1 // Copyright (c) 2009-2010 Satoshi Nakamoto
2 // Copyright (c) 2009-2022 The Limenka 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 LIMENKA_TXMEMPOOL_H
7 #define LIMENKA_TXMEMPOOL_H
8 9 #include <coins.h>
10 #include <consensus/amount.h>
11 #include <consensus/params.h>
12 #include <indirectmap.h>
13 #include <kernel/cs_main.h>
14 #include <kernel/mempool_entry.h> // IWYU pragma: export
15 #include <kernel/mempool_limits.h> // IWYU pragma: export
16 #include <kernel/mempool_options.h> // IWYU pragma: export
17 #include <kernel/mempool_removal_reason.h> // IWYU pragma: export
18 #include <policy/feerate.h>
19 #include <policy/packages.h>
20 #include <primitives/transaction.h>
21 #include <script/script.h>
22 #include <sync.h>
23 #include <util/epochguard.h>
24 #include <util/hasher.h>
25 #include <util/result.h>
26 #include <util/feefrac.h>
27 28 #include <boost/multi_index/hashed_index.hpp>
29 #include <boost/multi_index/identity.hpp>
30 #include <boost/multi_index/indexed_by.hpp>
31 #include <boost/multi_index/ordered_index.hpp>
32 #include <boost/multi_index/sequenced_index.hpp>
33 #include <boost/multi_index/tag.hpp>
34 #include <boost/multi_index_container.hpp>
35 36 #include <atomic>
37 #include <map>
38 #include <optional>
39 #include <set>
40 #include <string>
41 #include <string_view>
42 #include <utility>
43 #include <vector>
44 45 class CChain;
46 class CScript;
47 class ValidationSignals;
48 49 struct bilingual_str;
50 51 static constexpr std::chrono::minutes DYNAMIC_DUST_FEERATE_UPDATE_INTERVAL{15};
52 53 /** Fake height value used in Coin to signify they are only in the memory pool (since 0.8) */
54 static const uint32_t MEMPOOL_HEIGHT = 0x7FFFFFFF;
55 56 inline int64_t maxmempoolMinimumBytes(const int64_t descendant_size_vbytes) {
57 return descendant_size_vbytes * 40;
58 }
59 inline int64_t limitdescendantsizeMaximumVBytes(const int64_t maxmempool) {
60 return maxmempool / 40;
61 }
62 63 /**
64 * Test whether the LockPoints height and time are still valid on the current chain
65 */
66 bool TestLockPointValidity(CChain& active_chain, const LockPoints& lp) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
67 68 // extracts a transaction hash from CTxMemPoolEntry or CTransactionRef
69 struct mempoolentry_txid
70 {
71 typedef uint256 result_type;
72 result_type operator() (const CTxMemPoolEntry &entry) const
73 {
74 return entry.GetTx().GetHash();
75 }
76 77 result_type operator() (const CTransactionRef& tx) const
78 {
79 return tx->GetHash();
80 }
81 };
82 83 // extracts a transaction witness-hash from CTxMemPoolEntry or CTransactionRef
84 struct mempoolentry_wtxid
85 {
86 typedef uint256 result_type;
87 result_type operator() (const CTxMemPoolEntry &entry) const
88 {
89 return entry.GetTx().GetWitnessHash();
90 }
91 92 result_type operator() (const CTransactionRef& tx) const
93 {
94 return tx->GetWitnessHash();
95 }
96 };
97 98 99 /** \class CompareTxMemPoolEntryByDescendantScore
100 *
101 * Sort an entry by max(score/size of entry's tx, score/size with all descendants).
102 */
103 class CompareTxMemPoolEntryByDescendantScore
104 {
105 public:
106 bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const
107 {
108 double a_mod_fee, a_size, b_mod_fee, b_size;
109 110 GetModFeeAndSize(a, a_mod_fee, a_size);
111 GetModFeeAndSize(b, b_mod_fee, b_size);
112 113 // Avoid division by rewriting (a/b > c/d) as (a*d > c*b).
114 double f1 = a_mod_fee * b_size;
115 double f2 = a_size * b_mod_fee;
116 117 if (f1 == f2) {
118 return a.GetTime() >= b.GetTime();
119 }
120 return f1 < f2;
121 }
122 123 // Return the fee/size we're using for sorting this entry.
124 void GetModFeeAndSize(const CTxMemPoolEntry &a, double &mod_fee, double &size) const
125 {
126 // Compare feerate with descendants to feerate of the transaction, and
127 // return the fee/size for the max.
128 double f1 = (double)a.GetModifiedFee() * a.GetSizeWithDescendants();
129 double f2 = (double)a.GetModFeesWithDescendants() * a.GetTxSize();
130 131 if (f2 > f1) {
132 mod_fee = a.GetModFeesWithDescendants();
133 size = a.GetSizeWithDescendants();
134 } else {
135 mod_fee = a.GetModifiedFee();
136 size = a.GetTxSize();
137 }
138 }
139 };
140 141 /** \class CompareTxMemPoolEntryByScore
142 *
143 * Sort by feerate of entry (fee/size) in descending order
144 * This is only used for transaction relay, so we use GetFee()
145 * instead of GetModifiedFee() to avoid leaking prioritization
146 * information via the sort order.
147 */
148 class CompareTxMemPoolEntryByScore
149 {
150 public:
151 bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const
152 {
153 double f1 = (double)a.GetFee() * b.GetTxSize();
154 double f2 = (double)b.GetFee() * a.GetTxSize();
155 if (f1 == f2) {
156 return b.GetTx().GetHash() < a.GetTx().GetHash();
157 }
158 return f1 > f2;
159 }
160 };
161 162 class CompareTxMemPoolEntryByEntryTime
163 {
164 public:
165 bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const
166 {
167 return a.GetTime() < b.GetTime();
168 }
169 };
170 171 /** \class CompareTxMemPoolEntryByAncestorScore
172 *
173 * Sort an entry by min(score/size of entry's tx, score/size with all ancestors).
