chanbackup: add SCB support for new anchor commitments

chanbackup/backup.go

@@ -62,12 +62,6 @@ func FetchBackupForChan(chanPoint wire.OutPoint,
 		return nil, fmt.Errorf("unable to find target channel")
 	}
 
-	// TODO(halseth): support chan backups for anchor types.
-	if targetChan.ChanType.HasAnchors() {
-		return nil, fmt.Errorf("channel type does not support " +
-			"backups yet")
-	}
-
 	// Once we have the target channel, we can assemble the backup using
 	// the source to obtain any extra information that we may need.
 	staticChanBackup, err := assembleChanBackup(chanSource, targetChan)
@@ -93,11 +87,6 @@ func FetchStaticChanBackups(chanSource LiveChannelSource) ([]Single, error) {
 	// channel.
 	staticChanBackups := make([]Single, 0, len(openChans))
 	for _, openChan := range openChans {
-		// TODO(halseth): support chan backups for anchor types.
-		if openChan.ChanType.HasAnchors() {
-			continue
-		}
-
 		chanBackup, err := assembleChanBackup(chanSource, openChan)
 		if err != nil {
 			return nil, err

chanbackup/pubsub.go

@@ -213,12 +213,6 @@ func (s *SubSwapper) backupUpdater() {
 			// For all new open channels, we'll create a new SCB
 			// given the required information.
 			for _, newChan := range chanUpdate.NewChans {
-				// TODO(halseth): support chan backups for
-				// anchor types.
-				if newChan.ChanType.HasAnchors() {
-					continue
-				}
-
 				log.Debugf("Adding channel %v to backup state",
 					newChan.FundingOutpoint)
 

chanbackup/single.go

@@ -31,6 +31,11 @@ const (
 	// implicitly denotes that this channel uses the new tweakless commit
 	// format.
 	TweaklessCommitVersion = 1
+
+	// AnchorsCommitVersion is the third SCB version. This version
+	// implicitly denotes that this channel uses the new anchor commitment
+	// format.
+	AnchorsCommitVersion = 2
 )
 
 // Single is a static description of an existing channel that can be used for
@@ -157,9 +162,14 @@ func NewSingle(channel *channeldb.OpenChannel,
 		},
 	}
 
-	if channel.ChanType.IsTweakless() {
+	switch {
+	case channel.ChanType.HasAnchors():
+		single.Version = AnchorsCommitVersion
+
+	case channel.ChanType.IsTweakless():
 		single.Version = TweaklessCommitVersion
-	} else {
+
+	default:
 		single.Version = DefaultSingleVersion
 	}
 
@@ -174,6 +184,7 @@ func (s *Single) Serialize(w io.Writer) error {
 	switch s.Version {
 	case DefaultSingleVersion:
 	case TweaklessCommitVersion:
+	case AnchorsCommitVersion:
 	default:
 		return fmt.Errorf("unable to serialize w/ unknown "+
 			"version: %v", s.Version)
@@ -332,6 +343,7 @@ func (s *Single) Deserialize(r io.Reader) error {
 	switch s.Version {
 	case DefaultSingleVersion:
 	case TweaklessCommitVersion:
+	case AnchorsCommitVersion:
 	default:
 		return fmt.Errorf("unable to de-serialize w/ unknown "+
 			"version: %v", s.Version)

chanbackup/single_test.go

@@ -229,12 +229,20 @@ func TestSinglePackUnpack(t *testing.T) {
 			valid:   true,
 		},
 
-		// The new tweakless version, should pack/unpack with no problem.
+		// The new tweakless version, should pack/unpack with no
+		// problem.
 		{
 			version: TweaklessCommitVersion,
 			valid:   true,
 		},
 
+		// The new anchor version, should pack/unpack with no
+		// problem.
+		{
+			version: AnchorsCommitVersion,
+			valid:   true,
+		},
+
 		// A non-default version, atm this should result in a failure.
 		{
 			version: 99,

chanrestore.go

@@ -106,10 +106,17 @@ func (c *chanDBRestorer) openChannelShell(backup chanbackup.Single) (
 	case chanbackup.TweaklessCommitVersion:
 		chanType = channeldb.SingleFunderTweaklessBit
 
+	case chanbackup.AnchorsCommitVersion:
+		chanType = channeldb.AnchorOutputsBit
+		chanType |= channeldb.SingleFunderTweaklessBit
+
 	default:
 		return nil, fmt.Errorf("unknown Single version: %v", err)
 	}
 
+	ltndLog.Infof("SCB Recovery: created channel shell for ChannelPoint(%v), "+
+		"chan_type=%v", backup.FundingOutpoint, chanType)
+
 	chanShell := channeldb.ChannelShell{
 		NodeAddrs: backup.Addresses,
 		Chan: &channeldb.OpenChannel{