| File: | netinet/tcp_timer.c |
| Warning: | line 499, column 2 Value stored to 'tp' is never read |
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| 1 | /* $OpenBSD: tcp_timer.c,v 1.73 2023/07/06 09:15:24 bluhm Exp $ */ |
| 2 | /* $NetBSD: tcp_timer.c,v 1.14 1996/02/13 23:44:09 christos Exp $ */ |
| 3 | |
| 4 | /* |
| 5 | * Copyright (c) 1982, 1986, 1988, 1990, 1993 |
| 6 | * The Regents of the University of California. All rights reserved. |
| 7 | * |
| 8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions |
| 10 | * are met: |
| 11 | * 1. Redistributions of source code must retain the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer. |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer in the |
| 15 | * documentation and/or other materials provided with the distribution. |
| 16 | * 3. Neither the name of the University nor the names of its contributors |
| 17 | * may be used to endorse or promote products derived from this software |
| 18 | * without specific prior written permission. |
| 19 | * |
| 20 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 21 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 22 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 23 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 24 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 25 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 26 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 27 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 28 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 29 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 30 | * SUCH DAMAGE. |
| 31 | * |
| 32 | * @(#)tcp_timer.c 8.1 (Berkeley) 6/10/93 |
| 33 | */ |
| 34 | |
| 35 | #include <sys/param.h> |
| 36 | #include <sys/systm.h> |
| 37 | #include <sys/mbuf.h> |
| 38 | #include <sys/socket.h> |
| 39 | #include <sys/socketvar.h> |
| 40 | #include <sys/protosw.h> |
| 41 | #include <sys/kernel.h> |
| 42 | #include <sys/pool.h> |
| 43 | |
| 44 | #include <net/route.h> |
| 45 | |
| 46 | #include <netinet/in.h> |
| 47 | #include <netinet/ip.h> |
| 48 | #include <netinet/in_pcb.h> |
| 49 | #include <netinet/ip_var.h> |
| 50 | #include <netinet/tcp.h> |
| 51 | #include <netinet/tcp_fsm.h> |
| 52 | #include <netinet/tcp_timer.h> |
| 53 | #include <netinet/tcp_var.h> |
| 54 | #include <netinet/tcp_debug.h> |
| 55 | #include <netinet/ip_icmp.h> |
| 56 | #include <netinet/tcp_seq.h> |
| 57 | |
| 58 | /* |
| 59 | * Locks used to protect struct members in this file: |
| 60 | * T tcp_timer_mtx global tcp timer data structures |
| 61 | */ |
| 62 | |
| 63 | int tcp_always_keepalive; |
| 64 | int tcp_keepidle; |
| 65 | int tcp_keepintvl; |
| 66 | int tcp_maxpersistidle; /* max idle time in persist */ |
| 67 | int tcp_maxidle; /* [T] max idle time for keep alive */ |
| 68 | |
| 69 | /* |
