linux/crypto/crct10dif_generic.c
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   1/*
   2 * Cryptographic API.
   3 *
   4 * T10 Data Integrity Field CRC16 Crypto Transform
   5 *
   6 * Copyright (c) 2007 Oracle Corporation.  All rights reserved.
   7 * Written by Martin K. Petersen <martin.petersen@oracle.com>
   8 * Copyright (C) 2013 Intel Corporation
   9 * Author: Tim Chen <tim.c.chen@linux.intel.com>
  10 *
  11 * This program is free software; you can redistribute it and/or modify it
  12 * under the terms of the GNU General Public License as published by the Free
  13 * Software Foundation; either version 2 of the License, or (at your option)
  14 * any later version.
  15 *
  16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  17 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  19 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  20 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  21 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23 * SOFTWARE.
  24 *
  25 */
  26
  27#include <linux/module.h>
  28#include <linux/crc-t10dif.h>
  29#include <crypto/internal/hash.h>
  30#include <linux/init.h>
  31#include <linux/kernel.h>
  32
  33struct chksum_desc_ctx {
  34        __u16 crc;
  35};
  36
  37/*
  38 * Steps through buffer one byte at at time, calculates reflected
  39 * crc using table.
  40 */
  41
  42static int chksum_init(struct shash_desc *desc)
  43{
  44        struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
  45
  46        ctx->crc = 0;
  47
  48        return 0;
  49}
  50
  51static int chksum_update(struct shash_desc *desc, const u8 *data,
  52                         unsigned int length)
  53{
  54        struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
  55
  56        ctx->crc = crc_t10dif_generic(ctx->crc, data, length);
  57        return 0;
  58}
  59
  60static int chksum_final(struct shash_desc *desc, u8 *out)
  61{
  62        struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
  63
  64        *(__u16 *)out = ctx->crc;
  65        return 0;
  66}
  67
  68static int __chksum_finup(__u16 *crcp, const u8 *data, unsigned int len,
  69                        u8 *out)
  70{
  71        *(__u16 *)out = crc_t10dif_generic(*crcp, data, len);
  72        return 0;
  73}
  74
  75static int chksum_finup(struct shash_desc *desc, const u8 *data,
  76                        unsigned int len, u8 *out)
  77{
  78        struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
  79
  80        return __chksum_finup(&ctx->crc, data, len, out);
  81}
  82
  83static int chksum_digest(struct shash_desc *desc, const u8 *data,
  84                         unsigned int length, u8 *out)
  85{
  86        struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
  87
  88        return __chksum_finup(&ctx->crc, data, length, out);
  89}
  90
  91static struct shash_alg alg = {
  92        .digestsize             =       CRC_T10DIF_DIGEST_SIZE,
  93        .init           =       chksum_init,
  94        .update         =       chksum_update,
  95        .final          =       chksum_final,
  96        .finup          =       chksum_finup,
  97        .digest         =       chksum_digest,
  98        .descsize               =       sizeof(struct chksum_desc_ctx),
  99        .base                   =       {
 100                .cra_name               =       "crct10dif",
 101                .cra_driver_name        =       "crct10dif-generic",
 102                .cra_priority           =       100,
 103                .cra_blocksize          =       CRC_T10DIF_BLOCK_SIZE,
 104                .cra_module             =       THIS_MODULE,
 105        }
 106};
 107
 108static int __init crct10dif_mod_init(void)
 109{
 110        int ret;
 111
 112        ret = crypto_register_shash(&alg);
 113        return ret;
 114}
 115
 116static void __exit crct10dif_mod_fini(void)
 117{
 118        crypto_unregister_shash(&alg);
 119}
 120
 121module_init(crct10dif_mod_init);
 122module_exit(crct10dif_mod_fini);
 123
 124MODULE_AUTHOR("Tim Chen <tim.c.chen@linux.intel.com>");
 125MODULE_DESCRIPTION("T10 DIF CRC calculation.");
 126MODULE_LICENSE("GPL");
 127MODULE_ALIAS("crct10dif");
 128
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