server+netann+peer: put peer's alias in Update, proper config for link

This commit modifies the netann subsystem to use the peer's alias
for ChannelUpdates where appropriate (i.e. in case we are sending
the alias to the peer). It also modifies the loadActiveChannels
function in the peer package to handle upgrading a channel when the
scid-alias feature bit is turned on.

netann/chan_status_manager.go

@@ -60,7 +60,8 @@ type ChanStatusConfig struct {
 	// ApplyChannelUpdate processes new ChannelUpdates signed by our node by
 	// updating our local routing table and broadcasting the update to our
 	// peers.
-	ApplyChannelUpdate func(*lnwire.ChannelUpdate) error
+	ApplyChannelUpdate func(*lnwire.ChannelUpdate, *wire.OutPoint,
+		bool) error
 
 	// DB stores the set of channels that are to be monitored.
 	DB DB
@@ -621,7 +622,7 @@ func (m *ChanStatusManager) signAndSendNextUpdate(outpoint wire.OutPoint,
 
 	// Retrieve the latest update for this channel. We'll use this
 	// as our starting point to send the new update.
-	chanUpdate, err := m.fetchLastChanUpdateByOutPoint(outpoint)
+	chanUpdate, private, err := m.fetchLastChanUpdateByOutPoint(outpoint)
 	if err != nil {
 		return err
 	}
@@ -634,22 +635,26 @@ func (m *ChanStatusManager) signAndSendNextUpdate(outpoint wire.OutPoint,
 		return err
 	}
 
-	return m.cfg.ApplyChannelUpdate(chanUpdate)
+	return m.cfg.ApplyChannelUpdate(chanUpdate, &outpoint, private)
 }
 
 // fetchLastChanUpdateByOutPoint fetches the latest policy for our direction of
 // a channel, and crafts a new ChannelUpdate with this policy. Returns an error
-// in case our ChannelEdgePolicy is not found in the database.
+// in case our ChannelEdgePolicy is not found in the database. Also returns if
+// the channel is private by checking AuthProof for nil.
 func (m *ChanStatusManager) fetchLastChanUpdateByOutPoint(op wire.OutPoint) (
-	*lnwire.ChannelUpdate, error) {
+	*lnwire.ChannelUpdate, bool, error) {
 
 	// Get the edge info and policies for this channel from the graph.
 	info, edge1, edge2, err := m.cfg.Graph.FetchChannelEdgesByOutpoint(&op)
 	if err != nil {
-		return nil, err
+		return nil, false, err
 	}
 
-	return ExtractChannelUpdate(m.ourPubKeyBytes, info, edge1, edge2)
+	update, err := ExtractChannelUpdate(
+		m.ourPubKeyBytes, info, edge1, edge2,
+	)
+	return update, info.AuthProof == nil, err
 }
 
 // loadInitialChanState determines the initial ChannelState for a particular
@@ -660,7 +665,7 @@ func (m *ChanStatusManager) fetchLastChanUpdateByOutPoint(op wire.OutPoint) (
 func (m *ChanStatusManager) loadInitialChanState(
 	outpoint *wire.OutPoint) (ChannelState, error) {
 
-	lastUpdate, err := m.fetchLastChanUpdateByOutPoint(*outpoint)
+	lastUpdate, _, err := m.fetchLastChanUpdateByOutPoint(*outpoint)
 	if err != nil {
 		return ChannelState{}, err
 	}