Function _validate_labels

dns/name.py:320–347

Check for empty labels in the middle of a label sequence, labels that are too long, and for too many labels. Raises ``dns.name.NameTooLong`` if the name as a whole is too long. Raises ``dns.name.EmptyLabel`` if a label is empty (i.e. the root label) and appears in a position other

(labels: Tuple[bytes, ...])

def _validate_labels(labels: Tuple[bytes, ...]) -> None:
    """Check for empty labels in the middle of a label sequence,
    labels that are too long, and for too many labels.

    Raises ``dns.name.NameTooLong`` if the name as a whole is too long.

    Raises ``dns.name.EmptyLabel`` if a label is empty (i.e. the root
    label) and appears in a position other than the end of the label
    sequence

    """

    l = len(labels)
    total = 0
    i = -1
    j = 0
    for label in labels:
        ll = len(label)
        total += ll + 1
        if ll > 63:
            raise LabelTooLong
        if i < 0 and label == b"":
            i = j
        j += 1
    if total > 255:
        raise NameTooLong
    if i >= 0 and i != l - 1:
        raise EmptyLabel


def _maybe_convert_to_binary(label: bytes | str) -> bytes: