 #ifdef TCPDEBUG
11887 	struct ipovly *ipov = NULL;
11888 #endif
11889 	struct udphdr *udp = NULL;
11890 	struct tcp_rack *rack;
11891 	struct tcphdr *th;
11892 	uint8_t pass = 0;
11893 	uint8_t mark = 0;
11894 	uint8_t wanted_cookie = 0;
11895 	u_char opt[TCP_MAXOLEN];
11896 	unsigned ipoptlen, optlen, hdrlen, ulen=0;
11897 	uint32_t rack_seq;
11898 
11899 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
11900 	unsigned ipsec_optlen = 0;
11901 
11902 #endif
11903 	int32_t idle, sendalot;
11904 	int32_t sub_from_prr = 0;
11905 	volatile int32_t sack_rxmit;
11906 	struct rack_sendmap *rsm = NULL;
11907 	int32_t tso, mtu;
11908 	struct tcpopt to;
11909 	int32_t slot = 0;
11910 	int32_t sup_rack = 0;
11911 	uint32_t cts, us_cts, delayed, early;
11912 	uint8_t hpts_calling, new_data_tlp = 0, doing_tlp = 0;
11913 	uint32_t cwnd_to_use;
11914 	int32_t do_a_prefetch;
11915 	int32_t prefetch_rsm = 0;
11916 	int32_t orig_len;
11917 	struct timeval tv;
11918 	int32_t prefetch_so_done = 0;
11919 	struct tcp_log_buffer *lgb = NULL;
11920 	struct inpcb *inp;
11921 	struct sockbuf *sb;
11922 #ifdef INET6
11923 	struct ip6_hdr *ip6 = NULL;
11924 	int32_t isipv6;
11925 #endif
11926 	uint8_t filled_all = 0;
11927 	bool hw_tls = false;
11928 
11929 	/* setup and take the cache hits here */
11930 	rack = (struct tcp_rack *)tp->t_fb_ptr;
11931 	inp = rack->rc_inp;
11932 	so = inp->inp_socket;
11933 	sb = &so->so_snd;
11934 	kern_prefetch(sb, &do_a_prefetch);
11935 	do_a_prefetch = 1;
11936 	hpts_calling = inp->inp_hpts_calls;
11937 	hw_tls = (so->so_snd.sb_flags & SB_TLS_IFNET) != 0;
11938 
11939 	NET_EPOCH_ASSERT();
11940 	INP_WLOCK_ASSERT(inp);
11941 #ifdef TCP_OFFLOAD
11942 	if (tp->t_flags & TF_TOE)
11943 		return (tcp_offload_output(tp));
11944 #endif
11945 	/*
11946 	 * For TFO connections in SYN_RECEIVED, only allow the initial
11947 	 * SYN|ACK and those sent by the retransmit timer.
11948 	 */
11949 	if (IS_FASTOPEN(tp->t_flags) &&
11950 	    (tp->t_state == TCPS_SYN_RECEIVED) &&
11951 	    SEQ_GT(tp->snd_max, tp->snd_una) &&    /* initial SYN|ACK sent */
11952 	    (rack->r_ctl.rc_resend == NULL))         /* not a retransmit */
11953 		return (0);
11954 #ifdef INET6
11955 	if (rack->r_state) {
11956 		/* Use the cache line loaded if possible */
11957 		isipv6 = rack->r_is_v6;
11958 	} else {
11959 		isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
11960 	}
11961 #endif
11962 	early = 0;
11963 	us_cts = tcp_get_usecs(&tv);
11964 	cts = tcp_tv_to_mssectick(&tv);
11965 	if (((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0) &&
11966 	    inp->inp_in_hpts) {
11967 		/*
11968 		 * We are on the hpts for some timer but not hptsi output.
11969 		 * Remove from the hpts unconditionally.
11970 		 */
11971 		rack_timer_cancel(tp, rack, cts, __LINE__);
11972 	}
11973 	/* Are we pacing and late? */
11974 	if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
11975 	    TSTMP_GEQ(us_cts, rack->r_ctl.rc_last_output_to)) {
11976 		/* We are delayed */
11977 		delayed = us_cts - rack->r_ctl.rc_last_output_to;
11978 	} else {
11979 		delayed = 0;
11980 	}
11981 	/* Do the timers, which may override the pacer  */
11982 	if (rack->r_ctl.rc_hpts_flags & PACE_TMR_MASK) {
11983 		if (rack_process_timers(tp, rack, cts, hpts_calling)) {
11984 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_ATIMER], 1);
11985 			return (0);
11986 		}
11987 	}
11988 	if ((rack->r_timer_override) ||
11989 	    (delayed) ||
11990 	    (tp->t_state < TCPS_ESTABLISHED)) {
11991 		if (tp->t_inpcb->inp_in_hpts)
11992 			tcp_hpts_remove(tp->t_inpcb, HPTS_REMOVE_OUTPUT);
11993 	} else if (tp->t_inpcb->inp_in_hpts) {
11994 		/*
11995 		 * On the hpts you can't pass even if ACKNOW is on, we will
11996 		 * when the hpts fires.
11997 		 */
11998 		counter_u64_add(rack_out_size[TCP_MSS_ACCT_INPACE], 1);
11999 		return (0);
12000 	}
12001 	inp->inp_hpts_calls = 0;
12002 	/* Finish out both pacing early and late accounting */
12003 	if ((rack->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
12004 	    TSTMP_GT(rack->r_ctl.rc_last_output_to, us_cts)) {
12005 		early = rack->r_ctl.rc_last_output_to - us_cts;
12006 	} else
12007 		early = 0;
12008 	if (delayed) {
12009 		rack->r_ctl.rc_agg_delayed += delayed;
12010 		rack->r_late = 1;
12011 	} else if (early) {
12012 		rack->r_ctl.rc_agg_early += early;
12013 		rack->r_early = 1;
12014 	}
12015 	/* Now that early/late accounting is done turn off the flag */
12016 	rack->r_ctl.rc_hpts_flags &= ~PACE_PKT_OUTPUT;
12017 	rack->r_wanted_output = 0;
12018 	rack->r_timer_override = 0;
12019 	/*
12020 	 * For TFO connections in SYN_SENT or SYN_RECEIVED,
12021 	 * only allow the initial SYN or SYN|ACK and those sent
12022 	 * by the retransmit timer.
12023 	 */
12024 	if (IS_FASTOPEN(tp->t_flags) &&
12025 	    ((tp->t_state == TCPS_SYN_RECEIVED) ||
12026 	     (tp->t_state == TCPS_SYN_SENT)) &&
12027 	    SEQ_GT(tp->snd_max, tp->snd_una) && /* initial SYN or SYN|ACK sent */
12028 	    (tp->t_rxtshift == 0)) {              /* not a retransmit */
12029 		cwnd_to_use = rack->r_ctl.cwnd_to_use = tp->snd_cwnd;
12030 		goto just_return_nolock;
12031 	}
12032 	/*
12033 	 * Determine length of data that should be transmitted, and flags
12034 	 * that will be used. If there is some data or critical controls
12035 	 * (SYN, RST) to send, then transmit; otherwise, investigate
12036 	 * further.
12037 	 */
12038 	idle = (tp->t_flags & TF_LASTIDLE) || (tp->snd_max == tp->snd_una);
12039 	if (tp->t_idle_reduce) {
12040 		if (idle && ((ticks - tp->t_rcvtime) >= tp->t_rxtcur))
12041 			rack_cc_after_idle(rack, tp);
12042 	}
12043 	tp->t_flags &= ~TF_LASTIDLE;
12044 	if (idle) {
12045 		if (tp->t_flags & TF_MORETOCOME) {
12046 			tp->t_flags |= TF_LASTIDLE;
12047 			idle = 0;
12048 		}
12049 	}
12050 	if ((tp->snd_una == tp->snd_max) &&
12051 	    rack->r_ctl.rc_went_idle_time &&
12052 	    TSTMP_GT(us_cts, rack->r_ctl.rc_went_idle_time)) {
12053 		idle = us_cts - rack->r_ctl.rc_went_idle_time;
12054 		if (idle > rack_min_probertt_hold) {
12055 			/* Count as a probe rtt */
12056 			if (rack->in_probe_rtt == 0) {
12057 				rack->r_ctl.rc_lower_rtt_us_cts = us_cts;
12058 				rack->r_ctl.rc_time_probertt_entered = rack->r_ctl.rc_lower_rtt_us_cts;
12059 				rack->r_ctl.rc_time_probertt_starts = rack->r_ctl.rc_lower_rtt_us_cts;
12060 				rack->r_ctl.rc_time_of_last_probertt = rack->r_ctl.rc_lower_rtt_us_cts;
12061 			} else {
12062 				rack_exit_probertt(rack, us_cts);
12063 			}
12064 		}
12065 		idle = 0;
12066 	}
12067 again:
12068 	/*
12069 	 * If we've recently taken a timeout, snd_max will be greater than
12070 	 * snd_nxt.  There may be SACK information that allows us to avoid
12071 	 * resending already delivered data.  Adjust snd_nxt accordingly.
12072 	 */
12073 	sendalot = 0;
12074 	us_cts = tcp_get_usecs(&tv);
12075 	cts = tcp_tv_to_mssectick(&tv);
12076 	tso = 0;
12077 	mtu = 0;
12078 	segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
12079 	minseg = segsiz;
12080 	sb_offset = tp->snd_max - tp->snd_una;
12081 	cwnd_to_use = rack->r_ctl.cwnd_to_use = tp->snd_cwnd;
12082 #ifdef NETFLIX_SHARED_CWND
12083 	if ((tp->t_flags2 & TF2_TCP_SCWND_ALLOWED) &&
12084 	    rack->rack_enable_scwnd) {
12085 		/* We are doing cwnd sharing */
12086 		if (rack->rc_gp_filled &&
12087 		    (rack->rack_attempted_scwnd == 0) &&
12088 		    (rack->r_ctl.rc_scw == NULL) &&
12089 		    tp->t_lib) {
12090 			/* The pcbid is in, lets make an attempt */
12091 			counter_u64_add(rack_try_scwnd, 1);
12092 			rack->rack_attempted_scwnd = 1;
12093 			rack->r_ctl.rc_scw = tcp_shared_cwnd_alloc(tp,
12094 								   &rack->r_ctl.rc_scw_index,
12095 								   segsiz);
12096 		}
12097 		if (rack->r_ctl.rc_scw &&
12098 		    (rack->rack_scwnd_is_idle == 1) &&
12099 		    (rack->rc_in_persist == 0) &&
12100 		    sbavail(sb)) {
12101 			/* we are no longer out of data */
12102 			tcp_shared_cwnd_active(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
12103 			rack->rack_scwnd_is_idle = 0;
12104 		}
12105 		if (rack->r_ctl.rc_scw) {
12106 			/* First lets update and get the cwnd */
12107 			rack->r_ctl.cwnd_to_use = cwnd_to_use = tcp_shared_cwnd_update(rack->r_ctl.rc_scw,
12108 								    rack->r_ctl.rc_scw_index,
12109 								    tp->snd_cwnd, tp->snd_wnd, segsiz);
12110 		}
12111 	}
12112 #endif
12113 	flags = tcp_outflags[tp->t_state];
12114 	while (rack->rc_free_cnt < rack_free_cache) {
12115 		rsm = rack_alloc(rack);
12116 		if (rsm == NULL) {
12117 			if (inp->inp_hpts_calls)
12118 				/* Retry in a ms */
12119 				slot = (1 * HPTS_USEC_IN_MSEC);
12120 			goto just_return_nolock;
12121 		}
12122 		TAILQ_INSERT_TAIL(&rack->r_ctl.rc_free, rsm, r_tnext);
12123 		rack->rc_free_cnt++;
12124 		rsm = NULL;
12125 	}
12126 	if (inp->inp_hpts_calls)
12127 		inp->inp_hpts_calls = 0;
12128 	sack_rxmit = 0;
12129 	len = 0;
12130 	rsm = NULL;
12131 	if (flags & TH_RST) {
12132 		SOCKBUF_LOCK(sb);
12133 		goto send;
12134 	}
12135 	if (rack->r_ctl.rc_resend) {
12136 		/* Retransmit timer */
12137 		rsm = rack->r_ctl.rc_resend;
12138 		rack->r_ctl.rc_resend = NULL;
12139 		rsm->r_flags &= ~RACK_TLP;
12140 		len = rsm->r_end - rsm->r_start;
12141 		sack_rxmit = 1;
12142 		sendalot = 0;
12143 		KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start),
12144 			("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p",
12145 			 __func__, __LINE__,
12146 			 rsm->r_start, tp->snd_una, tp, rack, rsm));
12147 		sb_offset = rsm->r_start - tp->snd_una;
12148 		if (len >= segsiz)
12149 			len = segsiz;
12150 	} else if ((rack->rc_in_persist == 0) &&
12151 		   ((rsm = tcp_rack_output(tp, rack, cts)) != NULL)) {
12152 		/* We have a retransmit that takes precedence */
12153 		rsm->r_flags &= ~RACK_TLP;
12154 		if ((!IN_RECOVERY(tp->t_flags)) &&
12155 		    ((tp->t_flags & (TF_WASFRECOVERY | TF_WASCRECOVERY)) == 0)) {
12156 			/* Enter recovery if not induced by a time-out */
12157 			rack->r_ctl.rc_rsm_start = rsm->r_start;
12158 			rack->r_ctl.rc_cwnd_at = tp->snd_cwnd;
12159 			rack->r_ctl.rc_ssthresh_at = tp->snd_ssthresh;
12160 			rack_cong_signal(tp, NULL, CC_NDUPACK);
12161 			/*
12162 			 * When we enter recovery we need to assure we send
12163 			 * one packet.
12164 			 */
12165 			if (rack->rack_no_prr == 0) {
12166 				rack->r_ctl.rc_prr_sndcnt = segsiz;
12167 				rack_log_to_prr(rack, 13, 0);
12168 			}
12169 		}
12170 #ifdef INVARIANTS
12171 		if (SEQ_LT(rsm->r_start, tp->snd_una)) {
12172 			panic("Huh, tp:%p rack:%p rsm:%p start:%u < snd_una:%u\n",
12173 			      tp, rack, rsm, rsm->r_start, tp->snd_una);
12174 		}
12175 #endif
12176 		len = rsm->r_end - rsm->r_start;
12177 		KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start),
12178 			("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p",
12179 			 __func__, __LINE__,
12180 			 rsm->r_start, tp->snd_una, tp, rack, rsm));
12181 		sb_offset = rsm->r_start - tp->snd_una;
12182 		/* Can we send it within the PRR boundary? */
12183 		if (rack->rack_no_prr == 0) {
12184 			if ((rack->use_rack_rr == 0) && (len > rack->r_ctl.rc_prr_sndcnt)) {
12185 				/* It does not fit */
12186 				if ((ctf_flight_size(tp, rack->r_ctl.rc_sacked) > len) &&
12187 				    (rack->r_ctl.rc_prr_sndcnt < segsiz)) {
12188 					/*
12189 					 * prr is less than a segment, we
12190 					 * have more acks due in besides
12191 					 * what we need to resend. Lets not send
12192 					 * to avoid sending small pieces of
12193 					 * what we need to retransmit.
12194 					 */
12195 					len = 0;
12196 					goto just_return_nolock;
12197 				}
12198 				len = rack->r_ctl.rc_prr_sndcnt;
12199 			}
12200 		}
12201 		sendalot = 0;
12202 		if (len >= segsiz)
12203 			len = segsiz;
12204 		if (len > 0) {
12205 			sub_from_prr = 1;
12206 			sack_rxmit = 1;
12207 			KMOD_TCPSTAT_INC(tcps_sack_rexmits);
12208 			KMOD_TCPSTAT_ADD(tcps_sack_rexmit_bytes,
12209 			    min(len, segsiz));
12210 			counter_u64_add(rack_rtm_prr_retran, 1);
12211 		}
12212 	} else 	if (rack->r_ctl.rc_tlpsend) {
12213 		/* Tail loss probe */
12214 		long cwin;
12215 		long tlen;
12216 
12217 		doing_tlp = 1;
12218 		/*
12219 		 * Check if we can do a TLP with a RACK'd packet
12220 		 * this can happen if we are not doing the rack
12221 		 * cheat and we skipped to a TLP and it
12222 		 * went off.
12223 		 */
12224 		rsm = rack->r_ctl.rc_tlpsend;
12225 		rsm->r_flags |= RACK_TLP;
12226 		rack->r_ctl.rc_tlpsend = NULL;
12227 		sack_rxmit = 1;
12228 		tlen = rsm->r_end - rsm->r_start;
12229 		if (tlen > segsiz)
12230 			tlen = segsiz;
12231 		KASSERT(SEQ_LEQ(tp->snd_una, rsm->r_start),
12232 			("%s:%d: r.start:%u < SND.UNA:%u; tp:%p, rack:%p, rsm:%p",
12233 			 __func__, __LINE__,
12234 			 rsm->r_start, tp->snd_una, tp, rack, rsm));
12235 		sb_offset = rsm->r_start - tp->snd_una;
12236 		cwin = min(tp->snd_wnd, tlen);
12237 		len = cwin;
12238 	}
12239 	/*
12240 	 * Enforce a connection sendmap count limit if set
12241 	 * as long as we are not retransmiting.
