[apple/xnu.git] / bsd / net / ppp_deflate.c

/*
 * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
 * 
 * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code 
 * as defined in and that are subject to the Apple Public Source License 
 * Version 2.0 (the 'License'). You may not use this file except in 
 * compliance with the License.  The rights granted to you under the 
 * License may not be used to create, or enable the creation or 
 * redistribution of, unlawful or unlicensed copies of an Apple operating 
 * system, or to circumvent, violate, or enable the circumvention or 
 * violation of, any terms of an Apple operating system software license 
 * agreement.
 *
 * Please obtain a copy of the License at 
 * http://www.opensource.apple.com/apsl/ and read it before using this 
 * file.
 *
 * The Original Code and all software distributed under the License are 
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
 * Please see the License for the specific language governing rights and 
 * limitations under the License.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
 */
/*
 * ppp_deflate.c - interface the zlib procedures for Deflate compression
 * and decompression (as used by gzip) to the PPP code.
 * This version is for use with mbufs on BSD-derived systems.
 *
 * 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.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <net/ppp_defs.h>
#include <net/zlib.h>

#define PACKETPTR	struct mbuf *
#include <net/ppp_comp.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(void *, u_int items, u_int size);
static void	z_free(void *, void *ptr);
static void	*z_comp_alloc(u_char *options, int opt_len);
static void	*z_decomp_alloc(u_char *options, int opt_len);
static void	z_comp_free(void *state);
static void	z_decomp_free(void *state);
static int	z_comp_init(void *state, u_char *options, int opt_len,
				 int unit, int hdrlen, int debug);
static int	z_decomp_init(void *state, u_char *options, int opt_len,
				     int unit, int hdrlen, int mru, int debug);
static int	z_compress(void *state, struct mbuf **mret,
				  struct mbuf *mp, int slen, int maxolen);
static void	z_incomp(void *state, struct mbuf *dmsg);
static int	z_decompress(void *state, struct mbuf *cmp, struct mbuf **dmpp);
static void	z_comp_reset(void *state);
static void	z_decomp_reset(void *state);
static void	z_comp_stats(void *state, struct compstat *stats);

/*
 * Procedures exported to if_ppp.c.
 */
struct compressor ppp_deflate = {
    CI_DEFLATE,			/* compress_proto */
    z_comp_alloc,		/* comp_alloc */
    z_comp_free,		/* comp_free */
    z_comp_init,		/* comp_init */
    z_comp_reset,		/* comp_reset */
    z_compress,			/* compress */
    z_comp_stats,		/* comp_stat */
    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 */
};

struct compressor ppp_deflate_draft = {
    CI_DEFLATE_DRAFT,		/* compress_proto */
    z_comp_alloc,		/* comp_alloc */
    z_comp_free,		/* comp_free */
    z_comp_init,		/* comp_init */
    z_comp_reset,		/* comp_reset */
    z_compress,			/* compress */
    z_comp_stats,		/* comp_stat */
    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.
 */
void *
z_alloc(notused, items, size)
    void *notused;
    u_int items, size;
{
    void *ptr;

    MALLOC(ptr, void *, items * size, M_DEVBUF, M_NOWAIT);
    return ptr;
}

void
z_free(notused, ptr)
    void *notused;
    void *ptr;
{
    FREE(ptr, M_DEVBUF);
}

/*
 * Allocate space for a compressor.
 */
static void *
z_comp_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[0] != CI_DEFLATE_DRAFT)
	|| 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;

    MALLOC(state, struct deflate_state *, sizeof(struct deflate_state),
	   M_DEVBUF, M_NOWAIT);
    if (state == NULL)
	return NULL;

    state->strm.next_in = NULL;
    state->strm.zalloc = z_alloc;
    state->strm.zfree = z_free;
    if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION, DEFLATE_METHOD_VAL,
		     -w_size, 8, Z_DEFAULT_STRATEGY) != Z_OK) {
	FREE(state, M_DEVBUF);
	return NULL;
    }

    state->w_size = w_size;
    bzero(&state->stats, sizeof(state->stats));
    return (void *) state;
}

static void
z_comp_free(arg)
    void *arg;
{
    struct deflate_state *state = (struct deflate_state *) arg;

    deflateEnd(&state->strm);
    FREE(state, M_DEVBUF);
}

static int
z_comp_init(arg, options, opt_len, unit, hdrlen, debug)
    void *arg;
    u_char *options;
    int opt_len, unit, hdrlen, debug;
{
    struct deflate_state *state = (struct deflate_state *) arg;

    if (opt_len < CILEN_DEFLATE
	|| (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
	|| 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;

    deflateReset(&state->strm);

    return 1;
}

static void
z_comp_reset(arg)
    void *arg;
{
    struct deflate_state *state = (struct deflate_state *) arg;

    state->seqno = 0;
    deflateReset(&state->strm);
}

int
z_compress(arg, mret, mp, orig_len, maxolen)
    void *arg;
    struct mbuf **mret;		/* compressed packet (out) */
    struct mbuf *mp;		/* uncompressed packet (in) */
    int orig_len, maxolen;
{
    struct deflate_state *state = (struct deflate_state *) arg;
    u_char *rptr, *wptr;
    int proto, olen, wspace, r, flush;
    struct mbuf *m;

