multi: adding no_padding flag to queryroutes lncli, rpc calls

This commit adds a no_padding option to queryroutes lncli and rpc
calls. This allows a caller to force lnd to omit any block padding
that would otherwise be added as a safety measure.

cmd/lncli/commands.go

@@ -3001,6 +3001,10 @@ var queryRoutesCommand = cli.Command{
 			Name:  "use_mc",
 			Usage: "use mission control probabilities",
 		},
+		cli.BoolFlag{
+			Name:  "no_padding",
+			Usage: "if true, omit block padding in the returned route",
+		},
 	},
 	Action: actionDecorator(queryRoutes),
 }
@@ -3051,6 +3055,7 @@ func queryRoutes(ctx *cli.Context) error {
 		FeeLimit:          feeLimit,
 		FinalCltvDelta:    int32(ctx.Int("final_cltv_delta")),
 		UseMissionControl: ctx.Bool("use_mc"),
+		NoPadding:         ctx.Bool("no_padding"),
 	}
 
 	route, err := client.QueryRoutes(ctxb, req)

lnrpc/routerrpc/router_backend.go

@@ -40,7 +40,7 @@ type RouterBackend struct {
 	// routes.
 	FindRoute func(source, target route.Vertex,
 		amt lnwire.MilliSatoshi, restrictions *routing.RestrictParams,
-		finalExpiry ...uint16) (*route.Route, error)
+		noPadding bool, finalExpiry ...uint16) (*route.Route, error)
 
 	MissionControl MissionControl
 
@@ -177,6 +177,8 @@ func (r *RouterBackend) QueryRoutes(ctx context.Context,
 		},
 	}
 
+	noPadding := in.NoPadding
+
 	// Query the channel router for a possible path to the destination that
 	// can carry `in.Amt` satoshis _including_ the total fee required on
 	// the route.
@@ -187,11 +189,11 @@ func (r *RouterBackend) QueryRoutes(ctx context.Context,
 
 	if in.FinalCltvDelta == 0 {
 		route, findErr = r.FindRoute(
-			sourcePubKey, targetPubKey, amtMSat, restrictions,
+			sourcePubKey, targetPubKey, amtMSat, restrictions, noPadding,
 		)
 	} else {
 		route, findErr = r.FindRoute(
-			sourcePubKey, targetPubKey, amtMSat, restrictions,
+			sourcePubKey, targetPubKey, amtMSat, restrictions, noPadding,
 			uint16(in.FinalCltvDelta),
 		)
 	}

lnrpc/routerrpc/router_backend_test.go

@@ -74,7 +74,7 @@ func testQueryRoutes(t *testing.T, useMissionControl bool) {
 
 	findRoute := func(source, target route.Vertex,
 		amt lnwire.MilliSatoshi, restrictions *routing.RestrictParams,
-		finalExpiry ...uint16) (*route.Route, error) {
+		noPadding bool, finalExpiry ...uint16) (*route.Route, error) {
 
 		if int64(amt) != request.Amt*1000 {
 			t.Fatal("unexpected amount")

lnrpc/routerrpc/router_server.go

@@ -243,13 +243,16 @@ func (s *Server) EstimateRouteFee(ctx context.Context,
 	// TODO: Change this into behaviour that makes more sense.
 	feeLimit := lnwire.NewMSatFromSatoshis(btcutil.SatoshiPerBitcoin)
 
+	// Add block padding
+	noPadding := false
+
 	// Finally, we'll query for a route to the destination that can carry
 	// that target amount, we'll only request a single route.
 	route, err := s.cfg.Router.FindRoute(
 		s.cfg.RouterBackend.SelfNode, destNode, amtMsat,
 		&routing.RestrictParams{
 			FeeLimit: feeLimit,
-		},
+		}, noPadding,
 	)
 	if err != nil {
 		return nil, err

lnrpc/rpc.proto

@@ -1657,6 +1657,12 @@ message QueryRoutesRequest {
     the optimal route.
     */
     bool use_mission_control = 9;
+
+    /**
+    If no_padding = true, then no block padding will be added to the returned
+    route.
+    */
+    bool no_padding = 10;
 }
 
