Source Code for Module dns.ipv4

 1  # Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license 
 2   
 3  # Copyright (C) 2003-2017 Nominum, Inc. 
 4  # 
 5  # Permission to use, copy, modify, and distribute this software and its 
 6  # documentation for any purpose with or without fee is hereby granted, 
 7  # provided that the above copyright notice and this permission notice 
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10  # THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES 
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16  # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 
17   
18  """IPv4 helper functions.""" 
19   
20  import struct 
21   
22  import dns.exception 
23  from ._compat import binary_type 
24   
25 -def inet_ntoa(address): 
26      """Convert an IPv4 address in binary form to text form. 
27   
28      *address*, a ``binary``, the IPv4 address in binary form. 
29   
30      Returns a ``text``. 
31      """ 
32   
33      if len(address) != 4: 
34          raise dns.exception.SyntaxError 
35      if not isinstance(address, bytearray): 
36          address = bytearray(address) 
37      return ('%u.%u.%u.%u' % (address[0], address[1], 
38                               address[2], address[3])) 
39   
40 -def inet_aton(text): 
41      """Convert an IPv4 address in text form to binary form. 
42   
43      *text*, a ``text``, the IPv4 address in textual form. 
44   
45      Returns a ``binary``. 
46      """ 
47   
48      if not isinstance(text, binary_type): 
49          text = text.encode() 
50      parts = text.split(b'.') 
51      if len(parts) != 4: 
52          raise dns.exception.SyntaxError 
53      for part in parts: 
54          if not part.isdigit(): 
55              raise dns.exception.SyntaxError 
56          if len(part) > 1 and part[0] == '0': 
57              # No leading zeros 
58              raise dns.exception.SyntaxError 
59      try: 
60          bytes = [int(part) for part in parts] 
61          return struct.pack('BBBB', *bytes) 
62      except: 
63          raise dns.exception.SyntaxError 
64