    /*
     * Check that the protocol is in the range we handle.
     */
    rptr = mtod(mp, u_char *);
    proto = PPP_PROTOCOL(rptr);
    if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) {
	*mret = NULL;
	return orig_len;
    }

    /* Allocate one mbuf initially. */
    if (maxolen > orig_len)
	maxolen = orig_len;
    MGET(m, M_DONTWAIT, MT_DATA);
    *mret = m;
    if (m != NULL) {
	m->m_len = 0;
	if (maxolen + state->hdrlen > MLEN)
	    MCLGET(m, M_DONTWAIT);
	wspace = M_TRAILINGSPACE(m);
	if (state->hdrlen + PPP_HDRLEN + 2 < wspace) {
	    m->m_data += state->hdrlen;
	    wspace -= state->hdrlen;
	}
	wptr = mtod(m, u_char *);

	/*
	 * Copy over the PPP header and store the 2-byte sequence number.
	 */
	wptr[0] = PPP_ADDRESS(rptr);
	wptr[1] = PPP_CONTROL(rptr);
	wptr[2] = PPP_COMP >> 8;
	wptr[3] = PPP_COMP;
	wptr += PPP_HDRLEN;
	wptr[0] = state->seqno >> 8;
	wptr[1] = state->seqno;
	wptr += 2;
	state->strm.next_out = wptr;
	state->strm.avail_out = wspace - (PPP_HDRLEN + 2);
    } else {
	state->strm.next_out = NULL;
	state->strm.avail_out = 1000000;
	wptr = NULL;
	wspace = 0;
    }
    ++state->seqno;

    rptr += (proto > 0xff)? 2: 3;	/* skip 1st proto byte if 0 */
    state->strm.next_in = rptr;
    state->strm.avail_in = mtod(mp, u_char *) + mp->m_len - rptr;
    mp = mp->m_next;
    flush = (mp == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
    olen = 0;
    for (;;) {
	r = deflate(&state->strm, flush);
	if (r != Z_OK) {
	    printf("z_compress: deflate returned %d (%s)\n",
		   r, (state->strm.msg? state->strm.msg: ""));
	    break;
	}
	if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
	    break;		/* all done */
	if (state->strm.avail_in == 0 && mp != NULL) {
	    state->strm.next_in = mtod(mp, u_char *);
	    state->strm.avail_in = mp->m_len;
	    mp = mp->m_next;
	    if (mp == NULL)
		flush = Z_PACKET_FLUSH;
	}
	if (state->strm.avail_out == 0) {
	    if (m != NULL) {
		m->m_len = wspace;
		olen += wspace;
		MGET(m->m_next, M_DONTWAIT, MT_DATA);
		m = m->m_next;
		if (m != NULL) {
		    m->m_len = 0;
		    if (maxolen - olen > MLEN)
			MCLGET(m, M_DONTWAIT);
		    state->strm.next_out = mtod(m, u_char *);
		    state->strm.avail_out = wspace = M_TRAILINGSPACE(m);
		}
	    }
	    if (m == NULL) {
		state->strm.next_out = NULL;
		state->strm.avail_out = 1000000;
	    }
	}
    }
    if (m != NULL)
	olen += (m->m_len = wspace - state->strm.avail_out);

    /*
     * See if we managed to reduce the size of the packet.
     */
    if (m != NULL && olen < orig_len) {
	state->stats.comp_bytes += olen;
	state->stats.comp_packets++;
    } else {
	if (*mret != NULL) {
	    m_freem(*mret);
	    *mret = NULL;
	}
	state->stats.inc_bytes += orig_len;
	state->stats.inc_packets++;
	olen = orig_len;
    }
    state->stats.unc_bytes += orig_len;
    state->stats.unc_packets++;

    return olen;
}

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->inc_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[0] != CI_DEFLATE_DRAFT)
	|| 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;

    MALLOC(state, struct deflate_state *, sizeof(struct deflate_state),
	   M_DEVBUF, M_NOWAIT);
    if (state == NULL)
	return NULL;

    state->strm.next_out = NULL;
    state->strm.zalloc = z_alloc;
    state->strm.zfree = z_free;
    if (inflateInit2(&state->strm, -w_size) != Z_OK) {
	FREE(state, M_DEVBUF);
	return NULL;
    }

    state->w_size = w_size;
    bzero(&state->stats, 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, M_DEVBUF);
}

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[0] != CI_DEFLATE_DRAFT)
	|| 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.
 */
int
z_decompress(arg, mi, mop)
    void *arg;
    struct mbuf *mi, **mop;
{
    struct deflate_state *state = (struct deflate_state *) arg;
    struct mbuf *mo, *mo_head;
    u_char *rptr, *wptr;
    int rlen, olen, ospace;
    int seq, i, flush, r, decode_proto;
    u_char hdr[PPP_HDRLEN + DEFLATE_OVHD];

