multicast echo example

multicast_echo.py

import sys
import socket
import struct

def multicast_receive(multicast_group, port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

    sock.bind(('', port))

    group = socket.inet_aton(multicast_group)
    mreq = struct.pack('4sL', group, socket.INADDR_ANY)
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)

    return sock

def main():
    addr, port = sys.argv[1].split(':')
    sock = multicast_receive(addr, int(port))

    while True:
        print("waiting to receive message")
        data, address = sock.recvfrom(1024)

        print('received %s bytes from %s' % (len(data), address))


if __name__ == '__main__':
    if len(sys.argv) < 2:
        print("Usage: %s address:port" % sys.argv[0])
        sys.exit(-1)
    main()