// Copyright (c) 2021-2022 The Bitcoin Core developers

// Distributed under the MIT software license, see the accompanying

// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_ADDRMAN_IMPL_H

#define BITCOIN_ADDRMAN_IMPL_H

#include <logging.h>

#include <logging/timer.h>

#include <netaddress.h>

#include <protocol.h>

#include <serialize.h>

#include <sync.h>

#include <uint256.h>

#include <util/time.h>

#include <cstdint>

#include <optional>

#include <set>

#include <unordered_map>

#include <unordered_set>

#include <utility>

#include <vector>

/** Total number of buckets for tried addresses */

static constexpr int32_t ADDRMAN_TRIED_BUCKET_COUNT_LOG2{8};

static constexpr int ADDRMAN_TRIED_BUCKET_COUNT{1 << ADDRMAN_TRIED_BUCKET_COUNT_LOG2};

/** Total number of buckets for new addresses */

static constexpr int32_t ADDRMAN_NEW_BUCKET_COUNT_LOG2{10};

static constexpr int ADDRMAN_NEW_BUCKET_COUNT{1 << ADDRMAN_NEW_BUCKET_COUNT_LOG2};

/** Maximum allowed number of entries in buckets for new and tried addresses */

static constexpr int32_t ADDRMAN_BUCKET_SIZE_LOG2{6};

static constexpr int ADDRMAN_BUCKET_SIZE{1 << ADDRMAN_BUCKET_SIZE_LOG2};

/**

 * User-defined type for the internally used nIds

 * This used to be int, making it feasible for attackers to cause an overflow,

 * see https://bitcoincore.org/en/2024/07/31/disclose-addrman-int-overflow/

 */

using nid_type = int64_t;

/**

 * Extended statistics about a CAddress

 */

class AddrInfo : public CAddress

{

public:

    //! last try whatsoever by us (memory only)

    NodeSeconds m_last_try{0s};

    //! last counted attempt (memory only)

    NodeSeconds m_last_count_attempt{0s};

    //! where knowledge about this address first came from

    CNetAddr source;

    //! last successful connection by us

    NodeSeconds m_last_success{0s};

    //! connection attempts since last successful attempt

    int nAttempts{0};

    //! reference count in new sets (memory only)

    int nRefCount{0};

    //! in tried set? (memory only)

    bool fInTried{false};

    //! position in vRandom

    mutable int nRandomPos{-1};

    SERIALIZE_METHODS(AddrInfo, obj)

    {

        READWRITE(AsBase<CAddress>(obj), obj.source, Using<ChronoFormatter<int64_t>>(obj.m_last_success), obj.nAttempts);

    }

Unexecuted instantiation: _ZN8AddrInfo16SerializationOpsI12ParamsStreamIR10DataStreamN8CAddress9SerParamsEES_17ActionUnserializeEEvRT0_RT_T1_

Unexecuted instantiation: _ZN8AddrInfo16SerializationOpsI12ParamsStreamIR18HashedSourceWriterI8AutoFileEN8CAddress9SerParamsEEKS_15ActionSerializeEEvRT0_RT_T1_

Unexecuted instantiation: _ZN8AddrInfo16SerializationOpsI12ParamsStreamIR10DataStreamN8CAddress9SerParamsEEKS_15ActionSerializeEEvRT0_RT_T1_

Unexecuted instantiation: _ZN8AddrInfo16SerializationOpsI12ParamsStreamIR8AutoFileN8CAddress9SerParamsEES_17ActionUnserializeEEvRT0_RT_T1_

Unexecuted instantiation: _ZN8AddrInfo16SerializationOpsI12ParamsStreamIR12HashVerifierI8AutoFileEN8CAddress9SerParamsEES_17ActionUnserializeEEvRT0_RT_T1_

Unexecuted instantiation: _ZN8AddrInfo16SerializationOpsI12ParamsStreamIR12HashVerifierI10DataStreamEN8CAddress9SerParamsEES_17ActionUnserializeEEvRT0_RT_T1_

    AddrInfo(const CAddress &addrIn, const CNetAddr &addrSource) : CAddress(addrIn), source(addrSource)

    {

    }

    AddrInfo() : CAddress(), source()

    {

    }

    //! Calculate in which "tried" bucket this entry belongs

    int GetTriedBucket(const uint256& nKey, const NetGroupManager& netgroupman) const;

    //! Calculate in which "new" bucket this entry belongs, given a certain source

    int GetNewBucket(const uint256& nKey, const CNetAddr& src, const NetGroupManager& netgroupman) const;

    //! Calculate in which "new" bucket this entry belongs, using its default source

    int GetNewBucket(const uint256& nKey, const NetGroupManager& netgroupman) const

    {

        return GetNewBucket(nKey, source, netgroupman);

    }

    //! Calculate in which position of a bucket to store this entry.

    int GetBucketPosition(const uint256 &nKey, bool fNew, int bucket) const;

    //! Determine whether the statistics about this entry are bad enough so that it can just be deleted

    bool IsTerrible(NodeSeconds now = Now<NodeSeconds>()) const;