12242 	 */
12243 	if ((rsm == NULL) &&
12244 	    (rack->do_detection == 0) &&
12245 	    (V_tcp_map_entries_limit > 0) &&
12246 	    (rack->r_ctl.rc_num_maps_alloced >= V_tcp_map_entries_limit)) {
12247 		counter_u64_add(rack_to_alloc_limited, 1);
12248 		if (!rack->alloc_limit_reported) {
12249 			rack->alloc_limit_reported = 1;
12250 			counter_u64_add(rack_alloc_limited_conns, 1);
12251 		}
12252 		goto just_return_nolock;
12253 	}
12254 	if (rsm && (rsm->r_flags & RACK_HAS_FIN)) {
12255 		/* we are retransmitting the fin */
12256 		len--;
12257 		if (len) {
12258 			/*
12259 			 * When retransmitting data do *not* include the
12260 			 * FIN. This could happen from a TLP probe.
12261 			 */
12262 			flags &= ~TH_FIN;
12263 		}
12264 	}
12265 #ifdef INVARIANTS
12266 	/* For debugging */
12267 	rack->r_ctl.rc_rsm_at_retran = rsm;
12268 #endif
12269 	/*
12270 	 * Get standard flags, and add SYN or FIN if requested by 'hidden'
12271 	 * state flags.
12272 	 */
12273 	if (tp->t_flags & TF_NEEDFIN)
12274 		flags |= TH_FIN;
12275 	if (tp->t_flags & TF_NEEDSYN)
12276 		flags |= TH_SYN;
12277 	if ((sack_rxmit == 0) && (prefetch_rsm == 0)) {
12278 		void *end_rsm;
12279 		end_rsm = TAILQ_LAST_FAST(&rack->r_ctl.rc_tmap, rack_sendmap, r_tnext);
12280 		if (end_rsm)
12281 			kern_prefetch(end_rsm, &prefetch_rsm);
12282 		prefetch_rsm = 1;
12283 	}
12284 	SOCKBUF_LOCK(sb);
12285 	/*
12286 	 * If snd_nxt == snd_max and we have transmitted a FIN, the
12287 	 * sb_offset will be > 0 even if so_snd.sb_cc is 0, resulting in a
12288 	 * negative length.  This can also occur when TCP opens up its
12289 	 * congestion window while receiving additional duplicate acks after
12290 	 * fast-retransmit because TCP will reset snd_nxt to snd_max after
12291 	 * the fast-retransmit.
12292 	 *
12293 	 * In the normal retransmit-FIN-only case, however, snd_nxt will be
12294 	 * set to snd_una, the sb_offset will be 0, and the length may wind
12295 	 * up 0.
12296 	 *
12297 	 * If sack_rxmit is true we are retransmitting from the scoreboard
12298 	 * in which case len is already set.
12299 	 */
12300 	if ((sack_rxmit == 0) && TCPS_HAVEESTABLISHED(tp->t_state)) {
12301 		uint32_t avail;
12302 
12303 		avail = sbavail(sb);
12304 		if (SEQ_GT(tp->snd_nxt, tp->snd_una) && avail)
12305 			sb_offset = tp->snd_nxt - tp->snd_una;
12306 		else
12307 			sb_offset = 0;
12308 		if ((IN_RECOVERY(tp->t_flags) == 0) || rack->rack_no_prr) {
12309 			if (rack->r_ctl.rc_tlp_new_data) {
12310 				/* TLP is forcing out new data */
12311 				if (rack->r_ctl.rc_tlp_new_data > (uint32_t) (avail - sb_offset)) {
12312 					rack->r_ctl.rc_tlp_new_data = (uint32_t) (avail - sb_offset);
12313 				}
12314 				if (rack->r_ctl.rc_tlp_new_data > tp->snd_wnd)
12315 					len = tp->snd_wnd;
12316 				else
12317 					len = rack->r_ctl.rc_tlp_new_data;
12318 				rack->r_ctl.rc_tlp_new_data = 0;
12319 				new_data_tlp = doing_tlp = 1;
12320 			}  else
12321 				len = rack_what_can_we_send(tp, rack, cwnd_to_use, avail, sb_offset);
12322 			if (IN_RECOVERY(tp->t_flags) && (len > segsiz)) {
12323 				/*
12324 				 * For prr=off, we need to send only 1 MSS
12325 				 * at a time. We do this because another sack could
12326 				 * be arriving that causes us to send retransmits and
12327 				 * we don't want to be on a long pace due to a larger send
12328 				 * that keeps us from sending out the retransmit.
12329 				 */
12330 				len = segsiz;
12331 			}
12332 		} else {
12333 			uint32_t outstanding;
12334 
12335 			/*
12336 			 * We are inside of a SACK recovery episode and are
12337 			 * sending new data, having retransmitted all the
12338 			 * data possible so far in the scoreboard.
12339 			 */
12340 			outstanding = tp->snd_max - tp->snd_una;
12341 			if ((rack->r_ctl.rc_prr_sndcnt + outstanding) > tp->snd_wnd) {
12342 				if (tp->snd_wnd > outstanding) {
12343 					len = tp->snd_wnd - outstanding;
12344 					/* Check to see if we have the data */
12345 					if ((sb_offset + len) > avail) {
12346 						/* It does not all fit */
12347 						if (avail > sb_offset)
12348 							len = avail - sb_offset;
12349 						else
12350 							len = 0;
12351 					}
12352 				} else
12353 					len = 0;
12354 			} else if (avail > sb_offset)
12355 				len = avail - sb_offset;
12356 			else
12357 				len = 0;
12358 			if (len > 0) {
12359 				if (len > rack->r_ctl.rc_prr_sndcnt)
12360 					len = rack->r_ctl.rc_prr_sndcnt;
12361 				if (len > 0) {
12362 					sub_from_prr = 1;
12363 					counter_u64_add(rack_rtm_prr_newdata, 1);
12364 				}
12365 			}
12366 			if (len > segsiz) {
12367 				/*
12368 				 * We should never send more than a MSS when
12369 				 * retransmitting or sending new data in prr
12370 				 * mode unless the override flag is on. Most
12371 				 * likely the PRR algorithm is not going to
12372 				 * let us send a lot as well :-)
12373 				 */
12374 				if (rack->r_ctl.rc_prr_sendalot == 0)
12375 					len = segsiz;
12376 			} else if (len < segsiz) {
12377 				/*
12378 				 * Do we send any? The idea here is if the
12379 				 * send empty's the socket buffer we want to
12380 				 * do it. However if not then lets just wait
12381 				 * for our prr_sndcnt to get bigger.
12382 				 */
12383 				long leftinsb;
12384 
12385 				leftinsb = sbavail(sb) - sb_offset;
12386 				if (leftinsb > len) {
12387 					/* This send does not empty the sb */
12388 					len = 0;
12389 				}
12390 			}
12391 		}
12392 	} else if (!TCPS_HAVEESTABLISHED(tp->t_state)) {
12393 		/*
12394 		 * If you have not established
12395 		 * and are not doing FAST OPEN
12396 		 * no data please.
12397 		 */
12398 		if ((sack_rxmit == 0) &&
12399 		    (!IS_FASTOPEN(tp->t_flags))){
12400 			len = 0;
12401 			sb_offset = 0;
12402 		}
12403 	}
12404 	if (prefetch_so_done == 0) {
12405 		kern_prefetch(so, &prefetch_so_done);
12406 		prefetch_so_done = 1;
12407 	}
12408 	/*
12409 	 * Lop off SYN bit if it has already been sent.  However, if this is
12410 	 * SYN-SENT state and if segment contains data and if we don't know
12411 	 * that foreign host supports TAO, suppress sending segment.
12412 	 */
12413 	if ((flags & TH_SYN) && SEQ_GT(tp->snd_nxt, tp->snd_una) &&
12414 	    ((sack_rxmit == 0) && (tp->t_rxtshift == 0))) {
12415 		/*
12416 		 * When sending additional segments following a TFO SYN|ACK,
12417 		 * do not include the SYN bit.
12418 		 */
12419 		if (IS_FASTOPEN(tp->t_flags) &&
12420 		    (tp->t_state == TCPS_SYN_RECEIVED))
12421 			flags &= ~TH_SYN;
12422 	}
12423 	/*
12424 	 * Be careful not to send data and/or FIN on SYN segments. This
12425 	 * measure is needed to prevent interoperability problems with not
12426 	 * fully conformant TCP implementations.
12427 	 */
12428 	if ((flags & TH_SYN) && (tp->t_flags & TF_NOOPT)) {
12429 		len = 0;
12430 		flags &= ~TH_FIN;
12431 	}
12432 	/*
12433 	 * On TFO sockets, ensure no data is sent in the following cases:
12434 	 *
12435 	 *  - When retransmitting SYN|ACK on a passively-created socket
12436 	 *
12437 	 *  - When retransmitting SYN on an actively created socket
12438 	 *
12439 	 *  - When sending a zero-length cookie (cookie request) on an
12440 	 *    actively created socket
12441 	 *
12442 	 *  - When the socket is in the CLOSED state (RST is being sent)
12443 	 */
12444 	if (IS_FASTOPEN(tp->t_flags) &&
12445 	    (((flags & TH_SYN) && (tp->t_rxtshift > 0)) ||
12446 	     ((tp->t_state == TCPS_SYN_SENT) &&
12447 	      (tp->t_tfo_client_cookie_len == 0)) ||
12448 	     (flags & TH_RST))) {
12449 		sack_rxmit = 0;
12450 		len = 0;
12451 	}
12452 	/* Without fast-open there should never be data sent on a SYN */
12453 	if ((flags & TH_SYN) && (!IS_FASTOPEN(tp->t_flags))) {
12454 		tp->snd_nxt = tp->iss;
12455 		len = 0;
12456 	}
12457 	orig_len = len;
12458 	if (len <= 0) {
12459 		/*
12460 		 * If FIN has been sent but not acked, but we haven't been
12461 		 * called to retransmit, len will be < 0.  Otherwise, window
12462 		 * shrank after we sent into it.  If window shrank to 0,
12463 		 * cancel pending retransmit, pull snd_nxt back to (closed)
12464 		 * window, and set the persist timer if it isn't already
12465 		 * going.  If the window didn't close completely, just wait
12466 		 * for an ACK.
12467 		 *
12468 		 * We also do a general check here to ensure that we will
12469 		 * set the persist timer when we have data to send, but a
12470 		 * 0-byte window. This makes sure the persist timer is set
12471 		 * even if the packet hits one of the "goto send" lines
12472 		 * below.
12473 		 */
12474 		len = 0;
12475 		if ((tp->snd_wnd == 0) &&
12476 		    (TCPS_HAVEESTABLISHED(tp->t_state)) &&
12477 		    (tp->snd_una == tp->snd_max) &&
12478 		    (sb_offset < (int)sbavail(sb))) {
12479 			tp->snd_nxt = tp->snd_una;
12480 			rack_enter_persist(tp, rack, cts);
12481 		}
12482 	} else if ((rsm == NULL) &&
12483 		   ((doing_tlp == 0) || (new_data_tlp == 1)) &&
12484 		   (len < rack->r_ctl.rc_pace_max_segs)) {
12485 		/*
12486 		 * We are not sending a maximum sized segment for
12487 		 * some reason. Should we not send anything (think
12488 		 * sws or persists)?
12489 		 */
12490 		if ((tp->snd_wnd < min(max(segsiz, (rack->r_ctl.rc_high_rwnd/2)), minseg)) &&
12491 		    (TCPS_HAVEESTABLISHED(tp->t_state)) &&
12492 		    (len < minseg) &&
12493 		    (len < (int)(sbavail(sb) - sb_offset))) {
12494 			/*
12495 			 * Here the rwnd is less than
12496 			 * the minimum pacing size, this is not a retransmit,
12497 			 * we are established and
12498 			 * the send is not the last in the socket buffer
12499 			 * we send nothing, and we may enter persists
12500 			 * if nothing is outstanding.
12501 			 */
12502 			len = 0;
12503 			if (tp->snd_max == tp->snd_una) {
12504 				/*
12505 				 * Nothing out we can
12506 				 * go into persists.
12507 				 */
12508 				rack_enter_persist(tp, rack, cts);
12509 				tp->snd_nxt = tp->snd_una;
12510 			}
12511 		} else if ((cwnd_to_use >= max(minseg, (segsiz * 4))) &&
12512 			   (ctf_flight_size(tp, rack->r_ctl.rc_sacked) > (2 * segsiz)) &&
12513 			   (len < (int)(sbavail(sb) - sb_offset)) &&
12514 			   (len < minseg)) {
12515 			/*
12516 			 * Here we are not retransmitting, and
12517 			 * the cwnd is not so small that we could
12518 			 * not send at least a min size (rxt timer
12519 			 * not having gone off), We have 2 segments or
12520 			 * more already in flight, its not the tail end
12521 			 * of the socket buffer  and the cwnd is blocking
12522 			 * us from sending out a minimum pacing segment size.
12523 			 * Lets not send anything.
12524 			 */
12525 			len = 0;
12526 		} else if (((tp->snd_wnd - ctf_outstanding(tp)) <
12527 			    min((rack->r_ctl.rc_high_rwnd/2), minseg)) &&
12528 			   (ctf_flight_size(tp, rack->r_ctl.rc_sacked) > (2 * segsiz)) &&
12529 			   (len < (int)(sbavail(sb) - sb_offset)) &&
12530 			   (TCPS_HAVEESTABLISHED(tp->t_state))) {
12531 			/*
12532 			 * Here we have a send window but we have
12533 			 * filled it up and we can't send another pacing segment.
12534 			 * We also have in flight more than 2 segments
12535 			 * and we are not completing the sb i.e. we allow
12536 			 * the last bytes of the sb to go out even if
12537 			 * its not a full pacing segment.
12538 			 */
12539 			len = 0;
12540 		}
12541 	}
12542 	/* len will be >= 0 after this point. */
12543 	KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__));
12544 	tcp_sndbuf_autoscale(tp, so, min(tp->snd_wnd, cwnd_to_use));
12545 	/*
12546 	 * Decide if we can use TCP Segmentation Offloading (if supported by
12547 	 * hardware).
12548 	 *
12549 	 * TSO may only be used if we are in a pure bulk sending state.  The
12550 	 * presence of TCP-MD5, SACK retransmits, SACK advertizements and IP
12551 	 * options prevent using TSO.  With TSO the TCP header is the same
12552 	 * (except for the sequence number) for all generated packets.  This
12553 	 * makes it impossible to transmit any options which vary per
12554 	 * generated segment or packet.
12555 	 *
12556 	 * IPv4 handling has a clear separation of ip options and ip header
12557 	 * flags while IPv6 combines both in in6p_outputopts. ip6_optlen() does
12558 	 * the right thing below to provide length of just ip options and thus
12559 	 * checking for ipoptlen is enough to decide if ip options are present.
12560 	 */
12561 
12562 #ifdef INET6
12563 	if (isipv6)
12564 		ipoptlen = ip6_optlen(tp->t_inpcb);
12565 	else
12566 #endif
12567 		if (tp->t_inpcb->inp_options)
12568 			ipoptlen = tp->t_inpcb->inp_options->m_len -
12569 				offsetof(struct ipoption, ipopt_list);
12570 		else
12571 			ipoptlen = 0;
12572 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
12573 	/*
12574 	 * Pre-calculate here as we save another lookup into the darknesses
12575 	 * of IPsec that way and can actually decide if TSO is ok.
