routerrpc: update final cltv delta default

The default was increased for the main sendpayment RPC in commit
d3fa9767a9729756bab9b4a1121344b265410b1a. This commit sets the
same default for QueryRoutes, routerrpc.SendPayment and
router.EstimateRouteFee.

lnrpc/routerrpc/router_backend.go

@@ -46,7 +46,7 @@ type RouterBackend struct {
 		amt lnwire.MilliSatoshi, restrictions *routing.RestrictParams,
 		destCustomRecords record.CustomSet,
 		routeHints map[route.Vertex][]*channeldb.ChannelEdgePolicy,
-		finalExpiry ...uint16) (*route.Route, error)
+		finalExpiry uint16) (*route.Route, error)
 
 	MissionControl MissionControl
 
@@ -63,6 +63,10 @@ type RouterBackend struct {
 	// MaxTotalTimelock is the maximum total time lock a route is allowed to
 	// have.
 	MaxTotalTimelock uint32
+
+	// DefaultFinalCltvDelta is the default value used as final cltv delta
+	// when an RPC caller doesn't specify a value.
+	DefaultFinalCltvDelta uint16
 }
 
 // MissionControl defines the mission control dependencies of routerrpc.
@@ -194,7 +198,7 @@ func (r *RouterBackend) QueryRoutes(ctx context.Context,
 	// We need to subtract the final delta before passing it into path
 	// finding. The optimal path is independent of the final cltv delta and
 	// the path finding algorithm is unaware of this value.
-	finalCLTVDelta := uint16(zpay32.DefaultFinalCLTVDelta)
+	finalCLTVDelta := r.DefaultFinalCltvDelta
 	if in.FinalCltvDelta != 0 {
 		finalCLTVDelta = uint16(in.FinalCltvDelta)
 	}
@@ -657,7 +661,7 @@ func (r *RouterBackend) extractIntentFromSendRequest(
 			payIntent.FinalCLTVDelta =
 				uint16(rpcPayReq.FinalCltvDelta)
 		} else {
-			payIntent.FinalCLTVDelta = zpay32.DefaultFinalCLTVDelta
+			payIntent.FinalCLTVDelta = r.DefaultFinalCltvDelta
 		}
 
 		// Amount.

lnrpc/routerrpc/router_backend_test.go

@@ -121,7 +121,7 @@ func testQueryRoutes(t *testing.T, useMissionControl bool, useMsat bool) {
 		amt lnwire.MilliSatoshi, restrictions *routing.RestrictParams,
 		_ record.CustomSet,
 		routeHints map[route.Vertex][]*channeldb.ChannelEdgePolicy,
-		finalExpiry ...uint16) (*route.Route, error) {
+		finalExpiry uint16) (*route.Route, error) {
 
 		if int64(amt) != amtSat*1000 {
 			t.Fatal("unexpected amount")

lnrpc/routerrpc/router_server.go

@@ -260,7 +260,7 @@ func (s *Server) EstimateRouteFee(ctx context.Context,
 		&routing.RestrictParams{
 			FeeLimit:  feeLimit,
 			CltvLimit: s.cfg.RouterBackend.MaxTotalTimelock,
-		}, nil, nil,
+		}, nil, nil, s.cfg.RouterBackend.DefaultFinalCltvDelta,
 	)
 	if err != nil {
 		return nil, err

routing/pathfind_test.go

@@ -2110,6 +2110,7 @@ func TestPathFindSpecExample(t *testing.T) {
 	const amt lnwire.MilliSatoshi = 4999999
 	route, err := ctx.router.FindRoute(
 		bobNode.PubKeyBytes, carol, amt, noRestrictions, nil, nil,
+		zpay32.DefaultFinalCLTVDelta,
 	)
 	if err != nil {
 		t.Fatalf("unable to find route: %v", err)
@@ -2165,6 +2166,7 @@ func TestPathFindSpecExample(t *testing.T) {
 	// We'll now request a route from A -> B -> C.
 	route, err = ctx.router.FindRoute(
 		source.PubKeyBytes, carol, amt, noRestrictions, nil, nil,
+		zpay32.DefaultFinalCLTVDelta,
 	)
 	if err != nil {
 		t.Fatalf("unable to find routes: %v", err)

routing/router.go

@@ -1403,14 +1403,7 @@ func (r *ChannelRouter) FindRoute(source, target route.Vertex,
 	amt lnwire.MilliSatoshi, restrictions *RestrictParams,
 	destCustomRecords record.CustomSet,
 	routeHints map[route.Vertex][]*channeldb.ChannelEdgePolicy,
-	finalExpiry ...uint16) (*route.Route, error) {
-
-	var finalCLTVDelta uint16
-	if len(finalExpiry) == 0 {
-		finalCLTVDelta = zpay32.DefaultFinalCLTVDelta
-	} else {
-		finalCLTVDelta = finalExpiry[0]
-	}
+	finalExpiry uint16) (*route.Route, error) {
 
 	log.Debugf("Searching for path to %v, sending %v", target, amt)
 
@@ -1441,7 +1434,7 @@ func (r *ChannelRouter) FindRoute(source, target route.Vertex,
 
 	// Now that we know the destination is reachable within the graph, we'll
 	// execute our path finding algorithm.
-	finalHtlcExpiry := currentHeight + int32(finalCLTVDelta)
+	finalHtlcExpiry := currentHeight + int32(finalExpiry)
 
 	path, err := findPath(
 		&graphParams{
@@ -1461,7 +1454,7 @@ func (r *ChannelRouter) FindRoute(source, target route.Vertex,
 		source, path, uint32(currentHeight),
 		finalHopParams{
 			amt:       amt,
-			cltvDelta: finalCLTVDelta,
+			cltvDelta: finalExpiry,
 			records:   destCustomRecords,
 		},
 	)

rpcserver.go

@@ -567,6 +567,7 @@ func newRPCServer(s *server, macService *macaroons.Service,
 		ActiveNetParams:       activeNetParams.Params,
 		Tower:                 s.controlTower,
 		MaxTotalTimelock:      cfg.MaxOutgoingCltvExpiry,
+		DefaultFinalCltvDelta: uint16(cfg.Bitcoin.TimeLockDelta),
 	}
 
 	genInvoiceFeatures := func() *lnwire.FeatureVector {