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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or
#if defined(HAVE_CONFIG_H)
#include "config/bitcoin-config.h"
#include "amount.h"
#include "chain.h"
#include "chainparams.h"
#include "coins.h"
#include "primitives/block.h"
#include "primitives/transaction.h"
#include "net.h"
#include "script/script.h"
#include "script/sigcache.h"
#include "script/standard.h"
#include "sync.h"
#include "tinyformat.h"
#include "txmempool.h"
#include "uint256.h"
#include <algorithm>
#include <exception>
#include <map>
#include <set>
#include <stdint.h>
#include <string>
#include <utility>
#include <vector>
#include <boost/unordered_map.hpp>
class CBlockIndex;
class CBlockTreeDB;
class CBloomFilter;
class CInv;
class CScriptCheck;
class CValidationInterface;
class CValidationState;
struct CNodeStateStats;
/** Default for -blockmaxsize and -blockminsize, which control the range of sizes the mining code will create **/
static const unsigned int DEFAULT_BLOCK_MAX_SIZE = 750000;
static const unsigned int DEFAULT_BLOCK_MIN_SIZE = 0;
/** Default for -blockprioritysize, maximum space for zero/low-fee transactions **/
static const unsigned int DEFAULT_BLOCK_PRIORITY_SIZE = 50000;
/** The maximum size for transactions we're willing to relay/mine */
static const unsigned int MAX_STANDARD_TX_SIZE = 100000;
/** The maximum allowed number of signature check operations in a block (network rule) */
static const unsigned int MAX_BLOCK_SIGOPS = MAX_BLOCK_SIZE/50;
/** Maximum number of signature check operations in an IsStandard() P2SH script */
static const unsigned int MAX_P2SH_SIGOPS = 15;
/** The maximum number of sigops we're willing to relay/mine in a single tx */
static const unsigned int MAX_STANDARD_TX_SIGOPS = MAX_BLOCK_SIGOPS/5;
/** Default for -maxorphantx, maximum number of orphan transactions kept in memory */
static const unsigned int DEFAULT_MAX_ORPHAN_TRANSACTIONS = 100;
/** The maximum size of a blk?????.dat file (since 0.8) */
static const unsigned int MAX_BLOCKFILE_SIZE = 0x8000000; // 128 MiB
/** The pre-allocation chunk size for blk?????.dat files (since 0.8) */
static const unsigned int BLOCKFILE_CHUNK_SIZE = 0x1000000; // 16 MiB
/** The pre-allocation chunk size for rev?????.dat files (since 0.8) */
static const unsigned int UNDOFILE_CHUNK_SIZE = 0x100000; // 1 MiB
/** Coinbase transaction outputs can only be spent after this number of new blocks (network rule) */
static const int COINBASE_MATURITY = 100;
/** Threshold for nLockTime: below this value it is interpreted as block number, otherwise as UNIX timestamp. */
static const unsigned int LOCKTIME_THRESHOLD = 500000000; // Tue Nov 5 00:53:20 1985 UTC
/** Maximum number of script-checking threads allowed */
static const int MAX_SCRIPTCHECK_THREADS = 16;
/** -par default (number of script-checking threads, 0 = auto) */
/** Number of blocks that can be requested at any given time from a single peer. */
static const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 16;
/** Timeout in seconds during which a peer must stall block download progress before being disconnected. */
static const unsigned int BLOCK_STALLING_TIMEOUT = 2;
/** Number of headers sent in one getheaders result. We rely on the assumption that if a peer sends
* less than this number, we reached their tip. Changing this value is a protocol upgrade. */
static const unsigned int MAX_HEADERS_RESULTS = 2000;
/** Size of the "block download window": how far ahead of our current height do we fetch?
