Merge pull request #9897 from ellemouton/inboundFeeTLV

multi: explicitly define InboundFees in ChannelUpdate and ChannelEdgePolicy

discovery/gossiper.go

@@ -3257,6 +3257,7 @@ func (d *AuthenticatedGossiper) handleChanUpdate(ctx context.Context,
 		MaxHTLC:                   upd.HtlcMaximumMsat,
 		FeeBaseMSat:               lnwire.MilliSatoshi(upd.BaseFee),
 		FeeProportionalMillionths: lnwire.MilliSatoshi(upd.FeeRate),
+		InboundFee:                upd.InboundFee.ValOpt(),
 		ExtraOpaqueData:           upd.ExtraOpaqueData,
 	}
 

docs/release-notes/release-notes-0.20.0.md

@@ -88,6 +88,11 @@ circuit. The indices are only available for forwarding events saved after v0.20.
 # Technical and Architectural Updates
 ## BOLT Spec Updates
 
+* Explicitly define the [inbound fee TLV 
+  record](https://github.com/lightningnetwork/lnd/pull/9897) on the 
+  `channel_update` message and handle it explicitly throughout the code base 
+  instead of extracting it from the TLV stream at various call-sites.
+
 ## Testing
 
 ## Database
@@ -99,4 +104,5 @@ circuit. The indices are only available for forwarding events saved after v0.20.
 # Contributors (Alphabetical Order)
 
 * Abdulkbk
-Pins
+* Elle Mouton
+* Pins

go.mod

@@ -203,6 +203,9 @@ require (
 // store have been included in a tagged sqldb version.
 replace github.com/lightningnetwork/lnd/sqldb => ./sqldb
 
+// TODO(elle): replace once the updated tlv package has been tagged.
+replace github.com/lightningnetwork/lnd/tlv => ./tlv
+
 // This replace is for https://github.com/advisories/GHSA-25xm-hr59-7c27
 replace github.com/ulikunitz/xz => github.com/ulikunitz/xz v0.5.11
 

go.sum

@@ -377,8 +377,6 @@ github.com/lightningnetwork/lnd/queue v1.1.1 h1:99ovBlpM9B0FRCGYJo6RSFDlt8/vOkQQ
 github.com/lightningnetwork/lnd/queue v1.1.1/go.mod h1:7A6nC1Qrm32FHuhx/mi1cieAiBZo5O6l8IBIoQxvkz4=
 github.com/lightningnetwork/lnd/ticker v1.1.1 h1:J/b6N2hibFtC7JLV77ULQp++QLtCwT6ijJlbdiZFbSM=
 github.com/lightningnetwork/lnd/ticker v1.1.1/go.mod h1:waPTRAAcwtu7Ji3+3k+u/xH5GHovTsCoSVpho0KDvdA=
-github.com/lightningnetwork/lnd/tlv v1.3.1 h1:o7CZg06y+rJZfUMAo0WzBLr0pgBWCzrt0f9gpujYUzk=
-github.com/lightningnetwork/lnd/tlv v1.3.1/go.mod h1:pJuiBj1ecr1WWLOtcZ+2+hu9Ey25aJWFIsjmAoPPnmc=
 github.com/lightningnetwork/lnd/tor v1.1.6 h1:WHUumk7WgU6BUFsqHuqszI9P6nfhMeIG+rjJBlVE6OE=
 github.com/lightningnetwork/lnd/tor v1.1.6/go.mod h1:qSRB8llhAK+a6kaTPWOLLXSZc6Hg8ZC0mq1sUQ/8JfI=
 github.com/ltcsuite/ltcd v0.0.0-20190101042124-f37f8bf35796 h1:sjOGyegMIhvgfq5oaue6Td+hxZuf3tDC8lAPrFldqFw=

graph/builder.go

@@ -943,7 +943,7 @@ func (b *Builder) ApplyChannelUpdate(msg *lnwire.ChannelUpdate1) bool {
 		return false
 	}
 
