tcp_timer.c revision 1.52
1 /* $NetBSD: tcp_timer.c,v 1.52 2001/09/10 20:36:43 thorpej 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 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 * 40 * Redistribution and use in source and binary forms, with or without 41 * modification, are permitted provided that the following conditions 42 * are met: 43 * 1. Redistributions of source code must retain the above copyright 44 * notice, this list of conditions and the following disclaimer. 45 * 2. Redistributions in binary form must reproduce the above copyright 46 * notice, this list of conditions and the following disclaimer in the 47 * documentation and/or other materials provided with the distribution. 48 * 3. All advertising materials mentioning features or use of this software 49 * must display the following acknowledgement: 50 * This product includes software developed by the NetBSD 51 * Foundation, Inc. and its contributors. 52 * 4. Neither the name of The NetBSD Foundation nor the names of its 53 * contributors may be used to endorse or promote products derived 54 * from this software without specific prior written permission. 55 * 56 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 57 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 58 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 59 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 60 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 61 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 62 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 63 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 64 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 65 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 66 * POSSIBILITY OF SUCH DAMAGE. 67 */ 68 69 /* 70 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 71 * The Regents of the University of California. All rights reserved. 72 * 73 * Redistribution and use in source and binary forms, with or without 74 * modification, are permitted provided that the following conditions 75 * are met: 76 * 1. Redistributions of source code must retain the above copyright 77 * notice, this list of conditions and the following disclaimer. 78 * 2. Redistributions in binary form must reproduce the above copyright 79 * notice, this list of conditions and the following disclaimer in the 80 * documentation and/or other materials provided with the distribution. 81 * 3. All advertising materials mentioning features or use of this software 82 * must display the following acknowledgement: 83 * This product includes software developed by the University of 84 * California, Berkeley and its contributors. 85 * 4. Neither the name of the University nor the names of its contributors 86 * may be used to endorse or promote products derived from this software 87 * without specific prior written permission. 88 * 89 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 90 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 91 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 92 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 93 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 94 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 95 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 96 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 97 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 98 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 99 * SUCH DAMAGE. 