|  | /* | 
|  | * Cryptographic API. | 
|  | * | 
|  | * CRC32C chksum | 
|  | * | 
|  | *@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. | 
|  | * | 
|  | * 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. | 
|  | * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au> | 
|  | * | 
|  | * 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 | 
|  | * Software Foundation; either version 2 of the License, or (at your option) | 
|  | * any later version. | 
|  | * | 
|  | */ | 
|  |  | 
|  | #include <crypto/internal/hash.h> | 
|  | #include <linux/init.h> | 
|  | #include <linux/module.h> | 
|  | #include <linux/string.h> | 
|  | #include <linux/kernel.h> | 
|  |  | 
|  | #define CHKSUM_BLOCK_SIZE	1 | 
|  | #define CHKSUM_DIGEST_SIZE	4 | 
|  |  | 
|  | struct chksum_ctx { | 
|  | u32 key; | 
|  | }; | 
|  |  | 
|  | struct chksum_desc_ctx { | 
|  | u32 crc; | 
|  | }; | 
|  |  | 
|  | /* | 
|  | * 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; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Steps through buffer one byte at at time, calculates reflected | 
|  | * crc using table. | 
|  | */ | 
|  |  | 
|  | static int chksum_init(struct shash_desc *desc) | 
|  | { | 
|  | struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm); | 
|  | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); | 
|  |  | 
|  | ctx->crc = mctx->key; | 
|  |  | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * 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. | 
|  | */ | 
|  | static int chksum_setkey(struct crypto_shash *tfm, const u8 *key, | 
|  | unsigned int keylen) | 
|  | { | 
|  | struct chksum_ctx *mctx = crypto_shash_ctx(tfm); | 
|  |  | 
|  | if (keylen != sizeof(mctx->key)) { | 
|  | crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); | 
|  | return -EINVAL; | 
|  | } | 
|  | mctx->key = le32_to_cpu(*(__le32 *)key); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static int chksum_update(struct shash_desc *desc, const u8 *data, | 
|  | unsigned int length) | 
|  | { | 
|  | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); | 
|  |  | 
|  | ctx->crc = crc32c(ctx->crc, data, length); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static int chksum_final(struct shash_desc *desc, u8 *out) | 
|  | { | 
|  | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); | 
|  |  | 
|  | *(__le32 *)out = ~cpu_to_le32p(&ctx->crc); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static int __chksum_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out) | 
|  | { | 
|  | *(__le32 *)out = ~cpu_to_le32(crc32c(*crcp, data, len)); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static int chksum_finup(struct shash_desc *desc, const u8 *data, | 
|  | unsigned int len, u8 *out) | 
|  | { | 
|  | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); | 
|  |  | 
|  | return __chksum_finup(&ctx->crc, data, len, out); | 
|  | } | 
|  |  | 
|  | static int chksum_digest(struct shash_desc *desc, const u8 *data, | 
|  | unsigned int length, u8 *out) | 
|  | { | 
|  | struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm); | 
|  |  | 
|  | return __chksum_finup(&mctx->key, data, length, out); | 
|  | } | 
|  |  | 
|  | static int crc32c_cra_init(struct crypto_tfm *tfm) | 
|  | { | 
|  | struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); | 
|  |  | 
|  | mctx->key = ~0; | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static struct shash_alg alg = { | 
|  | .digestsize		=	CHKSUM_DIGEST_SIZE, | 
|  | .setkey			=	chksum_setkey, | 
|  | .init		=	chksum_init, | 
|  | .update		=	chksum_update, | 
|  | .final		=	chksum_final, | 
|  | .finup		=	chksum_finup, | 
|  | .digest		=	chksum_digest, | 
|  | .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, | 
|  | } | 
|  | }; | 
|  |  | 
|  | static int __init crc32c_mod_init(void) | 
|  | { | 
|  | return crypto_register_shash(&alg); | 
|  | } | 
|  |  | 
|  | static void __exit crc32c_mod_fini(void) | 
|  | { | 
|  | crypto_unregister_shash(&alg); | 
|  | } | 
|  |  | 
|  | module_init(crc32c_mod_init); | 
|  | module_exit(crc32c_mod_fini); | 
|  |  | 
|  | MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>"); | 
|  | MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c"); | 
|  | MODULE_LICENSE("GPL"); |