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1/*
2 * ppp_deflate.c - interface the zlib procedures for Deflate compression
3 * and decompression (as used by gzip) to the PPP code.
4 *
5 * Copyright 1994-1998 Paul Mackerras.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * version 2 as published by the Free Software Foundation.
10 */
11
12#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/vmalloc.h>
15#include <linux/init.h>
16#include <linux/string.h>
17
18#include <linux/ppp_defs.h>
19#include <linux/ppp-comp.h>
20
21#include <linux/zlib.h>
22#include <asm/unaligned.h>
23
24/*
25 * State for a Deflate (de)compressor.
26 */
27struct ppp_deflate_state {
28 int seqno;
29 int w_size;
30 int unit;
31 int mru;
32 int debug;
33 z_stream strm;
34 struct compstat stats;
35};
36
37#define DEFLATE_OVHD 2 /* Deflate overhead/packet */
38
39static void *z_comp_alloc(unsigned char *options, int opt_len);
40static void *z_decomp_alloc(unsigned char *options, int opt_len);
41static void z_comp_free(void *state);
42static void z_decomp_free(void *state);
43static int z_comp_init(void *state, unsigned char *options,
44 int opt_len,
45 int unit, int hdrlen, int debug);
46static int z_decomp_init(void *state, unsigned char *options,
47 int opt_len,
48 int unit, int hdrlen, int mru, int debug);
49static int z_compress(void *state, unsigned char *rptr,
50 unsigned char *obuf,
51 int isize, int osize);
52static void z_incomp(void *state, unsigned char *ibuf, int icnt);
53static int z_decompress(void *state, unsigned char *ibuf,
54 int isize, unsigned char *obuf, int osize);
55static void z_comp_reset(void *state);
56static void z_decomp_reset(void *state);
57static void z_comp_stats(void *state, struct compstat *stats);
58
59/**
60 * z_comp_free - free the memory used by a compressor
61 * @arg: pointer to the private state for the compressor.
62 */
63static void z_comp_free(void *arg)
64{
65 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
66
67 if (state) {
68 zlib_deflateEnd(&state->strm);
69 vfree(state->strm.workspace);
70 kfree(state);
71 }
72}
73
74/**
75 * z_comp_alloc - allocate space for a compressor.
76 * @options: pointer to CCP option data
77 * @opt_len: length of the CCP option at @options.
78 *
79 * The @options pointer points to the a buffer containing the
80 * CCP option data for the compression being negotiated. It is
81 * formatted according to RFC1979, and describes the window
82 * size that the peer is requesting that we use in compressing
83 * data to be sent to it.
84 *
85 * Returns the pointer to the private state for the compressor,
86 * or NULL if we could not allocate enough memory.
87 */
88static void *z_comp_alloc(unsigned char *options, int opt_len)
89{
90 struct ppp_deflate_state *state;
91 int w_size;
92
93 if (opt_len != CILEN_DEFLATE ||
94 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
95 options[1] != CILEN_DEFLATE ||
96 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
97 options[3] != DEFLATE_CHK_SEQUENCE)
98 return NULL;
99 w_size = DEFLATE_SIZE(options[2]);
100 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
101 return NULL;
102
103 state = kzalloc(sizeof(*state),
104 GFP_KERNEL);
105 if (state == NULL)
106 return NULL;
107
108 state->strm.next_in = NULL;
109 state->w_size = w_size;
110 state->strm.workspace = vmalloc(zlib_deflate_workspacesize(-w_size, 8));
111 if (state->strm.workspace == NULL)
112 goto out_free;
113
114 if (zlib_deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION,
115 DEFLATE_METHOD_VAL, -w_size, 8, Z_DEFAULT_STRATEGY)
116 != Z_OK)
117 goto out_free;
118 return (void *) state;
119
120out_free:
121 z_comp_free(state);
122 return NULL;
123}
124
125/**
126 * z_comp_init - initialize a previously-allocated compressor.
127 * @arg: pointer to the private state for the compressor
128 * @options: pointer to the CCP option data describing the
129 * compression that was negotiated with the peer
130 * @opt_len: length of the CCP option data at @options
131 * @unit: PPP unit number for diagnostic messages
132 * @hdrlen: ignored (present for backwards compatibility)
133 * @debug: debug flag; if non-zero, debug messages are printed.
134 *
135 * The CCP options described by @options must match the options
136 * specified when the compressor was allocated. The compressor
137 * history is reset. Returns 0 for failure (CCP options don't
138 * match) or 1 for success.
139 */
140static int z_comp_init(void *arg, unsigned char *options, int opt_len,
141 int unit, int hdrlen, int debug)
142{
143 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
144
145 if (opt_len < CILEN_DEFLATE ||
146 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
147 options[1] != CILEN_DEFLATE ||
148 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
149 DEFLATE_SIZE(options[2]) != state->w_size ||
150 options[3] != DEFLATE_CHK_SEQUENCE)
151 return 0;
152
153 state->seqno = 0;
154 state->unit = unit;
155 state->debug = debug;
156
157 zlib_deflateReset(&state->strm);
158
159 return 1;
160}
161
162/**
163 * z_comp_reset - reset a previously-allocated compressor.
164 * @arg: pointer to private state for the compressor.
