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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 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'])
rx_if = args.get_arg('rx_if')
src_mac = args.get_arg('src_mac')
rxq = RxQueue(rx_if)
ether = rxq.recv(8)
# Check whether received packet contains layer RA and check other values
if ether is None:
raise RuntimeError('ICMP echo Rx timeout')
if not ether.haslayer('ICMPv6ND_RA'):
raise RuntimeError('Not an RA packet received {0}'
.format(ether.__repr__()))
address = ipaddress.IPv6Address(unicode(ether['IPv6'].src))
link_local = ipaddress.IPv6Address(unicode(mac_to_ipv6_linklocal(src_mac)))
if address != link_local:
raise RuntimeError(
'Source address ({0}) not matching link local address({1})'.format(
address, link_local))
if ether['IPv6'].hlim != 255:
raise RuntimeError('Hop limit not correct: {0}!=255'.format(
ether['IPv6'].hlim))
ra_code = ether['ICMPv6 Neighbor Discovery - Router Advertisement'].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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