1 | /* $NetBSD: tcp_timer.c,v 1.91 2016/07/25 00:10:38 knakahara Exp $ */ |
2 | |
3 | /* |
4 | * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. |
5 | * All rights reserved. |
6 | * |
7 | * Redistribution and use in source and binary forms, with or without |
8 | * modification, are permitted provided that the following conditions |
9 | * are met: |
10 | * 1. Redistributions of source code must retain the above copyright |
11 | * notice, this list of conditions and the following disclaimer. |
12 | * 2. Redistributions in binary form must reproduce the above copyright |
13 | * notice, this list of conditions and the following disclaimer in the |
14 | * documentation and/or other materials provided with the distribution. |
15 | * 3. Neither the name of the project nor the names of its contributors |
16 | * may be used to endorse or promote products derived from this software |
17 | * without specific prior written permission. |
18 | * |
19 | * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND |
20 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
21 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
22 | * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE |
23 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
24 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
25 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
26 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
27 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
28 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
29 | * SUCH DAMAGE. |
30 | */ |
31 | |
32 | /*- |
33 | * Copyright (c) 1997, 1998, 2001, 2005 The NetBSD Foundation, Inc. |
34 | * All rights reserved. |
35 | * |
36 | * This code is derived from software contributed to The NetBSD Foundation |
37 | * by Jason R. Thorpe and Kevin M. Lahey of the Numerical Aerospace Simulation |
38 | * Facility, NASA Ames Research Center. |
39 | * This code is derived from software contributed to The NetBSD Foundation |
40 | * by Charles M. Hannum. |
41 | * |
42 | * Redistribution and use in source and binary forms, with or without |
43 | * modification, are permitted provided that the following conditions |
44 | * are met: |
45 | * 1. Redistributions of source code must retain the above copyright |
46 | * notice, this list of conditions and the following disclaimer. |
47 | * 2. Redistributions in binary form must reproduce the above copyright |
48 | * notice, this list of conditions and the following disclaimer in the |
49 | * documentation and/or other materials provided with the distribution. |
50 | * |
51 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
52 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
53 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
54 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
55 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
56 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
57 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
58 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
59 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
60 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
61 | * POSSIBILITY OF SUCH DAMAGE. |
62 | */ |
63 | |
64 | /* |
65 | * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 |
66 | * The Regents of the University of California. All rights reserved. |
67 | * |
68 | * Redistribution and use in source and binary forms, with or without |
69 | * modification, are permitted provided that the following conditions |
70 | * are met: |
71 | * 1. Redistributions of source code must retain the above copyright |
