PeerImp.h

#pragma once
 
#include <xrpld/app/consensus/RCLCxPeerPos.h>
#include <xrpld/app/ledger/detail/LedgerReplayMsgHandler.h>
#include <xrpld/overlay/Squelch.h>
#include <xrpld/overlay/detail/OverlayImpl.h>
#include <xrpld/overlay/detail/ProtocolVersion.h>
#include <xrpld/peerfinder/PeerfinderManager.h>
 
#include <xrpl/basics/UnorderedContainers.h>
#include <xrpl/beast/utility/WrappedSink.h>
#include <xrpl/core/HashRouter.h>
#include <xrpl/protocol/Protocol.h>
#include <xrpl/protocol/STTx.h>
#include <xrpl/protocol/STValidation.h>
#include <xrpl/resource/Fees.h>
 
#include <boost/circular_buffer.hpp>
#include <boost/endian/conversion.hpp>
#include <boost/thread/shared_mutex.hpp>
 
#include <atomic>
#include <cstdint>
#include <optional>
#include <queue>
#include <utility>
 
namespace xrpl {
 
struct ValidatorBlobInfo;
class SHAMap;
 
class PeerImp : public Peer, public std::enable_shared_from_this<PeerImp>, public OverlayImpl::Child
{
public:
    enum class Tracking { Diverged, Unknown, Converged };
 
private:
    using clock_type = std::chrono::steady_clock;
    using error_code = boost::system::error_code;
    using socket_type = boost::asio::ip::tcp::socket;
    using middle_type = boost::beast::tcp_stream;
    using stream_type = boost::beast::ssl_stream<middle_type>;
    using address_type = boost::asio::ip::address;
    using endpoint_type = boost::asio::ip::tcp::endpoint;
    using waitable_timer = boost::asio::basic_waitable_timer<std::chrono::steady_clock>;
    using Compressed = compression::Compressed;
 
    Application& app_;
    id_t const id_;
    std::string fingerprint_;
    std::string prefix_;
    beast::WrappedSink sink_;
    beast::WrappedSink pSink_;
    beast::Journal const journal_;
    beast::Journal const pJournal_;
    std::unique_ptr<stream_type> streamPtr_;
    socket_type& socket_;
    stream_type& stream_;
    boost::asio::strand<boost::asio::executor> strand_;
    waitable_timer timer_;
 
    // Updated at each stage of the connection process to reflect
    // the current conditions as closely as possible.
    beast::IP::Endpoint const remoteAddress_;
 
    // These are up here to prevent warnings about order of initializations
    //
    OverlayImpl& overlay_;
    bool const inbound_;
 
    // Protocol version to use for this link
    ProtocolVersion protocol_;
 
    std::atomic<Tracking> tracking_;
    clock_type::time_point trackingTime_;
    bool detaching_ = false;
    // Node public key of peer.
    PublicKey const publicKey_;
    std::string name_;
    std::shared_mutex mutable nameMutex_;
 
    // The indices of the smallest and largest ledgers this peer has available
    //
    LedgerIndex minLedger_ = 0;
    LedgerIndex maxLedger_ = 0;
    uint256 closedLedgerHash_;
    uint256 previousLedgerHash_;
 
    boost::circular_buffer<uint256> recentLedgers_{128};
    boost::circular_buffer<uint256> recentTxSets_{128};
 
    std::optional<std::chrono::milliseconds> latency_;
    std::optional<std::uint32_t> lastPingSeq_;
    clock_type::time_point lastPingTime_;
    clock_type::time_point const creationTime_;
 
    reduce_relay::Squelch<UptimeClock> squelch_;
 
