Scapy | the broadcast

2018-11-072018-11-07

Python: Combine NetIfaces, Scapy and IPAddress to find local connected network

You got the task to generate a list of IP-Networks connected to LAN „VirtualBox Host-Only Network“. There might be more than one IP-Network.

Use Scapy to crawl through all Interfaces and get the human-readable interface name [only required for windows users]. Use NetIfaces to get a list of IP-Addresses connected to this interface. Use IPAddress to calculate the IP-Network(s) directly connected.

! multiple IPs per Interface supporte
!
from netifaces import AF_INET, AF_INET6, AF_LINK
import netifaces

from scapy.all import *

import ipaddress


if_name = "VirtualBox Host-Only Network"
if_id = ""
if_inet = []

for i in ifaces.data.keys():
  iface = ifaces.data[i]
  wname = iface.data['netid']
  if wname == if_name:
    if_id = i
    addresses = netifaces.ifaddresses(i)
    if AF_INET in addresses:
      for addr in netifaces.ifaddresses(i)[AF_INET]:
        print(addr)
        ipaddr = ipaddress.ip_interface(addr["addr"]+"/"+addr["netmask"])
        ipnetwork = ipaddr.network
        print(ipaddr,ipnetwork)
        if_inet.append(ipnetwork)

print("NAME: {0}\nIP: {1}\nID: {2}".format(if_name,if_inet,if_id))

In my case, only one subnet is directly connected:

192.168.56.0/24

...
{'addr': '192.168.56.1', 'netmask': '255.255.255.0', 'broadcast': '192.168.56.255'}
192.168.56.1/24 192.168.56.0/24
>>> print("NAME: {0}\nIP: {1}\nID: {2}".format(if_name,if_inet,if_id))
NAME: VirtualBox Host-Only Network
IP: [IPv4Network('192.168.56.0/24')]
ID: {D30DEC05-D495-4DA1-81F1-42B07885B0EB}
>>>

2018-11-062018-11-05

Python netifaces and scapy: Getting meaningful Interface-names and full IP-Adresses-/Netmask-Information

Using Windows:

scapy reads:
- meaningful interface-names
- ip-address
- but no netmask
netifaces reads:
- full Ethernet/IP/IPv6-Information
- but no meaningful interface-names

Mixing both, provides everything needed.

Netifaces only

from netifaces import AF_INET, AF_INET6, AF_LINK
import netifaces

for i in netifaces.interfaces():
   niif=netifaces.ifaddresses(i)
   print("i",i)
   for k,v in niif.items():
     print("Key",k)
     if k==AF_LINK:
       print("LINK:",v)
     if k==AF_INET:
       print("IPv4",v)
     if k==AF_INET6:
       print("IPv6",v)
   print()

>>> for i in netifaces.interfaces():
...    niif=netifaces.ifaddresses(i)
...    print("i",i)
...    for k,v in niif.items():
...      print("Key",k)
...      if k==AF_LINK:
...        print("LINK:",v)
...      if k==AF_INET:
...        print("IPv4",v)
...      if k==AF_INET6:
...        print("IPv6",v)
...    print()
...
i {07E9D8A4-E167-4FFF-B851-61A20C49AE6E}
Key -1000
LINK: [{'addr': '00:00:81:00:de:11'}]
Key 23
IPv6 [{'addr': 'fe80::8400:abb0:2a62:a173%4', 'netmask': 'ffff:ffff:ffff:ffff::/64', 'broadcast': 'fe80::ffff:ffff:ffff:ffff%4'}]

i {D30DEC05-D495-4DA1-81F1-42B07885B0EB}
Key -1000
LINK: [{'addr': '0a:00:27:00:00:14'}]
Key 23
IPv6 [{'addr': 'fe80::1e0:4a4:8afc:90f7%20', 'netmask': 'ffff:ffff:ffff:ffff::/64', 'broadcast': 'fe80::ffff:ffff:ffff:ffff%20'}]
Key 2
IPv4 [{'addr': '192.168.56.1', 'netmask': '255.255.255.0', 'broadcast': '192.168.56.255'}]

i {402C453F-4B74-4883-9257-BD31FAB7AB57}
Key -1000
LINK: [{'addr': '74:70:fd:bd:10:38'}]
Key 23
IPv6 [{'addr': 'fe80::2599:368f:e80d:94b6%8', 'netmask': 'ffff:ffff:ffff:ffff::/64', 'broadcast': 'fe80::ffff:ffff:ffff:ffff%8'}]

