tcp_timer.c revision 1.77
1 /* $NetBSD: tcp_timer.c,v 1.77 2007/06/20 15:29:18 christos 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 1.77 2007/06/20 15:29:18 christos 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_congctl.h> 142 #include <netinet/tcpip.h> 143 #ifdef TCP_DEBUG 144 #include <netinet/tcp_debug.h> 145 #endif 146 147 /* 148 * Various tunable timer parameters. These are initialized in tcp_init(), 149 * unless they are patched. 150 */ 151 u_int tcp_keepinit = 0; 152 u_int tcp_keepidle = 0; 153 u_int tcp_keepintvl = 0; 154 u_int tcp_keepcnt = 0; /* max idle probes */ 155 156 int tcp_maxpersistidle = 0; /* max idle time in persist */ 157 158 /* 159 * Time to delay the ACK. This is initialized in tcp_init(), unless 160 * its patched. 161 */ 162 int tcp_delack_ticks = 0; 163 164 void tcp_timer_rexmt(void *); 165 void tcp_timer_persist(void *); 166 void tcp_timer_keep(void *); 167 void tcp_timer_2msl(void *); 168 169 const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS] = { 170 tcp_timer_rexmt, 171 tcp_timer_persist, 172 tcp_timer_keep, 173 tcp_timer_2msl, 174 }; 175 176 /* 177 * Timer state initialization, called from tcp_init(). 178 */ 179 void 180 tcp_timer_init(void) 181 { 182 183 if (tcp_keepinit == 0) 184 tcp_keepinit = TCPTV_KEEP_INIT; 185 186 if (tcp_keepidle == 0) 187 tcp_keepidle = TCPTV_KEEP_IDLE; 188 189 if (tcp_keepintvl == 0) 190 tcp_keepintvl = TCPTV_KEEPINTVL; 191 192 if (tcp_keepcnt == 0) 193 tcp_keepcnt = TCPTV_KEEPCNT; 194 195 if (tcp_maxpersistidle == 0) 196 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 197 198 if (tcp_delack_ticks == 0) 199 tcp_delack_ticks = TCP_DELACK_TICKS; 200 } 201 202 /* 203 * Return how many timers are currently being invoked. 204 */ 205 int 206 tcp_timers_invoking(struct tcpcb *tp) 207 { 208 int i; 209 int count = 0; 210 211 for (i = 0; i < TCPT_NTIMERS; i++) 212 if (callout_invoking(&tp->t_timer[i])) 213 count++; 214 if (callout_invoking(&tp->t_delack_ch)) 215 count++; 216 217 return count; 218 } 219 220 /* 221 * Callout to process delayed ACKs for a TCPCB. 222 */ 223 void 224 tcp_delack(void *arg) 225 { 226 struct tcpcb *tp = arg; 227 int s; 228 229 /* 230 * If tcp_output() wasn't able to transmit the ACK 231 * for whatever reason, it will restart the delayed 232 * ACK callout. 233 */ 234 235 s = splsoftnet(); 236 callout_ack(&tp->t_delack_ch); 237 if (tcp_isdead(tp)) { 238 splx(s); 239 return; 240 } 241 242 tp->t_flags |= TF_ACKNOW; 243 (void) tcp_output(tp); 244 splx(s); 245 } 246 247 /* 248 * Tcp protocol timeout routine called every 500 ms. 249 * Updates the timers in all active tcb's and 250 * causes finite state machine actions if timers expire. 251 */ 252 void 253 tcp_slowtimo(void) 254 { 255 int s; 256 257 s = splsoftnet(); 258 tcp_iss_seq += TCP_ISSINCR; /* increment iss */ 259 tcp_now++; /* for timestamps */ 260 splx(s); 261 } 262 263 /* 264 * Cancel all timers for TCP tp. 265 */ 266 void 267 tcp_canceltimers(struct tcpcb *tp) 268 { 269 int i; 270 271 for (i = 0; i < TCPT_NTIMERS; i++) 272 TCP_TIMER_DISARM(tp, i); 273 } 274 275 const int tcp_backoff[TCP_MAXRXTSHIFT + 1] = 276 { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 }; 277 278 const int tcp_totbackoff = 511; /* sum of tcp_backoff[] */ 279 280 /* 281 * TCP timer processing. 