kernel26-2.6.12-alx-r9/crypto/crc32c.c

/* 
 * Cryptographic API.
 *
 * CRC32C chksum
 *
 * This module file is a wrapper to invoke the lib/crc32c routines.
 *
 * 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 <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/crypto.h>
#include <linux/crc32c.h>
#include <asm/byteorder.h>

#define CHKSUM_BLOCK_SIZE	32
#define CHKSUM_DIGEST_SIZE	4

struct chksum_ctx {
	u32 crc;
};

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

static void chksum_init(void *ctx)
{
	struct chksum_ctx *mctx = ctx;

	mctx->crc = ~(u32)0;			/* common usage */
}

/*
 * 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(void *ctx, const u8 *key, unsigned int keylen,
	                  u32 *flags)
{
	struct chksum_ctx *mctx = ctx;

	if (keylen != sizeof(mctx->crc)) {
		if (flags)
			*flags = CRYPTO_TFM_RES_BAD_KEY_LEN;
		return -EINVAL;
	}
	mctx->crc = __cpu_to_le32(*(u32 *)key);
	return 0;
}

static void chksum_update(void *ctx, const u8 *data, unsigned int length)
{
	struct chksum_ctx *mctx = ctx;
	u32 mcrc;

	mcrc = crc32c(mctx->crc, data, (size_t)length);

	mctx->crc = mcrc;
}

static void chksum_final(void *ctx, u8 *out)
{
	struct chksum_ctx *mctx = ctx;
	u32 mcrc = (mctx->crc ^ ~(u32)0);
	
	*(u32 *)out = __le32_to_cpu(mcrc);
}

static struct crypto_alg alg = {
	.cra_name	=	"crc32c",
	.cra_flags	=	CRYPTO_ALG_TYPE_DIGEST,
	.cra_blocksize	=	CHKSUM_BLOCK_SIZE,
	.cra_ctxsize	=	sizeof(struct chksum_ctx),
	.cra_module	=	THIS_MODULE,
	.cra_list	=	LIST_HEAD_INIT(alg.cra_list),
	.cra_u		=	{
		.digest = {
			 .dia_digestsize=	CHKSUM_DIGEST_SIZE,
			 .dia_setkey	=	chksum_setkey,
			 .dia_init   	= 	chksum_init,
			 .dia_update 	=	chksum_update,
			 .dia_final  	=	chksum_final
		 }
	}
};

static int __init init(void)
{
	return crypto_register_alg(&alg);
}

static void __exit fini(void)
{
	crypto_unregister_alg(&alg);
}

module_init(init);
module_exit(fini);

MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
MODULE_LICENSE("GPL");
1	/*
2	* Cryptographic API.
3	*
4	* CRC32C chksum
5	*
6	* This module file is a wrapper to invoke the lib/crc32c routines.
7	*
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)
11	* any later version.
12	*
13	*/
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 <asm/byteorder.h>
20
21	#define CHKSUM_BLOCK_SIZE 32
22	#define CHKSUM_DIGEST_SIZE 4
23
24	struct chksum_ctx {
25	u32 crc;
26	};
27
28	/*
29	* Steps through buffer one byte at at time, calculates reflected
30	* crc using table.
31	*/
32
33	static void chksum_init(void *ctx)
34	{
35	struct chksum_ctx *mctx = ctx;
36
37	mctx->crc = ~(u32)0; /* common usage */
38	}
39
40	/*
41	* Setting the seed allows arbitrary accumulators and flexible XOR policy
42	* If your algorithm starts with ~0, then XOR with ~0 before you set
43	* the seed.
44	*/
45	static int chksum_setkey(void ctx, const u8 key, unsigned int keylen,
46	u32 *flags)
47	{
48	struct chksum_ctx *mctx = ctx;
49
50	if (keylen != sizeof(mctx->crc)) {
51	if (flags)
52	*flags = CRYPTO_TFM_RES_BAD_KEY_LEN;
53	return -EINVAL;
54	}
55	mctx->crc = __cpu_to_le32((u32 )key);
56	return 0;
57	}
58
59	static void chksum_update(void ctx, const u8 data, unsigned int length)
60	{
61	struct chksum_ctx *mctx = ctx;
62	u32 mcrc;
63
64	mcrc = crc32c(mctx->crc, data, (size_t)length);
65
66	mctx->crc = mcrc;
67	}
68
69	static void chksum_final(void ctx, u8 out)
70	{
71	struct chksum_ctx *mctx = ctx;
72	u32 mcrc = (mctx->crc ^ ~(u32)0);
73
74	(u32 )out = __le32_to_cpu(mcrc);
75	}
76
77	static struct crypto_alg alg = {
78	.cra_name = "crc32c",
79	.cra_flags = CRYPTO_ALG_TYPE_DIGEST,
80	.cra_blocksize = CHKSUM_BLOCK_SIZE,
81	.cra_ctxsize = sizeof(struct chksum_ctx),
82	.cra_module = THIS_MODULE,
83	.cra_list = LIST_HEAD_INIT(alg.cra_list),
84	.cra_u = {
85	.digest = {
86	.dia_digestsize= CHKSUM_DIGEST_SIZE,
87	.dia_setkey = chksum_setkey,
88	.dia_init = chksum_init,
89	.dia_update = chksum_update,
90	.dia_final = chksum_final
91	}
92	}
93	};
94
95	static int __init init(void)
96	{
97	return crypto_register_alg(&alg);
98	}
99
100	static void __exit fini(void)
101	{
102	crypto_unregister_alg(&alg);
103	}
104
105	module_init(init);
106	module_exit(fini);
107
108	MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
109	MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
110	MODULE_LICENSE("GPL");