multi: link notifies subscribers of ActiveLinkEvent, rpc ignores

htlcswitch/link.go

@@ -265,6 +265,10 @@ type ChannelLinkConfig struct {
 	// initiator of the channel.
 	MaxFeeAllocation float64
 
+	// NotifyActiveLink allows the link to tell the ChannelNotifier when a
+	// link is first started.
+	NotifyActiveLink func(wire.OutPoint)
+
 	// NotifyActiveChannel allows the link to tell the ChannelNotifier when
 	// channels becomes active.
 	NotifyActiveChannel func(wire.OutPoint)
@@ -870,6 +874,10 @@ func (l *channelLink) htlcManager() {
 
 	l.log.Infof("HTLC manager started, bandwidth=%v", l.Bandwidth())
 
+	// Notify any clients that the link is now in the switch via an
+	// ActiveLinkEvent.
+	l.cfg.NotifyActiveLink(*l.ChannelPoint())
+
 	// TODO(roasbeef): need to call wipe chan whenever D/C?
 
 	// If this isn't the first time that this channel link has been

htlcswitch/link_test.go

@@ -1748,6 +1748,7 @@ func newSingleLinkTestHarness(chanAmt, chanReserve btcutil.Amount) (
 		MaxFeeUpdateTimeout:   40 * time.Minute,
 		MaxOutgoingCltvExpiry: DefaultMaxOutgoingCltvExpiry,
 		MaxFeeAllocation:      DefaultMaxLinkFeeAllocation,
+		NotifyActiveLink:      func(wire.OutPoint) {},
 		NotifyActiveChannel:   func(wire.OutPoint) {},
 		NotifyInactiveChannel: func(wire.OutPoint) {},
 		HtlcNotifier:          aliceSwitch.cfg.HtlcNotifier,
@@ -4474,6 +4475,7 @@ func (h *persistentLinkHarness) restartLink(
 		HodlMask:              hodl.MaskFromFlags(hodlFlags...),
 		MaxOutgoingCltvExpiry: DefaultMaxOutgoingCltvExpiry,
 		MaxFeeAllocation:      DefaultMaxLinkFeeAllocation,
+		NotifyActiveLink:      func(wire.OutPoint) {},
 		NotifyActiveChannel:   func(wire.OutPoint) {},
 		NotifyInactiveChannel: func(wire.OutPoint) {},
 		HtlcNotifier:          aliceSwitch.cfg.HtlcNotifier,

htlcswitch/test_utils.go

@@ -1173,6 +1173,7 @@ func (h *hopNetwork) createChannelLink(server, peer *mockServer,
 			OutgoingCltvRejectDelta: 3,
 			MaxOutgoingCltvExpiry:   DefaultMaxOutgoingCltvExpiry,
 			MaxFeeAllocation:        DefaultMaxLinkFeeAllocation,
+			NotifyActiveLink:        func(wire.OutPoint) {},
 			NotifyActiveChannel:     func(wire.OutPoint) {},
 			NotifyInactiveChannel:   func(wire.OutPoint) {},
 			HtlcNotifier:            server.htlcSwitch.cfg.HtlcNotifier,

peer.go

@@ -21,6 +21,7 @@ import (
 	"github.com/lightningnetwork/lnd/buffer"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/channelnotifier"
 	"github.com/lightningnetwork/lnd/contractcourt"
 	"github.com/lightningnetwork/lnd/feature"
 	"github.com/lightningnetwork/lnd/htlcswitch"
@@ -649,6 +650,7 @@ func (p *peer) addLink(chanPoint *wire.OutPoint,
 		TowerClient:             p.server.towerClient,
 		MaxOutgoingCltvExpiry:   cfg.MaxOutgoingCltvExpiry,
 		MaxFeeAllocation:        cfg.MaxChannelFeeAllocation,
+		NotifyActiveLink:        p.server.channelNotifier.NotifyActiveLinkEvent,
 		NotifyActiveChannel:     p.server.channelNotifier.NotifyActiveChannelEvent,
 		NotifyInactiveChannel:   p.server.channelNotifier.NotifyInactiveChannelEvent,
 		HtlcNotifier:            p.server.htlcNotifier,

rpcserver.go

@@ -3522,6 +3522,11 @@ func (r *rpcServer) SubscribeChannelEvents(req *lnrpc.ChannelEventSubscription,
 					},
 				}
 
+			// Completely ignore ActiveLinkEvent as this is explicitly not
+			// exposed to the RPC.
+			case channelnotifier.ActiveLinkEvent:
+				continue
+
 			default:
 				return fmt.Errorf("unexpected channel event update: %v", event)
 			}
@@ -5896,6 +5901,8 @@ func (r *rpcServer) SubscribeChannelBackups(req *lnrpc.ChannelBackupSubscription
 				continue
 			case channelnotifier.InactiveChannelEvent:
 				continue
+			case channelnotifier.ActiveLinkEvent:
+				continue
 			}
 
 			// Now that we know the channel state has changed,