release/src/router/pppd/pppdump/deflate.c

   1 /*
   2  * ppp_deflate.c - interface the zlib procedures for Deflate compression
   3  * and decompression (as used by gzip) to the PPP code.
   4  *
   5  * Copyright (c) 1994 Paul Mackerras. All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  *
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  *
  19  * 3. The name(s) of the authors of this software must not be used to
  20  *    endorse or promote products derived from this software without
  21  *    prior written permission.
  22  *
  23  * 4. Redistributions of any form whatsoever must retain the following
  24  *    acknowledgment:
  25  *    "This product includes software developed by Paul Mackerras
  26  *     <paulus@samba.org>".
  27  *
  28  * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
  29  * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  30  * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
  31  * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  32  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
  33  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
  34  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  35  *
  36  * $Id: deflate.c,v 1.5 2004/01/17 05:47:55 carlsonj Exp $
  37  */
  38
  39 #include <sys/types.h>
  40 #include <stdio.h>
  41 #include <stddef.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include "ppp_defs.h"
  45 #include "ppp-comp.h"
  46 #include "zlib.h"
  47
  48 #if DO_DEFLATE
  49
  50 #define DEFLATE_DEBUG   1
  51
  52 /*
  53  * State for a Deflate (de)compressor.
  54  */
  55 struct deflate_state {
  56     int         seqno;
  57     int         w_size;
  58     int         unit;
  59     int         hdrlen;
  60     int         mru;
  61     int         debug;
  62     z_stream    strm;
  63     struct compstat stats;
  64 };
  65
  66 #define DEFLATE_OVHD    2               /* Deflate overhead/packet */
  67
  68 static void     *z_alloc __P((void *, u_int items, u_int size));
  69 static void     z_free __P((void *, void *ptr, u_int nb));
  70 static void     *z_decomp_alloc __P((u_char *options, int opt_len));
  71 static void     z_decomp_free __P((void *state));
  72 static int      z_decomp_init __P((void *state, u_char *options, int opt_len,
  73                                      int unit, int hdrlen, int mru, int debug));
  74 static void     z_incomp __P((void *state, u_char *dmsg, int len));
  75 static int      z_decompress __P((void *state, u_char *cmp, int inlen,
  76                                     u_char *dmp, int *outlenp));
  77 static void     z_decomp_reset __P((void *state));
  78 static void     z_comp_stats __P((void *state, struct compstat *stats));
  79
  80 /*
  81  * Procedures exported to if_ppp.c.
  82  */
  83 struct compressor ppp_deflate = {
  84     CI_DEFLATE,                 /* compress_proto */
  85     z_decomp_alloc,             /* decomp_alloc */
  86     z_decomp_free,              /* decomp_free */
  87     z_decomp_init,              /* decomp_init */
  88     z_decomp_reset,             /* decomp_reset */
  89     z_decompress,               /* decompress */
  90     z_incomp,                   /* incomp */
  91     z_comp_stats,               /* decomp_stat */
  92 };
  93
  94 /*
  95  * Space allocation and freeing routines for use by zlib routines.
  96  */
  97 static void *
  98 z_alloc(notused, items, size)
  99     void *notused;
 100     u_int items, size;
 101 {
 102     return malloc(items * size);
 103 }
 104
 105 static void
 106 z_free(notused, ptr, nbytes)
 107     void *notused;
 108     void *ptr;
 109     u_int nbytes;
 110 {
 111     free(ptr);
 112 }
 113
 114 static void
 115 z_comp_stats(arg, stats)
 116     void *arg;
 117     struct compstat *stats;
 118 {
 119     struct deflate_state *state = (struct deflate_state *) arg;
 120     u_int out;
 121
 122     *stats = state->stats;
 123     stats->ratio = stats->unc_bytes;
 124     out = stats->comp_bytes + stats->unc_bytes;
 125     if (stats->ratio <= 0x7ffffff)
 126         stats->ratio <<= 8;
 127     else
 128         out >>= 8;
 129     if (out != 0)
 130         stats->ratio /= out;
 131 }
 132
 133 /*
 134  * Allocate space for a decompressor.
 135  */
 136 static void *
 137 z_decomp_alloc(options, opt_len)
 138     u_char *options;
 139     int opt_len;
 140 {
 141     struct deflate_state *state;
 142     int w_size;
 143
 144     if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
 145         || options[1] != CILEN_DEFLATE
 146         || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
 147         || options[3] != DEFLATE_CHK_SEQUENCE)
 148         return NULL;
 149     w_size = DEFLATE_SIZE(options[2]);
 150     if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
 151         return NULL;
 152
 153     state = (struct deflate_state *) malloc(sizeof(*state));
 154     if (state == NULL)
 155         return NULL;
 156
 157     state->strm.next_out = NULL;
 158     state->strm.zalloc = (alloc_func) z_alloc;
 159     state->strm.zfree = (free_func) z_free;
 160     if (inflateInit2(&state->strm, -w_size) != Z_OK) {
 161         free(state);
 162         return NULL;
 163     }
 164
 165     state->w_size = w_size;
 166     memset(&state->stats, 0, sizeof(state->stats));
 167     return (void *) state;
 168 }
 169
 170 static void
 171 z_decomp_free(arg)
 172     void *arg;
 173 {
 174     struct deflate_state *state = (struct deflate_state *) arg;
 175
 176     inflateEnd(&state->strm);
 177     free(state);
 178 }
 179
 180 static int
 181 z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
 182     void *arg;
 183     u_char *options;
 184     int opt_len, unit, hdrlen, mru, debug;
 185 {
 186     struct deflate_state *state = (struct deflate_state *) arg;
 187
 188     if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
 189         || options[1] != CILEN_DEFLATE
 190         || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
 191         || DEFLATE_SIZE(options[2]) != state->w_size
 192         || options[3] != DEFLATE_CHK_SEQUENCE)
 193         return 0;
 194
 195     state->seqno = 0;
 196     state->unit = unit;
 197     state->hdrlen = hdrlen;
 198     state->debug = debug;
 199     state->mru = mru;
 200
 201     inflateReset(&state->strm);
 202
 203     return 1;
 204 }
 205
 206 static void
 207 z_decomp_reset(arg)
 208     void *arg;
 209 {
 210     struct deflate_state *state = (struct deflate_state *) arg;
 211
 212     state->seqno = 0;
 213     inflateReset(&state->strm);
 214 }
 215
 216 /*
 217  * Decompress a Deflate-compressed packet.
