// Copyright (c) 2009-2010 Satoshi Nakamoto // Copyright (c) 2009-2021 The Bitcoin Core developers // Distributed under the MIT software license, see the accompanying // file COPYING or http://www.opensource.org/licenses/mit-license.php. #include <validation.h> #include <kernel/coinstats.h> #include <kernel/mempool_persist.h> #include <arith_uint256.h> #include <chain.h> #include <chainparams.h> #include <checkqueue.h> #include <consensus/amount.h> #include <consensus/consensus.h> #include <consensus/merkle.h> #include <consensus/tx_check.h> #include <consensus/tx_verify.h> #include <consensus/validation.h> #include <cuckoocache.h> #include <flatfile.h> #include <fs.h> #include <hash.h> #include <logging.h> #include <logging/timer.h> #include <node/blockstorage.h> #include <node/interface_ui.h> #include <node/utxo_snapshot.h> #include <policy/policy.h> #include <policy/rbf.h> #include <policy/settings.h> #include <pow.h> #include <primitives/block.h> #include <primitives/transaction.h> #include <random.h> #include <reverse_iterator.h> #include <script/script.h> #include <script/sigcache.h> #include <shutdown.h> #include <signet.h> #include <tinyformat.h> #include <txdb.h> #include <txmempool.h> #include <uint256.h> #include <undo.h> #include <util/check.h> // For NDEBUG compile time check #include <util/hasher.h> #include <util/moneystr.h> #include <util/rbf.h> #include <util/strencodings.h> #include <util/system.h> #include <util/time.h> #include <util/trace.h> #include <util/translation.h> #include <validationinterface.h> #include <warnings.h> #include <algorithm> #include <cassert> #include <chrono> #include <deque> #include <numeric> #include <optional> #include <string> using kernel::CCoinsStats; using kernel::CoinStatsHashType; using kernel::ComputeUTXOStats; using kernel::LoadMempool; using fsbridge::FopenFn; using node::BlockManager; using node::BlockMap; using node::CBlockIndexHeightOnlyComparator; using node::CBlockIndexWorkComparator; using node::fImporting; using node::fPruneMode; using node::fReindex; using node::ReadBlockFromDisk; using node::SnapshotMetadata; using node::UndoReadFromDisk; using node::UnlinkPrunedFiles; #define MICRO 0.000001 #define MILLI 0.001 /** Maximum kilobytes for transactions to store for processing during reorg */ static const unsigned int MAX_DISCONNECTED_TX_POOL_SIZE = 20000; /** Time to wait between writing blocks/block index to disk. */ static constexpr std::chrono::hours DATABASE_WRITE_INTERVAL{1}; /** Time to wait between flushing chainstate to disk. */ static constexpr std::chrono::hours DATABASE_FLUSH_INTERVAL{24}; /** Maximum age of our tip for us to be considered current for fee estimation */ static constexpr std::chrono::hours MAX_FEE_ESTIMATION_TIP_AGE{3}; const std::vector<std::string> CHECKLEVEL_DOC { "level 0 reads the blocks from disk", "level 1 verifies block validity", "level 2 verifies undo data", "level 3 checks disconnection of tip blocks", "level 4 tries to reconnect the blocks", "each level includes the checks of the previous levels", }; /** The number of blocks to keep below the deepest prune lock. * There is nothing special about this number. It is higher than what we * expect to see in regular mainnet reorgs, but not so high that it would * noticeably interfere with the pruning mechanism. * */ static constexpr int PRUNE_LOCK_BUFFER{10}; /** * Mutex to guard access to validation specific variables, such as reading * or changing the chainstate. * * This may also need to be locked when updating the transaction pool, e.g. on * AcceptToMemoryPool. See CTxMemPool::cs comment for details. * * The transaction pool has a separate lock to allow reading from it and the * chainstate at the same time. */ RecursiveMutex cs_main; GlobalMutex g_best_block_mutex; std::condition_variable g_best_block_cv; uint256 g_best_block; bool g_parallel_script_checks{false}; bool fCheckBlockIndex = false; bool fCheckpointsEnabled = DEFAULT_CHECKPOINTS_ENABLED; int64_t nMaxTipAge = DEFAULT_MAX_TIP_AGE; uint256 hashAssumeValid; arith_uint256 nMinimumChainWork; const CBlockIndex* Chainstate::FindForkInGlobalIndex(const CBlockLocator& locator) const { AssertLockHeld(cs_main); // Find the latest block common to locator and chain - we expect that // locator.vHave is sorted descending by height. for (const uint256& hash : locator.vHave) { const CBlockIndex* pindex{m_blockman.LookupBlockIndex(hash)}; if (pindex) { if (m_chain.Contains(pindex)) { return pindex; } if (pindex->GetAncestor(m_chain.Height()) == m_chain.Tip()) { return m_chain.Tip(); } } } return m_chain.Genesis(); } bool CheckInputScripts(const CTransaction& tx, TxValidationState& state, const CCoinsViewCache& inputs, unsigned int flags, bool cacheSigStore, bool cacheFullScriptStore, PrecomputedTransactionData& txdata, std::vector<CScriptCheck>* pvChecks = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs_main); bool CheckFinalTxAtTip(const CBlockIndex& active_chain_tip, const CTransaction& tx) { AssertLockHeld(cs_main); // CheckFinalTxAtTip() uses active_chain_tip.Height()+1 to evaluate // nLockTime because when IsFinalTx() is called within // AcceptBlock(), the height of the block *being* // evaluated is what is used. Thus if we want to know if a // transaction can be part of the *next* block, we need to call // IsFinalTx() with one more than active_chain_tip.Height(). const int nBlockHeight = active_chain_tip.nHeight + 1; // BIP113 requires that time-locked transactions have nLockTime set to // less than the median time of the previous block they're contained in. // When the next block is created its previous block will be the current // chain tip, so we use that to calculate the median time passed to // IsFinalTx(). const int64_t nBlockTime{active_chain_tip.GetMedianTimePast()}; return IsFinalTx(tx, nBlockHeight, nBlockTime); } bool CheckSequenceLocksAtTip(CBlockIndex* tip, const CCoinsView& coins_view, const CTransaction& tx, LockPoints* lp, bool useExistingLockPoints) { assert(tip != nullptr); CBlockIndex index; index.pprev = tip; // CheckSequenceLocksAtTip() uses active_chainstate.m_chain.Height()+1 to evaluate // height based locks because when SequenceLocks() is called within // ConnectBlock(), the height of the block *being* // evaluated is what is used. // Thus if we want to know if a transaction can be part of the // *next* block, we need to use one more than active_chainstate.m_chain.Height() index.nHeight = tip->nHeight + 1; std::pair<int, int64_t> lockPair; if (useExistingLockPoints) { assert(lp); lockPair.first = lp->height; lockPair.second = lp->time; } else { std::vector<int> prevheights; prevheights.resize(tx.vin.size()); for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) { const CTxIn& txin = tx.vin[txinIndex]; Coin coin; if (!coins_view.GetCoin(txin.prevout, coin)) { return error("%s: Missing input", __func__); } if (coin.nHeight == MEMPOOL_HEIGHT) { // Assume all mempool transaction confirm in the next block prevheights[txinIndex] = tip->nHeight + 1; } else { prevheights[txinIndex] = coin.nHeight; } } lockPair = CalculateSequenceLocks(tx, STANDARD_LOCKTIME_VERIFY_FLAGS, prevheights, index); if (lp) { lp->height = lockPair.first; lp->time = lockPair.second; // Also store the hash of the block with the highest height of // all the blocks which have sequence locked prevouts. // This hash needs to still be on the chain // for these LockPoint calculations to be valid // Note: It is impossible to correctly calculate a maxInputBlock // if any of the sequence locked inputs depend on unconfirmed txs, // except in the special case where the relative lock time/height // is 0, which is equivalent to no sequence lock. Since we assume // input height of tip+1 for mempool txs and test the resulting // lockPair from CalculateSequenceLocks against tip+1. We know // EvaluateSequenceLocks will fail if there was a non-zero sequence // lock on a mempool input, so we can use the return value of // CheckSequenceLocksAtTip to indicate the LockPoints validity int maxInputHeight = 0; for (const int height : prevheights) { // Can ignore mempool inputs since we'll fail if they had non-zero locks if (height != tip->nHeight+1) { maxInputHeight = std::max(maxInputHeight, height); } } // tip->GetAncestor(maxInputHeight) should never return a nullptr // because maxInputHeight is always less than the tip height. // It would, however, be a bad bug to continue execution, since a // LockPoints object with the maxInputBlock member set to nullptr // signifies no relative lock time. lp->maxInputBlock = Assert(tip->GetAncestor(maxInputHeight)); } } return EvaluateSequenceLocks(index, lockPair); } // Returns the script flags which should be checked for a given block static unsigned int GetBlockScriptFlags(const CBlockIndex& block_index, const ChainstateManager& chainman); static void LimitMempoolSize(CTxMemPool& pool, CCoinsViewCache& coins_cache) EXCLUSIVE_LOCKS_REQUIRED(::cs_main, pool.cs) { AssertLockHeld(::cs_main); AssertLockHeld(pool.cs); int expired = pool.Expire(GetTime<std::chrono::seconds>() - pool.m_expiry); if (expired != 0) { LogPrint(BCLog::MEMPOOL, "Expired %i transactions from the memory pool\n", expired); } std::vector<COutPoint> vNoSpendsRemaining; pool.TrimToSize(pool.m_max_size_bytes, &vNoSpendsRemaining); for (const COutPoint& removed : vNoSpendsRemaining) coins_cache.Uncache(removed); } static bool IsCurrentForFeeEstimation(Chainstate& active_chainstate) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { AssertLockHeld(cs_main); if (active_chainstate.IsInitialBlockDownload()) return false; if (active_chainstate.m_chain.Tip()->GetBlockTime() < count_seconds(GetTime<std::chrono::seconds>() - MAX_FEE_ESTIMATION_TIP_AGE)) return false; if (active_chainstate.m_chain.Height() < active_chainstate.m_chainman.m_best_header->nHeight - 1) { return false; } return true; } void Chainstate::MaybeUpdateMempoolForReorg( DisconnectedBlockTransactions& disconnectpool, bool fAddToMempool) { if (!m_mempool) return; AssertLockHeld(cs_main); AssertLockHeld(m_mempool->cs); std::vector<uint256> vHashUpdate; // disconnectpool's insertion_order index sorts the entries from // oldest to newest, but the oldest entry will be the last tx from the // latest mined block that was disconnected. // Iterate disconnectpool in reverse, so that we add transactions // back to the mempool starting with the earliest transaction that had // been previously seen in a block. auto it = disconnectpool.queuedTx.get<insertion_order>().rbegin(); while (it != disconnectpool.queuedTx.get<insertion_order>().rend()) { // ignore validation errors in resurrected transactions if (!fAddToMempool || (*it)->IsCoinBase() || AcceptToMemoryPool(*this, *it, GetTime(), /*bypass_limits=*/true, /*test_accept=*/false).m_result_type != MempoolAcceptResult::ResultType::VALID) { // If the transaction doesn't make it in to the mempool, remove any // transactions that depend on it (which would now be orphans). m_mempool->removeRecursive(**it, MemPoolRemovalReason::REORG); } else if (m_mempool->exists(GenTxid::Txid((*it)->GetHash()))) { vHashUpdate.push_back((*it)->GetHash()); } ++it; } disconnectpool.queuedTx.clear(); // AcceptToMemoryPool/addUnchecked all assume that new mempool entries have // no in-mempool children, which is generally not true when adding // previously-confirmed transactions back to the mempool. // UpdateTransactionsFromBlock finds descendants of any transactions in // the disconnectpool that were added back and cleans up the mempool state. m_mempool->UpdateTransactionsFromBlock(vHashUpdate); // Predicate to use for filtering transactions in removeForReorg. // Checks whether the transaction is still final and, if it spends a coinbase output, mature. // Also updates valid entries' cached LockPoints if needed. // If false, the tx is still valid and its lockpoints are updated. // If true, the tx would be invalid in the next block; remove this entry and all of its descendants. const auto filter_final_and_mature = [this](CTxMemPool::txiter it) EXCLUSIVE_LOCKS_REQUIRED(m_mempool->cs, ::cs_main) { AssertLockHeld(m_mempool->cs); AssertLockHeld(::cs_main); const CTransaction& tx = it->GetTx(); // The transaction must be final. if (!CheckFinalTxAtTip(*Assert(m_chain.Tip()), tx)) return true; LockPoints lp = it->GetLockPoints(); const bool validLP{TestLockPointValidity(m_chain, lp)}; CCoinsViewMemPool view_mempool(&CoinsTip(), *m_mempool); // CheckSequenceLocksAtTip checks if the transaction will be final in the next block to be // created on top of the new chain. We use useExistingLockPoints=false so that, instead of // using the information in lp (which might now refer to a block that no longer exists in // the chain), it will update lp to contain LockPoints relevant to the new chain. if (!CheckSequenceLocksAtTip(m_chain.Tip(), view_mempool, tx, &lp, validLP)) { // If CheckSequenceLocksAtTip fails, remove the tx and don't depend on the LockPoints. return true; } else if (!validLP) { // If CheckSequenceLocksAtTip succeeded, it also updated the LockPoints. // Now update the mempool entry lockpoints as well. m_mempool->mapTx.modify(it, [&lp](CTxMemPoolEntry& e) { e.UpdateLockPoints(lp); }); } // If the transaction spends any coinbase outputs, it must be mature. if (it->GetSpendsCoinbase()) { for (const CTxIn& txin : tx.vin) { auto it2 = m_mempool->mapTx.find(txin.prevout.hash); if (it2 != m_mempool->mapTx.end()) continue; const Coin& coin{CoinsTip().AccessCoin(txin.prevout)}; assert(!coin.IsSpent()); const auto mempool_spend_height{m_chain.Tip()->nHeight + 1}; if (coin.IsCoinBase() && mempool_spend_height - coin.nHeight < COINBASE_MATURITY) { return true; } } } // Transaction is still valid and cached LockPoints are updated. return false; }; // We also need to remove any now-immature transactions m_mempool->removeForReorg(m_chain, filter_final_and_mature); // Re-limit mempool size, in case we added any transactions LimitMempoolSize(*m_mempool, this->CoinsTip()); } /** * Checks to avoid mempool polluting consensus critical paths since cached * signature and script validity results will be reused if we validate this * transaction again during block validation. * */ static bool CheckInputsFromMempoolAndCache(const CTransaction& tx, TxValidationState& state, const CCoinsViewCache& view, const CTxMemPool& pool, unsigned int flags, PrecomputedTransactionData& txdata, CCoinsViewCache& coins_tip) EXCLUSIVE_LOCKS_REQUIRED(cs_main, pool.cs) { AssertLockHeld(cs_main); AssertLockHeld(pool.cs); assert(!tx.IsCoinBase()); for (const CTxIn& txin : tx.vin) { const Coin& coin = view.AccessCoin(txin.prevout); // This coin was checked in PreChecks and MemPoolAccept // has been holding cs_main since then. Assume(!coin.IsSpent()); if (coin.IsSpent()) return false; // If the Coin is available, there are 2 possibilities: // it is available in our current ChainstateActive UTXO set, // or it's a UTXO provided by a transaction in our mempool. // Ensure the scriptPubKeys in Coins from CoinsView are correct. const CTransactionRef& txFrom = pool.get(txin.prevout.hash); if (txFrom) { assert(txFrom->GetHash() == txin.prevout.hash); assert(txFrom->vout.size() > txin.prevout.n); assert(txFrom->vout[txin.prevout.n] == coin.out); } else { const Coin& coinFromUTXOSet = coins_tip.AccessCoin(txin.prevout); assert(!coinFromUTXOSet.IsSpent()); assert(coinFromUTXOSet.out == coin.out); } } // Call CheckInputScripts() to cache signature and script validity against current tip consensus rules. return CheckInputScripts(tx, state, view, flags, /* cacheSigStore= */ true, /* cacheFullScriptStore= */ true, txdata); } namespace { class MemPoolAccept { public: explicit MemPoolAccept(CTxMemPool& mempool, Chainstate& active_chainstate) : m_pool(mempool), m_view(&m_dummy), m_viewmempool(&active_chainstate.CoinsTip(), m_pool), m_active_chainstate(active_chainstate), m_limit_ancestors(m_pool.m_limits.ancestor_count), m_limit_ancestor_size(m_pool.m_limits.ancestor_size_vbytes), m_limit_descendants(m_pool.m_limits.descendant_count), m_limit_descendant_size(m_pool.m_limits.descendant_size_vbytes) { } // We put the arguments we're handed into a struct, so we can pass them // around easier. struct ATMPArgs { const CChainParams& m_chainparams; const int64_t m_accept_time; const bool m_bypass_limits; /* * Return any outpoints which were not previously present in the coins * cache, but were added as a result of validating the tx for mempool * acceptance. This allows the caller to optionally remove the cache * additions if the associated transaction ends up being rejected by * the mempool. */ std::vector<COutPoint>& m_coins_to_uncache; const bool m_test_accept; /** Whether we allow transactions to replace mempool transactions by BIP125 rules. If false, * any transaction spending the same inputs as a transaction in the mempool is considered * a conflict. */ const bool m_allow_replacement; /** When true, the mempool will not be trimmed when individual transactions are submitted in * Finalize(). Instead, limits should be enforced at the end to ensure the package is not * partially submitted. */ const bool m_package_submission; /** When true, use package feerates instead of individual transaction feerates for fee-based * policies such as mempool min fee and min relay fee. */ const bool m_package_feerates; /** Parameters for single transaction mempool validation. */ static ATMPArgs SingleAccept(const CChainParams& chainparams, int64_t accept_time, bool bypass_limits, std::vector<COutPoint>& coins_to_uncache, bool test_accept) { return ATMPArgs{/* m_chainparams */ chainparams, /* m_accept_time */ accept_time, /* m_bypass_limits */ bypass_limits, /* m_coins_to_uncache */ coins_to_uncache, /* m_test_accept */ test_accept, /* m_allow_replacement */ true, /* m_package_submission */ false, /* m_package_feerates */ false, }; } /** Parameters for test package mempool validation through testmempoolaccept. */ static ATMPArgs PackageTestAccept(const CChainParams& chainparams, int64_t accept_time, std::vector<COutPoint>& coins_to_uncache) { return ATMPArgs{/* m_chainparams */ chainparams, /* m_accept_time */ accept_time, /* m_bypass_limits */ false, /* m_coins_to_uncache */ coins_to_uncache, /* m_test_accept */ true, /* m_allow_replacement */ false, /* m_package_submission */ false, // not submitting to mempool /* m_package_feerates */ false, }; } /** Parameters for child-with-unconfirmed-parents package validation. */ static ATMPArgs PackageChildWithParents(const CChainParams& chainparams, int64_t accept_time, std::vector<COutPoint>& coins_to_uncache) { return ATMPArgs{/* m_chainparams */ chainparams, /* m_accept_time */ accept_time, /* m_bypass_limits */ false, /* m_coins_to_uncache */ coins_to_uncache, /* m_test_accept */ false, /* m_allow_replacement */ false, /* m_package_submission */ true, /* m_package_feerates */ true, }; } /** Parameters for a single transaction within a package. */ static ATMPArgs SingleInPackageAccept(const ATMPArgs& package_args) { return ATMPArgs{/* m_chainparams */ package_args.m_chainparams, /* m_accept_time */ package_args.m_accept_time, /* m_bypass_limits */ false, /* m_coins_to_uncache */ package_args.m_coins_to_uncache, /* m_test_accept */ package_args.m_test_accept, /* m_allow_replacement */ true, /* m_package_submission */ false, /* m_package_feerates */ false, // only 1 transaction }; } private: // Private ctor to avoid exposing details to clients and allowing the possibility of // mixing up the order of the arguments. Use static functions above instead. ATMPArgs(const CChainParams& chainparams, int64_t accept_time, bool bypass_limits, std::vector<COutPoint>& coins_to_uncache, bool test_accept, bool allow_replacement, bool package_submission, bool package_feerates) : m_chainparams{chainparams}, m_accept_time{accept_time}, m_bypass_limits{bypass_limits}, m_coins_to_uncache{coins_to_uncache}, m_test_accept{test_accept}, m_allow_replacement{allow_replacement}, m_package_submission{package_submission}, m_package_feerates{package_feerates} { } }; // Single transaction acceptance MempoolAcceptResult AcceptSingleTransaction(const CTransactionRef& ptx, ATMPArgs& args) EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** * Multiple transaction acceptance. Transactions may or may not be interdependent, but must not * conflict with each other, and the transactions cannot already be in the mempool. Parents must * come before children if any dependencies exist. */ PackageMempoolAcceptResult AcceptMultipleTransactions(const std::vector<CTransactionRef>& txns, ATMPArgs& args) EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** * Package (more specific than just multiple transactions) acceptance. Package must be a child * with all of its unconfirmed parents, and topologically sorted. */ PackageMempoolAcceptResult AcceptPackage(const Package& package, ATMPArgs& args) EXCLUSIVE_LOCKS_REQUIRED(cs_main); private: // All the intermediate state that gets passed between the various levels // of checking a given transaction. struct Workspace { explicit Workspace(const CTransactionRef& ptx) : m_ptx(ptx), m_hash(ptx->GetHash()) {} /** Txids of mempool transactions that this transaction directly conflicts with. */ std::set<uint256> m_conflicts; /** Iterators to mempool entries that this transaction directly conflicts with. */ CTxMemPool::setEntries m_iters_conflicting; /** Iterators to all mempool entries that would be replaced by this transaction, including * those it directly conflicts with and their descendants. */ CTxMemPool::setEntries m_all_conflicting; /** All mempool ancestors of this transaction. */ CTxMemPool::setEntries m_ancestors; /** Mempool entry constructed for this transaction. Constructed in PreChecks() but not * inserted into the mempool until Finalize(). */ std::unique_ptr<CTxMemPoolEntry> m_entry; /** Pointers to the transactions that have been removed from the mempool and replaced by * this transaction, used to return to the MemPoolAccept caller. Only populated if * validation is successful and the original transactions are removed. */ std::list<CTransactionRef> m_replaced_transactions; /** Virtual size of the transaction as used by the mempool, calculated using serialized size * of the transaction and sigops. */ int64_t m_vsize; /** Fees paid by this transaction: total input amounts subtracted by total output amounts. */ CAmount m_base_fees; /** Base fees + any fee delta set by the user with prioritisetransaction. */ CAmount m_modified_fees; /** Total modified fees of all transactions being replaced. */ CAmount m_conflicting_fees{0}; /** Total virtual size of all transactions being replaced. */ size_t m_conflicting_size{0}; const CTransactionRef& m_ptx; /** Txid. */ const uint256& m_hash; TxValidationState m_state; /** A temporary cache containing serialized transaction data for signature verification. * Reused across PolicyScriptChecks and ConsensusScriptChecks. */ PrecomputedTransactionData m_precomputed_txdata; }; // Run the policy checks on a given transaction, excluding any script checks. // Looks up inputs, calculates feerate, considers replacement, evaluates // package limits, etc. As this function can be invoked for "free" by a peer, // only tests that are fast should be done here (to avoid CPU DoS). bool PreChecks(ATMPArgs& args, Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); // Run checks for mempool replace-by-fee. bool ReplacementChecks(Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); // Enforce package mempool ancestor/descendant limits (distinct from individual // ancestor/descendant limits done in PreChecks). bool PackageMempoolChecks(const std::vector<CTransactionRef>& txns, PackageValidationState& package_state) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); // Run the script checks using our policy flags. As this can be slow, we should // only invoke this on transactions that have otherwise passed policy checks. bool PolicyScriptChecks(const ATMPArgs& args, Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); // Re-run the script checks, using consensus flags, and try to cache the // result in the scriptcache. This should be done after // PolicyScriptChecks(). This requires that all inputs either be in our // utxo set or in the mempool. bool ConsensusScriptChecks(const ATMPArgs& args, Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); // Try to add the transaction to the mempool, removing any conflicts first. // Returns true if the transaction is in the mempool after any size // limiting is performed, false otherwise. bool Finalize(const ATMPArgs& args, Workspace& ws) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); // Submit all transactions to the mempool and call ConsensusScriptChecks to add to the script // cache - should only be called after successful validation of all transactions in the package. // The package may end up partially-submitted after size limiting; returns true if all // transactions are successfully added to the mempool, false otherwise. bool SubmitPackage(const ATMPArgs& args, std::vector<Workspace>& workspaces, PackageValidationState& package_state, std::map<const uint256, const MempoolAcceptResult>& results) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs); // Compare a package's feerate against minimum allowed. bool CheckFeeRate(size_t package_size, CAmount package_fee, TxValidationState& state) EXCLUSIVE_LOCKS_REQUIRED(::cs_main, m_pool.cs) { AssertLockHeld(::cs_main); AssertLockHeld(m_pool.cs); CAmount mempoolRejectFee = m_pool.GetMinFee().GetFee(package_size); if (mempoolRejectFee > 0 && package_fee < mempoolRejectFee) { return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "mempool min fee not met", strprintf("%d < %d", package_fee, mempoolRejectFee)); } if (package_fee < m_pool.m_min_relay_feerate.GetFee(package_size)) { return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "min relay fee not met", strprintf("%d < %d", package_fee, m_pool.m_min_relay_feerate.GetFee(package_size))); } return true; } private: CTxMemPool& m_pool; CCoinsViewCache m_view; CCoinsViewMemPool m_viewmempool; CCoinsView m_dummy; Chainstate& m_active_chainstate; // The package limits in effect at the time of invocation. const size_t m_limit_ancestors; const size_t m_limit_ancestor_size; // These may be modified while evaluating a