rpcserver+invoicesrpc: alias-aware AddInvoice,AddHoldInvoice rpc

AddInvoice,AddHoldInvoice now issue invoices that include our
peer's aliases. Some extra sanity checks are included to ensure we
don't leak our confirmed SCID for a private channel.

lnrpc/invoicesrpc/addinvoice.go

@@ -72,6 +72,10 @@ type AddInvoiceConfig struct {
 	// GenAmpInvoiceFeatures returns a feature containing feature bits that
 	// should be advertised on freshly generated AMP invoices.
 	GenAmpInvoiceFeatures func() *lnwire.FeatureVector
+
+	// GetAlias allows the peer's alias SCID to be retrieved for private
+	// option_scid_alias channels.
+	GetAlias func(lnwire.ChannelID) (lnwire.ShortChannelID, error)
 }
 
 // AddInvoiceData contains the required data to create a new invoice.
@@ -387,9 +391,27 @@ func AddInvoice(ctx context.Context, cfg *AddInvoiceConfig,
 					continue
 				}
 
+				// If this is a zero-conf channel, check if the
+				// confirmed SCID was used in forcedHints.
+				realScid := c.ZeroConfRealScid().ToUint64()
+				if c.IsZeroConf() {
+					if _, ok := forcedHints[realScid]; ok {
+						continue
+					}
+				}
+
 				chanID := lnwire.NewChanIDFromOutPoint(
 					&c.FundingOutpoint,
 				)
+
+				// Check whether the the peer's alias was
+				// provided in forcedHints.
+				peerAlias, _ := cfg.GetAlias(chanID)
+				peerScid := peerAlias.ToUint64()
+				if _, ok := forcedHints[peerScid]; ok {
+					continue
+				}
+
 				isActive := cfg.IsChannelActive(chanID)
 
 				hopHintInfo := newHopHintInfo(c, isActive)
@@ -529,10 +551,17 @@ func chanCanBeHopHint(channel *HopHintInfo, cfg *SelectHopHintsCfg) (
 	// Fetch the policies for each end of the channel.
 	info, p1, p2, err := cfg.FetchChannelEdgesByID(channel.ShortChannelID)
 	if err != nil {
-		log.Errorf("Unable to fetch the routing "+
+		// In the case of zero-conf channels, it may be the case that
-			"policies for the edges of the channel "+
+		// the alias SCID was deleted from the graph, and replaced by
-			"%v: %v", channel.ShortChannelID, err)
+		// the confirmed SCID. Check the Graph for the confirmed SCID.
-		return nil, false
+		confirmedScid := channel.ConfirmedScidZC
+		info, p1, p2, err = cfg.FetchChannelEdgesByID(confirmedScid)
+		if err != nil {
+			log.Errorf("Unable to fetch the routing policies for "+
+				"the edges of the channel %v: %v",
+				channel.ShortChannelID, err)
+			return nil, false
+		}
 	}
 
 	// Now, we'll need to determine which is the correct policy for HTLCs
@@ -550,7 +579,8 @@ func chanCanBeHopHint(channel *HopHintInfo, cfg *SelectHopHintsCfg) (
 // addHopHint creates a hop hint out of the passed channel and channel policy.
 // The new hop hint is appended to the passed slice.
 func addHopHint(hopHints *[][]zpay32.HopHint,
-	channel *HopHintInfo, chanPolicy *channeldb.ChannelEdgePolicy) {
+	channel *HopHintInfo, chanPolicy *channeldb.ChannelEdgePolicy,
+	aliasScid lnwire.ShortChannelID) {
 
 	hopHint := zpay32.HopHint{
 		NodeID:      channel.RemotePubkey,
@@ -562,6 +592,11 @@ func addHopHint(hopHints *[][]zpay32.HopHint,
 		CLTVExpiryDelta: chanPolicy.TimeLockDelta,
 	}
 
+	var defaultScid lnwire.ShortChannelID
+	if aliasScid != defaultScid {
+		hopHint.ChannelID = aliasScid.ToUint64()
+	}
+
 	*hopHints = append(*hopHints, []zpay32.HopHint{hopHint})
 }
 
