src/validation.h

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2016 The Bitcoin Core developers
   3 // Distributed under the MIT software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 #ifndef BITCOIN_VALIDATION_H
   7 #define BITCOIN_VALIDATION_H
   8
   9 #if defined(HAVE_CONFIG_H)
  10 #include "config/bitcoin-config.h"
  11 #endif
  12
  13 #include "amount.h"
  14 #include "coins.h"
  15 #include "fs.h"
  16 #include "protocol.h" // For CMessageHeader::MessageStartChars
  17 #include "policy/feerate.h"
  18 #include "script/script_error.h"
  19 #include "sync.h"
  20 #include "versionbits.h"
  21
  22 #include <algorithm>
  23 #include <exception>
  24 #include <map>
  25 #include <set>
  26 #include <stdint.h>
  27 #include <string>
  28 #include <utility>
  29 #include <vector>
  30
  31 #include <atomic>
  32
  33 class CBlockIndex;
  34 class CBlockTreeDB;
  35 class CChainParams;
  36 class CCoinsViewDB;
  37 class CInv;
  38 class CConnman;
  39 class CScriptCheck;
  40 class CBlockPolicyEstimator;
  41 class CTxMemPool;
  42 class CValidationState;
  43 struct ChainTxData;
  44
  45 struct PrecomputedTransactionData;
  46 struct LockPoints;
  47
  48 /** Default for DEFAULT_WHITELISTRELAY. */
  49 static const bool DEFAULT_WHITELISTRELAY = true;
  50 /** Default for DEFAULT_WHITELISTFORCERELAY. */
  51 static const bool DEFAULT_WHITELISTFORCERELAY = true;
  52 /** Default for -minrelaytxfee, minimum relay fee for transactions */
  53 static const unsigned int DEFAULT_MIN_RELAY_TX_FEE = 1000;
  54 //! -maxtxfee default
  55 static const CAmount DEFAULT_TRANSACTION_MAXFEE = 0.1 * COIN;
  56 //! Discourage users to set fees higher than this amount (in satoshis) per kB
  57 static const CAmount HIGH_TX_FEE_PER_KB = 0.01 * COIN;
  58 //! -maxtxfee will warn if called with a higher fee than this amount (in satoshis)
  59 static const CAmount HIGH_MAX_TX_FEE = 100 * HIGH_TX_FEE_PER_KB;
  60 /** Default for -limitancestorcount, max number of in-mempool ancestors */
  61 static const unsigned int DEFAULT_ANCESTOR_LIMIT = 25;
  62 /** Default for -limitancestorsize, maximum kilobytes of tx + all in-mempool ancestors */
  63 static const unsigned int DEFAULT_ANCESTOR_SIZE_LIMIT = 101;
  64 /** Default for -limitdescendantcount, max number of in-mempool descendants */
  65 static const unsigned int DEFAULT_DESCENDANT_LIMIT = 25;
  66 /** Default for -limitdescendantsize, maximum kilobytes of in-mempool descendants */
  67 static const unsigned int DEFAULT_DESCENDANT_SIZE_LIMIT = 101;
  68 /** Default for -mempoolexpiry, expiration time for mempool transactions in hours */
  69 static const unsigned int DEFAULT_MEMPOOL_EXPIRY = 336;
  70 /** Maximum kilobytes for transactions to store for processing during reorg */
  71 static const unsigned int MAX_DISCONNECTED_TX_POOL_SIZE = 20000;
  72 /** The maximum size of a blk?????.dat file (since 0.8) */
  73 static const unsigned int MAX_BLOCKFILE_SIZE = 0x8000000; // 128 MiB
  74 /** The pre-allocation chunk size for blk?????.dat files (since 0.8) */
  75 static const unsigned int BLOCKFILE_CHUNK_SIZE = 0x1000000; // 16 MiB
  76 /** The pre-allocation chunk size for rev?????.dat files (since 0.8) */
  77 static const unsigned int UNDOFILE_CHUNK_SIZE = 0x100000; // 1 MiB
  78
  79 /** Maximum number of script-checking threads allowed */
  80 static const int MAX_SCRIPTCHECK_THREADS = 16;
  81 /** -par default (number of script-checking threads, 0 = auto) */
  82 static const int DEFAULT_SCRIPTCHECK_THREADS = 0;
  83 /** Number of blocks that can be requested at any given time from a single peer. */
  84 static const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 16;
  85 /** Timeout in seconds during which a peer must stall block download progress before being disconnected. */
  86 static const unsigned int BLOCK_STALLING_TIMEOUT = 2;
  87 /** Number of headers sent in one getheaders result. We rely on the assumption that if a peer sends
  88  *  less than this number, we reached its tip. Changing this value is a protocol upgrade. */
  89 static const unsigned int MAX_HEADERS_RESULTS = 2000;
  90 /** Maximum depth of blocks we're willing to serve as compact blocks to peers
  91  *  when requested. For older blocks, a regular BLOCK response will be sent. */
  92 static const int MAX_CMPCTBLOCK_DEPTH = 5;
  93 /** Maximum depth of blocks we're willing to respond to GETBLOCKTXN requests for. */
  94 static const int MAX_BLOCKTXN_DEPTH = 10;
  95 /** Size of the "block download window": how far ahead of our current height do we fetch?
