python udp multicast

mcast.py

#!/usr/bin/env python

import socket
import binascii

payload = "4141414141"
payload = binascii.unhexlify(payload)
MCAST_GRP = '224.0.0.22'
MCAST_PORT = 4444
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
try:
  sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
except AttributeError:
  pass
sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 32)
sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, 1)

sock.bind(('', MCAST_PORT))
#host = socket.gethostbyname(socket.gethostname())
host = '10.42.0.1'
sock.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_IF, socket.inet_aton(host))
sock.setsockopt(socket.SOL_IP, socket.IP_ADD_MEMBERSHIP, socket.inet_aton(MCAST_GRP) + socket.inet_aton(host))

while 1:
  try:
    data, addr = sock.recvfrom(1024)
  except socket.error, e:
    print 'Expection'
  hexdata = binascii.hexlify(data)
  print 'Addr = %s' % repr(addr)
  print 'Data = %s' % hexdata
  sock.sendto(payload, addr)