Implement support for whitelists, default-deny/allow (rebase)

[bigs]

Rebasing #1 so that we can progress with it.

[bigs]

@vyzo can we take another pass on this?

[vyzo]

@bigs can you look at the comment about the potential bug?

[bigs]

@vyzo yeah, that was discussed in the original PR. i guess it's supposed to match the semantics of iptables

[prestonvanloon]

Is there any update here? We really need this for github.com/prysmaticlabs/prysm

[raulk]

@prestonvanloon thanks for raising the voice here. I've added this to my queue for tomorrow.

[ghost]

This looks good to me on a high level, I like that it keeps backward compatibility. 👏

Naming needs a cleanup, there's six names (block, reject, deny, allow, accept, whitelist) where two would be appropriate. Whitelist in particular isn't a good name because it's a metaphor that's easy to misunderstand or not understand at all.

There's also a bit of diff clutter because you renamed f to fs in some cases - it'll be easier to review without that rename. I'm fine with that type of change but it shouldn't be included in PRs that already contain significant changes on their own.

[raulk]

I'll take care of adjusting this PR in accordance with review feedback.

[raulk]

@lgierth @vyzo @bigs I've pushed some changes to bring consistency and nicer API. Is this something we're more keen to get behind?

Todo:

• taking account specificity when evaluating blocked addrs

[vyzo]

looks much better.

[raulk]

All done here. I've also reworked the commit history to group all contributions while retaining authorship.

[bigs]

LGTM! thanks @raulk!

[prestonvanloon]

Can this be merged?

[raulk]

@prestonvanloon yes, let's do that 👍

[raulk]

@prestonvanloon released in v0.0.2; update with gomod!