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netfilter: xt_connlimit: pick right dstaddr in NAT scenario

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xt_connlimit normally records the "original" tuples in a hashlist
(such as "1.2.3.4 -> 5.6.7.8"), and looks in this list for iph->daddr
when counting.

When the user however uses DNAT in PREROUTING, looking for
iph->daddr -- which is now 192.168.9.10 -- will not match. Thus in
daddr mode, we need to record the reverse direction tuple
("192.168.9.10 -> 1.2.3.4") instead. In the reverse tuple, the dst
addr is on the src side, which is convenient, as count_them still uses
&conn->tuple.src.u3.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
This commit is contained in:
Jan Engelhardt 2011-01-26 11:50:03 +01:00
parent 4b3fd57138
commit ad86e1f27a
1 changed files with 8 additions and 4 deletions
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12
net/netfilter/xt_connlimit.c
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@ -185,11 +185,15 @@ connlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
int connections;
ct = nf_ct_get(skb, &ctinfo);
if (ct != NULL)
tuple_ptr = &ct->tuplehash[0].tuple;
else if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
par->family, &tuple))
if (ct != NULL) {
if (info->flags & XT_CONNLIMIT_DADDR)
tuple_ptr = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
else
tuple_ptr = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
} else if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
par->family, &tuple)) {
goto hotdrop;
}
if (par->family == NFPROTO_IPV6) {
const struct ipv6hdr *iph = ipv6_hdr(skb);