xref: /freebsd/sys/netinet/tcp_stacks/bbr.c (revision b62ae61446ee19ab524fea4a066f585cbd7aa727)
1 /*-
2  * Copyright (c) 2016-2020 Netflix, Inc.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  *
25  */
26 /**
27  * Author: Randall Stewart <rrs@netflix.com>
28  * This work is based on the ACM Queue paper
29  * BBR - Congestion Based Congestion Control
30  * and also numerous discussions with Neal, Yuchung and Van.
31  */
32 
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include "opt_inet.h"
37 #include "opt_inet6.h"
38 #include "opt_ipsec.h"
39 #include "opt_tcpdebug.h"
40 #include "opt_ratelimit.h"
41 #include <sys/param.h>
42 #include <sys/arb.h>
43 #include <sys/module.h>
44 #include <sys/kernel.h>
45 #include <sys/libkern.h>
46 #ifdef TCP_HHOOK
47 #include <sys/hhook.h>
48 #endif
49 #include <sys/malloc.h>
50 #include <sys/mbuf.h>
51 #include <sys/proc.h>
52 #include <sys/socket.h>
53 #include <sys/socketvar.h>
54 #include <sys/sysctl.h>
55 #include <sys/systm.h>
56 #ifdef STATS
57 #include <sys/qmath.h>
58 #include <sys/tree.h>
59 #include <sys/stats.h> /* Must come after qmath.h and tree.h */
60 #endif
61 #include <sys/refcount.h>
62 #include <sys/queue.h>
63 #include <sys/eventhandler.h>
64 #include <sys/smp.h>
65 #include <sys/kthread.h>
66 #include <sys/lock.h>
67 #include <sys/mutex.h>
68 #include <sys/tim_filter.h>
69 #include <sys/time.h>
70 #include <sys/protosw.h>
71 #include <vm/uma.h>
72 #include <sys/kern_prefetch.h>
73 
74 #include <net/route.h>
75 #include <net/route/nhop.h>
76 #include <net/vnet.h>
77 
78 #define TCPSTATES		/* for logging */
79 
80 #include <netinet/in.h>
81 #include <netinet/in_kdtrace.h>
82 #include <netinet/in_pcb.h>
83 #include <netinet/ip.h>
84 #include <netinet/ip_icmp.h>	/* required for icmp_var.h */
85 #include <netinet/icmp_var.h>	/* for ICMP_BANDLIM */
86 #include <netinet/ip_var.h>
87 #include <netinet/ip6.h>
88 #include <netinet6/in6_pcb.h>
89 #include <netinet6/ip6_var.h>
90 #define	TCPOUTFLAGS
91 #include <netinet/tcp.h>
92 #include <netinet/tcp_fsm.h>
93 #include <netinet/tcp_seq.h>
94 #include <netinet/tcp_timer.h>
95 #include <netinet/tcp_var.h>
96 #include <netinet/tcpip.h>
97 #include <netinet/tcp_hpts.h>
98 #include <netinet/cc/cc.h>
99 #include <netinet/tcp_log_buf.h>
100 #include <netinet/tcp_ratelimit.h>
101 #include <netinet/tcp_lro.h>
102 #ifdef TCPDEBUG
103 #include <netinet/tcp_debug.h>
104 #endif				/* TCPDEBUG */
105 #ifdef TCP_OFFLOAD
106 #include <netinet/tcp_offload.h>
107 #endif
108 #ifdef INET6
109 #include <netinet6/tcp6_var.h>
110 #endif
111 #include <netinet/tcp_fastopen.h>
112 
113 #include <netipsec/ipsec_support.h>
114 #include <net/if.h>
115 #include <net/if_var.h>
116 #include <net/ethernet.h>
117 
118 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
119 #include <netipsec/ipsec.h>
120 #include <netipsec/ipsec6.h>
121 #endif				/* IPSEC */
122 
123 #include <netinet/udp.h>
124 #include <netinet/udp_var.h>
125 #include <machine/in_cksum.h>
126 
127 #ifdef MAC
128 #include <security/mac/mac_framework.h>
129 #endif
130 
131 #include "sack_filter.h"
132 #include "tcp_bbr.h"
133 #include "rack_bbr_common.h"
134 uma_zone_t bbr_zone;
135 uma_zone_t bbr_pcb_zone;
136 
137 struct sysctl_ctx_list bbr_sysctl_ctx;
138 struct sysctl_oid *bbr_sysctl_root;
139 
140 #define	TCPT_RANGESET_NOSLOP(tv, value, tvmin, tvmax) do { \
141 	(tv) = (value); \
142 	if ((u_long)(tv) < (u_long)(tvmin)) \
143 		(tv) = (tvmin); \
144 	if ((u_long)(tv) > (u_long)(tvmax)) \
145 		(tv) = (tvmax); \
146 } while(0)
147 
148 /*#define BBR_INVARIANT 1*/
149 
150 /*
151  * initial window
152  */
153 static uint32_t bbr_def_init_win = 10;
154 static int32_t bbr_persist_min = 250000;	/* 250ms */
155 static int32_t bbr_persist_max = 1000000;	/* 1 Second */
156 static int32_t bbr_cwnd_may_shrink = 0;
157 static int32_t bbr_cwndtarget_rtt_touse = BBR_RTT_PROP;
158 static int32_t bbr_num_pktepo_for_del_limit = BBR_NUM_RTTS_FOR_DEL_LIMIT;
159 static int32_t bbr_hardware_pacing_limit = 8000;
160 static int32_t bbr_quanta = 3;	/* How much extra quanta do we get? */
161 static int32_t bbr_no_retran = 0;
162 
163 static int32_t bbr_error_base_paceout = 10000; /* usec to pace */
164 static int32_t bbr_max_net_error_cnt = 10;
165 /* Should the following be dynamic too -- loss wise */
166 static int32_t bbr_rtt_gain_thresh = 0;
167 /* Measurement controls */
168 static int32_t bbr_use_google_algo = 1;
169 static int32_t bbr_ts_limiting = 1;
170 static int32_t bbr_ts_can_raise = 0;
171 static int32_t bbr_do_red = 600;
172 static int32_t bbr_red_scale = 20000;
173 static int32_t bbr_red_mul = 1;
174 static int32_t bbr_red_div = 2;
175 static int32_t bbr_red_growth_restrict = 1;
176 static int32_t  bbr_target_is_bbunit = 0;
177 static int32_t bbr_drop_limit = 0;
178 /*
179  * How much gain do we need to see to
180  * stay in startup?
181  */
182 static int32_t bbr_marks_rxt_sack_passed = 0;
183 static int32_t bbr_start_exit = 25;
184 static int32_t bbr_low_start_exit = 25;	/* When we are in reduced gain */
185 static int32_t bbr_startup_loss_thresh = 2000;	/* 20.00% loss */
186 static int32_t bbr_hptsi_max_mul = 1;	/* These two mul/div assure a min pacing */
187 static int32_t bbr_hptsi_max_div = 2;	/* time, 0 means turned off. We need this
188 					 * if we go back ever to where the pacer
189 					 * has priority over timers.
190 					 */
191 static int32_t bbr_policer_call_from_rack_to = 0;
192 static int32_t bbr_policer_detection_enabled = 1;
193 static int32_t bbr_min_measurements_req = 1;	/* We need at least 2
194 						 * measurments before we are
195 						 * "good" note that 2 == 1.
196 						 * This is because we use a >
197 						 * comparison. This means if
198 						 * min_measure was 0, it takes
199 						 * num-measures > min(0) and
200 						 * you get 1 measurement and
201 						 * you are good. Set to 1, you
202 						 * have to have two
203 						 * measurements (this is done
204 						 * to prevent it from being ok
205 						 * to have no measurements). */
206 static int32_t bbr_no_pacing_until = 4;
207 
208 static int32_t bbr_min_usec_delta = 20000;	/* 20,000 usecs */
209 static int32_t bbr_min_peer_delta = 20;		/* 20 units */
210 static int32_t bbr_delta_percent = 150;		/* 15.0 % */
211 
212 static int32_t bbr_target_cwnd_mult_limit = 8;
213 /*
214  * bbr_cwnd_min_val is the number of
215  * segments we hold to in the RTT probe
216  * state typically 4.
217  */
218 static int32_t bbr_cwnd_min_val = BBR_PROBERTT_NUM_MSS;
219 
220 static int32_t bbr_cwnd_min_val_hs = BBR_HIGHSPEED_NUM_MSS;
221 
222 static int32_t bbr_gain_to_target = 1;
223 static int32_t bbr_gain_gets_extra_too = 1;
224 /*
225  * bbr_high_gain is the 2/ln(2) value we need
226  * to double the sending rate in startup. This
227  * is used for both cwnd and hptsi gain's.
228  */
229 static int32_t bbr_high_gain = BBR_UNIT * 2885 / 1000 + 1;
230 static int32_t bbr_startup_lower = BBR_UNIT * 1500 / 1000 + 1;
231 static int32_t bbr_use_lower_gain_in_startup = 1;
232 
233 /* thresholds for reduction on drain in sub-states/drain */
234 static int32_t bbr_drain_rtt = BBR_SRTT;
235 static int32_t bbr_drain_floor = 88;
236 static int32_t google_allow_early_out = 1;
237 static int32_t google_consider_lost = 1;
238 static int32_t bbr_drain_drop_mul = 4;
239 static int32_t bbr_drain_drop_div = 5;
240 static int32_t bbr_rand_ot = 50;
241 static int32_t bbr_can_force_probertt = 0;
242 static int32_t bbr_can_adjust_probertt = 1;
243 static int32_t bbr_probertt_sets_rtt = 0;
244 static int32_t bbr_can_use_ts_for_rtt = 1;
245 static int32_t bbr_is_ratio = 0;
246 static int32_t bbr_sub_drain_app_limit = 1;
247 static int32_t bbr_prtt_slam_cwnd = 1;
248 static int32_t bbr_sub_drain_slam_cwnd = 1;
249 static int32_t bbr_slam_cwnd_in_main_drain = 1;
250 static int32_t bbr_filter_len_sec = 6;	/* How long does the rttProp filter
251 					 * hold */
252 static uint32_t bbr_rtt_probe_limit = (USECS_IN_SECOND * 4);
253 /*
254  * bbr_drain_gain is the reverse of the high_gain
255  * designed to drain back out the standing queue
256  * that is formed in startup by causing a larger
257  * hptsi gain and thus drainging the packets
258  * in flight.
259  */
260 static int32_t bbr_drain_gain = BBR_UNIT * 1000 / 2885;
261 static int32_t bbr_rttprobe_gain = 192;
262 
263 /*
264  * The cwnd_gain is the default cwnd gain applied when
265  * calculating a target cwnd. Note that the cwnd is
266  * a secondary factor in the way BBR works (see the
267  * paper and think about it, it will take some time).
268  * Basically the hptsi_gain spreads the packets out
269  * so you never get more than BDP to the peer even
270  * if the cwnd is high. In our implemenation that
271  * means in non-recovery/retransmission scenarios
272  * cwnd will never be reached by the flight-size.
273  */
274 static int32_t bbr_cwnd_gain = BBR_UNIT * 2;
275 static int32_t bbr_tlp_type_to_use = BBR_SRTT;
276 static int32_t bbr_delack_time = 100000;	/* 100ms in useconds */
277 static int32_t bbr_sack_not_required = 0;	/* set to one to allow non-sack to use bbr */
278 static int32_t bbr_initial_bw_bps = 62500;	/* 500kbps in bytes ps */
279 static int32_t bbr_ignore_data_after_close = 1;
280 static int16_t bbr_hptsi_gain[] = {
281 	(BBR_UNIT *5 / 4),
282 	(BBR_UNIT * 3 / 4),
283 	BBR_UNIT,
284 	BBR_UNIT,
285 	BBR_UNIT,
286 	BBR_UNIT,
287 	BBR_UNIT,
288 	BBR_UNIT
289 };
290 int32_t bbr_use_rack_resend_cheat = 1;
291 int32_t bbr_sends_full_iwnd = 1;
292 
293 #define BBR_HPTSI_GAIN_MAX 8
294 /*
295  * The BBR module incorporates a number of
296  * TCP ideas that have been put out into the IETF
297  * over the last few years:
298  * - Yuchung Cheng's RACK TCP (for which its named) that
299  *    will stop us using the number of dup acks and instead
300  *    use time as the gage of when we retransmit.
301  * - Reorder Detection of RFC4737 and the Tail-Loss probe draft
302  *    of Dukkipati et.al.
303  * - Van Jacobson's et.al BBR.
304  *
305  * RACK depends on SACK, so if an endpoint arrives that
306  * cannot do SACK the state machine below will shuttle the
307  * connection back to using the "default" TCP stack that is
308  * in FreeBSD.
309  *
310  * To implement BBR and RACK the original TCP stack was first decomposed
311  * into a functional state machine with individual states
312  * for each of the possible TCP connection states. The do_segement
313  * functions role in life is to mandate the connection supports SACK
314  * initially and then assure that the RACK state matches the conenction
315  * state before calling the states do_segment function. Data processing
316  * of inbound segments also now happens in the hpts_do_segment in general
317  * with only one exception. This is so we can keep the connection on
318  * a single CPU.
319  *
320  * Each state is simplified due to the fact that the original do_segment
321  * has been decomposed and we *know* what state we are in (no
322  * switches on the state) and all tests for SACK are gone. This
323  * greatly simplifies what each state does.
324  *
325  * TCP output is also over-written with a new version since it
326  * must maintain the new rack scoreboard and has had hptsi
327  * integrated as a requirment. Still todo is to eliminate the
328  * use of the callout_() system and use the hpts for all
329  * timers as well.
330  */
331 static uint32_t bbr_rtt_probe_time = 200000;	/* 200ms in micro seconds */
332 static uint32_t bbr_rtt_probe_cwndtarg = 4;	/* How many mss's outstanding */
333 static const int32_t bbr_min_req_free = 2;	/* The min we must have on the
334 						 * free list */
335 static int32_t bbr_tlp_thresh = 1;
336 static int32_t bbr_reorder_thresh = 2;
337 static int32_t bbr_reorder_fade = 60000000;	/* 0 - never fade, def
338 						 * 60,000,000 - 60 seconds */
339 static int32_t bbr_pkt_delay = 1000;
340 static int32_t bbr_min_to = 1000;	/* Number of usec's minimum timeout */
341 static int32_t bbr_incr_timers = 1;
342 
343 static int32_t bbr_tlp_min = 10000;	/* 10ms in usecs */
344 static int32_t bbr_delayed_ack_time = 200000;	/* 200ms in usecs */
345 static int32_t bbr_exit_startup_at_loss = 1;
346 
347 /*
348  * bbr_lt_bw_ratio is 1/8th
349  * bbr_lt_bw_diff is  < 4 Kbit/sec
350  */
351 static uint64_t bbr_lt_bw_diff = 4000 / 8;	/* In bytes per second */
352 static uint64_t bbr_lt_bw_ratio = 8;	/* For 1/8th */
353 static uint32_t bbr_lt_bw_max_rtts = 48;	/* How many rtt's do we use
354 						 * the lt_bw for */
355 static uint32_t bbr_lt_intvl_min_rtts = 4;	/* Min num of RTT's to measure
356 						 * lt_bw */
357 static int32_t bbr_lt_intvl_fp = 0;		/* False positive epoch diff */
358 static int32_t bbr_lt_loss_thresh = 196;	/* Lost vs delivered % */
359 static int32_t bbr_lt_fd_thresh = 100;		/* false detection % */
360 
361 static int32_t bbr_verbose_logging = 0;
362 /*
363  * Currently regular tcp has a rto_min of 30ms
364  * the backoff goes 12 times so that ends up
365  * being a total of 122.850 seconds before a
366  * connection is killed.
367  */
368 static int32_t bbr_rto_min_ms = 30;	/* 30ms same as main freebsd */
369 static int32_t bbr_rto_max_sec = 4;	/* 4 seconds */
370 
371 /****************************************************/
372 /* DEFAULT TSO SIZING  (cpu performance impacting)  */
373 /****************************************************/
374 /* What amount is our formula using to get TSO size */
375 static int32_t bbr_hptsi_per_second = 1000;
376 
377 /*
378  * For hptsi under bbr_cross_over connections what is delay
379  * target 7ms (in usec) combined with a seg_max of 2
380  * gets us close to identical google behavior in
381  * TSO size selection (possibly more 1MSS sends).
382  */
383 static int32_t bbr_hptsi_segments_delay_tar = 7000;
384 
385 /* Does pacing delay include overhead's in its time calculations? */
386 static int32_t bbr_include_enet_oh = 0;
387 static int32_t bbr_include_ip_oh = 1;
388 static int32_t bbr_include_tcp_oh = 1;
389 static int32_t bbr_google_discount = 10;
390 
391 /* Do we use (nf mode) pkt-epoch to drive us or rttProp? */
392 static int32_t bbr_state_is_pkt_epoch = 0;
393 static int32_t bbr_state_drain_2_tar = 1;
394 /* What is the max the 0 - bbr_cross_over MBPS TSO target
395  * can reach using our delay target. Note that this
396  * value becomes the floor for the cross over
397  * algorithm.
398  */
399 static int32_t bbr_hptsi_segments_max = 2;
400 static int32_t bbr_hptsi_segments_floor = 1;
401 static int32_t bbr_hptsi_utter_max = 0;
402 
403 /* What is the min the 0 - bbr_cross-over MBPS  TSO target can be */
404 static int32_t bbr_hptsi_bytes_min = 1460;
405 static int32_t bbr_all_get_min = 0;
406 
407 /* Cross over point from algo-a to algo-b */
408 static uint32_t bbr_cross_over = TWENTY_THREE_MBPS;
409 
410 /* Do we deal with our restart state? */
411 static int32_t bbr_uses_idle_restart = 0;
412 static int32_t bbr_idle_restart_threshold = 100000;	/* 100ms in useconds */
413 
414 /* Do we allow hardware pacing? */
415 static int32_t bbr_allow_hdwr_pacing = 0;
416 static int32_t bbr_hdwr_pace_adjust = 2;	/* multipler when we calc the tso size */
417 static int32_t bbr_hdwr_pace_floor = 1;
418 static int32_t bbr_hdwr_pacing_delay_cnt = 10;
419 
420 /****************************************************/
421 static int32_t bbr_resends_use_tso = 0;
422 static int32_t bbr_tlp_max_resend = 2;
423 static int32_t bbr_sack_block_limit = 128;
424 
425 #define  BBR_MAX_STAT 19
426 counter_u64_t bbr_state_time[BBR_MAX_STAT];
427 counter_u64_t bbr_state_lost[BBR_MAX_STAT];
428 counter_u64_t bbr_state_resend[BBR_MAX_STAT];
429 counter_u64_t bbr_stat_arry[BBR_STAT_SIZE];
430 counter_u64_t bbr_opts_arry[BBR_OPTS_SIZE];
431 counter_u64_t bbr_out_size[TCP_MSS_ACCT_SIZE];
432 counter_u64_t bbr_flows_whdwr_pacing;
433 counter_u64_t bbr_flows_nohdwr_pacing;
434 
435 counter_u64_t bbr_nohdwr_pacing_enobuf;
436 counter_u64_t bbr_hdwr_pacing_enobuf;
437 
438 static inline uint64_t bbr_get_bw(struct tcp_bbr *bbr);
439 
440 /*
441  * Static defintions we need for forward declarations.
442  */
443 static uint32_t
444 bbr_get_pacing_length(struct tcp_bbr *bbr, uint16_t gain,
445     uint32_t useconds_time, uint64_t bw);
446 static uint32_t
447 bbr_get_a_state_target(struct tcp_bbr *bbr, uint32_t gain);
448 static void
449      bbr_set_state(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t win);
450 static void
451 bbr_set_probebw_gains(struct tcp_bbr *bbr,  uint32_t cts, uint32_t losses);
452 static void
453 bbr_substate_change(struct tcp_bbr *bbr, uint32_t cts, int line,
454 		    int dolog);
455 static uint32_t
456 bbr_get_target_cwnd(struct tcp_bbr *bbr, uint64_t bw, uint32_t gain);
457 static void
458 bbr_state_change(struct tcp_bbr *bbr, uint32_t cts, int32_t epoch,
459 		 int32_t pkt_epoch, uint32_t losses);
460 static uint32_t
461 bbr_calc_thresh_rack(struct tcp_bbr *bbr, uint32_t srtt, uint32_t cts, struct bbr_sendmap *rsm);
462 static uint32_t bbr_initial_cwnd(struct tcp_bbr *bbr, struct tcpcb *tp);
463 static uint32_t
464 bbr_calc_thresh_tlp(struct tcpcb *tp, struct tcp_bbr *bbr,
465     struct bbr_sendmap *rsm, uint32_t srtt,
466     uint32_t cts);
467 static void
468 bbr_exit_persist(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts,
469     int32_t line);
470 static void
471      bbr_set_state_target(struct tcp_bbr *bbr, int line);
472 static void
473      bbr_enter_probe_rtt(struct tcp_bbr *bbr, uint32_t cts, int32_t line);
474 
475 static void
476      bbr_log_progress_event(struct tcp_bbr *bbr, struct tcpcb *tp, uint32_t tick, int event, int line);
477 
478 static void
479      tcp_bbr_tso_size_check(struct tcp_bbr *bbr, uint32_t cts);
480 
481 static void
482      bbr_setup_red_bw(struct tcp_bbr *bbr, uint32_t cts);
483 
484 static void
485      bbr_log_rtt_shrinks(struct tcp_bbr *bbr, uint32_t cts, uint32_t applied, uint32_t rtt,
486 			 uint32_t line, uint8_t is_start, uint16_t set);
487 
488 static struct bbr_sendmap *
489             bbr_find_lowest_rsm(struct tcp_bbr *bbr);
490 static __inline uint32_t
491 bbr_get_rtt(struct tcp_bbr *bbr, int32_t rtt_type);
492 static void
493      bbr_log_to_start(struct tcp_bbr *bbr, uint32_t cts, uint32_t to, int32_t slot, uint8_t which);
494 
495 static void
496 bbr_log_timer_var(struct tcp_bbr *bbr, int mode, uint32_t cts, uint32_t time_since_sent, uint32_t srtt,
497     uint32_t thresh, uint32_t to);
498 static void
499      bbr_log_hpts_diag(struct tcp_bbr *bbr, uint32_t cts, struct hpts_diag *diag);
500 
501 static void
502 bbr_log_type_bbrsnd(struct tcp_bbr *bbr, uint32_t len, uint32_t slot,
503     uint32_t del_by, uint32_t cts, uint32_t sloton, uint32_t prev_delay);
504 
505 static void
506 bbr_enter_persist(struct tcpcb *tp, struct tcp_bbr *bbr,
507     uint32_t cts, int32_t line);
508 static void
509      bbr_stop_all_timers(struct tcpcb *tp);
510 static void
511      bbr_exit_probe_rtt(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts);
512 static void
513      bbr_check_probe_rtt_limits(struct tcp_bbr *bbr, uint32_t cts);
514 static void
515      bbr_timer_cancel(struct tcp_bbr *bbr, int32_t line, uint32_t cts);
516 
517 static void
518 bbr_log_pacing_delay_calc(struct tcp_bbr *bbr, uint16_t gain, uint32_t len,
519     uint32_t cts, uint32_t usecs, uint64_t bw, uint32_t override, int mod);
520 
521 static inline uint8_t
522 bbr_state_val(struct tcp_bbr *bbr)
523 {
524 	return(bbr->rc_bbr_substate);
525 }
526 
527 static inline uint32_t
528 get_min_cwnd(struct tcp_bbr *bbr)
529 {
530 	int mss;
531 
532 	mss = min((bbr->rc_tp->t_maxseg - bbr->rc_last_options), bbr->r_ctl.rc_pace_max_segs);
533 	if (bbr_get_rtt(bbr, BBR_RTT_PROP) < BBR_HIGH_SPEED)
534 		return (bbr_cwnd_min_val_hs * mss);
535 	else
536 		return (bbr_cwnd_min_val * mss);
537 }
538 
539 static uint32_t
540 bbr_get_persists_timer_val(struct tcpcb *tp, struct tcp_bbr *bbr)
541 {
542 	uint64_t srtt, var;
543 	uint64_t ret_val;
544 
545 	bbr->r_ctl.rc_hpts_flags |= PACE_TMR_PERSIT;
546 	if (tp->t_srtt == 0) {
547 		srtt = (uint64_t)BBR_INITIAL_RTO;
548 		var = 0;
549 	} else {
550 		srtt = ((uint64_t)TICKS_2_USEC(tp->t_srtt) >> TCP_RTT_SHIFT);
551 		var = ((uint64_t)TICKS_2_USEC(tp->t_rttvar) >> TCP_RTT_SHIFT);
552 	}
553 	TCPT_RANGESET_NOSLOP(ret_val, ((srtt + var) * tcp_backoff[tp->t_rxtshift]),
554 	    bbr_persist_min, bbr_persist_max);
555 	return ((uint32_t)ret_val);
556 }
557 
558 static uint32_t
559 bbr_timer_start(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
560 {
561 	/*
562 	 * Start the FR timer, we do this based on getting the first one in
563 	 * the rc_tmap. Note that if its NULL we must stop the timer. in all
564 	 * events we need to stop the running timer (if its running) before
565 	 * starting the new one.
566 	 */
567 	uint32_t thresh, exp, to, srtt, time_since_sent, tstmp_touse;
568 	int32_t idx;
569 	int32_t is_tlp_timer = 0;
570 	struct bbr_sendmap *rsm;
571 
572 	if (bbr->rc_all_timers_stopped) {
573 		/* All timers have been stopped none are to run */
574 		return (0);
575 	}
576 	if (bbr->rc_in_persist) {
577 		/* We can't start any timer in persists */
578 		return (bbr_get_persists_timer_val(tp, bbr));
579 	}
580 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_tmap);
581 	if ((rsm == NULL) ||
582 	    ((tp->t_flags & TF_SACK_PERMIT) == 0) ||
583 	    (tp->t_state < TCPS_ESTABLISHED)) {
584 		/* Nothing on the send map */
585 activate_rxt:
586 		if (SEQ_LT(tp->snd_una, tp->snd_max) || sbavail(&(tp->t_inpcb->inp_socket->so_snd))) {
587 			uint64_t tov;
588 
589 			time_since_sent = 0;
590 			rsm = TAILQ_FIRST(&bbr->r_ctl.rc_tmap);
591 			if (rsm) {
592 				idx = rsm->r_rtr_cnt - 1;
593 				if (TSTMP_GEQ(rsm->r_tim_lastsent[idx], bbr->r_ctl.rc_tlp_rxt_last_time))
594 					tstmp_touse = rsm->r_tim_lastsent[idx];
595 				else
596 					tstmp_touse = bbr->r_ctl.rc_tlp_rxt_last_time;
597 				if (TSTMP_GT(tstmp_touse, cts))
598 				    time_since_sent = cts - tstmp_touse;
599 			}
600 			bbr->r_ctl.rc_hpts_flags |= PACE_TMR_RXT;
601 			if (tp->t_srtt == 0)
602 				tov = BBR_INITIAL_RTO;
603 			else
604 				tov = ((uint64_t)(TICKS_2_USEC(tp->t_srtt) +
605 				    ((uint64_t)TICKS_2_USEC(tp->t_rttvar) * (uint64_t)4)) >> TCP_RTT_SHIFT);
606 			if (tp->t_rxtshift)
607 				tov *= tcp_backoff[tp->t_rxtshift];
608 			if (tov > time_since_sent)
609 				tov -= time_since_sent;
610 			else
611 				tov = bbr->r_ctl.rc_min_to;
612 			TCPT_RANGESET_NOSLOP(to, tov,
613 			    (bbr->r_ctl.rc_min_rto_ms * MS_IN_USEC),
614 			    (bbr->rc_max_rto_sec * USECS_IN_SECOND));
615 			bbr_log_timer_var(bbr, 2, cts, 0, srtt, 0, to);
616 			return (to);
617 		}
618 		return (0);
619 	}
620 	if (rsm->r_flags & BBR_ACKED) {
621 		rsm = bbr_find_lowest_rsm(bbr);
622 		if (rsm == NULL) {
623 			/* No lowest? */
624 			goto activate_rxt;
625 		}
626 	}
627 	/* Convert from ms to usecs */
628 	if (rsm->r_flags & BBR_SACK_PASSED) {
629 		if ((tp->t_flags & TF_SENTFIN) &&
630 		    ((tp->snd_max - tp->snd_una) == 1) &&
631 		    (rsm->r_flags & BBR_HAS_FIN)) {
632 			/*
633 			 * We don't start a bbr rack timer if all we have is
634 			 * a FIN outstanding.
635 			 */
636 			goto activate_rxt;
637 		}
638 		srtt = bbr_get_rtt(bbr, BBR_RTT_RACK);
639 		thresh = bbr_calc_thresh_rack(bbr, srtt, cts, rsm);
640 		idx = rsm->r_rtr_cnt - 1;
641 		exp = rsm->r_tim_lastsent[idx] + thresh;
642 		if (SEQ_GEQ(exp, cts)) {
643 			to = exp - cts;
644 			if (to < bbr->r_ctl.rc_min_to) {
645 				to = bbr->r_ctl.rc_min_to;
646 			}
647 		} else {
648 			to = bbr->r_ctl.rc_min_to;
649 		}
650 	} else {
651 		/* Ok we need to do a TLP not RACK */
652 		if (bbr->rc_tlp_in_progress != 0) {
653 			/*
654 			 * The previous send was a TLP.
655 			 */
656 			goto activate_rxt;
657 		}
658 		rsm = TAILQ_LAST_FAST(&bbr->r_ctl.rc_tmap, bbr_sendmap, r_tnext);
659 		if (rsm == NULL) {
660 			/* We found no rsm to TLP with. */
661 			goto activate_rxt;
662 		}
663 		if (rsm->r_flags & BBR_HAS_FIN) {
664 			/* If its a FIN we don't do TLP */
665 			rsm = NULL;
666 			goto activate_rxt;
667 		}
668 		time_since_sent = 0;
669 		idx = rsm->r_rtr_cnt - 1;
670 		if (TSTMP_GEQ(rsm->r_tim_lastsent[idx], bbr->r_ctl.rc_tlp_rxt_last_time))
671 			tstmp_touse = rsm->r_tim_lastsent[idx];
672 		else
673 			tstmp_touse = bbr->r_ctl.rc_tlp_rxt_last_time;
674 		if (TSTMP_GT(tstmp_touse, cts))
675 		    time_since_sent = cts - tstmp_touse;
676 		is_tlp_timer = 1;
677 		srtt = bbr_get_rtt(bbr, bbr_tlp_type_to_use);
678 		thresh = bbr_calc_thresh_tlp(tp, bbr, rsm, srtt, cts);
679 		if (thresh > time_since_sent)
680 			to = thresh - time_since_sent;
681 		else
682 			to = bbr->r_ctl.rc_min_to;
683 		if (to > (((uint32_t)bbr->rc_max_rto_sec) * USECS_IN_SECOND)) {
684 			/*
685 			 * If the TLP time works out to larger than the max
686 			 * RTO lets not do TLP.. just RTO.
687 			 */
688 			goto activate_rxt;
689 		}
690 		if ((bbr->rc_tlp_rtx_out == 1) &&
691 		    (rsm->r_start == bbr->r_ctl.rc_last_tlp_seq)) {
692 			/*
693 			 * Second retransmit of the same TLP
694 			 * lets not.
695 			 */
696 			bbr->rc_tlp_rtx_out = 0;
697 			goto activate_rxt;
698 		}
699 		if (rsm->r_start != bbr->r_ctl.rc_last_tlp_seq) {
700 			/*
701 			 * The tail is no longer the last one I did a probe
702 			 * on
703 			 */
704 			bbr->r_ctl.rc_tlp_seg_send_cnt = 0;
705 			bbr->r_ctl.rc_last_tlp_seq = rsm->r_start;
706 		}
707 	}
708 	if (is_tlp_timer == 0) {
709 		BBR_STAT_INC(bbr_to_arm_rack);
710 		bbr->r_ctl.rc_hpts_flags |= PACE_TMR_RACK;
711 	} else {
712 		bbr_log_timer_var(bbr, 1, cts, time_since_sent, srtt, thresh, to);
713 		if (bbr->r_ctl.rc_tlp_seg_send_cnt > bbr_tlp_max_resend) {
714 			/*
715 			 * We have exceeded how many times we can retran the
716 			 * current TLP timer, switch to the RTO timer.
717 			 */
718 			goto activate_rxt;
719 		} else {
720 			BBR_STAT_INC(bbr_to_arm_tlp);
721 			bbr->r_ctl.rc_hpts_flags |= PACE_TMR_TLP;
722 		}
723 	}
724 	return (to);
725 }
726 
727 static inline int32_t
728 bbr_minseg(struct tcp_bbr *bbr)
729 {
730 	return (bbr->r_ctl.rc_pace_min_segs - bbr->rc_last_options);
731 }
732 
733 static void
734 bbr_start_hpts_timer(struct tcp_bbr *bbr, struct tcpcb *tp, uint32_t cts, int32_t frm, int32_t slot, uint32_t tot_len)
735 {
736 	struct inpcb *inp;
737 	struct hpts_diag diag;
738 	uint32_t delayed_ack = 0;
739 	uint32_t left = 0;
740 	uint32_t hpts_timeout;
741 	uint8_t stopped;
742 	int32_t delay_calc = 0;
743 	uint32_t prev_delay = 0;
744 
745 	inp = tp->t_inpcb;
746 	if (inp->inp_in_hpts) {
747 		/* A previous call is already set up */
748 		return;
749 	}
750 	if ((tp->t_state == TCPS_CLOSED) ||
751 	    (tp->t_state == TCPS_LISTEN)) {
752 		return;
753 	}
754 	stopped = bbr->rc_tmr_stopped;
755 	if (stopped && TSTMP_GT(bbr->r_ctl.rc_timer_exp, cts)) {
756 		left = bbr->r_ctl.rc_timer_exp - cts;
757 	}
758 	bbr->r_ctl.rc_hpts_flags = 0;
759 	bbr->r_ctl.rc_timer_exp = 0;
760 	prev_delay = bbr->r_ctl.rc_last_delay_val;
761 	if (bbr->r_ctl.rc_last_delay_val &&
762 	    (slot == 0)) {
763 		/*
764 		 * If a previous pacer delay was in place we
765 		 * are not coming from the output side (where
766 		 * we calculate a delay, more likely a timer).
767 		 */
768 		slot = bbr->r_ctl.rc_last_delay_val;
769 		if (TSTMP_GT(cts, bbr->rc_pacer_started)) {
770 			/* Compensate for time passed  */
771 			delay_calc = cts - bbr->rc_pacer_started;
772 			if (delay_calc <= slot)
773 				slot -= delay_calc;
774 		}
775 	}
776 	/* Do we have early to make up for by pushing out the pacing time? */
777 	if (bbr->r_agg_early_set) {
778 		bbr_log_pacing_delay_calc(bbr, 0, bbr->r_ctl.rc_agg_early, cts, slot, 0, bbr->r_agg_early_set, 2);
779 		slot += bbr->r_ctl.rc_agg_early;
780 		bbr->r_ctl.rc_agg_early = 0;
781 		bbr->r_agg_early_set = 0;
782 	}
783 	/* Are we running a total debt that needs to be compensated for? */
784 	if (bbr->r_ctl.rc_hptsi_agg_delay) {
785 		if (slot > bbr->r_ctl.rc_hptsi_agg_delay) {
786 			/* We nuke the delay */
787 			slot -= bbr->r_ctl.rc_hptsi_agg_delay;
788 			bbr->r_ctl.rc_hptsi_agg_delay = 0;
789 		} else {
790 			/* We nuke some of the delay, put in a minimal 100usecs  */
791 			bbr->r_ctl.rc_hptsi_agg_delay -= slot;
792 			bbr->r_ctl.rc_last_delay_val = slot = 100;
793 		}
794 	}
795 	bbr->r_ctl.rc_last_delay_val = slot;
796 	hpts_timeout = bbr_timer_start(tp, bbr, cts);
797 	if (tp->t_flags & TF_DELACK) {
798 		if (bbr->rc_in_persist == 0) {
799 			delayed_ack = bbr_delack_time;
800 		} else {
801 			/*
802 			 * We are in persists and have
803 			 * gotten a new data element.
804 			 */
805 			if (hpts_timeout > bbr_delack_time) {
806 				/*
807 				 * Lets make the persists timer (which acks)
808 				 * be the smaller of hpts_timeout and bbr_delack_time.
809 				 */
810 				hpts_timeout = bbr_delack_time;
811 			}
812 		}
813 	}
814 	if (delayed_ack &&
815 	    ((hpts_timeout == 0) ||
816 	     (delayed_ack < hpts_timeout))) {
817 		/* We need a Delayed ack timer */
818 		bbr->r_ctl.rc_hpts_flags = PACE_TMR_DELACK;
819 		hpts_timeout = delayed_ack;
820 	}
821 	if (slot) {
822 		/* Mark that we have a pacing timer up */
823 		BBR_STAT_INC(bbr_paced_segments);
824 		bbr->r_ctl.rc_hpts_flags |= PACE_PKT_OUTPUT;
825 	}
826 	/*
827 	 * If no timers are going to run and we will fall off thfe hptsi
828 	 * wheel, we resort to a keep-alive timer if its configured.
829 	 */
830 	if ((hpts_timeout == 0) &&
831 	    (slot == 0)) {
832 		if ((V_tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
833 		    (tp->t_state <= TCPS_CLOSING)) {
834 			/*
835 			 * Ok we have no timer (persists, rack, tlp, rxt  or
836 			 * del-ack), we don't have segments being paced. So
837 			 * all that is left is the keepalive timer.
838 			 */
839 			if (TCPS_HAVEESTABLISHED(tp->t_state)) {
840 				hpts_timeout = TICKS_2_USEC(TP_KEEPIDLE(tp));
841 			} else {
842 				hpts_timeout = TICKS_2_USEC(TP_KEEPINIT(tp));
843 			}
844 			bbr->r_ctl.rc_hpts_flags |= PACE_TMR_KEEP;
845 		}
846 	}
847 	if (left && (stopped & (PACE_TMR_KEEP | PACE_TMR_DELACK)) ==
848 	    (bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK)) {
849 		/*
850 		 * RACK, TLP, persists and RXT timers all are restartable
851 		 * based on actions input .. i.e we received a packet (ack
852 		 * or sack) and that changes things (rw, or snd_una etc).
853 		 * Thus we can restart them with a new value. For
854 		 * keep-alive, delayed_ack we keep track of what was left
855 		 * and restart the timer with a smaller value.
856 		 */
857 		if (left < hpts_timeout)
858 			hpts_timeout = left;
859 	}
860 	if (bbr->r_ctl.rc_incr_tmrs && slot &&
861 	    (bbr->r_ctl.rc_hpts_flags & (PACE_TMR_TLP|PACE_TMR_RXT))) {
862 		/*
863 		 * If configured to do so, and the timer is either
864 		 * the TLP or RXT timer, we need to increase the timeout
865 		 * by the pacing time. Consider the bottleneck at my
866 		 * machine as an example, we are sending something
867 		 * to start a TLP on. The last packet won't be emitted
868 		 * fully until the pacing time (the bottleneck will hold
869 		 * the data in place). Once the packet is emitted that
870 		 * is when we want to start waiting for the TLP. This
871 		 * is most evident with hardware pacing (where the nic
872 		 * is holding the packet(s) before emitting). But it
873 		 * can also show up in the network so we do it for all
874 		 * cases. Technically we would take off one packet from
875 		 * this extra delay but this is easier and being more
876 		 * conservative is probably better.
877 		 */
878 		hpts_timeout += slot;
879 	}
880 	if (hpts_timeout) {
881 		/*
882 		 * Hack alert for now we can't time-out over 2147 seconds (a
883 		 * bit more than 35min)
884 		 */
885 		if (hpts_timeout > 0x7ffffffe)
886 			hpts_timeout = 0x7ffffffe;
887 		bbr->r_ctl.rc_timer_exp = cts + hpts_timeout;
888 	} else
889 		bbr->r_ctl.rc_timer_exp = 0;
890 	if ((slot) &&
891 	    (bbr->rc_use_google ||
892 	     bbr->output_error_seen ||
893 	     (slot <= hpts_timeout))  ) {
894 		/*
895 		 * Tell LRO that it can queue packets while
896 		 * we pace.
897 		 */
898 		bbr->rc_inp->inp_flags2 |= INP_MBUF_QUEUE_READY;
899 		if ((bbr->r_ctl.rc_hpts_flags & PACE_TMR_RACK) &&
900 		    (bbr->rc_cwnd_limited == 0)) {
901 			/*
902 			 * If we are not cwnd limited and we
903 			 * are running a rack timer we put on
904 			 * the do not disturbe even for sack.
905 			 */
906 			inp->inp_flags2 |= INP_DONT_SACK_QUEUE;
907 		} else
908 			inp->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
909 		bbr->rc_pacer_started = cts;
910 
911 		(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_USEC_TO_SLOTS(slot),
912 					   __LINE__, &diag);
913 		bbr->rc_timer_first = 0;
914 		bbr->bbr_timer_src = frm;
915 		bbr_log_to_start(bbr, cts, hpts_timeout, slot, 1);
916 		bbr_log_hpts_diag(bbr, cts, &diag);
917 	} else if (hpts_timeout) {
918 		(void)tcp_hpts_insert_diag(tp->t_inpcb, HPTS_USEC_TO_SLOTS(hpts_timeout),
919 					   __LINE__, &diag);
920 		/*
921 		 * We add the flag here as well if the slot is set,
922 		 * since hpts will call in to clear the queue first before
923 		 * calling the output routine (which does our timers).
924 		 * We don't want to set the flag if its just a timer
925 		 * else the arrival of data might (that causes us
926 		 * to send more) might get delayed. Imagine being
927 		 * on a keep-alive timer and a request comes in for
928 		 * more data.
929 		 */
930 		if (slot)
931 			bbr->rc_pacer_started = cts;
932 		if ((bbr->r_ctl.rc_hpts_flags & PACE_TMR_RACK) &&
933 		    (bbr->rc_cwnd_limited == 0)) {
934 			/*
935 			 * For a rack timer, don't wake us even
936 			 * if a sack arrives as long as we are
937 			 * not cwnd limited.
938 			 */
939 			bbr->rc_inp->inp_flags2 |= INP_MBUF_QUEUE_READY;
940 			inp->inp_flags2 |= INP_DONT_SACK_QUEUE;
941 		} else {
942 			/* All other timers wake us up */
943 			bbr->rc_inp->inp_flags2 &= ~INP_MBUF_QUEUE_READY;
944 			inp->inp_flags2 &= ~INP_DONT_SACK_QUEUE;
945 		}
946 		bbr->bbr_timer_src = frm;
947 		bbr_log_to_start(bbr, cts, hpts_timeout, slot, 0);
948 		bbr_log_hpts_diag(bbr, cts, &diag);
949 		bbr->rc_timer_first = 1;
950 	}
951 	bbr->rc_tmr_stopped = 0;
952 	bbr_log_type_bbrsnd(bbr, tot_len, slot, delay_calc, cts, frm, prev_delay);
953 }
954 
955 static void
956 bbr_timer_audit(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts, struct sockbuf *sb)
957 {
958 	/*
959 	 * We received an ack, and then did not call send or were bounced
960 	 * out due to the hpts was running. Now a timer is up as well, is it
961 	 * the right timer?
962 	 */
963 	struct inpcb *inp;
964 	struct bbr_sendmap *rsm;
965 	uint32_t hpts_timeout;
966 	int tmr_up;
967 
968 	tmr_up = bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK;
969 	if (bbr->rc_in_persist && (tmr_up == PACE_TMR_PERSIT))
970 		return;
971 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_tmap);
972 	if (((rsm == NULL) || (tp->t_state < TCPS_ESTABLISHED)) &&
973 	    (tmr_up == PACE_TMR_RXT)) {
974 		/* Should be an RXT */
975 		return;
976 	}
977 	inp = bbr->rc_inp;
978 	if (rsm == NULL) {
979 		/* Nothing outstanding? */
980 		if (tp->t_flags & TF_DELACK) {
981 			if (tmr_up == PACE_TMR_DELACK)
982 				/*
983 				 * We are supposed to have delayed ack up
984 				 * and we do
985 				 */
986 				return;
987 		} else if (sbavail(&inp->inp_socket->so_snd) &&
988 		    (tmr_up == PACE_TMR_RXT)) {
989 			/*
990 			 * if we hit enobufs then we would expect the
991 			 * possiblity of nothing outstanding and the RXT up
992 			 * (and the hptsi timer).
993 			 */
994 			return;
995 		} else if (((V_tcp_always_keepalive ||
996 			    inp->inp_socket->so_options & SO_KEEPALIVE) &&
997 			    (tp->t_state <= TCPS_CLOSING)) &&
998 			    (tmr_up == PACE_TMR_KEEP) &&
999 		    (tp->snd_max == tp->snd_una)) {
1000 			/* We should have keep alive up and we do */
1001 			return;
1002 		}
1003 	}
1004 	if (rsm && (rsm->r_flags & BBR_SACK_PASSED)) {
1005 		if ((tp->t_flags & TF_SENTFIN) &&
1006 		    ((tp->snd_max - tp->snd_una) == 1) &&
1007 		    (rsm->r_flags & BBR_HAS_FIN)) {
1008 			/* needs to be a RXT */
1009 			if (tmr_up == PACE_TMR_RXT)
1010 				return;
1011 			else
1012 				goto wrong_timer;
1013 		} else if (tmr_up == PACE_TMR_RACK)
1014 			return;
1015 		else
1016 			goto wrong_timer;
1017 	} else if (rsm && (tmr_up == PACE_TMR_RACK)) {
1018 		/* Rack timer has priority if we have data out */
1019 		return;
1020 	} else if (SEQ_GT(tp->snd_max, tp->snd_una) &&
1021 		    ((tmr_up == PACE_TMR_TLP) ||
1022 	    (tmr_up == PACE_TMR_RXT))) {
1023 		/*
1024 		 * Either a TLP or RXT is fine if no sack-passed is in place
1025 		 * and data is outstanding.
1026 		 */
1027 		return;
1028 	} else if (tmr_up == PACE_TMR_DELACK) {
1029 		/*
1030 		 * If the delayed ack was going to go off before the
1031 		 * rtx/tlp/rack timer were going to expire, then that would
1032 		 * be the timer in control. Note we don't check the time
1033 		 * here trusting the code is correct.
1034 		 */
1035 		return;
1036 	}
1037 	if (SEQ_GT(tp->snd_max, tp->snd_una) &&
1038 	    ((tmr_up == PACE_TMR_RXT) ||
1039 	     (tmr_up == PACE_TMR_TLP) ||
1040 	     (tmr_up == PACE_TMR_RACK))) {
1041 		/*
1042 		 * We have outstanding data and
1043 		 * we *do* have a RACK, TLP or RXT
1044 		 * timer running. We won't restart
1045 		 * anything here since thats probably ok we
1046 		 * will get called with some timer here shortly.
1047 		 */
1048 		return;
1049 	}
1050 	/*
1051 	 * Ok the timer originally started is not what we want now. We will
1052 	 * force the hpts to be stopped if any, and restart with the slot
1053 	 * set to what was in the saved slot.
1054 	 */
1055 wrong_timer:
1056 	if ((bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0) {
1057 		if (inp->inp_in_hpts)
1058 			tcp_hpts_remove(inp, HPTS_REMOVE_OUTPUT);
1059 		bbr_timer_cancel(bbr, __LINE__, cts);
1060 		bbr_start_hpts_timer(bbr, tp, cts, 1, bbr->r_ctl.rc_last_delay_val,
1061 		    0);
1062 	} else {
1063 		/*
1064 		 * Output is hptsi so we just need to switch the type of
1065 		 * timer. We don't bother with keep-alive, since when we
1066 		 * jump through the output, it will start the keep-alive if
1067 		 * nothing is sent.
1068 		 *
1069 		 * We only need a delayed-ack added and or the hpts_timeout.
1070 		 */
1071 		hpts_timeout = bbr_timer_start(tp, bbr, cts);
1072 		if (tp->t_flags & TF_DELACK) {
1073 			if (hpts_timeout == 0) {
1074 				hpts_timeout = bbr_delack_time;
1075 				bbr->r_ctl.rc_hpts_flags = PACE_TMR_DELACK;
1076 			}
1077 			else if (hpts_timeout > bbr_delack_time) {
1078 				hpts_timeout = bbr_delack_time;
1079 				bbr->r_ctl.rc_hpts_flags = PACE_TMR_DELACK;
1080 			}
1081 		}
1082 		if (hpts_timeout) {
1083 			if (hpts_timeout > 0x7ffffffe)
1084 				hpts_timeout = 0x7ffffffe;
1085 			bbr->r_ctl.rc_timer_exp = cts + hpts_timeout;
1086 		}
1087 	}
1088 }
1089 
1090 int32_t bbr_clear_lost = 0;
1091 
1092 /*
1093  * Considers the two time values now (cts) and earlier.
1094  * If cts is smaller than earlier, we could have
1095  * had a sequence wrap (our counter wraps every
1096  * 70 min or so) or it could be just clock skew
1097  * getting us two differnt time values. Clock skew
1098  * will show up within 10ms or so. So in such
1099  * a case (where cts is behind earlier time by
1100  * less than 10ms) we return 0. Otherwise we
1101  * return the true difference between them.
1102  */
1103 static inline uint32_t
1104 bbr_calc_time(uint32_t cts, uint32_t earlier_time) {
1105 	/*
1106 	 * Given two timestamps, the current time stamp cts, and some other
1107 	 * time-stamp taken in theory earlier return the difference. The
1108 	 * trick is here sometimes locking will get the other timestamp
1109 	 * after the cts. If this occurs we need to return 0.
1110 	 */
1111 	if (TSTMP_GEQ(cts, earlier_time))
1112 		return (cts - earlier_time);
1113 	/*
1114 	 * cts is behind earlier_time if its less than 10ms consider it 0.
1115 	 * If its more than 10ms difference then we had a time wrap. Else
1116 	 * its just the normal locking foo. I wonder if we should not go to
1117 	 * 64bit TS and get rid of this issue.
1118 	 */
1119 	if (TSTMP_GEQ((cts + 10000), earlier_time))
1120 		return (0);
1121 	/*
1122 	 * Ok the time must have wrapped. So we need to answer a large
1123 	 * amount of time, which the normal subtraction should do.
1124 	 */
1125 	return (cts - earlier_time);
1126 }
1127 
1128 static int
1129 sysctl_bbr_clear_lost(SYSCTL_HANDLER_ARGS)
1130 {
1131 	uint32_t stat;
1132 	int32_t error;
1133 
1134 	error = SYSCTL_OUT(req, &bbr_clear_lost, sizeof(uint32_t));
1135 	if (error || req->newptr == NULL)
1136 		return error;
1137 
1138 	error = SYSCTL_IN(req, &stat, sizeof(uint32_t));
1139 	if (error)
1140 		return (error);
1141 	if (stat == 1) {
1142 #ifdef BBR_INVARIANTS
1143 		printf("Clearing BBR lost counters\n");
1144 #endif
1145 		COUNTER_ARRAY_ZERO(bbr_state_lost, BBR_MAX_STAT);
1146 		COUNTER_ARRAY_ZERO(bbr_state_time, BBR_MAX_STAT);
1147 		COUNTER_ARRAY_ZERO(bbr_state_resend, BBR_MAX_STAT);
1148 	} else if (stat == 2) {
1149 #ifdef BBR_INVARIANTS
1150 		printf("Clearing BBR option counters\n");
1151 #endif
1152 		COUNTER_ARRAY_ZERO(bbr_opts_arry, BBR_OPTS_SIZE);
1153 	} else if (stat == 3) {
1154 #ifdef BBR_INVARIANTS
1155 		printf("Clearing BBR stats counters\n");
1156 #endif
1157 		COUNTER_ARRAY_ZERO(bbr_stat_arry, BBR_STAT_SIZE);
1158 	} else if (stat == 4) {
1159 #ifdef BBR_INVARIANTS
1160 		printf("Clearing BBR out-size counters\n");
1161 #endif
1162 		COUNTER_ARRAY_ZERO(bbr_out_size, TCP_MSS_ACCT_SIZE);
1163 	}
1164 	bbr_clear_lost = 0;
1165 	return (0);
1166 }
1167 
1168 static void
1169 bbr_init_sysctls(void)
1170 {
1171 	struct sysctl_oid *bbr_probertt;
1172 	struct sysctl_oid *bbr_hptsi;
1173 	struct sysctl_oid *bbr_measure;
1174 	struct sysctl_oid *bbr_cwnd;
1175 	struct sysctl_oid *bbr_timeout;
1176 	struct sysctl_oid *bbr_states;
1177 	struct sysctl_oid *bbr_startup;
1178 	struct sysctl_oid *bbr_policer;
1179 
1180 	/* Probe rtt controls */
1181 	bbr_probertt = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1182 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1183 	    OID_AUTO,
1184 	    "probertt",
1185 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1186 	    "");
1187 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1188 	    SYSCTL_CHILDREN(bbr_probertt),
1189 	    OID_AUTO, "gain", CTLFLAG_RW,
1190 	    &bbr_rttprobe_gain, 192,
1191 	    "What is the filter gain drop in probe_rtt (0=disable)?");
1192 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1193 	    SYSCTL_CHILDREN(bbr_probertt),
1194 	    OID_AUTO, "cwnd", CTLFLAG_RW,
1195 	    &bbr_rtt_probe_cwndtarg, 4,
1196 	    "How many mss's are outstanding during probe-rtt");
1197 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1198 	    SYSCTL_CHILDREN(bbr_probertt),
1199 	    OID_AUTO, "int", CTLFLAG_RW,
1200 	    &bbr_rtt_probe_limit, 4000000,
1201 	    "If RTT has not shrank in this many micro-seconds enter probe-rtt");
1202 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1203 	    SYSCTL_CHILDREN(bbr_probertt),
1204 	    OID_AUTO, "mintime", CTLFLAG_RW,
1205 	    &bbr_rtt_probe_time, 200000,
1206 	    "How many microseconds in probe-rtt");
1207 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1208 	    SYSCTL_CHILDREN(bbr_probertt),
1209 	    OID_AUTO, "filter_len_sec", CTLFLAG_RW,
1210 	    &bbr_filter_len_sec, 6,
1211 	    "How long in seconds does the rttProp filter run?");
1212 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1213 	    SYSCTL_CHILDREN(bbr_probertt),
1214 	    OID_AUTO, "drain_rtt", CTLFLAG_RW,
1215 	    &bbr_drain_rtt, BBR_SRTT,
1216 	    "What is the drain rtt to use in probeRTT (rtt_prop=0, rtt_rack=1, rtt_pkt=2, rtt_srtt=3?");
1217 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1218 	    SYSCTL_CHILDREN(bbr_probertt),
1219 	    OID_AUTO, "can_force", CTLFLAG_RW,
1220 	    &bbr_can_force_probertt, 0,
1221 	    "If we keep setting new low rtt's but delay going in probe-rtt can we force in??");
1222 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1223 	    SYSCTL_CHILDREN(bbr_probertt),
1224 	    OID_AUTO, "enter_sets_force", CTLFLAG_RW,
1225 	    &bbr_probertt_sets_rtt, 0,
1226 	    "In NF mode, do we imitate google_mode and set the rttProp on entry to probe-rtt?");
1227 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1228 	    SYSCTL_CHILDREN(bbr_probertt),
1229 	    OID_AUTO, "can_adjust", CTLFLAG_RW,
1230 	    &bbr_can_adjust_probertt, 1,
1231 	    "Can we dynamically adjust the probe-rtt limits and times?");
1232 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1233 	    SYSCTL_CHILDREN(bbr_probertt),
1234 	    OID_AUTO, "is_ratio", CTLFLAG_RW,
1235 	    &bbr_is_ratio, 0,
1236 	    "is the limit to filter a ratio?");
1237 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1238 	    SYSCTL_CHILDREN(bbr_probertt),
1239 	    OID_AUTO, "use_cwnd", CTLFLAG_RW,
1240 	    &bbr_prtt_slam_cwnd, 0,
1241 	    "Should we set/recover cwnd?");
1242 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1243 	    SYSCTL_CHILDREN(bbr_probertt),
1244 	    OID_AUTO, "can_use_ts", CTLFLAG_RW,
1245 	    &bbr_can_use_ts_for_rtt, 1,
1246 	    "Can we use the ms timestamp if available for retransmistted rtt calculations?");
1247 
1248 	/* Pacing controls */
1249 	bbr_hptsi = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1250 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1251 	    OID_AUTO,
1252 	    "pacing",
1253 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1254 	    "");
1255 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1256 	    SYSCTL_CHILDREN(bbr_hptsi),
1257 	    OID_AUTO, "hw_pacing", CTLFLAG_RW,
1258 	    &bbr_allow_hdwr_pacing, 1,
1259 	    "Do we allow hardware pacing?");
1260 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1261 	    SYSCTL_CHILDREN(bbr_hptsi),
1262 	    OID_AUTO, "hw_pacing_limit", CTLFLAG_RW,
1263 	    &bbr_hardware_pacing_limit, 4000,
1264 	    "Do we have a limited number of connections for pacing chelsio (0=no limit)?");
1265 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1266 	    SYSCTL_CHILDREN(bbr_hptsi),
1267 	    OID_AUTO, "hw_pacing_adj", CTLFLAG_RW,
1268 	    &bbr_hdwr_pace_adjust, 2,
1269 	    "Multiplier to calculated tso size?");
1270 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1271 	    SYSCTL_CHILDREN(bbr_hptsi),
1272 	    OID_AUTO, "hw_pacing_floor", CTLFLAG_RW,
1273 	    &bbr_hdwr_pace_floor, 1,
1274 	    "Do we invoke the hardware pacing floor?");
1275 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1276 	    SYSCTL_CHILDREN(bbr_hptsi),
1277 	    OID_AUTO, "hw_pacing_delay_cnt", CTLFLAG_RW,
1278 	    &bbr_hdwr_pacing_delay_cnt, 10,
1279 	    "How many packets must be sent after hdwr pacing is enabled");
1280 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1281 	    SYSCTL_CHILDREN(bbr_hptsi),
1282 	    OID_AUTO, "bw_cross", CTLFLAG_RW,
1283 	    &bbr_cross_over, 3000000,
1284 	    "What is the point where we cross over to linux like TSO size set");
1285 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1286 	    SYSCTL_CHILDREN(bbr_hptsi),
1287 	    OID_AUTO, "seg_deltarg", CTLFLAG_RW,
1288 	    &bbr_hptsi_segments_delay_tar, 7000,
1289 	    "What is the worse case delay target for hptsi < 48Mbp connections");
1290 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1291 	    SYSCTL_CHILDREN(bbr_hptsi),
1292 	    OID_AUTO, "enet_oh", CTLFLAG_RW,
1293 	    &bbr_include_enet_oh, 0,
1294 	    "Do we include the ethernet overhead in calculating pacing delay?");
1295 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1296 	    SYSCTL_CHILDREN(bbr_hptsi),
1297 	    OID_AUTO, "ip_oh", CTLFLAG_RW,
1298 	    &bbr_include_ip_oh, 1,
1299 	    "Do we include the IP overhead in calculating pacing delay?");
1300 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1301 	    SYSCTL_CHILDREN(bbr_hptsi),
1302 	    OID_AUTO, "tcp_oh", CTLFLAG_RW,
1303 	    &bbr_include_tcp_oh, 0,
1304 	    "Do we include the TCP overhead in calculating pacing delay?");
1305 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1306 	    SYSCTL_CHILDREN(bbr_hptsi),
1307 	    OID_AUTO, "google_discount", CTLFLAG_RW,
1308 	    &bbr_google_discount, 10,
1309 	    "What is the default google discount percentage wise for pacing (11 = 1.1%%)?");
1310 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1311 	    SYSCTL_CHILDREN(bbr_hptsi),
1312 	    OID_AUTO, "all_get_min", CTLFLAG_RW,
1313 	    &bbr_all_get_min, 0,
1314 	    "If you are less than a MSS do you just get the min?");
1315 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1316 	    SYSCTL_CHILDREN(bbr_hptsi),
1317 	    OID_AUTO, "tso_min", CTLFLAG_RW,
1318 	    &bbr_hptsi_bytes_min, 1460,
1319 	    "For 0 -> 24Mbps what is floor number of segments for TSO");
1320 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1321 	    SYSCTL_CHILDREN(bbr_hptsi),
1322 	    OID_AUTO, "seg_tso_max", CTLFLAG_RW,
1323 	    &bbr_hptsi_segments_max, 6,
1324 	    "For 0 -> 24Mbps what is top number of segments for TSO");
1325 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1326 	    SYSCTL_CHILDREN(bbr_hptsi),
1327 	    OID_AUTO, "seg_floor", CTLFLAG_RW,
1328 	    &bbr_hptsi_segments_floor, 1,
1329 	    "Minimum TSO size we will fall too in segments");
1330 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1331 	    SYSCTL_CHILDREN(bbr_hptsi),
1332 	    OID_AUTO, "utter_max", CTLFLAG_RW,
1333 	    &bbr_hptsi_utter_max, 0,
1334 	    "The absolute maximum that any pacing (outside of hardware) can be");
1335 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1336 	    SYSCTL_CHILDREN(bbr_hptsi),
1337 	    OID_AUTO, "seg_divisor", CTLFLAG_RW,
1338 	    &bbr_hptsi_per_second, 100,
1339 	    "What is the divisor in our hptsi TSO calculation 512Mbps < X > 24Mbps ");
1340 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1341 	    SYSCTL_CHILDREN(bbr_hptsi),
1342 	    OID_AUTO, "srtt_mul", CTLFLAG_RW,
1343 	    &bbr_hptsi_max_mul, 1,
1344 	    "The multiplier for pace len max");
1345 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1346 	    SYSCTL_CHILDREN(bbr_hptsi),
1347 	    OID_AUTO, "srtt_div", CTLFLAG_RW,
1348 	    &bbr_hptsi_max_div, 2,
1349 	    "The divisor for pace len max");
1350 	/* Measurement controls */
1351 	bbr_measure = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1352 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1353 	    OID_AUTO,
1354 	    "measure",
1355 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1356 	    "Measurement controls");
1357 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1358 	    SYSCTL_CHILDREN(bbr_measure),
1359 	    OID_AUTO, "min_i_bw", CTLFLAG_RW,
1360 	    &bbr_initial_bw_bps, 62500,
1361 	    "Minimum initial b/w in bytes per second");
1362 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1363 	    SYSCTL_CHILDREN(bbr_measure),
1364 	    OID_AUTO, "no_sack_needed", CTLFLAG_RW,
1365 	    &bbr_sack_not_required, 0,
1366 	    "Do we allow bbr to run on connections not supporting SACK?");
1367 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1368 	    SYSCTL_CHILDREN(bbr_measure),
1369 	    OID_AUTO, "use_google", CTLFLAG_RW,
1370 	    &bbr_use_google_algo, 0,
1371 	    "Use has close to google V1.0 has possible?");
1372 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1373 	    SYSCTL_CHILDREN(bbr_measure),
1374 	    OID_AUTO, "ts_limiting", CTLFLAG_RW,
1375 	    &bbr_ts_limiting, 1,
1376 	    "Do we attempt to use the peers timestamp to limit b/w caculations?");
1377 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1378 	    SYSCTL_CHILDREN(bbr_measure),
1379 	    OID_AUTO, "ts_can_raise", CTLFLAG_RW,
1380 	    &bbr_ts_can_raise, 0,
1381 	    "Can we raise the b/w via timestamp b/w calculation?");
1382 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1383 	    SYSCTL_CHILDREN(bbr_measure),
1384 	    OID_AUTO, "ts_delta", CTLFLAG_RW,
1385 	    &bbr_min_usec_delta, 20000,
1386 	    "How long in usec between ts of our sends in ts validation code?");
1387 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1388 	    SYSCTL_CHILDREN(bbr_measure),
1389 	    OID_AUTO, "ts_peer_delta", CTLFLAG_RW,
1390 	    &bbr_min_peer_delta, 20,
1391 	    "What min numerical value should be between the peer deltas?");
1392 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1393 	    SYSCTL_CHILDREN(bbr_measure),
1394 	    OID_AUTO, "ts_delta_percent", CTLFLAG_RW,
1395 	    &bbr_delta_percent, 150,
1396 	    "What percentage (150 = 15.0) do we allow variance for?");
1397 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1398 	    SYSCTL_CHILDREN(bbr_measure),
1399 	    OID_AUTO, "min_measure_good_bw", CTLFLAG_RW,
1400 	    &bbr_min_measurements_req, 1,
1401 	    "What is the minimum measurment count we need before we switch to our b/w estimate");
1402 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1403 	    SYSCTL_CHILDREN(bbr_measure),
1404 	    OID_AUTO, "min_measure_before_pace", CTLFLAG_RW,
1405 	    &bbr_no_pacing_until, 4,
1406 	    "How many pkt-epoch's (0 is off) do we need before pacing is on?");
1407 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1408 	    SYSCTL_CHILDREN(bbr_measure),
1409 	    OID_AUTO, "quanta", CTLFLAG_RW,
1410 	    &bbr_quanta, 2,
1411 	    "Extra quanta to add when calculating the target (ID section 4.2.3.2).");
1412 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1413 	    SYSCTL_CHILDREN(bbr_measure),
1414 	    OID_AUTO, "noretran", CTLFLAG_RW,
1415 	    &bbr_no_retran, 0,
1416 	    "Should google mode not use retransmission measurements for the b/w estimation?");
1417 	/* State controls */
1418 	bbr_states = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1419 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1420 	    OID_AUTO,
1421 	    "states",
1422 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1423 	    "State controls");
1424 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1425 	    SYSCTL_CHILDREN(bbr_states),
1426 	    OID_AUTO, "idle_restart", CTLFLAG_RW,
1427 	    &bbr_uses_idle_restart, 0,
1428 	    "Do we use a new special idle_restart state to ramp back up quickly?");
1429 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1430 	    SYSCTL_CHILDREN(bbr_states),
1431 	    OID_AUTO, "idle_restart_threshold", CTLFLAG_RW,
1432 	    &bbr_idle_restart_threshold, 100000,
1433 	    "How long must we be idle before we restart??");
1434 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1435 	    SYSCTL_CHILDREN(bbr_states),
1436 	    OID_AUTO, "use_pkt_epoch", CTLFLAG_RW,
1437 	    &bbr_state_is_pkt_epoch, 0,
1438 	    "Do we use a pkt-epoch for substate if 0 rttProp?");
1439 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1440 	    SYSCTL_CHILDREN(bbr_states),
1441 	    OID_AUTO, "startup_rtt_gain", CTLFLAG_RW,
1442 	    &bbr_rtt_gain_thresh, 0,
1443 	    "What increase in RTT triggers us to stop ignoring no-loss and possibly exit startup?");
1444 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1445 	    SYSCTL_CHILDREN(bbr_states),
1446 	    OID_AUTO, "drain_floor", CTLFLAG_RW,
1447 	    &bbr_drain_floor, 88,
1448 	    "What is the lowest we can drain (pg) too?");
1449 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1450 	    SYSCTL_CHILDREN(bbr_states),
1451 	    OID_AUTO, "drain_2_target", CTLFLAG_RW,
1452 	    &bbr_state_drain_2_tar, 1,
1453 	    "Do we drain to target in drain substate?");
1454 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1455 	    SYSCTL_CHILDREN(bbr_states),
1456 	    OID_AUTO, "gain_2_target", CTLFLAG_RW,
1457 	    &bbr_gain_to_target, 1,
1458 	    "Does probe bw gain to target??");
1459 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1460 	    SYSCTL_CHILDREN(bbr_states),
1461 	    OID_AUTO, "gain_extra_time", CTLFLAG_RW,
1462 	    &bbr_gain_gets_extra_too, 1,
1463 	    "Does probe bw gain get the extra time too?");
1464 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1465 	    SYSCTL_CHILDREN(bbr_states),
1466 	    OID_AUTO, "ld_div", CTLFLAG_RW,
1467 	    &bbr_drain_drop_div, 5,
1468 	    "Long drain drop divider?");
1469 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1470 	    SYSCTL_CHILDREN(bbr_states),
1471 	    OID_AUTO, "ld_mul", CTLFLAG_RW,
1472 	    &bbr_drain_drop_mul, 4,
1473 	    "Long drain drop multiplier?");
1474 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1475 	    SYSCTL_CHILDREN(bbr_states),
1476 	    OID_AUTO, "rand_ot_disc", CTLFLAG_RW,
1477 	    &bbr_rand_ot, 50,
1478 	    "Random discount of the ot?");
1479 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1480 	    SYSCTL_CHILDREN(bbr_states),
1481 	    OID_AUTO, "dr_filter_life", CTLFLAG_RW,
1482 	    &bbr_num_pktepo_for_del_limit, BBR_NUM_RTTS_FOR_DEL_LIMIT,
1483 	    "How many packet-epochs does the b/w delivery rate last?");
1484 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1485 	    SYSCTL_CHILDREN(bbr_states),
1486 	    OID_AUTO, "subdrain_applimited", CTLFLAG_RW,
1487 	    &bbr_sub_drain_app_limit, 0,
1488 	    "Does our sub-state drain invoke app limited if its long?");
1489 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1490 	    SYSCTL_CHILDREN(bbr_states),
1491 	    OID_AUTO, "use_cwnd_subdrain", CTLFLAG_RW,
1492 	    &bbr_sub_drain_slam_cwnd, 0,
1493 	    "Should we set/recover cwnd for sub-state drain?");
1494 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1495 	    SYSCTL_CHILDREN(bbr_states),
1496 	    OID_AUTO, "use_cwnd_maindrain", CTLFLAG_RW,
1497 	    &bbr_slam_cwnd_in_main_drain, 0,
1498 	    "Should we set/recover cwnd for main-state drain?");
1499 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1500 	    SYSCTL_CHILDREN(bbr_states),
1501 	    OID_AUTO, "google_gets_earlyout", CTLFLAG_RW,
1502 	    &google_allow_early_out, 1,
1503 	    "Should we allow google probe-bw/drain to exit early at flight target?");
1504 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1505 	    SYSCTL_CHILDREN(bbr_states),
1506 	    OID_AUTO, "google_exit_loss", CTLFLAG_RW,
1507 	    &google_consider_lost, 1,
1508 	    "Should we have losses exit gain of probebw in google mode??");
1509 	/* Startup controls */
1510 	bbr_startup = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1511 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1512 	    OID_AUTO,
1513 	    "startup",
1514 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1515 	    "Startup controls");
1516 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1517 	    SYSCTL_CHILDREN(bbr_startup),
1518 	    OID_AUTO, "cheat_iwnd", CTLFLAG_RW,
1519 	    &bbr_sends_full_iwnd, 1,
1520 	    "Do we not pace but burst out initial windows has our TSO size?");
1521 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1522 	    SYSCTL_CHILDREN(bbr_startup),
1523 	    OID_AUTO, "loss_threshold", CTLFLAG_RW,
1524 	    &bbr_startup_loss_thresh, 2000,
1525 	    "In startup what is the loss threshold in a pe that will exit us from startup?");
1526 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1527 	    SYSCTL_CHILDREN(bbr_startup),
1528 	    OID_AUTO, "use_lowerpg", CTLFLAG_RW,
1529 	    &bbr_use_lower_gain_in_startup, 1,
1530 	    "Should we use a lower hptsi gain if we see loss in startup?");
1531 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1532 	    SYSCTL_CHILDREN(bbr_startup),
1533 	    OID_AUTO, "gain", CTLFLAG_RW,
1534 	    &bbr_start_exit, 25,
1535 	    "What gain percent do we need to see to stay in startup??");
1536 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1537 	    SYSCTL_CHILDREN(bbr_startup),
1538 	    OID_AUTO, "low_gain", CTLFLAG_RW,
1539 	    &bbr_low_start_exit, 15,
1540 	    "What gain percent do we need to see to stay in the lower gain startup??");
1541 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1542 	    SYSCTL_CHILDREN(bbr_startup),
1543 	    OID_AUTO, "loss_exit", CTLFLAG_RW,
1544 	    &bbr_exit_startup_at_loss, 1,
1545 	    "Should we exit startup at loss in an epoch if we are not gaining?");
1546 	/* CWND controls */
1547 	bbr_cwnd = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1548 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1549 	    OID_AUTO,
1550 	    "cwnd",
1551 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1552 	    "Cwnd controls");
1553 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1554 	    SYSCTL_CHILDREN(bbr_cwnd),
1555 	    OID_AUTO, "tar_rtt", CTLFLAG_RW,
1556 	    &bbr_cwndtarget_rtt_touse, 0,
1557 	    "Target cwnd rtt measurment to use (0=rtt_prop, 1=rtt_rack, 2=pkt_rtt, 3=srtt)?");
1558 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1559 	    SYSCTL_CHILDREN(bbr_cwnd),
1560 	    OID_AUTO, "may_shrink", CTLFLAG_RW,
1561 	    &bbr_cwnd_may_shrink, 0,
1562 	    "Can the cwnd shrink if it would grow to more than the target?");
1563 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1564 	    SYSCTL_CHILDREN(bbr_cwnd),
1565 	    OID_AUTO, "max_target_limit", CTLFLAG_RW,
1566 	    &bbr_target_cwnd_mult_limit, 8,
1567 	    "Do we limit the cwnd to some multiple of the cwnd target if cwnd can't shrink 0=no?");
1568 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1569 	    SYSCTL_CHILDREN(bbr_cwnd),
1570 	    OID_AUTO, "highspeed_min", CTLFLAG_RW,
1571 	    &bbr_cwnd_min_val_hs, BBR_HIGHSPEED_NUM_MSS,
1572 	    "What is the high-speed min cwnd (rttProp under 1ms)");
1573 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1574 	    SYSCTL_CHILDREN(bbr_cwnd),
1575 	    OID_AUTO, "lowspeed_min", CTLFLAG_RW,
1576 	    &bbr_cwnd_min_val, BBR_PROBERTT_NUM_MSS,
1577 	    "What is the min cwnd (rttProp > 1ms)");
1578 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1579 	    SYSCTL_CHILDREN(bbr_cwnd),
1580 	    OID_AUTO, "initwin", CTLFLAG_RW,
1581 	    &bbr_def_init_win, 10,
1582 	    "What is the BBR initial window, if 0 use tcp version");
1583 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1584 	    SYSCTL_CHILDREN(bbr_cwnd),
1585 	    OID_AUTO, "do_loss_red", CTLFLAG_RW,
1586 	    &bbr_do_red, 600,
1587 	    "Do we reduce the b/w at exit from recovery based on ratio of prop/srtt (800=80.0, 0=off)?");
1588 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1589 	    SYSCTL_CHILDREN(bbr_cwnd),
1590 	    OID_AUTO, "red_scale", CTLFLAG_RW,
1591 	    &bbr_red_scale, 20000,
1592 	    "What RTT do we scale with?");
1593 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1594 	    SYSCTL_CHILDREN(bbr_cwnd),
1595 	    OID_AUTO, "red_growslow", CTLFLAG_RW,
1596 	    &bbr_red_growth_restrict, 1,
1597 	    "Do we restrict cwnd growth for whats in flight?");
1598 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1599 	    SYSCTL_CHILDREN(bbr_cwnd),
1600 	    OID_AUTO, "red_div", CTLFLAG_RW,
1601 	    &bbr_red_div, 2,
1602 	    "If we reduce whats the divisor?");
1603 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1604 	    SYSCTL_CHILDREN(bbr_cwnd),
1605 	    OID_AUTO, "red_mul", CTLFLAG_RW,
1606 	    &bbr_red_mul, 1,
1607 	    "If we reduce whats the mulitiplier?");
1608 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1609 	    SYSCTL_CHILDREN(bbr_cwnd),
1610 	    OID_AUTO, "target_is_unit", CTLFLAG_RW,
1611 	    &bbr_target_is_bbunit, 0,
1612 	    "Is the state target the pacing_gain or BBR_UNIT?");
1613 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1614 	    SYSCTL_CHILDREN(bbr_cwnd),
1615 	    OID_AUTO, "drop_limit", CTLFLAG_RW,
1616 	    &bbr_drop_limit, 0,
1617 	    "Number of segments limit for drop (0=use min_cwnd w/flight)?");
1618 
1619         /* Timeout controls */
1620 	bbr_timeout = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1621 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1622 	    OID_AUTO,
1623 	    "timeout",
1624 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1625 	    "Time out controls");
1626 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1627 	    SYSCTL_CHILDREN(bbr_timeout),
1628 	    OID_AUTO, "delack", CTLFLAG_RW,
1629 	    &bbr_delack_time, 100000,
1630 	    "BBR's delayed ack time");
1631 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1632 	    SYSCTL_CHILDREN(bbr_timeout),
1633 	    OID_AUTO, "tlp_uses", CTLFLAG_RW,
1634 	    &bbr_tlp_type_to_use, 3,
1635 	    "RTT that TLP uses in its calculations, 0=rttProp, 1=Rack_rtt, 2=pkt_rtt and 3=srtt");
1636 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1637 	    SYSCTL_CHILDREN(bbr_timeout),
1638 	    OID_AUTO, "persmin", CTLFLAG_RW,
1639 	    &bbr_persist_min, 250000,
1640 	    "What is the minimum time in microseconds between persists");
1641 	SYSCTL_ADD_U32(&bbr_sysctl_ctx,
1642 	    SYSCTL_CHILDREN(bbr_timeout),
1643 	    OID_AUTO, "persmax", CTLFLAG_RW,
1644 	    &bbr_persist_max, 1000000,
1645 	    "What is the largest delay in microseconds between persists");
1646 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1647 	    SYSCTL_CHILDREN(bbr_timeout),
1648 	    OID_AUTO, "tlp_minto", CTLFLAG_RW,
1649 	    &bbr_tlp_min, 10000,
1650 	    "TLP Min timeout in usecs");
1651 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1652 	    SYSCTL_CHILDREN(bbr_timeout),
1653 	    OID_AUTO, "tlp_dack_time", CTLFLAG_RW,
1654 	    &bbr_delayed_ack_time, 200000,
1655 	    "TLP delayed ack compensation value");
1656 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1657 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1658 	    OID_AUTO, "minrto", CTLFLAG_RW,
1659 	    &bbr_rto_min_ms, 30,
1660 	    "Minimum RTO in ms");
1661 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1662 	    SYSCTL_CHILDREN(bbr_timeout),
1663 	    OID_AUTO, "maxrto", CTLFLAG_RW,
1664 	    &bbr_rto_max_sec, 4,
1665 	    "Maxiumum RTO in seconds -- should be at least as large as min_rto");
1666 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1667 	    SYSCTL_CHILDREN(bbr_timeout),
1668 	    OID_AUTO, "tlp_retry", CTLFLAG_RW,
1669 	    &bbr_tlp_max_resend, 2,
1670 	    "How many times does TLP retry a single segment or multiple with no ACK");
1671 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1672 	    SYSCTL_CHILDREN(bbr_timeout),
1673 	    OID_AUTO, "minto", CTLFLAG_RW,
1674 	    &bbr_min_to, 1000,
1675 	    "Minimum rack timeout in useconds");
1676 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1677 	    SYSCTL_CHILDREN(bbr_timeout),
1678 	    OID_AUTO, "pktdelay", CTLFLAG_RW,
1679 	    &bbr_pkt_delay, 1000,
1680 	    "Extra RACK time (in useconds) besides reordering thresh");
1681 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1682 	    SYSCTL_CHILDREN(bbr_timeout),
1683 	    OID_AUTO, "incr_tmrs", CTLFLAG_RW,
1684 	    &bbr_incr_timers, 1,
1685 	    "Increase the RXT/TLP timer by the pacing time used?");
1686 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1687 	    SYSCTL_CHILDREN(bbr_timeout),
1688 	    OID_AUTO, "rxtmark_sackpassed", CTLFLAG_RW,
1689 	    &bbr_marks_rxt_sack_passed, 0,
1690 	    "Mark sack passed on all those not ack'd when a RXT hits?");
1691 	/* Policer controls */
1692 	bbr_policer = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
1693 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1694 	    OID_AUTO,
1695 	    "policer",
1696 	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1697 	    "Policer controls");
1698 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1699 	    SYSCTL_CHILDREN(bbr_policer),
1700 	    OID_AUTO, "detect_enable", CTLFLAG_RW,
1701 	    &bbr_policer_detection_enabled, 1,
1702 	    "Is policer detection enabled??");
1703 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1704 	    SYSCTL_CHILDREN(bbr_policer),
1705 	    OID_AUTO, "min_pes", CTLFLAG_RW,
1706 	    &bbr_lt_intvl_min_rtts, 4,
1707 	    "Minimum number of PE's?");
1708 	SYSCTL_ADD_U64(&bbr_sysctl_ctx,
1709 	    SYSCTL_CHILDREN(bbr_policer),
1710 	    OID_AUTO, "bwdiff", CTLFLAG_RW,
1711 	    &bbr_lt_bw_diff, (4000/8),
1712 	    "Minimal bw diff?");
1713 	SYSCTL_ADD_U64(&bbr_sysctl_ctx,
1714 	    SYSCTL_CHILDREN(bbr_policer),
1715 	    OID_AUTO, "bwratio", CTLFLAG_RW,
1716 	    &bbr_lt_bw_ratio, 8,
1717 	    "Minimal bw diff?");
1718 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1719 	    SYSCTL_CHILDREN(bbr_policer),
1720 	    OID_AUTO, "from_rack_rxt", CTLFLAG_RW,
1721 	    &bbr_policer_call_from_rack_to, 0,
1722 	    "Do we call the policer detection code from a rack-timeout?");
1723 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1724 	    SYSCTL_CHILDREN(bbr_policer),
1725 	    OID_AUTO, "false_postive", CTLFLAG_RW,
1726 	    &bbr_lt_intvl_fp, 0,
1727 	    "What packet epoch do we do false-postive detection at (0=no)?");
1728 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1729 	    SYSCTL_CHILDREN(bbr_policer),
1730 	    OID_AUTO, "loss_thresh", CTLFLAG_RW,
1731 	    &bbr_lt_loss_thresh, 196,
1732 	    "Loss threshold 196 = 19.6%?");
1733 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1734 	    SYSCTL_CHILDREN(bbr_policer),
1735 	    OID_AUTO, "false_postive_thresh", CTLFLAG_RW,
1736 	    &bbr_lt_fd_thresh, 100,
1737 	    "What percentage is the false detection threshold (150=15.0)?");
1738 	/* All the rest */
1739 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1740 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1741 	    OID_AUTO, "cheat_rxt", CTLFLAG_RW,
1742 	    &bbr_use_rack_resend_cheat, 0,
1743 	    "Do we burst 1ms between sends on retransmissions (like rack)?");
1744 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1745 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1746 	    OID_AUTO, "error_paceout", CTLFLAG_RW,
1747 	    &bbr_error_base_paceout, 10000,
1748 	    "When we hit an error what is the min to pace out in usec's?");
1749 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1750 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1751 	    OID_AUTO, "kill_paceout", CTLFLAG_RW,
1752 	    &bbr_max_net_error_cnt, 10,
1753 	    "When we hit this many errors in a row, kill the session?");
1754 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1755 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1756 	    OID_AUTO, "data_after_close", CTLFLAG_RW,
1757 	    &bbr_ignore_data_after_close, 1,
1758 	    "Do we hold off sending a RST until all pending data is ack'd");
1759 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1760 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1761 	    OID_AUTO, "resend_use_tso", CTLFLAG_RW,
1762 	    &bbr_resends_use_tso, 0,
1763 	    "Can resends use TSO?");
1764 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1765 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1766 	    OID_AUTO, "sblklimit", CTLFLAG_RW,
1767 	    &bbr_sack_block_limit, 128,
1768 	    "When do we start ignoring small sack blocks");
1769 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1770 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1771 	    OID_AUTO, "bb_verbose", CTLFLAG_RW,
1772 	    &bbr_verbose_logging, 0,
1773 	    "Should BBR black box logging be verbose");
1774 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1775 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1776 	    OID_AUTO, "reorder_thresh", CTLFLAG_RW,
1777 	    &bbr_reorder_thresh, 2,
1778 	    "What factor for rack will be added when seeing reordering (shift right)");
1779 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1780 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1781 	    OID_AUTO, "reorder_fade", CTLFLAG_RW,
1782 	    &bbr_reorder_fade, 0,
1783 	    "Does reorder detection fade, if so how many ms (0 means never)");
1784 	SYSCTL_ADD_S32(&bbr_sysctl_ctx,
1785 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1786 	    OID_AUTO, "rtt_tlp_thresh", CTLFLAG_RW,
1787 	    &bbr_tlp_thresh, 1,
1788 	    "what divisor for TLP rtt/retran will be added (1=rtt, 2=1/2 rtt etc)");
1789 	/* Stats and counters */
1790 	/* The pacing counters for hdwr/software can't be in the array */
1791 	bbr_nohdwr_pacing_enobuf = counter_u64_alloc(M_WAITOK);
1792 	bbr_hdwr_pacing_enobuf = counter_u64_alloc(M_WAITOK);
1793 	SYSCTL_ADD_COUNTER_U64(&bbr_sysctl_ctx,
1794 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1795 	    OID_AUTO, "enob_hdwr_pacing", CTLFLAG_RD,
1796 	    &bbr_hdwr_pacing_enobuf,
1797 	    "Total number of enobufs for hardware paced flows");
1798 	SYSCTL_ADD_COUNTER_U64(&bbr_sysctl_ctx,
1799 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1800 	    OID_AUTO, "enob_no_hdwr_pacing", CTLFLAG_RD,
1801 	    &bbr_nohdwr_pacing_enobuf,
1802 	    "Total number of enobufs for non-hardware paced flows");
1803 
1804 	bbr_flows_whdwr_pacing = counter_u64_alloc(M_WAITOK);
1805 	SYSCTL_ADD_COUNTER_U64(&bbr_sysctl_ctx,
1806 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1807 	    OID_AUTO, "hdwr_pacing", CTLFLAG_RD,
1808 	    &bbr_flows_whdwr_pacing,
1809 	    "Total number of hardware paced flows");
1810 	bbr_flows_nohdwr_pacing = counter_u64_alloc(M_WAITOK);
1811 	SYSCTL_ADD_COUNTER_U64(&bbr_sysctl_ctx,
1812 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1813 	    OID_AUTO, "software_pacing", CTLFLAG_RD,
1814 	    &bbr_flows_nohdwr_pacing,
1815 	    "Total number of software paced flows");
1816 	COUNTER_ARRAY_ALLOC(bbr_stat_arry, BBR_STAT_SIZE, M_WAITOK);
1817 	SYSCTL_ADD_COUNTER_U64_ARRAY(&bbr_sysctl_ctx, SYSCTL_CHILDREN(bbr_sysctl_root),
1818 	    OID_AUTO, "stats", CTLFLAG_RD,
1819 	    bbr_stat_arry, BBR_STAT_SIZE, "BBR Stats");
1820 	COUNTER_ARRAY_ALLOC(bbr_opts_arry, BBR_OPTS_SIZE, M_WAITOK);
1821 	SYSCTL_ADD_COUNTER_U64_ARRAY(&bbr_sysctl_ctx, SYSCTL_CHILDREN(bbr_sysctl_root),
1822 	    OID_AUTO, "opts", CTLFLAG_RD,
1823 	    bbr_opts_arry, BBR_OPTS_SIZE, "BBR Option Stats");
1824 	COUNTER_ARRAY_ALLOC(bbr_state_lost, BBR_MAX_STAT, M_WAITOK);
1825 	SYSCTL_ADD_COUNTER_U64_ARRAY(&bbr_sysctl_ctx, SYSCTL_CHILDREN(bbr_sysctl_root),
1826 	    OID_AUTO, "lost", CTLFLAG_RD,
1827 	    bbr_state_lost, BBR_MAX_STAT, "Stats of when losses occur");
1828 	COUNTER_ARRAY_ALLOC(bbr_state_resend, BBR_MAX_STAT, M_WAITOK);
1829 	SYSCTL_ADD_COUNTER_U64_ARRAY(&bbr_sysctl_ctx, SYSCTL_CHILDREN(bbr_sysctl_root),
1830 	    OID_AUTO, "stateresend", CTLFLAG_RD,
1831 	    bbr_state_resend, BBR_MAX_STAT, "Stats of what states resend");
1832 	COUNTER_ARRAY_ALLOC(bbr_state_time, BBR_MAX_STAT, M_WAITOK);
1833 	SYSCTL_ADD_COUNTER_U64_ARRAY(&bbr_sysctl_ctx, SYSCTL_CHILDREN(bbr_sysctl_root),
1834 	    OID_AUTO, "statetime", CTLFLAG_RD,
1835 	    bbr_state_time, BBR_MAX_STAT, "Stats of time spent in the states");
1836 	COUNTER_ARRAY_ALLOC(bbr_out_size, TCP_MSS_ACCT_SIZE, M_WAITOK);
1837 	SYSCTL_ADD_COUNTER_U64_ARRAY(&bbr_sysctl_ctx, SYSCTL_CHILDREN(bbr_sysctl_root),
1838 	    OID_AUTO, "outsize", CTLFLAG_RD,
1839 	    bbr_out_size, TCP_MSS_ACCT_SIZE, "Size of output calls");
1840 	SYSCTL_ADD_PROC(&bbr_sysctl_ctx,
1841 	    SYSCTL_CHILDREN(bbr_sysctl_root),
1842 	    OID_AUTO, "clrlost", CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE,
1843 	    &bbr_clear_lost, 0, sysctl_bbr_clear_lost, "IU", "Clear lost counters");
1844 }
1845 
1846 static void
1847 bbr_counter_destroy(void)
1848 {
1849 	COUNTER_ARRAY_FREE(bbr_stat_arry, BBR_STAT_SIZE);
1850 	COUNTER_ARRAY_FREE(bbr_opts_arry, BBR_OPTS_SIZE);
1851 	COUNTER_ARRAY_FREE(bbr_out_size, TCP_MSS_ACCT_SIZE);
1852 	COUNTER_ARRAY_FREE(bbr_state_lost, BBR_MAX_STAT);
1853 	COUNTER_ARRAY_FREE(bbr_state_time, BBR_MAX_STAT);
1854 	COUNTER_ARRAY_FREE(bbr_state_resend, BBR_MAX_STAT);
1855 	counter_u64_free(bbr_nohdwr_pacing_enobuf);
1856 	counter_u64_free(bbr_hdwr_pacing_enobuf);
1857 	counter_u64_free(bbr_flows_whdwr_pacing);
1858 	counter_u64_free(bbr_flows_nohdwr_pacing);
1859 
1860 }
1861 
1862 static __inline void
1863 bbr_fill_in_logging_data(struct tcp_bbr *bbr, struct tcp_log_bbr *l, uint32_t cts)
1864 {
1865 	memset(l, 0, sizeof(union tcp_log_stackspecific));
1866 	l->cur_del_rate = bbr->r_ctl.rc_bbr_cur_del_rate;
1867 	l->delRate = get_filter_value(&bbr->r_ctl.rc_delrate);
1868 	l->rttProp = get_filter_value_small(&bbr->r_ctl.rc_rttprop);
1869 	l->bw_inuse = bbr_get_bw(bbr);
1870 	l->inflight = ctf_flight_size(bbr->rc_tp,
1871 			  (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
1872 	l->applimited = bbr->r_ctl.r_app_limited_until;
1873 	l->delivered = bbr->r_ctl.rc_delivered;
1874 	l->timeStamp = cts;
1875 	l->lost = bbr->r_ctl.rc_lost;
1876 	l->bbr_state = bbr->rc_bbr_state;
1877 	l->bbr_substate = bbr_state_val(bbr);
1878 	l->epoch = bbr->r_ctl.rc_rtt_epoch;
1879 	l->lt_epoch = bbr->r_ctl.rc_lt_epoch;
1880 	l->pacing_gain = bbr->r_ctl.rc_bbr_hptsi_gain;
1881 	l->cwnd_gain = bbr->r_ctl.rc_bbr_cwnd_gain;
1882 	l->inhpts = bbr->rc_inp->inp_in_hpts;
1883 	l->ininput = bbr->rc_inp->inp_in_input;
1884 	l->use_lt_bw = bbr->rc_lt_use_bw;
1885 	l->pkts_out = bbr->r_ctl.rc_flight_at_input;
1886 	l->pkt_epoch = bbr->r_ctl.rc_pkt_epoch;
1887 }
1888 
1889 static void
1890 bbr_log_type_bw_reduce(struct tcp_bbr *bbr, int reason)
1891 {
1892 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1893 		union tcp_log_stackspecific log;
1894 
1895 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
1896 		log.u_bbr.flex1 = 0;
1897 		log.u_bbr.flex2 = 0;
1898 		log.u_bbr.flex5 = 0;
1899 		log.u_bbr.flex3 = 0;
1900 		log.u_bbr.flex4 = bbr->r_ctl.rc_pkt_epoch_loss_rate;
1901 		log.u_bbr.flex7 = reason;
1902 		log.u_bbr.flex6 = bbr->r_ctl.rc_bbr_enters_probertt;
1903 		log.u_bbr.flex8 = 0;
1904 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
1905 		    &bbr->rc_inp->inp_socket->so_rcv,
1906 		    &bbr->rc_inp->inp_socket->so_snd,
1907 		    BBR_LOG_BW_RED_EV, 0,
1908 		    0, &log, false, &bbr->rc_tv);
1909 	}
1910 }
1911 
1912 static void
1913 bbr_log_type_rwnd_collapse(struct tcp_bbr *bbr, int seq, int mode, uint32_t count)
1914 {
1915 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1916 		union tcp_log_stackspecific log;
1917 
1918 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
1919 		log.u_bbr.flex1 = seq;
1920 		log.u_bbr.flex2 = count;
1921 		log.u_bbr.flex8 = mode;
1922 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
1923 		    &bbr->rc_inp->inp_socket->so_rcv,
1924 		    &bbr->rc_inp->inp_socket->so_snd,
1925 		    BBR_LOG_LOWGAIN, 0,
1926 		    0, &log, false, &bbr->rc_tv);
1927 	}
1928 }
1929 
1930 static void
1931 bbr_log_type_just_return(struct tcp_bbr *bbr, uint32_t cts, uint32_t tlen, uint8_t hpts_calling,
1932     uint8_t reason, uint32_t p_maxseg, int len)
1933 {
1934 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1935 		union tcp_log_stackspecific log;
1936 
1937 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
1938 		log.u_bbr.flex1 = p_maxseg;
1939 		log.u_bbr.flex2 = bbr->r_ctl.rc_hpts_flags;
1940 		log.u_bbr.flex3 = bbr->r_ctl.rc_timer_exp;
1941 		log.u_bbr.flex4 = reason;
1942 		log.u_bbr.flex5 = bbr->rc_in_persist;
1943 		log.u_bbr.flex6 = bbr->r_ctl.rc_last_delay_val;
1944 		log.u_bbr.flex7 = p_maxseg;
1945 		log.u_bbr.flex8 = bbr->rc_in_persist;
1946 		log.u_bbr.pkts_out = 0;
1947 		log.u_bbr.applimited = len;
1948 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
1949 		    &bbr->rc_inp->inp_socket->so_rcv,
1950 		    &bbr->rc_inp->inp_socket->so_snd,
1951 		    BBR_LOG_JUSTRET, 0,
1952 		    tlen, &log, false, &bbr->rc_tv);
1953 	}
1954 }
1955 
1956 static void
1957 bbr_log_type_enter_rec(struct tcp_bbr *bbr, uint32_t seq)
1958 {
1959 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1960 		union tcp_log_stackspecific log;
1961 
1962 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
1963 		log.u_bbr.flex1 = seq;
1964 		log.u_bbr.flex2 = bbr->r_ctl.rc_cwnd_on_ent;
1965 		log.u_bbr.flex3 = bbr->r_ctl.rc_recovery_start;
1966 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
1967 		    &bbr->rc_inp->inp_socket->so_rcv,
1968 		    &bbr->rc_inp->inp_socket->so_snd,
1969 		    BBR_LOG_ENTREC, 0,
1970 		    0, &log, false, &bbr->rc_tv);
1971 	}
1972 }
1973 
1974 static void
1975 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)
1976 {
1977 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
1978 		union tcp_log_stackspecific log;
1979 
1980 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
1981 		log.u_bbr.flex1 = tso;
1982 		log.u_bbr.flex2 = maxseg;
1983 		log.u_bbr.flex3 = mtu;
1984 		log.u_bbr.flex4 = csum_flags;
1985 		TCP_LOG_EVENTP(tp, NULL,
1986 		    &bbr->rc_inp->inp_socket->so_rcv,
1987 		    &bbr->rc_inp->inp_socket->so_snd,
1988 		    BBR_LOG_MSGSIZE, 0,
1989 		    0, &log, false, &bbr->rc_tv);
1990 	}
1991 }
1992 
1993 static void
1994 bbr_log_flowend(struct tcp_bbr *bbr)
1995 {
1996 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
1997 		union tcp_log_stackspecific log;
1998 		struct sockbuf *r, *s;
1999 		struct timeval tv;
2000 
2001 		if (bbr->rc_inp->inp_socket) {
2002 			r = &bbr->rc_inp->inp_socket->so_rcv;
2003 			s = &bbr->rc_inp->inp_socket->so_snd;
2004 		} else {
2005 			r = s = NULL;
2006 		}
2007 		bbr_fill_in_logging_data(bbr, &log.u_bbr, tcp_get_usecs(&tv));
2008 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2009 		    r, s,
2010 		    TCP_LOG_FLOWEND, 0,
2011 		    0, &log, false, &tv);
2012 	}
2013 }
2014 
2015 static void
2016 bbr_log_pkt_epoch(struct tcp_bbr *bbr, uint32_t cts, uint32_t line,
2017     uint32_t lost, uint32_t del)
2018 {
2019 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2020 		union tcp_log_stackspecific log;
2021 
2022 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2023 		log.u_bbr.flex1 = lost;
2024 		log.u_bbr.flex2 = del;
2025 		log.u_bbr.flex3 = bbr->r_ctl.rc_bbr_lastbtlbw;
2026 		log.u_bbr.flex4 = bbr->r_ctl.rc_pkt_epoch_rtt;
2027 		log.u_bbr.flex5 = bbr->r_ctl.rc_bbr_last_startup_epoch;
2028 		log.u_bbr.flex6 = bbr->r_ctl.rc_lost_at_startup;
2029 		log.u_bbr.flex7 = line;
2030 		log.u_bbr.flex8 = 0;
2031 		log.u_bbr.inflight = bbr->r_ctl.r_measurement_count;
2032 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2033 		    &bbr->rc_inp->inp_socket->so_rcv,
2034 		    &bbr->rc_inp->inp_socket->so_snd,
2035 		    BBR_LOG_PKT_EPOCH, 0,
2036 		    0, &log, false, &bbr->rc_tv);
2037 	}
2038 }
2039 
2040 static void
2041 bbr_log_time_epoch(struct tcp_bbr *bbr, uint32_t cts, uint32_t line, uint32_t epoch_time)
2042 {
2043 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2044 		union tcp_log_stackspecific log;
2045 
2046 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2047 		log.u_bbr.flex1 = bbr->r_ctl.rc_lost;
2048 		log.u_bbr.flex2 = bbr->rc_inp->inp_socket->so_snd.sb_lowat;
2049 		log.u_bbr.flex3 = bbr->rc_inp->inp_socket->so_snd.sb_hiwat;
2050 		log.u_bbr.flex7 = line;
2051 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2052 		    &bbr->rc_inp->inp_socket->so_rcv,
2053 		    &bbr->rc_inp->inp_socket->so_snd,
2054 		    BBR_LOG_TIME_EPOCH, 0,
2055 		    0, &log, false, &bbr->rc_tv);
2056 	}
2057 }
2058 
2059 static void
2060 bbr_log_set_of_state_target(struct tcp_bbr *bbr, uint32_t new_tar, int line, int meth)
2061 {
2062 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2063 		union tcp_log_stackspecific log;
2064 
2065 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2066 		log.u_bbr.flex1 = bbr->r_ctl.rc_target_at_state;
2067 		log.u_bbr.flex2 = new_tar;
2068 		log.u_bbr.flex3 = line;
2069 		log.u_bbr.flex4 = bbr->r_ctl.rc_pace_max_segs;
2070 		log.u_bbr.flex5 = bbr_quanta;
2071 		log.u_bbr.flex6 = bbr->r_ctl.rc_pace_min_segs;
2072 		log.u_bbr.flex7 = bbr->rc_last_options;
2073 		log.u_bbr.flex8 = meth;
2074 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2075 		    &bbr->rc_inp->inp_socket->so_rcv,
2076 		    &bbr->rc_inp->inp_socket->so_snd,
2077 		    BBR_LOG_STATE_TARGET, 0,
2078 		    0, &log, false, &bbr->rc_tv);
2079 	}
2080 
2081 }
2082 
2083 static void
2084 bbr_log_type_statechange(struct tcp_bbr *bbr, uint32_t cts, int32_t line)
2085 {
2086 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2087 		union tcp_log_stackspecific log;
2088 
2089 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2090 		log.u_bbr.flex1 = line;
2091 		log.u_bbr.flex2 = bbr->r_ctl.rc_rtt_shrinks;
2092 		log.u_bbr.flex3 = bbr->r_ctl.rc_probertt_int;
2093 		if (bbr_state_is_pkt_epoch)
2094 			log.u_bbr.flex4 = bbr_get_rtt(bbr, BBR_RTT_PKTRTT);
2095 		else
2096 			log.u_bbr.flex4 = bbr_get_rtt(bbr, BBR_RTT_PROP);
2097 		log.u_bbr.flex5 = bbr->r_ctl.rc_bbr_last_startup_epoch;
2098 		log.u_bbr.flex6 = bbr->r_ctl.rc_lost_at_startup;
2099 		log.u_bbr.flex7 = (bbr->r_ctl.rc_target_at_state/1000);
2100 		log.u_bbr.lt_epoch = bbr->r_ctl.rc_level_state_extra;
2101 		log.u_bbr.pkts_out = bbr->r_ctl.rc_target_at_state;
2102 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2103 		    &bbr->rc_inp->inp_socket->so_rcv,
2104 		    &bbr->rc_inp->inp_socket->so_snd,
2105 		    BBR_LOG_STATE, 0,
2106 		    0, &log, false, &bbr->rc_tv);
2107 	}
2108 }
2109 
2110 static void
2111 bbr_log_rtt_shrinks(struct tcp_bbr *bbr, uint32_t cts, uint32_t applied,
2112 		    uint32_t rtt, uint32_t line, uint8_t reas, uint16_t cond)
2113 {
2114 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2115 		union tcp_log_stackspecific log;
2116 
2117 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2118 		log.u_bbr.flex1 = line;
2119 		log.u_bbr.flex2 = bbr->r_ctl.rc_rtt_shrinks;
2120 		log.u_bbr.flex3 = bbr->r_ctl.last_in_probertt;
2121 		log.u_bbr.flex4 = applied;
2122 		log.u_bbr.flex5 = rtt;
2123 		log.u_bbr.flex6 = bbr->r_ctl.rc_target_at_state;
2124 		log.u_bbr.flex7 = cond;
2125 		log.u_bbr.flex8 = reas;
2126 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2127 		    &bbr->rc_inp->inp_socket->so_rcv,
2128 		    &bbr->rc_inp->inp_socket->so_snd,
2129 		    BBR_LOG_RTT_SHRINKS, 0,
2130 		    0, &log, false, &bbr->rc_tv);
2131 	}
2132 }
2133 
2134 static void
2135 bbr_log_type_exit_rec(struct tcp_bbr *bbr)
2136 {
2137 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2138 		union tcp_log_stackspecific log;
2139 
2140 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2141 		log.u_bbr.flex1 = bbr->r_ctl.rc_recovery_start;
2142 		log.u_bbr.flex2 = bbr->r_ctl.rc_cwnd_on_ent;
2143 		log.u_bbr.flex5 = bbr->r_ctl.rc_target_at_state;
2144 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2145 		    &bbr->rc_inp->inp_socket->so_rcv,
2146 		    &bbr->rc_inp->inp_socket->so_snd,
2147 		    BBR_LOG_EXITREC, 0,
2148 		    0, &log, false, &bbr->rc_tv);
2149 	}
2150 }
2151 
2152 static void
2153 bbr_log_type_cwndupd(struct tcp_bbr *bbr, uint32_t bytes_this_ack, uint32_t chg,
2154     uint32_t prev_acked, int32_t meth, uint32_t target, uint32_t th_ack, int32_t line)
2155 {
2156 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2157 		union tcp_log_stackspecific log;
2158 
2159 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2160 		log.u_bbr.flex1 = line;
2161 		log.u_bbr.flex2 = prev_acked;
2162 		log.u_bbr.flex3 = bytes_this_ack;
2163 		log.u_bbr.flex4 = chg;
2164 		log.u_bbr.flex5 = th_ack;
2165 		log.u_bbr.flex6 = target;
2166 		log.u_bbr.flex8 = meth;
2167 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2168 		    &bbr->rc_inp->inp_socket->so_rcv,
2169 		    &bbr->rc_inp->inp_socket->so_snd,
2170 		    BBR_LOG_CWND, 0,
2171 		    0, &log, false, &bbr->rc_tv);
2172 	}
2173 }
2174 
2175 static void
2176 bbr_log_rtt_sample(struct tcp_bbr *bbr, uint32_t rtt, uint32_t tsin)
2177 {
2178 	/*
2179 	 * Log the rtt sample we are applying to the srtt algorithm in
2180 	 * useconds.