@@ -587,18 +622,28 @@ type HopHintInfo struct {
 
 	// ShortChannelID is the short channel ID of the channel.
 	ShortChannelID uint64
+
+	// ConfirmedScidZC is the confirmed SCID of a zero-conf channel. This
+	// may be used for looking up a channel in the graph.
+	ConfirmedScidZC uint64
+
+	// ScidAliasFeature denotes whether the channel has negotiated the
+	// option-scid-alias feature bit.
+	ScidAliasFeature bool
 }
 
 func newHopHintInfo(c *channeldb.OpenChannel, isActive bool) *HopHintInfo {
 	isPublic := c.ChannelFlags&lnwire.FFAnnounceChannel != 0
 
 	return &HopHintInfo{
-		IsPublic:        isPublic,
+		IsPublic:         isPublic,
-		IsActive:        isActive,
+		IsActive:         isActive,
-		FundingOutpoint: c.FundingOutpoint,
+		FundingOutpoint:  c.FundingOutpoint,
-		RemotePubkey:    c.IdentityPub,
+		RemotePubkey:     c.IdentityPub,
-		RemoteBalance:   c.LocalCommitment.RemoteBalance,
+		RemoteBalance:    c.LocalCommitment.RemoteBalance,
-		ShortChannelID:  c.ShortChannelID.ToUint64(),
+		ShortChannelID:   c.ShortChannelID.ToUint64(),
+		ConfirmedScidZC:  c.ZeroConfRealScid().ToUint64(),
+		ScidAliasFeature: c.ChanType.HasScidAliasFeature(),
 	}
 }
 
@@ -615,12 +660,17 @@ type SelectHopHintsCfg struct {
 	FetchChannelEdgesByID func(chanID uint64) (*channeldb.ChannelEdgeInfo,
 		*channeldb.ChannelEdgePolicy, *channeldb.ChannelEdgePolicy,
 		error)
+
+	// GetAlias allows the peer's alias SCID to be retrieved for private
+	// option_scid_alias channels.
+	GetAlias func(lnwire.ChannelID) (lnwire.ShortChannelID, error)
 }
 
 func newSelectHopHintsCfg(invoicesCfg *AddInvoiceConfig) *SelectHopHintsCfg {
 	return &SelectHopHintsCfg{
 		IsPublicNode:          invoicesCfg.Graph.IsPublicNode,
 		FetchChannelEdgesByID: invoicesCfg.Graph.FetchChannelEdgesByID,
+		GetAlias:              invoicesCfg.GetAlias,
 	}
 }
 
@@ -693,9 +743,26 @@ func SelectHopHints(amtMSat lnwire.MilliSatoshi, cfg *SelectHopHintsCfg,
 			continue
 		}
 
+		// Lookup and see if there is an alias SCID that exists.
+		chanID := lnwire.NewChanIDFromOutPoint(
+			&channel.FundingOutpoint,
+		)
+		alias, _ := cfg.GetAlias(chanID)
+
+		// If this is a channel where the option-scid-alias feature bit
+		// was negotiated and the alias is not yet assigned, we cannot
+		// issue an invoice. Doing so might expose the confirmed SCID
+		// of a private channel.
+		if channel.ScidAliasFeature {
+			var defaultScid lnwire.ShortChannelID
+			if alias == defaultScid {
+				continue
+			}
+		}
+
 		// Now that we now this channel use usable, add it as a hop
 		// hint and the indexes we'll use later.
-		addHopHint(&hopHints, channel, edgePolicy)
+		addHopHint(&hopHints, channel, edgePolicy, alias)
 
 		hopHintChans[channel.FundingOutpoint] = struct{}{}
 		totalHintBandwidth += channel.RemoteBalance
@@ -733,9 +800,26 @@ func SelectHopHints(amtMSat lnwire.MilliSatoshi, cfg *SelectHopHintsCfg,
 			continue
 		}
 
+		// Lookup and see if there's an alias SCID that exists.
+		chanID := lnwire.NewChanIDFromOutPoint(
+			&channel.FundingOutpoint,
+		)
+		alias, _ := cfg.GetAlias(chanID)
+
+		// If this is a channel where the option-scid-alias feature bit
+		// was negotiated and the alias is not yet assigned, we cannot
+		// issue an invoice. Doing so might expose the confirmed SCID
+		// of a private channel.
+		if channel.ScidAliasFeature {
+			var defaultScid lnwire.ShortChannelID
+			if alias == defaultScid {
+				continue
+			}
+		}
+
 		// Include the route hint in our set of options that will be
 		// used when creating the invoice.
-		addHopHint(&hopHints, channel, remotePolicy)
+		addHopHint(&hopHints, channel, remotePolicy, alias)
 
 		// As we've just added a new hop hint, we'll accumulate it's
 		// available balance now to update our tally.

lnrpc/invoicesrpc/addinvoice_test.go

@@ -274,11 +274,11 @@ func TestSelectHopHints(t *testing.T) {
 				// hop hint.
 				h.Mock.On(
 					"FetchChannelEdgesByID",
-					private1ShortID,
+					mock.Anything,
 				).Return(
 					nil, nil, nil,
 					errors.New("no edge"),
-				)
+				).Times(4)
 			},
 			amount: 100,
 			channels: []*HopHintInfo{
@@ -536,6 +536,10 @@ func TestSelectHopHints(t *testing.T) {
 		},
 	}
 
