Commit | Line | Data |
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db83aabf | 1 | /* |
1da177e4 LT |
2 | * Cryptographic API. |
3 | * | |
4 | * CRC32C chksum | |
5 | * | |
69c35efc HX |
6 | *@Article{castagnoli-crc, |
7 | * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman}, | |
8 | * title = {{Optimization of Cyclic Redundancy-Check Codes with 24 | |
9 | * and 32 Parity Bits}}, | |
10 | * journal = IEEE Transactions on Communication, | |
11 | * year = {1993}, | |
12 | * volume = {41}, | |
13 | * number = {6}, | |
14 | * pages = {}, | |
15 | * month = {June}, | |
16 | *} | |
17 | * Used by the iSCSI driver, possibly others, and derived from the | |
18 | * the iscsi-crc.c module of the linux-iscsi driver at | |
19 | * http://linux-iscsi.sourceforge.net. | |
1da177e4 | 20 | * |
69c35efc HX |
21 | * Following the example of lib/crc32, this function is intended to be |
22 | * flexible and useful for all users. Modules that currently have their | |
23 | * own crc32c, but hopefully may be able to use this one are: | |
24 | * net/sctp (please add all your doco to here if you change to | |
25 | * use this one!) | |
26 | * <endoflist> | |
27 | * | |
28 | * Copyright (c) 2004 Cisco Systems, Inc. | |
5773a3e6 HX |
29 | * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au> |
30 | * | |
1da177e4 LT |
31 | * This program is free software; you can redistribute it and/or modify it |
32 | * under the terms of the GNU General Public License as published by the Free | |
db83aabf | 33 | * Software Foundation; either version 2 of the License, or (at your option) |
1da177e4 LT |
34 | * any later version. |
35 | * | |
36 | */ | |
5773a3e6 HX |
37 | |
38 | #include <crypto/internal/hash.h> | |
1da177e4 LT |
39 | #include <linux/init.h> |
40 | #include <linux/module.h> | |
41 | #include <linux/string.h> | |
25cdbcd9 | 42 | #include <linux/kernel.h> |
6a0962b2 | 43 | #include <linux/crc32.h> |
1da177e4 | 44 | |
5773a3e6 | 45 | #define CHKSUM_BLOCK_SIZE 1 |
1da177e4 LT |
46 | #define CHKSUM_DIGEST_SIZE 4 |
47 | ||
48 | struct chksum_ctx { | |
25cdbcd9 | 49 | u32 key; |
1da177e4 LT |
50 | }; |
51 | ||
faccc4bb HX |
52 | struct chksum_desc_ctx { |
53 | u32 crc; | |
54 | }; | |
55 | ||
1da177e4 | 56 | /* |
db83aabf | 57 | * Steps through buffer one byte at at time, calculates reflected |
1da177e4 LT |
58 | * crc using table. |
59 | */ | |
60 | ||
faccc4bb | 61 | static int chksum_init(struct shash_desc *desc) |
1da177e4 | 62 | { |
faccc4bb HX |
63 | struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm); |
64 | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); | |
65 | ||
66 | ctx->crc = mctx->key; | |
1da177e4 | 67 | |
faccc4bb | 68 | return 0; |
1da177e4 LT |
69 | } |
70 | ||
71 | /* | |
72 | * Setting the seed allows arbitrary accumulators and flexible XOR policy | |
73 | * If your algorithm starts with ~0, then XOR with ~0 before you set | |
74 | * the seed. | |
75 | */ | |
faccc4bb | 76 | static int chksum_setkey(struct crypto_shash *tfm, const u8 *key, |
560c06ae | 77 | unsigned int keylen) |
1da177e4 | 78 | { |
faccc4bb | 79 | struct chksum_ctx *mctx = crypto_shash_ctx(tfm); |
1da177e4 | 80 | |
faccc4bb HX |
81 | if (keylen != sizeof(mctx->key)) { |
82 | crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); | |
1da177e4 LT |
83 | return -EINVAL; |
84 | } | |
25cdbcd9 | 85 | mctx->key = le32_to_cpu(*(__le32 *)key); |
