/tmp/bitcoin/src/private_broadcast.h

Source
// Copyright (c) 2023-present The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or https://opensource.org/license/mit/.

#ifndef BITCOIN_PRIVATE_BROADCAST_H
#define BITCOIN_PRIVATE_BROADCAST_H

#include <net.h>
#include <primitives/transaction.h>
#include <primitives/transaction_identifier.h>
#include <sync.h>
#include <util/time.h>

#include <optional>
#include <tuple>
#include <unordered_map>
#include <vector>

/**
 * Store a list of transactions to be broadcast privately. Supports the following operations:
 * - Add a new transaction
 * - Remove a transaction
 * - Pick a transaction for sending to one recipient
 * - Query which transaction has been picked for sending to a given recipient node
 * - Mark that a given recipient node has confirmed receipt of a transaction
 * - Query whether a given recipient node has confirmed reception
 * - Query whether any transactions that need sending are currently on the list
 */
class PrivateBroadcast
{
public:

    /// If a transaction is not sent to any peer for this duration,
    /// then we consider it stale / for rebroadcasting.
    static constexpr auto INITIAL_STALE_DURATION{5min};

    /// If a transaction is not received back from the network for this duration
    /// after it is broadcast, then we consider it stale / for rebroadcasting.
    static constexpr auto STALE_DURATION{1min};

    struct PeerSendInfo {
        CService address;
        NodeClock::time_point sent;
        std::optional<NodeClock::time_point> received;
    };

    struct TxBroadcastInfo {
        CTransactionRef tx;
        NodeClock::time_point time_added;
        std::vector<PeerSendInfo> peers;
    };

    /**
     * Add a transaction to the storage.
     * @param[in] tx The transaction to add.
     * @retval true The transaction was added.
     * @retval false The transaction was already present.
     */
    bool Add(const CTransactionRef& tx)
        EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);

    /**
     * Forget a transaction.
     * @param[in] tx Transaction to forget.
     * @retval !nullopt The number of times the transaction was sent and confirmed
     * by the recipient (if the transaction existed and was removed).
     * @retval nullopt The transaction was not in the storage.
     */
    std::optional<size_t> Remove(const CTransactionRef& tx)
        EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);

    /**
     * Pick the transaction with the fewest send attempts, and confirmations,
     * and oldest send/confirm times.
     * @param[in] will_send_to_nodeid Will remember that the returned transaction
     * was picked for sending to this node.
     * @param[in] will_send_to_address Address of the peer to which this transaction
     * will be sent.
     * @return Most urgent transaction or nullopt if there are no transactions.
     */
    std::optional<CTransactionRef> PickTxForSend(const NodeId& will_send_to_nodeid, const CService& will_send_to_address)
        EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);

    /**
     * Get the transaction that was picked for sending to a given node by PickTxForSend().
     * @param[in] nodeid Node to which a transaction is being (or was) sent.
     * @return Transaction or nullopt if the nodeid is unknown.
     */
    std::optional<CTransactionRef> GetTxForNode(const NodeId& nodeid)
        EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);

    /**
     * Mark that the node has confirmed reception of the transaction we sent it by
     * responding with `PONG` to our `PING` message.
     * @param[in] nodeid Node that we sent a transaction to.
     */
    void NodeConfirmedReception(const NodeId& nodeid)
        EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);

    /**
     * Check if the node has confirmed reception of the transaction.
     * @retval true Node has confirmed, `NodeConfirmedReception()` has been called.
     * @retval false Node has not confirmed, `NodeConfirmedReception()` has not been called.
     */
    bool DidNodeConfirmReception(const NodeId& nodeid)
        EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);

    /**
     * Check if there are transactions that need to be broadcast.
     */
    bool HavePendingTransactions()
        EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);

    /**
     * Get the transactions that have not been broadcast recently.
     */
    std::vector<CTransactionRef> GetStale() const
        EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);

    /**
     * Get stats about all transactions currently being privately broadcast.
     */
    std::vector<TxBroadcastInfo> GetBroadcastInfo() const
        EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);

private:
    /// Status of a transaction sent to a given node.
    struct SendStatus {
        /// Node to which the transaction will be sent (or was sent).
        const NodeId nodeid;
        /// Address of the node.
        const CService address;
        /// When was the transaction picked for sending to the node.
        const NodeClock::time_point picked;
        /// When was the transaction reception confirmed by the node (by PONG).
        std::optional<NodeClock::time_point> confirmed;

        SendStatus(const NodeId& nodeid, const CService& address, const NodeClock::time_point& picked) : nodeid{nodeid}, address{address}, picked{picked} {}
    };

    /// Cumulative stats from all the send attempts for a transaction. Used to prioritize transactions.
    struct Priority {
        size_t num_picked{0}; ///< Number of times the transaction was picked for sending.
        NodeClock::time_point last_picked{}; ///< The most recent time when the transaction was picked for sending.
        size_t num_confirmed{0}; ///< Number of nodes that have confirmed reception of a transaction (by PONG).
        NodeClock::time_point last_confirmed{}; ///< The most recent time when the transaction was confirmed.