2181 	 */
2182 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2183 		union tcp_log_stackspecific log;
2184 
2185 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2186 		log.u_bbr.flex1 = rtt;
2187 		log.u_bbr.flex2 = bbr->r_ctl.rc_bbr_state_time;
2188 		log.u_bbr.flex3 = bbr->r_ctl.rc_ack_hdwr_delay;
2189 		log.u_bbr.flex4 = bbr->rc_tp->ts_offset;
2190 		log.u_bbr.flex5 = bbr->r_ctl.rc_target_at_state;
2191 		log.u_bbr.pkts_out = tcp_tv_to_mssectick(&bbr->rc_tv);
2192 		log.u_bbr.flex6 = tsin;
2193 		log.u_bbr.flex7 = 0;
2194 		log.u_bbr.flex8 = bbr->rc_ack_was_delayed;
2195 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2196 		    &bbr->rc_inp->inp_socket->so_rcv,
2197 		    &bbr->rc_inp->inp_socket->so_snd,
2198 		    TCP_LOG_RTT, 0,
2199 		    0, &log, false, &bbr->rc_tv);
2200 	}
2201 }
2202 
2203 static void
2204 bbr_log_type_pesist(struct tcp_bbr *bbr, uint32_t cts, uint32_t time_in, int32_t line, uint8_t enter_exit)
2205 {
2206 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2207 		union tcp_log_stackspecific log;
2208 
2209 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2210 		log.u_bbr.flex1 = time_in;
2211 		log.u_bbr.flex2 = line;
2212 		log.u_bbr.flex8 = enter_exit;
2213 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2214 		    &bbr->rc_inp->inp_socket->so_rcv,
2215 		    &bbr->rc_inp->inp_socket->so_snd,
2216 		    BBR_LOG_PERSIST, 0,
2217 		    0, &log, false, &bbr->rc_tv);
2218 	}
2219 }
2220 static void
2221 bbr_log_ack_clear(struct tcp_bbr *bbr, uint32_t cts)
2222 {
2223 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2224 		union tcp_log_stackspecific log;
2225 
2226 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2227 		log.u_bbr.flex1 = bbr->rc_tp->ts_recent_age;
2228 		log.u_bbr.flex2 = bbr->r_ctl.rc_rtt_shrinks;
2229 		log.u_bbr.flex3 = bbr->r_ctl.rc_probertt_int;
2230 		log.u_bbr.flex4 = bbr->r_ctl.rc_went_idle_time;
2231 		log.u_bbr.flex5 = bbr->r_ctl.rc_target_at_state;
2232 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2233 		    &bbr->rc_inp->inp_socket->so_rcv,
2234 		    &bbr->rc_inp->inp_socket->so_snd,
2235 		    BBR_LOG_ACKCLEAR, 0,
2236 		    0, &log, false, &bbr->rc_tv);
2237 	}
2238 }
2239 
2240 static void
2241 bbr_log_ack_event(struct tcp_bbr *bbr, struct tcphdr *th, struct tcpopt *to, uint32_t tlen,
2242 		  uint16_t nsegs, uint32_t cts, int32_t nxt_pkt, struct mbuf *m)
2243 {
2244 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2245 		union tcp_log_stackspecific log;
2246 		struct timeval tv;
2247 
2248 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2249 		log.u_bbr.flex1 = nsegs;
2250 		log.u_bbr.flex2 = bbr->r_ctl.rc_lost_bytes;
2251 		if (m) {
2252 			struct timespec ts;
2253 
2254 			log.u_bbr.flex3 = m->m_flags;
2255 			if (m->m_flags & M_TSTMP) {
2256 				mbuf_tstmp2timespec(m, &ts);
2257 				tv.tv_sec = ts.tv_sec;
2258 				tv.tv_usec = ts.tv_nsec / 1000;
2259 				log.u_bbr.lt_epoch = tcp_tv_to_usectick(&tv);
2260 			} else {
2261 				log.u_bbr.lt_epoch = 0;
2262 			}
2263 			if (m->m_flags & M_TSTMP_LRO) {
2264 				tv.tv_sec = m->m_pkthdr.rcv_tstmp / 1000000000;
2265 				tv.tv_usec = (m->m_pkthdr.rcv_tstmp % 1000000000) / 1000;
2266 				log.u_bbr.flex5 = tcp_tv_to_usectick(&tv);
2267 			} else {
2268 				/* No arrival timestamp */
2269 				log.u_bbr.flex5 = 0;
2270 			}
2271 
2272 			log.u_bbr.pkts_out = tcp_get_usecs(&tv);
2273 		} else {
2274 			log.u_bbr.flex3 = 0;
2275 			log.u_bbr.flex5 = 0;
2276 			log.u_bbr.flex6 = 0;
2277 			log.u_bbr.pkts_out = 0;
2278 		}
2279 		log.u_bbr.flex4 = bbr->r_ctl.rc_target_at_state;
2280 		log.u_bbr.flex7 = bbr->r_wanted_output;
2281 		log.u_bbr.flex8 = bbr->rc_in_persist;
2282 		TCP_LOG_EVENTP(bbr->rc_tp, th,
2283 		    &bbr->rc_inp->inp_socket->so_rcv,
2284 		    &bbr->rc_inp->inp_socket->so_snd,
2285 		    TCP_LOG_IN, 0,
2286 		    tlen, &log, true, &bbr->rc_tv);
2287 	}
2288 }
2289 
2290 static void
2291 bbr_log_doseg_done(struct tcp_bbr *bbr, uint32_t cts, int32_t nxt_pkt, int32_t did_out)
2292 {
2293 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2294 		union tcp_log_stackspecific log;
2295 
2296 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2297 		log.u_bbr.flex1 = did_out;
2298 		log.u_bbr.flex2 = nxt_pkt;
2299 		log.u_bbr.flex3 = bbr->r_ctl.rc_last_delay_val;
2300 		log.u_bbr.flex4 = bbr->r_ctl.rc_hpts_flags;
2301 		log.u_bbr.flex5 = bbr->r_ctl.rc_timer_exp;
2302 		log.u_bbr.flex6 = bbr->r_ctl.rc_lost_bytes;
2303 		log.u_bbr.flex7 = bbr->r_wanted_output;
2304 		log.u_bbr.flex8 = bbr->rc_in_persist;
2305 		log.u_bbr.pkts_out = bbr->r_ctl.highest_hdwr_delay;
2306 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2307 		    &bbr->rc_inp->inp_socket->so_rcv,
2308 		    &bbr->rc_inp->inp_socket->so_snd,
2309 		    BBR_LOG_DOSEG_DONE, 0,
2310 		    0, &log, true, &bbr->rc_tv);
2311 	}
2312 }
2313 
2314 static void
2315 bbr_log_enobuf_jmp(struct tcp_bbr *bbr, uint32_t len, uint32_t cts,
2316     int32_t line, uint32_t o_len, uint32_t segcnt, uint32_t segsiz)
2317 {
2318 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2319 		union tcp_log_stackspecific log;
2320 
2321 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2322 		log.u_bbr.flex1 = line;
2323 		log.u_bbr.flex2 = o_len;
2324 		log.u_bbr.flex3 = segcnt;
2325 		log.u_bbr.flex4 = segsiz;
2326 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2327 		    &bbr->rc_inp->inp_socket->so_rcv,
2328 		    &bbr->rc_inp->inp_socket->so_snd,
2329 		    BBR_LOG_ENOBUF_JMP, ENOBUFS,
2330 		    len, &log, true, &bbr->rc_tv);
2331 	}
2332 }
2333 
2334 static void
2335 bbr_log_to_processing(struct tcp_bbr *bbr, uint32_t cts, int32_t ret, int32_t timers, uint8_t hpts_calling)
2336 {
2337 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2338 		union tcp_log_stackspecific log;
2339 
2340 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2341 		log.u_bbr.flex1 = timers;
2342 		log.u_bbr.flex2 = ret;
2343 		log.u_bbr.flex3 = bbr->r_ctl.rc_timer_exp;
2344 		log.u_bbr.flex4 = bbr->r_ctl.rc_hpts_flags;
2345 		log.u_bbr.flex5 = cts;
2346 		log.u_bbr.flex6 = bbr->r_ctl.rc_target_at_state;
2347 		log.u_bbr.flex8 = hpts_calling;
2348 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2349 		    &bbr->rc_inp->inp_socket->so_rcv,
2350 		    &bbr->rc_inp->inp_socket->so_snd,
2351 		    BBR_LOG_TO_PROCESS, 0,
2352 		    0, &log, false, &bbr->rc_tv);
2353 	}
2354 }
2355 
2356 static void
2357 bbr_log_to_event(struct tcp_bbr *bbr, uint32_t cts, int32_t to_num)
2358 {
2359 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2360 		union tcp_log_stackspecific log;
2361 		uint64_t ar;
2362 
2363 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2364 		log.u_bbr.flex1 = bbr->bbr_timer_src;
2365 		log.u_bbr.flex2 = 0;
2366 		log.u_bbr.flex3 = bbr->r_ctl.rc_hpts_flags;
2367 		ar = (uint64_t)(bbr->r_ctl.rc_resend);
2368 		ar >>= 32;
2369 		ar &= 0x00000000ffffffff;
2370 		log.u_bbr.flex4 = (uint32_t)ar;
2371 		ar = (uint64_t)bbr->r_ctl.rc_resend;
2372 		ar &= 0x00000000ffffffff;
2373 		log.u_bbr.flex5 = (uint32_t)ar;
2374 		log.u_bbr.flex6 = TICKS_2_USEC(bbr->rc_tp->t_rxtcur);
2375 		log.u_bbr.flex8 = to_num;
2376 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2377 		    &bbr->rc_inp->inp_socket->so_rcv,
2378 		    &bbr->rc_inp->inp_socket->so_snd,
2379 		    BBR_LOG_RTO, 0,
2380 		    0, &log, false, &bbr->rc_tv);
2381 	}
2382 }
2383 
2384 static void
2385 bbr_log_startup_event(struct tcp_bbr *bbr, uint32_t cts, uint32_t flex1, uint32_t flex2, uint32_t flex3, uint8_t reason)
2386 {
2387 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2388 		union tcp_log_stackspecific log;
2389 
2390 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2391 		log.u_bbr.flex1 = flex1;
2392 		log.u_bbr.flex2 = flex2;
2393 		log.u_bbr.flex3 = flex3;
2394 		log.u_bbr.flex4 = 0;
2395 		log.u_bbr.flex5 = bbr->r_ctl.rc_target_at_state;
2396 		log.u_bbr.flex6 = bbr->r_ctl.rc_lost_at_startup;
2397 		log.u_bbr.flex8 = reason;
2398 		log.u_bbr.cur_del_rate = bbr->r_ctl.rc_bbr_lastbtlbw;
2399 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2400 		    &bbr->rc_inp->inp_socket->so_rcv,
2401 		    &bbr->rc_inp->inp_socket->so_snd,
2402 		    BBR_LOG_REDUCE, 0,
2403 		    0, &log, false, &bbr->rc_tv);
2404 	}
2405 }
2406 
2407 static void
2408 bbr_log_hpts_diag(struct tcp_bbr *bbr, uint32_t cts, struct hpts_diag *diag)
2409 {
2410 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2411 		union tcp_log_stackspecific log;
2412 
2413 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2414 		log.u_bbr.flex1 = diag->p_nxt_slot;
2415 		log.u_bbr.flex2 = diag->p_cur_slot;
2416 		log.u_bbr.flex3 = diag->slot_req;
2417 		log.u_bbr.flex4 = diag->inp_hptsslot;
2418 		log.u_bbr.flex5 = diag->slot_remaining;
2419 		log.u_bbr.flex6 = diag->need_new_to;
2420 		log.u_bbr.flex7 = diag->p_hpts_active;
2421 		log.u_bbr.flex8 = diag->p_on_min_sleep;
2422 		/* Hijack other fields as needed  */
2423 		log.u_bbr.epoch = diag->have_slept;
2424 		log.u_bbr.lt_epoch = diag->yet_to_sleep;
2425 		log.u_bbr.pkts_out = diag->co_ret;
2426 		log.u_bbr.applimited = diag->hpts_sleep_time;
2427 		log.u_bbr.delivered = diag->p_prev_slot;
2428 		log.u_bbr.inflight = diag->p_runningtick;
2429 		log.u_bbr.bw_inuse = diag->wheel_tick;
2430 		log.u_bbr.rttProp = diag->wheel_cts;
2431 		log.u_bbr.delRate = diag->maxticks;
2432 		log.u_bbr.cur_del_rate = diag->p_curtick;
2433 		log.u_bbr.cur_del_rate <<= 32;
2434 		log.u_bbr.cur_del_rate |= diag->p_lasttick;
2435 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2436 		    &bbr->rc_inp->inp_socket->so_rcv,
2437 		    &bbr->rc_inp->inp_socket->so_snd,
2438 		    BBR_LOG_HPTSDIAG, 0,
2439 		    0, &log, false, &bbr->rc_tv);
2440 	}
2441 }
2442 
2443 static void
2444 bbr_log_timer_var(struct tcp_bbr *bbr, int mode, uint32_t cts, uint32_t time_since_sent, uint32_t srtt,
2445     uint32_t thresh, uint32_t to)
2446 {
2447 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2448 		union tcp_log_stackspecific log;
2449 
2450 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2451 		log.u_bbr.flex1 = bbr->rc_tp->t_rttvar;
2452 		log.u_bbr.flex2 = time_since_sent;
2453 		log.u_bbr.flex3 = srtt;
2454 		log.u_bbr.flex4 = thresh;
2455 		log.u_bbr.flex5 = to;
2456 		log.u_bbr.flex6 = bbr->rc_tp->t_srtt;
2457 		log.u_bbr.flex8 = mode;
2458 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2459 		    &bbr->rc_inp->inp_socket->so_rcv,
2460 		    &bbr->rc_inp->inp_socket->so_snd,
2461 		    BBR_LOG_TIMERPREP, 0,
2462 		    0, &log, false, &bbr->rc_tv);
2463 	}
2464 }
2465 
2466 static void
2467 bbr_log_pacing_delay_calc(struct tcp_bbr *bbr, uint16_t gain, uint32_t len,
2468     uint32_t cts, uint32_t usecs, uint64_t bw, uint32_t override, int mod)
2469 {
2470 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2471 		union tcp_log_stackspecific log;
2472 
2473 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2474 		log.u_bbr.flex1 = usecs;
2475 		log.u_bbr.flex2 = len;
2476 		log.u_bbr.flex3 = (uint32_t)((bw >> 32) & 0x00000000ffffffff);
2477 		log.u_bbr.flex4 = (uint32_t)(bw & 0x00000000ffffffff);
2478 		if (override)
2479 			log.u_bbr.flex5 = (1 << 2);
2480 		else
2481 			log.u_bbr.flex5 = 0;
2482 		log.u_bbr.flex6 = override;
2483 		log.u_bbr.flex7 = gain;
2484 		log.u_bbr.flex8 = mod;
2485 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2486 		    &bbr->rc_inp->inp_socket->so_rcv,
2487 		    &bbr->rc_inp->inp_socket->so_snd,
2488 		    BBR_LOG_HPTSI_CALC, 0,
2489 		    len, &log, false, &bbr->rc_tv);
2490 	}
2491 }
2492 
2493 static void
2494 bbr_log_to_start(struct tcp_bbr *bbr, uint32_t cts, uint32_t to, int32_t slot, uint8_t which)
2495 {
2496 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2497 		union tcp_log_stackspecific log;
2498 
2499 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2500 
2501 		log.u_bbr.flex1 = bbr->bbr_timer_src;
2502 		log.u_bbr.flex2 = to;
2503 		log.u_bbr.flex3 = bbr->r_ctl.rc_hpts_flags;
2504 		log.u_bbr.flex4 = slot;
2505 		log.u_bbr.flex5 = bbr->rc_inp->inp_hptsslot;
2506 		log.u_bbr.flex6 = TICKS_2_USEC(bbr->rc_tp->t_rxtcur);
2507 		log.u_bbr.pkts_out = bbr->rc_inp->inp_flags2;
2508 		log.u_bbr.flex8 = which;
2509 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2510 		    &bbr->rc_inp->inp_socket->so_rcv,
2511 		    &bbr->rc_inp->inp_socket->so_snd,
2512 		    BBR_LOG_TIMERSTAR, 0,
2513 		    0, &log, false, &bbr->rc_tv);
2514 	}
2515 }
2516 
2517 static void
2518 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)
2519 {
2520 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2521 		union tcp_log_stackspecific log;
2522 
2523 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2524 		log.u_bbr.flex1 = thresh;
2525 		log.u_bbr.flex2 = lro;
2526 		log.u_bbr.flex3 = bbr->r_ctl.rc_reorder_ts;
2527 		log.u_bbr.flex4 = rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)];
2528 		log.u_bbr.flex5 = TICKS_2_USEC(bbr->rc_tp->t_rxtcur);
2529 		log.u_bbr.flex6 = srtt;
2530 		log.u_bbr.flex7 = bbr->r_ctl.rc_reorder_shift;
2531 		log.u_bbr.flex8 = frm;
2532 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2533 		    &bbr->rc_inp->inp_socket->so_rcv,
2534 		    &bbr->rc_inp->inp_socket->so_snd,
2535 		    BBR_LOG_THRESH_CALC, 0,
2536 		    0, &log, false, &bbr->rc_tv);
2537 	}
2538 }
2539 
2540 static void
2541 bbr_log_to_cancel(struct tcp_bbr *bbr, int32_t line, uint32_t cts, uint8_t hpts_removed)
2542 {
2543 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2544 		union tcp_log_stackspecific log;
2545 
2546 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2547 		log.u_bbr.flex1 = line;
2548 		log.u_bbr.flex2 = bbr->bbr_timer_src;
2549 		log.u_bbr.flex3 = bbr->r_ctl.rc_hpts_flags;
2550 		log.u_bbr.flex4 = bbr->rc_in_persist;
2551 		log.u_bbr.flex5 = bbr->r_ctl.rc_target_at_state;
2552 		log.u_bbr.flex6 = TICKS_2_USEC(bbr->rc_tp->t_rxtcur);
2553 		log.u_bbr.flex8 = hpts_removed;
2554 		log.u_bbr.pkts_out = bbr->rc_pacer_started;
2555 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2556 		    &bbr->rc_inp->inp_socket->so_rcv,
2557 		    &bbr->rc_inp->inp_socket->so_snd,
2558 		    BBR_LOG_TIMERCANC, 0,
2559 		    0, &log, false, &bbr->rc_tv);
2560 	}
2561 }
2562 
2563 static void
2564 bbr_log_tstmp_validation(struct tcp_bbr *bbr, uint64_t peer_delta, uint64_t delta)
2565 {
2566 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2567 		union tcp_log_stackspecific log;
2568 
2569 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2570 		log.u_bbr.flex1 = bbr->r_ctl.bbr_peer_tsratio;
2571 		log.u_bbr.flex2 = (peer_delta >> 32);
2572 		log.u_bbr.flex3 = (peer_delta & 0x00000000ffffffff);
2573 		log.u_bbr.flex4 = (delta >> 32);
2574 		log.u_bbr.flex5 = (delta & 0x00000000ffffffff);
2575 		log.u_bbr.flex7 = bbr->rc_ts_clock_set;
2576 		log.u_bbr.flex8 = bbr->rc_ts_cant_be_used;
2577 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2578 		    &bbr->rc_inp->inp_socket->so_rcv,
2579 		    &bbr->rc_inp->inp_socket->so_snd,
2580 		    BBR_LOG_TSTMP_VAL, 0,
2581 		    0, &log, false, &bbr->rc_tv);
2582 	}
2583 }
2584 
2585 static void
2586 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)
2587 {
2588 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2589 		union tcp_log_stackspecific log;
2590 
2591 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2592 		log.u_bbr.flex1 = tsosz;
2593 		log.u_bbr.flex2 = tls;
2594 		log.u_bbr.flex3 = tcp_min_hptsi_time;
2595 		log.u_bbr.flex4 = bbr->r_ctl.bbr_hptsi_bytes_min;
2596 		log.u_bbr.flex5 = old_val;
2597 		log.u_bbr.flex6 = maxseg;
2598 		log.u_bbr.flex7 = bbr->rc_no_pacing;
2599 		log.u_bbr.flex7 <<= 1;
2600 		log.u_bbr.flex7 |= bbr->rc_past_init_win;
2601 		if (hdwr)
2602 			log.u_bbr.flex8 = 0x80 | bbr->rc_use_google;
2603 		else
2604 			log.u_bbr.flex8 = bbr->rc_use_google;
2605 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2606 		    &bbr->rc_inp->inp_socket->so_rcv,
2607 		    &bbr->rc_inp->inp_socket->so_snd,
2608 		    BBR_LOG_BBRTSO, 0,
2609 		    0, &log, false, &bbr->rc_tv);
2610 	}
2611 }
2612 
2613 static void
2614 bbr_log_type_rsmclear(struct tcp_bbr *bbr, uint32_t cts, struct bbr_sendmap *rsm,
2615 		      uint32_t flags, uint32_t line)
2616 {
2617 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2618 		union tcp_log_stackspecific log;
2619 
2620 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2621 		log.u_bbr.flex1 = line;
2622 		log.u_bbr.flex2 = rsm->r_start;
2623 		log.u_bbr.flex3 = rsm->r_end;
2624 		log.u_bbr.flex4 = rsm->r_delivered;
2625 		log.u_bbr.flex5 = rsm->r_rtr_cnt;
2626 		log.u_bbr.flex6 = rsm->r_dupack;
2627 		log.u_bbr.flex7 = rsm->r_tim_lastsent[0];
2628 		log.u_bbr.flex8 = rsm->r_flags;
2629 		/* Hijack the pkts_out fids */
2630 		log.u_bbr.applimited = flags;
2631 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2632 		    &bbr->rc_inp->inp_socket->so_rcv,
2633 		    &bbr->rc_inp->inp_socket->so_snd,
2634 		    BBR_RSM_CLEARED, 0,
2635 		    0, &log, false, &bbr->rc_tv);
2636 	}
2637 }
2638 
2639 static void
2640 bbr_log_type_bbrupd(struct tcp_bbr *bbr, uint8_t flex8, uint32_t cts,
2641     uint32_t flex3, uint32_t flex2, uint32_t flex5,
2642     uint32_t flex6, uint32_t pkts_out, int flex7,
2643     uint32_t flex4, uint32_t flex1)
2644 {
2645 
2646 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2647 		union tcp_log_stackspecific log;
2648 
2649 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2650 		log.u_bbr.flex1 = flex1;
2651 		log.u_bbr.flex2 = flex2;
2652 		log.u_bbr.flex3 = flex3;
2653 		log.u_bbr.flex4 = flex4;
2654 		log.u_bbr.flex5 = flex5;
2655 		log.u_bbr.flex6 = flex6;
2656 		log.u_bbr.flex7 = flex7;
2657 		/* Hijack the pkts_out fids */
2658 		log.u_bbr.pkts_out = pkts_out;
2659 		log.u_bbr.flex8 = flex8;
2660 		if (bbr->rc_ack_was_delayed)
2661 			log.u_bbr.epoch = bbr->r_ctl.rc_ack_hdwr_delay;
2662 		else
2663 			log.u_bbr.epoch = 0;
2664 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2665 		    &bbr->rc_inp->inp_socket->so_rcv,
2666 		    &bbr->rc_inp->inp_socket->so_snd,
2667 		    BBR_LOG_BBRUPD, 0,
2668 		    flex2, &log, false, &bbr->rc_tv);
2669 	}
2670 }
2671 
2672 static void
2673 bbr_log_type_ltbw(struct tcp_bbr *bbr, uint32_t cts, int32_t reason,
2674 	uint32_t newbw, uint32_t obw, uint32_t diff,
2675 	uint32_t tim)
2676 {
2677 	if (/*bbr_verbose_logging && */(bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2678 		union tcp_log_stackspecific log;
2679 
2680 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2681 		log.u_bbr.flex1 = reason;
2682 		log.u_bbr.flex2 = newbw;
2683 		log.u_bbr.flex3 = obw;
2684 		log.u_bbr.flex4 = diff;
2685 		log.u_bbr.flex5 = bbr->r_ctl.rc_lt_lost;
2686 		log.u_bbr.flex6 = bbr->r_ctl.rc_lt_del;
2687 		log.u_bbr.flex7 = bbr->rc_lt_is_sampling;
2688 		log.u_bbr.pkts_out = tim;
2689 		log.u_bbr.bw_inuse = bbr->r_ctl.rc_lt_bw;
2690 		if (bbr->rc_lt_use_bw == 0)
2691 			log.u_bbr.epoch = bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_lt_epoch;
2692 		else
2693 			log.u_bbr.epoch = bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_lt_epoch_use;
2694 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2695 		    &bbr->rc_inp->inp_socket->so_rcv,
2696 		    &bbr->rc_inp->inp_socket->so_snd,
2697 		    BBR_LOG_BWSAMP, 0,
2698 		    0, &log, false, &bbr->rc_tv);
2699 	}
2700 }
2701 
2702 static inline void
2703 bbr_log_progress_event(struct tcp_bbr *bbr, struct tcpcb *tp, uint32_t tick, int event, int line)
2704 {
2705 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2706 		union tcp_log_stackspecific log;
2707 
2708 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2709 		log.u_bbr.flex1 = line;
2710 		log.u_bbr.flex2 = tick;
2711 		log.u_bbr.flex3 = tp->t_maxunacktime;
2712 		log.u_bbr.flex4 = tp->t_acktime;
2713 		log.u_bbr.flex8 = event;
2714 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2715 		    &bbr->rc_inp->inp_socket->so_rcv,
2716 		    &bbr->rc_inp->inp_socket->so_snd,
2717 		    BBR_LOG_PROGRESS, 0,
2718 		    0, &log, false, &bbr->rc_tv);
2719 	}
2720 }
2721 
2722 static void
2723 bbr_type_log_hdwr_pacing(struct tcp_bbr *bbr, const struct ifnet *ifp,
2724 			 uint64_t rate, uint64_t hw_rate, int line, uint32_t cts,
2725 			 int error)
2726 {
2727 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2728 		union tcp_log_stackspecific log;
2729 
2730 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2731 		log.u_bbr.flex1 = ((hw_rate >> 32) & 0x00000000ffffffff);
2732 		log.u_bbr.flex2 = (hw_rate & 0x00000000ffffffff);
2733 		log.u_bbr.flex3 = (((uint64_t)ifp  >> 32) & 0x00000000ffffffff);
2734 		log.u_bbr.flex4 = ((uint64_t)ifp & 0x00000000ffffffff);
2735 		log.u_bbr.bw_inuse = rate;
2736 		log.u_bbr.flex5 = line;
2737 		log.u_bbr.flex6 = error;
2738 		log.u_bbr.flex8 = bbr->skip_gain;
2739 		log.u_bbr.flex8 <<= 1;
2740 		log.u_bbr.flex8 |= bbr->gain_is_limited;
2741 		log.u_bbr.flex8 <<= 1;
2742 		log.u_bbr.flex8 |= bbr->bbr_hdrw_pacing;
2743 		log.u_bbr.pkts_out = bbr->rc_tp->t_maxseg;
2744 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2745 		    &bbr->rc_inp->inp_socket->so_rcv,
2746 		    &bbr->rc_inp->inp_socket->so_snd,
2747 		    BBR_LOG_HDWR_PACE, 0,
2748 		    0, &log, false, &bbr->rc_tv);
2749 	}
2750 }
2751 
2752 static void
2753 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)
2754 {
2755 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2756 		union tcp_log_stackspecific log;
2757 
2758 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2759 		log.u_bbr.flex1 = slot;
2760 		log.u_bbr.flex2 = del_by;
2761 		log.u_bbr.flex3 = prev_delay;
2762 		log.u_bbr.flex4 = line;
2763 		log.u_bbr.flex5 = bbr->r_ctl.rc_last_delay_val;
2764 		log.u_bbr.flex6 = bbr->r_ctl.rc_hptsi_agg_delay;
2765 		log.u_bbr.flex7 = (0x0000ffff & bbr->r_ctl.rc_hpts_flags);
2766 		log.u_bbr.flex8 = bbr->rc_in_persist;
2767 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2768 		    &bbr->rc_inp->inp_socket->so_rcv,
2769 		    &bbr->rc_inp->inp_socket->so_snd,
2770 		    BBR_LOG_BBRSND, 0,
2771 		    len, &log, false, &bbr->rc_tv);
2772 	}
2773 }
2774 
2775 static void
2776 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)
2777 {
2778 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2779 		union tcp_log_stackspecific log;
2780 
2781 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2782 		log.u_bbr.flex1 = bbr->r_ctl.rc_delivered;
2783 		log.u_bbr.flex2 = 0;
2784 		log.u_bbr.flex3 = bbr->r_ctl.rc_lowest_rtt;
2785 		log.u_bbr.flex4 = end;
2786 		log.u_bbr.flex5 = seq;
2787 		log.u_bbr.flex6 = t;
2788 		log.u_bbr.flex7 = match;
2789 		log.u_bbr.flex8 = flags;
2790 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2791 		    &bbr->rc_inp->inp_socket->so_rcv,
2792 		    &bbr->rc_inp->inp_socket->so_snd,
2793 		    BBR_LOG_BBRRTT, 0,
2794 		    0, &log, false, &bbr->rc_tv);
2795 	}
2796 }
2797 
2798 static void
2799 bbr_log_exit_gain(struct tcp_bbr *bbr, uint32_t cts, int32_t entry_method)
2800 {
2801 	if (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF) {
2802 		union tcp_log_stackspecific log;
2803 
2804 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
2805 		log.u_bbr.flex1 = bbr->r_ctl.rc_target_at_state;
2806 		log.u_bbr.flex2 = (bbr->rc_tp->t_maxseg - bbr->rc_last_options);
2807 		log.u_bbr.flex3 = bbr->r_ctl.gain_epoch;
2808 		log.u_bbr.flex4 = bbr->r_ctl.rc_pace_max_segs;
2809 		log.u_bbr.flex5 = bbr->r_ctl.rc_pace_min_segs;
2810 		log.u_bbr.flex6 = bbr->r_ctl.rc_bbr_state_atflight;
2811 		log.u_bbr.flex7 = 0;
2812 		log.u_bbr.flex8 = entry_method;
2813 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2814 		    &bbr->rc_inp->inp_socket->so_rcv,
2815 		    &bbr->rc_inp->inp_socket->so_snd,
2816 		    BBR_LOG_EXIT_GAIN, 0,
2817 		    0, &log, false, &bbr->rc_tv);
2818 	}
2819 }
2820 
2821 static void
2822 bbr_log_settings_change(struct tcp_bbr *bbr, int settings_desired)
2823 {
2824 	if (bbr_verbose_logging && (bbr->rc_tp->t_logstate != TCP_LOG_STATE_OFF)) {
2825 		union tcp_log_stackspecific log;
2826 
2827 		bbr_fill_in_logging_data(bbr, &log.u_bbr, bbr->r_ctl.rc_rcvtime);
2828 		/* R-HU */
2829 		log.u_bbr.flex1 = 0;
2830 		log.u_bbr.flex2 = 0;
2831 		log.u_bbr.flex3 = 0;
2832 		log.u_bbr.flex4 = 0;
2833 		log.u_bbr.flex7 = 0;
2834 		log.u_bbr.flex8 = settings_desired;
2835 
2836 		TCP_LOG_EVENTP(bbr->rc_tp, NULL,
2837 		    &bbr->rc_inp->inp_socket->so_rcv,
2838 		    &bbr->rc_inp->inp_socket->so_snd,
2839 		    BBR_LOG_SETTINGS_CHG, 0,
2840 		    0, &log, false, &bbr->rc_tv);
2841 	}
2842 }
2843 
2844 /*
2845  * Returns the bw from the our filter.
2846  */
2847 static inline uint64_t
2848 bbr_get_full_bw(struct tcp_bbr *bbr)
2849 {
2850 	uint64_t bw;
2851 
2852 	bw = get_filter_value(&bbr->r_ctl.rc_delrate);
2853 
2854 	return (bw);
2855 }
2856 
2857 static inline void
2858 bbr_set_pktepoch(struct tcp_bbr *bbr, uint32_t cts, int32_t line)
2859 {
2860 	uint64_t calclr;
2861 	uint32_t lost, del;
2862 
2863 	if (bbr->r_ctl.rc_lost > bbr->r_ctl.rc_lost_at_pktepoch)
2864 		lost = bbr->r_ctl.rc_lost - bbr->r_ctl.rc_lost_at_pktepoch;
2865 	else
2866 		lost = 0;
2867 	del = bbr->r_ctl.rc_delivered - bbr->r_ctl.rc_pkt_epoch_del;
2868 	if (lost == 0)  {
2869 		calclr = 0;
2870 	} else if (del) {
2871 		calclr = lost;
2872 		calclr *= (uint64_t)1000;
2873 		calclr /= (uint64_t)del;
2874 	} else {
2875 		/* Nothing delivered? 100.0% loss */
2876 		calclr = 1000;
2877 	}
2878 	bbr->r_ctl.rc_pkt_epoch_loss_rate =  (uint32_t)calclr;
2879 	if (IN_RECOVERY(bbr->rc_tp->t_flags))
2880 		bbr->r_ctl.recovery_lr += (uint32_t)calclr;
2881 	bbr->r_ctl.rc_pkt_epoch++;
2882 	if (bbr->rc_no_pacing &&
2883 	    (bbr->r_ctl.rc_pkt_epoch >= bbr->no_pacing_until)) {
2884 		bbr->rc_no_pacing = 0;
2885 		tcp_bbr_tso_size_check(bbr, cts);
2886 	}
2887 	bbr->r_ctl.rc_pkt_epoch_rtt = bbr_calc_time(cts, bbr->r_ctl.rc_pkt_epoch_time);
2888 	bbr->r_ctl.rc_pkt_epoch_time = cts;
2889 	/* What was our loss rate */
2890 	bbr_log_pkt_epoch(bbr, cts, line, lost, del);
2891 	bbr->r_ctl.rc_pkt_epoch_del = bbr->r_ctl.rc_delivered;
2892 	bbr->r_ctl.rc_lost_at_pktepoch = bbr->r_ctl.rc_lost;
2893 }
2894 
2895 static inline void
2896 bbr_set_epoch(struct tcp_bbr *bbr, uint32_t cts, int32_t line)
2897 {
2898 	uint32_t epoch_time;
2899 
2900 	/* Tick the RTT clock */
2901 	bbr->r_ctl.rc_rtt_epoch++;
2902 	epoch_time = cts - bbr->r_ctl.rc_rcv_epoch_start;
2903 	bbr_log_time_epoch(bbr, cts, line, epoch_time);
2904 	bbr->r_ctl.rc_rcv_epoch_start = cts;
2905 }
2906 
2907 static inline void
2908 bbr_isit_a_pkt_epoch(struct tcp_bbr *bbr, uint32_t cts, struct bbr_sendmap *rsm, int32_t line, int32_t cum_acked)
2909 {
2910 	if (SEQ_GEQ(rsm->r_delivered, bbr->r_ctl.rc_pkt_epoch_del)) {
2911 		bbr->rc_is_pkt_epoch_now = 1;
2912 	}
2913 }
2914 
2915 /*
2916  * Returns the bw from either the b/w filter
2917  * or from the lt_bw (if the connection is being
2918  * policed).
2919  */
2920 static inline uint64_t
2921 __bbr_get_bw(struct tcp_bbr *bbr)
2922 {
2923 	uint64_t bw, min_bw;
2924 	uint64_t rtt;
2925 	int gm_measure_cnt = 1;
2926 
2927 	/*
2928 	 * For startup we make, like google, a
2929 	 * minimum b/w. This is generated from the
2930 	 * IW and the rttProp. We do fall back to srtt
2931 	 * if for some reason (initial handshake) we don't
2932 	 * have a rttProp. We, in the worst case, fall back
2933 	 * to the configured min_bw (rc_initial_hptsi_bw).
2934 	 */
2935 	if (bbr->rc_bbr_state == BBR_STATE_STARTUP) {
2936 		/* Attempt first to use rttProp */
2937 		rtt = (uint64_t)get_filter_value_small(&bbr->r_ctl.rc_rttprop);
2938 		if (rtt && (rtt < 0xffffffff)) {
2939 measure:
2940 			min_bw = (uint64_t)(bbr_initial_cwnd(bbr, bbr->rc_tp)) *
2941 				((uint64_t)1000000);
2942 			min_bw /= rtt;
2943 			if (min_bw < bbr->r_ctl.rc_initial_hptsi_bw) {
2944 				min_bw = bbr->r_ctl.rc_initial_hptsi_bw;
2945 			}
2946 
2947 		} else if (bbr->rc_tp->t_srtt != 0) {
2948 			/* No rttProp, use srtt? */
2949 			rtt = bbr_get_rtt(bbr, BBR_SRTT);
2950 			goto measure;
2951 		} else {
2952 			min_bw = bbr->r_ctl.rc_initial_hptsi_bw;
2953 		}
2954 	} else
2955 		min_bw = 0;
2956 
2957 	if ((bbr->rc_past_init_win == 0) &&
2958 	    (bbr->r_ctl.rc_delivered > bbr_initial_cwnd(bbr, bbr->rc_tp)))
2959 		bbr->rc_past_init_win = 1;
2960 	if ((bbr->rc_use_google)  && (bbr->r_ctl.r_measurement_count >= 1))
2961 		gm_measure_cnt = 0;
2962 	if (gm_measure_cnt &&
2963 	    ((bbr->r_ctl.r_measurement_count < bbr_min_measurements_req) ||
2964 	     (bbr->rc_past_init_win == 0))) {
2965 		/* For google we use our guess rate until we get 1 measurement */
2966 
2967 use_initial_window:
2968 		rtt = (uint64_t)get_filter_value_small(&bbr->r_ctl.rc_rttprop);
2969 		if (rtt && (rtt < 0xffffffff)) {
2970 			/*
2971 			 * We have an RTT measurment. Use that in
2972 			 * combination with our initial window to calculate
2973 			 * a b/w.
2974 			 */
2975 			bw = (uint64_t)(bbr_initial_cwnd(bbr, bbr->rc_tp)) *
2976 				((uint64_t)1000000);
2977 			bw /= rtt;
2978 			if (bw < bbr->r_ctl.rc_initial_hptsi_bw) {
2979 				bw = bbr->r_ctl.rc_initial_hptsi_bw;
2980 			}
2981 		} else {
2982 			/* Drop back to the 40 and punt to a default */
2983 			bw = bbr->r_ctl.rc_initial_hptsi_bw;
2984 		}
2985 		if (bw < 1)
2986 			/* Probably should panic */
2987 			bw = 1;
2988 		if (bw > min_bw)
2989 			return (bw);
2990 		else
2991 			return (min_bw);
2992 	}
2993 	if (bbr->rc_lt_use_bw)
2994 		bw = bbr->r_ctl.rc_lt_bw;
2995 	else if (bbr->r_recovery_bw && (bbr->rc_use_google == 0))
2996 		bw = bbr->r_ctl.red_bw;
2997 	else
2998 		bw = get_filter_value(&bbr->r_ctl.rc_delrate);
2999 	if (bbr->rc_tp->t_peakrate_thr && (bbr->rc_use_google == 0)) {
3000 		/*
3001 		 * Enforce user set rate limit, keep in mind that
3002 		 * t_peakrate_thr is in B/s already
3003 		 */
3004 		bw = uqmin((uint64_t)bbr->rc_tp->t_peakrate_thr, bw);
3005 	}
3006 	if (bw == 0) {
3007 		/* We should not be at 0, go to the initial window then  */
3008 		goto use_initial_window;
3009 	}
3010 	if (bw < 1)
3011 		/* Probably should panic */
3012 		bw = 1;
3013 	if (bw < min_bw)
3014 		bw = min_bw;
3015 	return (bw);
3016 }
3017 
3018 static inline uint64_t
3019 bbr_get_bw(struct tcp_bbr *bbr)
3020 {
3021 	uint64_t bw;
3022 
3023 	bw = __bbr_get_bw(bbr);
3024 	return (bw);
3025 }
3026 
3027 static inline void
3028 bbr_reset_lt_bw_interval(struct tcp_bbr *bbr, uint32_t cts)
3029 {
3030 	bbr->r_ctl.rc_lt_epoch = bbr->r_ctl.rc_pkt_epoch;
3031 	bbr->r_ctl.rc_lt_time = bbr->r_ctl.rc_del_time;
3032 	bbr->r_ctl.rc_lt_del = bbr->r_ctl.rc_delivered;
3033 	bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
3034 }
3035 
3036 static inline void
3037 bbr_reset_lt_bw_sampling(struct tcp_bbr *bbr, uint32_t cts)
3038 {
3039 	bbr->rc_lt_is_sampling = 0;
3040 	bbr->rc_lt_use_bw = 0;
3041 	bbr->r_ctl.rc_lt_bw = 0;
3042 	bbr_reset_lt_bw_interval(bbr, cts);
3043 }
3044 
3045 static inline void
3046 bbr_lt_bw_samp_done(struct tcp_bbr *bbr, uint64_t bw, uint32_t cts, uint32_t timin)
3047 {
3048 	uint64_t diff;
3049 
3050 	/* Do we have a previous sample? */
3051 	if (bbr->r_ctl.rc_lt_bw) {
3052 		/* Get the diff in bytes per second */
3053 		if (bbr->r_ctl.rc_lt_bw > bw)
3054 			diff = bbr->r_ctl.rc_lt_bw - bw;
3055 		else
3056 			diff = bw - bbr->r_ctl.rc_lt_bw;
3057 		if ((diff <= bbr_lt_bw_diff) ||
3058 		    (diff <= (bbr->r_ctl.rc_lt_bw / bbr_lt_bw_ratio))) {
3059 			/* Consider us policed */
3060 			uint32_t saved_bw;
3061 
3062 			saved_bw = (uint32_t)bbr->r_ctl.rc_lt_bw;
3063 			bbr->r_ctl.rc_lt_bw = (bw + bbr->r_ctl.rc_lt_bw) / 2;	/* average of two */
3064 			bbr->rc_lt_use_bw = 1;
3065 			bbr->r_ctl.rc_bbr_hptsi_gain = BBR_UNIT;
3066 			/*
3067 			 * Use pkt based epoch for measuring length of
3068 			 * policer up
3069 			 */
3070 			bbr->r_ctl.rc_lt_epoch_use = bbr->r_ctl.rc_pkt_epoch;
3071 			/*
3072 			 * reason 4 is we need to start consider being
3073 			 * policed
3074 			 */
3075 			bbr_log_type_ltbw(bbr, cts, 4, (uint32_t)bw, saved_bw, (uint32_t)diff, timin);
3076 			return;
3077 		}
3078 	}
3079 	bbr->r_ctl.rc_lt_bw = bw;
3080 	bbr_reset_lt_bw_interval(bbr, cts);
3081 	bbr_log_type_ltbw(bbr, cts, 5, 0, (uint32_t)bw, 0, timin);
3082 }
3083 
3084 static void
3085 bbr_randomize_extra_state_time(struct tcp_bbr *bbr)
3086 {
3087 	uint32_t ran, deduct;
3088 
3089 	ran = arc4random_uniform(bbr_rand_ot);
3090 	if (ran) {
3091 		deduct = bbr->r_ctl.rc_level_state_extra / ran;
3092 		bbr->r_ctl.rc_level_state_extra -= deduct;
3093 	}
3094 }
3095 /*
3096  * Return randomly the starting state
3097  * to use in probebw.
3098  */
3099 static uint8_t
3100 bbr_pick_probebw_substate(struct tcp_bbr *bbr, uint32_t cts)
3101 {
3102 	uint32_t ran;
3103 	uint8_t ret_val;
3104 
3105 	/* Initialize the offset to 0 */
3106 	bbr->r_ctl.rc_exta_time_gd = 0;
3107 	bbr->rc_hit_state_1 = 0;
3108 	bbr->r_ctl.rc_level_state_extra = 0;
3109 	ran = arc4random_uniform((BBR_SUBSTATE_COUNT-1));
3110 	/*
3111 	 * The math works funny here :) the return value is used to set the
3112 	 * substate and then the state change is called which increments by
3113 	 * one. So if we return 1 (DRAIN) we will increment to 2 (LEVEL1) when
3114 	 * we fully enter the state. Note that the (8 - 1 - ran) assures that
3115 	 * we return 1 - 7, so we dont return 0 and end up starting in
3116 	 * state 1 (DRAIN).
3117 	 */
3118 	ret_val = BBR_SUBSTATE_COUNT - 1 - ran;
3119 	/* Set an epoch */
3120 	if ((cts - bbr->r_ctl.rc_rcv_epoch_start) >= bbr_get_rtt(bbr, BBR_RTT_PROP))
3121 		bbr_set_epoch(bbr, cts, __LINE__);
3122 
3123 	bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
3124 	return (ret_val);
3125 }
3126 
3127 static void
3128 bbr_lt_bw_sampling(struct tcp_bbr *bbr, uint32_t cts, int32_t loss_detected)
3129 {
3130 	uint32_t diff, d_time;
3131 	uint64_t del_time, bw, lost, delivered;
3132 
3133 	if (bbr->r_use_policer == 0)
3134 		return;
3135 	if (bbr->rc_lt_use_bw) {
3136 		/* We are using lt bw do we stop yet? */
3137 		diff = bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_lt_epoch_use;
3138 		if (diff > bbr_lt_bw_max_rtts) {
3139 			/* Reset it all */
3140 reset_all:
3141 			bbr_reset_lt_bw_sampling(bbr, cts);
3142 			if (bbr->rc_filled_pipe) {
3143 				bbr_set_epoch(bbr, cts, __LINE__);
3144 				bbr->rc_bbr_substate = bbr_pick_probebw_substate(bbr, cts);
3145 				bbr_substate_change(bbr, cts, __LINE__, 0);
3146 				bbr->rc_bbr_state = BBR_STATE_PROBE_BW;
3147 				bbr_log_type_statechange(bbr, cts, __LINE__);
3148 			} else {
3149 				/*
3150 				 * This should not happen really
3151 				 * unless we remove the startup/drain
3152 				 * restrictions above.
3153 				 */
3154 				bbr->rc_bbr_state = BBR_STATE_STARTUP;
3155 				bbr_set_epoch(bbr, cts, __LINE__);
3156 				bbr->r_ctl.rc_bbr_state_time = cts;
3157 				bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
3158 				bbr->r_ctl.rc_bbr_hptsi_gain = bbr->r_ctl.rc_startup_pg;
3159 				bbr->r_ctl.rc_bbr_cwnd_gain = bbr->r_ctl.rc_startup_pg;
3160 				bbr_set_state_target(bbr, __LINE__);
3161 				bbr_log_type_statechange(bbr, cts, __LINE__);
3162 			}
3163 			/* reason 0 is to stop using lt-bw */
3164 			bbr_log_type_ltbw(bbr, cts, 0, 0, 0, 0, 0);
3165 			return;
3166 		}
3167 		if (bbr_lt_intvl_fp == 0) {
3168 			/* Not doing false-postive detection */
3169 			return;
3170 		}
3171 		/* False positive detection */
3172 		if (diff == bbr_lt_intvl_fp) {
3173 			/* At bbr_lt_intvl_fp we record the lost */
3174 			bbr->r_ctl.rc_lt_del = bbr->r_ctl.rc_delivered;
3175 			bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
3176 		} else if (diff > (bbr_lt_intvl_min_rtts + bbr_lt_intvl_fp)) {
3177 			/* Now is our loss rate still high? */
3178 			lost = bbr->r_ctl.rc_lost - bbr->r_ctl.rc_lt_lost;
3179 			delivered = bbr->r_ctl.rc_delivered - bbr->r_ctl.rc_lt_del;
3180 			if ((delivered == 0) ||
3181 			    (((lost * 1000)/delivered) < bbr_lt_fd_thresh)) {
3182 				/* No still below our threshold */
3183 				bbr_log_type_ltbw(bbr, cts, 7, lost, delivered, 0, 0);
3184 			} else {
3185 				/* Yikes its still high, it must be a false positive */
3186 				bbr_log_type_ltbw(bbr, cts, 8, lost, delivered, 0, 0);
3187 				goto reset_all;
3188 			}
3189 		}
3190 		return;
3191 	}
3192 	/*
3193 	 * Wait for the first loss before sampling, to let the policer
3194 	 * exhaust its tokens and estimate the steady-state rate allowed by
3195 	 * the policer. Starting samples earlier includes bursts that
3196 	 * over-estimate the bw.
3197 	 */
3198 	if (bbr->rc_lt_is_sampling == 0) {
3199 		/* reason 1 is to begin doing the sampling  */
3200 		if (loss_detected == 0)
3201 			return;
3202 		bbr_reset_lt_bw_interval(bbr, cts);
3203 		bbr->rc_lt_is_sampling = 1;
3204 		bbr_log_type_ltbw(bbr, cts, 1, 0, 0, 0, 0);
3205 		return;
3206 	}
3207 	/* Now how long were we delivering long term last> */
3208 	if (TSTMP_GEQ(bbr->r_ctl.rc_del_time, bbr->r_ctl.rc_lt_time))
3209 		d_time = bbr->r_ctl.rc_del_time - bbr->r_ctl.rc_lt_time;
3210 	else
3211 		d_time = 0;
3212 
3213 	/* To avoid underestimates, reset sampling if we run out of data. */
3214 	if (bbr->r_ctl.r_app_limited_until) {
3215 		/* Can not measure in app-limited state */
3216 		bbr_reset_lt_bw_sampling(bbr, cts);
3217 		/* reason 2 is to reset sampling due to app limits  */
3218 		bbr_log_type_ltbw(bbr, cts, 2, 0, 0, 0, d_time);
3219 		return;
3220 	}
3221 	diff = bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_lt_epoch;
3222 	if (diff < bbr_lt_intvl_min_rtts) {
3223 		/*
3224 		 * need more samples (we don't
3225 		 * start on a round like linux so
3226 		 * we need 1 more).
3227 		 */
3228 		/* 6 is not_enough time or no-loss */
3229 		bbr_log_type_ltbw(bbr, cts, 6, 0, 0, 0, d_time);
3230 		return;
3231 	}
3232 	if (diff > (4 * bbr_lt_intvl_min_rtts)) {
3233 		/*
3234 		 * For now if we wait too long, reset all sampling. We need
3235 		 * to do some research here, its possible that we should
3236 		 * base this on how much loss as occurred.. something like
3237 		 * if its under 10% (or some thresh) reset all otherwise
3238 		 * don't.  Thats for phase II I guess.
3239 		 */
3240 		bbr_reset_lt_bw_sampling(bbr, cts);
3241  		/* reason 3 is to reset sampling due too long of sampling */
3242 		bbr_log_type_ltbw(bbr, cts, 3, 0, 0, 0, d_time);
3243 		return;
3244 	}
3245 	/*
3246 	 * End sampling interval when a packet is lost, so we estimate the
3247 	 * policer tokens were exhausted. Stopping the sampling before the
3248 	 * tokens are exhausted under-estimates the policed rate.
3249 	 */
3250 	if (loss_detected == 0) {
3251 		/* 6 is not_enough time or no-loss */
3252 		bbr_log_type_ltbw(bbr, cts, 6, 0, 0, 0, d_time);
3253 		return;
3254 	}
3255 	/* Calculate packets lost and delivered in sampling interval. */
3256 	lost = bbr->r_ctl.rc_lost - bbr->r_ctl.rc_lt_lost;
3257 	delivered = bbr->r_ctl.rc_delivered - bbr->r_ctl.rc_lt_del;
3258 	if ((delivered == 0) ||
3259 	    (((lost * 1000)/delivered) < bbr_lt_loss_thresh)) {
3260 		bbr_log_type_ltbw(bbr, cts, 6, lost, delivered, 0, d_time);
3261 		return;
3262 	}
3263 	if (d_time < 1000) {
3264 		/* Not enough time. wait */
3265 		/* 6 is not_enough time or no-loss */
3266 		bbr_log_type_ltbw(bbr, cts, 6, 0, 0, 0, d_time);
3267 		return;
3268 	}
3269 	if (d_time >= (0xffffffff / USECS_IN_MSEC)) {
3270 		/* Too long */
3271 		bbr_reset_lt_bw_sampling(bbr, cts);
3272  		/* reason 3 is to reset sampling due too long of sampling */
3273 		bbr_log_type_ltbw(bbr, cts, 3, 0, 0, 0, d_time);
3274 		return;
3275 	}
3276 	del_time = d_time;
3277 	bw = delivered;
3278 	bw *= (uint64_t)USECS_IN_SECOND;
3279 	bw /= del_time;
3280 	bbr_lt_bw_samp_done(bbr, bw, cts, d_time);
3281 }
3282 
3283 /*
3284  * Allocate a sendmap from our zone.
3285  */
3286 static struct bbr_sendmap *
3287 bbr_alloc(struct tcp_bbr *bbr)
3288 {
3289 	struct bbr_sendmap *rsm;
3290 
3291 	BBR_STAT_INC(bbr_to_alloc);
3292 	rsm = uma_zalloc(bbr_zone, (M_NOWAIT | M_ZERO));
3293 	if (rsm) {
3294 		bbr->r_ctl.rc_num_maps_alloced++;
3295 		return (rsm);
3296 	}
3297 	if (bbr->r_ctl.rc_free_cnt) {
3298 		BBR_STAT_INC(bbr_to_alloc_emerg);
3299 		rsm = TAILQ_FIRST(&bbr->r_ctl.rc_free);
3300 		TAILQ_REMOVE(&bbr->r_ctl.rc_free, rsm, r_next);
3301 		bbr->r_ctl.rc_free_cnt--;
3302 		return (rsm);
3303 	}
3304 	BBR_STAT_INC(bbr_to_alloc_failed);
3305 	return (NULL);
3306 }
3307 
3308 static struct bbr_sendmap *
3309 bbr_alloc_full_limit(struct tcp_bbr *bbr)
3310 {
3311 	if ((V_tcp_map_entries_limit > 0) &&
3312 	    (bbr->r_ctl.rc_num_maps_alloced >= V_tcp_map_entries_limit)) {
3313 		BBR_STAT_INC(bbr_alloc_limited);
3314 		if (!bbr->alloc_limit_reported) {
3315 			bbr->alloc_limit_reported = 1;
3316 			BBR_STAT_INC(bbr_alloc_limited_conns);
3317 		}
3318 		return (NULL);
3319 	}
3320 	return (bbr_alloc(bbr));
3321 }
3322 
3323 /* wrapper to allocate a sendmap entry, subject to a specific limit */
3324 static struct bbr_sendmap *
3325 bbr_alloc_limit(struct tcp_bbr *bbr, uint8_t limit_type)
3326 {
3327 	struct bbr_sendmap *rsm;
3328 
3329 	if (limit_type) {
3330 		/* currently there is only one limit type */
3331 		if (V_tcp_map_split_limit > 0 &&
3332 		    bbr->r_ctl.rc_num_split_allocs >= V_tcp_map_split_limit) {
3333 			BBR_STAT_INC(bbr_split_limited);
3334 			if (!bbr->alloc_limit_reported) {
3335 				bbr->alloc_limit_reported = 1;
3336 				BBR_STAT_INC(bbr_alloc_limited_conns);
3337 			}
3338 			return (NULL);
3339 		}
3340 	}
3341 
3342 	/* allocate and mark in the limit type, if set */
3343 	rsm = bbr_alloc(bbr);
3344 	if (rsm != NULL && limit_type) {
3345 		rsm->r_limit_type = limit_type;
3346 		bbr->r_ctl.rc_num_split_allocs++;
3347 	}
3348 	return (rsm);
3349 }
3350 
3351 static void
3352 bbr_free(struct tcp_bbr *bbr, struct bbr_sendmap *rsm)
3353 {
3354 	if (rsm->r_limit_type) {
3355 		/* currently there is only one limit type */
3356 		bbr->r_ctl.rc_num_split_allocs--;
3357 	}
3358 	if (rsm->r_is_smallmap)
3359 		bbr->r_ctl.rc_num_small_maps_alloced--;
3360 	if (bbr->r_ctl.rc_tlp_send == rsm)
3361 		bbr->r_ctl.rc_tlp_send = NULL;
3362 	if (bbr->r_ctl.rc_resend == rsm) {
3363 		bbr->r_ctl.rc_resend = NULL;
3364 	}
3365 	if (bbr->r_ctl.rc_next == rsm)
3366 		bbr->r_ctl.rc_next = NULL;
3367 	if (bbr->r_ctl.rc_sacklast == rsm)
3368 		bbr->r_ctl.rc_sacklast = NULL;
3369 	if (bbr->r_ctl.rc_free_cnt < bbr_min_req_free) {
3370 		memset(rsm, 0, sizeof(struct bbr_sendmap));
3371 		TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_free, rsm, r_next);
3372 		rsm->r_limit_type = 0;
3373 		bbr->r_ctl.rc_free_cnt++;
3374 		return;
3375 	}
3376 	bbr->r_ctl.rc_num_maps_alloced--;
3377 	uma_zfree(bbr_zone, rsm);
3378 }
3379 
3380 /*
3381  * Returns the BDP.
3382  */
3383 static uint64_t
3384 bbr_get_bw_delay_prod(uint64_t rtt, uint64_t bw) {
3385 	/*
3386 	 * Calculate the bytes in flight needed given the bw (in bytes per
3387 	 * second) and the specifyed rtt in useconds. We need to put out the
3388 	 * returned value per RTT to match that rate. Gain will normaly
3389 	 * raise it up from there.
3390 	 *
3391 	 * This should not overflow as long as the bandwidth is below 1
3392 	 * TByte per second (bw < 10**12 = 2**40) and the rtt is smaller
3393 	 * than 1000 seconds (rtt < 10**3 * 10**6 = 10**9 = 2**30).
3394 	 */
3395 	uint64_t usec_per_sec;
3396 
3397 	usec_per_sec = USECS_IN_SECOND;
3398 	return ((rtt * bw) / usec_per_sec);
3399 }
3400 
3401 /*
3402  * Return the initial cwnd.
3403  */
3404 static uint32_t
3405 bbr_initial_cwnd(struct tcp_bbr *bbr, struct tcpcb *tp)
3406 {
3407 	uint32_t i_cwnd;
3408 
3409 	if (bbr->rc_init_win) {
3410 		i_cwnd = bbr->rc_init_win * tp->t_maxseg;
3411 	} else if (V_tcp_initcwnd_segments)
3412 		i_cwnd = min((V_tcp_initcwnd_segments * tp->t_maxseg),
3413 		    max(2 * tp->t_maxseg, 14600));
3414 	else if (V_tcp_do_rfc3390)
3415 		i_cwnd = min(4 * tp->t_maxseg,
3416 		    max(2 * tp->t_maxseg, 4380));
3417 	else {
3418 		/* Per RFC5681 Section 3.1 */
3419 		if (tp->t_maxseg > 2190)
3420 			i_cwnd = 2 * tp->t_maxseg;
3421 		else if (tp->t_maxseg > 1095)
3422 			i_cwnd = 3 * tp->t_maxseg;
3423 		else
3424 			i_cwnd = 4 * tp->t_maxseg;
3425 	}
3426 	return (i_cwnd);
3427 }
3428 
3429 /*
3430  * Given a specified gain, return the target
3431  * cwnd based on that gain.
3432  */
3433 static uint32_t
3434 bbr_get_raw_target_cwnd(struct tcp_bbr *bbr, uint32_t gain, uint64_t bw)
3435 {
3436 	uint64_t bdp, rtt;
3437 	uint32_t cwnd;
3438 
3439 	if ((get_filter_value_small(&bbr->r_ctl.rc_rttprop) == 0xffffffff) ||
3440 	    (bbr_get_full_bw(bbr) == 0)) {
3441 		/* No measurements yet */
3442 		return (bbr_initial_cwnd(bbr, bbr->rc_tp));
3443 	}
3444 	/*
3445 	 * Get bytes per RTT needed (rttProp is normally in
3446 	 * bbr_cwndtarget_rtt_touse)
3447 	 */
3448 	rtt = bbr_get_rtt(bbr, bbr_cwndtarget_rtt_touse);
3449 	/* Get the bdp from the two values */
3450 	bdp = bbr_get_bw_delay_prod(rtt, bw);
3451 	/* Now apply the gain */
3452 	cwnd = (uint32_t)(((bdp * ((uint64_t)gain)) + (uint64_t)(BBR_UNIT - 1)) / ((uint64_t)BBR_UNIT));
3453 
3454 	return (cwnd);
3455 }
3456 
3457 static uint32_t
3458 bbr_get_target_cwnd(struct tcp_bbr *bbr, uint64_t bw, uint32_t gain)
3459 {
3460 	uint32_t cwnd, mss;
3461 
3462 	mss = min((bbr->rc_tp->t_maxseg - bbr->rc_last_options), bbr->r_ctl.rc_pace_max_segs);
3463 	/* Get the base cwnd with gain rounded to a mss */
3464 	cwnd = roundup(bbr_get_raw_target_cwnd(bbr, bw, gain), mss);
3465 	/*
3466 	 * Add in N (2 default since we do not have a
3467 	 * fq layer to trap packets in) quanta's per the I-D
3468 	 * section 4.2.3.2 quanta adjust.
3469 	 */
3470 	cwnd += (bbr_quanta * bbr->r_ctl.rc_pace_max_segs);
3471 	if (bbr->rc_use_google) {
3472 		if((bbr->rc_bbr_state == BBR_STATE_PROBE_BW) &&
3473 		   (bbr_state_val(bbr) == BBR_SUB_GAIN)) {
3474 			/*
3475 			 * The linux implementation adds
3476 			 * an extra 2 x mss in gain cycle which
3477 			 * is documented no-where except in the code.
3478 			 * so we add more for Neal undocumented feature
3479 			 */
3480 			cwnd += 2 * mss;
3481 		}
3482  		if ((cwnd / mss) & 0x1) {
3483 			/* Round up for odd num mss */
3484 			cwnd += mss;
3485 		}
3486 	}
3487 	/* Are we below the min cwnd? */
3488 	if (cwnd < get_min_cwnd(bbr))
3489 		return (get_min_cwnd(bbr));
3490 	return (cwnd);
3491 }
3492 
3493 static uint16_t
3494 bbr_gain_adjust(struct tcp_bbr *bbr, uint16_t gain)
3495 {
3496 	if (gain < 1)
3497 		gain = 1;
3498 	return (gain);
3499 }
3500 
3501 static uint32_t
3502 bbr_get_header_oh(struct tcp_bbr *bbr)
3503 {
3504 	int seg_oh;
3505 
3506 	seg_oh = 0;
3507 	if (bbr->r_ctl.rc_inc_tcp_oh) {
3508 		/* Do we include TCP overhead? */
3509 		seg_oh = (bbr->rc_last_options + sizeof(struct tcphdr));
3510 	}
3511 	if (bbr->r_ctl.rc_inc_ip_oh) {
3512 		/* Do we include IP overhead? */
3513 #ifdef INET6
3514 		if (bbr->r_is_v6)
3515 			seg_oh += sizeof(struct ip6_hdr);
3516 		else
3517 #endif
3518 #ifdef INET
3519 			seg_oh += sizeof(struct ip);
3520 #endif
3521 	}
3522 	if (bbr->r_ctl.rc_inc_enet_oh) {
3523 		/* Do we include the ethernet overhead?  */
3524 		seg_oh += sizeof(struct ether_header);
3525 	}
3526 	return(seg_oh);
3527 }
3528 
3529 static uint32_t
3530 bbr_get_pacing_length(struct tcp_bbr *bbr, uint16_t gain, uint32_t useconds_time, uint64_t bw)
3531 {
3532 	uint64_t divor, res, tim;
3533 
3534 	if (useconds_time == 0)
3535 		return (0);
3536 	gain = bbr_gain_adjust(bbr, gain);
3537 	divor = (uint64_t)USECS_IN_SECOND * (uint64_t)BBR_UNIT;
3538 	tim = useconds_time;
3539 	res = (tim * bw * gain) / divor;
3540 	if (res == 0)
3541 		res = 1;
3542 	return ((uint32_t)res);
3543 }
3544 
3545 /*
3546  * Given a gain and a length return the delay in useconds that
3547  * should be used to evenly space out packets
3548  * on the connection (based on the gain factor).
3549  */
3550 static uint32_t
3551 bbr_get_pacing_delay(struct tcp_bbr *bbr, uint16_t gain, int32_t len, uint32_t cts, int nolog)
3552 {
3553 	uint64_t bw, lentim, res;
3554 	uint32_t usecs, srtt, over = 0;
3555 	uint32_t seg_oh, num_segs, maxseg;
3556 
3557 	if (len == 0)
3558 		return (0);
3559 
3560 	maxseg = bbr->rc_tp->t_maxseg - bbr->rc_last_options;
3561 	num_segs = (len + maxseg - 1) / maxseg;
3562 	if (bbr->rc_use_google == 0) {
3563 		seg_oh = bbr_get_header_oh(bbr);
3564 		len += (num_segs * seg_oh);
3565 	}
3566 	gain = bbr_gain_adjust(bbr, gain);
3567 	bw = bbr_get_bw(bbr);
3568 	if (bbr->rc_use_google) {
3569 		uint64_t cbw;
3570 
3571 		/*
3572 		 * Reduce the b/w by the google discount
3573 		 * factor 10 = 1%.
3574 		 */
3575 		cbw = bw *  (uint64_t)(1000 - bbr->r_ctl.bbr_google_discount);
3576 		cbw /= (uint64_t)1000;
3577 		/* We don't apply a discount if it results in 0 */
3578 		if (cbw > 0)
3579 			bw = cbw;
3580 	}
3581 	lentim = ((uint64_t)len *
3582 		  (uint64_t)USECS_IN_SECOND *
3583 		  (uint64_t)BBR_UNIT);
3584 	res = lentim / ((uint64_t)gain * bw);
3585 	if (res == 0)
3586 		res = 1;
3587 	usecs = (uint32_t)res;
3588 	srtt = bbr_get_rtt(bbr, BBR_SRTT);
3589 	if (bbr_hptsi_max_mul && bbr_hptsi_max_div &&
3590 	    (bbr->rc_use_google == 0) &&
3591 	    (usecs > ((srtt * bbr_hptsi_max_mul) / bbr_hptsi_max_div))) {
3592 		/*
3593 		 * We cannot let the delay be more than 1/2 the srtt time.
3594 		 * Otherwise we cannot pace out or send properly.
3595 		 */
3596 		over = usecs = (srtt * bbr_hptsi_max_mul) / bbr_hptsi_max_div;
3597 		BBR_STAT_INC(bbr_hpts_min_time);
3598 	}
3599 	if (!nolog)
3600 		bbr_log_pacing_delay_calc(bbr, gain, len, cts, usecs, bw, over, 1);
3601 	return (usecs);
3602 }
3603 
3604 static void
3605 bbr_ack_received(struct tcpcb *tp, struct tcp_bbr *bbr, struct tcphdr *th, uint32_t bytes_this_ack,
3606 		 uint32_t sack_changed, uint32_t prev_acked, int32_t line, uint32_t losses)
3607 {
3608 	INP_WLOCK_ASSERT(tp->t_inpcb);
3609 	uint64_t bw;
3610 	uint32_t cwnd, target_cwnd, saved_bytes, maxseg;
3611 	int32_t meth;
3612 
3613 #ifdef STATS
3614 	if ((tp->t_flags & TF_GPUTINPROG) &&
3615 	    SEQ_GEQ(th->th_ack, tp->gput_ack)) {
3616 		/*
3617 		 * Strech acks and compressed acks will cause this to
3618 		 * oscillate but we are doing it the same way as the main
3619 		 * stack so it will be compariable (though possibly not
3620 		 * ideal).
