* add p cc

[mascara-docs.git] / i386 / linux / linux-2.3.21 / drivers / net / ppp_deflate.c

/*
 *  ==FILEVERSION 980319==
 *
 * 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 Linux kernel 1.3.X.
 *
 * 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.
 *
 * From: deflate.c,v 1.1 1996/01/18 03:17:48 paulus Exp
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/malloc.h>
#include <linux/vmalloc.h>
#include <linux/errno.h>
#include <linux/string.h>       /* used in new tty drivers */
#include <linux/signal.h>       /* used in new tty drivers */

#include <asm/system.h>

#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/inet.h>
#include <linux/ioctl.h>

#include <linux/ppp_defs.h>
#include <linux/ppp-comp.h>

#include "zlib.c"

/*
 * State for a Deflate (de)compressor.
 */
struct ppp_deflate_state {
    int         seqno;
    int         w_size;
    int         unit;
    int         mru;
    int         debug;
    z_stream    strm;
    struct compstat stats;
};

#define DEFLATE_OVHD    2               /* Deflate overhead/packet */

static void     *zalloc __P((void *, unsigned int items, unsigned int size));
static void     *zalloc_init __P((void *, unsigned int items,
                                  unsigned int size));
static void     zfree __P((void *, void *ptr));
static void     *z_comp_alloc __P((unsigned char *options, int opt_len));
static void     *z_decomp_alloc __P((unsigned 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, unsigned char *options,
                                 int opt_len,
                                 int unit, int hdrlen, int debug));
static int      z_decomp_init __P((void *state, unsigned char *options,
                                   int opt_len,
                                   int unit, int hdrlen, int mru, int debug));
static int      z_compress __P((void *state, unsigned char *rptr,
                                unsigned char *obuf,
                                int isize, int osize));
static void     z_incomp __P((void *state, unsigned char *ibuf, int icnt));
static int      z_decompress __P((void *state, unsigned char *ibuf,
                                int isize, unsigned char *obuf, int osize));
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));

struct chunk_header {
        int valloced;           /* allocated with valloc, not kmalloc */
        int guard;              /* check for overwritten header */
};

#define GUARD_MAGIC     0x77a8011a
#define MIN_VMALLOC     2048    /* use kmalloc for blocks < this */

/*
 * Space allocation and freeing routines for use by zlib routines.
 */
void
zfree(arg, ptr)
    void *arg;
    void *ptr;
{
        struct chunk_header *hdr = ((struct chunk_header *)ptr) - 1;

        if (hdr->guard != GUARD_MAGIC) {
                printk(KERN_WARNING "zfree: header corrupted (%x %x) at %p\n",
                       hdr->valloced, hdr->guard, hdr);
                return;
        }
        if (hdr->valloced)
                vfree(hdr);
        else
                kfree(hdr);
}

void *
zalloc(arg, items, size)
    void *arg;
    unsigned int items, size;
{
        struct chunk_header *hdr;
        unsigned nbytes;

        nbytes = items * size + sizeof(*hdr);
        hdr = kmalloc(nbytes, GFP_ATOMIC);
        if (hdr == 0)
                return 0;
        hdr->valloced = 0;
        hdr->guard = GUARD_MAGIC;
        return (void *) (hdr + 1);
}

void *
zalloc_init(arg, items, size)
    void *arg;
    unsigned int items, size;
{
        struct chunk_header *hdr;
        unsigned nbytes;

        nbytes = items * size + sizeof(*hdr);
        if (nbytes >= MIN_VMALLOC)
                hdr = vmalloc(nbytes);
        else
                hdr = kmalloc(nbytes, GFP_KERNEL);
        if (hdr == 0)
                return 0;
        hdr->valloced = nbytes >= MIN_VMALLOC;
        hdr->guard = GUARD_MAGIC;
        return (void *) (hdr + 1);
}

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

        if (state) {
                deflateEnd(&state->strm);
                kfree(state);
                MOD_DEC_USE_COUNT;
        }
}

/*
 * Allocate space for a compressor.
 */
static void *
z_comp_alloc(options, opt_len)
    unsigned char *options;
    int opt_len;
{
        struct ppp_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;

        state = (struct ppp_deflate_state *) kmalloc(sizeof(*state), GFP_KERNEL);
        if (state == NULL)
                return NULL;

