tcp_timer.c revision 1.80
1 /* $NetBSD: tcp_timer.c,v 1.80 2008/04/24 11:38:38 ad 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 * 3. All advertising materials mentioning features or use of this software 51 * must display the following acknowledgement: 52 * This product includes software developed by the NetBSD 53 * Foundation, Inc. and its contributors. 54 * 4. Neither the name of The NetBSD Foundation nor the names of its 55 * contributors may be used to endorse or promote products derived 56 * from this software without specific prior written permission. 57 * 58 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 59 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 60 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 61 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 62 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 63 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 64 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 65 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 66 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 67 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 68 * POSSIBILITY OF SUCH DAMAGE. 69 */ 70 71 /* 72 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 73 * The Regents of the University of California. All rights reserved. 74 * 75 * Redistribution and use in source and binary forms, with or without 76 * modification, are permitted provided that the following conditions 77 * are met: 78 * 1. Redistributions of source code must retain the above copyright 79 * notice, this list of conditions and the following disclaimer. 80 * 2. Redistributions in binary form must reproduce the above copyright 81 * notice, this list of conditions and the following disclaimer in the 82 * documentation and/or other materials provided with the distribution. 83 * 3. Neither the name of the University nor the names of its contributors 84 * may be used to endorse or promote products derived from this software 85 * without specific prior written permission. 86 * 87 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 88 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 89 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 90 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 91 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 92 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 93 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 94 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 95 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 96 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 97 * SUCH DAMAGE. 98 * 99 * @(#)tcp_timer.c 8.2 (Berkeley) 5/24/95 100 */ 101 102 #include <sys/cdefs.h> 103 __KERNEL_RCSID(0, "$NetBSD: tcp_timer.c,v 1.80 2008/04/24 11:38:38 ad Exp $"); 104 105 #include "opt_inet.h" 106 #include "opt_tcp_debug.h" 107 108 #include <sys/param.h> 109 #include <sys/systm.h> 110 #include <sys/malloc.h> 111 #include <sys/mbuf.h> 112 #include <sys/socket.h> 113 #include <sys/socketvar.h> 114 #include <sys/protosw.h> 115 #include <sys/errno.h> 116 #include <sys/kernel.h> 117 118 #include <net/if.h> 119 #include <net/route.h> 120 121 #include <netinet/in.h> 122 #include <netinet/in_systm.h> 123 #include <netinet/ip.h> 124 #include <netinet/in_pcb.h> 125 #include <netinet/ip_var.h> 126 #include <netinet/ip_icmp.h> 127 128 #ifdef INET6 129 #ifndef INET 130 #include <netinet/in.h> 131 #endif 132 #include <netinet/ip6.h> 133 #include <netinet6/in6_pcb.h> 134 #endif 135 136 #include <netinet/tcp.h> 137 #include <netinet/tcp_fsm.h> 138 #include <netinet/tcp_seq.h> 139 #include <netinet/tcp_timer.h> 140 #include <netinet/tcp_var.h> 141 #include <netinet/tcp_private.h> 142 #include <netinet/tcp_congctl.h> 143 #include <netinet/tcpip.h> 144 #ifdef TCP_DEBUG 145 #include <netinet/tcp_debug.h> 146 #endif 147 148 /* 149 * Various tunable timer parameters. These are initialized in tcp_init(), 150 * unless they are patched. 151 */ 152 u_int tcp_keepinit = 0; 153 u_int tcp_keepidle = 0; 154 u_int tcp_keepintvl = 0; 155 u_int tcp_keepcnt = 0; /* max idle probes */ 156 157 int tcp_maxpersistidle = 0; /* max idle time in persist */ 158 159 /* 160 * Time to delay the ACK. This is initialized in tcp_init(), unless 161 * its patched. 162 */ 163 int tcp_delack_ticks = 0; 164 165 void tcp_timer_rexmt(void *); 166 void tcp_timer_persist(void *); 167 void tcp_timer_keep(void *); 168 void tcp_timer_2msl(void *); 169 170 const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS] = { 171 tcp_timer_rexmt, 172 tcp_timer_persist, 173 tcp_timer_keep, 174 tcp_timer_2msl, 175 }; 176 177 /* 178 * Timer state initialization, called from tcp_init(). 179 */ 180 void 181 tcp_timer_init(void) 182 { 183 184 if (tcp_keepinit == 0) 185 tcp_keepinit = TCPTV_KEEP_INIT; 186 187 if (tcp_keepidle == 0) 188 tcp_keepidle = TCPTV_KEEP_IDLE; 189 190 if (tcp_keepintvl == 0) 191 tcp_keepintvl = TCPTV_KEEPINTVL; 192 193 if (tcp_keepcnt == 0) 194 tcp_keepcnt = TCPTV_KEEPCNT; 195 196 if (tcp_maxpersistidle == 0) 197 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 198 199 if (tcp_delack_ticks == 0) 200 tcp_delack_ticks = TCP_DELACK_TICKS; 201 } 202 203 /* 204 * Callout to process delayed ACKs for a TCPCB. 205 */ 206 void 207 tcp_delack(void *arg) 208 { 209 struct tcpcb *tp = arg; 210 211 /* 212 * If tcp_output() wasn't able to transmit the ACK 213 * for whatever reason, it will restart the delayed 214 * ACK callout. 215 */ 216 217 mutex_enter(softnet_lock); 218 if ((tp->t_flags & TF_DEAD) != 0) { 219 mutex_exit(softnet_lock); 220 return; 221 } 222 223 tp->t_flags |= TF_ACKNOW; 224 KERNEL_LOCK(1, NULL); 225 (void) tcp_output(tp); 226 KERNEL_UNLOCK_ONE(NULL); 227 mutex_exit(softnet_lock); 228 } 229 230 /* 231 * Tcp protocol timeout routine called every 500 ms. 232 * Updates the timers in all active tcb's and 233 * causes finite state machine actions if timers expire. 234 */ 235 void 236 tcp_slowtimo(void) 237 { 238 239 mutex_enter(softnet_lock); 240 tcp_iss_seq += TCP_ISSINCR; /* increment iss */ 241 tcp_now++; /* for timestamps */ 242 mutex_exit(softnet_lock); 243 } 244 245 /* 246 * Cancel all timers for TCP tp. 247 */ 248 void 249 tcp_canceltimers(struct tcpcb *tp) 250 { 251 int i; 252 253 for (i = 0; i < TCPT_NTIMERS; i++) 254 TCP_TIMER_DISARM(tp, i); 255 } 256 257 const int tcp_backoff[TCP_MAXRXTSHIFT + 1] = 258 { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 }; 259 260 const int tcp_totbackoff = 511; /* sum of tcp_backoff[] */ 261 262 /* 263 * TCP timer processing. 