296 lines
13 KiB
C++
296 lines
13 KiB
C++
// Copyright (c) 2017 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#include "consensus/validation.h"
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#include "wallet/feebumper.h"
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#include "wallet/wallet.h"
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#include "policy/fees.h"
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#include "policy/policy.h"
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#include "policy/rbf.h"
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#include "validation.h" //for mempool access
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#include "txmempool.h"
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#include "utilmoneystr.h"
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#include "util.h"
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#include "net.h"
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// Calculate the size of the transaction assuming all signatures are max size
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// Use DummySignatureCreator, which inserts 72 byte signatures everywhere.
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// TODO: re-use this in CWallet::CreateTransaction (right now
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// CreateTransaction uses the constructed dummy-signed tx to do a priority
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// calculation, but we should be able to refactor after priority is removed).
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// NOTE: this requires that all inputs must be in mapWallet (eg the tx should
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// be IsAllFromMe).
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int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *pWallet)
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{
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CMutableTransaction txNew(tx);
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std::vector<CInputCoin> vCoins;
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// Look up the inputs. We should have already checked that this transaction
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// IsAllFromMe(ISMINE_SPENDABLE), so every input should already be in our
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// wallet, with a valid index into the vout array.
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for (auto& input : tx.vin) {
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const auto mi = pWallet->mapWallet.find(input.prevout.hash);
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assert(mi != pWallet->mapWallet.end() && input.prevout.n < mi->second.tx->vout.size());
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vCoins.emplace_back(CInputCoin(&(mi->second), input.prevout.n));
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}
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if (!pWallet->DummySignTx(txNew, vCoins)) {
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// This should never happen, because IsAllFromMe(ISMINE_SPENDABLE)
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// implies that we can sign for every input.
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return -1;
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}
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return GetVirtualTransactionSize(txNew);
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}
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bool CFeeBumper::preconditionChecks(const CWallet *pWallet, const CWalletTx& wtx) {
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if (pWallet->HasWalletSpend(wtx.GetHash())) {
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vErrors.push_back("Transaction has descendants in the wallet");
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currentResult = BumpFeeResult::INVALID_PARAMETER;
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return false;
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}
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{
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LOCK(mempool.cs);
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auto it_mp = mempool.mapTx.find(wtx.GetHash());
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if (it_mp != mempool.mapTx.end() && it_mp->GetCountWithDescendants() > 1) {
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vErrors.push_back("Transaction has descendants in the mempool");
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currentResult = BumpFeeResult::INVALID_PARAMETER;
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return false;
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}
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}
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if (wtx.GetDepthInMainChain() != 0) {
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vErrors.push_back("Transaction has been mined, or is conflicted with a mined transaction");
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currentResult = BumpFeeResult::WALLET_ERROR;
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return false;
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}
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return true;
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}
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CFeeBumper::CFeeBumper(const CWallet *pWallet, const uint256 txidIn, int newConfirmTarget, bool specifiedConfirmTarget, CAmount totalFee, bool newTxReplaceable)
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:
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txid(std::move(txidIn)),
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nOldFee(0),
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nNewFee(0)
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{
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vErrors.clear();
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bumpedTxid.SetNull();
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AssertLockHeld(pWallet->cs_wallet);
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if (!pWallet->mapWallet.count(txid)) {
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vErrors.push_back("Invalid or non-wallet transaction id");
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currentResult = BumpFeeResult::INVALID_ADDRESS_OR_KEY;
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return;
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}
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auto it = pWallet->mapWallet.find(txid);
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const CWalletTx& wtx = it->second;
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if (!preconditionChecks(pWallet, wtx)) {
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return;
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}
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if (!SignalsOptInRBF(wtx)) {
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vErrors.push_back("Transaction is not BIP 125 replaceable");
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currentResult = BumpFeeResult::WALLET_ERROR;
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return;
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}
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if (wtx.mapValue.count("replaced_by_txid")) {
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vErrors.push_back(strprintf("Cannot bump transaction %s which was already bumped by transaction %s", txid.ToString(), wtx.mapValue.at("replaced_by_txid")));
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currentResult = BumpFeeResult::WALLET_ERROR;
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return;
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}
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// check that original tx consists entirely of our inputs
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// if not, we can't bump the fee, because the wallet has no way of knowing the value of the other inputs (thus the fee)
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if (!pWallet->IsAllFromMe(wtx, ISMINE_SPENDABLE)) {
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vErrors.push_back("Transaction contains inputs that don't belong to this wallet");
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currentResult = BumpFeeResult::WALLET_ERROR;
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return;
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}
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// figure out which output was change
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// if there was no change output or multiple change outputs, fail
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int nOutput = -1;
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for (size_t i = 0; i < wtx.tx->vout.size(); ++i) {
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if (pWallet->IsChange(wtx.tx->vout[i])) {
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if (nOutput != -1) {
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vErrors.push_back("Transaction has multiple change outputs");
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currentResult = BumpFeeResult::WALLET_ERROR;
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return;
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}
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nOutput = i;
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}
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}
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if (nOutput == -1) {
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vErrors.push_back("Transaction does not have a change output");
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currentResult = BumpFeeResult::WALLET_ERROR;
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return;
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}
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// Calculate the expected size of the new transaction.
