netfilter: nf_conntrack: Add a struct net parameter to l4_pkt_to_tuple

As gre does not have the srckey in the packet gre_pkt_to_tuple
needs to perform a lookup in it's per network namespace tables.

Pass in the proper network namespace to all pkt_to_tuple
implementations to ensure gre (and any similar protocols) can get this
right.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nf_conntrack_proto_udp.c b/net/netfilter/nf_conntrack_proto_udp.c
index 6957281..478f92f 100644
--- a/net/netfilter/nf_conntrack_proto_udp.c
+++ b/net/netfilter/nf_conntrack_proto_udp.c
@@ -38,6 +38,7 @@
 
 static bool udp_pkt_to_tuple(const struct sk_buff *skb,
 			     unsigned int dataoff,
+			     struct net *net,
 			     struct nf_conntrack_tuple *tuple)
 {
 	const struct udphdr *hp;