mirror of https://github.com/oxen-io/lokinet
* use weak_ptr on core rpc
* use reachability testing code lifted storage server's codepull/1659/head
Jeff Becker
3 years ago
parent
b830eeb535
commit
9ad90d029d
@ -0,0 +1,160 @@
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#include "reachability_testing.hpp"
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#include <chrono>
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#include <llarp/router/abstractrouter.hpp>
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#include <llarp/util/logging/logger.hpp>
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#include <llarp/crypto/crypto.hpp>
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using std::chrono::steady_clock;
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namespace llarp::consensus
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{
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namespace detail
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{
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std::mt19937_64&
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rng()
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{
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static thread_local std::mt19937_64 generator{std::random_device{}()};
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return generator;
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}
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} // namespace detail
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using fseconds = std::chrono::duration<float, std::chrono::seconds::period>;
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using fminutes = std::chrono::duration<float, std::chrono::minutes::period>;
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static void
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check_incoming_tests_impl(
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std::string_view name,
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const time_point_t& now,
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const time_point_t& startup,
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detail::incoming_test_state& incoming)
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{
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const auto elapsed = now - std::max(startup, incoming.last_test);
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bool failing = elapsed > reachability_testing::MAX_TIME_WITHOUT_PING;
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bool whine = failing != incoming.was_failing
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|| (failing && now - incoming.last_whine > reachability_testing::WHINING_INTERVAL);
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incoming.was_failing = failing;
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if (whine)
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{
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incoming.last_whine = now;
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if (!failing)
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{
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LogInfo(name, " ping received; port is likely reachable again");
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}
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else
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{
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if (incoming.last_test.time_since_epoch() == 0s)
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{
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LogWarn("Have NEVER received ", name, " pings!");
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}
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else
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{
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LogWarn(
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"Have not received ",
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name,
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" pings for a long time: ",
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fminutes{elapsed}.count(),
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" minutes");
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}
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LogWarn(
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"Please check your ",
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name,
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" port. Not being reachable "
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"over ",
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name,
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" may result in a deregistration!");
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}
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}
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}
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void
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reachability_testing::check_incoming_tests(const time_point_t& now)
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{
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check_incoming_tests_impl("lokinet", now, startup, last);
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}
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void
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reachability_testing::incoming_ping(const time_point_t& now)
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{
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last.last_test = now;
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}
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std::optional<RouterID>
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reachability_testing::next_random(AbstractRouter* router, const time_point_t& now, bool requeue)
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{
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if (next_general_test > now)
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return std::nullopt;
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next_general_test = now
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+ std::chrono::duration_cast<time_point_t::duration>(
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fseconds(TESTING_INTERVAL(detail::rng())));
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// Pull the next element off the queue, but skip ourself, any that are no longer registered, and
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// any that are currently known to be failing (those are queued for testing separately).
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RouterID my_pk{router->pubkey()};
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while (!testing_queue.empty())
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{
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auto& pk = testing_queue.back();
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std::optional<RouterID> sn;
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if (pk != my_pk && !failing.count(pk))
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sn = pk;
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testing_queue.pop_back();
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if (sn)
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return sn;
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}
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if (!requeue)
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return std::nullopt;
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// FIXME: when a *new* node comes online we need to inject it into a random position in the SN
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// list with probability (L/N) [L = current list size, N = potential list size]
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//
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// (FIXME: put this FIXME in a better place ;-) )
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// We exhausted the queue so repopulate it and try again
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testing_queue.clear();
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const auto all = router->GetRouterWhitelist();
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testing_queue.insert(testing_queue.begin(), all.begin(), all.end());
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std::shuffle(testing_queue.begin(), testing_queue.end(), detail::rng());
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// Recurse with the rebuild list, but don't let it try rebuilding again
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return next_random(router, now, false);
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}
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std::vector<std::pair<RouterID, int>>
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reachability_testing::get_failing(AbstractRouter*, const time_point_t& now)
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{
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// Our failing_queue puts the oldest retest times at the top, so pop them off into our result
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// until the top node should be retested sometime in the future
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std::vector<std::pair<RouterID, int>> result;
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while (result.size() < MAX_RETESTS_PER_TICK && !failing_queue.empty())
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{
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auto& [pk, retest_time, failures] = failing_queue.top();
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if (retest_time > now)
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break;
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result.emplace_back(pk, failures);
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failing.erase(pk);
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failing_queue.pop();
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}
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return result;
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}
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void
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reachability_testing::add_failing_node(const RouterID& pk, int previous_failures)
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{
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using namespace std::chrono;
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if (previous_failures < 0)
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previous_failures = 0;
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auto next_test_in = duration_cast<time_point_t::duration>(
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previous_failures * TESTING_BACKOFF + fseconds{TESTING_INTERVAL(detail::rng())});
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if (next_test_in > TESTING_BACKOFF_MAX)
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next_test_in = TESTING_BACKOFF_MAX;
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failing_queue.emplace(pk, steady_clock::now() + next_test_in, previous_failures + 1);
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}
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} // namespace llarp::consensus
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@ -0,0 +1,144 @@
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#pragma once
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#include <chrono>
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#include <queue>
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#include <random>
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#include <unordered_map>
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#include <unordered_set>
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#include <vector>
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#include <llarp/util/time.hpp>
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#include <llarp/router_id.hpp>
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namespace llarp
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{
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struct AbstractRouter;
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}
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namespace llarp::consensus
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{
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namespace detail
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{
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using clock_t = std::chrono::steady_clock;
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using time_point_t = std::chrono::time_point<clock_t>;
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// Returns std::greater on the std::get<N>(v)th element value.
