1 # Copyright (C) 2006, 2007, 2009, 2010 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 dns.name 25 import dns.ipv6 26 import dns.ipv4 27 28 ipv4_reverse_domain = dns.name.from_text('in-addr.arpa.') 29 ipv6_reverse_domain = dns.name.from_text('ip6.arpa.') 30 31 def from_address(text): 32 """Convert an IPv4 or IPv6 address in textual form into a Name object whose 33 value is the reverse-map domain name of the address. 34 @param text: an IPv4 or IPv6 address in textual form (e.g. '127.0.0.1', 35 '::1') 36 @type text: str 37 @rtype: dns.name.Name object 38 """ 39 try: 40 parts = list(dns.ipv6.inet_aton(text).encode('hex_codec')) 41 origin = ipv6_reverse_domain 42 except: 43 parts = ['%d' % ord(byte) for byte in dns.ipv4.inet_aton(text)] 44 origin = ipv4_reverse_domain 45 parts.reverse() 46 return dns.name.from_text('.'.join(parts), origin=origin) 47 48 def to_address(name): 49 """Convert a reverse map domain name into textual address form. 50 @param name: an IPv4 or IPv6 address in reverse-map form. 51 @type name: dns.name.Name object 52 @rtype: str 53 """ 54 if name.is_subdomain(ipv4_reverse_domain): 55 name = name.relativize(ipv4_reverse_domain) 56 labels = list(name.labels) 57 labels.reverse() 58 text = '.'.join(labels) 59 # run through inet_aton() to check syntax and make pretty. 60 return dns.ipv4.inet_ntoa(dns.ipv4.inet_aton(text)) 61 elif name.is_subdomain(ipv6_reverse_domain): 62 name = name.relativize(ipv6_reverse_domain) 63 labels = list(name.labels) 64 labels.reverse() 65 parts = [] 66 i = 0 67 l = len(labels) 68 while i < l: 69 parts.append(''.join(labels[i:i+4])) 70 i += 4 71 text = ':'.join(parts) 72 # run through inet_aton() to check syntax and make pretty. 73 return dns.ipv6.inet_ntoa(dns.ipv6.inet_aton(text)) 74 else: 75 raise dns.exception.SyntaxError('unknown reverse-map address family') 76