Fix bug that DealerSocket has been broken after IBD.

CHANGES.md

@@ -79,8 +79,8 @@ To be released.
 
  -  Fixed a bug that `Swarm` reported `TaskCanceledException` as an unknown
     exception while stopping. [[#275]]
- -  Fixed a bug that `Swarm` didn't stop properly during `Swarm.Preload()`.
-    [[#275]]
+ -  Fixed a bug that `Swarm` didn't stop properly during
+    `Swarm.PreloadAsync()`. [[#275]]
  -  Fixed a bug where the oldest `TxNonce` of an address is not invalidated
     when forking using `FileStore.ForkTxNonce()` method.  [[#281]]
  -  Fixed a bug where `LiteDBStore.GetTxNonce()` method throws a
@@ -91,6 +91,8 @@ To be released.
  -  Fixed a bug that `KeyNotFoundException` had been thrown instead of
     `ArgumentOutOfRangeException` when `Blockchain<T>[int]` called while the
     index of a block that does not exist locally.  [[#208], [#317]]
+ -  Fixed a bug that `Swarm` had not dial to other peer after
+    `Swarm.PreloadAsync()`.  [[#311]]
 
 
 [LiteDB]: https://www.litedb.org/
@@ -116,6 +118,7 @@ To be released.
 [#308]: https://github.com/planetarium/libplanet/pull/308
 [#309]: https://github.com/planetarium/libplanet/issues/309
 [#310]: https://github.com/planetarium/libplanet/pull/310
+[#311]: https://github.com/planetarium/libplanet/pull/311
 [#317]: https://github.com/planetarium/libplanet/pull/317
 
 

Libplanet/Net/Swarm.cs

@@ -132,6 +132,7 @@ public Swarm(
 
             _dealers = new ConcurrentDictionary<Address, DealerSocket>();
             _router = new RouterSocket();
+            _router.Options.RouterHandover = true;
             _replyQueue = new NetMQQueue<Message>();
             _broadcastQueue = new NetMQQueue<Message>();
             _queuePoller = new NetMQPoller { _replyQueue, _broadcastQueue };
@@ -1717,11 +1718,16 @@ private async Task<Pong> DialPeerAsync(
                 await CreatePermission(peer);
             }
 
-            if (!_dealers.TryGetValue(peer.Address, out DealerSocket dealer))
+            // We create a new DealerSocket for each DialPeerAsync()
+            // because NetMQ doesn't handle properly previosuly connected sockets.
+            if (_dealers.TryGetValue(peer.Address, out DealerSocket dealer))
             {
-                dealer = new DealerSocket();
+                dealer.Dispose();
             }
 
+            dealer = new DealerSocket();
+            dealer.Options.Identity = Address.ToByteArray();
+
             try
             {
                 _logger.Debug($"Trying to DialAsync({peer.EndPoint})...");