hmt-pysubnettree 0.38.1.dev5

Map subnets in CIDR notation to Python objects

The PySubnetTree package provides a Python data structure SubnetTree which maps subnets given in CIDR notation (incl. corresponding IPv6 versions) to Python objects. Lookups are performed by longest-prefix matching.

PySubnetTree should generally work on Unix-like platforms such as Linux, macOS, and FreeBSD, but does not support Windows.

Download

You can find the latest PySubnetTree release for download at https://www.zeek.org/download.

PySubnetTree’s git repository is located at https://github.com/zeek/pysubnettree

This document describes PySubnetTree 0.38.1-5. See the CHANGES file for version history.

Example

A simple example which associates CIDR prefixes with strings:

>>> import SubnetTree
>>> t = SubnetTree.SubnetTree()
>>> t["10.1.0.0/16"] = "Network 1"
>>> t["10.1.42.0/24"] = "Network 1, Subnet 42"
>>> print("10.1.42.1" in t)
True
>>> print(t["10.1.42.1"])
Network 1, Subnet 42
>>> print(t["10.1.43.1"])
Network 1
>>> print("10.20.1.1" in t)
False
>>> t.search_all("10.1.42.1")
['Network 1, Subnet 42', 'Network 1']
>>> try:
...     print(t["10.20.1.1"])
... except KeyError as err:
...     print("Error: %s not found" % err)
Error: '10.20.1.1' not found

PySubnetTree also supports IPv6 addresses and prefixes:

>>> import SubnetTree
>>> t = SubnetTree.SubnetTree()
>>> t["2001:db8::/32"] = "Company 1"
>>> t["2001:db8:4000::/48"] = "Company 1, Site 1"
>>> t["2001:db8:4000:abcd::"]
Company 1, Site 1
>>> t["2001:db8:fe:1234::"]
Company 1
>>> t.search_all("2001:db8:4000:abcd::1")
['Company 1, Site 1', 'Company 1']

By default, CIDR prefixes and IP addresses are given as strings. Alternatively, a SubnetTree object can be switched into binary mode, in which single addresses are passed in the form of packed binary strings as, e.g., returned by socket.inet_aton:

>>> t.get_binary_lookup_mode()
False
>>> t.set_binary_lookup_mode(True)
>>> t.get_binary_lookup_mode()
True
>>> import socket
>>> print(t[socket.inet_aton("10.1.42.1")])
Network 1, Subnet 42

A SubnetTree also provides methods insert(prefix,object=None) for insertion of prefixes (object can be skipped to use the tree like a set), and remove(prefix) for removing entries (remove performs an _exact_ match rather than longest-prefix).

Internally, the CIDR prefixes of a SubnetTree are managed by a Patricia tree data structure and lookups are therefore efficient even with a large number of prefixes.

PySubnetTree comes with a BSD license.

Prerequisites

This package requires Python 3.10 or newer.

Installation

Installation is pretty simple:

> python3 setup.py install

A PyPI package exists as well and can be installed via pip:

> pip3 install pysubnettree