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authorfriehm <friehm@cvs.openbsd.org>2018-09-17 14:07:49 +0000
committerfriehm <friehm@cvs.openbsd.org>2018-09-17 14:07:49 +0000
commitb8fa2c65c5b53e6be3413c67b27d7dd32834e8aa (patch)
tree481af08caa757427f3f0cb099f159bf5a6a65b12 /sys/netinet/tcp_input.c
parentae66c8fad14a8c9f7cdf0c0e32bfb6819264a9db (diff)
Do not acknowledge a received ack-only tcp packet that we would drop due to
PAWS. Otherwise we could trigger a retransmit of the opposite party with another wrong timestamp and produce loop. I have seen this with a buggy server which messed up tcp timestamps. Suggested by Prof. Jacobson for FreeBSD. ok krw, bluhm, henning, mpi
Diffstat (limited to 'sys/netinet/tcp_input.c')
-rw-r--r--sys/netinet/tcp_input.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index 899471dbbcc..0244e2907ab 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tcp_input.c,v 1.358 2018/07/23 21:14:00 bluhm Exp $ */
+/* $OpenBSD: tcp_input.c,v 1.359 2018/09/17 14:07:48 friehm Exp $ */
/* $NetBSD: tcp_input.c,v 1.23 1996/02/13 23:43:44 christos Exp $ */
/*
@@ -1270,7 +1270,9 @@ trimthenstep6:
} else {
tcpstat_pkt(tcps_rcvduppack, tcps_rcvdupbyte, tlen);
tcpstat_inc(tcps_pawsdrop);
- goto dropafterack;
+ if (tlen)
+ goto dropafterack;
+ goto drop;
}
}