Source Code for Module dns.rdtypes.ANY.NSEC

  1  # Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license 
  2   
  3  # Copyright (C) 2004-2007, 2009-2011 Nominum, Inc. 
  4  # 
  5  # Permission to use, copy, modify, and distribute this software and its 
  6  # documentation for any purpose with or without fee is hereby granted, 
  7  # provided that the above copyright notice and this permission notice 
  8  # appear in all copies. 
  9  # 
 10  # THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES 
 11  # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 
 12  # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR 
 13  # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 
 14  # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 
 15  # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 
 16  # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 
 17   
 18  import struct 
 19   
 20  import dns.exception 
 21  import dns.rdata 
 22  import dns.rdatatype 
 23  import dns.name 
 24  from dns._compat import xrange 
 25   
 26   
 27 -class NSEC(dns.rdata.Rdata): 
 28   
 29      """NSEC record 
 30   
 31      @ivar next: the next name 
 32      @type next: dns.name.Name object 
 33      @ivar windows: the windowed bitmap list 
 34      @type windows: list of (window number, string) tuples""" 
 35   
 36      __slots__ = ['next', 'windows'] 
 37   
 38 -    def __init__(self, rdclass, rdtype, next, windows): 
 39          super(NSEC, self).__init__(rdclass, rdtype) 
 40          self.next = next 
 41          self.windows = windows 
 42   
 43 -    def to_text(self, origin=None, relativize=True, **kw): 
 44          next = self.next.choose_relativity(origin, relativize) 
 45          text = '' 
 46          for (window, bitmap) in self.windows: 
 47              bits = [] 
 48              for i in xrange(0, len(bitmap)): 
 49                  byte = bitmap[i] 
 50                  for j in xrange(0, 8): 
 51                      if byte & (0x80 >> j): 
 52                          bits.append(dns.rdatatype.to_text(window * 256 + 
 53                                                            i * 8 + j)) 
 54              text += (' ' + ' '.join(bits)) 
 55          return '{}{}'.format(next, text) 
 56   
 57      @classmethod 
 58 -    def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True): 
 59          next = tok.get_name() 
 60          next = next.choose_relativity(origin, relativize) 
 61          rdtypes = [] 
 62          while 1: 
 63              token = tok.get().unescape() 
 64              if token.is_eol_or_eof(): 
 65                  break 
 66              nrdtype = dns.rdatatype.from_text(token.value) 
 67              if nrdtype == 0: 
 68                  raise dns.exception.SyntaxError("NSEC with bit 0") 
 69              if nrdtype > 65535: 
 70                  raise dns.exception.SyntaxError("NSEC with bit > 65535") 
 71              rdtypes.append(nrdtype) 
 72          rdtypes.sort() 
 73          window = 0 
 74          octets = 0 
 75          prior_rdtype = 0 
 76          bitmap = bytearray(b'\0' * 32) 
 77          windows = [] 
 78          for nrdtype in rdtypes: 
 79              if nrdtype == prior_rdtype: 
 80                  continue 
 81              prior_rdtype = nrdtype 
 82              new_window = nrdtype // 256 
 83              if new_window != window: 
 84                  windows.append((window, bitmap[0:octets])) 
 85                  bitmap = bytearray(b'\0' * 32) 
 86                  window = new_window 
 87              offset = nrdtype % 256 
 88              byte = offset // 8 
 89              bit = offset % 8 
 90              octets = byte + 1 
 91              bitmap[byte] = bitmap[byte] | (0x80 >> bit) 
 92   
 93          windows.append((window, bitmap[0:octets])) 
 94          return cls(rdclass, rdtype, next, windows) 
 95   
 96 -    def to_wire(self, file, compress=None, origin=None): 
 97          self.next.to_wire(file, None, origin) 
 98          for (window, bitmap) in self.windows: 
 99              file.write(struct.pack('!BB', window, len(bitmap))) 
100              file.write(bitmap) 
101   
102      @classmethod 
103 -    def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin=None): 
104          (next, cused) = dns.name.from_wire(wire[: current + rdlen], current) 
105          current += cused 
106          rdlen -= cused 
107          windows = [] 
108          while rdlen > 0: 
109              if rdlen < 3: 
110                  raise dns.exception.FormError("NSEC too short") 
111              window = wire[current] 
112              octets = wire[current + 1] 
113              if octets == 0 or octets > 32: 
114                  raise dns.exception.FormError("bad NSEC octets") 
115              current += 2 
116              rdlen -= 2 
117              if rdlen < octets: 
118                  raise dns.exception.FormError("bad NSEC bitmap length") 
119              bitmap = bytearray(wire[current: current + octets].unwrap()) 
120              current += octets 
121              rdlen -= octets 
122              windows.append((window, bitmap)) 
123          if origin is not None: 
124              next = next.relativize(origin) 
125          return cls(rdclass, rdtype, next, windows) 
126   
127 -    def choose_relativity(self, origin=None, relativize=True): 
128          self.next = self.next.choose_relativity(origin, relativize) 
129