private async Task DisconnectInternalAsync(Task sender, Exception exception)
{
var clientWasConnected = IsConnected;
InitiateDisconnect();
IsConnected = false;
try
{
if (_adapter != null)
{
await _adapter.DisconnectAsync(Options.CommunicationTimeout, CancellationToken.None).ConfigureAwait(false);
}
await WaitForTaskAsync(_packetReceiverTask, sender).ConfigureAwait(false);
await WaitForTaskAsync(_keepAliveMessageSenderTask, sender).ConfigureAwait(false);
_logger.Verbose("Disconnected from adapter.");
}
catch (Exception adapterException)
{
_logger.Warning(adapterException, "Error while disconnecting from adapter.");
}
finally
{
Dispose();
_cleanDisconnectInitiated = false;
_logger.Info("Disconnected.");
Disconnected?.Invoke(this, new MqttClientDisconnectedEventArgs(clientWasConnected, exception));
}
}
public bool Start(bool treatErrorsAsWarning, CancellationToken cancellationToken)
{
try
{
var boundIp = _options.BoundInterNetworkAddress;
if (_addressFamily == AddressFamily.InterNetworkV6)
{
boundIp = _options.BoundInterNetworkV6Address;
}
_localEndPoint = new IPEndPoint(boundIp, _options.Port);
_logger.Info($"Starting TCP listener for {_localEndPoint} TLS={_tlsCertificate != null}.");
_socket = new Socket(_addressFamily, SocketType.Stream, ProtocolType.Tcp);
_socket.Bind(_localEndPoint);
_socket.Listen(_options.ConnectionBacklog);
Task.Run(() => AcceptClientConnectionsAsync(cancellationToken), cancellationToken).Forget(_logger);
return(true);
}
catch (Exception exception)
{
if (!treatErrorsAsWarning)
{
throw;
}
_logger.Warning(exception, "Error while creating listener socket for local end point '{0}'.", _localEndPoint);
return(false);
}
}
private async Task RunAsync(int keepAlivePeriod, CancellationToken cancellationToken)
{
try
{
_lastPacketReceivedTracker.Restart();
_lastNonKeepAlivePacketReceivedTracker.Restart();
while (!cancellationToken.IsCancellationRequested)
{
// Values described here: [MQTT-3.1.2-24].
if (!_isPaused && _lastPacketReceivedTracker.Elapsed.TotalSeconds > keepAlivePeriod * 1.5D)
{
_logger.Warning(null, "Client '{0}': Did not receive any packet or keep alive signal.", _clientSession.ClientId);
_clientSession.Stop(MqttClientDisconnectType.NotClean);
return;
}
await Task.Delay(keepAlivePeriod, cancellationToken).ConfigureAwait(false);
}
}
catch (OperationCanceledException)
{
}
catch (Exception exception)
{
_logger.Error(exception, "Client '{0}': Unhandled exception while checking keep alive timeouts.", _clientSession.ClientId);
}
finally
{
_logger.Verbose("Client {0}: Stopped checking keep alive timeout.", _clientSession.ClientId);
}
}
private async Task DisconnectInternalAsync(Task sender, Exception exception, MqttClientAuthenticateResult authenticateResult)
{
var clientWasConnected = IsConnected;
TryInitiateDisconnect();
IsConnected = false;
try
{
if (_adapter != null)
{
_logger.Verbose("Disconnecting [Timeout={0}]", Options.CommunicationTimeout);
await _adapter.DisconnectAsync(Options.CommunicationTimeout, CancellationToken.None).ConfigureAwait(false);
}
_logger.Verbose("Disconnected from adapter.");
}
catch (Exception adapterException)
{
_logger.Warning(adapterException, "Error while disconnecting from adapter.");
}
try
{
var receiverTask = WaitForTaskAsync(_packetReceiverTask, sender);
var keepAliveTask = WaitForTaskAsync(_keepAlivePacketsSenderTask, sender);
await Task.WhenAll(receiverTask, keepAliveTask).ConfigureAwait(false);
}
catch (Exception e)
{
_logger.Warning(e, "Error while waiting for internal tasks.");
}
finally
{
Cleanup();
_cleanDisconnectInitiated = false;
_logger.Info("Disconnected.");
var disconnectedHandler = DisconnectedHandler;
if (disconnectedHandler != null)
{
// This handler must be executed in a new thread because otherwise a dead lock may happen
// when trying to reconnect in that handler etc.
