Protocol changes to support more packet types
parent
13b7a99860
commit
17990e35d9
@ -1,37 +1,221 @@
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package pnyx
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import (
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"encoding"
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"encoding/binary"
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"fmt"
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"github.com/google/uuid"
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)
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type PacketType uint8
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const (
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PACKET_CHANNEL_COMMAND PacketType = iota
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PACKET_CHANNEL_DATA
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PACKET_CHANNEL_PEER
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CHANNEL_HEADER_LEN int = 5
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CHANNEL_COMMAND_LEN = CHANNEL_HEADER_LEN + COMMAND_LENGTH + ID_LENGTH
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CHANNEL_PEER_LEN = CHANNEL_HEADER_LEN + ID_LENGTH
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)
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type Payload interface {
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encoding.BinaryMarshaler
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}
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type Packet struct {
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Type PacketType
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Payload Payload
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}
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func(packet Packet) MarshalBinary() ([]byte, error) {
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payload, err := packet.Payload.MarshalBinary()
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if err != nil {
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return nil, err
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}
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return append([]byte{byte(packet.Type)}, payload...), nil
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}
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func ParsePacket(data []byte) (Payload, error) {
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if len(data) < 1 {
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return nil, fmt.Errorf("Packet too short to parse - %d/1", len(data))
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}
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switch PacketType(data[0]) {
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case PACKET_CHANNEL_DATA:
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return ParseChannelDataPacket(data[1:])
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case PACKET_CHANNEL_COMMAND:
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return ParseChannelCommandPacket(data[1:])
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case PACKET_CHANNEL_PEER:
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return ParseChannelPeerPacket(data[1:])
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default:
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return nil, fmt.Errorf("Don't know how to parse packet type 0x%02x", data[0])
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}
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}
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type ChannelHeader struct {
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Channel ChannelID
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Mode ModeID
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}
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func(packet ChannelHeader) MarshalBinary() ([]byte, error) {
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p := binary.BigEndian.AppendUint32(nil, uint32(packet.Channel))
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return append(p, byte(packet.Mode)), nil
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}
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func ParseChannelHeader(data []byte) (ChannelHeader, error) {
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if len(data) < 5 {
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return ChannelHeader{}, fmt.Errorf("Not enough bytes to parse ChannelPacket(%d/%d)", len(data), 6)
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}
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return ChannelHeader{
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Channel: ChannelID(binary.BigEndian.Uint32(data)),
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Mode: ModeID(data[4]),
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}, nil
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}
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type ChannelCommandPacket struct {
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ChannelHeader
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Command byte
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ReqID uuid.UUID
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Data []byte
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}
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func(packet Packet) String() string {
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return fmt.Sprintf("{Channel: %x, Mode: %x, Data: %x}", packet.Channel, packet.Mode, packet.Data)
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func NewChannelCommandPacket(channel ChannelID, mode ModeID, command byte, data []byte) (*Packet, uuid.UUID) {
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request_id := uuid.New()
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return &Packet{
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Type: PACKET_CHANNEL_COMMAND,
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Payload: ChannelCommandPacket{
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ChannelHeader: ChannelHeader{
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Channel: channel,
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Mode: mode,
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},
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Command: command,
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ReqID: request_id,
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Data: data,
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},
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}, request_id
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}
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func(packet Packet) MarshalBinary() ([]byte, error) {
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p := binary.BigEndian.AppendUint32(nil, uint32(packet.Channel))
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p = append(p, byte(packet.Mode))
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p = append(p, byte(packet.Command))
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return append(p, packet.Data...), nil
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func(packet ChannelCommandPacket) MarshalBinary() ([]byte, error) {
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header, err := packet.ChannelHeader.MarshalBinary()
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if err != nil {
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return nil, err
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}
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func ParsePacket(data []byte) (*Packet, error) {
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if len(data) < 6 {
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return nil, fmt.Errorf("Not enough bytes to parse Packet(%d/%d)", len(data), 6)
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data := append(header, packet.Command)
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data = append(data, packet.ReqID[:]...)
