3 files changed, 44 insertions, 6 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
index ac306d17f8ad..341ecd796aa4 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1145,7 +1145,7 @@ static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
 	default:
 		pr_warn("Dropping received illegal msg type\n");
 		kfree_skb(skb);
-		return false;
+		return true;
 	};
 }
 
@@ -1425,6 +1425,10 @@ static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
 		l->rcv_unacked = 0;
 	} else {
 		/* RESET_MSG or ACTIVATE_MSG */
+		if (mtyp == ACTIVATE_MSG) {
+			msg_set_dest_session_valid(hdr, 1);
+			msg_set_dest_session(hdr, l->peer_session);
+		}
 		msg_set_max_pkt(hdr, l->advertised_mtu);
 		strcpy(data, l->if_name);
 		msg_set_size(hdr, INT_H_SIZE + TIPC_MAX_IF_NAME);
@@ -1642,6 +1646,17 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 			break;
 		}
+
+		/* If this endpoint was re-created while peer was ESTABLISHING
+		 * it doesn't know current session number. Force re-synch.
+		 */
+		if (mtyp == ACTIVATE_MSG && msg_dest_session_valid(hdr) &&
+		    l->session != msg_dest_session(hdr)) {
+			if (less(l->session, msg_dest_session(hdr)))
+				l->session = msg_dest_session(hdr) + 1;
+			break;
+		}
+
 		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
 		if (mtyp == RESET_MSG || !link_is_up(l))
 			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
diff --git a/net/tipc/msg.h b/net/tipc/msg.h
index a0924956bb61..d7e4b8b93f9d 100644
--- a/net/tipc/msg.h
+++ b/net/tipc/msg.h
@@ -360,6 +360,28 @@ static inline void msg_set_bcast_ack(struct tipc_msg *m, u16 n)
 	msg_set_bits(m, 1, 0, 0xffff, n);
 }
 
+/* Note: reusing bits in word 1 for ACTIVATE_MSG only, to re-synch
+ * link peer session number
+ */
+static inline bool msg_dest_session_valid(struct tipc_msg *m)
+{
+	return msg_bits(m, 1, 16, 0x1);
+}
+
+static inline void msg_set_dest_session_valid(struct tipc_msg *m, bool valid)
+{
+	msg_set_bits(m, 1, 16, 0x1, valid);
+}
+
+static inline u16 msg_dest_session(struct tipc_msg *m)
+{
+	return msg_bits(m, 1, 0, 0xffff);
+}
+
+static inline void msg_set_dest_session(struct tipc_msg *m, u16 n)
+{
+	msg_set_bits(m, 1, 0, 0xffff, n);
+}
 
 /*
  * Word 2
diff --git a/net/tipc/node.c b/net/tipc/node.c
index db2a6c3e0be9..2dc4919ab23c 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -830,15 +830,16 @@ static void tipc_node_link_down(struct tipc_node *n, int bearer_id, bool delete)
 	tipc_node_write_lock(n);
 	if (!tipc_link_is_establishing(l)) {
 		__tipc_node_link_down(n, &bearer_id, &xmitq, &maddr);
-		if (delete) {
-			kfree(l);
-			le->link = NULL;
-			n->link_cnt--;
-		}
 	} else {
 		/* Defuse pending tipc_node_link_up() */
+		tipc_link_reset(l);
 		tipc_link_fsm_evt(l, LINK_RESET_EVT);
 	}
+	if (delete) {
+		kfree(l);
+		le->link = NULL;
+		n->link_cnt--;
+	}
 	trace_tipc_node_link_down(n, true, "node link down or deleted!");
 	tipc_node_write_unlock(n);
 	if (delete)