lib/dnspython/dns/update.py

   1 # Copyright (C) 2003-2007, 2009-2011 Nominum, Inc.
   2 #
   3 # Permission to use, copy, modify, and distribute this software and its
   4 # documentation for any purpose with or without fee is hereby granted,
   5 # provided that the above copyright notice and this permission notice
   6 # appear in all copies.
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   8 # THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
   9 # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10 # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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  12 # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13 # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  14 # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15
  16 """DNS Dynamic Update Support"""
  17
  18 import dns.message
  19 import dns.name
  20 import dns.opcode
  21 import dns.rdata
  22 import dns.rdataclass
  23 import dns.rdataset
  24 import dns.tsig
  25
  26 class Update(dns.message.Message):
  27     def __init__(self, zone, rdclass=dns.rdataclass.IN, keyring=None,
  28                  keyname=None, keyalgorithm=dns.tsig.default_algorithm):
  29         """Initialize a new DNS Update object.
  30
  31         @param zone: The zone which is being updated.
  32         @type zone: A dns.name.Name or string
  33         @param rdclass: The class of the zone; defaults to dns.rdataclass.IN.
  34         @type rdclass: An int designating the class, or a string whose value
  35         is the name of a class.
  36         @param keyring: The TSIG keyring to use; defaults to None.
  37         @type keyring: dict
  38         @param keyname: The name of the TSIG key to use; defaults to None.
  39         The key must be defined in the keyring.  If a keyring is specified
  40         but a keyname is not, then the key used will be the first key in the
  41         keyring.  Note that the order of keys in a dictionary is not defined,
  42         so applications should supply a keyname when a keyring is used, unless
  43         they know the keyring contains only one key.
  44         @type keyname: dns.name.Name or string
  45         @param keyalgorithm: The TSIG algorithm to use; defaults to
  46         dns.tsig.default_algorithm.  Constants for TSIG algorithms are defined
  47         in dns.tsig, and the currently implemented algorithms are
  48         HMAC_MD5, HMAC_SHA1, HMAC_SHA224, HMAC_SHA256, HMAC_SHA384, and
  49         HMAC_SHA512.
  50         @type keyalgorithm: string
  51         """
  52         super(Update, self).__init__()
  53         self.flags |= dns.opcode.to_flags(dns.opcode.UPDATE)
  54         if isinstance(zone, (str, unicode)):
  55             zone = dns.name.from_text(zone)
  56         self.origin = zone
  57         if isinstance(rdclass, str):
  58             rdclass = dns.rdataclass.from_text(rdclass)
  59         self.zone_rdclass = rdclass
  60         self.find_rrset(self.question, self.origin, rdclass, dns.rdatatype.SOA,
  61                         create=True, force_unique=True)
  62         if not keyring is None:
  63             self.use_tsig(keyring, keyname, algorithm=keyalgorithm)
  64
  65     def _add_rr(self, name, ttl, rd, deleting=None, section=None):
  66         """Add a single RR to the update section."""
  67
  68         if section is None:
  69             section = self.authority
  70         covers = rd.covers()
  71         rrset = self.find_rrset(section, name, self.zone_rdclass, rd.rdtype,
  72                                 covers, deleting, True, True)
  73         rrset.add(rd, ttl)
  74
  75     def _add(self, replace, section, name, *args):
  76         """Add records.  The first argument is the replace mode.  If
  77         false, RRs are added to an existing RRset; if true, the RRset
  78         is replaced with the specified contents.  The second
  79         argument is the section to add to.  The third argument
  80         is always a name.  The other arguments can be:
  81
  82                 - rdataset...
  83
  84                 - ttl, rdata...
  85
  86                 - ttl, rdtype, string..."""
  87
  88         if isinstance(name, (str, unicode)):
  89             name = dns.name.from_text(name, None)
  90         if isinstance(args[0], dns.rdataset.Rdataset):
  91             for rds in args:
  92                 if replace:
  93                     self.delete(name, rds.rdtype)
  94                 for rd in rds:
  95                     self._add_rr(name, rds.ttl, rd, section=section)
  96         else:
  97             args = list(args)
  98             ttl = int(args.pop(0))
  99             if isinstance(args[0], dns.rdata.Rdata):
 100                 if replace:
 101                     self.delete(name, args[0].rdtype)
 102                 for rd in args:
 103                     self._add_rr(name, ttl, rd, section=section)
 104             else:
 105                 rdtype = args.pop(0)
 106                 if isinstance(rdtype, str):
 107                     rdtype = dns.rdatatype.from_text(rdtype)
 108                 if replace:
 109                     self.delete(name, rdtype)
 110                 for s in args:
 111                     rd = dns.rdata.from_text(self.zone_rdclass, rdtype, s,
 112                                              self.origin)
 113                     self._add_rr(name, ttl, rd, section=section)
 114
 115     def add(self, name, *args):
 116         """Add records.  The first argument is always a name.  The other
 117         arguments can be:
 118
 119                 - rdataset...