    *mop = NULL;
    rptr = mtod(mi, u_char *);
    rlen = mi->m_len;
    for (i = 0; i < PPP_HDRLEN + DEFLATE_OVHD; ++i) {
	while (rlen <= 0) {
	    mi = mi->m_next;
	    if (mi == NULL)
		return DECOMP_ERROR;
	    rptr = mtod(mi, u_char *);
	    rlen = mi->m_len;
	}
	hdr[i] = *rptr++;
	--rlen;
    }

    /* Check the sequence number. */
    seq = (hdr[PPP_HDRLEN] << 8) + hdr[PPP_HDRLEN+1];
    if (seq != state->seqno) {
	if (state->debug)
	    printf("z_decompress%d: bad seq # %d, expected %d\n",
		   state->unit, seq, state->seqno);
	return DECOMP_ERROR;
    }
    ++state->seqno;

    /* Allocate an output mbuf. */
    MGETHDR(mo, M_DONTWAIT, MT_DATA);
    if (mo == NULL)
	return DECOMP_ERROR;
    mo_head = mo;
    mo->m_len = 0;
    mo->m_next = NULL;
    MCLGET(mo, M_DONTWAIT);
    ospace = M_TRAILINGSPACE(mo);
    if (state->hdrlen + PPP_HDRLEN < ospace) {
	mo->m_data += state->hdrlen;
	ospace -= state->hdrlen;
    }

    /*
     * Fill in the first part of the PPP header.  The protocol field
     * comes from the decompressed data.
     */
    wptr = mtod(mo, u_char *);
    wptr[0] = PPP_ADDRESS(hdr);
    wptr[1] = PPP_CONTROL(hdr);
    wptr[2] = 0;

    /*
     * Set up to call inflate.  We set avail_out to 1 initially so we can
     * look at the first byte of the output and decide whether we have
     * a 1-byte or 2-byte protocol field.
     */
    state->strm.next_in = rptr;
    state->strm.avail_in = rlen;
    mi = mi->m_next;
    flush = (mi == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
    rlen += PPP_HDRLEN + DEFLATE_OVHD;
    state->strm.next_out = wptr + 3;
    state->strm.avail_out = 1;
    decode_proto = 1;
    olen = PPP_HDRLEN;

    /*
     * Call inflate, supplying more input or output as needed.
     */
    for (;;) {
	r = inflate(&state->strm, 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: ""));
	    m_freem(mo_head);
	    return DECOMP_FATALERROR;
	}
	if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
	    break;		/* all done */
	if (state->strm.avail_in == 0 && mi != NULL) {
	    state->strm.next_in = mtod(mi, u_char *);
	    state->strm.avail_in = mi->m_len;
	    rlen += mi->m_len;
	    mi = mi->m_next;
	    if (mi == NULL)
		flush = Z_PACKET_FLUSH;
	}
	if (state->strm.avail_out == 0) {
	    if (decode_proto) {
		state->strm.avail_out = ospace - PPP_HDRLEN;
		if ((wptr[3] & 1) == 0) {
		    /* 2-byte protocol field */
		    wptr[2] = wptr[3];
		    --state->strm.next_out;
		    ++state->strm.avail_out;
		    --olen;
		}
		decode_proto = 0;
	    } else {
		mo->m_len = ospace;
		olen += ospace;
		MGET(mo->m_next, M_DONTWAIT, MT_DATA);
		mo = mo->m_next;
		if (mo == NULL) {
		    m_freem(mo_head);
		    return DECOMP_ERROR;
		}
		MCLGET(mo, M_DONTWAIT);
		state->strm.next_out = mtod(mo, u_char *);
		state->strm.avail_out = ospace = M_TRAILINGSPACE(mo);
	    }
	}
    }
    if (decode_proto) {
	m_freem(mo_head);
	return DECOMP_ERROR;
    }
    olen += (mo->m_len = ospace - state->strm.avail_out);
#if DEFLATE_DEBUG
    if (state->debug && 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++;

    *mop = mo_head;
    return DECOMP_OK;
}

/*
 * Incompressible data has arrived - add it to the history.
 */
static void
z_incomp(arg, mi)
    void *arg;
    struct mbuf *mi;
{
    struct deflate_state *state = (struct deflate_state *) arg;
    u_char *rptr;
    int rlen, proto, r;

    /*
     * Check that the protocol is one we handle.
     */
    rptr = mtod(mi, u_char *);
    proto = PPP_PROTOCOL(rptr);
    if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
	return;

    ++state->seqno;

