routing: extend path finding to be TLV-EOB aware, allow dest TLV records

In this commit, we extend the path finding to be able to recognize when
a node needs the new TLV format, or the legacy format based on the
feature bits they expose. We also extend the `LightningPayment` struct
to allow the caller to specify an arbitrary set of TLV records which can
be used for a number of use-cases including various variants of
spontaneous payments.

routing/control_tower_test.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/btcec"
+	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/routing/route"
 
@@ -26,6 +27,7 @@ var (
 		ChannelID:        12345,
 		OutgoingTimeLock: 111,
 		AmtToForward:     555,
+		LegacyPayload:    true,
 	}
 
 	testRoute = route.Route{
@@ -144,7 +146,9 @@ func TestControlTowerSubscribeSuccess(t *testing.T) {
 		}
 
 		if !reflect.DeepEqual(result.Route, &attempt.Route) {
-			t.Fatal("unexpected route")
+			t.Fatalf("unexpected route: %v vs %v",
+				spew.Sdump(result.Route),
+				spew.Sdump(attempt.Route))
 		}
 
 		// After the final event, we expect the channel to be closed.

routing/missioncontrol_store_test.go

@@ -7,6 +7,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/lnwire"
 
 	"github.com/coreos/bbolt"
@@ -50,7 +51,8 @@ func TestMissionControlStore(t *testing.T) {
 		SourcePubKey: route.Vertex{1},
 		Hops: []*route.Hop{
 			{
-				PubKeyBytes: route.Vertex{2},
+				PubKeyBytes:   route.Vertex{2},
+				LegacyPayload: true,
 			},
 		},
 	}
@@ -99,10 +101,12 @@ func TestMissionControlStore(t *testing.T) {
 
 	// Check that results are stored in chronological order.
 	if !reflect.DeepEqual(&result1, results[0]) {
-		t.Fatal()
+		t.Fatalf("the results differ: %v vs %v", spew.Sdump(&result1),
+			spew.Sdump(results[0]))
 	}
 	if !reflect.DeepEqual(&result2, results[1]) {
-		t.Fatal()
+		t.Fatalf("the results differ: %v vs %v", spew.Sdump(&result2),
+			spew.Sdump(results[1]))
 	}
 
 	// Recreate store to test pruning.
@@ -132,9 +136,11 @@ func TestMissionControlStore(t *testing.T) {
 	}
 
 	if !reflect.DeepEqual(&result2, results[0]) {
-		t.Fatal()
+		t.Fatalf("the results differ: %v vs %v", spew.Sdump(&result2),
+			spew.Sdump(results[0]))
 	}
 	if !reflect.DeepEqual(&result3, results[1]) {
-		t.Fatal()
+		t.Fatalf("the results differ: %v vs %v", spew.Sdump(&result3),
+			spew.Sdump(results[1]))
 	}
 }

routing/missioncontrol_test.go

@@ -16,13 +16,15 @@ var (
 		SourcePubKey: route.Vertex{10},
 		Hops: []*route.Hop{
 			{
-				ChannelID:    1,
+				ChannelID:     1,
-				PubKeyBytes:  route.Vertex{11},
+				PubKeyBytes:   route.Vertex{11},
-				AmtToForward: 1000,
+				AmtToForward:  1000,
+				LegacyPayload: true,
 			},
 			{
-				ChannelID:   2,
+				ChannelID:     2,
-				PubKeyBytes: route.Vertex{12},
+				PubKeyBytes:   route.Vertex{12},
+				LegacyPayload: true,
 			},
 		},
 	}
@@ -167,7 +169,8 @@ func TestMissionControl(t *testing.T) {
 	// Check whether history snapshot looks sane.
 	history := ctx.mc.GetHistorySnapshot()
 	if len(history.Nodes) != 1 {
-		t.Fatal("unexpected number of nodes")
+		t.Fatalf("unexpected number of nodes: expected 1 got %v",
+			len(history.Nodes))
 	}
 
 	if len(history.Pairs) != 1 {

routing/pathfind.go

@@ -2,6 +2,7 @@ package routing
 
 import (
 	"container/heap"
+	"fmt"
 	"math"
 