    // Notes on thread locking:
    //
    // During an audit it was noted that some member variables that looked
    // like they need thread protection were not receiving it.  And, indeed,
    // that was correct.  But the multi-phase initialization of PeerImp
    // makes such an audit difficult.  A further audit suggests that the
    // locking is now protecting variables that don't need it.  We're
    // leaving that locking in place (for now) as a form of future proofing.
    //
    // Here are the variables that appear to need locking currently:
    //
    // o closedLedgerHash_
    // o previousLedgerHash_
    // o minLedger_
    // o maxLedger_
    // o recentLedgers_
    // o recentTxSets_
    // o trackingTime_
    // o latency_
    //
    // The following variables are being protected preemptively:
    //
    // o name_
    // o lastStatus_
    //
    // June 2019
 
    struct ChargeWithContext
    {
        Resource::Charge fee = Resource::kFeeTrivialPeer;
        std::string context{};  // NOLINT(readability-redundant-member-init)
 
        void
        update(Resource::Charge f, std::string const& add)
        {
            XRPL_ASSERT(f >= fee, "xrpl::PeerImp::ChargeWithContext::update : fee increases");
            fee = f;
            if (!context.empty())
            {
                context += " ";
            }
            context += add;
        }
    };
 
    std::mutex mutable recentLock_;
    protocol::TMStatusChange lastStatus_;
    Resource::Consumer usage_;
    ChargeWithContext fee_;
 
    // One-shot guard so concurrent JobQueue workers cannot double-count
    // the per-connection peer-disconnect-by-charge metric (and cannot
    // post duplicate fail() calls) when several queued requests cross
    // kDropThreshold before the first fail() lands on the strand.
    std::atomic<bool> chargeDisconnectFired_{false};
    std::shared_ptr<PeerFinder::Slot> const slot_;
    boost::beast::multi_buffer readBuffer_;
    http_request_type request_;
    http_response_type response_;
    boost::beast::http::fields const& headers_;
    std::queue<std::shared_ptr<Message>> sendQueue_;
    bool gracefulClose_ = false;
    int largeSendq_ = 0;
    std::unique_ptr<LoadEvent> loadEvent_;
    // The highest sequence of each PublisherList that has
    // been sent to or received from this peer.
    hash_map<PublicKey, std::size_t> publisherListSequences_;
 
    Compressed compressionEnabled_ = Compressed::Off;
 
    // Queue of transactions' hashes that have not been
    // relayed. The hashes are sent once a second to a peer
    // and the peer requests missing transactions from the node.
    hash_set<uint256> txQueue_;
    // true if tx reduce-relay feature is enabled on the peer.
    bool txReduceRelayEnabled_ = false;
 
    bool ledgerReplayEnabled_ = false;
    LedgerReplayMsgHandler ledgerReplayMsgHandler_;
 
    friend class OverlayImpl;
 
    class Metrics
    {
    public:
        Metrics() = default;
        Metrics(Metrics const&) = delete;
        Metrics&
        operator=(Metrics const&) = delete;
        Metrics(Metrics&&) = delete;
        Metrics&
        operator=(Metrics&&) = delete;
 
        void
        addMessage(std::uint64_t bytes);
        std::uint64_t
        averageBytes() const;
        std::uint64_t
        totalBytes() const;
 
    private:
        std::shared_mutex mutable mutex_;
        boost::circular_buffer<std::uint64_t> rollingAvg_{30, 0ull};
        clock_type::time_point intervalStart_{clock_type::now()};
        std::uint64_t totalBytes_{0};
        std::uint64_t accumBytes_{0};
        std::uint64_t rollingAvgBytes_{0};
    };
 
    struct
    {
        Metrics sent;
        Metrics recv;
    } metrics_;
 
public:
    PeerImp(PeerImp const&) = delete;
    PeerImp&
    operator=(PeerImp const&) = delete;

    PeerImp(
        Application& app,
        id_t id,
        std::shared_ptr<PeerFinder::Slot> const& slot,
        http_request_type&& request,
        PublicKey const& publicKey,
        ProtocolVersion protocol,
        Resource::Consumer consumer,
        std::unique_ptr<stream_type>&& streamPtr,
        OverlayImpl& overlay);

