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1// Copyright (c) 2009-2010 Satoshi Nakamoto
2// Copyright (c) 2009-present 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 <primitives/transaction_identifier.h>
21#include <sync.h>
22#include <txgraph.h>
23#include <util/feefrac.h>
24#include <util/hasher.h>
25#include <util/result.h>
26
27#include <boost/multi_index/hashed_index.hpp>
28#include <boost/multi_index/identity.hpp>
29#include <boost/multi_index/indexed_by.hpp>
30#include <boost/multi_index/ordered_index.hpp>
31#include <boost/multi_index/sequenced_index.hpp>
32#include <boost/multi_index/tag.hpp>
33#include <boost/multi_index_container.hpp>
34
35#include <atomic>
36#include <map>
37#include <optional>
38#include <set>
39#include <string>
40#include <string_view>
41#include <utility>
42#include <vector>
43
44class CChain;
45class ValidationSignals;
46
47struct bilingual_str;
48
49/** Fake height value used in Coin to signify they are only in the memory pool (since 0.8) */
50inline constexpr uint32_t MEMPOOL_HEIGHT = 0x7FFFFFFF;
51
52/** How much linearization cost required for TxGraph clusters to have
53 * "acceptable" quality, if they cannot be optimally linearized with less cost. */
54inline constexpr uint64_t ACCEPTABLE_COST = 75'000;
55
56/** How much work we ask TxGraph to do after a mempool change occurs (either
57 * due to a changeset being applied, a new block being found, or a reorg). */
58inline constexpr uint64_t POST_CHANGE_COST = 5 * ACCEPTABLE_COST;
59
60/**
61 * Test whether the LockPoints height and time are still valid on the current chain
62 */
63bool TestLockPointValidity(CChain& active_chain, const LockPoints& lp) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
64
65// extracts a transaction hash from CTxMemPoolEntry or CTransactionRef
66struct mempoolentry_txid
67{
68    typedef Txid result_type;
69    result_type operator() (const CTxMemPoolEntry &entry) const
70    {
71        return entry.GetTx().GetHash();
72    }
73
74    result_type operator() (const CTransactionRef& tx) const
75    {
76        return tx->GetHash();
77    }
78};
79
80// extracts a transaction witness-hash from CTxMemPoolEntry or CTransactionRef
81struct mempoolentry_wtxid
82{
83    typedef Wtxid result_type;
84    result_type operator() (const CTxMemPoolEntry &entry) const
85    {
86        return entry.GetTx().GetWitnessHash();
87    }
88
89    result_type operator() (const CTransactionRef& tx) const
90    {
91        return tx->GetWitnessHash();
92    }
93};
94
95class CompareTxMemPoolEntryByEntryTime
96{
97public:
98    bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const
99    {
100        return a.GetTime() < b.GetTime();
101    }
102};
103
104// Multi_index tag names
105struct entry_time {};
106struct index_by_wtxid {};
107
108/**
109 * Information about a mempool transaction.
110 */
111struct TxMempoolInfo
112{
113    /** The transaction itself */
114    CTransactionRef tx;
115
116    /** Time the transaction entered the mempool. */
117    std::chrono::seconds m_time;
118
119    /** Fee of the transaction. */
120    CAmount fee;
121
122    /** Virtual size of the transaction. */
123    int32_t vsize;
124
125    /** The fee delta. */
126    int64_t nFeeDelta;
127};
128
129/**
130 * CTxMemPool stores valid-according-to-the-current-best-chain transactions
131 * that may be included in the next block.
132 *
133 * Transactions are added when they are seen on the network (or created by the
134 * local node), but not all transactions seen are added to the pool. For
135 * example, the following new transactions will not be added to the mempool:
136 * - a transaction which doesn't meet the minimum fee requirements.
137 * - a new transaction that double-spends an input of a transaction already in
138 * the pool where the new transaction does not meet the Replace-By-Fee
139 * requirements as defined in doc/policy/mempool-replacements.md.
140 * - a non-standard transaction.
141 *
142 * TxGraph (CTxMemPool::m_txgraph) provides an abstraction layer for separating
143 * the transaction graph parts of the mempool from the rest of the
144 * Bitcoin-specific logic. Specifically, TxGraph handles (for each transaction)
145 * managing the in-mempool parents and children, and has knowledge of the fee
146 * and size of every transaction. It uses this to partition the mempool into
147 * connected clusters, and it implements (among other things):
148 *  - limits on the size of a cluster (in both number of transactions
149 *    and total weight)
150 *  - sorting the mempool optimally for block inclusion, taking into account
151 *    dependencies
152 *  - selecting transactions for removal due to cluster size limit violations
153 *    after a reorg.
