| 1 | /* $NetBSD: tcp_timer.c,v 1.91 2016/07/25 00:10:38 knakahara 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 1.91 2016/07/25 00:10:38 knakahara Exp $" ); |
| 97 | |
| 98 | #ifdef _KERNEL_OPT |
| 99 | #include "opt_inet.h" |
| 100 | #include "opt_tcp_debug.h" |
| 101 | #endif |
| 102 | |
| 103 | #include <sys/param.h> |
| 104 | #include <sys/systm.h> |
| 105 | #include <sys/mbuf.h> |
| 106 | #include <sys/socket.h> |
| 107 | #include <sys/socketvar.h> |
| 108 | #include <sys/protosw.h> |
| 109 | #include <sys/errno.h> |
| 110 | #include <sys/kernel.h> |
| 111 | |
| 112 | #include <net/if.h> |
| 113 | |
| 114 | #include <netinet/in.h> |
| 115 | #include <netinet/in_systm.h> |
| 116 | #include <netinet/ip.h> |
| 117 | #include <netinet/in_pcb.h> |
| 118 | #include <netinet/ip_var.h> |
| 119 | #include <netinet/ip_icmp.h> |
| 120 | |
| 121 | #ifdef INET6 |
| 122 | #ifndef INET |
| 123 | #include <netinet/in.h> |
| 124 | #endif |
| 125 | #include <netinet/ip6.h> |
| 126 | #include <netinet6/in6_pcb.h> |
| 127 | #endif |
| 128 | |
| 129 | #include <netinet/tcp.h> |
| 130 | #include <netinet/tcp_fsm.h> |
| 131 | #include <netinet/tcp_seq.h> |
| 132 | #include <netinet/tcp_timer.h> |
| 133 | #include <netinet/tcp_var.h> |
| 134 | #include <netinet/tcp_private.h> |
| 135 | #include <netinet/tcp_congctl.h> |
| 136 | #include <netinet/tcpip.h> |
| 137 | #ifdef TCP_DEBUG |
| 138 | #include <netinet/tcp_debug.h> |
| 139 | #endif |
| 140 | |
| 141 | /* |
| 142 | * Various tunable timer parameters. These are initialized in tcp_init(), |
| 143 | * unless they are patched. |
| 144 | */ |
| 145 | u_int tcp_keepinit = 0; |
| 146 | u_int tcp_keepidle = 0; |
| 147 | u_int tcp_keepintvl = 0; |
| 148 | u_int tcp_keepcnt = 0; /* max idle probes */ |
| 149 | |
| 150 | int tcp_maxpersistidle = 0; /* max idle time in persist */ |
| 151 | |
| 152 | /* |
| 153 | * Time to delay the ACK. This is initialized in tcp_init(), unless |
| 154 | * its patched. |
| 155 | */ |
| 156 | int tcp_delack_ticks = 0; |
| 157 | |
| 158 | void tcp_timer_rexmt(void *); |
| 159 | void tcp_timer_persist(void *); |
| 160 | void tcp_timer_keep(void *); |
| 161 | void tcp_timer_2msl(void *); |
| 162 | |
| 163 | const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS] = { |
| 164 | tcp_timer_rexmt, |
| 165 | tcp_timer_persist, |
| 166 | tcp_timer_keep, |
| 167 | tcp_timer_2msl, |
| 168 | }; |
| 169 | |
| 170 | /* |
| 171 | * Timer state initialization, called from tcp_init(). |
| 172 | */ |
| 173 | void |
| 174 | tcp_timer_init(void) |
| 175 | { |
| 176 | |
| 177 | if (tcp_keepinit == 0) |
| 178 | tcp_keepinit = TCPTV_KEEP_INIT; |
| 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 | * Callout to process delayed ACKs for a TCPCB. |
| 198 | */ |
| 199 | void |
| 200 | tcp_delack(void *arg) |
| 201 | { |
| 202 | struct tcpcb *tp = arg; |
| 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 | mutex_enter(softnet_lock); |
