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[unix-history] / usr / src / sys / netinet / tcp_timer.c
diff --git a/usr/src/sys/netinet/tcp_timer.c b/usr/src/sys/netinet/tcp_timer.c
index dc40da3..524d67f 100644 (file)
--- a/usr/src/sys/netinet/tcp_timer.c
+++ b/usr/src/sys/netinet/tcp_timer.c
@@ -1,26 +1,35 @@
-/* tcp_timer.c 4.11 82/01/13 */
+/*
+ * Copyright (c) 1982 Regents of the University of California.
+ * All rights reserved.  The Berkeley software License Agreement
+ * specifies the terms and conditions for redistribution.
+ *
+ *     @(#)tcp_timer.c 6.7 (Berkeley) %G%
+ */
+
+#include "param.h"
+#include "systm.h"
+#include "mbuf.h"
+#include "socket.h"
+#include "socketvar.h"
+#include "protosw.h"
+#include "errno.h"
 
 
-#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/in_pcb.h"
-#include "../net/in_systm.h"
 #include "../net/if.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    tcpdelack = 0;
+int    tcpnodelack = 0;
 /*
  * Fast timeout routine for processing delayed acks
  */
 /*
  * Fast timeout routine for processing delayed acks
  */
@@ -29,9 +38,10 @@ tcp_fasttimo()
        register struct inpcb *inp;
        register struct tcpcb *tp;
        int s = splnet();
        register struct inpcb *inp;
        register struct tcpcb *tp;
        int s = splnet();
-COUNT(TCP_FASTTIMO);
 
 
-       for (inp = tcb.inp_next; inp != &tcb; inp = inp->inp_next)
+       inp = tcb.inp_next;
+       if (inp)
+       for (; inp != &tcb; inp = inp->inp_next)
                if ((tp = (struct tcpcb *)inp->inp_ppcb) &&
                    (tp->t_flags & TF_DELACK)) {
                        tp->t_flags &= ~TF_DELACK;
                if ((tp = (struct tcpcb *)inp->inp_ppcb) &&
                    (tp->t_flags & TF_DELACK)) {
                        tp->t_flags &= ~TF_DELACK;
@@ -48,11 +58,10 @@ COUNT(TCP_FASTTIMO);
  */
 tcp_slowtimo()
 {
  */
 tcp_slowtimo()
 {
-       register struct inpcb *ip;
+       register struct inpcb *ip, *ipnxt;
        register struct tcpcb *tp;
        int s = splnet();
        register int i;
        register struct tcpcb *tp;
        int s = splnet();
        register int i;
-COUNT(TCP_SLOWTIMO);
 
        /*
         * Search through tcb's and update active timers.
 
        /*
         * Search through tcb's and update active timers.
@@ -62,19 +71,25 @@ COUNT(TCP_SLOWTIMO);
                splx(s);
                return;
        }
                splx(s);
                return;
        }
-       for (; ip != &tcb; ip = ip->inp_next) {
+       for (; ip != &tcb; ip = ipnxt) {
+               ipnxt = ip->inp_next;
                tp = intotcpcb(ip);
                if (tp == 0)
                        continue;
                for (i = 0; i < TCPT_NTIMERS; i++) {
                tp = intotcpcb(ip);
                if (tp == 0)
                        continue;
                for (i = 0; i < TCPT_NTIMERS; i++) {
-                       if (tp->t_timer[i] && --tp->t_timer[i] == 0)
+                       if (tp->t_timer[i] && --tp->t_timer[i] == 0) {
                                (void) tcp_usrreq(tp->t_inpcb->inp_socket,
                                    PRU_SLOWTIMO, (struct mbuf *)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;
+                       }
                }
                tp->t_idle++;
                if (tp->t_rtt)
                        tp->t_rtt++;
                }
                tp->t_idle++;
                if (tp->t_rtt)
                        tp->t_rtt++;
+tpgone:
+               ;
        }
        tcp_iss += TCP_ISSINCR/PR_SLOWHZ;               /* increment iss */
        splx(s);
        }
        tcp_iss += TCP_ISSINCR/PR_SLOWHZ;               /* increment iss */
        splx(s);
@@ -88,20 +103,22 @@ tcp_canceltimers(tp)
 {
        register int i;
 
 {
        register int i;
 
-COUNT(TCP_CANCELTIMERS);
        for (i = 0; i < TCPT_NTIMERS; i++)
                tp->t_timer[i] = 0;
 }
 
