tipc: filter out messages not intended for this host

Port commit 20deb48d16fdd07ce2fdc8d03ea317362217e085
from git://tipc.cslab.ericsson.net/pub/git/people/allan/tipc.git

Part of the large effort I'm trying to help with getting all the downstreamed
code from windriver forward ported to the upstream tree

Origional commit message
Restore check to filter out inadverdently received messages
This patch reimplements a check that allows TIPC to discard messages
that are not intended for it.  This check was present in TIPC 1.5/1.6,
but was removed by accident during the development of TIPC 1.7; it has
now been updated to account for new features present in TIPC 1.7 and
reinserted into TIPC.  The main benefit of this check is to filter
out messages arriving from orphaned link endpoints, which can arise
when a node exits the network and then re-enters it with a different
TIPC network address (i.e. <Z.C.N> value).
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Origionally-authored-by: NAllan Stephens <allan.stephens@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/tipc/link.c

@@ -1882,6 +1882,15 @@ void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *tb_ptr)
 			     (msg_destnode(msg) != tipc_own_addr)))
 			goto cont;
 
+		/* Discard non-routeable messages destined for another node */
+
+		if (unlikely(!msg_isdata(msg) &&
+			     (msg_destnode(msg) != tipc_own_addr))) {
+			if ((msg_user(msg) != CONN_MANAGER) &&
+			    (msg_user(msg) != MSG_FRAGMENTER))
+				goto cont;
+		}
+
 		/* Locate unicast link endpoint that should handle message */
 
 		n_ptr = tipc_node_find(msg_prevnode(msg));