 	"github.com/coreos/bbolt"
@@ -9,6 +10,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/routing/route"
+	"github.com/lightningnetwork/lnd/tlv"
 )
 
 const (
@@ -98,7 +100,8 @@ func isSamePath(path1, path2 []*channeldb.ChannelEdgePolicy) bool {
 // the source to the target node of the path finding attempt.
 func newRoute(amtToSend lnwire.MilliSatoshi, sourceVertex route.Vertex,
 	pathEdges []*channeldb.ChannelEdgePolicy, currentHeight uint32,
-	finalCLTVDelta uint16) (*route.Route, error) {
+	finalCLTVDelta uint16,
+	finalDestRecords []tlv.Record) (*route.Route, error) {
 
 	var (
 		hops []*route.Hop
@@ -179,7 +182,27 @@ func newRoute(amtToSend lnwire.MilliSatoshi, sourceVertex route.Vertex,
 			ChannelID:        edge.ChannelID,
 			AmtToForward:     amtToForward,
 			OutgoingTimeLock: outgoingTimeLock,
+			LegacyPayload:    true,
 		}
+
+		// We start out above by assuming that this node needs the
+		// legacy payload, as if we don't have the full
+		// NodeAnnouncement information for this node, then we can't
+		// assume it knows the latest features. If we do have a feature
+		// vector for this node, then we'll update the info now.
+		if edge.Node.Features != nil {
+			features := edge.Node.Features
+			currentHop.LegacyPayload = !features.HasFeature(
+				lnwire.TLVOnionPayloadOptional,
+			)
+		}
+
+		// If this is the last hop, then we'll populate any TLV records
+		// destined for it.
+		if i == len(pathEdges)-1 && len(finalDestRecords) != 0 {
+			currentHop.TLVRecords = finalDestRecords
+		}
+
 		hops = append([]*route.Hop{currentHop}, hops...)
 
 		// Finally, we update the amount that needs to flow into the
@@ -190,7 +213,8 @@ func newRoute(amtToSend lnwire.MilliSatoshi, sourceVertex route.Vertex,
 
 	// With the base routing data expressed as hops, build the full route
 	newRoute, err := route.NewRouteFromHops(
-		nextIncomingAmount, totalTimeLock, route.Vertex(sourceVertex), hops,
+		nextIncomingAmount, totalTimeLock, route.Vertex(sourceVertex),
+		hops,
 	)
 	if err != nil {
 		return nil, err
@@ -261,6 +285,11 @@ type RestrictParams struct {
 	// ctlv. After path finding is complete, the caller needs to increase
 	// all cltv expiry heights with the required final cltv delta.
 	CltvLimit *uint32
+
+	// DestPayloadTLV should be set to true if we need to drop off a TLV
+	// payload at the final hop in order to properly complete this payment
+	// attempt.
+	DestPayloadTLV bool
 }
 
 // PathFindingConfig defines global parameters that control the trade-off in
@@ -316,10 +345,34 @@ func findPath(g *graphParams, r *RestrictParams, cfg *PathFindingConfig,
 		node *channeldb.LightningNode) error {
 		// TODO(roasbeef): with larger graph can just use disk seeks
 		// with a visited map
-		distance[route.Vertex(node.PubKeyBytes)] = nodeWithDist{
+		vertex := route.Vertex(node.PubKeyBytes)
+		distance[vertex] = nodeWithDist{
 			dist: infinity,
 			node: route.Vertex(node.PubKeyBytes),
 		}
+
+		// If we don't have any features for this node, then we can
+		// stop here.
+		if node.Features == nil || !r.DestPayloadTLV {
+			return nil
+		}
+
+		// We only need to perform this check for the final node, so we
+		// can exit here if this isn't them.
+		if vertex != target {
+			return nil
+		}
+
+		// If we have any records for the final hop, then we'll check
+		// not to ensure that they are actually able to interpret them.
+		supportsTLV := node.Features.HasFeature(
+			lnwire.TLVOnionPayloadOptional,
+		)
+		if !supportsTLV {
+			return fmt.Errorf("destination hop doesn't " +
+				"understand new TLV paylods")
+		}
+
 		return nil
 	}); err != nil {
 		return nil, err

