lnwire: create new ExtraOpaqueData type for parsing TLV extensions

In this commit, we create a new `ExtraOpaqueData` based on the field
with the same name that's present in all the announcement related
messages. In later commits, we'll embed this new type in each message,
so we'll have a generic way to add/parse TLV extensions from messages.
This commit is contained in:
Olaoluwa Osuntokun 2020-01-27 17:25:01 -08:00 committed by Johan T. Halseth
parent dd6f0ba931
commit a603ac4938
No known key found for this signature in database
GPG Key ID: 15BAADA29DA20D26
3 changed files with 249 additions and 3 deletions

84
lnwire/extra_bytes.go Normal file

@ -0,0 +1,84 @@
package lnwire
import (
"bytes"
"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 io.Writer) error {
eBytes := []byte((*e)[:])
if err := WriteElements(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(records ...tlv.Record) error {
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(records ...tlv.Record) (
tlv.TypeMap, error) {
extraBytesReader := bytes.NewReader(*e)
tlvStream, err := tlv.NewStream(records...)
if err != nil {
return nil, err
}
return tlvStream.DecodeWithParsedTypes(extraBytesReader)
}

147
lnwire/extra_bytes_test.go Normal file

@ -0,0 +1,147 @@
package lnwire
import (
"bytes"
"math/rand"
"reflect"
"testing"
"testing/quick"
"github.com/lightningnetwork/lnd/tlv"
)
// TestExtraOpaqueDataEncodeDecode tests that we're able to encode/decode
// arbitrary payloads.
func TestExtraOpaqueDataEncodeDecode(t *testing.T) {
t.Parallel()
type testCase struct {
// emptyBytes indicates if we should try to encode empty bytes
// or not.
emptyBytes bool
// inputBytes if emptyBytes is false, then we'll read in this
// set of bytes instead.
inputBytes []byte
}
// We should be able to read in an arbitrary set of bytes as an
// ExtraOpaqueData, then encode those new bytes into a new instance.
// The final two instances should be identical.
scenario := func(test testCase) bool {
var (
extraData ExtraOpaqueData
b bytes.Buffer
)
copy(extraData[:], test.inputBytes)
if err := extraData.Encode(&b); err != nil {
t.Fatalf("unable to encode extra data: %v", err)
return false
}
var newBytes ExtraOpaqueData
if err := newBytes.Decode(&b); err != nil {
t.Fatalf("unable to decode extra bytes: %v", err)
return false
}
if !bytes.Equal(extraData[:], newBytes[:]) {
t.Fatalf("expected %x, got %x", extraData,
newBytes)
return false
}
return true
}
// We'll make a function to generate random test data. Half of the
// time, we'll actually feed in blank bytes.
quickCfg := &quick.Config{
Values: func(v []reflect.Value, r *rand.Rand) {
var newTestCase testCase
if r.Int31()%2 == 0 {
newTestCase.emptyBytes = true
}
if !newTestCase.emptyBytes {
numBytes := r.Int31n(1000)
newTestCase.inputBytes = make([]byte, numBytes)
_, err := r.Read(newTestCase.inputBytes)
if err != nil {
t.Fatalf("unable to gen random bytes: %v", err)
return
}
}
v[0] = reflect.ValueOf(newTestCase)
},
}
if err := quick.Check(scenario, quickCfg); err != nil {
t.Fatalf("encode+decode test failed: %v", err)
}
}
// TestExtraOpaqueDataPackUnpackRecords tests that we're able to pack a set of
// tlv.Records into a stream, and unpack them on the other side to obtain the
// same set of records.
func TestExtraOpaqueDataPackUnpackRecords(t *testing.T) {
t.Parallel()
var (
type1 tlv.Type = 1
type2 tlv.Type = 2
channelType1 uint8 = 2
channelType2 uint8
hop1 uint32 = 99
hop2 uint32
)
testRecords := []tlv.Record{
tlv.MakePrimitiveRecord(type1, &channelType1),
tlv.MakePrimitiveRecord(type2, &hop1),
}
// Now that we have our set of sample records and types, we'll encode
// them into the passed ExtraOpaqueData instance.
var extraBytes ExtraOpaqueData
if err := extraBytes.PackRecords(testRecords...); err != nil {
t.Fatalf("unable to pack records: %v", err)
}
// We'll now simulate decoding these types _back_ into records on the
// other side.
newRecords := []tlv.Record{
tlv.MakePrimitiveRecord(type1, &channelType2),
tlv.MakePrimitiveRecord(type2, &hop2),
}
typeMap, err := extraBytes.ExtractRecords(newRecords...)
if err != nil {
t.Fatalf("unable to extract record: %v", err)
}
// We should find that the new backing values have been populated with
// the proper value.
switch {
case channelType1 != channelType2:
t.Fatalf("wrong record for channel type: expected %v, got %v",
channelType1, channelType2)
case hop1 != hop2:
t.Fatalf("wrong record for hop: expected %v, got %v", hop1,
hop2)
}
// Both types we created above should be found in the type map.
if _, ok := typeMap[type1]; !ok {
t.Fatalf("type1 not found in typeMap")
}
if _, ok := typeMap[type2]; !ok {
t.Fatalf("type2 not found in typeMap")
}
}

@ -18,9 +18,16 @@ import (
"github.com/lightningnetwork/lnd/tor"
)
// MaxSliceLength is the maximum allowed length for any opaque byte slices in
// the wire protocol.
const MaxSliceLength = 65535
const (
// MaxSliceLength is the maximum allowed length for any opaque byte
// slices in the wire protocol.
MaxSliceLength = 65535
// MaxMsgBody is the largest payload any message is allowed to provide.
// This is two less than the MaxSliceLength as each message has a 2
// byte type that precedes the message body.
MaxMsgBody = 65533
)
// PkScript is simple type definition which represents a raw serialized public
// key script.
@ -418,6 +425,10 @@ func WriteElement(w io.Writer, element interface{}) error {
if _, err := w.Write(b[:]); err != nil {
return err
}
case ExtraOpaqueData:
return e.Encode(w)
default:
return fmt.Errorf("unknown type in WriteElement: %T", e)
}
@ -824,6 +835,10 @@ func ReadElement(r io.Reader, element interface{}) error {
return err
}
*e = addrBytes[:length]
case *ExtraOpaqueData:
return e.Decode(r)
default:
return fmt.Errorf("unknown type in ReadElement: %T", e)
}