81 lines
2.8 KiB
Python
Executable file
81 lines
2.8 KiB
Python
Executable file
# This file is part of Scapy
|
|
# Scapy is free software: you can redistribute it and/or modify
|
|
# it under the terms of the GNU General Public License as published by
|
|
# the Free Software Foundation, either version 2 of the License, or
|
|
# any later version.
|
|
#
|
|
# Scapy is distributed in the hope that it will be useful,
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
# GNU General Public License for more details.
|
|
#
|
|
# You should have received a copy of the GNU General Public License
|
|
# along with Scapy. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
# scapy.contrib.description = Common Address Redundancy Protocol (CARP)
|
|
# scapy.contrib.status = loads
|
|
|
|
import struct
|
|
import hmac
|
|
import hashlib
|
|
|
|
from scapy.packet import Packet, split_layers, bind_layers
|
|
from scapy.layers.inet import IP
|
|
from scapy.fields import BitField, ByteField, XShortField, XIntField
|
|
from scapy.layers.vrrp import IPPROTO_VRRP, VRRP, VRRPv3
|
|
from scapy.utils import checksum, inet_aton
|
|
from scapy.error import warning
|
|
|
|
|
|
class CARP(Packet):
|
|
name = "CARP"
|
|
fields_desc = [BitField("version", 4, 4),
|
|
BitField("type", 4, 4),
|
|
ByteField("vhid", 1),
|
|
ByteField("advskew", 0),
|
|
ByteField("authlen", 0),
|
|
ByteField("demotion", 0),
|
|
ByteField("advbase", 0),
|
|
XShortField("chksum", None),
|
|
XIntField("counter1", 0),
|
|
XIntField("counter2", 0),
|
|
XIntField("hmac1", 0),
|
|
XIntField("hmac2", 0),
|
|
XIntField("hmac3", 0),
|
|
XIntField("hmac4", 0),
|
|
XIntField("hmac5", 0)
|
|
]
|
|
|
|
def post_build(self, pkt, pay):
|
|
if self.chksum is None:
|
|
pkt = pkt[:6] + struct.pack("!H", checksum(pkt)) + pkt[8:]
|
|
|
|
return pkt
|
|
|
|
def build_hmac_sha1(self, pw=b'\x00' * 20, ip4l=[], ip6l=[]):
|
|
h = hmac.new(pw, digestmod=hashlib.sha1)
|
|
# XXX: this is a dirty hack. it needs to pack version and type into a single 8bit field # noqa: E501
|
|
h.update(b'\x21')
|
|
# XXX: mac addy if different from special link layer. comes before vhid
|
|
h.update(struct.pack('!B', self.vhid))
|
|
|
|
sl = []
|
|
for i in ip4l:
|
|
# sort ips from smallest to largest
|
|
sl.append(inet_aton(i))
|
|
sl.sort()
|
|
|
|
for i in sl:
|
|
h.update(i)
|
|
|
|
# XXX: do ip6l sorting
|
|
|
|
return h.digest()
|
|
|
|
|
|
warning("CARP overwrites VRRP !")
|
|
# This cancel the bindings done in vrrp.py
|
|
split_layers(IP, VRRP, proto=IPPROTO_VRRP)
|
|
split_layers(IP, VRRPv3, proto=IPPROTO_VRRP)
|
|
# CARP bindings
|
|
bind_layers(IP, CARP, proto=112, dst='224.0.0.18')
|