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sys/netinet/tcp_timer.c
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1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tcp_timer.c 8.2 (Berkeley) 5/24/95 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD: releng/9.1/sys/netinet/tcp_timer.c 232945 2012-03-13 20:37:57Z glebius $"); 34 35 #include "opt_inet6.h" 36 #include "opt_tcpdebug.h" 37 38 #include <sys/param.h> 39 #include <sys/kernel.h> 40 #include <sys/lock.h> 41 #include <sys/mbuf.h> 42 #include <sys/mutex.h> 43 #include <sys/protosw.h> 44 #include <sys/smp.h> 45 #include <sys/socket.h> 46 #include <sys/socketvar.h> 47 #include <sys/sysctl.h> 48 #include <sys/systm.h> 49 50 #include <net/if.h> 51 #include <net/route.h> 52 #include <net/vnet.h> 53 54 #include <netinet/cc.h> 55 #include <netinet/in.h> 56 #include <netinet/in_pcb.h> 57 #include <netinet/in_systm.h> 58 #ifdef INET6 59 #include <netinet6/in6_pcb.h> 60 #endif 61 #include <netinet/ip_var.h> 62 #include <netinet/tcp_fsm.h> 63 #include <netinet/tcp_timer.h> 64 #include <netinet/tcp_var.h> 65 #include <netinet/tcpip.h> 66 #ifdef TCPDEBUG 67 #include <netinet/tcp_debug.h> 68 #endif 69 70 int tcp_keepinit; 71 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit, CTLTYPE_INT|CTLFLAG_RW, 72 &tcp_keepinit, 0, sysctl_msec_to_ticks, "I", "time to establish connection"); 73 74 int tcp_keepidle; 75 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle, CTLTYPE_INT|CTLFLAG_RW, 76 &tcp_keepidle, 0, sysctl_msec_to_ticks, "I", "time before keepalive probes begin"); 77 78 int tcp_keepintvl; 79 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl, CTLTYPE_INT|CTLFLAG_RW, 80 &tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", "time between keepalive probes"); 81 82 int tcp_delacktime; 83 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DELACKTIME, delacktime, CTLTYPE_INT|CTLFLAG_RW, 84 &tcp_delacktime, 0, sysctl_msec_to_ticks, "I", 85 "Time before a delayed ACK is sent"); 86 87 int tcp_msl; 88 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl, CTLTYPE_INT|CTLFLAG_RW, 89 &tcp_msl, 0, sysctl_msec_to_ticks, "I", "Maximum segment lifetime"); 90 91 int tcp_rexmit_min; 92 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_min, CTLTYPE_INT|CTLFLAG_RW, 93 &tcp_rexmit_min, 0, sysctl_msec_to_ticks, "I", 94 "Minimum Retransmission Timeout"); 95 96 int tcp_rexmit_slop; 97 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_slop, CTLTYPE_INT|CTLFLAG_RW, 98 &tcp_rexmit_slop, 0, sysctl_msec_to_ticks, "I", 99 "Retransmission Timer Slop"); 100 101 static int always_keepalive = 1; 102 SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive, CTLFLAG_RW, 103 &always_keepalive , 0, "Assume SO_KEEPALIVE on all TCP connections"); 104 105 int tcp_fast_finwait2_recycle = 0; 106 SYSCTL_INT(_net_inet_tcp, OID_AUTO, fast_finwait2_recycle, CTLFLAG_RW, 107 &tcp_fast_finwait2_recycle, 0, 108 "Recycle closed FIN_WAIT_2 connections faster"); 109 110 int tcp_finwait2_timeout; 111 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, finwait2_timeout, CTLTYPE_INT|CTLFLAG_RW, 112 &tcp_finwait2_timeout, 0, sysctl_msec_to_ticks, "I", "FIN-WAIT2 timeout"); 113 114 int tcp_keepcnt = TCPTV_KEEPCNT; 115 SYSCTL_INT(_net_inet_tcp, OID_AUTO, keepcnt, CTLFLAG_RW, &tcp_keepcnt, 0, 116 "Number of keepalive probes