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 */
crc32_cra_init(struct crypto_tfm * tfm)44 static 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  */
crc32_setkey(struct crypto_shash * hash,const u8 * key,unsigned int keylen)58 static 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 
crc32_init(struct shash_desc * desc)69 static 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 
crc32_update(struct shash_desc * desc,const u8 * data,unsigned int len)79 static 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 */
__crc32_finup(u32 * crcp,const u8 * data,unsigned int len,u8 * out)89 static 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 
crc32_finup(struct shash_desc * desc,const u8 * data,unsigned int len,u8 * out)96 static 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 
crc32_final(struct shash_desc * desc,u8 * out)102 static 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 
crc32_digest(struct shash_desc * desc,const u8 * data,unsigned int len,u8 * out)110 static 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 }
116 static 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 
crc32_mod_init(void)137 static int __init crc32_mod_init(void)
138 {
139 	return crypto_register_shash(&alg);
140 }
141 
crc32_mod_fini(void)142 static void __exit crc32_mod_fini(void)
143 {
144 	crypto_unregister_shash(&alg);
145 }
146 
147 subsys_initcall(crc32_mod_init);
148 module_exit(crc32_mod_fini);
149 
150 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>");
151 MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32");
152 MODULE_LICENSE("GPL");
153 MODULE_ALIAS_CRYPTO("crc32");
154 MODULE_ALIAS_CRYPTO("crc32-generic");
155