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/*

 * Cryptographic API.

 *

 * Null algorithms, aka Much Ado About Nothing.

 *

 * These are needed for IPsec, and may be useful in general for

 * testing & debugging.

 *

 * The null cipher is compliant with RFC2410.

 *

 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>

 *

 * 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/mm.h>

#include <asm/scatterlist.h>

#include <linux/crypto.h>

#define NULL_KEY_SIZE           0

#define NULL_BLOCK_SIZE         1

#define NULL_DIGEST_SIZE        0

static int null_compress(void *ctx, const u8 *src, unsigned int slen,

                         u8 *dst, unsigned int *dlen)

{ return 0; }

static int null_decompress(void *ctx, const u8 *src, unsigned int slen,

                           u8 *dst, unsigned int *dlen)

{ return 0; }

static void null_init(void *ctx)

{ }

static void null_update(void *ctx, const u8 *data, unsigned int len)

{ }

static void null_final(void *ctx, u8 *out)

{ }

static int null_setkey(void *ctx, const u8 *key,

                       unsigned int keylen, u32 *flags)

{ return 0; }

static void null_encrypt(void *ctx, u8 *dst, const u8 *src)

{ }

static void null_decrypt(void *ctx, u8 *dst, const u8 *src)

{ }

static struct crypto_alg compress_null = {

        .cra_name               =       "compress_null",

        .cra_flags              =       CRYPTO_ALG_TYPE_COMPRESS,

        .cra_blocksize          =       NULL_BLOCK_SIZE,

        .cra_ctxsize            =       0,

        .cra_module             =       THIS_MODULE,

        .cra_list               =       LIST_HEAD_INIT(compress_null.cra_list),

        .cra_u                  =       { .compress = {

        .coa_compress           =       null_compress,

        .coa_decompress         =       null_decompress } }

};

static struct crypto_alg digest_null = {

        .cra_name               =       "digest_null",

        .cra_flags              =       CRYPTO_ALG_TYPE_DIGEST,

        .cra_blocksize          =       NULL_BLOCK_SIZE,

        .cra_ctxsize            =       0,

        .cra_module             =       THIS_MODULE,

        .cra_list               =       LIST_HEAD_INIT(digest_null.cra_list),

        .cra_u                  =       { .digest = {

        .dia_digestsize         =       NULL_DIGEST_SIZE,

        .dia_init               =       null_init,

        .dia_update             =       null_update,

        .dia_final              =       null_final } }

};

static struct crypto_alg cipher_null = {

        .cra_name               =       "cipher_null",

        .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,

        .cra_blocksize          =       NULL_BLOCK_SIZE,

        .cra_ctxsize            =       0,

        .cra_module             =       THIS_MODULE,

        .cra_list               =       LIST_HEAD_INIT(cipher_null.cra_list),

        .cra_u                  =       { .cipher = {

        .cia_min_keysize        =       NULL_KEY_SIZE,

        .cia_max_keysize        =       NULL_KEY_SIZE,

        .cia_setkey             =       null_setkey,

        .cia_encrypt            =       null_encrypt,

        .cia_decrypt            =       null_decrypt } }

};

static int __init init(void)

{

        int ret = 0;

        ret = crypto_register_alg(&cipher_null);

        if (ret < 0)

                goto out;

        ret = crypto_register_alg(&digest_null);

        if (ret < 0) {

                crypto_unregister_alg(&cipher_null);

                goto out;

        }

        ret = crypto_register_alg(&compress_null);

        if (ret < 0) {

                crypto_unregister_alg(&digest_null);

                crypto_unregister_alg(&cipher_null);

                goto out;

        }

out:

        return ret;

}

static void __exit fini(void)

{

        crypto_unregister_alg(&compress_null);

        crypto_unregister_alg(&digest_null);

        crypto_unregister_alg(&cipher_null);

}

module_init(init);

module_exit(fini);

MODULE_LICENSE("GPL");

MODULE_DESCRIPTION("Null Cryptographic Algorithms");