tcp_timer.c revision 1.85
1 /* $NetBSD: tcp_timer.c,v 1.85 2011/04/20 13:35:52 gdt 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 1.85 2011/04/20 13:35:52 gdt Exp $"); 97 98 #include "opt_inet.h" 99 #include "opt_tcp_debug.h" 100 101 #include <sys/param.h> 102 #include <sys/systm.h> 103 #include <sys/malloc.h> 104 #include <sys/mbuf.h> 105 #include <sys/socket.h> 106 #include <sys/socketvar.h> 107 #include <sys/protosw.h> 108 #include <sys/errno.h> 109 #include <sys/kernel.h> 110 111 #include <net/if.h> 112 #include <net/route.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) 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 } 241 242 /* 243 * Cancel all timers for TCP tp. 244 */ 245 void 246 tcp_canceltimers(struct tcpcb *tp) 247 { 248 int i; 249 250 for (i = 0; i < TCPT_NTIMERS; i++) 251 TCP_TIMER_DISARM(tp, i); 252 } 253 254 const int tcp_backoff[TCP_MAXRXTSHIFT + 1] = 255 { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 }; 256 257 const int tcp_totbackoff = 511; /* sum of tcp_backoff[] */ 258 259 /* 260 * TCP timer processing. 261 */ 262 263 void 264 tcp_timer_rexmt(void *arg) 265 { 266 struct tcpcb *tp = arg; 267 uint32_t rto; 268 #ifdef TCP_DEBUG 269 struct socket *so = NULL; 270 short ostate; 271 #endif 272 273 mutex_enter(softnet_lock); 274 if ((tp->t_flags & TF_DEAD) != 0) { 275 mutex_exit(softnet_lock); 276 return; 277 } 278 if (!callout_expired(&tp->t_timer[TCPT_REXMT])) { 279 mutex_exit(softnet_lock); 280 return; 281 } 282 283 KERNEL_LOCK(1, NULL); 284 if ((tp->t_flags & TF_PMTUD_PEND) && tp->t_inpcb && 285 SEQ_GEQ(tp->t_pmtud_th_seq, tp->snd_una) && 286 SEQ_LT(tp->t_pmtud_th_seq, (int)(tp->snd_una + tp->t_ourmss))) { 287 extern struct sockaddr_in icmpsrc; 288 struct icmp icmp; 289 290 tp->t_flags &= ~TF_PMTUD_PEND; 291 292 /* XXX create fake icmp message with relevant entries */ 293 icmp.icmp_nextmtu = tp->t_pmtud_nextmtu; 294 icmp.icmp_ip.ip_len = tp->t_pmtud_ip_len; 295 icmp.icmp_ip.ip_hl = tp->t_pmtud_ip_hl; 296 icmpsrc.sin_addr = tp->t_inpcb->inp_faddr; 297 icmp_mtudisc(&icmp, icmpsrc.sin_addr); 298 299 /* 300 * Notify all connections to the same peer about 301 * new mss and trigger retransmit. 302 */ 303 in_pcbnotifyall(&tcbtable, icmpsrc.sin_addr, EMSGSIZE, 304 tcp_mtudisc); 305 KERNEL_UNLOCK_ONE(NULL); 306 mutex_exit(softnet_lock); 307 return; 308 } 309 #ifdef TCP_DEBUG 310 #ifdef INET 311 if (tp->t_inpcb) 312 so = tp->t_inpcb->inp_socket; 313 #endif 314 #ifdef INET6 315 if (tp->t_in6pcb) 316 so = tp->t_in6pcb->in6p_socket; 317 #endif 318 ostate = tp->t_state; 319 #endif /* TCP_DEBUG */ 320 321 /* 322 * Clear the SACK scoreboard, reset FACK estimate. 323 */ 324 tcp_free_sackholes(tp); 325 tp->snd_fack = tp->snd_una; 326 327 /* 328 * Retransmission timer went off. Message has not 329 * been acked within retransmit interval. Back off 330 * to a longer retransmit interval and retransmit one segment. 