CIDR

Classless Inter-Domain Routing (CIDR) utilities for Elixir

Setup

To use this library in your project, edit your mix.exs file and add :cidr as a dependency:

defp deps do
  [
    {:cidr, ">= 1.0.0"}
  ]
end

Usage

When you pass in an IP address string into CIDR.parse, you get a %CIDR{} struct back. This contains the start and end addresses as Erlang IP tuples, the amount of hosts the range covers and the mask.

iex(1)> cidr = "1.2.3.4/24" |> CIDR.parse
%CIDR{first: {1, 2, 3, 0}, last: {1, 2, 3, 255}, hosts: 256, mask: 24}

You can query the struct for all of its fields:

iex(2)> cidr.first
{1, 2, 3, 0}
iex(3)> cidr.hosts
256

And use it to see if other IP addresses fall in the same range:

iex(4)> cidr |> CIDR.match!({1,2,3,100})
true
iex(5)> cidr |> CIDR.match!({1,2,4,1})
false

The match function also supports IP strings:

iex(6)> cidr |> CIDR.match!("1.2.3.100")
true
iex(7)> cidr |> CIDR.match!("1.2.4.1")
false

Keep in mind that match!/2 throws an ArgumentError when you pass in a value that does not represent a valid IP address or when you try to match an IPv4 address with an IPv6 range and vice-versa. We also provide match/2, a non- throwing interface that returns tagged tuples:

iex(8)> cidr |> CIDR.match("1.2.3.100")
{:ok, true}
iex(9)> cidr |> CIDR.match("1.2.4.1")
{:ok, false}
iex(10)> cidr |> CIDR.match("1.2.3.1000")
{:error, "Tuple is not a valid IP address."}

Contribution Process

This project uses the C4.1 process for all code changes.

"Everyone, without distinction or discrimination, SHALL have an equal right to become a Contributor under the terms of this contract."

TL;DR

1. Check for open issues or open a new issue to start a discussion around a feature idea or a bug.
2. Fork the cidr-elixir repository on GitHub to start making your changes.
3. Write a test which shows that the bug was fixed or that the feature works as expected
4. Send a pull request and wait for it to be merged

License

Mozilla Public License 2.0.