crypto/crct10dif_generic.c

   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
  33 struct 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
  42 static 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
  51 static 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
  60 static 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
  68 static int __chksum_finup(__u16 crc, const u8 *data, unsigned int len, u8 *out)
  69 {
  70         *(__u16 *)out = crc_t10dif_generic(crc, data, len);
  71         return 0;
  72 }
  73
  74 static int chksum_finup(struct shash_desc *desc, const u8 *data,
  75                         unsigned int len, u8 *out)
  76 {
  77         struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
  78
  79         return __chksum_finup(ctx->crc, data, len, out);
  80 }
  81
  82 static int chksum_digest(struct shash_desc *desc, const u8 *data,
  83                          unsigned int length, u8 *out)
  84 {
  85         return __chksum_finup(0, data, length, out);
  86 }
  87
  88 static struct shash_alg alg = {
  89         .digestsize             =       CRC_T10DIF_DIGEST_SIZE,
  90         .init           =       chksum_init,
  91         .update         =       chksum_update,
  92         .final          =       chksum_final,
  93         .finup          =       chksum_finup,
  94         .digest         =       chksum_digest,
  95         .descsize               =       sizeof(struct chksum_desc_ctx),
  96         .base                   =       {
  97                 .cra_name               =       "crct10dif",
  98                 .cra_driver_name        =       "crct10dif-generic",
  99                 .cra_priority           =       100,
 100                 .cra_blocksize          =       CRC_T10DIF_BLOCK_SIZE,
 101                 .cra_module             =       THIS_MODULE,
 102         }
 103 };
 104
 105 static int __init crct10dif_mod_init(void)
 106 {
 107         return crypto_register_shash(&alg);
 108 }
 109
 110 static void __exit crct10dif_mod_fini(void)
 111 {
 112         crypto_unregister_shash(&alg);
 113 }
 114
 115 subsys_initcall(crct10dif_mod_init);
 116 module_exit(crct10dif_mod_fini);
 117
 118 MODULE_AUTHOR("Tim Chen <tim.c.chen@linux.intel.com>");
 119 MODULE_DESCRIPTION("T10 DIF CRC calculation.");
 120 MODULE_LICENSE("GPL");
 121 MODULE_ALIAS_CRYPTO("crct10dif");
 122 MODULE_ALIAS_CRYPTO("crct10dif-generic");