blob: 718cbce8d1695f5a3c064fb7ab5618b6fe5c4e28
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 <linux/crc32.h> |
33 | #include <crypto/internal/hash.h> |
34 | #include <linux/init.h> |
35 | #include <linux/module.h> |
36 | #include <linux/string.h> |
37 | #include <linux/kernel.h> |
38 | |
39 | #define CHKSUM_BLOCK_SIZE 1 |
40 | #define CHKSUM_DIGEST_SIZE 4 |
41 | |
42 | static u32 __crc32_le(u32 crc, unsigned char const *p, size_t len) |
43 | { |
44 | return crc32_le(crc, p, len); |
45 | } |
46 | |
47 | /** No default init with ~0 */ |
48 | static int crc32_cra_init(struct crypto_tfm *tfm) |
49 | { |
50 | u32 *key = crypto_tfm_ctx(tfm); |
51 | |
52 | *key = 0; |
53 | |
54 | return 0; |
55 | } |
56 | |
57 | |
58 | /* |
59 | * Setting the seed allows arbitrary accumulators and flexible XOR policy |
60 | * If your algorithm starts with ~0, then XOR with ~0 before you set |
61 | * the seed. |
62 | */ |
63 | static int crc32_setkey(struct crypto_shash *hash, const u8 *key, |
64 | unsigned int keylen) |
65 | { |
66 | u32 *mctx = crypto_shash_ctx(hash); |
67 | |
68 | if (keylen != sizeof(u32)) { |
69 | crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN); |
70 | return -EINVAL; |
71 | } |
72 | *mctx = le32_to_cpup((__le32 *)key); |
73 | return 0; |
74 | } |
75 | |
76 | static int crc32_init(struct shash_desc *desc) |
77 | { |
78 | u32 *mctx = crypto_shash_ctx(desc->tfm); |
79 | u32 *crcp = shash_desc_ctx(desc); |
80 | |
81 | *crcp = *mctx; |
82 | |
83 | return 0; |
84 | } |
85 | |
86 | static int crc32_update(struct shash_desc *desc, const u8 *data, |
87 | unsigned int len) |
88 | { |
89 | u32 *crcp = shash_desc_ctx(desc); |
90 | |
91 | *crcp = __crc32_le(*crcp, data, len); |
92 | return 0; |
93 | } |
94 | |
95 | /* No final XOR 0xFFFFFFFF, like crc32_le */ |
96 | static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len, |
97 | u8 *out) |
98 | { |
99 | *(__le32 *)out = cpu_to_le32(__crc32_le(*crcp, data, len)); |
100 | return 0; |
101 | } |
102 | |
103 | static int crc32_finup(struct shash_desc *desc, const u8 *data, |
104 | unsigned int len, u8 *out) |
105 | { |
106 | return __crc32_finup(shash_desc_ctx(desc), data, len, out); |
107 | } |
108 | |
109 | static int crc32_final(struct shash_desc *desc, u8 *out) |
110 | { |
111 | u32 *crcp = shash_desc_ctx(desc); |
112 | |
113 | *(__le32 *)out = cpu_to_le32p(crcp); |
114 | return 0; |
115 | } |
116 | |
117 | static int crc32_digest(struct shash_desc *desc, const u8 *data, |
118 | unsigned int len, u8 *out) |
119 | { |
120 | return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len, |
121 | out); |
122 | } |
123 | static struct shash_alg alg = { |
124 | .setkey = crc32_setkey, |
125 | .init = crc32_init, |
126 | .update = crc32_update, |
127 | .final = crc32_final, |
128 | .finup = crc32_finup, |
129 | .digest = crc32_digest, |
130 | .descsize = sizeof(u32), |
131 | .digestsize = CHKSUM_DIGEST_SIZE, |
132 | .base = { |
133 | .cra_name = "crc32", |
134 | .cra_driver_name = "crc32-generic", |
135 | .cra_priority = 100, |
136 | .cra_flags = CRYPTO_ALG_OPTIONAL_KEY, |
137 | .cra_blocksize = CHKSUM_BLOCK_SIZE, |
138 | .cra_ctxsize = sizeof(u32), |
139 | .cra_module = THIS_MODULE, |
140 | .cra_init = crc32_cra_init, |
141 | } |
142 | }; |
143 | |
144 | static int __init crc32_mod_init(void) |
145 | { |
146 | return crypto_register_shash(&alg); |
147 | } |
148 | |
149 | static void __exit crc32_mod_fini(void) |
150 | { |
151 | crypto_unregister_shash(&alg); |
152 | } |
153 | |
154 | module_init(crc32_mod_init); |
155 | module_exit(crc32_mod_fini); |
156 | |
157 | MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>"); |
158 | MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32"); |
159 | MODULE_LICENSE("GPL"); |
160 | MODULE_ALIAS_CRYPTO("crc32"); |
161 | MODULE_ALIAS_CRYPTO("crc32-generic"); |
162 |