transaction (eg to account for // in-mempool conflicts; see below). size_t m_limit_descendants; size_t m_limit_descendant_size; /** Whether the transaction(s) would replace any mempool transactions. If so, RBF rules apply. */ bool m_rbf{false}; }; bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws) { AssertLockHeld(cs_main); AssertLockHeld(m_pool.cs); const CTransactionRef& ptx = ws.m_ptx; const CTransaction& tx = *ws.m_ptx; const uint256& hash = ws.m_hash; // Copy/alias what we need out of args const int64_t nAcceptTime = args.m_accept_time; const bool bypass_limits = args.m_bypass_limits; std::vector<COutPoint>& coins_to_uncache = args.m_coins_to_uncache; // Alias what we need out of ws TxValidationState& state = ws.m_state; std::unique_ptr<CTxMemPoolEntry>& entry = ws.m_entry; if (!CheckTransaction(tx, state)) { return false; // state filled in by CheckTransaction } // Coinbase is only valid in a block, not as a loose transaction if (tx.IsCoinBase()) return state.Invalid(TxValidationResult::TX_CONSENSUS, "coinbase"); // Rather not work on nonstandard transactions (unless -testnet/-regtest) std::string reason; if (m_pool.m_require_standard && !IsStandardTx(tx, m_pool.m_max_datacarrier_bytes, m_pool.m_permit_bare_multisig, m_pool.m_dust_relay_feerate, reason)) { return state.Invalid(TxValidationResult::TX_NOT_STANDARD, reason); } // Do not work on transactions that are too small. // A transaction with 1 segwit input and 1 P2WPHK output has non-witness size of 82 bytes. // Transactions smaller than this are not relayed to mitigate CVE-2017-12842 by not relaying // 64-byte transactions. if (::GetSerializeSize(tx, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) < MIN_STANDARD_TX_NONWITNESS_SIZE) return state.Invalid(TxValidationResult::TX_NOT_STANDARD, "tx-size-small"); // Only accept nLockTime-using transactions that can be mined in the next // block; we don't want our mempool filled up with transactions that can't // be mined yet. if (!CheckFinalTxAtTip(*Assert(m_active_chainstate.m_chain.Tip()), tx)) { return state.Invalid(TxValidationResult::TX_PREMATURE_SPEND, "non-final"); } if (m_pool.exists(GenTxid::Wtxid(tx.GetWitnessHash()))) { // Exact transaction already exists in the mempool. return state.Invalid(TxValidationResult::TX_CONFLICT, "txn-already-in-mempool"); } else if (m_pool.exists(GenTxid::Txid(tx.GetHash()))) { // Transaction with the same non-witness data but different witness (same txid, different // wtxid) already exists in the mempool. return state.Invalid(TxValidationResult::TX_CONFLICT, "txn-same-nonwitness-data-in-mempool"); } // Check for conflicts with in-memory transactions for (const CTxIn &txin : tx.vin) { const CTransaction* ptxConflicting = m_pool.GetConflictTx(txin.prevout); if (ptxConflicting) { if (!args.m_allow_replacement) { // Transaction conflicts with a mempool tx, but we're not allowing replacements. return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "bip125-replacement-disallowed"); } if (!ws.m_conflicts.count(ptxConflicting->GetHash())) { // Transactions that don't explicitly signal replaceability are // *not* replaceable with the current logic, even if one of their // unconfirmed ancestors signals replaceability. This diverges // from BIP125's inherited signaling description (see CVE-2021-31876). // Applications relying on first-seen mempool behavior should // check all unconfirmed ancestors; otherwise an opt-in ancestor // might be replaced, causing removal of this descendant. // // If replaceability signaling is ignored due to node setting, // replacement is always allowed. if (!m_pool.m_full_rbf && !SignalsOptInRBF(*ptxConflicting)) { return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "txn-mempool-conflict"); } ws.m_conflicts.insert(ptxConflicting->GetHash()); } } } LockPoints lp; m_view.SetBackend(m_viewmempool); const CCoinsViewCache& coins_cache = m_active_chainstate.CoinsTip(); // do all inputs exist? for (const CTxIn& txin : tx.vin) { if (!coins_cache.HaveCoinInCache(txin.prevout)) { coins_to_uncache.push_back(txin.prevout); } // Note: this call may add txin.prevout to the coins cache // (coins_cache.cacheCoins) by way of FetchCoin(). It should be removed // later (via coins_to_uncache) if this tx turns out to be invalid. if (!m_view.HaveCoin(txin.prevout)) { // Are inputs missing because we already have the tx? for (size_t out = 0; out < tx.vout.size(); out++) { // Optimistically just do efficient check of cache for outputs if (coins_cache.HaveCoinInCache(COutPoint(hash, out))) { return state.Invalid(TxValidationResult::TX_CONFLICT, "txn-already-known"); } } // Otherwise assume this might be an orphan tx for which we just haven't seen parents yet return state.Invalid(TxValidationResult::TX_MISSING_INPUTS, "bad-txns-inputs-missingorspent"); } } // This is const, but calls into the back end CoinsViews. The CCoinsViewDB at the bottom of the // hierarchy brings the best block into scope. See CCoinsViewDB::GetBestBlock(). m_view.GetBestBlock(); // we have all inputs cached now, so switch back to dummy (to protect // against bugs where we pull more inputs from disk that miss being added // to coins_to_uncache) m_view.SetBackend(m_dummy); assert(m_active_chainstate.m_blockman.LookupBlockIndex(m_view.GetBestBlock()) == m_active_chainstate.m_chain.Tip()); // Only accept BIP68 sequence locked transactions that can be mined in the next // block; we don't want our mempool filled up with transactions that can't // be mined yet. // Pass in m_view which has all of the relevant inputs cached. Note that, since m_view's // backend was removed, it no longer pulls coins from the mempool. if (!CheckSequenceLocksAtTip(m_active_chainstate.m_chain.Tip(), m_view, tx, &lp)) { return state.Invalid(TxValidationResult::TX_PREMATURE_SPEND, "non-BIP68-final"); } // The mempool holds txs for the next block, so pass height+1 to CheckTxInputs if (!Consensus::CheckTxInputs(tx, state, m_view, m_active_chainstate.m_chain.Height() + 1, ws.m_base_fees)) { return false; // state filled in by CheckTxInputs } if (m_pool.m_require_standard && !AreInputsStandard(tx, m_view)) { return state.Invalid(TxValidationResult::TX_INPUTS_NOT_STANDARD, "bad-txns-nonstandard-inputs"); } // Check for non-standard witnesses. if (tx.HasWitness() && m_pool.m_require_standard && !IsWitnessStandard(tx, m_view)) { return state.Invalid(TxValidationResult::TX_WITNESS_MUTATED, "bad-witness-nonstandard"); } int64_t nSigOpsCost = GetTransactionSigOpCost(tx, m_view, STANDARD_SCRIPT_VERIFY_FLAGS); // ws.m_modified_fees includes any fee deltas from PrioritiseTransaction ws.m_modified_fees = ws.m_base_fees; m_pool.ApplyDelta(hash, ws.m_modified_fees); // Keep track of transactions that spend a coinbase, which we re-scan // during reorgs to ensure COINBASE_MATURITY is still met. bool fSpendsCoinbase = false; for (const CTxIn &txin : tx.vin) { const Coin &coin = m_view.AccessCoin(txin.prevout); if (coin.IsCoinBase()) { fSpendsCoinbase = true; break; } } entry.reset(new CTxMemPoolEntry(ptx, ws.m_base_fees, nAcceptTime, m_active_chainstate.m_chain.Height(), fSpendsCoinbase, nSigOpsCost, lp)); ws.m_vsize = entry->GetTxSize(); if (nSigOpsCost > MAX_STANDARD_TX_SIGOPS_COST) return state.Invalid(TxValidationResult::TX_NOT_STANDARD, "bad-txns-too-many-sigops", strprintf("%d", nSigOpsCost)); // No individual transactions are allowed below the min relay feerate and mempool min feerate except from // disconnected blocks and transactions in a package. Package transactions will be checked using // package feerate later. if (!bypass_limits && !args.m_package_feerates && !CheckFeeRate(ws.m_vsize, ws.m_modified_fees, state)) return false; ws.m_iters_conflicting = m_pool.GetIterSet(ws.m_conflicts); // Calculate in-mempool ancestors, up to a limit. if (ws.m_conflicts.size() == 1) { // In general, when we receive an RBF transaction with mempool conflicts, we want to know whether we // would meet the chain limits after the conflicts have been removed. However, there isn't a practical // way to do this short of calculating the ancestor and descendant sets with an overlay cache of // changed mempool entries. Due to both implementation and runtime complexity concerns, this isn't // very realistic, thus we only ensure a limited set of transactions are RBF'able despite mempool // conflicts here. Importantly, we need to ensure that some transactions which were accepted using // the below carve-out are able to be RBF'ed, without impacting the security the carve-out provides // for off-chain contract systems (see link in the comment below). // // Specifically, the subset of RBF transactions which we allow despite chain limits are those which // conflict directly with exactly one other transaction (but may evict children of said transaction), // and which are not adding any new mempool dependencies. Note that the "no new mempool dependencies" // check is accomplished later, so we don't bother doing anything about it here, but if our // policy changes, we may need to move that check to here instead of removing it wholesale. // // Such transactions are clearly not merging any existing packages, so we are only concerned with // ensuring that (a) no package is growing past the package size (not count) limits and (b) we are // not allowing something to effectively use the (below) carve-out spot when it shouldn't be allowed // to. // // To check these we first check if we meet the RBF criteria, above, and increment the descendant // limits by the direct conflict and its descendants (as these are recalculated in // CalculateMempoolAncestors by assuming the new transaction being added is a new descendant, with no // removals, of each parent's existing dependent set). The ancestor count limits are unmodified (as // the ancestor limits should be the same for both our new transaction and any conflicts). // We don't bother incrementing m_limit_descendants by the full removal count as that limit never comes // into force here (as we're only adding a single transaction). assert(ws.m_iters_conflicting.size() == 1); CTxMemPool::txiter conflict = *ws.m_iters_conflicting.begin(); m_limit_descendants += 1; m_limit_descendant_size += conflict->GetSizeWithDescendants(); } std::string errString; if (!m_pool.CalculateMemPoolAncestors(*entry, ws.m_ancestors, m_limit_ancestors, m_limit_ancestor_size, m_limit_descendants, m_limit_descendant_size, errString)) { ws.m_ancestors.clear(); // If CalculateMemPoolAncestors fails second time, we want the original error string. std::string dummy_err_string; // Contracting/payment channels CPFP carve-out: // If the new transaction is relatively small (up to 40k weight) // and has at most one ancestor (ie ancestor limit of 2, including // the new transaction), allow it if its parent has exactly the // descendant limit descendants. // // This allows protocols which rely on distrusting counterparties // being able to broadcast descendants of an unconfirmed transaction // to be secure by simply only having two immediately-spendable // outputs - one for each counterparty. For more info on the uses for // this, see https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-November/016518.html if (ws.m_vsize > EXTRA_DESCENDANT_TX_SIZE_LIMIT || !m_pool.CalculateMemPoolAncestors(*entry, ws.m_ancestors, 2, m_limit_ancestor_size, m_limit_descendants + 1, m_limit_descendant_size + EXTRA_DESCENDANT_TX_SIZE_LIMIT, dummy_err_string)) { return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "too-long-mempool-chain", errString); } } // A transaction that spends outputs that would be replaced by it is invalid. Now // that we have the set of all ancestors we can detect this // pathological case by making sure ws.m_conflicts and ws.m_ancestors don't // intersect. if (const auto err_string{EntriesAndTxidsDisjoint(ws.m_ancestors, ws.m_conflicts, hash)}) { // We classify this as a consensus error because a transaction depending on something it // conflicts with would be inconsistent. return state.Invalid(TxValidationResult::TX_CONSENSUS, "bad-txns-spends-conflicting-tx", *err_string); } m_rbf = !ws.m_conflicts.empty(); return true; } bool MemPoolAccept::ReplacementChecks(Workspace& ws) { AssertLockHeld(cs_main); AssertLockHeld(m_pool.cs); const CTransaction& tx = *ws.m_ptx; const uint256& hash = ws.m_hash; TxValidationState& state = ws.m_state; CFeeRate newFeeRate(ws.m_modified_fees, ws.m_vsize); // Enforce Rule #6. The replacement transaction must have a higher feerate than its direct conflicts. // - The motivation for this check is to ensure that the replacement transaction is preferable for // block-inclusion, compared to what would be removed from the mempool. // - This logic predates ancestor feerate-based transaction selection, which is why it doesn't // consider feerates of descendants. // - Note: Ancestor feerate-based transaction selection has made this comparison insufficient to // guarantee that this is incentive-compatible for miners, because it is possible for a // descendant transaction of a direct conflict to pay a higher feerate than the transaction that // might replace them, under these rules. if (const auto err_string{PaysMoreThanConflicts(ws.m_iters_conflicting, newFeeRate, hash)}) { return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "insufficient fee", *err_string); } // Calculate all conflicting entries and enforce Rule #5. if (const auto err_string{GetEntriesForConflicts(tx, m_pool, ws.m_iters_conflicting, ws.m_all_conflicting)}) { return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "too many potential replacements", *err_string); } // Enforce Rule #2. if (const auto err_string{HasNoNewUnconfirmed(tx, m_pool, ws.m_iters_conflicting)}) { return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "replacement-adds-unconfirmed", *err_string); } // Check if it's economically rational to mine this transaction rather than the ones it // replaces and pays for its own relay fees. Enforce Rules #3 and #4. for (CTxMemPool::txiter it : ws.m_all_conflicting) { ws.m_conflicting_fees += it->GetModifiedFee(); ws.m_conflicting_size += it->GetTxSize(); } if (const auto err_string{PaysForRBF(ws.m_conflicting_fees, ws.m_modified_fees, ws.m_vsize, m_pool.m_incremental_relay_feerate, hash)}) { return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "insufficient fee", *err_string); } return true; } bool MemPoolAccept::PackageMempoolChecks(const std::vector<CTransactionRef>& txns, PackageValidationState& package_state) { AssertLockHeld(cs_main); AssertLockHeld(m_pool.cs); // CheckPackageLimits expects the package transactions to not already be in the mempool. assert(std::all_of(txns.cbegin(), txns.cend(), [this](const auto& tx) { return !m_pool.exists(GenTxid::Txid(tx->GetHash()));})); std::string err_string; if (!m_pool.CheckPackageLimits(txns, m_limit_ancestors, m_limit_ancestor_size, m_limit_descendants, m_limit_descendant_size, err_string)) { // This is a package-wide error, separate from an individual transaction error. return package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package-mempool-limits", err_string); } return true; } bool MemPoolAccept::PolicyScriptChecks(const ATMPArgs& args, Workspace& ws) { AssertLockHeld(cs_main); AssertLockHeld(m_pool.cs); const CTransaction& tx = *ws.m_ptx; TxValidationState& state = ws.m_state; constexpr unsigned int scriptVerifyFlags = STANDARD_SCRIPT_VERIFY_FLAGS; // Check input scripts and signatures. // This is done last to help prevent CPU exhaustion denial-of-service attacks. if (!CheckInputScripts(tx, state, m_view, scriptVerifyFlags, true, false, ws.m_precomputed_txdata)) { // SCRIPT_VERIFY_CLEANSTACK requires SCRIPT_VERIFY_WITNESS, so we // need to turn both off, and compare against just turning off CLEANSTACK // to see if the failure is specifically due to witness validation. TxValidationState state_dummy; // Want reported failures to be from first CheckInputScripts if (!tx.HasWitness() && CheckInputScripts(tx, state_dummy, m_view, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true, false, ws.m_precomputed_txdata) && !CheckInputScripts(tx, state_dummy, m_view, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true, false, ws.m_precomputed_txdata)) { // Only the witness is missing, so the transaction itself may be fine. state.Invalid(TxValidationResult::TX_WITNESS_STRIPPED, state.GetRejectReason(), state.GetDebugMessage()); } return false; // state filled in by CheckInputScripts } return true; } bool MemPoolAccept::ConsensusScriptChecks(const ATMPArgs& args, Workspace& ws) { AssertLockHeld(cs_main); AssertLockHeld(m_pool.cs); const CTransaction& tx = *ws.m_ptx; const uint256& hash = ws.m_hash; TxValidationState& state = ws.m_state; // Check again against the current block tip's script verification // flags to cache our script execution flags. This is, of course, // useless if the next block has different script flags from the // previous one, but because the cache tracks script flags for us it // will auto-invalidate and we'll just have a few blocks of extra // misses on soft-fork activation. // // This is also useful in case of bugs in the standard flags that cause // transactions to pass as valid when they're actually invalid. For // instance the STRICTENC flag was incorrectly allowing certain // CHECKSIG NOT scripts to pass, even though they were invalid. // // There is a similar check in CreateNewBlock() to prevent creating // invalid blocks (using TestBlockValidity), however allowing such // transactions into the mempool can be exploited as a DoS attack. unsigned int currentBlockScriptVerifyFlags{GetBlockScriptFlags(*m_active_chainstate.m_chain.Tip(), m_active_chainstate.m_chainman)}; if (!CheckInputsFromMempoolAndCache(tx, state, m_view, m_pool, currentBlockScriptVerifyFlags, ws.m_precomputed_txdata, m_active_chainstate.CoinsTip())) { LogPrintf("BUG! PLEASE REPORT THIS! CheckInputScripts failed against latest-block but not STANDARD flags %s, %s\n", hash.ToString(), state.ToString()); return Assume(false); } return true; } bool MemPoolAccept::Finalize(const ATMPArgs& args, Workspace& ws) { AssertLockHeld(cs_main); AssertLockHeld(m_pool.cs); const CTransaction& tx = *ws.m_ptx; const uint256& hash = ws.m_hash; TxValidationState& state = ws.m_state; const bool bypass_limits = args.m_bypass_limits; std::unique_ptr<CTxMemPoolEntry>& entry = ws.m_entry; // Remove conflicting transactions from the mempool for (CTxMemPool::txiter it : ws.m_all_conflicting) { LogPrint(BCLog::MEMPOOL, "replacing tx %s with %s for %s additional fees, %d delta bytes\n", it->GetTx().GetHash().ToString(), hash.ToString(), FormatMoney(ws.m_modified_fees - ws.m_conflicting_fees), (int)entry->GetTxSize() - (int)ws.m_conflicting_size); ws.m_replaced_transactions.push_back(it->GetSharedTx()); } m_pool.RemoveStaged(ws.m_all_conflicting, false, MemPoolRemovalReason::REPLACED); // This transaction should only count for fee estimation if: // - it's not being re-added during a reorg which bypasses typical mempool fee limits // - the node is not behind // - the transaction is not dependent on any other transactions in the mempool // - it's not part of a package. Since package relay is not currently supported, this // transaction has not necessarily been accepted to miners' mempools. bool validForFeeEstimation = !bypass_limits && !args.m_package_submission && IsCurrentForFeeEstimation(m_active_chainstate) && m_pool.HasNoInputsOf(tx); // Store transaction in memory m_pool.addUnchecked(*entry, ws.m_ancestors, validForFeeEstimation); // trim mempool and check if tx was trimmed // If we are validating a package, don't trim here because we could evict a previous transaction // in the package. LimitMempoolSize() should be called at the very end to make sure the mempool // is still within limits and package submission happens atomically. if (!args.m_package_submission && !bypass_limits) { LimitMempoolSize(m_pool, m_active_chainstate.CoinsTip()); if (!m_pool.exists(GenTxid::Txid(hash))) return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "mempool full"); } return true; } bool MemPoolAccept::SubmitPackage(const ATMPArgs& args, std::vector<Workspace>& workspaces, PackageValidationState& package_state, std::map<const uint256, const MempoolAcceptResult>& results) { AssertLockHeld(cs_main); AssertLockHeld(m_pool.cs); // Sanity check: none of the transactions should be in the mempool, and none of the transactions // should have a same-txid-different-witness equivalent in the mempool. assert(std::all_of(workspaces.cbegin(), workspaces.cend(), [this](const auto& ws){ return !m_pool.exists(GenTxid::Txid(ws.m_ptx->GetHash())); })); bool all_submitted = true; // ConsensusScriptChecks adds to the script cache and is therefore consensus-critical; // CheckInputsFromMempoolAndCache asserts that transactions only spend coins available from the // mempool or UTXO set. Submit each transaction to the mempool immediately after calling // ConsensusScriptChecks to make the outputs available for subsequent transactions. for (Workspace& ws : workspaces) { if (!ConsensusScriptChecks(args, ws)) { results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state)); // Since PolicyScriptChecks() passed, this should never fail. Assume(false); all_submitted = false; package_state.Invalid(PackageValidationResult::PCKG_MEMPOOL_ERROR, strprintf("BUG! PolicyScriptChecks succeeded but ConsensusScriptChecks failed: %s", ws.m_ptx->GetHash().ToString())); } // Re-calculate mempool ancestors to call addUnchecked(). They may have changed since the // last calculation done in PreChecks, since package ancestors have already been submitted. std::string unused_err_string; if(!m_pool.CalculateMemPoolAncestors(*ws.m_entry, ws.m_ancestors, m_limit_ancestors, m_limit_ancestor_size, m_limit_descendants, m_limit_descendant_size, unused_err_string)) { results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state)); // Since PreChecks() and PackageMempoolChecks() both enforce limits, this should never fail. Assume(false); all_submitted = false; package_state.Invalid(PackageValidationResult::PCKG_MEMPOOL_ERROR, strprintf("BUG! Mempool ancestors or descendants were underestimated: %s", ws.m_ptx->GetHash().ToString())); } // If we call LimitMempoolSize() for each individual Finalize(), the mempool will not take // the transaction's descendant feerate into account because it hasn't seen them yet. Also, // we risk evicting a transaction that a subsequent package transaction depends on. Instead, // allow the mempool to temporarily bypass limits, the maximum package size) while // submitting transactions individually and then trim at the very end. if (!Finalize(args, ws)) { results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state)); // Since LimitMempoolSize() won't be called, this should never fail. Assume(false); all_submitted = false; package_state.Invalid(PackageValidationResult::PCKG_MEMPOOL_ERROR, strprintf("BUG! Adding to mempool failed: %s", ws.m_ptx->GetHash().ToString())); } } // It may or may not be the case that all the transactions made it into the mempool. Regardless, // make sure we haven't exceeded max mempool size. LimitMempoolSize(m_pool, m_active_chainstate.CoinsTip()); // Find the wtxids of the transactions that made it into the mempool. Allow partial submission, // but don't report success unless they all made it into the mempool. for (Workspace& ws : workspaces) { if (m_pool.exists(GenTxid::Wtxid(ws.m_ptx->GetWitnessHash()))) { results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Success(std::move(ws.m_replaced_transactions), ws.m_vsize, ws.m_base_fees)); GetMainSignals().TransactionAddedToMempool(ws.m_ptx, m_pool.GetAndIncrementSequence()); } else { all_submitted = false; ws.m_state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "mempool full"); results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state)); } } return all_submitted; } MempoolAcceptResult MemPoolAccept::AcceptSingleTransaction(const CTransactionRef& ptx, ATMPArgs& args) { AssertLockHeld(cs_main); LOCK(m_pool.cs); // mempool "read lock" (held through GetMainSignals().TransactionAddedToMempool()) Workspace ws(ptx); if (!PreChecks(args, ws)) return MempoolAcceptResult::Failure(ws.m_state); if (m_rbf && !ReplacementChecks(ws)) return MempoolAcceptResult::Failure(ws.m_state); // Perform the inexpensive checks first and avoid hashing and signature verification unless // those checks pass, to mitigate CPU exhaustion denial-of-service attacks. if (!PolicyScriptChecks(args, ws)) return MempoolAcceptResult::Failure(ws.m_state); if (!ConsensusScriptChecks(args, ws)) return MempoolAcceptResult::Failure(ws.m_state); // Tx was accepted, but not added if (args.m_test_accept) { return MempoolAcceptResult::Success(std::move(ws.m_replaced_transactions), ws.m_vsize, ws.m_base_fees); } if (!Finalize(args, ws)) return MempoolAcceptResult::Failure(ws.m_state); GetMainSignals().TransactionAddedToMempool(ptx, m_pool.GetAndIncrementSequence()); return MempoolAcceptResult::Success(std::move(ws.m_replaced_transactions), ws.m_vsize, ws.m_base_fees); } PackageMempoolAcceptResult MemPoolAccept::AcceptMultipleTransactions(const std::vector<CTransactionRef>& txns, ATMPArgs& args) { AssertLockHeld(cs_main); // These context-free package limits can be done before taking the mempool lock. PackageValidationState package_state; if (!CheckPackage(txns, package_state)) return PackageMempoolAcceptResult(package_state, {}); std::vector<Workspace> workspaces{}; workspaces.reserve(txns.size()); std::transform(txns.cbegin(), txns.cend(), std::back_inserter(workspaces), [](const auto& tx) { return Workspace(tx); }); std::map<const uint256, const MempoolAcceptResult> results; LOCK(m_pool.cs); // Do all PreChecks first and fail fast to avoid running expensive script checks when unnecessary. for (Workspace& ws : workspaces) { if (!PreChecks(args, ws)) { package_state.Invalid(PackageValidationResult::PCKG_TX, "transaction failed"); // Exit early to avoid doing pointless work. Update the failed tx result; the rest are unfinished. results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state)); return PackageMempoolAcceptResult(package_state, std::move(results)); } // Make the coins created by this transaction available for subsequent transactions in the // package to spend. Since