tcp_timer.c revision 1.93
1/* $NetBSD: tcp_timer.c,v 1.93 2018/01/19 07:53:01 ozaki-r 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 1.93 2018/01/19 07:53:01 ozaki-r Exp $"); 97 98#ifdef _KERNEL_OPT 99#include "opt_inet.h" 100#include "opt_tcp_debug.h" 101#include "opt_net_mpsafe.h" 102#endif 103 104#include <sys/param.h> 105#include <sys/systm.h> 106#include <sys/mbuf.h> 107#include <sys/socket.h> 108#include <sys/socketvar.h> 109#include <sys/protosw.h> 110#include <sys/errno.h> 111#include <sys/kernel.h> 112#include <sys/callout.h> 113#include <sys/workqueue.h> 114 115#include <net/if.h> 116 117#include <netinet/in.h> 118#include <netinet/in_systm.h> 119#include <netinet/ip.h> 120#include <netinet/in_pcb.h> 121#include <netinet/ip_var.h> 122#include <netinet/ip_icmp.h> 123 124#ifdef INET6 125#ifndef INET 126#include <netinet/in.h> 127#endif 128#include <netinet/ip6.h> 129#include <netinet6/in6_pcb.h> 130#endif 131 132#include <netinet/tcp.h> 133#include <netinet/tcp_fsm.h> 134#include <netinet/tcp_seq.h> 135#include <netinet/tcp_timer.h> 136#include <netinet/tcp_var.h> 137#include <netinet/tcp_private.h> 138#include <netinet/tcp_congctl.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 */ 148u_int tcp_keepinit = 0; 149u_int tcp_keepidle = 0; 150u_int tcp_keepintvl = 0; 151u_int tcp_keepcnt = 0; /* max idle probes */ 152 153int tcp_maxpersistidle = 0; /* max idle time in persist */ 154 155static callout_t tcp_slowtimo_ch; 156#ifdef NET_MPSAFE 157static struct workqueue *tcp_slowtimo_wq; 158static struct work tcp_slowtimo_wk; 159#endif 160 161static void tcp_slowtimo_work(struct work *, void *); 162static void tcp_slowtimo(void *); 163 164/* 165 * Time to delay the ACK. This is initialized in tcp_init(), unless 166 * its patched. 167 */ 168int tcp_delack_ticks = 0; 169 170void tcp_timer_rexmt(void *); 171void tcp_timer_persist(void *); 172void tcp_timer_keep(void *); 173void tcp_timer_2msl(void *); 174 175const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS] = { 176 tcp_timer_rexmt, 177 tcp_timer_persist, 178 tcp_timer_keep, 179 tcp_timer_2msl, 180}; 181 182/* 183 * Timer state initialization, called from tcp_init(). 184 */ 185void 186tcp_timer_init(void) 187{ 188 189 if (tcp_keepinit == 0) 190 tcp_keepinit = TCPTV_KEEP_INIT; 191 192 if (tcp_keepidle == 0) 193 tcp_keepidle = TCPTV_KEEP_IDLE; 194 195 if (tcp_keepintvl == 0) 196 tcp_keepintvl = TCPTV_KEEPINTVL; 197 198 if (tcp_keepcnt == 0) 199 tcp_keepcnt = TCPTV_KEEPCNT; 200 201 if (tcp_maxpersistidle == 0) 202 tcp_maxpersistidle = TCPTV_KEEP_IDLE; 203 204 if (tcp_delack_ticks == 0) 205 tcp_delack_ticks = TCP_DELACK_TICKS; 206} 207 208void 209tcp_slowtimo_init(void) 210{ 211#ifdef NET_MPSAFE 212 int error; 213 214 error = workqueue_create(&tcp_slowtimo_wq, "tcp_slowtimo", 215 tcp_slowtimo_work, NULL, PRI_SOFTNET, IPL_SOFTNET, WQ_MPSAFE); 216 if (error != 0) 217 panic("%s: workqueue_create failed (%d)\n", __func__, error); 218#endif 219 callout_init(&tcp_slowtimo_ch, CALLOUT_MPSAFE); 220 callout_reset(&tcp_slowtimo_ch, 1, tcp_slowtimo, NULL); 221} 222 223/* 224 * Callout to process delayed ACKs for a TCPCB. 