2 * ==FILEVERSION 980319==
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 Linux kernel 1.3.X.
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,
31 * From: deflate.c,v 1.1 1996/01/18 03:17:48 paulus Exp
34 #include <linux/module.h>
35 #include <linux/slab.h>
36 #include <linux/vmalloc.h>
37 #include <linux/init.h>
38 #include <linux/string.h>
40 #include <linux/ppp_defs.h>
41 #include <linux/ppp-comp.h>
43 #include <linux/zlib.h>
44 #include <asm/unaligned.h>
47 * State for a Deflate (de)compressor.
49 struct ppp_deflate_state {
56 struct compstat stats;
59 #define DEFLATE_OVHD 2 /* Deflate overhead/packet */
61 static void *z_comp_alloc(unsigned char *options, int opt_len);
62 static void *z_decomp_alloc(unsigned char *options, int opt_len);
63 static void z_comp_free(void *state);
64 static void z_decomp_free(void *state);
65 static int z_comp_init(void *state, unsigned char *options,
67 int unit, int hdrlen, int debug);
68 static int z_decomp_init(void *state, unsigned char *options,
70 int unit, int hdrlen, int mru, int debug);
71 static int z_compress(void *state, unsigned char *rptr,
73 int isize, int osize);
74 static void z_incomp(void *state, unsigned char *ibuf, int icnt);
75 static int z_decompress(void *state, unsigned char *ibuf,
76 int isize, unsigned char *obuf, int osize);
77 static void z_comp_reset(void *state);
78 static void z_decomp_reset(void *state);
79 static void z_comp_stats(void *state, struct compstat *stats);
82 * z_comp_free - free the memory used by a compressor
83 * @arg: pointer to the private state for the compressor.
85 static void z_comp_free(void *arg)
87 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
90 zlib_deflateEnd(&state->strm);
91 vfree(state->strm.workspace);
97 * z_comp_alloc - allocate space for a compressor.
98 * @options: pointer to CCP option data
99 * @opt_len: length of the CCP option at @options.
101 * The @options pointer points to the a buffer containing the
102 * CCP option data for the compression being negotiated. It is
103 * formatted according to RFC1979, and describes the window
104 * size that the peer is requesting that we use in compressing
105 * data to be sent to it.
107 * Returns the pointer to the private state for the compressor,
108 * or NULL if we could not allocate enough memory.
110 static void *z_comp_alloc(unsigned char *options, int opt_len)
112 struct ppp_deflate_state *state;
115 if (opt_len != CILEN_DEFLATE ||
116 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
117 options[1] != CILEN_DEFLATE ||
118 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
119 options[3] != DEFLATE_CHK_SEQUENCE)
121 w_size = DEFLATE_SIZE(options[2]);
122 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
125 state = kzalloc(sizeof(*state),
130 state->strm.next_in = NULL;
131 state->w_size = w_size;
132 state->strm.workspace = vmalloc(zlib_deflate_workspacesize(-w_size, 8));
133 if (state->strm.workspace == NULL)
136 if (zlib_deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION,
137 DEFLATE_METHOD_VAL, -w_size, 8, Z_DEFAULT_STRATEGY)
140 return (void *) state;
148 * z_comp_init - initialize a previously-allocated compressor.
149 * @arg: pointer to the private state for the compressor
150 * @options: pointer to the CCP option data describing the
151 * compression that was negotiated with the peer
152 * @opt_len: length of the CCP option data at @options
153 * @unit: PPP unit number for diagnostic messages
154 * @hdrlen: ignored (present for backwards compatibility)
155 * @debug: debug flag; if non-zero, debug messages are printed.
157 * The CCP options described by @options must match the options
158 * specified when the compressor was allocated. The compressor
159 * history is reset. Returns 0 for failure (CCP options don't
160 * match) or 1 for success.
162 static int z_comp_init(void *arg, unsigned char *options, int opt_len,
163 int unit, int hdrlen, int debug)
165 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
167 if (opt_len < CILEN_DEFLATE ||
168 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
169 options[1] != CILEN_DEFLATE ||
170 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
171 DEFLATE_SIZE(options[2]) != state->w_size ||
172 options[3] != DEFLATE_CHK_SEQUENCE)
177 state->debug = debug;
179 zlib_deflateReset(&state->strm);
185 * z_comp_reset - reset a previously-allocated compressor.
