Line data    Source code

       1             : // Copyright (c) 2009-2010 Satoshi Nakamoto
       2             : // Copyright (c) 2009-2022 The Bitcoin Core developers
       3             : // Distributed under the MIT software license, see the accompanying
       4             : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       5             : 
       6             : #include <node/miner.h>
       7             : 
       8             : #include <chain.h>
       9             : #include <chainparams.h>
      10             : #include <coins.h>
      11             : #include <common/args.h>
      12             : #include <consensus/amount.h>
      13             : #include <consensus/consensus.h>
      14             : #include <consensus/merkle.h>
      15             : #include <consensus/tx_verify.h>
      16             : #include <consensus/validation.h>
      17           2 : #include <deploymentstatus.h>
      18           2 : #include <logging.h>
      19             : #include <policy/feerate.h>
      20             : #include <policy/policy.h>
      21             : #include <pow.h>
      22             : #include <primitives/transaction.h>
      23             : #include <timedata.h>
      24             : #include <util/moneystr.h>
      25             : #include <validation.h>
      26             : 
      27             : #include <algorithm>
      28             : #include <utility>
      29             : 
      30             : namespace node {
      31        5059 : int64_t UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev)
      32             : {
      33        5059 :     int64_t nOldTime = pblock->nTime;
      34        5059 :     int64_t nNewTime{std::max<int64_t>(pindexPrev->GetMedianTimePast() + 1, TicksSinceEpoch<std::chrono::seconds>(GetAdjustedTime()))};
      35             : 
      36        5059 :     if (nOldTime < nNewTime) {
      37           0 :         pblock->nTime = nNewTime;
      38           0 :     }
      39             : 
      40             :     // Updating time can change work required on testnet:
      41        5059 :     if (consensusParams.fPowAllowMinDifficultyBlocks) {
      42        5059 :         pblock->nBits = GetNextWorkRequired(pindexPrev, pblock, consensusParams);
      43        5059 :     }
      44             : 
      45        5059 :     return nNewTime - nOldTime;
      46             : }
      47             : 
      48           0 : void RegenerateCommitments(CBlock& block, ChainstateManager& chainman)
      49             : {
      50           0 :     CMutableTransaction tx{*block.vtx.at(0)};
      51           0 :     tx.vout.erase(tx.vout.begin() + GetWitnessCommitmentIndex(block));
      52           0 :     block.vtx.at(0) = MakeTransactionRef(tx);
      53             : 
      54           0 :     const CBlockIndex* prev_block = WITH_LOCK(::cs_main, return chainman.m_blockman.LookupBlockIndex(block.hashPrevBlock));
      55           0 :     chainman.GenerateCoinbaseCommitment(block, prev_block);
      56             : 
      57           0 :     block.hashMerkleRoot = BlockMerkleRoot(block);
      58           0 : }
      59             : 
      60        5059 : static BlockAssembler::Options ClampOptions(BlockAssembler::Options options)
      61             : {
      62             :     // Limit weight to between 4K and DEFAULT_BLOCK_MAX_WEIGHT for sanity:
      63        5059 :     options.nBlockMaxWeight = std::clamp<size_t>(options.nBlockMaxWeight, 4000, DEFAULT_BLOCK_MAX_WEIGHT);
      64        5059 :     return options;
      65             : }
      66             : 
      67        5059 : BlockAssembler::BlockAssembler(Chainstate& chainstate, const CTxMemPool* mempool, const Options& options)
      68        5059 :     : chainparams{chainstate.m_chainman.GetParams()},
      69        5059 :       m_mempool{mempool},
      70        5059 :       m_chainstate{chainstate},
      71        5059 :       m_options{ClampOptions(options)}
      72             : {
      73        5059 : }
      74           2 : 
      75         200 : void ApplyArgsManOptions(const ArgsManager& args, BlockAssembler::Options& options)
