Merge pull request #5206 from carlaKC/4987-heightexpirywatcher

invoices: add height based expiry watcher

config.go

@@ -347,6 +347,8 @@ type Config struct {
 
 	GcCanceledInvoicesOnTheFly bool `long:"gc-canceled-invoices-on-the-fly" description:"If true, we'll delete newly canceled invoices on the fly."`
 
+	Invoices *lncfg.Invoices `group:"invoices" namespace:"invoices"`
+
 	Routing *lncfg.Routing `group:"routing" namespace:"routing"`
 
 	Gossip *lncfg.Gossip `group:"gossip" namespace:"gossip"`
@@ -532,6 +534,9 @@ func DefaultConfig() Config {
 			MaxChannelUpdateBurst: discovery.DefaultMaxChannelUpdateBurst,
 			ChannelUpdateInterval: discovery.DefaultChannelUpdateInterval,
 		},
+		Invoices: &lncfg.Invoices{
+			HoldExpiryDelta: lncfg.DefaultHoldInvoiceExpiryDelta,
+		},
 		MaxOutgoingCltvExpiry:   htlcswitch.DefaultMaxOutgoingCltvExpiry,
 		MaxChannelFeeAllocation: htlcswitch.DefaultMaxLinkFeeAllocation,
 		MaxCommitFeeRateAnchors: lnwallet.DefaultAnchorsCommitMaxFeeRateSatPerVByte,
@@ -1389,6 +1394,18 @@ func ValidateConfig(cfg Config, usageMessage string,
 		return nil, err
 	}
 
+	// Log a warning if our expiry delta is not greater than our incoming
+	// broadcast delta. We do not fail here because this value may be set
+	// to zero to intentionally keep lnd's behavior unchanged from when we
+	// didn't auto-cancel these invoices.
+	if cfg.Invoices.HoldExpiryDelta <= lncfg.DefaultIncomingBroadcastDelta {
+		ltndLog.Warnf("Invoice hold expiry delta: %v <= incoming "+
+			"delta: %v, accepted hold invoices will force close "+
+			"channels if they are not canceled manually",
+			cfg.Invoices.HoldExpiryDelta,
+			lncfg.DefaultIncomingBroadcastDelta)
+	}
+
 	// Validate the subconfigs for workers, caches, and the tower client.
 	err = lncfg.Validate(
 		cfg.Workers,

htlcswitch/mock.go

@@ -797,6 +797,20 @@ type mockInvoiceRegistry struct {
 	cleanup func()
 }
 
+type mockChainNotifier struct {
+	chainntnfs.ChainNotifier
+}
+
+// RegisterBlockEpochNtfn mocks a successful call to register block
+// notifications.
+func (m *mockChainNotifier) RegisterBlockEpochNtfn(*chainntnfs.BlockEpoch) (
+	*chainntnfs.BlockEpochEvent, error) {
+
+	return &chainntnfs.BlockEpochEvent{
+		Cancel: func() {},
+	}, nil
+}
+
 func newMockRegistry(minDelta uint32) *mockInvoiceRegistry {
 	cdb, cleanup, err := newDB()
 	if err != nil {
@@ -805,7 +819,10 @@ func newMockRegistry(minDelta uint32) *mockInvoiceRegistry {
 
 	registry := invoices.NewRegistry(
 		cdb,
-		invoices.NewInvoiceExpiryWatcher(clock.NewDefaultClock()),
+		invoices.NewInvoiceExpiryWatcher(
+			clock.NewDefaultClock(), 0, 0, nil,
+			&mockChainNotifier{},
+		),
 		&invoices.RegistryConfig{
 			FinalCltvRejectDelta: 5,
 		},

invoices/invoice_expiry_watcher.go

@@ -5,6 +5,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/lntypes"
@@ -34,6 +36,28 @@ func (e invoiceExpiryTs) Less(other queue.PriorityQueueItem) bool {
 	return e.Expiry.Before(other.(*invoiceExpiryTs).Expiry)
 }
 
+// Compile time assertion that invoiceExpiryHeight implements invoiceExpiry.
+var _ invoiceExpiry = (*invoiceExpiryHeight)(nil)
+
+// invoiceExpiryHeight holds information about an invoice which can be used to
+// cancel it based on its expiry height.
+type invoiceExpiryHeight struct {
+	paymentHash  lntypes.Hash
+	expiryHeight uint32
+}
+
+// Less implements PriorityQueueItem.Less such that the top item in the
+// priority queue is the lowest block height.
+func (b invoiceExpiryHeight) Less(other queue.PriorityQueueItem) bool {
+	return b.expiryHeight < other.(*invoiceExpiryHeight).expiryHeight
+}
+
+// expired returns a boolean that indicates whether this entry has expired,
+// taking our expiry delta into account.
+func (b invoiceExpiryHeight) expired(currentHeight, delta uint32) bool {
+	return currentHeight+delta >= b.expiryHeight
+}
+
 // InvoiceExpiryWatcher handles automatic invoice cancellation of expried
 // invoices. Upon start InvoiceExpiryWatcher will retrieve all pending (not yet
 // settled or canceled) invoices invoices to its watcing queue. When a new
@@ -49,6 +73,21 @@ type InvoiceExpiryWatcher struct {
 	// It is useful for testing.
 	clock clock.Clock
 
+	// notifier provides us with block height updates.
+	notifier chainntnfs.ChainNotifier
+
+	// blockExpiryDelta is the number of blocks before a htlc's expiry that
+	// we expire the invoice based on expiry height. We use a delta because
+	// we will go to some delta before our expiry, so we want to cancel
+	// before this to prevent force closes.
+	blockExpiryDelta uint32
+
+	// currentHeight is the current block height.
+	currentHeight uint32
+
+	// currentHash is the block hash for our current height.
+	currentHash *chainhash.Hash
+
 	// cancelInvoice is a template method that cancels an expired invoice.
 	cancelInvoice func(lntypes.Hash, bool) error
 
@@ -56,6 +95,15 @@ type InvoiceExpiryWatcher struct {
 	// the next invoice to expire.
 	timestampExpiryQueue queue.PriorityQueue
 
