1 /*-
2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)tcp_timer.c 8.2 (Berkeley) 5/24/95
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD: releng/9.0/sys/netinet/tcp_timer.c 226574 2011-10-20 17:09:53Z np $");
34
35 #include "opt_inet6.h"
36 #include "opt_tcpdebug.h"
37
38 #include <sys/param.h>
39 #include <sys/kernel.h>
40 #include <sys/lock.h>
41 #include <sys/mbuf.h>
42 #include <sys/mutex.h>
43 #include <sys/protosw.h>
44 #include <sys/smp.h>
45 #include <sys/socket.h>
46 #include <sys/socketvar.h>
47 #include <sys/sysctl.h>
48 #include <sys/systm.h>
49
50 #include <net/if.h>
51 #include <net/route.h>
52 #include <net/vnet.h>
53
54 #include <netinet/cc.h>
55 #include <netinet/in.h>
56 #include <netinet/in_pcb.h>
57 #include <netinet/in_systm.h>
58 #ifdef INET6
59 #include <netinet6/in6_pcb.h>
60 #endif
61 #include <netinet/ip_var.h>
62 #include <netinet/tcp_fsm.h>
63 #include <netinet/tcp_timer.h>
64 #include <netinet/tcp_var.h>
65 #include <netinet/tcpip.h>
66 #ifdef TCPDEBUG
67 #include <netinet/tcp_debug.h>
68 #endif
69
70 int tcp_keepinit;
71 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit, CTLTYPE_INT|CTLFLAG_RW,
72 &tcp_keepinit, 0, sysctl_msec_to_ticks, "I", "time to establish connection");
73
74 int tcp_keepidle;
75 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle, CTLTYPE_INT|CTLFLAG_RW,
76 &tcp_keepidle, 0, sysctl_msec_to_ticks, "I", "time before keepalive probes begin");
77
78 int tcp_keepintvl;
79 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl, CTLTYPE_INT|CTLFLAG_RW,
80 &tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", "time between keepalive probes");
81
82 int tcp_delacktime;
83 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DELACKTIME, delacktime, CTLTYPE_INT|CTLFLAG_RW,
84 &tcp_delacktime, 0, sysctl_msec_to_ticks, "I",
85 "Time before a delayed ACK is sent");
86
87 int tcp_msl;
88 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl, CTLTYPE_INT|CTLFLAG_RW,
89 &tcp_msl, 0, sysctl_msec_to_ticks, "I", "Maximum segment lifetime");
90
91 int tcp_rexmit_min;
92 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_min, CTLTYPE_INT|CTLFLAG_RW,
93 &tcp_rexmit_min, 0, sysctl_msec_to_ticks, "I",
94 "Minimum Retransmission Timeout");
95
96 int tcp_rexmit_slop;
97 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_slop, CTLTYPE_INT|CTLFLAG_RW,
98 &tcp_rexmit_slop, 0, sysctl_msec_to_ticks, "I",
99 "Retransmission Timer Slop");
100
101 static int always_keepalive = 1;
102 SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive, CTLFLAG_RW,
103 &always_keepalive , 0, "Assume SO_KEEPALIVE on all TCP connections");
104
105 int tcp_fast_finwait2_recycle = 0;
106 SYSCTL_INT(_net_inet_tcp, OID_AUTO, fast_finwait2_recycle, CTLFLAG_RW,
107 &tcp_fast_finwait2_recycle, 0,
108 "Recycle closed FIN_WAIT_2 connections faster");
109
110 int tcp_finwait2_timeout;
111 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, finwait2_timeout, CTLTYPE_INT|CTLFLAG_RW,
112 &tcp_finwait2_timeout, 0, sysctl_msec_to_ticks, "I", "FIN-WAIT2 timeout");
113
114
115 static int tcp_keepcnt = TCPTV_KEEPCNT;
116 /* max idle probes */
117 int tcp_maxpersistidle;
118 /* max idle time in persist */
119 int tcp_maxidle;
120
121 static int per_cpu_timers = 0;
122 SYSCTL_INT(_net_inet_tcp, OID_AUTO, per_cpu_timers, CTLFLAG_RW,
123 &per_cpu_timers , 0, "run tcp timers on all cpus");
124
125 #define INP_CPU(inp) (per_cpu_timers ? (!CPU_ABSENT(((inp)->inp_flowid % (mp_maxid+1))) ? \
126 ((inp)->inp_flowid % (mp_maxid+1)) : curcpu) : 0)
127
128 /*
129 * Tcp protocol timeout routine called every 500 ms.