264 */ 265 266 void 267 tcp_timer_rexmt(void *arg) 268 { 269 struct tcpcb *tp = arg; 270 uint32_t rto; 271 #ifdef TCP_DEBUG 272 struct socket *so = NULL; 273 short ostate; 274 #endif 275 276 mutex_enter(softnet_lock); 277 if ((tp->t_flags & TF_DEAD) != 0) { 278 mutex_exit(softnet_lock); 279 return; 280 } 281 282 KERNEL_LOCK(1, NULL); 283 if ((tp->t_flags & TF_PMTUD_PEND) && tp->t_inpcb && 284 SEQ_GEQ(tp->t_pmtud_th_seq, tp->snd_una) && 285 SEQ_LT(tp->t_pmtud_th_seq, (int)(tp->snd_una + tp->t_ourmss))) { 286 extern struct sockaddr_in icmpsrc; 287 struct icmp icmp; 288 289 tp->t_flags &= ~TF_PMTUD_PEND; 290 291 /* XXX create fake icmp message with relevant entries */ 292 icmp.icmp_nextmtu = tp->t_pmtud_nextmtu; 293 icmp.icmp_ip.ip_len = tp->t_pmtud_ip_len; 294 icmp.icmp_ip.ip_hl = tp->t_pmtud_ip_hl; 295 icmpsrc.sin_addr = tp->t_inpcb->inp_faddr; 296 icmp_mtudisc(&icmp, icmpsrc.sin_addr); 297 298 /* 299 * Notify all connections to the same peer about 300 * new mss and trigger retransmit. 301 */ 302 in_pcbnotifyall(&tcbtable, icmpsrc.sin_addr, EMSGSIZE, 303 tcp_mtudisc); 304 KERNEL_UNLOCK_ONE(NULL); 305 mutex_exit(softnet_lock); 306 return; 307 } 308 #ifdef TCP_DEBUG 309 #ifdef INET 310 if (tp->t_inpcb) 311 so = tp->t_inpcb->inp_socket; 312 #endif 313 #ifdef INET6 314 if (tp->t_in6pcb) 315 so = tp->t_in6pcb->in6p_socket; 316 #endif 317 ostate = tp->t_state; 318 #endif /* TCP_DEBUG */ 319 320 /* 321 * Clear the SACK scoreboard, reset FACK estimate. 322 */ 323 tcp_free_sackholes(tp); 324 tp->snd_fack = tp->snd_una; 325 326 /* 327 * Retransmission timer went off. Message has not 328 * been acked within retransmit interval. Back off 329 * to a longer retransmit interval and retransmit one segment. 330 */ 331 332 if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { 333 tp->t_rxtshift = TCP_MAXRXTSHIFT; 334 TCP_STATINC(TCP_STAT_TIMEOUTDROP); 335 tp = tcp_drop(tp, tp->t_softerror ? 336 tp->t_softerror : ETIMEDOUT); 337 goto out; 338 } 339 TCP_STATINC(TCP_STAT_REXMTTIMEO); 340 rto = TCP_REXMTVAL(tp); 341 if (rto < tp->t_rttmin) 342 rto = tp->t_rttmin; 343 TCPT_RANGESET(tp->t_rxtcur, rto * tcp_backoff[tp->t_rxtshift], 344 tp->t_rttmin, TCPTV_REXMTMAX); 345 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 346 347 /* 348 * If we are losing and we are trying path MTU discovery, 349 * try turning it off. This will avoid black holes in 350 * the network which suppress or fail to send "packet 351 * too big" ICMP messages. We should ideally do 352 * lots more sophisticated searching to find the right 353 * value here... 354 */ 355 if (tp->t_mtudisc && tp->t_rxtshift > TCP_MAXRXTSHIFT / 6) { 356 TCP_STATINC(TCP_STAT_PMTUBLACKHOLE); 357 358 #ifdef INET 359 /* try turning PMTUD off */ 360 if (tp->t_inpcb) 361 tp->t_mtudisc = 0; 362 #endif 363 #ifdef INET6 364 /* try using IPv6 minimum MTU */ 365 if (tp->t_in6pcb) 366 tp->t_mtudisc = 0; 367 #endif 368 369 /* XXX: more sophisticated Black hole recovery code? */ 370 } 371 372 /* 373 * If losing, let the lower level know and try for 374 * a better route. Also, if we backed off this far, 375 * our srtt estimate is probably bogus. Clobber it 376 * so we'll take the next rtt measurement as our srtt; 377 * move the current srtt into rttvar to keep the current 378 * retransmit times until then. 379 */ 380 if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { 381 #ifdef INET 382 if (tp->t_inpcb) 383 in_losing(tp->t_inpcb); 384 #endif 385 #ifdef INET6 386 if (tp->t_in6pcb) 387 in6_losing(tp->t_in6pcb); 388 #endif 389 tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); 390 tp->t_srtt = 0; 391 } 392 tp->snd_nxt = tp->snd_una; 393 tp->snd_high = tp->snd_max; 394 /* 395 * If timing a segment in this window, stop the timer. 