/* * Copyright (c) 1982, 1986, 1988, 1990, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)tcp_timer.c 8.1 (Berkeley) 6/10/93 * tcp_timer.c,v 1.2 1994/08/02 07:49:10 davidg Exp */ #include "qemu/osdep.h" #include static struct tcpcb *tcp_timers(register struct tcpcb *tp, int timer); /* * Fast timeout routine for processing delayed acks */ void tcp_fasttimo(Slirp *slirp) { register struct socket *so; register struct tcpcb *tp; DEBUG_CALL("tcp_fasttimo"); so = slirp->tcb.so_next; if (so) for (; so != &slirp->tcb; so = so->so_next) if ((tp = (struct tcpcb *)so->so_tcpcb) && (tp->t_flags & TF_DELACK)) { tp->t_flags &= ~TF_DELACK; tp->t_flags |= TF_ACKNOW; (void) tcp_output(tp); } } /* * Tcp protocol timeout routine called every 500 ms. * Updates the timers in all active tcb's and * causes finite state machine actions if timers expire. */ void tcp_slowtimo(Slirp *slirp) { register struct socket *ip, *ipnxt; register struct tcpcb *tp; register int i; DEBUG_CALL("tcp_slowtimo"); /* * Search through tcb's and update active timers. */ ip = slirp->tcb.so_next; if (ip == NULL) { return; } for (; ip != &slirp->tcb; ip = ipnxt) { ipnxt = ip->so_next; tp = sototcpcb(ip); if (tp == NULL) { continue; } for (i = 0; i < TCPT_NTIMERS; i++) { if (tp->t_timer[i] && --tp->t_timer[i] == 0) { tcp_timers(tp,i); if (ipnxt->so_prev != ip) goto tpgone; } } tp->t_idle++; if (tp->t_rtt) tp->t_rtt++; tpgone: ; } slirp->tcp_iss += TCP_ISSINCR/PR_SLOWHZ; /* increment iss */ slirp->tcp_now++; /* for timestamps */ } /* * Cancel all timers for TCP tp. */ void tcp_canceltimers(struct tcpcb *tp) { register int i; for (i = 0; i < TCPT_NTIMERS; i++) tp->t_timer[i] = 0; } const int tcp_backoff[TCP_MAXRXTSHIFT + 1] = { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 }; /* * TCP timer processing. */ static struct tcpcb * tcp_timers(register struct tcpcb *tp, int timer) { register int rexmt; DEBUG_CALL("tcp_timers"); switch (timer) { /* * 2 MSL timeout in shutdown went off. If we're closed but * still waiting for peer to close and connection has been idle * too long, or if 2MSL time is up from TIME_WAIT, delete connection * control block. Otherwise, check again in a bit. */ case TCPT_2MSL: if (tp->t_state != TCPS_TIME_WAIT && tp->t_idle <= TCP_MAXIDLE) tp->t_timer[TCPT_2MSL] = TCPTV_KEEPINTVL; else tp = tcp_close(tp); break; /* * Retransmission timer went off. Message has not * been acked within retransmit interval. Back off * to a longer retransmit interval and retransmit one segment. */ case TCPT_REXMT: /* * XXXXX If a packet has timed out, then remove all the queued * packets for that session. */ if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { /* * This is a hack to suit our terminal server here at the uni of canberra * since they have trouble with zeroes... It usually lets them through * unharmed, but under some conditions, it'll eat the zeros. If we * keep retransmitting it, it'll keep eating