12576 	 */
12577 #ifdef INET6
12578 	if (isipv6 && IPSEC_ENABLED(ipv6))
12579 		ipsec_optlen = IPSEC_HDRSIZE(ipv6, tp->t_inpcb);
12580 #ifdef INET
12581 	else
12582 #endif
12583 #endif				/* INET6 */
12584 #ifdef INET
12585 		if (IPSEC_ENABLED(ipv4))
12586 			ipsec_optlen = IPSEC_HDRSIZE(ipv4, tp->t_inpcb);
12587 #endif				/* INET */
12588 #endif
12589 
12590 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
12591 	ipoptlen += ipsec_optlen;
12592 #endif
12593 	if ((tp->t_flags & TF_TSO) && V_tcp_do_tso && len > segsiz &&
12594 	    (tp->t_port == 0) &&
12595 	    ((tp->t_flags & TF_SIGNATURE) == 0) &&
12596 	    tp->rcv_numsacks == 0 && sack_rxmit == 0 &&
12597 	    ipoptlen == 0)
12598 		tso = 1;
12599 	{
12600 		uint32_t outstanding;
12601 
12602 		outstanding = tp->snd_max - tp->snd_una;
12603 		if (tp->t_flags & TF_SENTFIN) {
12604 			/*
12605 			 * If we sent a fin, snd_max is 1 higher than
12606 			 * snd_una
12607 			 */
12608 			outstanding--;
12609 		}
12610 		if (sack_rxmit) {
12611 			if ((rsm->r_flags & RACK_HAS_FIN) == 0)
12612 				flags &= ~TH_FIN;
12613 		} else {
12614 			if (SEQ_LT(tp->snd_nxt + len, tp->snd_una +
12615 				   sbused(sb)))
12616 				flags &= ~TH_FIN;
12617 		}
12618 	}
12619 	recwin = lmin(lmax(sbspace(&so->so_rcv), 0),
12620 	    (long)TCP_MAXWIN << tp->rcv_scale);
12621 
12622 	/*
12623 	 * Sender silly window avoidance.   We transmit under the following
12624 	 * conditions when len is non-zero:
12625 	 *
12626 	 * - We have a full segment (or more with TSO) - This is the last
12627 	 * buffer in a write()/send() and we are either idle or running
12628 	 * NODELAY - we've timed out (e.g. persist timer) - we have more
12629 	 * then 1/2 the maximum send window's worth of data (receiver may be
12630 	 * limited the window size) - we need to retransmit
12631 	 */
12632 	if (len) {
12633 		if (len >= segsiz) {
12634 			goto send;
12635 		}
12636 		/*
12637 		 * NOTE! on localhost connections an 'ack' from the remote
12638 		 * end may occur synchronously with the output and cause us
12639 		 * to flush a buffer queued with moretocome.  XXX
12640 		 *
12641 		 */
12642 		if (!(tp->t_flags & TF_MORETOCOME) &&	/* normal case */
12643 		    (idle || (tp->t_flags & TF_NODELAY)) &&
12644 		    ((uint32_t)len + (uint32_t)sb_offset >= sbavail(sb)) &&
12645 		    (tp->t_flags & TF_NOPUSH) == 0) {
12646 			pass = 2;
12647 			goto send;
12648 		}
12649 		if ((tp->snd_una == tp->snd_max) && len) {	/* Nothing outstanding */
12650 			pass = 22;
12651 			goto send;
12652 		}
12653 		if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) {
12654 			pass = 4;
12655 			goto send;
12656 		}
12657 		if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {	/* retransmit case */
12658 			pass = 5;
12659 			goto send;
12660 		}
12661 		if (sack_rxmit) {
12662 			pass = 6;
12663 			goto send;
12664 		}
12665 		if (((tp->snd_wnd - ctf_outstanding(tp)) < segsiz) &&
12666 		    (ctf_outstanding(tp) < (segsiz * 2))) {
12667 			/*
12668 			 * We have less than two MSS outstanding (delayed ack)
12669 			 * and our rwnd will not let us send a full sized
12670 			 * MSS. Lets go ahead and let this small segment
12671 			 * out because we want to try to have at least two
12672 			 * packets inflight to not be caught by delayed ack.
12673 			 */
12674 			pass = 12;
12675 			goto send;
12676 		}
12677 	}
12678 	/*
12679 	 * Sending of standalone window updates.
12680 	 *
12681 	 * Window updates are important when we close our window due to a
12682 	 * full socket buffer and are opening it again after the application
12683 	 * reads data from it.  Once the window has opened again and the
12684 	 * remote end starts to send again the ACK clock takes over and
12685 	 * provides the most current window information.
12686 	 *
12687 	 * We must avoid the silly window syndrome whereas every read from
12688 	 * the receive buffer, no matter how small, causes a window update
12689 	 * to be sent.  We also should avoid sending a flurry of window
12690 	 * updates when the socket buffer had queued a lot of data and the
12691 	 * application is doing small reads.
12692 	 *
12693 	 * Prevent a flurry of pointless window updates by only sending an
12694 	 * update when we can increase the advertized window by more than
12695 	 * 1/4th of the socket buffer capacity.  When the buffer is getting
12696 	 * full or is very small be more aggressive and send an update
12697 	 * whenever we can increase by two mss sized segments. In all other
12698 	 * situations the ACK's to new incoming data will carry further
12699 	 * window increases.
12700 	 *
12701 	 * Don't send an independent window update if a delayed ACK is
12702 	 * pending (it will get piggy-backed on it) or the remote side
12703 	 * already has done a half-close and won't send more data.  Skip
12704 	 * this if the connection is in T/TCP half-open state.
12705 	 */
12706 	if (recwin > 0 && !(tp->t_flags & TF_NEEDSYN) &&
12707 	    !(tp->t_flags & TF_DELACK) &&
12708 	    !TCPS_HAVERCVDFIN(tp->t_state)) {
12709 		/*
12710 		 * "adv" is the amount we could increase the window, taking
12711 		 * into account that we are limited by TCP_MAXWIN <<
12712 		 * tp->rcv_scale.
12713 		 */
12714 		int32_t adv;
12715 		int oldwin;
12716 
12717 		adv = recwin;
12718 		if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt)) {
12719 			oldwin = (tp->rcv_adv - tp->rcv_nxt);
12720 			if (adv > oldwin)
12721 			    adv -= oldwin;
12722 			else {
12723 				/* We can't increase the window */
12724 				adv = 0;
12725 			}
12726 		} else
12727 			oldwin = 0;
12728 
12729 		/*
12730 		 * If the new window size ends up being the same as or less
12731 		 * than the old size when it is scaled, then don't force
12732 		 * a window update.
12733 		 */
12734 		if (oldwin >> tp->rcv_scale >= (adv + oldwin) >> tp->rcv_scale)
12735 			goto dontupdate;
12736 
12737 		if (adv >= (int32_t)(2 * segsiz) &&
12738 		    (adv >= (int32_t)(so->so_rcv.sb_hiwat / 4) ||
12739 		     recwin <= (int32_t)(so->so_rcv.sb_hiwat / 8) ||
12740 		     so->so_rcv.sb_hiwat <= 8 * segsiz)) {
12741 			pass = 7;
12742 			goto send;
12743 		}
12744 		if (2 * adv >= (int32_t) so->so_rcv.sb_hiwat) {
12745 			pass = 23;
12746 			goto send;
12747 		}
12748 	}
12749 dontupdate:
12750 
12751 	/*
12752 	 * Send if we owe the peer an ACK, RST, SYN, or urgent data.  ACKNOW
12753 	 * is also a catch-all for the retransmit timer timeout case.
12754 	 */
12755 	if (tp->t_flags & TF_ACKNOW) {
12756 		pass = 8;
12757 		goto send;
12758 	}
12759 	if (((flags & TH_SYN) && (tp->t_flags & TF_NEEDSYN) == 0)) {
12760 		pass = 9;
12761 		goto send;
12762 	}
12763 	/*
12764 	 * If our state indicates that FIN should be sent and we have not
12765 	 * yet done so, then we need to send.
12766 	 */
12767 	if ((flags & TH_FIN) &&
12768 	    (tp->snd_nxt == tp->snd_una)) {
12769 		pass = 11;
12770 		goto send;
12771 	}
12772 	/*
12773 	 * No reason to send a segment, just return.
12774 	 */
12775 just_return:
12776 	SOCKBUF_UNLOCK(sb);
12777 just_return_nolock:
12778 	{
12779 		int app_limited = CTF_JR_SENT_DATA;
12780 
12781 		if (tot_len_this_send > 0) {
12782 			/* Make sure snd_nxt is up to max */
12783 			if (SEQ_GT(tp->snd_max, tp->snd_nxt))
12784 				tp->snd_nxt = tp->snd_max;
12785 			slot = rack_get_pacing_delay(rack, tp, tot_len_this_send, NULL, segsiz);
12786 		} else {
12787 			int end_window = 0;
12788 			uint32_t seq = tp->gput_ack;
12789 
12790 			rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
12791 			if (rsm) {
12792 				/*
12793 				 * Mark the last sent that we just-returned (hinting
12794 				 * that delayed ack may play a role in any rtt measurement).
12795 				 */
12796 				rsm->r_just_ret = 1;
12797 			}
12798 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_JUSTRET], 1);
12799 			rack->r_ctl.rc_agg_delayed = 0;
12800 			rack->r_early = 0;
12801 			rack->r_late = 0;
12802 			rack->r_ctl.rc_agg_early = 0;
12803 			if ((ctf_outstanding(tp) +
12804 			     min(max(segsiz, (rack->r_ctl.rc_high_rwnd/2)),
12805 				 minseg)) >= tp->snd_wnd) {
12806 				/* We are limited by the rwnd */
12807 				app_limited = CTF_JR_RWND_LIMITED;
12808 			} else if (ctf_outstanding(tp) >= sbavail(sb)) {
12809 				/* We are limited by whats available -- app limited */
12810 				app_limited = CTF_JR_APP_LIMITED;
12811 			} else if ((idle == 0) &&
12812 				   ((tp->t_flags & TF_NODELAY) == 0) &&
12813 				   ((uint32_t)len + (uint32_t)sb_offset >= sbavail(sb)) &&
12814 				   (len < segsiz)) {
12815 				/*
12816 				 * No delay is not on and the
12817 				 * user is sending less than 1MSS. This
12818 				 * brings out SWS avoidance so we
12819 				 * don't send. Another app-limited case.
12820 				 */
12821 				app_limited = CTF_JR_APP_LIMITED;
12822 			} else if (tp->t_flags & TF_NOPUSH) {
12823 				/*
12824 				 * The user has requested no push of
12825 				 * the last segment and we are
12826 				 * at the last segment. Another app
12827 				 * limited case.
12828 				 */
12829 				app_limited = CTF_JR_APP_LIMITED;
12830 			} else if ((ctf_outstanding(tp) + minseg) > cwnd_to_use) {
12831 				/* Its the cwnd */
12832 				app_limited = CTF_JR_CWND_LIMITED;
12833 			} else if (rack->rc_in_persist == 1) {
12834 				/* We are in persists */
12835 				app_limited = CTF_JR_PERSISTS;
12836 			} else if (IN_RECOVERY(tp->t_flags) &&
12837 				   (rack->rack_no_prr == 0) &&
12838 				   (rack->r_ctl.rc_prr_sndcnt < segsiz)) {
12839 				app_limited = CTF_JR_PRR;
12840 			} else {
12841 				/* Now why here are we not sending? */
12842 #ifdef NOW
12843 #ifdef INVARIANTS
12844 				panic("rack:%p hit JR_ASSESSING case cwnd_to_use:%u?", rack, cwnd_to_use);
12845 #endif
12846 #endif
12847 				app_limited = CTF_JR_ASSESSING;
12848 			}
12849 			/*
12850 			 * App limited in some fashion, for our pacing GP
12851 			 * measurements we don't want any gap (even cwnd).
12852 			 * Close  down the measurement window.
12853 			 */
12854 			if (rack_cwnd_block_ends_measure &&
12855 			    ((app_limited == CTF_JR_CWND_LIMITED) ||
12856 			     (app_limited == CTF_JR_PRR))) {
12857 				/*
12858 				 * The reason we are not sending is
12859 				 * the cwnd (or prr). We have been configured
12860 				 * to end the measurement window in
12861 				 * this case.
12862 				 */
12863 				end_window = 1;
12864 			} else if (app_limited == CTF_JR_PERSISTS) {
12865 				/*
12866 				 * We never end the measurement window
12867 				 * in persists, though in theory we
12868 				 * should be only entering after everything
12869 				 * is acknowledged (so we will probably
12870 				 * never come here).
12871 				 */
12872 				end_window = 0;
12873 			} else if (rack_rwnd_block_ends_measure &&
12874 				   (app_limited == CTF_JR_RWND_LIMITED)) {
12875 				/*
12876 				 * We are rwnd limited and have been
12877 				 * configured to end the measurement
12878 				 * window in this case.
12879 				 */
12880 				end_window = 1;
12881 			} else if (app_limited == CTF_JR_APP_LIMITED) {
12882 				/*
12883 				 * A true application limited period, we have
12884 				 * ran out of data.
12885 				 */
12886 				end_window = 1;
12887 			} else if (app_limited == CTF_JR_ASSESSING) {
12888 				/*
12889 				 * In the assessing case we hit the end of
12890 				 * the if/else and had no known reason
12891 				 * This will panic us under invariants..
12892 				 *
12893 				 * If we get this out in logs we need to
12894 				 * investagate which reason we missed.
12895 				 */
12896 				end_window = 1;
12897 			}
12898 			if (end_window) {
12899 				uint8_t log = 0;
12900 
12901 				if ((tp->t_flags & TF_GPUTINPROG) &&
12902 				    SEQ_GT(tp->gput_ack, tp->snd_max)) {
12903 					/* Mark the last packet has app limited */
12904 					tp->gput_ack = tp->snd_max;
12905 					log = 1;
12906 				}
12907 				rsm = RB_MAX(rack_rb_tree_head, &rack->r_ctl.rc_mtree);
12908 				if (rsm && ((rsm->r_flags & RACK_APP_LIMITED) == 0)) {
12909 					if (rack->r_ctl.rc_app_limited_cnt == 0)
12910 						rack->r_ctl.rc_end_appl = rack->r_ctl.rc_first_appl = rsm;
12911 					else {
12912 						/*
12913 						 * Go out to the end app limited and mark
12914 						 * this new one as next and move the end_appl up
12915 						 * to this guy.
12916 						 */
12917 						if (rack->r_ctl.rc_end_appl)
12918 							rack->r_ctl.rc_end_appl->r_nseq_appl = rsm->r_start;
12919 						rack->r_ctl.rc_end_appl = rsm;
12920 					}
12921 					rsm->r_flags |= RACK_APP_LIMITED;
12922 					rack->r_ctl.rc_app_limited_cnt++;
12923 				}
12924 				if (log)
12925 					rack_log_pacing_delay_calc(rack,
12926 								   rack->r_ctl.rc_app_limited_cnt, seq,
12927 								   tp->gput_ack, 0, 0, 4, __LINE__, NULL);
12928 			}
12929 		}
12930 		if (slot) {
12931 			/* set the rack tcb into the slot N */
12932 			counter_u64_add(rack_paced_segments, 1);
12933 		} else if (tot_len_this_send) {
12934 			counter_u64_add(rack_unpaced_segments, 1);
12935 		}
12936 		/* Check if we need to go into persists or not */
12937 		if ((rack->rc_in_persist == 0) &&
12938 		    (tp->snd_max == tp->snd_una) &&
12939 		    TCPS_HAVEESTABLISHED(tp->t_state) &&
12940 		    sbavail(sb) &&
12941 		    (sbavail(sb) > tp->snd_wnd) &&
12942 		    (tp->snd_wnd < min((rack->r_ctl.rc_high_rwnd/2), minseg))) {
12943 			/* Yes lets make sure to move to persist before timer-start */
12944 			rack_enter_persist(tp, rack, rack->r_ctl.rc_rcvtime);
12945 		}
12946 		rack_start_hpts_timer(rack, tp, cts, slot, tot_len_this_send, sup_rack);
12947 		rack_log_type_just_return(rack, cts, tot_len_this_send, slot, hpts_calling, app_limited, cwnd_to_use);
12948 	}
12949 #ifdef NETFLIX_SHARED_CWND
12950 	if ((sbavail(sb) == 0) &&
12951 	    rack->r_ctl.rc_scw) {
12952 		tcp_shared_cwnd_idle(rack->r_ctl.rc_scw, rack->r_ctl.rc_scw_index);
12953 		rack->rack_scwnd_is_idle = 1;
12954 	}
12955 #endif
12956 	return (0);
12957 
12958 send:
12959 	if ((flags & TH_FIN) &&
12960 	    sbavail(sb)) {
12961 		/*
12962 		 * We do not transmit a FIN
12963 		 * with data outstanding. We
12964 		 * need to make it so all data
12965 		 * is acked first.
12966 		 */
12967 		flags &= ~TH_FIN;
12968 	}
12969 	/* Enforce stack imposed max seg size if we have one */
12970 	if (rack->r_ctl.rc_pace_max_segs &&
12971 	    (len > rack->r_ctl.rc_pace_max_segs)) {
12972 		mark = 1;
12973 		len = rack->r_ctl.rc_pace_max_segs;
12974 	}
12975 	SOCKBUF_LOCK_ASSERT(sb);
12976 	if (len > 0) {
12977 		if (len >= segsiz)
12978 			tp->t_flags2 |= TF2_PLPMTU_MAXSEGSNT;
12979 		else
12980 			tp->t_flags2 &= ~TF2_PLPMTU_MAXSEGSNT;
12981 	}
12982 	/*
12983 	 * Before ESTABLISHED, force sending of initial options unless TCP
12984 	 * set not to do any options. NOTE: we assume that the IP/TCP header
12985 	 * plus TCP options always fit in a single mbuf, leaving room for a
12986 	 * maximum link header, i.e. max_linkhdr + sizeof (struct tcpiphdr)
12987 	 * + optlen <= MCLBYTES
12988 	 */
12989 	optlen = 0;
12990 #ifdef INET6
12991 	if (isipv6)
12992 		hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
12993 	else
12994 #endif
12995 		hdrlen = sizeof(struct tcpiphdr);
12996 
12997 	/*
12998 	 * Compute options for segment. We only have to care about SYN and
12999 	 * established connection segments.  Options for SYN-ACK segments
13000 	 * are handled in TCP syncache.
13001 	 */
13002 	to.to_flags = 0;
13003 	if ((tp->t_flags & TF_NOOPT) == 0) {
13004 		/* Maximum segment size. */
13005 		if (flags & TH_SYN) {
13006 			tp->snd_nxt = tp->iss;
13007 			to.to_mss = tcp_mssopt(&inp->inp_inc);
13008 #ifdef NETFLIX_TCPOUDP
13009 			if (tp->t_port)
13010 				to.to_mss -= V_tcp_udp_tunneling_overhead;
13011 #endif
13012 			to.to_flags |= TOF_MSS;
13013 
13014 			/*
13015 			 * On SYN or SYN|ACK transmits on TFO connections,
13016 			 * only include the TFO option if it is not a
13017 			 * retransmit, as the presence of the TFO option may
13018 			 * have caused the original SYN or SYN|ACK to have
13019 			 * been dropped by a middlebox.
