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 <coins.h>
#include <crypto/common.h> // for ReadLE64
#include <fs.h>
#include <optional.h>
#include <policy/feerate.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 <versionbits.h>
#include <serialize.h>

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

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

struct DisconnectedBlockTransactions;
struct PrecomputedTransactionData;
struct LockPoints;

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 unsigned int MAX_BLOCKFILE_SIZE = 0x8000000; // 128 MiB
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 const char* const DEFAULT_BLOCKFILTERINDEX = "0";
static const unsigned int DEFAULT_BANSCORE_THRESHOLD = 100;
static const bool DEFAULT_PERSIST_MEMPOOL = true;
static const bool DEFAULT_FEEFILTER = 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;
static constexpr size_t MINIMUM_WITNESS_COMMITMENT{38};

struct BlockHasher
{
    // this used to call `GetCheapHash()` in uint256, which was later moved; the
    // cheap hash function simply calls ReadLE64() however, so the end result is
    // identical
    size_t operator()(const uint256& hash) const { return ReadLE64(hash.begin()); }
};

enum class SynchronizationState {
    INIT_REINDEX,
    INIT_DOWNLOAD,
    POST_INIT
};

extern RecursiveMutex cs_main;
extern CBlockPolicyEstimator feeEstimator;
extern CTxMemPool mempool;
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 std::atomic_bool fImporting;
extern std::atomic_bool fReindex;
extern bool g_parallel_script_checks;
extern bool fRequireStandard;
extern bool fCheckBlockIndex;
extern bool fCheckpointsEnabled;
extern size_t nCoinCacheUsage;
extern CFeeRate minRelayTxFee;
extern int64_t nMaxTipAge;

extern uint256 hashAssumeValid;

extern arith_uint256 nMinimumChainWork;

extern CBlockIndex *pindexBestHeader;

extern bool fHavePruned;
extern bool fPruneMode;
extern uint64_t nPruneTarget;
extern const std::vector<std::string> CHECKLEVEL_DOC;

FILE* OpenBlockFile(const FlatFilePos &pos, bool fReadOnly = false);
fs::path GetBlockPosFilename(const FlatFilePos &pos);
void LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, FlatFilePos* dbp = nullptr);
bool LoadGenesisBlock(const CChainParams& chainparams);
void UnloadBlockIndex();
void ThreadScriptCheck(int worker_num);
bool GetTransaction(const uint256& hash, CTransactionRef& tx, const Consensus::Params& params, uint256& hashBlock, const CBlockIndex* const blockIndex = nullptr);
bool ActivateBestChain(BlockValidationState& state, const CChainParams& chainparams, std::shared_ptr<const CBlock> pblock = std::shared_ptr<const CBlock>());
CAmount GetBlockSubsidy(int nHeight, const Consensus::Params& consensusParams);

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

uint64_t CalculateCurrentUsage();

void UnlinkPrunedFiles(const std::set<int>& setFilesToPrune);

void PruneBlockFilesManual(int nManualPruneHeight);

bool AcceptToMemoryPool(CTxMemPool& pool, TxValidationState &state, const CTransactionRef &tx,
                        std::list<CTransactionRef>* plTxnReplaced,
                        bool bypass_limits, const CAmount nAbsurdFee, bool test_accept=false) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

ThresholdState VersionBitsTipState(const Consensus::Params& params, Consensus::DeploymentPos pos);

BIP9Stats VersionBitsTipStatistics(const Consensus::Params& params, Consensus::DeploymentPos pos);

int VersionBitsTipStateSinceHeight(const Consensus::Params& params, Consensus::DeploymentPos pos);


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

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

bool TestLockPointValidity(const LockPoints* lp) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

bool CheckSequenceLocks(const CTxMemPool& pool, const CTransaction& tx, int flags, LockPoints* lp = nullptr, bool useExistingLockPoints = false) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

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 ReadBlockFromDisk(CBlock& block, const FlatFilePos& pos, const Consensus::Params& consensusParams);
bool ReadBlockFromDisk(CBlock& block, const CBlockIndex* pindex, const Consensus::Params& consensusParams);
bool ReadRawBlockFromDisk(std::vector<uint8_t>& block, const FlatFilePos& pos, const CMessageHeader::MessageStartChars& message_start);
bool ReadRawBlockFromDisk(std::vector<uint8_t>& block, const CBlockIndex* pindex, const CMessageHeader::MessageStartChars& message_start);

bool UndoReadFromDisk(CBlockUndo& blockundo, const CBlockIndex* pindex);

