libcrc32c.c 6.5 KB

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  1. /*
  2. * CRC32C
  3. *@Article{castagnoli-crc,
  4. * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
  5. * title = {{Optimization of Cyclic Redundancy-Check Codes with 24
  6. * and 32 Parity Bits}},
  7. * journal = IEEE Transactions on Communication,
  8. * year = {1993},
  9. * volume = {41},
  10. * number = {6},
  11. * pages = {},
  12. * month = {June},
  13. *}
  14. * Used by the iSCSI driver, possibly others, and derived from the
  15. * the iscsi-crc.c module of the linux-iscsi driver at
  16. * http://linux-iscsi.sourceforge.net.
  17. *
  18. * Following the example of lib/crc32, this function is intended to be
  19. * flexible and useful for all users. Modules that currently have their
  20. * own crc32c, but hopefully may be able to use this one are:
  21. * net/sctp (please add all your doco to here if you change to
  22. * use this one!)
  23. * <endoflist>
  24. *
  25. * Copyright (c) 2004 Cisco Systems, Inc.
  26. *
  27. * This program is free software; you can redistribute it and/or modify it
  28. * under the terms of the GNU General Public License as published by the Free
  29. * Software Foundation; either version 2 of the License, or (at your option)
  30. * any later version.
  31. *
  32. */
  33. #include <linux/crc32c.h>
  34. #include <linux/compiler.h>
  35. #include <linux/module.h>
  36. #include <asm/byteorder.h>
  37. MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
  38. MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
  39. MODULE_LICENSE("GPL");
  40. #define CRC32C_POLY_BE 0x1EDC6F41
  41. #define CRC32C_POLY_LE 0x82F63B78
  42. #ifndef CRC_LE_BITS
  43. # define CRC_LE_BITS 8
  44. #endif
  45. /*
  46. * Haven't generated a big-endian table yet, but the bit-wise version
  47. * should at least work.
  48. */
  49. #if defined CRC_BE_BITS && CRC_BE_BITS != 1
  50. #undef CRC_BE_BITS
  51. #endif
  52. #ifndef CRC_BE_BITS
  53. # define CRC_BE_BITS 1
  54. #endif
  55. EXPORT_SYMBOL(crc32c_le);
  56. #if CRC_LE_BITS == 1
  57. /*
  58. * Compute things bit-wise, as done in crc32.c. We could share the tight
  59. * loop below with crc32 and vary the POLY if we don't find value in terms
  60. * of space and maintainability in keeping the two modules separate.
  61. */
  62. u32 __attribute_pure__
  63. crc32c_le(u32 crc, unsigned char const *p, size_t len)
  64. {
  65. int i;
  66. while (len--) {
  67. crc ^= *p++;
  68. for (i = 0; i < 8; i++)
  69. crc = (crc >> 1) ^ ((crc & 1) ? CRC32C_POLY_LE : 0);
  70. }
  71. return crc;
  72. }
  73. #else
  74. /*
  75. * This is the CRC-32C table
  76. * Generated with:
  77. * width = 32 bits
  78. * poly = 0x1EDC6F41
  79. * reflect input bytes = true
  80. * reflect output bytes = true
  81. */
  82. static const u32 crc32c_table[256] = {
  83. 0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L,
  84. 0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL,
  85. 0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL,
  86. 0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L,
  87. 0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL,
  88. 0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L,
  89. 0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L,
  90. 0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL,
  91. 0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL,
  92. 0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L,
  93. 0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L,
  94. 0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL,
  95. 0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L,
  96. 0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL,
  97. 0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL,
  98. 0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L,
  99. 0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L,
  100. 0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L,
  101. 0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L,
  102. 0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L,
  103. 0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L,
  104. 0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L,
  105. 0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L,
  106. 0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L,
  107. 0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L,
  108. 0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L,
  109. 0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L,
  110. 0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L,
  111. 0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L,
  112. 0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L,
  113. 0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L,
  114. 0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L,
  115. 0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL,
  116. 0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L,
  117. 0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L,
  118. 0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL,
  119. 0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L,
  120. 0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL,
  121. 0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL,
  122. 0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L,
  123. 0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L,
  124. 0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL,
  125. 0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL,
  126. 0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L,
  127. 0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL,
  128. 0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L,
  129. 0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L,
  130. 0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL,
  131. 0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L,
  132. 0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL,
  133. 0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL,
  134. 0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L,
  135. 0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL,
  136. 0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L,
  137. 0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L,
  138. 0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL,
  139. 0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL,
  140. 0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L,
  141. 0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L,
  142. 0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL,
  143. 0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L,
  144. 0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL,
  145. 0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL,
  146. 0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L
  147. };
  148. /*
  149. * Steps through buffer one byte at at time, calculates reflected
  150. * crc using table.
  151. */
  152. u32 __attribute_pure__
  153. crc32c_le(u32 seed, unsigned char const *data, size_t length)
  154. {
  155. u32 crc = __cpu_to_le32(seed);
  156. while (length--)
  157. crc =
  158. crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8);
  159. return __le32_to_cpu(crc);
  160. }
  161. #endif /* CRC_LE_BITS == 8 */
  162. EXPORT_SYMBOL(crc32c_be);
  163. #if CRC_BE_BITS == 1
  164. u32 __attribute_pure__
  165. crc32c_be(u32 crc, unsigned char const *p, size_t len)
  166. {
  167. int i;
  168. while (len--) {
  169. crc ^= *p++ << 24;
  170. for (i = 0; i < 8; i++)
  171. crc =
  172. (crc << 1) ^ ((crc & 0x80000000) ? CRC32C_POLY_BE :
  173. 0);
  174. }
  175. return crc;
  176. }
  177. #endif
  178. /*
  179. * Unit test
  180. *
  181. * A small unit test suite is implemented as part of the crypto suite.
  182. * Select CRYPTO_CRC32C and use the tcrypt module to run the tests.
  183. */