130 * Updates timestamps used for TCP
131 * causes finite state machine actions if timers expire.
132 */
133 void
134 tcp_slowtimo(void)
135 {
136 VNET_ITERATOR_DECL(vnet_iter);
137
138 VNET_LIST_RLOCK_NOSLEEP();
139 VNET_FOREACH(vnet_iter) {
140 CURVNET_SET(vnet_iter);
141 tcp_maxidle = tcp_keepcnt * tcp_keepintvl;
142 INP_INFO_WLOCK(&V_tcbinfo);
143 (void) tcp_tw_2msl_scan(0);
144 INP_INFO_WUNLOCK(&V_tcbinfo);
145 CURVNET_RESTORE();
146 }
147 VNET_LIST_RUNLOCK_NOSLEEP();
148 }
149
150 int tcp_syn_backoff[TCP_MAXRXTSHIFT + 1] =
151 { 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 64, 64 };
152
153 int tcp_backoff[TCP_MAXRXTSHIFT + 1] =
154 { 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 512, 512, 512 };
155
156 static int tcp_totbackoff = 2559; /* sum of tcp_backoff[] */
157
158 static int tcp_timer_race;
159 SYSCTL_INT(_net_inet_tcp, OID_AUTO, timer_race, CTLFLAG_RD, &tcp_timer_race,
160 0, "Count of t_inpcb races on tcp_discardcb");
161
162 /*
163 * TCP timer processing.
164 */
165
166 void
167 tcp_timer_delack(void *xtp)
168 {
169 struct tcpcb *tp = xtp;
170 struct inpcb *inp;
171 CURVNET_SET(tp->t_vnet);
172
173 inp = tp->t_inpcb;
174 /*
175 * XXXRW: While this assert is in fact correct, bugs in the tcpcb
176 * tear-down mean we need it as a work-around for races between
177 * timers and tcp_discardcb().
178 *
179 * KASSERT(inp != NULL, ("tcp_timer_delack: inp == NULL"));
180 */
181 if (inp == NULL) {
182 tcp_timer_race++;
183 CURVNET_RESTORE();
184 return;
185 }
186 INP_WLOCK(inp);
187 if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_delack)
188 || !callout_active(&tp->t_timers->tt_delack)) {
189 INP_WUNLOCK(inp);
190 CURVNET_RESTORE();
191 return;
192 }
193 callout_deactivate(&tp->t_timers->tt_delack);
194
195 tp->t_flags |= TF_ACKNOW;
196 TCPSTAT_INC(tcps_delack);
197 (void) tcp_output(tp);
198 INP_WUNLOCK(inp);
199 CURVNET_RESTORE();
200 }
201
202 void
203 tcp_timer_2msl(void *xtp)
204 {
205 struct tcpcb *tp = xtp;
206 struct inpcb *inp;
207 CURVNET_SET(tp->t_vnet);
208 #ifdef TCPDEBUG
209 int ostate;
210
211 ostate = tp->t_state;
212 #endif
213 /*
214 * XXXRW: Does this actually happen?
215 */
216 INP_INFO_WLOCK(&V_tcbinfo);
217 inp = tp->t_inpcb;
218 /*
219 * XXXRW: While this assert is in fact correct, bugs in the tcpcb
220 * tear-down mean we need it as a work-around for races between
221 * timers and tcp_discardcb().
222 *
223 * KASSERT(inp != NULL, ("tcp_timer_2msl: inp == NULL"));
224 */
225 if (inp == NULL) {
226 tcp_timer_race++;
227 INP_INFO_WUNLOCK(&V_tcbinfo);
228 CURVNET_RESTORE();
229 return;
230 }
231 INP_WLOCK(inp);
232 tcp_free_sackholes(tp);
233 if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_2msl) ||
234 !callout_active(&tp->t_timers->tt_2msl)) {
235 INP_WUNLOCK(tp->t_inpcb);
236 INP_INFO_WUNLOCK(&V_tcbinfo);
237 CURVNET_RESTORE();
238 return;
239 }
240 callout_deactivate(&tp->t_timers->tt_2msl);
241 /*
242 * 2 MSL timeout in shutdown went off. If we're closed but
243 * still waiting for peer to close and connection has been idle
244 * too long, or if 2MSL time is up from TIME_WAIT, delete connection
245 * control block. Otherwise, check again in a bit.
