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 12595938391

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 11541 unchanged lines in 185 files lost coverage.
• Overall coverage increased (+2.5%) to 62.775%

---

Files with Coverage Reduction	New Missed Lines	%
pdns/dnsdistdist/dnsdist-session-cache.cc	1	62.86%
pdns/comment.hh	1	0.0%
pdns/recursordist/nod.hh	1	92.59%
pdns/base64.cc	1	80.6%
pdns/test-dnsrecords_cc.cc	2	95.97%
pdns/query-local-address.cc	2	89.36%
pdns/auth-packetcache.cc	2	74.35%
pdns/epollmplexer.cc	2	83.75%
pdns/recursordist/negcache.hh	2	88.24%
pdns/recursordist/rec-tcpout.cc	2	63.49%

Totals
Change from base Build 12589349850:	2.5%
Covered Lines:	105832
Relevant Lines:	138350

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💛 - 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...