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