| 211 | if ((tp->t_flags & (TF_DEAD | TF_DELACK)) != TF_DELACK) { |
| 212 | mutex_exit(softnet_lock); |
| 213 | return; |
| 214 | } |
| 215 | if (!callout_expired(&tp->t_delack_ch)) { |
| 216 | mutex_exit(softnet_lock); |
| 217 | return; |
| 218 | } |
| 219 | |
| 220 | tp->t_flags |= TF_ACKNOW; |
| 221 | KERNEL_LOCK(1, NULL); |
| 222 | (void) tcp_output(tp); |
| 223 | KERNEL_UNLOCK_ONE(NULL); |
| 224 | mutex_exit(softnet_lock); |
| 225 | } |
| 226 | |
| 227 | /* |
| 228 | * Tcp protocol timeout routine called every 500 ms. |
| 229 | * Updates the timers in all active tcb's and |
| 230 | * causes finite state machine actions if timers expire. |
| 231 | */ |
| 232 | void |
| 233 | tcp_slowtimo(void *arg) |
| 234 | { |
| 235 | |
| 236 | mutex_enter(softnet_lock); |
| 237 | tcp_iss_seq += TCP_ISSINCR; /* increment iss */ |
| 238 | tcp_now++; /* for timestamps */ |
| 239 | mutex_exit(softnet_lock); |
| 240 | |
| 241 | callout_schedule(&tcp_slowtimo_ch, hz / PR_SLOWHZ); |
| 242 | } |
| 243 | |
| 244 | /* |
| 245 | * Cancel all timers for TCP tp. |
| 246 | */ |
| 247 | void |
| 248 | tcp_canceltimers(struct tcpcb *tp) |
| 249 | { |
| 250 | int i; |
| 251 | |
| 252 | for (i = 0; i < TCPT_NTIMERS; i++) |
| 253 | TCP_TIMER_DISARM(tp, i); |
| 254 | } |
| 255 | |
| 256 | const int tcp_backoff[TCP_MAXRXTSHIFT + 1] = |
| 257 | { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 }; |
| 258 | |
| 259 | const int tcp_totbackoff = 511; /* sum of tcp_backoff[] */ |
| 260 | |
| 261 | /* |
| 262 | * TCP timer processing. |
| 263 | */ |
| 264 | |
| 265 | void |
| 266 | tcp_timer_rexmt(void *arg) |
| 267 | { |
| 268 | struct tcpcb *tp = arg; |
| 269 | uint32_t rto; |
| 270 | #ifdef TCP_DEBUG |
| 271 | struct socket *so = NULL; |
| 272 | short ostate; |
| 273 | #endif |
| 274 | |
| 275 | mutex_enter(softnet_lock); |
| 276 | if ((tp->t_flags & TF_DEAD) != 0) { |
| 277 | mutex_exit(softnet_lock); |
| 278 | return; |
| 279 | } |
| 280 | if (!callout_expired(&tp->t_timer[TCPT_REXMT])) { |
| 281 | mutex_exit(softnet_lock); |
| 282 | return; |
| 283 | } |
| 284 | |
| 285 | KERNEL_LOCK(1, NULL); |
| 286 | if ((tp->t_flags & TF_PMTUD_PEND) && tp->t_inpcb && |
| 287 | SEQ_GEQ(tp->t_pmtud_th_seq, tp->snd_una) && |
| 288 | SEQ_LT(tp->t_pmtud_th_seq, (int)(tp->snd_una + tp->t_ourmss))) { |
| 289 | extern struct sockaddr_in icmpsrc; |
| 290 | struct icmp icmp; |
| 291 | |
| 292 | tp->t_flags &= ~TF_PMTUD_PEND; |
| 293 | |
| 294 | /* XXX create fake icmp message with relevant entries */ |
| 295 | icmp.icmp_nextmtu = tp->t_pmtud_nextmtu; |
| 296 | icmp.icmp_ip.ip_len = tp->t_pmtud_ip_len; |
| 297 | icmp.icmp_ip.ip_hl = tp->t_pmtud_ip_hl; |
| 298 | icmpsrc.sin_addr = tp->t_inpcb->inp_faddr; |
| 299 | icmp_mtudisc(&icmp, icmpsrc.sin_addr); |
| 300 | |
| 301 | /* |
| 302 | * Notify all connections to the same peer about |