    // VFALCO legacyPublicKey should be implied by the Slot
    template <class Buffers>
    PeerImp(
        Application& app,
        std::unique_ptr<stream_type>&& streamPtr,
        Buffers const& buffers,
        std::shared_ptr<PeerFinder::Slot>&& slot,
        http_response_type&& response,
        Resource::Consumer usage,
        PublicKey const& publicKey,
        ProtocolVersion protocol,
        id_t id,
        OverlayImpl& overlay);
 
    ~PeerImp() override;
 
    beast::Journal const&
    pJournal() const
    {
        return pJournal_;
    }
 
    std::shared_ptr<PeerFinder::Slot> const&
    slot()
    {
        return slot_;
    }
 
    // Work-around for calling shared_from_this in constructors
    virtual void
    run();
 
    // Called when Overlay gets a stop request.
    void
    stop() override;
 
    //
    // Network
    //
 
    void
    send(std::shared_ptr<Message> const& m) override;

    void
    sendTxQueue() override;

    void
    addTxQueue(uint256 const& hash) override;

    void
    removeTxQueue(uint256 const& hash) override;

    template <
        class FwdIt,
        class = std::enable_if_t<
            std::is_same_v<typename std::iterator_traits<FwdIt>::value_type, PeerFinder::Endpoint>>>
    void
    sendEndpoints(FwdIt first, FwdIt last);
 
    beast::IP::Endpoint
    getRemoteAddress() const override
    {
        return remoteAddress_;
    }
 
    void
    charge(Resource::Charge const& fee, std::string const& context) override;
 
    //
    // Identity
    //
 
    Peer::id_t
    id() const override
    {
        return id_;
    }

    bool
    crawl() const;
 
    bool
    cluster() const override;

    void
    checkTracking(std::uint32_t validationSeq);
 
    void
    checkTracking(std::uint32_t seq1, std::uint32_t seq2);
 
    PublicKey const&
    getNodePublic() const override
    {
        return publicKey_;
    }

    std::string
    getVersion() const;
 
    // Return the connection elapsed time.
    clock_type::duration
    uptime() const
    {
        return clock_type::now() - creationTime_;
    }
 
    json::Value
    json() override;
 
    bool
    supportsFeature(ProtocolFeature f) const override;
 
    std::optional<std::size_t>
    publisherListSequence(PublicKey const& pubKey) const override
    {
        std::scoped_lock const sl(recentLock_);
 
        auto iter = publisherListSequences_.find(pubKey);
        if (iter != publisherListSequences_.end())
            return iter->second;
        return {};
    }
 
    void
    setPublisherListSequence(PublicKey const& pubKey, std::size_t const seq) override
    {
        std::scoped_lock const sl(recentLock_);
 
        publisherListSequences_[pubKey] = seq;
    }
 
    //
    // Ledger
    //
 
    uint256 const&
    getClosedLedgerHash() const override
    {
        return closedLedgerHash_;
    }
 
    bool
    hasLedger(uint256 const& hash, std::uint32_t seq) const override;
 
    void
    ledgerRange(std::uint32_t& minSeq, std::uint32_t& maxSeq) const override;
 
    bool
    hasTxSet(uint256 const& hash) const override;
 
    void
    cycleStatus() override;
 
    bool
    hasRange(std::uint32_t uMin, std::uint32_t uMax) override;
 
    // Called to determine our priority for querying
    int
    getScore(bool haveItem) const override;
 
    bool
    isHighLatency() const override;
 
    void
    fail(std::string const& reason);
 
    bool
    compressionEnabled() const override
    {
        return compressionEnabled_ == Compressed::On;
    }
 
    bool
    txReduceRelayEnabled() const override
    {
        return txReduceRelayEnabled_;
    }
 
private:
    void
    close();
 
    void
    fail(std::string const& name, error_code ec);
 
    void
    gracefulClose();
 
    void
    setTimer();
 
    void
    cancelTimer() noexcept;
 
    static std::string
    makePrefix(std::string const& fingerprint);
 
