tcp_timer.c revision 534aa84173051cab039a0585eee5b5dd011b20b8
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync/*
9eb499828dd875d229531b50d05f016b8a1f1dd9vboxsync * Copyright (c) 1982, 1986, 1988, 1990, 1993
365b40dec2ed01d9983d29e276e7431c5a4a9c18vboxsync * The Regents of the University of California. All rights reserved.
9eb499828dd875d229531b50d05f016b8a1f1dd9vboxsync *
9eb499828dd875d229531b50d05f016b8a1f1dd9vboxsync * Redistribution and use in source and binary forms, with or without
9eb499828dd875d229531b50d05f016b8a1f1dd9vboxsync * modification, are permitted provided that the following conditions
9eb499828dd875d229531b50d05f016b8a1f1dd9vboxsync * are met:
9eb499828dd875d229531b50d05f016b8a1f1dd9vboxsync * 1. Redistributions of source code must retain the above copyright
9eb499828dd875d229531b50d05f016b8a1f1dd9vboxsync * notice, this list of conditions and the following disclaimer.
9eb499828dd875d229531b50d05f016b8a1f1dd9vboxsync * 2. Redistributions in binary form must reproduce the above copyright
9eb499828dd875d229531b50d05f016b8a1f1dd9vboxsync * notice, this list of conditions and the following disclaimer in the
9eb499828dd875d229531b50d05f016b8a1f1dd9vboxsync * documentation and/or other materials provided with the distribution.
9eb499828dd875d229531b50d05f016b8a1f1dd9vboxsync * 3. All advertising materials mentioning features or use of this software
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * must display the following acknowledgement:
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * This product includes software developed by the University of
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * California, Berkeley and its contributors.
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * 4. Neither the name of the University nor the names of its contributors
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * may be used to endorse or promote products derived from this software
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * without specific prior written permission.
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync *
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
8eb4989e815c8f374b965265ccf184d6ce17d9e8vboxsync * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
da6747c2419b9cea8b5e2c576a30a5de999a8ab3vboxsync * SUCH DAMAGE.
da6747c2419b9cea8b5e2c576a30a5de999a8ab3vboxsync *
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * @(#)tcp_timer.c 8.1 (Berkeley) 6/10/93
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * tcp_timer.c,v 1.2 1994/08/02 07:49:10 davidg Exp
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync */
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync
da6747c2419b9cea8b5e2c576a30a5de999a8ab3vboxsync#include <slirp.h>
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync
46e6cceda24bf6c589e4cb151afefe4fffecca7bvboxsync/*
8eb4989e815c8f374b965265ccf184d6ce17d9e8vboxsync * Fast timeout routine for processing delayed acks
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync */
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsyncvoid
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsynctcp_fasttimo(PNATState pData)
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync{
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync register struct socket *so;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync register struct tcpcb *tp;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync#ifdef VBOX_WITH_SYNC_SLIRP
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync struct socket *so_next;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync#endif
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync DEBUG_CALL("tcp_fasttimo");
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync VBOX_SLIRP_LOCK(pData->tcb_mutex);
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync so = tcb.so_next;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync#ifndef VBOX_WITH_SYNC_SLIRP
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync if (so)
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync for (; so != &tcb; so = so->so_next) {
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync#else
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync while(1) {
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync if ( so == &tcb) {
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync VBOX_SLIRP_UNLOCK(pData->tcb_mutex);
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync break;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync }
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync so_next = so->so_next;
27efd9329f6a90f7cacf840031e5305f98975960vboxsync VBOX_SLIRP_LOCK(so->so_mutex);
27efd9329f6a90f7cacf840031e5305f98975960vboxsync VBOX_SLIRP_UNLOCK(pData->tcb_mutex);
27efd9329f6a90f7cacf840031e5305f98975960vboxsync#endif
da6747c2419b9cea8b5e2c576a30a5de999a8ab3vboxsync if ((tp = (struct tcpcb *)so->so_tcpcb) &&
0a724db1030736c131a45392c0ebb6bb25362917vboxsync (tp->t_flags & TF_DELACK)) {
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync tp->t_flags &= ~TF_DELACK;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync tp->t_flags |= TF_ACKNOW;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync tcpstat.tcps_delack++;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync (void) tcp_output(pData, tp);
37a84692e27b34ed2141b208bf3ab7f9f90bb422vboxsync }
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync VBOX_SLIRP_LOCK(pData->tcb_mutex);
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync VBOX_SLIRP_UNLOCK(so->so_mutex);
27efd9329f6a90f7cacf840031e5305f98975960vboxsync#ifdef VBOX_WITH_SYNC_SLIRP
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync so = so_next;
ad34209dccf31d54e2277d732a90ce6ea4374362vboxsync#endif
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync }
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync}
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync/*
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * Tcp protocol timeout routine called every 500 ms.
