/// <summary>
/// Thread procedure that is responsible for accepting new clients on the TCP server port.
/// New clients are put into clientQueue, from which they are consumed by clientQueueHandlerThread.
/// </summary>
private void AcceptThread()
{
LogDiagnosticContext.Start();
log.Trace("()");
acceptThreadFinished.Reset();
AutoResetEvent acceptTaskEvent = new AutoResetEvent(false);
while (!ShutdownSignaling.IsShutdown)
{
log.Debug("Waiting for new client.");
Task <TcpClient> acceptTask = Listener.AcceptTcpClientAsync();
acceptTask.ContinueWith(t => acceptTaskEvent.Set());
WaitHandle[] handles = new WaitHandle[] { acceptTaskEvent, ShutdownSignaling.ShutdownEvent };
int index = WaitHandle.WaitAny(handles);
if (handles[index] == ShutdownSignaling.ShutdownEvent)
{
log.Info("Shutdown detected.");
break;
}
try
{
// acceptTask is finished here, asking for Result won't block.
TcpClient client = acceptTask.Result;
EndPoint ep = client.Client.RemoteEndPoint;
lock (clientQueueLock)
{
clientQueue.Enqueue(client);
}
log.Debug("New client '{0}' accepted.", ep);
clientQueueEvent.Set();
}
catch (Exception e)
{
log.Error("Exception occurred: {0}", e.ToString());
}
}
acceptThreadFinished.Set();
log.Trace("(-)");
LogDiagnosticContext.Stop();
}
/// <summary>
/// Connects to a specific IP address and port and initializes stream.
/// If TLS is used, client authentication is done as well.
/// </summary>
/// <returns>true if the connection was established succcessfully, false otherwise.</returns>
public async Task <bool> ConnectAsync()
{
log.Trace("()");
bool res = false;
try
{
await TcpClient.ConnectAsync(remoteEndPoint.Address, remoteEndPoint.Port);
stream = TcpClient.GetStream();
if (UseTls)
{
SslStream sslStream = new SslStream(stream, false, PeerCertificateValidationCallback);
await sslStream.AuthenticateAsClientAsync("", null, SslProtocols.Tls12, false);
stream = sslStream;
}
res = true;
}
catch (Exception e)
{
log.Debug("Unable to connect to {0}, error exception: {1}", remoteEndPoint, e.ToString());
}
log.Trace("(-):{0}", res);
return(res);
}
/// <summary>
/// Thread procedure that consumes clients from clientQueue.
/// When a new client is detected in the queue, it is removed from the queue
/// and enters asynchronous read and processing loop.
/// </summary>
private void ClientQueueHandlerThread()
{
log.Info("()");
clientQueueHandlerThreadFinished.Reset();
while (!ShutdownSignaling.IsShutdown)
{
WaitHandle[] handles = new WaitHandle[] { clientQueueEvent, ShutdownSignaling.ShutdownEvent };
int index = WaitHandle.WaitAny(handles);
if (handles[index] == ShutdownSignaling.ShutdownEvent)
{
log.Info("Shutdown detected.");
break;
}
log.Debug("New client in the queue detected, queue count is {0}.", clientQueue.Count);
bool queueEmpty = false;
while (!queueEmpty && !ShutdownSignaling.IsShutdown)
{
TcpClient tcpClient = null;
lock (clientQueueLock)
{
if (clientQueue.Count > 0)
{
tcpClient = clientQueue.Peek();
}
}
if (tcpClient != null)
{
int keepAliveInterval = IsServingClientsOnly ? ClientKeepAliveIntervalSeconds : NodeKeepAliveIntervalSeconds;
Client client = new Client(this, tcpClient, clientList.GetNewClientId(), UseTls, keepAliveInterval);
ClientHandlerAsync(client);
lock (clientQueueLock)
{
clientQueue.Dequeue();
queueEmpty = clientQueue.Count == 0;
}
}
else
{
queueEmpty = true;
}
}
}
clientQueueHandlerThreadFinished.Set();
log.Info("(-)");
}
/// <summary>
/// Asynchronous read and processing function for each client that connects to the TCP server.