-	err = b.UpdateEdge(&models.ChannelEdgePolicy{
+	update := &models.ChannelEdgePolicy{
 		SigBytes:                  msg.Signature.ToSignatureBytes(),
 		ChannelID:                 msg.ShortChannelID.ToUint64(),
 		LastUpdate:                time.Unix(int64(msg.Timestamp), 0),
@@ -954,8 +954,11 @@ func (b *Builder) ApplyChannelUpdate(msg *lnwire.ChannelUpdate1) bool {
 		MaxHTLC:                   msg.HtlcMaximumMsat,
 		FeeBaseMSat:               lnwire.MilliSatoshi(msg.BaseFee),
 		FeeProportionalMillionths: lnwire.MilliSatoshi(msg.FeeRate),
+		InboundFee:                msg.InboundFee.ValOpt(),
 		ExtraOpaqueData:           msg.ExtraOpaqueData,
-	})
+	}
+
+	err = b.UpdateEdge(update)
 	if err != nil && !IsError(err, ErrIgnored, ErrOutdated) {
 		log.Errorf("Unable to apply channel update: %v", err)
 		return false

graph/db/errors.go

@@ -12,6 +12,10 @@ var (
 	ErrEdgePolicyOptionalFieldNotFound = fmt.Errorf("optional field not " +
 		"present")
 
+	// ErrParsingExtraTLVBytes is returned when we attempt to parse
+	// extra opaque bytes as a TLV stream, but the parsing fails.
+	ErrParsingExtraTLVBytes = fmt.Errorf("error parsing extra TLV bytes")
+
 	// ErrGraphNotFound is returned when at least one of the components of
 	// graph doesn't exist.
 	ErrGraphNotFound = fmt.Errorf("graph bucket not initialized")

graph/db/graph_cache.go

@@ -180,17 +180,6 @@ func (c *GraphCache) updateOrAddEdge(node route.Vertex, edge *DirectedChannel) {
 func (c *GraphCache) UpdatePolicy(policy *models.ChannelEdgePolicy, fromNode,
 	toNode route.Vertex, edge1 bool) {
 
-	// Extract inbound fee if possible and available. If there is a decoding
-	// error, ignore this policy.
-	var inboundFee lnwire.Fee
-	_, err := policy.ExtraOpaqueData.ExtractRecords(&inboundFee)
-	if err != nil {
-		log.Errorf("Failed to extract records from edge policy %v: %v",
-			policy.ChannelID, err)
-
-		return
-	}
-
 	c.mtx.Lock()
 	defer c.mtx.Unlock()
 
@@ -216,13 +205,17 @@ func (c *GraphCache) UpdatePolicy(policy *models.ChannelEdgePolicy, fromNode,
 		// policy for node 1.
 		case channel.IsNode1 && edge1:
 			channel.OutPolicySet = true
-			channel.InboundFee = inboundFee
+			policy.InboundFee.WhenSome(func(fee lnwire.Fee) {
+				channel.InboundFee = fee
+			})
 
 		// This is node 2, and it is edge 2, so this is the outgoing
 		// policy for node 2.
 		case !channel.IsNode1 && !edge1:
 			channel.OutPolicySet = true
-			channel.InboundFee = inboundFee
+			policy.InboundFee.WhenSome(func(fee lnwire.Fee) {
+				channel.InboundFee = fee
+			})
 
 		// The other two cases left mean it's the inbound policy for the
 		// node.

graph/db/graph_cache_test.go

@@ -4,6 +4,7 @@ import (
 	"encoding/hex"
 	"testing"
 
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/routing/route"
@@ -37,11 +38,17 @@ func TestGraphCacheAddNode(t *testing.T) {
 			channelFlagA, channelFlagB = 1, 0
 		}
 
+		inboundFee := lnwire.Fee{
+			BaseFee: 10,
+			FeeRate: 20,
+		}
+
 		outPolicy1 := &models.ChannelEdgePolicy{
 			ChannelID:    1000,
 			ChannelFlags: lnwire.ChanUpdateChanFlags(channelFlagA),
 			ToNode:       nodeB,
 			// Define an inbound fee.
+			InboundFee: fn.Some(inboundFee),
 			ExtraOpaqueData: []byte{
 				253, 217, 3, 8, 0, 0, 0, 10, 0, 0, 0, 20,
 			},

graph/db/graph_test.go

@@ -4195,19 +4195,25 @@ func TestGraphCacheForEachNodeChannel(t *testing.T) {
 
 	directedChan := getSingleChannel()
 	require.NotNil(t, directedChan)
-	require.Equal(t, directedChan.InboundFee, lnwire.Fee{
+	expectedInbound := lnwire.Fee{
 		BaseFee: 10,
 		FeeRate: 20,
-	})
+	}
+	require.Equal(t, expectedInbound, directedChan.InboundFee)
 
