/* $OpenBSD: xform_ipcomp.c,v 1.8 2019/01/09 12:11:38 mpi Exp $ */

/*
 * Copyright (c) 2001 Jean-Jacques Bernard-Gundol (jj@wabbitt.org)
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This file contains a wrapper around the deflate algo compression
 * functions using the zlib library 
 */

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/systm.h>
#include <lib/libz/zutil.h>

#define Z_METHOD        8
#define Z_MEMLEVEL      8
#define ZBUF            10

u_int32_t deflate_global(u_int8_t *, u_int32_t, int, u_int8_t **);

struct deflate_buf {
        u_int8_t *out;
        u_int32_t size;
        int flag;
};

int window_inflate = -1 * MAX_WBITS;
int window_deflate = -12;

/*
 * This function takes a block of data and (de)compress it using the deflate
 * algorithm
 */

u_int32_t
deflate_global(u_int8_t *data, u_int32_t size, int decomp, u_int8_t **out)
{
        z_stream zbuf;
        u_int8_t *output;
        u_int32_t count, result;
        int error, i = 0, j;
        struct deflate_buf buf[ZBUF];

        bzero(&zbuf, sizeof(z_stream));
        for (j = 0; j < ZBUF; j++)
                buf[j].flag = 0;

        zbuf.next_in = data;    /* data that is going to be processed */
        zbuf.zalloc = zcalloc;
        zbuf.zfree = zcfree;
        zbuf.opaque = Z_NULL;
        zbuf.avail_in = size;   /* Total length of data to be processed */

        if (decomp) {
                /*
                 * Choose a buffer with 4x the size of the input buffer
                 * for the size of the output buffer in the case of
                 * decompression. If it's not sufficient, it will need to be
                 * updated while the decompression is going on
                 */
                if (size < 32 * 1024)
                        size *= 4;
        }
        buf[i].out = malloc((u_long)size, M_CRYPTO_DATA, M_NOWAIT);
        if (buf[i].out == NULL)
                goto bad;
        buf[i].size = size;
        buf[i].flag = 1;
        i++;

        zbuf.next_out = buf[0].out;
        zbuf.avail_out = buf[0].size;

        error = decomp ?
            inflateInit2(&zbuf, window_inflate) :
            deflateInit2(&zbuf, Z_DEFAULT_COMPRESSION, Z_METHOD,
            window_deflate, Z_MEMLEVEL, Z_DEFAULT_STRATEGY);

        if (error != Z_OK)
                goto bad;
        for (;;) {
                error = decomp ?
                    inflate(&zbuf, Z_PARTIAL_FLUSH) :
                    deflate(&zbuf, Z_FINISH);
                if (error == Z_STREAM_END)
                        break;
                if (error != Z_OK)
                        goto bad;
                if (zbuf.avail_out == 0 && i < (ZBUF - 1)) {
                        /* we need more output space, allocate size */
                        if (size < 32 * 1024)
                                size *= 2;
                        buf[i].out = malloc((u_long)size, M_CRYPTO_DATA,
                            M_NOWAIT);
                        if (buf[i].out == NULL)
                                goto bad;
                        zbuf.next_out = buf[i].out;
                        buf[i].size = size;
                        buf[i].flag = 1;
                        zbuf.avail_out = buf[i].size;
                        i++;
                } else
                        goto bad;       /* out of buffers */
        }
        result = count = zbuf.total_out;

        *out = malloc((u_long)result, M_CRYPTO_DATA, M_NOWAIT);
        if (*out == NULL)
                goto bad;
        if (decomp)
                inflateEnd(&zbuf);
        else
                deflateEnd(&zbuf);
        output = *out;
        for (j = 0; buf[j].flag != 0; j++) {
                if (count > buf[j].size) {
                        bcopy(buf[j].out, *out, buf[j].size);
                        *out += buf[j].size;
                        free(buf[j].out, M_CRYPTO_DATA, buf[j].size);
                        count -= buf[j].size;
                } else {
                        /* it should be the last buffer */
                        bcopy(buf[j].out, *out, count);
                        *out += count;
                        free(buf[j].out, M_CRYPTO_DATA, buf[j].size);
                        count = 0;
                }
        }
        *out = output;
        return result;

bad:
        *out = NULL;
        for (j = 0; buf[j].flag != 0; j++)
                free(buf[j].out, M_CRYPTO_DATA, buf[j].size);
        if (decomp)
                inflateEnd(&zbuf);
        else
                deflateEnd(&zbuf);
        return 0;
}