1/*
  2 * Cryptographic API.
  3 *
  4 * Copyright (c) 2013 Chanho Min <chanho.min@lge.com>
  5 *
  6 * This program is free software; you can redistribute it and/or modify it
  7 * under the terms of the GNU General Public License version 2 as published by
  8 * the Free Software Foundation.
  9 *
 10 * This program is distributed in the hope that it will be useful, but WITHOUT
 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 13 * more details.
 14 *
 15 * You should have received a copy of the GNU General Public License along with
 16 * this program; if not, write to the Free Software Foundation, Inc., 51
 17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 18 *
 19 */
 20#include <linux/init.h>
 21#include <linux/module.h>
 22#include <linux/crypto.h>
 23#include <linux/vmalloc.h>
 24#include <linux/lz4.h>
 25
 26struct lz4hc_ctx {
 27	void *lz4hc_comp_mem;
 28};
 29
 30static int lz4hc_init(struct crypto_tfm *tfm)
 31{
 32	struct lz4hc_ctx *ctx = crypto_tfm_ctx(tfm);
 33
 34	ctx->lz4hc_comp_mem = vmalloc(LZ4HC_MEM_COMPRESS);
 35	if (!ctx->lz4hc_comp_mem)
 36		return -ENOMEM;
 37
 38	return 0;
 39}
 40
 41static void lz4hc_exit(struct crypto_tfm *tfm)
 42{
 43	struct lz4hc_ctx *ctx = crypto_tfm_ctx(tfm);
 44
 45	vfree(ctx->lz4hc_comp_mem);
 46}
 47
 48static int lz4hc_compress_crypto(struct crypto_tfm *tfm, const u8 *src,
 49			    unsigned int slen, u8 *dst, unsigned int *dlen)
 50{
 51	struct lz4hc_ctx *ctx = crypto_tfm_ctx(tfm);
 52	size_t tmp_len = *dlen;
 53	int err;
 54
 55	err = lz4hc_compress(src, slen, dst, &tmp_len, ctx->lz4hc_comp_mem);
 56
 57	if (err < 0)
 58		return -EINVAL;
 59
 60	*dlen = tmp_len;
 61	return 0;
 62}
 63
 64static int lz4hc_decompress_crypto(struct crypto_tfm *tfm, const u8 *src,
 65			      unsigned int slen, u8 *dst, unsigned int *dlen)
 66{
 67	int err;
 68	size_t tmp_len = *dlen;
 69	size_t __slen = slen;
 70
 71	err = lz4_decompress(src, &__slen, dst, tmp_len);
 72	if (err < 0)
 73		return -EINVAL;
 74
 75	*dlen = tmp_len;
 76	return err;
 77}
 78
 79static struct crypto_alg alg_lz4hc = {
 80	.cra_name		= "lz4hc",
 81	.cra_flags		= CRYPTO_ALG_TYPE_COMPRESS,
 82	.cra_ctxsize		= sizeof(struct lz4hc_ctx),
 83	.cra_module		= THIS_MODULE,
 84	.cra_list		= LIST_HEAD_INIT(alg_lz4hc.cra_list),
 85	.cra_init		= lz4hc_init,
 86	.cra_exit		= lz4hc_exit,
 87	.cra_u			= { .compress = {
 88	.coa_compress		= lz4hc_compress_crypto,
 89	.coa_decompress		= lz4hc_decompress_crypto } }
 90};
 91
 92static int __init lz4hc_mod_init(void)
 93{
 94	return crypto_register_alg(&alg_lz4hc);
 95}
 96
 97static void __exit lz4hc_mod_fini(void)
 98{
 99	crypto_unregister_alg(&alg_lz4hc);
100}
101
102module_init(lz4hc_mod_init);
103module_exit(lz4hc_mod_fini);
104
105MODULE_LICENSE("GPL");
106MODULE_DESCRIPTION("LZ4HC Compression Algorithm");