225 */ 226void 227tcp_delack(void *arg) 228{ 229 struct tcpcb *tp = arg; 230 231 /* 232 * If tcp_output() wasn't able to transmit the ACK 233 * for whatever reason, it will restart the delayed 234 * ACK callout. 235 */ 236 237 mutex_enter(softnet_lock); 238 if ((tp->t_flags & (TF_DEAD | TF_DELACK)) != TF_DELACK) { 239 mutex_exit(softnet_lock); 240 return; 241 } 242 if (!callout_expired(&tp->t_delack_ch)) { 243 mutex_exit(softnet_lock); 244 return; 245 } 246 247 tp->t_flags |= TF_ACKNOW; 248 KERNEL_LOCK(1, NULL); 249 (void) tcp_output(tp); 250 KERNEL_UNLOCK_ONE(NULL); 251 mutex_exit(softnet_lock); 252} 253 254/* 255 * Tcp protocol timeout routine called every 500 ms. 256 * Updates the timers in all active tcb's and 257 * causes finite state machine actions if timers expire. 258 */ 259static void 260tcp_slowtimo_work(struct work *wk, void *arg) 261{ 262 263 mutex_enter(softnet_lock); 264 tcp_iss_seq += TCP_ISSINCR; /* increment iss */ 265 tcp_now++; /* for timestamps */ 266 mutex_exit(softnet_lock); 267 268 callout_schedule(&tcp_slowtimo_ch, hz / PR_SLOWHZ); 269} 270 271static void 272tcp_slowtimo(void *arg) 273{ 274 275#ifdef NET_MPSAFE 276 workqueue_enqueue(tcp_slowtimo_wq, &tcp_slowtimo_wk, NULL); 277#else 278 tcp_slowtimo_work(NULL, NULL); 279#endif 280} 281 282/* 283 * Cancel all timers for TCP tp. 284 */ 285void 286tcp_canceltimers(struct tcpcb *tp) 287{ 288 int i; 289 290 for (i = 0; i < TCPT_NTIMERS; i++) 291 TCP_TIMER_DISARM(tp, i); 292} 293 294const int tcp_backoff[TCP_MAXRXTSHIFT + 1] = 295 { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 }; 296 297const int tcp_totbackoff = 511; /* sum of tcp_backoff[] */ 298 299/* 300 * TCP timer processing. 301 */ 302 303void 304tcp_timer_rexmt(void *arg) 305{ 306 struct tcpcb *tp = arg; 307 uint32_t rto; 308#ifdef TCP_DEBUG 309 struct socket *so = NULL; 310 short ostate; 311#endif 312 313 mutex_enter(softnet_lock); 314 if ((tp->t_flags & TF_DEAD) != 0) { 315 mutex_exit(softnet_lock); 316 return; 317 } 318 if (!callout_expired(&tp->t_timer[TCPT_REXMT])) { 319 mutex_exit(softnet_lock); 320 return; 321 } 322 323 KERNEL_LOCK(1, NULL); 324 if ((tp->t_flags & TF_PMTUD_PEND) && tp->t_inpcb && 325 SEQ_GEQ(tp->t_pmtud_th_seq, tp->snd_una) && 326 SEQ_LT(tp->t_pmtud_th_seq, (int)(tp->snd_una + tp->t_ourmss))) { 327 extern struct sockaddr_in icmpsrc; 328 struct icmp icmp; 329 330 tp->t_flags &= ~TF_PMTUD_PEND; 331 332 /* XXX create fake icmp message with relevant entries */ 333 icmp.icmp_nextmtu = tp->t_pmtud_nextmtu; 334 icmp.icmp_ip.ip_len = tp->t_pmtud_ip_len; 335 icmp.icmp_ip.ip_hl = tp->t_pmtud_ip_hl; 336 icmpsrc.sin_addr = tp->t_inpcb->inp_faddr; 337 icmp_mtudisc(&icmp, icmpsrc.sin_addr); 338 339 /* 340 * Notify all connections to the same peer about 341 * new mss and trigger retransmit. 