-	// Set an invalid inbound fee and check that the edge is no longer
-	// returned.
+	// Set an invalid inbound fee and check that persistence fails.
 	edge1.ExtraOpaqueData = []byte{
 		253, 217, 3, 8, 0,
 	}
-	require.NoError(t, graph.UpdateEdgePolicy(edge1))
+	require.ErrorIs(
+		t, graph.UpdateEdgePolicy(edge1), ErrParsingExtraTLVBytes,
+	)
 
-	require.Nil(t, getSingleChannel())
+	// Since persistence of the last update failed, we should still bet
+	// the previous result when we query the channel again.
+	directedChan = getSingleChannel()
+	require.NotNil(t, directedChan)
+	require.Equal(t, expectedInbound, directedChan.InboundFee)
 }
 
 // TestGraphLoading asserts that the cache is properly reconstructed after a

graph/db/kv_store.go

@@ -22,6 +22,7 @@ import (
 	"github.com/btcsuite/btcwallet/walletdb"
 	"github.com/lightningnetwork/lnd/aliasmgr"
 	"github.com/lightningnetwork/lnd/batch"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/kvdb"
@@ -284,6 +285,13 @@ func (c *KVStore) getChannelMap(edges kvdb.RBucket) (
 		case errors.Is(err, ErrEdgePolicyOptionalFieldNotFound):
 			return nil
 
+		// We don't want a single policy with bad TLV data to stop us
+		// from loading the rest of the data, so we just skip this
+		// policy. This is for backwards compatibility since we did not
+		// use to validate TLV data in the past before persisting it.
+		case errors.Is(err, ErrParsingExtraTLVBytes):
+			return nil
+
 		case err != nil:
 			return err
 		}
@@ -474,16 +482,6 @@ func (c *KVStore) forEachNodeDirectedChannel(tx kvdb.RTx,
 			cachedInPolicy.ToNodeFeatures = toNodeFeatures
 		}
 
-		var inboundFee lnwire.Fee
-		if p1 != nil {
-			// Extract inbound fee. If there is a decoding error,
-			// skip this edge.
-			_, err := p1.ExtraOpaqueData.ExtractRecords(&inboundFee)
-			if err != nil {
-				return nil
-			}
-		}
-
 		directedChannel := &DirectedChannel{
 			ChannelID:    e.ChannelID,
 			IsNode1:      node == e.NodeKey1Bytes,
@@ -491,7 +489,12 @@ func (c *KVStore) forEachNodeDirectedChannel(tx kvdb.RTx,
 			Capacity:     e.Capacity,
 			OutPolicySet: p1 != nil,
 			InPolicy:     cachedInPolicy,
-			InboundFee:   inboundFee,
+		}
+
+		if p1 != nil {
+			p1.InboundFee.WhenSome(func(fee lnwire.Fee) {
+				directedChannel.InboundFee = fee
+			})
 		}
 
 		if node == e.NodeKey2Bytes {
@@ -2342,7 +2345,7 @@ func (c *KVStore) FilterChannelRange(startHeight,
 				edge, err := deserializeChanEdgePolicyRaw(r)
 				if err != nil && !errors.Is(
 					err, ErrEdgePolicyOptionalFieldNotFound,
-				) {
+				) && !errors.Is(err, ErrParsingExtraTLVBytes) {
 
 					return err
 				}
@@ -2357,7 +2360,7 @@ func (c *KVStore) FilterChannelRange(startHeight,
 				edge, err := deserializeChanEdgePolicyRaw(r)
 				if err != nil && !errors.Is(
 					err, ErrEdgePolicyOptionalFieldNotFound,
-				) {
+				) && !errors.Is(err, ErrParsingExtraTLVBytes) {
 
