sctp: Make the association hashtable handle multiple network namespaces

- Use struct net in the hash calculation
- Use sock_net(association.base.sk) in the association lookups.
- On receive calculate the network namespace from skb->dev.
- Pass struct net from receive down to the functions that actually
  do the association lookup.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index ebaef3e..a3601f3 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -1089,13 +1089,15 @@
 
 /* Is this the association we are looking for? */
 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc,
+					   struct net *net,
 					   const union sctp_addr *laddr,
 					   const union sctp_addr *paddr)
 {
 	struct sctp_transport *transport;
 
 	if ((htons(asoc->base.bind_addr.port) == laddr->v4.sin_port) &&
-	    (htons(asoc->peer.port) == paddr->v4.sin_port)) {
+	    (htons(asoc->peer.port) == paddr->v4.sin_port) &&
+	    net_eq(sock_net(asoc->base.sk), net)) {
 		transport = sctp_assoc_lookup_paddr(asoc, paddr);
 		if (!transport)
 			goto out;