Source Code for Module dns.rdtypes.ANY.NSEC

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  2  # 
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 15   
 16  import struct 
 17   
 18  import dns.exception 
 19  import dns.rdata 
 20  import dns.rdatatype 
 21  import dns.name 
 22  from dns._compat import xrange 
 23   
 24   
 25 -class NSEC(dns.rdata.Rdata): 
 26   
 27      """NSEC record 
 28   
 29      @ivar next: the next name 
 30      @type next: dns.name.Name object 
 31      @ivar windows: the windowed bitmap list 
 32      @type windows: list of (window number, string) tuples""" 
 33   
 34      __slots__ = ['next', 'windows'] 
 35   
 36 -    def __init__(self, rdclass, rdtype, next, windows): 
 37          super(NSEC, self).__init__(rdclass, rdtype) 
 38          self.next = next 
 39          self.windows = windows 
 40   
 41 -    def to_text(self, origin=None, relativize=True, **kw): 
 42          next = self.next.choose_relativity(origin, relativize) 
 43          text = '' 
 44          for (window, bitmap) in self.windows: 
 45              bits = [] 
 46              for i in xrange(0, len(bitmap)): 
 47                  byte = bitmap[i] 
 48                  for j in xrange(0, 8): 
 49                      if byte & (0x80 >> j): 
 50                          bits.append(dns.rdatatype.to_text(window * 256 + 
 51                                                            i * 8 + j)) 
 52              text += (' ' + ' '.join(bits)) 
 53          return '%s%s' % (next, text) 
 54   
 55      @classmethod 
 56 -    def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True): 
 57          next = tok.get_name() 
 58          next = next.choose_relativity(origin, relativize) 
 59          rdtypes = [] 
 60          while 1: 
 61              token = tok.get().unescape() 
 62              if token.is_eol_or_eof(): 
 63                  break 
 64              nrdtype = dns.rdatatype.from_text(token.value) 
 65              if nrdtype == 0: 
 66                  raise dns.exception.SyntaxError("NSEC with bit 0") 
 67              if nrdtype > 65535: 
 68                  raise dns.exception.SyntaxError("NSEC with bit > 65535") 
 69              rdtypes.append(nrdtype) 
 70          rdtypes.sort() 
 71          window = 0 
 72          octets = 0 
 73          prior_rdtype = 0 
 74          bitmap = bytearray(b'\0' * 32) 
 75          windows = [] 
 76          for nrdtype in rdtypes: 
 77              if nrdtype == prior_rdtype: 
 78                  continue 
 79              prior_rdtype = nrdtype 
 80              new_window = nrdtype // 256 
 81              if new_window != window: 
 82                  windows.append((window, bitmap[0:octets])) 
 83                  bitmap = bytearray(b'\0' * 32) 
 84                  window = new_window 
 85              offset = nrdtype % 256 
 86              byte = offset // 8 
 87              bit = offset % 8 
 88              octets = byte + 1 
 89              bitmap[byte] = bitmap[byte] | (0x80 >> bit) 
 90   
 91          windows.append((window, bitmap[0:octets])) 
 92          return cls(rdclass, rdtype, next, windows) 
 93   
 94 -    def to_wire(self, file, compress=None, origin=None): 
 95          self.next.to_wire(file, None, origin) 
 96          for (window, bitmap) in self.windows: 
 97              file.write(struct.pack('!BB', window, len(bitmap))) 
 98              file.write(bitmap) 
 99   
100      @classmethod 
101 -    def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin=None): 
102          (next, cused) = dns.name.from_wire(wire[: current + rdlen], current) 
103          current += cused 
104          rdlen -= cused 
105          windows = [] 
106          while rdlen > 0: 
107              if rdlen < 3: 
108                  raise dns.exception.FormError("NSEC too short") 
109              window = wire[current] 
110              octets = wire[current + 1] 
111              if octets == 0 or octets > 32: 
112                  raise dns.exception.FormError("bad NSEC octets") 
113              current += 2 
114              rdlen -= 2 
115              if rdlen < octets: 
116                  raise dns.exception.FormError("bad NSEC bitmap length") 
117              bitmap = bytearray(wire[current: current + octets].unwrap()) 
118              current += octets 
119              rdlen -= octets 
120              windows.append((window, bitmap)) 
121          if origin is not None: 
122              next = next.relativize(origin) 
123          return cls(rdclass, rdtype, next, windows) 
124   
125 -    def choose_relativity(self, origin=None, relativize=True): 
126          self.next = self.next.choose_relativity(origin, relativize) 
127