165 *
166 * This clears the history for the compressor and makes it
167 * ready to start emitting a new compressed stream.
168 */
169static void z_comp_reset(void *arg)
170{
171 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
172
173 state->seqno = 0;
174 zlib_deflateReset(&state->strm);
175}
176
177/**
178 * z_compress - compress a PPP packet with Deflate compression.
179 * @arg: pointer to private state for the compressor
180 * @rptr: uncompressed packet (input)
181 * @obuf: compressed packet (output)
182 * @isize: size of uncompressed packet
183 * @osize: space available at @obuf
184 *
185 * Returns the length of the compressed packet, or 0 if the
186 * packet is incompressible.
187 */
188static int z_compress(void *arg, unsigned char *rptr, unsigned char *obuf,
189 int isize, int osize)
190{
191 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
192 int r, proto, off, olen, oavail;
193 unsigned char *wptr;
194
195 /*
196 * Check that the protocol is in the range we handle.
197 */
198 proto = PPP_PROTOCOL(rptr);
199 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
200 return 0;
201
202 /* Don't generate compressed packets which are larger than
203 the uncompressed packet. */
204 if (osize > isize)
205 osize = isize;
206
207 wptr = obuf;
208
209 /*
210 * Copy over the PPP header and store the 2-byte sequence number.
211 */
212 wptr[0] = PPP_ADDRESS(rptr);
213 wptr[1] = PPP_CONTROL(rptr);
214 put_unaligned_be16(PPP_COMP, wptr + 2);
215 wptr += PPP_HDRLEN;
216 put_unaligned_be16(state->seqno, wptr);
217 wptr += DEFLATE_OVHD;
218 olen = PPP_HDRLEN + DEFLATE_OVHD;
219 state->strm.next_out = wptr;
220 state->strm.avail_out = oavail = osize - olen;
221 ++state->seqno;
222
223 off = (proto > 0xff) ? 2 : 3; /* skip 1st proto byte if 0 */
224 rptr += off;
225 state->strm.next_in = rptr;
226 state->strm.avail_in = (isize - off);
227
228 for (;;) {
229 r = zlib_deflate(&state->strm, Z_PACKET_FLUSH);
230 if (r != Z_OK) {
231 if (state->debug)
232 printk(KERN_ERR
233 "z_compress: deflate returned %d\n", r);
234 break;
235 }
236 if (state->strm.avail_out == 0) {
237 olen += oavail;
238 state->strm.next_out = NULL;
239 state->strm.avail_out = oavail = 1000000;
240 } else {
241 break; /* all done */
242 }
243 }
244 olen += oavail - state->strm.avail_out;
245
246 /*
247 * See if we managed to reduce the size of the packet.
248 */
249 if (olen < isize && olen <= osize) {
250 state->stats.comp_bytes += olen;
251 state->stats.comp_packets++;
252 } else {
253 state->stats.inc_bytes += isize;
254 state->stats.inc_packets++;
255 olen = 0;
256 }
257 state->stats.unc_bytes += isize;
258 state->stats.unc_packets++;
259
260 return olen;
261}
262
263/**
264 * z_comp_stats - return compression statistics for a compressor
265 * or decompressor.
266 * @arg: pointer to private space for the (de)compressor
267 * @stats: pointer to a struct compstat to receive the result.
268 */
269static void z_comp_stats(void *arg, struct compstat *stats)
270{
271 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
272
273 *stats = state->stats;
274}
275
276/**
277 * z_decomp_free - Free the memory used by a decompressor.
278 * @arg: pointer to private space for the decompressor.
279 */
280static void z_decomp_free(void *arg)
281{
282 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
283
284 if (state) {
285 zlib_inflateEnd(&state->strm);
286 vfree(state->strm.workspace);
287 kfree(state);
288 }
289}
290
291/**
292 * z_decomp_alloc - allocate space for a decompressor.
293 * @options: pointer to CCP option data
294 * @opt_len: length of the CCP option at @options.
295 *
296 * The @options pointer points to the a buffer containing the
297 * CCP option data for the compression being negotiated. It is
298 * formatted according to RFC1979, and describes the window
299 * size that we are requesting the peer to use in compressing
300 * data to be sent to us.
301 *
302 * Returns the pointer to the private state for the decompressor,
303 * or NULL if we could not allocate enough memory.
304 */
305static void *z_decomp_alloc(unsigned char *options, int opt_len)
306{
307 struct ppp_deflate_state *state;
308 int w_size;
309
310 if (opt_len != CILEN_DEFLATE ||
311 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
312 options[1] != CILEN_DEFLATE ||
313 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
314 options[3] != DEFLATE_CHK_SEQUENCE)
315 return NULL;
316 w_size = DEFLATE_SIZE(options[2]);
317 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
318 return NULL;
319
320 state = kzalloc(sizeof(*state), GFP_KERNEL);
321 if (state == NULL)
322 return NULL;
323
324 state->w_size = w_size;
325 state->strm.next_out = NULL;
326 state->strm.workspace = vmalloc(zlib_inflate_workspacesize());
327 if (state->strm.workspace == NULL)
328 goto out_free;
329
330 if (zlib_inflateInit2(&state->strm, -w_size) != Z_OK)
331 goto out_free;
332 return (void *) state;
333
334out_free:
335 z_decomp_free(state);
336 return NULL;
337}
338
339/**
340 * z_decomp_init - initialize a previously-allocated decompressor.
