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 5 #ifndef BITCOIN_NODE_TXDOWNLOADMAN_H
6 #define BITCOIN_NODE_TXDOWNLOADMAN_H
7 8 #include <net.h>
9 #include <node/txorphanage.h>
10 #include <policy/packages.h>
11 12 #include <cstdint>
13 #include <memory>
14 15 class CBlock;
16 class CRollingBloomFilter;
17 class CTxMemPool;
18 class GenTxid;
19 class TxRequestTracker;
20 namespace node {
21 class TxDownloadManagerImpl;
22 23 /** Maximum number of in-flight transaction requests from a peer. It is not a hard limit, but the threshold at which
24 * point the OVERLOADED_PEER_TX_DELAY kicks in. */
25 static constexpr int32_t MAX_PEER_TX_REQUEST_IN_FLIGHT = 100;
26 /** Maximum number of transactions to consider for requesting, per peer. It provides a reasonable DoS limit to
27 * per-peer memory usage spent on announcements, while covering peers continuously sending INVs at the maximum
28 * rate (by our own policy, see INVENTORY_BROADCAST_PER_SECOND) for several minutes, while not receiving
29 * the actual transaction (from any peer) in response to requests for them. */
30 static constexpr int32_t MAX_PEER_TX_ANNOUNCEMENTS = 5000;
31 /** How long to delay requesting transactions via txids, if we have wtxid-relaying peers */
32 static constexpr auto TXID_RELAY_DELAY{2s};
33 /** How long to delay requesting transactions from non-preferred peers */
34 static constexpr auto NONPREF_PEER_TX_DELAY{2s};
35 /** How long to delay requesting transactions from overloaded peers (see MAX_PEER_TX_REQUEST_IN_FLIGHT). */
36 static constexpr auto OVERLOADED_PEER_TX_DELAY{2s};
37 /** How long to wait before downloading a transaction from an additional peer */
38 static constexpr auto GETDATA_TX_INTERVAL{60s};
39 struct TxDownloadOptions {
40 /** Read-only reference to mempool. */
41 const CTxMemPool& m_mempool;
42 /** RNG provided by caller. */
43 FastRandomContext& m_rng;
44 /** Instantiate TxRequestTracker as deterministic (used for tests). */
45 bool m_deterministic_txrequest{false};
46 };
47 struct TxDownloadConnectionInfo {
48 /** Whether this peer is preferred for transaction download. */
49 const bool m_preferred;
50 /** Whether this peer has Relay permissions. */
51 const bool m_relay_permissions;
52 /** Whether this peer supports wtxid relay. */
53 const bool m_wtxid_relay;
54 };
55 struct PackageToValidate {
56 Package m_txns;
57 std::vector<NodeId> m_senders;
58 /** Construct a 1-parent-1-child package. */
59 explicit PackageToValidate(const CTransactionRef& parent,
60 const CTransactionRef& child,
61 NodeId parent_sender,
62 NodeId child_sender) :
63 m_txns{parent, child},
64 m_senders{parent_sender, child_sender}
65 {}
66 67 // Move ctor
68 PackageToValidate(PackageToValidate&& other) : m_txns{std::move(other.m_txns)}, m_senders{std::move(other.m_senders)} {}
69 // Copy ctor
70 PackageToValidate(const PackageToValidate& other) = default;
71 72 // Move assignment
73 PackageToValidate& operator=(PackageToValidate&& other) {
74 this->m_txns = std::move(other.m_txns);
75 this->m_senders = std::move(other.m_senders);
76 return *this;
77 }
78 79 std::string ToString() const {
80 Assume(m_txns.size() == 2);
81 return strprintf("parent %s (wtxid=%s, sender=%d) + child %s (wtxid=%s, sender=%d)",
82 m_txns.front()->GetHash().ToString(),
83 m_txns.front()->GetWitnessHash().ToString(),
84 m_senders.front(),
85 m_txns.back()->GetHash().ToString(),
86 m_txns.back()->GetWitnessHash().ToString(),
87 m_senders.back());
88 }
89 };
90 struct RejectedTxTodo
91 {
92 bool m_should_add_extra_compact_tx;
93 std::vector<Txid> m_unique_parents;
94 std::optional<PackageToValidate> m_package_to_validate;
95 };
96 97 98 /**
99 * Class responsible for deciding what transactions to request and, once
100 * downloaded, whether and how to validate them. It is also responsible for
101 * deciding what transaction packages to validate and how to resolve orphan
102 * transactions. Its data structures include TxRequestTracker for scheduling
103 * requests, rolling bloom filters for remembering transactions that have
104 * already been {accepted, rejected, confirmed}, an orphanage, and a registry of
105 * each peer's transaction relay-related information.
