1/* GPL HEADER START
2 *
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 only,
7 * as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 * General Public License version 2 for more details (a copy is included
13 * in the LICENSE file that accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License
16 * version 2 along with this program; If not, see http://www.gnu.org/licenses
17 *
18 * Please  visit http://www.xyratex.com/contact if you need additional
19 * information or have any questions.
20 *
21 * GPL HEADER END
22 */
23
24/*
25 * Copyright 2012 Xyratex Technology Limited
26 */
27
28/*
29 * This is crypto api shash wrappers to crc32_le.
30 */
31
32#include <asm/unaligned.h>
33#include <linux/crc32.h>
34#include <crypto/internal/hash.h>
35#include <linux/init.h>
36#include <linux/module.h>
37#include <linux/string.h>
38#include <linux/kernel.h>
39
40#define CHKSUM_BLOCK_SIZE	1
41#define CHKSUM_DIGEST_SIZE	4
42
43/** No default init with ~0 */
44static int crc32_cra_init(struct crypto_tfm *tfm)
45{
46	u32 *key = crypto_tfm_ctx(tfm);
47
48	*key = 0;
49
50	return 0;
51}
52
53/*
54 * Setting the seed allows arbitrary accumulators and flexible XOR policy
55 * If your algorithm starts with ~0, then XOR with ~0 before you set
56 * the seed.
57 */
58static int crc32_setkey(struct crypto_shash *hash, const u8 *key,
59			unsigned int keylen)
60{
61	u32 *mctx = crypto_shash_ctx(hash);
62
63	if (keylen != sizeof(u32))
64		return -EINVAL;
65	*mctx = get_unaligned_le32(key);
66	return 0;
67}
68
69static int crc32_init(struct shash_desc *desc)
70{
71	u32 *mctx = crypto_shash_ctx(desc->tfm);
72	u32 *crcp = shash_desc_ctx(desc);
73
74	*crcp = *mctx;
75
76	return 0;
77}
78
79static int crc32_update(struct shash_desc *desc, const u8 *data,
80			unsigned int len)
81{
82	u32 *crcp = shash_desc_ctx(desc);
83
84	*crcp = crc32_le(*crcp, data, len);
85	return 0;
86}
87
88/* No final XOR 0xFFFFFFFF, like crc32_le */
89static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len,
90			 u8 *out)
91{
92	put_unaligned_le32(crc32_le(*crcp, data, len), out);
93	return 0;
94}
95
96static int crc32_finup(struct shash_desc *desc, const u8 *data,
97		       unsigned int len, u8 *out)
98{
99	return __crc32_finup(shash_desc_ctx(desc), data, len, out);
100}
101
102static int crc32_final(struct shash_desc *desc, u8 *out)
103{
104	u32 *crcp = shash_desc_ctx(desc);
105
106	put_unaligned_le32(*crcp, out);
107	return 0;
108}
109
110static int crc32_digest(struct shash_desc *desc, const u8 *data,
111			unsigned int len, u8 *out)
112{
113	return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len,
114			     out);
115}
116static struct shash_alg alg = {
117	.setkey		= crc32_setkey,
118	.init		= crc32_init,
119	.update		= crc32_update,
120	.final		= crc32_final,
121	.finup		= crc32_finup,
122	.digest		= crc32_digest,
123	.descsize	= sizeof(u32),
124	.digestsize	= CHKSUM_DIGEST_SIZE,
125	.base		= {
126		.cra_name		= "crc32",
127		.cra_driver_name	= "crc32-generic",
128		.cra_priority		= 100,
129		.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
130		.cra_blocksize		= CHKSUM_BLOCK_SIZE,
131		.cra_ctxsize		= sizeof(u32),
132		.cra_module		= THIS_MODULE,
133		.cra_init		= crc32_cra_init,
134	}
135};
136
137static int __init crc32_mod_init(void)
138{
139	return crypto_register_shash(&alg);
140}
141
142static void __exit crc32_mod_fini(void)
143{
144	crypto_unregister_shash(&alg);
145}
146
147subsys_initcall(crc32_mod_init);
148module_exit(crc32_mod_fini);
149
150MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>");
151MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32");
152MODULE_LICENSE("GPL");
153MODULE_ALIAS_CRYPTO("crc32");
154MODULE_ALIAS_CRYPTO("crc32-generic");
155