341 * @arg: pointer to the private state for the decompressor
342 * @options: pointer to the CCP option data describing the
343 * compression that was negotiated with the peer
344 * @opt_len: length of the CCP option data at @options
345 * @unit: PPP unit number for diagnostic messages
346 * @hdrlen: ignored (present for backwards compatibility)
347 * @mru: maximum length of decompressed packets
348 * @debug: debug flag; if non-zero, debug messages are printed.
349 *
350 * The CCP options described by @options must match the options
351 * specified when the decompressor was allocated. The decompressor
352 * history is reset. Returns 0 for failure (CCP options don't
353 * match) or 1 for success.
354 */
355static int z_decomp_init(void *arg, unsigned char *options, int opt_len,
356 int unit, int hdrlen, int mru, int debug)
357{
358 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
359
360 if (opt_len < CILEN_DEFLATE ||
361 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
362 options[1] != CILEN_DEFLATE ||
363 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
364 DEFLATE_SIZE(options[2]) != state->w_size ||
365 options[3] != DEFLATE_CHK_SEQUENCE)
366 return 0;
367
368 state->seqno = 0;
369 state->unit = unit;
370 state->debug = debug;
371 state->mru = mru;
372
373 zlib_inflateReset(&state->strm);
374
375 return 1;
376}
377
378/**
379 * z_decomp_reset - reset a previously-allocated decompressor.
380 * @arg: pointer to private state for the decompressor.
381 *
382 * This clears the history for the decompressor and makes it
383 * ready to receive a new compressed stream.
384 */
385static void z_decomp_reset(void *arg)
386{
387 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
388
389 state->seqno = 0;
390 zlib_inflateReset(&state->strm);
391}
392
393/**
394 * z_decompress - decompress a Deflate-compressed packet.
395 * @arg: pointer to private state for the decompressor
396 * @ibuf: pointer to input (compressed) packet data
397 * @isize: length of input packet
398 * @obuf: pointer to space for output (decompressed) packet
399 * @osize: amount of space available at @obuf
400 *
401 * Because of patent problems, we return DECOMP_ERROR for errors
402 * found by inspecting the input data and for system problems, but
403 * DECOMP_FATALERROR for any errors which could possibly be said to
404 * be being detected "after" decompression. For DECOMP_ERROR,
405 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
406 * infringing a patent of Motorola's if we do, so we take CCP down
407 * instead.
408 *
409 * Given that the frame has the correct sequence number and a good FCS,
410 * errors such as invalid codes in the input most likely indicate a
411 * bug, so we return DECOMP_FATALERROR for them in order to turn off
412 * compression, even though they are detected by inspecting the input.
413 */
414static int z_decompress(void *arg, unsigned char *ibuf, int isize,
415 unsigned char *obuf, int osize)
416{
417 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
418 int olen, seq, r;
419 int decode_proto, overflow;
420 unsigned char overflow_buf[1];
421
422 if (isize <= PPP_HDRLEN + DEFLATE_OVHD) {
423 if (state->debug)
424 printk(KERN_DEBUG "z_decompress%d: short pkt (%d)\n",
425 state->unit, isize);
426 return DECOMP_ERROR;
427 }
428
429 /* Check the sequence number. */
430 seq = get_unaligned_be16(ibuf + PPP_HDRLEN);
431 if (seq != (state->seqno & 0xffff)) {
432 if (state->debug)
433 printk(KERN_DEBUG "z_decompress%d: bad seq # %d, expected %d\n",
434 state->unit, seq, state->seqno & 0xffff);
435 return DECOMP_ERROR;
436 }
437 ++state->seqno;
438
439 /*
440 * Fill in the first part of the PPP header. The protocol field
441 * comes from the decompressed data.
442 */
443 obuf[0] = PPP_ADDRESS(ibuf);
444 obuf[1] = PPP_CONTROL(ibuf);
445 obuf[2] = 0;
446
447 /*
448 * Set up to call inflate. We set avail_out to 1 initially so we can
449 * look at the first byte of the output and decide whether we have
450 * a 1-byte or 2-byte protocol field.
451 */
452 state->strm.next_in = ibuf + PPP_HDRLEN + DEFLATE_OVHD;
453 state->strm.avail_in = isize - (PPP_HDRLEN + DEFLATE_OVHD);
454 state->strm.next_out = obuf + 3;
455 state->strm.avail_out = 1;
456 decode_proto = 1;
457 overflow = 0;
458
459 /*
460 * Call inflate, supplying more input or output as needed.
461 */
462 for (;;) {
463 r = zlib_inflate(&state->strm, Z_PACKET_FLUSH);
464 if (r != Z_OK) {
465 if (state->debug)
466 printk(KERN_DEBUG "z_decompress%d: inflate returned %d (%s)\n",
467 state->unit, r, (state->strm.msg? state->strm.msg: ""));
468 return DECOMP_FATALERROR;
469 }
470 if (state->strm.avail_out != 0)
471 break; /* all done */
472 if (decode_proto) {
473 state->strm.avail_out = osize - PPP_HDRLEN;
474 if ((obuf[3] & 1) == 0) {
475 /* 2-byte protocol field */
476 obuf[2] = obuf[3];
477 --state->strm.next_out;
478 ++state->strm.avail_out;
479 }
480 decode_proto = 0;
481 } else if (!overflow) {
482 /*
483 * We've filled up the output buffer; the only way to
484 * find out whether inflate has any more characters
485 * left is to give it another byte of output space.
