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 a 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 crc, const u8 *data, unsigned int len, u8 *out)
69{
70	*(__u16 *)out = crc_t10dif_generic(crc, data, len);
71	return 0;
72}
73
74static 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
82static 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
88static 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
105static int __init crct10dif_mod_init(void)
106{
107	return crypto_register_shash(&alg);
108}
109
110static void __exit crct10dif_mod_fini(void)
111{
112	crypto_unregister_shash(&alg);
113}
114
115subsys_initcall(crct10dif_mod_init);
116module_exit(crct10dif_mod_fini);
117
118MODULE_AUTHOR("Tim Chen <tim.c.chen@linux.intel.com>");
119MODULE_DESCRIPTION("T10 DIF CRC calculation.");
120MODULE_LICENSE("GPL");
121MODULE_ALIAS_CRYPTO("crct10dif");
122MODULE_ALIAS_CRYPTO("crct10dif-generic");
123