tcp_timer.c revision 1.71
1 /* $NetBSD: tcp_timer.c,v 1.71 2005/03/02 10:20:18 mycroft 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 1.71 2005/03/02 10:20:18 mycroft 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> 126 127 #ifdef INET6 128 #ifndef INET 129 #include <netinet/in.h> 130 #endif 131 #include <netinet/ip6.h> 132 #include <netinet6/in6_pcb.h> 133 #endif 134 135 #include <netinet/tcp.h> 136 #include <netinet/tcp_fsm.h> 137 #include <netinet/tcp_seq.h> 138 #include <netinet/tcp_timer.h> 139 #include <netinet/tcp_var.h> 140 #include <netinet/tcpip.h> 141 #ifdef TCP_DEBUG 142 #include <netinet/tcp_debug.h> 143 #endif 144 145 /* 146 * Various tunable timer parameters. These are initialized in tcp_init(), 147 * unless they are patched. 148 */ 149 int tcp_keepidle = 0; 150 int tcp_keepintvl = 0; 151 int tcp_keepcnt = 0; /* max idle probes */ 152 int tcp_maxpersistidle = 0; /* max idle time in persist */ 153 int tcp_maxidle; /* computed in tcp_slowtimo() */ 154 155 /* 156 * Time to delay the ACK. This is initialized in tcp_init(), unless 157 * its patched. 158 */ 159 int tcp_delack_ticks = 0; 160 161 void tcp_timer_rexmt(void *); 162 void tcp_timer_persist(void *); 163 void tcp_timer_keep(void *); 164 void tcp_timer_2msl(void *); 165 166 const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS] = { 167 tcp_timer_rexmt, 168 tcp_timer_persist, 169 tcp_timer_keep, 170 tcp_timer_2msl, 171 }; 172 173 /* 174 * Timer state initialization, called from tcp_init(). 175 */ 176 void 177 tcp_timer_init(void) 178 { 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 * Return how many timers are currently being invoked. 198 */ 199 int 200 tcp_timers_invoking(struct tcpcb *tp) 201 { 202 int i; 203 int count = 0; 204 205 for (i = 0; i < TCPT_NTIMERS; i++) 206 if (callout_invoking(&tp->t_timer[i])) 207 count++; 208 if (callout_invoking(&tp->t_delack_ch)) 209 count++; 210 211 return count; 212 } 213 214 /* 215 * Callout to process delayed ACKs for a TCPCB. 216 */ 217 void 218 tcp_delack(void *arg) 219 { 220 struct tcpcb *tp = arg; 221 int s; 222 223 /* 224 * If tcp_output() wasn't able to transmit the ACK 225 * for whatever reason, it will restart the delayed 226 * ACK callout. 227 */ 228 229 s = splsoftnet(); 230 callout_ack(&tp->t_delack_ch); 231 if (tcp_isdead(tp)) { 232 splx(s); 233 return; 234 } 235 236 tp->t_flags |= TF_ACKNOW; 237 (void) tcp_output(tp); 238 splx(s); 239 } 240 241 /* 242 * Tcp protocol timeout routine called every 500 ms. 243 * Updates the timers in all active tcb's and 244 * causes finite state machine actions if timers expire. 245 */ 246 void 247 tcp_slowtimo(void) 248 { 249 int s; 250 251 s = splsoftnet(); 252 tcp_maxidle = tcp_keepcnt * tcp_keepintvl; 253 tcp_iss_seq += TCP_ISSINCR; /* increment iss */ 254 tcp_now++; /* for timestamps */ 255 splx(s); 256 } 257 258 /* 259 * Cancel all timers for TCP tp. 260 */ 261 void 262 tcp_canceltimers(struct tcpcb *tp) 263 { 264 int i; 265 266 for (i = 0; i < TCPT_NTIMERS; i++) 267 TCP_TIMER_DISARM(tp, i); 268 } 269 270 const int tcp_backoff[TCP_MAXRXTSHIFT + 1] = 271 { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 }; 272 273 const int tcp_totbackoff = 511; /* sum of tcp_backoff[] */ 274 275 /* 276 * TCP timer processing. 