/root/bitcoin/src/node/txdownloadman_impl.h

Source (jump to first uncovered line)
// Copyright (c) 2024
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_NODE_TXDOWNLOADMAN_IMPL_H
#define BITCOIN_NODE_TXDOWNLOADMAN_IMPL_H

#include <node/txdownloadman.h>

#include <common/bloom.h>
#include <consensus/validation.h>
#include <kernel/chain.h>
#include <net.h>
#include <primitives/transaction.h>
#include <policy/packages.h>
#include <txorphanage.h>
#include <txrequest.h>

class CTxMemPool;
namespace node {
class TxDownloadManagerImpl {
public:
    TxDownloadOptions m_opts;

    /** Manages unvalidated tx data (orphan transactions for which we are downloading ancestors). */
    TxOrphanage m_orphanage;
    /** Tracks candidates for requesting and downloading transaction data. */
    TxRequestTracker m_txrequest;

    /**
     * Filter for transactions that were recently rejected by the mempool.
     * These are not rerequested until the chain tip changes, at which point
     * the entire filter is reset.
     *
     * Without this filter we'd be re-requesting txs from each of our peers,
     * increasing bandwidth consumption considerably. For instance, with 100
     * peers, half of which relay a tx we don't accept, that might be a 50x
     * bandwidth increase. A flooding attacker attempting to roll-over the
     * filter using minimum-sized, 60byte, transactions might manage to send
     * 1000/sec if we have fast peers, so we pick 120,000 to give our peers a
     * two minute window to send invs to us.
     *
     * Decreasing the false positive rate is fairly cheap, so we pick one in a
     * million to make it highly unlikely for users to have issues with this
     * filter.
     *
     * We typically only add wtxids to this filter. For non-segwit
     * transactions, the txid == wtxid, so this only prevents us from
     * re-downloading non-segwit transactions when communicating with
     * non-wtxidrelay peers -- which is important for avoiding malleation
     * attacks that could otherwise interfere with transaction relay from
     * non-wtxidrelay peers. For communicating with wtxidrelay peers, having
     * the reject filter store wtxids is exactly what we want to avoid
     * redownload of a rejected transaction.
     *
     * In cases where we can tell that a segwit transaction will fail
     * validation no matter the witness, we may add the txid of such
     * transaction to the filter as well. This can be helpful when
     * communicating with txid-relay peers or if we were to otherwise fetch a
     * transaction via txid (eg in our orphan handling).
     *
     * Memory used: 1.3 MB
     */
    std::unique_ptr<CRollingBloomFilter> m_lazy_recent_rejects{nullptr};

    CRollingBloomFilter& RecentRejectsFilter()
    {
        if (!m_lazy_recent_rejects) {
            m_lazy_recent_rejects = std::make_unique<CRollingBloomFilter>(120'000, 0.000'001);
        }

        return *m_lazy_recent_rejects;
    }

    /**
     * Filter for:
     * (1) wtxids of transactions that were recently rejected by the mempool but are
     * eligible for reconsideration if submitted with other transactions.
     * (2) packages (see GetPackageHash) we have already rejected before and should not retry.
     *
     * Similar to m_lazy_recent_rejects, this filter is used to save bandwidth when e.g. all of our peers
     * have larger mempools and thus lower minimum feerates than us.
     *
     * When a transaction's error is TxValidationResult::TX_RECONSIDERABLE (in a package or by
     * itself), add its wtxid to this filter. When a package fails for any reason, add the combined
     * hash to this filter.
     *
     * Upon receiving an announcement for a transaction, if it exists in this filter, do not
     * download the txdata. When considering packages, if it exists in this filter, drop it.
     *
     * Reset this filter when the chain tip changes.
     *
     * Parameters are picked to be the same as m_lazy_recent_rejects, with the same rationale.
     */
    std::unique_ptr<CRollingBloomFilter> m_lazy_recent_rejects_reconsiderable{nullptr};

    CRollingBloomFilter& RecentRejectsReconsiderableFilter()
    {
        if (!m_lazy_recent_rejects_reconsiderable) {
            m_lazy_recent_rejects_reconsiderable = std::make_unique<CRollingBloomFilter>(120'000, 0.000'001);
        }

        return *m_lazy_recent_rejects_reconsiderable;
    }

    /*
     * Filter for transactions that have been recently confirmed.
     * We use this to avoid requesting transactions that have already been
     * confirmed.
     *
     * Blocks don't typically have more than 4000 transactions, so this should
     * be at least six blocks (~1 hr) worth of transactions that we can store,
     * inserting both a txid and wtxid for every observed transaction.
     * If the number of transactions appearing in a block goes up, or if we are
     * seeing getdata requests more than an hour after initial announcement, we
     * can increase this number.
     * The false positive rate of 1/1M should come out to less than 1
     * transaction per day that would be inadvertently ignored (which is the
     * same probability that we have in the reject filter).
     */
    std::unique_ptr<CRollingBloomFilter> m_lazy_recent_confirmed_transactions{nullptr};

