[linux-block.git] / crypto / deflate.c

/* 
 * Cryptographic API.
 *
 * Deflate algorithm (RFC 1951), implemented here primarily for use
 * by IPCOMP (RFC 3173 & RFC 2394).
 *
 * Copyright (c) 2003 James Morris <jmorris@intercode.com.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.
 *
 * FIXME: deflate transforms will require up to a total of about 436k of kernel
 * memory on i386 (390k for compression, the rest for decompression), as the
 * current zlib kernel code uses a worst case pre-allocation system by default.
 * This needs to be fixed so that the amount of memory required is properly
 * related to the  winbits and memlevel parameters.
 *
 * The default winbits of 11 should suit most packets, and it may be something
 * to configure on a per-tfm basis in the future.
 *
 * Currently, compression history is not maintained between tfm calls, as
 * it is not needed for IPCOMP and keeps the code simpler.  It can be
 * implemented if someone wants it.
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/crypto.h>
#include <linux/zlib.h>
#include <linux/vmalloc.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/net.h>
#include <linux/slab.h>

#define DEFLATE_DEF_LEVEL		Z_DEFAULT_COMPRESSION
#define DEFLATE_DEF_WINBITS		11
#define DEFLATE_DEF_MEMLEVEL		MAX_MEM_LEVEL

struct deflate_ctx {
	struct z_stream_s comp_stream;
	struct z_stream_s decomp_stream;
};

static int deflate_comp_init(struct deflate_ctx *ctx)
{
	int ret = 0;
	struct z_stream_s *stream = &ctx->comp_stream;

	stream->workspace = vmalloc(zlib_deflate_workspacesize());
	if (!stream->workspace ) {
		ret = -ENOMEM;
		goto out;
	}
	memset(stream->workspace, 0, zlib_deflate_workspacesize());
	ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED,
	                        -DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL,
	                        Z_DEFAULT_STRATEGY);
	if (ret != Z_OK) {
		ret = -EINVAL;
		goto out_free;
	}
out:	
	return ret;
out_free:
	vfree(stream->workspace);
	goto out;
}

static int deflate_decomp_init(struct deflate_ctx *ctx)
{
	int ret = 0;
	struct z_stream_s *stream = &ctx->decomp_stream;

	stream->workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
	if (!stream->workspace ) {
		ret = -ENOMEM;
		goto out;
	}
	memset(stream->workspace, 0, zlib_inflate_workspacesize());
	ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS);
	if (ret != Z_OK) {
		ret = -EINVAL;
		goto out_free;
	}
out:
	return ret;
out_free:
	kfree(stream->workspace);
	goto out;
}

static void deflate_comp_exit(struct deflate_ctx *ctx)
{
	zlib_deflateEnd(&ctx->comp_stream);
	vfree(ctx->comp_stream.workspace);
}

static void deflate_decomp_exit(struct deflate_ctx *ctx)
{
	zlib_inflateEnd(&ctx->decomp_stream);
	kfree(ctx->decomp_stream.workspace);
}

static int deflate_init(void *ctx)
{
	int ret;
	
	ret = deflate_comp_init(ctx);
	if (ret)
		goto out;
	ret = deflate_decomp_init(ctx);
	if (ret)
		deflate_comp_exit(ctx);
out:
	return ret;
}

static void deflate_exit(void *ctx)
{
	deflate_comp_exit(ctx);
	deflate_decomp_exit(ctx);
}

static int deflate_compress(void *ctx, const u8 *src, unsigned int slen,
	                    u8 *dst, unsigned int *dlen)
{
	int ret = 0;
	struct deflate_ctx *dctx = ctx;
	struct z_stream_s *stream = &dctx->comp_stream;

	ret = zlib_deflateReset(stream);
	if (ret != Z_OK) {
		ret = -EINVAL;
		goto out;
	}

	stream->next_in = (u8 *)src;
	stream->avail_in = slen;
	stream->next_out = (u8 *)dst;
	stream->avail_out = *dlen;

	ret = zlib_deflate(stream, Z_FINISH);
	if (ret != Z_STREAM_END) {
		ret = -EINVAL;
		goto out;
	}
	ret = 0;
	*dlen = stream->total_out;
out:
	return ret;
}
 
static int deflate_decompress(void *ctx, const u8 *src, unsigned int slen,
                              u8 *dst, unsigned int *dlen)
{
	
	int ret = 0;
	struct deflate_ctx *dctx = ctx;
	struct z_stream_s *stream = &dctx->decomp_stream;

