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#!/usr/bin/env python3
# Copyright (c) 2020 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.
"""Traffic script for IPsec verification."""
import sys
from ipaddress import ip_address
from scapy.layers.inet import IP
from scapy.layers.inet6 import IPv6, ICMPv6ND_NS
from scapy.layers.ipsec import SecurityAssociation, ESP
from scapy.layers.l2 import Ether
from scapy.packet import Raw
from resources.libraries.python.PacketVerifier import RxQueue, TxQueue
from resources.libraries.python.TrafficScriptArg import TrafficScriptArg
def check_ipsec(
pkt_recv, ip_layer, src_mac, dst_mac, src_tun, dst_tun, src_ip, dst_ip,
sa_in):
"""Check received IPsec packet.
:param pkt_recv: Received packet to verify.
:param ip_layer: Scapy IP layer.
:param src_mac: Source MAC address.
:param dst_mac: Destination MAC address.
:param src_tun: IPsec tunnel source address.
:param dst_tun: IPsec tunnel destination address.
:param src_ip: Source IP/IPv6 address of original IP/IPv6 packet.
:param dst_ip: Destination IP/IPv6 address of original IP/IPv6 packet.
:param sa_in: IPsec SA for packet decryption.
:type pkt_recv: scapy.Ether
:type ip_layer: scapy.layers.inet.IP or scapy.layers.inet6.IPv6
:type src_mac: str
:type dst_mac: str
:type src_tun: str
:type dst_tun: str
:type src_ip: str
:type dst_ip: str
:type sa_in: scapy.layers.ipsec.SecurityAssociation
:raises RuntimeError: If received packet is invalid.
"""
if pkt_recv[Ether].src != src_mac:
raise RuntimeError(
f"Received frame has invalid source MAC address: "
f"{pkt_recv[Ether].src} should be: {src_mac}"
)
if pkt_recv[Ether].dst != dst_mac:
raise RuntimeError(
f"Received frame has invalid destination MAC address: "
f"{pkt_recv[Ether].dst} should be: {dst_mac}"
)
if not pkt_recv.haslayer(ip_layer):
raise RuntimeError(
f"Not an {ip_layer.name} packet received: {pkt_recv!r}"
)
if pkt_recv[ip_layer].src != src_tun:
raise RuntimeError(
f"Received packet has invalid source address: "
f"{pkt_recv[ip_layer].src} should be: {src_tun}"
)
if pkt_recv[ip_layer].dst != dst_tun:
raise RuntimeError(
f"Received packet has invalid destination address: "
f"{pkt_recv[ip_layer].dst} should be: {dst_tun}"
)
if not pkt_recv.haslayer(ESP):
raise RuntimeError(f"Not an ESP packet received: {pkt_recv!r}")
ip_pkt = pkt_recv[ip_layer]
d_pkt = sa_in.decrypt(ip_pkt)
if d_pkt[ip_layer].dst != dst_ip:
raise RuntimeError(
f"Decrypted packet has invalid destination address: "
f"{d_pkt[ip_layer].dst} should be: {dst_ip}"
)
if d_pkt[ip_layer].src != src_ip:
raise RuntimeError(
f"Decrypted packet has invalid source address: "
f"{d_pkt[ip_layer].src} should be: {src_ip}"
)
if ip_layer == IP and d_pkt[ip_layer].proto != 61:
raise RuntimeError(
f"Decrypted packet has invalid IP protocol: "
f"{d_pkt[ip_layer].proto} should be: 61"
)
def check_ip(pkt_recv, ip_layer, src_mac, dst_mac, src_ip, dst_ip):
"""Check received IP/IPv6 packet.
:param pkt_recv: Received packet to verify.
:param ip_layer: Scapy IP layer.
:param src_mac: Source MAC address.
:param dst_mac: Destination MAC address.
:param src_ip: Source IP/IPv6 address.
:param dst_ip: Destination IP/IPv6 address.
:type pkt_recv: scapy.Ether
:type ip_layer: scapy.layers.inet.IP or scapy.layers.inet6.IPv6
:type src_mac: str
:type dst_mac: str
:type src_ip: str
:type dst_ip: str
:raises RuntimeError: If received packet is invalid.
