// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * ECB: Electronic CodeBook mode
   *
   * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>

   */
  
  #include <crypto/algapi.h>

  #include <crypto/internal/skcipher.h>

  #include <linux/err.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/module.h>

  static int crypto_ecb_crypt(struct skcipher_request *req,
  			    struct crypto_cipher *cipher,

  			    void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
  {

  	const unsigned int bsize = crypto_cipher_blocksize(cipher);
  	struct skcipher_walk walk;

  	unsigned int nbytes;
  	int err;

  	err = skcipher_walk_virt(&walk, req, false);

  	while ((nbytes = walk.nbytes) != 0) {
  		const u8 *src = walk.src.virt.addr;
  		u8 *dst = walk.dst.virt.addr;

  
  		do {

  			fn(crypto_cipher_tfm(cipher), dst, src);

  			src += bsize;
  			dst += bsize;

  		} while ((nbytes -= bsize) >= bsize);

  		err = skcipher_walk_done(&walk, nbytes);

  	}
  
  	return err;
  }

  static int crypto_ecb_encrypt(struct skcipher_request *req)

  {

  	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  	struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);

  	return crypto_ecb_crypt(req, cipher,
  				crypto_cipher_alg(cipher)->cia_encrypt);

  }

  static int crypto_ecb_decrypt(struct skcipher_request *req)

  {

  	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  	struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);

  	return crypto_ecb_crypt(req, cipher,
  				crypto_cipher_alg(cipher)->cia_decrypt);

  }

  static int crypto_ecb_create(struct crypto_template *tmpl, struct rtattr **tb)

  {

  	struct skcipher_instance *inst;

  	int err;

  	inst = skcipher_alloc_instance_simple(tmpl, tb);

  	if (IS_ERR(inst))

  		return PTR_ERR(inst);

  	inst->alg.ivsize = 0; /* ECB mode doesn't take an IV */

  	inst->alg.encrypt = crypto_ecb_encrypt;
  	inst->alg.decrypt = crypto_ecb_decrypt;

  	err = skcipher_register_instance(tmpl, inst);
  	if (err)
  		inst->free(inst);

  	return err;

  }
  
  static struct crypto_template crypto_ecb_tmpl = {
  	.name = "ecb",

  	.create = crypto_ecb_create,

  	.module = THIS_MODULE,
  };
  
  static int __init crypto_ecb_module_init(void)
  {
  	return crypto_register_template(&crypto_ecb_tmpl);
  }
  
  static void __exit crypto_ecb_module_exit(void)
  {
  	crypto_unregister_template(&crypto_ecb_tmpl);
  }

  subsys_initcall(crypto_ecb_module_init);

  module_exit(crypto_ecb_module_exit);
  
  MODULE_LICENSE("GPL");

  MODULE_DESCRIPTION("ECB block cipher mode of operation");

  MODULE_ALIAS_CRYPTO("ecb");