[PATCH] Fix RST handling in ip_conntrack_proto_tcp.c
gandalf at wlug.westbo.se
Fri Dec 31 17:38:56 CET 2004
Your latest patch contained a change to the RST handling.
The change was that an RST is ignored if the previous packet was an ACK.
This is happens all the time. I know it was intended as a fix for the
SYN - ACK probe - RST sequence but it breaks normal usage. The problem
is that connections that end with RST never get their state changed and
are left in ESTABLISHED state with a large timeout.
The patch below adds a check for
!test_bit(IPS_ASSURED_BIT, &conntrack->status) so your change will only
be active for unassured connections. Maybe you have a better idea for
how to fix both cases.
This patch has been tested by a user that reported the problem on irc
and it fixes the problem for him. I'm also running it on a machine with
lots of traffic and it fixes the problem for me as well.
Please make sure something that fixes the problem is submitted fairly
<hint> A tcp-state/windowtracking testcase for nfsim would be great
--- linux-2.6.10-rc3-bk14/net/ipv4/netfilter/ip_conntrack_proto_tcp.c.orig 2004-12-30 19:48:33.000000000 +0100
+++ linux-2.6.10-rc3-bk14/net/ipv4/netfilter/ip_conntrack_proto_tcp.c 2004-12-30 19:49:46.000000000 +0100
@@ -906,7 +906,8 @@ static int tcp_packet(struct ip_conntrac
if (index == TCP_RST_SET
&& ((test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)
&& conntrack->proto.tcp.last_index <= TCP_SYNACK_SET)
- || conntrack->proto.tcp.last_index == TCP_ACK_SET)
+ || (!test_bit(IPS_ASSURED_BIT, &conntrack->status)
+ && conntrack->proto.tcp.last_index == TCP_ACK_SET))
/* Ignore RST closing down invalid SYN or ACK
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