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#!/usr/bin/python
#
# Copyright 2015 The Android Open Source Project
#
# 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.
import random
from scapy import all as scapy
from socket import *
import net_test
TCP_FIN = 1
TCP_SYN = 2
TCP_RST = 4
TCP_PSH = 8
TCP_ACK = 16
TCP_SEQ = 1692871236
TCP_WINDOW = 14400
PING_IDENT = 0xff19
PING_PAYLOAD = "foobarbaz"
PING_SEQ = 3
PING_TOS = 0x83
# For brevity.
UDP_PAYLOAD = net_test.UDP_PAYLOAD
def RandomPort():
return random.randint(1025, 65535)
def _GetIpLayer(version):
return {4: scapy.IP, 6: scapy.IPv6}[version]
def _SetPacketTos(packet, tos):
if isinstance(packet, scapy.IPv6):
packet.tc = tos
elif isinstance(packet, scapy.IP):
packet.tos = tos
else:
raise ValueError("Can't find ToS Field")
def UDP(version, srcaddr, dstaddr, sport=0):
ip = _GetIpLayer(version)
# Can't just use "if sport" because None has meaning (it means unspecified).
if sport == 0:
sport = RandomPort()
return ("UDPv%d packet" % version,
ip(src=srcaddr, dst=dstaddr) /
scapy.UDP(sport=sport, dport=53) / UDP_PAYLOAD)
def UDPWithOptions(version, srcaddr, dstaddr, sport=0):
if version == 4:
packet = (scapy.IP(src=srcaddr, dst=dstaddr, ttl=39, tos=0x83) /
scapy.UDP(sport=sport, dport=53) /
UDP_PAYLOAD)
else:
packet = (scapy.IPv6(src=srcaddr, dst=dstaddr,
fl=0xbeef, hlim=39, tc=0x83) /
scapy.UDP(sport=sport, dport=53) /
UDP_PAYLOAD)
return ("UDPv%d packet with options" % version, packet)
def SYN(dport, version, srcaddr, dstaddr, sport=0, seq=TCP_SEQ):
ip = _GetIpLayer(version)
if sport == 0:
sport = RandomPort()
return ("TCP SYN",
ip(src=srcaddr, dst=dstaddr) /
scapy.TCP(sport=sport, dport=dport,
seq=seq, ack=0,
flags=TCP_SYN, window=TCP_WINDOW))
def RST(version, srcaddr, dstaddr, packet):
ip = _GetIpLayer(version)
original = packet.getlayer("TCP")
was_syn_or_fin = (original.flags & (TCP_SYN | TCP_FIN)) != 0
return ("TCP RST",
ip(src=srcaddr, dst=dstaddr) /
scapy.TCP(sport=original.dport, dport=original.sport,
ack=original.seq + was_syn_or_fin, seq=None,
flags=TCP_RST | TCP_ACK, window=TCP_WINDOW))
def SYNACK(version, srcaddr, dstaddr, packet):
ip = _GetIpLayer(version)
original = packet.getlayer("TCP")
return ("TCP SYN+ACK",
ip(src=srcaddr, dst=dstaddr) /
scapy.TCP(sport=original.dport, dport=original.sport,
ack=original.seq + 1, seq=None,
flags=TCP_SYN | TCP_ACK, window=None))
def ACK(version, srcaddr, dstaddr, packet, payload=""):
ip = _GetIpLayer(version)
original = packet.getlayer("TCP")
was_syn_or_fin = (original.flags & (TCP_SYN | TCP_FIN)) != 0
ack_delta = was_syn_or_fin + len(original.payload)
desc = "TCP data" if payload else "TCP ACK"
flags = TCP_ACK | TCP_PSH if payload else TCP_ACK
return (desc,
ip(src=srcaddr, dst=dstaddr) /
scapy.TCP(sport=original.dport, dport=original.sport,
ack=original.seq + ack_delta, seq=original.ack,
flags=flags, window=TCP_WINDOW) /
payload)
def FIN(version, srcaddr, dstaddr, packet):
ip = _GetIpLayer(version)
original = packet.getlayer("TCP")
was_syn_or_fin = (original.flags & (TCP_SYN | TCP_FIN)) != 0
ack_delta = was_syn_or_fin + len(original.payload)
return ("TCP FIN",
ip(src=srcaddr, dst=dstaddr) /
scapy.TCP(sport=original.dport, dport=original.sport,
ack=original.seq + ack_delta, seq=original.ack,
flags=TCP_ACK | TCP_FIN, window=TCP_WINDOW))
def GRE(version, srcaddr, dstaddr, proto, packet):
if version == 4:
ip = scapy.IP(src=srcaddr, dst=dstaddr, proto=net_test.IPPROTO_GRE)
else:
ip = scapy.IPv6(src=srcaddr, dst=dstaddr, nh=net_test.IPPROTO_GRE)
packet = ip / scapy.GRE(proto=proto) / packet
return ("GRE packet", packet)
def ICMPPortUnreachable(version, srcaddr, dstaddr, packet):
if version == 4:
