validation.h

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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2020 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_VALIDATION_H
#define BITCOIN_VALIDATION_H

#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif

#include <amount.h>
#include <attributes.h>
#include <coins.h>
#include <consensus/validation.h>
#include <crypto/common.h> // for ReadLE64
#include <fs.h>
#include <node/utxo_snapshot.h>
#include <policy/feerate.h>
#include <policy/packages.h>
#include <protocol.h> // For CMessageHeader::MessageStartChars
#include <script/script_error.h>
#include <sync.h>
#include <txmempool.h> // For CTxMemPool::cs
#include <txdb.h>
#include <serialize.h>
#include <util/check.h>
#include <util/hasher.h>
#include <util/translation.h>

#include <atomic>
#include <map>
#include <memory>
#include <optional>
#include <set>
#include <stdint.h>
#include <string>
#include <thread>
#include <utility>
#include <vector>

class CChainState;
class BlockValidationState;
class CBlockIndex;
class CBlockTreeDB;
class CBlockUndo;
class CChainParams;
struct CCheckpointData;
class CInv;
class CConnman;
class CScriptCheck;
class CTxMemPool;
class ChainstateManager;
struct ChainTxData;

struct DisconnectedBlockTransactions;
struct PrecomputedTransactionData;
struct LockPoints;
struct AssumeutxoData;

static const unsigned int DEFAULT_MIN_RELAY_TX_FEE = 1000;
static const unsigned int DEFAULT_ANCESTOR_LIMIT = 25;
static const unsigned int DEFAULT_ANCESTOR_SIZE_LIMIT = 101;
static const unsigned int DEFAULT_DESCENDANT_LIMIT = 25;
static const unsigned int DEFAULT_DESCENDANT_SIZE_LIMIT = 101;
static const unsigned int DEFAULT_MEMPOOL_EXPIRY = 336;
static const int MAX_SCRIPTCHECK_THREADS = 15;
static const int DEFAULT_SCRIPTCHECK_THREADS = 0;
static const int64_t DEFAULT_MAX_TIP_AGE = 24 * 60 * 60;
static const bool DEFAULT_CHECKPOINTS_ENABLED = true;
static const bool DEFAULT_TXINDEX = false;
static constexpr bool DEFAULT_COINSTATSINDEX{false};
static const char* const DEFAULT_BLOCKFILTERINDEX = "0";
static const bool DEFAULT_PERSIST_MEMPOOL = true;
static const int DEFAULT_STOPATHEIGHT = 0;
static const unsigned int MIN_BLOCKS_TO_KEEP = 288;
static const signed int DEFAULT_CHECKBLOCKS = 6;
static const unsigned int DEFAULT_CHECKLEVEL = 3;
// Require that user allocate at least 550 MiB for block & undo files (blk???.dat and rev???.dat)
// At 1MB per block, 288 blocks = 288MB.
// Add 15% for Undo data = 331MB
// Add 20% for Orphan block rate = 397MB
// We want the low water mark after pruning to be at least 397 MB and since we prune in
// full block file chunks, we need the high water mark which triggers the prune to be
// one 128MB block file + added 15% undo data = 147MB greater for a total of 545MB
// Setting the target to >= 550 MiB will make it likely we can respect the target.
static const uint64_t MIN_DISK_SPACE_FOR_BLOCK_FILES = 550 * 1024 * 1024;

enum class SynchronizationState {
    INIT_REINDEX,
    INIT_DOWNLOAD,
    POST_INIT
};

extern RecursiveMutex cs_main;
typedef std::unordered_map<uint256, CBlockIndex*, BlockHasher> BlockMap;
extern Mutex g_best_block_mutex;
extern std::condition_variable g_best_block_cv;
extern uint256 g_best_block;
extern bool g_parallel_script_checks;
extern bool fRequireStandard;
extern bool fCheckBlockIndex;
extern bool fCheckpointsEnabled;
extern CFeeRate minRelayTxFee;
extern int64_t nMaxTipAge;

extern uint256 hashAssumeValid;

extern arith_uint256 nMinimumChainWork;

extern CBlockIndex *pindexBestHeader;

extern const std::vector<std::string> CHECKLEVEL_DOC;

