invoicesrpc: add HTLC modifier to invoices RPC server

This commit integrates the HTLC modifier service into the
invoices RPC server.

lnd.go

@@ -638,6 +638,7 @@ func Main(cfg *Config, lisCfg ListenerCfg, implCfg *ImplementationCfg,
 	err = rpcServer.addDeps(
 		server, interceptorChain.MacaroonService(), cfg.SubRPCServers,
 		atplManager, server.invoices, tower, multiAcceptor,
+		server.invoiceHtlcModifier,
 	)
 	if err != nil {
 		return mkErr("unable to add deps to RPC server: %v", err)

lnrpc/invoicesrpc/config_active.go

@@ -30,6 +30,11 @@ type Config struct {
 	// created by the daemon.
 	InvoiceRegistry *invoices.InvoiceRegistry
 
+	// HtlcModifier is a service which intercepts invoice HTLCs during the
+	// settlement phase, enabling a subscribed client to modify certain
+	// aspects of those HTLCs.
+	HtlcModifier invoices.HtlcModifier
+
 	// IsChannelActive is used to generate valid hop hints.
 	IsChannelActive func(chanID lnwire.ChannelID) bool
 

rpcserver.go

@@ -684,7 +684,8 @@ func newRPCServer(cfg *Config, interceptorChain *rpcperms.InterceptorChain,
 func (r *rpcServer) addDeps(s *server, macService *macaroons.Service,
 	subServerCgs *subRPCServerConfigs, atpl *autopilot.Manager,
 	invoiceRegistry *invoices.InvoiceRegistry, tower *watchtower.Standalone,
-	chanPredicate chanacceptor.MultiplexAcceptor) error {
+	chanPredicate chanacceptor.MultiplexAcceptor,
+	invoiceHtlcModifier *invoices.HtlcModificationInterceptor) error {
 
 	// Set up router rpc backend.
 	selfNode, err := s.graphDB.SourceNode()
@@ -787,7 +788,7 @@ func (r *rpcServer) addDeps(s *server, macService *macaroons.Service,
 		s.sweeper, tower, s.towerClientMgr, r.cfg.net.ResolveTCPAddr,
 		genInvoiceFeatures, genAmpInvoiceFeatures,
 		s.getNodeAnnouncement, s.updateAndBrodcastSelfNode, parseAddr,
-		rpcsLog, s.aliasMgr,
+		rpcsLog, s.aliasMgr, invoiceHtlcModifier,
 	)
 	if err != nil {
 		return err

subrpcserver_config.go

@@ -122,7 +122,8 @@ func (s *subRPCServerConfigs) PopulateDependencies(cfg *Config,
 	updateNodeAnnouncement func(features *lnwire.RawFeatureVector,
 		modifiers ...netann.NodeAnnModifier) error,
 	parseAddr func(addr string) (net.Addr, error),
-	rpcLogger btclog.Logger, aliasMgr *aliasmgr.Manager) error {
+	rpcLogger btclog.Logger, aliasMgr *aliasmgr.Manager,
+	invoiceHtlcModifier *invoices.HtlcModificationInterceptor) error {
 
 	// First, we'll use reflect to obtain a version of the config struct
 	// that allows us to programmatically inspect its fields.
@@ -241,6 +242,9 @@ func (s *subRPCServerConfigs) PopulateDependencies(cfg *Config,
 			subCfgValue.FieldByName("InvoiceRegistry").Set(
 				reflect.ValueOf(invoiceRegistry),
 			)
+			subCfgValue.FieldByName("HtlcModifier").Set(
+				reflect.ValueOf(invoiceHtlcModifier),
+			)
 			subCfgValue.FieldByName("IsChannelActive").Set(
 				reflect.ValueOf(htlcSwitch.HasActiveLink),
 			)