// Copyright (c) 2009-2010 Satoshi Nakamoto // Copyright (c) 2009-2022 The Bitcoin Core developers // Distributed under the MIT software license, see the accompanying // file COPYING or http://www.opensource.org/licenses/mit-license.php. #ifndef BITCOIN_TXMEMPOOL_H #define BITCOIN_TXMEMPOOL_H #include <coins.h> #include <consensus/amount.h> #include <indirectmap.h> #include <kernel/cs_main.h> #include <kernel/mempool_entry.h> // IWYU pragma: export #include <kernel/mempool_limits.h> // IWYU pragma: export #include <kernel/mempool_options.h> // IWYU pragma: export #include <kernel/mempool_removal_reason.h> // IWYU pragma: export #include <policy/feerate.h> #include <policy/packages.h> #include <primitives/transaction.h> #include <sync.h> #include <util/epochguard.h> #include <util/hasher.h> #include <util/result.h> #include <util/feefrac.h> #include <boost/multi_index/hashed_index.hpp> #include <boost/multi_index/identity.hpp> #include <boost/multi_index/indexed_by.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/sequenced_index.hpp> #include <boost/multi_index/tag.hpp> #include <boost/multi_index_container.hpp> #include <atomic> #include <map> #include <optional> #include <set> #include <string> #include <string_view> #include <utility> #include <vector> class CChain; class ValidationSignals; struct bilingual_str; /** Fake height value used in Coin to signify they are only in the memory pool (since 0.8) */ static const uint32_t MEMPOOL_HEIGHT = 0x7FFFFFFF; /** * Test whether the LockPoints height and time are still valid on the current chain */ bool TestLockPointValidity(CChain& active_chain, const LockPoints& lp) EXCLUSIVE_LOCKS_REQUIRED(cs_main); // extracts a transaction hash from CTxMemPoolEntry or CTransactionRef struct mempoolentry_txid { typedef uint256 result_type; result_type operator() (const CTxMemPoolEntry &entry) const { return entry.GetTx().GetHash(); } result_type operator() (const CTransactionRef& tx) const { return tx->GetHash(); } }; // extracts a transaction witness-hash from CTxMemPoolEntry or CTransactionRef struct mempoolentry_wtxid { typedef uint256 result_type; result_type operator() (const CTxMemPoolEntry &entry) const { return entry.GetTx().GetWitnessHash(); } result_type operator() (const CTransactionRef& tx) const { return tx->GetWitnessHash(); } }; /** \class CompareTxMemPoolEntryByDescendantScore * * Sort an entry by max(score/size of entry's tx, score/size with all descendants). */ class CompareTxMemPoolEntryByDescendantScore { public: bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const { double a_mod_fee, a_size, b_mod_fee, b_size; GetModFeeAndSize(a, a_mod_fee, a_size); GetModFeeAndSize(b, b_mod_fee, b_size); // Avoid division by rewriting (a/b > c/d) as (a*d > c*b). double f1 = a_mod_fee * b_size; double f2 = a_size * b_mod_fee; if (f1 == f2) { return a.GetTime() >= b.GetTime(); } return f1 < f2; } // Return the fee/size we're using for sorting this entry. void GetModFeeAndSize(const CTxMemPoolEntry &a, double &mod_fee, double &size) const { // Compare feerate with descendants to feerate of the transaction, and // return the fee/size for the max. double f1 = (double)a.GetModifiedFee() * a.GetSizeWithDescendants(); double f2 = (double)a.GetModFeesWithDescendants() * a.GetTxSize(); if (f2 > f1) { mod_fee = a.GetModFeesWithDescendants(); size = a.GetSizeWithDescendants(); } else { mod_fee = a.GetModifiedFee(); size = a.GetTxSize(); } } }; /** \class CompareTxMemPoolEntryByScore * * Sort by feerate of entry (fee/size) in descending order * This is only used for transaction relay, so we use GetFee() * instead of GetModifiedFee() to avoid leaking prioritization * information via the sort order. */ class CompareTxMemPoolEntryByScore { public: bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const { double f1 = (double)a.GetFee() * b.GetTxSize(); double f2 = (double)b.GetFee() * a.GetTxSize(); if (f1 == f2) { return b.GetTx().GetHash() < a.GetTx().GetHash(); } return f1 > f2; } }; class CompareTxMemPoolEntryByEntryTime { public: bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const { return a.GetTime() < b.GetTime(); } }; /** \class CompareTxMemPoolEntryByAncestorScore * * Sort an entry by min(score/size of entry's tx, score/size with all ancestors). */ class CompareTxMemPoolEntryByAncestorFee { public: template<typename T> bool operator()(const T& a, const