xref: /freebsd/sys/netinet/tcp_stacks/bbr.c (revision 6f63e88c0166ed3e5f2805a9e667c7d24d304cf1) 
1 /*-
2  * Copyright (c) 2016-9
3  *	Netflix Inc.
4  *      All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  */
28 /**
29  * Author: Randall Stewart <rrs@netflix.com>
30  * This work is based on the ACM Queue paper
31  * BBR - Congestion Based Congestion Control
32  * and also numerous discussions with Neal, Yuchung and Van.
33  */
34 
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include "opt_inet.h"
39 #include "opt_inet6.h"
40 #include "opt_ipsec.h"
41 #include "opt_tcpdebug.h"
42 #include "opt_ratelimit.h"
43 #include "opt_kern_tls.h"
44 #include <sys/param.h>
45 #include <sys/arb.h>
46 #include <sys/module.h>
47 #include <sys/kernel.h>
48 #ifdef TCP_HHOOK
49 #include <sys/hhook.h>
50 #endif
51 #include <sys/malloc.h>
52 #include <sys/mbuf.h>
53 #include <sys/proc.h>
54 #include <sys/socket.h>
55 #include <sys/socketvar.h>
56 #ifdef KERN_TLS
57 #include <sys/ktls.h>
58 #endif
59 #include <sys/sysctl.h>
60 #include <sys/systm.h>
61 #ifdef STATS
62 #include <sys/qmath.h>
63 #include <sys/tree.h>
64 #include <sys/stats.h> /* Must come after qmath.h and tree.h */
65 #endif
66 #include <sys/refcount.h>
67 #include <sys/queue.h>
68 #include <sys/eventhandler.h>
69 #include <sys/smp.h>
70 #include <sys/kthread.h>
71 #include <sys/lock.h>
72 #include <sys/mutex.h>
73 #include <sys/tim_filter.h>
74 #include <sys/time.h>
75 #include <vm/uma.h>
76 #include <sys/kern_prefetch.h>
77 
78 #include <net/route.h>
79 #include <net/route/nhop.h>
80 #include <net/vnet.h>
81 
82 #define TCPSTATES		/* for logging */
83 
84 #include <netinet/in.h>
85 #include <netinet/in_kdtrace.h>
86 #include <netinet/in_pcb.h>
87 #include <netinet/ip.h>
88 #include <netinet/ip_icmp.h>	/* required for icmp_var.h */
89 #include <netinet/icmp_var.h>	/* for ICMP_BANDLIM */
90 #include <netinet/ip_var.h>
91 #include <netinet/ip6.h>
92 #include <netinet6/in6_pcb.h>
93 #include <netinet6/ip6_var.h>
94 #define	TCPOUTFLAGS
95 #include <netinet/tcp.h>
96 #include <netinet/tcp_fsm.h>
97 #include <netinet/tcp_seq.h>
98 #include <netinet/tcp_timer.h>
99 #include <netinet/tcp_var.h>
100 #include <netinet/tcpip.h>
101 #include <netinet/tcp_hpts.h>
102 #include <netinet/cc/cc.h>
103 #include <netinet/tcp_log_buf.h>
104 #include <netinet/tcp_ratelimit.h>
105 #include <netinet/tcp_lro.h>
106 #ifdef TCPDEBUG
107 #include <netinet/tcp_debug.h>
108 #endif				/* TCPDEBUG */
109 #ifdef TCP_OFFLOAD
110 #include <netinet/tcp_offload.h>
111 #endif
112 #ifdef INET6
113 #include <netinet6/tcp6_var.h>
114 #endif
115 #include <netinet/tcp_fastopen.h>
116 
117 #include <netipsec/ipsec_support.h>
118 #include <net/if.h>
119 #include <net/if_var.h>
120 #include <net/ethernet.h>
121 
122 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
123 #include <netipsec/ipsec.h>
124 #include <netipsec/ipsec6.h>
125 #endif				/* IPSEC */
126 
127 #include <netinet/udp.h>
128 #include <netinet/udp_var.h>
129 #include <machine/in_cksum.h>
130 
131 #ifdef MAC
132 #include <security/mac/mac_framework.h>
133 #endif
134 
135 #include "sack_filter.h"
136 #include "tcp_bbr.h"
137 #include "rack_bbr_common.h"
138 uma_zone_t bbr_zone;
139 uma_zone_t bbr_pcb_zone;
140 
141 struct sysctl_ctx_list bbr_sysctl_ctx;
142 struct sysctl_oid *bbr_sysctl_root;
143 
144 #define	TCPT_RANGESET_NOSLOP(tv, value, tvmin, tvmax) do { \
145 	(tv) = (value); \
146 	if ((u_long)(tv) < (u_long)(tvmin)) \
147 		(tv) = (tvmin); \
148 	if ((u_long)(tv) > (u_long)(tvmax)) \
149 		(tv) = (tvmax); \
150 } while(0)
151 
152 /*#define BBR_INVARIANT 1*/
153 
154 /*
155  * initial window
156  */
157 static uint32_t bbr_def_init_win = 10;
158 static int32_t bbr_persist_min = 250000;	/* 250ms */
159 static int32_t bbr_persist_max = 1000000;	/* 1 Second */
160 static int32_t bbr_cwnd_may_shrink = 0;
161 static int32_t bbr_cwndtarget_rtt_touse = BBR_RTT_PROP;
162 static int32_t bbr_num_pktepo_for_del_limit = BBR_NUM_RTTS_FOR_DEL_LIMIT;
163 static int32_t bbr_hardware_pacing_limit = 8000;
164 static int32_t bbr_quanta = 3;	/* How much extra quanta do we get? */
165 static int32_t bbr_no_retran = 0;
166 
167 
168 static int32_t bbr_error_base_paceout = 10000; /* usec to pace */
169 static int32_t bbr_max_net_error_cnt = 10;
170 /* Should the following be dynamic too -- loss wise */
171 static int32_t bbr_rtt_gain_thresh = 0;
172 /* Measurement controls */
173 static int32_t bbr_use_google_algo = 1;
174 static int32_t bbr_ts_limiting = 1;
175 static int32_t bbr_ts_can_raise = 0;
176 static int32_t bbr_do_red = 600;
177 static int32_t bbr_red_scale = 20000;
178 static int32_t bbr_red_mul = 1;
179 static int32_t bbr_red_div = 2;
180 static int32_t bbr_red_growth_restrict = 1;
181 static int32_t  bbr_target_is_bbunit = 0;
182 static int32_t bbr_drop_limit = 0;
183 /*
184  * How much gain do we need to see to
185  * stay in startup?
186  */
187 static int32_t bbr_marks_rxt_sack_passed = 0;
188 static int32_t bbr_start_exit = 25;
189 static int32_t bbr_low_start_exit = 25;	/* When we are in reduced gain */
190 static int32_t bbr_startup_loss_thresh = 2000;	/* 20.00% loss */
191 static int32_t bbr_hptsi_max_mul = 1;	/* These two mul/div assure a min pacing */
192 static int32_t bbr_hptsi_max_div = 2;	/* time, 0 means turned off. We need this
193 					 * if we go back ever to where the pacer
194 					 * has priority over timers.
195 					 */
196 static int32_t bbr_policer_call_from_rack_to = 0;
197 static int32_t bbr_policer_detection_enabled = 1;
198 static int32_t bbr_min_measurements_req = 1;	/* We need at least 2
199 						 * measurments before we are
200 						 * "good" note that 2 == 1.
201 						 * This is because we use a >
202 						 * comparison. This means if
203 						 * min_measure was 0, it takes
204 						 * num-measures > min(0) and
205 						 * you get 1 measurement and
206 						 * you are good. Set to 1, you
207 						 * have to have two
208 						 * measurements (this is done
209 						 * to prevent it from being ok
210 						 * to have no measurements). */
211 static int32_t bbr_no_pacing_until = 4;
212 
213 static int32_t bbr_min_usec_delta = 20000;	/* 20,000 usecs */
214 static int32_t bbr_min_peer_delta = 20;		/* 20 units */
215 static int32_t bbr_delta_percent = 150;		/* 15.0 % */
216 
217 static int32_t bbr_target_cwnd_mult_limit = 8;
218 /*
219  * bbr_cwnd_min_val is the number of
220  * segments we hold to in the RTT probe
221  * state typically 4.
222  */
223 static int32_t bbr_cwnd_min_val = BBR_PROBERTT_NUM_MSS;
224 
225 
226 static int32_t bbr_cwnd_min_val_hs = BBR_HIGHSPEED_NUM_MSS;
227 
228 static int32_t bbr_gain_to_target = 1;
229 static int32_t bbr_gain_gets_extra_too = 1;
230 /*
231  * bbr_high_gain is the 2/ln(2) value we need
232  * to double the sending rate in startup. This
233  * is used for both cwnd and hptsi gain's.
234  */
235 static int32_t bbr_high_gain = BBR_UNIT * 2885 / 1000 + 1;
236 static int32_t bbr_startup_lower = BBR_UNIT * 1500 / 1000 + 1;
237 static int32_t bbr_use_lower_gain_in_startup = 1;
238 
239 /* thresholds for reduction on drain in sub-states/drain */
240 static int32_t bbr_drain_rtt = BBR_SRTT;
241 static int32_t bbr_drain_floor = 88;
242 static int32_t google_allow_early_out = 1;
243 static int32_t google_consider_lost = 1;
244 static int32_t bbr_drain_drop_mul = 4;
245 static int32_t bbr_drain_drop_div = 5;
246 static int32_t bbr_rand_ot = 50;
247 static int32_t bbr_can_force_probertt = 0;
248 static int32_t bbr_can_adjust_probertt = 1;
249 static int32_t bbr_probertt_sets_rtt = 0;
250 static int32_t bbr_can_use_ts_for_rtt = 1;
251 static int32_t bbr_is_ratio = 0;
252 static int32_t bbr_sub_drain_app_limit = 1;
253 static int32_t bbr_prtt_slam_cwnd = 1;
254 static int32_t bbr_sub_drain_slam_cwnd = 1;
255 static int32_t bbr_slam_cwnd_in_main_drain = 1;
256 static int32_t bbr_filter_len_sec = 6;	/* How long does the rttProp filter
257 					 * hold */
258 static uint32_t bbr_rtt_probe_limit = (USECS_IN_SECOND * 4);
259 /*
260  * bbr_drain_gain is the reverse of the high_gain
261  * designed to drain back out the standing queue
262  * that is formed in startup by causing a larger
263  * hptsi gain and thus drainging the packets
264  * in flight.
265  */
266 static int32_t bbr_drain_gain = BBR_UNIT * 1000 / 2885;
267 static int32_t bbr_rttprobe_gain = 192;
268 
269 /*
270  * The cwnd_gain is the default cwnd gain applied when
271  * calculating a target cwnd. Note that the cwnd is
272  * a secondary factor in the way BBR works (see the
273  * paper and think about it, it will take some time).
274  * Basically the hptsi_gain spreads the packets out
275  * so you never get more than BDP to the peer even
276  * if the cwnd is high. In our implemenation that
277  * means in non-recovery/retransmission scenarios
278  * cwnd will never be reached by the flight-size.
279  */
280 static int32_t bbr_cwnd_gain = BBR_UNIT * 2;
281 static int32_t bbr_tlp_type_to_use = BBR_SRTT;
282 static int32_t bbr_delack_time = 100000;	/* 100ms in useconds */
283 static int32_t bbr_sack_not_required = 0;	/* set to one to allow non-sack to use bbr */
284 static int32_t bbr_initial_bw_bps = 62500;	/* 500kbps in bytes ps */
285 static int32_t bbr_ignore_data_after_close = 1;
286 static int16_t bbr_hptsi_gain[] = {
287 	(BBR_UNIT *5 / 4),
288 	(BBR_UNIT * 3 / 4),
289 	BBR_UNIT,
290 	BBR_UNIT,
291 	BBR_UNIT,
292 	BBR_UNIT,
293 	BBR_UNIT,
294 	BBR_UNIT
295 };
296 int32_t bbr_use_rack_resend_cheat = 1;
297 int32_t bbr_sends_full_iwnd = 1;
298 
299 #define BBR_HPTSI_GAIN_MAX 8
300 /*
301  * The BBR module incorporates a number of
302  * TCP ideas that have been put out into the IETF
303  * over the last few years:
304  * - Yuchung Cheng's RACK TCP (for which its named) that
305  *    will stop us using the number of dup acks and instead
306  *    use time as the gage of when we retransmit.
307  * - Reorder Detection of RFC4737 and the Tail-Loss probe draft
308  *    of Dukkipati et.al.
309  * - Van Jacobson's et.al BBR.
310  *
311  * RACK depends on SACK, so if an endpoint arrives that
312  * cannot do SACK the state machine below will shuttle the
313  * connection back to using the "default" TCP stack that is
314  * in FreeBSD.
315  *
316  * To implement BBR and RACK the original TCP stack was first decomposed
317  * into a functional state machine with individual states
318  * for each of the possible TCP connection states. The do_segement
319  * functions role in life is to mandate the connection supports SACK
320  * initially and then assure that the RACK state matches the conenction
321  * state before calling the states do_segment function. Data processing
322  * of inbound segments also now happens in the hpts_do_segment in general
323  * with only one exception. This is so we can keep the connection on
324  * a single CPU.
325  *
326  * Each state is simplified due to the fact that the original do_segment
327  * has been decomposed and we *know* what state we are in (no
328  * switches on the state) and all tests for SACK are gone. This
329  * greatly simplifies what each state does.
330  *
331  * TCP output is also over-written with a new version since it
332  * must maintain the new rack scoreboard and has had hptsi
333  * integrated as a requirment. Still todo is to eliminate the
334  * use of the callout_() system and use the hpts for all
335  * timers as well.
336  */
337 static uint32_t bbr_rtt_probe_time = 200000;	/* 200ms in micro seconds */
338 static uint32_t bbr_rtt_probe_cwndtarg = 4;	/* How many mss's outstanding */
339 static const int32_t bbr_min_req_free = 2;	/* The min we must have on the
340 						 * free list */
341 static int32_t bbr_tlp_thresh = 1;
342 static int32_t bbr_reorder_thresh = 2;
343 static int32_t bbr_reorder_fade = 60000000;	/* 0 - never fade, def
344 						 * 60,000,000 - 60 seconds */
345 static int32_t bbr_pkt_delay = 1000;
346 static int32_t bbr_min_to = 1000;	/* Number of usec's minimum timeout */
347 static int32_t bbr_incr_timers = 1;
348 
349 static int32_t bbr_tlp_min = 10000;	/* 10ms in usecs */
350 static int32_t bbr_delayed_ack_time = 200000;	/* 200ms in usecs */
351 static int32_t bbr_exit_startup_at_loss = 1;
352 
353 /*
354  * bbr_lt_bw_ratio is 1/8th
355  * bbr_lt_bw_diff is  < 4 Kbit/sec
356  */
357 static uint64_t bbr_lt_bw_diff = 4000 / 8;	/* In bytes per second */
358 static uint64_t bbr_lt_bw_ratio = 8;	/* For 1/8th */
359 static uint32_t bbr_lt_bw_max_rtts = 48;	/* How many rtt's do we use
360 						 * the lt_bw for */
361 static uint32_t bbr_lt_intvl_min_rtts = 4;	/* Min num of RTT's to measure
362 						 * lt_bw */
363 static int32_t bbr_lt_intvl_fp = 0;		/* False positive epoch diff */
364 static int32_t bbr_lt_loss_thresh = 196;	/* Lost vs delivered % */
365 static int32_t bbr_lt_fd_thresh = 100;		/* false detection % */
366 
367 static int32_t bbr_verbose_logging = 0;
368 /*
369  * Currently regular tcp has a rto_min of 30ms
370  * the backoff goes 12 times so that ends up
371  * being a total of 122.850 seconds before a
372  * connection is killed.
373  */
374 static int32_t bbr_rto_min_ms = 30;	/* 30ms same as main freebsd */
375 static int32_t bbr_rto_max_sec = 4;	/* 4 seconds */
376 
377 /****************************************************/
378 /* DEFAULT TSO SIZING  (cpu performance impacting)  */
379 /****************************************************/
380 /* What amount is our formula using to get TSO size */
381 static int32_t bbr_hptsi_per_second = 1000;
382 
383 /*
384  * For hptsi under bbr_cross_over connections what is delay
385  * target 7ms (in usec) combined with a seg_max of 2
386  * gets us close to identical google behavior in
387  * TSO size selection (possibly more 1MSS sends).
388  */
389 static int32_t bbr_hptsi_segments_delay_tar = 7000;
390 
391 /* Does pacing delay include overhead's in its time calculations? */
392 static int32_t bbr_include_enet_oh = 0;
393 static int32_t bbr_include_ip_oh = 1;
394 static int32_t bbr_include_tcp_oh = 1;
395 static int32_t bbr_google_discount = 10;
396 
397 /* Do we use (nf mode) pkt-epoch to drive us or rttProp? */
398 static int32_t bbr_state_is_pkt_epoch = 0;
399 static int32_t bbr_state_drain_2_tar = 1;
400 /* What is the max the 0 - bbr_cross_over MBPS TSO target
401  * can reach using our delay target. Note that this
402  * value becomes the floor for the cross over
403  * algorithm.
404  */
405 static int32_t bbr_hptsi_segments_max = 2;
406 static int32_t bbr_hptsi_segments_floor = 1;
407 static int32_t bbr_hptsi_utter_max = 0;
408 
409 /* What is the min the 0 - bbr_cross-over MBPS  TSO target can be */
410 static int32_t bbr_hptsi_bytes_min = 1460;
411 static int32_t bbr_all_get_min = 0;
412 
413 /* Cross over point from algo-a to algo-b */
414 static uint32_t bbr_cross_over = TWENTY_THREE_MBPS;
415 
416 /* Do we deal with our restart state? */
417 static int32_t bbr_uses_idle_restart = 0;
418 static int32_t bbr_idle_restart_threshold = 100000;	/* 100ms in useconds */
419 
420 /* Do we allow hardware pacing? */
421 static int32_t bbr_allow_hdwr_pacing = 0;
422 static int32_t bbr_hdwr_pace_adjust = 2;	/* multipler when we calc the tso size */
423 static int32_t bbr_hdwr_pace_floor = 1;
424 static int32_t bbr_hdwr_pacing_delay_cnt = 10;
425 
426 /****************************************************/
427 static int32_t bbr_resends_use_tso = 0;
428 static int32_t bbr_tlp_max_resend = 2;
429 static int32_t bbr_sack_block_limit = 128;
430 
431 #define  BBR_MAX_STAT 19
432 counter_u64_t bbr_state_time[BBR_MAX_STAT];
433 counter_u64_t bbr_state_lost[BBR_MAX_STAT];
434 counter_u64_t bbr_state_resend[BBR_MAX_STAT];
435 counter_u64_t bbr_stat_arry[BBR_STAT_SIZE];
436 counter_u64_t bbr_opts_arry[BBR_OPTS_SIZE];
437 counter_u64_t bbr_out_size[TCP_MSS_ACCT_SIZE];
438 counter_u64_t bbr_flows_whdwr_pacing;
439 counter_u64_t bbr_flows_nohdwr_pacing;
440 
441 counter_u64_t bbr_nohdwr_pacing_enobuf;
442 counter_u64_t bbr_hdwr_pacing_enobuf;
443 
444 static inline uint64_t bbr_get_bw(struct tcp_bbr *bbr);
445 
446 /*
447  * Static defintions we need for forward declarations.
448  */
449 static uint32_t
450 bbr_get_pacing_length(struct tcp_bbr *bbr, uint16_t gain,
451     uint32_t useconds_time, uint64_t bw);
452 static uint32_t
453 bbr_get_a_state_target(struct tcp_bbr *bbr, uint32_t gain);
454 static void
455      bbr_set_state(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t win);
456 static void
457 bbr_set_probebw_gains(struct tcp_bbr *bbr,  uint32_t cts, uint32_t losses);
458 static void
459 bbr_substate_change(struct tcp_bbr *bbr, uint32_t cts, int line,
460 		    int dolog);
461 static uint32_t
462 bbr_get_target_cwnd(struct tcp_bbr *bbr, uint64_t bw, uint32_t gain);
463 static void
464 bbr_state_change(struct tcp_bbr *bbr, uint32_t cts, int32_t epoch,
465 		 int32_t pkt_epoch, uint32_t losses);
466 static uint32_t
467 bbr_calc_thresh_rack(struct tcp_bbr *bbr, uint32_t srtt, uint32_t cts, struct bbr_sendmap *rsm);
468 static uint32_t bbr_initial_cwnd(struct tcp_bbr *bbr, struct tcpcb *tp);
469 static uint32_t
470 bbr_calc_thresh_tlp(struct tcpcb *tp, struct tcp_bbr *bbr,
471     struct bbr_sendmap *rsm, uint32_t srtt,
472     uint32_t cts);
473 static void
474 bbr_exit_persist(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts,
475     int32_t line);
476 static void
477      bbr_set_state_target(struct tcp_bbr *bbr, int line);
478 static void
479      bbr_enter_probe_rtt(struct tcp_bbr *bbr, uint32_t cts, int32_t line);
480 
481 static void
482      bbr_log_progress_event(struct tcp_bbr *bbr, struct tcpcb *tp, uint32_t tick, int event, int line);
483 
484 static void
485      tcp_bbr_tso_size_check(struct tcp_bbr *bbr, uint32_t cts);
486 
487 static void
488      bbr_setup_red_bw(struct tcp_bbr *bbr, uint32_t cts);
489 
490 static void
491      bbr_log_rtt_shrinks(struct tcp_bbr *bbr, uint32_t cts, uint32_t applied, uint32_t rtt,
492 			 uint32_t line, uint8_t is_start, uint16_t set);
493 
494 static struct bbr_sendmap *
495             bbr_find_lowest_rsm(struct tcp_bbr *bbr);
496 static __inline uint32_t
497 bbr_get_rtt(struct tcp_bbr *bbr, int32_t rtt_type);
498 static void
499      bbr_log_to_start(struct tcp_bbr *bbr, uint32_t cts, uint32_t to, int32_t slot, uint8_t which);
500 
501 static void
502 bbr_log_timer_var(struct tcp_bbr *bbr, int mode, uint32_t cts, uint32_t time_since_sent, uint32_t srtt,
503     uint32_t thresh, uint32_t to);
504 static void
505      bbr_log_hpts_diag(struct tcp_bbr *bbr, uint32_t cts, struct hpts_diag *diag);
506 
507 static void
508 bbr_log_type_bbrsnd(struct tcp_bbr *bbr, uint32_t len, uint32_t slot,
509     uint32_t del_by, uint32_t cts, uint32_t sloton, uint32_t prev_delay);
510 
511 static void
512 bbr_enter_persist(struct tcpcb *tp, struct tcp_bbr *bbr,
513     uint32_t cts, int32_t line);
514 static void
515      bbr_stop_all_timers(struct tcpcb *tp);
516 static void
517      bbr_exit_probe_rtt(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts);
518 static void
519      bbr_check_probe_rtt_limits(struct tcp_bbr *bbr, uint32_t cts);
520 static void
521      bbr_timer_cancel(struct tcp_bbr *bbr, int32_t line, uint32_t cts);
522 
523 
524 static void
525 bbr_log_pacing_delay_calc(struct tcp_bbr *bbr, uint16_t gain, uint32_t len,
526     uint32_t cts, uint32_t usecs, uint64_t bw, uint32_t override, int mod);
527 
528 static inline uint8_t
529 bbr_state_val(struct tcp_bbr *bbr)
530 {
531 	return(bbr->rc_bbr_substate);
532 }
533 
534 static inline uint32_t
535 get_min_cwnd(struct tcp_bbr *bbr)
536 {
537 	int mss;
538 
539 	mss = min((bbr->rc_tp->t_maxseg - bbr->rc_last_options), bbr->r_ctl.rc_pace_max_segs);
540 	if (bbr_get_rtt(bbr, BBR_RTT_PROP) < BBR_HIGH_SPEED)
541 		return (bbr_cwnd_min_val_hs * mss);
542 	else
543 		return (bbr_cwnd_min_val * mss);
544 }
545 
546 static uint32_t
547 bbr_get_persists_timer_val(struct tcpcb *tp, struct tcp_bbr *bbr)
548 {
549 	uint64_t srtt, var;
550 	uint64_t ret_val;
551 
552 	bbr->r_ctl.rc_hpts_flags |= PACE_TMR_PERSIT;
553 	if (tp->t_srtt == 0) {
554 		srtt = (uint64_t)BBR_INITIAL_RTO;
555 		var = 0;
556 	} else {
557 		srtt = ((uint64_t)TICKS_2_USEC(tp->t_srtt) >> TCP_RTT_SHIFT);
558 		var = ((uint64_t)TICKS_2_USEC(tp->t_rttvar) >> TCP_RTT_SHIFT);
559 	}
560 	TCPT_RANGESET_NOSLOP(ret_val, ((srtt + var) * tcp_backoff[tp->t_rxtshift]),
561 	    bbr_persist_min, bbr_persist_max);
562 	return ((uint32_t)ret_val);
563 }
564 
565 static uint32_t
566 bbr_timer_start(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
567 {
568 	/*
569 	 * Start the FR timer, we do this based on getting the first one in
570 	 * the rc_tmap. Note that if its NULL we must stop the timer. in all
571 	 * events we need to stop the running timer (if its running) before
572 	 * starting the new one.
573 	 */
574 	uint32_t thresh, exp, to, srtt, time_since_sent, tstmp_touse;
575 	int32_t idx;
576 	int32_t is_tlp_timer = 0;
577 	struct bbr_sendmap *rsm;
578 
579 	if (bbr->rc_all_timers_stopped) {
580 		/* All timers have been stopped none are to run */
581 		return (0);
582 	}
583 	if (bbr->rc_in_persist) {
584 		/* We can't start any timer in persists */
585 		return (bbr_get_persists_timer_val(tp, bbr));
586 	}
587 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_tmap);
588 	if ((rsm == NULL) ||
589 	    ((tp->t_flags & TF_SACK_PERMIT) == 0) ||
590 	    (tp->t_state < TCPS_ESTABLISHED)) {
591 		/* Nothing on the send map */
592 activate_rxt:
593 		if (SEQ_LT(tp->snd_una, tp->snd_max) || sbavail(&(tp->t_inpcb->inp_socket->so_snd))) {
594 			uint64_t tov;
595 
596 			time_since_sent = 0;
597 			rsm = TAILQ_FIRST(&bbr->r_ctl.rc_tmap);
598 			if (rsm) {
599 				idx = rsm->r_rtr_cnt - 1;
600 				if (TSTMP_GEQ(rsm->r_tim_lastsent[idx], bbr->r_ctl.rc_tlp_rxt_last_time))
601 					tstmp_touse = rsm->r_tim_lastsent[idx];
602 				else
603 					tstmp_touse = bbr->r_ctl.rc_tlp_rxt_last_time;
604 				if (TSTMP_GT(tstmp_touse, cts))
605 				    time_since_sent = cts - tstmp_touse;
606 			}
607 			bbr->r_ctl.rc_hpts_flags |= PACE_TMR_RXT;
608 			if (tp->t_srtt == 0)
609 				tov = BBR_INITIAL_RTO;
610 			else
611 				tov = ((uint64_t)(TICKS_2_USEC(tp->t_srtt) +
612 				    ((uint64_t)TICKS_2_USEC(tp->t_rttvar) * (uint64_t)4)) >> TCP_RTT_SHIFT);
613 			if (tp->t_rxtshift)
614 				tov *= tcp_backoff[tp->t_rxtshift];
615 			if (tov > time_since_sent)
616 				tov -= time_since_sent;
617 			else
618 				tov = bbr->r_ctl.rc_min_to;
619 			TCPT_RANGESET_NOSLOP(to, tov,
620 			    (bbr->r_ctl.rc_min_rto_ms * MS_IN_USEC),
621 			    (bbr->rc_max_rto_sec * USECS_IN_SECOND));
622 			bbr_log_timer_var(bbr, 2, cts, 0, srtt, 0, to);
623 			return (to);
624 		}
625 		return (0);
626 	}
627 	if (rsm->r_flags & BBR_ACKED) {
628 		rsm = bbr_find_lowest_rsm(bbr);
629 		if (rsm == NULL) {
630 			/* No lowest? */
631 			goto activate_rxt;
632 		}
633 	}
634 	/* Convert from ms to usecs */
635 	if (rsm->r_flags & BBR_SACK_PASSED) {
636 		if ((tp->t_flags & TF_SENTFIN) &&
637 		    ((tp->snd_max - tp->snd_una) == 1) &&
638 		    (rsm->r_flags & BBR_HAS_FIN)) {
639 			/*
640 			 * We don't start a bbr rack timer if all we have is
641 			 * a FIN outstanding.
642 			 */
643 			goto activate_rxt;
644 		}
645 		srtt = bbr_get_rtt(bbr, BBR_RTT_RACK);
646 		thresh = bbr_calc_thresh_rack(bbr, srtt, cts, rsm);
647 		idx = rsm->r_rtr_cnt - 1;
648 		exp = rsm->r_tim_lastsent[idx] + thresh;
649 		if (SEQ_GEQ(exp, cts)) {
650 			to = exp - cts;
651 			if (to < bbr->r_ctl.rc_min_to) {
652 				to = bbr->r_ctl.rc_min_to;
653 			}
654 		} else {
655 			to = bbr->r_ctl.rc_min_to;
656 		}
657 	} else {
658 		/* Ok we need to do a TLP not RACK */
659 		if (bbr->rc_tlp_in_progress != 0) {
660 			/*
661 			 * The previous send was a TLP.
662 			 */
663 			goto activate_rxt;
664 		}
665 		rsm = TAILQ_LAST_FAST(&bbr->r_ctl.rc_tmap, bbr_sendmap, r_tnext);
666 		if (rsm == NULL) {
667 			/* We found no rsm to TLP with. */
668 			goto activate_rxt;
669 		}
670 		if (rsm->r_flags & BBR_HAS_FIN) {
671 			/* If its a FIN we don't do TLP */
672 			rsm = NULL;
673 			goto activate_rxt;
674 		}
675 		time_since_sent = 0;
676 		idx = rsm->r_rtr_cnt - 1;
677 		if (TSTMP_GEQ(rsm->r_tim_lastsent[idx], bbr->r_ctl.rc_tlp_rxt_last_time))
678 			tstmp_touse = rsm->r_tim_lastsent[idx];
679 		else
680 			tstmp_touse = bbr->r_ctl.rc_tlp_rxt_last_time;
681 		if (TSTMP_GT(tstmp_touse, cts))
682 		    time_since_sent = cts - tstmp_touse;
683 		is_tlp_timer = 1;
684 		srtt = bbr_get_rtt(bbr, bbr_tlp_type_to_use);
685 		thresh = bbr_calc_thresh_tlp(tp, bbr, rsm, srtt, cts);
686 		if (thresh > time_since_sent)
687 			to = thresh - time_since_sent;
688 		else
689 			to = bbr->r_ctl.rc_min_to;
690 		if (to > (((uint32_t)bbr->rc_max_rto_sec) * USECS_IN_SECOND)) {
691 			/*
692 			 * If the TLP time works out to larger than the max
693 			 * RTO lets not do TLP.. just RTO.
694 			 */
695 			goto activate_rxt;
696 		}
697 		if ((bbr->rc_tlp_rtx_out == 1) &&
698 		    (rsm->r_start == bbr->r_ctl.rc_last_tlp_seq)) {
699 			/*
700 			 * Second retransmit of the same TLP
701 			 * lets not.
702 			 */
703 			bbr->rc_tlp_rtx_out = 0;
704 			goto activate_rxt;
705 		}
706 		if (rsm->r_start != bbr->r_ctl.rc_last_tlp_seq) {
707 			/*
708 			 * The tail is no longer the last one I did a probe
709 			 * on
710 			 */
711 			bbr->r_ctl.rc_tlp_seg_send_cnt = 0;
712 			bbr->r_ctl.rc_last_tlp_seq = rsm->r_start;
713 		}
714 	}
715 	if (is_tlp_timer == 0) {
716 		BBR_STAT_INC(bbr_to_arm_rack);
717 		bbr->r_ctl.rc_hpts_flags |= PACE_TMR_RACK;
718 	} else {
719 		bbr_log_timer_var(bbr, 1, cts, time_since_sent, srtt, thresh, to);
720 		if (bbr->r_ctl.rc_tlp_seg_send_cnt > bbr_tlp_max_resend) {
721 			/*
722 			 * We have exceeded how many times we can retran the
723 			 * current TLP timer, switch to the RTO timer.
724 			 */
725 			goto activate_rxt;
726 		} else {
727 			BBR_STAT_INC(bbr_to_arm_tlp);
728 			bbr->r_ctl.rc_hpts_flags |= PACE_TMR_TLP;
729 		}
730 	}
731 	return (to);
732 }
733 
734 static inline int32_t
735 bbr_minseg(struct tcp_bbr *bbr)
736 {
737 	return (bbr->r_ctl.rc_pace_min_segs - bbr->rc_last_options);
738 }
739 
740 static void
741 bbr_start_hpts_timer(struct tcp_bbr *bbr, struct tcpcb *tp, uint32_t cts, int32_t frm, int32_t slot, uint32_t tot_len)
742 {
743 	struct inpcb *inp;
744 	struct hpts_diag diag;
745 	uint32_t delayed_ack = 0;
746 	uint32_t left = 0;
747 	uint32_t hpts_timeout;
748 	uint8_t stopped;
749 	int32_t delay_calc = 0;
750 	uint32_t prev_delay = 0;
751 
752 	inp = tp->t_inpcb;
753 	if (inp->inp_in_hpts) {
754 		/* A previous call is already set up */
755 		return;
756 	}
757 	if ((tp->t_state == TCPS_CLOSED) ||
758 	    (tp->t_state == TCPS_LISTEN)) {
759 		return;
760 	}
761 	stopped = bbr->rc_tmr_stopped;
762 	if (stopped && TSTMP_GT(bbr->r_ctl.rc_timer_exp, cts)) {
763 		left = bbr->r_ctl.rc_timer_exp - cts;
764 	}
765 	bbr->r_ctl.rc_hpts_flags = 0;
766 	bbr->r_ctl.rc_timer_exp = 0;
767 	prev_delay = bbr->r_ctl.rc_last_delay_val;
768 	if (bbr->r_ctl.rc_last_delay_val &&
769 	    (slot == 0)) {
770 		/*
771 		 * If a previous pacer delay was in place we
772 		 * are not coming from the output side (where
773 		 * we calculate a delay, more likely a timer).
774 		 */
775 		slot = bbr->r_ctl.rc_last_delay_val;
776 		if (TSTMP_GT(cts, bbr->rc_pacer_started)) {
777 			/* Compensate for time passed  */
778 			delay_calc = cts - bbr->rc_pacer_started;
779 			if (delay_calc <= slot)
780 				slot -= delay_calc;
781 		}
782 	}
783 	/* Do we have early to make up for by pushing out the pacing time? */
784 	if (bbr->r_agg_early_set) {
785 		bbr_log_pacing_delay_calc(bbr, 0, bbr->r_ctl.rc_agg_early, cts, slot, 0, bbr->r_agg_early_set, 2);
786 		slot += bbr->r_ctl.rc_agg_early;
787 		bbr->r_ctl.rc_agg_early = 0;
788 		bbr->r_agg_early_set = 0;
789 	}
790 	/* Are we running a total debt that needs to be compensated for? */
791 	if (bbr->r_ctl.rc_hptsi_agg_delay) {
792 		if (slot > bbr->r_ctl.rc_hptsi_agg_delay) {
793 			/* We nuke the delay */
794 			slot -= bbr->r_ctl.rc_hptsi_agg_delay;
795 			bbr->r_ctl.rc_hptsi_agg_delay = 0;
796 		} else {
797 			/* We nuke some of the delay, put in a minimal 100usecs  */
798 			bbr->r_ctl.rc_hptsi_agg_delay -= slot;
799 			bbr->r_ctl.rc_last_delay_val = slot = 100;
800 		}
801 	}
802 	bbr->r_ctl.rc_last_delay_val = slot;
803 	hpts_timeout = bbr_timer_start(tp, bbr, cts);
804 	if (tp->t_flags & TF_DELACK) {
805 		if (bbr->rc_in_persist == 0) {
806 			delayed_ack = bbr_delack_time;
807 		} else {
808 			/*
809 			 * We are in persists and have
810 			 * gotten a new data element.
811 			 */
812 			if (hpts_timeout > bbr_delack_time) {
813 				/*
814 				 * Lets make the persists timer (which acks)
815 				 * be the smaller of hpts_timeout and bbr_delack_time.
816 				 */
817 				hpts_timeout = bbr_delack_time;
818 			}
819 		}
820 	}
821 	if (delayed_ack &&
822 	    ((hpts_timeout == 0) ||
823 	     (delayed_ack < hpts_timeout))) {
824 		/* We need a Delayed ack timer */
825 		bbr->r_ctl.rc_hpts_flags = PACE_TMR_DELACK;
826 		hpts_timeout = delayed_ack;
827 	}
828 	if (slot) {
829 		/* Mark that we have a pacing timer up */
830 		BBR_STAT_INC(bbr_paced_segments);
831 		bbr->r_ctl.rc_hpts_flags |= PACE_PKT_OUTPUT;
832 	}
833 	/*
834 	 * If no timers are going to run and we will fall off thfe hptsi
835 	 * wheel, we resort to a keep-alive timer if its configured.
836 	 */
837 	if ((hpts_timeout == 0) &&
838 	    (slot == 0)) {
839 		if ((V_tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
840 		    (tp->t_state <= TCPS_CLOSING)) {
841 			/*
842 			 * Ok we have no timer (persists, rack, tlp, rxt  or
843 			 * del-ack), we don't have segments being paced. So
844 			 * all that is left is the keepalive timer.
845 			 */
846 			if (TCPS_HAVEESTABLISHED(tp->t_state)) {
847 				hpts_timeout = TICKS_2_USEC(TP_KEEPIDLE(tp));
848 			} else {
849 				hpts_timeout = TICKS_2_USEC(TP_KEEPINIT(tp));
850 			}
851 			bbr->r_ctl.rc_hpts_flags |= PACE_TMR_KEEP;
852 		}
853 	}
854 	if (left && (stopped & (PACE_TMR_KEEP | PACE_TMR_DELACK)) ==
855 	    (bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK)) {
856 		/*
857 		 * RACK, TLP, persists and RXT timers all are restartable
858 		 * based on actions input .. i.e we received a packet (ack
859 		 * or sack) and that changes things (rw, or snd_una etc).
860 		 * Thus we can restart them with a new value. For
861 		 * keep-alive, delayed_ack we keep track of what was left
862 		 * and restart the timer with a smaller value.
863 		 */
864 		if (left < hpts_timeout)
865 			hpts_timeout = left;
866 	}
867 	if (bbr->r_ctl.rc_incr_tmrs && slot &&
868 	    (bbr->r_ctl.rc_hpts_flags & (PACE_TMR_TLP|PACE_TMR_RXT))) {
869 		/*
870 		 * If configured to do so, and the timer is either
871 		 * the TLP or RXT timer, we need to increase the timeout
872 		 * by the pacing time. Consider the bottleneck at my
873 		 * machine as an example, we are sending something
874 		 * to start a TLP on. The last packet won't be emitted
875 		 * fully until the pacing time (the bottleneck will hold
876 		 * the data in place). Once the packet is emitted that
877 		 * is when we want to start waiting for the TLP. This
878 		 * is most evident with hardware pacing (where the nic
879 		 * is holding the packet(s) before emitting). But it
880 		 * can also show up in the network so we do it for all
881 		 * cases. Technically we would take off one packet from
882 		 * this extra delay but this is easier and being more
883 		 * conservative is probably better.
884 		 */
885 		hpts_timeout += slot;
886 	}
887 	if (hpts_timeout) {
888 		/*
889 		 * Hack alert for now we can't time-out over 2147 seconds (a
890 		 * bit more than 35min)
891 		 */
892 		if (hpts_timeout > 0x7ffffffe)
893 			hpts_timeout = 0x7ffffffe;
894 		bbr->r_ctl.rc_timer_exp = cts + hpts_timeout;
895 	} else
896 		bbr->r_ctl.rc_timer_exp = 0;
897 	if ((slot) &&
898 	    (bbr->rc_use_google ||
899 	     bbr->output_error_seen ||
900 	     (slot <= hpts_timeout))  ) {
901 		/*
902 		 * Tell LRO that it can queue packets while
903 		 * we pace.
904 		 */
905 		bbr->rc_inp->inp_flags2 |= INP_MBUF_QUEUE_READY;
906 		if ((bbr->r_ctl.rc_hpts_flags & PACE_TMR_RACK) &&
907 		    (bbr->rc_cwnd_limited == 0)) {
908 			/*
909 			 * If we are not cwnd limited and we
910 			 * are running a rack timer we put on
911 			 * the do not disturbe even for sack.
912 			 */
913 			inp->inp_flags2 |= INP_DONT_SACK_QUEUE;
914 		} else
915 			inp->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
916 		bbr->rc_pacer_started = cts;
917 
918 		(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_USEC_TO_SLOTS(slot),
919 					   __LINE__, &diag);
920 		bbr->rc_timer_first = 0;
921 		bbr->bbr_timer_src = frm;
922 		bbr_log_to_start(bbr, cts, hpts_timeout, slot, 1);
923 		bbr_log_hpts_diag(bbr, cts, &diag);
924 	} else if (hpts_timeout) {
925 		(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_USEC_TO_SLOTS(hpts_timeout),
926 					   __LINE__, &diag);
927 		/*
928 		 * We add the flag here as well if the slot is set,
929 		 * since hpts will call in to clear the queue first before
930 		 * calling the output routine (which does our timers).
931 		 * We don't want to set the flag if its just a timer
932 		 * else the arrival of data might (that causes us
933 		 * to send more) might get delayed. Imagine being
934 		 * on a keep-alive timer and a request comes in for
935 		 * more data.
936 		 */
937 		if (slot)
938 			bbr->rc_pacer_started = cts;
939 		if ((bbr->r_ctl.rc_hpts_flags & PACE_TMR_RACK) &&
940 		    (bbr->rc_cwnd_limited == 0)) {
941 			/*
942 			 * For a rack timer, don't wake us even
943 			 * if a sack arrives as long as we are
944 			 * not cwnd limited.
945 			 */
946 			bbr->rc_inp->inp_flags2 |= INP_MBUF_QUEUE_READY;
947 			inp->inp_flags2 |= INP_DONT_SACK_QUEUE;
948 		} else {
949 			/* All other timers wake us up */
950 			bbr->rc_inp->inp_flags2 &= ~INP_MBUF_QUEUE_READY;
951 			inp->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
952 		}
953 		bbr->bbr_timer_src = frm;
954 		bbr_log_to_start(bbr, cts, hpts_timeout, slot, 0);
955 		bbr_log_hpts_diag(bbr, cts, &diag);
956 		bbr->rc_timer_first = 1;
957 	}
958 	bbr->rc_tmr_stopped = 0;
959 	bbr_log_type_bbrsnd(bbr, tot_len, slot, delay_calc, cts, frm, prev_delay);
960 }
961 
962 static void
963 bbr_timer_audit(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts, struct sockbuf *sb)
964 {
965 	/*
966 	 * We received an ack, and then did not call send or were bounced
967 	 * out due to the hpts was running. Now a timer is up as well, is it
968 	 * the right timer?
969 	 */
970 	struct inpcb *inp;
971 	struct bbr_sendmap *rsm;
972 	uint32_t hpts_timeout;
973 	int tmr_up;
974 
975 	tmr_up = bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK;
976 	if (bbr->rc_in_persist && (tmr_up == PACE_TMR_PERSIT))
977 		return;
978 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_tmap);
979 	if (((rsm == NULL) || (tp->t_state < TCPS_ESTABLISHED)) &&
980 	    (tmr_up == PACE_TMR_RXT)) {
981 		/* Should be an RXT */
982 		return;
983 	}
984 	inp = bbr->rc_inp;
985 	if (rsm == NULL) {
986 		/* Nothing outstanding? */
987 		if (tp->t_flags & TF_DELACK) {
988 			if (tmr_up == PACE_TMR_DELACK)
989 				/*
990 				 * We are supposed to have delayed ack up
991 				 * and we do
992 				 */
993 				return;
994 		} else if (sbavail(&inp->inp_socket->so_snd) &&
995 		    (tmr_up == PACE_TMR_RXT)) {
996 			/*
997 			 * if we hit enobufs then we would expect the
998 			 * possiblity of nothing outstanding and the RXT up
999 			 * (and the hptsi timer).
1000 			 */
1001 			return;
1002 		} else if (((V_tcp_always_keepalive ||
1003 			    inp->inp_socket->so_options & SO_KEEPALIVE) &&
1004 			    (tp->t_state <= TCPS_CLOSING)) &&
1005 			    (tmr_up == PACE_TMR_KEEP) &&
1006 		    (tp->snd_max == tp->snd_una)) {
1007 			/* We should have keep alive up and we do */
1008 			return;
1009 		}
1010 	}
1011 	if (rsm && (rsm->r_flags & BBR_SACK_PASSED)) {
1012 		if ((tp->t_flags & TF_SENTFIN) &&
1013 		    ((tp->snd_max - tp->snd_una) == 1) &&
1014 		    (rsm->r_flags & BBR_HAS_FIN)) {
1015 			/* needs to be a RXT */
1016 			if (tmr_up == PACE_TMR_RXT)
1017 				return;
1018 			else
1019 				goto wrong_timer;
1020 		} else if (tmr_up == PACE_TMR_RACK)
1021 			return;
1022 		else
1023 			goto wrong_timer;
1024 	} else if (rsm && (tmr_up == PACE_TMR_RACK)) {
1025 		/* Rack timer has priority if we have data out */
1026 		return;
1027 	} else if (SEQ_GT(tp->snd_max, tp->snd_una) &&
1028 		    ((tmr_up == PACE_TMR_TLP) ||
1029 	    (tmr_up == PACE_TMR_RXT))) {
1030 		/*
1031 		 * Either a TLP or RXT is fine if no sack-passed is in place
1032 		 * and data is outstanding.
1033 		 */
1034 		return;
1035 	} else if (tmr_up == PACE_TMR_DELACK) {
1036 		/*
1037 		 * If the delayed ack was going to go off before the
1038 		 * rtx/tlp/rack timer were going to expire, then that would
1039 		 * be the timer in control. Note we don't check the time
1040 		 * here trusting the code is correct.
1041 		 */
1042 		return;
1043 	}
1044 	if (SEQ_GT(tp->snd_max, tp->snd_una) &&
1045 	    ((tmr_up == PACE_TMR_RXT) ||
1046 	     (tmr_up == PACE_TMR_TLP) ||
1047 	     (tmr_up == PACE_TMR_RACK))) {
1048 		/*
1049 		 * We have outstanding data and
1050 		 * we *do* have a RACK, TLP or RXT
1051 		 * timer running. We won't restart
1052 		 * anything here since thats probably ok we
1053 		 * will get called with some timer here shortly.
1054 		 */
1055 		return;
1056 	}
1057 	/*
1058 	 * Ok the timer originally started is not what we want now. We will
1059 	 * force the hpts to be stopped if any, and restart with the slot
1060 	 * set to what was in the saved slot.
1061 	 */
1062 wrong_timer:
1063 	if ((bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0) {
1064 		if (inp->inp_in_hpts)
1065 			tcp_hpts_remove(inp, HPTS_REMOVE_OUTPUT);
1066 		bbr_timer_cancel(bbr, __LINE__, cts);
1067 		bbr_start_hpts_timer(bbr, tp, cts, 1, bbr->r_ctl.rc_last_delay_val,
1068 		    0);
1069 	} else {
1070 		/*
1071 		 * Output is hptsi so we just need to switch the type of
1072 		 * timer. We don't bother with keep-alive, since when we
1073 		 * jump through the output, it will start the keep-alive if
1074 		 * nothing is sent.
1075 		 *
1076 		 * We only need a delayed-ack added and or the hpts_timeout.
1077 		 */
1078 		hpts_timeout = bbr_timer_start(tp, bbr, cts);
1079 		if (tp->t_flags & TF_DELACK) {
1080 			if (hpts_timeout == 0) {
1081 				hpts_timeout = bbr_delack_time;
1082 				bbr->r_ctl.rc_hpts_flags = PACE_TMR_DELACK;
1083 			}
1084 			else if (hpts_timeout > bbr_delack_time) {
1085 				hpts_timeout = bbr_delack_time;
1086 				bbr->r_ctl.rc_hpts_flags = PACE_TMR_DELACK;
1087 			}
1088 		}
1089 		if (hpts_timeout) {
1090 			if (hpts_timeout > 0x7ffffffe)
1091 				hpts_timeout = 0x7ffffffe;
1092 			bbr->r_ctl.rc_timer_exp = cts + hpts_timeout;
1093 		}
1094 	}
1095 }
1096 
1097 int32_t bbr_clear_lost = 0;
1098 
1099 /*
1100  * Considers the two time values now (cts) and earlier.
1101  * If cts is smaller than earlier, we could have
1102  * had a sequence wrap (our counter wraps every
1103  * 70 min or so) or it could be just clock skew
1104  * getting us two differnt time values. Clock skew
1105  * will show up within 10ms or so. So in such
1106  * a case (where cts is behind earlier time by
1107  * less than 10ms) we return 0. Otherwise we
1108  * return the true difference between them.
1109  */
1110 static inline uint32_t
1111 bbr_calc_time(uint32_t cts, uint32_t earlier_time) {
1112 	/*
1113 	 * Given two timestamps, the current time stamp cts, and some other
1114 	 * time-stamp taken in theory earlier return the difference. The
1115 	 * trick is here sometimes locking will get the other timestamp
1116 	 * after the cts. If this occurs we need to return 0.
1117 	 */
1118 	if (TSTMP_GEQ(cts, earlier_time))
1119 		return (cts - earlier_time);
1120 	/*
1121 	 * cts is behind earlier_time if its less than 10ms consider it 0.
1122 	 * If its more than 10ms difference then we had a time wrap. Else
1123 	 * its just the normal locking foo. I wonder if we should not go to
1124 	 * 64bit TS and get rid of this issue.
1125 	 */
1126 	if (TSTMP_GEQ((cts + 10000), earlier_time))
1127 		return (0);
1128 	/*
1129 	 * Ok the time must have wrapped. So we need to answer a large
1130 	 * amount of time, which the normal subtraction should do.
1131 	 */
1132 	return (cts - earlier_time);
1133 }
1134 
1135 
1136 
1137 static int
1138 sysctl_bbr_clear_lost(SYSCTL_HANDLER_ARGS)
1139 {
1140 	uint32_t stat;
1141 	int32_t error;
1142 
1143 	error = SYSCTL_OUT(req, &bbr_clear_lost, sizeof(uint32_t));
1144 	if (error || req->newptr == NULL)
1145 		return error;
1146 
1147 	error = SYSCTL_IN(req, &stat, sizeof(uint32_t));
1148 	if (error)
1149 		return (error);
1150 	if (stat == 1) {
1151 #ifdef BBR_INVARIANTS
1152 		printf("Clearing BBR lost counters\n");
1153 #endif
1154 		COUNTER_ARRAY_ZERO(bbr_state_lost, BBR_MAX_STAT);
1155 		COUNTER_ARRAY_ZERO(bbr_state_time, BBR_MAX_STAT);
1156 		COUNTER_ARRAY_ZERO(bbr_state_resend, BBR_MAX_STAT);
1157 	} else if (stat == 2) {
1158 #ifdef BBR_INVARIANTS
1159 		printf("Clearing BBR option counters\n");
1160 #endif
1161 		COUNTER_ARRAY_ZERO(bbr_opts_arry, BBR_OPTS_SIZE);
1162 	} else if (stat == 3) {
1163 #ifdef BBR_INVARIANTS
1164 		printf("Clearing BBR stats counters\n");
1165 #endif
1166 		COUNTER_ARRAY_ZERO(bbr_stat_arry, BBR_STAT_SIZE);
1167 	} else if (stat == 4) {
1168 #ifdef BBR_INVARIANTS
1169 		printf("Clearing BBR out-size counters\n");
1170 #endif
1171 		COUNTER_ARRAY_ZERO(bbr_out_size, TCP_MSS_ACCT_SIZE);
1172 	}
1173 	bbr_clear_lost = 0;
1174 	return (0);
1175 }
1176 
1177 static void
1178 bbr_init_sysctls(void)
1179 {
1180 	struct sysctl_oid *bbr_probertt;
1181 	struct sysctl_oid *bbr_hptsi;
1182 	struct sysctl_oid *bbr_measure;
1183 	struct sysctl_oid *bbr_cwnd;
1184 	struct sysctl_oid *bbr_timeout;
1185 	struct sysctl_oid *bbr_states;
1186 	struct sysctl_oid *bbr_startup;
1187 	struct sysctl_oid *bbr_policer;
1188 
1189 	/* Probe rtt controls */
1190 	bbr_probertt = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1191 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1192 	    OID_AUTO,
1193 	    "probertt",
1194 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1195 	    "");
1196 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1197 	    SYSCTL_CHILDREN(bbr_probertt),
1198 	    OID_AUTO, "gain", CTLFLAG_RW,
1199 	    &bbr_rttprobe_gain, 192,
1200 	    "What is the filter gain drop in probe_rtt (0=disable)?");
1201 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1202 	    SYSCTL_CHILDREN(bbr_probertt),
1203 	    OID_AUTO, "cwnd", CTLFLAG_RW,
1204 	    &bbr_rtt_probe_cwndtarg, 4,
1205 	    "How many mss's are outstanding during probe-rtt");
1206 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1207 	    SYSCTL_CHILDREN(bbr_probertt),
1208 	    OID_AUTO, "int", CTLFLAG_RW,
1209 	    &bbr_rtt_probe_limit, 4000000,
1210 	    "If RTT has not shrank in this many micro-seconds enter probe-rtt");
1211 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1212 	    SYSCTL_CHILDREN(bbr_probertt),
1213 	    OID_AUTO, "mintime", CTLFLAG_RW,
1214 	    &bbr_rtt_probe_time, 200000,
1215 	    "How many microseconds in probe-rtt");
1216 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1217 	    SYSCTL_CHILDREN(bbr_probertt),
1218 	    OID_AUTO, "filter_len_sec", CTLFLAG_RW,
1219 	    &bbr_filter_len_sec, 6,
1220 	    "How long in seconds does the rttProp filter run?");
1221 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1222 	    SYSCTL_CHILDREN(bbr_probertt),
1223 	    OID_AUTO, "drain_rtt", CTLFLAG_RW,
1224 	    &bbr_drain_rtt, BBR_SRTT,
1225 	    "What is the drain rtt to use in probeRTT (rtt_prop=0, rtt_rack=1, rtt_pkt=2, rtt_srtt=3?");
1226 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1227 	    SYSCTL_CHILDREN(bbr_probertt),
1228 	    OID_AUTO, "can_force", CTLFLAG_RW,
1229 	    &bbr_can_force_probertt, 0,
1230 	    "If we keep setting new low rtt's but delay going in probe-rtt can we force in??");
1231 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1232 	    SYSCTL_CHILDREN(bbr_probertt),
1233 	    OID_AUTO, "enter_sets_force", CTLFLAG_RW,
1234 	    &bbr_probertt_sets_rtt, 0,
1235 	    "In NF mode, do we imitate google_mode and set the rttProp on entry to probe-rtt?");
1236 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1237 	    SYSCTL_CHILDREN(bbr_probertt),
1238 	    OID_AUTO, "can_adjust", CTLFLAG_RW,
1239 	    &bbr_can_adjust_probertt, 1,
1240 	    "Can we dynamically adjust the probe-rtt limits and times?");
1241 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1242 	    SYSCTL_CHILDREN(bbr_probertt),
1243 	    OID_AUTO, "is_ratio", CTLFLAG_RW,
1244 	    &bbr_is_ratio, 0,
1245 	    "is the limit to filter a ratio?");
1246 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1247 	    SYSCTL_CHILDREN(bbr_probertt),
1248 	    OID_AUTO, "use_cwnd", CTLFLAG_RW,
1249 	    &bbr_prtt_slam_cwnd, 0,
1250 	    "Should we set/recover cwnd?");
1251 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1252 	    SYSCTL_CHILDREN(bbr_probertt),
1253 	    OID_AUTO, "can_use_ts", CTLFLAG_RW,
1254 	    &bbr_can_use_ts_for_rtt, 1,
1255 	    "Can we use the ms timestamp if available for retransmistted rtt calculations?");
1256 
1257 	/* Pacing controls */
1258 	bbr_hptsi = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1259 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1260 	    OID_AUTO,
1261 	    "pacing",
1262 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1263 	    "");
1264 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1265 	    SYSCTL_CHILDREN(bbr_hptsi),
1266 	    OID_AUTO, "hw_pacing", CTLFLAG_RW,
1267 	    &bbr_allow_hdwr_pacing, 1,
1268 	    "Do we allow hardware pacing?");
1269 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1270 	    SYSCTL_CHILDREN(bbr_hptsi),
1271 	    OID_AUTO, "hw_pacing_limit", CTLFLAG_RW,
1272 	    &bbr_hardware_pacing_limit, 4000,
1273 	    "Do we have a limited number of connections for pacing chelsio (0=no limit)?");
1274 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1275 	    SYSCTL_CHILDREN(bbr_hptsi),
1276 	    OID_AUTO, "hw_pacing_adj", CTLFLAG_RW,
1277 	    &bbr_hdwr_pace_adjust, 2,
1278 	    "Multiplier to calculated tso size?");
1279 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1280 	    SYSCTL_CHILDREN(bbr_hptsi),
1281 	    OID_AUTO, "hw_pacing_floor", CTLFLAG_RW,
1282 	    &bbr_hdwr_pace_floor, 1,
1283 	    "Do we invoke the hardware pacing floor?");
1284 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1285 	    SYSCTL_CHILDREN(bbr_hptsi),
1286 	    OID_AUTO, "hw_pacing_delay_cnt", CTLFLAG_RW,
1287 	    &bbr_hdwr_pacing_delay_cnt, 10,
1288 	    "How many packets must be sent after hdwr pacing is enabled");
1289 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1290 	    SYSCTL_CHILDREN(bbr_hptsi),
1291 	    OID_AUTO, "bw_cross", CTLFLAG_RW,
1292 	    &bbr_cross_over, 3000000,
1293 	    "What is the point where we cross over to linux like TSO size set");
1294 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1295 	    SYSCTL_CHILDREN(bbr_hptsi),
1296 	    OID_AUTO, "seg_deltarg", CTLFLAG_RW,
1297 	    &bbr_hptsi_segments_delay_tar, 7000,
1298 	    "What is the worse case delay target for hptsi < 48Mbp connections");
1299 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1300 	    SYSCTL_CHILDREN(bbr_hptsi),
1301 	    OID_AUTO, "enet_oh", CTLFLAG_RW,
1302 	    &bbr_include_enet_oh, 0,
1303 	    "Do we include the ethernet overhead in calculating pacing delay?");
1304 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1305 	    SYSCTL_CHILDREN(bbr_hptsi),
1306 	    OID_AUTO, "ip_oh", CTLFLAG_RW,
1307 	    &bbr_include_ip_oh, 1,
1308 	    "Do we include the IP overhead in calculating pacing delay?");
1309 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1310 	    SYSCTL_CHILDREN(bbr_hptsi),
1311 	    OID_AUTO, "tcp_oh", CTLFLAG_RW,
1312 	    &bbr_include_tcp_oh, 0,
1313 	    "Do we include the TCP overhead in calculating pacing delay?");
1314 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1315 	    SYSCTL_CHILDREN(bbr_hptsi),
1316 	    OID_AUTO, "google_discount", CTLFLAG_RW,
1317 	    &bbr_google_discount, 10,
1318 	    "What is the default google discount percentage wise for pacing (11 = 1.1%%)?");
1319 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1320 	    SYSCTL_CHILDREN(bbr_hptsi),
1321 	    OID_AUTO, "all_get_min", CTLFLAG_RW,
1322 	    &bbr_all_get_min, 0,
1323 	    "If you are less than a MSS do you just get the min?");
1324 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1325 	    SYSCTL_CHILDREN(bbr_hptsi),
1326 	    OID_AUTO, "tso_min", CTLFLAG_RW,
1327 	    &bbr_hptsi_bytes_min, 1460,
1328 	    "For 0 -> 24Mbps what is floor number of segments for TSO");
1329 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1330 	    SYSCTL_CHILDREN(bbr_hptsi),
1331 	    OID_AUTO, "seg_tso_max", CTLFLAG_RW,
1332 	    &bbr_hptsi_segments_max, 6,
1333 	    "For 0 -> 24Mbps what is top number of segments for TSO");
1334 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1335 	    SYSCTL_CHILDREN(bbr_hptsi),
1336 	    OID_AUTO, "seg_floor", CTLFLAG_RW,
1337 	    &bbr_hptsi_segments_floor, 1,
1338 	    "Minimum TSO size we will fall too in segments");
1339 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1340 	    SYSCTL_CHILDREN(bbr_hptsi),
1341 	    OID_AUTO, "utter_max", CTLFLAG_RW,
1342 	    &bbr_hptsi_utter_max, 0,
1343 	    "The absolute maximum that any pacing (outside of hardware) can be");
1344 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1345 	    SYSCTL_CHILDREN(bbr_hptsi),
1346 	    OID_AUTO, "seg_divisor", CTLFLAG_RW,
1347 	    &bbr_hptsi_per_second, 100,
1348 	    "What is the divisor in our hptsi TSO calculation 512Mbps < X > 24Mbps ");
1349 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1350 	    SYSCTL_CHILDREN(bbr_hptsi),
1351 	    OID_AUTO, "srtt_mul", CTLFLAG_RW,
1352 	    &bbr_hptsi_max_mul, 1,
1353 	    "The multiplier for pace len max");
1354 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1355 	    SYSCTL_CHILDREN(bbr_hptsi),
1356 	    OID_AUTO, "srtt_div", CTLFLAG_RW,
1357 	    &bbr_hptsi_max_div, 2,
1358 	    "The divisor for pace len max");
1359 	/* Measurement controls */
1360 	bbr_measure = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1361 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1362 	    OID_AUTO,
1363 	    "measure",
1364 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1365 	    "Measurement controls");
1366 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1367 	    SYSCTL_CHILDREN(bbr_measure),
1368 	    OID_AUTO, "min_i_bw", CTLFLAG_RW,
1369 	    &bbr_initial_bw_bps, 62500,
1370 	    "Minimum initial b/w in bytes per second");
1371 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1372 	    SYSCTL_CHILDREN(bbr_measure),
1373 	    OID_AUTO, "no_sack_needed", CTLFLAG_RW,
1374 	    &bbr_sack_not_required, 0,
1375 	    "Do we allow bbr to run on connections not supporting SACK?");
1376 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1377 	    SYSCTL_CHILDREN(bbr_measure),
1378 	    OID_AUTO, "use_google", CTLFLAG_RW,
1379 	    &bbr_use_google_algo, 0,
1380 	    "Use has close to google V1.0 has possible?");
1381 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1382 	    SYSCTL_CHILDREN(bbr_measure),
1383 	    OID_AUTO, "ts_limiting", CTLFLAG_RW,
1384 	    &bbr_ts_limiting, 1,
1385 	    "Do we attempt to use the peers timestamp to limit b/w caculations?");
1386 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1387 	    SYSCTL_CHILDREN(bbr_measure),
1388 	    OID_AUTO, "ts_can_raise", CTLFLAG_RW,
1389 	    &bbr_ts_can_raise, 0,
1390 	    "Can we raise the b/w via timestamp b/w calculation?");
1391 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1392 	    SYSCTL_CHILDREN(bbr_measure),
1393 	    OID_AUTO, "ts_delta", CTLFLAG_RW,
1394 	    &bbr_min_usec_delta, 20000,
1395 	    "How long in usec between ts of our sends in ts validation code?");
1396 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1397 	    SYSCTL_CHILDREN(bbr_measure),
1398 	    OID_AUTO, "ts_peer_delta", CTLFLAG_RW,
1399 	    &bbr_min_peer_delta, 20,
1400 	    "What min numerical value should be between the peer deltas?");
1401 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1402 	    SYSCTL_CHILDREN(bbr_measure),
1403 	    OID_AUTO, "ts_delta_percent", CTLFLAG_RW,
1404 	    &bbr_delta_percent, 150,
1405 	    "What percentage (150 = 15.0) do we allow variance for?");
1406 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1407 	    SYSCTL_CHILDREN(bbr_measure),
1408 	    OID_AUTO, "min_measure_good_bw", CTLFLAG_RW,
1409 	    &bbr_min_measurements_req, 1,
1410 	    "What is the minimum measurment count we need before we switch to our b/w estimate");
1411 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1412 	    SYSCTL_CHILDREN(bbr_measure),
1413 	    OID_AUTO, "min_measure_before_pace", CTLFLAG_RW,
1414 	    &bbr_no_pacing_until, 4,
1415 	    "How many pkt-epoch's (0 is off) do we need before pacing is on?");
1416 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1417 	    SYSCTL_CHILDREN(bbr_measure),
1418 	    OID_AUTO, "quanta", CTLFLAG_RW,
1419 	    &bbr_quanta, 2,
1420 	    "Extra quanta to add when calculating the target (ID section 4.2.3.2).");
1421 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1422 	    SYSCTL_CHILDREN(bbr_measure),
1423 	    OID_AUTO, "noretran", CTLFLAG_RW,
1424 	    &bbr_no_retran, 0,
1425 	    "Should google mode not use retransmission measurements for the b/w estimation?");
1426 	/* State controls */
1427 	bbr_states = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1428 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1429 	    OID_AUTO,
1430 	    "states",
1431 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1432 	    "State controls");
1433 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1434 	    SYSCTL_CHILDREN(bbr_states),
1435 	    OID_AUTO, "idle_restart", CTLFLAG_RW,
1436 	    &bbr_uses_idle_restart, 0,
1437 	    "Do we use a new special idle_restart state to ramp back up quickly?");
1438 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1439 	    SYSCTL_CHILDREN(bbr_states),
1440 	    OID_AUTO, "idle_restart_threshold", CTLFLAG_RW,
1441 	    &bbr_idle_restart_threshold, 100000,
1442 	    "How long must we be idle before we restart??");
1443 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1444 	    SYSCTL_CHILDREN(bbr_states),
1445 	    OID_AUTO, "use_pkt_epoch", CTLFLAG_RW,
1446 	    &bbr_state_is_pkt_epoch, 0,
1447 	    "Do we use a pkt-epoch for substate if 0 rttProp?");
1448 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1449 	    SYSCTL_CHILDREN(bbr_states),
1450 	    OID_AUTO, "startup_rtt_gain", CTLFLAG_RW,
1451 	    &bbr_rtt_gain_thresh, 0,
1452 	    "What increase in RTT triggers us to stop ignoring no-loss and possibly exit startup?");
1453 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1454 	    SYSCTL_CHILDREN(bbr_states),
1455 	    OID_AUTO, "drain_floor", CTLFLAG_RW,
1456 	    &bbr_drain_floor, 88,
1457 	    "What is the lowest we can drain (pg) too?");
1458 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1459 	    SYSCTL_CHILDREN(bbr_states),
1460 	    OID_AUTO, "drain_2_target", CTLFLAG_RW,
1461 	    &bbr_state_drain_2_tar, 1,
1462 	    "Do we drain to target in drain substate?");
1463 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1464 	    SYSCTL_CHILDREN(bbr_states),
1465 	    OID_AUTO, "gain_2_target", CTLFLAG_RW,
1466 	    &bbr_gain_to_target, 1,
1467 	    "Does probe bw gain to target??");
1468 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1469 	    SYSCTL_CHILDREN(bbr_states),
1470 	    OID_AUTO, "gain_extra_time", CTLFLAG_RW,
1471 	    &bbr_gain_gets_extra_too, 1,
1472 	    "Does probe bw gain get the extra time too?");
1473 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1474 	    SYSCTL_CHILDREN(bbr_states),
1475 	    OID_AUTO, "ld_div", CTLFLAG_RW,
1476 	    &bbr_drain_drop_div, 5,
1477 	    "Long drain drop divider?");
1478 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1479 	    SYSCTL_CHILDREN(bbr_states),
1480 	    OID_AUTO, "ld_mul", CTLFLAG_RW,
1481 	    &bbr_drain_drop_mul, 4,
1482 	    "Long drain drop multiplier?");
1483 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1484 	    SYSCTL_CHILDREN(bbr_states),
1485 	    OID_AUTO, "rand_ot_disc", CTLFLAG_RW,
1486 	    &bbr_rand_ot, 50,
1487 	    "Random discount of the ot?");
1488 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1489 	    SYSCTL_CHILDREN(bbr_states),
1490 	    OID_AUTO, "dr_filter_life", CTLFLAG_RW,
1491 	    &bbr_num_pktepo_for_del_limit, BBR_NUM_RTTS_FOR_DEL_LIMIT,
1492 	    "How many packet-epochs does the b/w delivery rate last?");
1493 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1494 	    SYSCTL_CHILDREN(bbr_states),
1495 	    OID_AUTO, "subdrain_applimited", CTLFLAG_RW,
1496 	    &bbr_sub_drain_app_limit, 0,
1497 	    "Does our sub-state drain invoke app limited if its long?");
1498 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1499 	    SYSCTL_CHILDREN(bbr_states),
1500 	    OID_AUTO, "use_cwnd_subdrain", CTLFLAG_RW,
1501 	    &bbr_sub_drain_slam_cwnd, 0,
1502 	    "Should we set/recover cwnd for sub-state drain?");
1503 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1504 	    SYSCTL_CHILDREN(bbr_states),
1505 	    OID_AUTO, "use_cwnd_maindrain", CTLFLAG_RW,
1506 	    &bbr_slam_cwnd_in_main_drain, 0,
1507 	    "Should we set/recover cwnd for main-state drain?");
1508 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1509 	    SYSCTL_CHILDREN(bbr_states),
1510 	    OID_AUTO, "google_gets_earlyout", CTLFLAG_RW,
1511 	    &google_allow_early_out, 1,
1512 	    "Should we allow google probe-bw/drain to exit early at flight target?");
1513 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1514 	    SYSCTL_CHILDREN(bbr_states),
1515 	    OID_AUTO, "google_exit_loss", CTLFLAG_RW,
1516 	    &google_consider_lost, 1,
1517 	    "Should we have losses exit gain of probebw in google mode??");
1518 	/* Startup controls */
1519 	bbr_startup = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1520 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1521 	    OID_AUTO,
1522 	    "startup",
1523 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1524 	    "Startup controls");
1525 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1526 	    SYSCTL_CHILDREN(bbr_startup),
1527 	    OID_AUTO, "cheat_iwnd", CTLFLAG_RW,
1528 	    &bbr_sends_full_iwnd, 1,
1529 	    "Do we not pace but burst out initial windows has our TSO size?");
1530 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1531 	    SYSCTL_CHILDREN(bbr_startup),
1532 	    OID_AUTO, "loss_threshold", CTLFLAG_RW,
1533 	    &bbr_startup_loss_thresh, 2000,
1534 	    "In startup what is the loss threshold in a pe that will exit us from startup?");
1535 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1536 	    SYSCTL_CHILDREN(bbr_startup),
1537 	    OID_AUTO, "use_lowerpg", CTLFLAG_RW,
1538 	    &bbr_use_lower_gain_in_startup, 1,
1539 	    "Should we use a lower hptsi gain if we see loss in startup?");
1540 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1541 	    SYSCTL_CHILDREN(bbr_startup),
1542 	    OID_AUTO, "gain", CTLFLAG_RW,
1543 	    &bbr_start_exit, 25,
1544 	    "What gain percent do we need to see to stay in startup??");
1545 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1546 	    SYSCTL_CHILDREN(bbr_startup),
1547 	    OID_AUTO, "low_gain", CTLFLAG_RW,
1548 	    &bbr_low_start_exit, 15,
1549 	    "What gain percent do we need to see to stay in the lower gain startup??");
1550 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1551 	    SYSCTL_CHILDREN(bbr_startup),
1552 	    OID_AUTO, "loss_exit", CTLFLAG_RW,
1553 	    &bbr_exit_startup_at_loss, 1,
1554 	    "Should we exit startup at loss in an epoch if we are not gaining?");
1555 	/* CWND controls */
1556 	bbr_cwnd = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1557 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1558 	    OID_AUTO,
1559 	    "cwnd",
1560 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1561 	    "Cwnd controls");
1562 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1563 	    SYSCTL_CHILDREN(bbr_cwnd),
1564 	    OID_AUTO, "tar_rtt", CTLFLAG_RW,
1565 	    &bbr_cwndtarget_rtt_touse, 0,
1566 	    "Target cwnd rtt measurment to use (0=rtt_prop, 1=rtt_rack, 2=pkt_rtt, 3=srtt)?");
1567 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1568 	    SYSCTL_CHILDREN(bbr_cwnd),
1569 	    OID_AUTO, "may_shrink", CTLFLAG_RW,
1570 	    &bbr_cwnd_may_shrink, 0,
1571 	    "Can the cwnd shrink if it would grow to more than the target?");
1572 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1573 	    SYSCTL_CHILDREN(bbr_cwnd),
1574 	    OID_AUTO, "max_target_limit", CTLFLAG_RW,
1575 	    &bbr_target_cwnd_mult_limit, 8,
1576 	    "Do we limit the cwnd to some multiple of the cwnd target if cwnd can't shrink 0=no?");
1577 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1578 	    SYSCTL_CHILDREN(bbr_cwnd),
1579 	    OID_AUTO, "highspeed_min", CTLFLAG_RW,
1580 	    &bbr_cwnd_min_val_hs, BBR_HIGHSPEED_NUM_MSS,
1581 	    "What is the high-speed min cwnd (rttProp under 1ms)");
1582 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1583 	    SYSCTL_CHILDREN(bbr_cwnd),
1584 	    OID_AUTO, "lowspeed_min", CTLFLAG_RW,
1585 	    &bbr_cwnd_min_val, BBR_PROBERTT_NUM_MSS,
1586 	    "What is the min cwnd (rttProp > 1ms)");
1587 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1588 	    SYSCTL_CHILDREN(bbr_cwnd),
1589 	    OID_AUTO, "initwin", CTLFLAG_RW,
1590 	    &bbr_def_init_win, 10,
1591 	    "What is the BBR initial window, if 0 use tcp version");
1592 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1593 	    SYSCTL_CHILDREN(bbr_cwnd),
1594 	    OID_AUTO, "do_loss_red", CTLFLAG_RW,
1595 	    &bbr_do_red, 600,
1596 	    "Do we reduce the b/w at exit from recovery based on ratio of prop/srtt (800=80.0, 0=off)?");
1597 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1598 	    SYSCTL_CHILDREN(bbr_cwnd),
1599 	    OID_AUTO, "red_scale", CTLFLAG_RW,
1600 	    &bbr_red_scale, 20000,
1601 	    "What RTT do we scale with?");
1602 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1603 	    SYSCTL_CHILDREN(bbr_cwnd),
1604 	    OID_AUTO, "red_growslow", CTLFLAG_RW,
1605 	    &bbr_red_growth_restrict, 1,
1606 	    "Do we restrict cwnd growth for whats in flight?");
1607 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1608 	    SYSCTL_CHILDREN(bbr_cwnd),
1609 	    OID_AUTO, "red_div", CTLFLAG_RW,
1610 	    &bbr_red_div, 2,
1611 	    "If we reduce whats the divisor?");
1612 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1613 	    SYSCTL_CHILDREN(bbr_cwnd),
1614 	    OID_AUTO, "red_mul", CTLFLAG_RW,
1615 	    &bbr_red_mul, 1,
1616 	    "If we reduce whats the mulitiplier?");
1617 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1618 	    SYSCTL_CHILDREN(bbr_cwnd),
1619 	    OID_AUTO, "target_is_unit", CTLFLAG_RW,
1620 	    &bbr_target_is_bbunit, 0,
1621 	    "Is the state target the pacing_gain or BBR_UNIT?");
1622 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1623 	    SYSCTL_CHILDREN(bbr_cwnd),
1624 	    OID_AUTO, "drop_limit", CTLFLAG_RW,
1625 	    &bbr_drop_limit, 0,
1626 	    "Number of segments limit for drop (0=use min_cwnd w/flight)?");
1627 
1628         /* Timeout controls */
1629 	bbr_timeout = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1630 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1631 	    OID_AUTO,
1632 	    "timeout",
1633 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1634 	    "Time out controls");
1635 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1636 	    SYSCTL_CHILDREN(bbr_timeout),
1637 	    OID_AUTO, "delack", CTLFLAG_RW,
1638 	    &bbr_delack_time, 100000,
1639 	    "BBR's delayed ack time");
1640 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1641 	    SYSCTL_CHILDREN(bbr_timeout),
1642 	    OID_AUTO, "tlp_uses", CTLFLAG_RW,
1643 	    &bbr_tlp_type_to_use, 3,
1644 	    "RTT that TLP uses in its calculations, 0=rttProp, 1=Rack_rtt, 2=pkt_rtt and 3=srtt");
1645 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1646 	    SYSCTL_CHILDREN(bbr_timeout),
1647 	    OID_AUTO, "persmin", CTLFLAG_RW,
1648 	    &bbr_persist_min, 250000,
1649 	    "What is the minimum time in microseconds between persists");
1650 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1651 	    SYSCTL_CHILDREN(bbr_timeout),
1652 	    OID_AUTO, "persmax", CTLFLAG_RW,
1653 	    &bbr_persist_max, 1000000,
1654 	    "What is the largest delay in microseconds between persists");
1655 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1656 	    SYSCTL_CHILDREN(bbr_timeout),
1657 	    OID_AUTO, "tlp_minto", CTLFLAG_RW,
1658 	    &bbr_tlp_min, 10000,
1659 	    "TLP Min timeout in usecs");
1660 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1661 	    SYSCTL_CHILDREN(bbr_timeout),
1662 	    OID_AUTO, "tlp_dack_time", CTLFLAG_RW,
1663 	    &bbr_delayed_ack_time, 200000,
1664 	    "TLP delayed ack compensation value");
1665 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1666 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1667 	    OID_AUTO, "minrto", CTLFLAG_RW,
1668 	    &bbr_rto_min_ms, 30,
1669 	    "Minimum RTO in ms");
1670 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1671 	    SYSCTL_CHILDREN(bbr_timeout),
1672 	    OID_AUTO, "maxrto", CTLFLAG_RW,
1673 	    &bbr_rto_max_sec, 4,
1674 	    "Maxiumum RTO in seconds -- should be at least as large as min_rto");
1675 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1676 	    SYSCTL_CHILDREN(bbr_timeout),
1677 	    OID_AUTO, "tlp_retry", CTLFLAG_RW,
1678 	    &bbr_tlp_max_resend, 2,
1679 	    "How many times does TLP retry a single segment or multiple with no ACK");
1680 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1681 	    SYSCTL_CHILDREN(bbr_timeout),
1682 	    OID_AUTO, "minto", CTLFLAG_RW,
1683 	    &bbr_min_to, 1000,
1684 	    "Minimum rack timeout in useconds");
1685 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1686 	    SYSCTL_CHILDREN(bbr_timeout),
1687 	    OID_AUTO, "pktdelay", CTLFLAG_RW,
1688 	    &bbr_pkt_delay, 1000,
1689 	    "Extra RACK time (in useconds) besides reordering thresh");
1690 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1691 	    SYSCTL_CHILDREN(bbr_timeout),
1692 	    OID_AUTO, "incr_tmrs", CTLFLAG_RW,
1693 	    &bbr_incr_timers, 1,
1694 	    "Increase the RXT/TLP timer by the pacing time used?");
1695 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1696 	    SYSCTL_CHILDREN(bbr_timeout),
1697 	    OID_AUTO, "rxtmark_sackpassed", CTLFLAG_RW,
1698 	    &bbr_marks_rxt_sack_passed, 0,
1699 	    "Mark sack passed on all those not ack'd when a RXT hits?");
1700 	/* Policer controls */
1701 	bbr_policer = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1702 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1703 	    OID_AUTO,
1704 	    "policer",
1705 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1706 	    "Policer controls");
1707 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1708 	    SYSCTL_CHILDREN(bbr_policer),
1709 	    OID_AUTO, "detect_enable", CTLFLAG_RW,
1710 	    &bbr_policer_detection_enabled, 1,
1711 	    "Is policer detection enabled??");
1712 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1713 	    SYSCTL_CHILDREN(bbr_policer),
1714 	    OID_AUTO, "min_pes", CTLFLAG_RW,
1715 	    &bbr_lt_intvl_min_rtts, 4,
1716 	    "Minimum number of PE's?");
1717 	SYSCTL_ADD_U64(&bbr_sysctl_ctx,
1718 	    SYSCTL_CHILDREN(bbr_policer),
1719 	    OID_AUTO, "bwdiff", CTLFLAG_RW,
1720 	    &bbr_lt_bw_diff, (4000/8),
1721 	    "Minimal bw diff?");
1722 	SYSCTL_ADD_U64(&bbr_sysctl_ctx,
1723 	    SYSCTL_CHILDREN(bbr_policer),
1724 	    OID_AUTO, "bwratio", CTLFLAG_RW,
1725 	    &bbr_lt_bw_ratio, 8,
1726 	    "Minimal bw diff?");
1727 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1728 	    SYSCTL_CHILDREN(bbr_policer),
1729 	    OID_AUTO, "from_rack_rxt", CTLFLAG_RW,
1730 	    &bbr_policer_call_from_rack_to, 0,
1731 	    "Do we call the policer detection code from a rack-timeout?");
1732 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1733 	    SYSCTL_CHILDREN(bbr_policer),
1734 	    OID_AUTO, "false_postive", CTLFLAG_RW,
1735 	    &bbr_lt_intvl_fp, 0,
1736 	    "What packet epoch do we do false-postive detection at (0=no)?");
1737 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1738 	    SYSCTL_CHILDREN(bbr_policer),
1739 	    OID_AUTO, "loss_thresh", CTLFLAG_RW,
1740 	    &bbr_lt_loss_thresh, 196,
1741 	    "Loss threshold 196 = 19.6%?");
1742 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1743 	    SYSCTL_CHILDREN(bbr_policer),
1744 	    OID_AUTO, "false_postive_thresh", CTLFLAG_RW,
1745 	    &bbr_lt_fd_thresh, 100,
1746 	    "What percentage is the false detection threshold (150=15.0)?");
1747 	/* All the rest */
1748 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1749 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1750 	    OID_AUTO, "cheat_rxt", CTLFLAG_RW,
1751 	    &bbr_use_rack_resend_cheat, 0,
1752 	    "Do we burst 1ms between sends on retransmissions (like rack)?");
1753 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1754 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1755 	    OID_AUTO, "error_paceout", CTLFLAG_RW,
1756 	    &bbr_error_base_paceout, 10000,
1757 	    "When we hit an error what is the min to pace out in usec's?");
1758 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1759 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1760 	    OID_AUTO, "kill_paceout", CTLFLAG_RW,
1761 	    &bbr_max_net_error_cnt, 10,
1762 	    "When we hit this many errors in a row, kill the session?");
1763 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1764 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1765 	    OID_AUTO, "data_after_close", CTLFLAG_RW,
1766 	    &bbr_ignore_data_after_close, 1,
1767 	    "Do we hold off sending a RST until all pending data is ack'd");
1768 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1769 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1770 	    OID_AUTO, "resend_use_tso", CTLFLAG_RW,
1771 	    &bbr_resends_use_tso, 0,
1772 	    "Can resends use TSO?");
1773 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1774 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1775 	    OID_AUTO, "sblklimit", CTLFLAG_RW,
1776 	    &bbr_sack_block_limit, 128,
1777 	    "When do we start ignoring small sack blocks");
1778 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1779 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1780 	    OID_AUTO, "bb_verbose", CTLFLAG_RW,
1781 	    &bbr_verbose_logging, 0,
1782 	    "Should BBR black box logging be verbose");
1783 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1784 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1785 	    OID_AUTO, "reorder_thresh", CTLFLAG_RW,
1786 	    &bbr_reorder_thresh, 2,
1787 	    "What factor for rack will be added when seeing reordering (shift right)");
1788 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1789 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1790 	    OID_AUTO, "reorder_fade", CTLFLAG_RW,
1791 	    &bbr_reorder_fade, 0,
1792 	    "Does reorder detection fade, if so how many ms (0 means never)");
1793 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1794 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1795 	    OID_AUTO, "rtt_tlp_thresh", CTLFLAG_RW,
1796 	    &bbr_tlp_thresh, 1,
1797 	    "what divisor for TLP rtt/retran will be added (1=rtt, 2=1/2 rtt etc)");
1798 	/* Stats and counters */
1799 	/* The pacing counters for hdwr/software can't be in the array */
1800 	bbr_nohdwr_pacing_enobuf = counter_u64_alloc(M_WAITOK);
1801 	bbr_hdwr_pacing_enobuf = counter_u64_alloc(M_WAITOK);
1802 	SYSCTL_ADD_COUNTER_U64(&bbr_sysctl_ctx,
1803 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1804 	    OID_AUTO, "enob_hdwr_pacing", CTLFLAG_RD,
1805 	    &bbr_hdwr_pacing_enobuf,
1806 	    "Total number of enobufs for hardware paced flows");
1807 	SYSCTL_ADD_COUNTER_U64(&bbr_sysctl_ctx,
1808 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1809 	    OID_AUTO, "enob_no_hdwr_pacing", CTLFLAG_RD,
1810 	    &bbr_nohdwr_pacing_enobuf,
1811 	    "Total number of enobufs for non-hardware paced flows");
1812 
1813 
1814 	bbr_flows_whdwr_pacing = counter_u64_alloc(M_WAITOK);
1815 	SYSCTL_ADD_COUNTER_U64(&bbr_sysctl_ctx,
1816 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1817 	    OID_AUTO, "hdwr_pacing", CTLFLAG_RD,
1818 	    &bbr_flows_whdwr_pacing,
1819 	    "Total number of hardware paced flows");
1820 	bbr_flows_nohdwr_pacing = counter_u64_alloc(M_WAITOK);
1821 	SYSCTL_ADD_COUNTER_U64(&bbr_sysctl_ctx,
1822 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1823 	    OID_AUTO, "software_pacing", CTLFLAG_RD,
1824 	    &bbr_flows_nohdwr_pacing,
1825 	    "Total number of software paced flows");
1826 	COUNTER_ARRAY_ALLOC(bbr_stat_arry, BBR_STAT_SIZE, M_WAITOK);
1827 	SYSCTL_ADD_COUNTER_U64_ARRAY(&bbr_sysctl_ctx, SYSCTL_CHILDREN(bbr_sysctl_root),
1828 	    OID_AUTO, "stats", CTLFLAG_RD,
1829 	    bbr_stat_arry, BBR_STAT_SIZE, "BBR Stats");
1830 	COUNTER_ARRAY_ALLOC(bbr_opts_arry, BBR_OPTS_SIZE, M_WAITOK);
1831 	SYSCTL_ADD_COUNTER_U64_ARRAY(&bbr_sysctl_ctx, SYSCTL_CHILDREN(bbr_sysctl_root),
1832 	    OID_AUTO, "opts", CTLFLAG_RD,
1833 	    bbr_opts_arry, BBR_OPTS_SIZE, "BBR Option Stats");
1834 	COUNTER_ARRAY_ALLOC(bbr_state_lost, BBR_MAX_STAT, M_WAITOK);
1835 	SYSCTL_ADD_COUNTER_U64_ARRAY(&bbr_sysctl_ctx, SYSCTL_CHILDREN(bbr_sysctl_root),
1836 	    OID_AUTO, "lost", CTLFLAG_RD,
1837 	    bbr_state_lost, BBR_MAX_STAT, "Stats of when losses occur");
1838 	COUNTER_ARRAY_ALLOC(bbr_state_resend, BBR_MAX_STAT, M_WAITOK);
1839 	SYSCTL_ADD_COUNTER_U64_ARRAY(&bbr_sysctl_ctx, SYSCTL_CHILDREN(bbr_sysctl_root),
1840 	    OID_AUTO, "stateresend", CTLFLAG_RD,
1841 	    bbr_state_resend, BBR_MAX_STAT, "Stats of what states resend");
1842 	COUNTER_ARRAY_ALLOC(bbr_state_time, BBR_MAX_STAT, M_WAITOK);
1843 	SYSCTL_ADD_COUNTER_U64_ARRAY(&bbr_sysctl_ctx, SYSCTL_CHILDREN(bbr_sysctl_root),
1844 	    OID_AUTO, "statetime", CTLFLAG_RD,
1845 	    bbr_state_time, BBR_MAX_STAT, "Stats of time spent in the states");
1846 	COUNTER_ARRAY_ALLOC(bbr_out_size, TCP_MSS_ACCT_SIZE, M_WAITOK);
1847 	SYSCTL_ADD_COUNTER_U64_ARRAY(&bbr_sysctl_ctx, SYSCTL_CHILDREN(bbr_sysctl_root),
1848 	    OID_AUTO, "outsize", CTLFLAG_RD,
1849 	    bbr_out_size, TCP_MSS_ACCT_SIZE, "Size of output calls");
1850 	SYSCTL_ADD_PROC(&bbr_sysctl_ctx,
1851 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1852 	    OID_AUTO, "clrlost", CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE,
1853 	    &bbr_clear_lost, 0, sysctl_bbr_clear_lost, "IU", "Clear lost counters");
1854 }
1855 
1856 static inline int32_t
1857 bbr_progress_timeout_check(struct tcp_bbr *bbr)
1858 {
1859 	if (bbr->rc_tp->t_maxunacktime && bbr->rc_tp->t_acktime &&
1860 	    TSTMP_GT(ticks, bbr->rc_tp->t_acktime)) {
1861 		if ((((uint32_t)ticks - bbr->rc_tp->t_acktime)) >= bbr->rc_tp->t_maxunacktime) {
1862 			/*
1863 			 * There is an assumption here that the caller will
1864 			 * drop the connection, so we increment the
1865 			 * statistics.
