Do not follow CNAME records for ANY or CNAME queries

[miodvallat]

Short description

This is an attempt at fixing #5769 (not addressing the RRSIG concern at the moment, though).

Disclaimer: I have no idea what I am doing.

Checklist

I have:

• read the CONTRIBUTING.md document
• compiled this code
• tested this code
• included documentation (including possible behaviour changes)
• documented the code
• added or modified regression test(s)
• added or modified unit test(s)

[coveralls]

Pull Request Test Coverage Report for Build 12887559896

Details

• 3 of 7 (42.86%) changed or added relevant lines in 1 file are covered.
• 5187 unchanged lines in 72 files lost coverage.
• Overall coverage decreased (-3.0%) to 61.744%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pdns/packethandler.cc	3	7	42.86%

Files with Coverage Reduction	New Missed Lines	%
modules/gpgsqlbackend/gpgsqlbackend.cc	1	88.62%
modules/pipebackend/coprocess.hh	1	0.0%
modules/gsqlite3backend/gsqlite3backend.cc	2	94.44%
pdns/recursordist/sortlist.cc	2	72.94%
ext/lmdb-safe/lmdb-typed.hh	2	71.86%
pdns/webserver.hh	3	66.36%
pdns/dnspacket.hh	3	77.78%
pdns/remote_logger.cc	3	53.81%
pdns/auth-zonecache.cc	3	91.07%
pdns/distributor.hh	3	50.62%

Totals
Change from base Build 12884379895:	-3.0%
Covered Lines:	122613
Relevant Lines:	166406

---

💛 - Coveralls

[Habbie]

not addressing the RRSIG concern at the moment, though

reading back what I wrote there, it turns out I did not include enough information for anybody (including myself) to see what that was about. In any case the RRSIG behaviour I see today (without your PR) looks just fine.

[Habbie]

This patch looks right. I wonder if any the wildcard, LUA and DNAME paths contain a similar bug, though. But this is an improvement in any case. Can you add a test?

[miodvallat]

Can you add a test?

I am struggling with getting the existing tests to pass at the moment - a couple of the existing tests need oracle changes, but then further steps in the CI fail because they reuse the same tests and apparently don't need any change...

[Habbie]

this extra output is unexpected. If anything I would expect some responses to become smaller!

[Habbie]

i wonder if we should be setting weDone when we match-but-don't-follow a CNAME?