tipc: Don't respond to neighbor discovery request on blocked bearer

Adds a check to prevent TIPC from trying to respond to an incoming
LINK_CONFIG request message if the associated bearer is currently
prohibited from sending messages.

Signed-off-by: Allan Stephens <Allan.Stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

net/tipc/discover.c

@@ -202,7 +202,7 @@ void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr)
 	/* Accept discovery message & send response, if necessary */
 	link_fully_up = link_working_working(link);
 
-	if ((type == DSC_REQ_MSG) && !link_fully_up) {
+	if ((type == DSC_REQ_MSG) && !link_fully_up && !b_ptr->blocked) {
 		rbuf = tipc_disc_init_msg(DSC_RESP_MSG, orig, b_ptr);
 		if (rbuf) {
 			b_ptr->media->send_msg(rbuf, b_ptr, &media_addr);