486 */
487 state->strm.next_out = overflow_buf;
488 state->strm.avail_out = 1;
489 overflow = 1;
490 } else {
491 if (state->debug)
492 printk(KERN_DEBUG "z_decompress%d: ran out of mru\n",
493 state->unit);
494 return DECOMP_FATALERROR;
495 }
496 }
497
498 if (decode_proto) {
499 if (state->debug)
500 printk(KERN_DEBUG "z_decompress%d: didn't get proto\n",
501 state->unit);
502 return DECOMP_ERROR;
503 }
504
505 olen = osize + overflow - state->strm.avail_out;
506 state->stats.unc_bytes += olen;
507 state->stats.unc_packets++;
508 state->stats.comp_bytes += isize;
509 state->stats.comp_packets++;
510
511 return olen;
512}
513
514/**
515 * z_incomp - add incompressible input data to the history.
516 * @arg: pointer to private state for the decompressor
517 * @ibuf: pointer to input packet data
518 * @icnt: length of input data.
519 */
520static void z_incomp(void *arg, unsigned char *ibuf, int icnt)
521{
522 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
523 int proto, r;
524
525 /*
526 * Check that the protocol is one we handle.
527 */
528 proto = PPP_PROTOCOL(ibuf);
529 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
530 return;
531
532 ++state->seqno;
533
534 /*
535 * We start at the either the 1st or 2nd byte of the protocol field,
536 * depending on whether the protocol value is compressible.
537 */
538 state->strm.next_in = ibuf + 3;
539 state->strm.avail_in = icnt - 3;
540 if (proto > 0xff) {
541 --state->strm.next_in;
542 ++state->strm.avail_in;
543 }
544
545 r = zlib_inflateIncomp(&state->strm);
546 if (r != Z_OK) {
547 /* gak! */
548 if (state->debug) {
549 printk(KERN_DEBUG "z_incomp%d: inflateIncomp returned %d (%s)\n",
550 state->unit, r, (state->strm.msg? state->strm.msg: ""));
551 }
552 return;
553 }
554
555 /*
556 * Update stats.
557 */
558 state->stats.inc_bytes += icnt;
559 state->stats.inc_packets++;
560 state->stats.unc_bytes += icnt;
561 state->stats.unc_packets++;
562}
563
564/*************************************************************
565 * Module interface table
566 *************************************************************/
567
568/* These are in ppp_generic.c */
569extern int ppp_register_compressor (struct compressor *cp);
570extern void ppp_unregister_compressor (struct compressor *cp);
571
572/*
573 * Procedures exported to if_ppp.c.
574 */
575static struct compressor ppp_deflate = {
576 .compress_proto = CI_DEFLATE,
577 .comp_alloc = z_comp_alloc,
578 .comp_free = z_comp_free,
579 .comp_init = z_comp_init,
580 .comp_reset = z_comp_reset,
581 .compress = z_compress,
582 .comp_stat = z_comp_stats,
583 .decomp_alloc = z_decomp_alloc,
584 .decomp_free = z_decomp_free,
585 .decomp_init = z_decomp_init,
586 .decomp_reset = z_decomp_reset,
587 .decompress = z_decompress,
588 .incomp = z_incomp,
589 .decomp_stat = z_comp_stats,
590 .owner = THIS_MODULE
591};
592
593static struct compressor ppp_deflate_draft = {
594 .compress_proto = CI_DEFLATE_DRAFT,
595 .comp_alloc = z_comp_alloc,
596 .comp_free = z_comp_free,
597 .comp_init = z_comp_init,
598 .comp_reset = z_comp_reset,
599 .compress = z_compress,
600 .comp_stat = z_comp_stats,
601 .decomp_alloc = z_decomp_alloc,
602 .decomp_free = z_decomp_free,
603 .decomp_init = z_decomp_init,
604 .decomp_reset = z_decomp_reset,
605 .decompress = z_decompress,
606 .incomp = z_incomp,
607 .decomp_stat = z_comp_stats,
608 .owner = THIS_MODULE
609};
610
611static int __init deflate_init(void)
612{
613 int answer = ppp_register_compressor(&ppp_deflate);
614 if (answer == 0)
615 printk(KERN_INFO
616 "PPP Deflate Compression module registered\n");
617 ppp_register_compressor(&ppp_deflate_draft);
618 return answer;
619}
620
621static void __exit deflate_cleanup(void)
622{
623 ppp_unregister_compressor(&ppp_deflate);
624 ppp_unregister_compressor(&ppp_deflate_draft);
625}
626
627module_init(deflate_init);
628module_exit(deflate_cleanup);
629MODULE_LICENSE("Dual BSD/GPL");
630MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE));
631MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE_DRAFT));
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * ppp_deflate.c - interface the zlib procedures for Deflate compression
4 * and decompression (as used by gzip) to the PPP code.