72 | * notice, this list of conditions and the following disclaimer. |
73 | * 2. Redistributions in binary form must reproduce the above copyright |
74 | * notice, this list of conditions and the following disclaimer in the |
75 | * documentation and/or other materials provided with the distribution. |
76 | * 3. Neither the name of the University nor the names of its contributors |
77 | * may be used to endorse or promote products derived from this software |
78 | * without specific prior written permission. |
79 | * |
80 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
81 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
82 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
83 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
84 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
85 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
86 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
87 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
88 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
89 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
90 | * SUCH DAMAGE. |
91 | * |
92 | * @(#)tcp_timer.c 8.2 (Berkeley) 5/24/95 |
93 | */ |
94 | |
95 | #include <sys/cdefs.h> |
96 | __KERNEL_RCSID(0, "$NetBSD: tcp_timer.c,v 1.91 2016/07/25 00:10:38 knakahara Exp $" ); |
97 | |
98 | #ifdef _KERNEL_OPT |
99 | #include "opt_inet.h" |
100 | #include "opt_tcp_debug.h" |
101 | #endif |
102 | |
103 | #include <sys/param.h> |
104 | #include <sys/systm.h> |
105 | #include <sys/mbuf.h> |
106 | #include <sys/socket.h> |
107 | #include <sys/socketvar.h> |
108 | #include <sys/protosw.h> |
109 | #include <sys/errno.h> |
110 | #include <sys/kernel.h> |
111 | |
112 | #include <net/if.h> |
113 | |
114 | #include <netinet/in.h> |
115 | #include <netinet/in_systm.h> |
116 | #include <netinet/ip.h> |
117 | #include <netinet/in_pcb.h> |
118 | #include <netinet/ip_var.h> |
119 | #include <netinet/ip_icmp.h> |
120 | |
121 | #ifdef INET6 |
122 | #ifndef INET |
123 | #include <netinet/in.h> |
124 | #endif |
125 | #include <netinet/ip6.h> |
126 | #include <netinet6/in6_pcb.h> |
127 | #endif |
128 | |
129 | #include <netinet/tcp.h> |
130 | #include <netinet/tcp_fsm.h> |
131 | #include <netinet/tcp_seq.h> |
132 | #include <netinet/tcp_timer.h> |
133 | #include <netinet/tcp_var.h> |
134 | #include <netinet/tcp_private.h> |
135 | #include <netinet/tcp_congctl.h> |
136 | #include <netinet/tcpip.h> |
137 | #ifdef TCP_DEBUG |
138 | #include <netinet/tcp_debug.h> |
139 | #endif |
140 | |
141 | /* |
142 | * Various tunable timer parameters. These are initialized in tcp_init(), |
143 | * unless they are patched. |
144 | */ |
145 | u_int tcp_keepinit = 0; |
146 | u_int tcp_keepidle = 0; |
147 | u_int tcp_keepintvl = 0; |
148 | u_int tcp_keepcnt = 0; /* max idle probes */ |
149 | |
150 | int tcp_maxpersistidle = 0; /* max idle time in persist */ |
151 | |
152 | /* |
153 | * Time to delay the ACK. This is initialized in tcp_init(), unless |
154 | * its patched. |
155 | */ |
156 | int tcp_delack_ticks = 0; |
157 | |
158 | void tcp_timer_rexmt(void *); |
159 | void tcp_timer_persist(void *); |
160 | void tcp_timer_keep(void *); |
161 | void tcp_timer_2msl(void *); |
162 | |
163 | const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS] = { |
164 | tcp_timer_rexmt, |
165 | tcp_timer_persist, |
166 | tcp_timer_keep, |
167 | tcp_timer_2msl, |
168 | }; |
169 | |
170 | /* |
171 | * Timer state initialization, called from tcp_init(). |
172 | */ |
173 | void |
174 | tcp_timer_init(void) |
175 | { |
176 | |
177 | if (tcp_keepinit == 0) |