Task.Run(() => disconnectedHandler.HandleDisconnectedAsync(new MqttClientDisconnectedEventArgs(clientWasConnected, exception, authenticateResult))).Forget(_logger);
}
}
}
private async Task TryMaintainConnectionAsync(CancellationToken cancellationToken)
{
try
{
var connectionState = await ReconnectIfRequiredAsync().ConfigureAwait(false);
if (connectionState == ReconnectionResult.NotConnected)
{
StopPublishing();
await Task.Delay(Options.AutoReconnectDelay, cancellationToken).ConfigureAwait(false);
return;
}
if (connectionState == ReconnectionResult.Reconnected || _subscriptionsNotPushed)
{
await SynchronizeSubscriptionsAsync().ConfigureAwait(false);
StartPublishing();
return;
}
if (connectionState == ReconnectionResult.StillConnected)
{
await Task.Delay(Options.ConnectionCheckInterval, cancellationToken).ConfigureAwait(false);
}
}
catch (OperationCanceledException)
{
}
catch (MqttCommunicationException exception)
{
_logger.Warning(exception, "Communication exception while maintaining connection.");
}
catch (Exception exception)
{
_logger.Error(exception, "Unhandled exception while maintaining connection.");
}
}
private async void OnConnectionReceivedAsync(StreamSocketListener sender, StreamSocketListenerConnectionReceivedEventArgs args)
{
try
{
var clientHandler = ClientHandler;
if (clientHandler != null)
{
X509Certificate2 clientCertificate = null;
if (args.Socket.Control.ClientCertificate != null)
{
try
{
clientCertificate = new X509Certificate2(args.Socket.Control.ClientCertificate.GetCertificateBlob().ToArray());
}
catch (Exception exception)
{
_logger.Warning(exception, "Unable to convert UWP certificate to X509Certificate2.");
}
}
using (var clientAdapter = new MqttChannelAdapter(new MqttTcpChannel(args.Socket, clientCertificate, _options), new MqttPacketFormatterAdapter(), _logger))
{
await clientHandler(clientAdapter).ConfigureAwait(false);
}
}
}
catch (Exception exception)
{
if (exception is ObjectDisposedException)
{
// It can happen that the listener socket is accessed after the cancellation token is already set and the listener socket is disposed.
return;
}
_logger.Error(exception, "Error while handling client connection.");
}
finally
{
try
{
args.Socket.Dispose();
}
catch (Exception exception)
{
_logger.Error(exception, "Error while cleaning up client connection");
}
}
}
public bool Start(bool treatErrorsAsWarning, CancellationToken cancellationToken)
{
try
{
var boundIp = _options.BoundInterNetworkAddress;
if (_addressFamily == AddressFamily.InterNetworkV6)
{
boundIp = _options.BoundInterNetworkV6Address;
}
_localEndPoint = new IPEndPoint(boundIp, _options.Port);
_logger.Info($"Starting TCP listener for {_localEndPoint} TLS={_tlsCertificate != null}.");
_socket = new Socket(_addressFamily, SocketType.Stream, ProtocolType.Tcp);
// Usage of socket options is described here: https://docs.microsoft.com/en-us/dotnet/api/system.net.sockets.socket.setsocketoption?view=netcore-2.2
if (_options.ReuseAddress)
{
_socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
}
if (_options.NoDelay)
{
_socket.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.NoDelay, true);
}
_socket.Bind(_localEndPoint);
_socket.Listen(_options.ConnectionBacklog);
Task.Run(() => AcceptClientConnectionsAsync(cancellationToken), cancellationToken).Forget(_logger);
return(true);
}
catch (Exception exception)
{
if (!treatErrorsAsWarning)
{
throw;
}
_logger.Warning(exception, "Error while creating listener socket for local end point '{0}'.", _localEndPoint);
return(false);
}
}
private async Task RunAsync(int keepAlivePeriod, CancellationToken cancellationToken)
{
try
{
_lastPacketReceivedTracker.Restart();
_lastNonKeepAlivePacketReceivedTracker.Restart();
while (!cancellationToken.IsCancellationRequested)
{
// Values described here: [MQTT-3.1.2-24].