106 *
107 * Caller needs to interact with TxDownloadManager:
108 * - ValidationInterface callbacks.
109 * - When a potential transaction relay peer connects or disconnects.
110 * - When a transaction or package is accepted or rejected from mempool
111 * - When a inv, notfound, or tx message is received
112 * - To get instructions for which getdata messages to send
113 *
114 * This class is not thread-safe. Access must be synchronized using an
115 * external mutex.
116 */
117 class TxDownloadManager {
118 const std::unique_ptr<TxDownloadManagerImpl> m_impl;
119 120 public:
121 explicit TxDownloadManager(const TxDownloadOptions& options);
122 ~TxDownloadManager();
123 124 // Responses to chain events. TxDownloadManager is not an actual client of ValidationInterface, these are called through PeerManager.
125 void ActiveTipChange();
126 void BlockConnected(const std::shared_ptr<const CBlock>& pblock);
127 void BlockDisconnected();
128 129 /** Creates a new PeerInfo. Saves the connection info to calculate tx announcement delays later. */
130 void ConnectedPeer(NodeId nodeid, const TxDownloadConnectionInfo& info);
131 132 /** Deletes all txrequest announcements and orphans for a given peer. */
133 void DisconnectedPeer(NodeId nodeid);
134 135 /** Consider adding this tx hash to txrequest. Should be called whenever a new inv has been received.
136 * Also called internally when a transaction is missing parents so that we can request them.
137 * Returns true if this was a dropped inv (p2p_inv=true and we already have the tx), false otherwise. */
138 bool AddTxAnnouncement(NodeId peer, const GenTxid& gtxid, std::chrono::microseconds now);
139 140 /** Get getdata requests to send. */
141 std::vector<GenTxid> GetRequestsToSend(NodeId nodeid, std::chrono::microseconds current_time);
142 143 /** Should be called when a notfound for a tx has been received. */
144 void ReceivedNotFound(NodeId nodeid, const std::vector<GenTxid>& gtxids);
145 146 /** Respond to successful transaction submission to mempool */
147 void MempoolAcceptedTx(const CTransactionRef& tx);
148 149 /** Respond to transaction rejected from mempool */
150 RejectedTxTodo MempoolRejectedTx(const CTransactionRef& ptx, const TxValidationState& state, NodeId nodeid, bool first_time_failure);
151 152 /** Respond to package rejected from mempool */
153 void MempoolRejectedPackage(const Package& package);
154 155 /** Marks a tx as ReceivedResponse in txrequest and checks whether AlreadyHaveTx.
156 * Return a bool indicating whether this tx should be validated. If false, optionally, a
157 * PackageToValidate. */
158 std::pair<bool, std::optional<PackageToValidate>> ReceivedTx(NodeId nodeid, const CTransactionRef& ptx);
159 160 /** Whether there are any orphans to reconsider for this peer. */
161 bool HaveMoreWork(NodeId nodeid) const;
162 163 /** Returns next orphan tx to consider, or nullptr if none exist. */
164 CTransactionRef GetTxToReconsider(NodeId nodeid);
165 166 /** Check that all data structures are empty. */
167 void CheckIsEmpty() const;
168 169 /** Check that all data structures that track per-peer information have nothing for this peer. */
170 void CheckIsEmpty(NodeId nodeid) const;
171 172 /** Wrapper for TxOrphanage::GetOrphanTransactions */
173 std::vector<TxOrphanage::OrphanInfo> GetOrphanTransactions() const;
174 };
175 } // namespace node
176 #endif // BITCOIN_NODE_TXDOWNLOADMAN_H
177