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 a time, calculates reflected
39  * crc using table.
40  */
41 
chksum_init(struct shash_desc * desc)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 
chksum_update(struct shash_desc * desc,const u8 * data,unsigned int length)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 
chksum_final(struct shash_desc * desc,u8 * out)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 
__chksum_finup(__u16 crc,const u8 * data,unsigned int len,u8 * out)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 
chksum_finup(struct shash_desc * desc,const u8 * data,unsigned int len,u8 * out)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 
chksum_digest(struct shash_desc * desc,const u8 * data,unsigned int length,u8 * out)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 
crct10dif_mod_init(void)105 static int __init crct10dif_mod_init(void)
106 {
107 	return crypto_register_shash(&alg);
108 }
109 
crct10dif_mod_fini(void)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");
123