1866 			 */
1867 			bbr_log_progress_event(bbr, bbr->rc_tp, ticks, PROGRESS_DROP, __LINE__);
1868 			BBR_STAT_INC(bbr_progress_drops);
1869 #ifdef NETFLIX_STATS
1870 			KMOD_TCPSTAT_INC(tcps_progdrops);
1871 #endif
1872 			return (1);
1873 		}
1874 	}
1875 	return (0);
1876 }
1877 
1878 static void
1879 bbr_counter_destroy(void)
1880 {
1881 	COUNTER_ARRAY_FREE(bbr_stat_arry, BBR_STAT_SIZE);
1882 	COUNTER_ARRAY_FREE(bbr_opts_arry, BBR_OPTS_SIZE);
1883 	COUNTER_ARRAY_FREE(bbr_out_size, TCP_MSS_ACCT_SIZE);
1884 	COUNTER_ARRAY_FREE(bbr_state_lost, BBR_MAX_STAT);
1885 	COUNTER_ARRAY_FREE(bbr_state_time, BBR_MAX_STAT);
1886 	COUNTER_ARRAY_FREE(bbr_state_resend, BBR_MAX_STAT);
1887 	counter_u64_free(bbr_flows_whdwr_pacing);
1888 	counter_u64_free(bbr_flows_nohdwr_pacing);
1889 
1890 }
1891 
1892 static __inline void
1893 bbr_fill_in_logging_data(struct tcp_bbr *bbr, struct tcp_log_bbr *l, uint32_t cts)
1894 {
1895 	memset(l, 0, sizeof(union tcp_log_stackspecific));
1896 	l->cur_del_rate = bbr->r_ctl.rc_bbr_cur_del_rate;
1897 	l->delRate = get_filter_value(&bbr->r_ctl.rc_delrate);
1898 	l->rttProp = get_filter_value_small(&bbr->r_ctl.rc_rttprop);
1899 	l->bw_inuse = bbr_get_bw(bbr);
1900 	l->inflight = ctf_flight_size(bbr->rc_tp,
1901 			  (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
1902 	l->applimited = bbr->r_ctl.r_app_limited_until;
1903 	l->delivered = bbr->r_ctl.rc_delivered;
1904 	l->timeStamp = cts;
1905 	l->lost = bbr->r_ctl.rc_lost;
1906 	l->bbr_state = bbr->rc_bbr_state;
1907 	l->bbr_substate = bbr_state_val(bbr);
1908 	l->epoch = bbr->r_ctl.rc_rtt_epoch;
1909 	l->lt_epoch = bbr->r_ctl.rc_lt_epoch;
1910 	l->pacing_gain = bbr->r_ctl.rc_bbr_hptsi_gain;
1911 	l->cwnd_gain = bbr->r_ctl.rc_bbr_cwnd_gain;
1912 	l->inhpts = bbr->rc_inp->inp_in_hpts;
1913 	l->ininput = bbr->rc_inp->inp_in_input;
1914 	l->use_lt_bw = bbr->rc_lt_use_bw;
1915 	l->pkts_out = bbr->r_ctl.rc_flight_at_input;
1916 	l->pkt_epoch = bbr->r_ctl.rc_pkt_epoch;
1917 }
1918 
1919 static void
1920 bbr_log_type_bw_reduce(struct tcp_bbr *bbr, int reason)
1921 {
1922 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1923 		union tcp_log_stackspecific log;
1924 
1925 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
1926 		log.u_bbr.flex1 = 0;
1927 		log.u_bbr.flex2 = 0;
1928 		log.u_bbr.flex5 = 0;
1929 		log.u_bbr.flex3 = 0;
1930 		log.u_bbr.flex4 = bbr->r_ctl.rc_pkt_epoch_loss_rate;
1931 		log.u_bbr.flex7 = reason;
1932 		log.u_bbr.flex6 = bbr->r_ctl.rc_bbr_enters_probertt;
1933 		log.u_bbr.flex8 = 0;
1934 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
1935 		    &bbr->rc_inp->inp_socket->so_rcv,
1936 		    &bbr->rc_inp->inp_socket->so_snd,
1937 		    BBR_LOG_BW_RED_EV, 0,
1938 		    0, &log, false, &bbr->rc_tv);
1939 	}
1940 }
1941 
1942 static void
1943 bbr_log_type_rwnd_collapse(struct tcp_bbr *bbr, int seq, int mode, uint32_t count)
1944 {
1945 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1946 		union tcp_log_stackspecific log;
1947 
1948 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
1949 		log.u_bbr.flex1 = seq;
1950 		log.u_bbr.flex2 = count;
1951 		log.u_bbr.flex8 = mode;
1952 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
1953 		    &bbr->rc_inp->inp_socket->so_rcv,
1954 		    &bbr->rc_inp->inp_socket->so_snd,
1955 		    BBR_LOG_LOWGAIN, 0,
1956 		    0, &log, false, &bbr->rc_tv);
1957 	}
1958 }
1959 
1960 
1961 
1962 static void
1963 bbr_log_type_just_return(struct tcp_bbr *bbr, uint32_t cts, uint32_t tlen, uint8_t hpts_calling,
1964     uint8_t reason, uint32_t p_maxseg, int len)
1965 {
1966 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1967 		union tcp_log_stackspecific log;
1968 
1969 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
1970 		log.u_bbr.flex1 = p_maxseg;
1971 		log.u_bbr.flex2 = bbr->r_ctl.rc_hpts_flags;
1972 		log.u_bbr.flex3 = bbr->r_ctl.rc_timer_exp;
1973 		log.u_bbr.flex4 = reason;
1974 		log.u_bbr.flex5 = bbr->rc_in_persist;
1975 		log.u_bbr.flex6 = bbr->r_ctl.rc_last_delay_val;
1976 		log.u_bbr.flex7 = p_maxseg;
1977 		log.u_bbr.flex8 = bbr->rc_in_persist;
1978 		log.u_bbr.pkts_out = 0;
1979 		log.u_bbr.applimited = len;
1980 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
1981 		    &bbr->rc_inp->inp_socket->so_rcv,
1982 		    &bbr->rc_inp->inp_socket->so_snd,
1983 		    BBR_LOG_JUSTRET, 0,
1984 		    tlen, &log, false, &bbr->rc_tv);
1985 	}
1986 }
1987 
1988 
1989 static void
1990 bbr_log_type_enter_rec(struct tcp_bbr *bbr, uint32_t seq)
1991 {
1992 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1993 		union tcp_log_stackspecific log;
1994 
1995 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
1996 		log.u_bbr.flex1 = seq;
1997 		log.u_bbr.flex2 = bbr->r_ctl.rc_cwnd_on_ent;
1998 		log.u_bbr.flex3 = bbr->r_ctl.rc_recovery_start;
1999 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2000 		    &bbr->rc_inp->inp_socket->so_rcv,
2001 		    &bbr->rc_inp->inp_socket->so_snd,
2002 		    BBR_LOG_ENTREC, 0,
2003 		    0, &log, false, &bbr->rc_tv);
2004 	}
2005 }
2006 
2007 static void
2008 bbr_log_msgsize_fail(struct tcp_bbr *bbr, struct tcpcb *tp, uint32_t len, uint32_t maxseg, uint32_t mtu, int32_t csum_flags, int32_t tso, uint32_t cts)
2009 {
2010 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
2011 		union tcp_log_stackspecific log;
2012 
2013 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2014 		log.u_bbr.flex1 = tso;
2015 		log.u_bbr.flex2 = maxseg;
2016 		log.u_bbr.flex3 = mtu;
2017 		log.u_bbr.flex4 = csum_flags;
2018 		TCP_LOG_EVENTP(tp, NULL,
2019 		    &bbr->rc_inp->inp_socket->so_rcv,
2020 		    &bbr->rc_inp->inp_socket->so_snd,
2021 		    BBR_LOG_MSGSIZE, 0,
2022 		    0, &log, false, &bbr->rc_tv);
2023 	}
2024 }
2025 
2026 static void
2027 bbr_log_flowend(struct tcp_bbr *bbr)
2028 {
2029 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2030 		union tcp_log_stackspecific log;
2031 		struct sockbuf *r, *s;
2032 		struct timeval tv;
2033 
2034 		if (bbr->rc_inp->inp_socket) {
2035 			r = &bbr->rc_inp->inp_socket->so_rcv;
2036 			s = &bbr->rc_inp->inp_socket->so_snd;
2037 		} else {
2038 			r = s = NULL;
2039 		}
2040 		bbr_fill_in_logging_data(bbr, &log.u_bbr, tcp_get_usecs(&tv));
2041 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2042 		    r, s,
2043 		    TCP_LOG_FLOWEND, 0,
2044 		    0, &log, false, &tv);
2045 	}
2046 }
2047 
2048 static void
2049 bbr_log_pkt_epoch(struct tcp_bbr *bbr, uint32_t cts, uint32_t line,
2050     uint32_t lost, uint32_t del)
2051 {
2052 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2053 		union tcp_log_stackspecific log;
2054 
2055 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2056 		log.u_bbr.flex1 = lost;
2057 		log.u_bbr.flex2 = del;
2058 		log.u_bbr.flex3 = bbr->r_ctl.rc_bbr_lastbtlbw;
2059 		log.u_bbr.flex4 = bbr->r_ctl.rc_pkt_epoch_rtt;
2060 		log.u_bbr.flex5 = bbr->r_ctl.rc_bbr_last_startup_epoch;
2061 		log.u_bbr.flex6 = bbr->r_ctl.rc_lost_at_startup;
2062 		log.u_bbr.flex7 = line;
2063 		log.u_bbr.flex8 = 0;
2064 		log.u_bbr.inflight = bbr->r_ctl.r_measurement_count;
2065 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2066 		    &bbr->rc_inp->inp_socket->so_rcv,
2067 		    &bbr->rc_inp->inp_socket->so_snd,
2068 		    BBR_LOG_PKT_EPOCH, 0,
2069 		    0, &log, false, &bbr->rc_tv);
2070 	}
2071 }
2072 
2073 static void
2074 bbr_log_time_epoch(struct tcp_bbr *bbr, uint32_t cts, uint32_t line, uint32_t epoch_time)
2075 {
2076 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2077 		union tcp_log_stackspecific log;
2078 
2079 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2080 		log.u_bbr.flex1 = bbr->r_ctl.rc_lost;
2081 		log.u_bbr.flex2 = bbr->rc_inp->inp_socket->so_snd.sb_lowat;
2082 		log.u_bbr.flex3 = bbr->rc_inp->inp_socket->so_snd.sb_hiwat;
2083 		log.u_bbr.flex7 = line;
2084 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2085 		    &bbr->rc_inp->inp_socket->so_rcv,
2086 		    &bbr->rc_inp->inp_socket->so_snd,
2087 		    BBR_LOG_TIME_EPOCH, 0,
2088 		    0, &log, false, &bbr->rc_tv);
2089 	}
2090 }
2091 
2092 static void
2093 bbr_log_set_of_state_target(struct tcp_bbr *bbr, uint32_t new_tar, int line, int meth)
2094 {
2095 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2096 		union tcp_log_stackspecific log;
2097 
2098 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2099 		log.u_bbr.flex1 = bbr->r_ctl.rc_target_at_state;
2100 		log.u_bbr.flex2 = new_tar;
2101 		log.u_bbr.flex3 = line;
2102 		log.u_bbr.flex4 = bbr->r_ctl.rc_pace_max_segs;
2103 		log.u_bbr.flex5 = bbr_quanta;
2104 		log.u_bbr.flex6 = bbr->r_ctl.rc_pace_min_segs;
2105 		log.u_bbr.flex7 = bbr->rc_last_options;
2106 		log.u_bbr.flex8 = meth;
2107 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2108 		    &bbr->rc_inp->inp_socket->so_rcv,
2109 		    &bbr->rc_inp->inp_socket->so_snd,
2110 		    BBR_LOG_STATE_TARGET, 0,
2111 		    0, &log, false, &bbr->rc_tv);
2112 	}
2113 
2114 }
2115 
2116 static void
2117 bbr_log_type_statechange(struct tcp_bbr *bbr, uint32_t cts, int32_t line)
2118 {
2119 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2120 		union tcp_log_stackspecific log;
2121 
2122 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2123 		log.u_bbr.flex1 = line;
2124 		log.u_bbr.flex2 = bbr->r_ctl.rc_rtt_shrinks;
2125 		log.u_bbr.flex3 = bbr->r_ctl.rc_probertt_int;
2126 		if (bbr_state_is_pkt_epoch)
2127 			log.u_bbr.flex4 = bbr_get_rtt(bbr, BBR_RTT_PKTRTT);
2128 		else
2129 			log.u_bbr.flex4 = bbr_get_rtt(bbr, BBR_RTT_PROP);
2130 		log.u_bbr.flex5 = bbr->r_ctl.rc_bbr_last_startup_epoch;
2131 		log.u_bbr.flex6 = bbr->r_ctl.rc_lost_at_startup;
2132 		log.u_bbr.flex7 = (bbr->r_ctl.rc_target_at_state/1000);
2133 		log.u_bbr.lt_epoch = bbr->r_ctl.rc_level_state_extra;
2134 		log.u_bbr.pkts_out = bbr->r_ctl.rc_target_at_state;
2135 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2136 		    &bbr->rc_inp->inp_socket->so_rcv,
2137 		    &bbr->rc_inp->inp_socket->so_snd,
2138 		    BBR_LOG_STATE, 0,
2139 		    0, &log, false, &bbr->rc_tv);
2140 	}
2141 }
2142 
2143 static void
2144 bbr_log_rtt_shrinks(struct tcp_bbr *bbr, uint32_t cts, uint32_t applied,
2145 		    uint32_t rtt, uint32_t line, uint8_t reas, uint16_t cond)
2146 {
2147 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2148 		union tcp_log_stackspecific log;
2149 
2150 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2151 		log.u_bbr.flex1 = line;
2152 		log.u_bbr.flex2 = bbr->r_ctl.rc_rtt_shrinks;
2153 		log.u_bbr.flex3 = bbr->r_ctl.last_in_probertt;
2154 		log.u_bbr.flex4 = applied;
2155 		log.u_bbr.flex5 = rtt;
2156 		log.u_bbr.flex6 = bbr->r_ctl.rc_target_at_state;
2157 		log.u_bbr.flex7 = cond;
2158 		log.u_bbr.flex8 = reas;
2159 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2160 		    &bbr->rc_inp->inp_socket->so_rcv,
2161 		    &bbr->rc_inp->inp_socket->so_snd,
2162 		    BBR_LOG_RTT_SHRINKS, 0,
2163 		    0, &log, false, &bbr->rc_tv);
2164 	}
2165 }
2166 
2167 static void
2168 bbr_log_type_exit_rec(struct tcp_bbr *bbr)
2169 {
2170 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2171 		union tcp_log_stackspecific log;
2172 
2173 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2174 		log.u_bbr.flex1 = bbr->r_ctl.rc_recovery_start;
2175 		log.u_bbr.flex2 = bbr->r_ctl.rc_cwnd_on_ent;
2176 		log.u_bbr.flex5 = bbr->r_ctl.rc_target_at_state;
2177 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2178 		    &bbr->rc_inp->inp_socket->so_rcv,
2179 		    &bbr->rc_inp->inp_socket->so_snd,
2180 		    BBR_LOG_EXITREC, 0,
2181 		    0, &log, false, &bbr->rc_tv);
2182 	}
2183 }
2184 
2185 static void
2186 bbr_log_type_cwndupd(struct tcp_bbr *bbr, uint32_t bytes_this_ack, uint32_t chg,
2187     uint32_t prev_acked, int32_t meth, uint32_t target, uint32_t th_ack, int32_t line)
2188 {
2189 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2190 		union tcp_log_stackspecific log;
2191 
2192 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2193 		log.u_bbr.flex1 = line;
2194 		log.u_bbr.flex2 = prev_acked;
2195 		log.u_bbr.flex3 = bytes_this_ack;
2196 		log.u_bbr.flex4 = chg;
2197 		log.u_bbr.flex5 = th_ack;
2198 		log.u_bbr.flex6 = target;
2199 		log.u_bbr.flex8 = meth;
2200 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2201 		    &bbr->rc_inp->inp_socket->so_rcv,
2202 		    &bbr->rc_inp->inp_socket->so_snd,
2203 		    BBR_LOG_CWND, 0,
2204 		    0, &log, false, &bbr->rc_tv);
2205 	}
2206 }
2207 
2208 static void
2209 bbr_log_rtt_sample(struct tcp_bbr *bbr, uint32_t rtt, uint32_t tsin)
2210 {
2211 	/*
2212 	 * Log the rtt sample we are applying to the srtt algorithm in
2213 	 * useconds.
2214 	 */
2215 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2216 		union tcp_log_stackspecific log;
2217 
2218 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2219 		log.u_bbr.flex1 = rtt;
2220 		log.u_bbr.flex2 = bbr->r_ctl.rc_bbr_state_time;
2221 		log.u_bbr.flex3 = bbr->r_ctl.rc_ack_hdwr_delay;
2222 		log.u_bbr.flex4 = bbr->rc_tp->ts_offset;
2223 		log.u_bbr.flex5 = bbr->r_ctl.rc_target_at_state;
2224 		log.u_bbr.pkts_out = tcp_tv_to_mssectick(&bbr->rc_tv);
2225 		log.u_bbr.flex6 = tsin;
2226 		log.u_bbr.flex7 = 0;
2227 		log.u_bbr.flex8 = bbr->rc_ack_was_delayed;
2228 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2229 		    &bbr->rc_inp->inp_socket->so_rcv,
2230 		    &bbr->rc_inp->inp_socket->so_snd,
2231 		    TCP_LOG_RTT, 0,
2232 		    0, &log, false, &bbr->rc_tv);
2233 	}
2234 }
2235 
2236 static void
2237 bbr_log_type_pesist(struct tcp_bbr *bbr, uint32_t cts, uint32_t time_in, int32_t line, uint8_t enter_exit)
2238 {
2239 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2240 		union tcp_log_stackspecific log;
2241 
2242 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2243 		log.u_bbr.flex1 = time_in;
2244 		log.u_bbr.flex2 = line;
2245 		log.u_bbr.flex8 = enter_exit;
2246 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2247 		    &bbr->rc_inp->inp_socket->so_rcv,
2248 		    &bbr->rc_inp->inp_socket->so_snd,
2249 		    BBR_LOG_PERSIST, 0,
2250 		    0, &log, false, &bbr->rc_tv);
2251 	}
2252 }
2253 static void
2254 bbr_log_ack_clear(struct tcp_bbr *bbr, uint32_t cts)
2255 {
2256 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2257 		union tcp_log_stackspecific log;
2258 
2259 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2260 		log.u_bbr.flex1 = bbr->rc_tp->ts_recent_age;
2261 		log.u_bbr.flex2 = bbr->r_ctl.rc_rtt_shrinks;
2262 		log.u_bbr.flex3 = bbr->r_ctl.rc_probertt_int;
2263 		log.u_bbr.flex4 = bbr->r_ctl.rc_went_idle_time;
2264 		log.u_bbr.flex5 = bbr->r_ctl.rc_target_at_state;
2265 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2266 		    &bbr->rc_inp->inp_socket->so_rcv,
2267 		    &bbr->rc_inp->inp_socket->so_snd,
2268 		    BBR_LOG_ACKCLEAR, 0,
2269 		    0, &log, false, &bbr->rc_tv);
2270 	}
2271 }
2272 
2273 static void
2274 bbr_log_ack_event(struct tcp_bbr *bbr, struct tcphdr *th, struct tcpopt *to, uint32_t tlen,
2275 		  uint16_t nsegs, uint32_t cts, int32_t nxt_pkt, struct mbuf *m)
2276 {
2277 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2278 		union tcp_log_stackspecific log;
2279 		struct timeval tv;
2280 
2281 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2282 		log.u_bbr.flex1 = nsegs;
2283 		log.u_bbr.flex2 = bbr->r_ctl.rc_lost_bytes;
2284 		if (m) {
2285 			struct timespec ts;
2286 
2287 			log.u_bbr.flex3 = m->m_flags;
2288 			if (m->m_flags & M_TSTMP) {
2289 				mbuf_tstmp2timespec(m, &ts);
2290 				tv.tv_sec = ts.tv_sec;
2291 				tv.tv_usec = ts.tv_nsec / 1000;
2292 				log.u_bbr.lt_epoch = tcp_tv_to_usectick(&tv);
2293 			} else {
2294 				log.u_bbr.lt_epoch = 0;
2295 			}
2296 			if (m->m_flags & M_TSTMP_LRO) {
2297 				tv.tv_sec = m->m_pkthdr.rcv_tstmp / 1000000000;
2298 				tv.tv_usec = (m->m_pkthdr.rcv_tstmp % 1000000000) / 1000;
2299 				log.u_bbr.flex5 = tcp_tv_to_usectick(&tv);
2300 			} else {
2301 				/* No arrival timestamp */
2302 				log.u_bbr.flex5 = 0;
2303 			}
2304 
2305 			log.u_bbr.pkts_out = tcp_get_usecs(&tv);
2306 		} else {
2307 			log.u_bbr.flex3 = 0;
2308 			log.u_bbr.flex5 = 0;
2309 			log.u_bbr.flex6 = 0;
2310 			log.u_bbr.pkts_out = 0;
2311 		}
2312 		log.u_bbr.flex4 = bbr->r_ctl.rc_target_at_state;
2313 		log.u_bbr.flex7 = bbr->r_wanted_output;
2314 		log.u_bbr.flex8 = bbr->rc_in_persist;
2315 		TCP_LOG_EVENTP(bbr->rc_tp, th,
2316 		    &bbr->rc_inp->inp_socket->so_rcv,
2317 		    &bbr->rc_inp->inp_socket->so_snd,
2318 		    TCP_LOG_IN, 0,
2319 		    tlen, &log, true, &bbr->rc_tv);
2320 	}
2321 }
2322 
2323 static void
2324 bbr_log_doseg_done(struct tcp_bbr *bbr, uint32_t cts, int32_t nxt_pkt, int32_t did_out)
2325 {
2326 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2327 		union tcp_log_stackspecific log;
2328 
2329 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2330 		log.u_bbr.flex1 = did_out;
2331 		log.u_bbr.flex2 = nxt_pkt;
2332 		log.u_bbr.flex3 = bbr->r_ctl.rc_last_delay_val;
2333 		log.u_bbr.flex4 = bbr->r_ctl.rc_hpts_flags;
2334 		log.u_bbr.flex5 = bbr->r_ctl.rc_timer_exp;
2335 		log.u_bbr.flex6 = bbr->r_ctl.rc_lost_bytes;
2336 		log.u_bbr.flex7 = bbr->r_wanted_output;
2337 		log.u_bbr.flex8 = bbr->rc_in_persist;
2338 		log.u_bbr.pkts_out = bbr->r_ctl.highest_hdwr_delay;
2339 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2340 		    &bbr->rc_inp->inp_socket->so_rcv,
2341 		    &bbr->rc_inp->inp_socket->so_snd,
2342 		    BBR_LOG_DOSEG_DONE, 0,
2343 		    0, &log, true, &bbr->rc_tv);
2344 	}
2345 }
2346 
2347 static void
2348 bbr_log_enobuf_jmp(struct tcp_bbr *bbr, uint32_t len, uint32_t cts,
2349     int32_t line, uint32_t o_len, uint32_t segcnt, uint32_t segsiz)
2350 {
2351 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2352 		union tcp_log_stackspecific log;
2353 
2354 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2355 		log.u_bbr.flex1 = line;
2356 		log.u_bbr.flex2 = o_len;
2357 		log.u_bbr.flex3 = segcnt;
2358 		log.u_bbr.flex4 = segsiz;
2359 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2360 		    &bbr->rc_inp->inp_socket->so_rcv,
2361 		    &bbr->rc_inp->inp_socket->so_snd,
2362 		    BBR_LOG_ENOBUF_JMP, ENOBUFS,
2363 		    len, &log, true, &bbr->rc_tv);
2364 	}
2365 }
2366 
2367 static void
2368 bbr_log_to_processing(struct tcp_bbr *bbr, uint32_t cts, int32_t ret, int32_t timers, uint8_t hpts_calling)
2369 {
2370 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2371 		union tcp_log_stackspecific log;
2372 
2373 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2374 		log.u_bbr.flex1 = timers;
2375 		log.u_bbr.flex2 = ret;
2376 		log.u_bbr.flex3 = bbr->r_ctl.rc_timer_exp;
2377 		log.u_bbr.flex4 = bbr->r_ctl.rc_hpts_flags;
2378 		log.u_bbr.flex5 = cts;
2379 		log.u_bbr.flex6 = bbr->r_ctl.rc_target_at_state;
2380 		log.u_bbr.flex8 = hpts_calling;
2381 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2382 		    &bbr->rc_inp->inp_socket->so_rcv,
2383 		    &bbr->rc_inp->inp_socket->so_snd,
2384 		    BBR_LOG_TO_PROCESS, 0,
2385 		    0, &log, false, &bbr->rc_tv);
2386 	}
2387 }
2388 
2389 static void
2390 bbr_log_to_event(struct tcp_bbr *bbr, uint32_t cts, int32_t to_num)
2391 {
2392 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2393 		union tcp_log_stackspecific log;
2394 		uint64_t ar;
2395 
2396 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2397 		log.u_bbr.flex1 = bbr->bbr_timer_src;
2398 		log.u_bbr.flex2 = 0;
2399 		log.u_bbr.flex3 = bbr->r_ctl.rc_hpts_flags;
2400 		ar = (uint64_t)(bbr->r_ctl.rc_resend);
2401 		ar >>= 32;
2402 		ar &= 0x00000000ffffffff;
2403 		log.u_bbr.flex4 = (uint32_t)ar;
2404 		ar = (uint64_t)bbr->r_ctl.rc_resend;
2405 		ar &= 0x00000000ffffffff;
2406 		log.u_bbr.flex5 = (uint32_t)ar;
2407 		log.u_bbr.flex6 = TICKS_2_USEC(bbr->rc_tp->t_rxtcur);
2408 		log.u_bbr.flex8 = to_num;
2409 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2410 		    &bbr->rc_inp->inp_socket->so_rcv,
2411 		    &bbr->rc_inp->inp_socket->so_snd,
2412 		    BBR_LOG_RTO, 0,
2413 		    0, &log, false, &bbr->rc_tv);
2414 	}
2415 }
2416 
2417 static void
2418 bbr_log_startup_event(struct tcp_bbr *bbr, uint32_t cts, uint32_t flex1, uint32_t flex2, uint32_t flex3, uint8_t reason)
2419 {
2420 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2421 		union tcp_log_stackspecific log;
2422 
2423 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2424 		log.u_bbr.flex1 = flex1;
2425 		log.u_bbr.flex2 = flex2;
2426 		log.u_bbr.flex3 = flex3;
2427 		log.u_bbr.flex4 = 0;
2428 		log.u_bbr.flex5 = bbr->r_ctl.rc_target_at_state;
2429 		log.u_bbr.flex6 = bbr->r_ctl.rc_lost_at_startup;
2430 		log.u_bbr.flex8 = reason;
2431 		log.u_bbr.cur_del_rate = bbr->r_ctl.rc_bbr_lastbtlbw;
2432 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2433 		    &bbr->rc_inp->inp_socket->so_rcv,
2434 		    &bbr->rc_inp->inp_socket->so_snd,
2435 		    BBR_LOG_REDUCE, 0,
2436 		    0, &log, false, &bbr->rc_tv);
2437 	}
2438 }
2439 
2440 static void
2441 bbr_log_hpts_diag(struct tcp_bbr *bbr, uint32_t cts, struct hpts_diag *diag)
2442 {
2443 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2444 		union tcp_log_stackspecific log;
2445 
2446 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2447 		log.u_bbr.flex1 = diag->p_nxt_slot;
2448 		log.u_bbr.flex2 = diag->p_cur_slot;
2449 		log.u_bbr.flex3 = diag->slot_req;
2450 		log.u_bbr.flex4 = diag->inp_hptsslot;
2451 		log.u_bbr.flex5 = diag->slot_remaining;
2452 		log.u_bbr.flex6 = diag->need_new_to;
2453 		log.u_bbr.flex7 = diag->p_hpts_active;
2454 		log.u_bbr.flex8 = diag->p_on_min_sleep;
2455 		/* Hijack other fields as needed  */
2456 		log.u_bbr.epoch = diag->have_slept;
2457 		log.u_bbr.lt_epoch = diag->yet_to_sleep;
2458 		log.u_bbr.pkts_out = diag->co_ret;
2459 		log.u_bbr.applimited = diag->hpts_sleep_time;
2460 		log.u_bbr.delivered = diag->p_prev_slot;
2461 		log.u_bbr.inflight = diag->p_runningtick;
2462 		log.u_bbr.bw_inuse = diag->wheel_tick;
2463 		log.u_bbr.rttProp = diag->wheel_cts;
2464 		log.u_bbr.delRate = diag->maxticks;
2465 		log.u_bbr.cur_del_rate = diag->p_curtick;
2466 		log.u_bbr.cur_del_rate <<= 32;
2467 		log.u_bbr.cur_del_rate |= diag->p_lasttick;
2468 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2469 		    &bbr->rc_inp->inp_socket->so_rcv,
2470 		    &bbr->rc_inp->inp_socket->so_snd,
2471 		    BBR_LOG_HPTSDIAG, 0,
2472 		    0, &log, false, &bbr->rc_tv);
2473 	}
2474 }
2475 
2476 static void
2477 bbr_log_timer_var(struct tcp_bbr *bbr, int mode, uint32_t cts, uint32_t time_since_sent, uint32_t srtt,
2478     uint32_t thresh, uint32_t to)
2479 {
2480 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2481 		union tcp_log_stackspecific log;
2482 
2483 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2484 		log.u_bbr.flex1 = bbr->rc_tp->t_rttvar;
2485 		log.u_bbr.flex2 = time_since_sent;
2486 		log.u_bbr.flex3 = srtt;
2487 		log.u_bbr.flex4 = thresh;
2488 		log.u_bbr.flex5 = to;
2489 		log.u_bbr.flex6 = bbr->rc_tp->t_srtt;
2490 		log.u_bbr.flex8 = mode;
2491 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2492 		    &bbr->rc_inp->inp_socket->so_rcv,
2493 		    &bbr->rc_inp->inp_socket->so_snd,
2494 		    BBR_LOG_TIMERPREP, 0,
2495 		    0, &log, false, &bbr->rc_tv);
2496 	}
2497 }
2498 
2499 static void
2500 bbr_log_pacing_delay_calc(struct tcp_bbr *bbr, uint16_t gain, uint32_t len,
2501     uint32_t cts, uint32_t usecs, uint64_t bw, uint32_t override, int mod)
2502 {
2503 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2504 		union tcp_log_stackspecific log;
2505 
2506 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2507 		log.u_bbr.flex1 = usecs;
2508 		log.u_bbr.flex2 = len;
2509 		log.u_bbr.flex3 = (uint32_t)((bw >> 32) & 0x00000000ffffffff);
2510 		log.u_bbr.flex4 = (uint32_t)(bw & 0x00000000ffffffff);
2511 		if (override)
2512 			log.u_bbr.flex5 = (1 << 2);
2513 		else
2514 			log.u_bbr.flex5 = 0;
2515 		log.u_bbr.flex6 = override;
2516 		log.u_bbr.flex7 = gain;
2517 		log.u_bbr.flex8 = mod;
2518 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2519 		    &bbr->rc_inp->inp_socket->so_rcv,
2520 		    &bbr->rc_inp->inp_socket->so_snd,
2521 		    BBR_LOG_HPTSI_CALC, 0,
2522 		    len, &log, false, &bbr->rc_tv);
2523 	}
2524 }
2525 
2526 static void
2527 bbr_log_to_start(struct tcp_bbr *bbr, uint32_t cts, uint32_t to, int32_t slot, uint8_t which)
2528 {
2529 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2530 		union tcp_log_stackspecific log;
2531 
2532 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2533 
2534 		log.u_bbr.flex1 = bbr->bbr_timer_src;
2535 		log.u_bbr.flex2 = to;
2536 		log.u_bbr.flex3 = bbr->r_ctl.rc_hpts_flags;
2537 		log.u_bbr.flex4 = slot;
2538 		log.u_bbr.flex5 = bbr->rc_inp->inp_hptsslot;
2539 		log.u_bbr.flex6 = TICKS_2_USEC(bbr->rc_tp->t_rxtcur);
2540 		log.u_bbr.pkts_out = bbr->rc_inp->inp_flags2;
2541 		log.u_bbr.flex8 = which;
2542 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2543 		    &bbr->rc_inp->inp_socket->so_rcv,
2544 		    &bbr->rc_inp->inp_socket->so_snd,
2545 		    BBR_LOG_TIMERSTAR, 0,
2546 		    0, &log, false, &bbr->rc_tv);
2547 	}
2548 }
2549 
2550 static void
2551 bbr_log_thresh_choice(struct tcp_bbr *bbr, uint32_t cts, uint32_t thresh, uint32_t lro, uint32_t srtt, struct bbr_sendmap *rsm, uint8_t frm)
2552 {
2553 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2554 		union tcp_log_stackspecific log;
2555 
2556 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2557 		log.u_bbr.flex1 = thresh;
2558 		log.u_bbr.flex2 = lro;
2559 		log.u_bbr.flex3 = bbr->r_ctl.rc_reorder_ts;
2560 		log.u_bbr.flex4 = rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
2561 		log.u_bbr.flex5 = TICKS_2_USEC(bbr->rc_tp->t_rxtcur);
2562 		log.u_bbr.flex6 = srtt;
2563 		log.u_bbr.flex7 = bbr->r_ctl.rc_reorder_shift;
2564 		log.u_bbr.flex8 = frm;
2565 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2566 		    &bbr->rc_inp->inp_socket->so_rcv,
2567 		    &bbr->rc_inp->inp_socket->so_snd,
2568 		    BBR_LOG_THRESH_CALC, 0,
2569 		    0, &log, false, &bbr->rc_tv);
2570 	}
2571 }
2572 
2573 static void
2574 bbr_log_to_cancel(struct tcp_bbr *bbr, int32_t line, uint32_t cts, uint8_t hpts_removed)
2575 {
2576 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2577 		union tcp_log_stackspecific log;
2578 
2579 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2580 		log.u_bbr.flex1 = line;
2581 		log.u_bbr.flex2 = bbr->bbr_timer_src;
2582 		log.u_bbr.flex3 = bbr->r_ctl.rc_hpts_flags;
2583 		log.u_bbr.flex4 = bbr->rc_in_persist;
2584 		log.u_bbr.flex5 = bbr->r_ctl.rc_target_at_state;
2585 		log.u_bbr.flex6 = TICKS_2_USEC(bbr->rc_tp->t_rxtcur);
2586 		log.u_bbr.flex8 = hpts_removed;
2587 		log.u_bbr.pkts_out = bbr->rc_pacer_started;
2588 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2589 		    &bbr->rc_inp->inp_socket->so_rcv,
2590 		    &bbr->rc_inp->inp_socket->so_snd,
2591 		    BBR_LOG_TIMERCANC, 0,
2592 		    0, &log, false, &bbr->rc_tv);
2593 	}
2594 }
2595 
2596 
2597 static void
2598 bbr_log_tstmp_validation(struct tcp_bbr *bbr, uint64_t peer_delta, uint64_t delta)
2599 {
2600 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2601 		union tcp_log_stackspecific log;
2602 
2603 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2604 		log.u_bbr.flex1 = bbr->r_ctl.bbr_peer_tsratio;
2605 		log.u_bbr.flex2 = (peer_delta >> 32);
2606 		log.u_bbr.flex3 = (peer_delta & 0x00000000ffffffff);
2607 		log.u_bbr.flex4 = (delta >> 32);
2608 		log.u_bbr.flex5 = (delta & 0x00000000ffffffff);
2609 		log.u_bbr.flex7 = bbr->rc_ts_clock_set;
2610 		log.u_bbr.flex8 = bbr->rc_ts_cant_be_used;
2611 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2612 		    &bbr->rc_inp->inp_socket->so_rcv,
2613 		    &bbr->rc_inp->inp_socket->so_snd,
2614 		    BBR_LOG_TSTMP_VAL, 0,
2615 		    0, &log, false, &bbr->rc_tv);
2616 
2617 	}
2618 }
2619 
2620 static void
2621 bbr_log_type_tsosize(struct tcp_bbr *bbr, uint32_t cts, uint32_t tsosz, uint32_t tls, uint32_t old_val, uint32_t maxseg, int hdwr)
2622 {
2623 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2624 		union tcp_log_stackspecific log;
2625 
2626 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2627 		log.u_bbr.flex1 = tsosz;
2628 		log.u_bbr.flex2 = tls;
2629 		log.u_bbr.flex3 = tcp_min_hptsi_time;
2630 		log.u_bbr.flex4 = bbr->r_ctl.bbr_hptsi_bytes_min;
2631 		log.u_bbr.flex5 = old_val;
2632 		log.u_bbr.flex6 = maxseg;
2633 		log.u_bbr.flex7 = bbr->rc_no_pacing;
2634 		log.u_bbr.flex7 <<= 1;
2635 		log.u_bbr.flex7 |= bbr->rc_past_init_win;
2636 		if (hdwr)
2637 			log.u_bbr.flex8 = 0x80 | bbr->rc_use_google;
2638 		else
2639 			log.u_bbr.flex8 = bbr->rc_use_google;
2640 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2641 		    &bbr->rc_inp->inp_socket->so_rcv,
2642 		    &bbr->rc_inp->inp_socket->so_snd,
2643 		    BBR_LOG_BBRTSO, 0,
2644 		    0, &log, false, &bbr->rc_tv);
2645 	}
2646 }
2647 
2648 static void
2649 bbr_log_type_rsmclear(struct tcp_bbr *bbr, uint32_t cts, struct bbr_sendmap *rsm,
2650 		      uint32_t flags, uint32_t line)
2651 {
2652 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2653 		union tcp_log_stackspecific log;
2654 
2655 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2656 		log.u_bbr.flex1 = line;
2657 		log.u_bbr.flex2 = rsm->r_start;
2658 		log.u_bbr.flex3 = rsm->r_end;
2659 		log.u_bbr.flex4 = rsm->r_delivered;
2660 		log.u_bbr.flex5 = rsm->r_rtr_cnt;
2661 		log.u_bbr.flex6 = rsm->r_dupack;
2662 		log.u_bbr.flex7 = rsm->r_tim_lastsent[0];
2663 		log.u_bbr.flex8 = rsm->r_flags;
2664 		/* Hijack the pkts_out fids */
2665 		log.u_bbr.applimited = flags;
2666 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2667 		    &bbr->rc_inp->inp_socket->so_rcv,
2668 		    &bbr->rc_inp->inp_socket->so_snd,
2669 		    BBR_RSM_CLEARED, 0,
2670 		    0, &log, false, &bbr->rc_tv);
2671 	}
2672 }
2673 
2674 static void
2675 bbr_log_type_bbrupd(struct tcp_bbr *bbr, uint8_t flex8, uint32_t cts,
2676     uint32_t flex3, uint32_t flex2, uint32_t flex5,
2677     uint32_t flex6, uint32_t pkts_out, int flex7,
2678     uint32_t flex4, uint32_t flex1)
2679 {
2680 
2681 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2682 		union tcp_log_stackspecific log;
2683 
2684 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2685 		log.u_bbr.flex1 = flex1;
2686 		log.u_bbr.flex2 = flex2;
2687 		log.u_bbr.flex3 = flex3;
2688 		log.u_bbr.flex4 = flex4;
2689 		log.u_bbr.flex5 = flex5;
2690 		log.u_bbr.flex6 = flex6;
2691 		log.u_bbr.flex7 = flex7;
2692 		/* Hijack the pkts_out fids */
2693 		log.u_bbr.pkts_out = pkts_out;
2694 		log.u_bbr.flex8 = flex8;
2695 		if (bbr->rc_ack_was_delayed)
2696 			log.u_bbr.epoch = bbr->r_ctl.rc_ack_hdwr_delay;
2697 		else
2698 			log.u_bbr.epoch = 0;
2699 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2700 		    &bbr->rc_inp->inp_socket->so_rcv,
2701 		    &bbr->rc_inp->inp_socket->so_snd,
2702 		    BBR_LOG_BBRUPD, 0,
2703 		    flex2, &log, false, &bbr->rc_tv);
2704 	}
2705 }
2706 
2707 
2708 static void
2709 bbr_log_type_ltbw(struct tcp_bbr *bbr, uint32_t cts, int32_t reason,
2710 	uint32_t newbw, uint32_t obw, uint32_t diff,
2711 	uint32_t tim)
2712 {
2713 	if (/*bbr_verbose_logging && */(bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2714 		union tcp_log_stackspecific log;
2715 
2716 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2717 		log.u_bbr.flex1 = reason;
2718 		log.u_bbr.flex2 = newbw;
2719 		log.u_bbr.flex3 = obw;
2720 		log.u_bbr.flex4 = diff;
2721 		log.u_bbr.flex5 = bbr->r_ctl.rc_lt_lost;
2722 		log.u_bbr.flex6 = bbr->r_ctl.rc_lt_del;
2723 		log.u_bbr.flex7 = bbr->rc_lt_is_sampling;
2724 		log.u_bbr.pkts_out = tim;
2725 		log.u_bbr.bw_inuse = bbr->r_ctl.rc_lt_bw;
2726 		if (bbr->rc_lt_use_bw == 0)
2727 			log.u_bbr.epoch = bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_lt_epoch;
2728 		else
2729 			log.u_bbr.epoch = bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_lt_epoch_use;
2730 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2731 		    &bbr->rc_inp->inp_socket->so_rcv,
2732 		    &bbr->rc_inp->inp_socket->so_snd,
2733 		    BBR_LOG_BWSAMP, 0,
2734 		    0, &log, false, &bbr->rc_tv);
2735 	}
2736 }
2737 
2738 static inline void
2739 bbr_log_progress_event(struct tcp_bbr *bbr, struct tcpcb *tp, uint32_t tick, int event, int line)
2740 {
2741 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2742 		union tcp_log_stackspecific log;
2743 
2744 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2745 		log.u_bbr.flex1 = line;
2746 		log.u_bbr.flex2 = tick;
2747 		log.u_bbr.flex3 = tp->t_maxunacktime;
2748 		log.u_bbr.flex4 = tp->t_acktime;
2749 		log.u_bbr.flex8 = event;
2750 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2751 		    &bbr->rc_inp->inp_socket->so_rcv,
2752 		    &bbr->rc_inp->inp_socket->so_snd,
2753 		    BBR_LOG_PROGRESS, 0,
2754 		    0, &log, false, &bbr->rc_tv);
2755 	}
2756 }
2757 
2758 static void
2759 bbr_type_log_hdwr_pacing(struct tcp_bbr *bbr, const struct ifnet *ifp,
2760 			 uint64_t rate, uint64_t hw_rate, int line, uint32_t cts,
2761 			 int error)
2762 {
2763 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2764 		union tcp_log_stackspecific log;
2765 
2766 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2767 		log.u_bbr.flex1 = ((hw_rate >> 32) & 0x00000000ffffffff);
2768 		log.u_bbr.flex2 = (hw_rate & 0x00000000ffffffff);
2769 		log.u_bbr.flex3 = (((uint64_t)ifp  >> 32) & 0x00000000ffffffff);
2770 		log.u_bbr.flex4 = ((uint64_t)ifp & 0x00000000ffffffff);
2771 		log.u_bbr.bw_inuse = rate;
2772 		log.u_bbr.flex5 = line;
2773 		log.u_bbr.flex6 = error;
2774 		log.u_bbr.flex8 = bbr->skip_gain;
2775 		log.u_bbr.flex8 <<= 1;
2776 		log.u_bbr.flex8 |= bbr->gain_is_limited;
2777 		log.u_bbr.flex8 <<= 1;
2778 		log.u_bbr.flex8 |= bbr->bbr_hdrw_pacing;
2779 		log.u_bbr.pkts_out = bbr->rc_tp->t_maxseg;
2780 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2781 		    &bbr->rc_inp->inp_socket->so_rcv,
2782 		    &bbr->rc_inp->inp_socket->so_snd,
2783 		    BBR_LOG_HDWR_PACE, 0,
2784 		    0, &log, false, &bbr->rc_tv);
2785 	}
2786 }
2787 
2788 static void
2789 bbr_log_type_bbrsnd(struct tcp_bbr *bbr, uint32_t len, uint32_t slot, uint32_t del_by, uint32_t cts, uint32_t line, uint32_t prev_delay)
2790 {
2791 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2792 		union tcp_log_stackspecific log;
2793 
2794 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2795 		log.u_bbr.flex1 = slot;
2796 		log.u_bbr.flex2 = del_by;
2797 		log.u_bbr.flex3 = prev_delay;
2798 		log.u_bbr.flex4 = line;
2799 		log.u_bbr.flex5 = bbr->r_ctl.rc_last_delay_val;
2800 		log.u_bbr.flex6 = bbr->r_ctl.rc_hptsi_agg_delay;
2801 		log.u_bbr.flex7 = (0x0000ffff & bbr->r_ctl.rc_hpts_flags);
2802 		log.u_bbr.flex8 = bbr->rc_in_persist;
2803 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2804 		    &bbr->rc_inp->inp_socket->so_rcv,
2805 		    &bbr->rc_inp->inp_socket->so_snd,
2806 		    BBR_LOG_BBRSND, 0,
2807 		    len, &log, false, &bbr->rc_tv);
2808 	}
2809 }
2810 
2811 static void
2812 bbr_log_type_bbrrttprop(struct tcp_bbr *bbr, uint32_t t, uint32_t end, uint32_t tsconv, uint32_t cts, int32_t match, uint32_t seq, uint8_t flags)
2813 {
2814 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2815 		union tcp_log_stackspecific log;
2816 
2817 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2818 		log.u_bbr.flex1 = bbr->r_ctl.rc_delivered;
2819 		log.u_bbr.flex2 = 0;
2820 		log.u_bbr.flex3 = bbr->r_ctl.rc_lowest_rtt;
2821 		log.u_bbr.flex4 = end;
2822 		log.u_bbr.flex5 = seq;
2823 		log.u_bbr.flex6 = t;
2824 		log.u_bbr.flex7 = match;
2825 		log.u_bbr.flex8 = flags;
2826 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2827 		    &bbr->rc_inp->inp_socket->so_rcv,
2828 		    &bbr->rc_inp->inp_socket->so_snd,
2829 		    BBR_LOG_BBRRTT, 0,
2830 		    0, &log, false, &bbr->rc_tv);
2831 	}
2832 }
2833 
2834 static void
2835 bbr_log_exit_gain(struct tcp_bbr *bbr, uint32_t cts, int32_t entry_method)
2836 {
2837 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2838 		union tcp_log_stackspecific log;
2839 
2840 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2841 		log.u_bbr.flex1 = bbr->r_ctl.rc_target_at_state;
2842 		log.u_bbr.flex2 = (bbr->rc_tp->t_maxseg - bbr->rc_last_options);
2843 		log.u_bbr.flex3 = bbr->r_ctl.gain_epoch;
2844 		log.u_bbr.flex4 = bbr->r_ctl.rc_pace_max_segs;
2845 		log.u_bbr.flex5 = bbr->r_ctl.rc_pace_min_segs;
2846 		log.u_bbr.flex6 = bbr->r_ctl.rc_bbr_state_atflight;
2847 		log.u_bbr.flex7 = 0;
2848 		log.u_bbr.flex8 = entry_method;
2849 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2850 		    &bbr->rc_inp->inp_socket->so_rcv,
2851 		    &bbr->rc_inp->inp_socket->so_snd,
2852 		    BBR_LOG_EXIT_GAIN, 0,
2853 		    0, &log, false, &bbr->rc_tv);
2854 	}
2855 }
2856 
2857 static void
2858 bbr_log_settings_change(struct tcp_bbr *bbr, int settings_desired)
2859 {
2860 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2861 		union tcp_log_stackspecific log;
2862 
2863 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2864 		/* R-HU */
2865 		log.u_bbr.flex1 = 0;
2866 		log.u_bbr.flex2 = 0;
2867 		log.u_bbr.flex3 = 0;
2868 		log.u_bbr.flex4 = 0;
2869 		log.u_bbr.flex7 = 0;
2870 		log.u_bbr.flex8 = settings_desired;
2871 
2872 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2873 		    &bbr->rc_inp->inp_socket->so_rcv,
2874 		    &bbr->rc_inp->inp_socket->so_snd,
2875 		    BBR_LOG_SETTINGS_CHG, 0,
2876 		    0, &log, false, &bbr->rc_tv);
2877 	}
2878 }
2879 
2880 /*
2881  * Returns the bw from the our filter.
2882  */
2883 static inline uint64_t
2884 bbr_get_full_bw(struct tcp_bbr *bbr)
2885 {
2886 	uint64_t bw;
2887 
2888 	bw = get_filter_value(&bbr->r_ctl.rc_delrate);
2889 
2890 	return (bw);
2891 }
2892 
2893 static inline void
2894 bbr_set_pktepoch(struct tcp_bbr *bbr, uint32_t cts, int32_t line)
2895 {
2896 	uint64_t calclr;
2897 	uint32_t lost, del;
2898 
2899 	if (bbr->r_ctl.rc_lost > bbr->r_ctl.rc_lost_at_pktepoch)
2900 		lost = bbr->r_ctl.rc_lost - bbr->r_ctl.rc_lost_at_pktepoch;
2901 	else
2902 		lost = 0;
2903 	del = bbr->r_ctl.rc_delivered - bbr->r_ctl.rc_pkt_epoch_del;
2904 	if (lost == 0)  {
2905 		calclr = 0;
2906 	} else if (del) {
2907 		calclr = lost;
2908 		calclr *= (uint64_t)1000;
2909 		calclr /= (uint64_t)del;
2910 	} else {
2911 		/* Nothing delivered? 100.0% loss */
2912 		calclr = 1000;
2913 	}
2914 	bbr->r_ctl.rc_pkt_epoch_loss_rate =  (uint32_t)calclr;
2915 	if (IN_RECOVERY(bbr->rc_tp->t_flags))
2916 		bbr->r_ctl.recovery_lr += (uint32_t)calclr;
2917 	bbr->r_ctl.rc_pkt_epoch++;
2918 	if (bbr->rc_no_pacing &&
2919 	    (bbr->r_ctl.rc_pkt_epoch >= bbr->no_pacing_until)) {
2920 		bbr->rc_no_pacing = 0;
2921 		tcp_bbr_tso_size_check(bbr, cts);
2922 	}
2923 	bbr->r_ctl.rc_pkt_epoch_rtt = bbr_calc_time(cts, bbr->r_ctl.rc_pkt_epoch_time);
2924 	bbr->r_ctl.rc_pkt_epoch_time = cts;
2925 	/* What was our loss rate */
2926 	bbr_log_pkt_epoch(bbr, cts, line, lost, del);
2927 	bbr->r_ctl.rc_pkt_epoch_del = bbr->r_ctl.rc_delivered;
2928 	bbr->r_ctl.rc_lost_at_pktepoch = bbr->r_ctl.rc_lost;
2929 }
2930 
2931 static inline void
2932 bbr_set_epoch(struct tcp_bbr *bbr, uint32_t cts, int32_t line)
2933 {
2934 	uint32_t epoch_time;
2935 
2936 	/* Tick the RTT clock */
2937 	bbr->r_ctl.rc_rtt_epoch++;
2938 	epoch_time = cts - bbr->r_ctl.rc_rcv_epoch_start;
2939 	bbr_log_time_epoch(bbr, cts, line, epoch_time);
2940 	bbr->r_ctl.rc_rcv_epoch_start = cts;
2941 }
2942 
2943 
2944 static inline void
2945 bbr_isit_a_pkt_epoch(struct tcp_bbr *bbr, uint32_t cts, struct bbr_sendmap *rsm, int32_t line, int32_t cum_acked)
2946 {
2947 	if (SEQ_GEQ(rsm->r_delivered, bbr->r_ctl.rc_pkt_epoch_del)) {
2948 		bbr->rc_is_pkt_epoch_now = 1;
2949 	}
2950 }
2951 
2952 /*
2953  * Returns the bw from either the b/w filter
2954  * or from the lt_bw (if the connection is being
2955  * policed).
2956  */
2957 static inline uint64_t
2958 __bbr_get_bw(struct tcp_bbr *bbr)
2959 {
2960 	uint64_t bw, min_bw;
2961 	uint64_t rtt;
2962 	int gm_measure_cnt = 1;
2963 
2964 	/*
2965 	 * For startup we make, like google, a
2966 	 * minimum b/w. This is generated from the
2967 	 * IW and the rttProp. We do fall back to srtt
2968 	 * if for some reason (initial handshake) we don't
2969 	 * have a rttProp. We, in the worst case, fall back
2970 	 * to the configured min_bw (rc_initial_hptsi_bw).
2971 	 */
2972 	if (bbr->rc_bbr_state == BBR_STATE_STARTUP) {
2973 		/* Attempt first to use rttProp */
2974 		rtt = (uint64_t)get_filter_value_small(&bbr->r_ctl.rc_rttprop);
2975 		if (rtt && (rtt < 0xffffffff)) {
2976 measure:
2977 			min_bw = (uint64_t)(bbr_initial_cwnd(bbr, bbr->rc_tp)) *
2978 				((uint64_t)1000000);
2979 			min_bw /= rtt;
2980 			if (min_bw < bbr->r_ctl.rc_initial_hptsi_bw) {
2981 				min_bw = bbr->r_ctl.rc_initial_hptsi_bw;
2982 			}
2983 
2984 		} else if (bbr->rc_tp->t_srtt != 0) {
2985 			/* No rttProp, use srtt? */
2986 			rtt = bbr_get_rtt(bbr, BBR_SRTT);
2987 			goto measure;
2988 		} else {
2989 			min_bw = bbr->r_ctl.rc_initial_hptsi_bw;
2990 		}
2991 	} else
2992 		min_bw = 0;
2993 
2994 	if ((bbr->rc_past_init_win == 0) &&
2995 	    (bbr->r_ctl.rc_delivered > bbr_initial_cwnd(bbr, bbr->rc_tp)))
2996 		bbr->rc_past_init_win = 1;
2997 	if ((bbr->rc_use_google)  && (bbr->r_ctl.r_measurement_count >= 1))
2998 		gm_measure_cnt = 0;
2999 	if (gm_measure_cnt &&
3000 	    ((bbr->r_ctl.r_measurement_count < bbr_min_measurements_req) ||
3001 	     (bbr->rc_past_init_win == 0))) {
3002 		/* For google we use our guess rate until we get 1 measurement */
3003 
3004 use_initial_window:
3005 		rtt = (uint64_t)get_filter_value_small(&bbr->r_ctl.rc_rttprop);
3006 		if (rtt && (rtt < 0xffffffff)) {
3007 			/*
3008 			 * We have an RTT measurment. Use that in
3009 			 * combination with our initial window to calculate
3010 			 * a b/w.
3011 			 */
3012 			bw = (uint64_t)(bbr_initial_cwnd(bbr, bbr->rc_tp)) *
3013 				((uint64_t)1000000);
3014 			bw /= rtt;
3015 			if (bw < bbr->r_ctl.rc_initial_hptsi_bw) {
3016 				bw = bbr->r_ctl.rc_initial_hptsi_bw;
3017 			}
3018 		} else {
3019 			/* Drop back to the 40 and punt to a default */
3020 			bw = bbr->r_ctl.rc_initial_hptsi_bw;
3021 		}
3022 		if (bw < 1)
3023 			/* Probably should panic */
3024 			bw = 1;
3025 		if (bw > min_bw)
3026 			return (bw);
3027 		else
3028 			return (min_bw);
3029 	}
3030 	if (bbr->rc_lt_use_bw)
3031 		bw = bbr->r_ctl.rc_lt_bw;
3032 	else if (bbr->r_recovery_bw && (bbr->rc_use_google == 0))
3033 		bw = bbr->r_ctl.red_bw;
3034 	else
3035 		bw = get_filter_value(&bbr->r_ctl.rc_delrate);
3036 	if (bbr->rc_tp->t_peakrate_thr && (bbr->rc_use_google == 0)) {
3037 		/*
3038 		 * Enforce user set rate limit, keep in mind that
3039 		 * t_peakrate_thr is in B/s already
3040 		 */
3041 		bw = uqmin((uint64_t)bbr->rc_tp->t_peakrate_thr, bw);
3042 	}
3043 	if (bw == 0) {
3044 		/* We should not be at 0, go to the initial window then  */
3045 		goto use_initial_window;
3046 	}
3047 	if (bw < 1)
3048 		/* Probably should panic */
3049 		bw = 1;
3050 	if (bw < min_bw)
3051 		bw = min_bw;
3052 	return (bw);
3053 }
3054 
3055 static inline uint64_t
3056 bbr_get_bw(struct tcp_bbr *bbr)
3057 {
3058 	uint64_t bw;
3059 
3060 	bw = __bbr_get_bw(bbr);
3061 	return (bw);
3062 }
3063 
3064 static inline void
3065 bbr_reset_lt_bw_interval(struct tcp_bbr *bbr, uint32_t cts)
3066 {
3067 	bbr->r_ctl.rc_lt_epoch = bbr->r_ctl.rc_pkt_epoch;
3068 	bbr->r_ctl.rc_lt_time = bbr->r_ctl.rc_del_time;
3069 	bbr->r_ctl.rc_lt_del = bbr->r_ctl.rc_delivered;
3070 	bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
3071 }
3072 
3073 static inline void
3074 bbr_reset_lt_bw_sampling(struct tcp_bbr *bbr, uint32_t cts)
3075 {
3076 	bbr->rc_lt_is_sampling = 0;
3077 	bbr->rc_lt_use_bw = 0;
3078 	bbr->r_ctl.rc_lt_bw = 0;
3079 	bbr_reset_lt_bw_interval(bbr, cts);
3080 }
3081 
3082 static inline void
3083 bbr_lt_bw_samp_done(struct tcp_bbr *bbr, uint64_t bw, uint32_t cts, uint32_t timin)
3084 {
3085 	uint64_t diff;
3086 
3087 	/* Do we have a previous sample? */
3088 	if (bbr->r_ctl.rc_lt_bw) {
3089 		/* Get the diff in bytes per second */
3090 		if (bbr->r_ctl.rc_lt_bw > bw)
3091 			diff = bbr->r_ctl.rc_lt_bw - bw;
3092 		else
3093 			diff = bw - bbr->r_ctl.rc_lt_bw;
3094 		if ((diff <= bbr_lt_bw_diff) ||
3095 		    (diff <= (bbr->r_ctl.rc_lt_bw / bbr_lt_bw_ratio))) {
3096 			/* Consider us policed */
3097 			uint32_t saved_bw;
3098 
3099 			saved_bw = (uint32_t)bbr->r_ctl.rc_lt_bw;
3100 			bbr->r_ctl.rc_lt_bw = (bw + bbr->r_ctl.rc_lt_bw) / 2;	/* average of two */
3101 			bbr->rc_lt_use_bw = 1;
3102 			bbr->r_ctl.rc_bbr_hptsi_gain = BBR_UNIT;
3103 			/*
3104 			 * Use pkt based epoch for measuring length of
3105 			 * policer up
3106 			 */
3107 			bbr->r_ctl.rc_lt_epoch_use = bbr->r_ctl.rc_pkt_epoch;
3108 			/*
3109 			 * reason 4 is we need to start consider being
3110 			 * policed
3111 			 */
3112 			bbr_log_type_ltbw(bbr, cts, 4, (uint32_t)bw, saved_bw, (uint32_t)diff, timin);
3113 			return;
3114 		}
3115 	}
3116 	bbr->r_ctl.rc_lt_bw = bw;
3117 	bbr_reset_lt_bw_interval(bbr, cts);
3118 	bbr_log_type_ltbw(bbr, cts, 5, 0, (uint32_t)bw, 0, timin);
3119 }
3120 
3121 /*
3122  * RRS: Copied from user space!
3123  * Calculate a uniformly distributed random number less than upper_bound
3124  * avoiding "modulo bias".
3125  *
3126  * Uniformity is achieved by generating new random numbers until the one
3127  * returned is outside the range [0, 2**32 % upper_bound).  This
3128  * guarantees the selected random number will be inside
3129  * [2**32 % upper_bound, 2**32) which maps back to [0, upper_bound)
3130  * after reduction modulo upper_bound.
3131  */
3132 static uint32_t
3133 arc4random_uniform(uint32_t upper_bound)
3134 {
3135 	uint32_t r, min;
3136 
3137 	if (upper_bound < 2)
3138 		return 0;
3139 
3140 	/* 2**32 % x == (2**32 - x) % x */
3141 	min = -upper_bound % upper_bound;
3142 
3143 	/*
3144 	 * This could theoretically loop forever but each retry has
3145 	 * p > 0.5 (worst case, usually far better) of selecting a
3146 	 * number inside the range we need, so it should rarely need
3147 	 * to re-roll.
3148 	 */
3149 	for (;;) {
3150 		r = arc4random();
3151 		if (r >= min)
3152 			break;
3153 	}
3154 
3155 	return r % upper_bound;
3156 }
3157 
3158 static void
3159 bbr_randomize_extra_state_time(struct tcp_bbr *bbr)
3160 {
3161 	uint32_t ran, deduct;
3162 
3163 	ran = arc4random_uniform(bbr_rand_ot);
3164 	if (ran) {
3165 		deduct = bbr->r_ctl.rc_level_state_extra / ran;
3166 		bbr->r_ctl.rc_level_state_extra -= deduct;
3167 	}
3168 }
3169 /*
3170  * Return randomly the starting state
3171  * to use in probebw.
3172  */
3173 static uint8_t
3174 bbr_pick_probebw_substate(struct tcp_bbr *bbr, uint32_t cts)
3175 {
3176 	uint32_t ran;
3177 	uint8_t ret_val;
3178 
3179 	/* Initialize the offset to 0 */
3180 	bbr->r_ctl.rc_exta_time_gd = 0;
3181 	bbr->rc_hit_state_1 = 0;
3182 	bbr->r_ctl.rc_level_state_extra = 0;
3183 	ran = arc4random_uniform((BBR_SUBSTATE_COUNT-1));
3184 	/*
3185 	 * The math works funny here :) the return value is used to set the
3186 	 * substate and then the state change is called which increments by
3187 	 * one. So if we return 1 (DRAIN) we will increment to 2 (LEVEL1) when
3188 	 * we fully enter the state. Note that the (8 - 1 - ran) assures that
3189 	 * we return 1 - 7, so we dont return 0 and end up starting in
3190 	 * state 1 (DRAIN).
3191 	 */
3192 	ret_val = BBR_SUBSTATE_COUNT - 1 - ran;
3193 	/* Set an epoch */
3194 	if ((cts - bbr->r_ctl.rc_rcv_epoch_start) >= bbr_get_rtt(bbr, BBR_RTT_PROP))
3195 		bbr_set_epoch(bbr, cts, __LINE__);
3196 
3197 	bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
3198 	return (ret_val);
3199 }
3200 
3201 static void
3202 bbr_lt_bw_sampling(struct tcp_bbr *bbr, uint32_t cts, int32_t loss_detected)
3203 {
3204 	uint32_t diff, d_time;
3205 	uint64_t del_time, bw, lost, delivered;
3206 
3207 	if (bbr->r_use_policer == 0)
3208 		return;
3209 	if (bbr->rc_lt_use_bw) {
3210 		/* We are using lt bw do we stop yet? */
3211 		diff = bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_lt_epoch_use;
3212 		if (diff > bbr_lt_bw_max_rtts) {
3213 			/* Reset it all */
3214 reset_all:
3215 			bbr_reset_lt_bw_sampling(bbr, cts);
3216 			if (bbr->rc_filled_pipe) {
3217 				bbr_set_epoch(bbr, cts, __LINE__);
3218 				bbr->rc_bbr_substate = bbr_pick_probebw_substate(bbr, cts);
3219 				bbr_substate_change(bbr, cts, __LINE__, 0);
3220 				bbr->rc_bbr_state = BBR_STATE_PROBE_BW;
3221 				bbr_log_type_statechange(bbr, cts, __LINE__);
3222 			} else {
3223 				/*
3224 				 * This should not happen really
3225 				 * unless we remove the startup/drain
3226 				 * restrictions above.
3227 				 */
3228 				bbr->rc_bbr_state = BBR_STATE_STARTUP;
3229 				bbr_set_epoch(bbr, cts, __LINE__);
3230 				bbr->r_ctl.rc_bbr_state_time = cts;
3231 				bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
3232 				bbr->r_ctl.rc_bbr_hptsi_gain = bbr->r_ctl.rc_startup_pg;
3233 				bbr->r_ctl.rc_bbr_cwnd_gain = bbr->r_ctl.rc_startup_pg;
3234 				bbr_set_state_target(bbr, __LINE__);
3235 				bbr_log_type_statechange(bbr, cts, __LINE__);
3236 			}
3237 			/* reason 0 is to stop using lt-bw */
3238 			bbr_log_type_ltbw(bbr, cts, 0, 0, 0, 0, 0);
3239 			return;
3240 		}
3241 		if (bbr_lt_intvl_fp == 0) {
3242 			/* Not doing false-postive detection */
3243 			return;
3244 		}
3245 		/* False positive detection */
3246 		if (diff == bbr_lt_intvl_fp) {
3247 			/* At bbr_lt_intvl_fp we record the lost */
3248 			bbr->r_ctl.rc_lt_del = bbr->r_ctl.rc_delivered;
3249 			bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
3250 		} else if (diff > (bbr_lt_intvl_min_rtts + bbr_lt_intvl_fp)) {
3251 			/* Now is our loss rate still high? */
3252 			lost = bbr->r_ctl.rc_lost - bbr->r_ctl.rc_lt_lost;
3253 			delivered = bbr->r_ctl.rc_delivered - bbr->r_ctl.rc_lt_del;
3254 			if ((delivered == 0) ||
3255 			    (((lost * 1000)/delivered) < bbr_lt_fd_thresh)) {
3256 				/* No still below our threshold */
3257 				bbr_log_type_ltbw(bbr, cts, 7, lost, delivered, 0, 0);
3258 			} else {
3259 				/* Yikes its still high, it must be a false positive */
3260 				bbr_log_type_ltbw(bbr, cts, 8, lost, delivered, 0, 0);
3261 				goto reset_all;
3262 			}
3263 		}
3264 		return;
3265 	}
3266 	/*
3267 	 * Wait for the first loss before sampling, to let the policer
3268 	 * exhaust its tokens and estimate the steady-state rate allowed by
3269 	 * the policer. Starting samples earlier includes bursts that
3270 	 * over-estimate the bw.
3271 	 */
3272 	if (bbr->rc_lt_is_sampling == 0) {
3273 		/* reason 1 is to begin doing the sampling  */
3274 		if (loss_detected == 0)
3275 			return;
3276 		bbr_reset_lt_bw_interval(bbr, cts);
3277 		bbr->rc_lt_is_sampling = 1;
3278 		bbr_log_type_ltbw(bbr, cts, 1, 0, 0, 0, 0);
3279 		return;
3280 	}
3281 	/* Now how long were we delivering long term last> */
3282 	if (TSTMP_GEQ(bbr->r_ctl.rc_del_time, bbr->r_ctl.rc_lt_time))
3283 		d_time = bbr->r_ctl.rc_del_time - bbr->r_ctl.rc_lt_time;
3284 	else
3285 		d_time = 0;
3286 
3287 	/* To avoid underestimates, reset sampling if we run out of data. */
3288 	if (bbr->r_ctl.r_app_limited_until) {
3289 		/* Can not measure in app-limited state */
3290 		bbr_reset_lt_bw_sampling(bbr, cts);
3291 		/* reason 2 is to reset sampling due to app limits  */
3292 		bbr_log_type_ltbw(bbr, cts, 2, 0, 0, 0, d_time);
3293 		return;
3294 	}
3295 	diff = bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_lt_epoch;
3296 	if (diff < bbr_lt_intvl_min_rtts) {
3297 		/*
3298 		 * need more samples (we don't
3299 		 * start on a round like linux so
3300 		 * we need 1 more).
3301 		 */
3302 		/* 6 is not_enough time or no-loss */
3303 		bbr_log_type_ltbw(bbr, cts, 6, 0, 0, 0, d_time);
3304 		return;
3305 	}
3306 	if (diff > (4 * bbr_lt_intvl_min_rtts)) {
3307 		/*
3308 		 * For now if we wait too long, reset all sampling. We need
3309 		 * to do some research here, its possible that we should
3310 		 * base this on how much loss as occurred.. something like
3311 		 * if its under 10% (or some thresh) reset all otherwise
3312 		 * don't.  Thats for phase II I guess.
3313 		 */
3314 		bbr_reset_lt_bw_sampling(bbr, cts);
3315  		/* reason 3 is to reset sampling due too long of sampling */
3316 		bbr_log_type_ltbw(bbr, cts, 3, 0, 0, 0, d_time);
3317 		return;
3318 	}
3319 	/*
3320 	 * End sampling interval when a packet is lost, so we estimate the
3321 	 * policer tokens were exhausted. Stopping the sampling before the
3322 	 * tokens are exhausted under-estimates the policed rate.
3323 	 */
3324 	if (loss_detected == 0) {
3325 		/* 6 is not_enough time or no-loss */
3326 		bbr_log_type_ltbw(bbr, cts, 6, 0, 0, 0, d_time);
3327 		return;
3328 	}
3329 	/* Calculate packets lost and delivered in sampling interval. */
3330 	lost = bbr->r_ctl.rc_lost - bbr->r_ctl.rc_lt_lost;
3331 	delivered = bbr->r_ctl.rc_delivered - bbr->r_ctl.rc_lt_del;
3332 	if ((delivered == 0) ||
3333 	    (((lost * 1000)/delivered) < bbr_lt_loss_thresh)) {
3334 		bbr_log_type_ltbw(bbr, cts, 6, lost, delivered, 0, d_time);
3335 		return;
3336 	}
3337 	if (d_time < 1000) {
3338 		/* Not enough time. wait */
3339 		/* 6 is not_enough time or no-loss */
3340 		bbr_log_type_ltbw(bbr, cts, 6, 0, 0, 0, d_time);
3341 		return;
3342 	}
3343 	if (d_time >= (0xffffffff / USECS_IN_MSEC)) {
3344 		/* Too long */
3345 		bbr_reset_lt_bw_sampling(bbr, cts);
3346  		/* reason 3 is to reset sampling due too long of sampling */
3347 		bbr_log_type_ltbw(bbr, cts, 3, 0, 0, 0, d_time);
3348 		return;
3349 	}
3350 	del_time = d_time;
3351 	bw = delivered;
3352 	bw *= (uint64_t)USECS_IN_SECOND;
3353 	bw /= del_time;
3354 	bbr_lt_bw_samp_done(bbr, bw, cts, d_time);
3355 }
3356 
3357 /*
3358  * Allocate a sendmap from our zone.
3359  */
3360 static struct bbr_sendmap *
3361 bbr_alloc(struct tcp_bbr *bbr)
3362 {
3363 	struct bbr_sendmap *rsm;
3364 
3365 	BBR_STAT_INC(bbr_to_alloc);
3366 	rsm = uma_zalloc(bbr_zone, (M_NOWAIT | M_ZERO));
3367 	if (rsm) {
3368 		bbr->r_ctl.rc_num_maps_alloced++;
3369 		return (rsm);
3370 	}
3371 	if (bbr->r_ctl.rc_free_cnt) {
3372 		BBR_STAT_INC(bbr_to_alloc_emerg);
3373 		rsm = TAILQ_FIRST(&bbr->r_ctl.rc_free);
3374 		TAILQ_REMOVE(&bbr->r_ctl.rc_free, rsm, r_next);
3375 		bbr->r_ctl.rc_free_cnt--;
3376 		return (rsm);
3377 	}
3378 	BBR_STAT_INC(bbr_to_alloc_failed);
3379 	return (NULL);
3380 }
3381 
3382 static struct bbr_sendmap *
3383 bbr_alloc_full_limit(struct tcp_bbr *bbr)
3384 {
3385 	if ((V_tcp_map_entries_limit > 0) &&
3386 	    (bbr->r_ctl.rc_num_maps_alloced >= V_tcp_map_entries_limit)) {
3387 		BBR_STAT_INC(bbr_alloc_limited);
3388 		if (!bbr->alloc_limit_reported) {
3389 			bbr->alloc_limit_reported = 1;
3390 			BBR_STAT_INC(bbr_alloc_limited_conns);
3391 		}
3392 		return (NULL);
3393 	}
3394 	return (bbr_alloc(bbr));
3395 }
3396 
3397 
3398 /* wrapper to allocate a sendmap entry, subject to a specific limit */
3399 static struct bbr_sendmap *
3400 bbr_alloc_limit(struct tcp_bbr *bbr, uint8_t limit_type)
3401 {
3402 	struct bbr_sendmap *rsm;
3403 
3404 	if (limit_type) {
3405 		/* currently there is only one limit type */
3406 		if (V_tcp_map_split_limit > 0 &&
3407 		    bbr->r_ctl.rc_num_split_allocs >= V_tcp_map_split_limit) {
3408 			BBR_STAT_INC(bbr_split_limited);
3409 			if (!bbr->alloc_limit_reported) {
3410 				bbr->alloc_limit_reported = 1;
3411 				BBR_STAT_INC(bbr_alloc_limited_conns);
3412 			}
3413 			return (NULL);
3414 		}
3415 	}
3416 
3417 	/* allocate and mark in the limit type, if set */
3418 	rsm = bbr_alloc(bbr);
3419 	if (rsm != NULL && limit_type) {
3420 		rsm->r_limit_type = limit_type;
3421 		bbr->r_ctl.rc_num_split_allocs++;
3422 	}
3423 	return (rsm);
3424 }
3425 
3426 static void
3427 bbr_free(struct tcp_bbr *bbr, struct bbr_sendmap *rsm)
3428 {
3429 	if (rsm->r_limit_type) {
3430 		/* currently there is only one limit type */
3431 		bbr->r_ctl.rc_num_split_allocs--;
3432 	}
3433 	if (rsm->r_is_smallmap)
3434 		bbr->r_ctl.rc_num_small_maps_alloced--;
3435 	if (bbr->r_ctl.rc_tlp_send == rsm)
3436 		bbr->r_ctl.rc_tlp_send = NULL;
3437 	if (bbr->r_ctl.rc_resend == rsm) {
3438 		bbr->r_ctl.rc_resend = NULL;
3439 	}
3440 	if (bbr->r_ctl.rc_next == rsm)
3441 		bbr->r_ctl.rc_next = NULL;
3442 	if (bbr->r_ctl.rc_sacklast == rsm)
3443 		bbr->r_ctl.rc_sacklast = NULL;
3444 	if (bbr->r_ctl.rc_free_cnt < bbr_min_req_free) {
3445 		memset(rsm, 0, sizeof(struct bbr_sendmap));
3446 		TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_free, rsm, r_next);
3447 		rsm->r_limit_type = 0;
3448 		bbr->r_ctl.rc_free_cnt++;
3449 		return;
3450 	}
3451 	bbr->r_ctl.rc_num_maps_alloced--;
3452 	uma_zfree(bbr_zone, rsm);
3453 }
3454 
3455 /*
3456  * Returns the BDP.
3457  */
3458 static uint64_t
3459 bbr_get_bw_delay_prod(uint64_t rtt, uint64_t bw) {
3460 	/*
3461 	 * Calculate the bytes in flight needed given the bw (in bytes per
3462 	 * second) and the specifyed rtt in useconds. We need to put out the
3463 	 * returned value per RTT to match that rate. Gain will normaly
3464 	 * raise it up from there.
3465 	 *
3466 	 * This should not overflow as long as the bandwidth is below 1
3467 	 * TByte per second (bw < 10**12 = 2**40) and the rtt is smaller
3468 	 * than 1000 seconds (rtt < 10**3 * 10**6 = 10**9 = 2**30).
3469 	 */
3470 	uint64_t usec_per_sec;
3471 
3472 	usec_per_sec = USECS_IN_SECOND;
3473 	return ((rtt * bw) / usec_per_sec);
3474 }
3475 
3476 /*
3477  * Return the initial cwnd.
3478  */
3479 static uint32_t
3480 bbr_initial_cwnd(struct tcp_bbr *bbr, struct tcpcb *tp)
3481 {
3482 	uint32_t i_cwnd;
3483 
3484 	if (bbr->rc_init_win) {
3485 		i_cwnd = bbr->rc_init_win * tp->t_maxseg;
3486 	} else if (V_tcp_initcwnd_segments)
3487 		i_cwnd = min((V_tcp_initcwnd_segments * tp->t_maxseg),
3488 		    max(2 * tp->t_maxseg, 14600));
3489 	else if (V_tcp_do_rfc3390)
3490 		i_cwnd = min(4 * tp->t_maxseg,
3491 		    max(2 * tp->t_maxseg, 4380));
3492 	else {
3493 		/* Per RFC5681 Section 3.1 */
3494 		if (tp->t_maxseg > 2190)
3495 			i_cwnd = 2 * tp->t_maxseg;
3496 		else if (tp->t_maxseg > 1095)
3497 			i_cwnd = 3 * tp->t_maxseg;
3498 		else
3499 			i_cwnd = 4 * tp->t_maxseg;
3500 	}
3501 	return (i_cwnd);
3502 }
3503 
3504 /*
3505  * Given a specified gain, return the target
3506  * cwnd based on that gain.
3507  */
3508 static uint32_t
3509 bbr_get_raw_target_cwnd(struct tcp_bbr *bbr, uint32_t gain, uint64_t bw)
3510 {
3511 	uint64_t bdp, rtt;
3512 	uint32_t cwnd;
3513 
3514 	if ((get_filter_value_small(&bbr->r_ctl.rc_rttprop) == 0xffffffff) ||
3515 	    (bbr_get_full_bw(bbr) == 0)) {
3516 		/* No measurements yet */
3517 		return (bbr_initial_cwnd(bbr, bbr->rc_tp));
3518 	}
3519 	/*
3520 	 * Get bytes per RTT needed (rttProp is normally in
3521 	 * bbr_cwndtarget_rtt_touse)
3522 	 */
3523 	rtt = bbr_get_rtt(bbr, bbr_cwndtarget_rtt_touse);
3524 	/* Get the bdp from the two values */
3525 	bdp = bbr_get_bw_delay_prod(rtt, bw);
3526 	/* Now apply the gain */
3527 	cwnd = (uint32_t)(((bdp * ((uint64_t)gain)) + (uint64_t)(BBR_UNIT - 1)) / ((uint64_t)BBR_UNIT));
3528 
3529 	return (cwnd);
3530 }
3531 
3532 static uint32_t
3533 bbr_get_target_cwnd(struct tcp_bbr *bbr, uint64_t bw, uint32_t gain)
3534 {
3535 	uint32_t cwnd, mss;
3536 
3537 	mss = min((bbr->rc_tp->t_maxseg - bbr->rc_last_options), bbr->r_ctl.rc_pace_max_segs);
3538 	/* Get the base cwnd with gain rounded to a mss */
3539 	cwnd = roundup(bbr_get_raw_target_cwnd(bbr, bw, gain), mss);
3540 	/*
3541 	 * Add in N (2 default since we do not have a
3542 	 * fq layer to trap packets in) quanta's per the I-D
3543 	 * section 4.2.3.2 quanta adjust.
3544 	 */
3545 	cwnd += (bbr_quanta * bbr->r_ctl.rc_pace_max_segs);
3546 	if (bbr->rc_use_google) {
3547 		if((bbr->rc_bbr_state == BBR_STATE_PROBE_BW) &&
3548 		   (bbr_state_val(bbr) == BBR_SUB_GAIN)) {
3549 			/*
3550 			 * The linux implementation adds
3551 			 * an extra 2 x mss in gain cycle which
3552 			 * is documented no-where except in the code.
3553 			 * so we add more for Neal undocumented feature
3554 			 */
3555 			cwnd += 2 * mss;
3556 		}
3557  		if ((cwnd / mss) & 0x1) {
3558 			/* Round up for odd num mss */
3559 			cwnd += mss;
3560 		}
3561 	}
3562 	/* Are we below the min cwnd? */
3563 	if (cwnd < get_min_cwnd(bbr))
3564 		return (get_min_cwnd(bbr));
3565 	return (cwnd);
3566 }
3567 
3568 static uint16_t
3569 bbr_gain_adjust(struct tcp_bbr *bbr, uint16_t gain)
3570 {
3571 	if (gain < 1)
3572 		gain = 1;
3573 	return (gain);
3574 }
3575 
3576 static uint32_t
3577 bbr_get_header_oh(struct tcp_bbr *bbr)
3578 {
3579 	int seg_oh;
3580 
3581 	seg_oh = 0;
3582 	if (bbr->r_ctl.rc_inc_tcp_oh) {
3583 		/* Do we include TCP overhead? */
3584 		seg_oh = (bbr->rc_last_options + sizeof(struct tcphdr));
3585 	}
3586 	if (bbr->r_ctl.rc_inc_ip_oh) {
3587 		/* Do we include IP overhead? */
3588 #ifdef INET6
3589 		if (bbr->r_is_v6)
3590 			seg_oh += sizeof(struct ip6_hdr);
3591 		else
3592 #endif
3593 #ifdef INET
3594 			seg_oh += sizeof(struct ip);
3595 #endif
3596 	}
3597 	if (bbr->r_ctl.rc_inc_enet_oh) {
3598 		/* Do we include the ethernet overhead?  */
3599 		seg_oh += sizeof(struct ether_header);
3600 	}
3601 	return(seg_oh);
3602 }
3603 
3604 
3605 static uint32_t
3606 bbr_get_pacing_length(struct tcp_bbr *bbr, uint16_t gain, uint32_t useconds_time, uint64_t bw)
3607 {
3608 	uint64_t divor, res, tim;
3609 
3610 	if (useconds_time == 0)
3611 		return (0);
3612 	gain = bbr_gain_adjust(bbr, gain);
3613 	divor = (uint64_t)USECS_IN_SECOND * (uint64_t)BBR_UNIT;
3614 	tim = useconds_time;
3615 	res = (tim * bw * gain) / divor;
3616 	if (res == 0)
3617 		res = 1;
3618 	return ((uint32_t)res);
3619 }
3620 
3621 /*
3622  * Given a gain and a length return the delay in useconds that
3623  * should be used to evenly space out packets
3624  * on the connection (based on the gain factor).
3625  */
3626 static uint32_t
3627 bbr_get_pacing_delay(struct tcp_bbr *bbr, uint16_t gain, int32_t len, uint32_t cts, int nolog)
3628 {
3629 	uint64_t bw, lentim, res;
3630 	uint32_t usecs, srtt, over = 0;
3631 	uint32_t seg_oh, num_segs, maxseg;
3632 
3633 	if (len == 0)
3634 		return (0);
3635 
3636 	maxseg = bbr->rc_tp->t_maxseg - bbr->rc_last_options;
3637 	num_segs = (len + maxseg - 1) / maxseg;
3638 	if (bbr->rc_use_google == 0) {
3639 		seg_oh = bbr_get_header_oh(bbr);
3640 		len += (num_segs * seg_oh);
3641 	}
3642 	gain = bbr_gain_adjust(bbr, gain);
3643 	bw = bbr_get_bw(bbr);
3644 	if (bbr->rc_use_google) {
3645 		uint64_t cbw;
3646 
3647 		/*
3648 		 * Reduce the b/w by the google discount
3649 		 * factor 10 = 1%.
3650 		 */
3651 		cbw = bw *  (uint64_t)(1000 - bbr->r_ctl.bbr_google_discount);
3652 		cbw /= (uint64_t)1000;
3653 		/* We don't apply a discount if it results in 0 */
3654 		if (cbw > 0)
3655 			bw = cbw;
3656 	}
3657 	lentim = ((uint64_t)len *
3658 		  (uint64_t)USECS_IN_SECOND *
3659 		  (uint64_t)BBR_UNIT);
3660 	res = lentim / ((uint64_t)gain * bw);
3661 	if (res == 0)
3662 		res = 1;
3663 	usecs = (uint32_t)res;
3664 	srtt = bbr_get_rtt(bbr, BBR_SRTT);
3665 	if (bbr_hptsi_max_mul && bbr_hptsi_max_div &&
3666 	    (bbr->rc_use_google == 0) &&
3667 	    (usecs > ((srtt * bbr_hptsi_max_mul) / bbr_hptsi_max_div))) {
3668 		/*
3669 		 * We cannot let the delay be more than 1/2 the srtt time.
3670 		 * Otherwise we cannot pace out or send properly.
