linux-imx

/*

 * 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);