    CRollingBloomFilter& RecentConfirmedTransactionsFilter()
    {
        if (!m_lazy_recent_confirmed_transactions) {
            m_lazy_recent_confirmed_transactions = std::make_unique<CRollingBloomFilter>(48'000, 0.000'001);
        }

        return *m_lazy_recent_confirmed_transactions;
    }

    TxDownloadManagerImpl(const TxDownloadOptions& options) : m_opts{options}, m_txrequest{options.m_deterministic_txrequest} {}

    struct PeerInfo {
        /** Information relevant to scheduling tx requests. */
        const TxDownloadConnectionInfo m_connection_info;

        PeerInfo(const TxDownloadConnectionInfo& info) : m_connection_info{info} {}
    };

    /** Information for all of the peers we may download transactions from. This is not necessarily
     * all peers we are connected to (no block-relay-only and temporary connections). */
    std::map<NodeId, PeerInfo> m_peer_info;

    /** Number of wtxid relay peers we have in m_peer_info. */
    uint32_t m_num_wtxid_peers{0};

    void ActiveTipChange();
    void BlockConnected(const std::shared_ptr<const CBlock>& pblock);
    void BlockDisconnected();

    /** Check whether we already have this gtxid in:
     *  - mempool
     *  - orphanage
     *  - m_recent_rejects
     *  - m_recent_rejects_reconsiderable (if include_reconsiderable = true)
     *  - m_recent_confirmed_transactions
     *  */
    bool AlreadyHaveTx(const GenTxid& gtxid, bool include_reconsiderable);

    void ConnectedPeer(NodeId nodeid, const TxDownloadConnectionInfo& info);
    void DisconnectedPeer(NodeId nodeid);

    /** Consider adding this tx hash to txrequest. Should be called whenever a new inv has been received.
     * Also called internally when a transaction is missing parents so that we can request them.
     */
    bool AddTxAnnouncement(NodeId peer, const GenTxid& gtxid, std::chrono::microseconds now);

    /** Get getdata requests to send. */
    std::vector<GenTxid> GetRequestsToSend(NodeId nodeid, std::chrono::microseconds current_time);

    /** Marks a tx as ReceivedResponse in txrequest. */
    void ReceivedNotFound(NodeId nodeid, const std::vector<uint256>& txhashes);

    /** Look for a child of this transaction in the orphanage to form a 1-parent-1-child package,
     * skipping any combinations that have already been tried. Return the resulting package along with
     * the senders of its respective transactions, or std::nullopt if no package is found. */
    std::optional<PackageToValidate> Find1P1CPackage(const CTransactionRef& ptx, NodeId nodeid);

    void MempoolAcceptedTx(const CTransactionRef& tx);
    RejectedTxTodo MempoolRejectedTx(const CTransactionRef& ptx, const TxValidationState& state, NodeId nodeid, bool first_time_failure);
    void MempoolRejectedPackage(const Package& package);

    std::pair<bool, std::optional<PackageToValidate>> ReceivedTx(NodeId nodeid, const CTransactionRef& ptx);

    bool HaveMoreWork(NodeId nodeid);
    CTransactionRef GetTxToReconsider(NodeId nodeid);

    void CheckIsEmpty();
    void CheckIsEmpty(NodeId nodeid);

    std::vector<TxOrphanage::OrphanTxBase> GetOrphanTransactions() const;

protected:
    /** Helper for getting deduplicated vector of Txids in vin. */
    std::vector<Txid> GetUniqueParents(const CTransaction& tx);

    /** If this peer is an orphan resolution candidate for this transaction, treat the unique_parents as announced by
     * this peer; add them as new invs to m_txrequest.
     * @returns whether this transaction was a valid orphan resolution candidate.
     * */
    bool MaybeAddOrphanResolutionCandidate(const std::vector<Txid>& unique_parents, const Wtxid& wtxid, NodeId nodeid, std::chrono::microseconds now);
};
} // namespace node
#endif // BITCOIN_NODE_TXDOWNLOADMAN_IMPL_H

