sctp: Make the port hash table use struct net in it's key.

- Add struct net into the port hash table hash calculation
- Add struct net inot the struct sctp_bind_bucket so there
  is a memory of which network namespace a port is allocated in.
  No need for a ref count because sctp_bind_bucket only exists
  when there are sockets in the hash table and sockets can not
  change their network namspace, and sockets already ref count
  their network namespace.
- Add struct net into the key comparison when we are testing
  to see if we have found the port hash table entry we are
  looking for.

With these changes lookups in the port hash table becomes
safe to use in multiple network namespaces.

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>

2 files changed, 3 insertions, 2 deletions

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index ff499640528b..7c0504034583 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -632,9 +632,9 @@ static inline int sctp_sanity_check(void)
 
 /* Warning: The following hash functions assume a power of two 'size'. */
 /* This is the hash function for the SCTP port hash table. */
-static inline int sctp_phashfn(__u16 lport)
+static inline int sctp_phashfn(struct net *net, __u16 lport)
 {
-        return lport & (sctp_port_hashsize - 1);
+        return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
 }
 
 /* This is the hash function for the endpoint hash table. */
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index fc5e60016e37..c089bb12af77 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -102,6 +102,7 @@ struct sctp_bind_bucket {
         unsigned short  fastreuse;
         struct hlist_node       node;
         struct hlist_head       owner;
+        struct net      *net;
 };
 
 struct sctp_bind_hashbucket {