3621 		 */
3622 		int32_t cgput;
3623 		int64_t gput, time_stamp;
3624 
3625 		gput = (int64_t) (th->th_ack - tp->gput_seq) * 8;
3626 		time_stamp = max(1, ((bbr->r_ctl.rc_rcvtime - tp->gput_ts) / 1000));
3627 		cgput = gput / time_stamp;
3628 		stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_GPUT,
3629 					 cgput);
3630 		if (tp->t_stats_gput_prev > 0)
3631 			stats_voi_update_abs_s32(tp->t_stats,
3632 						 VOI_TCP_GPUT_ND,
3633 						 ((gput - tp->t_stats_gput_prev) * 100) /
3634 						 tp->t_stats_gput_prev);
3635 		tp->t_flags &= ~TF_GPUTINPROG;
3636 		tp->t_stats_gput_prev = cgput;
3637 	}
3638 #endif
3639 	if ((bbr->rc_bbr_state == BBR_STATE_PROBE_RTT) &&
3640 	    ((bbr->r_ctl.bbr_rttprobe_gain_val == 0) || bbr->rc_use_google)) {
3641 		/* We don't change anything in probe-rtt */
3642 		return;
3643 	}
3644 	maxseg = tp->t_maxseg - bbr->rc_last_options;
3645 	saved_bytes = bytes_this_ack;
3646 	bytes_this_ack += sack_changed;
3647 	if (bytes_this_ack > prev_acked) {
3648 		bytes_this_ack -= prev_acked;
3649 		/*
3650 		 * A byte ack'd gives us a full mss
3651 		 * to be like linux i.e. they count packets.
3652 		 */
3653 		if ((bytes_this_ack < maxseg) && bbr->rc_use_google)
3654 			bytes_this_ack = maxseg;
3655 	} else {
3656 		/* Unlikely */
3657 		bytes_this_ack = 0;
3658 	}
3659 	cwnd = tp->snd_cwnd;
3660 	bw = get_filter_value(&bbr->r_ctl.rc_delrate);
3661 	if (bw)
3662 		target_cwnd = bbr_get_target_cwnd(bbr,
3663 						  bw,
3664 						  (uint32_t)bbr->r_ctl.rc_bbr_cwnd_gain);
3665 	else
3666 		target_cwnd = bbr_initial_cwnd(bbr, bbr->rc_tp);
3667 	if (IN_RECOVERY(tp->t_flags) &&
3668 	    (bbr->bbr_prev_in_rec == 0)) {
3669 		/*
3670 		 * We are entering recovery and
3671 		 * thus packet conservation.
3672 		 */
3673 		bbr->pkt_conservation = 1;
3674 		bbr->r_ctl.rc_recovery_start = bbr->r_ctl.rc_rcvtime;
3675 		cwnd = ctf_flight_size(tp,
3676 				       (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes)) +
3677 			bytes_this_ack;
3678 	}
3679 	if (IN_RECOVERY(tp->t_flags)) {
3680 		uint32_t flight;
3681 
3682 		bbr->bbr_prev_in_rec = 1;
3683 		if (cwnd > losses) {
3684 			cwnd -= losses;
3685 			if (cwnd < maxseg)
3686 				cwnd = maxseg;
3687 		} else
3688 			cwnd = maxseg;
3689 		flight = ctf_flight_size(tp,
3690 					 (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
3691 		bbr_log_type_cwndupd(bbr, flight, 0,
3692 				     losses, 10, 0, 0, line);
3693 		if (bbr->pkt_conservation) {
3694 			uint32_t time_in;
3695 
3696 			if (TSTMP_GEQ(bbr->r_ctl.rc_rcvtime, bbr->r_ctl.rc_recovery_start))
3697 				time_in = bbr->r_ctl.rc_rcvtime - bbr->r_ctl.rc_recovery_start;
3698 			else
3699 				time_in = 0;
3700 
3701 			if (time_in >= bbr_get_rtt(bbr, BBR_RTT_PROP)) {
3702 				/* Clear packet conservation after an rttProp */
3703 				bbr->pkt_conservation = 0;
3704 			} else {
3705 				if ((flight + bytes_this_ack) > cwnd)
3706 					cwnd = flight + bytes_this_ack;
3707 				if (cwnd < get_min_cwnd(bbr))
3708 					cwnd = get_min_cwnd(bbr);
3709 				tp->snd_cwnd = cwnd;
3710 				bbr_log_type_cwndupd(bbr, saved_bytes, sack_changed,
3711 						     prev_acked, 1, target_cwnd, th->th_ack, line);
3712 				return;
3713 			}
3714 		}
3715 	} else
3716 		bbr->bbr_prev_in_rec = 0;
3717 	if ((bbr->rc_use_google == 0) && bbr->r_ctl.restrict_growth) {
3718 		bbr->r_ctl.restrict_growth--;
3719 		if (bytes_this_ack > maxseg)
3720 			bytes_this_ack = maxseg;
3721 	}
3722 	if (bbr->rc_filled_pipe) {
3723 		/*
3724 		 * Here we have exited startup and filled the pipe. We will
3725 		 * thus allow the cwnd to shrink to the target. We hit here
3726 		 * mostly.
3727 		 */
3728 		uint32_t s_cwnd;
3729 
3730 		meth = 2;
3731 		s_cwnd = min((cwnd + bytes_this_ack), target_cwnd);
3732 		if (s_cwnd > cwnd)
3733 			cwnd = s_cwnd;
3734 		else if (bbr_cwnd_may_shrink || bbr->rc_use_google || bbr->rc_no_pacing)
3735 			cwnd = s_cwnd;
3736 	} else {
3737 		/*
3738 		 * Here we are still in startup, we increase cwnd by what
3739 		 * has been acked.
3740 		 */
3741 		if ((cwnd < target_cwnd) ||
3742 		    (bbr->rc_past_init_win == 0)) {
3743 			meth = 3;
3744 			cwnd += bytes_this_ack;
3745 		} else {
3746 			/*
3747 			 * Method 4 means we are at target so no gain in
3748 			 * startup and past the initial window.
3749 			 */
3750 			meth = 4;
3751 		}
3752 	}
3753 	tp->snd_cwnd = max(cwnd, get_min_cwnd(bbr));
3754 	bbr_log_type_cwndupd(bbr, saved_bytes, sack_changed, prev_acked, meth, target_cwnd, th->th_ack, line);
3755 }
3756 
3757 static void
3758 tcp_bbr_partialack(struct tcpcb *tp)
3759 {
3760 	struct tcp_bbr *bbr;
3761 
3762 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
3763 	INP_WLOCK_ASSERT(tp->t_inpcb);
3764 	if (ctf_flight_size(tp,
3765 		(bbr->r_ctl.rc_sacked  + bbr->r_ctl.rc_lost_bytes)) <=
3766 	    tp->snd_cwnd) {
3767 		bbr->r_wanted_output = 1;
3768 	}
3769 }
3770 
3771 static void
3772 bbr_post_recovery(struct tcpcb *tp)
3773 {
3774 	struct tcp_bbr *bbr;
3775 	uint32_t  flight;
3776 
3777 	INP_WLOCK_ASSERT(tp->t_inpcb);
3778 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
3779 	/*
3780 	 * Here we just exit recovery.
3781 	 */
3782 	EXIT_RECOVERY(tp->t_flags);
3783 	/* Lock in our b/w reduction for the specified number of pkt-epochs */
3784 	bbr->r_recovery_bw = 0;
3785 	tp->snd_recover = tp->snd_una;
3786 	tcp_bbr_tso_size_check(bbr, bbr->r_ctl.rc_rcvtime);
3787 	bbr->pkt_conservation = 0;
3788 	if (bbr->rc_use_google == 0) {
3789 		/*
3790 		 * For non-google mode lets
3791 		 * go ahead and make sure we clear
3792 		 * the recovery state so if we
3793 		 * bounce back in to recovery we
3794 		 * will do PC.
3795 		 */
3796 		bbr->bbr_prev_in_rec = 0;
3797 	}
3798 	bbr_log_type_exit_rec(bbr);
3799 	if (bbr->rc_bbr_state != BBR_STATE_PROBE_RTT) {
3800 		tp->snd_cwnd = max(tp->snd_cwnd, bbr->r_ctl.rc_cwnd_on_ent);
3801 		bbr_log_type_cwndupd(bbr, 0, 0, 0, 15, 0, 0, __LINE__);
3802 	} else {
3803 		/* For probe-rtt case lets fix up its saved_cwnd */
3804 		if (bbr->r_ctl.rc_saved_cwnd < bbr->r_ctl.rc_cwnd_on_ent) {
3805 			bbr->r_ctl.rc_saved_cwnd = bbr->r_ctl.rc_cwnd_on_ent;
3806 			bbr_log_type_cwndupd(bbr, 0, 0, 0, 16, 0, 0, __LINE__);
3807 		}
3808 	}
3809 	flight = ctf_flight_size(tp,
3810 		     (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
3811 	if ((bbr->rc_use_google == 0) &&
3812 	    bbr_do_red) {
3813 		uint64_t val, lr2use;
3814 		uint32_t maxseg, newcwnd, acks_inflight, ratio, cwnd;
3815 		uint32_t *cwnd_p;
3816 
3817 		if (bbr_get_rtt(bbr, BBR_SRTT)) {
3818 			val = ((uint64_t)bbr_get_rtt(bbr, BBR_RTT_PROP) * (uint64_t)1000);
3819 			val /= bbr_get_rtt(bbr, BBR_SRTT);
3820 			ratio = (uint32_t)val;
3821 		} else
3822 			ratio = 1000;
3823 
3824 		bbr_log_type_cwndupd(bbr, bbr_red_mul, bbr_red_div,
3825 				     bbr->r_ctl.recovery_lr, 21,
3826 				     ratio,
3827 				     bbr->r_ctl.rc_red_cwnd_pe,
3828 				     __LINE__);
3829 		if ((ratio < bbr_do_red) || (bbr_do_red == 0))
3830 			goto done;
3831 		if (((bbr->rc_bbr_state == BBR_STATE_PROBE_RTT) &&
3832 		     bbr_prtt_slam_cwnd) ||
3833 		    (bbr_sub_drain_slam_cwnd &&
3834 		     (bbr->rc_bbr_state == BBR_STATE_PROBE_BW) &&
3835 		     bbr->rc_hit_state_1 &&
3836 		     (bbr_state_val(bbr) == BBR_SUB_DRAIN)) ||
3837 		    ((bbr->rc_bbr_state == BBR_STATE_DRAIN) &&
3838 		     bbr_slam_cwnd_in_main_drain)) {
3839 			/*
3840 			 * Here we must poke at the saved cwnd
3841 			 * as well as the cwnd.
3842 			 */
3843 			cwnd = bbr->r_ctl.rc_saved_cwnd;
3844 			cwnd_p = &bbr->r_ctl.rc_saved_cwnd;
3845 		} else {
3846  			cwnd = tp->snd_cwnd;
3847 			cwnd_p = &tp->snd_cwnd;
3848 		}
3849 		maxseg = tp->t_maxseg - bbr->rc_last_options;
3850 		/* Add the overall lr with the recovery lr */
3851 		if (bbr->r_ctl.rc_lost == 0)
3852 			lr2use = 0;
3853 		else if (bbr->r_ctl.rc_delivered == 0)
3854 			lr2use = 1000;
3855 		else {
3856 			lr2use = bbr->r_ctl.rc_lost * 1000;
3857 			lr2use /= bbr->r_ctl.rc_delivered;
3858 		}
3859 		lr2use += bbr->r_ctl.recovery_lr;
3860 		acks_inflight = (flight / (maxseg * 2));
3861 		if (bbr_red_scale) {
3862 			lr2use *= bbr_get_rtt(bbr, BBR_SRTT);
3863 			lr2use /= bbr_red_scale;
3864 			if ((bbr_red_growth_restrict) &&
3865 			    ((bbr_get_rtt(bbr, BBR_SRTT)/bbr_red_scale) > 1))
3866 			    bbr->r_ctl.restrict_growth += acks_inflight;
3867 		}
3868 		if (lr2use) {
3869 			val = (uint64_t)cwnd * lr2use;
3870 			val /= 1000;
3871 			if (cwnd > val)
3872 				newcwnd = roundup((cwnd - val), maxseg);
3873 			else
3874 				newcwnd = maxseg;
3875 		} else {
3876 			val = (uint64_t)cwnd * (uint64_t)bbr_red_mul;
3877 			val /= (uint64_t)bbr_red_div;
3878 			newcwnd = roundup((uint32_t)val, maxseg);
3879 		}
3880 		/* with standard delayed acks how many acks can I expect? */
3881 		if (bbr_drop_limit == 0) {
3882 			/*
3883 			 * Anticpate how much we will
3884 			 * raise the cwnd based on the acks.
3885 			 */
3886 			if ((newcwnd + (acks_inflight * maxseg)) < get_min_cwnd(bbr)) {
3887 				/* We do enforce the min (with the acks) */
3888 				newcwnd = (get_min_cwnd(bbr) - acks_inflight);
3889 			}
3890 		} else {
3891 			/*
3892 			 * A strict drop limit of N is is inplace
3893 			 */
3894 			if (newcwnd < (bbr_drop_limit * maxseg)) {
3895 				newcwnd = bbr_drop_limit * maxseg;
3896 			}
3897 		}
3898 		/* For the next N acks do we restrict the growth */
3899 		*cwnd_p = newcwnd;
3900 		if (tp->snd_cwnd > newcwnd)
3901 			tp->snd_cwnd = newcwnd;
3902 		bbr_log_type_cwndupd(bbr, bbr_red_mul, bbr_red_div, val, 22,
3903 				     (uint32_t)lr2use,
3904 				     bbr_get_rtt(bbr, BBR_SRTT), __LINE__);
3905 		bbr->r_ctl.rc_red_cwnd_pe = bbr->r_ctl.rc_pkt_epoch;
3906 	}
3907 done:
3908 	bbr->r_ctl.recovery_lr = 0;
3909 	if (flight <= tp->snd_cwnd) {
3910 		bbr->r_wanted_output = 1;
3911 	}
3912 	tcp_bbr_tso_size_check(bbr, bbr->r_ctl.rc_rcvtime);
3913 }
3914 
3915 static void
3916 bbr_setup_red_bw(struct tcp_bbr *bbr, uint32_t cts)
3917 {
3918 	bbr->r_ctl.red_bw = get_filter_value(&bbr->r_ctl.rc_delrate);
3919 	/* Limit the drop in b/w to 1/2 our current filter. */
3920 	if (bbr->r_ctl.red_bw > bbr->r_ctl.rc_bbr_cur_del_rate)
3921 		bbr->r_ctl.red_bw = bbr->r_ctl.rc_bbr_cur_del_rate;
3922 	if (bbr->r_ctl.red_bw < (get_filter_value(&bbr->r_ctl.rc_delrate) / 2))
3923 		bbr->r_ctl.red_bw = get_filter_value(&bbr->r_ctl.rc_delrate) / 2;
3924 	tcp_bbr_tso_size_check(bbr, cts);
3925 }
3926 
3927 static void
3928 bbr_cong_signal(struct tcpcb *tp, struct tcphdr *th, uint32_t type, struct bbr_sendmap *rsm)
3929 {
3930 	struct tcp_bbr *bbr;
3931 
3932 	INP_WLOCK_ASSERT(tp->t_inpcb);
3933 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
3934 	switch (type) {
3935 	case CC_NDUPACK:
3936 		if (!IN_RECOVERY(tp->t_flags)) {
3937 			tp->snd_recover = tp->snd_max;
3938 			/* Start a new epoch */
3939 			bbr_set_pktepoch(bbr, bbr->r_ctl.rc_rcvtime, __LINE__);
3940 			if (bbr->rc_lt_is_sampling || bbr->rc_lt_use_bw) {
3941 				/*
3942 				 * Move forward the lt epoch
3943 				 * so it won't count the truncated
3944 				 * epoch.
3945 				 */
3946 				bbr->r_ctl.rc_lt_epoch++;
3947 			}
3948 			if (bbr->rc_bbr_state == BBR_STATE_STARTUP) {
3949 				/*
3950 				 * Just like the policer detection code
3951 				 * if we are in startup we must push
3952 				 * forward the last startup epoch
3953 				 * to hide the truncated PE.
3954 				 */
3955 				bbr->r_ctl.rc_bbr_last_startup_epoch++;
3956 			}
3957 			bbr->r_ctl.rc_cwnd_on_ent = tp->snd_cwnd;
3958 			ENTER_RECOVERY(tp->t_flags);
3959 			bbr->rc_tlp_rtx_out = 0;
3960 			bbr->r_ctl.recovery_lr = bbr->r_ctl.rc_pkt_epoch_loss_rate;
3961 			tcp_bbr_tso_size_check(bbr, bbr->r_ctl.rc_rcvtime);
3962 			if (bbr->rc_inp->inp_in_hpts &&
3963 			    ((bbr->r_ctl.rc_hpts_flags & PACE_TMR_RACK) == 0)) {
3964 				/*
3965 				 * When we enter recovery, we need to restart
3966 				 * any timers. This may mean we gain an agg
3967 				 * early, which will be made up for at the last
3968 				 * rxt out.
3969 				 */
3970 				bbr->rc_timer_first = 1;
3971 				bbr_timer_cancel(bbr, __LINE__, bbr->r_ctl.rc_rcvtime);
3972 			}
3973 			/*
3974 			 * Calculate a new cwnd based on to the current
3975 			 * delivery rate with no gain. We get the bdp
3976 			 * without gaining it up like we normally would and
3977 			 * we use the last cur_del_rate.
3978 			 */
3979 			if ((bbr->rc_use_google == 0) &&
3980 			    (bbr->r_ctl.bbr_rttprobe_gain_val ||
3981 			     (bbr->rc_bbr_state != BBR_STATE_PROBE_RTT))) {
3982 				tp->snd_cwnd = ctf_flight_size(tp,
3983 					           (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes)) +
3984 					(tp->t_maxseg - bbr->rc_last_options);
3985 				if (tp->snd_cwnd < get_min_cwnd(bbr)) {
3986 					/* We always gate to min cwnd */
3987 					tp->snd_cwnd = get_min_cwnd(bbr);
3988 				}
3989 				bbr_log_type_cwndupd(bbr, 0, 0, 0, 14, 0, 0, __LINE__);
3990 			}
3991 			bbr_log_type_enter_rec(bbr, rsm->r_start);
3992 		}
3993 		break;
3994 	case CC_RTO_ERR:
3995 		KMOD_TCPSTAT_INC(tcps_sndrexmitbad);
3996 		/* RTO was unnecessary, so reset everything. */
3997 		bbr_reset_lt_bw_sampling(bbr, bbr->r_ctl.rc_rcvtime);
3998 		if (bbr->rc_bbr_state != BBR_STATE_PROBE_RTT) {
3999 			tp->snd_cwnd = tp->snd_cwnd_prev;
4000 			tp->snd_ssthresh = tp->snd_ssthresh_prev;
4001 			tp->snd_recover = tp->snd_recover_prev;
4002 			tp->snd_cwnd = max(tp->snd_cwnd, bbr->r_ctl.rc_cwnd_on_ent);
4003 			bbr_log_type_cwndupd(bbr, 0, 0, 0, 13, 0, 0, __LINE__);
4004 		}
4005 		tp->t_badrxtwin = 0;
4006 		break;
4007 	}
4008 }
4009 
4010 /*
4011  * Indicate whether this ack should be delayed.  We can delay the ack if
4012  * following conditions are met:
4013  *	- There is no delayed ack timer in progress.
4014  *	- Our last ack wasn't a 0-sized window. We never want to delay
4015  *	  the ack that opens up a 0-sized window.
4016  *	- LRO wasn't used for this segment. We make sure by checking that the
4017  *	  segment size is not larger than the MSS.
4018  *	- Delayed acks are enabled or this is a half-synchronized T/TCP
4019  *	  connection.
4020  *	- The data being acked is less than a full segment (a stretch ack
4021  *        of more than a segment we should ack.
4022  *      - nsegs is 1 (if its more than that we received more than 1 ack).
4023  */
4024 #define DELAY_ACK(tp, bbr, nsegs)				\
4025 	(((tp->t_flags & TF_RXWIN0SENT) == 0) &&		\
4026 	 ((tp->t_flags & TF_DELACK) == 0) && 		 	\
4027 	 ((bbr->bbr_segs_rcvd + nsegs) < tp->t_delayed_ack) &&	\
4028 	 (tp->t_delayed_ack || (tp->t_flags & TF_NEEDSYN)))
4029 
4030 /*
4031  * Return the lowest RSM in the map of
4032  * packets still in flight that is not acked.
4033  * This should normally find on the first one
4034  * since we remove packets from the send
4035  * map after they are marked ACKED.
4036  */
4037 static struct bbr_sendmap *
4038 bbr_find_lowest_rsm(struct tcp_bbr *bbr)
4039 {
4040 	struct bbr_sendmap *rsm;
4041 
4042 	/*
4043 	 * Walk the time-order transmitted list looking for an rsm that is
4044 	 * not acked. This will be the one that was sent the longest time
4045 	 * ago that is still outstanding.
4046 	 */
4047 	TAILQ_FOREACH(rsm, &bbr->r_ctl.rc_tmap, r_tnext) {
4048 		if (rsm->r_flags & BBR_ACKED) {
4049 			continue;
4050 		}
4051 		goto finish;
4052 	}
4053 finish:
4054 	return (rsm);
4055 }
4056 
4057 static struct bbr_sendmap *
4058 bbr_find_high_nonack(struct tcp_bbr *bbr, struct bbr_sendmap *rsm)
4059 {
4060 	struct bbr_sendmap *prsm;
4061 
4062 	/*
4063 	 * Walk the sequence order list backward until we hit and arrive at
4064 	 * the highest seq not acked. In theory when this is called it
4065 	 * should be the last segment (which it was not).
4066 	 */
4067 	prsm = rsm;
4068 	TAILQ_FOREACH_REVERSE_FROM(prsm, &bbr->r_ctl.rc_map, bbr_head, r_next) {
4069 		if (prsm->r_flags & (BBR_ACKED | BBR_HAS_FIN)) {
4070 			continue;
4071 		}
4072 		return (prsm);
4073 	}
4074 	return (NULL);
4075 }
4076 
4077 /*
4078  * Returns to the caller the number of microseconds that
4079  * the packet can be outstanding before we think we
4080  * should have had an ack returned.
4081  */
4082 static uint32_t
4083 bbr_calc_thresh_rack(struct tcp_bbr *bbr, uint32_t srtt, uint32_t cts, struct bbr_sendmap *rsm)
4084 {
4085 	/*
4086 	 * lro is the flag we use to determine if we have seen reordering.
4087 	 * If it gets set we have seen reordering. The reorder logic either
4088 	 * works in one of two ways:
4089 	 *
4090 	 * If reorder-fade is configured, then we track the last time we saw
4091 	 * re-ordering occur. If we reach the point where enough time as
4092 	 * passed we no longer consider reordering has occuring.
4093 	 *
4094 	 * Or if reorder-face is 0, then once we see reordering we consider
4095 	 * the connection to alway be subject to reordering and just set lro
4096 	 * to 1.
4097 	 *
4098 	 * In the end if lro is non-zero we add the extra time for
4099 	 * reordering in.
4100 	 */
4101 	int32_t lro;
4102 	uint32_t thresh, t_rxtcur;
4103 
4104 	if (srtt == 0)
4105 		srtt = 1;
4106 	if (bbr->r_ctl.rc_reorder_ts) {
4107 		if (bbr->r_ctl.rc_reorder_fade) {
4108 			if (SEQ_GEQ(cts, bbr->r_ctl.rc_reorder_ts)) {
4109 				lro = cts - bbr->r_ctl.rc_reorder_ts;
4110 				if (lro == 0) {
4111 					/*
4112 					 * No time as passed since the last
4113 					 * reorder, mark it as reordering.
4114 					 */
4115 					lro = 1;
4116 				}
4117 			} else {
4118 				/* Negative time? */
4119 				lro = 0;
4120 			}
4121 			if (lro > bbr->r_ctl.rc_reorder_fade) {
4122 				/* Turn off reordering seen too */
4123 				bbr->r_ctl.rc_reorder_ts = 0;
4124 				lro = 0;
4125 			}
4126 		} else {
4127 			/* Reodering does not fade */
4128 			lro = 1;
4129 		}
4130 	} else {
4131 		lro = 0;
4132 	}
4133 	thresh = srtt + bbr->r_ctl.rc_pkt_delay;
4134 	if (lro) {
4135 		/* It must be set, if not you get 1/4 rtt */
4136 		if (bbr->r_ctl.rc_reorder_shift)
4137 			thresh += (srtt >> bbr->r_ctl.rc_reorder_shift);
4138 		else
4139 			thresh += (srtt >> 2);
4140 	} else {
4141 		thresh += 1000;
4142 	}
4143 	/* We don't let the rack timeout be above a RTO */
4144 	if ((bbr->rc_tp)->t_srtt == 0)
4145 		t_rxtcur = BBR_INITIAL_RTO;
4146 	else
4147 		t_rxtcur = TICKS_2_USEC(bbr->rc_tp->t_rxtcur);
4148 	if (thresh > t_rxtcur) {
4149 		thresh = t_rxtcur;
4150 	}
4151 	/* And we don't want it above the RTO max either */
4152 	if (thresh > (((uint32_t)bbr->rc_max_rto_sec) * USECS_IN_SECOND)) {
4153 		thresh = (((uint32_t)bbr->rc_max_rto_sec) * USECS_IN_SECOND);
4154 	}
4155 	bbr_log_thresh_choice(bbr, cts, thresh, lro, srtt, rsm, BBR_TO_FRM_RACK);
4156 	return (thresh);
4157 }
4158 
4159 /*
4160  * Return to the caller the amount of time in mico-seconds
4161  * that should be used for the TLP timer from the last
4162  * send time of this packet.
4163  */
4164 static uint32_t
4165 bbr_calc_thresh_tlp(struct tcpcb *tp, struct tcp_bbr *bbr,
4166     struct bbr_sendmap *rsm, uint32_t srtt,
4167     uint32_t cts)
4168 {
4169 	uint32_t thresh, len, maxseg, t_rxtcur;
4170 	struct bbr_sendmap *prsm;
4171 
4172 	if (srtt == 0)
4173 		srtt = 1;
4174 	if (bbr->rc_tlp_threshold)
4175 		thresh = srtt + (srtt / bbr->rc_tlp_threshold);
4176 	else
4177 		thresh = (srtt * 2);
4178 	maxseg = tp->t_maxseg - bbr->rc_last_options;
4179 	/* Get the previous sent packet, if any  */
4180 	len = rsm->r_end - rsm->r_start;
4181 
4182 	/* 2.1 behavior */
4183 	prsm = TAILQ_PREV(rsm, bbr_head, r_tnext);
4184 	if (prsm && (len <= maxseg)) {
4185 		/*
4186 		 * Two packets outstanding, thresh should be (2*srtt) +
4187 		 * possible inter-packet delay (if any).
4188 		 */
4189 		uint32_t inter_gap = 0;
4190 		int idx, nidx;
4191 
4192 		idx = rsm->r_rtr_cnt - 1;
4193 		nidx = prsm->r_rtr_cnt - 1;
4194 		if (TSTMP_GEQ(rsm->r_tim_lastsent[nidx], prsm->r_tim_lastsent[idx])) {
4195 			/* Yes it was sent later (or at the same time) */
4196 			inter_gap = rsm->r_tim_lastsent[idx] - prsm->r_tim_lastsent[nidx];
4197 		}
4198 		thresh += inter_gap;
4199 	} else if (len <= maxseg) {
4200 		/*
4201 		 * Possibly compensate for delayed-ack.
4202 		 */
4203 		uint32_t alt_thresh;
4204 
4205 		alt_thresh = srtt + (srtt / 2) + bbr_delayed_ack_time;
4206 		if (alt_thresh > thresh)
4207 			thresh = alt_thresh;
4208 	}
4209 	/* Not above the current  RTO */
4210 	if (tp->t_srtt == 0)
4211 		t_rxtcur = BBR_INITIAL_RTO;
4212 	else
4213 		t_rxtcur = TICKS_2_USEC(tp->t_rxtcur);
4214 
4215 	bbr_log_thresh_choice(bbr, cts, thresh, t_rxtcur, srtt, rsm, BBR_TO_FRM_TLP);
4216 	/* Not above an RTO */
4217 	if (thresh > t_rxtcur) {
4218 		thresh = t_rxtcur;
4219 	}
4220 	/* Not above a RTO max */
4221 	if (thresh > (((uint32_t)bbr->rc_max_rto_sec) * USECS_IN_SECOND)) {
4222 		thresh = (((uint32_t)bbr->rc_max_rto_sec) * USECS_IN_SECOND);
4223 	}
4224 	/* And now apply the user TLP min */
4225 	if (thresh < bbr_tlp_min) {
4226 		thresh = bbr_tlp_min;
4227 	}
4228 	return (thresh);
4229 }
4230 
4231 /*
4232  * Return one of three RTTs to use (in microseconds).
4233  */
4234 static __inline uint32_t
4235 bbr_get_rtt(struct tcp_bbr *bbr, int32_t rtt_type)
4236 {
4237 	uint32_t f_rtt;
4238 	uint32_t srtt;
4239 
4240 	f_rtt = get_filter_value_small(&bbr->r_ctl.rc_rttprop);
4241 	if (get_filter_value_small(&bbr->r_ctl.rc_rttprop) == 0xffffffff) {
4242 		/* We have no rtt at all */
4243 		if (bbr->rc_tp->t_srtt == 0)
4244 			f_rtt = BBR_INITIAL_RTO;
4245 		else
4246 			f_rtt = (TICKS_2_USEC(bbr->rc_tp->t_srtt) >> TCP_RTT_SHIFT);
4247 		/*
4248 		 * Since we don't know how good the rtt is apply a
4249 		 * delayed-ack min
4250 		 */
4251 		if (f_rtt < bbr_delayed_ack_time) {
4252 			f_rtt = bbr_delayed_ack_time;
4253 		}
4254 	}
4255 	/* Take the filter version or last measured pkt-rtt */
4256 	if (rtt_type == BBR_RTT_PROP) {
4257 		srtt = f_rtt;
4258 	} else if (rtt_type == BBR_RTT_PKTRTT) {
4259 		if (bbr->r_ctl.rc_pkt_epoch_rtt) {
4260 			srtt = bbr->r_ctl.rc_pkt_epoch_rtt;
4261 		} else {
4262 			/* No pkt rtt yet */
4263 			srtt = f_rtt;
4264 		}
4265 	} else if (rtt_type == BBR_RTT_RACK) {
4266 		srtt = bbr->r_ctl.rc_last_rtt;
4267 		/* We need to add in any internal delay for our timer */
4268 		if (bbr->rc_ack_was_delayed)
4269 			srtt += bbr->r_ctl.rc_ack_hdwr_delay;
4270 	} else if (rtt_type == BBR_SRTT) {
4271 		srtt = (TICKS_2_USEC(bbr->rc_tp->t_srtt) >> TCP_RTT_SHIFT);
4272 	} else {
4273 		/* TSNH */
4274 		srtt = f_rtt;
4275 #ifdef BBR_INVARIANTS
4276 		panic("Unknown rtt request type %d", rtt_type);
4277 #endif
4278 	}
4279 	return (srtt);
4280 }
4281 
4282 static int
4283 bbr_is_lost(struct tcp_bbr *bbr, struct bbr_sendmap *rsm, uint32_t cts)
4284 {
4285 	uint32_t thresh;
4286 
4287 	thresh = bbr_calc_thresh_rack(bbr, bbr_get_rtt(bbr, BBR_RTT_RACK),
4288 				      cts, rsm);
4289 	if ((cts - rsm->r_tim_lastsent[(rsm->r_rtr_cnt - 1)]) >= thresh) {
4290 		/* It is lost (past time) */
4291 		return (1);
4292 	}
4293 	return (0);
4294 }
4295 
4296 /*
4297  * Return a sendmap if we need to retransmit something.
4298  */
4299 static struct bbr_sendmap *
4300 bbr_check_recovery_mode(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4301 {
4302 	/*
4303 	 * Check to see that we don't need to fall into recovery. We will
4304 	 * need to do so if our oldest transmit is past the time we should
4305 	 * have had an ack.
4306 	 */
4307 
4308 	struct bbr_sendmap *rsm;
4309 	int32_t idx;
4310 
4311 	if (TAILQ_EMPTY(&bbr->r_ctl.rc_map)) {
4312 		/* Nothing outstanding that we know of */
4313 		return (NULL);
4314 	}
4315 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_tmap);
4316 	if (rsm == NULL) {
4317 		/* Nothing in the transmit map */
4318 		return (NULL);
4319 	}
4320 	if (tp->t_flags & TF_SENTFIN) {
4321 		/* Fin restricted, don't find anything once a fin is sent */
4322 		return (NULL);
4323 	}
4324 	if (rsm->r_flags & BBR_ACKED) {
4325 		/*
4326 		 * Ok the first one is acked (this really should not happen
4327 		 * since we remove the from the tmap once they are acked)
4328 		 */
4329 		rsm = bbr_find_lowest_rsm(bbr);
4330 		if (rsm == NULL)
4331 			return (NULL);
4332 	}
4333 	idx = rsm->r_rtr_cnt - 1;
4334 	if (SEQ_LEQ(cts, rsm->r_tim_lastsent[idx])) {
4335 		/* Send timestamp is the same or less? can't be ready */
4336 		return (NULL);
4337 	}
4338 	/* Get our RTT time */
4339 	if (bbr_is_lost(bbr, rsm, cts) &&
4340 	    ((rsm->r_dupack >= DUP_ACK_THRESHOLD) ||
4341 	     (rsm->r_flags & BBR_SACK_PASSED))) {
4342 		if ((rsm->r_flags & BBR_MARKED_LOST) == 0) {
4343 			rsm->r_flags |= BBR_MARKED_LOST;
4344 			bbr->r_ctl.rc_lost += rsm->r_end - rsm->r_start;
4345 			bbr->r_ctl.rc_lost_bytes += rsm->r_end - rsm->r_start;
4346 		}
4347 		bbr_cong_signal(tp, NULL, CC_NDUPACK, rsm);
4348 #ifdef BBR_INVARIANTS
4349 		if ((rsm->r_end - rsm->r_start) == 0)
4350 			panic("tp:%p bbr:%p rsm:%p length is 0?", tp, bbr, rsm);
4351 #endif
4352 		return (rsm);
4353 	}
4354 	return (NULL);
4355 }
4356 
4357 /*
4358  * RACK Timer, here we simply do logging and house keeping.
4359  * the normal bbr_output_wtime() function will call the
4360  * appropriate thing to check if we need to do a RACK retransmit.
4361  * We return 1, saying don't proceed with bbr_output_wtime only
4362  * when all timers have been stopped (destroyed PCB?).
4363  */
4364 static int
4365 bbr_timeout_rack(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4366 {
4367 	/*
4368 	 * This timer simply provides an internal trigger to send out data.
4369 	 * The check_recovery_mode call will see if there are needed
4370 	 * retransmissions, if so we will enter fast-recovery. The output
4371 	 * call may or may not do the same thing depending on sysctl
4372 	 * settings.
4373 	 */
4374 	uint32_t lost;
4375 
4376 	if (bbr->rc_all_timers_stopped) {
4377 		return (1);
4378 	}
4379 	if (TSTMP_LT(cts, bbr->r_ctl.rc_timer_exp)) {
4380 		/* Its not time yet */
4381 		return (0);
4382 	}
4383 	BBR_STAT_INC(bbr_to_tot);
4384 	lost = bbr->r_ctl.rc_lost;
4385 	if (bbr->r_state && (bbr->r_state != tp->t_state))
4386 		bbr_set_state(tp, bbr, 0);
4387 	bbr_log_to_event(bbr, cts, BBR_TO_FRM_RACK);
4388 	if (bbr->r_ctl.rc_resend == NULL) {
4389 		/* Lets do the check here */
4390 		bbr->r_ctl.rc_resend = bbr_check_recovery_mode(tp, bbr, cts);
4391 	}
4392 	if (bbr_policer_call_from_rack_to)
4393 		bbr_lt_bw_sampling(bbr, cts, (bbr->r_ctl.rc_lost > lost));
4394 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_RACK;
4395 	return (0);
4396 }
4397 
4398 static __inline void
4399 bbr_clone_rsm(struct tcp_bbr *bbr, struct bbr_sendmap *nrsm, struct bbr_sendmap *rsm, uint32_t start)
4400 {
4401 	int idx;
4402 
4403 	nrsm->r_start = start;
4404 	nrsm->r_end = rsm->r_end;
4405 	nrsm->r_rtr_cnt = rsm->r_rtr_cnt;
4406 	nrsm->r_flags = rsm->r_flags;
4407 	/* We don't transfer forward the SYN flag */
4408 	nrsm->r_flags &= ~BBR_HAS_SYN;
4409 	/* We move forward the FIN flag, not that this should happen */
4410 	rsm->r_flags &= ~BBR_HAS_FIN;
4411 	nrsm->r_dupack = rsm->r_dupack;
4412 	nrsm->r_rtr_bytes = 0;
4413 	nrsm->r_is_gain = rsm->r_is_gain;
4414 	nrsm->r_is_drain = rsm->r_is_drain;
4415 	nrsm->r_delivered = rsm->r_delivered;
4416 	nrsm->r_ts_valid = rsm->r_ts_valid;
4417 	nrsm->r_del_ack_ts = rsm->r_del_ack_ts;
4418 	nrsm->r_del_time = rsm->r_del_time;
4419 	nrsm->r_app_limited = rsm->r_app_limited;
4420 	nrsm->r_first_sent_time = rsm->r_first_sent_time;
4421 	nrsm->r_flight_at_send = rsm->r_flight_at_send;
4422 	/* We split a piece the lower section looses any just_ret flag. */
4423 	nrsm->r_bbr_state = rsm->r_bbr_state;
4424 	for (idx = 0; idx < nrsm->r_rtr_cnt; idx++) {
4425 		nrsm->r_tim_lastsent[idx] = rsm->r_tim_lastsent[idx];
4426 	}
4427 	rsm->r_end = nrsm->r_start;
4428 	idx = min((bbr->rc_tp->t_maxseg - bbr->rc_last_options), bbr->r_ctl.rc_pace_max_segs);
4429 	idx /= 8;
4430 	/* Check if we got too small */
4431 	if ((rsm->r_is_smallmap == 0) &&
4432 	    ((rsm->r_end - rsm->r_start) <= idx)) {
4433 		bbr->r_ctl.rc_num_small_maps_alloced++;
4434 		rsm->r_is_smallmap = 1;
4435 	}
4436 	/* Check the new one as well */
4437 	if ((nrsm->r_end - nrsm->r_start) <= idx) {
4438 		bbr->r_ctl.rc_num_small_maps_alloced++;
4439 		nrsm->r_is_smallmap = 1;
4440 	}
4441 }
4442 
4443 static int
4444 bbr_sack_mergable(struct bbr_sendmap *at,
4445 		  uint32_t start, uint32_t end)
4446 {
4447 	/*
4448 	 * Given a sack block defined by
4449 	 * start and end, and a current postion
4450 	 * at. Return 1 if either side of at
4451 	 * would show that the block is mergable
4452 	 * to that side. A block to be mergable
4453 	 * must have overlap with the start/end
4454 	 * and be in the SACK'd state.
4455 	 */
4456 	struct bbr_sendmap *l_rsm;
4457 	struct bbr_sendmap *r_rsm;
4458 
4459 	/* first get the either side blocks */
4460 	l_rsm = TAILQ_PREV(at, bbr_head, r_next);
4461 	r_rsm = TAILQ_NEXT(at, r_next);
4462 	if (l_rsm && (l_rsm->r_flags & BBR_ACKED)) {
4463 		/* Potentially mergeable */
4464 		if ((l_rsm->r_end == start) ||
4465 		    (SEQ_LT(start, l_rsm->r_end) &&
4466 		     SEQ_GT(end, l_rsm->r_end))) {
4467 			    /*
4468 			     * map blk   |------|
4469 			     * sack blk         |------|
4470 			     * <or>
4471 			     * map blk   |------|
4472 			     * sack blk      |------|
4473 			     */
4474 			    return (1);
4475 		    }
4476 	}
4477 	if (r_rsm && (r_rsm->r_flags & BBR_ACKED)) {
4478 		/* Potentially mergeable */
4479 		if ((r_rsm->r_start == end) ||
4480 		    (SEQ_LT(start, r_rsm->r_start) &&
4481 		     SEQ_GT(end, r_rsm->r_start))) {
4482 			/*
4483 			 * map blk          |---------|
4484 			 * sack blk    |----|
4485 			 * <or>
4486 			 * map blk          |---------|
4487 			 * sack blk    |-------|
4488 			 */
4489 			return (1);
4490 		}
4491 	}
4492 	return (0);
4493 }
4494 
4495 static struct bbr_sendmap *
4496 bbr_merge_rsm(struct tcp_bbr *bbr,
4497 	      struct bbr_sendmap *l_rsm,
4498 	      struct bbr_sendmap *r_rsm)
4499 {
4500 	/*
4501 	 * We are merging two ack'd RSM's,
4502 	 * the l_rsm is on the left (lower seq
4503 	 * values) and the r_rsm is on the right
4504 	 * (higher seq value). The simplest way
4505 	 * to merge these is to move the right
4506 	 * one into the left. I don't think there
4507 	 * is any reason we need to try to find
4508 	 * the oldest (or last oldest retransmitted).
4509 	 */
4510 	l_rsm->r_end = r_rsm->r_end;
4511 	if (l_rsm->r_dupack < r_rsm->r_dupack)
4512 		l_rsm->r_dupack = r_rsm->r_dupack;
4513 	if (r_rsm->r_rtr_bytes)
4514 		l_rsm->r_rtr_bytes += r_rsm->r_rtr_bytes;
4515 	if (r_rsm->r_in_tmap) {
4516 		/* This really should not happen */
4517 		TAILQ_REMOVE(&bbr->r_ctl.rc_tmap, r_rsm, r_tnext);
4518 	}
4519 	if (r_rsm->r_app_limited)
4520 		l_rsm->r_app_limited = r_rsm->r_app_limited;
4521 	/* Now the flags */
4522 	if (r_rsm->r_flags & BBR_HAS_FIN)
4523 		l_rsm->r_flags |= BBR_HAS_FIN;
4524 	if (r_rsm->r_flags & BBR_TLP)
4525 		l_rsm->r_flags |= BBR_TLP;
4526 	if (r_rsm->r_flags & BBR_RWND_COLLAPSED)
4527 		l_rsm->r_flags |= BBR_RWND_COLLAPSED;
4528 	if (r_rsm->r_flags & BBR_MARKED_LOST) {
4529 		/* This really should not happen */
4530 		bbr->r_ctl.rc_lost_bytes -= r_rsm->r_end - r_rsm->r_start;
4531 	}
4532 	TAILQ_REMOVE(&bbr->r_ctl.rc_map, r_rsm, r_next);
4533 	if ((r_rsm->r_limit_type == 0) && (l_rsm->r_limit_type != 0)) {
4534 		/* Transfer the split limit to the map we free */
4535 		r_rsm->r_limit_type = l_rsm->r_limit_type;
4536 		l_rsm->r_limit_type = 0;
4537 	}
4538 	bbr_free(bbr, r_rsm);
4539 	return(l_rsm);
4540 }
4541 
4542 /*
4543  * TLP Timer, here we simply setup what segment we want to
4544  * have the TLP expire on, the normal bbr_output_wtime() will then
4545  * send it out.
4546  *
4547  * We return 1, saying don't proceed with bbr_output_wtime only
4548  * when all timers have been stopped (destroyed PCB?).
4549  */
4550 static int
4551 bbr_timeout_tlp(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4552 {
4553 	/*
4554 	 * Tail Loss Probe.
4555 	 */
4556 	struct bbr_sendmap *rsm = NULL;
4557 	struct socket *so;
4558 	uint32_t amm;
4559 	uint32_t out, avail;
4560 	uint32_t maxseg;
4561 	int collapsed_win = 0;
4562 
4563 	if (bbr->rc_all_timers_stopped) {
4564 		return (1);
4565 	}
4566 	if (TSTMP_LT(cts, bbr->r_ctl.rc_timer_exp)) {
4567 		/* Its not time yet */
4568 		return (0);
4569 	}
4570 	if (ctf_progress_timeout_check(tp, true)) {
4571 		bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP, __LINE__);
4572 		tcp_set_inp_to_drop(bbr->rc_inp, ETIMEDOUT);
4573 		return (1);
4574 	}
4575 	/* Did we somehow get into persists? */
4576 	if (bbr->rc_in_persist) {
4577 		return (0);
4578 	}
4579 	if (bbr->r_state && (bbr->r_state != tp->t_state))
4580 		bbr_set_state(tp, bbr, 0);
4581 	BBR_STAT_INC(bbr_tlp_tot);
4582 	maxseg = tp->t_maxseg - bbr->rc_last_options;
4583 	/*
4584 	 * A TLP timer has expired. We have been idle for 2 rtts. So we now
4585 	 * need to figure out how to force a full MSS segment out.
4586 	 */
4587 	so = tp->t_inpcb->inp_socket;
4588 	avail = sbavail(&so->so_snd);
4589 	out = ctf_outstanding(tp);
4590 	if (out > tp->snd_wnd) {
4591 		/* special case, we need a retransmission */
4592 		collapsed_win = 1;
4593 		goto need_retran;
4594 	}
4595 	if (avail > out) {
4596 		/* New data is available */
4597 		amm = avail - out;
4598 		if (amm > maxseg) {
4599 			amm = maxseg;
4600 		} else if ((amm < maxseg) && ((tp->t_flags & TF_NODELAY) == 0)) {
4601 			/* not enough to fill a MTU and no-delay is off */
4602 			goto need_retran;
4603 		}
4604 		/* Set the send-new override */
4605 		if ((out + amm) <= tp->snd_wnd) {
4606 			bbr->rc_tlp_new_data = 1;
4607 		} else {
4608 			goto need_retran;
4609 		}
4610 		bbr->r_ctl.rc_tlp_seg_send_cnt = 0;
4611 		bbr->r_ctl.rc_last_tlp_seq = tp->snd_max;
4612 		bbr->r_ctl.rc_tlp_send = NULL;
4613 		/* cap any slots */
4614 		BBR_STAT_INC(bbr_tlp_newdata);
4615 		goto send;
4616 	}
4617 need_retran:
4618 	/*
4619 	 * Ok we need to arrange the last un-acked segment to be re-sent, or
4620 	 * optionally the first un-acked segment.
4621 	 */
4622 	if (collapsed_win == 0) {
4623 		rsm = TAILQ_LAST_FAST(&bbr->r_ctl.rc_map, bbr_sendmap, r_next);
4624 		if (rsm && (BBR_ACKED | BBR_HAS_FIN)) {
4625 			rsm = bbr_find_high_nonack(bbr, rsm);
4626 		}
4627 		if (rsm == NULL) {
4628 			goto restore;
4629 		}
4630 	} else {
4631 		/*
4632 		 * We must find the last segment
4633 		 * that was acceptable by the client.
4634 		 */
4635 		TAILQ_FOREACH_REVERSE(rsm, &bbr->r_ctl.rc_map, bbr_head, r_next) {
4636 			if ((rsm->r_flags & BBR_RWND_COLLAPSED) == 0) {
4637 				/* Found one */
4638 				break;
4639 			}
4640 		}
4641 		if (rsm == NULL) {
4642 			/* None? if so send the first */
4643 			rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
4644 			if (rsm == NULL)
4645 				goto restore;
4646 		}
4647 	}
4648 	if ((rsm->r_end - rsm->r_start) > maxseg) {
4649 		/*
4650 		 * We need to split this the last segment in two.
4651 		 */
4652 		struct bbr_sendmap *nrsm;
4653 
4654 		nrsm = bbr_alloc_full_limit(bbr);
4655 		if (nrsm == NULL) {
4656 			/*
4657 			 * We can't get memory to split, we can either just
4658 			 * not split it. Or retransmit the whole piece, lets
4659 			 * do the large send (BTLP :-) ).
4660 			 */
4661 			goto go_for_it;
4662 		}
4663 		bbr_clone_rsm(bbr, nrsm, rsm, (rsm->r_end - maxseg));
4664 		TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_map, rsm, nrsm, r_next);
4665 		if (rsm->r_in_tmap) {
4666 			TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
4667 			nrsm->r_in_tmap = 1;
4668 		}
4669 		rsm->r_flags &= (~BBR_HAS_FIN);
4670 		rsm = nrsm;
4671 	}
4672 go_for_it:
4673 	bbr->r_ctl.rc_tlp_send = rsm;
4674 	bbr->rc_tlp_rtx_out = 1;
4675 	if (rsm->r_start == bbr->r_ctl.rc_last_tlp_seq) {
4676 		bbr->r_ctl.rc_tlp_seg_send_cnt++;
4677 		tp->t_rxtshift++;
4678 	} else {
4679 		bbr->r_ctl.rc_last_tlp_seq = rsm->r_start;
4680 		bbr->r_ctl.rc_tlp_seg_send_cnt = 1;
4681 	}
4682 send:
4683 	if (bbr->r_ctl.rc_tlp_seg_send_cnt > bbr_tlp_max_resend) {
4684 		/*
4685 		 * Can't [re]/transmit a segment we have retranmitted the
4686 		 * max times. We need the retransmit timer to take over.
4687 		 */
4688 restore:
4689 		bbr->rc_tlp_new_data = 0;
4690 		bbr->r_ctl.rc_tlp_send = NULL;
4691 		if (rsm)
4692 			rsm->r_flags &= ~BBR_TLP;
4693 		BBR_STAT_INC(bbr_tlp_retran_fail);
4694 		return (0);
4695 	} else if (rsm) {
4696 		rsm->r_flags |= BBR_TLP;
4697 	}
4698 	if (rsm && (rsm->r_start == bbr->r_ctl.rc_last_tlp_seq) &&
4699 	    (bbr->r_ctl.rc_tlp_seg_send_cnt > bbr_tlp_max_resend)) {
4700 		/*
4701 		 * We have retransmitted to many times for TLP. Switch to
4702 		 * the regular RTO timer
4703 		 */
4704 		goto restore;
4705 	}
4706 	bbr_log_to_event(bbr, cts, BBR_TO_FRM_TLP);
4707 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_TLP;
4708 	return (0);
4709 }
4710 
4711 /*
4712  * Delayed ack Timer, here we simply need to setup the
4713  * ACK_NOW flag and remove the DELACK flag. From there
4714  * the output routine will send the ack out.
4715  *
4716  * We only return 1, saying don't proceed, if all timers
4717  * are stopped (destroyed PCB?).
4718  */
4719 static int
4720 bbr_timeout_delack(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4721 {
4722 	if (bbr->rc_all_timers_stopped) {
4723 		return (1);
4724 	}
4725 	bbr_log_to_event(bbr, cts, BBR_TO_FRM_DELACK);
4726 	tp->t_flags &= ~TF_DELACK;
4727 	tp->t_flags |= TF_ACKNOW;
4728 	KMOD_TCPSTAT_INC(tcps_delack);
4729 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_DELACK;
4730 	return (0);
4731 }
4732 
4733 /*
4734  * Here we send a KEEP-ALIVE like probe to the
4735  * peer, we do not send data.
4736  *
4737  * We only return 1, saying don't proceed, if all timers
4738  * are stopped (destroyed PCB?).
4739  */
4740 static int
4741 bbr_timeout_persist(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4742 {
4743 	struct tcptemp *t_template;
4744 	int32_t retval = 1;
4745 
4746 	if (bbr->rc_all_timers_stopped) {
4747 		return (1);
4748 	}
4749 	if (bbr->rc_in_persist == 0)
4750 		return (0);
4751 	KASSERT(tp->t_inpcb != NULL,
4752 	    ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
4753 	/*
4754 	 * Persistence timer into zero window. Force a byte to be output, if
4755 	 * possible.
4756 	 */
4757 	bbr_log_to_event(bbr, cts, BBR_TO_FRM_PERSIST);
4758 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_PERSIT;
4759 	KMOD_TCPSTAT_INC(tcps_persisttimeo);
4760 	/*
4761 	 * Have we exceeded the user specified progress time?
4762 	 */
4763 	if (ctf_progress_timeout_check(tp, true)) {
4764 		bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP, __LINE__);
4765 		tcp_set_inp_to_drop(bbr->rc_inp, ETIMEDOUT);
4766 		goto out;
4767 	}
4768 	/*
4769 	 * Hack: if the peer is dead/unreachable, we do not time out if the
4770 	 * window is closed.  After a full backoff, drop the connection if
4771 	 * the idle time (no responses to probes) reaches the maximum
4772 	 * backoff that we would use if retransmitting.
4773 	 */
4774 	if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
4775 	    (ticks - tp->t_rcvtime >= tcp_maxpersistidle ||
4776 	    ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) {
4777 		KMOD_TCPSTAT_INC(tcps_persistdrop);
4778 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
4779 		tcp_set_inp_to_drop(bbr->rc_inp, ETIMEDOUT);
4780 		goto out;
4781 	}
4782 	if ((sbavail(&bbr->rc_inp->inp_socket->so_snd) == 0) &&
4783 	    tp->snd_una == tp->snd_max) {
4784 		bbr_exit_persist(tp, bbr, cts, __LINE__);
4785 		retval = 0;
4786 		goto out;
4787 	}
4788 	/*
4789 	 * If the user has closed the socket then drop a persisting
4790 	 * connection after a much reduced timeout.
4791 	 */
4792 	if (tp->t_state > TCPS_CLOSE_WAIT &&
4793 	    (ticks - tp->t_rcvtime) >= TCPTV_PERSMAX) {
4794 		KMOD_TCPSTAT_INC(tcps_persistdrop);
4795 		tcp_log_end_status(tp, TCP_EI_STATUS_PERSIST_MAX);
4796 		tcp_set_inp_to_drop(bbr->rc_inp, ETIMEDOUT);
4797 		goto out;
4798 	}
4799 	t_template = tcpip_maketemplate(bbr->rc_inp);
4800 	if (t_template) {
4801 		tcp_respond(tp, t_template->tt_ipgen,
4802 			    &t_template->tt_t, (struct mbuf *)NULL,
4803 			    tp->rcv_nxt, tp->snd_una - 1, 0);
4804 		/* This sends an ack */
4805 		if (tp->t_flags & TF_DELACK)
4806 			tp->t_flags &= ~TF_DELACK;
4807 		free(t_template, M_TEMP);
4808 	}
4809 	if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
4810 		tp->t_rxtshift++;
4811 	bbr_start_hpts_timer(bbr, tp, cts, 3, 0, 0);
4812 out:
4813 	return (retval);
4814 }
4815 
4816 /*
4817  * If a keepalive goes off, we had no other timers
4818  * happening. We always return 1 here since this
4819  * routine either drops the connection or sends
4820  * out a segment with respond.
4821  */
4822 static int
4823 bbr_timeout_keepalive(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4824 {
4825 	struct tcptemp *t_template;
4826 	struct inpcb *inp;
4827 
4828 	if (bbr->rc_all_timers_stopped) {
4829 		return (1);
4830 	}
4831 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_KEEP;
4832 	inp = tp->t_inpcb;
4833 	bbr_log_to_event(bbr, cts, BBR_TO_FRM_KEEP);
4834 	/*
4835 	 * Keep-alive timer went off; send something or drop connection if
4836 	 * idle for too long.
4837 	 */
4838 	KMOD_TCPSTAT_INC(tcps_keeptimeo);
4839 	if (tp->t_state < TCPS_ESTABLISHED)
4840 		goto dropit;
4841 	if ((V_tcp_always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
4842 	    tp->t_state <= TCPS_CLOSING) {
4843 		if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp))
4844 			goto dropit;
4845 		/*
4846 		 * Send a packet designed to force a response if the peer is
4847 		 * up and reachable: either an ACK if the connection is
4848 		 * still alive, or an RST if the peer has closed the
4849 		 * connection due to timeout or reboot. Using sequence
4850 		 * number tp->snd_una-1 causes the transmitted zero-length
4851 		 * segment to lie outside the receive window; by the
4852 		 * protocol spec, this requires the correspondent TCP to
4853 		 * respond.
4854 		 */
4855 		KMOD_TCPSTAT_INC(tcps_keepprobe);
4856 		t_template = tcpip_maketemplate(inp);
4857 		if (t_template) {
4858 			tcp_respond(tp, t_template->tt_ipgen,
4859 			    &t_template->tt_t, (struct mbuf *)NULL,
4860 			    tp->rcv_nxt, tp->snd_una - 1, 0);
4861 			free(t_template, M_TEMP);
4862 		}
4863 	}
4864 	bbr_start_hpts_timer(bbr, tp, cts, 4, 0, 0);
4865 	return (1);
4866 dropit:
4867 	KMOD_TCPSTAT_INC(tcps_keepdrops);
4868 	tcp_log_end_status(tp, TCP_EI_STATUS_KEEP_MAX);
4869 	tcp_set_inp_to_drop(bbr->rc_inp, ETIMEDOUT);
4870 	return (1);
4871 }
4872 
4873 /*
4874  * Retransmit helper function, clear up all the ack
4875  * flags and take care of important book keeping.
4876  */
4877 static void
4878 bbr_remxt_tmr(struct tcpcb *tp)
4879 {
4880 	/*
4881 	 * The retransmit timer went off, all sack'd blocks must be
4882 	 * un-acked.
4883 	 */
4884 	struct bbr_sendmap *rsm, *trsm = NULL;
4885 	struct tcp_bbr *bbr;
4886 	uint32_t cts, lost;
4887 
4888 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
4889 	cts = tcp_get_usecs(&bbr->rc_tv);
4890 	lost = bbr->r_ctl.rc_lost;
4891 	if (bbr->r_state && (bbr->r_state != tp->t_state))
4892 		bbr_set_state(tp, bbr, 0);
4893 
4894 	TAILQ_FOREACH(rsm, &bbr->r_ctl.rc_map, r_next) {
4895 		if (rsm->r_flags & BBR_ACKED) {
4896 			uint32_t old_flags;
4897 
4898 			rsm->r_dupack = 0;
4899 			if (rsm->r_in_tmap == 0) {
4900 				/* We must re-add it back to the tlist */
4901 				if (trsm == NULL) {
4902 					TAILQ_INSERT_HEAD(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
4903 				} else {
4904 					TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, trsm, rsm, r_tnext);
4905 				}
4906 				rsm->r_in_tmap = 1;
4907 			}
4908 			old_flags = rsm->r_flags;
4909 			rsm->r_flags |= BBR_RXT_CLEARED;
4910 			rsm->r_flags &= ~(BBR_ACKED | BBR_SACK_PASSED | BBR_WAS_SACKPASS);
4911 			bbr_log_type_rsmclear(bbr, cts, rsm, old_flags, __LINE__);
4912 		} else {
4913 			if ((tp->t_state < TCPS_ESTABLISHED) &&
4914 			    (rsm->r_start == tp->snd_una)) {
4915 				/*
4916 				 * Special case for TCP FO. Where
4917 				 * we sent more data beyond the snd_max.
4918 				 * We don't mark that as lost and stop here.
4919 				 */
4920 				break;
4921 			}
4922 			if ((rsm->r_flags & BBR_MARKED_LOST) == 0) {
4923 				bbr->r_ctl.rc_lost += rsm->r_end - rsm->r_start;
4924 				bbr->r_ctl.rc_lost_bytes += rsm->r_end - rsm->r_start;
4925 			}
4926 			if (bbr_marks_rxt_sack_passed) {
4927 				/*
4928 				 * With this option, we will rack out
4929 				 * in 1ms increments the rest of the packets.
4930 				 */
4931 				rsm->r_flags |= BBR_SACK_PASSED | BBR_MARKED_LOST;
4932 				rsm->r_flags &= ~BBR_WAS_SACKPASS;
4933 			} else {
4934 				/*
4935 				 * With this option we only mark them lost
4936 				 * and remove all sack'd markings. We will run
4937 				 * another RXT or a TLP. This will cause
4938 				 * us to eventually send more based on what
4939 				 * ack's come in.
4940 				 */
4941 				rsm->r_flags |= BBR_MARKED_LOST;
4942 				rsm->r_flags &= ~BBR_WAS_SACKPASS;
4943 				rsm->r_flags &= ~BBR_SACK_PASSED;
4944 			}
4945 		}
4946 		trsm = rsm;
4947 	}
4948 	bbr->r_ctl.rc_resend = TAILQ_FIRST(&bbr->r_ctl.rc_map);
4949 	/* Clear the count (we just un-acked them) */
4950 	bbr_log_to_event(bbr, cts, BBR_TO_FRM_TMR);
4951 	bbr->rc_tlp_new_data = 0;
4952 	bbr->r_ctl.rc_tlp_seg_send_cnt = 0;
4953 	/* zap the behindness on a rxt */
4954 	bbr->r_ctl.rc_hptsi_agg_delay = 0;
4955 	bbr->r_agg_early_set = 0;
4956 	bbr->r_ctl.rc_agg_early = 0;
4957 	bbr->rc_tlp_rtx_out = 0;
4958 	bbr->r_ctl.rc_sacked = 0;
4959 	bbr->r_ctl.rc_sacklast = NULL;
4960 	bbr->r_timer_override = 1;
4961 	bbr_lt_bw_sampling(bbr, cts, (bbr->r_ctl.rc_lost > lost));
4962 }
4963 
4964 /*
4965  * Re-transmit timeout! If we drop the PCB we will return 1, otherwise
4966  * we will setup to retransmit the lowest seq number outstanding.
4967  */
4968 static int
4969 bbr_timeout_rxt(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
4970 {
4971 	int32_t rexmt;
4972 	int32_t retval = 0;
4973 	bool isipv6;
4974 
4975 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_RXT;
4976 	if (bbr->rc_all_timers_stopped) {
4977 		return (1);
4978 	}
4979 	if (TCPS_HAVEESTABLISHED(tp->t_state) &&
4980 	    (tp->snd_una == tp->snd_max)) {
4981 		/* Nothing outstanding .. nothing to do */
4982 		return (0);
4983 	}
4984 	/*
4985 	 * Retransmission timer went off.  Message has not been acked within
4986 	 * retransmit interval.  Back off to a longer retransmit interval
4987 	 * and retransmit one segment.
4988 	 */
4989 	if (ctf_progress_timeout_check(tp, true)) {
4990 		retval = 1;
4991 		bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP, __LINE__);
4992 		tcp_set_inp_to_drop(bbr->rc_inp, ETIMEDOUT);
4993 		goto out;
4994 	}
4995 	bbr_remxt_tmr(tp);
4996 	if ((bbr->r_ctl.rc_resend == NULL) ||
4997 	    ((bbr->r_ctl.rc_resend->r_flags & BBR_RWND_COLLAPSED) == 0)) {
4998 		/*
4999 		 * If the rwnd collapsed on
5000 		 * the one we are retransmitting
5001 		 * it does not count against the
5002 		 * rxt count.
5003 		 */
5004 		tp->t_rxtshift++;
5005 	}
5006 	if (tp->t_rxtshift > TCP_MAXRXTSHIFT) {
5007 		tp->t_rxtshift = TCP_MAXRXTSHIFT;
5008 		KMOD_TCPSTAT_INC(tcps_timeoutdrop);
5009 		retval = 1;
5010 		tcp_log_end_status(tp, TCP_EI_STATUS_RETRAN);
5011 		tcp_set_inp_to_drop(bbr->rc_inp,
5012 		    (tp->t_softerror ? (uint16_t) tp->t_softerror : ETIMEDOUT));
5013 		goto out;
5014 	}
5015 	if (tp->t_state == TCPS_SYN_SENT) {
5016 		/*
5017 		 * If the SYN was retransmitted, indicate CWND to be limited
5018 		 * to 1 segment in cc_conn_init().
5019 		 */
5020 		tp->snd_cwnd = 1;
5021 	} else if (tp->t_rxtshift == 1) {
5022 		/*
5023 		 * first retransmit; record ssthresh and cwnd so they can be
5024 		 * recovered if this turns out to be a "bad" retransmit. A
5025 		 * retransmit is considered "bad" if an ACK for this segment
5026 		 * is received within RTT/2 interval; the assumption here is
5027 		 * that the ACK was already in flight.  See "On Estimating
5028 		 * End-to-End Network Path Properties" by Allman and Paxson
5029 		 * for more details.
5030 		 */
5031 		tp->snd_cwnd = tp->t_maxseg - bbr->rc_last_options;
5032 		if (!IN_RECOVERY(tp->t_flags)) {
5033 			tp->snd_cwnd_prev = tp->snd_cwnd;
5034 			tp->snd_ssthresh_prev = tp->snd_ssthresh;
5035 			tp->snd_recover_prev = tp->snd_recover;
5036 			tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1));
5037 			tp->t_flags |= TF_PREVVALID;
5038 		} else {
5039 			tp->t_flags &= ~TF_PREVVALID;
5040 		}
5041 		tp->snd_cwnd = tp->t_maxseg - bbr->rc_last_options;
5042 	} else {
5043 		tp->snd_cwnd = tp->t_maxseg - bbr->rc_last_options;
5044 		tp->t_flags &= ~TF_PREVVALID;
5045 	}
5046 	KMOD_TCPSTAT_INC(tcps_rexmttimeo);
5047 	if ((tp->t_state == TCPS_SYN_SENT) ||
5048 	    (tp->t_state == TCPS_SYN_RECEIVED))
5049 		rexmt = USEC_2_TICKS(BBR_INITIAL_RTO) * tcp_backoff[tp->t_rxtshift];
5050 	else
5051 		rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
5052 	TCPT_RANGESET(tp->t_rxtcur, rexmt,
5053 	    MSEC_2_TICKS(bbr->r_ctl.rc_min_rto_ms),
5054 	    MSEC_2_TICKS(((uint32_t)bbr->rc_max_rto_sec) * 1000));
5055 	/*
5056 	 * We enter the path for PLMTUD if connection is established or, if
5057 	 * connection is FIN_WAIT_1 status, reason for the last is that if
5058 	 * amount of data we send is very small, we could send it in couple
5059 	 * of packets and process straight to FIN. In that case we won't
5060 	 * catch ESTABLISHED state.
5061 	 */
5062 #ifdef INET6
5063 	isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) ? true : false;
5064 #else
5065 	isipv6 = false;
5066 #endif
5067 	if (((V_tcp_pmtud_blackhole_detect == 1) ||
5068 	    (V_tcp_pmtud_blackhole_detect == 2 && !isipv6) ||
5069 	    (V_tcp_pmtud_blackhole_detect == 3 && isipv6)) &&
5070 	    ((tp->t_state == TCPS_ESTABLISHED) ||
5071 	    (tp->t_state == TCPS_FIN_WAIT_1))) {
5072 		/*
5073 		 * Idea here is that at each stage of mtu probe (usually,
5074 		 * 1448 -> 1188 -> 524) should be given 2 chances to recover
5075 		 * before further clamping down. 'tp->t_rxtshift % 2 == 0'
5076 		 * should take care of that.
5077 		 */
5078 		if (((tp->t_flags2 & (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) ==
5079 		    (TF2_PLPMTU_PMTUD | TF2_PLPMTU_MAXSEGSNT)) &&
5080 		    (tp->t_rxtshift >= 2 && tp->t_rxtshift < 6 &&
5081 		    tp->t_rxtshift % 2 == 0)) {
5082 			/*
5083 			 * Enter Path MTU Black-hole Detection mechanism: -
5084 			 * Disable Path MTU Discovery (IP "DF" bit). -
5085 			 * Reduce MTU to lower value than what we negotiated
5086 			 * with peer.
5087 			 */
5088 			if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) == 0) {
5089 				/*
5090 				 * Record that we may have found a black
5091 				 * hole.
5092 				 */
5093 				tp->t_flags2 |= TF2_PLPMTU_BLACKHOLE;
5094 				/* Keep track of previous MSS. */
5095 				tp->t_pmtud_saved_maxseg = tp->t_maxseg;
5096 			}
5097 			/*
5098 			 * Reduce the MSS to blackhole value or to the
5099 			 * default in an attempt to retransmit.
5100 			 */
5101 #ifdef INET6
5102 			isipv6 = bbr->r_is_v6;
5103 			if (isipv6 &&
5104 			    tp->t_maxseg > V_tcp_v6pmtud_blackhole_mss) {
5105 				/* Use the sysctl tuneable blackhole MSS. */
5106 				tp->t_maxseg = V_tcp_v6pmtud_blackhole_mss;
5107 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated);
5108 			} else if (isipv6) {
5109 				/* Use the default MSS. */
5110 				tp->t_maxseg = V_tcp_v6mssdflt;
5111 				/*
5112 				 * Disable Path MTU Discovery when we switch
5113 				 * to minmss.
5114 				 */
5115 				tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
5116 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
5117 			}
5118 #endif
5119 #if defined(INET6) && defined(INET)
5120 			else
5121 #endif
5122 #ifdef INET
5123 			if (tp->t_maxseg > V_tcp_pmtud_blackhole_mss) {
5124 				/* Use the sysctl tuneable blackhole MSS. */
5125 				tp->t_maxseg = V_tcp_pmtud_blackhole_mss;
5126 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated);
5127 			} else {
5128 				/* Use the default MSS. */
5129 				tp->t_maxseg = V_tcp_mssdflt;
5130 				/*
5131 				 * Disable Path MTU Discovery when we switch
5132 				 * to minmss.
5133 				 */
5134 				tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
5135 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_activated_min_mss);
5136 			}
5137 #endif
5138 		} else {
5139 			/*
5140 			 * If further retransmissions are still unsuccessful
5141 			 * with a lowered MTU, maybe this isn't a blackhole
5142 			 * and we restore the previous MSS and blackhole
5143 			 * detection flags. The limit '6' is determined by
5144 			 * giving each probe stage (1448, 1188, 524) 2
5145 			 * chances to recover.
5146 			 */
5147 			if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) &&
5148 			    (tp->t_rxtshift >= 6)) {
5149 				tp->t_flags2 |= TF2_PLPMTU_PMTUD;
5150 				tp->t_flags2 &= ~TF2_PLPMTU_BLACKHOLE;
5151 				tp->t_maxseg = tp->t_pmtud_saved_maxseg;
5152 				KMOD_TCPSTAT_INC(tcps_pmtud_blackhole_failed);
5153 			}
5154 		}
5155 	}
5156 	/*
5157 	 * Disable RFC1323 and SACK if we haven't got any response to our
5158 	 * third SYN to work-around some broken terminal servers (most of
5159 	 * which have hopefully been retired) that have bad VJ header
5160 	 * compression code which trashes TCP segments containing
5161 	 * unknown-to-them TCP options.
5162 	 */
5163 	if (tcp_rexmit_drop_options && (tp->t_state == TCPS_SYN_SENT) &&
5164 	    (tp->t_rxtshift == 3))
5165 		tp->t_flags &= ~(TF_REQ_SCALE | TF_REQ_TSTMP | TF_SACK_PERMIT);
5166 	/*
5167 	 * If we backed off this far, our srtt estimate is probably bogus.
5168 	 * Clobber it so we'll take the next rtt measurement as our srtt;
5169 	 * move the current srtt into rttvar to keep the current retransmit
5170 	 * times until then.
5171 	 */
5172 	if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
5173 #ifdef INET6
5174 		if (bbr->r_is_v6)
5175 			in6_losing(tp->t_inpcb);
5176 		else
5177 #endif
5178 			in_losing(tp->t_inpcb);
5179 		tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
5180 		tp->t_srtt = 0;
5181 	}
5182 	sack_filter_clear(&bbr->r_ctl.bbr_sf, tp->snd_una);
5183 	tp->snd_recover = tp->snd_max;
5184 	tp->t_flags |= TF_ACKNOW;
5185 	tp->t_rtttime = 0;
5186 out:
5187 	return (retval);
5188 }
5189 
5190 static int
5191 bbr_process_timers(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts, uint8_t hpts_calling)
5192 {
5193 	int32_t ret = 0;
5194 	int32_t timers = (bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK);
5195 
5196 	if (timers == 0) {
5197 		return (0);
5198 	}
5199 	if (tp->t_state == TCPS_LISTEN) {
5200 		/* no timers on listen sockets */
5201 		if (bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)
5202 			return (0);
5203 		return (1);
5204 	}
5205 	if (TSTMP_LT(cts, bbr->r_ctl.rc_timer_exp)) {
5206 		uint32_t left;
5207 
5208 		if (bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) {
5209 			ret = -1;
5210 			bbr_log_to_processing(bbr, cts, ret, 0, hpts_calling);
5211 			return (0);
5212 		}
5213 		if (hpts_calling == 0) {
5214 			ret = -2;
5215 			bbr_log_to_processing(bbr, cts, ret, 0, hpts_calling);
5216 			return (0);
5217 		}
5218 		/*
5219 		 * Ok our timer went off early and we are not paced false
5220 		 * alarm, go back to sleep.
5221 		 */
5222 		left = bbr->r_ctl.rc_timer_exp - cts;
5223 		ret = -3;
5224 		bbr_log_to_processing(bbr, cts, ret, left, hpts_calling);
5225 		tcp_hpts_insert(tp->t_inpcb, HPTS_USEC_TO_SLOTS(left));
5226 		return (1);
5227 	}
5228 	bbr->rc_tmr_stopped = 0;
5229 	bbr->r_ctl.rc_hpts_flags &= ~PACE_TMR_MASK;
5230 	if (timers & PACE_TMR_DELACK) {
5231 		ret = bbr_timeout_delack(tp, bbr, cts);
5232 	} else if (timers & PACE_TMR_PERSIT) {
5233 		ret = bbr_timeout_persist(tp, bbr, cts);
5234 	} else if (timers & PACE_TMR_RACK) {
5235 		bbr->r_ctl.rc_tlp_rxt_last_time = cts;
5236 		ret = bbr_timeout_rack(tp, bbr, cts);
5237 	} else if (timers & PACE_TMR_TLP) {
5238 		bbr->r_ctl.rc_tlp_rxt_last_time = cts;
5239 		ret = bbr_timeout_tlp(tp, bbr, cts);
5240 	} else if (timers & PACE_TMR_RXT) {
5241 		bbr->r_ctl.rc_tlp_rxt_last_time = cts;
5242 		ret = bbr_timeout_rxt(tp, bbr, cts);
5243 	} else if (timers & PACE_TMR_KEEP) {
5244 		ret = bbr_timeout_keepalive(tp, bbr, cts);
5245 	}
5246 	bbr_log_to_processing(bbr, cts, ret, timers, hpts_calling);
5247 	return (ret);
5248 }
5249 
5250 static void
5251 bbr_timer_cancel(struct tcp_bbr *bbr, int32_t line, uint32_t cts)
5252 {
5253 	if (bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK) {
5254 		uint8_t hpts_removed = 0;
5255 
5256 		if (bbr->rc_inp->inp_in_hpts &&
5257 		    (bbr->rc_timer_first == 1)) {
5258 			/*
5259 			 * If we are canceling timer's when we have the
5260 			 * timer ahead of the output being paced. We also
5261 			 * must remove ourselves from the hpts.
5262 			 */
5263 			hpts_removed = 1;
5264 			tcp_hpts_remove(bbr->rc_inp, HPTS_REMOVE_OUTPUT);
5265 			if (bbr->r_ctl.rc_last_delay_val) {
5266 				/* Update the last hptsi delay too */
5267 				uint32_t time_since_send;
5268 
5269 				if (TSTMP_GT(cts, bbr->rc_pacer_started))
5270 					time_since_send = cts - bbr->rc_pacer_started;
5271 				else
5272 					time_since_send = 0;
5273 				if (bbr->r_ctl.rc_last_delay_val > time_since_send) {
5274 					/* Cut down our slot time */
5275 					bbr->r_ctl.rc_last_delay_val -= time_since_send;
5276 				} else {
5277 					bbr->r_ctl.rc_last_delay_val = 0;
5278 				}
5279 				bbr->rc_pacer_started = cts;
5280 			}
5281 		}
5282 		bbr->rc_timer_first = 0;
5283 		bbr_log_to_cancel(bbr, line, cts, hpts_removed);
5284 		bbr->rc_tmr_stopped = bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK;
5285 		bbr->r_ctl.rc_hpts_flags &= ~(PACE_TMR_MASK);
5286 	}
5287 }
5288 
5289 static void
5290 bbr_timer_stop(struct tcpcb *tp, uint32_t timer_type)
5291 {
5292 	struct tcp_bbr *bbr;
5293 
5294 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
5295 	bbr->rc_all_timers_stopped = 1;
5296 	return;
5297 }
5298 
5299 /*
5300  * stop all timers always returning 0.
5301  */
5302 static int
5303 bbr_stopall(struct tcpcb *tp)
5304 {
5305 	return (0);
5306 }
5307 
5308 static void
5309 bbr_timer_activate(struct tcpcb *tp, uint32_t timer_type, uint32_t delta)
5310 {
5311 	return;
5312 }
5313 
5314 /*
5315  * return true if a bbr timer (rack or tlp) is active.
5316  */
5317 static int
5318 bbr_timer_active(struct tcpcb *tp, uint32_t timer_type)
5319 {
5320 	return (0);
5321 }
5322 
5323 static uint32_t
5324 bbr_get_earliest_send_outstanding(struct tcp_bbr *bbr, struct bbr_sendmap *u_rsm, uint32_t cts)
5325 {
5326 	struct bbr_sendmap *rsm;
5327 
5328 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_tmap);
5329 	if ((rsm == NULL) || (u_rsm == rsm))
5330 		return (cts);
5331 	return(rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)]);
5332 }
5333 
5334 static void
5335 bbr_update_rsm(struct tcpcb *tp, struct tcp_bbr *bbr,
5336      struct bbr_sendmap *rsm, uint32_t cts, uint32_t pacing_time)
5337 {
5338 	int32_t idx;
5339 
5340 	rsm->r_rtr_cnt++;
5341 	rsm->r_dupack = 0;
5342 	if (rsm->r_rtr_cnt > BBR_NUM_OF_RETRANS) {
5343 		rsm->r_rtr_cnt = BBR_NUM_OF_RETRANS;
5344 		rsm->r_flags |= BBR_OVERMAX;
5345 	}
5346 	if (rsm->r_flags & BBR_RWND_COLLAPSED) {
5347 		/* Take off the collapsed flag at rxt */
5348 		rsm->r_flags &= ~BBR_RWND_COLLAPSED;
5349 	}
5350 	if (rsm->r_flags & BBR_MARKED_LOST) {
5351 		/* We have retransmitted, its no longer lost */
5352 		rsm->r_flags &= ~BBR_MARKED_LOST;
5353 		bbr->r_ctl.rc_lost_bytes -= rsm->r_end - rsm->r_start;
5354 	}
5355 	if (rsm->r_flags & BBR_RXT_CLEARED) {
5356 		/*
5357 		 * We hit a RXT timer on it and
5358 		 * we cleared the "acked" flag.
5359 		 * We now have it going back into
5360 		 * flight, we can remove the cleared
5361 		 * flag and possibly do accounting on
5362 		 * this piece.
5363 		 */
5364 		rsm->r_flags &= ~BBR_RXT_CLEARED;
5365 	}
5366 	if ((rsm->r_rtr_cnt > 1) && ((rsm->r_flags & BBR_TLP) == 0)) {
5367 		bbr->r_ctl.rc_holes_rxt += (rsm->r_end - rsm->r_start);
5368 		rsm->r_rtr_bytes += (rsm->r_end - rsm->r_start);
5369 	}
5370 	idx = rsm->r_rtr_cnt - 1;
5371 	rsm->r_tim_lastsent[idx] = cts;
5372 	rsm->r_pacing_delay = pacing_time;
5373 	rsm->r_delivered = bbr->r_ctl.rc_delivered;
5374 	rsm->r_ts_valid = bbr->rc_ts_valid;
5375 	if (bbr->rc_ts_valid)
5376 		rsm->r_del_ack_ts = bbr->r_ctl.last_inbound_ts;
5377 	if (bbr->r_ctl.r_app_limited_until)
5378 		rsm->r_app_limited = 1;
5379 	else
5380 		rsm->r_app_limited = 0;
5381 	if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW)
5382 		rsm->r_bbr_state = bbr_state_val(bbr);
5383 	else
5384 		rsm->r_bbr_state = 8;
5385 	if (rsm->r_flags & BBR_ACKED) {
5386 		/* Problably MTU discovery messing with us */
5387 		uint32_t old_flags;
5388 
5389 		old_flags = rsm->r_flags;
5390 		rsm->r_flags &= ~BBR_ACKED;
5391 		bbr_log_type_rsmclear(bbr, cts, rsm, old_flags, __LINE__);
5392 		bbr->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
5393 		if (bbr->r_ctl.rc_sacked == 0)
5394 			bbr->r_ctl.rc_sacklast = NULL;
5395 	}
5396 	if (rsm->r_in_tmap) {
5397 		TAILQ_REMOVE(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
5398 	}
5399 	TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
5400 	rsm->r_in_tmap = 1;
5401 	if (rsm->r_flags & BBR_SACK_PASSED) {
5402 		/* We have retransmitted due to the SACK pass */
5403 		rsm->r_flags &= ~BBR_SACK_PASSED;
5404 		rsm->r_flags |= BBR_WAS_SACKPASS;
5405 	}
5406 	rsm->r_first_sent_time = bbr_get_earliest_send_outstanding(bbr, rsm, cts);
5407 	rsm->r_flight_at_send = ctf_flight_size(bbr->rc_tp,
5408 						(bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
5409 	bbr->r_ctl.rc_next = TAILQ_NEXT(rsm, r_next);
5410 	if (bbr->r_ctl.rc_bbr_hptsi_gain > BBR_UNIT) {
5411 		rsm->r_is_gain = 1;
5412 		rsm->r_is_drain = 0;
5413 	} else if (bbr->r_ctl.rc_bbr_hptsi_gain < BBR_UNIT) {
5414 		rsm->r_is_drain = 1;
5415 		rsm->r_is_gain = 0;
5416 	} else {
5417 		rsm->r_is_drain = 0;
5418 		rsm->r_is_gain = 0;
5419 	}
5420 	rsm->r_del_time = bbr->r_ctl.rc_del_time; /* TEMP GOOGLE CODE */
5421 }
5422 
5423 /*
5424  * Returns 0, or the sequence where we stopped
5425  * updating. We also update the lenp to be the amount
5426  * of data left.
5427  */
5428 
5429 static uint32_t
5430 bbr_update_entry(struct tcpcb *tp, struct tcp_bbr *bbr,
5431     struct bbr_sendmap *rsm, uint32_t cts, int32_t *lenp, uint32_t pacing_time)
5432 {
5433 	/*
5434 	 * We (re-)transmitted starting at rsm->r_start for some length
5435 	 * (possibly less than r_end.
5436 	 */
5437 	struct bbr_sendmap *nrsm;
5438 	uint32_t c_end;
5439 	int32_t len;
5440 
5441 	len = *lenp;
5442 	c_end = rsm->r_start + len;
5443 	if (SEQ_GEQ(c_end, rsm->r_end)) {
5444 		/*
5445 		 * We retransmitted the whole piece or more than the whole
5446 		 * slopping into the next rsm.
5447 		 */
5448 		bbr_update_rsm(tp, bbr, rsm, cts, pacing_time);
5449 		if (c_end == rsm->r_end) {
5450 			*lenp = 0;
5451 			return (0);
5452 		} else {
5453 			int32_t act_len;
5454 
5455 			/* Hangs over the end return whats left */
5456 			act_len = rsm->r_end - rsm->r_start;
5457 			*lenp = (len - act_len);
5458 			return (rsm->r_end);
5459 		}
5460 		/* We don't get out of this block. */
5461 	}
5462 	/*
5463 	 * Here we retransmitted less than the whole thing which means we
5464 	 * have to split this into what was transmitted and what was not.
5465 	 */
5466 	nrsm = bbr_alloc_full_limit(bbr);
5467 	if (nrsm == NULL) {
5468 		*lenp = 0;
5469 		return (0);
5470 	}
5471 	/*
5472 	 * So here we are going to take the original rsm and make it what we
5473 	 * retransmitted. nrsm will be the tail portion we did not
5474 	 * retransmit. For example say the chunk was 1, 11 (10 bytes). And
5475 	 * we retransmitted 5 bytes i.e. 1, 5. The original piece shrinks to
5476 	 * 1, 6 and the new piece will be 6, 11.
5477 	 */
5478 	bbr_clone_rsm(bbr, nrsm, rsm, c_end);
5479 	TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_map, rsm, nrsm, r_next);
5480 	nrsm->r_dupack = 0;
5481 	if (rsm->r_in_tmap) {
5482 		TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
5483 		nrsm->r_in_tmap = 1;
5484 	}
5485 	rsm->r_flags &= (~BBR_HAS_FIN);
5486 	bbr_update_rsm(tp, bbr, rsm, cts, pacing_time);
5487 	*lenp = 0;
5488 	return (0);
5489 }
5490 
5491 static uint64_t
5492 bbr_get_hardware_rate(struct tcp_bbr *bbr)
5493 {
5494 	uint64_t bw;
5495 
5496 	bw = bbr_get_bw(bbr);
5497 	bw *= (uint64_t)bbr_hptsi_gain[BBR_SUB_GAIN];
5498 	bw /= (uint64_t)BBR_UNIT;
5499 	return(bw);
5500 }
5501 
5502 static void
5503 bbr_setup_less_of_rate(struct tcp_bbr *bbr, uint32_t cts,
5504 		       uint64_t act_rate, uint64_t rate_wanted)
5505 {
5506 	/*
5507 	 * We could not get a full gains worth
5508 	 * of rate.
