private void TcpBeginConnect <TMessage>(DnsClientAsyncState <TMessage> state)
where TMessage : DnsMessageBase, new()
{
if (state.EndpointInfoIndex == state.EndpointInfos.Count)
{
state.TcpStream = null;
state.TcpClient = null;
state.SetCompleted();
return;
}
TcpBeginConnect(state, state.EndpointInfos[state.EndpointInfoIndex].ServerAddress);
}
private void UdpBeginSend <TMessage>(DnsClientAsyncState <TMessage> state)
where TMessage : DnsMessageBase, new()
{
if (state.EndpointInfoIndex == state.EndpointInfos.Count)
{
state.UdpClient = null;
state.UdpEndpoint = null;
state.SetCompleted();
return;
}
try
{
DnsClientEndpointInfo endpointInfo = state.EndpointInfos[state.EndpointInfoIndex];
state.UdpEndpoint = new IPEndPoint(endpointInfo.ServerAddress, _port);
state.UdpClient = new System.Net.Sockets.Socket(state.UdpEndpoint.AddressFamily, SocketType.Dgram, ProtocolType.Udp);
PrepareAndBindUdpSocket(endpointInfo, state.UdpClient);
state.TimedOut = false;
state.TimeRemaining = QueryTimeout;
IAsyncResult asyncResult = state.UdpClient.BeginSendTo(state.QueryData, 0, state.QueryLength, SocketFlags.None, state.UdpEndpoint, UdpSendCompleted <TMessage>, state);
state.Timer = new Timer(UdpTimedOut <TMessage>, asyncResult, state.TimeRemaining, Timeout.Infinite);
}
catch (Exception e)
{
Trace.TraceError("Error on dns query: " + e);
try
{
state.UdpClient.Close();
state.Timer.Dispose();
}
catch {}
state.EndpointInfoIndex++;
UdpBeginSend(state);
}
}
private void UdpReceiveCompleted <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++;
UdpBeginSend(state);
}
else
{
try
{
int length = state.UdpClient.EndReceiveFrom(ar, ref state.UdpEndpoint);
byte[] responseData = new byte[length];
Buffer.BlockCopy(state.Buffer, 0, responseData, 0, length);
TMessage response = DnsMessageBase.Parse <TMessage>(responseData, state.TSigKeySelector, state.TSigOriginalMac);
if (AreMultipleResponsesAllowedInParallelMode)
{
if (ValidateResponse(state.Query, response))
{
if (response.IsTcpResendingRequested)
{
TcpBeginConnect <TMessage>(state.CreateTcpCloneWithoutCallback(), ((IPEndPoint)state.UdpEndpoint).Address);
}
else
{
state.Responses.Add(response);
}
}
state.Buffer = new byte[65535];
if (state.EndpointInfos[state.EndpointInfoIndex].IsMulticast)
{
state.UdpEndpoint = new IPEndPoint(state.UdpClient.AddressFamily == AddressFamily.InterNetwork ? IPAddress.Any : IPAddress.IPv6Any, _port);
}
IAsyncResult asyncResult = state.UdpClient.BeginReceiveFrom(state.Buffer, 0, state.Buffer.Length, SocketFlags.None, ref state.UdpEndpoint, UdpReceiveCompleted <TMessage>, state);
state.Timer = new Timer(UdpTimedOut <TMessage>, asyncResult, state.TimeRemaining, Timeout.Infinite);
}
else
{
state.UdpClient.Close();
state.UdpClient = null;
state.UdpEndpoint = null;
if (!ValidateResponse(state.Query, response) || (response.ReturnCode == ReturnCode.ServerFailure))
{
state.EndpointInfoIndex++;
UdpBeginSend(state);
}
else
{
if (response.IsTcpResendingRequested)
{
TcpBeginConnect <TMessage>(state, ((IPEndPoint)state.UdpEndpoint).Address);
}
else
{
state.Responses.Add(response);
state.SetCompleted();
}
}
}
}
catch (Exception e)
{
Trace.TraceError("Error on dns query: " + e);
try
{
state.UdpClient.Close();
state.Timer.Dispose();
}
catch {}
state.EndpointInfoIndex++;
UdpBeginSend(state);
}
}
}
private void TcpReceiveCompleted <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, state.Buffer.Length - state.TcpBytesToReceive, state.TcpBytesToReceive, TcpReceiveCompleted <TMessage>, state);
state.Timer = new Timer(TcpTimedOut <TMessage>, asyncResult, state.TimeRemaining, Timeout.Infinite);
}
else
{
byte[] buffer = state.Buffer;
state.Buffer = null;
TMessage response = DnsMessageBase.Parse <TMessage>(buffer, state.TSigKeySelector, state.TSigOriginalMac);
if (!ValidateResponse(state.Query, response) || (response.ReturnCode == ReturnCode.ServerFailure))
{
state.EndpointInfoIndex++;
state.PartialMessage = null;
state.TcpStream.Close();
state.TcpClient.Close();
state.TcpStream = null;
state.TcpClient = null;
TcpBeginConnect(state);
}
else
{
bool isSubsequentResponseMessage = (state.PartialMessage != null);
if (isSubsequentResponseMessage)
{
state.PartialMessage.AnswerRecords.AddRange(response.AnswerRecords);
}
else
{
state.PartialMessage = response;
}
if (response.IsTcpNextMessageWaiting(isSubsequentResponseMessage))
{
state.TcpBytesToReceive = 2;
state.Buffer = new byte[2];
IAsyncResult asyncResult = state.TcpStream.BeginRead(state.Buffer, 0, 2, TcpReceiveLengthCompleted <TMessage>, state);
state.Timer = new Timer(TcpTimedOut <TMessage>, asyncResult, state.TimeRemaining, Timeout.Infinite);
}
else
{
state.TcpStream.Close();
state.TcpClient.Close();
state.TcpStream = null;
state.TcpClient = null;
state.Responses.Add(state.PartialMessage);
state.SetCompleted();
}
}
}
}
catch (Exception e)
{
Trace.TraceError("Error on dns query: " + e);
try
{
state.TcpClient.Close();
state.Timer.Dispose();
}
catch {}
state.EndpointInfoIndex++;
TcpBeginConnect(state);
}
}
}