// If the client sends 5 sec. the server will allow up to 7.5 seconds.
// If the client sends 1 sec. the server will allow up to 1.5 seconds.
if (!_isPaused && _lastPacketReceivedTracker.Elapsed.TotalSeconds >= keepAlivePeriod * 1.5D)
{
_logger.Warning(null, "Client '{0}': Did not receive any packet or keep alive signal.", _clientSession.ClientId);
_clientSession.Stop(MqttClientDisconnectType.NotClean);
return;
}
// The server checks the keep alive timeout every 50 % of the overall keep alive timeout
// because the server allows 1.5 times the keep alive value. This means that a value of 5 allows
// up to 7.5 seconds. With an interval of 2.5 (5 / 2) the 7.5 is also affected. Waiting the whole
// keep alive time will hit at 10 instead of 7.5 (but only one time instead of two times).
await Task.Delay(TimeSpan.FromSeconds(keepAlivePeriod * 0.5D), cancellationToken).ConfigureAwait(false);
}
}
catch (OperationCanceledException)
{
}
catch (Exception exception)
{
_logger.Error(exception, "Client '{0}': Unhandled exception while checking keep alive timeouts.", _clientSession.ClientId);
}
finally
{
_logger.Verbose("Client '{0}': Stopped checking keep alive timeout.", _clientSession.ClientId);
}
}
private async Task DisconnectInternalAsync(Task sender, Exception exception, MqttClientAuthenticateResult authenticateResult)
{
var clientWasConnected = IsConnected;
InitiateDisconnect();
IsConnected = false;
try
{
if (_adapter != null)
{
_logger.Verbose("Disconnecting [Timeout={0}]", Options.CommunicationTimeout);
await _adapter.DisconnectAsync(Options.CommunicationTimeout, CancellationToken.None).ConfigureAwait(false);
}
await WaitForTaskAsync(_packetReceiverTask, sender).ConfigureAwait(false);
await WaitForTaskAsync(_keepAlivePacketsSenderTask, sender).ConfigureAwait(false);
_logger.Verbose("Disconnected from adapter.");
}
catch (Exception adapterException)
{
_logger.Warning(adapterException, "Error while disconnecting from adapter.");
}
finally
{
Dispose();
_cleanDisconnectInitiated = false;
_logger.Info("Disconnected.");
var disconnectedHandler = DisconnectedHandler;
if (disconnectedHandler != null)
{
await disconnectedHandler.HandleDisconnectedAsync(new MqttClientDisconnectedEventArgs(clientWasConnected, exception, authenticateResult)).ConfigureAwait(false);
}
}
}
private async Task RunInternalAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
{
if (connectPacket == null)
{
throw new ArgumentNullException(nameof(connectPacket));
}
if (adapter == null)
{
throw new ArgumentNullException(nameof(adapter));
}
try
{
if (_cancellationTokenSource != null)
{
Stop(MqttClientDisconnectType.Clean, true);
}
adapter.ReadingPacketStarted += OnAdapterReadingPacketStarted;
adapter.ReadingPacketCompleted += OnAdapterReadingPacketCompleted;
_cancellationTokenSource = new CancellationTokenSource();
//workaround for https://github.com/dotnet/corefx/issues/24430
#pragma warning disable 4014
_cleanupHandle = _cancellationTokenSource.Token.Register(async() =>
{
await TryDisconnectAdapterAsync(adapter).ConfigureAwait(false);
TryDisposeAdapter(adapter);
});
#pragma warning restore 4014
//end workaround
_wasCleanDisconnect = false;
_willMessage = connectPacket.WillMessage;
_pendingPacketsQueue.Start(adapter, _cancellationTokenSource.Token);
_keepAliveMonitor.Start(connectPacket.KeepAlivePeriod, _cancellationTokenSource.Token);
_adapterEndpoint = adapter.Endpoint;