| 303 | * new mss and trigger retransmit. |
| 304 | */ |
| 305 | in_pcbnotifyall(&tcbtable, icmpsrc.sin_addr, EMSGSIZE, |
| 306 | tcp_mtudisc); |
| 307 | KERNEL_UNLOCK_ONE(NULL); |
| 308 | mutex_exit(softnet_lock); |
| 309 | return; |
| 310 | } |
| 311 | #ifdef TCP_DEBUG |
| 312 | #ifdef INET |
| 313 | if (tp->t_inpcb) |
| 314 | so = tp->t_inpcb->inp_socket; |
| 315 | #endif |
| 316 | #ifdef INET6 |
| 317 | if (tp->t_in6pcb) |
| 318 | so = tp->t_in6pcb->in6p_socket; |
| 319 | #endif |
| 320 | ostate = tp->t_state; |
| 321 | #endif /* TCP_DEBUG */ |
| 322 | |
| 323 | /* |
| 324 | * Clear the SACK scoreboard, reset FACK estimate. |
| 325 | */ |
| 326 | tcp_free_sackholes(tp); |
| 327 | tp->snd_fack = tp->snd_una; |
| 328 | |
| 329 | /* |
| 330 | * Retransmission timer went off. Message has not |
| 331 | * been acked within retransmit interval. Back off |
| 332 | * to a longer retransmit interval and retransmit one segment. |
| 333 | */ |
| 334 | |
| 335 | if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { |
| 336 | tp->t_rxtshift = TCP_MAXRXTSHIFT; |
| 337 | TCP_STATINC(TCP_STAT_TIMEOUTDROP); |
| 338 | tp = tcp_drop(tp, tp->t_softerror ? |
| 339 | tp->t_softerror : ETIMEDOUT); |
| 340 | goto out; |
| 341 | } |
| 342 | TCP_STATINC(TCP_STAT_REXMTTIMEO); |
| 343 | rto = TCP_REXMTVAL(tp); |
| 344 | if (rto < tp->t_rttmin) |
| 345 | rto = tp->t_rttmin; |
| 346 | TCPT_RANGESET(tp->t_rxtcur, rto * tcp_backoff[tp->t_rxtshift], |
| 347 | tp->t_rttmin, TCPTV_REXMTMAX); |
| 348 | TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); |
| 349 | |
| 350 | /* |
| 351 | * If we are losing and we are trying path MTU discovery, |
| 352 | * try turning it off. This will avoid black holes in |
| 353 | * the network which suppress or fail to send "packet |
| 354 | * too big" ICMP messages. We should ideally do |
| 355 | * lots more sophisticated searching to find the right |
| 356 | * value here... |
| 357 | */ |
| 358 | if (tp->t_mtudisc && tp->t_rxtshift > TCP_MAXRXTSHIFT / 6) { |
| 359 | TCP_STATINC(TCP_STAT_PMTUBLACKHOLE); |
| 360 | |
| 361 | #ifdef INET |
| 362 | /* try turning PMTUD off */ |
| 363 | if (tp->t_inpcb) |
| 364 | tp->t_mtudisc = 0; |
| 365 | #endif |
| 366 | #ifdef INET6 |
| 367 | /* try using IPv6 minimum MTU */ |
| 368 | if (tp->t_in6pcb) |
| 369 | tp->t_mtudisc = 0; |
| 370 | #endif |
| 371 | |
| 372 | /* XXX: more sophisticated Black hole recovery code? */ |
| 373 | } |
| 374 | |
| 375 | /* |
| 376 | * If losing, let the lower level know and try for |
| 377 | * a better route. Also, if we backed off this far, |
| 378 | * our srtt estimate is probably bogus. Clobber it |
| 379 | * so we'll take the next rtt measurement as our srtt; |
| 380 | * move the current srtt into rttvar to keep the current |
| 381 | * retransmit times until then. |
| 382 | */ |
| 383 | if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { |
| 384 | #ifdef INET |
| 385 | if (tp->t_inpcb) |
