rippled/include/xrpl/overlay/Overlay.h

#ifndef XRPL_OVERLAY_OVERLAY_H_INCLUDED
#define XRPL_OVERLAY_OVERLAY_H_INCLUDED

#include <xrpl/beast/utility/PropertyStream.h>
#include <xrpl/json/json_value.h>
#include <xrpl/overlay/Peer.h>
#include <xrpl/server/Handoff.h>

#include <boost/asio/ip/tcp.hpp>
#include <boost/asio/ssl/context.hpp>
#include <boost/beast/core/tcp_stream.hpp>
#include <boost/beast/ssl/ssl_stream.hpp>

#include <functional>
#include <optional>

namespace boost {
namespace asio {
namespace ssl {
class context;
}
}  // namespace asio
}  // namespace boost

namespace xrpl {

/** Manages the set of connected peers. */
class Overlay : public beast::PropertyStream::Source
{
protected:
    using socket_type = boost::beast::tcp_stream;
    using stream_type = boost::beast::ssl_stream<socket_type>;

    // VFALCO NOTE The requirement of this constructor is an
    //             unfortunate problem with the API for
    //             PropertyStream
    Overlay() : beast::PropertyStream::Source("peers")
    {
    }

public:
    enum class Promote { automatic, never, always };

    struct Setup
    {
        explicit Setup() = default;

        std::shared_ptr<boost::asio::ssl::context> context;
        beast::IP::Address public_ip;
        int ipLimit = 0;
        std::uint32_t crawlOptions = 0;
        std::optional<std::uint32_t> networkID;
        bool vlEnabled = true;
    };

    using PeerSequence = std::vector<std::shared_ptr<Peer>>;

    virtual ~Overlay() = default;

    virtual void
    start()
    {
    }

    virtual void
    stop()
    {
    }

    /** Conditionally accept an incoming HTTP request. */
    virtual Handoff
    onHandoff(
        std::unique_ptr<stream_type>&& bundle,
        http_request_type&& request,
        boost::asio::ip::tcp::endpoint remote_address) = 0;

    /** Establish a peer connection to the specified endpoint.
        The call returns immediately, the connection attempt is
        performed asynchronously.
    */
    virtual void
    connect(beast::IP::Endpoint const& address) = 0;

    /** Returns the maximum number of peers we are configured to allow. */
    virtual int
    limit() = 0;

    /** Returns the number of active peers.
        Active peers are only those peers that have completed the
        handshake and are using the peer protocol.
    */
    virtual std::size_t
    size() const = 0;

    /** Return diagnostics on the status of all peers.
        @deprecated This is superceded by PropertyStream
    */
    virtual Json::Value
    json() = 0;

    /** Returns a sequence representing the current list of peers.
        The snapshot is made at the time of the call.
    */
    virtual PeerSequence
    getActivePeers() const = 0;

    /** Calls the checkTracking function on each peer
        @param index the value to pass to the peer's checkTracking function
    */
    virtual void
    checkTracking(std::uint32_t index) = 0;

    /** Returns the peer with the matching short id, or null. */
    virtual std::shared_ptr<Peer>
    findPeerByShortID(Peer::id_t const& id) const = 0;

    /** Returns the peer with the matching public key, or null. */
    virtual std::shared_ptr<Peer>
    findPeerByPublicKey(PublicKey const& pubKey) = 0;

    /** Broadcast a proposal. */
    virtual void
    broadcast(protocol::TMProposeSet& m) = 0;

    /** Broadcast a validation. */
    virtual void
    broadcast(protocol::TMValidation& m) = 0;

    /** Relay a proposal.
     * @param m the serialized proposal
     * @param uid the id used to identify this proposal
     * @param validator The pubkey of the validator that issued this proposal
     * @return the set of peers which have already sent us this proposal
     */
    virtual std::set<Peer::id_t>
    relay(
        protocol::TMProposeSet& m,
        uint256 const& uid,
        PublicKey const& validator) = 0;

    /** Relay a validation.
     * @param m the serialized validation
     * @param uid the id used to identify this validation
     * @param validator The pubkey of the validator that issued this validation
     * @return the set of peers which have already sent us this validation
     */
    virtual std::set<Peer::id_t>
    relay(
        protocol::TMValidation& m,
        uint256 const& uid,
        PublicKey const& validator) = 0;

    /** Relay a transaction. If the tx reduce-relay feature is enabled then
     * randomly select peers to relay to and queue transaction's hash
     * for the rest of the peers.
     * @param hash transaction's hash
     * @param m transaction's protocol message to relay
     * @param toSkip peers which have already seen this transaction
     */
    virtual void
    relay(
        uint256 const& hash,
        std::optional<std::reference_wrapper<protocol::TMTransaction>> m,
        std::set<Peer::id_t> const& toSkip) = 0;

    /** Visit every active peer.
     *
     * The visitor must be invocable as:
     *     Function(std::shared_ptr<Peer> const& peer);
     *
     * @param f the invocable to call with every peer
     */
    template <class Function>
    void
    foreach(Function f) const
    {
        for (auto const& p : getActivePeers())
            f(p);
    }

    /** Increment and retrieve counter for transaction job queue overflows. */
    virtual void
    incJqTransOverflow() = 0;
    virtual std::uint64_t
    getJqTransOverflow() const = 0;

    /** Increment and retrieve counters for total peer disconnects, and
     * disconnects we initiate for excessive resource consumption.
     */
    virtual void
    incPeerDisconnect() = 0;
    virtual std::uint64_t
    getPeerDisconnect() const = 0;
    virtual void
    incPeerDisconnectCharges() = 0;
    virtual std::uint64_t
    getPeerDisconnectCharges() const = 0;

    /** Returns the ID of the network this server is configured for, if any.

        The ID is just a numerical identifier, with the IDs 0, 1 and 2 used to
        identify the mainnet, the testnet and the devnet respectively.

        @return The numerical identifier configured by the administrator of the
                server. An unseated optional, otherwise.
    */
    virtual std::optional<std::uint32_t>
    networkID() const = 0;

    /** Returns tx reduce-relay metrics
        @return json value of tx reduce-relay metrics
     */
    virtual Json::Value
    txMetrics() const = 0;
};

}  // namespace xrpl

#endif