channeldb: boiler plate code for migration32

In preparation for the commit which will add the main logic for
migration 32 (which will migrate the MC store to use a more minimal
encoding), this commit just adds some of the code that the migration
will need to the package.

channeldb/log.go

@@ -10,6 +10,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb/migration24"
 	"github.com/lightningnetwork/lnd/channeldb/migration30"
 	"github.com/lightningnetwork/lnd/channeldb/migration31"
+	"github.com/lightningnetwork/lnd/channeldb/migration32"
 	"github.com/lightningnetwork/lnd/channeldb/migration_01_to_11"
 	"github.com/lightningnetwork/lnd/kvdb"
 )
@@ -42,5 +43,6 @@ func UseLogger(logger btclog.Logger) {
 	migration24.UseLogger(logger)
 	migration30.UseLogger(logger)
 	migration31.UseLogger(logger)
+	migration32.UseLogger(logger)
 	kvdb.UseLogger(logger)
 }

channeldb/migration32/codec.go

@@ -0,0 +1,146 @@
+package migration32
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+
+	"github.com/btcsuite/btcd/wire"
+	lnwire "github.com/lightningnetwork/lnd/channeldb/migration/lnwire21"
+)
+
+var (
+	// Big endian is the preferred byte order, due to cursor scans over
+	// integer keys iterating in order.
+	byteOrder = binary.BigEndian
+)
+
+// ReadElement is a one-stop utility function to deserialize any datastructure
+// encoded using the serialization format of the database.
+func ReadElement(r io.Reader, element interface{}) error {
+	switch e := element.(type) {
+	case *uint32:
+		if err := binary.Read(r, byteOrder, e); err != nil {
+			return err
+		}
+
+	case *lnwire.MilliSatoshi:
+		var a uint64
+		if err := binary.Read(r, byteOrder, &a); err != nil {
+			return err
+		}
+
+		*e = lnwire.MilliSatoshi(a)
+
+	case *[]byte:
+		bytes, err := wire.ReadVarBytes(r, 0, 66000, "[]byte")
+		if err != nil {
+			return err
+		}
+
+		*e = bytes
+
+	case *int64, *uint64:
+		if err := binary.Read(r, byteOrder, e); err != nil {
+			return err
+		}
+
+	case *bool:
+		if err := binary.Read(r, byteOrder, e); err != nil {
+			return err
+		}
+
+	case *int32:
+		if err := binary.Read(r, byteOrder, e); err != nil {
+			return err
+		}
+
+	default:
+		return UnknownElementType{"ReadElement", e}
+	}
+
+	return nil
+}
+
+// ReadElements deserializes a variable number of elements into the passed
+// io.Reader, with each element being deserialized according to the ReadElement
+// function.
+func ReadElements(r io.Reader, elements ...interface{}) error {
+	for _, element := range elements {
+		err := ReadElement(r, element)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// UnknownElementType is an error returned when the codec is unable to encode or
+// decode a particular type.
+type UnknownElementType struct {
+	method  string
+	element interface{}
+}
+
+// Error returns the name of the method that encountered the error, as well as
+// the type that was unsupported.
+func (e UnknownElementType) Error() string {
+	return fmt.Sprintf("Unknown type in %s: %T", e.method, e.element)
+}
+
+// WriteElement is a one-stop shop to write the big endian representation of
+// any element which is to be serialized for storage on disk. The passed
+// io.Writer should be backed by an appropriately sized byte slice, or be able
+// to dynamically expand to accommodate additional data.