13020 			 */
13021 			if (IS_FASTOPEN(tp->t_flags) &&
13022 			    (tp->t_rxtshift == 0)) {
13023 				if (tp->t_state == TCPS_SYN_RECEIVED) {
13024 					to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN;
13025 					to.to_tfo_cookie =
13026 						(u_int8_t *)&tp->t_tfo_cookie.server;
13027 					to.to_flags |= TOF_FASTOPEN;
13028 					wanted_cookie = 1;
13029 				} else if (tp->t_state == TCPS_SYN_SENT) {
13030 					to.to_tfo_len =
13031 						tp->t_tfo_client_cookie_len;
13032 					to.to_tfo_cookie =
13033 						tp->t_tfo_cookie.client;
13034 					to.to_flags |= TOF_FASTOPEN;
13035 					wanted_cookie = 1;
13036 					/*
13037 					 * If we wind up having more data to
13038 					 * send with the SYN than can fit in
13039 					 * one segment, don't send any more
13040 					 * until the SYN|ACK comes back from
13041 					 * the other end.
13042 					 */
13043 					sendalot = 0;
13044 				}
13045 			}
13046 		}
13047 		/* Window scaling. */
13048 		if ((flags & TH_SYN) && (tp->t_flags & TF_REQ_SCALE)) {
13049 			to.to_wscale = tp->request_r_scale;
13050 			to.to_flags |= TOF_SCALE;
13051 		}
13052 		/* Timestamps. */
13053 		if ((tp->t_flags & TF_RCVD_TSTMP) ||
13054 		    ((flags & TH_SYN) && (tp->t_flags & TF_REQ_TSTMP))) {
13055 			to.to_tsval = cts + tp->ts_offset;
13056 			to.to_tsecr = tp->ts_recent;
13057 			to.to_flags |= TOF_TS;
13058 		}
13059 		/* Set receive buffer autosizing timestamp. */
13060 		if (tp->rfbuf_ts == 0 &&
13061 		    (so->so_rcv.sb_flags & SB_AUTOSIZE))
13062 			tp->rfbuf_ts = tcp_ts_getticks();
13063 		/* Selective ACK's. */
13064 		if (flags & TH_SYN)
13065 			to.to_flags |= TOF_SACKPERM;
13066 		else if (TCPS_HAVEESTABLISHED(tp->t_state) &&
13067 			 tp->rcv_numsacks > 0) {
13068 			to.to_flags |= TOF_SACK;
13069 			to.to_nsacks = tp->rcv_numsacks;
13070 			to.to_sacks = (u_char *)tp->sackblks;
13071 		}
13072 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
13073 		/* TCP-MD5 (RFC2385). */
13074 		if (tp->t_flags & TF_SIGNATURE)
13075 			to.to_flags |= TOF_SIGNATURE;
13076 #endif				/* TCP_SIGNATURE */
13077 
13078 		/* Processing the options. */
13079 		hdrlen += optlen = tcp_addoptions(&to, opt);
13080 		/*
13081 		 * If we wanted a TFO option to be added, but it was unable
13082 		 * to fit, ensure no data is sent.
13083 		 */
13084 		if (IS_FASTOPEN(tp->t_flags) && wanted_cookie &&
13085 		    !(to.to_flags & TOF_FASTOPEN))
13086 			len = 0;
13087 	}
13088 #ifdef NETFLIX_TCPOUDP
13089 	if (tp->t_port) {
13090 		if (V_tcp_udp_tunneling_port == 0) {
13091 			/* The port was removed?? */
13092 			SOCKBUF_UNLOCK(&so->so_snd);
13093 			return (EHOSTUNREACH);
13094 		}
13095 		hdrlen += sizeof(struct udphdr);
13096 	}
13097 #endif
13098 #ifdef INET6
13099 	if (isipv6)
13100 		ipoptlen = ip6_optlen(tp->t_inpcb);
13101 	else
13102 #endif
13103 		if (tp->t_inpcb->inp_options)
13104 			ipoptlen = tp->t_inpcb->inp_options->m_len -
13105 				offsetof(struct ipoption, ipopt_list);
13106 		else
13107 			ipoptlen = 0;
13108 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
13109 	ipoptlen += ipsec_optlen;
13110 #endif
13111 
13112 	/*
13113 	 * Adjust data length if insertion of options will bump the packet
13114 	 * length beyond the t_maxseg length. Clear the FIN bit because we
13115 	 * cut off the tail of the segment.
13116 	 */
13117 	if (len + optlen + ipoptlen > tp->t_maxseg) {
13118 		if (tso) {
13119 			uint32_t if_hw_tsomax;
13120 			uint32_t moff;
13121 			int32_t max_len;
13122 
13123 			/* extract TSO information */
13124 			if_hw_tsomax = tp->t_tsomax;
13125 			if_hw_tsomaxsegcount = tp->t_tsomaxsegcount;
13126 			if_hw_tsomaxsegsize = tp->t_tsomaxsegsize;
13127 			KASSERT(ipoptlen == 0,
13128 				("%s: TSO can't do IP options", __func__));
13129 
13130 			/*
13131 			 * Check if we should limit by maximum payload
13132 			 * length:
13133 			 */
13134 			if (if_hw_tsomax != 0) {
13135 				/* compute maximum TSO length */
13136 				max_len = (if_hw_tsomax - hdrlen -
13137 					   max_linkhdr);
13138 				if (max_len <= 0) {
13139 					len = 0;
13140 				} else if (len > max_len) {
13141 					sendalot = 1;
13142 					len = max_len;
13143 					mark = 2;
13144 				}
13145 			}
13146 			/*
13147 			 * Prevent the last segment from being fractional
13148 			 * unless the send sockbuf can be emptied:
13149 			 */
13150 			max_len = (tp->t_maxseg - optlen);
13151 			if ((sb_offset + len) < sbavail(sb)) {
13152 				moff = len % (u_int)max_len;
13153 				if (moff != 0) {
13154 					mark = 3;
13155 					len -= moff;
13156 				}
13157 			}
13158                         /*
13159 			 * In case there are too many small fragments don't
13160 			 * use TSO:
13161 			 */
13162 			if (len <= segsiz) {
13163 				mark = 4;
13164 				tso = 0;
13165 			}
13166 			/*
13167 			 * Send the FIN in a separate segment after the bulk
13168 			 * sending is done. We don't trust the TSO
13169 			 * implementations to clear the FIN flag on all but
13170 			 * the last segment.
13171 			 */
13172 			if (tp->t_flags & TF_NEEDFIN) {
13173 				sendalot = 4;
13174 			}
13175 		} else {
13176 			mark = 5;
13177 			if (optlen + ipoptlen >= tp->t_maxseg) {
13178 				/*
13179 				 * Since we don't have enough space to put
13180 				 * the IP header chain and the TCP header in
13181 				 * one packet as required by RFC 7112, don't
13182 				 * send it. Also ensure that at least one
13183 				 * byte of the payload can be put into the
13184 				 * TCP segment.
13185 				 */
13186 				SOCKBUF_UNLOCK(&so->so_snd);
13187 				error = EMSGSIZE;
13188 				sack_rxmit = 0;
13189 				goto out;
13190 			}
13191 			len = tp->t_maxseg - optlen - ipoptlen;
13192 			sendalot = 5;
13193 		}
13194 	} else {
13195 		tso = 0;
13196 		mark = 6;
13197 	}
13198 	KASSERT(len + hdrlen + ipoptlen <= IP_MAXPACKET,
13199 		("%s: len > IP_MAXPACKET", __func__));
13200 #ifdef DIAGNOSTIC
13201 #ifdef INET6
13202 	if (max_linkhdr + hdrlen > MCLBYTES)
13203 #else
13204 		if (max_linkhdr + hdrlen > MHLEN)
13205 #endif
13206 			panic("tcphdr too big");
13207 #endif
13208 
13209 	/*
13210 	 * This KASSERT is here to catch edge cases at a well defined place.
13211 	 * Before, those had triggered (random) panic conditions further
13212 	 * down.
13213 	 */
13214 	KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__));
13215 	if ((len == 0) &&
13216 	    (flags & TH_FIN) &&
13217 	    (sbused(sb))) {
13218 		/*
13219 		 * We have outstanding data, don't send a fin by itself!.
13220 		 */
13221 		goto just_return;
13222 	}
13223 	/*
13224 	 * Grab a header mbuf, attaching a copy of data to be transmitted,
13225 	 * and initialize the header from the template for sends on this
13226 	 * connection.
13227 	 */
13228 	if (len) {
13229 		uint32_t max_val;
13230 		uint32_t moff;
13231 
13232 		if (rack->r_ctl.rc_pace_max_segs)
13233 			max_val = rack->r_ctl.rc_pace_max_segs;
13234 		else if (rack->rc_user_set_max_segs)
13235 			max_val = rack->rc_user_set_max_segs * segsiz;
13236 		else
13237 			max_val = len;
13238 		/*
13239 		 * We allow a limit on sending with hptsi.
13240 		 */
13241 		if (len > max_val) {
13242 			mark = 7;
13243 			len = max_val;
13244 		}
13245 #ifdef INET6
13246 		if (MHLEN < hdrlen + max_linkhdr)
13247 			m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
13248 		else
13249 #endif
13250 			m = m_gethdr(M_NOWAIT, MT_DATA);
13251 
13252 		if (m == NULL) {
13253 			SOCKBUF_UNLOCK(sb);
13254 			error = ENOBUFS;
13255 			sack_rxmit = 0;
13256 			goto out;
13257 		}
13258 		m->m_data += max_linkhdr;
13259 		m->m_len = hdrlen;
13260 
13261 		/*
13262 		 * Start the m_copy functions from the closest mbuf to the
13263 		 * sb_offset in the socket buffer chain.
13264 		 */
13265 		mb = sbsndptr_noadv(sb, sb_offset, &moff);
13266 		if (len <= MHLEN - hdrlen - max_linkhdr && !hw_tls) {
13267 			m_copydata(mb, moff, (int)len,
13268 				   mtod(m, caddr_t)+hdrlen);
13269 			if (SEQ_LT(tp->snd_nxt, tp->snd_max))
13270 				sbsndptr_adv(sb, mb, len);
13271 			m->m_len += len;
13272 		} else {
13273 			struct sockbuf *msb;
13274 
13275 			if (SEQ_LT(tp->snd_nxt, tp->snd_max))
13276 				msb = NULL;
13277 			else
13278 				msb = sb;
13279 			m->m_next = tcp_m_copym(
13280 				mb, moff, &len,
13281 				if_hw_tsomaxsegcount, if_hw_tsomaxsegsize, msb,
13282 				((rsm == NULL) ? hw_tls : 0)
13283 #ifdef NETFLIX_COPY_ARGS
13284 				, &filled_all
13285 #endif
13286 				);
13287 			if (len <= (tp->t_maxseg - optlen)) {
13288 				/*
13289 				 * Must have ran out of mbufs for the copy
13290 				 * shorten it to no longer need tso. Lets
13291 				 * not put on sendalot since we are low on
13292 				 * mbufs.
13293 				 */
13294 				tso = 0;
13295 			}
13296 			if (m->m_next == NULL) {
13297 				SOCKBUF_UNLOCK(sb);
13298 				(void)m_free(m);
13299 				error = ENOBUFS;
13300 				sack_rxmit = 0;
13301 				goto out;
13302 			}
13303 		}
13304 		if (SEQ_LT(tp->snd_nxt, tp->snd_max) || sack_rxmit) {
13305 			if (rsm && (rsm->r_flags & RACK_TLP)) {
13306 				/*
13307 				 * TLP should not count in retran count, but
13308 				 * in its own bin
13309 				 */
13310 				counter_u64_add(rack_tlp_retran, 1);
13311 				counter_u64_add(rack_tlp_retran_bytes, len);
13312 			} else {
13313 				tp->t_sndrexmitpack++;
13314 				KMOD_TCPSTAT_INC(tcps_sndrexmitpack);
13315 				KMOD_TCPSTAT_ADD(tcps_sndrexmitbyte, len);
13316 			}
13317 #ifdef STATS
13318 			stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RETXPB,
13319 						 len);
13320 #endif
13321 		} else {
13322 			KMOD_TCPSTAT_INC(tcps_sndpack);
13323 			KMOD_TCPSTAT_ADD(tcps_sndbyte, len);
13324 #ifdef STATS
13325 			stats_voi_update_abs_u64(tp->t_stats, VOI_TCP_TXPB,
13326 						 len);
13327 #endif
13328 		}
13329 		/*
13330 		 * If we're sending everything we've got, set PUSH. (This
13331 		 * will keep happy those implementations which only give
13332 		 * data to the user when a buffer fills or a PUSH comes in.)
13333 		 */
13334 		if (sb_offset + len == sbused(sb) &&
13335 		    sbused(sb) &&
13336 		    !(flags & TH_SYN))
13337 			flags |= TH_PUSH;
13338 
13339 		SOCKBUF_UNLOCK(sb);
13340 	} else {
13341 		SOCKBUF_UNLOCK(sb);
13342 		if (tp->t_flags & TF_ACKNOW)
13343 			KMOD_TCPSTAT_INC(tcps_sndacks);
13344 		else if (flags & (TH_SYN | TH_FIN | TH_RST))
13345 			KMOD_TCPSTAT_INC(tcps_sndctrl);
13346 		else
13347 			KMOD_TCPSTAT_INC(tcps_sndwinup);
13348 
13349 		m = m_gethdr(M_NOWAIT, MT_DATA);
13350 		if (m == NULL) {
13351 			error = ENOBUFS;
13352 			sack_rxmit = 0;
13353 			goto out;
13354 		}
13355 #ifdef INET6
13356 		if (isipv6 && (MHLEN < hdrlen + max_linkhdr) &&
13357 		    MHLEN >= hdrlen) {
13358 			M_ALIGN(m, hdrlen);
13359 		} else
13360 #endif
13361 			m->m_data += max_linkhdr;
13362 		m->m_len = hdrlen;
13363 	}
13364 	SOCKBUF_UNLOCK_ASSERT(sb);
13365 	m->m_pkthdr.rcvif = (struct ifnet *)0;
13366 #ifdef MAC
13367 	mac_inpcb_create_mbuf(inp, m);
13368 #endif
13369 #ifdef INET6
13370 	if (isipv6) {
13371 		ip6 = mtod(m, struct ip6_hdr *);
13372 #ifdef NETFLIX_TCPOUDP
13373 		if (tp->t_port) {
13374 			udp = (struct udphdr *)((caddr_t)ip6 + ipoptlen + sizeof(struct ip6_hdr));
13375 			udp->uh_sport = htons(V_tcp_udp_tunneling_port);
13376 			udp->uh_dport = tp->t_port;
13377 			ulen = hdrlen + len - sizeof(struct ip6_hdr);
13378 			udp->uh_ulen = htons(ulen);
13379 			th = (struct tcphdr *)(udp + 1);
13380 		} else
13381 #endif
13382 			th = (struct tcphdr *)(ip6 + 1);
13383 		tcpip_fillheaders(inp,
13384 #ifdef NETFLIX_TCPOUDP
13385 				  tp->t_port,
13386 #endif
13387 				  ip6, th);
13388 	} else
13389 #endif				/* INET6 */
13390 	{
13391 		ip = mtod(m, struct ip *);
13392 #ifdef TCPDEBUG
13393 		ipov = (struct ipovly *)ip;
13394 #endif
13395 #ifdef NETFLIX_TCPOUDP
13396 		if (tp->t_port) {
13397 			udp = (struct udphdr *)((caddr_t)ip + ipoptlen + sizeof(struct ip));
13398 			udp->uh_sport = htons(V_tcp_udp_tunneling_port);
13399 			udp->uh_dport = tp->t_port;
13400 			ulen = hdrlen + len - sizeof(struct ip);
13401 			udp->uh_ulen = htons(ulen);
13402 			th = (struct tcphdr *)(udp + 1);
13403 		} else
13404 #endif
13405 			th = (struct tcphdr *)(ip + 1);
13406 		tcpip_fillheaders(inp,
13407 #ifdef NETFLIX_TCPOUDP
13408 				  tp->t_port,
13409 #endif
13410 				  ip, th);
13411 	}
13412 	/*
13413 	 * Fill in fields, remembering maximum advertised window for use in
13414 	 * delaying messages about window sizes. If resending a FIN, be sure
13415 	 * not to use a new sequence number.
13416 	 */
13417 	if (flags & TH_FIN && tp->t_flags & TF_SENTFIN &&
13418 	    tp->snd_nxt == tp->snd_max)
13419 		tp->snd_nxt--;
13420 	/*
13421 	 * If we are starting a connection, send ECN setup SYN packet. If we
13422 	 * are on a retransmit, we may resend those bits a number of times
13423 	 * as per RFC 3168.
13424 	 */
13425 	if (tp->t_state == TCPS_SYN_SENT && V_tcp_do_ecn == 1) {
13426 		if (tp->t_rxtshift >= 1) {
13427 			if (tp->t_rxtshift <= V_tcp_ecn_maxretries)
13428 				flags |= TH_ECE | TH_CWR;
13429 		} else
13430 			flags |= TH_ECE | TH_CWR;
13431 	}
13432 	/* Handle parallel SYN for ECN */
13433 	if ((tp->t_state == TCPS_SYN_RECEIVED) &&
13434 	    (tp->t_flags2 & TF2_ECN_SND_ECE)) {
13435 		flags |= TH_ECE;
13436 		tp->t_flags2 &= ~TF2_ECN_SND_ECE;
13437 	}
13438 	if (tp->t_state == TCPS_ESTABLISHED &&
13439 	    (tp->t_flags2 & TF2_ECN_PERMIT)) {
13440 		/*
13441 		 * If the peer has ECN, mark data packets with ECN capable
13442 		 * transmission (ECT). Ignore pure ack packets,
13443 		 * retransmissions.