331 */ 332 333 if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { 334 tp->t_rxtshift = TCP_MAXRXTSHIFT; 335 TCP_STATINC(TCP_STAT_TIMEOUTDROP); 336 tp = tcp_drop(tp, tp->t_softerror ? 337 tp->t_softerror : ETIMEDOUT); 338 goto out; 339 } 340 TCP_STATINC(TCP_STAT_REXMTTIMEO); 341 rto = TCP_REXMTVAL(tp); 342 if (rto < tp->t_rttmin) 343 rto = tp->t_rttmin; 344 TCPT_RANGESET(tp->t_rxtcur, rto * tcp_backoff[tp->t_rxtshift], 345 tp->t_rttmin, TCPTV_REXMTMAX); 346 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 347 348 /* 349 * If we are losing and we are trying path MTU discovery, 350 * try turning it off. This will avoid black holes in 351 * the network which suppress or fail to send "packet 352 * too big" ICMP messages. We should ideally do 353 * lots more sophisticated searching to find the right 354 * value here... 355 */ 356 if (tp->t_mtudisc && tp->t_rxtshift > TCP_MAXRXTSHIFT / 6) { 357 TCP_STATINC(TCP_STAT_PMTUBLACKHOLE); 358 359 #ifdef INET 360 /* try turning PMTUD off */ 361 if (tp->t_inpcb) 362 tp->t_mtudisc = 0; 363 #endif 364 #ifdef INET6 365 /* try using IPv6 minimum MTU */ 366 if (tp->t_in6pcb) 367 tp->t_mtudisc = 0; 368 #endif 369 370 /* XXX: more sophisticated Black hole recovery code? */ 371 } 372 373 /* 374 * If losing, let the lower level know and try for 375 * a better route. Also, if we backed off this far, 376 * our srtt estimate is probably bogus. Clobber it 377 * so we'll take the next rtt measurement as our srtt; 378 * move the current srtt into rttvar to keep the current 379 * retransmit times until then. 380 */ 381 if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { 382 #ifdef INET 383 if (tp->t_inpcb) 384 in_losing(tp->t_inpcb); 385 #endif 386 #ifdef INET6 387 if (tp->t_in6pcb) 388 in6_losing(tp->t_in6pcb); 389 #endif 390 /* 391 * This operation is not described in RFC2988. The 392 * point is to keep srtt+4*rttvar constant, so we 393 * should shift right 2 bits to divide by 4, and then 394 * shift right one bit because the storage 395 * representation of rttvar is 1/16s vs 1/32s for 396 * srtt. 397 */ 398 tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); 399 tp->t_srtt = 0; 400 } 401 tp->snd_nxt = tp->snd_una; 402 tp->snd_high = tp->snd_max; 403 /* 404 * If timing a segment in this window, stop the timer. 405 */ 406 tp->t_rtttime = 0; 407 /* 408 * Remember if we are retransmitting a SYN, because if 409 * we do, set the initial congestion window must be set 410 * to 1 segment. 411 */ 412 if (tp->t_state == TCPS_SYN_SENT) 413 tp->t_flags |= TF_SYN_REXMT; 414 415 /* 416 * Adjust congestion control parameters. 