funding: notify aux negotiator on ChannelReady

We notify the aux channel negotiator that an established channel is now
ready to use. This helps correlate the peer custom features with the
channel identifier of the ready channel.

Author: GeorgeTsagk

funding/manager.go

@@ -569,6 +569,11 @@ type Config struct {
 	// AuxResolver is an optional interface that can be used to modify the
 	// way contracts are resolved.
 	AuxResolver fn.Option[lnwallet.AuxContractResolver]
+
+	// AuxChannelNegotiator is an optional interface that allows aux channel
+	// implementations to inject and process feature bits during init and
+	// channel_reestablish messages.
+	AuxChannelNegotiator fn.Option[lnwallet.AuxChannelNegotiator]
 }
 
 // Manager acts as an orchestrator/bridge between the wallet's
@@ -3914,6 +3919,14 @@ func (f *Manager) handleChannelReady(peer lnpeer.Peer, //nolint:funlen
 
 	defer f.wg.Done()
 
+	// Notify the aux hook that the specified peer just established a
+	// channel with us, identified by the given channel ID.
+	f.cfg.AuxChannelNegotiator.WhenSome(
+		func(acn lnwallet.AuxChannelNegotiator) {
+			acn.ProcessChannelReady(msg.ChanID, peer.PubKey())
+		},
+	)
+
 	// If we are in development mode, we'll wait for specified duration
 	// before processing the channel ready message.
 	if f.cfg.Dev != nil {

server.go

@@ -1627,6 +1627,7 @@ func newServer(ctx context.Context, cfg *Config, listenAddrs []net.Addr,
 		AuxFundingController: implCfg.AuxFundingController,
 		AuxSigner:            implCfg.AuxSigner,
 		AuxResolver:          implCfg.AuxContractResolver,
+		AuxChannelNegotiator: implCfg.AuxChannelNegotiator,
 	})
 	if err != nil {
 		return nil, err