lc_rng.h

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/*
 * Copyright (C) 2022 - 2025, Stephan Mueller <smueller@chronox.de>
 *
 * License: see LICENSE file in root directory
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
 * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */
 
#ifndef LC_RNG_H
#define LC_RNG_H
 
#include "lc_memory_support.h"
 
#ifdef __cplusplus
extern "C" {
#endif

struct lc_rng {
        int (*generate)(void *state, const uint8_t *addtl_input,
                        size_t addtl_input_len, uint8_t *out, size_t outlen);
        int (*seed)(void *state, const uint8_t *seed, size_t seedlen,
                    const uint8_t *persbuf, size_t perslen);
        void (*zero)(void *state);
        uint64_t algorithm_type;
};
 
struct lc_rng_ctx {
        const struct lc_rng *rng;
        void *rng_state;
};
 
#define LC_RNG_CTX(name, cb)                                                   \
        name->rng = cb;                                                        \
        name->rng_state = (uint8_t *)(name) + sizeof(struct lc_rng_ctx)


extern struct lc_rng_ctx *lc_seeded_rng;

void lc_rng_check(struct lc_rng_ctx **ctx);

void lc_rng_zero(struct lc_rng_ctx *ctx);

void lc_rng_zero_free(struct lc_rng_ctx *ctx);

int lc_rng_generate(struct lc_rng_ctx *ctx, const uint8_t *addtl_input,
                    size_t addtl_input_len, uint8_t *out, size_t outlen);

int lc_rng_seed(struct lc_rng_ctx *ctx, const uint8_t *seed, size_t seedlen,
                const uint8_t *persbuf, size_t perslen);

int lc_rng_set_seeded(struct lc_rng_ctx *new_ctx);

uint64_t lc_rng_algorithm_type(const struct lc_rng *rng);

uint64_t lc_rng_ctx_algorithm_type(const struct lc_rng_ctx *ctx);
 
#ifdef __cplusplus
}
#endif
 
#endif /* LC_RNG_H */