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 *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
  75 static 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
  83 static 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
  91 static 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
 108 static int __init crct10dif_mod_init(void)
 109 {
 110         int ret;
 111
 112         ret = crypto_register_shash(&alg);
 113         return ret;
 114 }
 115
 116 static void __exit crct10dif_mod_fini(void)
 117 {
 118         crypto_unregister_shash(&alg);
 119 }
 120
 121 module_init(crct10dif_mod_init);
 122 module_exit(crct10dif_mod_fini);
 123
 124 MODULE_AUTHOR("Tim Chen <tim.c.chen@linux.intel.com>");
 125 MODULE_DESCRIPTION("T10 DIF CRC calculation.");
 126 MODULE_LICENSE("GPL");
 127 MODULE_ALIAS_CRYPTO("crct10dif");