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1 : : // Copyright (c) 2009-2010 Satoshi Nakamoto
2 : : // Copyright (c) 2009-2022 The Bitcoin Core developers
3 : : // Distributed under the MIT software license, see the accompanying
4 : : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
5 : :
6 : : #ifndef BITCOIN_TXMEMPOOL_H
7 : : #define BITCOIN_TXMEMPOOL_H
8 : :
9 : : #include <coins.h>
10 : : #include <consensus/amount.h>
11 : : #include <indirectmap.h>
12 : : #include <kernel/cs_main.h>
13 : : #include <kernel/mempool_entry.h> // IWYU pragma: export
14 : : #include <kernel/mempool_limits.h> // IWYU pragma: export
15 : : #include <kernel/mempool_options.h> // IWYU pragma: export
16 : : #include <kernel/mempool_removal_reason.h> // IWYU pragma: export
17 : : #include <policy/feerate.h>
18 : : #include <policy/packages.h>
19 : : #include <primitives/transaction.h>
20 : : #include <sync.h>
21 : : #include <util/epochguard.h>
22 : : #include <util/hasher.h>
23 : : #include <util/result.h>
24 : : #include <util/feefrac.h>
25 : :
26 : : #include <boost/multi_index/hashed_index.hpp>
27 : : #include <boost/multi_index/identity.hpp>
28 : : #include <boost/multi_index/indexed_by.hpp>
29 : : #include <boost/multi_index/ordered_index.hpp>
30 : : #include <boost/multi_index/sequenced_index.hpp>
31 : : #include <boost/multi_index/tag.hpp>
32 : : #include <boost/multi_index_container.hpp>
33 : :
34 : : #include <atomic>
35 : : #include <map>
36 : : #include <optional>
37 : : #include <set>
38 : : #include <string>
39 : : #include <string_view>
40 : : #include <utility>
41 : : #include <vector>
42 : :
43 : : class CChain;
44 : : class ValidationSignals;
45 : :
46 : : /** Fake height value used in Coin to signify they are only in the memory pool (since 0.8) */
47 : : static const uint32_t MEMPOOL_HEIGHT = 0x7FFFFFFF;
48 : :
49 : : /**
50 : : * Test whether the LockPoints height and time are still valid on the current chain
51 : : */
52 : : bool TestLockPointValidity(CChain& active_chain, const LockPoints& lp) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
53 : :
54 : : // extracts a transaction hash from CTxMemPoolEntry or CTransactionRef
55 : : struct mempoolentry_txid
56 : : {
57 : : typedef uint256 result_type;
58 : 58877439 : result_type operator() (const CTxMemPoolEntry &entry) const
59 : : {
60 : 58877439 : return entry.GetTx().GetHash();
61 : : }
62 : :
63 : : result_type operator() (const CTransactionRef& tx) const
64 : : {
65 : : return tx->GetHash();
66 : : }
67 : : };
68 : :
69 : : // extracts a transaction witness-hash from CTxMemPoolEntry or CTransactionRef
70 : : struct mempoolentry_wtxid
71 : : {
72 : : typedef uint256 result_type;
73 : 43301669 : result_type operator() (const CTxMemPoolEntry &entry) const
74 : : {
75 : 43301669 : return entry.GetTx().GetWitnessHash();
76 : : }
77 : :
78 : : result_type operator() (const CTransactionRef& tx) const
79 : : {
80 : : return tx->GetWitnessHash();
81 : : }
82 : : };
83 : :
84 : :
85 : : /** \class CompareTxMemPoolEntryByDescendantScore
86 : : *
87 : : * Sort an entry by max(score/size of entry's tx, score/size with all descendants).
88 : : */
89 : : class CompareTxMemPoolEntryByDescendantScore
90 : : {
91 : : public:
92 : 151579730 : bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const
93 : : {
94 : 151579730 : double a_mod_fee, a_size, b_mod_fee, b_size;
95 : :
96 : 151579730 : GetModFeeAndSize(a, a_mod_fee, a_size);
97 : 151579730 : GetModFeeAndSize(b, b_mod_fee, b_size);
98 : :
99 : : // Avoid division by rewriting (a/b > c/d) as (a*d > c*b).
100 : 151579730 : double f1 = a_mod_fee * b_size;
101 : 151579730 : double f2 = a_size * b_mod_fee;
102 : :
103 [ + + ]: 151579730 : if (f1 == f2) {
104 : 77382426 : return a.GetTime() >= b.GetTime();
105 : : }
106 : 74197304 : return f1 < f2;
107 : 151579730 : }
108 : :
109 : : // Return the fee/size we're using for sorting this entry.
110 : 303159460 : void GetModFeeAndSize(const CTxMemPoolEntry &a, double &mod_fee, double &size) const
111 : : {
112 : : // Compare feerate with descendants to feerate of the transaction, and
113 : : // return the fee/size for the max.
114 : 303159460 : double f1 = (double)a.GetModifiedFee() * a.GetSizeWithDescendants();
115 : 303159460 : double f2 = (double)a.GetModFeesWithDescendants() * a.GetTxSize();
116 : :
117 [ + + ]: 303159460 : if (f2 > f1) {
118 : 95296260 : mod_fee = a.GetModFeesWithDescendants();
119 : 95296260 : size = a.GetSizeWithDescendants();
120 : 95296260 : } else {
121 : 207863200 : mod_fee = a.GetModifiedFee();
122 : 207863200 : size = a.GetTxSize();
123 : : }
124 : 303159460 : }
125 : : };
126 : :
127 : : /** \class CompareTxMemPoolEntryByScore
128 : : *
129 : : * Sort by feerate of entry (fee/size) in descending order
130 : : * This is only used for transaction relay, so we use GetFee()
131 : : * instead of GetModifiedFee() to avoid leaking prioritization
132 : : * information via the sort order.
