284 lines
9.2 KiB
Python
284 lines
9.2 KiB
Python
"""
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Operations with addresses
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"""
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# pylint: disable=inconsistent-return-statements
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import hashlib
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import logging
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from binascii import hexlify, unhexlify
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from struct import pack, unpack
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logger = logging.getLogger('default')
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ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
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def encodeBase58(num):
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"""Encode a number in Base X
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Args:
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num: The number to encode
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alphabet: The alphabet to use for encoding
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"""
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if num < 0:
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return None
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if num == 0:
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return ALPHABET[0]
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arr = []
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base = len(ALPHABET)
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while num:
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num, rem = divmod(num, base)
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arr.append(ALPHABET[rem])
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arr.reverse()
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return ''.join(arr)
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def decodeBase58(string):
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"""Decode a Base X encoded string into the number
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Args:
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string: The encoded string
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alphabet: The alphabet to use for encoding
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"""
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base = len(ALPHABET)
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num = 0
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try:
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for char in string:
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num *= base
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num += ALPHABET.index(char)
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except ValueError:
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# character not found (like a space character or a 0)
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return 0
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return num
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class varintEncodeError(Exception):
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"""Exception class for encoding varint"""
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pass
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class varintDecodeError(Exception):
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"""Exception class for decoding varint data"""
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pass
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def encodeVarint(integer):
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"""Convert integer into varint bytes"""
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if integer < 0:
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raise varintEncodeError('varint cannot be < 0')
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if integer < 253:
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return pack('>B', integer)
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if integer >= 253 and integer < 65536:
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return pack('>B', 253) + pack('>H', integer)
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if integer >= 65536 and integer < 4294967296:
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return pack('>B', 254) + pack('>I', integer)
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if integer >= 4294967296 and integer < 18446744073709551616:
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return pack('>B', 255) + pack('>Q', integer)
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if integer >= 18446744073709551616:
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raise varintEncodeError('varint cannot be >= 18446744073709551616')
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def decodeVarint(data):
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"""
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Decodes an encoded varint to an integer and returns it.
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Per protocol v3, the encoded value must be encoded with
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the minimum amount of data possible or else it is malformed.
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Returns a tuple: (theEncodedValue, theSizeOfTheVarintInBytes)
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"""
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if not data:
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return (0, 0)
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firstByte, = unpack('>B', data[0:1])
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if firstByte < 253:
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# encodes 0 to 252
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return (firstByte, 1) # the 1 is the length of the varint
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if firstByte == 253:
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# encodes 253 to 65535
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if len(data) < 3:
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raise varintDecodeError(
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'The first byte of this varint as an integer is %s'
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' but the total length is only %s. It needs to be'
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' at least 3.' % (firstByte, len(data)))
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encodedValue, = unpack('>H', data[1:3])
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if encodedValue < 253:
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raise varintDecodeError(
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'This varint does not encode the value with the lowest'
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' possible number of bytes.')
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return (encodedValue, 3)
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if firstByte == 254:
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# encodes 65536 to 4294967295
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if len(data) < 5:
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raise varintDecodeError(
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'The first byte of this varint as an integer is %s'
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' but the total length is only %s. It needs to be'
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' at least 5.' % (firstByte, len(data)))
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encodedValue, = unpack('>I', data[1:5])
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if encodedValue < 65536:
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raise varintDecodeError(
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'This varint does not encode the value with the lowest'
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' possible number of bytes.')
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return (encodedValue, 5)
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if firstByte == 255:
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# encodes 4294967296 to 18446744073709551615
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if len(data) < 9:
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raise varintDecodeError(
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'The first byte of this varint as an integer is %s'
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' but the total length is only %s. It needs to be'
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' at least 9.' % (firstByte, len(data)))
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encodedValue, = unpack('>Q', data[1:9])
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if encodedValue < 4294967296:
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raise varintDecodeError(
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'This varint does not encode the value with the lowest'
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' possible number of bytes.')
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return (encodedValue, 9)
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def calculateInventoryHash(data):
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"""Calculate inventory hash from object data"""
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sha = hashlib.new('sha512')
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sha2 = hashlib.new('sha512')
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sha.update(data)
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sha2.update(sha.digest())
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return sha2.digest()[0:32]
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def encodeAddress(version, stream, ripe):
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"""Convert ripe to address"""
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if version >= 2 and version < 4:
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if len(ripe) != 20:
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raise Exception(
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'Programming error in encodeAddress: The length of'
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' a given ripe hash was not 20.'
