-/* tcp_timer.c 4.21 82/06/08 */
-
-#include "../h/param.h"
-#include "../h/systm.h"
-#include "../h/mbuf.h"
-#include "../h/socket.h"
-#include "../h/socketvar.h"
-#include "../h/protosw.h"
-#include "../net/in.h"
-#include "../net/route.h"
-#include "../net/in_pcb.h"
-#include "../net/in_systm.h"
+/*
+ * Copyright (c) 1982, 1986 Regents of the University of California.
+ * All rights reserved. The Berkeley software License Agreement
+ * specifies the terms and conditions for redistribution.
+ *
+ * @(#)tcp_timer.c 7.8 (Berkeley) %G%
+ */
+
+#include "param.h"
+#include "systm.h"
+#include "mbuf.h"
+#include "socket.h"
+#include "socketvar.h"
+#include "protosw.h"
+#include "errno.h"
+
#include "../net/if.h"
-#include "../net/ip.h"
-#include "../net/ip_var.h"
-#include "../net/tcp.h"
-#include "../net/tcp_fsm.h"
-#include "../net/tcp_seq.h"
-#include "../net/tcp_timer.h"
-#include "../net/tcp_var.h"
-#include "../net/tcpip.h"
-#include "../errno.h"
+#include "../net/route.h"
+
+#include "in.h"
+#include "in_pcb.h"
+#include "in_systm.h"
+#include "ip.h"
+#include "ip_var.h"
+#include "tcp.h"
+#include "tcp_fsm.h"
+#include "tcp_seq.h"
+#include "tcp_timer.h"
+#include "tcp_var.h"
+#include "tcpip.h"
int tcpnodelack = 0;
/*
register struct inpcb *inp;
register struct tcpcb *tp;
int s = splnet();
-COUNT(TCP_FASTTIMO);
inp = tcb.inp_next;
if (inp)
(tp->t_flags & TF_DELACK)) {
tp->t_flags &= ~TF_DELACK;
tp->t_flags |= TF_ACKNOW;
+ tcpstat.tcps_delack++;
(void) tcp_output(tp);
}
splx(s);
register struct tcpcb *tp;
int s = splnet();
register int i;
-COUNT(TCP_SLOWTIMO);
/*
* Search through tcb's and update active timers.
splx(s);
return;
}
- while (ip != &tcb) {
+ for (; ip != &tcb; ip = ipnxt) {
+ ipnxt = ip->inp_next;
tp = intotcpcb(ip);
if (tp == 0)
continue;
- ipnxt = ip->inp_next;
for (i = 0; i < TCPT_NTIMERS; i++) {
if (tp->t_timer[i] && --tp->t_timer[i] == 0) {
(void) tcp_usrreq(tp->t_inpcb->inp_socket,
PRU_SLOWTIMO, (struct mbuf *)0,
- (caddr_t)i);
+ (struct mbuf *)i, (struct mbuf *)0);
if (ipnxt->inp_prev != ip)
goto tpgone;
}
if (tp->t_rtt)
tp->t_rtt++;
tpgone:
- ip = ipnxt;
+ ;
}
tcp_iss += TCP_ISSINCR/PR_SLOWHZ; /* increment iss */
+#ifdef TCP_COMPAT_42
+ if ((int)tcp_iss < 0)
+ tcp_iss = 0; /* XXX */
+#endif
splx(s);
}
{
register int i;
-COUNT(TCP_CANCELTIMERS);
for (i = 0; i < TCPT_NTIMERS; i++)
tp->t_timer[i] = 0;
}
-float tcp_backoff[TCP_MAXRXTSHIFT] =
- { 1.0, 1.2, 1.4, 1.7, 2.0, 3.0, 5.0, 8.0, 16.0, 32.0 };
-int tcprexmtprint = 0;
-int tcpexprexmtbackoff = 0;
+int tcp_backoff[TCP_MAXRXTSHIFT] =
+ { 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
+
+int tcp_keeplen = 1; /* must be nonzero for 4.2 compat- XXX */
+
/*
* TCP timer processing.
*/
+struct tcpcb *
tcp_timers(tp, timer)
register struct tcpcb *tp;
int timer;
{
+ register int rexmt;
-COUNT(TCP_TIMERS);
switch (timer) {
/*
- * 2 MSL timeout in shutdown went off. Delete connection
- * control block.