  96  *  Larger windows tolerate larger download speed differences between peer, but increase the potential
  97  *  degree of disordering of blocks on disk (which make reindexing and in the future perhaps pruning
  98  *  harder). We'll probably want to make this a per-peer adaptive value at some point. */
  99 static const unsigned int BLOCK_DOWNLOAD_WINDOW = 1024;
 100 /** Time to wait (in seconds) between writing blocks/block index to disk. */
 101 static const unsigned int DATABASE_WRITE_INTERVAL = 60 * 60;
 102 /** Time to wait (in seconds) between flushing chainstate to disk. */
 103 static const unsigned int DATABASE_FLUSH_INTERVAL = 24 * 60 * 60;
 104 /** Maximum length of reject messages. */
 105 static const unsigned int MAX_REJECT_MESSAGE_LENGTH = 111;
 106 /** Average delay between local address broadcasts in seconds. */
 107 static const unsigned int AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL = 24 * 60 * 60;
 108 /** Average delay between peer address broadcasts in seconds. */
 109 static const unsigned int AVG_ADDRESS_BROADCAST_INTERVAL = 30;
 110 /** Average delay between trickled inventory transmissions in seconds.
 111  *  Blocks and whitelisted receivers bypass this, outbound peers get half this delay. */
 112 static const unsigned int INVENTORY_BROADCAST_INTERVAL = 5;
 113 /** Maximum number of inventory items to send per transmission.
 114  *  Limits the impact of low-fee transaction floods. */
 115 static const unsigned int INVENTORY_BROADCAST_MAX = 7 * INVENTORY_BROADCAST_INTERVAL;
 116 /** Average delay between feefilter broadcasts in seconds. */
 117 static const unsigned int AVG_FEEFILTER_BROADCAST_INTERVAL = 10 * 60;
 118 /** Maximum feefilter broadcast delay after significant change. */
 119 static const unsigned int MAX_FEEFILTER_CHANGE_DELAY = 5 * 60;
 120 /** Block download timeout base, expressed in millionths of the block interval (i.e. 10 min) */
 121 static const int64_t BLOCK_DOWNLOAD_TIMEOUT_BASE = 1000000;
 122 /** Additional block download timeout per parallel downloading peer (i.e. 5 min) */
 123 static const int64_t BLOCK_DOWNLOAD_TIMEOUT_PER_PEER = 500000;
 124
 125 static const int64_t DEFAULT_MAX_TIP_AGE = 24 * 60 * 60;
 126 /** Maximum age of our tip in seconds for us to be considered current for fee estimation */
 127 static const int64_t MAX_FEE_ESTIMATION_TIP_AGE = 3 * 60 * 60;
 128
 129 /** Default for -permitbaremultisig */
 130 static const bool DEFAULT_PERMIT_BAREMULTISIG = true;
 131 static const bool DEFAULT_CHECKPOINTS_ENABLED = true;
 132 static const bool DEFAULT_TXINDEX = false;
 133 static const unsigned int DEFAULT_BANSCORE_THRESHOLD = 100;
 134 /** Default for -persistmempool */
 135 static const bool DEFAULT_PERSIST_MEMPOOL = true;
 136 /** Default for -mempoolreplacement */
 137 static const bool DEFAULT_ENABLE_REPLACEMENT = true;
 138 /** Default for using fee filter */
 139 static const bool DEFAULT_FEEFILTER = true;
 140
 141 /** Maximum number of headers to announce when relaying blocks with headers message.*/
 142 static const unsigned int MAX_BLOCKS_TO_ANNOUNCE = 8;
 143
 144 /** Maximum number of unconnecting headers announcements before DoS score */
 145 static const int MAX_UNCONNECTING_HEADERS = 10;
 146
 147 static const bool DEFAULT_PEERBLOOMFILTERS = true;
 148
 149 /** Default for -stopatheight */
 150 static const int DEFAULT_STOPATHEIGHT = 0;
 151
 152 struct BlockHasher
 153 {
 154     size_t operator()(const uint256& hash) const { return hash.GetCheapHash(); }
 155 };
 156
 157 extern CScript COINBASE_FLAGS;
