Merge from develop.

Source/MQTTnet/Adapter/MqttChannelAdapter.cs

@@ -154,6 +154,9 @@ namespace MQTTnet.Adapter
 
                 return packet;
             }
+            catch (OperationCanceledException)
+            {
+            }
             catch (Exception exception)
             {
                 if (IsWrappedException(exception))
@@ -241,7 +244,8 @@ namespace MQTTnet.Adapter
         {
             if (exception is IOException && exception.InnerException is SocketException socketException)
             {
-                if (socketException.SocketErrorCode == SocketError.ConnectionAborted)
+                if (socketException.SocketErrorCode == SocketError.ConnectionAborted ||
+                    socketException.SocketErrorCode == SocketError.OperationAborted)
                 {
                     throw new OperationCanceledException();
                 }

Source/MQTTnet/Client/IMqttClientFactory.cs

@@ -7,5 +7,9 @@ namespace MQTTnet.Client
         IMqttClient CreateMqttClient();
 
         IMqttClient CreateMqttClient(IMqttNetLogger logger);
+
+        IMqttClient CreateMqttClient(IMqttClientAdapterFactory adapterFactory);
+
+        IMqttClient CreateMqttClient(IMqttNetLogger logger, IMqttClientAdapterFactory adapterFactory);
     }
 }

Source/MQTTnet/Client/MqttClient.cs

@@ -30,7 +30,7 @@ namespace MQTTnet.Client
         internal Task _keepAliveMessageSenderTask;
         private IMqttChannelAdapter _adapter;
         private bool _cleanDisconnectInitiated;
-        private TaskCompletionSource<bool> _disconnectReason;
+        private long _disconnectGate;
 
         public MqttClient(IMqttClientAdapterFactory channelFactory, IMqttNetLogger logger)
         {
@@ -55,12 +55,12 @@ namespace MQTTnet.Client
 
             try
             {
-                _cancellationTokenSource = new CancellationTokenSource();
-                _disconnectReason = new TaskCompletionSource<bool>();
                 _options = options;
                 _packetIdentifierProvider.Reset();
                 _packetDispatcher.Reset();
 
+                _cancellationTokenSource = new CancellationTokenSource();
+                _disconnectGate = 0;
                 _adapter = _adapterFactory.CreateClientAdapter(options, _logger);
                 
                 _logger.Verbose($"Trying to connect with server ({_options.ChannelOptions}).");
@@ -88,10 +88,12 @@ namespace MQTTnet.Client
             catch (Exception exception)
             {
                 _logger.Error(exception, "Error while connecting with server.");
-                if (_disconnectReason.TrySetException(exception))
+
+                if (!DisconnectIsPending())
                 {
                     await DisconnectInternalAsync(null, exception).ConfigureAwait(false);
                 }
+
                 throw;
             }
         }
@@ -109,7 +111,7 @@ namespace MQTTnet.Client
             }
             finally
             {
-                if (_disconnectReason.TrySetCanceled())
+                if (!DisconnectIsPending())
                 {
                     await DisconnectInternalAsync(null, null).ConfigureAwait(false);
                 }
@@ -184,10 +186,12 @@ namespace MQTTnet.Client
 
         public void Dispose()
         {
+            _cancellationTokenSource?.Cancel(false);
             _cancellationTokenSource?.Dispose();
             _cancellationTokenSource = null;
 
             _adapter?.Dispose();
+            _adapter = null;
         }
 
         private async Task<MqttV3ConnAckPacket> AuthenticateAsync(MqttApplicationMessage willApplicationMessage, CancellationToken cancellationToken)
@@ -213,7 +217,7 @@ namespace MQTTnet.Client
 
         private void ThrowIfNotConnected()
         {
-            if (!IsConnected) throw new MqttCommunicationException("The client is not connected.");
+            if (!IsConnected || Interlocked.Read(ref _disconnectGate) == 1) throw new MqttCommunicationException("The client is not connected.");
         }
 
         private void ThrowIfConnected(string message)
@@ -223,9 +227,10 @@ namespace MQTTnet.Client
 
         private async Task DisconnectInternalAsync(Task sender, Exception exception)
         {
-            InitiateDisconnect();
-
             var clientWasConnected = IsConnected;
+
+            InitiateDisconnect();
+            
             IsConnected = false;
 
             try
@@ -246,10 +251,7 @@ namespace MQTTnet.Client
             }
             finally
             {
-                _adapter?.Dispose();
-                _adapter = null;
-                _cancellationTokenSource?.Dispose();
-                _cancellationTokenSource = null;
+                Dispose();
                 _cleanDisconnectInitiated = false;
 
