1 /* $Id: ppp-deflate.c,v 1.3 1997/04/30 06:00:45 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 "../h/param.h"
33 #include "../h/types.h"
34 #include "../h/mbuf.h"
35 #include "../h/socket.h"
36 #include "../net/net/if.h"
40 #define PACKETPTR struct mbuf *
46 * State for a Deflate (de)compressor.
48 struct deflate_state {
56 struct compstat stats;
59 #define DEFLATE_OVHD 2 /* Deflate overhead/packet */
61 static void *zalloc __P((void *, u_int items, u_int size));
62 static void zfree __P((void *, void *ptr, u_int nb));
63 static void *z_comp_alloc __P((u_char *options, int opt_len));
64 static void *z_decomp_alloc __P((u_char *options, int opt_len));
65 static void z_comp_free __P((void *state));
66 static void z_decomp_free __P((void *state));
67 static int z_comp_init __P((void *state, u_char *options, int opt_len,
68 int unit, int hdrlen, int debug));
69 static int z_decomp_init __P((void *state, u_char *options, int opt_len,
70 int unit, int hdrlen, int mru, int debug));
71 static int z_compress __P((void *state, struct mbuf **mret,
72 struct mbuf *mp, int slen, int maxolen));
73 static void z_incomp __P((void *state, struct mbuf *dmsg));
74 static int z_decompress __P((void *state, struct mbuf *cmp,
76 static void z_comp_reset __P((void *state));
77 static void z_decomp_reset __P((void *state));
78 static void z_comp_stats __P((void *state, struct compstat *stats));
81 * Procedures exported to if_ppp.c.
83 struct compressor ppp_deflate = {
84 CI_DEFLATE, /* compress_proto */
85 z_comp_alloc, /* comp_alloc */
86 z_comp_free, /* comp_free */
87 z_comp_init, /* comp_init */
88 z_comp_reset, /* comp_reset */
89 z_compress, /* compress */
90 z_comp_stats, /* comp_stat */
91 z_decomp_alloc, /* decomp_alloc */
92 z_decomp_free, /* decomp_free */
93 z_decomp_init, /* decomp_init */
94 z_decomp_reset, /* decomp_reset */
95 z_decompress, /* decompress */
96 z_incomp, /* incomp */
97 z_comp_stats, /* decomp_stat */
101 * Some useful mbuf macros not in mbuf.h.
103 #define M_IS_CLUSTER(m) ((m)->m_off > MMAXOFF)
105 #define M_TRAILINGSPACE(m) \
106 ((M_IS_CLUSTER(m) ? (u_int)(m)->m_clptr + M_CLUSTERSZ : MSIZE) \
107 - ((m)->m_off + (m)->m_len))
110 * Space allocation and freeing routines for use by zlib routines.
113 zalloc(notused, items, size)
119 KM_ALLOC(ptr, void *, items * size, KM_DEVBUF, KM_NOARG);
124 zfree(notused, ptr, nbytes)
129 KM_FREE(ptr, KM_DEVBUF);
133 * Allocate space for a compressor.
136 z_comp_alloc(options, opt_len)
140 struct deflate_state *state;
143 if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
144 || options[1] != CILEN_DEFLATE
145 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
146 || options[3] != DEFLATE_CHK_SEQUENCE)
148 w_size = DEFLATE_SIZE(options[2]);
149 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
152 KM_ALLOC(state, struct deflate_state *, sizeof(struct deflate_state),
153 KM_DEVBUF, KM_NOARG);
156 bzero(state, sizeof(struct deflate_state));
158 state->strm.next_in = NULL;
159 state->strm.zalloc = (alloc_func) zalloc;
160 state->strm.zalloc_init = (alloc_func) zalloc;
161 state->strm.zfree = (free_func) zfree;
162 if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION, DEFLATE_METHOD_VAL,
163 -w_size, 8, Z_DEFAULT_STRATEGY, DEFLATE_OVHD+2) != Z_OK) {
164 KM_FREE(state, KM_DEVBUF);
168 state->w_size = w_size;
169 bzero(&state->stats, sizeof(state->stats));
170 return (void *) state;
177 struct deflate_state *state = (struct deflate_state *) arg;
179 deflateEnd(&state->strm);
180 KM_FREE(state, KM_DEVBUF);
184 z_comp_init(arg, options, opt_len, unit, hdrlen, debug)
187 int opt_len, unit, hdrlen, debug;
189 struct deflate_state *state = (struct deflate_state *) arg;
191 if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
192 || options[1] != CILEN_DEFLATE
193 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
194 || DEFLATE_SIZE(options[2]) != state->w_size
195 || options[3] != DEFLATE_CHK_SEQUENCE)
200 state->hdrlen = hdrlen;
201 state->debug = debug;
203 deflateReset(&state->strm);
212 struct deflate_state *state = (struct deflate_state *) arg;
215 deflateReset(&state->strm);
219 z_compress(arg, mret, mp, orig_len, maxolen)
221 struct mbuf **mret; /* compressed packet (out) */
222 struct mbuf *mp; /* uncompressed packet (in) */
223 int orig_len, maxolen;
225 struct deflate_state *state = (struct deflate_state *) arg;
227 int proto, olen, wspace, r, flush;
228 struct mbuf *m, *clp;
231 * Check that the protocol is in the range we handle.
