chain.h
1 // Copyright (c) 2018-2022 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_INTERFACES_CHAIN_H 6 #define BITCOIN_INTERFACES_CHAIN_H 7 8 #include <blockfilter.h> 9 #include <common/settings.h> 10 #include <primitives/transaction.h> // For CTransactionRef 11 #include <util/result.h> 12 13 #include <functional> 14 #include <memory> 15 #include <optional> 16 #include <stddef.h> 17 #include <stdint.h> 18 #include <string> 19 #include <vector> 20 21 class ArgsManager; 22 class CBlock; 23 class CBlockUndo; 24 class CFeeRate; 25 class CRPCCommand; 26 class CScheduler; 27 class Coin; 28 class uint256; 29 enum class MemPoolRemovalReason; 30 enum class RBFTransactionState; 31 enum class ChainstateRole; 32 struct bilingual_str; 33 struct CBlockLocator; 34 struct FeeCalculation; 35 namespace node { 36 struct NodeContext; 37 } // namespace node 38 39 namespace interfaces { 40 41 class Handler; 42 class Wallet; 43 44 //! Helper for findBlock to selectively return pieces of block data. If block is 45 //! found, data will be returned by setting specified output variables. If block 46 //! is not found, output variables will keep their previous values. 47 class FoundBlock 48 { 49 public: 50 FoundBlock& hash(uint256& hash) { m_hash = &hash; return *this; } 51 FoundBlock& height(int& height) { m_height = &height; return *this; } 52 FoundBlock& time(int64_t& time) { m_time = &time; return *this; } 53 FoundBlock& maxTime(int64_t& max_time) { m_max_time = &max_time; return *this; } 54 FoundBlock& mtpTime(int64_t& mtp_time) { m_mtp_time = &mtp_time; return *this; } 55 //! Return whether block is in the active (most-work) chain. 56 FoundBlock& inActiveChain(bool& in_active_chain) { m_in_active_chain = &in_active_chain; return *this; } 57 //! Return locator if block is in the active chain. 58 FoundBlock& locator(CBlockLocator& locator) { m_locator = &locator; return *this; } 59 //! Return next block in the active chain if current block is in the active chain. 60 FoundBlock& nextBlock(const FoundBlock& next_block) { m_next_block = &next_block; return *this; } 61 //! Read block data from disk. If the block exists but doesn't have data 62 //! (for example due to pruning), the CBlock variable will be set to null. 63 FoundBlock& data(CBlock& data) { m_data = &data; return *this; } 64 65 uint256* m_hash = nullptr; 66 int* m_height = nullptr; 67 int64_t* m_time = nullptr; 68 int64_t* m_max_time = nullptr; 69 int64_t* m_mtp_time = nullptr; 70 bool* m_in_active_chain = nullptr; 71 CBlockLocator* m_locator = nullptr; 72 const FoundBlock* m_next_block = nullptr; 73 CBlock* m_data = nullptr; 74 mutable bool found = false; 75 }; 76 77 //! Block data sent with blockConnected, blockDisconnected notifications. 78 struct BlockInfo { 79 const uint256& hash; 80 const uint256* prev_hash = nullptr; 81 int height = -1; 82 int file_number = -1; 83 unsigned data_pos = 0; 84 const CBlock* data = nullptr; 85 const CBlockUndo* undo_data = nullptr; 86 // The maximum time in the chain up to and including this block. 87 // A timestamp that can only move forward. 88 unsigned int chain_time_max{0}; 89 90 BlockInfo(const uint256& hash LIFETIMEBOUND) : hash(hash) {} 91 }; 92 93 //! The action to be taken after updating a settings value. 94 //! WRITE indicates that the updated value must be written to disk, 95 //! while SKIP_WRITE indicates that the change will be kept in memory-only 96 //! without persisting it. 97 enum class SettingsAction { 98 WRITE, 99 SKIP_WRITE 100 }; 101 102 using SettingsUpdate = std::function<std::optional<interfaces::SettingsAction>(common::SettingsValue&)>; 103 104 //! Interface giving clients (wallet processes, maybe other analysis tools in 105 //! the future) ability to access to the chain state, receive notifications, 106 //! estimate fees, and submit transactions. 107 //! 108 //! TODO: Current chain methods are too low level, exposing too much of the 109 //! internal workings of the bitcoin node, and not being very convenient to use. 110 //! Chain methods should be cleaned up and simplified over time. Examples: 111 //! 