    // Called when the timer wait completes
    void
    onTimer(boost::system::error_code const& ec);
 
    // Called when SSL shutdown completes
    void
    onShutdown(error_code ec);
 
    void
    doAccept();
 
    std::string
    name() const;
 
    std::string
    domain() const;
 
    //
    // protocol message loop
    //
 
    // Starts the protocol message loop
    void
    doProtocolStart();
 
    // Called when protocol message bytes are received
    void
    onReadMessage(error_code ec, std::size_t bytesTransferred);
 
    // Called when protocol messages bytes are sent
    void
    onWriteMessage(error_code ec, std::size_t bytesTransferred);

    void
    handleTransaction(
        std::shared_ptr<protocol::TMTransaction> const& m,
        bool eraseTxQueue,
        bool batch);

    void
    handleHaveTransactions(std::shared_ptr<protocol::TMHaveTransactions> const& m);
 
    std::string const&
    fingerprint() const override
    {
        return fingerprint_;
    }
 
    std::string const&
    prefix() const
    {
        return prefix_;
    }
 
public:
    //--------------------------------------------------------------------------
    //
    // ProtocolStream
    //
    //--------------------------------------------------------------------------
 
    void
    onMessageUnknown(std::uint16_t type);
 
    void
    onMessageBegin(
        std::uint16_t type,
        std::shared_ptr<::google::protobuf::Message> const& m,
        std::size_t size,
        std::size_t uncompressedSize,
        bool isCompressed);
 
    void
    onMessageEnd(std::uint16_t type, std::shared_ptr<::google::protobuf::Message> const& m);
 
    void
    onMessage(std::shared_ptr<protocol::TMManifests> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMPing> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMCluster> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMEndpoints> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMTransaction> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMGetLedger> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMLedgerData> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMProposeSet> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMStatusChange> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMHaveTransactionSet> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMValidatorList> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMValidatorListCollection> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMValidation> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMGetObjectByHash> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMHaveTransactions> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMTransactions> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMSquelch> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMProofPathRequest> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMProofPathResponse> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMReplayDeltaRequest> const& m);
    void
    onMessage(std::shared_ptr<protocol::TMReplayDeltaResponse> const& m);
 
private:
    //--------------------------------------------------------------------------
    // lockedRecentLock is passed as a reminder to callers that recentLock_
    // must be locked.
    void
    addLedger(uint256 const& hash, std::scoped_lock<std::mutex> const& lockedRecentLock);
 
    void
    doFetchPack(std::shared_ptr<protocol::TMGetObjectByHash> const& packet);
 
    void
    onValidatorListMessage(
        std::string const& messageType,
        std::string const& manifest,
        std::uint32_t version,
        std::vector<ValidatorBlobInfo> const& blobs);

    void
    doTransactions(std::shared_ptr<protocol::TMGetObjectByHash> const& packet);
 
    void
    checkTransaction(
        HashRouterFlags flags,
        bool checkSignature,
        std::shared_ptr<STTx const> const& stx,
        bool batch);
 
    void
    checkPropose(
        bool isTrusted,
        std::shared_ptr<protocol::TMProposeSet> const& packet,
        RCLCxPeerPos peerPos);
 
    void
    checkValidation(
        std::shared_ptr<STValidation> const& val,
        uint256 const& key,
        std::shared_ptr<protocol::TMValidation> const& packet);
 
    void
    sendLedgerBase(std::shared_ptr<Ledger const> const& ledger, protocol::TMLedgerData& ledgerData);
 
    std::shared_ptr<Ledger const>
    getLedger(std::shared_ptr<protocol::TMGetLedger> const& m);
 
    std::shared_ptr<SHAMap const>
    getTxSet(std::shared_ptr<protocol::TMGetLedger> const& m) const;
 
    void
    processLedgerRequest(std::shared_ptr<protocol::TMGetLedger> const& m);
 
protected:
    // Kept `protected` so test subclasses (see
    // TMGetObjectByHash_test) can drive the
    // synchronous processor and the differential-pricing helper without
    // routing through the JobQueue or going through `friend` plumbing.
    // Production callers reach these members only via
    // `onMessage(TMGetObjectByHash)` → JobQueue → `processGetObjectByHash`.