    /*
     * Iterate through the mbufs, adding the characters in them
     * to the decompressor's history.  For the first mbuf, we start
     * at the either the 1st or 2nd byte of the protocol field,
     * depending on whether the protocol value is compressible.
     */
    rlen = mi->m_len;
    state->strm.next_in = rptr + 3;
    state->strm.avail_in = rlen - 3;
    if (proto > 0xff) {
	--state->strm.next_in;
	++state->strm.avail_in;
    }
    for (;;) {
	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;
	}
	mi = mi->m_next;
	if (mi == NULL)
	    break;
	state->strm.next_in = mtod(mi, u_char *);
	state->strm.avail_in = mi->m_len;
	rlen += mi->m_len;
    }

    /*
     * Update stats.
     */
    state->stats.inc_bytes += rlen;
    state->stats.inc_packets++;
    state->stats.unc_bytes += rlen;
    state->stats.unc_packets++;
}

#endif /* DO_DEFLATE */
Commit	Line	Data
1c79356b	1	/*
8ad349bb	2	* Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
1c79356b	3	*
8ad349bb	4	* @APPLE_LICENSE_OSREFERENCE_HEADER_START@
1c79356b	5	*
8ad349bb A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the
	10	* License may not be used to create, or enable the creation or
	11	* redistribution of, unlawful or unlicensed copies of an Apple operating
	12	* system, or to circumvent, violate, or enable the circumvention or
	13	* violation of, any terms of an Apple operating system software license
	14	* agreement.
	15	*
	16	* Please obtain a copy of the License at
	17	* http://www.opensource.apple.com/apsl/ and read it before using this
	18	* file.
	19	*
	20	* The Original Code and all software distributed under the License are
	21	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	22	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	23	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	24	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	25	* Please see the License for the specific language governing rights and
	26	* limitations under the License.
	27	*
	28	* @APPLE_LICENSE_OSREFERENCE_HEADER_END@
1c79356b A	29	*/
	30	/*
	31	* ppp_deflate.c - interface the zlib procedures for Deflate compression
	32	* and decompression (as used by gzip) to the PPP code.
	33	* This version is for use with mbufs on BSD-derived systems.
	34	*
	35	* Copyright (c) 1994 The Australian National University.
	36	* All rights reserved.
	37	*
	38	* Permission to use, copy, modify, and distribute this software and its
	39	* documentation is hereby granted, provided that the above copyright
	40	* notice appears in all copies. This software is provided without any
	41	* warranty, express or implied. The Australian National University
	42	* makes no representations about the suitability of this software for
	43	* any purpose.
	44	*
	45	* IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
	46	* PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
	47	* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
	48	* THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY
	49	* OF SUCH DAMAGE.
	50	*
	51	* THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
	52	* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
	53	* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
	54	* ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
	55	* OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
	56	* OR MODIFICATIONS.
	57	*/
	58
	59	#include <sys/param.h>
	60	#include <sys/systm.h>
	61	#include <sys/malloc.h>
	62	#include <sys/mbuf.h>
	63	#include <net/ppp_defs.h>
	64	#include <net/zlib.h>
	65
	66	#define PACKETPTR struct mbuf *
	67	#include <net/ppp_comp.h>
	68
	69	#if DO_DEFLATE
	70
	71	#define DEFLATE_DEBUG 1
	72
	73	/*
	74	* State for a Deflate (de)compressor.
	75	*/
	76	struct deflate_state {
	77	int seqno;
	78	int w_size;
	79	int unit;
	80	int hdrlen;
	81	int mru;
	82	int debug;
	83	z_stream strm;
	84	struct compstat stats;
	85	};
	86
	87	#define DEFLATE_OVHD 2 /* Deflate overhead/packet */
	88
91447636 A	89	static void z_alloc(void , u_int items, u_int size);
	90	static void z_free(void , void ptr);
	91	static void z_comp_alloc(u_char options, int opt_len);
	92	static void z_decomp_alloc(u_char options, int opt_len);