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

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

bool IsWitnessEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params);

int GetWitnessCommitmentIndex(const CBlock& block);

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(const CChainParams& chainparams, CCoinsView *coinsview, int nCheckLevel, int nCheckDepth);
};

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

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

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

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 {
private:

    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};

    BlockManager& m_blockman;

    std::unique_ptr<CoinsViews> m_coins_views;

public:
    explicit CChainState(BlockManager& blockman, uint256 from_snapshot_blockhash = uint256());

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

    void InitCoinsCache() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

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

    CChain m_chain;

    const 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(); }

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

    void ForceFlushStateToDisk();

    void PruneAndFlush();

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

    bool AcceptBlock(const std::shared_ptr<const CBlock>& pblock, BlockValidationState& state, const CChainParams& chainparams, 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, const CChainParams& chainparams, bool fJustCheck = false) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    // Apply the effects of a block disconnection on the UTXO set.
    bool DisconnectTip(BlockValidationState& state, const CChainParams& chainparams, DisconnectedBlockTransactions* disconnectpool) EXCLUSIVE_LOCKS_REQUIRED(cs_main, ::mempool.cs);

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

    bool ReplayBlocks(const CChainParams& params);
    bool RewindBlockIndex(const CChainParams& params) LOCKS_EXCLUDED(cs_main);
    bool LoadGenesisBlock(const CChainParams& chainparams);

    void PruneBlockIndexCandidates();

    void UnloadBlockIndex();

    bool IsInitialBlockDownload() const;

    void CheckBlockIndex(const Consensus::Params& consensusParams);

    bool LoadChainTip(const CChainParams& chainparams) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    CoinsCacheSizeState GetCoinsCacheSizeState(const CTxMemPool& tx_pool)
        EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    CoinsCacheSizeState GetCoinsCacheSizeState(
        const CTxMemPool& tx_pool,
        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, const CChainParams& chainparams, CBlockIndex* pindexMostWork, const std::shared_ptr<const CBlock>& pblock, bool& fInvalidFound, ConnectTrace& connectTrace) EXCLUSIVE_LOCKS_REQUIRED(cs_main, ::mempool.cs);
    bool ConnectTip(BlockValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexNew, const std::shared_ptr<const CBlock>& pblock, ConnectTrace& connectTrace, DisconnectedBlockTransactions& disconnectpool) EXCLUSIVE_LOCKS_REQUIRED(cs_main, ::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, const Consensus::Params& consensusParams) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

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

    void EraseBlockData(CBlockIndex* index) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    friend ChainstateManager;
};

bool PreciousBlock(BlockValidationState& state, const CChainParams& params, CBlockIndex *pindex) LOCKS_EXCLUDED(cs_main);

bool InvalidateBlock(BlockValidationState& state, const CChainParams& chainparams, CBlockIndex* pindex) LOCKS_EXCLUDED(cs_main);

void ResetBlockFailureFlags(CBlockIndex* pindex) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

class ChainstateManager
{
private:
    std::unique_ptr<CChainState> m_ibd_chainstate;

    std::unique_ptr<CChainState> m_snapshot_chainstate;

    CChainState* m_active_chainstate{nullptr};

    bool m_snapshot_validated{false};

    // For access to m_active_chainstate.
    friend CChainState& ChainstateActive();
    friend CChain& ChainActive();

public:
    BlockManager m_blockman GUARDED_BY(::cs_main);

    CChainState& InitializeChainstate(const uint256& snapshot_blockhash = uint256())
        EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

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

    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;

    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> pblock, bool fForceProcessing, bool* fNewBlock) LOCKS_EXCLUDED(cs_main);

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

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

    bool LoadBlockIndex(const CChainParams& chainparams) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

    void Unload() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

    void Reset();
};

extern ChainstateManager g_chainman GUARDED_BY(::cs_main);

CChainState& ChainstateActive();

CChain& ChainActive();

extern std::unique_ptr<CBlockTreeDB> pblocktree;

int GetSpendHeight(const CCoinsViewCache& inputs);

extern VersionBitsCache versionbitscache;

int32_t ComputeBlockVersion(const CBlockIndex* pindexPrev, const Consensus::Params& params);

CBlockFileInfo* GetBlockFileInfo(size_t n);

bool DumpMempool(const CTxMemPool& pool);

bool LoadMempool(CTxMemPool& pool);

inline bool IsBlockPruned(const CBlockIndex* pblockindex)
{
    return (fHavePruned && !(pblockindex->nStatus & BLOCK_HAVE_DATA) && pblockindex->nTx > 0);
}

#endif // BITCOIN_VALIDATION_H