+	// blockExpiryQueue holds blockExpiry items and is used to find the
+	// next invoice to expire based on block height. Only hold invoices
+	// with active htlcs are added to this queue, because they require
+	// manual cancellation when the hltc is going to time out. Items in
+	// this queue may already be in the timestampExpiryQueue, this is ok
+	// because they will not be expired based on timestamp if they have
+	// active htlcs.
+	blockExpiryQueue queue.PriorityQueue
+
 	// newInvoices channel is used to wake up the main loop when a new
 	// invoices is added.
 	newInvoices chan []invoiceExpiry
@@ -67,9 +115,16 @@ type InvoiceExpiryWatcher struct {
 }
 
 // NewInvoiceExpiryWatcher creates a new InvoiceExpiryWatcher instance.
-func NewInvoiceExpiryWatcher(clock clock.Clock) *InvoiceExpiryWatcher {
+func NewInvoiceExpiryWatcher(clock clock.Clock,
+	expiryDelta, startHeight uint32, startHash *chainhash.Hash,
+	notifier chainntnfs.ChainNotifier) *InvoiceExpiryWatcher {
+
 	return &InvoiceExpiryWatcher{
 		clock:            clock,
+		notifier:         notifier,
+		blockExpiryDelta: expiryDelta,
+		currentHeight:    startHeight,
+		currentHash:      startHash,
 		newInvoices:      make(chan []invoiceExpiry),
 		quit:             make(chan struct{}),
 	}
@@ -91,8 +146,17 @@ func (ew *InvoiceExpiryWatcher) Start(
 
 	ew.started = true
 	ew.cancelInvoice = cancelInvoice
+
+	ntfn, err := ew.notifier.RegisterBlockEpochNtfn(&chainntnfs.BlockEpoch{
+		Height: int32(ew.currentHeight),
+		Hash:   ew.currentHash,
+	})
+	if err != nil {
+		return err
+	}
+
 	ew.wg.Add(1)
-	go ew.mainLoop()
+	go ew.mainLoop(ntfn)
 
 	return nil
 }
@@ -122,6 +186,32 @@ func makeInvoiceExpiry(paymentHash lntypes.Hash,
 	case channeldb.ContractOpen:
 		return makeTimestampExpiry(paymentHash, invoice)
 
+	// If an invoice has active htlcs, we want to expire it based on block
+	// height. We only do this for hodl invoices, since regular invoices
+	// should resolve themselves automatically.
+	case channeldb.ContractAccepted:
+		if !invoice.HodlInvoice {
+			log.Debugf("Invoice in accepted state not added to "+
+				"expiry watcher: %v", paymentHash)
+
+			return nil
+		}
+
+		var minHeight uint32
+		for _, htlc := range invoice.Htlcs {
+			// We only care about accepted htlcs, since they will
+			// trigger force-closes.
+			if htlc.State != channeldb.HtlcStateAccepted {
+				continue
+			}
+
+			if minHeight == 0 || htlc.Expiry < minHeight {
+				minHeight = htlc.Expiry
+			}
+		}
+
+		return makeHeightExpiry(paymentHash, minHeight)
+
 	default:
 		log.Debugf("Invoice not added to expiry watcher: %v",
 			paymentHash)
@@ -151,9 +241,28 @@ func makeTimestampExpiry(paymentHash lntypes.Hash,
 	}
 }
 
+// makeHeightExpiry creates height-based expiry for an invoice based on its
+// lowest htlc expiry height.
+func makeHeightExpiry(paymentHash lntypes.Hash,
+	minHeight uint32) *invoiceExpiryHeight {
+
+	if minHeight == 0 {
+		log.Warnf("make height expiry called with 0 height")
+		return nil
+	}
+
+	return &invoiceExpiryHeight{
+		paymentHash:  paymentHash,
+		expiryHeight: minHeight,
+	}
+}
+
 // AddInvoices adds invoices to the InvoiceExpiryWatcher.
 func (ew *InvoiceExpiryWatcher) AddInvoices(invoices ...invoiceExpiry) {
-	if len(invoices) > 0 {
+	if len(invoices) == 0 {
+		return
+	}
+
 	select {
 	case ew.newInvoices <- invoices:
 		log.Debugf("Added %d invoices to the expiry watcher",
@@ -163,7 +272,6 @@ func (ew *InvoiceExpiryWatcher) AddInvoices(invoices ...invoiceExpiry) {
 	// of concurrent shutdown.
 	case <-ew.quit:
 	}
-	}
 }
 
 // nextTimestampExpiry returns a Time chan to wait on until the next invoice
@@ -178,6 +286,23 @@ func (ew *InvoiceExpiryWatcher) nextTimestampExpiry() <-chan time.Time {
 	return nil
 }
 
+// nextHeightExpiry returns a channel that will immediately be read from if
+// the top item on our queue has expired.
+func (ew *InvoiceExpiryWatcher) nextHeightExpiry() <-chan uint32 {
+	if ew.blockExpiryQueue.Empty() {
+		return nil
+	}
+
+	top := ew.blockExpiryQueue.Top().(*invoiceExpiryHeight)
+	if !top.expired(ew.currentHeight, ew.blockExpiryDelta) {
+		return nil
+	}
+
+	blockChan := make(chan uint32, 1)
+	blockChan <- top.expiryHeight
+	return blockChan
+}
+
 // cancelNextExpiredInvoice will cancel the next expired invoice and removes
 // it from the expiry queue.
 func (ew *InvoiceExpiryWatcher) cancelNextExpiredInvoice() {
@@ -198,6 +323,25 @@ func (ew *InvoiceExpiryWatcher) cancelNextExpiredInvoice() {
 	}
 }
 
+// cancelNextHeightExpiredInvoice looks at our height based queue and expires
+// the next invoice if we have reached its expiry block.
+func (ew *InvoiceExpiryWatcher) cancelNextHeightExpiredInvoice() {
+	if ew.blockExpiryQueue.Empty() {
+		return
+	}
+
+	top := ew.blockExpiryQueue.Top().(*invoiceExpiryHeight)
+	if !top.expired(ew.currentHeight, ew.blockExpiryDelta) {
+		return
+	}
+
+	// We always force-cancel block-based expiry so that we can
+	// cancel invoices that have been accepted but not yet resolved.
+	// This helps us avoid force closes.
+	ew.expireInvoice(top.paymentHash, true)
+	ew.blockExpiryQueue.Pop()
+}
+
 // expireInvoice attempts to expire an invoice and logs an error if we get an
 // unexpected error.
 func (ew *InvoiceExpiryWatcher) expireInvoice(hash lntypes.Hash, force bool) {
@@ -226,6 +370,11 @@ func (ew *InvoiceExpiryWatcher) pushInvoices(invoices []invoiceExpiry) {
 				ew.timestampExpiryQueue.Push(expiry)
 			}
 