5509 	 */
5510 	if (get_filter_value(&bbr->r_ctl.rc_delrate) >= act_rate) {
5511 		/* we can't even get the real rate */
5512 		uint64_t red;
5513 
5514 		bbr->skip_gain = 1;
5515 		bbr->gain_is_limited = 0;
5516 		red = get_filter_value(&bbr->r_ctl.rc_delrate) - act_rate;
5517 		if (red)
5518 			filter_reduce_by(&bbr->r_ctl.rc_delrate, red, cts);
5519 	} else {
5520 		/* We can use a lower gain */
5521 		bbr->skip_gain = 0;
5522 		bbr->gain_is_limited = 1;
5523 	}
5524 }
5525 
5526 static void
5527 bbr_update_hardware_pacing_rate(struct tcp_bbr *bbr, uint32_t cts)
5528 {
5529 	const struct tcp_hwrate_limit_table *nrte;
5530 	int error, rate = -1;
5531 
5532 	if (bbr->r_ctl.crte == NULL)
5533 		return;
5534 	if ((bbr->rc_inp->inp_route.ro_nh == NULL) ||
5535 	    (bbr->rc_inp->inp_route.ro_nh->nh_ifp == NULL)) {
5536 		/* Lost our routes? */
5537 		/* Clear the way for a re-attempt */
5538 		bbr->bbr_attempt_hdwr_pace = 0;
5539 lost_rate:
5540 		bbr->gain_is_limited = 0;
5541 		bbr->skip_gain = 0;
5542 		bbr->bbr_hdrw_pacing = 0;
5543 		counter_u64_add(bbr_flows_whdwr_pacing, -1);
5544 		counter_u64_add(bbr_flows_nohdwr_pacing, 1);
5545 		tcp_bbr_tso_size_check(bbr, cts);
5546 		return;
5547 	}
5548 	rate = bbr_get_hardware_rate(bbr);
5549 	nrte = tcp_chg_pacing_rate(bbr->r_ctl.crte,
5550 				   bbr->rc_tp,
5551 				   bbr->rc_inp->inp_route.ro_nh->nh_ifp,
5552 				   rate,
5553 				   (RS_PACING_GEQ|RS_PACING_SUB_OK),
5554 				   &error);
5555 	if (nrte == NULL) {
5556 		goto lost_rate;
5557 	}
5558 	if (nrte != bbr->r_ctl.crte) {
5559 		bbr->r_ctl.crte = nrte;
5560 		if (error == 0)  {
5561 			BBR_STAT_INC(bbr_hdwr_rl_mod_ok);
5562 			if (bbr->r_ctl.crte->rate < rate) {
5563 				/* We have a problem */
5564 				bbr_setup_less_of_rate(bbr, cts,
5565 						       bbr->r_ctl.crte->rate, rate);
5566 			} else {
5567 				/* We are good */
5568 				bbr->gain_is_limited = 0;
5569 				bbr->skip_gain = 0;
5570 			}
5571 		} else {
5572 			/* A failure should release the tag */
5573 			BBR_STAT_INC(bbr_hdwr_rl_mod_fail);
5574 			bbr->gain_is_limited = 0;
5575 			bbr->skip_gain = 0;
5576 			bbr->bbr_hdrw_pacing = 0;
5577 		}
5578 		bbr_type_log_hdwr_pacing(bbr,
5579 					 bbr->r_ctl.crte->ptbl->rs_ifp,
5580 					 rate,
5581 					 ((bbr->r_ctl.crte == NULL) ? 0 : bbr->r_ctl.crte->rate),
5582 					 __LINE__,
5583 					 cts,
5584 					 error);
5585 	}
5586 }
5587 
5588 static void
5589 bbr_adjust_for_hw_pacing(struct tcp_bbr *bbr, uint32_t cts)
5590 {
5591 	/*
5592 	 * If we have hardware pacing support
5593 	 * we need to factor that in for our
5594 	 * TSO size.
5595 	 */
5596 	const struct tcp_hwrate_limit_table *rlp;
5597 	uint32_t cur_delay, seg_sz, maxseg, new_tso, delta, hdwr_delay;
5598 
5599 	if ((bbr->bbr_hdrw_pacing == 0) ||
5600 	    (IN_RECOVERY(bbr->rc_tp->t_flags)) ||
5601 	    (bbr->r_ctl.crte == NULL))
5602 		return;
5603 	if (bbr->hw_pacing_set == 0) {
5604 		/* Not yet by the hdwr pacing count delay */
5605 		return;
5606 	}
5607 	if (bbr_hdwr_pace_adjust == 0) {
5608 		/* No adjustment */
5609 		return;
5610 	}
5611 	rlp = bbr->r_ctl.crte;
5612 	if (bbr->rc_tp->t_maxseg > bbr->rc_last_options)
5613 		maxseg = bbr->rc_tp->t_maxseg - bbr->rc_last_options;
5614 	else
5615 		maxseg = BBR_MIN_SEG - bbr->rc_last_options;
5616 	/*
5617 	 * So lets first get the
5618 	 * time we will take between
5619 	 * TSO sized sends currently without
5620 	 * hardware help.
5621 	 */
5622 	cur_delay = bbr_get_pacing_delay(bbr, BBR_UNIT,
5623 		        bbr->r_ctl.rc_pace_max_segs, cts, 1);
5624 	hdwr_delay = bbr->r_ctl.rc_pace_max_segs / maxseg;
5625 	hdwr_delay *= rlp->time_between;
5626 	if (cur_delay > hdwr_delay)
5627 		delta = cur_delay - hdwr_delay;
5628 	else
5629 		delta = 0;
5630 	bbr_log_type_tsosize(bbr, cts, delta, cur_delay, hdwr_delay,
5631 			     (bbr->r_ctl.rc_pace_max_segs / maxseg),
5632 			     1);
5633 	if (delta &&
5634 	    (delta < (max(rlp->time_between,
5635 			  bbr->r_ctl.bbr_hptsi_segments_delay_tar)))) {
5636 		/*
5637 		 * Now lets divide by the pacing
5638 		 * time between each segment the
5639 		 * hardware sends rounding up and
5640 		 * derive a bytes from that. We multiply
5641 		 * that by bbr_hdwr_pace_adjust to get
5642 		 * more bang for our buck.
5643 		 *
5644 		 * The goal is to have the software pacer
5645 		 * waiting no more than an additional
5646 		 * pacing delay if we can (without the
5647 		 * compensation i.e. x bbr_hdwr_pace_adjust).
5648 		 */
5649 		seg_sz = max(((cur_delay + rlp->time_between)/rlp->time_between),
5650 			     (bbr->r_ctl.rc_pace_max_segs/maxseg));
5651 		seg_sz *= bbr_hdwr_pace_adjust;
5652 		if (bbr_hdwr_pace_floor &&
5653 		    (seg_sz < bbr->r_ctl.crte->ptbl->rs_min_seg)) {
5654 			/* Currently hardware paces
5655 			 * out rs_min_seg segments at a time.
5656 			 * We need to make sure we always send at least
5657 			 * a full burst of bbr_hdwr_pace_floor down.
5658 			 */
5659 			seg_sz = bbr->r_ctl.crte->ptbl->rs_min_seg;
5660 		}
5661 		seg_sz *= maxseg;
5662 	} else if (delta == 0) {
5663 		/*
5664 		 * The highest pacing rate is
5665 		 * above our b/w gained. This means
5666 		 * we probably are going quite fast at
5667 		 * the hardware highest rate. Lets just multiply
5668 		 * the calculated TSO size by the
5669 		 * multiplier factor (its probably
5670 		 * 4 segments in the default config for
5671 		 * mlx).
5672 		 */
5673 		seg_sz = bbr->r_ctl.rc_pace_max_segs * bbr_hdwr_pace_adjust;
5674 		if (bbr_hdwr_pace_floor &&
5675 		    (seg_sz < bbr->r_ctl.crte->ptbl->rs_min_seg)) {
5676 			/* Currently hardware paces
5677 			 * out rs_min_seg segments at a time.
5678 			 * We need to make sure we always send at least
5679 			 * a full burst of bbr_hdwr_pace_floor down.
5680 			 */
5681 			seg_sz = bbr->r_ctl.crte->ptbl->rs_min_seg;
5682 		}
5683 	} else {
5684 		/*
5685 		 * The pacing time difference is so
5686 		 * big that the hardware will
5687 		 * pace out more rapidly then we
5688 		 * really want and then we
5689 		 * will have a long delay. Lets just keep
5690 		 * the same TSO size so its as if
5691 		 * we were not using hdwr pacing (we
5692 		 * just gain a bit of spacing from the
5693 		 * hardware if seg_sz > 1).
5694 		 */
5695 		seg_sz = bbr->r_ctl.rc_pace_max_segs;
5696 	}
5697 	if (seg_sz > bbr->r_ctl.rc_pace_max_segs)
5698 		new_tso = seg_sz;
5699 	else
5700 		new_tso = bbr->r_ctl.rc_pace_max_segs;
5701 	if (new_tso >= (PACE_MAX_IP_BYTES-maxseg))
5702 		new_tso = PACE_MAX_IP_BYTES - maxseg;
5703 
5704 	if (new_tso != bbr->r_ctl.rc_pace_max_segs) {
5705 		bbr_log_type_tsosize(bbr, cts, new_tso, 0, bbr->r_ctl.rc_pace_max_segs, maxseg, 0);
5706 		bbr->r_ctl.rc_pace_max_segs = new_tso;
5707 	}
5708 }
5709 
5710 static void
5711 tcp_bbr_tso_size_check(struct tcp_bbr *bbr, uint32_t cts)
5712 {
5713 	uint64_t bw;
5714 	uint32_t old_tso = 0, new_tso;
5715 	uint32_t maxseg, bytes;
5716 	uint32_t tls_seg=0;
5717 	/*
5718 	 * Google/linux uses the following algorithm to determine
5719 	 * the TSO size based on the b/w of the link (from Neal Cardwell email 9/27/18):
5720 	 *
5721 	 *  bytes = bw_in_bytes_per_second / 1000
5722 	 *  bytes = min(bytes, 64k)
5723 	 *  tso_segs = bytes / MSS
5724 	 *  if (bw < 1.2Mbs)
5725 	 *      min_tso_segs = 1
5726 	 *  else
5727 	 *	min_tso_segs = 2
5728 	 * tso_segs = max(tso_segs, min_tso_segs)
5729 	 *
5730 	 * * Note apply a device specific limit (we apply this in the
5731 	 *   tcp_m_copym).
5732 	 * Note that before the initial measurement is made google bursts out
5733 	 * a full iwnd just like new-reno/cubic.
5734 	 *
5735 	 * We do not use this algorithm. Instead we
5736 	 * use a two phased approach:
5737 	 *
5738 	 *  if ( bw <= per-tcb-cross-over)
5739 	 *     goal_tso =  calculate how much with this bw we
5740 	 *                 can send in goal-time seconds.
5741 	 *     if (goal_tso > mss)
5742 	 *         seg = goal_tso / mss
5743 	 *         tso = seg * mss
5744 	 *     else
5745          *         tso = mss
5746 	 *     if (tso > per-tcb-max)
5747 	 *         tso = per-tcb-max
5748 	 *  else if ( bw > 512Mbps)
5749 	 *     tso = max-tso (64k/mss)
5750 	 *  else
5751 	 *     goal_tso = bw / per-tcb-divsor
5752 	 *     seg = (goal_tso + mss-1)/mss
5753 	 *     tso = seg * mss
5754 	 *
5755 	 * if (tso < per-tcb-floor)
5756 	 *    tso = per-tcb-floor
5757 	 * if (tso > per-tcb-utter_max)
5758 	 *    tso = per-tcb-utter_max
5759 	 *
5760 	 * Note the default per-tcb-divisor is 1000 (same as google).
5761 	 * the goal cross over is 30Mbps however. To recreate googles
5762 	 * algorithm you need to set:
5763 	 *
5764 	 * cross-over = 23,168,000 bps
5765 	 * goal-time = 18000
5766 	 * per-tcb-max = 2
5767 	 * per-tcb-divisor = 1000
5768 	 * per-tcb-floor = 1
5769 	 *
5770 	 * This will get you "google bbr" behavior with respect to tso size.
5771 	 *
5772 	 * Note we do set anything TSO size until we are past the initial
5773 	 * window. Before that we gnerally use either a single MSS
5774 	 * or we use the full IW size (so we burst a IW at a time)
5775 	 */
5776 
5777 	if (bbr->rc_tp->t_maxseg > bbr->rc_last_options) {
5778 		maxseg = bbr->rc_tp->t_maxseg - bbr->rc_last_options;
5779 	} else {
5780 		maxseg = BBR_MIN_SEG - bbr->rc_last_options;
5781 	}
5782 	old_tso = bbr->r_ctl.rc_pace_max_segs;
5783 	if (bbr->rc_past_init_win == 0) {
5784 		/*
5785 		 * Not enough data has been acknowledged to make a
5786 		 * judgement. Set up the initial TSO based on if we
5787 		 * are sending a full IW at once or not.
5788 		 */
5789 		if (bbr->rc_use_google)
5790 			bbr->r_ctl.rc_pace_max_segs = ((bbr->rc_tp->t_maxseg - bbr->rc_last_options) * 2);
5791 		else if (bbr->bbr_init_win_cheat)
5792 			bbr->r_ctl.rc_pace_max_segs = bbr_initial_cwnd(bbr, bbr->rc_tp);
5793 		else
5794 			bbr->r_ctl.rc_pace_max_segs = bbr->rc_tp->t_maxseg - bbr->rc_last_options;
5795 		if (bbr->r_ctl.rc_pace_min_segs != bbr->rc_tp->t_maxseg)
5796 			bbr->r_ctl.rc_pace_min_segs = bbr->rc_tp->t_maxseg;
5797 		if (bbr->r_ctl.rc_pace_max_segs == 0) {
5798 			bbr->r_ctl.rc_pace_max_segs = maxseg;
5799 		}
5800 		bbr_log_type_tsosize(bbr, cts, bbr->r_ctl.rc_pace_max_segs, tls_seg, old_tso, maxseg, 0);
5801 			bbr_adjust_for_hw_pacing(bbr, cts);
5802 		return;
5803 	}
5804 	/**
5805 	 * Now lets set the TSO goal based on our delivery rate in
5806 	 * bytes per second. Note we only do this if
5807 	 * we have acked at least the initial cwnd worth of data.
5808 	 */
5809 	bw = bbr_get_bw(bbr);
5810 	if (IN_RECOVERY(bbr->rc_tp->t_flags) &&
5811 	     (bbr->rc_use_google == 0)) {
5812 		/* We clamp to one MSS in recovery */
5813 		new_tso = maxseg;
5814 	} else if (bbr->rc_use_google) {
5815 		int min_tso_segs;
5816 
5817 		/* Google considers the gain too */
5818 		if (bbr->r_ctl.rc_bbr_hptsi_gain != BBR_UNIT) {
5819 			bw *= bbr->r_ctl.rc_bbr_hptsi_gain;
5820 			bw /= BBR_UNIT;
5821 		}
5822 		bytes = bw / 1024;
5823 		if (bytes > (64 * 1024))
5824 			bytes = 64 * 1024;
5825 		new_tso = bytes / maxseg;
5826 		if (bw < ONE_POINT_TWO_MEG)
5827 			min_tso_segs = 1;
5828 		else
5829 			min_tso_segs = 2;
5830 		if (new_tso < min_tso_segs)
5831 			new_tso = min_tso_segs;
5832 		new_tso *= maxseg;
5833 	} else if (bbr->rc_no_pacing) {
5834 		new_tso = (PACE_MAX_IP_BYTES / maxseg) * maxseg;
5835 	} else if (bw <= bbr->r_ctl.bbr_cross_over) {
5836 		/*
5837 		 * Calculate the worse case b/w TSO if we are inserting no
5838 		 * more than a delay_target number of TSO's.
5839 		 */
5840 		uint32_t tso_len, min_tso;
5841 
5842 		tso_len = bbr_get_pacing_length(bbr, BBR_UNIT, bbr->r_ctl.bbr_hptsi_segments_delay_tar, bw);
5843 		if (tso_len > maxseg) {
5844 			new_tso = tso_len / maxseg;
5845 			if (new_tso > bbr->r_ctl.bbr_hptsi_segments_max)
5846 				new_tso = bbr->r_ctl.bbr_hptsi_segments_max;
5847 			new_tso *= maxseg;
5848 		} else {
5849 			/*
5850 			 * less than a full sized frame yikes.. long rtt or
5851 			 * low bw?
5852 			 */
5853 			min_tso = bbr_minseg(bbr);
5854 			if ((tso_len > min_tso) && (bbr_all_get_min == 0))
5855 				new_tso = rounddown(tso_len, min_tso);
5856 			else
5857 				new_tso = min_tso;
5858 		}
5859 	} else if (bw > FIVETWELVE_MBPS) {
5860 		/*
5861 		 * This guy is so fast b/w wise that we can TSO as large as
5862 		 * possible of segments that the NIC will allow.
5863 		 */
5864 		new_tso = rounddown(PACE_MAX_IP_BYTES, maxseg);
5865 	} else {
5866 		/*
5867 		 * This formula is based on attempting to send a segment or
5868 		 * more every bbr_hptsi_per_second. The default is 1000
5869 		 * which means you are targeting what you can send every 1ms
5870 		 * based on the peers bw.
5871 		 *
5872 		 * If the number drops to say 500, then you are looking more
5873 		 * at 2ms and you will raise how much we send in a single
5874 		 * TSO thus saving CPU (less bbr_output_wtime() calls). The
5875 		 * trade off of course is you will send more at once and
5876 		 * thus tend to clump up the sends into larger "bursts"
5877 		 * building a queue.
5878 		 */
5879 		bw /= bbr->r_ctl.bbr_hptsi_per_second;
5880 		new_tso = roundup(bw, (uint64_t)maxseg);
5881 		/*
5882 		 * Gate the floor to match what our lower than 48Mbps
5883 		 * algorithm does. The ceiling (bbr_hptsi_segments_max) thus
5884 		 * becomes the floor for this calculation.
5885 		 */
5886 		if (new_tso < (bbr->r_ctl.bbr_hptsi_segments_max * maxseg))
5887 			new_tso = (bbr->r_ctl.bbr_hptsi_segments_max * maxseg);
5888 	}
5889 	if (bbr->r_ctl.bbr_hptsi_segments_floor && (new_tso < (maxseg * bbr->r_ctl.bbr_hptsi_segments_floor)))
5890 		new_tso = maxseg * bbr->r_ctl.bbr_hptsi_segments_floor;
5891 	if (new_tso > PACE_MAX_IP_BYTES)
5892 		new_tso = rounddown(PACE_MAX_IP_BYTES, maxseg);
5893 	/* Enforce an utter maximum. */
5894 	if (bbr->r_ctl.bbr_utter_max && (new_tso > (bbr->r_ctl.bbr_utter_max * maxseg))) {
5895 		new_tso = bbr->r_ctl.bbr_utter_max * maxseg;
5896 	}
5897 	if (old_tso != new_tso) {
5898 		/* Only log changes */
5899 		bbr_log_type_tsosize(bbr, cts, new_tso, tls_seg, old_tso, maxseg, 0);
5900 		bbr->r_ctl.rc_pace_max_segs = new_tso;
5901 	}
5902 	/* We have hardware pacing! */
5903 	bbr_adjust_for_hw_pacing(bbr, cts);
5904 }
5905 
5906 static void
5907 bbr_log_output(struct tcp_bbr *bbr, struct tcpcb *tp, struct tcpopt *to, int32_t len,
5908     uint32_t seq_out, uint8_t th_flags, int32_t err, uint32_t cts,
5909     struct mbuf *mb, int32_t * abandon, struct bbr_sendmap *hintrsm, uint32_t delay_calc,
5910     struct sockbuf *sb)
5911 {
5912 
5913 	struct bbr_sendmap *rsm, *nrsm;
5914 	register uint32_t snd_max, snd_una;
5915 	uint32_t pacing_time;
5916 	/*
5917 	 * Add to the RACK log of packets in flight or retransmitted. If
5918 	 * there is a TS option we will use the TS echoed, if not we will
5919 	 * grab a TS.
5920 	 *
5921 	 * Retransmissions will increment the count and move the ts to its
5922 	 * proper place. Note that if options do not include TS's then we
5923 	 * won't be able to effectively use the ACK for an RTT on a retran.
5924 	 *
5925 	 * Notes about r_start and r_end. Lets consider a send starting at
5926 	 * sequence 1 for 10 bytes. In such an example the r_start would be
5927 	 * 1 (starting sequence) but the r_end would be r_start+len i.e. 11.
5928 	 * This means that r_end is actually the first sequence for the next
5929 	 * slot (11).
5930 	 *
5931 	 */
5932 	INP_WLOCK_ASSERT(tp->t_inpcb);
5933 	if (err) {
5934 		/*
5935 		 * We don't log errors -- we could but snd_max does not
5936 		 * advance in this case either.
5937 		 */
5938 		return;
5939 	}
5940 	if (th_flags & TH_RST) {
5941 		/*
5942 		 * We don't log resets and we return immediately from
5943 		 * sending
5944 		 */
5945 		*abandon = 1;
5946 		return;
5947 	}
5948 	snd_una = tp->snd_una;
5949 	if (th_flags & (TH_SYN | TH_FIN) && (hintrsm == NULL)) {
5950 		/*
5951 		 * The call to bbr_log_output is made before bumping
5952 		 * snd_max. This means we can record one extra byte on a SYN
5953 		 * or FIN if seq_out is adding more on and a FIN is present
5954 		 * (and we are not resending).
5955 		 */
5956 		if ((th_flags & TH_SYN) && (tp->iss == seq_out))
5957 			len++;
5958 		if (th_flags & TH_FIN)
5959 			len++;
5960 	}
5961 	if (SEQ_LEQ((seq_out + len), snd_una)) {
5962 		/* Are sending an old segment to induce an ack (keep-alive)? */
5963 		return;
5964 	}
5965 	if (SEQ_LT(seq_out, snd_una)) {
5966 		/* huh? should we panic? */
5967 		uint32_t end;
5968 
5969 		end = seq_out + len;
5970 		seq_out = snd_una;
5971 		len = end - seq_out;
5972 	}
5973 	snd_max = tp->snd_max;
5974 	if (len == 0) {
5975 		/* We don't log zero window probes */
5976 		return;
5977 	}
5978 	pacing_time = bbr_get_pacing_delay(bbr, bbr->r_ctl.rc_bbr_hptsi_gain, len, cts, 1);
5979 	/* First question is it a retransmission? */
5980 	if (seq_out == snd_max) {
5981 again:
5982 		rsm = bbr_alloc(bbr);
5983 		if (rsm == NULL) {
5984 			return;
5985 		}
5986 		rsm->r_flags = 0;
5987 		if (th_flags & TH_SYN)
5988 			rsm->r_flags |= BBR_HAS_SYN;
5989 		if (th_flags & TH_FIN)
5990 			rsm->r_flags |= BBR_HAS_FIN;
5991 		rsm->r_tim_lastsent[0] = cts;
5992 		rsm->r_rtr_cnt = 1;
5993 		rsm->r_rtr_bytes = 0;
5994 		rsm->r_start = seq_out;
5995 		rsm->r_end = rsm->r_start + len;
5996 		rsm->r_dupack = 0;
5997 		rsm->r_delivered = bbr->r_ctl.rc_delivered;
5998 		rsm->r_pacing_delay = pacing_time;
5999 		rsm->r_ts_valid = bbr->rc_ts_valid;
6000 		if (bbr->rc_ts_valid)
6001 			rsm->r_del_ack_ts = bbr->r_ctl.last_inbound_ts;
6002 		rsm->r_del_time = bbr->r_ctl.rc_del_time;
6003 		if (bbr->r_ctl.r_app_limited_until)
6004 			rsm->r_app_limited = 1;
6005 		else
6006 			rsm->r_app_limited = 0;
6007 		rsm->r_first_sent_time = bbr_get_earliest_send_outstanding(bbr, rsm, cts);
6008 		rsm->r_flight_at_send = ctf_flight_size(bbr->rc_tp,
6009 						(bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
6010 		/*
6011 		 * Here we must also add in this rsm since snd_max
6012 		 * is updated after we return from a new send.
6013 		 */
6014 		rsm->r_flight_at_send += len;
6015 		TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_map, rsm, r_next);
6016 		TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
6017 		rsm->r_in_tmap = 1;
6018 		if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW)
6019 			rsm->r_bbr_state = bbr_state_val(bbr);
6020 		else
6021 			rsm->r_bbr_state = 8;
6022 		if (bbr->r_ctl.rc_bbr_hptsi_gain > BBR_UNIT) {
6023 			rsm->r_is_gain = 1;
6024 			rsm->r_is_drain = 0;
6025 		} else if (bbr->r_ctl.rc_bbr_hptsi_gain < BBR_UNIT) {
6026 			rsm->r_is_drain = 1;
6027 			rsm->r_is_gain = 0;
6028 		} else {
6029 			rsm->r_is_drain = 0;
6030 			rsm->r_is_gain = 0;
6031 		}
6032 		return;
6033 	}
6034 	/*
6035 	 * If we reach here its a retransmission and we need to find it.
6036 	 */
6037 more:
6038 	if (hintrsm && (hintrsm->r_start == seq_out)) {
6039 		rsm = hintrsm;
6040 		hintrsm = NULL;
6041 	} else if (bbr->r_ctl.rc_next) {
6042 		/* We have a hint from a previous run */
6043 		rsm = bbr->r_ctl.rc_next;
6044 	} else {
6045 		/* No hints sorry */
6046 		rsm = NULL;
6047 	}
6048 	if ((rsm) && (rsm->r_start == seq_out)) {
6049 		/*
6050 		 * We used rc_next or hintrsm  to retransmit, hopefully the
6051 		 * likely case.
6052 		 */
6053 		seq_out = bbr_update_entry(tp, bbr, rsm, cts, &len, pacing_time);
6054 		if (len == 0) {
6055 			return;
6056 		} else {
6057 			goto more;
6058 		}
6059 	}
6060 	/* Ok it was not the last pointer go through it the hard way. */
6061 	TAILQ_FOREACH(rsm, &bbr->r_ctl.rc_map, r_next) {
6062 		if (rsm->r_start == seq_out) {
6063 			seq_out = bbr_update_entry(tp, bbr, rsm, cts, &len, pacing_time);
6064 			bbr->r_ctl.rc_next = TAILQ_NEXT(rsm, r_next);
6065 			if (len == 0) {
6066 				return;
6067 			} else {
6068 				continue;
6069 			}
6070 		}
6071 		if (SEQ_GEQ(seq_out, rsm->r_start) && SEQ_LT(seq_out, rsm->r_end)) {
6072 			/* Transmitted within this piece */
6073 			/*
6074 			 * Ok we must split off the front and then let the
6075 			 * update do the rest
6076 			 */
6077 			nrsm = bbr_alloc_full_limit(bbr);
6078 			if (nrsm == NULL) {
6079 				bbr_update_rsm(tp, bbr, rsm, cts, pacing_time);
6080 				return;
6081 			}
6082 			/*
6083 			 * copy rsm to nrsm and then trim the front of rsm
6084 			 * to not include this part.
6085 			 */
6086 			bbr_clone_rsm(bbr, nrsm, rsm, seq_out);
6087 			TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_map, rsm, nrsm, r_next);
6088 			if (rsm->r_in_tmap) {
6089 				TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
6090 				nrsm->r_in_tmap = 1;
6091 			}
6092 			rsm->r_flags &= (~BBR_HAS_FIN);
6093 			seq_out = bbr_update_entry(tp, bbr, nrsm, cts, &len, pacing_time);
6094 			if (len == 0) {
6095 				return;
6096 			}
6097 		}
6098 	}
6099 	/*
6100 	 * Hmm not found in map did they retransmit both old and on into the
6101 	 * new?
6102 	 */
6103 	if (seq_out == tp->snd_max) {
6104 		goto again;
6105 	} else if (SEQ_LT(seq_out, tp->snd_max)) {
6106 #ifdef BBR_INVARIANTS
6107 		printf("seq_out:%u len:%d snd_una:%u snd_max:%u -- but rsm not found?\n",
6108 		    seq_out, len, tp->snd_una, tp->snd_max);
6109 		printf("Starting Dump of all rack entries\n");
6110 		TAILQ_FOREACH(rsm, &bbr->r_ctl.rc_map, r_next) {
6111 			printf("rsm:%p start:%u end:%u\n",
6112 			    rsm, rsm->r_start, rsm->r_end);
6113 		}
6114 		printf("Dump complete\n");
6115 		panic("seq_out not found rack:%p tp:%p",
6116 		    bbr, tp);
6117 #endif
6118 	} else {
6119 #ifdef BBR_INVARIANTS
6120 		/*
6121 		 * Hmm beyond sndmax? (only if we are using the new rtt-pack
6122 		 * flag)
6123 		 */
6124 		panic("seq_out:%u(%d) is beyond snd_max:%u tp:%p",
6125 		    seq_out, len, tp->snd_max, tp);
6126 #endif
6127 	}
6128 }
6129 
6130 static void
6131 bbr_collapse_rtt(struct tcpcb *tp, struct tcp_bbr *bbr, int32_t rtt)
6132 {
6133 	/*
6134 	 * Collapse timeout back the cum-ack moved.
6135 	 */
6136 	tp->t_rxtshift = 0;
6137 	tp->t_softerror = 0;
6138 }
6139 
6140 static void
6141 tcp_bbr_xmit_timer(struct tcp_bbr *bbr, uint32_t rtt_usecs, uint32_t rsm_send_time, uint32_t r_start, uint32_t tsin)
6142 {
6143 	bbr->rtt_valid = 1;
6144 	bbr->r_ctl.cur_rtt = rtt_usecs;
6145 	bbr->r_ctl.ts_in = tsin;
6146 	if (rsm_send_time)
6147 		bbr->r_ctl.cur_rtt_send_time = rsm_send_time;
6148 }
6149 
6150 static void
6151 bbr_make_timestamp_determination(struct tcp_bbr *bbr)
6152 {
6153 	/**
6154 	 * We have in our bbr control:
6155 	 * 1) The timestamp we started observing cum-acks (bbr->r_ctl.bbr_ts_check_tstmp).
6156 	 * 2) Our timestamp indicating when we sent that packet (bbr->r_ctl.rsm->bbr_ts_check_our_cts).
6157 	 * 3) The current timestamp that just came in (bbr->r_ctl.last_inbound_ts)
6158 	 * 4) The time that the packet that generated that ack was sent (bbr->r_ctl.cur_rtt_send_time)
6159 	 *
6160 	 * Now we can calculate the time between the sends by doing:
6161 	 *
6162 	 * delta = bbr->r_ctl.cur_rtt_send_time - bbr->r_ctl.bbr_ts_check_our_cts
6163 	 *
6164 	 * And the peer's time between receiving them by doing:
6165 	 *
6166 	 * peer_delta = bbr->r_ctl.last_inbound_ts - bbr->r_ctl.bbr_ts_check_tstmp
6167 	 *
6168 	 * We want to figure out if the timestamp values are in msec, 10msec or usec.
6169 	 * We also may find that we can't use the timestamps if say we see
6170 	 * that the peer_delta indicates that though we may have taken 10ms to
6171 	 * pace out the data, it only saw 1ms between the two packets. This would
6172 	 * indicate that somewhere on the path is a batching entity that is giving
6173 	 * out time-slices of the actual b/w. This would mean we could not use
6174 	 * reliably the peers timestamps.
6175 	 *
6176 	 * We expect delta > peer_delta initially. Until we figure out the
6177 	 * timestamp difference which we will store in bbr->r_ctl.bbr_peer_tsratio.
6178 	 * If we place 1000 there then its a ms vs our usec. If we place 10000 there
6179 	 * then its 10ms vs our usec. If the peer is running a usec clock we would
6180 	 * put a 1 there. If the value is faster then ours, we will disable the
6181 	 * use of timestamps (though we could revist this later if we find it to be not
6182 	 * just an isolated one or two flows)).
6183 	 *
6184 	 * To detect the batching middle boxes we will come up with our compensation and
6185 	 * if with it in place, we find the peer is drastically off (by some margin) in
6186 	 * the smaller direction, then we will assume the worst case and disable use of timestamps.
6187 	 *
6188 	 */
6189 	uint64_t delta, peer_delta, delta_up;
6190 
6191 	delta = bbr->r_ctl.cur_rtt_send_time - bbr->r_ctl.bbr_ts_check_our_cts;
6192 	if (delta < bbr_min_usec_delta) {
6193 		/*
6194 		 * Have not seen a min amount of time
6195 		 * between our send times so we can
6196 		 * make a determination of the timestamp
6197 		 * yet.
6198 		 */
6199 		return;
6200 	}
6201 	peer_delta = bbr->r_ctl.last_inbound_ts - bbr->r_ctl.bbr_ts_check_tstmp;
6202 	if (peer_delta < bbr_min_peer_delta) {
6203 		/*
6204 		 * We may have enough in the form of
6205 		 * our delta but the peers number
6206 		 * has not changed that much. It could
6207 		 * be its clock ratio is such that
6208 		 * we need more data (10ms tick) or
6209 		 * there may be other compression scenarios
6210 		 * going on. In any event we need the
6211 		 * spread to be larger.
6212 		 */
6213 		return;
6214 	}
6215 	/* Ok lets first see which way our delta is going */
6216 	if (peer_delta > delta) {
6217 		/* Very unlikely, the peer without
6218 		 * compensation shows that it saw
6219 		 * the two sends arrive further apart
6220 		 * then we saw then in micro-seconds.
6221 		 */
6222 		if (peer_delta < (delta + ((delta * (uint64_t)1000)/ (uint64_t)bbr_delta_percent))) {
6223 			/* well it looks like the peer is a micro-second clock. */
6224 			bbr->rc_ts_clock_set = 1;
6225 			bbr->r_ctl.bbr_peer_tsratio = 1;
6226 		} else {
6227 			bbr->rc_ts_cant_be_used = 1;
6228 			bbr->rc_ts_clock_set = 1;
6229 		}
6230 		return;
6231 	}
6232 	/* Ok we know that the peer_delta is smaller than our send distance */
6233 	bbr->rc_ts_clock_set = 1;
6234 	/* First question is it within the percentage that they are using usec time? */
6235 	delta_up = (peer_delta * 1000) / (uint64_t)bbr_delta_percent;
6236 	if ((peer_delta + delta_up) >= delta) {
6237 		/* Its a usec clock */
6238 		bbr->r_ctl.bbr_peer_tsratio = 1;
6239 		bbr_log_tstmp_validation(bbr, peer_delta, delta);
6240 		return;
6241 	}
6242 	/* Ok if not usec, what about 10usec (though unlikely)? */
6243 	delta_up = (peer_delta * 1000 * 10) / (uint64_t)bbr_delta_percent;
6244 	if (((peer_delta * 10) + delta_up) >= delta) {
6245 		bbr->r_ctl.bbr_peer_tsratio = 10;
6246 		bbr_log_tstmp_validation(bbr, peer_delta, delta);
6247 		return;
6248 	}
6249 	/* And what about 100usec (though again unlikely)? */
6250 	delta_up = (peer_delta * 1000 * 100) / (uint64_t)bbr_delta_percent;
6251 	if (((peer_delta * 100) + delta_up) >= delta) {
6252 		bbr->r_ctl.bbr_peer_tsratio = 100;
6253 		bbr_log_tstmp_validation(bbr, peer_delta, delta);
6254 		return;
6255 	}
6256 	/* And how about 1 msec (the most likely one)? */
6257 	delta_up = (peer_delta * 1000 * 1000) / (uint64_t)bbr_delta_percent;
6258 	if (((peer_delta * 1000) + delta_up) >= delta) {
6259 		bbr->r_ctl.bbr_peer_tsratio = 1000;
6260 		bbr_log_tstmp_validation(bbr, peer_delta, delta);
6261 		return;
6262 	}
6263 	/* Ok if not msec could it be 10 msec? */
6264 	delta_up = (peer_delta * 1000 * 10000) / (uint64_t)bbr_delta_percent;
6265 	if (((peer_delta * 10000) + delta_up) >= delta) {
6266 		bbr->r_ctl.bbr_peer_tsratio = 10000;
6267 		return;
6268 	}
6269 	/* If we fall down here the clock tick so slowly we can't use it */
6270 	bbr->rc_ts_cant_be_used = 1;
6271 	bbr->r_ctl.bbr_peer_tsratio = 0;
6272 	bbr_log_tstmp_validation(bbr, peer_delta, delta);
6273 }
6274 
6275 /*
6276  * Collect new round-trip time estimate
6277  * and update averages and current timeout.
6278  */
6279 static void
6280 tcp_bbr_xmit_timer_commit(struct tcp_bbr *bbr, struct tcpcb *tp, uint32_t cts)
6281 {
6282 	int32_t delta;
6283 	uint32_t rtt, tsin;
6284 	int32_t rtt_ticks;
6285 
6286 	if (bbr->rtt_valid == 0)
6287 		/* No valid sample */
6288 		return;
6289 
6290 	rtt = bbr->r_ctl.cur_rtt;
6291 	tsin = bbr->r_ctl.ts_in;
6292 	if (bbr->rc_prtt_set_ts) {
6293 		/*
6294 		 * We are to force feed the rttProp filter due
6295 		 * to an entry into PROBE_RTT. This assures
6296 		 * that the times are sync'd between when we
6297 		 * go into PROBE_RTT and the filter expiration.
6298 		 *
6299 		 * Google does not use a true filter, so they do
6300 		 * this implicitly since they only keep one value
6301 		 * and when they enter probe-rtt they update the
6302 		 * value to the newest rtt.
6303 		 */
6304 		uint32_t rtt_prop;
6305 
6306 		bbr->rc_prtt_set_ts = 0;
6307 		rtt_prop = get_filter_value_small(&bbr->r_ctl.rc_rttprop);
6308 		if (rtt > rtt_prop)
6309 			filter_increase_by_small(&bbr->r_ctl.rc_rttprop, (rtt - rtt_prop), cts);
6310 		else
6311 			apply_filter_min_small(&bbr->r_ctl.rc_rttprop, rtt, cts);
6312 	}
6313 	if (bbr->rc_ack_was_delayed)
6314 		rtt += bbr->r_ctl.rc_ack_hdwr_delay;
6315 
6316 	if (rtt < bbr->r_ctl.rc_lowest_rtt)
6317 		bbr->r_ctl.rc_lowest_rtt = rtt;
6318 	bbr_log_rtt_sample(bbr, rtt, tsin);
6319 	if (bbr->r_init_rtt) {
6320 		/*
6321 		 * The initial rtt is not-trusted, nuke it and lets get
6322 		 * our first valid measurement in.
6323 		 */
6324 		bbr->r_init_rtt = 0;
6325 		tp->t_srtt = 0;
6326 	}
6327 	if ((bbr->rc_ts_clock_set == 0) && bbr->rc_ts_valid) {
6328 		/*
6329 		 * So we have not yet figured out
6330 		 * what the peers TSTMP value is
6331 		 * in (most likely ms). We need a
6332 		 * series of cum-ack's to determine
6333 		 * this reliably.
6334 		 */
6335 		if (bbr->rc_ack_is_cumack) {
6336 			if (bbr->rc_ts_data_set) {
6337 				/* Lets attempt to determine the timestamp granularity. */
6338 				bbr_make_timestamp_determination(bbr);
6339 			} else {
6340 				bbr->rc_ts_data_set = 1;
6341 				bbr->r_ctl.bbr_ts_check_tstmp = bbr->r_ctl.last_inbound_ts;
6342 				bbr->r_ctl.bbr_ts_check_our_cts = bbr->r_ctl.cur_rtt_send_time;
6343 			}
6344 		} else {
6345 			/*
6346 			 * We have to have consecutive acks
6347 			 * reset any "filled" state to none.
6348 			 */
6349 			bbr->rc_ts_data_set = 0;
6350 		}
6351 	}
6352 	/* Round it up */
6353 	rtt_ticks = USEC_2_TICKS((rtt + (USECS_IN_MSEC - 1)));
6354 	if (rtt_ticks == 0)
6355 		rtt_ticks = 1;
6356 	if (tp->t_srtt != 0) {
6357 		/*
6358 		 * srtt is stored as fixed point with 5 bits after the
6359 		 * binary point (i.e., scaled by 8).  The following magic is
6360 		 * equivalent to the smoothing algorithm in rfc793 with an
6361 		 * alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed point).
6362 		 * Adjust rtt to origin 0.
6363 		 */
6364 
6365 		delta = ((rtt_ticks - 1) << TCP_DELTA_SHIFT)
6366 		    - (tp->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT));
6367 
6368 		tp->t_srtt += delta;
6369 		if (tp->t_srtt <= 0)
6370 			tp->t_srtt = 1;
6371 
6372 		/*
6373 		 * We accumulate a smoothed rtt variance (actually, a
6374 		 * smoothed mean difference), then set the retransmit timer
6375 		 * to smoothed rtt + 4 times the smoothed variance. rttvar
6376 		 * is stored as fixed point with 4 bits after the binary
6377 		 * point (scaled by 16).  The following is equivalent to
6378 		 * rfc793 smoothing with an alpha of .75 (rttvar =
6379 		 * rttvar*3/4 + |delta| / 4).  This replaces rfc793's
6380 		 * wired-in beta.
6381 		 */
6382 		if (delta < 0)
6383 			delta = -delta;
6384 		delta -= tp->t_rttvar >> (TCP_RTTVAR_SHIFT - TCP_DELTA_SHIFT);
6385 		tp->t_rttvar += delta;
6386 		if (tp->t_rttvar <= 0)
6387 			tp->t_rttvar = 1;
6388 		if (tp->t_rttbest > tp->t_srtt + tp->t_rttvar)
6389 			tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
6390 	} else {
6391 		/*
6392 		 * No rtt measurement yet - use the unsmoothed rtt. Set the
6393 		 * variance to half the rtt (so our first retransmit happens
6394 		 * at 3*rtt).
6395 		 */
6396 		tp->t_srtt = rtt_ticks << TCP_RTT_SHIFT;
6397 		tp->t_rttvar = rtt_ticks << (TCP_RTTVAR_SHIFT - 1);
6398 		tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
6399 	}
6400 	KMOD_TCPSTAT_INC(tcps_rttupdated);
6401 	tp->t_rttupdated++;
6402 #ifdef STATS
6403 	stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RTT, imax(0, rtt_ticks));
6404 #endif
6405 	/*
6406 	 * the retransmit should happen at rtt + 4 * rttvar. Because of the
6407 	 * way we do the smoothing, srtt and rttvar will each average +1/2
6408 	 * tick of bias.  When we compute the retransmit timer, we want 1/2
6409 	 * tick of rounding and 1 extra tick because of +-1/2 tick
6410 	 * uncertainty in the firing of the timer.  The bias will give us
6411 	 * exactly the 1.5 tick we need.  But, because the bias is
6412 	 * statistical, we have to test that we don't drop below the minimum
6413 	 * feasible timer (which is 2 ticks).
6414 	 */
6415 	TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
6416 	    max(MSEC_2_TICKS(bbr->r_ctl.rc_min_rto_ms), rtt_ticks + 2),
6417 	    MSEC_2_TICKS(((uint32_t)bbr->rc_max_rto_sec) * 1000));
6418 
6419 	/*
6420 	 * We received an ack for a packet that wasn't retransmitted; it is
6421 	 * probably safe to discard any error indications we've received
6422 	 * recently.  This isn't quite right, but close enough for now (a
6423 	 * route might have failed after we sent a segment, and the return
6424 	 * path might not be symmetrical).
6425 	 */
6426 	tp->t_softerror = 0;
6427 	rtt = (TICKS_2_USEC(bbr->rc_tp->t_srtt) >> TCP_RTT_SHIFT);
6428 	if (bbr->r_ctl.bbr_smallest_srtt_this_state > rtt)
6429 		bbr->r_ctl.bbr_smallest_srtt_this_state = rtt;
6430 }
6431 
6432 static void
6433 bbr_earlier_retran(struct tcpcb *tp, struct tcp_bbr *bbr, struct bbr_sendmap *rsm,
6434 		   uint32_t t, uint32_t cts, int ack_type)
6435 {
6436 	/*
6437 	 * For this RSM, we acknowledged the data from a previous
6438 	 * transmission, not the last one we made. This means we did a false
6439 	 * retransmit.
6440 	 */
6441 	if (rsm->r_flags & BBR_HAS_FIN) {
6442 		/*
6443 		 * The sending of the FIN often is multiple sent when we
6444 		 * have everything outstanding ack'd. We ignore this case
6445 		 * since its over now.
6446 		 */
6447 		return;
6448 	}
6449 	if (rsm->r_flags & BBR_TLP) {
6450 		/*
6451 		 * We expect TLP's to have this occur often
6452 		 */
6453 		bbr->rc_tlp_rtx_out = 0;
6454 		return;
6455 	}
6456 	if (ack_type != BBR_CUM_ACKED) {
6457 		/*
6458 		 * If it was not a cum-ack we
6459 		 * don't really know for sure since
6460 		 * the timestamp could be from some
6461 		 * other transmission.
6462 		 */
6463 		return;
6464 	}
6465 
6466 	if (rsm->r_flags & BBR_WAS_SACKPASS) {
6467 		/*
6468 		 * We retransmitted based on a sack and the earlier
6469 		 * retransmission ack'd it - re-ordering is occuring.
6470 		 */
6471 		BBR_STAT_INC(bbr_reorder_seen);
6472 		bbr->r_ctl.rc_reorder_ts = cts;
6473 	}
6474 	/* Back down the loss count */
6475 	if (rsm->r_flags & BBR_MARKED_LOST) {
6476 		bbr->r_ctl.rc_lost -= rsm->r_end - rsm->r_start;
6477 		bbr->r_ctl.rc_lost_bytes -= rsm->r_end - rsm->r_start;
6478 		rsm->r_flags &= ~BBR_MARKED_LOST;
6479 		if (SEQ_GT(bbr->r_ctl.rc_lt_lost, bbr->r_ctl.rc_lost))
6480 			/* LT sampling also needs adjustment */
6481 			bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
6482 	}
6483 	/***** RRS HERE ************************/
6484 	/* Do we need to do this???            */
6485 	/* bbr_reset_lt_bw_sampling(bbr, cts); */
6486 	/***** RRS HERE ************************/
6487 	BBR_STAT_INC(bbr_badfr);
6488 	BBR_STAT_ADD(bbr_badfr_bytes, (rsm->r_end - rsm->r_start));
6489 }
6490 
6491 static void
6492 bbr_set_reduced_rtt(struct tcp_bbr *bbr, uint32_t cts, uint32_t line)
6493 {
6494 	bbr->r_ctl.rc_rtt_shrinks = cts;
6495 	if (bbr_can_force_probertt &&
6496 	    (TSTMP_GT(cts, bbr->r_ctl.last_in_probertt)) &&
6497 	    ((cts - bbr->r_ctl.last_in_probertt) > bbr->r_ctl.rc_probertt_int)) {
6498 		/*
6499 		 * We should enter probe-rtt its been too long
6500 		 * since we have been there.
6501 		 */
6502 		bbr_enter_probe_rtt(bbr, cts, __LINE__);
6503 	} else
6504 		bbr_check_probe_rtt_limits(bbr, cts);
6505 }
6506 
6507 static void
6508 tcp_bbr_commit_bw(struct tcp_bbr *bbr, uint32_t cts)
6509 {
6510 	uint64_t orig_bw;
6511 
6512 	if (bbr->r_ctl.rc_bbr_cur_del_rate == 0) {
6513 		/* We never apply a zero measurment */
6514 		bbr_log_type_bbrupd(bbr, 20, cts, 0, 0,
6515 				    0, 0, 0, 0, 0, 0);
6516 		return;
6517 	}
6518 	if (bbr->r_ctl.r_measurement_count < 0xffffffff)
6519 		bbr->r_ctl.r_measurement_count++;
6520 	orig_bw = get_filter_value(&bbr->r_ctl.rc_delrate);
6521 	apply_filter_max(&bbr->r_ctl.rc_delrate, bbr->r_ctl.rc_bbr_cur_del_rate, bbr->r_ctl.rc_pkt_epoch);
6522 	bbr_log_type_bbrupd(bbr, 21, cts, (uint32_t)orig_bw,
6523 			    (uint32_t)get_filter_value(&bbr->r_ctl.rc_delrate),
6524 			    0, 0, 0, 0, 0, 0);
6525 	if (orig_bw &&
6526 	    (orig_bw != get_filter_value(&bbr->r_ctl.rc_delrate))) {
6527 		if (bbr->bbr_hdrw_pacing) {
6528 			/*
6529 			 * Apply a new rate to the hardware
6530 			 * possibly.
6531 			 */
6532 			bbr_update_hardware_pacing_rate(bbr, cts);
6533 		}
6534 		bbr_set_state_target(bbr, __LINE__);
6535 		tcp_bbr_tso_size_check(bbr, cts);
6536 		if (bbr->r_recovery_bw)  {
6537 			bbr_setup_red_bw(bbr, cts);
6538 			bbr_log_type_bw_reduce(bbr, BBR_RED_BW_USELRBW);
6539 		}
6540 	} else if ((orig_bw == 0) && get_filter_value(&bbr->r_ctl.rc_delrate))
6541 		tcp_bbr_tso_size_check(bbr, cts);
6542 }
6543 
6544 static void
6545 bbr_nf_measurement(struct tcp_bbr *bbr, struct bbr_sendmap *rsm, uint32_t rtt, uint32_t cts)
6546 {
6547 	if (bbr->rc_in_persist == 0) {
6548 		/* We log only when not in persist */
6549 		/* Translate to a Bytes Per Second */
6550 		uint64_t tim, bw, ts_diff, ts_bw;
6551 		uint32_t upper, lower, delivered;
6552 
6553 		if (TSTMP_GT(bbr->r_ctl.rc_del_time, rsm->r_del_time))
6554 			tim = (uint64_t)(bbr->r_ctl.rc_del_time - rsm->r_del_time);
6555 		else
6556 			tim = 1;
6557 		/*
6558 		 * Now that we have processed the tim (skipping the sample
6559 		 * or possibly updating the time, go ahead and
6560 		 * calculate the cdr.
6561 		 */
6562 		delivered = (bbr->r_ctl.rc_delivered - rsm->r_delivered);
6563 		bw = (uint64_t)delivered;
6564 		bw *= (uint64_t)USECS_IN_SECOND;
6565 		bw /= tim;
6566 		if (bw == 0) {
6567 			/* We must have a calculatable amount */
6568 			return;
6569 		}
6570 		upper = (bw >> 32) & 0x00000000ffffffff;
6571 		lower = bw & 0x00000000ffffffff;
6572 		/*
6573 		 * If we are using this b/w shove it in now so we
6574 		 * can see in the trace viewer if it gets over-ridden.
6575 		 */
6576 		if (rsm->r_ts_valid &&
6577 		    bbr->rc_ts_valid &&
6578 		    bbr->rc_ts_clock_set &&
6579 		    (bbr->rc_ts_cant_be_used == 0) &&
6580 		    bbr->rc_use_ts_limit) {
6581 			ts_diff = max((bbr->r_ctl.last_inbound_ts - rsm->r_del_ack_ts), 1);
6582 			ts_diff *= bbr->r_ctl.bbr_peer_tsratio;
6583 			if ((delivered == 0) ||
6584 			    (rtt < 1000)) {
6585 				/* Can't use the ts */
6586 				bbr_log_type_bbrupd(bbr, 61, cts,
6587 						    ts_diff,
6588 						    bbr->r_ctl.last_inbound_ts,
6589 						    rsm->r_del_ack_ts, 0,
6590 						    0, 0, 0, delivered);
6591 			} else {
6592 				ts_bw = (uint64_t)delivered;
6593 				ts_bw *= (uint64_t)USECS_IN_SECOND;
6594 				ts_bw /= ts_diff;
6595 				bbr_log_type_bbrupd(bbr, 62, cts,
6596 						    (ts_bw >> 32),
6597 						    (ts_bw & 0xffffffff), 0, 0,
6598 						    0, 0, ts_diff, delivered);
6599 				if ((bbr->ts_can_raise) &&
6600 				    (ts_bw > bw)) {
6601 					bbr_log_type_bbrupd(bbr, 8, cts,
6602 							    delivered,
6603 							    ts_diff,
6604 							    (bw >> 32),
6605 							    (bw & 0x00000000ffffffff),
6606 							    0, 0, 0, 0);
6607 					bw = ts_bw;
6608 				} else if (ts_bw && (ts_bw < bw)) {
6609 					bbr_log_type_bbrupd(bbr, 7, cts,
6610 							    delivered,
6611 							    ts_diff,
6612 							    (bw >> 32),
6613 							    (bw & 0x00000000ffffffff),
6614 							    0, 0, 0, 0);
6615 					bw = ts_bw;
6616 				}
6617 			}
6618 		}
6619 		if (rsm->r_first_sent_time &&
6620 		    TSTMP_GT(rsm->r_tim_lastsent[(rsm->r_rtr_cnt -1)],rsm->r_first_sent_time)) {
6621 			uint64_t sbw, sti;
6622 			/*
6623 			 * We use what was in flight at the time of our
6624 			 * send  and the size of this send to figure
6625 			 * out what we have been sending at (amount).
6626 			 * For the time we take from the time of
6627 			 * the send of the first send outstanding
6628 			 * until this send plus this sends pacing
6629 			 * time. This gives us a good calculation
6630 			 * as to the rate we have been sending at.
6631 			 */
6632 
6633 			sbw = (uint64_t)(rsm->r_flight_at_send);
6634 			sbw *= (uint64_t)USECS_IN_SECOND;
6635 			sti = rsm->r_tim_lastsent[(rsm->r_rtr_cnt -1)] - rsm->r_first_sent_time;
6636 			sti += rsm->r_pacing_delay;
6637 			sbw /= sti;
6638 			if (sbw < bw) {
6639 				bbr_log_type_bbrupd(bbr, 6, cts,
6640 						    delivered,
6641 						    (uint32_t)sti,
6642 						    (bw >> 32),
6643 						    (uint32_t)bw,
6644 						    rsm->r_first_sent_time, 0, (sbw >> 32),
6645 						    (uint32_t)sbw);
6646 				bw = sbw;
6647 			}
6648 		}
6649 		/* Use the google algorithm for b/w measurements */
6650 		bbr->r_ctl.rc_bbr_cur_del_rate = bw;
6651 		if ((rsm->r_app_limited == 0) ||
6652 		    (bw > get_filter_value(&bbr->r_ctl.rc_delrate))) {
6653 			tcp_bbr_commit_bw(bbr, cts);
6654 			bbr_log_type_bbrupd(bbr, 10, cts, (uint32_t)tim, delivered,
6655 					    0, 0, 0, 0,  bbr->r_ctl.rc_del_time,  rsm->r_del_time);
6656 		}
6657 	}
6658 }
6659 
6660 static void
6661 bbr_google_measurement(struct tcp_bbr *bbr, struct bbr_sendmap *rsm, uint32_t rtt, uint32_t cts)
6662 {
6663 	if (bbr->rc_in_persist == 0) {
6664 		/* We log only when not in persist */
6665 		/* Translate to a Bytes Per Second */
6666 		uint64_t tim, bw;
6667 		uint32_t upper, lower, delivered;
6668 		int no_apply = 0;
6669 
6670 		if (TSTMP_GT(bbr->r_ctl.rc_del_time, rsm->r_del_time))
6671 			tim = (uint64_t)(bbr->r_ctl.rc_del_time - rsm->r_del_time);
6672 		else
6673 			tim = 1;
6674 		/*
6675 		 * Now that we have processed the tim (skipping the sample
6676 		 * or possibly updating the time, go ahead and
6677 		 * calculate the cdr.
6678 		 */
6679 		delivered = (bbr->r_ctl.rc_delivered - rsm->r_delivered);
6680 		bw = (uint64_t)delivered;
6681 		bw *= (uint64_t)USECS_IN_SECOND;
6682 		bw /= tim;
6683 		if (tim < bbr->r_ctl.rc_lowest_rtt) {
6684 			bbr_log_type_bbrupd(bbr, 99, cts, (uint32_t)tim, delivered,
6685 					    tim, bbr->r_ctl.rc_lowest_rtt, 0, 0, 0, 0);
6686 
6687 			no_apply = 1;
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 		bbr->r_ctl.rc_bbr_cur_del_rate = bw;
6696 		/* Gate by the sending rate */
6697 		if (rsm->r_first_sent_time &&
6698 		    TSTMP_GT(rsm->r_tim_lastsent[(rsm->r_rtr_cnt -1)],rsm->r_first_sent_time)) {
6699 			uint64_t sbw, sti;
6700 			/*
6701 			 * We use what was in flight at the time of our
6702 			 * send  and the size of this send to figure
6703 			 * out what we have been sending at (amount).
6704 			 * For the time we take from the time of
6705 			 * the send of the first send outstanding
6706 			 * until this send plus this sends pacing
6707 			 * time. This gives us a good calculation
6708 			 * as to the rate we have been sending at.
6709 			 */
6710 
6711 			sbw = (uint64_t)(rsm->r_flight_at_send);
6712 			sbw *= (uint64_t)USECS_IN_SECOND;
6713 			sti = rsm->r_tim_lastsent[(rsm->r_rtr_cnt -1)] - rsm->r_first_sent_time;
6714 			sti += rsm->r_pacing_delay;
6715 			sbw /= sti;
6716 			if (sbw < bw) {
6717 				bbr_log_type_bbrupd(bbr, 6, cts,
6718 						    delivered,
6719 						    (uint32_t)sti,
6720 						    (bw >> 32),
6721 						    (uint32_t)bw,
6722 						    rsm->r_first_sent_time, 0, (sbw >> 32),
6723 						    (uint32_t)sbw);
6724 				bw = sbw;
6725 			}
6726 			if ((sti > tim) &&
6727 			    (sti < bbr->r_ctl.rc_lowest_rtt)) {
6728 				bbr_log_type_bbrupd(bbr, 99, cts, (uint32_t)tim, delivered,
6729 						    (uint32_t)sti, bbr->r_ctl.rc_lowest_rtt, 0, 0, 0, 0);
6730 				no_apply = 1;
6731 			} else
6732 				no_apply = 0;
6733 		}
6734 		bbr->r_ctl.rc_bbr_cur_del_rate = bw;
6735 		if ((no_apply == 0) &&
6736 		    ((rsm->r_app_limited == 0) ||
6737 		     (bw > get_filter_value(&bbr->r_ctl.rc_delrate)))) {
6738 			tcp_bbr_commit_bw(bbr, cts);
6739 			bbr_log_type_bbrupd(bbr, 10, cts, (uint32_t)tim, delivered,
6740 					    0, 0, 0, 0, bbr->r_ctl.rc_del_time,  rsm->r_del_time);
6741 		}
6742 	}
6743 }
6744 
6745 static void
6746 bbr_update_bbr_info(struct tcp_bbr *bbr, struct bbr_sendmap *rsm, uint32_t rtt, uint32_t cts, uint32_t tsin,
6747     uint32_t uts, int32_t match, uint32_t rsm_send_time, int32_t ack_type, struct tcpopt *to)
6748 {
6749 	uint64_t old_rttprop;
6750 
6751 	/* Update our delivery time and amount */
6752 	bbr->r_ctl.rc_delivered += (rsm->r_end - rsm->r_start);
6753 	bbr->r_ctl.rc_del_time = cts;
6754 	if (rtt == 0) {
6755 		/*
6756 		 * 0 means its a retransmit, for now we don't use these for
6757 		 * the rest of BBR.
6758 		 */
6759 		return;
6760 	}
6761 	if ((bbr->rc_use_google == 0) &&
6762 	    (match != BBR_RTT_BY_EXACTMATCH) &&
6763 	    (match != BBR_RTT_BY_TIMESTAMP)){
6764 		/*
6765 		 * We get a lot of rtt updates, lets not pay attention to
6766 		 * any that are not an exact match. That way we don't have
6767 		 * to worry about timestamps and the whole nonsense of
6768 		 * unsure if its a retransmission etc (if we ever had the
6769 		 * timestamp fixed to always have the last thing sent this
6770 		 * would not be a issue).
6771 		 */
6772 		return;
6773 	}
6774 	if ((bbr_no_retran && bbr->rc_use_google) &&
6775 	    (match != BBR_RTT_BY_EXACTMATCH) &&
6776 	    (match != BBR_RTT_BY_TIMESTAMP)){
6777 		/*
6778 		 * We only do measurements in google mode
6779 		 * with bbr_no_retran on for sure things.
6780 		 */
6781 		return;
6782 	}
6783 	/* Only update srtt if we know by exact match */
6784 	tcp_bbr_xmit_timer(bbr, rtt, rsm_send_time, rsm->r_start, tsin);
6785 	if (ack_type == BBR_CUM_ACKED)
6786 		bbr->rc_ack_is_cumack = 1;
6787 	else
6788 		bbr->rc_ack_is_cumack = 0;
6789 	old_rttprop = bbr_get_rtt(bbr, BBR_RTT_PROP);
6790         /*
6791 	 * Note the following code differs to the original
6792 	 * BBR spec. It calls for <= not <. However after a
6793 	 * long discussion in email with Neal, he acknowledged
6794 	 * that it should be < than so that we will have flows
6795 	 * going into probe-rtt (we were seeing cases where that
6796 	 * did not happen and caused ugly things to occur). We
6797 	 * have added this agreed upon fix to our code base.
6798 	 */
6799 	if (rtt < old_rttprop) {
6800 		/* Update when we last saw a rtt drop */
6801 		bbr_log_rtt_shrinks(bbr, cts, 0, rtt, __LINE__, BBR_RTTS_NEWRTT, 0);
6802 		bbr_set_reduced_rtt(bbr, cts, __LINE__);
6803 	}
6804 	bbr_log_type_bbrrttprop(bbr, rtt, (rsm ? rsm->r_end : 0), uts, cts,
6805 	    match, rsm->r_start, rsm->r_flags);
6806 	apply_filter_min_small(&bbr->r_ctl.rc_rttprop, rtt, cts);
6807 	if (old_rttprop != bbr_get_rtt(bbr, BBR_RTT_PROP)) {
6808 		/*
6809 		 * The RTT-prop moved, reset the target (may be a
6810 		 * nop for some states).
6811 		 */
6812 		bbr_set_state_target(bbr, __LINE__);
6813 		if (bbr->rc_bbr_state == BBR_STATE_PROBE_RTT)
6814 			bbr_log_rtt_shrinks(bbr, cts, 0, 0,
6815 					    __LINE__, BBR_RTTS_NEW_TARGET, 0);
6816 		else if (old_rttprop < bbr_get_rtt(bbr, BBR_RTT_PROP))
6817 			/* It went up */
6818 			bbr_check_probe_rtt_limits(bbr, cts);
6819 	}
6820 	if ((bbr->rc_use_google == 0) &&
6821 	    (match == BBR_RTT_BY_TIMESTAMP)) {
6822 		/*
6823 		 * We don't do b/w update with
6824 		 * these since they are not really
6825 		 * reliable.
6826 		 */
6827 		return;
6828 	}
6829 	if (bbr->r_ctl.r_app_limited_until &&
6830 	    (bbr->r_ctl.rc_delivered >= bbr->r_ctl.r_app_limited_until)) {
6831 		/* We are no longer app-limited */
6832 		bbr->r_ctl.r_app_limited_until = 0;
6833 	}
6834 	if (bbr->rc_use_google) {
6835 		bbr_google_measurement(bbr, rsm, rtt, cts);
6836 	} else {
6837 		bbr_nf_measurement(bbr, rsm, rtt, cts);
6838 	}
6839 }
6840 
6841 /*
6842  * Convert a timestamp that the main stack
6843  * uses (milliseconds) into one that bbr uses
6844  * (microseconds). Return that converted timestamp.
6845  */
6846 static uint32_t
6847 bbr_ts_convert(uint32_t cts) {
6848 	uint32_t sec, msec;
6849 
6850 	sec = cts / MS_IN_USEC;
6851 	msec = cts - (MS_IN_USEC * sec);
6852 	return ((sec * USECS_IN_SECOND) + (msec * MS_IN_USEC));
6853 }
6854 
6855 /*
6856  * Return 0 if we did not update the RTT time, return
6857  * 1 if we did.
6858  */
6859 static int
6860 bbr_update_rtt(struct tcpcb *tp, struct tcp_bbr *bbr,
6861     struct bbr_sendmap *rsm, struct tcpopt *to, uint32_t cts, int32_t ack_type, uint32_t th_ack)
6862 {
6863 	int32_t i;
6864 	uint32_t t, uts = 0;
6865 
6866 	if ((rsm->r_flags & BBR_ACKED) ||
6867 	    (rsm->r_flags & BBR_WAS_RENEGED) ||
6868 	    (rsm->r_flags & BBR_RXT_CLEARED)) {
6869 		/* Already done */
6870 		return (0);
6871 	}
6872 	if (rsm->r_rtr_cnt == 1) {
6873 		/*
6874 		 * Only one transmit. Hopefully the normal case.
6875 		 */
6876 		if (TSTMP_GT(cts, rsm->r_tim_lastsent[0]))
6877 			t = cts - rsm->r_tim_lastsent[0];
6878 		else
6879 			t = 1;
6880 		if ((int)t <= 0)
6881 			t = 1;
6882 		bbr->r_ctl.rc_last_rtt = t;
6883 		bbr_update_bbr_info(bbr, rsm, t, cts, to->to_tsecr, 0,
6884 				    BBR_RTT_BY_EXACTMATCH, rsm->r_tim_lastsent[0], ack_type, to);
6885 		return (1);
6886 	}
6887 	/* Convert to usecs */
6888 	if ((bbr_can_use_ts_for_rtt == 1) &&
6889 	    (bbr->rc_use_google == 1) &&
6890 	    (ack_type == BBR_CUM_ACKED) &&
6891 	    (to->to_flags & TOF_TS) &&
6892 	    (to->to_tsecr != 0)) {
6893 		t = tcp_tv_to_mssectick(&bbr->rc_tv) - to->to_tsecr;
6894 		if (t < 1)
6895 			t = 1;
6896 		t *= MS_IN_USEC;
6897 		bbr_update_bbr_info(bbr, rsm, t, cts, to->to_tsecr, 0,
6898 				    BBR_RTT_BY_TIMESTAMP,
6899 				    rsm->r_tim_lastsent[(rsm->r_rtr_cnt-1)],
6900 				    ack_type, to);
6901 		return (1);
6902 	}
6903 	uts = bbr_ts_convert(to->to_tsecr);
6904 	if ((to->to_flags & TOF_TS) &&
6905 	    (to->to_tsecr != 0) &&
6906 	    (ack_type == BBR_CUM_ACKED) &&
6907 	    ((rsm->r_flags & BBR_OVERMAX) == 0)) {
6908 		/*
6909 		 * Now which timestamp does it match? In this block the ACK
6910 		 * may be coming from a previous transmission.
6911 		 */
6912 		uint32_t fudge;
6913 
6914 		fudge = BBR_TIMER_FUDGE;
6915 		for (i = 0; i < rsm->r_rtr_cnt; i++) {
6916 			if ((SEQ_GEQ(uts, (rsm->r_tim_lastsent[i] - fudge))) &&
6917 			    (SEQ_LEQ(uts, (rsm->r_tim_lastsent[i] + fudge)))) {
6918 				if (TSTMP_GT(cts, rsm->r_tim_lastsent[i]))
6919 					t = cts - rsm->r_tim_lastsent[i];
6920 				else
6921 					t = 1;
6922 				if ((int)t <= 0)
6923 					t = 1;
6924 				bbr->r_ctl.rc_last_rtt = t;
6925 				bbr_update_bbr_info(bbr, rsm, t, cts, to->to_tsecr, uts, BBR_RTT_BY_TSMATCHING,
6926 						    rsm->r_tim_lastsent[i], ack_type, to);
6927 				if ((i + 1) < rsm->r_rtr_cnt) {
6928 					/* Likely */
6929 					bbr_earlier_retran(tp, bbr, rsm, t, cts, ack_type);
6930 				} else if (rsm->r_flags & BBR_TLP) {
6931 					bbr->rc_tlp_rtx_out = 0;
6932 				}
6933 				return (1);
6934 			}
6935 		}
6936 		/* Fall through if we can't find a matching timestamp */
6937 	}
6938 	/*
6939 	 * Ok its a SACK block that we retransmitted. or a windows
6940 	 * machine without timestamps. We can tell nothing from the
6941 	 * time-stamp since its not there or the time the peer last
6942 	 * recieved a segment that moved forward its cum-ack point.
6943 	 *
6944 	 * Lets look at the last retransmit and see what we can tell
6945 	 * (with BBR for space we only keep 2 note we have to keep
6946 	 * at least 2 so the map can not be condensed more).
6947 	 */
6948 	i = rsm->r_rtr_cnt - 1;
6949 	if (TSTMP_GT(cts, rsm->r_tim_lastsent[i]))
6950 		t = cts - rsm->r_tim_lastsent[i];
6951 	else
6952 		goto not_sure;
6953 	if (t < bbr->r_ctl.rc_lowest_rtt) {
6954 		/*
6955 		 * We retransmitted and the ack came back in less
6956 		 * than the smallest rtt we have observed in the
6957 		 * windowed rtt. We most likey did an improper
6958 		 * retransmit as outlined in 4.2 Step 3 point 2 in
6959 		 * the rack-draft.
6960 		 *
6961 		 * Use the prior transmission to update all the
6962 		 * information as long as there is only one prior
6963 		 * transmission.
6964 		 */
6965 		if ((rsm->r_flags & BBR_OVERMAX) == 0) {
6966 #ifdef BBR_INVARIANTS
6967 			if (rsm->r_rtr_cnt == 1)
6968 				panic("rsm:%p bbr:%p rsm has overmax and only 1 retranmit flags:%x?", rsm, bbr, rsm->r_flags);
6969 #endif
6970 			i = rsm->r_rtr_cnt - 2;
6971 			if (TSTMP_GT(cts, rsm->r_tim_lastsent[i]))
6972 				t = cts - rsm->r_tim_lastsent[i];
6973 			else
6974 				t = 1;
6975 			bbr_update_bbr_info(bbr, rsm, t, cts, to->to_tsecr, uts, BBR_RTT_BY_EARLIER_RET,
6976 					    rsm->r_tim_lastsent[i], ack_type, to);
6977 			bbr_earlier_retran(tp, bbr, rsm, t, cts, ack_type);
6978 		} else {
6979 			/*
6980 			 * Too many prior transmissions, just
6981 			 * updated BBR delivered
6982 			 */
6983 not_sure:
6984 			bbr_update_bbr_info(bbr, rsm, 0, cts, to->to_tsecr, uts,
6985 					    BBR_RTT_BY_SOME_RETRAN, 0, ack_type, to);
6986 		}
6987 	} else {
6988 		/*
6989 		 * We retransmitted it and the retransmit did the
6990 		 * job.
6991 		 */
6992 		if (rsm->r_flags & BBR_TLP)
6993 			bbr->rc_tlp_rtx_out = 0;
6994 		if ((rsm->r_flags & BBR_OVERMAX) == 0)
6995 			bbr_update_bbr_info(bbr, rsm, t, cts, to->to_tsecr, uts,
6996 					    BBR_RTT_BY_THIS_RETRAN, 0, ack_type, to);
6997 		else
6998 			bbr_update_bbr_info(bbr, rsm, 0, cts, to->to_tsecr, uts,
6999 					    BBR_RTT_BY_SOME_RETRAN, 0, ack_type, to);
7000 		return (1);
7001 	}
7002 	return (0);
7003 }
7004 
7005 /*
7006  * Mark the SACK_PASSED flag on all entries prior to rsm send wise.
7007  */
7008 static void
7009 bbr_log_sack_passed(struct tcpcb *tp,
7010     struct tcp_bbr *bbr, struct bbr_sendmap *rsm)
7011 {
7012 	struct bbr_sendmap *nrsm;
7013 
7014 	nrsm = rsm;
7015 	TAILQ_FOREACH_REVERSE_FROM(nrsm, &bbr->r_ctl.rc_tmap,
7016 	    bbr_head, r_tnext) {
7017 		if (nrsm == rsm) {
7018 			/* Skip orginal segment he is acked */
7019 			continue;
7020 		}
7021 		if (nrsm->r_flags & BBR_ACKED) {
7022 			/* Skip ack'd segments */
7023 			continue;
7024 		}
7025 		if (nrsm->r_flags & BBR_SACK_PASSED) {
7026 			/*
7027 			 * We found one that is already marked
7028 			 * passed, we have been here before and
7029 			 * so all others below this are marked.
7030 			 */
7031 			break;
7032 		}
7033 		BBR_STAT_INC(bbr_sack_passed);
7034 		nrsm->r_flags |= BBR_SACK_PASSED;
7035 		if (((nrsm->r_flags & BBR_MARKED_LOST) == 0) &&
7036 		    bbr_is_lost(bbr, nrsm, bbr->r_ctl.rc_rcvtime)) {
7037 			bbr->r_ctl.rc_lost += nrsm->r_end - nrsm->r_start;
7038 			bbr->r_ctl.rc_lost_bytes += nrsm->r_end - nrsm->r_start;
7039 			nrsm->r_flags |= BBR_MARKED_LOST;
7040 		}
7041 		nrsm->r_flags &= ~BBR_WAS_SACKPASS;
7042 	}
7043 }
7044 
7045 /*
7046  * Returns the number of bytes that were
7047  * newly ack'd by sack blocks.
7048  */
7049 static uint32_t
7050 bbr_proc_sack_blk(struct tcpcb *tp, struct tcp_bbr *bbr, struct sackblk *sack,
7051     struct tcpopt *to, struct bbr_sendmap **prsm, uint32_t cts)
7052 {
7053 	int32_t times = 0;
7054 	uint32_t start, end, maxseg, changed = 0;
7055 	struct bbr_sendmap *rsm, *nrsm;
7056 	int32_t used_ref = 1;
7057 	uint8_t went_back = 0, went_fwd = 0;
7058 
7059 	maxseg = tp->t_maxseg - bbr->rc_last_options;
7060 	start = sack->start;
7061 	end = sack->end;
7062 	rsm = *prsm;
7063 	if (rsm == NULL)
7064 		used_ref = 0;
7065 
7066 	/* Do we locate the block behind where we last were? */
7067 	if (rsm && SEQ_LT(start, rsm->r_start)) {
7068 		went_back = 1;
7069 		TAILQ_FOREACH_REVERSE_FROM(rsm, &bbr->r_ctl.rc_map, bbr_head, r_next) {
7070 			if (SEQ_GEQ(start, rsm->r_start) &&
7071 			    SEQ_LT(start, rsm->r_end)) {
7072 				goto do_rest_ofb;
7073 			}
7074 		}
7075 	}
7076 start_at_beginning:
7077 	went_fwd = 1;
7078 	/*
7079 	 * Ok lets locate the block where this guy is fwd from rsm (if its
7080 	 * set)
7081 	 */
7082 	TAILQ_FOREACH_FROM(rsm, &bbr->r_ctl.rc_map, r_next) {
7083 		if (SEQ_GEQ(start, rsm->r_start) &&
7084 		    SEQ_LT(start, rsm->r_end)) {
7085 			break;
7086 		}
7087 	}
7088 do_rest_ofb:
7089 	if (rsm == NULL) {
7090 		/*
7091 		 * This happens when we get duplicate sack blocks with the
7092 		 * same end. For example SACK 4: 100 SACK 3: 100 The sort
7093 		 * will not change there location so we would just start at
7094 		 * the end of the first one and get lost.
7095 		 */
7096 		if (tp->t_flags & TF_SENTFIN) {
7097 			/*
7098 			 * Check to see if we have not logged the FIN that
7099 			 * went out.
7100 			 */
7101 			nrsm = TAILQ_LAST_FAST(&bbr->r_ctl.rc_map, bbr_sendmap, r_next);
7102 			if (nrsm && (nrsm->r_end + 1) == tp->snd_max) {
7103 				/*
7104 				 * Ok we did not get the FIN logged.
7105 				 */
7106 				nrsm->r_end++;
7107 				rsm = nrsm;
7108 				goto do_rest_ofb;
7109 			}
7110 		}
7111 		if (times == 1) {
7112 #ifdef BBR_INVARIANTS
7113 			panic("tp:%p bbr:%p sack:%p to:%p prsm:%p",
7114 			    tp, bbr, sack, to, prsm);
7115 #else
7116 			goto out;
7117 #endif
7118 		}
7119 		times++;
7120 		BBR_STAT_INC(bbr_sack_proc_restart);
7121 		rsm = NULL;
7122 		goto start_at_beginning;
7123 	}
7124 	/* Ok we have an ACK for some piece of rsm */
7125 	if (rsm->r_start != start) {
7126 		/*
7127 		 * Need to split this in two pieces the before and after.
7128 		 */
7129 		if (bbr_sack_mergable(rsm, start, end))
7130 			nrsm = bbr_alloc_full_limit(bbr);
7131 		else
7132 			nrsm = bbr_alloc_limit(bbr, BBR_LIMIT_TYPE_SPLIT);
7133 		if (nrsm == NULL) {
7134 			/* We could not allocate ignore the sack */
7135 			struct sackblk blk;
7136 
7137 			blk.start = start;
7138 			blk.end = end;
7139 			sack_filter_reject(&bbr->r_ctl.bbr_sf, &blk);
7140 			goto out;
7141 		}
7142 		bbr_clone_rsm(bbr, nrsm, rsm, start);
7143 		TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_map, rsm, nrsm, r_next);
7144 		if (rsm->r_in_tmap) {
7145 			TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
7146 			nrsm->r_in_tmap = 1;
7147 		}
7148 		rsm->r_flags &= (~BBR_HAS_FIN);
7149 		rsm = nrsm;
7150 	}
7151 	if (SEQ_GEQ(end, rsm->r_end)) {
7152 		/*
7153 		 * The end of this block is either beyond this guy or right
7154 		 * at this guy.
7155 		 */
7156 		if ((rsm->r_flags & BBR_ACKED) == 0) {
7157 			bbr_update_rtt(tp, bbr, rsm, to, cts, BBR_SACKED, 0);
7158 			changed += (rsm->r_end - rsm->r_start);
7159 			bbr->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start);
7160 			bbr_log_sack_passed(tp, bbr, rsm);
7161 			if (rsm->r_flags & BBR_MARKED_LOST) {
7162 				bbr->r_ctl.rc_lost_bytes -= rsm->r_end - rsm->r_start;
7163 			}
7164 			/* Is Reordering occuring? */
7165 			if (rsm->r_flags & BBR_SACK_PASSED) {
7166 				BBR_STAT_INC(bbr_reorder_seen);
7167 				bbr->r_ctl.rc_reorder_ts = cts;
7168 				if (rsm->r_flags & BBR_MARKED_LOST) {
7169 					bbr->r_ctl.rc_lost -= rsm->r_end - rsm->r_start;
7170 					if (SEQ_GT(bbr->r_ctl.rc_lt_lost, bbr->r_ctl.rc_lost))
7171 						/* LT sampling also needs adjustment */
7172 						bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
7173 				}
7174 			}
7175 			rsm->r_flags |= BBR_ACKED;
7176 			rsm->r_flags &= ~(BBR_TLP|BBR_WAS_RENEGED|BBR_RXT_CLEARED|BBR_MARKED_LOST);
7177 			if (rsm->r_in_tmap) {
7178 				TAILQ_REMOVE(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
7179 				rsm->r_in_tmap = 0;
7180 			}
7181 		}
7182 		bbr_isit_a_pkt_epoch(bbr, cts, rsm, __LINE__, BBR_SACKED);
7183 		if (end == rsm->r_end) {
7184 			/* This block only - done */
7185 			goto out;
7186 		}
7187 		/* There is more not coverend by this rsm move on */
7188 		start = rsm->r_end;
7189 		nrsm = TAILQ_NEXT(rsm, r_next);
7190 		rsm = nrsm;
7191 		times = 0;
7192 		goto do_rest_ofb;
7193 	}
7194 	if (rsm->r_flags & BBR_ACKED) {
7195 		/* Been here done that */
7196 		goto out;
7197 	}
7198 	/* Ok we need to split off this one at the tail */
7199 	if (bbr_sack_mergable(rsm, start, end))
7200 		nrsm = bbr_alloc_full_limit(bbr);
7201 	else
7202 		nrsm = bbr_alloc_limit(bbr, BBR_LIMIT_TYPE_SPLIT);
7203 	if (nrsm == NULL) {
7204 		/* failed XXXrrs what can we do but loose the sack info? */
7205 		struct sackblk blk;
7206 
7207 		blk.start = start;
7208 		blk.end = end;
7209 		sack_filter_reject(&bbr->r_ctl.bbr_sf, &blk);
7210 		goto out;
7211 	}
7212 	/* Clone it */
7213 	bbr_clone_rsm(bbr, nrsm, rsm, end);
7214 	/* The sack block does not cover this guy fully */
7215 	rsm->r_flags &= (~BBR_HAS_FIN);
7216 	TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_map, rsm, nrsm, r_next);
7217 	if (rsm->r_in_tmap) {
7218 		TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
7219 		nrsm->r_in_tmap = 1;
7220 	}
7221 	nrsm->r_dupack = 0;
7222 	bbr_update_rtt(tp, bbr, rsm, to, cts, BBR_SACKED, 0);
7223 	bbr_isit_a_pkt_epoch(bbr, cts, rsm, __LINE__, BBR_SACKED);
7224 	changed += (rsm->r_end - rsm->r_start);
7225 	bbr->r_ctl.rc_sacked += (rsm->r_end - rsm->r_start);
7226 	bbr_log_sack_passed(tp, bbr, rsm);
7227 	/* Is Reordering occuring? */
7228 	if (rsm->r_flags & BBR_MARKED_LOST) {
7229 		bbr->r_ctl.rc_lost_bytes -= rsm->r_end - rsm->r_start;
7230 	}
7231 	if (rsm->r_flags & BBR_SACK_PASSED) {
7232 		BBR_STAT_INC(bbr_reorder_seen);
7233 		bbr->r_ctl.rc_reorder_ts = cts;
7234 		if (rsm->r_flags & BBR_MARKED_LOST) {
7235 			bbr->r_ctl.rc_lost -= rsm->r_end - rsm->r_start;
7236 			if (SEQ_GT(bbr->r_ctl.rc_lt_lost, bbr->r_ctl.rc_lost))
7237 				/* LT sampling also needs adjustment */
7238 				bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
7239 		}
7240 	}
7241 	rsm->r_flags &= ~(BBR_TLP|BBR_WAS_RENEGED|BBR_RXT_CLEARED|BBR_MARKED_LOST);
7242 	rsm->r_flags |= BBR_ACKED;
7243 	if (rsm->r_in_tmap) {
7244 		TAILQ_REMOVE(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
7245 		rsm->r_in_tmap = 0;
7246 	}
7247 out:
7248 	if (rsm && (rsm->r_flags & BBR_ACKED)) {
7249 		/*
7250 		 * Now can we merge this newly acked
7251 		 * block with either the previous or
7252 		 * next block?
7253 		 */
7254 		nrsm = TAILQ_NEXT(rsm, r_next);
7255 		if (nrsm &&
7256 		    (nrsm->r_flags & BBR_ACKED)) {
7257 			/* yep this and next can be merged */
7258 			rsm = bbr_merge_rsm(bbr, rsm, nrsm);
7259 		}
7260 		/* Now what about the previous? */
7261 		nrsm = TAILQ_PREV(rsm, bbr_head, r_next);
7262 		if (nrsm &&
7263 		    (nrsm->r_flags & BBR_ACKED)) {
7264 			/* yep the previous and this can be merged */
7265 			rsm = bbr_merge_rsm(bbr, nrsm, rsm);
7266 		}
7267 	}
7268 	if (used_ref == 0) {
7269 		BBR_STAT_INC(bbr_sack_proc_all);
7270 	} else {
7271 		BBR_STAT_INC(bbr_sack_proc_short);
7272 	}
7273 	if (went_fwd && went_back) {
7274 		BBR_STAT_INC(bbr_sack_search_both);
7275 	} else if (went_fwd) {
7276 		BBR_STAT_INC(bbr_sack_search_fwd);
7277 	} else if (went_back) {
7278 		BBR_STAT_INC(bbr_sack_search_back);
7279 	}
7280 	/* Save off where the next seq is */
7281 	if (rsm)
7282 		bbr->r_ctl.rc_sacklast = TAILQ_NEXT(rsm, r_next);
7283 	else
7284 		bbr->r_ctl.rc_sacklast = NULL;
7285 	*prsm = rsm;
7286 	return (changed);
7287 }
7288 
7289 static void inline
7290 bbr_peer_reneges(struct tcp_bbr *bbr, struct bbr_sendmap *rsm, tcp_seq th_ack)
7291 {
7292 	struct bbr_sendmap *tmap;
7293 
7294 	BBR_STAT_INC(bbr_reneges_seen);
7295 	tmap = NULL;
7296 	while (rsm && (rsm->r_flags & BBR_ACKED)) {
7297 		/* Its no longer sacked, mark it so */
7298 		uint32_t oflags;
7299 		bbr->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
7300 #ifdef BBR_INVARIANTS
7301 		if (rsm->r_in_tmap) {
7302 			panic("bbr:%p rsm:%p flags:0x%x in tmap?",
7303 			    bbr, rsm, rsm->r_flags);
7304 		}
7305 #endif
7306 		oflags = rsm->r_flags;
7307 		if (rsm->r_flags & BBR_MARKED_LOST) {
7308 			bbr->r_ctl.rc_lost -= rsm->r_end - rsm->r_start;
7309 			bbr->r_ctl.rc_lost_bytes -= rsm->r_end - rsm->r_start;
7310 			if (SEQ_GT(bbr->r_ctl.rc_lt_lost, bbr->r_ctl.rc_lost))
7311 				/* LT sampling also needs adjustment */
7312 				bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
7313 		}
7314 		rsm->r_flags &= ~(BBR_ACKED | BBR_SACK_PASSED | BBR_WAS_SACKPASS | BBR_MARKED_LOST);
7315 		rsm->r_flags |= BBR_WAS_RENEGED;
7316 		rsm->r_flags |= BBR_RXT_CLEARED;
7317 		bbr_log_type_rsmclear(bbr, bbr->r_ctl.rc_rcvtime, rsm, oflags, __LINE__);
7318 		/* Rebuild it into our tmap */
7319 		if (tmap == NULL) {
7320 			TAILQ_INSERT_HEAD(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
7321 			tmap = rsm;
7322 		} else {
7323 			TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, tmap, rsm, r_tnext);
7324 			tmap = rsm;
7325 		}
7326 		tmap->r_in_tmap = 1;
7327 		/*
7328 		 * XXXrrs Delivered? Should we do anything here?
7329 		 *
7330 		 * Of course we don't on a rxt timeout so maybe its ok that
7331 		 * we don't?
7332 		 *
7333 		 * For now lets not.
7334 		 */
7335 		rsm = TAILQ_NEXT(rsm, r_next);
7336 	}
7337 	/*
7338 	 * Now lets possibly clear the sack filter so we start recognizing
7339 	 * sacks that cover this area.
7340 	 */
7341 	sack_filter_clear(&bbr->r_ctl.bbr_sf, th_ack);
7342 }
7343 
7344 static void
7345 bbr_log_syn(struct tcpcb *tp, struct tcpopt *to)
7346 {
7347 	struct tcp_bbr *bbr;
7348 	struct bbr_sendmap *rsm;
7349 	uint32_t cts;
7350 
7351 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
7352 	cts = bbr->r_ctl.rc_rcvtime;
7353 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
7354 	if (rsm && (rsm->r_flags & BBR_HAS_SYN)) {
7355 		if ((rsm->r_end - rsm->r_start) <= 1) {
7356 			/* Log out the SYN completely */
7357 			bbr->r_ctl.rc_holes_rxt -= rsm->r_rtr_bytes;
7358 			rsm->r_rtr_bytes = 0;
7359 			TAILQ_REMOVE(&bbr->r_ctl.rc_map, rsm, r_next);
7360 			if (rsm->r_in_tmap) {
7361 				TAILQ_REMOVE(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
7362 				rsm->r_in_tmap = 0;
7363 			}
7364 			if (bbr->r_ctl.rc_next == rsm) {
7365 				/* scoot along the marker */
7366 				bbr->r_ctl.rc_next = TAILQ_FIRST(&bbr->r_ctl.rc_map);
7367 			}
7368 			if (to != NULL)
7369 				bbr_update_rtt(tp, bbr, rsm, to, cts, BBR_CUM_ACKED, 0);
7370 			bbr_free(bbr, rsm);
7371 		} else {
7372 			/* There is more (Fast open)? strip out SYN. */
7373 			rsm->r_flags &= ~BBR_HAS_SYN;
7374 			rsm->r_start++;
7375 		}
7376 	}
7377 }
7378 
7379 /*
7380  * Returns the number of bytes that were
7381  * acknowledged by SACK blocks.