133 : : */
134 : : class CompareTxMemPoolEntryByScore
135 : : {
136 : : public:
137 : 4349437 : bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const
138 : : {
139 : 4349437 : double f1 = (double)a.GetFee() * b.GetTxSize();
140 : 4349437 : double f2 = (double)b.GetFee() * a.GetTxSize();
141 [ + + ]: 4349437 : if (f1 == f2) {
142 : 2488885 : return b.GetTx().GetHash() < a.GetTx().GetHash();
143 : : }
144 : 1860552 : return f1 > f2;
145 : 4349437 : }
146 : : };
147 : :
148 : : class CompareTxMemPoolEntryByEntryTime
149 : : {
150 : : public:
151 : 37285679 : bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const
152 : : {
153 : 37285679 : return a.GetTime() < b.GetTime();
154 : : }
155 : : };
156 : :
157 : : /** \class CompareTxMemPoolEntryByAncestorScore
158 : : *
159 : : * Sort an entry by min(score/size of entry's tx, score/size with all ancestors).
160 : : */
161 : : class CompareTxMemPoolEntryByAncestorFee
162 : : {
163 : : public:
164 : : template<typename T>
165 : 38014951 : bool operator()(const T& a, const T& b) const
166 : : {
167 : 38014951 : double a_mod_fee, a_size, b_mod_fee, b_size;
168 : :
169 : 38014951 : GetModFeeAndSize(a, a_mod_fee, a_size);
170 : 38014951 : GetModFeeAndSize(b, b_mod_fee, b_size);
171 : :
172 : : // Avoid division by rewriting (a/b > c/d) as (a*d > c*b).
173 : 38014951 : double f1 = a_mod_fee * b_size;
174 : 38014951 : double f2 = a_size * b_mod_fee;
175 : :
176 [ + + ]: 38014951 : if (f1 == f2) {
177 : 15188719 : return a.GetTx().GetHash() < b.GetTx().GetHash();
178 : : }
179 : 22826232 : return f1 > f2;
180 : 38014951 : }
181 : :
182 : : // Return the fee/size we're using for sorting this entry.
183 : : template <typename T>
184 : 76029902 : void GetModFeeAndSize(const T &a, double &mod_fee, double &size) const
185 : : {
186 : : // Compare feerate with ancestors to feerate of the transaction, and
187 : : // return the fee/size for the min.
188 : 76029902 : double f1 = (double)a.GetModifiedFee() * a.GetSizeWithAncestors();
189 : 76029902 : double f2 = (double)a.GetModFeesWithAncestors() * a.GetTxSize();
190 : :
191 [ + + ]: 76029902 : if (f1 > f2) {
192 : 38110792 : mod_fee = a.GetModFeesWithAncestors();
193 : 38110792 : size = a.GetSizeWithAncestors();
194 : 38110792 : } else {
195 : 37919110 : mod_fee = a.GetModifiedFee();
196 : 37919110 : size = a.GetTxSize();
197 : : }
198 : 76029902 : }
199 : : };
200 : :
201 : : // Multi_index tag names
202 : : struct descendant_score {};
203 : : struct entry_time {};
204 : : struct ancestor_score {};
205 : : struct index_by_wtxid {};
206 : :
207 : : /**
208 : : * Information about a mempool transaction.
209 : : */
210 : : struct TxMempoolInfo
211 : : {
212 : : /** The transaction itself */
213 : : CTransactionRef tx;
214 : :
215 : : /** Time the transaction entered the mempool. */
216 : : std::chrono::seconds m_time;
217 : :
218 : : /** Fee of the transaction. */
219 : : CAmount fee;
220 : :
221 : : /** Virtual size of the transaction. */
222 : : int32_t vsize;
223 : :
224 : : /** The fee delta. */
225 : : int64_t nFeeDelta;
226 : : };
227 : :
228 : : /**
229 : : * CTxMemPool stores valid-according-to-the-current-best-chain transactions
230 : : * that may be included in the next block.
231 : : *
232 : : * Transactions are added when they are seen on the network (or created by the
233 : : * local node), but not all transactions seen are added to the pool. For
234 : : * example, the following new transactions will not be added to the mempool:
235 : : * - a transaction which doesn't meet the minimum fee requirements.
236 : : * - a new transaction that double-spends an input of a transaction already in
237 : : * the pool where the new transaction does not meet the Replace-By-Fee
238 : : * requirements as defined in doc/policy/mempool-replacements.md.
239 : : * - a non-standard transaction.
240 : : *
241 : : * CTxMemPool::mapTx, and CTxMemPoolEntry bookkeeping:
242 : : *
243 : : * mapTx is a boost::multi_index that sorts the mempool on 5 criteria:
244 : : * - transaction hash (txid)
245 : : * - witness-transaction hash (wtxid)
246 : : * - descendant feerate [we use max(feerate of tx, feerate of tx with all descendants)]
247 : : * - time in mempool
248 : : * - ancestor feerate [we use min(feerate of tx, feerate of tx with all unconfirmed ancestors)]
249 : : *
250 : : * Note: the term "descendant" refers to in-mempool transactions that depend on
251 : : * this one, while "ancestor" refers to in-mempool transactions that a given
252 : : * transaction depends on.
253 : : *
254 : : * In order for the feerate sort to remain correct, we must update transactions
255 : : * in the mempool when new descendants arrive. To facilitate this, we track
256 : : * the set of in-mempool direct parents and direct children in mapLinks. Within
257 : : * each CTxMemPoolEntry, we track the size and fees of all descendants.
