net: Continuous ASMap health check #27581

There are certain statistics we can collect by running all our known clearnet addresses against the ASMap file. This could show issues with a maliciously manipulated file or with an old file that has decayed with time.

This is just a proof of concept for now. My idea currently is to run the analysis once per day and print the results to logs if an ASMap file is used.

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• #28690 (build: Introduce internal kernel library by TheCharlatan)
• #27600 (net: Add new permission forceinbound to evict a random unprotected connection if all slots are otherwise full by pinheadmz)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

Concept ACK.

I think this is ready for review. I have included the feedback so far and I think the current extent of the checks and stats is good enough as a first step. I am currently still going through all the possible cases we could see an ASMap file be harmful to a node and this may lead to some additional checks and stats being logged in the future but I need some more time for this and it can be done as a follow-up.

Concept ACK.

Concept ACK, but I'm not conviced about the approach.

In 9b1d32e203435a62caef7079fe8c49f755b43e3d "Net: Add continuous ASMap health check logging": You're basically fetching all addresses (ipv4/ipv6) from addrman and doing a sanity check every 24hs. Considering we don't change asmap file frequently (we need to restart the node to do it), do we really need to do it for all addresses every 24hs?

Perhaps we could do it when:

• Node is starting (it happens in this current implementation because of OpenThreadConnection) - this is the only situation where asmap file can be changed
• Every time we are going to add an address to addrman's new table?

My idea currently is to run the analysis once per day

Instead of creating m_last_asmap_health_check and putting the logic into ThreadOpenConnection. Why not creating ASMapHealthCheck in CConnman:

void CConnman::ASMapHealthCheck()
{
    const std::vector<CAddress> v4_addrs{GetAddresses(0, 0, Network::NET_IPV4)};
    const std::vector<CAddress> v6_addrs{GetAddresses(0, 0, Network::NET_IPV6)};
    std::vector<CNetAddr> clearnet_addrs;
    clearnet_addrs.reserve(v4_addrs.size() + v6_addrs.size());
    std::transform(v4_addrs.begin(), v4_addrs.end(), std::back_inserter(clearnet_addrs),
        [](const CAddress& addr) { return static_cast<CNetAddr>(addr); });
    std::transform(v6_addrs.begin(), v6_addrs.end(), std::back_inserter(clearnet_addrs),
        [](const CAddress& addr) { return static_cast<CNetAddr>(addr); });
    m_netgroupman.ASMapHealthCheck(clearnet_addrs);
}

and then you could do in CConnman::Start something like:

if (m_netgroupman.UsingASMap()) {
    scheduler.scheduleFromNow([this] { ASMapHealthCheck(); }, ASMAP_HEALTH_CHECK);
}

being ASMAP_HEALTH_CHECK the period, e.g.:

static constexpr std::chrono::hours ASMAP_HEALTH_CHECK{24};

Obs: I didn't test it, just a suggestion that came to my mind.

@brunoerg Thanks for the review! I like the idea of using the scheduler and I applied that change. However, I am unsure about tying the check to adding new addresses to the new table. It seems arbitrary to put it there, I would also like to run it on removals if we were going this route. From looking at some debug logs from a node I resynced the day before, I see changes in the address tables happening every couple of minutes. So we would still need to track the elapsed time to not run the check more often than necessary. So I think just using the 24h scheduler is cleaner and just as good.

So we would still need to track the elapsed time to not run the check more often than necessary. So I think just using the 24h scheduler is cleaner and just as good.

I agree.

Addressed the feedback and rebased, which seems to have fixed the CI issues finally.

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Rebased and addressed feedback from @brunoerg and @mzumsande . After some offline discussion with @mzumsande I have added the possibility to use GetAddr() unfiltered, i.e. with isTerrible() = true addresses. Otherwise, the results are not as expressive as I would have liked but happy to bikeshed this if people have different opinions :)

Rebased

CI times out

CI times out

Doesn't really look related? One failed after 120m, one after 16s and most succeeded. I also don't see any relation to test changes here. Pushed a new rebase to see if the issues persist...

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code lgtm, will test in practice soon!

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