JezK

Edit File: opcode.py

# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license

# Copyright (C) 2001-2017 Nominum, Inc.
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"""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