1 /* $NetBSD: tcp_timer.c,v 1.89 2015/08/24 22:21:26 pooka 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 1.89 2015/08/24 22:21:26 pooka 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 #include <net/route.h> 114 115 #include <netinet/in.h> 116 #include <netinet/in_systm.h> 117 #include <netinet/ip.h> 118 #include <netinet/in_pcb.h> 119 #include <netinet/ip_var.h> 120 #include <netinet/ip_icmp.h> 121 122 #ifdef INET6 123 #ifndef INET 124 #include <netinet/in.h> 125 #endif 126 #include <netinet/ip6.h> 127 #include <netinet6/in6_pcb.h> 128 #endif 129 130 #include <netinet/tcp.h> 131 #include <netinet/tcp_fsm.h> 132 #include <netinet/tcp_seq.h> 133 #include <netinet/tcp_timer.h> 134 #include <netinet/tcp_var.h> 135 #include <netinet/tcp_private.h> 136 #include <netinet/tcp_congctl.h> 137 #include <netinet/tcpip.h> 138 #ifdef TCP_DEBUG 139 #include <netinet/tcp_debug.h> 140 #endif 141 142 /* 143 * Various tunable timer parameters. These are initialized in tcp_init(), 144 * unless they are patched. 145 */ 146 u_int tcp_keepinit = 0; 147 u_int tcp_keepidle = 0; 148 u_int tcp_keepintvl = 0; 149 u_int tcp_keepcnt = 0; /* max idle probes */ 150 151 int tcp_maxpersistidle = 0; /* max idle time in persist */ 152 153 /* 154 * Time to delay the ACK. This is initialized in tcp_init(), unless 155 * its patched. 156 */ 157 int tcp_delack_ticks = 0; 158 159 void tcp_timer_rexmt(void *); 160 void tcp_timer_persist(void *); 161 void tcp_timer_keep(void *); 162 void tcp_timer_2msl(void *); 163 164 const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS] = { 165 tcp_timer_rexmt, 166 tcp_timer_persist, 167 tcp_timer_keep, 168 tcp_timer_2msl, 169 }; 170 171 /* 172 * Timer state initialization, called from tcp_init(). 173 */ 174 void 175 tcp_timer_init(void) 176 { 177 178 if (tcp_keepinit == 0) 179 tcp_keepinit = TCPTV_KEEP_INIT; 180 181 if (tcp_keepidle == 0) 182 tcp_keepidle = TCPTV_KEEP_IDLE; 183 184 if (tcp_keepintvl == 0) 185 tcp_keepintvl = TCPTV_KEEPINTVL; 186 187 if (tcp_keepcnt == 0) 188 tcp_keepcnt = TCPTV_KEEPCNT; 189 190 if (tcp_maxpersistidle == 0) 191 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 192 193 if (tcp_delack_ticks == 0) 194 tcp_delack_ticks = TCP_DELACK_TICKS; 195 } 196 197 /* 198 * Callout to process delayed ACKs for a TCPCB. 199 */ 200 void 201 tcp_delack(void *arg) 202 { 203 struct tcpcb *tp = arg; 204 205 /* 206 * If tcp_output() wasn't able to transmit the ACK 207 * for whatever reason, it will restart the delayed 208 * ACK callout. 209 */ 210 211 mutex_enter(softnet_lock); 212 if ((tp->t_flags & (TF_DEAD | TF_DELACK)) != TF_DELACK) { 213 mutex_exit(softnet_lock); 214 return; 215 } 216 if (!callout_expired(&tp->t_delack_ch)) { 217 mutex_exit(softnet_lock); 218 return; 219 } 220 221 tp->t_flags |= TF_ACKNOW; 222 KERNEL_LOCK(1, NULL); 223 (void) tcp_output(tp); 224 KERNEL_UNLOCK_ONE(NULL); 225 mutex_exit(softnet_lock); 226 } 227 228 /* 229 * Tcp protocol timeout routine called every 500 ms. 230 * Updates the timers in all active tcb's and 231 * causes finite state machine actions if timers expire. 