/// <summary>
/// Begin listening for incoming connections. Once this is called, you must call Close before calling Listen again.
/// </summary>
/// <param name="localEndpoint">The local endpoint to listen on.</param>
public void Listen(IPEndPoint localEndpoint, bool discoverable = true, string name = "SimplSocketServer", string description = null)
{
// Sanitize
if (localEndpoint == null)
{
throw new ArgumentNullException(nameof(localEndpoint));
}
lock (_isListeningLock)
{
if (_isListening)
{
throw new InvalidOperationException("socket is already in use");
}
_isListening = true;
}
// Create socket
_socket = _socketFunc();
_socket.Bind(localEndpoint);
_socket.Listen(PredictedConnectionCount);
// very important to not have buffer for accept, see remarks on 288 byte threshold: https://msdn.microsoft.com/en-us/library/system.net.sockets.socket.acceptasync(v=vs.110).aspx
var socketAsyncEventArgs = new SocketAsyncEventArgs();
socketAsyncEventArgs.Completed += OperationCallback;
// Post accept on the listening socket
if (!TryUnsafeSocketOperation(_socket, SocketAsyncOperation.Accept, socketAsyncEventArgs))
{
lock (_isListeningLock)
{
_isListening = false;
throw new Exception("Socket accept failed");
}
}
// Spin up the keep-alive
Task.Factory.StartNew(KeepAlive);
// Start beacon if discoverable
_beacon = new Beacon(name, (ushort)localEndpoint.Port);
_beacon.BeaconData = description ?? $"name {Dns.GetHostName()} ";
_beacon.StartAsync();
//_beacon.Start();
}
private async Task BroadcastProbeAsync()
{
Debug.WriteLine($"P: Broadcasting probe with discovery port {Beacon.DiscoveryPort}");
var probe = Beacon.Encode(BeaconType).ToArray();
await udp.SendAsync(probe, probe.Length, new IPEndPoint(IPAddress.Broadcast, Beacon.DiscoveryPort));
}