        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    tcpexprexmtbackoff = 0;
 /*
  * TCP timer processing.
  */
 /*
  * TCP timer processing.
  */
+struct tcpcb *
 tcp_timers(tp, timer)
        register struct tcpcb *tp;
        int timer;
 {
 
 tcp_timers(tp, timer)
        register struct tcpcb *tp;
        int timer;
 {
 
-COUNT(TCP_TIMERS);
        switch (timer) {
 
        /*
        switch (timer) {
 
        /*
@@ -109,61 +126,89 @@ COUNT(TCP_TIMERS);
         * control block.
         */
        case TCPT_2MSL:
         * control block.
         */
        case TCPT_2MSL:
-               tcp_close(tp);
-               return;
+               tp = tcp_close(tp);
+               break;
 
        /*
         * Retransmission timer went off.  Message has not
         * been acked within retransmit interval.  Back off
 
        /*
         * 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++;
         */
        case TCPT_REXMT:
                tp->t_rxtshift++;
+               if (tp->t_rxtshift > TCP_MAXRXTSHIFT) {
+                       tp = tcp_drop(tp, ETIMEDOUT);
+                       break;
+               }
+               /*
+                * If losing, let the lower level know
+                * and try for a better route.
+                */
+               if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 2)
+                       in_rtchange(tp->t_inpcb);
                TCPT_RANGESET(tp->t_timer[TCPT_REXMT],
                TCPT_RANGESET(tp->t_timer[TCPT_REXMT],
-                   ((int)(2 * tp->t_srtt)),
-                   TCPTV_MIN, TCPTV_MAX);
-               TCPT_RANGESET(tp->t_timer[TCPT_REXMT],
-                   tp->t_timer[TCPT_REXMT] << tp->t_rxtshift,
-                   TCPTV_MIN, TCPTV_MAX);
-               if (tp->t_timer[TCPT_REXMT] > TCPTV_MAXIDLE / 2) {
-                       tcp_drop(tp, ETIMEDOUT);
-                       return;
+                   (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);
                }
                }
-printf("rexmt set to %d\n", tp->t_timer[TCPT_REXMT]);
                tp->snd_nxt = tp->snd_una;
                tp->snd_nxt = tp->snd_una;
-               /* this only transmits one segment! */
+               /*
+                * If timing a segment in this window,
+                * and we have already gotten some timing estimate,
+                * stop the timer.
+                */
+               if (tp->t_rtt && tp->t_srtt)
+                       tp->t_rtt = 0;
                (void) tcp_output(tp);
                (void) tcp_output(tp);
-               return;
+               break;
 
        /*
         * Persistance timer into zero window.
         * Force a byte to be output, if possible.
         */
        case TCPT_PERSIST:
 
        /*
         * Persistance 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;
                tp->t_force = 1;
                (void) tcp_output(tp);
                tp->t_force = 0;
-               TCPT_RANGESET(tp->t_timer[TCPT_PERSIST],
-                   2 * tp->t_srtt, TCPTV_PERSMIN, TCPTV_MAX);
-               return;
+               break;
 
        /*
         * Keep-alive timer went off; send something
         * or drop connection if idle for too long.
         */
        case TCPT_KEEP:
 
        /*
         * Keep-alive timer went off; send something
         * or drop connection if idle for too long.
         */
        case TCPT_KEEP:
-               if (tp->t_state < TCPS_ESTABLISHED ||
-                   tp->t_idle >= TCPTV_MAXIDLE) {
-                       tcp_drop(tp, ETIMEDOUT);
-                       return;
-               }
-               if (tp->t_inpcb->inp_socket->so_options & SO_NOKEEPALIVE)
-                       tp->t_idle = 0;
-               else
+               if (tp->t_state < TCPS_ESTABLISHED)
+                       goto dropit;
+               if (tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE) {
+                       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!)
+                        */
                        tcp_respond(tp,
                        tcp_respond(tp,
-                           tp->t_template, tp->rcv_nxt, tp->snd_una-1, 0);
+                           tp->t_template, tp->rcv_nxt-1, tp->snd_una-1, 0);
+               } else
+                       tp->t_idle = 0;
                tp->t_timer[TCPT_KEEP] = TCPTV_KEEP;
                tp->t_timer[TCPT_KEEP] = TCPTV_KEEP;
-               return;
+               break;
+       dropit:
+               tp = tcp_drop(tp, ETIMEDOUT);
+               break;
        }
        }
+       return (tp);
 }
 }
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.