1b1088d52f test: add combined I2P/onion/localhost eviction protection tests (Jon Atack)
7c2284eda2 test: add tests for inbound eviction protection of I2P peers (Jon Atack)
ce02dd1ef1 p2p: extend inbound eviction protection by network to I2P peers (Jon Atack)
70bbc62711 test: add combined onion/localhost eviction protection coverage (Jon Atack)
045cb40192 p2p: remove unused m_is_onion member from NodeEvictionCandidate struct (Jon Atack)
310fab4928 p2p: remove unused CompareLocalHostTimeConnected() (Jon Atack)
9e889e8a5c p2p: remove unused CompareOnionTimeConnected() (Jon Atack)
787d46bb2a p2p: update ProtectEvictionCandidatesByRatio() doxygen docs (Jon Atack)
1e15acf478 p2p: make ProtectEvictionCandidatesByRatio() fully ratio-based (Jon Atack)
3f8105c4d2 test: remove combined onion/localhost eviction protection tests (Jon Atack)
38a81a8e20 p2p: add CompareNodeNetworkTime() comparator struct (Jon Atack)
4ee7aec47e p2p: add m_network to NodeEvictionCandidate struct (Jon Atack)
7321e6f2fe p2p, refactor: rename vEvictionCandidates to eviction_candidates (Jon Atack)
ec590f1d91 p2p, refactor: improve constness in ProtectEvictionCandidatesByRatio() (Jon Atack)
4a19f501ab test: add ALL_NETWORKS to test utilities (Jon Atack)
519e76bb64 test: speed up and simplify peer_eviction_test (Jon Atack)
1cde800523 p2p, refactor: rm redundant erase_size calculation in SelectNodeToEvict() (Jon Atack)
Pull request description:
Continuing the work in #20197 and #20685, this pull updates and abstracts our inbound eviction protection to make it fully ratio-based and easily extensible to peers connected via high-latency privacy networks that we newly support, like I2P and perhaps others soon, as these peers are disadvantaged by the latency criteria of our eviction logic.
It then adds eviction protection for peers connected over I2P. As described in https://github.com/bitcoin/bitcoin/pull/20685#issuecomment-767486499, we've observed over the past few months that I2P peers have a min ping latency similar to or greater than that of onion peers.
The algorithm is a basically a multi-pass knapsack:
- Count the number of eviction candidates in each of the disadvantaged
privacy networks.
- Sort the networks from lower to higher candidate counts, so that
a network with fewer candidates will have the first opportunity
for any unused slots remaining from the previous iteration. In
the case of a tie in candidate counts, priority is given by array
member order from first to last, guesstimated to favor more unusual
networks.
- Iterate through the networks in this order. On each iteration,
allocate each network an equal number of protected slots targeting
a total number of candidates to protect, provided any slots remain
in the knapsack.
- Protect the candidates in that network having the longest uptime,
if any in that network are present.
- Continue iterating as long as we have non-allocated slots
remaining and candidates available to protect.
The goal of this logic is to favorise the diversity of our peer connections.
The individual commit messages describe each change in more detail.
Special thank you to Vasil Dimov for the excellent review feedback and the algorithm improvement that made this change much better than it would have been otherwise. Thanks also to Antoine Riard, whose review feedback nudged this change to protect disadvantaged networks having fewer, rather than more, eviction candidates.
ACKs for top commit:
laanwj:
Code review re-ACK 1b1088d52f
vasild:
ACK 1b1088d52f
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