routing/route+multi: remove redundant TotalFees field

Instead get it on demand using method TotalFees().

channeldb/payments.go

@@ -361,7 +361,7 @@ func deserializeHop(r io.Reader) (*route.Hop, error) {
 
 func serializeRoute(w io.Writer, r route.Route) error {
 	if err := WriteElements(w,
-		r.TotalTimeLock, r.TotalFees, r.TotalAmount, r.SourcePubKey[:],
+		r.TotalTimeLock, r.TotalAmount, r.SourcePubKey[:],
 	); err != nil {
 		return err
 	}
@@ -382,7 +382,7 @@ func serializeRoute(w io.Writer, r route.Route) error {
 func deserializeRoute(r io.Reader) (route.Route, error) {
 	rt := route.Route{}
 	if err := ReadElements(r,
-		&rt.TotalTimeLock, &rt.TotalFees, &rt.TotalAmount,
+		&rt.TotalTimeLock, &rt.TotalAmount,
 	); err != nil {
 		return rt, err
 	}

channeldb/payments_test.go

@@ -27,7 +27,6 @@ var (
 
 	testRoute = route.Route{
 		TotalTimeLock: 123,
-		TotalFees:     999,
 		TotalAmount:   1234567,
 		SourcePubKey:  route.NewVertex(pub),
 		Hops: []*route.Hop{

lnrpc/routerrpc/router_backend.go

@@ -185,8 +185,8 @@ func calculateFeeLimit(feeLimit *lnrpc.FeeLimit,
 func (r *RouterBackend) MarshallRoute(route *route.Route) *lnrpc.Route {
 	resp := &lnrpc.Route{
 		TotalTimeLock: route.TotalTimeLock,
-		TotalFees:     int64(route.TotalFees.ToSatoshis()),
-		TotalFeesMsat: int64(route.TotalFees),
+		TotalFees:     int64(route.TotalFees().ToSatoshis()),
+		TotalFeesMsat: int64(route.TotalFees()),
 		TotalAmt:      int64(route.TotalAmount.ToSatoshis()),
 		TotalAmtMsat:  int64(route.TotalAmount),
 		Hops:          make([]*lnrpc.Hop, len(route.Hops)),

lnrpc/routerrpc/router_backend_test.go

@@ -55,8 +55,6 @@ func TestQueryRoutes(t *testing.T) {
 		}},
 	}
 
-	rt := &route.Route{}
-
 	findRoute := func(source, target route.Vertex,
 		amt lnwire.MilliSatoshi, restrictions *routing.RestrictParams,
 		finalExpiry ...uint16) (*route.Route, error) {
@@ -95,7 +93,8 @@ func TestQueryRoutes(t *testing.T) {
 			t.Fatal("unexpected ignored node")
 		}
 
-		return rt, nil
+		hops := []*route.Hop{&route.Hop{}}
+		return route.NewRouteFromHops(amt, 144, source, hops)
 	}
 
 	backend := &RouterBackend{

lnrpc/routerrpc/router_server.go

@@ -269,7 +269,7 @@ func (s *Server) EstimateRouteFee(ctx context.Context,
 	}
 
 	return &RouteFeeResponse{
-		RoutingFeeMsat: int64(route.TotalFees),
+		RoutingFeeMsat: int64(route.TotalFees()),
 		TimeLockDelay:  int64(route.TotalTimeLock),
 	}, nil
 }

routing/route/route.go

@@ -69,11 +69,6 @@ type Route struct {
 	// the payment preimage to complete the payment.
 	TotalTimeLock uint32
 
-	// TotalFees is the sum of the fees paid at each hop within the final
-	// route. In the case of a one-hop payment, this value will be zero as
-	// we don't need to pay a fee to ourself.
-	TotalFees lnwire.MilliSatoshi
-
 	// TotalAmount is the total amount of funds required to complete a
 	// payment over this route. This value includes the cumulative fees at
 	// each hop. As a result, the HTLC extended to the first-hop in the
@@ -104,6 +99,13 @@ func (r *Route) HopFee(hopIndex int) lnwire.MilliSatoshi {
 	return incomingAmt - r.Hops[hopIndex].AmtToForward
 }
 
+// TotalFees is the sum of the fees paid at each hop within the final route. In
+// the case of a one-hop payment, this value will be zero as we don't need to
+// pay a fee to ourself.
+func (r *Route) TotalFees() lnwire.MilliSatoshi {
+	return r.TotalAmount - r.Hops[len(r.Hops)-1].AmtToForward
+}
+
 // NewRouteFromHops creates a new Route structure from the minimally required
 // information to perform the payment. It infers fee amounts and populates the
 // node, chan and prev/next hop maps.
@@ -124,7 +126,6 @@ func NewRouteFromHops(amtToSend lnwire.MilliSatoshi, timeLock uint32,
 		Hops:          hops,
 		TotalTimeLock: timeLock,
 		TotalAmount:   amtToSend,
-		TotalFees:     amtToSend - hops[len(hops)-1].AmtToForward,
 	}
 
 	return route, nil

routing/router_test.go

@@ -199,7 +199,7 @@ func TestFindRoutesWithFeeLimit(t *testing.T) {
 		t.Fatalf("unable to find any routes: %v", err)
 	}
 
-	if route.TotalFees > restrictions.FeeLimit {
+	if route.TotalFees() > restrictions.FeeLimit {
 		t.Fatalf("route exceeded fee limit: %v", spew.Sdump(route))
 	}
 

rpcserver.go

@@ -2753,7 +2753,7 @@ func (r *rpcServer) savePayment(route *route.Route,
 			CreationDate: time.Now(),
 		},
 		Path:           paymentPath,
-		Fee:            route.TotalFees,
+		Fee:            route.TotalFees(),
 		TimeLockLength: route.TotalTimeLock,
 	}
 	copy(payment.PaymentPreimage[:], preImage)
@@ -3123,7 +3123,7 @@ func (r *rpcServer) dispatchPaymentIntent(
 	}
 
 	// Calculate amount paid to receiver.
-	amt := route.TotalAmount - route.TotalFees
+	amt := route.TotalAmount - route.TotalFees()
 
 	// Save the completed payment to the database for record keeping
 	// purposes.