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crc32_generic.c
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crc32_generic.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2012 Xyratex Technology Limited
*/
/*
* This is crypto api shash wrappers to crc32_le.
*/
#include <asm/unaligned.h>
#include <linux/crc32.h>
#include <crypto/internal/hash.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/kernel.h>
#define CHKSUM_BLOCK_SIZE 1
#define CHKSUM_DIGEST_SIZE 4
/** No default init with ~0 */
static int crc32_cra_init(struct crypto_tfm *tfm)
{
u32 *key = crypto_tfm_ctx(tfm);
*key = 0;
return 0;
}
/*
* 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 crc32_setkey(struct crypto_shash *hash, const u8 *key,
unsigned int keylen)
{
u32 *mctx = crypto_shash_ctx(hash);
if (keylen != sizeof(u32))
return -EINVAL;
*mctx = get_unaligned_le32(key);
return 0;
}
static int crc32_init(struct shash_desc *desc)
{
u32 *mctx = crypto_shash_ctx(desc->tfm);
u32 *crcp = shash_desc_ctx(desc);
*crcp = *mctx;
return 0;
}
static int crc32_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
u32 *crcp = shash_desc_ctx(desc);
*crcp = crc32_le(*crcp, data, len);
return 0;
}
/* No final XOR 0xFFFFFFFF, like crc32_le */
static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len,
u8 *out)
{
put_unaligned_le32(crc32_le(*crcp, data, len), out);
return 0;
}
static int crc32_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return __crc32_finup(shash_desc_ctx(desc), data, len, out);
}
static int crc32_final(struct shash_desc *desc, u8 *out)
{
u32 *crcp = shash_desc_ctx(desc);
put_unaligned_le32(*crcp, out);
return 0;
}
static int crc32_digest(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len,
out);
}
static struct shash_alg alg = {
.setkey = crc32_setkey,
.init = crc32_init,
.update = crc32_update,
.final = crc32_final,
.finup = crc32_finup,
.digest = crc32_digest,
.descsize = sizeof(u32),
.digestsize = CHKSUM_DIGEST_SIZE,
.base = {
.cra_name = "crc32",
.cra_driver_name = "crc32-generic",
.cra_priority = 100,
.cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
.cra_blocksize = CHKSUM_BLOCK_SIZE,
.cra_ctxsize = sizeof(u32),
.cra_module = THIS_MODULE,
.cra_init = crc32_cra_init,
}
};
static int __init crc32_mod_init(void)
{
return crypto_register_shash(&alg);
}
static void __exit crc32_mod_fini(void)
{
crypto_unregister_shash(&alg);
}
subsys_initcall(crc32_mod_init);
module_exit(crc32_mod_fini);
MODULE_AUTHOR("Alexander Boyko <[email protected]>");
MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CRYPTO("crc32");
MODULE_ALIAS_CRYPTO("crc32-generic");