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 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
65 return -EINVAL;
66 }
67 *mctx = get_unaligned_le32(key);
68 return 0;
69}
70
71static int crc32_init(struct shash_desc *desc)
72{
73 u32 *mctx = crypto_shash_ctx(desc->tfm);
74 u32 *crcp = shash_desc_ctx(desc);
75
76 *crcp = *mctx;
77
78 return 0;
79}
80
81static int crc32_update(struct shash_desc *desc, const u8 *data,
82 unsigned int len)
83{
84 u32 *crcp = shash_desc_ctx(desc);
85
86 *crcp = crc32_le(*crcp, data, len);
87 return 0;
88}
89
90/* No final XOR 0xFFFFFFFF, like crc32_le */
91static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len,
92 u8 *out)
93{
94 put_unaligned_le32(crc32_le(*crcp, data, len), out);
95 return 0;
96}
97
98static int crc32_finup(struct shash_desc *desc, const u8 *data,
99 unsigned int len, u8 *out)
100{
101 return __crc32_finup(shash_desc_ctx(desc), data, len, out);
102}
103
104static int crc32_final(struct shash_desc *desc, u8 *out)
105{
106 u32 *crcp = shash_desc_ctx(desc);
107
108 put_unaligned_le32(*crcp, out);
109 return 0;
110}
111
112static int crc32_digest(struct shash_desc *desc, const u8 *data,
113 unsigned int len, u8 *out)
114{
115 return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len,
116 out);
117}
118static struct shash_alg alg = {
119 .setkey = crc32_setkey,
120 .init = crc32_init,
121 .update = crc32_update,
122 .final = crc32_final,
123 .finup = crc32_finup,
124 .digest = crc32_digest,
125 .descsize = sizeof(u32),
126 .digestsize = CHKSUM_DIGEST_SIZE,
127 .base = {
128 .cra_name = "crc32",
129 .cra_driver_name = "crc32-generic",
130 .cra_priority = 100,
131 .cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
132 .cra_blocksize = CHKSUM_BLOCK_SIZE,
133 .cra_ctxsize = sizeof(u32),
134 .cra_module = THIS_MODULE,
135 .cra_init = crc32_cra_init,
136 }
137};
138
139static int __init crc32_mod_init(void)
140{
141 return crypto_register_shash(&alg);
142}
143
144static void __exit crc32_mod_fini(void)
145{
146 crypto_unregister_shash(&alg);
147}
148
149module_init(crc32_mod_init);
150module_exit(crc32_mod_fini);
151
152MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>");
153MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32");
154MODULE_LICENSE("GPL");
155MODULE_ALIAS_CRYPTO("crc32");
156MODULE_ALIAS_CRYPTO("crc32-generic");
157