282 */ 283 284 void 285 tcp_timer_rexmt(void *arg) 286 { 287 struct tcpcb *tp = arg; 288 uint32_t rto; 289 int s; 290 #ifdef TCP_DEBUG 291 struct socket *so = NULL; 292 short ostate; 293 #endif 294 295 s = splsoftnet(); 296 callout_ack(&tp->t_timer[TCPT_REXMT]); 297 if (tcp_isdead(tp)) { 298 splx(s); 299 return; 300 } 301 302 if ((tp->t_flags & TF_PMTUD_PEND) && tp->t_inpcb && 303 SEQ_GEQ(tp->t_pmtud_th_seq, tp->snd_una) && 304 SEQ_LT(tp->t_pmtud_th_seq, (int)(tp->snd_una + tp->t_ourmss))) { 305 extern struct sockaddr_in icmpsrc; 306 struct icmp icmp; 307 308 tp->t_flags &= ~TF_PMTUD_PEND; 309 310 /* XXX create fake icmp message with relevant entries */ 311 icmp.icmp_nextmtu = tp->t_pmtud_nextmtu; 312 icmp.icmp_ip.ip_len = tp->t_pmtud_ip_len; 313 icmp.icmp_ip.ip_hl = tp->t_pmtud_ip_hl; 314 icmpsrc.sin_addr = tp->t_inpcb->inp_faddr; 315 icmp_mtudisc(&icmp, icmpsrc.sin_addr); 316 317 /* 318 * Notify all connections to the same peer about 319 * new mss and trigger retransmit. 320 */ 321 in_pcbnotifyall(&tcbtable, icmpsrc.sin_addr, EMSGSIZE, 322 tcp_mtudisc); 323 splx(s); 324 return; 325 } 326 #ifdef TCP_DEBUG 327 #ifdef INET 328 if (tp->t_inpcb) 329 so = tp->t_inpcb->inp_socket; 330 #endif 331 #ifdef INET6 332 if (tp->t_in6pcb) 333 so = tp->t_in6pcb->in6p_socket; 334 #endif 335 ostate = tp->t_state; 336 #endif /* TCP_DEBUG */ 337 338 /* 339 * Clear the SACK scoreboard, reset FACK estimate. 340 */ 341 tcp_free_sackholes(tp); 342 tp->snd_fack = tp->snd_una; 343 344 /* 345 * Retransmission timer went off. Message has not 346 * been acked within retransmit interval. Back off 347 * to a longer retransmit interval and retransmit one segment. 348 */ 349 350 if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { 351 tp->t_rxtshift = TCP_MAXRXTSHIFT; 352 tcpstat.tcps_timeoutdrop++; 353 tp = tcp_drop(tp, tp->t_softerror ? 354 tp->t_softerror : ETIMEDOUT); 355 goto out; 356 } 357 tcpstat.tcps_rexmttimeo++; 358 rto = TCP_REXMTVAL(tp); 359 if (rto < tp->t_rttmin) 360 rto = tp->t_rttmin; 361 TCPT_RANGESET(tp->t_rxtcur, rto * tcp_backoff[tp->t_rxtshift], 362 tp->t_rttmin, TCPTV_REXMTMAX); 363 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 364 365 /* 366 * If we are losing and we are trying path MTU discovery, 367 * try turning it off. This will avoid black holes in 368 * the network which suppress or fail to send "packet 369 * too big" ICMP messages. We should ideally do 370 * lots more sophisticated searching to find the right 371 * value here... 372 */ 373 if (tp->t_mtudisc && tp->t_rxtshift > TCP_MAXRXTSHIFT / 6) { 374 tcpstat.tcps_pmtublackhole++; 375 376 #ifdef INET 377 /* try turning PMTUD off */ 378 if (tp->t_inpcb) 379 tp->t_mtudisc = 0; 380 #endif 381 #ifdef INET6 382 /* try using IPv6 minimum MTU */ 383 if (tp->t_in6pcb) 384 tp->t_mtudisc = 0; 385 #endif 386 387 /* XXX: more sophisticated Black hole recovery code? */ 388 } 389 390 /* 391 * If losing, let the lower level know and try for 392 * a better route. Also, if we backed off this far, 393 * our srtt estimate is probably bogus. Clobber it 394 * so we'll take the next rtt measurement as our srtt; 395 * move the current srtt into rttvar to keep the current 396 * retransmit times until then. 397 */ 398 if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { 399 #ifdef INET 400 if (tp->t_inpcb) 401 in_losing(tp->t_inpcb); 402 #endif 403 #ifdef INET6 404 if (tp->t_in6pcb) 405 in6_losing(tp->t_in6pcb); 406 #endif 407 tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); 408 tp->t_srtt = 0; 409 } 410 tp->snd_nxt = tp->snd_una; 411 tp->snd_high = tp->snd_max; 412 /* 413 * If timing a segment in this window, stop the timer. 414 */ 415 tp->t_rtttime = 0; 416 /* 417 * Remember if we are retransmitting a SYN, because if 418 * we do, set the initial congestion window must be set 419 * to 1 segment. 420 */ 421 if (tp->t_state == TCPS_SYN_SENT) 422 tp->t_flags |= TF_SYN_REXMT; 423 424 /* 425 * Adjust congestion control parameters. 