+		case *invoiceExpiryHeight:
+			if expiry != nil {
+				ew.blockExpiryQueue.Push(expiry)
+			}
+
 		default:
 			log.Errorf("unexpected queue item: %T", inv)
 		}
@@ -234,12 +383,20 @@ func (ew *InvoiceExpiryWatcher) pushInvoices(invoices []invoiceExpiry) {
 
 // mainLoop is a goroutine that receives new invoices and handles cancellation
 // of expired invoices.
-func (ew *InvoiceExpiryWatcher) mainLoop() {
+func (ew *InvoiceExpiryWatcher) mainLoop(blockNtfns *chainntnfs.BlockEpochEvent) {
-	defer ew.wg.Done()
+	defer func() {
+		blockNtfns.Cancel()
+		ew.wg.Done()
+	}()
+
+	// We have two different queues, so we use a different cancel method
+	// depending on which expiry condition we have hit. Starting with time
+	// based expiry is an arbitrary choice to start off.
+	cancelNext := ew.cancelNextExpiredInvoice
 
 	for {
 		// Cancel any invoices that may have expired.
-		ew.cancelNextExpiredInvoice()
+		cancelNext()
 
 		select {
 
@@ -252,13 +409,29 @@ func (ew *InvoiceExpiryWatcher) mainLoop() {
 		default:
 			select {
 
-			case <-ew.nextTimestampExpiry():
 			// Wait until the next invoice expires.
+			case <-ew.nextTimestampExpiry():
+				cancelNext = ew.cancelNextExpiredInvoice
+				continue
+
+			case <-ew.nextHeightExpiry():
+				cancelNext = ew.cancelNextHeightExpiredInvoice
 				continue
 
 			case newInvoices := <-ew.newInvoices:
 				ew.pushInvoices(newInvoices)
 
+			// Consume new blocks.
+			case block, ok := <-blockNtfns.Epochs:
+				if !ok {
+					log.Debugf("block notifications " +
+						"canceled")
+					return
+				}
+
+				ew.currentHeight = uint32(block.Height)
+				ew.currentHash = block.Hash
+
 			case <-ew.quit:
 				return
 			}

invoices/invoice_expiry_watcher_test.go

@@ -5,6 +5,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/lightningnetwork/lnd/chainntnfs"
+	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/lntypes"
 )
@@ -19,13 +21,40 @@ type invoiceExpiryWatcherTest struct {
 	canceledInvoices []lntypes.Hash
 }
 
+type mockChainNotifier struct {
+	chainntnfs.ChainNotifier
+
+	blockChan chan *chainntnfs.BlockEpoch
+}
+
+func newMockNotifier() *mockChainNotifier {
+	return &mockChainNotifier{
+		blockChan: make(chan *chainntnfs.BlockEpoch),
+	}
+}
+
+// RegisterBlockEpochNtfn mocks a block epoch notification, using the mock's
+// block channel to deliver blocks to the client.
+func (m *mockChainNotifier) RegisterBlockEpochNtfn(*chainntnfs.BlockEpoch) (
+	*chainntnfs.BlockEpochEvent, error) {
+
+	return &chainntnfs.BlockEpochEvent{
+		Epochs: m.blockChan,
+		Cancel: func() {},
+	}, nil
+}
+
 // newInvoiceExpiryWatcherTest creates a new InvoiceExpiryWatcher test fixture
 // and sets up the test environment.
 func newInvoiceExpiryWatcherTest(t *testing.T, now time.Time,
 	numExpiredInvoices, numPendingInvoices int) *invoiceExpiryWatcherTest {
 
+	mockNotifier := newMockNotifier()
 	test := &invoiceExpiryWatcherTest{
-		watcher: NewInvoiceExpiryWatcher(clock.NewTestClock(testTime)),
+		watcher: NewInvoiceExpiryWatcher(
+			clock.NewTestClock(testTime), 0,
+			uint32(testCurrentHeight), nil, mockNotifier,
+		),
 		testData: generateInvoiceExpiryTestData(
 			t, now, 0, numExpiredInvoices, numPendingInvoices,
 		),
@@ -84,7 +113,10 @@ func (t *invoiceExpiryWatcherTest) checkExpectations() {
 
