blob: 9f79547d1b9782237a563f6a2e838655f6adf6dc
1 | /* |
2 | * CRC32C |
3 | *@Article{castagnoli-crc, |
4 | * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman}, |
5 | * title = {{Optimization of Cyclic Redundancy-Check Codes with 24 |
6 | * and 32 Parity Bits}}, |
7 | * journal = IEEE Transactions on Communication, |
8 | * year = {1993}, |
9 | * volume = {41}, |
10 | * number = {6}, |
11 | * pages = {}, |
12 | * month = {June}, |
13 | *} |
14 | * Used by the iSCSI driver, possibly others, and derived from the |
15 | * the iscsi-crc.c module of the linux-iscsi driver at |
16 | * http://linux-iscsi.sourceforge.net. |
17 | * |
18 | * Following the example of lib/crc32, this function is intended to be |
19 | * flexible and useful for all users. Modules that currently have their |
20 | * own crc32c, but hopefully may be able to use this one are: |
21 | * net/sctp (please add all your doco to here if you change to |
22 | * use this one!) |
23 | * <endoflist> |
24 | * |
25 | * Copyright (c) 2004 Cisco Systems, Inc. |
26 | * |
27 | * This program is free software; you can redistribute it and/or modify it |
28 | * under the terms of the GNU General Public License as published by the Free |
29 | * Software Foundation; either version 2 of the License, or (at your option) |
30 | * any later version. |
31 | * |
32 | */ |
33 | |
34 | #include <crypto/hash.h> |
35 | #include <linux/err.h> |
36 | #include <linux/init.h> |
37 | #include <linux/kernel.h> |
38 | #include <linux/module.h> |
39 | #include <linux/crc32c.h> |
40 | |
41 | static struct crypto_shash *tfm; |
42 | |
43 | u32 crc32c(u32 crc, const void *address, unsigned int length) |
44 | { |
45 | SHASH_DESC_ON_STACK(shash, tfm); |
46 | u32 ret, *ctx = (u32 *)shash_desc_ctx(shash); |
47 | int err; |
48 | |
49 | shash->tfm = tfm; |
50 | shash->flags = 0; |
51 | *ctx = crc; |
52 | |
53 | err = crypto_shash_update(shash, address, length); |
54 | BUG_ON(err); |
55 | |
56 | ret = *ctx; |
57 | barrier_data(ctx); |
58 | return ret; |
59 | } |
60 | |
61 | EXPORT_SYMBOL(crc32c); |
62 | |
63 | static int __init libcrc32c_mod_init(void) |
64 | { |
65 | tfm = crypto_alloc_shash("crc32c", 0, 0); |
66 | return PTR_ERR_OR_ZERO(tfm); |
67 | } |
68 | |
69 | static void __exit libcrc32c_mod_fini(void) |
70 | { |
71 | crypto_free_shash(tfm); |
72 | } |
73 | |
74 | module_init(libcrc32c_mod_init); |
75 | module_exit(libcrc32c_mod_fini); |
76 | |
77 | MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>"); |
78 | MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations"); |
79 | MODULE_LICENSE("GPL"); |
80 | MODULE_SOFTDEP("pre: crc32c"); |
81 |