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 the 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 const char *crc32c_impl(void) 69 { 70 return crypto_shash_driver_name(tfm); 71 } 72 EXPORT_SYMBOL(crc32c_impl); 73 74 module_init(libcrc32c_mod_init); 75 module_exit(libcrc32c_mod_fini); 76 77 MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>"); 78 MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations"); 79 MODULE_LICENSE("GPL"); 80 MODULE_SOFTDEP("pre: crc32c"); 81