net/p5-Net-Netmask 2.0003 OpenBSD

Net::Netmask parses and understands IPv4 CIDR blocks. It's built with an object-oriented interface and provides nearly all bits of information about a network block that you might want.

There are also functions to put a network block into a table and look it up by IP address, turn an IP address range into a list of CIDR blocks, turn a list of CIDR blocks into a list of IP addresses, and a function for sorting by text IP address.