    //! Calculate the relative chance this entry should be given when selecting nodes to connect to

    double GetChance(NodeSeconds now = Now<NodeSeconds>()) const;

};

class AddrManImpl

{

public:

    AddrManImpl(const NetGroupManager& netgroupman, bool deterministic, int32_t consistency_check_ratio);

    ~AddrManImpl();

    template <typename Stream>

    void Serialize(Stream& s_) const EXCLUSIVE_LOCKS_REQUIRED(!cs);

    template <typename Stream>

    void Unserialize(Stream& s_) EXCLUSIVE_LOCKS_REQUIRED(!cs);

    size_t Size(std::optional<Network> net, std::optional<bool> in_new) const EXCLUSIVE_LOCKS_REQUIRED(!cs);

    bool Add(const std::vector<CAddress>& vAddr, const CNetAddr& source, std::chrono::seconds time_penalty)

        EXCLUSIVE_LOCKS_REQUIRED(!cs);

    bool Good(const CService& addr, NodeSeconds time)

        EXCLUSIVE_LOCKS_REQUIRED(!cs);

    void Attempt(const CService& addr, bool fCountFailure, NodeSeconds time)

        EXCLUSIVE_LOCKS_REQUIRED(!cs);

    void ResolveCollisions() EXCLUSIVE_LOCKS_REQUIRED(!cs);

    std::pair<CAddress, NodeSeconds> SelectTriedCollision() EXCLUSIVE_LOCKS_REQUIRED(!cs);

    std::pair<CAddress, NodeSeconds> Select(bool new_only, const std::unordered_set<Network>& networks) const

        EXCLUSIVE_LOCKS_REQUIRED(!cs);

    std::vector<CAddress> GetAddr(size_t max_addresses, size_t max_pct, std::optional<Network> network, const bool filtered = true) const

        EXCLUSIVE_LOCKS_REQUIRED(!cs);

    std::vector<std::pair<AddrInfo, AddressPosition>> GetEntries(bool from_tried) const

        EXCLUSIVE_LOCKS_REQUIRED(!cs);

    void Connected(const CService& addr, NodeSeconds time)

        EXCLUSIVE_LOCKS_REQUIRED(!cs);

    void SetServices(const CService& addr, ServiceFlags nServices)

        EXCLUSIVE_LOCKS_REQUIRED(!cs);

    std::optional<AddressPosition> FindAddressEntry(const CAddress& addr)

        EXCLUSIVE_LOCKS_REQUIRED(!cs);

    friend class AddrManDeterministic;

private:

    //! A mutex to protect the inner data structures.

    mutable Mutex cs;

    //! Source of random numbers for randomization in inner loops

    mutable FastRandomContext insecure_rand GUARDED_BY(cs);

    //! secret key to randomize bucket select with

    uint256 nKey;

    //! Serialization versions.

    enum Format : uint8_t {

        V0_HISTORICAL = 0,    //!< historic format, before commit e6b343d88

        V1_DETERMINISTIC = 1, //!< for pre-asmap files

        V2_ASMAP = 2,         //!< for files including asmap version

        V3_BIP155 = 3,        //!< same as V2_ASMAP plus addresses are in BIP155 format

        V4_MULTIPORT = 4,     //!< adds support for multiple ports per IP

    };

    //! The maximum format this software knows it can unserialize. Also, we always serialize

    //! in this format.

    //! The format (first byte in the serialized stream) can be higher than this and

    //! still this software may be able to unserialize the file - if the second byte

    //! (see `lowest_compatible` in `Unserialize()`) is less or equal to this.

    static constexpr Format FILE_FORMAT = Format::V4_MULTIPORT;

    //! The initial value of a field that is incremented every time an incompatible format

    //! change is made (such that old software versions would not be able to parse and

    //! understand the new file format). This is 32 because we overtook the "key size"

    //! field which was 32 historically.

    //! @note Don't increment this. Increment `lowest_compatible` in `Serialize()` instead.

    static constexpr uint8_t INCOMPATIBILITY_BASE = 32;

    //! last used nId

    nid_type nIdCount GUARDED_BY(cs){0};

    //! table with information about all nIds

    std::unordered_map<nid_type, AddrInfo> mapInfo GUARDED_BY(cs);

    //! find an nId based on its network address and port.

    std::unordered_map<CService, nid_type, CServiceHash> mapAddr GUARDED_BY(cs);

    //! randomly-ordered vector of all nIds

    //! This is mutable because it is unobservable outside the class, so any

    //! changes to it (even in const methods) are also unobservable.

    mutable std::vector<nid_type> vRandom GUARDED_BY(cs);

    // number of "tried" entries

    int nTried GUARDED_BY(cs){0};

    //! list of "tried" buckets

    nid_type vvTried[ADDRMAN_TRIED_BUCKET_COUNT][ADDRMAN_BUCKET_SIZE] GUARDED_BY(cs);

    //! number of (unique) "new" entries

    int nNew GUARDED_BY(cs){0};

    //! list of "new" buckets

    nid_type vvNew[ADDRMAN_NEW_BUCKET_COUNT][ADDRMAN_BUCKET_SIZE] GUARDED_BY(cs);

    //! last time Good was called (memory only). Initially set to 1 so that "never" is strictly worse.