_adapterProtocolVersion = adapter.PacketSerializer.ProtocolVersion;
while (!_cancellationTokenSource.IsCancellationRequested)
{
var packet = await adapter.ReceivePacketAsync(TimeSpan.Zero, _cancellationTokenSource.Token).ConfigureAwait(false);
if (packet != null)
{
_keepAliveMonitor.PacketReceived(packet);
ProcessReceivedPacket(adapter, packet, _cancellationTokenSource.Token);
}
}
}
catch (OperationCanceledException)
{
}
catch (Exception exception)
{
if (exception is MqttCommunicationException)
{
if (exception is MqttCommunicationClosedGracefullyException)
{
_logger.Verbose("Client '{0}': Connection closed gracefully.", ClientId);
}
else
{
_logger.Warning(exception, "Client '{0}': Communication exception while receiving client packets.", ClientId);
}
}
else
{
_logger.Error(exception, "Client '{0}': Unhandled exception while receiving client packets.", ClientId);
}
Stop(MqttClientDisconnectType.NotClean, true);
}
finally
{
_adapterEndpoint = null;
_adapterProtocolVersion = null;
// Uncomment as soon as the workaround above is no longer needed.
//await TryDisconnectAdapterAsync(adapter).ConfigureAwait(false);
//TryDisposeAdapter(adapter);
_cleanupHandle?.Dispose();
_cleanupHandle = null;
_cancellationTokenSource?.Cancel(false);
_cancellationTokenSource?.Dispose();
_cancellationTokenSource = null;
}
}
private async Task TrySendNextQueuedPacketAsync(IMqttChannelAdapter adapter, CancellationToken cancellationToken)
{
MqttBasePacket packet = null;
try
{
lock (_queue)
{
if (_queue.Count > 0)
{
packet = _queue.Dequeue();
}
}
if (packet == null)
{
await _queueAutoResetEvent.WaitOneAsync(cancellationToken).ConfigureAwait(false);
return;
}
if (cancellationToken.IsCancellationRequested)
{
return;
}
adapter.SendPacketAsync(packet, cancellationToken).GetAwaiter().GetResult();
_logger.Verbose("Enqueued packet sent (ClientId: {0}).", _clientSession.ClientId);
}
catch (Exception exception)
{
if (exception is MqttCommunicationTimedOutException)
{
_logger.Warning(exception, "Sending publish packet failed: Timeout (ClientId: {0}).", _clientSession.ClientId);
}
else if (exception is MqttCommunicationException)
{
_logger.Warning(exception, "Sending publish packet failed: Communication exception (ClientId: {0}).", _clientSession.ClientId);
}
else if (exception is OperationCanceledException)
{
}
else
{
_logger.Error(exception, "Sending publish packet failed (ClientId: {0}).", _clientSession.ClientId);
}
if (packet is MqttPublishPacket publishPacket)
{
if (publishPacket.QualityOfServiceLevel > MqttQualityOfServiceLevel.AtMostOnce)
{
publishPacket.Dup = true;
Enqueue(publishPacket);
}
}
if (!cancellationToken.IsCancellationRequested)
{
_clientSession.Stop(MqttClientDisconnectType.NotClean);
}
}
}
private async Task <MqttClientDisconnectType> RunInternalAsync()
{
var disconnectType = MqttClientDisconnectType.NotClean;
try
{
_logger.Info("Client '{0}': Session started.", ClientId);
_channelAdapter.ReadingPacketStartedCallback = OnAdapterReadingPacketStarted;
_channelAdapter.ReadingPacketCompletedCallback = OnAdapterReadingPacketCompleted;
Session.WillMessage = _connectPacket.WillMessage;
#pragma warning disable 4014
Task.Run(() => SendPendingPacketsAsync(_cancellationToken.Token), _cancellationToken.Token);
#pragma warning restore 4014
// TODO: Change to single thread in SessionManager. Or use SessionManager and stats from KeepAliveMonitor.
