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 TcpConnectCompleted <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.TcpClient.EndConnect(ar);
state.TcpStream = state.TcpClient.GetStream();
int tmp = 0;
state.Buffer = new byte[2];
DnsMessageBase.EncodeUShort(state.Buffer, ref tmp, (ushort)state.QueryLength);
IAsyncResult asyncResult = state.TcpStream.BeginWrite(state.Buffer, 0, 2, TcpSendLengthCompleted <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);
}
}
}
internal void Encode(byte[] messageData, int offset, ref int currentPosition, Dictionary <string, ushort> domainNames)
{
DnsMessageBase.EncodeDomainName(messageData, offset, ref currentPosition, Name, true, domainNames);
DnsMessageBase.EncodeUShort(messageData, ref currentPosition, (ushort)RecordType);
DnsMessageBase.EncodeUShort(messageData, ref currentPosition, (ushort)RecordClass);
}