Author: andre
Date: Fri Jul 5 14:24:37 2013
New Revision: 252786
URL: http://svnweb.freebsd.org/changeset/base/252786
Log:
MFC r249809:
When doing RFC3042 limited transmit on the first on second
duplicate ACK make sure we actually have new data to send.
This prevents us from sending unneccessary pure ACKs.
Reported by: Matt Miller <m...@matthewjmiller.net>
Modified:
stable/9/sys/netinet/tcp_input.c
Directory Properties:
stable/9/sys/ (props changed)
Modified: stable/9/sys/netinet/tcp_input.c
==============================================================================
--- stable/9/sys/netinet/tcp_input.c Fri Jul 5 14:18:09 2013
(r252785)
+++ stable/9/sys/netinet/tcp_input.c Fri Jul 5 14:24:37 2013
(r252786)
@@ -2532,6 +2532,7 @@ tcp_do_segment(struct mbuf *m, struct tc
u_long oldcwnd = tp->snd_cwnd;
tcp_seq oldsndmax = tp->snd_max;
u_int sent;
+ int avail;
KASSERT(tp->t_dupacks == 1 ||
tp->t_dupacks == 2,
@@ -2553,7 +2554,17 @@ tcp_do_segment(struct mbuf *m, struct tc
*/
break;
}
- (void) tcp_output(tp);
+ /*
+ * Only call tcp_output when there
+ * is new data available to be sent.
+ * Otherwise we would send pure ACKs.
+ */
+ SOCKBUF_LOCK(&so->so_snd);
+ avail = so->so_snd.sb_cc -
+ (tp->snd_nxt - tp->snd_una);
+ SOCKBUF_UNLOCK(&so->so_snd);
+ if (avail > 0)
+ (void) tcp_output(tp);
sent = tp->snd_max - oldsndmax;
if (sent > tp->t_maxseg) {
KASSERT((tp->t_dupacks == 2 &&
_______________________________________________
svn-src-all@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
