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crypto/crc32c.c
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/* |
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* Cryptographic API. * * CRC32C chksum * |
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*@Article{castagnoli-crc, * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman}, * title = {{Optimization of Cyclic Redundancy-Check Codes with 24 * and 32 Parity Bits}}, * journal = IEEE Transactions on Communication, * year = {1993}, * volume = {41}, * number = {6}, * pages = {}, * month = {June}, *} * Used by the iSCSI driver, possibly others, and derived from the * the iscsi-crc.c module of the linux-iscsi driver at * http://linux-iscsi.sourceforge.net. |
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* |
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* Following the example of lib/crc32, this function is intended to be * flexible and useful for all users. Modules that currently have their * own crc32c, but hopefully may be able to use this one are: * net/sctp (please add all your doco to here if you change to * use this one!) * <endoflist> * * Copyright (c) 2004 Cisco Systems, Inc. |
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* Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au> * |
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* This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free |
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* Software Foundation; either version 2 of the License, or (at your option) |
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* any later version. * */ |
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#include <crypto/internal/hash.h> |
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#include <linux/init.h> #include <linux/module.h> #include <linux/string.h> |
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#include <linux/kernel.h> |
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#define CHKSUM_BLOCK_SIZE 1 |
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#define CHKSUM_DIGEST_SIZE 4 struct chksum_ctx { |
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u32 key; |
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}; |
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struct chksum_desc_ctx { u32 crc; }; |
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/* |
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* This is the CRC-32C table * Generated with: * width = 32 bits * poly = 0x1EDC6F41 * reflect input bytes = true * reflect output bytes = true */ static const u32 crc32c_table[256] = { 0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L, 0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL, 0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL, 0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L, 0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL, 0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L, 0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L, 0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL, 0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL, 0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L, 0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L, 0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL, 0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L, 0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL, 0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL, 0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L, 0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L, 0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L, 0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L, 0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L, 0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L, 0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L, 0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L, 0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L, 0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L, 0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L, 0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L, 0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L, 0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L, 0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L, 0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L, 0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L, 0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL, 0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L, 0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L, 0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL, 0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L, 0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL, 0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL, 0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L, 0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L, 0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL, 0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL, 0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L, 0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL, 0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L, 0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L, 0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL, 0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L, 0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL, 0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL, 0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L, 0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL, 0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L, 0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L, 0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL, 0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL, 0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L, 0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L, 0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL, 0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L, 0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL, 0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL, 0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L }; /* * Steps through buffer one byte at at time, calculates reflected * crc using table. */ static u32 crc32c(u32 crc, const u8 *data, unsigned int length) { while (length--) crc = crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8); return crc; } /* |
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* Steps through buffer one byte at at time, calculates reflected |
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* crc using table. */ |
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static int chksum_init(struct shash_desc *desc) |
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{ |
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struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm); struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); ctx->crc = mctx->key; |
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return 0; |
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} /* * Setting the seed allows arbitrary accumulators and flexible XOR policy * If your algorithm starts with ~0, then XOR with ~0 before you set * the seed. */ |
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static int chksum_setkey(struct crypto_shash *tfm, const u8 *key, |
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unsigned int keylen) |
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{ |
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struct chksum_ctx *mctx = crypto_shash_ctx(tfm); |
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if (keylen != sizeof(mctx->key)) { crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); |
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return -EINVAL; } |
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mctx->key = le32_to_cpu(*(__le32 *)key); |
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return 0; } |
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static int chksum_update(struct shash_desc *desc, const u8 *data, unsigned int length) |
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{ |
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struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
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ctx->crc = crc32c(ctx->crc, data, length); |
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return 0; |
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} |
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static int chksum_final(struct shash_desc *desc, u8 *out) |
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{ |
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struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
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*(__le32 *)out = ~cpu_to_le32p(&ctx->crc); |
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return 0; } |
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static int __chksum_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out) |
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{ |
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*(__le32 *)out = ~cpu_to_le32(crc32c(*crcp, data, len)); |
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return 0; } |
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static int chksum_finup(struct shash_desc *desc, const u8 *data, unsigned int len, u8 *out) |
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{ |
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struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
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return __chksum_finup(&ctx->crc, data, len, out); |
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} |
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static int chksum_digest(struct shash_desc *desc, const u8 *data, unsigned int length, u8 *out) |
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{ |
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struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm); |
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return __chksum_finup(&mctx->key, data, length, out); |
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} static int crc32c_cra_init(struct crypto_tfm *tfm) { |
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struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); |
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mctx->key = ~0; |
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return 0; } |
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static struct shash_alg alg = { .digestsize = CHKSUM_DIGEST_SIZE, .setkey = chksum_setkey, |
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.init = chksum_init, .update = chksum_update, .final = chksum_final, .finup = chksum_finup, .digest = chksum_digest, |
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.descsize = sizeof(struct chksum_desc_ctx), .base = { .cra_name = "crc32c", .cra_driver_name = "crc32c-generic", .cra_priority = 100, .cra_blocksize = CHKSUM_BLOCK_SIZE, .cra_alignmask = 3, .cra_ctxsize = sizeof(struct chksum_ctx), .cra_module = THIS_MODULE, .cra_init = crc32c_cra_init, |
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} }; |
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static int __init crc32c_mod_init(void) |
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{ |
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return crypto_register_shash(&alg); |
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} |
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static void __exit crc32c_mod_fini(void) |
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{ |
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crypto_unregister_shash(&alg); |
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} |
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module_init(crc32c_mod_init); module_exit(crc32c_mod_fini); |
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MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>"); MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c"); MODULE_LICENSE("GPL"); |