13444 		 */
13445 		if (len > 0 && SEQ_GEQ(tp->snd_nxt, tp->snd_max) &&
13446 		    (sack_rxmit == 0)) {
13447 #ifdef INET6
13448 			if (isipv6)
13449 				ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20);
13450 			else
13451 #endif
13452 				ip->ip_tos |= IPTOS_ECN_ECT0;
13453 			KMOD_TCPSTAT_INC(tcps_ecn_ect0);
13454 			/*
13455 			 * Reply with proper ECN notifications.
13456 			 * Only set CWR on new data segments.
13457 			 */
13458 			if (tp->t_flags2 & TF2_ECN_SND_CWR) {
13459 				flags |= TH_CWR;
13460 				tp->t_flags2 &= ~TF2_ECN_SND_CWR;
13461 			}
13462 		}
13463 		if (tp->t_flags2 & TF2_ECN_SND_ECE)
13464 			flags |= TH_ECE;
13465 	}
13466 	/*
13467 	 * If we are doing retransmissions, then snd_nxt will not reflect
13468 	 * the first unsent octet.  For ACK only packets, we do not want the
13469 	 * sequence number of the retransmitted packet, we want the sequence
13470 	 * number of the next unsent octet.  So, if there is no data (and no
13471 	 * SYN or FIN), use snd_max instead of snd_nxt when filling in
13472 	 * ti_seq.  But if we are in persist state, snd_max might reflect
13473 	 * one byte beyond the right edge of the window, so use snd_nxt in
13474 	 * that case, since we know we aren't doing a retransmission.
13475 	 * (retransmit and persist are mutually exclusive...)
13476 	 */
13477 	if (sack_rxmit == 0) {
13478 		if (len || (flags & (TH_SYN | TH_FIN)) ||
13479 		    rack->rc_in_persist) {
13480 			th->th_seq = htonl(tp->snd_nxt);
13481 			rack_seq = tp->snd_nxt;
13482 		} else if (flags & TH_RST) {
13483 			/*
13484 			 * For a Reset send the last cum ack in sequence
13485 			 * (this like any other choice may still generate a
13486 			 * challenge ack, if a ack-update packet is in
13487 			 * flight).
13488 			 */
13489 			th->th_seq = htonl(tp->snd_una);
13490 			rack_seq = tp->snd_una;
13491 		} else {
13492 			th->th_seq = htonl(tp->snd_max);
13493 			rack_seq = tp->snd_max;
13494 		}
13495 	} else {
13496 		th->th_seq = htonl(rsm->r_start);
13497 		rack_seq = rsm->r_start;
13498 	}
13499 	th->th_ack = htonl(tp->rcv_nxt);
13500 	if (optlen) {
13501 		bcopy(opt, th + 1, optlen);
13502 		th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
13503 	}
13504 	th->th_flags = flags;
13505 	/*
13506 	 * Calculate receive window.  Don't shrink window, but avoid silly
13507 	 * window syndrome.
13508 	 * If a RST segment is sent, advertise a window of zero.
13509 	 */
13510 	if (flags & TH_RST) {
13511 		recwin = 0;
13512 	} else {
13513 		if (recwin < (long)(so->so_rcv.sb_hiwat / 4) &&
13514 		    recwin < (long)segsiz)
13515 			recwin = 0;
13516 		if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt) &&
13517 		    recwin < (long)(tp->rcv_adv - tp->rcv_nxt))
13518 			recwin = (long)(tp->rcv_adv - tp->rcv_nxt);
13519 	}
13520 
13521 	/*
13522 	 * According to RFC1323 the window field in a SYN (i.e., a <SYN> or
13523 	 * <SYN,ACK>) segment itself is never scaled.  The <SYN,ACK> case is
13524 	 * handled in syncache.
13525 	 */
13526 	if (flags & TH_SYN)
13527 		th->th_win = htons((u_short)
13528 				   (min(sbspace(&so->so_rcv), TCP_MAXWIN)));
13529 	else {
13530 		/* Avoid shrinking window with window scaling. */
13531 		recwin = roundup2(recwin, 1 << tp->rcv_scale);
13532 		th->th_win = htons((u_short)(recwin >> tp->rcv_scale));
13533 	}
13534 	/*
13535 	 * Adjust the RXWIN0SENT flag - indicate that we have advertised a 0
13536 	 * window.  This may cause the remote transmitter to stall.  This
13537 	 * flag tells soreceive() to disable delayed acknowledgements when
13538 	 * draining the buffer.  This can occur if the receiver is
13539 	 * attempting to read more data than can be buffered prior to
13540 	 * transmitting on the connection.
13541 	 */
13542 	if (th->th_win == 0) {
13543 		tp->t_sndzerowin++;
13544 		tp->t_flags |= TF_RXWIN0SENT;
13545 	} else
13546 		tp->t_flags &= ~TF_RXWIN0SENT;
13547 	tp->snd_up = tp->snd_una;	/* drag it along, its deprecated  */
13548 
13549 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
13550 	if (to.to_flags & TOF_SIGNATURE) {
13551 		/*
13552 		 * Calculate MD5 signature and put it into the place
13553 		 * determined before.
13554 		 * NOTE: since TCP options buffer doesn't point into
13555 		 * mbuf's data, calculate offset and use it.
13556 		 */
13557 		if (!TCPMD5_ENABLED() || TCPMD5_OUTPUT(m, th,
13558 						       (u_char *)(th + 1) + (to.to_signature - opt)) != 0) {
13559 			/*
13560 			 * Do not send segment if the calculation of MD5
13561 			 * digest has failed.
13562 			 */
13563 			goto out;
13564 		}
13565 	}
13566 #endif
13567 
13568 	/*
13569 	 * Put TCP length in extended header, and then checksum extended
13570 	 * header and data.
13571 	 */
13572 	m->m_pkthdr.len = hdrlen + len;	/* in6_cksum() need this */
13573 #ifdef INET6
13574 	if (isipv6) {
13575 		/*
13576 		 * ip6_plen is not need to be filled now, and will be filled
13577 		 * in ip6_output.
13578 		 */
13579 		if (tp->t_port) {
13580 			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
13581 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
13582 			udp->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0);
13583 			th->th_sum = htons(0);
13584 			UDPSTAT_INC(udps_opackets);
13585 		} else {
13586 			m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
13587 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
13588 			th->th_sum = in6_cksum_pseudo(ip6,
13589 						      sizeof(struct tcphdr) + optlen + len, IPPROTO_TCP,
13590 						      0);
13591 		}
13592 	}
13593 #endif
13594 #if defined(INET6) && defined(INET)
13595 	else
13596 #endif
13597 #ifdef INET
13598 	{
13599 		if (tp->t_port) {
13600 			m->m_pkthdr.csum_flags = CSUM_UDP;
13601 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
13602 			udp->uh_sum = in_pseudo(ip->ip_src.s_addr,
13603 						ip->ip_dst.s_addr, htons(ulen + IPPROTO_UDP));
13604 			th->th_sum = htons(0);
13605 			UDPSTAT_INC(udps_opackets);
13606 		} else {
13607 			m->m_pkthdr.csum_flags = CSUM_TCP;
13608 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
13609 			th->th_sum = in_pseudo(ip->ip_src.s_addr,
13610 					       ip->ip_dst.s_addr, htons(sizeof(struct tcphdr) +
13611 									IPPROTO_TCP + len + optlen));
13612 		}
13613 		/* IP version must be set here for ipv4/ipv6 checking later */
13614 		KASSERT(ip->ip_v == IPVERSION,
13615 			("%s: IP version incorrect: %d", __func__, ip->ip_v));
13616 	}
13617 #endif
13618 	/*
13619 	 * Enable TSO and specify the size of the segments. The TCP pseudo
13620 	 * header checksum is always provided. XXX: Fixme: This is currently
13621 	 * not the case for IPv6.
13622 	 */
13623 	if (tso) {
13624 		KASSERT(len > tp->t_maxseg - optlen,
13625 			("%s: len <= tso_segsz", __func__));
13626 		m->m_pkthdr.csum_flags |= CSUM_TSO;
13627 		m->m_pkthdr.tso_segsz = tp->t_maxseg - optlen;
13628 	}
13629 	KASSERT(len + hdrlen == m_length(m, NULL),
13630 		("%s: mbuf chain different than expected: %d + %u != %u",
13631 		 __func__, len, hdrlen, m_length(m, NULL)));
13632 
13633 #ifdef TCP_HHOOK
13634 	/* Run HHOOK_TCP_ESTABLISHED_OUT helper hooks. */
13635 	hhook_run_tcp_est_out(tp, th, &to, len, tso);
13636 #endif
13637 #ifdef TCPDEBUG
13638 	/*
13639 	 * Trace.
13640 	 */
13641 	if (so->so_options & SO_DEBUG) {
13642 		u_short save = 0;
13643 
13644 #ifdef INET6
13645 		if (!isipv6)
13646 #endif
13647 		{
13648 			save = ipov->ih_len;
13649 			ipov->ih_len = htons(m->m_pkthdr.len	/* - hdrlen +
13650 								 * (th->th_off << 2) */ );
13651 		}
13652 		tcp_trace(TA_OUTPUT, tp->t_state, tp, mtod(m, void *), th, 0);
13653 #ifdef INET6
13654 		if (!isipv6)
13655 #endif
13656 			ipov->ih_len = save;
13657 	}
13658 #endif				/* TCPDEBUG */
13659 
13660 	/* We're getting ready to send; log now. */
13661 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
13662 		union tcp_log_stackspecific log;
13663 		struct timeval tv;
13664 
13665 		memset(&log.u_bbr, 0, sizeof(log.u_bbr));
13666 		log.u_bbr.inhpts = rack->rc_inp->inp_in_hpts;
13667 		log.u_bbr.ininput = rack->rc_inp->inp_in_input;
13668 		if (rack->rack_no_prr)
13669 			log.u_bbr.flex1 = 0;
13670 		else
13671 			log.u_bbr.flex1 = rack->r_ctl.rc_prr_sndcnt;
13672 		log.u_bbr.flex2 = rack->r_ctl.rc_pace_min_segs;
13673 		log.u_bbr.flex3 = rack->r_ctl.rc_pace_max_segs;
13674 		log.u_bbr.flex4 = orig_len;
13675 		if (filled_all)
13676 			log.u_bbr.flex5 = 0x80000000;
13677 		else
13678 			log.u_bbr.flex5 = 0;
13679 		/* Save off the early/late values */
13680 		log.u_bbr.flex6 = rack->r_ctl.rc_agg_early;
13681 		log.u_bbr.applimited = rack->r_ctl.rc_agg_delayed;
13682 		log.u_bbr.bw_inuse = rack_get_bw(rack);
13683 		if (rsm || sack_rxmit) {
13684 			if (doing_tlp)
13685 				log.u_bbr.flex8 = 2;
13686 			else
13687 				log.u_bbr.flex8 = 1;
13688 		} else {
13689 			log.u_bbr.flex8 = 0;
13690 		}
13691 		log.u_bbr.pacing_gain = rack_get_output_gain(rack, rsm);
13692 		log.u_bbr.flex7 = mark;
13693 		log.u_bbr.pkts_out = tp->t_maxseg;
13694 		log.u_bbr.timeStamp = tcp_get_usecs(&tv);
13695 		log.u_bbr.inflight = ctf_flight_size(rack->rc_tp, rack->r_ctl.rc_sacked);
13696 		log.u_bbr.lt_epoch = cwnd_to_use;
13697 		log.u_bbr.delivered = sendalot;
13698 		lgb = tcp_log_event_(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_OUT, ERRNO_UNK,
13699 				     len, &log, false, NULL, NULL, 0, &tv);
13700 	} else
13701 		lgb = NULL;
13702 
13703 	/*
13704 	 * Fill in IP length and desired time to live and send to IP level.
13705 	 * There should be a better way to handle ttl and tos; we could keep
13706 	 * them in the template, but need a way to checksum without them.
13707 	 */
13708 	/*
13709 	 * m->m_pkthdr.len should have been set before cksum calcuration,
13710 	 * because in6_cksum() need it.
13711 	 */
13712 #ifdef INET6
13713 	if (isipv6) {
13714 		/*
13715 		 * we separately set hoplimit for every segment, since the
13716 		 * user might want to change the value via setsockopt. Also,
13717 		 * desired default hop limit might be changed via Neighbor
13718 		 * Discovery.
13719 		 */
13720 		ip6->ip6_hlim = in6_selecthlim(inp, NULL);
13721 
13722 		/*
13723 		 * Set the packet size here for the benefit of DTrace
13724 		 * probes. ip6_output() will set it properly; it's supposed
13725 		 * to include the option header lengths as well.
13726 		 */
13727 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
13728 
13729 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss)
13730 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
13731 		else
13732 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
13733 
13734 		if (tp->t_state == TCPS_SYN_SENT)
13735 			TCP_PROBE5(connect__request, NULL, tp, ip6, tp, th);
13736 
13737 		TCP_PROBE5(send, NULL, tp, ip6, tp, th);
13738 		/* TODO: IPv6 IP6TOS_ECT bit on */
13739 		error = ip6_output(m, inp->in6p_outputopts,
13740 				   &inp->inp_route6,
13741 				   ((rsm || sack_rxmit) ? IP_NO_SND_TAG_RL : 0),
13742 				   NULL, NULL, inp);
13743 
13744 		if (error == EMSGSIZE && inp->inp_route6.ro_nh != NULL)
13745 			mtu = inp->inp_route6.ro_nh->nh_mtu;
13746 	}
13747 #endif				/* INET6 */
13748 #if defined(INET) && defined(INET6)
13749 	else
13750 #endif
13751 #ifdef INET
13752 	{
13753 		ip->ip_len = htons(m->m_pkthdr.len);
13754 #ifdef INET6
13755 		if (inp->inp_vflag & INP_IPV6PROTO)
13756 			ip->ip_ttl = in6_selecthlim(inp, NULL);
13757 #endif				/* INET6 */
13758 		/*
13759 		 * If we do path MTU discovery, then we set DF on every
13760 		 * packet. This might not be the best thing to do according
13761 		 * to RFC3390 Section 2. However the tcp hostcache migitates
13762 		 * the problem so it affects only the first tcp connection
13763 		 * with a host.
13764 		 *
13765 		 * NB: Don't set DF on small MTU/MSS to have a safe
13766 		 * fallback.
13767 		 */
13768 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) {
13769 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
13770 			if (tp->t_port == 0 || len < V_tcp_minmss) {
13771 				ip->ip_off |= htons(IP_DF);
13772 			}
13773 		} else {
13774 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
13775 		}
13776 
13777 		if (tp->t_state == TCPS_SYN_SENT)
13778 			TCP_PROBE5(connect__request, NULL, tp, ip, tp, th);
13779 
13780 		TCP_PROBE5(send, NULL, tp, ip, tp, th);
13781 
13782 		error = ip_output(m, inp->inp_options, &inp->inp_route,
13783 				  ((rsm || sack_rxmit) ? IP_NO_SND_TAG_RL : 0), 0,
13784 				  inp);
13785 		if (error == EMSGSIZE && inp->inp_route.ro_nh != NULL)
13786 			mtu = inp->inp_route.ro_nh->nh_mtu;
13787 	}
13788 #endif				/* INET */
13789 
13790 out:
13791 	if (lgb) {
13792 		lgb->tlb_errno = error;
13793 		lgb = NULL;
13794 	}
13795 	/*
13796 	 * In transmit state, time the transmission and arrange for the
13797 	 * retransmit.  In persist state, just set snd_max.
13798 	 */
13799 	if (error == 0) {
13800 		rack->forced_ack = 0;	/* If we send something zap the FA flag */
13801 		if (rsm && (doing_tlp == 0)) {
13802 			/* Set we retransmitted */
13803 			rack->rc_gp_saw_rec = 1;
13804 		} else {
13805 			if (cwnd_to_use > tp->snd_ssthresh) {
13806 				/* Set we sent in CA */
13807 				rack->rc_gp_saw_ca = 1;
13808 			} else {
13809 				/* Set we sent in SS */
13810 				rack->rc_gp_saw_ss = 1;
13811 			}
13812 		}
13813 		if (TCPS_HAVEESTABLISHED(tp->t_state) &&
13814 		    (tp->t_flags & TF_SACK_PERMIT) &&
13815 		    tp->rcv_numsacks > 0)
13816 			tcp_clean_dsack_blocks(tp);
13817 		tot_len_this_send += len;
13818 		if (len == 0)
13819 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_SNDACK], 1);
13820 		else if (len == 1) {
13821 			counter_u64_add(rack_out_size[TCP_MSS_ACCT_PERSIST], 1);
13822 		} else if (len > 1) {
13823 			int idx;
13824 
13825 			idx = (len / segsiz) + 3;
13826 			if (idx >= TCP_MSS_ACCT_ATIMER)
13827 				counter_u64_add(rack_out_size[(TCP_MSS_ACCT_ATIMER-1)], 1);
13828 			else
13829 				counter_u64_add(rack_out_size[idx], 1);
13830 		}
13831 	}
13832 	if (rack->rack_no_prr == 0) {
13833 		if (sub_from_prr && (error == 0)) {
13834 			if (rack->r_ctl.rc_prr_sndcnt >= len)
13835 				rack->r_ctl.rc_prr_sndcnt -= len;
13836 			else
13837 				rack->r_ctl.rc_prr_sndcnt = 0;
13838 		}
13839  	}
13840 	sub_from_prr = 0;
13841 	rack_log_output(tp, &to, len, rack_seq, (uint8_t) flags, error, cts,
13842 			pass, rsm, us_cts);
13843 	if ((error == 0) &&
13844 	    (len > 0) &&
13845 	    (tp->snd_una == tp->snd_max))
13846 		rack->r_ctl.rc_tlp_rxt_last_time = cts;
13847 	/* Now are we in persists? */
13848 	if (rack->rc_in_persist == 0) {
13849 		tcp_seq startseq = tp->snd_nxt;
13850 
13851 		/* Track our lost count */
13852 		if (rsm && (doing_tlp == 0))
13853 			rack->r_ctl.rc_loss_count += rsm->r_end - rsm->r_start;
13854 		/*
13855 		 * Advance snd_nxt over sequence space of this segment.