      76             : {
      77             :     // Block resource limits
      78         200 :     options.nBlockMaxWeight = args.GetIntArg("-blockmaxweight", options.nBlockMaxWeight);
      79         200 :     if (const auto blockmintxfee{args.GetArg("-blockmintxfee")}) {
      80           0 :         if (const auto parsed{ParseMoney(*blockmintxfee)}) options.blockMinFeeRate = CFeeRate{*parsed};
      81           0 :     }
      82         200 : }
      83           0 : static BlockAssembler::Options ConfiguredOptions()
      84             : {
      85           0 :     BlockAssembler::Options options;
      86           0 :     ApplyArgsManOptions(gArgs, options);
      87           0 :     return options;
      88             : }
      89             : 
      90           0 : BlockAssembler::BlockAssembler(Chainstate& chainstate, const CTxMemPool* mempool)
      91           0 :     : BlockAssembler(chainstate, mempool, ConfiguredOptions()) {}
      92             : 
      93        5059 : void BlockAssembler::resetBlock()
      94             : {
      95        5059 :     inBlock.clear();
      96             : 
      97             :     // Reserve space for coinbase tx
      98        5059 :     nBlockWeight = 4000;
      99        5059 :     nBlockSigOpsCost = 400;
     100             : 
     101             :     // These counters do not include coinbase tx
     102        5059 :     nBlockTx = 0;
     103        5059 :     nFees = 0;
     104        5059 : }
     105             : 
     106        5059 : std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& scriptPubKeyIn)
     107             : {
     108        5059 :     const auto time_start{SteadyClock::now()};
     109             : 
     110        5059 :     resetBlock();
     111             : 
     112        5059 :     pblocktemplate.reset(new CBlockTemplate());
     113             : 
     114        5059 :     if (!pblocktemplate.get()) {
     115           0 :         return nullptr;
     116             :     }
     117        5059 :     CBlock* const pblock = &pblocktemplate->block; // pointer for convenience
     118             : 
     119             :     // Add dummy coinbase tx as first transaction
     120        5059 :     pblock->vtx.emplace_back();
     121        5059 :     pblocktemplate->vTxFees.push_back(-1); // updated at end
     122        5059 :     pblocktemplate->vTxSigOpsCost.push_back(-1); // updated at end
     123             : 
     124        5059 :     LOCK(::cs_main);
     125        5059 :     CBlockIndex* pindexPrev = m_chainstate.m_chain.Tip();
     126        5059 :     assert(pindexPrev != nullptr);
     127        5059 :     nHeight = pindexPrev->nHeight + 1;
     128             : 
     129        5059 :     pblock->nVersion = m_chainstate.m_chainman.m_versionbitscache.ComputeBlockVersion(pindexPrev, chainparams.GetConsensus());
     130             :     // -regtest only: allow overriding block.nVersion with
     131             :     // -blockversion=N to test forking scenarios
     132        5059 :     if (chainparams.MineBlocksOnDemand()) {
     133        5059 :         pblock->nVersion = gArgs.GetIntArg("-blockversion", pblock->nVersion);
     134        5059 :     }
     135             : 
     136        5059 :     pblock->nTime = TicksSinceEpoch<std::chrono::seconds>(GetAdjustedTime());
     137        5059 :     m_lock_time_cutoff = pindexPrev->GetMedianTimePast();
     138             : 
     139        5059 :     int nPackagesSelected = 0;
     140        5059 :     int nDescendantsUpdated = 0;
     141        5059 :     if (m_mempool) {
     142        5059 :         LOCK(m_mempool->cs);
     143        5059 :         addPackageTxs(*m_mempool, nPackagesSelected, nDescendantsUpdated);
     144        5059 :     }
     145             : 
     146        5059 :     const auto time_1{SteadyClock::now()};
     147             : 
     148        5059 :     m_last_block_num_txs = nBlockTx;
     149        5059 :     m_last_block_weight = nBlockWeight;
     150             : 
     151             :     // Create coinbase transaction.
