86890704fd
todo: add documentation & wireshark dissector
204 lines
6.6 KiB
Python
Executable file
204 lines
6.6 KiB
Python
Executable file
# This file is part of Scapy
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# Scapy is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 2 of the License, or
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# any later version.
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#
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# Scapy is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with Scapy. If not, see <http://www.gnu.org/licenses/>.
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# scapy.contrib.description = VLAN Trunking Protocol (VTP)
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# scapy.contrib.status = loads
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r"""
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VTP Scapy Extension
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~~~~~~~~~~~~~~~~~~~~~
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:version: 2009-02-15
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:copyright: 2009 by Jochen Bartl
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:e-mail: lobo@c3a.de / jochen.bartl@gmail.com
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:license: GPL v2
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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:TODO:
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- Join messages
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- RE MD5 hash calculation
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- Have a closer look at 8 byte padding in summary adv:
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"debug sw-vlan vtp packets" says the TLV length is invalid,
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when I change the values:
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``b'\x00\x00\x00\x01\x06\x01\x00\x02'``
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* \x00\x00 ?
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* \x00\x01 tlvtype?
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* \x06 length?
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* \x00\x02 value?
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- h2i function for VTPTimeStampField
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:References:
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- | Understanding VLAN Trunk Protocol (VTP)
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| http://www.cisco.com/en/US/tech/tk389/tk689/technologies_tech_note09186a0080094c52.shtml # noqa: E501
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"""
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from scapy.packet import Packet, bind_layers
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from scapy.fields import ByteEnumField, ByteField, ConditionalField, \
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FieldLenField, IPField, PacketListField, ShortField, SignedIntField, \
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StrFixedLenField, StrLenField, XIntField
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from scapy.layers.l2 import SNAP
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from scapy.compat import chb
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from scapy.config import conf
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_VTP_VLAN_TYPE = {
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1: 'Ethernet',
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2: 'FDDI',
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3: 'TrCRF',
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4: 'FDDI-net',
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5: 'TrBRF'
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}
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_VTP_VLANINFO_TLV_TYPE = {
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0x01: 'Source-Routing Ring Number',
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0x02: 'Source-Routing Bridge Number',
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0x03: 'Spanning-Tree Protocol Type',
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0x04: 'Parent VLAN',
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0x05: 'Translationally Bridged VLANs',
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0x06: 'Pruning',
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0x07: 'Bridge Type',
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0x08: 'Max ARE Hop Count',
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0x09: 'Max STE Hop Count',
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0x0A: 'Backup CRF Mode'
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}
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class VTPVlanInfoTlv(Packet):
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name = "VTP VLAN Info TLV"
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fields_desc = [
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ByteEnumField("type", 0, _VTP_VLANINFO_TLV_TYPE),
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ByteField("length", 0),
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StrLenField("value", None, length_from=lambda pkt: pkt.length + 1)
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]
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def guess_payload_class(self, p):
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return conf.padding_layer
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class VTPVlanInfo(Packet):
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name = "VTP VLAN Info"
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fields_desc = [
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ByteField("len", None),
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ByteEnumField("status", 0, {0: "active", 1: "suspended"}),
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ByteEnumField("type", 1, _VTP_VLAN_TYPE),
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FieldLenField("vlannamelen", None, "vlanname", "B"),
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ShortField("vlanid", 1),
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ShortField("mtu", 1500),
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XIntField("dot10index", None),
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StrLenField("vlanname", "default",
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length_from=lambda pkt: 4 * ((pkt.vlannamelen + 3) // 4)),
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ConditionalField(
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PacketListField(
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"tlvlist", [], VTPVlanInfoTlv,
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length_from=lambda pkt: pkt.len - 12 - (4 * ((pkt.vlannamelen + 3) // 4)) # noqa: E501
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),
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lambda pkt:pkt.type not in [1, 2]
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)
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]
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def post_build(self, p, pay):
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vlannamelen = 4 * ((len(self.vlanname) + 3) // 4)
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if self.len is None:
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tmp_len = vlannamelen + 12
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p = chb(tmp_len & 0xff) + p[1:]
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# Pad vlan name with zeros if vlannamelen > len(vlanname)
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tmp_len = vlannamelen - len(self.vlanname)
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if tmp_len != 0:
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p += b"\x00" * tmp_len
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p += pay
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return p
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def guess_payload_class(self, p):
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return conf.padding_layer
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_VTP_Types = {
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1: 'Summary Advertisement',
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2: 'Subset Advertisements',
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3: 'Advertisement Request',
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4: 'Join'
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}
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class VTPTimeStampField(StrFixedLenField):
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def __init__(self, name, default):
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StrFixedLenField.__init__(self, name, default, 12)
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def i2repr(self, pkt, x):
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return "%s-%s-%s %s:%s:%s" % (x[:2], x[2:4], x[4:6], x[6:8], x[8:10], x[10:12]) # noqa: E501
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class VTP(Packet):
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name = "VTP"
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fields_desc = [
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ByteField("ver", 2),
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ByteEnumField("code", 1, _VTP_Types),
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ConditionalField(ByteField("followers", 1),
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lambda pkt:pkt.code == 1),
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ConditionalField(ByteField("seq", 1),
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lambda pkt:pkt.code == 2),
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ConditionalField(ByteField("reserved", 0),
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lambda pkt:pkt.code == 3),
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ByteField("domnamelen", None),
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StrFixedLenField("domname", "manbearpig", 32),
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ConditionalField(SignedIntField("rev", 0),
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lambda pkt:pkt.code == 1 or
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pkt.code == 2),
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# updater identity
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ConditionalField(IPField("uid", "192.168.0.1"),
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lambda pkt:pkt.code == 1),
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ConditionalField(VTPTimeStampField("timestamp", '930301000000'),
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lambda pkt:pkt.code == 1),
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ConditionalField(StrFixedLenField("md5", b"\x00" * 16, 16),
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lambda pkt:pkt.code == 1),
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ConditionalField(
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PacketListField("vlaninfo", [], VTPVlanInfo),
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lambda pkt: pkt.code == 2),
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ConditionalField(ShortField("startvalue", 0),
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lambda pkt:pkt.code == 3)
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]
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def post_build(self, p, pay):
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if self.domnamelen is None:
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domnamelen = len(self.domname.strip(b"\x00"))
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p = p[:3] + chb(domnamelen & 0xff) + p[4:]
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p += pay
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return p
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bind_layers(SNAP, VTP, code=0x2003)
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if __name__ == '__main__':
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from scapy.main import interact
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interact(mydict=globals(), mybanner="VTP")
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