1/* $NetBSD: ppp-deflate.c,v 1.23 2016/08/06 22:38:18 pgoyette Exp $ */
2/* Id: ppp-deflate.c,v 1.5 1997/03/04 03:33:28 paulus Exp */
3
4/*
5 * ppp_deflate.c - interface the zlib procedures for Deflate compression
6 * and decompression (as used by gzip) to the PPP code.
7 * This version is for use with mbufs on BSD-derived systems.
8 *
9 * Copyright (c) 1989-2002 Paul Mackerras. All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 *
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 *
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in
20 * the documentation and/or other materials provided with the
21 * distribution.
22 *
23 * 3. The name(s) of the authors of this software must not be used to
24 * endorse or promote products derived from this software without
25 * prior written permission.
26 *
27 * 4. Redistributions of any form whatsoever must retain the following
28 * acknowledgment:
29 * "This product includes software developed by Paul Mackerras
30 * <paulus@samba.org>".
31 *
32 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
33 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
34 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
35 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
36 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
37 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
38 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
39 */
40
41#include <sys/cdefs.h>
42__KERNEL_RCSID(0, "$NetBSD: ppp-deflate.c,v 1.23 2016/08/06 22:38:18 pgoyette Exp $");
43
44#include <sys/param.h>
45#include <sys/systm.h>
46#include <sys/mbuf.h>
47#include <sys/module.h>
48#include <net/if.h>
49#include <net/ppp_defs.h>
50#include <net/if_ppp.h>
51#include <net/zlib.h>
52
53#define PACKETPTR struct mbuf *
54#include <net/ppp-comp.h>
55
56#if DO_DEFLATE
57
58#define DEFLATE_DEBUG 1
59
60/*
61 * State for a Deflate (de)compressor.
62 */
63struct deflate_state {
64 int seqno;
65 int w_size;
66 int unit;
67 int hdrlen;
68 int mru;
69 int debug;
70 z_stream strm;
71 struct compstat stats;
72};
73
74#define DEFLATE_OVHD 2 /* Deflate overhead/packet */
75
76static void *zalloc(void *, u_int items, u_int size);
77static void zfree(void *, void *ptr);
78static void *z_comp_alloc(u_char *options, int opt_len);
79static void *z_decomp_alloc(u_char *options, int opt_len);
80static void z_comp_free(void *state);
81static void z_decomp_free(void *state);
82static int z_comp_init(void *state, u_char *options, int opt_len,
83 int unit, int hdrlen, int debug);
84static int z_decomp_init(void *state, u_char *options, int opt_len,
85 int unit, int hdrlen, int mru, int debug);
86static int z_compress(void *state, struct mbuf **mret,
87 struct mbuf *mp, int slen, int maxolen);
88static void z_incomp(void *state, struct mbuf *dmsg);
89static int z_decompress(void *state, struct mbuf *cmp,
90 struct mbuf **dmpp);
91static void z_comp_reset(void *state);
92static void z_decomp_reset(void *state);
93static void z_comp_stats(void *state, struct compstat *stats);
94
95/*
96 * Procedures exported to if_ppp.c.
97 */
98static struct compressor ppp_deflate[2] = { {
99 .compress_proto = CI_DEFLATE,
100 .comp_alloc = z_comp_alloc,
101 .comp_free = z_comp_free,
102 .comp_init = z_comp_init,
103 .comp_reset = z_comp_reset,
104 .compress = z_compress,
105 .comp_stat = z_comp_stats,
106 .decomp_alloc = z_decomp_alloc,
107 .decomp_free = z_decomp_free,
108 .decomp_init = z_decomp_init,
109 .decomp_reset = z_decomp_reset,
110 .decompress = z_decompress,
111 .incomp = z_incomp,
112 .decomp_stat = z_comp_stats,
113},
114{
115 .compress_proto = CI_DEFLATE_DRAFT,
116 .comp_alloc = z_comp_alloc,
117 .comp_free = z_comp_free,
118 .comp_init = z_comp_init,
119 .comp_reset = z_comp_reset,
120 .compress = z_compress,
121 .comp_stat = z_comp_stats,
122 .decomp_alloc = z_decomp_alloc,
123 .decomp_free = z_decomp_free,
124 .decomp_init = z_decomp_init,
125 .decomp_reset = z_decomp_reset,
126 .decompress = z_decompress,
127 .incomp = z_incomp,
128 .decomp_stat = z_comp_stats,
129} };
130/*
131 * Space allocation and freeing routines for use by zlib routines.
