private void EndTcpReadData(IAsyncResult ar)
{
TcpClient client = null;
NetworkStream stream = null;
try
{
object[] state = (object[])ar.AsyncState;
client = (TcpClient)state[0];
stream = (NetworkStream)state[1];
byte[] buffer = (byte[])state[2];
Timer timer = (Timer)state[3];
timer.Dispose();
stream.EndRead(ar);
DnsMessageBase query;
try
{
query = DnsMessageBase.Create(buffer, true, TsigKeySelector, null);
}
catch (Exception e)
{
throw new Exception("Error parsing dns query", e);
}
DnsMessageBase response = ProcessMessage(query, ((IPEndPoint)client.Client.RemoteEndPoint).Address, ProtocolType.Tcp);
if (response == null)
{
response = query;
query.IsQuery = false;
query.ReturnCode = ReturnCode.ServerFailure;
}
int length = response.Encode(out buffer, true);
timer = new Timer(TcpTimedOut, new object[] { client, stream }, 120000, System.Threading.Timeout.Infinite);
stream.BeginWrite(buffer, 0, length, EndTcpSendData, new object[] { client, stream, timer });
}
catch (Exception e)
{
try
{
if (stream != null)
{
stream.Close();
}
}
catch {}
try
{
if (client != null)
{
client.Close();
}
}
catch {}
OnExceptionThrown(e);
}
}
private void EndUdpReceive(IAsyncResult ar)
{
try
{
IPEndPoint endpoint = new IPEndPoint(IPAddress.Any, _DNS_PORT);
byte[] buffer = _udpClient.EndReceive(ar, ref endpoint);
DnsMessageBase query;
try
{
query = DnsMessageBase.Create(buffer, true, TsigKeySelector, null);
}
catch (Exception e)
{
throw new Exception("Error parsing dns query", e);
}
DnsMessageBase response = ProcessMessage(query, endpoint.Address, ProtocolType.Udp);
if (response == null)
{
response = query;
query.IsQuery = false;
query.ReturnCode = ReturnCode.ServerFailure;
}
int length = response.Encode(out buffer, false);
#region Truncating
DnsMessage message = response as DnsMessage;
if (message != null)
{
int maxLength = 512;
if (query.IsEDnsEnabled && message.IsEDnsEnabled)
{
maxLength = Math.Max(512, (int)message.EDnsOptions.UpdPayloadSize);
}
while (length > maxLength)
{
// First step: remove data from additional records except the opt record
if ((message.IsEDnsEnabled && (message.AdditionalRecords.Count > 1)) || (!message.IsEDnsEnabled && (message.AdditionalRecords.Count > 0)))
{
for (int i = message.AdditionalRecords.Count - 1; i >= 0; i--)
{
if (message.AdditionalRecords[i].RecordType != RecordType.Opt)
{
message.AdditionalRecords.RemoveAt(i);
}
}
length = message.Encode(out buffer, false);
continue;
}
int savedLength = 0;
if (message.AuthorityRecords.Count > 0)
{
for (int i = message.AuthorityRecords.Count - 1; i >= 0; i--)
{
savedLength += message.AuthorityRecords[i].MaximumLength;
message.AuthorityRecords.RemoveAt(i);
if ((length - savedLength) < maxLength)
{
break;
}
}
message.IsTruncated = true;
length = message.Encode(out buffer, false);
continue;
}
if (message.AnswerRecords.Count > 0)
{
for (int i = message.AnswerRecords.Count - 1; i >= 0; i--)
{
savedLength += message.AnswerRecords[i].MaximumLength;
message.AnswerRecords.RemoveAt(i);
if ((length - savedLength) < maxLength)
{
break;
}
}
message.IsTruncated = true;
length = message.Encode(out buffer, false);
continue;
}
if (message.Questions.Count > 0)
{
for (int i = message.Questions.Count - 1; i >= 0; i--)
{
savedLength += message.Questions[i].MaximumLength;
message.Questions.RemoveAt(i);
if ((length - savedLength) < maxLength)
{
break;
}
}
message.IsTruncated = true;
length = message.Encode(out buffer, false);
continue;
}
}
}
#endregion
_udpClient.BeginSend(buffer, length, endpoint, EndUdpSend, null);
}
catch (Exception e)
{
OnExceptionThrown(e);
}
StartUdpListen();
}