Edit File: update.py
# 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 from ._compat import string_types class Update(dns.message.Message): def __init__(self, zone, rdclass=dns.rdataclass.IN, keyring=None, keyname=None, keyalgorithm=dns.tsig.default_algorithm): """Initialize a new DNS Update object. @param zone: The zone which is being updated. @type zone: A dns.name.Name or string @param rdclass: The class of the zone; defaults to dns.rdataclass.IN. @type rdclass: An int designating the class, or a string whose value is the name of a class. @param keyring: The TSIG keyring to use; defaults to None. @type keyring: dict @param keyname: The name of the TSIG key to use; defaults to None. The key must be defined in the keyring. If a keyring is specified but a keyname is not, then the key used will be the first key in the keyring. Note that the order of keys in a dictionary is not defined, so applications should supply a keyname when a keyring is used, unless they know the keyring contains only one key. @type keyname: dns.name.Name or string @param keyalgorithm: The TSIG algorithm to use; defaults to dns.tsig.default_algorithm. Constants for TSIG algorithms are defined in dns.tsig, and the currently implemented algorithms are HMAC_MD5, HMAC_SHA1, HMAC_SHA224, HMAC_SHA256, HMAC_SHA384, and HMAC_SHA512. @type keyalgorithm: string """ super(Update, self).__init__() self.flags |= dns.opcode.to_flags(dns.opcode.UPDATE) if isinstance(zone, string_types): zone = dns.name.from_text(zone) self.origin = zone if isinstance(rdclass, string_types): rdclass = dns.rdataclass.from_text(rdclass) self.zone_rdclass = rdclass self.find_rrset(self.question, self.origin, rdclass, dns.rdatatype.SOA, create=True, force_unique=True) if keyring is not None: self.use_tsig(keyring, keyname, algorithm=keyalgorithm) 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.authority 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. The first argument is the replace 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, string_types): 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 = args.pop(0) if isinstance(rdtype, string_types): rdtype = dns.rdatatype.from_text(rdtype) 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.authority, name, *args) def delete(self, name, *args): """Delete records. The first argument is always a name. The other arguments can be: - I{nothing} - rdataset... - rdata... - rdtype, [string...]""" if isinstance(name, string_types): name = dns.name.from_text(name, None) if len(args) == 0: self.find_rrset(self.authority, 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 = args.pop(0) if isinstance(rdtype, string_types): rdtype = dns.rdatatype.from_text(rdtype) if len(args) == 0: self.find_rrset(self.authority, 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.authority, 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, string_types): name = dns.name.from_text(name, None) if len(args) == 0: self.find_rrset(self.answer, 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.answer, name, *args) else: rdtype = args[0] if isinstance(rdtype, string_types): rdtype = dns.rdatatype.from_text(rdtype) self.find_rrset(self.answer, 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, string_types): name = dns.name.from_text(name, None) if rdtype is None: self.find_rrset(self.answer, name, dns.rdataclass.NONE, dns.rdatatype.ANY, dns.rdatatype.NONE, None, True, True) else: if isinstance(rdtype, string_types): rdtype = dns.rdatatype.from_text(rdtype) self.find_rrset(self.answer, name, dns.rdataclass.NONE, rdtype, dns.rdatatype.NONE, None, True, True) def to_wire(self, origin=None, max_size=65535): """Return a string containing the update in DNS compressed wire format. @rtype: string""" if origin is None: origin = self.origin return super(Update, self).to_wire(origin, max_size)
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