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250 lines
9.8 KiB
250 lines
9.8 KiB
# Copyright (C) 2003-2007, 2009-2011 Nominum, Inc.
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#
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# Permission to use, copy, modify, and distribute this software and its
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# documentation for any purpose with or without fee is hereby granted,
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# provided that the above copyright notice and this permission notice
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# appear in all copies.
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#
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# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
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# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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"""DNS Dynamic Update Support"""
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import dns.message
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import dns.name
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import dns.opcode
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import dns.rdata
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import dns.rdataclass
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import dns.rdataset
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import dns.tsig
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from ._compat import string_types
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class Update(dns.message.Message):
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def __init__(self, zone, rdclass=dns.rdataclass.IN, keyring=None,
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keyname=None, keyalgorithm=dns.tsig.default_algorithm):
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"""Initialize a new DNS Update object.
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@param zone: The zone which is being updated.
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@type zone: A dns.name.Name or string
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@param rdclass: The class of the zone; defaults to dns.rdataclass.IN.
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@type rdclass: An int designating the class, or a string whose value
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is the name of a class.
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@param keyring: The TSIG keyring to use; defaults to None.
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@type keyring: dict
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@param keyname: The name of the TSIG key to use; defaults to None.
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The key must be defined in the keyring. If a keyring is specified
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but a keyname is not, then the key used will be the first key in the
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keyring. Note that the order of keys in a dictionary is not defined,
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so applications should supply a keyname when a keyring is used, unless
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they know the keyring contains only one key.
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@type keyname: dns.name.Name or string
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@param keyalgorithm: The TSIG algorithm to use; defaults to
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dns.tsig.default_algorithm. Constants for TSIG algorithms are defined
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in dns.tsig, and the currently implemented algorithms are
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HMAC_MD5, HMAC_SHA1, HMAC_SHA224, HMAC_SHA256, HMAC_SHA384, and
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HMAC_SHA512.
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@type keyalgorithm: string
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"""
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super(Update, self).__init__()
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self.flags |= dns.opcode.to_flags(dns.opcode.UPDATE)
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if isinstance(zone, string_types):
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zone = dns.name.from_text(zone)
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self.origin = zone
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if isinstance(rdclass, string_types):
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rdclass = dns.rdataclass.from_text(rdclass)
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self.zone_rdclass = rdclass
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self.find_rrset(self.question, self.origin, rdclass, dns.rdatatype.SOA,
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create=True, force_unique=True)
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if keyring is not None:
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self.use_tsig(keyring, keyname, algorithm=keyalgorithm)
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def _add_rr(self, name, ttl, rd, deleting=None, section=None):
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"""Add a single RR to the update section."""
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if section is None:
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section = self.authority
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covers = rd.covers()
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rrset = self.find_rrset(section, name, self.zone_rdclass, rd.rdtype,
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covers, deleting, True, True)
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rrset.add(rd, ttl)
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def _add(self, replace, section, name, *args):
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"""Add records. The first argument is the replace mode. If
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false, RRs are added to an existing RRset; if true, the RRset
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is replaced with the specified contents. The second
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argument is the section to add to. The third argument
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is always a name. The other arguments can be:
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- rdataset...
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- ttl, rdata...
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- ttl, rdtype, string..."""
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if isinstance(name, string_types):
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name = dns.name.from_text(name, None)
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if isinstance(args[0], dns.rdataset.Rdataset):
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for rds in args:
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if replace:
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self.delete(name, rds.rdtype)
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for rd in rds:
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self._add_rr(name, rds.ttl, rd, section=section)
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else:
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args = list(args)
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ttl = int(args.pop(0))
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if isinstance(args[0], dns.rdata.Rdata):
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if replace:
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self.delete(name, args[0].rdtype)
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for rd in args:
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self._add_rr(name, ttl, rd, section=section)
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else:
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rdtype = args.pop(0)
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if isinstance(rdtype, string_types):
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rdtype = dns.rdatatype.from_text(rdtype)
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if replace:
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self.delete(name, rdtype)
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for s in args:
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rd = dns.rdata.from_text(self.zone_rdclass, rdtype, s,
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self.origin)
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self._add_rr(name, ttl, rd, section=section)
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def add(self, name, *args):
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"""Add records. The first argument is always a name. The other
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arguments can be:
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- rdataset...