342 */ 343 in_pcbnotifyall(&tcbtable, icmpsrc.sin_addr, EMSGSIZE, 344 tcp_mtudisc); 345 KERNEL_UNLOCK_ONE(NULL); 346 mutex_exit(softnet_lock); 347 return; 348 } 349#ifdef TCP_DEBUG 350#ifdef INET 351 if (tp->t_inpcb) 352 so = tp->t_inpcb->inp_socket; 353#endif 354#ifdef INET6 355 if (tp->t_in6pcb) 356 so = tp->t_in6pcb->in6p_socket; 357#endif 358 ostate = tp->t_state; 359#endif /* TCP_DEBUG */ 360 361 /* 362 * Clear the SACK scoreboard, reset FACK estimate. 363 */ 364 tcp_free_sackholes(tp); 365 tp->snd_fack = tp->snd_una; 366 367 /* 368 * Retransmission timer went off. Message has not 369 * been acked within retransmit interval. Back off 370 * to a longer retransmit interval and retransmit one segment. 371 */ 372 373 if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { 374 tp->t_rxtshift = TCP_MAXRXTSHIFT; 375 TCP_STATINC(TCP_STAT_TIMEOUTDROP); 376 tp = tcp_drop(tp, tp->t_softerror ? 377 tp->t_softerror : ETIMEDOUT); 378 goto out; 379 } 380 TCP_STATINC(TCP_STAT_REXMTTIMEO); 381 rto = TCP_REXMTVAL(tp); 382 if (rto < tp->t_rttmin) 383 rto = tp->t_rttmin; 384 TCPT_RANGESET(tp->t_rxtcur, rto * tcp_backoff[tp->t_rxtshift], 385 tp->t_rttmin, TCPTV_REXMTMAX); 386 TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); 387 388 /* 389 * If we are losing and we are trying path MTU discovery, 390 * try turning it off. This will avoid black holes in 391 * the network which suppress or fail to send "packet 392 * too big" ICMP messages. We should ideally do 393 * lots more sophisticated searching to find the right 394 * value here... 395 */ 396 if (tp->t_mtudisc && tp->t_rxtshift > TCP_MAXRXTSHIFT / 6) { 397 TCP_STATINC(TCP_STAT_PMTUBLACKHOLE); 398 399#ifdef INET 400 /* try turning PMTUD off */ 401 if (tp->t_inpcb) 402 tp->t_mtudisc = 0; 403#endif 404#ifdef INET6 405 /* try using IPv6 minimum MTU */ 406 if (tp->t_in6pcb) 407 tp->t_mtudisc = 0; 408#endif 409 410 /* XXX: more sophisticated Black hole recovery code? */ 411 } 412 413 /* 414 * If losing, let the lower level know and try for 415 * a better route. Also, if we backed off this far, 416 * our srtt estimate is probably bogus. Clobber it 417 * so we'll take the next rtt measurement as our srtt; 418 * move the current srtt into rttvar to keep the current 419 * retransmit times until then. 420 */ 421 if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { 422#ifdef INET 423 if (tp->t_inpcb) 424 in_losing(tp->t_inpcb); 425#endif 426#ifdef INET6 427 if (tp->t_in6pcb) 428 in6_losing(tp->t_in6pcb); 429#endif 430 /* 431 * This operation is not described in RFC2988. The 432 * point is to keep srtt+4*rttvar constant, so we 433 * should shift right 2 bits to divide by 4, and then 434 * shift right one bit because the storage 435 * representation of rttvar is 1/16s vs 1/32s for 436 * srtt. 437 */ 438 tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); 439 tp->t_srtt = 0; 440 } 441 tp->snd_nxt = tp->snd_una; 442 tp->snd_high = tp->snd_max; 443 /* 444 * If timing a segment in this window, stop the timer. 445 */ 446 tp->t_rtttime = 0; 447 /* 448 * Remember if we are retransmitting a SYN, because if 449 * we do, set the initial congestion window must be set 450 * to 1 segment. 