178 | tcp_keepinit = TCPTV_KEEP_INIT; |
179 | |
180 | if (tcp_keepidle == 0) |
181 | tcp_keepidle = TCPTV_KEEP_IDLE; |
182 | |
183 | if (tcp_keepintvl == 0) |
184 | tcp_keepintvl = TCPTV_KEEPINTVL; |
185 | |
186 | if (tcp_keepcnt == 0) |
187 | tcp_keepcnt = TCPTV_KEEPCNT; |
188 | |
189 | if (tcp_maxpersistidle == 0) |
190 | tcp_maxpersistidle = TCPTV_KEEP_IDLE; |
191 | |
192 | if (tcp_delack_ticks == 0) |
193 | tcp_delack_ticks = TCP_DELACK_TICKS; |
194 | } |
195 | |
196 | /* |
197 | * Callout to process delayed ACKs for a TCPCB. |
198 | */ |
199 | void |
200 | tcp_delack(void *arg) |
201 | { |
202 | struct tcpcb *tp = arg; |
203 | |
204 | /* |
205 | * If tcp_output() wasn't able to transmit the ACK |
206 | * for whatever reason, it will restart the delayed |
207 | * ACK callout. |
208 | */ |
209 | |
210 | mutex_enter(softnet_lock); |
211 | if ((tp->t_flags & (TF_DEAD | TF_DELACK)) != TF_DELACK) { |
212 | mutex_exit(softnet_lock); |
213 | return; |
214 | } |
215 | if (!callout_expired(&tp->t_delack_ch)) { |
216 | mutex_exit(softnet_lock); |
217 | return; |
218 | } |
219 | |
220 | tp->t_flags |= TF_ACKNOW; |
221 | KERNEL_LOCK(1, NULL); |
222 | (void) tcp_output(tp); |
223 | KERNEL_UNLOCK_ONE(NULL); |
224 | mutex_exit(softnet_lock); |
225 | } |
226 | |
227 | /* |
228 | * Tcp protocol timeout routine called every 500 ms. |
229 | * Updates the timers in all active tcb's and |
230 | * causes finite state machine actions if timers expire. |
231 | */ |
232 | void |
233 | tcp_slowtimo(void *arg) |
234 | { |
235 | |
236 | mutex_enter(softnet_lock); |
237 | tcp_iss_seq += TCP_ISSINCR; /* increment iss */ |
238 | tcp_now++; /* for timestamps */ |
239 | mutex_exit(softnet_lock); |
240 | |
241 | callout_schedule(&tcp_slowtimo_ch, hz / PR_SLOWHZ); |
242 | } |
243 | |
244 | /* |
245 | * Cancel all timers for TCP tp. |
246 | */ |
247 | void |
248 | tcp_canceltimers(struct tcpcb *tp) |
249 | { |
250 | int i; |
251 | |
252 | for (i = 0; i < TCPT_NTIMERS; i++) |
253 | TCP_TIMER_DISARM(tp, i); |
254 | } |
255 | |
256 | const int tcp_backoff[TCP_MAXRXTSHIFT + 1] = |
257 | { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 }; |
258 | |
259 | const int tcp_totbackoff = 511; /* sum of tcp_backoff[] */ |
260 | |
261 | /* |
262 | * TCP timer processing. |
263 | */ |
264 | |
265 | void |
266 | tcp_timer_rexmt(void *arg) |
267 | { |
268 | struct tcpcb *tp = arg; |
269 | uint32_t rto; |
270 | #ifdef TCP_DEBUG |
271 | struct socket *so = NULL; |
272 | short ostate; |
273 | #endif |
274 | |
275 | mutex_enter(softnet_lock); |
276 | if ((tp->t_flags & TF_DEAD) != 0) { |
277 | mutex_exit(softnet_lock); |
278 | return; |
279 | } |
280 | if (!callout_expired(&tp->t_timer[TCPT_REXMT])) { |
281 | mutex_exit(softnet_lock); |
282 | return; |
283 | } |
284 | |
285 | KERNEL_LOCK(1, NULL); |
286 | if ((tp->t_flags & TF_PMTUD_PEND) && tp->t_inpcb && |
287 | SEQ_GEQ(tp->t_pmtud_th_seq, tp->snd_una) && |
288 | SEQ_LT(tp->t_pmtud_th_seq, (int)(tp->snd_una + tp->t_ourmss))) { |
289 | extern struct sockaddr_in icmpsrc; |
290 | struct icmp icmp; |
291 | |
292 | tp->t_flags &= ~TF_PMTUD_PEND; |
293 | |
294 | /* XXX create fake icmp message with relevant entries */ |
295 | icmp.icmp_nextmtu = tp->t_pmtud_nextmtu; |
296 | icmp.icmp_ip.ip_len = tp->t_pmtud_ip_len; |
297 | icmp.icmp_ip.ip_hl = tp->t_pmtud_ip_hl; |
298 | icmpsrc.sin_addr = tp->t_inpcb->inp_faddr; |
299 | icmp_mtudisc(&icmp, icmpsrc.sin_addr); |
300 | |
301 | /* |
302 | * Notify all connections to the same peer about |
303 | * new mss and trigger retransmit. |
304 | */ |
305 | in_pcbnotifyall(&tcbtable, icmpsrc.sin_addr, EMSGSIZE, |