154 * See txgraph.h and txgraph.cpp for more details.
155 *
156 * CTxMemPool itself handles the Bitcoin-specific parts of mempool
157 * transactions; it stores the full transaction inside CTxMemPoolEntry, along
158 * with other consensus-specific fields (such as whether a transaction spends a
159 * coinbase, or the LockPoints for transaction finality). And it provides
160 * interfaces to the rest of the codebase, such as:
161 *  - to validation for replace-by-fee calculations and cluster size limits
162 *    when evaluating unconfirmed transactions
163 *  - to validation for evicting transactions due to expiry or the mempool size
164 *    limit being hit
165 *  - to validation for updating the mempool to be consistent with the best
166 *    chain after a new block is connected or after a reorg.
167 *  - to net_processing for ordering transactions that are to-be-announced to
168 *    other peers
169 *  - to RPC code for inspecting the mempool
170 *
171 * (Many of these interfaces are just wrappers around corresponding TxGraph
172 * functions.)
173 *
174 * Within CTxMemPool, the mempool entries are stored in a boost::multi_index
175 * mapTx, which sorts the mempool on 3 criteria:
176 * - transaction hash (txid)
177 * - witness-transaction hash (wtxid)
178 * - time in mempool
179 *
180 * We also maintain a map from COutPoint to the (in-mempool) transaction that
181 * spends it (mapNextTx). This allows us to recover from a reorg and find
182 * transactions in the mempool that conflict with transactions that are
183 * confirmed in a block.
184 *
185 */
186class CTxMemPool
187{
188protected:
189    std::atomic<unsigned int> nTransactionsUpdated{0}; //!< Used by getblocktemplate to trigger CreateNewBlock() invocation
190
191    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.
192    CAmount m_total_fee GUARDED_BY(cs){0};       //!< sum of all mempool tx's fees (NOT modified fee)
193    uint64_t cachedInnerUsage GUARDED_BY(cs){0}; //!< sum of dynamic memory usage of all the map elements (NOT the maps themselves)
194
195    mutable int64_t lastRollingFeeUpdate GUARDED_BY(cs){GetTime()};
196    mutable bool blockSinceLastRollingFeeBump GUARDED_BY(cs){false};
197    mutable double rollingMinimumFeeRate GUARDED_BY(cs){0}; //!< minimum fee to get into the pool, decreases exponentially
198
199    // In-memory counter for external mempool tracking purposes.
200    // This number is incremented once every time a transaction
201    // is added or removed from the mempool for any reason.
202    mutable uint64_t m_sequence_number GUARDED_BY(cs){1};
203
204    void trackPackageRemoved(const CFeeRate& rate) EXCLUSIVE_LOCKS_REQUIRED(cs);
205
206    bool m_load_tried GUARDED_BY(cs){false};
207
208    CFeeRate GetMinFee(size_t sizelimit) const;
209
210public:
211
212    static constexpr int ROLLING_FEE_HALFLIFE{60 * 60 * 12}; // public only for testing
213
214    using indexed_transaction_set = boost::multi_index_container<
215        CTxMemPoolEntry,
216        boost::multi_index::indexed_by<
217            // sorted by txid
218            boost::multi_index::hashed_unique<mempoolentry_txid, SaltedTxidHasher>,
219            // sorted by wtxid
220            boost::multi_index::hashed_unique<
221                boost::multi_index::tag<index_by_wtxid>,
222                mempoolentry_wtxid,
223                SaltedWtxidHasher
224            >,
225            // sorted by entry time
226            boost::multi_index::ordered_non_unique<
227                boost::multi_index::tag<entry_time>,
228                boost::multi_index::identity<CTxMemPoolEntry>,
229                CompareTxMemPoolEntryByEntryTime
230            >
231        >
232    >;
233
234    /**
235     * This mutex needs to be locked when accessing `mapTx` or other members
236     * that are guarded by it.
237     *
238     * @par Consistency guarantees
239     * By design, it is guaranteed that:
240     * 1. Locking both `cs_main` and `mempool.cs` will give a view of mempool
241     *    that is consistent with current chain tip (`ActiveChain()` and
242     *    `CoinsTip()`) and is fully populated. Fully populated means that if the
243     *    current active chain is missing transactions that were present in a
244     *    previously active chain, all the missing transactions will have been
245     *    re-added to the mempool and should be present if they meet size and
246     *    consistency constraints.
247     * 2. Locking `mempool.cs` without `cs_main` will give a view of a mempool
248     *    consistent with some chain that was active since `cs_main` was last
249     *    locked, and that is fully populated as described above. It is ok for
250     *    code that only needs to query or remove transactions from the mempool

