1#!/usr/bin/env python 2#- 3# SPDX-License-Identifier: BSD-2-Clause 4# 5# Copyright (c) 2019 Netflix, Inc. 6# 7# Redistribution and use in source and binary forms, with or without 8# modification, are permitted provided that the following conditions 9# are met: 10# 1. Redistributions of source code must retain the above copyright 11# notice, this list of conditions and the following disclaimer. 12# 2. Redistributions in binary form must reproduce the above copyright 13# notice, this list of conditions and the following disclaimer in the 14# documentation and/or other materials provided with the distribution. 15# 16# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26# SUCH DAMAGE. 27# 28# $FreeBSD$ 29# 30 31import argparse 32import logging 33logging.getLogger("scapy").setLevel(logging.CRITICAL) 34import scapy.all as sp 35import socket 36import sys 37from sniffer import Sniffer 38from time import sleep 39 40def check_icmp6_error(args, packet): 41 ip6 = packet.getlayer(sp.IPv6) 42 if not ip6: 43 return False 44 oip6 = sp.IPv6(src=args.src[0], dst=args.to[0]) 45 if ip6.dst != oip6.src: 46 return False 47 icmp6 = packet.getlayer(sp.ICMPv6TimeExceeded) 48 if not icmp6: 49 return False 50 # ICMP6_TIME_EXCEED_REASSEMBLY 1 51 if icmp6.code != 1: 52 return False 53 # Should we check the payload as well? 54 # We are running in a very isolated environment and nothing else 55 # should trigger an ICMPv6 Time Exceeded / Frag reassembly so leave it. 56 #icmp6.display() 57 return True 58 59 60def main(): 61 parser = argparse.ArgumentParser("frag6.py", 62 description="IPv6 fragementation test tool") 63 parser.add_argument('--sendif', nargs=1, 64 required=True, 65 help='The interface through which the packet will be sent') 66 parser.add_argument('--recvif', nargs=1, 67 required=True, 68 help='The interface on which to check for the packet') 69 parser.add_argument('--src', nargs=1, 70 required=True, 71 help='The source IP address') 72 parser.add_argument('--to', nargs=1, 73 required=True, 74 help='The destination IP address') 75 parser.add_argument('--debug', 76 required=False, action='store_true', 77 help='Enable test debugging') 78 79 args = parser.parse_args() 80 81 82 # Start sniffing on recvif 83 sniffer = Sniffer(args, check_icmp6_error) 84 85 86 ######################################################################## 87 # 88 # Send a proper first fragment (off=0) and a second fragment which 89 # just fits the 64k. The re-send the first fragment with an extra 90 # unfragmentable part making the 64k to exceed the limit. 91 # This is to make sure we don't allow to update meta-data for a 92 # 1st fragmented packet should a second arrive but given the 93 # fragmentable part is an exact duplicate only that fragment 94 # will be silently discarded. 95 # 96 # A: Reassembly failure, timeout after 97 # R: ICMPv6 time exceeded / statistics for the duplicate 98 # 99 data = "6" * 8 100 ip6f00 = \ 101 sp.Ether() / \ 102 sp.IPv6(src=args.src[0], dst=args.to[0]) / \ 103 sp.IPv6ExtHdrFragment(offset=0, m=1, id=20) / \ 104 sp.UDP(dport=3456, sport=6543) / \ 105 data 106 data = "6" * 15 107 ip6f01 = \ 108 sp.Ether() / \ 109 sp.IPv6(src=args.src[0], dst=args.to[0]) / \ 110 sp.IPv6ExtHdrFragment(offset=0x1ffc, m=0, id=20) / \ 111 sp.UDP(dport=3456, sport=6543) / \ 112 data 113 data = "6" * 8 114 ip6f02 = \ 115 sp.Ether() / \ 116 sp.IPv6(src=args.src[0], dst=args.to[0]) / \ 117 sp.IPv6ExtHdrDestOpt(options = \ 118 sp.PadN(optdata="\x00\x00\x00\x00\x00\x00")) / \ 119 sp.IPv6ExtHdrFragment(offset=0, m=1, id=20) / \ 120 sp.UDP(dport=3456, sport=6543) / \ 121 data 122 if args.debug : 123 ip6f00.display() 124 ip6f01.display() 125 ip6f02.display() 126 sp.sendp(ip6f00, iface=args.sendif[0], verbose=False) 127 sp.sendp(ip6f01, iface=args.sendif[0], verbose=False) 128 sp.sendp(ip6f02, iface=args.sendif[0], verbose=False) 129 130 sleep(75) 131 sniffer.setEnd() 132 sniffer.join() 133 if not sniffer.foundCorrectPacket: 134 sys.exit(1) 135 136 sys.exit(0) 137 138if __name__ == '__main__': 139 main() 140