| 70 | * Time to delay the ACK. This is initialized in tcp_init(), unless |
| 71 | * its patched. |
| 72 | */ |
| 73 | int tcp_delack_msecs; |
| 74 | |
| 75 | void tcp_timer_rexmt(void *); |
| 76 | void tcp_timer_persist(void *); |
| 77 | void tcp_timer_keep(void *); |
| 78 | void tcp_timer_2msl(void *); |
| 79 | void tcp_timer_reaper(void *); |
| 80 | void tcp_timer_delack(void *); |
| 81 | |
| 82 | const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS6] = { |
| 83 | tcp_timer_rexmt, |
| 84 | tcp_timer_persist, |
| 85 | tcp_timer_keep, |
| 86 | tcp_timer_2msl, |
| 87 | tcp_timer_reaper, |
| 88 | tcp_timer_delack, |
| 89 | }; |
| 90 | |
| 91 | /* |
| 92 | * Timer state initialization, called from tcp_init(). |
| 93 | */ |
| 94 | void |
| 95 | tcp_timer_init(void) |
| 96 | { |
| 97 | |
| 98 | if (tcp_keepidle == 0) |
| 99 | tcp_keepidle = TCPTV_KEEP_IDLE((120*60) * 1000); |
| 100 | |
| 101 | if (tcp_keepintvl == 0) |
| 102 | tcp_keepintvl = TCPTV_KEEPINTVL((75) * 1000); |
| 103 | |
| 104 | if (tcp_maxpersistidle == 0) |
| 105 | tcp_maxpersistidle = TCPTV_KEEP_IDLE((120*60) * 1000); |
| 106 | |
| 107 | if (tcp_delack_msecs == 0) |
| 108 | tcp_delack_msecs = TCP_DELACK_MSECS200; |
| 109 | } |
| 110 | |
| 111 | /* |
| 112 | * Callout to process delayed ACKs for a TCPCB. |
| 113 | */ |
| 114 | void |
| 115 | tcp_timer_delack(void *arg) |
| 116 | { |
| 117 | struct tcpcb *otp = NULL((void *)0), *tp = arg; |
| 118 | short ostate; |
| 119 | |
| 120 | /* |
| 121 | * If tcp_output() wasn't able to transmit the ACK |
| 122 | * for whatever reason, it will restart the delayed |
| 123 | * ACK callout. |
| 124 | */ |
| 125 | NET_LOCK()do { rw_enter_write(&netlock); } while (0); |
| 126 | /* Ignore canceled timeouts or timeouts that have been rescheduled. */ |
| 127 | if (!ISSET((tp)->t_flags, TF_TMR_DELACK)(((tp)->t_flags) & (0x80000000U)) || |
| 128 | timeout_pending(&tp->t_timer[TCPT_DELACK])((&tp->t_timer[5])->to_flags & 0x02)) |
| 129 | goto out; |
| 130 | CLR((tp)->t_flags, TF_TMR_DELACK)(((tp)->t_flags) &= ~(0x80000000U)); |
| 131 | |
| 132 | if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG0x0001) { |
| 133 | otp = tp; |
| 134 | ostate = tp->t_state; |
| 135 | } |
| 136 | tp->t_flags |= TF_ACKNOW0x0001U; |
| 137 | (void) tcp_output(tp); |
| 138 | if (otp) |
| 139 | tcp_trace(TA_TIMER5, ostate, tp, otp, NULL((void *)0), TCPT_DELACK5, 0); |
| 140 | out: |
| 141 | NET_UNLOCK()do { rw_exit_write(&netlock); } while (0); |
| 142 | } |
| 143 | |
| 144 | /* |
| 145 | * Tcp protocol timeout routine called every 500 ms. |
| 146 | * Updates the timers in all active tcb's and |
| 147 | * causes finite state machine actions if timers expire. |
| 148 | */ |
| 149 | void |
| 150 | tcp_slowtimo(void) |
| 151 | { |
| 152 | mtx_enter(&tcp_timer_mtx); |
| 153 | tcp_maxidle = TCPTV_KEEPCNT8 * tcp_keepintvl; |