174 */
175 class CompareTxMemPoolEntryByAncestorFee
176 {
177 public:
178 template<typename T>
179 bool operator()(const T& a, const T& b) const
180 {
181 double a_mod_fee, a_size, b_mod_fee, b_size;
182 183 GetModFeeAndSize(a, a_mod_fee, a_size);
184 GetModFeeAndSize(b, b_mod_fee, b_size);
185 186 // Avoid division by rewriting (a/b > c/d) as (a*d > c*b).
187 double f1 = a_mod_fee * b_size;
188 double f2 = a_size * b_mod_fee;
189 190 if (f1 == f2) {
191 return a.GetTx().GetHash() < b.GetTx().GetHash();
192 }
193 return f1 > f2;
194 }
195 196 // Return the fee/size we're using for sorting this entry.
197 template <typename T>
198 void GetModFeeAndSize(const T &a, double &mod_fee, double &size) const
199 {
200 // Compare feerate with ancestors to feerate of the transaction, and
201 // return the fee/size for the min.
202 double f1 = (double)a.GetModifiedFee() * a.GetSizeWithAncestors();
203 double f2 = (double)a.GetModFeesWithAncestors() * a.GetTxSize();
204 205 if (f1 > f2) {
206 mod_fee = a.GetModFeesWithAncestors();
207 size = a.GetSizeWithAncestors();
208 } else {
209 mod_fee = a.GetModifiedFee();
210 size = a.GetTxSize();
211 }
212 }
213 };
214 215 uint160 ScriptHashkey(const CScript& script);
216 217 // Multi_index tag names
218 struct descendant_score {};
219 struct entry_time {};
220 struct ancestor_score {};
221 struct index_by_wtxid {};
222 223 class CBlockPolicyEstimator;
224 225 /**
226 * Information about a mempool transaction.
227 */
228 struct TxMempoolInfo
229 {
230 /** The transaction itself */
231 CTransactionRef tx;
232 233 /** Time the transaction entered the mempool. */
234 std::chrono::seconds m_time;
235 236 /** Fee of the transaction. */
237 CAmount fee;
238 239 /** Virtual size of the transaction. */
240 int32_t vsize;
241 242 /** The fee delta. */
243 int64_t nFeeDelta;
244 };
245 246 /**
247 * CTxMemPool stores valid-according-to-the-current-best-chain transactions
248 * that may be included in the next block.
249 *
250 * Transactions are added when they are seen on the network (or created by the
251 * local node), but not all transactions seen are added to the pool. For
252 * example, the following new transactions will not be added to the mempool:
253 * - a transaction which doesn't meet the minimum fee requirements.
254 * - a new transaction that double-spends an input of a transaction already in
255 * the pool where the new transaction does not meet the Replace-By-Fee
256 * requirements as defined in doc/policy/mempool-replacements.md.
257 * - a non-standard transaction.
258 *
259 * CTxMemPool::mapTx, and CTxMemPoolEntry bookkeeping:
260 *
261 * mapTx is a boost::multi_index that sorts the mempool on 5 criteria:
262 * - transaction hash (txid)
263 * - witness-transaction hash (wtxid)
264 * - descendant feerate [we use max(feerate of tx, feerate of tx with all descendants)]
265 * - time in mempool
266 * - ancestor feerate [we use min(feerate of tx, feerate of tx with all unconfirmed ancestors)]
267 *
268 * Note: the term "descendant" refers to in-mempool transactions that depend on
269 * this one, while "ancestor" refers to in-mempool transactions that a given
270 * transaction depends on.
271 *
272 * In order for the feerate sort to remain correct, we must update transactions
273 * in the mempool when new descendants arrive. To facilitate this, we track
274 * the set of in-mempool direct parents and direct children in mapLinks. Within
275 * each CTxMemPoolEntry, we track the size and fees of all descendants.
276 *
277 * Usually when a new transaction is added to the mempool, it has no in-mempool
278 * children (because any such children would be an orphan). So in
279 * addNewTransaction(), we:
280 * - update a new entry's m_parents to include all in-mempool parents
281 * - update each of those parent entries to include the new tx as a child
282 * - update all ancestors of the transaction to include the new tx's size/fee
283 *
284 * When a transaction is removed from the mempool, we must:
285 * - update all in-mempool parents to not track the tx in their m_children
286 * - update all ancestors to not include the tx's size/fees in descendant state
287 * - update all in-mempool children to not include it as a parent
288 *
289 * These happen in UpdateForRemoveFromMempool(). (Note that when removing a
290 * transaction along with its descendants, we must calculate that set of
291 * transactions to be removed before doing the removal, or else the mempool can
292 * be in an inconsistent state where it's impossible to walk the ancestors of
293 * a transaction.)
294 *
295 * In the event of a reorg, the assumption that a newly added tx has no
296 * in-mempool children is false. In particular, the mempool is in an
297 * inconsistent state while new transactions are being added, because there may
298 * be descendant transactions of a tx coming from a disconnected block that are
299 * unreachable from just looking at transactions in the mempool (the linking
300 * transactions may also be in the disconnected block, waiting to be added).
301 * Because of this, there's not much benefit in trying to search for in-mempool
302 * children in addNewTransaction(). Instead, in the special case of transactions
303 * being added from a disconnected block, we require the caller to clean up the
304 * state, to account for in-mempool, out-of-block descendants for all the
305 * in-block transactions by calling UpdateTransactionsFromBlock(). Note that
306 * until this is called, the mempool state is not consistent, and in particular
307 * mapLinks may not be correct (and therefore functions like
308 * CalculateMemPoolAncestors() and CalculateDescendants() that rely
309 * on them to walk the mempool are not generally safe to use).
