lnwire: add convenience functions for protocol validation

Author: ProofOfKeags

lnwire/dyn_propose.go

@@ -318,3 +318,87 @@ func (dp *DynPropose) MsgType() MessageType {
 func (dp *DynPropose) SerializedSize() (uint32, error) {
 	return MessageSerializedSize(dp)
 }
+
+// SerializeTlvData takes just the TLV data of DynPropose (which covers all of
+// the parameters on deck for changing) and serializes just this component. The
+// main purpose of this is to make it easier to validate the DynAck signature.
+func (dp *DynPropose) SerializeTlvData() ([]byte, error) {
+	var tlvRecords []tlv.Record
+	dp.DustLimit.WhenSome(func(dl btcutil.Amount) {
+		protoSats := uint64(dl)
+		tlvRecords = append(
+			tlvRecords, tlv.MakePrimitiveRecord(
+				DPDustLimitSatoshis, &protoSats,
+			),
+		)
+	})
+	dp.MaxValueInFlight.WhenSome(func(max MilliSatoshi) {
+		protoSats := uint64(max)
+		tlvRecords = append(
+			tlvRecords, tlv.MakePrimitiveRecord(
+				DPMaxHtlcValueInFlightMsat, &protoSats,
+			),
+		)
+	})
+	dp.ChannelReserve.WhenSome(func(min btcutil.Amount) {
+		channelReserve := uint64(min)
+		tlvRecords = append(
+			tlvRecords, tlv.MakePrimitiveRecord(
+				DPChannelReserveSatoshis, &channelReserve,
+			),
+		)
+	})
+	dp.CsvDelay.WhenSome(func(wait uint16) {
+		tlvRecords = append(
+			tlvRecords, tlv.MakePrimitiveRecord(
+				DPToSelfDelay, &wait,
+			),
+		)
+	})
+	dp.MaxAcceptedHTLCs.WhenSome(func(max uint16) {
+		tlvRecords = append(
+			tlvRecords, tlv.MakePrimitiveRecord(
+				DPMaxAcceptedHtlcs, &max,
+			),
+		)
+	})
+	dp.FundingKey.WhenSome(func(key btcec.PublicKey) {
+		keyScratch := &key
+		tlvRecords = append(
+			tlvRecords, tlv.MakePrimitiveRecord(
+				DPFundingPubkey, &keyScratch,
+			),
+		)
+	})
+	dp.ChannelType.WhenSome(func(ty ChannelType) {
+		tlvRecords = append(
+			tlvRecords, tlv.MakeDynamicRecord(
+				DPChannelType, &ty,
+				ty.featureBitLen,
+				channelTypeEncoder, channelTypeDecoder,
+			),
+		)
+	})
+	dp.KickoffFeerate.WhenSome(func(kickoffFeerate chainfee.SatPerKWeight) {
+		protoSats := uint32(kickoffFeerate)
+		tlvRecords = append(
+			tlvRecords, tlv.MakePrimitiveRecord(
+				DPKickoffFeerate, &protoSats,
+			),
+		)
+	})
+	tlv.SortRecords(tlvRecords)
+
+	tlvStream, err := tlv.NewStream(tlvRecords...)
+	if err != nil {
+		return nil, err
+	}
+
+	var outBuf bytes.Buffer
+	err = tlvStream.Encode(&outBuf)
+	if err != nil {
+		return nil, err
+	}
+
+	return outBuf.Bytes(), nil
+}