451 */ 452 if (tp->t_state == TCPS_SYN_SENT) 453 tp->t_flags |= TF_SYN_REXMT; 454 455 /* 456 * Adjust congestion control parameters. 457 */ 458 tp->t_congctl->slow_retransmit(tp); 459 460 (void) tcp_output(tp); 461 462 out: 463#ifdef TCP_DEBUG 464 if (tp && so->so_options & SO_DEBUG) 465 tcp_trace(TA_USER, ostate, tp, NULL, 466 PRU_SLOWTIMO | (TCPT_REXMT << 8)); 467#endif 468 KERNEL_UNLOCK_ONE(NULL); 469 mutex_exit(softnet_lock); 470} 471 472void 473tcp_timer_persist(void *arg) 474{ 475 struct tcpcb *tp = arg; 476 uint32_t rto; 477#ifdef TCP_DEBUG 478 struct socket *so = NULL; 479 short ostate; 480#endif 481 482 mutex_enter(softnet_lock); 483 if ((tp->t_flags & TF_DEAD) != 0) { 484 mutex_exit(softnet_lock); 485 return; 486 } 487 if (!callout_expired(&tp->t_timer[TCPT_PERSIST])) { 488 mutex_exit(softnet_lock); 489 return; 490 } 491 492 KERNEL_LOCK(1, NULL); 493#ifdef TCP_DEBUG 494#ifdef INET 495 if (tp->t_inpcb) 496 so = tp->t_inpcb->inp_socket; 497#endif 498#ifdef INET6 499 if (tp->t_in6pcb) 500 so = tp->t_in6pcb->in6p_socket; 501#endif 502 503 ostate = tp->t_state; 504#endif /* TCP_DEBUG */ 505 506 /* 507 * Persistance timer into zero window. 508 * Force a byte to be output, if possible. 509 */ 510 511 /* 512 * Hack: if the peer is dead/unreachable, we do not 513 * time out if the window is closed. After a full 514 * backoff, drop the connection if the idle time 515 * (no responses to probes) reaches the maximum 516 * backoff that we would use if retransmitting. 517 */ 518 rto = TCP_REXMTVAL(tp); 519 if (rto < tp->t_rttmin) 520 rto = tp->t_rttmin; 521 if (tp->t_rxtshift == TCP_MAXRXTSHIFT && 522 ((tcp_now - tp->t_rcvtime) >= tcp_maxpersistidle || 523 (tcp_now - tp->t_rcvtime) >= rto * tcp_totbackoff)) { 524 TCP_STATINC(TCP_STAT_PERSISTDROPS); 525 tp = tcp_drop(tp, ETIMEDOUT); 526 goto out; 527 } 528 TCP_STATINC(TCP_STAT_PERSISTTIMEO); 529 tcp_setpersist(tp); 530 tp->t_force = 1; 531 (void) tcp_output(tp); 532 tp->t_force = 0; 533 534 out: 535#ifdef TCP_DEBUG 536 if (tp && so->so_options & SO_DEBUG) 537 tcp_trace(TA_USER, ostate, tp, NULL, 538 PRU_SLOWTIMO | (TCPT_PERSIST << 8)); 539#endif 540 KERNEL_UNLOCK_ONE(NULL); 541 mutex_exit(softnet_lock); 542} 543 544void 545tcp_timer_keep(void *arg) 546{ 547 struct tcpcb *tp = arg; 548 struct socket *so = NULL; /* Quell compiler warning */ 549#ifdef TCP_DEBUG 550 short ostate; 551#endif 552 553 mutex_enter(softnet_lock); 554 if ((tp->t_flags & TF_DEAD) != 0) { 555 mutex_exit(softnet_lock); 556 return; 557 } 558 if (!callout_expired(&tp->t_timer[TCPT_KEEP])) { 559 mutex_exit(softnet_lock); 560 return; 561 } 562 563 KERNEL_LOCK(1, NULL); 564 565#ifdef TCP_DEBUG 566 ostate = tp->t_state; 567#endif /* TCP_DEBUG */ 568 569 /* 570 * Keep-alive timer went off; send something 571 * or drop connection if idle for too long. 572 */ 573 574 TCP_STATINC(TCP_STAT_KEEPTIMEO); 575 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 576 goto dropit; 577#ifdef