246 *
247 * If fastrecycle of FIN_WAIT_2, in FIN_WAIT_2 and receiver has closed,
248 * there's no point in hanging onto FIN_WAIT_2 socket. Just close it.
249 * Ignore fact that there were recent incoming segments.
250 */
251 if (tcp_fast_finwait2_recycle && tp->t_state == TCPS_FIN_WAIT_2 &&
252 tp->t_inpcb && tp->t_inpcb->inp_socket &&
253 (tp->t_inpcb->inp_socket->so_rcv.sb_state & SBS_CANTRCVMORE)) {
254 TCPSTAT_INC(tcps_finwait2_drops);
255 tp = tcp_close(tp);
256 } else {
257 if (tp->t_state != TCPS_TIME_WAIT &&
258 ticks - tp->t_rcvtime <= tcp_maxidle)
259 callout_reset_on(&tp->t_timers->tt_2msl, tcp_keepintvl,
260 tcp_timer_2msl, tp, INP_CPU(inp));
261 else
262 tp = tcp_close(tp);
263 }
264
265 #ifdef TCPDEBUG
266 if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
267 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
268 PRU_SLOWTIMO);
269 #endif
270 if (tp != NULL)
271 INP_WUNLOCK(inp);
272 INP_INFO_WUNLOCK(&V_tcbinfo);
273 CURVNET_RESTORE();
274 }
275
276 void
277 tcp_timer_keep(void *xtp)
278 {
279 struct tcpcb *tp = xtp;
280 struct tcptemp *t_template;
281 struct inpcb *inp;
282 CURVNET_SET(tp->t_vnet);
283 #ifdef TCPDEBUG
284 int ostate;
285
286 ostate = tp->t_state;
287 #endif
288 INP_INFO_WLOCK(&V_tcbinfo);
289 inp = tp->t_inpcb;
290 /*
291 * XXXRW: While this assert is in fact correct, bugs in the tcpcb
292 * tear-down mean we need it as a work-around for races between
293 * timers and tcp_discardcb().
294 *
295 * KASSERT(inp != NULL, ("tcp_timer_keep: inp == NULL"));
296 */
297 if (inp == NULL) {
298 tcp_timer_race++;
299 INP_INFO_WUNLOCK(&V_tcbinfo);
300 CURVNET_RESTORE();
301 return;
302 }
303 INP_WLOCK(inp);
304 if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_keep)
305 || !callout_active(&tp->t_timers->tt_keep)) {
306 INP_WUNLOCK(inp);
307 INP_INFO_WUNLOCK(&V_tcbinfo);
308 CURVNET_RESTORE();
309 return;
310 }
311 callout_deactivate(&tp->t_timers->tt_keep);
312 /*
313 * Keep-alive timer went off; send something
314 * or drop connection if idle for too long.
315 */
316 TCPSTAT_INC(tcps_keeptimeo);
317 if (tp->t_state < TCPS_ESTABLISHED)
318 goto dropit;
319 if ((always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) &&
320 tp->t_state <= TCPS_CLOSING) {
321 if (ticks - tp->t_rcvtime >= tcp_keepidle + tcp_maxidle)
322 goto dropit;
323 /*
324 * Send a packet designed to force a response
325 * if the peer is up and reachable:
326 * either an ACK if the connection is still alive,
327 * or an RST if the peer has closed the connection
328 * due to timeout or reboot.
329 * Using sequence number tp->snd_una-1
330 * causes the transmitted zero-length segment
331 * to lie outside the receive window;
332 * by the protocol spec, this requires the
333 * correspondent TCP to respond.
