multi: implement spec-compliant coop close

channeldb/channel.go

@@ -220,6 +220,10 @@ const (
 	// A tlv type definition used to serialize and deserialize the
 	// confirmed ShortChannelID for a zero-conf channel.
 	realScidType tlv.Type = 4
+
+	// A tlv type definition used to serialize and deserialize the
+	// sentShutdown bool.
+	sentShutdownType tlv.Type = 5
 )
 
 // indexStatus is an enum-like type that describes what state the
@@ -818,6 +822,10 @@ type OpenChannel struct {
 	// default ShortChannelID. This is only set for zero-conf channels.
 	confirmedScid lnwire.ShortChannelID
 
+	// sentShutdown denotes whether or not we've sent the Shutdown message
+	// for this channel.
+	sentShutdown bool
+
 	// TODO(roasbeef): eww
 	Db *ChannelStateDB
 
@@ -1360,6 +1368,51 @@ func (c *OpenChannel) SecondCommitmentPoint() (*btcec.PublicKey, error) {
 	return input.ComputeCommitmentPoint(revocation[:]), nil
 }
 
+// MarkShutdownSent is used to mark that we've sent a Shutdown message for this
+// channel. This is so that we can retransmit Shutdown upon reconnection.
+func (c *OpenChannel) MarkShutdownSent() error {
+	c.Lock()
+	defer c.Unlock()
+
+	if err := kvdb.Update(c.Db.backend, func(tx kvdb.RwTx) error {
+		chanBucket, err := fetchChanBucketRw(
+			tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
+		)
+		if err != nil {
+			return err
+		}
+
+		channel, err := fetchOpenChannel(
+			chanBucket, &c.FundingOutpoint,
+		)
+		if err != nil {
+			return err
+		}
+
+		channel.sentShutdown = true
+
+		return putOpenChannel(chanBucket, channel)
+	}, func() {}); err != nil {
+		return err
+	}
+
+	c.sentShutdown = true
+
+	return nil
+}
+
+// HasSentShutdown returns whether or not we've ever sent Shutdown for this
+// channel. For nodes upgrading to 0.16.0, this will initially be false even if
+// a Shutdown has been sent. This doesn't matter since this function is only
+// used when restarting a ChannelLink and pre-0.16.0 nodes only sent Shutdown
+// after the link was permanently stopped.
+func (c *OpenChannel) HasSentShutdown() bool {
+	c.RLock()
+	defer c.RUnlock()
+
+	return c.sentShutdown
+}
+
 // PersistDeliveryScript is used during the cooperative close flow to persist
 // a script sent in Shutdown when we did not set an upfront shutdown script
 // during the funding flow.
@@ -3673,6 +3726,12 @@ func putChanInfo(chanBucket kvdb.RwBucket, channel *OpenChannel) error {
 	localBalance := uint64(channel.InitialLocalBalance)
 	remoteBalance := uint64(channel.InitialRemoteBalance)
 
+	// Convert sentShutdown to a uint8.
+	var sentShutdownVal uint8
+	if channel.sentShutdown {
+		sentShutdownVal = 1
+	}
+
 	// Create the tlv stream.
 	tlvStream, err := tlv.NewStream(
 		// Write the RevocationKeyLocator as the first entry in a tlv
@@ -3687,6 +3746,9 @@ func putChanInfo(chanBucket kvdb.RwBucket, channel *OpenChannel) error {
 			initialRemoteBalanceType, &remoteBalance,
 		),
 		MakeScidRecord(realScidType, &channel.confirmedScid),
+		tlv.MakePrimitiveRecord(
+			sentShutdownType, &sentShutdownVal,
+		),
 	)
 	if err != nil {
 		return err
@@ -3888,6 +3950,8 @@ func fetchChanInfo(chanBucket kvdb.RBucket, channel *OpenChannel) error {
 	var (
 		localBalance  uint64
 		remoteBalance uint64
+
+		sentShutdownVal uint8
 	)
 
 	// Create the tlv stream.
@@ -3904,6 +3968,9 @@ func fetchChanInfo(chanBucket kvdb.RBucket, channel *OpenChannel) error {
 			initialRemoteBalanceType, &remoteBalance,
 		),
 		MakeScidRecord(realScidType, &channel.confirmedScid),
+		tlv.MakePrimitiveRecord(
+			sentShutdownType, &sentShutdownVal,
+		),
 	)
 	if err != nil {
 		return err
@@ -3917,6 +3984,9 @@ func fetchChanInfo(chanBucket kvdb.RBucket, channel *OpenChannel) error {
 	channel.InitialLocalBalance = lnwire.MilliSatoshi(localBalance)
 	channel.InitialRemoteBalance = lnwire.MilliSatoshi(remoteBalance)
 
+	// Populate the sentShutdown field.
+	channel.sentShutdown = sentShutdownVal == 1
+
 	channel.Packager = NewChannelPackager(channel.ShortChannelID)
 
 	// Finally, read the optional shutdown scripts.