1da177e4 LT |
86 | return 0; |
87 | } | |
88 | ||
faccc4bb HX |
89 | static int chksum_update(struct shash_desc *desc, const u8 *data, |
90 | unsigned int length) | |
1da177e4 | 91 | { |
faccc4bb | 92 | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
1da177e4 | 93 | |
6a0962b2 | 94 | ctx->crc = __crc32c_le(ctx->crc, data, length); |
25cdbcd9 | 95 | return 0; |
1da177e4 LT |
96 | } |
97 | ||
faccc4bb | 98 | static int chksum_final(struct shash_desc *desc, u8 *out) |
5773a3e6 | 99 | { |
faccc4bb | 100 | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
5773a3e6 | 101 | |
faccc4bb | 102 | *(__le32 *)out = ~cpu_to_le32p(&ctx->crc); |
5773a3e6 HX |
103 | return 0; |
104 | } | |
105 | ||
faccc4bb | 106 | static int __chksum_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out) |
5773a3e6 | 107 | { |
6a0962b2 | 108 | *(__le32 *)out = ~cpu_to_le32(__crc32c_le(*crcp, data, len)); |
5773a3e6 HX |
109 | return 0; |
110 | } | |
111 | ||
faccc4bb HX |
112 | static int chksum_finup(struct shash_desc *desc, const u8 *data, |
113 | unsigned int len, u8 *out) | |
5773a3e6 | 114 | { |
faccc4bb | 115 | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
5773a3e6 | 116 | |
faccc4bb | 117 | return __chksum_finup(&ctx->crc, data, len, out); |
5773a3e6 HX |
118 | } |
119 | ||
faccc4bb HX |
120 | static int chksum_digest(struct shash_desc *desc, const u8 *data, |
121 | unsigned int length, u8 *out) | |
5773a3e6 | 122 | { |
faccc4bb | 123 | struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm); |
5773a3e6 | 124 | |
faccc4bb | 125 | return __chksum_finup(&mctx->key, data, length, out); |
5773a3e6 HX |
126 | } |
127 | ||
128 | static int crc32c_cra_init(struct crypto_tfm *tfm) | |
129 | { | |
faccc4bb | 130 | struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); |
5773a3e6 | 131 | |
faccc4bb | 132 | mctx->key = ~0; |
5773a3e6 HX |
133 | return 0; |
134 | } | |
135 | ||
faccc4bb HX |
136 | static struct shash_alg alg = { |
137 | .digestsize = CHKSUM_DIGEST_SIZE, | |
138 | .setkey = chksum_setkey, | |
fae36640 MV |
139 | .init = chksum_init, |
140 | .update = chksum_update, | |
141 | .final = chksum_final, | |
142 | .finup = chksum_finup, | |
143 | .digest = chksum_digest, | |
faccc4bb HX |
144 | .descsize = sizeof(struct chksum_desc_ctx), |
145 | .base = { | |
146 | .cra_name = "crc32c", | |
147 | .cra_driver_name = "crc32c-generic", | |
148 | .cra_priority = 100, | |
149 | .cra_blocksize = CHKSUM_BLOCK_SIZE, | |
150 | .cra_alignmask = 3, | |
151 | .cra_ctxsize = sizeof(struct chksum_ctx), | |
152 | .cra_module = THIS_MODULE, | |
153 | .cra_init = crc32c_cra_init, | |
5773a3e6 HX |
154 | } |
155 | }; | |
156 | ||
3af5b90b | 157 | static int __init crc32c_mod_init(void) |
1da177e4 | 158 | { |
faccc4bb | 159 | return crypto_register_shash(&alg); |
1da177e4 LT |
160 | } |
161 | ||
3af5b90b | 162 | static void __exit crc32c_mod_fini(void) |
1da177e4 | 163 | { |
faccc4bb | 164 | crypto_unregister_shash(&alg); |
1da177e4 LT |
165 | } |
166 | ||
3af5b90b KB |
167 | module_init(crc32c_mod_init); |
168 | module_exit(crc32c_mod_fini); | |
1da177e4 LT |
169 | |
170 | MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>"); | |
171 | MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c"); | |
172 | MODULE_LICENSE("GPL"); | |
5d26a105 | 173 | MODULE_ALIAS_CRYPTO("crc32c"); |
3e14dcf7 | 174 | MODULE_ALIAS_CRYPTO("crc32c-generic"); |