132 */
133void *
134zalloc(void *notused, u_int items, u_int size)
135{
136 void *ptr;
137
138 ptr = malloc(items * size, M_DEVBUF, M_NOWAIT);
139 return ptr;
140}
141
142void
143zfree(void *notused, void *ptr)
144{
145 free(ptr, M_DEVBUF);
146}
147
148/*
149 * Allocate space for a compressor.
150 */
151static void *
152z_comp_alloc(u_char *options, int opt_len)
153{
154 struct deflate_state *state;
155 int w_size;
156
157 if (opt_len != CILEN_DEFLATE
158 || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
159 || options[1] != CILEN_DEFLATE
160 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
161 || options[3] != DEFLATE_CHK_SEQUENCE)
162 return NULL;
163 w_size = DEFLATE_SIZE(options[2]);
164 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
165 return NULL;
166
167 state = malloc(sizeof(struct deflate_state), M_DEVBUF, M_NOWAIT);
168 if (state == NULL)
169 return NULL;
170
171 state->strm.next_in = NULL;
172 state->strm.zalloc = zalloc;
173 state->strm.zfree = zfree;
174 if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION, DEFLATE_METHOD_VAL,
175 -w_size, 8, Z_DEFAULT_STRATEGY) != Z_OK) {
176 free(state, M_DEVBUF);
177 return NULL;
178 }
179
180 state->w_size = w_size;
181 memset(&state->stats, 0, sizeof(state->stats));
182 return (void *) state;
183}
184
185static void
186z_comp_free(void *arg)
187{
188 struct deflate_state *state = (struct deflate_state *) arg;
189
190 deflateEnd(&state->strm);
191 free(state, M_DEVBUF);
192}
193
194static int
195z_comp_init(void *arg, u_char *options, int opt_len, int unit, int hdrlen,
196 int debug)
197{
198 struct deflate_state *state = (struct deflate_state *) arg;
199
200 if (opt_len < CILEN_DEFLATE
201 || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
202 || options[1] != CILEN_DEFLATE
203 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
204 || DEFLATE_SIZE(options[2]) != state->w_size
205 || options[3] != DEFLATE_CHK_SEQUENCE)
206 return 0;
207
208 state->seqno = 0;
209 state->unit = unit;
210 state->hdrlen = hdrlen;
211 state->debug = debug;
212
213 deflateReset(&state->strm);
214
215 return 1;
216}
217
218static void
219z_comp_reset(void *arg)
220{
221 struct deflate_state *state = (struct deflate_state *) arg;
222
223 state->seqno = 0;
224 deflateReset(&state->strm);
225}
226
227int
228z_compress(void *arg,
229 struct mbuf **mret /* compressed packet (out) */,
230 struct mbuf *mp /* uncompressed packet (in) */,
231 int orig_len, int maxolen)
232{
233 struct deflate_state *state = (struct deflate_state *) arg;
234 u_char *rptr, *wptr;
235 int proto, olen, wspace, r, flush;
236 struct mbuf *m;
237
238 /*
239 * Check that the protocol is in the range we handle.
240 */
241 rptr = mtod(mp, u_char *);
242 proto = PPP_PROTOCOL(rptr);
243 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) {
244 *mret = NULL;
245 return orig_len;
246 }
247
248 /* Allocate one mbuf initially. */
249 if (maxolen > orig_len)
250 maxolen = orig_len;
251 MGET(m, M_DONTWAIT, MT_DATA);
252 *mret = m;
253 if (m != NULL) {
254 m->m_len = 0;
255 if (maxolen + state->hdrlen > MLEN)
256 MCLGET(m, M_DONTWAIT);
257 wspace = M_TRAILINGSPACE(m);
258 if (state->hdrlen + PPP_HDRLEN + 2 < wspace) {
259 m->m_data += state->hdrlen;
260 wspace -= state->hdrlen;
261 }
262 wptr = mtod(m, u_char *);
263
264 /*
265 * Copy over the PPP header and store the 2-byte sequence number.
