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      1 ## This file is part of Scapy
      2 ## See http://www.secdev.org/projects/scapy for more informations
      3 ## Copyright (C) Philippe Biondi <phil (at] secdev.org>
      4 ## This program is published under a GPLv2 license
      5 
      6 #############################################################################
      7 ##                                                                         ##
      8 ## hsrp.py --- HSRP  protocol support for Scapy                            ##
      9 ##                                                                         ##
     10 ## Copyright (C) 2010  Mathieu RENARD mathieu.renard(at)gmail.com          ##
     11 ##                                                                         ##
     12 ## This program is free software; you can redistribute it and/or modify it ##
     13 ## under the terms of the GNU General Public License version 2 as          ##
     14 ## published by the Free Software Foundation; version 2.                   ##
     15 ##                                                                         ##
     16 ## This program is distributed in the hope that it will be useful, but     ##
     17 ## WITHOUT ANY WARRANTY; without even the implied warranty of              ##
     18 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU       ##
     19 ## General Public License for more details.                                ##
     20 ##                                                                         ##
     21 #############################################################################
     22 ## HSRP Version 1
     23 ##  Ref. RFC 2281
     24 ## HSRP Version 2
     25 ##  Ref. http://www.smartnetworks.jp/2006/02/hsrp_8_hsrp_version_2.html
     26 ##
     27 ## $Log: hsrp.py,v $
     28 ## Revision 0.2  2011/05/01 15:23:34  mrenard
     29 ##   Cleanup code
     30 
     31 """
     32 HSRP (Hot Standby Router Protocol): proprietary redundancy protocol for Cisco routers.
     33 """
     34 
     35 from scapy.fields import *
     36 from scapy.packet import *
     37 from scapy.layers.inet import DestIPField, UDP
     38 from scapy.layers.inet6 import DestIP6Field
     39 
     40 
     41 class HSRP(Packet):
     42     name = "HSRP"
     43     fields_desc = [
     44         ByteField("version", 0),
     45         ByteEnumField("opcode", 0, {0: "Hello", 1: "Coup", 2: "Resign", 3: "Advertise"}),
     46         ByteEnumField("state", 16, {0: "Initial", 1: "Learn", 2: "Listen", 4: "Speak", 8: "Standby", 16: "Active"}),
     47         ByteField("hellotime", 3),
     48         ByteField("holdtime", 10),
     49         ByteField("priority", 120),
     50         ByteField("group", 1),
     51         ByteField("reserved", 0),
     52         StrFixedLenField("auth", b"cisco" + b"\00" * 3, 8),
     53         IPField("virtualIP", "192.168.1.1")]
     54 
     55     def guess_payload_class(self, payload):
     56         if self.underlayer.len > 28:
     57             return HSRPmd5
     58         else:
     59             return Packet.guess_payload_class(self, payload)
     60 
     61 
     62 class HSRPmd5(Packet):
     63     name = "HSRP MD5 Authentication"
     64     fields_desc = [
     65         ByteEnumField("type", 4, {4: "MD5 authentication"}),
     66         ByteField("len", None),
     67         ByteEnumField("algo", 0, {1: "MD5"}),
     68         ByteField("padding", 0x00),
     69         XShortField("flags", 0x00),
     70         SourceIPField("sourceip", None),
     71         XIntField("keyid", 0x00),
     72         StrFixedLenField("authdigest", b"\00" * 16, 16)]
     73 
     74     def post_build(self, p, pay):
     75         if self.len is None and pay:
     76             l = len(pay)
     77             p = p[:1] + hex(l)[30:] + p[30:]
     78         return p
     79 
     80 bind_layers(UDP, HSRP, dport=1985, sport=1985)
     81 bind_layers(UDP, HSRP, dport=2029, sport=2029)
     82 DestIPField.bind_addr(UDP, "224.0.0.2", dport=1985)
     83 DestIP6Field.bind_addr(UDP, "ff02::66", dport=2029)
     84