"""
if pkt_recv[Ether].src != src_mac:
raise RuntimeError(
f"Received frame has invalid source MAC address: "
f"{pkt_recv[Ether].src} should be: {src_mac}"
)
if pkt_recv[Ether].dst != dst_mac:
raise RuntimeError(
f"Received frame has invalid destination MAC address: "
f"{pkt_recv[Ether].dst} should be: {dst_mac}"
)
if not pkt_recv.haslayer(ip_layer):
raise RuntimeError(
f"Not an {ip_layer.name} packet received: {pkt_recv!r}"
)
if pkt_recv[ip_layer].dst != dst_ip:
raise RuntimeError(
f"Received packet has invalid destination address: "
f"{pkt_recv[ip_layer.name].dst} should be: {dst_ip}"
)
if pkt_recv[ip_layer].src != src_ip:
raise RuntimeError(
f"Received packet has invalid destination address: "
f"{pkt_recv[ip_layer.name].dst} should be: {src_ip}"
)
if ip_layer == IP and pkt_recv[ip_layer].proto != 61:
raise RuntimeError(
f"Received packet has invalid IP protocol: "
f"{pkt_recv[ip_layer].proto} should be: 61"
)
def main():
"""Send and receive IPsec packet."""
args = TrafficScriptArg(
[
u"tx_src_mac", u"tx_dst_mac", u"rx_src_mac", u"rx_dst_mac",
u"src_ip", u"dst_ip", u"src_tun", u"dst_tun", u"crypto_alg",
u"crypto_key", u"integ_alg", u"integ_key", u"l_spi", u"r_spi"
]
)
tx_txq = TxQueue(args.get_arg(u"tx_if"))
tx_rxq = RxQueue(args.get_arg(u"tx_if"))
rx_txq = TxQueue(args.get_arg(u"rx_if"))
rx_rxq = RxQueue(args.get_arg(u"rx_if"))
tx_src_mac = args.get_arg(u"tx_src_mac")
tx_dst_mac = args.get_arg(u"tx_dst_mac")
rx_src_mac = args.get_arg(u"rx_src_mac")
rx_dst_mac = args.get_arg(u"rx_dst_mac")
src_ip = args.get_arg(u"src_ip")
dst_ip = args.get_arg(u"dst_ip")
src_tun = args.get_arg(u"src_tun")
dst_tun = args.get_arg(u"dst_tun")
crypto_alg = args.get_arg(u"crypto_alg")
crypto_key = args.get_arg(u"crypto_key")
integ_alg = args.get_arg(u"integ_alg")
integ_key = args.get_arg(u"integ_key")
l_spi = int(args.get_arg(u"l_spi"))
r_spi = int(args.get_arg(u"r_spi"))
ip_layer = IP if ip_address(src_ip).version == 4 else IPv6
ip_pkt = ip_layer(src=src_ip, dst=dst_ip, proto=61) if ip_layer == IP \
else ip_layer(src=src_ip, dst=dst_ip)
tunnel_in = ip_layer(src=src_tun, dst=dst_tun)
tunnel_out = ip_layer(src=dst_tun, dst=src_tun)
sa_in = SecurityAssociation(
ESP, spi=l_spi, crypt_algo=crypto_alg,
crypt_key=crypto_key.encode(encoding=u"utf-8"), auth_algo=integ_alg,
auth_key=integ_key.encode(encoding=u"utf-8"),
tunnel_header=tunnel_in
)
sa_out = SecurityAssociation(
ESP, spi=r_spi, crypt_algo=crypto_alg,
crypt_key=crypto_key.encode(encoding=u"utf-8"), auth_algo=integ_alg,
auth_key=integ_key.encode(encoding=u"utf-8"),
tunnel_header=tunnel_out
)
sent_packets = list()
tx_pkt_send = (Ether(src=tx_src_mac, dst=tx_dst_mac) / ip_pkt)
tx_pkt_send /= Raw()
size_limit = 78 if ip_layer == IPv6 else 64
if len(tx_pkt_send) < size_limit:
tx_pkt_send[Raw].load += (b"\0" * (size_limit - len(tx_pkt_send)))
sent_packets.append(tx_pkt_send)
tx_txq.send(tx_pkt_send)
while True:
rx_pkt_recv = rx_rxq.recv(2)
if rx_pkt_recv is None:
raise RuntimeError(f"{ip_layer.name} packet Rx timeout")
if rx_pkt_recv.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_ipsec(
rx_pkt_recv, ip_layer, rx_src_mac, rx_dst_mac, src_tun, dst_tun, src_ip,
dst_ip, sa_in
)
ip_pkt = ip_layer(src=dst_ip, dst=src_ip, proto=61) if ip_layer == IP \
else ip_layer(src=dst_ip, dst=src_ip)
ip_pkt /= Raw()
if len(ip_pkt) < (size_limit - 14):
ip_pkt[Raw].load += (b"\0" * (size_limit - 14 - len(ip_pkt)))
e_pkt = sa_out.encrypt(ip_pkt)
rx_pkt_send = (Ether(src=rx_dst_mac, dst=rx_src_mac) /
e_pkt)
rx_txq.send(rx_pkt_send)
while True:
tx_pkt_recv = tx_rxq.recv(2, ignore=sent_packets)
if tx_pkt_recv is None:
raise RuntimeError(f"{ip_layer.name} packet Rx timeout")
if tx_pkt_recv.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_ip(tx_pkt_recv, ip_layer, tx_dst_mac, tx_src_mac, dst_ip, src_ip)
sys.exit(0)
if __name__ == u"__main__":
main()
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