void UnloadBlockIndex(CTxMemPool* mempool, ChainstateManager& chainman);
void StartScriptCheckWorkerThreads(int threads_num);
void StopScriptCheckWorkerThreads();
CTransactionRef GetTransaction(const CBlockIndex* const block_index, const CTxMemPool* const mempool, const uint256& hash, const Consensus::Params& consensusParams, uint256& hashBlock);
CAmount GetBlockSubsidy(int nHeight, const Consensus::Params& consensusParams);

bool AbortNode(BlockValidationState& state, const std::string& strMessage, const bilingual_str& userMessage = bilingual_str{});

double GuessVerificationProgress(const ChainTxData& data, const CBlockIndex* pindex);

void PruneBlockFilesManual(CChainState& active_chainstate, int nManualPruneHeight);

struct MempoolAcceptResult {
    enum class ResultType {
        VALID, 
        INVALID, 
    };
    const ResultType m_result_type;
    const TxValidationState m_state;

    // The following fields are only present when m_result_type = ResultType::VALID
    const std::optional<std::list<CTransactionRef>> m_replaced_transactions;
    const std::optional<CAmount> m_base_fees;
    static MempoolAcceptResult Failure(TxValidationState state) {
        return MempoolAcceptResult(state);
    }

    static MempoolAcceptResult Success(std::list<CTransactionRef>&& replaced_txns, CAmount fees) {
        return MempoolAcceptResult(std::move(replaced_txns), fees);
    }

// Private constructors. Use static methods MempoolAcceptResult::Success, etc. to construct.
private:
    explicit MempoolAcceptResult(TxValidationState state)
        : m_result_type(ResultType::INVALID), m_state(state) {
            Assume(!state.IsValid()); // Can be invalid or error
        }

    explicit MempoolAcceptResult(std::list<CTransactionRef>&& replaced_txns, CAmount fees)
        : m_result_type(ResultType::VALID),
        m_replaced_transactions(std::move(replaced_txns)), m_base_fees(fees) {}
};

struct PackageMempoolAcceptResult
{
    const PackageValidationState m_state;
    std::map<const uint256, const MempoolAcceptResult> m_tx_results;

    explicit PackageMempoolAcceptResult(PackageValidationState state,
                                        std::map<const uint256, const MempoolAcceptResult>&& results)
        : m_state{state}, m_tx_results(std::move(results)) {}

    explicit PackageMempoolAcceptResult(const uint256& wtxid, const MempoolAcceptResult& result)
        : m_tx_results{ {wtxid, result} } {}
};

MempoolAcceptResult AcceptToMemoryPool(CChainState& active_chainstate, CTxMemPool& pool, const CTransactionRef& tx,
                                       bool bypass_limits, bool test_accept=false) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

PackageMempoolAcceptResult ProcessNewPackage(CChainState& active_chainstate, CTxMemPool& pool,
                                                   const Package& txns, bool test_accept)
                                                   EXCLUSIVE_LOCKS_REQUIRED(cs_main);

void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, int nHeight);

bool CheckFinalTx(const CBlockIndex* active_chain_tip, const CTransaction &tx, int flags = -1) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

bool TestLockPointValidity(CChain& active_chain, const LockPoints* lp) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

bool CheckSequenceLocks(CBlockIndex* tip,
                        const CCoinsView& coins_view,
                        const CTransaction& tx,
                        int flags,
                        LockPoints* lp = nullptr,
                        bool useExistingLockPoints = false);

class CScriptCheck
{
private:
    CTxOut m_tx_out;
    const CTransaction *ptxTo;
    unsigned int nIn;
    unsigned int nFlags;
    bool cacheStore;
    ScriptError error;
    PrecomputedTransactionData *txdata;

public:
    CScriptCheck(): ptxTo(nullptr), nIn(0), nFlags(0), cacheStore(false), error(SCRIPT_ERR_UNKNOWN_ERROR) {}
    CScriptCheck(const CTxOut& outIn, const CTransaction& txToIn, unsigned int nInIn, unsigned int nFlagsIn, bool cacheIn, PrecomputedTransactionData* txdataIn) :
        m_tx_out(outIn), ptxTo(&txToIn), nIn(nInIn), nFlags(nFlagsIn), cacheStore(cacheIn), error(SCRIPT_ERR_UNKNOWN_ERROR), txdata(txdataIn) { }

    bool operator()();

    void swap(CScriptCheck &check) {
        std::swap(ptxTo, check.ptxTo);
        std::swap(m_tx_out, check.m_tx_out);
        std::swap(nIn, check.nIn);
        std::swap(nFlags, check.nFlags);
        std::swap(cacheStore, check.cacheStore);
        std::swap(error, check.error);
        std::swap(txdata, check.txdata);
    }

