deflate.c 7.86 KB
Newer Older
1
/*
Linus Torvalds's avatar
Linus Torvalds committed
2 3 4 5 6 7
 * 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>
8
 *
Linus Torvalds's avatar
Linus Torvalds committed
9 10
 * 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
11
 * Software Foundation; either version 2 of the License, or (at your option)
Linus Torvalds's avatar
Linus Torvalds committed
12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34
 * 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>
35
#include <crypto/internal/scompress.h>
Linus Torvalds's avatar
Linus Torvalds committed
36 37 38 39 40 41 42 43 44 45

#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;
};

46
static int deflate_comp_init(struct deflate_ctx *ctx, int format)
Linus Torvalds's avatar
Linus Torvalds committed
47 48 49 50
{
	int ret = 0;
	struct z_stream_s *stream = &ctx->comp_stream;

51
	stream->workspace = vzalloc(zlib_deflate_workspacesize(
52
				    MAX_WBITS, MAX_MEM_LEVEL));
53
	if (!stream->workspace) {
Linus Torvalds's avatar
Linus Torvalds committed
54 55 56
		ret = -ENOMEM;
		goto out;
	}
57 58 59 60 61 62 63
	if (format)
		ret = zlib_deflateInit(stream, 3);
	else
		ret = zlib_deflateInit2(stream, DEFLATE_DEF_LEVEL, Z_DEFLATED,
					-DEFLATE_DEF_WINBITS,
					DEFLATE_DEF_MEMLEVEL,
					Z_DEFAULT_STRATEGY);
Linus Torvalds's avatar
Linus Torvalds committed
64 65 66 67
	if (ret != Z_OK) {
		ret = -EINVAL;
		goto out_free;
	}
68
out:
Linus Torvalds's avatar
Linus Torvalds committed
69 70 71 72 73 74
	return ret;
out_free:
	vfree(stream->workspace);
	goto out;
}

75
static int deflate_decomp_init(struct deflate_ctx *ctx, int format)
Linus Torvalds's avatar
Linus Torvalds committed
76 77 78 79
{
	int ret = 0;
	struct z_stream_s *stream = &ctx->decomp_stream;

80
	stream->workspace = vzalloc(zlib_inflate_workspacesize());
81
	if (!stream->workspace) {
Linus Torvalds's avatar
Linus Torvalds committed
82 83 84
		ret = -ENOMEM;
		goto out;
	}
85 86 87 88
	if (format)
		ret = zlib_inflateInit(stream);
	else
		ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS);
Linus Torvalds's avatar
Linus Torvalds committed
89 90 91 92 93 94 95
	if (ret != Z_OK) {
		ret = -EINVAL;
		goto out_free;
	}
out:
	return ret;
out_free:
96
	vfree(stream->workspace);
Linus Torvalds's avatar
Linus Torvalds committed
97 98 99 100 101
	goto out;
}

static void deflate_comp_exit(struct deflate_ctx *ctx)
{
102
	zlib_deflateEnd(&ctx->comp_stream);
Linus Torvalds's avatar
Linus Torvalds committed
103 104 105 106 107
	vfree(ctx->comp_stream.workspace);
}

static void deflate_decomp_exit(struct deflate_ctx *ctx)
{
108
	zlib_inflateEnd(&ctx->decomp_stream);
109
	vfree(ctx->decomp_stream.workspace);
Linus Torvalds's avatar
Linus Torvalds committed
110 111
}

112
static int __deflate_init(void *ctx, int format)
Linus Torvalds's avatar
Linus Torvalds committed
113 114
{
	int ret;
115

116
	ret = deflate_comp_init(ctx, format);
Linus Torvalds's avatar
Linus Torvalds committed
117 118
	if (ret)
		goto out;
119
	ret = deflate_decomp_init(ctx, format);
Linus Torvalds's avatar
Linus Torvalds committed
120 121 122 123 124 125
	if (ret)
		deflate_comp_exit(ctx);
out:
	return ret;
}

126
static void *gen_deflate_alloc_ctx(struct crypto_scomp *tfm, int format)
127 128 129 130 131 132 133 134
{
	struct deflate_ctx *ctx;
	int ret;

	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
	if (!ctx)
		return ERR_PTR(-ENOMEM);

135
	ret = __deflate_init(ctx, format);
136 137 138 139 140 141 142 143
	if (ret) {
		kfree(ctx);
		return ERR_PTR(ret);
	}

	return ctx;
}

144 145 146 147 148 149 150 151 152 153
static void *deflate_alloc_ctx(struct crypto_scomp *tfm)
{
	return gen_deflate_alloc_ctx(tfm, 0);
}

static void *zlib_deflate_alloc_ctx(struct crypto_scomp *tfm)
{
	return gen_deflate_alloc_ctx(tfm, 1);
}

154
static int deflate_init(struct crypto_tfm *tfm)
Linus Torvalds's avatar
Linus Torvalds committed
155
{
156 157
	struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);

158
	return __deflate_init(ctx, 0);
159 160 161 162
}

static void __deflate_exit(void *ctx)
{
Linus Torvalds's avatar
Linus Torvalds committed
163 164 165 166
	deflate_comp_exit(ctx);
	deflate_decomp_exit(ctx);
}