7382  */
7383 
7384 static uint32_t
7385 bbr_log_ack(struct tcpcb *tp, struct tcpopt *to, struct tcphdr *th,
7386     uint32_t *prev_acked)
7387 {
7388 	uint32_t changed, last_seq, entered_recovery = 0;
7389 	struct tcp_bbr *bbr;
7390 	struct bbr_sendmap *rsm;
7391 	struct sackblk sack, sack_blocks[TCP_MAX_SACK + 1];
7392 	register uint32_t th_ack;
7393 	int32_t i, j, k, new_sb, num_sack_blks = 0;
7394 	uint32_t cts, acked, ack_point, sack_changed = 0;
7395 	uint32_t p_maxseg, maxseg, p_acked = 0;
7396 
7397 	INP_WLOCK_ASSERT(tp->t_inpcb);
7398 	if (th->th_flags & TH_RST) {
7399 		/* We don't log resets */
7400 		return (0);
7401 	}
7402 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
7403 	cts = bbr->r_ctl.rc_rcvtime;
7404 
7405 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
7406 	changed = 0;
7407 	maxseg = tp->t_maxseg - bbr->rc_last_options;
7408 	p_maxseg = min(bbr->r_ctl.rc_pace_max_segs, maxseg);
7409 	th_ack = th->th_ack;
7410 	if (SEQ_GT(th_ack, tp->snd_una)) {
7411 		acked = th_ack - tp->snd_una;
7412 		bbr_log_progress_event(bbr, tp, ticks, PROGRESS_UPDATE, __LINE__);
7413 		bbr->rc_tp->t_acktime = ticks;
7414 	} else
7415 		acked = 0;
7416 	if (SEQ_LEQ(th_ack, tp->snd_una)) {
7417 		/* Only sent here for sack processing */
7418 		goto proc_sack;
7419 	}
7420 	if (rsm && SEQ_GT(th_ack, rsm->r_start)) {
7421 		changed = th_ack - rsm->r_start;
7422 	} else if ((rsm == NULL) && ((th_ack - 1) == tp->iss)) {
7423 		/*
7424 		 * For the SYN incoming case we will not have called
7425 		 * tcp_output for the sending of the SYN, so there will be
7426 		 * no map. All other cases should probably be a panic.
7427 		 */
7428 		if ((to->to_flags & TOF_TS) && (to->to_tsecr != 0)) {
7429 			/*
7430 			 * We have a timestamp that can be used to generate
7431 			 * an initial RTT.
7432 			 */
7433 			uint32_t ts, now, rtt;
7434 
7435 			ts = bbr_ts_convert(to->to_tsecr);
7436 			now = bbr_ts_convert(tcp_tv_to_mssectick(&bbr->rc_tv));
7437 			rtt = now - ts;
7438 			if (rtt < 1)
7439 				rtt = 1;
7440 			bbr_log_type_bbrrttprop(bbr, rtt,
7441 						tp->iss, 0, cts,
7442 						BBR_RTT_BY_TIMESTAMP, tp->iss, 0);
7443 			apply_filter_min_small(&bbr->r_ctl.rc_rttprop, rtt, cts);
7444 			changed = 1;
7445 			bbr->r_wanted_output = 1;
7446 			goto out;
7447 		}
7448 		goto proc_sack;
7449 	} else if (rsm == NULL) {
7450 		goto out;
7451 	}
7452 	if (changed) {
7453 		/*
7454 		 * The ACK point is advancing to th_ack, we must drop off
7455 		 * the packets in the rack log and calculate any eligble
7456 		 * RTT's.
7457 		 */
7458 		bbr->r_wanted_output = 1;
7459 more:
7460 		if (rsm == NULL) {
7461 			if (tp->t_flags & TF_SENTFIN) {
7462 				/* if we send a FIN we will not hav a map */
7463 				goto proc_sack;
7464 			}
7465 #ifdef BBR_INVARIANTS
7466 			panic("No rack map tp:%p for th:%p state:%d bbr:%p snd_una:%u snd_max:%u chg:%d\n",
7467 			    tp,
7468 			    th, tp->t_state, bbr,
7469 			    tp->snd_una, tp->snd_max, changed);
7470 #endif
7471 			goto proc_sack;
7472 		}
7473 	}
7474 	if (SEQ_LT(th_ack, rsm->r_start)) {
7475 		/* Huh map is missing this */
7476 #ifdef BBR_INVARIANTS
7477 		printf("Rack map starts at r_start:%u for th_ack:%u huh? ts:%d rs:%d bbr:%p\n",
7478 		    rsm->r_start,
7479 		    th_ack, tp->t_state,
7480 		    bbr->r_state, bbr);
7481 		panic("th-ack is bad bbr:%p tp:%p", bbr, tp);
7482 #endif
7483 		goto proc_sack;
7484 	} else if (th_ack == rsm->r_start) {
7485 		/* None here to ack */
7486 		goto proc_sack;
7487 	}
7488 	/*
7489 	 * Clear the dup ack counter, it will
7490 	 * either be freed or if there is some
7491 	 * remaining we need to start it at zero.
7492 	 */
7493 	rsm->r_dupack = 0;
7494 	/* Now do we consume the whole thing? */
7495 	if (SEQ_GEQ(th_ack, rsm->r_end)) {
7496 		/* Its all consumed. */
7497 		uint32_t left;
7498 
7499 		if (rsm->r_flags & BBR_ACKED) {
7500 			/*
7501 			 * It was acked on the scoreboard -- remove it from
7502 			 * total
7503 			 */
7504 			p_acked += (rsm->r_end - rsm->r_start);
7505 			bbr->r_ctl.rc_sacked -= (rsm->r_end - rsm->r_start);
7506 			if (bbr->r_ctl.rc_sacked == 0)
7507 				bbr->r_ctl.rc_sacklast = NULL;
7508 		} else {
7509 			bbr_update_rtt(tp, bbr, rsm, to, cts, BBR_CUM_ACKED, th_ack);
7510 			if (rsm->r_flags & BBR_MARKED_LOST) {
7511 				bbr->r_ctl.rc_lost_bytes -= rsm->r_end - rsm->r_start;
7512 			}
7513 			if (rsm->r_flags & BBR_SACK_PASSED) {
7514 				/*
7515 				 * There are acked segments ACKED on the
7516 				 * scoreboard further up. We are seeing
7517 				 * reordering.
7518 				 */
7519 				BBR_STAT_INC(bbr_reorder_seen);
7520 				bbr->r_ctl.rc_reorder_ts = cts;
7521 				if (rsm->r_flags & BBR_MARKED_LOST) {
7522 					bbr->r_ctl.rc_lost -= rsm->r_end - rsm->r_start;
7523 					if (SEQ_GT(bbr->r_ctl.rc_lt_lost, bbr->r_ctl.rc_lost))
7524 						/* LT sampling also needs adjustment */
7525 						bbr->r_ctl.rc_lt_lost = bbr->r_ctl.rc_lost;
7526 				}
7527 			}
7528 			rsm->r_flags &= ~BBR_MARKED_LOST;
7529 		}
7530 		bbr->r_ctl.rc_holes_rxt -= rsm->r_rtr_bytes;
7531 		rsm->r_rtr_bytes = 0;
7532 		TAILQ_REMOVE(&bbr->r_ctl.rc_map, rsm, r_next);
7533 		if (rsm->r_in_tmap) {
7534 			TAILQ_REMOVE(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
7535 			rsm->r_in_tmap = 0;
7536 		}
7537 		if (bbr->r_ctl.rc_next == rsm) {
7538 			/* scoot along the marker */
7539 			bbr->r_ctl.rc_next = TAILQ_FIRST(&bbr->r_ctl.rc_map);
7540 		}
7541 		bbr_isit_a_pkt_epoch(bbr, cts, rsm, __LINE__, BBR_CUM_ACKED);
7542 		/* Adjust the packet counts */
7543 		left = th_ack - rsm->r_end;
7544 		/* Free back to zone */
7545 		bbr_free(bbr, rsm);
7546 		if (left) {
7547 			rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
7548 			goto more;
7549 		}
7550 		goto proc_sack;
7551 	}
7552 	if (rsm->r_flags & BBR_ACKED) {
7553 		/*
7554 		 * It was acked on the scoreboard -- remove it from total
7555 		 * for the part being cum-acked.
7556 		 */
7557 		p_acked += (rsm->r_end - rsm->r_start);
7558 		bbr->r_ctl.rc_sacked -= (th_ack - rsm->r_start);
7559 		if (bbr->r_ctl.rc_sacked == 0)
7560 			bbr->r_ctl.rc_sacklast = NULL;
7561 	} else {
7562 		/*
7563 		 * It was acked up to th_ack point for the first time
7564 		 */
7565 		struct bbr_sendmap lrsm;
7566 
7567 		memcpy(&lrsm, rsm, sizeof(struct bbr_sendmap));
7568 		lrsm.r_end = th_ack;
7569 		bbr_update_rtt(tp, bbr, &lrsm, to, cts, BBR_CUM_ACKED, th_ack);
7570 	}
7571 	if ((rsm->r_flags & BBR_MARKED_LOST) &&
7572 	    ((rsm->r_flags & BBR_ACKED) == 0)) {
7573 		/*
7574 		 * It was marked lost and partly ack'd now
7575 		 * for the first time. We lower the rc_lost_bytes
7576 		 * and still leave it MARKED.
7577 		 */
7578 		bbr->r_ctl.rc_lost_bytes -= th_ack - rsm->r_start;
7579 	}
7580 	bbr_isit_a_pkt_epoch(bbr, cts, rsm, __LINE__, BBR_CUM_ACKED);
7581 	bbr->r_ctl.rc_holes_rxt -= rsm->r_rtr_bytes;
7582 	rsm->r_rtr_bytes = 0;
7583 	/* adjust packet count */
7584 	rsm->r_start = th_ack;
7585 proc_sack:
7586 	/* Check for reneging */
7587 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
7588 	if (rsm && (rsm->r_flags & BBR_ACKED) && (th_ack == rsm->r_start)) {
7589 		/*
7590 		 * The peer has moved snd_una up to the edge of this send,
7591 		 * i.e. one that it had previously acked. The only way that
7592 		 * can be true if the peer threw away data (space issues)
7593 		 * that it had previously sacked (else it would have given
7594 		 * us snd_una up to (rsm->r_end). We need to undo the acked
7595 		 * markings here.
7596 		 *
7597 		 * Note we have to look to make sure th_ack is our
7598 		 * rsm->r_start in case we get an old ack where th_ack is
7599 		 * behind snd_una.
7600 		 */
7601 		bbr_peer_reneges(bbr, rsm, th->th_ack);
7602 	}
7603 	if ((to->to_flags & TOF_SACK) == 0) {
7604 		/* We are done nothing left to log */
7605 		goto out;
7606 	}
7607 	rsm = TAILQ_LAST_FAST(&bbr->r_ctl.rc_map, bbr_sendmap, r_next);
7608 	if (rsm) {
7609 		last_seq = rsm->r_end;
7610 	} else {
7611 		last_seq = tp->snd_max;
7612 	}
7613 	/* Sack block processing */
7614 	if (SEQ_GT(th_ack, tp->snd_una))
7615 		ack_point = th_ack;
7616 	else
7617 		ack_point = tp->snd_una;
7618 	for (i = 0; i < to->to_nsacks; i++) {
7619 		bcopy((to->to_sacks + i * TCPOLEN_SACK),
7620 		    &sack, sizeof(sack));
7621 		sack.start = ntohl(sack.start);
7622 		sack.end = ntohl(sack.end);
7623 		if (SEQ_GT(sack.end, sack.start) &&
7624 		    SEQ_GT(sack.start, ack_point) &&
7625 		    SEQ_LT(sack.start, tp->snd_max) &&
7626 		    SEQ_GT(sack.end, ack_point) &&
7627 		    SEQ_LEQ(sack.end, tp->snd_max)) {
7628 			if ((bbr->r_ctl.rc_num_small_maps_alloced > bbr_sack_block_limit) &&
7629 			    (SEQ_LT(sack.end, last_seq)) &&
7630 			    ((sack.end - sack.start) < (p_maxseg / 8))) {
7631 				/*
7632 				 * Not the last piece and its smaller than
7633 				 * 1/8th of a p_maxseg. We ignore this.
7634 				 */
7635 				BBR_STAT_INC(bbr_runt_sacks);
7636 				continue;
7637 			}
7638 			sack_blocks[num_sack_blks] = sack;
7639 			num_sack_blks++;
7640 #ifdef NETFLIX_STATS
7641 		} else if (SEQ_LEQ(sack.start, th_ack) &&
7642 		    SEQ_LEQ(sack.end, th_ack)) {
7643 			/*
7644 			 * Its a D-SACK block.
7645 			 */
7646 			tcp_record_dsack(sack.start, sack.end);
7647 #endif
7648 		}
7649 	}
7650 	if (num_sack_blks == 0)
7651 		goto out;
7652 	/*
7653 	 * Sort the SACK blocks so we can update the rack scoreboard with
7654 	 * just one pass.
7655 	 */
7656 	new_sb = sack_filter_blks(&bbr->r_ctl.bbr_sf, sack_blocks,
7657 				  num_sack_blks, th->th_ack);
7658 	ctf_log_sack_filter(bbr->rc_tp, new_sb, sack_blocks);
7659 	BBR_STAT_ADD(bbr_sack_blocks, num_sack_blks);
7660 	BBR_STAT_ADD(bbr_sack_blocks_skip, (num_sack_blks - new_sb));
7661 	num_sack_blks = new_sb;
7662 	if (num_sack_blks < 2) {
7663 		goto do_sack_work;
7664 	}
7665 	/* Sort the sacks */
7666 	for (i = 0; i < num_sack_blks; i++) {
7667 		for (j = i + 1; j < num_sack_blks; j++) {
7668 			if (SEQ_GT(sack_blocks[i].end, sack_blocks[j].end)) {
7669 				sack = sack_blocks[i];
7670 				sack_blocks[i] = sack_blocks[j];
7671 				sack_blocks[j] = sack;
7672 			}
7673 		}
7674 	}
7675 	/*
7676 	 * Now are any of the sack block ends the same (yes some
7677 	 * implememtations send these)?
7678 	 */
7679 again:
7680 	if (num_sack_blks > 1) {
7681 		for (i = 0; i < num_sack_blks; i++) {
7682 			for (j = i + 1; j < num_sack_blks; j++) {
7683 				if (sack_blocks[i].end == sack_blocks[j].end) {
7684 					/*
7685 					 * Ok these two have the same end we
7686 					 * want the smallest end and then
7687 					 * throw away the larger and start
7688 					 * again.
7689 					 */
7690 					if (SEQ_LT(sack_blocks[j].start, sack_blocks[i].start)) {
7691 						/*
7692 						 * The second block covers
7693 						 * more area use that
7694 						 */
7695 						sack_blocks[i].start = sack_blocks[j].start;
7696 					}
7697 					/*
7698 					 * Now collapse out the dup-sack and
7699 					 * lower the count
7700 					 */
7701 					for (k = (j + 1); k < num_sack_blks; k++) {
7702 						sack_blocks[j].start = sack_blocks[k].start;
7703 						sack_blocks[j].end = sack_blocks[k].end;
7704 						j++;
7705 					}
7706 					num_sack_blks--;
7707 					goto again;
7708 				}
7709 			}
7710 		}
7711 	}
7712 do_sack_work:
7713 	rsm = bbr->r_ctl.rc_sacklast;
7714 	for (i = 0; i < num_sack_blks; i++) {
7715 		acked = bbr_proc_sack_blk(tp, bbr, &sack_blocks[i], to, &rsm, cts);
7716 		if (acked) {
7717 			bbr->r_wanted_output = 1;
7718 			changed += acked;
7719 			sack_changed += acked;
7720 		}
7721 	}
7722 out:
7723 	*prev_acked = p_acked;
7724 	if ((sack_changed) && (!IN_RECOVERY(tp->t_flags))) {
7725 		/*
7726 		 * Ok we have a high probability that we need to go in to
7727 		 * recovery since we have data sack'd
7728 		 */
7729 		struct bbr_sendmap *rsm;
7730 
7731 		rsm = bbr_check_recovery_mode(tp, bbr, cts);
7732 		if (rsm) {
7733 			/* Enter recovery */
7734 			entered_recovery = 1;
7735 			bbr->r_wanted_output = 1;
7736 			/*
7737 			 * When we enter recovery we need to assure we send
7738 			 * one packet.
7739 			 */
7740 			if (bbr->r_ctl.rc_resend == NULL) {
7741 				bbr->r_ctl.rc_resend = rsm;
7742 			}
7743 		}
7744 	}
7745 	if (IN_RECOVERY(tp->t_flags) && (entered_recovery == 0)) {
7746 		/*
7747 		 * See if we need to rack-retransmit anything if so set it
7748 		 * up as the thing to resend assuming something else is not
7749 		 * already in that position.
7750 		 */
7751 		if (bbr->r_ctl.rc_resend == NULL) {
7752 			bbr->r_ctl.rc_resend = bbr_check_recovery_mode(tp, bbr, cts);
7753 		}
7754 	}
7755 	/*
7756 	 * We return the amount that changed via sack, this is used by the
7757 	 * ack-received code to augment what was changed between th_ack <->
7758 	 * snd_una.
7759 	 */
7760 	return (sack_changed);
7761 }
7762 
7763 static void
7764 bbr_strike_dupack(struct tcp_bbr *bbr)
7765 {
7766 	struct bbr_sendmap *rsm;
7767 
7768 	rsm = TAILQ_FIRST(&bbr->r_ctl.rc_tmap);
7769 	if (rsm && (rsm->r_dupack < 0xff)) {
7770 		rsm->r_dupack++;
7771 		if (rsm->r_dupack >= DUP_ACK_THRESHOLD)
7772 			bbr->r_wanted_output = 1;
7773 	}
7774 }
7775 
7776 /*
7777  * Return value of 1, we do not need to call bbr_process_data().
7778  * return value of 0, bbr_process_data can be called.
7779  * For ret_val if its 0 the TCB is locked and valid, if its non-zero
7780  * its unlocked and probably unsafe to touch the TCB.
7781  */
7782 static int
7783 bbr_process_ack(struct mbuf *m, struct tcphdr *th, struct socket *so,
7784     struct tcpcb *tp, struct tcpopt *to,
7785     uint32_t tiwin, int32_t tlen,
7786     int32_t * ofia, int32_t thflags, int32_t * ret_val)
7787 {
7788 	int32_t ourfinisacked = 0;
7789 	int32_t acked_amount;
7790 	uint16_t nsegs;
7791 	int32_t acked;
7792 	uint32_t lost, sack_changed = 0;
7793 	struct mbuf *mfree;
7794 	struct tcp_bbr *bbr;
7795 	uint32_t prev_acked = 0;
7796 
7797 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
7798 	lost = bbr->r_ctl.rc_lost;
7799 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
7800 	if (SEQ_GT(th->th_ack, tp->snd_max)) {
7801 		ctf_do_dropafterack(m, tp, th, thflags, tlen, ret_val);
7802 		bbr->r_wanted_output = 1;
7803 		return (1);
7804 	}
7805 	if (SEQ_GEQ(th->th_ack, tp->snd_una) || to->to_nsacks) {
7806 		/* Process the ack */
7807 		if (bbr->rc_in_persist)
7808 			tp->t_rxtshift = 0;
7809 		if ((th->th_ack == tp->snd_una) && (tiwin == tp->snd_wnd))
7810 		        bbr_strike_dupack(bbr);
7811 		sack_changed = bbr_log_ack(tp, to, th, &prev_acked);
7812 	}
7813 	bbr_lt_bw_sampling(bbr, bbr->r_ctl.rc_rcvtime, (bbr->r_ctl.rc_lost > lost));
7814 	if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
7815 		/*
7816 		 * Old ack, behind the last one rcv'd or a duplicate ack
7817 		 * with SACK info.
7818 		 */
7819 		if (th->th_ack == tp->snd_una) {
7820 			bbr_ack_received(tp, bbr, th, 0, sack_changed, prev_acked, __LINE__, 0);
7821 			if (bbr->r_state == TCPS_SYN_SENT) {
7822 				/*
7823 				 * Special case on where we sent SYN. When
7824 				 * the SYN-ACK is processed in syn_sent
7825 				 * state it bumps the snd_una. This causes
7826 				 * us to hit here even though we did ack 1
7827 				 * byte.
7828 				 *
7829 				 * Go through the nothing left case so we
7830 				 * send data.
7831 				 */
7832 				goto nothing_left;
7833 			}
7834 		}
7835 		return (0);
7836 	}
7837 	/*
7838 	 * If we reach this point, ACK is not a duplicate, i.e., it ACKs
7839 	 * something we sent.
7840 	 */
7841 	if (tp->t_flags & TF_NEEDSYN) {
7842 		/*
7843 		 * T/TCP: Connection was half-synchronized, and our SYN has
7844 		 * been ACK'd (so connection is now fully synchronized).  Go
7845 		 * to non-starred state, increment snd_una for ACK of SYN,
7846 		 * and check if we can do window scaling.
7847 		 */
7848 		tp->t_flags &= ~TF_NEEDSYN;
7849 		tp->snd_una++;
7850 		/* Do window scaling? */
7851 		if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
7852 		    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
7853 			tp->rcv_scale = tp->request_r_scale;
7854 			/* Send window already scaled. */
7855 		}
7856 	}
7857 	INP_WLOCK_ASSERT(tp->t_inpcb);
7858 
7859 	acked = BYTES_THIS_ACK(tp, th);
7860 	KMOD_TCPSTAT_ADD(tcps_rcvackpack, (int)nsegs);
7861 	KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
7862 
7863 	/*
7864 	 * If we just performed our first retransmit, and the ACK arrives
7865 	 * within our recovery window, then it was a mistake to do the
7866 	 * retransmit in the first place.  Recover our original cwnd and
7867 	 * ssthresh, and proceed to transmit where we left off.
7868 	 */
7869 	if (tp->t_flags & TF_PREVVALID) {
7870 		tp->t_flags &= ~TF_PREVVALID;
7871 		if (tp->t_rxtshift == 1 &&
7872 		    (int)(ticks - tp->t_badrxtwin) < 0)
7873 			bbr_cong_signal(tp, th, CC_RTO_ERR, NULL);
7874 	}
7875 	SOCKBUF_LOCK(&so->so_snd);
7876 	acked_amount = min(acked, (int)sbavail(&so->so_snd));
7877 	tp->snd_wnd -= acked_amount;
7878 	mfree = sbcut_locked(&so->so_snd, acked_amount);
7879 	SOCKBUF_UNLOCK(&so->so_snd);
7880 	tp->t_flags |= TF_WAKESOW;
7881 	m_freem(mfree);
7882 	if (SEQ_GT(th->th_ack, tp->snd_una)) {
7883 		bbr_collapse_rtt(tp, bbr, TCP_REXMTVAL(tp));
7884 	}
7885 	tp->snd_una = th->th_ack;
7886 	bbr_ack_received(tp, bbr, th, acked, sack_changed, prev_acked, __LINE__, (bbr->r_ctl.rc_lost - lost));
7887 	if (IN_RECOVERY(tp->t_flags)) {
7888 		if (SEQ_LT(th->th_ack, tp->snd_recover) &&
7889 		    (SEQ_LT(th->th_ack, tp->snd_max))) {
7890 			tcp_bbr_partialack(tp);
7891 		} else {
7892 			bbr_post_recovery(tp);
7893 		}
7894 	}
7895 	if (SEQ_GT(tp->snd_una, tp->snd_recover)) {
7896 		tp->snd_recover = tp->snd_una;
7897 	}
7898 	if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
7899 		tp->snd_nxt = tp->snd_max;
7900 	}
7901 	if (tp->snd_una == tp->snd_max) {
7902 		/* Nothing left outstanding */
7903 nothing_left:
7904 		bbr_log_progress_event(bbr, tp, ticks, PROGRESS_CLEAR, __LINE__);
7905 		if (sbavail(&tp->t_inpcb->inp_socket->so_snd) == 0)
7906 			bbr->rc_tp->t_acktime = 0;
7907 		if ((sbused(&so->so_snd) == 0) &&
7908 		    (tp->t_flags & TF_SENTFIN)) {
7909 			ourfinisacked = 1;
7910 		}
7911 		bbr_timer_cancel(bbr, __LINE__, bbr->r_ctl.rc_rcvtime);
7912 		if (bbr->rc_in_persist == 0) {
7913 			bbr->r_ctl.rc_went_idle_time = bbr->r_ctl.rc_rcvtime;
7914 		}
7915 		sack_filter_clear(&bbr->r_ctl.bbr_sf, tp->snd_una);
7916 		bbr_log_ack_clear(bbr, bbr->r_ctl.rc_rcvtime);
7917 		/*
7918 		 * We invalidate the last ack here since we
7919 		 * don't want to transfer forward the time
7920 		 * for our sum's calculations.
7921 		 */
7922 		if ((tp->t_state >= TCPS_FIN_WAIT_1) &&
7923 		    (sbavail(&so->so_snd) == 0) &&
7924 		    (tp->t_flags2 & TF2_DROP_AF_DATA)) {
7925 			/*
7926 			 * The socket was gone and the peer sent data, time
7927 			 * to reset him.
7928 			 */
7929 			*ret_val = 1;
7930 			tcp_log_end_status(tp, TCP_EI_STATUS_DATA_A_CLOSE);
7931 			/* tcp_close will kill the inp pre-log the Reset */
7932 			tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
7933 			tp = tcp_close(tp);
7934 			ctf_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, tlen);
7935 			BBR_STAT_INC(bbr_dropped_af_data);
7936 			return (1);
7937 		}
7938 		/* Set need output so persist might get set */
7939 		bbr->r_wanted_output = 1;
7940 	}
7941 	if (ofia)
7942 		*ofia = ourfinisacked;
7943 	return (0);
7944 }
7945 
7946 static void
7947 bbr_enter_persist(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts, int32_t line)
7948 {
7949 	if (bbr->rc_in_persist == 0) {
7950 		bbr_timer_cancel(bbr, __LINE__, cts);
7951 		bbr->r_ctl.rc_last_delay_val = 0;
7952 		tp->t_rxtshift = 0;
7953 		bbr->rc_in_persist = 1;
7954 		bbr->r_ctl.rc_went_idle_time = cts;
7955 		/* We should be capped when rw went to 0 but just in case */
7956 		bbr_log_type_pesist(bbr, cts, 0, line, 1);
7957 		/* Time freezes for the state, so do the accounting now */
7958 		if (SEQ_GT(cts, bbr->r_ctl.rc_bbr_state_time)) {
7959 			uint32_t time_in;
7960 
7961 			time_in = cts - bbr->r_ctl.rc_bbr_state_time;
7962 			if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW) {
7963 				int32_t idx;
7964 
7965 				idx = bbr_state_val(bbr);
7966 				counter_u64_add(bbr_state_time[(idx + 5)], time_in);
7967 			} else {
7968 				counter_u64_add(bbr_state_time[bbr->rc_bbr_state], time_in);
7969 			}
7970 		}
7971 		bbr->r_ctl.rc_bbr_state_time = cts;
7972 	}
7973 }
7974 
7975 static void
7976 bbr_restart_after_idle(struct tcp_bbr *bbr, uint32_t cts, uint32_t idle_time)
7977 {
7978 	/*
7979 	 * Note that if idle time does not exceed our
7980 	 * threshold, we do nothing continuing the state
7981 	 * transitions we were last walking through.
7982 	 */
7983 	if (idle_time >= bbr_idle_restart_threshold) {
7984 		if (bbr->rc_use_idle_restart) {
7985 			bbr->rc_bbr_state = BBR_STATE_IDLE_EXIT;
7986 			/*
7987 			 * Set our target using BBR_UNIT, so
7988 			 * we increase at a dramatic rate but
7989 			 * we stop when we get the pipe
7990 			 * full again for our current b/w estimate.
7991 			 */
7992 			bbr->r_ctl.rc_bbr_hptsi_gain = BBR_UNIT;
7993 			bbr->r_ctl.rc_bbr_cwnd_gain = BBR_UNIT;
7994 			bbr_set_state_target(bbr, __LINE__);
7995 			/* Now setup our gains to ramp up */
7996 			bbr->r_ctl.rc_bbr_hptsi_gain = bbr->r_ctl.rc_startup_pg;
7997 			bbr->r_ctl.rc_bbr_cwnd_gain = bbr->r_ctl.rc_startup_pg;
7998 			bbr_log_type_statechange(bbr, cts, __LINE__);
7999 		} else if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW) {
8000 			bbr_substate_change(bbr, cts, __LINE__, 1);
8001 		}
8002 	}
8003 }
8004 
8005 static void
8006 bbr_exit_persist(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts, int32_t line)
8007 {
8008 	uint32_t idle_time;
8009 
8010 	if (bbr->rc_in_persist == 0)
8011 		return;
8012 	idle_time = bbr_calc_time(cts, bbr->r_ctl.rc_went_idle_time);
8013 	bbr->rc_in_persist = 0;
8014 	bbr->rc_hit_state_1 = 0;
8015 	bbr->r_ctl.rc_del_time = cts;
8016 	/*
8017 	 * We invalidate the last ack here since we
8018 	 * don't want to transfer forward the time
8019 	 * for our sum's calculations.
8020 	 */
8021 	if (bbr->rc_inp->inp_in_hpts) {
8022 		tcp_hpts_remove(bbr->rc_inp, HPTS_REMOVE_OUTPUT);
8023 		bbr->rc_timer_first = 0;
8024 		bbr->r_ctl.rc_hpts_flags = 0;
8025 		bbr->r_ctl.rc_last_delay_val = 0;
8026 		bbr->r_ctl.rc_hptsi_agg_delay = 0;
8027 		bbr->r_agg_early_set = 0;
8028 		bbr->r_ctl.rc_agg_early = 0;
8029 	}
8030 	bbr_log_type_pesist(bbr, cts, idle_time, line, 0);
8031 	if (idle_time >= bbr_rtt_probe_time) {
8032 		/*
8033 		 * This qualifies as a RTT_PROBE session since we drop the
8034 		 * data outstanding to nothing and waited more than
8035 		 * bbr_rtt_probe_time.
8036 		 */
8037 		bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_PERSIST, 0);
8038 		bbr->r_ctl.last_in_probertt = bbr->r_ctl.rc_rtt_shrinks = cts;
8039 	}
8040 	tp->t_rxtshift = 0;
8041 	/*
8042 	 * If in probeBW and we have persisted more than an RTT lets do
8043 	 * special handling.
8044 	 */
8045 	/* Force a time based epoch */
8046 	bbr_set_epoch(bbr, cts, __LINE__);
8047 	/*
8048 	 * Setup the lost so we don't count anything against the guy
8049 	 * we have been stuck with during persists.
8050 	 */
8051 	bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
8052 	/* Time un-freezes for the state */
8053 	bbr->r_ctl.rc_bbr_state_time = cts;
8054 	if ((bbr->rc_bbr_state == BBR_STATE_PROBE_BW) ||
8055 	    (bbr->rc_bbr_state == BBR_STATE_PROBE_RTT)) {
8056 		/*
8057 		 * If we are going back to probe-bw
8058 		 * or probe_rtt, we may need to possibly
8059 		 * do a fast restart.
8060 		 */
8061 		bbr_restart_after_idle(bbr, cts, idle_time);
8062 	}
8063 }
8064 
8065 static void
8066 bbr_collapsed_window(struct tcp_bbr *bbr)
8067 {
8068 	/*
8069 	 * Now we must walk the
8070 	 * send map and divide the
8071 	 * ones left stranded. These
8072 	 * guys can't cause us to abort
8073 	 * the connection and are really
8074 	 * "unsent". However if a buggy
8075 	 * client actually did keep some
8076 	 * of the data i.e. collapsed the win
8077 	 * and refused to ack and then opened
8078 	 * the win and acked that data. We would
8079 	 * get into an ack war, the simplier
8080 	 * method then of just pretending we
8081 	 * did not send those segments something
8082 	 * won't work.
8083 	 */
8084 	struct bbr_sendmap *rsm, *nrsm;
8085 	tcp_seq max_seq;
8086 	uint32_t maxseg;
8087 	int can_split = 0;
8088 	int fnd = 0;
8089 
8090 	maxseg = bbr->rc_tp->t_maxseg - bbr->rc_last_options;
8091 	max_seq = bbr->rc_tp->snd_una + bbr->rc_tp->snd_wnd;
8092 	bbr_log_type_rwnd_collapse(bbr, max_seq, 1, 0);
8093 	TAILQ_FOREACH(rsm, &bbr->r_ctl.rc_map, r_next) {
8094 		/* Find the first seq past or at maxseq */
8095 		if (rsm->r_flags & BBR_RWND_COLLAPSED)
8096 			rsm->r_flags &= ~BBR_RWND_COLLAPSED;
8097 		if (SEQ_GEQ(max_seq, rsm->r_start) &&
8098 		    SEQ_GEQ(rsm->r_end, max_seq)) {
8099 			fnd = 1;
8100 			break;
8101 		}
8102 	}
8103 	bbr->rc_has_collapsed = 0;
8104 	if (!fnd) {
8105 		/* Nothing to do strange */
8106 		return;
8107 	}
8108 	/*
8109 	 * Now can we split?
8110 	 *
8111 	 * We don't want to split if splitting
8112 	 * would generate too many small segments
8113 	 * less we let an attacker fragment our
8114 	 * send_map and leave us out of memory.
8115 	 */
8116 	if ((max_seq != rsm->r_start) &&
8117 	    (max_seq != rsm->r_end)){
8118 		/* can we split? */
8119 		int res1, res2;
8120 
8121 		res1 = max_seq - rsm->r_start;
8122 		res2 = rsm->r_end - max_seq;
8123 		if ((res1 >= (maxseg/8)) &&
8124 		    (res2 >= (maxseg/8))) {
8125 			/* No small pieces here */
8126 			can_split = 1;
8127 		} else if (bbr->r_ctl.rc_num_small_maps_alloced < bbr_sack_block_limit) {
8128 			/* We are under the limit */
8129 			can_split = 1;
8130 		}
8131 	}
8132 	/* Ok do we need to split this rsm? */
8133 	if (max_seq == rsm->r_start) {
8134 		/* It's this guy no split required */
8135 		nrsm = rsm;
8136 	} else if (max_seq == rsm->r_end) {
8137 		/* It's the next one no split required. */
8138 		nrsm = TAILQ_NEXT(rsm, r_next);
8139 		if (nrsm == NULL) {
8140 			/* Huh? */
8141 			return;
8142 		}
8143 	} else if (can_split && SEQ_LT(max_seq, rsm->r_end)) {
8144 		/* yep we need to split it */
8145 		nrsm = bbr_alloc_limit(bbr, BBR_LIMIT_TYPE_SPLIT);
8146 		if (nrsm == NULL) {
8147 			/* failed XXXrrs what can we do mark the whole? */
8148 			nrsm = rsm;
8149 			goto no_split;
8150 		}
8151 		/* Clone it */
8152 		bbr_log_type_rwnd_collapse(bbr, max_seq, 3, 0);
8153 		bbr_clone_rsm(bbr, nrsm, rsm, max_seq);
8154 		TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_map, rsm, nrsm, r_next);
8155 		if (rsm->r_in_tmap) {
8156 			TAILQ_INSERT_AFTER(&bbr->r_ctl.rc_tmap, rsm, nrsm, r_tnext);
8157 			nrsm->r_in_tmap = 1;
8158 		}
8159 	} else {
8160 		/*
8161 		 * Split not allowed just start here just
8162 		 * use this guy.
8163 		 */
8164 		nrsm = rsm;
8165 	}
8166 no_split:
8167 	BBR_STAT_INC(bbr_collapsed_win);
8168 	/* reuse fnd as a count */
8169 	fnd = 0;
8170 	TAILQ_FOREACH_FROM(nrsm, &bbr->r_ctl.rc_map, r_next) {
8171 		nrsm->r_flags |= BBR_RWND_COLLAPSED;
8172 		fnd++;
8173 		bbr->rc_has_collapsed = 1;
8174 	}
8175 	bbr_log_type_rwnd_collapse(bbr, max_seq, 4, fnd);
8176 }
8177 
8178 static void
8179 bbr_un_collapse_window(struct tcp_bbr *bbr)
8180 {
8181 	struct bbr_sendmap *rsm;
8182 	int cleared = 0;
8183 
8184 	TAILQ_FOREACH_REVERSE(rsm, &bbr->r_ctl.rc_map, bbr_head, r_next) {
8185 		if (rsm->r_flags & BBR_RWND_COLLAPSED) {
8186 			/* Clear the flag */
8187 			rsm->r_flags &= ~BBR_RWND_COLLAPSED;
8188 			cleared++;
8189 		} else
8190 			break;
8191 	}
8192 	bbr_log_type_rwnd_collapse(bbr,
8193 				   (bbr->rc_tp->snd_una + bbr->rc_tp->snd_wnd), 0, cleared);
8194 	bbr->rc_has_collapsed = 0;
8195 }
8196 
8197 /*
8198  * Return value of 1, the TCB is unlocked and most
8199  * likely gone, return value of 0, the TCB is still
8200  * locked.
8201  */
8202 static int
8203 bbr_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so,
8204     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen,
8205     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt)
8206 {
8207 	/*
8208 	 * Update window information. Don't look at window if no ACK: TAC's
8209 	 * send garbage on first SYN.
8210 	 */
8211 	uint16_t nsegs;
8212 	int32_t tfo_syn;
8213 	struct tcp_bbr *bbr;
8214 
8215 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
8216 	INP_WLOCK_ASSERT(tp->t_inpcb);
8217 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
8218 	if ((thflags & TH_ACK) &&
8219 	    (SEQ_LT(tp->snd_wl1, th->th_seq) ||
8220 	    (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) ||
8221 	    (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) {
8222 		/* keep track of pure window updates */
8223 		if (tlen == 0 &&
8224 		    tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd)
8225 			KMOD_TCPSTAT_INC(tcps_rcvwinupd);
8226 		tp->snd_wnd = tiwin;
8227 		tp->snd_wl1 = th->th_seq;
8228 		tp->snd_wl2 = th->th_ack;
8229 		if (tp->snd_wnd > tp->max_sndwnd)
8230 			tp->max_sndwnd = tp->snd_wnd;
8231 		bbr->r_wanted_output = 1;
8232 	} else if (thflags & TH_ACK) {
8233 		if ((tp->snd_wl2 == th->th_ack) && (tiwin < tp->snd_wnd)) {
8234 			tp->snd_wnd = tiwin;
8235 			tp->snd_wl1 = th->th_seq;
8236 			tp->snd_wl2 = th->th_ack;
8237 		}
8238 	}
8239 	if (tp->snd_wnd < ctf_outstanding(tp))
8240 		/* The peer collapsed its window on us */
8241 		bbr_collapsed_window(bbr);
8242  	else if (bbr->rc_has_collapsed)
8243 		bbr_un_collapse_window(bbr);
8244 	/* Was persist timer active and now we have window space? */
8245 	if ((bbr->rc_in_persist != 0) &&
8246 	    (tp->snd_wnd >= min((bbr->r_ctl.rc_high_rwnd/2),
8247 				bbr_minseg(bbr)))) {
8248 		/*
8249 		 * Make the rate persist at end of persist mode if idle long
8250 		 * enough
8251 		 */
8252 		bbr_exit_persist(tp, bbr, bbr->r_ctl.rc_rcvtime, __LINE__);
8253 
8254 		/* Make sure we output to start the timer */
8255 		bbr->r_wanted_output = 1;
8256 	}
8257 	/* Do we need to enter persist? */
8258 	if ((bbr->rc_in_persist == 0) &&
8259 	    (tp->snd_wnd < min((bbr->r_ctl.rc_high_rwnd/2), bbr_minseg(bbr))) &&
8260 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
8261 	    (tp->snd_max == tp->snd_una) &&
8262 	    sbavail(&tp->t_inpcb->inp_socket->so_snd) &&
8263 	    (sbavail(&tp->t_inpcb->inp_socket->so_snd) > tp->snd_wnd)) {
8264 		/* No send window.. we must enter persist */
8265 		bbr_enter_persist(tp, bbr, bbr->r_ctl.rc_rcvtime, __LINE__);
8266 	}
8267 	if (tp->t_flags2 & TF2_DROP_AF_DATA) {
8268 		m_freem(m);
8269 		return (0);
8270 	}
8271 	/*
8272 	 * We don't support urgent data but
8273 	 * drag along the up just to make sure
8274 	 * if there is a stack switch no one
8275 	 * is surprised.
8276 	 */
8277 	tp->rcv_up = tp->rcv_nxt;
8278 	INP_WLOCK_ASSERT(tp->t_inpcb);
8279 
8280 	/*
8281 	 * Process the segment text, merging it into the TCP sequencing
8282 	 * queue, and arranging for acknowledgment of receipt if necessary.
8283 	 * This process logically involves adjusting tp->rcv_wnd as data is
8284 	 * presented to the user (this happens in tcp_usrreq.c, case
8285 	 * PRU_RCVD).  If a FIN has already been received on this connection
8286 	 * then we just ignore the text.
8287 	 */
8288 	tfo_syn = ((tp->t_state == TCPS_SYN_RECEIVED) &&
8289 		   IS_FASTOPEN(tp->t_flags));
8290 	if ((tlen || (thflags & TH_FIN) || (tfo_syn && tlen > 0)) &&
8291 	    TCPS_HAVERCVDFIN(tp->t_state) == 0) {
8292 		tcp_seq save_start = th->th_seq;
8293 		tcp_seq save_rnxt  = tp->rcv_nxt;
8294 		int     save_tlen  = tlen;
8295 
8296 		m_adj(m, drop_hdrlen);	/* delayed header drop */
8297 		/*
8298 		 * Insert segment which includes th into TCP reassembly
8299 		 * queue with control block tp.  Set thflags to whether
8300 		 * reassembly now includes a segment with FIN.  This handles
8301 		 * the common case inline (segment is the next to be
8302 		 * received on an established connection, and the queue is
8303 		 * empty), avoiding linkage into and removal from the queue
8304 		 * and repetition of various conversions. Set DELACK for
8305 		 * segments received in order, but ack immediately when
8306 		 * segments are out of order (so fast retransmit can work).
8307 		 */
8308 		if (th->th_seq == tp->rcv_nxt &&
8309 		    SEGQ_EMPTY(tp) &&
8310 		    (TCPS_HAVEESTABLISHED(tp->t_state) ||
8311 		    tfo_syn)) {
8312 #ifdef NETFLIX_SB_LIMITS
8313 			u_int mcnt, appended;
8314 
8315 			if (so->so_rcv.sb_shlim) {
8316 				mcnt = m_memcnt(m);
8317 				appended = 0;
8318 				if (counter_fo_get(so->so_rcv.sb_shlim, mcnt,
8319 				    CFO_NOSLEEP, NULL) == false) {
8320 					counter_u64_add(tcp_sb_shlim_fails, 1);
8321 					m_freem(m);
8322 					return (0);
8323 				}
8324 			}
8325 
8326 #endif
8327 			if (DELAY_ACK(tp, bbr, nsegs) || tfo_syn) {
8328 				bbr->bbr_segs_rcvd += max(1, nsegs);
8329 				tp->t_flags |= TF_DELACK;
8330 				bbr_timer_cancel(bbr, __LINE__, bbr->r_ctl.rc_rcvtime);
8331 			} else {
8332 				bbr->r_wanted_output = 1;
8333 				tp->t_flags |= TF_ACKNOW;
8334 			}
8335 			tp->rcv_nxt += tlen;
8336 			if (tlen &&
8337 			    ((tp->t_flags2 & TF2_FBYTES_COMPLETE) == 0) &&
8338 			    (tp->t_fbyte_in == 0)) {
8339 				tp->t_fbyte_in = ticks;
8340 				if (tp->t_fbyte_in == 0)
8341 					tp->t_fbyte_in = 1;
8342 				if (tp->t_fbyte_out && tp->t_fbyte_in)
8343 					tp->t_flags2 |= TF2_FBYTES_COMPLETE;
8344 			}
8345 			thflags = th->th_flags & TH_FIN;
8346 			KMOD_TCPSTAT_ADD(tcps_rcvpack, (int)nsegs);
8347 			KMOD_TCPSTAT_ADD(tcps_rcvbyte, tlen);
8348 			SOCKBUF_LOCK(&so->so_rcv);
8349 			if (so->so_rcv.sb_state & SBS_CANTRCVMORE)
8350 				m_freem(m);
8351 			else
8352 #ifdef NETFLIX_SB_LIMITS
8353 				appended =
8354 #endif
8355 					sbappendstream_locked(&so->so_rcv, m, 0);
8356 			SOCKBUF_UNLOCK(&so->so_rcv);
8357 			tp->t_flags |= TF_WAKESOR;
8358 #ifdef NETFLIX_SB_LIMITS
8359 			if (so->so_rcv.sb_shlim && appended != mcnt)
8360 				counter_fo_release(so->so_rcv.sb_shlim,
8361 				    mcnt - appended);
8362 #endif
8363 		} else {
8364 			/*
8365 			 * XXX: Due to the header drop above "th" is
8366 			 * theoretically invalid by now.  Fortunately
8367 			 * m_adj() doesn't actually frees any mbufs when
8368 			 * trimming from the head.
8369 			 */
8370 			tcp_seq temp = save_start;
8371 			thflags = tcp_reass(tp, th, &temp, &tlen, m);
8372 			tp->t_flags |= TF_ACKNOW;
8373 		}
8374 		if ((tp->t_flags & TF_SACK_PERMIT) && (save_tlen > 0)) {
8375 			if ((tlen == 0) && (SEQ_LT(save_start, save_rnxt))) {
8376 				/*
8377 				 * DSACK actually handled in the fastpath
8378 				 * above.
8379 				 */
8380 				tcp_update_sack_list(tp, save_start,
8381 				    save_start + save_tlen);
8382 			} else if ((tlen > 0) && SEQ_GT(tp->rcv_nxt, save_rnxt)) {
8383 				if ((tp->rcv_numsacks >= 1) &&
8384 				    (tp->sackblks[0].end == save_start)) {
8385 					/*
8386 					 * Partial overlap, recorded at todrop
8387 					 * above.
8388 					 */
8389 					tcp_update_sack_list(tp,
8390 					    tp->sackblks[0].start,
8391 					    tp->sackblks[0].end);
8392 				} else {
8393 					tcp_update_dsack_list(tp, save_start,
8394 					    save_start + save_tlen);
8395 				}
8396 			} else if (tlen >= save_tlen) {
8397 				/* Update of sackblks. */
8398 				tcp_update_dsack_list(tp, save_start,
8399 				    save_start + save_tlen);
8400 			} else if (tlen > 0) {
8401 				tcp_update_dsack_list(tp, save_start,
8402 				    save_start + tlen);
8403 			}
8404 		}
8405 	} else {
8406 		m_freem(m);
8407 		thflags &= ~TH_FIN;
8408 	}
8409 
8410 	/*
8411 	 * If FIN is received ACK the FIN and let the user know that the
8412 	 * connection is closing.
8413 	 */
8414 	if (thflags & TH_FIN) {
8415 		if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
8416 			socantrcvmore(so);
8417 			/* The socket upcall is handled by socantrcvmore. */
8418 			tp->t_flags &= ~TF_WAKESOR;
8419 			/*
8420 			 * If connection is half-synchronized (ie NEEDSYN
8421 			 * flag on) then delay ACK, so it may be piggybacked
8422 			 * when SYN is sent. Otherwise, since we received a
8423 			 * FIN then no more input can be expected, send ACK
8424 			 * now.
8425 			 */
8426 			if (tp->t_flags & TF_NEEDSYN) {
8427 				tp->t_flags |= TF_DELACK;
8428 				bbr_timer_cancel(bbr,
8429 				    __LINE__, bbr->r_ctl.rc_rcvtime);
8430 			} else {
8431 				tp->t_flags |= TF_ACKNOW;
8432 			}
8433 			tp->rcv_nxt++;
8434 		}
8435 		switch (tp->t_state) {
8436 			/*
8437 			 * In SYN_RECEIVED and ESTABLISHED STATES enter the
8438 			 * CLOSE_WAIT state.
8439 			 */
8440 		case TCPS_SYN_RECEIVED:
8441 			tp->t_starttime = ticks;
8442 			/* FALLTHROUGH */
8443 		case TCPS_ESTABLISHED:
8444 			tcp_state_change(tp, TCPS_CLOSE_WAIT);
8445 			break;
8446 
8447 			/*
8448 			 * If still in FIN_WAIT_1 STATE FIN has not been
8449 			 * acked so enter the CLOSING state.
8450 			 */
8451 		case TCPS_FIN_WAIT_1:
8452 			tcp_state_change(tp, TCPS_CLOSING);
8453 			break;
8454 
8455 			/*
8456 			 * In FIN_WAIT_2 state enter the TIME_WAIT state,
8457 			 * starting the time-wait timer, turning off the
8458 			 * other standard timers.
8459 			 */
8460 		case TCPS_FIN_WAIT_2:
8461 			bbr->rc_timer_first = 1;
8462 			bbr_timer_cancel(bbr,
8463 			    __LINE__, bbr->r_ctl.rc_rcvtime);
8464 			INP_WLOCK_ASSERT(tp->t_inpcb);
8465 			tcp_twstart(tp);
8466 			return (1);
8467 		}
8468 	}
8469 	/*
8470 	 * Return any desired output.
8471 	 */
8472 	if ((tp->t_flags & TF_ACKNOW) ||
8473 	    (sbavail(&so->so_snd) > ctf_outstanding(tp))) {
8474 		bbr->r_wanted_output = 1;
8475 	}
8476 	INP_WLOCK_ASSERT(tp->t_inpcb);
8477 	return (0);
8478 }
8479 
8480 /*
8481  * Here nothing is really faster, its just that we
8482  * have broken out the fast-data path also just like
8483  * the fast-ack. Return 1 if we processed the packet
8484  * return 0 if you need to take the "slow-path".
8485  */
8486 static int
8487 bbr_do_fastnewdata(struct mbuf *m, struct tcphdr *th, struct socket *so,
8488     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
8489     uint32_t tiwin, int32_t nxt_pkt)
8490 {
8491 	uint16_t nsegs;
8492 	int32_t newsize = 0;	/* automatic sockbuf scaling */
8493 	struct tcp_bbr *bbr;
8494 #ifdef NETFLIX_SB_LIMITS
8495 	u_int mcnt, appended;
8496 #endif
8497 #ifdef TCPDEBUG
8498 	/*
8499 	 * The size of tcp_saveipgen must be the size of the max ip header,
8500 	 * now IPv6.
8501 	 */
8502 	u_char tcp_saveipgen[IP6_HDR_LEN];
8503 	struct tcphdr tcp_savetcp;
8504 	short ostate = 0;
8505 
8506 #endif
8507 	/* On the hpts and we would have called output */
8508 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
8509 
8510 	/*
8511 	 * If last ACK falls within this segment's sequence numbers, record
8512 	 * the timestamp. NOTE that the test is modified according to the
8513 	 * latest proposal of the tcplw@cray.com list (Braden 1993/04/26).
8514 	 */
8515 	if (bbr->r_ctl.rc_resend != NULL) {
8516 		return (0);
8517 	}
8518 	if (tiwin && tiwin != tp->snd_wnd) {
8519 		return (0);
8520 	}
8521 	if (__predict_false((tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN)))) {
8522 		return (0);
8523 	}
8524 	if (__predict_false((to->to_flags & TOF_TS) &&
8525 	    (TSTMP_LT(to->to_tsval, tp->ts_recent)))) {
8526 		return (0);
8527 	}
8528 	if (__predict_false((th->th_ack != tp->snd_una))) {
8529 		return (0);
8530 	}
8531 	if (__predict_false(tlen > sbspace(&so->so_rcv))) {
8532 		return (0);
8533 	}
8534 	if ((to->to_flags & TOF_TS) != 0 &&
8535 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
8536 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
8537 		tp->ts_recent = to->to_tsval;
8538 	}
8539 	/*
8540 	 * This is a pure, in-sequence data packet with nothing on the
8541 	 * reassembly queue and we have enough buffer space to take it.
8542 	 */
8543 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
8544 
8545 #ifdef NETFLIX_SB_LIMITS
8546 	if (so->so_rcv.sb_shlim) {
8547 		mcnt = m_memcnt(m);
8548 		appended = 0;
8549 		if (counter_fo_get(so->so_rcv.sb_shlim, mcnt,
8550 		    CFO_NOSLEEP, NULL) == false) {
8551 			counter_u64_add(tcp_sb_shlim_fails, 1);
8552 			m_freem(m);
8553 			return (1);
8554 		}
8555 	}
8556 #endif
8557 	/* Clean receiver SACK report if present */
8558 	if (tp->rcv_numsacks)
8559 		tcp_clean_sackreport(tp);
8560 	KMOD_TCPSTAT_INC(tcps_preddat);
8561 	tp->rcv_nxt += tlen;
8562 	if (tlen &&
8563 	    ((tp->t_flags2 & TF2_FBYTES_COMPLETE) == 0) &&
8564 	    (tp->t_fbyte_in == 0)) {
8565 		tp->t_fbyte_in = ticks;
8566 		if (tp->t_fbyte_in == 0)
8567 			tp->t_fbyte_in = 1;
8568 		if (tp->t_fbyte_out && tp->t_fbyte_in)
8569 			tp->t_flags2 |= TF2_FBYTES_COMPLETE;
8570 	}
8571 	/*
8572 	 * Pull snd_wl1 up to prevent seq wrap relative to th_seq.
8573 	 */
8574 	tp->snd_wl1 = th->th_seq;
8575 	/*
8576 	 * Pull rcv_up up to prevent seq wrap relative to rcv_nxt.
8577 	 */
8578 	tp->rcv_up = tp->rcv_nxt;
8579 	KMOD_TCPSTAT_ADD(tcps_rcvpack, (int)nsegs);
8580 	KMOD_TCPSTAT_ADD(tcps_rcvbyte, tlen);
8581 #ifdef TCPDEBUG
8582 	if (so->so_options & SO_DEBUG)
8583 		tcp_trace(TA_INPUT, ostate, tp,
8584 		    (void *)tcp_saveipgen, &tcp_savetcp, 0);
8585 #endif
8586 	newsize = tcp_autorcvbuf(m, th, so, tp, tlen);
8587 
8588 	/* Add data to socket buffer. */
8589 	SOCKBUF_LOCK(&so->so_rcv);
8590 	if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
8591 		m_freem(m);
8592 	} else {
8593 		/*
8594 		 * Set new socket buffer size. Give up when limit is
8595 		 * reached.
8596 		 */
8597 		if (newsize)
8598 			if (!sbreserve_locked(&so->so_rcv,
8599 			    newsize, so, NULL))
8600 				so->so_rcv.sb_flags &= ~SB_AUTOSIZE;
8601 		m_adj(m, drop_hdrlen);	/* delayed header drop */
8602 
8603 #ifdef NETFLIX_SB_LIMITS
8604 		appended =
8605 #endif
8606 			sbappendstream_locked(&so->so_rcv, m, 0);
8607 		ctf_calc_rwin(so, tp);
8608 	}
8609 	SOCKBUF_UNLOCK(&so->so_rcv);
8610 	tp->t_flags |= TF_WAKESOR;
8611 #ifdef NETFLIX_SB_LIMITS
8612 	if (so->so_rcv.sb_shlim && mcnt != appended)
8613 		counter_fo_release(so->so_rcv.sb_shlim, mcnt - appended);
8614 #endif
8615 	if (DELAY_ACK(tp, bbr, nsegs)) {
8616 		bbr->bbr_segs_rcvd += max(1, nsegs);
8617 		tp->t_flags |= TF_DELACK;
8618 		bbr_timer_cancel(bbr, __LINE__, bbr->r_ctl.rc_rcvtime);
8619 	} else {
8620 		bbr->r_wanted_output = 1;
8621 		tp->t_flags |= TF_ACKNOW;
8622 	}
8623 	return (1);
8624 }
8625 
8626 /*
8627  * This subfunction is used to try to highly optimize the
8628  * fast path. We again allow window updates that are
8629  * in sequence to remain in the fast-path. We also add
8630  * in the __predict's to attempt to help the compiler.
8631  * Note that if we return a 0, then we can *not* process
8632  * it and the caller should push the packet into the
8633  * slow-path. If we return 1, then all is well and
8634  * the packet is fully processed.
8635  */
8636 static int
8637 bbr_fastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
8638     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
8639     uint32_t tiwin, int32_t nxt_pkt, uint8_t iptos)
8640 {
8641 	int32_t acked;
8642 	uint16_t nsegs;
8643 	uint32_t sack_changed;
8644 #ifdef TCPDEBUG
8645 	/*
8646 	 * The size of tcp_saveipgen must be the size of the max ip header,
8647 	 * now IPv6.
8648 	 */
8649 	u_char tcp_saveipgen[IP6_HDR_LEN];
8650 	struct tcphdr tcp_savetcp;
8651 	short ostate = 0;
8652 
8653 #endif
8654 	uint32_t prev_acked = 0;
8655 	struct tcp_bbr *bbr;
8656 
8657 	if (__predict_false(SEQ_LEQ(th->th_ack, tp->snd_una))) {
8658 		/* Old ack, behind (or duplicate to) the last one rcv'd */
8659 		return (0);
8660 	}
8661 	if (__predict_false(SEQ_GT(th->th_ack, tp->snd_max))) {
8662 		/* Above what we have sent? */
8663 		return (0);
8664 	}
8665 	if (__predict_false(tiwin == 0)) {
8666 		/* zero window */
8667 		return (0);
8668 	}
8669 	if (__predict_false(tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN))) {
8670 		/* We need a SYN or a FIN, unlikely.. */
8671 		return (0);
8672 	}
8673 	if ((to->to_flags & TOF_TS) && __predict_false(TSTMP_LT(to->to_tsval, tp->ts_recent))) {
8674 		/* Timestamp is behind .. old ack with seq wrap? */
8675 		return (0);
8676 	}
8677 	if (__predict_false(IN_RECOVERY(tp->t_flags))) {
8678 		/* Still recovering */
8679 		return (0);
8680 	}
8681 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
8682 	if (__predict_false(bbr->r_ctl.rc_resend != NULL)) {
8683 		/* We are retransmitting */
8684 		return (0);
8685 	}
8686 	if (__predict_false(bbr->rc_in_persist != 0)) {
8687 		/* In persist mode */
8688 		return (0);
8689 	}
8690 	if (bbr->r_ctl.rc_sacked) {
8691 		/* We have sack holes on our scoreboard */
8692 		return (0);
8693 	}
8694 	/* Ok if we reach here, we can process a fast-ack */
8695 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
8696 	sack_changed = bbr_log_ack(tp, to, th, &prev_acked);
8697 	/*
8698 	 * We never detect loss in fast ack [we can't
8699 	 * have a sack and can't be in recovery so
8700 	 * we always pass 0 (nothing detected)].
8701 	 */
8702 	bbr_lt_bw_sampling(bbr, bbr->r_ctl.rc_rcvtime, 0);
8703 	/* Did the window get updated? */
8704 	if (tiwin != tp->snd_wnd) {
8705 		tp->snd_wnd = tiwin;
8706 		tp->snd_wl1 = th->th_seq;
8707 		if (tp->snd_wnd > tp->max_sndwnd)
8708 			tp->max_sndwnd = tp->snd_wnd;
8709 	}
8710 	/* Do we need to exit persists? */
8711 	if ((bbr->rc_in_persist != 0) &&
8712 	    (tp->snd_wnd >= min((bbr->r_ctl.rc_high_rwnd/2),
8713 			       bbr_minseg(bbr)))) {
8714 		bbr_exit_persist(tp, bbr, bbr->r_ctl.rc_rcvtime, __LINE__);
8715 		bbr->r_wanted_output = 1;
8716 	}
8717 	/* Do we need to enter persists? */
8718 	if ((bbr->rc_in_persist == 0) &&
8719 	    (tp->snd_wnd < min((bbr->r_ctl.rc_high_rwnd/2), bbr_minseg(bbr))) &&
8720 	    TCPS_HAVEESTABLISHED(tp->t_state) &&
8721 	    (tp->snd_max == tp->snd_una) &&
8722 	    sbavail(&tp->t_inpcb->inp_socket->so_snd) &&
8723 	    (sbavail(&tp->t_inpcb->inp_socket->so_snd) > tp->snd_wnd)) {
8724 		/* No send window.. we must enter persist */
8725 		bbr_enter_persist(tp, bbr, bbr->r_ctl.rc_rcvtime, __LINE__);
8726 	}
8727 	/*
8728 	 * If last ACK falls within this segment's sequence numbers, record
8729 	 * the timestamp. NOTE that the test is modified according to the
8730 	 * latest proposal of the tcplw@cray.com list (Braden 1993/04/26).
8731 	 */
8732 	if ((to->to_flags & TOF_TS) != 0 &&
8733 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
8734 		tp->ts_recent_age = bbr->r_ctl.rc_rcvtime;
8735 		tp->ts_recent = to->to_tsval;
8736 	}
8737 	/*
8738 	 * This is a pure ack for outstanding data.
8739 	 */
8740 	KMOD_TCPSTAT_INC(tcps_predack);
8741 
8742 	/*
8743 	 * "bad retransmit" recovery.
8744 	 */
8745 	if (tp->t_flags & TF_PREVVALID) {
8746 		tp->t_flags &= ~TF_PREVVALID;
8747 		if (tp->t_rxtshift == 1 &&
8748 		    (int)(ticks - tp->t_badrxtwin) < 0)
8749 			bbr_cong_signal(tp, th, CC_RTO_ERR, NULL);
8750 	}
8751 	/*
8752 	 * Recalculate the transmit timer / rtt.
8753 	 *
8754 	 * Some boxes send broken timestamp replies during the SYN+ACK
8755 	 * phase, ignore timestamps of 0 or we could calculate a huge RTT
8756 	 * and blow up the retransmit timer.
8757 	 */
8758 	acked = BYTES_THIS_ACK(tp, th);
8759 
8760 #ifdef TCP_HHOOK
8761 	/* Run HHOOK_TCP_ESTABLISHED_IN helper hooks. */
8762 	hhook_run_tcp_est_in(tp, th, to);
8763 #endif
8764 
8765 	KMOD_TCPSTAT_ADD(tcps_rcvackpack, (int)nsegs);
8766 	KMOD_TCPSTAT_ADD(tcps_rcvackbyte, acked);
8767 	sbdrop(&so->so_snd, acked);
8768 
8769 	if (SEQ_GT(th->th_ack, tp->snd_una))
8770 		bbr_collapse_rtt(tp, bbr, TCP_REXMTVAL(tp));
8771 	tp->snd_una = th->th_ack;
8772 	if (tp->snd_wnd < ctf_outstanding(tp))
8773 		/* The peer collapsed its window on us */
8774 		bbr_collapsed_window(bbr);
8775 	else if (bbr->rc_has_collapsed)
8776 		bbr_un_collapse_window(bbr);
8777 
8778 	if (SEQ_GT(tp->snd_una, tp->snd_recover)) {
8779 		tp->snd_recover = tp->snd_una;
8780 	}
8781 	bbr_ack_received(tp, bbr, th, acked, sack_changed, prev_acked, __LINE__, 0);
8782 	/*
8783 	 * Pull snd_wl2 up to prevent seq wrap relative to th_ack.
8784 	 */
8785 	tp->snd_wl2 = th->th_ack;
8786 	m_freem(m);
8787 	/*
8788 	 * If all outstanding data are acked, stop retransmit timer,
8789 	 * otherwise restart timer using current (possibly backed-off)
8790 	 * value. If process is waiting for space, wakeup/selwakeup/signal.
8791 	 * If data are ready to send, let tcp_output decide between more
8792 	 * output or persist.
8793 	 */
8794 #ifdef TCPDEBUG
8795 	if (so->so_options & SO_DEBUG)
8796 		tcp_trace(TA_INPUT, ostate, tp,
8797 		    (void *)tcp_saveipgen,
8798 		    &tcp_savetcp, 0);
8799 #endif
8800 	/* Wake up the socket if we have room to write more */
8801 	tp->t_flags |= TF_WAKESOW;
8802 	if (tp->snd_una == tp->snd_max) {
8803 		/* Nothing left outstanding */
8804 		bbr_log_progress_event(bbr, tp, ticks, PROGRESS_CLEAR, __LINE__);
8805 		if (sbavail(&tp->t_inpcb->inp_socket->so_snd) == 0)
8806 			bbr->rc_tp->t_acktime = 0;
8807 		bbr_timer_cancel(bbr, __LINE__, bbr->r_ctl.rc_rcvtime);
8808 		if (bbr->rc_in_persist == 0) {
8809 			bbr->r_ctl.rc_went_idle_time = bbr->r_ctl.rc_rcvtime;
8810 		}
8811 		sack_filter_clear(&bbr->r_ctl.bbr_sf, tp->snd_una);
8812 		bbr_log_ack_clear(bbr, bbr->r_ctl.rc_rcvtime);
8813 		/*
8814 		 * We invalidate the last ack here since we
8815 		 * don't want to transfer forward the time
8816 		 * for our sum's calculations.
8817 		 */
8818 		bbr->r_wanted_output = 1;
8819 	}
8820 	if (sbavail(&so->so_snd)) {
8821 		bbr->r_wanted_output = 1;
8822 	}
8823 	return (1);
8824 }
8825 
8826 /*
8827  * Return value of 1, the TCB is unlocked and most
8828  * likely gone, return value of 0, the TCB is still
8829  * locked.
8830  */
8831 static int
8832 bbr_do_syn_sent(struct mbuf *m, struct tcphdr *th, struct socket *so,
8833     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
8834     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
8835 {
8836 	int32_t todrop;
8837 	int32_t ourfinisacked = 0;
8838 	struct tcp_bbr *bbr;
8839 	int32_t ret_val = 0;
8840 
8841 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
8842 	ctf_calc_rwin(so, tp);
8843 	/*
8844 	 * If the state is SYN_SENT: if seg contains an ACK, but not for our
8845 	 * SYN, drop the input. if seg contains a RST, then drop the
8846 	 * connection. if seg does not contain SYN, then drop it. Otherwise
8847 	 * this is an acceptable SYN segment initialize tp->rcv_nxt and
8848 	 * tp->irs if seg contains ack then advance tp->snd_una. BRR does
8849 	 * not support ECN so we will not say we are capable. if SYN has
8850 	 * been acked change to ESTABLISHED else SYN_RCVD state arrange for
8851 	 * segment to be acked (eventually) continue processing rest of
8852 	 * data/controls, beginning with URG
8853 	 */
8854 	if ((thflags & TH_ACK) &&
8855 	    (SEQ_LEQ(th->th_ack, tp->iss) ||
8856 	    SEQ_GT(th->th_ack, tp->snd_max))) {
8857 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
8858 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
8859 		return (1);
8860 	}
8861 	if ((thflags & (TH_ACK | TH_RST)) == (TH_ACK | TH_RST)) {
8862 		TCP_PROBE5(connect__refused, NULL, tp,
8863 		    mtod(m, const char *), tp, th);
8864 		tp = tcp_drop(tp, ECONNREFUSED);
8865 		ctf_do_drop(m, tp);
8866 		return (1);
8867 	}
8868 	if (thflags & TH_RST) {
8869 		ctf_do_drop(m, tp);
8870 		return (1);
8871 	}
8872 	if (!(thflags & TH_SYN)) {
8873 		ctf_do_drop(m, tp);
8874 		return (1);
8875 	}
8876 	tp->irs = th->th_seq;
8877 	tcp_rcvseqinit(tp);
8878 	if (thflags & TH_ACK) {
8879 		int tfo_partial = 0;
8880 
8881 		KMOD_TCPSTAT_INC(tcps_connects);
8882 		soisconnected(so);
8883 #ifdef MAC
8884 		mac_socketpeer_set_from_mbuf(m, so);
8885 #endif
8886 		/* Do window scaling on this connection? */
8887 		if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
8888 		    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
8889 			tp->rcv_scale = tp->request_r_scale;
8890 		}
8891 		tp->rcv_adv += min(tp->rcv_wnd,
8892 		    TCP_MAXWIN << tp->rcv_scale);
8893 		/*
8894 		 * If not all the data that was sent in the TFO SYN
8895 		 * has been acked, resend the remainder right away.
8896 		 */
8897 		if (IS_FASTOPEN(tp->t_flags) &&
8898 		    (tp->snd_una != tp->snd_max)) {
8899 			tp->snd_nxt = th->th_ack;
8900 			tfo_partial = 1;
8901 		}
8902 		/*
8903 		 * If there's data, delay ACK; if there's also a FIN ACKNOW
8904 		 * will be turned on later.
8905 		 */
8906 		if (DELAY_ACK(tp, bbr, 1) && tlen != 0 && !tfo_partial) {
8907 			bbr->bbr_segs_rcvd += 1;
8908 			tp->t_flags |= TF_DELACK;
8909 			bbr_timer_cancel(bbr, __LINE__, bbr->r_ctl.rc_rcvtime);
8910 		} else {
8911 			bbr->r_wanted_output = 1;
8912 			tp->t_flags |= TF_ACKNOW;
8913 		}
8914 		if (SEQ_GT(th->th_ack, tp->iss)) {
8915 			/*
8916 			 * The SYN is acked
8917 			 * handle it specially.
8918 			 */
8919 			bbr_log_syn(tp, to);
8920 		}
8921 		if (SEQ_GT(th->th_ack, tp->snd_una)) {
8922 			/*
8923 			 * We advance snd_una for the
8924 			 * fast open case. If th_ack is
8925 			 * acknowledging data beyond
8926 			 * snd_una we can't just call
8927 			 * ack-processing since the
8928 			 * data stream in our send-map
8929 			 * will start at snd_una + 1 (one
8930 			 * beyond the SYN). If its just
8931 			 * equal we don't need to do that
8932 			 * and there is no send_map.
8933 			 */
8934 			tp->snd_una++;
8935 		}
8936 		/*
8937 		 * Received <SYN,ACK> in SYN_SENT[*] state. Transitions:
8938 		 * SYN_SENT  --> ESTABLISHED SYN_SENT* --> FIN_WAIT_1
8939 		 */
8940 		tp->t_starttime = ticks;
8941 		if (tp->t_flags & TF_NEEDFIN) {
8942 			tcp_state_change(tp, TCPS_FIN_WAIT_1);
8943 			tp->t_flags &= ~TF_NEEDFIN;
8944 			thflags &= ~TH_SYN;
8945 		} else {
8946 			tcp_state_change(tp, TCPS_ESTABLISHED);
8947 			TCP_PROBE5(connect__established, NULL, tp,
8948 			    mtod(m, const char *), tp, th);
8949 			cc_conn_init(tp);
8950 		}
8951 	} else {
8952 		/*
8953 		 * Received initial SYN in SYN-SENT[*] state => simultaneous
8954 		 * open.  If segment contains CC option and there is a
8955 		 * cached CC, apply TAO test. If it succeeds, connection is *
8956 		 * half-synchronized. Otherwise, do 3-way handshake:
8957 		 * SYN-SENT -> SYN-RECEIVED SYN-SENT* -> SYN-RECEIVED* If
8958 		 * there was no CC option, clear cached CC value.
8959 		 */
8960 		tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
8961 		tcp_state_change(tp, TCPS_SYN_RECEIVED);
8962 	}
8963 	INP_WLOCK_ASSERT(tp->t_inpcb);
8964 	/*
8965 	 * Advance th->th_seq to correspond to first data byte. If data,
8966 	 * trim to stay within window, dropping FIN if necessary.
8967 	 */
8968 	th->th_seq++;
8969 	if (tlen > tp->rcv_wnd) {
8970 		todrop = tlen - tp->rcv_wnd;
8971 		m_adj(m, -todrop);
8972 		tlen = tp->rcv_wnd;
8973 		thflags &= ~TH_FIN;
8974 		KMOD_TCPSTAT_INC(tcps_rcvpackafterwin);
8975 		KMOD_TCPSTAT_ADD(tcps_rcvbyteafterwin, todrop);
8976 	}
8977 	tp->snd_wl1 = th->th_seq - 1;
8978 	tp->rcv_up = th->th_seq;
8979 	/*
8980 	 * Client side of transaction: already sent SYN and data. If the
8981 	 * remote host used T/TCP to validate the SYN, our data will be
8982 	 * ACK'd; if so, enter normal data segment processing in the middle
8983 	 * of step 5, ack processing. Otherwise, goto step 6.
8984 	 */
8985 	if (thflags & TH_ACK) {
8986 		if ((to->to_flags & TOF_TS) != 0) {
8987 			uint32_t t, rtt;
8988 
8989 			t = tcp_tv_to_mssectick(&bbr->rc_tv);
8990 			if (TSTMP_GEQ(t, to->to_tsecr)) {
8991 				rtt = t - to->to_tsecr;
8992 				if (rtt == 0) {
8993 					rtt = 1;
8994 				}
8995 				rtt *= MS_IN_USEC;
8996 				tcp_bbr_xmit_timer(bbr, rtt, 0, 0, 0);
8997 				apply_filter_min_small(&bbr->r_ctl.rc_rttprop,
8998 						       rtt, bbr->r_ctl.rc_rcvtime);
8999 			}
9000 		}
9001 		if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val))
9002 			return (ret_val);
9003 		/* We may have changed to FIN_WAIT_1 above */
9004 		if (tp->t_state == TCPS_FIN_WAIT_1) {
9005 			/*
9006 			 * In FIN_WAIT_1 STATE in addition to the processing
9007 			 * for the ESTABLISHED state if our FIN is now
9008 			 * acknowledged then enter FIN_WAIT_2.
9009 			 */
9010 			if (ourfinisacked) {
9011 				/*
9012 				 * If we can't receive any more data, then
9013 				 * closing user can proceed. Starting the
9014 				 * timer is contrary to the specification,
9015 				 * but if we don't get a FIN we'll hang
9016 				 * forever.
9017 				 *
9018 				 * XXXjl: we should release the tp also, and
9019 				 * use a compressed state.
9020 				 */
9021 				if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
9022 					soisdisconnected(so);
9023 					tcp_timer_activate(tp, TT_2MSL,
9024 					    (tcp_fast_finwait2_recycle ?
9025 					    tcp_finwait2_timeout :
9026 					    TP_MAXIDLE(tp)));
9027 				}
9028 				tcp_state_change(tp, TCPS_FIN_WAIT_2);
9029 			}
9030 		}
9031 	}
9032 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9033 	    tiwin, thflags, nxt_pkt));
9034 }
9035 
9036 /*
9037  * Return value of 1, the TCB is unlocked and most
9038  * likely gone, return value of 0, the TCB is still
9039  * locked.
9040  */
9041 static int
9042 bbr_do_syn_recv(struct mbuf *m, struct tcphdr *th, struct socket *so,
9043 		struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9044 		uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9045 {
9046 	int32_t ourfinisacked = 0;
9047 	int32_t ret_val;
9048 	struct tcp_bbr *bbr;
9049 
9050 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9051 	ctf_calc_rwin(so, tp);
9052 	if ((thflags & TH_ACK) &&
9053 	    (SEQ_LEQ(th->th_ack, tp->snd_una) ||
9054 	     SEQ_GT(th->th_ack, tp->snd_max))) {
9055 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
9056 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9057 		return (1);
9058 	}
9059 	if (IS_FASTOPEN(tp->t_flags)) {
9060 		/*
9061 		 * When a TFO connection is in SYN_RECEIVED, the only valid
9062 		 * packets are the initial SYN, a retransmit/copy of the
9063 		 * initial SYN (possibly with a subset of the original
9064 		 * data), a valid ACK, a FIN, or a RST.
9065 		 */
9066 		if ((thflags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) {
9067 			tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
9068 			ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9069 			return (1);
9070 		} else if (thflags & TH_SYN) {
9071 			/* non-initial SYN is ignored */
9072 			if ((bbr->r_ctl.rc_hpts_flags & PACE_TMR_RXT) ||
9073 			    (bbr->r_ctl.rc_hpts_flags & PACE_TMR_TLP) ||
9074 			    (bbr->r_ctl.rc_hpts_flags & PACE_TMR_RACK)) {
9075 				ctf_do_drop(m, NULL);
9076 				return (0);
9077 			}
9078 		} else if (!(thflags & (TH_ACK | TH_FIN | TH_RST))) {
9079 			ctf_do_drop(m, NULL);
9080 			return (0);
9081 		}
9082 	}
9083 	if ((thflags & TH_RST) ||
9084 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9085 		return (ctf_process_rst(m, th, so, tp));
9086 	/*
9087 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9088 	 * it's less than ts_recent, drop it.
9089 	 */
9090 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9091 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9092 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9093 			return (ret_val);
9094 	}
9095 	/*
9096 	 * In the SYN-RECEIVED state, validate that the packet belongs to
9097 	 * this connection before trimming the data to fit the receive
9098 	 * window.  Check the sequence number versus IRS since we know the
9099 	 * sequence numbers haven't wrapped.  This is a partial fix for the
9100 	 * "LAND" DoS attack.
9101 	 */
9102 	if (SEQ_LT(th->th_seq, tp->irs)) {
9103 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
9104 		ctf_do_dropwithreset(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9105 		return (1);
9106 	}
9107 	INP_WLOCK_ASSERT(tp->t_inpcb);
9108 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9109 		return (ret_val);
9110 	}
9111 	/*
9112 	 * If last ACK falls within this segment's sequence numbers, record
9113 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9114 	 * from the latest proposal of the tcplw@cray.com list (Braden
9115 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9116 	 * with our earlier PAWS tests, so this check should be solely
9117 	 * predicated on the sequence space of this segment. 3) That we
9118 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9119 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9120 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9121 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9122 	 * p.869. In such cases, we can still calculate the RTT correctly
9123 	 * when RCV.NXT == Last.ACK.Sent.
9124 	 */
9125 	if ((to->to_flags & TOF_TS) != 0 &&
9126 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9127 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9128 		    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9129 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9130 		tp->ts_recent = to->to_tsval;
9131 	}
9132 	tp->snd_wnd = tiwin;
9133 	/*
9134 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9135 	 * is on (half-synchronized state), then queue data for later
9136 	 * processing; else drop segment and return.
9137 	 */
9138 	if ((thflags & TH_ACK) == 0) {
9139 		if (IS_FASTOPEN(tp->t_flags)) {
9140 			cc_conn_init(tp);
9141 		}
9142 		return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9143 					 tiwin, thflags, nxt_pkt));
9144 	}
9145 	KMOD_TCPSTAT_INC(tcps_connects);
9146 	soisconnected(so);
9147 	/* Do window scaling? */
9148 	if ((tp->t_flags & (TF_RCVD_SCALE | TF_REQ_SCALE)) ==
9149 	    (TF_RCVD_SCALE | TF_REQ_SCALE)) {
9150 		tp->rcv_scale = tp->request_r_scale;
9151 	}
9152 	/*
9153 	 * ok for the first time in lets see if we can use the ts to figure
9154 	 * out what the initial RTT was.
9155 	 */
9156 	if ((to->to_flags & TOF_TS) != 0) {
9157 		uint32_t t, rtt;
9158 
9159 		t = tcp_tv_to_mssectick(&bbr->rc_tv);
9160 		if (TSTMP_GEQ(t, to->to_tsecr)) {
9161 			rtt = t - to->to_tsecr;
9162 			if (rtt == 0) {
9163 				rtt = 1;
9164 			}
9165 			rtt *= MS_IN_USEC;
9166 			tcp_bbr_xmit_timer(bbr, rtt, 0, 0, 0);
9167 			apply_filter_min_small(&bbr->r_ctl.rc_rttprop, rtt, bbr->r_ctl.rc_rcvtime);
9168 		}
9169 	}
9170 	/* Drop off any SYN in the send map (probably not there)  */
9171 	if (thflags & TH_ACK)
9172 		bbr_log_syn(tp, to);
9173 	if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) {
9174 		tcp_fastopen_decrement_counter(tp->t_tfo_pending);
9175 		tp->t_tfo_pending = NULL;
9176 	}
9177 	/*
9178 	 * Make transitions: SYN-RECEIVED  -> ESTABLISHED SYN-RECEIVED* ->
9179 	 * FIN-WAIT-1
9180 	 */
9181 	tp->t_starttime = ticks;
9182 	if (tp->t_flags & TF_NEEDFIN) {
9183 		tcp_state_change(tp, TCPS_FIN_WAIT_1);
9184 		tp->t_flags &= ~TF_NEEDFIN;
9185 	} else {
9186 		tcp_state_change(tp, TCPS_ESTABLISHED);
9187 		TCP_PROBE5(accept__established, NULL, tp,
9188 			   mtod(m, const char *), tp, th);
9189 		/*
9190 		 * TFO connections call cc_conn_init() during SYN
9191 		 * processing.  Calling it again here for such connections
9192 		 * is not harmless as it would undo the snd_cwnd reduction
9193 		 * that occurs when a TFO SYN|ACK is retransmitted.
9194 		 */
9195 		if (!IS_FASTOPEN(tp->t_flags))
9196 			cc_conn_init(tp);
9197 	}
9198 	/*
9199 	 * Account for the ACK of our SYN prior to
9200 	 * regular ACK processing below, except for
9201 	 * simultaneous SYN, which is handled later.
9202 	 */
9203 	if (SEQ_GT(th->th_ack, tp->snd_una) && !(tp->t_flags & TF_NEEDSYN))
9204 		tp->snd_una++;
9205 	/*
9206 	 * If segment contains data or ACK, will call tcp_reass() later; if
9207 	 * not, do so now to pass queued data to user.
9208 	 */
9209 	if (tlen == 0 && (thflags & TH_FIN) == 0)
9210 		(void)tcp_reass(tp, (struct tcphdr *)0, NULL, 0,
9211 			(struct mbuf *)0);
9212 	tp->snd_wl1 = th->th_seq - 1;
9213 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
9214 		return (ret_val);
9215 	}
9216 	if (tp->t_state == TCPS_FIN_WAIT_1) {
9217 		/* We could have went to FIN_WAIT_1 (or EST) above */
9218 		/*
9219 		 * In FIN_WAIT_1 STATE in addition to the processing for the
9220 		 * ESTABLISHED state if our FIN is now acknowledged then
9221 		 * enter FIN_WAIT_2.
9222 		 */
9223 		if (ourfinisacked) {
9224 			/*
9225 			 * If we can't receive any more data, then closing
9226 			 * user can proceed. Starting the timer is contrary
9227 			 * to the specification, but if we don't get a FIN
9228 			 * we'll hang forever.
9229 			 *
9230 			 * XXXjl: we should release the tp also, and use a
9231 			 * compressed state.
9232 			 */
9233 			if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
9234 				soisdisconnected(so);
9235 				tcp_timer_activate(tp, TT_2MSL,
9236 						   (tcp_fast_finwait2_recycle ?
9237 						    tcp_finwait2_timeout :
9238 						    TP_MAXIDLE(tp)));
9239 			}
9240 			tcp_state_change(tp, TCPS_FIN_WAIT_2);
9241 		}
9242 	}
9243 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9244 				 tiwin, thflags, nxt_pkt));
9245 }
9246 
9247 /*
9248  * Return value of 1, the TCB is unlocked and most
9249  * likely gone, return value of 0, the TCB is still
9250  * locked.
9251  */
9252 static int
9253 bbr_do_established(struct mbuf *m, struct tcphdr *th, struct socket *so,
9254     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9255     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9256 {
9257 	struct tcp_bbr *bbr;
9258 	int32_t ret_val;
9259 
9260 	/*
9261 	 * Header prediction: check for the two common cases of a
9262 	 * uni-directional data xfer.  If the packet has no control flags,
9263 	 * is in-sequence, the window didn't change and we're not
9264 	 * retransmitting, it's a candidate.  If the length is zero and the
9265 	 * ack moved forward, we're the sender side of the xfer.  Just free
9266 	 * the data acked & wake any higher level process that was blocked
9267 	 * waiting for space.  If the length is non-zero and the ack didn't
9268 	 * move, we're the receiver side.  If we're getting packets in-order
9269 	 * (the reassembly queue is empty), add the data toc The socket
9270 	 * buffer and note that we need a delayed ack. Make sure that the
9271 	 * hidden state-flags are also off. Since we check for
9272 	 * TCPS_ESTABLISHED first, it can only be TH_NEEDSYN.
9273 	 */
9274 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9275 	if (bbr->r_ctl.rc_delivered < (4 * tp->t_maxseg)) {
9276 		/*
9277 		 * If we have delived under 4 segments increase the initial
9278 		 * window if raised by the peer. We use this to determine
9279 		 * dynamic and static rwnd's at the end of a connection.
9280 		 */
9281 		bbr->r_ctl.rc_init_rwnd = max(tiwin, tp->snd_wnd);
9282 	}
9283 	if (__predict_true(((to->to_flags & TOF_SACK) == 0)) &&
9284 	    __predict_true((thflags & (TH_SYN | TH_FIN | TH_RST | TH_URG | TH_ACK)) == TH_ACK) &&
9285 	    __predict_true(SEGQ_EMPTY(tp)) &&
9286 	    __predict_true(th->th_seq == tp->rcv_nxt)) {
9287 		if (tlen == 0) {
9288 			if (bbr_fastack(m, th, so, tp, to, drop_hdrlen, tlen,
9289 			    tiwin, nxt_pkt, iptos)) {
9290 				return (0);
9291 			}
9292 		} else {
9293 			if (bbr_do_fastnewdata(m, th, so, tp, to, drop_hdrlen, tlen,
9294 			    tiwin, nxt_pkt)) {
9295 				return (0);
9296 			}
9297 		}
9298 	}
9299 	ctf_calc_rwin(so, tp);
9300 
9301 	if ((thflags & TH_RST) ||
9302 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9303 		return (ctf_process_rst(m, th, so, tp));
9304 	/*
9305 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9306 	 * synchronized state.