3671 		 */
3672 		over = usecs = (srtt * bbr_hptsi_max_mul) / bbr_hptsi_max_div;
3673 		BBR_STAT_INC(bbr_hpts_min_time);
3674 	}
3675 	if (!nolog)
3676 		bbr_log_pacing_delay_calc(bbr, gain, len, cts, usecs, bw, over, 1);
3677 	return (usecs);
3678 }
3679 
3680 static void
3681 bbr_ack_received(struct tcpcb *tp, struct tcp_bbr *bbr, struct tcphdr *th, uint32_t bytes_this_ack,
3682 		 uint32_t sack_changed, uint32_t prev_acked, int32_t line, uint32_t losses)
3683 {
3684 	INP_WLOCK_ASSERT(tp->t_inpcb);
3685 	uint64_t bw;
3686 	uint32_t cwnd, target_cwnd, saved_bytes, maxseg;
3687 	int32_t meth;
3688 
3689 #ifdef STATS
3690 	if ((tp->t_flags & TF_GPUTINPROG) &&
3691 	    SEQ_GEQ(th->th_ack, tp->gput_ack)) {
3692 		/*
3693 		 * Strech acks and compressed acks will cause this to
3694 		 * oscillate but we are doing it the same way as the main
3695 		 * stack so it will be compariable (though possibly not
3696 		 * ideal).
3697 		 */
3698 		int32_t cgput;
3699 		int64_t gput, time_stamp;
3700 
3701 		gput = (int64_t) (th->th_ack - tp->gput_seq) * 8;
3702 		time_stamp = max(1, ((bbr->r_ctl.rc_rcvtime - tp->gput_ts) / 1000));
3703 		cgput = gput / time_stamp;
3704 		stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_GPUT,
3705 					 cgput);
3706 		if (tp->t_stats_gput_prev > 0)
3707 			stats_voi_update_abs_s32(tp->t_stats,
3708 						 VOI_TCP_GPUT_ND,
3709 						 ((gput - tp->t_stats_gput_prev) * 100) /
3710 						 tp->t_stats_gput_prev);
3711 		tp->t_flags &= ~TF_GPUTINPROG;
3712 		tp->t_stats_gput_prev = cgput;
3713 	}
3714 #endif
3715 	if ((bbr->rc_bbr_state == BBR_STATE_PROBE_RTT) &&
3716 	    ((bbr->r_ctl.bbr_rttprobe_gain_val == 0) || bbr->rc_use_google)) {
3717 		/* We don't change anything in probe-rtt */
3718 		return;
3719 	}
3720 	maxseg = tp->t_maxseg - bbr->rc_last_options;
3721 	saved_bytes = bytes_this_ack;
3722 	bytes_this_ack += sack_changed;
3723 	if (bytes_this_ack > prev_acked) {
3724 		bytes_this_ack -= prev_acked;
3725 		/*
3726 		 * A byte ack'd gives us a full mss
3727 		 * to be like linux i.e. they count packets.
3728 		 */
3729 		if ((bytes_this_ack < maxseg) && bbr->rc_use_google)
3730 			bytes_this_ack = maxseg;
3731 	} else {
3732 		/* Unlikely */
3733 		bytes_this_ack = 0;
3734 	}
3735 	cwnd = tp->snd_cwnd;
3736 	bw = get_filter_value(&bbr->r_ctl.rc_delrate);
3737 	if (bw)
3738 		target_cwnd = bbr_get_target_cwnd(bbr,
3739 						  bw,
3740 						  (uint32_t)bbr->r_ctl.rc_bbr_cwnd_gain);
3741 	else
3742 		target_cwnd = bbr_initial_cwnd(bbr, bbr->rc_tp);
3743 	if (IN_RECOVERY(tp->t_flags) &&
3744 	    (bbr->bbr_prev_in_rec == 0)) {
3745 		/*
3746 		 * We are entering recovery and
3747 		 * thus packet conservation.
3748 		 */
3749 		bbr->pkt_conservation = 1;
3750 		bbr->r_ctl.rc_recovery_start = bbr->r_ctl.rc_rcvtime;
3751 		cwnd = ctf_flight_size(tp,
3752 				       (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes)) +
3753 			bytes_this_ack;
3754 	}
3755 	if (IN_RECOVERY(tp->t_flags)) {
3756 		uint32_t flight;
3757 
3758 		bbr->bbr_prev_in_rec = 1;
3759 		if (cwnd > losses) {
3760 			cwnd -= losses;
3761 			if (cwnd < maxseg)
3762 				cwnd = maxseg;
3763 		} else
3764 			cwnd = maxseg;
3765 		flight = ctf_flight_size(tp,
3766 					 (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
3767 		bbr_log_type_cwndupd(bbr, flight, 0,
3768 				     losses, 10, 0, 0, line);
3769 		if (bbr->pkt_conservation) {
3770 			uint32_t time_in;
3771 
3772 			if (TSTMP_GEQ(bbr->r_ctl.rc_rcvtime, bbr->r_ctl.rc_recovery_start))
3773 				time_in = bbr->r_ctl.rc_rcvtime - bbr->r_ctl.rc_recovery_start;
3774 			else
3775 				time_in = 0;
3776 
3777 			if (time_in >= bbr_get_rtt(bbr, BBR_RTT_PROP)) {
3778 				/* Clear packet conservation after an rttProp */
3779 				bbr->pkt_conservation = 0;
3780 			} else {
3781 				if ((flight + bytes_this_ack) > cwnd)
3782 					cwnd = flight + bytes_this_ack;
3783 				if (cwnd < get_min_cwnd(bbr))
3784 					cwnd = get_min_cwnd(bbr);
3785 				tp->snd_cwnd = cwnd;
3786 				bbr_log_type_cwndupd(bbr, saved_bytes, sack_changed,
3787 						     prev_acked, 1, target_cwnd, th->th_ack, line);
3788 				return;
3789 			}
3790 		}
3791 	} else
3792 		bbr->bbr_prev_in_rec = 0;
3793 	if ((bbr->rc_use_google == 0) && bbr->r_ctl.restrict_growth) {
3794 		bbr->r_ctl.restrict_growth--;
3795 		if (bytes_this_ack > maxseg)
3796 			bytes_this_ack = maxseg;
3797 	}
3798 	if (bbr->rc_filled_pipe) {
3799 		/*
3800 		 * Here we have exited startup and filled the pipe. We will
3801 		 * thus allow the cwnd to shrink to the target. We hit here
3802 		 * mostly.
3803 		 */
3804 		uint32_t s_cwnd;
3805 
3806 		meth = 2;
3807 		s_cwnd = min((cwnd + bytes_this_ack), target_cwnd);
3808 		if (s_cwnd > cwnd)
3809 			cwnd = s_cwnd;
3810 		else if (bbr_cwnd_may_shrink || bbr->rc_use_google || bbr->rc_no_pacing)
3811 			cwnd = s_cwnd;
3812 	} else {
3813 		/*
3814 		 * Here we are still in startup, we increase cwnd by what
3815 		 * has been acked.
3816 		 */
3817 		if ((cwnd < target_cwnd) ||
3818 		    (bbr->rc_past_init_win == 0)) {
3819 			meth = 3;
3820 			cwnd += bytes_this_ack;
3821 		} else {
3822 			/*
3823 			 * Method 4 means we are at target so no gain in
3824 			 * startup and past the initial window.
3825 			 */
3826 			meth = 4;
3827 		}
3828 	}
3829 	tp->snd_cwnd = max(cwnd, get_min_cwnd(bbr));
3830 	bbr_log_type_cwndupd(bbr, saved_bytes, sack_changed, prev_acked, meth, target_cwnd, th->th_ack, line);
3831 }
3832 
3833 static void
3834 tcp_bbr_partialack(struct tcpcb *tp)
3835 {
3836 	struct tcp_bbr *bbr;
3837 
3838 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
3839 	INP_WLOCK_ASSERT(tp->t_inpcb);
3840 	if (ctf_flight_size(tp,
3841 		(bbr->r_ctl.rc_sacked  + bbr->r_ctl.rc_lost_bytes)) <=
3842 	    tp->snd_cwnd) {
3843 		bbr->r_wanted_output = 1;
3844 	}
3845 }
3846 
3847 static void
3848 bbr_post_recovery(struct tcpcb *tp)
3849 {
3850 	struct tcp_bbr *bbr;
3851 	uint32_t  flight;
3852 
3853 	INP_WLOCK_ASSERT(tp->t_inpcb);
3854 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
3855 	/*
3856 	 * Here we just exit recovery.
3857 	 */
3858 	EXIT_RECOVERY(tp->t_flags);
3859 	/* Lock in our b/w reduction for the specified number of pkt-epochs */
3860 	bbr->r_recovery_bw = 0;
3861 	tp->snd_recover = tp->snd_una;
3862 	tcp_bbr_tso_size_check(bbr, bbr->r_ctl.rc_rcvtime);
3863 	bbr->pkt_conservation = 0;
3864 	if (bbr->rc_use_google == 0) {
3865 		/*
3866 		 * For non-google mode lets
3867 		 * go ahead and make sure we clear
3868 		 * the recovery state so if we
3869 		 * bounce back in to recovery we
3870 		 * will do PC.
3871 		 */
3872 		bbr->bbr_prev_in_rec = 0;
3873 	}
3874 	bbr_log_type_exit_rec(bbr);
3875 	if (bbr->rc_bbr_state != BBR_STATE_PROBE_RTT) {
3876 		tp->snd_cwnd = max(tp->snd_cwnd, bbr->r_ctl.rc_cwnd_on_ent);
3877 		bbr_log_type_cwndupd(bbr, 0, 0, 0, 15, 0, 0, __LINE__);
3878 	} else {
3879 		/* For probe-rtt case lets fix up its saved_cwnd */
3880 		if (bbr->r_ctl.rc_saved_cwnd < bbr->r_ctl.rc_cwnd_on_ent) {
3881 			bbr->r_ctl.rc_saved_cwnd = bbr->r_ctl.rc_cwnd_on_ent;
3882 			bbr_log_type_cwndupd(bbr, 0, 0, 0, 16, 0, 0, __LINE__);
3883 		}
3884 	}
3885 	flight = ctf_flight_size(tp,
3886 		     (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
3887 	if ((bbr->rc_use_google == 0) &&
3888 	    bbr_do_red) {
3889 		uint64_t val, lr2use;
3890 		uint32_t maxseg, newcwnd, acks_inflight, ratio, cwnd;
3891 		uint32_t *cwnd_p;
3892 
3893 		if (bbr_get_rtt(bbr, BBR_SRTT)) {
3894 			val = ((uint64_t)bbr_get_rtt(bbr, BBR_RTT_PROP) * (uint64_t)1000);
3895 			val /= bbr_get_rtt(bbr, BBR_SRTT);
3896 			ratio = (uint32_t)val;
3897 		} else
3898 			ratio = 1000;
3899 
3900 		bbr_log_type_cwndupd(bbr, bbr_red_mul, bbr_red_div,
3901 				     bbr->r_ctl.recovery_lr, 21,
3902 				     ratio,
3903 				     bbr->r_ctl.rc_red_cwnd_pe,
3904 				     __LINE__);
3905 		if ((ratio < bbr_do_red) || (bbr_do_red == 0))
3906 			goto done;
3907 		if (((bbr->rc_bbr_state == BBR_STATE_PROBE_RTT) &&
3908 		     bbr_prtt_slam_cwnd) ||
3909 		    (bbr_sub_drain_slam_cwnd &&
3910 		     (bbr->rc_bbr_state == BBR_STATE_PROBE_BW) &&
3911 		     bbr->rc_hit_state_1 &&
3912 		     (bbr_state_val(bbr) == BBR_SUB_DRAIN)) ||
3913 		    ((bbr->rc_bbr_state == BBR_STATE_DRAIN) &&
3914 		     bbr_slam_cwnd_in_main_drain)) {
3915 			/*
3916 			 * Here we must poke at the saved cwnd
3917 			 * as well as the cwnd.
3918 			 */
3919 			cwnd = bbr->r_ctl.rc_saved_cwnd;
3920 			cwnd_p = &bbr->r_ctl.rc_saved_cwnd;
3921 		} else {
3922  			cwnd = tp->snd_cwnd;
3923 			cwnd_p = &tp->snd_cwnd;
3924 		}
3925 		maxseg = tp->t_maxseg - bbr->rc_last_options;
3926 		/* Add the overall lr with the recovery lr */
3927 		if (bbr->r_ctl.rc_lost == 0)
3928 			lr2use = 0;
3929 		else if (bbr->r_ctl.rc_delivered == 0)
3930 			lr2use = 1000;
3931 		else {
3932 			lr2use = bbr->r_ctl.rc_lost * 1000;
3933 			lr2use /= bbr->r_ctl.rc_delivered;
3934 		}
3935 		lr2use += bbr->r_ctl.recovery_lr;
3936 		acks_inflight = (flight / (maxseg * 2));
3937 		if (bbr_red_scale) {
3938 			lr2use *= bbr_get_rtt(bbr, BBR_SRTT);
3939 			lr2use /= bbr_red_scale;
3940 			if ((bbr_red_growth_restrict) &&
3941 			    ((bbr_get_rtt(bbr, BBR_SRTT)/bbr_red_scale) > 1))
3942 			    bbr->r_ctl.restrict_growth += acks_inflight;
3943 		}
3944 		if (lr2use) {
3945 			val = (uint64_t)cwnd * lr2use;
3946 			val /= 1000;
3947 			if (cwnd > val)
3948 				newcwnd = roundup((cwnd - val), maxseg);
3949 			else
3950 				newcwnd = maxseg;
3951 		} else {
3952 			val = (uint64_t)cwnd * (uint64_t)bbr_red_mul;
3953 			val /= (uint64_t)bbr_red_div;
3954 			newcwnd = roundup((uint32_t)val, maxseg);
3955 		}
3956 		/* with standard delayed acks how many acks can I expect? */
3957 		if (bbr_drop_limit == 0) {
3958 			/*
3959 			 * Anticpate how much we will
3960 			 * raise the cwnd based on the acks.
3961 			 */
3962 			if ((newcwnd + (acks_inflight * maxseg)) < get_min_cwnd(bbr)) {
3963 				/* We do enforce the min (with the acks) */
3964 				newcwnd = (get_min_cwnd(bbr) - acks_inflight);
3965 			}
3966 		} else {
3967 			/*
3968 			 * A strict drop limit of N is is inplace
3969 			 */
3970 			if (newcwnd < (bbr_drop_limit * maxseg)) {
3971 				newcwnd = bbr_drop_limit * maxseg;
3972 			}
3973 		}
3974 		/* For the next N acks do we restrict the growth */
3975 		*cwnd_p = newcwnd;
3976 		if (tp->snd_cwnd > newcwnd)
3977 			tp->snd_cwnd = newcwnd;
3978 		bbr_log_type_cwndupd(bbr, bbr_red_mul, bbr_red_div, val, 22,
3979 				     (uint32_t)lr2use,
3980 				     bbr_get_rtt(bbr, BBR_SRTT), __LINE__);
3981 		bbr->r_ctl.rc_red_cwnd_pe = bbr->r_ctl.rc_pkt_epoch;
3982 	}
3983 done:
3984 	bbr->r_ctl.recovery_lr = 0;
3985 	if (flight <= tp->snd_cwnd) {
3986 		bbr->r_wanted_output = 1;
3987 	}
3988 	tcp_bbr_tso_size_check(bbr, bbr->r_ctl.rc_rcvtime);
3989 }
3990 
3991 static void
3992 bbr_setup_red_bw(struct tcp_bbr *bbr, uint32_t cts)
3993 {
3994 	bbr->r_ctl.red_bw = get_filter_value(&bbr->r_ctl.rc_delrate);
3995 	/* Limit the drop in b/w to 1/2 our current filter. */
3996 	if (bbr->r_ctl.red_bw > bbr->r_ctl.rc_bbr_cur_del_rate)
3997 		bbr->r_ctl.red_bw = bbr->r_ctl.rc_bbr_cur_del_rate;
3998 	if (bbr->r_ctl.red_bw < (get_filter_value(&bbr->r_ctl.rc_delrate) / 2))
3999 		bbr->r_ctl.red_bw = get_filter_value(&bbr->r_ctl.rc_delrate) / 2;
4000 	tcp_bbr_tso_size_check(bbr, cts);
4001 }
4002 
4003 static void
4004 bbr_cong_signal(struct tcpcb *tp, struct tcphdr *th, uint32_t type, struct bbr_sendmap *rsm)
4005 {
4006 	struct tcp_bbr *bbr;
4007 
4008 	INP_WLOCK_ASSERT(tp->t_inpcb);
4009 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
4010 	switch (type) {
4011 	case CC_NDUPACK:
4012 		if (!IN_RECOVERY(tp->t_flags)) {
4013 			tp->snd_recover = tp->snd_max;
4014 			/* Start a new epoch */
4015 			bbr_set_pktepoch(bbr, bbr->r_ctl.rc_rcvtime, __LINE__);
4016 			if (bbr->rc_lt_is_sampling || bbr->rc_lt_use_bw) {
4017 				/*
4018 				 * Move forward the lt epoch
4019 				 * so it won't count the truncated
4020 				 * epoch.
4021 				 */
4022 				bbr->r_ctl.rc_lt_epoch++;
4023 			}
4024 			if (bbr->rc_bbr_state == BBR_STATE_STARTUP) {
4025 				/*
4026 				 * Just like the policer detection code
4027 				 * if we are in startup we must push
4028 				 * forward the last startup epoch
4029 				 * to hide the truncated PE.
4030 				 */
4031 				bbr->r_ctl.rc_bbr_last_startup_epoch++;
4032 			}
4033 			bbr->r_ctl.rc_cwnd_on_ent = tp->snd_cwnd;
4034 			ENTER_RECOVERY(tp->t_flags);
4035 			bbr->rc_tlp_rtx_out = 0;
4036 			bbr->r_ctl.recovery_lr = bbr->r_ctl.rc_pkt_epoch_loss_rate;
4037 			tcp_bbr_tso_size_check(bbr, bbr->r_ctl.rc_rcvtime);
4038 			if (bbr->rc_inp->inp_in_hpts &&
4039 			    ((bbr->r_ctl.rc_hpts_flags & PACE_TMR_RACK) == 0)) {
4040 				/*
4041 				 * When we enter recovery, we need to restart
4042 				 * any timers. This may mean we gain an agg
4043 				 * early, which will be made up for at the last
4044 				 * rxt out.
4045 				 */
4046 				bbr->rc_timer_first = 1;
4047 				bbr_timer_cancel(bbr, __LINE__, bbr->r_ctl.rc_rcvtime);
4048 			}
4049 			/*
4050 			 * Calculate a new cwnd based on to the current
4051 			 * delivery rate with no gain. We get the bdp
4052 			 * without gaining it up like we normally would and
4053 			 * we use the last cur_del_rate.
4054 			 */
4055 			if ((bbr->rc_use_google == 0) &&
4056 			    (bbr->r_ctl.bbr_rttprobe_gain_val ||
4057 			     (bbr->rc_bbr_state != BBR_STATE_PROBE_RTT))) {
4058 				tp->snd_cwnd = ctf_flight_size(tp,
4059 					           (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes)) +
4060 					(tp->t_maxseg - bbr->rc_last_options);
4061 				if (tp->snd_cwnd < get_min_cwnd(bbr)) {
4062 					/* We always gate to min cwnd */
4063 					tp->snd_cwnd = get_min_cwnd(bbr);
4064 				}
4065 				bbr_log_type_cwndupd(bbr, 0, 0, 0, 14, 0, 0, __LINE__);
4066 			}
4067 			bbr_log_type_enter_rec(bbr, rsm->r_start);
4068 		}
4069 		break;
4070 	case CC_RTO_ERR:
4071 		KMOD_TCPSTAT_INC(tcps_sndrexmitbad);
4072 		/* RTO was unnecessary, so reset everything. */
4073 		bbr_reset_lt_bw_sampling(bbr, bbr->r_ctl.rc_rcvtime);
4074 		if (bbr->rc_bbr_state != BBR_STATE_PROBE_RTT) {
4075 			tp->snd_cwnd = tp->snd_cwnd_prev;
4076 			tp->snd_ssthresh = tp->snd_ssthresh_prev;
4077 			tp->snd_recover = tp->snd_recover_prev;
4078 			tp->snd_cwnd = max(tp->snd_cwnd, bbr->r_ctl.rc_cwnd_on_ent);
4079 			bbr_log_type_cwndupd(bbr, 0, 0, 0, 13, 0, 0, __LINE__);
4080 		}
4081 		tp->t_badrxtwin = 0;
4082 		break;
4083 	}
4084 }
4085 
4086 /*
4087  * Indicate whether this ack should be delayed.  We can delay the ack if
4088  * following conditions are met:
4089  *	- There is no delayed ack timer in progress.
4090  *	- Our last ack wasn't a 0-sized window. We never want to delay
4091  *	  the ack that opens up a 0-sized window.
4092  *	- LRO wasn't used for this segment. We make sure by checking that the
4093  *	  segment size is not larger than the MSS.
4094  *	- Delayed acks are enabled or this is a half-synchronized T/TCP
4095  *	  connection.
4096  *	- The data being acked is less than a full segment (a stretch ack
4097  *        of more than a segment we should ack.
4098  *      - nsegs is 1 (if its more than that we received more than 1 ack).
4099  */
4100 #define DELAY_ACK(tp, bbr, nsegs)				\
4101 	(((tp->t_flags & TF_RXWIN0SENT) == 0) &&		\
4102 	 ((bbr->bbr_segs_rcvd + nsegs) < tp->t_delayed_ack) &&	\
4103 	 (tp->t_delayed_ack || (tp->t_flags & TF_NEEDSYN)))
4104 
4105 /*
4106  * Return the lowest RSM in the map of
4107  * packets still in flight that is not acked.
4108  * This should normally find on the first one
4109  * since we remove packets from the send
4110  * map after they are marked ACKED.
4111  */
4112 static struct bbr_sendmap *
4113 bbr_find_lowest_rsm(struct tcp_bbr *bbr)
4114 {
4115 	struct bbr_sendmap *rsm;
4116 
4117 	/*
4118 	 * Walk the time-order transmitted list looking for an rsm that is
4119 	 * not acked. This will be the one that was sent the longest time
4120 	 * ago that is still outstanding.
4121 	 */
4122 	TAILQ_FOREACH(rsm, &bbr->r_ctl.rc_tmap, r_tnext) {
4123 		if (rsm->r_flags & BBR_ACKED) {
4124 			continue;
4125 		}
4126 		goto finish;
4127 	}
4128 finish:
4129 	return (rsm);
4130 }
4131 
4132 static struct bbr_sendmap *
4133 bbr_find_high_nonack(struct tcp_bbr *bbr, struct bbr_sendmap *rsm)
4134 {
4135 	struct bbr_sendmap *prsm;
4136 
4137 	/*
4138 	 * Walk the sequence order list backward until we hit and arrive at
4139 	 * the highest seq not acked. In theory when this is called it
4140 	 * should be the last segment (which it was not).
4141 	 */
4142 	prsm = rsm;
4143 	TAILQ_FOREACH_REVERSE_FROM(prsm, &bbr->r_ctl.rc_map, bbr_head, r_next) {
4144 		if (prsm->r_flags & (BBR_ACKED | BBR_HAS_FIN)) {
4145 			continue;
4146 		}
4147 		return (prsm);
4148 	}
4149 	return (NULL);
4150 }
4151 
4152 /*
4153  * Returns to the caller the number of microseconds that
4154  * the packet can be outstanding before we think we
4155  * should have had an ack returned.
4156  */
4157 static uint32_t
4158 bbr_calc_thresh_rack(struct tcp_bbr *bbr, uint32_t srtt, uint32_t cts, struct bbr_sendmap *rsm)
4159 {
4160 	/*
4161 	 * lro is the flag we use to determine if we have seen reordering.
4162 	 * If it gets set we have seen reordering. The reorder logic either
4163 	 * works in one of two ways:
4164 	 *
4165 	 * If reorder-fade is configured, then we track the last time we saw
4166 	 * re-ordering occur. If we reach the point where enough time as
4167 	 * passed we no longer consider reordering has occuring.
4168 	 *
4169 	 * Or if reorder-face is 0, then once we see reordering we consider
4170 	 * the connection to alway be subject to reordering and just set lro
4171 	 * to 1.
4172 	 *
4173 	 * In the end if lro is non-zero we add the extra time for
4174 	 * reordering in.
4175 	 */
4176 	int32_t lro;
4177 	uint32_t thresh, t_rxtcur;
4178 
4179 	if (srtt == 0)
4180 		srtt = 1;
4181 	if (bbr->r_ctl.rc_reorder_ts) {
4182 		if (bbr->r_ctl.rc_reorder_fade) {
4183 			if (SEQ_GEQ(cts, bbr->r_ctl.rc_reorder_ts)) {
4184 				lro = cts - bbr->r_ctl.rc_reorder_ts;
4185 				if (lro == 0) {
4186 					/*
4187 					 * No time as passed since the last
4188 					 * reorder, mark it as reordering.
4189 					 */
4190 					lro = 1;
4191 				}
4192 			} else {
4193 				/* Negative time? */
4194 				lro = 0;
4195 			}
4196 			if (lro > bbr->r_ctl.rc_reorder_fade) {
4197 				/* Turn off reordering seen too */
4198 				bbr->r_ctl.rc_reorder_ts = 0;
4199 				lro = 0;
4200 			}
4201 		} else {
4202 			/* Reodering does not fade */
4203 			lro = 1;
4204 		}
4205 	} else {
4206 		lro = 0;
4207 	}
4208 	thresh = srtt + bbr->r_ctl.rc_pkt_delay;
4209 	if (lro) {
4210 		/* It must be set, if not you get 1/4 rtt */
4211 		if (bbr->r_ctl.rc_reorder_shift)
4212 			thresh += (srtt >> bbr->r_ctl.rc_reorder_shift);
4213 		else
4214 			thresh += (srtt >> 2);
4215 	} else {
4216 		thresh += 1000;
4217 	}
4218 	/* We don't let the rack timeout be above a RTO */
4219 	if ((bbr->rc_tp)->t_srtt == 0)
4220 		t_rxtcur = BBR_INITIAL_RTO;
4221 	else
4222 		t_rxtcur = TICKS_2_USEC(bbr->rc_tp->t_rxtcur);
4223 	if (thresh > t_rxtcur) {
4224 		thresh = t_rxtcur;
4225 	}
4226 	/* And we don't want it above the RTO max either */
4227 	if (thresh > (((uint32_t)bbr->rc_max_rto_sec) * USECS_IN_SECOND)) {
4228 		thresh = (((uint32_t)bbr->rc_max_rto_sec) * USECS_IN_SECOND);
4229 	}
4230 	bbr_log_thresh_choice(bbr, cts, thresh, lro, srtt, rsm, BBR_TO_FRM_RACK);
4231 	return (thresh);
4232 }
4233 
4234 /*
4235  * Return to the caller the amount of time in mico-seconds
4236  * that should be used for the TLP timer from the last
4237  * send time of this packet.
4238  */
4239 static uint32_t
4240 bbr_calc_thresh_tlp(struct tcpcb *tp, struct tcp_bbr *bbr,
4241     struct bbr_sendmap *rsm, uint32_t srtt,
4242     uint32_t cts)
4243 {
4244 	uint32_t thresh, len, maxseg, t_rxtcur;
4245 	struct bbr_sendmap *prsm;
4246 
4247 	if (srtt == 0)
4248 		srtt = 1;
4249 	if (bbr->rc_tlp_threshold)
4250 		thresh = srtt + (srtt / bbr->rc_tlp_threshold);
4251 	else
4252 		thresh = (srtt * 2);
4253 	maxseg = tp->t_maxseg - bbr->rc_last_options;
4254 	/* Get the previous sent packet, if any  */
4255 	len = rsm->r_end - rsm->r_start;
4256 
4257 	/* 2.1 behavior */
4258 	prsm = TAILQ_PREV(rsm, bbr_head, r_tnext);
4259 	if (prsm && (len <= maxseg)) {
4260 		/*
4261 		 * Two packets outstanding, thresh should be (2*srtt) +
4262 		 * possible inter-packet delay (if any).
4263 		 */
4264 		uint32_t inter_gap = 0;
4265 		int idx, nidx;
4266 
4267 		idx = rsm->r_rtr_cnt - 1;
4268 		nidx = prsm->r_rtr_cnt - 1;
4269 		if (TSTMP_GEQ(rsm->r_tim_lastsent[nidx], prsm->r_tim_lastsent[idx])) {
4270 			/* Yes it was sent later (or at the same time) */
4271 			inter_gap = rsm->r_tim_lastsent[idx] - prsm->r_tim_lastsent[nidx];
4272 		}
4273 		thresh += inter_gap;
4274 	} else if (len <= maxseg) {
4275 		/*
4276 		 * Possibly compensate for delayed-ack.
4277 		 */
4278 		uint32_t alt_thresh;
4279 
4280 		alt_thresh = srtt + (srtt / 2) + bbr_delayed_ack_time;
4281 		if (alt_thresh > thresh)
4282 			thresh = alt_thresh;
4283 	}
4284 	/* Not above the current  RTO */
4285 	if (tp->t_srtt == 0)
4286 		t_rxtcur = BBR_INITIAL_RTO;
4287 	else
4288 		t_rxtcur = TICKS_2_USEC(tp->t_rxtcur);
4289 
4290 	bbr_log_thresh_choice(bbr, cts, thresh, t_rxtcur, srtt, rsm, BBR_TO_FRM_TLP);
4291 	/* Not above an RTO */
4292 	if (thresh > t_rxtcur) {
4293 		thresh = t_rxtcur;
4294 	}
4295 	/* Not above a RTO max */
4296 	if (thresh > (((uint32_t)bbr->rc_max_rto_sec) * USECS_IN_SECOND)) {
4297 		thresh = (((uint32_t)bbr->rc_max_rto_sec) * USECS_IN_SECOND);
4298 	}
4299 	/* And now apply the user TLP min */
4300 	if (thresh < bbr_tlp_min) {
4301 		thresh = bbr_tlp_min;
4302 	}
4303 	return (thresh);
4304 }
4305 
4306 /*
4307  * Return one of three RTTs to use (in microseconds).
4308  */
4309 static __inline uint32_t
4310 bbr_get_rtt(struct tcp_bbr *bbr, int32_t rtt_type)
4311 {
4312 	uint32_t f_rtt;
4313 	uint32_t srtt;
4314 
4315 	f_rtt = get_filter_value_small(&bbr->r_ctl.rc_rttprop);
4316 	if (get_filter_value_small(&bbr->r_ctl.rc_rttprop) == 0xffffffff) {
4317 		/* We have no rtt at all */
4318 		if (bbr->rc_tp->t_srtt == 0)
4319 			f_rtt = BBR_INITIAL_RTO;
4320 		else
4321 			f_rtt = (TICKS_2_USEC(bbr->rc_tp->t_srtt) >> TCP_RTT_SHIFT);
4322 		/*
4323 		 * Since we don't know how good the rtt is apply a
4324 		 * delayed-ack min
4325 		 */
4326 		if (f_rtt < bbr_delayed_ack_time) {
4327 			f_rtt = bbr_delayed_ack_time;
4328 		}
4329 	}
4330 	/* Take the filter version or last measured pkt-rtt */
4331 	if (rtt_type == BBR_RTT_PROP) {
4332 		srtt = f_rtt;
4333 	} else if (rtt_type == BBR_RTT_PKTRTT) {
4334 		if (bbr->r_ctl.rc_pkt_epoch_rtt) {
4335 			srtt = bbr->r_ctl.rc_pkt_epoch_rtt;
4336 		} else {
4337 			/* No pkt rtt yet */
4338 			srtt = f_rtt;
4339 		}
4340 	} else if (rtt_type == BBR_RTT_RACK) {
4341 		srtt = bbr->r_ctl.rc_last_rtt;
4342 		/* We need to add in any internal delay for our timer */
4343 		if (bbr->rc_ack_was_delayed)
4344 			srtt += bbr->r_ctl.rc_ack_hdwr_delay;
4345 	} else if (rtt_type == BBR_SRTT) {
4346 		srtt = (TICKS_2_USEC(bbr->rc_tp->t_srtt) >> TCP_RTT_SHIFT);
4347 	} else {
4348 		/* TSNH */
4349 		srtt = f_rtt;
4350 #ifdef BBR_INVARIANTS
4351 		panic("Unknown rtt request type %d", rtt_type);
4352 #endif
4353 	}
4354 	return (srtt);
4355 }
4356 
4357 static int
4358 bbr_is_lost(struct tcp_bbr *bbr, struct bbr_sendmap *rsm, uint32_t cts)
4359 {
4360 	uint32_t thresh;
4361 
4362 
4363 	thresh = bbr_calc_thresh_rack(bbr, bbr_get_rtt(bbr, BBR_RTT_RACK),
4364 				      cts, rsm);
4365 	if ((cts - rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)]) >= thresh) {
4366 		/* It is lost (past time) */
4367 		return (1);
4368 	}
4369 	return (0);
4370 }
4371 
4372 /*
4373  * Return a sendmap if we need to retransmit something.
4374  */
4375 static struct bbr_sendmap *
4376 bbr_check_recovery_mode(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4377 {
4378 	/*
4379 	 * Check to see that we don't need to fall into recovery. We will
4380 	 * need to do so if our oldest transmit is past the time we should
4381 	 * have had an ack.
4382 	 */
4383 
4384 	struct bbr_sendmap *rsm;
4385 	int32_t idx;
4386 
4387 	if (TAILQ_EMPTY(&bbr->r_ctl.rc_map)) {
4388 		/* Nothing outstanding that we know of */
4389 		return (NULL);
4390 	}
4391 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_tmap);
4392 	if (rsm == NULL) {
4393 		/* Nothing in the transmit map */
4394 		return (NULL);
4395 	}
4396 	if (tp->t_flags & TF_SENTFIN) {
4397 		/* Fin restricted, don't find anything once a fin is sent */
4398 		return (NULL);
4399 	}
4400 	if (rsm->r_flags & BBR_ACKED) {
4401 		/*
4402 		 * Ok the first one is acked (this really should not happen
4403 		 * since we remove the from the tmap once they are acked)
4404 		 */
4405 		rsm = bbr_find_lowest_rsm(bbr);
4406 		if (rsm == NULL)
4407 			return (NULL);
4408 	}
4409 	idx = rsm->r_rtr_cnt - 1;
4410 	if (SEQ_LEQ(cts, rsm->r_tim_lastsent[idx])) {
4411 		/* Send timestamp is the same or less? can't be ready */
4412 		return (NULL);
4413 	}
4414 	/* Get our RTT time */
4415 	if (bbr_is_lost(bbr, rsm, cts) &&
4416 	    ((rsm->r_dupack >= DUP_ACK_THRESHOLD) ||
4417 	     (rsm->r_flags & BBR_SACK_PASSED))) {
4418 		if ((rsm->r_flags & BBR_MARKED_LOST) == 0) {
4419 			rsm->r_flags |= BBR_MARKED_LOST;
4420 			bbr->r_ctl.rc_lost += rsm->r_end - rsm->r_start;
4421 			bbr->r_ctl.rc_lost_bytes += rsm->r_end - rsm->r_start;
4422 		}
4423 		bbr_cong_signal(tp, NULL, CC_NDUPACK, rsm);
4424 #ifdef BBR_INVARIANTS
4425 		if ((rsm->r_end - rsm->r_start) == 0)
4426 			panic("tp:%p bbr:%p rsm:%p length is 0?", tp, bbr, rsm);
4427 #endif
4428 		return (rsm);
4429 	}
4430 	return (NULL);
4431 }
4432 
4433 /*
4434  * RACK Timer, here we simply do logging and house keeping.
4435  * the normal bbr_output_wtime() function will call the
4436  * appropriate thing to check if we need to do a RACK retransmit.
4437  * We return 1, saying don't proceed with bbr_output_wtime only
4438  * when all timers have been stopped (destroyed PCB?).
4439  */
4440 static int
4441 bbr_timeout_rack(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4442 {
4443 	/*
4444 	 * This timer simply provides an internal trigger to send out data.
4445 	 * The check_recovery_mode call will see if there are needed
4446 	 * retransmissions, if so we will enter fast-recovery. The output
4447 	 * call may or may not do the same thing depending on sysctl
4448 	 * settings.
4449 	 */
4450 	uint32_t lost;
4451 
4452 	if (bbr->rc_all_timers_stopped) {
4453 		return (1);
4454 	}
4455 	if (TSTMP_LT(cts, bbr->r_ctl.rc_timer_exp)) {
4456 		/* Its not time yet */
4457 		return (0);
4458 	}
4459 	BBR_STAT_INC(bbr_to_tot);
4460 	lost = bbr->r_ctl.rc_lost;
4461 	if (bbr->r_state && (bbr->r_state != tp->t_state))
4462 		bbr_set_state(tp, bbr, 0);
4463 	bbr_log_to_event(bbr, cts, BBR_TO_FRM_RACK);
4464 	if (bbr->r_ctl.rc_resend == NULL) {
4465 		/* Lets do the check here */
4466 		bbr->r_ctl.rc_resend = bbr_check_recovery_mode(tp, bbr, cts);
4467 	}
4468 	if (bbr_policer_call_from_rack_to)
4469 		bbr_lt_bw_sampling(bbr, cts, (bbr->r_ctl.rc_lost > lost));
4470 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_RACK;
4471 	return (0);
4472 }
4473 
4474 static __inline void
4475 bbr_clone_rsm(struct tcp_bbr *bbr, struct bbr_sendmap *nrsm, struct bbr_sendmap *rsm, uint32_t start)
4476 {
4477 	int idx;
4478 
4479 	nrsm->r_start = start;
4480 	nrsm->r_end = rsm->r_end;
4481 	nrsm->r_rtr_cnt = rsm->r_rtr_cnt;
4482 	nrsm->r_flags = rsm->r_flags;
4483 	/* We don't transfer forward the SYN flag */
4484 	nrsm->r_flags &= ~BBR_HAS_SYN;
4485 	/* We move forward the FIN flag, not that this should happen */
4486 	rsm->r_flags &= ~BBR_HAS_FIN;
4487 	nrsm->r_dupack = rsm->r_dupack;
4488 	nrsm->r_rtr_bytes = 0;
4489 	nrsm->r_is_gain = rsm->r_is_gain;
4490 	nrsm->r_is_drain = rsm->r_is_drain;
4491 	nrsm->r_delivered = rsm->r_delivered;
4492 	nrsm->r_ts_valid = rsm->r_ts_valid;
4493 	nrsm->r_del_ack_ts = rsm->r_del_ack_ts;
4494 	nrsm->r_del_time = rsm->r_del_time;
4495 	nrsm->r_app_limited = rsm->r_app_limited;
4496 	nrsm->r_first_sent_time = rsm->r_first_sent_time;
4497 	nrsm->r_flight_at_send = rsm->r_flight_at_send;
4498 	/* We split a piece the lower section looses any just_ret flag. */
4499 	nrsm->r_bbr_state = rsm->r_bbr_state;
4500 	for (idx = 0; idx < nrsm->r_rtr_cnt; idx++) {
4501 		nrsm->r_tim_lastsent[idx] = rsm->r_tim_lastsent[idx];
4502 	}
4503 	rsm->r_end = nrsm->r_start;
4504 	idx = min((bbr->rc_tp->t_maxseg - bbr->rc_last_options), bbr->r_ctl.rc_pace_max_segs);
4505 	idx /= 8;
4506 	/* Check if we got too small */
4507 	if ((rsm->r_is_smallmap == 0) &&
4508 	    ((rsm->r_end - rsm->r_start) <= idx)) {
4509 		bbr->r_ctl.rc_num_small_maps_alloced++;
4510 		rsm->r_is_smallmap = 1;
4511 	}
4512 	/* Check the new one as well */
4513 	if ((nrsm->r_end - nrsm->r_start) <= idx) {
4514 		bbr->r_ctl.rc_num_small_maps_alloced++;
4515 		nrsm->r_is_smallmap = 1;
4516 	}
4517 }
4518 
4519 static int
4520 bbr_sack_mergable(struct bbr_sendmap *at,
4521 		  uint32_t start, uint32_t end)
4522 {
4523 	/*
4524 	 * Given a sack block defined by
4525 	 * start and end, and a current postion
4526 	 * at. Return 1 if either side of at
4527 	 * would show that the block is mergable
4528 	 * to that side. A block to be mergable
4529 	 * must have overlap with the start/end
4530 	 * and be in the SACK'd state.
4531 	 */
4532 	struct bbr_sendmap *l_rsm;
4533 	struct bbr_sendmap *r_rsm;
4534 
4535 	/* first get the either side blocks */
4536 	l_rsm = TAILQ_PREV(at, bbr_head, r_next);
4537 	r_rsm = TAILQ_NEXT(at, r_next);
4538 	if (l_rsm && (l_rsm->r_flags & BBR_ACKED)) {
4539 		/* Potentially mergeable */
4540 		if ((l_rsm->r_end == start) ||
4541 		    (SEQ_LT(start, l_rsm->r_end) &&
4542 		     SEQ_GT(end, l_rsm->r_end))) {
4543 			    /*
4544 			     * map blk   |------|
4545 			     * sack blk         |------|
4546 			     * <or>
4547 			     * map blk   |------|
4548 			     * sack blk      |------|
4549 			     */
4550 			    return (1);
4551 		    }
4552 	}
4553 	if (r_rsm && (r_rsm->r_flags & BBR_ACKED)) {
4554 		/* Potentially mergeable */
4555 		if ((r_rsm->r_start == end) ||
4556 		    (SEQ_LT(start, r_rsm->r_start) &&
4557 		     SEQ_GT(end, r_rsm->r_start))) {
4558 			/*
4559 			 * map blk          |---------|
4560 			 * sack blk    |----|
4561 			 * <or>
4562 			 * map blk          |---------|
4563 			 * sack blk    |-------|
4564 			 */
4565 			return (1);
4566 		}
4567 	}
4568 	return (0);
4569 }
4570 
4571 static struct bbr_sendmap *
4572 bbr_merge_rsm(struct tcp_bbr *bbr,
4573 	      struct bbr_sendmap *l_rsm,
4574 	      struct bbr_sendmap *r_rsm)
4575 {
4576 	/*
4577 	 * We are merging two ack'd RSM's,
4578 	 * the l_rsm is on the left (lower seq
4579 	 * values) and the r_rsm is on the right
4580 	 * (higher seq value). The simplest way
4581 	 * to merge these is to move the right
4582 	 * one into the left. I don't think there
4583 	 * is any reason we need to try to find
4584 	 * the oldest (or last oldest retransmitted).
4585 	 */
4586 	l_rsm->r_end = r_rsm->r_end;
4587 	if (l_rsm->r_dupack < r_rsm->r_dupack)
4588 		l_rsm->r_dupack = r_rsm->r_dupack;
4589 	if (r_rsm->r_rtr_bytes)
4590 		l_rsm->r_rtr_bytes += r_rsm->r_rtr_bytes;
4591 	if (r_rsm->r_in_tmap) {
4592 		/* This really should not happen */
4593 		TAILQ_REMOVE(&bbr->r_ctl.rc_tmap, r_rsm, r_tnext);
4594 	}
4595 	if (r_rsm->r_app_limited)
4596 		l_rsm->r_app_limited = r_rsm->r_app_limited;
4597 	/* Now the flags */
4598 	if (r_rsm->r_flags & BBR_HAS_FIN)
4599 		l_rsm->r_flags |= BBR_HAS_FIN;
4600 	if (r_rsm->r_flags & BBR_TLP)
4601 		l_rsm->r_flags |= BBR_TLP;
4602 	if (r_rsm->r_flags & BBR_RWND_COLLAPSED)
4603 		l_rsm->r_flags |= BBR_RWND_COLLAPSED;
4604 	if (r_rsm->r_flags & BBR_MARKED_LOST) {
4605 		/* This really should not happen */
4606 		bbr->r_ctl.rc_lost_bytes -= r_rsm->r_end - r_rsm->r_start;
4607 	}
4608 	TAILQ_REMOVE(&bbr->r_ctl.rc_map, r_rsm, r_next);
4609 	if ((r_rsm->r_limit_type == 0) && (l_rsm->r_limit_type != 0)) {
4610 		/* Transfer the split limit to the map we free */
4611 		r_rsm->r_limit_type = l_rsm->r_limit_type;
4612 		l_rsm->r_limit_type = 0;
4613 	}
4614 	bbr_free(bbr, r_rsm);
4615 	return(l_rsm);
4616 }
4617 
4618 /*
4619  * TLP Timer, here we simply setup what segment we want to
4620  * have the TLP expire on, the normal bbr_output_wtime() will then
4621  * send it out.
4622  *
4623  * We return 1, saying don't proceed with bbr_output_wtime only
4624  * when all timers have been stopped (destroyed PCB?).
4625  */
4626 static int
4627 bbr_timeout_tlp(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4628 {
4629 	/*
4630 	 * Tail Loss Probe.
4631 	 */
4632 	struct bbr_sendmap *rsm = NULL;
4633 	struct socket *so;
4634 	uint32_t amm;
4635 	uint32_t out, avail;
4636 	uint32_t maxseg;
4637 	int collapsed_win = 0;
4638 
4639 	if (bbr->rc_all_timers_stopped) {
4640 		return (1);
4641 	}
4642 	if (TSTMP_LT(cts, bbr->r_ctl.rc_timer_exp)) {
4643 		/* Its not time yet */
4644 		return (0);
4645 	}
4646 	if (bbr_progress_timeout_check(bbr)) {
4647 		tcp_set_inp_to_drop(bbr->rc_inp, ETIMEDOUT);
4648 		return (1);
4649 	}
4650 	/* Did we somehow get into persists? */
4651 	if (bbr->rc_in_persist) {
4652 		return (0);
4653 	}
4654 	if (bbr->r_state && (bbr->r_state != tp->t_state))
4655 		bbr_set_state(tp, bbr, 0);
4656 	BBR_STAT_INC(bbr_tlp_tot);
4657 	maxseg = tp->t_maxseg - bbr->rc_last_options;
4658 #ifdef KERN_TLS
4659 	if (bbr->rc_inp->inp_socket->so_snd.sb_flags & SB_TLS_IFNET) {
4660 		/*
4661 		 * For hardware TLS we do *not* want to send
4662 		 * new data.
4663 		 */
4664 		goto need_retran;
4665 	}
4666 #endif
4667 	/*
4668 	 * A TLP timer has expired. We have been idle for 2 rtts. So we now
4669 	 * need to figure out how to force a full MSS segment out.
4670 	 */
4671 	so = tp->t_inpcb->inp_socket;
4672 	avail = sbavail(&so->so_snd);
4673 	out = ctf_outstanding(tp);
4674 	if (out > tp->snd_wnd) {
4675 		/* special case, we need a retransmission */
4676 		collapsed_win = 1;
4677 		goto need_retran;
4678 	}
4679 	if (avail > out) {
4680 		/* New data is available */
4681 		amm = avail - out;
4682 		if (amm > maxseg) {
4683 			amm = maxseg;
4684 		} else if ((amm < maxseg) && ((tp->t_flags & TF_NODELAY) == 0)) {
4685 			/* not enough to fill a MTU and no-delay is off */
4686 			goto need_retran;
4687 		}
4688 		/* Set the send-new override */
4689 		if ((out + amm) <= tp->snd_wnd) {
4690 			bbr->rc_tlp_new_data = 1;
4691 		} else {
4692 			goto need_retran;
4693 		}
4694 		bbr->r_ctl.rc_tlp_seg_send_cnt = 0;
4695 		bbr->r_ctl.rc_last_tlp_seq = tp->snd_max;
4696 		bbr->r_ctl.rc_tlp_send = NULL;
4697 		/* cap any slots */
4698 		BBR_STAT_INC(bbr_tlp_newdata);
4699 		goto send;
4700 	}
4701 need_retran:
4702 	/*
4703 	 * Ok we need to arrange the last un-acked segment to be re-sent, or
4704 	 * optionally the first un-acked segment.
4705 	 */
4706 	if (collapsed_win == 0) {
4707 		rsm = TAILQ_LAST_FAST(&bbr->r_ctl.rc_map, bbr_sendmap, r_next);
4708 		if (rsm && (BBR_ACKED | BBR_HAS_FIN)) {
4709 			rsm = bbr_find_high_nonack(bbr, rsm);
4710 		}
4711 		if (rsm == NULL) {
4712 			goto restore;
4713 		}
4714 	} else {
4715 		/*
4716 		 * We must find the last segment
4717 		 * that was acceptable by the client.
4718 		 */
4719 		TAILQ_FOREACH_REVERSE(rsm, &bbr->r_ctl.rc_map, bbr_head, r_next) {
4720 			if ((rsm->r_flags & BBR_RWND_COLLAPSED) == 0) {
4721 				/* Found one */
4722 				break;
4723 			}
4724 		}
4725 		if (rsm == NULL) {
4726 			/* None? if so send the first */
4727 			rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
4728 			if (rsm == NULL)
4729 				goto restore;
4730 		}
4731 	}
4732 	if ((rsm->r_end - rsm->r_start) > maxseg) {
4733 		/*
4734 		 * We need to split this the last segment in two.
4735 		 */
4736 		struct bbr_sendmap *nrsm;
4737 
4738 		nrsm = bbr_alloc_full_limit(bbr);
4739 		if (nrsm == NULL) {
4740 			/*
4741 			 * We can't get memory to split, we can either just
4742 			 * not split it. Or retransmit the whole piece, lets
4743 			 * do the large send (BTLP :-) ).
4744 			 */
4745 			goto go_for_it;
4746 		}
4747 		bbr_clone_rsm(bbr, nrsm, rsm, (rsm->r_end - maxseg));
4748 		TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_map, rsm, nrsm, r_next);
4749 		if (rsm->r_in_tmap) {
4750 			TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
4751 			nrsm->r_in_tmap = 1;
4752 		}
4753 		rsm->r_flags &= (~BBR_HAS_FIN);
4754 		rsm = nrsm;
4755 	}
4756 go_for_it:
4757 	bbr->r_ctl.rc_tlp_send = rsm;
4758 	bbr->rc_tlp_rtx_out = 1;
4759 	if (rsm->r_start == bbr->r_ctl.rc_last_tlp_seq) {
4760 		bbr->r_ctl.rc_tlp_seg_send_cnt++;
4761 		tp->t_rxtshift++;
4762 	} else {
4763 		bbr->r_ctl.rc_last_tlp_seq = rsm->r_start;
4764 		bbr->r_ctl.rc_tlp_seg_send_cnt = 1;
4765 	}
4766 send:
4767 	if (bbr->r_ctl.rc_tlp_seg_send_cnt > bbr_tlp_max_resend) {
4768 		/*
4769 		 * Can't [re]/transmit a segment we have retranmitted the
4770 		 * max times. We need the retransmit timer to take over.
4771 		 */
4772 restore:
4773 		bbr->rc_tlp_new_data = 0;
4774 		bbr->r_ctl.rc_tlp_send = NULL;
4775 		if (rsm)
4776 			rsm->r_flags &= ~BBR_TLP;
4777 		BBR_STAT_INC(bbr_tlp_retran_fail);
4778 		return (0);
4779 	} else if (rsm) {
4780 		rsm->r_flags |= BBR_TLP;
4781 	}
4782 	if (rsm && (rsm->r_start == bbr->r_ctl.rc_last_tlp_seq) &&
4783 	    (bbr->r_ctl.rc_tlp_seg_send_cnt > bbr_tlp_max_resend)) {
4784 		/*
4785 		 * We have retransmitted to many times for TLP. Switch to
4786 		 * the regular RTO timer
4787 		 */
4788 		goto restore;
4789 	}
4790 	bbr_log_to_event(bbr, cts, BBR_TO_FRM_TLP);
4791 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_TLP;
4792 	return (0);
4793 }
4794 
4795 /*
4796  * Delayed ack Timer, here we simply need to setup the
4797  * ACK_NOW flag and remove the DELACK flag. From there
4798  * the output routine will send the ack out.
4799  *
4800  * We only return 1, saying don't proceed, if all timers
4801  * are stopped (destroyed PCB?).
4802  */
4803 static int
4804 bbr_timeout_delack(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4805 {
4806 	if (bbr->rc_all_timers_stopped) {
4807 		return (1);
4808 	}
4809 	bbr_log_to_event(bbr, cts, BBR_TO_FRM_DELACK);
4810 	tp->t_flags &= ~TF_DELACK;
4811 	tp->t_flags |= TF_ACKNOW;
4812 	KMOD_TCPSTAT_INC(tcps_delack);
4813 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_DELACK;
4814 	return (0);
4815 }
4816 
4817 /*
4818  * Persists timer, here we simply need to setup the
4819  * FORCE-DATA flag the output routine will send
4820  * the one byte send.
4821  *
4822  * We only return 1, saying don't proceed, if all timers
4823  * are stopped (destroyed PCB?).
4824  */
4825 static int
4826 bbr_timeout_persist(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4827 {
4828 	struct tcptemp *t_template;
4829 	int32_t retval = 1;
4830 
4831 	if (bbr->rc_all_timers_stopped) {
4832 		return (1);
4833 	}
4834 	if (bbr->rc_in_persist == 0)
4835 		return (0);
4836 	KASSERT(tp->t_inpcb != NULL,
4837 	    ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
4838 	/*
4839 	 * Persistence timer into zero window. Force a byte to be output, if
4840 	 * possible.
4841 	 */
4842 	bbr_log_to_event(bbr, cts, BBR_TO_FRM_PERSIST);
4843 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_PERSIT;
4844 	KMOD_TCPSTAT_INC(tcps_persisttimeo);
4845 	/*
4846 	 * Have we exceeded the user specified progress time?
4847 	 */
4848 	if (bbr_progress_timeout_check(bbr)) {
4849 		tcp_set_inp_to_drop(bbr->rc_inp, ETIMEDOUT);
4850 		goto out;
4851 	}
4852 	/*
4853 	 * Hack: if the peer is dead/unreachable, we do not time out if the
4854 	 * window is closed.  After a full backoff, drop the connection if
4855 	 * the idle time (no responses to probes) reaches the maximum
4856 	 * backoff that we would use if retransmitting.
4857 	 */
4858 	if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
4859 	    (ticks - tp->t_rcvtime >= tcp_maxpersistidle ||
4860 	    ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) {
4861 		KMOD_TCPSTAT_INC(tcps_persistdrop);
4862 		tcp_set_inp_to_drop(bbr->rc_inp, ETIMEDOUT);
4863 		goto out;
4864 	}
4865 	if ((sbavail(&bbr->rc_inp->inp_socket->so_snd) == 0) &&
4866 	    tp->snd_una == tp->snd_max) {
4867 		bbr_exit_persist(tp, bbr, cts, __LINE__);
4868 		retval = 0;
4869 		goto out;
4870 	}
4871 	/*
4872 	 * If the user has closed the socket then drop a persisting
4873 	 * connection after a much reduced timeout.
4874 	 */
4875 	if (tp->t_state > TCPS_CLOSE_WAIT &&
4876 	    (ticks - tp->t_rcvtime) >= TCPTV_PERSMAX) {
4877 		KMOD_TCPSTAT_INC(tcps_persistdrop);
4878 		tcp_set_inp_to_drop(bbr->rc_inp, ETIMEDOUT);
4879 		goto out;
4880 	}
4881 	t_template = tcpip_maketemplate(bbr->rc_inp);
4882 	if (t_template) {
4883 		tcp_respond(tp, t_template->tt_ipgen,
4884 			    &t_template->tt_t, (struct mbuf *)NULL,
4885 			    tp->rcv_nxt, tp->snd_una - 1, 0);
4886 		/* This sends an ack */
4887 		if (tp->t_flags & TF_DELACK)
4888 			tp->t_flags &= ~TF_DELACK;
4889 		free(t_template, M_TEMP);
4890 	}
4891 	if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
4892 		tp->t_rxtshift++;
4893 	bbr_start_hpts_timer(bbr, tp, cts, 3, 0, 0);
4894 out:
4895 	return (retval);
4896 }
4897 
4898 /*
4899  * If a keepalive goes off, we had no other timers
4900  * happening. We always return 1 here since this
4901  * routine either drops the connection or sends
4902  * out a segment with respond.
4903  */
4904 static int
4905 bbr_timeout_keepalive(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4906 {
4907 	struct tcptemp *t_template;
4908 	struct inpcb *inp;
4909 
4910 	if (bbr->rc_all_timers_stopped) {
4911 		return (1);
4912 	}
4913 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_KEEP;
4914 	inp = tp->t_inpcb;
4915 	bbr_log_to_event(bbr, cts, BBR_TO_FRM_KEEP);
4916 	/*
4917 	 * Keep-alive timer went off; send something or drop connection if
4918 	 * idle for too long.
4919 	 */
4920 	KMOD_TCPSTAT_INC(tcps_keeptimeo);
4921 	if (tp->t_state < TCPS_ESTABLISHED)
4922 		goto dropit;
4923 	if ((V_tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
4924 	    tp->t_state <= TCPS_CLOSING) {
4925 		if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp))
4926 			goto dropit;
4927 		/*
4928 		 * Send a packet designed to force a response if the peer is
4929 		 * up and reachable: either an ACK if the connection is
4930 		 * still alive, or an RST if the peer has closed the
4931 		 * connection due to timeout or reboot. Using sequence
4932 		 * number tp->snd_una-1 causes the transmitted zero-length
4933 		 * segment to lie outside the receive window; by the
4934 		 * protocol spec, this requires the correspondent TCP to
4935 		 * respond.
4936 		 */
4937 		KMOD_TCPSTAT_INC(tcps_keepprobe);
4938 		t_template = tcpip_maketemplate(inp);
4939 		if (t_template) {
4940 			tcp_respond(tp, t_template->tt_ipgen,
4941 			    &t_template->tt_t, (struct mbuf *)NULL,
4942 			    tp->rcv_nxt, tp->snd_una - 1, 0);
4943 			free(t_template, M_TEMP);
4944 		}
4945 	}
4946 	bbr_start_hpts_timer(bbr, tp, cts, 4, 0, 0);
4947 	return (1);
4948 dropit:
4949 	KMOD_TCPSTAT_INC(tcps_keepdrops);
4950 	tcp_set_inp_to_drop(bbr->rc_inp, ETIMEDOUT);
4951 	return (1);
4952 }
4953 
4954 /*
4955  * Retransmit helper function, clear up all the ack
4956  * flags and take care of important book keeping.
4957  */
4958 static void
4959 bbr_remxt_tmr(struct tcpcb *tp)
4960 {
4961 	/*
4962 	 * The retransmit timer went off, all sack'd blocks must be
4963 	 * un-acked.
4964 	 */
4965 	struct bbr_sendmap *rsm, *trsm = NULL;
4966 	struct tcp_bbr *bbr;
4967 	uint32_t cts, lost;
4968 
4969 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
4970 	cts = tcp_get_usecs(&bbr->rc_tv);
4971 	lost = bbr->r_ctl.rc_lost;
4972 	if (bbr->r_state && (bbr->r_state != tp->t_state))
4973 		bbr_set_state(tp, bbr, 0);
4974 
4975 	TAILQ_FOREACH(rsm, &bbr->r_ctl.rc_map, r_next) {
4976 		if (rsm->r_flags & BBR_ACKED) {
4977 			uint32_t old_flags;
4978 
4979 			rsm->r_dupack = 0;
4980 			if (rsm->r_in_tmap == 0) {
4981 				/* We must re-add it back to the tlist */
4982 				if (trsm == NULL) {
4983 					TAILQ_INSERT_HEAD(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
4984 				} else {
4985 					TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, trsm, rsm, r_tnext);
4986 				}
4987 				rsm->r_in_tmap = 1;
4988 			}
4989 			old_flags = rsm->r_flags;
4990 			rsm->r_flags |= BBR_RXT_CLEARED;
4991 			rsm->r_flags &= ~(BBR_ACKED | BBR_SACK_PASSED | BBR_WAS_SACKPASS);
4992 			bbr_log_type_rsmclear(bbr, cts, rsm, old_flags, __LINE__);
4993 		} else {
4994 			if ((rsm->r_flags & BBR_MARKED_LOST) == 0) {
4995 				bbr->r_ctl.rc_lost += rsm->r_end - rsm->r_start;
4996 				bbr->r_ctl.rc_lost_bytes += rsm->r_end - rsm->r_start;
4997 			}
4998 			if (bbr_marks_rxt_sack_passed) {
4999 				/*
5000 				 * With this option, we will rack out
5001 				 * in 1ms increments the rest of the packets.
5002 				 */
5003 				rsm->r_flags |= BBR_SACK_PASSED | BBR_MARKED_LOST;
5004 				rsm->r_flags &= ~BBR_WAS_SACKPASS;
5005 			} else {
5006 				/*
5007 				 * With this option we only mark them lost
5008 				 * and remove all sack'd markings. We will run
5009 				 * another RXT or a TLP. This will cause
5010 				 * us to eventually send more based on what
5011 				 * ack's come in.
5012 				 */
5013 				rsm->r_flags |= BBR_MARKED_LOST;
5014 				rsm->r_flags &= ~BBR_WAS_SACKPASS;
5015 				rsm->r_flags &= ~BBR_SACK_PASSED;
5016 			}
5017 		}
5018 		trsm = rsm;
5019 	}
5020 	bbr->r_ctl.rc_resend = TAILQ_FIRST(&bbr->r_ctl.rc_map);
5021 	/* Clear the count (we just un-acked them) */
5022 	bbr_log_to_event(bbr, cts, BBR_TO_FRM_TMR);
5023 	bbr->rc_tlp_new_data = 0;
5024 	bbr->r_ctl.rc_tlp_seg_send_cnt = 0;
5025 	/* zap the behindness on a rxt */
5026 	bbr->r_ctl.rc_hptsi_agg_delay = 0;
5027 	bbr->r_agg_early_set = 0;
5028 	bbr->r_ctl.rc_agg_early = 0;
5029 	bbr->rc_tlp_rtx_out = 0;
5030 	bbr->r_ctl.rc_sacked = 0;
5031 	bbr->r_ctl.rc_sacklast = NULL;
5032 	bbr->r_timer_override = 1;
5033 	bbr_lt_bw_sampling(bbr, cts, (bbr->r_ctl.rc_lost > lost));
5034 }
5035 
5036 /*
5037  * Re-transmit timeout! If we drop the PCB we will return 1, otherwise
5038  * we will setup to retransmit the lowest seq number outstanding.
5039  */
5040 static int
5041 bbr_timeout_rxt(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
5042 {
5043 	int32_t rexmt;
5044 	int32_t retval = 0;
5045 	bool isipv6;
5046 
5047 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_RXT;
5048 	if (bbr->rc_all_timers_stopped) {
5049 		return (1);
5050 	}
5051 	if (TCPS_HAVEESTABLISHED(tp->t_state) &&
5052 	    (tp->snd_una == tp->snd_max)) {
5053 		/* Nothing outstanding .. nothing to do */
5054 		return (0);
5055 	}
5056 	/*
5057 	 * Retransmission timer went off.  Message has not been acked within
5058 	 * retransmit interval.  Back off to a longer retransmit interval
5059 	 * and retransmit one segment.
5060 	 */
5061 	if (bbr_progress_timeout_check(bbr)) {
5062 		retval = 1;
5063 		tcp_set_inp_to_drop(bbr->rc_inp, ETIMEDOUT);
5064 		goto out;
5065 	}
5066 	bbr_remxt_tmr(tp);
5067 	if ((bbr->r_ctl.rc_resend == NULL) ||
5068 	    ((bbr->r_ctl.rc_resend->r_flags & BBR_RWND_COLLAPSED) == 0)) {
5069 		/*
5070 		 * If the rwnd collapsed on
5071 		 * the one we are retransmitting
5072 		 * it does not count against the
5073 		 * rxt count.
5074 		 */
5075 		tp->t_rxtshift++;
5076 	}
5077 	if (tp->t_rxtshift > TCP_MAXRXTSHIFT) {
5078 		tp->t_rxtshift = TCP_MAXRXTSHIFT;
5079 		KMOD_TCPSTAT_INC(tcps_timeoutdrop);
5080 		retval = 1;
5081 		tcp_set_inp_to_drop(bbr->rc_inp,
5082 		    (tp->t_softerror ? (uint16_t) tp->t_softerror : ETIMEDOUT));
5083 		goto out;
5084 	}
5085 	if (tp->t_state == TCPS_SYN_SENT) {
5086 		/*
5087 		 * If the SYN was retransmitted, indicate CWND to be limited
5088 		 * to 1 segment in cc_conn_init().
5089 		 */
5090 		tp->snd_cwnd = 1;
5091 	} else if (tp->t_rxtshift == 1) {
5092 		/*
5093 		 * first retransmit; record ssthresh and cwnd so they can be
5094 		 * recovered if this turns out to be a "bad" retransmit. A
5095 		 * retransmit is considered "bad" if an ACK for this segment
5096 		 * is received within RTT/2 interval; the assumption here is
5097 		 * that the ACK was already in flight.  See "On Estimating
5098 		 * End-to-End Network Path Properties" by Allman and Paxson
5099 		 * for more details.
5100 		 */
5101 		tp->snd_cwnd = tp->t_maxseg - bbr->rc_last_options;
5102 		if (!IN_RECOVERY(tp->t_flags)) {
5103 			tp->snd_cwnd_prev = tp->snd_cwnd;
5104 			tp->snd_ssthresh_prev = tp->snd_ssthresh;
5105 			tp->snd_recover_prev = tp->snd_recover;
5106 			tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1));
5107 			tp->t_flags |= TF_PREVVALID;
5108 		} else {
5109 			tp->t_flags &= ~TF_PREVVALID;
5110 		}
5111 		tp->snd_cwnd = tp->t_maxseg - bbr->rc_last_options;
5112 	} else {
5113 		tp->snd_cwnd = tp->t_maxseg - bbr->rc_last_options;
5114 		tp->t_flags &= ~TF_PREVVALID;
5115 	}
5116 	KMOD_TCPSTAT_INC(tcps_rexmttimeo);
5117 	if ((tp->t_state == TCPS_SYN_SENT) ||
5118 	    (tp->t_state == TCPS_SYN_RECEIVED))
5119 		rexmt = USEC_2_TICKS(BBR_INITIAL_RTO) * tcp_backoff[tp->t_rxtshift];
5120 	else
5121 		rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
5122 	TCPT_RANGESET(tp->t_rxtcur, rexmt,
5123 	    MSEC_2_TICKS(bbr->r_ctl.rc_min_rto_ms),
5124 	    MSEC_2_TICKS(((uint32_t)bbr->rc_max_rto_sec) * 1000));
5125 	/*
5126 	 * We enter the path for PLMTUD if connection is established or, if
5127 	 * connection is FIN_WAIT_1 status, reason for the last is that if
5128 	 * amount of data we send is very small, we could send it in couple
5129 	 * of packets and process straight to FIN. In that case we won't
5130 	 * catch ESTABLISHED state.
5131 	 */
5132 #ifdef INET6
5133 	isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) ? true : false;
5134 #else
5135 	isipv6 = false;
5136 #endif
5137 	if (((V_tcp_pmtud_blackhole_detect == 1) ||
5138 	    (V_tcp_pmtud_blackhole_detect == 2 && !isipv6) ||
5139 	    (V_tcp_pmtud_blackhole_detect == 3 && isipv6)) &&
5140 	    ((tp->t_state == TCPS_ESTABLISHED) ||
5141 	    (tp->t_state == TCPS_FIN_WAIT_1))) {
5142 
5143 		/*
5144 		 * Idea here is that at each stage of mtu probe (usually,
5145 		 * 1448 -> 1188 -> 524) should be given 2 chances to recover
5146 		 * before further clamping down. 'tp->t_rxtshift % 2 == 0'
5147 		 * should take care of that.
5148 		 */
5149 		if (((tp->t_flags2 & (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) ==
5150 		    (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) &&
5151 		    (tp->t_rxtshift >= 2 && tp->t_rxtshift < 6 &&
5152 		    tp->t_rxtshift % 2 == 0)) {
5153 			/*
5154 			 * Enter Path MTU Black-hole Detection mechanism: -
5155 			 * Disable Path MTU Discovery (IP "DF" bit). -
5156 			 * Reduce MTU to lower value than what we negotiated
5157 			 * with peer.
5158 			 */
5159 			if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) == 0) {
5160 				/*
5161 				 * Record that we may have found a black
5162 				 * hole.
5163 				 */
5164 				tp->t_flags2 |= TF2_PLPMTU_BLACKHOLE;
5165 				/* Keep track of previous MSS. */
5166 				tp->t_pmtud_saved_maxseg = tp->t_maxseg;
5167 			}
5168 			/*
5169 			 * Reduce the MSS to blackhole value or to the
5170 			 * default in an attempt to retransmit.
5171 			 */
5172 #ifdef INET6
5173 			isipv6 = bbr->r_is_v6;
5174 			if (isipv6 &&
5175 			    tp->t_maxseg > V_tcp_v6pmtud_blackhole_mss) {
5176 				/* Use the sysctl tuneable blackhole MSS. */
5177 				tp->t_maxseg = V_tcp_v6pmtud_blackhole_mss;
5178 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated);
5179 			} else if (isipv6) {
5180 				/* Use the default MSS. */
5181 				tp->t_maxseg = V_tcp_v6mssdflt;
5182 				/*
5183 				 * Disable Path MTU Discovery when we switch
5184 				 * to minmss.
5185 				 */
5186 				tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
5187 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
5188 			}
5189 #endif
5190 #if defined(INET6) && defined(INET)
5191 			else
5192 #endif
5193 #ifdef INET
5194 			if (tp->t_maxseg > V_tcp_pmtud_blackhole_mss) {
5195 				/* Use the sysctl tuneable blackhole MSS. */
5196 				tp->t_maxseg = V_tcp_pmtud_blackhole_mss;
5197 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated);
5198 			} else {
5199 				/* Use the default MSS. */
5200 				tp->t_maxseg = V_tcp_mssdflt;
5201 				/*
5202 				 * Disable Path MTU Discovery when we switch
5203 				 * to minmss.
5204 				 */
5205 				tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
5206 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
5207 			}
5208 #endif
5209 		} else {
5210 			/*
5211 			 * If further retransmissions are still unsuccessful
5212 			 * with a lowered MTU, maybe this isn't a blackhole
5213 			 * and we restore the previous MSS and blackhole
5214 			 * detection flags. The limit '6' is determined by
5215 			 * giving each probe stage (1448, 1188, 524) 2
5216 			 * chances to recover.
5217 			 */
5218 			if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) &&
5219 			    (tp->t_rxtshift >= 6)) {
5220 				tp->t_flags2 |= TF2_PLPMTU_PMTUD;
5221 				tp->t_flags2 &= ~TF2_PLPMTU_BLACKHOLE;
5222 				tp->t_maxseg = tp->t_pmtud_saved_maxseg;
5223 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_failed);
5224 			}
5225 		}
5226 	}
5227 	/*
5228 	 * Disable RFC1323 and SACK if we haven't got any response to our
5229 	 * third SYN to work-around some broken terminal servers (most of
5230 	 * which have hopefully been retired) that have bad VJ header
5231 	 * compression code which trashes TCP segments containing
5232 	 * unknown-to-them TCP options.
5233 	 */
5234 	if (tcp_rexmit_drop_options && (tp->t_state == TCPS_SYN_SENT) &&
5235 	    (tp->t_rxtshift == 3))
5236 		tp->t_flags &= ~(TF_REQ_SCALE | TF_REQ_TSTMP | TF_SACK_PERMIT);
5237 	/*
5238 	 * If we backed off this far, our srtt estimate is probably bogus.
5239 	 * Clobber it so we'll take the next rtt measurement as our srtt;
5240 	 * move the current srtt into rttvar to keep the current retransmit
5241 	 * times until then.
5242 	 */
5243 	if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
5244 #ifdef INET6
5245 		if (bbr->r_is_v6)
5246 			in6_losing(tp->t_inpcb);
5247 		else
5248 #endif
5249 			in_losing(tp->t_inpcb);
5250 		tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
5251 		tp->t_srtt = 0;
5252 	}
5253 	sack_filter_clear(&bbr->r_ctl.bbr_sf, tp->snd_una);
5254 	tp->snd_recover = tp->snd_max;
5255 	tp->t_flags |= TF_ACKNOW;
5256 	tp->t_rtttime = 0;
5257 out:
5258 	return (retval);
5259 }
5260 
5261 static int
5262 bbr_process_timers(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts, uint8_t hpts_calling)
5263 {
5264 	int32_t ret = 0;
5265 	int32_t timers = (bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK);
5266 
5267 	if (timers == 0) {
5268 		return (0);
5269 	}
5270 	if (tp->t_state == TCPS_LISTEN) {
5271 		/* no timers on listen sockets */
5272 		if (bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)
5273 			return (0);
5274 		return (1);
5275 	}
5276 	if (TSTMP_LT(cts, bbr->r_ctl.rc_timer_exp)) {
5277 		uint32_t left;
5278 
5279 		if (bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
5280 			ret = -1;
5281 			bbr_log_to_processing(bbr, cts, ret, 0, hpts_calling);
5282 			return (0);
5283 		}
5284 		if (hpts_calling == 0) {
5285 			ret = -2;
5286 			bbr_log_to_processing(bbr, cts, ret, 0, hpts_calling);
5287 			return (0);
5288 		}
5289 		/*
5290 		 * Ok our timer went off early and we are not paced false
5291 		 * alarm, go back to sleep.
5292 		 */
5293 		left = bbr->r_ctl.rc_timer_exp - cts;
5294 		ret = -3;
5295 		bbr_log_to_processing(bbr, cts, ret, left, hpts_calling);
5296 		tcp_hpts_insert(tp->t_inpcb, HPTS_USEC_TO_SLOTS(left));
5297 		return (1);
5298 	}
5299 	bbr->rc_tmr_stopped = 0;
5300 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_MASK;
5301 	if (timers & PACE_TMR_DELACK) {
5302 		ret = bbr_timeout_delack(tp, bbr, cts);
5303 	} else if (timers & PACE_TMR_PERSIT) {
5304 		ret = bbr_timeout_persist(tp, bbr, cts);
5305 	} else if (timers & PACE_TMR_RACK) {
5306 		bbr->r_ctl.rc_tlp_rxt_last_time = cts;
5307 		ret = bbr_timeout_rack(tp, bbr, cts);
5308 	} else if (timers & PACE_TMR_TLP) {
5309 		bbr->r_ctl.rc_tlp_rxt_last_time = cts;
5310 		ret = bbr_timeout_tlp(tp, bbr, cts);
5311 	} else if (timers & PACE_TMR_RXT) {
5312 		bbr->r_ctl.rc_tlp_rxt_last_time = cts;
5313 		ret = bbr_timeout_rxt(tp, bbr, cts);
5314 	} else if (timers & PACE_TMR_KEEP) {
5315 		ret = bbr_timeout_keepalive(tp, bbr, cts);
5316 	}
5317 	bbr_log_to_processing(bbr, cts, ret, timers, hpts_calling);
5318 	return (ret);
5319 }
5320 
5321 static void
5322 bbr_timer_cancel(struct tcp_bbr *bbr, int32_t line, uint32_t cts)
5323 {
5324 	if (bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK) {
5325 		uint8_t hpts_removed = 0;
5326 
5327 		if (bbr->rc_inp->inp_in_hpts &&
5328 		    (bbr->rc_timer_first == 1)) {
5329 			/*
5330 			 * If we are canceling timer's when we have the
5331 			 * timer ahead of the output being paced. We also
5332 			 * must remove ourselves from the hpts.
5333 			 */
5334 			hpts_removed = 1;
5335 			tcp_hpts_remove(bbr->rc_inp, HPTS_REMOVE_OUTPUT);
5336 			if (bbr->r_ctl.rc_last_delay_val) {
5337 				/* Update the last hptsi delay too */
5338 				uint32_t time_since_send;
5339 
5340 				if (TSTMP_GT(cts, bbr->rc_pacer_started))
5341 					time_since_send = cts - bbr->rc_pacer_started;
5342 				else
5343 					time_since_send = 0;
5344 				if (bbr->r_ctl.rc_last_delay_val > time_since_send) {
5345 					/* Cut down our slot time */
5346 					bbr->r_ctl.rc_last_delay_val -= time_since_send;
5347 				} else {
5348 					bbr->r_ctl.rc_last_delay_val = 0;
5349 				}
5350 				bbr->rc_pacer_started = cts;
5351 			}
5352 		}
5353 		bbr->rc_timer_first = 0;
5354 		bbr_log_to_cancel(bbr, line, cts, hpts_removed);
5355 		bbr->rc_tmr_stopped = bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK;
5356 		bbr->r_ctl.rc_hpts_flags &= ~(PACE_TMR_MASK);
5357 	}
5358 }
5359 
5360 static void
5361 bbr_timer_stop(struct tcpcb *tp, uint32_t timer_type)
5362 {
5363 	struct tcp_bbr *bbr;
5364 
5365 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
5366 	bbr->rc_all_timers_stopped = 1;
5367 	return;
5368 }
5369 
5370 /*
5371  * stop all timers always returning 0.
5372  */
5373 static int
5374 bbr_stopall(struct tcpcb *tp)
5375 {
5376 	return (0);
5377 }
5378 
5379 static void
5380 bbr_timer_activate(struct tcpcb *tp, uint32_t timer_type, uint32_t delta)
5381 {
5382 	return;
5383 }
5384 
5385 /*
5386  * return true if a bbr timer (rack or tlp) is active.
5387  */
5388 static int
5389 bbr_timer_active(struct tcpcb *tp, uint32_t timer_type)
5390 {
5391 	return (0);
5392 }
5393 
5394 static uint32_t
5395 bbr_get_earliest_send_outstanding(struct tcp_bbr *bbr, struct bbr_sendmap *u_rsm, uint32_t cts)
5396 {
5397 	struct bbr_sendmap *rsm;
5398 
5399 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_tmap);
5400 	if ((rsm == NULL) || (u_rsm == rsm))
5401 		return (cts);
5402 	return(rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)]);
5403 }
5404 
5405 static void
5406 bbr_update_rsm(struct tcpcb *tp, struct tcp_bbr *bbr,
5407      struct bbr_sendmap *rsm, uint32_t cts, uint32_t pacing_time)
5408 {
5409 	int32_t idx;
5410 
5411 	rsm->r_rtr_cnt++;
5412 	rsm->r_dupack = 0;
5413 	if (rsm->r_rtr_cnt > BBR_NUM_OF_RETRANS) {
5414 		rsm->r_rtr_cnt = BBR_NUM_OF_RETRANS;
5415 		rsm->r_flags |= BBR_OVERMAX;
5416 	}
5417 	if (rsm->r_flags & BBR_RWND_COLLAPSED) {
5418 		/* Take off the collapsed flag at rxt */
5419 		rsm->r_flags &= ~BBR_RWND_COLLAPSED;
5420 	}
5421 	if (rsm->r_flags & BBR_MARKED_LOST) {
5422 		/* We have retransmitted, its no longer lost */
5423 		rsm->r_flags &= ~BBR_MARKED_LOST;
5424 		bbr->r_ctl.rc_lost_bytes -= rsm->r_end - rsm->r_start;
5425 	}
5426 	if (rsm->r_flags & BBR_RXT_CLEARED) {
5427 		/*
5428 		 * We hit a RXT timer on it and
5429 		 * we cleared the "acked" flag.
5430 		 * We now have it going back into
5431 		 * flight, we can remove the cleared
5432 		 * flag and possibly do accounting on
5433 		 * this piece.
5434 		 */
5435 		rsm->r_flags &= ~BBR_RXT_CLEARED;
5436 	}
5437 	if ((rsm->r_rtr_cnt > 1) && ((rsm->r_flags & BBR_TLP) == 0)) {
5438 		bbr->r_ctl.rc_holes_rxt += (rsm->r_end - rsm->r_start);
5439 		rsm->r_rtr_bytes += (rsm->r_end - rsm->r_start);
5440 	}
5441 	idx = rsm->r_rtr_cnt - 1;
5442 	rsm->r_tim_lastsent[idx] = cts;
5443 	rsm->r_pacing_delay = pacing_time;
5444 	rsm->r_delivered = bbr->r_ctl.rc_delivered;
5445 	rsm->r_ts_valid = bbr->rc_ts_valid;
5446 	if (bbr->rc_ts_valid)
5447 		rsm->r_del_ack_ts = bbr->r_ctl.last_inbound_ts;
5448 	if (bbr->r_ctl.r_app_limited_until)
5449 		rsm->r_app_limited = 1;
5450 	else
5451 		rsm->r_app_limited = 0;
5452 	if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW)
5453 		rsm->r_bbr_state = bbr_state_val(bbr);
5454 	else
5455 		rsm->r_bbr_state = 8;
5456 	if (rsm->r_flags & BBR_ACKED) {
5457 		/* Problably MTU discovery messing with us */
5458 		uint32_t old_flags;
5459 
5460 		old_flags = rsm->r_flags;
5461 		rsm->r_flags &= ~BBR_ACKED;
5462 		bbr_log_type_rsmclear(bbr, cts, rsm, old_flags, __LINE__);
5463 		bbr->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
5464 		if (bbr->r_ctl.rc_sacked == 0)
5465 			bbr->r_ctl.rc_sacklast = NULL;
5466 	}
5467 	if (rsm->r_in_tmap) {
5468 		TAILQ_REMOVE(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
5469 	}
5470 	TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
5471 	rsm->r_in_tmap = 1;
5472 	if (rsm->r_flags & BBR_SACK_PASSED) {
5473 		/* We have retransmitted due to the SACK pass */
5474 		rsm->r_flags &= ~BBR_SACK_PASSED;
5475 		rsm->r_flags |= BBR_WAS_SACKPASS;
5476 	}
5477 	rsm->r_first_sent_time = bbr_get_earliest_send_outstanding(bbr, rsm, cts);
5478 	rsm->r_flight_at_send = ctf_flight_size(bbr->rc_tp,
5479 						(bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
5480 	bbr->r_ctl.rc_next = TAILQ_NEXT(rsm, r_next);
5481 	if (bbr->r_ctl.rc_bbr_hptsi_gain > BBR_UNIT) {
5482 		rsm->r_is_gain = 1;
5483 		rsm->r_is_drain = 0;
5484 	} else if (bbr->r_ctl.rc_bbr_hptsi_gain < BBR_UNIT) {
5485 		rsm->r_is_drain = 1;
5486 		rsm->r_is_gain = 0;
5487 	} else {
5488 		rsm->r_is_drain = 0;
5489 		rsm->r_is_gain = 0;
5490 	}
5491 	rsm->r_del_time = bbr->r_ctl.rc_del_time; /* TEMP GOOGLE CODE */
5492 }
5493 
5494 /*
5495  * Returns 0, or the sequence where we stopped
5496  * updating. We also update the lenp to be the amount
5497  * of data left.
5498  */
5499 
5500 static uint32_t
5501 bbr_update_entry(struct tcpcb *tp, struct tcp_bbr *bbr,
5502     struct bbr_sendmap *rsm, uint32_t cts, int32_t *lenp, uint32_t pacing_time)
5503 {
5504 	/*
5505 	 * We (re-)transmitted starting at rsm->r_start for some length
5506 	 * (possibly less than r_end.
5507 	 */
5508 	struct bbr_sendmap *nrsm;
5509 	uint32_t c_end;
5510 	int32_t len;
5511 
5512 	len = *lenp;
5513 	c_end = rsm->r_start + len;
5514 	if (SEQ_GEQ(c_end, rsm->r_end)) {
5515 		/*
5516 		 * We retransmitted the whole piece or more than the whole
5517 		 * slopping into the next rsm.
5518 		 */
5519 		bbr_update_rsm(tp, bbr, rsm, cts, pacing_time);
5520 		if (c_end == rsm->r_end) {
5521 			*lenp = 0;
5522 			return (0);
5523 		} else {
5524 			int32_t act_len;
5525 
5526 			/* Hangs over the end return whats left */
5527 			act_len = rsm->r_end - rsm->r_start;
5528 			*lenp = (len - act_len);
5529 			return (rsm->r_end);
5530 		}
5531 		/* We don't get out of this block. */
5532 	}
5533 	/*
5534 	 * Here we retransmitted less than the whole thing which means we
5535 	 * have to split this into what was transmitted and what was not.
5536 	 */
5537 	nrsm = bbr_alloc_full_limit(bbr);
5538 	if (nrsm == NULL) {
5539 		*lenp = 0;
5540 		return (0);
5541 	}
5542 	/*
5543 	 * So here we are going to take the original rsm and make it what we
5544 	 * retransmitted. nrsm will be the tail portion we did not
5545 	 * retransmit. For example say the chunk was 1, 11 (10 bytes). And
5546 	 * we retransmitted 5 bytes i.e. 1, 5. The original piece shrinks to
5547 	 * 1, 6 and the new piece will be 6, 11.
5548 	 */
5549 	bbr_clone_rsm(bbr, nrsm, rsm, c_end);
5550 	TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_map, rsm, nrsm, r_next);
5551 	nrsm->r_dupack = 0;
5552 	if (rsm->r_in_tmap) {
5553 		TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
5554 		nrsm->r_in_tmap = 1;
5555 	}
5556 	rsm->r_flags &= (~BBR_HAS_FIN);
5557 	bbr_update_rsm(tp, bbr, rsm, cts, pacing_time);
5558 	*lenp = 0;
5559 	return (0);
5560 }
5561 
5562 static uint64_t
5563 bbr_get_hardware_rate(struct tcp_bbr *bbr)
5564 {
5565 	uint64_t bw;
5566 
5567 	bw = bbr_get_bw(bbr);
5568 	bw *= (uint64_t)bbr_hptsi_gain[BBR_SUB_GAIN];
5569 	bw /= (uint64_t)BBR_UNIT;
5570 	return(bw);
5571 }
5572 
5573 static void
5574 bbr_setup_less_of_rate(struct tcp_bbr *bbr, uint32_t cts,
5575 		       uint64_t act_rate, uint64_t rate_wanted)
5576 {
5577 	/*
5578 	 * We could not get a full gains worth
5579 	 * of rate.