* Larger windows tolerate larger download speed differences between peer, but increase the potential
* degree of disordering of blocks on disk (which make reindexing and in the future perhaps pruning
* harder). We'll probably want to make this a per-peer adaptive value at some point. */
static const unsigned int BLOCK_DOWNLOAD_WINDOW = 1024;
/** Time to wait (in seconds) between writing blockchain state to disk. */
static const unsigned int DATABASE_WRITE_INTERVAL = 3600;
/** Maximum length of reject messages. */
static const unsigned int MAX_REJECT_MESSAGE_LENGTH = 111;
/** "reject" message codes */
static const unsigned char REJECT_MALFORMED = 0x01;
static const unsigned char REJECT_INVALID = 0x10;
static const unsigned char REJECT_OBSOLETE = 0x11;
static const unsigned char REJECT_DUPLICATE = 0x12;
static const unsigned char REJECT_NONSTANDARD = 0x40;
static const unsigned char REJECT_DUST = 0x41;
static const unsigned char REJECT_INSUFFICIENTFEE = 0x42;
static const unsigned char REJECT_CHECKPOINT = 0x43;
struct BlockHasher
size_t operator()(const uint256& hash) const { return hash.GetCheapHash(); }
extern CScript COINBASE_FLAGS;
extern CCriticalSection cs_main;
extern CTxMemPool mempool;
typedef boost::unordered_map<uint256, CBlockIndex*, BlockHasher> BlockMap;
extern BlockMap mapBlockIndex;
extern uint64_t nLastBlockTx;
extern uint64_t nLastBlockSize;
extern const std::string strMessageMagic;
extern CWaitableCriticalSection csBestBlock;
extern CConditionVariable cvBlockChange;
extern bool fImporting;
extern bool fReindex;
extern int nScriptCheckThreads;
extern bool fTxIndex;
extern bool fIsBareMultisigStd;
extern bool fCheckBlockIndex;
extern unsigned int nCoinCacheSize;
extern CFeeRate minRelayTxFee;
/** Best header we've seen so far (used for getheaders queries' starting points). */
extern CBlockIndex *pindexBestHeader;
/** Minimum disk space required - used in CheckDiskSpace() */
static const uint64_t nMinDiskSpace = 52428800;
/** Pruning-related variables and constants */
/** True if any block files have ever been pruned. */
extern bool fHavePruned;
/** True if we're running in -prune mode. */
extern bool fPruneMode;
/** Number of MiB of block files that we're trying to stay below. */
extern uint64_t nPruneTarget;
/** Block files containing a block-height within MIN_BLOCKS_TO_KEEP of chainActive.Tip() will not be pruned. */
static const signed int MIN_BLOCKS_TO_KEEP = 288;
// Require that user allocate at least 550MB 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 > than 550MB will make it likely we can respect the target.
static const signed int MIN_DISK_SPACE_FOR_BLOCK_FILES = 550 * 1024 * 1024;
/** Register with a network node to receive its signals */
void RegisterNodeSignals(CNodeSignals& nodeSignals);
/** Unregister a network node */
void UnregisterNodeSignals(CNodeSignals& nodeSignals);
* Process an incoming block. This only returns after the best known valid
* block is made active. Note that it does not, however, guarantee that the
* specific block passed to it has been checked for validity!
* @param[out] state This may be set to an Error state if any error occurred processing it, including during validation/connection/etc of otherwise unrelated blocks during reorganisation; or it may be set to an Invalid state if pblock is itself invalid (but this is not guaranteed even when the block is checked). If you want to *possibly* get feedback on whether pblock is valid, you must also install a CValidationInterface (see validationinterface.h) - this will have its BlockChecked method called whenever *any* block completes validation.
* @param[in] pfrom The node which we are receiving the block from; it is added to mapBlockSource and may be penalised if the block is invalid.
* @param[in] pblock The block we want to process.
* @param[out] dbp If pblock is stored to disk (or already there), this will be set to its location.
* @return True if state.IsValid()
bool ProcessNewBlock(CValidationState &state, CNode* pfrom, CBlock* pblock, CDiskBlockPos *dbp = NULL);
/** Check whether enough disk space is available for an incoming block */
bool CheckDiskSpace(uint64_t nAdditionalBytes = 0);
/** Open a block file (blk?????.dat) */
FILE* OpenBlockFile(const CDiskBlockPos &pos, bool fReadOnly = false);
/** Open an undo file (rev?????.dat) */
FILE* OpenUndoFile(const CDiskBlockPos &pos, bool fReadOnly = false);
/** Translation to a filesystem path */
boost::filesystem::path GetBlockPosFilename(const CDiskBlockPos &pos, const char *prefix);
/** Import blocks from an external file */
bool LoadExternalBlockFile(FILE* fileIn, CDiskBlockPos *dbp = NULL);
/** Initialize a new block tree database + block data on disk */
bool InitBlockIndex();
/** Load the block tree and coins database from disk */
bool LoadBlockIndex();
/** Unload database information */
void UnloadBlockIndex();
/** Process protocol messages received from a given node */
bool ProcessMessages(CNode* pfrom);
* Send queued protocol messages to be sent to a give node.
