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1// Copyright (c) 2024-present The Bitcoin Core developers
2// Distributed under the MIT software license, see the accompanying
3// file COPYING or http://www.opensource.org/licenses/mit-license.php.
4#ifndef BITCOIN_NODE_TXDOWNLOADMAN_IMPL_H
5#define BITCOIN_NODE_TXDOWNLOADMAN_IMPL_H
6
7#include <node/txdownloadman.h>
8
9#include <common/bloom.h>
10#include <consensus/validation.h>
11#include <kernel/chain.h>
12#include <net.h>
13#include <node/txorphanage.h>
14#include <primitives/transaction.h>
15#include <policy/packages.h>
16#include <random.h>
17#include <txrequest.h>
18
19class CTxMemPool;
20namespace node {
21class TxDownloadManagerImpl {
22public:
23    const CTxMemPool& m_mempool;
24    FastRandomContext m_rng;
25
26    /** Manages unvalidated tx data (orphan transactions for which we are downloading ancestors). */
27    std::unique_ptr<TxOrphanage> m_orphanage;
28    /** Tracks candidates for requesting and downloading transaction data. */
29    TxRequestTracker m_txrequest;
30
31    /**
32     * Filter for transactions that were recently rejected by the mempool.
33     * These are not rerequested until the chain tip changes, at which point
34     * the entire filter is reset.
35     *
36     * Without this filter we'd be re-requesting txs from each of our peers,
37     * increasing bandwidth consumption considerably. For instance, with 100
38     * peers, half of which relay a tx we don't accept, that might be a 50x
39     * bandwidth increase. A flooding attacker attempting to roll-over the
40     * filter using minimum-sized, 60byte, transactions might manage to send
41     * 1000/sec if we have fast peers, so we pick 120,000 to give our peers a
42     * two minute window to send invs to us.
43     *
44     * Decreasing the false positive rate is fairly cheap, so we pick one in a
45     * million to make it highly unlikely for users to have issues with this
46     * filter.
47     *
48     * We typically only add wtxids to this filter. For non-segwit
49     * transactions, the txid == wtxid, so this only prevents us from
50     * re-downloading non-segwit transactions when communicating with
51     * non-wtxidrelay peers -- which is important for avoiding malleation
52     * attacks that could otherwise interfere with transaction relay from
53     * non-wtxidrelay peers. For communicating with wtxidrelay peers, having
54     * the reject filter store wtxids is exactly what we want to avoid
55     * redownload of a rejected transaction.
56     *
57     * In cases where we can tell that a segwit transaction will fail
58     * validation no matter the witness, we may add the txid of such
59     * transaction to the filter as well. This can be helpful when
60     * communicating with txid-relay peers or if we were to otherwise fetch a
61     * transaction via txid (eg in our orphan handling).
62     *
63     * Memory used: 1.3 MB
64     */
65    std::unique_ptr<CRollingBloomFilter> m_lazy_recent_rejects{nullptr};
66
67    CRollingBloomFilter& RecentRejectsFilter()
68    {
69        if (!m_lazy_recent_rejects) {
70            m_lazy_recent_rejects = std::make_unique<CRollingBloomFilter>(120'000, 0.000'001);
71        }
72
73        return *m_lazy_recent_rejects;
74    }
75
76    /**
77     * Filter for:
78     * (1) wtxids of transactions that were recently rejected by the mempool but are
79     * eligible for reconsideration if submitted with other transactions.
80     * (2) packages (see GetPackageHash) we have already rejected before and should not retry.
81     *
82     * Similar to m_lazy_recent_rejects, this filter is used to save bandwidth when e.g. all of our peers
83     * have larger mempools and thus lower minimum feerates than us.
84     *
85     * When a transaction's error is TxValidationResult::TX_RECONSIDERABLE (in a package or by
86     * itself), add its wtxid to this filter. When a package fails for any reason, add the combined
87     * hash to this filter.
88     *
89     * Upon receiving an announcement for a transaction, if it exists in this filter, do not
90     * download the txdata. When considering packages, if it exists in this filter, drop it.
91     *
92     * Reset this filter when the chain tip changes.
93     *
94     * Parameters are picked to be the same as m_lazy_recent_rejects, with the same rationale.
95     */
96    std::unique_ptr<CRollingBloomFilter> m_lazy_recent_rejects_reconsiderable{nullptr};
97
98    CRollingBloomFilter& RecentRejectsReconsiderableFilter()
99    {
100        if (!m_lazy_recent_rejects_reconsiderable) {
101            m_lazy_recent_rejects_reconsiderable = std::make_unique<CRollingBloomFilter>(120'000, 0.000'001);
102        }
103
104        return *m_lazy_recent_rejects_reconsiderable;
105    }
106
107    /*
108     * Filter for transactions that have been recently confirmed.
109     * We use this to avoid requesting transactions that have already been
110     * confirmed.
111     *
112     * Blocks don't typically have more than 4000 transactions, so this should
113     * be at least six blocks (~1 hr) worth of transactions that we can store,
114     * inserting both a txid and wtxid for every observed transaction.