i {2120C2CA-E7D4-45DF-8090-A8D7F48EFF42}
Key -1000
LINK: [{'addr': '76:70:fd:bd:10:37'}]
Key 23
IPv6 [{'addr': 'fe80::34d6:9683:4af5:afad%6', 'netmask': 'ffff:ffff:ffff:ffff::/64', 'broadcast': 'fe80::ffff:ffff:ffff:ffff%6'}]

i {F931F123-70A4-4CFB-BD9C-C0A509080286}
Key -1000
LINK: [{'addr': '74:70:fd:bd:10:37'}]
Key 23
IPv6 [{'addr': 'fe80::1926:3c29:1b34:e1f6%22', 'netmask': 'ffff:ffff:ffff:ffff::/64', 'broadcast': 'fe80::ffff:ffff:ffff:ffff%22'}]
Key 2
IPv4 [{'addr': '192.168.1.163', 'netmask': '255.255.255.0', 'broadcast': '192.168.1.255'}]

i {693A5869-6A31-11E8-85D1-806E6F6E6963}
Key -1000
LINK: [{'addr': ''}]
Key 23
IPv6 [{'addr': '::1', 'netmask': 'ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff/128', 'broadcast': '::1'}]
Key 2
IPv4 [{'addr': '127.0.0.1', 'netmask': '255.0.0.0', 'broadcast': '127.255.255.255'}]

Adding Scapy to get meaningful interface names

from scapy.all import *

for i in ifaces.data.keys():
  print(i)
  iface = ifaces.data[i]
  wname = iface.data['netid']
  addresses = netifaces.ifaddresses(i)
  af_inet = [{"addr": "0.0.0.0", "netmask": "0.0.0.0", "broadcast": "0.0.0.0"}]
  if AF_INET in addresses:
    af_inet = netifaces.ifaddresses(i)[AF_INET]
  print(wname,af_inet)

>>> for i in ifaces.data.keys():
...   print(i)
...   iface = ifaces.data[i]
...   wname = iface.data['netid']
...   addresses = netifaces.ifaddresses(i)
...   af_inet = [{"addr": "0.0.0.0", "netmask": "0.0.0.0", "broadcast": "0.0.0.0"}]
...   if AF_INET in addresses:
...     af_inet = netifaces.ifaddresses(i)[AF_INET]
...   print(wname,af_inet)
...
{F931F123-70A4-4CFB-BD9C-C0A509080286}
Wi-Fi [{'addr': '192.168.1.163', 'netmask': '255.255.255.0', 'broadcast': '192.168.1.255'}]
{D30DEC05-D495-4DA1-81F1-42B07885B0EB}
VirtualBox Host-Only Network [{'addr': '192.168.56.1', 'netmask': '255.255.255.0', 'broadcast': '192.168.56.255'}]
{07E9D8A4-E167-4FFF-B851-61A20C49AE6E}
ETH_DELL [{'addr': '0.0.0.0', 'netmask': '0.0.0.0', 'broadcast': '0.0.0.0'}]

2018-11-022018-11-14

Python Scapy: Wait for CDP-Neighbor

After provisioning a new Cisco CSR1000V-Router this script

waits until the router is fully deployed
got it’s Management-IP-Address assigned via DHCP.

and returns this Management IP-Address.

Prepare

First, install „netaddr“-package.

needed to check, if the management-IP of the CDP-Neighbor is in the correct IP-Subnet

C:\RH>pip install netaddr
Collecting netaddr
  Downloading https://files.pythonhosted.org/packages/ba/97/ce14451a9fd7bdb5a397abf99b24a1a6bb7a1a440b019bebd2e9a0dbec74/netaddr-0.7.19-py2.py3-none-any.whl (1.6MB)
    100% |████████████████████████████████| 1.6MB 4.0MB/s
Installing collected packages: netaddr
Successfully installed netaddr-0.7.19

the „wait-for-CDP“-Script

Obviously far to much hard-coded stuff, just as an example 😉 waiting for a CDP-Neighbor to appear with the following properties:

hostname „CSR-A“
an IP-Address within the network „192.168.56.0 /24“

at the interface

VirtualBox Host-Only-Network

#! /usr/bin/env python

from scapy.all import *
load_contrib("cdp")

from netaddr import IPNetwork, IPAddress

# run it for max. 99 Packets
ip = "0.0.0.0"
wait_for_hostname = "CSR-A"
wait_for_host_in_network = "192.168.56.0/24"

interface="VirtualBox Host-Only Ethernet Adapter"
capturefilter="ether dst 01:00:0c:cc:cc:cc"

while not(IPAddress(ip) in IPNetwork(wait_for_host_in_network)):
  p=sniff(iface=interface, count=1, filter=capturefilter)
  pkt=p[0]
  #print("Packet received",pkt.show())

