1 /* $Id: ppp-deflate.c,v 1.7 1997/11/27 06:06:31 paulus Exp $ */
4 * ppp_deflate.c - interface the zlib procedures for Deflate compression
5 * and decompression (as used by gzip) to the PPP code.
6 * This version is for use with mbufs on BSD-derived systems.
8 * Copyright (c) 1994 The Australian National University.
11 * Permission to use, copy, modify, and distribute this software and its
12 * documentation is hereby granted, provided that the above copyright
13 * notice appears in all copies. This software is provided without any
14 * warranty, express or implied. The Australian National University
15 * makes no representations about the suitability of this software for
18 * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
19 * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
20 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
21 * THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY
24 * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
25 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
26 * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
27 * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
28 * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
32 #include <sys/param.h>
33 #include <sys/types.h>
34 #include <sys/systm.h>
36 #include <net/ppp_defs.h>
39 #define PACKETPTR struct mbuf *
40 #include <net/ppp-comp.h>
44 #define DEFLATE_DEBUG 1
47 * State for a Deflate (de)compressor.
49 struct deflate_state {
57 struct compstat stats;
60 #define DEFLATE_OVHD 2 /* Deflate overhead/packet */
62 static void *zalloc __P((void *, u_int items, u_int size));
63 static void zfree __P((void *, void *ptr));
64 static void *z_comp_alloc __P((u_char *options, int opt_len));
65 static void *z_decomp_alloc __P((u_char *options, int opt_len));
66 static void z_comp_free __P((void *state));
67 static void z_decomp_free __P((void *state));
68 static int z_comp_init __P((void *state, u_char *options, int opt_len,
69 int unit, int hdrlen, int debug));
70 static int z_decomp_init __P((void *state, u_char *options, int opt_len,
71 int unit, int hdrlen, int mru, int debug));
72 static int z_compress __P((void *state, struct mbuf **mret,
73 struct mbuf *mp, int slen, int maxolen));
74 static void z_incomp __P((void *state, struct mbuf *dmsg));
75 static int z_decompress __P((void *state, struct mbuf *cmp,
77 static void z_comp_reset __P((void *state));
78 static void z_decomp_reset __P((void *state));
79 static void z_comp_stats __P((void *state, struct compstat *stats));
82 * Procedures exported to if_ppp.c.
84 struct compressor ppp_deflate = {
85 CI_DEFLATE, /* compress_proto */
86 z_comp_alloc, /* comp_alloc */
87 z_comp_free, /* comp_free */
88 z_comp_init, /* comp_init */
89 z_comp_reset, /* comp_reset */
90 z_compress, /* compress */
91 z_comp_stats, /* comp_stat */
92 z_decomp_alloc, /* decomp_alloc */
93 z_decomp_free, /* decomp_free */
94 z_decomp_init, /* decomp_init */
95 z_decomp_reset, /* decomp_reset */
96 z_decompress, /* decompress */
97 z_incomp, /* incomp */
98 z_comp_stats, /* decomp_stat */
102 * Space allocation and freeing routines for use by zlib routines.
105 zalloc(notused, items, size)
111 MALLOC(ptr, void *, items * size, M_DEVBUF, M_NOWAIT);
124 * Allocate space for a compressor.
127 z_comp_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 MALLOC(state, struct deflate_state *, sizeof(struct deflate_state),
148 state->strm.next_in = NULL;
149 state->strm.zalloc = zalloc;
150 state->strm.zfree = zfree;
151 if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION, DEFLATE_METHOD_VAL,
152 -w_size, 8, Z_DEFAULT_STRATEGY) != Z_OK) {
153 FREE(state, M_DEVBUF);
157 state->w_size = w_size;
158 bzero(&state->stats, sizeof(state->stats));
159 return (void *) state;
166 struct deflate_state *state = (struct deflate_state *) arg;
168 deflateEnd(&state->strm);
169 FREE(state, M_DEVBUF);
173 z_comp_init(arg, options, opt_len, unit, hdrlen, debug)
176 int opt_len, unit, hdrlen, debug;
178 struct deflate_state *state = (struct deflate_state *) arg;
180 if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
181 || options[1] != CILEN_DEFLATE
182 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
183 || DEFLATE_SIZE(options[2]) != state->w_size
184 || options[3] != DEFLATE_CHK_SEQUENCE)
189 state->hdrlen = hdrlen;
190 state->debug = debug;
192 deflateReset(&state->strm);
201 struct deflate_state *state = (struct deflate_state *) arg;
204 deflateReset(&state->strm);
208 z_compress(arg, mret, mp, orig_len, maxolen)
210 struct mbuf **mret; /* compressed packet (out) */
211 struct mbuf *mp; /* uncompressed packet (in) */
212 int orig_len, maxolen;
214 struct deflate_state *state = (struct deflate_state *) arg;
216 int proto, olen, wspace, r, flush;
220 * Check that the protocol is in the range we handle.
