Produce a "CIDR report" from Netbox

global_address_report.py

#!/usr/bin/env python3

# quick hacky script to produce a "CIDR report" of your global address space from Netbox
# this is released to the public domain, free of copyright and licensing.

# by Paul Sherratt


import urllib3
urllib3.disable_warnings()

import requests
import pynetbox

from netaddr import IPNetwork, IPAddress, IPSet

NETBOX_URL='https://netbox'
NETBOX_TOKEN=''


session = requests.Session()
session.verify = False
nb = pynetbox.api(NETBOX_URL, NETBOX_TOKEN)
nb.http_session = session

aggregates = nb.ipam.aggregates.filter(family=4, rir__n='private')
aggregates = {agg.prefix: {} for agg in aggregates}


roles = {}
total_addresses = 0

for aggregate, data in aggregates.items():
  prefix, prefix_length = aggregate.split('/')
  prefix_length = int(prefix_length)
  data['addresses'] = 2**(32-prefix_length)
  data['prefixes'] = list(nb.ipam.prefixes.filter(family=4, within=aggregate, status__n='container'))
  total_addresses += data['addresses']

for aggregate, data in aggregates.items():
  prefixes = {IPNetwork(p.prefix): str(p.role) for p in data['prefixes']}
  data['ipset'] = IPSet()
  last_network = 0
  for prefix, role in prefixes.items():
    if prefix.network == last_network:  # ignore duplicate entries
      continue
    last_network = prefix.network
    data['ipset'].add(prefix)
    if role not in roles:
      roles[role] = 0
    roles[role] += 2**(32-prefix.prefixlen)
  data['gaps'] = IPSet(IPNetwork(aggregate)) - data['ipset']


def cidr_report(prefix_length):
  count = 0
  for data in aggregates.values():
    for network in data['gaps'].iter_cidrs():
      if network.prefixlen <= prefix_length:
        count += 2**(prefix_length-network.prefixlen)
  return count

def print_report():
  print("Addresses Total:", total_addresses)
  print("Addresses Allocated:", sum(roles.values()))
  print("Addresses Free:", total_addresses - sum(roles.values()))
  print()
  print("Addresses Allocated Per Role:")
  for role in sorted(roles.keys()):
    print(f"  {role}: {roles[role]}")
  print()
  print("CIDR Report - Free Address Blocks:")
  for x in range(23,33):
    print(f"  /{x}: {cidr_report(x)}")


print_report()