306 | tcp_mtudisc); |
307 | KERNEL_UNLOCK_ONE(NULL); |
308 | mutex_exit(softnet_lock); |
309 | return; |
310 | } |
311 | #ifdef TCP_DEBUG |
312 | #ifdef INET |
313 | if (tp->t_inpcb) |
314 | so = tp->t_inpcb->inp_socket; |
315 | #endif |
316 | #ifdef INET6 |
317 | if (tp->t_in6pcb) |
318 | so = tp->t_in6pcb->in6p_socket; |
319 | #endif |
320 | ostate = tp->t_state; |
321 | #endif /* TCP_DEBUG */ |
322 | |
323 | /* |
324 | * Clear the SACK scoreboard, reset FACK estimate. |
325 | */ |
326 | tcp_free_sackholes(tp); |
327 | tp->snd_fack = tp->snd_una; |
328 | |
329 | /* |
330 | * Retransmission timer went off. Message has not |
331 | * been acked within retransmit interval. Back off |
332 | * to a longer retransmit interval and retransmit one segment. |
333 | */ |
334 | |
335 | if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { |
336 | tp->t_rxtshift = TCP_MAXRXTSHIFT; |
337 | TCP_STATINC(TCP_STAT_TIMEOUTDROP); |
338 | tp = tcp_drop(tp, tp->t_softerror ? |
339 | tp->t_softerror : ETIMEDOUT); |
340 | goto out; |
341 | } |
342 | TCP_STATINC(TCP_STAT_REXMTTIMEO); |
343 | rto = TCP_REXMTVAL(tp); |
344 | if (rto < tp->t_rttmin) |
345 | rto = tp->t_rttmin; |
346 | TCPT_RANGESET(tp->t_rxtcur, rto * tcp_backoff[tp->t_rxtshift], |
347 | tp->t_rttmin, TCPTV_REXMTMAX); |
348 | TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); |
349 | |
350 | /* |
351 | * If we are losing and we are trying path MTU discovery, |
352 | * try turning it off. This will avoid black holes in |
353 | * the network which suppress or fail to send "packet |
354 | * too big" ICMP messages. We should ideally do |
355 | * lots more sophisticated searching to find the right |
356 | * value here... |
357 | */ |
358 | if (tp->t_mtudisc && tp->t_rxtshift > TCP_MAXRXTSHIFT / 6) { |
359 | TCP_STATINC(TCP_STAT_PMTUBLACKHOLE); |
360 | |
361 | #ifdef INET |
362 | /* try turning PMTUD off */ |
363 | if (tp->t_inpcb) |
364 | tp->t_mtudisc = 0; |
365 | #endif |
366 | #ifdef INET6 |
367 | /* try using IPv6 minimum MTU */ |
368 | if (tp->t_in6pcb) |
369 | tp->t_mtudisc = 0; |
370 | #endif |
371 | |
372 | /* XXX: more sophisticated Black hole recovery code? */ |
373 | } |
374 | |
375 | /* |
376 | * If losing, let the lower level know and try for |
377 | * a better route. Also, if we backed off this far, |
378 | * our srtt estimate is probably bogus. Clobber it |
379 | * so we'll take the next rtt measurement as our srtt; |
380 | * move the current srtt into rttvar to keep the current |
381 | * retransmit times until then. |
382 | */ |
383 | if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { |
384 | #ifdef INET |
385 | if (tp->t_inpcb) |
386 | in_losing(tp->t_inpcb); |
387 | #endif |
388 | #ifdef INET6 |
389 | if (tp->t_in6pcb) |
390 | in6_losing(tp->t_in6pcb); |
391 | #endif |
392 | /* |
393 | * This operation is not described in RFC2988. The |
394 | * point is to keep srtt+4*rttvar constant, so we |
395 | * should shift right 2 bits to divide by 4, and then |
396 | * shift right one bit because the storage |
397 | * representation of rttvar is 1/16s vs 1/32s for |
398 | * srtt. |
399 | */ |
400 | tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); |
401 | tp->t_srtt = 0; |
402 | } |
403 | tp->snd_nxt = tp->snd_una; |
404 | tp->snd_high = tp->snd_max; |
405 | /* |
406 | * If timing a segment in this window, stop the timer. |
407 | */ |
408 | tp->t_rtttime = 0; |
409 | /* |
410 | * Remember if we are retransmitting a SYN, because if |
411 | * we do, set the initial congestion window must be set |
412 | * to 1 segment. |
413 | */ |
414 | if (tp->t_state == TCPS_SYN_SENT) |