+func WriteElement(w io.Writer, element interface{}) error {
+	switch e := element.(type) {
+	case int64, uint64:
+		if err := binary.Write(w, byteOrder, e); err != nil {
+			return err
+		}
+
+	case uint32:
+		if err := binary.Write(w, byteOrder, e); err != nil {
+			return err
+		}
+
+	case int32:
+		if err := binary.Write(w, byteOrder, e); err != nil {
+			return err
+		}
+
+	case bool:
+		if err := binary.Write(w, byteOrder, e); err != nil {
+			return err
+		}
+
+	case lnwire.MilliSatoshi:
+		if err := binary.Write(w, byteOrder, uint64(e)); err != nil {
+			return err
+		}
+
+	case []byte:
+		if err := wire.WriteVarBytes(w, 0, e); err != nil {
+			return err
+		}
+
+	default:
+		return UnknownElementType{"WriteElement", e}
+	}
+
+	return nil
+}
+
+// WriteElements is writes each element in the elements slice to the passed
+// io.Writer using WriteElement.
+func WriteElements(w io.Writer, elements ...interface{}) error {
+	for _, element := range elements {
+		err := WriteElement(w, element)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

channeldb/migration32/hop.go

@@ -0,0 +1,59 @@
+package migration32
+
+import (
+	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/lightningnetwork/lnd/tlv"
+)
+
+const (
+	// EncryptedDataOnionType is the type used to include encrypted data
+	// provided by the receiver in the onion for use in blinded paths.
+	EncryptedDataOnionType tlv.Type = 10
+
+	// BlindingPointOnionType is the type used to include receiver provided
+	// ephemeral keys in the onion that are used in blinded paths.
+	BlindingPointOnionType tlv.Type = 12
+
+	// MetadataOnionType is the type used in the onion for the payment
+	// metadata.
+	MetadataOnionType tlv.Type = 16
+
+	// TotalAmtMsatBlindedType is the type used in the onion for the total
+	// amount field that is included in the final hop for blinded payments.
+	TotalAmtMsatBlindedType tlv.Type = 18
+)
+
+// NewEncryptedDataRecord creates a tlv.Record that encodes the encrypted_data
+// (type 10) record for an onion payload.
+func NewEncryptedDataRecord(data *[]byte) tlv.Record {
+	return tlv.MakePrimitiveRecord(EncryptedDataOnionType, data)
+}
+
+// NewBlindingPointRecord creates a tlv.Record that encodes the blinding_point
+// (type 12) record for an onion payload.
+func NewBlindingPointRecord(point **btcec.PublicKey) tlv.Record {
+	return tlv.MakePrimitiveRecord(BlindingPointOnionType, point)
+}
+
+// NewMetadataRecord creates a tlv.Record that encodes the metadata (type 10)
+// for an onion payload.
+func NewMetadataRecord(metadata *[]byte) tlv.Record {
+	return tlv.MakeDynamicRecord(
+		MetadataOnionType, metadata,
+		func() uint64 {
+			return uint64(len(*metadata))
+		},
+		tlv.EVarBytes, tlv.DVarBytes,
+	)
+}
+
+// NewTotalAmtMsatBlinded creates a tlv.Record that encodes the
+// total_amount_msat for the final an onion payload within a blinded route.
+func NewTotalAmtMsatBlinded(amt *uint64) tlv.Record {
+	return tlv.MakeDynamicRecord(
+		TotalAmtMsatBlindedType, amt, func() uint64 {
+			return tlv.SizeTUint64(*amt)
+		},
+		tlv.ETUint64, tlv.DTUint64,
+	)
+}

channeldb/migration32/log.go

@@ -0,0 +1,14 @@
+package migration32
+
+import (
+	"github.com/btcsuite/btclog"
+)
+
+// log is a logger that is initialized as disabled.  This means the package will
+// not perform any logging by default until a logger is set.
+var log = btclog.Disabled
+
+// UseLogger uses a specified Logger to output package logging info.
+func UseLogger(logger btclog.Logger) {
+	log = logger
+}

channeldb/migration32/route.go

@@ -0,0 +1,583 @@
+package migration32
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+
+	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/wire"
+	lnwire "github.com/lightningnetwork/lnd/channeldb/migration/lnwire21"
+	"github.com/lightningnetwork/lnd/tlv"
+)
+
+const (
+	// MPPOnionType is the type used in the onion to reference the MPP
+	// fields: total_amt and payment_addr.