     152        5059 :     CMutableTransaction coinbaseTx;
     153        5059 :     coinbaseTx.vin.resize(1);
     154        5059 :     coinbaseTx.vin[0].prevout.SetNull();
     155        5059 :     coinbaseTx.vout.resize(1);
     156        5059 :     coinbaseTx.vout[0].scriptPubKey = scriptPubKeyIn;
     157        5059 :     coinbaseTx.vout[0].nValue = nFees + GetBlockSubsidy(nHeight, chainparams.GetConsensus());
     158        5059 :     coinbaseTx.vin[0].scriptSig = CScript() << nHeight << OP_0;
     159        5059 :     pblock->vtx[0] = MakeTransactionRef(std::move(coinbaseTx));
     160        5059 :     pblocktemplate->vchCoinbaseCommitment = m_chainstate.m_chainman.GenerateCoinbaseCommitment(*pblock, pindexPrev);
     161        5059 :     pblocktemplate->vTxFees[0] = -nFees;
     162             : 
     163        5059 :     LogPrintf("CreateNewBlock(): block weight: %u txs: %u fees: %ld sigops %d\n", GetBlockWeight(*pblock), nBlockTx, nFees, nBlockSigOpsCost);
     164             : 
     165             :     // Fill in header
     166        5059 :     pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
     167        5059 :     UpdateTime(pblock, chainparams.GetConsensus(), pindexPrev);
     168        5059 :     pblock->nBits          = GetNextWorkRequired(pindexPrev, pblock, chainparams.GetConsensus());
     169        5059 :     pblock->nNonce         = 0;
     170        5059 :     pblocktemplate->vTxSigOpsCost[0] = WITNESS_SCALE_FACTOR * GetLegacySigOpCount(*pblock->vtx[0]);
     171             : 
     172        5059 :     BlockValidationState state;
     173        5059 :     if (m_options.test_block_validity && !TestBlockValidity(state, chainparams, m_chainstate, *pblock, pindexPrev,
     174        5059 :                                                   GetAdjustedTime, /*fCheckPOW=*/false, /*fCheckMerkleRoot=*/false)) {
     175           0 :         throw std::runtime_error(strprintf("%s: TestBlockValidity failed: %s", __func__, state.ToString()));
     176             :     }
     177        5059 :     const auto time_2{SteadyClock::now()};
     178             : 
     179        5059 :     LogPrint(BCLog::BENCH, "CreateNewBlock() packages: %.2fms (%d packages, %d updated descendants), validity: %.2fms (total %.2fms)\n",
     180             :              Ticks<MillisecondsDouble>(time_1 - time_start), nPackagesSelected, nDescendantsUpdated,
     181             :              Ticks<MillisecondsDouble>(time_2 - time_1),
     182             :              Ticks<MillisecondsDouble>(time_2 - time_start));
     183             : 
     184        5059 :     return std::move(pblocktemplate);
     185        5059 : }
     186             : 
     187         804 : void BlockAssembler::onlyUnconfirmed(CTxMemPool::setEntries& testSet)
     188             : {
     189         846 :     for (CTxMemPool::setEntries::iterator iit = testSet.begin(); iit != testSet.end(); ) {
     190             :         // Only test txs not already in the block
     191          42 :         if (inBlock.count(*iit)) {
     192          31 :             testSet.erase(iit++);
     193          31 :         } else {
     194          11 :             iit++;
     195             :         }
     196             :     }
     197         804 : }
     198             : 
     199        1858 : bool BlockAssembler::TestPackage(uint64_t packageSize, int64_t packageSigOpsCost) const
     200             : {
     201             :     // TODO: switch to weight-based accounting for packages instead of vsize-based accounting.