9307 	 */
9308 	if (thflags & TH_SYN) {
9309 		ctf_challenge_ack(m, th, tp, &ret_val);
9310 		return (ret_val);
9311 	}
9312 	/*
9313 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9314 	 * it's less than ts_recent, drop it.
9315 	 */
9316 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9317 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9318 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9319 			return (ret_val);
9320 	}
9321 	INP_WLOCK_ASSERT(tp->t_inpcb);
9322 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9323 		return (ret_val);
9324 	}
9325 	/*
9326 	 * If last ACK falls within this segment's sequence numbers, record
9327 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9328 	 * from the latest proposal of the tcplw@cray.com list (Braden
9329 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9330 	 * with our earlier PAWS tests, so this check should be solely
9331 	 * predicated on the sequence space of this segment. 3) That we
9332 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9333 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9334 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9335 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9336 	 * p.869. In such cases, we can still calculate the RTT correctly
9337 	 * when RCV.NXT == Last.ACK.Sent.
9338 	 */
9339 	if ((to->to_flags & TOF_TS) != 0 &&
9340 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9341 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9342 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9343 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9344 		tp->ts_recent = to->to_tsval;
9345 	}
9346 	/*
9347 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9348 	 * is on (half-synchronized state), then queue data for later
9349 	 * processing; else drop segment and return.
9350 	 */
9351 	if ((thflags & TH_ACK) == 0) {
9352 		if (tp->t_flags & TF_NEEDSYN) {
9353 			return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9354 			    tiwin, thflags, nxt_pkt));
9355 		} else if (tp->t_flags & TF_ACKNOW) {
9356 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9357 			bbr->r_wanted_output = 1;
9358 			return (ret_val);
9359 		} else {
9360 			ctf_do_drop(m, NULL);
9361 			return (0);
9362 		}
9363 	}
9364 	/*
9365 	 * Ack processing.
9366 	 */
9367 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) {
9368 		return (ret_val);
9369 	}
9370 	if (sbavail(&so->so_snd)) {
9371 		if (ctf_progress_timeout_check(tp, true)) {
9372 			bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP, __LINE__);
9373 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9374 			return (1);
9375 		}
9376 	}
9377 	/* State changes only happen in bbr_process_data() */
9378 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9379 	    tiwin, thflags, nxt_pkt));
9380 }
9381 
9382 /*
9383  * Return value of 1, the TCB is unlocked and most
9384  * likely gone, return value of 0, the TCB is still
9385  * locked.
9386  */
9387 static int
9388 bbr_do_close_wait(struct mbuf *m, struct tcphdr *th, struct socket *so,
9389     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9390     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9391 {
9392 	struct tcp_bbr *bbr;
9393 	int32_t ret_val;
9394 
9395 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9396 	ctf_calc_rwin(so, tp);
9397 	if ((thflags & TH_RST) ||
9398 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9399 		return (ctf_process_rst(m, th, so, tp));
9400 	/*
9401 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9402 	 * synchronized state.
9403 	 */
9404 	if (thflags & TH_SYN) {
9405 		ctf_challenge_ack(m, th, tp, &ret_val);
9406 		return (ret_val);
9407 	}
9408 	/*
9409 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9410 	 * it's less than ts_recent, drop it.
9411 	 */
9412 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9413 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9414 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9415 			return (ret_val);
9416 	}
9417 	INP_WLOCK_ASSERT(tp->t_inpcb);
9418 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9419 		return (ret_val);
9420 	}
9421 	/*
9422 	 * If last ACK falls within this segment's sequence numbers, record
9423 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9424 	 * from the latest proposal of the tcplw@cray.com list (Braden
9425 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9426 	 * with our earlier PAWS tests, so this check should be solely
9427 	 * predicated on the sequence space of this segment. 3) That we
9428 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9429 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9430 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9431 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9432 	 * p.869. In such cases, we can still calculate the RTT correctly
9433 	 * when RCV.NXT == Last.ACK.Sent.
9434 	 */
9435 	if ((to->to_flags & TOF_TS) != 0 &&
9436 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9437 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9438 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9439 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9440 		tp->ts_recent = to->to_tsval;
9441 	}
9442 	/*
9443 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9444 	 * is on (half-synchronized state), then queue data for later
9445 	 * processing; else drop segment and return.
9446 	 */
9447 	if ((thflags & TH_ACK) == 0) {
9448 		if (tp->t_flags & TF_NEEDSYN) {
9449 			return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9450 			    tiwin, thflags, nxt_pkt));
9451 		} else if (tp->t_flags & TF_ACKNOW) {
9452 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9453 			bbr->r_wanted_output = 1;
9454 			return (ret_val);
9455 		} else {
9456 			ctf_do_drop(m, NULL);
9457 			return (0);
9458 		}
9459 	}
9460 	/*
9461 	 * Ack processing.
9462 	 */
9463 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, NULL, thflags, &ret_val)) {
9464 		return (ret_val);
9465 	}
9466 	if (sbavail(&so->so_snd)) {
9467 		if (ctf_progress_timeout_check(tp, true)) {
9468 			bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP, __LINE__);
9469 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9470 			return (1);
9471 		}
9472 	}
9473 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9474 	    tiwin, thflags, nxt_pkt));
9475 }
9476 
9477 static int
9478 bbr_check_data_after_close(struct mbuf *m, struct tcp_bbr *bbr,
9479     struct tcpcb *tp, int32_t * tlen, struct tcphdr *th, struct socket *so)
9480 {
9481 
9482 	if (bbr->rc_allow_data_af_clo == 0) {
9483 close_now:
9484 		tcp_log_end_status(tp, TCP_EI_STATUS_DATA_A_CLOSE);
9485 		/* tcp_close will kill the inp pre-log the Reset */
9486 		tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
9487 		tp = tcp_close(tp);
9488 		KMOD_TCPSTAT_INC(tcps_rcvafterclose);
9489 		ctf_do_dropwithreset(m, tp, th, BANDLIM_UNLIMITED, (*tlen));
9490 		return (1);
9491 	}
9492 	if (sbavail(&so->so_snd) == 0)
9493 		goto close_now;
9494 	/* Ok we allow data that is ignored and a followup reset */
9495 	tp->rcv_nxt = th->th_seq + *tlen;
9496 	tp->t_flags2 |= TF2_DROP_AF_DATA;
9497 	bbr->r_wanted_output = 1;
9498 	*tlen = 0;
9499 	return (0);
9500 }
9501 
9502 /*
9503  * Return value of 1, the TCB is unlocked and most
9504  * likely gone, return value of 0, the TCB is still
9505  * locked.
9506  */
9507 static int
9508 bbr_do_fin_wait_1(struct mbuf *m, struct tcphdr *th, struct socket *so,
9509     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9510     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9511 {
9512 	int32_t ourfinisacked = 0;
9513 	int32_t ret_val;
9514 	struct tcp_bbr *bbr;
9515 
9516 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9517 	ctf_calc_rwin(so, tp);
9518 	if ((thflags & TH_RST) ||
9519 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9520 		return (ctf_process_rst(m, th, so, tp));
9521 	/*
9522 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9523 	 * synchronized state.
9524 	 */
9525 	if (thflags & TH_SYN) {
9526 		ctf_challenge_ack(m, th, tp, &ret_val);
9527 		return (ret_val);
9528 	}
9529 	/*
9530 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9531 	 * it's less than ts_recent, drop it.
9532 	 */
9533 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9534 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9535 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9536 			return (ret_val);
9537 	}
9538 	INP_WLOCK_ASSERT(tp->t_inpcb);
9539 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9540 		return (ret_val);
9541 	}
9542 	/*
9543 	 * If new data are received on a connection after the user processes
9544 	 * are gone, then RST the other end.
9545 	 */
9546 	if ((so->so_state & SS_NOFDREF) && tlen) {
9547 		/*
9548 		 * We call a new function now so we might continue and setup
9549 		 * to reset at all data being ack'd.
9550 		 */
9551 		if (bbr_check_data_after_close(m, bbr, tp, &tlen, th, so))
9552 			return (1);
9553 	}
9554 	/*
9555 	 * If last ACK falls within this segment's sequence numbers, record
9556 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9557 	 * from the latest proposal of the tcplw@cray.com list (Braden
9558 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9559 	 * with our earlier PAWS tests, so this check should be solely
9560 	 * predicated on the sequence space of this segment. 3) That we
9561 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9562 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9563 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9564 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9565 	 * p.869. In such cases, we can still calculate the RTT correctly
9566 	 * when RCV.NXT == Last.ACK.Sent.
9567 	 */
9568 	if ((to->to_flags & TOF_TS) != 0 &&
9569 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9570 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9571 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9572 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9573 		tp->ts_recent = to->to_tsval;
9574 	}
9575 	/*
9576 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9577 	 * is on (half-synchronized state), then queue data for later
9578 	 * processing; else drop segment and return.
9579 	 */
9580 	if ((thflags & TH_ACK) == 0) {
9581 		if (tp->t_flags & TF_NEEDSYN) {
9582 			return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9583 			    tiwin, thflags, nxt_pkt));
9584 		} else if (tp->t_flags & TF_ACKNOW) {
9585 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9586 			bbr->r_wanted_output = 1;
9587 			return (ret_val);
9588 		} else {
9589 			ctf_do_drop(m, NULL);
9590 			return (0);
9591 		}
9592 	}
9593 	/*
9594 	 * Ack processing.
9595 	 */
9596 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
9597 		return (ret_val);
9598 	}
9599 	if (ourfinisacked) {
9600 		/*
9601 		 * If we can't receive any more data, then closing user can
9602 		 * proceed. Starting the timer is contrary to the
9603 		 * specification, but if we don't get a FIN we'll hang
9604 		 * forever.
9605 		 *
9606 		 * XXXjl: we should release the tp also, and use a
9607 		 * compressed state.
9608 		 */
9609 		if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
9610 			soisdisconnected(so);
9611 			tcp_timer_activate(tp, TT_2MSL,
9612 			    (tcp_fast_finwait2_recycle ?
9613 			    tcp_finwait2_timeout :
9614 			    TP_MAXIDLE(tp)));
9615 		}
9616 		tcp_state_change(tp, TCPS_FIN_WAIT_2);
9617 	}
9618 	if (sbavail(&so->so_snd)) {
9619 		if (ctf_progress_timeout_check(tp, true)) {
9620 			bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP, __LINE__);
9621 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9622 			return (1);
9623 		}
9624 	}
9625 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9626 	    tiwin, thflags, nxt_pkt));
9627 }
9628 
9629 /*
9630  * Return value of 1, the TCB is unlocked and most
9631  * likely gone, return value of 0, the TCB is still
9632  * locked.
9633  */
9634 static int
9635 bbr_do_closing(struct mbuf *m, struct tcphdr *th, struct socket *so,
9636     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9637     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9638 {
9639 	int32_t ourfinisacked = 0;
9640 	int32_t ret_val;
9641 	struct tcp_bbr *bbr;
9642 
9643 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9644 	ctf_calc_rwin(so, tp);
9645 	if ((thflags & TH_RST) ||
9646 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9647 		return (ctf_process_rst(m, th, so, tp));
9648 	/*
9649 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9650 	 * synchronized state.
9651 	 */
9652 	if (thflags & TH_SYN) {
9653 		ctf_challenge_ack(m, th, tp, &ret_val);
9654 		return (ret_val);
9655 	}
9656 	/*
9657 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9658 	 * it's less than ts_recent, drop it.
9659 	 */
9660 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9661 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9662 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9663 			return (ret_val);
9664 	}
9665 	INP_WLOCK_ASSERT(tp->t_inpcb);
9666 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9667 		return (ret_val);
9668 	}
9669 	/*
9670 	 * If new data are received on a connection after the user processes
9671 	 * are gone, then RST the other end.
9672 	 */
9673 	if ((so->so_state & SS_NOFDREF) && tlen) {
9674 		/*
9675 		 * We call a new function now so we might continue and setup
9676 		 * to reset at all data being ack'd.
9677 		 */
9678 		if (bbr_check_data_after_close(m, bbr, tp, &tlen, th, so))
9679 			return (1);
9680 	}
9681 	/*
9682 	 * If last ACK falls within this segment's sequence numbers, record
9683 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9684 	 * from the latest proposal of the tcplw@cray.com list (Braden
9685 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9686 	 * with our earlier PAWS tests, so this check should be solely
9687 	 * predicated on the sequence space of this segment. 3) That we
9688 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9689 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9690 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9691 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9692 	 * p.869. In such cases, we can still calculate the RTT correctly
9693 	 * when RCV.NXT == Last.ACK.Sent.
9694 	 */
9695 	if ((to->to_flags & TOF_TS) != 0 &&
9696 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9697 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9698 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9699 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9700 		tp->ts_recent = to->to_tsval;
9701 	}
9702 	/*
9703 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9704 	 * is on (half-synchronized state), then queue data for later
9705 	 * processing; else drop segment and return.
9706 	 */
9707 	if ((thflags & TH_ACK) == 0) {
9708 		if (tp->t_flags & TF_NEEDSYN) {
9709 			return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9710 			    tiwin, thflags, nxt_pkt));
9711 		} else if (tp->t_flags & TF_ACKNOW) {
9712 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9713 			bbr->r_wanted_output = 1;
9714 			return (ret_val);
9715 		} else {
9716 			ctf_do_drop(m, NULL);
9717 			return (0);
9718 		}
9719 	}
9720 	/*
9721 	 * Ack processing.
9722 	 */
9723 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
9724 		return (ret_val);
9725 	}
9726 	if (ourfinisacked) {
9727 		tcp_twstart(tp);
9728 		m_freem(m);
9729 		return (1);
9730 	}
9731 	if (sbavail(&so->so_snd)) {
9732 		if (ctf_progress_timeout_check(tp, true)) {
9733 			bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP, __LINE__);
9734 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9735 			return (1);
9736 		}
9737 	}
9738 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9739 	    tiwin, thflags, nxt_pkt));
9740 }
9741 
9742 /*
9743  * Return value of 1, the TCB is unlocked and most
9744  * likely gone, return value of 0, the TCB is still
9745  * locked.
9746  */
9747 static int
9748 bbr_do_lastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
9749     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9750     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9751 {
9752 	int32_t ourfinisacked = 0;
9753 	int32_t ret_val;
9754 	struct tcp_bbr *bbr;
9755 
9756 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9757 	ctf_calc_rwin(so, tp);
9758 	if ((thflags & TH_RST) ||
9759 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9760 		return (ctf_process_rst(m, th, so, tp));
9761 	/*
9762 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9763 	 * synchronized state.
9764 	 */
9765 	if (thflags & TH_SYN) {
9766 		ctf_challenge_ack(m, th, tp, &ret_val);
9767 		return (ret_val);
9768 	}
9769 	/*
9770 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9771 	 * it's less than ts_recent, drop it.
9772 	 */
9773 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9774 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9775 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9776 			return (ret_val);
9777 	}
9778 	INP_WLOCK_ASSERT(tp->t_inpcb);
9779 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9780 		return (ret_val);
9781 	}
9782 	/*
9783 	 * If new data are received on a connection after the user processes
9784 	 * are gone, then RST the other end.
9785 	 */
9786 	if ((so->so_state & SS_NOFDREF) && tlen) {
9787 		/*
9788 		 * We call a new function now so we might continue and setup
9789 		 * to reset at all data being ack'd.
9790 		 */
9791 		if (bbr_check_data_after_close(m, bbr, tp, &tlen, th, so))
9792 			return (1);
9793 	}
9794 	/*
9795 	 * If last ACK falls within this segment's sequence numbers, record
9796 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9797 	 * from the latest proposal of the tcplw@cray.com list (Braden
9798 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9799 	 * with our earlier PAWS tests, so this check should be solely
9800 	 * predicated on the sequence space of this segment. 3) That we
9801 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9802 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9803 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9804 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9805 	 * p.869. In such cases, we can still calculate the RTT correctly
9806 	 * when RCV.NXT == Last.ACK.Sent.
9807 	 */
9808 	if ((to->to_flags & TOF_TS) != 0 &&
9809 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9810 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9811 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9812 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9813 		tp->ts_recent = to->to_tsval;
9814 	}
9815 	/*
9816 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9817 	 * is on (half-synchronized state), then queue data for later
9818 	 * processing; else drop segment and return.
9819 	 */
9820 	if ((thflags & TH_ACK) == 0) {
9821 		if (tp->t_flags & TF_NEEDSYN) {
9822 			return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9823 			    tiwin, thflags, nxt_pkt));
9824 		} else if (tp->t_flags & TF_ACKNOW) {
9825 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9826 			bbr->r_wanted_output = 1;
9827 			return (ret_val);
9828 		} else {
9829 			ctf_do_drop(m, NULL);
9830 			return (0);
9831 		}
9832 	}
9833 	/*
9834 	 * case TCPS_LAST_ACK: Ack processing.
9835 	 */
9836 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
9837 		return (ret_val);
9838 	}
9839 	if (ourfinisacked) {
9840 		tp = tcp_close(tp);
9841 		ctf_do_drop(m, tp);
9842 		return (1);
9843 	}
9844 	if (sbavail(&so->so_snd)) {
9845 		if (ctf_progress_timeout_check(tp, true)) {
9846 			bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP, __LINE__);
9847 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9848 			return (1);
9849 		}
9850 	}
9851 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9852 	    tiwin, thflags, nxt_pkt));
9853 }
9854 
9855 /*
9856  * Return value of 1, the TCB is unlocked and most
9857  * likely gone, return value of 0, the TCB is still
9858  * locked.
9859  */
9860 static int
9861 bbr_do_fin_wait_2(struct mbuf *m, struct tcphdr *th, struct socket *so,
9862     struct tcpcb *tp, struct tcpopt *to, int32_t drop_hdrlen, int32_t tlen,
9863     uint32_t tiwin, int32_t thflags, int32_t nxt_pkt, uint8_t iptos)
9864 {
9865 	int32_t ourfinisacked = 0;
9866 	int32_t ret_val;
9867 	struct tcp_bbr *bbr;
9868 
9869 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9870 	ctf_calc_rwin(so, tp);
9871 	/* Reset receive buffer auto scaling when not in bulk receive mode. */
9872 	if ((thflags & TH_RST) ||
9873 	    (tp->t_fin_is_rst && (thflags & TH_FIN)))
9874 		return (ctf_process_rst(m, th, so, tp));
9875 
9876 	/*
9877 	 * RFC5961 Section 4.2 Send challenge ACK for any SYN in
9878 	 * synchronized state.
9879 	 */
9880 	if (thflags & TH_SYN) {
9881 		ctf_challenge_ack(m, th, tp, &ret_val);
9882 		return (ret_val);
9883 	}
9884 	INP_WLOCK_ASSERT(tp->t_inpcb);
9885 	/*
9886 	 * RFC 1323 PAWS: If we have a timestamp reply on this segment and
9887 	 * it's less than ts_recent, drop it.
9888 	 */
9889 	if ((to->to_flags & TOF_TS) != 0 && tp->ts_recent &&
9890 	    TSTMP_LT(to->to_tsval, tp->ts_recent)) {
9891 		if (ctf_ts_check(m, th, tp, tlen, thflags, &ret_val))
9892 			return (ret_val);
9893 	}
9894 	INP_WLOCK_ASSERT(tp->t_inpcb);
9895 	if (ctf_drop_checks(to, m, th, tp, &tlen, &thflags, &drop_hdrlen, &ret_val)) {
9896 		return (ret_val);
9897 	}
9898 	/*
9899 	 * If new data are received on a connection after the user processes
9900 	 * are gone, then we may RST the other end depending on the outcome
9901 	 * of bbr_check_data_after_close.
9902 	 */
9903 	if ((so->so_state & SS_NOFDREF) &&
9904 	    tlen) {
9905 		/*
9906 		 * We call a new function now so we might continue and setup
9907 		 * to reset at all data being ack'd.
9908 		 */
9909 		if (bbr_check_data_after_close(m, bbr, tp, &tlen, th, so))
9910 			return (1);
9911 	}
9912 	INP_WLOCK_ASSERT(tp->t_inpcb);
9913 	/*
9914 	 * If last ACK falls within this segment's sequence numbers, record
9915 	 * its timestamp. NOTE: 1) That the test incorporates suggestions
9916 	 * from the latest proposal of the tcplw@cray.com list (Braden
9917 	 * 1993/04/26). 2) That updating only on newer timestamps interferes
9918 	 * with our earlier PAWS tests, so this check should be solely
9919 	 * predicated on the sequence space of this segment. 3) That we
9920 	 * modify the segment boundary check to be Last.ACK.Sent <= SEG.SEQ
9921 	 * + SEG.Len  instead of RFC1323's Last.ACK.Sent < SEG.SEQ +
9922 	 * SEG.Len, This modified check allows us to overcome RFC1323's
9923 	 * limitations as described in Stevens TCP/IP Illustrated Vol. 2
9924 	 * p.869. In such cases, we can still calculate the RTT correctly
9925 	 * when RCV.NXT == Last.ACK.Sent.
9926 	 */
9927 	INP_WLOCK_ASSERT(tp->t_inpcb);
9928 	if ((to->to_flags & TOF_TS) != 0 &&
9929 	    SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
9930 	    SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
9931 	    ((thflags & (TH_SYN | TH_FIN)) != 0))) {
9932 		tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
9933 		tp->ts_recent = to->to_tsval;
9934 	}
9935 	/*
9936 	 * If the ACK bit is off:  if in SYN-RECEIVED state or SENDSYN flag
9937 	 * is on (half-synchronized state), then queue data for later
9938 	 * processing; else drop segment and return.
9939 	 */
9940 	if ((thflags & TH_ACK) == 0) {
9941 		if (tp->t_flags & TF_NEEDSYN) {
9942 			return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9943 			    tiwin, thflags, nxt_pkt));
9944 		} else if (tp->t_flags & TF_ACKNOW) {
9945 			ctf_do_dropafterack(m, tp, th, thflags, tlen, &ret_val);
9946 			bbr->r_wanted_output = 1;
9947 			return (ret_val);
9948 		} else {
9949 			ctf_do_drop(m, NULL);
9950 			return (0);
9951 		}
9952 	}
9953 	/*
9954 	 * Ack processing.
9955 	 */
9956 	INP_WLOCK_ASSERT(tp->t_inpcb);
9957 	if (bbr_process_ack(m, th, so, tp, to, tiwin, tlen, &ourfinisacked, thflags, &ret_val)) {
9958 		return (ret_val);
9959 	}
9960 	if (sbavail(&so->so_snd)) {
9961 		if (ctf_progress_timeout_check(tp, true)) {
9962 			bbr_log_progress_event(bbr, tp, tick, PROGRESS_DROP, __LINE__);
9963 			ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
9964 			return (1);
9965 		}
9966 	}
9967 	INP_WLOCK_ASSERT(tp->t_inpcb);
9968 	return (bbr_process_data(m, th, so, tp, drop_hdrlen, tlen,
9969 	    tiwin, thflags, nxt_pkt));
9970 }
9971 
9972 static void
9973 bbr_stop_all_timers(struct tcpcb *tp)
9974 {
9975 	struct tcp_bbr *bbr;
9976 
9977 	/*
9978 	 * Assure no timers are running.
9979 	 */
9980 	if (tcp_timer_active(tp, TT_PERSIST)) {
9981 		/* We enter in persists, set the flag appropriately */
9982 		bbr = (struct tcp_bbr *)tp->t_fb_ptr;
9983 		bbr->rc_in_persist = 1;
9984 	}
9985 	tcp_timer_suspend(tp, TT_PERSIST);
9986 	tcp_timer_suspend(tp, TT_REXMT);
9987 	tcp_timer_suspend(tp, TT_KEEP);
9988 	tcp_timer_suspend(tp, TT_DELACK);
9989 }
9990 
9991 static void
9992 bbr_google_mode_on(struct tcp_bbr *bbr)
9993 {
9994 	bbr->rc_use_google = 1;
9995 	bbr->rc_no_pacing = 0;
9996 	bbr->r_ctl.bbr_google_discount = bbr_google_discount;
9997 	bbr->r_use_policer = bbr_policer_detection_enabled;
9998 	bbr->r_ctl.rc_probertt_int = (USECS_IN_SECOND * 10);
9999 	bbr->bbr_use_rack_cheat = 0;
10000 	bbr->r_ctl.rc_incr_tmrs = 0;
10001 	bbr->r_ctl.rc_inc_tcp_oh = 0;
10002 	bbr->r_ctl.rc_inc_ip_oh = 0;
10003 	bbr->r_ctl.rc_inc_enet_oh = 0;
10004 	reset_time(&bbr->r_ctl.rc_delrate,
10005 		   BBR_NUM_RTTS_FOR_GOOG_DEL_LIMIT);
10006 	reset_time_small(&bbr->r_ctl.rc_rttprop,
10007 			 (11 * USECS_IN_SECOND));
10008 	tcp_bbr_tso_size_check(bbr, tcp_get_usecs(&bbr->rc_tv));
10009 }
10010 
10011 static void
10012 bbr_google_mode_off(struct tcp_bbr *bbr)
10013 {
10014 	bbr->rc_use_google = 0;
10015 	bbr->r_ctl.bbr_google_discount = 0;
10016 	bbr->no_pacing_until = bbr_no_pacing_until;
10017 	bbr->r_use_policer = 0;
10018 	if (bbr->no_pacing_until)
10019 		bbr->rc_no_pacing = 1;
10020 	else
10021 		bbr->rc_no_pacing = 0;
10022 	if (bbr_use_rack_resend_cheat)
10023 		bbr->bbr_use_rack_cheat = 1;
10024 	else
10025 		bbr->bbr_use_rack_cheat = 0;
10026 	if (bbr_incr_timers)
10027 		bbr->r_ctl.rc_incr_tmrs = 1;
10028 	else
10029 		bbr->r_ctl.rc_incr_tmrs = 0;
10030 	if (bbr_include_tcp_oh)
10031 		bbr->r_ctl.rc_inc_tcp_oh = 1;
10032 	else
10033 		bbr->r_ctl.rc_inc_tcp_oh = 0;
10034 	if (bbr_include_ip_oh)
10035 		bbr->r_ctl.rc_inc_ip_oh = 1;
10036 	else
10037 		bbr->r_ctl.rc_inc_ip_oh = 0;
10038 	if (bbr_include_enet_oh)
10039 		bbr->r_ctl.rc_inc_enet_oh = 1;
10040 	else
10041 		bbr->r_ctl.rc_inc_enet_oh = 0;
10042 	bbr->r_ctl.rc_probertt_int = bbr_rtt_probe_limit;
10043 	reset_time(&bbr->r_ctl.rc_delrate,
10044 		   bbr_num_pktepo_for_del_limit);
10045 	reset_time_small(&bbr->r_ctl.rc_rttprop,
10046 			 (bbr_filter_len_sec * USECS_IN_SECOND));
10047 	tcp_bbr_tso_size_check(bbr, tcp_get_usecs(&bbr->rc_tv));
10048 }
10049 /*
10050  * Return 0 on success, non-zero on failure
10051  * which indicates the error (usually no memory).
10052  */
10053 static int
10054 bbr_init(struct tcpcb *tp)
10055 {
10056 	struct tcp_bbr *bbr = NULL;
10057 	struct inpcb *inp;
10058 	uint32_t cts;
10059 
10060 	tp->t_fb_ptr = uma_zalloc(bbr_pcb_zone, (M_NOWAIT | M_ZERO));
10061 	if (tp->t_fb_ptr == NULL) {
10062 		/*
10063 		 * We need to allocate memory but cant. The INP and INP_INFO
10064 		 * locks and they are recusive (happens during setup. So a
10065 		 * scheme to drop the locks fails :(
10066 		 *
10067 		 */
10068 		return (ENOMEM);
10069 	}
10070 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
10071 	bbr->rtt_valid = 0;
10072 	inp = tp->t_inpcb;
10073 	inp->inp_flags2 |= INP_CANNOT_DO_ECN;
10074 	inp->inp_flags2 |= INP_SUPPORTS_MBUFQ;
10075 	TAILQ_INIT(&bbr->r_ctl.rc_map);
10076 	TAILQ_INIT(&bbr->r_ctl.rc_free);
10077 	TAILQ_INIT(&bbr->r_ctl.rc_tmap);
10078 	bbr->rc_tp = tp;
10079 	if (tp->t_inpcb) {
10080 		bbr->rc_inp = tp->t_inpcb;
10081 	}
10082 	cts = tcp_get_usecs(&bbr->rc_tv);
10083 	tp->t_acktime = 0;
10084 	bbr->rc_allow_data_af_clo = bbr_ignore_data_after_close;
10085 	bbr->r_ctl.rc_reorder_fade = bbr_reorder_fade;
10086 	bbr->rc_tlp_threshold = bbr_tlp_thresh;
10087 	bbr->r_ctl.rc_reorder_shift = bbr_reorder_thresh;
10088 	bbr->r_ctl.rc_pkt_delay = bbr_pkt_delay;
10089 	bbr->r_ctl.rc_min_to = bbr_min_to;
10090 	bbr->rc_bbr_state = BBR_STATE_STARTUP;
10091 	bbr->r_ctl.bbr_lost_at_state = 0;
10092 	bbr->r_ctl.rc_lost_at_startup = 0;
10093 	bbr->rc_all_timers_stopped = 0;
10094 	bbr->r_ctl.rc_bbr_lastbtlbw = 0;
10095 	bbr->r_ctl.rc_pkt_epoch_del = 0;
10096 	bbr->r_ctl.rc_pkt_epoch = 0;
10097 	bbr->r_ctl.rc_lowest_rtt = 0xffffffff;
10098 	bbr->r_ctl.rc_bbr_hptsi_gain = bbr_high_gain;
10099 	bbr->r_ctl.rc_bbr_cwnd_gain = bbr_high_gain;
10100 	bbr->r_ctl.rc_went_idle_time = cts;
10101 	bbr->rc_pacer_started = cts;
10102 	bbr->r_ctl.rc_pkt_epoch_time = cts;
10103 	bbr->r_ctl.rc_rcvtime = cts;
10104 	bbr->r_ctl.rc_bbr_state_time = cts;
10105 	bbr->r_ctl.rc_del_time = cts;
10106 	bbr->r_ctl.rc_tlp_rxt_last_time = cts;
10107 	bbr->r_ctl.last_in_probertt = cts;
10108 	bbr->skip_gain = 0;
10109 	bbr->gain_is_limited = 0;
10110 	bbr->no_pacing_until = bbr_no_pacing_until;
10111 	if (bbr->no_pacing_until)
10112 		bbr->rc_no_pacing = 1;
10113 	if (bbr_use_google_algo) {
10114 		bbr->rc_no_pacing = 0;
10115 		bbr->rc_use_google = 1;
10116 		bbr->r_ctl.bbr_google_discount = bbr_google_discount;
10117 		bbr->r_use_policer = bbr_policer_detection_enabled;
10118 	} else {
10119 		bbr->rc_use_google = 0;
10120 		bbr->r_ctl.bbr_google_discount = 0;
10121 		bbr->r_use_policer = 0;
10122 	}
10123 	if (bbr_ts_limiting)
10124 		bbr->rc_use_ts_limit = 1;
10125 	else
10126 		bbr->rc_use_ts_limit = 0;
10127 	if (bbr_ts_can_raise)
10128 		bbr->ts_can_raise = 1;
10129 	else
10130 		bbr->ts_can_raise = 0;
10131 	if (V_tcp_delack_enabled == 1)
10132 		tp->t_delayed_ack = 2;
10133 	else if (V_tcp_delack_enabled == 0)
10134 		tp->t_delayed_ack = 0;
10135 	else if (V_tcp_delack_enabled < 100)
10136 		tp->t_delayed_ack = V_tcp_delack_enabled;
10137 	else
10138 		tp->t_delayed_ack = 2;
10139 	if (bbr->rc_use_google == 0)
10140 		bbr->r_ctl.rc_probertt_int = bbr_rtt_probe_limit;
10141 	else
10142 		bbr->r_ctl.rc_probertt_int = (USECS_IN_SECOND * 10);
10143 	bbr->r_ctl.rc_min_rto_ms = bbr_rto_min_ms;
10144 	bbr->rc_max_rto_sec = bbr_rto_max_sec;
10145 	bbr->rc_init_win = bbr_def_init_win;
10146 	if (tp->t_flags & TF_REQ_TSTMP)
10147 		bbr->rc_last_options = TCP_TS_OVERHEAD;
10148 	bbr->r_ctl.rc_pace_max_segs = tp->t_maxseg - bbr->rc_last_options;
10149 	bbr->r_ctl.rc_high_rwnd = tp->snd_wnd;
10150 	bbr->r_init_rtt = 1;
10151 
10152 	counter_u64_add(bbr_flows_nohdwr_pacing, 1);
10153 	if (bbr_allow_hdwr_pacing)
10154 		bbr->bbr_hdw_pace_ena = 1;
10155 	else
10156 		bbr->bbr_hdw_pace_ena = 0;
10157 	if (bbr_sends_full_iwnd)
10158 		bbr->bbr_init_win_cheat = 1;
10159 	else
10160 		bbr->bbr_init_win_cheat = 0;
10161 	bbr->r_ctl.bbr_utter_max = bbr_hptsi_utter_max;
10162 	bbr->r_ctl.rc_drain_pg = bbr_drain_gain;
10163 	bbr->r_ctl.rc_startup_pg = bbr_high_gain;
10164 	bbr->rc_loss_exit = bbr_exit_startup_at_loss;
10165 	bbr->r_ctl.bbr_rttprobe_gain_val = bbr_rttprobe_gain;
10166 	bbr->r_ctl.bbr_hptsi_per_second = bbr_hptsi_per_second;
10167 	bbr->r_ctl.bbr_hptsi_segments_delay_tar = bbr_hptsi_segments_delay_tar;
10168 	bbr->r_ctl.bbr_hptsi_segments_max = bbr_hptsi_segments_max;
10169 	bbr->r_ctl.bbr_hptsi_segments_floor = bbr_hptsi_segments_floor;
10170 	bbr->r_ctl.bbr_hptsi_bytes_min = bbr_hptsi_bytes_min;
10171 	bbr->r_ctl.bbr_cross_over = bbr_cross_over;
10172 	bbr->r_ctl.rc_rtt_shrinks = cts;
10173 	if (bbr->rc_use_google) {
10174 		setup_time_filter(&bbr->r_ctl.rc_delrate,
10175 				  FILTER_TYPE_MAX,
10176 				  BBR_NUM_RTTS_FOR_GOOG_DEL_LIMIT);
10177 		setup_time_filter_small(&bbr->r_ctl.rc_rttprop,
10178 					FILTER_TYPE_MIN, (11 * USECS_IN_SECOND));
10179 	} else {
10180 		setup_time_filter(&bbr->r_ctl.rc_delrate,
10181 				  FILTER_TYPE_MAX,
10182 				  bbr_num_pktepo_for_del_limit);
10183 		setup_time_filter_small(&bbr->r_ctl.rc_rttprop,
10184 					FILTER_TYPE_MIN, (bbr_filter_len_sec * USECS_IN_SECOND));
10185 	}
10186 	bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_INIT, 0);
10187 	if (bbr_uses_idle_restart)
10188 		bbr->rc_use_idle_restart = 1;
10189 	else
10190 		bbr->rc_use_idle_restart = 0;
10191 	bbr->r_ctl.rc_bbr_cur_del_rate = 0;
10192 	bbr->r_ctl.rc_initial_hptsi_bw = bbr_initial_bw_bps;
10193 	if (bbr_resends_use_tso)
10194 		bbr->rc_resends_use_tso = 1;
10195 #ifdef NETFLIX_PEAKRATE
10196 	tp->t_peakrate_thr = tp->t_maxpeakrate;
10197 #endif
10198 	if (tp->snd_una != tp->snd_max) {
10199 		/* Create a send map for the current outstanding data */
10200 		struct bbr_sendmap *rsm;
10201 
10202 		rsm = bbr_alloc(bbr);
10203 		if (rsm == NULL) {
10204 			uma_zfree(bbr_pcb_zone, tp->t_fb_ptr);
10205 			tp->t_fb_ptr = NULL;
10206 			return (ENOMEM);
10207 		}
10208 		rsm->r_flags = BBR_OVERMAX;
10209 		rsm->r_tim_lastsent[0] = cts;
10210 		rsm->r_rtr_cnt = 1;
10211 		rsm->r_rtr_bytes = 0;
10212 		rsm->r_start = tp->snd_una;
10213 		rsm->r_end = tp->snd_max;
10214 		rsm->r_dupack = 0;
10215 		rsm->r_delivered = bbr->r_ctl.rc_delivered;
10216 		rsm->r_ts_valid = 0;
10217 		rsm->r_del_ack_ts = tp->ts_recent;
10218 		rsm->r_del_time = cts;
10219 		if (bbr->r_ctl.r_app_limited_until)
10220 			rsm->r_app_limited = 1;
10221 		else
10222 			rsm->r_app_limited = 0;
10223 		TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_map, rsm, r_next);
10224 		TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_tmap, rsm, r_tnext);
10225 		rsm->r_in_tmap = 1;
10226 		if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW)
10227 			rsm->r_bbr_state = bbr_state_val(bbr);
10228 		else
10229 			rsm->r_bbr_state = 8;
10230 	}
10231 	if (bbr_use_rack_resend_cheat && (bbr->rc_use_google == 0))
10232 		bbr->bbr_use_rack_cheat = 1;
10233 	if (bbr_incr_timers && (bbr->rc_use_google == 0))
10234 		bbr->r_ctl.rc_incr_tmrs = 1;
10235 	if (bbr_include_tcp_oh && (bbr->rc_use_google == 0))
10236 		bbr->r_ctl.rc_inc_tcp_oh = 1;
10237 	if (bbr_include_ip_oh && (bbr->rc_use_google == 0))
10238 		bbr->r_ctl.rc_inc_ip_oh = 1;
10239 	if (bbr_include_enet_oh && (bbr->rc_use_google == 0))
10240 		bbr->r_ctl.rc_inc_enet_oh = 1;
10241 
10242 	bbr_log_type_statechange(bbr, cts, __LINE__);
10243 	if (TCPS_HAVEESTABLISHED(tp->t_state) &&
10244 	    (tp->t_srtt)) {
10245 		uint32_t rtt;
10246 
10247 		rtt = (TICKS_2_USEC(tp->t_srtt) >> TCP_RTT_SHIFT);
10248 		apply_filter_min_small(&bbr->r_ctl.rc_rttprop, rtt, cts);
10249 	}
10250 	/* announce the settings and state */
10251 	bbr_log_settings_change(bbr, BBR_RECOVERY_LOWRTT);
10252 	tcp_bbr_tso_size_check(bbr, cts);
10253 	/*
10254 	 * Now call the generic function to start a timer. This will place
10255 	 * the TCB on the hptsi wheel if a timer is needed with appropriate
10256 	 * flags.
10257 	 */
10258 	bbr_stop_all_timers(tp);
10259 	bbr_start_hpts_timer(bbr, tp, cts, 5, 0, 0);
10260 	return (0);
10261 }
10262 
10263 /*
10264  * Return 0 if we can accept the connection. Return
10265  * non-zero if we can't handle the connection. A EAGAIN
10266  * means you need to wait until the connection is up.
10267  * a EADDRNOTAVAIL means we can never handle the connection
10268  * (no SACK).
10269  */
10270 static int
10271 bbr_handoff_ok(struct tcpcb *tp)
10272 {
10273 	if ((tp->t_state == TCPS_CLOSED) ||
10274 	    (tp->t_state == TCPS_LISTEN)) {
10275 		/* Sure no problem though it may not stick */
10276 		return (0);
10277 	}
10278 	if ((tp->t_state == TCPS_SYN_SENT) ||
10279 	    (tp->t_state == TCPS_SYN_RECEIVED)) {
10280 		/*
10281 		 * We really don't know you have to get to ESTAB or beyond
10282 		 * to tell.
10283 		 */
10284 		return (EAGAIN);
10285 	}
10286 	if (tp->t_flags & TF_SENTFIN)
10287 		return (EINVAL);
10288 	if ((tp->t_flags & TF_SACK_PERMIT) || bbr_sack_not_required) {
10289 		return (0);
10290 	}
10291 	/*
10292 	 * If we reach here we don't do SACK on this connection so we can
10293 	 * never do rack.
10294 	 */
10295 	return (EINVAL);
10296 }
10297 
10298 static void
10299 bbr_fini(struct tcpcb *tp, int32_t tcb_is_purged)
10300 {
10301 	if (tp->t_fb_ptr) {
10302 		uint32_t calc;
10303 		struct tcp_bbr *bbr;
10304 		struct bbr_sendmap *rsm;
10305 
10306 		bbr = (struct tcp_bbr *)tp->t_fb_ptr;
10307 		if (bbr->r_ctl.crte)
10308 			tcp_rel_pacing_rate(bbr->r_ctl.crte, bbr->rc_tp);
10309 		bbr_log_flowend(bbr);
10310 		bbr->rc_tp = NULL;
10311 		if (tp->t_inpcb) {
10312 			/* Backout any flags2 we applied */
10313 			tp->t_inpcb->inp_flags2 &= ~INP_CANNOT_DO_ECN;
10314 			tp->t_inpcb->inp_flags2 &= ~INP_SUPPORTS_MBUFQ;
10315 			tp->t_inpcb->inp_flags2 &= ~INP_MBUF_QUEUE_READY;
10316 		}
10317 		if (bbr->bbr_hdrw_pacing)
10318 			counter_u64_add(bbr_flows_whdwr_pacing, -1);
10319 		else
10320 			counter_u64_add(bbr_flows_nohdwr_pacing, -1);
10321 		rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
10322 		while (rsm) {
10323 			TAILQ_REMOVE(&bbr->r_ctl.rc_map, rsm, r_next);
10324 			uma_zfree(bbr_zone, rsm);
10325 			rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
10326 		}
10327 		rsm = TAILQ_FIRST(&bbr->r_ctl.rc_free);
10328 		while (rsm) {
10329 			TAILQ_REMOVE(&bbr->r_ctl.rc_free, rsm, r_next);
10330 			uma_zfree(bbr_zone, rsm);
10331 			rsm = TAILQ_FIRST(&bbr->r_ctl.rc_free);
10332 		}
10333 		calc = bbr->r_ctl.rc_high_rwnd - bbr->r_ctl.rc_init_rwnd;
10334 		if (calc > (bbr->r_ctl.rc_init_rwnd / 10))
10335 			BBR_STAT_INC(bbr_dynamic_rwnd);
10336 		else
10337 			BBR_STAT_INC(bbr_static_rwnd);
10338 		bbr->r_ctl.rc_free_cnt = 0;
10339 		uma_zfree(bbr_pcb_zone, tp->t_fb_ptr);
10340 		tp->t_fb_ptr = NULL;
10341 	}
10342 	/* Make sure snd_nxt is correctly set */
10343 	tp->snd_nxt = tp->snd_max;
10344 }
10345 
10346 static void
10347 bbr_set_state(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t win)
10348 {
10349 	switch (tp->t_state) {
10350 	case TCPS_SYN_SENT:
10351 		bbr->r_state = TCPS_SYN_SENT;
10352 		bbr->r_substate = bbr_do_syn_sent;
10353 		break;
10354 	case TCPS_SYN_RECEIVED:
10355 		bbr->r_state = TCPS_SYN_RECEIVED;
10356 		bbr->r_substate = bbr_do_syn_recv;
10357 		break;
10358 	case TCPS_ESTABLISHED:
10359 		bbr->r_ctl.rc_init_rwnd = max(win, bbr->rc_tp->snd_wnd);
10360 		bbr->r_state = TCPS_ESTABLISHED;
10361 		bbr->r_substate = bbr_do_established;
10362 		break;
10363 	case TCPS_CLOSE_WAIT:
10364 		bbr->r_state = TCPS_CLOSE_WAIT;
10365 		bbr->r_substate = bbr_do_close_wait;
10366 		break;
10367 	case TCPS_FIN_WAIT_1:
10368 		bbr->r_state = TCPS_FIN_WAIT_1;
10369 		bbr->r_substate = bbr_do_fin_wait_1;
10370 		break;
10371 	case TCPS_CLOSING:
10372 		bbr->r_state = TCPS_CLOSING;
10373 		bbr->r_substate = bbr_do_closing;
10374 		break;
10375 	case TCPS_LAST_ACK:
10376 		bbr->r_state = TCPS_LAST_ACK;
10377 		bbr->r_substate = bbr_do_lastack;
10378 		break;
10379 	case TCPS_FIN_WAIT_2:
10380 		bbr->r_state = TCPS_FIN_WAIT_2;
10381 		bbr->r_substate = bbr_do_fin_wait_2;
10382 		break;
10383 	case TCPS_LISTEN:
10384 	case TCPS_CLOSED:
10385 	case TCPS_TIME_WAIT:
10386 	default:
10387 		break;
10388 	};
10389 }
10390 
10391 static void
10392 bbr_substate_change(struct tcp_bbr *bbr, uint32_t cts, int32_t line, int dolog)
10393 {
10394 	/*
10395 	 * Now what state are we going into now? Is there adjustments
10396 	 * needed?
10397 	 */
10398 	int32_t old_state, old_gain;
10399 
10400 	old_state = bbr_state_val(bbr);
10401 	old_gain = bbr->r_ctl.rc_bbr_hptsi_gain;
10402 	if (bbr_state_val(bbr) == BBR_SUB_LEVEL1) {
10403 		/* Save the lowest srtt we saw in our end of the sub-state */
10404 		bbr->rc_hit_state_1 = 0;
10405 		if (bbr->r_ctl.bbr_smallest_srtt_this_state != 0xffffffff)
10406 			bbr->r_ctl.bbr_smallest_srtt_state2 = bbr->r_ctl.bbr_smallest_srtt_this_state;
10407 	}
10408 	bbr->rc_bbr_substate++;
10409 	if (bbr->rc_bbr_substate >= BBR_SUBSTATE_COUNT) {
10410 		/* Cycle back to first state-> gain */
10411 		bbr->rc_bbr_substate = 0;
10412 	}
10413 	if (bbr_state_val(bbr) == BBR_SUB_GAIN) {
10414 		/*
10415 		 * We enter the gain(5/4) cycle (possibly less if
10416 		 * shallow buffer detection is enabled)
10417 		 */
10418 		if (bbr->skip_gain) {
10419 			/*
10420 			 * Hardware pacing has set our rate to
10421 			 * the max and limited our b/w just
10422 			 * do level i.e. no gain.
10423 			 */
10424 			bbr->r_ctl.rc_bbr_hptsi_gain = bbr_hptsi_gain[BBR_SUB_LEVEL1];
10425 		} else if (bbr->gain_is_limited &&
10426 			   bbr->bbr_hdrw_pacing &&
10427 			   bbr->r_ctl.crte) {
10428 			/*
10429 			 * We can't gain above the hardware pacing
10430 			 * rate which is less than our rate + the gain
10431 			 * calculate the gain needed to reach the hardware
10432 			 * pacing rate..
10433 			 */
10434 			uint64_t bw, rate, gain_calc;
10435 
10436 			bw = bbr_get_bw(bbr);
10437 			rate = bbr->r_ctl.crte->rate;
10438 			if ((rate > bw) &&
10439 			    (((bw *  (uint64_t)bbr_hptsi_gain[BBR_SUB_GAIN]) / (uint64_t)BBR_UNIT) > rate)) {
10440 				gain_calc = (rate * BBR_UNIT) / bw;
10441 				if (gain_calc < BBR_UNIT)
10442 					gain_calc = BBR_UNIT;
10443 				bbr->r_ctl.rc_bbr_hptsi_gain = (uint16_t)gain_calc;
10444 			} else {
10445 				bbr->r_ctl.rc_bbr_hptsi_gain = bbr_hptsi_gain[BBR_SUB_GAIN];
10446 			}
10447 		} else
10448 			bbr->r_ctl.rc_bbr_hptsi_gain = bbr_hptsi_gain[BBR_SUB_GAIN];
10449 		if ((bbr->rc_use_google == 0) && (bbr_gain_to_target == 0)) {
10450 			bbr->r_ctl.rc_bbr_state_atflight = cts;
10451 		} else
10452 			bbr->r_ctl.rc_bbr_state_atflight = 0;
10453 	} else if (bbr_state_val(bbr) == BBR_SUB_DRAIN) {
10454 		bbr->rc_hit_state_1 = 1;
10455 		bbr->r_ctl.rc_exta_time_gd = 0;
10456 		bbr->r_ctl.flightsize_at_drain = ctf_flight_size(bbr->rc_tp,
10457 						     (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
10458 		if (bbr_state_drain_2_tar) {
10459 			bbr->r_ctl.rc_bbr_state_atflight = 0;
10460 		} else
10461 			bbr->r_ctl.rc_bbr_state_atflight = cts;
10462 		bbr->r_ctl.rc_bbr_hptsi_gain = bbr_hptsi_gain[BBR_SUB_DRAIN];
10463 	} else {
10464 		/* All other cycles hit here 2-7 */
10465 		if ((old_state == BBR_SUB_DRAIN) && bbr->rc_hit_state_1) {
10466 			if (bbr_sub_drain_slam_cwnd &&
10467 			    (bbr->rc_use_google == 0) &&
10468 			    (bbr->rc_tp->snd_cwnd < bbr->r_ctl.rc_saved_cwnd)) {
10469 				bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_saved_cwnd;
10470 				bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10471 			}
10472 			if ((cts - bbr->r_ctl.rc_bbr_state_time) > bbr_get_rtt(bbr, BBR_RTT_PROP))
10473 				bbr->r_ctl.rc_exta_time_gd += ((cts - bbr->r_ctl.rc_bbr_state_time) -
10474 							       bbr_get_rtt(bbr, BBR_RTT_PROP));
10475 			else
10476 				bbr->r_ctl.rc_exta_time_gd = 0;
10477 			if (bbr->r_ctl.rc_exta_time_gd) {
10478 				bbr->r_ctl.rc_level_state_extra = bbr->r_ctl.rc_exta_time_gd;
10479 				/* Now chop up the time for each state (div by 7) */
10480 				bbr->r_ctl.rc_level_state_extra /= 7;
10481 				if (bbr_rand_ot && bbr->r_ctl.rc_level_state_extra) {
10482 					/* Add a randomization */
10483 					bbr_randomize_extra_state_time(bbr);
10484 				}
10485 			}
10486 		}
10487 		bbr->r_ctl.rc_bbr_state_atflight = max(1, cts);
10488 		bbr->r_ctl.rc_bbr_hptsi_gain = bbr_hptsi_gain[bbr_state_val(bbr)];
10489 	}
10490 	if (bbr->rc_use_google) {
10491 		bbr->r_ctl.rc_bbr_state_atflight = max(1, cts);
10492 	}
10493 	bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
10494 	bbr->r_ctl.rc_bbr_cwnd_gain = bbr_cwnd_gain;
10495 	if (dolog)
10496 		bbr_log_type_statechange(bbr, cts, line);
10497 
10498 	if (SEQ_GT(cts, bbr->r_ctl.rc_bbr_state_time)) {
10499 		uint32_t time_in;
10500 
10501 		time_in = cts - bbr->r_ctl.rc_bbr_state_time;
10502 		if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW) {
10503 			counter_u64_add(bbr_state_time[(old_state + 5)], time_in);
10504 		} else {
10505 			counter_u64_add(bbr_state_time[bbr->rc_bbr_state], time_in);
10506 		}
10507 	}
10508 	bbr->r_ctl.bbr_smallest_srtt_this_state = 0xffffffff;
10509 	bbr_set_state_target(bbr, __LINE__);
10510 	if (bbr_sub_drain_slam_cwnd &&
10511 	    (bbr->rc_use_google == 0) &&
10512 	    (bbr_state_val(bbr) == BBR_SUB_DRAIN)) {
10513 		/* Slam down the cwnd */
10514 		bbr->r_ctl.rc_saved_cwnd = bbr->rc_tp->snd_cwnd;
10515 		bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_target_at_state;
10516 		if (bbr_sub_drain_app_limit) {
10517 			/* Go app limited if we are on a long drain */
10518 			bbr->r_ctl.r_app_limited_until = (bbr->r_ctl.rc_delivered +
10519 							  ctf_flight_size(bbr->rc_tp,
10520 							      (bbr->r_ctl.rc_sacked +
10521 							       bbr->r_ctl.rc_lost_bytes)));
10522 		}
10523 		bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10524 	}
10525 	if (bbr->rc_lt_use_bw) {
10526 		/* In policed mode we clamp pacing_gain to BBR_UNIT */
10527 		bbr->r_ctl.rc_bbr_hptsi_gain = BBR_UNIT;
10528 	}
10529 	/* Google changes TSO size every cycle */
10530 	if (bbr->rc_use_google)
10531 		tcp_bbr_tso_size_check(bbr, cts);
10532 	bbr->r_ctl.gain_epoch = cts;
10533 	bbr->r_ctl.rc_bbr_state_time = cts;
10534 	bbr->r_ctl.substate_pe = bbr->r_ctl.rc_pkt_epoch;
10535 }
10536 
10537 static void
10538 bbr_set_probebw_google_gains(struct tcp_bbr *bbr, uint32_t cts, uint32_t losses)
10539 {
10540 	if ((bbr_state_val(bbr) == BBR_SUB_DRAIN) &&
10541 	    (google_allow_early_out == 1) &&
10542 	    (bbr->r_ctl.rc_flight_at_input <= bbr->r_ctl.rc_target_at_state)) {
10543 		/* We have reached out target flight size possibly early */
10544 		goto change_state;
10545 	}
10546 	if (TSTMP_LT(cts, bbr->r_ctl.rc_bbr_state_time)) {
10547 		return;
10548 	}
10549 	if ((cts - bbr->r_ctl.rc_bbr_state_time) < bbr_get_rtt(bbr, BBR_RTT_PROP)) {
10550 		/*
10551 		 * Must be a rttProp movement forward before
10552 		 * we can change states.
10553 		 */
10554 		return;
10555 	}
10556 	if (bbr_state_val(bbr) == BBR_SUB_GAIN) {
10557 		/*
10558 		 * The needed time has passed but for
10559 		 * the gain cycle extra rules apply:
10560 		 * 1) If we have seen loss, we exit
10561 		 * 2) If we have not reached the target
10562 		 *    we stay in GAIN (gain-to-target).
10563 		 */
10564 		if (google_consider_lost && losses)
10565 			goto change_state;
10566 		if (bbr->r_ctl.rc_target_at_state > bbr->r_ctl.rc_flight_at_input) {
10567 			return;
10568 		}
10569 	}
10570 change_state:
10571 	/* For gain we must reach our target, all others last 1 rttProp */
10572 	bbr_substate_change(bbr, cts, __LINE__, 1);
10573 }
10574 
10575 static void
10576 bbr_set_probebw_gains(struct tcp_bbr *bbr, uint32_t cts, uint32_t losses)
10577 {
10578 	uint32_t flight, bbr_cur_cycle_time;
10579 
10580 	if (bbr->rc_use_google) {
10581 		bbr_set_probebw_google_gains(bbr, cts, losses);
10582 		return;
10583 	}
10584 	if (cts == 0) {
10585 		/*
10586 		 * Never alow cts to be 0 we
10587 		 * do this so we can judge if
10588 		 * we have set a timestamp.
10589 		 */
10590 		cts = 1;
10591 	}
10592 	if (bbr_state_is_pkt_epoch)
10593 		bbr_cur_cycle_time = bbr_get_rtt(bbr, BBR_RTT_PKTRTT);
10594 	else
10595 		bbr_cur_cycle_time = bbr_get_rtt(bbr, BBR_RTT_PROP);
10596 
10597 	if (bbr->r_ctl.rc_bbr_state_atflight == 0) {
10598 		if (bbr_state_val(bbr) == BBR_SUB_DRAIN) {
10599 			flight = ctf_flight_size(bbr->rc_tp,
10600 				     (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
10601 			if (bbr_sub_drain_slam_cwnd && bbr->rc_hit_state_1) {
10602 				/* Keep it slam down */
10603 				if (bbr->rc_tp->snd_cwnd > bbr->r_ctl.rc_target_at_state) {
10604 					bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_target_at_state;
10605 					bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10606 				}
10607 				if (bbr_sub_drain_app_limit) {
10608 					/* Go app limited if we are on a long drain */
10609 					bbr->r_ctl.r_app_limited_until = (bbr->r_ctl.rc_delivered + flight);
10610 				}
10611 			}
10612 			if (TSTMP_GT(cts, bbr->r_ctl.gain_epoch) &&
10613 			    (((cts - bbr->r_ctl.gain_epoch) > bbr_get_rtt(bbr, BBR_RTT_PROP)) ||
10614 			     (flight >= bbr->r_ctl.flightsize_at_drain))) {
10615 				/*
10616 				 * Still here after the same time as
10617 				 * the gain. We need to drain harder
10618 				 * for the next srtt. Reduce by a set amount
10619 				 * the gain drop is capped at DRAIN states
10620 				 * value (88).
10621 				 */
10622 				bbr->r_ctl.flightsize_at_drain = flight;
10623 				if (bbr_drain_drop_mul &&
10624 				    bbr_drain_drop_div &&
10625 				    (bbr_drain_drop_mul < bbr_drain_drop_div)) {
10626 					/* Use your specific drop value (def 4/5 = 20%) */
10627 					bbr->r_ctl.rc_bbr_hptsi_gain *= bbr_drain_drop_mul;
10628 					bbr->r_ctl.rc_bbr_hptsi_gain /= bbr_drain_drop_div;
10629 				} else {
10630 					/* You get drop of 20% */
10631 					bbr->r_ctl.rc_bbr_hptsi_gain *= 4;
10632 					bbr->r_ctl.rc_bbr_hptsi_gain /= 5;
10633 				}
10634 				if (bbr->r_ctl.rc_bbr_hptsi_gain <= bbr_drain_floor) {
10635 					/* Reduce our gain again to the bottom  */
10636 					bbr->r_ctl.rc_bbr_hptsi_gain = max(bbr_drain_floor, 1);
10637 				}
10638 				bbr_log_exit_gain(bbr, cts, 4);
10639 				/*
10640 				 * Extend out so we wait another
10641 				 * epoch before dropping again.
10642 				 */
10643 				bbr->r_ctl.gain_epoch = cts;
10644 			}
10645 			if (flight <= bbr->r_ctl.rc_target_at_state) {
10646 				if (bbr_sub_drain_slam_cwnd &&
10647 				    (bbr->rc_use_google == 0) &&
10648 				    (bbr->rc_tp->snd_cwnd < bbr->r_ctl.rc_saved_cwnd)) {
10649 					bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_saved_cwnd;
10650 					bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10651 				}
10652 				bbr->r_ctl.rc_bbr_state_atflight = max(cts, 1);
10653 				bbr_log_exit_gain(bbr, cts, 3);
10654 			}
10655 		} else {
10656 			/* Its a gain  */
10657 			if (bbr->r_ctl.rc_lost > bbr->r_ctl.bbr_lost_at_state) {
10658 				bbr->r_ctl.rc_bbr_state_atflight = max(cts, 1);
10659 				goto change_state;
10660 			}
10661 			if ((ctf_outstanding(bbr->rc_tp) >= bbr->r_ctl.rc_target_at_state) ||
10662 			    ((ctf_outstanding(bbr->rc_tp) +  bbr->rc_tp->t_maxseg - 1) >=
10663 			     bbr->rc_tp->snd_wnd)) {
10664 				bbr->r_ctl.rc_bbr_state_atflight = max(cts, 1);
10665 				bbr_log_exit_gain(bbr, cts, 2);
10666 			}
10667 		}
10668 		/**
10669 		 * We fall through and return always one of two things has
10670 		 * occured.
10671 		 * 1) We are still not at target
10672 		 *    <or>
10673 		 * 2) We reached the target and set rc_bbr_state_atflight
10674 		 *    which means we no longer hit this block
10675 		 *    next time we are called.
10676 		 */
10677 		return;
10678 	}
10679 change_state:
10680 	if (TSTMP_LT(cts, bbr->r_ctl.rc_bbr_state_time))
10681 		return;
10682 	if ((cts - bbr->r_ctl.rc_bbr_state_time) < bbr_cur_cycle_time) {
10683 		/* Less than a full time-period has passed */
10684 		return;
10685 	}
10686 	if (bbr->r_ctl.rc_level_state_extra &&
10687 	    (bbr_state_val(bbr) > BBR_SUB_DRAIN) &&
10688 	    ((cts - bbr->r_ctl.rc_bbr_state_time) <
10689 	     (bbr_cur_cycle_time + bbr->r_ctl.rc_level_state_extra))) {
10690 		/* Less than a full time-period + extra has passed */
10691 		return;
10692 	}
10693 	if (bbr_gain_gets_extra_too &&
10694 	    bbr->r_ctl.rc_level_state_extra &&
10695 	    (bbr_state_val(bbr) == BBR_SUB_GAIN) &&
10696 	    ((cts - bbr->r_ctl.rc_bbr_state_time) <
10697 	     (bbr_cur_cycle_time + bbr->r_ctl.rc_level_state_extra))) {
10698 		/* Less than a full time-period + extra has passed */
10699 		return;
10700 	}
10701 	bbr_substate_change(bbr, cts, __LINE__, 1);
10702 }
10703 
10704 static uint32_t
10705 bbr_get_a_state_target(struct tcp_bbr *bbr, uint32_t gain)
10706 {
10707 	uint32_t mss, tar;
10708 
10709 	if (bbr->rc_use_google) {
10710 		/* Google just uses the cwnd target */
10711 		tar = bbr_get_target_cwnd(bbr, bbr_get_bw(bbr), gain);
10712 	} else {
10713 		mss = min((bbr->rc_tp->t_maxseg - bbr->rc_last_options),
10714 			  bbr->r_ctl.rc_pace_max_segs);
10715 		/* Get the base cwnd with gain rounded to a mss */
10716 		tar = roundup(bbr_get_raw_target_cwnd(bbr, bbr_get_bw(bbr),
10717 						      gain), mss);
10718 		/* Make sure it is within our min */
10719 		if (tar < get_min_cwnd(bbr))
10720 			return (get_min_cwnd(bbr));
10721 	}
10722 	return (tar);
10723 }
10724 
10725 static void
10726 bbr_set_state_target(struct tcp_bbr *bbr, int line)
10727 {
10728 	uint32_t tar, meth;
10729 
10730 	if ((bbr->rc_bbr_state == BBR_STATE_PROBE_RTT) &&
10731 	    ((bbr->r_ctl.bbr_rttprobe_gain_val == 0) || bbr->rc_use_google)) {
10732 		/* Special case using old probe-rtt method */
10733 		tar = bbr_rtt_probe_cwndtarg * (bbr->rc_tp->t_maxseg - bbr->rc_last_options);
10734 		meth = 1;
10735 	} else {
10736 		/* Non-probe-rtt case and reduced probe-rtt  */
10737 		if ((bbr->rc_bbr_state == BBR_STATE_PROBE_BW) &&
10738 		    (bbr->r_ctl.rc_bbr_hptsi_gain > BBR_UNIT)) {
10739 			/* For gain cycle we use the hptsi gain */
10740 			tar = bbr_get_a_state_target(bbr, bbr->r_ctl.rc_bbr_hptsi_gain);
10741 			meth = 2;
10742 		} else if ((bbr_target_is_bbunit) || bbr->rc_use_google) {
10743 			/*
10744 			 * If configured, or for google all other states
10745 			 * get BBR_UNIT.
10746 			 */
10747 			tar = bbr_get_a_state_target(bbr, BBR_UNIT);
10748 			meth = 3;
10749 		} else {
10750 			/*
10751 			 * Or we set a target based on the pacing gain
10752 			 * for non-google mode and default (non-configured).
10753 			 * Note we don't set a target goal below drain (192).
10754 			 */
10755 			if (bbr->r_ctl.rc_bbr_hptsi_gain < bbr_hptsi_gain[BBR_SUB_DRAIN])  {
10756 				tar = bbr_get_a_state_target(bbr, bbr_hptsi_gain[BBR_SUB_DRAIN]);
10757 				meth = 4;
10758 			} else {
10759 				tar = bbr_get_a_state_target(bbr, bbr->r_ctl.rc_bbr_hptsi_gain);
10760 				meth = 5;
10761 			}
10762 		}
10763 	}
10764 	bbr_log_set_of_state_target(bbr, tar, line, meth);
10765 	bbr->r_ctl.rc_target_at_state = tar;
10766 }
10767 
10768 static void
10769 bbr_enter_probe_rtt(struct tcp_bbr *bbr, uint32_t cts, int32_t line)
10770 {
10771 	/* Change to probe_rtt */
10772 	uint32_t time_in;
10773 
10774 	bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
10775 	bbr->r_ctl.flightsize_at_drain = ctf_flight_size(bbr->rc_tp,
10776 					     (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
10777 	bbr->r_ctl.r_app_limited_until = (bbr->r_ctl.flightsize_at_drain
10778 					  + bbr->r_ctl.rc_delivered);
10779 	/* Setup so we force feed the filter */
10780 	if (bbr->rc_use_google || bbr_probertt_sets_rtt)
10781 		bbr->rc_prtt_set_ts = 1;
10782 	if (SEQ_GT(cts, bbr->r_ctl.rc_bbr_state_time)) {
10783 		time_in = cts - bbr->r_ctl.rc_bbr_state_time;
10784 		counter_u64_add(bbr_state_time[bbr->rc_bbr_state], time_in);
10785 	}
10786 	bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_ENTERPROBE, 0);
10787 	bbr->r_ctl.rc_rtt_shrinks = cts;
10788 	bbr->r_ctl.last_in_probertt = cts;
10789 	bbr->r_ctl.rc_probertt_srttchktim = cts;
10790 	bbr->r_ctl.rc_bbr_state_time = cts;
10791 	bbr->rc_bbr_state = BBR_STATE_PROBE_RTT;
10792 	/* We need to force the filter to update */
10793 
10794 	if ((bbr_sub_drain_slam_cwnd) &&
10795 	    bbr->rc_hit_state_1 &&
10796 	    (bbr->rc_use_google == 0) &&
10797 	    (bbr_state_val(bbr) == BBR_SUB_DRAIN)) {
10798 		if (bbr->rc_tp->snd_cwnd > bbr->r_ctl.rc_saved_cwnd)
10799 			bbr->r_ctl.rc_saved_cwnd = bbr->rc_tp->snd_cwnd;
10800 	} else
10801 		bbr->r_ctl.rc_saved_cwnd = bbr->rc_tp->snd_cwnd;
10802 	/* Update the lost */
10803 	bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
10804 	if ((bbr->r_ctl.bbr_rttprobe_gain_val == 0) || bbr->rc_use_google){
10805 		/* Set to the non-configurable default of 4 (PROBE_RTT_MIN)  */
10806 		bbr->rc_tp->snd_cwnd = bbr_rtt_probe_cwndtarg * (bbr->rc_tp->t_maxseg - bbr->rc_last_options);
10807 		bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10808 		bbr->r_ctl.rc_bbr_hptsi_gain = BBR_UNIT;
10809 		bbr->r_ctl.rc_bbr_cwnd_gain = BBR_UNIT;
10810 		bbr_log_set_of_state_target(bbr, bbr->rc_tp->snd_cwnd, __LINE__, 6);
10811 		bbr->r_ctl.rc_target_at_state = bbr->rc_tp->snd_cwnd;
10812 	} else {
10813 		/*
10814 		 * We bring it down slowly by using a hptsi gain that is
10815 		 * probably 75%. This will slowly float down our outstanding
10816 		 * without tampering with the cwnd.
10817 		 */
10818 		bbr->r_ctl.rc_bbr_hptsi_gain = bbr->r_ctl.bbr_rttprobe_gain_val;
10819 		bbr->r_ctl.rc_bbr_cwnd_gain = BBR_UNIT;
10820 		bbr_set_state_target(bbr, __LINE__);
10821 		if (bbr_prtt_slam_cwnd &&
10822 		    (bbr->rc_tp->snd_cwnd > bbr->r_ctl.rc_target_at_state)) {
10823 			bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_target_at_state;
10824 			bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10825 		}
10826 	}
10827 	if (ctf_flight_size(bbr->rc_tp,
10828 		(bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes)) <=
10829 	    bbr->r_ctl.rc_target_at_state) {
10830 		/* We are at target */
10831 		bbr->r_ctl.rc_bbr_enters_probertt = cts;
10832 	} else {
10833 		/* We need to come down to reach target before our time begins */
10834 		bbr->r_ctl.rc_bbr_enters_probertt = 0;
10835 	}
10836 	bbr->r_ctl.rc_pe_of_prtt = bbr->r_ctl.rc_pkt_epoch;
10837 	BBR_STAT_INC(bbr_enter_probertt);
10838 	bbr_log_exit_gain(bbr, cts, 0);
10839 	bbr_log_type_statechange(bbr, cts, line);
10840 }
10841 
10842 static void
10843 bbr_check_probe_rtt_limits(struct tcp_bbr *bbr, uint32_t cts)
10844 {
10845 	/*
10846 	 * Sanity check on probe-rtt intervals.
10847 	 * In crazy situations where we are competing
10848 	 * against new-reno flows with huge buffers
10849 	 * our rtt-prop interval could come to dominate
10850 	 * things if we can't get through a full set
10851 	 * of cycles, we need to adjust it.
10852 	 */
10853 	if (bbr_can_adjust_probertt &&
10854 	    (bbr->rc_use_google == 0)) {
10855 		uint16_t val = 0;
10856 		uint32_t cur_rttp, fval, newval, baseval;
10857 
10858 		/* Are we to small and go into probe-rtt to often? */
10859 		baseval = (bbr_get_rtt(bbr, BBR_RTT_PROP) * (BBR_SUBSTATE_COUNT + 1));
10860 		cur_rttp = roundup(baseval, USECS_IN_SECOND);
10861 		fval = bbr_filter_len_sec * USECS_IN_SECOND;
10862 		if (bbr_is_ratio == 0) {
10863 			if (fval > bbr_rtt_probe_limit)
10864 				newval = cur_rttp + (fval - bbr_rtt_probe_limit);
10865 			else
10866 				newval = cur_rttp;
10867 		} else {
10868 			int mul;
10869 
10870 			mul = fval / bbr_rtt_probe_limit;
10871 			newval = cur_rttp * mul;
10872 		}
10873 		if (cur_rttp > 	bbr->r_ctl.rc_probertt_int) {
10874 			bbr->r_ctl.rc_probertt_int = cur_rttp;
10875 			reset_time_small(&bbr->r_ctl.rc_rttprop, newval);
10876 			val = 1;
10877 		} else {
10878 			/*
10879 			 * No adjustments were made
10880 			 * do we need to shrink it?
10881 			 */
10882 			if (bbr->r_ctl.rc_probertt_int > bbr_rtt_probe_limit) {
10883 				if (cur_rttp <= bbr_rtt_probe_limit) {
10884 					/*
10885 					 * Things have calmed down lets
10886 					 * shrink all the way to default
10887 					 */
10888 					bbr->r_ctl.rc_probertt_int = bbr_rtt_probe_limit;
10889 					reset_time_small(&bbr->r_ctl.rc_rttprop,
10890 							 (bbr_filter_len_sec * USECS_IN_SECOND));
10891 					cur_rttp = bbr_rtt_probe_limit;
10892 					newval = (bbr_filter_len_sec * USECS_IN_SECOND);
10893 					val = 2;
10894 				} else {
10895 					/*
10896 					 * Well does some adjustment make sense?
10897 					 */
10898 					if (cur_rttp < bbr->r_ctl.rc_probertt_int) {
10899 						/* We can reduce interval time some */
10900 						bbr->r_ctl.rc_probertt_int = cur_rttp;
10901 						reset_time_small(&bbr->r_ctl.rc_rttprop, newval);
10902 						val = 3;
10903 					}
10904 				}
10905 			}
10906 		}
10907 		if (val)
10908 			bbr_log_rtt_shrinks(bbr, cts, cur_rttp, newval, __LINE__, BBR_RTTS_RESETS_VALUES, val);
10909 	}
10910 }
10911 
10912 static void
10913 bbr_exit_probe_rtt(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t cts)
10914 {
10915 	/* Exit probe-rtt */
10916 
10917 	if (tp->snd_cwnd < bbr->r_ctl.rc_saved_cwnd) {
10918 		tp->snd_cwnd = bbr->r_ctl.rc_saved_cwnd;
10919 		bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
10920 	}
10921 	bbr_log_exit_gain(bbr, cts, 1);
10922 	bbr->rc_hit_state_1 = 0;
10923 	bbr->r_ctl.rc_rtt_shrinks = cts;
10924 	bbr->r_ctl.last_in_probertt = cts;
10925 	bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_RTTPROBE, 0);
10926 	bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
10927 	bbr->r_ctl.r_app_limited_until = (ctf_flight_size(tp,
10928 					      (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes)) +
10929 					  bbr->r_ctl.rc_delivered);
10930 	if (SEQ_GT(cts, bbr->r_ctl.rc_bbr_state_time)) {
10931 		uint32_t time_in;
10932 
10933 		time_in = cts - bbr->r_ctl.rc_bbr_state_time;
10934 		counter_u64_add(bbr_state_time[bbr->rc_bbr_state], time_in);
10935 	}
10936 	if (bbr->rc_filled_pipe) {
10937 		/* Switch to probe_bw */
10938 		bbr->rc_bbr_state = BBR_STATE_PROBE_BW;
10939 		bbr->rc_bbr_substate = bbr_pick_probebw_substate(bbr, cts);
10940 		bbr->r_ctl.rc_bbr_cwnd_gain = bbr_cwnd_gain;
10941 		bbr_substate_change(bbr, cts, __LINE__, 0);
10942 		bbr_log_type_statechange(bbr, cts, __LINE__);
10943 	} else {
10944 		/* Back to startup */
10945 		bbr->rc_bbr_state = BBR_STATE_STARTUP;
10946 		bbr->r_ctl.rc_bbr_state_time = cts;
10947 		/*
10948 		 * We don't want to give a complete free 3
10949 		 * measurements until we exit, so we use
10950 		 * the number of pe's we were in probe-rtt
10951 		 * to add to the startup_epoch. That way
10952 		 * we will still retain the old state.
10953 		 */
10954 		bbr->r_ctl.rc_bbr_last_startup_epoch += (bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_pe_of_prtt);
10955 		bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
10956 		/* Make sure to use the lower pg when shifting back in */
10957 		if (bbr->r_ctl.rc_lost &&
10958 		    bbr_use_lower_gain_in_startup &&
10959 		    (bbr->rc_use_google == 0))
10960 			bbr->r_ctl.rc_bbr_hptsi_gain = bbr_startup_lower;
10961 		else
10962 			bbr->r_ctl.rc_bbr_hptsi_gain = bbr->r_ctl.rc_startup_pg;
10963 		bbr->r_ctl.rc_bbr_cwnd_gain = bbr->r_ctl.rc_startup_pg;
10964 		/* Probably not needed but set it anyway */
10965 		bbr_set_state_target(bbr, __LINE__);
10966 		bbr_log_type_statechange(bbr, cts, __LINE__);
10967 		bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
10968 		    bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 0);
10969 	}
10970 	bbr_check_probe_rtt_limits(bbr, cts);
10971 }
10972 
10973 static int32_t inline
10974 bbr_should_enter_probe_rtt(struct tcp_bbr *bbr, uint32_t cts)
10975 {
10976 	if ((bbr->rc_past_init_win == 1) &&
10977 	    (bbr->rc_in_persist == 0) &&
10978 	    (bbr_calc_time(cts, bbr->r_ctl.rc_rtt_shrinks) >= bbr->r_ctl.rc_probertt_int)) {
10979 		return (1);
10980 	}
10981 	if (bbr_can_force_probertt &&
10982 	    (bbr->rc_in_persist == 0) &&
10983 	    (TSTMP_GT(cts, bbr->r_ctl.last_in_probertt)) &&
10984 	    ((cts - bbr->r_ctl.last_in_probertt) > bbr->r_ctl.rc_probertt_int)) {
10985 		return (1);
10986 	}
10987 	return (0);
10988 }
10989 
10990 static int32_t
10991 bbr_google_startup(struct tcp_bbr *bbr, uint32_t cts, int32_t  pkt_epoch)
10992 {
10993 	uint64_t btlbw, gain;
10994 	if (pkt_epoch == 0) {
10995 		/*
10996 		 * Need to be on a pkt-epoch to continue.
10997 		 */
10998 		return (0);
10999 	}
11000 	btlbw = bbr_get_full_bw(bbr);
11001 	gain = ((bbr->r_ctl.rc_bbr_lastbtlbw *
11002 		 (uint64_t)bbr_start_exit) / (uint64_t)100) + bbr->r_ctl.rc_bbr_lastbtlbw;
11003 	if (btlbw >= gain) {
11004 		bbr->r_ctl.rc_bbr_last_startup_epoch = bbr->r_ctl.rc_pkt_epoch;
11005 		bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11006 				      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 3);
11007 		bbr->r_ctl.rc_bbr_lastbtlbw = btlbw;
11008 	}
11009 	if ((bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_bbr_last_startup_epoch) >= BBR_STARTUP_EPOCHS)
11010 		return (1);
11011 	bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11012 			      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 8);
11013 	return(0);
11014 }
11015 
11016 static int32_t inline
11017 bbr_state_startup(struct tcp_bbr *bbr, uint32_t cts, int32_t epoch, int32_t pkt_epoch)
11018 {
11019 	/* Have we gained 25% in the last 3 packet based epoch's? */
11020 	uint64_t btlbw, gain;
11021 	int do_exit;
11022 	int delta, rtt_gain;
11023 
11024 	if ((bbr->rc_tp->snd_una == bbr->rc_tp->snd_max) &&
11025 	    (bbr_calc_time(cts, bbr->r_ctl.rc_went_idle_time) >= bbr_rtt_probe_time)) {
11026 		/*
11027 		 * This qualifies as a RTT_PROBE session since we drop the
11028 		 * data outstanding to nothing and waited more than
11029 		 * bbr_rtt_probe_time.
11030 		 */
11031 		bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_WASIDLE, 0);
11032 		bbr_set_reduced_rtt(bbr, cts, __LINE__);
11033 	}
11034 	if (bbr_should_enter_probe_rtt(bbr, cts)) {
11035 		bbr_enter_probe_rtt(bbr, cts, __LINE__);
11036 		return (0);
11037 	}
11038 	if (bbr->rc_use_google)
11039 		return (bbr_google_startup(bbr, cts,  pkt_epoch));
11040 
11041 	if ((bbr->r_ctl.rc_lost > bbr->r_ctl.rc_lost_at_startup) &&
11042 	    (bbr_use_lower_gain_in_startup)) {
11043 		/* Drop to a lower gain 1.5 x since we saw loss */
11044 		bbr->r_ctl.rc_bbr_hptsi_gain = bbr_startup_lower;
11045 	}
11046 	if (pkt_epoch == 0) {
11047 		/*
11048 		 * Need to be on a pkt-epoch to continue.
11049 		 */
11050 		return (0);
11051 	}
11052 	if (bbr_rtt_gain_thresh) {
11053 		/*
11054 		 * Do we allow a flow to stay
11055 		 * in startup with no loss and no
11056 		 * gain in rtt over a set threshold?
11057 		 */
11058 		if (bbr->r_ctl.rc_pkt_epoch_rtt &&
11059 		    bbr->r_ctl.startup_last_srtt &&
11060 		    (bbr->r_ctl.rc_pkt_epoch_rtt > bbr->r_ctl.startup_last_srtt)) {
11061 			delta = bbr->r_ctl.rc_pkt_epoch_rtt - bbr->r_ctl.startup_last_srtt;
11062 			rtt_gain = (delta * 100) / bbr->r_ctl.startup_last_srtt;
11063 		} else
11064 			rtt_gain = 0;
11065 		if ((bbr->r_ctl.startup_last_srtt == 0)  ||
11066 		    (bbr->r_ctl.rc_pkt_epoch_rtt < bbr->r_ctl.startup_last_srtt))
11067 			/* First time or new lower value */
11068 			bbr->r_ctl.startup_last_srtt = bbr->r_ctl.rc_pkt_epoch_rtt;
11069 
11070 		if ((bbr->r_ctl.rc_lost == 0) &&
11071 		    (rtt_gain < bbr_rtt_gain_thresh)) {
11072 			/*
11073 			 * No loss, and we are under
11074 			 * our gain threhold for
11075 			 * increasing RTT.
11076 			 */
11077 			if (bbr->r_ctl.rc_bbr_last_startup_epoch < bbr->r_ctl.rc_pkt_epoch)
11078 				bbr->r_ctl.rc_bbr_last_startup_epoch++;
11079 			bbr_log_startup_event(bbr, cts, rtt_gain,
11080 					      delta, bbr->r_ctl.startup_last_srtt, 10);
11081 			return (0);
11082 		}
11083 	}
11084 	if ((bbr->r_ctl.r_measurement_count == bbr->r_ctl.last_startup_measure) &&
11085 	    (bbr->r_ctl.rc_lost_at_startup == bbr->r_ctl.rc_lost) &&
11086 	    (!IN_RECOVERY(bbr->rc_tp->t_flags))) {
11087 		/*
11088 		 * We only assess if we have a new measurment when
11089 		 * we have no loss and are not in recovery.
11090 		 * Drag up by one our last_startup epoch so we will hold
11091 		 * the number of non-gain we have already accumulated.
11092 		 */
11093 		if (bbr->r_ctl.rc_bbr_last_startup_epoch < bbr->r_ctl.rc_pkt_epoch)
11094 			bbr->r_ctl.rc_bbr_last_startup_epoch++;
11095 		bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11096 				      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 9);
11097 		return (0);
11098 	}
11099 	/* Case where we reduced the lost (bad retransmit) */
11100 	if (bbr->r_ctl.rc_lost_at_startup > bbr->r_ctl.rc_lost)
11101 		bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
11102 	bbr->r_ctl.last_startup_measure = bbr->r_ctl.r_measurement_count;
11103 	btlbw = bbr_get_full_bw(bbr);
11104 	if (bbr->r_ctl.rc_bbr_hptsi_gain == bbr_startup_lower)
11105 		gain = ((bbr->r_ctl.rc_bbr_lastbtlbw *
11106 			 (uint64_t)bbr_low_start_exit) / (uint64_t)100) + bbr->r_ctl.rc_bbr_lastbtlbw;
11107 	else
11108 		gain = ((bbr->r_ctl.rc_bbr_lastbtlbw *
11109 			 (uint64_t)bbr_start_exit) / (uint64_t)100) + bbr->r_ctl.rc_bbr_lastbtlbw;
11110 	do_exit = 0;
11111 	if (btlbw > bbr->r_ctl.rc_bbr_lastbtlbw)
11112 		bbr->r_ctl.rc_bbr_lastbtlbw = btlbw;
11113 	if (btlbw >= gain) {
11114 		bbr->r_ctl.rc_bbr_last_startup_epoch = bbr->r_ctl.rc_pkt_epoch;
11115 		/* Update the lost so we won't exit in next set of tests */
11116 		bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
11117 		bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11118 				      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 3);
11119 	}
11120 	if ((bbr->rc_loss_exit &&
11121 	     (bbr->r_ctl.rc_lost > bbr->r_ctl.rc_lost_at_startup) &&
11122 	     (bbr->r_ctl.rc_pkt_epoch_loss_rate > bbr_startup_loss_thresh)) &&
11123 	    ((bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_bbr_last_startup_epoch) >= BBR_STARTUP_EPOCHS)) {
11124 		/*
11125 		 * If we had no gain,  we had loss and that loss was above
11126 		 * our threshould, the rwnd is not constrained, and we have
11127 		 * had at least 3 packet epochs exit. Note that this is
11128 		 * switched off by sysctl. Google does not do this by the
11129 		 * way.
11130 		 */
11131 		if ((ctf_flight_size(bbr->rc_tp,
11132 			 (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes)) +
11133 		     (2 * max(bbr->r_ctl.rc_pace_max_segs, bbr->rc_tp->t_maxseg))) <= bbr->rc_tp->snd_wnd) {
11134 			do_exit = 1;
11135 			bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11136 					      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 4);
11137 		} else {
11138 			/* Just record an updated loss value */
11139 			bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
11140 			bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11141 					      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 5);
11142 		}
11143 	} else
11144 		bbr->r_ctl.rc_lost_at_startup = bbr->r_ctl.rc_lost;
11145 	if (((bbr->r_ctl.rc_pkt_epoch - bbr->r_ctl.rc_bbr_last_startup_epoch) >= BBR_STARTUP_EPOCHS) ||
11146 	    do_exit) {
11147 		/* Return 1 to exit the startup state. */
11148 		return (1);
11149 	}
11150 	/* Stay in startup */
11151 	bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11152 			      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 8);
11153 	return (0);
11154 }
11155 
11156 static void
11157 bbr_state_change(struct tcp_bbr *bbr, uint32_t cts, int32_t epoch, int32_t pkt_epoch, uint32_t losses)
11158 {
11159 	/*
11160 	 * A tick occured in the rtt epoch do we need to do anything?