 message EdgeLocator {

lnrpc/rpc.swagger.json

@@ -730,6 +730,14 @@
             "required": false,
             "type": "boolean",
             "format": "boolean"
+          },
+          {
+            "name": "no_padding",
+            "description": "*\nIf no_padding = true, then no block padding will be added to the returned\nroute.",
+            "in": "query",
+            "required": false,
+            "type": "boolean",
+            "format": "boolean"
           }
         ],
         "tags": [

routing/pathfind_test.go

@@ -1685,7 +1685,7 @@ func TestPathFindSpecExample(t *testing.T) {
 	carol := ctx.aliases["C"]
 	const amt lnwire.MilliSatoshi = 4999999
 	route, err := ctx.router.FindRoute(
-		bobNode.PubKeyBytes, carol, amt, noRestrictions,
+		bobNode.PubKeyBytes, carol, amt, noRestrictions, noPadding,
 	)
 	if err != nil {
 		t.Fatalf("unable to find route: %v", err)
@@ -1744,7 +1744,7 @@ 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,
+		source.PubKeyBytes, carol, amt, noRestrictions, noPadding,
 	)
 	if err != nil {
 		t.Fatalf("unable to find routes: %v", err)

routing/router.go

@@ -1437,7 +1437,7 @@ type routingMsg struct {
 // particular target destination to which it is able to send `amt` after
 // factoring in channel capacities and cumulative fees along the route.
 func (r *ChannelRouter) FindRoute(source, target route.Vertex,
-	amt lnwire.MilliSatoshi, restrictions *RestrictParams,
+	amt lnwire.MilliSatoshi, restrictions *RestrictParams, noPadding bool,
 	finalExpiry ...uint16) (*route.Route, error) {
 
 	var finalCLTVDelta uint16
@@ -1448,8 +1448,11 @@ func (r *ChannelRouter) FindRoute(source, target route.Vertex,
 	}
 
 	// Add BlockPadding to the finalCltvDelta so that the receiving node
-	// does not reject the HTLC if a block is mined while its in-flight.
-	finalCLTVDelta += BlockPadding
+	// does not reject the HTLC if a block is mined while its in-flight. If the
+	// noPadding option is set in the call, then don't add padding.
+	if !noPadding {
+		finalCLTVDelta += BlockPadding
+	}
 
 	log.Debugf("Searching for path to %x, sending %v", target, amt)
 

routing/router_test.go

@@ -227,10 +227,11 @@ func TestFindRoutesWithFeeLimit(t *testing.T) {
 		FeeLimit:          lnwire.NewMSatFromSatoshis(10),
 		ProbabilitySource: noProbabilitySource,
 	}
+	noPadding := false
 
 	route, err := ctx.router.FindRoute(
 		ctx.router.selfNode.PubKeyBytes,
-		target, paymentAmt, restrictions,
+		target, paymentAmt, restrictions, noPadding,
 		zpay32.DefaultFinalCLTVDelta,
 	)
 	if err != nil {
@@ -1076,6 +1077,8 @@ func TestIgnoreChannelEdgePolicyForUnknownChannel(t *testing.T) {
 func TestAddEdgeUnknownVertexes(t *testing.T) {
 	t.Parallel()
 
+	const noPadding = false
+
 	const startingBlockHeight = 101
 	ctx, cleanUp, err := createTestCtxFromFile(startingBlockHeight,
 		basicGraphFilePath)
@@ -1269,7 +1272,7 @@ func TestAddEdgeUnknownVertexes(t *testing.T) {
 	copy(targetPubKeyBytes[:], targetNode.SerializeCompressed())
 	_, err = ctx.router.FindRoute(
 		ctx.router.selfNode.PubKeyBytes,
-		targetPubKeyBytes, paymentAmt, noRestrictions,
+		targetPubKeyBytes, paymentAmt, noRestrictions, noPadding,
 		zpay32.DefaultFinalCLTVDelta,
 	)
 	if err != nil {
@@ -1312,7 +1315,7 @@ func TestAddEdgeUnknownVertexes(t *testing.T) {
 	// updated.
 	_, err = ctx.router.FindRoute(
 		ctx.router.selfNode.PubKeyBytes,
-		targetPubKeyBytes, paymentAmt, noRestrictions,
+		targetPubKeyBytes, paymentAmt, noRestrictions, noPadding,
 		zpay32.DefaultFinalCLTVDelta,
 	)
 	if err != nil {