112 //! * The initMessages() and showProgress() methods which the wallet uses to send 113 //! notifications to the GUI should go away when GUI and wallet can directly 114 //! communicate with each other without going through the node 115 //! (https://github.com/bitcoin/bitcoin/pull/15288#discussion_r253321096). 116 //! 117 //! * The handleRpc, registerRpcs, rpcEnableDeprecated methods and other RPC 118 //! methods can go away if wallets listen for HTTP requests on their own 119 //! ports instead of registering to handle requests on the node HTTP port. 120 //! 121 //! * Move fee estimation queries to an asynchronous interface and let the 122 //! wallet cache it, fee estimation being driven by node mempool, wallet 123 //! should be the consumer. 124 //! 125 //! * `guessVerificationProgress` and similar methods can go away if rescan 126 //! logic moves out of the wallet, and the wallet just requests scans from the 127 //! node (https://github.com/bitcoin/bitcoin/issues/11756) 128 class Chain 129 { 130 public: 131 virtual ~Chain() = default; 132 133 //! Get current chain height, not including genesis block (returns 0 if 134 //! chain only contains genesis block, nullopt if chain does not contain 135 //! any blocks) 136 virtual std::optional<int> getHeight() = 0; 137 138 //! Get block hash. Height must be valid or this function will abort. 139 virtual uint256 getBlockHash(int height) = 0; 140 141 //! Check that the block is available on disk (i.e. has not been 142 //! pruned), and contains transactions. 143 virtual bool haveBlockOnDisk(int height) = 0; 144 145 //! Get locator for the current chain tip. 146 virtual CBlockLocator getTipLocator() = 0; 147 148 //! Return a locator that refers to a block in the active chain. 149 //! If specified block is not in the active chain, return locator for the latest ancestor that is in the chain. 150 virtual CBlockLocator getActiveChainLocator(const uint256& block_hash) = 0; 151 152 //! Return height of the highest block on chain in common with the locator, 153 //! which will either be the original block used to create the locator, 154 //! or one of its ancestors. 155 virtual std::optional<int> findLocatorFork(const CBlockLocator& locator) = 0; 156 157 //! Returns whether a block filter index is available. 158 virtual bool hasBlockFilterIndex(BlockFilterType filter_type) = 0; 159 160 //! Returns whether any of the elements match the block via a BIP 157 block filter 161 //! or std::nullopt if the block filter for this block couldn't be found. 162 virtual std::optional<bool> blockFilterMatchesAny(BlockFilterType filter_type, const uint256& block_hash, const GCSFilter::ElementSet& filter_set) = 0; 163 164 //! Return whether node has the block and optionally return block metadata 165 //! or contents. 166 virtual bool findBlock(const uint256& hash, const FoundBlock& block={}) = 0; 167 168 //! Find first block in the chain with timestamp >= the given time 169 //! and height >= than the given height, return false if there is no block 170 //! with a high enough timestamp and height. Optionally return block 171 //! information. 172 virtual bool findFirstBlockWithTimeAndHeight(int64_t min_time, int min_height, const FoundBlock& block={}) = 0; 173 174 //! Find ancestor of block at specified height and optionally return 175 //! ancestor information. 176 virtual bool findAncestorByHeight(const uint256& block_hash, int ancestor_height, const FoundBlock& ancestor_out={}) = 0; 177 178 //! Return whether block descends from a specified ancestor, and 179 //! optionally return ancestor information. 180 virtual bool findAncestorByHash(const uint256& block_hash, 181 const uint256& ancestor_hash, 182 const FoundBlock& ancestor_out={}) = 0; 183 184 //! Find most recent common ancestor between two blocks and optionally 185 //! return block information. 