Remove interface names from ipv6

[JeroenED]

What does this PR do?

Fixes #7270

This PR removes the interfacename from an IpAddress before it gets parsed as net.ParseIP does not allow the interfacename to be there

Motivation

Frankly, this is pure self service. I was suffering from this issue myself and wanted to get it fixed.

More

• Added/updated tests
• Added/updated documentation

Additional Notes

I never wrote any golang code before so please allow if my code has done stuff that you should not do.

[jspdown]

Thanks @JeroenED for opening this PR.

There was indeed an issue with IPv6 zones. As you've identified, the problem comes from the net.ParseIP which doesn't support zones.
Internally, net.ParseIP relies on netip.ParseAddr which does support zones.

So, instead of removing the zone I would suggest to improve our helper function parseIP to do something like this, and use the helper in the NewChecker function.

func parseIP(addr string) (net.IP, error) {
	parsedAddr, err := netip.ParseAddr(addr)
	if err != nil {
		return nil, err
	}
	
	ip := parsedAddr.As16()
	return ip[:], nil
}

This would have the benefit of relying more on the standard library and providing better errors.

[JeroenED]

I changed the PR as requested. I did however retain the original error line

[jspdown]

I've tested the changes and successfully fixes the issue 👍
One last thing before I approve the PR, could you add a new test case in TestContainsIsAllowed?

[jspdown]

This should be net/netip

[JeroenED]

Hi,
Fixed the import and added 2 accept and reject test case.

[rtribotte]

Suggested change

	}
	}

[JeroenED]

Fixed it