ba22aeacf1
Pass/block packets in the forwarding path with pf. Introduce the pft_set_rules() helper function, because we need to remember to flush states between individual tests. If not we can get packets passing despite rules blocking them because they match states created in a previous test. Extend pft_ping.py to be able to send IPv6 echo requests.
146 lines
3.3 KiB
Python
146 lines
3.3 KiB
Python
#!/usr/local/bin/python2.7
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import argparse
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import scapy.all as sp
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import sys
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import threading
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PAYLOAD_MAGIC = 0x42c0ffee
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class Sniffer(threading.Thread):
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def __init__(self, recvif):
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threading.Thread.__init__(self)
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self._recvif = recvif
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self.start()
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def run(self):
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self.packets = sp.sniff(iface=self._recvif, timeout=3)
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def check_ping_request(packet, dst_ip, args):
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if args.ip6:
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return check_ping6_request(packet, dst_ip, args)
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else:
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return check_ping4_request(packet, dst_ip, args)
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def check_ping4_request(packet, dst_ip, args):
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"""
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Verify that the packet matches what we'd have sent
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"""
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ip = packet.getlayer(sp.IP)
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if not ip:
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return False
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if ip.dst != dst_ip:
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return False
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icmp = packet.getlayer(sp.ICMP)
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if not icmp:
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return False
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if sp.icmptypes[icmp.type] != 'echo-request':
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return False
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raw = packet.getlayer(sp.Raw)
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if not raw:
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return False
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if raw.load != str(PAYLOAD_MAGIC):
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return False
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# Wait to check expectations until we've established this is the packet we
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# sent.
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if args.expect_tos:
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if ip.tos != int(args.expect_tos[0]):
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print "Unexpected ToS value %d, expected %s" \
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% (ip.tos, args.expect_tos[0])
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return False
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return True
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def check_ping6_request(packet, dst_ip, args):
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"""
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Verify that the packet matches what we'd have sent
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"""
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ip = packet.getlayer(sp.IPv6)
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if not ip:
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return False
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if ip.dst != dst_ip:
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return False
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icmp = packet.getlayer(sp.ICMPv6EchoRequest)
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if not icmp:
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return False
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if icmp.data != str(PAYLOAD_MAGIC):
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return False
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return True
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def ping(send_if, dst_ip, args):
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ether = sp.Ether()
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ip = sp.IP(dst=dst_ip)
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icmp = sp.ICMP(type='echo-request')
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raw = sp.Raw(PAYLOAD_MAGIC)
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if args.send_tos:
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ip.tos = int(args.send_tos[0])
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req = ether / ip / icmp / raw
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sp.sendp(req, iface=send_if, verbose=False)
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def ping6(send_if, dst_ip, args):
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ether = sp.Ether()
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ip6 = sp.IPv6(dst=dst_ip)
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icmp = sp.ICMPv6EchoRequest(data=PAYLOAD_MAGIC)
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req = ether / ip6 / icmp
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sp.sendp(req, iface=send_if, verbose=False)
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def main():
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parser = argparse.ArgumentParser("pft_ping.py",
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description="Ping test tool")
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parser.add_argument('--sendif', nargs=1,
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required=True,
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help='The interface through which the packet(s) will be sent')
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parser.add_argument('--recvif', nargs=1,
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help='The interface on which to expect the ICMP echo response')
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parser.add_argument('--ip6', action='store_true',
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help='Use IPv6')
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parser.add_argument('--to', nargs=1,
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required=True,
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help='The destination IP address for the ICMP echo request')
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# Packet settings
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parser.add_argument('--send-tos', nargs=1,
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help='Set the ToS value for the transmitted packet')
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# Expectations
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parser.add_argument('--expect-tos', nargs=1,
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help='The expected ToS value in the received packet')
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args = parser.parse_args()
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# We may not have a default route. Tell scapy where to start looking for routes
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sp.conf.iface6 = args.sendif[0]
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sniffer = None
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if not args.recvif is None:
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sniffer = Sniffer(args.recvif[0])
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if args.ip6:
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ping6(args.sendif[0], args.to[0], args)
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else:
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ping(args.sendif[0], args.to[0], args)
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if sniffer:
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sniffer.join()
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for packet in sniffer.packets:
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if check_ping_request(packet, args.to[0], args):
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sys.exit(0)
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# We did not get the packet we expected
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sys.exit(1)
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if __name__ == '__main__':
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main()
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