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bitcoin/src/txmempool.h

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// 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;
/** 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:
const int m_check_ratio; //!< Value n means that 1 times in n we check.
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
typedef boost::multi_index_container<
CTxMemPoolEntry,
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
>
>
> 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 int64_t m_max_size_bytes;
const std::chrono::seconds m_expiry;
const CFeeRate m_incremental_relay_feerate;
const CFeeRate m_min_relay_feerate;
const CFeeRate m_dust_relay_feerate;
const bool m_permit_bare_multisig;
const std::optional<unsigned> m_max_datacarrier_bytes;
const bool m_require_standard;
const bool m_full_rbf;
const bool m_persist_v1_dat;
const Limits m_limits;
ValidationSignals* const m_signals;
/** 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(const Options& opts);
/**
* 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_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
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