/// <summary>
/// Invoke when a datagram is received from a socket.
/// </summary>
/// <param name="receive"></param>
/// <param name="respond"></param>
/// <param name="args"></param>
public void OnReceive(Socket receive, Socket respond, SocketAsyncEventArgs args)
{
var source = new KIpEndpoint((IPEndPoint)args.RemoteEndPoint);
logger.LogTrace("Received incoming packet of {Length} from {Endpoint}.", args.BytesTransferred, source);
try
{
// no data found
if (args.BytesTransferred == 0)
{
return;
}
// some error occurred?
if (args.SocketError != SocketError.Success)
{
logger.LogError("Socket error while receiving UDP data: {SocketError}.", args.SocketError);
return;
}
// we only care about receive from events
if (args.LastOperation != SocketAsyncOperation.ReceiveFrom &&
args.LastOperation != SocketAsyncOperation.ReceiveMessageFrom)
{
logger.LogError("Unxpected operation while receiving UDP data: {LastOperation}.", args.LastOperation);
return;
}
// deserialize message sequence
var packet = serializer.Read(new ReadOnlyMemory <byte>(args.Buffer, args.Offset, args.BytesTransferred), new KMessageContext <TNodeId>(formats.Select(i => i.ContentType)));
if (packet.Format == null || packet.Sequence == null)
{
logger.LogWarning("Invalid or empty packet.");
return;
}
Task.Run(async() =>
{
try
{
logger.LogTrace("Decoded packet as {Format} from {Endpoint}.", packet.Format, source);
await OnReceiveAsync(receive, respond, source, packet, CancellationToken.None);
}
catch (Exception e)
{
logger.LogError(e, "Unhandled exception receiving UDP packet.");
}
});
}
catch (Exception e)
{
logger.LogError(e, "Exception during UDP receive.");
}
}
/// <summary>
/// Invoked when a receive operation completes.
/// </summary>
/// <param name="socket"></param>
/// <param name="args"></param>
void RecvArgs_Completed(Socket socket, SocketAsyncEventArgs args)
{
// extract source endpoint
var source = new KIpEndpoint((IPEndPoint)args.RemoteEndPoint);
var length = args.BytesTransferred;
logger.LogTrace("Received incoming UDP packet of {Length} from {Endpoint}.", length, source);
// should only be receiving packets from our message loop
if (args.LastOperation != SocketAsyncOperation.ReceiveMessageFrom)
{
logger.LogTrace("Unexpected packet operation {Operation}.", args.LastOperation);
return;
}
// some error occurred?
if (args.SocketError != SocketError.Success)
{
return;
}
// we only care about receive from events
if (args.LastOperation != SocketAsyncOperation.ReceiveMessageFrom &&
args.LastOperation != SocketAsyncOperation.ReceiveFrom)
{
return;
}
// no data found
if (args.BytesTransferred == 0)
{
return;
}
// socket is unbound, ignore
if (socket.IsBound == false)
{
return;
}
// deserialize message sequence
var packet = serializer.Read(new ReadOnlyMemory <byte>(args.Buffer, args.Offset, args.BytesTransferred), new KMessageContext <TNodeId>(formats.Select(i => i.ContentType)));
if (packet.Format == null || packet.Sequence == null)
{
return;
}
Task.Run(async() =>
{
try
{
logger.LogTrace("Decoded packet as {Format} from {Endpoint}.", packet.Format, source);
await OnReceiveAsync(socket, source, packet, CancellationToken.None);
}
catch (Exception e)
{
logger.LogError(e, "Unhandled exception dispatching incoming packet.");
}
});
// continue receiving if socket still available
// this lock is blocking, but should be okay since this event handler can stall
using (sync.LockAsync().GetAwaiter().GetResult())
{
// reset remote endpoint
args.RemoteEndPoint = source.Protocol switch
{
KIpAddressFamily.IPv4 => new IPEndPoint(IPAddress.Any, 0),
KIpAddressFamily.IPv6 => new IPEndPoint(IPAddress.IPv6Any, 0),
_ => throw new InvalidOperationException(),
};
try
{
socket.ReceiveMessageFromAsync(args);
}
catch (ObjectDisposedException)
{
// we must have been terminated, ignore
}
}
}