| 154 | tcp_iss += TCP_ISSINCR2(1*1024*1024)/PR_SLOWHZ2; /* increment iss */ |
| 155 | mtx_leave(&tcp_timer_mtx); |
| 156 | } |
| 157 | |
| 158 | /* |
| 159 | * Cancel all timers for TCP tp. |
| 160 | */ |
| 161 | void |
| 162 | tcp_canceltimers(struct tcpcb *tp) |
| 163 | { |
| 164 | int i; |
| 165 | |
| 166 | for (i = 0; i < TCPT_NTIMERS6; i++) |
| 167 | TCP_TIMER_DISARM(tp, i)do { (((tp)->t_flags) &= ~(0x04000000U << (i))); timeout_del(&(tp)->t_timer[(i)]); } while (0); |
| 168 | } |
| 169 | |
| 170 | int tcp_backoff[TCP_MAXRXTSHIFT12 + 1] = |
| 171 | { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 }; |
| 172 | |
| 173 | int tcp_totbackoff = 511; /* sum of tcp_backoff[] */ |
| 174 | |
| 175 | /* |
| 176 | * TCP timer processing. |
| 177 | */ |
| 178 | |
| 179 | void tcp_timer_freesack(struct tcpcb *); |
| 180 | |
| 181 | void |
| 182 | tcp_timer_freesack(struct tcpcb *tp) |
| 183 | { |
| 184 | struct sackhole *p, *q; |
| 185 | /* |
| 186 | * Free SACK holes for 2MSL and REXMT timers. |
| 187 | */ |
| 188 | q = tp->snd_holes; |
| 189 | while (q != NULL((void *)0)) { |
| 190 | p = q; |
| 191 | q = q->next; |
| 192 | pool_put(&sackhl_pool, p); |
| 193 | } |
| 194 | tp->snd_holes = 0; |
| 195 | } |
| 196 | |
| 197 | void |
| 198 | tcp_timer_rexmt(void *arg) |
| 199 | { |
| 200 | struct tcpcb *otp = NULL((void *)0), *tp = arg; |
| 201 | uint32_t rto; |
| 202 | short ostate; |
| 203 | |
| 204 | NET_LOCK()do { rw_enter_write(&netlock); } while (0); |
| 205 | /* Ignore canceled timeouts or timeouts that have been rescheduled. */ |
| 206 | if (!ISSET((tp)->t_flags, TF_TMR_REXMT)(((tp)->t_flags) & (0x04000000U)) || |
| 207 | timeout_pending(&tp->t_timer[TCPT_REXMT])((&tp->t_timer[0])->to_flags & 0x02)) |
| 208 | goto out; |
| 209 | CLR((tp)->t_flags, TF_TMR_REXMT)(((tp)->t_flags) &= ~(0x04000000U)); |
| 210 | |
| 211 | if ((tp->t_flags & TF_PMTUD_PEND0x00400000U) && tp->t_inpcb && |
| 212 | SEQ_GEQ(tp->t_pmtud_th_seq, tp->snd_una)((int)((tp->t_pmtud_th_seq)-(tp->snd_una)) >= 0) && |
| 213 | SEQ_LT(tp->t_pmtud_th_seq, (int)(tp->snd_una + tp->t_maxseg))((int)((tp->t_pmtud_th_seq)-((int)(tp->snd_una + tp-> t_maxseg))) < 0)) { |
| 214 | struct sockaddr_in sin; |
| 215 | struct icmp icmp; |
| 216 | |
| 217 | tp->t_flags &= ~TF_PMTUD_PEND0x00400000U; |
| 218 | |
| 219 | /* XXX create fake icmp message with relevant entries */ |
| 220 | icmp.icmp_nextmtuicmp_hun.ih_pmtu.ipm_nextmtu = tp->t_pmtud_nextmtu; |
| 221 | icmp.icmp_ipicmp_dun.id_ip.idi_ip.ip_len = tp->t_pmtud_ip_len; |
| 222 | icmp.icmp_ipicmp_dun.id_ip.idi_ip.ip_hl = tp->t_pmtud_ip_hl; |
| 223 | icmp.icmp_ipicmp_dun.id_ip.idi_ip.ip_dst = tp->t_inpcb->inp_faddrinp_faddru.iau_a4u.inaddr; |
| 224 | icmp_mtudisc(&icmp, tp->t_inpcb->inp_rtableid); |
| 225 | |
| 226 | /* |
| 227 | * Notify all connections to the same peer about |
| 228 | * new mss and trigger retransmit. |