 					return err
 				}
@@ -4334,15 +4337,20 @@ func putChanEdgePolicy(edges kvdb.RwBucket, edge *models.ChannelEdgePolicy,
 		// need to deserialize the existing policy within the database
 		// (now outdated by the new one), and delete its corresponding
 		// entry within the update index. We'll ignore any
-		// ErrEdgePolicyOptionalFieldNotFound error, as we only need
-		// the channel ID and update time to delete the entry.
+		// ErrEdgePolicyOptionalFieldNotFound or ErrParsingExtraTLVBytes
+		// errors, as we only need the channel ID and update time to
+		// delete the entry.
+		//
 		// TODO(halseth): get rid of these invalid policies in a
 		// migration.
+		// TODO(elle): complete the above TODO in migration from kvdb
+		// to SQL.
 		oldEdgePolicy, err := deserializeChanEdgePolicy(
 			bytes.NewReader(edgeBytes),
 		)
 		if err != nil &&
-			!errors.Is(err, ErrEdgePolicyOptionalFieldNotFound) {
+			!errors.Is(err, ErrEdgePolicyOptionalFieldNotFound) &&
+			!errors.Is(err, ErrParsingExtraTLVBytes) {
 
 			return err
 		}
@@ -4449,6 +4457,11 @@ func fetchChanEdgePolicy(edges kvdb.RBucket, chanID []byte,
 	case errors.Is(err, ErrEdgePolicyOptionalFieldNotFound):
 		return nil, nil
 
+	// If the policy contains invalid TLV bytes, we return nil as if
+	// the policy was unknown.
+	case errors.Is(err, ErrParsingExtraTLVBytes):
+		return nil, nil
+
 	case err != nil:
 		return nil, err
 	}
@@ -4546,6 +4559,12 @@ func serializeChanEdgePolicy(w io.Writer, edge *models.ChannelEdgePolicy,
 		}
 	}
 
+	// Validate that the ExtraOpaqueData is in fact a valid TLV stream.
+	err = edge.ExtraOpaqueData.ValidateTLV()
+	if err != nil {
+		return fmt.Errorf("%w: %w", ErrParsingExtraTLVBytes, err)
+	}
+
 	if len(edge.ExtraOpaqueData) > MaxAllowedExtraOpaqueBytes {
 		return ErrTooManyExtraOpaqueBytes(len(edge.ExtraOpaqueData))
 	}
@@ -4562,15 +4581,18 @@ func serializeChanEdgePolicy(w io.Writer, edge *models.ChannelEdgePolicy,
 
 func deserializeChanEdgePolicy(r io.Reader) (*models.ChannelEdgePolicy, error) {
 	// Deserialize the policy. Note that in case an optional field is not
-	// found, both an error and a populated policy object are returned.
-	edge, deserializeErr := deserializeChanEdgePolicyRaw(r)
-	if deserializeErr != nil &&
-		!errors.Is(deserializeErr, ErrEdgePolicyOptionalFieldNotFound) {
+	// found or if the edge has invalid TLV data, then both an error and a
+	// populated policy object are returned so that the caller can decide
+	// if it still wants to use the edge or not.
+	edge, err := deserializeChanEdgePolicyRaw(r)
+	if err != nil &&
+		!errors.Is(err, ErrEdgePolicyOptionalFieldNotFound) &&
+		!errors.Is(err, ErrParsingExtraTLVBytes) {
 
-		return nil, deserializeErr
+		return nil, err
 	}
 
-	return edge, deserializeErr
+	return edge, err
 }
 
 func deserializeChanEdgePolicyRaw(r io.Reader) (*models.ChannelEdgePolicy,
@@ -4657,6 +4679,22 @@ func deserializeChanEdgePolicyRaw(r io.Reader) (*models.ChannelEdgePolicy,
 		edge.ExtraOpaqueData = opq[8:]
 	}
 
+	// Attempt to extract the inbound fee from the opaque data. If we fail
+	// to parse the TLV here, we return an error we also return the edge
+	// so that the caller can still use it. This is for backwards
+	// compatibility in case we have already persisted some policies that
+	// have invalid TLV data.
+	var inboundFee lnwire.Fee
+	typeMap, err := edge.ExtraOpaqueData.ExtractRecords(&inboundFee)
+	if err != nil {
+		return edge, fmt.Errorf("%w: %w", ErrParsingExtraTLVBytes, err)
+	}
+
+	val, ok := typeMap[lnwire.FeeRecordType]
+	if ok && val == nil {
+		edge.InboundFee = fn.Some(inboundFee)
+	}
+
 	return edge, nil
 }
 

graph/db/models/channel_edge_policy.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/btcec/v2/ecdsa"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -65,6 +66,15 @@ type ChannelEdgePolicy struct {
 	// to. Using this pub key, the channel graph can further be traversed.
 	ToNode [33]byte
 