5 *
6 * Copyright 1994-1998 Paul Mackerras.
7 */
8
9#include <linux/module.h>
10#include <linux/slab.h>
11#include <linux/vmalloc.h>
12#include <linux/init.h>
13#include <linux/string.h>
14
15#include <linux/ppp_defs.h>
16#include <linux/ppp-comp.h>
17
18#include <linux/zlib.h>
19#include <asm/unaligned.h>
20
21/*
22 * State for a Deflate (de)compressor.
23 */
24struct ppp_deflate_state {
25 int seqno;
26 int w_size;
27 int unit;
28 int mru;
29 int debug;
30 z_stream strm;
31 struct compstat stats;
32};
33
34#define DEFLATE_OVHD 2 /* Deflate overhead/packet */
35
36static void *z_comp_alloc(unsigned char *options, int opt_len);
37static void *z_decomp_alloc(unsigned char *options, int opt_len);
38static void z_comp_free(void *state);
39static void z_decomp_free(void *state);
40static int z_comp_init(void *state, unsigned char *options,
41 int opt_len,
42 int unit, int hdrlen, int debug);
43static int z_decomp_init(void *state, unsigned char *options,
44 int opt_len,
45 int unit, int hdrlen, int mru, int debug);
46static int z_compress(void *state, unsigned char *rptr,
47 unsigned char *obuf,
48 int isize, int osize);
49static void z_incomp(void *state, unsigned char *ibuf, int icnt);
50static int z_decompress(void *state, unsigned char *ibuf,
51 int isize, unsigned char *obuf, int osize);
52static void z_comp_reset(void *state);
53static void z_decomp_reset(void *state);
54static void z_comp_stats(void *state, struct compstat *stats);
55
56/**
57 * z_comp_free - free the memory used by a compressor
58 * @arg: pointer to the private state for the compressor.
59 */
60static void z_comp_free(void *arg)
61{
62 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
63
64 if (state) {
65 zlib_deflateEnd(&state->strm);
66 vfree(state->strm.workspace);
67 kfree(state);
68 }
69}
70
71/**
72 * z_comp_alloc - allocate space for a compressor.
73 * @options: pointer to CCP option data
74 * @opt_len: length of the CCP option at @options.
75 *
76 * The @options pointer points to the a buffer containing the
77 * CCP option data for the compression being negotiated. It is
78 * formatted according to RFC1979, and describes the window
79 * size that the peer is requesting that we use in compressing
80 * data to be sent to it.
81 *
82 * Returns the pointer to the private state for the compressor,
83 * or NULL if we could not allocate enough memory.
84 */
85static void *z_comp_alloc(unsigned char *options, int opt_len)
86{
87 struct ppp_deflate_state *state;
88 int w_size;
89
90 if (opt_len != CILEN_DEFLATE ||
91 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
92 options[1] != CILEN_DEFLATE ||
93 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
94 options[3] != DEFLATE_CHK_SEQUENCE)
95 return NULL;
96 w_size = DEFLATE_SIZE(options[2]);
97 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
98 return NULL;
99
100 state = kzalloc(sizeof(*state),
101 GFP_KERNEL);
102 if (state == NULL)
103 return NULL;
104
105 state->strm.next_in = NULL;
106 state->w_size = w_size;
107 state->strm.workspace = vmalloc(zlib_deflate_workspacesize(-w_size, 8));
108 if (state->strm.workspace == NULL)
109 goto out_free;
110
111 if (zlib_deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION,
112 DEFLATE_METHOD_VAL, -w_size, 8, Z_DEFAULT_STRATEGY)
113 != Z_OK)
114 goto out_free;
115 return (void *) state;
116
117out_free:
118 z_comp_free(state);
119 return NULL;
120}
121
122/**
123 * z_comp_init - initialize a previously-allocated compressor.
124 * @arg: pointer to the private state for the compressor
125 * @options: pointer to the CCP option data describing the
126 * compression that was negotiated with the peer
127 * @opt_len: length of the CCP option data at @options
128 * @unit: PPP unit number for diagnostic messages
129 * @hdrlen: ignored (present for backwards compatibility)
130 * @debug: debug flag; if non-zero, debug messages are printed.
131 *
132 * The CCP options described by @options must match the options
133 * specified when the compressor was allocated. The compressor
134 * history is reset. Returns 0 for failure (CCP options don't
135 * match) or 1 for success.
136 */
137static int z_comp_init(void *arg, unsigned char *options, int opt_len,
138 int unit, int hdrlen, int debug)
139{
140 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
141
142 if (opt_len < CILEN_DEFLATE ||
143 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
144 options[1] != CILEN_DEFLATE ||
145 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
146 DEFLATE_SIZE(options[2]) != state->w_size ||
147 options[3] != DEFLATE_CHK_SEQUENCE)
148 return 0;
149
150 state->seqno = 0;
151 state->unit = unit;
152 state->debug = debug;
153
154 zlib_deflateReset(&state->strm);
155
156 return 1;
157}
158
159/**
160 * z_comp_reset - reset a previously-allocated compressor.
161 * @arg: pointer to private state for the compressor.
162 *
163 * This clears the history for the compressor and makes it
164 * ready to start emitting a new compressed stream.