5580 	 */
5581 	if (get_filter_value(&bbr->r_ctl.rc_delrate) >= act_rate) {
5582 		/* we can't even get the real rate */
5583 		uint64_t red;
5584 
5585 		bbr->skip_gain = 1;
5586 		bbr->gain_is_limited = 0;
5587 		red = get_filter_value(&bbr->r_ctl.rc_delrate) - act_rate;
5588 		if (red)
5589 			filter_reduce_by(&bbr->r_ctl.rc_delrate, red, cts);
5590 	} else {
5591 		/* We can use a lower gain */
5592 		bbr->skip_gain = 0;
5593 		bbr->gain_is_limited = 1;
5594 	}
5595 }
5596 
5597 static void
5598 bbr_update_hardware_pacing_rate(struct tcp_bbr *bbr, uint32_t cts)
5599 {
5600 	const struct tcp_hwrate_limit_table *nrte;
5601 	int error, rate = -1;
5602 
5603 	if (bbr->r_ctl.crte == NULL)
5604 		return;
5605 	if ((bbr->rc_inp->inp_route.ro_nh == NULL) ||
5606 	    (bbr->rc_inp->inp_route.ro_nh->nh_ifp == NULL)) {
5607 		/* Lost our routes? */
5608 		/* Clear the way for a re-attempt */
5609 		bbr->bbr_attempt_hdwr_pace = 0;
5610 lost_rate:
5611 		bbr->gain_is_limited = 0;
5612 		bbr->skip_gain = 0;
5613 		bbr->bbr_hdrw_pacing = 0;
5614 		counter_u64_add(bbr_flows_whdwr_pacing, -1);
5615 		counter_u64_add(bbr_flows_nohdwr_pacing, 1);
5616 		tcp_bbr_tso_size_check(bbr, cts);
5617 		return;
5618 	}
5619 	rate = bbr_get_hardware_rate(bbr);
5620 	nrte = tcp_chg_pacing_rate(bbr->r_ctl.crte,
5621 				   bbr->rc_tp,
5622 				   bbr->rc_inp->inp_route.ro_nh->nh_ifp,
5623 				   rate,
5624 				   (RS_PACING_GEQ|RS_PACING_SUB_OK),
5625 				   &error);
5626 	if (nrte == NULL) {
5627 		goto lost_rate;
5628 	}
5629 	if (nrte != bbr->r_ctl.crte) {
5630 		bbr->r_ctl.crte = nrte;
5631 		if (error == 0)  {
5632 			BBR_STAT_INC(bbr_hdwr_rl_mod_ok);
5633 			if (bbr->r_ctl.crte->rate < rate) {
5634 				/* We have a problem */
5635 				bbr_setup_less_of_rate(bbr, cts,
5636 						       bbr->r_ctl.crte->rate, rate);
5637 			} else {
5638 				/* We are good */
5639 				bbr->gain_is_limited = 0;
5640 				bbr->skip_gain = 0;
5641 			}
5642 		} else {
5643 			/* A failure should release the tag */
5644 			BBR_STAT_INC(bbr_hdwr_rl_mod_fail);
5645 			bbr->gain_is_limited = 0;
5646 			bbr->skip_gain = 0;
5647 			bbr->bbr_hdrw_pacing = 0;
5648 		}
5649 		bbr_type_log_hdwr_pacing(bbr,
5650 					 bbr->r_ctl.crte->ptbl->rs_ifp,
5651 					 rate,
5652 					 ((bbr->r_ctl.crte == NULL) ? 0 : bbr->r_ctl.crte->rate),
5653 					 __LINE__,
5654 					 cts,
5655 					 error);
5656 	}
5657 }
5658 
5659 static void
5660 bbr_adjust_for_hw_pacing(struct tcp_bbr *bbr, uint32_t cts)
5661 {
5662 	/*
5663 	 * If we have hardware pacing support
5664 	 * we need to factor that in for our
5665 	 * TSO size.
5666 	 */
5667 	const struct tcp_hwrate_limit_table *rlp;
5668 	uint32_t cur_delay, seg_sz, maxseg, new_tso, delta, hdwr_delay;
5669 
5670 	if ((bbr->bbr_hdrw_pacing == 0) ||
5671 	    (IN_RECOVERY(bbr->rc_tp->t_flags)) ||
5672 	    (bbr->r_ctl.crte == NULL))
5673 		return;
5674 	if (bbr->hw_pacing_set == 0) {
5675 		/* Not yet by the hdwr pacing count delay */
5676 		return;
5677 	}
5678 	if (bbr_hdwr_pace_adjust == 0) {
5679 		/* No adjustment */
5680 		return;
5681 	}
5682 	rlp = bbr->r_ctl.crte;
5683 	if (bbr->rc_tp->t_maxseg > bbr->rc_last_options)
5684 		maxseg = bbr->rc_tp->t_maxseg - bbr->rc_last_options;
5685 	else
5686 		maxseg = BBR_MIN_SEG - bbr->rc_last_options;
5687 	/*
5688 	 * So lets first get the
5689 	 * time we will take between
5690 	 * TSO sized sends currently without
5691 	 * hardware help.
5692 	 */
5693 	cur_delay = bbr_get_pacing_delay(bbr, BBR_UNIT,
5694 		        bbr->r_ctl.rc_pace_max_segs, cts, 1);
5695 	hdwr_delay = bbr->r_ctl.rc_pace_max_segs / maxseg;
5696 	hdwr_delay *= rlp->time_between;
5697 	if (cur_delay > hdwr_delay)
5698 		delta = cur_delay - hdwr_delay;
5699 	else
5700 		delta = 0;
5701 	bbr_log_type_tsosize(bbr, cts, delta, cur_delay, hdwr_delay,
5702 			     (bbr->r_ctl.rc_pace_max_segs / maxseg),
5703 			     1);
5704 	if (delta &&
5705 	    (delta < (max(rlp->time_between,
5706 			  bbr->r_ctl.bbr_hptsi_segments_delay_tar)))) {
5707 		/*
5708 		 * Now lets divide by the pacing
5709 		 * time between each segment the
5710 		 * hardware sends rounding up and
5711 		 * derive a bytes from that. We multiply
5712 		 * that by bbr_hdwr_pace_adjust to get
5713 		 * more bang for our buck.
5714 		 *
5715 		 * The goal is to have the software pacer
5716 		 * waiting no more than an additional
5717 		 * pacing delay if we can (without the
5718 		 * compensation i.e. x bbr_hdwr_pace_adjust).
5719 		 */
5720 		seg_sz = max(((cur_delay + rlp->time_between)/rlp->time_between),
5721 			     (bbr->r_ctl.rc_pace_max_segs/maxseg));
5722 		seg_sz *= bbr_hdwr_pace_adjust;
5723 		if (bbr_hdwr_pace_floor &&
5724 		    (seg_sz < bbr->r_ctl.crte->ptbl->rs_min_seg)) {
5725 			/* Currently hardware paces
5726 			 * out rs_min_seg segments at a time.
5727 			 * We need to make sure we always send at least
5728 			 * a full burst of bbr_hdwr_pace_floor down.
5729 			 */
5730 			seg_sz = bbr->r_ctl.crte->ptbl->rs_min_seg;
5731 		}
5732 		seg_sz *= maxseg;
5733 	} else if (delta == 0) {
5734 		/*
5735 		 * The highest pacing rate is
5736 		 * above our b/w gained. This means
5737 		 * we probably are going quite fast at
5738 		 * the hardware highest rate. Lets just multiply
5739 		 * the calculated TSO size by the
5740 		 * multiplier factor (its probably
5741 		 * 4 segments in the default config for
5742 		 * mlx).
5743 		 */
5744 		seg_sz = bbr->r_ctl.rc_pace_max_segs * bbr_hdwr_pace_adjust;
5745 		if (bbr_hdwr_pace_floor &&
5746 		    (seg_sz < bbr->r_ctl.crte->ptbl->rs_min_seg)) {
5747 			/* Currently hardware paces
5748 			 * out rs_min_seg segments at a time.
5749 			 * We need to make sure we always send at least
5750 			 * a full burst of bbr_hdwr_pace_floor down.
5751 			 */
5752 			seg_sz = bbr->r_ctl.crte->ptbl->rs_min_seg;
5753 		}
5754 	} else {
5755 		/*
5756 		 * The pacing time difference is so
5757 		 * big that the hardware will
5758 		 * pace out more rapidly then we
5759 		 * really want and then we
5760 		 * will have a long delay. Lets just keep
5761 		 * the same TSO size so its as if
5762 		 * we were not using hdwr pacing (we
5763 		 * just gain a bit of spacing from the
5764 		 * hardware if seg_sz > 1).
5765 		 */
5766 		seg_sz = bbr->r_ctl.rc_pace_max_segs;
5767 	}
5768 	if (seg_sz > bbr->r_ctl.rc_pace_max_segs)
5769 		new_tso = seg_sz;
5770 	else
5771 		new_tso = bbr->r_ctl.rc_pace_max_segs;
5772 	if (new_tso >= (PACE_MAX_IP_BYTES-maxseg))
5773 		new_tso = PACE_MAX_IP_BYTES - maxseg;
5774 
5775 	if (new_tso != bbr->r_ctl.rc_pace_max_segs) {
5776 		bbr_log_type_tsosize(bbr, cts, new_tso, 0, bbr->r_ctl.rc_pace_max_segs, maxseg, 0);
5777 		bbr->r_ctl.rc_pace_max_segs = new_tso;
5778 	}
5779 }
5780 
5781 static void
5782 tcp_bbr_tso_size_check(struct tcp_bbr *bbr, uint32_t cts)
5783 {
5784 	uint64_t bw;
5785 	uint32_t old_tso = 0, new_tso;
5786 	uint32_t maxseg, bytes;
5787 	uint32_t tls_seg=0;
5788 	/*
5789 	 * Google/linux uses the following algorithm to determine
5790 	 * the TSO size based on the b/w of the link (from Neal Cardwell email 9/27/18):
5791 	 *
5792 	 *  bytes = bw_in_bytes_per_second / 1000
5793 	 *  bytes = min(bytes, 64k)
5794 	 *  tso_segs = bytes / MSS
5795 	 *  if (bw < 1.2Mbs)
5796 	 *      min_tso_segs = 1
5797 	 *  else
5798 	 *	min_tso_segs = 2
5799 	 * tso_segs = max(tso_segs, min_tso_segs)
5800 	 *
5801 	 * * Note apply a device specific limit (we apply this in the
5802 	 *   tcp_m_copym).
5803 	 * Note that before the initial measurement is made google bursts out
5804 	 * a full iwnd just like new-reno/cubic.
5805 	 *
5806 	 * We do not use this algorithm. Instead we
5807 	 * use a two phased approach:
5808 	 *
5809 	 *  if ( bw <= per-tcb-cross-over)
5810 	 *     goal_tso =  calculate how much with this bw we
5811 	 *                 can send in goal-time seconds.
5812 	 *     if (goal_tso > mss)
5813 	 *         seg = goal_tso / mss
5814 	 *         tso = seg * mss
5815 	 *     else
5816          *         tso = mss
5817 	 *     if (tso > per-tcb-max)
5818 	 *         tso = per-tcb-max
5819 	 *  else if ( bw > 512Mbps)
5820 	 *     tso = max-tso (64k/mss)
5821 	 *  else
5822 	 *     goal_tso = bw / per-tcb-divsor
5823 	 *     seg = (goal_tso + mss-1)/mss
5824 	 *     tso = seg * mss
5825 	 *
5826 	 * if (tso < per-tcb-floor)
5827 	 *    tso = per-tcb-floor
5828 	 * if (tso > per-tcb-utter_max)
5829 	 *    tso = per-tcb-utter_max
5830 	 *
5831 	 * Note the default per-tcb-divisor is 1000 (same as google).
5832 	 * the goal cross over is 30Mbps however. To recreate googles
5833 	 * algorithm you need to set:
5834 	 *
5835 	 * cross-over = 23,168,000 bps
5836 	 * goal-time = 18000
5837 	 * per-tcb-max = 2
5838 	 * per-tcb-divisor = 1000
5839 	 * per-tcb-floor = 1
5840 	 *
5841 	 * This will get you "google bbr" behavior with respect to tso size.
5842 	 *
5843 	 * Note we do set anything TSO size until we are past the initial
5844 	 * window. Before that we gnerally use either a single MSS
5845 	 * or we use the full IW size (so we burst a IW at a time)
5846 	 * Also note that Hardware-TLS is special and does alternate
5847 	 * things to minimize PCI Bus Bandwidth use.
5848 	 */
5849 
5850 	if (bbr->rc_tp->t_maxseg > bbr->rc_last_options) {
5851 		maxseg = bbr->rc_tp->t_maxseg - bbr->rc_last_options;
5852 	} else {
5853 		maxseg = BBR_MIN_SEG - bbr->rc_last_options;
5854 	}
5855 #ifdef KERN_TLS
5856 	if (bbr->rc_inp->inp_socket->so_snd.sb_flags & SB_TLS_IFNET) {
5857 		tls_seg =  ctf_get_opt_tls_size(bbr->rc_inp->inp_socket, bbr->rc_tp->snd_wnd);
5858 		bbr->r_ctl.rc_pace_min_segs = (tls_seg + bbr->rc_last_options);
5859 	}
5860 #endif
5861 	old_tso = bbr->r_ctl.rc_pace_max_segs;
5862 	if (bbr->rc_past_init_win == 0) {
5863 		/*
5864 		 * Not enough data has been acknowledged to make a
5865 		 * judgement unless we are hardware TLS. Set up
5866 		 * the initial TSO based on if we are sending a
5867 		 * full IW at once or not.
5868 		 */
5869 		if (bbr->rc_use_google)
5870 			bbr->r_ctl.rc_pace_max_segs = ((bbr->rc_tp->t_maxseg - bbr->rc_last_options) * 2);
5871 		else if (bbr->bbr_init_win_cheat)
5872 			bbr->r_ctl.rc_pace_max_segs = bbr_initial_cwnd(bbr, bbr->rc_tp);
5873 		else
5874 			bbr->r_ctl.rc_pace_max_segs = bbr->rc_tp->t_maxseg - bbr->rc_last_options;
5875 		if (bbr->r_ctl.rc_pace_min_segs != bbr->rc_tp->t_maxseg)
5876 			bbr->r_ctl.rc_pace_min_segs = bbr->rc_tp->t_maxseg;
5877 #ifdef KERN_TLS
5878 		if ((bbr->rc_inp->inp_socket->so_snd.sb_flags & SB_TLS_IFNET) && tls_seg) {
5879 			/*
5880 			 * For hardware TLS we set our min to the tls_seg size.
5881 			 */
5882 			bbr->r_ctl.rc_pace_max_segs = tls_seg;
5883 			bbr->r_ctl.rc_pace_min_segs = tls_seg + bbr->rc_last_options;
5884 		}
5885 #endif
5886 		if (bbr->r_ctl.rc_pace_max_segs == 0) {
5887 			bbr->r_ctl.rc_pace_max_segs = maxseg;
5888 		}
5889 		bbr_log_type_tsosize(bbr, cts, bbr->r_ctl.rc_pace_max_segs, tls_seg, old_tso, maxseg, 0);
5890 #ifdef KERN_TLS
5891 		if ((bbr->rc_inp->inp_socket->so_snd.sb_flags & SB_TLS_IFNET) == 0)
5892 #endif
5893 			bbr_adjust_for_hw_pacing(bbr, cts);
5894 		return;
5895 	}
5896 	/**
5897 	 * Now lets set the TSO goal based on our delivery rate in
5898 	 * bytes per second. Note we only do this if
5899 	 * we have acked at least the initial cwnd worth of data.
5900 	 */
5901 	bw = bbr_get_bw(bbr);
5902 	if (IN_RECOVERY(bbr->rc_tp->t_flags) &&
5903 	     (bbr->rc_use_google == 0)) {
5904 		/* We clamp to one MSS in recovery */
5905 		new_tso = maxseg;
5906 	} else if (bbr->rc_use_google) {
5907 		int min_tso_segs;
5908 
5909 		/* Google considers the gain too */
5910 		if (bbr->r_ctl.rc_bbr_hptsi_gain != BBR_UNIT) {
5911 			bw *= bbr->r_ctl.rc_bbr_hptsi_gain;
5912 			bw /= BBR_UNIT;
5913 		}
5914 		bytes = bw / 1024;
5915 		if (bytes > (64 * 1024))
5916 			bytes = 64 * 1024;
5917 		new_tso = bytes / maxseg;
5918 		if (bw < ONE_POINT_TWO_MEG)
5919 			min_tso_segs = 1;
5920 		else
5921 			min_tso_segs = 2;
5922 		if (new_tso < min_tso_segs)
5923 			new_tso = min_tso_segs;
5924 		new_tso *= maxseg;
5925 	} else if (bbr->rc_no_pacing) {
5926 		new_tso = (PACE_MAX_IP_BYTES / maxseg) * maxseg;
5927 	} else if (bw <= bbr->r_ctl.bbr_cross_over) {
5928 		/*
5929 		 * Calculate the worse case b/w TSO if we are inserting no
5930 		 * more than a delay_target number of TSO's.
5931 		 */
5932 		uint32_t tso_len, min_tso;
5933 
5934 		tso_len = bbr_get_pacing_length(bbr, BBR_UNIT, bbr->r_ctl.bbr_hptsi_segments_delay_tar, bw);
5935 		if (tso_len > maxseg) {
5936 			new_tso = tso_len / maxseg;
5937 			if (new_tso > bbr->r_ctl.bbr_hptsi_segments_max)
5938 				new_tso = bbr->r_ctl.bbr_hptsi_segments_max;
5939 			new_tso *= maxseg;
5940 		} else {
5941 			/*
5942 			 * less than a full sized frame yikes.. long rtt or
5943 			 * low bw?
5944 			 */
5945 			min_tso = bbr_minseg(bbr);
5946 			if ((tso_len > min_tso) && (bbr_all_get_min == 0))
5947 				new_tso = rounddown(tso_len, min_tso);
5948 			else
5949 				new_tso = min_tso;
5950 		}
5951 	} else if (bw > FIVETWELVE_MBPS) {
5952 		/*
5953 		 * This guy is so fast b/w wise that we can TSO as large as
5954 		 * possible of segments that the NIC will allow.
5955 		 */
5956 		new_tso = rounddown(PACE_MAX_IP_BYTES, maxseg);
5957 	} else {
5958 		/*
5959 		 * This formula is based on attempting to send a segment or
5960 		 * more every bbr_hptsi_per_second. The default is 1000
5961 		 * which means you are targeting what you can send every 1ms
5962 		 * based on the peers bw.
5963 		 *
5964 		 * If the number drops to say 500, then you are looking more
5965 		 * at 2ms and you will raise how much we send in a single
5966 		 * TSO thus saving CPU (less bbr_output_wtime() calls). The
5967 		 * trade off of course is you will send more at once and
5968 		 * thus tend to clump up the sends into larger "bursts"
5969 		 * building a queue.
5970 		 */
5971 		bw /= bbr->r_ctl.bbr_hptsi_per_second;
5972 		new_tso = roundup(bw, (uint64_t)maxseg);
5973 		/*
5974 		 * Gate the floor to match what our lower than 48Mbps
5975 		 * algorithm does. The ceiling (bbr_hptsi_segments_max) thus
5976 		 * becomes the floor for this calculation.
5977 		 */
5978 		if (new_tso < (bbr->r_ctl.bbr_hptsi_segments_max * maxseg))
5979 			new_tso = (bbr->r_ctl.bbr_hptsi_segments_max * maxseg);
5980 	}
5981 	if (bbr->r_ctl.bbr_hptsi_segments_floor && (new_tso < (maxseg * bbr->r_ctl.bbr_hptsi_segments_floor)))
5982 		new_tso = maxseg * bbr->r_ctl.bbr_hptsi_segments_floor;
5983 	if (new_tso > PACE_MAX_IP_BYTES)
5984 		new_tso = rounddown(PACE_MAX_IP_BYTES, maxseg);
5985 	/* Enforce an utter maximum if we are not HW-TLS */
5986 #ifdef KERN_TLS
5987 	if ((bbr->rc_inp->inp_socket->so_snd.sb_flags & SB_TLS_IFNET) == 0)
5988 #endif
5989 		if (bbr->r_ctl.bbr_utter_max && (new_tso > (bbr->r_ctl.bbr_utter_max * maxseg))) {
5990 			new_tso = bbr->r_ctl.bbr_utter_max * maxseg;
5991 		}
5992 #ifdef KERN_TLS
5993 	if (tls_seg) {
5994 		/*
5995 		 * Lets move the output size
5996 		 * up to 1 or more TLS record sizes.
5997 		 */
5998 		uint32_t temp;
5999 
6000 		temp = roundup(new_tso, tls_seg);
6001 		new_tso = temp;
6002 		/* Back down if needed to under a full frame */
6003 		while (new_tso > PACE_MAX_IP_BYTES)
6004 			new_tso -= tls_seg;
6005 	}
6006 #endif
6007 	if (old_tso != new_tso) {
6008 		/* Only log changes */
6009 		bbr_log_type_tsosize(bbr, cts, new_tso, tls_seg, old_tso, maxseg, 0);
6010 		bbr->r_ctl.rc_pace_max_segs = new_tso;
6011 	}
6012 #ifdef KERN_TLS
6013 	if ((bbr->rc_inp->inp_socket->so_snd.sb_flags & SB_TLS_IFNET) &&
6014 	     tls_seg) {
6015 		bbr->r_ctl.rc_pace_min_segs = tls_seg + bbr->rc_last_options;
6016 	} else
6017 #endif
6018 		/* We have hardware pacing and not hardware TLS! */
6019 		bbr_adjust_for_hw_pacing(bbr, cts);
6020 }
6021 
6022 static void
6023 bbr_log_output(struct tcp_bbr *bbr, struct tcpcb *tp, struct tcpopt *to, int32_t len,
6024     uint32_t seq_out, uint8_t th_flags, int32_t err, uint32_t cts,
6025     struct mbuf *mb, int32_t * abandon, struct bbr_sendmap *hintrsm, uint32_t delay_calc,
6026     struct sockbuf *sb)
6027 {
6028 
6029 	struct bbr_sendmap *rsm, *nrsm;
6030 	register uint32_t snd_max, snd_una;
6031 	uint32_t pacing_time;
6032 	/*
6033 	 * Add to the RACK log of packets in flight or retransmitted. If
6034 	 * there is a TS option we will use the TS echoed, if not we will
6035 	 * grab a TS.
6036 	 *
6037 	 * Retransmissions will increment the count and move the ts to its
6038 	 * proper place. Note that if options do not include TS's then we
6039 	 * won't be able to effectively use the ACK for an RTT on a retran.
6040 	 *
6041 	 * Notes about r_start and r_end. Lets consider a send starting at
6042 	 * sequence 1 for 10 bytes. In such an example the r_start would be
6043 	 * 1 (starting sequence) but the r_end would be r_start+len i.e. 11.
6044 	 * This means that r_end is actually the first sequence for the next
6045 	 * slot (11).
6046 	 *
6047 	 */
6048 	INP_WLOCK_ASSERT(tp->t_inpcb);
6049 	if (err) {
6050 		/*
6051 		 * We don't log errors -- we could but snd_max does not
6052 		 * advance in this case either.
6053 		 */
6054 		return;
6055 	}
6056 	if (th_flags & TH_RST) {
6057 		/*
6058 		 * We don't log resets and we return immediately from
6059 		 * sending
6060 		 */
6061 		*abandon = 1;
6062 		return;
6063 	}
6064 	snd_una = tp->snd_una;
6065 	if (th_flags & (TH_SYN | TH_FIN) && (hintrsm == NULL)) {
6066 		/*
6067 		 * The call to bbr_log_output is made before bumping
6068 		 * snd_max. This means we can record one extra byte on a SYN
6069 		 * or FIN if seq_out is adding more on and a FIN is present
6070 		 * (and we are not resending).
6071 		 */
6072 		if (th_flags & TH_SYN)
6073 			len++;
6074 		if (th_flags & TH_FIN)
6075 			len++;
6076 	}
6077 	if (SEQ_LEQ((seq_out + len), snd_una)) {
6078 		/* Are sending an old segment to induce an ack (keep-alive)? */
6079 		return;
6080 	}
6081 	if (SEQ_LT(seq_out, snd_una)) {
6082 		/* huh? should we panic? */
6083 		uint32_t end;
6084 
6085 		end = seq_out + len;
6086 		seq_out = snd_una;
6087 		len = end - seq_out;
6088 	}
6089 	snd_max = tp->snd_max;
6090 	if (len == 0) {
6091 		/* We don't log zero window probes */
6092 		return;
6093 	}
6094 	pacing_time = bbr_get_pacing_delay(bbr, bbr->r_ctl.rc_bbr_hptsi_gain, len, cts, 1);
6095 	/* First question is it a retransmission? */
6096 	if (seq_out == snd_max) {
6097 again:
6098 		rsm = bbr_alloc(bbr);
6099 		if (rsm == NULL) {
6100 			return;
6101 		}
6102 		rsm->r_flags = 0;
6103 		if (th_flags & TH_SYN)
6104 			rsm->r_flags |= BBR_HAS_SYN;
6105 		if (th_flags & TH_FIN)
6106 			rsm->r_flags |= BBR_HAS_FIN;
6107 		rsm->r_tim_lastsent[0] = cts;
6108 		rsm->r_rtr_cnt = 1;
6109 		rsm->r_rtr_bytes = 0;
6110 		rsm->r_start = seq_out;
6111 		rsm->r_end = rsm->r_start + len;
6112 		rsm->r_dupack = 0;
6113 		rsm->r_delivered = bbr->r_ctl.rc_delivered;
6114 		rsm->r_pacing_delay = pacing_time;
6115 		rsm->r_ts_valid = bbr->rc_ts_valid;
6116 		if (bbr->rc_ts_valid)
6117 			rsm->r_del_ack_ts = bbr->r_ctl.last_inbound_ts;
6118 		rsm->r_del_time = bbr->r_ctl.rc_del_time;
6119 		if (bbr->r_ctl.r_app_limited_until)
6120 			rsm->r_app_limited = 1;
6121 		else
6122 			rsm->r_app_limited = 0;
6123 		rsm->r_first_sent_time = bbr_get_earliest_send_outstanding(bbr, rsm, cts);
6124 		rsm->r_flight_at_send = ctf_flight_size(bbr->rc_tp,
6125 						(bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
6126 		/*
6127 		 * Here we must also add in this rsm since snd_max
6128 		 * is updated after we return from a new send.
6129 		 */
6130 		rsm->r_flight_at_send += len;
6131 		TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_map, rsm, r_next);
6132 		TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
6133 		rsm->r_in_tmap = 1;
6134 		if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW)
6135 			rsm->r_bbr_state = bbr_state_val(bbr);
6136 		else
6137 			rsm->r_bbr_state = 8;
6138 		if (bbr->r_ctl.rc_bbr_hptsi_gain > BBR_UNIT) {
6139 			rsm->r_is_gain = 1;
6140 			rsm->r_is_drain = 0;
6141 		} else if (bbr->r_ctl.rc_bbr_hptsi_gain < BBR_UNIT) {
6142 			rsm->r_is_drain = 1;
6143 			rsm->r_is_gain = 0;
6144 		} else {
6145 			rsm->r_is_drain = 0;
6146 			rsm->r_is_gain = 0;
6147 		}
6148 		return;
6149 	}
6150 	/*
6151 	 * If we reach here its a retransmission and we need to find it.
6152 	 */
6153 more:
6154 	if (hintrsm && (hintrsm->r_start == seq_out)) {
6155 		rsm = hintrsm;
6156 		hintrsm = NULL;
6157 	} else if (bbr->r_ctl.rc_next) {
6158 		/* We have a hint from a previous run */
6159 		rsm = bbr->r_ctl.rc_next;
6160 	} else {
6161 		/* No hints sorry */
6162 		rsm = NULL;
6163 	}
6164 	if ((rsm) && (rsm->r_start == seq_out)) {
6165 		/*
6166 		 * We used rc_next or hintrsm  to retransmit, hopefully the
6167 		 * likely case.
6168 		 */
6169 		seq_out = bbr_update_entry(tp, bbr, rsm, cts, &len, pacing_time);
6170 		if (len == 0) {
6171 			return;
6172 		} else {
6173 			goto more;
6174 		}
6175 	}
6176 	/* Ok it was not the last pointer go through it the hard way. */
6177 	TAILQ_FOREACH(rsm, &bbr->r_ctl.rc_map, r_next) {
6178 		if (rsm->r_start == seq_out) {
6179 			seq_out = bbr_update_entry(tp, bbr, rsm, cts, &len, pacing_time);
6180 			bbr->r_ctl.rc_next = TAILQ_NEXT(rsm, r_next);
6181 			if (len == 0) {
6182 				return;
6183 			} else {
6184 				continue;
6185 			}
6186 		}
6187 		if (SEQ_GEQ(seq_out, rsm->r_start) && SEQ_LT(seq_out, rsm->r_end)) {
6188 			/* Transmitted within this piece */
6189 			/*
6190 			 * Ok we must split off the front and then let the
6191 			 * update do the rest
6192 			 */
6193 			nrsm = bbr_alloc_full_limit(bbr);
6194 			if (nrsm == NULL) {
6195 				bbr_update_rsm(tp, bbr, rsm, cts, pacing_time);
6196 				return;
6197 			}
6198 			/*
6199 			 * copy rsm to nrsm and then trim the front of rsm
6200 			 * to not include this part.
6201 			 */
6202 			bbr_clone_rsm(bbr, nrsm, rsm, seq_out);
6203 			TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_map, rsm, nrsm, r_next);
6204 			if (rsm->r_in_tmap) {
6205 				TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
6206 				nrsm->r_in_tmap = 1;
6207 			}
6208 			rsm->r_flags &= (~BBR_HAS_FIN);
6209 			seq_out = bbr_update_entry(tp, bbr, nrsm, cts, &len, pacing_time);
6210 			if (len == 0) {
6211 				return;
6212 			}
6213 		}
6214 	}
6215 	/*
6216 	 * Hmm not found in map did they retransmit both old and on into the
6217 	 * new?
6218 	 */
6219 	if (seq_out == tp->snd_max) {
6220 		goto again;
6221 	} else if (SEQ_LT(seq_out, tp->snd_max)) {
6222 #ifdef BBR_INVARIANTS
6223 		printf("seq_out:%u len:%d snd_una:%u snd_max:%u -- but rsm not found?\n",
6224 		    seq_out, len, tp->snd_una, tp->snd_max);
6225 		printf("Starting Dump of all rack entries\n");
6226 		TAILQ_FOREACH(rsm, &bbr->r_ctl.rc_map, r_next) {
6227 			printf("rsm:%p start:%u end:%u\n",
6228 			    rsm, rsm->r_start, rsm->r_end);
6229 		}
6230 		printf("Dump complete\n");
6231 		panic("seq_out not found rack:%p tp:%p",
6232 		    bbr, tp);
6233 #endif
6234 	} else {
6235 #ifdef BBR_INVARIANTS
6236 		/*
6237 		 * Hmm beyond sndmax? (only if we are using the new rtt-pack
6238 		 * flag)
6239 		 */
6240 		panic("seq_out:%u(%d) is beyond snd_max:%u tp:%p",
6241 		    seq_out, len, tp->snd_max, tp);
6242 #endif
6243 	}
6244 }
6245 
6246 static void
6247 bbr_collapse_rtt(struct tcpcb *tp, struct tcp_bbr *bbr, int32_t rtt)
6248 {
6249 	/*
6250 	 * Collapse timeout back the cum-ack moved.
6251 	 */
6252 	tp->t_rxtshift = 0;
6253 	tp->t_softerror = 0;
6254 }
6255 
6256 
6257 static void
6258 tcp_bbr_xmit_timer(struct tcp_bbr *bbr, uint32_t rtt_usecs, uint32_t rsm_send_time, uint32_t r_start, uint32_t tsin)
6259 {
6260 	bbr->rtt_valid = 1;
6261 	bbr->r_ctl.cur_rtt = rtt_usecs;
6262 	bbr->r_ctl.ts_in = tsin;
6263 	if (rsm_send_time)
6264 		bbr->r_ctl.cur_rtt_send_time = rsm_send_time;
6265 }
6266 
6267 static void
6268 bbr_make_timestamp_determination(struct tcp_bbr *bbr)
6269 {
6270 	/**
6271 	 * We have in our bbr control:
6272 	 * 1) The timestamp we started observing cum-acks (bbr->r_ctl.bbr_ts_check_tstmp).
6273 	 * 2) Our timestamp indicating when we sent that packet (bbr->r_ctl.rsm->bbr_ts_check_our_cts).
6274 	 * 3) The current timestamp that just came in (bbr->r_ctl.last_inbound_ts)
6275 	 * 4) The time that the packet that generated that ack was sent (bbr->r_ctl.cur_rtt_send_time)
6276 	 *
6277 	 * Now we can calculate the time between the sends by doing:
6278 	 *
6279 	 * delta = bbr->r_ctl.cur_rtt_send_time - bbr->r_ctl.bbr_ts_check_our_cts
6280 	 *
6281 	 * And the peer's time between receiving them by doing:
6282 	 *
6283 	 * peer_delta = bbr->r_ctl.last_inbound_ts - bbr->r_ctl.bbr_ts_check_tstmp
6284 	 *
6285 	 * We want to figure out if the timestamp values are in msec, 10msec or usec.
6286 	 * We also may find that we can't use the timestamps if say we see
6287 	 * that the peer_delta indicates that though we may have taken 10ms to
6288 	 * pace out the data, it only saw 1ms between the two packets. This would
6289 	 * indicate that somewhere on the path is a batching entity that is giving
6290 	 * out time-slices of the actual b/w. This would mean we could not use
6291 	 * reliably the peers timestamps.
6292 	 *
6293 	 * We expect delta > peer_delta initially. Until we figure out the
6294 	 * timestamp difference which we will store in bbr->r_ctl.bbr_peer_tsratio.
6295 	 * If we place 1000 there then its a ms vs our usec. If we place 10000 there
6296 	 * then its 10ms vs our usec. If the peer is running a usec clock we would
6297 	 * put a 1 there. If the value is faster then ours, we will disable the
6298 	 * use of timestamps (though we could revist this later if we find it to be not
6299 	 * just an isolated one or two flows)).
6300 	 *
6301 	 * To detect the batching middle boxes we will come up with our compensation and
6302 	 * if with it in place, we find the peer is drastically off (by some margin) in
6303 	 * the smaller direction, then we will assume the worst case and disable use of timestamps.
6304 	 *
6305 	 */
6306 	uint64_t delta, peer_delta, delta_up;
6307 
6308 	delta = bbr->r_ctl.cur_rtt_send_time - bbr->r_ctl.bbr_ts_check_our_cts;
6309 	if (delta < bbr_min_usec_delta) {
6310 		/*
6311 		 * Have not seen a min amount of time
6312 		 * between our send times so we can
6313 		 * make a determination of the timestamp
6314 		 * yet.
6315 		 */
6316 		return;
6317 	}
6318 	peer_delta = bbr->r_ctl.last_inbound_ts - bbr->r_ctl.bbr_ts_check_tstmp;
6319 	if (peer_delta < bbr_min_peer_delta) {
6320 		/*
6321 		 * We may have enough in the form of
6322 		 * our delta but the peers number
6323 		 * has not changed that much. It could
6324 		 * be its clock ratio is such that
6325 		 * we need more data (10ms tick) or
6326 		 * there may be other compression scenarios
6327 		 * going on. In any event we need the
6328 		 * spread to be larger.
6329 		 */
6330 		return;
6331 	}
6332 	/* Ok lets first see which way our delta is going */
6333 	if (peer_delta > delta) {
6334 		/* Very unlikely, the peer without
6335 		 * compensation shows that it saw
6336 		 * the two sends arrive further apart
6337 		 * then we saw then in micro-seconds.
6338 		 */
6339 		if (peer_delta < (delta + ((delta * (uint64_t)1000)/ (uint64_t)bbr_delta_percent))) {
6340 			/* well it looks like the peer is a micro-second clock. */
6341 			bbr->rc_ts_clock_set = 1;
6342 			bbr->r_ctl.bbr_peer_tsratio = 1;
6343 		} else {
6344 			bbr->rc_ts_cant_be_used = 1;
6345 			bbr->rc_ts_clock_set = 1;
6346 		}
6347 		return;
6348 	}
6349 	/* Ok we know that the peer_delta is smaller than our send distance */
6350 	bbr->rc_ts_clock_set = 1;
6351 	/* First question is it within the percentage that they are using usec time? */
6352 	delta_up = (peer_delta * 1000) / (uint64_t)bbr_delta_percent;
6353 	if ((peer_delta + delta_up) >= delta) {
6354 		/* Its a usec clock */
6355 		bbr->r_ctl.bbr_peer_tsratio = 1;
6356 		bbr_log_tstmp_validation(bbr, peer_delta, delta);
6357 		return;
6358 	}
6359 	/* Ok if not usec, what about 10usec (though unlikely)? */
6360 	delta_up = (peer_delta * 1000 * 10) / (uint64_t)bbr_delta_percent;
6361 	if (((peer_delta * 10) + delta_up) >= delta) {
6362 		bbr->r_ctl.bbr_peer_tsratio = 10;
6363 		bbr_log_tstmp_validation(bbr, peer_delta, delta);
6364 		return;
6365 	}
6366 	/* And what about 100usec (though again unlikely)? */
6367 	delta_up = (peer_delta * 1000 * 100) / (uint64_t)bbr_delta_percent;
6368 	if (((peer_delta * 100) + delta_up) >= delta) {
6369 		bbr->r_ctl.bbr_peer_tsratio = 100;
6370 		bbr_log_tstmp_validation(bbr, peer_delta, delta);
6371 		return;
6372 	}
6373 	/* And how about 1 msec (the most likely one)? */
6374 	delta_up = (peer_delta * 1000 * 1000) / (uint64_t)bbr_delta_percent;
6375 	if (((peer_delta * 1000) + delta_up) >= delta) {
6376 		bbr->r_ctl.bbr_peer_tsratio = 1000;
6377 		bbr_log_tstmp_validation(bbr, peer_delta, delta);
6378 		return;
6379 	}
6380 	/* Ok if not msec could it be 10 msec? */
6381 	delta_up = (peer_delta * 1000 * 10000) / (uint64_t)bbr_delta_percent;
6382 	if (((peer_delta * 10000) + delta_up) >= delta) {
6383 		bbr->r_ctl.bbr_peer_tsratio = 10000;
6384 		return;
6385 	}
6386 	/* If we fall down here the clock tick so slowly we can't use it */
6387 	bbr->rc_ts_cant_be_used = 1;
6388 	bbr->r_ctl.bbr_peer_tsratio = 0;
6389 	bbr_log_tstmp_validation(bbr, peer_delta, delta);
6390 }
6391 
6392 /*
6393  * Collect new round-trip time estimate
6394  * and update averages and current timeout.
6395  */
6396 static void
6397 tcp_bbr_xmit_timer_commit(struct tcp_bbr *bbr, struct tcpcb *tp, uint32_t cts)
6398 {
6399 	int32_t delta;
6400 	uint32_t rtt, tsin;
6401 	int32_t rtt_ticks;
6402 
6403 
6404 	if (bbr->rtt_valid == 0)
6405 		/* No valid sample */
6406 		return;
6407 
6408 	rtt = bbr->r_ctl.cur_rtt;
6409 	tsin = bbr->r_ctl.ts_in;
6410 	if (bbr->rc_prtt_set_ts) {
6411 		/*
6412 		 * We are to force feed the rttProp filter due
6413 		 * to an entry into PROBE_RTT. This assures
6414 		 * that the times are sync'd between when we
6415 		 * go into PROBE_RTT and the filter expiration.
6416 		 *
6417 		 * Google does not use a true filter, so they do
6418 		 * this implicitly since they only keep one value
6419 		 * and when they enter probe-rtt they update the
6420 		 * value to the newest rtt.
6421 		 */
6422 		uint32_t rtt_prop;
6423 
6424 		bbr->rc_prtt_set_ts = 0;
6425 		rtt_prop = get_filter_value_small(&bbr->r_ctl.rc_rttprop);
6426 		if (rtt > rtt_prop)
6427 			filter_increase_by_small(&bbr->r_ctl.rc_rttprop, (rtt - rtt_prop), cts);
6428 		else
6429 			apply_filter_min_small(&bbr->r_ctl.rc_rttprop, rtt, cts);
6430 	}
6431 	if (bbr->rc_ack_was_delayed)
6432 		rtt += bbr->r_ctl.rc_ack_hdwr_delay;
6433 
6434 	if (rtt < bbr->r_ctl.rc_lowest_rtt)
6435 		bbr->r_ctl.rc_lowest_rtt = rtt;
6436 	bbr_log_rtt_sample(bbr, rtt, tsin);
6437 	if (bbr->r_init_rtt) {
6438 		/*
6439 		 * The initial rtt is not-trusted, nuke it and lets get
6440 		 * our first valid measurement in.
6441 		 */
6442 		bbr->r_init_rtt = 0;
6443 		tp->t_srtt = 0;
6444 	}
6445 	if ((bbr->rc_ts_clock_set == 0) && bbr->rc_ts_valid) {
6446 		/*
6447 		 * So we have not yet figured out
6448 		 * what the peers TSTMP value is
6449 		 * in (most likely ms). We need a
6450 		 * series of cum-ack's to determine
6451 		 * this reliably.
6452 		 */
6453 		if (bbr->rc_ack_is_cumack) {
6454 			if (bbr->rc_ts_data_set) {
6455 				/* Lets attempt to determine the timestamp granularity. */
6456 				bbr_make_timestamp_determination(bbr);
6457 			} else {
6458 				bbr->rc_ts_data_set = 1;
6459 				bbr->r_ctl.bbr_ts_check_tstmp = bbr->r_ctl.last_inbound_ts;
6460 				bbr->r_ctl.bbr_ts_check_our_cts = bbr->r_ctl.cur_rtt_send_time;
6461 			}
6462 		} else {
6463 			/*
6464 			 * We have to have consecutive acks
6465 			 * reset any "filled" state to none.
6466 			 */
6467 			bbr->rc_ts_data_set = 0;
6468 		}
6469 	}
6470 	/* Round it up */
6471 	rtt_ticks = USEC_2_TICKS((rtt + (USECS_IN_MSEC - 1)));
6472 	if (rtt_ticks == 0)
6473 		rtt_ticks = 1;
6474 	if (tp->t_srtt != 0) {
6475 		/*
6476 		 * srtt is stored as fixed point with 5 bits after the
6477 		 * binary point (i.e., scaled by 8).  The following magic is
6478 		 * equivalent to the smoothing algorithm in rfc793 with an
6479 		 * alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed point).
6480 		 * Adjust rtt to origin 0.
6481 		 */
6482 
6483 		delta = ((rtt_ticks - 1) << TCP_DELTA_SHIFT)
6484 		    - (tp->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT));
6485 
6486 		tp->t_srtt += delta;
6487 		if (tp->t_srtt <= 0)
6488 			tp->t_srtt = 1;
6489 
6490 		/*
6491 		 * We accumulate a smoothed rtt variance (actually, a
6492 		 * smoothed mean difference), then set the retransmit timer
6493 		 * to smoothed rtt + 4 times the smoothed variance. rttvar
6494 		 * is stored as fixed point with 4 bits after the binary
6495 		 * point (scaled by 16).  The following is equivalent to
6496 		 * rfc793 smoothing with an alpha of .75 (rttvar =
6497 		 * rttvar*3/4 + |delta| / 4).  This replaces rfc793's
6498 		 * wired-in beta.
6499 		 */
6500 		if (delta < 0)
6501 			delta = -delta;
6502 		delta -= tp->t_rttvar >> (TCP_RTTVAR_SHIFT - TCP_DELTA_SHIFT);
6503 		tp->t_rttvar += delta;
6504 		if (tp->t_rttvar <= 0)
6505 			tp->t_rttvar = 1;
6506 		if (tp->t_rttbest > tp->t_srtt + tp->t_rttvar)
6507 			tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
6508 	} else {
6509 		/*
6510 		 * No rtt measurement yet - use the unsmoothed rtt. Set the
6511 		 * variance to half the rtt (so our first retransmit happens
6512 		 * at 3*rtt).
6513 		 */
6514 		tp->t_srtt = rtt_ticks << TCP_RTT_SHIFT;
6515 		tp->t_rttvar = rtt_ticks << (TCP_RTTVAR_SHIFT - 1);
6516 		tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
6517 	}
6518 	KMOD_TCPSTAT_INC(tcps_rttupdated);
6519 	tp->t_rttupdated++;
6520 #ifdef STATS
6521 	stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, rtt_ticks));
6522 #endif
6523 	/*
6524 	 * the retransmit should happen at rtt + 4 * rttvar. Because of the
6525 	 * way we do the smoothing, srtt and rttvar will each average +1/2
6526 	 * tick of bias.  When we compute the retransmit timer, we want 1/2
6527 	 * tick of rounding and 1 extra tick because of +-1/2 tick
6528 	 * uncertainty in the firing of the timer.  The bias will give us
6529 	 * exactly the 1.5 tick we need.  But, because the bias is
6530 	 * statistical, we have to test that we don't drop below the minimum
6531 	 * feasible timer (which is 2 ticks).
6532 	 */
6533 	TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
6534 	    max(MSEC_2_TICKS(bbr->r_ctl.rc_min_rto_ms), rtt_ticks + 2),
6535 	    MSEC_2_TICKS(((uint32_t)bbr->rc_max_rto_sec) * 1000));
6536 
6537 	/*
6538 	 * We received an ack for a packet that wasn't retransmitted; it is
6539 	 * probably safe to discard any error indications we've received
6540 	 * recently.  This isn't quite right, but close enough for now (a
6541 	 * route might have failed after we sent a segment, and the return
6542 	 * path might not be symmetrical).
6543 	 */
6544 	tp->t_softerror = 0;
6545 	rtt = (TICKS_2_USEC(bbr->rc_tp->t_srtt) >> TCP_RTT_SHIFT);
6546 	if (bbr->r_ctl.bbr_smallest_srtt_this_state > rtt)
6547 		bbr->r_ctl.bbr_smallest_srtt_this_state = rtt;
6548 }
6549 
6550 static void
6551 bbr_earlier_retran(struct tcpcb *tp, struct tcp_bbr *bbr, struct bbr_sendmap *rsm,
6552 		   uint32_t t, uint32_t cts, int ack_type)
6553 {
6554 	/*
6555 	 * For this RSM, we acknowledged the data from a previous
6556 	 * transmission, not the last one we made. This means we did a false
6557 	 * retransmit.
6558 	 */
6559 	if (rsm->r_flags & BBR_HAS_FIN) {
6560 		/*
6561 		 * The sending of the FIN often is multiple sent when we
6562 		 * have everything outstanding ack'd. We ignore this case
6563 		 * since its over now.
6564 		 */
6565 		return;
6566 	}
6567 	if (rsm->r_flags & BBR_TLP) {
6568 		/*
6569 		 * We expect TLP's to have this occur often
6570 		 */
6571 		bbr->rc_tlp_rtx_out = 0;
6572 		return;
6573 	}
6574 	if (ack_type != BBR_CUM_ACKED) {
6575 		/*
6576 		 * If it was not a cum-ack we
6577 		 * don't really know for sure since
6578 		 * the timestamp could be from some
6579 		 * other transmission.
6580 		 */
6581 		return;
6582 	}
6583 
6584 	if (rsm->r_flags & BBR_WAS_SACKPASS) {
6585 		/*
6586 		 * We retransmitted based on a sack and the earlier
6587 		 * retransmission ack'd it - re-ordering is occuring.
6588 		 */
6589 		BBR_STAT_INC(bbr_reorder_seen);
6590 		bbr->r_ctl.rc_reorder_ts = cts;
6591 	}
6592 	/* Back down the loss count */
6593 	if (rsm->r_flags & BBR_MARKED_LOST) {
6594 		bbr->r_ctl.rc_lost -= rsm->r_end - rsm->r_start;
6595 		bbr->r_ctl.rc_lost_bytes -= rsm->r_end - rsm->r_start;
6596 		rsm->r_flags &= ~BBR_MARKED_LOST;
6597 		if (SEQ_GT(bbr->r_ctl.rc_lt_lost, bbr->r_ctl.rc_lost))
6598 			/* LT sampling also needs adjustment */
6599 			bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
6600 	}
6601 	/***** RRS HERE ************************/
6602 	/* Do we need to do this???            */
6603 	/* bbr_reset_lt_bw_sampling(bbr, cts); */
6604 	/***** RRS HERE ************************/
6605 	BBR_STAT_INC(bbr_badfr);
6606 	BBR_STAT_ADD(bbr_badfr_bytes, (rsm->r_end - rsm->r_start));
6607 }
6608 
6609 
6610 static void
6611 bbr_set_reduced_rtt(struct tcp_bbr *bbr, uint32_t cts, uint32_t line)
6612 {
6613 	bbr->r_ctl.rc_rtt_shrinks = cts;
6614 	if (bbr_can_force_probertt &&
6615 	    (TSTMP_GT(cts, bbr->r_ctl.last_in_probertt)) &&
6616 	    ((cts - bbr->r_ctl.last_in_probertt) > bbr->r_ctl.rc_probertt_int)) {
6617 		/*
6618 		 * We should enter probe-rtt its been too long
6619 		 * since we have been there.
6620 		 */
6621 		bbr_enter_probe_rtt(bbr, cts, __LINE__);
6622 	} else
6623 		bbr_check_probe_rtt_limits(bbr, cts);
6624 }
6625 
6626 static void
6627 tcp_bbr_commit_bw(struct tcp_bbr *bbr, uint32_t cts)
6628 {
6629 	uint64_t orig_bw;
6630 
6631 	if (bbr->r_ctl.rc_bbr_cur_del_rate == 0) {
6632 		/* We never apply a zero measurment */
6633 		bbr_log_type_bbrupd(bbr, 20, cts, 0, 0,
6634 				    0, 0, 0, 0, 0, 0);
6635 		return;
6636 	}
6637 	if (bbr->r_ctl.r_measurement_count < 0xffffffff)
6638 		bbr->r_ctl.r_measurement_count++;
6639 	orig_bw = get_filter_value(&bbr->r_ctl.rc_delrate);
6640 	apply_filter_max(&bbr->r_ctl.rc_delrate, bbr->r_ctl.rc_bbr_cur_del_rate, bbr->r_ctl.rc_pkt_epoch);
6641 	bbr_log_type_bbrupd(bbr, 21, cts, (uint32_t)orig_bw,
6642 			    (uint32_t)get_filter_value(&bbr->r_ctl.rc_delrate),
6643 			    0, 0, 0, 0, 0, 0);
6644 	if (orig_bw &&
6645 	    (orig_bw != get_filter_value(&bbr->r_ctl.rc_delrate))) {
6646 		if (bbr->bbr_hdrw_pacing) {
6647 			/*
6648 			 * Apply a new rate to the hardware
6649 			 * possibly.
6650 			 */
6651 			bbr_update_hardware_pacing_rate(bbr, cts);
6652 		}
6653 		bbr_set_state_target(bbr, __LINE__);
6654 		tcp_bbr_tso_size_check(bbr, cts);
6655 		if (bbr->r_recovery_bw)  {
6656 			bbr_setup_red_bw(bbr, cts);
6657 			bbr_log_type_bw_reduce(bbr, BBR_RED_BW_USELRBW);
6658 		}
6659 	} else if ((orig_bw == 0) && get_filter_value(&bbr->r_ctl.rc_delrate))
6660 		tcp_bbr_tso_size_check(bbr, cts);
6661 }
6662 
6663 static void
6664 bbr_nf_measurement(struct tcp_bbr *bbr, struct bbr_sendmap *rsm, uint32_t rtt, uint32_t cts)
6665 {
6666 	if (bbr->rc_in_persist == 0) {
6667 		/* We log only when not in persist */
6668 		/* Translate to a Bytes Per Second */
6669 		uint64_t tim, bw, ts_diff, ts_bw;
6670 		uint32_t upper, lower, delivered;
6671 
6672 		if (TSTMP_GT(bbr->r_ctl.rc_del_time, rsm->r_del_time))
6673 			tim = (uint64_t)(bbr->r_ctl.rc_del_time - rsm->r_del_time);
6674 		else
6675 			tim = 1;
6676 		/*
6677 		 * Now that we have processed the tim (skipping the sample
6678 		 * or possibly updating the time, go ahead and
6679 		 * calculate the cdr.
6680 		 */
6681 		delivered = (bbr->r_ctl.rc_delivered - rsm->r_delivered);
6682 		bw = (uint64_t)delivered;
6683 		bw *= (uint64_t)USECS_IN_SECOND;
6684 		bw /= tim;
6685 		if (bw == 0) {
6686 			/* We must have a calculatable amount */
6687 			return;
6688 		}
6689 		upper = (bw >> 32) & 0x00000000ffffffff;
6690 		lower = bw & 0x00000000ffffffff;
6691 		/*
6692 		 * If we are using this b/w shove it in now so we
6693 		 * can see in the trace viewer if it gets over-ridden.
6694 		 */
6695 		if (rsm->r_ts_valid &&
6696 		    bbr->rc_ts_valid &&
6697 		    bbr->rc_ts_clock_set &&
6698 		    (bbr->rc_ts_cant_be_used == 0) &&
6699 		    bbr->rc_use_ts_limit) {
6700 			ts_diff = max((bbr->r_ctl.last_inbound_ts - rsm->r_del_ack_ts), 1);
6701 			ts_diff *= bbr->r_ctl.bbr_peer_tsratio;
6702 			if ((delivered == 0) ||
6703 			    (rtt < 1000)) {
6704 				/* Can't use the ts */
6705 				bbr_log_type_bbrupd(bbr, 61, cts,
6706 						    ts_diff,
6707 						    bbr->r_ctl.last_inbound_ts,
6708 						    rsm->r_del_ack_ts, 0,
6709 						    0, 0, 0, delivered);
6710 			} else {
6711 				ts_bw = (uint64_t)delivered;
6712 				ts_bw *= (uint64_t)USECS_IN_SECOND;
6713 				ts_bw /= ts_diff;
6714 				bbr_log_type_bbrupd(bbr, 62, cts,
6715 						    (ts_bw >> 32),
6716 						    (ts_bw & 0xffffffff), 0, 0,
6717 						    0, 0, ts_diff, delivered);
6718 				if ((bbr->ts_can_raise) &&
6719 				    (ts_bw > bw)) {
6720 					bbr_log_type_bbrupd(bbr, 8, cts,
6721 							    delivered,
6722 							    ts_diff,
6723 							    (bw >> 32),
6724 							    (bw & 0x00000000ffffffff),
6725 							    0, 0, 0, 0);
6726 					bw = ts_bw;
6727 				} else if (ts_bw && (ts_bw < bw)) {
6728 					bbr_log_type_bbrupd(bbr, 7, cts,
6729 							    delivered,
6730 							    ts_diff,
6731 							    (bw >> 32),
6732 							    (bw & 0x00000000ffffffff),
6733 							    0, 0, 0, 0);
6734 					bw = ts_bw;
6735 				}
6736 			}
6737 		}
6738 		if (rsm->r_first_sent_time &&
6739 		    TSTMP_GT(rsm->r_tim_lastsent[(rsm->r_rtr_cnt -1)],rsm->r_first_sent_time)) {
6740 			uint64_t sbw, sti;
6741 			/*
6742 			 * We use what was in flight at the time of our
6743 			 * send  and the size of this send to figure
6744 			 * out what we have been sending at (amount).
6745 			 * For the time we take from the time of
6746 			 * the send of the first send outstanding
6747 			 * until this send plus this sends pacing
6748 			 * time. This gives us a good calculation
6749 			 * as to the rate we have been sending at.
6750 			 */
6751 
6752 			sbw = (uint64_t)(rsm->r_flight_at_send);
6753 			sbw *= (uint64_t)USECS_IN_SECOND;
6754 			sti = rsm->r_tim_lastsent[(rsm->r_rtr_cnt -1)] - rsm->r_first_sent_time;
6755 			sti += rsm->r_pacing_delay;
6756 			sbw /= sti;
6757 			if (sbw < bw) {
6758 				bbr_log_type_bbrupd(bbr, 6, cts,
6759 						    delivered,
6760 						    (uint32_t)sti,
6761 						    (bw >> 32),
6762 						    (uint32_t)bw,
6763 						    rsm->r_first_sent_time, 0, (sbw >> 32),
6764 						    (uint32_t)sbw);
6765 				bw = sbw;
6766 			}
6767 		}
6768 		/* Use the google algorithm for b/w measurements */
6769 		bbr->r_ctl.rc_bbr_cur_del_rate = bw;
6770 		if ((rsm->r_app_limited == 0) ||
6771 		    (bw > get_filter_value(&bbr->r_ctl.rc_delrate))) {
6772 			tcp_bbr_commit_bw(bbr, cts);
6773 			bbr_log_type_bbrupd(bbr, 10, cts, (uint32_t)tim, delivered,
6774 					    0, 0, 0, 0,  bbr->r_ctl.rc_del_time,  rsm->r_del_time);
6775 		}
6776 	}
6777 }
6778 
6779 static void
6780 bbr_google_measurement(struct tcp_bbr *bbr, struct bbr_sendmap *rsm, uint32_t rtt, uint32_t cts)
6781 {
6782 	if (bbr->rc_in_persist == 0) {
6783 		/* We log only when not in persist */
6784 		/* Translate to a Bytes Per Second */
6785 		uint64_t tim, bw;
6786 		uint32_t upper, lower, delivered;
6787 		int no_apply = 0;
6788 
6789 		if (TSTMP_GT(bbr->r_ctl.rc_del_time, rsm->r_del_time))
6790 			tim = (uint64_t)(bbr->r_ctl.rc_del_time - rsm->r_del_time);
6791 		else
6792 			tim = 1;
6793 		/*
6794 		 * Now that we have processed the tim (skipping the sample
6795 		 * or possibly updating the time, go ahead and
6796 		 * calculate the cdr.
6797 		 */
6798 		delivered = (bbr->r_ctl.rc_delivered - rsm->r_delivered);
6799 		bw = (uint64_t)delivered;
6800 		bw *= (uint64_t)USECS_IN_SECOND;
6801 		bw /= tim;
6802 		if (tim < bbr->r_ctl.rc_lowest_rtt) {
6803 			bbr_log_type_bbrupd(bbr, 99, cts, (uint32_t)tim, delivered,
6804 					    tim, bbr->r_ctl.rc_lowest_rtt, 0, 0, 0, 0);
6805 
6806 			no_apply = 1;
6807 		}
6808 		upper = (bw >> 32) & 0x00000000ffffffff;
6809 		lower = bw & 0x00000000ffffffff;
6810 		/*
6811 		 * If we are using this b/w shove it in now so we
6812 		 * can see in the trace viewer if it gets over-ridden.
6813 		 */
6814 		bbr->r_ctl.rc_bbr_cur_del_rate = bw;
6815 		/* Gate by the sending rate */
6816 		if (rsm->r_first_sent_time &&
6817 		    TSTMP_GT(rsm->r_tim_lastsent[(rsm->r_rtr_cnt -1)],rsm->r_first_sent_time)) {
6818 			uint64_t sbw, sti;
6819 			/*
6820 			 * We use what was in flight at the time of our
6821 			 * send  and the size of this send to figure
6822 			 * out what we have been sending at (amount).
6823 			 * For the time we take from the time of
6824 			 * the send of the first send outstanding
6825 			 * until this send plus this sends pacing
6826 			 * time. This gives us a good calculation
6827 			 * as to the rate we have been sending at.
6828 			 */
6829 
6830 			sbw = (uint64_t)(rsm->r_flight_at_send);
6831 			sbw *= (uint64_t)USECS_IN_SECOND;
6832 			sti = rsm->r_tim_lastsent[(rsm->r_rtr_cnt -1)] - rsm->r_first_sent_time;
6833 			sti += rsm->r_pacing_delay;
6834 			sbw /= sti;
6835 			if (sbw < bw) {
6836 				bbr_log_type_bbrupd(bbr, 6, cts,
6837 						    delivered,
6838 						    (uint32_t)sti,
6839 						    (bw >> 32),
6840 						    (uint32_t)bw,
6841 						    rsm->r_first_sent_time, 0, (sbw >> 32),
6842 						    (uint32_t)sbw);
6843 				bw = sbw;
6844 			}
6845 			if ((sti > tim) &&
6846 			    (sti < bbr->r_ctl.rc_lowest_rtt)) {
6847 				bbr_log_type_bbrupd(bbr, 99, cts, (uint32_t)tim, delivered,
6848 						    (uint32_t)sti, bbr->r_ctl.rc_lowest_rtt, 0, 0, 0, 0);
6849 				no_apply = 1;
6850 			} else
6851 				no_apply = 0;
6852 		}
6853 		bbr->r_ctl.rc_bbr_cur_del_rate = bw;
6854 		if ((no_apply == 0) &&
6855 		    ((rsm->r_app_limited == 0) ||
6856 		     (bw > get_filter_value(&bbr->r_ctl.rc_delrate)))) {
6857 			tcp_bbr_commit_bw(bbr, cts);
6858 			bbr_log_type_bbrupd(bbr, 10, cts, (uint32_t)tim, delivered,
6859 					    0, 0, 0, 0, bbr->r_ctl.rc_del_time,  rsm->r_del_time);
6860 		}
6861 	}
6862 }
6863 
6864 
6865 static void
6866 bbr_update_bbr_info(struct tcp_bbr *bbr, struct bbr_sendmap *rsm, uint32_t rtt, uint32_t cts, uint32_t tsin,
6867     uint32_t uts, int32_t match, uint32_t rsm_send_time, int32_t ack_type, struct tcpopt *to)
6868 {
6869 	uint64_t old_rttprop;
6870 
6871 	/* Update our delivery time and amount */
6872 	bbr->r_ctl.rc_delivered += (rsm->r_end - rsm->r_start);
6873 	bbr->r_ctl.rc_del_time = cts;
6874 	if (rtt == 0) {
6875 		/*
6876 		 * 0 means its a retransmit, for now we don't use these for
6877 		 * the rest of BBR.
6878 		 */
6879 		return;
6880 	}
6881 	if ((bbr->rc_use_google == 0) &&
6882 	    (match != BBR_RTT_BY_EXACTMATCH) &&
6883 	    (match != BBR_RTT_BY_TIMESTAMP)){
6884 		/*
6885 		 * We get a lot of rtt updates, lets not pay attention to
6886 		 * any that are not an exact match. That way we don't have
6887 		 * to worry about timestamps and the whole nonsense of
6888 		 * unsure if its a retransmission etc (if we ever had the
6889 		 * timestamp fixed to always have the last thing sent this
6890 		 * would not be a issue).
6891 		 */
6892 		return;
6893 	}
6894 	if ((bbr_no_retran && bbr->rc_use_google) &&
6895 	    (match != BBR_RTT_BY_EXACTMATCH) &&
6896 	    (match != BBR_RTT_BY_TIMESTAMP)){
6897 		/*
6898 		 * We only do measurements in google mode
6899 		 * with bbr_no_retran on for sure things.
6900 		 */
6901 		return;
6902 	}
6903 	/* Only update srtt if we know by exact match */
6904 	tcp_bbr_xmit_timer(bbr, rtt, rsm_send_time, rsm->r_start, tsin);
6905 	if (ack_type == BBR_CUM_ACKED)
6906 		bbr->rc_ack_is_cumack = 1;
6907 	else
6908 		bbr->rc_ack_is_cumack = 0;
6909 	old_rttprop = bbr_get_rtt(bbr, BBR_RTT_PROP);
6910         /*
6911 	 * Note the following code differs to the original
6912 	 * BBR spec. It calls for <= not <. However after a
6913 	 * long discussion in email with Neal, he acknowledged
6914 	 * that it should be < than so that we will have flows
6915 	 * going into probe-rtt (we were seeing cases where that
6916 	 * did not happen and caused ugly things to occur). We
6917 	 * have added this agreed upon fix to our code base.
6918 	 */
6919 	if (rtt < old_rttprop) {
6920 		/* Update when we last saw a rtt drop */
6921 		bbr_log_rtt_shrinks(bbr, cts, 0, rtt, __LINE__, BBR_RTTS_NEWRTT, 0);
6922 		bbr_set_reduced_rtt(bbr, cts, __LINE__);
6923 	}
6924 	bbr_log_type_bbrrttprop(bbr, rtt, (rsm ? rsm->r_end : 0), uts, cts,
6925 	    match, rsm->r_start, rsm->r_flags);
6926 	apply_filter_min_small(&bbr->r_ctl.rc_rttprop, rtt, cts);
6927 	if (old_rttprop != bbr_get_rtt(bbr, BBR_RTT_PROP)) {
6928 		/*
6929 		 * The RTT-prop moved, reset the target (may be a
6930 		 * nop for some states).
6931 		 */
6932 		bbr_set_state_target(bbr, __LINE__);
6933 		if (bbr->rc_bbr_state == BBR_STATE_PROBE_RTT)
6934 			bbr_log_rtt_shrinks(bbr, cts, 0, 0,
6935 					    __LINE__, BBR_RTTS_NEW_TARGET, 0);
6936 		else if (old_rttprop < bbr_get_rtt(bbr, BBR_RTT_PROP))
6937 			/* It went up */
6938 			bbr_check_probe_rtt_limits(bbr, cts);
6939 	}
6940 	if ((bbr->rc_use_google == 0) &&
6941 	    (match == BBR_RTT_BY_TIMESTAMP)) {
6942 		/*
6943 		 * We don't do b/w update with
6944 		 * these since they are not really
6945 		 * reliable.
6946 		 */
6947 		return;
6948 	}
6949 	if (bbr->r_ctl.r_app_limited_until &&
6950 	    (bbr->r_ctl.rc_delivered >= bbr->r_ctl.r_app_limited_until)) {
6951 		/* We are no longer app-limited */
6952 		bbr->r_ctl.r_app_limited_until = 0;
6953 	}
6954 	if (bbr->rc_use_google) {
6955 		bbr_google_measurement(bbr, rsm, rtt, cts);
6956 	} else {
6957 		bbr_nf_measurement(bbr, rsm, rtt, cts);
6958 	}
6959 }
6960 
6961 /*
6962  * Convert a timestamp that the main stack
6963  * uses (milliseconds) into one that bbr uses
6964  * (microseconds). Return that converted timestamp.
6965  */
6966 static uint32_t
6967 bbr_ts_convert(uint32_t cts) {
6968 	uint32_t sec, msec;
6969 
6970 	sec = cts / MS_IN_USEC;
6971 	msec = cts - (MS_IN_USEC * sec);
6972 	return ((sec * USECS_IN_SECOND) + (msec * MS_IN_USEC));
6973 }
6974 
6975 /*
6976  * Return 0 if we did not update the RTT time, return
6977  * 1 if we did.
6978  */
6979 static int
6980 bbr_update_rtt(struct tcpcb *tp, struct tcp_bbr *bbr,
6981     struct bbr_sendmap *rsm, struct tcpopt *to, uint32_t cts, int32_t ack_type, uint32_t th_ack)
6982 {
6983 	int32_t i;
6984 	uint32_t t, uts = 0;
6985 
6986 	if ((rsm->r_flags & BBR_ACKED) ||
6987 	    (rsm->r_flags & BBR_WAS_RENEGED) ||
6988 	    (rsm->r_flags & BBR_RXT_CLEARED)) {
6989 		/* Already done */
6990 		return (0);
6991 	}
6992 	if (rsm->r_rtr_cnt == 1) {
6993 		/*
6994 		 * Only one transmit. Hopefully the normal case.
6995 		 */
6996 		if (TSTMP_GT(cts, rsm->r_tim_lastsent[0]))
6997 			t = cts - rsm->r_tim_lastsent[0];
6998 		else
6999 			t = 1;
7000 		if ((int)t <= 0)
7001 			t = 1;
7002 		bbr->r_ctl.rc_last_rtt = t;
7003 		bbr_update_bbr_info(bbr, rsm, t, cts, to->to_tsecr, 0,
7004 				    BBR_RTT_BY_EXACTMATCH, rsm->r_tim_lastsent[0], ack_type, to);
7005 		return (1);
7006 	}
7007 	/* Convert to usecs */
7008 	if ((bbr_can_use_ts_for_rtt == 1) &&
7009 	    (bbr->rc_use_google == 1) &&
7010 	    (ack_type == BBR_CUM_ACKED) &&
7011 	    (to->to_flags & TOF_TS) &&
7012 	    (to->to_tsecr != 0)) {
7013 
7014 		t = tcp_tv_to_mssectick(&bbr->rc_tv) - to->to_tsecr;
7015 		if (t < 1)
7016 			t = 1;
7017 		t *= MS_IN_USEC;
7018 		bbr_update_bbr_info(bbr, rsm, t, cts, to->to_tsecr, 0,
7019 				    BBR_RTT_BY_TIMESTAMP,
7020 				    rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)],
7021 				    ack_type, to);
7022 		return (1);
7023 	}
7024 	uts = bbr_ts_convert(to->to_tsecr);
7025 	if ((to->to_flags & TOF_TS) &&
7026 	    (to->to_tsecr != 0) &&
7027 	    (ack_type == BBR_CUM_ACKED) &&
7028 	    ((rsm->r_flags & BBR_OVERMAX) == 0)) {
7029 		/*
7030 		 * Now which timestamp does it match? In this block the ACK
7031 		 * may be coming from a previous transmission.
7032 		 */
7033 		uint32_t fudge;
7034 
7035 		fudge = BBR_TIMER_FUDGE;
7036 		for (i = 0; i < rsm->r_rtr_cnt; i++) {
7037 			if ((SEQ_GEQ(uts, (rsm->r_tim_lastsent[i] - fudge))) &&
7038 			    (SEQ_LEQ(uts, (rsm->r_tim_lastsent[i] + fudge)))) {
7039 				if (TSTMP_GT(cts, rsm->r_tim_lastsent[i]))
7040 					t = cts - rsm->r_tim_lastsent[i];
7041 				else
7042 					t = 1;
7043 				if ((int)t <= 0)
7044 					t = 1;
7045 				bbr->r_ctl.rc_last_rtt = t;
7046 				bbr_update_bbr_info(bbr, rsm, t, cts, to->to_tsecr, uts, BBR_RTT_BY_TSMATCHING,
7047 						    rsm->r_tim_lastsent[i], ack_type, to);
7048 				if ((i + 1) < rsm->r_rtr_cnt) {
7049 					/* Likely */
7050 					bbr_earlier_retran(tp, bbr, rsm, t, cts, ack_type);
7051 				} else if (rsm->r_flags & BBR_TLP) {
7052 					bbr->rc_tlp_rtx_out = 0;
7053 				}
7054 				return (1);
7055 			}
7056 		}
7057 		/* Fall through if we can't find a matching timestamp */
7058 	}
7059 	/*
7060 	 * Ok its a SACK block that we retransmitted. or a windows
7061 	 * machine without timestamps. We can tell nothing from the
7062 	 * time-stamp since its not there or the time the peer last
7063 	 * recieved a segment that moved forward its cum-ack point.
7064 	 *
7065 	 * Lets look at the last retransmit and see what we can tell
7066 	 * (with BBR for space we only keep 2 note we have to keep
7067 	 * at least 2 so the map can not be condensed more).
7068 	 */
7069 	i = rsm->r_rtr_cnt - 1;
7070 	if (TSTMP_GT(cts, rsm->r_tim_lastsent[i]))
7071 		t = cts - rsm->r_tim_lastsent[i];
7072 	else
7073 		goto not_sure;
7074 	if (t < bbr->r_ctl.rc_lowest_rtt) {
7075 		/*
7076 		 * We retransmitted and the ack came back in less
7077 		 * than the smallest rtt we have observed in the
7078 		 * windowed rtt. We most likey did an improper
7079 		 * retransmit as outlined in 4.2 Step 3 point 2 in
7080 		 * the rack-draft.
7081 		 *
7082 		 * Use the prior transmission to update all the
7083 		 * information as long as there is only one prior
7084 		 * transmission.
7085 		 */
7086 		if ((rsm->r_flags & BBR_OVERMAX) == 0) {
7087 #ifdef BBR_INVARIANTS
7088 			if (rsm->r_rtr_cnt == 1)
7089 				panic("rsm:%p bbr:%p rsm has overmax and only 1 retranmit flags:%x?", rsm, bbr, rsm->r_flags);
7090 #endif
7091 			i = rsm->r_rtr_cnt - 2;
7092 			if (TSTMP_GT(cts, rsm->r_tim_lastsent[i]))
7093 				t = cts - rsm->r_tim_lastsent[i];
7094 			else
7095 				t = 1;
7096 			bbr_update_bbr_info(bbr, rsm, t, cts, to->to_tsecr, uts, BBR_RTT_BY_EARLIER_RET,
7097 					    rsm->r_tim_lastsent[i], ack_type, to);
7098 			bbr_earlier_retran(tp, bbr, rsm, t, cts, ack_type);
7099 		} else {
7100 			/*
7101 			 * Too many prior transmissions, just
7102 			 * updated BBR delivered
7103 			 */
7104 not_sure:
7105 			bbr_update_bbr_info(bbr, rsm, 0, cts, to->to_tsecr, uts,
7106 					    BBR_RTT_BY_SOME_RETRAN, 0, ack_type, to);
7107 		}
7108 	} else {
7109 		/*
7110 		 * We retransmitted it and the retransmit did the
7111 		 * job.
7112 		 */
7113 		if (rsm->r_flags & BBR_TLP)
7114 			bbr->rc_tlp_rtx_out = 0;
7115 		if ((rsm->r_flags & BBR_OVERMAX) == 0)
7116 			bbr_update_bbr_info(bbr, rsm, t, cts, to->to_tsecr, uts,
7117 					    BBR_RTT_BY_THIS_RETRAN, 0, ack_type, to);
7118 		else
7119 			bbr_update_bbr_info(bbr, rsm, 0, cts, to->to_tsecr, uts,
7120 					    BBR_RTT_BY_SOME_RETRAN, 0, ack_type, to);
7121 		return (1);
7122 	}
7123 	return (0);
7124 }
7125 
7126 /*
7127  * Mark the SACK_PASSED flag on all entries prior to rsm send wise.
7128  */
7129 static void
7130 bbr_log_sack_passed(struct tcpcb *tp,
7131     struct tcp_bbr *bbr, struct bbr_sendmap *rsm)
7132 {
7133 	struct bbr_sendmap *nrsm;
7134 
7135 	nrsm = rsm;
7136 	TAILQ_FOREACH_REVERSE_FROM(nrsm, &bbr->r_ctl.rc_tmap,
7137 	    bbr_head, r_tnext) {
7138 		if (nrsm == rsm) {
7139 			/* Skip orginal segment he is acked */
7140 			continue;
7141 		}
7142 		if (nrsm->r_flags & BBR_ACKED) {
7143 			/* Skip ack'd segments */
7144 			continue;
7145 		}
7146 		if (nrsm->r_flags & BBR_SACK_PASSED) {
7147 			/*
7148 			 * We found one that is already marked
7149 			 * passed, we have been here before and
7150 			 * so all others below this are marked.
7151 			 */
7152 			break;
7153 		}
7154 		BBR_STAT_INC(bbr_sack_passed);
7155 		nrsm->r_flags |= BBR_SACK_PASSED;
7156 		if (((nrsm->r_flags & BBR_MARKED_LOST) == 0) &&
7157 		    bbr_is_lost(bbr, nrsm, bbr->r_ctl.rc_rcvtime)) {
7158 			bbr->r_ctl.rc_lost += nrsm->r_end - nrsm->r_start;
7159 			bbr->r_ctl.rc_lost_bytes += nrsm->r_end - nrsm->r_start;
7160 			nrsm->r_flags |= BBR_MARKED_LOST;
7161 		}
7162 		nrsm->r_flags &= ~BBR_WAS_SACKPASS;
7163 	}
7164 }
7165 
7166 /*
7167  * Returns the number of bytes that were
7168  * newly ack'd by sack blocks.
7169  */
7170 static uint32_t
7171 bbr_proc_sack_blk(struct tcpcb *tp, struct tcp_bbr *bbr, struct sackblk *sack,
7172     struct tcpopt *to, struct bbr_sendmap **prsm, uint32_t cts)
7173 {
7174 	int32_t times = 0;
7175 	uint32_t start, end, maxseg, changed = 0;
7176 	struct bbr_sendmap *rsm, *nrsm;
7177 	int32_t used_ref = 1;
7178 	uint8_t went_back = 0, went_fwd = 0;
7179 
7180 	maxseg = tp->t_maxseg - bbr->rc_last_options;
7181 	start = sack->start;
7182 	end = sack->end;
7183 	rsm = *prsm;
7184 	if (rsm == NULL)
7185 		used_ref = 0;
7186 
7187 	/* Do we locate the block behind where we last were? */
7188 	if (rsm && SEQ_LT(start, rsm->r_start)) {
7189 		went_back = 1;
7190 		TAILQ_FOREACH_REVERSE_FROM(rsm, &bbr->r_ctl.rc_map, bbr_head, r_next) {
7191 			if (SEQ_GEQ(start, rsm->r_start) &&
7192 			    SEQ_LT(start, rsm->r_end)) {
7193 				goto do_rest_ofb;
7194 			}
7195 		}
7196 	}
7197 start_at_beginning:
7198 	went_fwd = 1;
7199 	/*
7200 	 * Ok lets locate the block where this guy is fwd from rsm (if its
7201 	 * set)
7202 	 */
7203 	TAILQ_FOREACH_FROM(rsm, &bbr->r_ctl.rc_map, r_next) {
7204 		if (SEQ_GEQ(start, rsm->r_start) &&
7205 		    SEQ_LT(start, rsm->r_end)) {
7206 			break;
7207 		}
7208 	}
7209 do_rest_ofb:
7210 	if (rsm == NULL) {
7211 		/*
7212 		 * This happens when we get duplicate sack blocks with the
7213 		 * same end. For example SACK 4: 100 SACK 3: 100 The sort
7214 		 * will not change there location so we would just start at
7215 		 * the end of the first one and get lost.
7216 		 */
7217 		if (tp->t_flags & TF_SENTFIN) {
7218 			/*
7219 			 * Check to see if we have not logged the FIN that
7220 			 * went out.
7221 			 */
7222 			nrsm = TAILQ_LAST_FAST(&bbr->r_ctl.rc_map, bbr_sendmap, r_next);
7223 			if (nrsm && (nrsm->r_end + 1) == tp->snd_max) {
7224 				/*
7225 				 * Ok we did not get the FIN logged.
7226 				 */
7227 				nrsm->r_end++;
7228 				rsm = nrsm;
7229 				goto do_rest_ofb;
7230 			}
7231 		}
7232 		if (times == 1) {
7233 #ifdef BBR_INVARIANTS
7234 			panic("tp:%p bbr:%p sack:%p to:%p prsm:%p",
7235 			    tp, bbr, sack, to, prsm);
7236 #else
7237 			goto out;
7238 #endif
7239 		}
7240 		times++;
7241 		BBR_STAT_INC(bbr_sack_proc_restart);
7242 		rsm = NULL;
7243 		goto start_at_beginning;
7244 	}
7245 	/* Ok we have an ACK for some piece of rsm */
7246 	if (rsm->r_start != start) {
7247 		/*
7248 		 * Need to split this in two pieces the before and after.
7249 		 */
7250 		if (bbr_sack_mergable(rsm, start, end))
7251 			nrsm = bbr_alloc_full_limit(bbr);
7252 		else
7253 			nrsm = bbr_alloc_limit(bbr, BBR_LIMIT_TYPE_SPLIT);
7254 		if (nrsm == NULL) {
7255 			/* We could not allocate ignore the sack */
7256 			struct sackblk blk;
7257 
7258 			blk.start = start;
7259 			blk.end = end;
7260 			sack_filter_reject(&bbr->r_ctl.bbr_sf, &blk);
7261 			goto out;
7262 		}
7263 		bbr_clone_rsm(bbr, nrsm, rsm, start);
7264 		TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_map, rsm, nrsm, r_next);
7265 		if (rsm->r_in_tmap) {
7266 			TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
7267 			nrsm->r_in_tmap = 1;
7268 		}
7269 		rsm->r_flags &= (~BBR_HAS_FIN);
7270 		rsm = nrsm;
7271 	}
7272 	if (SEQ_GEQ(end, rsm->r_end)) {
7273 		/*
7274 		 * The end of this block is either beyond this guy or right
7275 		 * at this guy.
7276 		 */
7277 		if ((rsm->r_flags & BBR_ACKED) == 0) {
7278 			bbr_update_rtt(tp, bbr, rsm, to, cts, BBR_SACKED, 0);
7279 			changed += (rsm->r_end - rsm->r_start);
7280 			bbr->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start);
7281 			bbr_log_sack_passed(tp, bbr, rsm);
7282 			if (rsm->r_flags & BBR_MARKED_LOST) {
7283 				bbr->r_ctl.rc_lost_bytes -= rsm->r_end - rsm->r_start;
7284 			}
7285 			/* Is Reordering occuring? */
7286 			if (rsm->r_flags & BBR_SACK_PASSED) {
7287 				BBR_STAT_INC(bbr_reorder_seen);
7288 				bbr->r_ctl.rc_reorder_ts = cts;
7289 				if (rsm->r_flags & BBR_MARKED_LOST) {
7290 					bbr->r_ctl.rc_lost -= rsm->r_end - rsm->r_start;
7291 					if (SEQ_GT(bbr->r_ctl.rc_lt_lost, bbr->r_ctl.rc_lost))
7292 						/* LT sampling also needs adjustment */
7293 						bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
7294 				}
7295 			}
7296 			rsm->r_flags |= BBR_ACKED;
7297 			rsm->r_flags &= ~(BBR_TLP|BBR_WAS_RENEGED|BBR_RXT_CLEARED|BBR_MARKED_LOST);
7298 			if (rsm->r_in_tmap) {
7299 				TAILQ_REMOVE(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
7300 				rsm->r_in_tmap = 0;
7301 			}
7302 		}
7303 		bbr_isit_a_pkt_epoch(bbr, cts, rsm, __LINE__, BBR_SACKED);
7304 		if (end == rsm->r_end) {
7305 			/* This block only - done */
7306 			goto out;
7307 		}
7308 		/* There is more not coverend by this rsm move on */
7309 		start = rsm->r_end;
7310 		nrsm = TAILQ_NEXT(rsm, r_next);
7311 		rsm = nrsm;
7312 		times = 0;
7313 		goto do_rest_ofb;
7314 	}
7315 	if (rsm->r_flags & BBR_ACKED) {
7316 		/* Been here done that */
7317 		goto out;
7318 	}
7319 	/* Ok we need to split off this one at the tail */
7320 	if (bbr_sack_mergable(rsm, start, end))
7321 		nrsm = bbr_alloc_full_limit(bbr);
7322 	else
7323 		nrsm = bbr_alloc_limit(bbr, BBR_LIMIT_TYPE_SPLIT);
7324 	if (nrsm == NULL) {
7325 		/* failed XXXrrs what can we do but loose the sack info? */
7326 		struct sackblk blk;
7327 
7328 		blk.start = start;
7329 		blk.end = end;
7330 		sack_filter_reject(&bbr->r_ctl.bbr_sf, &blk);
7331 		goto out;
7332 	}
7333 	/* Clone it */
7334 	bbr_clone_rsm(bbr, nrsm, rsm, end);
7335 	/* The sack block does not cover this guy fully */
7336 	rsm->r_flags &= (~BBR_HAS_FIN);
7337 	TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_map, rsm, nrsm, r_next);
7338 	if (rsm->r_in_tmap) {
7339 		TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
7340 		nrsm->r_in_tmap = 1;
7341 	}
7342 	nrsm->r_dupack = 0;
7343 	bbr_update_rtt(tp, bbr, rsm, to, cts, BBR_SACKED, 0);
7344 	bbr_isit_a_pkt_epoch(bbr, cts, rsm, __LINE__, BBR_SACKED);
7345 	changed += (rsm->r_end - rsm->r_start);
7346 	bbr->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start);
7347 	bbr_log_sack_passed(tp, bbr, rsm);
7348 	/* Is Reordering occuring? */
7349 	if (rsm->r_flags & BBR_MARKED_LOST) {
7350 		bbr->r_ctl.rc_lost_bytes -= rsm->r_end - rsm->r_start;
7351 	}
7352 	if (rsm->r_flags & BBR_SACK_PASSED) {
7353 		BBR_STAT_INC(bbr_reorder_seen);
7354 		bbr->r_ctl.rc_reorder_ts = cts;
7355 		if (rsm->r_flags & BBR_MARKED_LOST) {
7356 			bbr->r_ctl.rc_lost -= rsm->r_end - rsm->r_start;
7357 			if (SEQ_GT(bbr->r_ctl.rc_lt_lost, bbr->r_ctl.rc_lost))
7358 				/* LT sampling also needs adjustment */
7359 				bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
7360 		}
7361 	}
7362 	rsm->r_flags &= ~(BBR_TLP|BBR_WAS_RENEGED|BBR_RXT_CLEARED|BBR_MARKED_LOST);
7363 	rsm->r_flags |= BBR_ACKED;
7364 	if (rsm->r_in_tmap) {
7365 		TAILQ_REMOVE(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
7366 		rsm->r_in_tmap = 0;
7367 	}
7368 out:
7369 	if (rsm && (rsm->r_flags & BBR_ACKED)) {
7370 		/*
7371 		 * Now can we merge this newly acked
7372 		 * block with either the previous or
7373 		 * next block?
7374 		 */
7375 		nrsm = TAILQ_NEXT(rsm, r_next);
7376 		if (nrsm &&
7377 		    (nrsm->r_flags & BBR_ACKED)) {
7378 			/* yep this and next can be merged */
7379 			rsm = bbr_merge_rsm(bbr, rsm, nrsm);
7380 		}
7381 		/* Now what about the previous? */
7382 		nrsm = TAILQ_PREV(rsm, bbr_head, r_next);
7383 		if (nrsm &&
7384 		    (nrsm->r_flags & BBR_ACKED)) {
7385 			/* yep the previous and this can be merged */
7386 			rsm = bbr_merge_rsm(bbr, nrsm, rsm);
7387 		}
7388 	}
7389 	if (used_ref == 0) {
7390 		BBR_STAT_INC(bbr_sack_proc_all);
7391 	} else {
7392 		BBR_STAT_INC(bbr_sack_proc_short);
7393 	}
7394 	if (went_fwd && went_back) {
7395 		BBR_STAT_INC(bbr_sack_search_both);
7396 	} else if (went_fwd) {
7397 		BBR_STAT_INC(bbr_sack_search_fwd);
7398 	} else if (went_back) {
7399 		BBR_STAT_INC(bbr_sack_search_back);
7400 	}
7401 	/* Save off where the next seq is */
7402 	if (rsm)
7403 		bbr->r_ctl.rc_sacklast = TAILQ_NEXT(rsm, r_next);
7404 	else
7405 		bbr->r_ctl.rc_sacklast = NULL;
7406 	*prsm = rsm;
7407 	return (changed);
7408 }
7409 
7410 
7411 static void inline
7412 bbr_peer_reneges(struct tcp_bbr *bbr, struct bbr_sendmap *rsm, tcp_seq th_ack)
7413 {
7414 	struct bbr_sendmap *tmap;
7415 
7416 	BBR_STAT_INC(bbr_reneges_seen);
7417 	tmap = NULL;
7418 	while (rsm && (rsm->r_flags & BBR_ACKED)) {
7419 		/* Its no longer sacked, mark it so */
7420 		uint32_t oflags;
7421 		bbr->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
7422 #ifdef BBR_INVARIANTS
7423 		if (rsm->r_in_tmap) {
7424 			panic("bbr:%p rsm:%p flags:0x%x in tmap?",
7425 			    bbr, rsm, rsm->r_flags);
7426 		}
7427 #endif
7428 		oflags = rsm->r_flags;
7429 		if (rsm->r_flags & BBR_MARKED_LOST) {
7430 			bbr->r_ctl.rc_lost -= rsm->r_end - rsm->r_start;
7431 			bbr->r_ctl.rc_lost_bytes -= rsm->r_end - rsm->r_start;
7432 			if (SEQ_GT(bbr->r_ctl.rc_lt_lost, bbr->r_ctl.rc_lost))
7433 				/* LT sampling also needs adjustment */
7434 				bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
7435 		}
7436 		rsm->r_flags &= ~(BBR_ACKED | BBR_SACK_PASSED | BBR_WAS_SACKPASS | BBR_MARKED_LOST);
7437 		rsm->r_flags |= BBR_WAS_RENEGED;
7438 		rsm->r_flags |= BBR_RXT_CLEARED;
7439 		bbr_log_type_rsmclear(bbr, bbr->r_ctl.rc_rcvtime, rsm, oflags, __LINE__);
7440 		/* Rebuild it into our tmap */
7441 		if (tmap == NULL) {
7442 			TAILQ_INSERT_HEAD(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
7443 			tmap = rsm;
7444 		} else {
7445 			TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, tmap, rsm, r_tnext);
7446 			tmap = rsm;
7447 		}
7448 		tmap->r_in_tmap = 1;
7449 		/*
7450 		 * XXXrrs Delivered? Should we do anything here?