334 */
335 TCPSTAT_INC(tcps_keepprobe);
336 t_template = tcpip_maketemplate(inp);
337 if (t_template) {
338 tcp_respond(tp, t_template->tt_ipgen,
339 &t_template->tt_t, (struct mbuf *)NULL,
340 tp->rcv_nxt, tp->snd_una - 1, 0);
341 free(t_template, M_TEMP);
342 }
343 callout_reset_on(&tp->t_timers->tt_keep, tcp_keepintvl, tcp_timer_keep, tp, INP_CPU(inp));
344 } else
345 callout_reset_on(&tp->t_timers->tt_keep, tcp_keepidle, tcp_timer_keep, tp, INP_CPU(inp));
346
347 #ifdef TCPDEBUG
348 if (inp->inp_socket->so_options & SO_DEBUG)
349 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
350 PRU_SLOWTIMO);
351 #endif
352 INP_WUNLOCK(inp);
353 INP_INFO_WUNLOCK(&V_tcbinfo);
354 CURVNET_RESTORE();
355 return;
356
357 dropit:
358 TCPSTAT_INC(tcps_keepdrops);
359 tp = tcp_drop(tp, ETIMEDOUT);
360
361 #ifdef TCPDEBUG
362 if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
363 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
364 PRU_SLOWTIMO);
365 #endif
366 if (tp != NULL)
367 INP_WUNLOCK(tp->t_inpcb);
368 INP_INFO_WUNLOCK(&V_tcbinfo);
369 CURVNET_RESTORE();
370 }
371
372 void
373 tcp_timer_persist(void *xtp)
374 {
375 struct tcpcb *tp = xtp;
376 struct inpcb *inp;
377 CURVNET_SET(tp->t_vnet);
378 #ifdef TCPDEBUG
379 int ostate;
380
381 ostate = tp->t_state;
382 #endif
383 INP_INFO_WLOCK(&V_tcbinfo);
384 inp = tp->t_inpcb;
385 /*
386 * XXXRW: While this assert is in fact correct, bugs in the tcpcb
387 * tear-down mean we need it as a work-around for races between
388 * timers and tcp_discardcb().
389 *
390 * KASSERT(inp != NULL, ("tcp_timer_persist: inp == NULL"));
391 */
392 if (inp == NULL) {
393 tcp_timer_race++;
394 INP_INFO_WUNLOCK(&V_tcbinfo);
395 CURVNET_RESTORE();
396 return;
397 }
398 INP_WLOCK(inp);
399 if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_persist)
400 || !callout_active(&tp->t_timers->tt_persist)) {
401 INP_WUNLOCK(inp);
402 INP_INFO_WUNLOCK(&V_tcbinfo);
403 CURVNET_RESTORE();
404 return;
405 }
406 callout_deactivate(&tp->t_timers->tt_persist);
407 /*
408 * Persistance timer into zero window.
409 * Force a byte to be output, if possible.
410 */
411 TCPSTAT_INC(tcps_persisttimeo);
412 /*
413 * Hack: if the peer is dead/unreachable, we do not
414 * time out if the window is closed. After a full
415 * backoff, drop the connection if the idle time
416 * (no responses to probes) reaches the maximum
417 * backoff that we would use if retransmitting.
418 */
419 if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
420 (ticks - tp->t_rcvtime >= tcp_maxpersistidle ||
421 ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) {
422 TCPSTAT_INC(tcps_persistdrop);
423 tp = tcp_drop(tp, ETIMEDOUT);
424 goto out;
425 }
426 tcp_setpersist(tp);
427 tp->t_flags |= TF_FORCEDATA;
428 (void) tcp_output(tp);
429 tp->t_flags &= ~TF_FORCEDATA;
430
431 out:
432 #ifdef TCPDEBUG
433 if (tp != NULL && tp->t_inpcb->inp_socket->so_options & SO_DEBUG)
434 tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO);
435 #endif
436 if (tp != NULL)
437 INP_WUNLOCK(inp);
438 INP_INFO_WUNLOCK(&V_tcbinfo);
439 CURVNET_RESTORE();
440 }
441
442 void
443 tcp_timer_rexmt(void * xtp)
444 {
445 struct tcpcb *tp = xtp;
446 CURVNET_SET(tp->t_vnet);
447 int rexmt;
448 int headlocked;
449 struct inpcb *inp;
450 #ifdef TCPDEBUG
451 int ostate;
452
453 ostate = tp->t_state;
454 #endif
455 INP_INFO_RLOCK(&V_tcbinfo);
456 inp = tp->t_inpcb;
457 /*
458 * XXXRW: While this assert is in fact correct, bugs in the tcpcb
459 * tear-down mean we need it as a work-around for races between
460 * timers and tcp_discardcb().