        auto operator<=>(const Priority& other) const
        {
            // Invert `other` and `this` in the comparison because smaller num_picked, num_confirmed or
            // earlier times mean greater priority. In other words, if this.num_picked < other.num_picked
            // then this > other.
            return std::tie(other.num_picked, other.num_confirmed, other.last_picked, other.last_confirmed) <=>
                   std::tie(num_picked, num_confirmed, last_picked, last_confirmed);
        }
    };

    /// A pair of a transaction and a sent status for a given node. Convenience return type of GetSendStatusByNode().
    struct TxAndSendStatusForNode {
        const CTransactionRef& tx;
        SendStatus& send_status;
    };

    // No need for salted hasher because we are going to store just a bunch of locally originating transactions.

    struct CTransactionRefHash {
        size_t operator()(const CTransactionRef& tx) const
        {
            return static_cast<size_t>(tx->GetWitnessHash().ToUint256().GetUint64(0));
        }
    };

    struct CTransactionRefComp {
        bool operator()(const CTransactionRef& a, const CTransactionRef& b) const
        {
            return a->GetWitnessHash() == b->GetWitnessHash(); // If wtxid equals, then txid also equals.
        }
    };

    /**
     * Derive the sending priority of a transaction.
     * @param[in] sent_to List of nodes that the transaction has been sent to.
     */
    static Priority DerivePriority(const std::vector<SendStatus>& sent_to);

    /**
     * Find which transaction we sent to a given node (marked by PickTxForSend()).
     * @return That transaction together with the send status or nullopt if we did not
     * send any transaction to the given node.
     */
    std::optional<TxAndSendStatusForNode> GetSendStatusByNode(const NodeId& nodeid)
        EXCLUSIVE_LOCKS_REQUIRED(m_mutex);
    struct TxSendStatus {
        const NodeClock::time_point time_added{NodeClock::now()};
        std::vector<SendStatus> send_statuses;
    };
    mutable Mutex m_mutex;
    std::unordered_map<CTransactionRef, TxSendStatus, CTransactionRefHash, CTransactionRefComp>
        m_transactions GUARDED_BY(m_mutex);
};

