[NETFILTER]: Handle NAT in IPsec policy checks

Handle NAT of decapsulated IPsec packets by reconstructing the struct flowi
of the original packet from the conntrack information for IPsec policy
checks.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h
index 79bb977afeac..84506dfa1f37 100644
--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -274,6 +274,20 @@ struct nf_queue_rerouter {
 extern int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer);
 extern int nf_unregister_queue_rerouter(int pf);
 
+#include <net/flow.h>
+extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
+
+static inline void
+nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family)
+{
+#ifdef CONFIG_IP_NF_NAT_NEEDED
+        void (*decodefn)(struct sk_buff *, struct flowi *);
+
+        if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL)
+                decodefn(skb, fl);
+#endif
+}
+
 #ifdef CONFIG_PROC_FS
 #include <linux/proc_fs.h>
 extern struct proc_dir_entry *proc_net_netfilter;
@@ -282,6 +296,8 @@ extern struct proc_dir_entry *proc_net_netfilter;
 #else /* !CONFIG_NETFILTER */
 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
+static inline void
+nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {}
 #endif /*CONFIG_NETFILTER*/
 
 #endif /*__KERNEL__*/