186 * @arg: pointer to private state for the compressor.
188 * This clears the history for the compressor and makes it
189 * ready to start emitting a new compressed stream.
191 static void z_comp_reset(void *arg)
193 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
196 zlib_deflateReset(&state->strm);
200 * z_compress - compress a PPP packet with Deflate compression.
201 * @arg: pointer to private state for the compressor
202 * @rptr: uncompressed packet (input)
203 * @obuf: compressed packet (output)
204 * @isize: size of uncompressed packet
205 * @osize: space available at @obuf
207 * Returns the length of the compressed packet, or 0 if the
208 * packet is incompressible.
210 static int z_compress(void *arg, unsigned char *rptr, unsigned char *obuf,
211 int isize, int osize)
213 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
214 int r, proto, off, olen, oavail;
218 * Check that the protocol is in the range we handle.
220 proto = PPP_PROTOCOL(rptr);
221 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
224 /* Don't generate compressed packets which are larger than
225 the uncompressed packet. */
232 * Copy over the PPP header and store the 2-byte sequence number.
234 wptr[0] = PPP_ADDRESS(rptr);
235 wptr[1] = PPP_CONTROL(rptr);
236 put_unaligned_be16(PPP_COMP, wptr + 2);
238 put_unaligned_be16(state->seqno, wptr);
239 wptr += DEFLATE_OVHD;
240 olen = PPP_HDRLEN + DEFLATE_OVHD;
241 state->strm.next_out = wptr;
242 state->strm.avail_out = oavail = osize - olen;
245 off = (proto > 0xff) ? 2 : 3; /* skip 1st proto byte if 0 */
247 state->strm.next_in = rptr;
248 state->strm.avail_in = (isize - off);
251 r = zlib_deflate(&state->strm, Z_PACKET_FLUSH);
255 "z_compress: deflate returned %d\n", r);
258 if (state->strm.avail_out == 0) {
260 state->strm.next_out = NULL;
261 state->strm.avail_out = oavail = 1000000;
263 break; /* all done */
266 olen += oavail - state->strm.avail_out;
269 * See if we managed to reduce the size of the packet.
272 state->stats.comp_bytes += olen;
273 state->stats.comp_packets++;
275 state->stats.inc_bytes += isize;
276 state->stats.inc_packets++;
279 state->stats.unc_bytes += isize;
280 state->stats.unc_packets++;
286 * z_comp_stats - return compression statistics for a compressor
288 * @arg: pointer to private space for the (de)compressor
289 * @stats: pointer to a struct compstat to receive the result.
291 static void z_comp_stats(void *arg, struct compstat *stats)
293 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
295 *stats = state->stats;
299 * z_decomp_free - Free the memory used by a decompressor.
300 * @arg: pointer to private space for the decompressor.
302 static void z_decomp_free(void *arg)
304 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
307 zlib_inflateEnd(&state->strm);
308 kfree(state->strm.workspace);
314 * z_decomp_alloc - allocate space for a decompressor.
315 * @options: pointer to CCP option data
316 * @opt_len: length of the CCP option at @options.
318 * The @options pointer points to the a buffer containing the
319 * CCP option data for the compression being negotiated. It is
320 * formatted according to RFC1979, and describes the window
321 * size that we are requesting the peer to use in compressing
322 * data to be sent to us.
324 * Returns the pointer to the private state for the decompressor,
325 * or NULL if we could not allocate enough memory.
327 static void *z_decomp_alloc(unsigned char *options, int opt_len)
329 struct ppp_deflate_state *state;
332 if (opt_len != CILEN_DEFLATE ||
333 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
334 options[1] != CILEN_DEFLATE ||
335 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
336 options[3] != DEFLATE_CHK_SEQUENCE)
338 w_size = DEFLATE_SIZE(options[2]);
339 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
342 state = kzalloc(sizeof(*state), GFP_KERNEL);
346 state->w_size = w_size;
347 state->strm.next_out = NULL;
348 state->strm.workspace = kmalloc(zlib_inflate_workspacesize(),
349 GFP_KERNEL|__GFP_REPEAT);
350 if (state->strm.workspace == NULL)
353 if (zlib_inflateInit2(&state->strm, -w_size) != Z_OK)
355 return (void *) state;
358 z_decomp_free(state);
363 * z_decomp_init - initialize a previously-allocated decompressor.
