lnd/channeldb/models/channel.go
positiveblue 383cb40f8d
multi: create channeldb/models package
Add a new subpackage to `lnd/channeldb` to hold some of the types that
are used in the package itself and in other packages that should not
depend on `channeldb`.
2023-01-16 07:14:55 -08:00

93 lines
2.6 KiB
Go

package models
import (
"encoding/binary"
"fmt"
"io"
"github.com/lightningnetwork/lnd/lnwire"
)
const (
// serializedCircuitKeyLen is the exact length needed to encode a
// serialized CircuitKey.
serializedCircuitKeyLen = 16
)
var (
// ErrInvalidCircuitKeyLen signals that a circuit key could not be
// decoded because the byte slice is of an invalid length.
ErrInvalidCircuitKeyLen = fmt.Errorf("length of serialized circuit " +
"key must be 16 bytes")
)
// CircuitKey is used by a channel to uniquely identify the HTLCs it receives
// from the switch, and is used to purge our in-memory state of HTLCs that have
// already been processed by a link. Two list of CircuitKeys are included in
// each CommitDiff to allow a link to determine which in-memory htlcs directed
// the opening and closing of circuits in the switch's circuit map.
type CircuitKey struct {
// ChanID is the short chanid indicating the HTLC's origin.
//
// NOTE: It is fine for this value to be blank, as this indicates a
// locally-sourced payment.
ChanID lnwire.ShortChannelID
// HtlcID is the unique htlc index predominately assigned by links,
// though can also be assigned by switch in the case of locally-sourced
// payments.
HtlcID uint64
}
// SetBytes deserializes the given bytes into this CircuitKey.
func (k *CircuitKey) SetBytes(bs []byte) error {
if len(bs) != serializedCircuitKeyLen {
return ErrInvalidCircuitKeyLen
}
k.ChanID = lnwire.NewShortChanIDFromInt(
binary.BigEndian.Uint64(bs[:8]))
k.HtlcID = binary.BigEndian.Uint64(bs[8:])
return nil
}
// Bytes returns the serialized bytes for this circuit key.
func (k CircuitKey) Bytes() []byte {
bs := make([]byte, serializedCircuitKeyLen)
binary.BigEndian.PutUint64(bs[:8], k.ChanID.ToUint64())
binary.BigEndian.PutUint64(bs[8:], k.HtlcID)
return bs
}
// Encode writes a CircuitKey to the provided io.Writer.
func (k *CircuitKey) Encode(w io.Writer) error {
var scratch [serializedCircuitKeyLen]byte
binary.BigEndian.PutUint64(scratch[:8], k.ChanID.ToUint64())
binary.BigEndian.PutUint64(scratch[8:], k.HtlcID)
_, err := w.Write(scratch[:])
return err
}
// Decode reads a CircuitKey from the provided io.Reader.
func (k *CircuitKey) Decode(r io.Reader) error {
var scratch [serializedCircuitKeyLen]byte
if _, err := io.ReadFull(r, scratch[:]); err != nil {
return err
}
k.ChanID = lnwire.NewShortChanIDFromInt(
binary.BigEndian.Uint64(scratch[:8]))
k.HtlcID = binary.BigEndian.Uint64(scratch[8:])
return nil
}
// String returns a string representation of the CircuitKey.
func (k CircuitKey) String() string {
return fmt.Sprintf("(Chan ID=%s, HTLC ID=%d)", k.ChanID, k.HtlcID)
}