linux/crypto/deflate.c

344 lines
7.9 KiB
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 <crypto/internal/scompress.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 format)
{
int ret = 0;
struct z_stream_s *stream = &ctx->comp_stream;
stream->workspace = vzalloc(zlib_deflate_workspacesize(
MAX_WBITS, MAX_MEM_LEVEL));
if (!stream->workspace) {
ret = -ENOMEM;
goto out;
}
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);
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 format)
{
int ret = 0;
struct z_stream_s *stream = &ctx->decomp_stream;
stream->workspace = vzalloc(zlib_inflate_workspacesize());
if (!stream->workspace) {
ret = -ENOMEM;
goto out;
}
if (format)
ret = zlib_inflateInit(stream);
else
ret = zlib_inflateInit2(stream, -DEFLATE_DEF_WINBITS);
if (ret != Z_OK) {
ret = -EINVAL;
goto out_free;
}
out:
return ret;
out_free:
vfree(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);
vfree(ctx->decomp_stream.workspace);
}
static int __deflate_init(void *ctx, int format)
{
int ret;
ret = deflate_comp_init(ctx, format);
if (ret)
goto out;
ret = deflate_decomp_init(ctx, format);
if (ret)
deflate_comp_exit(ctx);
out:
return ret;
}
static void *gen_deflate_alloc_ctx(struct crypto_scomp *tfm, int format)
{
struct deflate_ctx *ctx;
int ret;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return ERR_PTR(-ENOMEM);
ret = __deflate_init(ctx, format);
if (ret) {
kfree(ctx);
return ERR_PTR(ret);
}
return ctx;
}
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);
}
static int deflate_init(struct crypto_tfm *tfm)
{
struct deflate_ctx *ctx = crypto_tfm_ctx(tfm);
return __deflate_init(ctx, 0);
}
static void __deflate_exit(void *ctx)
{
deflate_comp_exit(ctx);
deflate_decomp_exit(ctx);
}
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)
{
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_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)
{
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 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);
}
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_init = deflate_init,
.cra_exit = deflate_exit,
.cra_u = { .compress = {
.coa_compress = deflate_compress,
.coa_decompress = deflate_decompress } }
};
static struct scomp_alg scomp[] = { {
.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,
}
}, {
.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,
}
} };
static int __init deflate_mod_init(void)
{
int ret;
ret = crypto_register_alg(&alg);
if (ret)
return ret;
ret = crypto_register_scomps(scomp, ARRAY_SIZE(scomp));
if (ret) {
crypto_unregister_alg(&alg);
return ret;
}
return ret;
}
static void __exit deflate_mod_fini(void)
{
crypto_unregister_alg(&alg);
crypto_unregister_scomps(scomp, ARRAY_SIZE(scomp));
}
subsys_initcall(deflate_mod_init);
module_exit(deflate_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Deflate Compression Algorithm for IPCOMP");
MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
MODULE_ALIAS_CRYPTO("deflate");