+	// InboundFee is the fee that must be paid for incoming HTLCs.
+	//
+	// NOTE: for our kvdb implementation of the graph store, inbound fees
+	// are still only persisted as part of extra opaque data and so this
+	// field is not explicitly stored but is rather populated from the
+	// ExtraOpaqueData field on deserialization. For our SQL implementation,
+	// this field will be explicitly persisted in the database.
+	InboundFee fn.Option[lnwire.Fee]
+
 	// ExtraOpaqueData is the set of data that was appended to this
 	// message, some of which we may not actually know how to iterate or
 	// parse. By holding onto this data, we ensure that we're able to

graph/db/notifications.go

@@ -12,6 +12,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/go-errors/errors"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/lnutils"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -360,6 +361,9 @@ type ChannelEdgeUpdate struct {
 	// payments.
 	Disabled bool
 
+	// InboundFee is the fee that must be paid for incoming HTLCs.
+	InboundFee fn.Option[lnwire.Fee]
+
 	// 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.
@@ -442,6 +446,7 @@ func (c *ChannelGraph) addToTopologyChange(update *TopologyChange,
 			AdvertisingNode: aNode,
 			ConnectingNode:  cNode,
 			Disabled:        m.ChannelFlags&lnwire.ChanUpdateDisabled != 0,
+			InboundFee:      m.InboundFee,
 			ExtraOpaqueData: m.ExtraOpaqueData,
 		}
 

graph/notifications_test.go

@@ -121,6 +121,7 @@ func randEdgePolicy(chanID *lnwire.ShortChannelID,
 		FeeBaseMSat:               lnwire.MilliSatoshi(prand.Int31()),
 		FeeProportionalMillionths: lnwire.MilliSatoshi(prand.Int31()),
 		ToNode:                    node.PubKeyBytes,
+		InboundFee:                fn.Some(inboundFee),
 		ExtraOpaqueData:           extraOpaqueData,
 	}, nil
 }

lnwire/channel_update.go

@@ -6,6 +6,7 @@ import (
 	"io"
 
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/lightningnetwork/lnd/tlv"
 )
 
 // ChanUpdateMsgFlags is a bitfield that signals whether optional fields are
@@ -114,6 +115,10 @@ type ChannelUpdate1 struct {
 	// HtlcMaximumMsat is the maximum HTLC value which will be accepted.
 	HtlcMaximumMsat MilliSatoshi
 
+	// InboundFee is an optional TLV record that contains the fee
+	// information for incoming HTLCs.
+	InboundFee tlv.OptionalRecordT[tlv.TlvType55555, Fee]
+
 	// ExtraData 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.
@@ -156,12 +161,27 @@ func (a *ChannelUpdate1) Decode(r io.Reader, _ uint32) error {
 		}
 	}
 
-	err = a.ExtraOpaqueData.Decode(r)
+	var tlvRecords ExtraOpaqueData
+	if err := ReadElements(r, &tlvRecords); err != nil {
+		return err
+	}
+
+	var inboundFee = a.InboundFee.Zero()
+	typeMap, err := tlvRecords.ExtractRecords(&inboundFee)
 	if err != nil {
 		return err
 	}
 
-	return a.ExtraOpaqueData.ValidateTLV()
+	val, ok := typeMap[a.InboundFee.TlvType()]
+	if ok && val == nil {
+		a.InboundFee = tlv.SomeRecordT(inboundFee)
+	}
+
+	if len(tlvRecords) != 0 {
+		a.ExtraOpaqueData = tlvRecords
+	}
+
+	return nil
 }
 
 // Encode serializes the target ChannelUpdate into the passed io.Writer
@@ -218,6 +238,16 @@ func (a *ChannelUpdate1) Encode(w *bytes.Buffer, pver uint32) error {
 		}
 	}
 
