HashRouter.h

//------------------------------------------------------------------------------
/*
    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.
*/
//==============================================================================
 
#ifndef RIPPLE_APP_MISC_HASHROUTER_H_INCLUDED
#define RIPPLE_APP_MISC_HASHROUTER_H_INCLUDED
 
#include <xrpl/basics/CountedObject.h>
#include <xrpl/basics/UnorderedContainers.h>
#include <xrpl/basics/base_uint.h>
#include <xrpl/basics/chrono.h>
#include <xrpl/beast/container/aged_unordered_map.h>
 
#include <optional>
#include <set>
 
namespace ripple {
 
enum class HashRouterFlags : std::uint16_t {
    // Public flags
    UNDEFINED = 0x00,
    BAD = 0x02,  // Temporarily bad
    SAVED = 0x04,
    HELD = 0x08,     // Held by LedgerMaster after potential processing failure
    TRUSTED = 0x10,  // Comes from a trusted source
 
    // Private flags (used internally in apply.cpp)
    // Do not attempt to read, set, or reuse.
    PRIVATE1 = 0x0100,
    PRIVATE2 = 0x0200,
    PRIVATE3 = 0x0400,
    PRIVATE4 = 0x0800,
    PRIVATE5 = 0x1000,
    PRIVATE6 = 0x2000
};
 
constexpr HashRouterFlags
operator|(HashRouterFlags lhs, HashRouterFlags rhs)
{
    return static_cast<HashRouterFlags>(
        static_cast<std::underlying_type_t<HashRouterFlags>>(lhs) |
        static_cast<std::underlying_type_t<HashRouterFlags>>(rhs));
}
 
constexpr HashRouterFlags&
operator|=(HashRouterFlags& lhs, HashRouterFlags rhs)
{
    lhs = lhs | rhs;
    return lhs;
}
 
constexpr HashRouterFlags
operator&(HashRouterFlags lhs, HashRouterFlags rhs)
{
    return static_cast<HashRouterFlags>(
        static_cast<std::underlying_type_t<HashRouterFlags>>(lhs) &
        static_cast<std::underlying_type_t<HashRouterFlags>>(rhs));
}
 
constexpr HashRouterFlags&
operator&=(HashRouterFlags& lhs, HashRouterFlags rhs)
{
    lhs = lhs & rhs;
    return lhs;
}
 
constexpr bool
any(HashRouterFlags flags)
{
    return static_cast<std::underlying_type_t<HashRouterFlags>>(flags) != 0;
}
 
class Config;
 
class HashRouter
{
public:
    // The type here *MUST* match the type of Peer::id_t
    using PeerShortID = std::uint32_t;
 
    struct Setup
    {
        explicit Setup() = default;
 
        using seconds = std::chrono::seconds;
 
        seconds holdTime{300};
 
        seconds relayTime{30};
    };
 
private:
    class Entry : public CountedObject<Entry>
    {
    public:
        Entry()
        {
        }
 
        void
        addPeer(PeerShortID peer)
        {
            if (peer != 0)
                peers_.insert(peer);
        }
 
        HashRouterFlags
        getFlags(void) const
        {
            return flags_;
        }
 
        void
        setFlags(HashRouterFlags flagsToSet)
        {
            flags_ |= flagsToSet;
        }
 
        std::set<PeerShortID>
        releasePeerSet()
        {
            return std::move(peers_);
        }
 
        std::optional<Stopwatch::time_point>
        relayed() const
        {
            return relayed_;
        }
 
        bool
        shouldRelay(
            Stopwatch::time_point const& now,
            std::chrono::seconds relayTime)
        {
            if (relayed_ && *relayed_ + relayTime > now)
                return false;
            relayed_.emplace(now);
            return true;
        }
 
        bool
        shouldProcess(Stopwatch::time_point now, std::chrono::seconds interval)
        {
            if (processed_ && ((*processed_ + interval) > now))
                return false;
            processed_.emplace(now);
            return true;
        }
 
    private:
        HashRouterFlags flags_ = HashRouterFlags::UNDEFINED;
        std::set<PeerShortID> peers_;
        // This could be generalized to a map, if more
        // than one flag needs to expire independently.
        std::optional<Stopwatch::time_point> relayed_;
        std::optional<Stopwatch::time_point> processed_;
    };
 
public:
    HashRouter(Setup const& setup, Stopwatch& clock)
        : setup_(setup), suppressionMap_(clock)
    {
    }
 
    HashRouter&
    operator=(HashRouter const&) = delete;
 
    virtual ~HashRouter() = default;
 
    // VFALCO TODO Replace "Supression" terminology with something more
    // semantically meaningful.
    void
    addSuppression(uint256 const& key);
 
    bool
    addSuppressionPeer(uint256 const& key, PeerShortID peer);
 
    std::pair<bool, std::optional<Stopwatch::time_point>>
    addSuppressionPeerWithStatus(uint256 const& key, PeerShortID peer);
 
    bool
    addSuppressionPeer(
        uint256 const& key,
        PeerShortID peer,
        HashRouterFlags& flags);
 
    // Add a peer suppression and return whether the entry should be processed
    bool
    shouldProcess(
        uint256 const& key,
        PeerShortID peer,
        HashRouterFlags& flags,
        std::chrono::seconds tx_interval);
 
    bool
    setFlags(uint256 const& key, HashRouterFlags flags);
 
    HashRouterFlags
    getFlags(uint256 const& key);
 
    std::optional<std::set<PeerShortID>>
    shouldRelay(uint256 const& key);
 
private:
    // pair.second indicates whether the entry was created
    std::pair<Entry&, bool>
    emplace(uint256 const&);
 
    std::mutex mutable mutex_;
 
    // Configurable parameters
    Setup const setup_;
 
    // Stores all suppressed hashes and their expiration time
    beast::aged_unordered_map<
        uint256,
        Entry,
        Stopwatch::clock_type,
        hardened_hash<strong_hash>>
        suppressionMap_;
};
 
HashRouter::Setup
setup_HashRouter(Config const&);
 
}  // namespace ripple
 
#endif