Go setup on Linux and write First Program in Go

Code for Magic packet:

import android.util.Log;

import java.io.IOException;

import java.net.InetAddress;

import java.net.UnknownHostException;

import java.net.DatagramSocket;

import java.net.DatagramPacket;

import java.net.SocketException;

import java.lang.IllegalArgumentException;

import java.lang.StringBuffer;

import java.util.regex.Pattern;

import java.util.regex.Matcher;

/**

* @desc Static WOL magic packet class

*/

public class MagicPacket

{

private static final String TAG = "MagicPacket";

public static final String BROADCAST = "192.168.1.255";

public static final int PORT = 9;

public static final char SEPARATOR = ':';

public static String send(String mac, String ip) throws UnknownHostException, SocketException, IOException, IllegalArgumentException

{

return send(mac, ip, PORT);

}

public static String send(String mac, String ip, int port) throws UnknownHostException, SocketException, IOException, IllegalArgumentException

{

// validate MAC and chop into array

final String[] hex = validateMac(mac);

// convert to base16 bytes

final byte[] macBytes = new byte[6];

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

macBytes[i] = (byte) Integer.parseInt(hex[i], 16);

}

final byte[] bytes = new byte[102];

// fill first 6 bytes

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

bytes[i] = (byte) 0xff;

}

// fill remaining bytes with target MAC

for(int i=6; i<bytes.length; i+=macBytes.length) {

System.arraycopy(macBytes, 0, bytes, i, macBytes.length);

}

// create socket to IP

final InetAddress address = InetAddress.getByName(ip);

final DatagramPacket packet = new DatagramPacket(bytes, bytes.length, address, port);

final DatagramSocket socket = new DatagramSocket();

socket.send(packet);

socket.close();

return hex[0]+SEPARATOR+hex[1]+SEPARATOR+hex[2]+SEPARATOR+hex[3]+SEPARATOR+hex[4]+SEPARATOR+hex[5];

}

public static String cleanMac(String mac) throws IllegalArgumentException

{

final String[] hex = validateMac(mac);

StringBuffer sb = new StringBuffer();

boolean isMixedCase = false;

// check for mixed case

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

sb.append(hex[i]);

}

String testMac = sb.toString();

if((testMac.toLowerCase().equals(testMac) == false) && (testMac.toUpperCase().equals(testMac) == false)) {

isMixedCase = true;

}

sb = new StringBuffer();

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

// convert mixed case to lower

if(isMixedCase == true) {

sb.append(hex[i].toLowerCase());

}else{

sb.append(hex[i]);

}

if(i < 5) {

sb.append(SEPARATOR);

}

}

return sb.toString();

}

private static String[] validateMac(String mac) throws IllegalArgumentException

{

// error handle semi colons

mac = mac.replace(";", ":");

// attempt to assist the user a little

String newMac = "";

if(mac.matches("([a-zA-Z0-9]){12}")) {

// expand 12 chars into a valid mac address

for(int i=0; i<mac.length(); i++){

if((i > 1) && (i % 2 == 0)) {

newMac += ":";

}

newMac += mac.charAt(i);

}

}else{

newMac = mac;

}

// regexp pattern match a valid MAC address

final Pattern pat = Pattern.compile("((([0-9a-fA-F]){2}[-:]){5}([0-9a-fA-F]){2})");

final Matcher m = pat.matcher(newMac);

if(m.find()) {

String result = m.group();

return result.split("(\\:|\\-)");

}else{

throw new IllegalArgumentException("Invalid MAC address");

}

}

public static void main(String[] args) {

if(args.length != 2) {

System.out.println("Usage: java MagicPacket <broadcast-ip> <mac-address>");

System.out.println("Example: java MagicPacket 192.168.0.255 00:0D:61:08:22:4A");

System.out.println("Example: java MagicPacket 192.168.0.255 00-0D-61-08-22-4A");

System.exit(1);

}

String ipStr = args[0];

String macStr = args[1];

try {

macStr = MagicPacket.cleanMac(macStr);

System.out.println("Sending to: "+macStr);

MagicPacket.send(macStr, ipStr);

}

catch(IllegalArgumentException e) {

System.out.println(e.getMessage());

}catch(Exception e) {

System.out.println("Failed to send Wake-on-LAN packet:" + e.getMessage());

}

}

}