multi: report blinded path receives to Mission Control

in the new "blinded-paths" namespace.

invoices/interface.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"time"
 
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/lightningnetwork/lnd/channeldb/models"
 	"github.com/lightningnetwork/lnd/lntypes"
@@ -114,6 +115,10 @@ type Payload interface {
 	// TotalAmtMsat returns the total amount sent to the final hop, as set
 	// by the payee.
 	TotalAmtMsat() lnwire.MilliSatoshi
+
+	// BlindingPoint returns the route blinding point parsed from the onion
+	// payload.
+	BlindingPoint() *btcec.PublicKey
 }
 
 // InvoiceQuery represents a query to the invoice database. The query allows a

invoices/invoiceregistry.go

@@ -8,11 +8,13 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/lightningnetwork/lnd/channeldb/models"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/queue"
 	"github.com/lightningnetwork/lnd/record"
+	"github.com/lightningnetwork/lnd/routing/route"
 )
 
 var (
@@ -74,6 +76,11 @@ type RegistryConfig struct {
 	// KeysendHoldTime indicates for how long we want to accept and hold
 	// spontaneous keysend payments.
 	KeysendHoldTime time.Duration
+
+	// ReportBlindedPathReceive can be used to indicate the successful
+	// receive along a chosen blinded path.
+	ReportBlindedPathReceive func(invoiceAddIndex uint64,
+		rt *models.MCRoute) error
 }
 
 // htlcReleaseEvent describes an htlc auto-release event. It is used to release
@@ -931,6 +938,7 @@ func (i *InvoiceRegistry) NotifyExitHopHtlc(rHash lntypes.Hash,
 		metadata:             payload.Metadata(),
 		pathID:               payload.PathID(),
 		totalAmtMsat:         payload.TotalAmtMsat(),
+		blindingPoint:        payload.BlindingPoint(),
 	}
 
 	switch {
@@ -1024,9 +1032,13 @@ func (i *InvoiceRegistry) notifyExitHopHtlcLocked(
 	var (
 		resolution        HtlcResolution
 		updateSubscribers bool
+		blindedPath       *models.BlindedPathInfo
+		addIndex          uint64
 	)
 
 	callback := func(inv *Invoice) (*InvoiceUpdateDesc, error) {
+		addIndex = inv.AddIndex
+
 		updateDesc, res, err := updateInvoice(ctx, inv)
 		if err != nil {
 			return nil, err
@@ -1039,6 +1051,24 @@ func (i *InvoiceRegistry) notifyExitHopHtlcLocked(
 		// Assign resolution to outer scope variable.
 		resolution = res
 
+		if ctx.blindingPoint == nil {
+			return updateDesc, nil
+		}
+
+		// If this invoice was created before we started persisting the
+		// blinded path info for an invoice, exit.
+		if inv.BlindedPaths == nil {
+			return updateDesc, nil
+		}
+
+		path, ok := inv.BlindedPaths[route.NewVertex(ctx.blindingPoint)]
+		if !ok {
+			return nil, fmt.Errorf("expected a blinding path " +
+				"matching the received ephemeral key")
+		}
+
+		blindedPath = path
+
 		return updateDesc, nil
 	}
 
@@ -1078,6 +1108,18 @@ func (i *InvoiceRegistry) notifyExitHopHtlcLocked(
 		return nil, nil, err
 	}
 
+	if blindedPath != nil {
+		// Regardless of what we will do with the HTLC, we want to
+		// report to mission control that the blinded path route it
+		// chose successfully reached us.
+		err = i.cfg.ReportBlindedPathReceive(
+			addIndex, blindedPath.Route,
+		)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+
 	var invoiceToExpire invoiceExpiry
 
 	switch res := resolution.(type) {

invoices/test_utils_test.go

@@ -46,6 +46,10 @@ func (p *mockPayload) PathID() *chainhash.Hash {
 	return p.pathID
 }
 
+func (p *mockPayload) BlindingPoint() *btcec.PublicKey {
+	return nil
+}
+
 func (p *mockPayload) TotalAmtMsat() lnwire.MilliSatoshi {
 	return p.totalAmtMsat
 }

invoices/update.go

@@ -5,6 +5,7 @@ import (
 	"encoding/hex"
 	"errors"
 