                 _logger.Info("Disconnected.");
@@ -263,16 +265,16 @@ namespace MQTTnet.Client
             {
                 try
                 {
-                    if (_cancellationTokenSource == null || _cancellationTokenSource.IsCancellationRequested)
+                    if (_cancellationTokenSource?.IsCancellationRequested == true)
                     {
                         return;
                     }
 
-                    _cancellationTokenSource.Cancel(false);
+                    _cancellationTokenSource?.Cancel(false);
                 }
-                catch (Exception adapterException)
+                catch (Exception exception)
                 {
-                    _logger.Warning(adapterException, "Error while initiating disconnect.");
+                    _logger.Warning(exception, "Error while initiating disconnect.");
                 }
             }
         }
@@ -360,7 +362,7 @@ namespace MQTTnet.Client
                     _logger.Error(exception, "Unhandled exception while sending/receiving keep alive packets.");
                 }
 
-                if (_disconnectReason.TrySetException(exception))
+                if (!DisconnectIsPending())
                 {
                     await DisconnectInternalAsync(_keepAliveMessageSenderTask, exception).ConfigureAwait(false);
                 }
@@ -379,8 +381,10 @@ namespace MQTTnet.Client
             {
                 while (!cancellationToken.IsCancellationRequested)
                 {
-                    var packet = await _adapter.ReceivePacketAsync(TimeSpan.Zero, cancellationToken).ConfigureAwait(false);
-                    if (packet != null)
+                    var packet = await _adapter.ReceivePacketAsync(TimeSpan.Zero, cancellationToken)
+                        .ConfigureAwait(false);
+
+                    if (packet != null && !cancellationToken.IsCancellationRequested)
                     {
                         await ProcessReceivedPacketAsync(packet, cancellationToken).ConfigureAwait(false);
                     }
@@ -407,7 +411,7 @@ namespace MQTTnet.Client
 
                 _packetDispatcher.Dispatch(exception);
 
-                if (_disconnectReason.TrySetException(exception))
+                if (!DisconnectIsPending())
                 {
                     await DisconnectInternalAsync(_packetReceiverTask, exception).ConfigureAwait(false);
                 }
@@ -493,16 +497,20 @@ namespace MQTTnet.Client
 
         private void StartReceivingPackets(CancellationToken cancellationToken)
         {
-            _packetReceiverTask = Task.Run(
+            _packetReceiverTask = Task.Factory.StartNew(
                 () => ReceivePacketsAsync(cancellationToken),
-                cancellationToken);
+                cancellationToken,
+                TaskCreationOptions.LongRunning, 
+                TaskScheduler.Default);
         }
 
         private void StartSendingKeepAliveMessages(CancellationToken cancellationToken)
         {
-            _keepAliveMessageSenderTask = Task.Run(
+            _keepAliveMessageSenderTask = Task.Factory.StartNew(
                 () => SendKeepAliveMessagesAsync(cancellationToken),
-                cancellationToken);
+                cancellationToken,
+                TaskCreationOptions.LongRunning,
+                TaskScheduler.Default);
         }
 
         private void FireApplicationMessageReceivedEvent(MqttPublishPacket publishPacket)
@@ -538,5 +546,10 @@ namespace MQTTnet.Client
             {
             }
         }
+
+        private bool DisconnectIsPending()
+        {
+            return Interlocked.CompareExchange(ref _disconnectGate, 1, 0) != 0;
+        }
     }
-}
+}

Source/MQTTnet/Implementations/MqttTcpChannel.cs

@@ -116,7 +116,7 @@ namespace MQTTnet.Implementations
                 return true;
             }
 
-            if (chain.ChainStatus.Any(c => c.Status == X509ChainStatusFlags.RevocationStatusUnknown || c.Status == X509ChainStatusFlags.Revoked || c.Status == X509ChainStatusFlags.RevocationStatusUnknown))
+            if (chain.ChainStatus.Any(c => c.Status == X509ChainStatusFlags.RevocationStatusUnknown || c.Status == X509ChainStatusFlags.Revoked || c.Status == X509ChainStatusFlags.OfflineRevocation))
             {
                 if (!_options.TlsOptions.IgnoreCertificateRevocationErrors)
                 {