165 */
166static void z_comp_reset(void *arg)
167{
168 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
169
170 state->seqno = 0;
171 zlib_deflateReset(&state->strm);
172}
173
174/**
175 * z_compress - compress a PPP packet with Deflate compression.
176 * @arg: pointer to private state for the compressor
177 * @rptr: uncompressed packet (input)
178 * @obuf: compressed packet (output)
179 * @isize: size of uncompressed packet
180 * @osize: space available at @obuf
181 *
182 * Returns the length of the compressed packet, or 0 if the
183 * packet is incompressible.
184 */
185static int z_compress(void *arg, unsigned char *rptr, unsigned char *obuf,
186 int isize, int osize)
187{
188 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
189 int r, proto, off, olen, oavail;
190 unsigned char *wptr;
191
192 /*
193 * Check that the protocol is in the range we handle.
194 */
195 proto = PPP_PROTOCOL(rptr);
196 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
197 return 0;
198
199 /* Don't generate compressed packets which are larger than
200 the uncompressed packet. */
201 if (osize > isize)
202 osize = isize;
203
204 wptr = obuf;
205
206 /*
207 * Copy over the PPP header and store the 2-byte sequence number.
208 */
209 wptr[0] = PPP_ADDRESS(rptr);
210 wptr[1] = PPP_CONTROL(rptr);
211 put_unaligned_be16(PPP_COMP, wptr + 2);
212 wptr += PPP_HDRLEN;
213 put_unaligned_be16(state->seqno, wptr);
214 wptr += DEFLATE_OVHD;
215 olen = PPP_HDRLEN + DEFLATE_OVHD;
216 state->strm.next_out = wptr;
217 state->strm.avail_out = oavail = osize - olen;
218 ++state->seqno;
219
220 off = (proto > 0xff) ? 2 : 3; /* skip 1st proto byte if 0 */
221 rptr += off;
222 state->strm.next_in = rptr;
223 state->strm.avail_in = (isize - off);
224
225 for (;;) {
226 r = zlib_deflate(&state->strm, Z_PACKET_FLUSH);
227 if (r != Z_OK) {
228 if (state->debug)
229 printk(KERN_ERR
230 "z_compress: deflate returned %d\n", r);
231 break;
232 }
233 if (state->strm.avail_out == 0) {
234 olen += oavail;
235 state->strm.next_out = NULL;
236 state->strm.avail_out = oavail = 1000000;
237 } else {
238 break; /* all done */
239 }
240 }
241 olen += oavail - state->strm.avail_out;
242
243 /*
244 * See if we managed to reduce the size of the packet.
245 */
246 if (olen < isize && olen <= osize) {
247 state->stats.comp_bytes += olen;
248 state->stats.comp_packets++;
249 } else {
250 state->stats.inc_bytes += isize;
251 state->stats.inc_packets++;
252 olen = 0;
253 }
254 state->stats.unc_bytes += isize;
255 state->stats.unc_packets++;
256
257 return olen;
258}
259
260/**
261 * z_comp_stats - return compression statistics for a compressor
262 * or decompressor.
263 * @arg: pointer to private space for the (de)compressor
264 * @stats: pointer to a struct compstat to receive the result.
265 */
266static void z_comp_stats(void *arg, struct compstat *stats)
267{
268 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
269
270 *stats = state->stats;
271}
272
273/**
274 * z_decomp_free - Free the memory used by a decompressor.
275 * @arg: pointer to private space for the decompressor.
276 */
277static void z_decomp_free(void *arg)
278{
279 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
280
281 if (state) {
282 zlib_inflateEnd(&state->strm);
283 vfree(state->strm.workspace);
284 kfree(state);
285 }
286}
287
288/**
289 * z_decomp_alloc - allocate space for a decompressor.
290 * @options: pointer to CCP option data
291 * @opt_len: length of the CCP option at @options.
292 *
293 * The @options pointer points to the a buffer containing the
294 * CCP option data for the compression being negotiated. It is
295 * formatted according to RFC1979, and describes the window
296 * size that we are requesting the peer to use in compressing
297 * data to be sent to us.
298 *
299 * Returns the pointer to the private state for the decompressor,
300 * or NULL if we could not allocate enough memory.
301 */
302static void *z_decomp_alloc(unsigned char *options, int opt_len)
303{
304 struct ppp_deflate_state *state;
305 int w_size;
306
307 if (opt_len != CILEN_DEFLATE ||
308 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
309 options[1] != CILEN_DEFLATE ||
310 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
311 options[3] != DEFLATE_CHK_SEQUENCE)
312 return NULL;
313 w_size = DEFLATE_SIZE(options[2]);
314 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
315 return NULL;
316
317 state = kzalloc(sizeof(*state), GFP_KERNEL);
318 if (state == NULL)
319 return NULL;
320
321 state->w_size = w_size;
322 state->strm.next_out = NULL;
323 state->strm.workspace = vmalloc(zlib_inflate_workspacesize());
324 if (state->strm.workspace == NULL)
325 goto out_free;
326
327 if (zlib_inflateInit2(&state->strm, -w_size) != Z_OK)
328 goto out_free;
329 return (void *) state;
330
331out_free:
332 z_decomp_free(state);
333 return NULL;
334}
335
336/**
337 * z_decomp_init - initialize a previously-allocated decompressor.