  #is this a CDP-Packet containing a hostname?
  if (CDPMsgDeviceID in pkt):
    #is this the CDP-Neighbor we're looking for?
    device=pkt["CDPMsgDeviceID"].val.decode()
    hostname=device.split(".")[0]
    #print("Hostname:",hostname)

    if (hostname == wait_for_hostname):
      #is this a CDP-Packet containing a management-IP-Address?
      if (CDPAddrRecordIPv4 in pkt):
        ip=pkt["CDPAddrRecordIPv4"].addr
        #print("IP-Address found:",ip)

#return the IP-Address to the calling application or the CLI
print(ip)

Provision a new CSR1000V Router named „CSR-A“

C:\RH>CSR1000v-Virtual-Box.cmd
Enter CSR1000v Hostname:CSR-A
Virtual machine 'CSR-A' is created and registered.
UUID: 8a9c969e-3895-4a7c-9cbc-5f5551bf1b7b
Settings file: 'c:\RH\LAB\VM\CSR-A\CSR-A.vbox'
Creating ISO image at c:\RH\LAB\VM\CSR-A\config.iso, 1 Files, Size: 8,00 KB
100%
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%
Medium created. UUID: 55ea8df5-7e3c-4485-8e08-9302cb61a09d
Waiting for VM "CSR-A" to power on...
VM "CSR-A" has been successfully started.

Run the „wait-for-CDP-Neighbor“-Script

In a second CMD-Box, and… Be patient, of course.

C:\RH>python wait-for-cdpneighbor.py
192.168.56.101

Or store the returned IP-Address in an Shell-Variable „ROUTER-IP“/li>

C:\RH>for /f %I in ('python wait-for-cdpneighbor.py 2^> nul') do @(set ROUTER-IP=%I)

and pass it to putty – using public-key authentication

The Public-Key for user „labuser“ is part of my baseline-config used to provision the virtual-router.

C:\RH>putty -ssh -i C:\RH\work\putty-rsa-key\labuser.ppk labuser@%ROUTER-IP%

Works, this is a nice preparation for an automated virtual ansible-lab, too!

2018-11-012018-10-30

Python Scapy: CDP-Monitor

Watch and decode Cisco Discovery Protocol Packetes.

CDP Monitor-Script

Inspired by the Scapy ARP-Monitor i created an CDP-Monitor displaying hostname and an optional Management-IP-Address.

#! /usr/bin/env python
from scapy.all import *
load_contrib("cdp")

def cdp_monitor_callback(pkt):
  ip = "0.0.0.0"
  if (CDPMsgDeviceID in pkt):
    device=pkt["CDPMsgDeviceID"].val.decode()
    hostname=device.split(".")[0]
    if (CDPAddrRecordIPv4 in pkt):
      ip=pkt["CDPAddrRecordIPv4"].addr
    return "Device: {0} IP: {1}".format(hostname,ip)

interface="VirtualBox Host-Only Ethernet Adapter"
capturefilter="ether dst 01:00:0c:cc:cc:cc"

# run it for max. 99 Packets
p=sniff(prn=cdp_monitor_callback, iface=interface, count=99, filter=capturefilter, store=0)

Real-Life Example

Run this script:

C:\RH>python
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:59:51) [MSC v.1914 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> #! /usr/bin/env python
... from scapy.all import *
>>> load_contrib("cdp")
>>>
>>> def cdp_monitor_callback(pkt):
...   ip = "0.0.0.0"
...   if (CDPMsgDeviceID in pkt):
...     device=pkt["CDPMsgDeviceID"].val.decode()
...     hostname=device.split(".")[0]
...     if (CDPAddrRecordIPv4 in pkt):
...       ip=pkt["CDPAddrRecordIPv4"].addr
...     return "Device: {0} IP: {1}".format(hostname,ip)
...
>>> interface="VirtualBox Host-Only Ethernet Adapter"
>>> capturefilter="ether dst 01:00:0c:cc:cc:cc"
>>>
>>> # run it for max. 99 Packets
... p=sniff(prn=cdp_monitor_callback, iface=interface, count=99, filter=capturefilter, store=0)

