feat: add inbound fees to channel notifications

docs/release-notes/release-notes-0.18.0.md

@@ -301,6 +301,9 @@
   maintain a healthy connection to the network by checking the number of
   outbound peers if they are below 6.
 
+* [Add inbound fees](https://github.com/lightningnetwork/lnd/pull/8723) to 
+  `subscribeChannelGraph`.
+
 ### Logging
 * [Add the htlc amount](https://github.com/lightningnetwork/lnd/pull/8156) to
   contract court logs in case of timed-out HTLCs in order to easily spot dust
@@ -533,6 +536,7 @@
 * BitcoinerCoderBob
 * bitromortac
 * bota87
+* Bufo
 * Calvin Zachman
 * Carla Kirk-Cohen
 * cristiantroy

routing/notifications.go

@@ -301,6 +301,11 @@ type ChannelEdgeUpdate struct {
 	// Disabled, if true, signals that the channel is unavailable to relay
 	// payments.
 	Disabled bool
+
+	// ExtraOpaqueData is the set of data that was appended to this message
+	// to fill out the full maximum transport message size. These fields can
+	// be used to specify optional data such as custom TLV fields.
+	ExtraOpaqueData lnwire.ExtraOpaqueData
 }
 
 // appendTopologyChange appends the passed update message to the passed
@@ -379,6 +384,7 @@ func addToTopologyChange(graph *channeldb.ChannelGraph, update *TopologyChange,
 			AdvertisingNode: aNode,
 			ConnectingNode:  cNode,
 			Disabled:        m.ChannelFlags&lnwire.ChanUpdateDisabled != 0,
+			ExtraOpaqueData: m.ExtraOpaqueData,
 		}
 
 		// TODO(roasbeef): add bit to toggle

routing/notifications_test.go

@@ -75,7 +75,18 @@ func createTestNode() (*channeldb.LightningNode, error) {
 }
 
 func randEdgePolicy(chanID *lnwire.ShortChannelID,
-	node *channeldb.LightningNode) *models.ChannelEdgePolicy {
+	node *channeldb.LightningNode) (*models.ChannelEdgePolicy, error) {
+
+	InboundFee := models.InboundFee{
+		Base: prand.Int31() * -1,
+		Rate: prand.Int31() * -1,
+	}
+	inboundFee := InboundFee.ToWire()
+
+	var extraOpaqueData lnwire.ExtraOpaqueData
+	if err := extraOpaqueData.PackRecords(&inboundFee); err != nil {
+		return nil, err
+	}
 
 	return &models.ChannelEdgePolicy{
 		SigBytes:                  testSig.Serialize(),
@@ -87,7 +98,8 @@ func randEdgePolicy(chanID *lnwire.ShortChannelID,
 		FeeBaseMSat:               lnwire.MilliSatoshi(prand.Int31()),
 		FeeProportionalMillionths: lnwire.MilliSatoshi(prand.Int31()),
 		ToNode:                    node.PubKeyBytes,
-	}
+		ExtraOpaqueData:           extraOpaqueData,
+	}, nil
 }
 
 func createChannelEdge(ctx *testCtx, bitcoinKey1, bitcoinKey2 []byte,
@@ -457,9 +469,12 @@ func TestEdgeUpdateNotification(t *testing.T) {
 
 	// Create random policy edges that are stemmed to the channel id
 	// created above.
-	edge1 := randEdgePolicy(chanID, node1)
+	edge1, err := randEdgePolicy(chanID, node1)
+	require.NoError(t, err, "unable to create a random chan policy")
 	edge1.ChannelFlags = 0
-	edge2 := randEdgePolicy(chanID, node2)
+
+	edge2, err := randEdgePolicy(chanID, node2)
+	require.NoError(t, err, "unable to create a random chan policy")
 	edge2.ChannelFlags = 1
 
 	if err := ctx.router.UpdateEdge(edge1); err != nil {
@@ -511,6 +526,9 @@ func TestEdgeUpdateNotification(t *testing.T) {
 				"expected %v, got %v", edgeAnn.TimeLockDelta,
 				edgeUpdate.TimeLockDelta)
 		}
+		require.Equal(
+			t, edgeAnn.ExtraOpaqueData, edgeUpdate.ExtraOpaqueData,
+		)
 	}
 
 	// Create lookup map for notifications we are intending to receive. Entries

rpcserver.go

@@ -6691,6 +6691,14 @@ func marshallTopologyChange(topChange *routing.TopologyChange) *lnrpc.GraphTopol
 
 	channelUpdates := make([]*lnrpc.ChannelEdgeUpdate, len(topChange.ChannelEdgeUpdates))
 	for i, channelUpdate := range topChange.ChannelEdgeUpdates {
+
+		customRecords := marshalExtraOpaqueData(
+			channelUpdate.ExtraOpaqueData,
+		)
+		inboundFee := extractInboundFeeSafe(
+			channelUpdate.ExtraOpaqueData,
+		)
+
 		channelUpdates[i] = &lnrpc.ChannelEdgeUpdate{
 			ChanId: channelUpdate.ChanID,
 			ChanPoint: &lnrpc.ChannelPoint{
@@ -6701,12 +6709,25 @@ func marshallTopologyChange(topChange *routing.TopologyChange) *lnrpc.GraphTopol
 			},
 			Capacity: int64(channelUpdate.Capacity),
 			RoutingPolicy: &lnrpc.RoutingPolicy{
-				TimeLockDelta:    uint32(channelUpdate.TimeLockDelta),
-				MinHtlc:          int64(channelUpdate.MinHTLC),
-				MaxHtlcMsat:      uint64(channelUpdate.MaxHTLC),
-				FeeBaseMsat:      int64(channelUpdate.BaseFee),
-				FeeRateMilliMsat: int64(channelUpdate.FeeRate),
+				TimeLockDelta: uint32(
+					channelUpdate.TimeLockDelta,
+				),
+				MinHtlc: int64(
+					channelUpdate.MinHTLC,
+				),
+				MaxHtlcMsat: uint64(
+					channelUpdate.MaxHTLC,
+				),
+				FeeBaseMsat: int64(
+					channelUpdate.BaseFee,
+				),
+				FeeRateMilliMsat: int64(
+					channelUpdate.FeeRate,
+				),
 				Disabled:                channelUpdate.Disabled,
+				InboundFeeBaseMsat:      inboundFee.BaseFee,
+				InboundFeeRateMilliMsat: inboundFee.FeeRate,
+				CustomRecords:           customRecords,
 			},
 			AdvertisingNode: encodeKey(channelUpdate.AdvertisingNode),
 			ConnectingNode:  encodeKey(channelUpdate.ConnectingNode),