public CoapDtlsServerClientEndPoint(IPEndPoint endPoint, QueueDatagramTransport udpTransport, DateTime sessionStartTime)
{
BaseUri = new UriBuilder()
{
Scheme = "coaps://",
Host = endPoint.Address.ToString(),
Port = endPoint.Port
}.Uri;
EndPoint = endPoint;
_udpTransport = udpTransport;
SessionStartTime = sessionStartTime;
}
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");
}
}
}
