| 1 | # Copyright (C) 2003-2007, 2009, 2010 Nominum, Inc.
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| 2 | #
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| 3 | # Permission to use, copy, modify, and distribute this software and its
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| 4 | # documentation for any purpose with or without fee is hereby granted,
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| 5 | # provided that the above copyright notice and this permission notice
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| 6 | # appear in all copies.
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| 7 | #
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| 8 | # THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
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| 9 | # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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| 10 | # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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| 11 | # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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| 12 | # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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| 13 | # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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| 14 | # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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| 15 |
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| 16 | """DNS Dynamic Update Support"""
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| 17 |
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| 18 | import dns.message
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| 19 | import dns.name
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| 20 | import dns.opcode
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| 21 | import dns.rdata
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| 22 | import dns.rdataclass
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| 23 | import dns.rdataset
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| 24 | import dns.tsig
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| 25 |
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| 26 | class Update(dns.message.Message):
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| 27 | def __init__(self, zone, rdclass=dns.rdataclass.IN, keyring=None,
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| 28 | keyname=None, keyalgorithm=dns.tsig.default_algorithm):
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| 29 | """Initialize a new DNS Update object.
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| 30 |
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| 31 | @param zone: The zone which is being updated.
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| 32 | @type zone: A dns.name.Name or string
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| 33 | @param rdclass: The class of the zone; defaults to dns.rdataclass.IN.
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| 34 | @type rdclass: An int designating the class, or a string whose value
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| 35 | is the name of a class.
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| 36 | @param keyring: The TSIG keyring to use; defaults to None.
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| 37 | @type keyring: dict
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| 38 | @param keyname: The name of the TSIG key to use; defaults to None.
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| 39 | The key must be defined in the keyring. If a keyring is specified
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| 40 | but a keyname is not, then the key used will be the first key in the
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| 41 | keyring. Note that the order of keys in a dictionary is not defined,
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| 42 | so applications should supply a keyname when a keyring is used, unless
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| 43 | they know the keyring contains only one key.
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| 44 | @type keyname: dns.name.Name or string
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| 45 | @param keyalgorithm: The TSIG algorithm to use; defaults to
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| 46 | dns.tsig.default_algorithm. Constants for TSIG algorithms are defined
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| 47 | in dns.tsig, and the currently implemented algorithms are
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| 48 | HMAC_MD5, HMAC_SHA1, HMAC_SHA224, HMAC_SHA256, HMAC_SHA384, and
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| 49 | HMAC_SHA512.
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| 50 | @type keyalgorithm: string
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| 51 | """
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| 52 | super(Update, self).__init__()
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| 53 | self.flags |= dns.opcode.to_flags(dns.opcode.UPDATE)
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| 54 | if isinstance(zone, (str, unicode)):
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| 55 | zone = dns.name.from_text(zone)
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| 56 | self.origin = zone
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| 57 | if isinstance(rdclass, str):
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| 58 | rdclass = dns.rdataclass.from_text(rdclass)
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| 59 | self.zone_rdclass = rdclass
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| 60 | self.find_rrset(self.question, self.origin, rdclass, dns.rdatatype.SOA,
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| 61 | create=True, force_unique=True)
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| 62 | if not keyring is None:
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| 63 | self.use_tsig(keyring, keyname, algorithm=keyalgorithm)
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| 64 |
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| 65 | def _add_rr(self, name, ttl, rd, deleting=None, section=None):
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| 66 | """Add a single RR to the update section."""
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| 67 |
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| 68 | if section is None:
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| 69 | section = self.authority
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| 70 | covers = rd.covers()
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| 71 | rrset = self.find_rrset(section, name, self.zone_rdclass, rd.rdtype,
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| 72 | covers, deleting, True, True)
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| 73 | rrset.add(rd, ttl)
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| 74 |
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| 75 | def _add(self, replace, section, name, *args):
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| 76 | """Add records. The first argument is the replace mode. If
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| 77 | false, RRs are added to an existing RRset; if true, the RRset
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| 78 | is replaced with the specified contents. The second
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| 79 | argument is the section to add to. The third argument
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| 80 | is always a name. The other arguments can be:
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| 81 |
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| 82 | - rdataset...
