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generalize bumpfee to add inputs when needed

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This commit is contained in:
Gregory Sanders
2019-03-06 16:30:00 -05:00
parent c536dfbcb0
commit 0ea47ba7b3
6 changed files with 153 additions and 43 deletions
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155
src/wallet/feebumper.cpp
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@@ -75,9 +75,11 @@ bool TransactionCanBeBumped(const CWallet* wallet, const uint256& txid)
return res == feebumper::Result::OK;
}
Result CreateTransaction(const CWallet* wallet, const uint256& txid, const CCoinControl& coin_control, CAmount total_fee, std::vector<std::string>& errors,
CAmount& old_fee, CAmount& new_fee, CMutableTransaction& mtx)
Result CreateTotalBumpTransaction(const CWallet* wallet, const uint256& txid, const CCoinControl& coin_control, CAmount total_fee, std::vector<std::string>& errors,
CAmount& old_fee, CAmount& new_fee, CMutableTransaction& mtx)
{
new_fee = total_fee;
auto locked_chain = wallet->chain().lock();
LOCK(wallet->cs_wallet);
errors.clear();
@@ -121,7 +123,6 @@ Result CreateTransaction(const CWallet* wallet, const uint256& txid, const CCoin
// calculate the old fee and fee-rate
old_fee = wtx.GetDebit(ISMINE_SPENDABLE) - wtx.tx->GetValueOut();
CFeeRate nOldFeeRate(old_fee, 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.
@@ -131,34 +132,17 @@ Result CreateTransaction(const CWallet* wallet, const uint256& txid, const CCoin
walletIncrementalRelayFee = nodeIncrementalRelayFee;
}
if (total_fee > 0) {
CAmount minTotalFee = nOldFeeRate.GetFee(maxNewTxSize) + nodeIncrementalRelayFee.GetFee(maxNewTxSize);
if (total_fee < minTotalFee) {
errors.push_back(strprintf("Insufficient totalFee, must be at least %s (oldFee %s + incrementalFee %s)",
FormatMoney(minTotalFee), FormatMoney(nOldFeeRate.GetFee(maxNewTxSize)), FormatMoney(nodeIncrementalRelayFee.GetFee(maxNewTxSize))));
return Result::INVALID_PARAMETER;
}
CAmount requiredFee = GetRequiredFee(*wallet, maxNewTxSize);
if (total_fee < requiredFee) {
errors.push_back(strprintf("Insufficient totalFee (cannot be less than required fee %s)",
FormatMoney(requiredFee)));
return Result::INVALID_PARAMETER;
}
new_fee = total_fee;
nNewFeeRate = CFeeRate(total_fee, maxNewTxSize);
} else {
new_fee = GetMinimumFee(*wallet, maxNewTxSize, coin_control, nullptr /* FeeCalculation */);
nNewFeeRate = CFeeRate(new_fee, 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());
new_fee = nNewFeeRate.GetFee(maxNewTxSize);
}
CAmount minTotalFee = nOldFeeRate.GetFee(maxNewTxSize) + nodeIncrementalRelayFee.GetFee(maxNewTxSize);
if (total_fee < minTotalFee) {
errors.push_back(strprintf("Insufficient totalFee, must be at least %s (oldFee %s + incrementalFee %s)",
FormatMoney(minTotalFee), FormatMoney(nOldFeeRate.GetFee(maxNewTxSize)), FormatMoney(nodeIncrementalRelayFee.GetFee(maxNewTxSize))));
return Result::INVALID_PARAMETER;
}
CAmount requiredFee = GetRequiredFee(*wallet, maxNewTxSize);
if (total_fee < requiredFee) {
errors.push_back(strprintf("Insufficient totalFee (cannot be less than required fee %s)",
FormatMoney(requiredFee)));
return Result::INVALID_PARAMETER;
}
// Check that in all cases the new fee doesn't violate maxTxFee
@@ -175,14 +159,14 @@ Result CreateTransaction(const CWallet* wallet, const uint256& txid, const CCoin
// 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 total_fee to make an adjustment.
