Start API on both IPv4 and IPv6

[Rishi556]

Checklist

• My issue is specific & actionable.
• I am not suggesting a protocol enhancement.
• I have searched on the issue tracker for my issue.

Description

By default, Kubo only listens on 127.0.0.1:5001 for api connections. With IPv6 usage growing, listening on [::1]:5001 as well should be default behavior.

[Jorropo]

It's localhost, I don't belive this is an issue.

It's still intresting to solve just because we would need to make API accept a list of listeners (it might already idk).

[Rishi556]

It does cause issues since Node.js uses IPv6 for localhost by default (dns is verbatim from os, not reordered to have IPv4 at the start) from version 18 onward. It would be helpful for Kubo to listen on both stacks to ensure that doesn't cause problems for anyone else like it did for me.

[Jorropo]

I'm surprised that nodejs does this, ¯\_(ツ)_/¯ I guess we gotta fix this then.

[Rishi556]

This looks like it's pretty simple to fix, by changing the Addresses section of the config to have an array of addresses with both v4 and v6. I'll see if I can find where in the code this is done at.

  "Addresses": {
    "API": ["/ip4/127.0.0.1/tcp/5001", "/ip6/::1/tcp/5001"],
    "Gateway": ["/ip4/127.0.0.1/tcp/8080","/ip6/::1/tcp/8080"]
  }

[lidel]

Exposing more than one listener is blocked by two bugs:

• corehttp/metrics.go: ERROR with more than one RPC API listener #9397
• An error has occurred while serving routing_http_client metrics #9891

We need to solve them first, before merging #9788