    ScriptError GetScriptError() const { return error; }
};

void InitScriptExecutionCache();

bool CheckBlock(const CBlock& block, BlockValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW = true, bool fCheckMerkleRoot = true);

bool TestBlockValidity(BlockValidationState& state,
                       const CChainParams& chainparams,
                       CChainState& chainstate,
                       const CBlock& block,
                       CBlockIndex* pindexPrev,
                       bool fCheckPOW = true,
                       bool fCheckMerkleRoot = true) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

void UpdateUncommittedBlockStructures(CBlock& block, const CBlockIndex* pindexPrev, const Consensus::Params& consensusParams);

std::vector<unsigned char> GenerateCoinbaseCommitment(CBlock& block, const CBlockIndex* pindexPrev, const Consensus::Params& consensusParams);

class CVerifyDB {
public:
    CVerifyDB();
    ~CVerifyDB();
    bool VerifyDB(
        CChainState& chainstate,
        const CChainParams& chainparams,
        CCoinsView& coinsview,
        int nCheckLevel,
        int nCheckDepth) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
};

enum DisconnectResult
{
    DISCONNECT_OK,      // All good.
    DISCONNECT_UNCLEAN, // Rolled back, but UTXO set was inconsistent with block.
    DISCONNECT_FAILED   // Something else went wrong.
};

class ConnectTrace;

enum class FlushStateMode {
    NONE,
    IF_NEEDED,
    PERIODIC,
    ALWAYS
};

struct CBlockIndexWorkComparator
{
    bool operator()(const CBlockIndex *pa, const CBlockIndex *pb) const;
};

class BlockManager
{
    friend CChainState;

private:
    /* Calculate the block/rev files to delete based on height specified by user with RPC command pruneblockchain */
    void FindFilesToPruneManual(std::set<int>& setFilesToPrune, int nManualPruneHeight, int chain_tip_height);

    void FindFilesToPrune(std::set<int>& setFilesToPrune, uint64_t nPruneAfterHeight, int chain_tip_height, int prune_height, bool is_ibd);

public:
    BlockMap m_block_index GUARDED_BY(cs_main);

    std::set<CBlockIndex*> m_failed_blocks;

    std::multimap<CBlockIndex*, CBlockIndex*> m_blocks_unlinked;

    bool LoadBlockIndex(
        const Consensus::Params& consensus_params,
        CBlockTreeDB& blocktree,
        std::set<CBlockIndex*, CBlockIndexWorkComparator>& block_index_candidates)
        EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    void Unload() EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    CBlockIndex* AddToBlockIndex(const CBlockHeader& block) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    CBlockIndex* InsertBlockIndex(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    void PruneOneBlockFile(const int fileNumber) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    bool AcceptBlockHeader(
        const CBlockHeader& block,
        BlockValidationState& state,
        const CChainParams& chainparams,
        CBlockIndex** ppindex) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    CBlockIndex* LookupBlockIndex(const uint256& hash) const EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    CBlockIndex* FindForkInGlobalIndex(const CChain& chain, const CBlockLocator& locator) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    CBlockIndex* GetLastCheckpoint(const CCheckpointData& data) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    int GetSpendHeight(const CCoinsViewCache& inputs) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    ~BlockManager() {
        Unload();
    }
};

class CoinsViews {

public:
    CCoinsViewDB m_dbview GUARDED_BY(cs_main);

    CCoinsViewErrorCatcher m_catcherview GUARDED_BY(cs_main);

    std::unique_ptr<CCoinsViewCache> m_cacheview GUARDED_BY(cs_main);

    CoinsViews(std::string ldb_name, size_t cache_size_bytes, bool in_memory, bool should_wipe);

    void InitCache() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
};

enum class CoinsCacheSizeState
{
    CRITICAL = 2,
    LARGE = 1,
    OK = 0
};

class CChainState
{
protected:
    RecursiveMutex cs_nBlockSequenceId;
    int32_t nBlockSequenceId = 1;
    int32_t nBlockReverseSequenceId = -1;
    arith_uint256 nLastPreciousChainwork = 0;

    RecursiveMutex m_cs_chainstate;

    mutable std::atomic<bool> m_cached_finished_ibd{false};