Source/MQTTnet/Implementations/MqttTcpServerListener.cs

@@ -20,8 +20,8 @@ namespace MQTTnet.Implementations
         private readonly CancellationToken _cancellationToken;
         private readonly AddressFamily _addressFamily;
         private readonly MqttServerTcpEndpointBaseOptions _options;
+        private readonly MqttServerTlsTcpEndpointOptions _tlsOptions;
         private readonly X509Certificate2 _tlsCertificate;
-
         private Socket _socket;
 
         public MqttTcpServerListener(
@@ -36,6 +36,11 @@ namespace MQTTnet.Implementations
             _tlsCertificate = tlsCertificate;
             _cancellationToken = cancellationToken;
             _logger = logger.CreateChildLogger(nameof(MqttTcpServerListener));
+            
+            if (_options is MqttServerTlsTcpEndpointOptions tlsOptions)
+            {
+                _tlsOptions = tlsOptions;
+            }
         }
 
         public event EventHandler<MqttServerAdapterClientAcceptedEventArgs> ClientAccepted;
@@ -75,7 +80,7 @@ namespace MQTTnet.Implementations
                     if (_tlsCertificate != null)
                     {
                         sslStream = new SslStream(new NetworkStream(clientSocket), false);
-                        await sslStream.AuthenticateAsServerAsync(_tlsCertificate, false, SslProtocols.Tls12, false).ConfigureAwait(false);
+                        await sslStream.AuthenticateAsServerAsync(_tlsCertificate, false, _tlsOptions.SslProtocol, false).ConfigureAwait(false);
                     }
 
                     _logger.Verbose("Client '{0}' accepted by TCP listener '{1}, {2}'.",

Source/MQTTnet/Internal/BlockingQueue.cs

@@ -0,0 +1,78 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+
+namespace MQTTnet.Internal
+{
+    public class BlockingQueue<TItem>
+    {
+        private readonly object _syncRoot = new object();
+        private readonly LinkedList<TItem> _items = new LinkedList<TItem>();
+        private readonly ManualResetEvent _gate = new ManualResetEvent(false);
+
+        public int Count
+        {
+            get
+            {
+                lock (_syncRoot)
+                {
+                    return _items.Count;
+                }
+            }
+        }
+
+        public void Enqueue(TItem item)
+        {
+            if (item == null) throw new ArgumentNullException(nameof(item));
+
+            lock (_syncRoot)
+            {
+                _items.AddLast(item);
+                _gate.Set();
+            }
+        }
+
+        public TItem Dequeue()
+        {
+            while (true)
+            {
+                lock (_syncRoot)
+                {
+                    if (_items.Count > 0)
+                    {
+                        var item = _items.First.Value;
+                        _items.RemoveFirst();
+
+                        return item;
+                    }
+
+                    if (_items.Count == 0)
+                    {
+                        _gate.Reset();
+                    }
+                }
+
+                _gate.WaitOne();
+            }
+        }
+
+        public TItem RemoveFirst()
+        {
+            lock (_syncRoot)
+            {
+                var item = _items.First;
+                _items.RemoveFirst();
+
+                return item.Value;
+            }
+        }
+
+        public void Clear()
+        {
+            lock (_syncRoot)
+            {
+                _items.Clear();
+            }
+        }
+    }
+}

Source/MQTTnet/MQTTnet.csproj

@@ -54,7 +54,7 @@
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)'=='uap10.0'">
-    <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform" Version="6.1.5" />
+    <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform" Version="6.1.9" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)'=='net452'">

Source/MQTTnet/Server/IMqttServer.cs

@@ -16,8 +16,14 @@ namespace MQTTnet.Server
         
         IMqttServerOptions Options { get; }
 
+        [Obsolete("This method is no longer async. Use the not async method.")]
         Task<IList<IMqttClientSessionStatus>> GetClientSessionsStatusAsync();
 
+        IList<IMqttClientSessionStatus> GetClientSessionsStatus();
+
+        IList<MqttApplicationMessage> GetRetainedMessages();
+        Task ClearRetainedMessagesAsync();
+
         Task SubscribeAsync(string clientId, IList<TopicFilter> topicFilters);
         Task UnsubscribeAsync(string clientId, IList<string> topicFilters);
 

Source/MQTTnet/Server/IMqttServerFactory.cs

@@ -8,6 +8,8 @@ namespace MQTTnet.Server
     {
         IMqttServer CreateMqttServer();
 
+        IMqttServer CreateMqttServer(IMqttNetLogger logger);
+
         IMqttServer CreateMqttServer(IEnumerable<IMqttServerAdapter> adapters, IMqttNetLogger logger);
     }
 }