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/lightningnetwork/lnd/amp"
 	"github.com/lightningnetwork/lnd/lntypes"
@@ -27,6 +28,7 @@ type invoiceUpdateCtx struct {
 	metadata             []byte
 	pathID               *chainhash.Hash
 	totalAmtMsat         lnwire.MilliSatoshi
+	blindingPoint        *btcec.PublicKey
 }
 
 // invoiceRef returns an identifier that can be used to lookup or update the

routing/missioncontrol_test.go

@@ -151,7 +151,9 @@ func (ctx *mcTestContext) reportFailure(amt lnwire.MilliSatoshi,
 
 // reportSuccess reports a success by using a test route.
 func (ctx *mcTestContext) reportSuccess() {
-	err := ctx.mc.ReportPaymentSuccess(ctx.pid, mcTestRoute)
+	err := ctx.mc.ReportPaymentSuccess(
+		ctx.pid, mcTestRoute,
+	)
 	if err != nil {
 		ctx.t.Fatal(err)
 	}

server.go

@@ -559,17 +559,6 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		return nil, err
 	}
 
-	registryConfig := invoices.RegistryConfig{
-		FinalCltvRejectDelta:        lncfg.DefaultFinalCltvRejectDelta,
-		HtlcHoldDuration:            invoices.DefaultHtlcHoldDuration,
-		Clock:                       clock.NewDefaultClock(),
-		AcceptKeySend:               cfg.AcceptKeySend,
-		AcceptAMP:                   cfg.AcceptAMP,
-		GcCanceledInvoicesOnStartup: cfg.GcCanceledInvoicesOnStartup,
-		GcCanceledInvoicesOnTheFly:  cfg.GcCanceledInvoicesOnTheFly,
-		KeysendHoldTime:             cfg.KeysendHoldTime,
-	}
-
 	s := &server{
 		cfg:            cfg,
 		graphDB:        dbs.GraphDB.ChannelGraph(),
@@ -628,14 +617,6 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		return nil, err
 	}
 
-	expiryWatcher := invoices.NewInvoiceExpiryWatcher(
-		clock.NewDefaultClock(), cfg.Invoices.HoldExpiryDelta,
-		uint32(currentHeight), currentHash, cc.ChainNotifier,
-	)
-	s.invoices = invoices.NewRegistry(
-		dbs.InvoiceDB, expiryWatcher, &registryConfig,
-	)
-
 	s.htlcNotifier = htlcswitch.NewHtlcNotifier(time.Now)
 
 	thresholdSats := btcutil.Amount(cfg.MaxFeeExposure)
@@ -950,6 +931,34 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 			"default namespace: %w", err)
 	}
 
+	blindedPathMC, err := s.missionController.GetNamespacedStore(
+		"blinded-path",
+	)
+	if err != nil {
+		return nil, fmt.Errorf("can't create mission control in the "+
+			"blinded path namespace: %w", err)
+	}
+
+	registryConfig := invoices.RegistryConfig{
+		FinalCltvRejectDelta:        lncfg.DefaultFinalCltvRejectDelta,
+		HtlcHoldDuration:            invoices.DefaultHtlcHoldDuration,
+		Clock:                       clock.NewDefaultClock(),
+		AcceptKeySend:               cfg.AcceptKeySend,
+		AcceptAMP:                   cfg.AcceptAMP,
+		GcCanceledInvoicesOnStartup: cfg.GcCanceledInvoicesOnStartup,
+		GcCanceledInvoicesOnTheFly:  cfg.GcCanceledInvoicesOnTheFly,
+		KeysendHoldTime:             cfg.KeysendHoldTime,
+		ReportBlindedPathReceive:    blindedPathMC.ReportPaymentSuccess,
+	}
+
+	expiryWatcher := invoices.NewInvoiceExpiryWatcher(
+		clock.NewDefaultClock(), cfg.Invoices.HoldExpiryDelta,
+		uint32(currentHeight), currentHash, cc.ChainNotifier,
+	)
+	s.invoices = invoices.NewRegistry(
+		dbs.InvoiceDB, expiryWatcher, &registryConfig,
+	)
+
 	srvrLog.Debugf("Instantiating payment session source with config: "+
 		"AttemptCost=%v + %v%%, MinRouteProbability=%v",
 		int64(routingConfig.AttemptCost),