    CTxMemPool* m_mempool;

    const CChainParams& m_params;

    std::unique_ptr<CoinsViews> m_coins_views;

public:
    BlockManager& m_blockman;

    explicit CChainState(
        CTxMemPool* mempool,
        BlockManager& blockman,
        std::optional<uint256> from_snapshot_blockhash = std::nullopt);

    void InitCoinsDB(
        size_t cache_size_bytes,
        bool in_memory,
        bool should_wipe,
        std::string leveldb_name = "chainstate");

    void InitCoinsCache(size_t cache_size_bytes) EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    bool CanFlushToDisk() const EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
        return m_coins_views && m_coins_views->m_cacheview;
    }

    CChain m_chain;

    const std::optional<uint256> m_from_snapshot_blockhash;

    std::set<CBlockIndex*, CBlockIndexWorkComparator> setBlockIndexCandidates;

    CCoinsViewCache& CoinsTip() EXCLUSIVE_LOCKS_REQUIRED(cs_main)
    {
        assert(m_coins_views->m_cacheview);
        return *m_coins_views->m_cacheview.get();
    }

    CCoinsViewDB& CoinsDB() EXCLUSIVE_LOCKS_REQUIRED(cs_main)
    {
        return m_coins_views->m_dbview;
    }

    CCoinsViewErrorCatcher& CoinsErrorCatcher() EXCLUSIVE_LOCKS_REQUIRED(cs_main)
    {
        return m_coins_views->m_catcherview;
    }

    void ResetCoinsViews() { m_coins_views.reset(); }

    size_t m_coinsdb_cache_size_bytes{0};

    size_t m_coinstip_cache_size_bytes{0};

    bool ResizeCoinsCaches(size_t coinstip_size, size_t coinsdb_size)
        EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    void LoadExternalBlockFile(FILE* fileIn, FlatFilePos* dbp = nullptr);

    bool FlushStateToDisk(
        BlockValidationState& state,
        FlushStateMode mode,
        int nManualPruneHeight = 0);

    void ForceFlushStateToDisk();

    void PruneAndFlush();

    bool ActivateBestChain(
        BlockValidationState& state,
        std::shared_ptr<const CBlock> pblock = nullptr) LOCKS_EXCLUDED(cs_main);

    bool AcceptBlock(const std::shared_ptr<const CBlock>& pblock, BlockValidationState& state, CBlockIndex** ppindex, bool fRequested, const FlatFilePos* dbp, bool* fNewBlock) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    // Block (dis)connection on a given view:
    DisconnectResult DisconnectBlock(const CBlock& block, const CBlockIndex* pindex, CCoinsViewCache& view);
    bool ConnectBlock(const CBlock& block, BlockValidationState& state, CBlockIndex* pindex,
                      CCoinsViewCache& view, bool fJustCheck = false) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    // Apply the effects of a block disconnection on the UTXO set.
    bool DisconnectTip(BlockValidationState& state, DisconnectedBlockTransactions* disconnectpool) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool->cs);

    // Manual block validity manipulation:
    bool PreciousBlock(BlockValidationState& state, CBlockIndex* pindex) LOCKS_EXCLUDED(cs_main);
    bool InvalidateBlock(BlockValidationState& state, CBlockIndex* pindex) LOCKS_EXCLUDED(cs_main);
    void ResetBlockFailureFlags(CBlockIndex* pindex) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    bool ReplayBlocks();

    [[nodiscard]] bool NeedsRedownload() const EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    bool LoadGenesisBlock();

    void PruneBlockIndexCandidates();

    void UnloadBlockIndex();

    bool IsInitialBlockDownload() const;

    void CheckBlockIndex();

    void LoadMempool(const ArgsManager& args);

    bool LoadChainTip() EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    CoinsCacheSizeState GetCoinsCacheSizeState() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    CoinsCacheSizeState GetCoinsCacheSizeState(
        size_t max_coins_cache_size_bytes,
        size_t max_mempool_size_bytes) EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    std::string ToString() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

private:
    bool ActivateBestChainStep(BlockValidationState& state, CBlockIndex* pindexMostWork, const std::shared_ptr<const CBlock>& pblock, bool& fInvalidFound, ConnectTrace& connectTrace) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool->cs);
    bool ConnectTip(BlockValidationState& state, CBlockIndex* pindexNew, const std::shared_ptr<const CBlock>& pblock, ConnectTrace& connectTrace, DisconnectedBlockTransactions& disconnectpool) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool->cs);

