projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 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 | */ | |
| 1da177e4 | 33 | |
| 69c35efc HX |
34 | #include <crypto/hash.h> |
| 35 | #include <linux/err.h> | |
| 36 | #include <linux/init.h> | |
| 37 | #include <linux/kernel.h> | |
| 38 | #include <linux/module.h> | |
| 1da177e4 | 39 | |
| 69c35efc | 40 | static struct crypto_shash *tfm; |
| 1da177e4 | 41 | |
| 69c35efc | 42 | u32 crc32c(u32 crc, const void *address, unsigned int length) |
| 1da177e4 | 43 | { |
| 69c35efc HX |
44 | struct { |
| 45 | struct shash_desc shash; | |
| 46 | char ctx[crypto_shash_descsize(tfm)]; | |
| 47 | } desc; | |
| 48 | int err; | |
| 1da177e4 | 49 | |
| 69c35efc HX |
50 | desc.shash.tfm = tfm; |
| 51 | desc.shash.flags = 0; | |
| 52 | *(u32 *)desc.ctx = crc; | |
| 1da177e4 | 53 | |
| 69c35efc HX |
54 | err = crypto_shash_update(&desc.shash, address, length); |
| 55 | BUG_ON(err); | |
| 1da177e4 | 56 | |
| 69c35efc HX |
57 | return *(u32 *)desc.ctx; |
| 58 | } | |
| 1da177e4 | 59 | |
| 53b146ae AKR |
60 | EXPORT_SYMBOL(crc32c); |
| 61 | ||
| 69c35efc | 62 | static int __init libcrc32c_mod_init(void) |
| 1da177e4 | 63 | { |
| 69c35efc | 64 | tfm = crypto_alloc_shash("crc32c", 0, 0); |
| f8eaf298 | 65 | return PTR_ERR_OR_ZERO(tfm); |
| 1da177e4 LT |
66 | } |
| 67 | ||
| 69c35efc | 68 | static void __exit libcrc32c_mod_fini(void) |
| 1da177e4 | 69 | { |
| 69c35efc | 70 | crypto_free_shash(tfm); |
| 1da177e4 | 71 | } |
| 1da177e4 | 72 | |
| 69c35efc HX |
73 | module_init(libcrc32c_mod_init); |
| 74 | module_exit(libcrc32c_mod_fini); | |
| 75 | ||
| 76 | MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>"); | |
| 77 | MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations"); | |
| 78 | MODULE_LICENSE("GPL"); |