310 *
311 * Computational limits:
312 *
313 * Updating all in-mempool ancestors of a newly added transaction can be slow,
314 * if no bound exists on how many in-mempool ancestors there may be.
315 * CalculateMemPoolAncestors() takes configurable limits that are designed to
316 * prevent these calculations from being too CPU intensive.
317 *
318 */
319 class CTxMemPool
320 {
321 protected:
322 std::atomic<unsigned int> nTransactionsUpdated{0}; //!< Used by getblocktemplate to trigger CreateNewBlock() invocation
323 324 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.
325 CAmount m_total_fee GUARDED_BY(cs){0}; //!< sum of all mempool tx's fees (NOT modified fee)
326 uint64_t cachedInnerUsage GUARDED_BY(cs){0}; //!< sum of dynamic memory usage of all the map elements (NOT the maps themselves)
327 328 mutable int64_t lastRollingFeeUpdate GUARDED_BY(cs){GetTime()};
329 mutable bool blockSinceLastRollingFeeBump GUARDED_BY(cs){false};
330 mutable double rollingMinimumFeeRate GUARDED_BY(cs){0}; //!< minimum fee to get into the pool, decreases exponentially
331 mutable Epoch m_epoch GUARDED_BY(cs){};
332 333 // In-memory counter for external mempool tracking purposes.
334 // This number is incremented once every time a transaction
335 // is added or removed from the mempool for any reason.
336 mutable uint64_t m_sequence_number GUARDED_BY(cs){1};
337 338 void trackPackageRemoved(const CFeeRate& rate) EXCLUSIVE_LOCKS_REQUIRED(cs);
339 340 bool m_load_tried GUARDED_BY(cs){false};
341 342 CFeeRate GetMinFee(size_t sizelimit) const;
343 344 public:
345 346 static const int ROLLING_FEE_HALFLIFE = 60 * 60 * 12; // public only for testing
347 348 using CTxMemPoolEntry_Indices_ = boost::multi_index::indexed_by<
349 // sorted by txid
350 boost::multi_index::hashed_unique<mempoolentry_txid, SaltedTxidHasher>,
351 // sorted by wtxid
352 boost::multi_index::hashed_unique<
353 boost::multi_index::tag<index_by_wtxid>,
354 mempoolentry_wtxid,
355 SaltedTxidHasher
356 >,
357 // sorted by fee rate
358 boost::multi_index::ordered_non_unique<
359 boost::multi_index::tag<descendant_score>,
360 boost::multi_index::identity<CTxMemPoolEntry>,
361 CompareTxMemPoolEntryByDescendantScore
362 >,
363 // sorted by entry time
364 boost::multi_index::ordered_non_unique<
365 boost::multi_index::tag<entry_time>,
366 boost::multi_index::identity<CTxMemPoolEntry>,
367 CompareTxMemPoolEntryByEntryTime
368 >,
369 // sorted by fee rate with ancestors
370 boost::multi_index::ordered_non_unique<
371 boost::multi_index::tag<ancestor_score>,
372 boost::multi_index::identity<CTxMemPoolEntry>,
373 CompareTxMemPoolEntryByAncestorFee
374 >
375 >;
376 #if BOOST_VERSION >= 109100
377 using CTxMemPoolEntry_Indices = CTxMemPoolEntry_Indices_;
378 #else
379 struct CTxMemPoolEntry_Indices final : CTxMemPoolEntry_Indices_{};
380 #endif
381 typedef boost::multi_index_container<
382 CTxMemPoolEntry,
383 CTxMemPoolEntry_Indices
384 > indexed_transaction_set;
385 386 /**
387 * This mutex needs to be locked when accessing `mapTx` or other members
388 * that are guarded by it.
389 *
390 * @par Consistency guarantees
391 * By design, it is guaranteed that:
392 * 1. Locking both `cs_main` and `mempool.cs` will give a view of mempool
393 * that is consistent with current chain tip (`ActiveChain()` and
394 * `CoinsTip()`) and is fully populated. Fully populated means that if the
395 * current active chain is missing transactions that were present in a
396 * previously active chain, all the missing transactions will have been
397 * re-added to the mempool and should be present if they meet size and
398 * consistency constraints.
399 * 2. Locking `mempool.cs` without `cs_main` will give a view of a mempool
400 * consistent with some chain that was active since `cs_main` was last
401 * locked, and that is fully populated as described above. It is ok for
402 * code that only needs to query or remove transactions from the mempool
403 * to lock just `mempool.cs` without `cs_main`.
404 *
405 * To provide these guarantees, it is necessary to lock both `cs_main` and
406 * `mempool.cs` whenever adding transactions to the mempool and whenever
407 * changing the chain tip. It's necessary to keep both mutexes locked until
408 * the mempool is consistent with the new chain tip and fully populated.
409 */
410 mutable RecursiveMutex cs;
411 indexed_transaction_set mapTx GUARDED_BY(cs);
412 413 using txiter = indexed_transaction_set::nth_index<0>::type::const_iterator;
414 std::vector<CTransactionRef> txns_randomized GUARDED_BY(cs); //!< All transactions in mapTx, in random order
415 416 typedef std::set<txiter, CompareIteratorByHash> setEntries;
417 418 using Limits = kernel::MemPoolLimits;
419 420 uint64_t CalculateDescendantMaximum(txiter entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
421 422 std::map<uint160, std::pair<const CTransaction *, const CTransaction *>> mapUsedSPK;
423 424 private:
425 typedef std::map<txiter, setEntries, CompareIteratorByHash> cacheMap;
426 427 428 void UpdateParent(txiter entry, txiter parent, bool add) EXCLUSIVE_LOCKS_REQUIRED(cs);
429 void UpdateChild(txiter entry, txiter child, bool add) EXCLUSIVE_LOCKS_REQUIRED(cs);
430 431 std::vector<indexed_transaction_set::const_iterator> GetSortedDepthAndScore() const EXCLUSIVE_LOCKS_REQUIRED(cs);
432 433 /**
434 * Track locally submitted transactions to periodically retry initial broadcast.