115     * If the number of transactions appearing in a block goes up, or if we are
116     * seeing getdata requests more than an hour after initial announcement, we
117     * can increase this number.
118     * The false positive rate of 1/1M should come out to less than 1
119     * transaction per day that would be inadvertently ignored (which is the
120     * same probability that we have in the reject filter).
121     */
122    std::unique_ptr<CRollingBloomFilter> m_lazy_recent_confirmed_transactions{nullptr};
123
124    CRollingBloomFilter& RecentConfirmedTransactionsFilter()
125    {
126        if (!m_lazy_recent_confirmed_transactions) {
127            m_lazy_recent_confirmed_transactions = std::make_unique<CRollingBloomFilter>(48'000, 0.000'001);
128        }
129
130        return *m_lazy_recent_confirmed_transactions;
131    }
132
133    TxDownloadManagerImpl(const TxDownloadOptions& options)
134        : m_mempool{options.m_mempool},
135          m_rng{options.m_deterministic_txrequest},
136          m_orphanage{MakeTxOrphanage()},
137          m_txrequest{options.m_deterministic_txrequest}
138    {}
139
140    struct PeerInfo {
141        /** Information relevant to scheduling tx requests. */
142        const TxDownloadConnectionInfo m_connection_info;
143
144        PeerInfo(const TxDownloadConnectionInfo& info) : m_connection_info{info} {}
145    };
146
147    /** Information for all of the peers we may download transactions from. This is not necessarily
148     * all peers we are connected to (no block-relay-only and temporary connections). */
149    std::map<NodeId, PeerInfo> m_peer_info;
150
151    /** Number of wtxid relay peers we have in m_peer_info. */
152    uint32_t m_num_wtxid_peers{0};
153
154    void ActiveTipChange();
155    void BlockConnected(const std::shared_ptr<const CBlock>& pblock);
156    void BlockDisconnected();
157
158    /** Check whether we already have this gtxid in:
159     *  - mempool
160     *  - orphanage
161     *  - m_recent_rejects
162     *  - m_recent_rejects_reconsiderable (if include_reconsiderable = true)
163     *  - m_recent_confirmed_transactions
164     *  */
165    bool AlreadyHaveTx(const GenTxid& gtxid, bool include_reconsiderable);
166
167    void ConnectedPeer(NodeId nodeid, const TxDownloadConnectionInfo& info);
168    void DisconnectedPeer(NodeId nodeid);
169
170    /** Consider adding this tx hash to txrequest. Should be called whenever a new inv has been received.
171     * Also called internally when a transaction is missing parents so that we can request them.
172     */
173    bool AddTxAnnouncement(NodeId peer, const GenTxid& gtxid, std::chrono::microseconds now);
174
175    /** Get getdata requests to send. */
176    std::vector<GenTxid> GetRequestsToSend(NodeId nodeid, std::chrono::microseconds current_time);
177
178    /** Marks a tx as ReceivedResponse in txrequest. */
179    void ReceivedNotFound(NodeId nodeid, const std::vector<GenTxid>& gtxids);
180
181    /** Look for a child of this transaction in the orphanage to form a 1-parent-1-child package,
182     * skipping any combinations that have already been tried. Return the resulting package along with
183     * the senders of its respective transactions, or std::nullopt if no package is found. */
184    std::optional<PackageToValidate> Find1P1CPackage(const CTransactionRef& ptx, NodeId nodeid);
185
186    void MempoolAcceptedTx(const CTransactionRef& tx);
187    RejectedTxTodo MempoolRejectedTx(const CTransactionRef& ptx, const TxValidationState& state, NodeId nodeid, bool first_time_failure);
188    void MempoolRejectedPackage(const Package& package);
189
190    std::pair<bool, std::optional<PackageToValidate>> ReceivedTx(NodeId nodeid, const CTransactionRef& ptx);
191
192    bool HaveMoreWork(NodeId nodeid);
193    CTransactionRef GetTxToReconsider(NodeId nodeid);
194
195    void CheckIsEmpty();
196    void CheckIsEmpty(NodeId nodeid);
197
198    std::vector<TxOrphanage::OrphanInfo> GetOrphanTransactions() const;
199
200protected:
201    /** Helper for getting deduplicated vector of Txids in vin. */
202    std::vector<Txid> GetUniqueParents(const CTransaction& tx);
203
204    /** If this peer is an orphan resolution candidate for this transaction, treat the unique_parents as announced by
205     * this peer; add them as new invs to m_txrequest.
206     * @returns whether this transaction was a valid orphan resolution candidate.
207     * */
208    bool MaybeAddOrphanResolutionCandidate(const std::vector<Txid>& unique_parents, const Wtxid& wtxid, NodeId nodeid, std::chrono::microseconds now);
209};
210} // namespace node
211#endif // BITCOIN_NODE_TXDOWNLOADMAN_IMPL_H
212

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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