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * Updates the timers in all active tcb's and
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * causes finite state machine actions if timers expire.
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync */
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsyncvoid
27efd9329f6a90f7cacf840031e5305f98975960vboxsynctcp_slowtimo(PNATState pData)
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync{
ad34209dccf31d54e2277d732a90ce6ea4374362vboxsync register struct socket *ip, *ipnxt;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync register struct tcpcb *tp;
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync register int i;
da6747c2419b9cea8b5e2c576a30a5de999a8ab3vboxsync
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync DEBUG_CALL("tcp_slowtimo");
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync /*
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * Search through tcb's and update active timers.
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync */
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync VBOX_SLIRP_LOCK(pData->tcb_mutex);
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync ip = tcb.so_next;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync#ifndef VBOX_WITH_SYNC_SLIRP
27efd9329f6a90f7cacf840031e5305f98975960vboxsync if (ip == 0)
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync return;
ad34209dccf31d54e2277d732a90ce6ea4374362vboxsync for (; ip != &tcb; ip = ipnxt) {
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync#else
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync if (ip == NULL) {
27efd9329f6a90f7cacf840031e5305f98975960vboxsync VBOX_SLIRP_UNLOCK(pData->tcb_mutex);
da6747c2419b9cea8b5e2c576a30a5de999a8ab3vboxsync return;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync }
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync while (1) {
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync if (ip == &tcb) {
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync VBOX_SLIRP_UNLOCK(pData->tcb_mutex);
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync break;
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync }
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync ipnxt = ip->so_next;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync VBOX_SLIRP_LOCK(ip->so_mutex);
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync VBOX_SLIRP_UNLOCK(pData->tcb_mutex);
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync#endif
27efd9329f6a90f7cacf840031e5305f98975960vboxsync ipnxt = ip->so_next;
27efd9329f6a90f7cacf840031e5305f98975960vboxsync tp = sototcpcb(ip);
27efd9329f6a90f7cacf840031e5305f98975960vboxsync if (tp == 0)
27efd9329f6a90f7cacf840031e5305f98975960vboxsync goto before_loop_ends; /*vvl:the same as continue in original code*/
27efd9329f6a90f7cacf840031e5305f98975960vboxsync for (i = 0; i < TCPT_NTIMERS; i++) {
27efd9329f6a90f7cacf840031e5305f98975960vboxsync if (tp->t_timer[i] && --tp->t_timer[i] == 0) {
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync tcp_timers(pData, tp,i);
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync if (ipnxt->so_prev != ip)
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync goto tpgone;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync }
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync }
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync tp->t_idle++;
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync if (tp->t_rtt)
c38d5dda76cee141ae524ccce2c513178be1b87cvboxsync tp->t_rtt++;
69f57565f5243a46f1df060b63d0fd830de3be04vboxsynctpgone:
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync ;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsyncbefore_loop_ends:
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync VBOX_SLIRP_LOCK(pData->tcb_mutex);
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync VBOX_SLIRP_UNLOCK(ip->so_mutex);
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync#ifdef VBOX_WITH_SYNC_SLIRP
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync ip=ipnxt;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync#endif
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync }
8eb4989e815c8f374b965265ccf184d6ce17d9e8vboxsync tcp_iss += TCP_ISSINCR/PR_SLOWHZ; /* increment iss */
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync#ifdef TCP_COMPAT_42
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync if ((int)tcp_iss < 0)
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync tcp_iss = 0; /* XXX */
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync#endif
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync tcp_now++; /* for timestamps */
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync}
4726db8b47db329039ce8f8e13ecd2c1f696fa60vboxsync
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync/*
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync * Cancel all timers for TCP tp.
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync */
da6747c2419b9cea8b5e2c576a30a5de999a8ab3vboxsyncvoid
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsynctcp_canceltimers(tp)
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync struct tcpcb *tp;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync{
9d473abea9a9b6597b2b20bedc950ba33a2e73a5vboxsync register int i;
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync for (i = 0; i < TCPT_NTIMERS; i++)
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync tp->t_timer[i] = 0;
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync}
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync
ad34209dccf31d54e2277d732a90ce6ea4374362vboxsyncconst int tcp_backoff[TCP_MAXRXTSHIFT + 1] =
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync/*
1c2c968fd241148110002d75b2c0fdeddc211e14vboxsync * TCP timer processing.
