ref: 106cbc54a185bca1efa644f3aed97a4b3e5e35eb
dir: /sys/src/cmd/python/Demo/sockets/broadcast.py/
# Send UDP broadcast packets
MYPORT = 50000
import sys, time
from socket import *
s = socket(AF_INET, SOCK_DGRAM)
s.bind(('', 0))
s.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)
while 1:
    data = repr(time.time()) + '\n'
    s.sendto(data, ('<broadcast>', MYPORT))
    time.sleep(2)