| 386 | in_losing(tp->t_inpcb); |
| 387 | #endif |
| 388 | #ifdef INET6 |
| 389 | if (tp->t_in6pcb) |
| 390 | in6_losing(tp->t_in6pcb); |
| 391 | #endif |
| 392 | /* |
| 393 | * This operation is not described in RFC2988. The |
| 394 | * point is to keep srtt+4*rttvar constant, so we |
| 395 | * should shift right 2 bits to divide by 4, and then |
| 396 | * shift right one bit because the storage |
| 397 | * representation of rttvar is 1/16s vs 1/32s for |
| 398 | * srtt. |
| 399 | */ |
| 400 | tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); |
| 401 | tp->t_srtt = 0; |
| 402 | } |
| 403 | tp->snd_nxt = tp->snd_una; |
| 404 | tp->snd_high = tp->snd_max; |
| 405 | /* |
| 406 | * If timing a segment in this window, stop the timer. |
| 407 | */ |
| 408 | tp->t_rtttime = 0; |
| 409 | /* |
| 410 | * Remember if we are retransmitting a SYN, because if |
| 411 | * we do, set the initial congestion window must be set |
| 412 | * to 1 segment. |
| 413 | */ |
| 414 | if (tp->t_state == TCPS_SYN_SENT) |
| 415 | tp->t_flags |= TF_SYN_REXMT; |
| 416 | |
| 417 | /* |
| 418 | * Adjust congestion control parameters. |
| 419 | */ |
| 420 | tp->t_congctl->slow_retransmit(tp); |
| 421 | |
| 422 | (void) tcp_output(tp); |
| 423 | |
| 424 | out: |
| 425 | #ifdef TCP_DEBUG |
| 426 | if (tp && so->so_options & SO_DEBUG) |
| 427 | tcp_trace(TA_USER, ostate, tp, NULL, |
| 428 | PRU_SLOWTIMO | (TCPT_REXMT << 8)); |
| 429 | #endif |
| 430 | KERNEL_UNLOCK_ONE(NULL); |
| 431 | mutex_exit(softnet_lock); |
| 432 | } |
| 433 | |
| 434 | void |
| 435 | tcp_timer_persist(void *arg) |
| 436 | { |
| 437 | struct tcpcb *tp = arg; |
| 438 | uint32_t rto; |
| 439 | #ifdef TCP_DEBUG |
| 440 | struct socket *so = NULL; |
| 441 | short ostate; |
| 442 | #endif |
| 443 | |
| 444 | mutex_enter(softnet_lock); |
| 445 | if ((tp->t_flags & TF_DEAD) != 0) { |
| 446 | mutex_exit(softnet_lock); |
| 447 | return; |
| 448 | } |
| 449 | if (!callout_expired(&tp->t_timer[TCPT_PERSIST])) { |
| 450 | mutex_exit(softnet_lock); |
| 451 | return; |
| 452 | } |
| 453 | |
| 454 | KERNEL_LOCK(1, NULL); |
| 455 | #ifdef TCP_DEBUG |
| 456 | #ifdef INET |
| 457 | if (tp->t_inpcb) |
| 458 | so = tp->t_inpcb->inp_socket; |
| 459 | #endif |
| 460 | #ifdef INET6 |
| 461 | if (tp->t_in6pcb) |
| 462 | so = tp->t_in6pcb->in6p_socket; |
| 463 | #endif |
| 464 | |
| 465 | ostate = tp->t_state; |
| 466 | #endif /* TCP_DEBUG */ |
| 467 | |
| 468 | /* |
| 469 | * Persistance timer into zero window. |
| 470 | * Force a byte to be output, if possible. |
| 471 | */ |
| 472 | |
| 473 | /* |
| 474 | * Hack: if the peer is dead/unreachable, we do not |
| 475 | * time out if the window is closed. After a full |
| 476 | * backoff, drop the connection if the idle time |
| 477 | * (no responses to probes) reaches the maximum |
| 478 | * backoff that we would use if retransmitting. |
| 479 | */ |
| 480 | rto = TCP_REXMTVAL(tp); |