13856 		 */
13857 		if (error)
13858 			/* We don't log or do anything with errors */
13859 			goto nomore;
13860 		if (doing_tlp == 0) {
13861 			if (rsm == NULL) {
13862 				/*
13863 				 * Not a retransmission of some
13864 				 * sort, new data is going out so
13865 				 * clear our TLP count and flag.
13866 				 */
13867 				rack->rc_tlp_in_progress = 0;
13868 				rack->r_ctl.rc_tlp_cnt_out = 0;
13869 			}
13870 		} else {
13871 			/*
13872 			 * We have just sent a TLP, mark that it is true
13873 			 * and make sure our in progress is set so we
13874 			 * continue to check the count.
13875 			 */
13876 			rack->rc_tlp_in_progress = 1;
13877 			rack->r_ctl.rc_tlp_cnt_out++;
13878 		}
13879 		if (flags & (TH_SYN | TH_FIN)) {
13880 			if (flags & TH_SYN)
13881 				tp->snd_nxt++;
13882 			if (flags & TH_FIN) {
13883 				tp->snd_nxt++;
13884 				tp->t_flags |= TF_SENTFIN;
13885 			}
13886 		}
13887 		/* In the ENOBUFS case we do *not* update snd_max */
13888 		if (sack_rxmit)
13889 			goto nomore;
13890 
13891 		tp->snd_nxt += len;
13892 		if (SEQ_GT(tp->snd_nxt, tp->snd_max)) {
13893 			if (tp->snd_una == tp->snd_max) {
13894 				/*
13895 				 * Update the time we just added data since
13896 				 * none was outstanding.
13897 				 */
13898 				rack_log_progress_event(rack, tp, ticks, PROGRESS_START, __LINE__);
13899 				tp->t_acktime = ticks;
13900 			}
13901 			tp->snd_max = tp->snd_nxt;
13902 			/*
13903 			 * Time this transmission if not a retransmission and
13904 			 * not currently timing anything.
13905 			 * This is only relevant in case of switching back to
13906 			 * the base stack.
13907 			 */
13908 			if (tp->t_rtttime == 0) {
13909 				tp->t_rtttime = ticks;
13910 				tp->t_rtseq = startseq;
13911 				KMOD_TCPSTAT_INC(tcps_segstimed);
13912 			}
13913 			if (len &&
13914 			    ((tp->t_flags & TF_GPUTINPROG) == 0))
13915 				rack_start_gp_measurement(tp, rack, startseq, sb_offset);
13916 		}
13917 	} else {
13918 		/*
13919 		 * Persist case, update snd_max but since we are in persist
13920 		 * mode (no window) we do not update snd_nxt.
13921 		 */
13922 		int32_t xlen = len;
13923 
13924 		if (error)
13925 			goto nomore;
13926 
13927 		if (flags & TH_SYN)
13928 			++xlen;
13929 		if (flags & TH_FIN) {
13930 			++xlen;
13931 			tp->t_flags |= TF_SENTFIN;
13932 		}
13933 		/* In the ENOBUFS case we do *not* update snd_max */
13934 		if (SEQ_GT(tp->snd_nxt + xlen, tp->snd_max)) {
13935 			if (tp->snd_una == tp->snd_max) {
13936 				/*
13937 				 * Update the time we just added data since
13938 				 * none was outstanding.
13939 				 */
13940 				rack_log_progress_event(rack, tp, ticks, PROGRESS_START, __LINE__);
13941 				tp->t_acktime = ticks;
13942 			}
13943 			tp->snd_max = tp->snd_nxt + len;
13944 		}
13945 	}
13946 nomore:
13947 	if (error) {
13948 		rack->r_ctl.rc_agg_delayed = 0;
13949 		rack->r_early = 0;
13950 		rack->r_late = 0;
13951 		rack->r_ctl.rc_agg_early = 0;
13952 		SOCKBUF_UNLOCK_ASSERT(sb);	/* Check gotos. */
13953 		/*
13954 		 * Failures do not advance the seq counter above. For the
13955 		 * case of ENOBUFS we will fall out and retry in 1ms with
13956 		 * the hpts. Everything else will just have to retransmit
13957 		 * with the timer.
13958 		 *
13959 		 * In any case, we do not want to loop around for another
13960 		 * send without a good reason.
13961 		 */
13962 		sendalot = 0;
13963 		switch (error) {
13964 		case EPERM:
13965 			tp->t_softerror = error;
13966 			return (error);
13967 		case ENOBUFS:
13968 			if (slot == 0) {
13969 				/*
13970 				 * Pace us right away to retry in a some
13971 				 * time
13972 				 */
13973 				slot = ((1 + rack->rc_enobuf) * HPTS_USEC_IN_MSEC);
13974 				if (rack->rc_enobuf < 126)
13975 					rack->rc_enobuf++;
13976 				if (slot > ((rack->rc_rack_rtt / 2) * HPTS_USEC_IN_MSEC)) {
13977 					slot = (rack->rc_rack_rtt / 2) * HPTS_USEC_IN_MSEC;
13978 				}
13979 				if (slot < (10 * HPTS_USEC_IN_MSEC))
13980 					slot = 10 * HPTS_USEC_IN_MSEC;
13981 			}
13982 			counter_u64_add(rack_saw_enobuf, 1);
13983 			error = 0;
13984 			goto enobufs;
13985 		case EMSGSIZE:
13986 			/*
13987 			 * For some reason the interface we used initially
13988 			 * to send segments changed to another or lowered
13989 			 * its MTU. If TSO was active we either got an
13990 			 * interface without TSO capabilits or TSO was
13991 			 * turned off. If we obtained mtu from ip_output()
13992 			 * then update it and try again.
13993 			 */
13994 			if (tso)
13995 				tp->t_flags &= ~TF_TSO;
13996 			if (mtu != 0) {
13997 				tcp_mss_update(tp, -1, mtu, NULL, NULL);
13998 				goto again;
13999 			}
14000 			slot = 10 * HPTS_USEC_IN_MSEC;
14001 			rack_start_hpts_timer(rack, tp, cts, slot, 0, 0);
14002 			return (error);
14003 		case ENETUNREACH:
14004 			counter_u64_add(rack_saw_enetunreach, 1);
14005 		case EHOSTDOWN:
14006 		case EHOSTUNREACH:
14007 		case ENETDOWN:
14008 			if (TCPS_HAVERCVDSYN(tp->t_state)) {
14009 				tp->t_softerror = error;
14010 			}
14011 			/* FALLTHROUGH */
14012 		default:
14013 			slot = 10 * HPTS_USEC_IN_MSEC;
14014 			rack_start_hpts_timer(rack, tp, cts, slot, 0, 0);
14015 			return (error);
14016 		}
14017 	} else {
14018 		rack->rc_enobuf = 0;
14019 	}
14020 	KMOD_TCPSTAT_INC(tcps_sndtotal);
14021 
14022 	/*
14023 	 * Data sent (as far as we can tell). If this advertises a larger
14024 	 * window than any other segment, then remember the size of the
14025 	 * advertised window. Any pending ACK has now been sent.
14026 	 */
14027 	if (recwin > 0 && SEQ_GT(tp->rcv_nxt + recwin, tp->rcv_adv))
14028 		tp->rcv_adv = tp->rcv_nxt + recwin;
14029 	tp->last_ack_sent = tp->rcv_nxt;
14030 	tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
14031 enobufs:
14032 	/* Assure when we leave that snd_nxt will point to top */
14033 	if (SEQ_GT(tp->snd_max, tp->snd_nxt))
14034 		tp->snd_nxt = tp->snd_max;
14035 	if (sendalot) {
14036 		/* Do we need to turn off sendalot? */
14037 		if (rack->r_ctl.rc_pace_max_segs &&
14038 		    (tot_len_this_send >= rack->r_ctl.rc_pace_max_segs)) {
14039 			/* We hit our max. */
14040 			sendalot = 0;
14041 		} else if ((rack->rc_user_set_max_segs) &&
14042 			   (tot_len_this_send >= (rack->rc_user_set_max_segs * segsiz))) {
14043 			/* We hit the user defined max */
14044 			sendalot = 0;
14045 		}
14046 	}
14047 	if ((error == 0) && (flags & TH_FIN))
14048 		tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_FIN);
14049 	if (flags & TH_RST) {
14050 		/*
14051 		 * We don't send again after sending a RST.
14052 		 */
14053 		slot = 0;
14054 		sendalot = 0;
14055 		if (error == 0)
14056 			tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
14057 	} else if ((slot == 0) && (sendalot == 0) && tot_len_this_send) {
14058 		/*
14059 		 * Get our pacing rate, if an error
14060 		 * occured in sending (ENOBUF) we would
14061 		 * hit the else if with slot preset. Other
14062 		 * errors return.
14063 		 */
14064 		slot = rack_get_pacing_delay(rack, tp, tot_len_this_send, rsm, segsiz);
14065 	}
14066 	if (rsm &&
14067 	    rack->use_rack_rr) {
14068 		/* Its a retransmit and we use the rack cheat? */
14069 		if ((slot == 0) ||
14070 		    (rack->rc_always_pace == 0) ||
14071 		    (rack->r_rr_config == 1)) {
14072 			/*
14073 			 * We have no pacing set or we
14074 			 * are using old-style rack or
14075 			 * we are overriden to use the old 1ms pacing.
14076 			 */
14077 			slot = rack->r_ctl.rc_min_to * HPTS_USEC_IN_MSEC;
14078 		}
14079 	}
14080 	if (slot) {
14081 		/* set the rack tcb into the slot N */
14082 		counter_u64_add(rack_paced_segments, 1);
14083 	} else if (sendalot) {
14084 		if (len)
14085 			counter_u64_add(rack_unpaced_segments, 1);
14086 		sack_rxmit = 0;
14087 		goto again;
14088 	} else if (len) {
14089 		counter_u64_add(rack_unpaced_segments, 1);
14090 	}
14091 	rack_start_hpts_timer(rack, tp, cts, slot, tot_len_this_send, 0);
14092 	return (error);
14093 }
14094 
14095 static void
14096 rack_update_seg(struct tcp_rack *rack)
14097 {
14098 	uint32_t orig_val;
14099 
14100 	orig_val = rack->r_ctl.rc_pace_max_segs;
14101 	rack_set_pace_segments(rack->rc_tp, rack, __LINE__);
14102 	if (orig_val != rack->r_ctl.rc_pace_max_segs)
14103 		rack_log_pacing_delay_calc(rack, 0, 0, orig_val, 0, 0, 15, __LINE__, NULL);
14104 }
14105 
14106 /*
14107  * rack_ctloutput() must drop the inpcb lock before performing copyin on
14108  * socket option arguments.  When it re-acquires the lock after the copy, it
14109  * has to revalidate that the connection is still valid for the socket
14110  * option.
14111  */
14112 static int
14113 rack_set_sockopt(struct socket *so, struct sockopt *sopt,
14114     struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack)
14115 {
14116 	struct epoch_tracker et;
14117 	uint64_t val;
14118 	int32_t error = 0, optval;
14119 	uint16_t ca, ss;
14120 
14121 	switch (sopt->sopt_name) {
14122 	case TCP_RACK_PROP_RATE:		/*  URL:prop_rate */
14123 	case TCP_RACK_PROP	:		/*  URL:prop */
14124 	case TCP_RACK_TLP_REDUCE:		/*  URL:tlp_reduce */
14125 	case TCP_RACK_EARLY_RECOV:		/*  URL:early_recov */
14126 	case TCP_RACK_PACE_REDUCE:		/*  Not used */
14127         /*  Pacing related ones */
14128 	case TCP_RACK_PACE_ALWAYS:		/*  URL:pace_always */
14129 	case TCP_BBR_RACK_INIT_RATE:		/*  URL:irate */
14130 	case TCP_BBR_IWINTSO:			/*  URL:tso_iwin */
14131 	case TCP_RACK_PACE_MAX_SEG:		/*  URL:pace_max_seg */
14132 	case TCP_RACK_FORCE_MSEG:		/*  URL:force_max_seg */
14133 	case TCP_RACK_PACE_RATE_CA:		/*  URL:pr_ca */
14134 	case TCP_RACK_PACE_RATE_SS:		/*  URL:pr_ss*/
14135 	case TCP_RACK_PACE_RATE_REC:		/*  URL:pr_rec */
14136 	case TCP_RACK_GP_INCREASE_CA:		/*  URL:gp_inc_ca */
14137 	case TCP_RACK_GP_INCREASE_SS:		/*  URL:gp_inc_ss */
14138 	case TCP_RACK_GP_INCREASE_REC:		/*  URL:gp_inc_rec */
14139 	case TCP_RACK_RR_CONF:			/*  URL:rrr_conf */
14140 	case TCP_BBR_HDWR_PACE:			/*  URL:hdwrpace */
14141        /* End pacing related */
14142 	case TCP_DELACK:
14143 	case TCP_RACK_PRR_SENDALOT:		/*  URL:prr_sendalot */
14144 	case TCP_RACK_MIN_TO:			/*  URL:min_to */
14145 	case TCP_RACK_EARLY_SEG:		/*  URL:early_seg */
14146 	case TCP_RACK_REORD_THRESH:		/*  URL:reord_thresh */
14147 	case TCP_RACK_REORD_FADE:		/*  URL:reord_fade */
14148 	case TCP_RACK_TLP_THRESH:		/*  URL:tlp_thresh */
14149 	case TCP_RACK_PKT_DELAY:		/*  URL:pkt_delay */
14150 	case TCP_RACK_TLP_USE:			/*  URL:tlp_use */
14151 	case TCP_RACK_TLP_INC_VAR:		/*  URL:tlp_inc_var */
14152 	case TCP_RACK_IDLE_REDUCE_HIGH:		/*  URL:idle_reduce_high */
14153 	case TCP_BBR_RACK_RTT_USE:		/*  URL:rttuse */
14154 	case TCP_BBR_USE_RACK_RR:		/*  URL:rackrr */
14155 	case TCP_RACK_DO_DETECTION:		/*  URL:detect */
14156 	case TCP_NO_PRR:			/*  URL:noprr */
14157 	case TCP_TIMELY_DYN_ADJ:		/*  URL:dynamic */
14158 	case TCP_DATA_AFTER_CLOSE:
14159 	case TCP_RACK_NONRXT_CFG_RATE:		/*  URL:nonrxtcr */
14160 	case TCP_SHARED_CWND_ENABLE:		/*  URL:scwnd */
14161 	case TCP_RACK_MBUF_QUEUE:		/*  URL:mqueue */
14162 	case TCP_RACK_NO_PUSH_AT_MAX:		/*  URL:npush */
14163 	case TCP_RACK_PACE_TO_FILL:		/*  URL:fillcw */
14164 	case TCP_SHARED_CWND_TIME_LIMIT:	/*  URL:lscwnd */
14165 	case TCP_RACK_PROFILE:			/*  URL:profile */
14166 		break;
14167 	default:
14168 		return (tcp_default_ctloutput(so, sopt, inp, tp));
14169 		break;
14170 	}
14171 	INP_WUNLOCK(inp);
14172 	error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
14173 	if (error)
14174 		return (error);
14175 	INP_WLOCK(inp);
14176 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
14177 		INP_WUNLOCK(inp);
14178 		return (ECONNRESET);
14179 	}
14180 	tp = intotcpcb(inp);
14181 	rack = (struct tcp_rack *)tp->t_fb_ptr;
14182 	switch (sopt->sopt_name) {
14183 	case TCP_RACK_PROFILE:
14184 		RACK_OPTS_INC(tcp_profile);
14185 		if (optval == 1) {
14186 			/* pace_always=1 */
14187 			rack->rc_always_pace = 1;
14188 			tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
14189 			/* scwnd=1 */
14190 			rack->rack_enable_scwnd = 1;
14191 			/* dynamic=100 */
14192 			rack->rc_gp_dyn_mul = 1;
14193 			rack->r_ctl.rack_per_of_gp_ca = 100;
14194 			/* rrr_conf=3 */
14195 			rack->r_rr_config = 3;
14196 			/* npush=2 */
14197 			rack->r_ctl.rc_no_push_at_mrtt = 2;
14198 			/* fillcw=1 */
14199 			rack->rc_pace_to_cwnd = 1;
14200 			rack->rc_pace_fill_if_rttin_range = 0;
14201 			rack->rtt_limit_mul = 0;
14202 			/* noprr=1 */
14203 			rack->rack_no_prr = 1;
14204 			/* lscwnd=1 */
14205 			rack->r_limit_scw = 1;
14206 		} else if (optval == 2) {
14207 			/* pace_always=1 */
14208 			rack->rc_always_pace = 1;
14209 			tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
14210 			/* scwnd=1 */
14211 			rack->rack_enable_scwnd = 1;
14212 			/* dynamic=100 */
14213 			rack->rc_gp_dyn_mul = 1;
14214 			rack->r_ctl.rack_per_of_gp_ca = 100;
14215 			/* rrr_conf=3 */
14216 			rack->r_rr_config = 3;
14217 			/* npush=2 */
14218 			rack->r_ctl.rc_no_push_at_mrtt = 2;
14219 			/* fillcw=1 */
14220 			rack->rc_pace_to_cwnd = 1;
14221 			rack->rc_pace_fill_if_rttin_range = 0;
14222 			rack->rtt_limit_mul = 0;
14223 			/* noprr=1 */
14224 			rack->rack_no_prr = 1;
14225 			/* lscwnd=0 */
14226 			rack->r_limit_scw = 0;
14227 		}
14228 		break;
14229 	case TCP_SHARED_CWND_TIME_LIMIT:
14230 		RACK_OPTS_INC(tcp_lscwnd);
14231 		if (optval)
14232 			rack->r_limit_scw = 1;
14233 		else
14234 			rack->r_limit_scw = 0;
14235 		break;
14236  	case TCP_RACK_PACE_TO_FILL:
14237 		RACK_OPTS_INC(tcp_fillcw);
14238 		if (optval == 0)
14239 			rack->rc_pace_to_cwnd = 0;
14240 		else
14241 			rack->rc_pace_to_cwnd = 1;
14242 		if ((optval >= rack_gp_rtt_maxmul) &&
14243 		    rack_gp_rtt_maxmul &&
14244 		    (optval < 0xf)) {
14245 			rack->rc_pace_fill_if_rttin_range = 1;
14246 			rack->rtt_limit_mul = optval;
14247 		} else {
14248 			rack->rc_pace_fill_if_rttin_range = 0;
14249 			rack->rtt_limit_mul = 0;
14250 		}
14251 		break;
14252 	case TCP_RACK_NO_PUSH_AT_MAX:
14253 		RACK_OPTS_INC(tcp_npush);
14254 		if (optval == 0)
14255 			rack->r_ctl.rc_no_push_at_mrtt = 0;
14256 		else if (optval < 0xff)
14257 			rack->r_ctl.rc_no_push_at_mrtt = optval;
14258 		else
14259 			error = EINVAL;
14260 		break;
14261 	case TCP_SHARED_CWND_ENABLE:
14262 		RACK_OPTS_INC(tcp_rack_scwnd);
14263 		if (optval == 0)
14264 			rack->rack_enable_scwnd = 0;
14265 		else
14266 			rack->rack_enable_scwnd = 1;
14267 		break;
14268 	case TCP_RACK_MBUF_QUEUE:
14269 		/* Now do we use the LRO mbuf-queue feature */
14270 		RACK_OPTS_INC(tcp_rack_mbufq);
14271 		if (optval)
14272 			rack->r_mbuf_queue = 1;
14273 		else
14274 			rack->r_mbuf_queue = 0;
14275 		if  (rack->r_mbuf_queue || rack->rc_always_pace)
14276 			tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
14277 		else
14278 			tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
14279 		break;
14280 	case TCP_RACK_NONRXT_CFG_RATE:
14281 		RACK_OPTS_INC(tcp_rack_cfg_rate);
14282 		if (optval == 0)
14283 			rack->rack_rec_nonrxt_use_cr = 0;
14284 		else
14285 			rack->rack_rec_nonrxt_use_cr = 1;
14286 		break;
14287 	case TCP_NO_PRR:
14288 		RACK_OPTS_INC(tcp_rack_noprr);
14289 		if (optval == 0)
14290 			rack->rack_no_prr = 0;
14291 		else
14292 			rack->rack_no_prr = 1;
14293 		break;
14294 	case TCP_TIMELY_DYN_ADJ:
14295 		RACK_OPTS_INC(tcp_timely_dyn);
14296 		if (optval == 0)
14297 			rack->rc_gp_dyn_mul = 0;
14298 		else {
14299 			rack->rc_gp_dyn_mul = 1;
14300 			if (optval >= 100) {
14301 				/*
14302 				 * If the user sets something 100 or more
14303 				 * its the gp_ca value.