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int64_t txSize = GetVirtualTransactionSize(*(wtx.tx));
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const int64_t maxNewTxSize = CalculateMaximumSignedTxSize(*wtx.tx, pWallet);
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if (maxNewTxSize < 0) {
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vErrors.push_back("Transaction contains inputs that cannot be signed");
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currentResult = BumpFeeResult::INVALID_ADDRESS_OR_KEY;
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return;
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}
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// calculate the old fee and fee-rate
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nOldFee = wtx.GetDebit(ISMINE_SPENDABLE) - wtx.tx->GetValueOut();
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CFeeRate nOldFeeRate(nOldFee, txSize);
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CFeeRate nNewFeeRate;
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// The wallet uses a conservative WALLET_INCREMENTAL_RELAY_FEE value to
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// future proof against changes to network wide policy for incremental relay
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// fee that our node may not be aware of.
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CFeeRate walletIncrementalRelayFee = CFeeRate(WALLET_INCREMENTAL_RELAY_FEE);
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if (::incrementalRelayFee > walletIncrementalRelayFee) {
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walletIncrementalRelayFee = ::incrementalRelayFee;
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}
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if (totalFee > 0) {
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CAmount minTotalFee = nOldFeeRate.GetFee(maxNewTxSize) + ::incrementalRelayFee.GetFee(maxNewTxSize);
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if (totalFee < minTotalFee) {
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vErrors.push_back(strprintf("Insufficient totalFee, must be at least %s (oldFee %s + incrementalFee %s)",
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FormatMoney(minTotalFee), FormatMoney(nOldFeeRate.GetFee(maxNewTxSize)), FormatMoney(::incrementalRelayFee.GetFee(maxNewTxSize))));
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currentResult = BumpFeeResult::INVALID_PARAMETER;
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return;
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}
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CAmount requiredFee = CWallet::GetRequiredFee(maxNewTxSize);
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if (totalFee < requiredFee) {
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vErrors.push_back(strprintf("Insufficient totalFee (cannot be less than required fee %s)",
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FormatMoney(requiredFee)));
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currentResult = BumpFeeResult::INVALID_PARAMETER;
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return;
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}
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nNewFee = totalFee;
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nNewFeeRate = CFeeRate(totalFee, maxNewTxSize);
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} else {
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// if user specified a confirm target then don't consider any global payTxFee
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if (specifiedConfirmTarget) {
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nNewFee = CWallet::GetMinimumFee(maxNewTxSize, newConfirmTarget, mempool, ::feeEstimator, true);
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}
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// otherwise use the regular wallet logic to select payTxFee or default confirm target
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else {
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nNewFee = CWallet::GetMinimumFee(maxNewTxSize, newConfirmTarget, mempool, ::feeEstimator);
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}
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nNewFeeRate = CFeeRate(nNewFee, maxNewTxSize);
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// New fee rate must be at least old rate + minimum incremental relay rate
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// walletIncrementalRelayFee.GetFeePerK() should be exact, because it's initialized
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// in that unit (fee per kb).
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// However, nOldFeeRate is a calculated value from the tx fee/size, so
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// add 1 satoshi to the result, because it may have been rounded down.
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if (nNewFeeRate.GetFeePerK() < nOldFeeRate.GetFeePerK() + 1 + walletIncrementalRelayFee.GetFeePerK()) {
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nNewFeeRate = CFeeRate(nOldFeeRate.GetFeePerK() + 1 + walletIncrementalRelayFee.GetFeePerK());
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nNewFee = nNewFeeRate.GetFee(maxNewTxSize);
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}
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}
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// Check that in all cases the new fee doesn't violate maxTxFee
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if (nNewFee > maxTxFee) {
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vErrors.push_back(strprintf("Specified or calculated fee %s is too high (cannot be higher than maxTxFee %s)",
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FormatMoney(nNewFee), FormatMoney(maxTxFee)));
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currentResult = BumpFeeResult::WALLET_ERROR;
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return;
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}
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// check that fee rate is higher than mempool's minimum fee
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// (no point in bumping fee if we know that the new tx won't be accepted to the mempool)
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// This may occur if the user set TotalFee or paytxfee too low, if fallbackfee is too low, or, perhaps,
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// in a rare situation where the mempool minimum fee increased significantly since the fee estimation just a
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// moment earlier. In this case, we report an error to the user, who may use totalFee to make an adjustment.
