Function make_response

dns/message.py:1858–1944

Make a message which is a response for the specified query. The message returned is really a response skeleton; it has all of the infrastructure required of a response, but none of the content. Response section(s) which are copied are shallow copies of the matching section(s) in the

(
    query: Message,
    recursion_available: bool = False,
    our_payload: int = 8192,
    fudge: int = 300,
    tsig_error: int = 0,
    pad: int | None = None,
    copy_mode: CopyMode | None = None,
)

def make_response(
    query: Message,
    recursion_available: bool = False,
    our_payload: int = 8192,
    fudge: int = 300,
    tsig_error: int = 0,
    pad: int | None = None,
    copy_mode: CopyMode | None = None,
) -> Message:
    """Make a message which is a response for the specified query.
    The message returned is really a response skeleton; it has all of the infrastructure
    required of a response, but none of the content.

    Response section(s) which are copied are shallow copies of the matching section(s)
    in the query, so the query's RRsets should not be changed.

    *query*, a ``dns.message.Message``, the query to respond to.

    *recursion_available*, a ``bool``, should RA be set in the response?

    *our_payload*, an ``int``, the payload size to advertise in EDNS responses.

    *fudge*, an ``int``, the TSIG time fudge.

    *tsig_error*, an ``int``, the TSIG error.

    *pad*, a non-negative ``int`` or ``None``.  If 0, the default, do not pad; otherwise
    if not ``None`` add padding bytes to make the message size a multiple of *pad*. Note
    that if padding is non-zero, an EDNS PADDING option will always be added to the
    message.  If ``None``, add padding following RFC 8467, namely if the request is
    padded, pad the response to 468 otherwise do not pad.

    *copy_mode*, a ``dns.message.CopyMode`` or ``None``, determines how sections are
    copied.  The default, ``None`` copies sections according to the default for the
    message's opcode, which is currently ``dns.message.CopyMode.QUESTION`` for all
    opcodes.   ``dns.message.CopyMode.QUESTION`` copies only the question section.
    ``dns.message.CopyMode.EVERYTHING`` copies all sections other than OPT or TSIG
    records, which are created appropriately if needed. ``dns.message.CopyMode.NOTHING``
    copies no sections; note that this mode is for server testing purposes and is
    otherwise not recommended for use.  In particular, ``dns.message.is_response()``
    will be ``False`` if you create a response this way and the rcode is not
    ``FORMERR``, ``SERVFAIL``, ``NOTIMP``, or ``REFUSED``.

    Returns a ``dns.message.Message`` object whose specific class is appropriate for the
    query.  For example, if query is a ``dns.update.UpdateMessage``, the response will
    be one too.
    """

    if query.flags & dns.flags.QR:
        raise dns.exception.FormError("specified query message is not a query")
    opcode = query.opcode()
    factory = _message_factory_from_opcode(opcode)
    response = factory(id=query.id)
    response.flags = dns.flags.QR | (query.flags & dns.flags.RD)
    if recursion_available:
        response.flags |= dns.flags.RA
    response.set_opcode(opcode)
    if copy_mode is None: