diff options
Diffstat (limited to 'crypto/crc32.c')
| -rw-r--r-- | crypto/crc32.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/crypto/crc32.c b/crypto/crc32.c new file mode 100644 index 0000000..9d1c415 --- /dev/null +++ b/crypto/crc32.c @@ -0,0 +1,158 @@ +/* GPL HEADER START + * + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 only, + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License version 2 for more details (a copy is included + * in the LICENSE file that accompanied this code). + * + * You should have received a copy of the GNU General Public License + * version 2 along with this program; If not, see http://www.gnu.org/licenses + * + * Please visit http://www.xyratex.com/contact if you need additional + * information or have any questions. + * + * GPL HEADER END + */ + +/* + * Copyright 2012 Xyratex Technology Limited + */ + +/* + * This is crypto api shash wrappers to crc32_le. + */ + +#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 + +static u32 __crc32_le(u32 crc, unsigned char const *p, size_t len) +{ + return crc32_le(crc, p, len); +} + +/** 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)) { + crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN); + return -EINVAL; + } + *mctx = le32_to_cpup((__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) +{ + *(__le32 *)out = cpu_to_le32(__crc32_le(*crcp, data, len)); + 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); + + *(__le32 *)out = cpu_to_le32p(crcp); + 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-table", + .cra_priority = 100, + .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); +} + +module_init(crc32_mod_init); +module_exit(crc32_mod_fini); + +MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>"); +MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32"); +MODULE_LICENSE("GPL"); |
