lnwire+netann: update ChannelUpdate2

such that all fields are now TLV including the signature.

lnwire/channel_update_2.go

@@ -22,10 +22,6 @@ const (
 // HTLCs and other parameters. This message is also used to redeclare initially
 // set channel parameters.
 type ChannelUpdate2 struct {
-	// Signature is used to validate the announced data and prove the
-	// ownership of node id.
-	Signature Sig
-
 	// ChainHash denotes the target chain that this channel was opened
 	// within. This value should be the genesis hash of the target chain.
 	// Along with the short channel ID, this uniquely identifies the
@@ -74,28 +70,29 @@ type ChannelUpdate2 struct {
 	// millionth of a satoshi.
 	FeeProportionalMillionths tlv.RecordT[tlv.TlvType18, uint32]
 
-	// 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 ExtraOpaqueData
+	// Signature is used to validate the announced data and prove the
+	// ownership of node id.
+	Signature tlv.RecordT[tlv.TlvType160, Sig]
+
+	// Any extra fields in the signed range that we do not yet know about,
+	// but we need to keep them for signature validation and to produce a
+	// valid message.
+	ExtraFieldsInSignedRange map[uint64][]byte
+}
+
+// Encode serializes the target ChannelUpdate2 into the passed io.Writer
+// observing the protocol version specified.
+//
+// This is part of the lnwire.Message interface.
+func (c *ChannelUpdate2) Encode(w *bytes.Buffer, _ uint32) error {
+	return EncodePureTLVMessage(c, w)
 }
 
 // Decode deserializes a serialized ChannelUpdate2 stored in the passed
 // io.Reader observing the specified protocol version.
 //
 // This is part of the lnwire.Message interface.
 func (c *ChannelUpdate2) Decode(r io.Reader, _ uint32) error {
-	err := ReadElement(r, &c.Signature)
-	if err != nil {
-		return err
-	}
-	c.Signature.ForceSchnorr()
-
-	return c.DecodeTLVRecords(r)
-}
-
-// DecodeTLVRecords decodes only the TLV section of the message.
-func (c *ChannelUpdate2) DecodeTLVRecords(r io.Reader) error {
 	// First extract into extra opaque data.
 	var tlvRecords ExtraOpaqueData
 	if err := ReadElements(r, &tlvRecords); err != nil {
@@ -111,10 +108,12 @@ func (c *ChannelUpdate2) DecodeTLVRecords(r io.Reader) error {
 		&secondPeer, &c.CLTVExpiryDelta, &c.HTLCMinimumMsat,
 		&c.HTLCMaximumMsat, &c.FeeBaseMsat,
 		&c.FeeProportionalMillionths,
+		&c.Signature,
 	)
 	if err != nil {
 		return err
 	}
+	c.Signature.Val.ForceSchnorr()
 
 	// By default, the chain-hash is the bitcoin mainnet genesis block hash.
 	c.ChainHash.Val = *chaincfg.MainNetParams.GenesisHash
@@ -150,38 +149,21 @@ func (c *ChannelUpdate2) DecodeTLVRecords(r io.Reader) error {
 		c.FeeProportionalMillionths.Val = defaultFeeProportionalMillionths //nolint:lll
 	}
 
-	if len(tlvRecords) != 0 {
-		c.ExtraOpaqueData = tlvRecords
-	}
+	c.ExtraFieldsInSignedRange = ExtraSignedFieldsFromTypeMap(typeMap)
 
 	return nil
 }
 
-// Encode serializes the target ChannelUpdate2 into the passed io.Writer
-// observing the protocol version specified.
+// AllRecords returns all the TLV records for the message. This will include all
+// the records we know about along with any that we don't know about but that
+// fall in the signed TLV range.
 //
-// This is part of the lnwire.Message interface.
-func (c *ChannelUpdate2) Encode(w *bytes.Buffer, _ uint32) error {
-	_, err := w.Write(c.Signature.RawBytes())
-	if err != nil {
-		return err
-	}
-
-	_, err = c.DataToSign()
-	if err != nil {
-		return err
-	}
-
-	return WriteBytes(w, c.ExtraOpaqueData)
-}
+// NOTE: this is part of the PureTLVMessage interface.
+func (c *ChannelUpdate2) AllRecords() []tlv.Record {
+	var recordProducers []tlv.RecordProducer
 