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)
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if ripe[:2] == b'\x00\x00':
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ripe = ripe[2:]
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elif ripe[:1] == b'\x00':
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ripe = ripe[1:]
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elif version == 4:
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if len(ripe) != 20:
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raise Exception(
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'Programming error in encodeAddress: The length of'
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' a given ripe hash was not 20.')
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ripe = ripe.lstrip(b'\x00')
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storedBinaryData = encodeVarint(version) + encodeVarint(stream) + ripe
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# Generate the checksum
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sha = hashlib.new('sha512')
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sha.update(storedBinaryData)
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currentHash = sha.digest()
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sha = hashlib.new('sha512')
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sha.update(currentHash)
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checksum = sha.digest()[0:4]
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# FIXME: encodeBase58 should take binary data, to reduce conversions
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# encodeBase58(storedBinaryData + checksum)
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asInt = int(hexlify(storedBinaryData) + hexlify(checksum), 16)
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# should it be str? If yes, it should be everywhere in the code
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return 'BM-' + encodeBase58(asInt)
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def decodeAddress(address):
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"""
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returns (status, address version number, stream number,
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data (almost certainly a ripe hash))
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"""
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# pylint: disable=too-many-return-statements,too-many-statements
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# pylint: disable=too-many-branches
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address = str(address).strip()
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if address[:3] == 'BM-':
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integer = decodeBase58(address[3:])
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else:
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integer = decodeBase58(address)
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if integer == 0:
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status = 'invalidcharacters'
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return status, 0, 0, ''
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# after converting to hex, the string will be prepended
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# with a 0x and appended with a L in python2
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hexdata = hex(integer)[2:].rstrip('L')
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if len(hexdata) % 2 != 0:
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hexdata = '0' + hexdata
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data = unhexlify(hexdata)
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checksum = data[-4:]
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sha = hashlib.new('sha512')
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sha.update(data[:-4])
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currentHash = sha.digest()
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sha = hashlib.new('sha512')
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sha.update(currentHash)
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if checksum != sha.digest()[0:4]:
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status = 'checksumfailed'
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return status, 0, 0, ''
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try:
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addressVersionNumber, bytesUsedByVersionNumber = decodeVarint(data[:9])
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except varintDecodeError as e:
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logger.error(str(e))
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status = 'varintmalformed'
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return status, 0, 0, ''
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if addressVersionNumber > 4:
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logger.error('cannot decode address version numbers this high')
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status = 'versiontoohigh'
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return status, 0, 0, ''
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elif addressVersionNumber == 0:
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logger.error('cannot decode address version numbers of zero.')
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status = 'versiontoohigh'
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return status, 0, 0, ''
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try:
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streamNumber, bytesUsedByStreamNumber = \
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decodeVarint(data[bytesUsedByVersionNumber:])
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except varintDecodeError as e:
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logger.error(str(e))
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status = 'varintmalformed'
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return status, 0, 0, ''
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status = 'success'
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if addressVersionNumber == 1:
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return status, addressVersionNumber, streamNumber, data[-24:-4]
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elif addressVersionNumber == 2 or addressVersionNumber == 3:
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embeddedRipeData = \
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data[bytesUsedByVersionNumber + bytesUsedByStreamNumber:-4]
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if len(embeddedRipeData) == 19:
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return status, addressVersionNumber, streamNumber, \
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b'\x00' + embeddedRipeData
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elif len(embeddedRipeData) == 20:
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return status, addressVersionNumber, streamNumber, \
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embeddedRipeData
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elif len(embeddedRipeData) == 18:
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return status, addressVersionNumber, streamNumber, \
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b'\x00\x00' + embeddedRipeData
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elif len(embeddedRipeData) < 18:
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return 'ripetooshort', 0, 0, ''
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elif len(embeddedRipeData) > 20:
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return 'ripetoolong', 0, 0, ''
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return 'otherproblem', 0, 0, ''
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elif addressVersionNumber == 4:
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embeddedRipeData = \
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data[bytesUsedByVersionNumber + bytesUsedByStreamNumber:-4]
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if embeddedRipeData[0:1] == b'\x00':
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# In order to enforce address non-malleability, encoded
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# RIPE data must have NULL bytes removed from the front
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return 'encodingproblem', 0, 0, ''
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elif len(embeddedRipeData) > 20:
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return 'ripetoolong', 0, 0, ''
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elif len(embeddedRipeData) < 4:
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return 'ripetooshort', 0, 0, ''
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x00string = b'\x00' * (20 - len(embeddedRipeData))
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return status, addressVersionNumber, streamNumber, \
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x00string + embeddedRipeData
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def addBMIfNotPresent(address):
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"""Prepend BM- to an address if it doesn't already have it"""
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address = str(address).strip()
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return address if address[:3] == 'BM-' else 'BM-' + address
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