protected TMessage SendMessage <TMessage>(TMessage message)
where TMessage : DnsMessageBase, new()
{
int messageLength;
byte[] messageData;
DnsServer.SelectTsigKey tsigKeySelector;
byte[] tsigOriginalMac;
PrepareMessage(message, out messageLength, out messageData, out tsigKeySelector, out tsigOriginalMac);
bool sendByTcp = ((messageLength > MaximumQueryMessageSize) || message.IsTcpUsingRequested || !IsUdpEnabled);
var endpointInfos = GetEndpointInfos();
for (int i = 0; i < endpointInfos.Count; i++)
{
var endpointInfo = endpointInfos[i];
TcpClient tcpClient = null;
System.IO.Stream tcpStream = null;
string reusableMapKey = string.Concat(endpointInfo.ServerAddress, endpointInfo.ServerPort);
if (sendByTcp && this.IsReuseTcpEnabled)
{
if (!this.reusableTcp.ContainsKey(reusableMapKey))
{
this.reusableTcp[reusableMapKey] = new ReusableTcpConnection();
}
ReusableTcpConnection reuse = this.reusableTcp[reusableMapKey];
tcpClient = reuse.Client;
tcpStream = reuse.Stream;
this.reusableTcp[reusableMapKey].LastUsed = DateTime.UtcNow;
}
try
{
IPAddress responderAddress;
int responderPort = 0;
byte[] resultData = sendByTcp ? QueryByTcp(endpointInfo.ServerAddress, endpointInfo.ServerPort, messageData, messageLength, ref tcpClient, ref tcpStream, out responderAddress, out responderPort) : QueryByUdp(endpointInfo, messageData, messageLength, out responderAddress);
if (resultData != null)
{
TMessage result;
try
{
result = DnsMessageBase.Parse <TMessage>(resultData, tsigKeySelector, tsigOriginalMac);
}
catch (Exception e)
{
Trace.TraceError("Error on dns query: " + e);
continue;
}
if (!ValidateResponse(message, result))
{
continue;
}
if ((result.ReturnCode == ReturnCode.ServerFailure) && (i != endpointInfos.Count - 1))
{
continue;
}
if (result.IsTcpResendingRequested)
{
resultData = QueryByTcp(responderAddress, responderPort, messageData, messageLength, ref tcpClient, ref tcpStream, out responderAddress, out responderPort);
if (resultData != null)
{
TMessage tcpResult;
try
{
tcpResult = DnsMessageBase.Parse <TMessage>(resultData, tsigKeySelector, tsigOriginalMac);
}
catch (Exception e)
{
Trace.TraceError("Error on dns query: " + e);
continue;
}
if (tcpResult.ReturnCode == ReturnCode.ServerFailure)
{
if (i != endpointInfos.Count - 1)
{
continue;
}
}
else
{
result = tcpResult;
}
}
}
bool isTcpNextMessageWaiting = result.IsTcpNextMessageWaiting(false);
bool isSucessfullFinished = true;
while (isTcpNextMessageWaiting)
{
resultData = QueryByTcp(responderAddress, responderPort, null, 0, ref tcpClient, ref tcpStream, out responderAddress, out responderPort);
if (resultData != null)
{
TMessage tcpResult;
try
{
tcpResult = DnsMessageBase.Parse <TMessage>(resultData, tsigKeySelector, tsigOriginalMac);
}
catch (Exception e)
{
Trace.TraceError("Error on dns query: " + e);
isSucessfullFinished = false;
break;
}
if (tcpResult.ReturnCode == ReturnCode.ServerFailure)
{
isSucessfullFinished = false;
break;
}
else
{
result.AnswerRecords.AddRange(tcpResult.AnswerRecords);
isTcpNextMessageWaiting = tcpResult.IsTcpNextMessageWaiting(true);
}
}
else
{
isSucessfullFinished = false;
break;
}
}
if (isSucessfullFinished)
{
return(result);
}
}
}
finally
{
try
{
if (sendByTcp && this.IsReuseTcpEnabled)
{
if (this.reusableTcp[reusableMapKey].Client == null || !ReferenceEquals(this.reusableTcp[reusableMapKey].Client, tcpClient))
{
this.reusableTcp[reusableMapKey].Client = tcpClient;
this.reusableTcp[reusableMapKey].Stream = tcpStream;
}
}
else
{
tcpStream?.Dispose();
tcpClient?.Close();
}
}
catch
{
// ignored
}
}
}
return(null);
}
protected virtual async Task <QueryResponse> QueryByTcpAsync(IPAddress nameServer, int port, byte[] messageData, int messageLength, TcpClient tcpClient, System.IO.Stream tcpStream, CancellationToken token)
{
if (!IsTcpEnabled)
{
return(null);
}
string reusableMapKey = string.Concat(nameServer, port);
if (tcpClient == null && this.IsReuseTcpEnabled)
{
if (!this.reusableTcp.ContainsKey(reusableMapKey))
{