233 rptr = mtod(mp, u_char *);
234 proto = PPP_PROTOCOL(rptr);
235 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) {
240 /* Allocate one mbuf initially. */
241 if (maxolen > orig_len)
243 MGET(m, M_DONTWAIT, MT_DATA);
246 if (maxolen + state->hdrlen > MLEN) {
247 /* MCLGET is not a single statement!!! */
251 wspace = M_TRAILINGSPACE(m);
252 if (state->hdrlen > 0 && state->hdrlen + PPP_HDRLEN + 2 < wspace) {
253 m->m_off += state->hdrlen;
254 wspace -= state->hdrlen;
256 wptr = mtod(m, u_char *);
259 * Copy over the PPP header and store the 2-byte sequence number.
261 wptr[0] = PPP_ADDRESS(rptr);
262 wptr[1] = PPP_CONTROL(rptr);
263 wptr[2] = PPP_COMP >> 8;
266 wptr[0] = state->seqno >> 8;
267 wptr[1] = state->seqno;
269 state->strm.next_out = wptr;
270 state->strm.avail_out = wspace - (PPP_HDRLEN + 2);
272 state->strm.next_out = NULL;
273 state->strm.avail_out = 1000000;
279 rptr += (proto > 0xff)? 2: 3; /* skip 1st proto byte if 0 */
280 state->strm.next_in = rptr;
281 state->strm.avail_in = mtod(mp, u_char *) + mp->m_len - rptr;
283 flush = (mp == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
286 r = deflate(&state->strm, flush);
288 printf("z_compress: deflate returned %d (%s)\n",
289 r, (state->strm.msg? state->strm.msg: ""));
292 if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
293 break; /* all done */
294 if (state->strm.avail_in == 0 && mp != NULL) {
295 state->strm.next_in = mtod(mp, u_char *);
296 state->strm.avail_in = mp->m_len;
299 flush = Z_PACKET_FLUSH;
301 if (state->strm.avail_out == 0) {
305 MGET(m->m_next, M_DONTWAIT, MT_DATA);
308 if (maxolen - olen > MLEN) {
312 state->strm.next_out = mtod(m, u_char *);
313 state->strm.avail_out = wspace = M_TRAILINGSPACE(m);
317 state->strm.next_out = NULL;
318 state->strm.avail_out = 1000000;
323 olen += (m->m_len = wspace - state->strm.avail_out);
326 * See if we managed to reduce the size of the packet.
327 * If the compressor just gave us a single zero byte, it means
328 * the packet was incompressible.
330 if (m != NULL && olen < orig_len
331 && !(olen == PPP_HDRLEN + 3 && *wptr == 0)) {
332 state->stats.comp_bytes += olen;
333 state->stats.comp_packets++;
339 state->stats.inc_bytes += orig_len;
340 state->stats.inc_packets++;
343 state->stats.unc_bytes += orig_len;
344 state->stats.unc_packets++;
350 z_comp_stats(arg, stats)
352 struct compstat *stats;
354 struct deflate_state *state = (struct deflate_state *) arg;
357 *stats = state->stats;
358 stats->ratio = stats->unc_bytes;
359 out = stats->comp_bytes + stats->inc_bytes;
360 if (stats->ratio <= 0x7ffffff)
369 * Allocate space for a decompressor.
372 z_decomp_alloc(options, opt_len)
376 struct deflate_state *state;
379 if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
380 || options[1] != CILEN_DEFLATE
381 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
382 || options[3] != DEFLATE_CHK_SEQUENCE)
384 w_size = DEFLATE_SIZE(options[2]);
385 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
388 KM_ALLOC(state, struct deflate_state *, sizeof(struct deflate_state),
389 KM_DEVBUF, KM_NOARG);
392 bzero(state, sizeof(struct deflate_state));
394 state->strm.next_out = NULL;
395 state->strm.zalloc = (alloc_func) zalloc;
396 state->strm.zalloc_init = (alloc_func) zalloc;
397 state->strm.zfree = (free_func) zfree;
398 if (inflateInit2(&state->strm, -w_size) != Z_OK) {
399 KM_FREE(state, KM_DEVBUF);
403 state->w_size = w_size;
404 bzero(&state->stats, sizeof(state->stats));
405 return (void *) state;
412 struct deflate_state *state = (struct deflate_state *) arg;
414 inflateEnd(&state->strm);
415 KM_FREE(state, KM_DEVBUF);
419 z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
422 int opt_len, unit, hdrlen, mru, debug;
424 struct deflate_state *state = (struct deflate_state *) arg;
426 if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
427 || options[1] != CILEN_DEFLATE
428 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
429 || DEFLATE_SIZE(options[2]) != state->w_size
430 || options[3] != DEFLATE_CHK_SEQUENCE)
435 state->hdrlen = hdrlen;
436 state->debug = debug;
439 inflateReset(&state->strm);
448 struct deflate_state *state = (struct deflate_state *) arg;
451 inflateReset(&state->strm);
455 * Decompress a Deflate-compressed packet.
