1# Copyright (C) 2003-2007, 2009, 2010 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. 7# 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 11# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 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"""NS-like base classes.""" 17 18import cStringIO 19 20import dns.exception 21import dns.rdata 22import dns.name 23 24class NSBase(dns.rdata.Rdata): 25 """Base class for rdata that is like an NS record. 26 27 @ivar target: the target name of the rdata 28 @type target: dns.name.Name object""" 29 30 __slots__ = ['target'] 31 32 def __init__(self, rdclass, rdtype, target): 33 super(NSBase, self).__init__(rdclass, rdtype) 34 self.target = target 35 36 def to_text(self, origin=None, relativize=True, **kw): 37 target = self.target.choose_relativity(origin, relativize) 38 return str(target) 39 40 def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True): 41 target = tok.get_name() 42 target = target.choose_relativity(origin, relativize) 43 tok.get_eol() 44 return cls(rdclass, rdtype, target) 45 46 from_text = classmethod(from_text) 47 48 def to_wire(self, file, compress = None, origin = None): 49 self.target.to_wire(file, compress, origin) 50 51 def to_digestable(self, origin = None): 52 return self.target.to_digestable(origin) 53 54 def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None): 55 (target, cused) = dns.name.from_wire(wire[: current + rdlen], 56 current) 57 if cused != rdlen: 58 raise dns.exception.FormError 59 if not origin is None: 60 target = target.relativize(origin) 61 return cls(rdclass, rdtype, target) 62 63 from_wire = classmethod(from_wire) 64 65 def choose_relativity(self, origin = None, relativize = True): 66 self.target = self.target.choose_relativity(origin, relativize) 67 68 def _cmp(self, other): 69 return cmp(self.target, other.target) 70 71class UncompressedNS(NSBase): 72 """Base class for rdata that is like an NS record, but whose name 73 is not compressed when convert to DNS wire format, and whose 74 digestable form is not downcased.""" 75 76 def to_wire(self, file, compress = None, origin = None): 77 super(UncompressedNS, self).to_wire(file, None, origin) 78 79 def to_digestable(self, origin = None): 80 f = cStringIO.StringIO() 81 self.to_wire(f, None, origin) 82 return f.getvalue() 83