this.reusableTcp[reusableMapKey] = new ReusableTcpConnection();
}
ReusableTcpConnection reuse = this.reusableTcp[reusableMapKey];
tcpClient = reuse.Client;
tcpStream = reuse.Stream;
this.reusableTcp[reusableMapKey].LastUsed = DateTime.UtcNow;
}
int responderPort = port == 0 ? _port : port;
try
{
if (tcpClient == null || (this.IsReuseTcpEnabled && !tcpClient.IsConnected()))
{
tcpClient = new TcpClient(nameServer.AddressFamily)
{
ReceiveTimeout = QueryTimeout,
SendTimeout = QueryTimeout
};
if (!await tcpClient.TryConnectAsync(nameServer, responderPort, QueryTimeout, token))
{
if (this.IsReuseTcpEnabled)
{
try
{
tcpClient.Close();
}
catch (Exception)
{
}
}
return(null);
}
tcpStream = tcpClient.GetStream();
}
int tmp = 0;
byte[] lengthBuffer = new byte[2];
if (messageLength > 0)
{
DnsMessageBase.EncodeUShort(lengthBuffer, ref tmp, (ushort)messageLength);
await tcpStream.WriteAsync(lengthBuffer, 0, 2, token);
await tcpStream.WriteAsync(messageData, 0, messageLength, token);
}
if (!await TryReadAsync(tcpClient, tcpStream, lengthBuffer, 2, token))
{
return(null);
}
tmp = 0;
int length = DnsMessageBase.ParseUShort(lengthBuffer, ref tmp);
byte[] resultData = new byte[length];
return(await TryReadAsync(tcpClient, tcpStream, resultData, length, token) ? new QueryResponse(resultData, nameServer, tcpClient, tcpStream, responderPort) : null);
}
catch (Exception e)
{
Trace.TraceError("Error on dns query: " + e);
return(null);
}
}
protected async override Task <QueryResponse> QueryByTcpAsync(IPAddress nameServer, int port, byte[] messageData, int messageLength, TcpClient tcpClient, System.IO.Stream tlsStream, CancellationToken token)
{
if (!IsTcpEnabled)
{
return(null);
}
int responderPort = port == 0 ? _port : port;
TlsUpstreamServer tlsServer = _tlsservers.Where(t => t.IPAddress == nameServer && t.Port == responderPort).FirstOrDefault();
if (tlsServer == null)
{
Trace.TraceError("Error on dns query: invalid TLS upstream server");
return(null);
}
string reusableMapKey = string.Concat(nameServer, port);
if (tcpClient == null && this.IsReuseTcpEnabled)
{
if (!this.reusableTcp.ContainsKey(reusableMapKey))
{
this.reusableTcp[reusableMapKey] = new ReusableTcpConnection();
}
ReusableTcpConnection reuse = this.reusableTcp[reusableMapKey];
tcpClient = reuse.Client;
tlsStream = reuse.Stream;
this.reusableTcp[reusableMapKey].LastUsed = DateTime.UtcNow;
}
try
{
if (tcpClient == null || (this.IsReuseTcpEnabled && !tcpClient.IsConnected()))
{
tcpClient = new TcpClient(nameServer.AddressFamily)
{
ReceiveTimeout = QueryTimeout,
SendTimeout = QueryTimeout
};
if (!await tcpClient.TryConnectAsync(nameServer, responderPort, QueryTimeout, token))
{
return(null);
}
SslStream sslStream = new SslStream(tcpClient.GetStream(), true, new RemoteCertificateValidationCallback(tlsServer.ValidateRemoteCertificate));
tlsStream = sslStream;
try
{
sslStream.AuthenticateAsClient(tlsServer.AuthName ?? string.Empty, new X509CertificateCollection(), tlsServer.SslProtocols, false);
}
catch (Exception)
{
}
if (!sslStream.IsAuthenticated)
{
Trace.TraceError("Error on dns query: invalid TLS upstream server certificate");
if (this.IsReuseTcpEnabled)
{
try
{
tlsStream.Dispose();
tcpClient.Close();
}
catch (Exception)
{
}
}
return(null);
}
}
int tmp = 0;
byte[] lengthBuffer = new byte[2];
if (messageLength > 0)
{
DnsMessageBase.EncodeUShort(lengthBuffer, ref tmp, (ushort)messageLength);
await tlsStream.WriteAsync(lengthBuffer, 0, 2, token);
await tlsStream.WriteAsync(messageData, 0, messageLength, token);
}
if (!await TryReadAsync(tcpClient, tlsStream, lengthBuffer, 2, token))
{
return(null);
}
tmp = 0;
int length = DnsMessageBase.ParseUShort(lengthBuffer, ref tmp);
byte[] resultData = new byte[length];
return(await TryReadAsync(tcpClient, tlsStream, resultData, length, token) ? new QueryResponse(resultData, nameServer, tcpClient, tlsStream, responderPort) : null);
}
catch (Exception e)
{
Trace.TraceError("Error on dns query: " + e);
return(null);
}
}
