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# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
# Copyright (C) 2003-2007, 2009-2011 Nominum, Inc.
#
# Permission to use, copy, modify, and distribute this software and its
# 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.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""DNS Dynamic Update Support"""
import dns.message
import dns.name
import dns.opcode
import dns.rdata
import dns.rdataclass
import dns.rdataset
import dns.tsig
class UpdateSection(dns.enum.IntEnum):
"""Update sections"""
ZONE = 0
PREREQ = 1
UPDATE = 2
ADDITIONAL = 3
@classmethod
def _maximum(cls):
return 3
globals().update(UpdateSection.__members__)
class UpdateMessage(dns.message.Message):
_section_enum = UpdateSection
def __init__(self, zone=None, rdclass=dns.rdataclass.IN, keyring=None,
keyname=None, keyalgorithm=dns.tsig.default_algorithm,
id=None):
"""Initialize a new DNS Update object.
See the documentation of the Message class for a complete
description of the keyring dictionary.
*zone*, a ``dns.name.Name``, ``str``, or ``None``, the zone
which is being updated. ``None`` should only be used by dnspython's
message constructors, as a zone is required for the convenience
methods like ``add()``, ``replace()``, etc.
*rdclass*, an ``int`` or ``str``, the class of the zone.
The *keyring*, *keyname*, and *keyalgorithm* parameters are passed to
``use_tsig()``; see its documentation for details.
"""
super().__init__(id=id)
self.flags |= dns.opcode.to_flags(dns.opcode.UPDATE)
if isinstance(zone, str):
zone = dns.name.from_text(zone)
self.origin = zone
rdclass = dns.rdataclass.RdataClass.make(rdclass)
self.zone_rdclass = rdclass
if self.origin:
self.find_rrset(self.zone, self.origin, rdclass, dns.rdatatype.SOA,
create=True, force_unique=True)
if keyring is not None:
self.use_tsig(keyring, keyname, algorithm=keyalgorithm)
@property
def zone(self):
"""The zone section."""
return self.sections[0]
@zone.setter
def zone(self, v):
self.sections[0] = v
@property
def prerequisite(self):
"""The prerequisite section."""
return self.sections[1]
@prerequisite.setter
def prerequisite(self, v):
self.sections[1] = v
@property
def update(self):
"""The update section."""
return self.sections[2]
@update.setter
def update(self, v):
self.sections[2] = v
def _add_rr(self, name, ttl, rd, deleting=None, section=None):
"""Add a single RR to the update section."""
if section is None:
section = self.update
covers = rd.covers()
rrset = self.find_rrset(section, name, self.zone_rdclass, rd.rdtype,
covers, deleting, True, True)
rrset.add(rd, ttl)
def _add(self, replace, section, name, *args):
"""Add records.
*replace* is the replacement mode. If ``False``,
RRs are added to an existing RRset; if ``True``, the RRset
is replaced with the specified contents. The second
argument is the section to add to. The third argument
is always a name. The other arguments can be:
- rdataset...
- ttl, rdata...
- ttl, rdtype, string...
"""
if isinstance(name, str):
name = dns.name.from_text(name, None)
if isinstance(args[0], dns.rdataset.Rdataset):
for rds in args:
if replace:
self.delete(name, rds.rdtype)
for rd in rds:
self._add_rr(name, rds.ttl, rd, section=section)
else:
args = list(args)
ttl = int(args.pop(0))
if isinstance(args[0], dns.rdata.Rdata):
if replace:
self.delete(name, args[0].rdtype)
for rd in args:
self._add_rr(name, ttl, rd, section=section)
else:
rdtype = dns.rdatatype.RdataType.make(args.pop(0))
if replace:
self.delete(name, rdtype)
for s in args:
rd = dns.rdata.from_text(self.zone_rdclass, rdtype, s,
self.origin)
self._add_rr(name, ttl, rd, section=section)
def add(self, name, *args):
"""Add records.
The first argument is always a name. The other
arguments can be:
- rdataset...
- ttl, rdata...
- ttl, rdtype, string...
"""
self._add(False, self.update, name, *args)
def delete(self, name, *args):
"""Delete records.