417 */ 418 tp->t_congctl->slow_retransmit(tp); 419 420 (void) tcp_output(tp); 421 422 out: 423 #ifdef TCP_DEBUG 424 if (tp && so->so_options & SO_DEBUG) 425 tcp_trace(TA_USER, ostate, tp, NULL, 426 PRU_SLOWTIMO | (TCPT_REXMT << 8)); 427 #endif 428 KERNEL_UNLOCK_ONE(NULL); 429 mutex_exit(softnet_lock); 430 } 431 432 void 433 tcp_timer_persist(void *arg) 434 { 435 struct tcpcb *tp = arg; 436 uint32_t rto; 437 #ifdef TCP_DEBUG 438 struct socket *so = NULL; 439 short ostate; 440 #endif 441 442 mutex_enter(softnet_lock); 443 if ((tp->t_flags & TF_DEAD) != 0) { 444 mutex_exit(softnet_lock); 445 return; 446 } 447 if (!callout_expired(&tp->t_timer[TCPT_PERSIST])) { 448 mutex_exit(softnet_lock); 449 return; 450 } 451 452 KERNEL_LOCK(1, NULL); 453 #ifdef TCP_DEBUG 454 #ifdef INET 455 if (tp->t_inpcb) 456 so = tp->t_inpcb->inp_socket; 457 #endif 458 #ifdef INET6 459 if (tp->t_in6pcb) 460 so = tp->t_in6pcb->in6p_socket; 461 #endif 462 463 ostate = tp->t_state; 464 #endif /* TCP_DEBUG */ 465 466 /* 467 * Persistance timer into zero window. 468 * Force a byte to be output, if possible. 469 */ 470 471 /* 472 * Hack: if the peer is dead/unreachable, we do not 473 * time out if the window is closed. After a full 474 * backoff, drop the connection if the idle time 475 * (no responses to probes) reaches the maximum 476 * backoff that we would use if retransmitting. 477 */ 478 rto = TCP_REXMTVAL(tp); 479 if (rto < tp->t_rttmin) 480 rto = tp->t_rttmin; 481 if (tp->t_rxtshift == TCP_MAXRXTSHIFT && 482 ((tcp_now - tp->t_rcvtime) >= tcp_maxpersistidle || 483 (tcp_now - tp->t_rcvtime) >= rto * tcp_totbackoff)) { 484 TCP_STATINC(TCP_STAT_PERSISTDROPS); 485 tp = tcp_drop(tp, ETIMEDOUT); 486 goto out; 487 } 488 TCP_STATINC(TCP_STAT_PERSISTTIMEO); 489 tcp_setpersist(tp); 490 tp->t_force = 1; 491 (void) tcp_output(tp); 492 tp->t_force = 0; 493 494 out: 495 #ifdef TCP_DEBUG 496 if (tp && so->so_options & SO_DEBUG) 497 tcp_trace(TA_USER, ostate, tp, NULL, 498 PRU_SLOWTIMO | (TCPT_PERSIST << 8)); 499 #endif 500 KERNEL_UNLOCK_ONE(NULL); 501 mutex_exit(softnet_lock); 502 } 503 504 void 505 tcp_timer_keep(void *arg) 506 { 507 struct tcpcb *tp = arg; 508 struct socket *so = NULL; /* Quell compiler warning */ 509 #ifdef TCP_DEBUG 510 short ostate; 511 #endif 512 513 mutex_enter(softnet_lock); 514 if ((tp->t_flags & TF_DEAD) != 0) { 515 mutex_exit(softnet_lock); 516 return; 517 } 518 if (!callout_expired(&tp->t_timer[TCPT_KEEP])) { 519 mutex_exit(softnet_lock); 520 return; 521 } 522 523 KERNEL_LOCK(1, NULL); 524 525 #ifdef TCP_DEBUG 526 ostate = tp->t_state; 527 #endif /* TCP_DEBUG */ 528 529 /* 530 * Keep-alive timer went off; send something 531 * or drop connection if idle for too long. 532 */ 533 534 TCP_STATINC(TCP_STAT_KEEPTIMEO); 535 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 536 goto dropit; 537 #ifdef INET 538 if (tp->t_inpcb) 539 so = tp->t_inpcb->inp_socket; 540 #endif 541 #ifdef INET6 542 if (tp->t_in6pcb) 543 so = tp->t_in6pcb->in6p_socket; 544 #endif 545 KASSERT(so != NULL); 546 if (so->so_options & SO_KEEPALIVE && 547 tp->t_state <= TCPS_CLOSE_WAIT) { 548 if ((tp->t_maxidle > 0) && 549 ((tcp_now - tp->t_rcvtime) >= 550 tp->t_keepidle + tp->t_maxidle)) 551 goto dropit; 552 /* 553 * Send a packet designed to force a response 554 * if the peer is up and reachable: 555 * either an ACK if the connection is still alive, 556 * or an RST if the peer has closed the connection 557 * due to timeout or reboot. 