linux/crypto/crc32c_generic.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Cryptographic API.
 *
 * CRC32C chksum
 *
 *@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 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.
 * Copyright (c) 2008 Herbert Xu <[email protected]>
 */

#include <asm/unaligned.h>
#include <crypto/internal/hash.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/crc32.h>

#define CHKSUM_BLOCK_SIZE …
#define CHKSUM_DIGEST_SIZE …

struct chksum_ctx { … };

struct chksum_desc_ctx { … };

/*
 * Steps through buffer one byte at a time, calculates reflected
 * crc using table.
 */

static int chksum_init(struct shash_desc *desc)
{ … }

/*
 * Setting the seed allows arbitrary accumulators and flexible XOR policy
 * If your algorithm starts with ~0, then XOR with ~0 before you set
 * the seed.
 */
static int chksum_setkey(struct crypto_shash *tfm, const u8 *key,
			 unsigned int keylen)
{ … }

static int chksum_update(struct shash_desc *desc, const u8 *data,
			 unsigned int length)
{ … }

static int chksum_final(struct shash_desc *desc, u8 *out)
{ … }

static int __chksum_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out)
{ … }

static int chksum_finup(struct shash_desc *desc, const u8 *data,
			unsigned int len, u8 *out)
{ … }

static int chksum_digest(struct shash_desc *desc, const u8 *data,
			 unsigned int length, u8 *out)
{ … }

static int crc32c_cra_init(struct crypto_tfm *tfm)
{ … }

static struct shash_alg alg = …;

static int __init crc32c_mod_init(void)
{ … }

static void __exit crc32c_mod_fini(void)
{ … }

subsys_initcall(crc32c_mod_init);
module_exit(crc32c_mod_fini);

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;
MODULE_ALIAS_CRYPTO(…) …;
MODULE_ALIAS_CRYPTO(…) …;