    void
    processGetObjectByHash(std::shared_ptr<protocol::TMGetObjectByHash> const& m);

    static Resource::Charge
    computeGetObjectByHashFee(int const requested, int const found);

    Resource::Charge
    currentFeeCharge() const
    {
        return fee_.fee;
    }
};
 
//------------------------------------------------------------------------------
 
template <class Buffers>
PeerImp::PeerImp(
    Application& app,
    std::unique_ptr<stream_type>&& streamPtr,
    Buffers const& buffers,
    std::shared_ptr<PeerFinder::Slot>&& slot,
    http_response_type&& response,
    Resource::Consumer usage,
    PublicKey const& publicKey,
    ProtocolVersion protocol,
    id_t id,
    OverlayImpl& overlay)
    : Child(overlay)
    , app_(app)
    , id_(id)
    , fingerprint_(getFingerprint(slot->remoteEndpoint(), publicKey, to_string(id_)))
    , prefix_(makePrefix(fingerprint_))
    , sink_(app_.getJournal("Peer"), prefix_)
    , pSink_(app_.getJournal("Protocol"), prefix_)
    , journal_(sink_)
    , pJournal_(pSink_)
    , streamPtr_(std::move(streamPtr))
    , socket_(streamPtr_->next_layer().socket())
    , stream_(*streamPtr_)
    , strand_(boost::asio::make_strand(socket_.get_executor()))
    , timer_(waitable_timer{socket_.get_executor()})
    , remoteAddress_(slot->remoteEndpoint())
    , overlay_(overlay)
    , inbound_(false)
    , protocol_(std::move(protocol))
    , tracking_(Tracking::Unknown)
    , trackingTime_(clock_type::now())
    , publicKey_(publicKey)
    , lastPingTime_(clock_type::now())
    , creationTime_(clock_type::now())
    , squelch_(app_.getJournal("Squelch"))
    , usage_(usage)
    , fee_{.fee = Resource::kFeeTrivialPeer}
    , slot_(std::move(slot))
    , response_(std::move(response))
    , headers_(response_)
    , compressionEnabled_(
          peerFeatureEnabled(headers_, kFeatureCompr, "lz4", app_.config().compression)
              ? Compressed::On
              : Compressed::Off)
    , txReduceRelayEnabled_(
          peerFeatureEnabled(headers_, kFeatureTxrr, app_.config().txReduceRelayEnable))
    , ledgerReplayEnabled_(
          peerFeatureEnabled(headers_, kFeatureLedgerReplay, app_.config().ledgerReplay))
    , ledgerReplayMsgHandler_(app, app.getLedgerReplayer())
{
    readBuffer_.commit(
        boost::asio::buffer_copy(readBuffer_.prepare(boost::asio::buffer_size(buffers)), buffers));
    JLOG(journal_.info())
        << "compression enabled " << (compressionEnabled_ == Compressed::On)
        << " vp reduce-relay base squelch enabled "
        << peerFeatureEnabled(headers_, kFeatureVprr, app_.config().vpReduceRelayBaseSquelchEnable)
        << " tx reduce-relay enabled " << txReduceRelayEnabled_ << " on " << remoteAddress_ << " "
        << id_;
}
 
template <class FwdIt, class>
void
PeerImp::sendEndpoints(FwdIt first, FwdIt last)
{
    protocol::TMEndpoints tm;
 
    while (first != last)
    {
        auto& tme2(*tm.add_endpoints_v2());
        tme2.set_endpoint(first->address.toString());
        tme2.set_hops(first->hops);
        first++;
    }
    tm.set_version(2);
 
    send(std::make_shared<Message>(tm, protocol::mtENDPOINTS));
}
 
}  // namespace xrpl