_keepAliveMonitor.Start(_connectPacket.KeepAlivePeriod, _cancellationToken.Token);
await SendAsync(
new MqttConnAckPacket
{
ReturnCode = MqttConnectReturnCode.ConnectionAccepted,
ReasonCode = MqttConnectReasonCode.Success,
IsSessionPresent = !Session.IsCleanSession
}).ConfigureAwait(false);
Session.IsCleanSession = false;
while (!_cancellationToken.IsCancellationRequested)
{
var packet = await _channelAdapter.ReceivePacketAsync(TimeSpan.Zero, _cancellationToken.Token).ConfigureAwait(false);
if (packet == null)
{
// The client has closed the connection gracefully.
break;
}
Interlocked.Increment(ref _sentPacketsCount);
_lastPacketReceivedTimestamp = DateTime.UtcNow;
if (!(packet is MqttPingReqPacket || packet is MqttPingRespPacket))
{
_lastNonKeepAlivePacketReceivedTimestamp = _lastPacketReceivedTimestamp;
}
_keepAliveMonitor.PacketReceived();
if (packet is MqttPublishPacket publishPacket)
{
await HandleIncomingPublishPacketAsync(publishPacket).ConfigureAwait(false);
continue;
}
if (packet is MqttPubRelPacket pubRelPacket)
{
var pubCompPacket = new MqttPubCompPacket
{
PacketIdentifier = pubRelPacket.PacketIdentifier,
ReasonCode = MqttPubCompReasonCode.Success
};
await SendAsync(pubCompPacket).ConfigureAwait(false);
continue;
}
if (packet is MqttSubscribePacket subscribePacket)
{
await HandleIncomingSubscribePacketAsync(subscribePacket).ConfigureAwait(false);
continue;
}
if (packet is MqttUnsubscribePacket unsubscribePacket)
{
await HandleIncomingUnsubscribePacketAsync(unsubscribePacket).ConfigureAwait(false);
continue;
}
if (packet is MqttPingReqPacket)
{
await SendAsync(new MqttPingRespPacket()).ConfigureAwait(false);
continue;
}
if (packet is MqttDisconnectPacket)
{
Session.WillMessage = null;
disconnectType = MqttClientDisconnectType.Clean;
StopInternal();
break;
}
_packetDispatcher.Dispatch(packet);
}
}
catch (OperationCanceledException)
{
}
catch (Exception exception)
{
if (exception is MqttCommunicationException)
{
_logger.Warning(exception, "Client '{0}': Communication exception while receiving client packets.", ClientId);
}
else
{
_logger.Error(exception, "Client '{0}': Unhandled exception while receiving client packets.", ClientId);
}
StopInternal();
}
finally
{
if (Session.WillMessage != null)
{
_sessionsManager.DispatchApplicationMessage(Session.WillMessage, this);
Session.WillMessage = null;
}
_packetDispatcher.Reset();
_channelAdapter.ReadingPacketStartedCallback = null;
_channelAdapter.ReadingPacketCompletedCallback = null;
_logger.Info("Client '{0}': Session stopped.", ClientId);
_packageReceiverTask = null;
}
return(disconnectType);
}
private async Task HandleClientAsync(IMqttChannelAdapter channelAdapter, CancellationToken cancellationToken)
{
var disconnectType = MqttClientDisconnectType.NotClean;
string clientId = null;
try
{
var firstPacket = await channelAdapter.ReceivePacketAsync(_options.DefaultCommunicationTimeout, cancellationToken).ConfigureAwait(false);
if (!(firstPacket is MqttConnectPacket connectPacket))
{
_logger.Warning(null, "The first packet from client '{0}' was no 'CONNECT' packet [MQTT-3.1.0-1].", channelAdapter.Endpoint);
return;
}
clientId = connectPacket.ClientId;
var validatorContext = await ValidateConnectionAsync(connectPacket, channelAdapter).ConfigureAwait(false);
if (validatorContext.ReasonCode != MqttConnectReasonCode.Success)
{
// Send failure response here without preparing a session. The result for a successful connect
// will be sent from the session itself.
