diff --git a/scapy/layers/hsrp.py b/scapy/layers/hsrp.py
index acf800c26aa2c0c9092a674d5280487db06e6c0c..7193b97e6a9c3cf0d3458e2f594875b129072012 100644
--- a/scapy/layers/hsrp.py
+++ b/scapy/layers/hsrp.py
@@ -3,6 +3,31 @@
## Copyright (C) Philippe Biondi <phil@secdev.org>
## This program is published under a GPLv2 license
+#############################################################################
+## ##
+## hsrp.py --- HSRP protocol support for Scapy ##
+## ##
+## Copyright (C) 2010 Mathieu RENARD mathieu.renard(at)gmail.com ##
+## ##
+## This program is free software; you can redistribute it and/or modify it ##
+## under the terms of the GNU General Public License version 2 as ##
+## published by the Free Software Foundation; version 2. ##
+## ##
+## This program 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. ##
+## ##
+#############################################################################
+## HSRP Version 1
+## Ref. RFC 2281
+## HSRP Version 2
+## Ref. http://www.smartnetworks.jp/2006/02/hsrp_8_hsrp_version_2.html
+##
+## $Log: hsrp.py,v $
+## Revision 0.2 2011/05/01 15:23:34 mrenard
+## Cleanup code
+
"""
HSRP (Hot Standby Router Protocol): proprietary redundancy protocol for Cisco routers.
"""
@@ -11,22 +36,44 @@ from scapy.fields import *
from scapy.packet import *
from scapy.layers.inet import UDP
+
class HSRP(Packet):
name = "HSRP"
fields_desc = [
ByteField("version", 0),
- ByteEnumField("opcode", 0, { 0:"Hello", 1:"Coup", 2:"Resign", 3:"Advertise"}),
- ByteEnumField("state", 16, { 0:"Initial", 1:"Learn", 2:"Listen", 4:"Speak", 8:"Standby", 16:"Active"}),
+ ByteEnumField("opcode", 0, {0: "Hello", 1: "Coup", 2: "Resign", 3: "Advertise"}),
+ ByteEnumField("state", 16, {0: "Initial", 1: "Learn", 2: "Listen", 4: "Speak", 8: "Standby", 16: "Active"}),
ByteField("hellotime", 3),
ByteField("holdtime", 10),
ByteField("priority", 120),
ByteField("group", 1),
ByteField("reserved", 0),
- StrFixedLenField("auth","cisco",8),
- IPField("virtualIP","192.168.1.1") ]
-
+ StrFixedLenField("auth", "cisco" + "\00" * 3, 8),
+ IPField("virtualIP", "192.168.1.1")]
+
+ def guess_payload_class(self, payload):
+ if self.underlayer.len > 28:
+ return HSRPmd5
+ else:
+ return Packet.guess_payload_class(self, payload)
+
+
+class HSRPmd5(Packet):
+ name = "HSRP MD5 Authentication"
+ fields_desc = [
+ ByteEnumField("type", 4, {4: "MD5 authentication"}),
+ ByteField("len", None),
+ ByteEnumField("algo", 0, {1: "MD5"}),
+ ByteField("padding", 0x00),
+ XShortField("flags", 0x00),
+ IPField("sourceip", None),
+ XIntField("keyid", 0x00),
+ StrFixedLenField("authdigest", "\00" * 16, 16)]
+ def post_build(self, p, pay):
+ if self.len is None and pay:
+ l = len(pay)
+ p = p[:1] + hex(l)[30:] + p[30:]
+ return p
-
-
-bind_layers( UDP, HSRP, dport=1985, sport=1985)
+bind_layers(UDP, HSRP, dport=1985, sport=1985)