InboundLedgers.cpp

//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2012, 2013 Ripple Labs Inc.
 
    Permission to use, copy, modify, and/or distribute this software for any
    purpose  with  or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.
 
    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
 
#include <xrpld/app/ledger/InboundLedgers.h>
#include <xrpld/app/ledger/LedgerMaster.h>
#include <xrpld/app/main/Application.h>
#include <xrpld/app/misc/NetworkOPs.h>
#include <xrpld/core/JobQueue.h>
#include <xrpld/perflog/PerfLog.h>
#include <xrpl/basics/CanProcess.h>
#include <xrpl/basics/DecayingSample.h>
#include <xrpl/basics/Log.h>
#include <xrpl/beast/container/aged_map.h>
#include <xrpl/beast/core/LexicalCast.h>
#include <xrpl/protocol/jss.h>
 
#include <exception>
#include <memory>
#include <mutex>
#include <vector>
 
namespace ripple {
 
class InboundLedgersImp : public InboundLedgers
{
private:
    Application& app_;
    std::mutex fetchRateMutex_;
    // measures ledgers per second, constants are important
    DecayWindow<30, clock_type> fetchRate_;
    beast::Journal const j_;
 
public:
    // How long before we try again to acquire the same ledger
    static constexpr std::chrono::minutes const kReacquireInterval{5};
 
    InboundLedgersImp(
        Application& app,
        clock_type& clock,
        beast::insight::Collector::ptr const& collector,
        std::unique_ptr<PeerSetBuilder> peerSetBuilder)
        : app_(app)
        , fetchRate_(clock.now())
        , j_(app.journal("InboundLedger"))
        , m_clock(clock)
        , mRecentFailures(clock)
        , mCounter(collector->make_counter("ledger_fetches"))
        , mPeerSetBuilder(std::move(peerSetBuilder))
    {
    }
 
    std::shared_ptr<Ledger const>
    acquire(
        uint256 const& hash,
        std::uint32_t seq,
        InboundLedger::Reason reason) override
    {
        auto doAcquire = [&, seq, reason]() -> std::shared_ptr<Ledger const> {
            XRPL_ASSERT(
                hash.isNonZero(),
                "ripple::InboundLedgersImp::acquire::doAcquire : nonzero hash");
 
            bool const needNetworkLedger = app_.getOPs().isNeedNetworkLedger();
            bool const shouldAcquire = [&]() {
                if (!needNetworkLedger)
                    return true;
                if (reason == InboundLedger::Reason::GENERIC)
                    return true;
                if (reason == InboundLedger::Reason::CONSENSUS)
                    return true;
                return false;
            }();
 
            std::stringstream ss;
            ss << "InboundLedger::acquire: "
               << "Request: " << to_string(hash) << ", " << seq
               << " NeedNetworkLedger: " << (needNetworkLedger ? "yes" : "no")
               << " Reason: " << to_string(reason)
               << " Should acquire: " << (shouldAcquire ? "true." : "false.");
 