 158 extern CCriticalSection cs_main;
 159 extern CBlockPolicyEstimator feeEstimator;
 160 extern CTxMemPool mempool;
 161 typedef std::unordered_map<uint256, CBlockIndex*, BlockHasher> BlockMap;
 162 extern BlockMap mapBlockIndex;
 163 extern uint64_t nLastBlockTx;
 164 extern uint64_t nLastBlockWeight;
 165 extern const std::string strMessageMagic;
 166 extern CWaitableCriticalSection csBestBlock;
 167 extern CConditionVariable cvBlockChange;
 168 extern std::atomic_bool fImporting;
 169 extern bool fReindex;
 170 extern int nScriptCheckThreads;
 171 extern bool fTxIndex;
 172 extern bool fIsBareMultisigStd;
 173 extern bool fRequireStandard;
 174 extern bool fCheckBlockIndex;
 175 extern bool fCheckpointsEnabled;
 176 extern size_t nCoinCacheUsage;
 177 /** A fee rate smaller than this is considered zero fee (for relaying, mining and transaction creation) */
 178 extern CFeeRate minRelayTxFee;
 179 /** Absolute maximum transaction fee (in satoshis) used by wallet and mempool (rejects high fee in sendrawtransaction) */
 180 extern CAmount maxTxFee;
 181 /** If the tip is older than this (in seconds), the node is considered to be in initial block download. */
 182 extern int64_t nMaxTipAge;
 183 extern bool fEnableReplacement;
 184
 185 /** Block hash whose ancestors we will assume to have valid scripts without checking them. */
 186 extern uint256 hashAssumeValid;
 187
 188 /** Minimum work we will assume exists on some valid chain. */
 189 extern arith_uint256 nMinimumChainWork;
 190
 191 /** Best header we've seen so far (used for getheaders queries' starting points). */
 192 extern CBlockIndex *pindexBestHeader;
 193
 194 /** Minimum disk space required - used in CheckDiskSpace() */
 195 static const uint64_t nMinDiskSpace = 52428800;
 196
 197 /** Pruning-related variables and constants */
 198 /** True if any block files have ever been pruned. */
 199 extern bool fHavePruned;
 200 /** True if we're running in -prune mode. */
 201 extern bool fPruneMode;
 202 /** Number of MiB of block files that we're trying to stay below. */
 203 extern uint64_t nPruneTarget;
 204 /** Block files containing a block-height within MIN_BLOCKS_TO_KEEP of chainActive.Tip() will not be pruned. */
 205 static const unsigned int MIN_BLOCKS_TO_KEEP = 288;
 206
 207 static const signed int DEFAULT_CHECKBLOCKS = 6;
 208 static const unsigned int DEFAULT_CHECKLEVEL = 3;
 209
 210 // Require that user allocate at least 550MB for block & undo files (blk???.dat and rev???.dat)
 211 // At 1MB per block, 288 blocks = 288MB.
 212 // Add 15% for Undo data = 331MB
 213 // Add 20% for Orphan block rate = 397MB
 214 // We want the low water mark after pruning to be at least 397 MB and since we prune in
 215 // full block file chunks, we need the high water mark which triggers the prune to be
 216 // one 128MB block file + added 15% undo data = 147MB greater for a total of 545MB
 217 // Setting the target to > than 550MB will make it likely we can respect the target.
 218 static const uint64_t MIN_DISK_SPACE_FOR_BLOCK_FILES = 550 * 1024 * 1024;
 219
 220 /**
 221  * Process an incoming block. This only returns after the best known valid
 222  * block is made active. Note that it does not, however, guarantee that the
 223  * specific block passed to it has been checked for validity!
 224  *
 225  * If you want to *possibly* get feedback on whether pblock is valid, you must
 226  * install a CValidationInterface (see validationinterface.h) - this will have
 227  * its BlockChecked method called whenever *any* block completes validation.
