public static SocketAwaitable ReceiveMessageFromAsync(this Socket socket,
SocketAwaitable awaitable)
{
awaitable.Reset();
if (!socket.ReceiveMessageFromAsync(awaitable.m_eventArgs))
{
awaitable.m_wasCompleted = true;
}
return(awaitable);
}
public static SocketAwaitable SendToAsync(this Socket socket,
SocketAwaitable awaitable)
{
awaitable.Reset();
if (!socket.SendToAsync(awaitable.m_eventArgs))
{
awaitable.m_wasCompleted = true;
}
return(awaitable);
}
/// <summary>
/// Sends a response message.
/// </summary>
/// <param name="response">
/// A <see cref="ISnmpMessage"/>.
/// </param>
/// <param name="receiver">Receiver.</param>
public async Task SendResponseAsync(ISnmpMessage response, EndPoint receiver)
{
if (_disposed)
{
throw new ObjectDisposedException(GetType().FullName);
}
if (response == null)
{
throw new ArgumentNullException(nameof(response));
}
if (receiver == null)
{
throw new ArgumentNullException(nameof(receiver));
}
if (_disposed)
{
throw new ObjectDisposedException("Listener");
}
if (_socket == null)
{
return;
}
var buffer = response.ToBytes();
var info = SocketExtension.EventArgsFactory.Create();
try
{
info.RemoteEndPoint = receiver;
info.SetBuffer(buffer, 0, buffer.Length);
using (var awaitable1 = new SocketAwaitable(info))
{
await _socket.SendToAsync(awaitable1);
}
}
catch (SocketException ex)
{
if (ex.SocketErrorCode != SocketError.Interrupted)
{
// IMPORTANT: interrupted means the socket is closed.
throw;
}
}
}
private async Task ReceiveAsync()
{
while (true)
{
// If no more active, then stop.
if (Interlocked.Exchange(ref _active, _active) == Inactive)
{
return;
}
int count;
var reply = new byte[_bufferSize];
var args = SocketExtension.EventArgsFactory.Create();
try
{
EndPoint remote = _socket.AddressFamily == AddressFamily.InterNetwork ? new IPEndPoint(IPAddress.Any, 0) : new IPEndPoint(IPAddress.IPv6Any, 0);
args.RemoteEndPoint = remote;
args.SetBuffer(reply, 0, _bufferSize);
using (var awaitable = new SocketAwaitable(args))
{
count = await _socket.ReceiveMessageFromAsync(awaitable);
}
await Task.Factory.StartNew(() => HandleMessage(reply, count, (IPEndPoint)args.RemoteEndPoint));
}
catch (SocketException ex)
{
// ignore WSAECONNRESET, http://bytes.com/topic/c-sharp/answers/237558-strange-udp-socket-problem
if (ex.SocketErrorCode != SocketError.ConnectionReset)
{
// If the SnmpTrapListener was active, marks it as stopped and call HandleException.
// If it was inactive, the exception is likely to result from this, and we raise nothing.
var activeBefore = Interlocked.CompareExchange(ref _active, Inactive, Active);
if (activeBefore == Active)
{
HandleException(ex);
}
}
}
}
}
