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#!/usr/bin/env python
# Copyright (c) 2016 Cisco and/or its affiliates.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Router advertisement check script."""
import sys
import ipaddress
from scapy.layers.inet6 import IPv6, ICMPv6ND_RA, ICMPv6ND_NS
from resources.libraries.python.PacketVerifier import RxQueue
from resources.libraries.python.TrafficScriptArg import TrafficScriptArg
def mac_to_ipv6_linklocal(mac):
"""Transfer MAC address into specific link-local IPv6 address.
:param mac: MAC address to be transferred.
:type mac: str
:return: IPv6 link-local address.
:rtype: str
"""
# Remove the most common delimiters: dots, dashes, etc.
mac_value = int(mac.translate(None, ' .:-'), 16)
# Split out the bytes that slot into the IPv6 address
# XOR the most significant byte with 0x02, inverting the
# Universal / Local bit
high2 = mac_value >> 32 & 0xffff ^ 0x0200
high1 = mac_value >> 24 & 0xff
low1 = mac_value >> 16 & 0xff
low2 = mac_value & 0xffff
return 'fe80::{:04x}:{:02x}ff:fe{:02x}:{:04x}'.format(
high2, high1, low1, low2)
def main():
"""Check packets on specific port and look for the Router Advertisement
part.
"""
args = TrafficScriptArg(['src_mac', 'interval'])
rx_if = args.get_arg('rx_if')
src_mac = args.get_arg('src_mac')
interval = int(args.get_arg('interval'))
rxq = RxQueue(rx_if)
# receive ICMPv6ND_RA packet
while True:
ether = rxq.recv(max(5, interval))
if ether is None:
raise RuntimeError('ICMP echo Rx timeout')
if ether.haslayer(ICMPv6ND_NS):
# read another packet in the queue if the current one is ICMPv6ND_NS
continue
else:
# otherwise process the current packet
break
# Check if received packet contains layer RA and check other values
if not ether.haslayer(ICMPv6ND_RA):
raise RuntimeError('Not an RA packet received {0}'.
format(ether.__repr__()))
src_address = ipaddress.IPv6Address(unicode(ether['IPv6'].src))
dst_address = ipaddress.IPv6Address(unicode(ether['IPv6'].dst))
link_local = ipaddress.IPv6Address(unicode(mac_to_ipv6_linklocal(src_mac)))
all_nodes_multicast = ipaddress.IPv6Address(u'ff02::1')
if src_address != link_local:
raise RuntimeError('Source address ({0}) not matching link local '
'address ({1})'.format(src_address, link_local))
if dst_address != all_nodes_multicast:
raise RuntimeError('Packet destination address ({0}) is not the all'
' nodes multicast address ({1}).'.
format(dst_address, all_nodes_multicast))
if ether[IPv6].hlim != 255:
raise RuntimeError('Hop limit not correct: {0}!=255'.
format(ether[IPv6].hlim))
ra_code = ether[ICMPv6ND_RA].code
if ra_code != 0:
raise RuntimeError('ICMP code: {0} not correct. '.format(ra_code))
sys.exit(0)
if __name__ == "__main__":
main()
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