The first argument is always a name. The other
arguments can be:
- *empty*
- rdataset...
- rdata...
- rdtype, [string...]
"""
if isinstance(name, str):
name = dns.name.from_text(name, None)
if len(args) == 0:
self.find_rrset(self.update, name, dns.rdataclass.ANY,
dns.rdatatype.ANY, dns.rdatatype.NONE,
dns.rdatatype.ANY, True, True)
elif isinstance(args[0], dns.rdataset.Rdataset):
for rds in args:
for rd in rds:
self._add_rr(name, 0, rd, dns.rdataclass.NONE)
else:
args = list(args)
if isinstance(args[0], dns.rdata.Rdata):
for rd in args:
self._add_rr(name, 0, rd, dns.rdataclass.NONE)
else:
rdtype = dns.rdatatype.RdataType.make(args.pop(0))
if len(args) == 0:
self.find_rrset(self.update, name,
self.zone_rdclass, rdtype,
dns.rdatatype.NONE,
dns.rdataclass.ANY,
True, True)
else:
for s in args:
rd = dns.rdata.from_text(self.zone_rdclass, rdtype, s,
self.origin)
self._add_rr(name, 0, rd, dns.rdataclass.NONE)
def replace(self, name, *args):
"""Replace records.
The first argument is always a name. The other
arguments can be:
- rdataset...
- ttl, rdata...
- ttl, rdtype, string...
Note that if you want to replace the entire node, you should do
a delete of the name followed by one or more calls to add.
"""
self._add(True, self.update, name, *args)
def present(self, name, *args):
"""Require that an owner name (and optionally an rdata type,
or specific rdataset) exists as a prerequisite to the
execution of the update.
The first argument is always a name.
The other arguments can be:
- rdataset...
- rdata...
- rdtype, string...
"""
if isinstance(name, str):
name = dns.name.from_text(name, None)
if len(args) == 0:
self.find_rrset(self.prerequisite, name,
dns.rdataclass.ANY, dns.rdatatype.ANY,
dns.rdatatype.NONE, None,
True, True)
elif isinstance(args[0], dns.rdataset.Rdataset) or \
isinstance(args[0], dns.rdata.Rdata) or \
len(args) > 1:
if not isinstance(args[0], dns.rdataset.Rdataset):
# Add a 0 TTL
args = list(args)
args.insert(0, 0)
self._add(False, self.prerequisite, name, *args)
else:
rdtype = dns.rdatatype.RdataType.make(args[0])
self.find_rrset(self.prerequisite, name,
dns.rdataclass.ANY, rdtype,
dns.rdatatype.NONE, None,
True, True)
def absent(self, name, rdtype=None):
"""Require that an owner name (and optionally an rdata type) does
not exist as a prerequisite to the execution of the update."""
if isinstance(name, str):
name = dns.name.from_text(name, None)
if rdtype is None:
self.find_rrset(self.prerequisite, name,
dns.rdataclass.NONE, dns.rdatatype.ANY,
dns.rdatatype.NONE, None,
True, True)
else:
rdtype = dns.rdatatype.RdataType.make(rdtype)
self.find_rrset(self.prerequisite, name,
dns.rdataclass.NONE, rdtype,
dns.rdatatype.NONE, None,
True, True)
def _get_one_rr_per_rrset(self, value):
# Updates are always one_rr_per_rrset
return True
def _parse_rr_header(self, section, name, rdclass, rdtype):
deleting = None
empty = False
if section == UpdateSection.ZONE:
if dns.rdataclass.is_metaclass(rdclass) or \
rdtype != dns.rdatatype.SOA or \
self.zone:
raise dns.exception.FormError
else:
if not self.zone:
raise dns.exception.FormError
if rdclass in (dns.rdataclass.ANY, dns.rdataclass.NONE):
deleting = rdclass
rdclass = self.zone[0].rdclass
empty = (deleting == dns.rdataclass.ANY or
section == UpdateSection.PREREQ)
return (rdclass, rdtype, deleting, empty)
# backwards compatibility
Update = UpdateMessage
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