     202        1858 :     if (nBlockWeight + WITNESS_SCALE_FACTOR * packageSize >= m_options.nBlockMaxWeight) {
     203        1054 :         return false;
     204             :     }
     205         804 :     if (nBlockSigOpsCost + packageSigOpsCost >= MAX_BLOCK_SIGOPS_COST) {
     206           0 :         return false;
     207             :     }
     208         804 :     return true;
     209        1858 : }
     210             : 
     211             : // Perform transaction-level checks before adding to block:
     212             : // - transaction finality (locktime)
     213         804 : bool BlockAssembler::TestPackageTransactions(const CTxMemPool::setEntries& package) const
     214             : {
     215        1619 :     for (CTxMemPool::txiter it : package) {
     216         815 :         if (!IsFinalTx(it->GetTx(), nHeight, m_lock_time_cutoff)) {
     217           0 :             return false;
     218             :         }
     219             :     }
     220         804 :     return true;
     221         804 : }
     222             : 
     223         815 : void BlockAssembler::AddToBlock(CTxMemPool::txiter iter)
     224             : {
     225         815 :     pblocktemplate->block.vtx.emplace_back(iter->GetSharedTx());
     226         815 :     pblocktemplate->vTxFees.push_back(iter->GetFee());
     227         815 :     pblocktemplate->vTxSigOpsCost.push_back(iter->GetSigOpCost());
     228         815 :     nBlockWeight += iter->GetTxWeight();
     229         815 :     ++nBlockTx;
     230         815 :     nBlockSigOpsCost += iter->GetSigOpCost();
     231         815 :     nFees += iter->GetFee();
     232         815 :     inBlock.insert(iter);
     233             : 
     234         815 :     bool fPrintPriority = gArgs.GetBoolArg("-printpriority", DEFAULT_PRINTPRIORITY);
     235         815 :     if (fPrintPriority) {
     236           0 :         LogPrintf("fee rate %s txid %s\n",
     237             :                   CFeeRate(iter->GetModifiedFee(), iter->GetTxSize()).ToString(),
     238             :                   iter->GetTx().GetHash().ToString());
     239           0 :     }
     240         815 : }
     241             : 
     242             : /** Add descendants of given transactions to mapModifiedTx with ancestor
     243             :  * state updated assuming given transactions are inBlock. Returns number
     244             :  * of updated descendants. */
     245         804 : static int UpdatePackagesForAdded(const CTxMemPool& mempool,
     246             :                                   const CTxMemPool::setEntries& alreadyAdded,
     247             :                                   indexed_modified_transaction_set& mapModifiedTx) EXCLUSIVE_LOCKS_REQUIRED(mempool.cs)
     248             : {
     249         804 :     AssertLockHeld(mempool.cs);
     250             : 
     251         804 :     int nDescendantsUpdated = 0;
     252        1619 :     for (CTxMemPool::txiter it : alreadyAdded) {
     253         815 :         CTxMemPool::setEntries descendants;
     254         815 :         mempool.CalculateDescendants(it, descendants);
     255             :         // Insert all descendants (not yet in block) into the modified set
     256        1678 :         for (CTxMemPool::txiter desc : descendants) {
     257         863 :             if (alreadyAdded.count(desc)) {
     258         826 :                 continue;
     259             :             }
     260          37 :             ++nDescendantsUpdated;
     261          37 :             modtxiter mit = mapModifiedTx.find(desc);
     262          37 :             if (mit == mapModifiedTx.end()) {
     263          37 :                 CTxMemPoolModifiedEntry modEntry(desc);
     264          37 :                 mit = mapModifiedTx.insert(modEntry).first;
     265          37 :             }
     266          37 :             mapModifiedTx.modify(mit, update_for_parent_inclusion(it));
     267             :         }
     268         815 :     }
     269         804 :     return nDescendantsUpdated;
     270           0 : }
     271             : 
     272         804 : void BlockAssembler::SortForBlock(const CTxMemPool::setEntries& package, std::vector<CTxMemPool::txiter>& sortedEntries)
     273             : {
     274             :     // Sort package by ancestor count
     275             :     // If a transaction A depends on transaction B, then A's ancestor count
     276             :     // must be greater than B's.  So this is sufficient to validly order the
     277             :     // transactions for block inclusion.
     278         804 :     sortedEntries.clear();
     279         804 :     sortedEntries.insert(sortedEntries.begin(), package.begin(), package.end());
     280         804 :     std::sort(sortedEntries.begin(), sortedEntries.end(), CompareTxIterByAncestorCount());
     281         804 : }
     282             : 
     283             : // This transaction selection algorithm orders the mempool based
     284             : // on feerate of a transaction including all unconfirmed ancestors.
     285             : // Since we don't remove transactions from the mempool as we select them
     286             : // for block inclusion, we need an alternate method of updating the feerate
     287             : // of a transaction with its not-yet-selected ancestors as we go.