to send"); 117 118 /* max idle probes */ 119 int tcp_maxpersistidle; 120 121 static int per_cpu_timers = 0; 122 SYSCTL_INT(_net_inet_tcp, OID_AUTO, per_cpu_timers, CTLFLAG_RW, 123 &per_cpu_timers , 0, "run tcp timers on all cpus"); 124 125 #define INP_CPU(inp) (per_cpu_timers ? (!CPU_ABSENT(((inp)->inp_flowid % (mp_maxid+1))) ? \ 126 ((inp)->inp_flowid % (mp_maxid+1)) : curcpu) : 0) 127 128 /* 129 * Tcp protocol timeout routine called every 500 ms. 130 * Updates timestamps used for TCP 131 * causes finite state machine actions if timers expire. 132 */ 133 void 134 tcp_slowtimo(void) 135 { 136 VNET_ITERATOR_DECL(vnet_iter); 137 138 VNET_LIST_RLOCK_NOSLEEP(); 139 VNET_FOREACH(vnet_iter) { 140 CURVNET_SET(vnet_iter); 141 INP_INFO_WLOCK(&V_tcbinfo); 142 (void) tcp_tw_2msl_scan(0); 143 INP_INFO_WUNLOCK(&V_tcbinfo); 144 CURVNET_RESTORE(); 145 } 146 VNET_LIST_RUNLOCK_NOSLEEP(); 147 } 148 149 int tcp_syn_backoff[TCP_MAXRXTSHIFT + 1] = 150 { 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 64, 64 }; 151 152 int tcp_backoff[TCP_MAXRXTSHIFT + 1] = 153 { 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 512, 512, 512 }; 154 155 static int tcp_totbackoff = 2559; /* sum of tcp_backoff[] */ 156 157 static int tcp_timer_race; 158 SYSCTL_INT(_net_inet_tcp, OID_AUTO, timer_race, CTLFLAG_RD, &tcp_timer_race, 159 0, "Count of t_inpcb races on tcp_discardcb"); 160 161 /* 162 * TCP timer processing. 163 */ 164 165 void 166 tcp_timer_delack(void *xtp) 167 { 168 struct tcpcb *tp = xtp; 169 struct inpcb *inp; 170 CURVNET_SET(tp->t_vnet); 171 172 inp = tp->t_inpcb; 173 /* 174 * XXXRW: While this assert is in fact correct, bugs in the tcpcb 175 * tear-down mean we need it as a work-around for races between 176 * timers and tcp_discardcb(). 177 * 178 * KASSERT(inp != NULL, ("tcp_timer_delack: inp == NULL")); 179 */ 180 if (inp == NULL) { 181 tcp_timer_race++; 182 CURVNET_RESTORE(); 183 return; 184 } 185 INP_WLOCK(inp); 186 if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_delack) 187 || !callout_active(&tp->t_timers->tt_delack)) { 188 INP_WUNLOCK(inp); 189 CURVNET_RESTORE(); 190 return; 191 } 192 callout_deactivate(&tp->t_timers->tt_delack); 193 194 tp->t_flags |= TF_ACKNOW; 195 TCPSTAT_INC(tcps_delack); 196 (void) tcp_output(tp); 197 INP_WUNLOCK(inp); 198 CURVNET_RESTORE(); 199 } 200 201 void 202 tcp_timer_2msl(void *xtp) 203 { 204 struct tcpcb *tp = xtp; 205 struct inpcb *inp; 206 CURVNET_SET(tp->t_vnet); 207 #ifdef TCPDEBUG 208 int ostate; 209 210 ostate = tp->t_state; 211 #endif 212 /* 213 * XXXRW: Does this actually happen? 214 */ 215 INP_INFO_WLOCK(&V_tcbinfo); 216 inp = tp->t_inpcb; 217 /* 218 * XXXRW: While this assert is in fact correct, bugs in the tcpcb 219 * tear-down mean we need it as a work-around for races between 220 * timers and tcp_discardcb(). 221 * 222 * KASSERT(inp != NULL, ("tcp_timer_2msl: inp == NULL")); 223 */ 224 if (inp == NULL) { 225 tcp_timer_race++; 226 INP_INFO_WUNLOCK(&V_tcbinfo); 227 CURVNET_RESTORE(); 228 return; 229 } 230 INP_WLOCK(inp); 231 tcp_free_sackholes(tp); 232 if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_2msl) || 233 !callout_active(&tp->t_timers->tt_2msl)) { 234 INP_WUNLOCK(tp->t_inpcb); 235 INP_INFO_WUNLOCK(&V_tcbinfo); 236 CURVNET_RESTORE(); 237 return; 238 } 239 callout_deactivate(&tp->t_timers->tt_2msl); 240 /* 241 * 2 MSL timeout in shutdown went off. If we're closed but 242 * still waiting for peer to close and connection has been idle 243 * too long, or if 2MSL time is up from TIME_WAIT, delete connection 244 * control block. Otherwise, check again in a bit. 245 * 246 * If fastrecycle of FIN_WAIT_2, in FIN_WAIT_2 and receiver has closed, 247 * there's no point in hanging onto FIN_WAIT_2 socket. Just close it. 248 * Ignore fact that there were recent incoming segments. 