Python Multicast Listen DHCP.py

# Python code sample to listen to TCP multicast traffic on 
# port 67 (?), which should be traffic destined to a DHCP server
# that will listen to multicast on that port.
# Tested on OSX.

import socket

s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
# Next line might or might not work, depending on your platform.
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1) 

s.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_TTL, 20)
s.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_LOOP, 1)

dhcp_server_port=67 # DHCP Traffic trying to reach a server (not sure actually...)
addr="0.0.0.0" # From all Interfaces/IPs
buf_size=1024

s.bind(('', dhcp_server_port))

intf = socket.gethostbyname(socket.gethostname())
s.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_IF, socket.inet_aton(intf))

# "IP_ADD_MEMBERSHIP" is an invalid argument on (OSX at least).
#s.setsockopt(socket.SOL_IP, socket.IP_ADD_MEMBERSHIP, socket.inet_aton(addr) + socket.inet_aton(intf))

data, sender_addr = s.recvfrom(buf_size)

# "IP_DROP_MEMBERSHIP" is also an invalid argument on (OSX at least).
#s.setsockopt(socket.SOL_IP, socket.IP_DROP_MEMBERSHIP, socket.inet_aton(addr) + socket.inet_aton('0.0.0.0'))

s.close()

print ":".join("{:02x}".format(ord(c)) for c in data)