     288             : // This is accomplished by walking the in-mempool descendants of selected
     289             : // transactions and storing a temporary modified state in mapModifiedTxs.
     290             : // Each time through the loop, we compare the best transaction in
     291             : // mapModifiedTxs with the next transaction in the mempool to decide what
     292             : // transaction package to work on next.
     293        5059 : void BlockAssembler::addPackageTxs(const CTxMemPool& mempool, int& nPackagesSelected, int& nDescendantsUpdated)
     294             : {
     295        5059 :     AssertLockHeld(mempool.cs);
     296             : 
     297             :     // mapModifiedTx will store sorted packages after they are modified
     298             :     // because some of their txs are already in the block
     299        5059 :     indexed_modified_transaction_set mapModifiedTx;
     300             :     // Keep track of entries that failed inclusion, to avoid duplicate work
     301        5059 :     CTxMemPool::setEntries failedTx;
     302             : 
     303        5059 :     CTxMemPool::indexed_transaction_set::index<ancestor_score>::type::iterator mi = mempool.mapTx.get<ancestor_score>().begin();
     304        5059 :     CTxMemPool::txiter iter;
     305             : 
     306             :     // Limit the number of attempts to add transactions to the block when it is
     307             :     // close to full; this is just a simple heuristic to finish quickly if the
     308             :     // mempool has a lot of entries.
     309        5059 :     const int64_t MAX_CONSECUTIVE_FAILURES = 1000;
     310        5059 :     int64_t nConsecutiveFailed = 0;
     311             : 
     312        6965 :     while (mi != mempool.mapTx.get<ancestor_score>().end() || !mapModifiedTx.empty()) {
     313             :         // First try to find a new transaction in mapTx to evaluate.
     314             :         //
     315             :         // Skip entries in mapTx that are already in a block or are present
     316             :         // in mapModifiedTx (which implies that the mapTx ancestor state is
     317             :         // stale due to ancestor inclusion in the block)
     318             :         // Also skip transactions that we've already failed to add. This can happen if
     319             :         // we consider a transaction in mapModifiedTx and it fails: we can then
     320             :         // potentially consider it again while walking mapTx.  It's currently
     321             :         // guaranteed to fail again, but as a belt-and-suspenders check we put it in
     322             :         // failedTx and avoid re-evaluation, since the re-evaluation would be using
     323             :         // cached size/sigops/fee values that are not actually correct.
     324             :         /** Return true if given transaction from mapTx has already been evaluated,
     325             :          * or if the transaction's cached data in mapTx is incorrect. */
     326        1939 :         if (mi != mempool.mapTx.get<ancestor_score>().end()) {
     327        1902 :             auto it = mempool.mapTx.project<0>(mi);
     328        1902 :             assert(it != mempool.mapTx.end());
     329        1902 :             if (mapModifiedTx.count(it) || inBlock.count(it) || failedTx.count(it)) {
     330          48 :                 ++mi;
     331          48 :                 continue;
     332             :             }
     333        1854 :         }
     334             : 
     335             :         // Now that mi is not stale, determine which transaction to evaluate:
     336             :         // the next entry from mapTx, or the best from mapModifiedTx?
     337        1891 :         bool fUsingModified = false;
     338             : 
     339        1891 :         modtxscoreiter modit = mapModifiedTx.get<ancestor_score>().begin();
     340        1891 :         if (mi == mempool.mapTx.get<ancestor_score>().end()) {
     341             :             // We're out of entries in mapTx; use the entry from mapModifiedTx
     342          37 :             iter = modit->iter;
     343          37 :             fUsingModified = true;
     344          37 :         } else {
     345             :             // Try to compare the mapTx entry to the mapModifiedTx entry
     346        1854 :             iter = mempool.mapTx.project<0>(mi);
     347        1855 :             if (modit != mapModifiedTx.get<ancestor_score>().end() &&
     348           1 :                     CompareTxMemPoolEntryByAncestorFee()(*modit, CTxMemPoolModifiedEntry(iter))) {
     349             :                 // The best entry in mapModifiedTx has higher score
     350             :                 // than the one from mapTx.
