public IPAddress QueryName(string name)
{
DnsRequest request = new DnsRequest(new Question(EncodeName(name), DnsType.NB, DnsClass.IN));
request.Header.RD = true;
request.Header.B = true;
DnsResponse res = Invoke(request);
if (res == null ||
#if (MF)
res.Answers.Length == 0
#else
res.Answers.Count == 0
#endif
)
{
return(null);
}
NBRecord nb = res.Answers[0].Record as NBRecord;
if (nb == null)
{
return(null);
}
return(nb.IPAddress);
}
public bool Register(string name, IPAddress address)
{
DnsRequest request = new DnsRequest(new Question(EncodeName(name), DnsType.NB, DnsClass.IN));
request.Header.Opcode = OpcodeType.Registration;
request.Header.RA = false;
request.Header.RD = false;
request.Header.B = false;
Additional add = new Additional();
add.Domain = EncodeName(name);
add.Class = DnsClass.IN;
add.Type = DnsType.NB;
add.Ttl = 30000;
NBRecord nb = new NBRecord(address);
add.Record = nb;
#if (MF)
request.AdditionalRecords = new Additional[] { add };
#else
request.AdditionalRecords.Add(add);
#endif
DnsResponse res = Invoke(request, false);
return(true);
}
public DnsResponse Resolve(DnsRequest request)
{
int attempts = 0;
if (request.Header.MessageID == 0)
{
request.Header.MessageID = _nextMessageID++;
}
while (attempts <= _maxRetryAttemps)
{
byte[] bytes = request.GetMessage();
if (bytes.Length > 512)
{
throw new ArgumentException("RFC 1035 2.3.4 states that the maximum size of a UDP datagram is 512 octets (bytes).");
}
Socket socket = new Socket(
#if (MF)
AddressFamily.InterNetwork
#else
_endPoint.AddressFamily
#endif
, SocketType.Dgram, ProtocolType.Udp);
socket.ReceiveTimeout = 300;
//socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 300);
socket.SendTo(bytes, bytes.Length, SocketFlags.None, _endPoint);
// Messages carried by UDP are restricted to 512 bytes (not counting the IP
// or UDP headers). Longer messages are truncated and the TC bit is set in
// the header. (RFC 1035 4.2.1)
byte[] responseMessage = new byte[512];
try
{
//int numBytes = socket.Receive(responseMessage);
EndPoint ep = (EndPoint)_endPoint;
int numBytes = socket.ReceiveFrom(responseMessage, ref ep);
if (numBytes == 0 || numBytes > 512)
{
throw new Exception("RFC 1035 2.3.4 states that the maximum size of a UDP datagram is 512 octets (bytes).");
}
DnsReader br = new DnsReader(responseMessage);
DnsResponse res = new DnsResponse(br);
if (request.Header.MessageID == res.Header.MessageID)
{
return(res);
}
_lastException = new Exception("Not the answer for the current query.");
attempts++;
}
catch (SocketException se)
{
_lastException = se;
attempts++;
}
finally
{
socket.Close();
socket = null;
}
}
throw new Exception("Could not resolve the query (" + attempts + " attempts).");
}
internal DnsResponse Invoke(DnsRequest request, bool isQuery)
{
int attempts = 0;
if (request.Header.MessageID == 0)
{
request.Header.MessageID = _nextMessageID++;
}
while (attempts <= _maxRetryAttemps)
{
byte[] bytes = request.GetMessage();
if (bytes.Length > 512)
{
throw new ArgumentException("RFC 1035 2.3.4 states that the maximum size of a UDP datagram is 512 octets (bytes).");
}
Socket socket = null;
try
{
socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
socket.ReceiveTimeout = 300;
//socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 300);
#if (DEBUG && MF)
Microsoft.SPOT.Debug.Print(MFToolkit.IO.ByteUtil.PrintBytes(bytes));
#endif
socket.SendTo(bytes, bytes.Length, SocketFlags.None, new IPEndPoint(IPAddress.Parse("192.168.178.255"), 137));
if (!isQuery)
{
return(null);
}
// Messages carried by UDP are restricted to 512 bytes (not counting the IP
// or UDP headers). Longer messages are truncated and the TC bit is set in
// the header. (RFC 1035 4.2.1)
byte[] responseMessage = new byte[512];
//int numBytes = socket.Receive(responseMessage);
EndPoint ep = (EndPoint) new IPEndPoint(new IPAddress(4294967295), 137);
int numBytes = socket.ReceiveFrom(responseMessage, ref ep);
if (numBytes == 0 || numBytes > 512)
{
throw new Exception("RFC 1035 2.3.4 states that the maximum size of a UDP datagram is 512 octets (bytes).");
}
DnsReader br = new DnsReader(responseMessage);
DnsResponse res = new DnsResponse(br);
if (request.Header.MessageID == res.Header.MessageID)
{
return(res);
}
_lastException = new Exception("Not the answer for the current query.");
attempts++;
}
catch (SocketException se)
{
_lastException = se;
attempts++;
}
finally
{
socket.Close();
socket = null;
}
}
throw new Exception("Could not resolve the query (" + attempts + " attempts).");
}