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Diffstat (limited to 'resources/libraries/python/PacketVerifier.py')
| -rw-r--r-- | resources/libraries/python/PacketVerifier.py | 310 |
1 files changed, 310 insertions, 0 deletions
diff --git a/resources/libraries/python/PacketVerifier.py b/resources/libraries/python/PacketVerifier.py new file mode 100644 index 0000000000..81798e1f68 --- /dev/null +++ b/resources/libraries/python/PacketVerifier.py @@ -0,0 +1,310 @@ +# 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. + +"""PacketVerifier module. + + :Example: + + >>> from scapy.all import * + >>> from PacketVerifier import * + >>> rxq = RxQueue('eth1') + >>> txq = TxQueue('eth1') + >>> src_mac = "AA:BB:CC:DD:EE:FF" + >>> dst_mac = "52:54:00:ca:5d:0b" + >>> src_ip = "11.11.11.10" + >>> dst_ip = "11.11.11.11" + >>> sent_packets = [] + >>> pkt_send = Ether(src=src_mac, dst=dst_mac) / + ... IP(src=src_ip, dst=dst_ip) / + ... ICMP() + >>> sent_packets.append(pkt_send) + >>> txq.send(pkt_send) + >>> pkt_send = Ether(src=src_mac, dst=dst_mac) / + ... ARP(hwsrc=src_mac, psrc=src_ip, hwdst=dst_mac, pdst=dst_ip, op=2) + >>> sent_packets.append(pkt_send) + >>> txq.send(pkt_send) + >>> rxq.recv(100, sent_packets).show() + ###[ Ethernet ]### + dst = aa:bb:cc:dd:ee:ff + src = 52:54:00:ca:5d:0b + type = 0x800 + ###[ IP ]### + version = 4L + ihl = 5L + tos = 0x0 + len = 28 + id = 43183 + flags = + frag = 0L + ttl = 64 + proto = icmp + chksum = 0xa607 + src = 11.11.11.11 + dst = 11.11.11.10 + \options \ + ###[ ICMP ]### + type = echo-reply + code = 0 + chksum = 0xffff + id = 0x0 + seq = 0x0 + ###[ Padding ]### + load = 'RT\x00\xca]\x0b\xaa\xbb\xcc\xdd\xee\xff\x08\x06\x00\x01\x08\x00' + >>> rxq._proc.terminate() +""" + + +import socket +import os +import time +from multiprocessing import Queue, Process +from scapy.all import ETH_P_IP, ETH_P_IPV6, ETH_P_ALL, ETH_P_ARP +from scapy.all import Ether, ARP, Packet +from scapy.layers.inet6 import IPv6 + +__all__ = ['RxQueue', 'TxQueue', 'Interface', 'create_gratuitous_arp_request', + 'auto_pad'] + +# TODO: http://stackoverflow.com/questions/320232/ensuring-subprocesses-are-dead-on-exiting-python-program + +class PacketVerifier(object): + """Base class for TX and RX queue objects for packet verifier.""" + def __init__(self, interface_name): + os.system('sudo echo 1 > /proc/sys/net/ipv6/conf/{0}/disable_ipv6' + .format(interface_name)) + os.system('sudo ip link set {0} up promisc on'.format(interface_name)) + self._sock = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, + ETH_P_ALL) + self._sock.bind((interface_name, ETH_P_ALL)) + + +def extract_one_packet(buf): + """Extract one packet from the incoming buf buffer. + + Takes string as input and looks for first whole packet in it. + If it finds one, it returns substring from the buf parameter. + + :param buf: string representation of incoming packet buffer. + :type buf: string + :return: String representation of first packet in buf. + :rtype: string + """ + pkt_len = 0 + + if len(buf) < 60: + return None + + # print + # print buf.__repr__() + # print Ether(buf).__repr__() + # print len(Ether(buf)) + # print + try: + ether_type = Ether(buf[0:14]).type + except AttributeError: + raise RuntimeError( + 'No EtherType in packet {0}'.format(buf.__repr__())) + + if ether_type == ETH_P_IP: + # 14 is Ethernet fame header size. + # 4 bytes is just enough to look for length in ip header. + # ip total length contains just the IP packet length so add the Ether + # header. + pkt_len = Ether(buf[0:14+4]).len + 14 + if len(buf) < 60: + return None + elif ether_type == ETH_P_IPV6: + if not Ether(buf[0:14+6]).haslayer(IPv6): + raise RuntimeError( + 'Invalid IPv6 packet {0}'.format(buf.