1c2c968fd241148110002d75b2c0fdeddc211e14vboxsync */
c4db4db147d491a4570d04c951c8abafeaf951dbvboxsyncstruct tcpcb *
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsynctcp_timers(PNATState pData, register struct tcpcb *tp, int timer)
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync{
9d473abea9a9b6597b2b20bedc950ba33a2e73a5vboxsync register int rexmt;
7e958a4329e4f9d83f597e26c72121969091e87bvboxsync
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync DEBUG_CALL("tcp_timers");
f3f687b00a9f7c98dc0b81899090bc5f659ae7bdvboxsync
37a84692e27b34ed2141b208bf3ab7f9f90bb422vboxsync switch (timer) {
bcc2356dccf06ea3fdd1f3e4d4e62b04e95673d0vboxsync
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync /*
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync * 2 MSL timeout in shutdown went off. If we're closed but
8eb4989e815c8f374b965265ccf184d6ce17d9e8vboxsync * still waiting for peer to close and connection has been idle
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * too long, or if 2MSL time is up from TIME_WAIT, delete connection
17a9bf5bda28580b3163cf1e2fb8b13c356b5fb0vboxsync * control block. Otherwise, check again in a bit.
8eb4989e815c8f374b965265ccf184d6ce17d9e8vboxsync */
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync case TCPT_2MSL:
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync if (tp->t_state != TCPS_TIME_WAIT &&
ad34209dccf31d54e2277d732a90ce6ea4374362vboxsync tp->t_idle <= tcp_maxidle)
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync tp->t_timer[TCPT_2MSL] = tcp_keepintvl;
8eb4989e815c8f374b965265ccf184d6ce17d9e8vboxsync else
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync tp = tcp_close(pData, tp);
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync break;
ad34209dccf31d54e2277d732a90ce6ea4374362vboxsync
ad34209dccf31d54e2277d732a90ce6ea4374362vboxsync /*
8eb4989e815c8f374b965265ccf184d6ce17d9e8vboxsync * Retransmission timer went off. Message has not
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync * been acked within retransmit interval. Back off
9d473abea9a9b6597b2b20bedc950ba33a2e73a5vboxsync * to a longer retransmit interval and retransmit one segment.
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync */
9d473abea9a9b6597b2b20bedc950ba33a2e73a5vboxsync case TCPT_REXMT:
9d473abea9a9b6597b2b20bedc950ba33a2e73a5vboxsync
9d473abea9a9b6597b2b20bedc950ba33a2e73a5vboxsync /*
9d473abea9a9b6597b2b20bedc950ba33a2e73a5vboxsync * XXXXX If a packet has timed out, then remove all the queued
bcc2356dccf06ea3fdd1f3e4d4e62b04e95673d0vboxsync * packets for that session.
9d473abea9a9b6597b2b20bedc950ba33a2e73a5vboxsync */
9d473abea9a9b6597b2b20bedc950ba33a2e73a5vboxsync
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) {
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync /*
8eb4989e815c8f374b965265ccf184d6ce17d9e8vboxsync * This is a hack to suit our terminal server here at the uni of canberra
da6747c2419b9cea8b5e2c576a30a5de999a8ab3vboxsync * since they have trouble with zeroes... It usually lets them through
5b802b5e11fed6e163afca32e9118d2599d312fbvboxsync * unharmed, but under some conditions, it'll eat the zeros. If we
0b1397fff8b368cf5c2f3d8f5b312ed00114977dvboxsync * keep retransmitting it, it'll keep eating the zeroes, so we keep
5b802b5e11fed6e163afca32e9118d2599d312fbvboxsync * retransmitting, and eventually the connection dies...
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * (this only happens on incoming data)
0b1397fff8b368cf5c2f3d8f5b312ed00114977dvboxsync *
bcc2356dccf06ea3fdd1f3e4d4e62b04e95673d0vboxsync * So, if we were gonna drop the connection from too many retransmits,
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * don't... instead halve the t_maxseg, which might break up the NULLs and
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * let them through
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync *
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * *sigh*
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync */
da6747c2419b9cea8b5e2c576a30a5de999a8ab3vboxsync
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync tp->t_maxseg >>= 1;
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync if (tp->t_maxseg < 32) {
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync /*
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync * We tried our best, now the connection must die!