 228  *
 229  * Note that we guarantee that either the proof-of-work is valid on pblock, or
 230  * (and possibly also) BlockChecked will have been called.
 231  *
 232  * Call without cs_main held.
 233  *
 234  * @param[in]   pblock  The block we want to process.
 235  * @param[in]   fForceProcessing Process this block even if unrequested; used for non-network block sources and whitelisted peers.
 236  * @param[out]  fNewBlock A boolean which is set to indicate if the block was first received via this call
 237  * @return True if state.IsValid()
 238  */
 239 bool ProcessNewBlock(const CChainParams& chainparams, const std::shared_ptr<const CBlock> pblock, bool fForceProcessing, bool* fNewBlock);
 240
 241 /**
 242  * Process incoming block headers.
 243  *
 244  * Call without cs_main held.
 245  *
 246  * @param[in]  block The block headers themselves
 247  * @param[out] state This may be set to an Error state if any error occurred processing them
 248  * @param[in]  chainparams The params for the chain we want to connect to
 249  * @param[out] ppindex If set, the pointer will be set to point to the last new block index object for the given headers
 250  */
 251 bool ProcessNewBlockHeaders(const std::vector<CBlockHeader>& block, CValidationState& state, const CChainParams& chainparams, const CBlockIndex** ppindex=nullptr);
 252
 253 /** Check whether enough disk space is available for an incoming block */
 254 bool CheckDiskSpace(uint64_t nAdditionalBytes = 0);
 255 /** Open a block file (blk?????.dat) */
 256 FILE* OpenBlockFile(const CDiskBlockPos &pos, bool fReadOnly = false);
 257 /** Translation to a filesystem path */
 258 fs::path GetBlockPosFilename(const CDiskBlockPos &pos, const char *prefix);
 259 /** Import blocks from an external file */
 260 bool LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskBlockPos *dbp = nullptr);
 261 /** Ensures we have a genesis block in the block tree, possibly writing one to disk. */
 262 bool LoadGenesisBlock(const CChainParams& chainparams);
 263 /** Load the block tree and coins database from disk,
 264  * initializing state if we're running with -reindex. */
 265 bool LoadBlockIndex(const CChainParams& chainparams);
 266 /** Update the chain tip based on database information. */
 267 bool LoadChainTip(const CChainParams& chainparams);
 268 /** Unload database information */
 269 void UnloadBlockIndex();
 270 /** Run an instance of the script checking thread */
 271 void ThreadScriptCheck();
 272 /** Check whether we are doing an initial block download (synchronizing from disk or network) */
 273 bool IsInitialBlockDownload();
 274 /** Retrieve a transaction (from memory pool, or from disk, if possible) */
 275 bool GetTransaction(const uint256 &hash, CTransactionRef &tx, const Consensus::Params& params, uint256 &hashBlock, bool fAllowSlow = false);
 276 /** Find the best known block, and make it the tip of the block chain */
 277 bool ActivateBestChain(CValidationState& state, const CChainParams& chainparams, std::shared_ptr<const CBlock> pblock = std::shared_ptr<const CBlock>());
 278 CAmount GetBlockSubsidy(int nHeight, const Consensus::Params& consensusParams);
 279
 280 /** Guess verification progress (as a fraction between 0.0=genesis and 1.0=current tip). */
 281 double GuessVerificationProgress(const ChainTxData& data, CBlockIndex* pindex);
 282
 283 /**
 284  *  Mark one block file as pruned.
