Merge pull request #2923 from Roasbeef/scb-peer-fixes

multi: peer related SCB fixes

chanrestore.go

@@ -156,6 +156,14 @@ var _ chanbackup.ChannelRestorer = (*chanDBRestorer)(nil)
 //
 // NOTE: Part of the chanbackup.PeerConnector interface.
 func (s *server) ConnectPeer(nodePub *btcec.PublicKey, addrs []net.Addr) error {
+	// Before we connect to the remote peer, we'll remove any connections
+	// to ensure the new connection is created after this new link/channel
+	// is known.
+	if err := s.DisconnectPeer(nodePub); err != nil {
+		ltndLog.Infof("Peer(%v) is already connected, proceeding "+
+			"with chan restore", nodePub.SerializeCompressed())
+	}
+
 	// For each of the known addresses, we'll attempt to launch a
 	// persistent connection to the (pub, addr) pair. In the event that any
 	// of them connect, all the other stale requests will be cancelled.
@@ -171,7 +179,16 @@ func (s *server) ConnectPeer(nodePub *btcec.PublicKey, addrs []net.Addr) error {
 		// Attempt to connect to the peer using this full address. If
 		// we're unable to connect to them, then we'll try the next
 		// address in place of it.
-		if err := s.ConnectToPeer(netAddr, true); err != nil {
+		err := s.ConnectToPeer(netAddr, true)
+
+		// If we're already connected to this peer, then we don't
+		// consider this an error, so we'll exit here.
+		if _, ok := err.(*errPeerAlreadyConnected); ok {
+			return nil
+
+		} else if err != nil {
+			// Otherwise, something else happened, so we'll try the
+			// next address.
 			ltndLog.Errorf("unable to connect to %v to "+
 				"complete SCB restore: %v", netAddr, err)
 			continue

htlcswitch/link.go

@@ -574,7 +574,7 @@ func (l *channelLink) syncChanStates() error {
 		return fmt.Errorf("unable to generate chan sync message for "+
 			"ChannelPoint(%v)", l.channel.ChannelPoint())
 	}
-	if err := l.cfg.Peer.SendMessage(false, localChanSyncMsg); err != nil {
+	if err := l.cfg.Peer.SendMessage(true, localChanSyncMsg); err != nil {
 		return fmt.Errorf("Unable to send chan sync message for "+
 			"ChannelPoint(%v)", l.channel.ChannelPoint())
 	}

server.go

@@ -89,6 +89,19 @@ var (
 	validColorRegexp = regexp.MustCompile("^#[A-Fa-f0-9]{6}$")
 )
 
+// errPeerAlreadyConnected is an error returned by the server when we're
+// commanded to connect to a peer, but they're already connected.
+type errPeerAlreadyConnected struct {
+	peer *peer
+}
+
+// Error returns the human readable version of this error type.
+//
+// NOTE: Part of the error interface.
+func (e *errPeerAlreadyConnected) Error() string {
+	return fmt.Sprintf("already connected to peer: %v", e.peer)
+}
+
 // server is the main server of the Lightning Network Daemon. The server houses
 // global state pertaining to the wallet, database, and the rpcserver.
 // Additionally, the server is also used as a central messaging bus to interact
@@ -2875,7 +2888,7 @@ func (s *server) ConnectToPeer(addr *lnwire.NetAddress, perm bool) error {
 	peer, err := s.findPeerByPubStr(targetPub)
 	if err == nil {
 		s.mu.Unlock()
-		return fmt.Errorf("already connected to peer: %v", peer)
+		return &errPeerAlreadyConnected{peer: peer}
 	}
 
 	// Peer was not found, continue to pursue connection with peer.