2 * ppp_deflate.c - interface the zlib procedures for Deflate compression
3 * and decompression (as used by gzip) to the PPP code.
5 * Copyright (c) 1994 The Australian National University.
8 * Permission to use, copy, modify, and distribute this software and its
9 * documentation is hereby granted, provided that the above copyright
10 * notice appears in all copies. This software is provided without any
11 * warranty, express or implied. The Australian National University
12 * makes no representations about the suitability of this software for
15 * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
16 * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
17 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
18 * THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY
21 * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
22 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
23 * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
24 * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
25 * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
28 * $Id: deflate.c,v 1.3 1999/04/16 11:35:59 paulus Exp $
31 #include <sys/types.h>
40 #define DEFLATE_DEBUG 1
43 * State for a Deflate (de)compressor.
45 struct deflate_state {
53 struct compstat stats;
56 #define DEFLATE_OVHD 2 /* Deflate overhead/packet */
58 static void *z_alloc __P((void *, u_int items, u_int size));
59 static void z_free __P((void *, void *ptr, u_int nb));
60 static void *z_decomp_alloc __P((u_char *options, int opt_len));
61 static void z_decomp_free __P((void *state));
62 static int z_decomp_init __P((void *state, u_char *options, int opt_len,
63 int unit, int hdrlen, int mru, int debug));
64 static void z_incomp __P((void *state, u_char *dmsg, int len));
65 static int z_decompress __P((void *state, u_char *cmp, int inlen,
66 u_char *dmp, int *outlenp));
67 static void z_decomp_reset __P((void *state));
68 static void z_comp_stats __P((void *state, struct compstat *stats));
71 * Procedures exported to if_ppp.c.
73 struct compressor ppp_deflate = {
74 CI_DEFLATE, /* compress_proto */
75 z_decomp_alloc, /* decomp_alloc */
76 z_decomp_free, /* decomp_free */
77 z_decomp_init, /* decomp_init */
78 z_decomp_reset, /* decomp_reset */
79 z_decompress, /* decompress */
80 z_incomp, /* incomp */
81 z_comp_stats, /* decomp_stat */
85 * Space allocation and freeing routines for use by zlib routines.
88 z_alloc(notused, items, size)
92 return malloc(items * size);
96 z_free(notused, ptr, nbytes)
105 z_comp_stats(arg, stats)
107 struct compstat *stats;
109 struct deflate_state *state = (struct deflate_state *) arg;
112 *stats = state->stats;
113 stats->ratio = stats->unc_bytes;
114 out = stats->comp_bytes + stats->unc_bytes;
115 if (stats->ratio <= 0x7ffffff)
124 * Allocate space for a decompressor.
127 z_decomp_alloc(options, opt_len)
131 struct deflate_state *state;
134 if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
135 || options[1] != CILEN_DEFLATE
136 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
137 || options[3] != DEFLATE_CHK_SEQUENCE)
139 w_size = DEFLATE_SIZE(options[2]);
140 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
143 state = (struct deflate_state *) malloc(sizeof(*state));
147 state->strm.next_out = NULL;
148 state->strm.zalloc = (alloc_func) z_alloc;
149 state->strm.zfree = (free_func) z_free;
150 if (inflateInit2(&state->strm, -w_size) != Z_OK) {
155 state->w_size = w_size;
156 memset(&state->stats, 0, sizeof(state->stats));
157 return (void *) state;
164 struct deflate_state *state = (struct deflate_state *) arg;
166 inflateEnd(&state->strm);
171 z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
174 int opt_len, unit, hdrlen, mru, debug;
176 struct deflate_state *state = (struct deflate_state *) arg;
178 if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
179 || options[1] != CILEN_DEFLATE
180 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
181 || DEFLATE_SIZE(options[2]) != state->w_size
182 || options[3] != DEFLATE_CHK_SEQUENCE)
187 state->hdrlen = hdrlen;
188 state->debug = debug;
191 inflateReset(&state->strm);
200 struct deflate_state *state = (struct deflate_state *) arg;
203 inflateReset(&state->strm);
207 * Decompress a Deflate-compressed packet.
209 * Because of patent problems, we return DECOMP_ERROR for errors
210 * found by inspecting the input data and for system problems, but
211 * DECOMP_FATALERROR for any errors which could possibly be said to
212 * be being detected "after" decompression. For DECOMP_ERROR,
213 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
214 * infringing a patent of Motorola's if we do, so we take CCP down
217 * Given that the frame has the correct sequence number and a good FCS,
218 * errors such as invalid codes in the input most likely indicate a
219 * bug, so we return DECOMP_FATALERROR for them in order to turn off
220 * compression, even though they are detected by inspecting the input.
223 z_decompress(arg, mi, inlen, mo, outlenp)
228 struct deflate_state *state = (struct deflate_state *) arg;
230 int rlen, olen, ospace;
231 int seq, i, flush, r, decode_proto;
238 /* Check the sequence number. */
239 seq = (rptr[0] << 8) + rptr[1];
241 if (seq != state->seqno) {
245 printf("z_decompress%d: bad seq # %d, expected %d\n",
246 state->unit, seq, state->seqno);
252 * Set up to call inflate.
255 state->strm.next_in = rptr;
256 state->strm.avail_in = mi + inlen - rptr;
257 rlen = state->strm.avail_in + PPP_HDRLEN + DEFLATE_OVHD;
258 state->strm.next_out = wptr;
259 state->strm.avail_out = state->mru + 2;
261 r = inflate(&state->strm, Z_PACKET_FLUSH);
266 printf("z_decompress%d: inflate returned %d (%s)\n",
267 state->unit, r, (state->strm.msg? state->strm.msg: ""));
268 return DECOMP_FATALERROR;
270 olen = state->mru + 2 - state->strm.avail_out;
273 if ((wptr[0] & 1) != 0)
274 ++olen; /* for suppressed protocol high byte */
275 olen += 2; /* for address, control */
278 if (olen > state->mru + PPP_HDRLEN)
279 printf("ppp_deflate%d: exceeded mru (%d > %d)\n",
280 state->unit, olen, state->mru + PPP_HDRLEN);
283 state->stats.unc_bytes += olen;
284 state->stats.unc_packets++;
285 state->stats.comp_bytes += rlen;
286 state->stats.comp_packets++;
292 * Incompressible data has arrived - add it to the history.
295 z_incomp(arg, mi, mlen)
300 struct deflate_state *state = (struct deflate_state *) arg;
305 * Check that the protocol is one we handle.
309 if ((proto & 1) == 0)
310 proto = (proto << 8) + rptr[1];
311 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
318 rlen = mi + mlen - rptr;
319 state->strm.next_in = rptr;
320 state->strm.avail_in = rlen;
321 r = inflateIncomp(&state->strm);
327 printf("z_incomp%d: inflateIncomp returned %d (%s)\n",
328 state->unit, r, (state->strm.msg? state->strm.msg: ""));
338 state->stats.inc_bytes += rlen;
339 state->stats.inc_packets++;
340 state->stats.unc_bytes += rlen;
341 state->stats.unc_packets++;
344 #endif /* DO_DEFLATE */