# This file is part of Scapy
# See http://www.secdev.org/projects/scapy for more information
# 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.  # noqa: E501
"""

from scapy.fields import ByteEnumField, ByteField, IPField, SourceIPField, \
    StrFixedLenField, XIntField, XShortField
from scapy.packet import Packet, bind_layers, bind_bottom_up
from scapy.layers.inet import DestIPField, UDP
from scapy.layers.inet6 import DestIP6Field


class HSRP(Packet):
    name = "HSRP"
    fields_desc = [
        ByteField("version", 0),
        ByteEnumField("opcode", 0, {0: "Hello", 1: "Coup", 2: "Resign", 3: "Advertise"}),  # noqa: E501
        ByteEnumField("state", 16, {0: "Initial", 1: "Learn", 2: "Listen", 4: "Speak", 8: "Standby", 16: "Active"}),  # noqa: E501
        ByteField("hellotime", 3),
        ByteField("holdtime", 10),
        ByteField("priority", 120),
        ByteField("group", 1),
        ByteField("reserved", 0),
        StrFixedLenField("auth", b"cisco" + b"\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),
        SourceIPField("sourceip", None),
        XIntField("keyid", 0x00),
        StrFixedLenField("authdigest", b"\00" * 16, 16)]

    def post_build(self, p, pay):
        if self.len is None and pay:
            tmp_len = len(pay)
            p = p[:1] + hex(tmp_len)[30:] + p[30:]
        return p


bind_bottom_up(UDP, HSRP, dport=1985)
bind_bottom_up(UDP, HSRP, sport=1985)
bind_bottom_up(UDP, HSRP, dport=2029)
bind_bottom_up(UDP, HSRP, sport=2029)
bind_layers(UDP, HSRP, dport=1985, sport=1985)
bind_layers(UDP, HSRP, dport=2029, sport=2029)
DestIPField.bind_addr(UDP, "224.0.0.2", dport=1985)
DestIP6Field.bind_addr(UDP, "ff02::66", dport=2029)