lnwallet+lnrpc: parameterize chanfunding fee sanity check

lightningnetwork · Mar 28, 2024 · 0e83ed6 · 0e83ed6
1 parent d3e5b2f
commit 0e83ed6
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Showing 4 changed files with 23 additions and 16 deletions.
diff --git a/lnrpc/walletrpc/walletkit_server.go b/lnrpc/walletrpc/walletkit_server.go
@@ -1546,7 +1546,7 @@ func (w *WalletKit) fundPsbtCoinSelect(account string, changeIndex int32,
 
 		changeAmt, needMore, err := chanfunding.CalculateChangeAmount(
 			inputSum, outputSum, packetFeeNoChange,
-			packetFeeWithChange, changeDustLimit, changeType,
+			packetFeeWithChange, changeDustLimit, changeType, true,
 		)
 		if err != nil {
 			return nil, fmt.Errorf("error calculating change "+
@@ -1604,6 +1604,7 @@ func (w *WalletKit) fundPsbtCoinSelect(account string, changeIndex int32,
 		selectedCoins, changeAmount, err := chanfunding.CoinSelect(
 			feeRate, fundingAmount, changeDustLimit, coins,
 			w.cfg.CoinSelectionStrategy, estimator, changeType,
+			true,
 		)
 		if err != nil {
 			return fmt.Errorf("error selecting coins: %w", err)

diff --git a/lnwallet/chanfunding/coin_select.go b/lnwallet/chanfunding/coin_select.go
@@ -163,7 +163,8 @@ func sanityCheckFee(totalOut, fee btcutil.Amount) error {
 func CoinSelect(feeRate chainfee.SatPerKWeight, amt, dustLimit btcutil.Amount,
 	coins []wallet.Coin, strategy wallet.CoinSelectionStrategy,
 	existingWeight input.TxWeightEstimator,
-	changeType ChangeAddressType) ([]wallet.Coin, btcutil.Amount, error) {
+	changeType ChangeAddressType, skipFeeCheck bool) ([]wallet.Coin,
+	btcutil.Amount, error) {
 
 	amtNeeded := amt
 	for {
@@ -188,6 +189,7 @@ func CoinSelect(feeRate chainfee.SatPerKWeight, amt, dustLimit btcutil.Amount,
 		changeAmount, newAmtNeeded, err := CalculateChangeAmount(
 			totalSat, amt, requiredFeeNoChange,
 			requiredFeeWithChange, dustLimit, changeType,
+			skipFeeCheck,
 		)
 		if err != nil {
 			return nil, 0, err
@@ -216,7 +218,8 @@ func CoinSelect(feeRate chainfee.SatPerKWeight, amt, dustLimit btcutil.Amount,
 // fees and that more coins need to be selected.
 func CalculateChangeAmount(totalInputAmt, requiredAmt, requiredFeeNoChange,
 	requiredFeeWithChange, dustLimit btcutil.Amount,
-	changeType ChangeAddressType) (btcutil.Amount, btcutil.Amount, error) {
+	changeType ChangeAddressType, skipFeeCheck bool) (btcutil.Amount,
+	btcutil.Amount, error) {
 
 	// This is just a sanity check to make sure the function is used
 	// correctly.
@@ -263,12 +266,15 @@ func CalculateChangeAmount(totalInputAmt, requiredAmt, requiredFeeNoChange,
 		changeAmt = 0
 	}
 
-	// Sanity check the resulting output values to make sure we
-	// don't burn a great part to fees.
-	totalOut := requiredAmt + changeAmt
-	err := sanityCheckFee(totalOut, totalInputAmt-totalOut)
-	if err != nil {
-		return 0, 0, err
+	if !skipFeeCheck {
+		// Sanity check the resulting output values to make sure we
+		// don't burn a great part to fees.
+		totalOut := requiredAmt + changeAmt
+
+		err := sanityCheckFee(totalOut, totalInputAmt-totalOut)
+		if err != nil {
+			return 0, 0, err
+		}
 	}
 
 	return changeAmt, 0, nil
@@ -347,8 +353,8 @@ func CoinSelectUpToAmount(feeRate chainfee.SatPerKWeight, minAmount, maxAmount,
 	reserved, dustLimit btcutil.Amount, coins []wallet.Coin,
 	strategy wallet.CoinSelectionStrategy,
 	existingWeight input.TxWeightEstimator,
-	changeType ChangeAddressType) ([]wallet.Coin, btcutil.Amount,
-	btcutil.Amount, error) {
+	changeType ChangeAddressType, skipFeeCheck bool) ([]wallet.Coin,
+	btcutil.Amount, btcutil.Amount, error) {
 
 	var (
 		// selectSubtractFee is tracking if our coin selection was
@@ -369,7 +375,7 @@ func CoinSelectUpToAmount(feeRate chainfee.SatPerKWeight, minAmount, maxAmount,
 	// maxAmount with or without a change output that covers the miner fee.
 	selected, changeAmt, err := CoinSelect(
 		feeRate, maxAmount, dustLimit, coins, strategy, existingWeight,
-		changeType,
+		changeType, skipFeeCheck,
 	)
 
 	var errInsufficientFunds *ErrInsufficientFunds

diff --git a/lnwallet/chanfunding/coin_select_test.go b/lnwallet/chanfunding/coin_select_test.go
@@ -316,7 +316,7 @@ func TestCoinSelect(t *testing.T) {
 			selected, changeAmt, err := CoinSelect(
 				feeRate, test.outputValue, dustLimit,
 				test.coins, wallet.CoinSelectionLargest,
-				fundingOutputEstimate, test.changeType,
+				fundingOutputEstimate, test.changeType, false,
 			)
 
 			if test.expectErr {
@@ -871,7 +871,7 @@ func TestCoinSelectUpToAmount(t *testing.T) {
 				test.reserved, dustLimit, test.coins,
 				wallet.CoinSelectionLargest,
 				fundingOutputEstimate,
-				defaultChanFundingChangeType,
+				defaultChanFundingChangeType, false,
 			)
 			if len(test.expectErr) == 0 && err != nil {
 				t.Fatalf(err.Error())

diff --git a/lnwallet/chanfunding/wallet_assembler.go b/lnwallet/chanfunding/wallet_assembler.go
@@ -435,7 +435,7 @@ func (w *WalletAssembler) ProvisionChannel(r *Request) (Intent, error) {
 				r.FeeRate, r.MinFundAmt, r.FundUpToMaxAmt,
 				reserve, w.cfg.DustLimit, coins,
 				w.cfg.CoinSelectionStrategy,
-				fundingOutputWeight, changeType,
+				fundingOutputWeight, changeType, false,
 			)
 			if err != nil {
 				return err
@@ -484,7 +484,7 @@ func (w *WalletAssembler) ProvisionChannel(r *Request) (Intent, error) {
 			selectedCoins, changeAmt, err = CoinSelect(
 				r.FeeRate, r.LocalAmt, dustLimit, coins,
 				w.cfg.CoinSelectionStrategy,
-				fundingOutputWeight, changeType,
+				fundingOutputWeight, changeType, false,
 			)
 			if err != nil {
 				return err