lnrpc: extract fee limit calculation

lnrpc/marshall_utils.go

@@ -0,0 +1,30 @@
+package lnrpc
+
+import (
+	"github.com/btcsuite/btcutil"
+	"github.com/lightningnetwork/lnd/lnwire"
+)
+
+// CalculateFeeLimit returns the fee limit in millisatoshis. If a percentage
+// based fee limit has been requested, we'll factor in the ratio provided with
+// the amount of the payment.
+func CalculateFeeLimit(feeLimit *FeeLimit,
+	amount lnwire.MilliSatoshi) lnwire.MilliSatoshi {
+
+	switch feeLimit.GetLimit().(type) {
+
+	case *FeeLimit_Fixed:
+		return lnwire.NewMSatFromSatoshis(
+			btcutil.Amount(feeLimit.GetFixed()),
+		)
+
+	case *FeeLimit_Percent:
+		return amount * lnwire.MilliSatoshi(feeLimit.GetPercent()) / 100
+
+	default:
+		// If a fee limit was not specified, we'll use the payment's
+		// amount as an upper bound in order to avoid payment attempts
+		// from incurring fees higher than the payment amount itself.
+		return amount
+	}
+}

lnrpc/routerrpc/router_backend.go

@@ -136,7 +136,7 @@ func (r *RouterBackend) QueryRoutes(ctx context.Context,
 	}
 
 	// Unmarshall restrictions from request.
-	feeLimit := calculateFeeLimit(in.FeeLimit, amtMSat)
+	feeLimit := lnrpc.CalculateFeeLimit(in.FeeLimit, amtMSat)
 
 	ignoredNodes := make(map[route.Vertex]struct{})
 	for _, ignorePubKey := range in.IgnoredNodes {
@@ -308,27 +308,6 @@ func (r *RouterBackend) rpcEdgeToPair(e *lnrpc.EdgeLocator) (
 	return pair, nil
 }
 
-// calculateFeeLimit returns the fee limit in millisatoshis. If a percentage
-// based fee limit has been requested, we'll factor in the ratio provided with
-// the amount of the payment.
-func calculateFeeLimit(feeLimit *lnrpc.FeeLimit,
-	amount lnwire.MilliSatoshi) lnwire.MilliSatoshi {
-
-	switch feeLimit.GetLimit().(type) {
-	case *lnrpc.FeeLimit_Fixed:
-		return lnwire.NewMSatFromSatoshis(
-			btcutil.Amount(feeLimit.GetFixed()),
-		)
-	case *lnrpc.FeeLimit_Percent:
-		return amount * lnwire.MilliSatoshi(feeLimit.GetPercent()) / 100
-	default:
-		// If a fee limit was not specified, we'll use the payment's
-		// amount as an upper bound in order to avoid payment attempts
-		// from incurring fees higher than the payment amount itself.
-		return amount
-	}
-}
-
 // MarshallRoute marshalls an internal route to an rpc route struct.
 func (r *RouterBackend) MarshallRoute(route *route.Route) (*lnrpc.Route, error) {
 	resp := &lnrpc.Route{

rpcserver.go

@@ -2908,27 +2908,6 @@ type rpcPaymentRequest struct {
 	route *route.Route
 }
 
-// calculateFeeLimit returns the fee limit in millisatoshis. If a percentage
-// based fee limit has been requested, we'll factor in the ratio provided with
-// the amount of the payment.
-func calculateFeeLimit(feeLimit *lnrpc.FeeLimit,
-	amount lnwire.MilliSatoshi) lnwire.MilliSatoshi {
-
-	switch feeLimit.GetLimit().(type) {
-	case *lnrpc.FeeLimit_Fixed:
-		return lnwire.NewMSatFromSatoshis(
-			btcutil.Amount(feeLimit.GetFixed()),
-		)
-	case *lnrpc.FeeLimit_Percent:
-		return amount * lnwire.MilliSatoshi(feeLimit.GetPercent()) / 100
-	default:
-		// If a fee limit was not specified, we'll use the payment's
-		// amount as an upper bound in order to avoid payment attempts
-		// from incurring fees higher than the payment amount itself.
-		return amount
-	}
-}
-
 // SendPayment dispatches a bi-directional streaming RPC for sending payments
 // through the Lightning Network. A single RPC invocation creates a persistent
 // bi-directional stream allowing clients to rapidly send payments through the
@@ -3114,7 +3093,7 @@ func extractPaymentIntent(rpcPayReq *rpcPaymentRequest) (rpcPaymentIntent, error
 		}
 
 		// Calculate the fee limit that should be used for this payment.
-		payIntent.feeLimit = calculateFeeLimit(
+		payIntent.feeLimit = lnrpc.CalculateFeeLimit(
 			rpcPayReq.FeeLimit, payIntent.msat,
 		)
 
@@ -3154,7 +3133,7 @@ func extractPaymentIntent(rpcPayReq *rpcPaymentRequest) (rpcPaymentIntent, error
 	)
 
 	// Calculate the fee limit that should be used for this payment.
-	payIntent.feeLimit = calculateFeeLimit(
+	payIntent.feeLimit = lnrpc.CalculateFeeLimit(
 		rpcPayReq.FeeLimit, payIntent.msat,
 	)