we already checked conflicts in the package and we don't allow // replacements, we don't need to track the coins spent. Note that this logic will need to be // updated if package replace-by-fee is allowed in the future. assert(!args.m_allow_replacement); m_viewmempool.PackageAddTransaction(ws.m_ptx); } // Transactions must meet two minimum feerates: the mempool minimum fee and min relay fee. // For transactions consisting of exactly one child and its parents, it suffices to use the // package feerate (total modified fees / total virtual size) to check this requirement. const auto m_total_vsize = std::accumulate(workspaces.cbegin(), workspaces.cend(), int64_t{0}, [](int64_t sum, auto& ws) { return sum + ws.m_vsize; }); const auto m_total_modified_fees = std::accumulate(workspaces.cbegin(), workspaces.cend(), CAmount{0}, [](CAmount sum, auto& ws) { return sum + ws.m_modified_fees; }); const CFeeRate package_feerate(m_total_modified_fees, m_total_vsize); TxValidationState placeholder_state; if (args.m_package_feerates && !CheckFeeRate(m_total_vsize, m_total_modified_fees, placeholder_state)) { package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package-fee-too-low"); return PackageMempoolAcceptResult(package_state, package_feerate, {}); } // Apply package mempool ancestor/descendant limits. Skip if there is only one transaction, // because it's unnecessary. Also, CPFP carve out can increase the limit for individual // transactions, but this exemption is not extended to packages in CheckPackageLimits(). std::string err_string; if (txns.size() > 1 && !PackageMempoolChecks(txns, package_state)) { return PackageMempoolAcceptResult(package_state, package_feerate, std::move(results)); } for (Workspace& ws : workspaces) { if (!PolicyScriptChecks(args, ws)) { // Exit early to avoid doing pointless work. Update the failed tx result; the rest are unfinished. package_state.Invalid(PackageValidationResult::PCKG_TX, "transaction failed"); results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Failure(ws.m_state)); return PackageMempoolAcceptResult(package_state, package_feerate, std::move(results)); } if (args.m_test_accept) { // When test_accept=true, transactions that pass PolicyScriptChecks are valid because there are // no further mempool checks (passing PolicyScriptChecks implies passing ConsensusScriptChecks). results.emplace(ws.m_ptx->GetWitnessHash(), MempoolAcceptResult::Success(std::move(ws.m_replaced_transactions), ws.m_vsize, ws.m_base_fees)); } } if (args.m_test_accept) return PackageMempoolAcceptResult(package_state, package_feerate, std::move(results)); if (!SubmitPackage(args, workspaces, package_state, results)) { // PackageValidationState filled in by SubmitPackage(). return PackageMempoolAcceptResult(package_state, package_feerate, std::move(results)); } return PackageMempoolAcceptResult(package_state, package_feerate, std::move(results)); } PackageMempoolAcceptResult MemPoolAccept::AcceptPackage(const Package& package, ATMPArgs& args) { AssertLockHeld(cs_main); PackageValidationState package_state; // Check that the package is well-formed. If it isn't, we won't try to validate any of the // transactions and thus won't return any MempoolAcceptResults, just a package-wide error. // Context-free package checks. if (!CheckPackage(package, package_state)) return PackageMempoolAcceptResult(package_state, {}); // All transactions in the package must be a parent of the last transaction. This is just an // opportunity for us to fail fast on a context-free check without taking the mempool lock. if (!IsChildWithParents(package)) { package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package-not-child-with-parents"); return PackageMempoolAcceptResult(package_state, {}); } // IsChildWithParents() guarantees the package is > 1 transactions. assert(package.size() > 1); // The package must be 1 child with all of its unconfirmed parents. The package is expected to // be sorted, so the last transaction is the child. const auto& child = package.back(); std::unordered_set<uint256, SaltedTxidHasher> unconfirmed_parent_txids; std::transform(package.cbegin(), package.cend() - 1, std::inserter(unconfirmed_parent_txids, unconfirmed_parent_txids.end()), [](const auto& tx) { return tx->GetHash(); }); // All child inputs must refer to a preceding package transaction or a confirmed UTXO. The only // way to verify this is to look up the child's inputs in our current coins view (not including // mempool), and enforce that all parents not present in the package be available at chain tip. // Since this check can bring new coins into the coins cache, keep track of these coins and // uncache them if we don't end up submitting this package to the mempool. const CCoinsViewCache& coins_tip_cache = m_active_chainstate.CoinsTip(); for (const auto& input : child->vin) { if (!coins_tip_cache.HaveCoinInCache(input.prevout)) { args.m_coins_to_uncache.push_back(input.prevout); } } // Using the MemPoolAccept m_view cache allows us to look up these same coins faster later. // This should be connecting directly to CoinsTip, not to m_viewmempool, because we specifically // require inputs to be confirmed if they aren't in the package. m_view.SetBackend(m_active_chainstate.CoinsTip()); const auto package_or_confirmed = [this, &unconfirmed_parent_txids](const auto& input) { return unconfirmed_parent_txids.count(input.prevout.hash) > 0 || m_view.HaveCoin(input.prevout); }; if (!std::all_of(child->vin.cbegin(), child->vin.cend(), package_or_confirmed)) { package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package-not-child-with-unconfirmed-parents"); return PackageMempoolAcceptResult(package_state, {}); } // Protect against bugs where we pull more inputs from disk that miss being added to // coins_to_uncache. The backend will be connected again when needed in PreChecks. m_view.SetBackend(m_dummy); LOCK(m_pool.cs); std::map<const uint256, const MempoolAcceptResult> results; // Node operators are free to set their mempool policies however they please, nodes may receive // transactions in different orders, and malicious counterparties may try to take advantage of // policy differences to pin or delay propagation of transactions. As such, it's possible for // some package transaction(s) to already be in the mempool, and we don't want to reject the // entire package in that case (as that could be a censorship vector). De-duplicate the // transactions that are already in the mempool, and only call AcceptMultipleTransactions() with // the new transactions. This ensures we don't double-count transaction counts and sizes when // checking ancestor/descendant limits, or double-count transaction fees for fee-related policy. ATMPArgs single_args = ATMPArgs::SingleInPackageAccept(args); bool quit_early{false}; std::vector<CTransactionRef> txns_new; for (const auto& tx : package) { const auto& wtxid = tx->GetWitnessHash(); const auto& txid = tx->GetHash(); // There are 3 possibilities: already in mempool, same-txid-diff-wtxid already in mempool, // or not in mempool. An already confirmed tx is treated as one not in mempool, because all // we know is that the inputs aren't available. if (m_pool.exists(GenTxid::Wtxid(wtxid))) { // Exact transaction already exists in the mempool. auto iter = m_pool.GetIter(txid); assert(iter != std::nullopt); results.emplace(wtxid, MempoolAcceptResult::MempoolTx(iter.value()->GetTxSize(), iter.value()->GetFee())); } else if (m_pool.exists(GenTxid::Txid(txid))) { // Transaction with the same non-witness data but different witness (same txid, // different wtxid) already exists in the mempool. // // We don't allow replacement transactions right now, so just swap the package // transaction for the mempool one. Note that we are ignoring the validity of the // package transaction passed in. // TODO: allow witness replacement in packages. auto iter = m_pool.GetIter(txid); assert(iter != std::nullopt); // Provide the wtxid of the mempool tx so that the caller can look it up in the mempool. results.emplace(wtxid, MempoolAcceptResult::MempoolTxDifferentWitness(iter.value()->GetTx().GetWitnessHash())); } else { // Transaction does not already exist in the mempool. // Try submitting the transaction on its own. const auto single_res = AcceptSingleTransaction(tx, single_args); if (single_res.m_result_type == MempoolAcceptResult::ResultType::VALID) { // The transaction succeeded on its own and is now in the mempool. Don't include it // in package validation, because its fees should only be "used" once. assert(m_pool.exists(GenTxid::Wtxid(wtxid))); results.emplace(wtxid, single_res); } else if (single_res.m_state.GetResult() != TxValidationResult::TX_MEMPOOL_POLICY && single_res.m_state.GetResult() != TxValidationResult::TX_MISSING_INPUTS) { // Package validation policy only differs from individual policy in its evaluation // of feerate. For example, if a transaction fails here due to violation of a // consensus rule, the result will not change when it is submitted as part of a // package. To minimize the amount of repeated work, unless the transaction fails // due to feerate or missing inputs (its parent is a previous transaction in the // package that failed due to feerate), don't run package validation. Note that this // decision might not make sense if different types of packages are allowed in the // future. Continue individually validating the rest of the transactions, because // some of them may still be valid. quit_early = true; } else { txns_new.push_back(tx); } } } // Nothing to do if the entire package has already been submitted. if (quit_early || txns_new.empty()) { // No package feerate when no package validation was done. return PackageMempoolAcceptResult(package_state, std::move(results)); } // Validate the (deduplicated) transactions as a package. auto submission_result = AcceptMultipleTransactions(txns_new, args); // Include already-in-mempool transaction results in the final result. for (const auto& [wtxid, mempoolaccept_res] : results) { submission_result.m_tx_results.emplace(wtxid, mempoolaccept_res); } if (submission_result.m_state.IsValid()) assert(submission_result.m_package_feerate.has_value()); return submission_result; } } // anon namespace MempoolAcceptResult AcceptToMemoryPool(Chainstate& active_chainstate, const CTransactionRef& tx, int64_t accept_time, bool bypass_limits, bool test_accept) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); const CChainParams& chainparams{active_chainstate.m_params}; assert(active_chainstate.GetMempool() != nullptr); CTxMemPool& pool{*active_chainstate.GetMempool()}; std::vector<COutPoint> coins_to_uncache; auto args = MemPoolAccept::ATMPArgs::SingleAccept(chainparams, accept_time, bypass_limits, coins_to_uncache, test_accept); const MempoolAcceptResult result = MemPoolAccept(pool, active_chainstate).AcceptSingleTransaction(tx, args); if (result.m_result_type != MempoolAcceptResult::ResultType::VALID) { // Remove coins that were not present in the coins cache before calling // AcceptSingleTransaction(); this is to prevent memory DoS in case we receive a large // number of invalid transactions that attempt to overrun the in-memory coins cache // (`CCoinsViewCache::cacheCoins`). for (const COutPoint& hashTx : coins_to_uncache) active_chainstate.CoinsTip().Uncache(hashTx); } // After we've (potentially) uncached entries, ensure our coins cache is still within its size limits BlockValidationState state_dummy; active_chainstate.FlushStateToDisk(state_dummy, FlushStateMode::PERIODIC); return result; } PackageMempoolAcceptResult ProcessNewPackage(Chainstate& active_chainstate, CTxMemPool& pool, const Package& package, bool test_accept) { AssertLockHeld(cs_main); assert(!package.empty()); assert(std::all_of(package.cbegin(), package.cend(), [](const auto& tx){return tx != nullptr;})); std::vector<COutPoint> coins_to_uncache; const CChainParams& chainparams = active_chainstate.m_params; const auto result = [&]() EXCLUSIVE_LOCKS_REQUIRED(cs_main) { AssertLockHeld(cs_main); if (test_accept) { auto args = MemPoolAccept::ATMPArgs::PackageTestAccept(chainparams, GetTime(), coins_to_uncache); return MemPoolAccept(pool, active_chainstate).AcceptMultipleTransactions(package, args); } else { auto args = MemPoolAccept::ATMPArgs::PackageChildWithParents(chainparams, GetTime(), coins_to_uncache); return MemPoolAccept(pool, active_chainstate).AcceptPackage(package, args); } }(); // Uncache coins pertaining to transactions that were not submitted to the mempool. if (test_accept || result.m_state.IsInvalid()) { for (const COutPoint& hashTx : coins_to_uncache) { active_chainstate.CoinsTip().Uncache(hashTx); } } // Ensure the coins cache is still within limits. BlockValidationState state_dummy; active_chainstate.FlushStateToDisk(state_dummy, FlushStateMode::PERIODIC); return result; } CAmount GetBlockSubsidy(int nHeight, const Consensus::Params& consensusParams) { int halvings = nHeight / consensusParams.nSubsidyHalvingInterval; // Force block reward to zero when right shift is undefined. if (halvings >= 64) return 0; CAmount nSubsidy = 50 * COIN; // Subsidy is cut in half every 210,000 blocks which will occur approximately every 4 years. nSubsidy >>= halvings; return nSubsidy; } CoinsViews::CoinsViews( fs::path ldb_name, size_t cache_size_bytes, bool in_memory, bool should_wipe) : m_dbview( gArgs.GetDataDirNet() / ldb_name, cache_size_bytes, in_memory, should_wipe), m_catcherview(&m_dbview) {} void CoinsViews::InitCache() { AssertLockHeld(::cs_main); m_cacheview = std::make_unique<CCoinsViewCache>(&m_catcherview); } Chainstate::Chainstate( CTxMemPool* mempool, BlockManager& blockman, ChainstateManager& chainman, std::optional<uint256> from_snapshot_blockhash) : m_mempool(mempool), m_blockman(blockman), m_params(chainman.GetParams()), m_chainman(chainman), m_from_snapshot_blockhash(from_snapshot_blockhash) {} void Chainstate::InitCoinsDB( size_t cache_size_bytes, bool in_memory, bool should_wipe, fs::path leveldb_name) { if (m_from_snapshot_blockhash) { leveldb_name += "_" + m_from_snapshot_blockhash->ToString(); } m_coins_views = std::make_unique<CoinsViews>( leveldb_name, cache_size_bytes, in_memory, should_wipe); } void Chainstate::InitCoinsCache(size_t cache_size_bytes) { AssertLockHeld(::cs_main); assert(m_coins_views != nullptr); m_coinstip_cache_size_bytes = cache_size_bytes; m_coins_views->InitCache(); } // Note that though this is marked const, we may end up modifying `m_cached_finished_ibd`, which // is a performance-related implementation detail. This function must be marked // `const` so that `CValidationInterface` clients (which are given a `const Chainstate*`) // can call it. // bool Chainstate::IsInitialBlockDownload() const { // Optimization: pre-test latch before taking the lock. if (m_cached_finished_ibd.load(std::memory_order_relaxed)) return false; LOCK(cs_main); if (m_cached_finished_ibd.load(std::memory_order_relaxed)) return false; if (fImporting || fReindex) return true; if (m_chain.Tip() == nullptr) return true; if (m_chain.Tip()->nChainWork < nMinimumChainWork) return true; if (m_chain.Tip()->GetBlockTime() < (GetTime() - nMaxTipAge)) return true; LogPrintf("Leaving InitialBlockDownload (latching to false)\n"); m_cached_finished_ibd.store(true, std::memory_order_relaxed); return false; } static void AlertNotify(const std::string& strMessage) { uiInterface.NotifyAlertChanged(); #if HAVE_SYSTEM std::string strCmd = gArgs.GetArg("-alertnotify", ""); if (strCmd.empty()) return; // Alert text should be plain ascii coming from a trusted source, but to // be safe we first strip anything not in safeChars, then add single quotes around // the whole string before passing it to the shell: std::string singleQuote("'"); std::string safeStatus = SanitizeString(strMessage); safeStatus = singleQuote+safeStatus+singleQuote; ReplaceAll(strCmd, "%s", safeStatus); std::thread t(runCommand, strCmd); t.detach(); // thread runs free #endif } void Chainstate::CheckForkWarningConditions() { AssertLockHeld(cs_main); // Before we get past initial download, we cannot reliably alert about forks // (we assume we don't get stuck on a fork before finishing our initial sync) if (IsInitialBlockDownload()) { return; } if (m_chainman.m_best_invalid && m_chainman.m_best_invalid->nChainWork > m_chain.Tip()->nChainWork + (GetBlockProof(*m_chain.Tip()) * 6)) { LogPrintf("%s: Warning: Found invalid chain at least ~6 blocks longer than our best chain.\nChain state database corruption likely.\n", __func__); SetfLargeWorkInvalidChainFound(true); } else { SetfLargeWorkInvalidChainFound(false); } } // Called both upon regular invalid block discovery *and* InvalidateBlock void Chainstate::InvalidChainFound(CBlockIndex* pindexNew) { AssertLockHeld(cs_main); if (!m_chainman.m_best_invalid || pindexNew->nChainWork > m_chainman.m_best_invalid->nChainWork) { m_chainman.m_best_invalid = pindexNew; } if (m_chainman.m_best_header != nullptr && m_chainman.m_best_header->GetAncestor(pindexNew->nHeight) == pindexNew) { m_chainman.m_best_header = m_chain.Tip(); } LogPrintf("%s: invalid block=%s height=%d log2_work=%f date=%s\n", __func__, pindexNew->GetBlockHash().ToString(), pindexNew->nHeight, log(pindexNew->nChainWork.getdouble())/log(2.0), FormatISO8601DateTime(pindexNew->GetBlockTime())); CBlockIndex *tip = m_chain.Tip(); assert (tip); LogPrintf("%s: current best=%s height=%d log2_work=%f date=%s\n", __func__, tip->GetBlockHash().ToString(), m_chain.Height(), log(tip->nChainWork.getdouble())/log(2.0), FormatISO8601DateTime(tip->GetBlockTime())); CheckForkWarningConditions(); } // Same as InvalidChainFound, above, except not called directly from InvalidateBlock, // which does its own setBlockIndexCandidates management. void Chainstate::InvalidBlockFound(CBlockIndex* pindex, const BlockValidationState& state) { AssertLockHeld(cs_main); if (state.GetResult() != BlockValidationResult::BLOCK_MUTATED) { pindex->nStatus |= BLOCK_FAILED_VALID; m_chainman.m_failed_blocks.insert(pindex); m_blockman.m_dirty_blockindex.insert(pindex); setBlockIndexCandidates.erase(pindex); InvalidChainFound(pindex); } } void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, CTxUndo &txundo, int nHeight) { // mark inputs spent if (!tx.IsCoinBase()) { txundo.vprevout.reserve(tx.vin.size()); for (const CTxIn &txin : tx.vin) { txundo.vprevout.emplace_back(); bool is_spent = inputs.SpendCoin(txin.prevout, &txundo.vprevout.back()); assert(is_spent); } } // add outputs AddCoins(inputs, tx, nHeight); } bool CScriptCheck::operator()() { const CScript &scriptSig = ptxTo->vin[nIn].scriptSig; const CScriptWitness *witness = &ptxTo->vin[nIn].scriptWitness; return VerifyScript(scriptSig, m_tx_out.scriptPubKey, witness, nFlags, CachingTransactionSignatureChecker(ptxTo, nIn, m_tx_out.nValue, cacheStore, *txdata), &error); } static CuckooCache::cache<uint256, SignatureCacheHasher> g_scriptExecutionCache; static CSHA256 g_scriptExecutionCacheHasher; bool InitScriptExecutionCache(size_t max_size_bytes) { // Setup the salted hasher uint256 nonce = GetRandHash(); // We want the nonce to be 64 bytes long to force the hasher to process // this chunk, which makes later hash computations more efficient. We // just write our 32-byte entropy twice to fill the 64 bytes. g_scriptExecutionCacheHasher.Write(nonce.begin(), 32); g_scriptExecutionCacheHasher.Write(nonce.begin(), 32); auto setup_results = g_scriptExecutionCache.setup_bytes(max_size_bytes); if (!setup_results) return false; const auto [num_elems, approx_size_bytes] = *setup_results; LogPrintf("Using %zu MiB out of %zu MiB requested for script execution cache, able to store %zu elements\n", approx_size_bytes >> 20, max_size_bytes >> 20, num_elems); return true; } /** * Check whether all of this transaction's input scripts succeed. * * This involves ECDSA signature checks so can be computationally intensive. This function should * only be called after the cheap sanity checks in CheckTxInputs passed. * * If pvChecks is not nullptr, script checks are pushed onto it instead of being performed inline. Any * script checks which are not necessary (eg due to script execution cache hits) are, obviously, * not pushed onto pvChecks/run. * * Setting cacheSigStore/cacheFullScriptStore to false will remove elements from the corresponding cache * which are matched. This is useful for checking blocks where we will likely never need the cache * entry again. * * Note that we may set state.reason to NOT_STANDARD for extra soft-fork flags in flags, block-checking * callers should probably reset it to CONSENSUS in such cases. * * Non-static (and re-declared) in src/test/txvalidationcache_tests.cpp */ bool CheckInputScripts(const CTransaction& tx, TxValidationState& state, const CCoinsViewCache& inputs, unsigned int flags, bool cacheSigStore, bool cacheFullScriptStore, PrecomputedTransactionData& txdata, std::vector<CScriptCheck>* pvChecks) { if (tx.IsCoinBase()) return true; if (pvChecks) { pvChecks->reserve(tx.vin.size()); } // First check if script executions have been cached with the same // flags. Note that this assumes that the inputs provided are // correct (ie that the transaction hash which is in tx's prevouts // properly commits to the scriptPubKey in the inputs view of that // transaction). uint256 hashCacheEntry; CSHA256 hasher = g_scriptExecutionCacheHasher; hasher.Write(tx.GetWitnessHash().begin(), 32).Write((unsigned char*)&flags, sizeof(flags)).Finalize(hashCacheEntry.begin()); AssertLockHeld(cs_main); //TODO: Remove this requirement by making CuckooCache not require external locks if (g_scriptExecutionCache.contains(hashCacheEntry, !cacheFullScriptStore)) { return true; } if (!txdata.m_spent_outputs_ready) { std::vector<CTxOut> spent_outputs; spent_outputs.reserve(tx.vin.size()); for (const auto& txin : tx.vin) { const COutPoint& prevout = txin.prevout; const Coin& coin = inputs.AccessCoin(prevout); assert(!coin.IsSpent()); spent_outputs.emplace_back(coin.out); } txdata.Init(tx, std::move(spent_outputs)); } assert(txdata.m_spent_outputs.size() == tx.vin.size()); for (unsigned int i = 0; i < tx.vin.size(); i++) { // We very carefully only pass in things to CScriptCheck which // are clearly committed to by tx' witness hash. This provides // a sanity check that our caching is not introducing consensus // failures through additional data in, eg, the coins being // spent being checked as a part of CScriptCheck. // Verify signature CScriptCheck check(txdata.m_spent_outputs[i], tx, i, flags, cacheSigStore, &txdata); if (pvChecks) { pvChecks->push_back(CScriptCheck()); check.swap(pvChecks->back()); } else if (!check()) { if (flags & STANDARD_NOT_MANDATORY_VERIFY_FLAGS) { // Check whether the failure was caused by a // non-mandatory script verification check, such as // non-standard DER encodings or non-null dummy // arguments; if so, ensure we return NOT_STANDARD // instead of CONSENSUS to avoid downstream users // splitting the network between upgraded and // non-upgraded nodes by banning CONSENSUS-failing // data providers. CScriptCheck check2(txdata.m_spent_outputs[i], tx, i, flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheSigStore, &txdata); if (check2()) return state.Invalid(TxValidationResult::TX_NOT_STANDARD, strprintf("non-mandatory-script-verify-flag (%s)", ScriptErrorString(check.GetScriptError()))); } // MANDATORY flag failures correspond to // TxValidationResult::TX_CONSENSUS. Because CONSENSUS // failures are the most serious case of validation // failures, we may need to consider using // RECENT_CONSENSUS_CHANGE for any script failure that // could be due to non-upgraded nodes which we may want to // support, to avoid splitting the network (but this // depends on the details of how net_processing handles // such errors). return state.Invalid(TxValidationResult::TX_CONSENSUS, strprintf("mandatory-script-verify-flag-failed (%s)", ScriptErrorString(check.GetScriptError()))); } } if (cacheFullScriptStore && !pvChecks) { // We executed all of the provided scripts, and were told to // cache the result. Do so now. g_scriptExecutionCache.insert(hashCacheEntry); } return true; } bool AbortNode(BlockValidationState& state, const std::string& strMessage, const bilingual_str& userMessage) { AbortNode(strMessage, userMessage); return state.Error(strMessage); } /** * Restore the UTXO in a Coin at a given COutPoint * @param undo The Coin to be restored. * @param view The coins view to which to apply the changes. * @param out The out point that corresponds to the tx input. * @return A DisconnectResult as an int */ int ApplyTxInUndo(Coin&& undo, CCoinsViewCache& view, const COutPoint& out) { bool fClean = true; if (view.HaveCoin(out)) fClean = false; // overwriting transaction output if (undo.nHeight == 0) { // Missing undo metadata (height and coinbase). Older versions included this // information only in undo records for the last spend of a transactions' // outputs. This implies that it must be present for some other output of the same tx. const Coin& alternate = AccessByTxid(view, out.hash); if (!alternate.IsSpent()) { undo.nHeight = alternate.nHeight; undo.fCoinBase = alternate.fCoinBase; } else { return DISCONNECT_FAILED; // adding output for transaction without known metadata } } // If the coin already exists as an unspent coin in the cache, then the // possible_overwrite parameter to AddCoin must be set to true. We have // already checked whether an unspent coin exists above using HaveCoin, so // we don't need to guess. When fClean is false, an unspent coin already // existed and it is an overwrite. view.AddCoin(out, std::move(undo), !fClean); return fClean ? DISCONNECT_OK : DISCONNECT_UNCLEAN; } /** Undo the effects of this block (with given index) on the UTXO set represented by coins. * When FAILED is returned, view is left in an indeterminate state. */ DisconnectResult Chainstate::DisconnectBlock(const CBlock& block, const CBlockIndex* pindex, CCoinsViewCache& view) { AssertLockHeld(::cs_main); bool fClean = true; CBlockUndo blockUndo; if (!UndoReadFromDisk(blockUndo, pindex)) { error("DisconnectBlock(): failure reading undo data"); return DISCONNECT_FAILED; } if (blockUndo.vtxundo.size() + 1 != block.vtx.size()) { error("DisconnectBlock(): block and undo data inconsistent"); return DISCONNECT_FAILED; } // undo