7451 		 *
7452 		 * Of course we don't on a rxt timeout so maybe its ok that
7453 		 * we don't?
7454 		 *
7455 		 * For now lets not.
7456 		 */
7457 		rsm = TAILQ_NEXT(rsm, r_next);
7458 	}
7459 	/*
7460 	 * Now lets possibly clear the sack filter so we start recognizing
7461 	 * sacks that cover this area.
7462 	 */
7463 	sack_filter_clear(&bbr->r_ctl.bbr_sf, th_ack);
7464 }
7465 
7466 static void
7467 bbr_log_syn(struct tcpcb *tp, struct tcpopt *to)
7468 {
7469 	struct tcp_bbr *bbr;
7470 	struct bbr_sendmap *rsm;
7471 	uint32_t cts;
7472 
7473 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
7474 	cts = bbr->r_ctl.rc_rcvtime;
7475 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
7476 	if (rsm && (rsm->r_flags & BBR_HAS_SYN)) {
7477 		if ((rsm->r_end - rsm->r_start) <= 1) {
7478 			/* Log out the SYN completely */
7479 			bbr->r_ctl.rc_holes_rxt -= rsm->r_rtr_bytes;
7480 			rsm->r_rtr_bytes = 0;
7481 			TAILQ_REMOVE(&bbr->r_ctl.rc_map, rsm, r_next);
7482 			if (rsm->r_in_tmap) {
7483 				TAILQ_REMOVE(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
7484 				rsm->r_in_tmap = 0;
7485 			}
7486 			if (bbr->r_ctl.rc_next == rsm) {
7487 				/* scoot along the marker */
7488 				bbr->r_ctl.rc_next = TAILQ_FIRST(&bbr->r_ctl.rc_map);
7489 			}
7490 			if (to != NULL)
7491 				bbr_update_rtt(tp, bbr, rsm, to, cts, BBR_CUM_ACKED, 0);
7492 			bbr_free(bbr, rsm);
7493 		} else {
7494 			/* There is more (Fast open)? strip out SYN. */
7495 			rsm->r_flags &= ~BBR_HAS_SYN;
7496 			rsm->r_start++;
7497 		}
7498 	}
7499 }
7500 
7501 /*
7502  * Returns the number of bytes that were
7503  * acknowledged by SACK blocks.
7504  */
7505 
7506 static uint32_t
7507 bbr_log_ack(struct tcpcb *tp, struct tcpopt *to, struct tcphdr *th,
7508     uint32_t *prev_acked)
7509 {
7510 	uint32_t changed, last_seq, entered_recovery = 0;
7511 	struct tcp_bbr *bbr;
7512 	struct bbr_sendmap *rsm;
7513 	struct sackblk sack, sack_blocks[TCP_MAX_SACK + 1];
7514 	register uint32_t th_ack;
7515 	int32_t i, j, k, new_sb, num_sack_blks = 0;
7516 	uint32_t cts, acked, ack_point, sack_changed = 0;
7517 	uint32_t p_maxseg, maxseg, p_acked = 0;
7518 
7519 	INP_WLOCK_ASSERT(tp->t_inpcb);
7520 	if (th->th_flags & TH_RST) {
7521 		/* We don't log resets */
7522 		return (0);
7523 	}
7524 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
7525 	cts = bbr->r_ctl.rc_rcvtime;
7526 
7527 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
7528 	changed = 0;
7529 	maxseg = tp->t_maxseg - bbr->rc_last_options;
7530 	p_maxseg = min(bbr->r_ctl.rc_pace_max_segs, maxseg);
7531 	th_ack = th->th_ack;
7532 	if (SEQ_GT(th_ack, tp->snd_una)) {
7533 		acked = th_ack - tp->snd_una;
7534 		bbr_log_progress_event(bbr, tp, ticks, PROGRESS_UPDATE, __LINE__);
7535 		bbr->rc_tp->t_acktime = ticks;
7536 	} else
7537 		acked = 0;
7538 	if (SEQ_LEQ(th_ack, tp->snd_una)) {
7539 		/* Only sent here for sack processing */
7540 		goto proc_sack;
7541 	}
7542 	if (rsm && SEQ_GT(th_ack, rsm->r_start)) {
7543 		changed = th_ack - rsm->r_start;
7544 	} else if ((rsm == NULL) && ((th_ack - 1) == tp->iss)) {
7545 		/*
7546 		 * For the SYN incoming case we will not have called
7547 		 * tcp_output for the sending of the SYN, so there will be
7548 		 * no map. All other cases should probably be a panic.
7549 		 */
7550 		if ((to->to_flags & TOF_TS) && (to->to_tsecr != 0)) {
7551 			/*
7552 			 * We have a timestamp that can be used to generate
7553 			 * an initial RTT.
7554 			 */
7555 			uint32_t ts, now, rtt;
7556 
7557 			ts = bbr_ts_convert(to->to_tsecr);
7558 			now = bbr_ts_convert(tcp_tv_to_mssectick(&bbr->rc_tv));
7559 			rtt = now - ts;
7560 			if (rtt < 1)
7561 				rtt = 1;
7562 			bbr_log_type_bbrrttprop(bbr, rtt,
7563 						tp->iss, 0, cts,
7564 						BBR_RTT_BY_TIMESTAMP, tp->iss, 0);
7565 			apply_filter_min_small(&bbr->r_ctl.rc_rttprop, rtt, cts);
7566 			changed = 1;
7567 			bbr->r_wanted_output = 1;
7568 			goto out;
7569 		}
7570 		goto proc_sack;
7571 	} else if (rsm == NULL) {
7572 		goto out;
7573 	}
7574 	if (changed) {
7575 		/*
7576 		 * The ACK point is advancing to th_ack, we must drop off
7577 		 * the packets in the rack log and calculate any eligble
7578 		 * RTT's.
7579 		 */
7580 		bbr->r_wanted_output = 1;
7581 more:
7582 		if (rsm == NULL) {
7583 
7584 			if (tp->t_flags & TF_SENTFIN) {
7585 				/* if we send a FIN we will not hav a map */
7586 				goto proc_sack;
7587 			}
7588 #ifdef BBR_INVARIANTS
7589 			panic("No rack map tp:%p for th:%p state:%d bbr:%p snd_una:%u snd_max:%u chg:%d\n",
7590 			    tp,
7591 			    th, tp->t_state, bbr,
7592 			    tp->snd_una, tp->snd_max, changed);
7593 #endif
7594 			goto proc_sack;
7595 		}
7596 	}
7597 	if (SEQ_LT(th_ack, rsm->r_start)) {
7598 		/* Huh map is missing this */
7599 #ifdef BBR_INVARIANTS
7600 		printf("Rack map starts at r_start:%u for th_ack:%u huh? ts:%d rs:%d bbr:%p\n",
7601 		    rsm->r_start,
7602 		    th_ack, tp->t_state,
7603 		    bbr->r_state, bbr);
7604 		panic("th-ack is bad bbr:%p tp:%p", bbr, tp);
7605 #endif
7606 		goto proc_sack;
7607 	} else if (th_ack == rsm->r_start) {
7608 		/* None here to ack */
7609 		goto proc_sack;
7610 	}
7611 	/*
7612 	 * Clear the dup ack counter, it will
7613 	 * either be freed or if there is some
7614 	 * remaining we need to start it at zero.
7615 	 */
7616 	rsm->r_dupack = 0;
7617 	/* Now do we consume the whole thing? */
7618 	if (SEQ_GEQ(th_ack, rsm->r_end)) {
7619 		/* Its all consumed. */
7620 		uint32_t left;
7621 
7622 		if (rsm->r_flags & BBR_ACKED) {
7623 			/*
7624 			 * It was acked on the scoreboard -- remove it from
7625 			 * total
7626 			 */
7627 			p_acked += (rsm->r_end - rsm->r_start);
7628 			bbr->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
7629 			if (bbr->r_ctl.rc_sacked == 0)
7630 				bbr->r_ctl.rc_sacklast = NULL;
7631 		} else {
7632 			bbr_update_rtt(tp, bbr, rsm, to, cts, BBR_CUM_ACKED, th_ack);
7633 			if (rsm->r_flags & BBR_MARKED_LOST) {
7634 				bbr->r_ctl.rc_lost_bytes -= rsm->r_end - rsm->r_start;
7635 			}
7636 			if (rsm->r_flags & BBR_SACK_PASSED) {
7637 				/*
7638 				 * There are acked segments ACKED on the
7639 				 * scoreboard further up. We are seeing
7640 				 * reordering.
7641 				 */
7642 				BBR_STAT_INC(bbr_reorder_seen);
7643 				bbr->r_ctl.rc_reorder_ts = cts;
7644 				if (rsm->r_flags & BBR_MARKED_LOST) {
7645 					bbr->r_ctl.rc_lost -= rsm->r_end - rsm->r_start;
7646 					if (SEQ_GT(bbr->r_ctl.rc_lt_lost, bbr->r_ctl.rc_lost))
7647 						/* LT sampling also needs adjustment */
7648 						bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
7649 				}
7650 			}
7651 			rsm->r_flags &= ~BBR_MARKED_LOST;
7652 		}
7653 		bbr->r_ctl.rc_holes_rxt -= rsm->r_rtr_bytes;
7654 		rsm->r_rtr_bytes = 0;
7655 		TAILQ_REMOVE(&bbr->r_ctl.rc_map, rsm, r_next);
7656 		if (rsm->r_in_tmap) {
7657 			TAILQ_REMOVE(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
7658 			rsm->r_in_tmap = 0;
7659 		}
7660 		if (bbr->r_ctl.rc_next == rsm) {
7661 			/* scoot along the marker */
7662 			bbr->r_ctl.rc_next = TAILQ_FIRST(&bbr->r_ctl.rc_map);
7663 		}
7664 		bbr_isit_a_pkt_epoch(bbr, cts, rsm, __LINE__, BBR_CUM_ACKED);
7665 		/* Adjust the packet counts */
7666 		left = th_ack - rsm->r_end;
7667 		/* Free back to zone */
7668 		bbr_free(bbr, rsm);
7669 		if (left) {
7670 			rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
7671 			goto more;
7672 		}
7673 		goto proc_sack;
7674 	}
7675 	if (rsm->r_flags & BBR_ACKED) {
7676 		/*
7677 		 * It was acked on the scoreboard -- remove it from total
7678 		 * for the part being cum-acked.
7679 		 */
7680 		p_acked += (rsm->r_end - rsm->r_start);
7681 		bbr->r_ctl.rc_sacked -= (th_ack - rsm->r_start);
7682 		if (bbr->r_ctl.rc_sacked == 0)
7683 			bbr->r_ctl.rc_sacklast = NULL;
7684 	} else {
7685 		/*
7686 		 * It was acked up to th_ack point for the first time
7687 		 */
7688 		struct bbr_sendmap lrsm;
7689 
7690 		memcpy(&lrsm, rsm, sizeof(struct bbr_sendmap));
7691 		lrsm.r_end = th_ack;
7692 		bbr_update_rtt(tp, bbr, &lrsm, to, cts, BBR_CUM_ACKED, th_ack);
7693 	}
7694 	if ((rsm->r_flags & BBR_MARKED_LOST) &&
7695 	    ((rsm->r_flags & BBR_ACKED) == 0)) {
7696 		/*
7697 		 * It was marked lost and partly ack'd now
7698 		 * for the first time. We lower the rc_lost_bytes
7699 		 * and still leave it MARKED.
7700 		 */
7701 		bbr->r_ctl.rc_lost_bytes -= th_ack - rsm->r_start;
7702 	}
7703 	bbr_isit_a_pkt_epoch(bbr, cts, rsm, __LINE__, BBR_CUM_ACKED);
7704 	bbr->r_ctl.rc_holes_rxt -= rsm->r_rtr_bytes;
7705 	rsm->r_rtr_bytes = 0;
7706 	/* adjust packet count */
7707 	rsm->r_start = th_ack;
7708 proc_sack:
7709 	/* Check for reneging */
7710 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
7711 	if (rsm && (rsm->r_flags & BBR_ACKED) && (th_ack == rsm->r_start)) {
7712 		/*
7713 		 * The peer has moved snd_una up to the edge of this send,
7714 		 * i.e. one that it had previously acked. The only way that
7715 		 * can be true if the peer threw away data (space issues)
7716 		 * that it had previously sacked (else it would have given
7717 		 * us snd_una up to (rsm->r_end). We need to undo the acked
7718 		 * markings here.
7719 		 *
7720 		 * Note we have to look to make sure th_ack is our
7721 		 * rsm->r_start in case we get an old ack where th_ack is
7722 		 * behind snd_una.
7723 		 */
7724 		bbr_peer_reneges(bbr, rsm, th->th_ack);
7725 	}
7726 	if ((to->to_flags & TOF_SACK) == 0) {
7727 		/* We are done nothing left to log */
7728 		goto out;
7729 	}
7730 	rsm = TAILQ_LAST_FAST(&bbr->r_ctl.rc_map, bbr_sendmap, r_next);
7731 	if (rsm) {
7732 		last_seq = rsm->r_end;
7733 	} else {
7734 		last_seq = tp->snd_max;
7735 	}
7736 	/* Sack block processing */
7737 	if (SEQ_GT(th_ack, tp->snd_una))
7738 		ack_point = th_ack;
7739 	else
7740 		ack_point = tp->snd_una;
7741 	for (i = 0; i < to->to_nsacks; i++) {
7742 		bcopy((to->to_sacks + i * TCPOLEN_SACK),
7743 		    &sack, sizeof(sack));
7744 		sack.start = ntohl(sack.start);
7745 		sack.end = ntohl(sack.end);
7746 		if (SEQ_GT(sack.end, sack.start) &&
7747 		    SEQ_GT(sack.start, ack_point) &&
7748 		    SEQ_LT(sack.start, tp->snd_max) &&
7749 		    SEQ_GT(sack.end, ack_point) &&
7750 		    SEQ_LEQ(sack.end, tp->snd_max)) {
7751 			if ((bbr->r_ctl.rc_num_small_maps_alloced > bbr_sack_block_limit) &&
7752 			    (SEQ_LT(sack.end, last_seq)) &&
7753 			    ((sack.end - sack.start) < (p_maxseg / 8))) {
7754 				/*
7755 				 * Not the last piece and its smaller than
7756 				 * 1/8th of a p_maxseg. We ignore this.
7757 				 */
7758 				BBR_STAT_INC(bbr_runt_sacks);
7759 				continue;
7760 			}
7761 			sack_blocks[num_sack_blks] = sack;
7762 			num_sack_blks++;
7763 #ifdef NETFLIX_STATS
7764 		} else if (SEQ_LEQ(sack.start, th_ack) &&
7765 		    SEQ_LEQ(sack.end, th_ack)) {
7766 			/*
7767 			 * Its a D-SACK block.
7768 			 */
7769 			tcp_record_dsack(sack.start, sack.end);
7770 #endif
7771 		}
7772 	}
7773 	if (num_sack_blks == 0)
7774 		goto out;
7775 	/*
7776 	 * Sort the SACK blocks so we can update the rack scoreboard with
7777 	 * just one pass.
7778 	 */
7779 	new_sb = sack_filter_blks(&bbr->r_ctl.bbr_sf, sack_blocks,
7780 				  num_sack_blks, th->th_ack);
7781 	ctf_log_sack_filter(bbr->rc_tp, new_sb, sack_blocks);
7782 	BBR_STAT_ADD(bbr_sack_blocks, num_sack_blks);
7783 	BBR_STAT_ADD(bbr_sack_blocks_skip, (num_sack_blks - new_sb));
7784 	num_sack_blks = new_sb;
7785 	if (num_sack_blks < 2) {
7786 		goto do_sack_work;
7787 	}
7788 	/* Sort the sacks */
7789 	for (i = 0; i < num_sack_blks; i++) {
7790 		for (j = i + 1; j < num_sack_blks; j++) {
7791 			if (SEQ_GT(sack_blocks[i].end, sack_blocks[j].end)) {
7792 				sack = sack_blocks[i];
7793 				sack_blocks[i] = sack_blocks[j];
7794 				sack_blocks[j] = sack;
7795 			}
7796 		}
7797 	}
7798 	/*
7799 	 * Now are any of the sack block ends the same (yes some
7800 	 * implememtations send these)?
7801 	 */
7802 again:
7803 	if (num_sack_blks > 1) {
7804 		for (i = 0; i < num_sack_blks; i++) {
7805 			for (j = i + 1; j < num_sack_blks; j++) {
7806 				if (sack_blocks[i].end == sack_blocks[j].end) {
7807 					/*
7808 					 * Ok these two have the same end we
7809 					 * want the smallest end and then
7810 					 * throw away the larger and start
7811 					 * again.
7812 					 */
7813 					if (SEQ_LT(sack_blocks[j].start, sack_blocks[i].start)) {
7814 						/*
7815 						 * The second block covers
7816 						 * more area use that
7817 						 */
7818 						sack_blocks[i].start = sack_blocks[j].start;
7819 					}
7820 					/*
7821 					 * Now collapse out the dup-sack and
7822 					 * lower the count
7823 					 */
7824 					for (k = (j + 1); k < num_sack_blks; k++) {
7825 						sack_blocks[j].start = sack_blocks[k].start;
7826 						sack_blocks[j].end = sack_blocks[k].end;
7827 						j++;
7828 					}
7829 					num_sack_blks--;
7830 					goto again;
7831 				}
7832 			}
7833 		}
7834 	}
7835 do_sack_work:
7836 	rsm = bbr->r_ctl.rc_sacklast;
7837 	for (i = 0; i < num_sack_blks; i++) {
7838 		acked = bbr_proc_sack_blk(tp, bbr, &sack_blocks[i], to, &rsm, cts);
7839 		if (acked) {
7840 			bbr->r_wanted_output = 1;
7841 			changed += acked;
7842 			sack_changed += acked;
7843 		}
7844 	}
7845 out:
7846 	*prev_acked = p_acked;
7847 	if ((sack_changed) && (!IN_RECOVERY(tp->t_flags))) {
7848 		/*
7849 		 * Ok we have a high probability that we need to go in to
7850 		 * recovery since we have data sack'd
7851 		 */
7852 		struct bbr_sendmap *rsm;
7853 
7854 		rsm = bbr_check_recovery_mode(tp, bbr, cts);
7855 		if (rsm) {
7856 			/* Enter recovery */
7857 			entered_recovery = 1;
7858 			bbr->r_wanted_output = 1;
7859 			/*
7860 			 * When we enter recovery we need to assure we send
7861 			 * one packet.
7862 			 */
7863 			if (bbr->r_ctl.rc_resend == NULL) {
7864 				bbr->r_ctl.rc_resend = rsm;
7865 			}
7866 		}
7867 	}
7868 	if (IN_RECOVERY(tp->t_flags) && (entered_recovery == 0)) {
7869 		/*
7870 		 * See if we need to rack-retransmit anything if so set it
7871 		 * up as the thing to resend assuming something else is not
7872 		 * already in that position.
7873 		 */
7874 		if (bbr->r_ctl.rc_resend == NULL) {
7875 			bbr->r_ctl.rc_resend = bbr_check_recovery_mode(tp, bbr, cts);
7876 		}
7877 	}
7878 	/*
7879 	 * We return the amount that changed via sack, this is used by the
7880 	 * ack-received code to augment what was changed between th_ack <->
7881 	 * snd_una.
7882 	 */
7883 	return (sack_changed);
7884 }
7885 
7886 static void
7887 bbr_strike_dupack(struct tcp_bbr *bbr)
7888 {
7889 	struct bbr_sendmap *rsm;
7890 
7891 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_tmap);
7892 	if (rsm && (rsm->r_dupack < 0xff)) {
7893 		rsm->r_dupack++;
7894 		if (rsm->r_dupack >= DUP_ACK_THRESHOLD)
7895 			bbr->r_wanted_output = 1;
7896 	}
7897 }
7898 
7899 /*
7900  * Return value of 1, we do not need to call bbr_process_data().
7901  * return value of 0, bbr_process_data can be called.
7902  * For ret_val if its 0 the TCB is locked and valid, if its non-zero
7903  * its unlocked and probably unsafe to touch the TCB.
7904  */
7905 static int
7906 bbr_process_ack(struct mbuf *m, struct tcphdr *th, struct socket *so,
7907     struct tcpcb *tp, struct tcpopt *to,
7908     uint32_t tiwin, int32_t tlen,
7909     int32_t * ofia, int32_t thflags, int32_t * ret_val)
7910 {
7911 	int32_t ourfinisacked = 0;
7912 	int32_t acked_amount;
7913 	uint16_t nsegs;
7914 	int32_t acked;
7915 	uint32_t lost, sack_changed = 0;
7916 	struct mbuf *mfree;
7917 	struct tcp_bbr *bbr;
7918 	uint32_t prev_acked = 0;
7919 
7920 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
7921 	lost = bbr->r_ctl.rc_lost;
7922 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
7923 	if (SEQ_GT(th->th_ack, tp->snd_max)) {
7924 		ctf_do_dropafterack(m, tp, th, thflags, tlen, ret_val);
7925 		bbr->r_wanted_output = 1;
7926 		return (1);
7927 	}
7928 	if (SEQ_GEQ(th->th_ack, tp->snd_una) || to->to_nsacks) {
7929 		/* Process the ack */
7930 		if (bbr->rc_in_persist)
7931 			tp->t_rxtshift = 0;
7932 		if ((th->th_ack == tp->snd_una) && (tiwin == tp->snd_wnd))
7933 		        bbr_strike_dupack(bbr);
7934 		sack_changed = bbr_log_ack(tp, to, th, &prev_acked);
7935 	}
7936 	bbr_lt_bw_sampling(bbr, bbr->r_ctl.rc_rcvtime, (bbr->r_ctl.rc_lost > lost));
7937 	if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
7938 		/*
7939 		 * Old ack, behind the last one rcv'd or a duplicate ack
7940 		 * with SACK info.
7941 		 */
7942 		if (th->th_ack == tp->snd_una) {
7943 			bbr_ack_received(tp, bbr, th, 0, sack_changed, prev_acked, __LINE__, 0);
7944 			if (bbr->r_state == TCPS_SYN_SENT) {
7945 				/*
7946 				 * Special case on where we sent SYN. When
7947 				 * the SYN-ACK is processed in syn_sent
7948 				 * state it bumps the snd_una. This causes
7949 				 * us to hit here even though we did ack 1
7950 				 * byte.
7951 				 *
7952 				 * Go through the nothing left case so we
7953 				 * send data.
7954 				 */
7955 				goto nothing_left;
7956 			}
7957 		}
7958 		return (0);
7959 	}
7960 	/*
7961 	 * If we reach this point, ACK is not a duplicate, i.e., it ACKs
7962 	 * something we sent.
7963 	 */
7964 	if (tp->t_flags & TF_NEEDSYN) {
7965 		/*
7966 		 * T/TCP: Connection was half-synchronized, and our SYN has
7967 		 * been ACK'd (so connection is now fully synchronized).  Go
7968 		 * to non-starred state, increment snd_una for ACK of SYN,
7969 		 * and check if we can do window scaling.
7970 		 */
7971 		tp->t_flags &= ~TF_NEEDSYN;
7972 		tp->snd_una++;
7973 		/* Do window scaling? */
7974 		if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
7975 		    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
7976 			tp->rcv_scale = tp->request_r_scale;
7977 			/* Send window already scaled. */
7978 		}
7979 	}
7980 	INP_WLOCK_ASSERT(tp->t_inpcb);
7981 
7982 	acked = BYTES_THIS_ACK(tp, th);
7983 	KMOD_TCPSTAT_ADD(tcps_rcvackpack, (int)nsegs);
7984 	KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
7985 
7986 	/*
7987 	 * If we just performed our first retransmit, and the ACK arrives
7988 	 * within our recovery window, then it was a mistake to do the
7989 	 * retransmit in the first place.  Recover our original cwnd and
7990 	 * ssthresh, and proceed to transmit where we left off.
7991 	 */
7992 	if (tp->t_flags & TF_PREVVALID) {
7993 		tp->t_flags &= ~TF_PREVVALID;
7994 		if (tp->t_rxtshift == 1 &&
7995 		    (int)(ticks - tp->t_badrxtwin) < 0)
7996 			bbr_cong_signal(tp, th, CC_RTO_ERR, NULL);
7997 	}
7998 	SOCKBUF_LOCK(&so->so_snd);
7999 	acked_amount = min(acked, (int)sbavail(&so->so_snd));
8000 	tp->snd_wnd -= acked_amount;
8001 	mfree = sbcut_locked(&so->so_snd, acked_amount);
8002 	/* NB: sowwakeup_locked() does an implicit unlock. */
8003 	sowwakeup_locked(so);
8004 	m_freem(mfree);
8005 	if (SEQ_GT(th->th_ack, tp->snd_una)) {
8006 		bbr_collapse_rtt(tp, bbr, TCP_REXMTVAL(tp));
8007 	}
8008 	tp->snd_una = th->th_ack;
8009 	bbr_ack_received(tp, bbr, th, acked, sack_changed, prev_acked, __LINE__, (bbr->r_ctl.rc_lost - lost));
8010 	if (IN_RECOVERY(tp->t_flags)) {
8011 		if (SEQ_LT(th->th_ack, tp->snd_recover) &&
8012 		    (SEQ_LT(th->th_ack, tp->snd_max))) {
8013 			tcp_bbr_partialack(tp);
8014 		} else {
8015 			bbr_post_recovery(tp);
8016 		}
8017 	}
8018 	if (SEQ_GT(tp->snd_una, tp->snd_recover)) {
8019 		tp->snd_recover = tp->snd_una;
8020 	}
8021 	if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
8022 		tp->snd_nxt = tp->snd_max;
8023 	}
8024 	if (tp->snd_una == tp->snd_max) {
8025 		/* Nothing left outstanding */
8026 nothing_left:
8027 		bbr_log_progress_event(bbr, tp, ticks, PROGRESS_CLEAR, __LINE__);
8028 		if (sbavail(&tp->t_inpcb->inp_socket->so_snd) == 0)
8029 			bbr->rc_tp->t_acktime = 0;
8030 		if ((sbused(&so->so_snd) == 0) &&
8031 		    (tp->t_flags & TF_SENTFIN)) {
8032 			ourfinisacked = 1;
8033 		}
8034 		bbr_timer_cancel(bbr, __LINE__, bbr->r_ctl.rc_rcvtime);
8035 		if (bbr->rc_in_persist == 0) {
8036 			bbr->r_ctl.rc_went_idle_time = bbr->r_ctl.rc_rcvtime;
8037 		}
8038 		sack_filter_clear(&bbr->r_ctl.bbr_sf, tp->snd_una);
8039 		bbr_log_ack_clear(bbr, bbr->r_ctl.rc_rcvtime);
8040 		/*
8041 		 * We invalidate the last ack here since we
8042 		 * don't want to transfer forward the time
8043 		 * for our sum's calculations.
8044 		 */
8045 		if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
8046 		    (sbavail(&so->so_snd) == 0) &&
8047 		    (tp->t_flags2 & TF2_DROP_AF_DATA)) {
8048 			/*
8049 			 * The socket was gone and the peer sent data, time
8050 			 * to reset him.
8051 			 */
8052 			*ret_val = 1;
8053 			tp = tcp_close(tp);
8054 			ctf_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, tlen);
8055 			BBR_STAT_INC(bbr_dropped_af_data);
8056 			return (1);
8057 		}
8058 		/* Set need output so persist might get set */
8059 		bbr->r_wanted_output = 1;
8060 	}
8061 	if (ofia)
8062 		*ofia = ourfinisacked;
8063 	return (0);
8064 }
8065 
8066 static void
8067 bbr_enter_persist(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts, int32_t line)
8068 {
8069 	if (bbr->rc_in_persist == 0) {
8070 		bbr_timer_cancel(bbr, __LINE__, cts);
8071 		bbr->r_ctl.rc_last_delay_val = 0;
8072 		tp->t_rxtshift = 0;
8073 		bbr->rc_in_persist = 1;
8074 		bbr->r_ctl.rc_went_idle_time = cts;
8075 		/* We should be capped when rw went to 0 but just in case */
8076 		bbr_log_type_pesist(bbr, cts, 0, line, 1);
8077 		/* Time freezes for the state, so do the accounting now */
8078 		if (SEQ_GT(cts, bbr->r_ctl.rc_bbr_state_time)) {
8079 			uint32_t time_in;
8080 
8081 			time_in = cts - bbr->r_ctl.rc_bbr_state_time;
8082 			if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW) {
8083 				int32_t idx;
8084 
8085 				idx = bbr_state_val(bbr);
8086 				counter_u64_add(bbr_state_time[(idx + 5)], time_in);
8087 			} else {
8088 				counter_u64_add(bbr_state_time[bbr->rc_bbr_state], time_in);
8089 			}
8090 		}
8091 		bbr->r_ctl.rc_bbr_state_time = cts;
8092 	}
8093 }
8094 
8095 static void
8096 bbr_restart_after_idle(struct tcp_bbr *bbr, uint32_t cts, uint32_t idle_time)
8097 {
8098 	/*
8099 	 * Note that if idle time does not exceed our
8100 	 * threshold, we do nothing continuing the state
8101 	 * transitions we were last walking through.
8102 	 */
8103 	if (idle_time >= bbr_idle_restart_threshold) {
8104 		if (bbr->rc_use_idle_restart) {
8105 			bbr->rc_bbr_state = BBR_STATE_IDLE_EXIT;
8106 			/*
8107 			 * Set our target using BBR_UNIT, so
8108 			 * we increase at a dramatic rate but
8109 			 * we stop when we get the pipe
8110 			 * full again for our current b/w estimate.
8111 			 */
8112 			bbr->r_ctl.rc_bbr_hptsi_gain = BBR_UNIT;
8113 			bbr->r_ctl.rc_bbr_cwnd_gain = BBR_UNIT;
8114 			bbr_set_state_target(bbr, __LINE__);
8115 			/* Now setup our gains to ramp up */
8116 			bbr->r_ctl.rc_bbr_hptsi_gain = bbr->r_ctl.rc_startup_pg;
8117 			bbr->r_ctl.rc_bbr_cwnd_gain = bbr->r_ctl.rc_startup_pg;
8118 			bbr_log_type_statechange(bbr, cts, __LINE__);
8119 		} else {
8120 			bbr_substate_change(bbr, cts, __LINE__, 1);
8121 		}
8122 	}
8123 }
8124 
8125 static void
8126 bbr_exit_persist(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts, int32_t line)
8127 {
8128 	uint32_t idle_time;
8129 
8130 	if (bbr->rc_in_persist == 0)
8131 		return;
8132 	idle_time = bbr_calc_time(cts, bbr->r_ctl.rc_went_idle_time);
8133 	bbr->rc_in_persist = 0;
8134 	bbr->rc_hit_state_1 = 0;
8135 	tp->t_flags &= ~TF_FORCEDATA;
8136 	bbr->r_ctl.rc_del_time = cts;
8137 	/*
8138 	 * We invalidate the last ack here since we
8139 	 * don't want to transfer forward the time
8140 	 * for our sum's calculations.
8141 	 */
8142 	if (bbr->rc_inp->inp_in_hpts) {
8143 		tcp_hpts_remove(bbr->rc_inp, HPTS_REMOVE_OUTPUT);
8144 		bbr->rc_timer_first = 0;
8145 		bbr->r_ctl.rc_hpts_flags = 0;
8146 		bbr->r_ctl.rc_last_delay_val = 0;
8147 		bbr->r_ctl.rc_hptsi_agg_delay = 0;
8148 		bbr->r_agg_early_set = 0;
8149 		bbr->r_ctl.rc_agg_early = 0;
8150 	}
8151 	bbr_log_type_pesist(bbr, cts, idle_time, line, 0);
8152 	if (idle_time >= bbr_rtt_probe_time) {
8153 		/*
8154 		 * This qualifies as a RTT_PROBE session since we drop the
8155 		 * data outstanding to nothing and waited more than
8156 		 * bbr_rtt_probe_time.
8157 		 */
8158 		bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_PERSIST, 0);
8159 		bbr->r_ctl.last_in_probertt = bbr->r_ctl.rc_rtt_shrinks = cts;
8160 	}
8161 	tp->t_rxtshift = 0;
8162 	/*
8163 	 * If in probeBW and we have persisted more than an RTT lets do
8164 	 * special handling.
8165 	 */
8166 	/* Force a time based epoch */
8167 	bbr_set_epoch(bbr, cts, __LINE__);
8168 	/*
8169 	 * Setup the lost so we don't count anything against the guy
8170 	 * we have been stuck with during persists.
8171 	 */
8172 	bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
8173 	/* Time un-freezes for the state */
8174 	bbr->r_ctl.rc_bbr_state_time = cts;
8175 	if ((bbr->rc_bbr_state == BBR_STATE_PROBE_BW) ||
8176 	    (bbr->rc_bbr_state == BBR_STATE_PROBE_RTT)) {
8177 		/*
8178 		 * If we are going back to probe-bw
8179 		 * or probe_rtt, we may need to possibly
8180 		 * do a fast restart.
8181 		 */
8182 		bbr_restart_after_idle(bbr, cts, idle_time);
8183 	}
8184 }
8185 
8186 static void
8187 bbr_collapsed_window(struct tcp_bbr *bbr)
8188 {
8189 	/*
8190 	 * Now we must walk the
8191 	 * send map and divide the
8192 	 * ones left stranded. These
8193 	 * guys can't cause us to abort
8194 	 * the connection and are really
8195 	 * "unsent". However if a buggy
8196 	 * client actually did keep some
8197 	 * of the data i.e. collapsed the win
8198 	 * and refused to ack and then opened
8199 	 * the win and acked that data. We would
8200 	 * get into an ack war, the simplier
8201 	 * method then of just pretending we
8202 	 * did not send those segments something
8203 	 * won't work.
8204 	 */
8205 	struct bbr_sendmap *rsm, *nrsm;
8206 	tcp_seq max_seq;
8207 	uint32_t maxseg;
8208 	int can_split = 0;
8209 	int fnd = 0;
8210 
8211 	maxseg = bbr->rc_tp->t_maxseg - bbr->rc_last_options;
8212 	max_seq = bbr->rc_tp->snd_una + bbr->rc_tp->snd_wnd;
8213 	bbr_log_type_rwnd_collapse(bbr, max_seq, 1, 0);
8214 	TAILQ_FOREACH(rsm, &bbr->r_ctl.rc_map, r_next) {
8215 		/* Find the first seq past or at maxseq */
8216 		if (rsm->r_flags & BBR_RWND_COLLAPSED)
8217 			rsm->r_flags &= ~BBR_RWND_COLLAPSED;
8218 		if (SEQ_GEQ(max_seq, rsm->r_start) &&
8219 		    SEQ_GEQ(rsm->r_end, max_seq)) {
8220 			fnd = 1;
8221 			break;
8222 		}
8223 	}
8224 	bbr->rc_has_collapsed = 0;
8225 	if (!fnd) {
8226 		/* Nothing to do strange */
8227 		return;
8228 	}
8229 	/*
8230 	 * Now can we split?
8231 	 *
8232 	 * We don't want to split if splitting
8233 	 * would generate too many small segments
8234 	 * less we let an attacker fragment our
8235 	 * send_map and leave us out of memory.
8236 	 */
8237 	if ((max_seq != rsm->r_start) &&
8238 	    (max_seq != rsm->r_end)){
8239 		/* can we split? */
8240 		int res1, res2;
8241 
8242 		res1 = max_seq - rsm->r_start;
8243 		res2 = rsm->r_end - max_seq;
8244 		if ((res1 >= (maxseg/8)) &&
8245 		    (res2 >= (maxseg/8))) {
8246 			/* No small pieces here */
8247 			can_split = 1;
8248 		} else if (bbr->r_ctl.rc_num_small_maps_alloced < bbr_sack_block_limit) {
8249 			/* We are under the limit */
8250 			can_split = 1;
8251 		}
8252 	}
8253 	/* Ok do we need to split this rsm? */
8254 	if (max_seq == rsm->r_start) {
8255 		/* It's this guy no split required */
8256 		nrsm = rsm;
8257 	} else if (max_seq == rsm->r_end) {
8258 		/* It's the next one no split required. */
8259 		nrsm = TAILQ_NEXT(rsm, r_next);
8260 		if (nrsm == NULL) {
8261 			/* Huh? */
8262 			return;
8263 		}
8264 	} else if (can_split && SEQ_LT(max_seq, rsm->r_end)) {
8265 		/* yep we need to split it */
8266 		nrsm = bbr_alloc_limit(bbr, BBR_LIMIT_TYPE_SPLIT);
8267 		if (nrsm == NULL) {
8268 			/* failed XXXrrs what can we do mark the whole? */
8269 			nrsm = rsm;
8270 			goto no_split;
8271 		}
8272 		/* Clone it */
8273 		bbr_log_type_rwnd_collapse(bbr, max_seq, 3, 0);
8274 		bbr_clone_rsm(bbr, nrsm, rsm, max_seq);
8275 		TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_map, rsm, nrsm, r_next);
8276 		if (rsm->r_in_tmap) {
8277 			TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
8278 			nrsm->r_in_tmap = 1;
8279 		}
8280 	} else {
8281 		/*
8282 		 * Split not allowed just start here just
8283 		 * use this guy.
8284 		 */
8285 		nrsm = rsm;
8286 	}
8287 no_split:
8288 	BBR_STAT_INC(bbr_collapsed_win);
8289 	/* reuse fnd as a count */
8290 	fnd = 0;
8291 	TAILQ_FOREACH_FROM(nrsm, &bbr->r_ctl.rc_map, r_next) {
8292 		nrsm->r_flags |= BBR_RWND_COLLAPSED;
8293 		fnd++;
8294 		bbr->rc_has_collapsed = 1;
8295 	}
8296 	bbr_log_type_rwnd_collapse(bbr, max_seq, 4, fnd);
8297 }
8298 
8299 static void
8300 bbr_un_collapse_window(struct tcp_bbr *bbr)
8301 {
8302 	struct bbr_sendmap *rsm;
8303 	int cleared = 0;
8304 
8305 	TAILQ_FOREACH_REVERSE(rsm, &bbr->r_ctl.rc_map, bbr_head, r_next) {
8306 		if (rsm->r_flags & BBR_RWND_COLLAPSED) {
8307 			/* Clear the flag */
8308 			rsm->r_flags &= ~BBR_RWND_COLLAPSED;
8309 			cleared++;
8310 		} else
8311 			break;
8312 	}
8313 	bbr_log_type_rwnd_collapse(bbr,
8314 				   (bbr->rc_tp->snd_una + bbr->rc_tp->snd_wnd), 0, cleared);
8315 	bbr->rc_has_collapsed = 0;
8316 }
8317 
8318 /*
8319  * Return value of 1, the TCB is unlocked and most
8320  * likely gone, return value of 0, the TCB is still
8321  * locked.
8322  */
8323 static int
8324 bbr_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so,
8325     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
8326     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
8327 {
8328 	/*
8329 	 * Update window information. Don't look at window if no ACK: TAC's
8330 	 * send garbage on first SYN.
8331 	 */
8332 	uint16_t nsegs;
8333 	int32_t tfo_syn;
8334 	struct tcp_bbr *bbr;
8335 
8336 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
8337 	INP_WLOCK_ASSERT(tp->t_inpcb);
8338 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
8339 	if ((thflags & TH_ACK) &&
8340 	    (SEQ_LT(tp->snd_wl1, th->th_seq) ||
8341 	    (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) ||
8342 	    (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) {
8343 		/* keep track of pure window updates */
8344 		if (tlen == 0 &&
8345 		    tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd)
8346 			KMOD_TCPSTAT_INC(tcps_rcvwinupd);
8347 		tp->snd_wnd = tiwin;
8348 		tp->snd_wl1 = th->th_seq;
8349 		tp->snd_wl2 = th->th_ack;
8350 		if (tp->snd_wnd > tp->max_sndwnd)
8351 			tp->max_sndwnd = tp->snd_wnd;
8352 		bbr->r_wanted_output = 1;
8353 	} else if (thflags & TH_ACK) {
8354 		if ((tp->snd_wl2 == th->th_ack) && (tiwin < tp->snd_wnd)) {
8355 			tp->snd_wnd = tiwin;
8356 			tp->snd_wl1 = th->th_seq;
8357 			tp->snd_wl2 = th->th_ack;
8358 		}
8359 	}
8360 	if (tp->snd_wnd < ctf_outstanding(tp))
8361 		/* The peer collapsed its window on us */
8362 		bbr_collapsed_window(bbr);
8363  	else if (bbr->rc_has_collapsed)
8364 		bbr_un_collapse_window(bbr);
8365 	/* Was persist timer active and now we have window space? */
8366 	if ((bbr->rc_in_persist != 0) &&
8367 	    (tp->snd_wnd >= min((bbr->r_ctl.rc_high_rwnd/2),
8368 				bbr_minseg(bbr)))) {
8369 		/*
8370 		 * Make the rate persist at end of persist mode if idle long
8371 		 * enough
8372 		 */
8373 		bbr_exit_persist(tp, bbr, bbr->r_ctl.rc_rcvtime, __LINE__);
8374 
8375 		/* Make sure we output to start the timer */
8376 		bbr->r_wanted_output = 1;
8377 	}
8378 	/* Do we need to enter persist? */
8379 	if ((bbr->rc_in_persist == 0) &&
8380 	    (tp->snd_wnd < min((bbr->r_ctl.rc_high_rwnd/2), bbr_minseg(bbr))) &&
8381 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
8382 	    (tp->snd_max == tp->snd_una) &&
8383 	    sbavail(&tp->t_inpcb->inp_socket->so_snd) &&
8384 	    (sbavail(&tp->t_inpcb->inp_socket->so_snd) > tp->snd_wnd)) {
8385 		/* No send window.. we must enter persist */
8386 		bbr_enter_persist(tp, bbr, bbr->r_ctl.rc_rcvtime, __LINE__);
8387 	}
8388 	if (tp->t_flags2 & TF2_DROP_AF_DATA) {
8389 		m_freem(m);
8390 		return (0);
8391 	}
8392 	/*
8393 	 * Process segments with URG.
8394 	 */
8395 	if ((thflags & TH_URG) && th->th_urp &&
8396 	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
8397 		/*
8398 		 * This is a kludge, but if we receive and accept random
8399 		 * urgent pointers, we'll crash in soreceive.  It's hard to
8400 		 * imagine someone actually wanting to send this much urgent
8401 		 * data.
8402 		 */
8403 		SOCKBUF_LOCK(&so->so_rcv);
8404 		if (th->th_urp + sbavail(&so->so_rcv) > sb_max) {
8405 			th->th_urp = 0;	/* XXX */
8406 			thflags &= ~TH_URG;	/* XXX */
8407 			SOCKBUF_UNLOCK(&so->so_rcv);	/* XXX */
8408 			goto dodata;	/* XXX */
8409 		}
8410 		/*
8411 		 * If this segment advances the known urgent pointer, then
8412 		 * mark the data stream.  This should not happen in
8413 		 * CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since a
8414 		 * FIN has been received from the remote side. In these
8415 		 * states we ignore the URG.
8416 		 *
8417 		 * According to RFC961 (Assigned Protocols), the urgent
8418 		 * pointer points to the last octet of urgent data.  We
8419 		 * continue, however, to consider it to indicate the first
8420 		 * octet of data past the urgent section as the original
8421 		 * spec states (in one of two places).
8422 		 */
8423 		if (SEQ_GT(th->th_seq + th->th_urp, tp->rcv_up)) {
8424 			tp->rcv_up = th->th_seq + th->th_urp;
8425 			so->so_oobmark = sbavail(&so->so_rcv) +
8426 			    (tp->rcv_up - tp->rcv_nxt) - 1;
8427 			if (so->so_oobmark == 0)
8428 				so->so_rcv.sb_state |= SBS_RCVATMARK;
8429 			sohasoutofband(so);
8430 			tp->t_oobflags &= ~(TCPOOB_HAVEDATA | TCPOOB_HADDATA);
8431 		}
8432 		SOCKBUF_UNLOCK(&so->so_rcv);
8433 		/*
8434 		 * Remove out of band data so doesn't get presented to user.
8435 		 * This can happen independent of advancing the URG pointer,
8436 		 * but if two URG's are pending at once, some out-of-band
8437 		 * data may creep in... ick.
8438 		 */
8439 		if (th->th_urp <= (uint32_t)tlen &&
8440 		    !(so->so_options & SO_OOBINLINE)) {
8441 			/* hdr drop is delayed */
8442 			tcp_pulloutofband(so, th, m, drop_hdrlen);
8443 		}
8444 	} else {
8445 		/*
8446 		 * If no out of band data is expected, pull receive urgent
8447 		 * pointer along with the receive window.
8448 		 */
8449 		if (SEQ_GT(tp->rcv_nxt, tp->rcv_up))
8450 			tp->rcv_up = tp->rcv_nxt;
8451 	}
8452 dodata:				/* XXX */
8453 	INP_WLOCK_ASSERT(tp->t_inpcb);
8454 
8455 	/*
8456 	 * Process the segment text, merging it into the TCP sequencing
8457 	 * queue, and arranging for acknowledgment of receipt if necessary.
8458 	 * This process logically involves adjusting tp->rcv_wnd as data is
8459 	 * presented to the user (this happens in tcp_usrreq.c, case
8460 	 * PRU_RCVD).  If a FIN has already been received on this connection
8461 	 * then we just ignore the text.
8462 	 */
8463 	tfo_syn = ((tp->t_state == TCPS_SYN_RECEIVED) &&
8464 		   IS_FASTOPEN(tp->t_flags));
8465 	if ((tlen || (thflags & TH_FIN) || tfo_syn) &&
8466 	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
8467 		tcp_seq save_start = th->th_seq;
8468 		tcp_seq save_rnxt  = tp->rcv_nxt;
8469 		int     save_tlen  = tlen;
8470 
8471 		m_adj(m, drop_hdrlen);	/* delayed header drop */
8472 		/*
8473 		 * Insert segment which includes th into TCP reassembly
8474 		 * queue with control block tp.  Set thflags to whether
8475 		 * reassembly now includes a segment with FIN.  This handles
8476 		 * the common case inline (segment is the next to be
8477 		 * received on an established connection, and the queue is
8478 		 * empty), avoiding linkage into and removal from the queue
8479 		 * and repetition of various conversions. Set DELACK for
8480 		 * segments received in order, but ack immediately when
8481 		 * segments are out of order (so fast retransmit can work).
8482 		 */
8483 		if (th->th_seq == tp->rcv_nxt &&
8484 		    SEGQ_EMPTY(tp) &&
8485 		    (TCPS_HAVEESTABLISHED(tp->t_state) ||
8486 		    tfo_syn)) {
8487 #ifdef NETFLIX_SB_LIMITS
8488 			u_int mcnt, appended;
8489 
8490 			if (so->so_rcv.sb_shlim) {
8491 				mcnt = m_memcnt(m);
8492 				appended = 0;
8493 				if (counter_fo_get(so->so_rcv.sb_shlim, mcnt,
8494 				    CFO_NOSLEEP, NULL) == false) {
8495 					counter_u64_add(tcp_sb_shlim_fails, 1);
8496 					m_freem(m);
8497 					return (0);
8498 				}
8499 			}
8500 
8501 #endif
8502 			if (DELAY_ACK(tp, bbr, nsegs) || tfo_syn) {
8503 				bbr->bbr_segs_rcvd += max(1, nsegs);
8504 				tp->t_flags |= TF_DELACK;
8505 				bbr_timer_cancel(bbr, __LINE__, bbr->r_ctl.rc_rcvtime);
8506 			} else {
8507 				bbr->r_wanted_output = 1;
8508 				tp->t_flags |= TF_ACKNOW;
8509 			}
8510 			tp->rcv_nxt += tlen;
8511 			thflags = th->th_flags & TH_FIN;
8512 			KMOD_TCPSTAT_ADD(tcps_rcvpack, (int)nsegs);
8513 			KMOD_TCPSTAT_ADD(tcps_rcvbyte, tlen);
8514 			SOCKBUF_LOCK(&so->so_rcv);
8515 			if (so->so_rcv.sb_state & SBS_CANTRCVMORE)
8516 				m_freem(m);
8517 			else
8518 #ifdef NETFLIX_SB_LIMITS
8519 				appended =
8520 #endif
8521 					sbappendstream_locked(&so->so_rcv, m, 0);
8522 			/* NB: sorwakeup_locked() does an implicit unlock. */
8523 			sorwakeup_locked(so);
8524 #ifdef NETFLIX_SB_LIMITS
8525 			if (so->so_rcv.sb_shlim && appended != mcnt)
8526 				counter_fo_release(so->so_rcv.sb_shlim,
8527 				    mcnt - appended);
8528 #endif
8529 		} else {
8530 			/*
8531 			 * XXX: Due to the header drop above "th" is
8532 			 * theoretically invalid by now.  Fortunately
8533 			 * m_adj() doesn't actually frees any mbufs when
8534 			 * trimming from the head.
8535 			 */
8536 			tcp_seq temp = save_start;
8537 			thflags = tcp_reass(tp, th, &temp, &tlen, m);
8538 			tp->t_flags |= TF_ACKNOW;
8539 		}
8540 		if ((tp->t_flags & TF_SACK_PERMIT) && (save_tlen > 0)) {
8541 			if ((tlen == 0) && (SEQ_LT(save_start, save_rnxt))) {
8542 				/*
8543 				 * DSACK actually handled in the fastpath
8544 				 * above.
8545 				 */
8546 				tcp_update_sack_list(tp, save_start,
8547 				    save_start + save_tlen);
8548 			} else if ((tlen > 0) && SEQ_GT(tp->rcv_nxt, save_rnxt)) {
8549 				if ((tp->rcv_numsacks >= 1) &&
8550 				    (tp->sackblks[0].end == save_start)) {
8551 					/*
8552 					 * Partial overlap, recorded at todrop
8553 					 * above.
8554 					 */
8555 					tcp_update_sack_list(tp,
8556 					    tp->sackblks[0].start,
8557 					    tp->sackblks[0].end);
8558 				} else {
8559 					tcp_update_dsack_list(tp, save_start,
8560 					    save_start + save_tlen);
8561 				}
8562 			} else if (tlen >= save_tlen) {
8563 				/* Update of sackblks. */
8564 				tcp_update_dsack_list(tp, save_start,
8565 				    save_start + save_tlen);
8566 			} else if (tlen > 0) {
8567 				tcp_update_dsack_list(tp, save_start,
8568 				    save_start + tlen);
8569 			}
8570 		}
8571 	} else {
8572 		m_freem(m);
8573 		thflags &= ~TH_FIN;
8574 	}
8575 
8576 	/*
8577 	 * If FIN is received ACK the FIN and let the user know that the
8578 	 * connection is closing.
8579 	 */
8580 	if (thflags & TH_FIN) {
8581 		if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
8582 			socantrcvmore(so);
8583 			/*
8584 			 * If connection is half-synchronized (ie NEEDSYN
8585 			 * flag on) then delay ACK, so it may be piggybacked
8586 			 * when SYN is sent. Otherwise, since we received a
8587 			 * FIN then no more input can be expected, send ACK
8588 			 * now.
8589 			 */
8590 			if (tp->t_flags & TF_NEEDSYN) {
8591 				tp->t_flags |= TF_DELACK;
8592 				bbr_timer_cancel(bbr,
8593 				    __LINE__, bbr->r_ctl.rc_rcvtime);
8594 			} else {
8595 				tp->t_flags |= TF_ACKNOW;
8596 			}
8597 			tp->rcv_nxt++;
8598 		}
8599 		switch (tp->t_state) {
8600 
8601 			/*
8602 			 * In SYN_RECEIVED and ESTABLISHED STATES enter the
8603 			 * CLOSE_WAIT state.
8604 			 */
8605 		case TCPS_SYN_RECEIVED:
8606 			tp->t_starttime = ticks;
8607 			/* FALLTHROUGH */
8608 		case TCPS_ESTABLISHED:
8609 			tcp_state_change(tp, TCPS_CLOSE_WAIT);
8610 			break;
8611 
8612 			/*
8613 			 * If still in FIN_WAIT_1 STATE FIN has not been
8614 			 * acked so enter the CLOSING state.
8615 			 */
8616 		case TCPS_FIN_WAIT_1:
8617 			tcp_state_change(tp, TCPS_CLOSING);
8618 			break;
8619 
8620 			/*
8621 			 * In FIN_WAIT_2 state enter the TIME_WAIT state,
8622 			 * starting the time-wait timer, turning off the
8623 			 * other standard timers.
8624 			 */
8625 		case TCPS_FIN_WAIT_2:
8626 			bbr->rc_timer_first = 1;
8627 			bbr_timer_cancel(bbr,
8628 			    __LINE__, bbr->r_ctl.rc_rcvtime);
8629 			INP_WLOCK_ASSERT(tp->t_inpcb);
8630 			tcp_twstart(tp);
8631 			return (1);
8632 		}
8633 	}
8634 	/*
8635 	 * Return any desired output.
8636 	 */
8637 	if ((tp->t_flags & TF_ACKNOW) ||
8638 	    (sbavail(&so->so_snd) > ctf_outstanding(tp))) {
8639 		bbr->r_wanted_output = 1;
8640 	}
8641 	INP_WLOCK_ASSERT(tp->t_inpcb);
8642 	return (0);
8643 }
8644 
8645 /*
8646  * Here nothing is really faster, its just that we
8647  * have broken out the fast-data path also just like
8648  * the fast-ack. Return 1 if we processed the packet
8649  * return 0 if you need to take the "slow-path".
8650  */
8651 static int
8652 bbr_do_fastnewdata(struct mbuf *m, struct tcphdr *th, struct socket *so,
8653     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
8654     uint32_t tiwin, int32_t nxt_pkt)
8655 {
8656 	uint16_t nsegs;
8657 	int32_t newsize = 0;	/* automatic sockbuf scaling */
8658 	struct tcp_bbr *bbr;
8659 #ifdef NETFLIX_SB_LIMITS
8660 	u_int mcnt, appended;
8661 #endif
8662 #ifdef TCPDEBUG
8663 	/*
8664 	 * The size of tcp_saveipgen must be the size of the max ip header,
8665 	 * now IPv6.
8666 	 */
8667 	u_char tcp_saveipgen[IP6_HDR_LEN];
8668 	struct tcphdr tcp_savetcp;
8669 	short ostate = 0;
8670 
8671 #endif
8672 	/* On the hpts and we would have called output */
8673 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
8674 
8675 	/*
8676 	 * If last ACK falls within this segment's sequence numbers, record
8677 	 * the timestamp. NOTE that the test is modified according to the
8678 	 * latest proposal of the tcplw@cray.com list (Braden 1993/04/26).
8679 	 */
8680 	if (bbr->r_ctl.rc_resend != NULL) {
8681 		return (0);
8682 	}
8683 	if (tiwin && tiwin != tp->snd_wnd) {
8684 		return (0);
8685 	}
8686 	if (__predict_false((tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN)))) {
8687 		return (0);
8688 	}
8689 	if (__predict_false((to->to_flags & TOF_TS) &&
8690 	    (TSTMP_LT(to->to_tsval, tp->ts_recent)))) {
8691 		return (0);
8692 	}
8693 	if (__predict_false((th->th_ack != tp->snd_una))) {
8694 		return (0);
8695 	}
8696 	if (__predict_false(tlen > sbspace(&so->so_rcv))) {
8697 		return (0);
8698 	}
8699 	if ((to->to_flags & TOF_TS) != 0 &&
8700 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
8701 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
8702 		tp->ts_recent = to->to_tsval;
8703 	}
8704 	/*
8705 	 * This is a pure, in-sequence data packet with nothing on the
8706 	 * reassembly queue and we have enough buffer space to take it.
8707 	 */
8708 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
8709 
8710 #ifdef NETFLIX_SB_LIMITS
8711 	if (so->so_rcv.sb_shlim) {
8712 		mcnt = m_memcnt(m);
8713 		appended = 0;
8714 		if (counter_fo_get(so->so_rcv.sb_shlim, mcnt,
8715 		    CFO_NOSLEEP, NULL) == false) {
8716 			counter_u64_add(tcp_sb_shlim_fails, 1);
8717 			m_freem(m);
8718 			return (1);
8719 		}
8720 	}
8721 #endif
8722 	/* Clean receiver SACK report if present */
8723 	if (tp->rcv_numsacks)
8724 		tcp_clean_sackreport(tp);
8725 	KMOD_TCPSTAT_INC(tcps_preddat);
8726 	tp->rcv_nxt += tlen;
8727 	/*
8728 	 * Pull snd_wl1 up to prevent seq wrap relative to th_seq.
8729 	 */
8730 	tp->snd_wl1 = th->th_seq;
8731 	/*
8732 	 * Pull rcv_up up to prevent seq wrap relative to rcv_nxt.
8733 	 */
8734 	tp->rcv_up = tp->rcv_nxt;
8735 	KMOD_TCPSTAT_ADD(tcps_rcvpack, (int)nsegs);
8736 	KMOD_TCPSTAT_ADD(tcps_rcvbyte, tlen);
8737 #ifdef TCPDEBUG
8738 	if (so->so_options & SO_DEBUG)
8739 		tcp_trace(TA_INPUT, ostate, tp,
8740 		    (void *)tcp_saveipgen, &tcp_savetcp, 0);
8741 #endif
8742 	newsize = tcp_autorcvbuf(m, th, so, tp, tlen);
8743 
8744 	/* Add data to socket buffer. */
8745 	SOCKBUF_LOCK(&so->so_rcv);
8746 	if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
8747 		m_freem(m);
8748 	} else {
8749 		/*
8750 		 * Set new socket buffer size. Give up when limit is
8751 		 * reached.
8752 		 */
8753 		if (newsize)
8754 			if (!sbreserve_locked(&so->so_rcv,
8755 			    newsize, so, NULL))
8756 				so->so_rcv.sb_flags &= ~SB_AUTOSIZE;
8757 		m_adj(m, drop_hdrlen);	/* delayed header drop */
8758 
8759 #ifdef NETFLIX_SB_LIMITS
8760 		appended =
8761 #endif
8762 			sbappendstream_locked(&so->so_rcv, m, 0);
8763 		ctf_calc_rwin(so, tp);
8764 	}
8765 	/* NB: sorwakeup_locked() does an implicit unlock. */
8766 	sorwakeup_locked(so);
8767 #ifdef NETFLIX_SB_LIMITS
8768 	if (so->so_rcv.sb_shlim && mcnt != appended)
8769 		counter_fo_release(so->so_rcv.sb_shlim, mcnt - appended);
8770 #endif
8771 	if (DELAY_ACK(tp, bbr, nsegs)) {
8772 		bbr->bbr_segs_rcvd += max(1, nsegs);
8773 		tp->t_flags |= TF_DELACK;
8774 		bbr_timer_cancel(bbr, __LINE__, bbr->r_ctl.rc_rcvtime);
8775 	} else {
8776 		bbr->r_wanted_output = 1;
8777 		tp->t_flags |= TF_ACKNOW;
8778 	}
8779 	return (1);
8780 }
8781 
8782 /*
8783  * This subfunction is used to try to highly optimize the
8784  * fast path. We again allow window updates that are
8785  * in sequence to remain in the fast-path. We also add
8786  * in the __predict's to attempt to help the compiler.
8787  * Note that if we return a 0, then we can *not* process
8788  * it and the caller should push the packet into the
8789  * slow-path. If we return 1, then all is well and
8790  * the packet is fully processed.
8791  */
8792 static int
8793 bbr_fastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
8794     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
8795     uint32_t tiwin, int32_t nxt_pkt)
8796 {
8797 	int32_t acked;
8798 	uint16_t nsegs;
8799 	uint32_t sack_changed;
8800 #ifdef TCPDEBUG
8801 	/*
8802 	 * The size of tcp_saveipgen must be the size of the max ip header,
8803 	 * now IPv6.
8804 	 */
8805 	u_char tcp_saveipgen[IP6_HDR_LEN];
8806 	struct tcphdr tcp_savetcp;
8807 	short ostate = 0;
8808 
8809 #endif
8810 	uint32_t prev_acked = 0;
8811 	struct tcp_bbr *bbr;
8812 
8813 	if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
8814 		/* Old ack, behind (or duplicate to) the last one rcv'd */
8815 		return (0);
8816 	}
8817 	if (__predict_false(SEQ_GT(th->th_ack, tp->snd_max))) {
8818 		/* Above what we have sent? */
8819 		return (0);
8820 	}
8821 	if (__predict_false(tiwin == 0)) {
8822 		/* zero window */
8823 		return (0);
8824 	}
8825 	if (__predict_false(tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN))) {
8826 		/* We need a SYN or a FIN, unlikely.. */
8827 		return (0);
8828 	}
8829 	if ((to->to_flags & TOF_TS) && __predict_false(TSTMP_LT(to->to_tsval, tp->ts_recent))) {
8830 		/* Timestamp is behind .. old ack with seq wrap? */
8831 		return (0);
8832 	}
8833 	if (__predict_false(IN_RECOVERY(tp->t_flags))) {
8834 		/* Still recovering */
8835 		return (0);
8836 	}
8837 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
8838 	if (__predict_false(bbr->r_ctl.rc_resend != NULL)) {
8839 		/* We are retransmitting */
8840 		return (0);
8841 	}
8842 	if (__predict_false(bbr->rc_in_persist != 0)) {
8843 		/* In persist mode */
8844 		return (0);
8845 	}
8846 	if (bbr->r_ctl.rc_sacked) {
8847 		/* We have sack holes on our scoreboard */
8848 		return (0);
8849 	}
8850 	/* Ok if we reach here, we can process a fast-ack */
8851 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
8852 	sack_changed = bbr_log_ack(tp, to, th, &prev_acked);
8853 	/*
8854 	 * We never detect loss in fast ack [we can't
8855 	 * have a sack and can't be in recovery so
8856 	 * we always pass 0 (nothing detected)].
8857 	 */
8858 	bbr_lt_bw_sampling(bbr, bbr->r_ctl.rc_rcvtime, 0);
8859 	/* Did the window get updated? */
8860 	if (tiwin != tp->snd_wnd) {
8861 		tp->snd_wnd = tiwin;
8862 		tp->snd_wl1 = th->th_seq;
8863 		if (tp->snd_wnd > tp->max_sndwnd)
8864 			tp->max_sndwnd = tp->snd_wnd;
8865 	}
8866 	/* Do we need to exit persists? */
8867 	if ((bbr->rc_in_persist != 0) &&
8868 	    (tp->snd_wnd >= min((bbr->r_ctl.rc_high_rwnd/2),
8869 			       bbr_minseg(bbr)))) {
8870 		bbr_exit_persist(tp, bbr, bbr->r_ctl.rc_rcvtime, __LINE__);
8871 		bbr->r_wanted_output = 1;
8872 	}
8873 	/* Do we need to enter persists? */
8874 	if ((bbr->rc_in_persist == 0) &&
8875 	    (tp->snd_wnd < min((bbr->r_ctl.rc_high_rwnd/2), bbr_minseg(bbr))) &&
8876 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
8877 	    (tp->snd_max == tp->snd_una) &&
8878 	    sbavail(&tp->t_inpcb->inp_socket->so_snd) &&
8879 	    (sbavail(&tp->t_inpcb->inp_socket->so_snd) > tp->snd_wnd)) {
8880 		/* No send window.. we must enter persist */
8881 		bbr_enter_persist(tp, bbr, bbr->r_ctl.rc_rcvtime, __LINE__);
8882 	}
8883 	/*
8884 	 * If last ACK falls within this segment's sequence numbers, record
8885 	 * the timestamp. NOTE that the test is modified according to the
8886 	 * latest proposal of the tcplw@cray.com list (Braden 1993/04/26).
8887 	 */
8888 	if ((to->to_flags & TOF_TS) != 0 &&
8889 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
8890 		tp->ts_recent_age = bbr->r_ctl.rc_rcvtime;
8891 		tp->ts_recent = to->to_tsval;
8892 	}
8893 	/*
8894 	 * This is a pure ack for outstanding data.
8895 	 */
8896 	KMOD_TCPSTAT_INC(tcps_predack);
8897 
8898 	/*
8899 	 * "bad retransmit" recovery.
8900 	 */
8901 	if (tp->t_flags & TF_PREVVALID) {
8902 		tp->t_flags &= ~TF_PREVVALID;
8903 		if (tp->t_rxtshift == 1 &&
8904 		    (int)(ticks - tp->t_badrxtwin) < 0)
8905 			bbr_cong_signal(tp, th, CC_RTO_ERR, NULL);
8906 	}
8907 	/*
8908 	 * Recalculate the transmit timer / rtt.
8909 	 *
8910 	 * Some boxes send broken timestamp replies during the SYN+ACK
8911 	 * phase, ignore timestamps of 0 or we could calculate a huge RTT
8912 	 * and blow up the retransmit timer.
8913 	 */
8914 	acked = BYTES_THIS_ACK(tp, th);
8915 
8916 #ifdef TCP_HHOOK
8917 	/* Run HHOOK_TCP_ESTABLISHED_IN helper hooks. */
8918 	hhook_run_tcp_est_in(tp, th, to);
8919 #endif
8920 
8921 	KMOD_TCPSTAT_ADD(tcps_rcvackpack, (int)nsegs);
8922 	KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
8923 	sbdrop(&so->so_snd, acked);
8924 
8925 	if (SEQ_GT(th->th_ack, tp->snd_una))
8926 		bbr_collapse_rtt(tp, bbr, TCP_REXMTVAL(tp));
8927 	tp->snd_una = th->th_ack;
8928 	if (tp->snd_wnd < ctf_outstanding(tp))
8929 		/* The peer collapsed its window on us */
8930 		bbr_collapsed_window(bbr);
8931 	else if (bbr->rc_has_collapsed)
8932 		bbr_un_collapse_window(bbr);
8933 
8934 	if (SEQ_GT(tp->snd_una, tp->snd_recover)) {
8935 		tp->snd_recover = tp->snd_una;
8936 	}
8937 	bbr_ack_received(tp, bbr, th, acked, sack_changed, prev_acked, __LINE__, 0);
8938 	/*
8939 	 * Pull snd_wl2 up to prevent seq wrap relative to th_ack.
8940 	 */
8941 	tp->snd_wl2 = th->th_ack;
8942 	m_freem(m);
8943 	/*
8944 	 * If all outstanding data are acked, stop retransmit timer,
8945 	 * otherwise restart timer using current (possibly backed-off)
8946 	 * value. If process is waiting for space, wakeup/selwakeup/signal.
8947 	 * If data are ready to send, let tcp_output decide between more
8948 	 * output or persist.
8949 	 */
8950 #ifdef TCPDEBUG
8951 	if (so->so_options & SO_DEBUG)
8952 		tcp_trace(TA_INPUT, ostate, tp,
8953 		    (void *)tcp_saveipgen,
8954 		    &tcp_savetcp, 0);
8955 #endif
8956 	/* Wake up the socket if we have room to write more */
8957 	sowwakeup(so);
8958 	if (tp->snd_una == tp->snd_max) {
8959 		/* Nothing left outstanding */
8960 		bbr_log_progress_event(bbr, tp, ticks, PROGRESS_CLEAR, __LINE__);
8961 		if (sbavail(&tp->t_inpcb->inp_socket->so_snd) == 0)
8962 			bbr->rc_tp->t_acktime = 0;
8963 		bbr_timer_cancel(bbr, __LINE__, bbr->r_ctl.rc_rcvtime);
8964 		if (bbr->rc_in_persist == 0) {
8965 			bbr->r_ctl.rc_went_idle_time = bbr->r_ctl.rc_rcvtime;
8966 		}
8967 		sack_filter_clear(&bbr->r_ctl.bbr_sf, tp->snd_una);
8968 		bbr_log_ack_clear(bbr, bbr->r_ctl.rc_rcvtime);
8969 		/*
8970 		 * We invalidate the last ack here since we
8971 		 * don't want to transfer forward the time
8972 		 * for our sum's calculations.
8973 		 */
8974 		bbr->r_wanted_output = 1;
8975 	}
8976 	if (sbavail(&so->so_snd)) {
8977 		bbr->r_wanted_output = 1;
8978 	}
8979 	return (1);
8980 }
8981 
8982 /*
8983  * Return value of 1, the TCB is unlocked and most
8984  * likely gone, return value of 0, the TCB is still
8985  * locked.
8986  */
8987 static int
8988 bbr_do_syn_sent(struct mbuf *m, struct tcphdr *th, struct socket *so,
8989     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
8990     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
8991 {
8992 	int32_t todrop;
8993 	int32_t ourfinisacked = 0;
8994 	struct tcp_bbr *bbr;
8995 	int32_t ret_val = 0;
8996 
8997 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
8998 	ctf_calc_rwin(so, tp);
8999 	/*
9000 	 * If the state is SYN_SENT: if seg contains an ACK, but not for our
9001 	 * SYN, drop the input. if seg contains a RST, then drop the
9002 	 * connection. if seg does not contain SYN, then drop it. Otherwise
9003 	 * this is an acceptable SYN segment initialize tp->rcv_nxt and
9004 	 * tp->irs if seg contains ack then advance tp->snd_una. BRR does
9005 	 * not support ECN so we will not say we are capable. if SYN has
9006 	 * been acked change to ESTABLISHED else SYN_RCVD state arrange for
9007 	 * segment to be acked (eventually) continue processing rest of
9008 	 * data/controls, beginning with URG
9009 	 */
9010 	if ((thflags & TH_ACK) &&
9011 	    (SEQ_LEQ(th->th_ack, tp->iss) ||
9012 	    SEQ_GT(th->th_ack, tp->snd_max))) {
9013 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9014 		return (1);
9015 	}
9016 	if ((thflags & (TH_ACK | TH_RST)) == (TH_ACK | TH_RST)) {
9017 		TCP_PROBE5(connect__refused, NULL, tp,
9018 		    mtod(m, const char *), tp, th);
9019 		tp = tcp_drop(tp, ECONNREFUSED);
9020 		ctf_do_drop(m, tp);
9021 		return (1);
9022 	}
9023 	if (thflags & TH_RST) {
9024 		ctf_do_drop(m, tp);
9025 		return (1);
9026 	}
9027 	if (!(thflags & TH_SYN)) {
9028 		ctf_do_drop(m, tp);
9029 		return (1);
9030 	}
9031 	tp->irs = th->th_seq;
9032 	tcp_rcvseqinit(tp);
9033 	if (thflags & TH_ACK) {
9034 		int tfo_partial = 0;
9035 
9036 		KMOD_TCPSTAT_INC(tcps_connects);
9037 		soisconnected(so);
9038 #ifdef MAC
9039 		mac_socketpeer_set_from_mbuf(m, so);
9040 #endif
9041 		/* Do window scaling on this connection? */
9042 		if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
9043 		    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
9044 			tp->rcv_scale = tp->request_r_scale;
9045 		}
9046 		tp->rcv_adv += min(tp->rcv_wnd,
9047 		    TCP_MAXWIN << tp->rcv_scale);
9048 		/*
9049 		 * If not all the data that was sent in the TFO SYN
9050 		 * has been acked, resend the remainder right away.
9051 		 */
9052 		if (IS_FASTOPEN(tp->t_flags) &&
9053 		    (tp->snd_una != tp->snd_max)) {
9054 			tp->snd_nxt = th->th_ack;
9055 			tfo_partial = 1;
9056 		}
9057 		/*
9058 		 * If there's data, delay ACK; if there's also a FIN ACKNOW
9059 		 * will be turned on later.
9060 		 */
9061 		if (DELAY_ACK(tp, bbr, 1) && tlen != 0 && (tfo_partial == 0)) {
9062 			bbr->bbr_segs_rcvd += 1;
9063 			tp->t_flags |= TF_DELACK;
9064 			bbr_timer_cancel(bbr, __LINE__, bbr->r_ctl.rc_rcvtime);
9065 		} else {
9066 			bbr->r_wanted_output = 1;
9067 			tp->t_flags |= TF_ACKNOW;
9068 		}
9069 		if (SEQ_GT(th->th_ack, tp->iss)) {
9070 			/*
9071 			 * The SYN is acked
9072 			 * handle it specially.
9073 			 */
9074 			bbr_log_syn(tp, to);
9075 		}
9076 		if (SEQ_GT(th->th_ack, tp->snd_una)) {
9077 			/*
9078 			 * We advance snd_una for the
9079 			 * fast open case. If th_ack is
9080 			 * acknowledging data beyond
9081 			 * snd_una we can't just call
9082 			 * ack-processing since the
9083 			 * data stream in our send-map
9084 			 * will start at snd_una + 1 (one
9085 			 * beyond the SYN). If its just
9086 			 * equal we don't need to do that
9087 			 * and there is no send_map.
9088 			 */
9089 			tp->snd_una++;
9090 		}
9091 		/*
9092 		 * Received <SYN,ACK> in SYN_SENT[*] state. Transitions:
9093 		 * SYN_SENT  --> ESTABLISHED SYN_SENT* --> FIN_WAIT_1
9094 		 */
9095 		tp->t_starttime = ticks;
9096 		if (tp->t_flags & TF_NEEDFIN) {
9097 			tcp_state_change(tp, TCPS_FIN_WAIT_1);
9098 			tp->t_flags &= ~TF_NEEDFIN;
9099 			thflags &= ~TH_SYN;
9100 		} else {
9101 			tcp_state_change(tp, TCPS_ESTABLISHED);
9102 			TCP_PROBE5(connect__established, NULL, tp,
9103 			    mtod(m, const char *), tp, th);
9104 			cc_conn_init(tp);
9105 		}
9106 	} else {
9107 		/*
9108 		 * Received initial SYN in SYN-SENT[*] state => simultaneous
9109 		 * open.  If segment contains CC option and there is a
9110 		 * cached CC, apply TAO test. If it succeeds, connection is *
9111 		 * half-synchronized. Otherwise, do 3-way handshake:
9112 		 * SYN-SENT -> SYN-RECEIVED SYN-SENT* -> SYN-RECEIVED* If
9113 		 * there was no CC option, clear cached CC value.
9114 		 */
9115 		tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
9116 		tcp_state_change(tp, TCPS_SYN_RECEIVED);
9117 	}
9118 	INP_WLOCK_ASSERT(tp->t_inpcb);
9119 	/*
9120 	 * Advance th->th_seq to correspond to first data byte. If data,
9121 	 * trim to stay within window, dropping FIN if necessary.
9122 	 */
9123 	th->th_seq++;
9124 	if (tlen > tp->rcv_wnd) {
9125 		todrop = tlen - tp->rcv_wnd;
9126 		m_adj(m, -todrop);
9127 		tlen = tp->rcv_wnd;
9128 		thflags &= ~TH_FIN;
9129 		KMOD_TCPSTAT_INC(tcps_rcvpackafterwin);
9130 		KMOD_TCPSTAT_ADD(tcps_rcvbyteafterwin, todrop);
9131 	}
9132 	tp->snd_wl1 = th->th_seq - 1;
9133 	tp->rcv_up = th->th_seq;
9134 	/*
9135 	 * Client side of transaction: already sent SYN and data. If the
9136 	 * remote host used T/TCP to validate the SYN, our data will be
9137 	 * ACK'd; if so, enter normal data segment processing in the middle
9138 	 * of step 5, ack processing. Otherwise, goto step 6.
9139 	 */
9140 	if (thflags & TH_ACK) {
9141 		if ((to->to_flags & TOF_TS) != 0) {
9142 			uint32_t t, rtt;
9143 
9144 			t = tcp_tv_to_mssectick(&bbr->rc_tv);
9145 			if (TSTMP_GEQ(t, to->to_tsecr)) {
9146 				rtt = t - to->to_tsecr;
9147 				if (rtt == 0) {
9148 					rtt = 1;
9149 				}
9150 				rtt *= MS_IN_USEC;
9151 				tcp_bbr_xmit_timer(bbr, rtt, 0, 0, 0);
9152 				apply_filter_min_small(&bbr->r_ctl.rc_rttprop,
9153 						       rtt, bbr->r_ctl.rc_rcvtime);
9154 			}
9155 		}
9156 		if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val))
9157 			return (ret_val);
9158 		/* We may have changed to FIN_WAIT_1 above */
9159 		if (tp->t_state == TCPS_FIN_WAIT_1) {
9160 			/*
9161 			 * In FIN_WAIT_1 STATE in addition to the processing
9162 			 * for the ESTABLISHED state if our FIN is now
9163 			 * acknowledged then enter FIN_WAIT_2.
9164 			 */
9165 			if (ourfinisacked) {
9166 				/*
9167 				 * If we can't receive any more data, then
9168 				 * closing user can proceed. Starting the
9169 				 * timer is contrary to the specification,
9170 				 * but if we don't get a FIN we'll hang
9171 				 * forever.
9172 				 *
9173 				 * XXXjl: we should release the tp also, and
9174 				 * use a compressed state.
9175 				 */
9176 				if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
9177 					soisdisconnected(so);
9178 					tcp_timer_activate(tp, TT_2MSL,
9179 					    (tcp_fast_finwait2_recycle ?
9180 					    tcp_finwait2_timeout :
9181 					    TP_MAXIDLE(tp)));
9182 				}
9183 				tcp_state_change(tp, TCPS_FIN_WAIT_2);
9184 			}
9185 		}
9186 	}
9187 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9188 	    tiwin, thflags, nxt_pkt));
9189 }
9190 
9191 /*
9192  * Return value of 1, the TCB is unlocked and most
9193  * likely gone, return value of 0, the TCB is still
9194  * locked.
9195  */
9196 static int
9197 bbr_do_syn_recv(struct mbuf *m, struct tcphdr *th, struct socket *so,
9198 		struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9199 		uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
9200 {
9201 	int32_t ourfinisacked = 0;
9202 	int32_t ret_val;
9203 	struct tcp_bbr *bbr;
9204 
9205 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9206 	ctf_calc_rwin(so, tp);
9207 	if ((thflags & TH_ACK) &&
9208 	    (SEQ_LEQ(th->th_ack, tp->snd_una) ||
9209 	     SEQ_GT(th->th_ack, tp->snd_max))) {
9210 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9211 		return (1);
9212 	}
9213 	if (IS_FASTOPEN(tp->t_flags)) {
9214 		/*
9215 		 * When a TFO connection is in SYN_RECEIVED, the only valid
9216 		 * packets are the initial SYN, a retransmit/copy of the
9217 		 * initial SYN (possibly with a subset of the original
9218 		 * data), a valid ACK, a FIN, or a RST.
9219 		 */
9220 		if ((thflags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) {
9221 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9222 			return (1);
9223 		} else if (thflags & TH_SYN) {
9224 			/* non-initial SYN is ignored */
9225 			if ((bbr->r_ctl.rc_hpts_flags & PACE_TMR_RXT) ||
9226 			    (bbr->r_ctl.rc_hpts_flags & PACE_TMR_TLP) ||
9227 			    (bbr->r_ctl.rc_hpts_flags & PACE_TMR_RACK)) {
9228 				ctf_do_drop(m, NULL);
9229 				return (0);
9230 			}
9231 		} else if (!(thflags & (TH_ACK | TH_FIN | TH_RST))) {
9232 			ctf_do_drop(m, NULL);
9233 			return (0);
9234 		}
9235 	}
9236 	if ((thflags & TH_RST) ||
9237 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9238 		return (ctf_process_rst(m, th, so, tp));
9239 	/*
9240 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9241 	 * it's less than ts_recent, drop it.
9242 	 */
9243 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9244 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9245 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9246 			return (ret_val);
9247 	}
9248 	/*
9249 	 * In the SYN-RECEIVED state, validate that the packet belongs to
9250 	 * this connection before trimming the data to fit the receive
9251 	 * window.  Check the sequence number versus IRS since we know the
9252 	 * sequence numbers haven't wrapped.  This is a partial fix for the
9253 	 * "LAND" DoS attack.
9254 	 */
9255 	if (SEQ_LT(th->th_seq, tp->irs)) {
9256 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9257 		return (1);
9258 	}
9259 	INP_WLOCK_ASSERT(tp->t_inpcb);
9260 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9261 		return (ret_val);
9262 	}
9263 	/*
9264 	 * If last ACK falls within this segment's sequence numbers, record
9265 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9266 	 * from the latest proposal of the tcplw@cray.com list (Braden
9267 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9268 	 * with our earlier PAWS tests, so this check should be solely
9269 	 * predicated on the sequence space of this segment. 3) That we
9270 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9271 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9272 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9273 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9274 	 * p.869. In such cases, we can still calculate the RTT correctly
9275 	 * when RCV.NXT == Last.ACK.Sent.
9276 	 */
9277 	if ((to->to_flags & TOF_TS) != 0 &&
9278 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9279 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9280 		    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9281 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9282 		tp->ts_recent = to->to_tsval;
9283 	}
9284 	tp->snd_wnd = tiwin;
9285 	/*
9286 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9287 	 * is on (half-synchronized state), then queue data for later
9288 	 * processing; else drop segment and return.
9289 	 */
9290 	if ((thflags & TH_ACK) == 0) {
9291 		if (IS_FASTOPEN(tp->t_flags)) {
9292 			cc_conn_init(tp);
9293 		}
9294 		return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9295 					 tiwin, thflags, nxt_pkt));
9296 	}
9297 	KMOD_TCPSTAT_INC(tcps_connects);
9298 	soisconnected(so);
9299 	/* Do window scaling? */
9300 	if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
9301 	    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
9302 		tp->rcv_scale = tp->request_r_scale;
9303 	}
9304 	/*
9305 	 * ok for the first time in lets see if we can use the ts to figure
9306 	 * out what the initial RTT was.
9307 	 */
9308 	if ((to->to_flags & TOF_TS) != 0) {
9309 		uint32_t t, rtt;
9310 
9311 		t = tcp_tv_to_mssectick(&bbr->rc_tv);
9312 		if (TSTMP_GEQ(t, to->to_tsecr)) {
9313 			rtt = t - to->to_tsecr;
9314 			if (rtt == 0) {
9315 				rtt = 1;
9316 			}
9317 			rtt *= MS_IN_USEC;
9318 			tcp_bbr_xmit_timer(bbr, rtt, 0, 0, 0);
9319 			apply_filter_min_small(&bbr->r_ctl.rc_rttprop, rtt, bbr->r_ctl.rc_rcvtime);
9320 		}
9321 	}
9322 	/* Drop off any SYN in the send map (probably not there)  */
9323 	if (thflags & TH_ACK)
9324 		bbr_log_syn(tp, to);
9325 	if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) {
9326 
9327 		tcp_fastopen_decrement_counter(tp->t_tfo_pending);
9328 		tp->t_tfo_pending = NULL;
9329 		/*
9330 		 * Account for the ACK of our SYN prior to regular
9331 		 * ACK processing below.
9332 		 */
9333 		tp->snd_una++;
9334 	}
9335 	/*
9336 	 * Make transitions: SYN-RECEIVED  -> ESTABLISHED SYN-RECEIVED* ->
9337 	 * FIN-WAIT-1
9338 	 */
9339 	tp->t_starttime = ticks;
9340 	if (tp->t_flags & TF_NEEDFIN) {
9341 		tcp_state_change(tp, TCPS_FIN_WAIT_1);
9342 		tp->t_flags &= ~TF_NEEDFIN;
9343 	} else {
9344 		tcp_state_change(tp, TCPS_ESTABLISHED);
9345 		TCP_PROBE5(accept__established, NULL, tp,
9346 			   mtod(m, const char *), tp, th);
9347 		/*
9348 		 * TFO connections call cc_conn_init() during SYN
9349 		 * processing.  Calling it again here for such connections
9350 		 * is not harmless as it would undo the snd_cwnd reduction
9351 		 * that occurs when a TFO SYN|ACK is retransmitted.
9352 		 */
9353 		if (!IS_FASTOPEN(tp->t_flags))
9354 			cc_conn_init(tp);
9355 	}
9356 	/*
9357 	 * If segment contains data or ACK, will call tcp_reass() later; if
9358 	 * not, do so now to pass queued data to user.
9359 	 */
9360 	if (tlen == 0 && (thflags & TH_FIN) == 0)
9361 		(void)tcp_reass(tp, (struct tcphdr *)0, NULL, 0,
9362 			(struct mbuf *)0);
9363 	tp->snd_wl1 = th->th_seq - 1;
9364 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
9365 		return (ret_val);
9366 	}
9367 	if (tp->t_state == TCPS_FIN_WAIT_1) {
9368 		/* We could have went to FIN_WAIT_1 (or EST) above */
9369 		/*
9370 		 * In FIN_WAIT_1 STATE in addition to the processing for the
9371 		 * ESTABLISHED state if our FIN is now acknowledged then
9372 		 * enter FIN_WAIT_2.
9373 		 */
9374 		if (ourfinisacked) {
9375 			/*
9376 			 * If we can't receive any more data, then closing
9377 			 * user can proceed. Starting the timer is contrary
9378 			 * to the specification, but if we don't get a FIN
9379 			 * we'll hang forever.
9380 			 *
9381 			 * XXXjl: we should release the tp also, and use a
9382 			 * compressed state.
9383 			 */
9384 			if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
9385 				soisdisconnected(so);
9386 				tcp_timer_activate(tp, TT_2MSL,
9387 						   (tcp_fast_finwait2_recycle ?
9388 						    tcp_finwait2_timeout :
9389 						    TP_MAXIDLE(tp)));
9390 			}
9391 			tcp_state_change(tp, TCPS_FIN_WAIT_2);
9392 		}
9393 	}
9394 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9395 				 tiwin, thflags, nxt_pkt));
9396 }
9397 
9398 /*
9399  * Return value of 1, the TCB is unlocked and most
9400  * likely gone, return value of 0, the TCB is still
9401  * locked.
9402  */
9403 static int
9404 bbr_do_established(struct mbuf *m, struct tcphdr *th, struct socket *so,
9405     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9406     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
9407 {
9408 	struct tcp_bbr *bbr;
9409 	int32_t ret_val;
9410 
9411 	/*
9412 	 * Header prediction: check for the two common cases of a
9413 	 * uni-directional data xfer.  If the packet has no control flags,
9414 	 * is in-sequence, the window didn't change and we're not
9415 	 * retransmitting, it's a candidate.  If the length is zero and the
9416 	 * ack moved forward, we're the sender side of the xfer.  Just free
9417 	 * the data acked & wake any higher level process that was blocked
9418 	 * waiting for space.  If the length is non-zero and the ack didn't
9419 	 * move, we're the receiver side.  If we're getting packets in-order
9420 	 * (the reassembly queue is empty), add the data toc The socket
9421 	 * buffer and note that we need a delayed ack. Make sure that the
9422 	 * hidden state-flags are also off. Since we check for
9423 	 * TCPS_ESTABLISHED first, it can only be TH_NEEDSYN.