CFeeRate minMempoolFeeRate = wallet->chain().mempoolMinFee();
CFeeRate nNewFeeRate = CFeeRate(total_fee, maxNewTxSize);
if (nNewFeeRate.GetFeePerK() < minMempoolFeeRate.GetFeePerK()) {
errors.push_back(strprintf(
"New fee rate (%s) is lower than the minimum fee rate (%s) to get into the mempool -- "
"the totalFee value should be at least %s or the settxfee value should be at least %s to add transaction",
"the totalFee value should be at least %s to add transaction",
FormatMoney(nNewFeeRate.GetFeePerK()),
FormatMoney(minMempoolFeeRate.GetFeePerK()),
FormatMoney(minMempoolFeeRate.GetFee(maxNewTxSize)),
FormatMoney(minMempoolFeeRate.GetFeePerK())));
FormatMoney(minMempoolFeeRate.GetFee(maxNewTxSize))));
return Result::WALLET_ERROR;
}
@@ -212,6 +196,109 @@ Result CreateTransaction(const CWallet* wallet, const uint256& txid, const CCoin
}
}
return Result::OK;
}
Result CreateRateBumpTransaction(CWallet* wallet, const uint256& txid, const CCoinControl& coin_control, std::vector<std::string>& errors,
CAmount& old_fee, CAmount& new_fee, CMutableTransaction& mtx)
{
// We are going to modify coin control later, copy to re-use
CCoinControl new_coin_control(coin_control);
auto locked_chain = wallet->chain().lock();
LOCK(wallet->cs_wallet);
errors.clear();
auto it = wallet->mapWallet.find(txid);
if (it == wallet->mapWallet.end()) {
errors.push_back("Invalid or non-wallet transaction id");
return Result::INVALID_ADDRESS_OR_KEY;
}
const CWalletTx& wtx = it->second;
Result result = PreconditionChecks(*locked_chain, wallet, wtx, errors);
if (result != Result::OK) {
return result;
}
// Fill in recipients(and preserve a single change key if there is one)
std::vector<CRecipient> recipients;
for (const auto& output : wtx.tx->vout) {
if (!wallet->IsChange(output)) {
CRecipient recipient = {output.scriptPubKey, output.nValue, false};
recipients.push_back(recipient);
} else {
CTxDestination change_dest;
ExtractDestination(output.scriptPubKey, change_dest);
new_coin_control.destChange = change_dest;
}
}
// Get the fee rate of the original transaction. This is calculated from
// the tx fee/vsize, so it may have been rounded down. Add 1 satoshi to the
// result.
old_fee = wtx.GetDebit(ISMINE_SPENDABLE) - wtx.tx->GetValueOut();
int64_t txSize = GetVirtualTransactionSize(*(wtx.tx));
// Feerate of thing we are bumping
CFeeRate feerate(old_fee, txSize);
feerate += CFeeRate(1);
// The node has a configurable incremental relay fee. Increment the fee by
// the minimum of that and the wallet's 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. This ensures we're over the over the required relay fee rate
// (BIP 125 rule 4). The replacement tx will be at least as large as the
// original tx, so the total fee will be greater (BIP 125 rule 3)
CFeeRate node_incremental_relay_fee = wallet->chain().relayIncrementalFee();
CFeeRate wallet_incremental_relay_fee = CFeeRate(WALLET_INCREMENTAL_RELAY_FEE);
feerate += std::max(node_incremental_relay_fee, wallet_incremental_relay_fee);
// Fee rate must also be at least the wallet's GetMinimumFeeRate
CFeeRate min_feerate(GetMinimumFeeRate(*wallet, new_coin_control, /* feeCalc */ nullptr));
// Set the required fee rate for the replacement transaction in coin control.
new_coin_control.m_feerate = std::max(feerate, min_feerate);
// Fill in required inputs we are double-spending(all of them)
// N.B.: bip125 doesn't require all the inputs in the replaced transaction to be
// used in the replacement transaction, but it's very important for wallets to make
// sure that happens. If not, it would be possible to bump a transaction A twice to
// A2 and A3 where A2 and A3 don't conflict (or alternatively bump A to A2 and A2
// to A3 where A and A3 don't conflict). If both later get confirmed then the sender
// has accidentally double paid.
for (const auto& inputs : wtx.tx->vin) {
new_coin_control.Select(COutPoint(inputs.prevout));
}
new_coin_control.fAllowOtherInputs = true;
// We cannot source new unconfirmed inputs(bip125 rule 2)
new_coin_control.m_min_depth = 1;
CTransactionRef tx_new = MakeTransactionRef();
CReserveKey reservekey(wallet);
CAmount fee_ret;
int change_pos_in_out = -1; // No requested location for change
std::string fail_reason;
if (!wallet->CreateTransaction(*locked_chain, recipients, tx_new, reservekey, fee_ret, change_pos_in_out, fail_reason, new_coin_control, false)) {
errors.push_back("Unable to create transaction: " + fail_reason);
return Result::WALLET_ERROR;
}
// If change key hasn't been ReturnKey'ed by this point, we take it out of keypool
reservekey.KeepKey();
// Write back new fee if successful
new_fee = fee_ret;
// Write back transaction
mtx = CMutableTransaction(*tx_new);
// Mark new tx not replaceable, if requested.
if (!coin_control.m_signal_bip125_rbf.get_value_or(wallet->m_signal_rbf)) {
for (auto& input : mtx.vin) {
if (input.nSequence < 0xfffffffe) input.nSequence = 0xfffffffe;
}
}
return Result::OK;
}