| 1 | # Copyright (C) 2006, 2007, 2009, 2010 Nominum, Inc.
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| 2 | #
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| 3 | # Permission to use, copy, modify, and distribute this software and its
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| 4 | # documentation for any purpose with or without fee is hereby granted,
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| 5 | # provided that the above copyright notice and this permission notice
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| 6 | # appear in all copies.
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| 7 | #
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| 8 | # THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
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| 9 | # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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| 10 | # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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| 11 | # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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| 12 | # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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| 13 | # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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| 14 | # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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| 15 |
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| 16 | """DNS Reverse Map Names.
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| 17 |
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| 18 | @var ipv4_reverse_domain: The DNS IPv4 reverse-map domain, in-addr.arpa.
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| 19 | @type ipv4_reverse_domain: dns.name.Name object
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| 20 | @var ipv6_reverse_domain: The DNS IPv6 reverse-map domain, ip6.arpa.
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| 21 | @type ipv6_reverse_domain: dns.name.Name object
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| 22 | """
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| 23 |
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| 24 | import dns.name
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| 25 | import dns.ipv6
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| 26 | import dns.ipv4
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| 27 |
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| 28 | ipv4_reverse_domain = dns.name.from_text('in-addr.arpa.')
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| 29 | ipv6_reverse_domain = dns.name.from_text('ip6.arpa.')
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| 30 |
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| 31 | def from_address(text):
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| 32 | """Convert an IPv4 or IPv6 address in textual form into a Name object whose
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| 33 | value is the reverse-map domain name of the address.
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| 34 | @param text: an IPv4 or IPv6 address in textual form (e.g. '127.0.0.1',
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| 35 | '::1')
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| 36 | @type text: str
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| 37 | @rtype: dns.name.Name object
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| 38 | """
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| 39 | try:
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| 40 | parts = list(dns.ipv6.inet_aton(text).encode('hex_codec'))
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| 41 | origin = ipv6_reverse_domain
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| 42 | except:
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| 43 | parts = ['%d' % ord(byte) for byte in dns.ipv4.inet_aton(text)]
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| 44 | origin = ipv4_reverse_domain
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| 45 | parts.reverse()
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| 46 | return dns.name.from_text('.'.join(parts), origin=origin)
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| 47 |
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| 48 | def to_address(name):
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| 49 | """Convert a reverse map domain name into textual address form.
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| 50 | @param name: an IPv4 or IPv6 address in reverse-map form.
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| 51 | @type name: dns.name.Name object
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| 52 | @rtype: str
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| 53 | """
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| 54 | if name.is_subdomain(ipv4_reverse_domain):
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| 55 | name = name.relativize(ipv4_reverse_domain)
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| 56 | labels = list(name.labels)
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| 57 | labels.reverse()
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| 58 | text = '.'.join(labels)
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| 59 | # run through inet_aton() to check syntax and make pretty.
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| 60 | return dns.ipv4.inet_ntoa(dns.ipv4.inet_aton(text))
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| 61 | elif name.is_subdomain(ipv6_reverse_domain):
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| 62 | name = name.relativize(ipv6_reverse_domain)
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| 63 | labels = list(name.labels)
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| 64 | labels.reverse()
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| 65 | parts = []
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| 66 | i = 0
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| 67 | l = len(labels)
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| 68 | while i < l:
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| 69 | parts.append(''.join(labels[i:i+4]))
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| 70 | i += 4
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| 71 | text = ':'.join(parts)
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| 72 | # run through inet_aton() to check syntax and make pretty.
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| 73 | return dns.ipv6.inet_ntoa(dns.ipv6.inet_aton(text))
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| 74 | else:
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| 75 | raise dns.exception.SyntaxError('unknown reverse-map address family')
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