+	recordProducers := make([]tlv.RecordProducer, 0, 1)
+	a.InboundFee.WhenSome(func(fee tlv.RecordT[tlv.TlvType55555, Fee]) {
+		recordProducers = append(recordProducers, &fee)
+	})
+
+	err := EncodeMessageExtraData(&a.ExtraOpaqueData, recordProducers...)
+	if err != nil {
+		return err
+	}
+
 	// Finally, append any extra opaque data.
 	return WriteBytes(w, a.ExtraOpaqueData)
 }

lnwire/test_message.go

@@ -12,6 +12,7 @@ import (
 	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 	"github.com/lightningnetwork/lnd/tlv"
+	"github.com/stretchr/testify/require"
 	"pgregory.net/rapid"
 )
 
@@ -406,6 +407,45 @@ func (a *ChannelUpdate1) RandTestMessage(t *rapid.T) Message {
 		maxHtlc = 0
 	}
 
+	// Randomly decide if an inbound fee should be included.
+	// By default, our extra opaque data will just be random TLV but if we
+	// include an inbound fee, then we will also set the record in the
+	// extra opaque data.
+	var (
+		customRecords, _ = RandCustomRecords(t, nil, false)
+		inboundFee       tlv.OptionalRecordT[tlv.TlvType55555, Fee]
+	)
+	includeInboundFee := rapid.Bool().Draw(t, "includeInboundFee")
+	if includeInboundFee {
+		if customRecords == nil {
+			customRecords = make(CustomRecords)
+		}
+
+		inFeeBase := int32(
+			rapid.IntRange(-1000, 1000).Draw(t, "inFeeBase"),
+		)
+		inFeeProp := int32(
+			rapid.IntRange(-1000, 1000).Draw(t, "inFeeProp"),
+		)
+		fee := Fee{
+			BaseFee: inFeeBase,
+			FeeRate: inFeeProp,
+		}
+		inboundFee = tlv.SomeRecordT(
+			tlv.NewRecordT[tlv.TlvType55555, Fee](fee),
+		)
+
+		var b bytes.Buffer
+		feeRecord := fee.Record()
+		err := feeRecord.Encode(&b)
+		require.NoError(t, err)
+
+		customRecords[uint64(FeeRecordType)] = b.Bytes()
+	}
+
+	extraBytes, err := customRecords.Serialize()
+	require.NoError(t, err)
+
 	return &ChannelUpdate1{
 		Signature:      RandSignature(t),
 		ChainHash:      hash,
@@ -428,7 +468,8 @@ func (a *ChannelUpdate1) RandTestMessage(t *rapid.T) Message {
 			t, "feeRate"),
 		),
 		HtlcMaximumMsat: maxHtlc,
-		ExtraOpaqueData: RandExtraOpaqueData(t, nil),
+		InboundFee:      inboundFee,
+		ExtraOpaqueData: extraBytes,
 	}
 }
 

netann/channel_update.go

@@ -13,6 +13,7 @@ import (
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/lightningnetwork/lnd/tlv"
 	"github.com/pkg/errors"
 )
 
@@ -138,7 +139,7 @@ func ExtractChannelUpdate(ownerPubKey []byte,
 func UnsignedChannelUpdateFromEdge(info *models.ChannelEdgeInfo,
 	policy *models.ChannelEdgePolicy) *lnwire.ChannelUpdate1 {
 
-	return &lnwire.ChannelUpdate1{
+	update := &lnwire.ChannelUpdate1{
 		ChainHash:       info.ChainHash,
 		ShortChannelID:  lnwire.NewShortChanIDFromInt(policy.ChannelID),
 		Timestamp:       uint32(policy.LastUpdate.Unix()),
@@ -151,6 +152,13 @@ func UnsignedChannelUpdateFromEdge(info *models.ChannelEdgeInfo,
 		FeeRate:         uint32(policy.FeeProportionalMillionths),
 		ExtraOpaqueData: policy.ExtraOpaqueData,
 	}
+	policy.InboundFee.WhenSome(func(fee lnwire.Fee) {
+		update.InboundFee = tlv.SomeRecordT(
+			tlv.NewRecordT[tlv.TlvType55555, lnwire.Fee](fee),
+		)
+	})
+
+	return update
 }
 