INET 578 if (tp->t_inpcb) 579 so = tp->t_inpcb->inp_socket; 580#endif 581#ifdef INET6 582 if (tp->t_in6pcb) 583 so = tp->t_in6pcb->in6p_socket; 584#endif 585 KASSERT(so != NULL); 586 if (so->so_options & SO_KEEPALIVE && 587 tp->t_state <= TCPS_CLOSE_WAIT) { 588 if ((tp->t_maxidle > 0) && 589 ((tcp_now - tp->t_rcvtime) >= 590 tp->t_keepidle + tp->t_maxidle)) 591 goto dropit; 592 /* 593 * Send a packet designed to force a response 594 * if the peer is up and reachable: 595 * either an ACK if the connection is still alive, 596 * or an RST if the peer has closed the connection 597 * due to timeout or reboot. 598 * Using sequence number tp->snd_una-1 599 * causes the transmitted zero-length segment 600 * to lie outside the receive window; 601 * by the protocol spec, this requires the 602 * correspondent TCP to respond. 603 */ 604 TCP_STATINC(TCP_STAT_KEEPPROBE); 605 606 (void)tcp_respond(tp, tp->t_template, 607 NULL, NULL, tp->rcv_nxt, 608 tp->snd_una - 1, 0); 609 610 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepintvl); 611 } else 612 TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepidle); 613 614#ifdef TCP_DEBUG 615 if (tp && so->so_options & SO_DEBUG) 616 tcp_trace(TA_USER, ostate, tp, NULL, 617 PRU_SLOWTIMO | (TCPT_KEEP << 8)); 618#endif 619 KERNEL_UNLOCK_ONE(NULL); 620 mutex_exit(softnet_lock); 621 return; 622 623 dropit: 624 TCP_STATINC(TCP_STAT_KEEPDROPS); 625 (void) tcp_drop(tp, ETIMEDOUT); 626 KERNEL_UNLOCK_ONE(NULL); 627 mutex_exit(softnet_lock); 628} 629 630void 631tcp_timer_2msl(void *arg) 632{ 633 struct tcpcb *tp = arg; 634#ifdef TCP_DEBUG 635 struct socket *so = NULL; 636 short ostate; 637#endif 638 639 mutex_enter(softnet_lock); 640 if ((tp->t_flags & TF_DEAD) != 0) { 641 mutex_exit(softnet_lock); 642 return; 643 } 644 if (!callout_expired(&tp->t_timer[TCPT_2MSL])) { 645 mutex_exit(softnet_lock); 646 return; 647 } 648 649 /* 650 * 2 MSL timeout went off, clear the SACK scoreboard, reset 651 * the FACK estimate. 652 */ 653 KERNEL_LOCK(1, NULL); 654 tcp_free_sackholes(tp); 655 tp->snd_fack = tp->snd_una; 656 657#ifdef TCP_DEBUG 658#ifdef INET 659 if (tp->t_inpcb) 660 so = tp->t_inpcb->inp_socket; 661#endif 662#ifdef INET6 663 if (tp->t_in6pcb) 664 so = tp->t_in6pcb->in6p_socket; 665#endif 666 667 ostate = tp->t_state; 668#endif /* TCP_DEBUG */ 669 670 /* 671 * 2 MSL timeout in shutdown went off. If we're closed but 672 * still waiting for peer to close and connection has been idle 673 * too long, or if 2MSL time is up from TIME_WAIT, delete connection 674 * control block. Otherwise, check again in a bit. 675 */ 676 if (tp->t_state != TCPS_TIME_WAIT && 677 ((tp->t_maxidle == 0) || 678 ((tcp_now - tp->t_rcvtime) <= tp->t_maxidle))) 679 TCP_TIMER_ARM(tp, TCPT_2MSL, tp->t_keepintvl); 680 else 681 tp = tcp_close(tp); 682 683#ifdef TCP_DEBUG 684 if (tp && so->so_options & SO_DEBUG) 685 tcp_trace(TA_USER, ostate, tp, NULL, 686 PRU_SLOWTIMO | (TCPT_2MSL << 8)); 687#endif 688 KERNEL_UNLOCK_ONE(NULL); 689 mutex_exit(softnet_lock); 690} 691