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(desc: shash); |
42 | int err; |
43 | |
44 | shash->tfm = tfm; |
45 | *ctx = crc; |
46 | |
47 | err = crypto_shash_update(desc: shash, data: address, len: 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(alg_name: "crc32c" , type: 0, mask: 0); |
60 | return PTR_ERR_OR_ZERO(ptr: 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 | |