Source/MQTTnet/Server/IMqttServerOptions.cs

@@ -14,7 +14,7 @@ namespace MQTTnet.Server
         Action<MqttConnectionValidatorContext> ConnectionValidator { get; }
         Action<MqttSubscriptionInterceptorContext> SubscriptionInterceptor { get; }
         Action<MqttApplicationMessageInterceptorContext> ApplicationMessageInterceptor { get; }
-        Action<MqttClientMessageQueueInterceptorContext> ClientMessageQueueInterceptor { get; set; }
+        Action<MqttClientMessageQueueInterceptorContext> ClientMessageQueueInterceptor { get; }
 
         MqttServerTcpEndpointOptions DefaultEndpointOptions { get; }
         MqttServerTlsTcpEndpointOptions TlsEndpointOptions { get; }

Source/MQTTnet/Server/MqttClientSession.cs

@@ -137,7 +137,9 @@ namespace MQTTnet.Server
 
                 _cleanupHandle?.Dispose();
                 _cleanupHandle = null;
-
+                
+                _adapter = null;
+                _cancellationTokenSource?.Cancel(false);
                 _cancellationTokenSource?.Dispose();
                 _cancellationTokenSource = null;
             }
@@ -289,7 +291,9 @@ namespace MQTTnet.Server
         {
             _pendingPacketsQueue?.Dispose();
 
+            _cancellationTokenSource?.Cancel ();
             _cancellationTokenSource?.Dispose();
+            _cancellationTokenSource = null;
         }
 
         private void ProcessReceivedPacket(IMqttChannelAdapter adapter, MqttBasePacket packet, CancellationToken cancellationToken)

Source/MQTTnet/Server/MqttClientSessionsManager.cs

@@ -66,7 +66,7 @@ namespace MQTTnet.Server
             return Task.Run(() => RunSession(clientAdapter, _cancellationToken), _cancellationToken);
         }
 
-        public Task<IList<IMqttClientSessionStatus>> GetClientStatusAsync()
+        public IList<IMqttClientSessionStatus> GetClientStatus()
         {
             var result = new List<IMqttClientSessionStatus>();
 
@@ -78,7 +78,7 @@ namespace MQTTnet.Server
                 result.Add(status);
             }
 
-            return Task.FromResult((IList<IMqttClientSessionStatus>)result);
+            return result;
         }
 
         public void EnqueueApplicationMessage(MqttClientSession senderClientSession, MqttPublishPacket publishPacket)

Source/MQTTnet/Server/MqttRetainedMessagesManager.cs

@@ -52,7 +52,51 @@ namespace MQTTnet.Server
 
             try
             {
-                await HandleMessageInternalAsync(clientId, applicationMessage).ConfigureAwait(false);
+                List<MqttApplicationMessage> messagesForSave = null;
+                lock (_messages)
+                {
+                    var saveIsRequired = false;
+
+                    if (applicationMessage.Payload?.Length == 0)
+                    {
+                        saveIsRequired = _messages.Remove(applicationMessage.Topic);
+                        _logger.Verbose("Client '{0}' cleared retained message for topic '{1}'.", clientId, applicationMessage.Topic);
+                    }
+                    else
+                    {
+                        if (!_messages.TryGetValue(applicationMessage.Topic, out var existingMessage))
+                        {
+                            _messages[applicationMessage.Topic] = applicationMessage;
+                            saveIsRequired = true;
+                        }
+                        else
+                        {
+                            if (existingMessage.QualityOfServiceLevel != applicationMessage.QualityOfServiceLevel || !existingMessage.Payload.SequenceEqual(applicationMessage.Payload ?? new byte[0]))
+                            {
+                                _messages[applicationMessage.Topic] = applicationMessage;
+                                saveIsRequired = true;
+                            }
+                        }
+
+                        _logger.Verbose("Client '{0}' set retained message for topic '{1}'.", clientId, applicationMessage.Topic);
+                    }
+
+                    if (saveIsRequired)
+                    {
+                        messagesForSave = new List<MqttApplicationMessage>(_messages.Values);
+                    }
+                }
+
+                if (messagesForSave == null)
+                {
+                    _logger.Verbose("Skipped saving retained messages because no changes were detected.");
+                    return;
+                }
+
+                if (_options.Storage != null)
+                {
+                    await _options.Storage.SaveRetainedMessagesAsync(messagesForSave).ConfigureAwait(false);
+                }
             }
             catch (Exception exception)
             {
@@ -84,52 +128,27 @@ namespace MQTTnet.Server
             return retainedMessages;
         }
 
