Range / CIDR conversion utility

[coderholic]

Another utility that it'd be great to add to the cli is the ability to convert from cidr to start,end ranges. We commonly do this internally at IPinfo, and our customers sometimes need to do it with our data exports too.

Eg. input:
1.1.1.0,1.1.1.255,other data

Output:
1.1.1.0/24,other data

And vice versa. Should probably support a different range sepator too (eg. 1.1.1.0-1.1.1.255).

[UmanShahzad]

I think we have almost all the base code needed to do this already so that should be good!

[UmanShahzad]

Any idea for the name of a tool like this? This would also be the subcommand.

Some ideas:

• cidrconvert
• cidrconv
• cc

[UmanShahzad]

Or two tools that do each separately:

• cidr2range
• range2cidr

[coderholic]

Yeah I like 2 tools named cidr2range and range2cidr

[UmanShahzad]

Great, those names might also be easier to get & discover on distribution repos like homebrew/apt.

[UmanShahzad]

@coderholic A question about ranges that don't combine nicely into a single CIDR:

What to do about a range like 1.1.1.0,1.1.1.2 which really requires 2 CIDRs 1.1.1.0/31 and 1.1.1.2/32? (Obviously the other way around is not a problem.)

[UmanShahzad]

Just print both, and if so with a comma delimiter between them? Or skip these cases by default with a flag to force outputting multiple CIDRs if necessary?

[UmanShahzad]

For reference, we had a chat and the answer is if we encounter input like:

1.1.1.0,1.1.1.2,other data

we'd output the 2 CIDR result as:

1.1.1.0/31,other data
1.1.1.2/32,other data

i.e. copying the surrounding data per CIDR.

[UmanShahzad]

This'll be available in the v2 release fairly soon. Just wrapping it up.

[UmanShahzad]

When it's released, if there are any other issues let's make new issues for it.

[yermulnik]

Are there Hombrew tap issues to track progress on adding cidr2range and range2cidr? I can't see these in https://github.com/ipinfo/homebrew-tap so assumed you've gone with adding them to Homebrew tap at once.

[UmanShahzad]

I'll make PRs for getting these on the official homebrew tap tomorrow my time, yes. No point really adding them to the IPinfo tap at this point since it'll be replaced pretty quickly I reckon, given the good feedback we got from the homebrew guys on the previous stuff.

[UmanShahzad]

Made PRs for Homebrew:

cidr2range: Homebrew/homebrew-core#78164
range2cidr: Homebrew/homebrew-core#78166

[yermulnik]

Awesome 🥳 Thanks a lot!