tipc: handle broadcast NAME_DISTRIBUTOR packet when receiving it

NAME_DISTRIBUTOR messages are transmitted through unicast link on TIPC
2.0, by contrast, the messages are delivered through broadcast link on
TIPC 1.7. But at present, NAME_DISTRIBUTOR messages received by
broadcast link cannot be handled in tipc_rcv() until an unicast message
arrives, which may lead to a significant delay to update name table.

To avoid this delay, we will also deal with broadcast NAME_DISTRIBUTOR
message on broadcast receive path.
Signed-off-by: Zhenbo Gao <zhenbo.gao@windriver.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/node.c

@@ -1549,6 +1549,10 @@ static void tipc_node_bc_rcv(struct net *net, struct sk_buff *skb, int bearer_id
 	if (!skb_queue_empty(&be->inputq1))
 		tipc_node_mcast_rcv(n);
 
+	/* Handle NAME_DISTRIBUTOR messages sent from 1.7 nodes */
+	if (!skb_queue_empty(&n->bc_entry.namedq))
+		tipc_named_rcv(net, &n->bc_entry.namedq);
+
 	/* If reassembly or retransmission failure => reset all links to peer */
 	if (rc & TIPC_LINK_DOWN_EVT)
 		tipc_node_reset_links(n);