internal async Task <SocketError> SendDatagramAsync(UdpConnection connection, Datagram datagram)
{
if (connection == null)
{
throw new ArgumentNullException(nameof(connection));
}
if (datagram == null)
{
throw new ArgumentNullException(nameof(datagram));
}
if (datagram.IsDisposed)
{
Logger.Error("Got disposed datagram on Send. Perhaps race condition");
return(SocketError.InvalidArgument);
}
if (configuration.ConnectionSimulation != null)
{
if (random.NextDouble() < configuration.ConnectionSimulation.PacketLoss)
{
Logger.Debug($"We're sending datadram to {connection.EndPoint.EndPoint}, but according to connection simulation rules we dropped it");
return(SocketError.Success);
}
int delay = configuration.ConnectionSimulation.GetHalfDelay();
if (delay > 0)
{
await Task.Delay(delay).ConfigureAwait(false);
}
}
SendDatagramAsyncResult operationInfo = new SendDatagramAsyncResult(connection, datagram);
SocketAsyncEventArgs arg = socketArgsPool.Pop();
int bytes = datagram.WriteTo(new ArraySegment <byte>(arg.Buffer, 0, arg.Buffer.Length));
arg.SetBuffer(arg.Buffer, 0, bytes);
arg.RemoteEndPoint = connection.EndPoint.EndPoint;
arg.UserToken = operationInfo;
Logger.Debug($"Sending {datagram} to {arg.RemoteEndPoint}");
if (!socket.SendToAsync(arg))
{
IO_Complete(this, arg);
}
return(await operationInfo.Task.ConfigureAwait(false));
}
void EndSend(SocketAsyncEventArgs e)
{
try
{
SendDatagramAsyncResult opInfo = (SendDatagramAsyncResult)e.UserToken;
if (e.SocketError != SocketError.Success)
{
switch (e.SocketError)
{
case SocketError.WouldBlock:
// send buffer full?
// LogWarning("Socket threw exception; would block - send buffer full? Increase in NetPeerConfiguration");
Logger.Error("Send error SocketError.WouldBlock: probably buffer is full");
break;
case SocketError.ConnectionReset:
Logger.Debug($"Remote peer responded with connection reset");
(e.UserToken as UdpConnection).CloseImmidiately(DisconnectReason.ClosedByOtherPeer);
// connection reset by peer, aka connection forcibly closed aka "ICMP port unreachable"
break;
default:
Logger.Error($"Sending {opInfo.Datagram} failed: {e.SocketError}");
break;
}
}
opInfo.SetComplete(e.SocketError);
if (!opInfo.Datagram.DontDisposeOnSend)
{
opInfo.Datagram.Dispose();
}
}
finally
{
e.UserToken = null;
}
}