338 * @arg: pointer to the private state for the decompressor
339 * @options: pointer to the CCP option data describing the
340 * compression that was negotiated with the peer
341 * @opt_len: length of the CCP option data at @options
342 * @unit: PPP unit number for diagnostic messages
343 * @hdrlen: ignored (present for backwards compatibility)
344 * @mru: maximum length of decompressed packets
345 * @debug: debug flag; if non-zero, debug messages are printed.
346 *
347 * The CCP options described by @options must match the options
348 * specified when the decompressor was allocated. The decompressor
349 * history is reset. Returns 0 for failure (CCP options don't
350 * match) or 1 for success.
351 */
352static int z_decomp_init(void *arg, unsigned char *options, int opt_len,
353 int unit, int hdrlen, int mru, int debug)
354{
355 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
356
357 if (opt_len < CILEN_DEFLATE ||
358 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
359 options[1] != CILEN_DEFLATE ||
360 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
361 DEFLATE_SIZE(options[2]) != state->w_size ||
362 options[3] != DEFLATE_CHK_SEQUENCE)
363 return 0;
364
365 state->seqno = 0;
366 state->unit = unit;
367 state->debug = debug;
368 state->mru = mru;
369
370 zlib_inflateReset(&state->strm);
371
372 return 1;
373}
374
375/**
376 * z_decomp_reset - reset a previously-allocated decompressor.
377 * @arg: pointer to private state for the decompressor.
378 *
379 * This clears the history for the decompressor and makes it
380 * ready to receive a new compressed stream.
381 */
382static void z_decomp_reset(void *arg)
383{
384 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
385
386 state->seqno = 0;
387 zlib_inflateReset(&state->strm);
388}
389
390/**
391 * z_decompress - decompress a Deflate-compressed packet.
392 * @arg: pointer to private state for the decompressor
393 * @ibuf: pointer to input (compressed) packet data
394 * @isize: length of input packet
395 * @obuf: pointer to space for output (decompressed) packet
396 * @osize: amount of space available at @obuf
397 *
398 * Because of patent problems, we return DECOMP_ERROR for errors
399 * found by inspecting the input data and for system problems, but
400 * DECOMP_FATALERROR for any errors which could possibly be said to
401 * be being detected "after" decompression. For DECOMP_ERROR,
402 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
403 * infringing a patent of Motorola's if we do, so we take CCP down
404 * instead.
405 *
406 * Given that the frame has the correct sequence number and a good FCS,
407 * errors such as invalid codes in the input most likely indicate a
408 * bug, so we return DECOMP_FATALERROR for them in order to turn off
409 * compression, even though they are detected by inspecting the input.
410 */
411static int z_decompress(void *arg, unsigned char *ibuf, int isize,
412 unsigned char *obuf, int osize)
413{
414 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
415 int olen, seq, r;
416 int decode_proto, overflow;
417 unsigned char overflow_buf[1];
418
419 if (isize <= PPP_HDRLEN + DEFLATE_OVHD) {
420 if (state->debug)
421 printk(KERN_DEBUG "z_decompress%d: short pkt (%d)\n",
422 state->unit, isize);
423 return DECOMP_ERROR;
424 }
425
426 /* Check the sequence number. */
427 seq = get_unaligned_be16(ibuf + PPP_HDRLEN);
428 if (seq != (state->seqno & 0xffff)) {
429 if (state->debug)
430 printk(KERN_DEBUG "z_decompress%d: bad seq # %d, expected %d\n",
431 state->unit, seq, state->seqno & 0xffff);
432 return DECOMP_ERROR;
433 }
434 ++state->seqno;
435
436 /*
437 * Fill in the first part of the PPP header. The protocol field
438 * comes from the decompressed data.
439 */
440 obuf[0] = PPP_ADDRESS(ibuf);
441 obuf[1] = PPP_CONTROL(ibuf);
442 obuf[2] = 0;
443
444 /*
445 * Set up to call inflate. We set avail_out to 1 initially so we can
446 * look at the first byte of the output and decide whether we have
447 * a 1-byte or 2-byte protocol field.
448 */
449 state->strm.next_in = ibuf + PPP_HDRLEN + DEFLATE_OVHD;
450 state->strm.avail_in = isize - (PPP_HDRLEN + DEFLATE_OVHD);
451 state->strm.next_out = obuf + 3;
452 state->strm.avail_out = 1;
453 decode_proto = 1;
454 overflow = 0;
455
456 /*
457 * Call inflate, supplying more input or output as needed.
458 */
459 for (;;) {
460 r = zlib_inflate(&state->strm, Z_PACKET_FLUSH);
461 if (r != Z_OK) {
462 if (state->debug)
463 printk(KERN_DEBUG "z_decompress%d: inflate returned %d (%s)\n",
464 state->unit, r, (state->strm.msg? state->strm.msg: ""));
465 return DECOMP_FATALERROR;
466 }
467 if (state->strm.avail_out != 0)
468 break; /* all done */
469 if (decode_proto) {
470 state->strm.avail_out = osize - PPP_HDRLEN;
471 if ((obuf[3] & 1) == 0) {
472 /* 2-byte protocol field */
473 obuf[2] = obuf[3];
474 --state->strm.next_out;
475 ++state->strm.avail_out;
476 }
477 decode_proto = 0;
478 } else if (!overflow) {
479 /*
480 * We've filled up the output buffer; the only way to
481 * find out whether inflate has any more characters
482 * left is to give it another byte of output space.