258 : : *
259 : : * Usually when a new transaction is added to the mempool, it has no in-mempool
260 : : * children (because any such children would be an orphan). So in
261 : : * addUnchecked(), we:
262 : : * - update a new entry's setMemPoolParents to include all in-mempool parents
263 : : * - update the new entry's direct parents to include the new tx as a child
264 : : * - update all ancestors of the transaction to include the new tx's size/fee
265 : : *
266 : : * When a transaction is removed from the mempool, we must:
267 : : * - update all in-mempool parents to not track the tx in setMemPoolChildren
268 : : * - update all ancestors to not include the tx's size/fees in descendant state
269 : : * - update all in-mempool children to not include it as a parent
270 : : *
271 : : * These happen in UpdateForRemoveFromMempool(). (Note that when removing a
272 : : * transaction along with its descendants, we must calculate that set of
273 : : * transactions to be removed before doing the removal, or else the mempool can
274 : : * be in an inconsistent state where it's impossible to walk the ancestors of
275 : : * a transaction.)
276 : : *
277 : : * In the event of a reorg, the assumption that a newly added tx has no
278 : : * in-mempool children is false. In particular, the mempool is in an
279 : : * inconsistent state while new transactions are being added, because there may
280 : : * be descendant transactions of a tx coming from a disconnected block that are
281 : : * unreachable from just looking at transactions in the mempool (the linking
282 : : * transactions may also be in the disconnected block, waiting to be added).
283 : : * Because of this, there's not much benefit in trying to search for in-mempool
284 : : * children in addUnchecked(). Instead, in the special case of transactions
285 : : * being added from a disconnected block, we require the caller to clean up the
286 : : * state, to account for in-mempool, out-of-block descendants for all the
287 : : * in-block transactions by calling UpdateTransactionsFromBlock(). Note that
288 : : * until this is called, the mempool state is not consistent, and in particular
289 : : * mapLinks may not be correct (and therefore functions like
290 : : * CalculateMemPoolAncestors() and CalculateDescendants() that rely
291 : : * on them to walk the mempool are not generally safe to use).
292 : : *
293 : : * Computational limits:
294 : : *
295 : : * Updating all in-mempool ancestors of a newly added transaction can be slow,
296 : : * if no bound exists on how many in-mempool ancestors there may be.
297 : : * CalculateMemPoolAncestors() takes configurable limits that are designed to
298 : : * prevent these calculations from being too CPU intensive.
299 : : *
300 : : */
301 : : class CTxMemPool
302 : : {
303 : : protected:
304 : : std::atomic<unsigned int> nTransactionsUpdated{0}; //!< Used by getblocktemplate to trigger CreateNewBlock() invocation
305 : :
306 : : 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.
307 : : CAmount m_total_fee GUARDED_BY(cs){0}; //!< sum of all mempool tx's fees (NOT modified fee)
308 : : uint64_t cachedInnerUsage GUARDED_BY(cs){0}; //!< sum of dynamic memory usage of all the map elements (NOT the maps themselves)
309 : :
310 : : mutable int64_t lastRollingFeeUpdate GUARDED_BY(cs){GetTime()};
311 : : mutable bool blockSinceLastRollingFeeBump GUARDED_BY(cs){false};
312 : : mutable double rollingMinimumFeeRate GUARDED_BY(cs){0}; //!< minimum fee to get into the pool, decreases exponentially
313 : : mutable Epoch m_epoch GUARDED_BY(cs){};
314 : :
315 : : // In-memory counter for external mempool tracking purposes.
316 : : // This number is incremented once every time a transaction
317 : : // is added or removed from the mempool for any reason.
318 : : mutable uint64_t m_sequence_number GUARDED_BY(cs){1};
319 : :
320 : : void trackPackageRemoved(const CFeeRate& rate) EXCLUSIVE_LOCKS_REQUIRED(cs);
321 : :
322 : : bool m_load_tried GUARDED_BY(cs){false};
323 : :
324 : : CFeeRate GetMinFee(size_t sizelimit) const;
325 : :
326 : : public:
327 : :
328 : : static const int ROLLING_FEE_HALFLIFE = 60 * 60 * 12; // public only for testing
329 : :
330 : : typedef boost::multi_index_container<
331 : : CTxMemPoolEntry,
332 : : boost::multi_index::indexed_by<
333 : : // sorted by txid
334 : : boost::multi_index::hashed_unique<mempoolentry_txid, SaltedTxidHasher>,
335 : : // sorted by wtxid
336 : : boost::multi_index::hashed_unique<
337 : : boost::multi_index::tag<index_by_wtxid>,
338 : : mempoolentry_wtxid,
339 : : SaltedTxidHasher
340 : : >,
341 : : // sorted by fee rate
342 : : boost::multi_index::ordered_non_unique<
343 : : boost::multi_index::tag<descendant_score>,
344 : : boost::multi_index::identity<CTxMemPoolEntry>,
345 : : CompareTxMemPoolEntryByDescendantScore
346 : : >,
347 : : // sorted by entry time
348 : : boost::multi_index::ordered_non_unique<
349 : : boost::multi_index::tag<entry_time>,
350 : : boost::multi_index::identity<CTxMemPoolEntry>,
351 : : CompareTxMemPoolEntryByEntryTime
352 : : >,
353 : : // sorted by fee rate with ancestors
354 : : boost::multi_index::ordered_non_unique<
355 : : boost::multi_index::tag<ancestor_score>,
356 : : boost::multi_index::identity<CTxMemPoolEntry>,
357 : : CompareTxMemPoolEntryByAncestorFee
358 : : >
359 : : >
360 : : > indexed_transaction_set;
361 : :
362 : : /**
363 : : * This mutex needs to be locked when accessing `mapTx` or other members
364 : : * that are guarded by it.