    NodeSeconds m_last_good GUARDED_BY(cs){1s};

    //! Holds addrs inserted into tried table that collide with existing entries. Test-before-evict discipline used to resolve these collisions.

    std::set<nid_type> m_tried_collisions;

    /** Perform consistency checks every m_consistency_check_ratio operations (if non-zero). */

    const int32_t m_consistency_check_ratio;

    /** Reference to the netgroup manager. netgroupman must be constructed before addrman and destructed after. */

    const NetGroupManager& m_netgroupman;

    struct NewTriedCount {

        size_t n_new;

        size_t n_tried;

    };

    /** Number of entries in addrman per network and new/tried table. */

    std::unordered_map<Network, NewTriedCount> m_network_counts GUARDED_BY(cs);

    //! Find an entry.

    AddrInfo* Find(const CService& addr, nid_type* pnId = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs);

    //! Create a new entry and add it to the internal data structures mapInfo, mapAddr and vRandom.

    AddrInfo* Create(const CAddress& addr, const CNetAddr& addrSource, nid_type* pnId = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs);

    //! Swap two elements in vRandom.

    void SwapRandom(unsigned int nRandomPos1, unsigned int nRandomPos2) const EXCLUSIVE_LOCKS_REQUIRED(cs);

    //! Delete an entry. It must not be in tried, and have refcount 0.

    void Delete(nid_type nId) EXCLUSIVE_LOCKS_REQUIRED(cs);

    //! Clear a position in a "new" table. This is the only place where entries are actually deleted.

    void ClearNew(int nUBucket, int nUBucketPos) EXCLUSIVE_LOCKS_REQUIRED(cs);

    //! Move an entry from the "new" table(s) to the "tried" table

    void MakeTried(AddrInfo& info, nid_type nId) EXCLUSIVE_LOCKS_REQUIRED(cs);

    /** Attempt to add a single address to addrman's new table.

     *  @see AddrMan::Add() for parameters. */

    bool AddSingle(const CAddress& addr, const CNetAddr& source, std::chrono::seconds time_penalty) EXCLUSIVE_LOCKS_REQUIRED(cs);

    bool Good_(const CService& addr, bool test_before_evict, NodeSeconds time) EXCLUSIVE_LOCKS_REQUIRED(cs);

    bool Add_(const std::vector<CAddress>& vAddr, const CNetAddr& source, std::chrono::seconds time_penalty) EXCLUSIVE_LOCKS_REQUIRED(cs);

    void Attempt_(const CService& addr, bool fCountFailure, NodeSeconds time) EXCLUSIVE_LOCKS_REQUIRED(cs);

    std::pair<CAddress, NodeSeconds> Select_(bool new_only, const std::unordered_set<Network>& networks) const EXCLUSIVE_LOCKS_REQUIRED(cs);

    /** Helper to generalize looking up an addrman entry from either table.

     *

     *  @return  nid_type The nid of the entry. If the addrman position is empty or not found, returns -1.

     * */

    nid_type GetEntry(bool use_tried, size_t bucket, size_t position) const EXCLUSIVE_LOCKS_REQUIRED(cs);

    std::vector<CAddress> GetAddr_(size_t max_addresses, size_t max_pct, std::optional<Network> network, const bool filtered = true) const EXCLUSIVE_LOCKS_REQUIRED(cs);

    std::vector<std::pair<AddrInfo, AddressPosition>> GetEntries_(bool from_tried) const EXCLUSIVE_LOCKS_REQUIRED(cs);

    void Connected_(const CService& addr, NodeSeconds time) EXCLUSIVE_LOCKS_REQUIRED(cs);

    void SetServices_(const CService& addr, ServiceFlags nServices) EXCLUSIVE_LOCKS_REQUIRED(cs);

    void ResolveCollisions_() EXCLUSIVE_LOCKS_REQUIRED(cs);

    std::pair<CAddress, NodeSeconds> SelectTriedCollision_() EXCLUSIVE_LOCKS_REQUIRED(cs);

    std::optional<AddressPosition> FindAddressEntry_(const CAddress& addr) EXCLUSIVE_LOCKS_REQUIRED(cs);

    size_t Size_(std::optional<Network> net, std::optional<bool> in_new) const EXCLUSIVE_LOCKS_REQUIRED(cs);

    //! Consistency check, taking into account m_consistency_check_ratio.

    //! Will std::abort if an inconsistency is detected.

    void Check() const EXCLUSIVE_LOCKS_REQUIRED(cs);

    //! Perform consistency check, regardless of m_consistency_check_ratio.

    //! @returns an error code or zero.

    int CheckAddrman() const EXCLUSIVE_LOCKS_REQUIRED(cs);

};

#endif // BITCOIN_ADDRMAN_IMPL_H