htlcswitch/interface: add TowerClient iface

htlcswitch/interfaces.go

@@ -6,6 +6,7 @@ import (
 	"github.com/lightningnetwork/lnd/invoices"
 	"github.com/lightningnetwork/lnd/lnpeer"
 	"github.com/lightningnetwork/lnd/lntypes"
+	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -159,3 +160,20 @@ type ForwardingLog interface {
 	// visualizations, etc.
 	AddForwardingEvents([]channeldb.ForwardingEvent) error
 }
+
+// TowerClient is the primary interface used by the daemon to backup pre-signed
+// justice transactions to watchtowers.
+type TowerClient interface {
+	// RegisterChannel persistently initializes any channel-dependent
+	// parameters within the client. This should be called during link
+	// startup to ensure that the client is able to support the link during
+	// operation.
+	RegisterChannel(lnwire.ChannelID) error
+
+	// BackupState initiates a request to back up a particular revoked
+	// state. If the method returns nil, the backup is guaranteed to be
+	// successful unless the tower is unavailable and client is force quit,
+	// or the justice transaction would create dust outputs when trying to
+	// abide by the negotiated policy.
+	BackupState(*lnwire.ChannelID, *lnwallet.BreachRetribution) error
+}