* @param[in] pto The node which we are sending messages to.
* @param[in] fSendTrickle When true send the trickled data, otherwise trickle the data until true.
bool SendMessages(CNode* pto, bool fSendTrickle);
/** Run an instance of the script checking thread */
void ThreadScriptCheck();
/** Check whether we are doing an initial block download (synchronizing from disk or network) */
bool IsInitialBlockDownload();
/** Format a string that describes several potential problems detected by the core */
std::string GetWarnings(std::string strFor);
/** Retrieve a transaction (from memory pool, or from disk, if possible) */
bool GetTransaction(const uint256 &hash, CTransaction &tx, uint256 &hashBlock, bool fAllowSlow = false);
/** Find the best known block, and make it the tip of the block chain */
bool ActivateBestChain(CValidationState &state, CBlock *pblock = NULL);
CAmount GetBlockValue(int nHeight, const CAmount& nFees);
* Prune block and undo files (blk???.dat and undo???.dat) so that the disk space used is less than a user-defined target.
* The user sets the target (in MB) on the command line or in config file. This will be run on startup and whenever new
* space is allocated in a block or undo file, staying below the target. Changing back to unpruned requires a reindex
* (which in this case means the blockchain must be re-downloaded.)
* Pruning functions are called from FlushStateToDisk when the global fCheckForPruning flag has been set.
* Block and undo files are deleted in lock-step (when blk00003.dat is deleted, so is rev00003.dat.)
* Pruning cannot take place until the longest chain is at least a certain length (100000 on mainnet, 1000 on testnet, 10 on regtest).
* Pruning will never delete a block within a defined distance (currently 288) from the active chain's tip.
* The block index is updated by unsetting HAVE_DATA and HAVE_UNDO for any blocks that were stored in the deleted files.
* A db flag records the fact that at least some block files have been pruned.
* @param[out] setFilesToPrune The set of file indices that can be unlinked will be returned
void FindFilesToPrune(std::set<int>& setFilesToPrune);
* Actually unlink the specified files
void UnlinkPrunedFiles(std::set<int>& setFilesToPrune);
/** Create a new block index entry for a given block hash */
CBlockIndex * InsertBlockIndex(uint256 hash);
/** Abort with a message */
bool AbortNode(const std::string &msg, const std::string &userMessage="");
/** Get statistics from node state */
bool GetNodeStateStats(NodeId nodeid, CNodeStateStats &stats);
/** Increase a node's misbehavior score. */
void Misbehaving(NodeId nodeid, int howmuch);
/** Flush all state, indexes and buffers to disk. */
void FlushStateToDisk();
/** Prune block files and flush state to disk. */
void PruneAndFlush();
/** (try to) add transaction to memory pool **/
bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransaction &tx, bool fLimitFree,
bool* pfMissingInputs, bool fRejectAbsurdFee=false);
struct CNodeStateStats {
int nMisbehavior;
int nSyncHeight;
int nCommonHeight;
std::vector<int> vHeightInFlight;
struct CDiskTxPos : public CDiskBlockPos
unsigned int nTxOffset; // after header
template <typename Stream, typename Operation>
inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
CDiskTxPos(const CDiskBlockPos &blockIn, unsigned int nTxOffsetIn) : CDiskBlockPos(blockIn.nFile, blockIn.nPos), nTxOffset(nTxOffsetIn) {
CDiskTxPos() {
void SetNull() {
nTxOffset = 0;
CAmount GetMinRelayFee(const CTransaction& tx, unsigned int nBytes, bool fAllowFree);
* Check transaction inputs, and make sure any
* pay-to-script-hash transactions are evaluating IsStandard scripts
* Why bother? To avoid denial-of-service attacks; an attacker
* can submit a standard HASH... OP_EQUAL transaction,
* which will get accepted into blocks. The redemption
* script can be anything; an attacker could use a very
* expensive-to-check-upon-redemption script like:
* DUP CHECKSIG DROP ... repeated 100 times... OP_1
* Check for standard transaction types
* @param[in] mapInputs Map of previous transactions that have outputs we're spending
* @return True if all inputs (scriptSigs) use only standard transaction forms
bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs);
* Count ECDSA signature operations the old-fashioned (pre-0.6) way
* @return number of sigops this transaction's outputs will produce when spent
* @see CTransaction::FetchInputs
unsigned int GetLegacySigOpCount(const CTransaction& tx);
* Count ECDSA signature operations in pay-to-script-hash inputs.