461 *
462 * KASSERT(inp != NULL, ("tcp_timer_rexmt: inp == NULL"));
463 */
464 if (inp == NULL) {
465 tcp_timer_race++;
466 INP_INFO_RUNLOCK(&V_tcbinfo);
467 CURVNET_RESTORE();
468 return;
469 }
470 INP_WLOCK(inp);
471 if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_rexmt)
472 || !callout_active(&tp->t_timers->tt_rexmt)) {
473 INP_WUNLOCK(inp);
474 INP_INFO_RUNLOCK(&V_tcbinfo);
475 CURVNET_RESTORE();
476 return;
477 }
478 callout_deactivate(&tp->t_timers->tt_rexmt);
479 tcp_free_sackholes(tp);
480 /*
481 * Retransmission timer went off. Message has not
482 * been acked within retransmit interval. Back off
483 * to a longer retransmit interval and retransmit one segment.
484 */
485 if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) {
486 tp->t_rxtshift = TCP_MAXRXTSHIFT;
487 TCPSTAT_INC(tcps_timeoutdrop);
488 in_pcbref(inp);
489 INP_INFO_RUNLOCK(&V_tcbinfo);
490 INP_WUNLOCK(inp);
491 INP_INFO_WLOCK(&V_tcbinfo);
492 INP_WLOCK(inp);
493 if (in_pcbrele_wlocked(inp)) {
494 INP_INFO_WUNLOCK(&V_tcbinfo);
495 CURVNET_RESTORE();
496 return;
497 }
498 if (inp->inp_flags & INP_DROPPED) {
499 INP_WUNLOCK(inp);
500 INP_INFO_WUNLOCK(&V_tcbinfo);
501 CURVNET_RESTORE();
502 return;
503 }
504
505 tp = tcp_drop(tp, tp->t_softerror ?
506 tp->t_softerror : ETIMEDOUT);
507 headlocked = 1;
508 goto out;
509 }
510 INP_INFO_RUNLOCK(&V_tcbinfo);
511 headlocked = 0;
512 if (tp->t_rxtshift == 1) {
513 /*
514 * first retransmit; record ssthresh and cwnd so they can
515 * be recovered if this turns out to be a "bad" retransmit.
516 * A retransmit is considered "bad" if an ACK for this
517 * segment is received within RTT/2 interval; the assumption
518 * here is that the ACK was already in flight. See
519 * "On Estimating End-to-End Network Path Properties" by
520 * Allman and Paxson for more details.
521 */
522 tp->snd_cwnd_prev = tp->snd_cwnd;
523 tp->snd_ssthresh_prev = tp->snd_ssthresh;
524 tp->snd_recover_prev = tp->snd_recover;
525 if (IN_FASTRECOVERY(tp->t_flags))
526 tp->t_flags |= TF_WASFRECOVERY;
527 else
528 tp->t_flags &= ~TF_WASFRECOVERY;
529 if (IN_CONGRECOVERY(tp->t_flags))
530 tp->t_flags |= TF_WASCRECOVERY;
531 else
532 tp->t_flags &= ~TF_WASCRECOVERY;
533 tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1));
534 tp->t_flags |= TF_PREVVALID;
535 } else
536 tp->t_flags &= ~TF_PREVVALID;
537 TCPSTAT_INC(tcps_rexmttimeo);
538 if (tp->t_state == TCPS_SYN_SENT)
539 rexmt = TCP_REXMTVAL(tp) * tcp_syn_backoff[tp->t_rxtshift];
540 else
541 rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
542 TCPT_RANGESET(tp->t_rxtcur, rexmt,
543 tp->t_rttmin, TCPTV_REXMTMAX);
544 /*
545 * Disable rfc1323 if we haven't got any response to
546 * our third SYN to work-around some broken terminal servers
547 * (most of which have hopefully been retired) that have bad VJ
548 * header compression code which trashes TCP segments containing
549 * unknown-to-them TCP options.
550 */
551 if ((tp->t_state == TCPS_SYN_SENT) && (tp->t_rxtshift == 3))
552 tp->t_flags &= ~(TF_REQ_SCALE|TF_REQ_TSTMP);
553 /*
554 * If we backed off this far, our srtt estimate is probably bogus.
555 * Clobber it so we'll take the next rtt measurement as our srtt;
556 * move the current srtt into rttvar to keep the current
557 * retransmit times until then.
