Function scmDataToTime

timestamp/timestamp_linux.go:56–78

* scmDataToTime parses SocketControlMessage Data field into time.Time. The structure can return up to three timestamps. This is a legacy feature. Only one field is non-zero at any time. Most timestamps are passed in ts[0]. Hardware timestamps are passed in ts[2]. */

(data []byte)

	// 2 x 64bit ints
	size := 16
	// first, try to use hardware timestamps
	ts, err = byteToTime(data[size*2 : size*3])
	if err != nil {
		return ts, err
	}
	// if hw timestamps aren't present, use software timestamps
	// we can't use ts.IsZero because for some crazy reason timestamp parsed using time.Unix()
	// reports IsZero() == false, even if seconds and nanoseconds are zero.
	if ts.UnixNano() == 0 {
		ts, err = byteToTime(data[0:size])
		if err != nil {
			return ts, err
		}
		if ts.UnixNano() == 0 {
			return ts, fmt.Errorf("got zero timestamp")
		}
	}

	return ts, nil
}

// scmDataToSeqID parses SocketControlMessage Data field to get the SequenceID
func scmDataToSeqID(data []byte) (seqID uint32, err error) {
	se := (*unix.SockExtendedErr)(unsafe.Pointer(&data[0]))
	if unix.Errno(se.Errno) != unix.ENOMSG {
		return 0, fmt.Errorf("expected ENOMSG but got %w", unix.Errno(se.Errno))