Package dns :: Module update |
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# Source Code for Module dns.update

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     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)
    246