T& b) const { double a_mod_fee, a_size, b_mod_fee, b_size; GetModFeeAndSize(a, a_mod_fee, a_size); GetModFeeAndSize(b, b_mod_fee, b_size); // Avoid division by rewriting (a/b > c/d) as (a*d > c*b). double f1 = a_mod_fee * b_size; double f2 = a_size * b_mod_fee; if (f1 == f2) { return a.GetTx().GetHash() < b.GetTx().GetHash(); } return f1 > f2; } // Return the fee/size we're using for sorting this entry. template <typename T> void GetModFeeAndSize(const T &a, double &mod_fee, double &size) const { // Compare feerate with ancestors to feerate of the transaction, and // return the fee/size for the min. double f1 = (double)a.GetModifiedFee() * a.GetSizeWithAncestors(); double f2 = (double)a.GetModFeesWithAncestors() * a.GetTxSize(); if (f1 > f2) { mod_fee = a.GetModFeesWithAncestors(); size = a.GetSizeWithAncestors(); } else { mod_fee = a.GetModifiedFee(); size = a.GetTxSize(); } } }; // Multi_index tag names struct descendant_score {}; struct entry_time {}; struct ancestor_score {}; struct index_by_wtxid {}; /** * Information about a mempool transaction. */ struct TxMempoolInfo { /** The transaction itself */ CTransactionRef tx; /** Time the transaction entered the mempool. */ std::chrono::seconds m_time; /** Fee of the transaction. */ CAmount fee; /** Virtual size of the transaction. */ int32_t vsize; /** The fee delta. */ int64_t nFeeDelta; }; /** * CTxMemPool stores valid-according-to-the-current-best-chain transactions * that may be included in the next block. * * Transactions are added when they are seen on the network (or created by the * local node), but not all transactions seen are added to the pool. For * example, the following new transactions will not be added to the mempool: * - a transaction which doesn't meet the minimum fee requirements. * - a new transaction that double-spends an input of a transaction already in * the pool where the new transaction does not meet the Replace-By-Fee * requirements as defined in doc/policy/mempool-replacements.md. * - a non-standard transaction. * * CTxMemPool::mapTx, and CTxMemPoolEntry bookkeeping: * * mapTx is a boost::multi_index that sorts the mempool on 5 criteria: * - transaction hash (txid) * - witness-transaction hash (wtxid) * - descendant feerate [we use max(feerate of tx, feerate of tx with all descendants)] * - time in mempool * - ancestor feerate [we use min(feerate of tx, feerate of tx with all unconfirmed ancestors)] * * Note: the term "descendant" refers to in-mempool transactions that depend on * this one, while "ancestor" refers to in-mempool transactions that a given * transaction depends on. * * In order for the feerate sort to remain correct, we must update transactions * in the mempool when new descendants arrive. To facilitate this, we track * the set of in-mempool direct parents and direct children in mapLinks. Within * each CTxMemPoolEntry, we track the size and fees of all descendants. * * Usually when a new transaction is added to the mempool, it has no in-mempool * children (because any such children would be an orphan). So in * addUnchecked(), we: * - update a new entry's setMemPoolParents to include all in-mempool parents * - update the new entry's direct parents to include the new tx as a child * - update all ancestors of the transaction to include the new tx's size/fee * * When a transaction is removed from the mempool, we must: * - update all in-mempool parents to not track the tx in setMemPoolChildren * - update all ancestors to not include the tx's size/fees in descendant state * - update all in-mempool children to not include it as a parent * * These happen in UpdateForRemoveFromMempool(). (Note that when removing a * transaction along with its descendants, we must calculate that set of * transactions to be removed before doing the removal, or else the mempool can * be in an inconsistent state where it's impossible to walk the ancestors of * a transaction.) * * In the event of a reorg, the assumption that a newly added tx has no * in-mempool children is false. In particular, the mempool is in an * inconsistent state while new transactions are being added, because there may * be descendant transactions of a tx coming from a disconnected block that are * unreachable from just looking at transactions in the mempool (the linking * transactions may also be in the disconnected block, waiting to be added). * Because of