191 lines
6.5 KiB
Python
191 lines
6.5 KiB
Python
# meid.py - functions for handling Mobile Equipment Identifiers (MEIDs)
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#
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# Copyright (C) 2010, 2011, 2012, 2013 Arthur de Jong
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#
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# This library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this library; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301 USA
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"""MEID (Mobile Equipment Identifier).
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The Mobile Equipment Identifier is used to identify a physical piece of
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CDMA mobile station equipment.
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>>> validate('AF 01 23 45 0A BC DE C')
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'AF0123450ABCDE'
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>>> validate('29360 87365 0070 3710 0')
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'AF0123450ABCDE'
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>>> validate('29360 87365 0070 3710 0', strip_check_digit=False)
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'AF0123450ABCDEC'
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>>> validate('29360 87365 0070 3710 1')
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Traceback (most recent call last):
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...
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InvalidChecksum: ...
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>>> format('af0123450abcDEC', add_check_digit=True)
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'AF 01 23 45 0A BC DE C'
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>>> format('af0123450abcDEC', format='dec', add_check_digit=True)
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'29360 87365 0070 3710 0'
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"""
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from stdnum.exceptions import *
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from stdnum.util import clean
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_hex_alphabet = '0123456789ABCDEF'
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def _cleanup(number):
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"""Remove any grouping information from the number and removes surrounding
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whitespace."""
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return clean(str(number), ' -').strip().upper()
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def _ishex(number):
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for x in number:
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if x not in _hex_alphabet:
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return False
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return True
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def _parse(number):
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number = _cleanup(number)
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if len(number) in (14, 15):
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# 14 or 15 digit hex representation
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if not _ishex(number):
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raise InvalidFormat()
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return number[0:14], number[14:]
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elif len(number) in (18, 19):
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# 18-digit decimal representation
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if not number.isdigit():
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raise InvalidFormat()
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return number[0:18], number[18:]
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else:
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raise InvalidLength()
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def calc_check_digit(number):
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"""Calculate the check digit for the number. The number should not
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already have a check digit."""
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# both the 18-digit decimal format and the 14-digit hex format
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# containing only decimal digits should use the decimal Luhn check
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from stdnum import luhn
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if number.isdigit():
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return luhn.calc_check_digit(number)
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else:
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return luhn.calc_check_digit(number, alphabet=_hex_alphabet)
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def compact(number, strip_check_digit=True):
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"""Convert the MEID number to the minimal (hexadecimal) representation.
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This strips grouping information, removes surrounding whitespace and
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converts to hexadecimal if needed. If the check digit is to be preserved
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and conversion is done a new check digit is recalculated."""
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# first parse the number
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number, cd = _parse(number)
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# strip check digit if needed
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if strip_check_digit:
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cd = ''
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# convert to hex if needed
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if len(number) == 18:
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number = '%08X%06X' % (int(number[0:10]), int(number[10:18]))
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if cd:
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cd = calc_check_digit(number)
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# put parts back together again
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return number + cd
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def validate(number, strip_check_digit=True):
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"""Checks to see if the number provided is a valid MEID number. This
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converts the representation format of the number (if it is
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decimal it is not converted to hexadecimal)."""
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from stdnum import luhn
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# first parse the number
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number, cd = _parse(number)
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if len(number) == 18:
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# decimal format can be easily determined
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if cd:
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luhn.validate(number + cd)
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# convert to hex
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manufacturer_code = int(number[0:10])
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serial_num = int(number[10:18])
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if manufacturer_code.bit_length() > 32 or serial_num.bit_length() > 24:
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raise InvalidComponent()
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number = '%08X%06X' % (manufacturer_code, serial_num)
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cd = calc_check_digit(number)
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elif number.isdigit():
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# if the remaining hex format is fully decimal it is an IMEI number
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from stdnum import imei
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imei.validate(number + cd)
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else:
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# normal hex Luhn validation
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if cd:
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luhn.validate(number + cd, alphabet=_hex_alphabet)
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if strip_check_digit:
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cd = ''
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return number + cd
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def is_valid(number):
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"""Checks to see if the number provided is a valid MEID number."""
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try:
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return bool(validate(number))
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except ValidationError:
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return False
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def format(number, separator=' ', format=None, add_check_digit=False):
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"""Reformat the passed number to the standard format. The separator
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used can be provided. If the format is specified (either 'hex' or
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'dec') the number is reformatted in that format, otherwise the current
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representation is kept. If add_check_digit is True a check digit will
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be added if it is not present yet."""
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# first parse the number
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number, cd = _parse(number)
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# format conversions if needed
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if format == 'dec' and len(number) == 14:
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# convert to decimal
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number = '%010d%08d' % (int(number[0:8], 16), int(number[8:14], 16))
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if cd:
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cd = calc_check_digit(number)
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elif format == 'hex' and len(number) == 18:
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# convert to hex
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number = '%08X%06X' % (int(number[0:10]), int(number[10:18]))
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if cd:
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cd = calc_check_digit(number)
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# see if we need to add a check digit
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if add_check_digit and not cd:
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cd = calc_check_digit(number)
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# split number according to format
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if len(number) == 14:
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number = [number[i * 2:i * 2 + 2]
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for i in range(7)] + [cd]
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else:
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number = (number[:5], number[5:10], number[10:14], number[14:], cd)
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return separator.join(x for x in number if x)
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def to_binary(number):
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"""Convert the number to its binary representation (without the check
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digit)."""
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from binascii import a2b_hex
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return a2b_hex(compact(number, strip_check_digit=True))
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def to_pseudo_esn(number):
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"""Convert the provided MEID to a pseudo ESN (pESN). The ESN is returned
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in compact hexadecimal representation."""
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import hashlib
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# return the last 6 digits of the SHA1 hash prefixed with the reserved
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# manufacturer code
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return '80' + hashlib.sha1(to_binary(number)).hexdigest()[-6:].upper()
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