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 37 MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>"); 38 MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations"); 39 MODULE_LICENSE("GPL"); 40 41 #define CRC32C_POLY_BE 0x1EDC6F41 42 #define CRC32C_POLY_LE 0x82F63B78 43 44 #ifndef CRC_LE_BITS 45 # define CRC_LE_BITS 8 46 #endif 47 48 49 /* 50 * Haven't generated a big-endian table yet, but the bit-wise version 51 * should at least work. 52 */ 53 #if defined CRC_BE_BITS && CRC_BE_BITS != 1 54 #undef CRC_BE_BITS 55 #endif 56 #ifndef CRC_BE_BITS 57 # define CRC_BE_BITS 1 58 #endif 59 60 EXPORT_SYMBOL(crc32c_le); 61 62 #if CRC_LE_BITS == 1 63 /* 64 * Compute things bit-wise, as done in crc32.c. We could share the tight 65 * loop below with crc32 and vary the POLY if we don't find value in terms 66 * of space and maintainability in keeping the two modules separate. 67 */ 68 u32 __pure 69 crc32c_le(u32 crc, unsigned char const *p, size_t len) 70 { 71 int i; 72 while (len--) { 73 crc ^= *p++; 74 for (i = 0; i < 8; i++) 75 crc = (crc >> 1) ^ ((crc & 1) ? CRC32C_POLY_LE : 0); 76 } 77 return crc; 78 } 79 #else 80 81 /* 82 * This is the CRC-32C table 83 * Generated with: 84 * width = 32 bits 85 * poly = 0x1EDC6F41 86 * reflect input bytes = true 87 * reflect output bytes = true 88 */ 89 90 static const u32 crc32c_table[256] = { 91 0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L, 92 0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL, 93 0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL, 94 0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L, 95 0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL, 96 0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L, 97 0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L, 98 0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL, 99 0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL, 100 0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L, 101 0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L, 102 0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL, 103 0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L, 104 0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL, 105 0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL, 106 0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L, 107 0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L, 108 0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L, 109 0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L, 110 0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L, 111 0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L, 112 0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L, 113 0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L, 114 0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L, 115 0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L, 116 0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L, 117 0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L, 118 0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L, 119 0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L, 120 0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L, 121 0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L, 122 0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L, 123 0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL, 124 0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L, 125 0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L, 126 0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL, 127 0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L, 128 0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL, 129 0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL, 130 0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L, 131 0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L, 132 0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL, 133 0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL, 134 0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L, 135 0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL, 136 0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L, 137 0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L, 138 0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL, 139 0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L, 140 0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL, 141 0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL, 142 0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L, 143 0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL, 144 0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L, 145 0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L, 146 0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL, 147 0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL, 148 0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L, 149 0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L, 150 0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL, 151 0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L, 152 0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL, 153 0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL, 154 0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L 155 }; 156 157 /* 158 * Steps through buffer one byte at at time, calculates reflected 159 * crc using table. 160 */ 161 162 u32 __pure 163 crc32c_le(u32 crc, unsigned char const *data, size_t length) 164 { 165 while (length--) 166 crc = 167 crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8); 168 169 return crc; 170 } 171 172 #endif /* CRC_LE_BITS == 8 */ 173 174 EXPORT_SYMBOL(crc32c_be); 175 176 #if CRC_BE_BITS == 1 177 u32 __pure 178 crc32c_be(u32 crc, unsigned char const *p, size_t len) 179 { 180 int i; 181 while (len--) { 182 crc ^= *p++ << 24; 183 for (i = 0; i < 8; i++) 184 crc = 185 (crc << 1) ^ ((crc & 0x80000000) ? CRC32C_POLY_BE : 186 0); 187 } 188 return crc; 189 } 190 #endif 191 192 /* 193 * Unit test 194 * 195 * A small unit test suite is implemented as part of the crypto suite. 196 * Select CRYPTO_CRC32C and use the tcrypt module to run the tests. 197 */ 198