415 | tp->t_flags |= TF_SYN_REXMT; |
416 | |
417 | /* |
418 | * Adjust congestion control parameters. |
419 | */ |
420 | tp->t_congctl->slow_retransmit(tp); |
421 | |
422 | (void) tcp_output(tp); |
423 | |
424 | out: |
425 | #ifdef TCP_DEBUG |
426 | if (tp && so->so_options & SO_DEBUG) |
427 | tcp_trace(TA_USER, ostate, tp, NULL, |
428 | PRU_SLOWTIMO | (TCPT_REXMT << 8)); |
429 | #endif |
430 | KERNEL_UNLOCK_ONE(NULL); |
431 | mutex_exit(softnet_lock); |
432 | } |
433 | |
434 | void |
435 | tcp_timer_persist(void *arg) |
436 | { |
437 | struct tcpcb *tp = arg; |
438 | uint32_t rto; |
439 | #ifdef TCP_DEBUG |
440 | struct socket *so = NULL; |
441 | short ostate; |
442 | #endif |
443 | |
444 | mutex_enter(softnet_lock); |
445 | if ((tp->t_flags & TF_DEAD) != 0) { |
446 | mutex_exit(softnet_lock); |
447 | return; |
448 | } |
449 | if (!callout_expired(&tp->t_timer[TCPT_PERSIST])) { |
450 | mutex_exit(softnet_lock); |
451 | return; |
452 | } |
453 | |
454 | KERNEL_LOCK(1, NULL); |
455 | #ifdef TCP_DEBUG |
456 | #ifdef INET |
457 | if (tp->t_inpcb) |
458 | so = tp->t_inpcb->inp_socket; |
459 | #endif |
460 | #ifdef INET6 |
461 | if (tp->t_in6pcb) |
462 | so = tp->t_in6pcb->in6p_socket; |
463 | #endif |
464 | |
465 | ostate = tp->t_state; |
466 | #endif /* TCP_DEBUG */ |
467 | |
468 | /* |
469 | * Persistance timer into zero window. |
470 | * Force a byte to be output, if possible. |
471 | */ |
472 | |
473 | /* |
474 | * Hack: if the peer is dead/unreachable, we do not |
475 | * time out if the window is closed. After a full |
476 | * backoff, drop the connection if the idle time |
477 | * (no responses to probes) reaches the maximum |
478 | * backoff that we would use if retransmitting. |
479 | */ |
480 | rto = TCP_REXMTVAL(tp); |
481 | if (rto < tp->t_rttmin) |
482 | rto = tp->t_rttmin; |
483 | if (tp->t_rxtshift == TCP_MAXRXTSHIFT && |
484 | ((tcp_now - tp->t_rcvtime) >= tcp_maxpersistidle || |
485 | (tcp_now - tp->t_rcvtime) >= rto * tcp_totbackoff)) { |
486 | TCP_STATINC(TCP_STAT_PERSISTDROPS); |
487 | tp = tcp_drop(tp, ETIMEDOUT); |
488 | goto out; |
489 | } |
490 | TCP_STATINC(TCP_STAT_PERSISTTIMEO); |
491 | tcp_setpersist(tp); |
492 | tp->t_force = 1; |
493 | (void) tcp_output(tp); |
494 | tp->t_force = 0; |
495 | |
496 | out: |
497 | #ifdef TCP_DEBUG |
498 | if (tp && so->so_options & SO_DEBUG) |
499 | tcp_trace(TA_USER, ostate, tp, NULL, |
500 | PRU_SLOWTIMO | (TCPT_PERSIST << 8)); |
501 | #endif |
502 | KERNEL_UNLOCK_ONE(NULL); |
503 | mutex_exit(softnet_lock); |
504 | } |
505 | |
506 | void |
507 | tcp_timer_keep(void *arg) |
508 | { |
509 | struct tcpcb *tp = arg; |
510 | struct socket *so = NULL; /* Quell compiler warning */ |
511 | #ifdef TCP_DEBUG |
512 | short ostate; |
513 | #endif |
514 | |
515 | mutex_enter(softnet_lock); |
516 | if ((tp->t_flags & TF_DEAD) != 0) { |
517 | mutex_exit(softnet_lock); |
518 | return; |
519 | } |
520 | if (!callout_expired(&tp->t_timer[TCPT_KEEP])) { |
521 | mutex_exit(softnet_lock); |
522 | return; |
523 | } |
524 | |
525 | KERNEL_LOCK(1, NULL); |
526 | |
527 | #ifdef TCP_DEBUG |
528 | ostate = tp->t_state; |
529 | #endif /* TCP_DEBUG */ |
530 | |
531 | /* |
532 | * Keep-alive timer went off; send something |
533 | * or drop connection if idle for too long. |
534 | */ |
535 | |
536 | TCP_STATINC(TCP_STAT_KEEPTIMEO); |
537 | if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) |
538 | goto dropit; |
539 | #ifdef INET |
540 | if (tp->t_inpcb) |
541 | so = tp->t_inpcb->inp_socket; |
542 | #endif |
543 | #ifdef INET6 |
544 | if (tp->t_in6pcb) |
545 | so = tp->t_in6pcb->in6p_socket; |
