Keep track of the number of samples through the srtt filter so that we

know better when to cache values in the route, rather than relying on a
heuristic involving sequence numbers that broke when tcp_sendspace
was increased to 16k.

5 files changed, 23 insertions, 21 deletions

diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index bf0fd0c..eb459c2 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	From: @(#)tcp_input.c	8.5 (Berkeley) 4/10/94
- *	$Id: tcp_input.c,v 1.24 1995/05/11 01:41:06 davidg Exp $
+ *	$Id: tcp_input.c,v 1.25 1995/05/30 08:09:55 rgrimes Exp $
  */
 
 #ifndef TUBA_INCLUDE
@@ -1814,6 +1814,7 @@ tcp_xmit_timer(tp, rtt)
 	register short delta;
 
 	tcpstat.tcps_rttupdated++;
+	tp->t_rttupdated++;
 	if (tp->t_srtt != 0) {
 		/*
 		 * srtt is stored as fixed point with 3 bits after the
diff --git a/sys/netinet/tcp_reass.c b/sys/netinet/tcp_reass.c
index bf0fd0c..eb459c2 100644
--- a/sys/netinet/tcp_reass.c
+++ b/sys/netinet/tcp_reass.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	From: @(#)tcp_input.c	8.5 (Berkeley) 4/10/94
- *	$Id: tcp_input.c,v 1.24 1995/05/11 01:41:06 davidg Exp $
+ *	$Id: tcp_input.c,v 1.25 1995/05/30 08:09:55 rgrimes Exp $
  */
 
 #ifndef TUBA_INCLUDE
@@ -1814,6 +1814,7 @@ tcp_xmit_timer(tp, rtt)
 	register short delta;
 
 	tcpstat.tcps_rttupdated++;
+	tp->t_rttupdated++;
 	if (tp->t_srtt != 0) {
 		/*
 		 * srtt is stored as fixed point with 3 bits after the
diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
index b2f96a2..cf0fc40 100644
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)tcp_subr.c	8.1 (Berkeley) 6/10/93
- * $Id: tcp_subr.c,v 1.11 1995/05/30 08:09:58 rgrimes Exp $
+ * $Id: tcp_subr.c,v 1.12 1995/06/19 16:45:33 wollman Exp $
  */
 
 #include <sys/param.h>
@@ -303,18 +303,17 @@ tcp_close(tp)
 	register struct rtentry *rt;
 
 	/*
-	 * If we sent enough data to get some meaningful characteristics,
-	 * save them in the routing entry.  'Enough' is arbitrarily
-	 * defined as the sendpipesize (default 4K) * 16.  This would
-	 * give us 16 rtt samples assuming we only get one sample per
-	 * window (the usual case on a long haul net).  16 samples is
-	 * enough for the srtt filter to converge to within 5% of the correct
-	 * value; fewer samples and we could save a very bogus rtt.
+	 * If we got enough samples through the srtt filter,
+	 * save the rtt and rttvar in the routing entry.
+	 * 'Enough' is arbitrarily defined as the 16 samples.
+	 * 16 samples is enough for the srtt filter to converge
+	 * to within 5% of the correct value; fewer samples and
+	 * we could save a very bogus rtt.
 	 *
 	 * Don't update the default route's characteristics and don't
 	 * update anything that the user "locked".
 	 */
-	if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) &&
+	if (tp->t_rttupdated >= 16 &&
 	    (rt = inp->inp_route.ro_rt) &&
 	    ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr != INADDR_ANY) {
 		register u_long i = 0;
diff --git a/sys/netinet/tcp_timewait.c b/sys/netinet/tcp_timewait.c
index b2f96a2..cf0fc40 100644
--- a/sys/netinet/tcp_timewait.c
+++ b/sys/netinet/tcp_timewait.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)tcp_subr.c	8.1 (Berkeley) 6/10/93
- * $Id: tcp_subr.c,v 1.11 1995/05/30 08:09:58 rgrimes Exp $
+ * $Id: tcp_subr.c,v 1.12 1995/06/19 16:45:33 wollman Exp $
  */
 
 #include <sys/param.h>
@@ -303,18 +303,17 @@ tcp_close(tp)
 	register struct rtentry *rt;
 
 	/*
-	 * If we sent enough data to get some meaningful characteristics,
-	 * save them in the routing entry.  'Enough' is arbitrarily
-	 * defined as the sendpipesize (default 4K) * 16.  This would
-	 * give us 16 rtt samples assuming we only get one sample per
-	 * window (the usual case on a long haul net).  16 samples is
-	 * enough for the srtt filter to converge to within 5% of the correct
-	 * value; fewer samples and we could save a very bogus rtt.
+	 * If we got enough samples through the srtt filter,
+	 * save the rtt and rttvar in the routing entry.
+	 * 'Enough' is arbitrarily defined as the 16 samples.
+	 * 16 samples is enough for the srtt filter to converge
+	 * to within 5% of the correct value; fewer samples and
+	 * we could save a very bogus rtt.
 	 *
 	 * Don't update the default route's characteristics and don't
 	 * update anything that the user "locked".
 	 */
-	if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) &&
+	if (tp->t_rttupdated >= 16 &&
 	    (rt = inp->inp_route.ro_rt) &&
 	    ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr != INADDR_ANY) {
 		register u_long i = 0;
diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
index c5f35d3..8a9c621 100644
--- a/sys/netinet/tcp_var.h
+++ b/sys/netinet/tcp_var.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)tcp_var.h	8.3 (Berkeley) 4/10/94
- * $Id: tcp_var.h,v 1.11 1995/04/09 01:29:29 davidg Exp $
+ * $Id: tcp_var.h,v 1.12 1995/06/19 16:45:33 wollman Exp $
  */
 
 #ifndef _NETINET_TCP_VAR_H_
@@ -139,6 +139,8 @@ struct tcpcb {
 
 /* TUBA stuff */
 	caddr_t	t_tuba_pcb;		/* next level down pcb for TCP over z */
+/* More RTT stuff */
+	u_long	t_rttupdated;		/* number of times rtt sampled */
 };
 
 /*