+	MPPOnionType tlv.Type = 8
+
+	// AMPOnionType is the type used in the onion to reference the AMP
+	// fields: root_share, set_id, and child_index.
+	AMPOnionType tlv.Type = 14
+)
+
+// VertexSize is the size of the array to store a vertex.
+const VertexSize = 33
+
+// Vertex is a simple alias for the serialization of a compressed Bitcoin
+// public key.
+type Vertex [VertexSize]byte
+
+// Route represents a path through the channel graph which runs over one or
+// more channels in succession. This struct carries all the information
+// required to craft the Sphinx onion packet, and send the payment along the
+// first hop in the path. A route is only selected as valid if all the channels
+// have sufficient capacity to carry the initial payment amount after fees are
+// accounted for.
+type Route struct {
+	// TotalTimeLock is the cumulative (final) time lock across the entire
+	// route. This is the CLTV value that should be extended to the first
+	// hop in the route. All other hops will decrement the time-lock as
+	// advertised, leaving enough time for all hops to wait for or present
+	// the payment preimage to complete the payment.
+	TotalTimeLock uint32
+
+	// TotalAmount is the total amount of funds required to complete a
+	// payment over this route. This value includes the cumulative fees at
+	// each hop. As a result, the HTLC extended to the first-hop in the
+	// route will need to have at least this many satoshis, otherwise the
+	// route will fail at an intermediate node due to an insufficient
+	// amount of fees.
+	TotalAmount lnwire.MilliSatoshi
+
+	// SourcePubKey is the pubkey of the node where this route originates
+	// from.
+	SourcePubKey Vertex
+
+	// Hops contains details concerning the specific forwarding details at
+	// each hop.
+	Hops []*Hop
+
+	// FirstHopAmount is the amount that should actually be sent to the
+	// first hop in the route. This is only different from TotalAmount above
+	// for custom channels where the on-chain amount doesn't necessarily
+	// reflect all the value of an outgoing payment.
+	FirstHopAmount tlv.RecordT[
+		tlv.TlvType0, tlv.BigSizeT[lnwire.MilliSatoshi],
+	]
+
+	// FirstHopWireCustomRecords is a set of custom records that should be
+	// included in the wire message sent to the first hop. This is only set
+	// on custom channels and is used to include additional information
+	// about the actual value of the payment.
+	//
+	// NOTE: Since these records already represent TLV records, and we
+	// enforce them to be in the custom range (e.g. >= 65536), we don't use
+	// another parent record type here. Instead, when serializing the Route
+	// we merge the TLV records together with the custom records and encode
+	// everything as a single TLV stream.
+	FirstHopWireCustomRecords lnwire.CustomRecords
+}
+
+// Hop represents an intermediate or final node of the route. This naming
+// is in line with the definition given in BOLT #4: Onion Routing Protocol.
+// The struct houses the channel along which this hop can be reached and
+// the values necessary to create the HTLC that needs to be sent to the
+// next hop. It is also used to encode the per-hop payload included within
+// the Sphinx packet.
+type Hop struct {
+	// PubKeyBytes is the raw bytes of the public key of the target node.
+	PubKeyBytes Vertex
+
+	// ChannelID is the unique channel ID for the channel. The first 3
+	// bytes are the block height, the next 3 the index within the block,
+	// and the last 2 bytes are the output index for the channel.
+	ChannelID uint64
+
+	// OutgoingTimeLock is the timelock value that should be used when
+	// crafting the _outgoing_ HTLC from this hop.
+	OutgoingTimeLock uint32
+
+	// AmtToForward is the amount that this hop will forward to the next
+	// hop. This value is less than the value that the incoming HTLC
+	// carries as a fee will be subtracted by the hop.
+	AmtToForward lnwire.MilliSatoshi
+
+	// MPP encapsulates the data required for option_mpp. This field should
+	// only be set for the final hop.