	93	static void z_comp_free(void *state);
	94	static void z_decomp_free(void *state);
	95	static int z_comp_init(void state, u_char options, int opt_len,
	96	int unit, int hdrlen, int debug);
	97	static int z_decomp_init(void state, u_char options, int opt_len,
	98	int unit, int hdrlen, int mru, int debug);
	99	static int z_compress(void state, struct mbuf *mret,
	100	struct mbuf *mp, int slen, int maxolen);
	101	static void z_incomp(void state, struct mbuf dmsg);
	102	static int z_decompress(void state, struct mbuf cmp, struct mbuf **dmpp);
	103	static void z_comp_reset(void *state);
	104	static void z_decomp_reset(void *state);
	105	static void z_comp_stats(void state, struct compstat stats);
1c79356b A	106
	107	/*
	108	* Procedures exported to if_ppp.c.
	109	*/
	110	struct compressor ppp_deflate = {
	111	CI_DEFLATE, /* compress_proto */
	112	z_comp_alloc, /* comp_alloc */
	113	z_comp_free, /* comp_free */
	114	z_comp_init, /* comp_init */
	115	z_comp_reset, /* comp_reset */
	116	z_compress, /* compress */
	117	z_comp_stats, /* comp_stat */
	118	z_decomp_alloc, /* decomp_alloc */
	119	z_decomp_free, /* decomp_free */
	120	z_decomp_init, /* decomp_init */
	121	z_decomp_reset, /* decomp_reset */
	122	z_decompress, /* decompress */
	123	z_incomp, /* incomp */
	124	z_comp_stats, /* decomp_stat */
	125	};
	126
	127	struct compressor ppp_deflate_draft = {
	128	CI_DEFLATE_DRAFT, /* compress_proto */
	129	z_comp_alloc, /* comp_alloc */
	130	z_comp_free, /* comp_free */
	131	z_comp_init, /* comp_init */
	132	z_comp_reset, /* comp_reset */
	133	z_compress, /* compress */
	134	z_comp_stats, /* comp_stat */
	135	z_decomp_alloc, /* decomp_alloc */
	136	z_decomp_free, /* decomp_free */
	137	z_decomp_init, /* decomp_init */
	138	z_decomp_reset, /* decomp_reset */
	139	z_decompress, /* decompress */
	140	z_incomp, /* incomp */
	141	z_comp_stats, /* decomp_stat */
	142	};
	143
	144	/*
	145	* Space allocation and freeing routines for use by zlib routines.
	146	*/
	147	void *
	148	z_alloc(notused, items, size)
	149	void *notused;
	150	u_int items, size;
	151	{
	152	void *ptr;
	153
	154	MALLOC(ptr, void , items size, M_DEVBUF, M_NOWAIT);
	155	return ptr;
	156	}
	157
	158	void
	159	z_free(notused, ptr)
	160	void *notused;
	161	void *ptr;
	162	{
	163	FREE(ptr, M_DEVBUF);
	164	}
	165
	166	/*
	167	* Allocate space for a compressor.
	168	*/
	169	static void *
170	z_comp_alloc(options, opt_len)
171	u_char *options;
172	int opt_len;
173	{
174	struct deflate_state *state;
175	int w_size;
176
177	if (opt_len != CILEN_DEFLATE
178	\|\| (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
179	\|\| options[1] != CILEN_DEFLATE
180	\|\| DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
181	\|\| options[3] != DEFLATE_CHK_SEQUENCE)
182	return NULL;
183	w_size = DEFLATE_SIZE(options[2]);
184	if (w_size < DEFLATE_MIN_SIZE \|\| w_size > DEFLATE_MAX_SIZE)
185	return NULL;
186
187	MALLOC(state, struct deflate_state *, sizeof(struct deflate_state),
188	M_DEVBUF, M_NOWAIT);
189	if (state == NULL)
190	return NULL;
191
192	state->strm.next_in = NULL;
193	state->strm.zalloc = z_alloc;
194	state->strm.zfree = z_free;
195	if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION, DEFLATE_METHOD_VAL,
196	-w_size, 8, Z_DEFAULT_STRATEGY) != Z_OK) {
197	FREE(state, M_DEVBUF);
198	return NULL;
199	}
200
201	state->w_size = w_size;
202	bzero(&state->stats, sizeof(state->stats));
203	return (void *) state;
204	}
205
206	static void
207	z_comp_free(arg)
208	void *arg;
209	{
210	struct deflate_state state = (struct deflate_state ) arg;
211
212	deflateEnd(&state->strm);
213	FREE(state, M_DEVBUF);
214	}
215
216	static int
217	z_comp_init(arg, options, opt_len, unit, hdrlen, debug)
218	void *arg;
219	u_char *options;
220	int opt_len, unit, hdrlen, debug;
221	{
222	struct deflate_state state = (struct deflate_state ) arg;
223
224	if (opt_len < CILEN_DEFLATE
225	\|\| (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
226	\|\| options[1] != CILEN_DEFLATE
227	\|\| DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
228	\|\| DEFLATE_SIZE(options[2]) != state->w_size
229	\|\| options[3] != DEFLATE_CHK_SEQUENCE)
230	return 0;
231
232	state->seqno = 0;
