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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.
from scapy.all import Ether, IP, ICMP
from resources.libraries.python.PacketVerifier \
import Interface, create_gratuitous_arp_request, auto_pad, checksum_equal
from resources.libraries.python.TrafficScriptArg import TrafficScriptArg
def check_ttl(ttl_begin, ttl_end, ttl_diff):
if ttl_begin != ttl_end + ttl_diff:
raise RuntimeError(
"TTL changed from {} to {} but decrease by {} expected"
.format(ttl_begin, ttl_end, ttl_diff))
def ckeck_packets_equal(pkt_send, pkt_recv):
pkt_send_raw = auto_pad(pkt_send)
pkt_recv_raw = auto_pad(pkt_recv)
if pkt_send_raw != pkt_recv_raw:
print "Sent: {}".format(pkt_send_raw.encode('hex'))
print "Received: {}".format(pkt_recv_raw.encode('hex'))
print "Sent:"
pkt_send.show2()
print "Received:"
pkt_recv.show2()
raise RuntimeError("Sent packet doesn't match received packet")
def main():
args = TrafficScriptArg(['src_mac', 'dst_mac', 'src_ip', 'dst_ip',
'hops', 'first_hop_mac', 'is_dst_tg'])
src_if_name = args.get_arg('tx_if')
dst_if_name = args.get_arg('rx_if')
is_dst_tg = True if args.get_arg('is_dst_tg') == 'True' else False
src_mac = args.get_arg('src_mac')
first_hop_mac = args.get_arg('first_hop_mac')
dst_mac = args.get_arg('dst_mac')
src_ip = args.get_arg('src_ip')
dst_ip = args.get_arg('dst_ip')
hops = int(args.get_arg('hops'))
if is_dst_tg and (src_if_name == dst_if_name):
raise RuntimeError(
"Source interface name equals destination interface name")
src_if = Interface(src_if_name)
src_if.send_pkt(str(create_gratuitous_arp_request(src_mac, src_ip)))
if is_dst_tg:
dst_if = Interface(dst_if_name)
dst_if.send_pkt(str(create_gratuitous_arp_request(dst_mac, dst_ip)))
pkt_req_send = (Ether(src=src_mac, dst=first_hop_mac) /
IP(src=src_ip, dst=dst_ip) /
ICMP())
src_if.send_pkt(pkt_req_send)
if is_dst_tg:
pkt_req_recv = dst_if.recv_pkt()
if pkt_req_recv is None:
raise RuntimeError('Timeout waiting for packet')
check_ttl(pkt_req_send[IP].ttl, pkt_req_recv[IP].ttl, hops)
pkt_req_send_mod = pkt_req_send.copy()
pkt_req_send_mod[IP].ttl = pkt_req_recv[IP].ttl
del pkt_req_send_mod[IP].chksum # update checksum
ckeck_packets_equal(pkt_req_send_mod[IP], pkt_req_recv[IP])
pkt_resp_send = (Ether(src=dst_mac, dst=pkt_req_recv.src) /
IP(src=dst_ip, dst=src_ip) /
ICMP(type=0)) # echo-reply
dst_if.send_pkt(pkt_resp_send)
pkt_resp_recv = src_if.recv_pkt()
if pkt_resp_recv is None:
raise RuntimeError('Timeout waiting for packet')
if is_dst_tg:
check_ttl(pkt_resp_send[IP].ttl, pkt_resp_recv[IP].ttl, hops)
pkt_resp_send_mod = pkt_resp_send.copy()
pkt_resp_send_mod[IP].ttl = pkt_resp_recv[IP].ttl
del pkt_resp_send_mod[IP].chksum # update checksum
ckeck_packets_equal(pkt_resp_send_mod[IP], pkt_resp_recv[IP])
if not pkt_resp_recv.haslayer(IP):
raise RuntimeError('Received packet does not contain IPv4 header: {}'.
format(pkt_resp_recv.__repr__()))
if pkt_resp_recv[IP].src != pkt_req_send[IP].dst:
raise RuntimeError(
'Received IPv4 packet contains wrong src IP address, '
'{} instead of {}'.format(pkt_resp_recv[IP].src,
pkt_req_send[IP].dst))
if pkt_resp_recv[IP].dst != pkt_req_send[IP].src:
raise RuntimeError(
'Received IPv4 packet contains wrong dst IP address, '
'{} instead of {}'.format(pkt_resp_recv[IP].dst,
pkt_req_send[IP].src))
# verify IPv4 checksum
copy = pkt_resp_recv.copy()
chksum = copy[IP].chksum
del copy[IP].chksum
tmp = IP(str(copy[IP]))
if not checksum_equal(tmp.chksum, chksum):
raise RuntimeError('Received IPv4 packet contains invalid checksum, '
'{} instead of {}'.format(chksum, tmp.chksum))
if not pkt_resp_recv[IP].haslayer(ICMP):
raise RuntimeError(
'Received IPv4 packet does not contain ICMP header: {}'.
format(pkt_resp_recv[IP].__repr__()))
# verify ICMP checksum
copy = pkt_resp_recv.copy()
chksum = copy[IP][ICMP].chksum
del copy[IP][ICMP].chksum
tmp = ICMP(str(copy[IP][ICMP]))
if not checksum_equal(tmp.chksum, chksum):
raise RuntimeError('Received ICMP packet contains invalid checksum, '
'{} instead of {}'.format(chksum, tmp.chksum))
pkt_req_send_mod = pkt_req_send.copy()
pkt_req_send_mod[IP][ICMP].type = pkt_resp_recv[IP][ICMP].type
del pkt_req_send_mod[IP][ICMP].chksum # update checksum
ckeck_packets_equal(pkt_req_send_mod[IP][ICMP], pkt_resp_recv[IP][ICMP])
if __name__ == "__main__":
main()
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