# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
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# Copyright (C) 2006-2017 Nominum, Inc.
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#
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# Permission to use, copy, modify, and distribute this software and its
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# documentation for any purpose with or without fee is hereby granted,
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# provided that the above copyright notice and this permission notice
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# appear in all copies.
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#
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# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
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# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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"""DNS Reverse Map Names."""
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import binascii
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import dns.name
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import dns.ipv6
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import dns.ipv4
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from dns._compat import PY3
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ipv4_reverse_domain = dns.name.from_text('in-addr.arpa.')
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ipv6_reverse_domain = dns.name.from_text('ip6.arpa.')
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def from_address(text):
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"""Convert an IPv4 or IPv6 address in textual form into a Name object whose
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value is the reverse-map domain name of the address.
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*text*, a ``text``, is an IPv4 or IPv6 address in textual form
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(e.g. '127.0.0.1', '::1')
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Raises ``dns.exception.SyntaxError`` if the address is badly formed.
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Returns a ``dns.name.Name``.
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"""
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try:
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v6 = dns.ipv6.inet_aton(text)
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if dns.ipv6.is_mapped(v6):
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if PY3:
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parts = ['%d' % byte for byte in v6[12:]]
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else:
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parts = ['%d' % ord(byte) for byte in v6[12:]]
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origin = ipv4_reverse_domain
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else:
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parts = [x for x in str(binascii.hexlify(v6).decode())]
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origin = ipv6_reverse_domain
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except Exception:
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parts = ['%d' %
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byte for byte in bytearray(dns.ipv4.inet_aton(text))]
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origin = ipv4_reverse_domain
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parts.reverse()
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return dns.name.from_text('.'.join(parts), origin=origin)
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def to_address(name):
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"""Convert a reverse map domain name into textual address form.
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*name*, a ``dns.name.Name``, an IPv4 or IPv6 address in reverse-map name
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form.
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Raises ``dns.exception.SyntaxError`` if the name does not have a
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reverse-map form.
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Returns a ``text``.
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"""
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if name.is_subdomain(ipv4_reverse_domain):
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name = name.relativize(ipv4_reverse_domain)
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labels = list(name.labels)
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labels.reverse()
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text = b'.'.join(labels)
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# run through inet_aton() to check syntax and make pretty.
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return dns.ipv4.inet_ntoa(dns.ipv4.inet_aton(text))
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elif name.is_subdomain(ipv6_reverse_domain):
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name = name.relativize(ipv6_reverse_domain)
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labels = list(name.labels)
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labels.reverse()
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parts = []
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i = 0
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l = len(labels)
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while i < l:
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parts.append(b''.join(labels[i:i + 4]))
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i += 4
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text = b':'.join(parts)
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# run through inet_aton() to check syntax and make pretty.
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return dns.ipv6.inet_ntoa(dns.ipv6.inet_aton(text))
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else:
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raise dns.exception.SyntaxError('unknown reverse-map address family')
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