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template <typename T, size_t N>
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struct nth_greater
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{
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constexpr bool
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operator()(const T& lhs, const T& rhs) const
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{
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return std::greater<std::tuple_element_t<N, T>>{}(std::get<N>(lhs), std::get<N>(rhs));
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}
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};
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struct incoming_test_state
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{
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time_point_t last_test{};
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time_point_t last_whine{};
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bool was_failing = false;
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};
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} // namespace detail
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using time_point_t = detail::time_point_t;
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using clock_t = detail::clock_t;
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class reachability_testing
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{
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public:
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// How often we tick the timer to check whether we need to do any tests.
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inline static constexpr auto TESTING_TIMER_INTERVAL = 50ms;
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// Distribution for the seconds between node tests: we throw in some randomness to avoid
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// potential clustering of tests. (Note that there is some granularity here as the test timer
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// only runs every TESTING_TIMER_INTERVAL).
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inline static thread_local std::normal_distribution<float> TESTING_INTERVAL{10.0, 3.0};
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// The linear backoff after each consecutive test failure before we re-test. Specifically we
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// schedule the next re-test for (TESTING_BACKOFF*previous_failures) + TESTING_INTERVAL(rng).
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inline static constexpr auto TESTING_BACKOFF = 10s;
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// The upper bound for the re-test interval.
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inline static constexpr auto TESTING_BACKOFF_MAX = 2min;
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// The maximum number of nodes that we will re-test at once (i.e. per TESTING_TIMING_INTERVAL);
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// mainly intended to throttle ourselves if, for instance, our own connectivity loss makes us
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// accumulate tons of nodes to test all at once. (Despite the random intervals, this can happen
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// if we also get decommissioned during which we can't test at all but still have lots of
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// failing nodes we want to test right away when we get recommissioned).
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inline static constexpr int MAX_RETESTS_PER_TICK = 4;
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// Maximum time without a ping before we start whining about it.
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//
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// We have a probability of about 0.368* of *not* getting pinged within a ping interval (10s),
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// and so the probability of not getting a ping for 2 minutes (i.e. 12 test spans) just because
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// we haven't been selected is extremely small (0.0000061). It also coincides nicely with
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// blockchain time (i.e. two minutes) and our max testing backoff.
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//
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// * = approx value of ((n-1)/n)^n for non-tiny values of n
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inline static constexpr auto MAX_TIME_WITHOUT_PING = 2min;
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// How often we whine in the logs about being unreachable
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inline static constexpr auto WHINING_INTERVAL = 2min;
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private:
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// Queue of pubkeys of service nodes to test; we pop off the back of this until the queue
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// empties then we refill it with a shuffled list of all pubkeys then pull off of it until it is
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// empty again, etc.
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std::vector<RouterID> testing_queue;
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// The next time for a general test
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time_point_t next_general_test = time_point_t::min();
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// When we started, so that we know not to hold off on whining about no pings for a while.
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const time_point_t startup = clock_t::now();
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// Pubkeys, next test times, and sequential failure counts of service nodes that are currently
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// in "failed" status along with the last time they failed; we retest them first after 10s then
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// back off linearly by an additional 10s up to a max testing interval of 2m30s, until we get a
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// successful response.
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using FailingPK = std::tuple<RouterID, time_point_t, int>;
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std::priority_queue<FailingPK, std::vector<FailingPK>, detail::nth_greater<FailingPK, 1>>
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failing_queue;
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std::unordered_set<RouterID> failing;
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// Track the last time *this node* was tested by other network nodes; used to detect and warn
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// about possible network issues.
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detail::incoming_test_state last;
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public:
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// If it is time to perform another random test, this returns the next node to test from the
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// testing queue and returns it, also updating the timer for the next test. If it is not yet
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// time, or if the queue is empty and cannot current be replenished, returns std::nullopt. If
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// the queue empties then this builds a new one by shuffling current public keys in the swarm's
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// "all nodes" then starts using the new queue for this an subsequent calls.
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//
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// `requeue` is mainly for internal use: if false it avoids rebuilding the queue if we run
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// out (and instead just return nullopt).
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std::optional<RouterID>
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next_random(
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AbstractRouter* router, const time_point_t& now = clock_t::now(), bool requeue = true);
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// Removes and returns up to MAX_RETESTS_PER_TICK nodes that are due to be tested (i.e.
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// next-testing-time <= now). Returns [snrecord, #previous-failures] for each.
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std::vector<std::pair<RouterID, int>>
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get_failing(AbstractRouter* router, const time_point_t& now = clock_t::now());
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// Adds a bad node pubkey to the failing list, to be re-tested soon (with a backoff depending on
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// `failures`; see TESTING_BACKOFF). `previous_failures` should be the number of previous
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// failures *before* this one, i.e. 0 for a random general test; or the failure count returned
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// by `get_failing` for repeated failures.
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void
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add_failing_node(const RouterID& pk, int previous_failures = 0);
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// Called when this router receives an incomming session
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void
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incoming_ping(const time_point_t& now = clock_t::now());
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// Check whether we received incoming pings recently
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void
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check_incoming_tests(const time_point_t& now = clock_t::now());
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};
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} // namespace llarp::consensus
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