# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
# Copyright (C) 2006-2017 Nominum, Inc.
#
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# provided that the above copyright notice and this permission notice
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# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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"""DNS Reverse Map Names."""
import binascii
import dns.ipv4
import dns.ipv6
import dns.name
ipv4_reverse_domain = dns.name.from_text("in-addr.arpa.")
ipv6_reverse_domain = dns.name.from_text("ip6.arpa.")
def from_address(
text: str,
v4_origin: dns.name.Name = ipv4_reverse_domain,
v6_origin: dns.name.Name = ipv6_reverse_domain,
) -> dns.name.Name:
"""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 ``str``, is an IPv4 or IPv6 address in textual form
(e.g. '127.0.0.1', '::1')
*v4_origin*, a ``dns.name.Name`` to append to the labels corresponding to
the address if the address is an IPv4 address, instead of the default
(in-addr.arpa.)
*v6_origin*, a ``dns.name.Name`` to append to the labels corresponding to
the address if the address is an IPv6 address, instead of the default
(ip6.arpa.)
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):
parts = ["%d" % byte for byte in v6[12:]]
origin = v4_origin
else:
parts = [x for x in str(binascii.hexlify(v6).decode())]
origin = v6_origin
except Exception:
parts = ["%d" % byte for byte in dns.ipv4.inet_aton(text)]
origin = v4_origin
return dns.name.from_text(".".join(reversed(parts)), origin=origin)
def to_address(
name: dns.name.Name,
v4_origin: dns.name.Name = ipv4_reverse_domain,
v6_origin: dns.name.Name = ipv6_reverse_domain,
) -> str:
"""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.
*v4_origin*, a ``dns.name.Name`` representing the top-level domain for
IPv4 addresses, instead of the default (in-addr.arpa.)
*v6_origin*, a ``dns.name.Name`` representing the top-level domain for
IPv4 addresses, instead of the default (ip6.arpa.)
Raises ``dns.exception.SyntaxError`` if the name does not have a
reverse-map form.
Returns a ``str``.
"""
if name.is_subdomain(v4_origin):
name = name.relativize(v4_origin)
text = b".".join(reversed(name.labels))
# run through inet_ntoa() to check syntax and make pretty.
return dns.ipv4.inet_ntoa(dns.ipv4.inet_aton(text))
elif name.is_subdomain(v6_origin):
name = name.relativize(v6_origin)
labels = list(reversed(name.labels))
parts = []
for i in range(0, len(labels), 4):
parts.append(b"".join(labels[i : i + 4]))
text = b":".join(parts)
# run through inet_ntoa() 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")
