Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/crypto/crc32c.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 2437 byte(s)
Tag kernel26-2.6.12-alx-r9
1 | /* |
2 | * Cryptographic API. |
3 | * |
4 | * CRC32C chksum |
5 | * |
6 | * This module file is a wrapper to invoke the lib/crc32c routines. |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify it |
9 | * under the terms of the GNU General Public License as published by the Free |
10 | * Software Foundation; either version 2 of the License, or (at your option) |
11 | * any later version. |
12 | * |
13 | */ |
14 | #include <linux/init.h> |
15 | #include <linux/module.h> |
16 | #include <linux/string.h> |
17 | #include <linux/crypto.h> |
18 | #include <linux/crc32c.h> |
19 | #include <asm/byteorder.h> |
20 | |
21 | #define CHKSUM_BLOCK_SIZE 32 |
22 | #define CHKSUM_DIGEST_SIZE 4 |
23 | |
24 | struct chksum_ctx { |
25 | u32 crc; |
26 | }; |
27 | |
28 | /* |
29 | * Steps through buffer one byte at at time, calculates reflected |
30 | * crc using table. |
31 | */ |
32 | |
33 | static void chksum_init(void *ctx) |
34 | { |
35 | struct chksum_ctx *mctx = ctx; |
36 | |
37 | mctx->crc = ~(u32)0; /* common usage */ |
38 | } |
39 | |
40 | /* |
41 | * Setting the seed allows arbitrary accumulators and flexible XOR policy |
42 | * If your algorithm starts with ~0, then XOR with ~0 before you set |
43 | * the seed. |
44 | */ |
45 | static int chksum_setkey(void *ctx, const u8 *key, unsigned int keylen, |
46 | u32 *flags) |
47 | { |
48 | struct chksum_ctx *mctx = ctx; |
49 | |
50 | if (keylen != sizeof(mctx->crc)) { |
51 | if (flags) |
52 | *flags = CRYPTO_TFM_RES_BAD_KEY_LEN; |
53 | return -EINVAL; |
54 | } |
55 | mctx->crc = __cpu_to_le32(*(u32 *)key); |
56 | return 0; |
57 | } |
58 | |
59 | static void chksum_update(void *ctx, const u8 *data, unsigned int length) |
60 | { |
61 | struct chksum_ctx *mctx = ctx; |
62 | u32 mcrc; |
63 | |
64 | mcrc = crc32c(mctx->crc, data, (size_t)length); |
65 | |
66 | mctx->crc = mcrc; |
67 | } |
68 | |
69 | static void chksum_final(void *ctx, u8 *out) |
70 | { |
71 | struct chksum_ctx *mctx = ctx; |
72 | u32 mcrc = (mctx->crc ^ ~(u32)0); |
73 | |
74 | *(u32 *)out = __le32_to_cpu(mcrc); |
75 | } |
76 | |
77 | static struct crypto_alg alg = { |
78 | .cra_name = "crc32c", |
79 | .cra_flags = CRYPTO_ALG_TYPE_DIGEST, |
80 | .cra_blocksize = CHKSUM_BLOCK_SIZE, |
81 | .cra_ctxsize = sizeof(struct chksum_ctx), |
82 | .cra_module = THIS_MODULE, |
83 | .cra_list = LIST_HEAD_INIT(alg.cra_list), |
84 | .cra_u = { |
85 | .digest = { |
86 | .dia_digestsize= CHKSUM_DIGEST_SIZE, |
87 | .dia_setkey = chksum_setkey, |
88 | .dia_init = chksum_init, |
89 | .dia_update = chksum_update, |
90 | .dia_final = chksum_final |
91 | } |
92 | } |
93 | }; |
94 | |
95 | static int __init init(void) |
96 | { |
97 | return crypto_register_alg(&alg); |
98 | } |
99 | |
100 | static void __exit fini(void) |
101 | { |
102 | crypto_unregister_alg(&alg); |
103 | } |
104 | |
105 | module_init(init); |
106 | module_exit(fini); |
107 | |
108 | MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>"); |
109 | MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c"); |
110 | MODULE_LICENSE("GPL"); |