private void ProcessTcpRequestAsync(object parameter)
{
Socket tcpSocket = parameter as Socket;
DnsDatagram request = null;
try
{
NetworkStream recvStream = new NetworkStream(tcpSocket);
OffsetStream recvDatagramStream = new OffsetStream(recvStream, 0, 0);
MemoryStream sendBufferStream = null;
byte[] sendBuffer = null;
ushort length;
while (true)
{
//read dns datagram length
{
byte[] lengthBuffer = recvStream.ReadBytes(2);
Array.Reverse(lengthBuffer, 0, 2);
length = BitConverter.ToUInt16(lengthBuffer, 0);
}
//read dns datagram
recvDatagramStream.Reset(0, length, 0);
request = new DnsDatagram(recvDatagramStream);
DnsDatagram response = ProcessQuery(request, tcpSocket.RemoteEndPoint);
//send response
if (response != null)
{
if (sendBufferStream == null)
{
sendBufferStream = new MemoryStream(64);
}
//write dns datagram
sendBufferStream.Position = 0;
response.WriteTo(sendBufferStream);
//prepare final buffer
length = Convert.ToUInt16(sendBufferStream.Position);
if ((sendBuffer == null) || (sendBuffer.Length < length + 2))
{
sendBuffer = new byte[length + 2];
}
//copy datagram length
byte[] lengthBuffer = BitConverter.GetBytes(length);
sendBuffer[0] = lengthBuffer[1];
sendBuffer[1] = lengthBuffer[0];
//copy datagram
sendBufferStream.Position = 0;
sendBufferStream.Read(sendBuffer, 2, length);
//send dns datagram
tcpSocket.Send(sendBuffer, 0, length + 2, SocketFlags.None);
LogManager queryLog = _queryLog;
if (queryLog != null)
{
queryLog.Write(tcpSocket.RemoteEndPoint as IPEndPoint, true, request, response);
}
StatsManager stats = _stats;
if (stats != null)
{
stats.Update(response, (tcpSocket.RemoteEndPoint as IPEndPoint).Address);
}
}
}
}
catch (IOException)
{
//ignore IO exceptions
}
catch (Exception ex)
{
LogManager queryLog = _queryLog;
if ((queryLog != null) && (request != null))
{
queryLog.Write(tcpSocket.RemoteEndPoint as IPEndPoint, true, request, null);
}
LogManager log = _log;
if (log != null)
{
log.Write(tcpSocket.RemoteEndPoint as IPEndPoint, ex);
}
}
finally
{
if (tcpSocket != null)
{
tcpSocket.Dispose();
}
}
}
private void ProcessUdpRequestAsync(object parameter)
{
object[] parameters = parameter as object[];
EndPoint remoteEP = parameters[0] as EndPoint;
DnsDatagram request = parameters[1] as DnsDatagram;
try
{
DnsDatagram response = ProcessQuery(request, remoteEP);
//send response
if (response != null)
{
byte[] sendBuffer = new byte[512];
MemoryStream sendBufferStream = new MemoryStream(sendBuffer);
try
{
response.WriteTo(sendBufferStream);
}
catch (NotSupportedException)
{
DnsHeader header = response.Header;
response = new DnsDatagram(new DnsHeader(header.Identifier, true, header.OPCODE, header.AuthoritativeAnswer, true, header.RecursionDesired, header.RecursionAvailable, header.AuthenticData, header.CheckingDisabled, header.RCODE, header.QDCOUNT, 0, 0, 0), response.Question, null, null, null);
sendBufferStream.Position = 0;
response.WriteTo(sendBufferStream);
}
//send dns datagram
_udpListener.SendTo(sendBuffer, 0, (int)sendBufferStream.Position, SocketFlags.None, remoteEP);
LogManager queryLog = _queryLog;
if (queryLog != null)
{
queryLog.Write(remoteEP as IPEndPoint, false, request, response);
}
StatsManager stats = _stats;
if (stats != null)
{
stats.Update(response, (remoteEP as IPEndPoint).Address);
}
}
}
catch (Exception ex)
{
LogManager queryLog = _queryLog;
if (queryLog != null)
{
queryLog.Write(remoteEP as IPEndPoint, false, request, null);
}
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP as IPEndPoint, ex);
}
}
}
