/*
   * Cryptographic API.
   *
   * Copyright (c) 2013 Chanho Min <chanho.min@lge.com>
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 as published by
   * the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program; if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
   *
   */
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/crypto.h>
  #include <linux/vmalloc.h>
  #include <linux/lz4.h>

  #include <crypto/internal/scompress.h>

  
  struct lz4hc_ctx {
  	void *lz4hc_comp_mem;
  };

  static void *lz4hc_alloc_ctx(struct crypto_scomp *tfm)
  {
  	void *ctx;
  
  	ctx = vmalloc(LZ4HC_MEM_COMPRESS);
  	if (!ctx)
  		return ERR_PTR(-ENOMEM);
  
  	return ctx;
  }

  static int lz4hc_init(struct crypto_tfm *tfm)
  {
  	struct lz4hc_ctx *ctx = crypto_tfm_ctx(tfm);

  	ctx->lz4hc_comp_mem = lz4hc_alloc_ctx(NULL);
  	if (IS_ERR(ctx->lz4hc_comp_mem))

  		return -ENOMEM;
  
  	return 0;
  }

  static void lz4hc_free_ctx(struct crypto_scomp *tfm, void *ctx)
  {
  	vfree(ctx);
  }

  static void lz4hc_exit(struct crypto_tfm *tfm)
  {
  	struct lz4hc_ctx *ctx = crypto_tfm_ctx(tfm);

  	lz4hc_free_ctx(NULL, ctx->lz4hc_comp_mem);

  }

  static int __lz4hc_compress_crypto(const u8 *src, unsigned int slen,
  				   u8 *dst, unsigned int *dlen, void *ctx)

  {

  	int out_len = LZ4_compress_HC(src, dst, slen,
  		*dlen, LZ4HC_DEFAULT_CLEVEL, ctx);

  	if (!out_len)

  		return -EINVAL;

  	*dlen = out_len;

  	return 0;
  }

  static int lz4hc_scompress(struct crypto_scomp *tfm, const u8 *src,
  			   unsigned int slen, u8 *dst, unsigned int *dlen,
  			   void *ctx)
  {
  	return __lz4hc_compress_crypto(src, slen, dst, dlen, ctx);
  }
  
  static int lz4hc_compress_crypto(struct crypto_tfm *tfm, const u8 *src,
  				 unsigned int slen, u8 *dst,
  				 unsigned int *dlen)
  {
  	struct lz4hc_ctx *ctx = crypto_tfm_ctx(tfm);
  
  	return __lz4hc_compress_crypto(src, slen, dst, dlen,
  					ctx->lz4hc_comp_mem);
  }
  
  static int __lz4hc_decompress_crypto(const u8 *src, unsigned int slen,
  				     u8 *dst, unsigned int *dlen, void *ctx)

  {

  	int out_len = LZ4_decompress_safe(src, dst, slen, *dlen);

  	if (out_len < 0)

  		return -EINVAL;

  	*dlen = out_len;
  	return 0;

  }

  static int lz4hc_sdecompress(struct crypto_scomp *tfm, const u8 *src,
  			     unsigned int slen, u8 *dst, unsigned int *dlen,
  			     void *ctx)
  {
  	return __lz4hc_decompress_crypto(src, slen, dst, dlen, NULL);
  }
  
  static int lz4hc_decompress_crypto(struct crypto_tfm *tfm, const u8 *src,
  				   unsigned int slen, u8 *dst,
  				   unsigned int *dlen)
  {
  	return __lz4hc_decompress_crypto(src, slen, dst, dlen, NULL);
  }

  static struct crypto_alg alg_lz4hc = {
  	.cra_name		= "lz4hc",
  	.cra_flags		= CRYPTO_ALG_TYPE_COMPRESS,
  	.cra_ctxsize		= sizeof(struct lz4hc_ctx),
  	.cra_module		= THIS_MODULE,
  	.cra_list		= LIST_HEAD_INIT(alg_lz4hc.cra_list),
  	.cra_init		= lz4hc_init,
  	.cra_exit		= lz4hc_exit,
  	.cra_u			= { .compress = {
  	.coa_compress		= lz4hc_compress_crypto,
  	.coa_decompress		= lz4hc_decompress_crypto } }
  };

  static struct scomp_alg scomp = {
  	.alloc_ctx		= lz4hc_alloc_ctx,
  	.free_ctx		= lz4hc_free_ctx,
  	.compress		= lz4hc_scompress,
  	.decompress		= lz4hc_sdecompress,
  	.base			= {
  		.cra_name	= "lz4hc",
  		.cra_driver_name = "lz4hc-scomp",
  		.cra_module	 = THIS_MODULE,
  	}
  };

  static int __init lz4hc_mod_init(void)
  {

  	int ret;
  
  	ret = crypto_register_alg(&alg_lz4hc);
  	if (ret)
  		return ret;
  
  	ret = crypto_register_scomp(&scomp);
  	if (ret) {
  		crypto_unregister_alg(&alg_lz4hc);
  		return ret;
  	}
  
  	return ret;

  }
  
  static void __exit lz4hc_mod_fini(void)
  {
  	crypto_unregister_alg(&alg_lz4hc);

  	crypto_unregister_scomp(&scomp);

  }
  
  module_init(lz4hc_mod_init);
  module_exit(lz4hc_mod_fini);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("LZ4HC Compression Algorithm");

  MODULE_ALIAS_CRYPTO("lz4hc");