435 */
436 std::set<uint256> m_unbroadcast_txids GUARDED_BY(cs);
437 438 439 /**
440 * Helper function to calculate all in-mempool ancestors of staged_ancestors and apply ancestor
441 * and descendant limits (including staged_ancestors themselves, entry_size and entry_count).
442 *
443 * @param[in] entry_size Virtual size to include in the limits.
444 * @param[in] entry_count How many entries to include in the limits.
445 * @param[in] staged_ancestors Should contain entries in the mempool.
446 * @param[in] limits Maximum number and size of ancestors and descendants
447 *
448 * @return all in-mempool ancestors, or an error if any ancestor or descendant limits were hit
449 */
450 util::Result<setEntries> CalculateAncestorsAndCheckLimits(int64_t entry_size,
451 size_t entry_count,
452 CTxMemPoolEntry::Parents &staged_ancestors,
453 const Limits& limits
454 ) const EXCLUSIVE_LOCKS_REQUIRED(cs);
455 456 public:
457 indirectmap<COutPoint, const CTransaction*> mapNextTx GUARDED_BY(cs);
458 std::map<uint256, std::pair<double, CAmount> > mapDeltas GUARDED_BY(cs);
459 460 using Options = kernel::MemPoolOptions;
461 462 Options m_opts;
463 464 /** Create a new CTxMemPool.
465 * Sanity checks will be off by default for performance, because otherwise
466 * accepting transactions becomes O(N^2) where N is the number of transactions
467 * in the pool.
468 */
469 explicit CTxMemPool(Options opts, bilingual_str& error);
470 471 /**
472 * If sanity-checking is turned on, check makes sure the pool is
473 * consistent (does not contain two transactions that spend the same inputs,
474 * all inputs are in the mapNextTx array). If sanity-checking is turned off,
475 * check does nothing.
476 */
477 void check(const CCoinsViewCache& active_coins_tip, int64_t spendheight, const Consensus::Params& consensusParams, bool fork_active = false) const EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
478 479 480 void removeRecursive(const CTransaction& tx, MemPoolRemovalReason reason) EXCLUSIVE_LOCKS_REQUIRED(cs);
481 /** After reorg, filter the entries that would no longer be valid in the next block, and update
482 * the entries' cached LockPoints if needed. The mempool does not have any knowledge of
483 * consensus rules. It just applies the callable function and removes the ones for which it
484 * returns true.
485 * @param[in] filter_final_and_mature Predicate that checks the relevant validation rules
486 * and updates an entry's LockPoints.
487 * */
488 void removeForReorg(CChain& chain, std::function<bool(txiter)> filter_final_and_mature) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main);
489 void removeConflicts(const CTransaction& tx) EXCLUSIVE_LOCKS_REQUIRED(cs);
490 void removeForBlock(const std::vector<CTransactionRef>& vtx, unsigned int nBlockHeight) EXCLUSIVE_LOCKS_REQUIRED(cs);
491 492 bool CompareDepthAndScore(const uint256& hasha, const uint256& hashb, bool wtxid=false);
493 bool isSpent(const COutPoint& outpoint) const;
494 unsigned int GetTransactionsUpdated() const;
495 void AddTransactionsUpdated(unsigned int n);
496 /**
497 * Check that none of this transactions inputs are in the mempool, and thus
498 * the tx is not dependent on other mempool transactions to be included in a block.
499 */
500 bool HasNoInputsOf(const CTransaction& tx) const EXCLUSIVE_LOCKS_REQUIRED(cs);
501 /**
502 * Update all transactions in the mempool which depend on tx to recalculate their priority
503 * and adjust the input value that will age to reflect that the inputs from this transaction have
504 * either just been added to the chain or just been removed.
505 */
506 void UpdateDependentPriorities(const CTransaction &tx, unsigned int nBlockHeight, bool addToChain);
507 508 void UpdateDynamicDustFeerate();
509 510 /** Affect CreateNewBlock prioritisation of transactions */
511 void PrioritiseTransaction(const uint256& hash, double dPriorityDelta, const CAmount& nFeeDelta);
512 void PrioritiseTransaction(const uint256& hash, const CAmount& nFeeDelta) { PrioritiseTransaction(hash, 0., nFeeDelta); }
513 void ApplyDeltas(const uint256& hash, double &dPriorityDelta, CAmount &nFeeDelta) const EXCLUSIVE_LOCKS_REQUIRED(cs);
514 void ClearPrioritisation(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs);
515 516 struct delta_info {
517 /** Whether this transaction is in the mempool. */
518 const bool in_mempool;
519 /** The fee delta added using PrioritiseTransaction(). */
520 const CAmount delta;
521 const double priority_delta;
522 /** The modified fee (base fee + delta) of this entry. Only present if in_mempool=true. */
523 std::optional<CAmount> modified_fee;
524 /** The prioritised transaction's txid. */
525 const uint256 txid;
526 };
527 /** Return a vector of all entries in mapDeltas with their corresponding delta_info. */
528 std::vector<delta_info> GetPrioritisedTransactions() const EXCLUSIVE_LOCKS_REQUIRED(!cs);
529 530 /** Get the transaction in the pool that spends the same prevout */
531 const CTransaction* GetConflictTx(const COutPoint& prevout) const EXCLUSIVE_LOCKS_REQUIRED(cs);
532 533 /** Returns an iterator to the given hash, if found */
534 std::optional<txiter> GetIter(const uint256& txid) const EXCLUSIVE_LOCKS_REQUIRED(cs);
535 536 /** Translate a set of hashes into a set of pool iterators to avoid repeated lookups.