 285  */
 286 void PruneOneBlockFile(const int fileNumber);
 287
 288 /**
 289  *  Actually unlink the specified files
 290  */
 291 void UnlinkPrunedFiles(const std::set<int>& setFilesToPrune);
 292
 293 /** Create a new block index entry for a given block hash */
 294 CBlockIndex * InsertBlockIndex(uint256 hash);
 295 /** Flush all state, indexes and buffers to disk. */
 296 void FlushStateToDisk();
 297 /** Prune block files and flush state to disk. */
 298 void PruneAndFlush();
 299 /** Prune block files up to a given height */
 300 void PruneBlockFilesManual(int nManualPruneHeight);
 301
 302 /** (try to) add transaction to memory pool
 303  * plTxnReplaced will be appended to with all transactions replaced from mempool **/
 304 bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransactionRef &tx, bool fLimitFree,
 305                         bool* pfMissingInputs, std::list<CTransactionRef>* plTxnReplaced = nullptr,
 306                         bool fOverrideMempoolLimit=false, const CAmount nAbsurdFee=0);
 307
 308 /** Convert CValidationState to a human-readable message for logging */
 309 std::string FormatStateMessage(const CValidationState &state);
 310
 311 /** Get the BIP9 state for a given deployment at the current tip. */
 312 ThresholdState VersionBitsTipState(const Consensus::Params& params, Consensus::DeploymentPos pos);
 313
 314 /** Get the numerical statistics for the BIP9 state for a given deployment at the current tip. */
 315 BIP9Stats VersionBitsTipStatistics(const Consensus::Params& params, Consensus::DeploymentPos pos);
 316
 317 /** Get the block height at which the BIP9 deployment switched into the state for the block building on the current tip. */
 318 int VersionBitsTipStateSinceHeight(const Consensus::Params& params, Consensus::DeploymentPos pos);
 319
 320
 321 /** Apply the effects of this transaction on the UTXO set represented by view */
 322 void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, int nHeight);
 323
 324 /** Transaction validation functions */
 325
 326 /**
 327  * Check if transaction will be final in the next block to be created.
 328  *
 329  * Calls IsFinalTx() with current block height and appropriate block time.
 330  *
 331  * See consensus/consensus.h for flag definitions.
 332  */
 333 bool CheckFinalTx(const CTransaction &tx, int flags = -1);
 334
 335 /**
 336  * Test whether the LockPoints height and time are still valid on the current chain
 337  */
 338 bool TestLockPointValidity(const LockPoints* lp);
 339
 340 /**
 341  * Check if transaction will be BIP 68 final in the next block to be created.
 342  *
 343  * Simulates calling SequenceLocks() with data from the tip of the current active chain.
 344  * Optionally stores in LockPoints the resulting height and time calculated and the hash
 345  * of the block needed for calculation or skips the calculation and uses the LockPoints
 346  * passed in for evaluation.
 347  * The LockPoints should not be considered valid if CheckSequenceLocks returns false.
 348  *
 349  * See consensus/consensus.h for flag definitions.
 350  */
 351 bool CheckSequenceLocks(const CTransaction &tx, int flags, LockPoints* lp = nullptr, bool useExistingLockPoints = false);
 352
 353 /**
 354  * Closure representing one script verification
 355  * Note that this stores references to the spending transaction
 356  */
 357 class CScriptCheck
 358 {
 359 private:
 360     CScript scriptPubKey;
 361     CAmount amount;
 362     const CTransaction *ptxTo;
 363     unsigned int nIn;
 364     unsigned int nFlags;
 365     bool cacheStore;
 366     ScriptError error;
 367     PrecomputedTransactionData *txdata;
 368
 369 public:
 370     CScriptCheck(): amount(0), ptxTo(nullptr), nIn(0), nFlags(0), cacheStore(false), error(SCRIPT_ERR_UNKNOWN_ERROR) {}
 371     CScriptCheck(const CScript& scriptPubKeyIn, const CAmount amountIn, const CTransaction& txToIn, unsigned int nInIn, unsigned int nFlagsIn, bool cacheIn, PrecomputedTransactionData* txdataIn) :
 372         scriptPubKey(scriptPubKeyIn), amount(amountIn),
 373         ptxTo(&txToIn), nIn(nInIn), nFlags(nFlagsIn), cacheStore(cacheIn), error(SCRIPT_ERR_UNKNOWN_ERROR), txdata(txdataIn) { }
 374
 375     bool operator()();
 376
 377     void swap(CScriptCheck &check) {
 378         scriptPubKey.swap(check.scriptPubKey);
 379         std::swap(ptxTo, check.ptxTo);
 380         std::swap(amount, check.amount);
 381         std::swap(nIn, check.nIn);
 382         std::swap(nFlags, check.nFlags);
 383         std::swap(cacheStore, check.cacheStore);
 384         std::swap(error, check.error);
 385         std::swap(txdata, check.txdata);
 386     }
 387