this, there's not much benefit in trying to search for in-mempool * children in addUnchecked(). Instead, in the special case of transactions * being added from a disconnected block, we require the caller to clean up the * state, to account for in-mempool, out-of-block descendants for all the * in-block transactions by calling UpdateTransactionsFromBlock(). Note that * until this is called, the mempool state is not consistent, and in particular * mapLinks may not be correct (and therefore functions like * CalculateMemPoolAncestors() and CalculateDescendants() that rely * on them to walk the mempool are not generally safe to use). * * Computational limits: * * Updating all in-mempool ancestors of a newly added transaction can be slow, * if no bound exists on how many in-mempool ancestors there may be. * CalculateMemPoolAncestors() takes configurable limits that are designed to * prevent these calculations from being too CPU intensive. * */ class CTxMemPool { protected: std::atomic<unsigned int> nTransactionsUpdated{0}; //!< Used by getblocktemplate to trigger CreateNewBlock() invocation uint64_t totalTxSize GUARDED_BY(cs){0}; //!< sum of all mempool tx's virtual sizes. Differs from serialized tx size since witness data is discounted. Defined in BIP 141. CAmount m_total_fee GUARDED_BY(cs){0}; //!< sum of all mempool tx's fees (NOT modified fee) uint64_t cachedInnerUsage GUARDED_BY(cs){0}; //!< sum of dynamic memory usage of all the map elements (NOT the maps themselves) mutable int64_t lastRollingFeeUpdate GUARDED_BY(cs){GetTime()}; mutable bool blockSinceLastRollingFeeBump GUARDED_BY(cs){false}; mutable double rollingMinimumFeeRate GUARDED_BY(cs){0}; //!< minimum fee to get into the pool, decreases exponentially mutable Epoch m_epoch GUARDED_BY(cs){}; // In-memory counter for external mempool tracking purposes. // This number is incremented once every time a transaction // is added or removed from the mempool for any reason. mutable uint64_t m_sequence_number GUARDED_BY(cs){1}; void trackPackageRemoved(const CFeeRate& rate) EXCLUSIVE_LOCKS_REQUIRED(cs); bool m_load_tried GUARDED_BY(cs){false}; CFeeRate GetMinFee(size_t sizelimit) const; public: static const int ROLLING_FEE_HALFLIFE = 60 * 60 * 12; // public only for testing struct CTxMemPoolEntry_Indices final : boost::multi_index::indexed_by< // sorted by txid boost::multi_index::hashed_unique<mempoolentry_txid, SaltedTxidHasher>, // sorted by wtxid boost::multi_index::hashed_unique< boost::multi_index::tag<index_by_wtxid>, mempoolentry_wtxid, SaltedTxidHasher >, // sorted by fee rate boost::multi_index::ordered_non_unique< boost::multi_index::tag<descendant_score>, boost::multi_index::identity<CTxMemPoolEntry>, CompareTxMemPoolEntryByDescendantScore >, // sorted by entry time boost::multi_index::ordered_non_unique< boost::multi_index::tag<entry_time>, boost::multi_index::identity<CTxMemPoolEntry>, CompareTxMemPoolEntryByEntryTime >, // sorted by fee rate with ancestors boost::multi_index::ordered_non_unique< boost::multi_index::tag<ancestor_score>, boost::multi_index::identity<CTxMemPoolEntry>, CompareTxMemPoolEntryByAncestorFee > > {}; typedef boost::multi_index_container< CTxMemPoolEntry, CTxMemPoolEntry_Indices > indexed_transaction_set; /** * This mutex needs to be locked when accessing `mapTx` or other members * that are guarded by it. * * @par Consistency guarantees * By design, it is guaranteed that: * 1. Locking both `cs_main` and `mempool.cs` will give a view of mempool * that is consistent with current chain tip (`ActiveChain()` and * `CoinsTip()`) and is fully populated. Fully populated means that if the * current active chain is missing transactions that were present in a * previously active chain, all the missing transactions will have been * re-added to the mempool and should be present if they meet size and * consistency constraints. * 2. Locking `mempool.cs` without `cs_main` will give a view of a mempool * consistent with some chain that was active since `cs_main` was last * locked, and that is fully populated as described above. It is ok for * code that only needs to query or remove transactions from the mempool * to lock just `mempool.cs` without `cs_main`. * * To provide these guarantees, it is necessary to lock both `cs_main` and * `mempool.cs` whenever adding transactions to the mempool and whenever * changing the chain tip. It's necessary to keep both mutexes locked until * the mempool is consistent with the new chain tip and fully populated. */ mutable RecursiveMutex cs; indexed_transaction_set mapTx GUARDED_BY(cs); using txiter = indexed_transaction_set::nth_index<0>::type::const_iterator; std::vector<CTransactionRef> txns_randomized GUARDED_BY(cs); //!