/*
   * ECB: Electronic CodeBook mode
   *
   * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   *
   * 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 option)
   * any later version.
   *
   */
  
  #include <crypto/algapi.h>
  #include <linux/err.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/scatterlist.h>
  #include <linux/slab.h>
  
  struct crypto_ecb_ctx {
  	struct crypto_cipher *child;
  };
  
  static int crypto_ecb_setkey(struct crypto_tfm *parent, const u8 *key,
  			     unsigned int keylen)
  {
  	struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(parent);
  	struct crypto_cipher *child = ctx->child;
  	int err;
  
  	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
  	crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
  				       CRYPTO_TFM_REQ_MASK);
  	err = crypto_cipher_setkey(child, key, keylen);
  	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
  				     CRYPTO_TFM_RES_MASK);
  	return err;
  }
  
  static int crypto_ecb_crypt(struct blkcipher_desc *desc,
  			    struct blkcipher_walk *walk,
  			    struct crypto_cipher *tfm,
  			    void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
  {
  	int bsize = crypto_cipher_blocksize(tfm);
  	unsigned int nbytes;
  	int err;
  
  	err = blkcipher_walk_virt(desc, walk);
  
  	while ((nbytes = walk->nbytes)) {
  		u8 *wsrc = walk->src.virt.addr;
  		u8 *wdst = walk->dst.virt.addr;
  
  		do {
  			fn(crypto_cipher_tfm(tfm), wdst, wsrc);

  			wsrc += bsize;
  			wdst += bsize;
  		} while ((nbytes -= bsize) >= bsize);
  
  		err = blkcipher_walk_done(desc, walk, nbytes);
  	}
  
  	return err;
  }
  
  static int crypto_ecb_encrypt(struct blkcipher_desc *desc,
  			      struct scatterlist *dst, struct scatterlist *src,
  			      unsigned int nbytes)
  {
  	struct blkcipher_walk walk;
  	struct crypto_blkcipher *tfm = desc->tfm;
  	struct crypto_ecb_ctx *ctx = crypto_blkcipher_ctx(tfm);
  	struct crypto_cipher *child = ctx->child;
  
  	blkcipher_walk_init(&walk, dst, src, nbytes);
  	return crypto_ecb_crypt(desc, &walk, child,
  				crypto_cipher_alg(child)->cia_encrypt);
  }
  
  static int crypto_ecb_decrypt(struct blkcipher_desc *desc,
  			      struct scatterlist *dst, struct scatterlist *src,
  			      unsigned int nbytes)
  {
  	struct blkcipher_walk walk;
  	struct crypto_blkcipher *tfm = desc->tfm;
  	struct crypto_ecb_ctx *ctx = crypto_blkcipher_ctx(tfm);
  	struct crypto_cipher *child = ctx->child;
  
  	blkcipher_walk_init(&walk, dst, src, nbytes);
  	return crypto_ecb_crypt(desc, &walk, child,
  				crypto_cipher_alg(child)->cia_decrypt);
  }
  
  static int crypto_ecb_init_tfm(struct crypto_tfm *tfm)
  {
  	struct crypto_instance *inst = (void *)tfm->__crt_alg;
  	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
  	struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);

  	struct crypto_cipher *cipher;

  	cipher = crypto_spawn_cipher(spawn);
  	if (IS_ERR(cipher))
  		return PTR_ERR(cipher);

  	ctx->child = cipher;

  	return 0;
  }
  
  static void crypto_ecb_exit_tfm(struct crypto_tfm *tfm)
  {
  	struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);
  	crypto_free_cipher(ctx->child);
  }

  static struct crypto_instance *crypto_ecb_alloc(struct rtattr **tb)

  {
  	struct crypto_instance *inst;
  	struct crypto_alg *alg;

  	int err;
  
  	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
  	if (err)
  		return ERR_PTR(err);

  	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
  				  CRYPTO_ALG_TYPE_MASK);

  	if (IS_ERR(alg))

  		return ERR_CAST(alg);

  
  	inst = crypto_alloc_instance("ecb", alg);
  	if (IS_ERR(inst))
  		goto out_put_alg;
  
  	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
  	inst->alg.cra_priority = alg->cra_priority;
  	inst->alg.cra_blocksize = alg->cra_blocksize;
  	inst->alg.cra_alignmask = alg->cra_alignmask;
  	inst->alg.cra_type = &crypto_blkcipher_type;
  
  	inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  	inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  
  	inst->alg.cra_ctxsize = sizeof(struct crypto_ecb_ctx);
  
  	inst->alg.cra_init = crypto_ecb_init_tfm;
  	inst->alg.cra_exit = crypto_ecb_exit_tfm;
  
  	inst->alg.cra_blkcipher.setkey = crypto_ecb_setkey;
  	inst->alg.cra_blkcipher.encrypt = crypto_ecb_encrypt;
  	inst->alg.cra_blkcipher.decrypt = crypto_ecb_decrypt;
  
  out_put_alg:
  	crypto_mod_put(alg);
  	return inst;
  }
  
  static void crypto_ecb_free(struct crypto_instance *inst)
  {
  	crypto_drop_spawn(crypto_instance_ctx(inst));
  	kfree(inst);
  }
  
  static struct crypto_template crypto_ecb_tmpl = {
  	.name = "ecb",
  	.alloc = crypto_ecb_alloc,
  	.free = crypto_ecb_free,
  	.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);
  }
  
  module_init(crypto_ecb_module_init);
  module_exit(crypto_ecb_module_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("ECB block cipher algorithm");