266 */
267 wptr[0] = PPP_ADDRESS(rptr);
268 wptr[1] = PPP_CONTROL(rptr);
269 wptr[2] = PPP_COMP >> 8;
270 wptr[3] = PPP_COMP;
271 wptr += PPP_HDRLEN;
272 wptr[0] = state->seqno >> 8;
273 wptr[1] = state->seqno;
274 wptr += 2;
275 state->strm.next_out = wptr;
276 state->strm.avail_out = wspace - (PPP_HDRLEN + 2);
277 } else {
278 state->strm.next_out = NULL;
279 state->strm.avail_out = 1000000;
280 wptr = NULL;
281 wspace = 0;
282 }
283 ++state->seqno;
284
285 rptr += (proto > 0xff)? 2: 3; /* skip 1st proto byte if 0 */
286 state->strm.next_in = rptr;
287 state->strm.avail_in = mtod(mp, u_char *) + mp->m_len - rptr;
288 mp = mp->m_next;
289 flush = (mp == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
290 olen = 0;
291 for (;;) {
292 r = deflate(&state->strm, flush);
293 if (r != Z_OK) {
294 printf("z_compress: deflate returned %d (%s)\n",
295 r, (state->strm.msg? state->strm.msg: ""));
296 break;
297 }
298 if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
299 break; /* all done */
300 if (state->strm.avail_in == 0 && mp != NULL) {
301 state->strm.next_in = mtod(mp, u_char *);
302 state->strm.avail_in = mp->m_len;
303 mp = mp->m_next;
304 if (mp == NULL)
305 flush = Z_PACKET_FLUSH;
306 }
307 if (state->strm.avail_out == 0) {
308 if (m != NULL) {
309 m->m_len = wspace;
310 olen += wspace;
311 MGET(m->m_next, M_DONTWAIT, MT_DATA);
312 m = m->m_next;
313 if (m != NULL) {
314 m->m_len = 0;
315 if (maxolen - olen > MLEN)
316 MCLGET(m, M_DONTWAIT);
317 state->strm.next_out = mtod(m, u_char *);
318 state->strm.avail_out = wspace = M_TRAILINGSPACE(m);
319 }
320 }
321 if (m == NULL) {
322 state->strm.next_out = NULL;
323 state->strm.avail_out = 1000000;
324 }
325 }
326 }
327 if (m != NULL)
328 olen += (m->m_len = wspace - state->strm.avail_out);
329
330 /*
331 * See if we managed to reduce the size of the packet.
332 */
333 if (m != NULL && olen < orig_len) {
334 state->stats.comp_bytes += olen;
335 state->stats.comp_packets++;
336 } else {
337 if (*mret != NULL) {
338 m_freem(*mret);
339 *mret = NULL;
340 }
341 state->stats.inc_bytes += orig_len;
342 state->stats.inc_packets++;
343 olen = orig_len;
344 }
345 state->stats.unc_bytes += orig_len;
346 state->stats.unc_packets++;
347
348 return olen;
349}
350
351static void
352z_comp_stats(void *arg, struct compstat *stats)
353{
354 struct deflate_state *state = (struct deflate_state *) arg;
355 u_int out;
356
357 *stats = state->stats;
358 stats->ratio = stats->unc_bytes;
359 out = stats->comp_bytes + stats->inc_bytes;
360 if (stats->ratio <= 0x7ffffff)
361 stats->ratio <<= 8;
362 else
363 out >>= 8;
364 if (out != 0)
365 stats->ratio /= out;
366}
367
368/*
369 * Allocate space for a decompressor.
370 */
371static void *
372z_decomp_alloc(u_char *options, int opt_len)
373{
374 struct deflate_state *state;
375 int w_size;
376
377 if (opt_len != CILEN_DEFLATE
378 || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
379 || options[1] != CILEN_DEFLATE
380 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
381 || options[3] != DEFLATE_CHK_SEQUENCE)
382 return NULL;
383 w_size = DEFLATE_SIZE(options[2]);
384 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
385 return NULL;
386
387 state = malloc(sizeof(struct deflate_state), M_DEVBUF, M_NOWAIT);
388 if (state == NULL)
389 return NULL;
390
391 state->strm.next_out = NULL;
392 state->strm.zalloc = zalloc;
393 state->strm.zfree = zfree;
394 if (inflateInit2(&state->strm, -w_size) != Z_OK) {
395 free(state, M_DEVBUF);
396 return NULL;
397 }
398
399 state->w_size = w_size;
400 memset(&state->stats, 0, sizeof(state->stats));
401 return (void *) state;
402}
403
404static void
405z_decomp_free(void *arg)
406{
407 struct deflate_state *state = (struct deflate_state *) arg;
408
409 inflateEnd(&state->strm);
410 free(state, M_DEVBUF);
411}
412
413static int
414z_decomp_init(void *arg, u_char *options, int opt_len, int unit, int hdrlen,
415 int mru, int debug)
416{
417 struct deflate_state *state = (struct deflate_state *) arg;
418
419 if (opt_len < CILEN_DEFLATE
420 || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
421 || options[1] != CILEN_DEFLATE
422 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
423 || DEFLATE_SIZE(options[2]) != state->w_size
424 || options[3] != DEFLATE_CHK_SEQUENCE)
425 return 0;
426
427 state->seqno = 0;
428 state->unit = unit;
429 state->hdrlen = hdrlen;
430 state->debug = debug;
431 state->mru = mru;
432
433 inflateReset(&state->strm);
434
435 return 1;
436}
437
438static void
439z_decomp_reset(void *arg)
440{
441 struct deflate_state *state = (struct deflate_state *) arg;
442
443 state->seqno = 0;
444 inflateReset(&state->strm);
445}
446
447/*
448 * Decompress a Deflate-compressed packet.
