Source Code for Module dns.inet

  1  # Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license 
  2   
  3  # Copyright (C) 2003-2017 Nominum, Inc. 
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 17   
 18  """Generic Internet address helper functions.""" 
 19   
 20  import socket 
 21   
 22  import dns.ipv4 
 23  import dns.ipv6 
 24   
 25  from ._compat import maybe_ord 
 26   
 27  # We assume that AF_INET is always defined. 
 28   
 29  AF_INET = socket.AF_INET 
 30   
 31  # AF_INET6 might not be defined in the socket module, but we need it. 
 32  # We'll try to use the socket module's value, and if it doesn't work, 
 33  # we'll use our own value. 
 34   
 35  try: 
 36      AF_INET6 = socket.AF_INET6 
 37  except AttributeError: 
 38      AF_INET6 = 9999 
 39   
 40   
 41 -def inet_pton(family, text): 
 42      """Convert the textual form of a network address into its binary form. 
 43   
 44      *family* is an ``int``, the address family. 
 45   
 46      *text* is a ``text``, the textual address. 
 47   
 48      Raises ``NotImplementedError`` if the address family specified is not 
 49      implemented. 
 50   
 51      Returns a ``binary``. 
 52      """ 
 53   
 54      if family == AF_INET: 
 55          return dns.ipv4.inet_aton(text) 
 56      elif family == AF_INET6: 
 57          return dns.ipv6.inet_aton(text) 
 58      else: 
 59          raise NotImplementedError 
 60   
 61   
 62 -def inet_ntop(family, address): 
 63      """Convert the binary form of a network address into its textual form. 
 64   
 65      *family* is an ``int``, the address family. 
 66   
 67      *address* is a ``binary``, the network address in binary form. 
 68   
 69      Raises ``NotImplementedError`` if the address family specified is not 
 70      implemented. 
 71   
 72      Returns a ``text``. 
 73      """ 
 74   
 75      if family == AF_INET: 
 76          return dns.ipv4.inet_ntoa(address) 
 77      elif family == AF_INET6: 
 78          return dns.ipv6.inet_ntoa(address) 
 79      else: 
 80          raise NotImplementedError 
 81   
 82   
 83 -def af_for_address(text): 
 84      """Determine the address family of a textual-form network address. 
 85   
 86      *text*, a ``text``, the textual address. 
 87   
 88      Raises ``ValueError`` if the address family cannot be determined 
 89      from the input. 
 90   
 91      Returns an ``int``. 
 92      """ 
 93   
 94      try: 
 95          dns.ipv4.inet_aton(text) 
 96          return AF_INET 
 97      except Exception: 
 98          try: 
 99              dns.ipv6.inet_aton(text) 
100              return AF_INET6 
101          except: 
102              raise ValueError 
103   
104   
105 -def is_multicast(text): 
106      """Is the textual-form network address a multicast address? 
107   
108      *text*, a ``text``, the textual address. 
109   
110      Raises ``ValueError`` if the address family cannot be determined 
111      from the input. 
112   
113      Returns a ``bool``. 
114      """ 
115   
116      try: 
117          first = maybe_ord(dns.ipv4.inet_aton(text)[0]) 
118          return first >= 224 and first <= 239 
119      except Exception: 
120          try: 
121              first = maybe_ord(dns.ipv6.inet_aton(text)[0]) 
122              return first == 255 
123          except Exception: 
124              raise ValueError 
125