routing/pathfind_test.go

@@ -670,7 +670,8 @@ func TestFindLowestFeePath(t *testing.T) {
 	}
 	route, err := newRoute(
 		paymentAmt, sourceVertex, path, startingHeight,
-		finalHopCLTV)
+		finalHopCLTV, nil,
+	)
 	if err != nil {
 		t.Fatalf("unable to create path: %v", err)
 	}
@@ -819,7 +820,7 @@ func testBasicGraphPathFindingCase(t *testing.T, graphInstance *testGraphInstanc
 
 	route, err := newRoute(
 		paymentAmt, sourceVertex, path, startingHeight,
-		finalHopCLTV,
+		finalHopCLTV, nil,
 	)
 	if err != nil {
 		t.Fatalf("unable to create path: %v", err)
@@ -857,9 +858,15 @@ func testBasicGraphPathFindingCase(t *testing.T, graphInstance *testGraphInstanc
 	for i := 0; i < len(expectedHops)-1; i++ {
 		var expectedHop [8]byte
 		binary.BigEndian.PutUint64(expectedHop[:], route.Hops[i+1].ChannelID)
-		if !bytes.Equal(sphinxPath[i].HopData.NextAddress[:], expectedHop[:]) {
+
+		hopData, err := sphinxPath[i].HopPayload.HopData()
+		if err != nil {
+			t.Fatalf("unable to make hop data: %v", err)
+		}
+
+		if !bytes.Equal(hopData.NextAddress[:], expectedHop[:]) {
 			t.Fatalf("first hop has incorrect next hop: expected %x, got %x",
-				expectedHop[:], sphinxPath[i].HopData.NextAddress)
+				expectedHop[:], hopData.NextAddress[:])
 		}
 	}
 
@@ -867,9 +874,15 @@ func testBasicGraphPathFindingCase(t *testing.T, graphInstance *testGraphInstanc
 	// to indicate it's the exit hop.
 	var exitHop [8]byte
 	lastHopIndex := len(expectedHops) - 1
-	if !bytes.Equal(sphinxPath[lastHopIndex].HopData.NextAddress[:], exitHop[:]) {
+
+	hopData, err := sphinxPath[lastHopIndex].HopPayload.HopData()
+	if err != nil {
+		t.Fatalf("unable to create hop data: %v", err)
+	}
+
+	if !bytes.Equal(hopData.NextAddress[:], exitHop[:]) {
 		t.Fatalf("first hop has incorrect next hop: expected %x, got %x",
-			exitHop[:], sphinxPath[lastHopIndex].HopData.NextAddress)
+			exitHop[:], hopData.NextAddress)
 	}
 
 	var expectedTotalFee lnwire.MilliSatoshi
@@ -1001,7 +1014,11 @@ func TestNewRoute(t *testing.T) {
 		timeLockDelta uint16) *channeldb.ChannelEdgePolicy {
 
 		return &channeldb.ChannelEdgePolicy{
-			Node:                      &channeldb.LightningNode{},
+			Node: &channeldb.LightningNode{
+				Features: lnwire.NewFeatureVector(
+					nil, nil,
+				),
+			},
 			FeeProportionalMillionths: feeRate,
 			FeeBaseMSat:               baseFee,
 			TimeLockDelta:             timeLockDelta,
@@ -1176,9 +1193,11 @@ func TestNewRoute(t *testing.T) {
 		}
 
 		t.Run(testCase.name, func(t *testing.T) {
-			route, err := newRoute(testCase.paymentAmount,
+			route, err := newRoute(
-				sourceVertex, testCase.hops, startingHeight,
+				testCase.paymentAmount, sourceVertex,
-				finalHopCLTV)
+				testCase.hops, startingHeight, finalHopCLTV,
+				nil,
+			)
 
