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-rw-r--r--src/wallet/feebumper.cpp275
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diff --git a/src/wallet/feebumper.cpp b/src/wallet/feebumper.cpp
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+// Copyright (c) 2017 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "consensus/validation.h"
+#include "wallet/feebumper.h"
+#include "wallet/wallet.h"
+#include "policy/policy.h"
+#include "policy/rbf.h"
+#include "validation.h" //for mempool access
+#include "txmempool.h"
+#include "utilmoneystr.h"
+#include "util.h"
+#include "net.h"
+
+// Calculate the size of the transaction assuming all signatures are max size
+// Use DummySignatureCreator, which inserts 72 byte signatures everywhere.
+// TODO: re-use this in CWallet::CreateTransaction (right now
+// CreateTransaction uses the constructed dummy-signed tx to do a priority
+// calculation, but we should be able to refactor after priority is removed).
+// NOTE: this requires that all inputs must be in mapWallet (eg the tx should
+// be IsAllFromMe).
+int64_t CalculateMaximumSignedTxSize(const CWallet *pWallet, const CTransaction &tx)
+{
+ CMutableTransaction txNew(tx);
+ std::vector<std::pair<const CWalletTx *, unsigned int>> vCoins;
+ // Look up the inputs. We should have already checked that this transaction
+ // IsAllFromMe(ISMINE_SPENDABLE), so every input should already be in our
+ // wallet, with a valid index into the vout array.
+ for (auto& input : tx.vin) {
+ const auto mi = pWallet->mapWallet.find(input.prevout.hash);
+ assert(mi != pWallet->mapWallet.end() && input.prevout.n < mi->second.tx->vout.size());
+ vCoins.emplace_back(std::make_pair(&(mi->second), input.prevout.n));
+ }
+ if (!pWallet->DummySignTx(txNew, vCoins)) {
+ // This should never happen, because IsAllFromMe(ISMINE_SPENDABLE)
+ // implies that we can sign for every input.
+ return -1;
+ }
+ return GetVirtualTransactionSize(txNew);
+}
+
+CFeeBumper::CFeeBumper(const CWallet *pWallet, const uint256 txidIn, int newConfirmTarget, bool specifiedConfirmTarget, CAmount totalFee, bool newTxReplaceable)
+ :
+ txid(txidIn),
+ nOldFee(0),
+ nNewFee(0)
+{
+ vErrors.clear();
+ bumpedTxid.SetNull();
+ AssertLockHeld(pWallet->cs_wallet);
+ if (!pWallet->mapWallet.count(txid)) {
+ vErrors.push_back("Invalid or non-wallet transaction id");
+ currentResult = BumpFeeResult::INVALID_ADDRESS_OR_KEY;
+ return;
+ }
+ auto it = pWallet->mapWallet.find(txid);
+ const CWalletTx& wtx = it->second;
+
+ if (pWallet->HasWalletSpend(txid)) {
+ vErrors.push_back("Transaction has descendants in the wallet");
+ currentResult = BumpFeeResult::INVALID_PARAMETER;
+ return;
+ }
+
+ {
+ LOCK(mempool.cs);
+ auto it_mp = mempool.mapTx.find(txid);
+ if (it_mp != mempool.mapTx.end() && it_mp->GetCountWithDescendants() > 1) {
+ vErrors.push_back("Transaction has descendants in the mempool");
+ currentResult = BumpFeeResult::INVALID_PARAMETER;
+ return;
+ }
+ }
+
+ if (wtx.GetDepthInMainChain() != 0) {
+ vErrors.push_back("Transaction has been mined, or is conflicted with a mined transaction");
+ currentResult = BumpFeeResult::WALLET_ERROR;
+ return;
+ }
+
+ if (!SignalsOptInRBF(wtx)) {
+ vErrors.push_back("Transaction is not BIP 125 replaceable");
+ currentResult = BumpFeeResult::WALLET_ERROR;
+ return;
+ }
+
+ if (wtx.mapValue.count("replaced_by_txid")) {
+ vErrors.push_back(strprintf("Cannot bump transaction %s which was already bumped by transaction %s", txid.ToString(), wtx.mapValue.at("replaced_by_txid")));
+ currentResult = BumpFeeResult::WALLET_ERROR;
+ return;
+ }
+
+ // check that original tx consists entirely of our inputs
+ // 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)
+ if (!pWallet->IsAllFromMe(wtx, ISMINE_SPENDABLE)) {
+ vErrors.push_back("Transaction contains inputs that don't belong to this wallet");
+ currentResult = BumpFeeResult::WALLET_ERROR;
+ return;
+ }
+
+ // figure out which output was change
+ // if there was no change output or multiple change outputs, fail
+ int nOutput = -1;
+ for (size_t i = 0; i < wtx.tx->vout.size(); ++i) {
+ if (pWallet->IsChange(wtx.tx->vout[i])) {
+ if (nOutput != -1) {
+ vErrors.push_back("Transaction has multiple change outputs");
+ currentResult = BumpFeeResult::WALLET_ERROR;
+ return;
+ }
+ nOutput = i;
+ }
+ }
+ if (nOutput == -1) {
+ vErrors.push_back("Transaction does not have a change output");
+ currentResult = BumpFeeResult::WALLET_ERROR;
+ return;
+ }
+
+ // Calculate the expected size of the new transaction.
