1 # Copyright (c) 2016 Cisco and/or its affiliates.
2 # Licensed under the Apache License, Version 2.0 (the "License");
3 # you may not use this file except in compliance with the License.
4 # You may obtain a copy of the License at:
6 # http://www.apache.org/licenses/LICENSE-2.0
8 # Unless required by applicable law or agreed to in writing, software
9 # distributed under the License is distributed on an "AS IS" BASIS,
10 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 # See the License for the specific language governing permissions and
12 # limitations under the License.
14 """PacketVerifier module.
18 >>> from scapy.all import *
19 >>> from PacketVerifier import *
20 >>> rxq = RxQueue('eth1')
21 >>> txq = TxQueue('eth1')
22 >>> src_mac = "AA:BB:CC:DD:EE:FF"
23 >>> dst_mac = "52:54:00:ca:5d:0b"
24 >>> src_ip = "11.11.11.10"
25 >>> dst_ip = "11.11.11.11"
27 >>> pkt_send = Ether(src=src_mac, dst=dst_mac) /
28 ... IP(src=src_ip, dst=dst_ip) /
30 >>> sent_packets.append(pkt_send)
31 >>> txq.send(pkt_send)
32 >>> pkt_send = Ether(src=src_mac, dst=dst_mac) /
33 ... ARP(hwsrc=src_mac, psrc=src_ip, hwdst=dst_mac, pdst=dst_ip, op=2)
34 >>> sent_packets.append(pkt_send)
35 >>> txq.send(pkt_send)
36 >>> rxq.recv(100, sent_packets).show()
38 dst = aa:bb:cc:dd:ee:ff
39 src = 52:54:00:ca:5d:0b
62 load = 'RT\x00\xca]\x0b\xaa\xbb\xcc\xdd\xee\xff\x08\x06\x00\x01\x08\x00'
70 from multiprocessing import Queue, Process
71 from scapy.all import ETH_P_IP, ETH_P_IPV6, ETH_P_ALL, ETH_P_ARP
72 from scapy.all import Ether, ARP, Packet
73 from scapy.layers.inet6 import IPv6
75 __all__ = ['RxQueue', 'TxQueue', 'Interface', 'create_gratuitous_arp_request',
78 # TODO: http://stackoverflow.com/questions/320232/ensuring-subprocesses-are-dead-on-exiting-python-program
80 class PacketVerifier(object):
81 """Base class for TX and RX queue objects for packet verifier."""
82 def __init__(self, interface_name):
83 os.system('sudo echo 1 > /proc/sys/net/ipv6/conf/{0}/disable_ipv6'
84 .format(interface_name))
85 os.system('sudo ip link set {0} up promisc on'.format(interface_name))
86 self._sock = socket.socket(socket.AF_PACKET, socket.SOCK_RAW,
88 self._sock.bind((interface_name, ETH_P_ALL))
89 self._ifname = interface_name
92 def extract_one_packet(buf):
93 """Extract one packet from the incoming buf buffer.
95 Takes string as input and looks for first whole packet in it.
96 If it finds one, it returns substring from the buf parameter.
98 :param buf: string representation of incoming packet buffer.
100 :return: String representation of first packet in buf.
109 # print buf.__repr__()
110 # print Ether(buf).__repr__()
111 # print len(Ether(buf))
114 ether_type = Ether(buf[0:14]).type
115 except AttributeError:
117 'No EtherType in packet {0}'.format(buf.__repr__()))
119 if ether_type == ETH_P_IP:
120 # 14 is Ethernet fame header size.
121 # 4 bytes is just enough to look for length in ip header.
122 # ip total length contains just the IP packet length so add the Ether
124 pkt_len = Ether(buf[0:14+4]).len + 14
127 elif ether_type == ETH_P_IPV6:
128 if not Ether(buf[0:14+6]).haslayer(IPv6):
130 'Invalid IPv6 packet {0}'.format(buf.__repr__()))
131 # ... to add to the above, 40 bytes is the length of IPV6 header.
