blob: 74a54b7f25626e8c6d224af2b7384f7dcbf2e72f [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
Herbert Xu69c35ef2008-11-07 15:11:47 +080033
34#include <crypto/hash.h>
35#include <linux/err.h>
36#include <linux/init.h>
37#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070038#include <linux/module.h>
Jean Delvare290e0e02016-01-20 14:58:06 -080039#include <linux/crc32c.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
Herbert Xu69c35ef2008-11-07 15:11:47 +080041static struct crypto_shash *tfm;
42
43u32 crc32c(u32 crc, const void *address, unsigned int length)
44{
Jan-Simon Möllerea0e0de2012-07-02 12:54:28 +020045 SHASH_DESC_ON_STACK(shash, tfm);
46 u32 *ctx = (u32 *)shash_desc_ctx(shash);
Herbert Xu69c35ef2008-11-07 15:11:47 +080047 int err;
48
Jan-Simon Möllerea0e0de2012-07-02 12:54:28 +020049 shash->tfm = tfm;
50 shash->flags = 0;
51 *ctx = crc;
Herbert Xu69c35ef2008-11-07 15:11:47 +080052
Jan-Simon Möllerea0e0de2012-07-02 12:54:28 +020053 err = crypto_shash_update(shash, address, length);
Herbert Xu69c35ef2008-11-07 15:11:47 +080054 BUG_ON(err);
55
Jan-Simon Möllerea0e0de2012-07-02 12:54:28 +020056 return *ctx;
Herbert Xu69c35ef2008-11-07 15:11:47 +080057}
58
Adrian-Ken Rueegsegger53b146a2008-11-11 12:14:00 +080059EXPORT_SYMBOL(crc32c);
60
Herbert Xu69c35ef2008-11-07 15:11:47 +080061static int __init libcrc32c_mod_init(void)
62{
63 tfm = crypto_alloc_shash("crc32c", 0, 0);
Fabian Frederickf8eaf292014-06-04 16:11:51 -070064 return PTR_ERR_OR_ZERO(tfm);
Herbert Xu69c35ef2008-11-07 15:11:47 +080065}
66
67static void __exit libcrc32c_mod_fini(void)
68{
69 crypto_free_shash(tfm);
70}
71
72module_init(libcrc32c_mod_init);
73module_exit(libcrc32c_mod_fini);
74
Linus Torvalds1da177e2005-04-16 15:20:36 -070075MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
76MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
77MODULE_LICENSE("GPL");
Jean Delvarefd7f6722016-01-18 17:06:05 +010078MODULE_SOFTDEP("pre: crc32c");