+ int64_t txSize = GetVirtualTransactionSize(*(wtx.tx));
+ const int64_t maxNewTxSize = CalculateMaximumSignedTxSize(pWallet, *wtx.tx);
+ if (maxNewTxSize < 0) {
+ vErrors.push_back("Transaction contains inputs that cannot be signed");
+ currentResult = BumpFeeResult::INVALID_ADDRESS_OR_KEY;
+ return;
+ }
+
+ // calculate the old fee and fee-rate
+ nOldFee = wtx.GetDebit(ISMINE_SPENDABLE) - wtx.tx->GetValueOut();
+ CFeeRate nOldFeeRate(nOldFee, txSize);
+ CFeeRate nNewFeeRate;
+ // The wallet uses a conservative WALLET_INCREMENTAL_RELAY_FEE value to
+ // future proof against changes to network wide policy for incremental relay
+ // fee that our node may not be aware of.
+ CFeeRate walletIncrementalRelayFee = CFeeRate(WALLET_INCREMENTAL_RELAY_FEE);
+ if (::incrementalRelayFee > walletIncrementalRelayFee) {
+ walletIncrementalRelayFee = ::incrementalRelayFee;
+ }
+
+ if (totalFee > 0) {
+ CAmount minTotalFee = nOldFeeRate.GetFee(maxNewTxSize) + ::incrementalRelayFee.GetFee(maxNewTxSize);
+ if (totalFee < minTotalFee) {
+ vErrors.push_back(strprintf("Insufficient totalFee, must be at least %s (oldFee %s + incrementalFee %s)",
+ FormatMoney(minTotalFee), FormatMoney(nOldFeeRate.GetFee(maxNewTxSize)), FormatMoney(::incrementalRelayFee.GetFee(maxNewTxSize))));
+ currentResult = BumpFeeResult::INVALID_PARAMETER;
+ return;
+ }
+ CAmount requiredFee = pWallet->GetRequiredFee(maxNewTxSize);
+ if (totalFee < requiredFee) {
+ vErrors.push_back(strprintf("Insufficient totalFee (cannot be less than required fee %s)",
+ FormatMoney(requiredFee)));
+ currentResult = BumpFeeResult::INVALID_PARAMETER;
+ return;
+ }
+ nNewFee = totalFee;
+ nNewFeeRate = CFeeRate(totalFee, maxNewTxSize);
+ } else {
+ // if user specified a confirm target then don't consider any global payTxFee
+ if (specifiedConfirmTarget) {
+ nNewFee = pWallet->GetMinimumFee(maxNewTxSize, newConfirmTarget, mempool, CAmount(0));
+ }
+ // otherwise use the regular wallet logic to select payTxFee or default confirm target
+ else {
+ nNewFee = pWallet->GetMinimumFee(maxNewTxSize, newConfirmTarget, mempool);
+ }
+
+ nNewFeeRate = CFeeRate(nNewFee, maxNewTxSize);
+
+ // New fee rate must be at least old rate + minimum incremental relay rate
+ // walletIncrementalRelayFee.GetFeePerK() should be exact, because it's initialized
+ // in that unit (fee per kb).
+ // However, nOldFeeRate is a calculated value from the tx fee/size, so
+ // add 1 satoshi to the result, because it may have been rounded down.