src/wallet/receive.cpp

src/wallet/coinselection.cpp

src/consensus/validation.h

src/primitives/transaction.cpp

src/script/descriptor.cpp

src/bitcoin-cli.cpp

src/rpc/blockchain.cpp

src/rpc/rawtransaction.cpp

src/init.cpp

src/crypto/sha256.cpp

src/consensus/merkle.h

src/consensus/tx_check.h

src/consensus/tx_verify.h

src/policy/feerate.h

src/policy/feerate.cpp

src/primitives/transaction_identifier.h

src/chainparamsbase.h

src/chainparamsbase.cpp

src/util/moneystr.cpp

src/crypto/ripemd160.h

src/crypto/sha1.h

src/crypto/sha512.h

src/crypto/hmac_sha256.h

src/crypto/hmac_sha512.h

src/crypto/hmac_sha256.cpp

src/crypto/hmac_sha512.cpp

src/crypto/hkdf_sha256_32.h

src/crypto/hkdf_sha256_32.cpp

src/support/cleanse.h

src/support/cleanse.cpp

src/crypto/siphash.cpp

src/crypto/muhash.h

src/crypto/chacha20.h

src/crypto/poly1305.h

src/crypto/chacha20poly1305.h

src/crypto/chacha20poly1305.cpp

src/util/chaintype.cpp

src/util/obfuscation.h

src/util/byte_units.h

src/util/overflow.h

src/blockencodings.cpp

src/net_permissions.cpp

src/policy/packages.cpp

src/policy/rbf.cpp

src/policy/truc_policy.cpp

src/policy/ephemeral_policy.cpp

src/policy/settings.cpp

src/policy/policy.cpp

src/node/transaction.cpp

src/node/coin.cpp

src/rpc/client.cpp

src/rpc/external_signer.cpp

src/rpc/request.cpp

src/rpc/server_util.cpp

src/rpc/fees.cpp

src/rpc/output_script.cpp

src/rpc/rawtransaction_util.cpp

src/rpc/rawtransaction_util.h

src/rpc/register.h

src/rpc/request.h

src/rpc/server_util.h

src/rpc/protocol.h

src/rpc/server.h

src/rpc/signmessage.cpp

src/rpc/txoutproof.cpp

src/rpc/util.cpp

src/rpc/util.h

src/wallet/rpc/addresses.cpp

src/wallet/rpc/backup.cpp

src/wallet/rpc/coins.cpp

src/wallet/rpc/encrypt.cpp

src/wallet/rpc/signmessage.cpp

src/wallet/rpc/util.cpp

src/wallet/rpc/util.h

src/wallet/coincontrol.cpp

src/wallet/coincontrol.h

src/wallet/context.cpp

src/wallet/context.h

src/wallet/crypter.cpp

src/wallet/crypter.h

src/wallet/db.cpp

src/wallet/export.cpp

src/wallet/external_signer_scriptpubkeyman.cpp

src/wallet/rpc/spend.cpp

src/wallet/rpc/transactions.cpp

src/wallet/rpc/wallet.cpp

src/wallet/feebumper.cpp

src/wallet/feebumper.h

src/index/base.h

src/index/base.cpp

src/index/txindex.h

src/index/txindex.cpp

src/index/txindex_key.h

src/index/txospenderindex.h

src/index/txospenderindex.cpp

src/index/blockfilterindex.h

src/index/blockfilterindex.cpp

src/index/coinstatsindex.h

src/index/coinstatsindex.cpp

src/index/db_key.h

src/index/disktxpos.h

src/kernel/chain.cpp

src/kernel/chain.h

src/kernel/checks.cpp

src/kernel/checks.h

src/kernel/context.cpp

src/kernel/context.h

src/kernel/cs_main.cpp

src/kernel/cs_main.h

src/kernel/disconnected_transactions.cpp

src/kernel/disconnected_transactions.h

src/kernel/mempool_removal_reason.cpp

src/kernel/mempool_removal_reason.h

src/kernel/coinstats.cpp

src/kernel/coinstats.h

src/kernel/chainparams.cpp

src/kernel/chainparams.h

src/wallet/sqlite.cpp

src/wallet/sqlite.h

src/wallet/transaction.cpp

src/wallet/transaction.h

src/wallet/dump.cpp