364 * @arg: pointer to the private state for the decompressor
365 * @options: pointer to the CCP option data describing the
366 * compression that was negotiated with the peer
367 * @opt_len: length of the CCP option data at @options
368 * @unit: PPP unit number for diagnostic messages
369 * @hdrlen: ignored (present for backwards compatibility)
370 * @mru: maximum length of decompressed packets
371 * @debug: debug flag; if non-zero, debug messages are printed.
373 * The CCP options described by @options must match the options
374 * specified when the decompressor was allocated. The decompressor
375 * history is reset. Returns 0 for failure (CCP options don't
376 * match) or 1 for success.
378 static int z_decomp_init(void *arg, unsigned char *options, int opt_len,
379 int unit, int hdrlen, int mru, int debug)
381 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
383 if (opt_len < CILEN_DEFLATE ||
384 (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
385 options[1] != CILEN_DEFLATE ||
386 DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
387 DEFLATE_SIZE(options[2]) != state->w_size ||
388 options[3] != DEFLATE_CHK_SEQUENCE)
393 state->debug = debug;
396 zlib_inflateReset(&state->strm);
402 * z_decomp_reset - reset a previously-allocated decompressor.
403 * @arg: pointer to private state for the decompressor.
405 * This clears the history for the decompressor and makes it
406 * ready to receive a new compressed stream.
408 static void z_decomp_reset(void *arg)
410 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
413 zlib_inflateReset(&state->strm);
417 * z_decompress - decompress a Deflate-compressed packet.
418 * @arg: pointer to private state for the decompressor
419 * @ibuf: pointer to input (compressed) packet data
420 * @isize: length of input packet
421 * @obuf: pointer to space for output (decompressed) packet
422 * @osize: amount of space available at @obuf
424 * Because of patent problems, we return DECOMP_ERROR for errors
425 * found by inspecting the input data and for system problems, but
426 * DECOMP_FATALERROR for any errors which could possibly be said to
427 * be being detected "after" decompression. For DECOMP_ERROR,
428 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
429 * infringing a patent of Motorola's if we do, so we take CCP down
432 * Given that the frame has the correct sequence number and a good FCS,
433 * errors such as invalid codes in the input most likely indicate a
434 * bug, so we return DECOMP_FATALERROR for them in order to turn off
435 * compression, even though they are detected by inspecting the input.
437 static int z_decompress(void *arg, unsigned char *ibuf, int isize,
438 unsigned char *obuf, int osize)
440 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
442 int decode_proto, overflow;
443 unsigned char overflow_buf[1];
445 if (isize <= PPP_HDRLEN + DEFLATE_OVHD) {
447 printk(KERN_DEBUG "z_decompress%d: short pkt (%d)\n",
452 /* Check the sequence number. */
453 seq = get_unaligned_be16(ibuf + PPP_HDRLEN);
454 if (seq != (state->seqno & 0xffff)) {
456 printk(KERN_DEBUG "z_decompress%d: bad seq # %d, expected %d\n",
457 state->unit, seq, state->seqno & 0xffff);
463 * Fill in the first part of the PPP header. The protocol field
464 * comes from the decompressed data.
466 obuf[0] = PPP_ADDRESS(ibuf);
467 obuf[1] = PPP_CONTROL(ibuf);
471 * Set up to call inflate. We set avail_out to 1 initially so we can
472 * look at the first byte of the output and decide whether we have
473 * a 1-byte or 2-byte protocol field.
475 state->strm.next_in = ibuf + PPP_HDRLEN + DEFLATE_OVHD;
476 state->strm.avail_in = isize - (PPP_HDRLEN + DEFLATE_OVHD);
477 state->strm.next_out = obuf + 3;
478 state->strm.avail_out = 1;
483 * Call inflate, supplying more input or output as needed.