* @param[in] mapInputs Map of previous transactions that have outputs we're spending
* @return maximum number of sigops required to validate this transaction's inputs
* @see CTransaction::FetchInputs
unsigned int GetP2SHSigOpCount(const CTransaction& tx, const CCoinsViewCache& mapInputs);
* Check whether all inputs of this transaction are valid (no double spends, scripts & sigs, amounts)
* This does not modify the UTXO set. If pvChecks is not NULL, script checks are pushed onto it
* instead of being performed inline.
bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &view, bool fScriptChecks,
unsigned int flags, bool cacheStore, std::vector<CScriptCheck> *pvChecks = NULL);
/** Apply the effects of this transaction on the UTXO set represented by view */
void UpdateCoins(const CTransaction& tx, CValidationState &state, CCoinsViewCache &inputs, int nHeight);
/** Context-independent validity checks */
bool CheckTransaction(const CTransaction& tx, CValidationState& state);
/** Check for standard transaction types
* @return True if all outputs (scriptPubKeys) use only standard transaction forms
bool IsStandardTx(const CTransaction& tx, std::string& reason);
bool IsFinalTx(const CTransaction &tx, int nBlockHeight = 0, int64_t nBlockTime = 0);
* Closure representing one script verification
* Note that this stores references to the spending transaction
class CScriptCheck
CScript scriptPubKey;
const CTransaction *ptxTo;
unsigned int nIn;
unsigned int nFlags;
bool cacheStore;
ScriptError error;
CScriptCheck(): ptxTo(0), nIn(0), nFlags(0), cacheStore(false), error(SCRIPT_ERR_UNKNOWN_ERROR) {}
CScriptCheck(const CCoins& txFromIn, const CTransaction& txToIn, unsigned int nInIn, unsigned int nFlagsIn, bool cacheIn) :
ptxTo(&txToIn), nIn(nInIn), nFlags(nFlagsIn), cacheStore(cacheIn), error(SCRIPT_ERR_UNKNOWN_ERROR) { }
bool operator()();
void swap(CScriptCheck &check) {
std::swap(ptxTo, check.ptxTo);
std::swap(nIn, check.nIn);
std::swap(nFlags, check.nFlags);
std::swap(cacheStore, check.cacheStore);
std::swap(error, check.error);
ScriptError GetScriptError() const { return error; }
/** Functions for disk access for blocks */
bool WriteBlockToDisk(CBlock& block, CDiskBlockPos& pos);
bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos);
bool ReadBlockFromDisk(CBlock& block, const CBlockIndex* pindex);
/** Functions for validating blocks and updating the block tree */
/** Undo the effects of this block (with given index) on the UTXO set represented by coins.
