// SPDX-License-Identifier: GPL-2.0

/*
 * SM4 Cipher Algorithm.
 *
 * Copyright (C) 2018 ARM Limited or its affiliates.
 * All rights reserved.
 */

#include <crypto/algapi.h>
#include <crypto/sm4.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <asm/byteorder.h>
#include <linux/unaligned.h>

/**
 * sm4_setkey - Set the SM4 key.
 * @tfm:        The %crypto_tfm that is used in the context.
 * @in_key:     The input key.
 * @key_len:    The size of the key.
 *
 * This function uses sm4_expandkey() to expand the key.
 * &sm4_ctx _must_ be the private data embedded in @tfm which is
 * retrieved with crypto_tfm_ctx().
 *
 * Return: 0 on success; -EINVAL on failure (only happens for bad key lengths)
 */
static int sm4_setkey(struct crypto_tfm *tfm, const u8 *in_key,
                       unsigned int key_len)
{
        struct sm4_ctx *ctx = crypto_tfm_ctx(tfm);

        return sm4_expandkey(ctx, in_key, key_len);
}

/* encrypt a block of text */

static void sm4_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
        const struct sm4_ctx *ctx = crypto_tfm_ctx(tfm);

        sm4_crypt_block(ctx->rkey_enc, out, in);
}

/* decrypt a block of text */

static void sm4_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
        const struct sm4_ctx *ctx = crypto_tfm_ctx(tfm);

        sm4_crypt_block(ctx->rkey_dec, out, in);
}

static struct crypto_alg sm4_alg = {
        .cra_name               =       "sm4",
        .cra_driver_name        =       "sm4-generic",
        .cra_priority           =       100,
        .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
        .cra_blocksize          =       SM4_BLOCK_SIZE,
        .cra_ctxsize            =       sizeof(struct sm4_ctx),
        .cra_module             =       THIS_MODULE,
        .cra_u                  =       {
                .cipher = {
                        .cia_min_keysize        =       SM4_KEY_SIZE,
                        .cia_max_keysize        =       SM4_KEY_SIZE,
                        .cia_setkey             =       sm4_setkey,
                        .cia_encrypt            =       sm4_encrypt,
                        .cia_decrypt            =       sm4_decrypt
                }
        }
};

static int __init sm4_init(void)
{
        return crypto_register_alg(&sm4_alg);
}

static void __exit sm4_fini(void)
{
        crypto_unregister_alg(&sm4_alg);
}

module_init(sm4_init);
module_exit(sm4_fini);

MODULE_DESCRIPTION("SM4 Cipher Algorithm");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_CRYPTO("sm4");
MODULE_ALIAS_CRYPTO("sm4-generic");