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return append(data, packet.Data...), nil
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}
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func ParseChannelCommandPacket(data []byte) (ChannelCommandPacket, error) {
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if len(data) < CHANNEL_COMMAND_LEN {
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return ChannelCommandPacket{}, fmt.Errorf("Not enough data to decode channel command packet %d/%d", len(data), CHANNEL_COMMAND_LEN)
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}
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header, err := ParseChannelHeader(data[:CHANNEL_HEADER_LEN])
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if err != nil {
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return ChannelCommandPacket{}, err
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}
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command := data[CHANNEL_HEADER_LEN]
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request_id := uuid.UUID(data[CHANNEL_HEADER_LEN+COMMAND_LENGTH:])
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return ChannelCommandPacket{
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ChannelHeader: header,
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Command: command,
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ReqID: request_id,
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Data: data[CHANNEL_COMMAND_LEN:],
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}, nil
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}
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type ChannelPeerPacket struct {
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ChannelHeader
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Peer PeerID
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Data []byte
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}
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func NewChannelPeerPacket(peer PeerID, channel ChannelID, mode ModeID, data []byte) *Packet {
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return &Packet{
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Channel: ChannelID(binary.BigEndian.Uint32(data)),
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Mode: ModeID(data[4]),
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Command: data[5],
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Data: data[6:],
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Type: PACKET_CHANNEL_PEER,
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Payload: ChannelPeerPacket{
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ChannelHeader: ChannelHeader{
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Channel: channel,
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Mode: mode,
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},
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Peer: peer,
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Data: data,
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},
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}
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}
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func(packet ChannelPeerPacket) MarshalBinary() ([]byte, error) {
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header, err := packet.ChannelHeader.MarshalBinary()
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if err != nil {
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return nil, err
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}
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data := append(header, packet.Peer[:]...)
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return append(data, packet.Data...), nil
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}
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func ParseChannelPeerPacket(data []byte) (ChannelPeerPacket, error) {
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if len(data) < CHANNEL_PEER_LEN {
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return ChannelPeerPacket{}, fmt.Errorf("Not enough bytes to parse ServerChannelPacket: %d/%d", len(data), ID_LENGTH)
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}
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header, err := ParseChannelHeader(data)
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if err != nil {
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return ChannelPeerPacket{}, err
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}
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return ChannelPeerPacket{
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ChannelHeader: header,
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Peer: PeerID(data[CHANNEL_HEADER_LEN:]),
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Data: data[CHANNEL_PEER_LEN:],
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}, nil
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}
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type ChannelDataPacket struct {
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ChannelHeader
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Data []byte
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}
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func NewChannelDataPacket(channel ChannelID, mode ModeID, data []byte) *Packet {
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return &Packet{
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Type: PACKET_CHANNEL_DATA,
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Payload: ChannelDataPacket{
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ChannelHeader: ChannelHeader{
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Channel: channel,
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Mode: mode,
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},
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Data: data,
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},
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}
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}
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func(packet ChannelDataPacket) MarshalBinary() ([]byte, error) {
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header, err := packet.ChannelHeader.MarshalBinary()
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if err != nil {
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return nil, err
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}
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return append(header, packet.Data...), nil
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}
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func ParseChannelDataPacket(data []byte) (ChannelDataPacket, error) {
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if len(data) < CHANNEL_HEADER_LEN {
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return ChannelDataPacket{}, fmt.Errorf("Not enough data to parse ChannelDataPacket")
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}
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header, err := ParseChannelHeader(data)
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if err != nil {
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return ChannelDataPacket{}, nil
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}
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return ChannelDataPacket{
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ChannelHeader: header,
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Data: data[CHANNEL_HEADER_LEN:],
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}, nil
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}
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