tipc: fix bug in broadcast synch message create function

In commit d999297c3dbbe7fdd832f7fa4ec84301e170b3e6
("tipc: reduce locking scope during packet reception") we introduced
a new function tipc_build_bcast_sync_msg(), which carries initial
synchronization data between two nodes at first contact and at
re-contact. In this function, we missed to add synchronization data,
with the effect that the broadcast link endpoints will fail to
synchronize correctly at re-contact between a running and a restarted
node. All other cases work as intended.

With this commit, we fix this bug.

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

net/tipc/link.c

@@ -294,11 +294,14 @@ static void tipc_link_build_bcast_sync_msg(struct tipc_link *l,
 {
 	struct sk_buff *skb;
 	struct sk_buff_head list;
+	u16 last_sent;
 
 	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
 			      0, l->addr, link_own_addr(l), 0, 0, 0);
 	if (!skb)
 		return;
+	last_sent = tipc_bclink_get_last_sent(l->owner->net);
+	msg_set_last_bcast(buf_msg(skb), last_sent);
 	__skb_queue_head_init(&list);
 	__skb_queue_tail(&list, skb);
 	tipc_link_xmit(l, &list, xmitq);