lib/cache: no aggressive caching on minimal NSEC* ranges

We use packet cache instead. Also do the same on some kinds of weird RRsets, as even there some caching should be better than none at all. This "incidentally" works around all known cases of DVE-2018-0003.

changed the description

changed milestone to %4.1.0

assigned to @vcunat

marked as a Work In Progress

added 41 commits

• 3fe64455...ac789eba - 40 commits from branch master
• 04746fe4 - lib/cache: no aggressive caching on minimal NSEC* ranges

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CI shows significant decrease in answertype differences in all respdiffs. (Significant in relative numbers; it's just around a dozen or two.) It seems these are instances of that DVE, e.g.:

== Field "answertypes", mismatch "expected 'A' got ''" query details
    Count  Query
        1  home.chance.cz. A
        1  www.skontakt.cz. A
        1  kdejinde.cz. A
        1  adisepo.epo.mfcr.cz. A
        1  www.cezdistribuce.cz. A
        1  appft.uspto.gov. A
        1  adisdpr.epo.mfcr.cz. A

assigned to @ikrumlova

added 1 commit

• 3d55a1a6 - WIP: adding integration test from Ivana Krumlova

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marked as a Work In Progress from 3d55a1a6

added 19 commits

• 3d55a1a6...b2ad9443 - 17 commits from branch master
• f1be61dd - lib/cache: no aggressive caching on minimal NSEC* ranges
• f402b3d3 - tests: integration test for minimal NSEC3 range

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unmarked as a Work In Progress

added performance label

enabled an automatic merge when the pipeline for f402b3d3 succeeds

canceled the automatic merge

merged

mentioned in commit e4b7f259

@ikrumlova Thank you for the test!

mentioned in issue #509 (closed)

mentioned in issue #391

mentioned in issue #422 (closed)