| 229 | */ |
| 230 | bzero(&sin, sizeof(sin))__builtin_bzero((&sin), (sizeof(sin))); |
| 231 | sin.sin_len = sizeof(sin); |
| 232 | sin.sin_family = AF_INET2; |
| 233 | sin.sin_addr = tp->t_inpcb->inp_faddrinp_faddru.iau_a4u.inaddr; |
| 234 | in_pcbnotifyall(&tcbtable, sintosa(&sin), |
| 235 | tp->t_inpcb->inp_rtableid, EMSGSIZE40, tcp_mtudisc); |
| 236 | goto out; |
| 237 | } |
| 238 | |
| 239 | tcp_timer_freesack(tp); |
| 240 | if (++tp->t_rxtshift > TCP_MAXRXTSHIFT12) { |
| 241 | tp->t_rxtshift = TCP_MAXRXTSHIFT12; |
| 242 | tcpstat_inc(tcps_timeoutdrop); |
| 243 | tp = tcp_drop(tp, tp->t_softerror ? |
| 244 | tp->t_softerror : ETIMEDOUT60); |
| 245 | goto out; |
| 246 | } |
| 247 | if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG0x0001) { |
| 248 | otp = tp; |
| 249 | ostate = tp->t_state; |
| 250 | } |
| 251 | tcpstat_inc(tcps_rexmttimeo); |
| 252 | rto = TCP_REXMTVAL(tp)((((tp)->t_srtt >> 3) + (tp)->t_rttvar) >> 2 ); |
| 253 | if (rto < tp->t_rttmin) |
| 254 | rto = tp->t_rttmin; |
| 255 | TCPT_RANGESET(tp->t_rxtcur,do { (tp->t_rxtcur) = (rto * tcp_backoff[tp->t_rxtshift ]); if ((tp->t_rxtcur) < (tp->t_rttmin)) (tp->t_rxtcur ) = (tp->t_rttmin); else if ((tp->t_rxtcur) > (((64) * 1000))) (tp->t_rxtcur) = (((64) * 1000)); } while ( 0) |
| 256 | rto * tcp_backoff[tp->t_rxtshift],do { (tp->t_rxtcur) = (rto * tcp_backoff[tp->t_rxtshift ]); if ((tp->t_rxtcur) < (tp->t_rttmin)) (tp->t_rxtcur ) = (tp->t_rttmin); else if ((tp->t_rxtcur) > (((64) * 1000))) (tp->t_rxtcur) = (((64) * 1000)); } while ( 0) |
| 257 | tp->t_rttmin, TCPTV_REXMTMAX)do { (tp->t_rxtcur) = (rto * tcp_backoff[tp->t_rxtshift ]); if ((tp->t_rxtcur) < (tp->t_rttmin)) (tp->t_rxtcur ) = (tp->t_rttmin); else if ((tp->t_rxtcur) > (((64) * 1000))) (tp->t_rxtcur) = (((64) * 1000)); } while ( 0); |
| 258 | TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur)do { (((tp)->t_flags) |= (0x04000000U << (0))); timeout_add_msec (&(tp)->t_timer[(0)], (tp->t_rxtcur)); } while (0); |
| 259 | |
| 260 | /* |
| 261 | * If we are losing and we are trying path MTU discovery, |
| 262 | * try turning it off. This will avoid black holes in |
| 263 | * the network which suppress or fail to send "packet |
| 264 | * too big" ICMP messages. We should ideally do |
| 265 | * lots more sophisticated searching to find the right |
| 266 | * value here... |
| 267 | */ |
| 268 | if (ip_mtudisc && tp->t_inpcb && |
| 269 | TCPS_HAVEESTABLISHED(tp->t_state)((tp->t_state) >= 4) && |
| 270 | tp->t_rxtshift > TCP_MAXRXTSHIFT12 / 6) { |
| 271 | struct inpcb *inp = tp->t_inpcb; |
| 272 | struct rtentry *rt = NULL((void *)0); |
| 273 | |
| 274 | /* No data to send means path mtu is not a problem */ |
| 275 | if (!inp->inp_socket->so_snd.sb_cc) |
| 276 | goto leave; |
| 277 | |
| 278 | rt = in_pcbrtentry(inp); |
| 279 | /* Check if path MTU discovery is disabled already */ |