11161 	 */
11162 #ifdef BBR_INVARIANTS
11163 	if ((bbr->rc_bbr_state != BBR_STATE_STARTUP) &&
11164 	    (bbr->rc_bbr_state != BBR_STATE_DRAIN) &&
11165 	    (bbr->rc_bbr_state != BBR_STATE_PROBE_RTT) &&
11166 	    (bbr->rc_bbr_state != BBR_STATE_IDLE_EXIT) &&
11167 	    (bbr->rc_bbr_state != BBR_STATE_PROBE_BW)) {
11168 		/* Debug code? */
11169 		panic("Unknown BBR state %d?\n", bbr->rc_bbr_state);
11170 	}
11171 #endif
11172 	if (bbr->rc_bbr_state == BBR_STATE_STARTUP) {
11173 		/* Do we exit the startup state? */
11174 		if (bbr_state_startup(bbr, cts, epoch, pkt_epoch)) {
11175 			uint32_t time_in;
11176 
11177 			bbr_log_startup_event(bbr, cts, bbr->r_ctl.rc_bbr_last_startup_epoch,
11178 					      bbr->r_ctl.rc_lost_at_startup, bbr_start_exit, 6);
11179 			bbr->rc_filled_pipe = 1;
11180 			bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
11181 			if (SEQ_GT(cts, bbr->r_ctl.rc_bbr_state_time)) {
11182 				time_in = cts - bbr->r_ctl.rc_bbr_state_time;
11183 				counter_u64_add(bbr_state_time[bbr->rc_bbr_state], time_in);
11184 			} else
11185 				time_in = 0;
11186 			if (bbr->rc_no_pacing)
11187 				bbr->rc_no_pacing = 0;
11188 			bbr->r_ctl.rc_bbr_state_time = cts;
11189 			bbr->r_ctl.rc_bbr_hptsi_gain = bbr->r_ctl.rc_drain_pg;
11190 			bbr->rc_bbr_state = BBR_STATE_DRAIN;
11191 			bbr_set_state_target(bbr, __LINE__);
11192 			if ((bbr->rc_use_google == 0) &&
11193 			    bbr_slam_cwnd_in_main_drain) {
11194 				/* Here we don't have to worry about probe-rtt */
11195 				bbr->r_ctl.rc_saved_cwnd = bbr->rc_tp->snd_cwnd;
11196 				bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_target_at_state;
11197 				bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
11198 			}
11199 			bbr->r_ctl.rc_bbr_cwnd_gain = bbr_high_gain;
11200 			bbr_log_type_statechange(bbr, cts, __LINE__);
11201 			if (ctf_flight_size(bbr->rc_tp,
11202 			        (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes)) <=
11203 			    bbr->r_ctl.rc_target_at_state) {
11204 				/*
11205 				 * Switch to probe_bw if we are already
11206 				 * there
11207 				 */
11208 				bbr->rc_bbr_substate = bbr_pick_probebw_substate(bbr, cts);
11209 				bbr_substate_change(bbr, cts, __LINE__, 0);
11210 				bbr->rc_bbr_state = BBR_STATE_PROBE_BW;
11211 				bbr_log_type_statechange(bbr, cts, __LINE__);
11212 			}
11213 		}
11214 	} else if (bbr->rc_bbr_state == BBR_STATE_IDLE_EXIT) {
11215 		uint32_t inflight;
11216 		struct tcpcb *tp;
11217 
11218 		tp = bbr->rc_tp;
11219 		inflight = ctf_flight_size(tp,
11220 			      (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
11221 		if (inflight >= bbr->r_ctl.rc_target_at_state) {
11222 			/* We have reached a flight of the cwnd target */
11223 			bbr->rc_bbr_state = BBR_STATE_PROBE_BW;
11224 			bbr->r_ctl.rc_bbr_hptsi_gain = BBR_UNIT;
11225 			bbr->r_ctl.rc_bbr_cwnd_gain = BBR_UNIT;
11226 			bbr_set_state_target(bbr, __LINE__);
11227 			/*
11228 			 * Rig it so we don't do anything crazy and
11229 			 * start fresh with a new randomization.
11230 			 */
11231 			bbr->r_ctl.bbr_smallest_srtt_this_state = 0xffffffff;
11232 			bbr->rc_bbr_substate = BBR_SUB_LEVEL6;
11233 			bbr_substate_change(bbr, cts, __LINE__, 1);
11234 		}
11235 	} else if (bbr->rc_bbr_state == BBR_STATE_DRAIN) {
11236 		/* Has in-flight reached the bdp (or less)? */
11237 		uint32_t inflight;
11238 		struct tcpcb *tp;
11239 
11240 		tp = bbr->rc_tp;
11241 		inflight = ctf_flight_size(tp,
11242 			      (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
11243 		if ((bbr->rc_use_google == 0) &&
11244 		    bbr_slam_cwnd_in_main_drain &&
11245 		    (bbr->rc_tp->snd_cwnd > bbr->r_ctl.rc_target_at_state)) {
11246 			/*
11247 			 * Here we don't have to worry about probe-rtt
11248 			 * re-slam it, but keep it slammed down.
11249 			 */
11250 			bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_target_at_state;
11251 			bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
11252 		}
11253 		if (inflight <= bbr->r_ctl.rc_target_at_state) {
11254 			/* We have drained */
11255 			bbr->rc_bbr_state = BBR_STATE_PROBE_BW;
11256 			bbr->r_ctl.bbr_lost_at_state = bbr->r_ctl.rc_lost;
11257 			if (SEQ_GT(cts, bbr->r_ctl.rc_bbr_state_time)) {
11258 				uint32_t time_in;
11259 
11260 				time_in = cts - bbr->r_ctl.rc_bbr_state_time;
11261 				counter_u64_add(bbr_state_time[bbr->rc_bbr_state], time_in);
11262 			}
11263 			if ((bbr->rc_use_google == 0) &&
11264 			    bbr_slam_cwnd_in_main_drain &&
11265 			    (tp->snd_cwnd < bbr->r_ctl.rc_saved_cwnd)) {
11266 				/* Restore the cwnd */
11267 				tp->snd_cwnd = bbr->r_ctl.rc_saved_cwnd;
11268 				bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
11269 			}
11270 			/* Setup probe-rtt has being done now RRS-HERE */
11271 			bbr->r_ctl.rc_rtt_shrinks = cts;
11272 			bbr->r_ctl.last_in_probertt = cts;
11273 			bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_LEAVE_DRAIN, 0);
11274 			/* Randomly pick a sub-state */
11275 			bbr->rc_bbr_substate = bbr_pick_probebw_substate(bbr, cts);
11276 			bbr_substate_change(bbr, cts, __LINE__, 0);
11277 			bbr_log_type_statechange(bbr, cts, __LINE__);
11278 		}
11279 	} else if (bbr->rc_bbr_state == BBR_STATE_PROBE_RTT) {
11280 		uint32_t flight;
11281 
11282 		flight = ctf_flight_size(bbr->rc_tp,
11283 			     (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
11284 		bbr->r_ctl.r_app_limited_until = (flight + bbr->r_ctl.rc_delivered);
11285 		if (((bbr->r_ctl.bbr_rttprobe_gain_val == 0) || bbr->rc_use_google) &&
11286 		    (bbr->rc_tp->snd_cwnd > bbr->r_ctl.rc_target_at_state)) {
11287 			/*
11288 			 * We must keep cwnd at the desired MSS.
11289 			 */
11290 			bbr->rc_tp->snd_cwnd = bbr_rtt_probe_cwndtarg * (bbr->rc_tp->t_maxseg - bbr->rc_last_options);
11291 			bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
11292 		} else if ((bbr_prtt_slam_cwnd) &&
11293 			   (bbr->rc_tp->snd_cwnd > bbr->r_ctl.rc_target_at_state)) {
11294 			/* Re-slam it */
11295 			bbr->rc_tp->snd_cwnd = bbr->r_ctl.rc_target_at_state;
11296 			bbr_log_type_cwndupd(bbr, 0, 0, 0, 12, 0, 0, __LINE__);
11297 		}
11298 		if (bbr->r_ctl.rc_bbr_enters_probertt == 0) {
11299 			/* Has outstanding reached our target? */
11300 			if (flight <= bbr->r_ctl.rc_target_at_state) {
11301 				bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_REACHTAR, 0);
11302 				bbr->r_ctl.rc_bbr_enters_probertt = cts;
11303 				/* If time is exactly 0, be 1usec off */
11304 				if (bbr->r_ctl.rc_bbr_enters_probertt == 0)
11305 					bbr->r_ctl.rc_bbr_enters_probertt = 1;
11306 				if (bbr->rc_use_google == 0) {
11307 					/*
11308 					 * Restore any lowering that as occured to
11309 					 * reach here
11310 					 */
11311 					if (bbr->r_ctl.bbr_rttprobe_gain_val)
11312 						bbr->r_ctl.rc_bbr_hptsi_gain = bbr->r_ctl.bbr_rttprobe_gain_val;
11313 					else
11314 						bbr->r_ctl.rc_bbr_hptsi_gain = BBR_UNIT;
11315 				}
11316 			}
11317 			if ((bbr->r_ctl.rc_bbr_enters_probertt == 0) &&
11318 			    (bbr->rc_use_google == 0) &&
11319 			    bbr->r_ctl.bbr_rttprobe_gain_val &&
11320 			    (((cts - bbr->r_ctl.rc_probertt_srttchktim) > bbr_get_rtt(bbr, bbr_drain_rtt)) ||
11321 			     (flight >= bbr->r_ctl.flightsize_at_drain))) {
11322 				/*
11323 				 * We have doddled with our current hptsi
11324 				 * gain an srtt and have still not made it
11325 				 * to target, or we have increased our flight.
11326 				 * Lets reduce the gain by xx%
11327 				 * flooring the reduce at DRAIN (based on
11328 				 * mul/div)
11329 				 */
11330 				int red;
11331 
11332 				bbr->r_ctl.flightsize_at_drain = flight;
11333 				bbr->r_ctl.rc_probertt_srttchktim = cts;
11334 				red = max((bbr->r_ctl.bbr_rttprobe_gain_val / 10), 1);
11335 				if ((bbr->r_ctl.rc_bbr_hptsi_gain - red) > max(bbr_drain_floor, 1)) {
11336 					/* Reduce our gain again */
11337 					bbr->r_ctl.rc_bbr_hptsi_gain -= red;
11338 					bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_SHRINK_PG, 0);
11339 				} else if (bbr->r_ctl.rc_bbr_hptsi_gain > max(bbr_drain_floor, 1)) {
11340 					/* one more chance before we give up */
11341 					bbr->r_ctl.rc_bbr_hptsi_gain = max(bbr_drain_floor, 1);
11342 					bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_SHRINK_PG_FINAL, 0);
11343 				} else {
11344 					/* At the very bottom */
11345 					bbr->r_ctl.rc_bbr_hptsi_gain = max((bbr_drain_floor-1), 1);
11346 				}
11347 			}
11348 		}
11349 		if (bbr->r_ctl.rc_bbr_enters_probertt &&
11350 		    (TSTMP_GT(cts, bbr->r_ctl.rc_bbr_enters_probertt)) &&
11351 		    ((cts - bbr->r_ctl.rc_bbr_enters_probertt) >= bbr_rtt_probe_time)) {
11352 			/* Time to exit probe RTT normally */
11353 			bbr_exit_probe_rtt(bbr->rc_tp, bbr, cts);
11354 		}
11355 	} else if (bbr->rc_bbr_state == BBR_STATE_PROBE_BW) {
11356 		if ((bbr->rc_tp->snd_una == bbr->rc_tp->snd_max) &&
11357 		    (bbr_calc_time(cts, bbr->r_ctl.rc_went_idle_time) >= bbr_rtt_probe_time)) {
11358 			/*
11359 			 * This qualifies as a RTT_PROBE session since we
11360 			 * drop the data outstanding to nothing and waited
11361 			 * more than bbr_rtt_probe_time.
11362 			 */
11363 			bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_WASIDLE, 0);
11364 			bbr_set_reduced_rtt(bbr, cts, __LINE__);
11365 		}
11366 		if (bbr_should_enter_probe_rtt(bbr, cts)) {
11367 			bbr_enter_probe_rtt(bbr, cts, __LINE__);
11368 		} else {
11369 			bbr_set_probebw_gains(bbr, cts, losses);
11370 		}
11371 	}
11372 }
11373 
11374 static void
11375 bbr_check_bbr_for_state(struct tcp_bbr *bbr, uint32_t cts, int32_t line, uint32_t losses)
11376 {
11377 	int32_t epoch = 0;
11378 
11379 	if ((cts - bbr->r_ctl.rc_rcv_epoch_start) >= bbr_get_rtt(bbr, BBR_RTT_PROP)) {
11380 		bbr_set_epoch(bbr, cts, line);
11381 		/* At each epoch doe lt bw sampling */
11382 		epoch = 1;
11383 	}
11384 	bbr_state_change(bbr, cts, epoch, bbr->rc_is_pkt_epoch_now, losses);
11385 }
11386 
11387 static int
11388 bbr_do_segment_nounlock(struct mbuf *m, struct tcphdr *th, struct socket *so,
11389     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos,
11390     int32_t nxt_pkt, struct timeval *tv)
11391 {
11392 	int32_t thflags, retval;
11393 	uint32_t cts, lcts;
11394 	uint32_t tiwin;
11395 	struct tcpopt to;
11396 	struct tcp_bbr *bbr;
11397 	struct bbr_sendmap *rsm;
11398 	struct timeval ltv;
11399 	int32_t did_out = 0;
11400 	int32_t in_recovery;
11401 	uint16_t nsegs;
11402 	int32_t prev_state;
11403 	uint32_t lost;
11404 
11405 	nsegs = max(1, m->m_pkthdr.lro_nsegs);
11406 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
11407 	/* add in our stats */
11408 	kern_prefetch(bbr, &prev_state);
11409 	prev_state = 0;
11410 	thflags = th->th_flags;
11411 	/*
11412 	 * If this is either a state-changing packet or current state isn't
11413 	 * established, we require a write lock on tcbinfo.  Otherwise, we
11414 	 * allow the tcbinfo to be in either alocked or unlocked, as the
11415 	 * caller may have unnecessarily acquired a write lock due to a
11416 	 * race.
11417 	 */
11418 	INP_WLOCK_ASSERT(tp->t_inpcb);
11419 	KASSERT(tp->t_state > TCPS_LISTEN, ("%s: TCPS_LISTEN",
11420 	    __func__));
11421 	KASSERT(tp->t_state != TCPS_TIME_WAIT, ("%s: TCPS_TIME_WAIT",
11422 	    __func__));
11423 
11424 	tp->t_rcvtime = ticks;
11425 	/*
11426 	 * Unscale the window into a 32-bit value. For the SYN_SENT state
11427 	 * the scale is zero.
11428 	 */
11429 	tiwin = th->th_win << tp->snd_scale;
11430 #ifdef STATS
11431 	stats_voi_update_abs_ulong(tp->t_stats, VOI_TCP_FRWIN, tiwin);
11432 #endif
11433 
11434 	if (m->m_flags & M_TSTMP) {
11435 		/* Prefer the hardware timestamp if present */
11436 		struct timespec ts;
11437 
11438 		mbuf_tstmp2timespec(m, &ts);
11439 		bbr->rc_tv.tv_sec = ts.tv_sec;
11440 		bbr->rc_tv.tv_usec = ts.tv_nsec / 1000;
11441 		bbr->r_ctl.rc_rcvtime = cts = tcp_tv_to_usectick(&bbr->rc_tv);
11442 	} else if (m->m_flags & M_TSTMP_LRO) {
11443 		/* Next the arrival timestamp */
11444 		struct timespec ts;
11445 
11446 		mbuf_tstmp2timespec(m, &ts);
11447 		bbr->rc_tv.tv_sec = ts.tv_sec;
11448 		bbr->rc_tv.tv_usec = ts.tv_nsec / 1000;
11449 		bbr->r_ctl.rc_rcvtime = cts = tcp_tv_to_usectick(&bbr->rc_tv);
11450 	} else {
11451 		/*
11452 		 * Ok just get the current time.
11453 		 */
11454 		bbr->r_ctl.rc_rcvtime = lcts = cts = tcp_get_usecs(&bbr->rc_tv);
11455 	}
11456 	/*
11457 	 * Parse options on any incoming segment.
11458 	 */
11459 	tcp_dooptions(&to, (u_char *)(th + 1),
11460 	    (th->th_off << 2) - sizeof(struct tcphdr),
11461 	    (thflags & TH_SYN) ? TO_SYN : 0);
11462 
11463 	/*
11464 	 * If timestamps were negotiated during SYN/ACK and a
11465 	 * segment without a timestamp is received, silently drop
11466 	 * the segment.
11467 	 * See section 3.2 of RFC 7323.
11468 	 */
11469 	if ((tp->t_flags & TF_RCVD_TSTMP) && !(to.to_flags & TOF_TS)) {
11470 		retval = 0;
11471 		goto done_with_input;
11472 	}
11473 	/*
11474 	 * If echoed timestamp is later than the current time, fall back to
11475 	 * non RFC1323 RTT calculation.  Normalize timestamp if syncookies
11476 	 * were used when this connection was established.
11477 	 */
11478 	if ((to.to_flags & TOF_TS) && (to.to_tsecr != 0)) {
11479 		to.to_tsecr -= tp->ts_offset;
11480 		if (TSTMP_GT(to.to_tsecr, tcp_tv_to_mssectick(&bbr->rc_tv)))
11481 			to.to_tsecr = 0;
11482 	}
11483 	/*
11484 	 * If its the first time in we need to take care of options and
11485 	 * verify we can do SACK for rack!
11486 	 */
11487 	if (bbr->r_state == 0) {
11488 		/*
11489 		 * Process options only when we get SYN/ACK back. The SYN
11490 		 * case for incoming connections is handled in tcp_syncache.
11491 		 * According to RFC1323 the window field in a SYN (i.e., a
11492 		 * <SYN> or <SYN,ACK>) segment itself is never scaled. XXX
11493 		 * this is traditional behavior, may need to be cleaned up.
11494 		 */
11495 		if (bbr->rc_inp == NULL) {
11496 			bbr->rc_inp = tp->t_inpcb;
11497 		}
11498 		/*
11499 		 * We need to init rc_inp here since its not init'd when
11500 		 * bbr_init is called
11501 		 */
11502 		if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) {
11503 			if ((to.to_flags & TOF_SCALE) &&
11504 			    (tp->t_flags & TF_REQ_SCALE)) {
11505 				tp->t_flags |= TF_RCVD_SCALE;
11506 				tp->snd_scale = to.to_wscale;
11507 			} else
11508 				tp->t_flags &= ~TF_REQ_SCALE;
11509 			/*
11510 			 * Initial send window.  It will be updated with the
11511 			 * next incoming segment to the scaled value.
11512 			 */
11513 			tp->snd_wnd = th->th_win;
11514 			if ((to.to_flags & TOF_TS) &&
11515 			    (tp->t_flags & TF_REQ_TSTMP)) {
11516 				tp->t_flags |= TF_RCVD_TSTMP;
11517 				tp->ts_recent = to.to_tsval;
11518 				tp->ts_recent_age = tcp_tv_to_mssectick(&bbr->rc_tv);
11519 			} else
11520 			    tp->t_flags &= ~TF_REQ_TSTMP;
11521 			if (to.to_flags & TOF_MSS)
11522 				tcp_mss(tp, to.to_mss);
11523 			if ((tp->t_flags & TF_SACK_PERMIT) &&
11524 			    (to.to_flags & TOF_SACKPERM) == 0)
11525 				tp->t_flags &= ~TF_SACK_PERMIT;
11526 			if (IS_FASTOPEN(tp->t_flags)) {
11527 				if (to.to_flags & TOF_FASTOPEN) {
11528 					uint16_t mss;
11529 
11530 					if (to.to_flags & TOF_MSS)
11531 						mss = to.to_mss;
11532 					else
11533 						if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
11534 							mss = TCP6_MSS;
11535 						else
11536 							mss = TCP_MSS;
11537 					tcp_fastopen_update_cache(tp, mss,
11538 					    to.to_tfo_len, to.to_tfo_cookie);
11539 				} else
11540 					tcp_fastopen_disable_path(tp);
11541 			}
11542 		}
11543 		/*
11544 		 * At this point we are at the initial call. Here we decide
11545 		 * if we are doing RACK or not. We do this by seeing if
11546 		 * TF_SACK_PERMIT is set, if not rack is *not* possible and
11547 		 * we switch to the default code.
11548 		 */
11549 		if ((tp->t_flags & TF_SACK_PERMIT) == 0) {
11550 			/* Bail */
11551 			tcp_switch_back_to_default(tp);
11552 			(*tp->t_fb->tfb_tcp_do_segment) (m, th, so, tp, drop_hdrlen,
11553 			    tlen, iptos);
11554 			return (1);
11555 		}
11556 		/* Set the flag */
11557 		bbr->r_is_v6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0;
11558 		tcp_set_hpts(tp->t_inpcb);
11559 		sack_filter_clear(&bbr->r_ctl.bbr_sf, th->th_ack);
11560 	}
11561 	if (thflags & TH_ACK) {
11562 		/* Track ack types */
11563 		if (to.to_flags & TOF_SACK)
11564 			BBR_STAT_INC(bbr_acks_with_sacks);
11565 		else
11566 			BBR_STAT_INC(bbr_plain_acks);
11567 	}
11568 	/*
11569 	 * This is the one exception case where we set the rack state
11570 	 * always. All other times (timers etc) we must have a rack-state
11571 	 * set (so we assure we have done the checks above for SACK).
11572 	 */
11573 	if (thflags & TH_FIN)
11574 		tcp_log_end_status(tp, TCP_EI_STATUS_CLIENT_FIN);
11575 	if (bbr->r_state != tp->t_state)
11576 		bbr_set_state(tp, bbr, tiwin);
11577 
11578 	if (SEQ_GT(th->th_ack, tp->snd_una) && (rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map)) != NULL)
11579 		kern_prefetch(rsm, &prev_state);
11580 	prev_state = bbr->r_state;
11581 	bbr->rc_ack_was_delayed = 0;
11582 	lost = bbr->r_ctl.rc_lost;
11583 	bbr->rc_is_pkt_epoch_now = 0;
11584 	if (m->m_flags & (M_TSTMP|M_TSTMP_LRO)) {
11585 		/* Get the real time into lcts and figure the real delay */
11586 		lcts = tcp_get_usecs(&ltv);
11587 		if (TSTMP_GT(lcts, cts)) {
11588 			bbr->r_ctl.rc_ack_hdwr_delay = lcts - cts;
11589 			bbr->rc_ack_was_delayed = 1;
11590 			if (TSTMP_GT(bbr->r_ctl.rc_ack_hdwr_delay,
11591 				     bbr->r_ctl.highest_hdwr_delay))
11592 				bbr->r_ctl.highest_hdwr_delay = bbr->r_ctl.rc_ack_hdwr_delay;
11593 		} else {
11594 			bbr->r_ctl.rc_ack_hdwr_delay = 0;
11595 			bbr->rc_ack_was_delayed = 0;
11596 		}
11597 	} else {
11598 		bbr->r_ctl.rc_ack_hdwr_delay = 0;
11599 		bbr->rc_ack_was_delayed = 0;
11600 	}
11601 	bbr_log_ack_event(bbr, th, &to, tlen, nsegs, cts, nxt_pkt, m);
11602 	if ((thflags & TH_SYN) && (thflags & TH_FIN) && V_drop_synfin) {
11603 		retval = 0;
11604 		m_freem(m);
11605                 goto done_with_input;
11606         }
11607         /*
11608          * If a segment with the ACK-bit set arrives in the SYN-SENT state
11609          * check SEQ.ACK first as described on page 66 of RFC 793, section 3.9.
11610          */
11611         if ((tp->t_state == TCPS_SYN_SENT) && (thflags & TH_ACK) &&
11612             (SEQ_LEQ(th->th_ack, tp->iss) || SEQ_GT(th->th_ack, tp->snd_max))) {
11613 		tcp_log_end_status(tp, TCP_EI_STATUS_RST_IN_FRONT);
11614 		ctf_do_dropwithreset_conn(m, tp, th, BANDLIM_RST_OPENPORT, tlen);
11615                 return (1);
11616         }
11617 	in_recovery = IN_RECOVERY(tp->t_flags);
11618 	if (tiwin > bbr->r_ctl.rc_high_rwnd)
11619 		bbr->r_ctl.rc_high_rwnd = tiwin;
11620 #ifdef BBR_INVARIANTS
11621 	if ((tp->t_inpcb->inp_flags & INP_DROPPED) ||
11622 	    (tp->t_inpcb->inp_flags2 & INP_FREED)) {
11623 		panic("tp:%p bbr:%p given a dropped inp:%p",
11624 		    tp, bbr, tp->t_inpcb);
11625 	}
11626 #endif
11627 	bbr->r_ctl.rc_flight_at_input = ctf_flight_size(tp,
11628 					    (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
11629 	bbr->rtt_valid = 0;
11630 	if (to.to_flags & TOF_TS) {
11631 		bbr->rc_ts_valid = 1;
11632 		bbr->r_ctl.last_inbound_ts = to.to_tsval;
11633 	} else {
11634 		bbr->rc_ts_valid = 0;
11635 		bbr->r_ctl.last_inbound_ts = 0;
11636 	}
11637 	retval = (*bbr->r_substate) (m, th, so,
11638 	    tp, &to, drop_hdrlen,
11639 	    tlen, tiwin, thflags, nxt_pkt, iptos);
11640 #ifdef BBR_INVARIANTS
11641 	if ((retval == 0) &&
11642 	    (tp->t_inpcb == NULL)) {
11643 		panic("retval:%d tp:%p t_inpcb:NULL state:%d",
11644 		    retval, tp, prev_state);
11645 	}
11646 #endif
11647 	if (nxt_pkt == 0)
11648 		BBR_STAT_INC(bbr_rlock_left_ret0);
11649 	else
11650 		BBR_STAT_INC(bbr_rlock_left_ret1);
11651 	if (retval == 0) {
11652 		/*
11653 		 * If retval is 1 the tcb is unlocked and most likely the tp
11654 		 * is gone.
11655 		 */
11656 		INP_WLOCK_ASSERT(tp->t_inpcb);
11657 		tcp_bbr_xmit_timer_commit(bbr, tp, cts);
11658 		if (bbr->rc_is_pkt_epoch_now)
11659 			bbr_set_pktepoch(bbr, cts, __LINE__);
11660 		bbr_check_bbr_for_state(bbr, cts, __LINE__, (bbr->r_ctl.rc_lost - lost));
11661 		if (nxt_pkt == 0) {
11662 			if (bbr->r_wanted_output != 0) {
11663 				bbr->rc_output_starts_timer = 0;
11664 				did_out = 1;
11665 				(void)tp->t_fb->tfb_tcp_output(tp);
11666 			} else
11667 				bbr_start_hpts_timer(bbr, tp, cts, 6, 0, 0);
11668 		}
11669 		if ((nxt_pkt == 0) &&
11670 		    ((bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK) == 0) &&
11671 		    (SEQ_GT(tp->snd_max, tp->snd_una) ||
11672 		     (tp->t_flags & TF_DELACK) ||
11673 		     ((V_tcp_always_keepalive || bbr->rc_inp->inp_socket->so_options & SO_KEEPALIVE) &&
11674 		      (tp->t_state <= TCPS_CLOSING)))) {
11675 			/*
11676 			 * We could not send (probably in the hpts but
11677 			 * stopped the timer)?
11678 			 */
11679 			if ((tp->snd_max == tp->snd_una) &&
11680 			    ((tp->t_flags & TF_DELACK) == 0) &&
11681 			    (bbr->rc_inp->inp_in_hpts) &&
11682 			    (bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
11683 				/*
11684 				 * keep alive not needed if we are hptsi
11685 				 * output yet
11686 				 */
11687 				;
11688 			} else {
11689 				if (bbr->rc_inp->inp_in_hpts) {
11690 					tcp_hpts_remove(bbr->rc_inp, HPTS_REMOVE_OUTPUT);
11691 					if ((bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
11692 					    (TSTMP_GT(lcts, bbr->rc_pacer_started))) {
11693 						uint32_t del;
11694 
11695 						del = lcts - bbr->rc_pacer_started;
11696 						if (bbr->r_ctl.rc_last_delay_val > del) {
11697 							BBR_STAT_INC(bbr_force_timer_start);
11698 							bbr->r_ctl.rc_last_delay_val -= del;
11699 							bbr->rc_pacer_started = lcts;
11700 						} else {
11701 							/* We are late */
11702 							bbr->r_ctl.rc_last_delay_val = 0;
11703 							BBR_STAT_INC(bbr_force_output);
11704 							(void)tp->t_fb->tfb_tcp_output(tp);
11705 						}
11706 					}
11707 				}
11708 				bbr_start_hpts_timer(bbr, tp, cts, 8, bbr->r_ctl.rc_last_delay_val,
11709 				    0);
11710 			}
11711 		} else if ((bbr->rc_output_starts_timer == 0) && (nxt_pkt == 0)) {
11712 			/* Do we have the correct timer running? */
11713 			bbr_timer_audit(tp, bbr, lcts, &so->so_snd);
11714 		}
11715 		/* Do we have a new state */
11716 		if (bbr->r_state != tp->t_state)
11717 			bbr_set_state(tp, bbr, tiwin);
11718 done_with_input:
11719 		bbr_log_doseg_done(bbr, cts, nxt_pkt, did_out);
11720 		if (did_out)
11721 			bbr->r_wanted_output = 0;
11722 #ifdef BBR_INVARIANTS
11723 		if (tp->t_inpcb == NULL) {
11724 			panic("OP:%d retval:%d tp:%p t_inpcb:NULL state:%d",
11725 			    did_out,
11726 			    retval, tp, prev_state);
11727 		}
11728 #endif
11729 	}
11730 	return (retval);
11731 }
11732 
11733 static void
11734 bbr_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
11735     struct tcpcb *tp, int32_t drop_hdrlen, int32_t tlen, uint8_t iptos)
11736 {
11737 	struct timeval tv;
11738 	int retval;
11739 
11740 	/* First lets see if we have old packets */
11741 	if (tp->t_in_pkt) {
11742 		if (ctf_do_queued_segments(so, tp, 1)) {
11743 			m_freem(m);
11744 			return;
11745 		}
11746 	}
11747 	if (m->m_flags & M_TSTMP_LRO) {
11748 		tv.tv_sec = m->m_pkthdr.rcv_tstmp /1000000000;
11749 		tv.tv_usec = (m->m_pkthdr.rcv_tstmp % 1000000000)/1000;
11750 	} else {
11751 		/* Should not be should we kassert instead? */
11752 		tcp_get_usecs(&tv);
11753 	}
11754 	retval = bbr_do_segment_nounlock(m, th, so, tp,
11755 					 drop_hdrlen, tlen, iptos, 0, &tv);
11756 	if (retval == 0) {
11757 		tcp_handle_wakeup(tp, so);
11758 		INP_WUNLOCK(tp->t_inpcb);
11759 	}
11760 }
11761 
11762 /*
11763  * Return how much data can be sent without violating the
11764  * cwnd or rwnd.
11765  */
11766 
11767 static inline uint32_t
11768 bbr_what_can_we_send(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t sendwin,
11769     uint32_t avail, int32_t sb_offset, uint32_t cts)
11770 {
11771 	uint32_t len;
11772 
11773 	if (ctf_outstanding(tp) >= tp->snd_wnd) {
11774 		/* We never want to go over our peers rcv-window */
11775 		len = 0;
11776 	} else {
11777 		uint32_t flight;
11778 
11779 		flight = ctf_flight_size(tp, (bbr->r_ctl.rc_sacked + bbr->r_ctl.rc_lost_bytes));
11780 		if (flight >= sendwin) {
11781 			/*
11782 			 * We have in flight what we are allowed by cwnd (if
11783 			 * it was rwnd blocking it would have hit above out
11784 			 * >= tp->snd_wnd).
11785 			 */
11786 			return (0);
11787 		}
11788 		len = sendwin - flight;
11789 		if ((len + ctf_outstanding(tp)) > tp->snd_wnd) {
11790 			/* We would send too much (beyond the rwnd) */
11791 			len = tp->snd_wnd - ctf_outstanding(tp);
11792 		}
11793 		if ((len + sb_offset) > avail) {
11794 			/*
11795 			 * We don't have that much in the SB, how much is
11796 			 * there?
11797 			 */
11798 			len = avail - sb_offset;
11799 		}
11800 	}
11801 	return (len);
11802 }
11803 
11804 static inline void
11805 bbr_do_error_accounting(struct tcpcb *tp, struct tcp_bbr *bbr, struct bbr_sendmap *rsm, int32_t len, int32_t error)
11806 {
11807 #ifdef NETFLIX_STATS
11808 	KMOD_TCPSTAT_INC(tcps_sndpack_error);
11809 	KMOD_TCPSTAT_ADD(tcps_sndbyte_error, len);
11810 #endif
11811 }
11812 
11813 static inline void
11814 bbr_do_send_accounting(struct tcpcb *tp, struct tcp_bbr *bbr, struct bbr_sendmap *rsm, int32_t len, int32_t error)
11815 {
11816 	if (error) {
11817 		bbr_do_error_accounting(tp, bbr, rsm, len, error);
11818 		return;
11819 	}
11820 	if (rsm) {
11821 		if (rsm->r_flags & BBR_TLP) {
11822 			/*
11823 			 * TLP should not count in retran count, but in its
11824 			 * own bin
11825 			 */
11826 #ifdef NETFLIX_STATS
11827 			tp->t_sndtlppack++;
11828 			tp->t_sndtlpbyte += len;
11829 			KMOD_TCPSTAT_INC(tcps_tlpresends);
11830 			KMOD_TCPSTAT_ADD(tcps_tlpresend_bytes, len);
11831 #endif
11832 		} else {
11833 			/* Retransmit */
11834 			tp->t_sndrexmitpack++;
11835 			KMOD_TCPSTAT_INC(tcps_sndrexmitpack);
11836 			KMOD_TCPSTAT_ADD(tcps_sndrexmitbyte, len);
11837 #ifdef STATS
11838 			stats_voi_update_abs_u32(tp->t_stats, VOI_TCP_RETXPB,
11839 			    len);
11840 #endif
11841 		}
11842 		/*
11843 		 * Logs in 0 - 8, 8 is all non probe_bw states 0-7 is
11844 		 * sub-state
11845 		 */
11846 		counter_u64_add(bbr_state_lost[rsm->r_bbr_state], len);
11847 		if (bbr->rc_bbr_state != BBR_STATE_PROBE_BW) {
11848 			/* Non probe_bw log in 1, 2, or 4. */
11849 			counter_u64_add(bbr_state_resend[bbr->rc_bbr_state], len);
11850 		} else {
11851 			/*
11852 			 * Log our probe state 3, and log also 5-13 to show
11853 			 * us the recovery sub-state for the send. This
11854 			 * means that 3 == (5+6+7+8+9+10+11+12+13)
11855 			 */
11856 			counter_u64_add(bbr_state_resend[BBR_STATE_PROBE_BW], len);
11857 			counter_u64_add(bbr_state_resend[(bbr_state_val(bbr) + 5)], len);
11858 		}
11859 		/* Place in both 16's the totals of retransmitted */
11860 		counter_u64_add(bbr_state_lost[16], len);
11861 		counter_u64_add(bbr_state_resend[16], len);
11862 		/* Place in 17's the total sent */
11863 		counter_u64_add(bbr_state_resend[17], len);
11864 		counter_u64_add(bbr_state_lost[17], len);
11865 
11866 	} else {
11867 		/* New sends */
11868 		KMOD_TCPSTAT_INC(tcps_sndpack);
11869 		KMOD_TCPSTAT_ADD(tcps_sndbyte, len);
11870 		/* Place in 17's the total sent */
11871 		counter_u64_add(bbr_state_resend[17], len);
11872 		counter_u64_add(bbr_state_lost[17], len);
11873 #ifdef STATS
11874 		stats_voi_update_abs_u64(tp->t_stats, VOI_TCP_TXPB,
11875 		    len);
11876 #endif
11877 	}
11878 }
11879 
11880 static void
11881 bbr_cwnd_limiting(struct tcpcb *tp, struct tcp_bbr *bbr, uint32_t in_level)
11882 {
11883 	if (bbr->rc_filled_pipe && bbr_target_cwnd_mult_limit && (bbr->rc_use_google == 0)) {
11884 		/*
11885 		 * Limit the cwnd to not be above N x the target plus whats
11886 		 * is outstanding. The target is based on the current b/w
11887 		 * estimate.
11888 		 */
11889 		uint32_t target;
11890 
11891 		target = bbr_get_target_cwnd(bbr, bbr_get_bw(bbr), BBR_UNIT);
11892 		target += ctf_outstanding(tp);
11893 		target *= bbr_target_cwnd_mult_limit;
11894 		if (tp->snd_cwnd > target)
11895 			tp->snd_cwnd = target;
11896 		bbr_log_type_cwndupd(bbr, 0, 0, 0, 10, 0, 0, __LINE__);
11897 	}
11898 }
11899 
11900 static int
11901 bbr_window_update_needed(struct tcpcb *tp, struct socket *so, uint32_t recwin, int32_t maxseg)
11902 {
11903 	/*
11904 	 * "adv" is the amount we could increase the window, taking into
11905 	 * account that we are limited by TCP_MAXWIN << tp->rcv_scale.
11906 	 */
11907 	int32_t adv;
11908 	int32_t oldwin;
11909 
11910 	adv = recwin;
11911 	if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt)) {
11912 		oldwin = (tp->rcv_adv - tp->rcv_nxt);
11913 		if (adv > oldwin)
11914 			adv -= oldwin;
11915 		else {
11916 			/* We can't increase the window */
11917 			adv = 0;
11918 		}
11919 	} else
11920 		oldwin = 0;
11921 
11922 	/*
11923 	 * If the new window size ends up being the same as or less
11924 	 * than the old size when it is scaled, then don't force
11925 	 * a window update.
11926 	 */
11927 	if (oldwin >> tp->rcv_scale >= (adv + oldwin) >> tp->rcv_scale)
11928 		return (0);
11929 
11930 	if (adv >= (2 * maxseg) &&
11931 	    (adv >= (so->so_rcv.sb_hiwat / 4) ||
11932 	    recwin <= (so->so_rcv.sb_hiwat / 8) ||
11933 	    so->so_rcv.sb_hiwat <= 8 * maxseg)) {
11934 		return (1);
11935 	}
11936 	if (2 * adv >= (int32_t) so->so_rcv.sb_hiwat)
11937 		return (1);
11938 	return (0);
11939 }
11940 
11941 /*
11942  * Return 0 on success and a errno on failure to send.
11943  * Note that a 0 return may not mean we sent anything
11944  * if the TCB was on the hpts. A non-zero return
11945  * does indicate the error we got from ip[6]_output.
11946  */
11947 static int
11948 bbr_output_wtime(struct tcpcb *tp, const struct timeval *tv)
11949 {
11950 	struct socket *so;
11951 	int32_t len;
11952 	uint32_t cts;
11953 	uint32_t recwin, sendwin;
11954 	int32_t sb_offset;
11955 	int32_t flags, abandon, error = 0;
11956 	struct tcp_log_buffer *lgb = NULL;
11957 	struct mbuf *m;
11958 	struct mbuf *mb;
11959 	uint32_t if_hw_tsomaxsegcount = 0;
11960 	uint32_t if_hw_tsomaxsegsize = 0;
11961 	uint32_t if_hw_tsomax = 0;
11962 	struct ip *ip = NULL;
11963 #ifdef TCPDEBUG
11964 	struct ipovly *ipov = NULL;
11965 #endif
11966 	struct tcp_bbr *bbr;
11967 	struct tcphdr *th;
11968 #ifdef NETFLIX_TCPOUDP
11969 	struct udphdr *udp = NULL;
11970 #endif
11971 	u_char opt[TCP_MAXOLEN];
11972 	unsigned ipoptlen, optlen, hdrlen;
11973 #ifdef NETFLIX_TCPOUDP
11974 	unsigned ulen;
11975 #endif
11976 	uint32_t bbr_seq;
11977 	uint32_t delay_calc=0;
11978 	uint8_t doing_tlp = 0;
11979 	uint8_t local_options;
11980 #ifdef BBR_INVARIANTS
11981 	uint8_t doing_retran_from = 0;
11982 	uint8_t picked_up_retran = 0;
11983 #endif
11984 	uint8_t wanted_cookie = 0;
11985 	uint8_t more_to_rxt=0;
11986 	int32_t prefetch_so_done = 0;
11987 	int32_t prefetch_rsm = 0;
11988  	uint32_t what_we_can = 0;
11989 	uint32_t tot_len = 0;
11990 	uint32_t rtr_cnt = 0;
11991 	uint32_t maxseg, pace_max_segs, p_maxseg;
11992 	int32_t csum_flags;
11993  	int32_t hw_tls;
11994 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
11995 	unsigned ipsec_optlen = 0;
11996 
11997 #endif
11998 	volatile int32_t sack_rxmit;
11999 	struct bbr_sendmap *rsm = NULL;
12000 	int32_t tso, mtu;
12001 	struct tcpopt to;
12002 	int32_t slot = 0;
12003 	struct inpcb *inp;
12004 	struct sockbuf *sb;
12005 	uint32_t hpts_calling;
12006 #ifdef INET6
12007 	struct ip6_hdr *ip6 = NULL;
12008 	int32_t isipv6;
12009 #endif
12010 	uint8_t app_limited = BBR_JR_SENT_DATA;
12011 	uint8_t filled_all = 0;
12012 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
12013 	/* We take a cache hit here */
12014 	memcpy(&bbr->rc_tv, tv, sizeof(struct timeval));
12015 	cts = tcp_tv_to_usectick(&bbr->rc_tv);
12016 	inp = bbr->rc_inp;
12017 	so = inp->inp_socket;
12018 	sb = &so->so_snd;
12019  	if (sb->sb_flags & SB_TLS_IFNET)
12020  		hw_tls = 1;
12021  	else
12022  		hw_tls = 0;
12023 	kern_prefetch(sb, &maxseg);
12024 	maxseg = tp->t_maxseg - bbr->rc_last_options;
12025 	if (bbr_minseg(bbr) < maxseg) {
12026 		tcp_bbr_tso_size_check(bbr, cts);
12027 	}
12028 	/* Remove any flags that indicate we are pacing on the inp  */
12029 	pace_max_segs = bbr->r_ctl.rc_pace_max_segs;
12030 	p_maxseg = min(maxseg, pace_max_segs);
12031 	INP_WLOCK_ASSERT(inp);
12032 #ifdef TCP_OFFLOAD
12033 	if (tp->t_flags & TF_TOE)
12034 		return (tcp_offload_output(tp));
12035 #endif
12036 
12037 #ifdef INET6
12038 	if (bbr->r_state) {
12039 		/* Use the cache line loaded if possible */
12040 		isipv6 = bbr->r_is_v6;
12041 	} else {
12042 		isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
12043 	}
12044 #endif
12045 	if (((bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) == 0) &&
12046 	    inp->inp_in_hpts) {
12047 		/*
12048 		 * We are on the hpts for some timer but not hptsi output.
12049 		 * Possibly remove from the hpts so we can send/recv etc.
12050 		 */
12051 		if ((tp->t_flags & TF_ACKNOW) == 0) {
12052 			/*
12053 			 * No immediate demand right now to send an ack, but
12054 			 * the user may have read, making room for new data
12055 			 * (a window update). If so we may want to cancel
12056 			 * whatever timer is running (KEEP/DEL-ACK?) and
12057 			 * continue to send out a window update. Or we may
12058 			 * have gotten more data into the socket buffer to
12059 			 * send.
12060 			 */
12061 			recwin = lmin(lmax(sbspace(&so->so_rcv), 0),
12062 				      (long)TCP_MAXWIN << tp->rcv_scale);
12063 			if ((bbr_window_update_needed(tp, so, recwin, maxseg) == 0) &&
12064 			    ((tcp_outflags[tp->t_state] & TH_RST) == 0) &&
12065 			    ((sbavail(sb) + ((tcp_outflags[tp->t_state] & TH_FIN) ? 1 : 0)) <=
12066 			    (tp->snd_max - tp->snd_una))) {
12067 				/*
12068 				 * Nothing new to send and no window update
12069 				 * is needed to send. Lets just return and
12070 				 * let the timer-run off.
12071 				 */
12072 				return (0);
12073 			}
12074 		}
12075 		tcp_hpts_remove(inp, HPTS_REMOVE_OUTPUT);
12076 		bbr_timer_cancel(bbr, __LINE__, cts);
12077 	}
12078 	if (bbr->r_ctl.rc_last_delay_val) {
12079 		/* Calculate a rough delay for early escape to sending  */
12080 		if (SEQ_GT(cts, bbr->rc_pacer_started))
12081 			delay_calc = cts - bbr->rc_pacer_started;
12082 		if (delay_calc >= bbr->r_ctl.rc_last_delay_val)
12083 			delay_calc -= bbr->r_ctl.rc_last_delay_val;
12084 		else
12085 			delay_calc = 0;
12086 	}
12087 	/* Mark that we have called bbr_output(). */
12088 	if ((bbr->r_timer_override) ||
12089 	    (tp->t_state < TCPS_ESTABLISHED)) {
12090 		/* Timeouts or early states are exempt */
12091 		if (inp->inp_in_hpts)
12092 			tcp_hpts_remove(inp, HPTS_REMOVE_OUTPUT);
12093 	} else if (inp->inp_in_hpts) {
12094 		if ((bbr->r_ctl.rc_last_delay_val) &&
12095 		    (bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT) &&
12096 		    delay_calc) {
12097 			/*
12098 			 * We were being paced for output and the delay has
12099 			 * already exceeded when we were supposed to be
12100 			 * called, lets go ahead and pull out of the hpts
12101 			 * and call output.
12102 			 */
12103 			counter_u64_add(bbr_out_size[TCP_MSS_ACCT_LATE], 1);
12104 			bbr->r_ctl.rc_last_delay_val = 0;
12105 			tcp_hpts_remove(inp, HPTS_REMOVE_OUTPUT);
12106 		} else if (tp->t_state == TCPS_CLOSED) {
12107 			bbr->r_ctl.rc_last_delay_val = 0;
12108 			tcp_hpts_remove(inp, HPTS_REMOVE_OUTPUT);
12109 		} else {
12110 			/*
12111 			 * On the hpts, you shall not pass! even if ACKNOW
12112 			 * is on, we will when the hpts fires, unless of
12113 			 * course we are overdue.
12114 			 */
12115 			counter_u64_add(bbr_out_size[TCP_MSS_ACCT_INPACE], 1);
12116 			return (0);
12117 		}
12118 	}
12119 	bbr->rc_cwnd_limited = 0;
12120 	if (bbr->r_ctl.rc_last_delay_val) {
12121 		/* recalculate the real delay and deal with over/under  */
12122 		if (SEQ_GT(cts, bbr->rc_pacer_started))
12123 			delay_calc = cts - bbr->rc_pacer_started;
12124 		else
12125 			delay_calc = 0;
12126 		if (delay_calc >= bbr->r_ctl.rc_last_delay_val)
12127 			/* Setup the delay which will be added in */
12128 			delay_calc -= bbr->r_ctl.rc_last_delay_val;
12129 		else {
12130 			/*
12131 			 * We are early setup to adjust
12132 			 * our slot time.
12133 			 */
12134 			uint64_t merged_val;
12135 
12136 			bbr->r_ctl.rc_agg_early += (bbr->r_ctl.rc_last_delay_val - delay_calc);
12137 			bbr->r_agg_early_set = 1;
12138 			if (bbr->r_ctl.rc_hptsi_agg_delay) {
12139 				if (bbr->r_ctl.rc_hptsi_agg_delay >= bbr->r_ctl.rc_agg_early) {
12140 					/* Nope our previous late cancels out the early */
12141 					bbr->r_ctl.rc_hptsi_agg_delay -= bbr->r_ctl.rc_agg_early;
12142 					bbr->r_agg_early_set = 0;
12143 					bbr->r_ctl.rc_agg_early = 0;
12144 				} else {
12145 					bbr->r_ctl.rc_agg_early -= bbr->r_ctl.rc_hptsi_agg_delay;
12146 					bbr->r_ctl.rc_hptsi_agg_delay = 0;
12147 				}
12148 			}
12149 			merged_val = bbr->rc_pacer_started;
12150 			merged_val <<= 32;
12151 			merged_val |= bbr->r_ctl.rc_last_delay_val;
12152 			bbr_log_pacing_delay_calc(bbr, inp->inp_hpts_calls,
12153 						 bbr->r_ctl.rc_agg_early, cts, delay_calc, merged_val,
12154 						 bbr->r_agg_early_set, 3);
12155 			bbr->r_ctl.rc_last_delay_val = 0;
12156 			BBR_STAT_INC(bbr_early);
12157 			delay_calc = 0;
12158 		}
12159 	} else {
12160 		/* We were not delayed due to hptsi */
12161 		if (bbr->r_agg_early_set)
12162 			bbr->r_ctl.rc_agg_early = 0;
12163 		bbr->r_agg_early_set = 0;
12164 		delay_calc = 0;
12165 	}
12166 	if (delay_calc) {
12167 		/*
12168 		 * We had a hptsi delay which means we are falling behind on
12169 		 * sending at the expected rate. Calculate an extra amount
12170 		 * of data we can send, if any, to put us back on track.
12171 		 */
12172 		if ((bbr->r_ctl.rc_hptsi_agg_delay + delay_calc) < bbr->r_ctl.rc_hptsi_agg_delay)
12173 			bbr->r_ctl.rc_hptsi_agg_delay = 0xffffffff;
12174 		else
12175 			bbr->r_ctl.rc_hptsi_agg_delay += delay_calc;
12176 	}
12177 	sendwin = min(tp->snd_wnd, tp->snd_cwnd);
12178 	if ((tp->snd_una == tp->snd_max) &&
12179 	    (bbr->rc_bbr_state != BBR_STATE_IDLE_EXIT) &&
12180 	    (sbavail(sb))) {
12181 		/*
12182 		 * Ok we have been idle with nothing outstanding
12183 		 * we possibly need to start fresh with either a new
12184 		 * suite of states or a fast-ramp up.
12185 		 */
12186 		bbr_restart_after_idle(bbr,
12187 				       cts, bbr_calc_time(cts, bbr->r_ctl.rc_went_idle_time));
12188 	}
12189 	/*
12190 	 * Now was there a hptsi delay where we are behind? We only count
12191 	 * being behind if: a) We are not in recovery. b) There was a delay.
12192 	 * <and> c) We had room to send something.
12193 	 *
12194 	 */
12195 	hpts_calling = inp->inp_hpts_calls;
12196 	inp->inp_hpts_calls = 0;
12197 	if (bbr->r_ctl.rc_hpts_flags & PACE_TMR_MASK) {
12198 		if (bbr_process_timers(tp, bbr, cts, hpts_calling)) {
12199 			counter_u64_add(bbr_out_size[TCP_MSS_ACCT_ATIMER], 1);
12200 			return (0);
12201 		}
12202 	}
12203 	bbr->rc_inp->inp_flags2 &= ~INP_MBUF_QUEUE_READY;
12204 	if (hpts_calling &&
12205 	    (bbr->r_ctl.rc_hpts_flags & PACE_PKT_OUTPUT)) {
12206 		bbr->r_ctl.rc_last_delay_val = 0;
12207 	}
12208 	bbr->r_timer_override = 0;
12209 	bbr->r_wanted_output = 0;
12210 	/*
12211 	 * For TFO connections in SYN_RECEIVED, only allow the initial
12212 	 * SYN|ACK and those sent by the retransmit timer.
12213 	 */
12214 	if (IS_FASTOPEN(tp->t_flags) &&
12215 	    ((tp->t_state == TCPS_SYN_RECEIVED) ||
12216 	     (tp->t_state == TCPS_SYN_SENT)) &&
12217 	    SEQ_GT(tp->snd_max, tp->snd_una) &&	/* initial SYN or SYN|ACK sent */
12218 	    (tp->t_rxtshift == 0)) {	/* not a retransmit */
12219 		len = 0;
12220 		goto just_return_nolock;
12221 	}
12222 	/*
12223 	 * Before sending anything check for a state update. For hpts
12224 	 * calling without input this is important. If its input calling
12225 	 * then this was already done.
12226 	 */
12227 	if (bbr->rc_use_google == 0)
12228 		bbr_check_bbr_for_state(bbr, cts, __LINE__, 0);
12229 again:
12230 	/*
12231 	 * If we've recently taken a timeout, snd_max will be greater than
12232 	 * snd_max. BBR in general does not pay much attention to snd_nxt
12233 	 * for historic reasons the persist timer still uses it. This means
12234 	 * we have to look at it. All retransmissions that are not persits
12235 	 * use the rsm that needs to be sent so snd_nxt is ignored. At the
12236 	 * end of this routine we pull snd_nxt always up to snd_max.
12237 	 */
12238 	doing_tlp = 0;
12239 #ifdef BBR_INVARIANTS
12240 	doing_retran_from = picked_up_retran = 0;
12241 #endif
12242 	error = 0;
12243 	tso = 0;
12244 	slot = 0;
12245 	mtu = 0;
12246 	sendwin = min(tp->snd_wnd, tp->snd_cwnd);
12247 	sb_offset = tp->snd_max - tp->snd_una;
12248 	flags = tcp_outflags[tp->t_state];
12249 	sack_rxmit = 0;
12250 	len = 0;
12251 	rsm = NULL;
12252 	if (flags & TH_RST) {
12253 		SOCKBUF_LOCK(sb);
12254 		goto send;
12255 	}
12256 recheck_resend:
12257 	while (bbr->r_ctl.rc_free_cnt < bbr_min_req_free) {
12258 		/* We need to always have one in reserve */
12259 		rsm = bbr_alloc(bbr);
12260 		if (rsm == NULL) {
12261 			error = ENOMEM;
12262 			/* Lie to get on the hpts */
12263 			tot_len = tp->t_maxseg;
12264 			if (hpts_calling)
12265 				/* Retry in a ms */
12266 				slot = 1001;
12267 			goto just_return_nolock;
12268 		}
12269 		TAILQ_INSERT_TAIL(&bbr->r_ctl.rc_free, rsm, r_next);
12270 		bbr->r_ctl.rc_free_cnt++;
12271 		rsm = NULL;
12272 	}
12273 	/* What do we send, a resend? */
12274 	if (bbr->r_ctl.rc_resend == NULL) {
12275 		/* Check for rack timeout */
12276 		bbr->r_ctl.rc_resend = bbr_check_recovery_mode(tp, bbr, cts);
12277 		if (bbr->r_ctl.rc_resend) {
12278 #ifdef BBR_INVARIANTS
12279 			picked_up_retran = 1;
12280 #endif
12281 			bbr_cong_signal(tp, NULL, CC_NDUPACK, bbr->r_ctl.rc_resend);
12282 		}
12283 	}
12284 	if (bbr->r_ctl.rc_resend) {
12285 		rsm = bbr->r_ctl.rc_resend;
12286 #ifdef BBR_INVARIANTS
12287 		doing_retran_from = 1;
12288 #endif
12289 		/* Remove any TLP flags its a RACK or T-O */
12290 		rsm->r_flags &= ~BBR_TLP;
12291 		bbr->r_ctl.rc_resend = NULL;
12292 		if (SEQ_LT(rsm->r_start, tp->snd_una)) {
12293 #ifdef BBR_INVARIANTS
12294 			panic("Huh, tp:%p bbr:%p rsm:%p start:%u < snd_una:%u\n",
12295 			    tp, bbr, rsm, rsm->r_start, tp->snd_una);
12296 			goto recheck_resend;
12297 #else
12298 			/* TSNH */
12299 			rsm = NULL;
12300 			goto recheck_resend;
12301 #endif
12302 		}
12303 		rtr_cnt++;
12304 		if (rsm->r_flags & BBR_HAS_SYN) {
12305 			/* Only retransmit a SYN by itself */
12306 			len = 0;
12307 			if ((flags & TH_SYN) == 0) {
12308 				/* Huh something is wrong */
12309 				rsm->r_start++;
12310 				if (rsm->r_start == rsm->r_end) {
12311 					/* Clean it up, somehow we missed the ack? */
12312 					bbr_log_syn(tp, NULL);
12313 				} else {
12314 					/* TFO with data? */
12315 					rsm->r_flags &= ~BBR_HAS_SYN;
12316 					len = rsm->r_end - rsm->r_start;
12317 				}
12318 			} else {
12319 				/* Retransmitting SYN */
12320 				rsm = NULL;
12321 				SOCKBUF_LOCK(sb);
12322 				goto send;
12323 			}
12324 		} else
12325 			len = rsm->r_end - rsm->r_start;
12326 		if ((bbr->rc_resends_use_tso == 0) &&
12327 		    (len > maxseg)) {
12328 			len = maxseg;
12329 			more_to_rxt = 1;
12330 		}
12331 		sb_offset = rsm->r_start - tp->snd_una;
12332 		if (len > 0) {
12333 			sack_rxmit = 1;
12334 			KMOD_TCPSTAT_INC(tcps_sack_rexmits);
12335 			KMOD_TCPSTAT_ADD(tcps_sack_rexmit_bytes,
12336 			    min(len, maxseg));
12337 		} else {
12338 			/* I dont think this can happen */
12339 			rsm = NULL;
12340 			goto recheck_resend;
12341 		}
12342 		BBR_STAT_INC(bbr_resends_set);
12343 	} else if (bbr->r_ctl.rc_tlp_send) {
12344 		/*
12345 		 * Tail loss probe
12346 		 */
12347 		doing_tlp = 1;
12348 		rsm = bbr->r_ctl.rc_tlp_send;
12349 		bbr->r_ctl.rc_tlp_send = NULL;
12350 		sack_rxmit = 1;
12351 		len = rsm->r_end - rsm->r_start;
12352 		rtr_cnt++;
12353 		if ((bbr->rc_resends_use_tso == 0) && (len > maxseg))
12354 			len = maxseg;
12355 
12356 		if (SEQ_GT(tp->snd_una, rsm->r_start)) {
12357 #ifdef BBR_INVARIANTS
12358 			panic("tp:%p bbc:%p snd_una:%u rsm:%p r_start:%u",
12359 			    tp, bbr, tp->snd_una, rsm, rsm->r_start);
12360 #else
12361 			/* TSNH */
12362 			rsm = NULL;
12363 			goto recheck_resend;
12364 #endif
12365 		}
12366 		sb_offset = rsm->r_start - tp->snd_una;
12367 		BBR_STAT_INC(bbr_tlp_set);
12368 	}
12369 	/*
12370 	 * Enforce a connection sendmap count limit if set
12371 	 * as long as we are not retransmiting.
12372 	 */
12373 	if ((rsm == NULL) &&
12374 	    (V_tcp_map_entries_limit > 0) &&
12375 	    (bbr->r_ctl.rc_num_maps_alloced >= V_tcp_map_entries_limit)) {
12376 		BBR_STAT_INC(bbr_alloc_limited);
12377 		if (!bbr->alloc_limit_reported) {
12378 			bbr->alloc_limit_reported = 1;
12379 			BBR_STAT_INC(bbr_alloc_limited_conns);
12380 		}
12381 		goto just_return_nolock;
12382 	}
12383 #ifdef BBR_INVARIANTS
12384 	if (rsm && SEQ_LT(rsm->r_start, tp->snd_una)) {
12385 		panic("tp:%p bbr:%p rsm:%p sb_offset:%u len:%u",
12386 		    tp, bbr, rsm, sb_offset, len);
12387 	}
12388 #endif
12389 	/*
12390 	 * Get standard flags, and add SYN or FIN if requested by 'hidden'
12391 	 * state flags.
12392 	 */
12393 	if (tp->t_flags & TF_NEEDFIN && (rsm == NULL))
12394 		flags |= TH_FIN;
12395 	if (tp->t_flags & TF_NEEDSYN)
12396 		flags |= TH_SYN;
12397 
12398 	if (rsm && (rsm->r_flags & BBR_HAS_FIN)) {
12399 		/* we are retransmitting the fin */
12400 		len--;
12401 		if (len) {
12402 			/*
12403 			 * When retransmitting data do *not* include the
12404 			 * FIN. This could happen from a TLP probe if we
12405 			 * allowed data with a FIN.
12406 			 */
12407 			flags &= ~TH_FIN;
12408 		}
12409 	} else if (rsm) {
12410 		if (flags & TH_FIN)
12411 			flags &= ~TH_FIN;
12412 	}
12413 	if ((sack_rxmit == 0) && (prefetch_rsm == 0)) {
12414 		void *end_rsm;
12415 
12416 		end_rsm = TAILQ_LAST_FAST(&bbr->r_ctl.rc_tmap, bbr_sendmap, r_tnext);
12417 		if (end_rsm)
12418 			kern_prefetch(end_rsm, &prefetch_rsm);
12419 		prefetch_rsm = 1;
12420 	}
12421 	SOCKBUF_LOCK(sb);
12422 	/*
12423 	 * If snd_nxt == snd_max and we have transmitted a FIN, the
12424 	 * sb_offset will be > 0 even if so_snd.sb_cc is 0, resulting in a
12425 	 * negative length.  This can also occur when TCP opens up its
12426 	 * congestion window while receiving additional duplicate acks after
12427 	 * fast-retransmit because TCP will reset snd_nxt to snd_max after
12428 	 * the fast-retransmit.
12429 	 *
12430 	 * In the normal retransmit-FIN-only case, however, snd_nxt will be
12431 	 * set to snd_una, the sb_offset will be 0, and the length may wind
12432 	 * up 0.
12433 	 *
12434 	 * If sack_rxmit is true we are retransmitting from the scoreboard
12435 	 * in which case len is already set.
12436 	 */
12437 	if (sack_rxmit == 0) {
12438 		uint32_t avail;
12439 
12440 		avail = sbavail(sb);
12441 		if (SEQ_GT(tp->snd_max, tp->snd_una))
12442 			sb_offset = tp->snd_max - tp->snd_una;
12443 		else
12444 			sb_offset = 0;
12445 		if (bbr->rc_tlp_new_data) {
12446 			/* TLP is forcing out new data */
12447 			uint32_t tlplen;
12448 
12449 			doing_tlp = 1;
12450 			tlplen = maxseg;
12451 
12452 			if (tlplen > (uint32_t)(avail - sb_offset)) {
12453 				tlplen = (uint32_t)(avail - sb_offset);
12454 			}
12455 			if (tlplen > tp->snd_wnd) {
12456 				len = tp->snd_wnd;
12457 			} else {
12458 				len = tlplen;
12459 			}
12460 			bbr->rc_tlp_new_data = 0;
12461 		} else {
12462 			what_we_can = len = bbr_what_can_we_send(tp, bbr, sendwin, avail, sb_offset, cts);
12463 			if ((len < p_maxseg) &&
12464 			    (bbr->rc_in_persist == 0) &&
12465 			    (ctf_outstanding(tp) >= (2 * p_maxseg)) &&
12466 			    ((avail - sb_offset) >= p_maxseg)) {
12467 				/*
12468 				 * We are not completing whats in the socket
12469 				 * buffer (i.e. there is at least a segment
12470 				 * waiting to send) and we have 2 or more
12471 				 * segments outstanding. There is no sense
12472 				 * of sending a little piece. Lets defer and
12473 				 * and wait until we can send a whole
12474 				 * segment.
12475 				 */
12476 				len = 0;
12477 			}
12478 			if (bbr->rc_in_persist) {
12479 				/*
12480 				 * We are in persists, figure out if
12481 				 * a retransmit is available (maybe the previous
12482 				 * persists we sent) or if we have to send new
12483 				 * data.
12484 				 */
12485 				rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
12486 				if (rsm) {
12487 					len = rsm->r_end - rsm->r_start;
12488 					if (rsm->r_flags & BBR_HAS_FIN)
12489 						len--;
12490 					if ((bbr->rc_resends_use_tso == 0) && (len > maxseg))
12491 						len = maxseg;
12492 					if (len > 1)
12493 						BBR_STAT_INC(bbr_persist_reneg);
12494 					/*
12495 					 * XXXrrs we could force the len to
12496 					 * 1 byte here to cause the chunk to
12497 					 * split apart.. but that would then
12498 					 * mean we always retransmit it as
12499 					 * one byte even after the window
12500 					 * opens.
12501 					 */
12502 					sack_rxmit = 1;
12503 					sb_offset = rsm->r_start - tp->snd_una;
12504 				} else {
12505 					/*
12506 					 * First time through in persists or peer
12507 					 * acked our one byte. Though we do have
12508 					 * to have something in the sb.
12509 					 */
12510 					len = 1;
12511 					sb_offset = 0;
12512 					if (avail == 0)
12513 					    len = 0;
12514 				}
12515 			}
12516 		}
12517 	}
12518 	if (prefetch_so_done == 0) {
12519 		kern_prefetch(so, &prefetch_so_done);
12520 		prefetch_so_done = 1;
12521 	}
12522 	/*
12523 	 * Lop off SYN bit if it has already been sent.  However, if this is
12524 	 * SYN-SENT state and if segment contains data and if we don't know
12525 	 * that foreign host supports TAO, suppress sending segment.
12526 	 */
12527 	if ((flags & TH_SYN) && (rsm == NULL) &&
12528 	    SEQ_GT(tp->snd_max, tp->snd_una)) {
12529 		if (tp->t_state != TCPS_SYN_RECEIVED)
12530 			flags &= ~TH_SYN;
12531 		/*
12532 		 * When sending additional segments following a TFO SYN|ACK,
12533 		 * do not include the SYN bit.
12534 		 */
12535 		if (IS_FASTOPEN(tp->t_flags) &&
12536 		    (tp->t_state == TCPS_SYN_RECEIVED))
12537 			flags &= ~TH_SYN;
12538 		sb_offset--, len++;
12539 		if (sbavail(sb) == 0)
12540 			len = 0;
12541 	} else if ((flags & TH_SYN) && rsm) {
12542 		/*
12543 		 * Subtract one from the len for the SYN being
12544 		 * retransmitted.
12545 		 */
12546 		len--;
12547 	}
12548 	/*
12549 	 * Be careful not to send data and/or FIN on SYN segments. This
12550 	 * measure is needed to prevent interoperability problems with not
12551 	 * fully conformant TCP implementations.
12552 	 */
12553 	if ((flags & TH_SYN) && (tp->t_flags & TF_NOOPT)) {
12554 		len = 0;
12555 		flags &= ~TH_FIN;
12556 	}
12557 	/*
12558 	 * On TFO sockets, ensure no data is sent in the following cases:
12559 	 *
12560 	 *  - When retransmitting SYN|ACK on a passively-created socket
12561 	 *  - When retransmitting SYN on an actively created socket
12562 	 *  - When sending a zero-length cookie (cookie request) on an
12563 	 *    actively created socket
12564 	 *  - When the socket is in the CLOSED state (RST is being sent)
12565 	 */
12566 	if (IS_FASTOPEN(tp->t_flags) &&
12567 	    (((flags & TH_SYN) && (tp->t_rxtshift > 0)) ||
12568 	     ((tp->t_state == TCPS_SYN_SENT) &&
12569 	      (tp->t_tfo_client_cookie_len == 0)) ||
12570 	     (flags & TH_RST))) {
12571 		len = 0;
12572 		sack_rxmit = 0;
12573 		rsm = NULL;
12574 	}
12575 	/* Without fast-open there should never be data sent on a SYN */
12576 	if ((flags & TH_SYN) && (!IS_FASTOPEN(tp->t_flags)))
12577 		len = 0;
12578 	if (len <= 0) {
12579 		/*
12580 		 * If FIN has been sent but not acked, but we haven't been
12581 		 * called to retransmit, len will be < 0.  Otherwise, window
12582 		 * shrank after we sent into it.  If window shrank to 0,
12583 		 * cancel pending retransmit, pull snd_nxt back to (closed)
12584 		 * window, and set the persist timer if it isn't already
12585 		 * going.  If the window didn't close completely, just wait
12586 		 * for an ACK.
12587 		 *
12588 		 * We also do a general check here to ensure that we will
12589 		 * set the persist timer when we have data to send, but a
12590 		 * 0-byte window. This makes sure the persist timer is set
12591 		 * even if the packet hits one of the "goto send" lines
12592 		 * below.
12593 		 */
12594 		len = 0;
12595 		if ((tp->snd_wnd == 0) &&
12596 		    (TCPS_HAVEESTABLISHED(tp->t_state)) &&
12597 		    (tp->snd_una == tp->snd_max) &&
12598 		    (sb_offset < (int)sbavail(sb))) {
12599 			/*
12600 			 * Not enough room in the rwnd to send
12601 			 * a paced segment out.
12602 			 */
12603 			bbr_enter_persist(tp, bbr, cts, __LINE__);
12604 		}
12605 	} else if ((rsm == NULL) &&
12606 		   (doing_tlp == 0) &&
12607 		   (len < bbr->r_ctl.rc_pace_max_segs)) {
12608 		/*
12609 		 * We are not sending a full segment for
12610 		 * some reason. Should we not send anything (think
12611 		 * sws or persists)?
12612 		 */
12613 		if ((tp->snd_wnd < min((bbr->r_ctl.rc_high_rwnd/2), bbr_minseg(bbr))) &&
12614 		    (TCPS_HAVEESTABLISHED(tp->t_state)) &&
12615 		    (len < (int)(sbavail(sb) - sb_offset))) {
12616 			/*
12617 			 * Here the rwnd is less than
12618 			 * the pacing size, this is not a retransmit,
12619 			 * we are established and
12620 			 * the send is not the last in the socket buffer
12621 			 * lets not send, and possibly enter persists.
12622 			 */
12623 			len = 0;
12624 			if (tp->snd_max == tp->snd_una)
12625 				bbr_enter_persist(tp, bbr, cts, __LINE__);
12626 		} else if ((tp->snd_cwnd >= bbr->r_ctl.rc_pace_max_segs) &&
12627 			   (ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
12628 						 bbr->r_ctl.rc_lost_bytes)) > (2 * maxseg)) &&
12629 			   (len < (int)(sbavail(sb) - sb_offset)) &&
12630 			   (len < bbr_minseg(bbr))) {
12631 			/*
12632 			 * Here we are not retransmitting, and
12633 			 * the cwnd is not so small that we could
12634 			 * not send at least a min size (rxt timer
12635 			 * not having gone off), We have 2 segments or
12636 			 * more already in flight, its not the tail end
12637 			 * of the socket buffer  and the cwnd is blocking
12638 			 * us from sending out minimum pacing segment size.
12639 			 * Lets not send anything.
12640 			 */
12641 			bbr->rc_cwnd_limited = 1;
12642 			len = 0;
12643 		} else if (((tp->snd_wnd - ctf_outstanding(tp)) <
12644 			    min((bbr->r_ctl.rc_high_rwnd/2), bbr_minseg(bbr))) &&
12645 			   (ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
12646 						 bbr->r_ctl.rc_lost_bytes)) > (2 * maxseg)) &&
12647 			   (len < (int)(sbavail(sb) - sb_offset)) &&
12648 			   (TCPS_HAVEESTABLISHED(tp->t_state))) {
12649 			/*
12650 			 * Here we have a send window but we have
12651 			 * filled it up and we can't send another pacing segment.
12652 			 * We also have in flight more than 2 segments
12653 			 * and we are not completing the sb i.e. we allow
12654 			 * the last bytes of the sb to go out even if
12655 			 * its not a full pacing segment.
12656 			 */
12657 			len = 0;
12658 		}
12659 	}
12660 	/* len will be >= 0 after this point. */
12661 	KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__));
12662 	tcp_sndbuf_autoscale(tp, so, sendwin);
12663 	/*
12664 	 *
12665 	 */
12666 	if (bbr->rc_in_persist &&
12667 	    len &&
12668 	    (rsm == NULL) &&
12669 	    (len < min((bbr->r_ctl.rc_high_rwnd/2), bbr->r_ctl.rc_pace_max_segs))) {
12670 		/*
12671 		 * We are in persist, not doing a retransmit and don't have enough space
12672 		 * yet to send a full TSO. So is it at the end of the sb
12673 		 * if so we need to send else nuke to 0 and don't send.
12674 		 */
12675 		int sbleft;
12676 		if (sbavail(sb) > sb_offset)
12677 			sbleft = sbavail(sb) - sb_offset;
12678 		else
12679 			sbleft = 0;
12680 		if (sbleft >= min((bbr->r_ctl.rc_high_rwnd/2), bbr->r_ctl.rc_pace_max_segs)) {
12681 			/* not at end of sb lets not send */
12682 			len = 0;
12683 		}
12684 	}
12685 	/*
12686 	 * Decide if we can use TCP Segmentation Offloading (if supported by
12687 	 * hardware).
12688 	 *
12689 	 * TSO may only be used if we are in a pure bulk sending state.  The
12690 	 * presence of TCP-MD5, SACK retransmits, SACK advertizements and IP
12691 	 * options prevent using TSO.  With TSO the TCP header is the same
12692 	 * (except for the sequence number) for all generated packets.  This
12693 	 * makes it impossible to transmit any options which vary per
12694 	 * generated segment or packet.
12695 	 *
12696 	 * IPv4 handling has a clear separation of ip options and ip header
12697 	 * flags while IPv6 combines both in in6p_outputopts. ip6_optlen()
12698 	 * does the right thing below to provide length of just ip options
12699 	 * and thus checking for ipoptlen is enough to decide if ip options
12700 	 * are present.
12701 	 */
12702 #ifdef INET6
12703 	if (isipv6)
12704 		ipoptlen = ip6_optlen(inp);
12705 	else
12706 #endif
12707 	if (inp->inp_options)
12708 		ipoptlen = inp->inp_options->m_len -
12709 		    offsetof(struct ipoption, ipopt_list);
12710 	else
12711 		ipoptlen = 0;
12712 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
12713 	/*
12714 	 * Pre-calculate here as we save another lookup into the darknesses
12715 	 * of IPsec that way and can actually decide if TSO is ok.
12716 	 */
12717 #ifdef INET6
12718 	if (isipv6 && IPSEC_ENABLED(ipv6))
12719 		ipsec_optlen = IPSEC_HDRSIZE(ipv6, inp);
12720 #ifdef INET
12721 	else
12722 #endif
12723 #endif				/* INET6 */
12724 #ifdef INET
12725 	if (IPSEC_ENABLED(ipv4))
12726 		ipsec_optlen = IPSEC_HDRSIZE(ipv4, inp);
12727 #endif				/* INET */
12728 #endif				/* IPSEC */
12729 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
12730 	ipoptlen += ipsec_optlen;
12731 #endif
12732 	if ((tp->t_flags & TF_TSO) && V_tcp_do_tso &&
12733 	    (len > maxseg) &&
12734 	    (tp->t_port == 0) &&
12735 	    ((tp->t_flags & TF_SIGNATURE) == 0) &&
12736 	    tp->rcv_numsacks == 0 &&
12737 	    ipoptlen == 0)
12738 		tso = 1;
12739 
12740 	recwin = lmin(lmax(sbspace(&so->so_rcv), 0),
12741 	    (long)TCP_MAXWIN << tp->rcv_scale);
12742 	/*
12743 	 * Sender silly window avoidance.   We transmit under the following
12744 	 * conditions when len is non-zero:
12745 	 *
12746 	 * - We have a full segment (or more with TSO) - This is the last
12747 	 * buffer in a write()/send() and we are either idle or running
12748 	 * NODELAY - we've timed out (e.g. persist timer) - we have more
12749 	 * then 1/2 the maximum send window's worth of data (receiver may be
12750 	 * limited the window size) - we need to retransmit
12751 	 */
12752 	if (rsm)
12753 		goto send;
12754 	if (len) {
12755 		if (sack_rxmit)
12756 			goto send;
12757 		if (len >= p_maxseg)
12758 			goto send;
12759 		/*
12760 		 * NOTE! on localhost connections an 'ack' from the remote
12761 		 * end may occur synchronously with the output and cause us
12762 		 * to flush a buffer queued with moretocome.  XXX
12763 		 *
12764 		 */
12765 		if (((tp->t_flags & TF_MORETOCOME) == 0) &&	/* normal case */
12766 		    ((tp->t_flags & TF_NODELAY) ||
12767 		    ((uint32_t)len + (uint32_t)sb_offset) >= sbavail(&so->so_snd)) &&
12768 		    (tp->t_flags & TF_NOPUSH) == 0) {
12769 			goto send;
12770 		}
12771 		if ((tp->snd_una == tp->snd_max) && len) {	/* Nothing outstanding */
12772 			goto send;
12773 		}
12774 		if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) {
12775 			goto send;
12776 		}
12777 	}
12778 	/*
12779 	 * Sending of standalone window updates.
12780 	 *
12781 	 * Window updates are important when we close our window due to a
12782 	 * full socket buffer and are opening it again after the application
12783 	 * reads data from it.  Once the window has opened again and the
12784 	 * remote end starts to send again the ACK clock takes over and
12785 	 * provides the most current window information.
12786 	 *
12787 	 * We must avoid the silly window syndrome whereas every read from
12788 	 * the receive buffer, no matter how small, causes a window update
12789 	 * to be sent.  We also should avoid sending a flurry of window
12790 	 * updates when the socket buffer had queued a lot of data and the
12791 	 * application is doing small reads.
12792 	 *
12793 	 * Prevent a flurry of pointless window updates by only sending an
12794 	 * update when we can increase the advertized window by more than
12795 	 * 1/4th of the socket buffer capacity.  When the buffer is getting
12796 	 * full or is very small be more aggressive and send an update
12797 	 * whenever we can increase by two mss sized segments. In all other
12798 	 * situations the ACK's to new incoming data will carry further
12799 	 * window increases.
12800 	 *
12801 	 * Don't send an independent window update if a delayed ACK is
12802 	 * pending (it will get piggy-backed on it) or the remote side
12803 	 * already has done a half-close and won't send more data.  Skip
12804 	 * this if the connection is in T/TCP half-open state.
12805 	 */
12806 	if (recwin > 0 && !(tp->t_flags & TF_NEEDSYN) &&
12807 	    !(tp->t_flags & TF_DELACK) &&
12808 	    !TCPS_HAVERCVDFIN(tp->t_state)) {
12809 		/* Check to see if we should do a window update */
12810 		if (bbr_window_update_needed(tp, so, recwin, maxseg))
12811 			goto send;
12812 	}
12813 	/*
12814 	 * Send if we owe the peer an ACK, RST, SYN.  ACKNOW
12815 	 * is also a catch-all for the retransmit timer timeout case.
12816 	 */
12817 	if (tp->t_flags & TF_ACKNOW) {
12818 		goto send;
12819 	}
12820 	if (flags & TH_RST) {
12821 		/* Always send a RST if one is due */
12822 		goto send;
12823 	}
12824 	if ((flags & TH_SYN) && (tp->t_flags & TF_NEEDSYN) == 0) {
12825 		goto send;
12826 	}
12827 	/*
12828 	 * If our state indicates that FIN should be sent and we have not
12829 	 * yet done so, then we need to send.
12830 	 */
12831 	if (flags & TH_FIN &&
12832 	    ((tp->t_flags & TF_SENTFIN) == 0)) {
12833 		goto send;
12834 	}
12835 	/*
12836 	 * No reason to send a segment, just return.
12837 	 */
12838 just_return:
12839 	SOCKBUF_UNLOCK(sb);
12840 just_return_nolock:
12841 	if (tot_len)
12842 		slot = bbr_get_pacing_delay(bbr, bbr->r_ctl.rc_bbr_hptsi_gain, tot_len, cts, 0);
12843 	if (bbr->rc_no_pacing)
12844 		slot = 0;
12845 	if (tot_len == 0) {
12846 		if ((ctf_outstanding(tp) + min((bbr->r_ctl.rc_high_rwnd/2), bbr_minseg(bbr))) >=
12847 		    tp->snd_wnd) {
12848 			BBR_STAT_INC(bbr_rwnd_limited);
12849 			app_limited = BBR_JR_RWND_LIMITED;
12850 			bbr_cwnd_limiting(tp, bbr, ctf_outstanding(tp));
12851 			if ((bbr->rc_in_persist == 0) &&
12852 			    TCPS_HAVEESTABLISHED(tp->t_state) &&
12853 			    (tp->snd_max == tp->snd_una) &&
12854 			    sbavail(&tp->t_inpcb->inp_socket->so_snd)) {
12855 				/* No send window.. we must enter persist */
12856 				bbr_enter_persist(tp, bbr, bbr->r_ctl.rc_rcvtime, __LINE__);
12857 			}
12858 		} else if (ctf_outstanding(tp) >= sbavail(sb)) {
12859 			BBR_STAT_INC(bbr_app_limited);
12860 			app_limited = BBR_JR_APP_LIMITED;
12861 			bbr_cwnd_limiting(tp, bbr, ctf_outstanding(tp));
12862 		} else if ((ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
12863 						 bbr->r_ctl.rc_lost_bytes)) + p_maxseg) >= tp->snd_cwnd) {
12864 			BBR_STAT_INC(bbr_cwnd_limited);
12865  			app_limited = BBR_JR_CWND_LIMITED;
12866 			bbr_cwnd_limiting(tp, bbr, ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
12867 									bbr->r_ctl.rc_lost_bytes)));
12868 			bbr->rc_cwnd_limited = 1;
12869 		} else {
12870 			BBR_STAT_INC(bbr_app_limited);
12871 			app_limited = BBR_JR_APP_LIMITED;
12872 			bbr_cwnd_limiting(tp, bbr, ctf_outstanding(tp));
12873 		}
12874 		bbr->r_ctl.rc_hptsi_agg_delay = 0;
12875 		bbr->r_agg_early_set = 0;
12876 		bbr->r_ctl.rc_agg_early = 0;
12877 		bbr->r_ctl.rc_last_delay_val = 0;
12878 	} else if (bbr->rc_use_google == 0)
12879 		bbr_check_bbr_for_state(bbr, cts, __LINE__, 0);
12880 	/* Are we app limited? */
12881 	if ((app_limited == BBR_JR_APP_LIMITED) ||
12882 	    (app_limited == BBR_JR_RWND_LIMITED)) {
12883 		/**
12884 		 * We are application limited.
12885 		 */
12886 		bbr->r_ctl.r_app_limited_until = (ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
12887 								       bbr->r_ctl.rc_lost_bytes)) + bbr->r_ctl.rc_delivered);
12888 	}
12889 	if (tot_len == 0)
12890 		counter_u64_add(bbr_out_size[TCP_MSS_ACCT_JUSTRET], 1);
12891 	/* Dont update the time if we did not send */
12892 	bbr->r_ctl.rc_last_delay_val = 0;
12893 	bbr->rc_output_starts_timer = 1;
12894 	bbr_start_hpts_timer(bbr, tp, cts, 9, slot, tot_len);
12895 	bbr_log_type_just_return(bbr, cts, tot_len, hpts_calling, app_limited, p_maxseg, len);
12896 	if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
12897 		/* Make sure snd_nxt is drug up */
12898 		tp->snd_nxt = tp->snd_max;
12899 	}
12900 	return (error);
12901 
12902 send:
12903 	if (doing_tlp == 0) {
12904 		/*
12905 		 * Data not a TLP, and its not the rxt firing. If it is the
12906 		 * rxt firing, we want to leave the tlp_in_progress flag on
12907 		 * so we don't send another TLP. It has to be a rack timer
12908 		 * or normal send (response to acked data) to clear the tlp
12909 		 * in progress flag.
12910 		 */
12911 		bbr->rc_tlp_in_progress = 0;
12912 		bbr->rc_tlp_rtx_out = 0;
12913 	} else {
12914 		/*
12915 		 * Its a TLP.
12916 		 */
12917 		bbr->rc_tlp_in_progress = 1;
12918 	}
12919 	bbr_timer_cancel(bbr, __LINE__, cts);
12920 	if (rsm == NULL) {
12921 		if (sbused(sb) > 0) {
12922 			/*
12923 			 * This is sub-optimal. We only send a stand alone
12924 			 * FIN on its own segment.
12925 			 */
12926 			if (flags & TH_FIN) {
12927 				flags &= ~TH_FIN;
12928 				if ((len == 0) && ((tp->t_flags & TF_ACKNOW) == 0)) {
12929 					/* Lets not send this */
12930 					slot = 0;
12931 					goto just_return;
12932 				}
12933 			}
12934 		}
12935 	} else {
12936 		/*
12937 		 * We do *not* send a FIN on a retransmit if it has data.
12938 		 * The if clause here where len > 1 should never come true.
12939 		 */
12940 		if ((len > 0) &&
12941 		    (((rsm->r_flags & BBR_HAS_FIN) == 0) &&
12942 		    (flags & TH_FIN))) {
12943 			flags &= ~TH_FIN;
12944 			len--;
12945 		}
12946 	}
12947 	SOCKBUF_LOCK_ASSERT(sb);
12948 	if (len > 0) {
12949 		if ((tp->snd_una == tp->snd_max) &&
12950 		    (bbr_calc_time(cts, bbr->r_ctl.rc_went_idle_time) >= bbr_rtt_probe_time)) {
12951 			/*
12952 			 * This qualifies as a RTT_PROBE session since we
12953 			 * drop the data outstanding to nothing and waited
12954 			 * more than bbr_rtt_probe_time.
12955 			 */
12956 			bbr_log_rtt_shrinks(bbr, cts, 0, 0, __LINE__, BBR_RTTS_WASIDLE, 0);
12957 			bbr_set_reduced_rtt(bbr, cts, __LINE__);
12958 		}
12959 		if (len >= maxseg)
12960 			tp->t_flags2 |= TF2_PLPMTU_MAXSEGSNT;
12961 		else
12962 			tp->t_flags2 &= ~TF2_PLPMTU_MAXSEGSNT;
12963 	}
12964 	/*
12965 	 * Before ESTABLISHED, force sending of initial options unless TCP
12966 	 * set not to do any options. NOTE: we assume that the IP/TCP header
12967 	 * plus TCP options always fit in a single mbuf, leaving room for a
12968 	 * maximum link header, i.e. max_linkhdr + sizeof (struct tcpiphdr)
12969 	 * + optlen <= MCLBYTES
12970 	 */
12971 	optlen = 0;
12972 #ifdef INET6
12973 	if (isipv6)
12974 		hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
12975 	else
12976 #endif
12977 		hdrlen = sizeof(struct tcpiphdr);
12978 
12979 	/*
12980 	 * Compute options for segment. We only have to care about SYN and
12981 	 * established connection segments.  Options for SYN-ACK segments
12982 	 * are handled in TCP syncache.
12983 	 */
12984 	to.to_flags = 0;
12985 	local_options = 0;
12986 	if ((tp->t_flags & TF_NOOPT) == 0) {
12987 		/* Maximum segment size. */
12988 		if (flags & TH_SYN) {
12989 			to.to_mss = tcp_mssopt(&inp->inp_inc);
12990 #ifdef NETFLIX_TCPOUDP
12991 			if (tp->t_port)
12992 				to.to_mss -= V_tcp_udp_tunneling_overhead;
12993 #endif
12994 			to.to_flags |= TOF_MSS;
12995 			/*
12996 			 * On SYN or SYN|ACK transmits on TFO connections,
12997 			 * only include the TFO option if it is not a
12998 			 * retransmit, as the presence of the TFO option may
12999 			 * have caused the original SYN or SYN|ACK to have
13000 			 * been dropped by a middlebox.
