3 files changed, 45 insertions, 4 deletions

diff --git a/include/linux/netfilter_ipv4.h b/include/linux/netfilter_ipv4.h
index fdc4a9527343..43c09d790b83 100644
--- a/include/linux/netfilter_ipv4.h
+++ b/include/linux/netfilter_ipv4.h
@@ -79,7 +79,7 @@ enum nf_ip_hook_priorities {
 
 #ifdef __KERNEL__
 extern int ip_route_me_harder(struct sk_buff **pskb);
-
+extern int ip_xfrm_me_harder(struct sk_buff **pskb);
 #endif /*__KERNEL__*/
 
 #endif /*__LINUX_IP_NETFILTER_H*/
diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
index 52a3d7c57907..ed42cdc57cd9 100644
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -78,6 +78,47 @@ int ip_route_me_harder(struct sk_buff **pskb)
 }
 EXPORT_SYMBOL(ip_route_me_harder);
 
+#ifdef CONFIG_XFRM
+int ip_xfrm_me_harder(struct sk_buff **pskb)
+{
+        struct flowi fl;
+        unsigned int hh_len;
+        struct dst_entry *dst;
+
+        if (IPCB(*pskb)->flags & IPSKB_XFRM_TRANSFORMED)
+                return 0;
+        if (xfrm_decode_session(*pskb, &fl, AF_INET) < 0)
+                return -1;
+
+        dst = (*pskb)->dst;
+        if (dst->xfrm)
+                dst = ((struct xfrm_dst *)dst)->route;
+        dst_hold(dst);
+
+        if (xfrm_lookup(&dst, &fl, (*pskb)->sk, 0) < 0)
+                return -1;
+
+        dst_release((*pskb)->dst);
+        (*pskb)->dst = dst;
+
+        /* Change in oif may mean change in hh_len. */
+        hh_len = (*pskb)->dst->dev->hard_header_len;
+        if (skb_headroom(*pskb) < hh_len) {
+                struct sk_buff *nskb;
+
+                nskb = skb_realloc_headroom(*pskb, hh_len);
+                if (!nskb)
+                        return -1;
+                if ((*pskb)->sk)
+                        skb_set_owner_w(nskb, (*pskb)->sk);
+                kfree_skb(*pskb);
+                *pskb = nskb;
+        }
+        return 0;
+}
+EXPORT_SYMBOL(ip_xfrm_me_harder);
+#endif
+
 void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
 EXPORT_SYMBOL(ip_nat_decode_session);
 
diff --git a/net/ipv4/netfilter/ip_nat_standalone.c b/net/ipv4/netfilter/ip_nat_standalone.c
index 92c54999a19d..7c3f7d380240 100644
--- a/net/ipv4/netfilter/ip_nat_standalone.c
+++ b/net/ipv4/netfilter/ip_nat_standalone.c
@@ -235,19 +235,19 @@ ip_nat_out(unsigned int hooknum,
                 return NF_ACCEPT;
 
         ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
+#ifdef CONFIG_XFRM
         if (ret != NF_DROP && ret != NF_STOLEN
             && (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
-#ifdef CONFIG_XFRM
                     || ct->tuplehash[dir].tuple.src.u.all !=
                        ct->tuplehash[!dir].tuple.dst.u.all
-#endif
                     )
-                        return ip_route_me_harder(pskb) == 0 ? ret : NF_DROP;
+                        return ip_xfrm_me_harder(pskb) == 0 ? ret : NF_DROP;
         }
+#endif
         return ret;
 }