1# Copyright (C) 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 16import struct 17 18import dns.rdata 19import dns.rdatatype 20 21class DSBase(dns.rdata.Rdata): 22 """Base class for rdata that is like a DS record 23 24 @ivar key_tag: the key tag 25 @type key_tag: int 26 @ivar algorithm: the algorithm 27 @type algorithm: int 28 @ivar digest_type: the digest type 29 @type digest_type: int 30 @ivar digest: the digest 31 @type digest: int 32 @see: draft-ietf-dnsext-delegation-signer-14.txt""" 33 34 __slots__ = ['key_tag', 'algorithm', 'digest_type', 'digest'] 35 36 def __init__(self, rdclass, rdtype, key_tag, algorithm, digest_type, 37 digest): 38 super(DSBase, self).__init__(rdclass, rdtype) 39 self.key_tag = key_tag 40 self.algorithm = algorithm 41 self.digest_type = digest_type 42 self.digest = digest 43 44 def to_text(self, origin=None, relativize=True, **kw): 45 return '%d %d %d %s' % (self.key_tag, self.algorithm, 46 self.digest_type, 47 dns.rdata._hexify(self.digest, 48 chunksize=128)) 49 50 def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True): 51 key_tag = tok.get_uint16() 52 algorithm = tok.get_uint8() 53 digest_type = tok.get_uint8() 54 chunks = [] 55 while 1: 56 t = tok.get().unescape() 57 if t.is_eol_or_eof(): 58 break 59 if not t.is_identifier(): 60 raise dns.exception.SyntaxError 61 chunks.append(t.value) 62 digest = ''.join(chunks) 63 digest = digest.decode('hex_codec') 64 return cls(rdclass, rdtype, key_tag, algorithm, digest_type, 65 digest) 66 67 from_text = classmethod(from_text) 68 69 def to_wire(self, file, compress = None, origin = None): 70 header = struct.pack("!HBB", self.key_tag, self.algorithm, 71 self.digest_type) 72 file.write(header) 73 file.write(self.digest) 74 75 def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None): 76 header = struct.unpack("!HBB", wire[current : current + 4]) 77 current += 4 78 rdlen -= 4 79 digest = wire[current : current + rdlen] 80 return cls(rdclass, rdtype, header[0], header[1], header[2], digest) 81 82 from_wire = classmethod(from_wire) 83 84 def _cmp(self, other): 85 hs = struct.pack("!HBB", self.key_tag, self.algorithm, 86 self.digest_type) 87 ho = struct.pack("!HBB", other.key_tag, other.algorithm, 88 other.digest_type) 89 v = cmp(hs, ho) 90 if v == 0: 91 v = cmp(self.digest, other.digest) 92 return v 93