chksum = 0xa607
src = 11.11.11.11
dst = 11.11.11.10
- \options \
+ options
###[ ICMP ]###
type = echo-reply
code = 0
"""
+import os
import socket
import select
-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.all import Ether, ARP
from scapy.layers.inet6 import IPv6
__all__ = ['RxQueue', 'TxQueue', 'Interface', 'create_gratuitous_arp_request',
- 'auto_pad']
+ 'auto_pad', 'checksum_equal']
+
+# TODO: http://stackoverflow.com/questions/320232/
+# ensuring-subprocesses-are-dead-on-exiting-python-program
-# 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."""
self._sock = socket.socket(socket.AF_PACKET, socket.SOCK_RAW,
ETH_P_ALL)
self._sock.bind((interface_name, ETH_P_ALL))
+ self._ifname = interface_name
def extract_one_packet(buf):
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
+ :param buf: String representation of incoming packet buffer.
+ :type buf: str
+ :returns: String representation of first packet in buf.
+ :rtype: str
"""
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:
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 interface_name: Name of interface to read packets from.
:param queue: Queue in which this function will push incoming packets.
- :type interface_name: string
+ :type interface_name: str
:type queue: multiprocessing.Queue
- :return: None
+ :returns: None
"""
sock = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, ETH_P_ALL)
sock.bind((interface_name, ETH_P_ALL))
function to access them.
:param interface_name: Which interface to bind to.
- :type interface_name: string
+ :type interface_name: str
"""
-
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):
+ def recv(self, timeout=3, ignore=None, verbose=True):
"""Read next received packet.
Returns scapy's Ether() object created from next packet in the queue.
arrives in given timeout queue.Empty exception will be risen.
:param timeout: How many seconds to wait for next packet.
+ :param ignore: List of packets that should be ignored.
+ :param verbose: Used to suppress detailed logging of received packets.
:type timeout: int
+ :type ignore: list
+ :type verbose: bool
- :return: Ether() initialized object from packet data.
+ :returns: Ether() initialized object from packet data.
:rtype: scapy.Ether
"""
-
- #pkt = self._queue.get(True, timeout=timeout)
(rlist, _, _) = select.select([self._sock], [], [], timeout)
if self._sock not in rlist:
return None
pkt = self._sock.recv(0x7fff)
+ pkt_pad = auto_pad(pkt)
+ print'Received packet on {0} of len {1}'.format(self._ifname, len(pkt))
+ if verbose:
+ Ether(pkt).show2()
+ print
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:
+ if ig_pkt == pkt_pad:
# 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 self.recv(timeout, ignore, verbose)
return Ether(pkt)
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
+ :type interface_name: str
"""
def __init__(self, interface_name):
PacketVerifier.__init__(self, interface_name)
- def send(self, pkt):
+ def send(self, pkt, verbose=True):
"""Send packet out of the bound interface.
:param pkt: Packet to send.
+ :param verbose: Used to supress detailed logging of sent packets.
:type pkt: string or scapy Packet derivative.
+ :type verbose: bool
"""
+ print 'Sending packet out of {0} of len {1}'.format(self._ifname,
+ len(pkt))
+ if verbose:
+ Ether(str(pkt)).show2()
+ print
+
pkt = auto_pad(str(pkt))
self._sock.send(pkt)
class Interface(object):
+ """Class for network interfaces. Contains methods for sending and receiving
+ packets."""
def __init__(self, if_name):
+ """Initialize the interface class.
+
+ :param if_name: Name of the interface.
+ :type if_name: str
+ """
self.if_name = if_name
self.sent_packets = []
self.rxq = RxQueue(if_name)
self.txq = TxQueue(if_name)
def send_pkt(self, pkt):
+ """Send the provided packet out the interface."""
self.sent_packets.append(pkt)
self.txq.send(pkt)
def recv_pkt(self, timeout=3):
- return self.rxq.recv(timeout, self.sent_packets)
+ """Read one packet from the interface's receive queue.
- def close(self):
- #self.rxq._proc.terminate()
- pass
+ :param timeout: Timeout value in seconds.
+ :type timeout: int
+ :returns: Ether() initialized object from packet data.
+ :rtype: scapy.Ether
+ """
+ return self.rxq.recv(timeout, self.sent_packets)
def create_gratuitous_arp_request(src_mac, src_ip):
- """Creates scapy representation of gratuitous ARP request"""
+ """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))
padded += ('\0' * (60 - len(padded)))
return padded
+
+def checksum_equal(chksum1, chksum2):
+ """Compares two checksums in one's complement notation.
+
+ Checksums to be compared are calculated as 16 bit one's complement of the
+ one's complement sum of 16 bit words of some buffer.
+ In one's complement notation 0x0000 (positive zero) and 0xFFFF
+ (negative zero) are equivalent.
+
+ :param chksum1: First checksum.
+ :param chksum2: Second checksum.
+ :type chksum1: uint16
+ :type chksum2: uint16
+
+ :returns: True if checksums are equivalent, False otherwise.
+ :rtype: boolean
+ """
+ if chksum1 == 0xFFFF:
+ chksum1 = 0
+ if chksum2 == 0xFFFF:
+ chksum2 = 0
+ return chksum1 == chksum2