Open another CMD-Window to spin up a new CSR1000V-Router:

C:\RH\work\entwicklung\csr1000v-provision-in-virtualbox>CSR1000v-Virtual-Box.cmd
Enter CSR1000v Hostname:CSR-CDPTEST-A
Virtual machine 'CSR-CDPTEST-A' is created and registered.
UUID: eaa931bd-9db4-4a78-b263-754d4bb300a0
Settings file: 'c:\RH\LAB\VM\CSR-CDPTEST-A\CSR-CDPTEST-A.vbox'
Creating ISO image at c:\RH\LAB\VM\CSR-CDPTEST-A\config.iso, 1 Files, Size: 8,00 KB
100%
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%
Medium created. UUID: 3019216e-2e61-435a-95f2-3d26312c3ed9
Waiting for VM "CSR-CDPTEST-A" to power on...
VM "CSR-CDPTEST-A" has been successfully started.

Go back to the „python“-Screen and wait:

>>> # run it for max. 99 Packets
... p=sniff(prn=cdp_monitor_callback, iface=interface, count=99, filter=capturefilter, store=0)
Device: CSR-CDPTEST-A IP: 0.0.0.0
Device: CSR-CDPTEST-A IP: 0.0.0.0
Device: CSR-CDPTEST-A IP: 0.0.0.0
Device: CSR-CDPTEST-A IP: 0.0.0.0
Device: CSR-CDPTEST-A IP: 0.0.0.0
Device: CSR-CDPTEST-A IP: 10.0.2.15
Device: CSR-CDPTEST-A IP: 10.0.2.15
Device: CSR-CDPTEST-A IP: 10.0.2.15

It works, the IOS-XE CSR1000V-Router is installed and it got it’s baseline-config applied:

Hostname
Interface set to „ip address dhcp“
CDP enabled

takes some time, but these first CDP-Packets captured were not sent in 60s interval, so don’t be scared 😉

2018-10-312018-10-30

Python Scapy: Capturing „Cisco Discovery Protocol (CDP)“

It’s hard to believe, how easy it is to capture (and to craft) LAN-Data using Python Scapy.

I need to capture CDP-Packets and to extract information like the hostname of the sender and it’s IP-Address.

As an modification of the „ARP-Monitor“-example taken from the manual Using scapy in your tools.

Scapy Installation

nothing special: pip install

C:\RH>pip install scapy
Collecting scapy
  Downloading https://files.pythonhosted.org/packages/68/01/b9943984447e7ea6f8948e90c1729b78161c2bb3eef908430638ec3f7296/scapy-2.4.0.tar.gz (3.1MB)
    100% |████████████████████████████████| 3.1MB 420kB/s
  In the tar file C:\Users\RONALD~1.HEI\AppData\Local\Temp\pip-unpack-4jm9kde1\scapy-2.4.0.tar.gz the member scapy-2.4.0/README is invalid: unable to resolve link inside archive
Installing collected packages: scapy
  Running setup.py install for scapy ... done
Successfully installed scapy-2.4.0

Python: Install Scapy

C:\RH>python
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:59:51) [MSC v.1914 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.

>>> from scapy.all import *

Example: List all Interfaces of my Laptop

>>> ifaces
INDEX  IFACE                                     IP            MAC
20     VirtualBox Host-Only Ethernet Adapter     192.168.56.1  0A:00:27:00:00:14
22     Intel(R) Dual Band Wireless-AC 8265       172.20.10.2   IntelCor:BD:10:37
4      Intel(R) Ethernet Connection (4) I219-LM  47.11.17.10   BayNetwo:00:DE:11

>>> for i in ifaces.data.keys():
...     iface = ifaces.data[i]
...     name = str(iface.name)
...     wname = iface.data['netid']
...     mac = str(iface.mac)
...     ip  = str(iface.ip)
...     print("DESCR:{0}, NAME:{1}, MAC:{2}, IP:{3}".format(wname,name,mac,ip))
...
DESCR:Wi-Fi, NAME:Intel(R) Dual Band Wireless-AC 8265, MAC:74:70:FD:BD:10:37, IP:172.20.10.2
DESCR:VirtualBox Host-Only Network, NAME:VirtualBox Host-Only Ethernet Adapter, MAC:0A:00:27:00:00:14, IP:192.168.56.1
DESCR:ETH_DELL, NAME:Intel(R) Ethernet Connection (4) I219-LM, MAC:00:00:81:00:DE:11, IP:47.11.17.10

