• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1# SPDX-License-Identifier: GPL-2.0-only
2# This file is part of Scapy
3# See https://scapy.net/ for more information
4# Copyright (C)  Mathieu RENARD <mathieu.renard(at)gmail.com>
5
6"""
7HSRP (Hot Standby Router Protocol)
8A proprietary redundancy protocol for Cisco routers.
9
10- HSRP Version 1: RFC 2281
11- HSRP Version 2:
12    http://www.smartnetworks.jp/2006/02/hsrp_8_hsrp_version_2.html
13"""
14
15from scapy.config import conf
16from scapy.fields import ByteEnumField, ByteField, IPField, SourceIPField, \
17    StrFixedLenField, XIntField, XShortField
18from scapy.packet import Packet, bind_layers, bind_bottom_up
19from scapy.layers.inet import DestIPField, UDP
20
21
22class HSRP(Packet):
23    name = "HSRP"
24    fields_desc = [
25        ByteField("version", 0),
26        ByteEnumField("opcode", 0, {0: "Hello", 1: "Coup", 2: "Resign", 3: "Advertise"}),  # noqa: E501
27        ByteEnumField("state", 16, {0: "Initial", 1: "Learn", 2: "Listen", 4: "Speak", 8: "Standby", 16: "Active"}),  # noqa: E501
28        ByteField("hellotime", 3),
29        ByteField("holdtime", 10),
30        ByteField("priority", 120),
31        ByteField("group", 1),
32        ByteField("reserved", 0),
33        StrFixedLenField("auth", b"cisco" + b"\00" * 3, 8),
34        IPField("virtualIP", "192.168.1.1")]
35
36    def guess_payload_class(self, payload):
37        if self.underlayer.len > 28:
38            return HSRPmd5
39        else:
40            return Packet.guess_payload_class(self, payload)
41
42
43class HSRPmd5(Packet):
44    name = "HSRP MD5 Authentication"
45    fields_desc = [
46        ByteEnumField("type", 4, {4: "MD5 authentication"}),
47        ByteField("len", None),
48        ByteEnumField("algo", 0, {1: "MD5"}),
49        ByteField("padding", 0x00),
50        XShortField("flags", 0x00),
51        SourceIPField("sourceip"),
52        XIntField("keyid", 0x00),
53        StrFixedLenField("authdigest", b"\00" * 16, 16)]
54
55    def post_build(self, p, pay):
56        if self.len is None and pay:
57            tmp_len = len(pay)
58            p = p[:1] + hex(tmp_len)[30:] + p[30:]
59        return p
60
61
62bind_bottom_up(UDP, HSRP, dport=1985)
63bind_bottom_up(UDP, HSRP, sport=1985)
64bind_bottom_up(UDP, HSRP, dport=2029)
65bind_bottom_up(UDP, HSRP, sport=2029)
66bind_layers(UDP, HSRP, dport=1985, sport=1985)
67bind_layers(UDP, HSRP, dport=2029, sport=2029)
68DestIPField.bind_addr(UDP, "224.0.0.2", dport=1985)
69if conf.ipv6_enabled:
70    from scapy.layers.inet6 import DestIP6Field
71    DestIP6Field.bind_addr(UDP, "ff02::66", dport=2029)
72