449 *
450 * Because of patent problems, we return DECOMP_ERROR for errors
451 * found by inspecting the input data and for system problems, but
452 * DECOMP_FATALERROR for any errors which could possibly be said to
453 * be being detected "after" decompression. For DECOMP_ERROR,
454 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
455 * infringing a patent of Motorola's if we do, so we take CCP down
456 * instead.
457 *
458 * Given that the frame has the correct sequence number and a good FCS,
459 * errors such as invalid codes in the input most likely indicate a
460 * bug, so we return DECOMP_FATALERROR for them in order to turn off
461 * compression, even though they are detected by inspecting the input.
462 */
463int
464z_decompress(void *arg, struct mbuf *mi, struct mbuf **mop)
465{
466 struct deflate_state *state = (struct deflate_state *) arg;
467 struct mbuf *mo, *mo_head;
468 u_char *rptr, *wptr;
469 int rlen, olen, ospace;
470 int seq, i, flush, r, decode_proto;
471 u_char hdr[PPP_HDRLEN + DEFLATE_OVHD];
472
473 *mop = NULL;
474 rptr = mtod(mi, u_char *);
475 rlen = mi->m_len;
476 for (i = 0; i < PPP_HDRLEN + DEFLATE_OVHD; ++i) {
477 while (rlen <= 0) {
478 mi = mi->m_next;
479 if (mi == NULL)
480 return DECOMP_ERROR;
481 rptr = mtod(mi, u_char *);
482 rlen = mi->m_len;
483 }
484 hdr[i] = *rptr++;
485 --rlen;
486 }
487
488 /* Check the sequence number. */
489 seq = (hdr[PPP_HDRLEN] << 8) + hdr[PPP_HDRLEN+1];
490 if (seq != state->seqno) {
491 if (state->debug)
492 printf("z_decompress%d: bad seq # %d, expected %d\n",
493 state->unit, seq, state->seqno);
494 return DECOMP_ERROR;
495 }
496 ++state->seqno;
497
498 /* Allocate an output mbuf. */
499 MGETHDR(mo, M_DONTWAIT, MT_DATA);
500 if (mo == NULL)
501 return DECOMP_ERROR;
502 mo_head = mo;
503 mo->m_len = 0;
504 mo->m_next = NULL;
505 MCLGET(mo, M_DONTWAIT);
506 ospace = M_TRAILINGSPACE(mo);
507 if (state->hdrlen + PPP_HDRLEN < ospace) {
508 mo->m_data += state->hdrlen;
509 ospace -= state->hdrlen;
510 }
511
512 /*
513 * Fill in the first part of the PPP header. The protocol field
514 * comes from the decompressed data.
515 */
516 wptr = mtod(mo, u_char *);
517 wptr[0] = PPP_ADDRESS(hdr);
518 wptr[1] = PPP_CONTROL(hdr);
519 wptr[2] = 0;
520
521 /*
522 * Set up to call inflate. We set avail_out to 1 initially so we can
523 * look at the first byte of the output and decide whether we have
524 * a 1-byte or 2-byte protocol field.
525 */
526 state->strm.next_in = rptr;
527 state->strm.avail_in = rlen;
528 mi = mi->m_next;
529 flush = (mi == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
530 rlen += PPP_HDRLEN + DEFLATE_OVHD;
531 state->strm.next_out = wptr + 3;
532 state->strm.avail_out = 1;
533 decode_proto = 1;
534 olen = 0;
535
536 /*
537 * Call inflate, supplying more input or output as needed.