396 */ 397 tp->t_rtttime = 0; 398 /* 399 * Remember if we are retransmitting a SYN, because if 400 * we do, set the initial congestion window must be set 401 * to 1 segment. 402 */ 403 if (tp->t_state == TCPS_SYN_SENT) 404 tp->t_flags |= TF_SYN_REXMT; 405 406 /* 407 * Adjust congestion control parameters. 408 */ 409 tp->t_congctl->slow_retransmit(tp); 410 411 (void) tcp_output(tp); 412 413 out: 414 #ifdef TCP_DEBUG 415 if (tp && so->so_options & SO_DEBUG) 416 tcp_trace(TA_USER, ostate, tp, NULL, 417 PRU_SLOWTIMO | (TCPT_REXMT << 8)); 418 #endif 419 KERNEL_UNLOCK_ONE(NULL); 420 mutex_exit(softnet_lock); 421 } 422 423 void 424 tcp_timer_persist(void *arg) 425 { 426 struct tcpcb *tp = arg; 427 uint32_t rto; 428 #ifdef TCP_DEBUG 429 struct socket *so = NULL; 430 short ostate; 431 #endif 432 433 mutex_enter(softnet_lock); 434 if ((tp->t_flags & TF_DEAD) != 0) { 435 mutex_exit(softnet_lock); 436 return; 437 } 438 439 KERNEL_LOCK(1, NULL); 440 #ifdef TCP_DEBUG 441 #ifdef INET 442 if (tp->t_inpcb) 443 so = tp->t_inpcb->inp_socket; 444 #endif 445 #ifdef INET6 446 if (tp->t_in6pcb) 447 so = tp->t_in6pcb->in6p_socket; 448 #endif 449 450 ostate = tp->t_state; 451 #endif /* TCP_DEBUG */ 452 453 /* 454 * Persistance timer into zero window. 455 * Force a byte to be output, if possible. 456 */ 457 458 /* 459 * Hack: if the peer is dead/unreachable, we do not 460 * time out if the window is closed. After a full 461 * backoff, drop the connection if the idle time 462 * (no responses to probes) reaches the maximum 463 * backoff that we would use if retransmitting. 464 */ 465 rto = TCP_REXMTVAL(tp); 466 if (rto < tp->t_rttmin) 467 rto = tp->t_rttmin; 468 if (tp->t_rxtshift == TCP_MAXRXTSHIFT && 469 ((tcp_now - tp->t_rcvtime) >= tcp_maxpersistidle || 470 (tcp_now - tp->t_rcvtime) >= rto * tcp_totbackoff)) { 471 TCP_STATINC(TCP_STAT_PERSISTDROPS); 472 tp = tcp_drop(tp, ETIMEDOUT); 473 goto out; 474 } 475 TCP_STATINC(TCP_STAT_PERSISTTIMEO); 476 tcp_setpersist(tp); 477 tp->t_force = 1; 478 (void) tcp_output(tp); 479 tp->t_force = 0; 480 481 out: 482 #ifdef TCP_DEBUG 483 if (tp && so->so_options & SO_DEBUG) 484 tcp_trace(TA_USER, ostate, tp, NULL, 485 PRU_SLOWTIMO | (TCPT_PERSIST << 8)); 486 #endif 487 KERNEL_UNLOCK_ONE(NULL); 488 mutex_exit(softnet_lock); 489 } 490 491 void 492 tcp_timer_keep(void *arg) 493 { 494 struct tcpcb *tp = arg; 495 struct socket *so = NULL; /* Quell compiler warning */ 496 #ifdef TCP_DEBUG 497 short ostate; 498 #endif 499 500 mutex_enter(softnet_lock); 501 if ((tp->t_flags & TF_DEAD) != 0) { 502 mutex_exit(softnet_lock); 503 return; 504 } 505 506 KERNEL_LOCK(1, NULL); 507 508 #ifdef TCP_DEBUG 509 ostate = tp->t_state; 510 #endif /* TCP_DEBUG */ 511 512 /* 513 * Keep-alive timer went off; send something 514 * or drop connection if idle for too long. 515 */ 516 517 TCP_STATINC(TCP_STAT_KEEPTIMEO); 518 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 