9424 	 */
9425 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9426 	if (bbr->r_ctl.rc_delivered < (4 * tp->t_maxseg)) {
9427 		/*
9428 		 * If we have delived under 4 segments increase the initial
9429 		 * window if raised by the peer. We use this to determine
9430 		 * dynamic and static rwnd's at the end of a connection.
9431 		 */
9432 		bbr->r_ctl.rc_init_rwnd = max(tiwin, tp->snd_wnd);
9433 	}
9434 	if (__predict_true(((to->to_flags & TOF_SACK) == 0)) &&
9435 	    __predict_true((thflags & (TH_SYN | TH_FIN | TH_RST | TH_URG | TH_ACK)) == TH_ACK) &&
9436 	    __predict_true(SEGQ_EMPTY(tp)) &&
9437 	    __predict_true(th->th_seq == tp->rcv_nxt)) {
9438 		if (tlen == 0) {
9439 			if (bbr_fastack(m, th, so, tp, to, drop_hdrlen, tlen,
9440 			    tiwin, nxt_pkt)) {
9441 				return (0);
9442 			}
9443 		} else {
9444 			if (bbr_do_fastnewdata(m, th, so, tp, to, drop_hdrlen, tlen,
9445 			    tiwin, nxt_pkt)) {
9446 				return (0);
9447 			}
9448 		}
9449 	}
9450 	ctf_calc_rwin(so, tp);
9451 
9452 	if ((thflags & TH_RST) ||
9453 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9454 		return (ctf_process_rst(m, th, so, tp));
9455 	/*
9456 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9457 	 * synchronized state.
9458 	 */
9459 	if (thflags & TH_SYN) {
9460 		ctf_challenge_ack(m, th, tp, &ret_val);
9461 		return (ret_val);
9462 	}
9463 	/*
9464 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9465 	 * it's less than ts_recent, drop it.
9466 	 */
9467 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9468 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9469 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9470 			return (ret_val);
9471 	}
9472 	INP_WLOCK_ASSERT(tp->t_inpcb);
9473 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9474 		return (ret_val);
9475 	}
9476 	/*
9477 	 * If last ACK falls within this segment's sequence numbers, record
9478 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9479 	 * from the latest proposal of the tcplw@cray.com list (Braden
9480 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9481 	 * with our earlier PAWS tests, so this check should be solely
9482 	 * predicated on the sequence space of this segment. 3) That we
9483 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9484 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9485 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9486 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9487 	 * p.869. In such cases, we can still calculate the RTT correctly
9488 	 * when RCV.NXT == Last.ACK.Sent.
9489 	 */
9490 	if ((to->to_flags & TOF_TS) != 0 &&
9491 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9492 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9493 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9494 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9495 		tp->ts_recent = to->to_tsval;
9496 	}
9497 	/*
9498 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9499 	 * is on (half-synchronized state), then queue data for later
9500 	 * processing; else drop segment and return.
9501 	 */
9502 	if ((thflags & TH_ACK) == 0) {
9503 		if (tp->t_flags & TF_NEEDSYN) {
9504 			return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9505 			    tiwin, thflags, nxt_pkt));
9506 		} else if (tp->t_flags & TF_ACKNOW) {
9507 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9508 			bbr->r_wanted_output = 1;
9509 			return (ret_val);
9510 		} else {
9511 			ctf_do_drop(m, NULL);
9512 			return (0);
9513 		}
9514 	}
9515 	/*
9516 	 * Ack processing.
9517 	 */
9518 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) {
9519 		return (ret_val);
9520 	}
9521 	if (sbavail(&so->so_snd)) {
9522 		if (bbr_progress_timeout_check(bbr)) {
9523 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9524 			return (1);
9525 		}
9526 	}
9527 	/* State changes only happen in bbr_process_data() */
9528 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9529 	    tiwin, thflags, nxt_pkt));
9530 }
9531 
9532 /*
9533  * Return value of 1, the TCB is unlocked and most
9534  * likely gone, return value of 0, the TCB is still
9535  * locked.
9536  */
9537 static int
9538 bbr_do_close_wait(struct mbuf *m, struct tcphdr *th, struct socket *so,
9539     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9540     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
9541 {
9542 	struct tcp_bbr *bbr;
9543 	int32_t ret_val;
9544 
9545 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9546 	ctf_calc_rwin(so, tp);
9547 	if ((thflags & TH_RST) ||
9548 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9549 		return (ctf_process_rst(m, th, so, tp));
9550 	/*
9551 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9552 	 * synchronized state.
9553 	 */
9554 	if (thflags & TH_SYN) {
9555 		ctf_challenge_ack(m, th, tp, &ret_val);
9556 		return (ret_val);
9557 	}
9558 	/*
9559 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9560 	 * it's less than ts_recent, drop it.
9561 	 */
9562 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9563 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9564 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9565 			return (ret_val);
9566 	}
9567 	INP_WLOCK_ASSERT(tp->t_inpcb);
9568 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9569 		return (ret_val);
9570 	}
9571 	/*
9572 	 * If last ACK falls within this segment's sequence numbers, record
9573 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9574 	 * from the latest proposal of the tcplw@cray.com list (Braden
9575 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9576 	 * with our earlier PAWS tests, so this check should be solely
9577 	 * predicated on the sequence space of this segment. 3) That we
9578 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9579 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9580 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9581 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9582 	 * p.869. In such cases, we can still calculate the RTT correctly
9583 	 * when RCV.NXT == Last.ACK.Sent.
9584 	 */
9585 	if ((to->to_flags & TOF_TS) != 0 &&
9586 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9587 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9588 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9589 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9590 		tp->ts_recent = to->to_tsval;
9591 	}
9592 	/*
9593 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9594 	 * is on (half-synchronized state), then queue data for later
9595 	 * processing; else drop segment and return.
9596 	 */
9597 	if ((thflags & TH_ACK) == 0) {
9598 		if (tp->t_flags & TF_NEEDSYN) {
9599 			return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9600 			    tiwin, thflags, nxt_pkt));
9601 		} else if (tp->t_flags & TF_ACKNOW) {
9602 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9603 			bbr->r_wanted_output = 1;
9604 			return (ret_val);
9605 		} else {
9606 			ctf_do_drop(m, NULL);
9607 			return (0);
9608 		}
9609 	}
9610 	/*
9611 	 * Ack processing.
9612 	 */
9613 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) {
9614 		return (ret_val);
9615 	}
9616 	if (sbavail(&so->so_snd)) {
9617 		if (bbr_progress_timeout_check(bbr)) {
9618 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9619 			return (1);
9620 		}
9621 	}
9622 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9623 	    tiwin, thflags, nxt_pkt));
9624 }
9625 
9626 static int
9627 bbr_check_data_after_close(struct mbuf *m, struct tcp_bbr *bbr,
9628     struct tcpcb *tp, int32_t * tlen, struct tcphdr *th, struct socket *so)
9629 {
9630 
9631 	if (bbr->rc_allow_data_af_clo == 0) {
9632 close_now:
9633 		tp = tcp_close(tp);
9634 		KMOD_TCPSTAT_INC(tcps_rcvafterclose);
9635 		ctf_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, (*tlen));
9636 		return (1);
9637 	}
9638 	if (sbavail(&so->so_snd) == 0)
9639 		goto close_now;
9640 	/* Ok we allow data that is ignored and a followup reset */
9641 	tp->rcv_nxt = th->th_seq + *tlen;
9642 	tp->t_flags2 |= TF2_DROP_AF_DATA;
9643 	bbr->r_wanted_output = 1;
9644 	*tlen = 0;
9645 	return (0);
9646 }
9647 
9648 /*
9649  * Return value of 1, the TCB is unlocked and most
9650  * likely gone, return value of 0, the TCB is still
9651  * locked.
9652  */
9653 static int
9654 bbr_do_fin_wait_1(struct mbuf *m, struct tcphdr *th, struct socket *so,
9655     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9656     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
9657 {
9658 	int32_t ourfinisacked = 0;
9659 	int32_t ret_val;
9660 	struct tcp_bbr *bbr;
9661 
9662 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9663 	ctf_calc_rwin(so, tp);
9664 	if ((thflags & TH_RST) ||
9665 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9666 		return (ctf_process_rst(m, th, so, tp));
9667 	/*
9668 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9669 	 * synchronized state.
9670 	 */
9671 	if (thflags & TH_SYN) {
9672 		ctf_challenge_ack(m, th, tp, &ret_val);
9673 		return (ret_val);
9674 	}
9675 	/*
9676 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9677 	 * it's less than ts_recent, drop it.
9678 	 */
9679 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9680 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9681 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9682 			return (ret_val);
9683 	}
9684 	INP_WLOCK_ASSERT(tp->t_inpcb);
9685 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9686 		return (ret_val);
9687 	}
9688 	/*
9689 	 * If new data are received on a connection after the user processes
9690 	 * are gone, then RST the other end.
9691 	 */
9692 	if ((so->so_state & SS_NOFDREF) && tlen) {
9693 		/*
9694 		 * We call a new function now so we might continue and setup
9695 		 * to reset at all data being ack'd.
9696 		 */
9697 		if (bbr_check_data_after_close(m, bbr, tp, &tlen, th, so))
9698 			return (1);
9699 	}
9700 	/*
9701 	 * If last ACK falls within this segment's sequence numbers, record
9702 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9703 	 * from the latest proposal of the tcplw@cray.com list (Braden
9704 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9705 	 * with our earlier PAWS tests, so this check should be solely
9706 	 * predicated on the sequence space of this segment. 3) That we
9707 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9708 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9709 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9710 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9711 	 * p.869. In such cases, we can still calculate the RTT correctly
9712 	 * when RCV.NXT == Last.ACK.Sent.
9713 	 */
9714 	if ((to->to_flags & TOF_TS) != 0 &&
9715 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9716 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9717 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9718 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9719 		tp->ts_recent = to->to_tsval;
9720 	}
9721 	/*
9722 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9723 	 * is on (half-synchronized state), then queue data for later
9724 	 * processing; else drop segment and return.
9725 	 */
9726 	if ((thflags & TH_ACK) == 0) {
9727 		if (tp->t_flags & TF_NEEDSYN) {
9728 			return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9729 			    tiwin, thflags, nxt_pkt));
9730 		} else if (tp->t_flags & TF_ACKNOW) {
9731 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9732 			bbr->r_wanted_output = 1;
9733 			return (ret_val);
9734 		} else {
9735 			ctf_do_drop(m, NULL);
9736 			return (0);
9737 		}
9738 	}
9739 	/*
9740 	 * Ack processing.
9741 	 */
9742 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
9743 		return (ret_val);
9744 	}
9745 	if (ourfinisacked) {
9746 		/*
9747 		 * If we can't receive any more data, then closing user can
9748 		 * proceed. Starting the timer is contrary to the
9749 		 * specification, but if we don't get a FIN we'll hang
9750 		 * forever.
9751 		 *
9752 		 * XXXjl: we should release the tp also, and use a
9753 		 * compressed state.
9754 		 */
9755 		if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
9756 			soisdisconnected(so);
9757 			tcp_timer_activate(tp, TT_2MSL,
9758 			    (tcp_fast_finwait2_recycle ?
9759 			    tcp_finwait2_timeout :
9760 			    TP_MAXIDLE(tp)));
9761 		}
9762 		tcp_state_change(tp, TCPS_FIN_WAIT_2);
9763 	}
9764 	if (sbavail(&so->so_snd)) {
9765 		if (bbr_progress_timeout_check(bbr)) {
9766 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9767 			return (1);
9768 		}
9769 	}
9770 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9771 	    tiwin, thflags, nxt_pkt));
9772 }
9773 
9774 /*
9775  * Return value of 1, the TCB is unlocked and most
9776  * likely gone, return value of 0, the TCB is still
9777  * locked.
9778  */
9779 static int
9780 bbr_do_closing(struct mbuf *m, struct tcphdr *th, struct socket *so,
9781     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9782     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
9783 {
9784 	int32_t ourfinisacked = 0;
9785 	int32_t ret_val;
9786 	struct tcp_bbr *bbr;
9787 
9788 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9789 	ctf_calc_rwin(so, tp);
9790 	if ((thflags & TH_RST) ||
9791 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9792 		return (ctf_process_rst(m, th, so, tp));
9793 	/*
9794 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9795 	 * synchronized state.
9796 	 */
9797 	if (thflags & TH_SYN) {
9798 		ctf_challenge_ack(m, th, tp, &ret_val);
9799 		return (ret_val);
9800 	}
9801 	/*
9802 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9803 	 * it's less than ts_recent, drop it.
9804 	 */
9805 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9806 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9807 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9808 			return (ret_val);
9809 	}
9810 	INP_WLOCK_ASSERT(tp->t_inpcb);
9811 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9812 		return (ret_val);
9813 	}
9814 	/*
9815 	 * If new data are received on a connection after the user processes
9816 	 * are gone, then RST the other end.
9817 	 */
9818 	if ((so->so_state & SS_NOFDREF) && tlen) {
9819 		/*
9820 		 * We call a new function now so we might continue and setup
9821 		 * to reset at all data being ack'd.
9822 		 */
9823 		if (bbr_check_data_after_close(m, bbr, tp, &tlen, th, so))
9824 			return (1);
9825 	}
9826 	/*
9827 	 * If last ACK falls within this segment's sequence numbers, record
9828 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9829 	 * from the latest proposal of the tcplw@cray.com list (Braden
9830 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9831 	 * with our earlier PAWS tests, so this check should be solely
9832 	 * predicated on the sequence space of this segment. 3) That we
9833 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9834 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9835 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9836 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9837 	 * p.869. In such cases, we can still calculate the RTT correctly
9838 	 * when RCV.NXT == Last.ACK.Sent.
9839 	 */
9840 	if ((to->to_flags & TOF_TS) != 0 &&
9841 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9842 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9843 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9844 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9845 		tp->ts_recent = to->to_tsval;
9846 	}
9847 	/*
9848 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9849 	 * is on (half-synchronized state), then queue data for later
9850 	 * processing; else drop segment and return.
9851 	 */
9852 	if ((thflags & TH_ACK) == 0) {
9853 		if (tp->t_flags & TF_NEEDSYN) {
9854 			return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9855 			    tiwin, thflags, nxt_pkt));
9856 		} else if (tp->t_flags & TF_ACKNOW) {
9857 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9858 			bbr->r_wanted_output = 1;
9859 			return (ret_val);
9860 		} else {
9861 			ctf_do_drop(m, NULL);
9862 			return (0);
9863 		}
9864 	}
9865 	/*
9866 	 * Ack processing.
9867 	 */
9868 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
9869 		return (ret_val);
9870 	}
9871 	if (ourfinisacked) {
9872 		tcp_twstart(tp);
9873 		m_freem(m);
9874 		return (1);
9875 	}
9876 	if (sbavail(&so->so_snd)) {
9877 		if (bbr_progress_timeout_check(bbr)) {
9878 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9879 			return (1);
9880 		}
9881 	}
9882 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9883 	    tiwin, thflags, nxt_pkt));
9884 }
9885 
9886 /*
9887  * Return value of 1, the TCB is unlocked and most
9888  * likely gone, return value of 0, the TCB is still
9889  * locked.
9890  */
9891 static int
9892 bbr_do_lastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
9893     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9894     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
9895 {
9896 	int32_t ourfinisacked = 0;
9897 	int32_t ret_val;
9898 	struct tcp_bbr *bbr;
9899 
9900 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9901 	ctf_calc_rwin(so, tp);
9902 	if ((thflags & TH_RST) ||
9903 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9904 		return (ctf_process_rst(m, th, so, tp));
9905 	/*
9906 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9907 	 * synchronized state.
9908 	 */
9909 	if (thflags & TH_SYN) {
9910 		ctf_challenge_ack(m, th, tp, &ret_val);
9911 		return (ret_val);
9912 	}
9913 	/*
9914 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9915 	 * it's less than ts_recent, drop it.
9916 	 */
9917 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9918 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9919 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9920 			return (ret_val);
9921 	}
9922 	INP_WLOCK_ASSERT(tp->t_inpcb);
9923 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9924 		return (ret_val);
9925 	}
9926 	/*
9927 	 * If new data are received on a connection after the user processes
9928 	 * are gone, then RST the other end.
9929 	 */
9930 	if ((so->so_state & SS_NOFDREF) && tlen) {
9931 		/*
9932 		 * We call a new function now so we might continue and setup
9933 		 * to reset at all data being ack'd.
9934 		 */
9935 		if (bbr_check_data_after_close(m, bbr, tp, &tlen, th, so))
9936 			return (1);
9937 	}
9938 	/*
9939 	 * If last ACK falls within this segment's sequence numbers, record
9940 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9941 	 * from the latest proposal of the tcplw@cray.com list (Braden
9942 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9943 	 * with our earlier PAWS tests, so this check should be solely
9944 	 * predicated on the sequence space of this segment. 3) That we
9945 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9946 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9947 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9948 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9949 	 * p.869. In such cases, we can still calculate the RTT correctly
9950 	 * when RCV.NXT == Last.ACK.Sent.
9951 	 */
9952 	if ((to->to_flags & TOF_TS) != 0 &&
9953 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9954 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9955 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9956 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9957 		tp->ts_recent = to->to_tsval;
9958 	}
9959 	/*
9960 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9961 	 * is on (half-synchronized state), then queue data for later
9962 	 * processing; else drop segment and return.
9963 	 */
9964 	if ((thflags & TH_ACK) == 0) {
9965 		if (tp->t_flags & TF_NEEDSYN) {
9966 			return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9967 			    tiwin, thflags, nxt_pkt));
9968 		} else if (tp->t_flags & TF_ACKNOW) {
9969 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9970 			bbr->r_wanted_output = 1;
9971 			return (ret_val);
9972 		} else {
9973 			ctf_do_drop(m, NULL);
9974 			return (0);
9975 		}
9976 	}
9977 	/*
9978 	 * case TCPS_LAST_ACK: Ack processing.
9979 	 */
9980 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
9981 		return (ret_val);
9982 	}
9983 	if (ourfinisacked) {
9984 		tp = tcp_close(tp);
9985 		ctf_do_drop(m, tp);
9986 		return (1);
9987 	}
9988 	if (sbavail(&so->so_snd)) {
9989 		if (bbr_progress_timeout_check(bbr)) {
9990 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9991 			return (1);
9992 		}
9993 	}
9994 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9995 	    tiwin, thflags, nxt_pkt));
9996 }
9997 
9998 
9999 /*
10000  * Return value of 1, the TCB is unlocked and most
10001  * likely gone, return value of 0, the TCB is still
10002  * locked.
10003  */
10004 static int
10005 bbr_do_fin_wait_2(struct mbuf *m, struct tcphdr *th, struct socket *so,
10006     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
10007     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
10008 {
10009 	int32_t ourfinisacked = 0;
10010 	int32_t ret_val;
10011 	struct tcp_bbr *bbr;
10012 
10013 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
10014 	ctf_calc_rwin(so, tp);
10015 	/* Reset receive buffer auto scaling when not in bulk receive mode. */
10016 	if ((thflags & TH_RST) ||
10017 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
10018 		return (ctf_process_rst(m, th, so, tp));
10019 
10020 	/*
10021 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
10022 	 * synchronized state.
10023 	 */
10024 	if (thflags & TH_SYN) {
10025 		ctf_challenge_ack(m, th, tp, &ret_val);
10026 		return (ret_val);
10027 	}
10028 	INP_WLOCK_ASSERT(tp->t_inpcb);
10029 	/*
10030 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
10031 	 * it's less than ts_recent, drop it.
10032 	 */
10033 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
10034 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
10035 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
10036 			return (ret_val);
10037 	}
10038 	INP_WLOCK_ASSERT(tp->t_inpcb);
10039 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
10040 		return (ret_val);
10041 	}
10042 	/*
10043 	 * If new data are received on a connection after the user processes
10044 	 * are gone, then we may RST the other end depending on the outcome
10045 	 * of bbr_check_data_after_close.
10046 	 */
10047 	if ((so->so_state & SS_NOFDREF) &&
10048 	    tlen) {
10049 		/*
10050 		 * We call a new function now so we might continue and setup
10051 		 * to reset at all data being ack'd.
10052 		 */
10053 		if (bbr_check_data_after_close(m, bbr, tp, &tlen, th, so))
10054 			return (1);
10055 	}
10056 	INP_WLOCK_ASSERT(tp->t_inpcb);
10057 	/*
10058 	 * If last ACK falls within this segment's sequence numbers, record
10059 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
10060 	 * from the latest proposal of the tcplw@cray.com list (Braden
10061 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
10062 	 * with our earlier PAWS tests, so this check should be solely
10063 	 * predicated on the sequence space of this segment. 3) That we
10064 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
10065 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
10066 	 * SEG.Len, This modified check allows us to overcome RFC1323's
10067 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
10068 	 * p.869. In such cases, we can still calculate the RTT correctly
10069 	 * when RCV.NXT == Last.ACK.Sent.
10070 	 */
10071 	INP_WLOCK_ASSERT(tp->t_inpcb);
10072 	if ((to->to_flags & TOF_TS) != 0 &&
10073 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
10074 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
10075 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
10076 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
10077 		tp->ts_recent = to->to_tsval;
10078 	}
10079 	/*
10080 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
10081 	 * is on (half-synchronized state), then queue data for later
10082 	 * processing; else drop segment and return.
10083 	 */
10084 	if ((thflags & TH_ACK) == 0) {
10085 		if (tp->t_flags & TF_NEEDSYN) {
10086 			return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
10087 			    tiwin, thflags, nxt_pkt));
10088 		} else if (tp->t_flags & TF_ACKNOW) {
10089 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
10090 			bbr->r_wanted_output = 1;
10091 			return (ret_val);
10092 		} else {
10093 			ctf_do_drop(m, NULL);
10094 			return (0);
10095 		}
10096 	}
10097 	/*
10098 	 * Ack processing.
10099 	 */
10100 	INP_WLOCK_ASSERT(tp->t_inpcb);
10101 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
10102 		return (ret_val);
10103 	}
10104 	if (sbavail(&so->so_snd)) {
10105 		if (bbr_progress_timeout_check(bbr)) {
10106 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
10107 			return (1);
10108 		}
10109 	}
10110 	INP_WLOCK_ASSERT(tp->t_inpcb);
10111 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
10112 	    tiwin, thflags, nxt_pkt));
10113 }
10114 
10115 static void
10116 bbr_stop_all_timers(struct tcpcb *tp)
10117 {
10118 	struct tcp_bbr *bbr;
10119 
10120 	/*
10121 	 * Assure no timers are running.
10122 	 */
10123 	if (tcp_timer_active(tp, TT_PERSIST)) {
10124 		/* We enter in persists, set the flag appropriately */
10125 		bbr = (struct tcp_bbr *)tp->t_fb_ptr;
10126 		bbr->rc_in_persist = 1;
10127 	}
10128 	tcp_timer_suspend(tp, TT_PERSIST);
10129 	tcp_timer_suspend(tp, TT_REXMT);
10130 	tcp_timer_suspend(tp, TT_KEEP);
10131 	tcp_timer_suspend(tp, TT_DELACK);
10132 }
10133 
10134 static void
10135 bbr_google_mode_on(struct tcp_bbr *bbr)
10136 {
10137 	bbr->rc_use_google = 1;
10138 	bbr->rc_no_pacing = 0;
10139 	bbr->r_ctl.bbr_google_discount = bbr_google_discount;
10140 	bbr->r_use_policer = bbr_policer_detection_enabled;
10141 	bbr->r_ctl.rc_probertt_int = (USECS_IN_SECOND * 10);
10142 	bbr->bbr_use_rack_cheat = 0;
10143 	bbr->r_ctl.rc_incr_tmrs = 0;
10144 	bbr->r_ctl.rc_inc_tcp_oh = 0;
10145 	bbr->r_ctl.rc_inc_ip_oh = 0;
10146 	bbr->r_ctl.rc_inc_enet_oh = 0;
10147 	reset_time(&bbr->r_ctl.rc_delrate,
10148 		   BBR_NUM_RTTS_FOR_GOOG_DEL_LIMIT);
10149 	reset_time_small(&bbr->r_ctl.rc_rttprop,
10150 			 (11 * USECS_IN_SECOND));
10151 	tcp_bbr_tso_size_check(bbr, tcp_get_usecs(&bbr->rc_tv));
10152 }
10153 
10154 static void
10155 bbr_google_mode_off(struct tcp_bbr *bbr)
10156 {
10157 	bbr->rc_use_google = 0;
10158 	bbr->r_ctl.bbr_google_discount = 0;
10159 	bbr->no_pacing_until = bbr_no_pacing_until;
10160 	bbr->r_use_policer = 0;
10161 	if (bbr->no_pacing_until)
10162 		bbr->rc_no_pacing = 1;
10163 	else
10164 		bbr->rc_no_pacing = 0;
10165 	if (bbr_use_rack_resend_cheat)
10166 		bbr->bbr_use_rack_cheat = 1;
10167 	else
10168 		bbr->bbr_use_rack_cheat = 0;
10169 	if (bbr_incr_timers)
10170 		bbr->r_ctl.rc_incr_tmrs = 1;
10171 	else
10172 		bbr->r_ctl.rc_incr_tmrs = 0;
10173 	if (bbr_include_tcp_oh)
10174 		bbr->r_ctl.rc_inc_tcp_oh = 1;
10175 	else
10176 		bbr->r_ctl.rc_inc_tcp_oh = 0;
10177 	if (bbr_include_ip_oh)
10178 		bbr->r_ctl.rc_inc_ip_oh = 1;
10179 	else
10180 		bbr->r_ctl.rc_inc_ip_oh = 0;
10181 	if (bbr_include_enet_oh)
10182 		bbr->r_ctl.rc_inc_enet_oh = 1;
10183 	else
10184 		bbr->r_ctl.rc_inc_enet_oh = 0;
10185 	bbr->r_ctl.rc_probertt_int = bbr_rtt_probe_limit;
10186 	reset_time(&bbr->r_ctl.rc_delrate,
10187 		   bbr_num_pktepo_for_del_limit);
10188 	reset_time_small(&bbr->r_ctl.rc_rttprop,
10189 			 (bbr_filter_len_sec * USECS_IN_SECOND));
10190 	tcp_bbr_tso_size_check(bbr, tcp_get_usecs(&bbr->rc_tv));
10191 }
10192 /*
10193  * Return 0 on success, non-zero on failure
10194  * which indicates the error (usually no memory).
10195  */
10196 static int
10197 bbr_init(struct tcpcb *tp)
10198 {
10199 	struct tcp_bbr *bbr = NULL;
10200 	struct inpcb *inp;
10201 	uint32_t cts;
10202 
10203 	tp->t_fb_ptr = uma_zalloc(bbr_pcb_zone, (M_NOWAIT | M_ZERO));
10204 	if (tp->t_fb_ptr == NULL) {
10205 		/*
10206 		 * We need to allocate memory but cant. The INP and INP_INFO
10207 		 * locks and they are recusive (happens during setup. So a
10208 		 * scheme to drop the locks fails :(
10209 		 *
10210 		 */
10211 		return (ENOMEM);
10212 	}
10213 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
10214 	bbr->rtt_valid = 0;
10215 	inp = tp->t_inpcb;
10216 	inp->inp_flags2 |= INP_CANNOT_DO_ECN;
10217 	inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
10218 	TAILQ_INIT(&bbr->r_ctl.rc_map);
10219 	TAILQ_INIT(&bbr->r_ctl.rc_free);
10220 	TAILQ_INIT(&bbr->r_ctl.rc_tmap);
10221 	bbr->rc_tp = tp;
10222 	if (tp->t_inpcb) {
10223 		bbr->rc_inp = tp->t_inpcb;
10224 	}
10225 	cts = tcp_get_usecs(&bbr->rc_tv);
10226 	tp->t_acktime = 0;
10227 	bbr->rc_allow_data_af_clo = bbr_ignore_data_after_close;
10228 	bbr->r_ctl.rc_reorder_fade = bbr_reorder_fade;
10229 	bbr->rc_tlp_threshold = bbr_tlp_thresh;
10230 	bbr->r_ctl.rc_reorder_shift = bbr_reorder_thresh;
10231 	bbr->r_ctl.rc_pkt_delay = bbr_pkt_delay;
10232 	bbr->r_ctl.rc_min_to = bbr_min_to;
10233 	bbr->rc_bbr_state = BBR_STATE_STARTUP;
10234 	bbr->r_ctl.bbr_lost_at_state = 0;
10235 	bbr->r_ctl.rc_lost_at_startup = 0;
10236 	bbr->rc_all_timers_stopped = 0;
10237 	bbr->r_ctl.rc_bbr_lastbtlbw = 0;
10238 	bbr->r_ctl.rc_pkt_epoch_del = 0;
10239 	bbr->r_ctl.rc_pkt_epoch = 0;
10240 	bbr->r_ctl.rc_lowest_rtt = 0xffffffff;
10241 	bbr->r_ctl.rc_bbr_hptsi_gain = bbr_high_gain;
10242 	bbr->r_ctl.rc_bbr_cwnd_gain = bbr_high_gain;
10243 	bbr->r_ctl.rc_went_idle_time = cts;
10244 	bbr->rc_pacer_started = cts;
10245 	bbr->r_ctl.rc_pkt_epoch_time = cts;
10246 	bbr->r_ctl.rc_rcvtime = cts;
10247 	bbr->r_ctl.rc_bbr_state_time = cts;
10248 	bbr->r_ctl.rc_del_time = cts;
10249 	bbr->r_ctl.rc_tlp_rxt_last_time = cts;
10250 	bbr->r_ctl.last_in_probertt = cts;
10251 	bbr->skip_gain = 0;
10252 	bbr->gain_is_limited = 0;
10253 	bbr->no_pacing_until = bbr_no_pacing_until;
10254 	if (bbr->no_pacing_until)
10255 		bbr->rc_no_pacing = 1;
10256 	if (bbr_use_google_algo) {
10257 		bbr->rc_no_pacing = 0;
10258 		bbr->rc_use_google = 1;
10259 		bbr->r_ctl.bbr_google_discount = bbr_google_discount;
10260 		bbr->r_use_policer = bbr_policer_detection_enabled;
10261 	} else {
10262 		bbr->rc_use_google = 0;
10263 		bbr->r_ctl.bbr_google_discount = 0;
10264 		bbr->r_use_policer = 0;
10265 	}
10266 	if (bbr_ts_limiting)
10267 		bbr->rc_use_ts_limit = 1;
10268 	else
10269 		bbr->rc_use_ts_limit = 0;
10270 	if (bbr_ts_can_raise)
10271 		bbr->ts_can_raise = 1;
10272 	else
10273 		bbr->ts_can_raise = 0;
10274 	if (V_tcp_delack_enabled == 1)
10275 		tp->t_delayed_ack = 2;
10276 	else if (V_tcp_delack_enabled == 0)
10277 		tp->t_delayed_ack = 0;
10278 	else if (V_tcp_delack_enabled < 100)
10279 		tp->t_delayed_ack = V_tcp_delack_enabled;
10280 	else
10281 		tp->t_delayed_ack = 2;
10282 	if (bbr->rc_use_google == 0)
10283 		bbr->r_ctl.rc_probertt_int = bbr_rtt_probe_limit;
10284 	else
10285 		bbr->r_ctl.rc_probertt_int = (USECS_IN_SECOND * 10);
10286 	bbr->r_ctl.rc_min_rto_ms = bbr_rto_min_ms;
10287 	bbr->rc_max_rto_sec = bbr_rto_max_sec;
10288 	bbr->rc_init_win = bbr_def_init_win;
10289 	if (tp->t_flags & TF_REQ_TSTMP)
10290 		bbr->rc_last_options = TCP_TS_OVERHEAD;
10291 	bbr->r_ctl.rc_pace_max_segs = tp->t_maxseg - bbr->rc_last_options;
10292 	bbr->r_ctl.rc_high_rwnd = tp->snd_wnd;
10293 	bbr->r_init_rtt = 1;
10294 
10295 	counter_u64_add(bbr_flows_nohdwr_pacing, 1);
10296 	if (bbr_allow_hdwr_pacing)
10297 		bbr->bbr_hdw_pace_ena = 1;
10298 	else
10299 		bbr->bbr_hdw_pace_ena = 0;
10300 	if (bbr_sends_full_iwnd)
10301 		bbr->bbr_init_win_cheat = 1;
10302 	else
10303 		bbr->bbr_init_win_cheat = 0;
10304 	bbr->r_ctl.bbr_utter_max = bbr_hptsi_utter_max;
10305 	bbr->r_ctl.rc_drain_pg = bbr_drain_gain;
10306 	bbr->r_ctl.rc_startup_pg = bbr_high_gain;
10307 	bbr->rc_loss_exit = bbr_exit_startup_at_loss;
10308 	bbr->r_ctl.bbr_rttprobe_gain_val = bbr_rttprobe_gain;
10309 	bbr->r_ctl.bbr_hptsi_per_second = bbr_hptsi_per_second;
10310 	bbr->r_ctl.bbr_hptsi_segments_delay_tar = bbr_hptsi_segments_delay_tar;
10311 	bbr->r_ctl.bbr_hptsi_segments_max = bbr_hptsi_segments_max;
10312 	bbr->r_ctl.bbr_hptsi_segments_floor = bbr_hptsi_segments_floor;
10313 	bbr->r_ctl.bbr_hptsi_bytes_min = bbr_hptsi_bytes_min;
10314 	bbr->r_ctl.bbr_cross_over = bbr_cross_over;
10315 	bbr->r_ctl.rc_rtt_shrinks = cts;
10316 	if (bbr->rc_use_google) {
10317 		setup_time_filter(&bbr->r_ctl.rc_delrate,
10318 				  FILTER_TYPE_MAX,
10319 				  BBR_NUM_RTTS_FOR_GOOG_DEL_LIMIT);
10320 		setup_time_filter_small(&bbr->r_ctl.rc_rttprop,
10321 					FILTER_TYPE_MIN, (11 * USECS_IN_SECOND));
10322 	} else {
10323 		setup_time_filter(&bbr->r_ctl.rc_delrate,
10324 				  FILTER_TYPE_MAX,
10325 				  bbr_num_pktepo_for_del_limit);
10326 		setup_time_filter_small(&bbr->r_ctl.rc_rttprop,
10327 					FILTER_TYPE_MIN, (bbr_filter_len_sec * USECS_IN_SECOND));
10328 	}
10329 	bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_INIT, 0);
10330 	if (bbr_uses_idle_restart)
10331 		bbr->rc_use_idle_restart = 1;
10332 	else
10333 		bbr->rc_use_idle_restart = 0;
10334 	bbr->r_ctl.rc_bbr_cur_del_rate = 0;
10335 	bbr->r_ctl.rc_initial_hptsi_bw = bbr_initial_bw_bps;
10336 	if (bbr_resends_use_tso)
10337 		bbr->rc_resends_use_tso = 1;
10338 #ifdef NETFLIX_PEAKRATE
10339 	tp->t_peakrate_thr = tp->t_maxpeakrate;
10340 #endif
10341 	if (tp->snd_una != tp->snd_max) {
10342 		/* Create a send map for the current outstanding data */
10343 		struct bbr_sendmap *rsm;
10344 
10345 		rsm = bbr_alloc(bbr);
10346 		if (rsm == NULL) {
10347 			uma_zfree(bbr_pcb_zone, tp->t_fb_ptr);
10348 			tp->t_fb_ptr = NULL;
10349 			return (ENOMEM);
10350 		}
10351 		rsm->r_flags = BBR_OVERMAX;
10352 		rsm->r_tim_lastsent[0] = cts;
10353 		rsm->r_rtr_cnt = 1;
10354 		rsm->r_rtr_bytes = 0;
10355 		rsm->r_start = tp->snd_una;
10356 		rsm->r_end = tp->snd_max;
10357 		rsm->r_dupack = 0;
10358 		rsm->r_delivered = bbr->r_ctl.rc_delivered;
10359 		rsm->r_ts_valid = 0;
10360 		rsm->r_del_ack_ts = tp->ts_recent;
10361 		rsm->r_del_time = cts;
10362 		if (bbr->r_ctl.r_app_limited_until)
10363 			rsm->r_app_limited = 1;
10364 		else
10365 			rsm->r_app_limited = 0;
10366 		TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_map, rsm, r_next);
10367 		TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
10368 		rsm->r_in_tmap = 1;
10369 		if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW)
10370 			rsm->r_bbr_state = bbr_state_val(bbr);
10371 		else
10372 			rsm->r_bbr_state = 8;
10373 	}
10374 	if (bbr_use_rack_resend_cheat && (bbr->rc_use_google == 0))
10375 		bbr->bbr_use_rack_cheat = 1;
10376 	if (bbr_incr_timers && (bbr->rc_use_google == 0))
10377 		bbr->r_ctl.rc_incr_tmrs = 1;
10378 	if (bbr_include_tcp_oh && (bbr->rc_use_google == 0))
10379 		bbr->r_ctl.rc_inc_tcp_oh = 1;
10380 	if (bbr_include_ip_oh && (bbr->rc_use_google == 0))
10381 		bbr->r_ctl.rc_inc_ip_oh = 1;
10382 	if (bbr_include_enet_oh && (bbr->rc_use_google == 0))
10383 		bbr->r_ctl.rc_inc_enet_oh = 1;
10384 
10385 	bbr_log_type_statechange(bbr, cts, __LINE__);
10386 	if (TCPS_HAVEESTABLISHED(tp->t_state) &&
10387 	    (tp->t_srtt)) {
10388 		uint32_t rtt;
10389 
10390 		rtt = (TICKS_2_USEC(tp->t_srtt) >> TCP_RTT_SHIFT);
10391 		apply_filter_min_small(&bbr->r_ctl.rc_rttprop, rtt, cts);
10392 	}
10393 	/* announce the settings and state */
10394 	bbr_log_settings_change(bbr, BBR_RECOVERY_LOWRTT);
10395 	tcp_bbr_tso_size_check(bbr, cts);
10396 	/*
10397 	 * Now call the generic function to start a timer. This will place
10398 	 * the TCB on the hptsi wheel if a timer is needed with appropriate
10399 	 * flags.
10400 	 */
10401 	bbr_stop_all_timers(tp);
10402 	bbr_start_hpts_timer(bbr, tp, cts, 5, 0, 0);
10403 	return (0);
10404 }
10405 
10406 /*
10407  * Return 0 if we can accept the connection. Return
10408  * non-zero if we can't handle the connection. A EAGAIN
10409  * means you need to wait until the connection is up.
10410  * a EADDRNOTAVAIL means we can never handle the connection
10411  * (no SACK).
10412  */
10413 static int
10414 bbr_handoff_ok(struct tcpcb *tp)
10415 {
10416 	if ((tp->t_state == TCPS_CLOSED) ||
10417 	    (tp->t_state == TCPS_LISTEN)) {
10418 		/* Sure no problem though it may not stick */
10419 		return (0);
10420 	}
10421 	if ((tp->t_state == TCPS_SYN_SENT) ||
10422 	    (tp->t_state == TCPS_SYN_RECEIVED)) {
10423 		/*
10424 		 * We really don't know you have to get to ESTAB or beyond
10425 		 * to tell.
10426 		 */
10427 		return (EAGAIN);
10428 	}
10429 	if ((tp->t_flags & TF_SACK_PERMIT) || bbr_sack_not_required) {
10430 		return (0);
10431 	}
10432 	/*
10433 	 * If we reach here we don't do SACK on this connection so we can
10434 	 * never do rack.
10435 	 */
10436 	return (EINVAL);
10437 }
10438 
10439 static void
10440 bbr_fini(struct tcpcb *tp, int32_t tcb_is_purged)
10441 {
10442 	if (tp->t_fb_ptr) {
10443 		uint32_t calc;
10444 		struct tcp_bbr *bbr;
10445 		struct bbr_sendmap *rsm;
10446 
10447 		bbr = (struct tcp_bbr *)tp->t_fb_ptr;
10448 		if (bbr->r_ctl.crte)
10449 			tcp_rel_pacing_rate(bbr->r_ctl.crte, bbr->rc_tp);
10450 		bbr_log_flowend(bbr);
10451 		bbr->rc_tp = NULL;
10452 		if (tp->t_inpcb) {
10453 			/* Backout any flags2 we applied */
10454 			tp->t_inpcb->inp_flags2 &= ~INP_CANNOT_DO_ECN;
10455 			tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
10456 			tp->t_inpcb->inp_flags2 &= ~INP_MBUF_QUEUE_READY;
10457 		}
10458 		if (bbr->bbr_hdrw_pacing)
10459 			counter_u64_add(bbr_flows_whdwr_pacing, -1);
10460 		else
10461 			counter_u64_add(bbr_flows_nohdwr_pacing, -1);
10462 		rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
10463 		while (rsm) {
10464 			TAILQ_REMOVE(&bbr->r_ctl.rc_map, rsm, r_next);
10465 			uma_zfree(bbr_zone, rsm);
10466 			rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
10467 		}
10468 		rsm = TAILQ_FIRST(&bbr->r_ctl.rc_free);
10469 		while (rsm) {
10470 			TAILQ_REMOVE(&bbr->r_ctl.rc_free, rsm, r_next);
10471 			uma_zfree(bbr_zone, rsm);
10472 			rsm = TAILQ_FIRST(&bbr->r_ctl.rc_free);
10473 		}
10474 		calc = bbr->r_ctl.rc_high_rwnd - bbr->r_ctl.rc_init_rwnd;
10475 		if (calc > (bbr->r_ctl.rc_init_rwnd / 10))
10476 			BBR_STAT_INC(bbr_dynamic_rwnd);
10477 		else
10478 			BBR_STAT_INC(bbr_static_rwnd);
10479 		bbr->r_ctl.rc_free_cnt = 0;
10480 		uma_zfree(bbr_pcb_zone, tp->t_fb_ptr);
10481 		tp->t_fb_ptr = NULL;
10482 	}
10483 	/* Make sure snd_nxt is correctly set */
10484 	tp->snd_nxt = tp->snd_max;
10485 }
10486 
10487 static void
10488 bbr_set_state(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t win)
10489 {
10490 	switch (tp->t_state) {
10491 	case TCPS_SYN_SENT:
10492 		bbr->r_state = TCPS_SYN_SENT;
10493 		bbr->r_substate = bbr_do_syn_sent;
10494 		break;
10495 	case TCPS_SYN_RECEIVED:
10496 		bbr->r_state = TCPS_SYN_RECEIVED;
10497 		bbr->r_substate = bbr_do_syn_recv;
10498 		break;
10499 	case TCPS_ESTABLISHED:
10500 		bbr->r_ctl.rc_init_rwnd = max(win, bbr->rc_tp->snd_wnd);
10501 		bbr->r_state = TCPS_ESTABLISHED;
10502 		bbr->r_substate = bbr_do_established;
10503 		break;
10504 	case TCPS_CLOSE_WAIT:
10505 		bbr->r_state = TCPS_CLOSE_WAIT;
10506 		bbr->r_substate = bbr_do_close_wait;
10507 		break;
10508 	case TCPS_FIN_WAIT_1:
10509 		bbr->r_state = TCPS_FIN_WAIT_1;
10510 		bbr->r_substate = bbr_do_fin_wait_1;
10511 		break;
10512 	case TCPS_CLOSING:
10513 		bbr->r_state = TCPS_CLOSING;
10514 		bbr->r_substate = bbr_do_closing;
10515 		break;
10516 	case TCPS_LAST_ACK:
10517 		bbr->r_state = TCPS_LAST_ACK;
10518 		bbr->r_substate = bbr_do_lastack;
10519 		break;
10520 	case TCPS_FIN_WAIT_2:
10521 		bbr->r_state = TCPS_FIN_WAIT_2;
10522 		bbr->r_substate = bbr_do_fin_wait_2;
10523 		break;
10524 	case TCPS_LISTEN:
10525 	case TCPS_CLOSED:
10526 	case TCPS_TIME_WAIT:
10527 	default:
10528 		break;
10529 	};
10530 }
10531 
10532 static void
10533 bbr_substate_change(struct tcp_bbr *bbr, uint32_t cts, int32_t line, int dolog)
10534 {
10535 	/*
10536 	 * Now what state are we going into now? Is there adjustments
10537 	 * needed?
10538 	 */
10539 	int32_t old_state, old_gain;
10540 
10541 
10542 	old_state = bbr_state_val(bbr);
10543 	old_gain = bbr->r_ctl.rc_bbr_hptsi_gain;
10544 	if (bbr_state_val(bbr) == BBR_SUB_LEVEL1) {
10545 		/* Save the lowest srtt we saw in our end of the sub-state */
10546 		bbr->rc_hit_state_1 = 0;
10547 		if (bbr->r_ctl.bbr_smallest_srtt_this_state != 0xffffffff)
10548 			bbr->r_ctl.bbr_smallest_srtt_state2 = bbr->r_ctl.bbr_smallest_srtt_this_state;
10549 	}
10550 	bbr->rc_bbr_substate++;
10551 	if (bbr->rc_bbr_substate >= BBR_SUBSTATE_COUNT) {
10552 		/* Cycle back to first state-> gain */
10553 		bbr->rc_bbr_substate = 0;
10554 	}
10555 	if (bbr_state_val(bbr) == BBR_SUB_GAIN) {
10556 		/*
10557 		 * We enter the gain(5/4) cycle (possibly less if
10558 		 * shallow buffer detection is enabled)
10559 		 */
10560 		if (bbr->skip_gain) {
10561 			/*
10562 			 * Hardware pacing has set our rate to
10563 			 * the max and limited our b/w just
10564 			 * do level i.e. no gain.
10565 			 */
10566 			bbr->r_ctl.rc_bbr_hptsi_gain = bbr_hptsi_gain[BBR_SUB_LEVEL1];
10567 		} else if (bbr->gain_is_limited &&
10568 			   bbr->bbr_hdrw_pacing &&
10569 			   bbr->r_ctl.crte) {
10570 			/*
10571 			 * We can't gain above the hardware pacing
10572 			 * rate which is less than our rate + the gain
10573 			 * calculate the gain needed to reach the hardware
10574 			 * pacing rate..
10575 			 */
10576 			uint64_t bw, rate, gain_calc;
10577 
10578 			bw = bbr_get_bw(bbr);
10579 			rate = bbr->r_ctl.crte->rate;
10580 			if ((rate > bw) &&
10581 			    (((bw *  (uint64_t)bbr_hptsi_gain[BBR_SUB_GAIN]) / (uint64_t)BBR_UNIT) > rate)) {
10582 				gain_calc = (rate * BBR_UNIT) / bw;
10583 				if (gain_calc < BBR_UNIT)
10584 					gain_calc = BBR_UNIT;
10585 				bbr->r_ctl.rc_bbr_hptsi_gain = (uint16_t)gain_calc;
10586 			} else {
10587 				bbr->r_ctl.rc_bbr_hptsi_gain = bbr_hptsi_gain[BBR_SUB_GAIN];
10588 			}
10589 		} else
10590 			bbr->r_ctl.rc_bbr_hptsi_gain = bbr_hptsi_gain[BBR_SUB_GAIN];
10591 		if ((bbr->rc_use_google == 0) && (bbr_gain_to_target == 0)) {
10592 			bbr->r_ctl.rc_bbr_state_atflight = cts;
10593 		} else
10594 			bbr->r_ctl.rc_bbr_state_atflight = 0;
10595 	} else if (bbr_state_val(bbr) == BBR_SUB_DRAIN) {
10596 		bbr->rc_hit_state_1 = 1;
10597 		bbr->r_ctl.rc_exta_time_gd = 0;
10598 		bbr->r_ctl.flightsize_at_drain = ctf_flight_size(bbr->rc_tp,
10599 						     (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
10600 		if (bbr_state_drain_2_tar) {
10601 			bbr->r_ctl.rc_bbr_state_atflight = 0;
10602 		} else
10603 			bbr->r_ctl.rc_bbr_state_atflight = cts;
10604 		bbr->r_ctl.rc_bbr_hptsi_gain = bbr_hptsi_gain[BBR_SUB_DRAIN];
10605 	} else {
10606 		/* All other cycles hit here 2-7 */
10607 		if ((old_state == BBR_SUB_DRAIN) && bbr->rc_hit_state_1) {
10608 			if (bbr_sub_drain_slam_cwnd &&
10609 			    (bbr->rc_use_google == 0) &&
10610 			    (bbr->rc_tp->snd_cwnd < bbr->r_ctl.rc_saved_cwnd)) {
10611 				bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_saved_cwnd;
10612 				bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10613 			}
10614 			if ((cts - bbr->r_ctl.rc_bbr_state_time) > bbr_get_rtt(bbr, BBR_RTT_PROP))
10615 				bbr->r_ctl.rc_exta_time_gd += ((cts - bbr->r_ctl.rc_bbr_state_time) -
10616 							       bbr_get_rtt(bbr, BBR_RTT_PROP));
10617 			else
10618 				bbr->r_ctl.rc_exta_time_gd = 0;
10619 			if (bbr->r_ctl.rc_exta_time_gd) {
10620 				bbr->r_ctl.rc_level_state_extra = bbr->r_ctl.rc_exta_time_gd;
10621 				/* Now chop up the time for each state (div by 7) */
10622 				bbr->r_ctl.rc_level_state_extra /= 7;
10623 				if (bbr_rand_ot && bbr->r_ctl.rc_level_state_extra) {
10624 					/* Add a randomization */
10625 					bbr_randomize_extra_state_time(bbr);
10626 				}
10627 			}
10628 		}
10629 		bbr->r_ctl.rc_bbr_state_atflight = max(1, cts);
10630 		bbr->r_ctl.rc_bbr_hptsi_gain = bbr_hptsi_gain[bbr_state_val(bbr)];
10631 	}
10632 	if (bbr->rc_use_google) {
10633 		bbr->r_ctl.rc_bbr_state_atflight = max(1, cts);
10634 	}
10635 	bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
10636 	bbr->r_ctl.rc_bbr_cwnd_gain = bbr_cwnd_gain;
10637 	if (dolog)
10638 		bbr_log_type_statechange(bbr, cts, line);
10639 
10640 	if (SEQ_GT(cts, bbr->r_ctl.rc_bbr_state_time)) {
10641 		uint32_t time_in;
10642 
10643 		time_in = cts - bbr->r_ctl.rc_bbr_state_time;
10644 		if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW) {
10645 			counter_u64_add(bbr_state_time[(old_state + 5)], time_in);
10646 		} else {
10647 			counter_u64_add(bbr_state_time[bbr->rc_bbr_state], time_in);
10648 		}
10649 	}
10650 	bbr->r_ctl.bbr_smallest_srtt_this_state = 0xffffffff;
10651 	bbr_set_state_target(bbr, __LINE__);
10652 	if (bbr_sub_drain_slam_cwnd &&
10653 	    (bbr->rc_use_google == 0) &&
10654 	    (bbr_state_val(bbr) == BBR_SUB_DRAIN)) {
10655 		/* Slam down the cwnd */
10656 		bbr->r_ctl.rc_saved_cwnd = bbr->rc_tp->snd_cwnd;
10657 		bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_target_at_state;
10658 		if (bbr_sub_drain_app_limit) {
10659 			/* Go app limited if we are on a long drain */
10660 			bbr->r_ctl.r_app_limited_until = (bbr->r_ctl.rc_delivered +
10661 							  ctf_flight_size(bbr->rc_tp,
10662 							      (bbr->r_ctl.rc_sacked +
10663 							       bbr->r_ctl.rc_lost_bytes)));
10664 		}
10665 		bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10666 	}
10667 	if (bbr->rc_lt_use_bw) {
10668 		/* In policed mode we clamp pacing_gain to BBR_UNIT */
10669 		bbr->r_ctl.rc_bbr_hptsi_gain = BBR_UNIT;
10670 	}
10671 	/* Google changes TSO size every cycle */
10672 	if (bbr->rc_use_google)
10673 		tcp_bbr_tso_size_check(bbr, cts);
10674 	bbr->r_ctl.gain_epoch = cts;
10675 	bbr->r_ctl.rc_bbr_state_time = cts;
10676 	bbr->r_ctl.substate_pe = bbr->r_ctl.rc_pkt_epoch;
10677 }
10678 
10679 static void
10680 bbr_set_probebw_google_gains(struct tcp_bbr *bbr, uint32_t cts, uint32_t losses)
10681 {
10682 	if ((bbr_state_val(bbr) == BBR_SUB_DRAIN) &&
10683 	    (google_allow_early_out == 1) &&
10684 	    (bbr->r_ctl.rc_flight_at_input <= bbr->r_ctl.rc_target_at_state)) {
10685 		/* We have reached out target flight size possibly early */
10686 		goto change_state;
10687 	}
10688 	if (TSTMP_LT(cts, bbr->r_ctl.rc_bbr_state_time)) {
10689 		return;
10690 	}
10691 	if ((cts - bbr->r_ctl.rc_bbr_state_time) < bbr_get_rtt(bbr, BBR_RTT_PROP)) {
10692 		/*
10693 		 * Must be a rttProp movement forward before
10694 		 * we can change states.
10695 		 */
10696 		return;
10697 	}
10698 	if (bbr_state_val(bbr) == BBR_SUB_GAIN) {
10699 		/*
10700 		 * The needed time has passed but for
10701 		 * the gain cycle extra rules apply:
10702 		 * 1) If we have seen loss, we exit
10703 		 * 2) If we have not reached the target
10704 		 *    we stay in GAIN (gain-to-target).
10705 		 */
10706 		if (google_consider_lost && losses)
10707 			goto change_state;
10708 		if (bbr->r_ctl.rc_target_at_state > bbr->r_ctl.rc_flight_at_input) {
10709 			return;
10710 		}
10711 	}
10712 change_state:
10713 	/* For gain we must reach our target, all others last 1 rttProp */
10714 	bbr_substate_change(bbr, cts, __LINE__, 1);
10715 }
10716 
10717 static void
10718 bbr_set_probebw_gains(struct tcp_bbr *bbr, uint32_t cts, uint32_t losses)
10719 {
10720 	uint32_t flight, bbr_cur_cycle_time;
10721 
10722 	if (bbr->rc_use_google) {
10723 		bbr_set_probebw_google_gains(bbr, cts, losses);
10724 		return;
10725 	}
10726 	if (cts == 0) {
10727 		/*
10728 		 * Never alow cts to be 0 we
10729 		 * do this so we can judge if
10730 		 * we have set a timestamp.
10731 		 */
10732 		cts = 1;
10733 	}
10734 	if (bbr_state_is_pkt_epoch)
10735 		bbr_cur_cycle_time = bbr_get_rtt(bbr, BBR_RTT_PKTRTT);
10736 	else
10737 		bbr_cur_cycle_time = bbr_get_rtt(bbr, BBR_RTT_PROP);
10738 
10739 	if (bbr->r_ctl.rc_bbr_state_atflight == 0) {
10740 		if (bbr_state_val(bbr) == BBR_SUB_DRAIN) {
10741 			flight = ctf_flight_size(bbr->rc_tp,
10742 				     (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
10743 			if (bbr_sub_drain_slam_cwnd && bbr->rc_hit_state_1) {
10744 				/* Keep it slam down */
10745 				if (bbr->rc_tp->snd_cwnd > bbr->r_ctl.rc_target_at_state) {
10746 					bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_target_at_state;
10747 					bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10748 				}
10749 				if (bbr_sub_drain_app_limit) {
10750 					/* Go app limited if we are on a long drain */
10751 					bbr->r_ctl.r_app_limited_until = (bbr->r_ctl.rc_delivered + flight);
10752 				}
10753 			}
10754 			if (TSTMP_GT(cts, bbr->r_ctl.gain_epoch) &&
10755 			    (((cts - bbr->r_ctl.gain_epoch) > bbr_get_rtt(bbr, BBR_RTT_PROP)) ||
10756 			     (flight >= bbr->r_ctl.flightsize_at_drain))) {
10757 				/*
10758 				 * Still here after the same time as
10759 				 * the gain. We need to drain harder
10760 				 * for the next srtt. Reduce by a set amount
10761 				 * the gain drop is capped at DRAIN states
10762 				 * value (88).
10763 				 */
10764 				bbr->r_ctl.flightsize_at_drain = flight;
10765 				if (bbr_drain_drop_mul &&
10766 				    bbr_drain_drop_div &&
10767 				    (bbr_drain_drop_mul < bbr_drain_drop_div)) {
10768 					/* Use your specific drop value (def 4/5 = 20%) */
10769 					bbr->r_ctl.rc_bbr_hptsi_gain *= bbr_drain_drop_mul;
10770 					bbr->r_ctl.rc_bbr_hptsi_gain /= bbr_drain_drop_div;
10771 				} else {
10772 					/* You get drop of 20% */
10773 					bbr->r_ctl.rc_bbr_hptsi_gain *= 4;
10774 					bbr->r_ctl.rc_bbr_hptsi_gain /= 5;
10775 				}
10776 				if (bbr->r_ctl.rc_bbr_hptsi_gain <= bbr_drain_floor) {
10777 					/* Reduce our gain again to the bottom  */
10778 					bbr->r_ctl.rc_bbr_hptsi_gain = max(bbr_drain_floor, 1);
10779 				}
10780 				bbr_log_exit_gain(bbr, cts, 4);
10781 				/*
10782 				 * Extend out so we wait another
10783 				 * epoch before dropping again.
10784 				 */
10785 				bbr->r_ctl.gain_epoch = cts;
10786 			}
10787 			if (flight <= bbr->r_ctl.rc_target_at_state) {
10788 				if (bbr_sub_drain_slam_cwnd &&
10789 				    (bbr->rc_use_google == 0) &&
10790 				    (bbr->rc_tp->snd_cwnd < bbr->r_ctl.rc_saved_cwnd)) {
10791 					bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_saved_cwnd;
10792 					bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10793 				}
10794 				bbr->r_ctl.rc_bbr_state_atflight = max(cts, 1);
10795 				bbr_log_exit_gain(bbr, cts, 3);
10796 			}
10797 		} else {
10798 			/* Its a gain  */
10799 			if (bbr->r_ctl.rc_lost > bbr->r_ctl.bbr_lost_at_state) {
10800 				bbr->r_ctl.rc_bbr_state_atflight = max(cts, 1);
10801 				goto change_state;
10802 			}
10803 			if ((ctf_outstanding(bbr->rc_tp) >= bbr->r_ctl.rc_target_at_state) ||
10804 			    ((ctf_outstanding(bbr->rc_tp) +  bbr->rc_tp->t_maxseg - 1) >=
10805 			     bbr->rc_tp->snd_wnd)) {
10806 				bbr->r_ctl.rc_bbr_state_atflight = max(cts, 1);
10807 				bbr_log_exit_gain(bbr, cts, 2);
10808 			}
10809 		}
10810 		/**
10811 		 * We fall through and return always one of two things has
10812 		 * occured.
10813 		 * 1) We are still not at target
10814 		 *    <or>
10815 		 * 2) We reached the target and set rc_bbr_state_atflight
10816 		 *    which means we no longer hit this block
10817 		 *    next time we are called.
10818 		 */
10819 		return;
10820 	}
10821 change_state:
10822 	if (TSTMP_LT(cts, bbr->r_ctl.rc_bbr_state_time))
10823 		return;
10824 	if ((cts - bbr->r_ctl.rc_bbr_state_time) < bbr_cur_cycle_time) {
10825 		/* Less than a full time-period has passed */
10826 		return;
10827 	}
10828 	if (bbr->r_ctl.rc_level_state_extra &&
10829 	    (bbr_state_val(bbr) > BBR_SUB_DRAIN) &&
10830 	    ((cts - bbr->r_ctl.rc_bbr_state_time) <
10831 	     (bbr_cur_cycle_time + bbr->r_ctl.rc_level_state_extra))) {
10832 		/* Less than a full time-period + extra has passed */
10833 		return;
10834 	}
10835 	if (bbr_gain_gets_extra_too &&
10836 	    bbr->r_ctl.rc_level_state_extra &&
10837 	    (bbr_state_val(bbr) == BBR_SUB_GAIN) &&
10838 	    ((cts - bbr->r_ctl.rc_bbr_state_time) <
10839 	     (bbr_cur_cycle_time + bbr->r_ctl.rc_level_state_extra))) {
10840 		/* Less than a full time-period + extra has passed */
10841 		return;
10842 	}
10843 	bbr_substate_change(bbr, cts, __LINE__, 1);
10844 }
10845 
10846 static uint32_t
10847 bbr_get_a_state_target(struct tcp_bbr *bbr, uint32_t gain)
10848 {
10849 	uint32_t mss, tar;
10850 
10851 	if (bbr->rc_use_google) {
10852 		/* Google just uses the cwnd target */
10853 		tar = bbr_get_target_cwnd(bbr, bbr_get_bw(bbr), gain);
10854 	} else {
10855 		mss = min((bbr->rc_tp->t_maxseg - bbr->rc_last_options),
10856 			  bbr->r_ctl.rc_pace_max_segs);
10857 		/* Get the base cwnd with gain rounded to a mss */
10858 		tar = roundup(bbr_get_raw_target_cwnd(bbr, bbr_get_bw(bbr),
10859 						      gain), mss);
10860 		/* Make sure it is within our min */
10861 		if (tar < get_min_cwnd(bbr))
10862 			return (get_min_cwnd(bbr));
10863 	}
10864 	return (tar);
10865 }
10866 
10867 static void
10868 bbr_set_state_target(struct tcp_bbr *bbr, int line)
10869 {
10870 	uint32_t tar, meth;
10871 
10872 	if ((bbr->rc_bbr_state == BBR_STATE_PROBE_RTT) &&
10873 	    ((bbr->r_ctl.bbr_rttprobe_gain_val == 0) || bbr->rc_use_google)) {
10874 		/* Special case using old probe-rtt method */
10875 		tar = bbr_rtt_probe_cwndtarg * (bbr->rc_tp->t_maxseg - bbr->rc_last_options);
10876 		meth = 1;
10877 	} else {
10878 		/* Non-probe-rtt case and reduced probe-rtt  */
10879 		if ((bbr->rc_bbr_state == BBR_STATE_PROBE_BW) &&
10880 		    (bbr->r_ctl.rc_bbr_hptsi_gain > BBR_UNIT)) {
10881 			/* For gain cycle we use the hptsi gain */
10882 			tar = bbr_get_a_state_target(bbr, bbr->r_ctl.rc_bbr_hptsi_gain);
10883 			meth = 2;
10884 		} else if ((bbr_target_is_bbunit) || bbr->rc_use_google) {
10885 			/*
10886 			 * If configured, or for google all other states
10887 			 * get BBR_UNIT.
10888 			 */
10889 			tar = bbr_get_a_state_target(bbr, BBR_UNIT);
10890 			meth = 3;
10891 		} else {
10892 			/*
10893 			 * Or we set a target based on the pacing gain
10894 			 * for non-google mode and default (non-configured).
10895 			 * Note we don't set a target goal below drain (192).
10896 			 */
10897 			if (bbr->r_ctl.rc_bbr_hptsi_gain < bbr_hptsi_gain[BBR_SUB_DRAIN])  {
10898 				tar = bbr_get_a_state_target(bbr, bbr_hptsi_gain[BBR_SUB_DRAIN]);
10899 				meth = 4;
10900 			} else {
10901 				tar = bbr_get_a_state_target(bbr, bbr->r_ctl.rc_bbr_hptsi_gain);
10902 				meth = 5;
10903 			}
10904 		}
10905 	}
10906 	bbr_log_set_of_state_target(bbr, tar, line, meth);
10907 	bbr->r_ctl.rc_target_at_state = tar;
10908 }
10909 
10910 static void
10911 bbr_enter_probe_rtt(struct tcp_bbr *bbr, uint32_t cts, int32_t line)
10912 {
10913 	/* Change to probe_rtt */
10914 	uint32_t time_in;
10915 
10916 	bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
10917 	bbr->r_ctl.flightsize_at_drain = ctf_flight_size(bbr->rc_tp,
10918 					     (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
10919 	bbr->r_ctl.r_app_limited_until = (bbr->r_ctl.flightsize_at_drain
10920 					  + bbr->r_ctl.rc_delivered);
10921 	/* Setup so we force feed the filter */
10922 	if (bbr->rc_use_google || bbr_probertt_sets_rtt)
10923 		bbr->rc_prtt_set_ts = 1;
10924 	if (SEQ_GT(cts, bbr->r_ctl.rc_bbr_state_time)) {
10925 		time_in = cts - bbr->r_ctl.rc_bbr_state_time;
10926 		counter_u64_add(bbr_state_time[bbr->rc_bbr_state], time_in);
10927 	}
10928 	bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_ENTERPROBE, 0);
10929 	bbr->r_ctl.rc_rtt_shrinks = cts;
10930 	bbr->r_ctl.last_in_probertt = cts;
10931 	bbr->r_ctl.rc_probertt_srttchktim = cts;
10932 	bbr->r_ctl.rc_bbr_state_time = cts;
10933 	bbr->rc_bbr_state = BBR_STATE_PROBE_RTT;
10934 	/* We need to force the filter to update */
10935 
10936 	if ((bbr_sub_drain_slam_cwnd) &&
10937 	    bbr->rc_hit_state_1 &&
10938 	    (bbr->rc_use_google == 0) &&
10939 	    (bbr_state_val(bbr) == BBR_SUB_DRAIN)) {
10940 		if (bbr->rc_tp->snd_cwnd > bbr->r_ctl.rc_saved_cwnd)
10941 			bbr->r_ctl.rc_saved_cwnd = bbr->rc_tp->snd_cwnd;
10942 	} else
10943 		bbr->r_ctl.rc_saved_cwnd = bbr->rc_tp->snd_cwnd;
10944 	/* Update the lost */
10945 	bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
10946 	if ((bbr->r_ctl.bbr_rttprobe_gain_val == 0) || bbr->rc_use_google){
10947 		/* Set to the non-configurable default of 4 (PROBE_RTT_MIN)  */
10948 		bbr->rc_tp->snd_cwnd = bbr_rtt_probe_cwndtarg * (bbr->rc_tp->t_maxseg - bbr->rc_last_options);
10949 		bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10950 		bbr->r_ctl.rc_bbr_hptsi_gain = BBR_UNIT;
10951 		bbr->r_ctl.rc_bbr_cwnd_gain = BBR_UNIT;
10952 		bbr_log_set_of_state_target(bbr, bbr->rc_tp->snd_cwnd, __LINE__, 6);
10953 		bbr->r_ctl.rc_target_at_state = bbr->rc_tp->snd_cwnd;
10954 	} else {
10955 		/*
10956 		 * We bring it down slowly by using a hptsi gain that is
10957 		 * probably 75%. This will slowly float down our outstanding
10958 		 * without tampering with the cwnd.
10959 		 */
10960 		bbr->r_ctl.rc_bbr_hptsi_gain = bbr->r_ctl.bbr_rttprobe_gain_val;
10961 		bbr->r_ctl.rc_bbr_cwnd_gain = BBR_UNIT;
10962 		bbr_set_state_target(bbr, __LINE__);
10963 		if (bbr_prtt_slam_cwnd &&
10964 		    (bbr->rc_tp->snd_cwnd > bbr->r_ctl.rc_target_at_state)) {
10965 			bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_target_at_state;
10966 			bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10967 		}
10968 	}
10969 	if (ctf_flight_size(bbr->rc_tp,
10970 		(bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes)) <=
10971 	    bbr->r_ctl.rc_target_at_state) {
10972 		/* We are at target */
10973 		bbr->r_ctl.rc_bbr_enters_probertt = cts;
10974 	} else {
10975 		/* We need to come down to reach target before our time begins */
10976 		bbr->r_ctl.rc_bbr_enters_probertt = 0;
10977 	}
10978 	bbr->r_ctl.rc_pe_of_prtt = bbr->r_ctl.rc_pkt_epoch;
10979 	BBR_STAT_INC(bbr_enter_probertt);
10980 	bbr_log_exit_gain(bbr, cts, 0);
10981 	bbr_log_type_statechange(bbr, cts, line);
10982 }
10983 
10984 static void
10985 bbr_check_probe_rtt_limits(struct tcp_bbr *bbr, uint32_t cts)
10986 {
10987 	/*
10988 	 * Sanity check on probe-rtt intervals.
10989 	 * In crazy situations where we are competing
10990 	 * against new-reno flows with huge buffers
10991 	 * our rtt-prop interval could come to dominate
10992 	 * things if we can't get through a full set
10993 	 * of cycles, we need to adjust it.
10994 	 */
10995 	if (bbr_can_adjust_probertt &&
10996 	    (bbr->rc_use_google == 0)) {
10997 		uint16_t val = 0;
10998 		uint32_t cur_rttp, fval, newval, baseval;
10999 
11000 		/* Are we to small and go into probe-rtt to often? */
11001 		baseval = (bbr_get_rtt(bbr, BBR_RTT_PROP) * (BBR_SUBSTATE_COUNT + 1));
11002 		cur_rttp = roundup(baseval, USECS_IN_SECOND);
11003 		fval = bbr_filter_len_sec * USECS_IN_SECOND;
11004 		if (bbr_is_ratio == 0) {
11005 			if (fval > bbr_rtt_probe_limit)
11006 				newval = cur_rttp + (fval - bbr_rtt_probe_limit);
11007 			else
11008 				newval = cur_rttp;
11009 		} else {
11010 			int mul;
11011 
11012 			mul = fval / bbr_rtt_probe_limit;
11013 			newval = cur_rttp * mul;
11014 		}
11015 		if (cur_rttp > 	bbr->r_ctl.rc_probertt_int) {
11016 			bbr->r_ctl.rc_probertt_int = cur_rttp;
11017 			reset_time_small(&bbr->r_ctl.rc_rttprop, newval);
11018 			val = 1;
11019 		} else {
11020 			/*
11021 			 * No adjustments were made
11022 			 * do we need to shrink it?
11023 			 */
11024 			if (bbr->r_ctl.rc_probertt_int > bbr_rtt_probe_limit) {
11025 				if (cur_rttp <= bbr_rtt_probe_limit) {
11026 					/*
11027 					 * Things have calmed down lets
11028 					 * shrink all the way to default
11029 					 */
11030 					bbr->r_ctl.rc_probertt_int = bbr_rtt_probe_limit;
11031 					reset_time_small(&bbr->r_ctl.rc_rttprop,
11032 							 (bbr_filter_len_sec * USECS_IN_SECOND));
11033 					cur_rttp = bbr_rtt_probe_limit;
11034 					newval = (bbr_filter_len_sec * USECS_IN_SECOND);
11035 					val = 2;
11036 				} else {
11037 					/*
11038 					 * Well does some adjustment make sense?
11039 					 */
11040 					if (cur_rttp < bbr->r_ctl.rc_probertt_int) {
11041 						/* We can reduce interval time some */
11042 						bbr->r_ctl.rc_probertt_int = cur_rttp;
11043 						reset_time_small(&bbr->r_ctl.rc_rttprop, newval);
11044 						val = 3;
11045 					}
11046 				}
11047 			}
11048 		}
11049 		if (val)
11050 			bbr_log_rtt_shrinks(bbr, cts, cur_rttp, newval, __LINE__, BBR_RTTS_RESETS_VALUES, val);
11051 	}
11052 }
11053 
11054 static void
11055 bbr_exit_probe_rtt(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
11056 {
11057 	/* Exit probe-rtt */
11058 
11059 	if (tp->snd_cwnd < bbr->r_ctl.rc_saved_cwnd) {
11060 		tp->snd_cwnd = bbr->r_ctl.rc_saved_cwnd;
11061 		bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
11062 	}
11063 	bbr_log_exit_gain(bbr, cts, 1);
11064 	bbr->rc_hit_state_1 = 0;
11065 	bbr->r_ctl.rc_rtt_shrinks = cts;
11066 	bbr->r_ctl.last_in_probertt = cts;
11067 	bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_RTTPROBE, 0);
11068 	bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
11069 	bbr->r_ctl.r_app_limited_until = (ctf_flight_size(tp,
11070 					      (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes)) +
11071 					  bbr->r_ctl.rc_delivered);
11072 	if (SEQ_GT(cts, bbr->r_ctl.rc_bbr_state_time)) {
11073 		uint32_t time_in;
11074 
11075 		time_in = cts - bbr->r_ctl.rc_bbr_state_time;
11076 		counter_u64_add(bbr_state_time[bbr->rc_bbr_state], time_in);
11077 	}
11078 	if (bbr->rc_filled_pipe) {
11079 		/* Switch to probe_bw */
11080 		bbr->rc_bbr_state = BBR_STATE_PROBE_BW;
11081 		bbr->rc_bbr_substate = bbr_pick_probebw_substate(bbr, cts);
11082 		bbr->r_ctl.rc_bbr_cwnd_gain = bbr_cwnd_gain;
11083 		bbr_substate_change(bbr, cts, __LINE__, 0);
11084 		bbr_log_type_statechange(bbr, cts, __LINE__);
11085 	} else {
11086 		/* Back to startup */
11087 		bbr->rc_bbr_state = BBR_STATE_STARTUP;
11088 		bbr->r_ctl.rc_bbr_state_time = cts;
11089 		/*
11090 		 * We don't want to give a complete free 3
11091 		 * measurements until we exit, so we use
11092 		 * the number of pe's we were in probe-rtt
11093 		 * to add to the startup_epoch. That way
11094 		 * we will still retain the old state.
11095 		 */
11096 		bbr->r_ctl.rc_bbr_last_startup_epoch += (bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_pe_of_prtt);
11097 		bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
11098 		/* Make sure to use the lower pg when shifting back in */
11099 		if (bbr->r_ctl.rc_lost &&
11100 		    bbr_use_lower_gain_in_startup &&
11101 		    (bbr->rc_use_google == 0))
11102 			bbr->r_ctl.rc_bbr_hptsi_gain = bbr_startup_lower;
11103 		else
11104 			bbr->r_ctl.rc_bbr_hptsi_gain = bbr->r_ctl.rc_startup_pg;
11105 		bbr->r_ctl.rc_bbr_cwnd_gain = bbr->r_ctl.rc_startup_pg;
11106 		/* Probably not needed but set it anyway */
11107 		bbr_set_state_target(bbr, __LINE__);
11108 		bbr_log_type_statechange(bbr, cts, __LINE__);
11109 		bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11110 		    bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 0);
11111 	}
11112 	bbr_check_probe_rtt_limits(bbr, cts);
11113 }
11114 
11115 static int32_t inline
11116 bbr_should_enter_probe_rtt(struct tcp_bbr *bbr, uint32_t cts)
11117 {
11118 	if ((bbr->rc_past_init_win == 1) &&
11119 	    (bbr->rc_in_persist == 0) &&
11120 	    (bbr_calc_time(cts, bbr->r_ctl.rc_rtt_shrinks) >= bbr->r_ctl.rc_probertt_int)) {
11121 		return (1);
11122 	}
11123 	if (bbr_can_force_probertt &&
11124 	    (bbr->rc_in_persist == 0) &&
11125 	    (TSTMP_GT(cts, bbr->r_ctl.last_in_probertt)) &&
11126 	    ((cts - bbr->r_ctl.last_in_probertt) > bbr->r_ctl.rc_probertt_int)) {
11127 		return (1);
11128 	}
11129 	return (0);
11130 }
11131 
11132 
11133 static int32_t
11134 bbr_google_startup(struct tcp_bbr *bbr, uint32_t cts, int32_t  pkt_epoch)
11135 {
11136 	uint64_t btlbw, gain;
11137 	if (pkt_epoch == 0) {
11138 		/*
11139 		 * Need to be on a pkt-epoch to continue.
11140 		 */
11141 		return (0);
11142 	}
11143 	btlbw = bbr_get_full_bw(bbr);
11144 	gain = ((bbr->r_ctl.rc_bbr_lastbtlbw *
11145 		 (uint64_t)bbr_start_exit) / (uint64_t)100) + bbr->r_ctl.rc_bbr_lastbtlbw;
11146 	if (btlbw >= gain) {
11147 		bbr->r_ctl.rc_bbr_last_startup_epoch = bbr->r_ctl.rc_pkt_epoch;
11148 		bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11149 				      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 3);
11150 		bbr->r_ctl.rc_bbr_lastbtlbw = btlbw;
11151 	}
11152 	if ((bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_bbr_last_startup_epoch) >= BBR_STARTUP_EPOCHS)
11153 		return (1);
11154 	bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11155 			      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 8);
11156 	return(0);
11157 }
11158 
11159 static int32_t inline
11160 bbr_state_startup(struct tcp_bbr *bbr, uint32_t cts, int32_t epoch, int32_t pkt_epoch)
11161 {
11162 	/* Have we gained 25% in the last 3 packet based epoch's? */
11163 	uint64_t btlbw, gain;
11164 	int do_exit;
11165 	int delta, rtt_gain;
11166 
11167 	if ((bbr->rc_tp->snd_una == bbr->rc_tp->snd_max) &&
11168 	    (bbr_calc_time(cts, bbr->r_ctl.rc_went_idle_time) >= bbr_rtt_probe_time)) {
11169 		/*
11170 		 * This qualifies as a RTT_PROBE session since we drop the
11171 		 * data outstanding to nothing and waited more than
11172 		 * bbr_rtt_probe_time.
11173 		 */
11174 		bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_WASIDLE, 0);
11175 		bbr_set_reduced_rtt(bbr, cts, __LINE__);
11176 	}
11177 	if (bbr_should_enter_probe_rtt(bbr, cts)) {
11178 		bbr_enter_probe_rtt(bbr, cts, __LINE__);
11179 		return (0);
11180 	}
11181 	if (bbr->rc_use_google)
11182 		return (bbr_google_startup(bbr, cts,  pkt_epoch));
11183 
11184 	if ((bbr->r_ctl.rc_lost > bbr->r_ctl.rc_lost_at_startup) &&
11185 	    (bbr_use_lower_gain_in_startup)) {
11186 		/* Drop to a lower gain 1.5 x since we saw loss */
11187 		bbr->r_ctl.rc_bbr_hptsi_gain = bbr_startup_lower;
11188 	}
11189 	if (pkt_epoch == 0) {
11190 		/*
11191 		 * Need to be on a pkt-epoch to continue.
11192 		 */
11193 		return (0);
11194 	}
11195 	if (bbr_rtt_gain_thresh) {
11196 		/*
11197 		 * Do we allow a flow to stay
11198 		 * in startup with no loss and no
11199 		 * gain in rtt over a set threshold?
11200 		 */
11201 		if (bbr->r_ctl.rc_pkt_epoch_rtt &&
11202 		    bbr->r_ctl.startup_last_srtt &&
11203 		    (bbr->r_ctl.rc_pkt_epoch_rtt > bbr->r_ctl.startup_last_srtt)) {
11204 			delta = bbr->r_ctl.rc_pkt_epoch_rtt - bbr->r_ctl.startup_last_srtt;
11205 			rtt_gain = (delta * 100) / bbr->r_ctl.startup_last_srtt;
11206 		} else
11207 			rtt_gain = 0;
11208 		if ((bbr->r_ctl.startup_last_srtt == 0)  ||
11209 		    (bbr->r_ctl.rc_pkt_epoch_rtt < bbr->r_ctl.startup_last_srtt))
11210 			/* First time or new lower value */
11211 			bbr->r_ctl.startup_last_srtt = bbr->r_ctl.rc_pkt_epoch_rtt;
11212 
11213 		if ((bbr->r_ctl.rc_lost == 0) &&
11214 		    (rtt_gain < bbr_rtt_gain_thresh)) {
11215 			/*
11216 			 * No loss, and we are under
11217 			 * our gain threhold for
11218 			 * increasing RTT.
11219 			 */
11220 			if (bbr->r_ctl.rc_bbr_last_startup_epoch < bbr->r_ctl.rc_pkt_epoch)
11221 				bbr->r_ctl.rc_bbr_last_startup_epoch++;
11222 			bbr_log_startup_event(bbr, cts, rtt_gain,
11223 					      delta, bbr->r_ctl.startup_last_srtt, 10);
11224 			return (0);
11225 		}
11226 	}
11227 	if ((bbr->r_ctl.r_measurement_count == bbr->r_ctl.last_startup_measure) &&
11228 	    (bbr->r_ctl.rc_lost_at_startup == bbr->r_ctl.rc_lost) &&
11229 	    (!IN_RECOVERY(bbr->rc_tp->t_flags))) {
11230 		/*
11231 		 * We only assess if we have a new measurment when
11232 		 * we have no loss and are not in recovery.
11233 		 * Drag up by one our last_startup epoch so we will hold
11234 		 * the number of non-gain we have already accumulated.
11235 		 */
11236 		if (bbr->r_ctl.rc_bbr_last_startup_epoch < bbr->r_ctl.rc_pkt_epoch)
11237 			bbr->r_ctl.rc_bbr_last_startup_epoch++;
11238 		bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11239 				      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 9);
11240 		return (0);
11241 	}
11242 	/* Case where we reduced the lost (bad retransmit) */
11243 	if (bbr->r_ctl.rc_lost_at_startup > bbr->r_ctl.rc_lost)
11244 		bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
11245 	bbr->r_ctl.last_startup_measure = bbr->r_ctl.r_measurement_count;
11246 	btlbw = bbr_get_full_bw(bbr);
11247 	if (bbr->r_ctl.rc_bbr_hptsi_gain == bbr_startup_lower)
11248 		gain = ((bbr->r_ctl.rc_bbr_lastbtlbw *
11249 			 (uint64_t)bbr_low_start_exit) / (uint64_t)100) + bbr->r_ctl.rc_bbr_lastbtlbw;
11250 	else
11251 		gain = ((bbr->r_ctl.rc_bbr_lastbtlbw *
11252 			 (uint64_t)bbr_start_exit) / (uint64_t)100) + bbr->r_ctl.rc_bbr_lastbtlbw;
11253 	do_exit = 0;
11254 	if (btlbw > bbr->r_ctl.rc_bbr_lastbtlbw)
11255 		bbr->r_ctl.rc_bbr_lastbtlbw = btlbw;
11256 	if (btlbw >= gain) {
11257 		bbr->r_ctl.rc_bbr_last_startup_epoch = bbr->r_ctl.rc_pkt_epoch;
11258 		/* Update the lost so we won't exit in next set of tests */
11259 		bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
11260 		bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11261 				      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 3);
11262 	}
11263 	if ((bbr->rc_loss_exit &&
11264 	     (bbr->r_ctl.rc_lost > bbr->r_ctl.rc_lost_at_startup) &&
11265 	     (bbr->r_ctl.rc_pkt_epoch_loss_rate > bbr_startup_loss_thresh)) &&
11266 	    ((bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_bbr_last_startup_epoch) >= BBR_STARTUP_EPOCHS)) {
11267 		/*
11268 		 * If we had no gain,  we had loss and that loss was above
11269 		 * our threshould, the rwnd is not constrained, and we have
11270 		 * had at least 3 packet epochs exit. Note that this is
11271 		 * switched off by sysctl. Google does not do this by the
11272 		 * way.
11273 		 */
11274 		if ((ctf_flight_size(bbr->rc_tp,
11275 			 (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes)) +
11276 		     (2 * max(bbr->r_ctl.rc_pace_max_segs, bbr->rc_tp->t_maxseg))) <= bbr->rc_tp->snd_wnd) {
11277 			do_exit = 1;
11278 			bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11279 					      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 4);
11280 		} else {
11281 			/* Just record an updated loss value */
11282 			bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
11283 			bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11284 					      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 5);
11285 		}
11286 	} else
11287 		bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
11288 	if (((bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_bbr_last_startup_epoch) >= BBR_STARTUP_EPOCHS) ||
11289 	    do_exit) {
11290 		/* Return 1 to exit the startup state. */
11291 		return (1);
11292 	}
11293 	/* Stay in startup */
11294 	bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11295 			      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 8);
11296 	return (0);
11297 }
11298 
11299 static void
11300 bbr_state_change(struct tcp_bbr *bbr, uint32_t cts, int32_t epoch, int32_t pkt_epoch, uint32_t losses)
11301 {
11302 	/*
11303 	 * A tick occured in the rtt epoch do we need to do anything?
11304 	 */
11305 #ifdef BBR_INVARIANTS
11306 	if ((bbr->rc_bbr_state != BBR_STATE_STARTUP) &&
11307 	    (bbr->rc_bbr_state != BBR_STATE_DRAIN) &&
11308 	    (bbr->rc_bbr_state != BBR_STATE_PROBE_RTT) &&
11309 	    (bbr->rc_bbr_state != BBR_STATE_IDLE_EXIT) &&
11310 	    (bbr->rc_bbr_state != BBR_STATE_PROBE_BW)) {
11311 		/* Debug code? */
11312 		panic("Unknown BBR state %d?\n", bbr->rc_bbr_state);
11313 	}
11314 #endif
11315 	if (bbr->rc_bbr_state == BBR_STATE_STARTUP) {
11316 		/* Do we exit the startup state? */
11317 		if (bbr_state_startup(bbr, cts, epoch, pkt_epoch)) {
11318 			uint32_t time_in;
11319 
11320 			bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11321 					      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 6);
11322 			bbr->rc_filled_pipe = 1;
11323 			bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
11324 			if (SEQ_GT(cts, bbr->r_ctl.rc_bbr_state_time)) {
11325 
11326 				time_in = cts - bbr->r_ctl.rc_bbr_state_time;
11327 				counter_u64_add(bbr_state_time[bbr->rc_bbr_state], time_in);
11328 			} else
11329 				time_in = 0;
11330 			if (bbr->rc_no_pacing)
11331 				bbr->rc_no_pacing = 0;
11332 			bbr->r_ctl.rc_bbr_state_time = cts;
11333 			bbr->r_ctl.rc_bbr_hptsi_gain = bbr->r_ctl.rc_drain_pg;
11334 			bbr->rc_bbr_state = BBR_STATE_DRAIN;
11335 			bbr_set_state_target(bbr, __LINE__);
11336 			if ((bbr->rc_use_google == 0) &&
11337 			    bbr_slam_cwnd_in_main_drain) {
11338 				/* Here we don't have to worry about probe-rtt */
11339 				bbr->r_ctl.rc_saved_cwnd = bbr->rc_tp->snd_cwnd;
11340 				bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_target_at_state;
11341 				bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
11342 			}
11343 			bbr->r_ctl.rc_bbr_cwnd_gain = bbr_high_gain;
11344 			bbr_log_type_statechange(bbr, cts, __LINE__);
11345 			if (ctf_flight_size(bbr->rc_tp,
11346 			        (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes)) <=
11347 			    bbr->r_ctl.rc_target_at_state) {
11348 				/*
11349 				 * Switch to probe_bw if we are already
11350 				 * there
11351 				 */
11352 				bbr->rc_bbr_substate = bbr_pick_probebw_substate(bbr, cts);
11353 				bbr_substate_change(bbr, cts, __LINE__, 0);
11354 				bbr->rc_bbr_state = BBR_STATE_PROBE_BW;
11355 				bbr_log_type_statechange(bbr, cts, __LINE__);
11356 			}
11357 		}
11358 	} else if (bbr->rc_bbr_state == BBR_STATE_IDLE_EXIT) {
11359 		uint32_t inflight;
11360 		struct tcpcb *tp;
11361 
11362 		tp = bbr->rc_tp;
11363 		inflight = ctf_flight_size(tp,
11364 			      (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
11365 		if (inflight >= bbr->r_ctl.rc_target_at_state) {
11366 			/* We have reached a flight of the cwnd target */
11367 			bbr->rc_bbr_state = BBR_STATE_PROBE_BW;
11368 			bbr->r_ctl.rc_bbr_hptsi_gain = BBR_UNIT;
11369 			bbr->r_ctl.rc_bbr_cwnd_gain = BBR_UNIT;
11370 			bbr_set_state_target(bbr, __LINE__);
11371 			/*
11372 			 * Rig it so we don't do anything crazy and
11373 			 * start fresh with a new randomization.