 			if testCase.expectError {
 				expectedCode := testCase.expectedErrorCode
@@ -1683,7 +1702,7 @@ 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, nil,
 	)
 	if err != nil {
 		t.Fatalf("unable to find route: %v", err)
@@ -1742,7 +1761,7 @@ 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, nil,
 	)
 	if err != nil {
 		t.Fatalf("unable to find routes: %v", err)
@@ -1925,7 +1944,7 @@ func TestRestrictOutgoingChannel(t *testing.T) {
 	}
 	route, err := newRoute(
 		paymentAmt, sourceVertex, path, startingHeight,
-		finalHopCLTV,
+		finalHopCLTV, nil,
 	)
 	if err != nil {
 		t.Fatalf("unable to create path: %v", err)
@@ -2033,6 +2052,7 @@ func testCltvLimit(t *testing.T, limit uint32, expectedChannel uint64) {
 	)
 	route, err := newRoute(
 		paymentAmt, sourceVertex, path, startingHeight, finalHopCLTV,
+		nil,
 	)
 	if err != nil {
 		t.Fatalf("unable to create path: %v", err)

routing/payment_session.go

@@ -127,6 +127,7 @@ func (p *paymentSession) RequestRoute(payment *LightningPayment,
 	sourceVertex := route.Vertex(ss.SelfNode.PubKeyBytes)
 	route, err := newRoute(
 		payment.Amount, sourceVertex, path, height, finalCltvDelta,
+		payment.FinalDestRecords,
 	)
 	if err != nil {
 		// TODO(roasbeef): return which edge/vertex didn't work

routing/payment_session_test.go

@@ -26,7 +26,11 @@ func TestRequestRoute(t *testing.T) {
 
 		path := []*channeldb.ChannelEdgePolicy{
 			{
-				Node: &channeldb.LightningNode{},
+				Node: &channeldb.LightningNode{
+					Features: lnwire.NewFeatureVector(
+						nil, nil,
+					),
+				},
 			},
 		}
 

routing/router.go

@@ -26,6 +26,7 @@ import (
 	"github.com/lightningnetwork/lnd/routing/chainview"
 	"github.com/lightningnetwork/lnd/routing/route"
 	"github.com/lightningnetwork/lnd/ticker"
+	"github.com/lightningnetwork/lnd/tlv"
 	"github.com/lightningnetwork/lnd/zpay32"
 )
 
@@ -1429,6 +1430,7 @@ type routingMsg struct {
 // factoring in channel capacities and cumulative fees along the route.
 func (r *ChannelRouter) FindRoute(source, target route.Vertex,
 	amt lnwire.MilliSatoshi, restrictions *RestrictParams,
+	destTlvRecords []tlv.Record,
 	finalExpiry ...uint16) (*route.Route, error) {
 
 	var finalCLTVDelta uint16
@@ -1482,6 +1484,7 @@ func (r *ChannelRouter) FindRoute(source, target route.Vertex,
 	// Create the route with absolute time lock values.
 	route, err := newRoute(
 		amt, source, path, uint32(currentHeight), finalCLTVDelta,
+		destTlvRecords,
 	)
 	if err != nil {
 		return nil, err
@@ -1630,7 +1633,11 @@ type LightningPayment struct {
 	// attempting to complete.
 	PaymentRequest []byte
 
-	// TODO(roasbeef): add e2e message?
+	// FinalDestRecords are TLV records that are to be sent to the final
+	// hop in the new onion payload format. If the destination does not
+	// understand this new onion payload format, then the payment will
+	// fail.
+	FinalDestRecords []tlv.Record
 }
 
 // SendPayment attempts to send a payment as described within the passed
@@ -1694,6 +1701,8 @@ func (r *ChannelRouter) preparePayment(payment *LightningPayment) (
 
