XTLS/Xray-core · error

failed to write a packet

Error message

failed to write a packet

What it means

Error "failed to write a packet" thrown in XTLS/Xray-core.

Source

Thrown at proxy/vless/encoding/addons.go:154

}

func (w *LengthPacketWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
	length := mb.Len() // none of mb is nil
	// fmt.Println("Write", length)
	if length == 0 {
		return nil
	}
	defer func() {
		w.cache = w.cache[:0]
	}()
	w.cache = append(w.cache, byte(length>>8), byte(length))
	for i, b := range mb {
		w.cache = append(w.cache, b.Bytes()...)
		b.Release()
		mb[i] = nil
	}
	if _, err := w.Write(w.cache); err != nil {
		return errors.New("failed to write a packet").Base(err)
	}
	return nil
}

func NewLengthPacketReader(reader io.Reader) *LengthPacketReader {
	return &LengthPacketReader{
		Reader: reader,
		cache:  make([]byte, 2),
	}
}

type LengthPacketReader struct {
	io.Reader
	cache []byte
}

func (r *LengthPacketReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
	if _, err := io.ReadFull(r.Reader, r.cache); err != nil { // maybe EOF

View on GitHub (pinned to 7d214f8b09)

When it happens

Trigger: Thrown at proxy/vless/encoding/addons.go:154 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/62e36b236292b520. Report an issue: GitHub.