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1 | // SPDX-License-Identifier: GPL-2.0-or-later | |
2 | /* | |
3 | * CRC32C | |
4 | *@Article{castagnoli-crc, | |
5 | * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman}, | |
6 | * title = {{Optimization of Cyclic Redundancy-Check Codes with 24 | |
7 | * and 32 Parity Bits}}, | |
8 | * journal = IEEE Transactions on Communication, | |
9 | * year = {1993}, | |
10 | * volume = {41}, | |
11 | * number = {6}, | |
12 | * pages = {}, | |
13 | * month = {June}, | |
14 | *} | |
15 | * Used by the iSCSI driver, possibly others, and derived from | |
16 | * the iscsi-crc.c module of the linux-iscsi driver at | |
17 | * http://linux-iscsi.sourceforge.net. | |
18 | * | |
19 | * Following the example of lib/crc32, this function is intended to be | |
20 | * flexible and useful for all users. Modules that currently have their | |
21 | * own crc32c, but hopefully may be able to use this one are: | |
22 | * net/sctp (please add all your doco to here if you change to | |
23 | * use this one!) | |
24 | * <endoflist> | |
25 | * | |
26 | * Copyright (c) 2004 Cisco Systems, Inc. | |
27 | */ | |
28 | ||
29 | #include <crypto/hash.h> | |
30 | #include <linux/err.h> | |
31 | #include <linux/init.h> | |
32 | #include <linux/kernel.h> | |
33 | #include <linux/module.h> | |
34 | #include <linux/crc32c.h> | |
35 | ||
36 | static struct crypto_shash *tfm; | |
37 | ||
38 | u32 crc32c(u32 crc, const void *address, unsigned int length) | |
39 | { | |
40 | SHASH_DESC_ON_STACK(shash, tfm); | |
41 | u32 ret, *ctx = (u32 *)shash_desc_ctx(shash); | |
42 | int err; | |
43 | ||
44 | shash->tfm = tfm; | |
45 | *ctx = crc; | |
46 | ||
47 | err = crypto_shash_update(shash, address, length); | |
48 | BUG_ON(err); | |
49 | ||
50 | ret = *ctx; | |
51 | barrier_data(ctx); | |
52 | return ret; | |
53 | } | |
54 | ||
55 | EXPORT_SYMBOL(crc32c); | |
56 | ||
57 | static int __init libcrc32c_mod_init(void) | |
58 | { | |
59 | tfm = crypto_alloc_shash("crc32c", 0, 0); | |
60 | return PTR_ERR_OR_ZERO(tfm); | |
61 | } | |
62 | ||
63 | static void __exit libcrc32c_mod_fini(void) | |
64 | { | |
65 | crypto_free_shash(tfm); | |
66 | } | |
67 | ||
68 | const char *crc32c_impl(void) | |
69 | { | |
70 | return crypto_shash_driver_name(tfm); | |
71 | } | |
72 | EXPORT_SYMBOL(crc32c_impl); | |
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"); |