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//==========================================================================

//

//      src/ppp_deflate.c

//

//==========================================================================

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//==========================================================================

/* $FreeBSD: src/sys/net/ppp_deflate.c,v 1.12 1999/08/28 00:48:26 peter Exp $   */

/*

 * 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.

 */

#define _KERNEL

#include <sys/param.h>

//#include <sys/systm.h>

#include <sys/malloc.h>

#include <sys/mbuf.h>

#include <cyg/ppp/net/ppp_defs.h>

#include <cyg/ppp/net/zlib.h>

#define PACKETPTR       struct mbuf *

#include <cyg/ppp/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 __P((void *, u_int items, u_int size));

static void     z_free __P((void *, void *ptr));

static void     *z_comp_alloc __P((u_char *options, int opt_len));

static void     *z_decomp_alloc __P((u_char *options, int opt_len));

static void     z_comp_free __P((void *state));

static void     z_decomp_free __P((void *state));

static int      z_comp_init __P((void *state, u_char *options, int opt_len,

                                 int unit, int hdrlen, int debug));

static int      z_decomp_init __P((void *state, u_char *options, int opt_len,

                                     int unit, int hdrlen, int mru, int debug));

static int      z_compress __P((void *state, struct mbuf **mret,

                                  struct mbuf *mp, int slen, int maxolen));

static void     z_incomp __P((void *state, struct mbuf *dmsg));

static int      z_decompress __P((void *state, struct mbuf *cmp,

                                    struct mbuf **dmpp));

static void     z_comp_reset __P((void *state));

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_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