/// </summary>
/// <param name="Client">Client that is connected to TCP server.</param>
/// <remarks>The client is being handled in the processing loop until the connection to it
/// is terminated by either side. This function implements reading the message from the network stream,
/// which includes reading the message length prefix followed by the entire message.</remarks>
private async void ClientHandlerAsync(Client Client)
{
this.log.Info("(Client.RemoteEndPoint:{0})", Client.RemoteEndPoint);
string prefix = string.Format("{0}[{1}] ", this.logPrefix, Client.RemoteEndPoint);
PrefixLogger log = new PrefixLogger(this.logName, prefix);
clientList.AddNetworkPeer(Client);
log.Debug("Client ID set to 0x{0:X16}.", Client.Id);
await Client.ReceiveMessageLoop();
// Free resources used by the client.
clientList.RemoveNetworkPeer(Client);
await Client.HandleDisconnect();
Client.Dispose();
log.Info("(-)");
}
/// <summary>
/// Callback routine that is called once the timeoutTimer expires.
/// <para>
/// If relay status is WaitingForCalleeResponse, the callee has to reply to the incoming call notification
/// within a reasonable time. If it does the timer is cancelled. If it does not, the timeout occurs.
/// </para>
/// <para>
/// If relay status is WaitingForFirstInitMessage, both clients are expected to connect to clAppService port
/// and send an initial message over that service. The timeoutTimer expires when none of the clients
/// connects to clAppService port and sends its initialization message within a reasonable time.
/// </para>
/// <para>
/// Then if relay status is WaitingForSecondInitMessage, the node receives a message from the first client
/// on clAppService port, it starts the timer again, which now expires if the second client does not connect
/// and send its initial message within a reasonable time.
/// </para>
/// </summary>
/// <param name="state">Status of the relay when the timer was installed.</param>
private async void TimeoutCallback(object State)
{
RelayConnectionStatus previousStatus = (RelayConnectionStatus)State;
log.Trace("(State:{0})", previousStatus);
Client clientToSendMessage = null;
Message messageToSend = null;
bool destroyRelay = false;
await lockObject.WaitAsync();
if (timeoutTimer != null)
{
switch (status)
{
case RelayConnectionStatus.WaitingForCalleeResponse:
{
// The caller requested the call and the callee was notified.
// The callee failed to send us response on time, this is situation 2)
// from ProcessMessageCallIdentityApplicationServiceRequestAsync.
// We send ERROR_NOT_AVAILABLE to the caller and destroy the relay.
log.Debug("Callee failed to reply to the incoming call notification, closing relay.");
clientToSendMessage = caller;
messageToSend = caller.MessageBuilder.CreateErrorNotAvailableResponse(pendingMessage);
break;
}
case RelayConnectionStatus.WaitingForFirstInitMessage:
{
// Neither client joined the channel on time, nothing to do, just destroy the relay.
log.Debug("None of the clients joined the relay on time, closing relay.");
break;
}
case RelayConnectionStatus.WaitingForSecondInitMessage:
{
// One client is waiting for the other one to join, but the other client failed to join on time.
// We send ERROR_NOT_FOUND to the waiting client and close its connection.
log.Debug("{0} failed to join the relay on time, closing relay.", callee != null ? "Caller" : "Callee");
clientToSendMessage = callee != null ? callee : caller;
messageToSend = clientToSendMessage.MessageBuilder.CreateErrorNotFoundResponse(pendingMessage);
break;
}
default:
log.Debug("Time out triggered while the relay status was {0}.", status);
break;
}
// In case of any timeouts, we just destroy the relay.
destroyRelay = true;
}
else
{
log.Debug("Timeout timer of relay '{0}' has been destroyed, no action taken.", id);
}
lockObject.Release();
if (messageToSend != null)
{
if (!await clientToSendMessage.SendMessageAsync(messageToSend))
{
log.Warn("Unable to send message to the client ID '0x{0:X16}' in relay '{1}', maybe it is not connected anymore.", clientToSendMessage.Id, id);
}
}
if (destroyRelay)
{
Server serverComponent = (Server)Base.ComponentDictionary["Network.Server"];
ClientList clientList = serverComponent.GetClientList();
await clientList.DestroyNetworkRelay(this);
}
log.Trace("(-)");
}