249 */ 250 if (tcp_fast_finwait2_recycle && tp->t_state == TCPS_FIN_WAIT_2 && 251 tp->t_inpcb && tp->t_inpcb->inp_socket && 252 (tp->t_inpcb->inp_socket->so_rcv.sb_state & SBS_CANTRCVMORE)) { 253 TCPSTAT_INC(tcps_finwait2_drops); 254 tp = tcp_close(tp); 255 } else { 256 if (tp->t_state != TCPS_TIME_WAIT && 257 ticks - tp->t_rcvtime <= TP_MAXIDLE(tp)) 258 callout_reset_on(&tp->t_timers->tt_2msl, 259 TP_KEEPINTVL(tp), tcp_timer_2msl, tp, INP_CPU(inp)); 260 else 261 tp = tcp_close(tp); 262 } 263 264 #ifdef TCPDEBUG 265 if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 266 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, 267 PRU_SLOWTIMO); 268 #endif 269 if (tp != NULL) 270 INP_WUNLOCK(inp); 271 INP_INFO_WUNLOCK(&V_tcbinfo); 272 CURVNET_RESTORE(); 273 } 274 275 void 276 tcp_timer_keep(void *xtp) 277 { 278 struct tcpcb *tp = xtp; 279 struct tcptemp *t_template; 280 struct inpcb *inp; 281 CURVNET_SET(tp->t_vnet); 282 #ifdef TCPDEBUG 283 int ostate; 284 285 ostate = tp->t_state; 286 #endif 287 INP_INFO_WLOCK(&V_tcbinfo); 288 inp = tp->t_inpcb; 289 /* 290 * XXXRW: While this assert is in fact correct, bugs in the tcpcb 291 * tear-down mean we need it as a work-around for races between 292 * timers and tcp_discardcb(). 293 * 294 * KASSERT(inp != NULL, ("tcp_timer_keep: inp == NULL")); 295 */ 296 if (inp == NULL) { 297 tcp_timer_race++; 298 INP_INFO_WUNLOCK(&V_tcbinfo); 299 CURVNET_RESTORE(); 300 return; 301 } 302 INP_WLOCK(inp); 303 if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_keep) 304 || !callout_active(&tp->t_timers->tt_keep)) { 305 INP_WUNLOCK(inp); 306 INP_INFO_WUNLOCK(&V_tcbinfo); 307 CURVNET_RESTORE(); 308 return; 309 } 310 callout_deactivate(&tp->t_timers->tt_keep); 311 /* 312 * Keep-alive timer went off; send something 313 * or drop connection if idle for too long. 314 */ 315 TCPSTAT_INC(tcps_keeptimeo); 316 if (tp->t_state < TCPS_ESTABLISHED) 317 goto dropit; 318 if ((always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) && 319 tp->t_state <= TCPS_CLOSING) { 320 if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp)) 321 goto dropit; 322 /* 323 * Send a packet designed to force a response 324 * if the peer is up and reachable: 325 * either an ACK if the connection is still alive, 326 * or an RST if the peer has closed the connection 327 * due to timeout or reboot. 328 * Using sequence number tp->snd_una-1 329 * causes the transmitted zero-length segment 330 * to lie outside the receive window; 331 * by the protocol spec, this requires the 332 * correspondent TCP to respond. 