< All transactions in mapTx, in random order typedef std::set<txiter, CompareIteratorByHash> setEntries; using Limits = kernel::MemPoolLimits; uint64_t CalculateDescendantMaximum(txiter entry) const EXCLUSIVE_LOCKS_REQUIRED(cs); private: typedef std::map<txiter, setEntries, CompareIteratorByHash> cacheMap; void UpdateParent(txiter entry, txiter parent, bool add) EXCLUSIVE_LOCKS_REQUIRED(cs); void UpdateChild(txiter entry, txiter child, bool add) EXCLUSIVE_LOCKS_REQUIRED(cs); std::vector<indexed_transaction_set::const_iterator> GetSortedDepthAndScore() const EXCLUSIVE_LOCKS_REQUIRED(cs); /** * Track locally submitted transactions to periodically retry initial broadcast. */ std::set<uint256> m_unbroadcast_txids GUARDED_BY(cs); /** * Helper function to calculate all in-mempool ancestors of staged_ancestors and apply ancestor * and descendant limits (including staged_ancestors themselves, entry_size and entry_count). * * @param[in] entry_size Virtual size to include in the limits. * @param[in] entry_count How many entries to include in the limits. * @param[in] staged_ancestors Should contain entries in the mempool. * @param[in] limits Maximum number and size of ancestors and descendants * * @return all in-mempool ancestors, or an error if any ancestor or descendant limits were hit */ util::Result<setEntries> CalculateAncestorsAndCheckLimits(int64_t entry_size, size_t entry_count, CTxMemPoolEntry::Parents &staged_ancestors, const Limits& limits ) const EXCLUSIVE_LOCKS_REQUIRED(cs); public: indirectmap<COutPoint, const CTransaction*> mapNextTx GUARDED_BY(cs); std::map<uint256, CAmount> mapDeltas GUARDED_BY(cs); using Options = kernel::MemPoolOptions; const Options m_opts; /** Create a new CTxMemPool. * Sanity checks will be off by default for performance, because otherwise * accepting transactions becomes O(N^2) where N is the number of transactions * in the pool. */ explicit CTxMemPool(Options opts, bilingual_str& error); /** * If sanity-checking is turned on, check makes sure the pool is * consistent (does not contain two transactions that spend the same inputs, * all inputs are in the mapNextTx array). If sanity-checking is turned off, * check does nothing. */ void check(const CCoinsViewCache& active_coins_tip, int64_t spendheight) const EXCLUSIVE_LOCKS_REQUIRED(::cs_main); // addUnchecked must updated state for all ancestors of a given transaction, // to track size/count of descendant transactions. First version of // addUnchecked can be used to have it call CalculateMemPoolAncestors(), and // then invoke the second version. // Note that addUnchecked is ONLY called from ATMP outside of tests // and any other callers may break wallet's in-mempool tracking (due to // lack of CValidationInterface::TransactionAddedToMempool callbacks). void addUnchecked(const CTxMemPoolEntry& entry) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main); void addUnchecked(const CTxMemPoolEntry& entry, setEntries& setAncestors) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main); void removeRecursive(const CTransaction& tx, MemPoolRemovalReason reason) EXCLUSIVE_LOCKS_REQUIRED(cs); /** After reorg, filter the entries that would no longer be valid in the next block, and update * the entries' cached LockPoints if needed. The mempool does not have any knowledge of * consensus rules. It just applies the callable function and removes the ones for which it * returns true. * @param[in] filter_final_and_mature Predicate that checks the relevant validation rules * and updates an entry's LockPoints. * */ void removeForReorg(CChain& chain, std::function<bool(txiter)> filter_final_and_mature) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main); void removeConflicts(const CTransaction& tx) EXCLUSIVE_LOCKS_REQUIRED(cs); void removeForBlock(const std::vector<CTransactionRef>& vtx, unsigned int nBlockHeight) EXCLUSIVE_LOCKS_REQUIRED(cs); bool CompareDepthAndScore(const uint256& hasha, const uint256& hashb, bool wtxid=false); bool isSpent(const COutPoint& outpoint) const; unsigned int GetTransactionsUpdated() const; void