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
36static struct crypto_shash *tfm;
37
38u32 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
55EXPORT_SYMBOL(crc32c);
56
57static int __init libcrc32c_mod_init(void)
58{
59	tfm = crypto_alloc_shash("crc32c", 0, 0);
60	return PTR_ERR_OR_ZERO(tfm);
61}
62
63static void __exit libcrc32c_mod_fini(void)
64{
65	crypto_free_shash(tfm);
66}
67
68module_init(libcrc32c_mod_init);
69module_exit(libcrc32c_mod_fini);
70
71MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
72MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
73MODULE_LICENSE("GPL");
74MODULE_SOFTDEP("pre: crc32c");
75