100 * 101 * @(#)tcp_timer.c 8.2 (Berkeley) 5/24/95 102 */ 103 104 #include "opt_inet.h" 105 #include "opt_tcp_debug.h" 106 107 #include <sys/param.h> 108 #include <sys/systm.h> 109 #include <sys/malloc.h> 110 #include <sys/mbuf.h> 111 #include <sys/socket.h> 112 #include <sys/socketvar.h> 113 #include <sys/protosw.h> 114 #include <sys/errno.h> 115 #include <sys/kernel.h> 116 117 #include <net/if.h> 118 #include <net/route.h> 119 120 #include <netinet/in.h> 121 #include <netinet/in_systm.h> 122 #include <netinet/ip.h> 123 #include <netinet/in_pcb.h> 124 #include <netinet/ip_var.h> 125 126 #ifdef INET6 127 #ifndef INET 128 #include <netinet/in.h> 129 #endif 130 #include <netinet/ip6.h> 131 #include <netinet6/in6_pcb.h> 132 #endif 133 134 #include <netinet/tcp.h> 135 #include <netinet/tcp_fsm.h> 136 #include <netinet/tcp_seq.h> 137 #include <netinet/tcp_timer.h> 138 #include <netinet/tcp_var.h> 139 #include <netinet/tcpip.h> 140 #ifdef TCP_DEBUG 141 #include <netinet/tcp_debug.h> 142 #endif 143 144 /* 145 * Various tunable timer parameters. These are initialized in tcp_init(), 146 * unless they are patched. 147 */ 148 int tcp_keepidle = 0; 149 int tcp_keepintvl = 0; 150 int tcp_keepcnt = 0; /* max idle probes */ 151 int tcp_maxpersistidle = 0; /* max idle time in persist */ 152 int tcp_maxidle; /* computed in tcp_slowtimo() */ 153 154 /* 155 * Time to delay the ACK. This is initialized in tcp_init(), unless 156 * its patched. 157 */ 158 int tcp_delack_ticks = 0; 159 160 void tcp_timer_rexmt(void *); 161 void tcp_timer_persist(void *); 162 void tcp_timer_keep(void *); 163 void tcp_timer_2msl(void *); 164 165 tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS] = { 166 tcp_timer_rexmt, 167 tcp_timer_persist, 168 tcp_timer_keep, 169 tcp_timer_2msl, 170 }; 171 172 /* 173 * Timer state initialization, called from tcp_init(). 174 */ 175 void 176 tcp_timer_init(void) 177 { 178 179 if (tcp_keepidle == 0) 180 tcp_keepidle = TCPTV_KEEP_IDLE; 181 182 if (tcp_keepintvl == 0) 183 tcp_keepintvl = TCPTV_KEEPINTVL; 184 185 if (tcp_keepcnt == 0) 186 tcp_keepcnt = TCPTV_KEEPCNT; 187 188 if (tcp_maxpersistidle == 0) 189 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 190 191 if (tcp_delack_ticks == 0) 192 tcp_delack_ticks = TCP_DELACK_TICKS; 193 } 194 195 /* 196 * Callout to process delayed ACKs for a TCPCB. 197 */ 198 void 199 tcp_delack(void *arg) 200 { 201 struct tcpcb *tp = arg; 202 int s; 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 s = splsoftnet(); 211 tp->t_flags |= TF_ACKNOW; 212 (void) tcp_output(tp); 213 splx(s); 214 } 215 216 /* 217 * Tcp protocol timeout routine called every 500 ms. 218 * Updates the timers in all active tcb's and 219 * causes finite state machine actions if timers expire. 220 */ 221 void 222 tcp_slowtimo() 223 { 224 struct inpcb *inp, *ninp; 225 struct tcpcb *tp; 226 #ifdef INET6 227 struct in6pcb *in6p, *nin6p; 228 #endif 229 int s; 230 long i; 231 static int syn_cache_last = 0; 232 int skip, mask; 233 234 skip = mask = 0; 235 236 s = splsoftnet(); 237 tcp_maxidle = tcp_keepcnt * tcp_keepintvl; 238 /* 239 * Search through tcb's and update active timers. 