365 : : *
366 : : * @par Consistency guarantees
367 : : *
368 : : * By design, it is guaranteed that:
369 : : *
370 : : * 1. Locking both `cs_main` and `mempool.cs` will give a view of mempool
371 : : * that is consistent with current chain tip (`ActiveChain()` and
372 : : * `CoinsTip()`) and is fully populated. Fully populated means that if the
373 : : * current active chain is missing transactions that were present in a
374 : : * previously active chain, all the missing transactions will have been
375 : : * re-added to the mempool and should be present if they meet size and
376 : : * consistency constraints.
377 : : *
378 : : * 2. Locking `mempool.cs` without `cs_main` will give a view of a mempool
379 : : * consistent with some chain that was active since `cs_main` was last
380 : : * locked, and that is fully populated as described above. It is ok for
381 : : * code that only needs to query or remove transactions from the mempool
382 : : * to lock just `mempool.cs` without `cs_main`.
383 : : *
384 : : * To provide these guarantees, it is necessary to lock both `cs_main` and
385 : : * `mempool.cs` whenever adding transactions to the mempool and whenever
386 : : * changing the chain tip. It's necessary to keep both mutexes locked until
387 : : * the mempool is consistent with the new chain tip and fully populated.
388 : : */
389 : : mutable RecursiveMutex cs;
390 : : indexed_transaction_set mapTx GUARDED_BY(cs);
391 : :
392 : : using txiter = indexed_transaction_set::nth_index<0>::type::const_iterator;
393 : : std::vector<CTransactionRef> txns_randomized GUARDED_BY(cs); //!< All transactions in mapTx, in random order
394 : :
395 : : typedef std::set<txiter, CompareIteratorByHash> setEntries;
396 : :
397 : : using Limits = kernel::MemPoolLimits;
398 : :
399 : : uint64_t CalculateDescendantMaximum(txiter entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
400 : : private:
401 : : typedef std::map<txiter, setEntries, CompareIteratorByHash> cacheMap;
402 : :
403 : :
404 : : void UpdateParent(txiter entry, txiter parent, bool add) EXCLUSIVE_LOCKS_REQUIRED(cs);
405 : : void UpdateChild(txiter entry, txiter child, bool add) EXCLUSIVE_LOCKS_REQUIRED(cs);
406 : :
407 : : std::vector<indexed_transaction_set::const_iterator> GetSortedDepthAndScore() const EXCLUSIVE_LOCKS_REQUIRED(cs);
408 : :
409 : : /**
410 : : * Track locally submitted transactions to periodically retry initial broadcast.
411 : : */
412 : : std::set<uint256> m_unbroadcast_txids GUARDED_BY(cs);
413 : :
414 : :
415 : : /**
416 : : * Helper function to calculate all in-mempool ancestors of staged_ancestors and apply ancestor
417 : : * and descendant limits (including staged_ancestors themselves, entry_size and entry_count).
418 : : *
419 : : * @param[in] entry_size Virtual size to include in the limits.
420 : : * @param[in] entry_count How many entries to include in the limits.
421 : : * @param[in] staged_ancestors Should contain entries in the mempool.
422 : : * @param[in] limits Maximum number and size of ancestors and descendants
423 : : *
424 : : * @return all in-mempool ancestors, or an error if any ancestor or descendant limits were hit
425 : : */
426 : : util::Result<setEntries> CalculateAncestorsAndCheckLimits(int64_t entry_size,
427 : : size_t entry_count,
428 : : CTxMemPoolEntry::Parents &staged_ancestors,
429 : : const Limits& limits
430 : : ) const EXCLUSIVE_LOCKS_REQUIRED(cs);
431 : :
432 : : public:
433 : : indirectmap<COutPoint, const CTransaction*> mapNextTx GUARDED_BY(cs);
434 : : std::map<uint256, CAmount> mapDeltas GUARDED_BY(cs);
435 : :
436 : : using Options = kernel::MemPoolOptions;
437 : :
438 : : const Options m_opts;
439 : :
440 : : /** Create a new CTxMemPool.
441 : : * Sanity checks will be off by default for performance, because otherwise
442 : : * accepting transactions becomes O(N^2) where N is the number of transactions
443 : : * in the pool.
444 : : */
445 : : explicit CTxMemPool(const Options& opts);
446 : :
447 : : /**
448 : : * If sanity-checking is turned on, check makes sure the pool is
449 : : * consistent (does not contain two transactions that spend the same inputs,
450 : : * all inputs are in the mapNextTx array). If sanity-checking is turned off,
451 : : * check does nothing.
452 : : */
453 : : void check(const CCoinsViewCache& active_coins_tip, int64_t spendheight) const EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
454 : :
455 : : // addUnchecked must updated state for all ancestors of a given transaction,
456 : : // to track size/count of descendant transactions. First version of
457 : : // addUnchecked can be used to have it call CalculateMemPoolAncestors(), and
458 : : // then invoke the second version.
459 : : // Note that addUnchecked is ONLY called from ATMP outside of tests
460 : : // and any other callers may break wallet's in-mempool tracking (due to
461 : : // lack of CValidationInterface::TransactionAddedToMempool callbacks).
462 : : void addUnchecked(const CTxMemPoolEntry& entry) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main);
463 : : void addUnchecked(const CTxMemPoolEntry& entry, setEntries& setAncestors) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main);
464 : :
465 : : void removeRecursive(const CTransaction& tx, MemPoolRemovalReason reason) EXCLUSIVE_LOCKS_REQUIRED(cs);
466 : : /** After reorg, filter the entries that would no longer be valid in the next block, and update
467 : : * the entries' cached LockPoints if needed. The mempool does not have any knowledge of
468 : : * consensus rules. It just applies the callable function and removes the ones for which it
469 : : * returns true.