14304 				 */
14305 				rack->r_ctl.rack_per_of_gp_ca  = optval;
14306 			}
14307 		}
14308 		break;
14309 	case TCP_RACK_DO_DETECTION:
14310 		RACK_OPTS_INC(tcp_rack_do_detection);
14311 		if (optval == 0)
14312 			rack->do_detection = 0;
14313 		else
14314 			rack->do_detection = 1;
14315 		break;
14316 	case TCP_RACK_PROP_RATE:
14317 		if ((optval <= 0) || (optval >= 100)) {
14318 			error = EINVAL;
14319 			break;
14320 		}
14321 		RACK_OPTS_INC(tcp_rack_prop_rate);
14322 		rack->r_ctl.rc_prop_rate = optval;
14323 		break;
14324 	case TCP_RACK_TLP_USE:
14325 		if ((optval < TLP_USE_ID) || (optval > TLP_USE_TWO_TWO)) {
14326 			error = EINVAL;
14327 			break;
14328 		}
14329 		RACK_OPTS_INC(tcp_tlp_use);
14330 		rack->rack_tlp_threshold_use = optval;
14331 		break;
14332 	case TCP_RACK_PROP:
14333 		/* RACK proportional rate reduction (bool) */
14334 		RACK_OPTS_INC(tcp_rack_prop);
14335 		rack->r_ctl.rc_prop_reduce = optval;
14336 		break;
14337 	case TCP_RACK_TLP_REDUCE:
14338 		/* RACK TLP cwnd reduction (bool) */
14339 		RACK_OPTS_INC(tcp_rack_tlp_reduce);
14340 		rack->r_ctl.rc_tlp_cwnd_reduce = optval;
14341 		break;
14342 	case TCP_RACK_EARLY_RECOV:
14343 		/* Should recovery happen early (bool) */
14344 		RACK_OPTS_INC(tcp_rack_early_recov);
14345 		rack->r_ctl.rc_early_recovery = optval;
14346 		break;
14347 
14348         /*  Pacing related ones */
14349 	case TCP_RACK_PACE_ALWAYS:
14350 		/*
14351 		 * zero is old rack method, 1 is new
14352 		 * method using a pacing rate.
14353 		 */
14354 		RACK_OPTS_INC(tcp_rack_pace_always);
14355 		if (optval > 0)
14356 			rack->rc_always_pace = 1;
14357 		else
14358 			rack->rc_always_pace = 0;
14359 		if  (rack->r_mbuf_queue || rack->rc_always_pace)
14360 			tp->t_inpcb->inp_flags2 |= INP_SUPPORTS_MBUFQ;
14361 		else
14362 			tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
14363 		/* A rate may be set irate or other, if so set seg size */
14364 		rack_update_seg(rack);
14365 		break;
14366 	case TCP_BBR_RACK_INIT_RATE:
14367 		RACK_OPTS_INC(tcp_initial_rate);
14368 		val = optval;
14369 		/* Change from kbits per second to bytes per second */
14370 		val *= 1000;
14371 		val /= 8;
14372 		rack->r_ctl.init_rate = val;
14373 		if (rack->rc_init_win != rack_default_init_window) {
14374 			uint32_t win, snt;
14375 
14376 			/*
14377 			 * Options don't always get applied
14378 			 * in the order you think. So in order
14379 			 * to assure we update a cwnd we need
14380 			 * to check and see if we are still
14381 			 * where we should raise the cwnd.
14382 			 */
14383 			win = rc_init_window(rack);
14384 			if (SEQ_GT(tp->snd_max, tp->iss))
14385 				snt = tp->snd_max - tp->iss;
14386 			else
14387 				snt = 0;
14388 			if ((snt < win) &&
14389 			    (tp->snd_cwnd < win))
14390 				tp->snd_cwnd = win;
14391 		}
14392 		if (rack->rc_always_pace)
14393 			rack_update_seg(rack);
14394 		break;
14395 	case TCP_BBR_IWINTSO:
14396 		RACK_OPTS_INC(tcp_initial_win);
14397 		if (optval && (optval <= 0xff)) {
14398 			uint32_t win, snt;
14399 
14400 			rack->rc_init_win = optval;
14401 			win = rc_init_window(rack);
14402 			if (SEQ_GT(tp->snd_max, tp->iss))
14403 				snt = tp->snd_max - tp->iss;
14404 			else
14405 				snt = 0;
14406 			if ((snt < win) &&
14407 			    (tp->t_srtt |
14408 #ifdef NETFLIX_PEAKRATE
14409 			     tp->t_maxpeakrate |
14410 #endif
14411 			     rack->r_ctl.init_rate)) {
14412 				/*
14413 				 * We are not past the initial window
14414 				 * and we have some bases for pacing,
14415 				 * so we need to possibly adjust up
14416 				 * the cwnd. Note even if we don't set
14417 				 * the cwnd, its still ok to raise the rc_init_win
14418 				 * which can be used coming out of idle when we
14419 				 * would have a rate.
14420 				 */
14421 				if (tp->snd_cwnd < win)
14422 					tp->snd_cwnd = win;
14423 			}
14424 			if (rack->rc_always_pace)
14425 				rack_update_seg(rack);
14426 		} else
14427 			error = EINVAL;
14428 		break;
14429 	case TCP_RACK_FORCE_MSEG:
14430 		RACK_OPTS_INC(tcp_rack_force_max_seg);
14431 		if (optval)
14432 			rack->rc_force_max_seg = 1;
14433 		else
14434 			rack->rc_force_max_seg = 0;
14435 		break;
14436 	case TCP_RACK_PACE_MAX_SEG:
14437 		/* Max segments size in a pace in bytes */
14438 		RACK_OPTS_INC(tcp_rack_max_seg);
14439 		rack->rc_user_set_max_segs = optval;
14440 		rack_set_pace_segments(tp, rack, __LINE__);
14441 		break;
14442 	case TCP_RACK_PACE_RATE_REC:
14443 		/* Set the fixed pacing rate in Bytes per second ca */
14444 		RACK_OPTS_INC(tcp_rack_pace_rate_rec);
14445 		rack->r_ctl.rc_fixed_pacing_rate_rec = optval;
14446 		if (rack->r_ctl.rc_fixed_pacing_rate_ca == 0)
14447 			rack->r_ctl.rc_fixed_pacing_rate_ca = optval;
14448 		if (rack->r_ctl.rc_fixed_pacing_rate_ss == 0)
14449 			rack->r_ctl.rc_fixed_pacing_rate_ss = optval;
14450 		rack->use_fixed_rate = 1;
14451 		rack_log_pacing_delay_calc(rack,
14452 					   rack->r_ctl.rc_fixed_pacing_rate_ss,
14453 					   rack->r_ctl.rc_fixed_pacing_rate_ca,
14454 					   rack->r_ctl.rc_fixed_pacing_rate_rec, 0, 0, 8,
14455 					   __LINE__, NULL);
14456 		break;
14457 
14458 	case TCP_RACK_PACE_RATE_SS:
14459 		/* Set the fixed pacing rate in Bytes per second ca */
14460 		RACK_OPTS_INC(tcp_rack_pace_rate_ss);
14461 		rack->r_ctl.rc_fixed_pacing_rate_ss = optval;
14462 		if (rack->r_ctl.rc_fixed_pacing_rate_ca == 0)
14463 			rack->r_ctl.rc_fixed_pacing_rate_ca = optval;
14464 		if (rack->r_ctl.rc_fixed_pacing_rate_rec == 0)
14465 			rack->r_ctl.rc_fixed_pacing_rate_rec = optval;
14466 		rack->use_fixed_rate = 1;
14467 		rack_log_pacing_delay_calc(rack,
14468 					   rack->r_ctl.rc_fixed_pacing_rate_ss,
14469 					   rack->r_ctl.rc_fixed_pacing_rate_ca,
14470 					   rack->r_ctl.rc_fixed_pacing_rate_rec, 0, 0, 8,
14471 					   __LINE__, NULL);
14472 		break;
14473 
14474 	case TCP_RACK_PACE_RATE_CA:
14475 		/* Set the fixed pacing rate in Bytes per second ca */
14476 		RACK_OPTS_INC(tcp_rack_pace_rate_ca);
14477 		rack->r_ctl.rc_fixed_pacing_rate_ca = optval;
14478 		if (rack->r_ctl.rc_fixed_pacing_rate_ss == 0)
14479 			rack->r_ctl.rc_fixed_pacing_rate_ss = optval;
14480 		if (rack->r_ctl.rc_fixed_pacing_rate_rec == 0)
14481 			rack->r_ctl.rc_fixed_pacing_rate_rec = optval;
14482 		rack->use_fixed_rate = 1;
14483 		rack_log_pacing_delay_calc(rack,
14484 					   rack->r_ctl.rc_fixed_pacing_rate_ss,
14485 					   rack->r_ctl.rc_fixed_pacing_rate_ca,
14486 					   rack->r_ctl.rc_fixed_pacing_rate_rec, 0, 0, 8,
14487 					   __LINE__, NULL);
14488 		break;
14489 	case TCP_RACK_GP_INCREASE_REC:
14490 		RACK_OPTS_INC(tcp_gp_inc_rec);
14491 		rack->r_ctl.rack_per_of_gp_rec = optval;
14492 		rack_log_pacing_delay_calc(rack,
14493 					   rack->r_ctl.rack_per_of_gp_ss,
14494 					   rack->r_ctl.rack_per_of_gp_ca,
14495 					   rack->r_ctl.rack_per_of_gp_rec, 0, 0, 1,
14496 					   __LINE__, NULL);
14497 		break;
14498 	case TCP_RACK_GP_INCREASE_CA:
14499 		RACK_OPTS_INC(tcp_gp_inc_ca);
14500 		ca = optval;
14501 		if (ca < 100) {
14502 			/*
14503 			 * We don't allow any reduction
14504 			 * over the GP b/w.
14505 			 */
14506 			error = EINVAL;
14507 			break;
14508 		}
14509 		rack->r_ctl.rack_per_of_gp_ca = ca;
14510 		rack_log_pacing_delay_calc(rack,
14511 					   rack->r_ctl.rack_per_of_gp_ss,
14512 					   rack->r_ctl.rack_per_of_gp_ca,
14513 					   rack->r_ctl.rack_per_of_gp_rec, 0, 0, 1,
14514 					   __LINE__, NULL);
14515 		break;
14516 	case TCP_RACK_GP_INCREASE_SS:
14517 		RACK_OPTS_INC(tcp_gp_inc_ss);
14518 		ss = optval;
14519 		if (ss < 100) {
14520 			/*
14521 			 * We don't allow any reduction
14522 			 * over the GP b/w.