| 481 | if (rto < tp->t_rttmin) |
| 482 | rto = tp->t_rttmin; |
| 483 | if (tp->t_rxtshift == TCP_MAXRXTSHIFT && |
| 484 | ((tcp_now - tp->t_rcvtime) >= tcp_maxpersistidle || |
| 485 | (tcp_now - tp->t_rcvtime) >= rto * tcp_totbackoff)) { |
| 486 | TCP_STATINC(TCP_STAT_PERSISTDROPS); |
| 487 | tp = tcp_drop(tp, ETIMEDOUT); |
| 488 | goto out; |
| 489 | } |
| 490 | TCP_STATINC(TCP_STAT_PERSISTTIMEO); |
| 491 | tcp_setpersist(tp); |
| 492 | tp->t_force = 1; |
| 493 | (void) tcp_output(tp); |
| 494 | tp->t_force = 0; |
| 495 | |
| 496 | out: |
| 497 | #ifdef TCP_DEBUG |
| 498 | if (tp && so->so_options & SO_DEBUG) |
| 499 | tcp_trace(TA_USER, ostate, tp, NULL, |
| 500 | PRU_SLOWTIMO | (TCPT_PERSIST << 8)); |
| 501 | #endif |
| 502 | KERNEL_UNLOCK_ONE(NULL); |
| 503 | mutex_exit(softnet_lock); |
| 504 | } |
| 505 | |
| 506 | void |
| 507 | tcp_timer_keep(void *arg) |
| 508 | { |
| 509 | struct tcpcb *tp = arg; |
| 510 | struct socket *so = NULL; /* Quell compiler warning */ |
| 511 | #ifdef TCP_DEBUG |
| 512 | short ostate; |
| 513 | #endif |
| 514 | |
| 515 | mutex_enter(softnet_lock); |
| 516 | if ((tp->t_flags & TF_DEAD) != 0) { |
| 517 | mutex_exit(softnet_lock); |
| 518 | return; |
| 519 | } |
| 520 | if (!callout_expired(&tp->t_timer[TCPT_KEEP])) { |
| 521 | mutex_exit(softnet_lock); |
| 522 | return; |
| 523 | } |
| 524 | |
| 525 | KERNEL_LOCK(1, NULL); |
| 526 | |
| 527 | #ifdef TCP_DEBUG |
| 528 | ostate = tp->t_state; |
| 529 | #endif /* TCP_DEBUG */ |
| 530 | |
| 531 | /* |
| 532 | * Keep-alive timer went off; send something |
| 533 | * or drop connection if idle for too long. |
| 534 | */ |
| 535 | |
| 536 | TCP_STATINC(TCP_STAT_KEEPTIMEO); |
| 537 | if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) |
| 538 | goto dropit; |
| 539 | #ifdef INET |
| 540 | if (tp->t_inpcb) |
| 541 | so = tp->t_inpcb->inp_socket; |
| 542 | #endif |
| 543 | #ifdef INET6 |
| 544 | if (tp->t_in6pcb) |
| 545 | so = tp->t_in6pcb->in6p_socket; |
| 546 | #endif |
| 547 | KASSERT(so != NULL); |
| 548 | if (so->so_options & SO_KEEPALIVE && |
| 549 | tp->t_state <= TCPS_CLOSE_WAIT) { |
| 550 | if ((tp->t_maxidle > 0) && |
| 551 | ((tcp_now - tp->t_rcvtime) >= |
| 552 | tp->t_keepidle + tp->t_maxidle)) |
| 553 | goto dropit; |
| 554 | /* |
| 555 | * Send a packet designed to force a response |
| 556 | * if the peer is up and reachable: |
| 557 | * either an ACK if the connection is still alive, |
| 558 | * or an RST if the peer has closed the connection |
| 559 | * due to timeout or reboot. |
| 560 | * Using sequence number tp->snd_una-1 |
| 561 | * causes the transmitted zero-length segment |
| 562 | * to lie outside the receive window; |
| 563 | * by the protocol spec, this requires the |
| 564 | * correspondent TCP to respond. |
| 565 | */ |
| 566 | TCP_STATINC(TCP_STAT_KEEPPROBE); |
| 567 | if (tcp_compat_42) { |
| 568 | /* |