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| 83 |
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| 84 | - ttl, rdata...
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| 85 |
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| 86 | - ttl, rdtype, string..."""
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| 87 |
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| 88 | if isinstance(name, (str, unicode)):
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| 89 | name = dns.name.from_text(name, None)
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| 90 | if isinstance(args[0], dns.rdataset.Rdataset):
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| 91 | for rds in args:
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| 92 | if replace:
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| 93 | self.delete(name, rds.rdtype)
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| 94 | for rd in rds:
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| 95 | self._add_rr(name, rds.ttl, rd, section=section)
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| 96 | else:
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| 97 | args = list(args)
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| 98 | ttl = int(args.pop(0))
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| 99 | if isinstance(args[0], dns.rdata.Rdata):
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| 100 | if replace:
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| 101 | self.delete(name, args[0].rdtype)
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| 102 | for rd in args:
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| 103 | self._add_rr(name, ttl, rd, section=section)
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| 104 | else:
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| 105 | rdtype = args.pop(0)
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| 106 | if isinstance(rdtype, str):
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| 107 | rdtype = dns.rdatatype.from_text(rdtype)
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| 108 | if replace:
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| 109 | self.delete(name, rdtype)
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| 110 | for s in args:
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| 111 | rd = dns.rdata.from_text(self.zone_rdclass, rdtype, s,
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| 112 | self.origin)
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| 113 | self._add_rr(name, ttl, rd, section=section)
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| 114 |
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| 115 | def add(self, name, *args):
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| 116 | """Add records. The first argument is always a name. The other
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| 117 | arguments can be:
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| 118 |
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| 119 | - rdataset...
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| 120 |
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| 121 | - ttl, rdata...
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| 122 |
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| 123 | - ttl, rdtype, string..."""
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| 124 | self._add(False, self.authority, name, *args)
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| 125 |
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| 126 | def delete(self, name, *args):
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| 127 | """Delete records. The first argument is always a name. The other
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| 128 | arguments can be:
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| 129 |
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| 130 | - I{nothing}
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| 131 |
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| 132 | - rdataset...
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| 133 |
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| 134 | - rdata...
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| 135 |
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| 136 | - rdtype, [string...]"""
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| 137 |
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| 138 | if isinstance(name, (str, unicode)):
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| 139 | name = dns.name.from_text(name, None)
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| 140 | if len(args) == 0:
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| 141 | rrset = self.find_rrset(self.authority, name, dns.rdataclass.ANY,
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| 142 | dns.rdatatype.ANY, dns.rdatatype.NONE,
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| 143 | dns.rdatatype.ANY, True, True)
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| 144 | elif isinstance(args[0], dns.rdataset.Rdataset):
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| 145 | for rds in args:
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| 146 | for rd in rds:
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| 147 | self._add_rr(name, 0, rd, dns.rdataclass.NONE)
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| 148 | else:
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| 149 | args = list(args)
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| 150 | if isinstance(args[0], dns.rdata.Rdata):
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| 151 | for rd in args:
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| 152 | self._add_rr(name, 0, rd, dns.rdataclass.NONE)
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| 153 | else:
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| 154 | rdtype = args.pop(0)
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| 155 | if isinstance(rdtype, (str, unicode)):
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| 156 | rdtype = dns.rdatatype.from_text(rdtype)
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| 157 | if len(args) == 0:
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| 158 | rrset = self.find_rrset(self.authority, name,
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| 159 | self.zone_rdclass, rdtype,
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| 160 | dns.rdatatype.NONE,
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| 161 | dns.rdataclass.ANY,
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| 162 | True, True)
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| 163 | else:
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| 164 | for s in args:
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| 165 | rd = dns.rdata.from_text(self.zone_rdclass, rdtype, s,
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| 166 | self.origin)
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| 167 | self._add_rr(name, 0, rd, dns.rdataclass.NONE)
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| 168 |
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| 169 | def replace(self, name, *args):
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| 170 | """Replace records. The first argument is always a name. The other
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| 171 | arguments can be:
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| 172 |
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| 173 | - rdataset...