AddTransactionsUpdated(unsigned int n); /** * Check that none of this transactions inputs are in the mempool, and thus * the tx is not dependent on other mempool transactions to be included in a block. */ bool HasNoInputsOf(const CTransaction& tx) const EXCLUSIVE_LOCKS_REQUIRED(cs); /** Affect CreateNewBlock prioritisation of transactions */ void PrioritiseTransaction(const uint256& hash, const CAmount& nFeeDelta); void ApplyDelta(const uint256& hash, CAmount &nFeeDelta) const EXCLUSIVE_LOCKS_REQUIRED(cs); void ClearPrioritisation(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs); struct delta_info { /** Whether this transaction is in the mempool. */ const bool in_mempool; /** The fee delta added using PrioritiseTransaction(). */ const CAmount delta; /** The modified fee (base fee + delta) of this entry. Only present if in_mempool=true. */ std::optional<CAmount> modified_fee; /** The prioritised transaction's txid. */ const uint256 txid; }; /** Return a vector of all entries in mapDeltas with their corresponding delta_info. */ std::vector<delta_info> GetPrioritisedTransactions() const EXCLUSIVE_LOCKS_REQUIRED(!cs); /** Get the transaction in the pool that spends the same prevout */ const CTransaction* GetConflictTx(const COutPoint& prevout) const EXCLUSIVE_LOCKS_REQUIRED(cs); /** Returns an iterator to the given hash, if found */ std::optional<txiter> GetIter(const uint256& txid) const EXCLUSIVE_LOCKS_REQUIRED(cs); /** Translate a set of hashes into a set of pool iterators to avoid repeated lookups. * Does not require that all of the hashes correspond to actual transactions in the mempool, * only returns the ones that exist. */ setEntries GetIterSet(const std::set<Txid>& hashes) const EXCLUSIVE_LOCKS_REQUIRED(cs); /** Translate a list of hashes into a list of mempool iterators to avoid repeated lookups. * The nth element in txids becomes the nth element in the returned vector. If any of the txids * don't actually exist in the mempool, returns an empty vector. */ std::vector<txiter> GetIterVec(const std::vector<uint256>& txids) const EXCLUSIVE_LOCKS_REQUIRED(cs); /** Remove a set of transactions from the mempool. * If a transaction is in this set, then all in-mempool descendants must * also be in the set, unless this transaction is being removed for being * in a block. * Set updateDescendants to true when removing a tx that was in a block, so * that any in-mempool descendants have their ancestor state updated. */ void RemoveStaged(setEntries& stage, bool updateDescendants, MemPoolRemovalReason reason) EXCLUSIVE_LOCKS_REQUIRED(cs); /** UpdateTransactionsFromBlock is called when adding transactions from a * disconnected block back to the mempool, new mempool entries may have * children in the mempool (which is generally not the case when otherwise * adding transactions). * @post updated descendant state for descendants of each transaction in * vHashesToUpdate (excluding any child transactions present in * vHashesToUpdate, which are already accounted for). Updated state * includes add fee/size information for such descendants to the * parent and updated ancestor state to include the parent. * * @param[in] vHashesToUpdate The set of txids from the * disconnected block that have been accepted back into the mempool. */ void UpdateTransactionsFromBlock(const std::vector<uint256>& vHashesToUpdate) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main) LOCKS_EXCLUDED(m_epoch); /** * Try to calculate all in-mempool ancestors of entry. * (these are all calculated including the tx itself) * * @param[in] entry CTxMemPoolEntry of which all in-mempool ancestors are calculated * @param[in] limits Maximum number and size of ancestors and descendants * @param[in] fSearchForParents Whether to search a tx's vin for in-mempool parents, or look * up parents from mapLinks. Must be true for entries not in * the mempool * * @return all in-mempool ancestors, or an error if any ancestor or descendant limits were hit */ util::Result<setEntries> CalculateMemPoolAncestors(const CTxMemPoolEntry& entry, const Limits& limits, bool fSearchForParents = true) const EXCLUSIVE_LOCKS_REQUIRED(cs); /** * Same as CalculateMemPoolAncestors, but always returns a (non-optional) setEntries. * Should only be used when it is assumed CalculateMemPoolAncestors would not fail. If * CalculateMemPoolAncestors does unexpectedly fail, an