Subversion Repositories test_project

/*

 *  ==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/slab.h>

#include <linux/vmalloc.h>

#include <linux/init.h>

#include <linux/string.h>

#include <linux/ppp_defs.h>

#include <linux/ppp-comp.h>

#include <linux/zlib.h>

/*

 * 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     *z_comp_alloc(unsigned char *options, int opt_len);

static void     *z_decomp_alloc(unsigned 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, unsigned char *options,

                                 int opt_len,

                                 int unit, int hdrlen, int debug);

static int      z_decomp_init(void *state, unsigned char *options,

                                   int opt_len,

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

static int      z_compress(void *state, unsigned char *rptr,

                                unsigned char *obuf,

                                int isize, int osize);

static void     z_incomp(void *state, unsigned char *ibuf, int icnt);

static int      z_decompress(void *state, unsigned char *ibuf,

                                int isize, unsigned char *obuf, int osize);

static void     z_comp_reset(void *state);

static void     z_decomp_reset(void *state);

static void     z_comp_stats(void *state, struct compstat *stats);

/**

 *      z_comp_free - free the memory used by a compressor

 *      @arg:   pointer to the private state for the compressor.

 */

static void z_comp_free(void *arg)

{

        struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

        if (state) {

                zlib_deflateEnd(&state->strm);

                vfree(state->strm.workspace);

                kfree(state);

        }

}

/**

 *      z_comp_alloc - allocate space for a compressor.

 *      @options: pointer to CCP option data

 *      @opt_len: length of the CCP option at @options.

 *

 *      The @options pointer points to the a buffer containing the

 *      CCP option data for the compression being negotiated.  It is

 *      formatted according to RFC1979, and describes the window

 *      size that the peer is requesting that we use in compressing

 *      data to be sent to it.

 *

 *      Returns the pointer to the private state for the compressor,

 *      or NULL if we could not allocate enough memory.

 */

static void *z_comp_alloc(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 = kzalloc(sizeof(*state),

                                                     GFP_KERNEL);

        if (state == NULL)

                return NULL;

        state->strm.next_in   = NULL;

        state->w_size         = w_size;

        state->strm.workspace = vmalloc(zlib_deflate_workspacesize());

        if (state->strm.workspace == NULL)

                goto out_free;

        if (zlib_deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION,

                         DEFLATE_METHOD_VAL, -w_size, 8, Z_DEFAULT_STRATEGY)

            != Z_OK)

                goto out_free;

        return (void *) state;

out_free:

        z_comp_free(state);

        return NULL;

}

/**

 *      z_comp_init - initialize a previously-allocated compressor.

 *      @arg:   pointer to the private state for the compressor

 *      @options: pointer to the CCP option data describing the

 *              compression that was negotiated with the peer

 *      @opt_len: length of the CCP option data at @options

 *      @unit:  PPP unit number for diagnostic messages

 *      @hdrlen: ignored (present for backwards compatibility)

 *      @debug: debug flag; if non-zero, debug messages are printed.

 *

 *      The CCP options described by @options must match the options

 *      specified when the compressor was allocated.  The compressor

 *      history is reset.  Returns 0 for failure (CCP options don't

 *      match) or 1 for success.

 */

static int z_comp_init(void *arg, unsigned char *options, int opt_len,

                       int unit, int hdrlen, int 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;

        zlib_deflateReset(&state->strm);

        return 1;

}

/**

 *      z_comp_reset - reset a previously-allocated compressor.

 *      @arg:   pointer to private state for the compressor.

 *

 *      This clears the history for the compressor and makes it

 *      ready to start emitting a new compressed stream.

 */

static void z_comp_reset(void *arg)

{

        struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

        state->seqno = 0;

        zlib_deflateReset(&state->strm);

}

/**

 *      z_compress - compress a PPP packet with Deflate compression.

 *      @arg:   pointer to private state for the compressor

 *      @rptr:  uncompressed packet (input)

 *      @obuf:  compressed packet (output)

 *      @isize: size of uncompressed packet

 *      @osize: space available at @obuf

 *

 *      Returns the length of the compressed packet, or 0 if the

 *      packet is incompressible.

 */

int z_compress(void *arg, unsigned char *rptr, unsigned char *obuf,

               int isize, int 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 = zlib_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;

}

/**

 *      z_comp_stats - return compression statistics for a compressor

 *              or decompressor.

 *      @arg:   pointer to private space for the (de)compressor

 *      @stats: pointer to a struct compstat to receive the result.

 */

static void z_comp_stats(void *arg, struct compstat *stats)

{

        struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

        *stats = state->stats;

}

/**

 *      z_decomp_free - Free the memory used by a decompressor.

 *      @arg:   pointer to private space for the decompressor.

 */

static void z_decomp_free(void *arg)

{

        struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

        if (state) {

                zlib_inflateEnd(&state->strm);

                kfree(state->strm.workspace);

                kfree(state);

        }

}

/**

 *      z_decomp_alloc - allocate space for a decompressor.

 *      @options: pointer to CCP option data

 *      @opt_len: length of the CCP option at @options.