222 rptr = mtod(mp, u_char *);
223 proto = PPP_PROTOCOL(rptr);
224 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) {
229 /* Allocate one mbuf initially. */
230 if (maxolen > orig_len)
232 MGET(m, M_DONTWAIT, MT_DATA);
236 if (maxolen + state->hdrlen > MLEN)
237 MCLGET(m, M_DONTWAIT);
238 wspace = M_TRAILINGSPACE(m);
239 if (state->hdrlen + PPP_HDRLEN + 2 < wspace) {
240 m->m_data += state->hdrlen;
241 wspace -= state->hdrlen;
243 wptr = mtod(m, u_char *);
246 * Copy over the PPP header and store the 2-byte sequence number.
248 wptr[0] = PPP_ADDRESS(rptr);
249 wptr[1] = PPP_CONTROL(rptr);
250 wptr[2] = PPP_COMP >> 8;
253 wptr[0] = state->seqno >> 8;
254 wptr[1] = state->seqno;
256 state->strm.next_out = wptr;
257 state->strm.avail_out = wspace - (PPP_HDRLEN + 2);
259 state->strm.next_out = NULL;
260 state->strm.avail_out = 1000000;
266 rptr += (proto > 0xff)? 2: 3; /* skip 1st proto byte if 0 */
267 state->strm.next_in = rptr;
268 state->strm.avail_in = mtod(mp, u_char *) + mp->m_len - rptr;
270 flush = (mp == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
273 r = deflate(&state->strm, flush);
275 printf("z_compress: deflate returned %d (%s)\n",
276 r, (state->strm.msg? state->strm.msg: ""));
279 if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
280 break; /* all done */
281 if (state->strm.avail_in == 0 && mp != NULL) {
282 state->strm.next_in = mtod(mp, u_char *);
283 state->strm.avail_in = mp->m_len;
286 flush = Z_PACKET_FLUSH;
288 if (state->strm.avail_out == 0) {
292 MGET(m->m_next, M_DONTWAIT, MT_DATA);
296 if (maxolen - olen > MLEN)
297 MCLGET(m, M_DONTWAIT);
298 state->strm.next_out = mtod(m, u_char *);
299 state->strm.avail_out = wspace = M_TRAILINGSPACE(m);
303 state->strm.next_out = NULL;
304 state->strm.avail_out = 1000000;
309 olen += (m->m_len = wspace - state->strm.avail_out);
312 * See if we managed to reduce the size of the packet.
313 * If the compressor just gave us a single zero byte, it means
314 * the packet was incompressible.
316 if (m != NULL && olen < orig_len
317 && !(olen == PPP_HDRLEN + 3 && *wptr == 0)) {
318 state->stats.comp_bytes += olen;
319 state->stats.comp_packets++;
325 state->stats.inc_bytes += orig_len;
326 state->stats.inc_packets++;
329 state->stats.unc_bytes += orig_len;
330 state->stats.unc_packets++;
336 z_comp_stats(arg, stats)
338 struct compstat *stats;
340 struct deflate_state *state = (struct deflate_state *) arg;
343 *stats = state->stats;
344 stats->ratio = stats->unc_bytes;
345 out = stats->comp_bytes + stats->inc_bytes;
346 if (stats->ratio <= 0x7ffffff)
355 * Allocate space for a decompressor.
358 z_decomp_alloc(options, opt_len)
362 struct deflate_state *state;
365 if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
366 || options[1] != CILEN_DEFLATE
367 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
368 || options[3] != DEFLATE_CHK_SEQUENCE)
370 w_size = DEFLATE_SIZE(options[2]);
371 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
374 MALLOC(state, struct deflate_state *, sizeof(struct deflate_state),
379 state->strm.next_out = NULL;
380 state->strm.zalloc = zalloc;
381 state->strm.zfree = zfree;
382 if (inflateInit2(&state->strm, -w_size) != Z_OK) {
383 FREE(state, M_DEVBUF);
387 state->w_size = w_size;
388 bzero(&state->stats, sizeof(state->stats));
389 return (void *) state;
396 struct deflate_state *state = (struct deflate_state *) arg;
398 inflateEnd(&state->strm);
399 FREE(state, M_DEVBUF);
403 z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
406 int opt_len, unit, hdrlen, mru, debug;
408 struct deflate_state *state = (struct deflate_state *) arg;
410 if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
411 || options[1] != CILEN_DEFLATE
412 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
413 || DEFLATE_SIZE(options[2]) != state->w_size
414 || options[3] != DEFLATE_CHK_SEQUENCE)
419 state->hdrlen = hdrlen;
420 state->debug = debug;
423 inflateReset(&state->strm);
432 struct deflate_state *state = (struct deflate_state *) arg;
435 inflateReset(&state->strm);
439 * Decompress a Deflate-compressed packet.
441 * Because of patent problems, we return DECOMP_ERROR for errors
442 * found by inspecting the input data and for system problems, but
443 * DECOMP_FATALERROR for any errors which could possibly be said to
444 * be being detected "after" decompression. For DECOMP_ERROR,
445 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
446 * infringing a patent of Motorola's if we do, so we take CCP down
449 * Given that the frame has the correct sequence number and a good FCS,
450 * errors such as invalid codes in the input most likely indicate a
451 * bug, so we return DECOMP_FATALERROR for them in order to turn off
452 * compression, even though they are detected by inspecting the input.