* In case pfClean is provided, operation will try to be tolerant about errors, and *pfClean
* will be true if no problems were found. Otherwise, the return value will be false in case
* of problems. Note that in any case, coins may be modified. */
bool DisconnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, CCoinsViewCache& coins, bool* pfClean = NULL);
/** Apply the effects of this block (with given index) on the UTXO set represented by coins */
bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pindex, CCoinsViewCache& coins, bool fJustCheck = false);
/** Context-independent validity checks */
bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, bool fCheckPOW = true);
bool CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW = true, bool fCheckMerkleRoot = true);
/** Context-dependent validity checks */
bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& state, CBlockIndex *pindexPrev);
bool ContextualCheckBlock(const CBlock& block, CValidationState& state, CBlockIndex *pindexPrev);
/** Check a block is completely valid from start to finish (only works on top of our current best block, with cs_main held) */
bool TestBlockValidity(CValidationState &state, const CBlock& block, CBlockIndex *pindexPrev, bool fCheckPOW = true, bool fCheckMerkleRoot = true);
/** Store block on disk. If dbp is provided, the file is known to already reside on disk */
bool AcceptBlock(CBlock& block, CValidationState& state, CBlockIndex **pindex, CDiskBlockPos* dbp = NULL);
bool AcceptBlockHeader(const CBlockHeader& block, CValidationState& state, CBlockIndex **ppindex= NULL);
class CBlockFileInfo
unsigned int nBlocks; //! number of blocks stored in file
unsigned int nSize; //! number of used bytes of block file
unsigned int nUndoSize; //! number of used bytes in the undo file
unsigned int nHeightFirst; //! lowest height of block in file
unsigned int nHeightLast; //! highest height of block in file
uint64_t nTimeFirst; //! earliest time of block in file
uint64_t nTimeLast; //! latest time of block in file
template <typename Stream, typename Operation>
inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
void SetNull() {
nBlocks = 0;
nSize = 0;
nUndoSize = 0;
nHeightFirst = 0;
nHeightLast = 0;
nTimeFirst = 0;
nTimeLast = 0;
CBlockFileInfo() {
std::string ToString() const;
/** update statistics (does not update nSize) */
void AddBlock(unsigned int nHeightIn, uint64_t nTimeIn) {
if (nBlocks==0 || nHeightFirst > nHeightIn)
nHeightFirst = nHeightIn;
if (nBlocks==0 || nTimeFirst > nTimeIn)
nTimeFirst = nTimeIn;
if (nHeightIn > nHeightLast)
nHeightLast = nHeightIn;
if (nTimeIn > nTimeLast)
nTimeLast = nTimeIn;
/** Capture information about block/transaction validation */
class CValidationState {
enum mode_state {
MODE_VALID, //! everything ok
MODE_INVALID, //! network rule violation (DoS value may be set)
MODE_ERROR, //! run-time error
} mode;
int nDoS;
std::string strRejectReason;
unsigned char chRejectCode;
bool corruptionPossible;
CValidationState() : mode(MODE_VALID), nDoS(0), chRejectCode(0), corruptionPossible(false) {}
bool DoS(int level, bool ret = false,
unsigned char chRejectCodeIn=0, std::string strRejectReasonIn="",
bool corruptionIn=false) {
chRejectCode = chRejectCodeIn;
strRejectReason = strRejectReasonIn;
corruptionPossible = corruptionIn;
if (mode == MODE_ERROR)
return ret;
nDoS += level;
return ret;
bool Invalid(bool ret = false,
unsigned char _chRejectCode=0, std::string _strRejectReason="") {
return DoS(0, ret, _chRejectCode, _strRejectReason);
bool Error(std::string strRejectReasonIn="") {
if (mode == MODE_VALID)
strRejectReason = strRejectReasonIn;
mode = MODE_ERROR;
return false;
bool Abort(const std::string &msg) {
return Error(msg);
bool IsValid() const {
return mode == MODE_VALID;
bool IsInvalid() const {
return mode == MODE_INVALID;
bool IsError() const {
return mode == MODE_ERROR;
bool IsInvalid(int &nDoSOut) const {
if (IsInvalid()) {
nDoSOut = nDoS;
return true;
return false;
bool CorruptionPossible() const {
return corruptionPossible;
unsigned char GetRejectCode() const { return chRejectCode; }
std::string GetRejectReason() const { return strRejectReason; }
/** RAII wrapper for VerifyDB: Verify consistency of the block and coin databases */
class CVerifyDB {
bool VerifyDB(CCoinsView *coinsview, int nCheckLevel, int nCheckDepth);
/** Find the last common block between the parameter chain and a locator. */
CBlockIndex* FindForkInGlobalIndex(const CChain& chain, const CBlockLocator& locator);
/** Mark a block as invalid. */
bool InvalidateBlock(CValidationState& state, CBlockIndex *pindex);
/** Remove invalidity status from a block and its descendants. */
bool ReconsiderBlock(CValidationState& state, CBlockIndex *pindex);
/** The currently-connected chain of blocks. */
extern CChain chainActive;
/** Global variable that points to the active CCoinsView (protected by cs_main) */
extern CCoinsViewCache *pcoinsTip;
/** Global variable that points to the active block tree (protected by cs_main) */
extern CBlockTreeDB *pblocktree;
#endif // BITCOIN_MAIN_H