transactions in reverse order for (int i = block.vtx.size() - 1; i >= 0; i--) { const CTransaction &tx = *(block.vtx[i]); uint256 hash = tx.GetHash(); bool is_coinbase = tx.IsCoinBase(); // Check that all outputs are available and match the outputs in the block itself // exactly. for (size_t o = 0; o < tx.vout.size(); o++) { if (!tx.vout[o].scriptPubKey.IsUnspendable()) { COutPoint out(hash, o); Coin coin; bool is_spent = view.SpendCoin(out, &coin); if (!is_spent || tx.vout[o] != coin.out || pindex->nHeight != coin.nHeight || is_coinbase != coin.fCoinBase) { fClean = false; // transaction output mismatch } } } // restore inputs if (i > 0) { // not coinbases CTxUndo &txundo = blockUndo.vtxundo[i-1]; if (txundo.vprevout.size() != tx.vin.size()) { error("DisconnectBlock(): transaction and undo data inconsistent"); return DISCONNECT_FAILED; } for (unsigned int j = tx.vin.size(); j > 0;) { --j; const COutPoint& out = tx.vin[j].prevout; int res = ApplyTxInUndo(std::move(txundo.vprevout[j]), view, out); if (res == DISCONNECT_FAILED) return DISCONNECT_FAILED; fClean = fClean && res != DISCONNECT_UNCLEAN; } // At this point, all of txundo.vprevout should have been moved out. } } // move best block pointer to prevout block view.SetBestBlock(pindex->pprev->GetBlockHash()); return fClean ? DISCONNECT_OK : DISCONNECT_UNCLEAN; } static CCheckQueue<CScriptCheck> scriptcheckqueue(128); void StartScriptCheckWorkerThreads(int threads_num) { scriptcheckqueue.StartWorkerThreads(threads_num); } void StopScriptCheckWorkerThreads() { scriptcheckqueue.StopWorkerThreads(); } /** * Threshold condition checker that triggers when unknown versionbits are seen on the network. */ class WarningBitsConditionChecker : public AbstractThresholdConditionChecker { private: const ChainstateManager& m_chainman; int m_bit; public: explicit WarningBitsConditionChecker(const ChainstateManager& chainman, int bit) : m_chainman{chainman}, m_bit(bit) {} int64_t BeginTime(const Consensus::Params& params) const override { return 0; } int64_t EndTime(const Consensus::Params& params) const override { return std::numeric_limits<int64_t>::max(); } int Period(const Consensus::Params& params) const override { return params.nMinerConfirmationWindow; } int Threshold(const Consensus::Params& params) const override { return params.nRuleChangeActivationThreshold; } bool Condition(const CBlockIndex* pindex, const Consensus::Params& params) const override { return pindex->nHeight >= params.MinBIP9WarningHeight && ((pindex->nVersion & VERSIONBITS_TOP_MASK) == VERSIONBITS_TOP_BITS) && ((pindex->nVersion >> m_bit) & 1) != 0 && ((m_chainman.m_versionbitscache.ComputeBlockVersion(pindex->pprev, params) >> m_bit) & 1) == 0; } }; static std::array<ThresholdConditionCache, VERSIONBITS_NUM_BITS> warningcache GUARDED_BY(cs_main); static unsigned int GetBlockScriptFlags(const CBlockIndex& block_index, const ChainstateManager& chainman) { const Consensus::Params& consensusparams = chainman.GetConsensus(); // BIP16 didn't become active until Apr 1 2012 (on mainnet, and // retroactively applied to testnet) // However, only one historical block violated the P2SH rules (on both // mainnet and testnet). // Similarly, only one historical block violated the TAPROOT rules on // mainnet. // For simplicity, always leave P2SH+WITNESS+TAPROOT on except for the two // violating blocks. uint32_t flags{SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_TAPROOT}; const auto it{consensusparams.script_flag_exceptions.find(*Assert(block_index.phashBlock))}; if (it != consensusparams.script_flag_exceptions.end()) { flags = it->second; } // Enforce the DERSIG (BIP66) rule if (DeploymentActiveAt(block_index, chainman, Consensus::DEPLOYMENT_DERSIG)) { flags |= SCRIPT_VERIFY_DERSIG; } // Enforce CHECKLOCKTIMEVERIFY (BIP65) if (DeploymentActiveAt(block_index, chainman, Consensus::DEPLOYMENT_CLTV)) { flags |= SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY; } // Enforce CHECKSEQUENCEVERIFY (BIP112) if (DeploymentActiveAt(block_index, chainman, Consensus::DEPLOYMENT_CSV)) { flags |= SCRIPT_VERIFY_CHECKSEQUENCEVERIFY; } // Enforce BIP147 NULLDUMMY (activated simultaneously with segwit) if (DeploymentActiveAt(block_index, chainman, Consensus::DEPLOYMENT_SEGWIT)) { flags |= SCRIPT_VERIFY_NULLDUMMY; } return flags; } static int64_t nTimeCheck = 0; static int64_t nTimeForks = 0; static int64_t nTimeConnect = 0; static int64_t nTimeVerify = 0; static int64_t nTimeUndo = 0; static int64_t nTimeIndex = 0; static int64_t nTimeTotal = 0; static int64_t nBlocksTotal = 0; /** Apply the effects of this block (with given index) on the UTXO set represented by coins. * Validity checks that depend on the UTXO set are also done; ConnectBlock() * can fail if those validity checks fail (among other reasons). */ bool Chainstate::ConnectBlock(const CBlock& block, BlockValidationState& state, CBlockIndex* pindex, CCoinsViewCache& view, bool fJustCheck) { AssertLockHeld(cs_main); assert(pindex); uint256 block_hash{block.GetHash()}; assert(*pindex->phashBlock == block_hash); int64_t nTimeStart = GetTimeMicros(); // Check it again in case a previous version let a bad block in // NOTE: We don't currently (re-)invoke ContextualCheckBlock() or // ContextualCheckBlockHeader() here. This means that if we add a new // consensus rule that is enforced in one of those two functions, then we // may have let in a block that violates the rule prior to updating the // software, and we would NOT be enforcing the rule here. Fully solving // upgrade from one software version to the next after a consensus rule // change is potentially tricky and issue-specific (see NeedsRedownload() // for one approach that was used for BIP 141 deployment). // Also, currently the rule against blocks more than 2 hours in the future // is enforced in ContextualCheckBlockHeader(); we wouldn't want to // re-enforce that rule here (at least until we make it impossible for // m_adjusted_time_callback() to go backward). if (!CheckBlock(block, state, m_params.GetConsensus(), !fJustCheck, !fJustCheck)) { if (state.GetResult() == BlockValidationResult::BLOCK_MUTATED) { // We don't write down blocks to disk if they may have been // corrupted, so this should be impossible unless we're having hardware // problems. return AbortNode(state, "Corrupt block found indicating potential hardware failure; shutting down"); } return error("%s: Consensus::CheckBlock: %s", __func__, state.ToString()); } // verify that the view's current state corresponds to the previous block uint256 hashPrevBlock = pindex->pprev == nullptr ? uint256() : pindex->pprev->GetBlockHash(); assert(hashPrevBlock == view.GetBestBlock()); nBlocksTotal++; // Special case for the genesis block, skipping connection of its transactions // (its coinbase is unspendable) if (block_hash == m_params.GetConsensus().hashGenesisBlock) { if (!fJustCheck) view.SetBestBlock(pindex->GetBlockHash()); return true; } bool fScriptChecks = true; if (!hashAssumeValid.IsNull()) { // We've been configured with the hash of a block which has been externally verified to have a valid history. // A suitable default value is included with the software and updated from time to time. Because validity // relative to a piece of software is an objective fact these defaults can be easily reviewed. // This setting doesn't force the selection of any particular chain but makes validating some faster by // effectively caching the result of part of the verification. BlockMap::const_iterator it = m_blockman.m_block_index.find(hashAssumeValid); if (it != m_blockman.m_block_index.end()) { if (it->second.GetAncestor(pindex->nHeight) == pindex && m_chainman.m_best_header->GetAncestor(pindex->nHeight) == pindex && m_chainman.m_best_header->nChainWork >= nMinimumChainWork) { // This block is a member of the assumed verified chain and an ancestor of the best header. // Script verification is skipped when connecting blocks under the // assumevalid block. Assuming the assumevalid block is valid this // is safe because block merkle hashes are still computed and checked, // Of course, if an assumed valid block is invalid due to false scriptSigs // this optimization would allow an invalid chain to be accepted. // The equivalent time check discourages hash power from extorting the network via DOS attack // into accepting an invalid block through telling users they must manually set assumevalid. // Requiring a software change or burying the invalid block, regardless of the setting, makes // it hard to hide the implication of the demand. This also avoids having release candidates // that are hardly doing any signature verification at all in testing without having to // artificially set the default assumed verified block further back. // The test against nMinimumChainWork prevents the skipping when denied access to any chain at // least as good as the expected chain. fScriptChecks = (GetBlockProofEquivalentTime(*m_chainman.m_best_header, *pindex, *m_chainman.m_best_header, m_params.GetConsensus()) <= 60 * 60 * 24 * 7 * 2); } } } int64_t nTime1 = GetTimeMicros(); nTimeCheck += nTime1 - nTimeStart; LogPrint(BCLog::BENCH, " - Sanity checks: %.2fms [%.2fs (%.2fms/blk)]\n", MILLI * (nTime1 - nTimeStart), nTimeCheck * MICRO, nTimeCheck * MILLI / nBlocksTotal); // Do not allow blocks that contain transactions which 'overwrite' older transactions, // unless those are already completely spent. // If such overwrites are allowed, coinbases and transactions depending upon those // can be duplicated to remove the ability to spend the first instance -- even after // being sent to another address. // See BIP30, CVE-2012-1909, and http://r6.ca/blog/20120206T005236Z.html for more information. // This rule was originally applied to all blocks with a timestamp after March 15, 2012, 0:00 UTC. // Now that the whole chain is irreversibly beyond that time it is applied to all blocks except the // two in the chain that violate it. This prevents exploiting the issue against nodes during their // initial block download. bool fEnforceBIP30 = !((pindex->nHeight==91842 && pindex->GetBlockHash() == uint256S("0x00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec")) || (pindex->nHeight==91880 && pindex->GetBlockHash() == uint256S("0x00000000000743f190a18c5577a3c2d2a1f610ae9601ac046a38084ccb7cd721"))); // Once BIP34 activated it was not possible to create new duplicate coinbases and thus other than starting // with the 2 existing duplicate coinbase pairs, not possible to create overwriting txs. But by the // time BIP34 activated, in each of the existing pairs the duplicate coinbase had overwritten the first // before the first had been spent. Since those coinbases are sufficiently buried it's no longer possible to create further // duplicate transactions descending from the known pairs either. // If we're on the known chain at height greater than where BIP34 activated, we can save the db accesses needed for the BIP30 check. // BIP34 requires that a block at height X (block X) has its coinbase // scriptSig start with a CScriptNum of X (indicated height X). The above // logic of no longer requiring BIP30 once BIP34 activates is flawed in the // case that there is a block X before the BIP34 height of 227,931 which has // an indicated height Y where Y is greater than X. The coinbase for block // X would also be a valid coinbase for block Y, which could be a BIP30 // violation. An exhaustive search of all mainnet coinbases before the // BIP34 height which have an indicated height greater than the block height // reveals many occurrences. The 3 lowest indicated heights found are // 209,921, 490,897, and 1,983,702 and thus coinbases for blocks at these 3 // heights would be the first opportunity for BIP30 to be violated. // The search reveals a great many blocks which have an indicated height // greater than 1,983,702, so we simply remove the optimization to skip // BIP30 checking for blocks at height 1,983,702 or higher. Before we reach // that block in another 25 years or so, we should take advantage of a // future consensus change to do a new and improved version of BIP34 that // will actually prevent ever creating any duplicate coinbases in the // future. static constexpr int BIP34_IMPLIES_BIP30_LIMIT = 1983702; // There is no potential to create a duplicate coinbase at block 209,921 // because this is still before the BIP34 height and so explicit BIP30 // checking is still active. // The final case is block 176,684 which has an indicated height of // 490,897. Unfortunately, this issue was not discovered until about 2 weeks // before block 490,897 so there was not much opportunity to address this // case other than to carefully analyze it and determine it would not be a // problem. Block 490,897 was, in fact, mined with a different coinbase than // block 176,684, but it is important to note that even if it hadn't been or // is remined on an alternate fork with a duplicate coinbase, we would still // not run into a BIP30 violation. This is because the coinbase for 176,684 // is spent in block 185,956 in transaction // d4f7fbbf92f4a3014a230b2dc70b8058d02eb36ac06b4a0736d9d60eaa9e8781. This // spending transaction can't be duplicated because it also spends coinbase // 0328dd85c331237f18e781d692c92de57649529bd5edf1d01036daea32ffde29. This // coinbase has an indicated height of over 4.2 billion, and wouldn't be // duplicatable until that height, and it's currently impossible to create a // chain that long. Nevertheless we may wish to consider a future soft fork // which retroactively prevents block 490,897 from creating a duplicate // coinbase. The two historical BIP30 violations often provide a confusing // edge case when manipulating the UTXO and it would be simpler not to have // another edge case to deal with. // testnet3 has no blocks before the BIP34 height with indicated heights // post BIP34 before approximately height 486,000,000. After block // 1,983,702 testnet3 starts doing unnecessary BIP30 checking again. assert(pindex->pprev); CBlockIndex* pindexBIP34height = pindex->pprev->GetAncestor(m_params.GetConsensus().BIP34Height); //Only continue to enforce if we're below BIP34 activation height or the block hash at that height doesn't correspond. fEnforceBIP30 = fEnforceBIP30 && (!pindexBIP34height || !(pindexBIP34height->GetBlockHash() == m_params.GetConsensus().BIP34Hash)); // TODO: Remove BIP30 checking from block height 1,983,702 on, once we have a // consensus change that ensures coinbases at those heights cannot // duplicate earlier coinbases. if (fEnforceBIP30 || pindex->nHeight >= BIP34_IMPLIES_BIP30_LIMIT) { for (const auto& tx : block.vtx) { for (size_t o = 0; o < tx->vout.size(); o++) { if (view.HaveCoin(COutPoint(tx->GetHash(), o))) { LogPrintf("ERROR: ConnectBlock(): tried to overwrite transaction\n"); return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-txns-BIP30"); } } } } // Enforce BIP68 (sequence locks) int nLockTimeFlags = 0; if (DeploymentActiveAt(*pindex, m_chainman, Consensus::DEPLOYMENT_CSV)) { nLockTimeFlags |= LOCKTIME_VERIFY_SEQUENCE; } // Get the script flags for this block unsigned int flags{GetBlockScriptFlags(*pindex, m_chainman)}; int64_t nTime2 = GetTimeMicros(); nTimeForks += nTime2 - nTime1; LogPrint(BCLog::BENCH, " - Fork checks: %.2fms [%.2fs (%.2fms/blk)]\n", MILLI * (nTime2 - nTime1), nTimeForks * MICRO, nTimeForks * MILLI / nBlocksTotal); CBlockUndo blockundo; // Precomputed transaction data pointers must not be invalidated // until after `control` has run the script checks (potentially // in multiple threads). Preallocate the vector size so a new allocation // doesn't invalidate pointers into the vector, and keep txsdata in scope // for as long as `control`. CCheckQueueControl<CScriptCheck> control(fScriptChecks && g_parallel_script_checks ? &scriptcheckqueue : nullptr); std::vector<PrecomputedTransactionData> txsdata(block.vtx.size()); std::vector<int> prevheights; CAmount nFees = 0; int nInputs = 0; int64_t nSigOpsCost = 0; blockundo.vtxundo.reserve(block.vtx.size() - 1); for (unsigned int i = 0; i < block.vtx.size(); i++) { const CTransaction &tx = *(block.vtx[i]); nInputs += tx.vin.size(); if (!tx.IsCoinBase()) { CAmount txfee = 0; TxValidationState tx_state; if (!Consensus::CheckTxInputs(tx, tx_state, view, pindex->nHeight, txfee)) { // Any transaction validation failure in ConnectBlock is a block consensus failure state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, tx_state.GetRejectReason(), tx_state.GetDebugMessage()); return error("%s: Consensus::CheckTxInputs: %s, %s", __func__, tx.GetHash().ToString(), state.ToString()); } nFees += txfee; if (!MoneyRange(nFees)) { LogPrintf("ERROR: %s: accumulated fee in the block out of range.\n", __func__); return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-txns-accumulated-fee-outofrange"); } // Check that transaction is BIP68 final // BIP68 lock checks (as opposed to nLockTime checks) must // be in ConnectBlock because they require the UTXO set prevheights.resize(tx.vin.size()); for (size_t j = 0; j < tx.vin.size(); j++) { prevheights[j] = view.AccessCoin(tx.vin[j].prevout).nHeight; } if (!SequenceLocks(tx, nLockTimeFlags, prevheights, *pindex)) { LogPrintf("ERROR: %s: contains a non-BIP68-final transaction\n", __func__); return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-txns-nonfinal"); } } // GetTransactionSigOpCost counts 3 types of sigops: // * legacy (always) // * p2sh (when P2SH enabled in flags and excludes coinbase) // * witness (when witness enabled in flags and excludes coinbase) nSigOpsCost += GetTransactionSigOpCost(tx, view, flags); if (nSigOpsCost > MAX_BLOCK_SIGOPS_COST) { LogPrintf("ERROR: ConnectBlock(): too many sigops\n"); return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-blk-sigops"); } if (!tx.IsCoinBase()) { std::vector<CScriptCheck> vChecks; bool fCacheResults = fJustCheck; /* Don't cache results if we're actually connecting blocks (still consult the cache, though) */ TxValidationState tx_state; if (fScriptChecks && !CheckInputScripts(tx, tx_state, view, flags, fCacheResults, fCacheResults, txsdata[i], g_parallel_script_checks ? &vChecks : nullptr)) { // Any transaction validation failure in ConnectBlock is a block consensus failure state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, tx_state.GetRejectReason(), tx_state.GetDebugMessage()); return error("ConnectBlock(): CheckInputScripts on %s failed with %s", tx.GetHash().ToString(), state.ToString()); } control.Add(vChecks); } CTxUndo undoDummy; if (i > 0) { blockundo.vtxundo.push_back(CTxUndo()); } UpdateCoins(tx, view, i == 0 ? undoDummy : blockundo.vtxundo.back(), pindex->nHeight); } int64_t nTime3 = GetTimeMicros(); nTimeConnect += nTime3 - nTime2; LogPrint(BCLog::BENCH, " - Connect %u transactions: %.2fms (%.3fms/tx, %.3fms/txin) [%.2fs (%.2fms/blk)]\n", (unsigned)block.vtx.size(), MILLI * (nTime3 - nTime2), MILLI * (nTime3 - nTime2) / block.vtx.size(), nInputs <= 1 ? 0 : MILLI * (nTime3 - nTime2) / (nInputs-1), nTimeConnect * MICRO, nTimeConnect * MILLI / nBlocksTotal); CAmount blockReward = nFees + GetBlockSubsidy(pindex->nHeight, m_params.GetConsensus()); if (block.vtx[0]->GetValueOut() > blockReward) { LogPrintf("ERROR: ConnectBlock(): coinbase pays too much (actual=%d vs limit=%d)\n", block.vtx[0]->GetValueOut(), blockReward); return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-cb-amount"); } if (!control.Wait()) { LogPrintf("ERROR: %s: CheckQueue failed\n", __func__); return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "block-validation-failed"); } int64_t nTime4 = GetTimeMicros(); nTimeVerify += nTime4 - nTime2; LogPrint(BCLog::BENCH, " - Verify %u txins: %.2fms (%.3fms/txin) [%.2fs (%.2fms/blk)]\n", nInputs - 1, MILLI * (nTime4 - nTime2), nInputs <= 1 ? 0 : MILLI * (nTime4 - nTime2) / (nInputs-1), nTimeVerify * MICRO, nTimeVerify * MILLI / nBlocksTotal); if (fJustCheck) return true; if (!m_blockman.WriteUndoDataForBlock(blockundo, state, pindex, m_params)) { return false; } int64_t nTime5 = GetTimeMicros(); nTimeUndo += nTime5 - nTime4; LogPrint(BCLog::BENCH, " - Write undo data: %.2fms [%.2fs (%.2fms/blk)]\n", MILLI * (nTime5 - nTime4), nTimeUndo * MICRO, nTimeUndo * MILLI / nBlocksTotal); if (!pindex->IsValid(BLOCK_VALID_SCRIPTS)) { pindex->RaiseValidity(BLOCK_VALID_SCRIPTS); m_blockman.m_dirty_blockindex.insert(pindex); } // add this block to the view's block chain view.SetBestBlock(pindex->GetBlockHash()); int64_t nTime6 = GetTimeMicros(); nTimeIndex += nTime6 - nTime5; LogPrint(BCLog::BENCH, " - Index writing: %.2fms [%.2fs (%.2fms/blk)]\n", MILLI * (nTime6 - nTime5), nTimeIndex * MICRO, nTimeIndex * MILLI / nBlocksTotal); TRACE6(validation, block_connected, block_hash.data(), pindex->nHeight, block.vtx.size(), nInputs, nSigOpsCost, nTime5 - nTimeStart // in microseconds (µs) ); return true; } CoinsCacheSizeState Chainstate::GetCoinsCacheSizeState() { AssertLockHeld(::cs_main); return this->GetCoinsCacheSizeState( m_coinstip_cache_size_bytes, m_mempool ? m_mempool->m_max_size_bytes : 0); } CoinsCacheSizeState Chainstate::GetCoinsCacheSizeState( size_t max_coins_cache_size_bytes, size_t max_mempool_size_bytes) { AssertLockHeld(::cs_main); const int64_t nMempoolUsage = m_mempool ? m_mempool->DynamicMemoryUsage() : 0; int64_t cacheSize = CoinsTip().DynamicMemoryUsage(); int64_t nTotalSpace = max_coins_cache_size_bytes + std::max<int64_t>(int64_t(max_mempool_size_bytes) - nMempoolUsage, 0); //! No need to periodic flush if at least this much space still available. static constexpr int64_t MAX_BLOCK_COINSDB_USAGE_BYTES = 10 * 1024 * 1024; // 10MB int64_t large_threshold = std::max((9 * nTotalSpace) / 10, nTotalSpace - MAX_BLOCK_COINSDB_USAGE_BYTES); if (cacheSize > nTotalSpace) { LogPrintf("Cache size (%s) exceeds total space (%s)\n", cacheSize, nTotalSpace); return CoinsCacheSizeState::CRITICAL; } else if (cacheSize > large_threshold) { return CoinsCacheSizeState::LARGE; } return CoinsCacheSizeState::OK; } bool Chainstate::FlushStateToDisk( BlockValidationState &state, FlushStateMode mode, int nManualPruneHeight) { LOCK(cs_main); assert(this->CanFlushToDisk()); static std::chrono::microseconds nLastWrite{0}; static std::chrono::microseconds nLastFlush{0}; std::set<int> setFilesToPrune; bool full_flush_completed = false; const size_t coins_count = CoinsTip().GetCacheSize(); const size_t coins_mem_usage = CoinsTip().DynamicMemoryUsage(); try { { bool fFlushForPrune = false; bool fDoFullFlush = false; CoinsCacheSizeState cache_state = GetCoinsCacheSizeState(); LOCK(m_blockman.cs_LastBlockFile); if (fPruneMode && (m_blockman.m_check_for_pruning || nManualPruneHeight > 0) && !fReindex) { // make sure we don't prune above any of the prune locks bestblocks // pruning is height-based int last_prune{m_chain.Height()}; // last height we can prune std::optional<std::string> limiting_lock; // prune lock that actually was the limiting factor, only used for logging for (const auto& prune_lock : m_blockman.m_prune_locks) { if (prune_lock.second.height_first == std::numeric_limits<int>::max()) continue; // Remove the buffer and one additional block here to get actual height that is outside of the buffer const int lock_height{prune_lock.second.height_first - PRUNE_LOCK_BUFFER - 1}; last_prune = std::max(1, std::min(last_prune, lock_height)); if (last_prune == lock_height) { limiting_lock = prune_lock.first; } } if (limiting_lock) { LogPrint(BCLog::PRUNE, "%s limited pruning to height %d\n", limiting_lock.value(), last_prune); } if (nManualPruneHeight > 0) { LOG_TIME_MILLIS_WITH_CATEGORY("find files to prune (manual)", BCLog::BENCH); m_blockman.FindFilesToPruneManual(setFilesToPrune, std::min(last_prune, nManualPruneHeight), m_chain.Height()); } else { LOG_TIME_MILLIS_WITH_CATEGORY("find files to prune", BCLog::BENCH); m_blockman.FindFilesToPrune(setFilesToPrune, m_params.PruneAfterHeight(), m_chain.Height(), last_prune, IsInitialBlockDownload()); m_blockman.m_check_for_pruning = false; } if (!setFilesToPrune.empty()) { fFlushForPrune = true; if (!m_blockman.m_have_pruned) { m_blockman.m_block_tree_db->WriteFlag("prunedblockfiles", true); m_blockman.m_have_pruned = true; } } } const auto nNow = GetTime<std::chrono::microseconds>(); // Avoid writing/flushing immediately after startup. if (nLastWrite.count() == 0) { nLastWrite = nNow; } if (nLastFlush.count() == 0) { nLastFlush = nNow; } // The cache is large and we're within 10% and 10 MiB of the limit, but we have time now (not in the middle of a block processing). bool fCacheLarge = mode == FlushStateMode::PERIODIC && cache_state >= CoinsCacheSizeState::LARGE; // The cache is over the limit, we have to write now. bool fCacheCritical = mode == FlushStateMode::IF_NEEDED && cache_state >= CoinsCacheSizeState::CRITICAL; // It's been a while since we wrote the block index to disk. Do this frequently, so we don't need to redownload after a crash. bool fPeriodicWrite = mode == FlushStateMode::PERIODIC && nNow > nLastWrite + DATABASE_WRITE_INTERVAL; // It's been very long since we flushed the cache. Do this infrequently, to optimize cache usage. bool fPeriodicFlush = mode == FlushStateMode::PERIODIC && nNow > nLastFlush + DATABASE_FLUSH_INTERVAL; // Combine all conditions that result in a full cache flush. fDoFullFlush = (mode == FlushStateMode::ALWAYS) || fCacheLarge || fCacheCritical || fPeriodicFlush || fFlushForPrune; // Write blocks and block index to disk. if (fDoFullFlush || fPeriodicWrite) { // Ensure we can write block index if (!CheckDiskSpace(gArgs.GetBlocksDirPath())) { return AbortNode(state, "Disk space is too low!", _("Disk space is too low!")); } { LOG_TIME_MILLIS_WITH_CATEGORY("write block and undo data to disk", BCLog::BENCH); // First make sure all block and undo data is flushed to disk. m_blockman.FlushBlockFile(); } // Then update all block file information (which may refer to block and undo files). { LOG_TIME_MILLIS_WITH_CATEGORY("write block index to disk", BCLog::BENCH); if (!m_blockman.WriteBlockIndexDB()) { return AbortNode(state, "Failed to write to block index database"); } } // Finally remove any pruned files if (fFlushForPrune) { LOG_TIME_MILLIS_WITH_CATEGORY("unlink pruned files", BCLog::BENCH); UnlinkPrunedFiles(setFilesToPrune); } nLastWrite = nNow; } // Flush best chain