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# 29 30import argparse 31import logging 32logging.getLogger("scapy").setLevel(logging.CRITICAL) 33import scapy.all as sp 34import socket 35import sys 36from sniffer import Sniffer 37from time import sleep 38 39def check_icmp6_error(args, packet): 40 ip6 = packet.getlayer(sp.IPv6) 41 if not ip6: 42 return False 43 oip6 = sp.IPv6(src=args.src[0], dst=args.to[0]) 44 if ip6.dst != oip6.src: 45 return False 46 icmp6 = packet.getlayer(sp.ICMPv6TimeExceeded) 47 if not icmp6: 48 return False 49 # ICMP6_TIME_EXCEED_REASSEMBLY 1 50 if icmp6.code != 1: 51 return False 52 # Should we check the payload as well? 53 # We are running in a very isolated environment and nothing else 54 # should trigger an ICMPv6 Time Exceeded / Frag reassembly so leave it. 55 #icmp6.display() 56 return True 57 58 59def main(): 60 parser = argparse.ArgumentParser("frag6.py", 61 description="IPv6 fragementation test tool") 62 parser.add_argument('--sendif', nargs=1, 63 required=True, 64 help='The interface through which the packet will be sent') 65 parser.add_argument('--recvif', nargs=1, 66 required=True, 67 help='The interface on which to check for the packet') 68 parser.add_argument('--src', nargs=1, 69 required=True, 70 help='The source IP address') 71 parser.add_argument('--to', nargs=1, 72 required=True, 73 help='The destination IP address') 74 parser.add_argument('--debug', 75 required=False, action='store_true', 76 help='Enable test debugging') 77 78 args = parser.parse_args() 79 80 81 # Start sniffing on recvif 82 sniffer = Sniffer(args, check_icmp6_error) 83 84 85 ######################################################################## 86 # 87 # Send a proper first fragment (off=0) and a second fragment which 88 # just fits the 64k. The re-send the first fragment with an extra 89 # unfragmentable part making the 64k to exceed the limit. 90 # This is to make sure we don't allow to update meta-data for a 91 # 1st fragmented packet should a second arrive but given the 92 # fragmentable part is an exact duplicate only that fragment 93 # will be silently discarded. 94 # 95 # A: Reassembly failure, timeout after 96 # R: ICMPv6 time exceeded / statistics for the duplicate 97 # 98 data = "6" * 8 99 ip6f00 = \ 100 sp.Ether() / \ 101 sp.IPv6(src=args.src[0], dst=args.to[0]) / \ 102 sp.IPv6ExtHdrFragment(offset=0, m=1, id=20) / \ 103 sp.UDP(dport=3456, sport=6543) / \ 104 data 105 data = "6" * 15 106 ip6f01 = \ 107 sp.Ether() / \ 108 sp.IPv6(src=args.src[0], dst=args.to[0]) / \ 109 sp.IPv6ExtHdrFragment(offset=0x1ffc, m=0, id=20) / \ 110 sp.UDP(dport=3456, sport=6543) / \ 111 data 112 data = "6" * 8 113 ip6f02 = \ 114 sp.Ether() / \ 115 sp.IPv6(src=args.src[0], dst=args.to[0]) / \ 116 sp.IPv6ExtHdrDestOpt(options = \ 117 sp.PadN(optdata="\x00\x00\x00\x00\x00\x00")) / \ 118 sp.IPv6ExtHdrFragment(offset=0, m=1, id=20) / \ 119 sp.UDP(dport=3456, sport=6543) / \ 120 data 121 if args.debug : 122 ip6f00.display() 123 ip6f01.display() 124 ip6f02.display() 125 sp.sendp(ip6f00, iface=args.sendif[0], verbose=False) 126 sp.sendp(ip6f01, iface=args.sendif[0], verbose=False) 127 sp.sendp(ip6f02, iface=args.sendif[0], verbose=False) 128 129 sleep(3) 130 sniffer.setEnd() 131 sniffer.join() 132 if not sniffer.foundCorrectPacket: 133 sys.exit(1) 134 135 sys.exit(0) 136 137if __name__ == '__main__': 138 main() 139