Capture 10 Packets on a specific interface

The "NAME" is needed as interface-handle
>>> interface="VirtualBox Host-Only Ethernet Adapter"

>>> p=sniff(iface=interface, count=10)
>>> p.display()
0000 Ether / IP / UDP 192.168.56.1:17500 > 255.255.255.255:17500 / Raw
0001 Ether / IP / UDP 192.168.56.1:17500 > 255.255.255.255:17500 / Raw
0002 Ether / IP / UDP 192.168.56.1:17500 > 192.168.56.255:17500 / Raw
0003 Ether / IP / UDP 192.168.56.1:17500 > 255.255.255.255:17500 / Raw
0004 Ether / IP / UDP 192.168.56.1:17500 > 255.255.255.255:17500 / Raw
0005 Ether / IP / UDP 192.168.56.100:bootps > 255.255.255.255:bootpc / BOOTP / DHCP
0006 Ether / IP / UDP 192.168.56.102:50472 > 255.255.255.255:10067 / Raw
0007 Ether / IP / UDP 192.168.56.103:49580 > 255.255.255.255:10067 / Raw
0008 Ether / IP / UDP 192.168.56.1:17500 > 255.255.255.255:17500 / Raw
0009 Ether / IP / UDP 192.168.56.1:17500 > 255.255.255.255:17500 / Raw

Capture CDP-Packets

Capture CDP

>>> p=sniff(iface=interface, count=2, filter="ether dst 01:00:0c:cc:cc:cc")
>>> p
<Sniffed: TCP:0 UDP:0 ICMP:0 Other:2>
>>> p.display()
0000 802.3 08:00:27:c9:d5:7e > 01:00:0c:cc:cc:cc / LLC / SNAP / Raw
0001 802.3 08:00:27:c9:d5:7e > 01:00:0c:cc:cc:cc / LLC / SNAP / Raw

Decode CDP (with inactive dissector)

>>> p[0].display()
###[ 802.3 ]###
  dst       = 01:00:0c:cc:cc:cc
  src       = 08:00:27:c9:d5:7e
  len       = 386
###[ LLC ]###
     dsap      = 0xaa
     ssap      = 0xaa
     ctrl      = 3
###[ SNAP ]###
        OUI       = 0xc
        code      = 0x2000
###[ Raw ]###
           load      = '\x02\xb4\x91\x18\x00\x01\x00\x13CSR-A.lab.local\x00\x05\x01\x05Cisco IOS Software [Fuji], Virtual XE Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Version 16.9.1, RELEASE SOFTWARE (fc2)\nTechnical Support: http://www.cisco.com/techsupport\nCopyright (c) 1986-2018 by Cisco Systems, Inc.\nCompiled Tue 17-Jul-18 16:57 by mcpre\x00\x06\x00\x12cisco CSR1000V\x00\x02\x00\x11\x00\x00\x00\x01\x01\x01\xcc\x00\x04\xc0\xa88e\x00\x03\x00\x14GigabitEthernet2\x00\x04\x00\x08\x00\x00\x00!\x00\x07\x00\t\n\x00\x02\x00\x18\x00\x0b\x00\x05\x01\x00\x16\x00\x11\x00\x00\x00\x01\x01\x01\xcc\x00\x04\xc0\xa88e'