240 */ 241 mask |= 1; 242 inp = tcbtable.inpt_queue.cqh_first; 243 if (inp == (struct inpcb *)0) { /* XXX */ 244 skip |= 1; 245 goto dotcb6; 246 } 247 for (; inp != (struct inpcb *)&tcbtable.inpt_queue; inp = ninp) { 248 ninp = inp->inp_queue.cqe_next; 249 tp = intotcpcb(inp); 250 if (tp == 0 || tp->t_state == TCPS_LISTEN) 251 continue; 252 for (i = 0; i < TCPT_NTIMERS; i++) { 253 if (TCP_TIMER_ISEXPIRED(tp, i)) { 254 TCP_TIMER_DISARM(tp, i); 255 (*(tcp_timer_funcs[i]))(tp); 256 /* XXX NOT MP SAFE */ 257 if ((ninp == (void *)&tcbtable.inpt_queue && 258 tcbtable.inpt_queue.cqh_last != inp) || 259 ninp->inp_queue.cqe_prev != inp) 260 goto tpgone; 261 } 262 } 263 tpgone: 264 ; 265 } 266 dotcb6: 267 #ifdef INET6 268 mask |= 2; 269 in6p = tcb6.in6p_next; 270 if (in6p == (struct in6pcb *)0) { /* XXX */ 271 skip |= 2; 272 goto doiss; 273 } 274 for (; in6p != (struct in6pcb *)&tcb6; in6p = nin6p) { 275 nin6p = in6p->in6p_next; 276 tp = in6totcpcb(in6p); 277 if (tp == 0 || tp->t_state == TCPS_LISTEN) 278 continue; 279 for (i = 0; i < TCPT_NTIMERS; i++) { 280 if (TCP_TIMER_ISEXPIRED(tp, i)) { 281 TCP_TIMER_DISARM(tp, i); 282 (*(tcp_timer_funcs[i]))(tp); 283 /* XXX NOT MP SAFE */ 284 if ((nin6p == (void *)&tcb6 && 285 tcb6.in6p_prev != in6p) || 286 nin6p->in6p_prev != in6p) 287 goto tp6gone; 288 } 289 } 290 tp6gone: 291 ; 292 } 293 294 doiss: 295 #endif 296 if (mask == skip) 297 goto done; 298 tcp_iss_seq += TCP_ISSINCR; /* increment iss */ 299 tcp_now++; /* for timestamps */ 300 if (++syn_cache_last >= tcp_syn_cache_interval) { 301 syn_cache_timer(); 302 syn_cache_last = 0; 303 } 304 done: 305 splx(s); 306 } 307 308 /* 309 * Cancel all timers for TCP tp. 310 */ 311 void 312 tcp_canceltimers(tp) 313 struct tcpcb *tp; 314 { 315 int i; 316 317 for (i = 0; i < TCPT_NTIMERS; i++) 318 TCP_TIMER_DISARM(tp, i); 319 } 320 321 int tcp_backoff[TCP_MAXRXTSHIFT + 1] = 322 { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 }; 323 324 int tcp_totbackoff = 511; /* sum of tcp_backoff[] */ 325 326 /* 327 * TCP timer processing. 328 */ 329 330 void 331 tcp_timer_rexmt(void *arg) 332 { 333 struct tcpcb *tp = arg; 334 uint32_t rto; 335 int s; 336 #ifdef TCP_DEBUG 337 struct socket *so; 338 short ostate; 339 #endif 340 341 s = splsoftnet(); 342 343 #ifdef TCP_DEBUG 344 #ifdef INET 345 if (tp->t_inpcb) 346 so = tp->t_inpcb->inp_socket; 347 #endif 348 #ifdef INET6 349 if (tp->t_in6pcb) 350 so = tp->t_in6pcb->in6p_socket; 351 #endif 352 ostate = tp->t_state; 353 #endif /* TCP_DEBUG */ 354 355 /* 356 * Retransmission timer went off. Message has not 357 * been acked within retransmit interval. Back off 358 * to a longer retransmit interval and retransmit one segment. 359 */ 360 361 if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { 362 tp->t_rxtshift = TCP_MAXRXTSHIFT; 363 tcpstat.tcps_timeoutdrop++; 364 tp = tcp_drop(tp, tp->t_softerror ? 365 tp->t_softerror : ETIMEDOUT); 366 goto out; 367 } 368 tcpstat.tcps_rexmttimeo++; 369 rto = TCP_REXMTVAL(tp); 370 if (rto < tp->t_rttmin) 371 rto = tp->t_rttmin; 372 TCPT_RANGESET(tp->t_rxtcur, rto * tcp_backoff[tp->t_rxtshift], 373 tp->t_rttmin, TCPTV_REXMTMAX); 374 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 375 #if 0 376 /* 377 * If we are losing and we are trying path MTU discovery, 378 * try turning it off. This will avoid black holes in 379 * the network which suppress or fail to send "packet 380 * too big" ICMP messages. We should ideally do 381 * lots more sophisticated searching to find the right 382 * value here... 383 */ 384 if (ip_mtudisc && tp->t_rxtshift > TCP_MAXRXTSHIFT / 6) { 385 struct rtentry *rt = NULL; 386 387 #ifdef INET 388 if (tp->t_inpcb) 389 rt = in_pcbrtentry(tp->t_inpcb); 390 #endif 391 #ifdef INET6 392 if (tp->t_in6pcb) 393 rt = in6_pcbrtentry(tp->t_in6pcb); 394 #endif 395 396 /* XXX: Black hole recovery code goes here */ 397 } 398 #endif /* 0 */ 399 /* 400 * If losing, let the lower level know and try for 401 * a better route. Also, if we backed off this far, 402 * our srtt estimate is probably bogus. Clobber