src/wallet/dump.h

src/wallet/init.cpp

src/wallet/walletutil.cpp

src/wallet/walletutil.h

src/wallet/wallettool.cpp

src/wallet/wallettool.h

src/wallet/export.h

src/wallet/migrate.cpp

src/wallet/migrate.h

src/wallet/db.h

src/wallet/walletdb.cpp

src/wallet/interfaces.cpp

src/wallet/scriptpubkeyman.cpp

src/wallet/scriptpubkeyman.h

src/kernel/bitcoinkernel.cpp

src/kernel/bitcoinkernel.h

src/kernel/bitcoinkernel_wrapper.h

src/node/chainstate.cpp

src/node/chainstate.h

src/node/blockstorage.cpp

src/node/blockstorage.h

src/node/mempool_persist.cpp

src/node/mempool_persist.h

src/node/utxo_snapshot.cpp

src/node/utxo_snapshot.h

src/node/kernel_notifications.cpp

src/node/kernel_notifications.h

src/node/blockmanager_args.cpp

src/kernel/blockmanager_opts.h

src/util/expected.cpp

src/policy/settings.h

src/util/types.h

src/kernel/messagestartchars.h

src/kernel/warning.h

src/util/exception.h

src/common/license_info.h

src/node/coins_view_args.h

src/node/database_args.h

src/util/batchpriority.h

src/util/ui_change_type.h

src/node/coins_view_args.cpp

src/node/peerman_args.h

src/util/serfloat.h

src/node/blockmanager_args.h

src/node/database_args.cpp

src/util/overloaded.h

src/interfaces/types.h

src/node/chainstatemanager_args.h

src/node/minisketchwrapper.h

src/util/macros.h

src/util/syserror.h

src/common/run_command.h

src/util/bytevectorhash.cpp

src/node/mempool_persist_args.cpp

src/util/exec.h

src/util/rbf.h

src/crypto/hex_base.h

src/node/mempool_persist_args.h

src/interfaces/echo.h

src/util/any.h

src/util/batchpriority.cpp

src/util/threadnames.h

src/node/coin.h

src/node/mempool_args.h

src/util/asmap.h

src/util/bytevectorhash.h

src/node/context.cpp

src/util/insert.h

src/util/readwritefile.h

src/node/peerman_args.cpp

src/node/interface_ui.cpp

src/interfaces/handler.h

src/node/mining_args.h

src/util/hasher.cpp

src/common/init.h

src/kernel/mempool_limits.h

src/common/system.h

src/crypto/sha3.h

src/util/threadinterrupt.cpp

src/node/protocol_version.h

src/util/exception.cpp

src/common/messages.h

src/node/connection_types.cpp

src/util/bip32.h

src/common/license_info.cpp

src/util/stdmutex.h

src/common/run_command.cpp

src/util/check.cpp

src/util/golombrice.h

src/node/types.h

src/node/timeoffsets.h

src/util/readwritefile.cpp

src/util/fastrange.h

src/util/signalinterrupt.h

src/util/task_runner.h

src/util/syserror.cpp

src/common/interfaces.cpp

src/common/types.h

src/util/threadinterrupt.h

src/kernel/chainstatemanager_opts.h

src/node/psbt.h

src/policy/ephemeral_policy.h

src/util/trace.h

src/common/url.cpp

src/kernel/mempool_options.h

src/util/serfloat.cpp

src/kernel/notifications_interface.h

src/node/timeoffsets.cpp

src/node/warnings.cpp

src/util/hash_type.h

src/crypto/hex_base.cpp

src/node/eviction.h

src/util/tokenbucket.h

src/crypto/aes.h

src/common/pcp.h

src/util/feefrac.cpp

src/node/transaction.h

src/util/threadnames.cpp

src/common/signmessage.h

src/util/exec.cpp

src/util/signalinterrupt.cpp

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