private void TcpReceiveLengthCompleted <TMessage>(IAsyncResult ar)
where TMessage : DnsMessageBase, new()
{
DnsClientAsyncState <TMessage> state = (DnsClientAsyncState <TMessage>)ar.AsyncState;
if (state.Timer != null)
{
state.Timer.Dispose();
}
if (state.TimedOut)
{
state.EndpointInfoIndex++;
TcpBeginConnect(state);
}
else
{
try
{
state.TcpBytesToReceive -= state.TcpStream.EndRead(ar);
if (state.TcpBytesToReceive > 0)
{
IAsyncResult asyncResult = state.TcpStream.BeginRead(state.Buffer, 2 - state.TcpBytesToReceive, state.TcpBytesToReceive, TcpReceiveLengthCompleted <TMessage>, state);
state.Timer = new Timer(TcpTimedOut <TMessage>, asyncResult, state.TimeRemaining, Timeout.Infinite);
}
else
{
int tmp = 0;
int responseLength = DnsMessageBase.ParseUShort(state.Buffer, ref tmp);
state.Buffer = new byte[responseLength];
state.TcpBytesToReceive = responseLength;
IAsyncResult asyncResult = state.TcpStream.BeginRead(state.Buffer, 0, responseLength, TcpReceiveCompleted <TMessage>, state);
state.Timer = new Timer(TcpTimedOut <TMessage>, asyncResult, state.TimeRemaining, Timeout.Infinite);
}
}
catch (Exception e)
{
Trace.TraceError("Error on dns query: " + e);
try
{
state.TcpClient.Close();
state.Timer.Dispose();
}
catch { }
state.EndpointInfoIndex++;
TcpBeginConnect(state);
}
}
}
private byte[] QueryByTcp(IPAddress nameServer, byte[] messageData, int messageLength, ref TcpClient tcpClient, ref NetworkStream tcpStream, out IPAddress responderAddress)
{
responderAddress = nameServer;
IPEndPoint endPoint = new IPEndPoint(nameServer, _port);
try
{
if (tcpClient == null)
{
tcpClient = new TcpClient(nameServer.AddressFamily)
{
ReceiveTimeout = QueryTimeout,
SendTimeout = QueryTimeout
};
tcpClient.Connect(endPoint);
tcpStream = tcpClient.GetStream();
}
int tmp = 0;
byte[] lengthBuffer = new byte[2];
if (messageLength > 0)
{
DnsMessageBase.EncodeUShort(lengthBuffer, ref tmp, (ushort)messageLength);
tcpStream.Write(lengthBuffer, 0, 2);
tcpStream.Write(messageData, 0, messageLength);
}
lengthBuffer[0] = (byte)tcpStream.ReadByte();
lengthBuffer[1] = (byte)tcpStream.ReadByte();
tmp = 0;
int length = DnsMessageBase.ParseUShort(lengthBuffer, ref tmp);
byte[] resultData = new byte[length];
int readBytes = 0;
while (readBytes < length)
{
readBytes += tcpStream.Read(resultData, readBytes, length - readBytes);
}
return(resultData);
}
catch (Exception e)
{
Trace.TraceError("Error on dns query: " + e);
return(null);
}
}
private void EndTcpReadLength(IAsyncResult ar)
{
TcpClient client = null;
NetworkStream stream = null;
try
{
MyState state = (MyState)ar.AsyncState;
client = state.Client;
stream = state.Stream;
state.Timer.Dispose();
state.BytesToReceive -= stream.EndRead(ar);
if (state.BytesToReceive > 0)
{
if (!IsTcpClientConnected(client))
{
HandleTcpException(null, stream, client);
return;
}
state.Timer = new Timer(TcpTimedOut, state, state.TimeRemaining, System.Threading.Timeout.Infinite);
state.AsyncResult = stream.BeginRead(state.Buffer, state.Buffer.Length - state.BytesToReceive, state.BytesToReceive, EndTcpReadLength, state);
}
else
{
int tmp = 0;
int length = DnsMessageBase.ParseUShort(state.Buffer, ref tmp);
if (length > 0)
{
state.Buffer = new byte[length];
state.Timer = new Timer(TcpTimedOut, state, state.TimeRemaining, System.Threading.Timeout.Infinite);
state.AsyncResult = stream.BeginRead(state.Buffer, 0, length, EndTcpReadData, state);
}
else
{
HandleTcpException(null, stream, client);
}
}
}
catch (Exception e)
{
HandleTcpException(e, stream, client);
}
}