 	// Record this payment hash with the ControlTower, ensuring it is not
 	// already in-flight.
+	//
+	// TODO(roasbeef): store records as part of creation info?
 	info := &channeldb.PaymentCreationInfo{
 		PaymentHash:    payment.PaymentHash,
 		Value:          payment.Amount,

routing/router_test.go

@@ -231,7 +231,7 @@ func TestFindRoutesWithFeeLimit(t *testing.T) {
 
 	route, err := ctx.router.FindRoute(
 		ctx.router.selfNode.PubKeyBytes,
-		target, paymentAmt, restrictions,
+		target, paymentAmt, restrictions, nil,
 		zpay32.DefaultFinalCLTVDelta,
 	)
 	if err != nil {
@@ -390,12 +390,14 @@ func TestChannelUpdateValidation(t *testing.T) {
 
 	hops := []*route.Hop{
 		{
-			ChannelID:   1,
+			ChannelID:     1,
-			PubKeyBytes: hop1,
+			PubKeyBytes:   hop1,
+			LegacyPayload: true,
 		},
 		{
-			ChannelID:   2,
+			ChannelID:     2,
-			PubKeyBytes: hop2,
+			PubKeyBytes:   hop2,
+			LegacyPayload: true,
 		},
 	}
 
@@ -1074,8 +1076,9 @@ func TestAddEdgeUnknownVertexes(t *testing.T) {
 	t.Parallel()
 
 	const startingBlockHeight = 101
-	ctx, cleanUp, err := createTestCtxFromFile(startingBlockHeight,
+	ctx, cleanUp, err := createTestCtxFromFile(
-		basicGraphFilePath)
+		startingBlockHeight, basicGraphFilePath,
+	)
 	if err != nil {
 		t.Fatalf("unable to create router: %v", err)
 	}
@@ -1108,7 +1111,8 @@ func TestAddEdgeUnknownVertexes(t *testing.T) {
 	fundingTx, _, chanID, err := createChannelEdge(ctx,
 		bitcoinKey1.SerializeCompressed(),
 		bitcoinKey2.SerializeCompressed(),
-		10000, 500)
+		10000, 500,
+	)
 	if err != nil {
 		t.Fatalf("unable to create channel edge: %v", err)
 	}
@@ -1266,7 +1270,7 @@ func TestAddEdgeUnknownVertexes(t *testing.T) {
 	copy(targetPubKeyBytes[:], targetNode.SerializeCompressed())
 	_, err = ctx.router.FindRoute(
 		ctx.router.selfNode.PubKeyBytes,
-		targetPubKeyBytes, paymentAmt, noRestrictions,
+		targetPubKeyBytes, paymentAmt, noRestrictions, nil,
 		zpay32.DefaultFinalCLTVDelta,
 	)
 	if err != nil {
@@ -1309,7 +1313,7 @@ func TestAddEdgeUnknownVertexes(t *testing.T) {
 	// updated.
 	_, err = ctx.router.FindRoute(
 		ctx.router.selfNode.PubKeyBytes,
-		targetPubKeyBytes, paymentAmt, noRestrictions,
+		targetPubKeyBytes, paymentAmt, noRestrictions, nil,
 		zpay32.DefaultFinalCLTVDelta,
 	)
 	if err != nil {
@@ -2632,12 +2636,14 @@ func TestRouterPaymentStateMachine(t *testing.T) {
 	hop2 := testGraph.aliasMap["c"]
 	hops := []*route.Hop{
 		{
-			ChannelID:   1,
+			ChannelID:     1,
-			PubKeyBytes: hop1,
+			PubKeyBytes:   hop1,
+			LegacyPayload: true,
 		},
 		{
-			ChannelID:   2,
+			ChannelID:     2,
-			PubKeyBytes: hop2,
+			PubKeyBytes:   hop2,
+			LegacyPayload: true,
 		},
 	}
 
@@ -3270,14 +3276,16 @@ func TestSendToRouteStructuredError(t *testing.T) {
 	hop2 := ctx.aliases["c"]
 	hops := []*route.Hop{
 		{
-			ChannelID:    1,
+			ChannelID:     1,
-			PubKeyBytes:  hop1,
+			PubKeyBytes:   hop1,
-			AmtToForward: payAmt,
+			AmtToForward:  payAmt,
+			LegacyPayload: true,
 		},
 		{
-			ChannelID:    2,
+			ChannelID:     2,
-			PubKeyBytes:  hop2,
+			PubKeyBytes:   hop2,
-			AmtToForward: payAmt,
+			AmtToForward:  payAmt,
+			LegacyPayload: true,
 		},
 	}