it 403 * so we'll take the next rtt measurement as our srtt; 404 * move the current srtt into rttvar to keep the current 405 * retransmit times until then. 406 */ 407 if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { 408 #ifdef INET 409 if (tp->t_inpcb) 410 in_losing(tp->t_inpcb); 411 #endif 412 #ifdef INET6 413 if (tp->t_in6pcb) 414 in6_losing(tp->t_in6pcb); 415 #endif 416 tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); 417 tp->t_srtt = 0; 418 } 419 tp->snd_nxt = tp->snd_una; 420 /* 421 * If timing a segment in this window, stop the timer. 422 */ 423 tp->t_rtttime = 0; 424 /* 425 * Remember if we are retransmitting a SYN, because if 426 * we do, set the initial congestion window must be set 427 * to 1 segment. 428 */ 429 if (tp->t_state == TCPS_SYN_SENT) 430 tp->t_flags |= TF_SYN_REXMT; 431 /* 432 * Close the congestion window down to one segment 433 * (we'll open it by one segment for each ack we get). 434 * Since we probably have a window's worth of unacked 435 * data accumulated, this "slow start" keeps us from 436 * dumping all that data as back-to-back packets (which 437 * might overwhelm an intermediate gateway). 438 * 439 * There are two phases to the opening: Initially we 440 * open by one mss on each ack. This makes the window 441 * size increase exponentially with time. If the 442 * window is larger than the path can handle, this 443 * exponential growth results in dropped packet(s) 444 * almost immediately. To get more time between 445 * drops but still "push" the network to take advantage 446 * of improving conditions, we switch from exponential 447 * to linear window opening at some threshhold size. 448 * For a threshhold, we use half the current window 449 * size, truncated to a multiple of the mss. 450 * 451 * (the minimum cwnd that will give us exponential 452 * growth is 2 mss. We don't allow the threshhold 453 * to go below this.) 454 */ 455 { 456 u_int win = min(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_segsz; 457 if (win < 2) 458 win = 2; 459 /* Loss Window MUST be one segment. */ 460 tp->snd_cwnd = tp->t_segsz; 461 tp->snd_ssthresh = win * tp->t_segsz; 462 tp->t_dupacks = 0; 463 } 464 (void) tcp_output(tp); 465 466 out: 467 #ifdef TCP_DEBUG 468 if (tp && so->so_options & SO_DEBUG) 469 tcp_trace(TA_USER, ostate, tp, NULL, 470 PRU_SLOWTIMO | (TCPT_REXMT << 8)); 471 #endif 472 splx(s); 473 } 474 475 void 476 tcp_timer_persist(void *arg) 477 { 478 struct tcpcb *tp = arg; 479 struct socket *so; 480 uint32_t rto; 481 int s; 482 #ifdef TCP_DEBUG 483 short ostate; 484 #endif 485 486 s = splsoftnet(); 487 488 #ifdef INET 489 if (tp->t_inpcb) 490 so = tp->t_inpcb->inp_socket; 491 #endif 492 #ifdef INET6 493 if (tp->t_in6pcb) 494 so = tp->t_in6pcb->in6p_socket; 495 #endif 496 497 #ifdef TCP_DEBUG 498 ostate = tp->t_state; 499 #endif 500 501 /* 502 * Persistance timer into zero window. 503 * Force a byte to be output, if possible. 504 */ 505 506 /* 507 * Hack: if the peer is dead/unreachable, we do not 508 * time out if the window is closed. After a full 509 * backoff, drop the connection if the idle time 510 * (no responses to probes) reaches the maximum 511 * backoff that we would use if retransmitting. 