+	MPP *MPP
+
+	// AMP encapsulates the data required for option_amp. This field should
+	// only be set for the final hop.
+	AMP *AMP
+
+	// CustomRecords if non-nil are a set of additional TLV records that
+	// should be included in the forwarding instructions for this node.
+	CustomRecords lnwire.CustomRecords
+
+	// LegacyPayload if true, then this signals that this node doesn't
+	// understand the new TLV payload, so we must instead use the legacy
+	// payload.
+	//
+	// NOTE: we should no longer ever create a Hop with Legacy set to true.
+	// The only reason we are keeping this member is that it could be the
+	// case that we have serialised hops persisted to disk where
+	// LegacyPayload is true.
+	LegacyPayload bool
+
+	// Metadata is additional data that is sent along with the payment to
+	// the payee.
+	Metadata []byte
+
+	// EncryptedData is an encrypted data blob includes for hops that are
+	// part of a blinded route.
+	EncryptedData []byte
+
+	// BlindingPoint is an ephemeral public key used by introduction nodes
+	// in blinded routes to unblind their portion of the route and pass on
+	// the next ephemeral key to the next blinded node to do the same.
+	BlindingPoint *btcec.PublicKey
+
+	// TotalAmtMsat is the total amount for a blinded payment, potentially
+	// spread over more than one HTLC. This field should only be set for
+	// the final hop in a blinded path.
+	TotalAmtMsat lnwire.MilliSatoshi
+}
+
+// MPP is a record that encodes the fields necessary for multi-path payments.
+type MPP struct {
+	// paymentAddr is a random, receiver-generated value used to avoid
+	// collisions with concurrent payers.
+	paymentAddr [32]byte
+
+	// totalMsat is the total value of the payment, potentially spread
+	// across more than one HTLC.
+	totalMsat lnwire.MilliSatoshi
+}
+
+// Record returns a tlv.Record that can be used to encode or decode this record.
+func (r *MPP) Record() tlv.Record {
+	// Fixed-size, 32 byte payment address followed by truncated 64-bit
+	// total msat.
+	size := func() uint64 {
+		return 32 + tlv.SizeTUint64(uint64(r.totalMsat))
+	}
+
+	return tlv.MakeDynamicRecord(
+		MPPOnionType, r, size, MPPEncoder, MPPDecoder,
+	)
+}
+
+const (
+	// minMPPLength is the minimum length of a serialized MPP TLV record,
+	// which occurs when the truncated encoding of total_amt_msat takes 0
+	// bytes, leaving only the payment_addr.
+	minMPPLength = 32
+
+	// maxMPPLength is the maximum length of a serialized MPP TLV record,
+	// which occurs when the truncated encoding of total_amt_msat takes 8
+	// bytes.
+	maxMPPLength = 40
+)
+
+// MPPEncoder writes the MPP record to the provided io.Writer.
+func MPPEncoder(w io.Writer, val interface{}, buf *[8]byte) error {
+	if v, ok := val.(*MPP); ok {
+		err := tlv.EBytes32(w, &v.paymentAddr, buf)
+		if err != nil {
+			return err
+		}
+
+		return tlv.ETUint64T(w, uint64(v.totalMsat), buf)
+	}
+
+	return tlv.NewTypeForEncodingErr(val, "MPP")
+}
+
+// MPPDecoder reads the MPP record to the provided io.Reader.
+func MPPDecoder(r io.Reader, val interface{}, buf *[8]byte, l uint64) error {
+	if v, ok := val.(*MPP); ok && minMPPLength <= l && l <= maxMPPLength {
+		if err := tlv.DBytes32(r, &v.paymentAddr, buf, 32); err != nil {
+			return err
+		}
+
+		var total uint64
+		if err := tlv.DTUint64(r, &total, buf, l-32); err != nil {
+			return err
+		}
+		v.totalMsat = lnwire.MilliSatoshi(total)
+
+		return nil
+	}
+
+	return tlv.NewTypeForDecodingErr(val, "MPP", l, maxMPPLength)
+}
+
+// AMP is a record that encodes the fields necessary for atomic multi-path
+// payments.
