krng.c

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/*
 * RNG implementation using standard kernel RNG.
 *
 * Copyright (c) 2008 Herbert Xu <[email protected]>
 *
 * 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
 * any later version.
 *
 */

#include <crypto/internal/rng.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/random.h>

static int krng_get_random(struct crypto_rng *tfm, u8 *rdata, unsigned int dlen)
{
    get_random_bytes(rdata, dlen);
    return 0;
}

static int krng_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
{
    return 0;
}

static struct crypto_alg krng_alg = {
    .cra_name       = "stdrng",
    .cra_driver_name    = "krng",
    .cra_priority       = 200,
    .cra_flags      = CRYPTO_ALG_TYPE_RNG,
    .cra_ctxsize        = 0,
    .cra_type       = &crypto_rng_type,
    .cra_module     = THIS_MODULE,
    .cra_u          = {
        .rng = {
            .rng_make_random    = krng_get_random,
            .rng_reset      = krng_reset,
            .seedsize       = 0,
        }
    }
};


/* Module initalization */
static int __init krng_mod_init(void)
{
    return crypto_register_alg(&krng_alg);
}

static void __exit krng_mod_fini(void)
{
    crypto_unregister_alg(&krng_alg);
    return;
}

module_init(krng_mod_init);
module_exit(krng_mod_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Kernel Random Number Generator");
MODULE_ALIAS("stdrng");