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync */
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync tp->t_rxtshift = TCP_MAXRXTSHIFT;
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync tcpstat.tcps_timeoutdrop++;
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync tp = tcp_drop(pData, tp, tp->t_softerror);
bbfc28b1a00ce00001b2ead074d47254bec3e5cfvboxsync /* tp->t_softerror : ETIMEDOUT); */ /* XXX */
da6747c2419b9cea8b5e2c576a30a5de999a8ab3vboxsync return (tp); /* XXX */
da6747c2419b9cea8b5e2c576a30a5de999a8ab3vboxsync }
ad34209dccf31d54e2277d732a90ce6ea4374362vboxsync
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync /*
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * Set rxtshift to 6, which is still at the maximum
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * backoff time
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync */
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync tp->t_rxtshift = 6;
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync }
20b950300ed7ebcdf78f414c3d98b20d010ff74fvboxsync tcpstat.tcps_rexmttimeo++;
702250abf86d6252cfbbff216d848d2c799548a4vboxsync rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
27efd9329f6a90f7cacf840031e5305f98975960vboxsync TCPT_RANGESET(tp->t_rxtcur, rexmt,
27efd9329f6a90f7cacf840031e5305f98975960vboxsync (short)tp->t_rttmin, TCPTV_REXMTMAX); /* XXX */
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync /*
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * If losing, let the lower level know and try for
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * a better route. Also, if we backed off this far,
6be66de4257f4f564e35f7b8ee57a282e3cf3e96vboxsync * our srtt estimate is probably bogus. Clobber it
* so we'll take the next rtt measurement as our srtt;
* move the current srtt into rttvar to keep the current
* retransmit times until then.
*/
if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) {
/* in_losing(tp->t_inpcb); */
tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT);
tp->t_srtt = 0;
}
tp->snd_nxt = tp->snd_una;
/*
* If timing a segment in this window, stop the timer.
*/
tp->t_rtt = 0;
/*
* Close the congestion window down to one segment
* (we'll open it by one segment for each ack we get).
* Since we probably have a window's worth of unacked
* data accumulated, this "slow start" keeps us from
* dumping all that data as back-to-back packets (which
* might overwhelm an intermediate gateway).
*
* There are two phases to the opening: Initially we
* open by one mss on each ack. This makes the window
* size increase exponentially with time. If the
* window is larger than the path can handle, this
* exponential growth results in dropped packet(s)
* almost immediately. To get more time between
* drops but still "push" the network to take advantage
* of improving conditions, we switch from exponential
* to linear window opening at some threshold size.
* For a threshold, we use half the current window
* size, truncated to a multiple of the mss.
*
* (the minimum cwnd that will give us exponential
* growth is 2 mss. We don't allow the threshold
* to go below this.)
*/
{
u_int win = min(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_maxseg;
if (win < 2)
win = 2;
tp->snd_cwnd = tp->t_maxseg;
tp->snd_ssthresh = win * tp->t_maxseg;
tp->t_dupacks = 0;
}
(void) tcp_output(pData, tp);
break;
/*
* Persistence timer into zero window.
* Force a byte to be output, if possible.
*/
case TCPT_PERSIST:
tcpstat.tcps_persisttimeo++;
tcp_setpersist(tp);
tp->t_force = 1;
(void) tcp_output(pData, tp);
tp->t_force = 0;
break;
/*
* Keep-alive timer went off; send something
* or drop connection if idle for too long.
*/
case TCPT_KEEP:
tcpstat.tcps_keeptimeo++;
if (tp->t_state < TCPS_ESTABLISHED)
goto dropit;
/* if (tp->t_socket->so_options & SO_KEEPALIVE && */
if ((so_options) && tp->t_state <= TCPS_CLOSE_WAIT) {
if (tp->t_idle >= tcp_keepidle + tcp_maxidle)
goto dropit;
/*
* Send a packet designed to force a response
* if the peer is up and reachable:
* either an ACK if the connection is still alive,
* or an RST if the peer has closed the connection
* due to timeout or reboot.
* Using sequence number tp->snd_una-1
* causes the transmitted zero-length segment
* to lie outside the receive window;
* by the protocol spec, this requires the
* correspondent TCP to respond.
*/
tcpstat.tcps_keepprobe++;
#ifdef TCP_COMPAT_42
/*
* The keepalive packet must have nonzero length
* to get a 4.2 host to respond.
*/
tcp_respond(tp, &tp->t_template, (struct mbuf *)NULL,
tp->rcv_nxt - 1, tp->snd_una - 1, 0);
#else
tcp_respond(pData, tp, &tp->t_template, (struct mbuf *)NULL,
tp->rcv_nxt, tp->snd_una - 1, 0);
#endif
tp->t_timer[TCPT_KEEP] = tcp_keepintvl;
} else
tp->t_timer[TCPT_KEEP] = tcp_keepidle;
break;
dropit:
tcpstat.tcps_keepdrops++;
tp = tcp_drop(pData, tp, 0); /* ETIMEDOUT); */
break;
}
return (tp);
}