 // ChannelUpdateFromEdge reconstructs a signed ChannelUpdate from the given edge

peer/brontide.go

@@ -1205,27 +1205,17 @@ func (p *Brontide) loadActiveChannels(chans []*channeldb.OpenChannel) (
 		// routing policy into a forwarding policy.
 		var forwardingPolicy *models.ForwardingPolicy
 		if selfPolicy != nil {
-			var inboundWireFee lnwire.Fee
-			_, err := selfPolicy.ExtraOpaqueData.ExtractRecords(
-				&inboundWireFee,
-			)
-			if err != nil {
-				return nil, err
-			}
-
-			inboundFee := models.NewInboundFeeFromWire(
-				inboundWireFee,
-			)
-
 			forwardingPolicy = &models.ForwardingPolicy{
 				MinHTLCOut:    selfPolicy.MinHTLC,
 				MaxHTLC:       selfPolicy.MaxHTLC,
 				BaseFee:       selfPolicy.FeeBaseMSat,
 				FeeRate:       selfPolicy.FeeProportionalMillionths,
 				TimeLockDelta: uint32(selfPolicy.TimeLockDelta),
-
-				InboundFee: inboundFee,
 			}
+			selfPolicy.InboundFee.WhenSome(func(fee lnwire.Fee) {
+				inboundFee := models.NewInboundFeeFromWire(fee)
+				forwardingPolicy.InboundFee = inboundFee
+			})
 		} else {
 			p.log.Warnf("Unable to find our forwarding policy "+
 				"for channel %v, using default values",

routing/localchans/manager.go

@@ -127,12 +127,10 @@ func (r *Manager) UpdatePolicy(newSchema routing.ChannelPolicy,
 			Edge: edge,
 		})
 
-		// Extract inbound fees from the ExtraOpaqueData.
 		var inboundWireFee lnwire.Fee
-		_, err = edge.ExtraOpaqueData.ExtractRecords(&inboundWireFee)
-		if err != nil {
-			return err
-		}
+		edge.InboundFee.WhenSome(func(fee lnwire.Fee) {
+			inboundWireFee = fee
+		})
 		inboundFee := models.NewInboundFeeFromWire(inboundWireFee)
 
 		// Add updated policy to list of policies to send to switch.
@@ -372,6 +370,8 @@ func (r *Manager) updateEdge(chanPoint wire.OutPoint,
 	err = fn.MapOptionZ(newSchema.InboundFee,
 		func(f models.InboundFee) error {
 			inboundWireFee := f.ToWire()
+			edge.InboundFee = fn.Some(inboundWireFee)
+
 			return edge.ExtraOpaqueData.PackRecords(
 				&inboundWireFee,
 			)

routing/pathfind_test.go

@@ -666,15 +666,25 @@ func createTestGraphFromChannels(t *testing.T, useCache bool,
 			return nil, err
 		}
 
-		getExtraData := func(
-			end *testChannelEnd) lnwire.ExtraOpaqueData {
+		getInboundFees := func(
+			end *testChannelEnd) fn.Option[lnwire.Fee] {
 
-			var extraData lnwire.ExtraOpaqueData
 			inboundFee := lnwire.Fee{
 				BaseFee: int32(end.InboundFeeBaseMsat),
 				FeeRate: int32(end.InboundFeeRate),
 			}
-			require.NoError(t, extraData.PackRecords(&inboundFee))
+
+			return fn.Some(inboundFee)
+		}
+		getExtraData := func(
+			end *testChannelEnd) lnwire.ExtraOpaqueData {
+
+			var extraData lnwire.ExtraOpaqueData
+
+			inboundFee := getInboundFees(end)
+			inboundFee.WhenSome(func(fee lnwire.Fee) {
+				require.NoError(t, extraData.PackRecords(&fee))
+			})
 
 			return extraData
 		}
@@ -701,6 +711,7 @@ func createTestGraphFromChannels(t *testing.T, useCache bool,
 				FeeBaseMSat:               node1.FeeBaseMsat,
 				FeeProportionalMillionths: node1.FeeRate,
 				ToNode:                    node2Vertex,
+				InboundFee:                getInboundFees(node1), //nolint:ll
 				ExtraOpaqueData:           getExtraData(node1),
 			}
 			if err := graph.UpdateEdgePolicy(edgePolicy); err != nil {
@@ -731,6 +742,7 @@ func createTestGraphFromChannels(t *testing.T, useCache bool,
 				FeeBaseMSat:               node2.FeeBaseMsat,
 				FeeProportionalMillionths: node2.FeeRate,
 				ToNode:                    node1Vertex,
+				InboundFee:                getInboundFees(node2), //nolint:ll
 				ExtraOpaqueData:           getExtraData(node2),
 			}
 			if err := graph.UpdateEdgePolicy(edgePolicy); err != nil {

rpcserver.go

@@ -6776,23 +6776,6 @@ func marshalExtraOpaqueData(data []byte) map[uint64][]byte {
 	return records
 }
 
