The PySubnetTree package provides a Python data structure SubnetTreethat maps subnets given in CIDR notation (incl. corresponding IPv6versions) to Python objects. Lookups are performed by longest-prefixmatching.
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.
You can find the latest PySubnetTree release for download at http://www.bro.org/download.
This document describes PySubnetTree 0.26. See the CHANGES file for version history.
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 >>> 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
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.
This package requires Python 2.4 or newer.
Installation is pretty simple:
> python setup.py install