 // Tests that InvoiceExpiryWatcher can be started and stopped.
 func TestInvoiceExpiryWatcherStartStop(t *testing.T) {
-	watcher := NewInvoiceExpiryWatcher(clock.NewTestClock(testTime))
+	watcher := NewInvoiceExpiryWatcher(
+		clock.NewTestClock(testTime), 0, uint32(testCurrentHeight), nil,
+		newMockNotifier(),
+	)
 	cancel := func(lntypes.Hash, bool) error {
 		t.Fatalf("unexpected call")
 		return nil
@@ -172,3 +204,115 @@ func TestInvoiceExpiryWhenAddingMultipleInvoices(t *testing.T) {
 	test.watcher.Stop()
 	test.checkExpectations()
 }
+
+// TestExpiredHodlInv tests expiration of an already-expired hodl invoice
+// which has no htlcs.
+func TestExpiredHodlInv(t *testing.T) {
+	t.Parallel()
+
+	creationDate := testTime.Add(time.Hour * -24)
+	expiry := time.Hour
+
+	test := setupHodlExpiry(
+		t, creationDate, expiry, 0, channeldb.ContractOpen, nil,
+	)
+
+	test.assertCanceled(t, test.hash)
+	test.watcher.Stop()
+}
+
+// TestAcceptedHodlNotExpired tests that hodl invoices which are in an accepted
+// state are not expired once their time-based expiry elapses, using a regular
+// invoice that expires at the same time as a control to ensure that invoices
+// with that timestamp would otherwise be expired.
+func TestAcceptedHodlNotExpired(t *testing.T) {
+	t.Parallel()
+
+	creationDate := testTime
+	expiry := time.Hour
+
+	test := setupHodlExpiry(
+		t, creationDate, expiry, 0, channeldb.ContractAccepted, nil,
+	)
+	defer test.watcher.Stop()
+
+	// Add another invoice that will expire at our expiry time as a control
+	// value.
+	tsExpires := &invoiceExpiryTs{
+		PaymentHash: lntypes.Hash{1, 2, 3},
+		Expiry:      creationDate.Add(expiry),
+		Keysend:     true,
+	}
+	test.watcher.AddInvoices(tsExpires)
+
+	test.mockClock.SetTime(creationDate.Add(expiry + 1))
+
+	// Assert that only the ts expiry invoice is expired.
+	test.assertCanceled(t, tsExpires.PaymentHash)
+}
+
+// TestHeightAlreadyExpired tests the case where we add an invoice with htlcs
+// that have already expired to the expiry watcher.
+func TestHeightAlreadyExpired(t *testing.T) {
+	t.Parallel()
+
+	expiredHtlc := []*channeldb.InvoiceHTLC{
+		{
+			State:  channeldb.HtlcStateAccepted,
+			Expiry: uint32(testCurrentHeight),
+		},
+	}
+
+	test := setupHodlExpiry(
+		t, testTime, time.Hour, 0, channeldb.ContractAccepted,
+		expiredHtlc,
+	)
+	defer test.watcher.Stop()
+
+	test.assertCanceled(t, test.hash)
+}
+
+// TestExpiryHeightArrives tests the case where we add a hodl invoice to the
+// expiry watcher when it has no htlcs, htlcs are added and then they finally
+// expire. We use a non-zero delta for this test to check that we expire with
+// sufficient buffer.
+func TestExpiryHeightArrives(t *testing.T) {
+	var (
+		creationDate        = testTime
+		expiry              = time.Hour * 2
+		delta        uint32 = 1
+	)
+
+	// Start out with a hodl invoice that is open, and has no htlcs.
+	test := setupHodlExpiry(
+		t, creationDate, expiry, delta, channeldb.ContractOpen, nil,
+	)
+	defer test.watcher.Stop()
+
+	htlc1 := uint32(testCurrentHeight + 10)
+	expiry1 := makeHeightExpiry(test.hash, htlc1)
+
+	// Add htlcs to our invoice and progress its state to accepted.
+	test.watcher.AddInvoices(expiry1)
+	test.setState(channeldb.ContractAccepted)
+
+	// Progress time so that our expiry has elapsed. We no longer expect
+	// this invoice to be canceled because it has been accepted.
+	test.mockClock.SetTime(creationDate.Add(expiry))
+
+	// Tick our mock block subscription with the next block, we don't
+	// expect anything to happen.
+	currentHeight := uint32(testCurrentHeight + 1)
+	test.announceBlock(t, currentHeight)
+
+	// Now, we add another htlc to the invoice. This one has a lower expiry
+	// height than our current ones.
+	htlc2 := currentHeight + 5
+	expiry2 := makeHeightExpiry(test.hash, htlc2)
+	test.watcher.AddInvoices(expiry2)
+
+	// Announce our lowest htlc expiry block minus our delta, the invoice
+	// should be expired now.
+	test.announceBlock(t, htlc2-delta)
+	test.assertCanceled(t, test.hash)
+}

invoices/invoiceregistry.go

@@ -1118,6 +1118,16 @@ func (i *InvoiceRegistry) notifyExitHopHtlcLocked(
 
 		}
 
+		// If we have fully accepted the set of htlcs for this invoice,
+		// we can now add it to our invoice expiry watcher. We do not
+		// add invoices before they are fully accepted, because it is
+		// possible that we MppTimeout the htlcs, and then our relevant
+		// expiry height could change.
+		if res.outcome == resultAccepted {
+			expiry := makeInvoiceExpiry(ctx.hash, invoice)
+			i.expiryWatcher.AddInvoices(expiry)
+		}
+
 		i.hodlSubscribe(hodlChan, ctx.circuitKey)
 
 	default:

invoices/invoiceregistry_test.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/lightningnetwork/lnd/amp"
+	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/lntypes"
@@ -352,7 +353,11 @@ func TestSettleHoldInvoice(t *testing.T) {
 		FinalCltvRejectDelta: testFinalCltvRejectDelta,
 		Clock:                clock.NewTestClock(testTime),
 	}
-	registry := NewRegistry(cdb, NewInvoiceExpiryWatcher(cfg.Clock), &cfg)
+
+	expiryWatcher := NewInvoiceExpiryWatcher(
+		cfg.Clock, 0, uint32(testCurrentHeight), nil, newMockNotifier(),
+	)
+	registry := NewRegistry(cdb, expiryWatcher, &cfg)
 
 	err = registry.Start()
 	if err != nil {
@@ -521,7 +526,10 @@ func TestCancelHoldInvoice(t *testing.T) {
 		FinalCltvRejectDelta: testFinalCltvRejectDelta,
 		Clock:                clock.NewTestClock(testTime),
 	}
-	registry := NewRegistry(cdb, NewInvoiceExpiryWatcher(cfg.Clock), &cfg)
+	expiryWatcher := NewInvoiceExpiryWatcher(
+		cfg.Clock, 0, uint32(testCurrentHeight), nil, newMockNotifier(),
+	)
+	registry := NewRegistry(cdb, expiryWatcher, &cfg)
 
 	err = registry.Start()
 	if err != nil {
@@ -946,7 +954,9 @@ func TestInvoiceExpiryWithRegistry(t *testing.T) {
 		Clock:                testClock,
 	}
 
-	expiryWatcher := NewInvoiceExpiryWatcher(cfg.Clock)
+	expiryWatcher := NewInvoiceExpiryWatcher(
+		cfg.Clock, 0, uint32(testCurrentHeight), nil, newMockNotifier(),
+	)
 	registry := NewRegistry(cdb, expiryWatcher, &cfg)
 
 	// First prefill the Channel DB with some pre-existing invoices,
@@ -1049,7 +1059,9 @@ func TestOldInvoiceRemovalOnStart(t *testing.T) {
 		GcCanceledInvoicesOnStartup: true,
 	}
 
-	expiryWatcher := NewInvoiceExpiryWatcher(cfg.Clock)
+	expiryWatcher := NewInvoiceExpiryWatcher(
+		cfg.Clock, 0, uint32(testCurrentHeight), nil, newMockNotifier(),
+	)
 	registry := NewRegistry(cdb, expiryWatcher, &cfg)
 
