libnetwork/resolvconf: filter out ipv6 link local

[Luap99]

One thing I noticed in the recent aardvark-dns bug[1] that we copy link local nameservers into the container. This makes no sense as the link local address contains a zone (interface name/index) and cannot work without it. However a container by design will have a different interface name/index so the address can never work in the normal case.

Only when we do share the host netns then we should keep it.

[1] https://github.com/containers/aardvark-dns/pull/537

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Luap99

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/containers/common/blob/main/OWNERS)~~ [Luap99] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[Luap99]

@mheon PTAL

[mheon]

LGTM, though I wonder if it's not time to start thinking about a proper parser for resolv.conf instead of regexes

[Luap99]

yeah I would like that too but that seems a lot work work and this here was a simple enough fix.

[rhatdan]

/lgtm