| 280 | if (rt && (rt->rt_flags & RTF_HOST0x4) && |
| 281 | (rt->rt_locksrt_rmx.rmx_locks & RTV_MTU0x1)) |
| 282 | goto leave; |
| 283 | |
| 284 | rt = NULL((void *)0); |
| 285 | switch(tp->pf) { |
| 286 | #ifdef INET61 |
| 287 | case PF_INET624: |
| 288 | /* |
| 289 | * We can not turn off path MTU for IPv6. |
| 290 | * Do nothing for now, maybe lower to |
| 291 | * minimum MTU. |
| 292 | */ |
| 293 | break; |
| 294 | #endif |
| 295 | case PF_INET2: |
| 296 | rt = icmp_mtudisc_clone(inp->inp_faddrinp_faddru.iau_a4u.inaddr, |
| 297 | inp->inp_rtableid, 0); |
| 298 | break; |
| 299 | } |
| 300 | if (rt != NULL((void *)0)) { |
| 301 | /* Disable path MTU discovery */ |
| 302 | if ((rt->rt_locksrt_rmx.rmx_locks & RTV_MTU0x1) == 0) { |
| 303 | rt->rt_locksrt_rmx.rmx_locks |= RTV_MTU0x1; |
| 304 | in_rtchange(inp, 0); |
| 305 | } |
| 306 | |
| 307 | rtfree(rt); |
| 308 | } |
| 309 | leave: |
| 310 | ; |
| 311 | } |
| 312 | |
| 313 | /* |
| 314 | * If losing, let the lower level know and try for |
| 315 | * a better route. Also, if we backed off this far, |
| 316 | * our srtt estimate is probably bogus. Clobber it |
| 317 | * so we'll take the next rtt measurement as our srtt; |
| 318 | * move the current srtt into rttvar to keep the current |
| 319 | * retransmit times until then. |
| 320 | */ |
| 321 | if (tp->t_rxtshift > TCP_MAXRXTSHIFT12 / 4) { |
| 322 | in_losing(tp->t_inpcb); |
| 323 | tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT3); |
| 324 | tp->t_srtt = 0; |
| 325 | } |
| 326 | tp->snd_nxt = tp->snd_una; |
| 327 | /* |
| 328 | * Note: We overload snd_last to function also as the |
| 329 | * snd_last variable described in RFC 2582 |
| 330 | */ |
| 331 | tp->snd_last = tp->snd_max; |
| 332 | /* |
| 333 | * If timing a segment in this window, stop the timer. |
| 334 | */ |
| 335 | tp->t_rtttime = 0; |
| 336 | #ifdef TCP_ECN1 |
| 337 | /* |
| 338 | * if ECN is enabled, there might be a broken firewall which |
| 339 | * blocks ecn packets. fall back to non-ecn. |
| 340 | */ |
| 341 | if ((tp->t_state == TCPS_SYN_SENT2 || tp->t_state == TCPS_SYN_RECEIVED3) |
| 342 | && tcp_do_ecn && !(tp->t_flags & TF_DISABLE_ECN0x00040000U)) |
| 343 | tp->t_flags |= TF_DISABLE_ECN0x00040000U; |
| 344 | #endif |
| 345 | /* |
| 346 | * Close the congestion window down to one segment |
| 347 | * (we'll open it by one segment for each ack we get). |
| 348 | * Since we probably have a window's worth of unacked |
| 349 | * data accumulated, this "slow start" keeps us from |
| 350 | * dumping all that data as back-to-back packets (which |
| 351 | * might overwhelm an intermediate gateway). |
| 352 | * |
| 353 | * There are two phases to the opening: Initially we |
| 354 | * open by one mss on each ack. This makes the window |
| 355 | * size increase exponentially with time. If the |
