#!/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_WINDOW = 14400 PTB_MTU = 1280 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, 5: 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, lifetime=39): if version == 4: packet = (scapy.IP(src=srcaddr, dst=dstaddr, ttl=lifetime, tos=0x83) / scapy.UDP(sport=sport, dport=53) / UDP_PAYLOAD) else: packet = (scapy.IPv6(src=srcaddr, dst=dstaddr, fl=0xbeef, hlim=lifetime, 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=-1): ip = _GetIpLayer(version) if sport == 0: sport = _RandomPort() if seq == -1: # Can't use None because it means unspecified. seq = random.getrandbits(32) 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=original.ack, 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: desc = "ICMPv4 fragmentation needed" pkt = (scapy.IP(src=srcaddr, dst=dstaddr, proto=1) / scapy.ICMPerror(type=3, code=4) / str(packet)[:64]) # Only newer versions of scapy understand that since RFC 1191, the last two # bytes of a fragmentation needed ICMP error contain the MTU. if hasattr(scapy.ICMP, "nexthopmtu"): pkt[scapy.ICMPerror].nexthopmtu = PTB_MTU else: pkt[scapy.ICMPerror].unused = PTB_MTU return desc, pkt else: return ("ICMPv6 Packet Too Big", scapy.IPv6(src=srcaddr, dst=dstaddr) / scapy.ICMPv6PacketTooBig(mtu=PTB_MTU) / 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)