Activate the CDP-Parser

>>> list_contrib()
avs                 : AVS WLAN Monitor Header                  status=loads
bgp                 : BGP v0.1                                 status=loads
carp                : CARP                                     status=loads
cdp                 : Cisco Discovery Protocol                 status=loads
chdlc               : Cisco HDLC and SLARP                     status=loads
coap                : Constrained Application Protocol (CoAP)  status=loads
diameter            : Diameter                                 status=loads
dtp                 : DTP                                      status=loads
eigrp               : EIGRP                                    status=loads
etherip             : EtherIP                                  status=loads
gsm_um              : PPI                                      status=loads
gtp                 : GTP                                      status=loads
gtp_v2              : GTPv2                                    status=loads
homeplugav          : HomePlugAV Layer                         status=loads
http2               : HTTP/2 (RFC 7540, RFC 7541)              status=loads
icmp_extensions     : ICMP Extensions                          status=loads
igmp                : IGMP/IGMPv2                              status=loads
igmpv3              : IGMPv3                                   status=loads
ikev2               : IKEv2                                    status=loads
isis                : ISIS                                     status=loads
ldp                 : Label Distribution Protocol (LDP)        status=loads
lldp                : LLDP                                     status=loads
macsec              : -                                        status=?
modbus              : ModBus Protocol                          status=loads
mpls                : MPLS                                     status=loads
mqtt                : -                                        status=?
nsh                 : NSH Protocol                             status=loads
openflow            : Openflow v1.0                            status=loads
openflow3           : Openflow v1.3                            status=loads
ospf                : OSPF                                     status=loads
pnio                : ProfinetIO base layer                    status=loads
pnio_rtc            : ProfinetIO Real-Time Cyclic (RTC)        status=loads
ppi                 : PPI                                      status=loads
ppi_cace            : PPI CACE                                 status=loads
ppi_geotag          : PPI GEOLOCATION                          status=loads
ripng               : RIPng                                    status=loads
rsvp                : RSVP                                     status=loads
sebek               : Sebek                                    status=loads
send                : Secure Neighbor Discovery (SEND) (ICMPv6) status=loads
skinny              : Skinny Call Control Protocol (SCCP)      status=loads
spbm                : SBPM                                     status=loads
tacacs              : TACACS+ Protocol                         status=loads
tzsp                : TZSP                                     status=loads
ubberlogger         : Ubberlogger dissectors                   status=loads
vqp                 : VLAN Query Protocol                      status=loads
vtp                 : VLAN Trunking Protocol (VTP)             status=loads
wpa_eapol           : WPA EAPOL dissector                      status=loads

>>> load_contrib("cdp")

Capture again and display CDP-Information as cleartext

>>> load_contrib("cdp")

>>> p=sniff(iface=interface, count=1, filter=capturefilter)
>>>
>>>
>>> p[0].show()
###[ 802.3 ]###
  dst       = 01:00:0c:cc:cc:cc
  src       = 08:00:27:c9:d5:7e
  len       = 386
###[ LLC ]###
     dsap      = 0xaa
     ssap      = 0xaa
     ctrl      = 3
###[ SNAP ]###
        OUI       = 0xc
        code      = 0x2000
###[ Cisco Discovery Protocol version 2 ]###
           vers      = 2
           ttl       = 180
           cksum     = 0x9118
           \msg       \
            |###[ Device ID ]###
            |  type      = Device ID
            |  len       = 19
            |  val       = 'CSR-A.lab.local'
            |###[ Software Version ]###
            |  type      = Software Version
            |  len       = 261
            |  val       = 'Cisco IOS Software [Fuji], Virtual XE Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Version 16.9.1, RELEASE SOFTWARE (fc2)\nTechnical Support: http://www.cisco.com/techsupport\nCopyright (c) 1986-2018 by Cisco Systems, Inc.\nCompiled Tue 17-Jul-18 16:57 by mcpre'
            |###[ Platform ]###
            |  type      = Platform
            |  len       = 18
            |  val       = 'cisco CSR1000V'
            |###[ Addresses ]###
            |  type      = Addresses
            |  len       = 17
            |  naddr     = 1
            |  \addr      \
            |   |###[ CDP Address IPv4 ]###
            |   |  ptype     = NLPID
            |   |  plen      = 1
            |   |  proto     = '\xcc'
            |   |  addrlen   = 4
            |   |  addr      = 192.168.56.101
            |###[ Port ID ]###
            |  type      = Port ID
            |  len       = 20
            |  iface     = 'GigabitEthernet2'
            |###[ Capabilities ]###
            |  type      = Capabilities
            |  len       = 8
            |  cap       = Router+IGMPCapable
            |###[ IP Prefix ]###
            |  type      = IP Prefix
            |  len       = 9
            |  defaultgw = 10.0.2.0
            |###[ CDP Generic Message ]###
            |  type      = 0x1800
            |  len       = 2816
            |  val       = '\x05\x01\x00\x16\x00\x11\x00\x00\x00\x01\x01\x01\xcc\x00\x04\xc0\xa88e'

Decode CDP-Hostname

>>> device=p[0]["CDPMsgDeviceID"].val.decode()
>>> device
'CSR-A.lab.local'
>>> hostname=device.split(".")[0]
>>> hostname
'CSR-A'

Decode CDP-Management-IP-Address

>>> ip=p[0]["CDPAddrRecordIPv4"]
>>> ip.addr
'192.168.56.101'