multi: improve logging

htlcswitch/link.go

@@ -2052,6 +2052,9 @@ func (l *channelLink) cleanupSpuriousResponse(pkt *htlcPacket) {
 func (l *channelLink) handleUpstreamMsg(ctx context.Context,
 	msg lnwire.Message) {
 
+	l.log.Tracef("receive upstream msg %v, handling now... ", msg.MsgType())
+	defer l.log.Tracef("handled upstream msg %v", msg.MsgType())
+
 	// First check if the message is an update and we are capable of
 	// receiving updates right now.
 	if msg.MsgType().IsChannelUpdate() && !l.quiescer.CanRecvUpdates() {

htlcswitch/switch.go

@@ -2243,6 +2243,9 @@ func (s *Switch) getLinkByMapping(pkt *htlcPacket) (ChannelLink, error) {
 	chanID := pkt.outgoingChanID
 	aliasID := s.cfg.IsAlias(chanID)
 
+	log.Debugf("Querying outgoing link using chanID=%v, aliasID=%v", chanID,
+		aliasID)
+
 	// Set the originalOutgoingChanID so the proper channel_update can be
 	// sent back if the option-scid-alias feature bit was negotiated.
 	pkt.originalOutgoingChanID = chanID
@@ -2299,6 +2302,9 @@ func (s *Switch) getLinkByMapping(pkt *htlcPacket) (ChannelLink, error) {
 	// forward over it and this is a channel where the option-scid-alias
 	// feature bit was negotiated.
 	if link.IsUnadvertised() {
+		log.Debugf("Link is unadvertised, chanID=%v, baseScid=%v",
+			chanID, baseScid)
+
 		return nil, ErrChannelLinkNotFound
 	}