537 * Does not require that all of the hashes correspond to actual transactions in the mempool,
538 * only returns the ones that exist. */
539 setEntries GetIterSet(const std::set<Txid>& hashes) const EXCLUSIVE_LOCKS_REQUIRED(cs);
540 541 /** Translate a list of hashes into a list of mempool iterators to avoid repeated lookups.
542 * The nth element in txids becomes the nth element in the returned vector. If any of the txids
543 * don't actually exist in the mempool, returns an empty vector. */
544 std::vector<txiter> GetIterVec(const std::vector<uint256>& txids) const EXCLUSIVE_LOCKS_REQUIRED(cs);
545 546 /** UpdateTransactionsFromBlock is called when adding transactions from a
547 * disconnected block back to the mempool, new mempool entries may have
548 * children in the mempool (which is generally not the case when otherwise
549 * adding transactions).
550 * @post updated descendant state for descendants of each transaction in
551 * vHashesToUpdate (excluding any child transactions present in
552 * vHashesToUpdate, which are already accounted for). Updated state
553 * includes add fee/size information for such descendants to the
554 * parent and updated ancestor state to include the parent.
555 *
556 * @param[in] vHashesToUpdate The set of txids from the
557 * disconnected block that have been accepted back into the mempool.
558 */
559 void UpdateTransactionsFromBlock(const std::vector<uint256>& vHashesToUpdate) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main) LOCKS_EXCLUDED(m_epoch);
560 561 /**
562 * Try to calculate all in-mempool ancestors of entry.
563 * (these are all calculated including the tx itself)
564 *
565 * @param[in] entry CTxMemPoolEntry of which all in-mempool ancestors are calculated
566 * @param[in] limits Maximum number and size of ancestors and descendants
567 * @param[in] fSearchForParents Whether to search a tx's vin for in-mempool parents, or look
568 * up parents from mapLinks. Must be true for entries not in
569 * the mempool
570 *
571 * @return all in-mempool ancestors, or an error if any ancestor or descendant limits were hit
572 */
573 util::Result<setEntries> CalculateMemPoolAncestors(const CTxMemPoolEntry& entry,
574 const Limits& limits,
575 bool fSearchForParents = true) const EXCLUSIVE_LOCKS_REQUIRED(cs);
576 577 /**
578 * Same as CalculateMemPoolAncestors, but always returns a (non-optional) setEntries.
579 * Should only be used when it is assumed CalculateMemPoolAncestors would not fail. If
580 * CalculateMemPoolAncestors does unexpectedly fail, an empty setEntries is returned and the
581 * error is logged to BCLog::MEMPOOL with level BCLog::Level::Error. In debug builds, failure
582 * of CalculateMemPoolAncestors will lead to shutdown due to assertion failure.
583 *
584 * @param[in] calling_fn_name Name of calling function so we can properly log the call site
585 *
586 * @return a setEntries corresponding to the result of CalculateMemPoolAncestors or an empty
587 * setEntries if it failed
588 *
589 * @see CTXMemPool::CalculateMemPoolAncestors()
590 */
591 setEntries AssumeCalculateMemPoolAncestors(
592 std::string_view calling_fn_name,
593 const CTxMemPoolEntry &entry,
594 const Limits& limits,
595 bool fSearchForParents = true) const EXCLUSIVE_LOCKS_REQUIRED(cs);
596 597 /** Collect the entire cluster of connected transactions for each transaction in txids.
598 * All txids must correspond to transaction entries in the mempool, otherwise this returns an
599 * empty vector. This call will also exit early and return an empty vector if it collects 500 or
600 * more transactions as a DoS protection. */
601 std::vector<txiter> GatherClusters(const std::vector<uint256>& txids) const EXCLUSIVE_LOCKS_REQUIRED(cs);
602 603 /** Calculate all in-mempool ancestors of a set of transactions not already in the mempool and
604 * check ancestor and descendant limits. Heuristics are used to estimate the ancestor and
605 * descendant count of all entries if the package were to be added to the mempool. The limits
606 * are applied to the union of all package transactions. For example, if the package has 3
607 * transactions and limits.ancestor_count = 25, the union of all 3 sets of ancestors (including the
608 * transactions themselves) must be <= 22.
609 * @param[in] package Transaction package being evaluated for acceptance
610 * to mempool. The transactions need not be direct
611 * ancestors/descendants of each other.
612 * @param[in] total_vsize Sum of virtual sizes for all transactions in package.
613 * @returns {} or the error reason if a limit is hit.
614 */
615 util::Result<void> CheckPackageLimits(const Package& package,
616 int64_t total_vsize) const EXCLUSIVE_LOCKS_REQUIRED(cs);
617 618 /** Populate setDescendants with all in-mempool descendants of hash.
619 * Assumes that setDescendants includes all in-mempool descendants of anything
620 * already in it. */
621 void CalculateDescendants(txiter it, setEntries& setDescendants) const EXCLUSIVE_LOCKS_REQUIRED(cs);
622 623 /** The minimum fee to get into the mempool, which may itself not be enough
624 * for larger-sized transactions.
625 * The m_incremental_relay_feerate policy variable is used to bound the time it
626 * takes the fee rate to go back down all the way to 0. When the feerate
627 * would otherwise be half of this, it is set to 0 instead.
628 */
629 CFeeRate GetMinFee() const {
630 return GetMinFee(m_opts.max_size_bytes);
631 }
632 633 /** Remove transactions from the mempool until its dynamic size is <= sizelimit.
634 * pvNoSpendsRemaining, if set, will be populated with the list of outpoints
635 * which are not in mempool which no longer have any spends in this mempool.
