6 * This module file is a wrapper to invoke the lib/crc32c routines.
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the Free
10 * Software Foundation; either version 2 of the License, or (at your option)
14 #include <linux/init.h>
15 #include <linux/module.h>
16 #include <linux/string.h>
17 #include <linux/crypto.h>
18 #include <linux/crc32c.h>
19 #include <linux/kernel.h>
21 #define CHKSUM_BLOCK_SIZE 32
22 #define CHKSUM_DIGEST_SIZE 4
30 * Steps through buffer one byte at at time, calculates reflected
34 static void chksum_init(struct crypto_tfm *tfm)
36 struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
38 mctx->crc = mctx->key;
42 * Setting the seed allows arbitrary accumulators and flexible XOR policy
43 * If your algorithm starts with ~0, then XOR with ~0 before you set
46 static int chksum_setkey(struct crypto_tfm *tfm, const u8 *key,
47 unsigned int keylen, u32 *flags)
49 struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
51 if (keylen != sizeof(mctx->crc)) {
53 *flags = CRYPTO_TFM_RES_BAD_KEY_LEN;
56 mctx->key = le32_to_cpu(*(__le32 *)key);
60 static void chksum_update(struct crypto_tfm *tfm, const u8 *data,
63 struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
65 mctx->crc = crc32c(mctx->crc, data, length);
68 static void chksum_final(struct crypto_tfm *tfm, u8 *out)
70 struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
72 *(__le32 *)out = ~cpu_to_le32(mctx->crc);
75 static int crc32c_cra_init(struct crypto_tfm *tfm)
77 struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
83 static struct crypto_alg alg = {
85 .cra_flags = CRYPTO_ALG_TYPE_DIGEST,
86 .cra_blocksize = CHKSUM_BLOCK_SIZE,
87 .cra_ctxsize = sizeof(struct chksum_ctx),
88 .cra_module = THIS_MODULE,
89 .cra_list = LIST_HEAD_INIT(alg.cra_list),
90 .cra_init = crc32c_cra_init,
93 .dia_digestsize= CHKSUM_DIGEST_SIZE,
94 .dia_setkey = chksum_setkey,
95 .dia_init = chksum_init,
96 .dia_update = chksum_update,
97 .dia_final = chksum_final
102 static int __init init(void)
104 return crypto_register_alg(&alg);
107 static void __exit fini(void)
109 crypto_unregister_alg(&alg);
115 MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
116 MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
117 MODULE_LICENSE("GPL");