186 virtual bool findCommonAncestor(const uint256& block_hash1, 187 const uint256& block_hash2, 188 const FoundBlock& ancestor_out={}, 189 const FoundBlock& block1_out={}, 190 const FoundBlock& block2_out={}) = 0; 191 192 //! Look up unspent output information. Returns coins in the mempool and in 193 //! the current chain UTXO set. Iterates through all the keys in the map and 194 //! populates the values. 195 virtual void findCoins(std::map<COutPoint, Coin>& coins) = 0; 196 197 //! Estimate fraction of total transactions verified if blocks up to 198 //! the specified block hash are verified. 199 virtual double guessVerificationProgress(const uint256& block_hash) = 0; 200 201 //! Return true if data is available for all blocks in the specified range 202 //! of blocks. This checks all blocks that are ancestors of block_hash in 203 //! the height range from min_height to max_height, inclusive. 204 virtual bool hasBlocks(const uint256& block_hash, int min_height = 0, std::optional<int> max_height = {}) = 0; 205 206 //! Check if transaction is RBF opt in. 207 virtual RBFTransactionState isRBFOptIn(const CTransaction& tx) = 0; 208 209 //! Check if transaction is in mempool. 210 virtual bool isInMempool(const uint256& txid) = 0; 211 212 //! Check if transaction has descendants in mempool. 213 virtual bool hasDescendantsInMempool(const uint256& txid) = 0; 214 215 //! Transaction is added to memory pool, if the transaction fee is below the 216 //! amount specified by max_tx_fee, and broadcast to all peers if relay is set to true. 217 //! Return false if the transaction could not be added due to the fee or for another reason. 218 virtual bool broadcastTransaction(const CTransactionRef& tx, 219 const CAmount& max_tx_fee, 220 bool relay, 221 std::string& err_string) = 0; 222 223 //! Calculate mempool ancestor and descendant counts for the given transaction. 224 virtual void getTransactionAncestry(const uint256& txid, size_t& ancestors, size_t& descendants, size_t* ancestorsize = nullptr, CAmount* ancestorfees = nullptr) = 0; 225 226 //! For each outpoint, calculate the fee-bumping cost to spend this outpoint at the specified 227 // feerate, including bumping its ancestors. For example, if the target feerate is 10sat/vbyte 228 // and this outpoint refers to a mempool transaction at 3sat/vbyte, the bump fee includes the 229 // cost to bump the mempool transaction to 10sat/vbyte (i.e. 7 * mempooltx.vsize). If that 230 // transaction also has, say, an unconfirmed parent with a feerate of 1sat/vbyte, the bump fee 231 // includes the cost to bump the parent (i.e. 9 * parentmempooltx.vsize). 232 // 233 // If the outpoint comes from an unconfirmed transaction that is already above the target 234 // feerate or bumped by its descendant(s) already, it does not need to be bumped. Its bump fee 235 // is 0. Likewise, if any of the transaction's ancestors are already bumped by a transaction 236 // in our mempool, they are not included in the transaction's bump fee. 237 // 238 // Also supported is bump-fee calculation in the case of replacements. If an outpoint 239 // conflicts with another transaction in the mempool, it is assumed that the goal is to replace 240 // that transaction. As such, the calculation will exclude the to-be-replaced transaction, but 241 // will include the fee-bumping cost. If bump fees of descendants of the to-be-replaced 242 // transaction are requested, the value will be 0. Fee-related RBF rules are not included as 243 // they are logically distinct. 244 // 245 // Any outpoints that are otherwise unavailable from the mempool (e.g. UTXOs from confirmed 246 // transactions or transactions not yet broadcast by the wallet) are given a bump fee of 0. 247 // 248 // If multiple outpoints come from the same transaction (which would be very rare because 249 // it means that one transaction has multiple change outputs or paid the same wallet using multiple 250 // outputs in the same transaction) or have shared ancestry, the bump fees are calculated 251 // independently, i.e. as if only one of them is spent. This may result in double-fee-bumping. This 252 // caveat can be rectified per use of the sister-function CalculateCombinedBumpFee(…). 