333 */ 334 TCPSTAT_INC(tcps_keepprobe); 335 t_template = tcpip_maketemplate(inp); 336 if (t_template) { 337 tcp_respond(tp, t_template->tt_ipgen, 338 &t_template->tt_t, (struct mbuf *)NULL, 339 tp->rcv_nxt, tp->snd_una - 1, 0); 340 free(t_template, M_TEMP); 341 } 342 callout_reset_on(&tp->t_timers->tt_keep, TP_KEEPINTVL(tp), 343 tcp_timer_keep, tp, INP_CPU(inp)); 344 } else 345 callout_reset_on(&tp->t_timers->tt_keep, TP_KEEPIDLE(tp), 346 tcp_timer_keep, tp, INP_CPU(inp)); 347 348 #ifdef TCPDEBUG 349 if (inp->inp_socket->so_options & SO_DEBUG) 350 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, 351 PRU_SLOWTIMO); 352 #endif 353 INP_WUNLOCK(inp); 354 INP_INFO_WUNLOCK(&V_tcbinfo); 355 CURVNET_RESTORE(); 356 return; 357 358 dropit: 359 TCPSTAT_INC(tcps_keepdrops); 360 tp = tcp_drop(tp, ETIMEDOUT); 361 362 #ifdef TCPDEBUG 363 if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 364 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, 365 PRU_SLOWTIMO); 366 #endif 367 if (tp != NULL) 368 INP_WUNLOCK(tp->t_inpcb); 369 INP_INFO_WUNLOCK(&V_tcbinfo); 370 CURVNET_RESTORE(); 371 } 372 373 void 374 tcp_timer_persist(void *xtp) 375 { 376 struct tcpcb *tp = xtp; 377 struct inpcb *inp; 378 CURVNET_SET(tp->t_vnet); 379 #ifdef TCPDEBUG 380 int ostate; 381 382 ostate = tp->t_state; 383 #endif 384 INP_INFO_WLOCK(&V_tcbinfo); 385 inp = tp->t_inpcb; 386 /* 387 * XXXRW: While this assert is in fact correct, bugs in the tcpcb 388 * tear-down mean we need it as a work-around for races between 389 * timers and tcp_discardcb(). 390 * 391 * KASSERT(inp != NULL, ("tcp_timer_persist: inp == NULL")); 392 */ 393 if (inp == NULL) { 394 tcp_timer_race++; 395 INP_INFO_WUNLOCK(&V_tcbinfo); 396 CURVNET_RESTORE(); 397 return; 398 } 399 INP_WLOCK(inp); 400 if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_persist) 401 || !callout_active(&tp->t_timers->tt_persist)) { 402 INP_WUNLOCK(inp); 403 INP_INFO_WUNLOCK(&V_tcbinfo); 404 CURVNET_RESTORE(); 405 return; 406 } 407 callout_deactivate(&tp->t_timers->tt_persist); 408 /* 409 * Persistance timer into zero window. 410 * Force a byte to be output, if possible. 411 */ 412 TCPSTAT_INC(tcps_persisttimeo); 413 /* 414 * Hack: if the peer is dead/unreachable, we do not 415 * time out if the window is closed. After a full 416 * backoff, drop the connection if the idle time 417 * (no responses to probes) reaches the maximum 418 * backoff that we would use if retransmitting. 419 */ 420 if (tp->t_rxtshift == TCP_MAXRXTSHIFT && 421 (ticks - tp->t_rcvtime >= tcp_maxpersistidle || 422 ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) { 423 TCPSTAT_INC(tcps_persistdrop); 424 tp = tcp_drop(tp, ETIMEDOUT); 425 goto out; 426 } 427 tcp_setpersist(tp); 428 tp->t_flags |= TF_FORCEDATA; 429 (void) tcp_output(tp); 430 tp->t_flags &= ~TF_FORCEDATA; 431 432 out: 433 #ifdef TCPDEBUG 434 if (tp != NULL && tp->t_inpcb->inp_socket->so_options & SO_DEBUG) 435 tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO); 436 #endif 437 if (tp != NULL) 438 INP_WUNLOCK(inp); 439 INP_INFO_WUNLOCK(&V_tcbinfo); 440 CURVNET_RESTORE(); 441 } 442 443 void 444 tcp_timer_rexmt(void * xtp) 445 { 446 struct tcpcb *tp = xtp; 447 CURVNET_SET(tp->t_vnet); 448 int rexmt; 449 int headlocked; 450 struct inpcb *inp; 451 #ifdef TCPDEBUG 452 int ostate; 453 454 ostate = tp->t_state; 455 #endif 456 INP_INFO_RLOCK(&V_tcbinfo); 457 inp = tp->t_inpcb; 458 /* 459 * XXXRW: While this assert is in fact correct, bugs in the tcpcb 460 * tear-down mean we need it as a work-around for races between 461 * timers and tcp_discardcb(). 