lua-libcidr-ffi

LuaJIT FFI bindings to libcidr. Provides CIDR calculations for IPv4 and IPv6.

Installation

The libcidr library must first be installed on your system. Then you can install lua-libcidr-ffi through LuaRocks:

$ luarocks install libcidr-ffi

Usage

local cidr = require "libcidr-ffi"
cidr.contains(cidr.from_str("10.10.10.10/8"), cidr.from_str("10.20.30.40")) -- true
cidr.contains(cidr.from_str("10.10.10.10/16"), cidr.from_str("10.20.30.40")) -- false
cidr.contains(cidr.from_str("2001:db8::/32"), cidr.from_str("2001:db8:1234::1")) -- true
cidr.contains(cidr.from_str("2001:db8::/32"), cidr.from_str("2001:db9:1234::1")) -- false

Functions

For more detailed documentation of function behavior, see libcidr's own documentation. Currently, only bindings to a few of libcidr's functions are available in this Lua library, but other bindings could easily be added.

from_str

struct, err = cidr.from_str(string)

Takes in a netblock description as a human-readable string, and creates a CIDR structure from it. In case of failures, returns nil and a string describing the error.

to_str

string, err = cidr.to_str(struct)

Takes in a CIDR structure, and generates up a human-readable string describing the netblock. In case of failures, returns nil and a string describing the error.

contains

bool = cidr.contains(big, small)

This function is passed two CIDR structures describing a pair of netblocks. It then determines if the latter is wholly contained within the former. In case of failures, returns nil and a string describing the error.

Alternatives

• lua-resty-iputils: A pure Lua library for CIDR comparisons in OpenResty. Provides a nice higher-level API with built-in caching. Currently lacks IPv6 support.