 120
 121                 - ttl, rdata...
 122
 123                 - ttl, rdtype, string..."""
 124         self._add(False, self.authority, name, *args)
 125
 126     def delete(self, name, *args):
 127         """Delete records.  The first argument is always a name.  The other
 128         arguments can be:
 129
 130                 - I{nothing}
 131
 132                 - rdataset...
 133
 134                 - rdata...
 135
 136                 - rdtype, [string...]"""
 137
 138         if isinstance(name, (str, unicode)):
 139             name = dns.name.from_text(name, None)
 140         if len(args) == 0:
 141             rrset = self.find_rrset(self.authority, name, dns.rdataclass.ANY,
 142                                     dns.rdatatype.ANY, dns.rdatatype.NONE,
 143                                     dns.rdatatype.ANY, True, True)
 144         elif isinstance(args[0], dns.rdataset.Rdataset):
 145             for rds in args:
 146                 for rd in rds:
 147                     self._add_rr(name, 0, rd, dns.rdataclass.NONE)
 148         else:
 149             args = list(args)
 150             if isinstance(args[0], dns.rdata.Rdata):
 151                 for rd in args:
 152                     self._add_rr(name, 0, rd, dns.rdataclass.NONE)
 153             else:
 154                 rdtype = args.pop(0)
 155                 if isinstance(rdtype, (str, unicode)):
 156                     rdtype = dns.rdatatype.from_text(rdtype)
 157                 if len(args) == 0:
 158                     rrset = self.find_rrset(self.authority, name,
 159                                             self.zone_rdclass, rdtype,
 160                                             dns.rdatatype.NONE,
 161                                             dns.rdataclass.ANY,
 162                                             True, True)
 163                 else:
 164                     for s in args:
 165                         rd = dns.rdata.from_text(self.zone_rdclass, rdtype, s,
 166                                                  self.origin)
 167                         self._add_rr(name, 0, rd, dns.rdataclass.NONE)
 168
 169     def replace(self, name, *args):
 170         """Replace records.  The first argument is always a name.  The other
 171         arguments can be:
 172
 173                 - rdataset...
 174
 175                 - ttl, rdata...
 176
 177                 - ttl, rdtype, string...
 178
 179         Note that if you want to replace the entire node, you should do
 180         a delete of the name followed by one or more calls to add."""
 181
 182         self._add(True, self.authority, name, *args)
 183
 184     def present(self, name, *args):
 185         """Require that an owner name (and optionally an rdata type,
 186         or specific rdataset) exists as a prerequisite to the
 187         execution of the update.  The first argument is always a name.
 188         The other arguments can be:
 189
 190                 - rdataset...
 191
 192                 - rdata...
 193
 194                 - rdtype, string..."""
 195
 196         if isinstance(name, (str, unicode)):
 197             name = dns.name.from_text(name, None)
 198         if len(args) == 0:
 199             rrset = self.find_rrset(self.answer, name,
 200                                     dns.rdataclass.ANY, dns.rdatatype.ANY,
 201                                     dns.rdatatype.NONE, None,
 202                                     True, True)
 203         elif isinstance(args[0], dns.rdataset.Rdataset) or \
 204              isinstance(args[0], dns.rdata.Rdata) or \
 205              len(args) > 1:
 206             if not isinstance(args[0], dns.rdataset.Rdataset):
 207                 # Add a 0 TTL
 208                 args = list(args)
 209                 args.insert(0, 0)
 210             self._add(False, self.answer, name, *args)
 211         else:
 212             rdtype = args[0]
 213             if isinstance(rdtype, (str, unicode)):
 214                 rdtype = dns.rdatatype.from_text(rdtype)
 215             rrset = self.find_rrset(self.answer, name,
 216                                     dns.rdataclass.ANY, rdtype,
 217                                     dns.rdatatype.NONE, None,
 218                                     True, True)
 219
 220     def absent(self, name, rdtype=None):
 221         """Require that an owner name (and optionally an rdata type) does
 222         not exist as a prerequisite to the execution of the update."""
 223
 224         if isinstance(name, (str, unicode)):
 225             name = dns.name.from_text(name, None)
 226         if rdtype is None:
 227             rrset = self.find_rrset(self.answer, name,
 228                                     dns.rdataclass.NONE, dns.rdatatype.ANY,
 229                                     dns.rdatatype.NONE, None,
 230                                     True, True)
 231         else:
 232             if isinstance(rdtype, (str, unicode)):
 233                 rdtype = dns.rdatatype.from_text(rdtype)
 234             rrset = self.find_rrset(self.answer, name,
 235                                     dns.rdataclass.NONE, rdtype,
 236                                     dns.rdatatype.NONE, None,
 237                                     True, True)
 238
 239     def to_wire(self, origin=None, max_size=65535):
 240         """Return a string containing the update in DNS compressed wire
 241         format.
 242         @rtype: string"""
 243         if origin is None:
 244             origin = self.origin
 245         return super(Update, self).to_wire(origin, max_size)