426 */ 427 tp->t_congctl->slow_retransmit(tp); 428 429 (void) tcp_output(tp); 430 431 out: 432 #ifdef TCP_DEBUG 433 if (tp && so->so_options & SO_DEBUG) 434 tcp_trace(TA_USER, ostate, tp, NULL, 435 PRU_SLOWTIMO | (TCPT_REXMT << 8)); 436 #endif 437 splx(s); 438 } 439 440 void 441 tcp_timer_persist(void *arg) 442 { 443 struct tcpcb *tp = arg; 444 uint32_t rto; 445 int s; 446 #ifdef TCP_DEBUG 447 struct socket *so = NULL; 448 short ostate; 449 #endif 450 451 s = splsoftnet(); 452 callout_ack(&tp->t_timer[TCPT_PERSIST]); 453 if (tcp_isdead(tp)) { 454 splx(s); 455 return; 456 } 457 458 #ifdef TCP_DEBUG 459 #ifdef INET 460 if (tp->t_inpcb) 461 so = tp->t_inpcb->inp_socket; 462 #endif 463 #ifdef INET6 464 if (tp->t_in6pcb) 465 so = tp->t_in6pcb->in6p_socket; 466 #endif 467 468 ostate = tp->t_state; 469 #endif /* TCP_DEBUG */ 470 471 /* 472 * Persistance timer into zero window. 473 * Force a byte to be output, if possible. 474 */ 475 476 /* 477 * Hack: if the peer is dead/unreachable, we do not 478 * time out if the window is closed. After a full 479 * backoff, drop the connection if the idle time 480 * (no responses to probes) reaches the maximum 481 * backoff that we would use if retransmitting. 482 */ 483 rto = TCP_REXMTVAL(tp); 484 if (rto < tp->t_rttmin) 485 rto = tp->t_rttmin; 486 if (tp->t_rxtshift == TCP_MAXRXTSHIFT && 487 ((tcp_now - tp->t_rcvtime) >= tcp_maxpersistidle || 488 (tcp_now - tp->t_rcvtime) >= rto * tcp_totbackoff)) { 489 tcpstat.tcps_persistdrops++; 490 tp = tcp_drop(tp, ETIMEDOUT); 491 goto out; 492 } 493 tcpstat.tcps_persisttimeo++; 494 tcp_setpersist(tp); 495 tp->t_force = 1; 496 (void) tcp_output(tp); 497 tp->t_force = 0; 498 499 out: 500 #ifdef TCP_DEBUG 501 if (tp && so->so_options & SO_DEBUG) 502 tcp_trace(TA_USER, ostate, tp, NULL, 503 PRU_SLOWTIMO | (TCPT_PERSIST << 8)); 504 #endif 505 splx(s); 506 } 507 508 void 509 tcp_timer_keep(void *arg) 510 { 511 struct tcpcb *tp = arg; 512 struct socket *so = NULL; /* Quell compiler warning */ 513 int s; 514 #ifdef TCP_DEBUG 515 short ostate; 516 #endif 517 518 s = splsoftnet(); 519 callout_ack(&tp->t_timer[TCPT_KEEP]); 520 if (tcp_isdead(tp)) { 521 splx(s); 522 return; 523 } 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 tcpstat.tcps_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 tcpstat.tcps_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 splx(s); 588 return; 589 590 dropit: 591 tcpstat.tcps_keepdrops++; 592 (void) tcp_drop(tp, ETIMEDOUT); 593 splx(s); 594 } 595 596 void 597 tcp_timer_2msl(void *arg) 598 { 599 struct tcpcb *tp = arg; 600 int s; 601 #ifdef TCP_DEBUG 602 struct socket *so = NULL; 603 short ostate; 604 #endif 605 606 s = splsoftnet(); 607 callout_ack(&tp->t_timer[TCPT_2MSL]); 608 if (tcp_isdead(tp)) { 609 splx(s); 610 return; 611 } 612 613 /* 614 * 2 MSL timeout went off, clear the SACK scoreboard, reset 615 * the FACK estimate. 616 */ 617 tcp_free_sackholes(tp); 618 tp->snd_fack = tp->snd_una; 619 620 #ifdef TCP_DEBUG 621 #ifdef INET 622 if (tp->t_inpcb) 623 so = tp->t_inpcb->inp_socket; 624 #endif 625 #ifdef INET6 626 if (tp->t_in6pcb) 627 so = tp->t_in6pcb->in6p_socket; 628 #endif 629 630 ostate = tp->t_state; 631 #endif /* TCP_DEBUG */ 632 633 /* 634 * 2 MSL timeout in shutdown went off. If we're closed but 635 * still waiting for peer to close and connection has been idle 636 * too long, or if 2MSL time is up from TIME_WAIT, delete connection 637 * control block. Otherwise, check again in a bit. 638 */ 639 if (tp->t_state != TCPS_TIME_WAIT && 640 ((tp->t_maxidle == 0) || 641 ((tcp_now - tp->t_rcvtime) <= tp->t_maxidle))) 642 TCP_TIMER_ARM(tp, TCPT_2MSL, tp->t_keepintvl); 643 else 644 tp = tcp_close(tp); 645 646 #ifdef TCP_DEBUG 647 if (tp && so->so_options & SO_DEBUG) 648 tcp_trace(TA_USER, ostate, tp, NULL, 649 PRU_SLOWTIMO | (TCPT_2MSL << 8)); 650 #endif 651 splx(s); 652 } 653
Indexes created Sun Sep 21 20:09:37 GMT 2025