470 : : * @param[in] filter_final_and_mature Predicate that checks the relevant validation rules
471 : : * and updates an entry's LockPoints.
472 : : * */
473 : : void removeForReorg(CChain& chain, std::function<bool(txiter)> filter_final_and_mature) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main);
474 : : void removeConflicts(const CTransaction& tx) EXCLUSIVE_LOCKS_REQUIRED(cs);
475 : : void removeForBlock(const std::vector<CTransactionRef>& vtx, unsigned int nBlockHeight) EXCLUSIVE_LOCKS_REQUIRED(cs);
476 : :
477 : : bool CompareDepthAndScore(const uint256& hasha, const uint256& hashb, bool wtxid=false);
478 : : bool isSpent(const COutPoint& outpoint) const;
479 : : unsigned int GetTransactionsUpdated() const;
480 : : void AddTransactionsUpdated(unsigned int n);
481 : : /**
482 : : * Check that none of this transactions inputs are in the mempool, and thus
483 : : * the tx is not dependent on other mempool transactions to be included in a block.
484 : : */
485 : : bool HasNoInputsOf(const CTransaction& tx) const EXCLUSIVE_LOCKS_REQUIRED(cs);
486 : :
487 : : /** Affect CreateNewBlock prioritisation of transactions */
488 : : void PrioritiseTransaction(const uint256& hash, const CAmount& nFeeDelta);
489 : : void ApplyDelta(const uint256& hash, CAmount &nFeeDelta) const EXCLUSIVE_LOCKS_REQUIRED(cs);
490 : : void ClearPrioritisation(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs);
491 : :
492 : : struct delta_info {
493 : : /** Whether this transaction is in the mempool. */
494 : : const bool in_mempool;
495 : : /** The fee delta added using PrioritiseTransaction(). */
496 : : const CAmount delta;
497 : : /** The modified fee (base fee + delta) of this entry. Only present if in_mempool=true. */
498 : : std::optional<CAmount> modified_fee;
499 : : /** The prioritised transaction's txid. */
500 : : const uint256 txid;
501 : : };
502 : : /** Return a vector of all entries in mapDeltas with their corresponding delta_info. */
503 : : std::vector<delta_info> GetPrioritisedTransactions() const EXCLUSIVE_LOCKS_REQUIRED(!cs);
504 : :
505 : : /** Get the transaction in the pool that spends the same prevout */
506 : : const CTransaction* GetConflictTx(const COutPoint& prevout) const EXCLUSIVE_LOCKS_REQUIRED(cs);
507 : :
508 : : /** Returns an iterator to the given hash, if found */
509 : : std::optional<txiter> GetIter(const uint256& txid) const EXCLUSIVE_LOCKS_REQUIRED(cs);
510 : :
511 : : /** Translate a set of hashes into a set of pool iterators to avoid repeated lookups.
512 : : * Does not require that all of the hashes correspond to actual transactions in the mempool,
513 : : * only returns the ones that exist. */
514 : : setEntries GetIterSet(const std::set<Txid>& hashes) const EXCLUSIVE_LOCKS_REQUIRED(cs);
515 : :
516 : : /** Translate a list of hashes into a list of mempool iterators to avoid repeated lookups.
517 : : * The nth element in txids becomes the nth element in the returned vector. If any of the txids
518 : : * don't actually exist in the mempool, returns an empty vector. */
519 : : std::vector<txiter> GetIterVec(const std::vector<uint256>& txids) const EXCLUSIVE_LOCKS_REQUIRED(cs);
520 : :
521 : : /** Remove a set of transactions from the mempool.
522 : : * If a transaction is in this set, then all in-mempool descendants must
523 : : * also be in the set, unless this transaction is being removed for being
524 : : * in a block.
525 : : * Set updateDescendants to true when removing a tx that was in a block, so
526 : : * that any in-mempool descendants have their ancestor state updated.
527 : : */
528 : : void RemoveStaged(setEntries& stage, bool updateDescendants, MemPoolRemovalReason reason) EXCLUSIVE_LOCKS_REQUIRED(cs);
529 : :
530 : : /** UpdateTransactionsFromBlock is called when adding transactions from a
531 : : * disconnected block back to the mempool, new mempool entries may have
532 : : * children in the mempool (which is generally not the case when otherwise
533 : : * adding transactions).
534 : : * @post updated descendant state for descendants of each transaction in
535 : : * vHashesToUpdate (excluding any child transactions present in
536 : : * vHashesToUpdate, which are already accounted for). Updated state
537 : : * includes add fee/size information for such descendants to the
538 : : * parent and updated ancestor state to include the parent.
539 : : *
540 : : * @param[in] vHashesToUpdate The set of txids from the
541 : : * disconnected block that have been accepted back into the mempool.
542 : : */
543 : : void UpdateTransactionsFromBlock(const std::vector<uint256>& vHashesToUpdate) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main) LOCKS_EXCLUDED(m_epoch);
544 : :
545 : : /**
546 : : * Try to calculate all in-mempool ancestors of entry.
547 : : * (these are all calculated including the tx itself)
548 : : *
549 : : * @param[in] entry CTxMemPoolEntry of which all in-mempool ancestors are calculated
550 : : * @param[in] limits Maximum number and size of ancestors and descendants
551 : : * @param[in] fSearchForParents Whether to search a tx's vin for in-mempool parents, or look
552 : : * up parents from mapLinks. Must be true for entries not in
553 : : * the mempool
554 : : *
555 : : * @return all in-mempool ancestors, or an error if any ancestor or descendant limits were hit
556 : : */
557 : : util::Result<setEntries> CalculateMemPoolAncestors(const CTxMemPoolEntry& entry,
558 : : const Limits& limits,
559 : : bool fSearchForParents = true) const EXCLUSIVE_LOCKS_REQUIRED(cs);
560 : :
561 : : /**
562 : : * Same as CalculateMemPoolAncestors, but always returns a (non-optional) setEntries.
