57 lines
1.8 KiB
Python
57 lines
1.8 KiB
Python
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#-----------------------------------------------------------------------------
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# Copyright (c) 2008-2012, David P. D. Moss. All rights reserved.
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#
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# Released under the BSD license. See the LICENSE file for details.
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#-----------------------------------------------------------------------------
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"""A basic implementation of RFC 1924 ;-)"""
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from netaddr.core import AddrFormatError
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from netaddr.ip import IPAddress
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from netaddr.compat import _zip
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#-----------------------------------------------------------------------------
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def chr_range(low, high):
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"""Returns all characters between low and high chars."""
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return [chr(i) for i in range(ord(low), ord(high)+1)]
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#: Base 85 integer index to character lookup table.
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BASE_85 = chr_range('0', '9') + chr_range('A', 'Z') + chr_range('a', 'z') + \
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['!', '#', '$', '%', '&', '(',')', '*', '+', '-',';', '<', '=', '>',
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'?', '@', '^', '_','`', '{', '|', '}', '~']
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#: Base 85 digit to integer lookup table.
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BASE_85_DICT = dict(_zip(BASE_85, range(0, 86)))
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#-----------------------------------------------------------------------------
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def ipv6_to_base85(addr):
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"""Convert a regular IPv6 address to base 85."""
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ip = IPAddress(addr)
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int_val = int(ip)
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remainder = []
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while int_val > 0:
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remainder.append(int_val % 85)
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int_val //= 85
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return ''.join([BASE_85[w] for w in reversed(remainder)])
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#-----------------------------------------------------------------------------
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def base85_to_ipv6(addr):
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"""
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Convert a base 85 IPv6 address to its hexadecimal format.
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"""
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tokens = list(addr)
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if len(tokens) != 20:
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raise AddrFormatError('Invalid base 85 IPv6 addess: %r' % addr)
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result = 0
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for i, num in enumerate(reversed(tokens)):
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num = BASE_85_DICT[num]
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result += (num * 85 ** i)
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ip = IPAddress(result, 6)
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return str(ip)
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