 	// First prefill the Channel DB with some pre-existing expired invoices.
@@ -1107,6 +1119,222 @@ func TestOldInvoiceRemovalOnStart(t *testing.T) {
 	require.Equal(t, expected, response.Invoices)
 }
 
+// TestHeightExpiryWithRegistry tests our height-based invoice expiry for
+// invoices paid with single and multiple htlcs, testing the case where the
+// invoice is settled before expiry (and thus not canceled), and the case
+// where the invoice is expired.
+func TestHeightExpiryWithRegistry(t *testing.T) {
+	t.Run("single shot settled before expiry", func(t *testing.T) {
+		testHeightExpiryWithRegistry(t, 1, true)
+	})
+
+	t.Run("single shot expires", func(t *testing.T) {
+		testHeightExpiryWithRegistry(t, 1, false)
+	})
+
+	t.Run("mpp settled before expiry", func(t *testing.T) {
+		testHeightExpiryWithRegistry(t, 2, true)
+	})
+
+	t.Run("mpp expires", func(t *testing.T) {
+		testHeightExpiryWithRegistry(t, 2, false)
+	})
+}
+
+func testHeightExpiryWithRegistry(t *testing.T, numParts int, settle bool) {
+	t.Parallel()
+	defer timeout()()
+
+	ctx := newTestContext(t)
+	defer ctx.cleanup()
+
+	require.Greater(t, numParts, 0, "test requires at least one part")
+
+	// Add a hold invoice, we set a non-nil payment request so that this
+	// invoice is not considered a keysend by the expiry watcher.
+	invoice := *testInvoice
+	invoice.HodlInvoice = true
+	invoice.PaymentRequest = []byte{1, 2, 3}
+
+	_, err := ctx.registry.AddInvoice(&invoice, testInvoicePaymentHash)
+	require.NoError(t, err)
+
+	payLoad := testPayload
+	if numParts > 1 {
+		payLoad = &mockPayload{
+			mpp: record.NewMPP(testInvoiceAmt, [32]byte{}),
+		}
+	}
+
+	htlcAmt := invoice.Terms.Value / lnwire.MilliSatoshi(numParts)
+	hodlChan := make(chan interface{}, numParts)
+	for i := 0; i < numParts; i++ {
+		// We bump our expiry height for each htlc so that we can test
+		// that the lowest expiry height is used.
+		expiry := testHtlcExpiry + uint32(i)
+
+		resolution, err := ctx.registry.NotifyExitHopHtlc(
+			testInvoicePaymentHash, htlcAmt, expiry,
+			testCurrentHeight, getCircuitKey(uint64(i)), hodlChan,
+			payLoad,
+		)
+		require.NoError(t, err)
+		require.Nil(t, resolution, "did not expect direct resolution")
+	}
+
+	require.Eventually(t, func() bool {
+		inv, err := ctx.registry.LookupInvoice(testInvoicePaymentHash)
+		require.NoError(t, err)
+
+		return inv.State == channeldb.ContractAccepted
+	}, time.Second, time.Millisecond*100)
+
+	// Now that we've added our htlc(s), we tick our test clock to our
+	// invoice expiry time. We don't expect the invoice to be canceled
+	// based on its expiry time now that we have active htlcs.
+	ctx.clock.SetTime(invoice.CreationDate.Add(invoice.Terms.Expiry + 1))
+
+	// The expiry watcher loop takes some time to process the new clock
+	// time. We mine the block before our expiry height, our mock will block
+	// until the expiry watcher consumes this height, so we can be sure
+	// that the expiry loop has run at least once after this block is
+	// consumed.
+	ctx.notifier.blockChan <- &chainntnfs.BlockEpoch{
+		Height: int32(testHtlcExpiry - 1),
+	}
+
+	// If we want to settle our invoice in this test, we do so now.
+	if settle {
+		err = ctx.registry.SettleHodlInvoice(testInvoicePreimage)
+		require.NoError(t, err)
+
+		for i := 0; i < numParts; i++ {
+			htlcResolution := (<-hodlChan).(HtlcResolution)
+			require.NotNil(t, htlcResolution)
+			settleResolution := checkSettleResolution(
+				t, htlcResolution, testInvoicePreimage,
+			)
+			require.Equal(t, ResultSettled, settleResolution.Outcome)
+		}
+	}
+
+	// Now we mine our htlc's expiry height.
+	ctx.notifier.blockChan <- &chainntnfs.BlockEpoch{
+		Height: int32(testHtlcExpiry),
+	}
+
+	// If we did not settle the invoice before its expiry, we now expect
+	// a cancelation.
+	expectedState := channeldb.ContractSettled
+	if !settle {
+		expectedState = channeldb.ContractCanceled
+
+		htlcResolution := (<-hodlChan).(HtlcResolution)
+		require.NotNil(t, htlcResolution)
+		checkFailResolution(
+			t, htlcResolution, ResultCanceled,
+		)
+	}
+
+	// Finally, lookup the invoice and assert that we have the state we
+	// expect.
+	inv, err := ctx.registry.LookupInvoice(testInvoicePaymentHash)
+	require.NoError(t, err)
+	require.Equal(t, expectedState, inv.State, "expected "+
+		"hold invoice: %v, got: %v", expectedState, inv.State)
+}
+
+// TestMultipleSetHeightExpiry pays a hold invoice with two mpp sets, testing
+// that the invoice expiry watcher only uses the expiry height of the second,
+// successful set to cancel the invoice, and does not cancel early using the
+// expiry height of the first set that was canceled back due to mpp timeout.
+func TestMultipleSetHeightExpiry(t *testing.T) {
+	t.Parallel()
+	defer timeout()()
+
+	ctx := newTestContext(t)
+	defer ctx.cleanup()
+
+	// Add a hold invoice.
+	invoice := *testInvoice
+	invoice.HodlInvoice = true
+
+	_, err := ctx.registry.AddInvoice(&invoice, testInvoicePaymentHash)
+	require.NoError(t, err)
+
+	mppPayload := &mockPayload{
+		mpp: record.NewMPP(testInvoiceAmt, [32]byte{}),
+	}
+
+	// Send htlc 1.
+	hodlChan1 := make(chan interface{}, 1)
+	resolution, err := ctx.registry.NotifyExitHopHtlc(
+		testInvoicePaymentHash, invoice.Terms.Value/2,
+		testHtlcExpiry,
+		testCurrentHeight, getCircuitKey(10), hodlChan1, mppPayload,
+	)
+	require.NoError(t, err)
+	require.Nil(t, resolution, "did not expect direct resolution")
+
+	// Simulate mpp timeout releasing htlc 1.
+	ctx.clock.SetTime(testTime.Add(30 * time.Second))
+
+	htlcResolution := (<-hodlChan1).(HtlcResolution)
+	failResolution, ok := htlcResolution.(*HtlcFailResolution)
+	require.True(t, ok, "expected fail resolution, got: %T", resolution)
+	require.Equal(t, ResultMppTimeout, failResolution.Outcome,
+		"expected MPP Timeout, got: %v", failResolution.Outcome)
+
+	// Notify the expiry height for our first htlc. We don't expect the
+	// invoice to be expired based on block height because the htlc set
+	// was never completed.
+	ctx.notifier.blockChan <- &chainntnfs.BlockEpoch{
+		Height: int32(testHtlcExpiry),
+	}
+
+	// Now we will send a full set of htlcs for the invoice with a higher
+	// expiry height. We expect the invoice to move into the accepted state.
+	expiry := testHtlcExpiry + 5
+
+	// Send htlc 2.
+	hodlChan2 := make(chan interface{}, 1)
+	resolution, err = ctx.registry.NotifyExitHopHtlc(
+		testInvoicePaymentHash, invoice.Terms.Value/2, expiry,
+		testCurrentHeight, getCircuitKey(11), hodlChan2, mppPayload,
+	)
+	require.NoError(t, err)
+	require.Nil(t, resolution, "did not expect direct resolution")
+
+	// Send htlc 3.
+	hodlChan3 := make(chan interface{}, 1)
+	resolution, err = ctx.registry.NotifyExitHopHtlc(
+		testInvoicePaymentHash, invoice.Terms.Value/2, expiry,
+		testCurrentHeight, getCircuitKey(12), hodlChan3, mppPayload,
+	)
+	require.NoError(t, err)
+	require.Nil(t, resolution, "did not expect direct resolution")
+
+	// Assert that we've reached an accepted state because the invoice has
+	// been paid with a complete set.
+	inv, err := ctx.registry.LookupInvoice(testInvoicePaymentHash)
+	require.NoError(t, err)
+	require.Equal(t, channeldb.ContractAccepted, inv.State, "expected "+
+		"hold invoice accepted")
+
+	// Now we will notify the expiry height for the new set of htlcs. We
+	// expect the invoice to be canceled by the expiry watcher.
+	ctx.notifier.blockChan <- &chainntnfs.BlockEpoch{
+		Height: int32(expiry),
+	}
+
+	require.Eventuallyf(t, func() bool {
+		inv, err := ctx.registry.LookupInvoice(testInvoicePaymentHash)
+		require.NoError(t, err)
+
+		return inv.State == channeldb.ContractCanceled
+	}, testTimeout, time.Millisecond*100, "invoice not canceled")
+}
+
 // TestSettleInvoicePaymentAddrRequired tests that if an incoming payment has
 // an invoice that requires the payment addr bit to be set, and the incoming
 // payment doesn't include an mpp payload, then the payment is rejected.