+type AMP struct {
+	rootShare  [32]byte
+	setID      [32]byte
+	childIndex uint32
+}
+
+// AMPEncoder writes the AMP record to the provided io.Writer.
+func AMPEncoder(w io.Writer, val interface{}, buf *[8]byte) error {
+	if v, ok := val.(*AMP); ok {
+		if err := tlv.EBytes32(w, &v.rootShare, buf); err != nil {
+			return err
+		}
+
+		if err := tlv.EBytes32(w, &v.setID, buf); err != nil {
+			return err
+		}
+
+		return tlv.ETUint32T(w, v.childIndex, buf)
+	}
+
+	return tlv.NewTypeForEncodingErr(val, "AMP")
+}
+
+const (
+	// minAMPLength is the minimum length of a serialized AMP TLV record,
+	// which occurs when the truncated encoding of child_index takes 0
+	// bytes, leaving only the root_share and set_id.
+	minAMPLength = 64
+
+	// maxAMPLength is the maximum length of a serialized AMP TLV record,
+	// which occurs when the truncated encoding of a child_index takes 2
+	// bytes.
+	maxAMPLength = 68
+)
+
+// AMPDecoder reads the AMP record from the provided io.Reader.
+func AMPDecoder(r io.Reader, val interface{}, buf *[8]byte, l uint64) error {
+	if v, ok := val.(*AMP); ok && minAMPLength <= l && l <= maxAMPLength {
+		if err := tlv.DBytes32(r, &v.rootShare, buf, 32); err != nil {
+			return err
+		}
+
+		if err := tlv.DBytes32(r, &v.setID, buf, 32); err != nil {
+			return err
+		}
+
+		return tlv.DTUint32(r, &v.childIndex, buf, l-minAMPLength)
+	}
+
+	return tlv.NewTypeForDecodingErr(val, "AMP", l, maxAMPLength)
+}
+
+// Record returns a tlv.Record that can be used to encode or decode this record.
+func (a *AMP) Record() tlv.Record {
+	return tlv.MakeDynamicRecord(
+		AMPOnionType, a, a.PayloadSize, AMPEncoder, AMPDecoder,
+	)
+}
+
+// PayloadSize returns the size this record takes up in encoded form.
+func (a *AMP) PayloadSize() uint64 {
+	return 32 + 32 + tlv.SizeTUint32(a.childIndex)
+}
+
+// SerializeRoute serializes a route.
+func SerializeRoute(w io.Writer, r Route) error {
+	if err := WriteElements(w,
+		r.TotalTimeLock, r.TotalAmount, r.SourcePubKey[:],
+	); err != nil {
+		return err
+	}
+
+	if err := WriteElements(w, uint32(len(r.Hops))); err != nil {
+		return err
+	}
+
+	for _, h := range r.Hops {
+		if err := serializeHop(w, h); err != nil {
+			return err
+		}
+	}
+
+	// Any new/extra TLV data is encoded in serializeHTLCAttemptInfo!
+
+	return nil
+}
+
+func serializeHop(w io.Writer, h *Hop) error {
+	if err := WriteElements(w,
+		h.PubKeyBytes[:],
+		h.ChannelID,
+		h.OutgoingTimeLock,
+		h.AmtToForward,
+	); err != nil {
+		return err
+	}
+
+	if err := binary.Write(w, byteOrder, h.LegacyPayload); err != nil {
+		return err
+	}
+
+	// For legacy payloads, we don't need to write any TLV records, so
+	// we'll write a zero indicating the our serialized TLV map has no
+	// records.
+	if h.LegacyPayload {
+		return WriteElements(w, uint32(0))
+	}
+
+	// Gather all non-primitive TLV records so that they can be serialized
+	// as a single blob.