486 r = zlib_inflate(&state->strm, Z_PACKET_FLUSH);
489 printk(KERN_DEBUG "z_decompress%d: inflate returned %d (%s)\n",
490 state->unit, r, (state->strm.msg? state->strm.msg: ""));
491 return DECOMP_FATALERROR;
493 if (state->strm.avail_out != 0)
494 break; /* all done */
496 state->strm.avail_out = osize - PPP_HDRLEN;
497 if ((obuf[3] & 1) == 0) {
498 /* 2-byte protocol field */
500 --state->strm.next_out;
501 ++state->strm.avail_out;
504 } else if (!overflow) {
506 * We've filled up the output buffer; the only way to
507 * find out whether inflate has any more characters
508 * left is to give it another byte of output space.
510 state->strm.next_out = overflow_buf;
511 state->strm.avail_out = 1;
515 printk(KERN_DEBUG "z_decompress%d: ran out of mru\n",
517 return DECOMP_FATALERROR;
523 printk(KERN_DEBUG "z_decompress%d: didn't get proto\n",
528 olen = osize + overflow - state->strm.avail_out;
529 state->stats.unc_bytes += olen;
530 state->stats.unc_packets++;
531 state->stats.comp_bytes += isize;
532 state->stats.comp_packets++;
538 * z_incomp - add incompressible input data to the history.
539 * @arg: pointer to private state for the decompressor
540 * @ibuf: pointer to input packet data
541 * @icnt: length of input data.
543 static void z_incomp(void *arg, unsigned char *ibuf, int icnt)
545 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
549 * Check that the protocol is one we handle.
551 proto = PPP_PROTOCOL(ibuf);
552 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
558 * We start at the either the 1st or 2nd byte of the protocol field,
559 * depending on whether the protocol value is compressible.
561 state->strm.next_in = ibuf + 3;
562 state->strm.avail_in = icnt - 3;
564 --state->strm.next_in;
565 ++state->strm.avail_in;
568 r = zlib_inflateIncomp(&state->strm);
572 printk(KERN_DEBUG "z_incomp%d: inflateIncomp returned %d (%s)\n",
573 state->unit, r, (state->strm.msg? state->strm.msg: ""));
581 state->stats.inc_bytes += icnt;
582 state->stats.inc_packets++;
583 state->stats.unc_bytes += icnt;
584 state->stats.unc_packets++;
587 /*************************************************************
588 * Module interface table
589 *************************************************************/
591 /* These are in ppp_generic.c */
592 extern int ppp_register_compressor (struct compressor *cp);
593 extern void ppp_unregister_compressor (struct compressor *cp);
596 * Procedures exported to if_ppp.c.
598 static struct compressor ppp_deflate = {
599 .compress_proto = CI_DEFLATE,
600 .comp_alloc = z_comp_alloc,
601 .comp_free = z_comp_free,
602 .comp_init = z_comp_init,
603 .comp_reset = z_comp_reset,
604 .compress = z_compress,
605 .comp_stat = z_comp_stats,
606 .decomp_alloc = z_decomp_alloc,
607 .decomp_free = z_decomp_free,
608 .decomp_init = z_decomp_init,
609 .decomp_reset = z_decomp_reset,
610 .decompress = z_decompress,
612 .decomp_stat = z_comp_stats,
616 static struct compressor ppp_deflate_draft = {
617 .compress_proto = CI_DEFLATE_DRAFT,
618 .comp_alloc = z_comp_alloc,
619 .comp_free = z_comp_free,
620 .comp_init = z_comp_init,
621 .comp_reset = z_comp_reset,
622 .compress = z_compress,
623 .comp_stat = z_comp_stats,
624 .decomp_alloc = z_decomp_alloc,
625 .decomp_free = z_decomp_free,
626 .decomp_init = z_decomp_init,
627 .decomp_reset = z_decomp_reset,
628 .decompress = z_decompress,
630 .decomp_stat = z_comp_stats,
634 static int __init deflate_init(void)
636 int answer = ppp_register_compressor(&ppp_deflate);
639 "PPP Deflate Compression module registered\n");
640 ppp_register_compressor(&ppp_deflate_draft);
644 static void __exit deflate_cleanup(void)
646 ppp_unregister_compressor(&ppp_deflate);
647 ppp_unregister_compressor(&ppp_deflate_draft);
650 module_init(deflate_init);
651 module_exit(deflate_cleanup);
652 MODULE_LICENSE("Dual BSD/GPL");
653 MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE));
654 MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE_DRAFT));