__repr__())) + # ... to add to the above, 40 bytes is the length of IPV6 header. + # The ipv6.len only contains length of the payload and not the header + pkt_len = Ether(buf)['IPv6'].plen + 14 + 40 + if len(buf) < 60: + return None + elif ether_type == ETH_P_ARP: + pkt = Ether(buf[:20]) + if not pkt.haslayer(ARP): + raise RuntimeError('Incomplete ARP packet') + # len(eth) + arp(2 hw addr type + 2 proto addr type + # + 1b len + 1b len + 2b operation) + + pkt_len = 14 + 8 + pkt_len += 2 * pkt.getlayer(ARP).hwlen + pkt_len += 2 * pkt.getlayer(ARP).plen + + del pkt + elif ether_type == 32821: # RARP (Reverse ARP) + pkt = Ether(buf[:20]) + pkt.type = ETH_P_ARP # Change to ARP so it works with scapy + pkt = Ether(str(pkt)) + if not pkt.haslayer(ARP): + pkt.show() + raise RuntimeError('Incomplete RARP packet') + + # len(eth) + arp(2 hw addr type + 2 proto addr type + # + 1b len + 1b len + 2b operation) + pkt_len = 14 + 8 + pkt_len += 2 * pkt.getlayer(ARP).hwlen + pkt_len += 2 * pkt.getlayer(ARP).plen + + del pkt + else: + raise RuntimeError('Unknown protocol {0}'.format(ether_type)) + + if pkt_len < 60: + pkt_len = 60 + + if len(buf) < pkt_len: + return None + + return buf[0:pkt_len] + + +def packet_reader(interface_name, queue): + """Sub-process routine that reads packets and puts them to queue. + + This function is meant to be run in separate subprocess and is in tight + loop reading raw packets from interface passed as parameter. + + :param interace_name: Name of interface to read packets from. + :param queue: Queue in which this function will push incoming packets. + :type interface_name: string + :type queue: multiprocessing.Queue + :return: None + """ + sock = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, ETH_P_ALL) + sock.bind((interface_name, ETH_P_ALL)) + + buf = "" + while True: + recvd = sock.recv(1500) + buf = buf + recvd + + pkt = extract_one_packet(buf) + while pkt is not None: + if pkt is None: + break + queue.put(pkt) + buf = buf[len(pkt):] + pkt = extract_one_packet(buf) + + +class RxQueue(PacketVerifier): + """Receive queue object. + + This object creates raw socket, reads packets from it and provides + function to access them. + + :param interface_name: Which interface to bind to. + :type interface_name: string + """ + + def __init__(self, interface_name): + PacketVerifier.__init__(self, interface_name) + + self._queue = Queue() + self._proc = Process(target=packet_reader, args=(interface_name, + self._queue)) + self._proc.daemon = True + self._proc.start() + time.sleep(2) + + def recv(self, timeout=3, ignore=None): + """Read next received packet. + + Returns scapy's Ether() object created from next packet in the queue. + Queue is being filled in parallel in subprocess. If no packet + arrives in given timeout queue.Empty exception will be risen. + + :param timeout: How many seconds to wait for next packet. + :type timeout: int + + :return: Ether() initialized object from packet data. + :rtype: scapy.Ether + """ + + pkt = self._queue.get(True, timeout=timeout) + + if ignore is not None: + for i, ig_pkt in enumerate(ignore): + # Auto pad all packets in ignore list + ignore[i] = auto_pad(ig_pkt) + for ig_pkt in ignore: + if ig_pkt == pkt: + # Found the packet in ignore list, get another one + # TODO: subtract timeout - time_spent in here + ignore.remove(ig_pkt) + return self.recv(timeout, ignore) + + return Ether(pkt) + + +class TxQueue(PacketVerifier): + """Transmission queue object. + + This object is used to send packets over RAW socket on a interface. + + :param interface_name: Which interface to send packets from. + :type interface_name: string + """ + def __init__(self, interface_name): + PacketVerifier.__init__(self, interface_name) + + def send(self, pkt): + """Send packet out of the bound interface. + + :param pkt: Packet to send. + :type pkt: string or scapy Packet derivative. + """ + if isinstance(pkt, Packet): + pkt = str(pkt) + pkt = auto_pad(pkt) + self._sock.send(pkt) + + +class Interface(object): + def __init__(self, if_name): + self.if_name = if_name + self.sent_packets = [] + self.txq = TxQueue(if_name) + self.rxq = RxQueue(if_name) + + def send_pkt(self, pkt): + self.sent_packets.append(pkt) + self.txq.send(pkt) + + def recv_pkt(self, timeout=3): + while True: + pkt = self.rxq.recv(timeout, self.sent_packets) + # TODO: FIX FOLLOWING: DO NOT SKIP RARP IN ALL TESTS!!! + if pkt.type != 32821: # Skip RARP packets + return pkt + + def close(self): + self.rxq._proc.terminate() + + +def create_gratuitous_arp_request(src_mac, src_ip): + """Creates scapy representation of gratuitous ARP request""" + return (Ether(src=src_mac, dst='ff:ff:ff:ff:ff:ff') / + ARP(psrc=src_ip, hwsrc=src_mac, pdst=src_ip)) + + +def auto_pad(packet): + """Pads zeroes at the end of the packet if the total len < 60 bytes.""" + padded = str(packet) + if len(padded) < 60: + padded += ('\0' * (60 - len(padded))) + return padded + |