dnsdist: add bloom filter accessible from Lua

[esensar]

Short description

Further extends #17561 with a bloom filter instead of a cache, allowing presence checks with a lower memory usage.

Checklist

I have:

• read the CONTRIBUTING.md document
• read and accepted the Developer Certificate of Origin document, including the AI Policy, and added a "Signed-off-by" to my commits
• 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)

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Sponsored by Quad9

[esensar]

This depends on #17561 - if and once that gets merged, I will rebase this.

[coveralls]

Coverage Report for CI Build 31519278567

Coverage increased (+1.4%) to 68.452%

Details

• Coverage increased (+1.4%) from the base build.
• Patch coverage: 28 uncovered changes across 1 file (104 of 132 lines covered, 78.79%).
• 3587 coverage regressions across 68 files.

Uncovered Changes

File	Changed	Covered	%
pdns/stable-bloom.hh	132	104	78.79%

Coverage Regressions

3587 previously-covered lines in 68 files lost coverage.

Top 10 Files by Coverage Loss	Lines Losing Coverage	Coverage
pdns/tcpiohandler.cc	521	27.26%
pdns/libssl.cc	500	6.54%
pdns/pkcs11signers.cc	484	0.42%
modules/bindbackend/bindbackend2.cc	286	35.96%
modules/lmdbbackend/lmdbbackend.cc	191	65.64%
pdns/misc.cc	180	50.25%
pdns/tcpiohandler.hh	179	30.41%
pdns/dnsparser.cc	135	72.87%
pdns/iputils.hh	115	68.44%
pdns/ws-auth.cc	113	76.7%

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Coverage Stats

Relevant Lines:	114392
Covered Lines:	85014
Line Coverage:	74.32%
Relevant Branches:	57406
Covered Branches:	32586
Branch Coverage:	56.76%
Branches in Coverage %:	Yes
Coverage Strength:	8935629.52 hits per line

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💛 - Coveralls

[edmonds]

It looks like there is a custom Bloom filter implementation in here. I would instead recommend the (heavily optimized and reviewed) Bloom filter that was added to Boost recently (https://www.boost.org/doc/libs/latest/libs/bloom/doc/html/bloom.html) even though it requires a more up-to-date Boost than is typically available in the stable distros.

[esensar]

It looks like there is a custom Bloom filter implementation in here. I would instead recommend the (heavily optimized and reviewed) Bloom filter that was added to Boost recently (https://www.boost.org/doc/libs/latest/libs/bloom/doc/html/bloom.html) even though it requires a more up-to-date Boost than is typically available in the stable distros.

Thanks for the suggestion. I just used the implementation that was already present and used in the project - seemed like the safest option.

[rgacogne]

I like the idea, and I agree using the existing implementation is the right thing to do (whether we might want to switch to the Boost one when available is a different discussion). Let's get #17561 merged first (I have been lagging behind, sorry about that).

[esensar]

Understood - sorry about all of these drafts, I wanted to get them in a reviewable state, because I have been dragging it around in WIP branches for some time.