| 356 | * window is larger than the path can handle, this |
| 357 | * exponential growth results in dropped packet(s) |
| 358 | * almost immediately. To get more time between |
| 359 | * drops but still "push" the network to take advantage |
| 360 | * of improving conditions, we switch from exponential |
| 361 | * to linear window opening at some threshold size. |
| 362 | * For a threshold, we use half the current window |
| 363 | * size, truncated to a multiple of the mss. |
| 364 | * |
| 365 | * (the minimum cwnd that will give us exponential |
| 366 | * growth is 2 mss. We don't allow the threshold |
| 367 | * to go below this.) |
| 368 | */ |
| 369 | { |
| 370 | u_long win = ulmin(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_maxseg; |
| 371 | if (win < 2) |
| 372 | win = 2; |
| 373 | tp->snd_cwnd = tp->t_maxseg; |
| 374 | tp->snd_ssthresh = win * tp->t_maxseg; |
| 375 | tp->t_dupacks = 0; |
| 376 | #ifdef TCP_ECN1 |
| 377 | tp->snd_last = tp->snd_max; |
| 378 | tp->t_flags |= TF_SEND_CWR0x00020000U; |
| 379 | #endif |
| 380 | #if 1 /* TCP_ECN */ |
| 381 | tcpstat_inc(tcps_cwr_timeout); |
| 382 | #endif |
| 383 | } |
| 384 | (void) tcp_output(tp); |
| 385 | if (otp) |
| 386 | tcp_trace(TA_TIMER5, ostate, tp, otp, NULL((void *)0), TCPT_REXMT0, 0); |
| 387 | out: |
| 388 | NET_UNLOCK()do { rw_exit_write(&netlock); } while (0); |
| 389 | } |
| 390 | |
| 391 | void |
| 392 | tcp_timer_persist(void *arg) |
| 393 | { |
| 394 | struct tcpcb *otp = NULL((void *)0), *tp = arg; |
| 395 | uint32_t rto; |
| 396 | short ostate; |
| 397 | uint64_t now; |
| 398 | |
| 399 | NET_LOCK()do { rw_enter_write(&netlock); } while (0); |
| 400 | /* Ignore canceled timeouts or timeouts that have been rescheduled. */ |
| 401 | if (!ISSET((tp)->t_flags, TF_TMR_PERSIST)(((tp)->t_flags) & (0x08000000U)) || |
| 402 | timeout_pending(&tp->t_timer[TCPT_PERSIST])((&tp->t_timer[1])->to_flags & 0x02)) |
| 403 | goto out; |
| 404 | CLR((tp)->t_flags, TF_TMR_PERSIST)(((tp)->t_flags) &= ~(0x08000000U)); |
| 405 | |
| 406 | if (TCP_TIMER_ISARMED(tp, TCPT_REXMT)(((tp)->t_flags) & (0x04000000U << (0)))) |
| 407 | goto out; |
| 408 | |
| 409 | if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG0x0001) { |
| 410 | otp = tp; |
| 411 | ostate = tp->t_state; |
| 412 | } |
| 413 | tcpstat_inc(tcps_persisttimeo); |
| 414 | /* |
| 415 | * Hack: if the peer is dead/unreachable, we do not |
| 416 | * time out if the window is closed. After a full |
| 417 | * backoff, drop the connection if the idle time |
| 418 | * (no responses to probes) reaches the maximum |
| 419 | * backoff that we would use if retransmitting. |
| 420 | */ |
| 421 | rto = TCP_REXMTVAL(tp)((((tp)->t_srtt >> 3) + (tp)->t_rttvar) >> 2 ); |
| 422 | if (rto < tp->t_rttmin) |
| 423 | rto = tp->t_rttmin; |
| 424 | now = tcp_now(); |
| 425 | if (tp->t_rxtshift == TCP_MAXRXTSHIFT12 && |
