Source Code for Module dns.reversename

 1  # Copyright (C) 2006, 2007, 2009-2011 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  """DNS Reverse Map Names. 
17   
18  @var ipv4_reverse_domain: The DNS IPv4 reverse-map domain, in-addr.arpa. 
19  @type ipv4_reverse_domain: dns.name.Name object 
20  @var ipv6_reverse_domain: The DNS IPv6 reverse-map domain, ip6.arpa. 
21  @type ipv6_reverse_domain: dns.name.Name object 
22  """ 
23   
24  import binascii 
25  import sys 
26   
27  import dns.name 
28  import dns.ipv6 
29  import dns.ipv4 
30   
31  ipv4_reverse_domain = dns.name.from_text('in-addr.arpa.') 
32  ipv6_reverse_domain = dns.name.from_text('ip6.arpa.') 
33   
34   
35 -def from_address(text): 
36      """Convert an IPv4 or IPv6 address in textual form into a Name object whose 
37      value is the reverse-map domain name of the address. 
38      @param text: an IPv4 or IPv6 address in textual form (e.g. '127.0.0.1', 
39      '::1') 
40      @type text: str 
41      @rtype: dns.name.Name object 
42      """ 
43      try: 
44          v6 = dns.ipv6.inet_aton(text) 
45          if dns.ipv6.is_mapped(v6): 
46              if sys.version_info >= (3,): 
47                  parts = ['%d' % byte for byte in v6[12:]] 
48              else: 
49                  parts = ['%d' % ord(byte) for byte in v6[12:]] 
50              origin = ipv4_reverse_domain 
51          else: 
52              parts = [x for x in str(binascii.hexlify(v6).decode())] 
53              origin = ipv6_reverse_domain 
54      except Exception: 
55          parts = ['%d' % 
56                   byte for byte in bytearray(dns.ipv4.inet_aton(text))] 
57          origin = ipv4_reverse_domain 
58      parts.reverse() 
59      return dns.name.from_text('.'.join(parts), origin=origin) 
60   
61   
62 -def to_address(name): 
63      """Convert a reverse map domain name into textual address form. 
64      @param name: an IPv4 or IPv6 address in reverse-map form. 
65      @type name: dns.name.Name object 
66      @rtype: str 
67      """ 
68      if name.is_subdomain(ipv4_reverse_domain): 
69          name = name.relativize(ipv4_reverse_domain) 
70          labels = list(name.labels) 
71          labels.reverse() 
72          text = b'.'.join(labels) 
73          # run through inet_aton() to check syntax and make pretty. 
74          return dns.ipv4.inet_ntoa(dns.ipv4.inet_aton(text)) 
75      elif name.is_subdomain(ipv6_reverse_domain): 
76          name = name.relativize(ipv6_reverse_domain) 
77          labels = list(name.labels) 
78          labels.reverse() 
79          parts = [] 
80          i = 0 
81          l = len(labels) 
82          while i < l: 
83              parts.append(b''.join(labels[i:i + 4])) 
84              i += 4 
85          text = b':'.join(parts) 
86          # run through inet_aton() to check syntax and make pretty. 
87          return dns.ipv6.inet_ntoa(dns.ipv6.inet_aton(text)) 
88      else: 
89          raise dns.exception.SyntaxError('unknown reverse-map address family') 
90