diff options
| author | wollman <wollman@FreeBSD.org> | 1995-10-10 17:45:43 +0000 |
|---|---|---|
| committer | wollman <wollman@FreeBSD.org> | 1995-10-10 17:45:43 +0000 |
| commit | ba18d18f326ce164eec388c53e9e209fc13bb425 (patch) | |
| tree | 76f578437142707a98880be1d42e027397bbb46c /sys/netinet/tcp_timewait.c | |
| parent | 5668a5f30b8fbc1b006b74162ab6e6d8e41ae048 (diff) | |
| download | FreeBSD-src-ba18d18f326ce164eec388c53e9e209fc13bb425.zip FreeBSD-src-ba18d18f326ce164eec388c53e9e209fc13bb425.tar.gz | |
More MTU discovery: avoid over-retransmission if route changes in the
middle of a fully-open window. Also, keep track of how many retransmits
we do as a result of MTU discovery. This may actually do more work than
necessary, but it's an unusual condition...
Suggested by: Janey Hoe <janey@lcs.mit.edu>
Diffstat (limited to 'sys/netinet/tcp_timewait.c')
| -rw-r--r-- | sys/netinet/tcp_timewait.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/sys/netinet/tcp_timewait.c b/sys/netinet/tcp_timewait.c index d166bba..0fe5d0f 100644 --- a/sys/netinet/tcp_timewait.c +++ b/sys/netinet/tcp_timewait.c @@ -31,7 +31,7 @@ * SUCH DAMAGE. * * @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95 - * $Id: tcp_subr.c,v 1.16 1995/09/22 17:43:37 wollman Exp $ + * $Id: tcp_subr.c,v 1.17 1995/10/03 16:54:15 wollman Exp $ */ #include <sys/param.h> @@ -503,6 +503,8 @@ tcp_mtudisc(inp, errno) offered = taop->tao_mssopt; mss = rt->rt_rmx.rmx_mtu - sizeof(struct tcpiphdr); mss = min(mss, offered); + if (tp->t_maxopd <= mss) + return; tp->t_maxopd = mss; if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && @@ -523,15 +525,12 @@ tcp_mtudisc(inp, errno) tp->t_maxseg = mss; - /* - * Nudge TCP output. Unfortunately, we have no way to know - * which packet that we sent is the failing one, but in the - * vast majority of cases we expect that it will be at the - * beginning of the window, so this should do the right - * thing (I hope). - */ - tp->snd_nxt = tp->snd_una; - tcp_output(tp); + if (SEQ_GT(tp->snd_una, tp->t_lastmturesend)) { + tcpstat.tcps_mturesent++; + tp->t_rtt = 0; + tp->snd_nxt = tp->t_lastmturesend = tp->snd_una; + tcp_output(tp); + } } } #endif /* MTUDISC */ |