 *

 *      The @options pointer points to the a buffer containing the

 *      CCP option data for the compression being negotiated.  It is

 *      formatted according to RFC1979, and describes the window

 *      size that we are requesting the peer to use in compressing

 *      data to be sent to us.

 *

 *      Returns the pointer to the private state for the decompressor,

 *      or NULL if we could not allocate enough memory.

 */

static void *z_decomp_alloc(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 = kzalloc(sizeof(*state), GFP_KERNEL);

        if (state == NULL)

                return NULL;

        state->w_size         = w_size;

        state->strm.next_out  = NULL;

        state->strm.workspace = kmalloc(zlib_inflate_workspacesize(),

                                        GFP_KERNEL|__GFP_REPEAT);

        if (state->strm.workspace == NULL)

                goto out_free;

        if (zlib_inflateInit2(&state->strm, -w_size) != Z_OK)

                goto out_free;

        return (void *) state;

out_free:

        z_decomp_free(state);

        return NULL;

}

/**

 *      z_decomp_init - initialize a previously-allocated decompressor.

 *      @arg:   pointer to the private state for the decompressor

 *      @options: pointer to the CCP option data describing the

 *              compression that was negotiated with the peer

 *      @opt_len: length of the CCP option data at @options

 *      @unit:  PPP unit number for diagnostic messages

 *      @hdrlen: ignored (present for backwards compatibility)

 *      @mru:   maximum length of decompressed packets

 *      @debug: debug flag; if non-zero, debug messages are printed.

 *

 *      The CCP options described by @options must match the options

 *      specified when the decompressor was allocated.  The decompressor

 *      history is reset.  Returns 0 for failure (CCP options don't

 *      match) or 1 for success.

 */

static int z_decomp_init(void *arg, unsigned char *options, int opt_len,

                         int unit, int hdrlen, int mru, int 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;

        zlib_inflateReset(&state->strm);

        return 1;

}

/**

 *      z_decomp_reset - reset a previously-allocated decompressor.

 *      @arg:   pointer to private state for the decompressor.

 *

 *      This clears the history for the decompressor and makes it

 *      ready to receive a new compressed stream.

 */

static void z_decomp_reset(void *arg)

{

        struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;

        state->seqno = 0;

        zlib_inflateReset(&state->strm);

}

/**

 *      z_decompress - decompress a Deflate-compressed packet.

 *      @arg:   pointer to private state for the decompressor

 *      @ibuf:  pointer to input (compressed) packet data

 *      @isize: length of input packet

 *      @obuf:  pointer to space for output (decompressed) packet

 *      @osize: amount of space available at @obuf

 *

 * 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(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 & 0xffff)) {

                if (state->debug)

                        printk(KERN_DEBUG "z_decompress%d: bad seq # %d, expected %d\n",

                               state->unit, seq, state->seqno & 0xffff);

                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 = zlib_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;

}

/**

 *      z_incomp - add incompressible input data to the history.

 *      @arg:   pointer to private state for the decompressor

 *      @ibuf:  pointer to input packet data

 *      @icnt:  length of input data.

 */

static void z_incomp(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 = zlib_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_generic.c */

extern int  ppp_register_compressor   (struct compressor *cp);

extern void ppp_unregister_compressor (struct compressor *cp);

/*

 * Procedures exported to if_ppp.c.

 */

static struct compressor ppp_deflate = {

        .compress_proto =       CI_DEFLATE,

        .comp_alloc =           z_comp_alloc,

        .comp_free =            z_comp_free,

        .comp_init =            z_comp_init,

        .comp_reset =           z_comp_reset,

        .compress =             z_compress,

        .comp_stat =            z_comp_stats,

        .decomp_alloc =         z_decomp_alloc,

        .decomp_free =          z_decomp_free,

        .decomp_init =          z_decomp_init,

        .decomp_reset =         z_decomp_reset,

        .decompress =           z_decompress,

        .incomp =               z_incomp,

        .decomp_stat =          z_comp_stats,

        .owner =                THIS_MODULE

};

static struct compressor ppp_deflate_draft = {

        .compress_proto =       CI_DEFLATE_DRAFT,

        .comp_alloc =           z_comp_alloc,

        .comp_free =            z_comp_free,

        .comp_init =            z_comp_init,

        .comp_reset =           z_comp_reset,

        .compress =             z_compress,

        .comp_stat =            z_comp_stats,

        .decomp_alloc =         z_decomp_alloc,

        .decomp_free =          z_decomp_free,

        .decomp_init =          z_decomp_init,

        .decomp_reset =         z_decomp_reset,

        .decompress =           z_decompress,

        .incomp =               z_incomp,

        .decomp_stat =          z_comp_stats,

        .owner =                THIS_MODULE

};

static int __init deflate_init(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;

}

static void __exit deflate_cleanup(void)

{

        ppp_unregister_compressor(&ppp_deflate);

        ppp_unregister_compressor(&ppp_deflate_draft);

}

module_init(deflate_init);

module_exit(deflate_cleanup);

MODULE_LICENSE("Dual BSD/GPL");

MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE));

MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE_DRAFT));