+ * 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:
- tcp_close(tp);
- return;
+ if (tp->t_state != TCPS_TIME_WAIT &&
+ tp->t_idle <= TCPTV_MAXIDLE)
+ tp->t_timer[TCPT_2MSL] = TCPTV_KEEP;
+ 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 all
- * unacknowledged messages in the window.
+ * to a longer retransmit interval and retransmit one segment.
*/
case TCPT_REXMT:
- tp->t_rxtshift++;
- if (tp->t_rxtshift > TCP_MAXRXTSHIFT) {
- tcp_drop(tp, ETIMEDOUT);
- return;
- }
- TCPT_RANGESET(tp->t_timer[TCPT_REXMT],
- (int)tp->t_srtt, TCPTV_MIN, TCPTV_MAX);
- if (tcpexprexmtbackoff) {
- TCPT_RANGESET(tp->t_timer[TCPT_REXMT],
- tp->t_timer[TCPT_REXMT] << tp->t_rxtshift,
- TCPTV_MIN, TCPTV_MAX);
- } else {
- TCPT_RANGESET(tp->t_timer[TCPT_REXMT],
- tp->t_timer[TCPT_REXMT] *
- tcp_backoff[tp->t_rxtshift - 1],
- TCPTV_MIN, TCPTV_MAX);
+ if (tp->t_rxtshift >= TCP_MAXRXTSHIFT) {
+ tcpstat.tcps_timeoutdrop++;
+ tp = tcp_drop(tp, ETIMEDOUT);
+ break;
}
-if (tcprexmtprint)
-printf("rexmt set to %d\n", tp->t_timer[TCPT_REXMT]);
+ tcpstat.tcps_rexmttimeo++;
+ rexmt = ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1;
+ rexmt *= tcp_backoff[tp->t_rxtshift];
+ tp->t_rxtshift++;
+ TCPT_RANGESET(tp->t_timer[TCPT_REXMT], rexmt,
+ TCPTV_MIN, TCPTV_REXMTMAX);
+ /*
+ * If losing, let the lower level know
+ * and try for a better route.
+ */
+ if (tp->t_rxtshift >= TCP_MAXRXTSHIFT / 4 ||
+ rexmt >= 10 * PR_SLOWHZ)
+ in_losing(tp->t_inpcb);
tp->snd_nxt = tp->snd_una;
- /* this only transmits one segment! */
+ /*
+ * 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).
+ */
+ tp->snd_cwnd = tp->t_maxseg;
(void) tcp_output(tp);
- return;
+ break;
/*
* Persistance 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(tp);
tp->t_force = 0;
- return;
+ 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_inpcb->inp_socket->so_options & SO_KEEPALIVE) {
+ if (tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE &&
+ tp->t_state <= TCPS_CLOSE_WAIT) {
if (tp->t_idle >= TCPTV_MAXIDLE)
goto dropit;
/*
- * Saying tp->rcv_nxt-1 lies about what
- * we have received, and by the protocol spec
- * requires the correspondent TCP to respond.
- * Saying tp->snd_una-1 causes the transmitted
- * byte to lie outside the receive window; this
- * is important because we don't necessarily
- * have a byte in the window to send (consider
- * a one-way stream!)
+ * 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, tp->rcv_nxt-1, tp->snd_una-1, 0);
- } else
- tp->t_idle = 0;
+ tcp_respond(tp, tp->t_template,
+ tp->rcv_nxt - 1, tp->snd_una - 1, 0);
+#else
+ tcp_respond(tp, tp->t_template,
+ tp->rcv_nxt, tp->snd_una - 1, 0);
+#endif
+ }
tp->t_timer[TCPT_KEEP] = TCPTV_KEEP;
- return;
+ break;
dropit:
- tcp_drop(tp, ETIMEDOUT);
- return;
-
-#ifdef TCPTRUEOOB
- /*
- * Out-of-band data retransmit timer.
- */
- case TCPT_OOBREXMT:
- if (tp->t_flags & TF_NOOPT)
- return;
- (void) tcp_output(tp);
- TCPT_RANGESET(tp->t_timer[TCPT_OOBREXMT],
- 2 * tp->t_srtt, TCPTV_MIN, TCPTV_MAX);
- return;
-#endif
+ tcpstat.tcps_keepdrops++;
+ tp = tcp_drop(tp, ETIMEDOUT);
+ break;
}
+ return (tp);
}