636 */
637 void TrimToSize(size_t sizelimit, std::vector<COutPoint>* pvNoSpendsRemaining = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs);
638 639 /** Expire all transaction (and their dependencies) in the mempool older than time. Return the number of removed transactions. */
640 int Expire(std::chrono::seconds time) EXCLUSIVE_LOCKS_REQUIRED(cs);
641 642 /**
643 * Calculate the ancestor and descendant count for the given transaction.
644 * The counts include the transaction itself.
645 * When ancestors is non-zero (ie, the transaction itself is in the mempool),
646 * ancestorsize and ancestorfees will also be set to the appropriate values.
647 */
648 void GetTransactionAncestry(const uint256& txid, size_t& ancestors, size_t& descendants, size_t* ancestorsize = nullptr, CAmount* ancestorfees = nullptr) const;
649 650 /**
651 * @returns true if an initial attempt to load the persisted mempool was made, regardless of
652 * whether the attempt was successful or not
653 */
654 bool GetLoadTried() const;
655 656 /**
657 * Set whether or not an initial attempt to load the persisted mempool was made (regardless
658 * of whether the attempt was successful or not)
659 */
660 void SetLoadTried(bool load_tried);
661 662 unsigned long size() const
663 {
664 LOCK(cs);
665 return mapTx.size();
666 }
667 668 uint64_t GetTotalTxSize() const EXCLUSIVE_LOCKS_REQUIRED(cs)
669 {
670 AssertLockHeld(cs);
671 return totalTxSize;
672 }
673 674 CAmount GetTotalFee() const EXCLUSIVE_LOCKS_REQUIRED(cs)
675 {
676 AssertLockHeld(cs);
677 return m_total_fee;
678 }
679 680 bool exists(const GenTxid& gtxid) const
681 {
682 LOCK(cs);
683 if (gtxid.IsWtxid()) {
684 return (mapTx.get<index_by_wtxid>().count(gtxid.GetHash()) != 0);
685 }
686 return (mapTx.count(gtxid.GetHash()) != 0);
687 }
688 689 const CTxMemPoolEntry* GetEntry(const Txid& txid) const LIFETIMEBOUND EXCLUSIVE_LOCKS_REQUIRED(cs);
690 691 CTransactionRef get(const uint256& hash) const;
692 txiter get_iter_from_wtxid(const uint256& wtxid) const EXCLUSIVE_LOCKS_REQUIRED(cs)
693 {
694 AssertLockHeld(cs);
695 return mapTx.project<0>(mapTx.get<index_by_wtxid>().find(wtxid));
696 }
697 TxMempoolInfo info(const GenTxid& gtxid) const;
698 699 /** Returns info for a transaction if its entry_sequence < last_sequence */
700 TxMempoolInfo info_for_relay(const GenTxid& gtxid, uint64_t last_sequence) const;
701 702 std::vector<CTxMemPoolEntryRef> entryAll() const EXCLUSIVE_LOCKS_REQUIRED(cs);
703 std::vector<TxMempoolInfo> infoAll() const;
704 705 void FindScriptPubKey(const std::set<CScript>& needles, std::map<COutPoint, Coin>& out_results);
706 707 size_t DynamicMemoryUsage() const;
708 709 /** Adds a transaction to the unbroadcast set */
710 void AddUnbroadcastTx(const uint256& txid)
711 {
712 LOCK(cs);
713 // Sanity check the transaction is in the mempool & insert into
714 // unbroadcast set.
715 if (exists(GenTxid::Txid(txid))) m_unbroadcast_txids.insert(txid);
716 };
717 718 /** Removes a transaction from the unbroadcast set */
719 void RemoveUnbroadcastTx(const uint256& txid, const bool unchecked = false);
720 721 /** Returns transactions in unbroadcast set */
722 std::set<uint256> GetUnbroadcastTxs() const
723 {
724 LOCK(cs);
725 return m_unbroadcast_txids;
726 }
727 728 /** Returns whether a txid is in the unbroadcast set */
729 bool IsUnbroadcastTx(const uint256& txid) const EXCLUSIVE_LOCKS_REQUIRED(cs)
730 {
731 AssertLockHeld(cs);
732 return m_unbroadcast_txids.count(txid) != 0;
733 }
734 735 /** Guards this internal counter for external reporting */
736 uint64_t GetAndIncrementSequence() const EXCLUSIVE_LOCKS_REQUIRED(cs) {
737 return m_sequence_number++;
738 }
739 740 uint64_t GetSequence() const EXCLUSIVE_LOCKS_REQUIRED(cs) {
741 return m_sequence_number;
742 }
743 744 /* Check that all direct conflicts are in a cluster size of two or less. Each
745 * direct conflict may be in a separate cluster.
746 */
747 std::optional<std::string> CheckConflictTopology(const setEntries& direct_conflicts);
748 749 private:
750 /** Remove a set of transactions from the mempool.
751 * If a transaction is in this set, then all in-mempool descendants must
752 * also be in the set, unless this transaction is being removed for being
753 * in a block.
754 * Set updateDescendants to true when removing a tx that was in a block, so
755 * that any in-mempool descendants have their ancestor state updated.
756 */
757 void RemoveStaged(setEntries& stage, bool updateDescendants, MemPoolRemovalReason reason) EXCLUSIVE_LOCKS_REQUIRED(cs);
758 759 /** UpdateForDescendants is used by UpdateTransactionsFromBlock to update
760 * the descendants for a single transaction that has been added to the
761 * mempool but may have child transactions in the mempool, eg during a
762 * chain reorg.
763 *
764 * @pre CTxMemPoolEntry::m_children is correct for the given tx and all
765 * descendants.
766 * @pre cachedDescendants is an accurate cache where each entry has all
767 * descendants of the corresponding key, including those that should
768 * be removed for violation of ancestor limits.
