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authorJulian Anastasov <ja@ssi.bg>2011-06-16 17:29:22 +0200
committerPatrick McHardy <kaber@trash.net>2011-06-16 17:29:22 +0200
commit42c1edd345c8412d96e7a362ee06feb7be73bb6c (patch)
tree5b05b0324b8186fe8bc40ffced48c856b099547d /include/net
parent2c38de4c1f8da799bdca0e4bb40ca13f2174d3e8 (diff)
netfilter: nf_nat: avoid double seq_adjust for loopback
Avoid double seq adjustment for loopback traffic because it causes silent repetition of TCP data. One example is passive FTP with DNAT rule and difference in the length of IP addresses. This patch adds check if packet is sent and received via loopback device. As the same conntrack is used both for outgoing and incoming direction, we restrict seq adjustment to happen only in POSTROUTING. Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Patrick McHardy <kaber@trash.net>
Diffstat (limited to 'include/net')
-rw-r--r--include/net/netfilter/nf_conntrack.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index c7c42e7acc31..5d4f8e586e32 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -307,6 +307,12 @@ static inline int nf_ct_is_untracked(const struct nf_conn *ct)
return test_bit(IPS_UNTRACKED_BIT, &ct->status);
}
+/* Packet is received from loopback */
+static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
+{
+ return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
+}
+
extern int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
extern unsigned int nf_conntrack_htable_size;
extern unsigned int nf_conntrack_max;