| 426 | ((now - tp->t_rcvtime) >= tcp_maxpersistidle || |
| 427 | (now - tp->t_rcvtime) >= rto * tcp_totbackoff)) { |
| 428 | tcpstat_inc(tcps_persistdrop); |
| 429 | tp = tcp_drop(tp, ETIMEDOUT60); |
| 430 | goto out; |
| 431 | } |
| 432 | tcp_setpersist(tp); |
| 433 | tp->t_force = 1; |
| 434 | (void) tcp_output(tp); |
| 435 | tp->t_force = 0; |
| 436 | if (otp) |
| 437 | tcp_trace(TA_TIMER5, ostate, tp, otp, NULL((void *)0), TCPT_PERSIST1, 0); |
| 438 | out: |
| 439 | NET_UNLOCK()do { rw_exit_write(&netlock); } while (0); |
| 440 | } |
| 441 | |
| 442 | void |
| 443 | tcp_timer_keep(void *arg) |
| 444 | { |
| 445 | struct tcpcb *otp = NULL((void *)0), *tp = arg; |
| 446 | short ostate; |
| 447 | |
| 448 | NET_LOCK()do { rw_enter_write(&netlock); } while (0); |
| 449 | /* Ignore canceled timeouts or timeouts that have been rescheduled. */ |
| 450 | if (!ISSET((tp)->t_flags, TF_TMR_KEEP)(((tp)->t_flags) & (0x10000000U)) || |
| 451 | timeout_pending(&tp->t_timer[TCPT_KEEP])((&tp->t_timer[2])->to_flags & 0x02)) |
| 452 | goto out; |
| 453 | CLR((tp)->t_flags, TF_TMR_KEEP)(((tp)->t_flags) &= ~(0x10000000U)); |
| 454 | |
| 455 | if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG0x0001) { |
| 456 | otp = tp; |
| 457 | ostate = tp->t_state; |
| 458 | } |
| 459 | tcpstat_inc(tcps_keeptimeo); |
| 460 | if (TCPS_HAVEESTABLISHED(tp->t_state)((tp->t_state) >= 4) == 0) |
| 461 | goto dropit; |
| 462 | if ((tcp_always_keepalive || |
| 463 | tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE0x0008) && |
| 464 | tp->t_state <= TCPS_CLOSING7) { |
| 465 | int maxidle; |
| 466 | uint64_t now; |
| 467 | |
| 468 | maxidle = READ_ONCE(tcp_maxidle)({ typeof(tcp_maxidle) __tmp = *(volatile typeof(tcp_maxidle) *)&(tcp_maxidle); membar_datadep_consumer(); __tmp; }); |
| 469 | now = tcp_now(); |
| 470 | if ((maxidle > 0) && |
| 471 | ((now - tp->t_rcvtime) >= tcp_keepidle + maxidle)) |
| 472 | goto dropit; |
| 473 | /* |
| 474 | * Send a packet designed to force a response |
| 475 | * if the peer is up and reachable: |
| 476 | * either an ACK if the connection is still alive, |
| 477 | * or an RST if the peer has closed the connection |
| 478 | * due to timeout or reboot. |
| 479 | * Using sequence number tp->snd_una-1 |
| 480 | * causes the transmitted zero-length segment |
| 481 | * to lie outside the receive window; |
| 482 | * by the protocol spec, this requires the |
| 483 | * correspondent TCP to respond. |
| 484 | */ |
| 485 | tcpstat_inc(tcps_keepprobe); |
| 486 | tcp_respond(tp, mtod(tp->t_template, caddr_t)((caddr_t)((tp->t_template)->m_hdr.mh_data)), |
| 487 | NULL((void *)0), tp->rcv_nxt, tp->snd_una - 1, 0, 0, now); |
| 488 | TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepintvl)do { (((tp)->t_flags) |= (0x04000000U << (2))); timeout_add_msec (&(tp)->t_timer[(2)], (tcp_keepintvl)); } while (0); |