546 | #endif |
547 | KASSERT(so != NULL); |
548 | if (so->so_options & SO_KEEPALIVE && |
549 | tp->t_state <= TCPS_CLOSE_WAIT) { |
550 | if ((tp->t_maxidle > 0) && |
551 | ((tcp_now - tp->t_rcvtime) >= |
552 | tp->t_keepidle + tp->t_maxidle)) |
553 | goto dropit; |
554 | /* |
555 | * Send a packet designed to force a response |
556 | * if the peer is up and reachable: |
557 | * either an ACK if the connection is still alive, |
558 | * or an RST if the peer has closed the connection |
559 | * due to timeout or reboot. |
560 | * Using sequence number tp->snd_una-1 |
561 | * causes the transmitted zero-length segment |
562 | * to lie outside the receive window; |
563 | * by the protocol spec, this requires the |
564 | * correspondent TCP to respond. |
565 | */ |
566 | TCP_STATINC(TCP_STAT_KEEPPROBE); |
567 | if (tcp_compat_42) { |
568 | /* |
569 | * The keepalive packet must have nonzero |
570 | * length to get a 4.2 host to respond. |
571 | */ |
572 | (void)tcp_respond(tp, tp->t_template, |
573 | NULL, NULL, tp->rcv_nxt - 1, |
574 | tp->snd_una - 1, 0); |
575 | } else { |
576 | (void)tcp_respond(tp, tp->t_template, |
577 | NULL, NULL, tp->rcv_nxt, |
578 | tp->snd_una - 1, 0); |
579 | } |
580 | TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepintvl); |
581 | } else |
582 | TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepidle); |
583 | |
584 | #ifdef TCP_DEBUG |
585 | if (tp && so->so_options & SO_DEBUG) |
586 | tcp_trace(TA_USER, ostate, tp, NULL, |
587 | PRU_SLOWTIMO | (TCPT_KEEP << 8)); |
588 | #endif |
589 | KERNEL_UNLOCK_ONE(NULL); |
590 | mutex_exit(softnet_lock); |
591 | return; |
592 | |
593 | dropit: |
594 | TCP_STATINC(TCP_STAT_KEEPDROPS); |
595 | (void) tcp_drop(tp, ETIMEDOUT); |
596 | KERNEL_UNLOCK_ONE(NULL); |
597 | mutex_exit(softnet_lock); |
598 | } |
599 | |
600 | void |
601 | tcp_timer_2msl(void *arg) |
602 | { |
603 | struct tcpcb *tp = arg; |
604 | #ifdef TCP_DEBUG |
605 | struct socket *so = NULL; |
606 | short ostate; |
607 | #endif |
608 | |
609 | mutex_enter(softnet_lock); |
610 | if ((tp->t_flags & TF_DEAD) != 0) { |
611 | mutex_exit(softnet_lock); |
612 | return; |
613 | } |
614 | if (!callout_expired(&tp->t_timer[TCPT_2MSL])) { |
615 | mutex_exit(softnet_lock); |
616 | return; |
617 | } |
618 | |
619 | /* |
620 | * 2 MSL timeout went off, clear the SACK scoreboard, reset |
621 | * the FACK estimate. |
622 | */ |
623 | KERNEL_LOCK(1, NULL); |
624 | tcp_free_sackholes(tp); |
625 | tp->snd_fack = tp->snd_una; |
626 | |
627 | #ifdef TCP_DEBUG |
628 | #ifdef INET |
629 | if (tp->t_inpcb) |
630 | so = tp->t_inpcb->inp_socket; |
631 | #endif |
632 | #ifdef INET6 |
633 | if (tp->t_in6pcb) |
634 | so = tp->t_in6pcb->in6p_socket; |
635 | #endif |
636 | |
637 | ostate = tp->t_state; |
638 | #endif /* TCP_DEBUG */ |
639 | |
640 | /* |
641 | * 2 MSL timeout in shutdown went off. If we're closed but |
642 | * still waiting for peer to close and connection has been idle |
643 | * too long, or if 2MSL time is up from TIME_WAIT, delete connection |
644 | * control block. Otherwise, check again in a bit. |
645 | */ |
646 | if (tp->t_state != TCPS_TIME_WAIT && |
647 | ((tp->t_maxidle == 0) || |
648 | ((tcp_now - tp->t_rcvtime) <= tp->t_maxidle))) |
649 | TCP_TIMER_ARM(tp, TCPT_2MSL, tp->t_keepintvl); |
650 | else |
651 | tp = tcp_close(tp); |
652 | |
653 | #ifdef TCP_DEBUG |
654 | if (tp && so->so_options & SO_DEBUG) |
655 | tcp_trace(TA_USER, ostate, tp, NULL, |
656 | PRU_SLOWTIMO | (TCPT_2MSL << 8)); |
657 | #endif |
658 | KERNEL_UNLOCK_ONE(NULL); |
659 | mutex_exit(softnet_lock); |
660 | } |
661 | |