132 # The ipv6.len only contains length of the payload and not the header
133 pkt_len = Ether(buf)['IPv6'].plen + 14 + 40
136 elif ether_type == ETH_P_ARP:
137 pkt = Ether(buf[:20])
138 if not pkt.haslayer(ARP):
139 raise RuntimeError('Incomplete ARP packet')
140 # len(eth) + arp(2 hw addr type + 2 proto addr type
141 # + 1b len + 1b len + 2b operation)
144 pkt_len += 2 * pkt.getlayer(ARP).hwlen
145 pkt_len += 2 * pkt.getlayer(ARP).plen
148 elif ether_type == 32821: # RARP (Reverse ARP)
149 pkt = Ether(buf[:20])
150 pkt.type = ETH_P_ARP # Change to ARP so it works with scapy
151 pkt = Ether(str(pkt))
152 if not pkt.haslayer(ARP):
154 raise RuntimeError('Incomplete RARP packet')
156 # len(eth) + arp(2 hw addr type + 2 proto addr type
157 # + 1b len + 1b len + 2b operation)
159 pkt_len += 2 * pkt.getlayer(ARP).hwlen
160 pkt_len += 2 * pkt.getlayer(ARP).plen
164 raise RuntimeError('Unknown protocol {0}'.format(ether_type))
169 if len(buf) < pkt_len:
172 return buf[0:pkt_len]
175 def packet_reader(interface_name, queue):
176 """Sub-process routine that reads packets and puts them to queue.
178 This function is meant to be run in separate subprocess and is in tight
179 loop reading raw packets from interface passed as parameter.
181 :param interace_name: Name of interface to read packets from.
182 :param queue: Queue in which this function will push incoming packets.
183 :type interface_name: string
184 :type queue: multiprocessing.Queue
187 sock = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, ETH_P_ALL)
188 sock.bind((interface_name, ETH_P_ALL))
191 pkt = sock.recv(0x7fff)
195 class RxQueue(PacketVerifier):
196 """Receive queue object.
198 This object creates raw socket, reads packets from it and provides
199 function to access them.
201 :param interface_name: Which interface to bind to.
202 :type interface_name: string
205 def __init__(self, interface_name):
206 PacketVerifier.__init__(self, interface_name)
208 #self._queue = Queue()
209 #self._proc = Process(target=packet_reader, args=(interface_name,
211 #self._proc.daemon = True
215 def recv(self, timeout=3, ignore=None):
216 """Read next received packet.
218 Returns scapy's Ether() object created from next packet in the queue.
219 Queue is being filled in parallel in subprocess. If no packet
220 arrives in given timeout queue.Empty exception will be risen.
222 :param timeout: How many seconds to wait for next packet.
225 :return: Ether() initialized object from packet data.
229 #pkt = self._queue.get(True, timeout=timeout)
230 (rlist, _, _) = select.select([self._sock], [], [], timeout)
231 if self._sock not in rlist:
234 pkt = self._sock.recv(0x7fff)
235 pkt_pad = auto_pad(pkt)
236 print 'Received packet on {0} of len {1}'.format(self._ifname, len(pkt))
240 if ignore is not None:
241 for i, ig_pkt in enumerate(ignore):
242 # Auto pad all packets in ignore list
243 ignore[i] = auto_pad(ig_pkt)
244 for ig_pkt in ignore:
245 if ig_pkt == pkt_pad:
246 # Found the packet in ignore list, get another one
247 # TODO: subtract timeout - time_spent in here
248 ignore.remove(ig_pkt)
249 return self.recv(timeout, ignore)
254 class TxQueue(PacketVerifier):
255 """Transmission queue object.
257 This object is used to send packets over RAW socket on a interface.
259 :param interface_name: Which interface to send packets from.
260 :type interface_name: string
262 def __init__(self, interface_name):
263 PacketVerifier.__init__(self, interface_name)
266 """Send packet out of the bound interface.
268 :param pkt: Packet to send.
269 :type pkt: string or scapy Packet derivative.
271 print 'Sending packet out of {0} of len {1}'.format(self._ifname,
273 Ether(str(pkt)).show2()
276 pkt = auto_pad(str(pkt))
280 class Interface(object):
281 def __init__(self, if_name):
282 self.if_name = if_name
283 self.sent_packets = []
284 self.rxq = RxQueue(if_name)
285 self.txq = TxQueue(if_name)
287 def send_pkt(self, pkt):
288 self.sent_packets.append(pkt)
291 def recv_pkt(self, timeout=3):
292 return self.rxq.recv(timeout, self.sent_packets)
295 #self.rxq._proc.terminate()
299 def create_gratuitous_arp_request(src_mac, src_ip):
300 """Creates scapy representation of gratuitous ARP request"""
301 return (Ether(src=src_mac, dst='ff:ff:ff:ff:ff:ff') /
302 ARP(psrc=src_ip, hwsrc=src_mac, pdst=src_ip))
305 def auto_pad(packet):
306 """Pads zeroes at the end of the packet if the total len < 60 bytes."""
309 padded += ('\0' * (60 - len(padded)))