Coverage Report

Created: 2025-02-21 14:37

Line	Count	Source (jump to first uncovered line)
1		// Copyright (c) 2024
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 <primitives/transaction.h>
14		#include <policy/packages.h>
15		#include <txorphanage.h>
16		#include <txrequest.h>
17
18		class CTxMemPool;
19		namespace node {
20		class TxDownloadManagerImpl {
21		public:
22		TxDownloadOptions m_opts;
23
24		/** Manages unvalidated tx data (orphan transactions for which we are downloading ancestors). */
25		TxOrphanage m_orphanage;
26		/** Tracks candidates for requesting and downloading transaction data. */
27		TxRequestTracker m_txrequest;
28
29		/**
30		* Filter for transactions that were recently rejected by the mempool.
31		* These are not rerequested until the chain tip changes, at which point
32		* the entire filter is reset.
33		*
34		* Without this filter we'd be re-requesting txs from each of our peers,
35		* increasing bandwidth consumption considerably. For instance, with 100
36		* peers, half of which relay a tx we don't accept, that might be a 50x
37		* bandwidth increase. A flooding attacker attempting to roll-over the
38		* filter using minimum-sized, 60byte, transactions might manage to send
39		* 1000/sec if we have fast peers, so we pick 120,000 to give our peers a
40		* two minute window to send invs to us.
41		*
42		* Decreasing the false positive rate is fairly cheap, so we pick one in a
43		* million to make it highly unlikely for users to have issues with this
44		* filter.
45		*
46		* We typically only add wtxids to this filter. For non-segwit
47		* transactions, the txid == wtxid, so this only prevents us from
48		* re-downloading non-segwit transactions when communicating with
49		* non-wtxidrelay peers -- which is important for avoiding malleation
50		* attacks that could otherwise interfere with transaction relay from
51		* non-wtxidrelay peers. For communicating with wtxidrelay peers, having
52		* the reject filter store wtxids is exactly what we want to avoid
53		* redownload of a rejected transaction.
54		*
55		* In cases where we can tell that a segwit transaction will fail
56		* validation no matter the witness, we may add the txid of such
57		* transaction to the filter as well. This can be helpful when
58		* communicating with txid-relay peers or if we were to otherwise fetch a
59		* transaction via txid (eg in our orphan handling).
60		*
61		* Memory used: 1.3 MB
62		*/
63		std::unique_ptr<CRollingBloomFilter> m_lazy_recent_rejects{nullptr};
64
65		CRollingBloomFilter& RecentRejectsFilter()
66	0	{
67	0	if (!m_lazy_recent_rejects) {
68	0	m_lazy_recent_rejects = std::make_unique<CRollingBloomFilter>(120'000, 0.000'001);
69	0	}
70
71	0	return *m_lazy_recent_rejects;
72	0	}
73
74		/**
75		* Filter for:
76		* (1) wtxids of transactions that were recently rejected by the mempool but are
77		* eligible for reconsideration if submitted with other transactions.
78		* (2) packages (see GetPackageHash) we have already rejected before and should not retry.
79		*
80		* Similar to m_lazy_recent_rejects, this filter is used to save bandwidth when e.g. all of our peers
81		* have larger mempools and thus lower minimum feerates than us.
82		*
83		* When a transaction's error is TxValidationResult::TX_RECONSIDERABLE (in a package or by
84		* itself), add its wtxid to this filter. When a package fails for any reason, add the combined
85		* hash to this filter.
86		*
87		* Upon receiving an announcement for a transaction, if it exists in this filter, do not
88		* download the txdata. When considering packages, if it exists in this filter, drop it.
89		*
90		* Reset this filter when the chain tip changes.
91		*
92		* Parameters are picked to be the same as m_lazy_recent_rejects, with the same rationale.
93		*/
94		std::unique_ptr<CRollingBloomFilter> m_lazy_recent_rejects_reconsiderable{nullptr};
95
96		CRollingBloomFilter& RecentRejectsReconsiderableFilter()
97	0	{
98	0	if (!m_lazy_recent_rejects_reconsiderable) {
99	0	m_lazy_recent_rejects_reconsiderable = std::make_unique<CRollingBloomFilter>(120'000, 0.000'001);
100	0	}
101
102	0	return *m_lazy_recent_rejects_reconsiderable;
103	0	}
104
105		/*
106		* Filter for transactions that have been recently confirmed.
107		* We use this to avoid requesting transactions that have already been
108		* confirmed.
109		*
110		* Blocks don't typically have more than 4000 transactions, so this should
