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# Copyright (C) 2006, 2007, 2009, 2010 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.
@var ipv4_reverse_domain: The DNS IPv4 reverse-map domain, in-addr.arpa.
@type ipv4_reverse_domain: dns.name.Name object
@var ipv6_reverse_domain: The DNS IPv6 reverse-map domain, ip6.arpa.
@type ipv6_reverse_domain: dns.name.Name object
"""
import dns.name
import dns.ipv6
import dns.ipv4
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.
@param text: an IPv4 or IPv6 address in textual form (e.g. '127.0.0.1',
'::1')
@type text: str
@rtype: dns.name.Name object
"""
try:
parts = list(dns.ipv6.inet_aton(text).encode('hex_codec'))
origin = ipv6_reverse_domain
except:
parts = ['%d' % ord(byte) for byte in 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.
@param name: an IPv4 or IPv6 address in reverse-map form.
@type name: dns.name.Name object
@rtype: str
"""
if name.is_subdomain(ipv4_reverse_domain):
name = name.relativize(ipv4_reverse_domain)
labels = list(name.labels)
labels.reverse()
text = '.'.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(''.join(labels[i:i+4]))
i += 4
text = ':'.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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