private async Task HandleIncoming()
{
while (!_cts.IsCancellationRequested)
{
try
{
UdpReceiveResult data;
try
{
data = await _socket.ReceiveAsync();
_logger.LogDebug("Received DTLS Packet from {EndPoint}", data.RemoteEndPoint);
}
catch (ObjectDisposedException)
{
// Happens when the Connection is being closed
continue;
}
catch (SocketException sockEx)
{
// Some clients send an ICMP Port Unreachable when they receive data after they stopped listening.
// If we knew from which client it came we could get rid of the connection, but we can't, so we just ignore the exception.
if (sockEx.SocketErrorCode == SocketError.ConnectionReset)
{
_logger.LogInformation("Connection Closed by remote host");
continue;
}
_logger.LogError("SocketException with SocketErrorCode {SocketErrorCode}", sockEx.SocketErrorCode);
throw;
}
// if there is an existing session, we pass the datagram to the session.
if (_sessions.TryGetValue(data.RemoteEndPoint, out CoapDtlsServerClientEndPoint session))
{
session.EnqueueDatagram(data.Buffer);
continue;
}
// if there isn't an existing session for this remote endpoint, we start a new one and pass the first datagram to the session
var transport = new QueueDatagramTransport(NetworkMtu, bytes => _sendQueue.Add(new UdpSendPacket(bytes, data.RemoteEndPoint)));
session = new CoapDtlsServerClientEndPoint(data.RemoteEndPoint, transport, DateTime.UtcNow);
session.EnqueueDatagram(data.Buffer);
_sessions.TryAdd(data.RemoteEndPoint, session);
try
{
_logger.LogInformation("New connection from {EndPoint}; Active Sessions: {ActiveSessions}", data.RemoteEndPoint, _sessions.Count);
#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
Task.Factory.StartNew(() => HandleSession(session), TaskCreationOptions.LongRunning);
#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
}
catch (Exception ex)
{
_logger.LogError(ex, "Exception while starting session handler!");
_sessions.TryRemove(session.EndPoint, out _);
}
}
catch (Exception ex)
{
_logger.LogError(ex, "Error while handling incoming datagrams");
}
}
}
private async Task HandleSession(CoapDtlsServerClientEndPoint session)
{
var state = new Dictionary <string, object>
{
{ "RemoteEndPoint", session?.EndPoint }
};
using (_logger.BeginScope(state))
{
try
{
_logger.LogDebug("Trying to accept TLS connection from {EndPoint}", session.EndPoint);
var server = _tlsServerFactory.Create();
session.Accept(_serverProtocol, server);
if (session.ConnectionInfo != null)
{
_logger.LogInformation("New TLS connection from {EndPoint}, Server Info: {ServerInfo}", session.EndPoint, session.ConnectionInfo);
}
else
{
_logger.LogInformation("New TLS connection from {EndPoint}", session.EndPoint);
}
var connectionInfo = new CoapDtlsConnectionInformation
{
LocalEndpoint = _endPoint,
RemoteEndpoint = session,
TlsServer = server
};
while (!session.IsClosed && !_cts.IsCancellationRequested)
{
var packet = await session.ReceiveAsync(_cts.Token);
_logger.LogDebug("Handling CoAP Packet from {EndPoint}", session.EndPoint);
await _coapHandler.ProcessRequestAsync(connectionInfo, packet.Payload);
_logger.LogDebug("CoAP request from {EndPoint} handled!", session.EndPoint);
}
}
catch (OperationCanceledException)
{
}
catch (DtlsConnectionClosedException)
{
}
catch (TlsFatalAlert tlsAlert)
{
if (!(tlsAlert.InnerException is DtlsConnectionClosedException) && tlsAlert.AlertDescription != AlertDescription.user_canceled)
{
_logger.LogWarning(tlsAlert, "TLS Error");
}
}
catch (Exception ex)
{
_logger.LogError(ex, "Error while handling session");
}
finally
{
_logger.LogInformation("Connection from {EndPoint} closed", session.EndPoint);
_sessions.TryRemove(session.EndPoint, out _);
}
}
}