483 */
484 state->strm.next_out = overflow_buf;
485 state->strm.avail_out = 1;
486 overflow = 1;
487 } else {
488 if (state->debug)
489 printk(KERN_DEBUG "z_decompress%d: ran out of mru\n",
490 state->unit);
491 return DECOMP_FATALERROR;
492 }
493 }
494
495 if (decode_proto) {
496 if (state->debug)
497 printk(KERN_DEBUG "z_decompress%d: didn't get proto\n",
498 state->unit);
499 return DECOMP_ERROR;
500 }
501
502 olen = osize + overflow - state->strm.avail_out;
503 state->stats.unc_bytes += olen;
504 state->stats.unc_packets++;
505 state->stats.comp_bytes += isize;
506 state->stats.comp_packets++;
507
508 return olen;
509}
510
511/**
512 * z_incomp - add incompressible input data to the history.
513 * @arg: pointer to private state for the decompressor
514 * @ibuf: pointer to input packet data
515 * @icnt: length of input data.
516 */
517static void z_incomp(void *arg, unsigned char *ibuf, int icnt)
518{
519 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
520 int proto, r;
521
522 /*
523 * Check that the protocol is one we handle.
524 */
525 proto = PPP_PROTOCOL(ibuf);
526 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
527 return;
528
529 ++state->seqno;
530
531 /*
532 * We start at the either the 1st or 2nd byte of the protocol field,
533 * depending on whether the protocol value is compressible.
534 */
535 state->strm.next_in = ibuf + 3;
536 state->strm.avail_in = icnt - 3;
537 if (proto > 0xff) {
538 --state->strm.next_in;
539 ++state->strm.avail_in;
540 }
541
542 r = zlib_inflateIncomp(&state->strm);
543 if (r != Z_OK) {
544 /* gak! */
545 if (state->debug) {
546 printk(KERN_DEBUG "z_incomp%d: inflateIncomp returned %d (%s)\n",
547 state->unit, r, (state->strm.msg? state->strm.msg: ""));
548 }
549 return;
550 }
551
552 /*
553 * Update stats.
554 */
555 state->stats.inc_bytes += icnt;
556 state->stats.inc_packets++;
557 state->stats.unc_bytes += icnt;
558 state->stats.unc_packets++;
559}
560
561/*************************************************************
562 * Module interface table
563 *************************************************************/
564
565/* These are in ppp_generic.c */
566extern int ppp_register_compressor (struct compressor *cp);
567extern void ppp_unregister_compressor (struct compressor *cp);
568
569/*
570 * Procedures exported to if_ppp.c.
571 */
572static struct compressor ppp_deflate = {
573 .compress_proto = CI_DEFLATE,
574 .comp_alloc = z_comp_alloc,
575 .comp_free = z_comp_free,
576 .comp_init = z_comp_init,
577 .comp_reset = z_comp_reset,
578 .compress = z_compress,
579 .comp_stat = z_comp_stats,
580 .decomp_alloc = z_decomp_alloc,
581 .decomp_free = z_decomp_free,
582 .decomp_init = z_decomp_init,
583 .decomp_reset = z_decomp_reset,
584 .decompress = z_decompress,
585 .incomp = z_incomp,
586 .decomp_stat = z_comp_stats,
587 .owner = THIS_MODULE
588};
589
590static struct compressor ppp_deflate_draft = {
591 .compress_proto = CI_DEFLATE_DRAFT,
592 .comp_alloc = z_comp_alloc,
593 .comp_free = z_comp_free,
594 .comp_init = z_comp_init,
595 .comp_reset = z_comp_reset,
596 .compress = z_compress,
597 .comp_stat = z_comp_stats,
598 .decomp_alloc = z_decomp_alloc,
599 .decomp_free = z_decomp_free,
600 .decomp_init = z_decomp_init,
601 .decomp_reset = z_decomp_reset,
602 .decompress = z_decompress,
603 .incomp = z_incomp,
604 .decomp_stat = z_comp_stats,
605 .owner = THIS_MODULE
606};
607
608static int __init deflate_init(void)
609{
610 int rc;
611
612 rc = ppp_register_compressor(&ppp_deflate);
613 if (rc)
614 return rc;
615
616 rc = ppp_register_compressor(&ppp_deflate_draft);
617 if (rc) {
618 ppp_unregister_compressor(&ppp_deflate);
619 return rc;
620 }
621
622 pr_info("PPP Deflate Compression module registered\n");
623 return 0;
624}
625
626static void __exit deflate_cleanup(void)
627{
628 ppp_unregister_compressor(&ppp_deflate);
629 ppp_unregister_compressor(&ppp_deflate_draft);
630}
631
632module_init(deflate_init);
633module_exit(deflate_cleanup);
634MODULE_LICENSE("Dual BSD/GPL");
635MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE));
636MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE_DRAFT));