| 489 | } else |
| 490 | TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle)do { (((tp)->t_flags) |= (0x04000000U << (2))); timeout_add_msec (&(tp)->t_timer[(2)], (tcp_keepidle)); } while (0); |
| 491 | if (otp) |
| 492 | tcp_trace(TA_TIMER5, ostate, tp, otp, NULL((void *)0), TCPT_KEEP2, 0); |
| 493 | out: |
| 494 | NET_UNLOCK()do { rw_exit_write(&netlock); } while (0); |
| 495 | return; |
| 496 | |
| 497 | dropit: |
| 498 | tcpstat_inc(tcps_keepdrops); |
| 499 | tp = tcp_drop(tp, ETIMEDOUT60); |
Value stored to 'tp' is never read | |
| 500 | NET_UNLOCK()do { rw_exit_write(&netlock); } while (0); |
| 501 | } |
| 502 | |
| 503 | void |
| 504 | tcp_timer_2msl(void *arg) |
| 505 | { |
| 506 | struct tcpcb *otp = NULL((void *)0), *tp = arg; |
| 507 | short ostate; |
| 508 | int maxidle; |
| 509 | uint64_t now; |
| 510 | |
| 511 | NET_LOCK()do { rw_enter_write(&netlock); } while (0); |
| 512 | /* Ignore canceled timeouts or timeouts that have been rescheduled. */ |
| 513 | if (!ISSET((tp)->t_flags, TF_TMR_2MSL)(((tp)->t_flags) & (0x20000000U)) || |
| 514 | timeout_pending(&tp->t_timer[TCPT_2MSL])((&tp->t_timer[3])->to_flags & 0x02)) |
| 515 | goto out; |
| 516 | CLR((tp)->t_flags, TF_TMR_2MSL)(((tp)->t_flags) &= ~(0x20000000U)); |
| 517 | |
| 518 | if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG0x0001) { |
| 519 | otp = tp; |
| 520 | ostate = tp->t_state; |
| 521 | } |
| 522 | tcp_timer_freesack(tp); |
| 523 | |
| 524 | maxidle = READ_ONCE(tcp_maxidle)({ typeof(tcp_maxidle) __tmp = *(volatile typeof(tcp_maxidle) *)&(tcp_maxidle); membar_datadep_consumer(); __tmp; }); |
| 525 | now = tcp_now(); |
| 526 | if (tp->t_state != TCPS_TIME_WAIT10 && |
| 527 | ((maxidle == 0) || ((now - tp->t_rcvtime) <= maxidle))) |
| 528 | TCP_TIMER_ARM(tp, TCPT_2MSL, tcp_keepintvl)do { (((tp)->t_flags) |= (0x04000000U << (3))); timeout_add_msec (&(tp)->t_timer[(3)], (tcp_keepintvl)); } while (0); |
| 529 | else |
| 530 | tp = tcp_close(tp); |
| 531 | if (otp) |
| 532 | tcp_trace(TA_TIMER5, ostate, tp, otp, NULL((void *)0), TCPT_2MSL3, 0); |
| 533 | out: |
| 534 | NET_UNLOCK()do { rw_exit_write(&netlock); } while (0); |
| 535 | } |
| 536 | |
| 537 | void |
| 538 | tcp_timer_reaper(void *arg) |
| 539 | { |
| 540 | struct tcpcb *tp = arg; |
| 541 | |
| 542 | /* |
| 543 | * This timer is necessary to delay the pool_put() after all timers |
| 544 | * have finished, even if they were sleeping to grab the net lock. |
| 545 | * Putting the pool_put() in a timer is sufficient as all timers run |
| 546 | * from the same timeout thread. Note that neither softnet thread nor |
| 547 | * user process may access the tcpcb after arming the reaper timer. |
| 548 | * Freeing may run in parallel as it does not grab the net lock. |
| 549 | */ |
| 550 | pool_put(&tcpcb_pool, tp); |
| 551 | tcpstat_inc(tcps_closed); |
| 552 | } |