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# Copyright (C) 2003-2007, 2009-2011 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.
"""Generic Internet address helper functions."""
import socket
import dns.ipv4
import dns.ipv6
# We assume that AF_INET is always defined.
AF_INET = socket.AF_INET
# AF_INET6 might not be defined in the socket module, but we need it.
# We'll try to use the socket module's value, and if it doesn't work,
# we'll use our own value.
try:
AF_INET6 = socket.AF_INET6
except AttributeError:
AF_INET6 = 9999
def inet_pton(family, text):
"""Convert the textual form of a network address into its binary form.
@param family: the address family
@type family: int
@param text: the textual address
@type text: string
@raises NotImplementedError: the address family specified is not
implemented.
@rtype: string
"""
if family == AF_INET:
return dns.ipv4.inet_aton(text)
elif family == AF_INET6:
return dns.ipv6.inet_aton(text)
else:
raise NotImplementedError
def inet_ntop(family, address):
"""Convert the binary form of a network address into its textual form.
@param family: the address family
@type family: int
@param address: the binary address
@type address: string
@raises NotImplementedError: the address family specified is not
implemented.
@rtype: string
"""
if family == AF_INET:
return dns.ipv4.inet_ntoa(address)
elif family == AF_INET6:
return dns.ipv6.inet_ntoa(address)
else:
raise NotImplementedError
def af_for_address(text):
"""Determine the address family of a textual-form network address.
@param text: the textual address
@type text: string
@raises ValueError: the address family cannot be determined from the input.
@rtype: int
"""
try:
dns.ipv4.inet_aton(text)
return AF_INET
except Exception:
try:
dns.ipv6.inet_aton(text)
return AF_INET6
except:
raise ValueError
def is_multicast(text):
"""Is the textual-form network address a multicast address?
@param text: the textual address
@raises ValueError: the address family cannot be determined from the input.
@rtype: bool
"""
try:
first = ord(dns.ipv4.inet_aton(text)[0])
return first >= 224 and first <= 239
except Exception:
try:
first = ord(dns.ipv6.inet_aton(text)[0])
return first == 255
except Exception:
raise ValueError
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