Source Code for Module dns.inet

  1  # Copyright (C) 2003-2007, 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  """Generic Internet address helper functions.""" 
 17   
 18  import socket 
 19   
 20  import dns.ipv4 
 21  import dns.ipv6 
 22   
 23   
 24  # We assume that AF_INET is always defined. 
 25   
 26  AF_INET = socket.AF_INET 
 27   
 28  # AF_INET6 might not be defined in the socket module, but we need it. 
 29  # We'll try to use the socket module's value, and if it doesn't work, 
 30  # we'll use our own value. 
 31   
 32  try: 
 33      AF_INET6 = socket.AF_INET6 
 34  except AttributeError: 
 35      AF_INET6 = 9999 
 36   
 37   
 38 -def inet_pton(family, text): 
 39      """Convert the textual form of a network address into its binary form. 
 40   
 41      @param family: the address family 
 42      @type family: int 
 43      @param text: the textual address 
 44      @type text: string 
 45      @raises NotImplementedError: the address family specified is not 
 46      implemented. 
 47      @rtype: string 
 48      """ 
 49   
 50      if family == AF_INET: 
 51          return dns.ipv4.inet_aton(text) 
 52      elif family == AF_INET6: 
 53          return dns.ipv6.inet_aton(text) 
 54      else: 
 55          raise NotImplementedError 
 56   
 57   
 58 -def inet_ntop(family, address): 
 59      """Convert the binary form of a network address into its textual form. 
 60   
 61      @param family: the address family 
 62      @type family: int 
 63      @param address: the binary address 
 64      @type address: string 
 65      @raises NotImplementedError: the address family specified is not 
 66      implemented. 
 67      @rtype: string 
 68      """ 
 69      if family == AF_INET: 
 70          return dns.ipv4.inet_ntoa(address) 
 71      elif family == AF_INET6: 
 72          return dns.ipv6.inet_ntoa(address) 
 73      else: 
 74          raise NotImplementedError 
 75   
 76   
 77 -def af_for_address(text): 
 78      """Determine the address family of a textual-form network address. 
 79   
 80      @param text: the textual address 
 81      @type text: string 
 82      @raises ValueError: the address family cannot be determined from the input. 
 83      @rtype: int 
 84      """ 
 85      try: 
 86          dns.ipv4.inet_aton(text) 
 87          return AF_INET 
 88      except: 
 89          try: 
 90              dns.ipv6.inet_aton(text) 
 91              return AF_INET6 
 92          except: 
 93              raise ValueError 
 94   
 95   
 96 -def is_multicast(text): 
 97      """Is the textual-form network address a multicast address? 
 98   
 99      @param text: the textual address 
100      @raises ValueError: the address family cannot be determined from the input. 
101      @rtype: bool 
102      """ 
103      try: 
104          first = ord(dns.ipv4.inet_aton(text)[0]) 
105          return (first >= 224 and first <= 239) 
106      except: 
107          try: 
108              first = ord(dns.ipv6.inet_aton(text)[0]) 
109              return (first == 255) 
110          except: 
111              raise ValueError 
112