     351             :                 // Switch which transaction (package) to consider
     352           0 :                 iter = modit->iter;
     353           0 :                 fUsingModified = true;
     354           0 :             } else {
     355             :                 // Either no entry in mapModifiedTx, or it's worse than mapTx.
     356             :                 // Increment mi for the next loop iteration.
     357        1854 :                 ++mi;
     358             :             }
     359             :         }
     360             : 
     361             :         // We skip mapTx entries that are inBlock, and mapModifiedTx shouldn't
     362             :         // contain anything that is inBlock.
     363        1891 :         assert(!inBlock.count(iter));
     364             : 
     365        1891 :         uint64_t packageSize = iter->GetSizeWithAncestors();
     366        1891 :         CAmount packageFees = iter->GetModFeesWithAncestors();
     367        1891 :         int64_t packageSigOpsCost = iter->GetSigOpCostWithAncestors();
     368        1891 :         if (fUsingModified) {
     369          37 :             packageSize = modit->nSizeWithAncestors;
     370          37 :             packageFees = modit->nModFeesWithAncestors;
     371          37 :             packageSigOpsCost = modit->nSigOpCostWithAncestors;
     372          37 :         }
     373             : 
     374        1891 :         if (packageFees < m_options.blockMinFeeRate.GetFee(packageSize)) {
     375             :             // Everything else we might consider has a lower fee rate
     376          33 :             return;
     377             :         }
     378             : 
     379        1858 :         if (!TestPackage(packageSize, packageSigOpsCost)) {
     380        1054 :             if (fUsingModified) {
     381             :                 // Since we always look at the best entry in mapModifiedTx,
     382             :                 // we must erase failed entries so that we can consider the
     383             :                 // next best entry on the next loop iteration
     384           0 :                 mapModifiedTx.get<ancestor_score>().erase(modit);
     385           0 :                 failedTx.insert(iter);
     386           0 :             }
     387             : 
     388        1054 :             ++nConsecutiveFailed;
     389             : 
     390        1054 :             if (nConsecutiveFailed > MAX_CONSECUTIVE_FAILURES && nBlockWeight >
     391           0 :                     m_options.nBlockMaxWeight - 4000) {
     392             :                 // Give up if we're close to full and haven't succeeded in a while
     393           0 :                 break;
     394             :             }
     395        1054 :             continue;
     396             :         }
     397             : 
     398         804 :         auto ancestors{mempool.AssumeCalculateMemPoolAncestors(__func__, *iter, CTxMemPool::Limits::NoLimits(), /*fSearchForParents=*/false)};
     399             : 
     400         804 :         onlyUnconfirmed(ancestors);
     401         804 :         ancestors.insert(iter);
     402             : 
     403             :         // Test if all tx's are Final
     404         804 :         if (!TestPackageTransactions(ancestors)) {
     405           0 :             if (fUsingModified) {
     406           0 :                 mapModifiedTx.get<ancestor_score>().erase(modit);
     407           0 :                 failedTx.insert(iter);
     408           0 :             }
     409           0 :             continue;
     410             :         }
     411             : 
     412             :         // This transaction will make it in; reset the failed counter.
     413         804 :         nConsecutiveFailed = 0;
     414             : 
     415             :         // Package can be added. Sort the entries in a valid order.
     416         804 :         std::vector<CTxMemPool::txiter> sortedEntries;
     417         804 :         SortForBlock(ancestors, sortedEntries);
     418             : 
     419        1619 :         for (size_t i = 0; i < sortedEntries.size(); ++i) {
     420         815 :             AddToBlock(sortedEntries[i]);
     421             :             // Erase from the modified set, if present
     422         815 :             mapModifiedTx.erase(sortedEntries[i]);
     423         815 :         }
     424             : 
     425         804 :         ++nPackagesSelected;
     426             : 
     427             :         // Update transactions that depend on each of these
     428         804 :         nDescendantsUpdated += UpdatePackagesForAdded(mempool, ancestors, mapModifiedTx);
     429         804 :     }
     430        5059 : }
     431             : } // namespace node