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| author | Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> | 2009-11-06 00:43:42 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-11-06 00:43:42 -0800 |
| commit | f9dd09c7f7199685601d75882447a6598be8a3e0 (patch) | |
| tree | 98ab4a75ec6c74cdb4aa807c491002ba33de56c5 /include/net | |
| parent | f5209b4446d185cc95f46363f8043a743530c15a (diff) | |
| download | linux-f9dd09c7f7199685601d75882447a6598be8a3e0.tar.gz linux-f9dd09c7f7199685601d75882447a6598be8a3e0.tar.bz2 linux-f9dd09c7f7199685601d75882447a6598be8a3e0.zip | |
netfilter: nf_nat: fix NAT issue in 2.6.30.4+
Vitezslav Samel discovered that since 2.6.30.4+ active FTP can not work
over NAT. The "cause" of the problem was a fix of unacknowledged data
detection with NAT (commit a3a9f79e361e864f0e9d75ebe2a0cb43d17c4272).
However, actually, that fix uncovered a long standing bug in TCP conntrack:
when NAT was enabled, we simply updated the max of the right edge of
the segments we have seen (td_end), by the offset NAT produced with
changing IP/port in the data. However, we did not update the other parameter
(td_maxend) which is affected by the NAT offset. Thus that could drift
away from the correct value and thus resulted breaking active FTP.
The patch below fixes the issue by *not* updating the conntrack parameters
from NAT, but instead taking into account the NAT offsets in conntrack in a
consistent way. (Updating from NAT would be more harder and expensive because
it'd need to re-calculate parameters we already calculated in conntrack.)
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/netfilter/nf_conntrack.h | 8 | ||||
| -rw-r--r-- | include/net/netfilter/nf_nat_helper.h | 4 |
2 files changed, 7 insertions, 5 deletions
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h index cbdd6284996d..5cf7270e3ffc 100644 --- a/include/net/netfilter/nf_conntrack.h +++ b/include/net/netfilter/nf_conntrack.h @@ -255,11 +255,9 @@ static inline bool nf_ct_kill(struct nf_conn *ct) } /* These are for NAT. Icky. */ -/* Update TCP window tracking data when NAT mangles the packet */ -extern void nf_conntrack_tcp_update(const struct sk_buff *skb, - unsigned int dataoff, - struct nf_conn *ct, int dir, - s16 offset); +extern s16 (*nf_ct_nat_offset)(const struct nf_conn *ct, + enum ip_conntrack_dir dir, + u32 seq); /* Fake conntrack entry for untracked connections */ extern struct nf_conn nf_conntrack_untracked; diff --git a/include/net/netfilter/nf_nat_helper.h b/include/net/netfilter/nf_nat_helper.h index 237a961f40e1..4222220920a5 100644 --- a/include/net/netfilter/nf_nat_helper.h +++ b/include/net/netfilter/nf_nat_helper.h @@ -32,4 +32,8 @@ extern int (*nf_nat_seq_adjust_hook)(struct sk_buff *skb, * to port ct->master->saved_proto. */ extern void nf_nat_follow_master(struct nf_conn *ct, struct nf_conntrack_expect *this); + +extern s16 nf_nat_get_offset(const struct nf_conn *ct, + enum ip_conntrack_dir dir, + u32 seq); #endif |