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| 174 |
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| 175 | - ttl, rdata...
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| 176 |
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| 177 | - ttl, rdtype, string...
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| 178 |
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| 179 | Note that if you want to replace the entire node, you should do
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| 180 | a delete of the name followed by one or more calls to add."""
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| 181 |
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| 182 | self._add(True, self.authority, name, *args)
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| 183 |
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| 184 | def present(self, name, *args):
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| 185 | """Require that an owner name (and optionally an rdata type,
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| 186 | or specific rdataset) exists as a prerequisite to the
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| 187 | execution of the update. The first argument is always a name.
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| 188 | The other arguments can be:
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| 189 |
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| 190 | - rdataset...
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| 191 |
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| 192 | - rdata...
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| 193 |
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| 194 | - rdtype, string..."""
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| 195 |
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| 196 | if isinstance(name, (str, unicode)):
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| 197 | name = dns.name.from_text(name, None)
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| 198 | if len(args) == 0:
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| 199 | rrset = self.find_rrset(self.answer, name,
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| 200 | dns.rdataclass.ANY, dns.rdatatype.ANY,
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| 201 | dns.rdatatype.NONE, None,
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| 202 | True, True)
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| 203 | elif isinstance(args[0], dns.rdataset.Rdataset) or \
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| 204 | isinstance(args[0], dns.rdata.Rdata) or \
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| 205 | len(args) > 1:
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| 206 | if not isinstance(args[0], dns.rdataset.Rdataset):
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| 207 | # Add a 0 TTL
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| 208 | args = list(args)
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| 209 | args.insert(0, 0)
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| 210 | self._add(False, self.answer, name, *args)
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| 211 | else:
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| 212 | rdtype = args[0]
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| 213 | if isinstance(rdtype, (str, unicode)):
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| 214 | rdtype = dns.rdatatype.from_text(rdtype)
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| 215 | rrset = self.find_rrset(self.answer, name,
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| 216 | dns.rdataclass.ANY, rdtype,
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| 217 | dns.rdatatype.NONE, None,
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| 218 | True, True)
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| 219 |
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| 220 | def absent(self, name, rdtype=None):
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| 221 | """Require that an owner name (and optionally an rdata type) does
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| 222 | not exist as a prerequisite to the execution of the update."""
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| 223 |
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| 224 | if isinstance(name, (str, unicode)):
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| 225 | name = dns.name.from_text(name, None)
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| 226 | if rdtype is None:
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| 227 | rrset = self.find_rrset(self.answer, name,
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| 228 | dns.rdataclass.NONE, dns.rdatatype.ANY,
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| 229 | dns.rdatatype.NONE, None,
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| 230 | True, True)
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| 231 | else:
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| 232 | if isinstance(rdtype, (str, unicode)):
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| 233 | rdtype = dns.rdatatype.from_text(rdtype)
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| 234 | rrset = self.find_rrset(self.answer, name,
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| 235 | dns.rdataclass.NONE, rdtype,
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| 236 | dns.rdatatype.NONE, None,
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| 237 | True, True)
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| 238 |
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| 239 | def to_wire(self, origin=None, max_size=65535):
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| 240 | """Return a string containing the update in DNS compressed wire
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| 241 | format.
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| 242 | @rtype: string"""
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| 243 | if origin is None:
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| 244 | origin = self.origin
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| 245 | return super(Update, self).to_wire(origin, max_size)
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