    void InvalidBlockFound(CBlockIndex* pindex, const BlockValidationState& state) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    CBlockIndex* FindMostWorkChain() EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    void ReceivedBlockTransactions(const CBlock& block, CBlockIndex* pindexNew, const FlatFilePos& pos) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    bool RollforwardBlock(const CBlockIndex* pindex, CCoinsViewCache& inputs) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    void CheckForkWarningConditions() EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    void InvalidChainFound(CBlockIndex* pindexNew) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    bool LoadBlockIndexDB() EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    RecursiveMutex* MempoolMutex() const LOCK_RETURNED(m_mempool->cs)
    {
        return m_mempool ? &m_mempool->cs : nullptr;
    }

    void MaybeUpdateMempoolForReorg(
        DisconnectedBlockTransactions& disconnectpool,
        bool fAddToMempool) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool->cs);

    void UpdateTip(const CBlockIndex* pindexNew)
        EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    friend ChainstateManager;
};

class ChainstateManager
{
private:
    std::unique_ptr<CChainState> m_ibd_chainstate GUARDED_BY(::cs_main);

    std::unique_ptr<CChainState> m_snapshot_chainstate GUARDED_BY(::cs_main);

    CChainState* m_active_chainstate GUARDED_BY(::cs_main) {nullptr};

    bool m_snapshot_validated{false};

    [[nodiscard]] bool PopulateAndValidateSnapshot(
        CChainState& snapshot_chainstate,
        CAutoFile& coins_file,
        const SnapshotMetadata& metadata);

public:
    std::thread m_load_block;
    BlockManager m_blockman GUARDED_BY(::cs_main);

    int64_t m_total_coinstip_cache{0};
    //
    int64_t m_total_coinsdb_cache{0};

    //                                  constructor
    CChainState& InitializeChainstate(
        CTxMemPool* mempool,
        const std::optional<uint256>& snapshot_blockhash = std::nullopt)
        EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    std::vector<CChainState*> GetAll();

    [[nodiscard]] bool ActivateSnapshot(
        CAutoFile& coins_file, const SnapshotMetadata& metadata, bool in_memory);

    CChainState& ActiveChainstate() const;
    CChain& ActiveChain() const { return ActiveChainstate().m_chain; }
    int ActiveHeight() const { return ActiveChain().Height(); }
    CBlockIndex* ActiveTip() const { return ActiveChain().Tip(); }

    BlockMap& BlockIndex() EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
    {
        return m_blockman.m_block_index;
    }

    bool IsSnapshotActive() const;

    std::optional<uint256> SnapshotBlockhash() const;

    bool IsSnapshotValidated() const { return m_snapshot_validated; }

    bool IsBackgroundIBD(CChainState* chainstate) const;

    CChainState& ValidatedChainstate() const;

    CChain& ValidatedChain() const { return ValidatedChainstate().m_chain; }
    CBlockIndex* ValidatedTip() const { return ValidatedChain().Tip(); }

    bool ProcessNewBlock(const CChainParams& chainparams, const std::shared_ptr<const CBlock>& block, bool force_processing, bool* new_block) LOCKS_EXCLUDED(cs_main);

    bool ProcessNewBlockHeaders(const std::vector<CBlockHeader>& block, BlockValidationState& state, const CChainParams& chainparams, const CBlockIndex** ppindex = nullptr) LOCKS_EXCLUDED(cs_main);

    bool LoadBlockIndex() EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    void Unload() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    void Reset();

    void MaybeRebalanceCaches() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    ~ChainstateManager() {
        LOCK(::cs_main);
        UnloadBlockIndex(/* mempool */ nullptr, *this);
        Reset();
    }
};

extern std::unique_ptr<CBlockTreeDB> pblocktree;

using FopenFn = std::function<FILE*(const fs::path&, const char*)>;

bool DumpMempool(const CTxMemPool& pool, FopenFn mockable_fopen_function = fsbridge::fopen, bool skip_file_commit = false);

bool LoadMempool(CTxMemPool& pool, CChainState& active_chainstate, FopenFn mockable_fopen_function = fsbridge::fopen);

const AssumeutxoData* ExpectedAssumeutxo(const int height, const CChainParams& params);

#endif // BITCOIN_VALIDATION_H