13001 			 */
13002 			if (IS_FASTOPEN(tp->t_flags) &&
13003 			    (tp->t_rxtshift == 0)) {
13004 				if (tp->t_state == TCPS_SYN_RECEIVED) {
13005 					to.to_tfo_len = TCP_FASTOPEN_COOKIE_LEN;
13006 					to.to_tfo_cookie =
13007 					    (u_int8_t *)&tp->t_tfo_cookie.server;
13008 					to.to_flags |= TOF_FASTOPEN;
13009 					wanted_cookie = 1;
13010 				} else if (tp->t_state == TCPS_SYN_SENT) {
13011 					to.to_tfo_len =
13012 					    tp->t_tfo_client_cookie_len;
13013 					to.to_tfo_cookie =
13014 					    tp->t_tfo_cookie.client;
13015 					to.to_flags |= TOF_FASTOPEN;
13016 					wanted_cookie = 1;
13017 				}
13018 			}
13019 		}
13020 		/* Window scaling. */
13021 		if ((flags & TH_SYN) && (tp->t_flags & TF_REQ_SCALE)) {
13022 			to.to_wscale = tp->request_r_scale;
13023 			to.to_flags |= TOF_SCALE;
13024 		}
13025 		/* Timestamps. */
13026 		if ((tp->t_flags & TF_RCVD_TSTMP) ||
13027 		    ((flags & TH_SYN) && (tp->t_flags & TF_REQ_TSTMP))) {
13028 			to.to_tsval = 	tcp_tv_to_mssectick(&bbr->rc_tv) + tp->ts_offset;
13029 			to.to_tsecr = tp->ts_recent;
13030 			to.to_flags |= TOF_TS;
13031 			local_options += TCPOLEN_TIMESTAMP + 2;
13032 		}
13033 		/* Set receive buffer autosizing timestamp. */
13034 		if (tp->rfbuf_ts == 0 &&
13035 		    (so->so_rcv.sb_flags & SB_AUTOSIZE))
13036 			tp->rfbuf_ts = 	tcp_tv_to_mssectick(&bbr->rc_tv);
13037 		/* Selective ACK's. */
13038 		if (flags & TH_SYN)
13039 			to.to_flags |= TOF_SACKPERM;
13040 		else if (TCPS_HAVEESTABLISHED(tp->t_state) &&
13041 		    tp->rcv_numsacks > 0) {
13042 			to.to_flags |= TOF_SACK;
13043 			to.to_nsacks = tp->rcv_numsacks;
13044 			to.to_sacks = (u_char *)tp->sackblks;
13045 		}
13046 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
13047 		/* TCP-MD5 (RFC2385). */
13048 		if (tp->t_flags & TF_SIGNATURE)
13049 			to.to_flags |= TOF_SIGNATURE;
13050 #endif				/* TCP_SIGNATURE */
13051 
13052 		/* Processing the options. */
13053 		hdrlen += (optlen = tcp_addoptions(&to, opt));
13054 		/*
13055 		 * If we wanted a TFO option to be added, but it was unable
13056 		 * to fit, ensure no data is sent.
13057 		 */
13058 		if (IS_FASTOPEN(tp->t_flags) && wanted_cookie &&
13059 		    !(to.to_flags & TOF_FASTOPEN))
13060 			len = 0;
13061 	}
13062 #ifdef NETFLIX_TCPOUDP
13063 	if (tp->t_port) {
13064 		if (V_tcp_udp_tunneling_port == 0) {
13065 			/* The port was removed?? */
13066 			SOCKBUF_UNLOCK(&so->so_snd);
13067 			return (EHOSTUNREACH);
13068 		}
13069 		hdrlen += sizeof(struct udphdr);
13070 	}
13071 #endif
13072 #ifdef INET6
13073 	if (isipv6)
13074 		ipoptlen = ip6_optlen(tp->t_inpcb);
13075 	else
13076 #endif
13077 	if (tp->t_inpcb->inp_options)
13078 		ipoptlen = tp->t_inpcb->inp_options->m_len -
13079 		    offsetof(struct ipoption, ipopt_list);
13080 	else
13081 		ipoptlen = 0;
13082 	ipoptlen = 0;
13083 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
13084 	ipoptlen += ipsec_optlen;
13085 #endif
13086 	if (bbr->rc_last_options != local_options) {
13087 		/*
13088 		 * Cache the options length this generally does not change
13089 		 * on a connection. We use this to calculate TSO.
13090 		 */
13091 		bbr->rc_last_options = local_options;
13092 	}
13093 	maxseg = tp->t_maxseg - (ipoptlen + optlen);
13094 	p_maxseg = min(maxseg, pace_max_segs);
13095 	/*
13096 	 * Adjust data length if insertion of options will bump the packet
13097 	 * length beyond the t_maxseg length. Clear the FIN bit because we
13098 	 * cut off the tail of the segment.
13099 	 */
13100 	if (len > maxseg) {
13101 		if (len != 0 && (flags & TH_FIN)) {
13102 			flags &= ~TH_FIN;
13103 		}
13104 		if (tso) {
13105 			uint32_t moff;
13106 			int32_t max_len;
13107 
13108 			/* extract TSO information */
13109 			if_hw_tsomax = tp->t_tsomax;
13110 			if_hw_tsomaxsegcount = tp->t_tsomaxsegcount;
13111 			if_hw_tsomaxsegsize = tp->t_tsomaxsegsize;
13112 			KASSERT(ipoptlen == 0,
13113 			    ("%s: TSO can't do IP options", __func__));
13114 
13115 			/*
13116 			 * Check if we should limit by maximum payload
13117 			 * length:
13118 			 */
13119 			if (if_hw_tsomax != 0) {
13120 				/* compute maximum TSO length */
13121 				max_len = (if_hw_tsomax - hdrlen -
13122 				    max_linkhdr);
13123 				if (max_len <= 0) {
13124 					len = 0;
13125 				} else if (len > max_len) {
13126 					len = max_len;
13127 				}
13128 			}
13129 			/*
13130 			 * Prevent the last segment from being fractional
13131 			 * unless the send sockbuf can be emptied:
13132 			 */
13133 			if ((sb_offset + len) < sbavail(sb)) {
13134 				moff = len % (uint32_t)maxseg;
13135 				if (moff != 0) {
13136 					len -= moff;
13137 				}
13138 			}
13139 			/*
13140 			 * In case there are too many small fragments don't
13141 			 * use TSO:
13142 			 */
13143 			if (len <= maxseg) {
13144 				len = maxseg;
13145 				tso = 0;
13146 			}
13147 		} else {
13148 			/* Not doing TSO */
13149 			if (optlen + ipoptlen >= tp->t_maxseg) {
13150 				/*
13151 				 * Since we don't have enough space to put
13152 				 * the IP header chain and the TCP header in
13153 				 * one packet as required by RFC 7112, don't
13154 				 * send it. Also ensure that at least one
13155 				 * byte of the payload can be put into the
13156 				 * TCP segment.
13157 				 */
13158 				SOCKBUF_UNLOCK(&so->so_snd);
13159 				error = EMSGSIZE;
13160 				sack_rxmit = 0;
13161 				goto out;
13162 			}
13163 			len = maxseg;
13164 		}
13165 	} else {
13166 		/* Not doing TSO */
13167 		if_hw_tsomaxsegcount = 0;
13168 		tso = 0;
13169 	}
13170 	KASSERT(len + hdrlen + ipoptlen <= IP_MAXPACKET,
13171 	    ("%s: len > IP_MAXPACKET", __func__));
13172 #ifdef DIAGNOSTIC
13173 #ifdef INET6
13174 	if (max_linkhdr + hdrlen > MCLBYTES)
13175 #else
13176 	if (max_linkhdr + hdrlen > MHLEN)
13177 #endif
13178 		panic("tcphdr too big");
13179 #endif
13180 	/*
13181 	 * This KASSERT is here to catch edge cases at a well defined place.
13182 	 * Before, those had triggered (random) panic conditions further
13183 	 * down.
13184 	 */
13185 #ifdef BBR_INVARIANTS
13186 	if (sack_rxmit) {
13187 		if (SEQ_LT(rsm->r_start, tp->snd_una)) {
13188 			panic("RSM:%p TP:%p bbr:%p start:%u is < snd_una:%u",
13189 			    rsm, tp, bbr, rsm->r_start, tp->snd_una);
13190 		}
13191 	}
13192 #endif
13193 	KASSERT(len >= 0, ("[%s:%d]: len < 0", __func__, __LINE__));
13194 	if ((len == 0) &&
13195 	    (flags & TH_FIN) &&
13196 	    (sbused(sb))) {
13197 		/*
13198 		 * We have outstanding data, don't send a fin by itself!.
13199 		 */
13200 		slot = 0;
13201 		goto just_return;
13202 	}
13203 	/*
13204 	 * Grab a header mbuf, attaching a copy of data to be transmitted,
13205 	 * and initialize the header from the template for sends on this
13206 	 * connection.
13207 	 */
13208 	if (len) {
13209 		uint32_t moff;
13210 		uint32_t orig_len;
13211 
13212 		/*
13213 		 * We place a limit on sending with hptsi.
13214 		 */
13215 		if ((rsm == NULL) && len > pace_max_segs)
13216 			len = pace_max_segs;
13217 		if (len <= maxseg)
13218 			tso = 0;
13219 #ifdef INET6
13220 		if (MHLEN < hdrlen + max_linkhdr)
13221 			m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
13222 		else
13223 #endif
13224 			m = m_gethdr(M_NOWAIT, MT_DATA);
13225 
13226 		if (m == NULL) {
13227 			BBR_STAT_INC(bbr_failed_mbuf_aloc);
13228 			bbr_log_enobuf_jmp(bbr, len, cts, __LINE__, len, 0, 0);
13229 			SOCKBUF_UNLOCK(sb);
13230 			error = ENOBUFS;
13231 			sack_rxmit = 0;
13232 			goto out;
13233 		}
13234 		m->m_data += max_linkhdr;
13235 		m->m_len = hdrlen;
13236 		/*
13237 		 * Start the m_copy functions from the closest mbuf to the
13238 		 * sb_offset in the socket buffer chain.
13239 		 */
13240 		if ((sb_offset > sbavail(sb)) || ((len + sb_offset) > sbavail(sb))) {
13241 #ifdef BBR_INVARIANTS
13242 			if ((len + sb_offset) > (sbavail(sb) + ((flags & (TH_FIN | TH_SYN)) ? 1 : 0)))
13243 				panic("tp:%p bbr:%p len:%u sb_offset:%u sbavail:%u rsm:%p %u:%u:%u",
13244 				    tp, bbr, len, sb_offset, sbavail(sb), rsm,
13245 				    doing_retran_from,
13246 				    picked_up_retran,
13247 				    doing_tlp);
13248 
13249 #endif
13250 			/*
13251 			 * In this messed up situation we have two choices,
13252 			 * a) pretend the send worked, and just start timers
13253 			 * and what not (not good since that may lead us
13254 			 * back here a lot). <or> b) Send the lowest segment
13255 			 * in the map. <or> c) Drop the connection. Lets do
13256 			 * <b> which if it continues to happen will lead to
13257 			 * <c> via timeouts.
13258 			 */
13259 			BBR_STAT_INC(bbr_offset_recovery);
13260 			rsm = TAILQ_FIRST(&bbr->r_ctl.rc_map);
13261 			sb_offset = 0;
13262 			if (rsm == NULL) {
13263 				sack_rxmit = 0;
13264 				len = sbavail(sb);
13265 			} else {
13266 				sack_rxmit = 1;
13267 				if (rsm->r_start != tp->snd_una) {
13268 					/*
13269 					 * Things are really messed up, <c>
13270 					 * is the only thing to do.
13271 					 */
13272 					BBR_STAT_INC(bbr_offset_drop);
13273 					tcp_set_inp_to_drop(inp, EFAULT);
13274 					SOCKBUF_UNLOCK(sb);
13275 					(void)m_free(m);
13276 					return (0);
13277 				}
13278 				len = rsm->r_end - rsm->r_start;
13279 			}
13280 			if (len > sbavail(sb))
13281 				len = sbavail(sb);
13282 			if (len > maxseg)
13283 				len = maxseg;
13284 		}
13285 		mb = sbsndptr_noadv(sb, sb_offset, &moff);
13286 		if (len <= MHLEN - hdrlen - max_linkhdr && !hw_tls) {
13287 			m_copydata(mb, moff, (int)len,
13288 			    mtod(m, caddr_t)+hdrlen);
13289 			if (rsm == NULL)
13290 				sbsndptr_adv(sb, mb, len);
13291 			m->m_len += len;
13292 		} else {
13293 			struct sockbuf *msb;
13294 
13295 			if (rsm)
13296 				msb = NULL;
13297 			else
13298 				msb = sb;
13299 #ifdef BBR_INVARIANTS
13300 			if ((len + moff) > (sbavail(sb) + ((flags & (TH_FIN | TH_SYN)) ? 1 : 0))) {
13301 				if (rsm) {
13302 					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 ",
13303 					    tp, bbr, len, moff,
13304 					    sbavail(sb), rsm,
13305 					    tp->snd_una, rsm->r_flags, rsm->r_start,
13306 					    doing_retran_from,
13307 					    picked_up_retran,
13308 					    doing_tlp, sack_rxmit);
13309 				} else {
13310 					panic("tp:%p bbr:%p len:%u moff:%u sbavail:%u sb_offset:%u snd_una:%u",
13311 					    tp, bbr, len, moff, sbavail(sb), sb_offset, tp->snd_una);
13312 				}
13313 			}
13314 #endif
13315 			orig_len = len;
13316 			m->m_next = tcp_m_copym(
13317 				mb, moff, &len,
13318 				if_hw_tsomaxsegcount,
13319 				if_hw_tsomaxsegsize, msb,
13320 				((rsm == NULL) ? hw_tls : 0)
13321 #ifdef NETFLIX_COPY_ARGS
13322 				, &filled_all
13323 #endif
13324 				);
13325 			if (len <= maxseg) {
13326 				/*
13327 				 * Must have ran out of mbufs for the copy
13328 				 * shorten it to no longer need tso. Lets
13329 				 * not put on sendalot since we are low on
13330 				 * mbufs.
13331 				 */
13332 				tso = 0;
13333 			}
13334 			if (m->m_next == NULL) {
13335 				SOCKBUF_UNLOCK(sb);
13336 				(void)m_free(m);
13337 				error = ENOBUFS;
13338 				sack_rxmit = 0;
13339 				goto out;
13340 			}
13341 		}
13342 #ifdef BBR_INVARIANTS
13343 		if (tso && len < maxseg) {
13344 			panic("tp:%p tso on, but len:%d < maxseg:%d",
13345 			    tp, len, maxseg);
13346 		}
13347 		if (tso && if_hw_tsomaxsegcount) {
13348 			int32_t seg_cnt = 0;
13349 			struct mbuf *foo;
13350 
13351 			foo = m;
13352 			while (foo) {
13353 				seg_cnt++;
13354 				foo = foo->m_next;
13355 			}
13356 			if (seg_cnt > if_hw_tsomaxsegcount) {
13357 				panic("seg_cnt:%d > max:%d", seg_cnt, if_hw_tsomaxsegcount);
13358 			}
13359 		}
13360 #endif
13361 		/*
13362 		 * If we're sending everything we've got, set PUSH. (This
13363 		 * will keep happy those implementations which only give
13364 		 * data to the user when a buffer fills or a PUSH comes in.)
13365 		 */
13366 		if (sb_offset + len == sbused(sb) &&
13367 		    sbused(sb) &&
13368 		    !(flags & TH_SYN)) {
13369 			flags |= TH_PUSH;
13370 		}
13371 		SOCKBUF_UNLOCK(sb);
13372 	} else {
13373 		SOCKBUF_UNLOCK(sb);
13374 		if (tp->t_flags & TF_ACKNOW)
13375 			KMOD_TCPSTAT_INC(tcps_sndacks);
13376 		else if (flags & (TH_SYN | TH_FIN | TH_RST))
13377 			KMOD_TCPSTAT_INC(tcps_sndctrl);
13378 		else
13379 			KMOD_TCPSTAT_INC(tcps_sndwinup);
13380 
13381 		m = m_gethdr(M_NOWAIT, MT_DATA);
13382 		if (m == NULL) {
13383 			BBR_STAT_INC(bbr_failed_mbuf_aloc);
13384 			bbr_log_enobuf_jmp(bbr, len, cts, __LINE__, len, 0, 0);
13385 			error = ENOBUFS;
13386 			/* Fudge the send time since we could not send */
13387 			sack_rxmit = 0;
13388 			goto out;
13389 		}
13390 #ifdef INET6
13391 		if (isipv6 && (MHLEN < hdrlen + max_linkhdr) &&
13392 		    MHLEN >= hdrlen) {
13393 			M_ALIGN(m, hdrlen);
13394 		} else
13395 #endif
13396 			m->m_data += max_linkhdr;
13397 		m->m_len = hdrlen;
13398 	}
13399 	SOCKBUF_UNLOCK_ASSERT(sb);
13400 	m->m_pkthdr.rcvif = (struct ifnet *)0;
13401 #ifdef MAC
13402 	mac_inpcb_create_mbuf(inp, m);
13403 #endif
13404 #ifdef INET6
13405 	if (isipv6) {
13406 		ip6 = mtod(m, struct ip6_hdr *);
13407 #ifdef NETFLIX_TCPOUDP
13408 		if (tp->t_port) {
13409 			udp = (struct udphdr *)((caddr_t)ip6 + ipoptlen + sizeof(struct ip6_hdr));
13410 			udp->uh_sport = htons(V_tcp_udp_tunneling_port);
13411 			udp->uh_dport = tp->t_port;
13412 			ulen = hdrlen + len - sizeof(struct ip6_hdr);
13413 			udp->uh_ulen = htons(ulen);
13414 			th = (struct tcphdr *)(udp + 1);
13415 		} else {
13416 #endif
13417 			th = (struct tcphdr *)(ip6 + 1);
13418 
13419 #ifdef NETFLIX_TCPOUDP
13420 		}
13421 #endif
13422 		tcpip_fillheaders(inp,
13423 #ifdef NETFLIX_TCPOUDP
13424 				  tp->t_port,
13425 #endif
13426 				  ip6, th);
13427 	} else
13428 #endif				/* INET6 */
13429 	{
13430 		ip = mtod(m, struct ip *);
13431 #ifdef TCPDEBUG
13432 		ipov = (struct ipovly *)ip;
13433 #endif
13434 #ifdef NETFLIX_TCPOUDP
13435 		if (tp->t_port) {
13436 			udp = (struct udphdr *)((caddr_t)ip + ipoptlen + sizeof(struct ip));
13437 			udp->uh_sport = htons(V_tcp_udp_tunneling_port);
13438 			udp->uh_dport = tp->t_port;
13439 			ulen = hdrlen + len - sizeof(struct ip);
13440 			udp->uh_ulen = htons(ulen);
13441 			th = (struct tcphdr *)(udp + 1);
13442 		} else
13443 #endif
13444 			th = (struct tcphdr *)(ip + 1);
13445 		tcpip_fillheaders(inp,
13446 #ifdef NETFLIX_TCPOUDP
13447 				  tp->t_port,
13448 #endif
13449 				  ip, th);
13450 	}
13451 	/*
13452 	 * If we are doing retransmissions, then snd_nxt will not reflect
13453 	 * the first unsent octet.  For ACK only packets, we do not want the
13454 	 * sequence number of the retransmitted packet, we want the sequence
13455 	 * number of the next unsent octet.  So, if there is no data (and no
13456 	 * SYN or FIN), use snd_max instead of snd_nxt when filling in
13457 	 * ti_seq.  But if we are in persist state, snd_max might reflect
13458 	 * one byte beyond the right edge of the window, so use snd_nxt in
13459 	 * that case, since we know we aren't doing a retransmission.
13460 	 * (retransmit and persist are mutually exclusive...)
13461 	 */
13462 	if (sack_rxmit == 0) {
13463 		if (len && ((flags & (TH_FIN | TH_SYN | TH_RST)) == 0)) {
13464 			/* New data (including new persists) */
13465 			th->th_seq = htonl(tp->snd_max);
13466 			bbr_seq = tp->snd_max;
13467 		} else if (flags & TH_SYN) {
13468 			/* Syn's always send from iss */
13469 			th->th_seq = htonl(tp->iss);
13470 			bbr_seq = tp->iss;
13471 		} else if (flags & TH_FIN) {
13472 			if (flags & TH_FIN && tp->t_flags & TF_SENTFIN) {
13473 				/*
13474 				 * If we sent the fin already its 1 minus
13475 				 * snd_max
13476 				 */
13477 				th->th_seq = (htonl(tp->snd_max - 1));
13478 				bbr_seq = (tp->snd_max - 1);
13479 			} else {
13480 				/* First time FIN use snd_max */
13481 				th->th_seq = htonl(tp->snd_max);
13482 				bbr_seq = tp->snd_max;
13483 			}
13484 		} else if (flags & TH_RST) {
13485 			/*
13486 			 * For a Reset send the last cum ack in sequence
13487 			 * (this like any other choice may still generate a
13488 			 * challenge ack, if a ack-update packet is in
13489 			 * flight).
13490 			 */
13491 			th->th_seq = htonl(tp->snd_una);
13492 			bbr_seq = tp->snd_una;
13493 		} else {
13494 			/*
13495 			 * len == 0 and not persist we use snd_max, sending
13496 			 * an ack unless we have sent the fin then its 1
13497 			 * minus.
13498 			 */
13499 			/*
13500 			 * XXXRRS Question if we are in persists and we have
13501 			 * nothing outstanding to send and we have not sent
13502 			 * a FIN, we will send an ACK. In such a case it
13503 			 * might be better to send (tp->snd_una - 1) which
13504 			 * would force the peer to ack.
13505 			 */
13506 			if (tp->t_flags & TF_SENTFIN) {
13507 				th->th_seq = htonl(tp->snd_max - 1);
13508 				bbr_seq = (tp->snd_max - 1);
13509 			} else {
13510 				th->th_seq = htonl(tp->snd_max);
13511 				bbr_seq = tp->snd_max;
13512 			}
13513 		}
13514 	} else {
13515 		/* All retransmits use the rsm to guide the send */
13516 		th->th_seq = htonl(rsm->r_start);
13517 		bbr_seq = rsm->r_start;
13518 	}
13519 	th->th_ack = htonl(tp->rcv_nxt);
13520 	if (optlen) {
13521 		bcopy(opt, th + 1, optlen);
13522 		th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
13523 	}
13524 	th->th_flags = flags;
13525 	/*
13526 	 * Calculate receive window.  Don't shrink window, but avoid silly
13527 	 * window syndrome.
13528 	 */
13529 	if ((flags & TH_RST) || ((recwin < (so->so_rcv.sb_hiwat / 4) &&
13530 				  recwin < maxseg)))
13531 		recwin = 0;
13532 	if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt) &&
13533 	    recwin < (tp->rcv_adv - tp->rcv_nxt))
13534 		recwin = (tp->rcv_adv - tp->rcv_nxt);
13535 	if (recwin > TCP_MAXWIN << tp->rcv_scale)
13536 		recwin = TCP_MAXWIN << tp->rcv_scale;
13537 
13538 	/*
13539 	 * According to RFC1323 the window field in a SYN (i.e., a <SYN> or
13540 	 * <SYN,ACK>) segment itself is never scaled.  The <SYN,ACK> case is
13541 	 * handled in syncache.
13542 	 */
13543 	if (flags & TH_SYN)
13544 		th->th_win = htons((u_short)
13545 		    (min(sbspace(&so->so_rcv), TCP_MAXWIN)));
13546 	else {
13547 		/* Avoid shrinking window with window scaling. */
13548 		recwin = roundup2(recwin, 1 << tp->rcv_scale);
13549 		th->th_win = htons((u_short)(recwin >> tp->rcv_scale));
13550 	}
13551 	/*
13552 	 * Adjust the RXWIN0SENT flag - indicate that we have advertised a 0
13553 	 * window.  This may cause the remote transmitter to stall.  This
13554 	 * flag tells soreceive() to disable delayed acknowledgements when
13555 	 * draining the buffer.  This can occur if the receiver is
13556 	 * attempting to read more data than can be buffered prior to
13557 	 * transmitting on the connection.
13558 	 */
13559 	if (th->th_win == 0) {
13560 		tp->t_sndzerowin++;
13561 		tp->t_flags |= TF_RXWIN0SENT;
13562 	} else
13563 		tp->t_flags &= ~TF_RXWIN0SENT;
13564 	/*
13565 	 * We don't support urgent data, but drag along
13566 	 * the pointer in case of a stack switch.
13567 	 */
13568 	tp->snd_up = tp->snd_una;
13569 
13570 #if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
13571 	if (to.to_flags & TOF_SIGNATURE) {
13572 		/*
13573 		 * Calculate MD5 signature and put it into the place
13574 		 * determined before. NOTE: since TCP options buffer doesn't
13575 		 * point into mbuf's data, calculate offset and use it.
13576 		 */
13577 		if (!TCPMD5_ENABLED() || TCPMD5_OUTPUT(m, th,
13578 		    (u_char *)(th + 1) + (to.to_signature - opt)) != 0) {
13579 			/*
13580 			 * Do not send segment if the calculation of MD5
13581 			 * digest has failed.
13582 			 */
13583 			goto out;
13584 		}
13585 	}
13586 #endif
13587 
13588 	/*
13589 	 * Put TCP length in extended header, and then checksum extended
13590 	 * header and data.
13591 	 */
13592 	m->m_pkthdr.len = hdrlen + len;	/* in6_cksum() need this */
13593 #ifdef INET6
13594 	if (isipv6) {
13595 		/*
13596 		 * ip6_plen is not need to be filled now, and will be filled
13597 		 * in ip6_output.
13598 		 */
13599 #ifdef NETFLIX_TCPOUDP
13600 		if (tp->t_port) {
13601 			m->m_pkthdr.csum_flags = CSUM_UDP_IPV6;
13602 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
13603 			udp->uh_sum = in6_cksum_pseudo(ip6, ulen, IPPROTO_UDP, 0);
13604 			th->th_sum = htons(0);
13605 			UDPSTAT_INC(udps_opackets);
13606 		} else {
13607 #endif
13608 			csum_flags = m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
13609 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
13610 			th->th_sum = in6_cksum_pseudo(ip6, sizeof(struct tcphdr) +
13611 			    optlen + len, IPPROTO_TCP, 0);
13612 #ifdef NETFLIX_TCPOUDP
13613 		}
13614 #endif
13615 	}
13616 #endif
13617 #if defined(INET6) && defined(INET)
13618 	else
13619 #endif
13620 #ifdef INET
13621 	{
13622 #ifdef NETFLIX_TCPOUDP
13623 		if (tp->t_port) {
13624 			m->m_pkthdr.csum_flags = CSUM_UDP;
13625 			m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
13626 			udp->uh_sum = in_pseudo(ip->ip_src.s_addr,
13627 			    ip->ip_dst.s_addr, htons(ulen + IPPROTO_UDP));
13628 			th->th_sum = htons(0);
13629 			UDPSTAT_INC(udps_opackets);
13630 		} else {
13631 #endif
13632 			csum_flags = m->m_pkthdr.csum_flags = CSUM_TCP;
13633 			m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
13634 			th->th_sum = in_pseudo(ip->ip_src.s_addr,
13635 			    ip->ip_dst.s_addr, htons(sizeof(struct tcphdr) +
13636 			    IPPROTO_TCP + len + optlen));
13637 #ifdef NETFLIX_TCPOUDP
13638 		}
13639 #endif
13640 		/* IP version must be set here for ipv4/ipv6 checking later */
13641 		KASSERT(ip->ip_v == IPVERSION,
13642 		    ("%s: IP version incorrect: %d", __func__, ip->ip_v));
13643 	}
13644 #endif
13645 
13646 	/*
13647 	 * Enable TSO and specify the size of the segments. The TCP pseudo
13648 	 * header checksum is always provided. XXX: Fixme: This is currently
13649 	 * not the case for IPv6.
13650 	 */
13651 	if (tso) {
13652 		KASSERT(len > maxseg,
13653 		    ("%s: len:%d <= tso_segsz:%d", __func__, len, maxseg));
13654 		m->m_pkthdr.csum_flags |= CSUM_TSO;
13655 		csum_flags |= CSUM_TSO;
13656 		m->m_pkthdr.tso_segsz = maxseg;
13657 	}
13658 	KASSERT(len + hdrlen == m_length(m, NULL),
13659 	    ("%s: mbuf chain different than expected: %d + %u != %u",
13660 	    __func__, len, hdrlen, m_length(m, NULL)));
13661 
13662 #ifdef TCP_HHOOK
13663 	/* Run HHOOK_TC_ESTABLISHED_OUT helper hooks. */
13664 	hhook_run_tcp_est_out(tp, th, &to, len, tso);
13665 #endif
13666 #ifdef TCPDEBUG
13667 	/*
13668 	 * Trace.
13669 	 */
13670 	if (so->so_options & SO_DEBUG) {
13671 		u_short save = 0;
13672 
13673 #ifdef INET6
13674 		if (!isipv6)
13675 #endif
13676 		{
13677 			save = ipov->ih_len;
13678 			ipov->ih_len = htons(m->m_pkthdr.len	/* - hdrlen +
13679 			      * (th->th_off << 2) */ );
13680 		}
13681 		tcp_trace(TA_OUTPUT, tp->t_state, tp, mtod(m, void *), th, 0);
13682 #ifdef INET6
13683 		if (!isipv6)
13684 #endif
13685 			ipov->ih_len = save;
13686 	}
13687 #endif				/* TCPDEBUG */
13688 
13689 	/* Log to the black box */
13690 	if (tp->t_logstate != TCP_LOG_STATE_OFF) {
13691 		union tcp_log_stackspecific log;
13692 
13693 		bbr_fill_in_logging_data(bbr, &log.u_bbr, cts);
13694 		/* Record info on type of transmission */
13695 		log.u_bbr.flex1 = bbr->r_ctl.rc_hptsi_agg_delay;
13696 		log.u_bbr.flex2 = (bbr->r_recovery_bw << 3);
13697 		log.u_bbr.flex3 = maxseg;
13698 		log.u_bbr.flex4 = delay_calc;
13699 		/* Encode filled_all into the upper flex5 bit */
13700 		log.u_bbr.flex5 = bbr->rc_past_init_win;
13701 		log.u_bbr.flex5 <<= 1;
13702 		log.u_bbr.flex5 |= bbr->rc_no_pacing;
13703 		log.u_bbr.flex5 <<= 29;
13704 		if (filled_all)
13705 			log.u_bbr.flex5 |= 0x80000000;
13706 		log.u_bbr.flex5 |= tp->t_maxseg;
13707 		log.u_bbr.flex6 = bbr->r_ctl.rc_pace_max_segs;
13708 		log.u_bbr.flex7 = (bbr->rc_bbr_state << 8) | bbr_state_val(bbr);
13709 		/* lets poke in the low and the high here for debugging */
13710 		log.u_bbr.pkts_out = bbr->rc_tp->t_maxseg;
13711 		if (rsm || sack_rxmit) {
13712 			if (doing_tlp)
13713 				log.u_bbr.flex8 = 2;
13714 			else
13715 				log.u_bbr.flex8 = 1;
13716 		} else {
13717 			log.u_bbr.flex8 = 0;
13718 		}
13719 		lgb = tcp_log_event_(tp, th, &so->so_rcv, &so->so_snd, TCP_LOG_OUT, ERRNO_UNK,
13720 		    len, &log, false, NULL, NULL, 0, tv);
13721 	} else {
13722 		lgb = NULL;
13723 	}
13724 	/*
13725 	 * Fill in IP length and desired time to live and send to IP level.
13726 	 * There should be a better way to handle ttl and tos; we could keep
13727 	 * them in the template, but need a way to checksum without them.
13728 	 */
13729 	/*
13730 	 * m->m_pkthdr.len should have been set before cksum calcuration,
13731 	 * because in6_cksum() need it.
13732 	 */
13733 #ifdef INET6
13734 	if (isipv6) {
13735 		/*
13736 		 * we separately set hoplimit for every segment, since the
13737 		 * user might want to change the value via setsockopt. Also,
13738 		 * desired default hop limit might be changed via Neighbor
13739 		 * Discovery.
13740 		 */
13741 		ip6->ip6_hlim = in6_selecthlim(inp, NULL);
13742 
13743 		/*
13744 		 * Set the packet size here for the benefit of DTrace
13745 		 * probes. ip6_output() will set it properly; it's supposed
13746 		 * to include the option header lengths as well.
13747 		 */
13748 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
13749 
13750 		if (V_path_mtu_discovery && maxseg > V_tcp_minmss)
13751 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
13752 		else
13753 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
13754 
13755 		if (tp->t_state == TCPS_SYN_SENT)
13756 			TCP_PROBE5(connect__request, NULL, tp, ip6, tp, th);
13757 
13758 		TCP_PROBE5(send, NULL, tp, ip6, tp, th);
13759 		/* TODO: IPv6 IP6TOS_ECT bit on */
13760 		error = ip6_output(m, inp->in6p_outputopts,
13761 		    &inp->inp_route6,
13762 		    ((rsm || sack_rxmit) ? IP_NO_SND_TAG_RL : 0),
13763 		    NULL, NULL, inp);
13764 
13765 		if (error == EMSGSIZE && inp->inp_route6.ro_nh != NULL)
13766 			mtu = inp->inp_route6.ro_nh->nh_mtu;
13767 	}
13768 #endif				/* INET6 */
13769 #if defined(INET) && defined(INET6)
13770 	else
13771 #endif
13772 #ifdef INET
13773 	{
13774 		ip->ip_len = htons(m->m_pkthdr.len);
13775 #ifdef INET6
13776 		if (isipv6)
13777 			ip->ip_ttl = in6_selecthlim(inp, NULL);
13778 #endif				/* INET6 */
13779 		/*
13780 		 * If we do path MTU discovery, then we set DF on every
13781 		 * packet. This might not be the best thing to do according
13782 		 * to RFC3390 Section 2. However the tcp hostcache migitates
13783 		 * the problem so it affects only the first tcp connection
13784 		 * with a host.
13785 		 *
13786 		 * NB: Don't set DF on small MTU/MSS to have a safe
13787 		 * fallback.
13788 		 */
13789 		if (V_path_mtu_discovery && tp->t_maxseg > V_tcp_minmss) {
13790 			tp->t_flags2 |= TF2_PLPMTU_PMTUD;
13791 			if (tp->t_port == 0 || len < V_tcp_minmss) {
13792 				ip->ip_off |= htons(IP_DF);
13793 			}
13794 		} else {
13795 			tp->t_flags2 &= ~TF2_PLPMTU_PMTUD;
13796 		}
13797 
13798 		if (tp->t_state == TCPS_SYN_SENT)
13799 			TCP_PROBE5(connect__request, NULL, tp, ip, tp, th);
13800 
13801 		TCP_PROBE5(send, NULL, tp, ip, tp, th);
13802 
13803 		error = ip_output(m, inp->inp_options, &inp->inp_route,
13804 		    ((rsm || sack_rxmit) ? IP_NO_SND_TAG_RL : 0), 0,
13805 		    inp);
13806 		if (error == EMSGSIZE && inp->inp_route.ro_nh != NULL)
13807 			mtu = inp->inp_route.ro_nh->nh_mtu;
13808 	}
13809 #endif				/* INET */
13810 out:
13811 
13812 	if (lgb) {
13813 		lgb->tlb_errno = error;
13814 		lgb = NULL;
13815 	}
13816 	/*
13817 	 * In transmit state, time the transmission and arrange for the
13818 	 * retransmit.  In persist state, just set snd_max.
13819 	 */
13820 	if (error == 0) {
13821 		if (TCPS_HAVEESTABLISHED(tp->t_state) &&
13822 		    (tp->t_flags & TF_SACK_PERMIT) &&
13823 		    tp->rcv_numsacks > 0)
13824 			tcp_clean_dsack_blocks(tp);
13825 		/* We sent an ack clear the bbr_segs_rcvd count */
13826 		bbr->output_error_seen = 0;
13827 		bbr->oerror_cnt = 0;
13828 		bbr->bbr_segs_rcvd = 0;
13829 		if (len == 0)
13830 			counter_u64_add(bbr_out_size[TCP_MSS_ACCT_SNDACK], 1);
13831 		/* Do accounting for new sends */
13832 		if ((len > 0) && (rsm == NULL)) {
13833 			int idx;
13834 			if (tp->snd_una == tp->snd_max) {
13835 				/*
13836 				 * Special case to match google, when
13837 				 * nothing is in flight the delivered
13838 				 * time does get updated to the current
13839 				 * time (see tcp_rate_bsd.c).
13840 				 */
13841 				bbr->r_ctl.rc_del_time = cts;
13842 			}
13843 			if (len >= maxseg) {
13844 				idx = (len / maxseg) + 3;
13845 				if (idx >= TCP_MSS_ACCT_ATIMER)
13846 					counter_u64_add(bbr_out_size[(TCP_MSS_ACCT_ATIMER - 1)], 1);
13847 				else
13848 					counter_u64_add(bbr_out_size[idx], 1);
13849 			} else {
13850 				/* smaller than a MSS */
13851 				idx = len / (bbr_hptsi_bytes_min - bbr->rc_last_options);
13852 				if (idx >= TCP_MSS_SMALL_MAX_SIZE_DIV)
13853 					idx = (TCP_MSS_SMALL_MAX_SIZE_DIV - 1);
13854 				counter_u64_add(bbr_out_size[(idx + TCP_MSS_SMALL_SIZE_OFF)], 1);
13855 			}
13856 		}
13857 	}
13858 	abandon = 0;
13859 	/*
13860 	 * We must do the send accounting before we log the output,
13861 	 * otherwise the state of the rsm could change and we account to the
13862 	 * wrong bucket.
13863 	 */
13864 	if (len > 0) {
13865 		bbr_do_send_accounting(tp, bbr, rsm, len, error);
13866 		if (error == 0) {
13867 			if (tp->snd_una == tp->snd_max)
13868 				bbr->r_ctl.rc_tlp_rxt_last_time = cts;
13869 		}
13870 	}
13871 	bbr_log_output(bbr, tp, &to, len, bbr_seq, (uint8_t) flags, error,
13872 	    cts, mb, &abandon, rsm, 0, sb);
13873 	if (abandon) {
13874 		/*
13875 		 * If bbr_log_output destroys the TCB or sees a TH_RST being
13876 		 * sent we should hit this condition.
13877 		 */
13878 		return (0);
13879 	}
13880 	if (bbr->rc_in_persist == 0) {
13881 		/*
13882 		 * Advance snd_nxt over sequence space of this segment.
13883 		 */
13884 		if (error)
13885 			/* We don't log or do anything with errors */
13886 			goto skip_upd;
13887 
13888 		if (tp->snd_una == tp->snd_max &&
13889 		    (len || (flags & (TH_SYN | TH_FIN)))) {
13890 			/*
13891 			 * Update the time we just added data since none was
13892 			 * outstanding.
13893 			 */
13894 			bbr_log_progress_event(bbr, tp, ticks, PROGRESS_START, __LINE__);
13895 			bbr->rc_tp->t_acktime  = ticks;
13896 		}
13897 		if (flags & (TH_SYN | TH_FIN) && (rsm == NULL)) {
13898 			if (flags & TH_SYN) {
13899 				/*
13900 				 * Smack the snd_max to iss + 1
13901 				 * if its a FO we will add len below.
13902 				 */
13903 				tp->snd_max = tp->iss + 1;
13904 			}
13905 			if ((flags & TH_FIN) && ((tp->t_flags & TF_SENTFIN) == 0)) {
13906 				tp->snd_max++;
13907 				tp->t_flags |= TF_SENTFIN;
13908 			}
13909 		}
13910 		if (sack_rxmit == 0)
13911 			tp->snd_max += len;
13912 skip_upd:
13913 		if ((error == 0) && len)
13914 			tot_len += len;
13915 	} else {
13916 		/* Persists case */
13917 		int32_t xlen = len;
13918 
13919 		if (error)
13920 			goto nomore;
13921 
13922 		if (flags & TH_SYN)
13923 			++xlen;
13924 		if ((flags & TH_FIN) && ((tp->t_flags & TF_SENTFIN) == 0)) {
13925 			++xlen;
13926 			tp->t_flags |= TF_SENTFIN;
13927 		}
13928 		if (xlen && (tp->snd_una == tp->snd_max)) {
13929 			/*
13930 			 * Update the time we just added data since none was
13931 			 * outstanding.
13932 			 */
13933 			bbr_log_progress_event(bbr, tp, ticks, PROGRESS_START, __LINE__);
13934 			bbr->rc_tp->t_acktime = ticks;
13935 		}
13936 		if (sack_rxmit == 0)
13937 			tp->snd_max += xlen;
13938 		tot_len += (len + optlen + ipoptlen);
13939 	}
13940 nomore:
13941 	if (error) {
13942 		/*
13943 		 * Failures do not advance the seq counter above. For the
13944 		 * case of ENOBUFS we will fall out and become ack-clocked.
13945 		 * capping the cwnd at the current flight.
13946 		 * Everything else will just have to retransmit with the timer
13947 		 * (no pacer).
13948 		 */
13949 		SOCKBUF_UNLOCK_ASSERT(sb);
13950 		BBR_STAT_INC(bbr_saw_oerr);
13951 		/* Clear all delay/early tracks */
13952 		bbr->r_ctl.rc_hptsi_agg_delay = 0;
13953 		bbr->r_ctl.rc_agg_early = 0;
13954 		bbr->r_agg_early_set = 0;
13955 		bbr->output_error_seen = 1;
13956 		if (bbr->oerror_cnt < 0xf)
13957 			bbr->oerror_cnt++;
13958 		if (bbr_max_net_error_cnt && (bbr->oerror_cnt >= bbr_max_net_error_cnt)) {
13959 			/* drop the session */
13960 			tcp_set_inp_to_drop(inp, ENETDOWN);
13961 		}
13962 		switch (error) {
13963 		case ENOBUFS:
13964 			/*
13965 			 * Make this guy have to get ack's to send
13966 			 * more but lets make sure we don't
13967 			 * slam him below a T-O (1MSS).
13968 			 */
13969 			if (bbr->rc_bbr_state != BBR_STATE_PROBE_RTT) {
13970 				tp->snd_cwnd = ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
13971 								    bbr->r_ctl.rc_lost_bytes)) - maxseg;
13972 				if (tp->snd_cwnd < maxseg)
13973 					tp->snd_cwnd = maxseg;
13974 			}
13975 			slot = (bbr_error_base_paceout + 1) << bbr->oerror_cnt;
13976 			BBR_STAT_INC(bbr_saw_enobuf);
13977 			if (bbr->bbr_hdrw_pacing)
13978 				counter_u64_add(bbr_hdwr_pacing_enobuf, 1);
13979 			else
13980 				counter_u64_add(bbr_nohdwr_pacing_enobuf, 1);
13981 			/*
13982 			 * Here even in the enobuf's case we want to do our
13983 			 * state update. The reason being we may have been
13984 			 * called by the input function. If so we have had
13985 			 * things change.
13986 			 */
13987 			error = 0;
13988 			goto enobufs;
13989 		case EMSGSIZE:
13990 			/*
13991 			 * For some reason the interface we used initially
13992 			 * to send segments changed to another or lowered
13993 			 * its MTU. If TSO was active we either got an
13994 			 * interface without TSO capabilits or TSO was
13995 			 * turned off. If we obtained mtu from ip_output()
13996 			 * then update it and try again.
13997 			 */
13998 			/* Turn on tracing (or try to) */
13999 			{
14000 				int old_maxseg;
14001 
14002 				old_maxseg = tp->t_maxseg;
14003 				BBR_STAT_INC(bbr_saw_emsgsiz);
14004 				bbr_log_msgsize_fail(bbr, tp, len, maxseg, mtu, csum_flags, tso, cts);
14005 				if (mtu != 0)
14006 					tcp_mss_update(tp, -1, mtu, NULL, NULL);
14007 				if (old_maxseg <= tp->t_maxseg) {
14008 					/* Huh it did not shrink? */
14009 					tp->t_maxseg = old_maxseg - 40;
14010 					bbr_log_msgsize_fail(bbr, tp, len, maxseg, mtu, 0, tso, cts);
14011 				}
14012 				/*
14013 				 * Nuke all other things that can interfere
14014 				 * with slot
14015 				 */
14016 				if ((tot_len + len) && (len >= tp->t_maxseg)) {
14017 					slot = bbr_get_pacing_delay(bbr,
14018 					    bbr->r_ctl.rc_bbr_hptsi_gain,
14019 					    (tot_len + len), cts, 0);
14020 					if (slot < bbr_error_base_paceout)
14021 						slot = (bbr_error_base_paceout + 2) << bbr->oerror_cnt;
14022 				} else
14023 					slot = (bbr_error_base_paceout + 2) << bbr->oerror_cnt;
14024 				bbr->rc_output_starts_timer = 1;
14025 				bbr_start_hpts_timer(bbr, tp, cts, 10, slot,
14026 				    tot_len);
14027 				return (error);
14028 			}
14029 		case EPERM:
14030 			tp->t_softerror = error;
14031 			/* Fall through */
14032 		case EHOSTDOWN:
14033 		case EHOSTUNREACH:
14034 		case ENETDOWN:
14035 		case ENETUNREACH:
14036 			if (TCPS_HAVERCVDSYN(tp->t_state)) {
14037 				tp->t_softerror = error;
14038 			}
14039 			/* FALLTHROUGH */
14040 		default:
14041 			slot = (bbr_error_base_paceout + 3) << bbr->oerror_cnt;
14042 			bbr->rc_output_starts_timer = 1;
14043 			bbr_start_hpts_timer(bbr, tp, cts, 11, slot, 0);
14044 			return (error);
14045 		}
14046 #ifdef STATS
14047 	} else if (((tp->t_flags & TF_GPUTINPROG) == 0) &&
14048 		    len &&
14049 		    (rsm == NULL) &&
14050 	    (bbr->rc_in_persist == 0)) {
14051 		tp->gput_seq = bbr_seq;
14052 		tp->gput_ack = bbr_seq +
14053 		    min(sbavail(&so->so_snd) - sb_offset, sendwin);
14054 		tp->gput_ts = cts;
14055 		tp->t_flags |= TF_GPUTINPROG;
14056 #endif
14057 	}
14058 	KMOD_TCPSTAT_INC(tcps_sndtotal);
14059 	if ((bbr->bbr_hdw_pace_ena) &&
14060 	    (bbr->bbr_attempt_hdwr_pace == 0) &&
14061 	    (bbr->rc_past_init_win) &&
14062 	    (bbr->rc_bbr_state != BBR_STATE_STARTUP) &&
14063 	    (get_filter_value(&bbr->r_ctl.rc_delrate)) &&
14064 	    (inp->inp_route.ro_nh &&
14065 	     inp->inp_route.ro_nh->nh_ifp)) {
14066 		/*
14067 		 * We are past the initial window and
14068 		 * have at least one measurement so we
14069 		 * could use hardware pacing if its available.
14070 		 * We have an interface and we have not attempted
14071 		 * to setup hardware pacing, lets try to now.
14072 		 */
14073 		uint64_t rate_wanted;
14074 		int err = 0;
14075 
14076 		rate_wanted = bbr_get_hardware_rate(bbr);
14077 		bbr->bbr_attempt_hdwr_pace = 1;
14078 		bbr->r_ctl.crte = tcp_set_pacing_rate(bbr->rc_tp,
14079 						      inp->inp_route.ro_nh->nh_ifp,
14080 						      rate_wanted,
14081 						      (RS_PACING_GEQ|RS_PACING_SUB_OK),
14082 						      &err);
14083 		if (bbr->r_ctl.crte) {
14084 			bbr_type_log_hdwr_pacing(bbr,
14085 						 bbr->r_ctl.crte->ptbl->rs_ifp,
14086 						 rate_wanted,
14087 						 bbr->r_ctl.crte->rate,
14088 						 __LINE__, cts, err);
14089 			BBR_STAT_INC(bbr_hdwr_rl_add_ok);
14090 			counter_u64_add(bbr_flows_nohdwr_pacing, -1);
14091 			counter_u64_add(bbr_flows_whdwr_pacing, 1);
14092 			bbr->bbr_hdrw_pacing = 1;
14093 			/* Now what is our gain status? */
14094 			if (bbr->r_ctl.crte->rate < rate_wanted) {
14095 				/* We have a problem */
14096 				bbr_setup_less_of_rate(bbr, cts,
14097 						       bbr->r_ctl.crte->rate, rate_wanted);
14098 			} else {
14099 				/* We are good */
14100 				bbr->gain_is_limited = 0;
14101 				bbr->skip_gain = 0;
14102 			}
14103 			tcp_bbr_tso_size_check(bbr, cts);
14104 		} else {
14105 			bbr_type_log_hdwr_pacing(bbr,
14106 						 inp->inp_route.ro_nh->nh_ifp,
14107 						 rate_wanted,
14108 						 0,
14109 						 __LINE__, cts, err);
14110 			BBR_STAT_INC(bbr_hdwr_rl_add_fail);
14111 		}
14112 	}
14113 	if (bbr->bbr_hdrw_pacing) {
14114 		/*
14115 		 * Worry about cases where the route
14116 		 * changes or something happened that we
14117 		 * lost our hardware pacing possibly during
14118 		 * the last ip_output call.
14119 		 */
14120 		if (inp->inp_snd_tag == NULL) {
14121 			/* A change during ip output disabled hw pacing? */
14122 			bbr->bbr_hdrw_pacing = 0;
14123 		} else if ((inp->inp_route.ro_nh == NULL) ||
14124 		    (inp->inp_route.ro_nh->nh_ifp != inp->inp_snd_tag->ifp)) {
14125 			/*
14126 			 * We had an interface or route change,
14127 			 * detach from the current hdwr pacing
14128 			 * and setup to re-attempt next go
14129 			 * round.
14130 			 */
14131 			bbr->bbr_hdrw_pacing = 0;
14132 			bbr->bbr_attempt_hdwr_pace = 0;
14133 			tcp_rel_pacing_rate(bbr->r_ctl.crte, bbr->rc_tp);
14134 			tcp_bbr_tso_size_check(bbr, cts);
14135 		}
14136 	}
14137 	/*
14138 	 * Data sent (as far as we can tell). If this advertises a larger
14139 	 * window than any other segment, then remember the size of the
14140 	 * advertised window. Any pending ACK has now been sent.
14141 	 */
14142 	if (SEQ_GT(tp->rcv_nxt + recwin, tp->rcv_adv))
14143 		tp->rcv_adv = tp->rcv_nxt + recwin;
14144 
14145 	tp->last_ack_sent = tp->rcv_nxt;
14146 	if ((error == 0) &&
14147 	    (bbr->r_ctl.rc_pace_max_segs > tp->t_maxseg) &&
14148 	    (doing_tlp == 0) &&
14149 	    (tso == 0) &&
14150 	    (len > 0) &&
14151 	    ((flags & TH_RST) == 0) &&
14152 	    ((flags & TH_SYN) == 0) &&
14153 	    (IN_RECOVERY(tp->t_flags) == 0) &&
14154 	    (bbr->rc_in_persist == 0) &&
14155 	    (tot_len < bbr->r_ctl.rc_pace_max_segs)) {
14156 		/*
14157 		 * For non-tso we need to goto again until we have sent out
14158 		 * enough data to match what we are hptsi out every hptsi
14159 		 * interval.
14160 		 */
14161 		if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
14162 			/* Make sure snd_nxt is drug up */
14163 			tp->snd_nxt = tp->snd_max;
14164 		}
14165 		if (rsm != NULL) {
14166 			rsm = NULL;
14167 			goto skip_again;
14168 		}
14169 		rsm = NULL;
14170 		sack_rxmit = 0;
14171 		tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
14172 		goto again;
14173 	}
14174 skip_again:
14175 	if ((error == 0) && (flags & TH_FIN))
14176 		tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_FIN);
14177 	if ((error == 0) && (flags & TH_RST))
14178 		tcp_log_end_status(tp, TCP_EI_STATUS_SERVER_RST);
14179 	if (((flags & (TH_RST | TH_SYN | TH_FIN)) == 0) && tot_len) {
14180 		/*
14181 		 * Calculate/Re-Calculate the hptsi slot in usecs based on
14182 		 * what we have sent so far
14183 		 */
14184 		slot = bbr_get_pacing_delay(bbr, bbr->r_ctl.rc_bbr_hptsi_gain, tot_len, cts, 0);
14185 		if (bbr->rc_no_pacing)
14186 			slot = 0;
14187 	}
14188 	tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
14189 enobufs:
14190 	if (bbr->rc_use_google == 0)
14191 		bbr_check_bbr_for_state(bbr, cts, __LINE__, 0);
14192 	bbr_cwnd_limiting(tp, bbr, ctf_flight_size(tp, (bbr->r_ctl.rc_sacked +
14193 							bbr->r_ctl.rc_lost_bytes)));
14194 	bbr->rc_output_starts_timer = 1;
14195 	if (bbr->bbr_use_rack_cheat &&
14196 	    (more_to_rxt ||
14197 	     ((bbr->r_ctl.rc_resend = bbr_check_recovery_mode(tp, bbr, cts)) != NULL))) {
14198 		/* Rack cheats and shotguns out all rxt's 1ms apart */
14199 		if (slot > 1000)
14200 			slot = 1000;
14201 	}
14202 	if (bbr->bbr_hdrw_pacing && (bbr->hw_pacing_set == 0)) {
14203 		/*
14204 		 * We don't change the tso size until some number of sends
14205 		 * to give the hardware commands time to get down
14206 		 * to the interface.
14207 		 */
14208 		bbr->r_ctl.bbr_hdwr_cnt_noset_snt++;
14209 		if (bbr->r_ctl.bbr_hdwr_cnt_noset_snt >= bbr_hdwr_pacing_delay_cnt) {
14210 			bbr->hw_pacing_set = 1;
14211 			tcp_bbr_tso_size_check(bbr, cts);
14212 		}
14213 	}
14214 	bbr_start_hpts_timer(bbr, tp, cts, 12, slot, tot_len);
14215 	if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
14216 		/* Make sure snd_nxt is drug up */
14217 		tp->snd_nxt = tp->snd_max;
14218 	}
14219 	return (error);
14220 
14221 }
14222 
14223 /*
14224  * See bbr_output_wtime() for return values.
14225  */
14226 static int
14227 bbr_output(struct tcpcb *tp)
14228 {
14229 	int32_t ret;
14230 	struct timeval tv;
14231 	struct tcp_bbr *bbr;
14232 
14233 	NET_EPOCH_ASSERT();
14234 
14235 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
14236 	INP_WLOCK_ASSERT(tp->t_inpcb);
14237 	(void)tcp_get_usecs(&tv);
14238 	ret = bbr_output_wtime(tp, &tv);
14239 	return (ret);
14240 }
14241 
14242 static void
14243 bbr_mtu_chg(struct tcpcb *tp)
14244 {
14245 	struct tcp_bbr *bbr;
14246 	struct bbr_sendmap *rsm, *frsm = NULL;
14247 	uint32_t maxseg;
14248 
14249 	/*
14250 	 * The MTU has changed. a) Clear the sack filter. b) Mark everything
14251 	 * over the current size as SACK_PASS so a retransmit will occur.
14252 	 */
14253 
14254 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
14255 	maxseg = tp->t_maxseg - bbr->rc_last_options;
14256 	sack_filter_clear(&bbr->r_ctl.bbr_sf, tp->snd_una);
14257 	TAILQ_FOREACH(rsm, &bbr->r_ctl.rc_map, r_next) {
14258 		/* Don't mess with ones acked (by sack?) */
14259 		if (rsm->r_flags & BBR_ACKED)
14260 			continue;
14261 		if ((rsm->r_end - rsm->r_start) > maxseg) {
14262 			/*
14263 			 * We mark sack-passed on all the previous large
14264 			 * sends we did. This will force them to retransmit.
14265 			 */
14266 			rsm->r_flags |= BBR_SACK_PASSED;
14267 			if (((rsm->r_flags & BBR_MARKED_LOST) == 0) &&
14268 			    bbr_is_lost(bbr, rsm, bbr->r_ctl.rc_rcvtime)) {
14269 				bbr->r_ctl.rc_lost_bytes += rsm->r_end - rsm->r_start;
14270 				bbr->r_ctl.rc_lost += rsm->r_end - rsm->r_start;
14271 				rsm->r_flags |= BBR_MARKED_LOST;
14272 			}
14273 			if (frsm == NULL)
14274 				frsm = rsm;
14275 		}
14276 	}
14277 	if (frsm) {
14278 		bbr->r_ctl.rc_resend = frsm;
14279 	}
14280 }
14281 
14282 /*
14283  * bbr_ctloutput() must drop the inpcb lock before performing copyin on
14284  * socket option arguments.  When it re-acquires the lock after the copy, it
14285  * has to revalidate that the connection is still valid for the socket
14286  * option.
14287  */
14288 static int
14289 bbr_set_sockopt(struct socket *so, struct sockopt *sopt,
14290 		struct inpcb *inp, struct tcpcb *tp, struct tcp_bbr *bbr)
14291 {
14292 	struct epoch_tracker et;
14293 	int32_t error = 0, optval;
14294 
14295 	switch (sopt->sopt_name) {
14296 	case TCP_RACK_PACE_MAX_SEG:
14297 	case TCP_RACK_MIN_TO:
14298 	case TCP_RACK_REORD_THRESH:
14299 	case TCP_RACK_REORD_FADE:
14300 	case TCP_RACK_TLP_THRESH:
14301 	case TCP_RACK_PKT_DELAY:
14302 	case TCP_BBR_ALGORITHM:
14303 	case TCP_BBR_TSLIMITS:
14304 	case TCP_BBR_IWINTSO:
14305 	case TCP_BBR_RECFORCE:
14306 	case TCP_BBR_STARTUP_PG:
14307 	case TCP_BBR_DRAIN_PG:
14308 	case TCP_BBR_RWND_IS_APP:
14309 	case TCP_BBR_PROBE_RTT_INT:
14310 	case TCP_BBR_PROBE_RTT_GAIN:
14311 	case TCP_BBR_PROBE_RTT_LEN:
14312 	case TCP_BBR_STARTUP_LOSS_EXIT:
14313 	case TCP_BBR_USEDEL_RATE:
14314 	case TCP_BBR_MIN_RTO:
14315 	case TCP_BBR_MAX_RTO:
14316 	case TCP_BBR_PACE_PER_SEC:
14317 	case TCP_DELACK:
14318 	case TCP_BBR_PACE_DEL_TAR:
14319 	case TCP_BBR_SEND_IWND_IN_TSO:
14320 	case TCP_BBR_EXTRA_STATE:
14321 	case TCP_BBR_UTTER_MAX_TSO:
14322 	case TCP_BBR_MIN_TOPACEOUT:
14323 	case TCP_BBR_FLOOR_MIN_TSO:
14324 	case TCP_BBR_TSTMP_RAISES:
14325 	case TCP_BBR_POLICER_DETECT:
14326 	case TCP_BBR_USE_RACK_CHEAT:
14327 	case TCP_DATA_AFTER_CLOSE:
14328 	case TCP_BBR_HDWR_PACE:
14329 	case TCP_BBR_PACE_SEG_MAX:
14330 	case TCP_BBR_PACE_SEG_MIN:
14331 	case TCP_BBR_PACE_CROSS:
14332 	case TCP_BBR_PACE_OH:
14333 #ifdef NETFLIX_PEAKRATE
14334 	case TCP_MAXPEAKRATE:
14335 #endif
14336 	case TCP_BBR_TMR_PACE_OH:
14337 	case TCP_BBR_RACK_RTT_USE:
14338 	case TCP_BBR_RETRAN_WTSO:
14339 		break;
14340 	default:
14341 		return (tcp_default_ctloutput(so, sopt, inp, tp));
14342 		break;
14343 	}
14344 	INP_WUNLOCK(inp);
14345 	error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
14346 	if (error)
14347 		return (error);
14348 	INP_WLOCK(inp);
14349 	if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
14350 		INP_WUNLOCK(inp);
14351 		return (ECONNRESET);
14352 	}
14353 	tp = intotcpcb(inp);
14354 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
14355 	switch (sopt->sopt_name) {
14356 	case TCP_BBR_PACE_PER_SEC:
14357 		BBR_OPTS_INC(tcp_bbr_pace_per_sec);
14358 		bbr->r_ctl.bbr_hptsi_per_second = optval;
14359 		break;
14360 	case TCP_BBR_PACE_DEL_TAR:
14361 		BBR_OPTS_INC(tcp_bbr_pace_del_tar);
14362 		bbr->r_ctl.bbr_hptsi_segments_delay_tar = optval;
14363 		break;
14364 	case TCP_BBR_PACE_SEG_MAX:
14365 		BBR_OPTS_INC(tcp_bbr_pace_seg_max);
14366 		bbr->r_ctl.bbr_hptsi_segments_max = optval;
14367 		break;
14368 	case TCP_BBR_PACE_SEG_MIN:
14369 		BBR_OPTS_INC(tcp_bbr_pace_seg_min);
14370 		bbr->r_ctl.bbr_hptsi_bytes_min = optval;
14371 		break;
14372 	case TCP_BBR_PACE_CROSS:
14373 		BBR_OPTS_INC(tcp_bbr_pace_cross);
14374 		bbr->r_ctl.bbr_cross_over = optval;
14375 		break;
14376 	case TCP_BBR_ALGORITHM:
14377 		BBR_OPTS_INC(tcp_bbr_algorithm);
14378 		if (optval && (bbr->rc_use_google == 0)) {
14379 			/* Turn on the google mode */
14380 			bbr_google_mode_on(bbr);
14381 			if ((optval > 3) && (optval < 500)) {
14382 				/*
14383 				 * Must be at least greater than .3%
14384 				 * and must be less than 50.0%.
14385 				 */
14386 				bbr->r_ctl.bbr_google_discount = optval;
14387 			}
14388 		} else if ((optval == 0) && (bbr->rc_use_google == 1)) {
14389 			/* Turn off the google mode */
14390 			bbr_google_mode_off(bbr);
14391 		}
14392 		break;
14393 	case TCP_BBR_TSLIMITS:
14394 		BBR_OPTS_INC(tcp_bbr_tslimits);
14395 		if (optval == 1)
14396 			bbr->rc_use_ts_limit = 1;
14397 		else if (optval == 0)
14398 			bbr->rc_use_ts_limit = 0;
14399 		else
14400 			error = EINVAL;
14401 		break;
14402 
14403 	case TCP_BBR_IWINTSO:
14404 		BBR_OPTS_INC(tcp_bbr_iwintso);
14405 		if ((optval >= 0) && (optval < 128)) {
14406 			uint32_t twin;
14407 
14408 			bbr->rc_init_win = optval;
14409 			twin = bbr_initial_cwnd(bbr, tp);
14410 			if ((bbr->rc_past_init_win == 0) && (twin > tp->snd_cwnd))
14411 				tp->snd_cwnd = twin;
14412 			else
14413 				error = EBUSY;
14414 		} else
14415 			error = EINVAL;
14416 		break;
14417 	case TCP_BBR_STARTUP_PG:
14418 		BBR_OPTS_INC(tcp_bbr_startup_pg);
14419 		if ((optval > 0) && (optval < BBR_MAX_GAIN_VALUE)) {
14420 			bbr->r_ctl.rc_startup_pg = optval;
14421 			if (bbr->rc_bbr_state == BBR_STATE_STARTUP) {
14422 				bbr->r_ctl.rc_bbr_hptsi_gain = optval;
14423 			}
14424 		} else
14425 			error = EINVAL;
14426 		break;
14427 	case TCP_BBR_DRAIN_PG:
14428 		BBR_OPTS_INC(tcp_bbr_drain_pg);
14429 		if ((optval > 0) && (optval < BBR_MAX_GAIN_VALUE))
14430 			bbr->r_ctl.rc_drain_pg = optval;
14431 		else
14432 			error = EINVAL;
14433 		break;
14434 	case TCP_BBR_PROBE_RTT_LEN:
14435 		BBR_OPTS_INC(tcp_bbr_probertt_len);
14436 		if (optval <= 1)
14437 			reset_time_small(&bbr->r_ctl.rc_rttprop, (optval * USECS_IN_SECOND));
14438 		else
14439 			error = EINVAL;
14440 		break;
14441 	case TCP_BBR_PROBE_RTT_GAIN:
14442 		BBR_OPTS_INC(tcp_bbr_probertt_gain);
14443 		if (optval <= BBR_UNIT)
14444 			bbr->r_ctl.bbr_rttprobe_gain_val = optval;
14445 		else
14446 			error = EINVAL;
14447 		break;
14448 	case TCP_BBR_PROBE_RTT_INT:
14449 		BBR_OPTS_INC(tcp_bbr_probe_rtt_int);
14450 		if (optval > 1000)
14451 			bbr->r_ctl.rc_probertt_int = optval;
14452 		else
14453 			error = EINVAL;
14454 		break;
14455 	case TCP_BBR_MIN_TOPACEOUT:
14456 		BBR_OPTS_INC(tcp_bbr_topaceout);
14457 		if (optval == 0) {
14458 			bbr->no_pacing_until = 0;
14459 			bbr->rc_no_pacing = 0;
14460 		} else if (optval <= 0x00ff) {
14461 			bbr->no_pacing_until = optval;
14462 			if ((bbr->r_ctl.rc_pkt_epoch < bbr->no_pacing_until) &&
14463 			    (bbr->rc_bbr_state == BBR_STATE_STARTUP)){
14464 				/* Turn on no pacing */
14465 				bbr->rc_no_pacing = 1;
14466 			}
14467 		} else
14468 			error = EINVAL;
14469 		break;
14470 	case TCP_BBR_STARTUP_LOSS_EXIT:
14471 		BBR_OPTS_INC(tcp_bbr_startup_loss_exit);
14472 		bbr->rc_loss_exit = optval;
14473 		break;
14474 	case TCP_BBR_USEDEL_RATE:
14475 		error = EINVAL;
14476 		break;
14477 	case TCP_BBR_MIN_RTO:
14478 		BBR_OPTS_INC(tcp_bbr_min_rto);
14479 		bbr->r_ctl.rc_min_rto_ms = optval;
14480 		break;
14481 	case TCP_BBR_MAX_RTO:
14482 		BBR_OPTS_INC(tcp_bbr_max_rto);
14483 		bbr->rc_max_rto_sec = optval;
14484 		break;
14485 	case TCP_RACK_MIN_TO:
14486 		/* Minimum time between rack t-o's in ms */
14487 		BBR_OPTS_INC(tcp_rack_min_to);
14488 		bbr->r_ctl.rc_min_to = optval;
14489 		break;
14490 	case TCP_RACK_REORD_THRESH:
14491 		/* RACK reorder threshold (shift amount) */
14492 		BBR_OPTS_INC(tcp_rack_reord_thresh);
14493 		if ((optval > 0) && (optval < 31))
14494 			bbr->r_ctl.rc_reorder_shift = optval;
14495 		else
14496 			error = EINVAL;
14497 		break;
14498 	case TCP_RACK_REORD_FADE:
14499 		/* Does reordering fade after ms time */
14500 		BBR_OPTS_INC(tcp_rack_reord_fade);
14501 		bbr->r_ctl.rc_reorder_fade = optval;
14502 		break;
14503 	case TCP_RACK_TLP_THRESH:
14504 		/* RACK TLP theshold i.e. srtt+(srtt/N) */
14505 		BBR_OPTS_INC(tcp_rack_tlp_thresh);
14506 		if (optval)
14507 			bbr->rc_tlp_threshold = optval;
14508 		else
14509 			error = EINVAL;
14510 		break;
14511 	case TCP_BBR_USE_RACK_CHEAT:
14512 		BBR_OPTS_INC(tcp_use_rackcheat);
14513 		if (bbr->rc_use_google) {
14514 			error = EINVAL;
14515 			break;
14516 		}
14517 		BBR_OPTS_INC(tcp_rack_cheat);
14518 		if (optval)
14519 			bbr->bbr_use_rack_cheat = 1;
14520 		else
14521 			bbr->bbr_use_rack_cheat = 0;
14522 		break;
14523 	case TCP_BBR_FLOOR_MIN_TSO:
14524 		BBR_OPTS_INC(tcp_utter_max_tso);
14525 		if ((optval >= 0) && (optval < 40))
14526 			bbr->r_ctl.bbr_hptsi_segments_floor = optval;
14527 		else
14528 			error = EINVAL;
14529 		break;
14530 	case TCP_BBR_UTTER_MAX_TSO:
14531 		BBR_OPTS_INC(tcp_utter_max_tso);
14532 		if ((optval >= 0) && (optval < 0xffff))
14533 			bbr->r_ctl.bbr_utter_max = optval;
14534 		else
14535 			error = EINVAL;
14536 		break;
14537 
14538 	case TCP_BBR_EXTRA_STATE:
14539 		BBR_OPTS_INC(tcp_extra_state);
14540 		if (optval)
14541 			bbr->rc_use_idle_restart = 1;
14542 		else
14543 			bbr->rc_use_idle_restart = 0;
14544 		break;
14545 	case TCP_BBR_SEND_IWND_IN_TSO:
14546 		BBR_OPTS_INC(tcp_iwnd_tso);
14547 		if (optval) {
14548 			bbr->bbr_init_win_cheat = 1;
14549 			if (bbr->rc_past_init_win == 0) {
14550 				uint32_t cts;
14551 				cts = tcp_get_usecs(&bbr->rc_tv);
14552 				tcp_bbr_tso_size_check(bbr, cts);
14553 			}
14554 		} else
14555 			bbr->bbr_init_win_cheat = 0;
14556 		break;
14557 	case TCP_BBR_HDWR_PACE:
14558 		BBR_OPTS_INC(tcp_hdwr_pacing);
14559 		if (optval){
14560 			bbr->bbr_hdw_pace_ena = 1;
14561 			bbr->bbr_attempt_hdwr_pace = 0;
14562 		} else {
14563 			bbr->bbr_hdw_pace_ena = 0;
14564 #ifdef RATELIMIT
14565 			if (bbr->bbr_hdrw_pacing) {
14566 				bbr->bbr_hdrw_pacing = 0;
14567 				in_pcbdetach_txrtlmt(bbr->rc_inp);
14568 			}
14569 #endif
14570 		}
14571 		break;
14572 
14573 	case TCP_DELACK:
14574 		BBR_OPTS_INC(tcp_delack);
14575 		if (optval < 100) {
14576 			if (optval == 0) /* off */
14577 				tp->t_delayed_ack = 0;
14578 			else if (optval == 1) /* on which is 2 */
14579 				tp->t_delayed_ack = 2;
14580 			else /* higher than 2 and less than 100 */
14581 				tp->t_delayed_ack = optval;
14582 			if (tp->t_flags & TF_DELACK) {
14583 				tp->t_flags &= ~TF_DELACK;
14584 				tp->t_flags |= TF_ACKNOW;
14585 				NET_EPOCH_ENTER(et);
14586 				bbr_output(tp);
14587 				NET_EPOCH_EXIT(et);
14588 			}
14589 		} else
14590 			error = EINVAL;
14591 		break;
14592 	case TCP_RACK_PKT_DELAY:
14593 		/* RACK added ms i.e. rack-rtt + reord + N */
14594 		BBR_OPTS_INC(tcp_rack_pkt_delay);
14595 		bbr->r_ctl.rc_pkt_delay = optval;
14596 		break;
14597 #ifdef NETFLIX_PEAKRATE
14598 	case TCP_MAXPEAKRATE:
14599 		BBR_OPTS_INC(tcp_maxpeak);
14600 		error = tcp_set_maxpeakrate(tp, optval);
14601 		if (!error)
14602 			tp->t_peakrate_thr = tp->t_maxpeakrate;
14603 		break;
14604 #endif
14605 	case TCP_BBR_RETRAN_WTSO:
14606 		BBR_OPTS_INC(tcp_retran_wtso);
14607 		if (optval)
14608 			bbr->rc_resends_use_tso = 1;
14609 		else
14610 			bbr->rc_resends_use_tso = 0;
14611 		break;
14612 	case TCP_DATA_AFTER_CLOSE:
14613 		BBR_OPTS_INC(tcp_data_ac);
14614 		if (optval)
14615 			bbr->rc_allow_data_af_clo = 1;
14616 		else
14617 			bbr->rc_allow_data_af_clo = 0;
14618 		break;
14619 	case TCP_BBR_POLICER_DETECT:
14620 		BBR_OPTS_INC(tcp_policer_det);
14621 		if (bbr->rc_use_google == 0)
14622 			error = EINVAL;
14623 		else if (optval)
14624 			bbr->r_use_policer = 1;
14625 		else
14626 			bbr->r_use_policer = 0;
14627 		break;
14628 
14629 	case TCP_BBR_TSTMP_RAISES:
14630 		BBR_OPTS_INC(tcp_ts_raises);
14631 		if (optval)
14632 			bbr->ts_can_raise = 1;
14633 		else
14634 			bbr->ts_can_raise = 0;
14635 		break;
14636 	case TCP_BBR_TMR_PACE_OH:
14637 		BBR_OPTS_INC(tcp_pacing_oh_tmr);
14638 		if (bbr->rc_use_google) {
14639 			error = EINVAL;
14640 		} else {
14641 			if (optval)
14642 				bbr->r_ctl.rc_incr_tmrs = 1;
14643 			else
14644 				bbr->r_ctl.rc_incr_tmrs = 0;
14645 		}
14646 		break;
14647 	case TCP_BBR_PACE_OH:
14648 		BBR_OPTS_INC(tcp_pacing_oh);
14649 		if (bbr->rc_use_google) {
14650 			error = EINVAL;
14651 		} else {
14652 			if (optval > (BBR_INCL_TCP_OH|
14653 				      BBR_INCL_IP_OH|
14654 				      BBR_INCL_ENET_OH)) {
14655 				error = EINVAL;
14656 				break;
14657 			}
14658 			if (optval & BBR_INCL_TCP_OH)
14659 				bbr->r_ctl.rc_inc_tcp_oh = 1;
14660 			else
14661 				bbr->r_ctl.rc_inc_tcp_oh = 0;
14662 			if (optval & BBR_INCL_IP_OH)
14663 				bbr->r_ctl.rc_inc_ip_oh = 1;
14664 			else
14665 				bbr->r_ctl.rc_inc_ip_oh = 0;
14666 			if (optval & BBR_INCL_ENET_OH)
14667 				bbr->r_ctl.rc_inc_enet_oh = 1;
14668 			else
14669 				bbr->r_ctl.rc_inc_enet_oh = 0;
14670 		}
14671 		break;
14672 	default:
14673 		return (tcp_default_ctloutput(so, sopt, inp, tp));
14674 		break;
14675 	}
14676 #ifdef NETFLIX_STATS
14677 	tcp_log_socket_option(tp, sopt->sopt_name, optval, error);
14678 #endif
14679 	INP_WUNLOCK(inp);
14680 	return (error);
14681 }
14682 
14683 /*
14684  * return 0 on success, error-num on failure
14685  */
14686 static int
14687 bbr_get_sockopt(struct socket *so, struct sockopt *sopt,
14688     struct inpcb *inp, struct tcpcb *tp, struct tcp_bbr *bbr)
14689 {
14690 	int32_t error, optval;
14691 
14692 	/*
14693 	 * Because all our options are either boolean or an int, we can just
14694 	 * pull everything into optval and then unlock and copy. If we ever
14695 	 * add a option that is not a int, then this will have quite an
14696 	 * impact to this routine.
14697 	 */
14698 	switch (sopt->sopt_name) {
14699 	case TCP_BBR_PACE_PER_SEC:
14700 		optval = bbr->r_ctl.bbr_hptsi_per_second;
14701 		break;
14702 	case TCP_BBR_PACE_DEL_TAR:
14703 		optval = bbr->r_ctl.bbr_hptsi_segments_delay_tar;
14704 		break;
14705 	case TCP_BBR_PACE_SEG_MAX:
14706 		optval = bbr->r_ctl.bbr_hptsi_segments_max;
14707 		break;
14708 	case TCP_BBR_MIN_TOPACEOUT:
14709 		optval = bbr->no_pacing_until;
14710 		break;
14711 	case TCP_BBR_PACE_SEG_MIN:
14712 		optval = bbr->r_ctl.bbr_hptsi_bytes_min;
14713 		break;
14714 	case TCP_BBR_PACE_CROSS:
14715 		optval = bbr->r_ctl.bbr_cross_over;
14716 		break;
14717 	case TCP_BBR_ALGORITHM:
14718 		optval = bbr->rc_use_google;
14719 		break;
14720 	case TCP_BBR_TSLIMITS:
14721 		optval = bbr->rc_use_ts_limit;
14722 		break;
14723 	case TCP_BBR_IWINTSO:
14724 		optval = bbr->rc_init_win;
14725 		break;
14726 	case TCP_BBR_STARTUP_PG:
14727 		optval = bbr->r_ctl.rc_startup_pg;
14728 		break;
14729 	case TCP_BBR_DRAIN_PG:
14730 		optval = bbr->r_ctl.rc_drain_pg;
14731 		break;
14732 	case TCP_BBR_PROBE_RTT_INT:
14733 		optval = bbr->r_ctl.rc_probertt_int;
14734 		break;
14735 	case TCP_BBR_PROBE_RTT_LEN:
14736 		optval = (bbr->r_ctl.rc_rttprop.cur_time_limit / USECS_IN_SECOND);
14737 		break;
14738 	case TCP_BBR_PROBE_RTT_GAIN:
14739 		optval = bbr->r_ctl.bbr_rttprobe_gain_val;
14740 		break;
14741 	case TCP_BBR_STARTUP_LOSS_EXIT:
14742 		optval = bbr->rc_loss_exit;
14743 		break;
14744 	case TCP_BBR_USEDEL_RATE:
14745 		error = EINVAL;
14746 		break;
14747 	case TCP_BBR_MIN_RTO:
14748 		optval = bbr->r_ctl.rc_min_rto_ms;
14749 		break;
14750 	case TCP_BBR_MAX_RTO:
14751 		optval = bbr->rc_max_rto_sec;
14752 		break;
14753 	case TCP_RACK_PACE_MAX_SEG:
14754 		/* Max segments in a pace */
14755 		optval = bbr->r_ctl.rc_pace_max_segs;
14756 		break;
14757 	case TCP_RACK_MIN_TO:
14758 		/* Minimum time between rack t-o's in ms */
14759 		optval = bbr->r_ctl.rc_min_to;
14760 		break;
14761 	case TCP_RACK_REORD_THRESH:
14762 		/* RACK reorder threshold (shift amount) */
14763 		optval = bbr->r_ctl.rc_reorder_shift;
14764 		break;
14765 	case TCP_RACK_REORD_FADE:
14766 		/* Does reordering fade after ms time */
14767 		optval = bbr->r_ctl.rc_reorder_fade;
14768 		break;
14769 	case TCP_BBR_USE_RACK_CHEAT:
14770 		/* Do we use the rack cheat for rxt */
14771 		optval = bbr->bbr_use_rack_cheat;
14772 		break;
14773 	case TCP_BBR_FLOOR_MIN_TSO:
14774 		optval = bbr->r_ctl.bbr_hptsi_segments_floor;
14775 		break;
14776 	case TCP_BBR_UTTER_MAX_TSO:
14777 		optval = bbr->r_ctl.bbr_utter_max;
14778 		break;
14779 	case TCP_BBR_SEND_IWND_IN_TSO:
14780 		/* Do we send TSO size segments initially */
14781 		optval = bbr->bbr_init_win_cheat;
14782 		break;
14783 	case TCP_BBR_EXTRA_STATE:
14784 		optval = bbr->rc_use_idle_restart;
14785 		break;
14786 	case TCP_RACK_TLP_THRESH:
14787 		/* RACK TLP theshold i.e. srtt+(srtt/N) */
14788 		optval = bbr->rc_tlp_threshold;
14789 		break;
14790 	case TCP_RACK_PKT_DELAY:
14791 		/* RACK added ms i.e. rack-rtt + reord + N */
14792 		optval = bbr->r_ctl.rc_pkt_delay;
14793 		break;
14794 	case TCP_BBR_RETRAN_WTSO:
14795 		optval = bbr->rc_resends_use_tso;
14796 		break;
14797 	case TCP_DATA_AFTER_CLOSE:
14798 		optval = bbr->rc_allow_data_af_clo;
14799 		break;
14800 	case TCP_DELACK:
14801 		optval = tp->t_delayed_ack;
14802 		break;
14803 	case TCP_BBR_HDWR_PACE:
14804 		optval = bbr->bbr_hdw_pace_ena;
14805 		break;
14806 	case TCP_BBR_POLICER_DETECT:
14807 		optval = bbr->r_use_policer;
14808 		break;
14809 	case TCP_BBR_TSTMP_RAISES:
14810 		optval = bbr->ts_can_raise;
14811 		break;
14812 	case TCP_BBR_TMR_PACE_OH:
14813 		optval = bbr->r_ctl.rc_incr_tmrs;
14814 		break;
14815 	case TCP_BBR_PACE_OH:
14816 		optval = 0;
14817 		if (bbr->r_ctl.rc_inc_tcp_oh)
14818 			optval |= BBR_INCL_TCP_OH;
14819 		if (bbr->r_ctl.rc_inc_ip_oh)
14820 			optval |= BBR_INCL_IP_OH;
14821 		if (bbr->r_ctl.rc_inc_enet_oh)
14822 			optval |= BBR_INCL_ENET_OH;
14823 		break;
14824 	default:
14825 		return (tcp_default_ctloutput(so, sopt, inp, tp));
14826 		break;
14827 	}
14828 	INP_WUNLOCK(inp);
14829 	error = sooptcopyout(sopt, &optval, sizeof optval);
14830 	return (error);
14831 }
14832 
14833 /*
14834  * return 0 on success, error-num on failure
14835  */
14836 static int
14837 bbr_ctloutput(struct socket *so, struct sockopt *sopt, struct inpcb *inp, struct tcpcb *tp)
14838 {
14839 	int32_t error = EINVAL;
14840 	struct tcp_bbr *bbr;
14841 
14842 	bbr = (struct tcp_bbr *)tp->t_fb_ptr;
14843 	if (bbr == NULL) {
14844 		/* Huh? */
14845 		goto out;
14846 	}
14847 	if (sopt->sopt_dir == SOPT_SET) {
14848 		return (bbr_set_sockopt(so, sopt, inp, tp, bbr));
14849 	} else if (sopt->sopt_dir == SOPT_GET) {
14850 		return (bbr_get_sockopt(so, sopt, inp, tp, bbr));
14851 	}
14852 out:
14853 	INP_WUNLOCK(inp);
14854 	return (error);
14855 }
14856 
14857 static int
14858 bbr_pru_options(struct tcpcb *tp, int flags)
14859 {
14860 	if (flags & PRUS_OOB)
14861 		return (EOPNOTSUPP);
14862 	return (0);
14863 }
14864 
14865 struct tcp_function_block __tcp_bbr = {
14866 	.tfb_tcp_block_name = __XSTRING(STACKNAME),
14867 	.tfb_tcp_output = bbr_output,
14868 	.tfb_do_queued_segments = ctf_do_queued_segments,
14869 	.tfb_do_segment_nounlock = bbr_do_segment_nounlock,
14870 	.tfb_tcp_do_segment = bbr_do_segment,
14871 	.tfb_tcp_ctloutput = bbr_ctloutput,
14872 	.tfb_tcp_fb_init = bbr_init,
14873 	.tfb_tcp_fb_fini = bbr_fini,
14874 	.tfb_tcp_timer_stop_all = bbr_stopall,
14875 	.tfb_tcp_timer_activate = bbr_timer_activate,
14876 	.tfb_tcp_timer_active = bbr_timer_active,
14877 	.tfb_tcp_timer_stop = bbr_timer_stop,
14878 	.tfb_tcp_rexmit_tmr = bbr_remxt_tmr,
14879 	.tfb_tcp_handoff_ok = bbr_handoff_ok,
14880 	.tfb_tcp_mtu_chg = bbr_mtu_chg,
14881 	.tfb_pru_options = bbr_pru_options,
14882 };
14883 
14884 static const char *bbr_stack_names[] = {
14885 	__XSTRING(STACKNAME),
14886 #ifdef STACKALIAS
14887 	__XSTRING(STACKALIAS),
14888 #endif
14889 };
14890 
14891 static bool bbr_mod_inited = false;
14892 
14893 static int
14894 tcp_addbbr(module_t mod, int32_t type, void *data)
14895 {
14896 	int32_t err = 0;
14897 	int num_stacks;
14898 
14899 	switch (type) {
14900 	case MOD_LOAD:
14901 		printf("Attempting to load " __XSTRING(MODNAME) "\n");
14902 		bbr_zone = uma_zcreate(__XSTRING(MODNAME) "_map",
14903 		    sizeof(struct bbr_sendmap),
14904 		    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
14905 		bbr_pcb_zone = uma_zcreate(__XSTRING(MODNAME) "_pcb",
14906 		    sizeof(struct tcp_bbr),
14907 		    NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
14908 		sysctl_ctx_init(&bbr_sysctl_ctx);
14909 		bbr_sysctl_root = SYSCTL_ADD_NODE(&bbr_sysctl_ctx,
14910 		    SYSCTL_STATIC_CHILDREN(_net_inet_tcp),
14911 		    OID_AUTO,
14912 #ifdef STACKALIAS
14913 		    __XSTRING(STACKALIAS),
14914 #else
14915 		    __XSTRING(STACKNAME),
14916 #endif
14917 		    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
14918 		    "");
14919 		if (bbr_sysctl_root == NULL) {
14920 			printf("Failed to add sysctl node\n");
14921 			err = EFAULT;
14922 			goto free_uma;
14923 		}
14924 		bbr_init_sysctls();
14925 		num_stacks = nitems(bbr_stack_names);
14926 		err = register_tcp_functions_as_names(&__tcp_bbr, M_WAITOK,
14927 		    bbr_stack_names, &num_stacks);
14928 		if (err) {
14929 			printf("Failed to register %s stack name for "
14930 			    "%s module\n", bbr_stack_names[num_stacks],
14931 			    __XSTRING(MODNAME));
14932 			sysctl_ctx_free(&bbr_sysctl_ctx);
14933 	free_uma:
14934 			uma_zdestroy(bbr_zone);
14935 			uma_zdestroy(bbr_pcb_zone);
14936 			bbr_counter_destroy();
14937 			printf("Failed to register " __XSTRING(MODNAME)
14938 			    " module err:%d\n", err);
14939 			return (err);
14940 		}
14941 		tcp_lro_reg_mbufq();
14942 		bbr_mod_inited = true;
14943 		printf(__XSTRING(MODNAME) " is now available\n");
14944 		break;
14945 	case MOD_QUIESCE:
14946 		err = deregister_tcp_functions(&__tcp_bbr, true, false);
14947 		break;
14948 	case MOD_UNLOAD:
14949 		err = deregister_tcp_functions(&__tcp_bbr, false, true);
14950 		if (err == EBUSY)
14951 			break;
14952 		if (bbr_mod_inited) {
14953 			uma_zdestroy(bbr_zone);
14954 			uma_zdestroy(bbr_pcb_zone);
14955 			sysctl_ctx_free(&bbr_sysctl_ctx);
14956 			bbr_counter_destroy();
14957 			printf(__XSTRING(MODNAME)
14958 			    " is now no longer available\n");
14959 			bbr_mod_inited = false;
14960 		}
14961 		tcp_lro_dereg_mbufq();
14962 		err = 0;
14963 		break;
14964 	default:
14965 		return (EOPNOTSUPP);
14966 	}
14967 	return (err);
14968 }
14969 
14970 static moduledata_t tcp_bbr = {
14971 	.name = __XSTRING(MODNAME),
14972 	    .evhand = tcp_addbbr,
14973 	    .priv = 0
14974 };
14975 
14976 MODULE_VERSION(MODNAME, 1);
14977 DECLARE_MODULE(MODNAME, tcp_bbr, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
14978 MODULE_DEPEND(MODNAME, tcphpts, 1, 1, 1);
14979