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)."); }