1/*
2 * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. Please obtain a copy of the License at
10 * http://www.opensource.apple.com/apsl/ and read it before using this
11 * file.
12 *
13 * The Original Code and all software distributed under the License are
14 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
15 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
16 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
18 * Please see the License for the specific language governing rights and
19 * limitations under the License.
20 *
21 * @APPLE_LICENSE_HEADER_END@
22 */
23/*
24 * ppp_deflate.c - interface the zlib procedures for Deflate compression
25 * and decompression (as used by gzip) to the PPP code.
26 *
27 * Copyright (c) 1994 The Australian National University.
28 * All rights reserved.
29 *
30 * Permission to use, copy, modify, and distribute this software and its
31 * documentation is hereby granted, provided that the above copyright
32 * notice appears in all copies.  This software is provided without any
33 * warranty, express or implied. The Australian National University
34 * makes no representations about the suitability of this software for
35 * any purpose.
36 *
37 * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
38 * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
39 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
40 * THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY
41 * OF SUCH DAMAGE.
42 *
43 * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
44 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
45 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
46 * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
47 * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
48 * OR MODIFICATIONS.
49 *
50 * $Id: deflate.c,v 1.3 2003/08/14 00:00:39 callie Exp $
51 */
52
53#include <sys/types.h>
54#include <stddef.h>
55#include <stdlib.h>
56#include "ppp_defs.h"
57#include "ppp-comp.h"
58#include "zlib.h"
59
60#if DO_DEFLATE
61
62#define DEFLATE_DEBUG	1
63
64/*
65 * State for a Deflate (de)compressor.
66 */
67struct deflate_state {
68    int		seqno;
69    int		w_size;
70    int		unit;
71    int		hdrlen;
72    int		mru;
73    int		debug;
74    z_stream	strm;
75    struct compstat stats;
76};
77
78#define DEFLATE_OVHD	2		/* Deflate overhead/packet */
79
80static void	*z_alloc __P((void *, u_int items, u_int size));
81static void	z_free __P((void *, void *ptr, u_int nb));
82static void	*z_decomp_alloc __P((u_char *options, int opt_len));
83static void	z_decomp_free __P((void *state));
84static int	z_decomp_init __P((void *state, u_char *options, int opt_len,
85				     int unit, int hdrlen, int mru, int debug));
86static void	z_incomp __P((void *state, u_char *dmsg, int len));
87static int	z_decompress __P((void *state, u_char *cmp, int inlen,
88				    u_char *dmp, int *outlenp));
89static void	z_decomp_reset __P((void *state));
90static void	z_comp_stats __P((void *state, struct compstat *stats));
91
92/*
93 * Procedures exported to if_ppp.c.
94 */
95struct compressor ppp_deflate = {
96    CI_DEFLATE,			/* compress_proto */
97    z_decomp_alloc,		/* decomp_alloc */
98    z_decomp_free,		/* decomp_free */
99    z_decomp_init,		/* decomp_init */
100    z_decomp_reset,		/* decomp_reset */
101    z_decompress,		/* decompress */
102    z_incomp,			/* incomp */
103    z_comp_stats,		/* decomp_stat */
104};
105
106/*
107 * Space allocation and freeing routines for use by zlib routines.
108 */
109static void *
110z_alloc(notused, items, size)
111    void *notused;
112    u_int items, size;
113{
114    return malloc(items * size);
115}
116
117static void
118z_free(notused, ptr, nbytes)
119    void *notused;
120    void *ptr;
121    u_int nbytes;
122{
123    free(ptr);
124}
125
126static void
127z_comp_stats(arg, stats)
128    void *arg;
129    struct compstat *stats;
130{
131    struct deflate_state *state = (struct deflate_state *) arg;
132    u_int out;
133
134    *stats = state->stats;
135    stats->ratio = stats->unc_bytes;
136    out = stats->comp_bytes + stats->unc_bytes;
137    if (stats->ratio <= 0x7ffffff)
138	stats->ratio <<= 8;
139    else
140	out >>= 8;
141    if (out != 0)
142	stats->ratio /= out;
143}
144
145/*
146 * Allocate space for a decompressor.
147 */
148static void *
149z_decomp_alloc(options, opt_len)
150    u_char *options;
151    int opt_len;
152{
153    struct deflate_state *state;
154    int w_size;
155
156    if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
157	|| options[1] != CILEN_DEFLATE
158	|| DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
159	|| options[3] != DEFLATE_CHK_SEQUENCE)
160	return NULL;
161    w_size = DEFLATE_SIZE(options[2]);
162    if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
163	return NULL;
164
165    state = (struct deflate_state *) malloc(sizeof(*state));
166    if (state == NULL)
167	return NULL;
168
169    state->strm.next_out = NULL;
170    state->strm.zalloc = (alloc_func) z_alloc;
171    state->strm.zfree = (free_func) z_free;
172    if (inflateInit2(&state->strm, -w_size) != Z_OK) {
173	free(state);
174	return NULL;
175    }
176
177    state->w_size = w_size;
178    memset(&state->stats, 0, sizeof(state->stats));
179    return (void *) state;
180}
181
182static void
183z_decomp_free(arg)
184    void *arg;
185{
186    struct deflate_state *state = (struct deflate_state *) arg;
187
188    inflateEnd(&state->strm);
189    free(state);
190}
191
192static int
193z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
194    void *arg;
195    u_char *options;
196    int opt_len, unit, hdrlen, mru, debug;
197{
198    struct deflate_state *state = (struct deflate_state *) arg;
199
200    if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
201	|| options[1] != CILEN_DEFLATE
202	|| DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
203	|| DEFLATE_SIZE(options[2]) != state->w_size
204	|| options[3] != DEFLATE_CHK_SEQUENCE)
205	return 0;
206
207    state->seqno = 0;
208    state->unit = unit;
209    state->hdrlen = hdrlen;
210    state->debug = debug;
211    state->mru = mru;
212
213    inflateReset(&state->strm);
214
215    return 1;
216}
217
218static void
219z_decomp_reset(arg)
220    void *arg;
221{
222    struct deflate_state *state = (struct deflate_state *) arg;
223
224    state->seqno = 0;
225    inflateReset(&state->strm);
226}
227
228/*
229 * Decompress a Deflate-compressed packet.
