lnd/lnwire/extra_bytes.go
Olaoluwa Osuntokun 57b7a668c0
lnwire: add new ChannelType field as TLV record to Open/AcceptChannel
In this commit, we add a new ChannelType field as a new TLV record to
the OpenChannel message. During this change, we make a few tweaks to the
generic TLV encode/decode methods for the ExtraOpaqueData struct to have
it work on the level of tlv.RecordProducer instead of tlv.Record, as
this reduces line noise a bit.

We also partially undo existing logic that would attempt to "prepend"
any new TLV records to the end of the ExtraOpaqueData if one was already
present within the struct. This is based on the assumption that if we've
read a message from disk to order to re-send/transmit it, then the
ExtraOpaqueData is fully populated so we'll write that as is. Otherwise,
a message is being encoded for the first time, and we expect all fields
that are known TLV fields to be specified within the struct itself.

This change required the unit tests to be modified slightly, as we'll
always encode a fresh set of TLV records if none was already specified
within the struct.
2021-08-30 19:17:21 -07:00

118 lines
3.5 KiB
Go

package lnwire
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"github.com/lightningnetwork/lnd/tlv"
)
// 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 properly validate the set of
// signatures that cover these new fields, and ensure we're able to make
// upgrades to the network in a forwards compatible manner.
type ExtraOpaqueData []byte
// Encode attempts to encode the raw extra bytes into the passed io.Writer.
func (e *ExtraOpaqueData) Encode(w *bytes.Buffer) error {
eBytes := []byte((*e)[:])
if err := WriteBytes(w, eBytes); err != nil {
return err
}
return nil
}
// Decode attempts to unpack the raw bytes encoded in the passed io.Reader as a
// set of extra opaque data.
func (e *ExtraOpaqueData) Decode(r io.Reader) error {
// First, we'll attempt to read a set of bytes contained within the
// passed io.Reader (if any exist).
rawBytes, err := ioutil.ReadAll(r)
if err != nil {
return err
}
// If we _do_ have some bytes, then we'll swap out our backing pointer.
// This ensures that any struct that embeds this type will properly
// store the bytes once this method exits.
if len(rawBytes) > 0 {
*e = ExtraOpaqueData(rawBytes)
} else {
*e = make([]byte, 0)
}
return nil
}
// PackRecords attempts to encode the set of tlv records into the target
// ExtraOpaqueData instance. The records will be encoded as a raw TLV stream
// and stored within the backing slice pointer.
func (e *ExtraOpaqueData) PackRecords(recordProducers ...tlv.RecordProducer) error {
// First, assemble all the records passed in in series.
records := make([]tlv.Record, 0, len(recordProducers))
for _, producer := range recordProducers {
records = append(records, producer.Record())
}
// Ensure that the set of records are sorted before we encode them into
// the stream, to ensure they're canonical.
tlv.SortRecords(records)
tlvStream, err := tlv.NewStream(records...)
if err != nil {
return err
}
var extraBytesWriter bytes.Buffer
if err := tlvStream.Encode(&extraBytesWriter); err != nil {
return err
}
*e = ExtraOpaqueData(extraBytesWriter.Bytes())
return nil
}
// ExtractRecords attempts to decode any types in the internal raw bytes as if
// it were a tlv stream. The set of raw parsed types is returned, and any
// passed records (if found in the stream) will be parsed into the proper
// tlv.Record.
func (e *ExtraOpaqueData) ExtractRecords(recordProducers ...tlv.RecordProducer) (
tlv.TypeMap, error) {
// First, assemble all the records passed in in series.
records := make([]tlv.Record, 0, len(recordProducers))
for _, producer := range recordProducers {
records = append(records, producer.Record())
}
extraBytesReader := bytes.NewReader(*e)
tlvStream, err := tlv.NewStream(records...)
if err != nil {
return nil, err
}
return tlvStream.DecodeWithParsedTypes(extraBytesReader)
}
// EncodeMessageExtraData encodes the given recordProducers into the given
// extraData.
func EncodeMessageExtraData(extraData *ExtraOpaqueData,
recordProducers ...tlv.RecordProducer) error {
// Treat extraData as a mutable reference.
if extraData == nil {
return fmt.Errorf("extra data cannot be nil")
}
// Pack in the series of TLV records into this message. The order we
// pass them in doesn't matter, as the method will ensure that things
// are all properly sorted.
return extraData.PackRecords(recordProducers...)
}