769 * @post if updateIt has any non-excluded descendants, cachedDescendants has
770 * a new cache line for updateIt.
771 * @post descendants_to_remove has a new entry for any descendant which exceeded
772 * ancestor limits relative to updateIt.
773 *
774 * @param[in] updateIt the entry to update for its descendants
775 * @param[in,out] cachedDescendants a cache where each line corresponds to all
776 * descendants. It will be updated with the descendants of the transaction
777 * being updated, so that future invocations don't need to walk the same
778 * transaction again, if encountered in another transaction chain.
779 * @param[in] setExclude the set of descendant transactions in the mempool
780 * that must not be accounted for (because any descendants in setExclude
781 * were added to the mempool after the transaction being updated and hence
782 * their state is already reflected in the parent state).
783 * @param[out] descendants_to_remove Populated with the txids of entries that
784 * exceed ancestor limits. It's the responsibility of the caller to
785 * removeRecursive them.
786 */
787 void UpdateForDescendants(txiter updateIt, cacheMap& cachedDescendants,
788 const std::set<uint256>& setExclude, std::set<uint256>& descendants_to_remove) EXCLUSIVE_LOCKS_REQUIRED(cs);
789 /** Update ancestors of hash to add/remove it as a descendant transaction. */
790 void UpdateAncestorsOf(bool add, txiter hash, setEntries &setAncestors) EXCLUSIVE_LOCKS_REQUIRED(cs);
791 /** Set ancestor state for an entry */
792 void UpdateEntryForAncestors(txiter it, const setEntries &setAncestors) EXCLUSIVE_LOCKS_REQUIRED(cs);
793 /** For each transaction being removed, update ancestors and any direct children.
794 * If updateDescendants is true, then also update in-mempool descendants'
795 * ancestor state. */
796 void UpdateForRemoveFromMempool(const setEntries &entriesToRemove, bool updateDescendants) EXCLUSIVE_LOCKS_REQUIRED(cs);
797 /** Sever link between specified transaction and direct children. */
798 void UpdateChildrenForRemoval(txiter entry) EXCLUSIVE_LOCKS_REQUIRED(cs);
799 800 /** Before calling removeUnchecked for a given transaction,
801 * UpdateForRemoveFromMempool must be called on the entire (dependent) set
802 * of transactions being removed at the same time. We use each
803 * CTxMemPoolEntry's m_parents in order to walk ancestors of a
804 * given transaction that is removed, so we can't remove intermediate
805 * transactions in a chain before we've updated all the state for the
806 * removal.
807 */
808 void removeUnchecked(txiter entry, MemPoolRemovalReason reason) EXCLUSIVE_LOCKS_REQUIRED(cs);
809 public:
810 /** visited marks a CTxMemPoolEntry as having been traversed
811 * during the lifetime of the most recently created Epoch::Guard
812 * and returns false if we are the first visitor, true otherwise.
813 *
814 * An Epoch::Guard must be held when visited is called or an assert will be
815 * triggered.
816 *
817 */
818 bool visited(const txiter it) const EXCLUSIVE_LOCKS_REQUIRED(cs, m_epoch)
819 {
820 return m_epoch.visited(it->m_epoch_marker);
821 }
822 823 bool visited(std::optional<txiter> it) const EXCLUSIVE_LOCKS_REQUIRED(cs, m_epoch)
824 {
825 assert(m_epoch.guarded()); // verify guard even when it==nullopt
826 return !it || visited(*it);
827 }
828 829 /*
830 * CTxMemPool::ChangeSet:
831 *
832 * This class is used for all mempool additions and associated removals (eg
833 * due to rbf). Removals that don't need to be evaluated for acceptance,
834 * such as removing transactions that appear in a block, or due to reorg,
835 * or removals related to mempool limiting or expiry do not need to use
836 * this.
837 *
838 * Callers can interleave calls to StageAddition()/StageRemoval(), and
839 * removals may be invoked in any order, but additions must be done in a
840 * topological order in the case of transaction packages (ie, parents must
841 * be added before children).
842 *
843 * CalculateChunksForRBF() can be used to calculate the feerate diagram of
844 * the proposed set of new transactions and compare with the existing
845 * mempool.
846 *
847 * CalculateMemPoolAncestors() calculates the in-mempool (not including
848 * what is in the change set itself) ancestors of a given transaction.
849 *
850 * Apply() will apply the removals and additions that are staged into the
851 * mempool.
852 *
853 * Only one changeset may exist at a time. While a changeset is
854 * outstanding, no removals or additions may be made directly to the
855 * mempool.
856 */
857 class ChangeSet {
858 public:
859 explicit ChangeSet(CTxMemPool* pool) : m_pool(pool) {}
860 ~ChangeSet() EXCLUSIVE_LOCKS_REQUIRED(m_pool->cs) { m_pool->m_have_changeset = false; }
861 862 ChangeSet(const ChangeSet&) = delete;
863 ChangeSet& operator=(const ChangeSet&) = delete;
864 865 using TxHandle = CTxMemPool::txiter;
866 867 TxHandle StageAddition(const CTransactionRef& tx, const CAmount fee, int64_t time, unsigned int entry_height, uint64_t entry_sequence, CoinAgeCache coin_age_cache, bool spends_coinbase, int32_t extra_weight, int64_t sigops_cost, LockPoints lp);
868 void StageRemoval(CTxMemPool::txiter it) { m_to_remove.insert(it); }
869 870 const CTxMemPool::setEntries& GetRemovals() const { return m_to_remove; }
871 872 util::Result<CTxMemPool::setEntries> CalculateMemPoolAncestors(TxHandle tx, const Limits& limits)
873 {
874 // Look up transaction in our cache first
875 auto it = m_ancestors.find(tx);
876 if (it != m_ancestors.end()) return it->second;
877 878 // If not found, try to have the mempool calculate it, and cache
879 // for later.
