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 module_init(libcrc32c_mod_init);
69 module_exit(libcrc32c_mod_fini);
70
71 MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
72 MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
73 MODULE_LICENSE("GPL");
74 MODULE_SOFTDEP("pre: crc32c");
75
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