<?php
 
/**
 * exception class for failed socket connection
 *
 */
class SocketConnectionException extends Exception { }
 
/**
 * exception class for failed wake on lan request
 *
 */
class WakeOnLANException extends Exception { }
 
/**
 * a function to wake any computer using "Wake on LAN"
 *
 * @link https://en.wikipedia.org/wiki/Wake-on-LAN
 * @author Toni Uebernickel <tuebernickel@whitestarprogramming.de>
 * @copyright https://sam.zoy.org/wtfpl/
 *
 * @version 1.0
 * @todo 1.1 Check for valid (reachable) host.
 * @todo 1.1 Validate the given MAC Address.
 *
 * @example WakeOnLAN('13:37:13:37:13:37', 'host.domain');
 * @example WakeOnLAN('13:37:13:37:13:37', '10.65.0.151', 7);
 *
 * @see https://www.php.net/fsockopen
 * @throws SocketConnectionException if connection could not be established ErrorCode: defined by fsockopen
 * @throws WakeOnLANException if amount of sent bytes is not 102 (needed for WOL) ErrorCode: E_ERROR
 *
 * @param string $macAddress The MAC address to send the WOL package for.
 * @param string $hostAddress The address to which the WOL request will be sent (may be an IP or any hostname).
 * @param int $hostPort The destination port on which the WOL request will be sent.
 *
 * @return bool Returns true if Wake On LAN magic packet was sent successfully.
 */
function WakeOnLAN($macAddress, $hostAddress, $hostPort = 9)
{
  // check for given parameters and exit if either is not given
  if (!$macAddress or !$hostAddress or !intval($hostPort))
  {
    return false;
  }
 
  // add UDP protocol handler prefix
  $hostAddress = 'udp://' . $hostAddress;
 
  /**
   * The data string that will be sent to the destination host.
   */
  $WakeOnLANSequence = null;
 
  /**
   * Error variables set if socket connection fails.
   * Both are passed by reference to fsockopen().
   */
  $errNo = $errMessage = null;
 
  /**
   * Open the socket through which the Wake On LAN data sequence will be sent.
   *
   * Surpressing E_NOTICE || E_WARNING of fsockopen() due to error handling with exceptions.
   */
  if ($socket = @fsockopen($hostAddress, $hostPort, $errNo, $errMessage))
  {
    /**
     * Initialize the first six bytes for the Wake On LAN magic packet.
     *
     * @see https://en.wikipedia.org/wiki/Wake-on-LAN#Magic_Packet
     */
    $WakeOnLANSequence = "\xFF\xFF\xFF\xFF\xFF\xFF";
 
    /**
     * Strip MAC address to an hexidecimal string.
     *
     * @see https://en.wikipedia.org/wiki/MAC_address
     *
     * This call removes all characters but 0 to 9 and A to F (a to f).
     */
    $macAddress = preg_replace('/[^0-9A-Fa-f]/', '', $macAddress);
 
    /**
     * Encode the MAC address into ASCII characters.
     *
     * substr(): get each separated set of the MAC address
     * hexdec(): convert the set to decimal values used by ASCII
     * chr(): convert the decimal value into the ASCII character
     *
     * @see https://en.wikipedia.org/wiki/ASCII
     */
    for ($i = 0; $i < 12; $i += 2)
    {
      $macAddressHex .= chr(hexdec(substr($macAddress, $i, 2)));
    }
 
    /**
     * Complete the magic packet by adding the MAC address 16 times after the initialized six byte sequence.
     *
     * @see https://en.wikipedia.org/wiki/Wake-on-LAN#Magic_Packet
     */
    for ($i = 0; $i < 16; $i++)
    {
      $WakeOnLANSequence .= $macAddressHex;
    }
 
    /**
     * Send the magic packet through the open socket and save the amount of sent bytes.
     *
     * Surpressing E_NOTICE || E_WARNING again due to error handling.
     */
    $bytesSent = @fputs($socket, $WakeOnLANSequence);
 
    /**
     * Finally close the socket and once again surpress any E_NOTICE || E_WARNING.
     */
    if (@fclose($socket) and $bytesSent === 102)
    {
      /**
       * This returns the successful delivery of the Wake On LAN magic packet described below.
       * However, this does not ensure the requested host is now up and running.
       *
       * If the host did not wake up:
       * Check your NAT and any other network configuration between this script server and the destination host.
       * Check the hosts' configuration about Wake On LAN.
       *
       * @see https://en.wikipedia.org/wiki/Wake-on-LAN#Magic_Packet
       */
      return true;
    }
    else
    {
      // The byte sequence is corrupt or was not sent properly.
      throw new WakeOnLANException('Wake On LAN failed, sent ' . $bytesSent . ' out of 102 bytes', E_ERROR);
    }
  }
  else
  {
    // The socket could not be opened.
    throw new SocketConnectionException('Could not open socket to ' . $hostAddress . ' on port ' . $hostPort . '. Error: ' . $errMessage, $errNo);
  }
}

<?php
include_once('wake_on_lan.php');

try
{
  WakeOnLAN('13:37:13:37:13:37', '192.168.0.10');
}
catch (SocketConnectionException $e)
{
  // socket connection failed
  echo 'The socket connection could not be established.', "\n", $e;
}
catch (WakeOnLANException $e)
{
  // wake on lan request failed
  echo 'The Wake On LAN packet was not sent properly.', "\n", $e;
}