tipc: Prevent missing name table entries when link flip-flops rapidly

Ensure that TIPC does not re-establish communication with a
neighboring node until it has finished updating all data structures
containing information about that node to reflect the earlier loss of
contact.  Previously, it was possible for TIPC to perform its purge of
name table entries relating to the node once contact had already been
re-established, resulting in the unwanted removal of valid name table
entries.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 1 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 9d18c9b7638..a6a3102bb4d 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1869,13 +1869,22 @@ void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *tb_ptr)
 				goto cont;
 		}
 
-		/* Locate unicast link endpoint that should handle message */
+		/* Locate neighboring node that sent message */
 
 		n_ptr = tipc_node_find(msg_prevnode(msg));
 		if (unlikely(!n_ptr))
 			goto cont;
 		tipc_node_lock(n_ptr);
 
+		/* Don't talk to neighbor during cleanup after last session */
+
+		if (n_ptr->cleanup_required) {
+			tipc_node_unlock(n_ptr);
+			goto cont;
+		}
+
+		/* Locate unicast link endpoint that should handle message */
+
 		l_ptr = n_ptr->links[b_ptr->identity];
 		if (unlikely(!l_ptr)) {
 			tipc_node_unlock(n_ptr);