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CFeeRate minMempoolFeeRate = mempool.GetMinFee(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
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if (nNewFeeRate.GetFeePerK() < minMempoolFeeRate.GetFeePerK()) {
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vErrors.push_back(strprintf("New fee rate (%s) is less than the minimum fee rate (%s) to get into the mempool. totalFee value should to be at least %s or settxfee value should be at least %s to add transaction.", FormatMoney(nNewFeeRate.GetFeePerK()), FormatMoney(minMempoolFeeRate.GetFeePerK()), FormatMoney(minMempoolFeeRate.GetFee(maxNewTxSize)), FormatMoney(minMempoolFeeRate.GetFeePerK())));
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currentResult = BumpFeeResult::WALLET_ERROR;
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return;
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}
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// Now modify the output to increase the fee.
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// If the output is not large enough to pay the fee, fail.
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CAmount nDelta = nNewFee - nOldFee;
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assert(nDelta > 0);
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mtx = *wtx.tx;
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CTxOut* poutput = &(mtx.vout[nOutput]);
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if (poutput->nValue < nDelta) {
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vErrors.push_back("Change output is too small to bump the fee");
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currentResult = BumpFeeResult::WALLET_ERROR;
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return;
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}
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// If the output would become dust, discard it (converting the dust to fee)
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poutput->nValue -= nDelta;
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if (poutput->nValue <= GetDustThreshold(*poutput, ::dustRelayFee)) {
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LogPrint(BCLog::RPC, "Bumping fee and discarding dust output\n");
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nNewFee += poutput->nValue;
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mtx.vout.erase(mtx.vout.begin() + nOutput);
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}
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// Mark new tx not replaceable, if requested.
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if (!newTxReplaceable) {
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for (auto& input : mtx.vin) {
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if (input.nSequence < 0xfffffffe) input.nSequence = 0xfffffffe;
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}
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}
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currentResult = BumpFeeResult::OK;
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}
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bool CFeeBumper::signTransaction(CWallet *pWallet)
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{
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return pWallet->SignTransaction(mtx);
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}
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bool CFeeBumper::commit(CWallet *pWallet)
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{
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AssertLockHeld(pWallet->cs_wallet);
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if (!vErrors.empty() || currentResult != BumpFeeResult::OK) {
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return false;
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}
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if (txid.IsNull() || !pWallet->mapWallet.count(txid)) {
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vErrors.push_back("Invalid or non-wallet transaction id");
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currentResult = BumpFeeResult::MISC_ERROR;
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return false;
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}
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CWalletTx& oldWtx = pWallet->mapWallet[txid];
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// make sure the transaction still has no descendants and hasen't been mined in the meantime
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if (!preconditionChecks(pWallet, oldWtx)) {
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return false;
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}
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CWalletTx wtxBumped(pWallet, MakeTransactionRef(std::move(mtx)));
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// commit/broadcast the tx
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CReserveKey reservekey(pWallet);
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wtxBumped.mapValue = oldWtx.mapValue;
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wtxBumped.mapValue["replaces_txid"] = oldWtx.GetHash().ToString();
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wtxBumped.vOrderForm = oldWtx.vOrderForm;
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wtxBumped.strFromAccount = oldWtx.strFromAccount;
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wtxBumped.fTimeReceivedIsTxTime = true;
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wtxBumped.fFromMe = true;
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CValidationState state;
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if (!pWallet->CommitTransaction(wtxBumped, reservekey, g_connman.get(), state)) {
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// NOTE: CommitTransaction never returns false, so this should never happen.
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vErrors.push_back(strprintf("Error: The transaction was rejected! Reason given: %s", state.GetRejectReason()));
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return false;
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}
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bumpedTxid = wtxBumped.GetHash();
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if (state.IsInvalid()) {
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// This can happen if the mempool rejected the transaction. Report
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// what happened in the "errors" response.
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vErrors.push_back(strprintf("Error: The transaction was rejected: %s", FormatStateMessage(state)));
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}
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// mark the original tx as bumped
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if (!pWallet->MarkReplaced(oldWtx.GetHash(), wtxBumped.GetHash())) {
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// TODO: see if JSON-RPC has a standard way of returning a response
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// along with an exception. It would be good to return information about
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// wtxBumped to the caller even if marking the original transaction
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// replaced does not succeed for some reason.
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vErrors.push_back("Error: Created new bumpfee transaction but could not mark the original transaction as replaced.");
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}
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return true;
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}
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