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 scapy.all as sp 33import socket 34import sys 35from sniffer import Sniffer 36from time import sleep 37 38def check_icmp6_error(args, packet): 39 ip6 = packet.getlayer(sp.IPv6) 40 if not ip6: 41 return False 42 oip6 = sp.IPv6(src=args.src[0], dst=args.to[0]) 43 if ip6.dst != oip6.src: 44 return False 45 icmp6 = packet.getlayer(sp.ICMPv6TimeExceeded) 46 if not icmp6: 47 return False 48 # ICMP6_TIME_EXCEED_REASSEMBLY 1 49 if icmp6.code != 1: 50 return False 51 # Should we check the payload as well? 52 # We are running in a very isolated environment and nothing else 53 # should trigger an ICMPv6 Time Exceeded / Frag reassembly so leave it. 54 #icmp6.display() 55 return True 56 57 58def main(): 59 parser = argparse.ArgumentParser("frag6.py", 60 description="IPv6 fragementation test tool") 61 parser.add_argument('--sendif', nargs=1, 62 required=True, 63 help='The interface through which the packet will be sent') 64 parser.add_argument('--recvif', nargs=1, 65 required=True, 66 help='The interface on which to check for the packet') 67 parser.add_argument('--src', nargs=1, 68 required=True, 69 help='The source IP address') 70 parser.add_argument('--to', nargs=1, 71 required=True, 72 help='The destination IP address') 73 parser.add_argument('--debug', 74 required=False, action='store_true', 75 help='Enable test debugging') 76 77 args = parser.parse_args() 78 79 80 # Start sniffing on recvif 81 sniffer = Sniffer(args, check_icmp6_error) 82 83 84 ######################################################################## 85 # 86 # Send a proper first fragment (off=0) and a second fragment which 87 # just fits the 64k. The re-send the first fragment with an extra 88 # unfragmentable part making the 64k to exceed the limit. 89 # This is to make sure we don't allow to update meta-data for a 90 # 1st fragmented packet should a second arrive but given the 91 # fragmentable part is an exact duplicate only that fragment 92 # will be silently discarded. 93 # 94 # A: Reassembly failure, timeout after 95 # R: ICMPv6 time exceeded / statistics for the duplicate 96 # 97 data = "6" * 8 98 ip6f00 = \ 99 sp.Ether() / \ 100 sp.IPv6(src=args.src[0], dst=args.to[0]) / \ 101 sp.IPv6ExtHdrFragment(offset=0, m=1, id=20) / \ 102 sp.UDP(dport=3456, sport=6543) / \ 103 data 104 data = "6" * 15 105 ip6f01 = \ 106 sp.Ether() / \ 107 sp.IPv6(src=args.src[0], dst=args.to[0]) / \ 108 sp.IPv6ExtHdrFragment(offset=0x1ffc, m=0, id=20) / \ 109 sp.UDP(dport=3456, sport=6543) / \ 110 data 111 data = "6" * 8 112 ip6f02 = \ 113 sp.Ether() / \ 114 sp.IPv6(src=args.src[0], dst=args.to[0]) / \ 115 sp.IPv6ExtHdrDestOpt(options = \ 116 sp.PadN(optdata="\x00\x00\x00\x00\x00\x00")) / \ 117 sp.IPv6ExtHdrFragment(offset=0, m=1, id=20) / \ 118 sp.UDP(dport=3456, sport=6543) / \ 119 data 120 if args.debug : 121 ip6f00.display() 122 ip6f01.display() 123 ip6f02.display() 124 sp.sendp(ip6f00, iface=args.sendif[0], verbose=False) 125 sp.sendp(ip6f01, iface=args.sendif[0], verbose=False) 126 sp.sendp(ip6f02, iface=args.sendif[0], verbose=False) 127 128 sleep(75) 129 sniffer.setEnd() 130 sniffer.join() 131 if not sniffer.foundCorrectPacket: 132 sys.exit(1) 133 134 sys.exit(0) 135 136if __name__ == '__main__': 137 main() 138