512 */ 513 rto = TCP_REXMTVAL(tp); 514 if (rto < tp->t_rttmin) 515 rto = tp->t_rttmin; 516 if (tp->t_rxtshift == TCP_MAXRXTSHIFT && 517 ((tcp_now - tp->t_rcvtime) >= tcp_maxpersistidle || 518 (tcp_now - tp->t_rcvtime) >= rto * tcp_totbackoff)) { 519 tcpstat.tcps_persistdrops++; 520 tp = tcp_drop(tp, ETIMEDOUT); 521 goto out; 522 } 523 tcpstat.tcps_persisttimeo++; 524 tcp_setpersist(tp); 525 tp->t_force = 1; 526 (void) tcp_output(tp); 527 tp->t_force = 0; 528 529 out: 530 #ifdef TCP_DEBUG 531 if (tp && so->so_options & SO_DEBUG) 532 tcp_trace(TA_USER, ostate, tp, NULL, 533 PRU_SLOWTIMO | (TCPT_PERSIST << 8)); 534 #endif 535 splx(s); 536 } 537 538 void 539 tcp_timer_keep(void *arg) 540 { 541 struct tcpcb *tp = arg; 542 struct socket *so; 543 int s; 544 #ifdef TCP_DEBUG 545 short ostate; 546 #endif 547 548 s = splsoftnet(); 549 550 #ifdef TCP_DEBUG 551 ostate = tp->t_state; 552 #endif /* TCP_DEBUG */ 553 554 /* 555 * Keep-alive timer went off; send something 556 * or drop connection if idle for too long. 557 */ 558 559 tcpstat.tcps_keeptimeo++; 560 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 561 goto dropit; 562 #ifdef INET 563 if (tp->t_inpcb) 564 so = tp->t_inpcb->inp_socket; 565 #endif 566 #ifdef INET6 567 if (tp->t_in6pcb) 568 so = tp->t_in6pcb->in6p_socket; 569 #endif 570 if (so->so_options & SO_KEEPALIVE && 571 tp->t_state <= TCPS_CLOSE_WAIT) { 572 if ((tcp_maxidle > 0) && 573 ((tcp_now - tp->t_rcvtime) >= 574 tcp_keepidle + tcp_maxidle)) 575 goto dropit; 576 /* 577 * Send a packet designed to force a response 578 * if the peer is up and reachable: 579 * either an ACK if the connection is still alive, 580 * or an RST if the peer has closed the connection 581 * due to timeout or reboot. 582 * Using sequence number tp->snd_una-1 583 * causes the transmitted zero-length segment 584 * to lie outside the receive window; 585 * by the protocol spec, this requires the 586 * correspondent TCP to respond. 587 */ 588 tcpstat.tcps_keepprobe++; 589 if (tcp_compat_42) { 590 /* 591 * The keepalive packet must have nonzero 592 * length to get a 4.2 host to respond. 593 */ 594 (void)tcp_respond(tp, tp->t_template, 595 (struct mbuf *)NULL, NULL, tp->rcv_nxt - 1, 596 tp->snd_una - 1, 0); 597 } else { 598 (void)tcp_respond(tp, tp->t_template, 599 (struct mbuf *)NULL, NULL, tp->rcv_nxt, 600 tp->snd_una - 1, 0); 601 } 602 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepintvl); 603 } else 604 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle); 605 606 #ifdef TCP_DEBUG 607 if (tp && so->so_options & SO_DEBUG) 608 tcp_trace(TA_USER, ostate, tp, NULL, 609 PRU_SLOWTIMO | (TCPT_KEEP << 8)); 610 #endif 611 splx(s); 612 return; 613 614 dropit: 615 tcpstat.tcps_keepdrops++; 616 (void) tcp_drop(tp, ETIMEDOUT); 617 splx(s); 618 } 619 620 void 621 tcp_timer_2msl(void *arg) 622 { 623 struct tcpcb *tp = arg; 624 struct socket *so; 625 int s; 626 #ifdef TCP_DEBUG 627 short ostate; 628 #endif 629 630 s = splsoftnet(); 631 632 #ifdef INET 633 if (tp->t_inpcb) 634 so = tp->t_inpcb->inp_socket; 635 #endif 636 #ifdef INET6 637 if (tp->t_in6pcb) 638 so = tp->t_in6pcb->in6p_socket; 639 #endif 640 641 #ifdef TCP_DEBUG 642 ostate = tp->t_state; 643 #endif 644 645 /* 646 * 2 MSL timeout in shutdown went off. If we're closed but 647 * still waiting for peer to close and connection has been idle 648 * too long, or if 2MSL time is up from TIME_WAIT, delete connection 649 * control block. Otherwise, check again in a bit. 650 */ 651 if (tp->t_state != TCPS_TIME_WAIT && 652 ((tcp_maxidle == 0) || ((tcp_now - tp->t_rcvtime) <= tcp_maxidle))) 653 TCP_TIMER_ARM(tp, TCPT_2MSL, tcp_keepintvl); 654 else 655 tp = tcp_close(tp); 656 657 #ifdef TCP_DEBUG 658 if (tp && so->so_options & SO_DEBUG) 659 tcp_trace(TA_USER, ostate, tp, NULL, 660 PRU_SLOWTIMO | (TCPT_2MSL << 8)); 661 #endif 662 splx(s); 663 } 664
Indexes created Tue Sep 23 02:09:52 GMT 2025