.net getlobbyid (spring lobby protcol)

getlobbyid.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.NetworkInformation;

namespace LobbyClient {
    using System;
    public class Crc32 {
        static uint[] table;

        static public uint ComputeChecksum(byte[] bytes) {
            uint crc = 0xffffffff;
            for(int i = 0; i < bytes.Length; ++i) {
                byte index = (byte)(((crc) & 0xff) ^ bytes[i]);
                crc = (uint)((crc >> 8) ^ table[index]);
            }
            return ~crc;
        }

        static Crc32() {
            uint poly = 0xedb88320;
            table = new uint[256];
            uint temp = 0;
            for(uint i = 0; i < table.Length; ++i) {
                temp = i;
                for(int j = 8; j > 0; --j) {
                    if((temp & 1) == 1) {
                        temp = (uint)((temp >> 1) ^ poly);
                    }else {
                        temp >>= 1;
                    }
                }
                table[i] = temp;
            }
        }
    }
}

public class Crc
{
	public static string GetMyUserID() {
		var nics = NetworkInterface.GetAllNetworkInterfaces().Where(x=> !String.IsNullOrWhiteSpace(x.GetPhysicalAddress().ToString())
			&& x.NetworkInterfaceType != NetworkInterfaceType.Loopback && x.NetworkInterfaceType != NetworkInterfaceType.Tunnel);
	
		var wantedNic = nics.FirstOrDefault();
	
		if (wantedNic != null)
		{
			return LobbyClient.Crc32.ComputeChecksum(wantedNic.GetPhysicalAddress().GetAddressBytes()).ToString();
		}
		return "0";
	}

	public static void Main()
	{
		System.Console.WriteLine(GetMyUserID());
	}

}