pfctl: Fix recursive printing of anchor labels

[email_luiz.eng.br]

Summary

We recently noticed that the recursive printing of labels wasn't working like the recursive printing of rules.

When running pfctl -sr -a* we get a listing of all rules, including the ones inside anchors. On the other hand, when running pfctl -sl -a*, it would only print the labels in the root level, just like without the -a* argument.

As in our use-case we are interested on labels only and our labels are unique even between anchors, we didn't add indentation or hierarchy to the printing.

Sponsored by: InnoGames GmbH

Test Plan

Load a ruleset with anchors:

anchor lbpools_1 in on vtnet0 from any to 2001:db8::/32 {
  pass in quick proto tcp from any to port 443:443 label "pool_1237773_IPv6:$proto:$dstport"
  anchor "block" {
    block quick label "pool_1237773_IPv6:drop"
  }
}
pass quick from any to any label "anytoany"

Verify that pfctl -sl -a* will list all labels, including the ones inside the anchors:

# pfctl -sl -a*
pool_1237773_IPv6:tcp:443 0 0 0 0 0 0 0 0
pool_1237773_IPv6:drop 0 0 0 0 0 0 0 0
anytoany 0 0 0 0 0 0 0 0

instead of listing just the labels in the default level:

# pfctl -sl -a*
anytoany 0 0 0 0 0 0 0 0

[kp]

At first glance that looks fairly similar to other such fixes for rule and ethernet rule printing.
I'm going to need a bit more time to actually understand this fully though, the anchor code always gives me headaches.

In the mean time it'd be really nice if you could add a basic test case for this, otherwise we risk accidentally breaking this again at some point.

[email_luiz.eng.br]

I realized now that I forgot to send a reply here. I will write the tests sometime around this week and then send them on a new differential.
Thanks for the commit, @kp :)

[kp]

In D42728#975974, @email_luiz.eng.br wrote:

I realized now that I forgot to send a reply here. I will write the tests sometime around this week and then send them on a new differential.
Thanks for the commit, @kp :)

I included a basic test with the commit too: https://cgit.freebsd.org/src/commit/?id=1d723c1e565e714e4192883d813ef81e97220f27