public async Task <IDnsResponse> Resolve(IDnsRequest request)
{
using (UdpClient udp = new UdpClient())
{
await udp
.SendAsync(request.ToArray(), request.Size, dns)
.WithCancellationTimeout(timeout);
UdpReceiveResult result = await udp.ReceiveAsync().WithCancellationTimeout(timeout);
if (!result.RemoteEndPoint.Equals(dns))
{
throw new IOException("Remote endpoint mismatch");
}
byte[] buffer = result.Buffer;
DefaultDnsResponse response = DefaultDnsResponse.FromArray(buffer);
if (response.Truncated)
{
return(await fallback.Resolve(request));
}
return(new ClientDnsResponse(request, response, buffer));
}
}
public async Task <IDnsResponse> Resolve(IDnsRequest request)
{
using (TcpClient tcp = new TcpClient())
{
await tcp.ConnectAsync(dns.Address, dns.Port);
Stream stream = tcp.GetStream();
byte[] buffer = request.ToArray();
byte[] length = BitConverter.GetBytes((ushort)buffer.Length);
if (BitConverter.IsLittleEndian)
{
Array.Reverse(length);
}
await stream.WriteAsync(length, 0, length.Length);
await stream.WriteAsync(buffer, 0, buffer.Length);
buffer = new byte[2];
await Read(stream, buffer);
if (BitConverter.IsLittleEndian)
{
Array.Reverse(buffer);
}
buffer = new byte[BitConverter.ToUInt16(buffer, 0)];
await Read(stream, buffer);
IDnsResponse response = DefaultDnsResponse.FromArray(buffer);
return(new ClientDnsResponse(request, response, buffer));
}
}
public Task <IDnsResponse> Resolve(IDnsRequest request)
{
IDnsResponse response = DefaultDnsResponse.FromRequest(request);
foreach (DnsQuestion question in request.Questions)
{
IList <IResourceRecord> answers = Get(question);
if (answers.Count > 0)
{
Merge(response.AnswerRecords, answers);
}
else
{
response.ResponseCode = DnsResponseCode.NameError;
}
}
return(Task.FromResult(response));
}
private async void HandleRequest(byte[] data, IPEndPoint remote)
{
DefaultDnsRequest request = null;
try
{
request = DefaultDnsRequest.FromArray(data);
OnRequested(request);
IDnsResponse response = await resolver.Resolve(request);
OnResponded(request, response);
await udp
.SendAsync(response.ToArray(), response.Size, remote)
.WithCancellationTimeout(UDP_TIMEOUT);
}
catch (SocketException e)
{
OnErrored(e);
}
catch (ArgumentException e)
{
OnErrored(e);
}
catch (IndexOutOfRangeException e)
{
OnErrored(e);
}
catch (OperationCanceledException e)
{
OnErrored(e);
}
catch (IOException e)
{
OnErrored(e);
}
catch (ObjectDisposedException e)
{
OnErrored(e);
}
catch (DnsResponseException e)
{
IDnsResponse response = e.DnsResponse;
if (response == null)
{
response = DefaultDnsResponse.FromRequest(request);
}
try
{
await udp
.SendAsync(response.ToArray(), response.Size, remote)
.WithCancellationTimeout(UDP_TIMEOUT);
}
catch (SocketException)
{
}
catch (OperationCanceledException)
{
}
finally
{
OnErrored(e);
}
}
}
public static ClientDnsResponse FromArray(IDnsRequest request, byte[] message)
{
DefaultDnsResponse response = DefaultDnsResponse.FromArray(message);
return(new ClientDnsResponse(request, response, message));
}