14523 			 */
14524 			error = EINVAL;
14525 			break;
14526 		}
14527 		rack->r_ctl.rack_per_of_gp_ss = ss;
14528 		rack_log_pacing_delay_calc(rack,
14529 					   rack->r_ctl.rack_per_of_gp_ss,
14530 					   rack->r_ctl.rack_per_of_gp_ca,
14531 					   rack->r_ctl.rack_per_of_gp_rec, 0, 0, 1,
14532 					   __LINE__, NULL);
14533 		break;
14534 	case TCP_RACK_RR_CONF:
14535 		RACK_OPTS_INC(tcp_rack_rrr_no_conf_rate);
14536 		if (optval && optval <= 3)
14537 			rack->r_rr_config = optval;
14538 		else
14539 			rack->r_rr_config = 0;
14540 		break;
14541 	case TCP_BBR_HDWR_PACE:
14542 		RACK_OPTS_INC(tcp_hdwr_pacing);
14543 		if (optval){
14544 			if (rack->rack_hdrw_pacing == 0) {
14545 				rack->rack_hdw_pace_ena = 1;
14546 				rack->rack_attempt_hdwr_pace = 0;
14547 			} else
14548 				error = EALREADY;
14549 		} else {
14550 			rack->rack_hdw_pace_ena = 0;
14551 #ifdef RATELIMIT
14552 			if (rack->rack_hdrw_pacing) {
14553 				rack->rack_hdrw_pacing = 0;
14554 				in_pcbdetach_txrtlmt(rack->rc_inp);
14555 			}
14556 #endif
14557 		}
14558 		break;
14559         /*  End Pacing related ones */
14560 	case TCP_RACK_PRR_SENDALOT:
14561 		/* Allow PRR to send more than one seg */
14562 		RACK_OPTS_INC(tcp_rack_prr_sendalot);
14563 		rack->r_ctl.rc_prr_sendalot = optval;
14564 		break;
14565 	case TCP_RACK_MIN_TO:
14566 		/* Minimum time between rack t-o's in ms */
14567 		RACK_OPTS_INC(tcp_rack_min_to);
14568 		rack->r_ctl.rc_min_to = optval;
14569 		break;
14570 	case TCP_RACK_EARLY_SEG:
14571 		/* If early recovery max segments */
14572 		RACK_OPTS_INC(tcp_rack_early_seg);
14573 		rack->r_ctl.rc_early_recovery_segs = optval;
14574 		break;
14575 	case TCP_RACK_REORD_THRESH:
14576 		/* RACK reorder threshold (shift amount) */
14577 		RACK_OPTS_INC(tcp_rack_reord_thresh);
14578 		if ((optval > 0) && (optval < 31))
14579 			rack->r_ctl.rc_reorder_shift = optval;
14580 		else
14581 			error = EINVAL;
14582 		break;
14583 	case TCP_RACK_REORD_FADE:
14584 		/* Does reordering fade after ms time */
14585 		RACK_OPTS_INC(tcp_rack_reord_fade);
14586 		rack->r_ctl.rc_reorder_fade = optval;
14587 		break;
14588 	case TCP_RACK_TLP_THRESH:
14589 		/* RACK TLP theshold i.e. srtt+(srtt/N) */
14590 		RACK_OPTS_INC(tcp_rack_tlp_thresh);
14591 		if (optval)
14592 			rack->r_ctl.rc_tlp_threshold = optval;
14593 		else
14594 			error = EINVAL;
14595 		break;
14596 	case TCP_BBR_USE_RACK_RR:
14597 		RACK_OPTS_INC(tcp_rack_rr);
14598 		if (optval)
14599 			rack->use_rack_rr = 1;
14600 		else
14601 			rack->use_rack_rr = 0;
14602 		break;
14603 	case TCP_RACK_PKT_DELAY:
14604 		/* RACK added ms i.e. rack-rtt + reord + N */
14605 		RACK_OPTS_INC(tcp_rack_pkt_delay);
14606 		rack->r_ctl.rc_pkt_delay = optval;
14607 		break;
14608 	case TCP_RACK_TLP_INC_VAR:
14609 		/* Does TLP include rtt variance in t-o */
14610 		error = EINVAL;
14611 		break;
14612 	case TCP_RACK_IDLE_REDUCE_HIGH:
14613 		error = EINVAL;
14614 		break;
14615 	case TCP_DELACK:
14616 		if (optval == 0)
14617 			tp->t_delayed_ack = 0;
14618 		else
14619 			tp->t_delayed_ack = 1;
14620 		if (tp->t_flags & TF_DELACK) {
14621 			tp->t_flags &= ~TF_DELACK;
14622 			tp->t_flags |= TF_ACKNOW;
14623 			NET_EPOCH_ENTER(et);
14624 			rack_output(tp);
14625 			NET_EPOCH_EXIT(et);
14626 		}
14627 		break;
14628 
14629 	case TCP_BBR_RACK_RTT_USE:
14630 		if ((optval != USE_RTT_HIGH) &&
14631 		    (optval != USE_RTT_LOW) &&
14632 		    (optval != USE_RTT_AVG))
14633 			error = EINVAL;
14634 		else
14635 			rack->r_ctl.rc_rate_sample_method = optval;
14636 		break;
14637 	case TCP_DATA_AFTER_CLOSE:
14638 		if (optval)
14639 			rack->rc_allow_data_af_clo = 1;
14640 		else
14641 			rack->rc_allow_data_af_clo = 0;
14642 		break;
14643 	case TCP_RACK_PACE_REDUCE:
14644 		/* sysctl only now */
14645 		error = EINVAL;
14646 		break;
14647 	default:
14648 		return (tcp_default_ctloutput(so, sopt, inp, tp));
14649 		break;
14650 	}
14651 #ifdef NETFLIX_STATS
14652 	tcp_log_socket_option(tp, sopt->sopt_name, optval, error);
14653 #endif
14654 	INP_WUNLOCK(inp);
14655 	return (error);
14656 }
14657 
14658 static int
14659 rack_get_sockopt(struct socket *so, struct sockopt *sopt,
14660     struct inpcb *inp, struct tcpcb *tp, struct tcp_rack *rack)
14661 {
14662 	int32_t error, optval;
14663 	uint64_t val;
14664 	/*
14665 	 * Because all our options are either boolean or an int, we can just
14666 	 * pull everything into optval and then unlock and copy. If we ever
14667 	 * add a option that is not a int, then this will have quite an
14668 	 * impact to this routine.
14669 	 */
14670 	error = 0;
14671 	switch (sopt->sopt_name) {
14672 	case TCP_RACK_PROFILE:
14673 		/* You cannot retrieve a profile, its write only */
14674 		error = EINVAL;
14675 		break;
14676 	case TCP_RACK_PACE_TO_FILL:
14677 		optval = rack->rc_pace_to_cwnd;
14678 		break;
14679 	case TCP_RACK_NO_PUSH_AT_MAX:
14680 		optval = rack->r_ctl.rc_no_push_at_mrtt;
14681 		break;
14682 	case TCP_SHARED_CWND_ENABLE:
14683 		optval = rack->rack_enable_scwnd;
14684 		break;
14685 	case TCP_RACK_NONRXT_CFG_RATE:
14686 		optval = rack->rack_rec_nonrxt_use_cr;
14687 		break;
14688 	case TCP_NO_PRR:
14689 		optval = rack->rack_no_prr;
14690 		break;
14691 	case TCP_RACK_DO_DETECTION:
14692 		optval = rack->do_detection;
14693 		break;
14694 	case TCP_RACK_MBUF_QUEUE:
14695 		/* Now do we use the LRO mbuf-queue feature */
14696 		optval = rack->r_mbuf_queue;
14697 		break;
14698 	case TCP_TIMELY_DYN_ADJ:
14699 		optval = rack->rc_gp_dyn_mul;
14700 		break;
14701 	case TCP_BBR_IWINTSO:
14702 		optval = rack->rc_init_win;
14703 		break;
14704 	case TCP_RACK_PROP_RATE:
14705 		optval = rack->r_ctl.rc_prop_rate;
14706 		break;
14707 	case TCP_RACK_PROP:
14708 		/* RACK proportional rate reduction (bool) */
14709 		optval = rack->r_ctl.rc_prop_reduce;
14710 		break;
14711 	case TCP_RACK_TLP_REDUCE:
14712 		/* RACK TLP cwnd reduction (bool) */
14713 		optval = rack->r_ctl.rc_tlp_cwnd_reduce;
14714 		break;
14715 	case TCP_RACK_EARLY_RECOV:
14716 		/* Should recovery happen early (bool) */
14717 		optval = rack->r_ctl.rc_early_recovery;
14718 		break;
14719 	case TCP_RACK_PACE_REDUCE:
14720 		/* RACK Hptsi reduction factor (divisor) */
14721 		error = EINVAL;
14722 		break;
14723 	case TCP_BBR_RACK_INIT_RATE:
14724 		val = rack->r_ctl.init_rate;
14725 		/* convert to kbits per sec */
14726 		val *= 8;
14727 		val /= 1000;
14728 		optval = (uint32_t)val;
14729 		break;
14730 	case TCP_RACK_FORCE_MSEG:
14731 		optval = rack->rc_force_max_seg;
14732 		break;
14733 	case TCP_RACK_PACE_MAX_SEG:
14734 		/* Max segments in a pace */
14735 		optval = rack->rc_user_set_max_segs;
14736 		break;
14737 	case TCP_RACK_PACE_ALWAYS:
14738 		/* Use the always pace method */
14739 		optval = rack->rc_always_pace;
14740 		break;
14741 	case TCP_RACK_PRR_SENDALOT:
14742 		/* Allow PRR to send more than one seg */
14743 		optval = rack->r_ctl.rc_prr_sendalot;
14744 		break;
14745 	case TCP_RACK_MIN_TO:
14746 		/* Minimum time between rack t-o's in ms */
14747 		optval = rack->r_ctl.rc_min_to;
14748 		break;
14749 	case TCP_RACK_EARLY_SEG:
14750 		/* If early recovery max segments */
14751 		optval = rack->r_ctl.rc_early_recovery_segs;
14752 		break;
14753 	case TCP_RACK_REORD_THRESH:
14754 		/* RACK reorder threshold (shift amount) */
14755 		optval = rack->r_ctl.rc_reorder_shift;
14756 		break;
14757 	case TCP_RACK_REORD_FADE:
14758 		/* Does reordering fade after ms time */
14759 		optval = rack->r_ctl.rc_reorder_fade;
14760 		break;
14761 	case TCP_BBR_USE_RACK_RR:
14762 		/* Do we use the rack cheat for rxt */
14763 		optval = rack->use_rack_rr;
14764 		break;
14765 	case TCP_RACK_RR_CONF:
14766 		optval = rack->r_rr_config;
14767 		break;
14768 	case TCP_BBR_HDWR_PACE:
14769 		optval = rack->rack_hdw_pace_ena;
14770 		break;
14771 	case TCP_RACK_TLP_THRESH:
14772 		/* RACK TLP theshold i.e. srtt+(srtt/N) */
14773 		optval = rack->r_ctl.rc_tlp_threshold;
14774 		break;
14775 	case TCP_RACK_PKT_DELAY:
14776 		/* RACK added ms i.e. rack-rtt + reord + N */
14777 		optval = rack->r_ctl.rc_pkt_delay;
14778 		break;
14779 	case TCP_RACK_TLP_USE:
14780 		optval = rack->rack_tlp_threshold_use;
14781 		break;
14782 	case TCP_RACK_TLP_INC_VAR:
14783 		/* Does TLP include rtt variance in t-o */
14784 		error = EINVAL;
14785 		break;
14786 	case TCP_RACK_IDLE_REDUCE_HIGH:
14787 		error = EINVAL;
14788 		break;
14789 	case TCP_RACK_PACE_RATE_CA:
14790 		optval = rack->r_ctl.rc_fixed_pacing_rate_ca;
14791 		break;
14792 	case TCP_RACK_PACE_RATE_SS:
14793 		optval = rack->r_ctl.rc_fixed_pacing_rate_ss;
14794 		break;
14795 	case TCP_RACK_PACE_RATE_REC:
14796 		optval = rack->r_ctl.rc_fixed_pacing_rate_rec;
14797 		break;
14798 	case TCP_RACK_GP_INCREASE_SS:
14799 		optval = rack->r_ctl.rack_per_of_gp_ca;
14800 		break;
14801 	case TCP_RACK_GP_INCREASE_CA:
14802 		optval = rack->r_ctl.rack_per_of_gp_ss;
14803 		break;
14804 	case TCP_BBR_RACK_RTT_USE:
14805 		optval = rack->r_ctl.rc_rate_sample_method;
14806 		break;
14807 	case TCP_DELACK:
14808 		optval = tp->t_delayed_ack;
14809 		break;
14810 	case TCP_DATA_AFTER_CLOSE:
14811 		optval = rack->rc_allow_data_af_clo;
14812 		break;
14813 	case TCP_SHARED_CWND_TIME_LIMIT:
14814 		optval = rack->r_limit_scw;
14815 		break;
14816 	default:
14817 		return (tcp_default_ctloutput(so, sopt, inp, tp));
14818 		break;
14819 	}
14820 	INP_WUNLOCK(inp);
14821 	if (error == 0) {
14822 		error = sooptcopyout(sopt, &optval, sizeof optval);
14823 	}
14824 	return (error);
14825 }
14826 
14827 static int
14828 rack_ctloutput(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp)
14829 {
14830 	int32_t error = EINVAL;
14831 	struct tcp_rack *rack;
14832 
14833 	rack = (struct tcp_rack *)tp->t_fb_ptr;
14834 	if (rack == NULL) {
14835 		/* Huh? */
14836 		goto out;
14837 	}
14838 	if (sopt->sopt_dir == SOPT_SET) {
14839 		return (rack_set_sockopt(so, sopt, inp, tp, rack));
14840 	} else if (sopt->sopt_dir == SOPT_GET) {
14841 		return (rack_get_sockopt(so, sopt, inp, tp, rack));
14842 	}
14843 out:
14844 	INP_WUNLOCK(inp);
14845 	return (error);
14846 }
14847 
14848 static int
14849 rack_pru_options(struct tcpcb *tp, int flags)
14850 {
14851 	if (flags & PRUS_OOB)
14852 		return (EOPNOTSUPP);
14853 	return (0);
14854 }
14855 
14856 static struct tcp_function_block __tcp_rack = {
14857 	.tfb_tcp_block_name = __XSTRING(STACKNAME),
14858 	.tfb_tcp_output = rack_output,
14859 	.tfb_do_queued_segments = ctf_do_queued_segments,
14860 	.tfb_do_segment_nounlock = rack_do_segment_nounlock,
14861 	.tfb_tcp_do_segment = rack_do_segment,
14862 	.tfb_tcp_ctloutput = rack_ctloutput,
14863 	.tfb_tcp_fb_init = rack_init,
14864 	.tfb_tcp_fb_fini = rack_fini,
14865 	.tfb_tcp_timer_stop_all = rack_stopall,
14866 	.tfb_tcp_timer_activate = rack_timer_activate,
14867 	.tfb_tcp_timer_active = rack_timer_active,
14868 	.tfb_tcp_timer_stop = rack_timer_stop,
14869 	.tfb_tcp_rexmit_tmr = rack_remxt_tmr,
14870 	.tfb_tcp_handoff_ok = rack_handoff_ok,
14871 	.tfb_pru_options = rack_pru_options,
14872 };
14873 
14874 static const char *rack_stack_names[] = {
14875 	__XSTRING(STACKNAME),
14876 #ifdef STACKALIAS
14877 	__XSTRING(STACKALIAS),
14878 #endif
14879 };
14880 
14881 static int
14882 rack_ctor(void *mem, int32_t size, void *arg, int32_t how)
14883 {
14884 	memset(mem, 0, size);
14885 	return (0);
14886 }
14887 
14888 static void
14889 rack_dtor(void *mem, int32_t size, void *arg)
14890 {
14891 
14892 }
14893 
14894 static bool rack_mod_inited = false;
14895 
14896 static int
14897 tcp_addrack(module_t mod, int32_t type, void *data)
14898 {
14899 	int32_t err = 0;
14900 	int num_stacks;
14901 
14902 	switch (type) {
14903 	case MOD_LOAD:
14904 		rack_zone = uma_zcreate(__XSTRING(MODNAME) "_map",
14905 		    sizeof(struct rack_sendmap),
14906 		    rack_ctor, rack_dtor, NULL, NULL, UMA_ALIGN_PTR, 0);
14907 
14908 		rack_pcb_zone = uma_zcreate(__XSTRING(MODNAME) "_pcb",
14909 		    sizeof(struct tcp_rack),
14910 		    rack_ctor, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
14911 
14912 		sysctl_ctx_init(&rack_sysctl_ctx);
14913 		rack_sysctl_root = SYSCTL_ADD_NODE(&rack_sysctl_ctx,
14914 		    SYSCTL_STATIC_CHILDREN(_net_inet_tcp),
14915 		    OID_AUTO,
14916 #ifdef STACKALIAS
14917 		    __XSTRING(STACKALIAS),
14918 #else
14919 		    __XSTRING(STACKNAME),
14920 #endif
14921 		    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
14922 		    "");
14923 		if (rack_sysctl_root == NULL) {
14924 			printf("Failed to add sysctl node\n");
14925 			err = EFAULT;
14926 			goto free_uma;
14927 		}
14928 		rack_init_sysctls();
14929 		num_stacks = nitems(rack_stack_names);
14930 		err = register_tcp_functions_as_names(&__tcp_rack, M_WAITOK,
14931 		    rack_stack_names, &num_stacks);
14932 		if (err) {
14933 			printf("Failed to register %s stack name for "
14934 			    "%s module\n", rack_stack_names[num_stacks],
14935 			    __XSTRING(MODNAME));
14936 			sysctl_ctx_free(&rack_sysctl_ctx);
14937 free_uma:
14938 			uma_zdestroy(rack_zone);
14939 			uma_zdestroy(rack_pcb_zone);
14940 			rack_counter_destroy();
14941 			printf("Failed to register rack module -- err:%d\n", err);
14942 			return (err);
14943 		}
14944 		tcp_lro_reg_mbufq();
14945 		rack_mod_inited = true;
14946 		break;
14947 	case MOD_QUIESCE:
14948 		err = deregister_tcp_functions(&__tcp_rack, true, false);
14949 		break;
14950 	case MOD_UNLOAD:
14951 		err = deregister_tcp_functions(&__tcp_rack, false, true);
14952 		if (err == EBUSY)
14953 			break;
14954 		if (rack_mod_inited) {
14955 			uma_zdestroy(rack_zone);
14956 			uma_zdestroy(rack_pcb_zone);
14957 			sysctl_ctx_free(&rack_sysctl_ctx);
14958 			rack_counter_destroy();
14959 			rack_mod_inited = false;
14960 		}
14961 		tcp_lro_dereg_mbufq();
14962 		err = 0;
14963 		break;
14964 	default:
14965 		return (EOPNOTSUPP);
14966 	}
14967 	return (err);
14968 }
14969 
14970 static moduledata_t tcp_rack = {
14971 	.name = __XSTRING(MODNAME),
14972 	.evhand = tcp_addrack,
14973 	.priv = 0
14974 };
14975 
14976 MODULE_VERSION(MODNAME, 1);
14977 DECLARE_MODULE(MODNAME, tcp_rack, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
14978 MODULE_DEPEND(MODNAME, tcphpts, 1, 1, 1);
14979