 388     ScriptError GetScriptError() const { return error; }
 389 };
 390
 391 /** Initializes the script-execution cache */
 392 void InitScriptExecutionCache();
 393
 394
 395 /** Functions for disk access for blocks */
 396 bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos, const Consensus::Params& consensusParams);
 397 bool ReadBlockFromDisk(CBlock& block, const CBlockIndex* pindex, const Consensus::Params& consensusParams);
 398
 399 /** Functions for validating blocks and updating the block tree */
 400
 401 /** Context-independent validity checks */
 402 bool CheckBlock(const CBlock& block, CValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW = true, bool fCheckMerkleRoot = true);
 403
 404 /** Check a block is completely valid from start to finish (only works on top of our current best block, with cs_main held) */
 405 bool TestBlockValidity(CValidationState& state, const CChainParams& chainparams, const CBlock& block, CBlockIndex* pindexPrev, bool fCheckPOW = true, bool fCheckMerkleRoot = true);
 406
 407 /** Check whether witness commitments are required for block. */
 408 bool IsWitnessEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params);
 409
 410 /** When there are blocks in the active chain with missing data, rewind the chainstate and remove them from the block index */
 411 bool RewindBlockIndex(const CChainParams& params);
 412
 413 /** Update uncommitted block structures (currently: only the witness nonce). This is safe for submitted blocks. */
 414 void UpdateUncommittedBlockStructures(CBlock& block, const CBlockIndex* pindexPrev, const Consensus::Params& consensusParams);
 415
 416 /** Produce the necessary coinbase commitment for a block (modifies the hash, don't call for mined blocks). */
 417 std::vector<unsigned char> GenerateCoinbaseCommitment(CBlock& block, const CBlockIndex* pindexPrev, const Consensus::Params& consensusParams);
 418
 419 /** RAII wrapper for VerifyDB: Verify consistency of the block and coin databases */
 420 class CVerifyDB {
 421 public:
 422     CVerifyDB();
 423     ~CVerifyDB();
 424     bool VerifyDB(const CChainParams& chainparams, CCoinsView *coinsview, int nCheckLevel, int nCheckDepth);
 425 };
 426
 427 /** Replay blocks that aren't fully applied to the database. */
 428 bool ReplayBlocks(const CChainParams& params, CCoinsView* view);
 429
 430 /** Find the last common block between the parameter chain and a locator. */
 431 CBlockIndex* FindForkInGlobalIndex(const CChain& chain, const CBlockLocator& locator);
 432
 433 /** Mark a block as precious and reorganize. */
 434 bool PreciousBlock(CValidationState& state, const CChainParams& params, CBlockIndex *pindex);
 435
 436 /** Mark a block as invalid. */
 437 bool InvalidateBlock(CValidationState& state, const CChainParams& chainparams, CBlockIndex *pindex);
 438
 439 /** Remove invalidity status from a block and its descendants. */
 440 bool ResetBlockFailureFlags(CBlockIndex *pindex);
 441
 442 /** The currently-connected chain of blocks (protected by cs_main). */
 443 extern CChain chainActive;
 444
 445 /** Global variable that points to the coins database (protected by cs_main) */
 446 extern CCoinsViewDB *pcoinsdbview;
 447
 448 /** Global variable that points to the active CCoinsView (protected by cs_main) */
 449 extern CCoinsViewCache *pcoinsTip;
 450
 451 /** Global variable that points to the active block tree (protected by cs_main) */
 452 extern CBlockTreeDB *pblocktree;
 453
 454 /**
 455  * Return the spend height, which is one more than the inputs.GetBestBlock().
 456  * While checking, GetBestBlock() refers to the parent block. (protected by cs_main)
 457  * This is also true for mempool checks.
 458  */
 459 int GetSpendHeight(const CCoinsViewCache& inputs);
 460
 461 extern VersionBitsCache versionbitscache;
 462
 463 /**
 464  * Determine what nVersion a new block should use.
 465  */
 466 int32_t ComputeBlockVersion(const CBlockIndex* pindexPrev, const Consensus::Params& params);
 467
 468 /** Reject codes greater or equal to this can be returned by AcceptToMemPool
 469  * for transactions, to signal internal conditions. They cannot and should not
 470  * be sent over the P2P network.
 471  */
 472 static const unsigned int REJECT_INTERNAL = 0x100;
 473 /** Too high fee. Can not be triggered by P2P transactions */
 474 static const unsigned int REJECT_HIGHFEE = 0x100;
 475
 476 /** Get block file info entry for one block file */
 477 CBlockFileInfo* GetBlockFileInfo(size_t n);
 478
 479 /** Dump the mempool to disk. */
 480 bool DumpMempool();
 481
 482 /** Load the mempool from disk. */
 483 bool LoadMempool();
 484
 485 #endif // BITCOIN_VALIDATION_H