        MOD_INC_USE_COUNT;
        memset (state, 0, sizeof (struct ppp_deflate_state));
        state->strm.next_in = NULL;
        state->strm.zalloc  = zalloc_init;
        state->strm.zfree   = zfree;
        state->w_size       = w_size;

        if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION,
                         DEFLATE_METHOD_VAL, -w_size, 8, Z_DEFAULT_STRATEGY)
            != Z_OK)
                goto out_free;
        state->strm.zalloc = zalloc;
        return (void *) state;

out_free:
        z_comp_free(state);
        MOD_DEC_USE_COUNT;
        return NULL;
}

static int
z_comp_init(arg, options, opt_len, unit, hdrlen, debug)
    void *arg;
    unsigned char *options;
    int opt_len, unit, hdrlen, debug;
{
        struct ppp_deflate_state *state = (struct ppp_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->debug = debug;

        deflateReset(&state->strm);

        return 1;
}

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

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

int
z_compress(arg, rptr, obuf, isize, osize)
    void *arg;
    unsigned char *rptr;        /* uncompressed packet (in) */
    unsigned char *obuf;        /* compressed packet (out) */
    int isize, osize;
{
        struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
        int r, proto, off, olen, oavail;
        unsigned char *wptr;

        /*
         * Check that the protocol is in the range we handle.
         */
        proto = PPP_PROTOCOL(rptr);
        if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
                return 0;

        /* Don't generate compressed packets which are larger than
           the uncompressed packet. */
        if (osize > isize)
                osize = isize;

        wptr = obuf;

        /*
         * 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 += DEFLATE_OVHD;
        olen = PPP_HDRLEN + DEFLATE_OVHD;
        state->strm.next_out = wptr;
        state->strm.avail_out = oavail = osize - olen;
        ++state->seqno;

        off = (proto > 0xff) ? 2 : 3;   /* skip 1st proto byte if 0 */
        rptr += off;
        state->strm.next_in = rptr;
        state->strm.avail_in = (isize - off);

        for (;;) {
                r = deflate(&state->strm, Z_PACKET_FLUSH);
                if (r != Z_OK) {
                        if (state->debug)
                                printk(KERN_ERR
                                       "z_compress: deflate returned %d\n", r);
                        break;
                }
                if (state->strm.avail_out == 0) {
                        olen += oavail;
                        state->strm.next_out = NULL;
                        state->strm.avail_out = oavail = 1000000;
                } else {
                        break;          /* all done */
                }
        }
        olen += oavail - state->strm.avail_out;

        /*
         * See if we managed to reduce the size of the packet.
         */
        if (olen < isize) {
                state->stats.comp_bytes += olen;
                state->stats.comp_packets++;
        } else {
                state->stats.inc_bytes += isize;
                state->stats.inc_packets++;
                olen = 0;
        }
        state->stats.unc_bytes += isize;
        state->stats.unc_packets++;

        return olen;
}

static void
z_comp_stats(arg, stats)
    void *arg;
    struct compstat *stats;
{
        struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

        *stats = state->stats;
}

static void
z_decomp_free(arg)
    void *arg;
{
        struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

        if (state) {
                inflateEnd(&state->strm);
                kfree(state);
                MOD_DEC_USE_COUNT;
        }
}

/*
 * Allocate space for a decompressor.
 */
static void *
z_decomp_alloc(options, opt_len)
    unsigned char *options;
    int opt_len;
{
        struct ppp_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;

        state = (struct ppp_deflate_state *) kmalloc(sizeof(*state), GFP_KERNEL);
        if (state == NULL)
                return NULL;

        MOD_INC_USE_COUNT;
        memset (state, 0, sizeof (struct ppp_deflate_state));
        state->w_size        = w_size;
        state->strm.next_out = NULL;
        state->strm.zalloc   = zalloc_init;
        state->strm.zfree    = zfree;

        if (inflateInit2(&state->strm, -w_size) != Z_OK)
                goto out_free;
        state->strm.zalloc = zalloc;
        return (void *) state;

out_free:
        z_decomp_free(state);
        MOD_DEC_USE_COUNT;
        return NULL;
}

static int
z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
    void *arg;
    unsigned char *options;
    int opt_len, unit, hdrlen, mru, debug;
{
        struct ppp_deflate_state *state = (struct ppp_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->debug = debug;
        state->mru   = mru;

        inflateReset(&state->strm);

        return 1;
}

static void
z_decomp_reset(arg)
    void *arg;
{
        struct ppp_deflate_state *state = (struct ppp_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, ibuf, isize, obuf, osize)
    void *arg;
    unsigned char *ibuf;
    int isize;
    unsigned char *obuf;
    int osize;
{
        struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
        int olen, seq, r;
        int decode_proto, overflow;
        unsigned char overflow_buf[1];

        if (isize <= PPP_HDRLEN + DEFLATE_OVHD) {
                if (state->debug)
                        printk(KERN_DEBUG "z_decompress%d: short pkt (%d)\n",
                               state->unit, isize);
                return DECOMP_ERROR;
        }