#endif // BITCOIN_PRIVATE_BROADCAST_H

Coverage Report

Created: 2026-04-29 19:21

Line	Count	Source
1		// Copyright (c) 2023-present The Bitcoin Core developers
2		// Distributed under the MIT software license, see the accompanying
3		// file COPYING or https://opensource.org/license/mit/.
4
5		#ifndef BITCOIN_PRIVATE_BROADCAST_H
6		#define BITCOIN_PRIVATE_BROADCAST_H
7
8		#include <net.h>
9		#include <primitives/transaction.h>
10		#include <primitives/transaction_identifier.h>
11		#include <sync.h>
12		#include <util/time.h>
13
14		#include <optional>
15		#include <tuple>
16		#include <unordered_map>
17		#include <vector>
18
19		/**
20		* Store a list of transactions to be broadcast privately. Supports the following operations:
21		* - Add a new transaction
22		* - Remove a transaction
23		* - Pick a transaction for sending to one recipient
24		* - Query which transaction has been picked for sending to a given recipient node
25		* - Mark that a given recipient node has confirmed receipt of a transaction
26		* - Query whether a given recipient node has confirmed reception
27		* - Query whether any transactions that need sending are currently on the list
28		*/
29		class PrivateBroadcast
30		{
31		public:
32
33		/// If a transaction is not sent to any peer for this duration,
34		/// then we consider it stale / for rebroadcasting.
35		static constexpr auto INITIAL_STALE_DURATION{5min};
36
37		/// If a transaction is not received back from the network for this duration
38		/// after it is broadcast, then we consider it stale / for rebroadcasting.
39		static constexpr auto STALE_DURATION{1min};
40
41		struct PeerSendInfo {
42		CService address;
43		NodeClock::time_point sent;
44		std::optional<NodeClock::time_point> received;
45		};
46
47		struct TxBroadcastInfo {
48		CTransactionRef tx;
49		NodeClock::time_point time_added;
50		std::vector<PeerSendInfo> peers;
51		};
52
53		/**
54		* Add a transaction to the storage.
55		* @param[in] tx The transaction to add.
56		* @retval true The transaction was added.
57		* @retval false The transaction was already present.
58		*/
59		bool Add(const CTransactionRef& tx)
60		EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
61
62		/**
63		* Forget a transaction.
64		* @param[in] tx Transaction to forget.
65		* @retval !nullopt The number of times the transaction was sent and confirmed
66		* by the recipient (if the transaction existed and was removed).
67		* @retval nullopt The transaction was not in the storage.
68		*/
69		std::optional<size_t> Remove(const CTransactionRef& tx)
70		EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
71
72		/**
73		* Pick the transaction with the fewest send attempts, and confirmations,
74		* and oldest send/confirm times.
75		* @param[in] will_send_to_nodeid Will remember that the returned transaction
76		* was picked for sending to this node.
77		* @param[in] will_send_to_address Address of the peer to which this transaction
78		* will be sent.
79		* @return Most urgent transaction or nullopt if there are no transactions.
80		*/
81		std::optional<CTransactionRef> PickTxForSend(const NodeId& will_send_to_nodeid, const CService& will_send_to_address)
82		EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
83
84		/**
85		* Get the transaction that was picked for sending to a given node by PickTxForSend().
86		* @param[in] nodeid Node to which a transaction is being (or was) sent.
87		* @return Transaction or nullopt if the nodeid is unknown.
88		*/
89		std::optional<CTransactionRef> GetTxForNode(const NodeId& nodeid)
90		EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
91
92		/**
93		* Mark that the node has confirmed reception of the transaction we sent it by
94		* responding with `PONG` to our `PING` message.
95		* @param[in] nodeid Node that we sent a transaction to.
96		*/
97		void NodeConfirmedReception(const NodeId& nodeid)
98		EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
99
100		/**
101		* Check if the node has confirmed reception of the transaction.
102		* @retval true Node has confirmed, `NodeConfirmedReception()` has been called.
103		* @retval false Node has not confirmed, `NodeConfirmedReception()` has not been called.
104		*/
105		bool DidNodeConfirmReception(const NodeId& nodeid)
106		EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
107
108		/**
109		* Check if there are transactions that need to be broadcast.
110		*/
111		bool HavePendingTransactions()
112		EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
113
114		/**
115		* Get the transactions that have not been broadcast recently.
116		*/
117		std::vector<CTransactionRef> GetStale() const
118		EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
119
120		/**
121		* Get stats about all transactions currently being privately broadcast.
122		*/
123		std::vector<TxBroadcastInfo> GetBroadcastInfo() const
124		EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
125
126		private:
127		/// Status of a transaction sent to a given node.
128		struct SendStatus {
129		/// Node to which the transaction will be sent (or was sent).
130		const NodeId nodeid;
131		/// Address of the node.
132		const CService address;
133		/// When was the transaction picked for sending to the node.
134		const NodeClock::time_point picked;
135		/// When was the transaction reception confirmed by the node (by PONG).
136		std::optional<NodeClock::time_point> confirmed;
137
138	12	SendStatus(const NodeId& nodeid, const CService& address, const NodeClock::time_point& picked) : nodeid{nodeid}, address{address}, picked{picked} {}
139		};
140
141		/// Cumulative stats from all the send attempts for a transaction. Used to prioritize transactions.
142		struct Priority {
143		size_t num_picked{0}; ///< Number of times the transaction was picked for sending.
144		NodeClock::time_point last_picked{}; ///< The most recent time when the transaction was picked for sending.
145		size_t num_confirmed{0}; ///< Number of nodes that have confirmed reception of a transaction (by PONG).
146		NodeClock::time_point last_confirmed{}; ///< The most recent time when the transaction was confirmed.
147
148		auto operator<=>(const Priority& other) const
149	5	{
150		// Invert `other` and `this` in the comparison because smaller num_picked, num_confirmed or
151		// earlier times mean greater priority. In other words, if this.num_picked < other.num_picked
152		// then this > other.
153	5	return std::tie(other.num_picked, other.num_confirmed, other.last_picked, other.last_confirmed) <=>
154	5	std::tie(num_picked, num_confirmed, last_picked, last_confirmed);
155	5	}
156		};
157
158		/// A pair of a transaction and a sent status for a given node. Convenience return type of GetSendStatusByNode().
159		struct TxAndSendStatusForNode {
160		const CTransactionRef& tx;
161		SendStatus& send_status;
162		};
163
164		// No need for salted hasher because we are going to store just a bunch of locally originating transactions.
165
166		struct CTransactionRefHash {
167		size_t operator()(const CTransactionRef& tx) const
168	16.2k	{
169	16.2k	return static_cast<size_t>(tx->GetWitnessHash().ToUint256().GetUint64(0));
170	16.2k	}
171		};
172
173		struct CTransactionRefComp {
174		bool operator()(const CTransactionRef& a, const CTransactionRef& b) const
175	7	{
176	7	return a->GetWitnessHash() == b->GetWitnessHash(); // If wtxid equals, then txid also equals.
177	7	}
178		};
179
180		/**
181		* Derive the sending priority of a transaction.
182		* @param[in] sent_to List of nodes that the transaction has been sent to.
183		*/
184		static Priority DerivePriority(const std::vector<SendStatus>& sent_to);
185
186		/**
187		* Find which transaction we sent to a given node (marked by PickTxForSend()).
188		* @return That transaction together with the send status or nullopt if we did not
189		* send any transaction to the given node.
190		*/
191		std::optional<TxAndSendStatusForNode> GetSendStatusByNode(const NodeId& nodeid)
192		EXCLUSIVE_LOCKS_REQUIRED(m_mutex);
193		struct TxSendStatus {
194		const NodeClock::time_point time_added{NodeClock::now()};
195		std::vector<SendStatus> send_statuses;
196		};
197		mutable Mutex m_mutex;
198		std::unordered_map<CTransactionRef, TxSendStatus, CTransactionRefHash, CTransactionRefComp>
199		m_transactions GUARDED_BY(m_mutex);
200		};
201
202		#endif // BITCOIN_PRIVATE_BROADCAST_H