455 z_decompress(arg, mi, mop)
457 struct mbuf *mi, **mop;
459 struct deflate_state *state = (struct deflate_state *) arg;
460 struct mbuf *mo, *mo_head;
462 int rlen, olen, ospace;
463 int seq, i, flush, r, decode_proto;
464 u_char hdr[PPP_HDRLEN + DEFLATE_OVHD];
467 rptr = mtod(mi, u_char *);
469 for (i = 0; i < PPP_HDRLEN + DEFLATE_OVHD; ++i) {
474 rptr = mtod(mi, u_char *);
481 /* Check the sequence number. */
482 seq = (hdr[PPP_HDRLEN] << 8) + hdr[PPP_HDRLEN+1];
483 if (seq != state->seqno) {
485 printf("z_decompress%d: bad seq # %d, expected %d\n",
486 state->unit, seq, state->seqno);
491 /* Allocate an output mbuf. */
492 MGETHDR(mo, M_DONTWAIT, MT_DATA);
498 MCLGET(mo, M_DONTWAIT);
499 ospace = M_TRAILINGSPACE(mo);
500 if (state->hdrlen + PPP_HDRLEN < ospace) {
501 mo->m_data += state->hdrlen;
502 ospace -= state->hdrlen;
506 * Fill in the first part of the PPP header. The protocol field
507 * comes from the decompressed data.
509 wptr = mtod(mo, u_char *);
510 wptr[0] = PPP_ADDRESS(hdr);
511 wptr[1] = PPP_CONTROL(hdr);
515 * Set up to call inflate. We set avail_out to 1 initially so we can
516 * look at the first byte of the output and decide whether we have
517 * a 1-byte or 2-byte protocol field.
519 state->strm.next_in = rptr;
520 state->strm.avail_in = rlen;
522 flush = (mi == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
523 rlen += PPP_HDRLEN + DEFLATE_OVHD;
524 state->strm.next_out = wptr + 3;
525 state->strm.avail_out = 1;
530 * Call inflate, supplying more input or output as needed.
533 r = inflate(&state->strm, flush);
538 printf("z_decompress%d: inflate returned %d (%s)\n",
539 state->unit, r, (state->strm.msg? state->strm.msg: ""));
541 return DECOMP_FATALERROR;
543 if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
544 break; /* all done */
545 if (state->strm.avail_in == 0 && mi != NULL) {
546 state->strm.next_in = mtod(mi, u_char *);
547 state->strm.avail_in = mi->m_len;
551 flush = Z_PACKET_FLUSH;
553 if (state->strm.avail_out == 0) {
555 state->strm.avail_out = ospace - PPP_HDRLEN;
556 if ((wptr[3] & 1) == 0) {
557 /* 2-byte protocol field */
559 --state->strm.next_out;
560 ++state->strm.avail_out;
567 MGET(mo->m_next, M_DONTWAIT, MT_DATA);
573 MCLGET(mo, M_DONTWAIT);
574 state->strm.next_out = mtod(mo, u_char *);
575 state->strm.avail_out = ospace = M_TRAILINGSPACE(mo);
583 olen += (mo->m_len = ospace - state->strm.avail_out);
585 if (olen > state->mru + PPP_HDRLEN)
586 printf("ppp_deflate%d: exceeded mru (%d > %d)\n",
587 state->unit, olen, state->mru + PPP_HDRLEN);
590 state->stats.unc_bytes += olen;
591 state->stats.unc_packets++;
592 state->stats.comp_bytes += rlen;
593 state->stats.comp_packets++;
600 * Incompressible data has arrived - add it to the history.
607 struct deflate_state *state = (struct deflate_state *) arg;
612 * Check that the protocol is one we handle.
614 rptr = mtod(mi, u_char *);
615 proto = PPP_PROTOCOL(rptr);
616 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
622 * Iterate through the mbufs, adding the characters in them
623 * to the decompressor's history. For the first mbuf, we start
624 * at the either the 1st or 2nd byte of the protocol field,
625 * depending on whether the protocol value is compressible.
628 state->strm.next_in = rptr + 3;
629 state->strm.avail_in = rlen - 3;
631 --state->strm.next_in;
632 ++state->strm.avail_in;
635 r = inflateIncomp(&state->strm);
641 printf("z_incomp%d: inflateIncomp returned %d (%s)\n",
642 state->unit, r, (state->strm.msg? state->strm.msg: ""));
648 state->strm.next_in = mtod(mi, u_char *);
649 state->strm.avail_in = mi->m_len;
656 state->stats.inc_bytes += rlen;
657 state->stats.inc_packets++;
658 state->stats.unc_bytes += rlen;
659 state->stats.unc_packets++;
662 #endif /* DO_DEFLATE */