	ret = zlib_inflateReset(stream);
	if (ret != Z_OK) {
		ret = -EINVAL;
		goto out;
	}

	stream->next_in = (u8 *)src;
	stream->avail_in = slen;
	stream->next_out = (u8 *)dst;
	stream->avail_out = *dlen;

	ret = zlib_inflate(stream, Z_SYNC_FLUSH);
	/*
	 * Work around a bug in zlib, which sometimes wants to taste an extra
	 * byte when being used in the (undocumented) raw deflate mode.
	 * (From USAGI).
	 */
	if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
		u8 zerostuff = 0;
		stream->next_in = &zerostuff;
		stream->avail_in = 1; 
		ret = zlib_inflate(stream, Z_FINISH);
	}
	if (ret != Z_STREAM_END) {
		ret = -EINVAL;
		goto out;
	}
	ret = 0;
	*dlen = stream->total_out;
out:
	return ret;
}

static struct crypto_alg alg = {
	.cra_name		= "deflate",
	.cra_flags		= CRYPTO_ALG_TYPE_COMPRESS,
	.cra_ctxsize		= sizeof(struct deflate_ctx),
	.cra_module		= THIS_MODULE,
	.cra_list		= LIST_HEAD_INIT(alg.cra_list),
	.cra_u			= { .compress = {
	.coa_init		= deflate_init,
	.coa_exit		= deflate_exit,
	.coa_compress 		= deflate_compress,
	.coa_decompress  	= deflate_decompress } }
};