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

        /*
         * Fill in the first part of the PPP header.  The protocol field
         * comes from the decompressed data.
         */
        obuf[0] = PPP_ADDRESS(ibuf);
        obuf[1] = PPP_CONTROL(ibuf);
        obuf[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 = ibuf + PPP_HDRLEN + DEFLATE_OVHD;
        state->strm.avail_in = isize - (PPP_HDRLEN + DEFLATE_OVHD);
        state->strm.next_out = obuf + 3;
        state->strm.avail_out = 1;
        decode_proto = 1;
        overflow = 0;

        /*
         * Call inflate, supplying more input or output as needed.
         */
        for (;;) {
                r = inflate(&state->strm, Z_PACKET_FLUSH);
                if (r != Z_OK) {
                        if (state->debug)
                                printk(KERN_DEBUG "z_decompress%d: inflate returned %d (%s)\n",
                                       state->unit, r, (state->strm.msg? state->strm.msg: ""));
                        return DECOMP_FATALERROR;
                }
                if (state->strm.avail_out != 0)
                        break;          /* all done */
                if (decode_proto) {
                        state->strm.avail_out = osize - PPP_HDRLEN;
                        if ((obuf[3] & 1) == 0) {
                                /* 2-byte protocol field */
                                obuf[2] = obuf[3];
                                --state->strm.next_out;
                                ++state->strm.avail_out;
                        }
                        decode_proto = 0;
                } else if (!overflow) {
                        /*
                         * We've filled up the output buffer; the only way to
                         * find out whether inflate has any more characters
                         * left is to give it another byte of output space.
                         */
                        state->strm.next_out = overflow_buf;
                        state->strm.avail_out = 1;
                        overflow = 1;
                } else {
                        if (state->debug)
                                printk(KERN_DEBUG "z_decompress%d: ran out of mru\n",
                                       state->unit);
                        return DECOMP_FATALERROR;
                }
        }

        if (decode_proto) {
                if (state->debug)
                        printk(KERN_DEBUG "z_decompress%d: didn't get proto\n",
                               state->unit);
                return DECOMP_ERROR;
        }

        olen = osize + overflow - state->strm.avail_out;
        state->stats.unc_bytes += olen;
        state->stats.unc_packets++;
        state->stats.comp_bytes += isize;
        state->stats.comp_packets++;

        return olen;
}

/*
 * Incompressible data has arrived - add it to the history.
 */
static void
z_incomp(arg, ibuf, icnt)
    void *arg;
    unsigned char *ibuf;
    int icnt;
{
        struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
        int proto, r;

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

        ++state->seqno;

        /*
         * We start at the either the 1st or 2nd byte of the protocol field,
         * depending on whether the protocol value is compressible.
         */
        state->strm.next_in = ibuf + 3;
        state->strm.avail_in = icnt - 3;
        if (proto > 0xff) {
                --state->strm.next_in;
                ++state->strm.avail_in;
        }

        r = inflateIncomp(&state->strm);
        if (r != Z_OK) {
                /* gak! */
                if (state->debug) {
                        printk(KERN_DEBUG "z_incomp%d: inflateIncomp returned %d (%s)\n",
                               state->unit, r, (state->strm.msg? state->strm.msg: ""));
                }
                return;
        }

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

/*************************************************************
 * Module interface table
 *************************************************************/

/* These are in ppp.c */
extern int  ppp_register_compressor   (struct compressor *cp);
extern void ppp_unregister_compressor (struct compressor *cp);

/*
 * 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 */
};

#ifdef MODULE
/*************************************************************
 * Module support routines
 *************************************************************/

int
init_module(void)
{  
        int answer = ppp_register_compressor (&ppp_deflate);
        if (answer == 0)
                printk (KERN_INFO
                        "PPP Deflate Compression module registered\n");
        ppp_register_compressor(&ppp_deflate_draft);
        return answer;
}
     
void
cleanup_module(void)
{
        if (MOD_IN_USE)
                printk (KERN_INFO
                        "Deflate Compression module busy, remove delayed\n");
        else {
                ppp_unregister_compressor (&ppp_deflate);
                ppp_unregister_compressor (&ppp_deflate_draft);
        }
}
#endif