empty setEntries is returned and the * error is logged to BCLog::MEMPOOL with level BCLog::Level::Error. In debug builds, failure * of CalculateMemPoolAncestors will lead to shutdown due to assertion failure. * * @param[in] calling_fn_name Name of calling function so we can properly log the call site * * @return a setEntries corresponding to the result of CalculateMemPoolAncestors or an empty * setEntries if it failed * * @see CTXMemPool::CalculateMemPoolAncestors() */ setEntries AssumeCalculateMemPoolAncestors( std::string_view calling_fn_name, const CTxMemPoolEntry &entry, const Limits& limits, bool fSearchForParents = true) const EXCLUSIVE_LOCKS_REQUIRED(cs); /** Collect the entire cluster of connected transactions for each transaction in txids. * All txids must correspond to transaction entries in the mempool, otherwise this returns an * empty vector. This call will also exit early and return an empty vector if it collects 500 or * more transactions as a DoS protection. */ std::vector<txiter> GatherClusters(const std::vector<uint256>& txids) const EXCLUSIVE_LOCKS_REQUIRED(cs); /** Calculate all in-mempool ancestors of a set of transactions not already in the mempool and * check ancestor and descendant limits. Heuristics are used to estimate the ancestor and * descendant count of all entries if the package were to be added to the mempool. The limits * are applied to the union of all package transactions. For example, if the package has 3 * transactions and limits.ancestor_count = 25, the union of all 3 sets of ancestors (including the * transactions themselves) must be <= 22. * @param[in] package Transaction package being evaluated for acceptance * to mempool. The transactions need not be direct * ancestors/descendants of each other. * @param[in] total_vsize Sum of virtual sizes for all transactions in package. * @returns {} or the error reason if a limit is hit. */ util::Result<void> CheckPackageLimits(const Package& package, int64_t total_vsize) const EXCLUSIVE_LOCKS_REQUIRED(cs); /** Populate setDescendants with all in-mempool descendants of hash. * Assumes that setDescendants includes all in-mempool descendants of anything * already in it. */ void CalculateDescendants(txiter it, setEntries& setDescendants) const EXCLUSIVE_LOCKS_REQUIRED(cs); /** The minimum fee to get into the mempool, which may itself not be enough * for larger-sized transactions. * The m_incremental_relay_feerate policy variable is used to bound the time it * takes the fee rate to go back down all the way to 0. When the feerate * would otherwise be half of this, it is set to 0 instead. */ CFeeRate GetMinFee() const { return GetMinFee(m_opts.max_size_bytes); } /** Remove transactions from the mempool until its dynamic size is <= sizelimit. * pvNoSpendsRemaining, if set, will be populated with the list of outpoints * which are not in mempool which no longer have any spends in this mempool. */ void TrimToSize(size_t sizelimit, std::vector<COutPoint>* pvNoSpendsRemaining = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs); /** Expire all transaction (and their dependencies) in the mempool older than time. Return the number of removed transactions. */ int Expire(std::chrono::seconds time) EXCLUSIVE_LOCKS_REQUIRED(cs); /** * Calculate the ancestor and descendant count for the given transaction. * The counts include the transaction itself. * When ancestors is non-zero (ie, the transaction itself is in the mempool), * ancestorsize and ancestorfees will also be set to the appropriate values. */ void GetTransactionAncestry(const uint256& txid, size_t& ancestors, size_t& descendants, size_t* ancestorsize = nullptr, CAmount* ancestorfees = nullptr) const; /** * @returns true if an initial attempt to load the persisted mempool was made, regardless of * whether the attempt was successful or not */ bool GetLoadTried() const; /** * Set whether or not an initial attempt to load the persisted mempool was made (regardless * of whether the attempt was successful or not) */ void SetLoadTried(bool load_tried); unsigned long size() const { LOCK(cs); return mapTx.size(); } uint64_t GetTotalTxSize() const EXCLUSIVE_LOCKS_REQUIRED(cs) { AssertLockHeld(cs); return totalTxSize; } CAmount GetTotalFee() const EXCLUSIVE_LOCKS_REQUIRED(cs) { AssertLockHeld(cs); return m_total_fee; } bool exists(const GenTxid& gtxid) const { LOCK(cs); if (gtxid.IsWtxid()) { return (mapTx.get<index_by_wtxid>().count(gtxid.GetHash()) != 0); } return (mapTx.count(gtxid.GetHash()) != 0); } const CTxMemPoolEntry* GetEntry(const Txid& txid) const LIFETIMEBOUND EXCLUSIVE_LOCKS_REQUIRED(cs); CTransactionRef get(const uint256& hash) const; txiter get_iter_from_wtxid(const uint256& wtxid) const EXCLUSIVE_LOCKS_REQUIRED(cs) { AssertLockHeld(cs); return mapTx.project<0>(mapTx.get<index_by_wtxid>().find(wtxid)); } TxMempoolInfo info(const GenTxid& gtxid) const; /** Returns info for a transaction if its entry_sequence < last_sequence */ TxMempoolInfo info_for_relay(const GenTxid& gtxid, uint64_t last_sequence) const; std::vector<CTxMemPoolEntryRef> entryAll() const EXCLUSIVE_LOCKS_REQUIRED(cs); std::vector<TxMempoolInfo> infoAll() const; size_t DynamicMemoryUsage() const; /** Adds a transaction to the unbroadcast set */ void AddUnbroadcastTx(const uint256& txid) { LOCK(cs); // Sanity check the transaction is in the mempool & insert into // unbroadcast set. if (exists(GenTxid::Txid(txid))) m_unbroadcast_txids.insert(txid); }; /** Removes a transaction from the unbroadcast set */ void RemoveUnbroadcastTx(const uint256& txid, const bool unchecked = false); /** Returns transactions in unbroadcast set */ std::set<uint256> GetUnbroadcastTxs() const { LOCK(cs); return m_unbroadcast_txids; } /** Returns whether a txid is in the unbroadcast set */ bool IsUnbroadcastTx(const uint256& txid) const EXCLUSIVE_LOCKS_REQUIRED(cs) { AssertLockHeld(cs); return m_unbroadcast_txids.count(txid) != 0; } /** Guards this internal counter for external reporting */ uint64_t GetAndIncrementSequence() const EXCLUSIVE_LOCKS_REQUIRED(cs) { return m_sequence_number++; } uint64_t GetSequence() const EXCLUSIVE_LOCKS_REQUIRED(cs) { return m_sequence_number; } /** * Calculate the sorted chunks for the old and new mempool relating to the * clusters that would be affected by a potential replacement transaction. * (replacement_fees, replacement_vsize) values are gathered from a * proposed set of replacement transactions that are considered as a single * chunk, and represent their complete cluster. In other words, they have no * in-mempool ancestors. * * @param[in] replacement_fees Package fees * @param[in] replacement_vsize Package size (must be greater than 0) * @param[in] direct_conflicts All transactions that would be removed directly by * having a conflicting input with a proposed transaction * @param[in] all_conflicts All transactions that would be removed * @return old and new diagram pair respectively, or an error string if the conflicts don't match a calculable topology */ util::Result<std::pair<std::vector<FeeFrac>, std::vector<FeeFrac>>> CalculateChunksForRBF(CAmount replacement_fees, int64_t replacement_vsize, const setEntries& direct_conflicts, const setEntries& all_conflicts) EXCLUSIVE_LOCKS_REQUIRED(cs); /* Check that all direct conflicts are in a cluster size of two or less. Each * direct conflict may be in a separate cluster. */ std::optional<std::string> CheckConflictTopology(const setEntries& direct_conflicts); private: /** UpdateForDescendants is used by UpdateTransactionsFromBlock to update * the descendants for a single transaction that has been added to the * mempool but may have child transactions in the mempool, eg during a * chain reorg. * * @pre CTxMemPoolEntry::m_children is correct for the given tx and all * descendants. * @pre cachedDescendants is an accurate cache where each entry has all * descendants of the corresponding key, including those that should * be removed for violation of ancestor limits. * @post if updateIt has any non-excluded descendants, cachedDescendants has * a new cache line for updateIt. * @post descendants_to_remove has a new entry for any descendant which exceeded * ancestor limits relative to updateIt. * * @param[in] updateIt the entry to update for its descendants * @param[in,out] cachedDescendants a cache where each line corresponds to all * descendants. It will be updated with the descendants of the transaction * being updated, so that future invocations don't need to walk the same * transaction again, if encountered in another transaction chain. * @param[in] setExclude the set of descendant transactions in the mempool * that must not be accounted for (because any descendants in setExclude * were added to the mempool after the transaction being updated and hence * their state is already reflected in the parent state). * @param[out] descendants_to_remove Populated with the txids of entries that * exceed ancestor limits. It's the responsibility of the caller to * removeRecursive them. */ void UpdateForDescendants(txiter updateIt, cacheMap& cachedDescendants, const std::set<uint256>& setExclude, std::set<uint256>& descendants_to_remove) EXCLUSIVE_LOCKS_REQUIRED(cs); /** Update ancestors of hash to add/remove it as a descendant transaction. */ void UpdateAncestorsOf(bool add, txiter hash, setEntries &setAncestors) EXCLUSIVE_LOCKS_REQUIRED(cs); /** Set ancestor state for an entry */ void UpdateEntryForAncestors(txiter it, const setEntries &setAncestors) EXCLUSIVE_LOCKS_REQUIRED(cs); /** For each transaction being removed, update ancestors and any direct children. * If updateDescendants is true, then also update in-mempool descendants' * ancestor state. */ void UpdateForRemoveFromMempool(const setEntries &entriesToRemove, bool updateDescendants) EXCLUSIVE_LOCKS_REQUIRED(cs); /** Sever link between specified transaction and direct children. */ void UpdateChildrenForRemoval(txiter entry) EXCLUSIVE_LOCKS_REQUIRED(cs); /** Before calling removeUnchecked for a given transaction, * UpdateForRemoveFromMempool must be called on the entire (dependent) set * of transactions being removed at the same time. We use each * CTxMemPoolEntry's setMemPoolParents in order to walk ancestors of a * given transaction that is removed, so we can't remove intermediate * transactions in a chain before we've updated all the state for the * removal. */ void removeUnchecked(txiter entry, MemPoolRemovalReason reason) EXCLUSIVE_LOCKS_REQUIRED(cs); public: /** visited marks a CTxMemPoolEntry as having been traversed * during the lifetime of the most recently created Epoch::Guard * and returns false if we are the first visitor, true otherwise. * * An Epoch::Guard must be held when visited is called or an assert will be * triggered. * */ bool visited(const txiter it) const EXCLUSIVE_LOCKS_REQUIRED(cs, m_epoch) { return m_epoch.visited(it->m_epoch_marker); } bool visited(std::optional<txiter> it) const EXCLUSIVE_LOCKS_REQUIRED(cs, m_epoch) { assert(m_epoch.guarded()); // verify guard even when it==nullopt return !it || visited(*it); } }; /** * CCoinsView that brings transactions from a mempool into view. * It does not check for spendings by memory pool transactions. * Instead, it provides access to all Coins which are either unspent in the * base CCoinsView, are outputs from any mempool transaction, or are * tracked temporarily to allow transaction dependencies in package validation. * This allows transaction replacement to work as expected, as you want to * have all inputs "available" to check signatures, and any cycles in the * dependency graph are checked directly in AcceptToMemoryPool. * It also allows you to sign a double-spend directly in * signrawtransactionwithkey and signrawtransactionwithwallet, * as long as the conflicting transaction is not yet confirmed. */ class CCoinsViewMemPool : public CCoinsViewBacked { /** * Coins made available by transactions being validated. Tracking these allows for package * validation, since we can access transaction outputs without submitting them to mempool. */ std::unordered_map<COutPoint, Coin, SaltedOutpointHasher> m_temp_added; /** * Set of all coins that have been fetched from mempool or created using PackageAddTransaction * (not base). Used to track the origin of a coin, see GetNonBaseCoins(). */ mutable std::unordered_set<COutPoint, SaltedOutpointHasher> m_non_base_coins; protected: const CTxMemPool& mempool; public: CCoinsViewMemPool(CCoinsView* baseIn, const CTxMemPool& mempoolIn); /** GetCoin, returning whether it exists and is not spent. Also updates m_non_base_coins if the * coin is not fetched from base. */ bool GetCoin(const COutPoint &outpoint, Coin &coin) const override; /** Add the coins created by this transaction. These coins are only temporarily stored in * m_temp_added and cannot be flushed to the back end. Only used for package validation. */ void PackageAddTransaction(const CTransactionRef& tx); /** Get all coins in m_non_base_coins. */ std::unordered_set<COutPoint, SaltedOutpointHasher> GetNonBaseCoins() const { return m_non_base_coins; } /** Clear m_temp_added and m_non_base_coins. */ void Reset(); }; #endif // BITCOIN_TXMEMPOOL_H