LXR linux-old/crypto/crypto

   1/* 
   2 * Cryptographic API.
   3 *
   4 * Null algorithms, aka Much Ado About Nothing.
   5 *
   6 * These are needed for IPsec, and may be useful in general for
   7 * testing & debugging.
   8 * 
   9 * The null cipher is compliant with RFC2410.
  10 *
  11 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
  12 *
  13 * This program is free software; you can redistribute it and/or modify
  14 * it under the terms of the GNU General Public License as published by
  15 * the Free Software Foundation; either version 2 of the License, or
  16 * (at your option) any later version.
  17 *
  18 */
  19#include <linux/init.h>
  20#include <linux/module.h>
  21#include <linux/mm.h>
  22#include <asm/scatterlist.h>
  23#include <linux/crypto.h>
  24
  25#define NULL_KEY_SIZE           0
  26#define NULL_BLOCK_SIZE         1
  27#define NULL_DIGEST_SIZE        0
  28
  29static int null_compress(void *ctx, const u8 *src, unsigned int slen,
  30                         u8 *dst, unsigned int *dlen)
  31{ return 0; }
  32
  33static int null_decompress(void *ctx, const u8 *src, unsigned int slen,
  34                           u8 *dst, unsigned int *dlen)
  35{ return 0; }
  36
  37static void null_init(void *ctx)
  38{ }
  39
  40static void null_update(void *ctx, const u8 *data, unsigned int len)
  41{ }
  42
  43static void null_final(void *ctx, u8 *out)
  44{ }
  45
  46static int null_setkey(void *ctx, const u8 *key,
  47                       unsigned int keylen, u32 *flags)
  48{ return 0; }
  49
  50static void null_encrypt(void *ctx, u8 *dst, const u8 *src)
  51{ }
  52
  53static void null_decrypt(void *ctx, u8 *dst, const u8 *src)
  54{ }
  55
  56static struct crypto_alg compress_null = {
  57        .cra_name               =       "compress_null",
  58        .cra_flags              =       CRYPTO_ALG_TYPE_COMPRESS,
  59        .cra_blocksize          =       NULL_BLOCK_SIZE,
  60        .cra_ctxsize            =       0,
  61        .cra_module             =       THIS_MODULE,
  62        .cra_list               =       LIST_HEAD_INIT(compress_null.cra_list),
  63        .cra_u                  =       { .compress = {
  64        .coa_compress           =       null_compress,
  65        .coa_decompress         =       null_decompress } }
  66};
  67
  68static struct crypto_alg digest_null = {
  69        .cra_name               =       "digest_null",
  70        .cra_flags              =       CRYPTO_ALG_TYPE_DIGEST,
  71        .cra_blocksize          =       NULL_BLOCK_SIZE,
  72        .cra_ctxsize            =       0,
  73        .cra_module             =       THIS_MODULE,
  74        .cra_list               =       LIST_HEAD_INIT(digest_null.cra_list),   
  75        .cra_u                  =       { .digest = {
  76        .dia_digestsize         =       NULL_DIGEST_SIZE,
  77        .dia_init               =       null_init,
  78        .dia_update             =       null_update,
  79        .dia_final              =       null_final } }
  80};
  81
  82static struct crypto_alg cipher_null = {
  83        .cra_name               =       "cipher_null",
  84        .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
  85        .cra_blocksize          =       NULL_BLOCK_SIZE,
  86        .cra_ctxsize            =       0,
  87        .cra_module             =       THIS_MODULE,
  88        .cra_list               =       LIST_HEAD_INIT(cipher_null.cra_list),
  89        .cra_u                  =       { .cipher = {
  90        .cia_min_keysize        =       NULL_KEY_SIZE,
  91        .cia_max_keysize        =       NULL_KEY_SIZE,
  92        .cia_setkey             =       null_setkey,
  93        .cia_encrypt            =       null_encrypt,
  94        .cia_decrypt            =       null_decrypt } }
  95};
  96
  97static int __init init(void)
  98{
  99        int ret = 0;
 100        
 101        ret = crypto_register_alg(&cipher_null);
 102        if (ret < 0)
 103                goto out;
 104
 105        ret = crypto_register_alg(&digest_null);
 106        if (ret < 0) {
 107                crypto_unregister_alg(&cipher_null);
 108                goto out;
 109        }
 110
 111        ret = crypto_register_alg(&compress_null);
 112        if (ret < 0) {
 113                crypto_unregister_alg(&digest_null);
 114                crypto_unregister_alg(&cipher_null);
 115                goto out;
 116        }
 117
 118out:    
 119        return ret;
 120}
 121
 122static void __exit fini(void)
 123{
 124        crypto_unregister_alg(&compress_null);
 125        crypto_unregister_alg(&digest_null);
 126        crypto_unregister_alg(&cipher_null);
 127}
 128
 129module_init(init);
 130module_exit(fini);
 131
 132MODULE_LICENSE("GPL");
 133MODULE_DESCRIPTION("Null Cryptographic Algorithms");
 134