/*
* ppp_deflate.c - interface the zlib procedures for Deflate compression
* and decompression (as used by gzip) to the PPP code.
*
* Copyright (c) 1994 The Australian National University.
* All rights reserved.
*
* Permission to use, copy, modify, and distribute this software and its
* documentation is hereby granted, provided that the above copyright
* notice appears in all copies. This software is provided without any
* warranty, express or implied. The Australian National University
* makes no representations about the suitability of this software for
* any purpose.
*
* IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
* PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
* THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
* OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
* OR MODIFICATIONS.
*
* $Id: deflate.c,v 1.3 1999/04/16 11:35:59 paulus Exp $
*/
#include <sys/types.h>
#include <stddef.h>
#include <stdlib.h>
#ifdef PPP_DEFS_IN_NET
#include <net/ppp_defs.h>
#else
#include "ppp_defs.h"
#endif
#include "ppp-comp.h"
#include "zlib.h"
#if DO_DEFLATE
#define DEFLATE_DEBUG 1
/*
* State for a Deflate (de)compressor.
*/
struct deflate_state {
int seqno;
int w_size;
int unit;
int hdrlen;
int mru;
int debug;
z_stream strm;
struct compstat stats;
};
#define DEFLATE_OVHD 2 /* Deflate overhead/packet */
static void *z_alloc __P((void *, u_int items, u_int size));
static void z_free __P((void *, void *ptr, u_int nb));
static void *z_decomp_alloc __P((u_char *options, int opt_len));
static void z_decomp_free __P((void *state));
static int z_decomp_init __P((void *state, u_char *options, int opt_len,
int unit, int hdrlen, int mru, int debug));
static void z_incomp __P((void *state, u_char *dmsg, int len));
static int z_decompress __P((void *state, u_char *cmp, int inlen,
u_char *dmp, int *outlenp));
static void z_decomp_reset __P((void *state));
static void z_comp_stats __P((void *state, struct compstat *stats));
/*
* Procedures exported to if_ppp.c.
*/
struct compressor ppp_deflate = {
CI_DEFLATE, /* compress_proto */
z_decomp_alloc, /* decomp_alloc */
z_decomp_free, /* decomp_free */
z_decomp_init, /* decomp_init */
z_decomp_reset, /* decomp_reset */
z_decompress, /* decompress */
z_incomp, /* incomp */
z_comp_stats, /* decomp_stat */
};
/*
* Space allocation and freeing routines for use by zlib routines.
*/
static void *
z_alloc(notused, items, size)
void *notused;
u_int items, size;
{
return malloc(items * size);
}
static void
z_free(notused, ptr, nbytes)
void *notused;
void *ptr;
u_int nbytes;
{
free(ptr);
}
static void
z_comp_stats(arg, stats)
void *arg;
struct compstat *stats;
{
struct deflate_state *state = (struct deflate_state *) arg;
u_int out;
*stats = state->stats;
stats->ratio = stats->unc_bytes;
out = stats->comp_bytes + stats->unc_bytes;
if (stats->ratio <= 0x7ffffff)
stats->ratio <<= 8;
else
out >>= 8;
if (out != 0)
stats->ratio /= out;
}
/*
* Allocate space for a decompressor.
*/
static void *
z_decomp_alloc(options, opt_len)
u_char *options;
int opt_len;
{
struct deflate_state *state;
int w_size;
if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
|| options[1] != CILEN_DEFLATE
|| DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
|| options[3] != DEFLATE_CHK_SEQUENCE)
return NULL;
w_size = DEFLATE_SIZE(options[2]);
if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
return NULL;
state = (struct deflate_state *) malloc(sizeof(*state));
if (state == NULL)
return NULL;
state->strm.next_out = NULL;
state->strm.zalloc = (alloc_func) z_alloc;
state->strm.zfree = (free_func) z_free;
if (inflateInit2(&state->strm, -w_size) != Z_OK) {
free(state);
return NULL;
}
state->w_size = w_size;
memset(&state->stats, 0, sizeof(state->stats));
return (void *) state;
}
static void
z_decomp_free(arg)
void *arg;
{
struct deflate_state *state = (struct deflate_state *) arg;
inflateEnd(&state->strm);
free(state);
}
static int
z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
void *arg;
u_char *options;
int opt_len, unit, hdrlen, mru, debug;
{
struct deflate_state *state = (struct deflate_state *) arg;
if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
|| options[1] != CILEN_DEFLATE
|| DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
|| DEFLATE_SIZE(options[2]) != state->w_size
|| options[3] != DEFLATE_CHK_SEQUENCE)
return 0;
state->seqno = 0;
state->unit = unit;
state->hdrlen = hdrlen;
state->debug = debug;
state->mru = mru;
inflateReset(&state->strm);
return 1;
}
static void
z_decomp_reset(arg)
void *arg;
{
struct deflate_state *state = (struct deflate_state *) arg;
state->seqno = 0;
inflateReset(&state->strm);
}
/*
* Decompress a Deflate-compressed packet.