related state. This can only be done if the blocks / block index write was also done. if (fDoFullFlush && !CoinsTip().GetBestBlock().IsNull()) { LOG_TIME_MILLIS_WITH_CATEGORY(strprintf("write coins cache to disk (%d coins, %.2fkB)", coins_count, coins_mem_usage / 1000), BCLog::BENCH); // Typical Coin structures on disk are around 48 bytes in size. // Pushing a new one to the database can cause it to be written // twice (once in the log, and once in the tables). This is already // an overestimation, as most will delete an existing entry or // overwrite one. Still, use a conservative safety factor of 2. if (!CheckDiskSpace(gArgs.GetDataDirNet(), 48 * 2 * 2 * CoinsTip().GetCacheSize())) { return AbortNode(state, "Disk space is too low!", _("Disk space is too low!")); } // Flush the chainstate (which may refer to block index entries). if (!CoinsTip().Flush()) return AbortNode(state, "Failed to write to coin database"); nLastFlush = nNow; full_flush_completed = true; TRACE5(utxocache, flush, (int64_t)(GetTimeMicros() - nNow.count()), // in microseconds (µs) (uint32_t)mode, (uint64_t)coins_count, (uint64_t)coins_mem_usage, (bool)fFlushForPrune); } } if (full_flush_completed) { // Update best block in wallet (so we can detect restored wallets). GetMainSignals().ChainStateFlushed(m_chain.GetLocator()); } } catch (const std::runtime_error& e) { return AbortNode(state, std::string("System error while flushing: ") + e.what()); } return true; } void Chainstate::ForceFlushStateToDisk() { BlockValidationState state; if (!this->FlushStateToDisk(state, FlushStateMode::ALWAYS)) { LogPrintf("%s: failed to flush state (%s)\n", __func__, state.ToString()); } } void Chainstate::PruneAndFlush() { BlockValidationState state; m_blockman.m_check_for_pruning = true; if (!this->FlushStateToDisk(state, FlushStateMode::NONE)) { LogPrintf("%s: failed to flush state (%s)\n", __func__, state.ToString()); } } static void DoWarning(const bilingual_str& warning) { static bool fWarned = false; SetMiscWarning(warning); if (!fWarned) { AlertNotify(warning.original); fWarned = true; } } /** Private helper function that concatenates warning messages. */ static void AppendWarning(bilingual_str& res, const bilingual_str& warn) { if (!res.empty()) res += Untranslated(", "); res += warn; } static void UpdateTipLog( const CCoinsViewCache& coins_tip, const CBlockIndex* tip, const CChainParams& params, const std::string& func_name, const std::string& prefix, const std::string& warning_messages) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); LogPrintf("%s%s: new best=%s height=%d version=0x%08x log2_work=%f tx=%lu date='%s' progress=%f cache=%.1fMiB(%utxo)%s\n", prefix, func_name, tip->GetBlockHash().ToString(), tip->nHeight, tip->nVersion, log(tip->nChainWork.getdouble()) / log(2.0), (unsigned long)tip->nChainTx, FormatISO8601DateTime(tip->GetBlockTime()), GuessVerificationProgress(params.TxData(), tip), coins_tip.DynamicMemoryUsage() * (1.0 / (1 << 20)), coins_tip.GetCacheSize(), !warning_messages.empty() ? strprintf(" warning='%s'", warning_messages) : ""); } void Chainstate::UpdateTip(const CBlockIndex* pindexNew) { AssertLockHeld(::cs_main); const auto& coins_tip = this->CoinsTip(); // The remainder of the function isn't relevant if we are not acting on // the active chainstate, so return if need be. if (this != &m_chainman.ActiveChainstate()) { // Only log every so often so that we don't bury log messages at the tip. constexpr int BACKGROUND_LOG_INTERVAL = 2000; if (pindexNew->nHeight % BACKGROUND_LOG_INTERVAL == 0) { UpdateTipLog(coins_tip, pindexNew, m_params, __func__, "[background validation] ", ""); } return; } // New best block if (m_mempool) { m_mempool->AddTransactionsUpdated(1); } { LOCK(g_best_block_mutex); g_best_block = pindexNew->GetBlockHash(); g_best_block_cv.notify_all(); } bilingual_str warning_messages; if (!this->IsInitialBlockDownload()) { const CBlockIndex* pindex = pindexNew; for (int bit = 0; bit < VERSIONBITS_NUM_BITS; bit++) { WarningBitsConditionChecker checker(m_chainman, bit); ThresholdState state = checker.GetStateFor(pindex, m_params.GetConsensus(), warningcache.at(bit)); if (state == ThresholdState::ACTIVE || state == ThresholdState::LOCKED_IN) { const bilingual_str warning = strprintf(_("Unknown new rules activated (versionbit %i)"), bit); if (state == ThresholdState::ACTIVE) { DoWarning(warning); } else { AppendWarning(warning_messages, warning); } } } } UpdateTipLog(coins_tip, pindexNew, m_params, __func__, "", warning_messages.original); } /** Disconnect m_chain's tip. * After calling, the mempool will be in an inconsistent state, with * transactions from disconnected blocks being added to disconnectpool. You * should make the mempool consistent again by calling MaybeUpdateMempoolForReorg. * with cs_main held. * * If disconnectpool is nullptr, then no disconnected transactions are added to * disconnectpool (note that the caller is responsible for mempool consistency * in any case). */ bool Chainstate::DisconnectTip(BlockValidationState& state, DisconnectedBlockTransactions* disconnectpool) { AssertLockHeld(cs_main); if (m_mempool) AssertLockHeld(m_mempool->cs); CBlockIndex *pindexDelete = m_chain.Tip(); assert(pindexDelete); assert(pindexDelete->pprev); // Read block from disk. std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>(); CBlock& block = *pblock; if (!ReadBlockFromDisk(block, pindexDelete, m_params.GetConsensus())) { return error("DisconnectTip(): Failed to read block"); } // Apply the block atomically to the chain state. int64_t nStart = GetTimeMicros(); { CCoinsViewCache view(&CoinsTip()); assert(view.GetBestBlock() == pindexDelete->GetBlockHash()); if (DisconnectBlock(block, pindexDelete, view) != DISCONNECT_OK) return error("DisconnectTip(): DisconnectBlock %s failed", pindexDelete->GetBlockHash().ToString()); bool flushed = view.Flush(); assert(flushed); } LogPrint(BCLog::BENCH, "- Disconnect block: %.2fms\n", (GetTimeMicros() - nStart) * MILLI); { // Prune locks that began at or after the tip should be moved backward so they get a chance to reorg const int max_height_first{pindexDelete->nHeight - 1}; for (auto& prune_lock : m_blockman.m_prune_locks) { if (prune_lock.second.height_first <= max_height_first) continue; prune_lock.second.height_first = max_height_first; LogPrint(BCLog::PRUNE, "%s prune lock moved back to %d\n", prune_lock.first, max_height_first); } } // Write the chain state to disk, if necessary. if (!FlushStateToDisk(state, FlushStateMode::IF_NEEDED)) { return false; } if (disconnectpool && m_mempool) { // Save transactions to re-add to mempool at end of reorg for (auto it = block.vtx.rbegin(); it != block.vtx.rend(); ++it) { disconnectpool->addTransaction(*it); } while (disconnectpool->DynamicMemoryUsage() > MAX_DISCONNECTED_TX_POOL_SIZE * 1000) { // Drop the earliest entry, and remove its children from the mempool. auto it = disconnectpool->queuedTx.get<insertion_order>().begin(); m_mempool->removeRecursive(**it, MemPoolRemovalReason::REORG); disconnectpool->removeEntry(it); } } m_chain.SetTip(*pindexDelete->pprev); UpdateTip(pindexDelete->pprev); // Let wallets know transactions went from 1-confirmed to // 0-confirmed or conflicted: GetMainSignals().BlockDisconnected(pblock, pindexDelete); return true; } static int64_t nTimeReadFromDiskTotal = 0; static int64_t nTimeConnectTotal = 0; static int64_t nTimeFlush = 0; static int64_t nTimeChainState = 0; static int64_t nTimePostConnect = 0; struct PerBlockConnectTrace { CBlockIndex* pindex = nullptr; std::shared_ptr<const CBlock> pblock; PerBlockConnectTrace() = default; }; /** * Used to track blocks whose transactions were applied to the UTXO state as a * part of a single ActivateBestChainStep call. * * This class is single-use, once you call GetBlocksConnected() you have to throw * it away and make a new one. */ class ConnectTrace { private: std::vector<PerBlockConnectTrace> blocksConnected; public: explicit ConnectTrace() : blocksConnected(1) {} void BlockConnected(CBlockIndex* pindex, std::shared_ptr<const CBlock> pblock) { assert(!blocksConnected.back().pindex); assert(pindex); assert(pblock); blocksConnected.back().pindex = pindex; blocksConnected.back().pblock = std::move(pblock); blocksConnected.emplace_back(); } std::vector<PerBlockConnectTrace>& GetBlocksConnected() { // We always keep one extra block at the end of our list because // blocks are added after all the conflicted transactions have // been filled in. Thus, the last entry should always be an empty // one waiting for the transactions from the next block. We pop // the last entry here to make sure the list we return is sane. assert(!blocksConnected.back().pindex); blocksConnected.pop_back(); return blocksConnected; } }; /** * Connect a new block to m_chain. pblock is either nullptr or a pointer to a CBlock * corresponding to pindexNew, to bypass loading it again from disk. * * The block is added to connectTrace if connection succeeds. */ bool Chainstate::ConnectTip(BlockValidationState& state, CBlockIndex* pindexNew, const std::shared_ptr<const CBlock>& pblock, ConnectTrace& connectTrace, DisconnectedBlockTransactions& disconnectpool) { AssertLockHeld(cs_main); if (m_mempool) AssertLockHeld(m_mempool->cs); assert(pindexNew->pprev == m_chain.Tip()); // Read block from disk. int64_t nTime1 = GetTimeMicros(); std::shared_ptr<const CBlock> pthisBlock; if (!pblock) { std::shared_ptr<CBlock> pblockNew = std::make_shared<CBlock>(); if (!ReadBlockFromDisk(*pblockNew, pindexNew, m_params.GetConsensus())) { return AbortNode(state, "Failed to read block"); } pthisBlock = pblockNew; } else { LogPrint(BCLog::BENCH, " - Using cached block\n"); pthisBlock = pblock; } const CBlock& blockConnecting = *pthisBlock; // Apply the block atomically to the chain state. int64_t nTime2 = GetTimeMicros(); nTimeReadFromDiskTotal += nTime2 - nTime1; int64_t nTime3; LogPrint(BCLog::BENCH, " - Load block from disk: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime2 - nTime1) * MILLI, nTimeReadFromDiskTotal * MICRO, nTimeReadFromDiskTotal * MILLI / nBlocksTotal); { CCoinsViewCache view(&CoinsTip()); bool rv = ConnectBlock(blockConnecting, state, pindexNew, view); GetMainSignals().BlockChecked(blockConnecting, state); if (!rv) { if (state.IsInvalid()) InvalidBlockFound(pindexNew, state); return error("%s: ConnectBlock %s failed, %s", __func__, pindexNew->GetBlockHash().ToString(), state.ToString()); } nTime3 = GetTimeMicros(); nTimeConnectTotal += nTime3 - nTime2; assert(nBlocksTotal > 0); LogPrint(BCLog::BENCH, " - Connect total: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime3 - nTime2) * MILLI, nTimeConnectTotal * MICRO, nTimeConnectTotal * MILLI / nBlocksTotal); bool flushed = view.Flush(); assert(flushed); } int64_t nTime4 = GetTimeMicros(); nTimeFlush += nTime4 - nTime3; LogPrint(BCLog::BENCH, " - Flush: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime4 - nTime3) * MILLI, nTimeFlush * MICRO, nTimeFlush * MILLI / nBlocksTotal); // Write the chain state to disk, if necessary. if (!FlushStateToDisk(state, FlushStateMode::IF_NEEDED)) { return false; } int64_t nTime5 = GetTimeMicros(); nTimeChainState += nTime5 - nTime4; LogPrint(BCLog::BENCH, " - Writing chainstate: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime5 - nTime4) * MILLI, nTimeChainState * MICRO, nTimeChainState * MILLI / nBlocksTotal); // Remove conflicting transactions from the mempool.; if (m_mempool) { m_mempool->removeForBlock(blockConnecting.vtx, pindexNew->nHeight); disconnectpool.removeForBlock(blockConnecting.vtx); } // Update m_chain & related variables. m_chain.SetTip(*pindexNew); UpdateTip(pindexNew); int64_t nTime6 = GetTimeMicros(); nTimePostConnect += nTime6 - nTime5; nTimeTotal += nTime6 - nTime1; LogPrint(BCLog::BENCH, " - Connect postprocess: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime6 - nTime5) * MILLI, nTimePostConnect * MICRO, nTimePostConnect * MILLI / nBlocksTotal); LogPrint(BCLog::BENCH, "- Connect block: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime6 - nTime1) * MILLI, nTimeTotal * MICRO, nTimeTotal * MILLI / nBlocksTotal); connectTrace.BlockConnected(pindexNew, std::move(pthisBlock)); return true; } /** * Return the tip of the chain with the most work in it, that isn't * known to be invalid (it's however far from certain to be valid). */ CBlockIndex* Chainstate::FindMostWorkChain() { AssertLockHeld(::cs_main); do { CBlockIndex *pindexNew = nullptr; // Find the best candidate header. { std::set<CBlockIndex*, CBlockIndexWorkComparator>::reverse_iterator it = setBlockIndexCandidates.rbegin(); if (it == setBlockIndexCandidates.rend()) return nullptr; pindexNew = *it; } // Check whether all blocks on the path between the currently active chain and the candidate are valid. // Just going until the active chain is an optimization, as we know all blocks in it are valid already. CBlockIndex *pindexTest = pindexNew; bool fInvalidAncestor = false; while (pindexTest && !m_chain.Contains(pindexTest)) { assert(pindexTest->HaveTxsDownloaded() || pindexTest->nHeight == 0); // Pruned nodes may have entries in setBlockIndexCandidates for // which block files have been deleted. Remove those as candidates // for the most work chain if we come across them; we can't switch // to a chain unless we have all the non-active-chain parent blocks. bool fFailedChain = pindexTest->nStatus & BLOCK_FAILED_MASK; bool fMissingData = !(pindexTest->nStatus & BLOCK_HAVE_DATA); if (fFailedChain || fMissingData) { // Candidate chain is not usable (either invalid or missing data) if (fFailedChain && (m_chainman.m_best_invalid == nullptr || pindexNew->nChainWork > m_chainman.m_best_invalid->nChainWork)) { m_chainman.m_best_invalid = pindexNew; } CBlockIndex *pindexFailed = pindexNew; // Remove the entire chain from the set. while (pindexTest != pindexFailed) { if (fFailedChain) { pindexFailed->nStatus |= BLOCK_FAILED_CHILD; } else if (fMissingData) { // If we're missing data, then add back to m_blocks_unlinked, // so that if the block arrives in the future we can try adding // to setBlockIndexCandidates again. m_blockman.m_blocks_unlinked.insert( std::make_pair(pindexFailed->pprev, pindexFailed)); } setBlockIndexCandidates.erase(pindexFailed); pindexFailed = pindexFailed->pprev; } setBlockIndexCandidates.erase(pindexTest); fInvalidAncestor = true; break; } pindexTest = pindexTest->pprev; } if (!fInvalidAncestor) return pindexNew; } while(true); } /** Delete all entries in setBlockIndexCandidates that are worse than the current tip. */ void Chainstate::PruneBlockIndexCandidates() { // Note that we can't delete the current block itself, as we may need to return to it later in case a // reorganization to a better block fails. std::set<CBlockIndex*, CBlockIndexWorkComparator>::iterator it = setBlockIndexCandidates.begin(); while (it != setBlockIndexCandidates.end() && setBlockIndexCandidates.value_comp()(*it, m_chain.Tip())) { setBlockIndexCandidates.erase(it++); } // Either the current tip or a successor of it we're working towards is left in setBlockIndexCandidates. assert(!setBlockIndexCandidates.empty()); } /** * Try to make some progress towards making pindexMostWork the active block. * pblock is either nullptr or a pointer to a CBlock corresponding to pindexMostWork. * * @returns true unless a system error occurred */ bool Chainstate::ActivateBestChainStep(BlockValidationState& state, CBlockIndex* pindexMostWork, const std::shared_ptr<const CBlock>& pblock, bool& fInvalidFound, ConnectTrace& connectTrace) { AssertLockHeld(cs_main); if (m_mempool) AssertLockHeld(m_mempool->cs); const CBlockIndex* pindexOldTip = m_chain.Tip(); const CBlockIndex* pindexFork = m_chain.FindFork(pindexMostWork); // Disconnect active blocks which are no longer in the best chain. bool fBlocksDisconnected = false; DisconnectedBlockTransactions disconnectpool; while (m_chain.Tip() && m_chain.Tip() != pindexFork) { if (!DisconnectTip(state, &disconnectpool)) { // This is likely a fatal error, but keep the mempool consistent, // just in case. Only remove from the mempool in this case. MaybeUpdateMempoolForReorg(disconnectpool, false); // If we're unable to disconnect a block during normal operation, // then that is a failure of our local system -- we should abort // rather than stay on a less work chain. AbortNode(state, "Failed to disconnect block; see debug.log for details"); return false; } fBlocksDisconnected = true; } // Build list of new blocks to connect (in descending height order). std::vector<CBlockIndex*> vpindexToConnect; bool fContinue = true; int nHeight = pindexFork ? pindexFork->nHeight : -1; while (fContinue && nHeight != pindexMostWork->nHeight) { // Don't iterate the entire list of potential improvements toward the best tip, as we likely only need // a few blocks along the way. int nTargetHeight = std::min(nHeight + 32, pindexMostWork->nHeight); vpindexToConnect.clear(); vpindexToConnect.reserve(nTargetHeight - nHeight); CBlockIndex* pindexIter = pindexMostWork->GetAncestor(nTargetHeight); while (pindexIter && pindexIter->nHeight != nHeight) { vpindexToConnect.push_back(pindexIter); pindexIter = pindexIter->pprev; } nHeight = nTargetHeight; // Connect new blocks. for (CBlockIndex* pindexConnect : reverse_iterate(vpindexToConnect)) { if (!ConnectTip(state, pindexConnect, pindexConnect == pindexMostWork ? pblock : std::shared_ptr<const CBlock>(), connectTrace, disconnectpool)) { if (state.IsInvalid()) { // The block violates a consensus rule. if (state.GetResult() != BlockValidationResult::BLOCK_MUTATED) { InvalidChainFound(vpindexToConnect.front()); } state = BlockValidationState(); fInvalidFound = true; fContinue = false; break; } else { // A system error occurred (disk space, database error, ...). // Make the mempool consistent with the current tip, just in case // any observers try to use it before shutdown. MaybeUpdateMempoolForReorg(disconnectpool, false); return false; } } else { PruneBlockIndexCandidates(); if (!pindexOldTip || m_chain.Tip()->nChainWork > pindexOldTip->nChainWork) { // We're in a better position than we were. Return temporarily to release the lock. fContinue = false; break; } } } } if (fBlocksDisconnected) { // If any blocks were disconnected, disconnectpool may be non empty. Add // any disconnected transactions back to the mempool. MaybeUpdateMempoolForReorg(disconnectpool, true); } if (m_mempool) m_mempool->check(this->CoinsTip(), this->m_chain.Height() + 1); CheckForkWarningConditions(); return true; } static SynchronizationState GetSynchronizationState(bool init) { if (!init) return SynchronizationState::POST_INIT; if (::fReindex) return SynchronizationState::INIT_REINDEX; return SynchronizationState::INIT_DOWNLOAD; } static bool NotifyHeaderTip(Chainstate& chainstate) LOCKS_EXCLUDED(cs_main) { bool fNotify = false; bool fInitialBlockDownload = false; static CBlockIndex* pindexHeaderOld = nullptr; CBlockIndex* pindexHeader = nullptr; { LOCK(cs_main); pindexHeader = chainstate.m_chainman.m_best_header; if (pindexHeader != pindexHeaderOld) { fNotify = true; fInitialBlockDownload = chainstate.IsInitialBlockDownload(); pindexHeaderOld = pindexHeader; } } // Send block tip changed notifications without cs_main if (fNotify) { uiInterface.NotifyHeaderTip(GetSynchronizationState(fInitialBlockDownload), pindexHeader->nHeight, pindexHeader->nTime, false); } return fNotify; } static void LimitValidationInterfaceQueue() LOCKS_EXCLUDED(cs_main) { AssertLockNotHeld(cs_main); if (GetMainSignals().CallbacksPending() > 10) { SyncWithValidationInterfaceQueue(); } } bool Chainstate::ActivateBestChain(BlockValidationState& state, std::shared_ptr<const CBlock> pblock) { AssertLockNotHeld(m_chainstate_mutex); // Note that while we're often called here from ProcessNewBlock, this is // far from a guarantee. Things in the P2P/RPC will often end up calling // us in the middle of ProcessNewBlock - do not assume pblock is set // sanely for performance or correctness! AssertLockNotHeld(::cs_main); // ABC maintains a fair degree of expensive-to-calculate internal state // because this function periodically releases cs_main so that it does not lock up other threads for too long // during large connects - and to allow for e.g. the callback queue to drain // we use m_chainstate_mutex to enforce mutual exclusion so that only one caller may execute this function at a time LOCK(m_chainstate_mutex); CBlockIndex *pindexMostWork = nullptr; CBlockIndex *pindexNewTip = nullptr; int nStopAtHeight = gArgs.GetIntArg("-stopatheight", DEFAULT_STOPATHEIGHT); do { // Block until the validation queue drains. This should largely // never happen in normal operation, however may happen during // reindex, causing memory blowup if we run too far ahead. // Note that if a validationinterface callback ends up calling // ActivateBestChain this may lead to a deadlock! We should // probably have a DEBUG_LOCKORDER test for this in the future. LimitValidationInterfaceQueue(); { LOCK(cs_main); // Lock transaction pool for at least as long as it takes for connectTrace to be consumed LOCK(MempoolMutex()); CBlockIndex* starting_tip = m_chain.Tip(); bool blocks_connected = false; do { // We absolutely may not unlock cs_main until we've made forward progress // (with the exception of shutdown due to hardware issues, low disk space, etc). ConnectTrace connectTrace; // Destructed before cs_main is unlocked if (pindexMostWork == nullptr) { pindexMostWork = FindMostWorkChain(); } // Whether we have anything to do at all. if (pindexMostWork == nullptr || pindexMostWork == m_chain.Tip()) { break; } bool fInvalidFound = false; std::shared_ptr<const CBlock> nullBlockPtr; if (!ActivateBestChainStep(state, pindexMostWork, pblock && pblock->GetHash() == pindexMostWork->GetBlockHash() ? pblock : nullBlockPtr, fInvalidFound, connectTrace)) { // A system error occurred return false; } blocks_connected = true; if (fInvalidFound) { // Wipe cache, we may need another branch now. pindexMostWork = nullptr; } pindexNewTip = m_chain.Tip(); for (const PerBlockConnectTrace& trace : connectTrace.GetBlocksConnected()) { assert(trace.pblock && trace.pindex); GetMainSignals().BlockConnected(trace.pblock, trace.pindex); } } while (!m_chain.Tip() || (starting_tip && CBlockIndexWorkComparator()(m_chain.Tip(), starting_tip))); if (!blocks_connected) return true; const CBlockIndex* pindexFork = m_chain.FindFork(starting_tip); bool fInitialDownload = IsInitialBlockDownload(); // Notify external listeners about the new tip. // Enqueue while holding cs_main to ensure that UpdatedBlockTip is called in the order in which blocks are connected if (pindexFork != pindexNewTip) { // Notify ValidationInterface subscribers GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork, fInitialDownload); // Always notify the UI if a new block tip was connected uiInterface.NotifyBlockTip(GetSynchronizationState(fInitialDownload), pindexNewTip); } } // When we reach this point, we switched to a new tip (stored in pindexNewTip). if (nStopAtHeight && pindexNewTip && pindexNewTip->nHeight >= nStopAtHeight) StartShutdown(); // We check shutdown only after giving ActivateBestChainStep a chance to run once so that we // never shutdown before connecting the genesis block during LoadChainTip(). Previously this // caused an assert() failure during shutdown in such cases as the UTXO DB flushing checks // that the best block hash is non-null. if (ShutdownRequested()) break; } while (pindexNewTip != pindexMostWork); CheckBlockIndex(); // Write changes periodically to disk, after relay. if (!FlushStateToDisk(state, FlushStateMode::PERIODIC)) { return false; } return true; } bool Chainstate::PreciousBlock(BlockValidationState& state, CBlockIndex* pindex) { AssertLockNotHeld(m_chainstate_mutex); AssertLockNotHeld(::cs_main); { LOCK(cs_main); if (pindex->nChainWork < m_chain.Tip()->nChainWork) { // Nothing to do, this block is not at the tip. return true; } if (m_chain.Tip()->nChainWork > nLastPreciousChainwork) { // The chain has been extended since the last call, reset the counter. nBlockReverseSequenceId = -1; } nLastPreciousChainwork = m_chain.Tip()->nChainWork; setBlockIndexCandidates.erase(pindex); pindex->nSequenceId = nBlockReverseSequenceId; if (nBlockReverseSequenceId > std::numeric_limits<int32_t>::min()) { // We can't keep reducing the counter if somebody really wants to // call preciousblock 2**31-1 times on the same set of tips... nBlockReverseSequenceId--; } if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && pindex->HaveTxsDownloaded()) { setBlockIndexCandidates.insert(pindex); PruneBlockIndexCandidates(); } } return ActivateBestChain(state, std::shared_ptr<const CBlock>()); } bool Chainstate::InvalidateBlock(BlockValidationState& state, CBlockIndex* pindex) { AssertLockNotHeld(m_chainstate_mutex); AssertLockNotHeld(::cs_main); // Genesis block can't be invalidated assert(pindex); if (pindex->nHeight == 0) return false; CBlockIndex* to_mark_failed = pindex; bool pindex_was_in_chain = false; int disconnected = 0; // We do not allow ActivateBestChain() to run while InvalidateBlock() is // running, as that could cause the tip to change while we disconnect // blocks. LOCK(m_chainstate_mutex); // We'll be acquiring and releasing cs_main below, to allow the validation // callbacks to run. However, we should keep the block index in a // consistent state as we disconnect blocks -- in particular we need to // add equal-work blocks to setBlockIndexCandidates as we disconnect. // To avoid walking the block index repeatedly in search of candidates, // build a map once so that we can look up candidate blocks by chain // work as we go. std::multimap<const arith_uint256, CBlockIndex *> candidate_blocks_by_work; { LOCK(cs_main); for (auto& entry : m_blockman.m_block_index) { CBlockIndex* candidate = &entry.second; // We don't need to put anything in our active chain into the // multimap, because those candidates will be found and considered // as we disconnect. // Instead, consider only non-active-chain blocks that have at // least as much work as where we expect the new tip to end up. if (!m_chain.Contains(candidate) && !CBlockIndexWorkComparator()(candidate, pindex->pprev) && candidate->IsValid(BLOCK_VALID_TRANSACTIONS) && candidate->HaveTxsDownloaded()) { candidate_blocks_by_work.insert(std::make_pair(candidate->nChainWork, candidate)); } } } // Disconnect (descendants of) pindex, and mark them invalid. while (true) { if (ShutdownRequested()) break; // Make sure the queue of validation callbacks doesn't grow unboundedly. LimitValidationInterfaceQueue(); LOCK(cs_main); // Lock for as long as disconnectpool is in scope to make sure MaybeUpdateMempoolForReorg is // called after DisconnectTip without unlocking in between LOCK(MempoolMutex()); if (!m_chain.Contains(pindex)) break; pindex_was_in_chain = true; CBlockIndex *invalid_walk_tip = m_chain.Tip(); // ActivateBestChain considers blocks already in m_chain // unconditionally valid already, so force disconnect away from it. DisconnectedBlockTransactions disconnectpool; bool ret = DisconnectTip(state, &disconnectpool); // DisconnectTip will add transactions to disconnectpool. // Adjust the mempool to be consistent with the new tip, adding // transactions back to the mempool if disconnecting was successful, // and we're not doing a very deep invalidation (in which case // keeping the mempool up to date is probably futile anyway). MaybeUpdateMempoolForReorg(disconnectpool, /* fAddToMempool = */ (++disconnected <= 10) && ret); if (!ret) return false; assert(invalid_walk_tip->pprev == m_chain.Tip()); // We immediately mark the disconnected blocks as invalid. // This prevents a case where pruned nodes may fail to invalidateblock // and be left unable to start as they have no tip candidates (as there // are no blocks that meet the "have data and are not invalid per // nStatus" criteria for inclusion in setBlockIndexCandidates). invalid_walk_tip->nStatus |= BLOCK_FAILED_VALID; m_blockman.m_dirty_blockindex.insert(invalid_walk_tip); setBlockIndexCandidates.erase(invalid_walk_tip); setBlockIndexCandidates.insert(invalid_walk_tip->pprev); if (invalid_walk_tip->pprev == to_mark_failed && (to_mark_failed->nStatus & BLOCK_FAILED_VALID)) { // We only want to mark the last disconnected block as BLOCK_FAILED_VALID; its children // need to be BLOCK_FAILED_CHILD instead. to_mark_failed->nStatus = (to_mark_failed->nStatus ^ BLOCK_FAILED_VALID) | BLOCK_FAILED_CHILD; m_blockman.m_dirty_blockindex.insert(to_mark_failed); } // Add any equal or more work headers to setBlockIndexCandidates auto candidate_it = candidate_blocks_by_work.lower_bound(invalid_walk_tip->pprev->nChainWork); while (candidate_it != candidate_blocks_by_work.end()) { if (!CBlockIndexWorkComparator()(candidate_it->second, invalid_walk_tip->pprev)) { setBlockIndexCandidates.insert(candidate_it->second); candidate_it = candidate_blocks_by_work.erase(candidate_it); } else { ++candidate_it; } } // Track the last disconnected block, so we can correct its BLOCK_FAILED_CHILD status in future // iterations, or, if it's the last one, call InvalidChainFound on it. to_mark_failed = invalid_walk_tip; } CheckBlockIndex(); { LOCK(cs_main); if (m_chain.Contains(to_mark_failed)) { // If the to-be-marked invalid block is in the active chain, something is interfering and we can't proceed. return false; } // Mark pindex (or the last disconnected block) as invalid, even when it never was in the main chain to_mark_failed->nStatus |= BLOCK_FAILED_VALID; m_blockman.m_dirty_blockindex.insert(to_mark_failed); setBlockIndexCandidates.erase(to_mark_failed); m_chainman.m_failed_blocks.insert(to_mark_failed); // If any new blocks somehow arrived while we were disconnecting // (above), then the pre-calculation of what should go into // setBlockIndexCandidates may have missed entries. This would // technically be an inconsistency in the block index, but if we clean // it up here, this should be an essentially unobservable error. // Loop back over all block index entries and add any missing entries // to setBlockIndexCandidates. for (auto& [_, block_index] : m_blockman.m_block_index) { if (block_index.IsValid(BLOCK_VALID_TRANSACTIONS) && block_index.HaveTxsDownloaded() && !setBlockIndexCandidates.value_comp()(&block_index, m_chain.Tip())) { setBlockIndexCandidates.insert(&block_index); } } InvalidChainFound(to_mark_failed); } // Only notify about a new block tip if the active chain was modified. if (pindex_was_in_chain) { uiInterface.NotifyBlockTip(GetSynchronizationState(IsInitialBlockDownload()), to_mark_failed->pprev); } return true; } void Chainstate::ResetBlockFailureFlags(CBlockIndex *pindex) { AssertLockHeld(cs_main); int nHeight = pindex->nHeight; // Remove the invalidity flag from this block and all its descendants. for (auto& [_, block_index] : m_blockman.m_block_index) { if (!block_index.IsValid() && block_index.GetAncestor(nHeight) == pindex) { block_index.nStatus &= ~BLOCK_FAILED_MASK; m_blockman.m_dirty_blockindex.insert(&block_index); if (block_index.IsValid(BLOCK_VALID_TRANSACTIONS) && block_index.HaveTxsDownloaded() && setBlockIndexCandidates.value_comp()(m_chain.Tip(), &block_index)) { setBlockIndexCandidates.insert(&block_index); } if (&block_index == m_chainman.m_best_invalid) { // Reset invalid block marker if it was pointing to one of those. m_chainman.m_best_invalid = nullptr; } m_chainman.m_failed_blocks.erase(&block_index); } } // Remove the invalidity flag from all ancestors too. while (pindex != nullptr) { if (pindex->nStatus & BLOCK_FAILED_MASK) { pindex->nStatus &= ~BLOCK_FAILED_MASK; m_blockman.m_dirty_blockindex.insert(pindex); m_chainman.m_failed_blocks.erase(pindex); } pindex = pindex->pprev; } } /** Mark a block as having its data received and checked (up to BLOCK_VALID_TRANSACTIONS). */ void Chainstate::ReceivedBlockTransactions(const CBlock& block, CBlockIndex* pindexNew, const FlatFilePos& pos) { AssertLockHeld(cs_main); pindexNew->nTx = block.vtx.size(); pindexNew->nChainTx = 0; pindexNew->nFile = pos.nFile; pindexNew->nDataPos = pos.nPos; pindexNew->nUndoPos = 0; pindexNew->nStatus |= BLOCK_HAVE_DATA; if (DeploymentActiveAt(*pindexNew, m_chainman, Consensus::DEPLOYMENT_SEGWIT)) { pindexNew->nStatus |= BLOCK_OPT_WITNESS; } pindexNew->RaiseValidity(BLOCK_VALID_TRANSACTIONS); m_blockman.m_dirty_blockindex.insert(pindexNew); if (pindexNew->pprev == nullptr || pindexNew->pprev->HaveTxsDownloaded()) { // If pindexNew is the genesis block or all parents are BLOCK_VALID_TRANSACTIONS. std::deque<CBlockIndex*> queue; queue.push_back(pindexNew); // Recursively process any descendant blocks that now may be eligible to be connected. while (!queue.empty()) { CBlockIndex *pindex = queue.front(); queue.pop_front(); pindex->nChainTx = (pindex->pprev ? pindex->pprev->nChainTx : 0) + pindex->nTx; pindex->nSequenceId = nBlockSequenceId++; if (m_chain.Tip() == nullptr || !setBlockIndexCandidates.value_comp()(pindex, m_chain.Tip())) { setBlockIndexCandidates.insert(pindex); } std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> range = m_blockman.m_blocks_unlinked.equal_range(pindex); while (range.first != range.second) { std::multimap<CBlockIndex*, CBlockIndex*>::iterator it = range.first; queue.push_back(it->second); range.first++; m_blockman.m_blocks_unlinked.erase(it); } } } else { if (pindexNew->pprev && pindexNew->pprev->IsValid(BLOCK_VALID_TREE)) { m_blockman.m_blocks_unlinked.insert(std::make_pair(pindexNew->pprev, pindexNew)); } } } static bool CheckBlockHeader(const CBlockHeader& block, BlockValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW = true) { // Check proof of work matches claimed amount if (fCheckPOW && !CheckProofOfWork(block.GetHash(), block.nBits, consensusParams)) return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER, "high-hash", "proof of work failed"); return true; } bool CheckBlock(const CBlock& block, BlockValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW, bool fCheckMerkleRoot) { // These are checks that are independent of context. if (block.fChecked) return true; // Check that the header is valid (particularly PoW). This is mostly // redundant with the call in AcceptBlockHeader. if (!CheckBlockHeader(block, state, consensusParams, fCheckPOW)) return false; // Signet only: check block solution if (consensusParams.signet_blocks && fCheckPOW && !CheckSignetBlockSolution(block, consensusParams)) { return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-signet-blksig", "signet block signature validation failure"); } // Check the merkle root. if (fCheckMerkleRoot) { bool mutated; uint256 hashMerkleRoot2 = BlockMerkleRoot(block, &mutated); if (block.hashMerkleRoot != hashMerkleRoot2) return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-txnmrklroot", "hashMerkleRoot mismatch"); // Check for merkle tree malleability (CVE-2012-2459): repeating sequences // of transactions in a block without affecting the merkle root of a block, // while still invalidating it. if (mutated) return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-txns-duplicate", "duplicate transaction"); } // All potential-corruption validation must be done before we do any // transaction validation, as otherwise we may mark the header as invalid // because we receive the wrong transactions for it. // Note that witness malleability is checked in ContextualCheckBlock, so no // checks that use witness data may be performed here. // Size limits if (block.vtx.empty() || block.vtx.size() * WITNESS_SCALE_FACTOR > MAX_BLOCK_WEIGHT || ::GetSerializeSize(block, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) * WITNESS_SCALE_FACTOR > MAX_BLOCK_WEIGHT) return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-blk-length", "size limits failed"); // First transaction must be coinbase, the rest must not be if (block.vtx.empty() || !block.vtx[0]->IsCoinBase()) return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-cb-missing", "first tx is not coinbase"); for (unsigned int i = 1; i < block.vtx.size(); i++) if (block.vtx[i]->IsCoinBase()) return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-cb-multiple", "more than one coinbase"); // Check transactions // Must check for duplicate inputs (see CVE-2018-17144) for (const auto& tx : block.vtx) { TxValidationState tx_state; if (!CheckTransaction(*tx, tx_state)) { // CheckBlock() does context-free validation checks. The only // possible failures are consensus failures. assert(tx_state.GetResult() == TxValidationResult::TX_CONSENSUS); return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, tx_state.GetRejectReason(), strprintf("Transaction check failed (tx hash %s) %s", tx->GetHash().ToString(), tx_state.GetDebugMessage())); } } unsigned int nSigOps = 0; for (const auto& tx : block.vtx) { nSigOps += GetLegacySigOpCount(*tx); } if (nSigOps * WITNESS_SCALE_FACTOR > MAX_BLOCK_SIGOPS_COST) return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-blk-sigops", "out-of-bounds SigOpCount"); if (fCheckPOW && fCheckMerkleRoot) block.fChecked = true; return true; } void ChainstateManager::UpdateUncommittedBlockStructures(CBlock& block, const CBlockIndex* pindexPrev) const { int commitpos = GetWitnessCommitmentIndex(block); static const std::vector<unsigned char> nonce(32, 0x00); if (commitpos != NO_WITNESS_COMMITMENT && DeploymentActiveAfter(pindexPrev, *this, Consensus::DEPLOYMENT_SEGWIT) && !block.vtx[0]->HasWitness()) { CMutableTransaction tx(*block.vtx[0]); tx.vin[0].scriptWitness.stack.resize(1); tx.vin[0].scriptWitness.stack[0] = nonce; block.vtx[0] = MakeTransactionRef(std::move(tx)); } } std::vector<unsigned char> ChainstateManager::GenerateCoinbaseCommitment(CBlock& block, const CBlockIndex* pindexPrev) const { std::vector<unsigned char> commitment; int commitpos = GetWitnessCommitmentIndex(block); std::vector<unsigned char> ret(32, 0x00); if (commitpos == NO_WITNESS_COMMITMENT) { uint256 witnessroot = BlockWitnessMerkleRoot(block, nullptr); CHash256().Write(witnessroot).Write(ret).Finalize(witnessroot); CTxOut out; out.nValue = 0; out.scriptPubKey.resize(MINIMUM_WITNESS_COMMITMENT); out.scriptPubKey[0] = OP_RETURN; out.scriptPubKey[1] = 0x24; out.scriptPubKey[2] = 0xaa; out.scriptPubKey[3] = 0x21; out.scriptPubKey[4] = 0xa9; out.scriptPubKey[5] = 0xed; memcpy(&out.scriptPubKey[6], witnessroot.begin(), 32); commitment = std::vector<unsigned char>(out.scriptPubKey.begin(), out.scriptPubKey.end()); CMutableTransaction tx(*block.vtx[0]); tx.vout.push_back(out); block.vtx[0] = MakeTransactionRef(std::move(tx)); } UpdateUncommittedBlockStructures(block, pindexPrev); return commitment; } bool HasValidProofOfWork(const std::vector<CBlockHeader>& headers, const Consensus::Params& consensusParams) { return std::all_of(headers.cbegin(), headers.cend(), [&](const auto& header) { return CheckProofOfWork(header.GetHash(), header.nBits, consensusParams);}); } arith_uint256 CalculateHeadersWork(const std::vector<CBlockHeader>& headers) { arith_uint256 total_work{0}; for (const CBlockHeader& header : headers) { CBlockIndex dummy(header); total_work += GetBlockProof(dummy); } return total_work; } /** Context-dependent validity checks. * By "context", we mean only the previous block headers, but not the UTXO * set; UTXO-related validity checks are done in ConnectBlock(). * NOTE: This function is not currently invoked by ConnectBlock(), so we * should consider upgrade issues if we change which consensus rules are * enforced in this function (eg by adding a new consensus rule). See comment * in ConnectBlock(). * Note that -reindex-chainstate skips the validation that happens here! */ static bool ContextualCheckBlockHeader(const CBlockHeader& block, BlockValidationState& state, BlockManager& blockman, const ChainstateManager& chainman, const CBlockIndex* pindexPrev, NodeClock::time_point now) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); assert(pindexPrev != nullptr); const int nHeight = pindexPrev->nHeight + 1; // Check proof of work const Consensus::Params& consensusParams = chainman.GetConsensus(); if (block.nBits != GetNextWorkRequired(pindexPrev, &block, consensusParams)) return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER, "bad-diffbits", "incorrect proof of work"); // Check against checkpoints if (fCheckpointsEnabled) { // Don't accept any forks from the main chain prior to last checkpoint. // GetLastCheckpoint finds the last checkpoint in MapCheckpoints that's in our // BlockIndex(). const CBlockIndex* pcheckpoint = blockman.GetLastCheckpoint(chainman.GetParams().Checkpoints()); if (pcheckpoint && nHeight < pcheckpoint->nHeight) { LogPrintf("ERROR: %s: forked chain older than last checkpoint (height %d)\n", __func__, nHeight); return state.Invalid(BlockValidationResult::BLOCK_CHECKPOINT, "bad-fork-prior-to-checkpoint"); } } // Check timestamp against prev if (block.GetBlockTime() <= pindexPrev->GetMedianTimePast()) return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER, "time-too-old", "block's timestamp is too early"); // Check timestamp if (block.Time() > now + std::chrono::seconds{MAX_FUTURE_BLOCK_TIME}) { return state.Invalid(BlockValidationResult::BLOCK_TIME_FUTURE, "time-too-new", "block timestamp too far in the future"); } // Reject blocks with outdated version if ((block.nVersion < 2 && DeploymentActiveAfter(pindexPrev, chainman, Consensus::DEPLOYMENT_HEIGHTINCB)) || (block.nVersion < 3 && DeploymentActiveAfter(pindexPrev, chainman, Consensus::DEPLOYMENT_DERSIG)) || (block.nVersion < 4 && DeploymentActiveAfter(pindexPrev, chainman, Consensus::DEPLOYMENT_CLTV))) { return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER, strprintf("bad-version(0x%08x)", block.nVersion), strprintf("rejected nVersion=0x%08x block", block.nVersion)); } return true; } /** NOTE: This function is not currently invoked by ConnectBlock(), so we * should consider upgrade issues if we change which consensus rules are * enforced in this function (eg by adding a new consensus rule). See comment * in ConnectBlock(). * Note that -reindex-chainstate skips the validation that happens here! */ static bool ContextualCheckBlock(const CBlock& block, BlockValidationState& state, const ChainstateManager& chainman, const CBlockIndex* pindexPrev) { const int nHeight = pindexPrev == nullptr ? 0 : pindexPrev->nHeight + 1; // Enforce BIP113 (Median Time Past). bool enforce_locktime_median_time_past{false}; if (DeploymentActiveAfter(pindexPrev, chainman, Consensus::DEPLOYMENT_CSV)) { assert(pindexPrev != nullptr); enforce_locktime_median_time_past = true; } const int64_t nLockTimeCutoff{enforce_locktime_median_time_past ? pindexPrev->GetMedianTimePast() : block.GetBlockTime()}; // Check that all transactions are finalized for (const auto& tx : block.vtx) { if (!IsFinalTx(*tx, nHeight, nLockTimeCutoff)) { return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-txns-nonfinal", "non-final transaction"); } } // Enforce rule that the coinbase starts with serialized block height if (DeploymentActiveAfter(pindexPrev, chainman, Consensus::DEPLOYMENT_HEIGHTINCB)) { CScript expect = CScript() << nHeight; if (block.vtx[0]->vin[0].scriptSig.size() < expect.size() || !std::equal(expect.begin(), expect.end(), block.vtx[0]->vin[0].scriptSig.begin())) { return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-cb-height", "block height mismatch in coinbase"); } } // Validation for witness commitments. // * We compute the witness hash (which is the hash including witnesses) of all the block's transactions, except the // coinbase (where 0x0000....0000 is used instead). // * The coinbase scriptWitness is a stack of a single 32-byte vector, containing a witness reserved value (unconstrained). // * We build a merkle tree with all those witness hashes as leaves (similar to the hashMerkleRoot in the block header). // * There must be at least one output whose scriptPubKey is a single 36-byte push, the first 4 bytes of which are // {0xaa, 0x21, 0xa9, 0xed}, and the following 32 bytes are SHA256^2(witness root, witness reserved value). In case there are // multiple, the last one is used. bool fHaveWitness = false; if (DeploymentActiveAfter(pindexPrev, chainman, Consensus::DEPLOYMENT_SEGWIT)) { int commitpos = GetWitnessCommitmentIndex(block); if (commitpos != NO_WITNESS_COMMITMENT) { bool malleated = false; uint256 hashWitness = BlockWitnessMerkleRoot(block, &malleated); // The malleation check is ignored; as the transaction tree itself // already does not permit it, it is impossible to trigger in the // witness tree. if (block.vtx[0]->vin[0].scriptWitness.stack.size() != 1 || block.vtx[0]->vin[0].scriptWitness.stack[0].size() != 32) { return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-witness-nonce-size", strprintf("%s : invalid witness reserved value size", __func__)); } CHash256().Write(hashWitness).Write(block.vtx[0]->vin[0].scriptWitness.stack[0]).Finalize(hashWitness); if (memcmp(hashWitness.begin(), &block.vtx[0]->vout[commitpos].scriptPubKey[6], 32)) { return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-witness-merkle-match", strprintf("%s : witness merkle commitment mismatch", __func__)); } fHaveWitness = true; } } // No witness data is allowed in blocks that don't commit to witness data, as this would otherwise leave room for spam if (!fHaveWitness) { for (const auto& tx : block.vtx) { if (tx->HasWitness()) { return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "unexpected-witness", strprintf("%s : unexpected witness data found", __func__)); } } } // After the coinbase witness reserved value and commitment are verified, // we can check if the block weight passes (before we've checked the // coinbase witness, it would be possible for the weight to be too // large by filling up the coinbase witness, which doesn't change // the block hash, so we couldn't mark the block as permanently // failed). if (GetBlockWeight(block) > MAX_BLOCK_WEIGHT) { return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-blk-weight", strprintf("%s : weight limit failed", __func__)); } return true; } bool ChainstateManager::AcceptBlockHeader(const CBlockHeader& block, BlockValidationState& state, CBlockIndex** ppindex, bool min_pow_checked) { AssertLockHeld(cs_main); // Check for duplicate uint256 hash = block.GetHash(); BlockMap::iterator miSelf{m_blockman.m_block_index.find(hash)}; if (hash != GetConsensus().hashGenesisBlock) { if (miSelf != m_blockman.m_block_index.end()) { // Block header is already known. CBlockIndex* pindex = &(miSelf->second); if (ppindex) *ppindex = pindex; if (pindex->nStatus & BLOCK_FAILED_MASK) { LogPrint(BCLog::VALIDATION, "%s: block %s is marked invalid\n", __func__, hash.ToString()); return state.Invalid(BlockValidationResult::BLOCK_CACHED_INVALID, "duplicate"); } return true; } if (!CheckBlockHeader(block, state, GetConsensus())) { LogPrint(BCLog::VALIDATION, "%s: Consensus::CheckBlockHeader: %s, %s\n", __func__, hash.ToString(), state.ToString()); return false; } // Get prev block index CBlockIndex* pindexPrev = nullptr; BlockMap::iterator mi{m_blockman.m_block_index.find(block.hashPrevBlock)}; if (mi == m_blockman.m_block_index.end()) { LogPrint(BCLog::VALIDATION, "%s: %s prev block not found\n", __func__, hash.ToString()); return state.Invalid(BlockValidationResult::BLOCK_MISSING_PREV, "prev-blk-not-found"); } pindexPrev = &((*mi).second); if (pindexPrev->nStatus & BLOCK_FAILED_MASK) { LogPrint(BCLog::VALIDATION, "%s: %s prev block invalid\n", __func__, hash.ToString()); return state.Invalid(BlockValidationResult::BLOCK_INVALID_PREV, "bad-prevblk"); } if (!ContextualCheckBlockHeader(block, state, m_blockman, *this, pindexPrev, m_options.adjusted_time_callback())) { LogPrint(BCLog::VALIDATION, "%s: Consensus::ContextualCheckBlockHeader: %s, %s\n", __func__, hash.ToString(), state.ToString()); return false; } /* Determine if this block descends from any block which has been found * invalid (m_failed_blocks), then mark pindexPrev and any blocks between * them as failed. For example: * * D3 * / * B2 - C2 * / \ * A D2 - E2 - F2 * \ * B1 - C1 - D1 - E1 * * In the case that we attempted to reorg from E1 to F2, only to find * C2 to be invalid, we would mark D2, E2, and F2 as BLOCK_FAILED_CHILD * but NOT D3 (it was not in any of our candidate sets at the time). * * In any case D3 will also be marked as BLOCK_FAILED_CHILD at restart * in LoadBlockIndex. */ if (!pindexPrev->IsValid(BLOCK_VALID_SCRIPTS)) { // The above does not mean "invalid": it checks if the previous block // hasn't been validated up to BLOCK_VALID_SCRIPTS. This is a performance // optimization, in the common case of adding a new block to the tip, // we don't need to iterate over the failed blocks list. for (const CBlockIndex* failedit : m_failed_blocks) { if (pindexPrev->GetAncestor(failedit->nHeight) == failedit) { assert(failedit->nStatus & BLOCK_FAILED_VALID); CBlockIndex* invalid_walk = pindexPrev; while (invalid_walk != failedit) { invalid_walk->nStatus |= BLOCK_FAILED_CHILD; m_blockman.m_dirty_blockindex.insert(invalid_walk); invalid_walk = invalid_walk->pprev; } LogPrint(BCLog::VALIDATION, "%s: %s prev block invalid\n", __func__, hash.ToString()); return state.Invalid(BlockValidationResult::BLOCK_INVALID_PREV, "bad-prevblk"); } } } } if (!min_pow_checked) { LogPrint(BCLog::VALIDATION, "%s: not adding new block header %s, missing anti-dos proof-of-work validation\n", __func__, hash.ToString()); return state.Invalid(BlockValidationResult::BLOCK_HEADER_LOW_WORK, "too-little-chainwork"); } CBlockIndex* pindex{m_blockman.AddToBlockIndex(block, m_best_header)}; if (ppindex) *ppindex = pindex; return true; } // Exposed wrapper for AcceptBlockHeader bool ChainstateManager::ProcessNewBlockHeaders(const std::vector<CBlockHeader>& headers, bool min_pow_checked, BlockValidationState& state, const CBlockIndex** ppindex) { AssertLockNotHeld(cs_main); { LOCK(cs_main); for (const CBlockHeader& header : headers) { CBlockIndex *pindex = nullptr; // Use a temp pindex instead of ppindex to avoid a const_cast bool accepted{AcceptBlockHeader(header, state, &pindex, min_pow_checked)}; ActiveChainstate().CheckBlockIndex(); if (!accepted) { return false; } if (ppindex) { *ppindex = pindex; } } } if (NotifyHeaderTip(ActiveChainstate())) { if (ActiveChainstate().IsInitialBlockDownload() && ppindex && *ppindex) { const CBlockIndex& last_accepted{**ppindex}; const int64_t blocks_left{(GetTime() - last_accepted.GetBlockTime()) / GetConsensus().nPowTargetSpacing}; const double progress{100.0 * last_accepted.nHeight / (last_accepted.nHeight + blocks_left)}; LogPrintf("Synchronizing blockheaders, height: %d (~%.2f%%)\n", last_accepted.nHeight, progress); } } return true; } void ChainstateManager::ReportHeadersPresync(const arith_uint256& work, int64_t height, int64_t timestamp) { AssertLockNotHeld(cs_main); const auto& chainstate = ActiveChainstate(); { LOCK(cs_main); // Don't report headers presync progress if we already have a post-minchainwork header chain. // This means we lose reporting for potentially legitimate, but unlikely, deep reorgs, but // prevent attackers that spam low-work headers from filling our logs. if (m_best_header->nChainWork >= UintToArith256(GetConsensus().nMinimumChainWork)) return; // Rate limit headers presync updates to 4 per second, as these are not subject to DoS // protection. auto now = std::chrono::steady_clock::now(); if (now < m_last_presync_update + std::chrono::milliseconds{250}) return; m_last_presync_update = now; } bool initial_download = chainstate.IsInitialBlockDownload(); uiInterface.NotifyHeaderTip(GetSynchronizationState(initial_download), height, timestamp, /*presync=*/true); if (initial_download) { const int64_t blocks_left{(GetTime() - timestamp) / GetConsensus().nPowTargetSpacing}; const double progress{100.0 * height / (height + blocks_left)}; LogPrintf("Pre-synchronizing blockheaders, height: %d (~%.2f%%)\n", height, progress); } } /** Store block on disk. If dbp is non-nullptr, the file is known to already reside on disk */ bool Chainstate::AcceptBlock(const std::shared_ptr<const CBlock>& pblock, BlockValidationState& state, CBlockIndex** ppindex, bool fRequested, const FlatFilePos* dbp, bool* fNewBlock, bool min_pow_checked) { const CBlock& block = *pblock; if (fNewBlock) *fNewBlock = false; AssertLockHeld(cs_main); CBlockIndex *pindexDummy = nullptr; CBlockIndex *&pindex = ppindex ? *ppindex : pindexDummy; bool accepted_header{m_chainman.AcceptBlockHeader(block, state, &pindex, min_pow_checked)}; CheckBlockIndex(); if (!accepted_header) return false; // Try to process all requested blocks that we don't have, but only // process an unrequested