277 */ 278 279 void 280 tcp_timer_rexmt(void *arg) 281 { 282 struct tcpcb *tp = arg; 283 uint32_t rto; 284 int s; 285 #ifdef TCP_DEBUG 286 struct socket *so = NULL; 287 short ostate; 288 #endif 289 290 s = splsoftnet(); 291 callout_ack(&tp->t_timer[TCPT_REXMT]); 292 if (tcp_isdead(tp)) { 293 splx(s); 294 return; 295 } 296 297 #ifdef TCP_DEBUG 298 #ifdef INET 299 if (tp->t_inpcb) 300 so = tp->t_inpcb->inp_socket; 301 #endif 302 #ifdef INET6 303 if (tp->t_in6pcb) 304 so = tp->t_in6pcb->in6p_socket; 305 #endif 306 ostate = tp->t_state; 307 #endif /* TCP_DEBUG */ 308 309 /* 310 * Clear the SACK scoreboard, reset FACK estimate. 311 */ 312 tcp_free_sackholes(tp); 313 tp->snd_fack = tp->snd_una; 314 315 /* 316 * Retransmission timer went off. Message has not 317 * been acked within retransmit interval. Back off 318 * to a longer retransmit interval and retransmit one segment. 319 */ 320 321 if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { 322 tp->t_rxtshift = TCP_MAXRXTSHIFT; 323 tcpstat.tcps_timeoutdrop++; 324 tp = tcp_drop(tp, tp->t_softerror ? 325 tp->t_softerror : ETIMEDOUT); 326 goto out; 327 } 328 tcpstat.tcps_rexmttimeo++; 329 rto = TCP_REXMTVAL(tp); 330 if (rto < tp->t_rttmin) 331 rto = tp->t_rttmin; 332 TCPT_RANGESET(tp->t_rxtcur, rto * tcp_backoff[tp->t_rxtshift], 333 tp->t_rttmin, TCPTV_REXMTMAX); 334 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 335 336 /* 337 * If we are losing and we are trying path MTU discovery, 338 * try turning it off. This will avoid black holes in 339 * the network which suppress or fail to send "packet 340 * too big" ICMP messages. We should ideally do 341 * lots more sophisticated searching to find the right 342 * value here... 343 */ 344 if (tp->t_mtudisc && tp->t_rxtshift > TCP_MAXRXTSHIFT / 6) { 345 tcpstat.tcps_pmtublackhole++; 346 347 #ifdef INET 348 /* try turning PMTUD off */ 349 if (tp->t_inpcb) 350 tp->t_mtudisc = 0; 351 #endif 352 #ifdef INET6 353 /* try using IPv6 minimum MTU */ 354 if (tp->t_in6pcb) 355 tp->t_mtudisc = 0; 356 #endif 357 358 /* XXX: more sophisticated Black hole recovery code? */ 359 } 360 361 /* 362 * If losing, let the lower level know and try for 363 * a better route. Also, if we backed off this far, 364 * our srtt estimate is probably bogus. Clobber it 365 * so we'll take the next rtt measurement as our srtt; 366 * move the current srtt into rttvar to keep the current 367 * retransmit times until then. 368 */ 369 if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { 370 #ifdef INET 371 if (tp->t_inpcb) 372 in_losing(tp->t_inpcb); 373 #endif 374 #ifdef INET6 375 if (tp->t_in6pcb) 376 in6_losing(tp->t_in6pcb); 377 #endif 378 tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); 379 tp->t_srtt = 0; 380 } 381 tp->snd_nxt = tp->snd_una; 382 tp->snd_high = tp->snd_max; 383 /* 384 * If timing a segment in this window, stop the timer. 385 */ 386 tp->t_rtttime = 0; 387 /* 388 * Remember if we are retransmitting a SYN, because if 389 * we do, set the initial congestion window must be set 390 * to 1 segment. 391 */ 392 if (tp->t_state == TCPS_SYN_SENT) 393 tp->t_flags |= TF_SYN_REXMT; 394 /* 395 * Close the congestion window down to one segment 396 * (we'll open it by one segment for each ack we get). 