            /*  Acquiring ledgers is somewhat expensive. It requires lots of
             *  computation and network communication. Avoid it when it's not
             *  appropriate. Every validation from a peer for a ledger that
             *  we do not have locally results in a call to this function: even
             *  if we are moments away from validating the same ledger.
             */
            bool const shouldBroadcast = [&]() {
                // If the node is not in "full" state, it needs to sync to
                // the network, and doesn't have the necessary tx's and
                // ledger entries to build the ledger.
                bool const isFull = app_.getOPs().isFull();
                // If everything else is ok, don't try to acquire the ledger
                // if the requested seq is in the near future relative to
                // the validated ledger. If the requested ledger is between
                // 1 and 19 inclusive ledgers ahead of the valid ledger this
                // node has not built it yet, but it's possible/likely it
                // has the tx's necessary to build it and get caught up.
                // Plus it might not become validated. On the other hand, if
                // it's more than 20 in the future, this node should request
                // it so that it can jump ahead and get caught up.
                LedgerIndex const validSeq =
                    app_.getLedgerMaster().getValidLedgerIndex();
                constexpr std::size_t lagLeeway = 20;
                bool const nearFuture =
                    (seq > validSeq) && (seq < validSeq + lagLeeway);
                // If everything else is ok, don't try to acquire the ledger
                // if the request is related to consensus. (Note that
                // consensus calls usually pass a seq of 0, so nearFuture
                // will be false other than on a brand new network.)
                bool const consensus =
                    reason == InboundLedger::Reason::CONSENSUS;
                ss << " Evaluating whether to broadcast requests to peers"
                   << ". full: " << (isFull ? "true" : "false")
                   << ". ledger sequence " << seq
                   << ". Valid sequence: " << validSeq
                   << ". Lag leeway: " << lagLeeway
                   << ". request for near future ledger: "
                   << (nearFuture ? "true" : "false")
                   << ". Consensus: " << (consensus ? "true" : "false");
 
                // If the node is not synced, send requests.
                if (!isFull)
                    return true;
                // If the ledger is in the near future, do NOT send requests.
                // This node is probably about to build it.
                if (nearFuture)
                    return false;
                // If the request is because of consensus, do NOT send requests.
                // This node is probably about to build it.
                if (consensus)
                    return false;
                return true;
            }();
            ss << ". Would broadcast to peers? "
               << (shouldBroadcast ? "true." : "false.");
 
            if (!shouldAcquire)
            {
                JLOG(j_.debug()) << "Abort(rule): " << ss.str();
                return {};
            }
 
            bool isNew = true;
            std::shared_ptr<InboundLedger> inbound;
            {
                ScopedLockType sl(mLock);
                if (stopping_)
                {
                    JLOG(j_.debug()) << "Abort(stopping): " << ss.str();
                    return {};
                }
 
                auto it = mLedgers.find(hash);
                if (it != mLedgers.end())
                {
                    isNew = false;
                    inbound = it->second;
                }
                else
                {
                    inbound = std::make_shared<InboundLedger>(
                        app_,
                        hash,
                        seq,
                        reason,
                        std::ref(m_clock),
                        mPeerSetBuilder->build());
                    mLedgers.emplace(hash, inbound);
                    inbound->init(sl);
                    ++mCounter;
                }
            }
            ss << " IsNew: " << (isNew ? "true" : "false");
 
            if (inbound->isFailed())
            {
                JLOG(j_.debug()) << "Abort(failed): " << ss.str();
                return {};
            }
 
            if (!isNew)
                inbound->update(seq);
 
            if (!inbound->isComplete())
            {
                JLOG(j_.debug()) << "InProgress: " << ss.str();
                return {};
            }
 
            JLOG(j_.debug()) << "Complete: " << ss.str();
            return inbound->getLedger();
        };
        using namespace std::chrono_literals;
        return perf::measureDurationAndLog(
            doAcquire, "InboundLedgersImp::acquire", 500ms, j_);
    }
 
    void
    acquireAsync(
        uint256 const& hash,
        std::uint32_t seq,
        InboundLedger::Reason reason) override
    {
        if (CanProcess const check{acquiresMutex_, pendingAcquires_, hash})
        {
            try
            {
                acquire(hash, seq, reason);
            }
            catch (std::exception const& e)
            {
                JLOG(j_.warn())
                    << "Exception thrown for acquiring new inbound ledger "
                    << hash << ": " << e.what();
            }
            catch (...)
            {
                JLOG(j_.warn()) << "Unknown exception thrown for acquiring new "
                                   "inbound ledger "
                                << hash;
            }
        }
    }
 
    std::shared_ptr<InboundLedger>
    find(uint256 const& hash) override
    {
        XRPL_ASSERT(
            hash.isNonZero(),
            "ripple::InboundLedgersImp::find : nonzero input");
 
        std::shared_ptr<InboundLedger> ret;
 
        {
            ScopedLockType sl(mLock);
 
            auto it = mLedgers.find(hash);
            if (it != mLedgers.end())
            {
                ret = it->second;
            }
        }
 
        return ret;
    }
 
    /*
    This gets called when
        "We got some data from an inbound ledger"
 
    inboundLedgerTrigger:
      "What do we do with this partial data?"
      Figures out what to do with the responses to our requests for information.
 