block if it's new and has enough work to // advance our tip, and isn't too many blocks ahead. bool fAlreadyHave = pindex->nStatus & BLOCK_HAVE_DATA; bool fHasMoreOrSameWork = (m_chain.Tip() ? pindex->nChainWork >= m_chain.Tip()->nChainWork : true); // Blocks that are too out-of-order needlessly limit the effectiveness of // pruning, because pruning will not delete block files that contain any // blocks which are too close in height to the tip. Apply this test // regardless of whether pruning is enabled; it should generally be safe to // not process unrequested blocks. bool fTooFarAhead{pindex->nHeight > m_chain.Height() + int(MIN_BLOCKS_TO_KEEP)}; // TODO: Decouple this function from the block download logic by removing fRequested // This requires some new chain data structure to efficiently look up if a // block is in a chain leading to a candidate for best tip, despite not // being such a candidate itself. // Note that this would break the getblockfrompeer RPC // TODO: deal better with return value and error conditions for duplicate // and unrequested blocks. if (fAlreadyHave) return true; if (!fRequested) { // If we didn't ask for it: if (pindex->nTx != 0) return true; // This is a previously-processed block that was pruned if (!fHasMoreOrSameWork) return true; // Don't process less-work chains if (fTooFarAhead) return true; // Block height is too high // Protect against DoS attacks from low-work chains. // If our tip is behind, a peer could try to send us // low-work blocks on a fake chain that we would never // request; don't process these. if (pindex->nChainWork < nMinimumChainWork) return true; } if (!CheckBlock(block, state, m_params.GetConsensus()) || !ContextualCheckBlock(block, state, m_chainman, pindex->pprev)) { if (state.IsInvalid() && state.GetResult() != BlockValidationResult::BLOCK_MUTATED) { pindex->nStatus |= BLOCK_FAILED_VALID; m_blockman.m_dirty_blockindex.insert(pindex); } return error("%s: %s", __func__, state.ToString()); } // Header is valid/has work, merkle tree and segwit merkle tree are good...RELAY NOW // (but if it does not build on our best tip, let the SendMessages loop relay it) if (!IsInitialBlockDownload() && m_chain.Tip() == pindex->pprev) GetMainSignals().NewPoWValidBlock(pindex, pblock); // Write block to history file if (fNewBlock) *fNewBlock = true; try { FlatFilePos blockPos{m_blockman.SaveBlockToDisk(block, pindex->nHeight, m_chain, m_params, dbp)}; if (blockPos.IsNull()) { state.Error(strprintf("%s: Failed to find position to write new block to disk", __func__)); return false; } ReceivedBlockTransactions(block, pindex, blockPos); } catch (const std::runtime_error& e) { return AbortNode(state, std::string("System error: ") + e.what()); } FlushStateToDisk(state, FlushStateMode::NONE); CheckBlockIndex(); return true; } bool ChainstateManager::ProcessNewBlock(const std::shared_ptr<const CBlock>& block, bool force_processing, bool min_pow_checked, bool* new_block) { AssertLockNotHeld(cs_main); { CBlockIndex *pindex = nullptr; if (new_block) *new_block = false; BlockValidationState state; // CheckBlock() does not support multi-threaded block validation because CBlock::fChecked can cause data race. // Therefore, the following critical section must include the CheckBlock() call as well. LOCK(cs_main); // Skipping AcceptBlock() for CheckBlock() failures means that we will never mark a block as invalid if // CheckBlock() fails. This is protective against consensus failure if there are any unknown forms of block // malleability that cause CheckBlock() to fail; see e.g. CVE-2012-2459 and // https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2019-February/016697.html. Because CheckBlock() is // not very expensive, the anti-DoS benefits of caching failure (of a definitely-invalid block) are not substantial. bool ret = CheckBlock(*block, state, GetConsensus()); if (ret) { // Store to disk ret = ActiveChainstate().AcceptBlock(block, state, &pindex, force_processing, nullptr, new_block, min_pow_checked); } if (!ret) { GetMainSignals().BlockChecked(*block, state); return error("%s: AcceptBlock FAILED (%s)", __func__, state.ToString()); } } NotifyHeaderTip(ActiveChainstate()); BlockValidationState state; // Only used to report errors, not invalidity - ignore it if (!ActiveChainstate().ActivateBestChain(state, block)) { return error("%s: ActivateBestChain failed (%s)", __func__, state.ToString()); } return true; } MempoolAcceptResult ChainstateManager::ProcessTransaction(const CTransactionRef& tx, bool test_accept) { AssertLockHeld(cs_main); Chainstate& active_chainstate = ActiveChainstate(); if (!active_chainstate.GetMempool()) { TxValidationState state; state.Invalid(TxValidationResult::TX_NO_MEMPOOL, "no-mempool"); return MempoolAcceptResult::Failure(state); } auto result = AcceptToMemoryPool(active_chainstate, tx, GetTime(), /*bypass_limits=*/ false, test_accept); active_chainstate.GetMempool()->check(active_chainstate.CoinsTip(), active_chainstate.m_chain.Height() + 1); return result; } bool TestBlockValidity(BlockValidationState& state, const CChainParams& chainparams, Chainstate& chainstate, const CBlock& block, CBlockIndex* pindexPrev, const std::function<NodeClock::time_point()>& adjusted_time_callback, bool fCheckPOW, bool fCheckMerkleRoot) { AssertLockHeld(cs_main); assert(pindexPrev && pindexPrev == chainstate.m_chain.Tip()); CCoinsViewCache viewNew(&chainstate.CoinsTip()); uint256 block_hash(block.GetHash()); CBlockIndex indexDummy(block); indexDummy.pprev = pindexPrev; indexDummy.nHeight = pindexPrev->nHeight + 1; indexDummy.phashBlock = &block_hash; // NOTE: CheckBlockHeader is called by CheckBlock if (!ContextualCheckBlockHeader(block, state, chainstate.m_blockman, chainstate.m_chainman, pindexPrev, adjusted_time_callback())) return error("%s: Consensus::ContextualCheckBlockHeader: %s", __func__, state.ToString()); if (!CheckBlock(block, state, chainparams.GetConsensus(), fCheckPOW, fCheckMerkleRoot)) return error("%s: Consensus::CheckBlock: %s", __func__, state.ToString()); if (!ContextualCheckBlock(block, state, chainstate.m_chainman, pindexPrev)) return error("%s: Consensus::ContextualCheckBlock: %s", __func__, state.ToString()); if (!chainstate.ConnectBlock(block, state, &indexDummy, viewNew, true)) { return false; } assert(state.IsValid()); return true; } /* This function is called from the RPC code for pruneblockchain */ void PruneBlockFilesManual(Chainstate& active_chainstate, int nManualPruneHeight) { BlockValidationState state; if (!active_chainstate.FlushStateToDisk( state, FlushStateMode::NONE, nManualPruneHeight)) { LogPrintf("%s: failed to flush state (%s)\n", __func__, state.ToString()); } } void Chainstate::LoadMempool(const fs::path& load_path, FopenFn mockable_fopen_function) { if (!m_mempool) return; ::LoadMempool(*m_mempool, load_path, *this, mockable_fopen_function); m_mempool->SetLoadTried(!ShutdownRequested()); } bool Chainstate::LoadChainTip() { AssertLockHeld(cs_main); const CCoinsViewCache& coins_cache = CoinsTip(); assert(!coins_cache.GetBestBlock().IsNull()); // Never called when the coins view is empty const CBlockIndex* tip = m_chain.Tip(); if (tip && tip->GetBlockHash() == coins_cache.GetBestBlock()) { return true; } // Load pointer to end of best chain CBlockIndex* pindex = m_blockman.LookupBlockIndex(coins_cache.GetBestBlock()); if (!pindex) { return false; } m_chain.SetTip(*pindex); PruneBlockIndexCandidates(); tip = m_chain.Tip(); LogPrintf("Loaded best chain: hashBestChain=%s height=%d date=%s progress=%f\n", tip->GetBlockHash().ToString(), m_chain.Height(), FormatISO8601DateTime(tip->GetBlockTime()), GuessVerificationProgress(m_params.TxData(), tip)); return true; } CVerifyDB::CVerifyDB() { uiInterface.ShowProgress(_("Verifying blocks…").translated, 0, false); } CVerifyDB::~CVerifyDB() { uiInterface.ShowProgress("", 100, false); } bool CVerifyDB::VerifyDB( Chainstate& chainstate, const Consensus::Params& consensus_params, CCoinsView& coinsview, int nCheckLevel, int nCheckDepth) { AssertLockHeld(cs_main); if (chainstate.m_chain.Tip() == nullptr || chainstate.m_chain.Tip()->pprev == nullptr) { return true; } // Verify blocks in the best chain if (nCheckDepth <= 0 || nCheckDepth > chainstate.m_chain.Height()) { nCheckDepth = chainstate.m_chain.Height(); } nCheckLevel = std::max(0, std::min(4, nCheckLevel)); LogPrintf("Verifying last %i blocks at level %i\n", nCheckDepth, nCheckLevel); CCoinsViewCache coins(&coinsview); CBlockIndex* pindex; CBlockIndex* pindexFailure = nullptr; int nGoodTransactions = 0; BlockValidationState state; int reportDone = 0; LogPrintf("[0%%]..."); /* Continued */ const bool is_snapshot_cs{!chainstate.m_from_snapshot_blockhash}; for (pindex = chainstate.m_chain.Tip(); pindex && pindex->pprev; pindex = pindex->pprev) { const int percentageDone = std::max(1, std::min(99, (int)(((double)(chainstate.m_chain.Height() - pindex->nHeight)) / (double)nCheckDepth * (nCheckLevel >= 4 ? 50 : 100)))); if (reportDone < percentageDone / 10) { // report every 10% step LogPrintf("[%d%%]...", percentageDone); /* Continued */ reportDone = percentageDone / 10; } uiInterface.ShowProgress(_("Verifying blocks…").translated, percentageDone, false); if (pindex->nHeight <= chainstate.m_chain.Height() - nCheckDepth) { break; } if ((fPruneMode || is_snapshot_cs) && !(pindex->nStatus & BLOCK_HAVE_DATA)) { // If pruning or running under an assumeutxo snapshot, only go // back as far as we have data. LogPrintf("VerifyDB(): block verification stopping at height %d (pruning, no data)\n", pindex->nHeight); break; } CBlock block; // check level 0: read from disk if (!ReadBlockFromDisk(block, pindex, consensus_params)) { return error("VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString()); } // check level 1: verify block validity if (nCheckLevel >= 1 && !CheckBlock(block, state, consensus_params)) { return error("%s: *** found bad block at %d, hash=%s (%s)\n", __func__, pindex->nHeight, pindex->GetBlockHash().ToString(), state.ToString()); } // check level 2: verify undo validity if (nCheckLevel >= 2 && pindex) { CBlockUndo undo; if (!pindex->GetUndoPos().IsNull()) { if (!UndoReadFromDisk(undo, pindex)) { return error("VerifyDB(): *** found bad undo data at %d, hash=%s\n", pindex->nHeight, pindex->GetBlockHash().ToString()); } } } // check level 3: check for inconsistencies during memory-only disconnect of tip blocks size_t curr_coins_usage = coins.DynamicMemoryUsage() + chainstate.CoinsTip().DynamicMemoryUsage(); if (nCheckLevel >= 3 && curr_coins_usage <= chainstate.m_coinstip_cache_size_bytes) { assert(coins.GetBestBlock() == pindex->GetBlockHash()); DisconnectResult res = chainstate.DisconnectBlock(block, pindex, coins); if (res == DISCONNECT_FAILED) { return error("VerifyDB(): *** irrecoverable inconsistency in block data at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString()); } if (res == DISCONNECT_UNCLEAN) { nGoodTransactions = 0; pindexFailure = pindex; } else { nGoodTransactions += block.vtx.size(); } } if (ShutdownRequested()) return true; } if (pindexFailure) { return error("VerifyDB(): *** coin database inconsistencies found (last %i blocks, %i good transactions before that)\n", chainstate.m_chain.Height() - pindexFailure->nHeight + 1, nGoodTransactions); } // store block count as we move pindex at check level >= 4 int block_count = chainstate.m_chain.Height() - pindex->nHeight; // check level 4: try reconnecting blocks if (nCheckLevel >= 4) { while (pindex != chainstate.m_chain.Tip()) { const int percentageDone = std::max(1, std::min(99, 100 - (int)(((double)(chainstate.m_chain.Height() - pindex->nHeight)) / (double)nCheckDepth * 50))); if (reportDone < percentageDone / 10) { // report every 10% step LogPrintf("[%d%%]...", percentageDone); /* Continued */ reportDone = percentageDone / 10; } uiInterface.ShowProgress(_("Verifying blocks…").translated, percentageDone, false); pindex = chainstate.m_chain.Next(pindex); CBlock block; if (!ReadBlockFromDisk(block, pindex, consensus_params)) return error("VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString()); if (!chainstate.ConnectBlock(block, state, pindex, coins)) { return error("VerifyDB(): *** found unconnectable block at %d, hash=%s (%s)", pindex->nHeight, pindex->GetBlockHash().ToString(), state.ToString()); } if (ShutdownRequested()) return true; } } LogPrintf("[DONE].\n"); LogPrintf("No coin database inconsistencies in last %i blocks (%i transactions)\n", block_count, nGoodTransactions); return true; } /** Apply the effects of a block on the utxo cache, ignoring that it may already have been applied. */ bool Chainstate::RollforwardBlock(const CBlockIndex* pindex, CCoinsViewCache& inputs) { AssertLockHeld(cs_main); // TODO: merge with ConnectBlock CBlock block; if (!ReadBlockFromDisk(block, pindex, m_params.GetConsensus())) { return error("ReplayBlock(): ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString()); } for (const CTransactionRef& tx : block.vtx) { if (!tx->IsCoinBase()) { for (const CTxIn &txin : tx->vin) { inputs.SpendCoin(txin.prevout); } } // Pass check = true as every addition may be an overwrite. AddCoins(inputs, *tx, pindex->nHeight, true); } return true; } bool Chainstate::ReplayBlocks() { LOCK(cs_main); CCoinsView& db = this->CoinsDB(); CCoinsViewCache cache(&db); std::vector<uint256> hashHeads = db.GetHeadBlocks(); if (hashHeads.empty()) return true; // We're already in a consistent state. if (hashHeads.size() != 2) return error("ReplayBlocks(): unknown inconsistent state"); uiInterface.ShowProgress(_("Replaying blocks…").translated, 0, false); LogPrintf("Replaying blocks\n"); const CBlockIndex* pindexOld = nullptr; // Old tip during the interrupted flush. const CBlockIndex* pindexNew; // New tip during the interrupted flush. const CBlockIndex* pindexFork = nullptr; // Latest block common to both the old and the new tip. if (m_blockman.m_block_index.count(hashHeads[0]) == 0) { return error("ReplayBlocks(): reorganization to unknown block requested"); } pindexNew = &(m_blockman.m_block_index[hashHeads[0]]); if (!hashHeads[1].IsNull()) { // The old tip is allowed to be 0, indicating it's the first flush. if (m_blockman.m_block_index.count(hashHeads[1]) == 0) { return error("ReplayBlocks(): reorganization from unknown block requested"); } pindexOld = &(m_blockman.m_block_index[hashHeads[1]]); pindexFork = LastCommonAncestor(pindexOld, pindexNew); assert(pindexFork != nullptr); } // Rollback along the old branch. while (pindexOld != pindexFork) { if (pindexOld->nHeight > 0) { // Never disconnect the genesis block. CBlock block; if (!ReadBlockFromDisk(block, pindexOld, m_params.GetConsensus())) { return error("RollbackBlock(): ReadBlockFromDisk() failed at %d, hash=%s", pindexOld->nHeight, pindexOld->GetBlockHash().ToString()); } LogPrintf("Rolling back %s (%i)\n", pindexOld->GetBlockHash().ToString(), pindexOld->nHeight); DisconnectResult res = DisconnectBlock(block, pindexOld, cache); if (res == DISCONNECT_FAILED) { return error("RollbackBlock(): DisconnectBlock failed at %d, hash=%s", pindexOld->nHeight, pindexOld->GetBlockHash().ToString()); } // If DISCONNECT_UNCLEAN is returned, it means a non-existing UTXO was deleted, or an existing UTXO was // overwritten. It corresponds to cases where the block-to-be-disconnect never had all its operations // applied to the UTXO set. However, as both writing a UTXO and deleting a UTXO are idempotent operations, // the result is still a version of the UTXO set with the effects of that block undone. } pindexOld = pindexOld->pprev; } // Roll forward from the forking point to the new tip. int nForkHeight = pindexFork ? pindexFork->nHeight : 0; for (int nHeight = nForkHeight + 1; nHeight <= pindexNew->nHeight; ++nHeight) { const CBlockIndex& pindex{*Assert(pindexNew->GetAncestor(nHeight))}; LogPrintf("Rolling forward %s (%i)\n", pindex.GetBlockHash().ToString(), nHeight); uiInterface.ShowProgress(_("Replaying blocks…").translated, (int) ((nHeight - nForkHeight) * 100.0 / (pindexNew->nHeight - nForkHeight)) , false); if (!RollforwardBlock(&pindex, cache)) return false; } cache.SetBestBlock(pindexNew->GetBlockHash()); cache.Flush(); uiInterface.ShowProgress("", 100, false); return true; } bool Chainstate::NeedsRedownload() const { AssertLockHeld(cs_main); // At and above m_params.SegwitHeight, segwit consensus rules must be validated CBlockIndex* block{m_chain.Tip()}; while (block != nullptr && DeploymentActiveAt(*block, m_chainman, Consensus::DEPLOYMENT_SEGWIT)) { if (!(block->nStatus & BLOCK_OPT_WITNESS)) { // block is insufficiently validated for a segwit client return true; } block = block->pprev; } return false; } void Chainstate::UnloadBlockIndex() { AssertLockHeld(::cs_main); nBlockSequenceId = 1; setBlockIndexCandidates.clear(); } bool ChainstateManager::LoadBlockIndex() { AssertLockHeld(cs_main); // Load block index from databases bool needs_init = fReindex; if (!fReindex) { bool ret = m_blockman.LoadBlockIndexDB(GetConsensus()); if (!ret) return false; std::vector<CBlockIndex*> vSortedByHeight{m_blockman.GetAllBlockIndices()}; std::sort(vSortedByHeight.begin(), vSortedByHeight.end(), CBlockIndexHeightOnlyComparator()); // Find start of assumed-valid region. int first_assumed_valid_height = std::numeric_limits<int>::max(); for (const CBlockIndex* block : vSortedByHeight) { if (block->IsAssumedValid()) { auto chainstates = GetAll(); // If we encounter an assumed-valid block index entry, ensure that we have // one chainstate that tolerates assumed-valid entries and another that does // not (i.e. the background validation chainstate), since assumed-valid // entries should always be pending validation by a fully-validated chainstate. auto any_chain = [&](auto fnc) { return std::any_of(chainstates.cbegin(), chainstates.cend(), fnc); }; assert(any_chain([](auto chainstate) { return chainstate->reliesOnAssumedValid(); })); assert(any_chain([](auto chainstate) { return !chainstate->reliesOnAssumedValid(); })); first_assumed_valid_height = block->nHeight; break; } } for (CBlockIndex* pindex : vSortedByHeight) { if (ShutdownRequested()) return false; if (pindex->IsAssumedValid() || (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && (pindex->HaveTxsDownloaded() || pindex->pprev == nullptr))) { // Fill each chainstate's block candidate set. Only add assumed-valid // blocks to the tip candidate set if the chainstate is allowed to rely on // assumed-valid blocks. // // If all setBlockIndexCandidates contained the assumed-valid blocks, the // background chainstate's ActivateBestChain() call would add assumed-valid // blocks to the chain (based on how FindMostWorkChain() works). Obviously // we don't want this since the purpose of the background validation chain // is to validate assued-valid blocks. // // Note: This is considering all blocks whose height is greater or equal to // the first assumed-valid block to be assumed-valid blocks, and excluding // them from the background chainstate's setBlockIndexCandidates set. This // does mean that some blocks which are not technically assumed-valid // (later blocks on a fork beginning before the first assumed-valid block) // might not get added to the background chainstate, but this is ok, // because they will still be attached to the active chainstate if they // actually contain more work. // // Instead of this height-based approach, an earlier attempt was made at // detecting "holistically" whether the block index under consideration // relied on an assumed-valid ancestor, but this proved to be too slow to // be practical. for (Chainstate* chainstate : GetAll()) { if (chainstate->reliesOnAssumedValid() || pindex->nHeight < first_assumed_valid_height) { chainstate->setBlockIndexCandidates.insert(pindex); } } } if (pindex->nStatus & BLOCK_FAILED_MASK && (!m_best_invalid || pindex->nChainWork > m_best_invalid->nChainWork)) { m_best_invalid = pindex; } if (pindex->IsValid(BLOCK_VALID_TREE) && (m_best_header == nullptr || CBlockIndexWorkComparator()(m_best_header, pindex))) m_best_header = pindex; } needs_init = m_blockman.m_block_index.empty(); } if (needs_init) { // Everything here is for *new* reindex/DBs. Thus, though // LoadBlockIndexDB may have set fReindex if we shut down // mid-reindex previously, we don't check fReindex and // instead only check it prior to LoadBlockIndexDB to set // needs_init. LogPrintf("Initializing databases...\n"); } return true; } bool Chainstate::LoadGenesisBlock() { LOCK(cs_main); // Check whether we're already initialized by checking for genesis in // m_blockman.m_block_index. Note that we can't use m_chain here, since it is // set based on the coins db, not the block index db, which is the only // thing loaded at this point. if (m_blockman.m_block_index.count(m_params.GenesisBlock().GetHash())) return true; try { const CBlock& block = m_params.GenesisBlock(); FlatFilePos blockPos{m_blockman.SaveBlockToDisk(block, 0, m_chain, m_params, nullptr)}; if (blockPos.IsNull()) { return error("%s: writing genesis block to disk failed", __func__); } CBlockIndex* pindex = m_blockman.AddToBlockIndex(block, m_chainman.m_best_header); ReceivedBlockTransactions(block, pindex, blockPos); } catch (const std::runtime_error& e) { return error("%s: failed to write genesis block: %s", __func__, e.what()); } return true; } void Chainstate::LoadExternalBlockFile( FILE* fileIn, FlatFilePos* dbp, std::multimap<uint256, FlatFilePos>* blocks_with_unknown_parent) { AssertLockNotHeld(m_chainstate_mutex); // Either both should be specified (-reindex), or neither (-loadblock). assert(!dbp == !blocks_with_unknown_parent); const auto start{SteadyClock::now()}; int nLoaded = 0; try { // This takes over fileIn and calls fclose() on it in the CBufferedFile destructor CBufferedFile blkdat(fileIn, 2*MAX_BLOCK_SERIALIZED_SIZE, MAX_BLOCK_SERIALIZED_SIZE+8, SER_DISK, CLIENT_VERSION); uint64_t nRewind = blkdat.GetPos(); while (!blkdat.eof()) { if (ShutdownRequested()) return; blkdat.SetPos(nRewind); nRewind++; // start one byte further next time, in case of failure blkdat.SetLimit(); // remove former limit unsigned int nSize = 0; try { // locate a header unsigned char buf[CMessageHeader::MESSAGE_START_SIZE]; blkdat.FindByte(m_params.MessageStart()[0]); nRewind = blkdat.GetPos() + 1; blkdat >> buf; if (memcmp(buf, m_params.MessageStart(), CMessageHeader::MESSAGE_START_SIZE)) { continue; } // read size blkdat >> nSize; if (nSize < 80 || nSize > MAX_BLOCK_SERIALIZED_SIZE) continue; } catch (const std::exception&) { // no valid block header found; don't complain break; } try { // read block uint64_t nBlockPos = blkdat.GetPos(); if (dbp) dbp->nPos = nBlockPos; blkdat.SetLimit(nBlockPos + nSize); std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>(); CBlock& block = *pblock; blkdat >> block; nRewind = blkdat.GetPos(); uint256 hash = block.GetHash(); { LOCK(cs_main); // detect out of order blocks, and store them for later if (hash != m_params.GetConsensus().hashGenesisBlock && !m_blockman.LookupBlockIndex(block.hashPrevBlock)) { LogPrint(BCLog::REINDEX, "%s: Out of order block %s, parent %s not known\n", __func__, hash.ToString(), block.hashPrevBlock.ToString()); if (dbp && blocks_with_unknown_parent) { blocks_with_unknown_parent->emplace(block.hashPrevBlock, *dbp); } continue; } // process in case the block isn't known yet const CBlockIndex* pindex = m_blockman.LookupBlockIndex(hash); if (!pindex || (pindex->nStatus & BLOCK_HAVE_DATA) == 0) { BlockValidationState state; if (AcceptBlock(pblock, state, nullptr, true, dbp, nullptr, true)) { nLoaded++; } if (state.IsError()) { break; } } else if (hash != m_params.GetConsensus().hashGenesisBlock && pindex->nHeight % 1000 == 0) { LogPrint(BCLog::REINDEX, "Block Import: already had block %s at height %d\n", hash.ToString(), pindex->nHeight); } } // Activate the genesis block so normal node progress can continue if (hash == m_params.GetConsensus().hashGenesisBlock) { BlockValidationState state; if (!ActivateBestChain(state, nullptr)) { break; } } NotifyHeaderTip(*this); if (!blocks_with_unknown_parent) continue; // Recursively process earlier encountered successors of this block std::deque<uint256> queue; queue.push_back(hash); while (!queue.empty()) { uint256 head = queue.front(); queue.pop_front(); auto range = blocks_with_unknown_parent->equal_range(head); while (range.first != range.second) { std::multimap<uint256, FlatFilePos>::iterator it = range.first; std::shared_ptr<CBlock> pblockrecursive = std::make_shared<CBlock>(); if (ReadBlockFromDisk(*pblockrecursive, it->second, m_params.GetConsensus())) { LogPrint(BCLog::REINDEX, "%s: Processing out of order child %s of %s\n", __func__, pblockrecursive->GetHash().ToString(), head.ToString()); LOCK(cs_main); BlockValidationState dummy; if (AcceptBlock(pblockrecursive, dummy, nullptr, true, &it->second, nullptr, true)) { nLoaded++; queue.push_back(pblockrecursive->GetHash()); } } range.first++; blocks_with_unknown_parent->erase(it); NotifyHeaderTip(*this); } } } catch (const std::exception& e) { LogPrintf("%s: Deserialize or I/O error - %s\n", __func__, e.what()); } } } catch (const std::runtime_error& e) { AbortNode(std::string("System error: ") + e.what()); } LogPrintf("Loaded %i blocks from external file in %dms\n", nLoaded, Ticks<std::chrono::milliseconds>(SteadyClock::now() - start)); } void Chainstate::CheckBlockIndex() { if (!fCheckBlockIndex) { return; } LOCK(cs_main); // During a reindex, we read the genesis block and call CheckBlockIndex before ActivateBestChain, // so we have the genesis block in m_blockman.m_block_index but no active chain. (A few of the // tests when iterating the block tree require that m_chain has been initialized.) if (m_chain.Height() < 0) { assert(m_blockman.m_block_index.size() <= 1); return; } // Build forward-pointing map of the entire block tree. std::multimap<CBlockIndex*,CBlockIndex*> forward; for (auto& [_, block_index] : m_blockman.m_block_index) { forward.emplace(block_index.pprev, &block_index); } assert(forward.size() == m_blockman.m_block_index.size()); std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangeGenesis = forward.equal_range(nullptr); CBlockIndex *pindex = rangeGenesis.first->second; rangeGenesis.first++; assert(rangeGenesis.first == rangeGenesis.second); // There is only one index entry with parent nullptr. // Iterate over the entire block tree, using depth-first search. // Along the way, remember whether there are blocks on the path from genesis // block being explored which are the first to have certain properties. size_t nNodes = 0; int nHeight = 0; CBlockIndex* pindexFirstInvalid = nullptr; // Oldest ancestor of pindex which is invalid. CBlockIndex* pindexFirstMissing = nullptr; // Oldest ancestor of pindex which does not have BLOCK_HAVE_DATA. CBlockIndex* pindexFirstNeverProcessed = nullptr; // Oldest ancestor of pindex for which nTx == 0. CBlockIndex* pindexFirstNotTreeValid = nullptr; // Oldest ancestor of pindex which does not have BLOCK_VALID_TREE (regardless of being valid or not). CBlockIndex* pindexFirstNotTransactionsValid = nullptr; // Oldest ancestor of pindex which does not have BLOCK_VALID_TRANSACTIONS (regardless of being valid or not). CBlockIndex* pindexFirstNotChainValid = nullptr; // Oldest ancestor of pindex which does not have BLOCK_VALID_CHAIN (regardless of being valid or not). CBlockIndex* pindexFirstNotScriptsValid = nullptr; // Oldest ancestor of pindex which does not have BLOCK_VALID_SCRIPTS (regardless of being valid or not). while (pindex != nullptr) { nNodes++; if (pindexFirstInvalid == nullptr && pindex->nStatus & BLOCK_FAILED_VALID) pindexFirstInvalid = pindex; // Assumed-valid index entries will not have data since we haven't downloaded the // full block yet. if (pindexFirstMissing == nullptr && !