htlcswitch: notify send forward failures and settles

Add notifications for local initiated sends settles and forwarding
failures. As with link failures, local send settles and forwarding
failures are reported directly to the router so must have their own
notification handling.

htlcswitch/switch.go

@@ -898,6 +898,18 @@ func (s *Switch) handleLocalResponse(pkt *htlcPacket) {
 			pkt.inKey(), err)
 		return
 	}
+
+	// Finally, notify on the htlc failure or success that has been handled.
+	key := newHtlcKey(pkt)
+	eventType := getEventType(pkt)
+
+	switch pkt.htlc.(type) {
+	case *lnwire.UpdateFulfillHTLC:
+		s.cfg.HtlcNotifier.NotifySettleEvent(key, eventType)
+
+	case *lnwire.UpdateFailHTLC:
+		s.cfg.HtlcNotifier.NotifyForwardingFailEvent(key, eventType)
+	}
 }
 
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