462 * 463 * KASSERT(inp != NULL, ("tcp_timer_rexmt: inp == NULL")); 464 */ 465 if (inp == NULL) { 466 tcp_timer_race++; 467 INP_INFO_RUNLOCK(&V_tcbinfo); 468 CURVNET_RESTORE(); 469 return; 470 } 471 INP_WLOCK(inp); 472 if ((inp->inp_flags & INP_DROPPED) || callout_pending(&tp->t_timers->tt_rexmt) 473 || !callout_active(&tp->t_timers->tt_rexmt)) { 474 INP_WUNLOCK(inp); 475 INP_INFO_RUNLOCK(&V_tcbinfo); 476 CURVNET_RESTORE(); 477 return; 478 } 479 callout_deactivate(&tp->t_timers->tt_rexmt); 480 tcp_free_sackholes(tp); 481 /* 482 * Retransmission timer went off. Message has not 483 * been acked within retransmit interval. Back off 484 * to a longer retransmit interval and retransmit one segment. 485 */ 486 if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { 487 tp->t_rxtshift = TCP_MAXRXTSHIFT; 488 TCPSTAT_INC(tcps_timeoutdrop); 489 in_pcbref(inp); 490 INP_INFO_RUNLOCK(&V_tcbinfo); 491 INP_WUNLOCK(inp); 492 INP_INFO_WLOCK(&V_tcbinfo); 493 INP_WLOCK(inp); 494 if (in_pcbrele_wlocked(inp)) { 495 INP_INFO_WUNLOCK(&V_tcbinfo); 496 CURVNET_RESTORE(); 497 return; 498 } 499 if (inp->inp_flags & INP_DROPPED) { 500 INP_WUNLOCK(inp); 501 INP_INFO_WUNLOCK(&V_tcbinfo); 502 CURVNET_RESTORE(); 503 return; 504 } 505 506 tp = tcp_drop(tp, tp->t_softerror ? 507 tp->t_softerror : ETIMEDOUT); 508 headlocked = 1; 509 goto out; 510 } 511 INP_INFO_RUNLOCK(&V_tcbinfo); 512 headlocked = 0; 513 if (tp->t_rxtshift == 1) { 514 /* 515 * first retransmit; record ssthresh and cwnd so they can 516 * be recovered if this turns out to be a "bad" retransmit. 517 * A retransmit is considered "bad" if an ACK for this 518 * segment is received within RTT/2 interval; the assumption 519 * here is that the ACK was already in flight. See 520 * "On Estimating End-to-End Network Path Properties" by 521 * Allman and Paxson for more details. 522 */ 523 tp->snd_cwnd_prev = tp->snd_cwnd; 524 tp->snd_ssthresh_prev = tp->snd_ssthresh; 525 tp->snd_recover_prev = tp->snd_recover; 526 if (IN_FASTRECOVERY(tp->t_flags)) 527 tp->t_flags |= TF_WASFRECOVERY; 528 else 529 tp->t_flags &= ~TF_WASFRECOVERY; 530 if (IN_CONGRECOVERY(tp->t_flags)) 531 tp->t_flags |= TF_WASCRECOVERY; 532 else 533 tp->t_flags &= ~TF_WASCRECOVERY; 534 tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1)); 535 tp->t_flags |= TF_PREVVALID; 536 } else 537 tp->t_flags &= ~TF_PREVVALID; 538 TCPSTAT_INC(tcps_rexmttimeo); 539 if (tp->t_state == TCPS_SYN_SENT) 540 rexmt = TCP_REXMTVAL(tp) * tcp_syn_backoff[tp->t_rxtshift]; 541 else 542 rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift]; 543 TCPT_RANGESET(tp->t_rxtcur, rexmt, 544 tp->t_rttmin, TCPTV_REXMTMAX); 545 /* 546 * Disable rfc1323 if we haven't got any response to 547 * our third SYN to work-around some broken terminal servers 548 * (most of which have hopefully been retired) that have bad VJ 549 * header compression code which trashes TCP segments containing 550 * unknown-to-them TCP options. 551 */ 552 if ((tp->t_state == TCPS_SYN_SENT) && (tp->t_rxtshift == 3)) 553 tp->t_flags &= ~(TF_REQ_SCALE|TF_REQ_TSTMP); 554 /* 555 * If we backed off this far, our srtt estimate is probably bogus. 