diff options
Diffstat (limited to 'slirp/src/tcp_timer.c')
| -rw-r--r-- | slirp/src/tcp_timer.c | 294 |
1 files changed, 0 insertions, 294 deletions
diff --git a/slirp/src/tcp_timer.c b/slirp/src/tcp_timer.c deleted file mode 100644 index be361a1bb6..0000000000 --- a/slirp/src/tcp_timer.c +++ /dev/null @@ -1,294 +0,0 @@ -/* SPDX-License-Identifier: BSD-3-Clause */ -/* - * 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 "slirp.h" - -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 the zeroes, so we keep - * retransmitting, and eventually the connection dies... - * (this only happens on incoming data) - * - * So, if we were gonna drop the connection from too many retransmits, - * don't... instead halve the t_maxseg, which might break up the NULLs and - * let them through - * - * *sigh* - */ - - tp->t_maxseg >>= 1; - if (tp->t_maxseg < 32) { - /* - * We tried our best, now the connection must die! - */ - tp->t_rxtshift = TCP_MAXRXTSHIFT; - tp = tcp_drop(tp, tp->t_softerror); - /* tp->t_softerror : ETIMEDOUT); */ /* XXX */ - return (tp); /* XXX */ - } - - /* - * Set rxtshift to 6, which is still at the maximum - * backoff time - */ - tp->t_rxtshift = 6; - } - rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift]; - TCPT_RANGESET(tp->t_rxtcur, rexmt, - (short)tp->t_rttmin, TCPTV_REXMTMAX); /* XXX */ - tp->t_timer[TCPT_REXMT] = tp->t_rxtcur; - /* - * If losing, let the lower level know and try for - * a better route. Also, if we backed off this far, - * 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) { - 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.) - */ - { - unsigned 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(tp); - break; - - /* - * Persistence timer into zero window. - * Force a byte to be output, if possible. - */ - case TCPT_PERSIST: - tcp_setpersist(tp); - tp->t_force = 1; - (void) tcp_output(tp); - tp->t_force = 0; - break; - - /* - * Keep-alive timer went off; send something - * or drop connection if idle for too long. - */ - case TCPT_KEEP: - if (tp->t_state < TCPS_ESTABLISHED) - goto dropit; - - if (slirp_do_keepalive && tp->t_state <= TCPS_CLOSE_WAIT) { - if (tp->t_idle >= TCPTV_KEEP_IDLE + 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. - */ - tcp_respond(tp, &tp->t_template, (struct mbuf *)NULL, - tp->rcv_nxt, tp->snd_una - 1, 0, - tp->t_socket->so_ffamily); - tp->t_timer[TCPT_KEEP] = TCPTV_KEEPINTVL; - } else - tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_IDLE; - break; - - dropit: - tp = tcp_drop(tp, 0); - break; - } - - return (tp); -} |