253 virtual std::map<COutPoint, CAmount> calculateIndividualBumpFees(const std::vector<COutPoint>& outpoints, const CFeeRate& target_feerate) = 0; 254 255 //! Calculate the combined bump fee for an input set per the same strategy 256 // as in CalculateIndividualBumpFees(…). 257 // Unlike CalculateIndividualBumpFees(…), this does not return individual 258 // bump fees per outpoint, but a single bump fee for the shared ancestry. 259 // The combined bump fee may be used to correct overestimation due to 260 // shared ancestry by multiple UTXOs after coin selection. 261 virtual std::optional<CAmount> calculateCombinedBumpFee(const std::vector<COutPoint>& outpoints, const CFeeRate& target_feerate) = 0; 262 263 //! Get the node's package limits. 264 //! Currently only returns the ancestor and descendant count limits, but could be enhanced to 265 //! return more policy settings. 266 virtual void getPackageLimits(unsigned int& limit_ancestor_count, unsigned int& limit_descendant_count) = 0; 267 268 //! Check if transaction will pass the mempool's chain limits. 269 virtual util::Result<void> checkChainLimits(const CTransactionRef& tx) = 0; 270 271 //! Estimate smart fee. 272 virtual CFeeRate estimateSmartFee(int num_blocks, bool conservative, FeeCalculation* calc = nullptr) = 0; 273 274 //! Fee estimator max target. 275 virtual unsigned int estimateMaxBlocks() = 0; 276 277 //! Mempool minimum fee. 278 virtual CFeeRate mempoolMinFee() = 0; 279 280 //! Relay current minimum fee (from -minrelaytxfee and -incrementalrelayfee settings). 281 virtual CFeeRate relayMinFee() = 0; 282 283 //! Relay incremental fee setting (-incrementalrelayfee), reflecting cost of relay. 284 virtual CFeeRate relayIncrementalFee() = 0; 285 286 //! Relay dust fee setting (-dustrelayfee), reflecting lowest rate it's economical to spend. 287 virtual CFeeRate relayDustFee() = 0; 288 289 //! Check if any block has been pruned. 290 virtual bool havePruned() = 0; 291 292 //! Get the current prune height. 293 virtual std::optional<int> getPruneHeight() = 0; 294 295 //! Check if the node is ready to broadcast transactions. 296 virtual bool isReadyToBroadcast() = 0; 297 298 //! Check if in IBD. 299 virtual bool isInitialBlockDownload() = 0; 300 301 //! Check if shutdown requested. 302 virtual bool shutdownRequested() = 0; 303 304 //! Send init message. 305 virtual void initMessage(const std::string& message) = 0; 306 307 //! Send init warning. 308 virtual void initWarning(const bilingual_str& message) = 0; 309 310 //! Send init error. 311 virtual void initError(const bilingual_str& message) = 0; 312 313 //! Send progress indicator. 314 virtual void showProgress(const std::string& title, int progress, bool resume_possible) = 0; 315 316 //! Chain notifications. 317 class Notifications 318 { 319 public: 320 virtual ~Notifications() = default; 321 virtual void transactionAddedToMempool(const CTransactionRef& tx) {} 322 virtual void transactionRemovedFromMempool(const CTransactionRef& tx, MemPoolRemovalReason reason) {} 323 virtual void blockConnected(ChainstateRole role, const BlockInfo& block) {} 324 virtual void blockDisconnected(const BlockInfo& block) {} 325 virtual void updatedBlockTip() {} 326 virtual void chainStateFlushed(ChainstateRole role, const CBlockLocator& locator) {} 327 }; 328 329 //! Register handler for notifications. 330 virtual std::unique_ptr<Handler> handleNotifications(std::shared_ptr<Notifications> notifications) = 0; 331 332 //! Wait for pending notifications to be processed unless block hash points to the current 333 //! chain tip. 334 virtual void waitForNotificationsIfTipChanged(const uint256& old_tip) = 0; 335 336 //! Register handler for RPC. Command is not copied, so reference 337 //! needs to remain valid until Handler is disconnected. 