558 */
559 if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
560 #ifdef INET6
561 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0)
562 in6_losing(tp->t_inpcb);
563 else
564 #endif
565 tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
566 tp->t_srtt = 0;
567 }
568 tp->snd_nxt = tp->snd_una;
569 tp->snd_recover = tp->snd_max;
570 /*
571 * Force a segment to be sent.
572 */
573 tp->t_flags |= TF_ACKNOW;
574 /*
575 * If timing a segment in this window, stop the timer.
576 */
577 tp->t_rtttime = 0;
578
579 cc_cong_signal(tp, NULL, CC_RTO);
580
581 (void) tcp_output(tp);
582
583 out:
584 #ifdef TCPDEBUG
585 if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
586 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
587 PRU_SLOWTIMO);
588 #endif
589 if (tp != NULL)
590 INP_WUNLOCK(inp);
591 if (headlocked)
592 INP_INFO_WUNLOCK(&V_tcbinfo);
593 CURVNET_RESTORE();
594 }
595
596 void
597 tcp_timer_activate(struct tcpcb *tp, int timer_type, u_int delta)
598 {
599 struct callout *t_callout;
600 void *f_callout;
601 struct inpcb *inp = tp->t_inpcb;
602 int cpu = INP_CPU(inp);
603
604 switch (timer_type) {
605 case TT_DELACK:
606 t_callout = &tp->t_timers->tt_delack;
607 f_callout = tcp_timer_delack;
608 break;
609 case TT_REXMT:
610 t_callout = &tp->t_timers->tt_rexmt;
611 f_callout = tcp_timer_rexmt;
612 break;
613 case TT_PERSIST:
614 t_callout = &tp->t_timers->tt_persist;
615 f_callout = tcp_timer_persist;
616 break;
617 case TT_KEEP:
618 t_callout = &tp->t_timers->tt_keep;
619 f_callout = tcp_timer_keep;
620 break;
621 case TT_2MSL:
622 t_callout = &tp->t_timers->tt_2msl;
623 f_callout = tcp_timer_2msl;
624 break;
625 default:
626 panic("bad timer_type");
627 }
628 if (delta == 0) {
629 callout_stop(t_callout);
630 } else {
631 callout_reset_on(t_callout, delta, f_callout, tp, cpu);
632 }
633 }
634
635 int
636 tcp_timer_active(struct tcpcb *tp, int timer_type)
637 {
638 struct callout *t_callout;
639
640 switch (timer_type) {
641 case TT_DELACK:
642 t_callout = &tp->t_timers->tt_delack;
643 break;
644 case TT_REXMT:
645 t_callout = &tp->t_timers->tt_rexmt;
646 break;
647 case TT_PERSIST:
648 t_callout = &tp->t_timers->tt_persist;
649 break;
650 case TT_KEEP:
651 t_callout = &tp->t_timers->tt_keep;
652 break;
653 case TT_2MSL:
654 t_callout = &tp->t_timers->tt_2msl;
655 break;
656 default:
657 panic("bad timer_type");
658 }
659 return callout_active(t_callout);
660 }
661
662 #define ticks_to_msecs(t) (1000*(t) / hz)
663
664 void
665 tcp_timer_to_xtimer(struct tcpcb *tp, struct tcp_timer *timer, struct xtcp_timer *xtimer)
666 {
667 bzero(xtimer, sizeof(struct xtcp_timer));
668 if (timer == NULL)
669 return;
670 if (callout_active(&timer->tt_delack))
671 xtimer->tt_delack = ticks_to_msecs(timer->tt_delack.c_time - ticks);
672 if (callout_active(&timer->tt_rexmt))
673 xtimer->tt_rexmt = ticks_to_msecs(timer->tt_rexmt.c_time - ticks);
674 if (callout_active(&timer->tt_persist))
675 xtimer->tt_persist = ticks_to_msecs(timer->tt_persist.c_time - ticks);
676 if (callout_active(&timer->tt_keep))
677 xtimer->tt_keep = ticks_to_msecs(timer->tt_keep.c_time - ticks);
678 if (callout_active(&timer->tt_2msl))
679 xtimer->tt_2msl = ticks_to_msecs(timer->tt_2msl.c_time - ticks);
680 xtimer->t_rcvtime = ticks_to_msecs(ticks - tp->t_rcvtime);
681 }
Cache object: b77273905d85af21fa3a34c76715955a
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