var connAckPacket = channelAdapter.PacketFormatterAdapter.DataConverter.CreateConnAckPacket(validatorContext);
await channelAdapter.SendPacketAsync(connAckPacket, _options.DefaultCommunicationTimeout, cancellationToken).ConfigureAwait(false);
return;
}
var connection = await CreateConnectionAsync(channelAdapter, connectPacket).ConfigureAwait(false);
await _eventDispatcher.HandleClientConnectedAsync(clientId).ConfigureAwait(false);
disconnectType = await connection.RunAsync().ConfigureAwait(false);
}
catch (OperationCanceledException)
{
}
catch (Exception exception)
{
_logger.Error(exception, exception.Message);
}
finally
{
if (clientId != null)
{
_connections.TryRemove(clientId, out _);
if (!_options.EnablePersistentSessions)
{
await DeleteSessionAsync(clientId).ConfigureAwait(false);
}
}
await TryCleanupChannelAsync(channelAdapter).ConfigureAwait(false);
if (clientId != null)
{
await _eventDispatcher.TryHandleClientDisconnectedAsync(clientId, disconnectType).ConfigureAwait(false);
}
}
}
public async Task <bool> RunAsync(MqttConnectPacket connectPacket, IMqttChannelAdapter adapter)
{
if (connectPacket == null)
{
throw new ArgumentNullException(nameof(connectPacket));
}
if (adapter == null)
{
throw new ArgumentNullException(nameof(adapter));
}
try
{
_adapter = adapter;
adapter.ReadingPacketStarted += OnAdapterReadingPacketStarted;
adapter.ReadingPacketCompleted += OnAdapterReadingPacketCompleted;
_cancellationTokenSource = new CancellationTokenSource();
_wasCleanDisconnect = false;
_willMessage = connectPacket.WillMessage;
_pendingPacketsQueue.Start(adapter, _cancellationTokenSource.Token);
_keepAliveMonitor.Start(connectPacket.KeepAlivePeriod, _cancellationTokenSource.Token);
while (!_cancellationTokenSource.IsCancellationRequested)
{
var packet = await adapter.ReceivePacketAsync(TimeSpan.Zero, _cancellationTokenSource.Token).ConfigureAwait(false);
if (packet != null)
{
_keepAliveMonitor.PacketReceived(packet);
ProcessReceivedPacket(adapter, packet, _cancellationTokenSource.Token);
}
}
}
catch (OperationCanceledException)
{
}
catch (Exception exception)
{
if (exception is MqttCommunicationException)
{
if (exception is MqttCommunicationClosedGracefullyException)
{
_logger.Verbose("Client '{0}': Connection closed gracefully.", ClientId);
}
else
{
_logger.Warning(exception, "Client '{0}': Communication exception while receiving client packets.", ClientId);
}
}
else
{
_logger.Error(exception, "Client '{0}': Unhandled exception while receiving client packets.", ClientId);
}
Stop(MqttClientDisconnectType.NotClean);
}
finally
{
if (_adapter != null)
{
_adapter.ReadingPacketStarted -= OnAdapterReadingPacketStarted;
_adapter.ReadingPacketCompleted -= OnAdapterReadingPacketCompleted;
}
_adapter = null;
_cancellationTokenSource?.Dispose();
_cancellationTokenSource = null;
}
return(_wasCleanDisconnect);
}