invoices/test_utils_test.go

@@ -8,11 +8,13 @@ import (
 	"io/ioutil"
 	"os"
 	"runtime/pprof"
+	"sync"
 	"testing"
 	"time"
 
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/lntypes"
@@ -179,6 +181,7 @@ func newTestChannelDB(clock clock.Clock) (*channeldb.DB, func(), error) {
 type testContext struct {
 	cdb      *channeldb.DB
 	registry *InvoiceRegistry
+	notifier *mockChainNotifier
 	clock    *clock.TestClock
 
 	cleanup func()
@@ -193,7 +196,11 @@ func newTestContext(t *testing.T) *testContext {
 		t.Fatal(err)
 	}
 
-	expiryWatcher := NewInvoiceExpiryWatcher(clock)
+	notifier := newMockNotifier()
+
+	expiryWatcher := NewInvoiceExpiryWatcher(
+		clock, 0, uint32(testCurrentHeight), nil, notifier,
+	)
 
 	// Instantiate and start the invoice ctx.registry.
 	cfg := RegistryConfig{
@@ -212,6 +219,7 @@ func newTestContext(t *testing.T) *testContext {
 	ctx := testContext{
 		cdb:      cdb,
 		registry: registry,
+		notifier: notifier,
 		clock:    clock,
 		t:        t,
 		cleanup: func() {
@@ -365,3 +373,111 @@ func checkFailResolution(t *testing.T, res HtlcResolution,
 