563 : : * Should only be used when it is assumed CalculateMemPoolAncestors would not fail. If
564 : : * CalculateMemPoolAncestors does unexpectedly fail, an empty setEntries is returned and the
565 : : * error is logged to BCLog::MEMPOOL with level BCLog::Level::Error. In debug builds, failure
566 : : * of CalculateMemPoolAncestors will lead to shutdown due to assertion failure.
567 : : *
568 : : * @param[in] calling_fn_name Name of calling function so we can properly log the call site
569 : : *
570 : : * @return a setEntries corresponding to the result of CalculateMemPoolAncestors or an empty
571 : : * setEntries if it failed
572 : : *
573 : : * @see CTXMemPool::CalculateMemPoolAncestors()
574 : : */
575 : : setEntries AssumeCalculateMemPoolAncestors(
576 : : std::string_view calling_fn_name,
577 : : const CTxMemPoolEntry &entry,
578 : : const Limits& limits,
579 : : bool fSearchForParents = true) const EXCLUSIVE_LOCKS_REQUIRED(cs);
580 : :
581 : : /** Collect the entire cluster of connected transactions for each transaction in txids.
582 : : * All txids must correspond to transaction entries in the mempool, otherwise this returns an
583 : : * empty vector. This call will also exit early and return an empty vector if it collects 500 or
584 : : * more transactions as a DoS protection. */
585 : : std::vector<txiter> GatherClusters(const std::vector<uint256>& txids) const EXCLUSIVE_LOCKS_REQUIRED(cs);
586 : :
587 : : /** Calculate all in-mempool ancestors of a set of transactions not already in the mempool and
588 : : * check ancestor and descendant limits. Heuristics are used to estimate the ancestor and
589 : : * descendant count of all entries if the package were to be added to the mempool. The limits
590 : : * are applied to the union of all package transactions. For example, if the package has 3
591 : : * transactions and limits.ancestor_count = 25, the union of all 3 sets of ancestors (including the
592 : : * transactions themselves) must be <= 22.
593 : : * @param[in] package Transaction package being evaluated for acceptance
594 : : * to mempool. The transactions need not be direct
595 : : * ancestors/descendants of each other.
596 : : * @param[in] total_vsize Sum of virtual sizes for all transactions in package.
597 : : * @returns {} or the error reason if a limit is hit.
598 : : */
599 : : util::Result<void> CheckPackageLimits(const Package& package,
600 : : int64_t total_vsize) const EXCLUSIVE_LOCKS_REQUIRED(cs);
601 : :
602 : : /** Populate setDescendants with all in-mempool descendants of hash.
603 : : * Assumes that setDescendants includes all in-mempool descendants of anything
604 : : * already in it. */
605 : : void CalculateDescendants(txiter it, setEntries& setDescendants) const EXCLUSIVE_LOCKS_REQUIRED(cs);
606 : :
607 : : /** The minimum fee to get into the mempool, which may itself not be enough
608 : : * for larger-sized transactions.
609 : : * The m_incremental_relay_feerate policy variable is used to bound the time it
610 : : * takes the fee rate to go back down all the way to 0. When the feerate
611 : : * would otherwise be half of this, it is set to 0 instead.
612 : : */
613 : 447883 : CFeeRate GetMinFee() const {
614 : 447883 : return GetMinFee(m_opts.max_size_bytes);
615 : : }
616 : :
617 : : /** Remove transactions from the mempool until its dynamic size is <= sizelimit.
618 : : * pvNoSpendsRemaining, if set, will be populated with the list of outpoints
619 : : * which are not in mempool which no longer have any spends in this mempool.
620 : : */
621 : : void TrimToSize(size_t sizelimit, std::vector<COutPoint>* pvNoSpendsRemaining = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs);
622 : :
623 : : /** Expire all transaction (and their dependencies) in the mempool older than time. Return the number of removed transactions. */
624 : : int Expire(std::chrono::seconds time) EXCLUSIVE_LOCKS_REQUIRED(cs);
625 : :
626 : : /**
627 : : * Calculate the ancestor and descendant count for the given transaction.
628 : : * The counts include the transaction itself.
629 : : * When ancestors is non-zero (ie, the transaction itself is in the mempool),
630 : : * ancestorsize and ancestorfees will also be set to the appropriate values.