-// DataToSign is used to retrieve part of the announcement message which should
-// be signed. For the ChannelUpdate2 message, this includes the serialised TLV
-// records.
-func (c *ChannelUpdate2) DataToSign() ([]byte, error) {
 	// The chain-hash record is only included if it is _not_ equal to the
 	// bitcoin mainnet genisis block hash.
-	var recordProducers []tlv.RecordProducer
 	if !c.ChainHash.Val.IsEqual(chaincfg.MainNetParams.GenesisHash) {
 		hash := tlv.ZeroRecordT[tlv.TlvType0, [32]byte]()
 		hash.Val = c.ChainHash.Val
@@ -190,7 +172,7 @@ func (c *ChannelUpdate2) DataToSign() ([]byte, error) {
 	}
 
 	recordProducers = append(recordProducers,
-		&c.ShortChannelID, &c.BlockHeight,
+		&c.ShortChannelID, &c.BlockHeight, &c.Signature,
 	)
 
 	// Only include the disable flags if any bit is set.
@@ -225,12 +207,11 @@ func (c *ChannelUpdate2) DataToSign() ([]byte, error) {
 		)
 	}
 
-	err := EncodeMessageExtraData(&c.ExtraOpaqueData, recordProducers...)
-	if err != nil {
-		return nil, err
-	}
+	recordProducers = append(recordProducers, RecordsAsProducers(
+		tlv.MapToRecords(c.ExtraFieldsInSignedRange),
+	)...)
 
-	return c.ExtraOpaqueData, nil
+	return ProduceRecordsSorted(recordProducers...)
 }
 
 // MsgType returns the integer uniquely identifying this message type on the
@@ -241,8 +222,14 @@ func (c *ChannelUpdate2) MsgType() MessageType {
 	return MsgChannelUpdate2
 }
 
-func (c *ChannelUpdate2) ExtraData() ExtraOpaqueData {
-	return c.ExtraOpaqueData
+func (c *ChannelUpdate2) ExtraData() (ExtraOpaqueData, error) {
+	var buf *bytes.Buffer
+	err := EncodeRecordsTo(buf, tlv.MapToRecords(c.ExtraFieldsInSignedRange))
+	if err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
 }
 
 // A compile time check to ensure ChannelUpdate2 implements the

lnwire/lnwire_test.go

@@ -1603,11 +1603,13 @@ func TestLightningWireProtocol(t *testing.T) {
 			v[0] = reflect.ValueOf(req)
 		},
 		MsgChannelUpdate2: func(v []reflect.Value, r *rand.Rand) {
-			req := ChannelUpdate2{
-				Signature:       testSchnorrSig,
-				ExtraOpaqueData: make([]byte, 0),
-			}
+			var req ChannelUpdate2
+
+			req.ExtraFieldsInSignedRange = randSignedRangeRecords(
+				t, r,
+			)
 
+			req.Signature.Val = testSchnorrSig
 			req.ShortChannelID.Val = NewShortChanIDFromInt(
 				uint64(r.Int63()),
 			)
@@ -1668,15 +1670,6 @@ func TestLightningWireProtocol(t *testing.T) {
 					ChanUpdateDisableOutgoing
 			}
 
-			numExtraBytes := r.Int31n(1000)
-			if numExtraBytes > 0 {
-				req.ExtraOpaqueData = make(
-					[]byte, numExtraBytes,
-				)
-				_, err := r.Read(req.ExtraOpaqueData[:])
-				require.NoError(t, err)
-			}
-
 			v[0] = reflect.ValueOf(req)
 		},
 	}

netann/channel_update.go

@@ -235,7 +235,7 @@ func verifyChannelUpdate2Signature(c *lnwire.ChannelUpdate2,
 		return fmt.Errorf("unable to reconstruct message data: %w", err)
 	}
 
-	nodeSig, err := c.Signature.ToSignature()
+	nodeSig, err := c.Signature.Val.ToSignature()
 	if err != nil {
 		return err
 	}
@@ -323,7 +323,7 @@ func ChanUpdate2DigestTag() []byte {
 // chanUpdate2DigestToSign computes the digest of the ChannelUpdate2 message to
 // be signed.
 func chanUpdate2DigestToSign(c *lnwire.ChannelUpdate2) ([]byte, error) {
-	data, err := c.DataToSign()
+	data, err := lnwire.SerialiseFieldsToSign(c)
 	if err != nil {
 		return nil, err
 	}