233	state->unit = unit;
234	state->hdrlen = hdrlen;
235	state->debug = debug;
236
237	deflateReset(&state->strm);
238
239	return 1;
240	}
241
242	static void
243	z_comp_reset(arg)
244	void *arg;
245	{
246	struct deflate_state state = (struct deflate_state ) arg;
247
248	state->seqno = 0;
249	deflateReset(&state->strm);
250	}
251
252	int
253	z_compress(arg, mret, mp, orig_len, maxolen)
254	void *arg;
255	struct mbuf *mret; / compressed packet (out) */
256	struct mbuf mp; / uncompressed packet (in) */
257	int orig_len, maxolen;
258	{
259	struct deflate_state state = (struct deflate_state ) arg;
260	u_char rptr, wptr;
261	int proto, olen, wspace, r, flush;
262	struct mbuf *m;
263
264	/*
265	* Check that the protocol is in the range we handle.
266	*/
267	rptr = mtod(mp, u_char *);
268	proto = PPP_PROTOCOL(rptr);
269	if (proto > 0x3fff \|\| proto == 0xfd \|\| proto == 0xfb) {
270	*mret = NULL;
271	return orig_len;
272	}
273
274	/* Allocate one mbuf initially. */
275	if (maxolen > orig_len)
276	maxolen = orig_len;
277	MGET(m, M_DONTWAIT, MT_DATA);
278	*mret = m;
279	if (m != NULL) {
280	m->m_len = 0;
281	if (maxolen + state->hdrlen > MLEN)
282	MCLGET(m, M_DONTWAIT);
283	wspace = M_TRAILINGSPACE(m);
284	if (state->hdrlen + PPP_HDRLEN + 2 < wspace) {
285	m->m_data += state->hdrlen;
286	wspace -= state->hdrlen;
287	}
288	wptr = mtod(m, u_char *);
289
290	/*
291	* Copy over the PPP header and store the 2-byte sequence number.
292	*/
293	wptr[0] = PPP_ADDRESS(rptr);
294	wptr[1] = PPP_CONTROL(rptr);
295	wptr[2] = PPP_COMP >> 8;
296	wptr[3] = PPP_COMP;
297	wptr += PPP_HDRLEN;
298	wptr[0] = state->seqno >> 8;
299	wptr[1] = state->seqno;
300	wptr += 2;
301	state->strm.next_out = wptr;
302	state->strm.avail_out = wspace - (PPP_HDRLEN + 2);
303	} else {
304	state->strm.next_out = NULL;
305	state->strm.avail_out = 1000000;
306	wptr = NULL;
307	wspace = 0;
308	}
309	++state->seqno;
310
311	rptr += (proto > 0xff)? 2: 3; /* skip 1st proto byte if 0 */
312	state->strm.next_in = rptr;
313	state->strm.avail_in = mtod(mp, u_char *) + mp->m_len - rptr;
314	mp = mp->m_next;
315	flush = (mp == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
316	olen = 0;
317	for (;;) {
318	r = deflate(&state->strm, flush);
319	if (r != Z_OK) {
320	printf("z_compress: deflate returned %d (%s)\n",
321	r, (state->strm.msg? state->strm.msg: ""));
322	break;
323	}
324	if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
325	break; /* all done */
326	if (state->strm.avail_in == 0 && mp != NULL) {
327	state->strm.next_in = mtod(mp, u_char *);
328	state->strm.avail_in = mp->m_len;
329	mp = mp->m_next;
330	if (mp == NULL)
331	flush = Z_PACKET_FLUSH;
332	}
333	if (state->strm.avail_out == 0) {
334	if (m != NULL) {
335	m->m_len = wspace;
336	olen += wspace;
337	MGET(m->m_next, M_DONTWAIT, MT_DATA);
338	m = m->m_next;
339	if (m != NULL) {
340	m->m_len = 0;
341	if (maxolen - olen > MLEN)
342	MCLGET(m, M_DONTWAIT);
343	state->strm.next_out = mtod(m, u_char *);
344	state->strm.avail_out = wspace = M_TRAILINGSPACE(m);
345	}
346	}
347	if (m == NULL) {
348	state->strm.next_out = NULL;
349	state->strm.avail_out = 1000000;
350	}
351	}
352	}
353	if (m != NULL)
354	olen += (m->m_len = wspace - state->strm.avail_out);
355
356	/*
357	* See if we managed to reduce the size of the packet.
358	*/
359	if (m != NULL && olen < orig_len) {
360	state->stats.comp_bytes += olen;
361	state->stats.comp_packets++;
362	} else {
363	if (*mret != NULL) {
364	m_freem(*mret);
365	*mret = NULL;
366	}
367	state->stats.inc_bytes += orig_len;
368	state->stats.inc_packets++;
369	olen = orig_len;
370	}
371	state->stats.unc_bytes += orig_len;
372	state->stats.unc_packets++;
373
374	return olen;
375	}
376
377	static void
378	z_comp_stats(arg, stats)
379	void *arg;
380	struct compstat *stats;
381	{
382	struct deflate_state state = (struct deflate_state ) arg;
383	u_int out;
384
385	*stats = state->stats;
386	stats->ratio = stats->unc_bytes;
387	out = stats->comp_bytes + stats->inc_bytes;
388	if (stats->ratio <= 0x7ffffff)
389	stats->ratio <<= 8;
390	else
391	out >>= 8;
392	if (out != 0)
393	stats->ratio /= out;
394	}
395
396	/*
397	* Allocate space for a decompressor.
398	*/
399	static void *