11374 			 */
11375 			bbr->r_ctl.bbr_smallest_srtt_this_state = 0xffffffff;
11376 			bbr->rc_bbr_substate = BBR_SUB_LEVEL6;
11377 			bbr_substate_change(bbr, cts, __LINE__, 1);
11378 		}
11379 	} else if (bbr->rc_bbr_state == BBR_STATE_DRAIN) {
11380 		/* Has in-flight reached the bdp (or less)? */
11381 		uint32_t inflight;
11382 		struct tcpcb *tp;
11383 
11384 		tp = bbr->rc_tp;
11385 		inflight = ctf_flight_size(tp,
11386 			      (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
11387 		if ((bbr->rc_use_google == 0) &&
11388 		    bbr_slam_cwnd_in_main_drain &&
11389 		    (bbr->rc_tp->snd_cwnd > bbr->r_ctl.rc_target_at_state)) {
11390 			/*
11391 			 * Here we don't have to worry about probe-rtt
11392 			 * re-slam it, but keep it slammed down.
11393 			 */
11394 			bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_target_at_state;
11395 			bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
11396 		}
11397 		if (inflight <= bbr->r_ctl.rc_target_at_state) {
11398 			/* We have drained */
11399 			bbr->rc_bbr_state = BBR_STATE_PROBE_BW;
11400 			bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
11401 			if (SEQ_GT(cts, bbr->r_ctl.rc_bbr_state_time)) {
11402 				uint32_t time_in;
11403 
11404 				time_in = cts - bbr->r_ctl.rc_bbr_state_time;
11405 				counter_u64_add(bbr_state_time[bbr->rc_bbr_state], time_in);
11406 			}
11407 			if ((bbr->rc_use_google == 0) &&
11408 			    bbr_slam_cwnd_in_main_drain &&
11409 			    (tp->snd_cwnd < bbr->r_ctl.rc_saved_cwnd)) {
11410 				/* Restore the cwnd */
11411 				tp->snd_cwnd = bbr->r_ctl.rc_saved_cwnd;
11412 				bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
11413 			}
11414 			/* Setup probe-rtt has being done now RRS-HERE */
11415 			bbr->r_ctl.rc_rtt_shrinks = cts;
11416 			bbr->r_ctl.last_in_probertt = cts;
11417 			bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_LEAVE_DRAIN, 0);
11418 			/* Randomly pick a sub-state */
11419 			bbr->rc_bbr_substate = bbr_pick_probebw_substate(bbr, cts);
11420 			bbr_substate_change(bbr, cts, __LINE__, 0);
11421 			bbr_log_type_statechange(bbr, cts, __LINE__);
11422 		}
11423 	} else if (bbr->rc_bbr_state == BBR_STATE_PROBE_RTT) {
11424 		uint32_t flight;
11425 
11426 		flight = ctf_flight_size(bbr->rc_tp,
11427 			     (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
11428 		bbr->r_ctl.r_app_limited_until = (flight + bbr->r_ctl.rc_delivered);
11429 		if (((bbr->r_ctl.bbr_rttprobe_gain_val == 0) || bbr->rc_use_google) &&
11430 		    (bbr->rc_tp->snd_cwnd > bbr->r_ctl.rc_target_at_state)) {
11431 			/*
11432 			 * We must keep cwnd at the desired MSS.
11433 			 */
11434 			bbr->rc_tp->snd_cwnd = bbr_rtt_probe_cwndtarg * (bbr->rc_tp->t_maxseg - bbr->rc_last_options);
11435 			bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
11436 		} else if ((bbr_prtt_slam_cwnd) &&
11437 			   (bbr->rc_tp->snd_cwnd > bbr->r_ctl.rc_target_at_state)) {
11438 			/* Re-slam it */
11439 			bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_target_at_state;
11440 			bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
11441 		}
11442 		if (bbr->r_ctl.rc_bbr_enters_probertt == 0) {
11443 			/* Has outstanding reached our target? */
11444 			if (flight <= bbr->r_ctl.rc_target_at_state) {
11445 				bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_REACHTAR, 0);
11446 				bbr->r_ctl.rc_bbr_enters_probertt = cts;
11447 				/* If time is exactly 0, be 1usec off */
11448 				if (bbr->r_ctl.rc_bbr_enters_probertt == 0)
11449 					bbr->r_ctl.rc_bbr_enters_probertt = 1;
11450 				if (bbr->rc_use_google == 0) {
11451 					/*
11452 					 * Restore any lowering that as occured to
11453 					 * reach here
11454 					 */
11455 					if (bbr->r_ctl.bbr_rttprobe_gain_val)
11456 						bbr->r_ctl.rc_bbr_hptsi_gain = bbr->r_ctl.bbr_rttprobe_gain_val;
11457 					else
11458 						bbr->r_ctl.rc_bbr_hptsi_gain = BBR_UNIT;
11459 				}
11460 			}
11461 			if ((bbr->r_ctl.rc_bbr_enters_probertt == 0) &&
11462 			    (bbr->rc_use_google == 0) &&
11463 			    bbr->r_ctl.bbr_rttprobe_gain_val &&
11464 			    (((cts - bbr->r_ctl.rc_probertt_srttchktim) > bbr_get_rtt(bbr, bbr_drain_rtt)) ||
11465 			     (flight >= bbr->r_ctl.flightsize_at_drain))) {
11466 				/*
11467 				 * We have doddled with our current hptsi
11468 				 * gain an srtt and have still not made it
11469 				 * to target, or we have increased our flight.
11470 				 * Lets reduce the gain by xx%
11471 				 * flooring the reduce at DRAIN (based on
11472 				 * mul/div)
11473 				 */
11474 				int red;
11475 
11476 				bbr->r_ctl.flightsize_at_drain = flight;
11477 				bbr->r_ctl.rc_probertt_srttchktim = cts;
11478 				red = max((bbr->r_ctl.bbr_rttprobe_gain_val / 10), 1);
11479 				if ((bbr->r_ctl.rc_bbr_hptsi_gain - red) > max(bbr_drain_floor, 1)) {
11480 					/* Reduce our gain again */
11481 					bbr->r_ctl.rc_bbr_hptsi_gain -= red;
11482 					bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_SHRINK_PG, 0);
11483 				} else if (bbr->r_ctl.rc_bbr_hptsi_gain > max(bbr_drain_floor, 1)) {
11484 					/* one more chance before we give up */
11485 					bbr->r_ctl.rc_bbr_hptsi_gain = max(bbr_drain_floor, 1);
11486 					bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_SHRINK_PG_FINAL, 0);
11487 				} else {
11488 					/* At the very bottom */
11489 					bbr->r_ctl.rc_bbr_hptsi_gain = max((bbr_drain_floor-1), 1);
11490 				}
11491 			}
11492 		}
11493 		if (bbr->r_ctl.rc_bbr_enters_probertt &&
11494 		    (TSTMP_GT(cts, bbr->r_ctl.rc_bbr_enters_probertt)) &&
11495 		    ((cts - bbr->r_ctl.rc_bbr_enters_probertt) >= bbr_rtt_probe_time)) {
11496 			/* Time to exit probe RTT normally */
11497 			bbr_exit_probe_rtt(bbr->rc_tp, bbr, cts);
11498 		}
11499 	} else if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW) {
11500 		if ((bbr->rc_tp->snd_una == bbr->rc_tp->snd_max) &&
11501 		    (bbr_calc_time(cts, bbr->r_ctl.rc_went_idle_time) >= bbr_rtt_probe_time)) {
11502 			/*
11503 			 * This qualifies as a RTT_PROBE session since we
11504 			 * drop the data outstanding to nothing and waited
11505 			 * more than bbr_rtt_probe_time.
11506 			 */
11507 			bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_WASIDLE, 0);
11508 			bbr_set_reduced_rtt(bbr, cts, __LINE__);
11509 		}
11510 		if (bbr_should_enter_probe_rtt(bbr, cts)) {
11511 			bbr_enter_probe_rtt(bbr, cts, __LINE__);
11512 		} else {
11513 			bbr_set_probebw_gains(bbr, cts, losses);
11514 		}
11515 	}
11516 }
11517 
11518 static void
11519 bbr_check_bbr_for_state(struct tcp_bbr *bbr, uint32_t cts, int32_t line, uint32_t losses)
11520 {
11521 	int32_t epoch = 0;
11522 
11523 	if ((cts - bbr->r_ctl.rc_rcv_epoch_start) >= bbr_get_rtt(bbr, BBR_RTT_PROP)) {
11524 		bbr_set_epoch(bbr, cts, line);
11525 		/* At each epoch doe lt bw sampling */
11526 		epoch = 1;
11527 	}
11528 	bbr_state_change(bbr, cts, epoch, bbr->rc_is_pkt_epoch_now, losses);
11529 }
11530 
11531 static int
11532 bbr_do_segment_nounlock(struct mbuf *m, struct tcphdr *th, struct socket *so,
11533     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos,
11534     int32_t nxt_pkt, struct timeval *tv)
11535 {
11536 	int32_t thflags, retval;
11537 	uint32_t cts, lcts;
11538 	uint32_t tiwin;
11539 	struct tcpopt to;
11540 	struct tcp_bbr *bbr;
11541 	struct bbr_sendmap *rsm;
11542 	struct timeval ltv;
11543 	int32_t did_out = 0;
11544 	int32_t in_recovery;
11545 	uint16_t nsegs;
11546 	int32_t prev_state;
11547 	uint32_t lost;
11548 
11549 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
11550 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
11551 	/* add in our stats */
11552 	kern_prefetch(bbr, &prev_state);
11553 	prev_state = 0;
11554 	thflags = th->th_flags;
11555 	/*
11556 	 * If this is either a state-changing packet or current state isn't
11557 	 * established, we require a write lock on tcbinfo.  Otherwise, we
11558 	 * allow the tcbinfo to be in either alocked or unlocked, as the
11559 	 * caller may have unnecessarily acquired a write lock due to a
11560 	 * race.
11561 	 */
11562 	INP_WLOCK_ASSERT(tp->t_inpcb);
11563 	KASSERT(tp->t_state > TCPS_LISTEN, ("%s: TCPS_LISTEN",
11564 	    __func__));
11565 	KASSERT(tp->t_state != TCPS_TIME_WAIT, ("%s: TCPS_TIME_WAIT",
11566 	    __func__));
11567 
11568 	tp->t_rcvtime = ticks;
11569 	/*
11570 	 * Unscale the window into a 32-bit value. For the SYN_SENT state
11571 	 * the scale is zero.
11572 	 */
11573 	tiwin = th->th_win << tp->snd_scale;
11574 #ifdef STATS
11575 	stats_voi_update_abs_ulong(tp->t_stats, VOI_TCP_FRWIN, tiwin);
11576 #endif
11577 	/*
11578 	 * Parse options on any incoming segment.
11579 	 */
11580 	tcp_dooptions(&to, (u_char *)(th + 1),
11581 	    (th->th_off << 2) - sizeof(struct tcphdr),
11582 	    (thflags & TH_SYN) ? TO_SYN : 0);
11583 
11584 	if (m->m_flags & M_TSTMP) {
11585 		/* Prefer the hardware timestamp if present */
11586 		struct timespec ts;
11587 
11588 		mbuf_tstmp2timespec(m, &ts);
11589 		bbr->rc_tv.tv_sec = ts.tv_sec;
11590 		bbr->rc_tv.tv_usec = ts.tv_nsec / 1000;
11591 		bbr->r_ctl.rc_rcvtime = cts = tcp_tv_to_usectick(&bbr->rc_tv);
11592 	} else if (m->m_flags & M_TSTMP_LRO) {
11593 		/* Next the arrival timestamp */
11594 		struct timespec ts;
11595 
11596 		mbuf_tstmp2timespec(m, &ts);
11597 		bbr->rc_tv.tv_sec = ts.tv_sec;
11598 		bbr->rc_tv.tv_usec = ts.tv_nsec / 1000;
11599 		bbr->r_ctl.rc_rcvtime = cts = tcp_tv_to_usectick(&bbr->rc_tv);
11600 	} else {
11601 		/*
11602 		 * Ok just get the current time.
11603 		 */
11604 		bbr->r_ctl.rc_rcvtime = lcts = cts = tcp_get_usecs(&bbr->rc_tv);
11605 	}
11606 	/*
11607 	 * If echoed timestamp is later than the current time, fall back to
11608 	 * non RFC1323 RTT calculation.  Normalize timestamp if syncookies
11609 	 * were used when this connection was established.
11610 	 */
11611 	if ((to.to_flags & TOF_TS) && (to.to_tsecr != 0)) {
11612 		to.to_tsecr -= tp->ts_offset;
11613 		if (TSTMP_GT(to.to_tsecr, tcp_tv_to_mssectick(&bbr->rc_tv)))
11614 			to.to_tsecr = 0;
11615 	}
11616 	/*
11617 	 * If its the first time in we need to take care of options and
11618 	 * verify we can do SACK for rack!
11619 	 */
11620 	if (bbr->r_state == 0) {
11621 		/*
11622 		 * Process options only when we get SYN/ACK back. The SYN
11623 		 * case for incoming connections is handled in tcp_syncache.
11624 		 * According to RFC1323 the window field in a SYN (i.e., a
11625 		 * <SYN> or <SYN,ACK>) segment itself is never scaled. XXX
11626 		 * this is traditional behavior, may need to be cleaned up.
11627 		 */
11628 		if (bbr->rc_inp == NULL) {
11629 			bbr->rc_inp = tp->t_inpcb;
11630 		}
11631 		/*
11632 		 * We need to init rc_inp here since its not init'd when
11633 		 * bbr_init is called
11634 		 */
11635 		if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) {
11636 			if ((to.to_flags & TOF_SCALE) &&
11637 			    (tp->t_flags & TF_REQ_SCALE)) {
11638 				tp->t_flags |= TF_RCVD_SCALE;
11639 				tp->snd_scale = to.to_wscale;
11640 			}
11641 			/*
11642 			 * Initial send window.  It will be updated with the
11643 			 * next incoming segment to the scaled value.
11644 			 */
11645 			tp->snd_wnd = th->th_win;
11646 			if (to.to_flags & TOF_TS) {
11647 				tp->t_flags |= TF_RCVD_TSTMP;
11648 				tp->ts_recent = to.to_tsval;
11649 				tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
11650 			}
11651 			if (to.to_flags & TOF_MSS)
11652 				tcp_mss(tp, to.to_mss);
11653 			if ((tp->t_flags & TF_SACK_PERMIT) &&
11654 			    (to.to_flags & TOF_SACKPERM) == 0)
11655 				tp->t_flags &= ~TF_SACK_PERMIT;
11656 			if (IS_FASTOPEN(tp->t_flags)) {
11657 				if (to.to_flags & TOF_FASTOPEN) {
11658 					uint16_t mss;
11659 
11660 					if (to.to_flags & TOF_MSS)
11661 						mss = to.to_mss;
11662 					else
11663 						if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
11664 							mss = TCP6_MSS;
11665 						else
11666 							mss = TCP_MSS;
11667 					tcp_fastopen_update_cache(tp, mss,
11668 					    to.to_tfo_len, to.to_tfo_cookie);
11669 				} else
11670 					tcp_fastopen_disable_path(tp);
11671 			}
11672 		}
11673 		/*
11674 		 * At this point we are at the initial call. Here we decide
11675 		 * if we are doing RACK or not. We do this by seeing if
11676 		 * TF_SACK_PERMIT is set, if not rack is *not* possible and
11677 		 * we switch to the default code.
11678 		 */
11679 		if ((tp->t_flags & TF_SACK_PERMIT) == 0) {
11680 			/* Bail */
11681 			tcp_switch_back_to_default(tp);
11682 			(*tp->t_fb->tfb_tcp_do_segment) (m, th, so, tp, drop_hdrlen,
11683 			    tlen, iptos);
11684 			return (1);
11685 		}
11686 		/* Set the flag */
11687 		bbr->r_is_v6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0;
11688 		tcp_set_hpts(tp->t_inpcb);
11689 		sack_filter_clear(&bbr->r_ctl.bbr_sf, th->th_ack);
11690 	}
11691 	if (thflags & TH_ACK) {
11692 		/* Track ack types */
11693 		if (to.to_flags & TOF_SACK)
11694 			BBR_STAT_INC(bbr_acks_with_sacks);
11695 		else
11696 			BBR_STAT_INC(bbr_plain_acks);
11697 	}
11698 	/*
11699 	 * This is the one exception case where we set the rack state
11700 	 * always. All other times (timers etc) we must have a rack-state
11701 	 * set (so we assure we have done the checks above for SACK).
11702 	 */
11703 	if (bbr->r_state != tp->t_state)
11704 		bbr_set_state(tp, bbr, tiwin);
11705 
11706 	if (SEQ_GT(th->th_ack, tp->snd_una) && (rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map)) != NULL)
11707 		kern_prefetch(rsm, &prev_state);
11708 	prev_state = bbr->r_state;
11709 	bbr->rc_ack_was_delayed = 0;
11710 	lost = bbr->r_ctl.rc_lost;
11711 	bbr->rc_is_pkt_epoch_now = 0;
11712 	if (m->m_flags & (M_TSTMP|M_TSTMP_LRO)) {
11713 		/* Get the real time into lcts and figure the real delay */
11714 		lcts = tcp_get_usecs(&ltv);
11715 		if (TSTMP_GT(lcts, cts)) {
11716 			bbr->r_ctl.rc_ack_hdwr_delay = lcts - cts;
11717 			bbr->rc_ack_was_delayed = 1;
11718 			if (TSTMP_GT(bbr->r_ctl.rc_ack_hdwr_delay,
11719 				     bbr->r_ctl.highest_hdwr_delay))
11720 				bbr->r_ctl.highest_hdwr_delay = bbr->r_ctl.rc_ack_hdwr_delay;
11721 		} else {
11722 			bbr->r_ctl.rc_ack_hdwr_delay = 0;
11723 			bbr->rc_ack_was_delayed = 0;
11724 		}
11725 	} else {
11726 		bbr->r_ctl.rc_ack_hdwr_delay = 0;
11727 		bbr->rc_ack_was_delayed = 0;
11728 	}
11729 	bbr_log_ack_event(bbr, th, &to, tlen, nsegs, cts, nxt_pkt, m);
11730 	if ((thflags & TH_SYN) && (thflags & TH_FIN) && V_drop_synfin) {
11731 		retval = 0;
11732 		m_freem(m);
11733                 goto done_with_input;
11734         }
11735         /*
11736          * If a segment with the ACK-bit set arrives in the SYN-SENT state
11737          * check SEQ.ACK first as described on page 66 of RFC 793, section 3.9.
11738          */
11739         if ((tp->t_state == TCPS_SYN_SENT) && (thflags & TH_ACK) &&
11740             (SEQ_LEQ(th->th_ack, tp->iss) || SEQ_GT(th->th_ack, tp->snd_max))) {
11741 		ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11742                 return (1);
11743         }
11744 	in_recovery = IN_RECOVERY(tp->t_flags);
11745 	if (tiwin > bbr->r_ctl.rc_high_rwnd)
11746 		bbr->r_ctl.rc_high_rwnd = tiwin;
11747 #ifdef BBR_INVARIANTS
11748 	if ((tp->t_inpcb->inp_flags & INP_DROPPED) ||
11749 	    (tp->t_inpcb->inp_flags2 & INP_FREED)) {
11750 		panic("tp:%p bbr:%p given a dropped inp:%p",
11751 		    tp, bbr, tp->t_inpcb);
11752 	}
11753 #endif
11754 	bbr->r_ctl.rc_flight_at_input = ctf_flight_size(tp,
11755 					    (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
11756 	bbr->rtt_valid = 0;
11757 	if (to.to_flags & TOF_TS) {
11758 		bbr->rc_ts_valid = 1;
11759 		bbr->r_ctl.last_inbound_ts = to.to_tsval;
11760 	} else {
11761 		bbr->rc_ts_valid = 0;
11762 		bbr->r_ctl.last_inbound_ts = 0;
11763 	}
11764 	retval = (*bbr->r_substate) (m, th, so,
11765 	    tp, &to, drop_hdrlen,
11766 	    tlen, tiwin, thflags, nxt_pkt);
11767 #ifdef BBR_INVARIANTS
11768 	if ((retval == 0) &&
11769 	    (tp->t_inpcb == NULL)) {
11770 		panic("retval:%d tp:%p t_inpcb:NULL state:%d",
11771 		    retval, tp, prev_state);
11772 	}
11773 #endif
11774 	if (nxt_pkt == 0)
11775 		BBR_STAT_INC(bbr_rlock_left_ret0);
11776 	else
11777 		BBR_STAT_INC(bbr_rlock_left_ret1);
11778 	if (retval == 0) {
11779 		/*
11780 		 * If retval is 1 the tcb is unlocked and most likely the tp
11781 		 * is gone.
11782 		 */
11783 		INP_WLOCK_ASSERT(tp->t_inpcb);
11784 		tcp_bbr_xmit_timer_commit(bbr, tp, cts);
11785 		if (bbr->rc_is_pkt_epoch_now)
11786 			bbr_set_pktepoch(bbr, cts, __LINE__);
11787 		bbr_check_bbr_for_state(bbr, cts, __LINE__, (bbr->r_ctl.rc_lost - lost));
11788 		if (nxt_pkt == 0) {
11789 			if (bbr->r_wanted_output != 0) {
11790 				bbr->rc_output_starts_timer = 0;
11791 				did_out = 1;
11792 				(void)tp->t_fb->tfb_tcp_output(tp);
11793 			} else
11794 				bbr_start_hpts_timer(bbr, tp, cts, 6, 0, 0);
11795 		}
11796 		if ((nxt_pkt == 0) &&
11797 		    ((bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK) == 0) &&
11798 		    (SEQ_GT(tp->snd_max, tp->snd_una) ||
11799 		     (tp->t_flags & TF_DELACK) ||
11800 		     ((V_tcp_always_keepalive || bbr->rc_inp->inp_socket->so_options & SO_KEEPALIVE) &&
11801 		      (tp->t_state <= TCPS_CLOSING)))) {
11802 			/*
11803 			 * We could not send (probably in the hpts but
11804 			 * stopped the timer)?
11805 			 */
11806 			if ((tp->snd_max == tp->snd_una) &&
11807 			    ((tp->t_flags & TF_DELACK) == 0) &&
11808 			    (bbr->rc_inp->inp_in_hpts) &&
11809 			    (bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
11810 				/*
11811 				 * keep alive not needed if we are hptsi
11812 				 * output yet
11813 				 */
11814 				;
11815 			} else {
11816 				if (bbr->rc_inp->inp_in_hpts) {
11817 					tcp_hpts_remove(bbr->rc_inp, HPTS_REMOVE_OUTPUT);
11818 					if ((bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
11819 					    (TSTMP_GT(lcts, bbr->rc_pacer_started))) {
11820 						uint32_t del;
11821 
11822 						del = lcts - bbr->rc_pacer_started;
11823 						if (bbr->r_ctl.rc_last_delay_val > del) {
11824 							BBR_STAT_INC(bbr_force_timer_start);
11825 							bbr->r_ctl.rc_last_delay_val -= del;
11826 							bbr->rc_pacer_started = lcts;
11827 						} else {
11828 							/* We are late */
11829 							bbr->r_ctl.rc_last_delay_val = 0;
11830 							BBR_STAT_INC(bbr_force_output);
11831 							(void)tp->t_fb->tfb_tcp_output(tp);
11832 						}
11833 					}
11834 				}
11835 				bbr_start_hpts_timer(bbr, tp, cts, 8, bbr->r_ctl.rc_last_delay_val,
11836 				    0);
11837 			}
11838 		} else if ((bbr->rc_output_starts_timer == 0) && (nxt_pkt == 0)) {
11839 			/* Do we have the correct timer running? */
11840 			bbr_timer_audit(tp, bbr, lcts, &so->so_snd);
11841 		}
11842 		/* Do we have a new state */
11843 		if (bbr->r_state != tp->t_state)
11844 			bbr_set_state(tp, bbr, tiwin);
11845 done_with_input:
11846 		bbr_log_doseg_done(bbr, cts, nxt_pkt, did_out);
11847 		if (did_out)
11848 			bbr->r_wanted_output = 0;
11849 #ifdef BBR_INVARIANTS
11850 		if (tp->t_inpcb == NULL) {
11851 			panic("OP:%d retval:%d tp:%p t_inpcb:NULL state:%d",
11852 			    did_out,
11853 			    retval, tp, prev_state);
11854 		}
11855 #endif
11856 	}
11857 	return (retval);
11858 }
11859 
11860 static void
11861 bbr_log_type_hrdwtso(struct tcpcb *tp, struct tcp_bbr *bbr, int len, int mod, int what_we_can_send)
11862 {
11863 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
11864 		union tcp_log_stackspecific log;
11865 		struct timeval tv;
11866 		uint32_t cts;
11867 
11868 		cts = tcp_get_usecs(&tv);
11869 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
11870 		log.u_bbr.flex1 = bbr->r_ctl.rc_pace_min_segs;
11871 		log.u_bbr.flex2 = what_we_can_send;
11872 		log.u_bbr.flex3 = bbr->r_ctl.rc_pace_max_segs;
11873 		log.u_bbr.flex4 = len;
11874 		log.u_bbr.flex5 = 0;
11875 		log.u_bbr.flex7 = mod;
11876 		log.u_bbr.flex8 = 1;
11877 		TCP_LOG_EVENTP(tp, NULL,
11878 		    &tp->t_inpcb->inp_socket->so_rcv,
11879 		    &tp->t_inpcb->inp_socket->so_snd,
11880 		    TCP_HDWR_TLS, 0,
11881 		    0, &log, false, &tv);
11882 	}
11883 }
11884 
11885 static void
11886 bbr_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
11887     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos)
11888 {
11889 	struct timeval tv;
11890 	int retval;
11891 
11892 	/* First lets see if we have old packets */
11893 	if (tp->t_in_pkt) {
11894 		if (ctf_do_queued_segments(so, tp, 1)) {
11895 			m_freem(m);
11896 			return;
11897 		}
11898 	}
11899 	if (m->m_flags & M_TSTMP_LRO) {
11900 		tv.tv_sec = m->m_pkthdr.rcv_tstmp /1000000000;
11901 		tv.tv_usec = (m->m_pkthdr.rcv_tstmp % 1000000000)/1000;
11902 	} else {
11903 		/* Should not be should we kassert instead? */
11904 		tcp_get_usecs(&tv);
11905 	}
11906 	retval = bbr_do_segment_nounlock(m, th, so, tp,
11907 					 drop_hdrlen, tlen, iptos, 0, &tv);
11908 	if (retval == 0)
11909 		INP_WUNLOCK(tp->t_inpcb);
11910 }
11911 
11912 /*
11913  * Return how much data can be sent without violating the
11914  * cwnd or rwnd.
11915  */
11916 
11917 static inline uint32_t
11918 bbr_what_can_we_send(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t sendwin,
11919     uint32_t avail, int32_t sb_offset, uint32_t cts)
11920 {
11921 	uint32_t len;
11922 
11923 	if (ctf_outstanding(tp) >= tp->snd_wnd) {
11924 		/* We never want to go over our peers rcv-window */
11925 		len = 0;
11926 	} else {
11927 		uint32_t flight;
11928 
11929 		flight = ctf_flight_size(tp, (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
11930 		if (flight >= sendwin) {
11931 			/*
11932 			 * We have in flight what we are allowed by cwnd (if
11933 			 * it was rwnd blocking it would have hit above out
11934 			 * >= tp->snd_wnd).
11935 			 */
11936 			return (0);
11937 		}
11938 		len = sendwin - flight;
11939 		if ((len + ctf_outstanding(tp)) > tp->snd_wnd) {
11940 			/* We would send too much (beyond the rwnd) */
11941 			len = tp->snd_wnd - ctf_outstanding(tp);
11942 		}
11943 		if ((len + sb_offset) > avail) {
11944 			/*
11945 			 * We don't have that much in the SB, how much is
11946 			 * there?
11947 			 */
11948 			len = avail - sb_offset;
11949 		}
11950 	}
11951 	return (len);
11952 }
11953 
11954 static inline void
11955 bbr_do_error_accounting(struct tcpcb *tp, struct tcp_bbr *bbr, struct bbr_sendmap *rsm, int32_t len, int32_t error)
11956 {
11957 #ifdef NETFLIX_STATS
11958 	KMOD_TCPSTAT_INC(tcps_sndpack_error);
11959 	KMOD_TCPSTAT_ADD(tcps_sndbyte_error, len);
11960 #endif
11961 }
11962 
11963 static inline void
11964 bbr_do_send_accounting(struct tcpcb *tp, struct tcp_bbr *bbr, struct bbr_sendmap *rsm, int32_t len, int32_t error)
11965 {
11966 	if (error) {
11967 		bbr_do_error_accounting(tp, bbr, rsm, len, error);
11968 		return;
11969 	}
11970 	if ((tp->t_flags & TF_FORCEDATA) && len == 1) {
11971 		/* Window probe */
11972 		KMOD_TCPSTAT_INC(tcps_sndprobe);
11973 #ifdef STATS
11974 		stats_voi_update_abs_u32(tp->t_stats,
11975 		    VOI_TCP_RETXPB, len);
11976 #endif
11977 	} else if (rsm) {
11978 		if (rsm->r_flags & BBR_TLP) {
11979 			/*
11980 			 * TLP should not count in retran count, but in its
11981 			 * own bin
11982 			 */
11983 #ifdef NETFLIX_STATS
11984 			tp->t_sndtlppack++;
11985 			tp->t_sndtlpbyte += len;
11986 			KMOD_TCPSTAT_INC(tcps_tlpresends);
11987 			KMOD_TCPSTAT_ADD(tcps_tlpresend_bytes, len);
11988 #endif
11989 		} else {
11990 			/* Retransmit */
11991 			tp->t_sndrexmitpack++;
11992 			KMOD_TCPSTAT_INC(tcps_sndrexmitpack);
11993 			KMOD_TCPSTAT_ADD(tcps_sndrexmitbyte, len);
11994 #ifdef STATS
11995 			stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RETXPB,
11996 			    len);
11997 #endif
11998 		}
11999 		/*
12000 		 * Logs in 0 - 8, 8 is all non probe_bw states 0-7 is
12001 		 * sub-state
12002 		 */
12003 		counter_u64_add(bbr_state_lost[rsm->r_bbr_state], len);
12004 		if (bbr->rc_bbr_state != BBR_STATE_PROBE_BW) {
12005 			/* Non probe_bw log in 1, 2, or 4. */
12006 			counter_u64_add(bbr_state_resend[bbr->rc_bbr_state], len);
12007 		} else {
12008 			/*
12009 			 * Log our probe state 3, and log also 5-13 to show
12010 			 * us the recovery sub-state for the send. This
12011 			 * means that 3 == (5+6+7+8+9+10+11+12+13)
12012 			 */
12013 			counter_u64_add(bbr_state_resend[BBR_STATE_PROBE_BW], len);
12014 			counter_u64_add(bbr_state_resend[(bbr_state_val(bbr) + 5)], len);
12015 		}
12016 		/* Place in both 16's the totals of retransmitted */
12017 		counter_u64_add(bbr_state_lost[16], len);
12018 		counter_u64_add(bbr_state_resend[16], len);
12019 		/* Place in 17's the total sent */
12020 		counter_u64_add(bbr_state_resend[17], len);
12021 		counter_u64_add(bbr_state_lost[17], len);
12022 
12023 	} else {
12024 		/* New sends */
12025 		KMOD_TCPSTAT_INC(tcps_sndpack);
12026 		KMOD_TCPSTAT_ADD(tcps_sndbyte, len);
12027 		/* Place in 17's the total sent */
12028 		counter_u64_add(bbr_state_resend[17], len);
12029 		counter_u64_add(bbr_state_lost[17], len);
12030 #ifdef STATS
12031 		stats_voi_update_abs_u64(tp->t_stats, VOI_TCP_TXPB,
12032 		    len);
12033 #endif
12034 	}
12035 }
12036 
12037 static void
12038 bbr_cwnd_limiting(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t in_level)
12039 {
12040 	if (bbr->rc_filled_pipe && bbr_target_cwnd_mult_limit && (bbr->rc_use_google == 0)) {
12041 		/*
12042 		 * Limit the cwnd to not be above N x the target plus whats
12043 		 * is outstanding. The target is based on the current b/w
12044 		 * estimate.
12045 		 */
12046 		uint32_t target;
12047 
12048 		target = bbr_get_target_cwnd(bbr, bbr_get_bw(bbr), BBR_UNIT);
12049 		target += ctf_outstanding(tp);
12050 		target *= bbr_target_cwnd_mult_limit;
12051 		if (tp->snd_cwnd > target)
12052 			tp->snd_cwnd = target;
12053 		bbr_log_type_cwndupd(bbr, 0, 0, 0, 10, 0, 0, __LINE__);
12054 	}
12055 }
12056 
12057 static int
12058 bbr_window_update_needed(struct tcpcb *tp, struct socket *so, uint32_t recwin, int32_t maxseg)
12059 {
12060 	/*
12061 	 * "adv" is the amount we could increase the window, taking into
12062 	 * account that we are limited by TCP_MAXWIN << tp->rcv_scale.
12063 	 */
12064 	uint32_t adv;
12065 	int32_t oldwin;
12066 
12067 	adv = min(recwin, TCP_MAXWIN << tp->rcv_scale);
12068 	if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt)) {
12069 		oldwin = (tp->rcv_adv - tp->rcv_nxt);
12070 		adv -= oldwin;
12071 	} else
12072 		oldwin = 0;
12073 
12074 	/*
12075 	 * If the new window size ends up being the same as the old size
12076 	 * when it is scaled, then don't force a window update.
12077 	 */
12078 	if (oldwin >> tp->rcv_scale == (adv + oldwin) >> tp->rcv_scale)
12079 		return (0);
12080 
12081 	if (adv >= (2 * maxseg) &&
12082 	    (adv >= (so->so_rcv.sb_hiwat / 4) ||
12083 	    recwin <= (so->so_rcv.sb_hiwat / 8) ||
12084 	    so->so_rcv.sb_hiwat <= 8 * maxseg)) {
12085 		return (1);
12086 	}
12087 	if (2 * adv >= (int32_t) so->so_rcv.sb_hiwat)
12088 		return (1);
12089 	return (0);
12090 }
12091 
12092 /*
12093  * Return 0 on success and a errno on failure to send.
12094  * Note that a 0 return may not mean we sent anything
12095  * if the TCB was on the hpts. A non-zero return
12096  * does indicate the error we got from ip[6]_output.
12097  */
12098 static int
12099 bbr_output_wtime(struct tcpcb *tp, const struct timeval *tv)
12100 {
12101 	struct socket *so;
12102 	int32_t len;
12103 	uint32_t cts;
12104 	uint32_t recwin, sendwin;
12105 	int32_t sb_offset;
12106 	int32_t flags, abandon, error = 0;
12107 	struct tcp_log_buffer *lgb = NULL;
12108 	struct mbuf *m;
12109 	struct mbuf *mb;
12110 	uint32_t if_hw_tsomaxsegcount = 0;
12111 	uint32_t if_hw_tsomaxsegsize = 0;
12112 	uint32_t if_hw_tsomax = 0;
12113 	struct ip *ip = NULL;
12114 #ifdef TCPDEBUG
12115 	struct ipovly *ipov = NULL;
12116 #endif
12117 	struct tcp_bbr *bbr;
12118 	struct tcphdr *th;
12119 #ifdef NETFLIX_TCPOUDP
12120 	struct udphdr *udp = NULL;
12121 #endif
12122 	u_char opt[TCP_MAXOLEN];
12123 	unsigned ipoptlen, optlen, hdrlen;
12124 #ifdef NETFLIX_TCPOUDP
12125 	unsigned ulen;
12126 #endif
12127 	uint32_t bbr_seq;
12128 	uint32_t delay_calc=0;
12129 	uint8_t doing_tlp = 0;
12130 	uint8_t local_options;
12131 #ifdef BBR_INVARIANTS
12132 	uint8_t doing_retran_from = 0;
12133 	uint8_t picked_up_retran = 0;
12134 #endif
12135 	uint8_t wanted_cookie = 0;
12136 	uint8_t more_to_rxt=0;
12137 	int32_t prefetch_so_done = 0;
12138 	int32_t prefetch_rsm = 0;
12139  	uint32_t what_we_can = 0;
12140 	uint32_t tot_len = 0;
12141 	uint32_t rtr_cnt = 0;
12142 	uint32_t maxseg, pace_max_segs, p_maxseg;
12143 	int32_t csum_flags;
12144  	int32_t hw_tls;
12145 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
12146 	unsigned ipsec_optlen = 0;
12147 
12148 #endif
12149 	volatile int32_t sack_rxmit;
12150 	struct bbr_sendmap *rsm = NULL;
12151 	int32_t tso, mtu;
12152 	int force_tso = 0;
12153 	struct tcpopt to;
12154 	int32_t slot = 0;
12155 	struct inpcb *inp;
12156 	struct sockbuf *sb;
12157 	uint32_t hpts_calling;
12158 #ifdef INET6
12159 	struct ip6_hdr *ip6 = NULL;
12160 	int32_t isipv6;
12161 #endif
12162 	uint8_t app_limited = BBR_JR_SENT_DATA;
12163 	uint8_t filled_all = 0;
12164 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
12165 	/* We take a cache hit here */
12166 	memcpy(&bbr->rc_tv, tv, sizeof(struct timeval));
12167 	cts = tcp_tv_to_usectick(&bbr->rc_tv);
12168 	inp = bbr->rc_inp;
12169 	so = inp->inp_socket;
12170 	sb = &so->so_snd;
12171 #ifdef KERN_TLS
12172  	if (sb->sb_flags & SB_TLS_IFNET)
12173  		hw_tls = 1;
12174  	else
12175 #endif
12176  		hw_tls = 0;
12177 	kern_prefetch(sb, &maxseg);
12178 	maxseg = tp->t_maxseg - bbr->rc_last_options;
12179 	if (bbr_minseg(bbr) < maxseg) {
12180 		tcp_bbr_tso_size_check(bbr, cts);
12181 	}
12182 	/* Remove any flags that indicate we are pacing on the inp  */
12183 	pace_max_segs = bbr->r_ctl.rc_pace_max_segs;
12184 	p_maxseg = min(maxseg, pace_max_segs);
12185 	INP_WLOCK_ASSERT(inp);
12186 #ifdef TCP_OFFLOAD
12187 	if (tp->t_flags & TF_TOE)
12188 		return (tcp_offload_output(tp));
12189 #endif
12190 
12191 #ifdef INET6
12192 	if (bbr->r_state) {
12193 		/* Use the cache line loaded if possible */
12194 		isipv6 = bbr->r_is_v6;
12195 	} else {
12196 		isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
12197 	}
12198 #endif
12199 	if (((bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0) &&
12200 	    inp->inp_in_hpts) {
12201 		/*
12202 		 * We are on the hpts for some timer but not hptsi output.
12203 		 * Possibly remove from the hpts so we can send/recv etc.
12204 		 */
12205 		if ((tp->t_flags & TF_ACKNOW) == 0) {
12206 			/*
12207 			 * No immediate demand right now to send an ack, but
12208 			 * the user may have read, making room for new data
12209 			 * (a window update). If so we may want to cancel
12210 			 * whatever timer is running (KEEP/DEL-ACK?) and
12211 			 * continue to send out a window update. Or we may
12212 			 * have gotten more data into the socket buffer to
12213 			 * send.
12214 			 */
12215 			recwin = min(max(sbspace(&so->so_rcv), 0),
12216 			    TCP_MAXWIN << tp->rcv_scale);
12217 			if ((bbr_window_update_needed(tp, so, recwin, maxseg) == 0) &&
12218 			    ((sbavail(sb) + ((tcp_outflags[tp->t_state] & TH_FIN) ? 1 : 0)) <=
12219 			    (tp->snd_max - tp->snd_una))) {
12220 				/*
12221 				 * Nothing new to send and no window update
12222 				 * is needed to send. Lets just return and
12223 				 * let the timer-run off.
12224 				 */
12225 				return (0);
12226 			}
12227 		}
12228 		tcp_hpts_remove(inp, HPTS_REMOVE_OUTPUT);
12229 		bbr_timer_cancel(bbr, __LINE__, cts);
12230 	}
12231 	if (bbr->r_ctl.rc_last_delay_val) {
12232 		/* Calculate a rough delay for early escape to sending  */
12233 		if (SEQ_GT(cts, bbr->rc_pacer_started))
12234 			delay_calc = cts - bbr->rc_pacer_started;
12235 		if (delay_calc >= bbr->r_ctl.rc_last_delay_val)
12236 			delay_calc -= bbr->r_ctl.rc_last_delay_val;
12237 		else
12238 			delay_calc = 0;
12239 	}
12240 	/* Mark that we have called bbr_output(). */
12241 	if ((bbr->r_timer_override) ||
12242 	    (tp->t_flags & TF_FORCEDATA) ||
12243 	    (tp->t_state < TCPS_ESTABLISHED)) {
12244 		/* Timeouts or early states are exempt */
12245 		if (inp->inp_in_hpts)
12246 			tcp_hpts_remove(inp, HPTS_REMOVE_OUTPUT);
12247 	} else if (inp->inp_in_hpts) {
12248 		if ((bbr->r_ctl.rc_last_delay_val) &&
12249 		    (bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
12250 		    delay_calc) {
12251 			/*
12252 			 * We were being paced for output and the delay has
12253 			 * already exceeded when we were supposed to be
12254 			 * called, lets go ahead and pull out of the hpts
12255 			 * and call output.
12256 			 */
12257 			counter_u64_add(bbr_out_size[TCP_MSS_ACCT_LATE], 1);
12258 			bbr->r_ctl.rc_last_delay_val = 0;
12259 			tcp_hpts_remove(inp, HPTS_REMOVE_OUTPUT);
12260 		} else if (tp->t_state == TCPS_CLOSED) {
12261 			bbr->r_ctl.rc_last_delay_val = 0;
12262 			tcp_hpts_remove(inp, HPTS_REMOVE_OUTPUT);
12263 		} else {
12264 			/*
12265 			 * On the hpts, you shall not pass! even if ACKNOW
12266 			 * is on, we will when the hpts fires, unless of
12267 			 * course we are overdue.
12268 			 */
12269 			counter_u64_add(bbr_out_size[TCP_MSS_ACCT_INPACE], 1);
12270 			return (0);
12271 		}
12272 	}
12273 	bbr->rc_cwnd_limited = 0;
12274 	if (bbr->r_ctl.rc_last_delay_val) {
12275 		/* recalculate the real delay and deal with over/under  */
12276 		if (SEQ_GT(cts, bbr->rc_pacer_started))
12277 			delay_calc = cts - bbr->rc_pacer_started;
12278 		else
12279 			delay_calc = 0;
12280 		if (delay_calc >= bbr->r_ctl.rc_last_delay_val)
12281 			/* Setup the delay which will be added in */
12282 			delay_calc -= bbr->r_ctl.rc_last_delay_val;
12283 		else {
12284 			/*
12285 			 * We are early setup to adjust
12286 			 * our slot time.
12287 			 */
12288 			uint64_t merged_val;
12289 
12290 			bbr->r_ctl.rc_agg_early += (bbr->r_ctl.rc_last_delay_val - delay_calc);
12291 			bbr->r_agg_early_set = 1;
12292 			if (bbr->r_ctl.rc_hptsi_agg_delay) {
12293 				if (bbr->r_ctl.rc_hptsi_agg_delay >= bbr->r_ctl.rc_agg_early) {
12294 					/* Nope our previous late cancels out the early */
12295 					bbr->r_ctl.rc_hptsi_agg_delay -= bbr->r_ctl.rc_agg_early;
12296 					bbr->r_agg_early_set = 0;
12297 					bbr->r_ctl.rc_agg_early = 0;
12298 				} else {
12299 					bbr->r_ctl.rc_agg_early -= bbr->r_ctl.rc_hptsi_agg_delay;
12300 					bbr->r_ctl.rc_hptsi_agg_delay = 0;
12301 				}
12302 			}
12303 			merged_val = bbr->rc_pacer_started;
12304 			merged_val <<= 32;
12305 			merged_val |= bbr->r_ctl.rc_last_delay_val;
12306 			bbr_log_pacing_delay_calc(bbr, inp->inp_hpts_calls,
12307 						 bbr->r_ctl.rc_agg_early, cts, delay_calc, merged_val,
12308 						 bbr->r_agg_early_set, 3);
12309 			bbr->r_ctl.rc_last_delay_val = 0;
12310 			BBR_STAT_INC(bbr_early);
12311 			delay_calc = 0;
12312 		}
12313 	} else {
12314 		/* We were not delayed due to hptsi */
12315 		if (bbr->r_agg_early_set)
12316 			bbr->r_ctl.rc_agg_early = 0;
12317 		bbr->r_agg_early_set = 0;
12318 		delay_calc = 0;
12319 	}
12320 	if (delay_calc) {
12321 		/*
12322 		 * We had a hptsi delay which means we are falling behind on
12323 		 * sending at the expected rate. Calculate an extra amount
12324 		 * of data we can send, if any, to put us back on track.
12325 		 */
12326 		if ((bbr->r_ctl.rc_hptsi_agg_delay + delay_calc) < bbr->r_ctl.rc_hptsi_agg_delay)
12327 			bbr->r_ctl.rc_hptsi_agg_delay = 0xffffffff;
12328 		else
12329 			bbr->r_ctl.rc_hptsi_agg_delay += delay_calc;
12330 	}
12331 	sendwin = min(tp->snd_wnd, tp->snd_cwnd);
12332 	if ((tp->snd_una == tp->snd_max) &&
12333 	    (bbr->rc_bbr_state != BBR_STATE_IDLE_EXIT) &&
12334 	    (sbavail(sb))) {
12335 		/*
12336 		 * Ok we have been idle with nothing outstanding
12337 		 * we possibly need to start fresh with either a new
12338 		 * suite of states or a fast-ramp up.
12339 		 */
12340 		bbr_restart_after_idle(bbr,
12341 				       cts, bbr_calc_time(cts, bbr->r_ctl.rc_went_idle_time));
12342 	}
12343 	/*
12344 	 * Now was there a hptsi delay where we are behind? We only count
12345 	 * being behind if: a) We are not in recovery. b) There was a delay.
12346 	 * <and> c) We had room to send something.
12347 	 *
12348 	 */
12349 	hpts_calling = inp->inp_hpts_calls;
12350 	inp->inp_hpts_calls = 0;
12351 	if (bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK) {
12352 		if (bbr_process_timers(tp, bbr, cts, hpts_calling)) {
12353 			counter_u64_add(bbr_out_size[TCP_MSS_ACCT_ATIMER], 1);
12354 			return (0);
12355 		}
12356 	}
12357 	bbr->rc_inp->inp_flags2 &= ~INP_MBUF_QUEUE_READY;
12358 	if (hpts_calling &&
12359 	    (bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
12360 		bbr->r_ctl.rc_last_delay_val = 0;
12361 	}
12362 	bbr->r_timer_override = 0;
12363 	bbr->r_wanted_output = 0;
12364 	/*
12365 	 * For TFO connections in SYN_RECEIVED, only allow the initial
12366 	 * SYN|ACK and those sent by the retransmit timer.
12367 	 */
12368 	if (IS_FASTOPEN(tp->t_flags) &&
12369 	    ((tp->t_state == TCPS_SYN_RECEIVED) ||
12370 	     (tp->t_state == TCPS_SYN_SENT)) &&
12371 	    SEQ_GT(tp->snd_max, tp->snd_una) &&	/* initial SYN or SYN|ACK sent */
12372 	    (tp->t_rxtshift == 0)) {	/* not a retransmit */
12373 		return (0);
12374 	}
12375 	/*
12376 	 * Before sending anything check for a state update. For hpts
12377 	 * calling without input this is important. If its input calling
12378 	 * then this was already done.
12379 	 */
12380 	if (bbr->rc_use_google == 0)
12381 		bbr_check_bbr_for_state(bbr, cts, __LINE__, 0);
12382 again:
12383 	/*
12384 	 * If we've recently taken a timeout, snd_max will be greater than
12385 	 * snd_max. BBR in general does not pay much attention to snd_nxt
12386 	 * for historic reasons the persist timer still uses it. This means
12387 	 * we have to look at it. All retransmissions that are not persits
12388 	 * use the rsm that needs to be sent so snd_nxt is ignored. At the
12389 	 * end of this routine we pull snd_nxt always up to snd_max.
12390 	 */
12391 	doing_tlp = 0;
12392 #ifdef BBR_INVARIANTS
12393 	doing_retran_from = picked_up_retran = 0;
12394 #endif
12395 	error = 0;
12396 	tso = 0;
12397 	slot = 0;
12398 	mtu = 0;
12399 	sendwin = min(tp->snd_wnd, tp->snd_cwnd);
12400 	sb_offset = tp->snd_max - tp->snd_una;
12401 	flags = tcp_outflags[tp->t_state];
12402 	sack_rxmit = 0;
12403 	len = 0;
12404 	rsm = NULL;
12405 	if (flags & TH_RST) {
12406 		SOCKBUF_LOCK(sb);
12407 		goto send;
12408 	}
12409 recheck_resend:
12410 	while (bbr->r_ctl.rc_free_cnt < bbr_min_req_free) {
12411 		/* We need to always have one in reserve */
12412 		rsm = bbr_alloc(bbr);
12413 		if (rsm == NULL) {
12414 			error = ENOMEM;
12415 			/* Lie to get on the hpts */
12416 			tot_len = tp->t_maxseg;
12417 			if (hpts_calling)
12418 				/* Retry in a ms */
12419 				slot = 1001;
12420 			goto just_return_nolock;
12421 		}
12422 		TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_free, rsm, r_next);
12423 		bbr->r_ctl.rc_free_cnt++;
12424 		rsm = NULL;
12425 	}
12426 	/* What do we send, a resend? */
12427 	if (bbr->r_ctl.rc_resend == NULL) {
12428 		/* Check for rack timeout */
12429 		bbr->r_ctl.rc_resend = bbr_check_recovery_mode(tp, bbr, cts);
12430 		if (bbr->r_ctl.rc_resend) {
12431 #ifdef BBR_INVARIANTS
12432 			picked_up_retran = 1;
12433 #endif
12434 			bbr_cong_signal(tp, NULL, CC_NDUPACK, bbr->r_ctl.rc_resend);
12435 		}
12436 	}
12437 	if (bbr->r_ctl.rc_resend) {
12438 		rsm = bbr->r_ctl.rc_resend;
12439 #ifdef BBR_INVARIANTS
12440 		doing_retran_from = 1;
12441 #endif
12442 		/* Remove any TLP flags its a RACK or T-O */
12443 		rsm->r_flags &= ~BBR_TLP;
12444 		bbr->r_ctl.rc_resend = NULL;
12445 		if (SEQ_LT(rsm->r_start, tp->snd_una)) {
12446 #ifdef BBR_INVARIANTS
12447 			panic("Huh, tp:%p bbr:%p rsm:%p start:%u < snd_una:%u\n",
12448 			    tp, bbr, rsm, rsm->r_start, tp->snd_una);
12449 			goto recheck_resend;
12450 #else
12451 			/* TSNH */
12452 			rsm = NULL;
12453 			goto recheck_resend;
12454 #endif
12455 		}
12456 		rtr_cnt++;
12457 		if (rsm->r_flags & BBR_HAS_SYN) {
12458 			/* Only retransmit a SYN by itself */
12459 			len = 0;
12460 			if ((flags & TH_SYN) == 0) {
12461 				/* Huh something is wrong */
12462 				rsm->r_start++;
12463 				if (rsm->r_start == rsm->r_end) {
12464 					/* Clean it up, somehow we missed the ack? */
12465 					bbr_log_syn(tp, NULL);
12466 				} else {
12467 					/* TFO with data? */
12468 					rsm->r_flags &= ~BBR_HAS_SYN;
12469 					len = rsm->r_end - rsm->r_start;
12470 				}
12471 			} else {
12472 				/* Retransmitting SYN */
12473 				rsm = NULL;
12474 				SOCKBUF_LOCK(sb);
12475 				goto send;
12476 			}
12477 		} else
12478 			len = rsm->r_end - rsm->r_start;
12479 		if ((bbr->rc_resends_use_tso == 0) &&
12480 #ifdef KERN_TLS
12481 		    ((sb->sb_flags & SB_TLS_IFNET) == 0) &&
12482 #endif
12483 		    (len > maxseg)) {
12484 			len = maxseg;
12485 			more_to_rxt = 1;
12486 		}
12487 		sb_offset = rsm->r_start - tp->snd_una;
12488 		if (len > 0) {
12489 			sack_rxmit = 1;
12490 			KMOD_TCPSTAT_INC(tcps_sack_rexmits);
12491 			KMOD_TCPSTAT_ADD(tcps_sack_rexmit_bytes,
12492 			    min(len, maxseg));
12493 		} else {
12494 			/* I dont think this can happen */
12495 			rsm = NULL;
12496 			goto recheck_resend;
12497 		}
12498 		BBR_STAT_INC(bbr_resends_set);
12499 	} else if (bbr->r_ctl.rc_tlp_send) {
12500 		/*
12501 		 * Tail loss probe
12502 		 */
12503 		doing_tlp = 1;
12504 		rsm = bbr->r_ctl.rc_tlp_send;
12505 		bbr->r_ctl.rc_tlp_send = NULL;
12506 		sack_rxmit = 1;
12507 		len = rsm->r_end - rsm->r_start;
12508 		rtr_cnt++;
12509 		if ((bbr->rc_resends_use_tso == 0) && (len > maxseg))
12510 			len = maxseg;
12511 
12512 		if (SEQ_GT(tp->snd_una, rsm->r_start)) {
12513 #ifdef BBR_INVARIANTS
12514 			panic("tp:%p bbc:%p snd_una:%u rsm:%p r_start:%u",
12515 			    tp, bbr, tp->snd_una, rsm, rsm->r_start);
12516 #else
12517 			/* TSNH */
12518 			rsm = NULL;
12519 			goto recheck_resend;
12520 #endif
12521 		}
12522 		sb_offset = rsm->r_start - tp->snd_una;
12523 		BBR_STAT_INC(bbr_tlp_set);
12524 	}
12525 	/*
12526 	 * Enforce a connection sendmap count limit if set
12527 	 * as long as we are not retransmiting.
12528 	 */
12529 	if ((rsm == NULL) &&
12530 	    (V_tcp_map_entries_limit > 0) &&
12531 	    (bbr->r_ctl.rc_num_maps_alloced >= V_tcp_map_entries_limit)) {
12532 		BBR_STAT_INC(bbr_alloc_limited);
12533 		if (!bbr->alloc_limit_reported) {
12534 			bbr->alloc_limit_reported = 1;
12535 			BBR_STAT_INC(bbr_alloc_limited_conns);
12536 		}
12537 		goto just_return_nolock;
12538 	}
12539 #ifdef BBR_INVARIANTS
12540 	if (rsm && SEQ_LT(rsm->r_start, tp->snd_una)) {
12541 		panic("tp:%p bbr:%p rsm:%p sb_offset:%u len:%u",
12542 		    tp, bbr, rsm, sb_offset, len);
12543 	}
12544 #endif
12545 	/*
12546 	 * Get standard flags, and add SYN or FIN if requested by 'hidden'
12547 	 * state flags.
12548 	 */
12549 	if (tp->t_flags & TF_NEEDFIN && (rsm == NULL))
12550 		flags |= TH_FIN;
12551 	if (tp->t_flags & TF_NEEDSYN)
12552 		flags |= TH_SYN;
12553 
12554 	if (rsm && (rsm->r_flags & BBR_HAS_FIN)) {
12555 		/* we are retransmitting the fin */
12556 		len--;
12557 		if (len) {
12558 			/*
12559 			 * When retransmitting data do *not* include the
12560 			 * FIN. This could happen from a TLP probe if we
12561 			 * allowed data with a FIN.
12562 			 */
12563 			flags &= ~TH_FIN;
12564 		}
12565 	} else if (rsm) {
12566 		if (flags & TH_FIN)
12567 			flags &= ~TH_FIN;
12568 	}
12569 	if ((sack_rxmit == 0) && (prefetch_rsm == 0)) {
12570 		void *end_rsm;
12571 
12572 		end_rsm = TAILQ_LAST_FAST(&bbr->r_ctl.rc_tmap, bbr_sendmap, r_tnext);
12573 		if (end_rsm)
12574 			kern_prefetch(end_rsm, &prefetch_rsm);
12575 		prefetch_rsm = 1;
12576 	}
12577 	SOCKBUF_LOCK(sb);
12578 	/*
12579 	 * If in persist timeout with window of 0, send 1 byte. Otherwise,
12580 	 * if window is small but nonzero and time TF_SENTFIN expired, we
12581 	 * will send what we can and go to transmit state.
12582 	 */
12583 	if (tp->t_flags & TF_FORCEDATA) {
12584 		if ((sendwin == 0) || (sendwin <= (tp->snd_max - tp->snd_una))) {
12585 			/*
12586 			 * If we still have some data to send, then clear
12587 			 * the FIN bit.  Usually this would happen below
12588 			 * when it realizes that we aren't sending all the
12589 			 * data.  However, if we have exactly 1 byte of
12590 			 * unsent data, then it won't clear the FIN bit
12591 			 * below, and if we are in persist state, we wind up
12592 			 * sending the packet without recording that we sent
12593 			 * the FIN bit.
12594 			 *
12595 			 * We can't just blindly clear the FIN bit, because
12596 			 * if we don't have any more data to send then the
12597 			 * probe will be the FIN itself.
12598 			 */
12599 			if (sb_offset < sbused(sb))
12600 				flags &= ~TH_FIN;
12601 			sendwin = 1;
12602 		} else {
12603 			if ((bbr->rc_in_persist != 0) &&
12604  			    (tp->snd_wnd >= min((bbr->r_ctl.rc_high_rwnd/2),
12605 					       bbr_minseg(bbr)))) {
12606 				/* Exit persists if there is space */
12607 				bbr_exit_persist(tp, bbr, cts, __LINE__);
12608 			}
12609 			if (rsm == NULL) {
12610 				/*
12611 				 * If we are dropping persist mode then we
12612 				 * need to correct sb_offset if not a
12613 				 * retransmit.
12614 				 */
12615 				sb_offset = tp->snd_max - tp->snd_una;
12616 			}
12617 		}
12618 	}
12619 	/*
12620 	 * If snd_nxt == snd_max and we have transmitted a FIN, the
12621 	 * sb_offset will be > 0 even if so_snd.sb_cc is 0, resulting in a
12622 	 * negative length.  This can also occur when TCP opens up its
12623 	 * congestion window while receiving additional duplicate acks after
12624 	 * fast-retransmit because TCP will reset snd_nxt to snd_max after
12625 	 * the fast-retransmit.
12626 	 *
12627 	 * In the normal retransmit-FIN-only case, however, snd_nxt will be
12628 	 * set to snd_una, the sb_offset will be 0, and the length may wind
12629 	 * up 0.
12630 	 *
12631 	 * If sack_rxmit is true we are retransmitting from the scoreboard
12632 	 * in which case len is already set.
12633 	 */
12634 	if (sack_rxmit == 0) {
12635 		uint32_t avail;
12636 
12637 		avail = sbavail(sb);
12638 		if (SEQ_GT(tp->snd_max, tp->snd_una))
12639 			sb_offset = tp->snd_max - tp->snd_una;
12640 		else
12641 			sb_offset = 0;
12642 		if (bbr->rc_tlp_new_data) {
12643 			/* TLP is forcing out new data */
12644 			uint32_t tlplen;
12645 
12646 			doing_tlp = 1;
12647 			tlplen = maxseg;
12648 
12649 			if (tlplen > (uint32_t)(avail - sb_offset)) {
12650 				tlplen = (uint32_t)(avail - sb_offset);
12651 			}
12652 			if (tlplen > tp->snd_wnd) {
12653 				len = tp->snd_wnd;
12654 			} else {
12655 				len = tlplen;
12656 			}
12657 			bbr->rc_tlp_new_data = 0;
12658 		} else {
12659 			what_we_can = len = bbr_what_can_we_send(tp, bbr, sendwin, avail, sb_offset, cts);
12660 			if ((len < p_maxseg) &&
12661 			    (bbr->rc_in_persist == 0) &&
12662 			    (ctf_outstanding(tp) >= (2 * p_maxseg)) &&
12663 			    ((avail - sb_offset) >= p_maxseg)) {
12664 				/*
12665 				 * We are not completing whats in the socket
12666 				 * buffer (i.e. there is at least a segment
12667 				 * waiting to send) and we have 2 or more
12668 				 * segments outstanding. There is no sense
12669 				 * of sending a little piece. Lets defer and
12670 				 * and wait until we can send a whole
12671 				 * segment.
12672 				 */
12673 				len = 0;
12674 			}
12675 			if ((tp->t_flags & TF_FORCEDATA) && (bbr->rc_in_persist)) {
12676 				/*
12677 				 * We are in persists, figure out if
12678 				 * a retransmit is available (maybe the previous
12679 				 * persists we sent) or if we have to send new
12680 				 * data.
12681 				 */
12682 				rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
12683 				if (rsm) {
12684 					len = rsm->r_end - rsm->r_start;
12685 					if (rsm->r_flags & BBR_HAS_FIN)
12686 						len--;
12687 					if ((bbr->rc_resends_use_tso == 0) && (len > maxseg))
12688 						len = maxseg;
12689 					if (len > 1)
12690 						BBR_STAT_INC(bbr_persist_reneg);
12691 					/*
12692 					 * XXXrrs we could force the len to
12693 					 * 1 byte here to cause the chunk to
12694 					 * split apart.. but that would then
12695 					 * mean we always retransmit it as
12696 					 * one byte even after the window
12697 					 * opens.
12698 					 */
12699 					sack_rxmit = 1;
12700 					sb_offset = rsm->r_start - tp->snd_una;
12701 				} else {
12702 					/*
12703 					 * First time through in persists or peer
12704 					 * acked our one byte. Though we do have
12705 					 * to have something in the sb.
12706 					 */
12707 					len = 1;
12708 					sb_offset = 0;
12709 					if (avail == 0)
12710 					    len = 0;
12711 				}
12712 			}
12713 		}
12714 	}
12715 	if (prefetch_so_done == 0) {
12716 		kern_prefetch(so, &prefetch_so_done);
12717 		prefetch_so_done = 1;
12718 	}
12719 	/*
12720 	 * Lop off SYN bit if it has already been sent.  However, if this is
12721 	 * SYN-SENT state and if segment contains data and if we don't know
12722 	 * that foreign host supports TAO, suppress sending segment.
12723 	 */
12724 	if ((flags & TH_SYN) && (rsm == NULL) &&
12725 	    SEQ_GT(tp->snd_max, tp->snd_una)) {
12726 		if (tp->t_state != TCPS_SYN_RECEIVED)
12727 			flags &= ~TH_SYN;
12728 		/*
12729 		 * When sending additional segments following a TFO SYN|ACK,
12730 		 * do not include the SYN bit.
12731 		 */
12732 		if (IS_FASTOPEN(tp->t_flags) &&
12733 		    (tp->t_state == TCPS_SYN_RECEIVED))
12734 			flags &= ~TH_SYN;
12735 		sb_offset--, len++;
12736 		if (sbavail(sb) == 0)
12737 			len = 0;
12738 	} else if ((flags & TH_SYN) && rsm) {
12739 		/*
12740 		 * Subtract one from the len for the SYN being
12741 		 * retransmitted.
12742 		 */
12743 		len--;
12744 	}
12745 	/*
12746 	 * Be careful not to send data and/or FIN on SYN segments. This
12747 	 * measure is needed to prevent interoperability problems with not
12748 	 * fully conformant TCP implementations.
12749 	 */
12750 	if ((flags & TH_SYN) && (tp->t_flags & TF_NOOPT)) {
12751 		len = 0;
12752 		flags &= ~TH_FIN;
12753 	}
12754 	/*
12755 	 * On TFO sockets, ensure no data is sent in the following cases:
12756 	 *
12757 	 *  - When retransmitting SYN|ACK on a passively-created socket
12758 	 *  - When retransmitting SYN on an actively created socket
12759 	 *  - When sending a zero-length cookie (cookie request) on an
12760 	 *    actively created socket
12761 	 *  - When the socket is in the CLOSED state (RST is being sent)
12762 	 */
12763 	if (IS_FASTOPEN(tp->t_flags) &&
12764 	    (((flags & TH_SYN) && (tp->t_rxtshift > 0)) ||
12765 	     ((tp->t_state == TCPS_SYN_SENT) &&
12766 	      (tp->t_tfo_client_cookie_len == 0)) ||
12767 	     (flags & TH_RST))) {
12768 		len = 0;
12769 		sack_rxmit = 0;
12770 		rsm = NULL;
12771 	}
12772 	/* Without fast-open there should never be data sent on a SYN */
12773 	if ((flags & TH_SYN) && (!IS_FASTOPEN(tp->t_flags)))
12774 		len = 0;
12775 	if (len <= 0) {
12776 		/*
12777 		 * If FIN has been sent but not acked, but we haven't been
12778 		 * called to retransmit, len will be < 0.  Otherwise, window
12779 		 * shrank after we sent into it.  If window shrank to 0,
12780 		 * cancel pending retransmit, pull snd_nxt back to (closed)
12781 		 * window, and set the persist timer if it isn't already
12782 		 * going.  If the window didn't close completely, just wait
12783 		 * for an ACK.
12784 		 *
12785 		 * We also do a general check here to ensure that we will
12786 		 * set the persist timer when we have data to send, but a
12787 		 * 0-byte window. This makes sure the persist timer is set
12788 		 * even if the packet hits one of the "goto send" lines
12789 		 * below.
12790 		 */
12791 		len = 0;
12792 		if ((tp->snd_wnd == 0) &&
12793 		    (TCPS_HAVEESTABLISHED(tp->t_state)) &&
12794 		    (tp->snd_una == tp->snd_max) &&
12795 		    (sb_offset < (int)sbavail(sb))) {
12796 			/*
12797 			 * Not enough room in the rwnd to send
12798 			 * a paced segment out.
12799 			 */
12800 			bbr_enter_persist(tp, bbr, cts, __LINE__);
12801 		}
12802 	} else if ((rsm == NULL) &&
12803 		   (doing_tlp == 0) &&
12804 		   (len < bbr->r_ctl.rc_pace_max_segs)) {
12805 		/*
12806 		 * We are not sending a full segment for
12807 		 * some reason. Should we not send anything (think
12808 		 * sws or persists)?
12809 		 */
12810 		if ((tp->snd_wnd < min((bbr->r_ctl.rc_high_rwnd/2), bbr_minseg(bbr))) &&
12811 		    (TCPS_HAVEESTABLISHED(tp->t_state)) &&
12812 		    (len < (int)(sbavail(sb) - sb_offset))) {
12813 			/*
12814 			 * Here the rwnd is less than
12815 			 * the pacing size, this is not a retransmit,
12816 			 * we are established and
12817 			 * the send is not the last in the socket buffer
12818 			 * lets not send, and possibly enter persists.
12819 			 */
12820 			len = 0;
12821 			if (tp->snd_max == tp->snd_una)
12822 				bbr_enter_persist(tp, bbr, cts, __LINE__);
12823 		} else if ((tp->snd_cwnd >= bbr->r_ctl.rc_pace_max_segs) &&
12824 			   (ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
12825 						 bbr->r_ctl.rc_lost_bytes)) > (2 * maxseg)) &&
12826 			   (len < (int)(sbavail(sb) - sb_offset)) &&
12827 			   (len < bbr_minseg(bbr))) {
12828 			/*
12829 			 * Here we are not retransmitting, and
12830 			 * the cwnd is not so small that we could
12831 			 * not send at least a min size (rxt timer
12832 			 * not having gone off), We have 2 segments or
12833 			 * more already in flight, its not the tail end
12834 			 * of the socket buffer  and the cwnd is blocking
12835 			 * us from sending out minimum pacing segment size.
12836 			 * Lets not send anything.
12837 			 */
12838 			bbr->rc_cwnd_limited = 1;
12839 			len = 0;
12840 		} else if (((tp->snd_wnd - ctf_outstanding(tp)) <
12841 			    min((bbr->r_ctl.rc_high_rwnd/2), bbr_minseg(bbr))) &&
12842 			   (ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
12843 						 bbr->r_ctl.rc_lost_bytes)) > (2 * maxseg)) &&
12844 			   (len < (int)(sbavail(sb) - sb_offset)) &&
12845 			   (TCPS_HAVEESTABLISHED(tp->t_state))) {
12846 			/*
12847 			 * Here we have a send window but we have
12848 			 * filled it up and we can't send another pacing segment.
12849 			 * We also have in flight more than 2 segments
12850 			 * and we are not completing the sb i.e. we allow
12851 			 * the last bytes of the sb to go out even if
12852 			 * its not a full pacing segment.
12853 			 */
12854 			len = 0;
12855 		}
12856 	}
12857 	/* len will be >= 0 after this point. */
12858 	KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__));
12859 	tcp_sndbuf_autoscale(tp, so, sendwin);
12860 	/*
12861 	 *
12862 	 */
12863 	if (bbr->rc_in_persist &&
12864 	    len &&
12865 	    (rsm == NULL) &&
12866 	    (len < min((bbr->r_ctl.rc_high_rwnd/2), bbr->r_ctl.rc_pace_max_segs))) {
12867 		/*
12868 		 * We are in persist, not doing a retransmit and don't have enough space
12869 		 * yet to send a full TSO. So is it at the end of the sb
12870 		 * if so we need to send else nuke to 0 and don't send.
12871 		 */
12872 		int sbleft;
12873 		if (sbavail(sb) > sb_offset)
12874 			sbleft = sbavail(sb) - sb_offset;
12875 		else
12876 			sbleft = 0;
12877 		if (sbleft >= min((bbr->r_ctl.rc_high_rwnd/2), bbr->r_ctl.rc_pace_max_segs)) {
12878 			/* not at end of sb lets not send */
12879 			len = 0;
12880 		}
12881 	}
12882 	/*
12883 	 * Decide if we can use TCP Segmentation Offloading (if supported by
12884 	 * hardware).
12885 	 *
12886 	 * TSO may only be used if we are in a pure bulk sending state.  The
12887 	 * presence of TCP-MD5, SACK retransmits, SACK advertizements and IP
12888 	 * options prevent using TSO.  With TSO the TCP header is the same
12889 	 * (except for the sequence number) for all generated packets.  This
12890 	 * makes it impossible to transmit any options which vary per
12891 	 * generated segment or packet.
12892 	 *
12893 	 * IPv4 handling has a clear separation of ip options and ip header
12894 	 * flags while IPv6 combines both in in6p_outputopts. ip6_optlen()
12895 	 * does the right thing below to provide length of just ip options
12896 	 * and thus checking for ipoptlen is enough to decide if ip options
12897 	 * are present.
12898 	 */
12899 #ifdef INET6
12900 	if (isipv6)
12901 		ipoptlen = ip6_optlen(inp);
12902 	else
12903 #endif
12904 	if (inp->inp_options)
12905 		ipoptlen = inp->inp_options->m_len -
12906 		    offsetof(struct ipoption, ipopt_list);
12907 	else
12908 		ipoptlen = 0;
12909 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
12910 	/*
12911 	 * Pre-calculate here as we save another lookup into the darknesses
12912 	 * of IPsec that way and can actually decide if TSO is ok.
12913 	 */
12914 #ifdef INET6
12915 	if (isipv6 && IPSEC_ENABLED(ipv6))
12916 		ipsec_optlen = IPSEC_HDRSIZE(ipv6, inp);
12917 #ifdef INET
12918 	else
12919 #endif
12920 #endif				/* INET6 */
12921 #ifdef INET
12922 	if (IPSEC_ENABLED(ipv4))
12923 		ipsec_optlen = IPSEC_HDRSIZE(ipv4, inp);
12924 #endif				/* INET */
12925 #endif				/* IPSEC */
12926 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
12927 	ipoptlen += ipsec_optlen;
12928 #endif
12929 	if ((tp->t_flags & TF_TSO) && V_tcp_do_tso &&
12930 	    (len > maxseg) &&
12931 	    (tp->t_port == 0) &&
12932 	    ((tp->t_flags & TF_SIGNATURE) == 0) &&
12933 	    tp->rcv_numsacks == 0 &&
12934 	    ipoptlen == 0)
12935 		tso = 1;
12936 
12937 	recwin = min(max(sbspace(&so->so_rcv), 0),
12938 	    TCP_MAXWIN << tp->rcv_scale);
12939 	/*
12940 	 * Sender silly window avoidance.   We transmit under the following
12941 	 * conditions when len is non-zero:
12942 	 *
12943 	 * - We have a full segment (or more with TSO) - This is the last
12944 	 * buffer in a write()/send() and we are either idle or running
12945 	 * NODELAY - we've timed out (e.g. persist timer) - we have more
12946 	 * then 1/2 the maximum send window's worth of data (receiver may be
12947 	 * limited the window size) - we need to retransmit
12948 	 */
12949 	if (rsm)
12950 		goto send;
12951 	if (len) {
12952 		if (sack_rxmit)
12953 			goto send;
12954 		if (len >= p_maxseg)
12955 			goto send;
12956 		/*
12957 		 * NOTE! on localhost connections an 'ack' from the remote
12958 		 * end may occur synchronously with the output and cause us
12959 		 * to flush a buffer queued with moretocome.  XXX
12960 		 *
12961 		 */
12962 		if (((tp->t_flags & TF_MORETOCOME) == 0) &&	/* normal case */
12963 		    ((tp->t_flags & TF_NODELAY) ||
12964 		    ((uint32_t)len + (uint32_t)sb_offset) >= sbavail(&so->so_snd)) &&
12965 		    (tp->t_flags & TF_NOPUSH) == 0) {
12966 			goto send;
12967 		}
12968 		if ((tp->snd_una == tp->snd_max) && len) {	/* Nothing outstanding */
12969 			goto send;
12970 		}
12971 		if (tp->t_flags & TF_FORCEDATA) {	/* typ. timeout case */
12972 			goto send;
12973 		}
12974 		if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) {
12975 			goto send;
12976 		}
12977 	}
12978 	/*
12979 	 * Sending of standalone window updates.
12980 	 *
12981 	 * Window updates are important when we close our window due to a
12982 	 * full socket buffer and are opening it again after the application
12983 	 * reads data from it.  Once the window has opened again and the
12984 	 * remote end starts to send again the ACK clock takes over and
12985 	 * provides the most current window information.
12986 	 *
12987 	 * We must avoid the silly window syndrome whereas every read from
12988 	 * the receive buffer, no matter how small, causes a window update
12989 	 * to be sent.  We also should avoid sending a flurry of window
12990 	 * updates when the socket buffer had queued a lot of data and the
12991 	 * application is doing small reads.
12992 	 *
12993 	 * Prevent a flurry of pointless window updates by only sending an
12994 	 * update when we can increase the advertized window by more than
12995 	 * 1/4th of the socket buffer capacity.  When the buffer is getting
12996 	 * full or is very small be more aggressive and send an update
12997 	 * whenever we can increase by two mss sized segments. In all other
12998 	 * situations the ACK's to new incoming data will carry further
12999 	 * window increases.
13000 	 *
13001 	 * Don't send an independent window update if a delayed ACK is
13002 	 * pending (it will get piggy-backed on it) or the remote side
13003 	 * already has done a half-close and won't send more data.  Skip
13004 	 * this if the connection is in T/TCP half-open state.
13005 	 */
13006 	if (recwin > 0 && !(tp->t_flags & TF_NEEDSYN) &&
13007 	    !(tp->t_flags & TF_DELACK) &&
13008 	    !TCPS_HAVERCVDFIN(tp->t_state)) {
13009 		/* Check to see if we should do a window update */
13010 		if (bbr_window_update_needed(tp, so, recwin, maxseg))
13011 			goto send;
13012 	}
13013 	/*
13014 	 * Send if we owe the peer an ACK, RST, SYN, or urgent data.  ACKNOW
13015 	 * is also a catch-all for the retransmit timer timeout case.
13016 	 */
13017 	if (tp->t_flags & TF_ACKNOW) {
13018 		goto send;
13019 	}
13020 	if (((flags & TH_SYN) && (tp->t_flags & TF_NEEDSYN) == 0)) {
13021 		goto send;
13022 	}
13023 	if (SEQ_GT(tp->snd_up, tp->snd_una)) {
13024 		goto send;
13025 	}
13026 	/*
13027 	 * If our state indicates that FIN should be sent and we have not
13028 	 * yet done so, then we need to send.
13029 	 */
13030 	if (flags & TH_FIN &&
13031 	    ((tp->t_flags & TF_SENTFIN) == 0)) {
13032 		goto send;
13033 	}
13034 	/*
13035 	 * No reason to send a segment, just return.
13036 	 */
13037 just_return:
13038 	SOCKBUF_UNLOCK(sb);
13039 just_return_nolock:
13040 	if (tot_len)
13041 		slot = bbr_get_pacing_delay(bbr, bbr->r_ctl.rc_bbr_hptsi_gain, tot_len, cts, 0);
13042 	if (bbr->rc_no_pacing)
13043 		slot = 0;
13044 	if (tot_len == 0) {
13045 		if ((ctf_outstanding(tp) + min((bbr->r_ctl.rc_high_rwnd/2), bbr_minseg(bbr))) >=
13046 		    tp->snd_wnd) {
13047 			BBR_STAT_INC(bbr_rwnd_limited);
13048 			app_limited = BBR_JR_RWND_LIMITED;
13049 			bbr_cwnd_limiting(tp, bbr, ctf_outstanding(tp));
13050 			if ((bbr->rc_in_persist == 0) &&
13051 			    TCPS_HAVEESTABLISHED(tp->t_state) &&
13052 			    (tp->snd_max == tp->snd_una) &&
13053 			    sbavail(&tp->t_inpcb->inp_socket->so_snd)) {
13054 				/* No send window.. we must enter persist */
13055 				bbr_enter_persist(tp, bbr, bbr->r_ctl.rc_rcvtime, __LINE__);
13056 			}
13057 		} else if (ctf_outstanding(tp) >= sbavail(sb)) {
13058 			BBR_STAT_INC(bbr_app_limited);
13059 			app_limited = BBR_JR_APP_LIMITED;
13060 			bbr_cwnd_limiting(tp, bbr, ctf_outstanding(tp));
13061 		} else if ((ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
13062 						 bbr->r_ctl.rc_lost_bytes)) + p_maxseg) >= tp->snd_cwnd) {
13063 			BBR_STAT_INC(bbr_cwnd_limited);
13064  			app_limited = BBR_JR_CWND_LIMITED;
13065 			bbr_cwnd_limiting(tp, bbr, ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
13066 									bbr->r_ctl.rc_lost_bytes)));
13067 			bbr->rc_cwnd_limited = 1;
13068 		} else {
13069 			BBR_STAT_INC(bbr_app_limited);
13070 			app_limited = BBR_JR_APP_LIMITED;
13071 			bbr_cwnd_limiting(tp, bbr, ctf_outstanding(tp));
13072 		}
13073 		bbr->r_ctl.rc_hptsi_agg_delay = 0;
13074 		bbr->r_agg_early_set = 0;
13075 		bbr->r_ctl.rc_agg_early = 0;
13076 		bbr->r_ctl.rc_last_delay_val = 0;
13077 	} else if (bbr->rc_use_google == 0)
13078 		bbr_check_bbr_for_state(bbr, cts, __LINE__, 0);
13079 	/* Are we app limited? */
13080 	if ((app_limited == BBR_JR_APP_LIMITED) ||
13081 	    (app_limited == BBR_JR_RWND_LIMITED)) {
13082 		/**
13083 		 * We are application limited.
13084 		 */
13085 		bbr->r_ctl.r_app_limited_until = (ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
13086 								       bbr->r_ctl.rc_lost_bytes)) + bbr->r_ctl.rc_delivered);
13087 	}
13088 	if (tot_len == 0)
13089 		counter_u64_add(bbr_out_size[TCP_MSS_ACCT_JUSTRET], 1);
13090 	tp->t_flags &= ~TF_FORCEDATA;
13091 	/* Dont update the time if we did not send */
13092 	bbr->r_ctl.rc_last_delay_val = 0;
13093 	bbr->rc_output_starts_timer = 1;
13094 	bbr_start_hpts_timer(bbr, tp, cts, 9, slot, tot_len);
13095 	bbr_log_type_just_return(bbr, cts, tot_len, hpts_calling, app_limited, p_maxseg, len);
13096 	if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
13097 		/* Make sure snd_nxt is drug up */
13098 		tp->snd_nxt = tp->snd_max;
13099 	}
13100 	return (error);
13101 
13102 send:
13103 	if (doing_tlp == 0) {
13104 		/*
13105 		 * Data not a TLP, and its not the rxt firing. If it is the
13106 		 * rxt firing, we want to leave the tlp_in_progress flag on
13107 		 * so we don't send another TLP. It has to be a rack timer
13108 		 * or normal send (response to acked data) to clear the tlp
13109 		 * in progress flag.
13110 		 */
13111 		bbr->rc_tlp_in_progress = 0;
13112 		bbr->rc_tlp_rtx_out = 0;
13113 	} else {
13114 		/*
13115 		 * Its a TLP.
13116 		 */
13117 		bbr->rc_tlp_in_progress = 1;
13118 	}
13119 	bbr_timer_cancel(bbr, __LINE__, cts);
13120 	if (rsm == NULL) {
13121 		if (sbused(sb) > 0) {
13122 			/*
13123 			 * This is sub-optimal. We only send a stand alone
13124 			 * FIN on its own segment.
13125 			 */
13126 			if (flags & TH_FIN) {
13127 				flags &= ~TH_FIN;
13128 				if ((len == 0) && ((tp->t_flags & TF_ACKNOW) == 0)) {
13129 					/* Lets not send this */
13130 					slot = 0;
13131 					goto just_return;
13132 				}
13133 			}
13134 		}
13135 	} else {
13136 		/*
13137 		 * We do *not* send a FIN on a retransmit if it has data.
13138 		 * The if clause here where len > 1 should never come true.
13139 		 */
13140 		if ((len > 0) &&
13141 		    (((rsm->r_flags & BBR_HAS_FIN) == 0) &&
13142 		    (flags & TH_FIN))) {
13143 			flags &= ~TH_FIN;
13144 			len--;
13145 		}
13146 	}
13147 	SOCKBUF_LOCK_ASSERT(sb);
13148 	if (len > 0) {
13149 		if ((tp->snd_una == tp->snd_max) &&
13150 		    (bbr_calc_time(cts, bbr->r_ctl.rc_went_idle_time) >= bbr_rtt_probe_time)) {
13151 			/*
13152 			 * This qualifies as a RTT_PROBE session since we
13153 			 * drop the data outstanding to nothing and waited
13154 			 * more than bbr_rtt_probe_time.
13155 			 */
13156 			bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_WASIDLE, 0);
13157 			bbr_set_reduced_rtt(bbr, cts, __LINE__);
13158 		}
13159 		if (len >= maxseg)
13160 			tp->t_flags2 |= TF2_PLPMTU_MAXSEGSNT;
13161 		else
13162 			tp->t_flags2 &= ~TF2_PLPMTU_MAXSEGSNT;
13163 	}
13164 	/*
13165 	 * Before ESTABLISHED, force sending of initial options unless TCP
13166 	 * set not to do any options. NOTE: we assume that the IP/TCP header
13167 	 * plus TCP options always fit in a single mbuf, leaving room for a
13168 	 * maximum link header, i.e. max_linkhdr + sizeof (struct tcpiphdr)
13169 	 * + optlen <= MCLBYTES
13170 	 */
13171 	optlen = 0;
13172 #ifdef INET6
13173 	if (isipv6)
13174 		hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
13175 	else
13176 #endif
13177 		hdrlen = sizeof(struct tcpiphdr);
13178 
13179 	/*
13180 	 * Compute options for segment. We only have to care about SYN and
13181 	 * established connection segments.  Options for SYN-ACK segments
13182 	 * are handled in TCP syncache.
13183 	 */
13184 	to.to_flags = 0;
13185 	local_options = 0;
13186 	if ((tp->t_flags & TF_NOOPT) == 0) {
13187 		/* Maximum segment size. */
13188 		if (flags & TH_SYN) {
13189 			to.to_mss = tcp_mssopt(&inp->inp_inc);
13190 #ifdef NETFLIX_TCPOUDP
13191 			if (tp->t_port)
13192 				to.to_mss -= V_tcp_udp_tunneling_overhead;
13193 #endif
13194 			to.to_flags |= TOF_MSS;
13195 			/*
13196 			 * On SYN or SYN|ACK transmits on TFO connections,
13197 			 * only include the TFO option if it is not a
13198 			 * retransmit, as the presence of the TFO option may
13199 			 * have caused the original SYN or SYN|ACK to have
13200 			 * been dropped by a middlebox.
13201 			 */
13202 			if (IS_FASTOPEN(tp->t_flags) &&
13203 			    (tp->t_rxtshift == 0)) {
13204 				if (tp->t_state == TCPS_SYN_RECEIVED) {
13205 					to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN;
13206 					to.to_tfo_cookie =
13207 					    (u_int8_t *)&tp->t_tfo_cookie.server;
13208 					to.to_flags |= TOF_FASTOPEN;
13209 					wanted_cookie = 1;
13210 				} else if (tp->t_state == TCPS_SYN_SENT) {
13211 					to.to_tfo_len =
13212 					    tp->t_tfo_client_cookie_len;
13213 					to.to_tfo_cookie =
13214 					    tp->t_tfo_cookie.client;
13215 					to.to_flags |= TOF_FASTOPEN;
13216 					wanted_cookie = 1;
13217 				}
13218 			}
13219 		}
13220 		/* Window scaling. */
13221 		if ((flags & TH_SYN) && (tp->t_flags & TF_REQ_SCALE)) {
13222 			to.to_wscale = tp->request_r_scale;
13223 			to.to_flags |= TOF_SCALE;
13224 		}
13225 		/* Timestamps. */
13226 		if ((tp->t_flags & TF_RCVD_TSTMP) ||
13227 		    ((flags & TH_SYN) && (tp->t_flags & TF_REQ_TSTMP))) {
13228 			to.to_tsval = 	tcp_tv_to_mssectick(&bbr->rc_tv) + tp->ts_offset;
13229 			to.to_tsecr = tp->ts_recent;
13230 			to.to_flags |= TOF_TS;
13231 			local_options += TCPOLEN_TIMESTAMP + 2;
13232 		}
13233 		/* Set receive buffer autosizing timestamp. */
13234 		if (tp->rfbuf_ts == 0 &&
13235 		    (so->so_rcv.sb_flags & SB_AUTOSIZE))
13236 			tp->rfbuf_ts = 	tcp_tv_to_mssectick(&bbr->rc_tv);
13237 		/* Selective ACK's. */
13238 		if (flags & TH_SYN)
13239 			to.to_flags |= TOF_SACKPERM;
13240 		else if (TCPS_HAVEESTABLISHED(tp->t_state) &&
13241 		    tp->rcv_numsacks > 0) {
13242 			to.to_flags |= TOF_SACK;
13243 			to.to_nsacks = tp->rcv_numsacks;
13244 			to.to_sacks = (u_char *)tp->sackblks;
13245 		}
13246 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
13247 		/* TCP-MD5 (RFC2385). */
13248 		if (tp->t_flags & TF_SIGNATURE)
13249 			to.to_flags |= TOF_SIGNATURE;
13250 #endif				/* TCP_SIGNATURE */
13251 
13252 		/* Processing the options. */
13253 		hdrlen += (optlen = tcp_addoptions(&to, opt));
13254 		/*
13255 		 * If we wanted a TFO option to be added, but it was unable
13256 		 * to fit, ensure no data is sent.
