Package dpkt :: Module crc32c
[hide private]
[frames] | no frames]

Source Code for Module dpkt.crc32c

  1  # $Id: crc32c.py 23 2006-11-08 15:45:33Z dugsong $ 
  2  # -*- coding: utf-8 -*- 
  3  from __future__ import absolute_import 
  4   
  5  import array 
  6   
  7  # CRC-32C Checksum for SCTP 
  8  # http://tools.ietf.org/html/rfc3309 
  9   
 10  crc32c_table = ( 
 11      0x00000000, 0xF26B8303, 0xE13B70F7, 0x1350F3F4, 0xC79A971F, 
 12      0x35F1141C, 0x26A1E7E8, 0xD4CA64EB, 0x8AD958CF, 0x78B2DBCC, 
 13      0x6BE22838, 0x9989AB3B, 0x4D43CFD0, 0xBF284CD3, 0xAC78BF27, 
 14      0x5E133C24, 0x105EC76F, 0xE235446C, 0xF165B798, 0x030E349B, 
 15      0xD7C45070, 0x25AFD373, 0x36FF2087, 0xC494A384, 0x9A879FA0, 
 16      0x68EC1CA3, 0x7BBCEF57, 0x89D76C54, 0x5D1D08BF, 0xAF768BBC, 
 17      0xBC267848, 0x4E4DFB4B, 0x20BD8EDE, 0xD2D60DDD, 0xC186FE29, 
 18      0x33ED7D2A, 0xE72719C1, 0x154C9AC2, 0x061C6936, 0xF477EA35, 
 19      0xAA64D611, 0x580F5512, 0x4B5FA6E6, 0xB93425E5, 0x6DFE410E, 
 20      0x9F95C20D, 0x8CC531F9, 0x7EAEB2FA, 0x30E349B1, 0xC288CAB2, 
 21      0xD1D83946, 0x23B3BA45, 0xF779DEAE, 0x05125DAD, 0x1642AE59, 
 22      0xE4292D5A, 0xBA3A117E, 0x4851927D, 0x5B016189, 0xA96AE28A, 
 23      0x7DA08661, 0x8FCB0562, 0x9C9BF696, 0x6EF07595, 0x417B1DBC, 
 24      0xB3109EBF, 0xA0406D4B, 0x522BEE48, 0x86E18AA3, 0x748A09A0, 
 25      0x67DAFA54, 0x95B17957, 0xCBA24573, 0x39C9C670, 0x2A993584, 
 26      0xD8F2B687, 0x0C38D26C, 0xFE53516F, 0xED03A29B, 0x1F682198, 
 27      0x5125DAD3, 0xA34E59D0, 0xB01EAA24, 0x42752927, 0x96BF4DCC, 
 28      0x64D4CECF, 0x77843D3B, 0x85EFBE38, 0xDBFC821C, 0x2997011F, 
 29      0x3AC7F2EB, 0xC8AC71E8, 0x1C661503, 0xEE0D9600, 0xFD5D65F4, 
 30      0x0F36E6F7, 0x61C69362, 0x93AD1061, 0x80FDE395, 0x72966096, 
 31      0xA65C047D, 0x5437877E, 0x4767748A, 0xB50CF789, 0xEB1FCBAD, 
 32      0x197448AE, 0x0A24BB5A, 0xF84F3859, 0x2C855CB2, 0xDEEEDFB1, 
 33      0xCDBE2C45, 0x3FD5AF46, 0x7198540D, 0x83F3D70E, 0x90A324FA, 
 34      0x62C8A7F9, 0xB602C312, 0x44694011, 0x5739B3E5, 0xA55230E6, 
 35      0xFB410CC2, 0x092A8FC1, 0x1A7A7C35, 0xE811FF36, 0x3CDB9BDD, 
 36      0xCEB018DE, 0xDDE0EB2A, 0x2F8B6829, 0x82F63B78, 0x709DB87B, 
 37      0x63CD4B8F, 0x91A6C88C, 0x456CAC67, 0xB7072F64, 0xA457DC90, 
 38      0x563C5F93, 0x082F63B7, 0xFA44E0B4, 0xE9141340, 0x1B7F9043, 
 39      0xCFB5F4A8, 0x3DDE77AB, 0x2E8E845F, 0xDCE5075C, 0x92A8FC17, 
 40      0x60C37F14, 0x73938CE0, 0x81F80FE3, 0x55326B08, 0xA759E80B, 
