switch: notify the ChannelNotifier on newly active/inactive channels.

htlcswitch/mock.go

@@ -162,9 +162,11 @@ func initSwitchWithDB(startingHeight uint32, db *channeldb.DB) (*Switch, error)
 		FetchLastChannelUpdate: func(lnwire.ShortChannelID) (*lnwire.ChannelUpdate, error) {
 			return nil, nil
 		},
-		Notifier:       &mockNotifier{},
-		FwdEventTicker: ticker.MockNew(DefaultFwdEventInterval),
-		LogEventTicker: ticker.MockNew(DefaultLogInterval),
+		Notifier:              &mockNotifier{},
+		FwdEventTicker:        ticker.MockNew(DefaultFwdEventInterval),
+		LogEventTicker:        ticker.MockNew(DefaultLogInterval),
+		NotifyActiveChannel:   func(wire.OutPoint) {},
+		NotifyInactiveChannel: func(wire.OutPoint) {},
 	}
 
 	return New(cfg, startingHeight)

htlcswitch/switch.go

@@ -175,6 +175,11 @@ type Config struct {
 	// LogEventTicker is a signal instructing the htlcswitch to log
 	// aggregate stats about it's forwarding during the last interval.
 	LogEventTicker ticker.Ticker
+
+	// NotifyActiveChannel and NotifyInactiveChannel allow the link to tell
+	// the ChannelNotifier when channels become active and inactive.
+	NotifyActiveChannel   func(wire.OutPoint)
+	NotifyInactiveChannel func(wire.OutPoint)
 }
 
 // Switch is the central messaging bus for all incoming/outgoing HTLCs.
@@ -1956,6 +1961,11 @@ func (s *Switch) addLiveLink(link ChannelLink) {
 		s.interfaceIndex[peerPub] = make(map[lnwire.ChannelID]ChannelLink)
 	}
 	s.interfaceIndex[peerPub][link.ChanID()] = link
+
+	// Inform the channel notifier if the link has become active.
+	if link.EligibleToForward() {
+		s.cfg.NotifyActiveChannel(*link.ChannelPoint())
+	}
 }
 
 // GetLink is used to initiate the handling of the get link command. The
@@ -2031,6 +2041,9 @@ func (s *Switch) removeLink(chanID lnwire.ChannelID) ChannelLink {
 		return nil
 	}
 
+	// Inform the Channel Notifier about the link becoming inactive.
+	s.cfg.NotifyInactiveChannel(*link.ChannelPoint())
+
 	// Remove the channel from live link indexes.
 	delete(s.pendingLinkIndex, link.ChanID())
 	delete(s.linkIndex, link.ChanID())

server.go

@@ -362,6 +362,8 @@ func newServer(listenAddrs []net.Addr, chanDB *channeldb.DB, cc *chainControl,
 			htlcswitch.DefaultFwdEventInterval),
 		LogEventTicker: ticker.New(
 			htlcswitch.DefaultLogInterval),
+		NotifyActiveChannel:   s.channelNotifier.NotifyActiveChannelEvent,
+		NotifyInactiveChannel: s.channelNotifier.NotifyInactiveChannelEvent,
 	}, uint32(currentHeight))
 	if err != nil {
 		return nil, err