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Added VTP as contrib (ticket #179)
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‎scapy/contrib/vtp.py‎

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#!/usr/bin/env python
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# scapy.contrib.description = VLAN Trunking Protocol (VTP)
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# scapy.contrib.status = loads
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"""
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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" sais the TLV length is invalid,
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when I change the values
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'\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
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"""
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from scapy.all import *
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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 Padding
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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), # FIXME: compute length
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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", length_from=lambda pkt:4 * ((pkt.vlannamelen + 3) / 4)),
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ConditionalField(PacketListField("tlvlist", [], VTPVlanInfoTlv,
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length_from=lambda pkt:pkt.len - 12 - (4 * ((pkt.vlannamelen + 3) / 4))),
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lambda pkt:pkt.type not in [1, 2])
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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 == None:
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l = vlannamelen + 12
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p = chr(l & 0xff) + p[1:]
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# Pad vlan name with zeros if vlannamelen > len(vlanname)
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l = vlannamelen - len(self.vlanname)
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if l != 0:
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p += "\x00" * l
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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 Padding
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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])
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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", "\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 == None:
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domnamelen = len(self.domname.strip("\x00"))
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p = p[:3] + chr(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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interact(mydict=globals(), mybanner="VTP")

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