631 : : */
632 : : void GetTransactionAncestry(const uint256& txid, size_t& ancestors, size_t& descendants, size_t* ancestorsize = nullptr, CAmount* ancestorfees = nullptr) const;
633 : :
634 : : /**
635 : : * @returns true if an initial attempt to load the persisted mempool was made, regardless of
636 : : * whether the attempt was successful or not
637 : : */
638 : : bool GetLoadTried() const;
639 : :
640 : : /**
641 : : * Set whether or not an initial attempt to load the persisted mempool was made (regardless
642 : : * of whether the attempt was successful or not)
643 : : */
644 : : void SetLoadTried(bool load_tried);
645 : :
646 : 4150 : unsigned long size() const
647 : : {
648 : 4150 : LOCK(cs);
649 : 4150 : return mapTx.size();
650 : 4150 : }
651 : :
652 : 43911 : uint64_t GetTotalTxSize() const EXCLUSIVE_LOCKS_REQUIRED(cs)
653 : : {
654 : 43911 : AssertLockHeld(cs);
655 : 43911 : return totalTxSize;
656 : : }
657 : :
658 : 139507 : CAmount GetTotalFee() const EXCLUSIVE_LOCKS_REQUIRED(cs)
659 : : {
660 : 139507 : AssertLockHeld(cs);
661 : 139507 : return m_total_fee;
662 : : }
663 : :
664 : 6533576 : bool exists(const GenTxid& gtxid) const
665 : : {
666 : 6533576 : LOCK(cs);
667 [ + - + + ]: 6533576 : if (gtxid.IsWtxid()) {
668 [ + - + - ]: 540275 : return (mapTx.get<index_by_wtxid>().count(gtxid.GetHash()) != 0);
669 : : }
670 [ + - + - ]: 5993301 : return (mapTx.count(gtxid.GetHash()) != 0);
671 : 6533576 : }
672 : :
673 : : const CTxMemPoolEntry* GetEntry(const Txid& txid) const LIFETIMEBOUND EXCLUSIVE_LOCKS_REQUIRED(cs);
674 : :
675 : : CTransactionRef get(const uint256& hash) const;
676 : 4674 : txiter get_iter_from_wtxid(const uint256& wtxid) const EXCLUSIVE_LOCKS_REQUIRED(cs)
677 : : {
678 : 4674 : AssertLockHeld(cs);
679 : 4674 : return mapTx.project<0>(mapTx.get<index_by_wtxid>().find(wtxid));
680 : : }
681 : : TxMempoolInfo info(const GenTxid& gtxid) const;
682 : :
683 : : /** Returns info for a transaction if its entry_sequence < last_sequence */
684 : : TxMempoolInfo info_for_relay(const GenTxid& gtxid, uint64_t last_sequence) const;
685 : :
686 : : std::vector<CTxMemPoolEntryRef> entryAll() const EXCLUSIVE_LOCKS_REQUIRED(cs);
687 : : std::vector<TxMempoolInfo> infoAll() const;
688 : :
689 : : size_t DynamicMemoryUsage() const;
690 : :
691 : : /** Adds a transaction to the unbroadcast set */
692 : 0 : void AddUnbroadcastTx(const uint256& txid)
693 : : {
694 : 0 : LOCK(cs);
695 : : // Sanity check the transaction is in the mempool & insert into
696 : : // unbroadcast set.
697 [ # # # # : 0 : if (exists(GenTxid::Txid(txid))) m_unbroadcast_txids.insert(txid);
# # # # ]
698 : 0 : };
699 : :
700 : : /** Removes a transaction from the unbroadcast set */
701 : : void RemoveUnbroadcastTx(const uint256& txid, const bool unchecked = false);
702 : :
703 : : /** Returns transactions in unbroadcast set */
704 : 1285 : std::set<uint256> GetUnbroadcastTxs() const
705 : : {
706 : 1285 : LOCK(cs);
707 [ + - ]: 1285 : return m_unbroadcast_txids;
708 : 1285 : }
709 : :
710 : : /** Returns whether a txid is in the unbroadcast set */
711 : 0 : bool IsUnbroadcastTx(const uint256& txid) const EXCLUSIVE_LOCKS_REQUIRED(cs)
712 : : {
713 : 0 : AssertLockHeld(cs);
714 : 0 : return m_unbroadcast_txids.count(txid) != 0;
715 : : }
716 : :
717 : : /** Guards this internal counter for external reporting */
718 : 109845 : uint64_t GetAndIncrementSequence() const EXCLUSIVE_LOCKS_REQUIRED(cs) {
719 : 109845 : return m_sequence_number++;
720 : : }
721 : :
722 : 149724 : uint64_t GetSequence() const EXCLUSIVE_LOCKS_REQUIRED(cs) {
723 : 149724 : return m_sequence_number;
724 : : }
725 : :
726 : : /**
727 : : * Calculate the sorted chunks for the old and new mempool relating to the
728 : : * clusters that would be affected by a potential replacement transaction.
729 : : * (replacement_fees, replacement_vsize) values are gathered from a
730 : : * proposed set of replacement transactions that are considered as a single
731 : : * chunk, and represent their complete cluster. In other words, they have no
732 : : * in-mempool ancestors.
733 : : *
734 : : * @param[in] replacement_fees Package fees
735 : : * @param[in] replacement_vsize Package size (must be greater than 0)
736 : : * @param[in] direct_conflicts All transactions that would be removed directly by
737 : : * having a conflicting input with a proposed transaction
738 : : * @param[in] all_conflicts All transactions that would be removed
739 : : * @return old and new diagram pair respectively, or an error string if the conflicts don't match a calculable topology
740 : : */
741 : : 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);
742 : :
743 : : /* Check that all direct conflicts are in a cluster size of two or less. Each
744 : : * direct conflict may be in a separate cluster.
745 : : */
746 : : std::optional<std::string> CheckConflictTopology(const setEntries& direct_conflicts);
747 : :
748 : : private:
749 : : /** UpdateForDescendants is used by UpdateTransactionsFromBlock to update
750 : : * the descendants for a single transaction that has been added to the
751 : : * mempool but may have child transactions in the mempool, eg during a
752 : : * chain reorg.
753 : : *
754 : : * @pre CTxMemPoolEntry::m_children is correct for the given tx and all
755 : : * descendants.
756 : : * @pre cachedDescendants is an accurate cache where each entry has all
757 : : * descendants of the corresponding key, including those that should
758 : : * be removed for violation of ancestor limits.
759 : : * @post if updateIt has any non-excluded descendants, cachedDescendants has
760 : : * a new cache line for updateIt.
761 : : * @post descendants_to_remove has a new entry for any descendant which exceeded
762 : : * ancestor limits relative to updateIt.
763 : : *
764 : : * @param[in] updateIt the entry to update for its descendants
765 : : * @param[in,out] cachedDescendants a cache where each line corresponds to all
766 : : * descendants. It will be updated with the descendants of the transaction
767 : : * being updated, so that future invocations don't need to walk the same
768 : : * transaction again, if encountered in another transaction chain.
