Package dns :: Package rdtypes :: Package IN :: Module APL
[hide private]
[frames] | no frames]

Source Code for Module dns.rdtypes.IN.APL

  1  # Copyright (C) 2003-2007, 2009 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  import cStringIO 
 17  import struct 
 18   
 19  import dns.exception 
 20  import dns.inet 
 21  import dns.rdata 
 22  import dns.tokenizer 
 23   
24 -class APLItem(object):
25 """An APL list item. 26 27 @ivar family: the address family (IANA address family registry) 28 @type family: int 29 @ivar negation: is this item negated? 30 @type negation: bool 31 @ivar address: the address 32 @type address: string 33 @ivar prefix: the prefix length 34 @type prefix: int 35 """ 36 37 __slots__ = ['family', 'negation', 'address', 'prefix'] 38
39 - def __init__(self, family, negation, address, prefix):
40 self.family = family 41 self.negation = negation 42 self.address = address 43 self.prefix = prefix
44
45 - def __str__(self):
46 if self.negation: 47 return "!%d:%s/%s" % (self.family, self.address, self.prefix) 48 else: 49 return "%d:%s/%s" % (self.family, self.address, self.prefix)
50
51 - def to_wire(self, file):
52 if self.family == 1: 53 address = dns.inet.inet_pton(dns.inet.AF_INET, self.address) 54 elif self.family == 2: 55 address = dns.inet.inet_pton(dns.inet.AF_INET6, self.address) 56 else: 57 address = self.address.decode('hex_codec') 58 # 59 # Truncate least significant zero bytes. 60 # 61 last = 0 62 for i in xrange(len(address) - 1, -1, -1): 63 if address[i] != chr(0): 64 last = i + 1 65 break 66 address = address[0 : last] 67 l = len(address) 68 assert l < 128 69 if self.negation: 70 l |= 0x80 71 header = struct.pack('!HBB', self.family, self.prefix, l) 72 file.write(header) 73 file.write(address)
74
75 -class APL(dns.rdata.Rdata):
76 """APL record. 77 78 @ivar items: a list of APL items 79 @type items: list of APL_Item 80 @see: RFC 3123""" 81 82 __slots__ = ['items'] 83
84 - def __init__(self, rdclass, rdtype, items):
85 super(APL, self).__init__(rdclass, rdtype) 86 self.items = items
87
88 - def to_text(self, origin=None, relativize=True, **kw):
89 return ' '.join(map(lambda x: str(x), self.items))
90
91 - def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True):
92 items = [] 93 while 1: 94 (ttype, item) = tok.get() 95 if ttype == dns.tokenizer.EOL or ttype == dns.tokenizer.EOF: 96 break 97 if item[0] == '!': 98 negation = True 99 item = item[1:] 100 else: 101 negation = False 102 (family, rest) = item.split(':', 1) 103 family = int(family) 104 (address, prefix) = rest.split('/', 1) 105 prefix = int(prefix) 106 item = APLItem(family, negation, address, prefix) 107 items.append(item) 108 109 return cls(rdclass, rdtype, items)
110 111 from_text = classmethod(from_text) 112
113 - def to_wire(self, file, compress = None, origin = None):
114 for item in self.items: 115 item.to_wire(file)
116
117 - def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None):
118 items = [] 119 while 1: 120 if rdlen < 4: 121 raise dns.exception.FormError 122 header = struct.unpack('!HBB', wire[current : current + 4]) 123 afdlen = header[2] 124 if afdlen > 127: 125 negation = True 126 afdlen -= 128 127 else: 128 negation = False 129 current += 4 130 rdlen -= 4 131 if rdlen < afdlen: 132 raise dns.exception.FormError 133 address = wire[current : current + afdlen] 134 l = len(address) 135 if header[0] == 1: 136 if l < 4: 137 address += '\x00' * (4 - l) 138 address = dns.inet.inet_ntop(dns.inet.AF_INET, address) 139 elif header[0] == 2: 140 if l < 16: 141 address += '\x00' * (16 - l) 142 address = dns.inet.inet_ntop(dns.inet.AF_INET6, address) 143 else: 144 # 145 # This isn't really right according to the RFC, but it 146 # seems better than throwing an exception 147 # 148 address = address.encode('hex_codec') 149 current += afdlen 150 rdlen -= afdlen 151 item = APLItem(header[0], negation, address, header[1]) 152 items.append(item) 153 if rdlen == 0: 154 break 155 return cls(rdclass, rdtype, items)
156 157 from_wire = classmethod(from_wire) 158
159 - def _cmp(self, other):
160 f = cStringIO.StringIO() 161 self.to_wire(f) 162 wire1 = f.getvalue() 163 f.seek(0) 164 f.truncate() 165 other.to_wire(f) 166 wire2 = f.getvalue() 167 f.close() 168 169 return cmp(wire1, wire2)
170