[NETFILTER]: Use conntrack information to determine if packet was NATed
Preparation for IPsec support for NAT:
Use conntrack information instead of saving the saving and comparing the
addresses to determine if a packet was NATed and needs to be rerouted to
make it easier to extend the key.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/ip_nat_standalone.c b/net/ipv4/netfilter/ip_nat_standalone.c
index f04111f7..1bb5089 100644
--- a/net/ipv4/netfilter/ip_nat_standalone.c
+++ b/net/ipv4/netfilter/ip_nat_standalone.c
@@ -162,18 +162,20 @@
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
- u_int32_t saddr, daddr;
+ struct ip_conntrack *ct;
+ enum ip_conntrack_info ctinfo;
unsigned int ret;
- saddr = (*pskb)->nh.iph->saddr;
- daddr = (*pskb)->nh.iph->daddr;
-
ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
if (ret != NF_DROP && ret != NF_STOLEN
- && ((*pskb)->nh.iph->saddr != saddr
- || (*pskb)->nh.iph->daddr != daddr)) {
- dst_release((*pskb)->dst);
- (*pskb)->dst = NULL;
+ && (ct = ip_conntrack_get(*pskb, &ctinfo)) != NULL) {
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+
+ if (ct->tuplehash[dir].tuple.src.ip !=
+ ct->tuplehash[!dir].tuple.dst.ip) {
+ dst_release((*pskb)->dst);
+ (*pskb)->dst = NULL;
+ }
}
return ret;
}
@@ -200,7 +202,8 @@
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
- u_int32_t saddr, daddr;
+ struct ip_conntrack *ct;
+ enum ip_conntrack_info ctinfo;
unsigned int ret;
/* root is playing with raw sockets. */
@@ -208,14 +211,15 @@
|| (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr))
return NF_ACCEPT;
- saddr = (*pskb)->nh.iph->saddr;
- daddr = (*pskb)->nh.iph->daddr;
-
ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
if (ret != NF_DROP && ret != NF_STOLEN
- && ((*pskb)->nh.iph->saddr != saddr
- || (*pskb)->nh.iph->daddr != daddr))
- return ip_route_me_harder(pskb) == 0 ? ret : NF_DROP;
+ && (ct = ip_conntrack_get(*pskb, &ctinfo)) != NULL) {
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+
+ if (ct->tuplehash[dir].tuple.dst.ip !=
+ ct->tuplehash[!dir].tuple.src.ip)
+ return ip_route_me_harder(pskb) == 0 ? ret : NF_DROP;
+ }
return ret;
}