106 lines
3.7 KiB
Python
106 lines
3.7 KiB
Python
# 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.ipv4
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import dns.ipv6
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import dns.name
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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(
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text: str,
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v4_origin: dns.name.Name = ipv4_reverse_domain,
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v6_origin: dns.name.Name = ipv6_reverse_domain,
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) -> dns.name.Name:
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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 ``str``, is an IPv4 or IPv6 address in textual form
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(e.g. '127.0.0.1', '::1')
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*v4_origin*, a ``dns.name.Name`` to append to the labels corresponding to
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the address if the address is an IPv4 address, instead of the default
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(in-addr.arpa.)
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*v6_origin*, a ``dns.name.Name`` to append to the labels corresponding to
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the address if the address is an IPv6 address, instead of the default
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(ip6.arpa.)
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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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parts = ["%d" % byte for byte in v6[12:]]
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origin = v4_origin
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else:
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parts = [x for x in str(binascii.hexlify(v6).decode())]
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origin = v6_origin
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except Exception:
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parts = ["%d" % byte for byte in dns.ipv4.inet_aton(text)]
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origin = v4_origin
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return dns.name.from_text(".".join(reversed(parts)), origin=origin)
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def to_address(
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name: dns.name.Name,
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v4_origin: dns.name.Name = ipv4_reverse_domain,
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v6_origin: dns.name.Name = ipv6_reverse_domain,
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) -> str:
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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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*v4_origin*, a ``dns.name.Name`` representing the top-level domain for
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IPv4 addresses, instead of the default (in-addr.arpa.)
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*v6_origin*, a ``dns.name.Name`` representing the top-level domain for
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IPv4 addresses, instead of the default (ip6.arpa.)
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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 ``str``.
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"""
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if name.is_subdomain(v4_origin):
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name = name.relativize(v4_origin)
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text = b".".join(reversed(name.labels))
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# run through inet_ntoa() 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(v6_origin):
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name = name.relativize(v6_origin)
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labels = list(reversed(name.labels))
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parts = []
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for i in range(0, len(labels), 4):
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parts.append(b"".join(labels[i : i + 4]))
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text = b":".join(parts)
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# run through inet_ntoa() 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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