+	//
+	// TODO(conner): add migration to unify all fields in a single TLV
+	// blobs. The split approach will cause headaches down the road as more
+	// fields are added, which we can avoid by having a single TLV stream
+	// for all payload fields.
+	var records []tlv.Record
+	if h.MPP != nil {
+		records = append(records, h.MPP.Record())
+	}
+
+	// Add blinding point and encrypted data if present.
+	if h.EncryptedData != nil {
+		records = append(records, NewEncryptedDataRecord(
+			&h.EncryptedData,
+		))
+	}
+
+	if h.BlindingPoint != nil {
+		records = append(records, NewBlindingPointRecord(
+			&h.BlindingPoint,
+		))
+	}
+
+	if h.AMP != nil {
+		records = append(records, h.AMP.Record())
+	}
+
+	if h.Metadata != nil {
+		records = append(records, NewMetadataRecord(&h.Metadata))
+	}
+
+	if h.TotalAmtMsat != 0 {
+		totalMsatInt := uint64(h.TotalAmtMsat)
+		records = append(
+			records, NewTotalAmtMsatBlinded(&totalMsatInt),
+		)
+	}
+
+	// Final sanity check to absolutely rule out custom records that are not
+	// custom and write into the standard range.
+	if err := h.CustomRecords.Validate(); err != nil {
+		return err
+	}
+
+	// Convert custom records to tlv and add to the record list.
+	// MapToRecords sorts the list, so adding it here will keep the list
+	// canonical.
+	tlvRecords := tlv.MapToRecords(h.CustomRecords)
+	records = append(records, tlvRecords...)
+
+	// Otherwise, we'll transform our slice of records into a map of the
+	// raw bytes, then serialize them in-line with a length (number of
+	// elements) prefix.
+	mapRecords, err := tlv.RecordsToMap(records)
+	if err != nil {
+		return err
+	}
+
+	numRecords := uint32(len(mapRecords))
+	if err := WriteElements(w, numRecords); err != nil {
+		return err
+	}
+
+	for recordType, rawBytes := range mapRecords {
+		if err := WriteElements(w, recordType); err != nil {
+			return err
+		}
+
+		if err := wire.WriteVarBytes(w, 0, rawBytes); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// DeserializeRoute deserializes a route.
+func DeserializeRoute(r io.Reader) (Route, error) {
+	rt := Route{}
+	if err := ReadElements(r,
+		&rt.TotalTimeLock, &rt.TotalAmount,
+	); err != nil {
+		return rt, err
+	}
+
+	var pub []byte
+	if err := ReadElements(r, &pub); err != nil {
+		return rt, err
+	}
+	copy(rt.SourcePubKey[:], pub)
+
+	var numHops uint32
+	if err := ReadElements(r, &numHops); err != nil {
+		return rt, err
+	}
+
+	var hops []*Hop
+	for i := uint32(0); i < numHops; i++ {
+		hop, err := deserializeHop(r)
+		if err != nil {
+			return rt, err
+		}
+		hops = append(hops, hop)
+	}
+	rt.Hops = hops
+
+	// Any new/extra TLV data is decoded in deserializeHTLCAttemptInfo!
+
+	return rt, nil
+}
+
+// maxOnionPayloadSize is the largest Sphinx payload possible, so we don't need
+// to read/write a TLV stream larger than this.
+const maxOnionPayloadSize = 1300
+
+func deserializeHop(r io.Reader) (*Hop, error) {
+	h := &Hop{}
+
+	var pub []byte
+	if err := ReadElements(r, &pub); err != nil {
+		return nil, err
+	}
+	copy(h.PubKeyBytes[:], pub)
+
+	if err := ReadElements(r,
+		&h.ChannelID, &h.OutgoingTimeLock, &h.AmtToForward,
+	); err != nil {
+		return nil, err
+	}
+
+	// TODO(roasbeef): change field to allow LegacyPayload false to be the
+	// legacy default?