13257 		 */
13258 		if (IS_FASTOPEN(tp->t_flags) && wanted_cookie &&
13259 		    !(to.to_flags & TOF_FASTOPEN))
13260 			len = 0;
13261 	}
13262 #ifdef NETFLIX_TCPOUDP
13263 	if (tp->t_port) {
13264 		if (V_tcp_udp_tunneling_port == 0) {
13265 			/* The port was removed?? */
13266 			SOCKBUF_UNLOCK(&so->so_snd);
13267 			return (EHOSTUNREACH);
13268 		}
13269 		hdrlen += sizeof(struct udphdr);
13270 	}
13271 #endif
13272 #ifdef INET6
13273 	if (isipv6)
13274 		ipoptlen = ip6_optlen(tp->t_inpcb);
13275 	else
13276 #endif
13277 	if (tp->t_inpcb->inp_options)
13278 		ipoptlen = tp->t_inpcb->inp_options->m_len -
13279 		    offsetof(struct ipoption, ipopt_list);
13280 	else
13281 		ipoptlen = 0;
13282 	ipoptlen = 0;
13283 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
13284 	ipoptlen += ipsec_optlen;
13285 #endif
13286 	if (bbr->rc_last_options != local_options) {
13287 		/*
13288 		 * Cache the options length this generally does not change
13289 		 * on a connection. We use this to calculate TSO.
13290 		 */
13291 		bbr->rc_last_options = local_options;
13292 	}
13293 	maxseg = tp->t_maxseg - (ipoptlen + optlen);
13294 	p_maxseg = min(maxseg, pace_max_segs);
13295 	/*
13296 	 * Adjust data length if insertion of options will bump the packet
13297 	 * length beyond the t_maxseg length. Clear the FIN bit because we
13298 	 * cut off the tail of the segment.
13299 	 */
13300 #ifdef KERN_TLS
13301  	/* force TSO for so TLS offload can get mss */
13302  	if (sb->sb_flags & SB_TLS_IFNET) {
13303  		force_tso = 1;
13304  	}
13305 #endif
13306 
13307 	if (len > maxseg) {
13308 		if (len != 0 && (flags & TH_FIN)) {
13309 			flags &= ~TH_FIN;
13310 		}
13311 		if (tso) {
13312 			uint32_t moff;
13313 			int32_t max_len;
13314 
13315 			/* extract TSO information */
13316 			if_hw_tsomax = tp->t_tsomax;
13317 			if_hw_tsomaxsegcount = tp->t_tsomaxsegcount;
13318 			if_hw_tsomaxsegsize = tp->t_tsomaxsegsize;
13319 			KASSERT(ipoptlen == 0,
13320 			    ("%s: TSO can't do IP options", __func__));
13321 
13322 			/*
13323 			 * Check if we should limit by maximum payload
13324 			 * length:
13325 			 */
13326 			if (if_hw_tsomax != 0) {
13327 				/* compute maximum TSO length */
13328 				max_len = (if_hw_tsomax - hdrlen -
13329 				    max_linkhdr);
13330 				if (max_len <= 0) {
13331 					len = 0;
13332 				} else if (len > max_len) {
13333 					len = max_len;
13334 				}
13335 			}
13336 			/*
13337 			 * Prevent the last segment from being fractional
13338 			 * unless the send sockbuf can be emptied:
13339 			 */
13340 			if (((sb_offset + len) < sbavail(sb)) &&
13341 			    (hw_tls == 0)) {
13342 				moff = len % (uint32_t)maxseg;
13343 				if (moff != 0) {
13344 					len -= moff;
13345 				}
13346 			}
13347 			/*
13348 			 * In case there are too many small fragments don't
13349 			 * use TSO:
13350 			 */
13351 			if (len <= maxseg) {
13352 				len = maxseg;
13353 				tso = 0;
13354 			}
13355 		} else {
13356 			/* Not doing TSO */
13357 			if (optlen + ipoptlen >= tp->t_maxseg) {
13358 				/*
13359 				 * Since we don't have enough space to put
13360 				 * the IP header chain and the TCP header in
13361 				 * one packet as required by RFC 7112, don't
13362 				 * send it. Also ensure that at least one
13363 				 * byte of the payload can be put into the
13364 				 * TCP segment.
13365 				 */
13366 				SOCKBUF_UNLOCK(&so->so_snd);
13367 				error = EMSGSIZE;
13368 				sack_rxmit = 0;
13369 				goto out;
13370 			}
13371 			len = maxseg;
13372 		}
13373 	} else {
13374 		/* Not doing TSO */
13375 		if_hw_tsomaxsegcount = 0;
13376 		tso = 0;
13377 	}
13378 	KASSERT(len + hdrlen + ipoptlen <= IP_MAXPACKET,
13379 	    ("%s: len > IP_MAXPACKET", __func__));
13380 #ifdef DIAGNOSTIC
13381 #ifdef INET6
13382 	if (max_linkhdr + hdrlen > MCLBYTES)
13383 #else
13384 	if (max_linkhdr + hdrlen > MHLEN)
13385 #endif
13386 		panic("tcphdr too big");
13387 #endif
13388 	/*
13389 	 * This KASSERT is here to catch edge cases at a well defined place.
13390 	 * Before, those had triggered (random) panic conditions further
13391 	 * down.
13392 	 */
13393 #ifdef BBR_INVARIANTS
13394 	if (sack_rxmit) {
13395 		if (SEQ_LT(rsm->r_start, tp->snd_una)) {
13396 			panic("RSM:%p TP:%p bbr:%p start:%u is < snd_una:%u",
13397 			    rsm, tp, bbr, rsm->r_start, tp->snd_una);
13398 		}
13399 	}
13400 #endif
13401 	KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__));
13402 	if ((len == 0) &&
13403 	    (flags & TH_FIN) &&
13404 	    (sbused(sb))) {
13405 		/*
13406 		 * We have outstanding data, don't send a fin by itself!.
13407 		 */
13408 		slot = 0;
13409 		goto just_return;
13410 	}
13411 	/*
13412 	 * Grab a header mbuf, attaching a copy of data to be transmitted,
13413 	 * and initialize the header from the template for sends on this
13414 	 * connection.
13415 	 */
13416 	if (len) {
13417 		uint32_t moff;
13418 		uint32_t orig_len;
13419 
13420 		/*
13421 		 * We place a limit on sending with hptsi.
13422 		 */
13423 		if ((rsm == NULL) && len > pace_max_segs)
13424 			len = pace_max_segs;
13425 		if (len <= maxseg)
13426 			tso = 0;
13427 #ifdef INET6
13428 		if (MHLEN < hdrlen + max_linkhdr)
13429 			m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
13430 		else
13431 #endif
13432 			m = m_gethdr(M_NOWAIT, MT_DATA);
13433 
13434 		if (m == NULL) {
13435 			BBR_STAT_INC(bbr_failed_mbuf_aloc);
13436 			bbr_log_enobuf_jmp(bbr, len, cts, __LINE__, len, 0, 0);
13437 			SOCKBUF_UNLOCK(sb);
13438 			error = ENOBUFS;
13439 			sack_rxmit = 0;
13440 			goto out;
13441 		}
13442 		m->m_data += max_linkhdr;
13443 		m->m_len = hdrlen;
13444 		/*
13445 		 * Start the m_copy functions from the closest mbuf to the
13446 		 * sb_offset in the socket buffer chain.
13447 		 */
13448 		if ((sb_offset > sbavail(sb)) || ((len + sb_offset) > sbavail(sb))) {
13449 #ifdef BBR_INVARIANTS
13450 			if ((len + sb_offset) > (sbavail(sb) + ((flags & (TH_FIN | TH_SYN)) ? 1 : 0)))
13451 				panic("tp:%p bbr:%p len:%u sb_offset:%u sbavail:%u rsm:%p %u:%u:%u",
13452 				    tp, bbr, len, sb_offset, sbavail(sb), rsm,
13453 				    doing_retran_from,
13454 				    picked_up_retran,
13455 				    doing_tlp);
13456 
13457 #endif
13458 			/*
13459 			 * In this messed up situation we have two choices,
13460 			 * a) pretend the send worked, and just start timers
13461 			 * and what not (not good since that may lead us
13462 			 * back here a lot). <or> b) Send the lowest segment
13463 			 * in the map. <or> c) Drop the connection. Lets do
13464 			 * <b> which if it continues to happen will lead to
13465 			 * <c> via timeouts.
13466 			 */
13467 			BBR_STAT_INC(bbr_offset_recovery);
13468 			rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
13469 			sb_offset = 0;
13470 			if (rsm == NULL) {
13471 				sack_rxmit = 0;
13472 				len = sbavail(sb);
13473 			} else {
13474 				sack_rxmit = 1;
13475 				if (rsm->r_start != tp->snd_una) {
13476 					/*
13477 					 * Things are really messed up, <c>
13478 					 * is the only thing to do.
13479 					 */
13480 					BBR_STAT_INC(bbr_offset_drop);
13481 					tcp_set_inp_to_drop(inp, EFAULT);
13482 					return (0);
13483 				}
13484 				len = rsm->r_end - rsm->r_start;
13485 			}
13486 			if (len > sbavail(sb))
13487 				len = sbavail(sb);
13488 			if (len > maxseg)
13489 				len = maxseg;
13490 		}
13491 		mb = sbsndptr_noadv(sb, sb_offset, &moff);
13492 		if (len <= MHLEN - hdrlen - max_linkhdr && !hw_tls) {
13493 			m_copydata(mb, moff, (int)len,
13494 			    mtod(m, caddr_t)+hdrlen);
13495 			if (rsm == NULL)
13496 				sbsndptr_adv(sb, mb, len);
13497 			m->m_len += len;
13498 		} else {
13499 			struct sockbuf *msb;
13500 
13501 			if (rsm)
13502 				msb = NULL;
13503 			else
13504 				msb = sb;
13505 #ifdef BBR_INVARIANTS
13506 			if ((len + moff) > (sbavail(sb) + ((flags & (TH_FIN | TH_SYN)) ? 1 : 0))) {
13507 				if (rsm) {
13508 					panic("tp:%p bbr:%p len:%u moff:%u sbavail:%u rsm:%p snd_una:%u rsm_start:%u flg:%x %u:%u:%u sr:%d ",
13509 					    tp, bbr, len, moff,
13510 					    sbavail(sb), rsm,
13511 					    tp->snd_una, rsm->r_flags, rsm->r_start,
13512 					    doing_retran_from,
13513 					    picked_up_retran,
13514 					    doing_tlp, sack_rxmit);
13515 				} else {
13516 					panic("tp:%p bbr:%p len:%u moff:%u sbavail:%u sb_offset:%u snd_una:%u",
13517 					    tp, bbr, len, moff, sbavail(sb), sb_offset, tp->snd_una);
13518 				}
13519 			}
13520 #endif
13521 			orig_len = len;
13522 			m->m_next = tcp_m_copym(
13523 #ifdef NETFLIX_COPY_ARGS
13524 				tp,
13525 #endif
13526 				mb, moff, &len,
13527 				if_hw_tsomaxsegcount,
13528 				if_hw_tsomaxsegsize, msb,
13529 				((rsm == NULL) ? hw_tls : 0)
13530 #ifdef NETFLIX_COPY_ARGS
13531 				, &filled_all
13532 #endif
13533 				);
13534 			if (len <= maxseg && !force_tso) {
13535 				/*
13536 				 * Must have ran out of mbufs for the copy
13537 				 * shorten it to no longer need tso. Lets
13538 				 * not put on sendalot since we are low on
13539 				 * mbufs.
13540 				 */
13541 				tso = 0;
13542 			}
13543 			if (m->m_next == NULL) {
13544 				SOCKBUF_UNLOCK(sb);
13545 				(void)m_free(m);
13546 				error = ENOBUFS;
13547 				sack_rxmit = 0;
13548 				goto out;
13549 			}
13550 		}
13551 #ifdef BBR_INVARIANTS
13552 		if (tso && len < maxseg) {
13553 			panic("tp:%p tso on, but len:%d < maxseg:%d",
13554 			    tp, len, maxseg);
13555 		}
13556 		if (tso && if_hw_tsomaxsegcount) {
13557 			int32_t seg_cnt = 0;
13558 			struct mbuf *foo;
13559 
13560 			foo = m;
13561 			while (foo) {
13562 				seg_cnt++;
13563 				foo = foo->m_next;
13564 			}
13565 			if (seg_cnt > if_hw_tsomaxsegcount) {
13566 				panic("seg_cnt:%d > max:%d", seg_cnt, if_hw_tsomaxsegcount);
13567 			}
13568 		}
13569 #endif
13570 		/*
13571 		 * If we're sending everything we've got, set PUSH. (This
13572 		 * will keep happy those implementations which only give
13573 		 * data to the user when a buffer fills or a PUSH comes in.)
13574 		 */
13575 		if (sb_offset + len == sbused(sb) &&
13576 		    sbused(sb) &&
13577 		    !(flags & TH_SYN)) {
13578 			flags |= TH_PUSH;
13579 		}
13580 		SOCKBUF_UNLOCK(sb);
13581 	} else {
13582 		SOCKBUF_UNLOCK(sb);
13583 		if (tp->t_flags & TF_ACKNOW)
13584 			KMOD_TCPSTAT_INC(tcps_sndacks);
13585 		else if (flags & (TH_SYN | TH_FIN | TH_RST))
13586 			KMOD_TCPSTAT_INC(tcps_sndctrl);
13587 		else if (SEQ_GT(tp->snd_up, tp->snd_una))
13588 			KMOD_TCPSTAT_INC(tcps_sndurg);
13589 		else
13590 			KMOD_TCPSTAT_INC(tcps_sndwinup);
13591 
13592 		m = m_gethdr(M_NOWAIT, MT_DATA);
13593 		if (m == NULL) {
13594 			BBR_STAT_INC(bbr_failed_mbuf_aloc);
13595 			bbr_log_enobuf_jmp(bbr, len, cts, __LINE__, len, 0, 0);
13596 			error = ENOBUFS;
13597 			/* Fudge the send time since we could not send */
13598 			sack_rxmit = 0;
13599 			goto out;
13600 		}
13601 #ifdef INET6
13602 		if (isipv6 && (MHLEN < hdrlen + max_linkhdr) &&
13603 		    MHLEN >= hdrlen) {
13604 			M_ALIGN(m, hdrlen);
13605 		} else
13606 #endif
13607 			m->m_data += max_linkhdr;
13608 		m->m_len = hdrlen;
13609 	}
13610 	SOCKBUF_UNLOCK_ASSERT(sb);
13611 	m->m_pkthdr.rcvif = (struct ifnet *)0;
13612 #ifdef MAC
13613 	mac_inpcb_create_mbuf(inp, m);
13614 #endif
13615 #ifdef INET6
13616 	if (isipv6) {
13617 		ip6 = mtod(m, struct ip6_hdr *);
13618 #ifdef NETFLIX_TCPOUDP
13619 		if (tp->t_port) {
13620 			udp = (struct udphdr *)((caddr_t)ip6 + ipoptlen + sizeof(struct ip6_hdr));
13621 			udp->uh_sport = htons(V_tcp_udp_tunneling_port);
13622 			udp->uh_dport = tp->t_port;
13623 			ulen = hdrlen + len - sizeof(struct ip6_hdr);
13624 			udp->uh_ulen = htons(ulen);
13625 			th = (struct tcphdr *)(udp + 1);
13626 		} else {
13627 #endif
13628 			th = (struct tcphdr *)(ip6 + 1);
13629 
13630 #ifdef NETFLIX_TCPOUDP
13631 		}
13632 #endif
13633 		tcpip_fillheaders(inp,
13634 #ifdef NETFLIX_TCPOUDP
13635 				  tp->t_port,
13636 #endif
13637 				  ip6, th);
13638 	} else
13639 #endif				/* INET6 */
13640 	{
13641 		ip = mtod(m, struct ip *);
13642 #ifdef TCPDEBUG
13643 		ipov = (struct ipovly *)ip;
13644 #endif
13645 #ifdef NETFLIX_TCPOUDP
13646 		if (tp->t_port) {
13647 			udp = (struct udphdr *)((caddr_t)ip + ipoptlen + sizeof(struct ip));
13648 			udp->uh_sport = htons(V_tcp_udp_tunneling_port);
13649 			udp->uh_dport = tp->t_port;
13650 			ulen = hdrlen + len - sizeof(struct ip);
13651 			udp->uh_ulen = htons(ulen);
13652 			th = (struct tcphdr *)(udp + 1);
13653 		} else
13654 #endif
13655 			th = (struct tcphdr *)(ip + 1);
13656 		tcpip_fillheaders(inp,
13657 #ifdef NETFLIX_TCPOUDP
13658 				  tp->t_port,
13659 #endif
13660 				  ip, th);
13661 	}
13662 	/*
13663 	 * If we are doing retransmissions, then snd_nxt will not reflect
13664 	 * the first unsent octet.  For ACK only packets, we do not want the
13665 	 * sequence number of the retransmitted packet, we want the sequence
13666 	 * number of the next unsent octet.  So, if there is no data (and no
13667 	 * SYN or FIN), use snd_max instead of snd_nxt when filling in
13668 	 * ti_seq.  But if we are in persist state, snd_max might reflect
13669 	 * one byte beyond the right edge of the window, so use snd_nxt in
13670 	 * that case, since we know we aren't doing a retransmission.
13671 	 * (retransmit and persist are mutually exclusive...)
13672 	 */
13673 	if (sack_rxmit == 0) {
13674 		if (len && ((flags & (TH_FIN | TH_SYN | TH_RST)) == 0)) {
13675 			/* New data (including new persists) */
13676 			th->th_seq = htonl(tp->snd_max);
13677 			bbr_seq = tp->snd_max;
13678 		} else if (flags & TH_SYN) {
13679 			/* Syn's always send from iss */
13680 			th->th_seq = htonl(tp->iss);
13681 			bbr_seq = tp->iss;
13682 		} else if (flags & TH_FIN) {
13683 			if (flags & TH_FIN && tp->t_flags & TF_SENTFIN) {
13684 				/*
13685 				 * If we sent the fin already its 1 minus
13686 				 * snd_max
13687 				 */
13688 				th->th_seq = (htonl(tp->snd_max - 1));
13689 				bbr_seq = (tp->snd_max - 1);
13690 			} else {
13691 				/* First time FIN use snd_max */
13692 				th->th_seq = htonl(tp->snd_max);
13693 				bbr_seq = tp->snd_max;
13694 			}
13695 		} else if (flags & TH_RST) {
13696 			/*
13697 			 * For a Reset send the last cum ack in sequence
13698 			 * (this like any other choice may still generate a
13699 			 * challenge ack, if a ack-update packet is in
13700 			 * flight).
13701 			 */
13702 			th->th_seq = htonl(tp->snd_una);
13703 			bbr_seq = tp->snd_una;
13704 		} else {
13705 			/*
13706 			 * len == 0 and not persist we use snd_max, sending
13707 			 * an ack unless we have sent the fin then its 1
13708 			 * minus.
13709 			 */
13710 			/*
13711 			 * XXXRRS Question if we are in persists and we have
13712 			 * nothing outstanding to send and we have not sent
13713 			 * a FIN, we will send an ACK. In such a case it
13714 			 * might be better to send (tp->snd_una - 1) which
13715 			 * would force the peer to ack.
13716 			 */
13717 			if (tp->t_flags & TF_SENTFIN) {
13718 				th->th_seq = htonl(tp->snd_max - 1);
13719 				bbr_seq = (tp->snd_max - 1);
13720 			} else {
13721 				th->th_seq = htonl(tp->snd_max);
13722 				bbr_seq = tp->snd_max;
13723 			}
13724 		}
13725 	} else {
13726 		/* All retransmits use the rsm to guide the send */
13727 		th->th_seq = htonl(rsm->r_start);
13728 		bbr_seq = rsm->r_start;
13729 	}
13730 	th->th_ack = htonl(tp->rcv_nxt);
13731 	if (optlen) {
13732 		bcopy(opt, th + 1, optlen);
13733 		th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
13734 	}
13735 	th->th_flags = flags;
13736 	/*
13737 	 * Calculate receive window.  Don't shrink window, but avoid silly
13738 	 * window syndrome.
13739 	 */
13740 	if ((flags & TH_RST) || ((recwin < (so->so_rcv.sb_hiwat / 4) &&
13741 				  recwin < maxseg)))
13742 		recwin = 0;
13743 	if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt) &&
13744 	    recwin < (tp->rcv_adv - tp->rcv_nxt))
13745 		recwin = (tp->rcv_adv - tp->rcv_nxt);
13746 	if (recwin > TCP_MAXWIN << tp->rcv_scale)
13747 		recwin = TCP_MAXWIN << tp->rcv_scale;
13748 
13749 	/*
13750 	 * According to RFC1323 the window field in a SYN (i.e., a <SYN> or
13751 	 * <SYN,ACK>) segment itself is never scaled.  The <SYN,ACK> case is
13752 	 * handled in syncache.
13753 	 */
13754 	if (flags & TH_SYN)
13755 		th->th_win = htons((u_short)
13756 		    (min(sbspace(&so->so_rcv), TCP_MAXWIN)));
13757 	else
13758 		th->th_win = htons((u_short)(recwin >> tp->rcv_scale));
13759 	/*
13760 	 * Adjust the RXWIN0SENT flag - indicate that we have advertised a 0
13761 	 * window.  This may cause the remote transmitter to stall.  This
13762 	 * flag tells soreceive() to disable delayed acknowledgements when
13763 	 * draining the buffer.  This can occur if the receiver is
13764 	 * attempting to read more data than can be buffered prior to
13765 	 * transmitting on the connection.
13766 	 */
13767 	if (th->th_win == 0) {
13768 		tp->t_sndzerowin++;
13769 		tp->t_flags |= TF_RXWIN0SENT;
13770 	} else
13771 		tp->t_flags &= ~TF_RXWIN0SENT;
13772 	if (SEQ_GT(tp->snd_up, tp->snd_max)) {
13773 		th->th_urp = htons((u_short)(tp->snd_up - tp->snd_max));
13774 		th->th_flags |= TH_URG;
13775 	} else
13776 		/*
13777 		 * If no urgent pointer to send, then we pull the urgent
13778 		 * pointer to the left edge of the send window so that it
13779 		 * doesn't drift into the send window on sequence number
13780 		 * wraparound.
13781 		 */
13782 		tp->snd_up = tp->snd_una;	/* drag it along */
13783 
13784 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
13785 	if (to.to_flags & TOF_SIGNATURE) {
13786 		/*
13787 		 * Calculate MD5 signature and put it into the place
13788 		 * determined before. NOTE: since TCP options buffer doesn't
13789 		 * point into mbuf's data, calculate offset and use it.
13790 		 */
13791 		if (!TCPMD5_ENABLED() || TCPMD5_OUTPUT(m, th,
13792 		    (u_char *)(th + 1) + (to.to_signature - opt)) != 0) {
13793 			/*
13794 			 * Do not send segment if the calculation of MD5
13795 			 * digest has failed.
13796 			 */
13797 			goto out;
13798 		}
13799 	}
13800 #endif
13801 
13802 	/*
13803 	 * Put TCP length in extended header, and then checksum extended
13804 	 * header and data.
13805 	 */
13806 	m->m_pkthdr.len = hdrlen + len;	/* in6_cksum() need this */
13807 #ifdef INET6
13808 	if (isipv6) {
13809 		/*
13810 		 * ip6_plen is not need to be filled now, and will be filled
13811 		 * in ip6_output.
13812 		 */
13813 #ifdef NETFLIX_TCPOUDP
13814 		if (tp->t_port) {
13815 			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
13816 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
13817 			udp->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0);
13818 			th->th_sum = htons(0);
13819 			UDPSTAT_INC(udps_opackets);
13820 		} else {
13821 #endif
13822 			csum_flags = m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
13823 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
13824 			th->th_sum = in6_cksum_pseudo(ip6, sizeof(struct tcphdr) +
13825 			    optlen + len, IPPROTO_TCP, 0);
13826 #ifdef NETFLIX_TCPOUDP
13827 		}
13828 #endif
13829 	}
13830 #endif
13831 #if defined(INET6) && defined(INET)
13832 	else
13833 #endif
13834 #ifdef INET
13835 	{
13836 #ifdef NETFLIX_TCPOUDP
13837 		if (tp->t_port) {
13838 			m->m_pkthdr.csum_flags = CSUM_UDP;
13839 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
13840 			udp->uh_sum = in_pseudo(ip->ip_src.s_addr,
13841 			    ip->ip_dst.s_addr, htons(ulen + IPPROTO_UDP));
13842 			th->th_sum = htons(0);
13843 			UDPSTAT_INC(udps_opackets);
13844 		} else {
13845 #endif
13846 			csum_flags = m->m_pkthdr.csum_flags = CSUM_TCP;
13847 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
13848 			th->th_sum = in_pseudo(ip->ip_src.s_addr,
13849 			    ip->ip_dst.s_addr, htons(sizeof(struct tcphdr) +
13850 			    IPPROTO_TCP + len + optlen));
13851 #ifdef NETFLIX_TCPOUDP
13852 		}
13853 #endif
13854 		/* IP version must be set here for ipv4/ipv6 checking later */
13855 		KASSERT(ip->ip_v == IPVERSION,
13856 		    ("%s: IP version incorrect: %d", __func__, ip->ip_v));
13857 	}
13858 #endif
13859 
13860 	/*
13861 	 * Enable TSO and specify the size of the segments. The TCP pseudo
13862 	 * header checksum is always provided. XXX: Fixme: This is currently
13863 	 * not the case for IPv6.
13864 	 */
13865 	if (tso || force_tso) {
13866 		KASSERT(force_tso || len > maxseg,
13867 		    ("%s: len:%d <= tso_segsz:%d", __func__, len, maxseg));
13868 		m->m_pkthdr.csum_flags |= CSUM_TSO;
13869 		csum_flags |= CSUM_TSO;
13870 		m->m_pkthdr.tso_segsz = maxseg;
13871 	}
13872 	KASSERT(len + hdrlen == m_length(m, NULL),
13873 	    ("%s: mbuf chain different than expected: %d + %u != %u",
13874 	    __func__, len, hdrlen, m_length(m, NULL)));
13875 
13876 #ifdef TCP_HHOOK
13877 	/* Run HHOOK_TC_ESTABLISHED_OUT helper hooks. */
13878 	hhook_run_tcp_est_out(tp, th, &to, len, tso);
13879 #endif
13880 #ifdef TCPDEBUG
13881 	/*
13882 	 * Trace.
13883 	 */
13884 	if (so->so_options & SO_DEBUG) {
13885 		u_short save = 0;
13886 
13887 #ifdef INET6
13888 		if (!isipv6)
13889 #endif
13890 		{
13891 			save = ipov->ih_len;
13892 			ipov->ih_len = htons(m->m_pkthdr.len	/* - hdrlen +
13893 			      * (th->th_off << 2) */ );
13894 		}
13895 		tcp_trace(TA_OUTPUT, tp->t_state, tp, mtod(m, void *), th, 0);
13896 #ifdef INET6
13897 		if (!isipv6)
13898 #endif
13899 			ipov->ih_len = save;
13900 	}
13901 #endif				/* TCPDEBUG */
13902 
13903 	/* Log to the black box */
13904 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
13905 		union tcp_log_stackspecific log;
13906 
13907 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
13908 		/* Record info on type of transmission */
13909 		log.u_bbr.flex1 = bbr->r_ctl.rc_hptsi_agg_delay;
13910 		log.u_bbr.flex2 = (bbr->r_recovery_bw << 3);
13911 		log.u_bbr.flex3 = maxseg;
13912 		log.u_bbr.flex4 = delay_calc;
13913 		/* Encode filled_all into the upper flex5 bit */
13914 		log.u_bbr.flex5 = bbr->rc_past_init_win;
13915 		log.u_bbr.flex5 <<= 1;
13916 		log.u_bbr.flex5 |= bbr->rc_no_pacing;
13917 		log.u_bbr.flex5 <<= 29;
13918 		if (filled_all)
13919 			log.u_bbr.flex5 |= 0x80000000;
13920 		log.u_bbr.flex5 |= tp->t_maxseg;
13921 		log.u_bbr.flex6 = bbr->r_ctl.rc_pace_max_segs;
13922 		log.u_bbr.flex7 = (bbr->rc_bbr_state << 8) | bbr_state_val(bbr);
13923 		/* lets poke in the low and the high here for debugging */
13924 		log.u_bbr.pkts_out = bbr->rc_tp->t_maxseg;
13925 		if (rsm || sack_rxmit) {
13926 			if (doing_tlp)
13927 				log.u_bbr.flex8 = 2;
13928 			else
13929 				log.u_bbr.flex8 = 1;
13930 		} else {
13931 			log.u_bbr.flex8 = 0;
13932 		}
13933 		lgb = tcp_log_event_(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_OUT, ERRNO_UNK,
13934 		    len, &log, false, NULL, NULL, 0, tv);
13935 	} else {
13936 		lgb = NULL;
13937 	}
13938 	/*
13939 	 * Fill in IP length and desired time to live and send to IP level.
13940 	 * There should be a better way to handle ttl and tos; we could keep
13941 	 * them in the template, but need a way to checksum without them.
13942 	 */
13943 	/*
13944 	 * m->m_pkthdr.len should have been set before cksum calcuration,
13945 	 * because in6_cksum() need it.
13946 	 */
13947 #ifdef INET6
13948 	if (isipv6) {
13949 		/*
13950 		 * we separately set hoplimit for every segment, since the
13951 		 * user might want to change the value via setsockopt. Also,
13952 		 * desired default hop limit might be changed via Neighbor
13953 		 * Discovery.
13954 		 */
13955 		ip6->ip6_hlim = in6_selecthlim(inp, NULL);
13956 
13957 		/*
13958 		 * Set the packet size here for the benefit of DTrace
13959 		 * probes. ip6_output() will set it properly; it's supposed
13960 		 * to include the option header lengths as well.
13961 		 */
13962 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
13963 
13964 		if (V_path_mtu_discovery && maxseg > V_tcp_minmss)
13965 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
13966 		else
13967 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
13968 
13969 		if (tp->t_state == TCPS_SYN_SENT)
13970 			TCP_PROBE5(connect__request, NULL, tp, ip6, tp, th);
13971 
13972 		TCP_PROBE5(send, NULL, tp, ip6, tp, th);
13973 		/* TODO: IPv6 IP6TOS_ECT bit on */
13974 		error = ip6_output(m, inp->in6p_outputopts,
13975 		    &inp->inp_route6,
13976 		    ((rsm || sack_rxmit) ? IP_NO_SND_TAG_RL : 0),
13977 		    NULL, NULL, inp);
13978 
13979 		if (error == EMSGSIZE && inp->inp_route6.ro_nh != NULL)
13980 			mtu = inp->inp_route6.ro_nh->nh_mtu;
13981 	}
13982 #endif				/* INET6 */
13983 #if defined(INET) && defined(INET6)
13984 	else
13985 #endif
13986 #ifdef INET
13987 	{
13988 		ip->ip_len = htons(m->m_pkthdr.len);
13989 #ifdef INET6
13990 		if (isipv6)
13991 			ip->ip_ttl = in6_selecthlim(inp, NULL);
13992 #endif				/* INET6 */
13993 		/*
13994 		 * If we do path MTU discovery, then we set DF on every
13995 		 * packet. This might not be the best thing to do according
13996 		 * to RFC3390 Section 2. However the tcp hostcache migitates
13997 		 * the problem so it affects only the first tcp connection
13998 		 * with a host.
13999 		 *
14000 		 * NB: Don't set DF on small MTU/MSS to have a safe
14001 		 * fallback.
14002 		 */
14003 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) {
14004 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
14005 			if (tp->t_port == 0 || len < V_tcp_minmss) {
14006 				ip->ip_off |= htons(IP_DF);
14007 			}
14008 		} else {
14009 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
14010 		}
14011 
14012 		if (tp->t_state == TCPS_SYN_SENT)
14013 			TCP_PROBE5(connect__request, NULL, tp, ip, tp, th);
14014 
14015 		TCP_PROBE5(send, NULL, tp, ip, tp, th);
14016 
14017 		error = ip_output(m, inp->inp_options, &inp->inp_route,
14018 		    ((rsm || sack_rxmit) ? IP_NO_SND_TAG_RL : 0), 0,
14019 		    inp);
14020 		if (error == EMSGSIZE && inp->inp_route.ro_nh != NULL)
14021 			mtu = inp->inp_route.ro_nh->nh_mtu;
14022 	}
14023 #endif				/* INET */
14024 out:
14025 
14026 	if (lgb) {
14027 		lgb->tlb_errno = error;
14028 		lgb = NULL;
14029 	}
14030 	/*
14031 	 * In transmit state, time the transmission and arrange for the
14032 	 * retransmit.  In persist state, just set snd_max.
14033 	 */
14034 	if (error == 0) {
14035 		if (TCPS_HAVEESTABLISHED(tp->t_state) &&
14036 		    (tp->t_flags & TF_SACK_PERMIT) &&
14037 		    tp->rcv_numsacks > 0)
14038 			tcp_clean_dsack_blocks(tp);
14039 		/* We sent an ack clear the bbr_segs_rcvd count */
14040 		bbr->output_error_seen = 0;
14041 		bbr->oerror_cnt = 0;
14042 		bbr->bbr_segs_rcvd = 0;
14043 		if (len == 0)
14044 			counter_u64_add(bbr_out_size[TCP_MSS_ACCT_SNDACK], 1);
14045 		else if (hw_tls) {
14046 			if (filled_all ||
14047 			    (len >= bbr->r_ctl.rc_pace_max_segs))
14048 				BBR_STAT_INC(bbr_meets_tso_thresh);
14049 			else {
14050 				if (doing_tlp) {
14051 					BBR_STAT_INC(bbr_miss_tlp);
14052 					bbr_log_type_hrdwtso(tp, bbr, len, 1, what_we_can);
14053 
14054 
14055 				} else if (rsm) {
14056 					BBR_STAT_INC(bbr_miss_retran);
14057 					bbr_log_type_hrdwtso(tp, bbr, len, 2, what_we_can);
14058 				} else if ((ctf_outstanding(tp) + bbr->r_ctl.rc_pace_max_segs) > sbavail(sb)) {
14059 					BBR_STAT_INC(bbr_miss_tso_app);
14060 					bbr_log_type_hrdwtso(tp, bbr, len, 3, what_we_can);
14061 				} else if ((ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
14062 								 bbr->r_ctl.rc_lost_bytes)) + bbr->r_ctl.rc_pace_max_segs) > tp->snd_cwnd) {
14063 					BBR_STAT_INC(bbr_miss_tso_cwnd);
14064 					bbr_log_type_hrdwtso(tp, bbr, len, 4, what_we_can);
14065 				} else if ((ctf_outstanding(tp) + bbr->r_ctl.rc_pace_max_segs) > tp->snd_wnd) {
14066 					BBR_STAT_INC(bbr_miss_tso_rwnd);
14067 					bbr_log_type_hrdwtso(tp, bbr, len, 5, what_we_can);
14068 				} else {
14069 					BBR_STAT_INC(bbr_miss_unknown);
14070 					bbr_log_type_hrdwtso(tp, bbr, len, 6, what_we_can);
14071 				}
14072 			}
14073 		}
14074 		/* Do accounting for new sends */
14075 		if ((len > 0) && (rsm == NULL)) {
14076 			int idx;
14077 			if (tp->snd_una == tp->snd_max) {
14078 				/*
14079 				 * Special case to match google, when
14080 				 * nothing is in flight the delivered
14081 				 * time does get updated to the current
14082 				 * time (see tcp_rate_bsd.c).
14083 				 */
14084 				bbr->r_ctl.rc_del_time = cts;
14085 			}
14086 			if (len >= maxseg) {
14087 				idx = (len / maxseg) + 3;
14088 				if (idx >= TCP_MSS_ACCT_ATIMER)
14089 					counter_u64_add(bbr_out_size[(TCP_MSS_ACCT_ATIMER - 1)], 1);
14090 				else
14091 					counter_u64_add(bbr_out_size[idx], 1);
14092 			} else {
14093 				/* smaller than a MSS */
14094 				idx = len / (bbr_hptsi_bytes_min - bbr->rc_last_options);
14095 				if (idx >= TCP_MSS_SMALL_MAX_SIZE_DIV)
14096 					idx = (TCP_MSS_SMALL_MAX_SIZE_DIV - 1);
14097 				counter_u64_add(bbr_out_size[(idx + TCP_MSS_SMALL_SIZE_OFF)], 1);
14098 			}
14099 		}
14100 	}
14101 	abandon = 0;
14102 	/*
14103 	 * We must do the send accounting before we log the output,
14104 	 * otherwise the state of the rsm could change and we account to the
14105 	 * wrong bucket.
14106 	 */
14107 	if (len > 0) {
14108 		bbr_do_send_accounting(tp, bbr, rsm, len, error);
14109 		if (error == 0) {
14110 			if (tp->snd_una == tp->snd_max)
14111 				bbr->r_ctl.rc_tlp_rxt_last_time = cts;
14112 		}
14113 	}
14114 	bbr_log_output(bbr, tp, &to, len, bbr_seq, (uint8_t) flags, error,
14115 	    cts, mb, &abandon, rsm, 0, sb);
14116 	if (abandon) {
14117 		/*
14118 		 * If bbr_log_output destroys the TCB or sees a TH_RST being
14119 		 * sent we should hit this condition.
14120 		 */
14121 		return (0);
14122 	}
14123 	if (((tp->t_flags & TF_FORCEDATA) == 0) ||
14124 	    (bbr->rc_in_persist == 0)) {
14125 		/*
14126 		 * Advance snd_nxt over sequence space of this segment.
14127 		 */
14128 		if (error)
14129 			/* We don't log or do anything with errors */
14130 			goto skip_upd;
14131 
14132 		if (tp->snd_una == tp->snd_max &&
14133 		    (len || (flags & (TH_SYN | TH_FIN)))) {
14134 			/*
14135 			 * Update the time we just added data since none was
14136 			 * outstanding.
14137 			 */
14138 			bbr_log_progress_event(bbr, tp, ticks, PROGRESS_START, __LINE__);
14139 			bbr->rc_tp->t_acktime  = ticks;
14140 		}
14141 		if (flags & (TH_SYN | TH_FIN) && (rsm == NULL)) {
14142 			if (flags & TH_SYN) {
14143 				tp->snd_max++;
14144 			}
14145 			if ((flags & TH_FIN) && ((tp->t_flags & TF_SENTFIN) == 0)) {
14146 				tp->snd_max++;
14147 				tp->t_flags |= TF_SENTFIN;
14148 			}
14149 		}
14150 		if (sack_rxmit == 0)
14151 			tp->snd_max += len;
14152 skip_upd:
14153 		if ((error == 0) && len)
14154 			tot_len += len;
14155 	} else {
14156 		/* Persists case */
14157 		int32_t xlen = len;
14158 
14159 		if (error)
14160 			goto nomore;
14161 
14162 		if (flags & TH_SYN)
14163 			++xlen;
14164 		if ((flags & TH_FIN) && ((tp->t_flags & TF_SENTFIN) == 0)) {
14165 			++xlen;
14166 			tp->t_flags |= TF_SENTFIN;
14167 		}
14168 		if (xlen && (tp->snd_una == tp->snd_max)) {
14169 			/*
14170 			 * Update the time we just added data since none was
14171 			 * outstanding.
14172 			 */
14173 			bbr_log_progress_event(bbr, tp, ticks, PROGRESS_START, __LINE__);
14174 			bbr->rc_tp->t_acktime = ticks;
14175 		}
14176 		if (sack_rxmit == 0)
14177 			tp->snd_max += xlen;
14178 		tot_len += (len + optlen + ipoptlen);
14179 	}
14180 nomore:
14181 	if (error) {
14182 		/*
14183 		 * Failures do not advance the seq counter above. For the
14184 		 * case of ENOBUFS we will fall out and become ack-clocked.
14185 		 * capping the cwnd at the current flight.
14186 		 * Everything else will just have to retransmit with the timer
14187 		 * (no pacer).
14188 		 */
14189 		SOCKBUF_UNLOCK_ASSERT(sb);
14190 		BBR_STAT_INC(bbr_saw_oerr);
14191 		/* Clear all delay/early tracks */
14192 		bbr->r_ctl.rc_hptsi_agg_delay = 0;
14193 		bbr->r_ctl.rc_agg_early = 0;
14194 		bbr->r_agg_early_set = 0;
14195 		bbr->output_error_seen = 1;
14196 		if (bbr->oerror_cnt < 0xf)
14197 			bbr->oerror_cnt++;
14198 		if (bbr_max_net_error_cnt && (bbr->oerror_cnt >= bbr_max_net_error_cnt)) {
14199 			/* drop the session */
14200 			tcp_set_inp_to_drop(inp, ENETDOWN);
14201 		}
14202 		switch (error) {
14203 		case ENOBUFS:
14204 			/*
14205 			 * Make this guy have to get ack's to send
14206 			 * more but lets make sure we don't
14207 			 * slam him below a T-O (1MSS).
14208 			 */
14209 			if (bbr->rc_bbr_state != BBR_STATE_PROBE_RTT) {
14210 				tp->snd_cwnd = ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
14211 								    bbr->r_ctl.rc_lost_bytes)) - maxseg;
14212 				if (tp->snd_cwnd < maxseg)
14213 					tp->snd_cwnd = maxseg;
14214 			}
14215 			slot = (bbr_error_base_paceout + 1) << bbr->oerror_cnt;
14216 			BBR_STAT_INC(bbr_saw_enobuf);
14217 			if (bbr->bbr_hdrw_pacing)
14218 				counter_u64_add(bbr_hdwr_pacing_enobuf, 1);
14219 			else
14220 				counter_u64_add(bbr_nohdwr_pacing_enobuf, 1);
14221 			/*
14222 			 * Here even in the enobuf's case we want to do our
14223 			 * state update. The reason being we may have been
14224 			 * called by the input function. If so we have had
14225 			 * things change.
14226 			 */
14227 			error = 0;
14228 			goto enobufs;
14229 		case EMSGSIZE:
14230 			/*
14231 			 * For some reason the interface we used initially
14232 			 * to send segments changed to another or lowered
14233 			 * its MTU. If TSO was active we either got an
14234 			 * interface without TSO capabilits or TSO was
14235 			 * turned off. If we obtained mtu from ip_output()
14236 			 * then update it and try again.
14237 			 */
14238 			/* Turn on tracing (or try to) */
14239 			{
14240 				int old_maxseg;
14241 
14242 				old_maxseg = tp->t_maxseg;
14243 				BBR_STAT_INC(bbr_saw_emsgsiz);
14244 				bbr_log_msgsize_fail(bbr, tp, len, maxseg, mtu, csum_flags, tso, cts);
14245 				if (mtu != 0)
14246 					tcp_mss_update(tp, -1, mtu, NULL, NULL);
14247 				if (old_maxseg <= tp->t_maxseg) {
14248 					/* Huh it did not shrink? */
14249 					tp->t_maxseg = old_maxseg - 40;
14250 					bbr_log_msgsize_fail(bbr, tp, len, maxseg, mtu, 0, tso, cts);
14251 				}
14252 				tp->t_flags &= ~TF_FORCEDATA;
14253 				/*
14254 				 * Nuke all other things that can interfere
14255 				 * with slot
14256 				 */
14257 				if ((tot_len + len) && (len >= tp->t_maxseg)) {
14258 					slot = bbr_get_pacing_delay(bbr,
14259 					    bbr->r_ctl.rc_bbr_hptsi_gain,
14260 					    (tot_len + len), cts, 0);
14261 					if (slot < bbr_error_base_paceout)
14262 						slot = (bbr_error_base_paceout + 2) << bbr->oerror_cnt;
14263 				} else
14264 					slot = (bbr_error_base_paceout + 2) << bbr->oerror_cnt;
14265 				bbr->rc_output_starts_timer = 1;
14266 				bbr_start_hpts_timer(bbr, tp, cts, 10, slot,
14267 				    tot_len);
14268 				return (error);
14269 			}
14270 		case EPERM:
14271 			tp->t_softerror = error;
14272 			/* Fall through */
14273 		case EHOSTDOWN:
14274 		case EHOSTUNREACH:
14275 		case ENETDOWN:
14276 		case ENETUNREACH:
14277 			if (TCPS_HAVERCVDSYN(tp->t_state)) {
14278 				tp->t_softerror = error;
14279 			}
14280 			/* FALLTHROUGH */
14281 		default:
14282 			tp->t_flags &= ~TF_FORCEDATA;
14283 			slot = (bbr_error_base_paceout + 3) << bbr->oerror_cnt;
14284 			bbr->rc_output_starts_timer = 1;
14285 			bbr_start_hpts_timer(bbr, tp, cts, 11, slot, 0);
14286 			return (error);
14287 		}
14288 #ifdef STATS
14289 	} else if (((tp->t_flags & TF_GPUTINPROG) == 0) &&
14290 		    len &&
14291 		    (rsm == NULL) &&
14292 	    (bbr->rc_in_persist == 0)) {
14293 		tp->gput_seq = bbr_seq;
14294 		tp->gput_ack = bbr_seq +
14295 		    min(sbavail(&so->so_snd) - sb_offset, sendwin);
14296 		tp->gput_ts = cts;
14297 		tp->t_flags |= TF_GPUTINPROG;
14298 #endif
14299 	}
14300 	KMOD_TCPSTAT_INC(tcps_sndtotal);
14301 	if ((bbr->bbr_hdw_pace_ena) &&
14302 	    (bbr->bbr_attempt_hdwr_pace == 0) &&
14303 	    (bbr->rc_past_init_win) &&
14304 	    (bbr->rc_bbr_state != BBR_STATE_STARTUP) &&
14305 	    (get_filter_value(&bbr->r_ctl.rc_delrate)) &&
14306 	    (inp->inp_route.ro_nh &&
14307 	     inp->inp_route.ro_nh->nh_ifp)) {
14308 		/*
14309 		 * We are past the initial window and
14310 		 * have at least one measurement so we
14311 		 * could use hardware pacing if its available.
14312 		 * We have an interface and we have not attempted
14313 		 * to setup hardware pacing, lets try to now.
14314 		 */
14315 		uint64_t rate_wanted;
14316 		int err = 0;
14317 
14318 		rate_wanted = bbr_get_hardware_rate(bbr);
14319 		bbr->bbr_attempt_hdwr_pace = 1;
14320 		bbr->r_ctl.crte = tcp_set_pacing_rate(bbr->rc_tp,
14321 						      inp->inp_route.ro_nh->nh_ifp,
14322 						      rate_wanted,
14323 						      (RS_PACING_GEQ|RS_PACING_SUB_OK),
14324 						      &err);
14325 		if (bbr->r_ctl.crte) {
14326 			bbr_type_log_hdwr_pacing(bbr,
14327 						 bbr->r_ctl.crte->ptbl->rs_ifp,
14328 						 rate_wanted,
14329 						 bbr->r_ctl.crte->rate,
14330 						 __LINE__, cts, err);
14331 			BBR_STAT_INC(bbr_hdwr_rl_add_ok);
14332 			counter_u64_add(bbr_flows_nohdwr_pacing, -1);
14333 			counter_u64_add(bbr_flows_whdwr_pacing, 1);
14334 			bbr->bbr_hdrw_pacing = 1;
14335 			/* Now what is our gain status? */
14336 			if (bbr->r_ctl.crte->rate < rate_wanted) {
14337 				/* We have a problem */
14338 				bbr_setup_less_of_rate(bbr, cts,
14339 						       bbr->r_ctl.crte->rate, rate_wanted);
14340 			} else {
14341 				/* We are good */
14342 				bbr->gain_is_limited = 0;
14343 				bbr->skip_gain = 0;
14344 			}
14345 			tcp_bbr_tso_size_check(bbr, cts);
14346 		} else {
14347 			bbr_type_log_hdwr_pacing(bbr,
14348 						 inp->inp_route.ro_nh->nh_ifp,
14349 						 rate_wanted,
14350 						 0,
14351 						 __LINE__, cts, err);
14352 			BBR_STAT_INC(bbr_hdwr_rl_add_fail);
14353 		}
14354 	}
14355 	if (bbr->bbr_hdrw_pacing) {
14356 		/*
14357 		 * Worry about cases where the route
14358 		 * changes or something happened that we
14359 		 * lost our hardware pacing possibly during
14360 		 * the last ip_output call.
14361 		 */
14362 		if (inp->inp_snd_tag == NULL) {
14363 			/* A change during ip output disabled hw pacing? */
14364 			bbr->bbr_hdrw_pacing = 0;
14365 		} else if ((inp->inp_route.ro_nh == NULL) ||
14366 		    (inp->inp_route.ro_nh->nh_ifp != inp->inp_snd_tag->ifp)) {
14367 			/*
14368 			 * We had an interface or route change,
14369 			 * detach from the current hdwr pacing
14370 			 * and setup to re-attempt next go
14371 			 * round.
14372 			 */
14373 			bbr->bbr_hdrw_pacing = 0;
14374 			bbr->bbr_attempt_hdwr_pace = 0;
14375 			tcp_rel_pacing_rate(bbr->r_ctl.crte, bbr->rc_tp);
14376 			tcp_bbr_tso_size_check(bbr, cts);
14377 		}
14378 	}
14379 	/*
14380 	 * Data sent (as far as we can tell). If this advertises a larger
14381 	 * window than any other segment, then remember the size of the
14382 	 * advertised window. Any pending ACK has now been sent.
14383 	 */
14384 	if (SEQ_GT(tp->rcv_nxt + recwin, tp->rcv_adv))
14385 		tp->rcv_adv = tp->rcv_nxt + recwin;
14386 
14387 	tp->last_ack_sent = tp->rcv_nxt;
14388 	if ((error == 0) &&
14389 	    (bbr->r_ctl.rc_pace_max_segs > tp->t_maxseg) &&
14390 	    (doing_tlp == 0) &&
14391 	    (tso == 0) &&
14392 	    (hw_tls == 0) &&
14393 	    (len > 0) &&
14394 	    ((flags & TH_RST) == 0) &&
14395 	    (IN_RECOVERY(tp->t_flags) == 0) &&
14396 	    (bbr->rc_in_persist == 0) &&
14397 	    ((tp->t_flags & TF_FORCEDATA) == 0) &&
14398 	    (tot_len < bbr->r_ctl.rc_pace_max_segs)) {
14399 		/*
14400 		 * For non-tso we need to goto again until we have sent out
14401 		 * enough data to match what we are hptsi out every hptsi
14402 		 * interval.
14403 		 */
14404 		if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
14405 			/* Make sure snd_nxt is drug up */
14406 			tp->snd_nxt = tp->snd_max;
14407 		}
14408 		if (rsm != NULL) {
14409 			rsm = NULL;
14410 			goto skip_again;
14411 		}
14412 		rsm = NULL;
14413 		sack_rxmit = 0;
14414 		tp->t_flags &= ~(TF_ACKNOW | TF_DELACK | TF_FORCEDATA);
14415 		goto again;
14416 	}
14417 skip_again:
14418 	if (((flags & (TH_RST | TH_SYN | TH_FIN)) == 0) && tot_len) {
14419 		/*
14420 		 * Calculate/Re-Calculate the hptsi slot in usecs based on
14421 		 * what we have sent so far
14422 		 */
14423 		slot = bbr_get_pacing_delay(bbr, bbr->r_ctl.rc_bbr_hptsi_gain, tot_len, cts, 0);
14424 		if (bbr->rc_no_pacing)
14425 			slot = 0;
14426 	}
14427 	tp->t_flags &= ~(TF_ACKNOW | TF_DELACK | TF_FORCEDATA);
14428 enobufs:
14429 	if (bbr->rc_use_google == 0)
14430 		bbr_check_bbr_for_state(bbr, cts, __LINE__, 0);
14431 	bbr_cwnd_limiting(tp, bbr, ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
14432 							bbr->r_ctl.rc_lost_bytes)));
14433 	bbr->rc_output_starts_timer = 1;
14434 	if (bbr->bbr_use_rack_cheat &&
14435 	    (more_to_rxt ||
14436 	     ((bbr->r_ctl.rc_resend = bbr_check_recovery_mode(tp, bbr, cts)) != NULL))) {
14437 		/* Rack cheats and shotguns out all rxt's 1ms apart */
14438 		if (slot > 1000)
14439 			slot = 1000;
14440 	}
14441 	if (bbr->bbr_hdrw_pacing && (bbr->hw_pacing_set == 0)) {
14442 		/*
14443 		 * We don't change the tso size until some number of sends
14444 		 * to give the hardware commands time to get down
14445 		 * to the interface.
14446 		 */
14447 		bbr->r_ctl.bbr_hdwr_cnt_noset_snt++;
14448 		if (bbr->r_ctl.bbr_hdwr_cnt_noset_snt >= bbr_hdwr_pacing_delay_cnt) {
14449 			bbr->hw_pacing_set = 1;
14450 			tcp_bbr_tso_size_check(bbr, cts);
14451 		}
14452 	}
14453 	bbr_start_hpts_timer(bbr, tp, cts, 12, slot, tot_len);
14454 	if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
14455 		/* Make sure snd_nxt is drug up */
14456 		tp->snd_nxt = tp->snd_max;
14457 	}
14458 	return (error);
14459 
14460 }
14461 
14462 /*
14463  * See bbr_output_wtime() for return values.
14464  */
14465 static int
14466 bbr_output(struct tcpcb *tp)
14467 {
14468 	int32_t ret;
14469 	struct timeval tv;
14470 	struct tcp_bbr *bbr;
14471 
14472 	NET_EPOCH_ASSERT();
14473 
14474 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
14475 	INP_WLOCK_ASSERT(tp->t_inpcb);
14476 	(void)tcp_get_usecs(&tv);
14477 	ret = bbr_output_wtime(tp, &tv);
14478 	return (ret);
14479 }
14480 
14481 static void
14482 bbr_mtu_chg(struct tcpcb *tp)
14483 {
14484 	struct tcp_bbr *bbr;
14485 	struct bbr_sendmap *rsm, *frsm = NULL;
14486 	uint32_t maxseg;
14487 
14488 	/*
14489 	 * The MTU has changed. a) Clear the sack filter. b) Mark everything
14490 	 * over the current size as SACK_PASS so a retransmit will occur.
14491 	 */
14492 
14493 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
14494 	maxseg = tp->t_maxseg - bbr->rc_last_options;
14495 	sack_filter_clear(&bbr->r_ctl.bbr_sf, tp->snd_una);
14496 	TAILQ_FOREACH(rsm, &bbr->r_ctl.rc_map, r_next) {
14497 		/* Don't mess with ones acked (by sack?) */
14498 		if (rsm->r_flags & BBR_ACKED)
14499 			continue;
14500 		if ((rsm->r_end - rsm->r_start) > maxseg) {
14501 			/*
14502 			 * We mark sack-passed on all the previous large
14503 			 * sends we did. This will force them to retransmit.
14504 			 */
14505 			rsm->r_flags |= BBR_SACK_PASSED;
14506 			if (((rsm->r_flags & BBR_MARKED_LOST) == 0) &&
14507 			    bbr_is_lost(bbr, rsm, bbr->r_ctl.rc_rcvtime)) {
14508 				bbr->r_ctl.rc_lost_bytes += rsm->r_end - rsm->r_start;
14509 				bbr->r_ctl.rc_lost += rsm->r_end - rsm->r_start;
14510 				rsm->r_flags |= BBR_MARKED_LOST;
14511 			}
14512 			if (frsm == NULL)
14513 				frsm = rsm;
14514 		}
14515 	}
14516 	if (frsm) {
14517 		bbr->r_ctl.rc_resend = frsm;
14518 	}
14519 }
14520 
14521 /*
14522  * bbr_ctloutput() must drop the inpcb lock before performing copyin on
14523  * socket option arguments.  When it re-acquires the lock after the copy, it
14524  * has to revalidate that the connection is still valid for the socket
14525  * option.
14526  */
14527 static int
14528 bbr_set_sockopt(struct socket *so, struct sockopt *sopt,
14529 		struct inpcb *inp, struct tcpcb *tp, struct tcp_bbr *bbr)
14530 {
14531 	int32_t error = 0, optval;
14532 
14533 	switch (sopt->sopt_name) {
14534 	case TCP_RACK_PACE_MAX_SEG:
14535 	case TCP_RACK_MIN_TO:
14536 	case TCP_RACK_REORD_THRESH:
14537 	case TCP_RACK_REORD_FADE:
14538 	case TCP_RACK_TLP_THRESH:
14539 	case TCP_RACK_PKT_DELAY:
14540 	case TCP_BBR_ALGORITHM:
14541 	case TCP_BBR_TSLIMITS:
14542 	case TCP_BBR_IWINTSO:
14543 	case TCP_BBR_RECFORCE:
14544 	case TCP_BBR_STARTUP_PG:
14545 	case TCP_BBR_DRAIN_PG:
14546 	case TCP_BBR_RWND_IS_APP:
14547 	case TCP_BBR_PROBE_RTT_INT:
14548 	case TCP_BBR_PROBE_RTT_GAIN:
14549 	case TCP_BBR_PROBE_RTT_LEN:
14550 	case TCP_BBR_STARTUP_LOSS_EXIT:
14551 	case TCP_BBR_USEDEL_RATE:
14552 	case TCP_BBR_MIN_RTO:
14553 	case TCP_BBR_MAX_RTO:
14554 	case TCP_BBR_PACE_PER_SEC:
14555 	case TCP_DELACK:
14556 	case TCP_BBR_PACE_DEL_TAR:
14557 	case TCP_BBR_SEND_IWND_IN_TSO:
14558 	case TCP_BBR_EXTRA_STATE:
14559 	case TCP_BBR_UTTER_MAX_TSO:
14560 	case TCP_BBR_MIN_TOPACEOUT:
14561 	case TCP_BBR_FLOOR_MIN_TSO:
14562 	case TCP_BBR_TSTMP_RAISES:
14563 	case TCP_BBR_POLICER_DETECT:
14564 	case TCP_BBR_USE_RACK_CHEAT:
14565 	case TCP_DATA_AFTER_CLOSE:
14566 	case TCP_BBR_HDWR_PACE:
14567 	case TCP_BBR_PACE_SEG_MAX:
14568 	case TCP_BBR_PACE_SEG_MIN:
14569 	case TCP_BBR_PACE_CROSS:
14570 	case TCP_BBR_PACE_OH:
14571 #ifdef NETFLIX_PEAKRATE
14572 	case TCP_MAXPEAKRATE:
14573 #endif
14574 	case TCP_BBR_TMR_PACE_OH:
14575 	case TCP_BBR_RACK_RTT_USE:
14576 	case TCP_BBR_RETRAN_WTSO:
14577 		break;
14578 	default:
14579 		return (tcp_default_ctloutput(so, sopt, inp, tp));
14580 		break;
14581 	}
14582 	INP_WUNLOCK(inp);
14583 	error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
14584 	if (error)
14585 		return (error);
14586 	INP_WLOCK(inp);
14587 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
14588 		INP_WUNLOCK(inp);
14589 		return (ECONNRESET);
14590 	}
14591 	tp = intotcpcb(inp);
14592 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
14593 	switch (sopt->sopt_name) {
14594 	case TCP_BBR_PACE_PER_SEC:
14595 		BBR_OPTS_INC(tcp_bbr_pace_per_sec);
14596 		bbr->r_ctl.bbr_hptsi_per_second = optval;
14597 		break;
14598 	case TCP_BBR_PACE_DEL_TAR:
14599 		BBR_OPTS_INC(tcp_bbr_pace_del_tar);
14600 		bbr->r_ctl.bbr_hptsi_segments_delay_tar = optval;
14601 		break;
14602 	case TCP_BBR_PACE_SEG_MAX:
14603 		BBR_OPTS_INC(tcp_bbr_pace_seg_max);
14604 		bbr->r_ctl.bbr_hptsi_segments_max = optval;
14605 		break;
14606 	case TCP_BBR_PACE_SEG_MIN:
14607 		BBR_OPTS_INC(tcp_bbr_pace_seg_min);
14608 		bbr->r_ctl.bbr_hptsi_bytes_min = optval;
14609 		break;
14610 	case TCP_BBR_PACE_CROSS:
14611 		BBR_OPTS_INC(tcp_bbr_pace_cross);
14612 		bbr->r_ctl.bbr_cross_over = optval;
14613 		break;
14614 	case TCP_BBR_ALGORITHM:
14615 		BBR_OPTS_INC(tcp_bbr_algorithm);
14616 		if (optval && (bbr->rc_use_google == 0)) {
14617 			/* Turn on the google mode */
14618 			bbr_google_mode_on(bbr);
14619 			if ((optval > 3) && (optval < 500)) {
14620 				/*
14621 				 * Must be at least greater than .3%
14622 				 * and must be less than 50.0%.
14623 				 */
14624 				bbr->r_ctl.bbr_google_discount = optval;
14625 			}
14626 		} else if ((optval == 0) && (bbr->rc_use_google == 1)) {
14627 			/* Turn off the google mode */
14628 			bbr_google_mode_off(bbr);
14629 		}
14630 		break;
14631 	case TCP_BBR_TSLIMITS:
14632 		BBR_OPTS_INC(tcp_bbr_tslimits);
14633 		if (optval == 1)
14634 			bbr->rc_use_ts_limit = 1;
14635 		else if (optval == 0)
14636 			bbr->rc_use_ts_limit = 0;
14637 		else
14638 			error = EINVAL;
14639 		break;
14640 
14641 	case TCP_BBR_IWINTSO:
14642 		BBR_OPTS_INC(tcp_bbr_iwintso);
14643 		if ((optval >= 0) && (optval < 128)) {
14644 			uint32_t twin;
14645 
14646 			bbr->rc_init_win = optval;
14647 			twin = bbr_initial_cwnd(bbr, tp);
14648 			if ((bbr->rc_past_init_win == 0) && (twin > tp->snd_cwnd))
14649 				tp->snd_cwnd = twin;
14650 			else
14651 				error = EBUSY;
14652 		} else
14653 			error = EINVAL;
14654 		break;
14655 	case TCP_BBR_STARTUP_PG:
14656 		BBR_OPTS_INC(tcp_bbr_startup_pg);
14657 		if ((optval > 0) && (optval < BBR_MAX_GAIN_VALUE)) {
14658 			bbr->r_ctl.rc_startup_pg = optval;
14659 			if (bbr->rc_bbr_state == BBR_STATE_STARTUP) {
14660 				bbr->r_ctl.rc_bbr_hptsi_gain = optval;
14661 			}
14662 		} else
14663 			error = EINVAL;
14664 		break;
14665 	case TCP_BBR_DRAIN_PG:
14666 		BBR_OPTS_INC(tcp_bbr_drain_pg);
14667 		if ((optval > 0) && (optval < BBR_MAX_GAIN_VALUE))
14668 			bbr->r_ctl.rc_drain_pg = optval;
14669 		else
14670 			error = EINVAL;
14671 		break;
14672 	case TCP_BBR_PROBE_RTT_LEN:
14673 		BBR_OPTS_INC(tcp_bbr_probertt_len);
14674 		if (optval <= 1)
14675 			reset_time_small(&bbr->r_ctl.rc_rttprop, (optval * USECS_IN_SECOND));
14676 		else
14677 			error = EINVAL;
14678 		break;
14679 	case TCP_BBR_PROBE_RTT_GAIN:
14680 		BBR_OPTS_INC(tcp_bbr_probertt_gain);
14681 		if (optval <= BBR_UNIT)
14682 			bbr->r_ctl.bbr_rttprobe_gain_val = optval;
14683 		else
14684 			error = EINVAL;
14685 		break;
14686 	case TCP_BBR_PROBE_RTT_INT:
14687 		BBR_OPTS_INC(tcp_bbr_probe_rtt_int);
14688 		if (optval > 1000)
14689 			bbr->r_ctl.rc_probertt_int = optval;
14690 		else
14691 			error = EINVAL;
14692 		break;
14693 	case TCP_BBR_MIN_TOPACEOUT:
14694 		BBR_OPTS_INC(tcp_bbr_topaceout);
14695 		if (optval == 0) {
14696 			bbr->no_pacing_until = 0;
14697 			bbr->rc_no_pacing = 0;
14698 		} else if (optval <= 0x00ff) {
14699 			bbr->no_pacing_until = optval;
14700 			if ((bbr->r_ctl.rc_pkt_epoch < bbr->no_pacing_until) &&
14701 			    (bbr->rc_bbr_state == BBR_STATE_STARTUP)){
14702 				/* Turn on no pacing */
14703 				bbr->rc_no_pacing = 1;
14704 			}
14705 		} else
14706 			error = EINVAL;
14707 		break;
14708 	case TCP_BBR_STARTUP_LOSS_EXIT:
14709 		BBR_OPTS_INC(tcp_bbr_startup_loss_exit);
14710 		bbr->rc_loss_exit = optval;
14711 		break;
14712 	case TCP_BBR_USEDEL_RATE:
14713 		error = EINVAL;
14714 		break;
14715 	case TCP_BBR_MIN_RTO:
14716 		BBR_OPTS_INC(tcp_bbr_min_rto);
14717 		bbr->r_ctl.rc_min_rto_ms = optval;
14718 		break;
14719 	case TCP_BBR_MAX_RTO:
14720 		BBR_OPTS_INC(tcp_bbr_max_rto);
14721 		bbr->rc_max_rto_sec = optval;
14722 		break;
14723 	case TCP_RACK_MIN_TO:
14724 		/* Minimum time between rack t-o's in ms */
14725 		BBR_OPTS_INC(tcp_rack_min_to);
14726 		bbr->r_ctl.rc_min_to = optval;
14727 		break;
14728 	case TCP_RACK_REORD_THRESH:
14729 		/* RACK reorder threshold (shift amount) */
14730 		BBR_OPTS_INC(tcp_rack_reord_thresh);
14731 		if ((optval > 0) && (optval < 31))
14732 			bbr->r_ctl.rc_reorder_shift = optval;
14733 		else
14734 			error = EINVAL;
14735 		break;
14736 	case TCP_RACK_REORD_FADE:
14737 		/* Does reordering fade after ms time */
14738 		BBR_OPTS_INC(tcp_rack_reord_fade);
14739 		bbr->r_ctl.rc_reorder_fade = optval;
14740 		break;
14741 	case TCP_RACK_TLP_THRESH:
14742 		/* RACK TLP theshold i.e. srtt+(srtt/N) */
14743 		BBR_OPTS_INC(tcp_rack_tlp_thresh);
14744 		if (optval)
14745 			bbr->rc_tlp_threshold = optval;
14746 		else
14747 			error = EINVAL;
14748 		break;
14749 	case TCP_BBR_USE_RACK_CHEAT:
14750 		BBR_OPTS_INC(tcp_use_rackcheat);
14751 		if (bbr->rc_use_google) {
14752 			error = EINVAL;
14753 			break;
14754 		}
14755 		BBR_OPTS_INC(tcp_rack_cheat);
14756 		if (optval)
14757 			bbr->bbr_use_rack_cheat = 1;
14758 		else
14759 			bbr->bbr_use_rack_cheat = 0;
14760 		break;
14761 	case TCP_BBR_FLOOR_MIN_TSO:
14762 		BBR_OPTS_INC(tcp_utter_max_tso);
14763 		if ((optval >= 0) && (optval < 40))
14764 			bbr->r_ctl.bbr_hptsi_segments_floor = optval;
14765 		else
14766 			error = EINVAL;
14767 		break;
14768 	case TCP_BBR_UTTER_MAX_TSO:
14769 		BBR_OPTS_INC(tcp_utter_max_tso);
14770 		if ((optval >= 0) && (optval < 0xffff))
14771 			bbr->r_ctl.bbr_utter_max = optval;
14772 		else
14773 			error = EINVAL;
14774 		break;
14775 
14776 	case TCP_BBR_EXTRA_STATE:
14777 		BBR_OPTS_INC(tcp_extra_state);
14778 		if (optval)
14779 			bbr->rc_use_idle_restart = 1;
14780 		else
14781 			bbr->rc_use_idle_restart = 0;
14782 		break;
14783 	case TCP_BBR_SEND_IWND_IN_TSO:
14784 		BBR_OPTS_INC(tcp_iwnd_tso);
14785 		if (optval) {
14786 			bbr->bbr_init_win_cheat = 1;
14787 			if (bbr->rc_past_init_win == 0) {
14788 				uint32_t cts;
14789 				cts = tcp_get_usecs(&bbr->rc_tv);
14790 				tcp_bbr_tso_size_check(bbr, cts);
14791 			}
14792 		} else
14793 			bbr->bbr_init_win_cheat = 0;
14794 		break;
14795 	case TCP_BBR_HDWR_PACE:
14796 		BBR_OPTS_INC(tcp_hdwr_pacing);
14797 		if (optval){
14798 			bbr->bbr_hdw_pace_ena = 1;
14799 			bbr->bbr_attempt_hdwr_pace = 0;
14800 		} else {
14801 			bbr->bbr_hdw_pace_ena = 0;
14802 #ifdef RATELIMIT
14803 			if (bbr->bbr_hdrw_pacing) {
14804 				bbr->bbr_hdrw_pacing = 0;
14805 				in_pcbdetach_txrtlmt(bbr->rc_inp);
14806 			}
14807 #endif
14808 		}
14809 		break;
14810 
14811 	case TCP_DELACK:
14812 		BBR_OPTS_INC(tcp_delack);
14813 		if (optval < 100) {
14814 			if (optval == 0) /* off */
14815 				tp->t_delayed_ack = 0;
14816 			else if (optval == 1) /* on which is 2 */
14817 				tp->t_delayed_ack = 2;
14818 			else /* higher than 2 and less than 100 */
14819 				tp->t_delayed_ack = optval;
14820 			if (tp->t_flags & TF_DELACK) {
14821 				tp->t_flags &= ~TF_DELACK;
14822 				tp->t_flags |= TF_ACKNOW;
14823 				bbr_output(tp);
14824 			}
14825 		} else
14826 			error = EINVAL;
14827 		break;
14828 	case TCP_RACK_PKT_DELAY:
14829 		/* RACK added ms i.e. rack-rtt + reord + N */
14830 		BBR_OPTS_INC(tcp_rack_pkt_delay);
14831 		bbr->r_ctl.rc_pkt_delay = optval;
14832 		break;
14833 #ifdef NETFLIX_PEAKRATE
14834 	case TCP_MAXPEAKRATE:
14835 		BBR_OPTS_INC(tcp_maxpeak);
14836 		error = tcp_set_maxpeakrate(tp, optval);
14837 		if (!error)
14838 			tp->t_peakrate_thr = tp->t_maxpeakrate;
14839 		break;
14840 #endif
14841 	case TCP_BBR_RETRAN_WTSO:
14842 		BBR_OPTS_INC(tcp_retran_wtso);
14843 		if (optval)
14844 			bbr->rc_resends_use_tso = 1;
14845 		else
14846 			bbr->rc_resends_use_tso = 0;
14847 		break;
14848 	case TCP_DATA_AFTER_CLOSE:
14849 		BBR_OPTS_INC(tcp_data_ac);
14850 		if (optval)
14851 			bbr->rc_allow_data_af_clo = 1;
14852 		else
14853 			bbr->rc_allow_data_af_clo = 0;
14854 		break;
14855 	case TCP_BBR_POLICER_DETECT:
14856 		BBR_OPTS_INC(tcp_policer_det);
14857 		if (bbr->rc_use_google == 0)
14858 			error = EINVAL;
14859 		else if (optval)
14860 			bbr->r_use_policer = 1;
14861 		else
14862 			bbr->r_use_policer = 0;
14863 		break;
14864 
14865 	case TCP_BBR_TSTMP_RAISES:
14866 		BBR_OPTS_INC(tcp_ts_raises);
14867 		if (optval)
14868 			bbr->ts_can_raise = 1;
14869 		else
14870 			bbr->ts_can_raise = 0;
14871 		break;
14872 	case TCP_BBR_TMR_PACE_OH:
14873 		BBR_OPTS_INC(tcp_pacing_oh_tmr);
14874 		if (bbr->rc_use_google) {
14875 			error = EINVAL;
14876 		} else {
14877 			if (optval)
14878 				bbr->r_ctl.rc_incr_tmrs = 1;
14879 			else
14880 				bbr->r_ctl.rc_incr_tmrs = 0;
14881 		}
14882 		break;
14883 	case TCP_BBR_PACE_OH:
14884 		BBR_OPTS_INC(tcp_pacing_oh);
14885 		if (bbr->rc_use_google) {
14886 			error = EINVAL;
14887 		} else {
14888 			if (optval > (BBR_INCL_TCP_OH|
14889 				      BBR_INCL_IP_OH|
14890 				      BBR_INCL_ENET_OH)) {
14891 				error = EINVAL;
14892 				break;
14893 			}
14894 			if (optval & BBR_INCL_TCP_OH)
14895 				bbr->r_ctl.rc_inc_tcp_oh = 1;
14896 			else
14897 				bbr->r_ctl.rc_inc_tcp_oh = 0;
14898 			if (optval & BBR_INCL_IP_OH)
14899 				bbr->r_ctl.rc_inc_ip_oh = 1;
14900 			else
14901 				bbr->r_ctl.rc_inc_ip_oh = 0;
14902 			if (optval & BBR_INCL_ENET_OH)
14903 				bbr->r_ctl.rc_inc_enet_oh = 1;
14904 			else
14905 				bbr->r_ctl.rc_inc_enet_oh = 0;
14906 		}
14907 		break;
14908 	default:
14909 		return (tcp_default_ctloutput(so, sopt, inp, tp));
14910 		break;
14911 	}
14912 #ifdef NETFLIX_STATS
14913 	tcp_log_socket_option(tp, sopt->sopt_name, optval, error);
14914 #endif
14915 	INP_WUNLOCK(inp);
14916 	return (error);
14917 }
14918 
14919 /*
14920  * return 0 on success, error-num on failure
14921  */
14922 static int
14923 bbr_get_sockopt(struct socket *so, struct sockopt *sopt,
14924     struct inpcb *inp, struct tcpcb *tp, struct tcp_bbr *bbr)
14925 {
14926 	int32_t error, optval;
14927 
14928 	/*
14929 	 * Because all our options are either boolean or an int, we can just
14930 	 * pull everything into optval and then unlock and copy. If we ever
14931 	 * add a option that is not a int, then this will have quite an
14932 	 * impact to this routine.
14933 	 */
14934 	switch (sopt->sopt_name) {
14935 	case TCP_BBR_PACE_PER_SEC:
14936 		optval = bbr->r_ctl.bbr_hptsi_per_second;
14937 		break;
14938 	case TCP_BBR_PACE_DEL_TAR:
14939 		optval = bbr->r_ctl.bbr_hptsi_segments_delay_tar;
14940 		break;
14941 	case TCP_BBR_PACE_SEG_MAX:
14942 		optval = bbr->r_ctl.bbr_hptsi_segments_max;
14943 		break;
14944 	case TCP_BBR_MIN_TOPACEOUT:
14945 		optval = bbr->no_pacing_until;
14946 		break;
14947 	case TCP_BBR_PACE_SEG_MIN:
14948 		optval = bbr->r_ctl.bbr_hptsi_bytes_min;
14949 		break;
14950 	case TCP_BBR_PACE_CROSS:
14951 		optval = bbr->r_ctl.bbr_cross_over;
14952 		break;
14953 	case TCP_BBR_ALGORITHM:
14954 		optval = bbr->rc_use_google;
14955 		break;
14956 	case TCP_BBR_TSLIMITS:
14957 		optval = bbr->rc_use_ts_limit;
14958 		break;
14959 	case TCP_BBR_IWINTSO:
14960 		optval = bbr->rc_init_win;
14961 		break;
14962 	case TCP_BBR_STARTUP_PG:
14963 		optval = bbr->r_ctl.rc_startup_pg;
14964 		break;
14965 	case TCP_BBR_DRAIN_PG:
14966 		optval = bbr->r_ctl.rc_drain_pg;
14967 		break;
14968 	case TCP_BBR_PROBE_RTT_INT:
14969 		optval = bbr->r_ctl.rc_probertt_int;
14970 		break;
14971 	case TCP_BBR_PROBE_RTT_LEN:
14972 		optval = (bbr->r_ctl.rc_rttprop.cur_time_limit / USECS_IN_SECOND);
14973 		break;
14974 	case TCP_BBR_PROBE_RTT_GAIN:
14975 		optval = bbr->r_ctl.bbr_rttprobe_gain_val;
14976 		break;
14977 	case TCP_BBR_STARTUP_LOSS_EXIT:
14978 		optval = bbr->rc_loss_exit;
14979 		break;
14980 	case TCP_BBR_USEDEL_RATE:
14981 		error = EINVAL;
14982 		break;
14983 	case TCP_BBR_MIN_RTO:
14984 		optval = bbr->r_ctl.rc_min_rto_ms;
14985 		break;
14986 	case TCP_BBR_MAX_RTO:
14987 		optval = bbr->rc_max_rto_sec;
14988 		break;
14989 	case TCP_RACK_PACE_MAX_SEG:
14990 		/* Max segments in a pace */
14991 		optval = bbr->r_ctl.rc_pace_max_segs;
14992 		break;
14993 	case TCP_RACK_MIN_TO:
14994 		/* Minimum time between rack t-o's in ms */
14995 		optval = bbr->r_ctl.rc_min_to;
14996 		break;
14997 	case TCP_RACK_REORD_THRESH:
14998 		/* RACK reorder threshold (shift amount) */
14999 		optval = bbr->r_ctl.rc_reorder_shift;
15000 		break;
15001 	case TCP_RACK_REORD_FADE:
15002 		/* Does reordering fade after ms time */
15003 		optval = bbr->r_ctl.rc_reorder_fade;
15004 		break;
15005 	case TCP_BBR_USE_RACK_CHEAT:
15006 		/* Do we use the rack cheat for rxt */
15007 		optval = bbr->bbr_use_rack_cheat;
15008 		break;
15009 	case TCP_BBR_FLOOR_MIN_TSO:
15010 		optval = bbr->r_ctl.bbr_hptsi_segments_floor;
15011 		break;
15012 	case TCP_BBR_UTTER_MAX_TSO:
15013 		optval = bbr->r_ctl.bbr_utter_max;
15014 		break;
15015 	case TCP_BBR_SEND_IWND_IN_TSO:
15016 		/* Do we send TSO size segments initially */
15017 		optval = bbr->bbr_init_win_cheat;
15018 		break;
15019 	case TCP_BBR_EXTRA_STATE:
15020 		optval = bbr->rc_use_idle_restart;
15021 		break;
15022 	case TCP_RACK_TLP_THRESH:
15023 		/* RACK TLP theshold i.e. srtt+(srtt/N) */
15024 		optval = bbr->rc_tlp_threshold;
15025 		break;
15026 	case TCP_RACK_PKT_DELAY:
15027 		/* RACK added ms i.e. rack-rtt + reord + N */
15028 		optval = bbr->r_ctl.rc_pkt_delay;
15029 		break;
15030 	case TCP_BBR_RETRAN_WTSO:
15031 		optval = bbr->rc_resends_use_tso;
15032 		break;
15033 	case TCP_DATA_AFTER_CLOSE:
15034 		optval = bbr->rc_allow_data_af_clo;
15035 		break;
15036 	case TCP_DELACK:
15037 		optval = tp->t_delayed_ack;
15038 		break;
15039 	case TCP_BBR_HDWR_PACE:
15040 		optval = bbr->bbr_hdw_pace_ena;
15041 		break;
15042 	case TCP_BBR_POLICER_DETECT:
15043 		optval = bbr->r_use_policer;
15044 		break;
15045 	case TCP_BBR_TSTMP_RAISES:
15046 		optval = bbr->ts_can_raise;
15047 		break;
15048 	case TCP_BBR_TMR_PACE_OH:
15049 		optval = bbr->r_ctl.rc_incr_tmrs;
15050 		break;
15051 	case TCP_BBR_PACE_OH:
15052 		optval = 0;
15053 		if (bbr->r_ctl.rc_inc_tcp_oh)
15054 			optval |= BBR_INCL_TCP_OH;
15055 		if (bbr->r_ctl.rc_inc_ip_oh)
15056 			optval |= BBR_INCL_IP_OH;
15057 		if (bbr->r_ctl.rc_inc_enet_oh)
15058 			optval |= BBR_INCL_ENET_OH;
15059 		break;
15060 	default:
15061 		return (tcp_default_ctloutput(so, sopt, inp, tp));
15062 		break;
15063 	}
15064 	INP_WUNLOCK(inp);
15065 	error = sooptcopyout(sopt, &optval, sizeof optval);
15066 	return (error);
15067 }
15068 
15069 /*
15070  * return 0 on success, error-num on failure
15071  */
15072 static int
15073 bbr_ctloutput(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp)
15074 {
15075 	int32_t error = EINVAL;
15076 	struct tcp_bbr *bbr;
15077 
15078 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
15079 	if (bbr == NULL) {
15080 		/* Huh? */
15081 		goto out;
15082 	}
15083 	if (sopt->sopt_dir == SOPT_SET) {
15084 		return (bbr_set_sockopt(so, sopt, inp, tp, bbr));
15085 	} else if (sopt->sopt_dir == SOPT_GET) {
15086 		return (bbr_get_sockopt(so, sopt, inp, tp, bbr));
15087 	}
15088 out:
15089 	INP_WUNLOCK(inp);
15090 	return (error);
15091 }
15092 
15093 
15094 struct tcp_function_block __tcp_bbr = {
15095 	.tfb_tcp_block_name = __XSTRING(STACKNAME),
15096 	.tfb_tcp_output = bbr_output,
15097 	.tfb_do_queued_segments = ctf_do_queued_segments,
15098 	.tfb_do_segment_nounlock = bbr_do_segment_nounlock,
15099 	.tfb_tcp_do_segment = bbr_do_segment,
15100 	.tfb_tcp_ctloutput = bbr_ctloutput,
15101 	.tfb_tcp_fb_init = bbr_init,
15102 	.tfb_tcp_fb_fini = bbr_fini,
15103 	.tfb_tcp_timer_stop_all = bbr_stopall,
15104 	.tfb_tcp_timer_activate = bbr_timer_activate,
15105 	.tfb_tcp_timer_active = bbr_timer_active,
15106 	.tfb_tcp_timer_stop = bbr_timer_stop,
15107 	.tfb_tcp_rexmit_tmr = bbr_remxt_tmr,
15108 	.tfb_tcp_handoff_ok = bbr_handoff_ok,
15109 	.tfb_tcp_mtu_chg = bbr_mtu_chg
15110 };
15111 
15112 static const char *bbr_stack_names[] = {
15113 	__XSTRING(STACKNAME),
15114 #ifdef STACKALIAS
15115 	__XSTRING(STACKALIAS),
15116 #endif
15117 };
15118 
15119 static bool bbr_mod_inited = false;
15120 
15121 static int
15122 tcp_addbbr(module_t mod, int32_t type, void *data)
15123 {
15124 	int32_t err = 0;
15125 	int num_stacks;
15126 
15127 	switch (type) {
15128 	case MOD_LOAD:
15129 		printf("Attempting to load " __XSTRING(MODNAME) "\n");
15130 		bbr_zone = uma_zcreate(__XSTRING(MODNAME) "_map",
15131 		    sizeof(struct bbr_sendmap),
15132 		    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
15133 		bbr_pcb_zone = uma_zcreate(__XSTRING(MODNAME) "_pcb",
15134 		    sizeof(struct tcp_bbr),
15135 		    NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
15136 		sysctl_ctx_init(&bbr_sysctl_ctx);
15137 		bbr_sysctl_root = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
15138 		    SYSCTL_STATIC_CHILDREN(_net_inet_tcp),
15139 		    OID_AUTO,
15140 #ifdef STACKALIAS
15141 		    __XSTRING(STACKALIAS),
15142 #else
15143 		    __XSTRING(STACKNAME),
15144 #endif
15145 		    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
15146 		    "");
15147 		if (bbr_sysctl_root == NULL) {
15148 			printf("Failed to add sysctl node\n");
15149 			err = EFAULT;
15150 			goto free_uma;
15151 		}
15152 		bbr_init_sysctls();
15153 		num_stacks = nitems(bbr_stack_names);
15154 		err = register_tcp_functions_as_names(&__tcp_bbr, M_WAITOK,
15155 		    bbr_stack_names, &num_stacks);
15156 		if (err) {
15157 			printf("Failed to register %s stack name for "
15158 			    "%s module\n", bbr_stack_names[num_stacks],
15159 			    __XSTRING(MODNAME));
15160 			sysctl_ctx_free(&bbr_sysctl_ctx);
15161 	free_uma:
15162 			uma_zdestroy(bbr_zone);
15163 			uma_zdestroy(bbr_pcb_zone);
15164 			bbr_counter_destroy();
15165 			printf("Failed to register " __XSTRING(MODNAME)
15166 			    " module err:%d\n", err);
15167 			return (err);
15168 		}
15169 		tcp_lro_reg_mbufq();
15170 		bbr_mod_inited = true;
15171 		printf(__XSTRING(MODNAME) " is now available\n");
15172 		break;
15173 	case MOD_QUIESCE:
15174 		err = deregister_tcp_functions(&__tcp_bbr, true, false);
15175 		break;
15176 	case MOD_UNLOAD:
15177 		err = deregister_tcp_functions(&__tcp_bbr, false, true);
15178 		if (err == EBUSY)
15179 			break;
15180 		if (bbr_mod_inited) {
15181 			uma_zdestroy(bbr_zone);
15182 			uma_zdestroy(bbr_pcb_zone);
15183 			sysctl_ctx_free(&bbr_sysctl_ctx);
15184 			bbr_counter_destroy();
15185 			printf(__XSTRING(MODNAME)
15186 			    " is now no longer available\n");
15187 			bbr_mod_inited = false;
15188 		}
15189 		tcp_lro_dereg_mbufq();
15190 		err = 0;
15191 		break;
15192 	default:
15193 		return (EOPNOTSUPP);
15194 	}
15195 	return (err);
15196 }
15197 
15198 static moduledata_t tcp_bbr = {
15199 	.name = __XSTRING(MODNAME),
15200 	    .evhand = tcp_addbbr,
15201 	    .priv = 0
15202 };
15203 
15204 MODULE_VERSION(MODNAME, 1);
15205 DECLARE_MODULE(MODNAME, tcp_bbr, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
15206 MODULE_DEPEND(MODNAME, tcphpts, 1, 1, 1);
15207