556 * Clobber it so we'll take the next rtt measurement as our srtt; 557 * move the current srtt into rttvar to keep the current 558 * retransmit times until then. 559 */ 560 if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { 561 #ifdef INET6 562 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) 563 in6_losing(tp->t_inpcb); 564 else 565 #endif 566 tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); 567 tp->t_srtt = 0; 568 } 569 tp->snd_nxt = tp->snd_una; 570 tp->snd_recover = tp->snd_max; 571 /* 572 * Force a segment to be sent. 573 */ 574 tp->t_flags |= TF_ACKNOW; 575 /* 576 * If timing a segment in this window, stop the timer. 577 */ 578 tp->t_rtttime = 0; 579 580 cc_cong_signal(tp, NULL, CC_RTO); 581 582 (void) tcp_output(tp); 583 584 out: 585 #ifdef TCPDEBUG 586 if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 587 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, 588 PRU_SLOWTIMO); 589 #endif 590 if (tp != NULL) 591 INP_WUNLOCK(inp); 592 if (headlocked) 593 INP_INFO_WUNLOCK(&V_tcbinfo); 594 CURVNET_RESTORE(); 595 } 596 597 void 598 tcp_timer_activate(struct tcpcb *tp, int timer_type, u_int delta) 599 { 600 struct callout *t_callout; 601 void *f_callout; 602 struct inpcb *inp = tp->t_inpcb; 603 int cpu = INP_CPU(inp); 604 605 switch (timer_type) { 606 case TT_DELACK: 607 t_callout = &tp->t_timers->tt_delack; 608 f_callout = tcp_timer_delack; 609 break; 610 case TT_REXMT: 611 t_callout = &tp->t_timers->tt_rexmt; 612 f_callout = tcp_timer_rexmt; 613 break; 614 case TT_PERSIST: 615 t_callout = &tp->t_timers->tt_persist; 616 f_callout = tcp_timer_persist; 617 break; 618 case TT_KEEP: 619 t_callout = &tp->t_timers->tt_keep; 620 f_callout = tcp_timer_keep; 621 break; 622 case TT_2MSL: 623 t_callout = &tp->t_timers->tt_2msl; 624 f_callout = tcp_timer_2msl; 625 break; 626 default: 627 panic("bad timer_type"); 628 } 629 if (delta == 0) { 630 callout_stop(t_callout); 631 } else { 632 callout_reset_on(t_callout, delta, f_callout, tp, cpu); 633 } 634 } 635 636 int 637 tcp_timer_active(struct tcpcb *tp, int timer_type) 638 { 639 struct callout *t_callout; 640 641 switch (timer_type) { 642 case TT_DELACK: 643 t_callout = &tp->t_timers->tt_delack; 644 break; 645 case TT_REXMT: 646 t_callout = &tp->t_timers->tt_rexmt; 647 break; 648 case TT_PERSIST: 649 t_callout = &tp->t_timers->tt_persist; 650 break; 651 case TT_KEEP: 652 t_callout = &tp->t_timers->tt_keep; 653 break; 654 case TT_2MSL: 655 t_callout = &tp->t_timers->tt_2msl; 656 break; 657 default: 658 panic("bad timer_type"); 659 } 660 return callout_active(t_callout); 661 } 662 663 #define ticks_to_msecs(t) (1000*(t) / hz) 664 665 void 666 tcp_timer_to_xtimer(struct tcpcb *tp, struct tcp_timer *timer, struct xtcp_timer *xtimer) 667 { 668 bzero(xtimer, sizeof(struct xtcp_timer)); 669 if (timer == NULL) 670 return; 671 if (callout_active(&timer->tt_delack)) 672 xtimer->tt_delack = ticks_to_msecs(timer->tt_delack.c_time - ticks); 673 if (callout_active(&timer->tt_rexmt)) 674 xtimer->tt_rexmt = ticks_to_msecs(timer->tt_rexmt.c_time - ticks); 675 if (callout_active(&timer->tt_persist)) 676 xtimer->tt_persist = ticks_to_msecs(timer->tt_persist.c_time - ticks); 677 if (callout_active(&timer->tt_keep)) 678 xtimer->tt_keep = ticks_to_msecs(timer->tt_keep.c_time - ticks); 679 if (callout_active(&timer->tt_2msl)) 680 xtimer->tt_2msl = ticks_to_msecs(timer->tt_2msl.c_time - ticks); 681 xtimer->t_rcvtime = ticks_to_msecs(ticks - tp->t_rcvtime); 682 }
Cache object: 0be971146b2268efbeda7dc161f5271c
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