 218  *
 219  * Because of patent problems, we return DECOMP_ERROR for errors
 220  * found by inspecting the input data and for system problems, but
 221  * DECOMP_FATALERROR for any errors which could possibly be said to
 222  * be being detected "after" decompression.  For DECOMP_ERROR,
 223  * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
 224  * infringing a patent of Motorola's if we do, so we take CCP down
 225  * instead.
 226  *
 227  * Given that the frame has the correct sequence number and a good FCS,
 228  * errors such as invalid codes in the input most likely indicate a
 229  * bug, so we return DECOMP_FATALERROR for them in order to turn off
 230  * compression, even though they are detected by inspecting the input.
 231  */
 232 static int
 233 z_decompress(arg, mi, inlen, mo, outlenp)
 234     void *arg;
 235     u_char *mi, *mo;
 236     int inlen, *outlenp;
 237 {
 238     struct deflate_state *state = (struct deflate_state *) arg;
 239     u_char *rptr, *wptr;
 240     int rlen, olen;
 241     int seq, r;
 242
 243     rptr = mi;
 244     if (*rptr == 0)
 245         ++rptr;
 246     ++rptr;
 247
 248     /* Check the sequence number. */
 249     seq = (rptr[0] << 8) + rptr[1];
 250     rptr += 2;
 251     if (seq != state->seqno) {
 252 #if !DEFLATE_DEBUG
 253         if (state->debug)
 254 #endif
 255             printf("z_decompress%d: bad seq # %d, expected %d\n",
 256                    state->unit, seq, state->seqno);
 257         return DECOMP_ERROR;
 258     }
 259     ++state->seqno;
 260
 261     /*
 262      * Set up to call inflate.
 263      */
 264     wptr = mo;
 265     state->strm.next_in = rptr;
 266     state->strm.avail_in = mi + inlen - rptr;
 267     rlen = state->strm.avail_in + PPP_HDRLEN + DEFLATE_OVHD;
 268     state->strm.next_out = wptr;
 269     state->strm.avail_out = state->mru + 2;
 270
 271     r = inflate(&state->strm, Z_PACKET_FLUSH);
 272     if (r != Z_OK) {
 273 #if !DEFLATE_DEBUG
 274         if (state->debug)
 275 #endif
 276             printf("z_decompress%d: inflate returned %d (%s)\n",
 277                    state->unit, r, (state->strm.msg? state->strm.msg: ""));
 278         return DECOMP_FATALERROR;
 279     }
 280     olen = state->mru + 2 - state->strm.avail_out;
 281     *outlenp = olen;
 282
 283     if ((wptr[0] & 1) != 0)
 284         ++olen;                 /* for suppressed protocol high byte */
 285     olen += 2;                  /* for address, control */
 286
 287 #if DEFLATE_DEBUG
 288     if (olen > state->mru + PPP_HDRLEN)
 289         printf("ppp_deflate%d: exceeded mru (%d > %d)\n",
 290                state->unit, olen, state->mru + PPP_HDRLEN);
 291 #endif
 292
 293     state->stats.unc_bytes += olen;
 294     state->stats.unc_packets++;
 295     state->stats.comp_bytes += rlen;
 296     state->stats.comp_packets++;
 297
 298     return DECOMP_OK;
 299 }
 300
 301 /*
 302  * Incompressible data has arrived - add it to the history.
 303  */
 304 static void
 305 z_incomp(arg, mi, mlen)
 306     void *arg;
 307     u_char *mi;
 308     int mlen;
 309 {
 310     struct deflate_state *state = (struct deflate_state *) arg;
 311     u_char *rptr;
 312     int rlen, proto, r;
 313
 314     /*
 315      * Check that the protocol is one we handle.
 316      */
 317     rptr = mi;
 318     proto = rptr[0];
 319     if ((proto & 1) == 0)
 320         proto = (proto << 8) + rptr[1];
 321     if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
 322         return;
 323
 324     ++state->seqno;
 325
 326     if (rptr[0] == 0)
 327         ++rptr;
 328     rlen = mi + mlen - rptr;
 329     state->strm.next_in = rptr;
 330     state->strm.avail_in = rlen;
 331     r = inflateIncomp(&state->strm);
 332     if (r != Z_OK) {
 333         /* gak! */
 334 #if !DEFLATE_DEBUG
 335         if (state->debug)
 336 #endif
 337             printf("z_incomp%d: inflateIncomp returned %d (%s)\n",
 338                    state->unit, r, (state->strm.msg? state->strm.msg: ""));
 339         return;
 340     }
 341
 342     /*
 343      * Update stats.
 344      */
 345     if (proto <= 0xff)
 346         ++rlen;
 347     rlen += 2;
 348     state->stats.inc_bytes += rlen;
 349     state->stats.inc_packets++;
 350     state->stats.unc_bytes += rlen;
 351     state->stats.unc_packets++;
 352 }
 353
 354 #endif /* DO_DEFLATE */