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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
db83aabf | 2 | /* |
1da177e4 LT |
3 | * Cryptographic API. |
4 | * | |
5 | * CRC32C chksum | |
6 | * | |
69c35efc HX |
7 | *@Article{castagnoli-crc, |
8 | * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman}, | |
9 | * title = {{Optimization of Cyclic Redundancy-Check Codes with 24 | |
10 | * and 32 Parity Bits}}, | |
11 | * journal = IEEE Transactions on Communication, | |
12 | * year = {1993}, | |
13 | * volume = {41}, | |
14 | * number = {6}, | |
15 | * pages = {}, | |
16 | * month = {June}, | |
17 | *} | |
743b9150 | 18 | * Used by the iSCSI driver, possibly others, and derived from |
69c35efc HX |
19 | * the iscsi-crc.c module of the linux-iscsi driver at |
20 | * http://linux-iscsi.sourceforge.net. | |
1da177e4 | 21 | * |
69c35efc HX |
22 | * Following the example of lib/crc32, this function is intended to be |
23 | * flexible and useful for all users. Modules that currently have their | |
24 | * own crc32c, but hopefully may be able to use this one are: | |
25 | * net/sctp (please add all your doco to here if you change to | |
26 | * use this one!) | |
27 | * <endoflist> | |
28 | * | |
29 | * Copyright (c) 2004 Cisco Systems, Inc. | |
5773a3e6 | 30 | * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au> |
1da177e4 | 31 | */ |
5773a3e6 | 32 | |
7bcfb136 | 33 | #include <asm/unaligned.h> |
5773a3e6 | 34 | #include <crypto/internal/hash.h> |
1da177e4 LT |
35 | #include <linux/init.h> |
36 | #include <linux/module.h> | |
37 | #include <linux/string.h> | |
25cdbcd9 | 38 | #include <linux/kernel.h> |
6a0962b2 | 39 | #include <linux/crc32.h> |
1da177e4 | 40 | |
5773a3e6 | 41 | #define CHKSUM_BLOCK_SIZE 1 |
1da177e4 LT |
42 | #define CHKSUM_DIGEST_SIZE 4 |
43 | ||
44 | struct chksum_ctx { | |
25cdbcd9 | 45 | u32 key; |
1da177e4 LT |
46 | }; |
47 | ||
faccc4bb HX |
48 | struct chksum_desc_ctx { |
49 | u32 crc; | |
50 | }; | |
51 | ||
1da177e4 | 52 | /* |
743b9150 | 53 | * Steps through buffer one byte at a time, calculates reflected |
1da177e4 LT |
54 | * crc using table. |
55 | */ | |
56 | ||
faccc4bb | 57 | static int chksum_init(struct shash_desc *desc) |
1da177e4 | 58 | { |
faccc4bb HX |
59 | struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm); |
60 | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); | |
61 | ||
62 | ctx->crc = mctx->key; | |
1da177e4 | 63 | |
faccc4bb | 64 | return 0; |
1da177e4 LT |
65 | } |
66 | ||
67 | /* | |
68 | * Setting the seed allows arbitrary accumulators and flexible XOR policy | |
69 | * If your algorithm starts with ~0, then XOR with ~0 before you set | |
70 | * the seed. | |
71 | */ | |
faccc4bb | 72 | static int chksum_setkey(struct crypto_shash *tfm, const u8 *key, |
560c06ae | 73 | unsigned int keylen) |
1da177e4 | 74 | { |
faccc4bb | 75 | struct chksum_ctx *mctx = crypto_shash_ctx(tfm); |
1da177e4 | 76 | |
674f368a | 77 | if (keylen != sizeof(mctx->key)) |
1da177e4 | 78 | return -EINVAL; |
7bcfb136 | 79 | mctx->key = get_unaligned_le32(key); |
1da177e4 LT |
80 | return 0; |
81 | } | |
82 | ||
faccc4bb HX |
83 | static int chksum_update(struct shash_desc *desc, const u8 *data, |
84 | unsigned int length) | |
1da177e4 | 85 | { |