static int __init init(void)
{
	return crypto_register_alg(&alg);
}

static void __exit fini(void)
{
	crypto_unregister_alg(&alg);
}

module_init(init);
module_exit(fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Cryptographic API.
	3	*
	4	* Deflate algorithm (RFC 1951), implemented here primarily for use
	5	* by IPCOMP (RFC 3173 & RFC 2394).
	6	*
	7	* Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
	8	*
	9	* This program is free software; you can redistribute it and/or modify it
	10	* under the terms of the GNU General Public License as published by the Free
	11	* Software Foundation; either version 2 of the License, or (at your option)
	12	* any later version.
	13	*
	14	* FIXME: deflate transforms will require up to a total of about 436k of kernel
	15	* memory on i386 (390k for compression, the rest for decompression), as the
	16	* current zlib kernel code uses a worst case pre-allocation system by default.
	17	* This needs to be fixed so that the amount of memory required is properly
	18	* related to the winbits and memlevel parameters.
	19	*
	20	* The default winbits of 11 should suit most packets, and it may be something
	21	* to configure on a per-tfm basis in the future.
	22	*
	23	* Currently, compression history is not maintained between tfm calls, as
	24	* it is not needed for IPCOMP and keeps the code simpler. It can be
	25	* implemented if someone wants it.
	26	*/
	27	#include <linux/init.h>
	28	#include <linux/module.h>
	29	#include <linux/crypto.h>
	30	#include <linux/zlib.h>
	31	#include <linux/vmalloc.h>
	32	#include <linux/interrupt.h>
	33	#include <linux/mm.h>
	34	#include <linux/net.h>
	35	#include <linux/slab.h>
	36
	37	#define DEFLATE_DEF_LEVEL Z_DEFAULT_COMPRESSION
	38	#define DEFLATE_DEF_WINBITS 11
	39	#define DEFLATE_DEF_MEMLEVEL MAX_MEM_LEVEL
	40
	41	struct deflate_ctx {
	42	struct z_stream_s comp_stream;
	43	struct z_stream_s decomp_stream;
	44	};
	45
	46	static int deflate_comp_init(struct deflate_ctx *ctx)
	47	{
	48	int ret = 0;
	49	struct z_stream_s *stream = &ctx->comp_stream;
	50
	51	stream->workspace = vmalloc(zlib_deflate_workspacesize());
	52	if (!stream->workspace ) {
	53	ret = -ENOMEM;
	54	goto out;
	55	}
	56	memset(stream->workspace, 0, zlib_deflate_workspacesize());
	57	ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED,
	58	-DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL,
	59	Z_DEFAULT_STRATEGY);
	60	if (ret != Z_OK) {
	61	ret = -EINVAL;
	62	goto out_free;
	63	}
	64	out:
65	return ret;
66	out_free:
67	vfree(stream->workspace);
68	goto out;
69	}
70
71	static int deflate_decomp_init(struct deflate_ctx *ctx)
72	{
73	int ret = 0;
74	struct z_stream_s *stream = &ctx->decomp_stream;
75
76	stream->workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
77	if (!stream->workspace ) {
78	ret = -ENOMEM;
79	goto out;
80	}
81	memset(stream->workspace, 0, zlib_inflate_workspacesize());
82	ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS);
83	if (ret != Z_OK) {
84	ret = -EINVAL;
85	goto out_free;
86	}
87	out:
88	return ret;
89	out_free:
90	kfree(stream->workspace);
91	goto out;
92	}
93
94	static void deflate_comp_exit(struct deflate_ctx *ctx)
95	{
9ffb7146	96	zlib_deflateEnd(&ctx->comp_stream);
1da177e4 LT	97	vfree(ctx->comp_stream.workspace);
	98	}
	99
	100	static void deflate_decomp_exit(struct deflate_ctx *ctx)
	101	{
9ffb7146	102	zlib_inflateEnd(&ctx->decomp_stream);
1da177e4 LT	103	kfree(ctx->decomp_stream.workspace);
	104	}
	105
	106	static int deflate_init(void *ctx)
	107	{
	108	int ret;
	109
	110	ret = deflate_comp_init(ctx);
	111	if (ret)
	112	goto out;
	113	ret = deflate_decomp_init(ctx);
	114	if (ret)
	115	deflate_comp_exit(ctx);
	116	out:
	117	return ret;
	118	}
	119
	120	static void deflate_exit(void *ctx)
	121	{
	122	deflate_comp_exit(ctx);
	123	deflate_decomp_exit(ctx);
	124	}
	125
	126	static int deflate_compress(void ctx, const u8 src, unsigned int slen,
	127	u8 dst, unsigned int dlen)
	128	{
	129	int ret = 0;
	130	struct deflate_ctx *dctx = ctx;
	131	struct z_stream_s *stream = &dctx->comp_stream;
	132
	133	ret = zlib_deflateReset(stream);
	134	if (ret != Z_OK) {
	135	ret = -EINVAL;
	136	goto out;
	137	}
	138
	139	stream->next_in = (u8 *)src;
	140	stream->avail_in = slen;
	141	stream->next_out = (u8 *)dst;
	142	stream->avail_out = *dlen;
	143
	144	ret = zlib_deflate(stream, Z_FINISH);
	145	if (ret != Z_STREAM_END) {
	146	ret = -EINVAL;
	147	goto out;
	148	}
	149	ret = 0;
	150	*dlen = stream->total_out;
	151	out:
	152	return ret;
	153	}
	154
	155	static int deflate_decompress(void ctx, const u8 src, unsigned int slen,
	156	u8 dst, unsigned int dlen)
	157	{
	158
	159	int ret = 0;
	160	struct deflate_ctx *dctx = ctx;
	161	struct z_stream_s *stream = &dctx->decomp_stream;
	162
	163	ret = zlib_inflateReset(stream);
	164	if (ret != Z_OK) {
	165	ret = -EINVAL;
	166	goto out;
167	}
168
169	stream->next_in = (u8 *)src;
170	stream->avail_in = slen;
171	stream->next_out = (u8 *)dst;
172	stream->avail_out = *dlen;
173
174	ret = zlib_inflate(stream, Z_SYNC_FLUSH);
175	/*
176	* Work around a bug in zlib, which sometimes wants to taste an extra
177	* byte when being used in the (undocumented) raw deflate mode.
178	* (From USAGI).
179	*/
180	if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
181	u8 zerostuff = 0;
182	stream->next_in = &zerostuff;
183	stream->avail_in = 1;
184	ret = zlib_inflate(stream, Z_FINISH);
185	}
186	if (ret != Z_STREAM_END) {
187	ret = -EINVAL;
188	goto out;
189	}
190	ret = 0;
191	*dlen = stream->total_out;
192	out:
193	return ret;
194	}
195
196	static struct crypto_alg alg = {
197	.cra_name = "deflate",
198	.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
199	.cra_ctxsize = sizeof(struct deflate_ctx),
200	.cra_module = THIS_MODULE,
201	.cra_list = LIST_HEAD_INIT(alg.cra_list),
202	.cra_u = { .compress = {
203	.coa_init = deflate_init,
204	.coa_exit = deflate_exit,
205	.coa_compress = deflate_compress,
206	.coa_decompress = deflate_decompress } }
207	};
208
209	static int __init init(void)
210	{
211	return crypto_register_alg(&alg);
212	}
213
214	static void __exit fini(void)
215	{
216	crypto_unregister_alg(&alg);
217	}
218
219	module_init(init);
220	module_exit(fini);
221
222	MODULE_LICENSE("GPL");
223	MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
224	MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
225