private async void Respond(UdpReceiveResult query, CancellationToken token)
{
var stopwatch = Stopwatch.StartNew();
DnsHeader message;
try
{
message = DnsByteExtensions.FromBytes <DnsHeader>(query.Buffer);
}
catch (Exception e)
{
_logger.LogCritical(e, "Unable to parse incoming packet: {0}", DnsByteExtensions.ToDebugString(query.Buffer));
return;
}
DnsAnswer answer;
try
{
answer = await _dnsClient.Query(message, token);
}
catch (Exception e)
{
_logger.LogCritical(e, "Unable to resolve {0}", message);
return;
}
var answerBytes = DnsByteExtensions.ToBytes(answer).ToArray();
try
{
await _listener.SendAsync(answerBytes, answerBytes.Length, query.RemoteEndPoint);
}
catch (Exception e)
{
_logger.LogCritical(e, "Unable to send back response to {0}", query.RemoteEndPoint);
return;
}
_logger.LogTrace("Responded to DNS request for {Domain} in {ResponseTime}", message.Host, stopwatch.Elapsed.TotalSeconds);
}
private async Task ReceiveTask()
{
while (!_cancel.IsCancellationRequested)
{
UdpReceiveResult recieve;
try
{
recieve = await _socket.ReceiveAsync();
}
catch (ObjectDisposedException)
{
// Do nothing, client shutting down
return;
}
catch (Exception e)
{
_logger.LogCritical(e, "Received bad network response from {0}: {1}", recieve.RemoteEndPoint.ToString(), DnsByteExtensions.ToDebugString(recieve.Buffer));
continue;
}
if (recieve.Buffer.Length > 0)
{
_ = Task.Run(() => Receive(recieve.Buffer));
}
}
}
