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1da177e4 LT |
1 | /* |
2 | * Cryptographic API. | |
3 | * | |
4 | * CRC32C chksum | |
5 | * | |
6 | * This module file is a wrapper to invoke the lib/crc32c routines. | |
7 | * | |
5773a3e6 HX |
8 | * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au> |
9 | * | |
1da177e4 LT |
10 | * This program is free software; you can redistribute it and/or modify it |
11 | * under the terms of the GNU General Public License as published by the Free | |
12 | * Software Foundation; either version 2 of the License, or (at your option) | |
13 | * any later version. | |
14 | * | |
15 | */ | |
5773a3e6 HX |
16 | |
17 | #include <crypto/internal/hash.h> | |
1da177e4 LT |
18 | #include <linux/init.h> |
19 | #include <linux/module.h> | |
20 | #include <linux/string.h> | |
1da177e4 | 21 | #include <linux/crc32c.h> |
25cdbcd9 | 22 | #include <linux/kernel.h> |
1da177e4 | 23 | |
5773a3e6 | 24 | #define CHKSUM_BLOCK_SIZE 1 |
1da177e4 LT |
25 | #define CHKSUM_DIGEST_SIZE 4 |
26 | ||
27 | struct chksum_ctx { | |
28 | u32 crc; | |
25cdbcd9 | 29 | u32 key; |
1da177e4 LT |
30 | }; |
31 | ||
32 | /* | |
33 | * Steps through buffer one byte at at time, calculates reflected | |
34 | * crc using table. | |
35 | */ | |
36 | ||
6c2bb98b | 37 | static void chksum_init(struct crypto_tfm *tfm) |
1da177e4 | 38 | { |
6c2bb98b | 39 | struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); |
1da177e4 | 40 | |
25cdbcd9 | 41 | mctx->crc = mctx->key; |
1da177e4 LT |
42 | } |
43 | ||
44 | /* | |
45 | * Setting the seed allows arbitrary accumulators and flexible XOR policy | |
46 | * If your algorithm starts with ~0, then XOR with ~0 before you set | |
47 | * the seed. | |
48 | */ | |
6c2bb98b | 49 | static int chksum_setkey(struct crypto_tfm *tfm, const u8 *key, |
560c06ae | 50 | unsigned int keylen) |
1da177e4 | 51 | { |
6c2bb98b | 52 | struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); |
1da177e4 LT |
53 | |
54 | if (keylen != sizeof(mctx->crc)) { | |
560c06ae | 55 | tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; |
1da177e4 LT |
56 | return -EINVAL; |
57 | } | |
25cdbcd9 | 58 | mctx->key = le32_to_cpu(*(__le32 *)key); |
1da177e4 LT |
59 | return 0; |
60 | } | |
61 | ||
6c2bb98b HX |
62 | static void chksum_update(struct crypto_tfm *tfm, const u8 *data, |
63 | unsigned int length) | |
1da177e4 | 64 | { |
6c2bb98b | 65 | struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); |
1da177e4 | 66 | |
25cdbcd9 | 67 | mctx->crc = crc32c(mctx->crc, data, length); |
1da177e4 LT |
68 | } |
69 | ||
6c2bb98b | 70 | static void chksum_final(struct crypto_tfm *tfm, u8 *out) |
1da177e4 | 71 | { |
6c2bb98b | 72 | struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); |
1da177e4 | 73 | |
25cdbcd9 HX |
74 | *(__le32 *)out = ~cpu_to_le32(mctx->crc); |
75 | } | |
76 | ||
5773a3e6 | 77 | static int crc32c_cra_init_old(struct crypto_tfm *tfm) |
25cdbcd9 HX |
78 | { |
79 | struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); | |
80 | ||
81 | mctx->key = ~0; | |
82 | return 0; | |
1da177e4 LT |
83 | } |
84 | ||
5773a3e6 | 85 | static struct crypto_alg old_alg = { |
1da177e4 LT |
86 | .cra_name = "crc32c", |
87 | .cra_flags = CRYPTO_ALG_TYPE_DIGEST, | |
88 | .cra_blocksize = CHKSUM_BLOCK_SIZE, | |
89 | .cra_ctxsize = sizeof(struct chksum_ctx), | |
90 | .cra_module = THIS_MODULE, | |
5773a3e6 HX |
91 | .cra_list = LIST_HEAD_INIT(old_alg.cra_list), |
92 | .cra_init = crc32c_cra_init_old, | |
1da177e4 LT |
93 | .cra_u = { |
94 | .digest = { | |
95 | .dia_digestsize= CHKSUM_DIGEST_SIZE, | |
96 | .dia_setkey = chksum_setkey, | |
97 | .dia_init = chksum_init, | |
98 | .dia_update = chksum_update, | |
99 | .dia_final = chksum_final | |
100 | } | |
101 | } | |
102 | }; | |
103 | ||
5773a3e6 HX |
104 | /* |
105 | * Setting the seed allows arbitrary accumulators and flexible XOR policy | |