+	err := binary.Read(r, byteOrder, &h.LegacyPayload)
+	if err != nil {
+		return nil, err
+	}
+
+	var numElements uint32
+	if err := ReadElements(r, &numElements); err != nil {
+		return nil, err
+	}
+
+	// If there're no elements, then we can return early.
+	if numElements == 0 {
+		return h, nil
+	}
+
+	tlvMap := make(map[uint64][]byte)
+	for i := uint32(0); i < numElements; i++ {
+		var tlvType uint64
+		if err := ReadElements(r, &tlvType); err != nil {
+			return nil, err
+		}
+
+		rawRecordBytes, err := wire.ReadVarBytes(
+			r, 0, maxOnionPayloadSize, "tlv",
+		)
+		if err != nil {
+			return nil, err
+		}
+
+		tlvMap[tlvType] = rawRecordBytes
+	}
+
+	// If the MPP type is present, remove it from the generic TLV map and
+	// parse it back into a proper MPP struct.
+	//
+	// TODO(conner): add migration to unify all fields in a single TLV
+	// blobs. The split approach will cause headaches down the road as more
+	// fields are added, which we can avoid by having a single TLV stream
+	// for all payload fields.
+	mppType := uint64(MPPOnionType)
+	if mppBytes, ok := tlvMap[mppType]; ok {
+		delete(tlvMap, mppType)
+
+		var (
+			mpp    = &MPP{}
+			mppRec = mpp.Record()
+			r      = bytes.NewReader(mppBytes)
+		)
+		err := mppRec.Decode(r, uint64(len(mppBytes)))
+		if err != nil {
+			return nil, err
+		}
+		h.MPP = mpp
+	}
+
+	// If encrypted data or blinding key are present, remove them from
+	// the TLV map and parse into proper types.
+	encryptedDataType := uint64(EncryptedDataOnionType)
+	if data, ok := tlvMap[encryptedDataType]; ok {
+		delete(tlvMap, encryptedDataType)
+		h.EncryptedData = data
+	}
+
+	blindingType := uint64(BlindingPointOnionType)
+	if blindingPoint, ok := tlvMap[blindingType]; ok {
+		delete(tlvMap, blindingType)
+
+		h.BlindingPoint, err = btcec.ParsePubKey(blindingPoint)
+		if err != nil {
+			return nil, fmt.Errorf("invalid blinding point: %w",
+				err)
+		}
+	}
+
+	ampType := uint64(AMPOnionType)
+	if ampBytes, ok := tlvMap[ampType]; ok {
+		delete(tlvMap, ampType)
+
+		var (
+			amp    = &AMP{}
+			ampRec = amp.Record()
+			r      = bytes.NewReader(ampBytes)
+		)
+		err := ampRec.Decode(r, uint64(len(ampBytes)))
+		if err != nil {
+			return nil, err
+		}
+		h.AMP = amp
+	}
+
+	// If the metadata type is present, remove it from the tlv map and
+	// populate directly on the hop.
+	metadataType := uint64(MetadataOnionType)
+	if metadata, ok := tlvMap[metadataType]; ok {
+		delete(tlvMap, metadataType)
+
+		h.Metadata = metadata
+	}
+
+	totalAmtMsatType := uint64(TotalAmtMsatBlindedType)
+	if totalAmtMsat, ok := tlvMap[totalAmtMsatType]; ok {
+		delete(tlvMap, totalAmtMsatType)
+
+		var (
+			totalAmtMsatInt uint64
+			buf             [8]byte
+		)
+		if err := tlv.DTUint64(
+			bytes.NewReader(totalAmtMsat),
+			&totalAmtMsatInt,
+			&buf,
+			uint64(len(totalAmtMsat)),
+		); err != nil {
+			return nil, err
+		}
+
+		h.TotalAmtMsat = lnwire.MilliSatoshi(totalAmtMsatInt)
+	}
+
+	h.CustomRecords = tlvMap
+
+	return h, nil
+}