880 LOCK(m_pool->cs);
881 auto ret{m_pool->CalculateMemPoolAncestors(*tx, limits)};
882 if (ret) m_ancestors.try_emplace(tx, *ret);
883 return ret;
884 }
885 886 std::vector<CTransactionRef> GetAddedTxns() const {
887 std::vector<CTransactionRef> ret;
888 ret.reserve(m_entry_vec.size());
889 for (const auto& entry : m_entry_vec) {
890 ret.emplace_back(entry->GetSharedTx());
891 }
892 return ret;
893 }
894 895 /**
896 * Calculate the sorted chunks for the old and new mempool relating to the
897 * clusters that would be affected by a potential replacement transaction.
898 *
899 * @return old and new diagram pair respectively, or an error string if the conflicts don't match a calculable topology
900 */
901 util::Result<std::pair<std::vector<FeeFrac>, std::vector<FeeFrac>>> CalculateChunksForRBF();
902 903 size_t GetTxCount() const { return m_entry_vec.size(); }
904 const CTransaction& GetAddedTxn(size_t index) const { return m_entry_vec.at(index)->GetTx(); }
905 906 void Apply() EXCLUSIVE_LOCKS_REQUIRED(cs_main);
907 908 CTxMemPool* m_pool;
909 CTxMemPool::indexed_transaction_set m_to_add;
910 private:
911 std::vector<CTxMemPool::txiter> m_entry_vec; // track the added transactions' insertion order
912 // map from the m_to_add index to the ancestors for the transaction
913 std::map<CTxMemPool::txiter, CTxMemPool::setEntries, CompareIteratorByHash> m_ancestors;
914 CTxMemPool::setEntries m_to_remove;
915 916 friend class CTxMemPool;
917 };
918 919 std::unique_ptr<ChangeSet> GetChangeSet() EXCLUSIVE_LOCKS_REQUIRED(cs) {
920 Assume(!m_have_changeset);
921 m_have_changeset = true;
922 return std::make_unique<ChangeSet>(this);
923 }
924 925 bool m_have_changeset GUARDED_BY(cs){false};
926 927 friend class CTxMemPool::ChangeSet;
928 929 private:
930 // Apply the given changeset to the mempool, by removing transactions in
931 // the to_remove set and adding transactions in the to_add set.
932 void Apply(CTxMemPool::ChangeSet* changeset) EXCLUSIVE_LOCKS_REQUIRED(cs);
933 934 // addNewTransaction must update state for all ancestors of a given transaction,
935 // to track size/count of descendant transactions. First version of
936 // addNewTransaction can be used to have it call CalculateMemPoolAncestors(), and
937 // then invoke the second version.
938 // Note that addNewTransaction is ONLY called (via Apply()) from ATMP
939 // outside of tests and any other callers may break wallet's in-mempool
940 // tracking (due to lack of CValidationInterface::TransactionAddedToMempool
941 // callbacks).
942 void addNewTransaction(CTxMemPool::txiter it) EXCLUSIVE_LOCKS_REQUIRED(cs);
943 void addNewTransaction(CTxMemPool::txiter it, CTxMemPool::setEntries& setAncestors) EXCLUSIVE_LOCKS_REQUIRED(cs);
944 };
945 946 /**
947 * CCoinsView that brings transactions from a mempool into view.
948 * It does not check for spendings by memory pool transactions.
949 * Instead, it provides access to all Coins which are either unspent in the
950 * base CCoinsView, are outputs from any mempool transaction, or are
951 * tracked temporarily to allow transaction dependencies in package validation.
952 * This allows transaction replacement to work as expected, as you want to
953 * have all inputs "available" to check signatures, and any cycles in the
954 * dependency graph are checked directly in AcceptToMemoryPool.
955 * It also allows you to sign a double-spend directly in
956 * signrawtransactionwithkey and signrawtransactionwithwallet,
957 * as long as the conflicting transaction is not yet confirmed.
958 *
959 * Its Cursor also doesn't work. In general, it is broken as a CCoinsView
960 * implementation outside of a few use cases.
961 */
962 class CCoinsViewMemPool : public CCoinsViewBacked
963 {
964 /**
965 * Coins made available by transactions being validated. Tracking these allows for package
966 * validation, since we can access transaction outputs without submitting them to mempool.
967 */
968 std::unordered_map<COutPoint, Coin, SaltedOutpointHasher> m_temp_added;
969 970 /**
971 * Set of all coins that have been fetched from mempool or created using PackageAddTransaction
972 * (not base). Used to track the origin of a coin, see GetNonBaseCoins().
973 */
974 mutable std::unordered_set<COutPoint, SaltedOutpointHasher> m_non_base_coins;
975 protected:
976 const CTxMemPool& mempool;
977 978 public:
979 CCoinsViewMemPool(CCoinsView* baseIn, const CTxMemPool& mempoolIn);
980 /** GetCoin, returning whether it exists and is not spent. Also updates m_non_base_coins if the
981 * coin is not fetched from base. */
982 std::optional<Coin> GetCoin(const COutPoint& outpoint) const override;
983 /** Add the coins created by this transaction. These coins are only temporarily stored in
984 * m_temp_added and cannot be flushed to the back end. Only used for package validation. */
985 void PackageAddTransaction(const CTransactionRef& tx);
986 /** Get all coins in m_non_base_coins. */
987 std::unordered_set<COutPoint, SaltedOutpointHasher> GetNonBaseCoins() const { return m_non_base_coins; }
988 /** Clear m_temp_added and m_non_base_coins. */
989 void Reset();
990 };
991 #endif // LIMENKA_TXMEMPOOL_H
992