/* Decode */
public static request_t Decode_request(request_t request)
{
/* ntohs */
byte[] bytes = BitConverter.GetBytes(request.port);
Array.Reverse(bytes);
request.port = BitConverter.ToUInt16(bytes, 0);
return(request);
}
/* Decode */
public request_t Decode_request(request_t request)
{
/* ntohs */
long converted_port = request.port;
converted_port = IPAddress.NetworkToHostOrder(converted_port);
request.port = (uint)converted_port;
return(request);
}
/* Encode */
public request_t Encode_request(request_t request)
{
/* htons */
long converted_port = request.port;
converted_port = IPAddress.HostToNetworkOrder(converted_port);
request.port = (uint)converted_port;
return(request);
}
public static Int32 GetPort()
{
const int NS_PORT = 50050;
const string NS_IP = "unix.cset.oit.edu";
const string SERVICE_NAME = "ftp_cal";
UdpClient ns_client = new UdpClient(NS_IP, NS_PORT);
request_t port_request = new request_t(0, LOOKUP_PORT, SUCCESS, SERVICE_NAME.ToCharArray());
int request_size = 54;
port_request = Encode_request(port_request);
byte[] converted_request = port_request.ToArray();
ns_client.Send(converted_request, request_size);
IPEndPoint RemoteIpEndPoint = new IPEndPoint(IPAddress.Any, 0);
/* Blocks until a message returns on this socket from a remote host. */
Byte[] receiveBytes = ns_client.Receive(ref RemoteIpEndPoint);
request_t ns_response = request_t.FromArray(receiveBytes);
ns_response = Decode_request(ns_response);
Console.WriteLine("Contacting nameserver...");
Console.WriteLine("looking up service name: " + SERVICE_NAME);
if (ns_response.port != 0)
{
Console.WriteLine("on port: " + ns_response.port + "\n");
}
ns_client.Close();
return(ns_response.port);
}