397 * Since we probably have a window's worth of unacked 398 * data accumulated, this "slow start" keeps us from 399 * dumping all that data as back-to-back packets (which 400 * might overwhelm an intermediate gateway). 401 * 402 * There are two phases to the opening: Initially we 403 * open by one mss on each ack. This makes the window 404 * size increase exponentially with time. If the 405 * window is larger than the path can handle, this 406 * exponential growth results in dropped packet(s) 407 * almost immediately. To get more time between 408 * drops but still "push" the network to take advantage 409 * of improving conditions, we switch from exponential 410 * to linear window opening at some threshhold size. 411 * For a threshhold, we use half the current window 412 * size, truncated to a multiple of the mss. 413 * 414 * (the minimum cwnd that will give us exponential 415 * growth is 2 mss. We don't allow the threshhold 416 * to go below this.) 417 */ 418 { 419 u_int win = min(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_segsz; 420 if (win < 2) 421 win = 2; 422 /* Loss Window MUST be one segment. */ 423 tp->snd_cwnd = tp->t_segsz; 424 tp->snd_ssthresh = win * tp->t_segsz; 425 tp->t_partialacks = -1; 426 tp->t_dupacks = 0; 427 } 428 (void) tcp_output(tp); 429 430 out: 431 #ifdef TCP_DEBUG 432 if (tp && so->so_options & SO_DEBUG) 433 tcp_trace(TA_USER, ostate, tp, NULL, 434 PRU_SLOWTIMO | (TCPT_REXMT << 8)); 435 #endif 436 splx(s); 437 } 438 439 void 440 tcp_timer_persist(void *arg) 441 { 442 struct tcpcb *tp = arg; 443 uint32_t rto; 444 int s; 445 #ifdef TCP_DEBUG 446 struct socket *so = NULL; 447 short ostate; 448 #endif 449 450 s = splsoftnet(); 451 callout_ack(&tp->t_timer[TCPT_PERSIST]); 452 if (tcp_isdead(tp)) { 453 splx(s); 454 return; 455 } 456 457 #ifdef TCP_DEBUG 458 #ifdef INET 459 if (tp->t_inpcb) 460 so = tp->t_inpcb->inp_socket; 461 #endif 462 #ifdef INET6 463 if (tp->t_in6pcb) 464 so = tp->t_in6pcb->in6p_socket; 465 #endif 466 467 ostate = tp->t_state; 468 #endif /* TCP_DEBUG */ 469 470 /* 471 * Persistance timer into zero window. 472 * Force a byte to be output, if possible. 473 */ 474 475 /* 476 * Hack: if the peer is dead/unreachable, we do not 477 * time out if the window is closed. After a full 478 * backoff, drop the connection if the idle time 479 * (no responses to probes) reaches the maximum 480 * backoff that we would use if retransmitting. 481 */ 482 rto = TCP_REXMTVAL(tp); 483 if (rto < tp->t_rttmin) 484 rto = tp->t_rttmin; 485 if (tp->t_rxtshift == TCP_MAXRXTSHIFT && 486 ((tcp_now - tp->t_rcvtime) >= tcp_maxpersistidle || 487 (tcp_now - tp->t_rcvtime) >= rto * tcp_totbackoff)) { 488 tcpstat.tcps_persistdrops++; 489 tp = tcp_drop(tp, ETIMEDOUT); 490 goto out; 491 } 492 tcpstat.tcps_persisttimeo++; 493 tcp_setpersist(tp); 494 tp->t_force = 1; 495 (void) tcp_output(tp); 496 tp->t_force = 0; 497 498 out: 499 #ifdef TCP_DEBUG 500 if (tp && so->so_options & SO_DEBUG) 501 tcp_trace(TA_USER, ostate, tp, NULL, 502 PRU_SLOWTIMO | (TCPT_PERSIST << 8)); 503 #endif 504 splx(s); 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 int s; 513 #ifdef TCP_DEBUG 514 short ostate; 515 #endif 516 517 s = splsoftnet(); 518 callout_ack(&tp->t_timer[TCPT_KEEP]); 519 if (tcp_isdead(tp)) { 520 splx(s); 521 return; 522 } 523 524 #ifdef TCP_DEBUG 525 ostate = tp->t_state; 526 #endif /* TCP_DEBUG */ 527 528 /* 529 * Keep-alive timer went off; send something 530 * or drop connection if idle for too long. 531 */ 532 533 tcpstat.tcps_keeptimeo++; 534 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 535 goto dropit; 536 #ifdef INET 537 if (tp->t_inpcb) 538 so = tp->t_inpcb->inp_socket; 539 #endif 540 #ifdef INET6 541 if (tp->t_in6pcb) 542 so = tp->t_in6pcb->in6p_socket; 543 #endif 544 if (so->so_options & SO_KEEPALIVE && 545 tp->t_state <= TCPS_CLOSE_WAIT) { 546 if ((tcp_maxidle > 0) && 547 ((tcp_now - tp->t_rcvtime) >= 548 tcp_keepidle + tcp_maxidle)) 549 goto dropit; 550 /* 551 * Send a packet designed to force a response 552 * if the peer is up and reachable: 553 * either an ACK if the connection is still alive, 554 * or an RST if the peer has closed the connection 555 * due to timeout or reboot. 556 * Using sequence number tp->snd_una-1 557 * causes the transmitted zero-length segment 558 * to lie outside the receive window; 559 * by the protocol spec, this requires the 560 * correspondent TCP to respond. 561 */ 562 tcpstat.tcps_keepprobe++; 563 if (tcp_compat_42) { 564 /* 565 * The keepalive packet must have nonzero 566 * length to get a 4.2 host to respond. 567 */ 568 (void)tcp_respond(tp, tp->t_template, 569 (struct mbuf *)NULL, NULL, tp->rcv_nxt - 1, 570 tp->snd_una - 1, 0); 571 } else { 572 (void)tcp_respond(tp, tp->t_template, 573 (struct mbuf *)NULL, NULL, tp->rcv_nxt, 574 tp->snd_una - 1, 0); 575 } 576 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepintvl); 577 } else 578 TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle); 579 580 #ifdef TCP_DEBUG 581 if (tp && so->so_options & SO_DEBUG) 582 tcp_trace(TA_USER, ostate, tp, NULL, 583 PRU_SLOWTIMO | (TCPT_KEEP << 8)); 584 #endif 585 splx(s); 586 return; 587 588 dropit: 589 tcpstat.tcps_keepdrops++; 590 (void) tcp_drop(tp, ETIMEDOUT); 591 splx(s); 592 } 593 594 void 595 tcp_timer_2msl(void *arg) 596 { 597 struct tcpcb *tp = arg; 598 int s; 599 #ifdef TCP_DEBUG 600 struct socket *so = NULL; 601 short ostate; 602 #endif 603 604 s = splsoftnet(); 605 callout_ack(&tp->t_timer[TCPT_2MSL]); 606 if (tcp_isdead(tp)) { 607 splx(s); 608 return; 609 } 610 611 /* 612 * 2 MSL timeout went off, clear the SACK scoreboard, reset 613 * the FACK estimate. 614 */ 615 tcp_free_sackholes(tp); 616 tp->snd_fack = tp->snd_una; 617 618 #ifdef TCP_DEBUG 619 #ifdef INET 620 if (tp->t_inpcb) 621 so = tp->t_inpcb->inp_socket; 622 #endif 623 #ifdef INET6 624 if (tp->t_in6pcb) 625 so = tp->t_in6pcb->in6p_socket; 626 #endif 627 628 ostate = tp->t_state; 629 #endif /* TCP_DEBUG */ 630 631 /* 632 * 2 MSL timeout in shutdown went off. If we're closed but 633 * still waiting for peer to close and connection has been idle 634 * too long, or if 2MSL time is up from TIME_WAIT, delete connection 635 * control block. Otherwise, check again in a bit. 636 */ 637 if (tp->t_state != TCPS_TIME_WAIT && 638 ((tcp_maxidle == 0) || ((tcp_now - tp->t_rcvtime) <= tcp_maxidle))) 639 TCP_TIMER_ARM(tp, TCPT_2MSL, tcp_keepintvl); 640 else 641 tp = tcp_close(tp); 642 643 #ifdef TCP_DEBUG 644 if (tp && so->so_options & SO_DEBUG) 645 tcp_trace(TA_USER, ostate, tp, NULL, 646 PRU_SLOWTIMO | (TCPT_2MSL << 8)); 647 #endif 648 splx(s); 649 } 650
Indexes created Sun Sep 21 20:09:37 GMT 2025