 	return failResolution
 }
+
+type hodlExpiryTest struct {
+	hash         lntypes.Hash
+	state        channeldb.ContractState
+	stateLock    sync.Mutex
+	mockNotifier *mockChainNotifier
+	mockClock    *clock.TestClock
+	cancelChan   chan lntypes.Hash
+	watcher      *InvoiceExpiryWatcher
+}
+
+func (h *hodlExpiryTest) setState(state channeldb.ContractState) {
+	h.stateLock.Lock()
+	defer h.stateLock.Unlock()
+
+	h.state = state
+}
+
+func (h *hodlExpiryTest) announceBlock(t *testing.T, height uint32) {
+	select {
+	case h.mockNotifier.blockChan <- &chainntnfs.BlockEpoch{
+		Height: int32(height),
+	}:
+
+	case <-time.After(testTimeout):
+		t.Fatalf("block %v not consumed", height)
+	}
+}
+
+func (h *hodlExpiryTest) assertCanceled(t *testing.T, expected lntypes.Hash) {
+	select {
+	case actual := <-h.cancelChan:
+		require.Equal(t, expected, actual)
+
+	case <-time.After(testTimeout):
+		t.Fatalf("invoice: %v not canceled", h.hash)
+	}
+}
+
+// setupHodlExpiry creates a hodl invoice in our expiry watcher and runs an
+// arbitrary update function which advances the invoices's state.
+func setupHodlExpiry(t *testing.T, creationDate time.Time,
+	expiry time.Duration, heightDelta uint32,
+	startState channeldb.ContractState,
+	startHtlcs []*channeldb.InvoiceHTLC) *hodlExpiryTest {
+
+	mockNotifier := newMockNotifier()
+	mockClock := clock.NewTestClock(testTime)
+
+	test := &hodlExpiryTest{
+		state: startState,
+		watcher: NewInvoiceExpiryWatcher(
+			mockClock, heightDelta, uint32(testCurrentHeight), nil,
+			mockNotifier,
+		),
+		cancelChan:   make(chan lntypes.Hash),
+		mockNotifier: mockNotifier,
+		mockClock:    mockClock,
+	}
+
+	// Use an unbuffered channel to block on cancel calls so that the test
+	// does not exit before we've processed all the invoices we expect.
+	cancelImpl := func(paymentHash lntypes.Hash, force bool) error {
+		test.stateLock.Lock()
+		currentState := test.state
+		test.stateLock.Unlock()
+
+		if currentState != channeldb.ContractOpen && !force {
+			return nil
+		}
+
+		select {
+		case test.cancelChan <- paymentHash:
+		case <-time.After(testTimeout):
+		}
+
+		return nil
+	}
+
+	require.NoError(t, test.watcher.Start(cancelImpl))
+
+	// We set preimage and hash so that we can use our existing test
+	// helpers. In practice we would only have the hash, but this does not
+	// affect what we're testing at all.
+	preimage := lntypes.Preimage{1}
+	test.hash = preimage.Hash()
+
+	invoice := newTestInvoice(t, preimage, creationDate, expiry)
+	invoice.State = startState
+	invoice.HodlInvoice = true
+	invoice.Htlcs = make(map[channeldb.CircuitKey]*channeldb.InvoiceHTLC)
+
+	// If we have any htlcs, add them with unique circult keys.
+	for i, htlc := range startHtlcs {
+		key := channeldb.CircuitKey{
+			HtlcID: uint64(i),
+		}
+
+		invoice.Htlcs[key] = htlc
+	}
+
+	// Create an expiry entry for our invoice in its starting state. This
+	// mimics adding invoices to the watcher on start.
+	entry := makeInvoiceExpiry(test.hash, invoice)
+	test.watcher.AddInvoices(entry)
+
+	return test
+}

lncfg/invoices.go

@@ -0,0 +1,12 @@
+package lncfg
+
+// DefaultHoldInvoiceExpiryDelta defines the number of blocks before the expiry
+// height of a hold invoice's htlc that lnd will automatically cancel the
+// invoice to prevent the channel from force closing. This value *must* be
+// greater than DefaultIncomingBroadcastDelta to prevent force closes.
+const DefaultHoldInvoiceExpiryDelta = DefaultIncomingBroadcastDelta + 2
+
+// Invoices holds the configuration options for invoices.
+type Invoices struct {
+	HoldExpiryDelta uint32 `long:"holdexpirydelta" description:"The number of blocks before a hold invoice's htlc expires that the invoice should be canceled to prevent a force close. Force closes will not be prevented if this value is not greater than DefaultIncomingBroadcastDelta."`
+}

lntest/itest/lnd_hold_invoice_force_test.go

@@ -14,9 +14,8 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-// testHoldInvoiceForceClose demonstrates that recipients of hold invoices
+// testHoldInvoiceForceClose tests cancelation of accepted hold invoices which
-// will not release active htlcs for their own invoices when they expire,
+// would otherwise trigger force closes when they expire.
-// resulting in a force close of their channel.
 func testHoldInvoiceForceClose(net *lntest.NetworkHarness, t *harnessTest) {
 	ctxb, cancel := context.WithCancel(context.Background())
 	defer cancel()
@@ -94,38 +93,43 @@ func testHoldInvoiceForceClose(net *lntest.NetworkHarness, t *harnessTest) {
 	require.NoError(t.t, net.Alice.WaitForBlockchainSync(ctxb))
 	require.NoError(t.t, net.Bob.WaitForBlockchainSync(ctxb))
 
-	// Alice should have a waiting-close channel because she has force
+	// Our channel should not have been force closed, instead we expect our
-	// closed to time out the htlc.
+	// channel to still be open and our invoice to have been canceled before
-	assertNumPendingChannels(t, net.Alice, 1, 0)
+	// expiry.
-
-	// We should have our force close tx in the mempool.
-	mineBlocks(t, net, 1, 1)
-
-	// Ensure alice and bob are synced to chain after we've mined our force
-	// close.
-	require.NoError(t.t, net.Alice.WaitForBlockchainSync(ctxb))
-	require.NoError(t.t, net.Bob.WaitForBlockchainSync(ctxb))
-
-	// At this point, Bob's channel should be resolved because his htlc is
-	// expired, so no further action is required. Alice will still have a
-	// pending force close channel because she needs to resolve the htlc.
-	assertNumPendingChannels(t, net.Alice, 0, 1)
-	assertNumPendingChannels(t, net.Bob, 0, 0)
-
 	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
-	err = waitForNumChannelPendingForceClose(ctxt, net.Alice, 1,
+	chanInfo, err := getChanInfo(ctxt, net.Alice)
-		func(channel *lnrpcForceCloseChannel) error {
+	require.NoError(t.t, err)
-			numHtlcs := len(channel.PendingHtlcs)
+
-			if numHtlcs != 1 {
+	fundingTxID, err := lnrpc.GetChanPointFundingTxid(chanPoint)
-				return fmt.Errorf("expected 1 htlc, got: "+
+	require.NoError(t.t, err)
-					"%v", numHtlcs)
+	chanStr := fmt.Sprintf("%v:%v", fundingTxID, chanPoint.OutputIndex)
+	require.Equal(t.t, chanStr, chanInfo.ChannelPoint)
+
+	err = wait.NoError(func() error {
+		inv, err := net.Bob.LookupInvoice(ctxt, &lnrpc.PaymentHash{
+			RHash: payHash[:],
+		})
+		if err != nil {
+			return err
+		}
+
+		if inv.State != lnrpc.Invoice_CANCELED {
+			return fmt.Errorf("expected canceled invoice, got: %v",
+				inv.State)
+		}
+
+		for _, htlc := range inv.Htlcs {
+			if htlc.State != lnrpc.InvoiceHTLCState_CANCELED {
+				return fmt.Errorf("expected htlc canceled, "+
+					"got: %v", htlc.State)
+			}
 		}
 
 		return nil
-		},
+	}, defaultTimeout)
-	)
+	require.NoError(t.t, err, "expected canceled invoice")
-	require.NoError(t.t, err)
 