*
* Because of patent problems, we return DECOMP_ERROR for errors
* found by inspecting the input data and for system problems, but
* DECOMP_FATALERROR for any errors which could possibly be said to
* be being detected "after" decompression. For DECOMP_ERROR,
* we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
* infringing a patent of Motorola's if we do, so we take CCP down
* instead.
*
* Given that the frame has the correct sequence number and a good FCS,
* errors such as invalid codes in the input most likely indicate a
* bug, so we return DECOMP_FATALERROR for them in order to turn off
* compression, even though they are detected by inspecting the input.
*/
static int
z_decompress(arg, mi, inlen, mo, outlenp)
void *arg;
u_char *mi, *mo;
int inlen, *outlenp;
{
struct deflate_state *state = (struct deflate_state *) arg;
u_char *rptr, *wptr;
int rlen, olen, ospace;
int seq, i, flush, r, decode_proto;
rptr = mi;
if (*rptr == 0)
++rptr;
++rptr;
/* Check the sequence number. */
seq = (rptr[0] << 8) + rptr[1];
rptr += 2;
if (seq != state->seqno) {
#if !DEFLATE_DEBUG
if (state->debug)
#endif
printf("z_decompress%d: bad seq # %d, expected %d\n",
state->unit, seq, state->seqno);
return DECOMP_ERROR;
}
++state->seqno;
/*
* Set up to call inflate.
*/
wptr = mo;
state->strm.next_in = rptr;
state->strm.avail_in = mi + inlen - rptr;
rlen = state->strm.avail_in + PPP_HDRLEN + DEFLATE_OVHD;
state->strm.next_out = wptr;
state->strm.avail_out = state->mru + 2;
r = inflate(&state->strm, Z_PACKET_FLUSH);
if (r != Z_OK) {
#if !DEFLATE_DEBUG
if (state->debug)
#endif
printf("z_decompress%d: inflate returned %d (%s)\n",
state->unit, r, (state->strm.msg? state->strm.msg: ""));
return DECOMP_FATALERROR;
}
olen = state->mru + 2 - state->strm.avail_out;
*outlenp = olen;
if ((wptr[0] & 1) != 0)
++olen; /* for suppressed protocol high byte */
olen += 2; /* for address, control */
#if DEFLATE_DEBUG
if (olen > state->mru + PPP_HDRLEN)
printf("ppp_deflate%d: exceeded mru (%d > %d)\n",
state->unit, olen, state->mru + PPP_HDRLEN);
#endif
state->stats.unc_bytes += olen;
state->stats.unc_packets++;
state->stats.comp_bytes += rlen;
state->stats.comp_packets++;
return DECOMP_OK;
}
/*
* Incompressible data has arrived - add it to the history.
*/
static void
z_incomp(arg, mi, mlen)
void *arg;
u_char *mi;
int mlen;
{
struct deflate_state *state = (struct deflate_state *) arg;
u_char *rptr;
int rlen, proto, r;
/*
* Check that the protocol is one we handle.
*/
rptr = mi;
proto = rptr[0];
if ((proto & 1) == 0)
proto = (proto << 8) + rptr[1];
if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
return;
++state->seqno;
if (rptr[0] == 0)
++rptr;
rlen = mi + mlen - rptr;
state->strm.next_in = rptr;
state->strm.avail_in = rlen;
r = inflateIncomp(&state->strm);
if (r != Z_OK) {
/* gak! */
#if !DEFLATE_DEBUG
if (state->debug)
#endif
printf("z_incomp%d: inflateIncomp returned %d (%s)\n",
state->unit, r, (state->strm.msg? state->strm.msg: ""));
return;
}
/*
* Update stats.
*/
if (proto <= 0xff)
++rlen;
rlen += 2;
state->stats.inc_bytes += rlen;
state->stats.inc_packets++;
state->stats.unc_bytes += rlen;
state->stats.unc_packets++;
}
#endif /* DO_DEFLATE */