232 */ 233 void 234 tcp_slowtimo(void *arg) 235 { 236 237 mutex_enter(softnet_lock); 238 tcp_iss_seq += TCP_ISSINCR; /* increment iss */ 239 tcp_now++; /* for timestamps */ 240 mutex_exit(softnet_lock); 241 242 callout_schedule(&tcp_slowtimo_ch, hz / PR_SLOWHZ); 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 if (!callout_expired(&tp->t_timer[TCPT_REXMT])) { 282 mutex_exit(softnet_lock); 283 return; 284 } 285 286 KERNEL_LOCK(1, NULL); 287 if ((tp->t_flags & TF_PMTUD_PEND) && tp->t_inpcb && 288 SEQ_GEQ(tp->t_pmtud_th_seq, tp->snd_una) && 289 SEQ_LT(tp->t_pmtud_th_seq, (int)(tp->snd_una + tp->t_ourmss))) { 290 extern struct sockaddr_in icmpsrc; 291 struct icmp icmp; 292 293 tp->t_flags &= ~TF_PMTUD_PEND; 294 295 /* XXX create fake icmp message with relevant entries */ 296 icmp.icmp_nextmtu = tp->t_pmtud_nextmtu; 297 icmp.icmp_ip.ip_len = tp->t_pmtud_ip_len; 298 icmp.icmp_ip.ip_hl = tp->t_pmtud_ip_hl; 299 icmpsrc.sin_addr = tp->t_inpcb->inp_faddr; 300 icmp_mtudisc(&icmp, icmpsrc.sin_addr); 301 302 /* 303 * Notify all connections to the same peer about 304 * new mss and trigger retransmit. 305 */ 306 in_pcbnotifyall(&tcbtable, icmpsrc.sin_addr, EMSGSIZE, 307 tcp_mtudisc); 308 KERNEL_UNLOCK_ONE(NULL); 309 mutex_exit(softnet_lock); 310 return; 311 } 312 #ifdef TCP_DEBUG 313 #ifdef INET 314 if (tp->t_inpcb) 315 so = tp->t_inpcb->inp_socket; 316 #endif 317 #ifdef INET6 318 if (tp->t_in6pcb) 319 so = tp->t_in6pcb->in6p_socket; 320 #endif 321 ostate = tp->t_state; 322 #endif /* TCP_DEBUG */ 323 324 /* 325 * Clear the SACK scoreboard, reset FACK estimate. 326 */ 327 tcp_free_sackholes(tp); 328 tp->snd_fack = tp->snd_una; 329 330 /* 331 * Retransmission timer went off. Message has not 332 * been acked within retransmit interval. Back off 333 * to a longer retransmit interval and retransmit one segment. 334 */ 335 336 if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { 337 tp->t_rxtshift = TCP_MAXRXTSHIFT; 338 TCP_STATINC(TCP_STAT_TIMEOUTDROP); 339 tp = tcp_drop(tp, tp->t_softerror ? 340 tp->t_softerror : ETIMEDOUT); 341 goto out; 342 } 343 TCP_STATINC(TCP_STAT_REXMTTIMEO); 344 rto = TCP_REXMTVAL(tp); 345 if (rto < tp->t_rttmin) 346 rto = tp->t_rttmin; 347 TCPT_RANGESET(tp->t_rxtcur, rto * tcp_backoff[tp->t_rxtshift], 348 tp->t_rttmin, TCPTV_REXMTMAX); 349 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 350 351 /* 352 * If we are losing and we are trying path MTU discovery, 353 * try turning it off. This will avoid black holes in 354 * the network which suppress or fail to send "packet 355 * too big" ICMP messages. We should ideally do 356 * lots more sophisticated searching to find the right 357 * value here... 358 */ 359 if (tp->t_mtudisc && tp->t_rxtshift > TCP_MAXRXTSHIFT / 6) { 360 TCP_STATINC(TCP_STAT_PMTUBLACKHOLE); 361 362 #ifdef INET 363 /* try turning PMTUD off */ 364 if (tp->t_inpcb) 365 tp->t_mtudisc = 0; 366 #endif 367 #ifdef INET6 368 /* try using IPv6 minimum MTU */ 369 if (tp->t_in6pcb) 370 tp->t_mtudisc = 0; 371 #endif 372 373 /* XXX: more sophisticated Black hole recovery code? */ 374 } 375 376 /* 377 * If losing, let the lower level know and try for 378 * a better route. Also, if we backed off this far, 379 * our srtt estimate is probably bogus. Clobber it 380 * so we'll take the next rtt measurement as our srtt; 381 * move the current srtt into rttvar to keep the current 382 * retransmit times until then. 383 */ 384 if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { 385 #ifdef INET 386 if (tp->t_inpcb) 387 in_losing(tp->t_inpcb); 388 #endif 389 #ifdef INET6 390 if (tp->t_in6pcb) 391 in6_losing(tp->t_in6pcb); 392 #endif 393 /* 394 * This operation is not described in RFC2988. The 395 * point is to keep srtt+4*rttvar constant, so we 396 * should shift right 2 bits to divide by 4, and then 397 * shift right one bit because the storage 398 * representation of rttvar is 1/16s vs 1/32s for 399 * srtt. 400 */ 401 tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); 402 tp->t_srtt = 0; 403 } 404 tp->snd_nxt = tp->snd_una; 405 tp->snd_high = tp->snd_max; 406 /* 407 * If timing a segment in this window, stop the timer. 