400	z_decomp_alloc(options, opt_len)
401	u_char *options;
402	int opt_len;
403	{
404	struct deflate_state *state;
405	int w_size;
406
407	if (opt_len != CILEN_DEFLATE
408	\|\| (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
409	\|\| options[1] != CILEN_DEFLATE
410	\|\| DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
411	\|\| options[3] != DEFLATE_CHK_SEQUENCE)
412	return NULL;
413	w_size = DEFLATE_SIZE(options[2]);
414	if (w_size < DEFLATE_MIN_SIZE \|\| w_size > DEFLATE_MAX_SIZE)
415	return NULL;
416
417	MALLOC(state, struct deflate_state *, sizeof(struct deflate_state),
418	M_DEVBUF, M_NOWAIT);
419	if (state == NULL)
420	return NULL;
421
422	state->strm.next_out = NULL;
423	state->strm.zalloc = z_alloc;
424	state->strm.zfree = z_free;
425	if (inflateInit2(&state->strm, -w_size) != Z_OK) {
426	FREE(state, M_DEVBUF);
427	return NULL;
428	}
429
430	state->w_size = w_size;
431	bzero(&state->stats, sizeof(state->stats));
432	return (void *) state;
433	}
434
435	static void
436	z_decomp_free(arg)
437	void *arg;
438	{
439	struct deflate_state state = (struct deflate_state ) arg;
440
441	inflateEnd(&state->strm);
442	FREE(state, M_DEVBUF);
443	}
444
445	static int
446	z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
447	void *arg;
448	u_char *options;
449	int opt_len, unit, hdrlen, mru, debug;
450	{
451	struct deflate_state state = (struct deflate_state ) arg;
452
453	if (opt_len < CILEN_DEFLATE
454	\|\| (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
455	\|\| options[1] != CILEN_DEFLATE
456	\|\| DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
457	\|\| DEFLATE_SIZE(options[2]) != state->w_size
458	\|\| options[3] != DEFLATE_CHK_SEQUENCE)
459	return 0;
460
461	state->seqno = 0;
462	state->unit = unit;
463	state->hdrlen = hdrlen;
464	state->debug = debug;
465	state->mru = mru;
466
467	inflateReset(&state->strm);
468
469	return 1;
470	}
471
472	static void
473	z_decomp_reset(arg)
474	void *arg;
475	{
476	struct deflate_state state = (struct deflate_state ) arg;
477
478	state->seqno = 0;
479	inflateReset(&state->strm);
480	}
481
482	/*
483	* Decompress a Deflate-compressed packet.
484	*
485	* Because of patent problems, we return DECOMP_ERROR for errors
486	* found by inspecting the input data and for system problems, but
487	* DECOMP_FATALERROR for any errors which could possibly be said to
488	* be being detected "after" decompression. For DECOMP_ERROR,
489	* we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
490	* infringing a patent of Motorola's if we do, so we take CCP down
491	* instead.
492	*
493	* Given that the frame has the correct sequence number and a good FCS,
494	* errors such as invalid codes in the input most likely indicate a
495	* bug, so we return DECOMP_FATALERROR for them in order to turn off
496	* compression, even though they are detected by inspecting the input.
497	*/
498	int
499	z_decompress(arg, mi, mop)
500	void *arg;
501	struct mbuf mi, *mop;
502	{
503	struct deflate_state state = (struct deflate_state ) arg;
504	struct mbuf mo, mo_head;
505	u_char rptr, wptr;
506	int rlen, olen, ospace;
507	int seq, i, flush, r, decode_proto;
508	u_char hdr[PPP_HDRLEN + DEFLATE_OVHD];
509
510	*mop = NULL;
511	rptr = mtod(mi, u_char *);
512	rlen = mi->m_len;
513	for (i = 0; i < PPP_HDRLEN + DEFLATE_OVHD; ++i) {
514	while (rlen <= 0) {
515	mi = mi->m_next;
516	if (mi == NULL)
517	return DECOMP_ERROR;
518	rptr = mtod(mi, u_char *);
519	rlen = mi->m_len;
520	}
521	hdr[i] = *rptr++;
522	--rlen;
523	}
524
525	/* Check the sequence number. */
526	seq = (hdr[PPP_HDRLEN] << 8) + hdr[PPP_HDRLEN+1];
527	if (seq != state->seqno) {
528	if (state->debug)
529	printf("z_decompress%d: bad seq # %d, expected %d\n",
530	state->unit, seq, state->seqno);
531	return DECOMP_ERROR;
532	}
533	++state->seqno;
534
535	/* Allocate an output mbuf. */
536	MGETHDR(mo, M_DONTWAIT, MT_DATA);
537	if (mo == NULL)
538	return DECOMP_ERROR;
539	mo_head = mo;
540	mo->m_len = 0;
541	mo->m_next = NULL;
542	MCLGET(mo, M_DONTWAIT);
543	ospace = M_TRAILINGSPACE(mo);
544	if (state->hdrlen + PPP_HDRLEN < ospace) {
545	mo->m_data += state->hdrlen;
546	ospace -= state->hdrlen;
547	}
548
549	/*