-        private async Task HandleMessageInternalAsync(string clientId, MqttApplicationMessage applicationMessage)
+        public IList<MqttApplicationMessage> GetMessages()
         {
-            var saveIsRequired = false;
-
             lock (_messages)
             {
-                if (applicationMessage.Payload?.Length == 0)
-                {
-                    saveIsRequired = _messages.Remove(applicationMessage.Topic);
-                    _logger.Info("Client '{0}' cleared retained message for topic '{1}'.", clientId, applicationMessage.Topic);
-                }
-                else
-                {
-                    if (!_messages.TryGetValue(applicationMessage.Topic, out var existingMessage))
-                    {
-                        _messages[applicationMessage.Topic] = applicationMessage;
-                        saveIsRequired = true;
-                    }
-                    else
-                    {
-                        if (existingMessage.QualityOfServiceLevel != applicationMessage.QualityOfServiceLevel || !existingMessage.Payload.SequenceEqual(applicationMessage.Payload ?? new byte[0]))
-                        {
-                            _messages[applicationMessage.Topic] = applicationMessage;
-                            saveIsRequired = true;
-                        }
-                    }
-
-                    _logger.Info("Client '{0}' set retained message for topic '{1}'.", clientId, applicationMessage.Topic);
-                }
+                return _messages.Values.ToList();
             }
+        }
 
-            if (!saveIsRequired)
+        public Task ClearMessagesAsync()
+        {
+            lock (_messages)
             {
-                _logger.Verbose("Skipped saving retained messages because no changes were detected.");
+                _messages.Clear();
             }
 
-            if (saveIsRequired && _options.Storage != null)
+            if (_options.Storage != null)
             {
-                List<MqttApplicationMessage> messages;
-                lock (_messages)
-                {
-                    messages = _messages.Values.ToList();
-                }
-
-                await _options.Storage.SaveRetainedMessagesAsync(messages).ConfigureAwait(false);
+                return _options.Storage.SaveRetainedMessagesAsync(new List<MqttApplicationMessage>());
             }
+
+            return Task.FromResult((object)null);
         }
     }
 }

Source/MQTTnet/Server/MqttServer.cs

@@ -41,7 +41,17 @@ namespace MQTTnet.Server
 
         public Task<IList<IMqttClientSessionStatus>> GetClientSessionsStatusAsync()
         {
-            return _clientSessionsManager.GetClientStatusAsync();
+            return Task.FromResult(_clientSessionsManager.GetClientStatus());
+        }
+
+        public IList<IMqttClientSessionStatus> GetClientSessionsStatus()
+        {
+            return _clientSessionsManager.GetClientStatus();
+        }
+
+        public IList<MqttApplicationMessage> GetRetainedMessages()
+        {
+            return _retainedMessagesManager.GetMessages();
         }
 
         public Task SubscribeAsync(string clientId, IList<TopicFilter> topicFilters)
@@ -129,6 +139,11 @@ namespace MQTTnet.Server
             }
         }
 
+        public Task ClearRetainedMessagesAsync()
+        {
+            return _retainedMessagesManager?.ClearMessagesAsync();
+        }
+
         internal void OnClientConnected(string clientId)
         {
             _logger.Info("Client '{0}': Connected.", clientId);

Source/MQTTnet/Server/MqttServerOptionsBuilder.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Net;
+using System.Security.Authentication;
 
 namespace MQTTnet.Server
 {
@@ -80,6 +81,12 @@ namespace MQTTnet.Server
             return this;
         }
 
+        public MqttServerOptionsBuilder WithEncryptionSslProtocol(SslProtocols value)
+        {
+            _options.TlsEndpointOptions.SslProtocol = value;
+            return this;
+        }
+
         public MqttServerOptionsBuilder WithoutEncryptedEndpoint()
         {
             _options.TlsEndpointOptions.IsEnabled = false;

Source/MQTTnet/Server/MqttServerTlsTcpEndpointOptions.cs

@@ -1,4 +1,6 @@
-namespace MQTTnet.Server
+using System.Security.Authentication;
+
+namespace MQTTnet.Server
 {
     public class MqttServerTlsTcpEndpointOptions : MqttServerTcpEndpointBaseOptions
     {
@@ -8,5 +10,8 @@
         }
 
         public byte[] Certificate { get; set; }
+
+
+        public SslProtocols SslProtocol { get; set; } = SslProtocols.Tls12;
     }
 }