230 *
231 * Because of patent problems, we return DECOMP_ERROR for errors
232 * found by inspecting the input data and for system problems, but
233 * DECOMP_FATALERROR for any errors which could possibly be said to
234 * be being detected "after" decompression.  For DECOMP_ERROR,
235 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
236 * infringing a patent of Motorola's if we do, so we take CCP down
237 * instead.
238 *
239 * Given that the frame has the correct sequence number and a good FCS,
240 * errors such as invalid codes in the input most likely indicate a
241 * bug, so we return DECOMP_FATALERROR for them in order to turn off
242 * compression, even though they are detected by inspecting the input.
243 */
244static int
245z_decompress(arg, mi, inlen, mo, outlenp)
246    void *arg;
247    u_char *mi, *mo;
248    int inlen, *outlenp;
249{
250    struct deflate_state *state = (struct deflate_state *) arg;
251    u_char *rptr, *wptr;
252    int rlen, olen, ospace;
253    int seq, i, flush, r, decode_proto;
254
255    rptr = mi;
256    if (*rptr == 0)
257	++rptr;
258    ++rptr;
259
260    /* Check the sequence number. */
261    seq = (rptr[0] << 8) + rptr[1];
262    rptr += 2;
263    if (seq != state->seqno) {
264#if !DEFLATE_DEBUG
265	if (state->debug)
266#endif
267	    printf("z_decompress%d: bad seq # %d, expected %d\n",
268		   state->unit, seq, state->seqno);
269	return DECOMP_ERROR;
270    }
271    ++state->seqno;
272
273    /*
274     * Set up to call inflate.
275     */
276    wptr = mo;
277    state->strm.next_in = rptr;
278    state->strm.avail_in = mi + inlen - rptr;
279    rlen = state->strm.avail_in + PPP_HDRLEN + DEFLATE_OVHD;
280    state->strm.next_out = wptr;
281    state->strm.avail_out = state->mru + 2;
282
283    r = inflate(&state->strm, Z_PACKET_FLUSH);
284    if (r != Z_OK) {
285#if !DEFLATE_DEBUG
286	if (state->debug)
287#endif
288	    printf("z_decompress%d: inflate returned %d (%s)\n",
289		   state->unit, r, (state->strm.msg? state->strm.msg: ""));
290	return DECOMP_FATALERROR;
291    }
292    olen = state->mru + 2 - state->strm.avail_out;
293    *outlenp = olen;
294
295    if ((wptr[0] & 1) != 0)
296	++olen;			/* for suppressed protocol high byte */
297    olen += 2;			/* for address, control */
298
299#if DEFLATE_DEBUG
300    if (olen > state->mru + PPP_HDRLEN)
301	printf("ppp_deflate%d: exceeded mru (%d > %d)\n",
302	       state->unit, olen, state->mru + PPP_HDRLEN);
303#endif
304
305    state->stats.unc_bytes += olen;
306    state->stats.unc_packets++;
307    state->stats.comp_bytes += rlen;
308    state->stats.comp_packets++;
309
310    return DECOMP_OK;
311}
312
313/*
314 * Incompressible data has arrived - add it to the history.
315 */
316static void
317z_incomp(arg, mi, mlen)
318    void *arg;
319    u_char *mi;
320    int mlen;
321{
322    struct deflate_state *state = (struct deflate_state *) arg;
323    u_char *rptr;
324    int rlen, proto, r;
325
326    /*
327     * Check that the protocol is one we handle.
328     */
329    rptr = mi;
330    proto = rptr[0];
331    if ((proto & 1) == 0)
332	proto = (proto << 8) + rptr[1];
333    if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
334	return;
335
336    ++state->seqno;
337
338    if (rptr[0] == 0)
339	++rptr;
340    rlen = mi + mlen - rptr;
341    state->strm.next_in = rptr;
342    state->strm.avail_in = rlen;
343    r = inflateIncomp(&state->strm);
344    if (r != Z_OK) {
345	/* gak! */
346#if !DEFLATE_DEBUG
347	if (state->debug)
348#endif
349	    printf("z_incomp%d: inflateIncomp returned %d (%s)\n",
350		   state->unit, r, (state->strm.msg? state->strm.msg: ""));
351	return;
352    }
353
354    /*
355     * Update stats.
356     */
357    if (proto <= 0xff)
358	++rlen;
359    rlen += 2;
360    state->stats.inc_bytes += rlen;
361    state->stats.inc_packets++;
362    state->stats.unc_bytes += rlen;
363    state->stats.unc_packets++;
364}
365
366#endif /* DO_DEFLATE */
367