550	* Fill in the first part of the PPP header. The protocol field
551	* comes from the decompressed data.
552	*/
553	wptr = mtod(mo, u_char *);
554	wptr[0] = PPP_ADDRESS(hdr);
555	wptr[1] = PPP_CONTROL(hdr);
556	wptr[2] = 0;
557
558	/*
559	* Set up to call inflate. We set avail_out to 1 initially so we can
560	* look at the first byte of the output and decide whether we have
561	* a 1-byte or 2-byte protocol field.
562	*/
563	state->strm.next_in = rptr;
564	state->strm.avail_in = rlen;
565	mi = mi->m_next;
566	flush = (mi == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
567	rlen += PPP_HDRLEN + DEFLATE_OVHD;
568	state->strm.next_out = wptr + 3;
569	state->strm.avail_out = 1;
570	decode_proto = 1;
571	olen = PPP_HDRLEN;
572
573	/*
574	* Call inflate, supplying more input or output as needed.
575	*/
576	for (;;) {
577	r = inflate(&state->strm, flush);
578	if (r != Z_OK) {
579	#if !DEFLATE_DEBUG
580	if (state->debug)
581	#endif
582	printf("z_decompress%d: inflate returned %d (%s)\n",
583	state->unit, r, (state->strm.msg? state->strm.msg: ""));
584	m_freem(mo_head);
585	return DECOMP_FATALERROR;
586	}
587	if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
588	break; /* all done */
589	if (state->strm.avail_in == 0 && mi != NULL) {
590	state->strm.next_in = mtod(mi, u_char *);
591	state->strm.avail_in = mi->m_len;
592	rlen += mi->m_len;
593	mi = mi->m_next;
594	if (mi == NULL)
595	flush = Z_PACKET_FLUSH;
596	}
597	if (state->strm.avail_out == 0) {
598	if (decode_proto) {
599	state->strm.avail_out = ospace - PPP_HDRLEN;
600	if ((wptr[3] & 1) == 0) {
601	/* 2-byte protocol field */
602	wptr[2] = wptr[3];
603	--state->strm.next_out;
604	++state->strm.avail_out;
605	--olen;
606	}
607	decode_proto = 0;
608	} else {
609	mo->m_len = ospace;
610	olen += ospace;
611	MGET(mo->m_next, M_DONTWAIT, MT_DATA);
612	mo = mo->m_next;
613	if (mo == NULL) {
614	m_freem(mo_head);
615	return DECOMP_ERROR;
616	}
617	MCLGET(mo, M_DONTWAIT);
618	state->strm.next_out = mtod(mo, u_char *);
619	state->strm.avail_out = ospace = M_TRAILINGSPACE(mo);
620	}
621	}
622	}
623	if (decode_proto) {
624	m_freem(mo_head);
625	return DECOMP_ERROR;
626	}
627	olen += (mo->m_len = ospace - state->strm.avail_out);
628	#if DEFLATE_DEBUG
629	if (state->debug && olen > state->mru + PPP_HDRLEN)
630	printf("ppp_deflate%d: exceeded mru (%d > %d)\n",
631	state->unit, olen, state->mru + PPP_HDRLEN);
632	#endif
633
634	state->stats.unc_bytes += olen;
635	state->stats.unc_packets++;
636	state->stats.comp_bytes += rlen;
637	state->stats.comp_packets++;
638
639	*mop = mo_head;
640	return DECOMP_OK;
641	}
642
643	/*
644	* Incompressible data has arrived - add it to the history.
645	*/
646	static void
647	z_incomp(arg, mi)
648	void *arg;
649	struct mbuf *mi;
650	{
651	struct deflate_state state = (struct deflate_state ) arg;
652	u_char *rptr;
653	int rlen, proto, r;
654
655	/*
656	* Check that the protocol is one we handle.
657	*/
658	rptr = mtod(mi, u_char *);
659	proto = PPP_PROTOCOL(rptr);
660	if (proto > 0x3fff \|\| proto == 0xfd \|\| proto == 0xfb)
661	return;
662
663	++state->seqno;
664
665	/*
666	* Iterate through the mbufs, adding the characters in them
667	* to the decompressor's history. For the first mbuf, we start
668	* at the either the 1st or 2nd byte of the protocol field,
669	* depending on whether the protocol value is compressible.
670	*/
671	rlen = mi->m_len;
672	state->strm.next_in = rptr + 3;
673	state->strm.avail_in = rlen - 3;
674	if (proto > 0xff) {
675	--state->strm.next_in;
676	++state->strm.avail_in;
677	}
678	for (;;) {
679	r = inflateIncomp(&state->strm);
680	if (r != Z_OK) {
681	/* gak! */
682	#if !DEFLATE_DEBUG
683	if (state->debug)
684	#endif
685	printf("z_incomp%d: inflateIncomp returned %d (%s)\n",
686	state->unit, r, (state->strm.msg? state->strm.msg: ""));
687	return;
688	}
689	mi = mi->m_next;
690	if (mi == NULL)
691	break;
692	state->strm.next_in = mtod(mi, u_char *);
693	state->strm.avail_in = mi->m_len;
694	rlen += mi->m_len;
695	}
696
697	/*
698	* Update stats.
699	*/
700	state->stats.inc_bytes += rlen;
701	state->stats.inc_packets++;
702	state->stats.unc_bytes += rlen;
703	state->stats.unc_packets++;
704	}
705
706	#endif /* DO_DEFLATE */