457 * Because of patent problems, we return DECOMP_ERROR for errors
458 * found by inspecting the input data and for system problems, but
459 * DECOMP_FATALERROR for any errors which could possibly be said to
460 * be being detected "after" decompression. For DECOMP_ERROR,
461 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
462 * infringing a patent of Motorola's if we do, so we take CCP down
465 * Given that the frame has the correct sequence number and a good FCS,
466 * errors such as invalid codes in the input most likely indicate a
467 * bug, so we return DECOMP_FATALERROR for them in order to turn off
468 * compression, even though they are detected by inspecting the input.
471 z_decompress(arg, mi, mop)
473 struct mbuf *mi, **mop;
475 struct deflate_state *state = (struct deflate_state *) arg;
476 struct mbuf *mo, *mo_head, *clp;
478 int rlen, olen, ospace;
479 int seq, i, flush, r, decode_proto;
480 u_char hdr[PPP_HDRLEN + DEFLATE_OVHD];
483 rptr = mtod(mi, u_char *);
485 for (i = 0; i < PPP_HDRLEN + DEFLATE_OVHD; ++i) {
490 rptr = mtod(mi, u_char *);
497 /* Check the sequence number. */
498 seq = (hdr[PPP_HDRLEN] << 8) + hdr[PPP_HDRLEN+1];
499 if (seq != state->seqno) {
501 printf("z_decompress%d: bad seq # %d, expected %d\n",
502 state->unit, seq, state->seqno);
507 /* Allocate an output mbuf. */
508 MGET(mo, M_DONTWAIT, MT_DATA);
515 ospace = M_TRAILINGSPACE(mo);
516 if (state->hdrlen > 0 && state->hdrlen + PPP_HDRLEN < ospace) {
517 mo->m_off += state->hdrlen;
518 ospace -= state->hdrlen;
522 * Fill in the first part of the PPP header. The protocol field
523 * comes from the decompressed data.
525 wptr = mtod(mo, u_char *);
526 wptr[0] = PPP_ADDRESS(hdr);
527 wptr[1] = PPP_CONTROL(hdr);
531 * Set up to call inflate. We set avail_out to 1 initially so we can
532 * look at the first byte of the output and decide whether we have
533 * a 1-byte or 2-byte protocol field.
535 state->strm.next_in = rptr;
536 state->strm.avail_in = rlen;
538 flush = (mi == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
539 rlen += PPP_HDRLEN + DEFLATE_OVHD;
540 state->strm.next_out = wptr + 3;
541 state->strm.avail_out = 1;
546 * Call inflate, supplying more input or output as needed.
549 r = inflate(&state->strm, flush);
552 printf("z_decompress%d: inflate returned %d (%s)\n",
553 state->unit, r, (state->strm.msg? state->strm.msg: ""));
555 return DECOMP_FATALERROR;
557 if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
558 break; /* all done */
559 if (state->strm.avail_in == 0 && mi != NULL) {
560 state->strm.next_in = mtod(mi, u_char *);
561 state->strm.avail_in = mi->m_len;
565 flush = Z_PACKET_FLUSH;
567 if (state->strm.avail_out == 0) {
569 state->strm.avail_out = ospace - PPP_HDRLEN;
570 if ((wptr[3] & 1) == 0) {
571 /* 2-byte protocol field */
573 --state->strm.next_out;
574 ++state->strm.avail_out;
581 MGET(mo->m_next, M_DONTWAIT, MT_DATA);
589 state->strm.next_out = mtod(mo, u_char *);
590 state->strm.avail_out = ospace = M_TRAILINGSPACE(mo);
598 olen += (mo->m_len = ospace - state->strm.avail_out);
600 state->stats.unc_bytes += olen;
601 state->stats.unc_packets++;
602 state->stats.comp_bytes += rlen;
603 state->stats.comp_packets++;
610 * Incompressible data has arrived - add it to the history.
617 struct deflate_state *state = (struct deflate_state *) arg;
622 * Check that the protocol is one we handle.
624 rptr = mtod(mi, u_char *);
625 proto = PPP_PROTOCOL(rptr);
626 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
632 * Iterate through the mbufs, adding the characters in them
633 * to the decompressor's history. For the first mbuf, we start
634 * at the either the 1st or 2nd byte of the protocol field,
635 * depending on whether the protocol value is compressible.
638 state->strm.next_in = rptr + 3;
639 state->strm.avail_in = rlen - 3;
641 --state->strm.next_in;
642 ++state->strm.avail_in;
645 r = inflateIncomp(&state->strm);
649 printf("z_incomp%d: inflateIncomp returned %d (%s)\n",
650 state->unit, r, (state->strm.msg? state->strm.msg: ""));
657 state->strm.next_in = mtod(mi, u_char *);
658 state->strm.avail_in = mi->m_len;
665 state->stats.inc_bytes += rlen;
666 state->stats.inc_packets++;
667 state->stats.unc_bytes += rlen;
668 state->stats.unc_packets++;
671 #endif /* DO_DEFLATE */