111		* be at least six blocks (~1 hr) worth of transactions that we can store,
112		* inserting both a txid and wtxid for every observed transaction.
113		* If the number of transactions appearing in a block goes up, or if we are
114		* seeing getdata requests more than an hour after initial announcement, we
115		* can increase this number.
116		* The false positive rate of 1/1M should come out to less than 1
117		* transaction per day that would be inadvertently ignored (which is the
118		* same probability that we have in the reject filter).
119		*/
120		std::unique_ptr<CRollingBloomFilter> m_lazy_recent_confirmed_transactions{nullptr};
121
122		CRollingBloomFilter& RecentConfirmedTransactionsFilter()
123	0	{
124	0	if (!m_lazy_recent_confirmed_transactions) {
125	0	m_lazy_recent_confirmed_transactions = std::make_unique<CRollingBloomFilter>(48'000, 0.000'001);
126	0	}
127
128	0	return *m_lazy_recent_confirmed_transactions;
129	0	}
130
131	0	TxDownloadManagerImpl(const TxDownloadOptions& options) : m_opts{options}, m_txrequest{options.m_deterministic_txrequest} {}
132
133		struct PeerInfo {
134		/** Information relevant to scheduling tx requests. */
135		const TxDownloadConnectionInfo m_connection_info;
136
137	0	PeerInfo(const TxDownloadConnectionInfo& info) : m_connection_info{info} {}
138		};
139
140		/** Information for all of the peers we may download transactions from. This is not necessarily
141		* all peers we are connected to (no block-relay-only and temporary connections). */
142		std::map<NodeId, PeerInfo> m_peer_info;
143
144		/** Number of wtxid relay peers we have in m_peer_info. */
145		uint32_t m_num_wtxid_peers{0};
146
147		void ActiveTipChange();
148		void BlockConnected(const std::shared_ptr<const CBlock>& pblock);
149		void BlockDisconnected();
150
151		/** Check whether we already have this gtxid in:
152		* - mempool
153		* - orphanage
154		* - m_recent_rejects
155		* - m_recent_rejects_reconsiderable (if include_reconsiderable = true)
156		* - m_recent_confirmed_transactions
157		* */
158		bool AlreadyHaveTx(const GenTxid& gtxid, bool include_reconsiderable);
159
160		void ConnectedPeer(NodeId nodeid, const TxDownloadConnectionInfo& info);
161		void DisconnectedPeer(NodeId nodeid);
162
163		/** Consider adding this tx hash to txrequest. Should be called whenever a new inv has been received.
164		* Also called internally when a transaction is missing parents so that we can request them.
165		*/
166		bool AddTxAnnouncement(NodeId peer, const GenTxid& gtxid, std::chrono::microseconds now);
167
168		/** Get getdata requests to send. */
169		std::vector<GenTxid> GetRequestsToSend(NodeId nodeid, std::chrono::microseconds current_time);
170
171		/** Marks a tx as ReceivedResponse in txrequest. */
172		void ReceivedNotFound(NodeId nodeid, const std::vector<uint256>& txhashes);
173
174		/** Look for a child of this transaction in the orphanage to form a 1-parent-1-child package,
175		* skipping any combinations that have already been tried. Return the resulting package along with
176		* the senders of its respective transactions, or std::nullopt if no package is found. */
177		std::optional<PackageToValidate> Find1P1CPackage(const CTransactionRef& ptx, NodeId nodeid);
178
179		void MempoolAcceptedTx(const CTransactionRef& tx);
180		RejectedTxTodo MempoolRejectedTx(const CTransactionRef& ptx, const TxValidationState& state, NodeId nodeid, bool first_time_failure);
181		void MempoolRejectedPackage(const Package& package);
182
183		std::pair<bool, std::optional<PackageToValidate>> ReceivedTx(NodeId nodeid, const CTransactionRef& ptx);
184
185		bool HaveMoreWork(NodeId nodeid);
186		CTransactionRef GetTxToReconsider(NodeId nodeid);
187
188		void CheckIsEmpty();
189		void CheckIsEmpty(NodeId nodeid);
190
191		std::vector<TxOrphanage::OrphanTxBase> GetOrphanTransactions() const;
192
193		protected:
194		/** Helper for getting deduplicated vector of Txids in vin. */
195		std::vector<Txid> GetUniqueParents(const CTransaction& tx);
196
197		/** If this peer is an orphan resolution candidate for this transaction, treat the unique_parents as announced by
198		* this peer; add them as new invs to m_txrequest.
199		* @returns whether this transaction was a valid orphan resolution candidate.
200		* */
201		bool MaybeAddOrphanResolutionCandidate(const std::vector<Txid>& unique_parents, const Wtxid& wtxid, NodeId nodeid, std::chrono::microseconds now);
202		};
203		} // namespace node
204		#endif // BITCOIN_NODE_TXDOWNLOADMAN_IMPL_H