769 : : * @param[in] setExclude the set of descendant transactions in the mempool
770 : : * that must not be accounted for (because any descendants in setExclude
771 : : * were added to the mempool after the transaction being updated and hence
772 : : * their state is already reflected in the parent state).
773 : : * @param[out] descendants_to_remove Populated with the txids of entries that
774 : : * exceed ancestor limits. It's the responsibility of the caller to
775 : : * removeRecursive them.
776 : : */
777 : : void UpdateForDescendants(txiter updateIt, cacheMap& cachedDescendants,
778 : : const std::set<uint256>& setExclude, std::set<uint256>& descendants_to_remove) EXCLUSIVE_LOCKS_REQUIRED(cs);
779 : : /** Update ancestors of hash to add/remove it as a descendant transaction. */
780 : : void UpdateAncestorsOf(bool add, txiter hash, setEntries &setAncestors) EXCLUSIVE_LOCKS_REQUIRED(cs);
781 : : /** Set ancestor state for an entry */
782 : : void UpdateEntryForAncestors(txiter it, const setEntries &setAncestors) EXCLUSIVE_LOCKS_REQUIRED(cs);
783 : : /** For each transaction being removed, update ancestors and any direct children.
784 : : * If updateDescendants is true, then also update in-mempool descendants'
785 : : * ancestor state. */
786 : : void UpdateForRemoveFromMempool(const setEntries &entriesToRemove, bool updateDescendants) EXCLUSIVE_LOCKS_REQUIRED(cs);
787 : : /** Sever link between specified transaction and direct children. */
788 : : void UpdateChildrenForRemoval(txiter entry) EXCLUSIVE_LOCKS_REQUIRED(cs);
789 : :
790 : : /** Before calling removeUnchecked for a given transaction,
791 : : * UpdateForRemoveFromMempool must be called on the entire (dependent) set
792 : : * of transactions being removed at the same time. We use each
793 : : * CTxMemPoolEntry's setMemPoolParents in order to walk ancestors of a
794 : : * given transaction that is removed, so we can't remove intermediate
795 : : * transactions in a chain before we've updated all the state for the
796 : : * removal.
797 : : */
798 : : void removeUnchecked(txiter entry, MemPoolRemovalReason reason) EXCLUSIVE_LOCKS_REQUIRED(cs);
799 : : public:
800 : : /** visited marks a CTxMemPoolEntry as having been traversed
801 : : * during the lifetime of the most recently created Epoch::Guard
802 : : * and returns false if we are the first visitor, true otherwise.
803 : : *
804 : : * An Epoch::Guard must be held when visited is called or an assert will be
805 : : * triggered.
806 : : *
807 : : */
808 : 842706 : bool visited(const txiter it) const EXCLUSIVE_LOCKS_REQUIRED(cs, m_epoch)
809 : : {
810 : 842706 : return m_epoch.visited(it->m_epoch_marker);
811 : : }
812 : :
813 : : bool visited(std::optional<txiter> it) const EXCLUSIVE_LOCKS_REQUIRED(cs, m_epoch)
814 : : {
815 : : assert(m_epoch.guarded()); // verify guard even when it==nullopt
816 : : return !it || visited(*it);
817 : : }
818 : : };
819 : :
820 : : /**
821 : : * CCoinsView that brings transactions from a mempool into view.
822 : : * It does not check for spendings by memory pool transactions.
823 : : * Instead, it provides access to all Coins which are either unspent in the
824 : : * base CCoinsView, are outputs from any mempool transaction, or are
825 : : * tracked temporarily to allow transaction dependencies in package validation.
826 : : * This allows transaction replacement to work as expected, as you want to
827 : : * have all inputs "available" to check signatures, and any cycles in the
828 : : * dependency graph are checked directly in AcceptToMemoryPool.
829 : : * It also allows you to sign a double-spend directly in
830 : : * signrawtransactionwithkey and signrawtransactionwithwallet,
831 : : * as long as the conflicting transaction is not yet confirmed.
832 : : */
833 : : class CCoinsViewMemPool : public CCoinsViewBacked
834 : : {
835 : : /**
836 : : * Coins made available by transactions being validated. Tracking these allows for package
837 : : * validation, since we can access transaction outputs without submitting them to mempool.
838 : : */
839 : : std::unordered_map<COutPoint, Coin, SaltedOutpointHasher> m_temp_added;
840 : :
841 : : /**
842 : : * Set of all coins that have been fetched from mempool or created using PackageAddTransaction
843 : : * (not base). Used to track the origin of a coin, see GetNonBaseCoins().
844 : : */
845 : : mutable std::unordered_set<COutPoint, SaltedOutpointHasher> m_non_base_coins;
846 : : protected:
847 : : const CTxMemPool& mempool;
848 : :
849 : : public:
850 : : CCoinsViewMemPool(CCoinsView* baseIn, const CTxMemPool& mempoolIn);
851 : : /** GetCoin, returning whether it exists and is not spent. Also updates m_non_base_coins if the
852 : : * coin is not fetched from base. */
853 : : bool GetCoin(const COutPoint &outpoint, Coin &coin) const override;
854 : : /** Add the coins created by this transaction. These coins are only temporarily stored in
855 : : * m_temp_added and cannot be flushed to the back end. Only used for package validation. */
856 : : void PackageAddTransaction(const CTransactionRef& tx);
857 : : /** Get all coins in m_non_base_coins. */
858 : 15966 : std::unordered_set<COutPoint, SaltedOutpointHasher> GetNonBaseCoins() const { return m_non_base_coins; }
859 : : /** Clear m_temp_added and m_non_base_coins. */
860 : : void Reset();
861 : : };
862 : : #endif // BITCOIN_TXMEMPOOL_H
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