-	// Cleanup Alice's force close.
+	// Clean up the channel.
-	cleanupForceClose(t, net, net.Alice, chanPoint)
+	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
+	closeChannelAndAssert(ctxt, t, net, net.Alice, chanPoint, false)
 }

lntest/itest/lnd_multi-hop_remote_force_close_on_chain_htlc_timeout_test.go

@@ -178,8 +178,8 @@ func testMultiHopRemoteForceCloseOnChainHtlcTimeout(net *lntest.NetworkHarness,
 	err = waitForNumChannelPendingForceClose(ctxt, bob, 0, nil)
 	require.NoError(t.t, err)
 
-	// While we're here, we demonstrate some bugs in our handling of
+	// While we're here, we assert that our expired invoice's state is
-	// invoices that timeout on chain.
+	// correctly updated, and can no longer be settled.
 	assertOnChainInvoiceState(ctxb, t, carol, preimage)
 
 	// We'll close out the test by closing the channel from Alice to Bob,
@@ -191,12 +191,8 @@ func testMultiHopRemoteForceCloseOnChainHtlcTimeout(net *lntest.NetworkHarness,
 	)
 }
 
-// assertOnChainInvoiceState asserts that we have some bugs with how we handle
+// assertOnChainInvoiceState asserts that we have the correct state for a hold
-// hold invoices that are expired on-chain.
+// invoice that has expired on chain, and that it can't be settled.
-// - htlcs accepted: despite being timed out, our htlcs are still in accepted
-//   state
-// - can settle: our invoice that has expired on-chain can still be settled
-//   even though we don't claim any htlcs.
 func assertOnChainInvoiceState(ctx context.Context, t *harnessTest,
 	node *lntest.HarnessNode, preimage lntypes.Preimage) {
 
@@ -207,22 +203,12 @@ func assertOnChainInvoiceState(ctx context.Context, t *harnessTest,
 	require.NoError(t.t, err)
 
 	for _, htlc := range inv.Htlcs {
-		require.Equal(t.t, lnrpc.InvoiceHTLCState_ACCEPTED, htlc.State)
+		require.Equal(t.t, lnrpc.InvoiceHTLCState_CANCELED, htlc.State)
 	}
+	require.Equal(t.t, lnrpc.Invoice_CANCELED, inv.State)
 
 	_, err = node.SettleInvoice(ctx, &invoicesrpc.SettleInvoiceMsg{
 		Preimage: preimage[:],
 	})
-	require.NoError(t.t, err, "expected erroneous invoice settle")
+	require.Error(t.t, err, "should not be able to settle invoice")
-
-	inv, err = node.LookupInvoice(ctx, &lnrpc.PaymentHash{
-		RHash: hash[:],
-	})
-	require.NoError(t.t, err)
-
-	require.True(t.t, inv.Settled, "expected erroneously settled invoice") // nolint:staticcheck
-	for _, htlc := range inv.Htlcs {
-		require.Equal(t.t, lnrpc.InvoiceHTLCState_SETTLED, htlc.State,
-			"expected htlcs to be erroneously settled")
-	}
 }

lntest/itest/log_error_whitelist.txt

@@ -279,3 +279,5 @@
 <time> [ERR] RPCS: [/lnrpc.State/SubscribeState]: context canceled
 <time> [ERR] NTFN: Failed to update rescan progress: database not open
 <time> [ERR] HSWC: ChannelLink(<chan>): failing link: process hodl queue: unable to update commitment: link shutting down with error: internal error
+<time> [ERR] INVC: SettleHodlInvoice with preimage <hex>: invoice already canceled
+<time> [ERR] RPCS: [/invoicesrpc.Invoices/SettleInvoice]: invoice already canceled

sample-lnd.conf

@@ -1129,3 +1129,23 @@ litecoin.node=ltcd
 ; will accept over the channel update interval.
 ; gossip.max-channel-update-burst=10
 ; gossip.channel-update-interval=1m
+
+[invoices]
+; If a hold invoice has accepted htlcs that reach their expiry height and are 
+; not timed out, the channel holding the htlc is force closed to resolve the
+; invoice's htlcs. To prevent force closes, lnd automatically cancels these 
+; invoices before they reach their expiry height.
+;
+; Hold expiry delta describes the number of blocks before expiry that these 
+; invoices should be canceled. Setting this value to 0 will ensure that hold
+; invoices can be settled right up until their expiry height, but will result
+; in the channel they are on being force closed if they are not resolved before
+; expiry.
+; 
+; Lnd goes to chain before the expiry for a htlc is reached so that there is 
+; time to resolve it on chain. This value needs to be greater than the 
+; DefaultIncomingBroadcastDelta set by lnd, otherwise the channel will be force
+; closed anyway. A warning will be logged on startup if this value is not large
+; enough to prevent force closes.
+;
+; invoices.holdexpirydelta=15

server.go

@@ -443,11 +443,6 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		readPool:       readPool,
 		chansToRestore: chansToRestore,
 
-		invoices: invoices.NewRegistry(
-			remoteChanDB, invoices.NewInvoiceExpiryWatcher(clock.NewDefaultClock()),
-			&registryConfig,
-		),
-
 		channelNotifier: channelnotifier.New(remoteChanDB),
 
 		identityECDH: nodeKeyECDH,
@@ -484,11 +479,19 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		subscribers: make(map[uint64]*preimageSubscriber),
 	}
 
-	_, currentHeight, err := s.cc.ChainIO.GetBestBlock()
+	currentHash, currentHeight, err := s.cc.ChainIO.GetBestBlock()
 	if err != nil {
 		return nil, err
 	}
 
+	expiryWatcher := invoices.NewInvoiceExpiryWatcher(
+		clock.NewDefaultClock(), cfg.Invoices.HoldExpiryDelta,
+		uint32(currentHeight), currentHash, cc.ChainNotifier,
+	)
+	s.invoices = invoices.NewRegistry(
+		remoteChanDB, expiryWatcher, &registryConfig,
+	)
+
 	s.htlcNotifier = htlcswitch.NewHtlcNotifier(time.Now)
 
 	s.htlcSwitch, err = htlcswitch.New(htlcswitch.Config{