| # Copyright (C) 2003-2007, 2009, 2010 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 |
| |
| 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 |
| @type keyalgorithm: string |
| """ |
| super(Update, self).__init__() |
| self.flags |= dns.opcode.to_flags(dns.opcode.UPDATE) |
| if isinstance(zone, (str, unicode)): |
| zone = dns.name.from_text(zone) |
| self.origin = zone |
| if isinstance(rdclass, str): |
| 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 not keyring is None: |
| self.use_tsig(keyring, keyname, 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, (str, unicode)): |
| 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, str): |
| 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, (str, unicode)): |
| name = dns.name.from_text(name, None) |
| if len(args) == 0: |
| rrset = 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, str): |
| rdtype = dns.rdatatype.from_text(rdtype) |
| if len(args) == 0: |
| rrset = 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, (str, unicode)): |
| name = dns.name.from_text(name, None) |
| if len(args) == 0: |
| rrset = 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, str): |
| rdtype = dns.rdatatype.from_text(rdtype) |
| rrset = 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, (str, unicode)): |
| name = dns.name.from_text(name, None) |
| if rdtype is None: |
| rrset = self.find_rrset(self.answer, name, |
| dns.rdataclass.NONE, dns.rdatatype.ANY, |
| dns.rdatatype.NONE, None, |
| True, True) |
| else: |
| if isinstance(rdtype, str): |
| rdtype = dns.rdatatype.from_text(rdtype) |
| rrset = 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) |