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- ttl, rdata...
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- ttl, rdtype, string..."""
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self._add(False, self.authority, name, *args)
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def delete(self, name, *args):
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"""Delete records. The first argument is always a name. The other
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arguments can be:
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- I{nothing}
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- rdataset...
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- rdata...
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- rdtype, [string...]"""
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if isinstance(name, string_types):
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name = dns.name.from_text(name, None)
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if len(args) == 0:
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self.find_rrset(self.authority, name, dns.rdataclass.ANY,
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dns.rdatatype.ANY, dns.rdatatype.NONE,
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dns.rdatatype.ANY, True, True)
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elif isinstance(args[0], dns.rdataset.Rdataset):
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for rds in args:
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for rd in rds:
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self._add_rr(name, 0, rd, dns.rdataclass.NONE)
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else:
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args = list(args)
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if isinstance(args[0], dns.rdata.Rdata):
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for rd in args:
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self._add_rr(name, 0, rd, dns.rdataclass.NONE)
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else:
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rdtype = args.pop(0)
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if isinstance(rdtype, string_types):
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rdtype = dns.rdatatype.from_text(rdtype)
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if len(args) == 0:
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self.find_rrset(self.authority, name,
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self.zone_rdclass, rdtype,
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dns.rdatatype.NONE,
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dns.rdataclass.ANY,
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True, True)
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else:
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for s in args:
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rd = dns.rdata.from_text(self.zone_rdclass, rdtype, s,
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self.origin)
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self._add_rr(name, 0, rd, dns.rdataclass.NONE)
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def replace(self, name, *args):
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"""Replace records. The first argument is always a name. The other
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arguments can be:
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- rdataset...
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- ttl, rdata...
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- ttl, rdtype, string...
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Note that if you want to replace the entire node, you should do
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a delete of the name followed by one or more calls to add."""
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self._add(True, self.authority, name, *args)
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def present(self, name, *args):
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"""Require that an owner name (and optionally an rdata type,
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or specific rdataset) exists as a prerequisite to the
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execution of the update. The first argument is always a name.
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The other arguments can be:
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- rdataset...
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- rdata...
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- rdtype, string..."""
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if isinstance(name, string_types):
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name = dns.name.from_text(name, None)
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if len(args) == 0:
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self.find_rrset(self.answer, name,
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dns.rdataclass.ANY, dns.rdatatype.ANY,
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dns.rdatatype.NONE, None,
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True, True)
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elif isinstance(args[0], dns.rdataset.Rdataset) or \
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isinstance(args[0], dns.rdata.Rdata) or \
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len(args) > 1:
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if not isinstance(args[0], dns.rdataset.Rdataset):
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# Add a 0 TTL
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args = list(args)
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args.insert(0, 0)
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self._add(False, self.answer, name, *args)
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else:
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rdtype = args[0]
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if isinstance(rdtype, string_types):
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rdtype = dns.rdatatype.from_text(rdtype)
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self.find_rrset(self.answer, name,
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dns.rdataclass.ANY, rdtype,
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dns.rdatatype.NONE, None,
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True, True)
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def absent(self, name, rdtype=None):
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"""Require that an owner name (and optionally an rdata type) does
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not exist as a prerequisite to the execution of the update."""
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if isinstance(name, string_types):
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name = dns.name.from_text(name, None)
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if rdtype is None:
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self.find_rrset(self.answer, name,
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dns.rdataclass.NONE, dns.rdatatype.ANY,
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dns.rdatatype.NONE, None,
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True, True)
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else:
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if isinstance(rdtype, string_types):
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rdtype = dns.rdatatype.from_text(rdtype)
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self.find_rrset(self.answer, name,
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dns.rdataclass.NONE, rdtype,
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dns.rdatatype.NONE, None,
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True, True)
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def to_wire(self, origin=None, max_size=65535):
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"""Return a string containing the update in DNS compressed wire
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format.
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@rtype: string"""
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if origin is None:
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origin = self.origin
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return super(Update, self).to_wire(origin, max_size)
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