channeldb: added isPending flag and queries

In order to facilitate persistence during the funding process, added
the isPending flag to channels so that when the daemon restarts, we can
properly re-initialize the chain notifier and update the state of
channels that were going through the funding process.

channeldb/channel.go

@@ -67,6 +67,7 @@ var (
 	satSentPrefix        = []byte("ssp")
 	satReceivedPrefix    = []byte("srp")
 	netFeesPrefix        = []byte("ntp")
+	isPendingPrefix      = []byte("pdg")
 
 	// chanIDKey stores the node, and channelID for an active channel.
 	chanIDKey = []byte("cik")
@@ -194,6 +195,10 @@ type OpenChannel struct {
 	// negotiate fees, or close the channel.
 	IsInitiator bool
 
+	// IsPending indicates whether a channel's funding transaction has been
+	// confirmed.
+	IsPending bool
+
 	// FundingOutpoint is the outpoint of the final funding transaction.
 	FundingOutpoint *wire.OutPoint
 
@@ -318,16 +323,18 @@ func (c *OpenChannel) fullSync(tx *bolt.Tx) error {
 	return putOpenChannel(chanBucket, nodeChanBucket, c)
 }
 
-// FullSyncWithAddr is identical to the FullSync function in that it writes the
-// full channel state to disk. Additionally, this function also creates a
-// LinkNode relationship between this newly created channel and an existing of
-// new LinkNode instance. Syncing with this method rather than FullSync is
-// required in order to allow listing all channels in the database globally, or
-// according to the LinkNode they were created with.
+// SyncPending writes the contents of the channel to the database while it's in
+// the pending (waiting for funding confirmation) state. The IsPending flag
+// will be set to true. When the channel's funding transaction is confirmed,
+// the channel should be marked as "open" and the IsPending flag set to false.
+// Note that this function also creates a LinkNode relationship between this
+// newly created channel and a new LinkNode instance. This allows listing all
+// channels in the database globally, or according to the LinkNode they were
+// created with.
 //
 // TODO(roasbeef): addr param should eventually be a lnwire.NetAddress type
 // that includes service bits.
-func (c *OpenChannel) FullSyncWithAddr(addr *net.TCPAddr) error {
+func (c *OpenChannel) SyncPending(addr *net.TCPAddr) error {
 	c.Lock()
 	defer c.Unlock()
 
@@ -732,6 +739,9 @@ func putOpenChannel(openChanBucket *bolt.Bucket, nodeChanBucket *bolt.Bucket,
 	if err := putChanAmountsTransferred(openChanBucket, channel); err != nil {
 		return err
 	}
+	if err := putChanIsPending(openChanBucket, channel); err != nil {
+		return err
+	}
 
 	// Next, write out the fields of the channel update less frequently.
 	if err := putChannelIDs(nodeChanBucket, channel); err != nil {
@@ -816,6 +826,9 @@ func fetchOpenChannel(openChanBucket *bolt.Bucket, nodeChanBucket *bolt.Bucket,
 	if err = fetchChanAmountsTransferred(openChanBucket, channel); err != nil {
 		return nil, fmt.Errorf("unable to read sat transferred: %v", err)
 	}
+	if err = fetchChanIsPending(openChanBucket, channel); err != nil {
+		return nil, err
+	}
 
 	return channel, nil
 }
@@ -843,6 +856,9 @@ func deleteOpenChannel(openChanBucket *bolt.Bucket, nodeChanBucket *bolt.Bucket,
 	if err := deleteChanOurDustLimit(openChanBucket, channelID); err != nil {
 		return err
 	}
+	if err := deleteChanIsPending(openChanBucket, channelID); err != nil {
+		return err
+	}
 
 	// Finally, delete all the fields directly within the node's channel
 	// bucket.
@@ -1159,6 +1175,54 @@ func fetchChanAmountsTransferred(openChanBucket *bolt.Bucket, channel *OpenChann
 	return nil
 }
 