558 * Using sequence number tp->snd_una-1 559 * causes the transmitted zero-length segment 560 * to lie outside the receive window; 561 * by the protocol spec, this requires the 562 * correspondent TCP to respond. 563 */ 564 TCP_STATINC(TCP_STAT_KEEPPROBE); 565 if (tcp_compat_42) { 566 /* 567 * The keepalive packet must have nonzero 568 * length to get a 4.2 host to respond. 569 */ 570 (void)tcp_respond(tp, tp->t_template, 571 (struct mbuf *)NULL, NULL, tp->rcv_nxt - 1, 572 tp->snd_una - 1, 0); 573 } else { 574 (void)tcp_respond(tp, tp->t_template, 575 (struct mbuf *)NULL, NULL, tp->rcv_nxt, 576 tp->snd_una - 1, 0); 577 } 578 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepintvl); 579 } else 580 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepidle); 581 582 #ifdef TCP_DEBUG 583 if (tp && so->so_options & SO_DEBUG) 584 tcp_trace(TA_USER, ostate, tp, NULL, 585 PRU_SLOWTIMO | (TCPT_KEEP << 8)); 586 #endif 587 KERNEL_UNLOCK_ONE(NULL); 588 mutex_exit(softnet_lock); 589 return; 590 591 dropit: 592 TCP_STATINC(TCP_STAT_KEEPDROPS); 593 (void) tcp_drop(tp, ETIMEDOUT); 594 KERNEL_UNLOCK_ONE(NULL); 595 mutex_exit(softnet_lock); 596 } 597 598 void 599 tcp_timer_2msl(void *arg) 600 { 601 struct tcpcb *tp = arg; 602 #ifdef TCP_DEBUG 603 struct socket *so = NULL; 604 short ostate; 605 #endif 606 607 mutex_enter(softnet_lock); 608 if ((tp->t_flags & TF_DEAD) != 0) { 609 mutex_exit(softnet_lock); 610 return; 611 } 612 if (!callout_expired(&tp->t_timer[TCPT_2MSL])) { 613 mutex_exit(softnet_lock); 614 return; 615 } 616 617 /* 618 * 2 MSL timeout went off, clear the SACK scoreboard, reset 619 * the FACK estimate. 620 */ 621 KERNEL_LOCK(1, NULL); 622 tcp_free_sackholes(tp); 623 tp->snd_fack = tp->snd_una; 624 625 #ifdef TCP_DEBUG 626 #ifdef INET 627 if (tp->t_inpcb) 628 so = tp->t_inpcb->inp_socket; 629 #endif 630 #ifdef INET6 631 if (tp->t_in6pcb) 632 so = tp->t_in6pcb->in6p_socket; 633 #endif 634 635 ostate = tp->t_state; 636 #endif /* TCP_DEBUG */ 637 638 /* 639 * 2 MSL timeout in shutdown went off. If we're closed but 640 * still waiting for peer to close and connection has been idle 641 * too long, or if 2MSL time is up from TIME_WAIT, delete connection 642 * control block. Otherwise, check again in a bit. 643 */ 644 if (tp->t_state != TCPS_TIME_WAIT && 645 ((tp->t_maxidle == 0) || 646 ((tcp_now - tp->t_rcvtime) <= tp->t_maxidle))) 647 TCP_TIMER_ARM(tp, TCPT_2MSL, tp->t_keepintvl); 648 else 649 tp = tcp_close(tp); 650 651 #ifdef TCP_DEBUG 652 if (tp && so->so_options & SO_DEBUG) 653 tcp_trace(TA_USER, ostate, tp, NULL, 654 PRU_SLOWTIMO | (TCPT_2MSL << 8)); 655 #endif 656 mutex_exit(softnet_lock); 657 KERNEL_UNLOCK_ONE(NULL); 658 } 659
Indexes created Sun Sep 21 15:09:59 GMT 2025