tipc: fix bug in bundled buffer reception

In commit ec8a2e5621db2da24badb3969eda7fd359e1869f ("tipc: same receive
code path for connection protocol and data messages") we omitted the
the possiblilty that an arriving message extracted from a bundle buffer
may be a multicast message. Such messages need to be to be delivered to
the socket via a separate function, tipc_sk_mcast_rcv(). As a result,
small multicast messages arriving as members of a bundle buffer will be
silently dropped.

This commit corrects the error by considering this case in the function
tipc_link_bundle_rcv().

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/link.c

@@ -1924,7 +1924,12 @@ void tipc_link_bundle_rcv(struct sk_buff *buf)
 		}
 		omsg = buf_msg(obuf);
 		pos += align(msg_size(omsg));
-		if (msg_isdata(omsg) || (msg_user(omsg) == CONN_MANAGER)) {
+		if (msg_isdata(omsg)) {
+			if (unlikely(msg_type(omsg) == TIPC_MCAST_MSG))
+				tipc_sk_mcast_rcv(obuf);
+			else
+				tipc_sk_rcv(obuf);
+		} else if (msg_user(omsg) == CONN_MANAGER) {
 			tipc_sk_rcv(obuf);
 		} else if (msg_user(omsg) == NAME_DISTRIBUTOR) {
 			tipc_named_rcv(obuf);