fix: lock-free counters for auth_zone up/down queries

[sakateka]

It is simplified version of #1160

[gthess]

Hi @sakateka, sorry for the delayed response.

Removing the lock for authzones in #1160 is not a desired feature because the lock is needed during operation to handle zone updates with XFR for example. So I would like to close that PR if you don't mind :)

I like the idea of moving the authzone counters out of locks but putting them in worker->stats is not the correct solution because when libunbound is used(the library not the binary), there is no server worker that has stats and that would eventually lead to a crash. I am talking about accessing counters through env->stats from iterator.c and authzone.c.

If you would like to rework the PR you could put the counters in mesh_area and you could follow the paradigm of mesh_area->ans_expired for example.

[sakateka]

when libunbound is used(the library not the binary), there is no server worker that has stats

Indeed, I missed it, thank you!
I'll rework the PR.

[sakateka]

Hi @gthess, it seems I didn't mess up anything and did everything right this time.
Take a look at this version of the patch, please.

[gthess]

Looking good!
Just a small change and this can be merged.

[gthess]

Not necessarily needed in this case but for consistency with other mesh-> values these should be added.
The else is not needed since the worker stats are initialized and reset based on configuration.

Suggested change

	s->svr.num_query_authzone_up = (long long)worker->env.mesh->num_query_authzone_up;
	s->svr.num_query_authzone_down = (long long)worker->env.mesh->num_query_authzone_down;
	} else {
	s->svr.num_query_authzone_up = 0;
	s->svr.num_query_authzone_down = 0;
	s->svr.num_query_authzone_up += (long long)worker->env.mesh->num_query_authzone_up;
	s->svr.num_query_authzone_down += (long long)worker->env.mesh->num_query_authzone_down;

[sakateka]

fixed

[gthess]

Thanks! Now counting for auth_zone stats can happen lock free per thread and the values can be aggregated for the stat commands.