106 | * If your algorithm starts with ~0, then XOR with ~0 before you set | |
107 | * the seed. | |
108 | */ | |
109 | static int crc32c_setkey(struct crypto_ahash *hash, const u8 *key, | |
110 | unsigned int keylen) | |
111 | { | |
112 | u32 *mctx = crypto_ahash_ctx(hash); | |
113 | ||
114 | if (keylen != sizeof(u32)) { | |
115 | crypto_ahash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN); | |
116 | return -EINVAL; | |
117 | } | |
118 | *mctx = le32_to_cpup((__le32 *)key); | |
119 | return 0; | |
120 | } | |
121 | ||
122 | static int crc32c_init(struct ahash_request *req) | |
123 | { | |
124 | u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req)); | |
125 | u32 *crcp = ahash_request_ctx(req); | |
126 | ||
127 | *crcp = *mctx; | |
128 | return 0; | |
129 | } | |
130 | ||
131 | static int crc32c_update(struct ahash_request *req) | |
132 | { | |
133 | struct crypto_hash_walk walk; | |
134 | u32 *crcp = ahash_request_ctx(req); | |
135 | u32 crc = *crcp; | |
136 | int nbytes; | |
137 | ||
138 | for (nbytes = crypto_hash_walk_first(req, &walk); nbytes; | |
139 | nbytes = crypto_hash_walk_done(&walk, 0)) | |
140 | crc = crc32c(crc, walk.data, nbytes); | |
141 | ||
142 | *crcp = crc; | |
143 | return 0; | |
144 | } | |
145 | ||
146 | static int crc32c_final(struct ahash_request *req) | |
147 | { | |
148 | u32 *crcp = ahash_request_ctx(req); | |
149 | ||
150 | *(__le32 *)req->result = ~cpu_to_le32p(crcp); | |
151 | return 0; | |
152 | } | |
153 | ||
154 | static int crc32c_digest(struct ahash_request *req) | |
155 | { | |
156 | struct crypto_hash_walk walk; | |
157 | u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req)); | |
158 | u32 crc = *mctx; | |
159 | int nbytes; | |
160 | ||
161 | for (nbytes = crypto_hash_walk_first(req, &walk); nbytes; | |
162 | nbytes = crypto_hash_walk_done(&walk, 0)) | |
163 | crc = crc32c(crc, walk.data, nbytes); | |
164 | ||
165 | *(__le32 *)req->result = ~cpu_to_le32(crc); | |
166 | return 0; | |
167 | } | |
168 | ||
169 | static int crc32c_cra_init(struct crypto_tfm *tfm) | |
170 | { | |
171 | u32 *key = crypto_tfm_ctx(tfm); | |
172 | ||
173 | *key = ~0; | |
174 | ||
175 | tfm->crt_ahash.reqsize = sizeof(u32); | |
176 | ||
177 | return 0; | |
178 | } | |
179 | ||
180 | static struct crypto_alg alg = { | |
181 | .cra_name = "crc32c", | |
182 | .cra_driver_name = "crc32c-generic", | |
183 | .cra_priority = 100, | |
184 | .cra_flags = CRYPTO_ALG_TYPE_AHASH, | |
185 | .cra_blocksize = CHKSUM_BLOCK_SIZE, | |
186 | .cra_alignmask = 3, | |
187 | .cra_ctxsize = sizeof(u32), | |
188 | .cra_module = THIS_MODULE, | |
189 | .cra_list = LIST_HEAD_INIT(alg.cra_list), | |
190 | .cra_init = crc32c_cra_init, | |
191 | .cra_type = &crypto_ahash_type, | |
192 | .cra_u = { | |
193 | .ahash = { | |
194 | .digestsize = CHKSUM_DIGEST_SIZE, | |
195 | .setkey = crc32c_setkey, | |
196 | .init = crc32c_init, | |
197 | .update = crc32c_update, | |
198 | .final = crc32c_final, | |
199 | .digest = crc32c_digest, | |
200 | } | |
201 | } | |
202 | }; | |
203 | ||
3af5b90b | 204 | static int __init crc32c_mod_init(void) |
1da177e4 | 205 | { |
5773a3e6 HX |
206 | int err; |
207 | ||
208 | err = crypto_register_alg(&old_alg); | |
209 | if (err) | |
210 | return err; | |
211 | ||
212 | err = crypto_register_alg(&alg); | |
213 | if (err) | |
214 | crypto_unregister_alg(&old_alg); | |
215 | ||
216 | return err; | |
1da177e4 LT |
217 | } |
218 | ||
3af5b90b | 219 | static void __exit crc32c_mod_fini(void) |
1da177e4 LT |
220 | { |
221 | crypto_unregister_alg(&alg); | |
5773a3e6 | 222 | crypto_unregister_alg(&old_alg); |
1da177e4 LT |
223 | } |
224 | ||
3af5b90b KB |
225 | module_init(crc32c_mod_init); |
226 | module_exit(crc32c_mod_fini); | |
1da177e4 LT |
227 | |
228 | MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>"); | |
229 | MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c"); | |
230 | MODULE_LICENSE("GPL"); |