Current File : //lib/python3/dist-packages/dns/opcode.py
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
# Copyright (C) 2001-2017 Nominum, Inc.
#
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# documentation for any purpose with or without fee is hereby granted,
# provided that the above copyright notice and this permission notice
# appear in all copies.
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# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""DNS Opcodes."""
import dns.enum
import dns.exception
class Opcode(dns.enum.IntEnum):
#: Query
QUERY = 0
#: Inverse Query (historical)
IQUERY = 1
#: Server Status (unspecified and unimplemented anywhere)
STATUS = 2
#: Notify
NOTIFY = 4
#: Dynamic Update
UPDATE = 5
@classmethod
def _maximum(cls):
return 15
@classmethod
def _unknown_exception_class(cls):
return UnknownOpcode
class UnknownOpcode(dns.exception.DNSException):
"""An DNS opcode is unknown."""
def from_text(text: str) -> Opcode:
"""Convert text into an opcode.
*text*, a ``str``, the textual opcode
Raises ``dns.opcode.UnknownOpcode`` if the opcode is unknown.
Returns an ``int``.
"""
return Opcode.from_text(text)
def from_flags(flags: int) -> Opcode:
"""Extract an opcode from DNS message flags.
*flags*, an ``int``, the DNS flags.
Returns an ``int``.
"""
return Opcode((flags & 0x7800) >> 11)
def to_flags(value: Opcode) -> int:
"""Convert an opcode to a value suitable for ORing into DNS message
flags.
*value*, an ``int``, the DNS opcode value.
Returns an ``int``.
"""
return (value << 11) & 0x7800
def to_text(value: Opcode) -> str:
"""Convert an opcode to text.
*value*, an ``int`` the opcode value,
Raises ``dns.opcode.UnknownOpcode`` if the opcode is unknown.
Returns a ``str``.
"""
return Opcode.to_text(value)
def is_update(flags: int) -> bool:
"""Is the opcode in flags UPDATE?
*flags*, an ``int``, the DNS message flags.
Returns a ``bool``.
"""
return from_flags(flags) == Opcode.UPDATE
### BEGIN generated Opcode constants
QUERY = Opcode.QUERY
IQUERY = Opcode.IQUERY
STATUS = Opcode.STATUS
NOTIFY = Opcode.NOTIFY
UPDATE = Opcode.UPDATE
### END generated Opcode constants
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