+func putChanIsPending(openChanBucket *bolt.Bucket, channel *OpenChannel) error {
+	scratch := make([]byte, 2)
+
+	var b bytes.Buffer
+	if err := writeOutpoint(&b, channel.ChanID); err != nil {
+		return err
+	}
+
+	keyPrefix := make([]byte, 3+b.Len())
+	copy(keyPrefix[3:], b.Bytes())
+	copy(keyPrefix[:3], isPendingPrefix)
+
+	if channel.IsPending {
+		byteOrder.PutUint16(scratch, uint16(1))
+		return openChanBucket.Put(keyPrefix, scratch)
+	}
+
+	byteOrder.PutUint16(scratch, uint16(0))
+	return openChanBucket.Put(keyPrefix, scratch)
+}
+
+func deleteChanIsPending(openChanBucket *bolt.Bucket, chanID []byte) error {
+	keyPrefix := make([]byte, 3+len(chanID))
+	copy(keyPrefix[3:], chanID)
+	copy(keyPrefix[:3], isPendingPrefix)
+	return openChanBucket.Delete(keyPrefix)
+}
+
+func fetchChanIsPending(openChanBucket *bolt.Bucket, channel *OpenChannel) error {
+	var b bytes.Buffer
+	if err := writeOutpoint(&b, channel.ChanID); err != nil {
+		return err
+	}
+
+	keyPrefix := make([]byte, 3+b.Len())
+	copy(keyPrefix[3:], b.Bytes())
+	copy(keyPrefix[:3], isPendingPrefix)
+
+	isPending := byteOrder.Uint16(openChanBucket.Get(keyPrefix))
+	if isPending == 1 {
+		channel.IsPending = true
+	} else {
+		channel.IsPending = false
+	}
+
+	return nil
+}
+
 func putChannelIDs(nodeChanBucket *bolt.Bucket, channel *OpenChannel) error {
 	// TODO(roasbeef): just pass in chanID everywhere for puts
 	var b bytes.Buffer

channeldb/channel_test.go

@@ -3,6 +3,7 @@ package channeldb
 import (
 	"bytes"
 	"io/ioutil"
+	"net"
 	"os"
 	"reflect"
 	"testing"
@@ -136,6 +137,7 @@ func createTestChannelState(cdb *DB) (*OpenChannel, error) {
 
 	return &OpenChannel{
 		IsInitiator:                true,
+		IsPending:                  true,
 		ChanType:                   SingleFunder,
 		IdentityPub:                pubKey,
 		ChanID:                     id,
@@ -583,3 +585,50 @@ func TestChannelStateTransition(t *testing.T) {
 		t.Fatal("revocation log search should've failed")
 	}
 }
+
+func TestFetchPendingChannels(t *testing.T) {
+	cdb, cleanUp, err := makeTestDB()
+	if err != nil {
+		t.Fatalf("uanble to make test database: %v", err)
+	}
+	defer cleanUp()
+
+	// Create first test channel state
+	state, err := createTestChannelState(cdb)
+	if err != nil {
+		t.Fatalf("unable to create channel state: %v", err)
+	}
+
+	addr := &net.TCPAddr{
+		IP:   net.ParseIP("127.0.0.1"),
+		Port: 18555,
+	}
+
+	if err := state.SyncPending(addr); err != nil {
+		t.Fatalf("unable to save and serialize channel state: %v", err)
+	}
+
+	pendingChannels, err := cdb.FetchPendingChannels()
+	if err != nil {
+		t.Fatalf("unable to list pending channels: %v", err)
+	}
+
+	if len(pendingChannels) != 1 {
+		t.Fatalf("incorrect number of pending channels: expecting %v,"+
+			"got %v", 1, len(pendingChannels))
+	}
+
+	if err := cdb.MarkChannelAsOpen(pendingChannels[0].ChanID); err != nil {
+		t.Fatalf("unable to mark channel as open: %v", err)
+	}
+
+	pendingChannels, err = cdb.FetchPendingChannels()
+	if err != nil {
+		t.Fatalf("unable to list pending channels: %v", err)
+	}
+
+	if len(pendingChannels) != 0 {
+		t.Fatalf("incorrect number of pending channels: expecting %v,"+
+			"got %v", 0, len(pendingChannels))
+	}
+}

channeldb/db.go

@@ -295,9 +295,23 @@ func (d *DB) fetchNodeChannels(openChanBucket,
 }
 
 // FetchAllChannels attempts to retrieve all open channels currently stored
-// within the database. If no active channels exist within the network, then
-// ErrNoActiveChannels is returned.
+// within the database.
 func (d *DB) FetchAllChannels() ([]*OpenChannel, error) {
+	return fetchChannels(d, false)
+}
+
+// FetchPendingChannels will return channels that have completed the process
+// of generating and broadcasting funding transactions, but whose funding
+// transactions have yet to be confirmed on the blockchain.
+func (d *DB) FetchPendingChannels() ([]*OpenChannel, error) {
+	return fetchChannels(d, true)
+}
+
+// fetchChannels attempts to retrieve channels currently stored in the
+// database. The pendingOnly parameter determines whether only pending
+// channels will be returned. If no active channels exist within the network,
+// then ErrNoActiveChannels is returned.
+func fetchChannels(d *DB, pendingOnly bool) ([]*OpenChannel, error) {
 	var channels []*OpenChannel
 
 	err := d.View(func(tx *bolt.Tx) error {
@@ -330,8 +344,15 @@ func (d *DB) FetchAllChannels() ([]*OpenChannel, error) {
 				return fmt.Errorf("unable to read channel for "+
 					"node_key=%x: %v", k, err)
 			}
-
-			channels = append(channels, nodeChannels...)
+			if pendingOnly {
+				for _, channel := range nodeChannels {
+					if channel.IsPending == true {
+						channels = append(channels, channel)
+					}
+				}
+			} else {
+				channels = append(channels, nodeChannels...)
+			}
 			return nil
 		})
 	})
@@ -339,6 +360,38 @@ func (d *DB) FetchAllChannels() ([]*OpenChannel, error) {
 	return channels, err
 }
 
+// MarkChannelAsOpen records the finalization of the funding process and marks
+// a channel as available for use.
+func (d *DB) MarkChannelAsOpen(outpoint *wire.OutPoint) error {
+	err := d.Update(func(tx *bolt.Tx) error {
+		openChanBucket := tx.Bucket(openChannelBucket)
+		if openChanBucket == nil {
+			return ErrNoActiveChannels
+		}
+
+		// Generate the database key, which will consist of the IsPending
+		// prefix followed by the channel's outpoint.
+		var b bytes.Buffer
+		if err := writeOutpoint(&b, outpoint); err != nil {
+			return err
+		}
+		keyPrefix := make([]byte, 3+b.Len())
+		copy(keyPrefix[3:], b.Bytes())
+		copy(keyPrefix[:3], isPendingPrefix)
+
+		// For the database value, store a zero, since the channel is no
+		// longer pending.
+		scratch := make([]byte, 2)
+		byteOrder.PutUint16(scratch, uint16(0))
+		return openChanBucket.Put(keyPrefix, scratch)
+	})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 // syncVersions function is used for safe db version synchronization. It applies
 // migration functions to the current database and recovers the previous
 // state of db if at least one error/panic appeared during migration.

fundingmanager.go

@@ -241,17 +241,22 @@ func (f *fundingManager) Stop() error {
 
 type numPendingReq struct {
 	resp chan uint32
+	err  chan error
 }
 
 // NumPendingChannels returns the number of pending channels currently
 // progressing through the reservation workflow.
-func (f *fundingManager) NumPendingChannels() uint32 {
-	resp := make(chan uint32, 1)
+func (f *fundingManager) NumPendingChannels() (uint32, error) {
+	respChan := make(chan uint32, 1)
+	errChan := make(chan error)
 
-	req := &numPendingReq{resp}
+	req := &numPendingReq{
+		resp: respChan,
+		err:  errChan,
+	}
 	f.queries <- req
 
-	return <-resp
+	return <-respChan, <-errChan
 }
 
 type pendingChannel struct {
@@ -264,17 +269,22 @@ type pendingChannel struct {
 
 type pendingChansReq struct {
 	resp chan []*pendingChannel
+	err  chan error
 }
 
 // PendingChannels returns a slice describing all the channels which are
 // currently pending at the last state of the funding workflow.
-func (f *fundingManager) PendingChannels() []*pendingChannel {
-	resp := make(chan []*pendingChannel, 1)
+func (f *fundingManager) PendingChannels() ([]*pendingChannel, error) {
+	respChan := make(chan []*pendingChannel, 1)
+	errChan := make(chan error)
 
-	req := &pendingChansReq{resp}
+	req := &pendingChansReq{
+		resp: respChan,
+		err:  errChan,
+	}
 	f.queries <- req
 
-	return <-resp
+	return <-respChan, <-errChan
 }
 
 // reservationCoordinator is the primary goroutine tasked with progressing the
@@ -322,7 +332,18 @@ func (f *fundingManager) handleNumPending(msg *numPendingReq) {
 	for _, peerChannels := range f.activeReservations {
 		numPending += uint32(len(peerChannels))
 	}
+
+	dbPendingChannels, err := f.cfg.Wallet.ChannelDB.FetchPendingChannels()
+	if err != nil {
+		close(msg.resp)
+		msg.err <- err
+		return
+	}
+
+	numPending = numPending + uint32(len(dbPendingChannels))
+
 	msg.resp <- numPending
+	msg.err <- nil
 }
 
 // handlePendingChannels responds to a request for details concerning all
@@ -346,7 +367,28 @@ func (f *fundingManager) handlePendingChannels(msg *pendingChansReq) {
 			pendingChannels = append(pendingChannels, pendingChan)
 		}
 	}
+
+	dbPendingChannels, err := f.cfg.Wallet.ChannelDB.FetchPendingChannels()
+	if err != nil {
+		msg.resp <- nil
+		msg.err <- err
+		return
+	}
+
+	for _, dbPendingChan := range dbPendingChannels {
+		pendingChan := &pendingChannel{
+			identityPub:   dbPendingChan.IdentityPub,
+			channelPoint:  dbPendingChan.ChanID,
+			capacity:      dbPendingChan.Capacity,
+			localBalance:  dbPendingChan.OurBalance,
+			remoteBalance: dbPendingChan.TheirBalance,
+		}
+
+		pendingChannels = append(pendingChannels, pendingChan)
+	}
+
 	msg.resp <- pendingChannels
+	msg.err <- nil
 }
 
 // processFundingRequest sends a message to the fundingManager allowing it to

lnwallet/reservation.go

@@ -204,6 +204,7 @@ func NewChannelReservation(capacity, fundingAmt btcutil.Amount, minFeeRate btcut
 		partialState: &channeldb.OpenChannel{
 			Capacity:     capacity,
 			IsInitiator:  initiator,
+			IsPending:    true,
 			ChanType:     chanType,
 			OurBalance:   ourBalance,
 			TheirBalance: theirBalance,

lnwallet/wallet.go

@@ -1066,7 +1066,7 @@ func (l *LightningWallet) handleFundingCounterPartySigs(msg *addCounterPartySigs
 	// which will be used for the lifetime of this channel.
 	// TODO(roasbeef): revisit faul-tolerance of this flow
 	nodeAddr := res.nodeAddr
-	if err := res.partialState.FullSyncWithAddr(nodeAddr); err != nil {
+	if err := res.partialState.SyncPending(nodeAddr); err != nil {
 		msg.err <- err
 		return
 	}
@@ -1220,7 +1220,7 @@ func (l *LightningWallet) handleChannelOpen(req *channelOpenMsg) {
 
 	// Add the complete funding transaction to the DB, in it's open bucket
 	// which will be used for the lifetime of this channel.
-	if err := res.partialState.FullSyncWithAddr(res.nodeAddr); err != nil {
+	if err := res.partialState.SyncPending(res.nodeAddr); err != nil {
 		req.err <- err
 		res.chanOpen <- nil
 		return

rpcserver.go

@@ -631,7 +631,11 @@ func (r *rpcServer) GetInfo(ctx context.Context,
 		activeChannels += uint32(len(serverPeer.ChannelSnapshots()))
 	}
 
-	pendingChannels := r.server.fundingMgr.NumPendingChannels()
+	pendingChannels, err := r.server.fundingMgr.NumPendingChannels()
+	if err != nil {
+		return nil, err
+	}
+
 	idPub := r.server.identityPriv.PubKey().SerializeCompressed()
 
 	bestHash, bestHeight, err := r.server.bio.GetBestBlock()
@@ -760,7 +764,10 @@ func (r *rpcServer) PendingChannels(ctx context.Context,
 
 	var pendingChannels []*lnrpc.PendingChannelResponse_PendingChannel
 	if includeOpen {
-		pendingOpenChans := r.server.fundingMgr.PendingChannels()
+		pendingOpenChans, err := r.server.fundingMgr.PendingChannels()
+		if err != nil {
+			return nil, err
+		}
 		for _, pendingOpen := range pendingOpenChans {
 			channelPointStr := "<non initialized yet>"
 			if pendingOpen.channelPoint != nil {