(pindex->nStatus & BLOCK_HAVE_DATA) && !pindex->IsAssumedValid()) { pindexFirstMissing = pindex; } if (pindexFirstNeverProcessed == nullptr && pindex->nTx == 0) pindexFirstNeverProcessed = pindex; if (pindex->pprev != nullptr && pindexFirstNotTreeValid == nullptr && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TREE) pindexFirstNotTreeValid = pindex; if (pindex->pprev != nullptr && !pindex->IsAssumedValid()) { // Skip validity flag checks for BLOCK_ASSUMED_VALID index entries, since these // *_VALID_MASK flags will not be present for index entries we are temporarily assuming // valid. if (pindexFirstNotTransactionsValid == nullptr && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TRANSACTIONS) { pindexFirstNotTransactionsValid = pindex; } if (pindexFirstNotChainValid == nullptr && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_CHAIN) { pindexFirstNotChainValid = pindex; } if (pindexFirstNotScriptsValid == nullptr && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_SCRIPTS) { pindexFirstNotScriptsValid = pindex; } } // Begin: actual consistency checks. if (pindex->pprev == nullptr) { // Genesis block checks. assert(pindex->GetBlockHash() == m_params.GetConsensus().hashGenesisBlock); // Genesis block's hash must match. assert(pindex == m_chain.Genesis()); // The current active chain's genesis block must be this block. } if (!pindex->HaveTxsDownloaded()) assert(pindex->nSequenceId <= 0); // nSequenceId can't be set positive for blocks that aren't linked (negative is used for preciousblock) // VALID_TRANSACTIONS is equivalent to nTx > 0 for all nodes (whether or not pruning has occurred). // HAVE_DATA is only equivalent to nTx > 0 (or VALID_TRANSACTIONS) if no pruning has occurred. // Unless these indexes are assumed valid and pending block download on a // background chainstate. if (!m_blockman.m_have_pruned && !pindex->IsAssumedValid()) { // If we've never pruned, then HAVE_DATA should be equivalent to nTx > 0 assert(!(pindex->nStatus & BLOCK_HAVE_DATA) == (pindex->nTx == 0)); assert(pindexFirstMissing == pindexFirstNeverProcessed); } else { // If we have pruned, then we can only say that HAVE_DATA implies nTx > 0 if (pindex->nStatus & BLOCK_HAVE_DATA) assert(pindex->nTx > 0); } if (pindex->nStatus & BLOCK_HAVE_UNDO) assert(pindex->nStatus & BLOCK_HAVE_DATA); if (pindex->IsAssumedValid()) { // Assumed-valid blocks should have some nTx value. assert(pindex->nTx > 0); // Assumed-valid blocks should connect to the main chain. assert((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TREE); } else { // Otherwise there should only be an nTx value if we have // actually seen a block's transactions. assert(((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TRANSACTIONS) == (pindex->nTx > 0)); // This is pruning-independent. } // All parents having had data (at some point) is equivalent to all parents being VALID_TRANSACTIONS, which is equivalent to HaveTxsDownloaded(). assert((pindexFirstNeverProcessed == nullptr) == pindex->HaveTxsDownloaded()); assert((pindexFirstNotTransactionsValid == nullptr) == pindex->HaveTxsDownloaded()); assert(pindex->nHeight == nHeight); // nHeight must be consistent. assert(pindex->pprev == nullptr || pindex->nChainWork >= pindex->pprev->nChainWork); // For every block except the genesis block, the chainwork must be larger than the parent's. assert(nHeight < 2 || (pindex->pskip && (pindex->pskip->nHeight < nHeight))); // The pskip pointer must point back for all but the first 2 blocks. assert(pindexFirstNotTreeValid == nullptr); // All m_blockman.m_block_index entries must at least be TREE valid if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TREE) assert(pindexFirstNotTreeValid == nullptr); // TREE valid implies all parents are TREE valid if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_CHAIN) assert(pindexFirstNotChainValid == nullptr); // CHAIN valid implies all parents are CHAIN valid if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_SCRIPTS) assert(pindexFirstNotScriptsValid == nullptr); // SCRIPTS valid implies all parents are SCRIPTS valid if (pindexFirstInvalid == nullptr) { // Checks for not-invalid blocks. assert((pindex->nStatus & BLOCK_FAILED_MASK) == 0); // The failed mask cannot be set for blocks without invalid parents. } if (!CBlockIndexWorkComparator()(pindex, m_chain.Tip()) && pindexFirstNeverProcessed == nullptr) { if (pindexFirstInvalid == nullptr) { const bool is_active = this == &m_chainman.ActiveChainstate(); // If this block sorts at least as good as the current tip and // is valid and we have all data for its parents, it must be in // setBlockIndexCandidates. m_chain.Tip() must also be there // even if some data has been pruned. // // Don't perform this check for the background chainstate since // its setBlockIndexCandidates shouldn't have some entries (i.e. those past the // snapshot block) which do exist in the block index for the active chainstate. if (is_active && (pindexFirstMissing == nullptr || pindex == m_chain.Tip())) { assert(setBlockIndexCandidates.count(pindex)); } // If some parent is missing, then it could be that this block was in // setBlockIndexCandidates but had to be removed because of the missing data. // In this case it must be in m_blocks_unlinked -- see test below. } } else { // If this block sorts worse than the current tip or some ancestor's block has never been seen, it cannot be in setBlockIndexCandidates. assert(setBlockIndexCandidates.count(pindex) == 0); } // Check whether this block is in m_blocks_unlinked. std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangeUnlinked = m_blockman.m_blocks_unlinked.equal_range(pindex->pprev); bool foundInUnlinked = false; while (rangeUnlinked.first != rangeUnlinked.second) { assert(rangeUnlinked.first->first == pindex->pprev); if (rangeUnlinked.first->second == pindex) { foundInUnlinked = true; break; } rangeUnlinked.first++; } if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed != nullptr && pindexFirstInvalid == nullptr) { // If this block has block data available, some parent was never received, and has no invalid parents, it must be in m_blocks_unlinked. assert(foundInUnlinked); } if (!(pindex->nStatus & BLOCK_HAVE_DATA)) assert(!foundInUnlinked); // Can't be in m_blocks_unlinked if we don't HAVE_DATA if (pindexFirstMissing == nullptr) assert(!foundInUnlinked); // We aren't missing data for any parent -- cannot be in m_blocks_unlinked. if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed == nullptr && pindexFirstMissing != nullptr) { // We HAVE_DATA for this block, have received data for all parents at some point, but we're currently missing data for some parent. assert(m_blockman.m_have_pruned); // We must have pruned. // This block may have entered m_blocks_unlinked if: // - it has a descendant that at some point had more work than the // tip, and // - we tried switching to that descendant but were missing // data for some intermediate block between m_chain and the // tip. // So if this block is itself better than m_chain.Tip() and it wasn't in // setBlockIndexCandidates, then it must be in m_blocks_unlinked. if (!CBlockIndexWorkComparator()(pindex, m_chain.Tip()) && setBlockIndexCandidates.count(pindex) == 0) { if (pindexFirstInvalid == nullptr) { assert(foundInUnlinked); } } } // assert(pindex->GetBlockHash() == pindex->GetBlockHeader().GetHash()); // Perhaps too slow // End: actual consistency checks. // Try descending into the first subnode. std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> range = forward.equal_range(pindex); if (range.first != range.second) { // A subnode was found. pindex = range.first->second; nHeight++; continue; } // This is a leaf node. // Move upwards until we reach a node of which we have not yet visited the last child. while (pindex) { // We are going to either move to a parent or a sibling of pindex. // If pindex was the first with a certain property, unset the corresponding variable. if (pindex == pindexFirstInvalid) pindexFirstInvalid = nullptr; if (pindex == pindexFirstMissing) pindexFirstMissing = nullptr; if (pindex == pindexFirstNeverProcessed) pindexFirstNeverProcessed = nullptr; if (pindex == pindexFirstNotTreeValid) pindexFirstNotTreeValid = nullptr; if (pindex == pindexFirstNotTransactionsValid) pindexFirstNotTransactionsValid = nullptr; if (pindex == pindexFirstNotChainValid) pindexFirstNotChainValid = nullptr; if (pindex == pindexFirstNotScriptsValid) pindexFirstNotScriptsValid = nullptr; // Find our parent. CBlockIndex* pindexPar = pindex->pprev; // Find which child we just visited. std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangePar = forward.equal_range(pindexPar); while (rangePar.first->second != pindex) { assert(rangePar.first != rangePar.second); // Our parent must have at least the node we're coming from as child. rangePar.first++; } // Proceed to the next one. rangePar.first++; if (rangePar.first != rangePar.second) { // Move to the sibling. pindex = rangePar.first->second; break; } else { // Move up further. pindex = pindexPar; nHeight--; continue; } } } // Check that we actually traversed the entire map. assert(nNodes == forward.size()); } std::string Chainstate::ToString() { AssertLockHeld(::cs_main); CBlockIndex* tip = m_chain.Tip(); return strprintf("Chainstate [%s] @ height %d (%s)", m_from_snapshot_blockhash ? "snapshot" : "ibd", tip ? tip->nHeight : -1, tip ? tip->GetBlockHash().ToString() : "null"); } bool Chainstate::ResizeCoinsCaches(size_t coinstip_size, size_t coinsdb_size) { AssertLockHeld(::cs_main); if (coinstip_size == m_coinstip_cache_size_bytes && coinsdb_size == m_coinsdb_cache_size_bytes) { // Cache sizes are unchanged, no need to continue. return true; } size_t old_coinstip_size = m_coinstip_cache_size_bytes; m_coinstip_cache_size_bytes = coinstip_size; m_coinsdb_cache_size_bytes = coinsdb_size; CoinsDB().ResizeCache(coinsdb_size); LogPrintf("[%s] resized coinsdb cache to %.1f MiB\n", this->ToString(), coinsdb_size * (1.0 / 1024 / 1024)); LogPrintf("[%s] resized coinstip cache to %.1f MiB\n", this->ToString(), coinstip_size * (1.0 / 1024 / 1024)); BlockValidationState state; bool ret; if (coinstip_size > old_coinstip_size) { // Likely no need to flush if cache sizes have grown. ret = FlushStateToDisk(state, FlushStateMode::IF_NEEDED); } else { // Otherwise, flush state to disk and deallocate the in-memory coins map. ret = FlushStateToDisk(state, FlushStateMode::ALWAYS); CoinsTip().ReallocateCache(); } return ret; } //! Guess how far we are in the verification process at the given block index //! require cs_main if pindex has not been validated yet (because nChainTx might be unset) double GuessVerificationProgress(const ChainTxData& data, const CBlockIndex *pindex) { if (pindex == nullptr) return 0.0; int64_t nNow = time(nullptr); double fTxTotal; if (pindex->nChainTx <= data.nTxCount) { fTxTotal = data.nTxCount + (nNow - data.nTime) * data.dTxRate; } else { fTxTotal = pindex->nChainTx + (nNow - pindex->GetBlockTime()) * data.dTxRate; } return std::min<double>(pindex->nChainTx / fTxTotal, 1.0); } std::optional<uint256> ChainstateManager::SnapshotBlockhash() const { LOCK(::cs_main); if (m_active_chainstate && m_active_chainstate->m_from_snapshot_blockhash) { // If a snapshot chainstate exists, it will always be our active. return m_active_chainstate->m_from_snapshot_blockhash; } return std::nullopt; } std::vector<Chainstate*> ChainstateManager::GetAll() { LOCK(::cs_main); std::vector<Chainstate*> out; if (!IsSnapshotValidated() && m_ibd_chainstate) { out.push_back(m_ibd_chainstate.get()); } if (m_snapshot_chainstate) { out.push_back(m_snapshot_chainstate.get()); } return out; } Chainstate& ChainstateManager::InitializeChainstate( CTxMemPool* mempool, const std::optional<uint256>& snapshot_blockhash) { AssertLockHeld(::cs_main); bool is_snapshot = snapshot_blockhash.has_value(); std::unique_ptr<Chainstate>& to_modify = is_snapshot ? m_snapshot_chainstate : m_ibd_chainstate; if (to_modify) { throw std::logic_error("should not be overwriting a chainstate"); } to_modify.reset(new Chainstate(mempool, m_blockman, *this, snapshot_blockhash)); // Snapshot chainstates and initial IBD chaintates always become active. if (is_snapshot || (!is_snapshot && !m_active_chainstate)) { LogPrintf("Switching active chainstate to %s\n", to_modify->ToString()); m_active_chainstate = to_modify.get(); } else { throw std::logic_error("unexpected chainstate activation"); } return *to_modify; } const AssumeutxoData* ExpectedAssumeutxo( const int height, const CChainParams& chainparams) { const MapAssumeutxo& valid_assumeutxos_map = chainparams.Assumeutxo(); const auto assumeutxo_found = valid_assumeutxos_map.find(height); if (assumeutxo_found != valid_assumeutxos_map.end()) { return &assumeutxo_found->second; } return nullptr; } bool ChainstateManager::ActivateSnapshot( AutoFile& coins_file, const SnapshotMetadata& metadata, bool in_memory) { uint256 base_blockhash = metadata.m_base_blockhash; if (this->SnapshotBlockhash()) { LogPrintf("[snapshot] can't activate a snapshot-based chainstate more than once\n"); return false; } int64_t current_coinsdb_cache_size{0}; int64_t current_coinstip_cache_size{0}; // Cache percentages to allocate to each chainstate. // // These particular percentages don't matter so much since they will only be // relevant during snapshot activation; caches are rebalanced at the conclusion of // this function. We want to give (essentially) all available cache capacity to the // snapshot to aid the bulk load later in this function. static constexpr double IBD_CACHE_PERC = 0.01; static constexpr double SNAPSHOT_CACHE_PERC = 0.99; { LOCK(::cs_main); // Resize the coins caches to ensure we're not exceeding memory limits. // // Allocate the majority of the cache to the incoming snapshot chainstate, since // (optimistically) getting to its tip will be the top priority. We'll need to call // `MaybeRebalanceCaches()` once we're done with this function to ensure // the right allocation (including the possibility that no snapshot was activated // and that we should restore the active chainstate caches to their original size). // current_coinsdb_cache_size = this->ActiveChainstate().m_coinsdb_cache_size_bytes; current_coinstip_cache_size = this->ActiveChainstate().m_coinstip_cache_size_bytes; // Temporarily resize the active coins cache to make room for the newly-created // snapshot chain. this->ActiveChainstate().ResizeCoinsCaches( static_cast<size_t>(current_coinstip_cache_size * IBD_CACHE_PERC), static_cast<size_t>(current_coinsdb_cache_size * IBD_CACHE_PERC)); } auto snapshot_chainstate = WITH_LOCK(::cs_main, return std::make_unique<Chainstate>( /*mempool=*/nullptr, m_blockman, *this, base_blockhash)); { LOCK(::cs_main); snapshot_chainstate->InitCoinsDB( static_cast<size_t>(current_coinsdb_cache_size * SNAPSHOT_CACHE_PERC), in_memory, false, "chainstate"); snapshot_chainstate->InitCoinsCache( static_cast<size_t>(current_coinstip_cache_size * SNAPSHOT_CACHE_PERC)); } const bool snapshot_ok = this->PopulateAndValidateSnapshot( *snapshot_chainstate, coins_file, metadata); if (!snapshot_ok) { WITH_LOCK(::cs_main, this->MaybeRebalanceCaches()); return false; } { LOCK(::cs_main); assert(!m_snapshot_chainstate); m_snapshot_chainstate.swap(snapshot_chainstate); const bool chaintip_loaded = m_snapshot_chainstate->LoadChainTip(); assert(chaintip_loaded); m_active_chainstate = m_snapshot_chainstate.get(); LogPrintf("[snapshot] successfully activated snapshot %s\n", base_blockhash.ToString()); LogPrintf("[snapshot] (%.2f MB)\n", m_snapshot_chainstate->CoinsTip().DynamicMemoryUsage() / (1000 * 1000)); this->MaybeRebalanceCaches(); } return true; } static void FlushSnapshotToDisk(CCoinsViewCache& coins_cache, bool snapshot_loaded) { LOG_TIME_MILLIS_WITH_CATEGORY_MSG_ONCE( strprintf("%s (%.2f MB)", snapshot_loaded ? "saving snapshot chainstate" : "flushing coins cache", coins_cache.DynamicMemoryUsage() / (1000 * 1000)), BCLog::LogFlags::ALL); coins_cache.Flush(); } bool ChainstateManager::PopulateAndValidateSnapshot( Chainstate& snapshot_chainstate, AutoFile& coins_file, const SnapshotMetadata& metadata) { // It's okay to release cs_main before we're done using `coins_cache` because we know // that nothing else will be referencing the newly created snapshot_chainstate yet. CCoinsViewCache& coins_cache = *WITH_LOCK(::cs_main, return &snapshot_chainstate.CoinsTip()); uint256 base_blockhash = metadata.m_base_blockhash; CBlockIndex* snapshot_start_block = WITH_LOCK(::cs_main, return m_blockman.LookupBlockIndex(base_blockhash)); if (!snapshot_start_block) { // Needed for ComputeUTXOStats and ExpectedAssumeutxo to determine the // height and to avoid a crash when base_blockhash.IsNull() LogPrintf("[snapshot] Did not find snapshot start blockheader %s\n", base_blockhash.ToString()); return false; } int base_height = snapshot_start_block->nHeight; auto maybe_au_data = ExpectedAssumeutxo(base_height, GetParams()); if (!maybe_au_data) { LogPrintf("[snapshot] assumeutxo height in snapshot metadata not recognized " /* Continued */ "(%d) - refusing to load snapshot\n", base_height); return false; } const AssumeutxoData& au_data = *maybe_au_data; COutPoint outpoint; Coin coin; const uint64_t coins_count = metadata.m_coins_count; uint64_t coins_left = metadata.m_coins_count; LogPrintf("[snapshot] loading coins from snapshot %s\n", base_blockhash.ToString()); int64_t coins_processed{0}; while (coins_left > 0) { try { coins_file >> outpoint; coins_file >> coin; } catch (const std::ios_base::failure&) { LogPrintf("[snapshot] bad snapshot format or truncated snapshot after deserializing %d coins\n", coins_count - coins_left); return false; } if (coin.nHeight > base_height || outpoint.n >= std::numeric_limits<decltype(outpoint.n)>::max() // Avoid integer wrap-around in coinstats.cpp:ApplyHash ) { LogPrintf("[snapshot] bad snapshot data after deserializing %d coins\n", coins_count - coins_left); return false; } coins_cache.EmplaceCoinInternalDANGER(std::move(outpoint), std::move(coin)); --coins_left; ++coins_processed; if (coins_processed % 1000000 == 0) { LogPrintf("[snapshot] %d coins loaded (%.2f%%, %.2f MB)\n", coins_processed, static_cast<float>(coins_processed) * 100 / static_cast<float>(coins_count), coins_cache.DynamicMemoryUsage() / (1000 * 1000)); } // Batch write and flush (if we need to) every so often. // // If our average Coin size is roughly 41 bytes, checking every 120,000 coins // means <5MB of memory imprecision. if (coins_processed % 120000 == 0) { if (ShutdownRequested()) { return false; } const auto snapshot_cache_state = WITH_LOCK(::cs_main, return snapshot_chainstate.GetCoinsCacheSizeState()); if (snapshot_cache_state >= CoinsCacheSizeState::CRITICAL) { // This is a hack - we don't know what the actual best block is, but that // doesn't matter for the purposes of flushing the cache here. We'll set this // to its correct value (`base_blockhash`) below after the coins are loaded. coins_cache.SetBestBlock(GetRandHash()); // No need to acquire cs_main since this chainstate isn't being used yet. FlushSnapshotToDisk(coins_cache, /*snapshot_loaded=*/false); } } } // Important that we set this. This and the coins_cache accesses above are // sort of a layer violation, but either we reach into the innards of // CCoinsViewCache here or we have to invert some of the Chainstate to // embed them in a snapshot-activation-specific CCoinsViewCache bulk load // method. coins_cache.SetBestBlock(base_blockhash); bool out_of_coins{false}; try { coins_file >> outpoint; } catch (const std::ios_base::failure&) { // We expect an exception since we should be out of coins. out_of_coins = true; } if (!out_of_coins) { LogPrintf("[snapshot] bad snapshot - coins left over after deserializing %d coins\n", coins_count); return false; } LogPrintf("[snapshot] loaded %d (%.2f MB) coins from snapshot %s\n", coins_count, coins_cache.DynamicMemoryUsage() / (1000 * 1000), base_blockhash.ToString()); // No need to acquire cs_main since this chainstate isn't being used yet. FlushSnapshotToDisk(coins_cache, /*snapshot_loaded=*/true); assert(coins_cache.GetBestBlock() == base_blockhash); auto breakpoint_fnc = [] { /* TODO insert breakpoint here? */ }; // As above, okay to immediately release cs_main here since no other context knows // about the snapshot_chainstate. CCoinsViewDB* snapshot_coinsdb = WITH_LOCK(::cs_main, return &snapshot_chainstate.CoinsDB()); const std::optional<CCoinsStats> maybe_stats = ComputeUTXOStats(CoinStatsHashType::HASH_SERIALIZED, snapshot_coinsdb, m_blockman, breakpoint_fnc); if (!maybe_stats.has_value()) { LogPrintf("[snapshot] failed to generate coins stats\n"); return false; } // Assert that the deserialized chainstate contents match the expected assumeutxo value. if (AssumeutxoHash{maybe_stats->hashSerialized} != au_data.hash_serialized) { LogPrintf("[snapshot] bad snapshot content hash: expected %s, got %s\n", au_data.hash_serialized.ToString(), maybe_stats->hashSerialized.ToString()); return false; } snapshot_chainstate.m_chain.SetTip(*snapshot_start_block); // The remainder of this function requires modifying data protected by cs_main. LOCK(::cs_main); // Fake various pieces of CBlockIndex state: CBlockIndex* index = nullptr; // Don't make any modifications to the genesis block. // This is especially important because we don't want to erroneously // apply BLOCK_ASSUMED_VALID to genesis, which would happen if we didn't skip // it here (since it apparently isn't BLOCK_VALID_SCRIPTS). constexpr int AFTER_GENESIS_START{1}; for (int i = AFTER_GENESIS_START; i <= snapshot_chainstate.m_chain.Height(); ++i) { index = snapshot_chainstate.m_chain[i]; // Fake nTx so that LoadBlockIndex() loads assumed-valid CBlockIndex // entries (among other things) if (!index->nTx) { index->nTx = 1; } // Fake nChainTx so that GuessVerificationProgress reports accurately index->nChainTx = index->pprev->nChainTx + index->nTx; // Mark unvalidated block index entries beneath the snapshot base block as assumed-valid. if (!index->IsValid(BLOCK_VALID_SCRIPTS)) { // This flag will be removed once the block is fully validated by a // background chainstate. index->nStatus |= BLOCK_ASSUMED_VALID; } // Fake BLOCK_OPT_WITNESS so that Chainstate::NeedsRedownload() // won't ask to rewind the entire assumed-valid chain on startup. if (DeploymentActiveAt(*index, *this, Consensus::DEPLOYMENT_SEGWIT)) { index->nStatus |= BLOCK_OPT_WITNESS; } m_blockman.m_dirty_blockindex.insert(index); // Changes to the block index will be flushed to disk after this call // returns in `ActivateSnapshot()`, when `MaybeRebalanceCaches()` is // called, since we've added a snapshot chainstate and therefore will // have to downsize the IBD chainstate, which will result in a call to // `FlushStateToDisk(ALWAYS)`. } assert(index); index->nChainTx = au_data.nChainTx; snapshot_chainstate.setBlockIndexCandidates.insert(snapshot_start_block); LogPrintf("[snapshot] validated snapshot (%.2f MB)\n", coins_cache.DynamicMemoryUsage() / (1000 * 1000)); return true; } Chainstate& ChainstateManager::ActiveChainstate() const { LOCK(::cs_main); assert(m_active_chainstate); return *m_active_chainstate; } bool ChainstateManager::IsSnapshotActive() const { LOCK(::cs_main); return m_snapshot_chainstate && m_active_chainstate == m_snapshot_chainstate.get(); } void ChainstateManager::MaybeRebalanceCaches() { AssertLockHeld(::cs_main); if (m_ibd_chainstate && !m_snapshot_chainstate) { LogPrintf("[snapshot] allocating all cache to the IBD chainstate\n"); // Allocate everything to the IBD chainstate. m_ibd_chainstate->ResizeCoinsCaches(m_total_coinstip_cache, m_total_coinsdb_cache); } else if (m_snapshot_chainstate && !m_ibd_chainstate) { LogPrintf("[snapshot] allocating all cache to the snapshot chainstate\n"); // Allocate everything to the snapshot chainstate. m_snapshot_chainstate->ResizeCoinsCaches(m_total_coinstip_cache, m_total_coinsdb_cache); } else if (m_ibd_chainstate && m_snapshot_chainstate) { // If both chainstates exist, determine who needs more cache based on IBD status. // // Note: shrink caches first so that we don't inadvertently overwhelm available memory. if (m_snapshot_chainstate->IsInitialBlockDownload()) { m_ibd_chainstate->ResizeCoinsCaches( m_total_coinstip_cache * 0.05, m_total_coinsdb_cache * 0.05); m_snapshot_chainstate->ResizeCoinsCaches( m_total_coinstip_cache * 0.95, m_total_coinsdb_cache * 0.95); } else { m_snapshot_chainstate->ResizeCoinsCaches( m_total_coinstip_cache * 0.05, m_total_coinsdb_cache * 0.05); m_ibd_chainstate->ResizeCoinsCaches( m_total_coinstip_cache * 0.95, m_total_coinsdb_cache * 0.95); } } } ChainstateManager::~ChainstateManager() { LOCK(::cs_main); m_versionbitscache.Clear(); // TODO: The warning cache should probably become non-global for (auto& i : warningcache) { i.clear(); } }