408 */ 409 tp->t_rtttime = 0; 410 /* 411 * Remember if we are retransmitting a SYN, because if 412 * we do, set the initial congestion window must be set 413 * to 1 segment. 414 */ 415 if (tp->t_state == TCPS_SYN_SENT) 416 tp->t_flags |= TF_SYN_REXMT; 417 418 /* 419 * Adjust congestion control parameters. 420 */ 421 tp->t_congctl->slow_retransmit(tp); 422 423 (void) tcp_output(tp); 424 425 out: 426 #ifdef TCP_DEBUG 427 if (tp && so->so_options & SO_DEBUG) 428 tcp_trace(TA_USER, ostate, tp, NULL, 429 PRU_SLOWTIMO | (TCPT_REXMT << 8)); 430 #endif 431 KERNEL_UNLOCK_ONE(NULL); 432 mutex_exit(softnet_lock); 433 } 434 435 void 436 tcp_timer_persist(void *arg) 437 { 438 struct tcpcb *tp = arg; 439 uint32_t rto; 440 #ifdef TCP_DEBUG 441 struct socket *so = NULL; 442 short ostate; 443 #endif 444 445 mutex_enter(softnet_lock); 446 if ((tp->t_flags & TF_DEAD) != 0) { 447 mutex_exit(softnet_lock); 448 return; 449 } 450 if (!callout_expired(&tp->t_timer[TCPT_PERSIST])) { 451 mutex_exit(softnet_lock); 452 return; 453 } 454 455 KERNEL_LOCK(1, NULL); 456 #ifdef TCP_DEBUG 457 #ifdef INET 458 if (tp->t_inpcb) 459 so = tp->t_inpcb->inp_socket; 460 #endif 461 #ifdef INET6 462 if (tp->t_in6pcb) 463 so = tp->t_in6pcb->in6p_socket; 464 #endif 465 466 ostate = tp->t_state; 467 #endif /* TCP_DEBUG */ 468 469 /* 470 * Persistance timer into zero window. 471 * Force a byte to be output, if possible. 472 */ 473 474 /* 475 * Hack: if the peer is dead/unreachable, we do not 476 * time out if the window is closed. After a full 477 * backoff, drop the connection if the idle time 478 * (no responses to probes) reaches the maximum 479 * backoff that we would use if retransmitting. 480 */ 481 rto = TCP_REXMTVAL(tp); 482 if (rto < tp->t_rttmin) 483 rto = tp->t_rttmin; 484 if (tp->t_rxtshift == TCP_MAXRXTSHIFT && 485 ((tcp_now - tp->t_rcvtime) >= tcp_maxpersistidle || 486 (tcp_now - tp->t_rcvtime) >= rto * tcp_totbackoff)) { 487 TCP_STATINC(TCP_STAT_PERSISTDROPS); 488 tp = tcp_drop(tp, ETIMEDOUT); 489 goto out; 490 } 491 TCP_STATINC(TCP_STAT_PERSISTTIMEO); 492 tcp_setpersist(tp); 493 tp->t_force = 1; 494 (void) tcp_output(tp); 495 tp->t_force = 0; 496 497 out: 498 #ifdef TCP_DEBUG 499 if (tp && so->so_options & SO_DEBUG) 500 tcp_trace(TA_USER, ostate, tp, NULL, 501 PRU_SLOWTIMO | (TCPT_PERSIST << 8)); 502 #endif 503 KERNEL_UNLOCK_ONE(NULL); 504 mutex_exit(softnet_lock); 505 } 506 507 void 508 tcp_timer_keep(void *arg) 509 { 510 struct tcpcb *tp = arg; 511 struct socket *so = NULL; /* Quell compiler warning */ 512 #ifdef TCP_DEBUG 513 short ostate; 514 #endif 515 516 mutex_enter(softnet_lock); 517 if ((tp->t_flags & TF_DEAD) != 0) { 518 mutex_exit(softnet_lock); 519 return; 520 } 521 if (!callout_expired(&tp->t_timer[TCPT_KEEP])) { 522 mutex_exit(softnet_lock); 523 return; 524 } 525 526 KERNEL_LOCK(1, NULL); 527 528 #ifdef TCP_DEBUG 529 ostate = tp->t_state; 530 #endif /* TCP_DEBUG */ 531 532 /* 533 * Keep-alive timer went off; send something 534 * or drop connection if idle for too long. 