WakeOnLan.py

# WakeOnLan
#
# Sends a wake-on-lan magic packet for the given MAC address 
# to either the broadcast address of the local subnet, or,
# if provided, some other hostname.
# An alternate port can also be optionally provided.

import struct, socket
import sys


def wake(mac_address, hostname=None, port=9):

  # Convert the MAC address to a packed binary form
  addr_bytes = ''.join(chr(int(byte, 16)) for byte in mac_address.split(':'))

  # Construct the WOL "magic packet"...
  payload = b'\xFF' * 6 + addr_bytes * 16

  if not hostname:
    # If no hostname is specified, broadcast as a UDP packet on the local subnet
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    try:
      s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
      s.sendto(payload, ('<broadcast>', port))
      print 'Magic packet for ' + mac_address + \
            ' has been sent to broadcast address with port ' + str(port)
    finally:
      s.close()

  else:
    # If a hostname is specified, resolve it, etc, and send the UDP packet
    try:
      records = socket.getaddrinfo(hostname, port, socket.AF_UNSPEC, socket.SOCK_DGRAM)
    except socket.gaierror as e:
      print '\nCould not resolve host "' + hostname + '": ' + e[1]
      sys.exit(1)
    for res in records:
      af, socktype, proto, canonname, sa = res
      try:
        s = socket.socket(af, socktype, proto)
      except socket.error as msg:
        s = None
        continue
      try:
        s.connect(sa)
      except socket.error as msg:
        s.close()
        s = None
        continue
      break
    if s is None:
      print '\nCould not open socket'
      sys.exit(1)
    s.send(payload)
    print 'Magic packet for ' + mac_address + \
          ' has been sent to ' + sa[0] + \
          ' port ' + str(port)
    s.close()


if __name__ == '__main__':
  # Example uses
  wake('aa:bb:cc:dd:ee:ff', 'myhost.example.org')
  wake('aa:bb:cc:dd:ee:ff')