Merge branch 'tipc-dad-fixes'

Jon Maloy says:

====================
tipc: fixes in duplicate address discovery function

commit 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address
hash values") introduced new functionality that has turned out to
contain several bugs and weaknesses.

We address those in this series.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/discover.c

@@ -133,6 +133,8 @@ static void disc_dupl_alert(struct tipc_bearer *b, u32 node_addr,
 }
 
 /* tipc_disc_addr_trial(): - handle an address uniqueness trial from peer
+ * Returns true if message should be dropped by caller, i.e., if it is a
+ * trial message or we are inside trial period. Otherwise false.
  */
 static bool tipc_disc_addr_trial_msg(struct tipc_discoverer *d,
 				     struct tipc_media_addr *maddr,
@@ -168,8 +170,9 @@ static bool tipc_disc_addr_trial_msg(struct tipc_discoverer *d,
 		msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
 	}
 
+	/* Accept regular link requests/responses only after trial period */
 	if (mtyp != DSC_TRIAL_MSG)
-		return false;
+		return trial;
 
 	sugg_addr = tipc_node_try_addr(net, peer_id, src);
 	if (sugg_addr)
@@ -284,7 +287,6 @@ static void tipc_disc_timeout(struct timer_list *t)
 {
 	struct tipc_discoverer *d = from_timer(d, t, timer);
 	struct tipc_net *tn = tipc_net(d->net);
-	u32 self = tipc_own_addr(d->net);
 	struct tipc_media_addr maddr;
 	struct sk_buff *skb = NULL;
 	struct net *net = d->net;
@@ -298,12 +300,14 @@ static void tipc_disc_timeout(struct timer_list *t)
 		goto exit;
 	}
 
-	/* Did we just leave the address trial period ? */
-	if (!self && !time_before(jiffies, tn->addr_trial_end)) {
-		self = tn->trial_addr;
-		tipc_net_finalize(net, self);
-		msg_set_prevnode(buf_msg(d->skb), self);
+	/* Trial period over ? */
+	if (!time_before(jiffies, tn->addr_trial_end)) {
+		/* Did we just leave it ? */
+		if (!tipc_own_addr(net))
+			tipc_net_finalize(net, tn->trial_addr);
+
 		msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
+		msg_set_prevnode(buf_msg(d->skb), tipc_own_addr(net));
 	}
 
 	/* Adjust timeout interval according to discovery phase */

net/tipc/net.c

@@ -121,12 +121,17 @@ int tipc_net_init(struct net *net, u8 *node_id, u32 addr)
 
 void tipc_net_finalize(struct net *net, u32 addr)
 {
-	tipc_set_node_addr(net, addr);
-	smp_mb();
-	tipc_named_reinit(net);
-	tipc_sk_reinit(net);
-	tipc_nametbl_publish(net, TIPC_CFG_SRV, addr, addr,
-			     TIPC_CLUSTER_SCOPE, 0, addr);
+	struct tipc_net *tn = tipc_net(net);
+
+	spin_lock_bh(&tn->node_list_lock);
+	if (!tipc_own_addr(net)) {
+		tipc_set_node_addr(net, addr);
+		tipc_named_reinit(net);
+		tipc_sk_reinit(net);
+		tipc_nametbl_publish(net, TIPC_CFG_SRV, addr, addr,
+				     TIPC_CLUSTER_SCOPE, 0, addr);
+	}
+	spin_unlock_bh(&tn->node_list_lock);
 }
 
 void tipc_net_stop(struct net *net)

net/tipc/node.c

@@ -797,6 +797,7 @@ static u32 tipc_node_suggest_addr(struct net *net, u32 addr)
 }
 
 /* tipc_node_try_addr(): Check if addr can be used by peer, suggest other if not
+ * Returns suggested address if any, otherwise 0
  */
 u32 tipc_node_try_addr(struct net *net, u8 *id, u32 addr)
 {
@@ -819,12 +820,14 @@ u32 tipc_node_try_addr(struct net *net, u8 *id, u32 addr)
 	if (n) {
 		addr = n->addr;
 		tipc_node_put(n);
+		return addr;
 	}
-	/* Even this node may be in trial phase */
+
+	/* Even this node may be in conflict */
 	if (tn->trial_addr == addr)
 		return tipc_node_suggest_addr(net, addr);
 
-	return addr;
+	return 0;
 }
 
 void tipc_node_check_dest(struct net *net, u32 addr,