338 virtual std::unique_ptr<Handler> handleRpc(const CRPCCommand& command) = 0; 339 340 //! Check if deprecated RPC is enabled. 341 virtual bool rpcEnableDeprecated(const std::string& method) = 0; 342 343 //! Run function after given number of seconds. Cancel any previous calls with same name. 344 virtual void rpcRunLater(const std::string& name, std::function<void()> fn, int64_t seconds) = 0; 345 346 //! Get settings value. 347 virtual common::SettingsValue getSetting(const std::string& arg) = 0; 348 349 //! Get list of settings values. 350 virtual std::vector<common::SettingsValue> getSettingsList(const std::string& arg) = 0; 351 352 //! Return <datadir>/settings.json setting value. 353 virtual common::SettingsValue getRwSetting(const std::string& name) = 0; 354 355 //! Updates a setting in <datadir>/settings.json. 356 //! Null can be passed to erase the setting. There is intentionally no 357 //! support for writing null values to settings.json. 358 //! Depending on the action returned by the update function, this will either 359 //! update the setting in memory or write the updated settings to disk. 360 virtual bool updateRwSetting(const std::string& name, const SettingsUpdate& update_function) = 0; 361 362 //! Replace a setting in <datadir>/settings.json with a new value. 363 //! Null can be passed to erase the setting. 364 //! This method provides a simpler alternative to updateRwSetting when 365 //! atomically reading and updating the setting is not required. 366 virtual bool overwriteRwSetting(const std::string& name, common::SettingsValue value, SettingsAction action = SettingsAction::WRITE) = 0; 367 368 //! Delete a given setting in <datadir>/settings.json. 369 //! This method provides a simpler alternative to overwriteRwSetting when 370 //! erasing a setting, for ease of use and readability. 371 virtual bool deleteRwSettings(const std::string& name, SettingsAction action = SettingsAction::WRITE) = 0; 372 373 //! Synchronously send transactionAddedToMempool notifications about all 374 //! current mempool transactions to the specified handler and return after 375 //! the last one is sent. These notifications aren't coordinated with async 376 //! notifications sent by handleNotifications, so out of date async 377 //! notifications from handleNotifications can arrive during and after 378 //! synchronous notifications from requestMempoolTransactions. Clients need 379 //! to be prepared to handle this by ignoring notifications about unknown 380 //! removed transactions and already added new transactions. 381 virtual void requestMempoolTransactions(Notifications& notifications) = 0; 382 383 //! Return true if an assumed-valid chain is in use. 384 virtual bool hasAssumedValidChain() = 0; 385 386 //! Get internal node context. Useful for testing, but not 387 //! accessible across processes. 388 virtual node::NodeContext* context() { return nullptr; } 389 }; 390 391 //! Interface to let node manage chain clients (wallets, or maybe tools for 392 //! monitoring and analysis in the future). 393 class ChainClient 394 { 395 public: 396 virtual ~ChainClient() = default; 397 398 //! Register rpcs. 399 virtual void registerRpcs() = 0; 400 401 //! Check for errors before loading. 402 virtual bool verify() = 0; 403 404 //! Load saved state. 405 virtual bool load() = 0; 406 407 //! Start client execution and provide a scheduler. 408 virtual void start(CScheduler& scheduler) = 0; 409 410 //! Save state to disk. 411 virtual void flush() = 0; 412 413 //! Shut down client. 414 virtual void stop() = 0; 415 416 //! Set mock time. 417 virtual void setMockTime(int64_t time) = 0; 418 419 //! Mock the scheduler to fast forward in time. 420 virtual void schedulerMockForward(std::chrono::seconds delta_seconds) = 0; 421 }; 422 423 //! Return implementation of Chain interface. 424 std::unique_ptr<Chain> MakeChain(node::NodeContext& node); 425 426 } // namespace interfaces 427 428 #endif // BITCOIN_INTERFACES_CHAIN_H