519 goto dropit; 520 #ifdef INET 521 if (tp->t_inpcb) 522 so = tp->t_inpcb->inp_socket; 523 #endif 524 #ifdef INET6 525 if (tp->t_in6pcb) 526 so = tp->t_in6pcb->in6p_socket; 527 #endif 528 KASSERT(so != NULL); 529 if (so->so_options & SO_KEEPALIVE && 530 tp->t_state <= TCPS_CLOSE_WAIT) { 531 if ((tp->t_maxidle > 0) && 532 ((tcp_now - tp->t_rcvtime) >= 533 tp->t_keepidle + tp->t_maxidle)) 534 goto dropit; 535 /* 536 * Send a packet designed to force a response 537 * if the peer is up and reachable: 538 * either an ACK if the connection is still alive, 539 * or an RST if the peer has closed the connection 540 * due to timeout or reboot. 541 * Using sequence number tp->snd_una-1 542 * causes the transmitted zero-length segment 543 * to lie outside the receive window; 544 * by the protocol spec, this requires the 545 * correspondent TCP to respond. 546 */ 547 TCP_STATINC(TCP_STAT_KEEPPROBE); 548 if (tcp_compat_42) { 549 /* 550 * The keepalive packet must have nonzero 551 * length to get a 4.2 host to respond. 552 */ 553 (void)tcp_respond(tp, tp->t_template, 554 (struct mbuf *)NULL, NULL, tp->rcv_nxt - 1, 555 tp->snd_una - 1, 0); 556 } else { 557 (void)tcp_respond(tp, tp->t_template, 558 (struct mbuf *)NULL, NULL, tp->rcv_nxt, 559 tp->snd_una - 1, 0); 560 } 561 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepintvl); 562 } else 563 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepidle); 564 565 #ifdef TCP_DEBUG 566 if (tp && so->so_options & SO_DEBUG) 567 tcp_trace(TA_USER, ostate, tp, NULL, 568 PRU_SLOWTIMO | (TCPT_KEEP << 8)); 569 #endif 570 KERNEL_UNLOCK_ONE(NULL); 571 mutex_exit(softnet_lock); 572 return; 573 574 dropit: 575 TCP_STATINC(TCP_STAT_KEEPDROPS); 576 (void) tcp_drop(tp, ETIMEDOUT); 577 KERNEL_UNLOCK_ONE(NULL); 578 mutex_exit(softnet_lock); 579 } 580 581 void 582 tcp_timer_2msl(void *arg) 583 { 584 struct tcpcb *tp = arg; 585 #ifdef TCP_DEBUG 586 struct socket *so = NULL; 587 short ostate; 588 #endif 589 590 mutex_enter(softnet_lock); 591 if ((tp->t_flags & TF_DEAD) != 0) { 592 mutex_exit(softnet_lock); 593 return; 594 } 595 596 /* 597 * 2 MSL timeout went off, clear the SACK scoreboard, reset 598 * the FACK estimate. 599 */ 600 KERNEL_LOCK(1, NULL); 601 tcp_free_sackholes(tp); 602 tp->snd_fack = tp->snd_una; 603 604 #ifdef TCP_DEBUG 605 #ifdef INET 606 if (tp->t_inpcb) 607 so = tp->t_inpcb->inp_socket; 608 #endif 609 #ifdef INET6 610 if (tp->t_in6pcb) 611 so = tp->t_in6pcb->in6p_socket; 612 #endif 613 614 ostate = tp->t_state; 615 #endif /* TCP_DEBUG */ 616 617 /* 618 * 2 MSL timeout in shutdown went off. If we're closed but 619 * still waiting for peer to close and connection has been idle 620 * too long, or if 2MSL time is up from TIME_WAIT, delete connection 621 * control block. Otherwise, check again in a bit. 622 */ 623 if (tp->t_state != TCPS_TIME_WAIT && 624 ((tp->t_maxidle == 0) || 625 ((tcp_now - tp->t_rcvtime) <= tp->t_maxidle))) 626 TCP_TIMER_ARM(tp, TCPT_2MSL, tp->t_keepintvl); 627 else 628 tp = tcp_close(tp); 629 630 #ifdef TCP_DEBUG 631 if (tp && so->so_options & SO_DEBUG) 632 tcp_trace(TA_USER, ostate, tp, NULL, 633 PRU_SLOWTIMO | (TCPT_2MSL << 8)); 634 #endif 635 mutex_exit(softnet_lock); 636 KERNEL_UNLOCK_ONE(NULL); 637 } 638
Indexes created Tue Sep 23 07:09:52 GMT 2025