#!/usr/bin/env python
# -
# SPDX-License-Identifier: BSD-2-Clause
#
# Copyright (c) 2020 Alexander V. Chernikov
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $FreeBSD$
#
from functools import partial
import socket
import scapy.all as sc
import argparse
import time
def parse_args():
parser = argparse.ArgumentParser(description='divert socket tester')
parser.add_argument('--dip', type=str, help='destination packet IP')
parser.add_argument('--sip', type=str, help='source packet IP')
parser.add_argument('--dmac', type=str, help='packet dst mac')
parser.add_argument('--smac', type=str, help='packet src mac')
parser.add_argument('--iface', type=str, help='interface to use')
parser.add_argument('--test_name', type=str, required=True,
help='test name to run')
return parser.parse_args()
def send_packet(args, pkt):
sc.sendp(pkt, iface=args.iface, verbose=False)
def is_icmp6_echo_request(pkt):
return pkt.type == 0x86DD and pkt.payload.nh == 58 and \
pkt.payload.payload.type == 128
def check_forwarded_ip_packet(orig_pkt, fwd_pkt):
"""
Checks that forwarded ICMP packet @fwd_ptk is the same as
@orig_pkt. Assumes router-on-the-stick forwarding behaviour:
* src/dst macs are swapped
* TTL is decremented
"""
# Check ether fields
assert orig_pkt.src == fwd_pkt.dst
assert orig_pkt.dst == fwd_pkt.src
assert len(orig_pkt) == len(fwd_pkt)
# Check IP
fwd_ip = fwd_pkt[sc.IP]
orig_ip = orig_pkt[sc.IP]
assert orig_ip.src == orig_ip.src
assert orig_ip.dst == fwd_ip.dst
assert orig_ip.ttl == fwd_ip.ttl + 1
# Check ICMP
fwd_icmp = fwd_ip[sc.ICMP]
orig_icmp = orig_ip[sc.ICMP]
assert bytes(orig_ip.payload) == bytes(fwd_ip.payload)
def fwd_ip_icmp_fast(args):
"""
Sends ICMP packet via args.iface interface.
Receives and checks the forwarded packet.
Assumes forwarding router decrements TTL
"""
def filter_f(x):
return x.src == args.dmac and x.type == 0x0800
e = sc.Ether(src=args.smac, dst=args.dmac)
ip = sc.IP(src=args.sip, dst=args.dip)
icmp = sc.ICMP(type='echo-request')
pkt = e / ip / icmp
send_cb = partial(send_packet, args, pkt)
packets = sc.sniff(iface=args.iface, started_callback=send_cb,
stop_filter=filter_f, lfilter=filter_f, timeout=5)
assert len(packets) > 0
fwd_pkt = packets[-1]
try:
check_forwarded_ip_packet(pkt, fwd_pkt)
except Exception as e:
print('Original packet:')
pkt.show()
print('Forwarded packet:')
fwd_pkt.show()
for a_packet in packets:
a_packet.summary()
raise Exception from e
def fwd_ip_icmp_slow(args):
"""
Sends ICMP packet via args.iface interface.
Forces slow path processing by introducing IP option.
Receives and checks the forwarded packet.
Assumes forwarding router decrements TTL
"""
def filter_f(x):
return x.src == args.dmac and x.type == 0x0800
e = sc.Ether(src=args.smac, dst=args.dmac)
# Add IP option to switch to 'normal' IP processing
stream_id = sc.IPOption_Stream_Id(security=0xFFFF)
ip = sc.IP(src=args.sip, dst=args.dip,
options=[sc.IPOption_Stream_Id(security=0xFFFF)])
icmp = sc.ICMP(type='echo-request')
pkt = e / ip / icmp
send_cb = partial(send_packet, args, pkt)
packets = sc.sniff(iface=args.iface, started_callback=send_cb,
stop_filter=filter_f, lfilter=filter_f, timeout=5)
assert len(packets) > 0
check_forwarded_ip_packet(pkt, packets[-1])
def check_forwarded_ip6_packet(orig_pkt, fwd_pkt):
"""
Checks that forwarded ICMP packet @fwd_ptk is the same as
@orig_pkt. Assumes router-on-the-stick forwarding behaviour:
* src/dst macs are swapped
* TTL is decremented
"""
# Check ether fields
assert orig_pkt.src == fwd_pkt.dst
assert orig_pkt.dst == fwd_pkt.src
assert len(orig_pkt) == len(fwd_pkt)
# Check IP
fwd_ip = fwd_pkt[sc.IPv6]
orig_ip = orig_pkt[sc.IPv6]
assert orig_ip.src == orig_ip.src
assert orig_ip.dst == fwd_ip.dst
assert orig_ip.hlim == fwd_ip.hlim + 1
# Check ICMPv6
assert bytes(orig_ip.payload) == bytes(fwd_ip.payload)
def fwd_ip6_icmp(args):
"""
Sends ICMPv6 packet via args.iface interface.
Receives and checks the forwarded packet.
Assumes forwarding router decrements TTL
"""
def filter_f(x):
return x.src == args.dmac and is_icmp6_echo_request(x)
e = sc.Ether(src=args.smac, dst=args.dmac)
ip = sc.IPv6(src=args.sip, dst=args.dip)
icmp = sc.ICMPv6EchoRequest()
pkt = e / ip / icmp
send_cb = partial(send_packet, args, pkt)
packets = sc.sniff(iface=args.iface, started_callback=send_cb,
stop_filter=filter_f, lfilter=filter_f, timeout=5)
assert len(packets) > 0
fwd_pkt = packets[-1]
try:
check_forwarded_ip6_packet(pkt, fwd_pkt)
except Exception as e:
print('Original packet:')
pkt.show()
print('Forwarded packet:')
fwd_pkt.show()
for idx, a_packet in enumerate(packets):
print('{}: {}'.format(idx, a_packet.summary()))
raise Exception from e
def main():
args = parse_args()
test_ptr = globals()[args.test_name]
test_ptr(args)
if __name__ == '__main__':
main()