535 */ 536 537 TCP_STATINC(TCP_STAT_KEEPTIMEO); 538 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 539 goto dropit; 540 #ifdef INET 541 if (tp->t_inpcb) 542 so = tp->t_inpcb->inp_socket; 543 #endif 544 #ifdef INET6 545 if (tp->t_in6pcb) 546 so = tp->t_in6pcb->in6p_socket; 547 #endif 548 KASSERT(so != NULL); 549 if (so->so_options & SO_KEEPALIVE && 550 tp->t_state <= TCPS_CLOSE_WAIT) { 551 if ((tp->t_maxidle > 0) && 552 ((tcp_now - tp->t_rcvtime) >= 553 tp->t_keepidle + tp->t_maxidle)) 554 goto dropit; 555 /* 556 * Send a packet designed to force a response 557 * if the peer is up and reachable: 558 * either an ACK if the connection is still alive, 559 * or an RST if the peer has closed the connection 560 * due to timeout or reboot. 561 * Using sequence number tp->snd_una-1 562 * causes the transmitted zero-length segment 563 * to lie outside the receive window; 564 * by the protocol spec, this requires the 565 * correspondent TCP to respond. 566 */ 567 TCP_STATINC(TCP_STAT_KEEPPROBE); 568 if (tcp_compat_42) { 569 /* 570 * The keepalive packet must have nonzero 571 * length to get a 4.2 host to respond. 572 */ 573 (void)tcp_respond(tp, tp->t_template, 574 NULL, NULL, tp->rcv_nxt - 1, 575 tp->snd_una - 1, 0); 576 } else { 577 (void)tcp_respond(tp, tp->t_template, 578 NULL, NULL, tp->rcv_nxt, 579 tp->snd_una - 1, 0); 580 } 581 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepintvl); 582 } else 583 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepidle); 584 585 #ifdef TCP_DEBUG 586 if (tp && so->so_options & SO_DEBUG) 587 tcp_trace(TA_USER, ostate, tp, NULL, 588 PRU_SLOWTIMO | (TCPT_KEEP << 8)); 589 #endif 590 KERNEL_UNLOCK_ONE(NULL); 591 mutex_exit(softnet_lock); 592 return; 593 594 dropit: 595 TCP_STATINC(TCP_STAT_KEEPDROPS); 596 (void) tcp_drop(tp, ETIMEDOUT); 597 KERNEL_UNLOCK_ONE(NULL); 598 mutex_exit(softnet_lock); 599 } 600 601 void 602 tcp_timer_2msl(void *arg) 603 { 604 struct tcpcb *tp = arg; 605 #ifdef TCP_DEBUG 606 struct socket *so = NULL; 607 short ostate; 608 #endif 609 610 mutex_enter(softnet_lock); 611 if ((tp->t_flags & TF_DEAD) != 0) { 612 mutex_exit(softnet_lock); 613 return; 614 } 615 if (!callout_expired(&tp->t_timer[TCPT_2MSL])) { 616 mutex_exit(softnet_lock); 617 return; 618 } 619 620 /* 621 * 2 MSL timeout went off, clear the SACK scoreboard, reset 622 * the FACK estimate. 623 */ 624 KERNEL_LOCK(1, NULL); 625 tcp_free_sackholes(tp); 626 tp->snd_fack = tp->snd_una; 627 628 #ifdef TCP_DEBUG 629 #ifdef INET 630 if (tp->t_inpcb) 631 so = tp->t_inpcb->inp_socket; 632 #endif 633 #ifdef INET6 634 if (tp->t_in6pcb) 635 so = tp->t_in6pcb->in6p_socket; 636 #endif 637 638 ostate = tp->t_state; 639 #endif /* TCP_DEBUG */ 640 641 /* 642 * 2 MSL timeout in shutdown went off. If we're closed but 643 * still waiting for peer to close and connection has been idle 644 * too long, or if 2MSL time is up from TIME_WAIT, delete connection 645 * control block. Otherwise, check again in a bit. 646 */ 647 if (tp->t_state != TCPS_TIME_WAIT && 648 ((tp->t_maxidle == 0) || 649 ((tcp_now - tp->t_rcvtime) <= tp->t_maxidle))) 650 TCP_TIMER_ARM(tp, TCPT_2MSL, tp->t_keepintvl); 651 else 652 tp = tcp_close(tp); 653 654 #ifdef TCP_DEBUG 655 if (tp && so->so_options & SO_DEBUG) 656 tcp_trace(TA_USER, ostate, tp, NULL, 657 PRU_SLOWTIMO | (TCPT_2MSL << 8)); 658 #endif 659 mutex_exit(softnet_lock); 660 KERNEL_UNLOCK_ONE(NULL); 661 } 662