loopout: allow multi-loop

lndclient/router_client.go

@@ -93,6 +93,10 @@ type SendPaymentRequest struct {
 	// LastHopPubkey is the pubkey of the last hop of the route taken
 	// for this payment. If empty, any hop may be used.
 	LastHopPubkey *route.Vertex
+
+	// The maximum number of partial payments that may be used to complete
+	// the full amount.
+	MaxShards uint32
 }
 
 // routerClient is a wrapper around the generated routerrpc proxy.
@@ -120,6 +124,7 @@ func (r *routerClient) SendPayment(ctx context.Context,
 		FeeLimitSat:    int64(request.MaxFee),
 		PaymentRequest: request.Invoice,
 		TimeoutSeconds: int32(request.Timeout.Seconds()),
+		MaxShards:      request.MaxShards,
 	}
 	if request.MaxCltv != nil {
 		rpcReq.CltvLimit = *request.MaxCltv

loopout.go

@@ -41,6 +41,12 @@ var (
 	paymentTimeout = time.Minute
 )
 
+const (
+	// loopOutMaxShards defines that maximum number of shards that may be
+	// used for a loop out swap.
+	loopOutMaxShards = 5
+)
+
 // loopOutSwap contains all the in-memory state related to a pending loop out
 // swap.
 type loopOutSwap struct {
@@ -452,6 +458,7 @@ func (s *loopOutSwap) payInvoiceAsync(ctx context.Context,
 		Invoice:         invoice,
 		OutgoingChannel: outgoingChannel,
 		Timeout:         paymentTimeout,
+		MaxShards:       loopOutMaxShards,
 	}
 
 	// Lookup state of the swap payment.