wallet/feebumper.h \

wallet/feebumper.cpp \

typedef std::shared_ptr<CMutableTransaction> CMutableTransactionRef;

static inline CMutableTransactionRef MakeMutableTransactionRef(const CTransactionRef& txRef) { return std::make_shared<CMutableTransaction>(*txRef); }

#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"

int64_t CalculateMaximumSignedTxSize(const CTransaction &tx)

{

CMutableTransaction txNew(tx);

std::vector<std::pair<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 = pwalletMain->mapWallet.find(input.prevout.hash);

assert(mi != pwalletMain->mapWallet.end() && input.prevout.n < mi->second.tx->vout.size());

vCoins.emplace_back(std::make_pair(&(mi->second), input.prevout.n));

}

if (!pwalletMain->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),

mtx(0),

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 = CFeeBumper::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 = CFeeBumper::BumpFeeResult::MISC_ERROR;

return;

}

{

LOCK(mempool.cs);

auto it = mempool.mapTx.find(txid);

if (it != mempool.mapTx.end() && it->GetCountWithDescendants() > 1) {

vErrors.push_back("Transaction has descendants in the mempool");

currentResult = CFeeBumper::BumpFeeResult::MISC_ERROR;

return;

}

}

if (wtx.GetDepthInMainChain() != 0) {

vErrors.push_back("Transaction has been mined, or is conflicted with a mined transaction");

currentResult = CFeeBumper::BumpFeeResult::INVALID_ADDRESS_OR_KEY;

return;

}

if (!SignalsOptInRBF(wtx)) {

vErrors.push_back("Transaction is not BIP 125 replaceable");

currentResult = CFeeBumper::BumpFeeResult::INVALID_ADDRESS_OR_KEY;

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 = CFeeBumper::BumpFeeResult::INVALID_REQUEST;

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 = CFeeBumper::BumpFeeResult::INVALID_ADDRESS_OR_KEY;

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 = CFeeBumper::BumpFeeResult::MISC_ERROR;

return;

}

nOutput = i;

}

}

if (nOutput == -1) {

vErrors.push_back("Transaction does not have a change output");

currentResult = CFeeBumper::BumpFeeResult::MISC_ERROR;

return;

}

// Calculate the expected size of the new transaction.

int64_t txSize = GetVirtualTransactionSize(*(wtx.tx));

const int64_t maxNewTxSize = CalculateMaximumSignedTxSize(*wtx.tx);

if (maxNewTxSize < 0) {

vErrors.push_back("Transaction contains inputs that cannot be signed");

currentResult = CFeeBumper::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 = CFeeBumper::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 = CFeeBumper::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 = CFeeBumper::BumpFeeResult::MISC_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 = CFeeBumper::BumpFeeResult::MISC_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 = MakeMutableTransactionRef(wtx.tx);

CTxOut* poutput = &(mtx->vout[nOutput]);

if (poutput->nValue < nDelta) {

vErrors.push_back("Change output is too small to bump the fee");

currentResult = CFeeBumper::BumpFeeResult::MISC_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("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 = CFeeBumper::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;

}

#ifndef BITCOIN_WALLET_FEEBUMPER_H

#define BITCOIN_WALLET_FEEBUMPER_H

#include <primitives/transaction.h>

class CWallet;

class uint256;

class CFeeBumper

{

enum class BumpFeeResult

{

OK,

INVALID_ADDRESS_OR_KEY,

INVALID_REQUEST,

INVALID_PARAMETER,

MISC_ERROR,

};

CFeeBumper(const CWallet *pWalletIn, const uint256 txidIn, int newConfirmTarget, bool specifiedConfirmTarget, CAmount totalFee, bool newTxReplaceable);

CFeeBumper::BumpFeeResult getResult() const { return currentResult; }

const std::vector<std::string>& getErrors() const { return vErrors; }

CAmount getOldFee() const { return nOldFee; }

CAmount getNewFee() const { return nNewFee; }

CMutableTransactionRef getBumpedTxRef() const { return mtx; }

uint256 getBumpedTxId() const { return bumpedTxid; }

bool commit(CWallet *pWalletNonConst);

const uint256 txid;

uint256 bumpedTxid;

CMutableTransactionRef mtx;

std::vector<std::string> vErrors;

BumpFeeResult currentResult;

CAmount nOldFee;

CAmount nNewFee;

};

#endif // BITCOIN_WALLET_FEEBUMPER_H