WakeOnLan.java

/*
 * WakeOnLan.java
 * Copyright (C) 2011,2012 Wannes De Smet
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.xenmaster.connectivity;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

import org.apache.log4j.Logger;

/**
 * 
 * @created Oct 8, 2011
 * @author double-u
 */
public class WakeOnLan {

    // WOL functionality from http://www.jibble.org/wake-on-lan/
    public static boolean wakeHost(String ipAddress, String macAddress, boolean confirmHostIsUp) {
        try {
            byte[] macBytes = getMacBytes(macAddress);
            byte[] bytes = new byte[6 + 16 * macBytes.length];
            for (int i = 0; i < 6; i++) {
                bytes[i] = (byte) 0xff;
            }
            for (int i = 6; i < bytes.length; i += macBytes.length) {
                System.arraycopy(macBytes, 0, bytes, i, macBytes.length);
            }

            InetAddress address = InetAddress.getByName(ipAddress);
            DatagramPacket packet = new DatagramPacket(bytes, bytes.length, address, 9);
            DatagramSocket socket = new DatagramSocket();
            socket.send(packet);
            socket.close();

            Logger.getLogger(WakeOnLan.class).info("Wake on LAN packet sent to " + ipAddress);

            if (!confirmHostIsUp) {
                return true;
            }
            return address.isReachable(10000);
        } catch (IllegalArgumentException | IOException e) {
            Logger.getLogger(WakeOnLan.class).error(e);
        }

        return false;
    }

    private static byte[] getMacBytes(String macStr) throws IllegalArgumentException {
        byte[] bytes = new byte[6];
        String[] hex = macStr.split("(\\:|\\-)");
        if (hex.length != 6) {
            throw new IllegalArgumentException("Invalid MAC address.");
        }
        try {
            for (int i = 0; i < 6; i++) {
                bytes[i] = (byte) Integer.parseInt(hex[i], 16);
            }
        } catch (NumberFormatException e) {
            throw new IllegalArgumentException("Invalid hex digit in MAC address.");
        }
        return bytes;
    }
}