| 569 | * The keepalive packet must have nonzero |
| 570 | * length to get a 4.2 host to respond. |
| 571 | */ |
| 572 | (void)tcp_respond(tp, tp->t_template, |
| 573 | NULL, NULL, tp->rcv_nxt - 1, |
| 574 | tp->snd_una - 1, 0); |
| 575 | } else { |
| 576 | (void)tcp_respond(tp, tp->t_template, |
| 577 | NULL, NULL, tp->rcv_nxt, |
| 578 | tp->snd_una - 1, 0); |
| 579 | } |
| 580 | TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepintvl); |
| 581 | } else |
| 582 | TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepidle); |
| 583 | |
| 584 | #ifdef TCP_DEBUG |
| 585 | if (tp && so->so_options & SO_DEBUG) |
| 586 | tcp_trace(TA_USER, ostate, tp, NULL, |
| 587 | PRU_SLOWTIMO | (TCPT_KEEP << 8)); |
| 588 | #endif |
| 589 | KERNEL_UNLOCK_ONE(NULL); |
| 590 | mutex_exit(softnet_lock); |
| 591 | return; |
| 592 | |
| 593 | dropit: |
| 594 | TCP_STATINC(TCP_STAT_KEEPDROPS); |
| 595 | (void) tcp_drop(tp, ETIMEDOUT); |
| 596 | KERNEL_UNLOCK_ONE(NULL); |
| 597 | mutex_exit(softnet_lock); |
| 598 | } |
| 599 | |
| 600 | void |
| 601 | tcp_timer_2msl(void *arg) |
| 602 | { |
| 603 | struct tcpcb *tp = arg; |
| 604 | #ifdef TCP_DEBUG |
| 605 | struct socket *so = NULL; |
| 606 | short ostate; |
| 607 | #endif |
| 608 | |
| 609 | mutex_enter(softnet_lock); |
| 610 | if ((tp->t_flags & TF_DEAD) != 0) { |
| 611 | mutex_exit(softnet_lock); |
| 612 | return; |
| 613 | } |
| 614 | if (!callout_expired(&tp->t_timer[TCPT_2MSL])) { |
| 615 | mutex_exit(softnet_lock); |
| 616 | return; |
| 617 | } |
| 618 | |
| 619 | /* |
| 620 | * 2 MSL timeout went off, clear the SACK scoreboard, reset |
| 621 | * the FACK estimate. |
| 622 | */ |
| 623 | KERNEL_LOCK(1, NULL); |
| 624 | tcp_free_sackholes(tp); |
| 625 | tp->snd_fack = tp->snd_una; |
| 626 | |
| 627 | #ifdef TCP_DEBUG |
| 628 | #ifdef INET |
| 629 | if (tp->t_inpcb) |
| 630 | so = tp->t_inpcb->inp_socket; |
| 631 | #endif |
| 632 | #ifdef INET6 |
| 633 | if (tp->t_in6pcb) |
| 634 | so = tp->t_in6pcb->in6p_socket; |
| 635 | #endif |
| 636 | |
| 637 | ostate = tp->t_state; |
| 638 | #endif /* TCP_DEBUG */ |
| 639 | |
| 640 | /* |
| 641 | * 2 MSL timeout in shutdown went off. If we're closed but |
| 642 | * still waiting for peer to close and connection has been idle |
| 643 | * too long, or if 2MSL time is up from TIME_WAIT, delete connection |
| 644 | * control block. Otherwise, check again in a bit. |
| 645 | */ |
| 646 | if (tp->t_state != TCPS_TIME_WAIT && |
| 647 | ((tp->t_maxidle == 0) || |
| 648 | ((tcp_now - tp->t_rcvtime) <= tp->t_maxidle))) |
| 649 | TCP_TIMER_ARM(tp, TCPT_2MSL, tp->t_keepintvl); |
| 650 | else |
| 651 | tp = tcp_close(tp); |
| 652 | |
| 653 | #ifdef TCP_DEBUG |
| 654 | if (tp && so->so_options & SO_DEBUG) |
| 655 | tcp_trace(TA_USER, ostate, tp, NULL, |
| 656 | PRU_SLOWTIMO | (TCPT_2MSL << 8)); |
| 657 | #endif |
| 658 | KERNEL_UNLOCK_ONE(NULL); |
| 659 | mutex_exit(softnet_lock); |
| 660 | } |
| 661 | |