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#!/usr/bin/python
# need root privileges
import struct
import sys
import time
import asyncore
from socket import AF_INET, AF_INET6, inet_ntoa
sys.path.append('python')
sys.path.append('build/python')
import nfqueue
sys.path.append('dpkt-1.6')
from dpkt import ip
def cb(i,payload):
print "python callback called !", i
print "payload len ", payload.get_length()
data = payload.get_data()
pkt = ip.IP(data)
print "proto:", pkt.p
print "source: %s" % inet_ntoa(pkt.src)
print "dest: %s" % inet_ntoa(pkt.dst)
if pkt.p == ip.IP_PROTO_TCP:
print " sport: %s" % pkt.tcp.sport
print " dport: %s" % pkt.tcp.dport
payload.set_verdict(nfqueue.NF_DROP)
sys.stdout.flush()
return 1
class AsyncNfQueue(asyncore.file_dispatcher):
"""An asyncore dispatcher of nfqueue events.
"""
def __init__(self, cb, nqueue=0, family=AF_INET, maxlen=5000, map=None):
self._q = nfqueue.queue()
self._q.set_callback(cb)
self._q.fast_open(nqueue, family)
self._q.set_queue_maxlen(maxlen)
self.fd = self._q.get_fd()
asyncore.file_dispatcher.__init__(self, self.fd, map)
self._q.set_mode(nfqueue.NFQNL_COPY_PACKET)
def handle_read(self):
print "Processing at most 5 events"
self._q.process_pending(5)
# We don't need to check for the socket to be ready for writing
def writable(self):
return False
async_queue = AsyncNfQueue(cb)
asyncore.loop()
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