python-hexroute

Summary

This is a python version of the original bash hexroute script (availble here).

Installation

Just download and run the script:

wget https://raw.githubusercontent.com/musashiXXX/python-hexroute/main/hexroute.py
chmod 755 hexroute.py
./hexroute.py

Or install it via pipenv to be used as a module:

pipenv install -e git+https://github.com/musashiXXX/python-hexroute.git#egg=python-hexroute

Usage

usage: hexroute.py [-h] (-r 192.168.0.0/16 192.168.0.1 | -R 18:C0:A8:64:C0:A8:64:01)

Generate or parse a DHCP option 121/249 hexadecimal string

optional arguments:
  -h, --help            show this help message and exit
  -r 192.168.0.0/16 192.168.0.1, --route 192.168.0.0/16 192.168.0.1
                        Specify a network/gateway pair
  -R 18:C0:A8:64:C0:A8:64:01, --reverse 18:C0:A8:64:C0:A8:64:01
                        Convert an option 121/249 hex string into IPv4 network/route pairs

Generate a hex string:

./hexroute.py -r 10.10.10.0/24 192.168.0.1 -r 172.16.0.0/12 192.168.0.1
18:0A:0A:0A:C0:A8:00:01:0C:AC:10:C0:A8:00:01

Parse a hex string:

./hexroute.py -R '18:0A:0A:0A:C0:A8:00:01:0C:AC:10:C0:A8:00:01'
[(IPv4Network('10.10.10.0/24'), IPv4Address('192.168.0.1')), (IPv4Network('172.16.0.0/12'), IPv4Address('192.168.0.1'))]

References

• RFC 3442
• 2.2.8 DHCPv4 Option Code 249 (0xF9) - Microsoft Classless Static Route Option
• How to push static routes from the Palo Alto Networks DHCP Server

  • Linux will accept routes learned through DHCP Option 121 and Option 249. if it doesn not, set option classless_static_routes in /etc/dhcpcd.conf. If both options are configured, Linux will prefer routes defined by DHCP Option 121.