167 168 169 170 171 172 173 174 175 176 177 178 179 180 181
static void deflate_free_ctx(struct crypto_scomp *tfm, void *ctx)
{
	__deflate_exit(ctx);
	kzfree(ctx);
}

static void deflate_exit(struct crypto_tfm *tfm)
{
	struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);

	__deflate_exit(ctx);
}

static int __deflate_compress(const u8 *src, unsigned int slen,
			      u8 *dst, unsigned int *dlen, void *ctx)
Linus Torvalds's avatar
Linus Torvalds committed
182 183
{
	int ret = 0;
184
	struct deflate_ctx *dctx = ctx;
Linus Torvalds's avatar
Linus Torvalds committed
185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207
	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;
}
208

209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225
static int deflate_compress(struct crypto_tfm *tfm, const u8 *src,
			    unsigned int slen, u8 *dst, unsigned int *dlen)
{
	struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);

	return __deflate_compress(src, slen, dst, dlen, dctx);
}

static int deflate_scompress(struct crypto_scomp *tfm, const u8 *src,
			     unsigned int slen, u8 *dst, unsigned int *dlen,
			     void *ctx)
{
	return __deflate_compress(src, slen, dst, dlen, ctx);
}

static int __deflate_decompress(const u8 *src, unsigned int slen,
				u8 *dst, unsigned int *dlen, void *ctx)
Linus Torvalds's avatar
Linus Torvalds committed
226
{
227

Linus Torvalds's avatar
Linus Torvalds committed
228
	int ret = 0;
229
	struct deflate_ctx *dctx = ctx;
Linus Torvalds's avatar
Linus Torvalds committed
230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251
	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;
252
		stream->avail_in = 1;
Linus Torvalds's avatar
Linus Torvalds committed
253 254 255 256 257 258 259 260 261 262 263 264
		ret = zlib_inflate(stream, Z_FINISH);
	}
	if (ret != Z_STREAM_END) {
		ret = -EINVAL;
		goto out;
	}
	ret = 0;
	*dlen = stream->total_out;
out:
	return ret;
}

265 266 267 268 269 270 271 272 273 274 275 276 277 278 279
static int deflate_decompress(struct crypto_tfm *tfm, const u8 *src,
			      unsigned int slen, u8 *dst, unsigned int *dlen)
{
	struct deflate_ctx *dctx = crypto_tfm_ctx(tfm);

	return __deflate_decompress(src, slen, dst, dlen, dctx);
}

static int deflate_sdecompress(struct crypto_scomp *tfm, const u8 *src,
			       unsigned int slen, u8 *dst, unsigned int *dlen,
			       void *ctx)
{
	return __deflate_decompress(src, slen, dst, dlen, ctx);
}

Linus Torvalds's avatar
Linus Torvalds committed
280 281 282 283 284
static struct crypto_alg alg = {
	.cra_name		= "deflate",
	.cra_flags		= CRYPTO_ALG_TYPE_COMPRESS,
	.cra_ctxsize		= sizeof(struct deflate_ctx),
	.cra_module		= THIS_MODULE,
285 286
	.cra_init		= deflate_init,
	.cra_exit		= deflate_exit,
Linus Torvalds's avatar
Linus Torvalds committed
287 288 289 290 291
	.cra_u			= { .compress = {
	.coa_compress 		= deflate_compress,
	.coa_decompress  	= deflate_decompress } }
};

292
static struct scomp_alg scomp[] = { {
293 294 295 296 297 298 299 300 301
	.alloc_ctx		= deflate_alloc_ctx,
	.free_ctx		= deflate_free_ctx,
	.compress		= deflate_scompress,
	.decompress		= deflate_sdecompress,
	.base			= {
		.cra_name	= "deflate",
		.cra_driver_name = "deflate-scomp",
		.cra_module	 = THIS_MODULE,
	}
302 303 304 305 306 307 308 309 310 311 312
}, {
	.alloc_ctx		= zlib_deflate_alloc_ctx,
	.free_ctx		= deflate_free_ctx,
	.compress		= deflate_scompress,
	.decompress		= deflate_sdecompress,
	.base			= {
		.cra_name	= "zlib-deflate",
		.cra_driver_name = "zlib-deflate-scomp",
		.cra_module	 = THIS_MODULE,
	}
} };
313

314
static int __init deflate_mod_init(void)
Linus Torvalds's avatar
Linus Torvalds committed
315
{
316 317 318 319 320 321
	int ret;

	ret = crypto_register_alg(&alg);
	if (ret)
		return ret;

322
	ret = crypto_register_scomps(scomp, ARRAY_SIZE(scomp));
323 324 325 326 327 328
	if (ret) {
		crypto_unregister_alg(&alg);
		return ret;
	}

	return ret;
Linus Torvalds's avatar
Linus Torvalds committed
329 330
}

331
static void __exit deflate_mod_fini(void)
Linus Torvalds's avatar
Linus Torvalds committed
332 333
{
	crypto_unregister_alg(&alg);
334
	crypto_unregister_scomps(scomp, ARRAY_SIZE(scomp));
Linus Torvalds's avatar
Linus Torvalds committed
335 336
}

337 338
module_init(deflate_mod_init);
module_exit(deflate_mod_fini);
Linus Torvalds's avatar
Linus Torvalds committed
339 340 341 342

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
343
MODULE_ALIAS_CRYPTO("deflate");