faccc4bb | 86 | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
1da177e4 | 87 | |
6a0962b2 | 88 | ctx->crc = __crc32c_le(ctx->crc, data, length); |
25cdbcd9 | 89 | return 0; |
1da177e4 LT |
90 | } |
91 | ||
faccc4bb | 92 | static int chksum_final(struct shash_desc *desc, u8 *out) |
5773a3e6 | 93 | { |
faccc4bb | 94 | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
5773a3e6 | 95 | |
7bcfb136 | 96 | put_unaligned_le32(~ctx->crc, out); |
5773a3e6 HX |
97 | return 0; |
98 | } | |
99 | ||
faccc4bb | 100 | static int __chksum_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out) |
5773a3e6 | 101 | { |
7bcfb136 | 102 | put_unaligned_le32(~__crc32c_le(*crcp, data, len), out); |
5773a3e6 HX |
103 | return 0; |
104 | } | |
105 | ||
faccc4bb HX |
106 | static int chksum_finup(struct shash_desc *desc, const u8 *data, |
107 | unsigned int len, u8 *out) | |
5773a3e6 | 108 | { |
faccc4bb | 109 | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
5773a3e6 | 110 | |
faccc4bb | 111 | return __chksum_finup(&ctx->crc, data, len, out); |
5773a3e6 HX |
112 | } |
113 | ||
faccc4bb HX |
114 | static int chksum_digest(struct shash_desc *desc, const u8 *data, |
115 | unsigned int length, u8 *out) | |
5773a3e6 | 116 | { |
faccc4bb | 117 | struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm); |
5773a3e6 | 118 | |
faccc4bb | 119 | return __chksum_finup(&mctx->key, data, length, out); |
5773a3e6 HX |
120 | } |
121 | ||
122 | static int crc32c_cra_init(struct crypto_tfm *tfm) | |
123 | { | |
faccc4bb | 124 | struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); |
5773a3e6 | 125 | |
faccc4bb | 126 | mctx->key = ~0; |
5773a3e6 HX |
127 | return 0; |
128 | } | |
129 | ||
faccc4bb HX |
130 | static struct shash_alg alg = { |
131 | .digestsize = CHKSUM_DIGEST_SIZE, | |
132 | .setkey = chksum_setkey, | |
fae36640 MV |
133 | .init = chksum_init, |
134 | .update = chksum_update, | |
135 | .final = chksum_final, | |
136 | .finup = chksum_finup, | |
137 | .digest = chksum_digest, | |
faccc4bb HX |
138 | .descsize = sizeof(struct chksum_desc_ctx), |
139 | .base = { | |
140 | .cra_name = "crc32c", | |
141 | .cra_driver_name = "crc32c-generic", | |
142 | .cra_priority = 100, | |
a208fa8f | 143 | .cra_flags = CRYPTO_ALG_OPTIONAL_KEY, |
faccc4bb | 144 | .cra_blocksize = CHKSUM_BLOCK_SIZE, |
faccc4bb HX |
145 | .cra_ctxsize = sizeof(struct chksum_ctx), |
146 | .cra_module = THIS_MODULE, | |
147 | .cra_init = crc32c_cra_init, | |
5773a3e6 HX |
148 | } |
149 | }; | |
150 | ||
3af5b90b | 151 | static int __init crc32c_mod_init(void) |
1da177e4 | 152 | { |
faccc4bb | 153 | return crypto_register_shash(&alg); |
1da177e4 LT |
154 | } |
155 | ||
3af5b90b | 156 | static void __exit crc32c_mod_fini(void) |
1da177e4 | 157 | { |
faccc4bb | 158 | crypto_unregister_shash(&alg); |
1da177e4 LT |
159 | } |
160 | ||
c4741b23 | 161 | subsys_initcall(crc32c_mod_init); |
3af5b90b | 162 | module_exit(crc32c_mod_fini); |
1da177e4 LT |
163 | |
164 | MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>"); | |
165 | MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c"); | |
166 | MODULE_LICENSE("GPL"); | |
5d26a105 | 167 | MODULE_ALIAS_CRYPTO("crc32c"); |
3e14dcf7 | 168 | MODULE_ALIAS_CRYPTO("crc32c-generic"); |