This is a note to let you know that I've just added the patch titled
netfilter: nf_conntrack: avoid large timeout for mid-stream pickup
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netfilter-nf_conntrack-avoid-large-timeout-for-mid-stream-pickup.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 6547a221871f139cc56328a38105d47c14874cbe Mon Sep 17 00:00:00 2001
From: Florian Westphal <[email protected]>
Date: Thu, 13 Jun 2013 17:31:28 +0200
Subject: netfilter: nf_conntrack: avoid large timeout for mid-stream pickup
From: Florian Westphal <[email protected]>
commit 6547a221871f139cc56328a38105d47c14874cbe upstream.
When loose tracking is enabled (default), non-syn packets cause
creation of new conntracks in established state with default timeout for
established state (5 days). This causes the table to fill up with UNREPLIED
when the 'new ack' packet happened to be the last-ack of a previous,
already timed-out connection.
Consider:
A 192.168.x.52792 > 10.184.y.80: F, 426:426(0) ack 9237 win 255
B 10.184.y.80 > 192.168.x.52792: ., ack 427 win 123
<61 second pause>
C 10.184.y.80 > 192.168.x.52792: F, 9237:9237(0) ack 427 win 123
D 192.168.x.52792 > 10.184.y.80: ., ack 9238 win 255
B moves conntrack to CLOSE_WAIT and will kill it after 60 second timeout,
C is ignored (FIN set), but last packet (D) causes new ct with 5-days timeout.
Use UNACK timeout (5 minutes) instead to get rid of these entries sooner
when in ESTABLISHED state without having seen traffic in both directions.
Signed-off-by: Florian Westphal <[email protected]>
Acked-by: Jozsef Kadlecsik <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>
Cc: Florian Koch <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
net/netfilter/nf_conntrack_proto_tcp.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -1043,6 +1043,12 @@ static int tcp_packet(struct nf_conn *ct
nf_ct_kill_acct(ct, ctinfo, skb);
return NF_ACCEPT;
}
+ /* ESTABLISHED without SEEN_REPLY, i.e. mid-connection
+ * pickup with loose=1. Avoid large ESTABLISHED timeout.
+ */
+ if (new_state == TCP_CONNTRACK_ESTABLISHED &&
+ timeout > timeouts[TCP_CONNTRACK_UNACK])
+ timeout = timeouts[TCP_CONNTRACK_UNACK];
} else if (!test_bit(IPS_ASSURED_BIT, &ct->status)
&& (old_state == TCP_CONNTRACK_SYN_RECV
|| old_state == TCP_CONNTRACK_ESTABLISHED)
Patches currently in stable-queue which might be from [email protected] are
queue-3.10/netfilter-nf_conntrack-avoid-large-timeout-for-mid-stream-pickup.patch
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