-// extractInboundFeeSafe tries to extract the inbound fee from the given extra
-// opaque data tlv block. If parsing fails, a zero inbound fee is returned. This
-// function is typically used on unvalidated data coming stored in the database.
-// There is not much we can do other than ignoring errors here.
-func extractInboundFeeSafe(data lnwire.ExtraOpaqueData) lnwire.Fee {
-	var inboundFee lnwire.Fee
-
-	_, err := data.ExtractRecords(&inboundFee)
-	if err != nil {
-		// Return zero fee. Do not return the inboundFee variable
-		// because it may be undefined.
-		return lnwire.Fee{}
-	}
-
-	return inboundFee
-}
-
 func marshalDBEdge(edgeInfo *models.ChannelEdgeInfo,
 	c1, c2 *models.ChannelEdgePolicy) *lnrpc.ChannelEdge {
 
@@ -6842,7 +6825,7 @@ func marshalDBRoutingPolicy(
 	disabled := policy.ChannelFlags&lnwire.ChanUpdateDisabled != 0
 
 	customRecords := marshalExtraOpaqueData(policy.ExtraOpaqueData)
-	inboundFee := extractInboundFeeSafe(policy.ExtraOpaqueData)
+	inboundFee := policy.InboundFee.UnwrapOr(lnwire.Fee{})
 
 	return &lnrpc.RoutingPolicy{
 		TimeLockDelta:    uint32(policy.TimeLockDelta),
@@ -7349,9 +7332,7 @@ func marshallTopologyChange(
 		customRecords := marshalExtraOpaqueData(
 			channelUpdate.ExtraOpaqueData,
 		)
-		inboundFee := extractInboundFeeSafe(
-			channelUpdate.ExtraOpaqueData,
-		)
+		inboundFee := channelUpdate.InboundFee.UnwrapOr(lnwire.Fee{})
 
 		channelUpdates[i] = &lnrpc.ChannelEdgeUpdate{
 			ChanId: channelUpdate.ChanID,
@@ -7698,14 +7679,9 @@ func (r *rpcServer) FeeReport(ctx context.Context,
 				edgePolicy.FeeProportionalMillionths
 			feeRate := float64(feeRateFixedPoint) / feeBase
 
-			// Decode inbound fee from extra data.
-			var inboundFee lnwire.Fee
-			_, err := edgePolicy.ExtraOpaqueData.ExtractRecords(
-				&inboundFee,
+			inboundFee := edgePolicy.InboundFee.UnwrapOr(
+				lnwire.Fee{},
 			)
-			if err != nil {
-				return err
-			}
 
 			// TODO(roasbeef): also add stats for revenue for each
 			// channel

tlv/internal/gen/gen_tlv_types.go

@@ -22,6 +22,10 @@ const (
 	// second defined unsigned TLV range used in pure TLV messages.
 	pureTLVSecondUnsignedTypeRangeStart uint32 = 3000000000
 
+	// inboundFeeType defines the TLV type used within the channel_update
+	// message to indicate the inbound fee for a channel.
+	inboundFeeType = 55555
+
 	defaultOutputFile = "tlv_types_generated.go"
 )
 
@@ -29,6 +33,7 @@ const (
 var typeMarkers = map[uint32]struct{}{
 	pureTLVSecondSignedTypeRangeStart:   {},
 	pureTLVSecondUnsignedTypeRangeStart: {},
+	inboundFeeType:                      {},
 }
 
 const typeCodeTemplate = `// Code generated by tlv/internal/gen; DO NOT EDIT.

tlv/tlv_types_generated.go

@@ -3012,6 +3012,16 @@ func (t *tlvType300) tlv() {}
 
 type TlvType300 = *tlvType300
 
+type tlvType55555 struct{}
+
+func (t *tlvType55555) TypeVal() Type {
+	return 55555
+}
+
+func (t *tlvType55555) tlv() {}
+
+type TlvType55555 = *tlvType55555
+
 type tlvType65536 struct{}
 
 func (t *tlvType65536) TypeVal() Type {