    */
    // means "We got some data from an inbound ledger"
 
    // VFALCO TODO Remove the dependency on the Peer object.
    bool
    gotLedgerData(
        LedgerHash const& hash,
        std::shared_ptr<Peer> peer,
        std::shared_ptr<protocol::TMLedgerData> packet) override
    {
        if (auto ledger = find(hash))
        {
            JLOG(j_.trace()) << "Got data (" << packet->nodes().size()
                             << ") for acquiring ledger: " << hash;
 
            // Stash the data for later processing and see if we need to
            // dispatch
            if (ledger->gotData(std::weak_ptr<Peer>(peer), packet))
                app_.getJobQueue().addJob(
                    jtLEDGER_DATA, "processLedgerData", [ledger]() {
                        ledger->runData();
                    });
 
            return true;
        }
 
        JLOG(j_.trace()) << "Got data for ledger " << hash
                         << " which we're no longer acquiring";
 
        // If it's state node data, stash it because it still might be
        // useful.
        if (packet->type() == protocol::liAS_NODE)
        {
            app_.getJobQueue().addJob(
                jtLEDGER_DATA, "gotStaleData", [this, packet]() {
                    gotStaleData(packet);
                });
        }
 
        return false;
    }
 
    void
    logFailure(uint256 const& h, std::uint32_t seq) override
    {
        ScopedLockType sl(mLock);
 
        mRecentFailures.emplace(h, seq);
    }
 
    bool
    isFailure(uint256 const& h) override
    {
        ScopedLockType sl(mLock);
 
        beast::expire(mRecentFailures, kReacquireInterval);
        return mRecentFailures.find(h) != mRecentFailures.end();
    }
 
    void
    gotStaleData(std::shared_ptr<protocol::TMLedgerData> packet_ptr) override
    {
        Serializer s;
        try
        {
            for (int i = 0; i < packet_ptr->nodes().size(); ++i)
            {
                auto const& node = packet_ptr->nodes(i);
 
                if (!node.has_nodeid() || !node.has_nodedata())
                    return;
 
                auto newNode =
                    SHAMapTreeNode::makeFromWire(makeSlice(node.nodedata()));
 
                if (!newNode)
                    return;
 
                s.erase();
                newNode->serializeWithPrefix(s);
 
                app_.getLedgerMaster().addFetchPack(
                    newNode->getHash().as_uint256(),
                    std::make_shared<Blob>(s.begin(), s.end()));
            }
        }
        catch (std::exception const&)
        {
        }
    }
 
    void
    clearFailures() override
    {
        ScopedLockType sl(mLock);
 
        mRecentFailures.clear();
        mLedgers.clear();
    }
 
    std::size_t
    fetchRate() override
    {
        std::lock_guard lock(fetchRateMutex_);
        return 60 * fetchRate_.value(m_clock.now());
    }
 
    // Should only be called with an inboundledger that has
    // a reason of history
    void
    onLedgerFetched() override
    {
        std::lock_guard lock(fetchRateMutex_);
        fetchRate_.add(1, m_clock.now());
    }
 
    Json::Value
    getInfo() override
    {
        Json::Value ret(Json::objectValue);
 
        std::vector<std::pair<uint256, std::shared_ptr<InboundLedger>>> acqs;
 