# Linux hardcodes the ToS on ICMP errors to 0xc0 or greater because of
# RFC 1812 4.3.2.5 (!).
return ("ICMPv4 port unreachable",
scapy.IP(src=srcaddr, dst=dstaddr, proto=1, tos=0xc0) /
scapy.ICMPerror(type=3, code=3) / packet)
else:
return ("ICMPv6 port unreachable",
scapy.IPv6(src=srcaddr, dst=dstaddr) /
scapy.ICMPv6DestUnreach(code=4) / packet)
def ICMPPacketTooBig(version, srcaddr, dstaddr, packet):
if version == 4:
return ("ICMPv4 fragmentation needed",
scapy.IP(src=srcaddr, dst=dstaddr, proto=1) /
scapy.ICMPerror(type=3, code=4, unused=1280) / str(packet)[:64])
else:
udp = packet.getlayer("UDP")
udp.payload = str(udp.payload)[:1280-40-8]
return ("ICMPv6 Packet Too Big",
scapy.IPv6(src=srcaddr, dst=dstaddr) /
scapy.ICMPv6PacketTooBig() / str(packet)[:1232])
def ICMPEcho(version, srcaddr, dstaddr):
ip = _GetIpLayer(version)
icmp = {4: scapy.ICMP, 6: scapy.ICMPv6EchoRequest}[version]
packet = (ip(src=srcaddr, dst=dstaddr) /
icmp(id=PING_IDENT, seq=PING_SEQ) / PING_PAYLOAD)
_SetPacketTos(packet, PING_TOS)
return ("ICMPv%d echo" % version, packet)
def ICMPReply(version, srcaddr, dstaddr, packet):
ip = _GetIpLayer(version)
# Scapy doesn't provide an ICMP echo reply constructor.
icmpv4_reply = lambda **kwargs: scapy.ICMP(type=0, **kwargs)
icmp = {4: icmpv4_reply, 6: scapy.ICMPv6EchoReply}[version]
packet = (ip(src=srcaddr, dst=dstaddr) /
icmp(id=PING_IDENT, seq=PING_SEQ) / PING_PAYLOAD)
# IPv6 only started copying the tclass to echo replies in 3.14.
if version == 4 or net_test.LINUX_VERSION >= (3, 14):
_SetPacketTos(packet, PING_TOS)
return ("ICMPv%d echo reply" % version, packet)
def NS(srcaddr, tgtaddr, srcmac):
solicited = inet_pton(AF_INET6, tgtaddr)
last3bytes = tuple([ord(b) for b in solicited[-3:]])
solicited = "ff02::1:ff%02x:%02x%02x" % last3bytes
packet = (scapy.IPv6(src=srcaddr, dst=solicited) /
scapy.ICMPv6ND_NS(tgt=tgtaddr) /
scapy.ICMPv6NDOptSrcLLAddr(lladdr=srcmac))
return ("ICMPv6 NS", packet)
def NA(srcaddr, dstaddr, srcmac):
packet = (scapy.IPv6(src=srcaddr, dst=dstaddr) /
scapy.ICMPv6ND_NA(tgt=srcaddr, R=0, S=1, O=1) /
scapy.ICMPv6NDOptDstLLAddr(lladdr=srcmac))
return ("ICMPv6 NA", packet)
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