 41      0xB4091BFF, 0x466298FC, 0x1871A4D8, 0xEA1A27DB, 0xF94AD42F, 
 42      0x0B21572C, 0xDFEB33C7, 0x2D80B0C4, 0x3ED04330, 0xCCBBC033, 
 43      0xA24BB5A6, 0x502036A5, 0x4370C551, 0xB11B4652, 0x65D122B9, 
 44      0x97BAA1BA, 0x84EA524E, 0x7681D14D, 0x2892ED69, 0xDAF96E6A, 
 45      0xC9A99D9E, 0x3BC21E9D, 0xEF087A76, 0x1D63F975, 0x0E330A81, 
 46      0xFC588982, 0xB21572C9, 0x407EF1CA, 0x532E023E, 0xA145813D, 
 47      0x758FE5D6, 0x87E466D5, 0x94B49521, 0x66DF1622, 0x38CC2A06, 
 48      0xCAA7A905, 0xD9F75AF1, 0x2B9CD9F2, 0xFF56BD19, 0x0D3D3E1A, 
 49      0x1E6DCDEE, 0xEC064EED, 0xC38D26C4, 0x31E6A5C7, 0x22B65633, 
 50      0xD0DDD530, 0x0417B1DB, 0xF67C32D8, 0xE52CC12C, 0x1747422F, 
 51      0x49547E0B, 0xBB3FFD08, 0xA86F0EFC, 0x5A048DFF, 0x8ECEE914, 
 52      0x7CA56A17, 0x6FF599E3, 0x9D9E1AE0, 0xD3D3E1AB, 0x21B862A8, 
 53      0x32E8915C, 0xC083125F, 0x144976B4, 0xE622F5B7, 0xF5720643, 
 54      0x07198540, 0x590AB964, 0xAB613A67, 0xB831C993, 0x4A5A4A90, 
 55      0x9E902E7B, 0x6CFBAD78, 0x7FAB5E8C, 0x8DC0DD8F, 0xE330A81A, 
 56      0x115B2B19, 0x020BD8ED, 0xF0605BEE, 0x24AA3F05, 0xD6C1BC06, 
 57      0xC5914FF2, 0x37FACCF1, 0x69E9F0D5, 0x9B8273D6, 0x88D28022, 
 58      0x7AB90321, 0xAE7367CA, 0x5C18E4C9, 0x4F48173D, 0xBD23943E, 
 59      0xF36E6F75, 0x0105EC76, 0x12551F82, 0xE03E9C81, 0x34F4F86A, 
 60      0xC69F7B69, 0xD5CF889D, 0x27A40B9E, 0x79B737BA, 0x8BDCB4B9, 
 61      0x988C474D, 0x6AE7C44E, 0xBE2DA0A5, 0x4C4623A6, 0x5F16D052, 
 62      0xAD7D5351 
 63  ) 
 64   
 65   
66 -def add(crc, buf):
67 byte_buf = array.array('B', buf) 68 for b in byte_buf: 69 crc = (crc >> 8) ^ crc32c_table[(crc ^ b) & 0xff] 70 return crc
71 72
73 -def done(crc):
74 tmp = ~crc & 0xffffffff 75 b0 = tmp & 0xff 76 b1 = (tmp >> 8) & 0xff 77 b2 = (tmp >> 16) & 0xff 78 b3 = (tmp >> 24) & 0xff 79 crc = (b0 << 24) | (b1 << 16) | (b2 << 8) | b3 80 return crc
81 82
83 -def cksum(buf):
84 """Return computed CRC-32c checksum.""" 85 return done(add(0xffffffff, buf))
86 87
88 -def test_crc32c():
89 90 def bswap32(x): 91 from struct import pack, unpack 92 return unpack('<I', pack('>I', x))[0]
93 94 # reference test value from CRC catalogue 95 # http://reveng.sourceforge.net/crc-catalogue/17plus.htm#crc.cat.crc-32c 96 # SCTP uses tranport-level mirrored byte ordering, so we bswap32 97 98 assert cksum(b'') == 0 99 assert cksum(b'123456789') == bswap32(0xe3069283) 100 101 102 if __name__ == '__main__': 103 test_crc32c() 104 print('Tests Successful...') 105