        {
            ScopedLockType sl(mLock);
 
            acqs.reserve(mLedgers.size());
            for (auto const& it : mLedgers)
            {
                XRPL_ASSERT(
                    it.second,
                    "ripple::InboundLedgersImp::getInfo : non-null ledger");
                acqs.push_back(it);
            }
            for (auto const& it : mRecentFailures)
            {
                if (it.second > 1)
                    ret[std::to_string(it.second)][jss::failed] = true;
                else
                    ret[to_string(it.first)][jss::failed] = true;
            }
        }
 
        for (auto const& it : acqs)
        {
            // getJson is expensive, so call without the lock
            std::uint32_t seq = it.second->getSeq();
            if (seq > 1)
                ret[std::to_string(seq)] = it.second->getJson(0);
            else
                ret[to_string(it.first)] = it.second->getJson(0);
        }
 
        return ret;
    }
 
    void
    gotFetchPack() override
    {
        std::vector<std::shared_ptr<InboundLedger>> acquires;
        {
            ScopedLockType sl(mLock);
 
            acquires.reserve(mLedgers.size());
            for (auto const& it : mLedgers)
            {
                XRPL_ASSERT(
                    it.second,
                    "ripple::InboundLedgersImp::gotFetchPack : non-null "
                    "ledger");
                acquires.push_back(it.second);
            }
        }
 
        for (auto const& acquire : acquires)
        {
            acquire->checkLocal();
        }
    }
 
    void
    sweep() override
    {
        auto const start = m_clock.now();
 
        // Make a list of things to sweep, while holding the lock
        std::vector<MapType::mapped_type> stuffToSweep;
        std::size_t total;
 
        {
            ScopedLockType sl(mLock);
            MapType::iterator it(mLedgers.begin());
            total = mLedgers.size();
 
            stuffToSweep.reserve(total);
 
            while (it != mLedgers.end())
            {
                auto const la = it->second->getLastAction();
 
                if (la > start)
                {
                    it->second->touch();
                    ++it;
                }
                else if ((la + std::chrono::minutes(1)) < start)
                {
                    stuffToSweep.push_back(it->second);
                    // shouldn't cause the actual final delete
                    // since we are holding a reference in the vector.
                    it = mLedgers.erase(it);
                }
                else
                {
                    ++it;
                }
            }
 
            beast::expire(mRecentFailures, kReacquireInterval);
        }
 
        JLOG(j_.debug())
            << "Swept " << stuffToSweep.size() << " out of " << total
            << " inbound ledgers. Duration: "
            << std::chrono::duration_cast<std::chrono::milliseconds>(
                   m_clock.now() - start)
                   .count()
            << "ms";
    }
 
    void
    stop() override
    {
        ScopedLockType lock(mLock);
        stopping_ = true;
        mLedgers.clear();
        mRecentFailures.clear();
    }
 
    std::size_t
    cacheSize() override
    {
        ScopedLockType lock(mLock);
        return mLedgers.size();
    }
 
private:
    clock_type& m_clock;
 
    using ScopedLockType = std::unique_lock<std::recursive_mutex>;
    std::recursive_mutex mLock;
 
    bool stopping_ = false;
    using MapType = hash_map<uint256, std::shared_ptr<InboundLedger>>;
    MapType mLedgers;
 
    beast::aged_map<uint256, std::uint32_t> mRecentFailures;
 
    beast::insight::Counter mCounter;
 
    std::unique_ptr<PeerSetBuilder> mPeerSetBuilder;
 
    std::set<uint256> pendingAcquires_;
    std::mutex acquiresMutex_;
};
 
//------------------------------------------------------------------------------
 
std::unique_ptr<InboundLedgers>
make_InboundLedgers(
    Application& app,
    InboundLedgers::clock_type& clock,
    beast::insight::Collector::ptr const& collector)
{
    return std::make_unique<InboundLedgersImp>(
        app, clock, collector, make_PeerSetBuilder(app));
}
 
}  // namespace ripple