1  // Copyright (c) 2010 Satoshi Nakamoto
  2  // Copyright (c) 2009-2021 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 <consensus/validation.h>
  7  #include <index/txindex.h>
  8  #include <net.h>
  9  #include <net_processing.h>
 10  #include <node/blockstorage.h>
 11  #include <node/context.h>
 12  #include <node/types.h>
 13  #include <txmempool.h>
 14  #include <validation.h>
 15  #include <validationinterface.h>
 16  #include <node/transaction.h>
 17  
 18  #include <future>
 19  
 20  namespace node {
 21  static TransactionError HandleATMPError(const TxValidationState& state, std::string& err_string_out)
 22  {
 23      err_string_out = state.ToString();
 24      if (state.IsInvalid()) {
 25          if (state.GetResult() == TxValidationResult::TX_MISSING_INPUTS) {
 26              return TransactionError::MISSING_INPUTS;
 27          }
 28          return TransactionError::MEMPOOL_REJECTED;
 29      } else {
 30          return TransactionError::MEMPOOL_ERROR;
 31      }
 32  }
 33  
 34  TransactionError BroadcastTransaction(NodeContext& node,
 35                                        const CTransactionRef tx,
 36                                        std::string& err_string,
 37                                        const CAmount& max_tx_fee,
 38                                        TxBroadcast broadcast_method,
 39                                        bool wait_callback)
 40  {
 41      // BroadcastTransaction can be called by RPC or by the wallet.
 42      // chainman, mempool and peerman are initialized before the RPC server and wallet are started
 43      // and reset after the RPC sever and wallet are stopped.
 44      assert(node.chainman);
 45      assert(node.mempool);
 46      assert(node.peerman);
 47  
 48      std::promise<void> promise;
 49      Txid txid = tx->GetHash();
 50      Wtxid wtxid = tx->GetWitnessHash();
 51      bool callback_set = false;
 52  
 53      {
 54          LOCK(cs_main);
 55  
 56          // If the transaction is already confirmed in the chain, don't do anything
 57          // and return early.
 58          CCoinsViewCache &view = node.chainman->ActiveChainstate().CoinsTip();
 59          for (size_t o = 0; o < tx->vout.size(); o++) {
 60              const Coin& existingCoin = view.AccessCoin(COutPoint(txid, o));
 61              // IsSpent doesn't mean the coin is spent, it means the output doesn't exist.
 62              // So if the output does exist, then this transaction exists in the chain.
 63              if (!existingCoin.IsSpent()) return TransactionError::ALREADY_IN_UTXO_SET;
 64          }
 65  
 66          if (auto mempool_tx = node.mempool->get(txid); mempool_tx) {
 67              // There's already a transaction in the mempool with this txid. Don't
 68              // try to submit this transaction to the mempool (since it'll be
 69              // rejected as a TX_CONFLICT), but do attempt to reannounce the mempool
 70              // transaction if broadcast_method is not TxBroadcast::MEMPOOL_NO_BROADCAST.
 71              //
 72              // The mempool transaction may have the same or different witness (and
 73              // wtxid) as this transaction. Use the mempool's wtxid for reannouncement.
 74              wtxid = mempool_tx->GetWitnessHash();
 75          } else {
 76              // Transaction is not already in the mempool.
 77              if (max_tx_fee > 0) {
 78                  // First, call ATMP with test_accept and check the fee. If ATMP
 79                  // fails here, return error immediately.
 80                  const MempoolAcceptResult result = node.chainman->ProcessTransaction(tx, /*test_accept=*/ true);
 81                  if (result.m_result_type != MempoolAcceptResult::ResultType::VALID) {
 82                      return HandleATMPError(result.m_state, err_string);
 83                  } else if (result.m_base_fees.value() > max_tx_fee) {
 84                      return TransactionError::MAX_FEE_EXCEEDED;
 85                  }
 86              }
 87  
 88              switch (broadcast_method) {
 89              case TxBroadcast::MEMPOOL_NO_BROADCAST:
 90              case TxBroadcast::MEMPOOL_AND_BROADCAST_TO_ALL:
 91                  // Try to submit the transaction to the mempool.
 92                  {
 93                      const MempoolAcceptResult result =
 94                          node.chainman->ProcessTransaction(tx, /*test_accept=*/false);
 95                      if (result.m_result_type != MempoolAcceptResult::ResultType::VALID) {
 96                          return HandleATMPError(result.m_state, err_string);
 97                      }
 98                  }
 99                  // Transaction was accepted to the mempool.
100  
101                  if (broadcast_method == TxBroadcast::MEMPOOL_AND_BROADCAST_TO_ALL) {
102                      // the mempool tracks locally submitted transactions to make a
103                      // best-effort of initial broadcast
104                      node.mempool->AddUnbroadcastTx(txid);
105                  }
106                  break;
107              }
108  
109              if (wait_callback && node.validation_signals) {
110                  // For transactions broadcast from outside the wallet, make sure
111                  // that the wallet has been notified of the transaction before
112                  // continuing.
113                  //
114                  // This prevents a race where a user might call sendrawtransaction
115                  // with a transaction to/from their wallet, immediately call some
116                  // wallet RPC, and get a stale result because callbacks have not
117                  // yet been processed.
118                  node.validation_signals->CallFunctionInValidationInterfaceQueue([&promise] {
119                      promise.set_value();
120                  });
121                  callback_set = true;
122              }
123          }
124      } // cs_main
125  
126      if (callback_set) {
127          // Wait until Validation Interface clients have been notified of the
128          // transaction entering the mempool.
129          promise.get_future().wait();
130      }
131  
132      switch (broadcast_method) {
133      case TxBroadcast::MEMPOOL_NO_BROADCAST:
134          break;
135      case TxBroadcast::MEMPOOL_AND_BROADCAST_TO_ALL:
136          node.peerman->RelayTransaction(txid, wtxid);
137          break;
138      }
139  
140      return TransactionError::OK;
141  }
142  
143  CTransactionRef GetTransaction(const CBlockIndex* const block_index, const CTxMemPool* const mempool, const Txid& hash, const BlockManager& blockman, uint256& hashBlock)
144  {
145      if (mempool && !block_index) {
146          CTransactionRef ptx = mempool->get(hash);
147          if (ptx) return ptx;
148      }
149      if (g_txindex) {
150          CTransactionRef tx;
151          uint256 block_hash;
152          if (g_txindex->FindTx(hash, block_hash, tx)) {
153              if (!block_index || block_index->GetBlockHash() == block_hash) {
154                  // Don't return the transaction if the provided block hash doesn't match.
155                  // The case where a transaction appears in multiple blocks (e.g. reorgs or
156                  // BIP30) is handled by the block lookup below.
157                  hashBlock = block_hash;
158                  return tx;
159              }
160          }
161      }
162      if (block_index) {
163          CBlock block;
164          if (blockman.ReadBlock(block, *block_index)) {
165              for (const auto& tx : block.vtx) {
166                  if (tx->GetHash() == hash) {
167                      hashBlock = block_index->GetBlockHash();
168                      return tx;
169                  }
170              }
171          }
172      }
173      return nullptr;
174  }
175  } // namespace node