+	getAlias := func(lnwire.ChannelID) (lnwire.ShortChannelID, error) {
+		return lnwire.ShortChannelID{}, nil
+	}
+
 	for _, test := range tests {
 		test := test
 
@@ -548,6 +552,7 @@ func TestSelectHopHints(t *testing.T) {
 			cfg := &SelectHopHintsCfg{
 				IsPublicNode:          mock.IsPublicNode,
 				FetchChannelEdgesByID: mock.FetchChannelEdgesByID,
+				GetAlias:              getAlias,
 			}
 
 			hints := SelectHopHints(

lnrpc/invoicesrpc/config_active.go

@@ -60,4 +60,8 @@ type Config struct {
 	// GenAmpInvoiceFeatures returns a feature containing feature bits that
 	// should be advertised on freshly generated AMP invoices.
 	GenAmpInvoiceFeatures func() *lnwire.FeatureVector
+
+	// GetAlias returns the peer's alias SCID if it exists given the
+	// 32-byte ChannelID.
+	GetAlias func(lnwire.ChannelID) (lnwire.ShortChannelID, error)
 }

lnrpc/invoicesrpc/invoices_server.go

@@ -331,6 +331,7 @@ func (s *Server) AddHoldInvoice(ctx context.Context,
 		Graph:                 s.cfg.GraphDB,
 		GenInvoiceFeatures:    s.cfg.GenInvoiceFeatures,
 		GenAmpInvoiceFeatures: s.cfg.GenAmpInvoiceFeatures,
+		GetAlias:              s.cfg.GetAlias,
 	}
 
 	hash, err := lntypes.MakeHash(invoice.Hash)

rpcserver.go

@@ -756,6 +756,7 @@ func (r *rpcServer) addDeps(s *server, macService *macaroons.Service,
 		r.cfg.net.ResolveTCPAddr, genInvoiceFeatures,
 		genAmpInvoiceFeatures, getNodeAnnouncement,
 		s.updateAndBrodcastSelfNode, parseAddr, rpcsLog,
+		s.aliasMgr.GetPeerAlias,
 	)
 	if err != nil {
 		return err
@@ -3039,7 +3040,7 @@ func (r *rpcServer) SubscribePeerEvents(req *lnrpc.PeerEventSubscription,
 // confirmed unspent outputs and all unconfirmed unspent outputs under control
 // by the wallet. This method can be modified by having the request specify
 // only witness outputs should be factored into the final output sum.
-// TODO(roasbeef): add async hooks into wallet balance changes
+// TODO(roasbeef): add async hooks into wallet balance changes.
 func (r *rpcServer) WalletBalance(ctx context.Context,
 	in *lnrpc.WalletBalanceRequest) (*lnrpc.WalletBalanceResponse, error) {
 
@@ -5260,6 +5261,7 @@ func (r *rpcServer) AddInvoice(ctx context.Context,
 		GenAmpInvoiceFeatures: func() *lnwire.FeatureVector {
 			return r.server.featureMgr.Get(feature.SetInvoiceAmp)
 		},
+		GetAlias: r.server.aliasMgr.GetPeerAlias,
 	}
 
 	value, err := lnrpc.UnmarshallAmt(invoice.Value, invoice.ValueMsat)

subrpcserver_config.go

@@ -121,7 +121,8 @@ func (s *subRPCServerConfigs) PopulateDependencies(cfg *Config,
 	getNodeAnnouncement func() (lnwire.NodeAnnouncement, error),
 	updateNodeAnnouncement func(modifiers ...netann.NodeAnnModifier) error,
 	parseAddr func(addr string) (net.Addr, error),
-	rpcLogger btclog.Logger) error {
+	rpcLogger btclog.Logger,
+	getAlias func(lnwire.ChannelID) (lnwire.ShortChannelID, error)) error {
 
 	// First, we'll use reflect to obtain a version of the config struct
 	// that allows us to programmatically inspect its fields.
@@ -257,6 +258,9 @@ func (s *subRPCServerConfigs) PopulateDependencies(cfg *Config,
 			subCfgValue.FieldByName("GenAmpInvoiceFeatures").Set(
 				reflect.ValueOf(genAmpInvoiceFeatures),
 			)
+			subCfgValue.FieldByName("GetAlias").Set(
+				reflect.ValueOf(getAlias),
+			)
 
 		case *neutrinorpc.Config:
 			subCfgValue := extractReflectValue(subCfg)