+ if (nNewFeeRate.GetFeePerK() < nOldFeeRate.GetFeePerK() + 1 + walletIncrementalRelayFee.GetFeePerK()) {
+ nNewFeeRate = CFeeRate(nOldFeeRate.GetFeePerK() + 1 + walletIncrementalRelayFee.GetFeePerK());
+ nNewFee = nNewFeeRate.GetFee(maxNewTxSize);
+ }
+ }
+
+ // Check that in all cases the new fee doesn't violate maxTxFee
+ if (nNewFee > maxTxFee) {
+ vErrors.push_back(strprintf("Specified or calculated fee %s is too high (cannot be higher than maxTxFee %s)",
+ FormatMoney(nNewFee), FormatMoney(maxTxFee)));
+ currentResult = BumpFeeResult::WALLET_ERROR;
+ return;
+ }
+
+ // check that fee rate is higher than mempool's minimum fee
+ // (no point in bumping fee if we know that the new tx won't be accepted to the mempool)
+ // This may occur if the user set TotalFee or paytxfee too low, if fallbackfee is too low, or, perhaps,
+ // in a rare situation where the mempool minimum fee increased significantly since the fee estimation just a
+ // moment earlier. In this case, we report an error to the user, who may use totalFee to make an adjustment.
+ CFeeRate minMempoolFeeRate = mempool.GetMinFee(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
+ if (nNewFeeRate.GetFeePerK() < minMempoolFeeRate.GetFeePerK()) {
+ 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())));
+ currentResult = BumpFeeResult::WALLET_ERROR;
+ return;
+ }
+
+ // Now modify the output to increase the fee.
+ // If the output is not large enough to pay the fee, fail.
+ CAmount nDelta = nNewFee - nOldFee;
+ assert(nDelta > 0);
+ mtx = *wtx.tx;
+ CTxOut* poutput = &(mtx.vout[nOutput]);
+ if (poutput->nValue < nDelta) {
+ vErrors.push_back("Change output is too small to bump the fee");
+ currentResult = BumpFeeResult::WALLET_ERROR;
+ return;
+ }
+
+ // If the output would become dust, discard it (converting the dust to fee)
+ poutput->nValue -= nDelta;
+ if (poutput->nValue <= poutput->GetDustThreshold(::dustRelayFee)) {
+ LogPrint(BCLog::RPC, "Bumping fee and discarding dust output\n");
+ nNewFee += poutput->nValue;
+ mtx.vout.erase(mtx.vout.begin() + nOutput);
+ }
+
+ // Mark new tx not replaceable, if requested.
+ if (!newTxReplaceable) {
+ for (auto& input : mtx.vin) {
+ if (input.nSequence < 0xfffffffe) input.nSequence = 0xfffffffe;
+ }
+ }
+
+ currentResult = BumpFeeResult::OK;
+}
+
+bool CFeeBumper::commit(CWallet *pWallet)
+{
+ AssertLockHeld(pWallet->cs_wallet);
+ vErrors.clear();
+ if (txid.IsNull() || !pWallet->mapWallet.count(txid)) {
+ vErrors.push_back("Invalid or non-wallet transaction id");
+ currentResult = BumpFeeResult::MISC_ERROR;
+ }
+ CWalletTx& oldWtx = pWallet->mapWallet[txid];
+
+ CWalletTx wtxBumped(pWallet, MakeTransactionRef(std::move(mtx)));
+ // commit/broadcast the tx
+ CReserveKey reservekey(pWallet);
+ wtxBumped.mapValue = oldWtx.mapValue;
+ wtxBumped.mapValue["replaces_txid"] = oldWtx.GetHash().ToString();
+ wtxBumped.vOrderForm = oldWtx.vOrderForm;
+ wtxBumped.strFromAccount = oldWtx.strFromAccount;
+ wtxBumped.fTimeReceivedIsTxTime = true;
+ wtxBumped.fFromMe = true;
+ CValidationState state;
+ if (!pWallet->CommitTransaction(wtxBumped, reservekey, g_connman.get(), state)) {
+ // NOTE: CommitTransaction never returns false, so this should never happen.
+ vErrors.push_back(strprintf("Error: The transaction was rejected! Reason given: %s", state.GetRejectReason()));
+ return false;
+ }
+
+ bumpedTxid = wtxBumped.GetHash();
+ if (state.IsInvalid()) {
+ // This can happen if the mempool rejected the transaction. Report
+ // what happened in the "errors" response.
+ vErrors.push_back(strprintf("Error: The transaction was rejected: %s", FormatStateMessage(state)));
+ }
+
+ // mark the original tx as bumped
+ if (!pWallet->MarkReplaced(oldWtx.GetHash(), wtxBumped.GetHash())) {
+ // TODO: see if JSON-RPC has a standard way of returning a response
+ // along with an exception. It would be good to return information about
+ // wtxBumped to the caller even if marking the original transaction
+ // replaced does not succeed for some reason.
+ vErrors.push_back("Error: Created new bumpfee transaction but could not mark the original transaction as replaced.");
+ }
+ return true;
+}
+