/*  * CRC32C *@Article{castagnoli-crc, * author =       { Guy Castagnoli and Stefan Braeuer and Martin Herrman}, * title =        {{Optimization of Cyclic Redundancy-Check Codes with 24 *                 and 32 Parity Bits}}, * journal =      IEEE Transactions on Communication, * year =         {1993}, * volume =       {41}, * number =       {6}, * pages =        {}, * month =        {June}, *} * Used by the iSCSI driver, possibly others, and derived from the * the iscsi-crc.c module of the linux-iscsi driver at * http://linux-iscsi.sourceforge.net. * * Following the example of lib/crc32, this function is intended to be * flexible and useful for all users.  Modules that currently have their * own crc32c, but hopefully may be able to use this one are: *  net/sctp (please add all your doco to here if you change to *            use this one!) *  <endoflist> * * Copyright (c) 2004 Cisco Systems, Inc. *  * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2 of the License, or (at your option)  * any later version. * */ #include <crypto/hash.h>#include <linux/err.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/module.h> static struct crypto_shash *tfm; u32 crc32c(u32 crc, const void *address, unsigned int length){	struct {		struct shash_desc shash;		char ctx[crypto_shash_descsize(tfm)];	} desc;	int err; 	desc.shash.tfm = tfm;	desc.shash.flags = 0;	*(u32 *)desc.ctx = crc; 	err = crypto_shash_update(&desc.shash, address, length);	BUG_ON(err); 	return *(u32 *)desc.ctx;} EXPORT_SYMBOL(crc32c); static int __init libcrc32c_mod_init(void){	tfm = crypto_alloc_shash("crc32c", 0, 0);	if (IS_ERR(tfm))		return PTR_ERR(tfm); 	return 0;} static void __exit libcrc32c_mod_fini(void){	crypto_free_shash(tfm);} module_init(libcrc32c_mod_init);module_exit(libcrc32c_mod_fini); MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");MODULE_LICENSE("GPL");