538 */
539 for (;;) {
540 r = inflate(&state->strm, flush);
541 if (r != Z_OK) {
542#if !DEFLATE_DEBUG
543 if (state->debug)
544#endif
545 printf("z_decompress%d: inflate returned %d (%s)\n",
546 state->unit, r, (state->strm.msg? state->strm.msg: ""));
547 m_freem(mo_head);
548 return DECOMP_FATALERROR;
549 }
550 if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
551 break; /* all done */
552 if (state->strm.avail_in == 0 && mi != NULL) {
553 state->strm.next_in = mtod(mi, u_char *);
554 state->strm.avail_in = mi->m_len;
555 rlen += mi->m_len;
556 mi = mi->m_next;
557 if (mi == NULL)
558 flush = Z_PACKET_FLUSH;
559 }
560 if (state->strm.avail_out == 0) {
561 if (decode_proto) {
562 state->strm.avail_out = ospace - PPP_HDRLEN;
563 if ((wptr[3] & 1) == 0) {
564 /* 2-byte protocol field */
565 wptr[2] = wptr[3];
566 --state->strm.next_out;
567 ++state->strm.avail_out;
568 --olen;
569 }
570 decode_proto = 0;
571 } else {
572 mo->m_len = ospace;
573 olen += ospace;
574 MGET(mo->m_next, M_DONTWAIT, MT_DATA);
575 mo = mo->m_next;
576 if (mo == NULL) {
577 m_freem(mo_head);
578 return DECOMP_ERROR;
579 }
580 MCLGET(mo, M_DONTWAIT);
581 state->strm.next_out = mtod(mo, u_char *);
582 state->strm.avail_out = ospace = M_TRAILINGSPACE(mo);
583 }
584 }
585 }
586 if (decode_proto) {
587 m_freem(mo_head);
588 return DECOMP_ERROR;
589 }
590 olen += (mo->m_len = ospace - state->strm.avail_out);
591#if DEFLATE_DEBUG
592 if (olen > state->mru + PPP_HDRLEN)
593 printf("ppp_deflate%d: exceeded mru (%d > %d)\n",
594 state->unit, olen, state->mru + PPP_HDRLEN);
595#endif
596
597 state->stats.unc_bytes += olen;
598 state->stats.unc_packets++;
599 state->stats.comp_bytes += rlen;
600 state->stats.comp_packets++;
601
602 *mop = mo_head;
603 return DECOMP_OK;
604}
605
606/*
607 * Incompressible data has arrived - add it to the history.
608 */
609static void
610z_incomp(void *arg, struct mbuf *mi)
611{
612 struct deflate_state *state = (struct deflate_state *) arg;
613 u_char *rptr;
614 int rlen, proto, r;
615
616 /*
617 * Check that the protocol is one we handle.
618 */
619 rptr = mtod(mi, u_char *);
620 proto = PPP_PROTOCOL(rptr);
621 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
622 return;
623
624 ++state->seqno;
625
626 /*
627 * Iterate through the mbufs, adding the characters in them
628 * to the decompressor's history. For the first mbuf, we start
629 * at the either the 1st or 2nd byte of the protocol field,
630 * depending on whether the protocol value is compressible.
631 */
632 rlen = mi->m_len;
633 state->strm.next_in = rptr + 3;
634 state->strm.avail_in = rlen - 3;
635 if (proto > 0xff) {
636 --state->strm.next_in;
637 ++state->strm.avail_in;
638 }
639 for (;;) {
640 r = inflateIncomp(&state->strm);
641 if (r != Z_OK) {
642 /* gak! */
643#if !DEFLATE_DEBUG
644 if (state->debug)
645#endif
646 printf("z_incomp%d: inflateIncomp returned %d (%s)\n",
647 state->unit, r, (state->strm.msg? state->strm.msg: ""));
648 return;
649 }
650 mi = mi->m_next;
651 if (mi == NULL)
652 break;
653 state->strm.next_in = mtod(mi, u_char *);
654 state->strm.avail_in = mi->m_len;
655 rlen += mi->m_len;
656 }
657
658 /*
659 * Update stats.
660 */
661 state->stats.inc_bytes += rlen;
662 state->stats.inc_packets++;
663 state->stats.unc_bytes += rlen;
664 state->stats.unc_packets++;
665}
666
667MODULE(MODULE_CLASS_MISC, ppp_deflate, "zlib,if_ppp");
668
669static int
670ppp_deflate_modcmd(modcmd_t cmd, void *arg)
671{
672
673 switch (cmd) {
674 case MODULE_CMD_INIT:
675 return ppp_register_compressor(ppp_deflate, 2);
676 case MODULE_CMD_FINI:
677 return ppp_unregister_compressor(ppp_deflate, 2);
678 case MODULE_CMD_STAT:
679 return 0;
680 default:
681 return ENOTTY;
682 }
683
684 return ENOTTY;
685}
686#endif /* DO_DEFLATE */
687