WakeOnLan ported to C#

Paul Mutton wrote a great article on how to use Wake-On-Lan which includes a tutorial on how to create a Magic Packet sender in Java.  He even provides the source of his java implementation: http://www.jibble.org/wake-on-lan/

I took the liberty of converting it to C# with a few minor modifications.  It allows a user to specify a Port number manually.

WHY C#?  Well why not?  I'm using C# at work so it comes naturally.  Mono gives me the ability to run code on both Windows and Linux.  Yes, so does Java.  There are a variety of tools out there and I like to familiarize myself with a good number of them.  In this spirit, I am currently writing a small connection testing tool in Java using Swing.  Maybe I'll write another port of Wake-On-LAN in C++ for fun.

Here is the C# code below:

using System;

using System.Net;

using System.Net.Sockets;

namespace WakeOnLan

{

    class Program

    {       

        static void Main(string[] args)

        {

            string macAdd = "";

            string ip = "";

            string port = "9";

            int iPort = 0;

            if (args.Length < 2) {

                System.Console.WriteLine("Usage: wakeonlan <broadcast-ip> <mac-address> [<port>]");

                System.Console.WriteLine("Example: wakeonlan 192.168.0.255 00:0D:61:08:22:4A");

                System.Console.WriteLine("Example: wakeonlan 192.168.0.255 00-0D-61-08-22-4A");

                System.Environment.Exit(1);

            }

            ip = args[0];

            macAdd = args[1];

            if (args.Length > 2)           

                port = args[2];

            if (!IsNumeric(port))

            {

                System.Console.WriteLine("Port entered was not a number...");

                return; // quit

            }                     

            iPort = Int32.Parse(port);

            if (iPort > 65535 || iPort < 0)

            {

                System.Console.WriteLine("Port value is invalid");

                return;

            }

            byte[] mac = getMacBytes(macAdd);

            //byte[] mac = new byte[] { 0x00, 0x0F, 0x1F, 0x20, 0x2D, 0x35 };

            WakeUp(mac, iPort, ip);

        }

        ///

        /// Check whether string can be converted to a number value

        ///

        private static bool IsNumeric(string num)

        {

            try

            {

                double d = Double.Parse(num);

                return true;

            }

            catch

            {

                return false;

            }

        }

        ///

        /// Sends a Wake-On-Lan packet to the specified MAC address.

        ///

        private static void WakeUp(byte[] mac, Int32 iPort, string myIP)

        {

            //

            // WOL packet is sent over UDP 255.255.255.0:40000.

            //

            UdpClient client = new UdpClient();

            client.Connect(myIP, iPort);

            //

            // WOL packet contains a 6-bytes trailer and 16 times a 6-bytes sequence 

            // containing the MAC address.

            byte[] packet = new byte[17 * 6];

            //

            // Trailer of 6 times 0xFF.

            //

            for (int i = 0; i < 6; i++)

                packet[i] = 0xFF;

            //

            // Body of magic packet contains 16 times the MAC address.

            //

            for (int i = 1; i <= 16; i++)

                for (int j = 0; j < 6; j++)

                    packet[i * 6 + j] = mac[j];

            //

            // Submit WOL packet.

            //

            client.Send(packet, packet.Length);

            System.Console.WriteLine("Wake-on-LAN packet sent.");

        }

   

        private static byte[] getMacBytes(String macStr)

        {

            byte[] bytes = new byte[6];

            string[] hex = macStr.Split(new Char[] { ':', '-' });

            if (hex.Length != 6) {

                throw new ArgumentException("Invalid MAC address.");

            }

            try {

                for (int i = 0; i < 6; i++) {

                    Int32 intVal = Int32.Parse(hex[i], System.Globalization.NumberStyles.AllowHexSpecifier);

                    bytes[i] = (byte)intVal;

                }

            }

            catch (FormatException e) {

                throw new ArgumentException("Invalid hex digit in MAC address.");

            }

            return bytes;

        }

    }

}