multi: use wire records on payment and intercept flows

routing/payment_lifecycle.go

@@ -25,12 +25,13 @@ var ErrPaymentLifecycleExiting = errors.New("payment lifecycle exiting")
 // paymentLifecycle holds all information about the current state of a payment
 // needed to resume if from any point.
 type paymentLifecycle struct {
-	router        *ChannelRouter
-	feeLimit      lnwire.MilliSatoshi
-	identifier    lntypes.Hash
-	paySession    PaymentSession
-	shardTracker  shards.ShardTracker
-	currentHeight int32
+	router                *ChannelRouter
+	feeLimit              lnwire.MilliSatoshi
+	identifier            lntypes.Hash
+	paySession            PaymentSession
+	shardTracker          shards.ShardTracker
+	currentHeight         int32
+	firstHopCustomRecords lnwire.CustomRecords
 
 	// quit is closed to signal the sub goroutines of the payment lifecycle
 	// to stop.
@@ -52,18 +53,19 @@ type paymentLifecycle struct {
 // newPaymentLifecycle initiates a new payment lifecycle and returns it.
 func newPaymentLifecycle(r *ChannelRouter, feeLimit lnwire.MilliSatoshi,
 	identifier lntypes.Hash, paySession PaymentSession,
-	shardTracker shards.ShardTracker,
-	currentHeight int32) *paymentLifecycle {
+	shardTracker shards.ShardTracker, currentHeight int32,
+	firstHopCustomRecords lnwire.CustomRecords) *paymentLifecycle {
 
 	p := &paymentLifecycle{
-		router:          r,
-		feeLimit:        feeLimit,
-		identifier:      identifier,
-		paySession:      paySession,
-		shardTracker:    shardTracker,
-		currentHeight:   currentHeight,
-		quit:            make(chan struct{}),
-		resultCollected: make(chan error, 1),
+		router:                r,
+		feeLimit:              feeLimit,
+		identifier:            identifier,
+		paySession:            paySession,
+		shardTracker:          shardTracker,
+		currentHeight:         currentHeight,
+		quit:                  make(chan struct{}),
+		resultCollected:       make(chan error, 1),
+		firstHopCustomRecords: firstHopCustomRecords,
 	}
 
 	// Mount the result collector.
@@ -677,9 +679,10 @@ func (p *paymentLifecycle) sendAttempt(
 	// this packet will be used to route the payment through the network,
 	// starting with the first-hop.
 	htlcAdd := &lnwire.UpdateAddHTLC{
-		Amount:      rt.TotalAmount,
-		Expiry:      rt.TotalTimeLock,
-		PaymentHash: *attempt.Hash,
+		Amount:        rt.TotalAmount,
+		Expiry:        rt.TotalTimeLock,
+		PaymentHash:   *attempt.Hash,
+		CustomRecords: p.firstHopCustomRecords,
 	}
 
 	// Generate the raw encoded sphinx packet to be included along

routing/payment_lifecycle_test.go

@@ -89,7 +89,7 @@ func newTestPaymentLifecycle(t *testing.T) (*paymentLifecycle, *mockers) {
 	// Create a test payment lifecycle with no fee limit and no timeout.
 	p := newPaymentLifecycle(
 		rt, noFeeLimit, paymentHash, mockPaymentSession,
-		mockShardTracker, 0,
+		mockShardTracker, 0, nil,
 	)
 
 	// Create a mock payment which is returned from mockControlTower.

routing/router.go

@@ -865,6 +865,11 @@ type LightningPayment struct {
 	// fail.
 	DestCustomRecords record.CustomSet
 
+	// FirstHopCustomRecords are the TLV records that are to be sent to the
+	// first hop of this payment. These records will be transmitted via the
+	// wire message and therefore do not affect the onion payload size.
+	FirstHopCustomRecords lnwire.CustomRecords
+
 	// MaxParts is the maximum number of partial payments that may be used
 	// to complete the full amount.
 	MaxParts uint32
@@ -948,6 +953,7 @@ func (r *ChannelRouter) SendPayment(payment *LightningPayment) ([32]byte,
 	return r.sendPayment(
 		context.Background(), payment.FeeLimit, payment.Identifier(),
 		payment.PayAttemptTimeout, paySession, shardTracker,
+		payment.FirstHopCustomRecords,
 	)
 }
 
@@ -968,6 +974,7 @@ func (r *ChannelRouter) SendPaymentAsync(ctx context.Context,
 		_, _, err := r.sendPayment(
 			ctx, payment.FeeLimit, payment.Identifier(),
 			payment.PayAttemptTimeout, ps, st,
+			payment.FirstHopCustomRecords,
 		)
 		if err != nil {
 			log.Errorf("Payment %x failed: %v",
@@ -1141,7 +1148,9 @@ func (r *ChannelRouter) sendToRoute(htlcHash lntypes.Hash, rt *route.Route,
 	// - nil payment session (since we already have a route).
 	// - no payment timeout.
 	// - no current block height.
-	p := newPaymentLifecycle(r, 0, paymentIdentifier, nil, shardTracker, 0)
+	p := newPaymentLifecycle(
+		r, 0, paymentIdentifier, nil, shardTracker, 0, nil,
+	)
 
 	// We found a route to try, create a new HTLC attempt to try.
 	//
@@ -1237,7 +1246,9 @@ func (r *ChannelRouter) sendToRoute(htlcHash lntypes.Hash, rt *route.Route,
 func (r *ChannelRouter) sendPayment(ctx context.Context,
 	feeLimit lnwire.MilliSatoshi, identifier lntypes.Hash,
 	paymentAttemptTimeout time.Duration, paySession PaymentSession,
-	shardTracker shards.ShardTracker) ([32]byte, *route.Route, error) {
+	shardTracker shards.ShardTracker,
+	firstHopCustomRecords lnwire.CustomRecords) ([32]byte, *route.Route,
+	error) {
 
 	// If the user provides a timeout, we will additionally wrap the context
 	// in a deadline.
@@ -1262,7 +1273,7 @@ func (r *ChannelRouter) sendPayment(ctx context.Context,
 	// can resume the payment from the current state.
 	p := newPaymentLifecycle(
 		r, feeLimit, identifier, paySession, shardTracker,
-		currentHeight,
+		currentHeight, firstHopCustomRecords,
 	)
 
 	return p.resumePayment(ctx)
@@ -1465,7 +1476,7 @@ func (r *ChannelRouter) resumePayments() error {
 		noTimeout := time.Duration(0)
 		_, _, err := r.sendPayment(
 			context.Background(), 0, payHash, noTimeout, paySession,
-			shardTracker,
+			shardTracker, nil,
 		)
 		if err != nil {
 			log.Errorf("Resuming payment %v failed: %v", payHash,