2 * ==FILEVERSION 971001==
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/version.h>
36 #include <linux/kernel.h>
37 #include <linux/sched.h>
38 #include <linux/types.h>
39 #include <linux/fcntl.h>
40 #include <linux/interrupt.h>
41 #include <linux/ptrace.h>
42 #include <linux/ioport.h>
44 #include <linux/malloc.h>
47 /* a nice define to generate linux version numbers */
48 #define VERSION(major,minor,patch) (((((major)<<8)+(minor))<<8)+(patch))
50 #if LINUX_VERSION_CODE >= VERSION(2,1,4)
51 #include <linux/vmalloc.h>
54 #include <linux/errno.h>
55 #include <linux/sched.h> /* to get the struct task_struct */
56 #include <linux/string.h> /* used in new tty drivers */
57 #include <linux/signal.h> /* used in new tty drivers */
59 #include <asm/system.h>
61 #include <linux/netdevice.h>
62 #include <linux/skbuff.h>
63 #include <linux/inet.h>
64 #include <linux/ioctl.h>
66 #include <linux/ppp_defs.h>
67 #include <linux/ppp-comp.h>
72 * State for a Deflate (de)compressor.
74 struct ppp_deflate_state {
81 struct compstat stats;
84 #define DEFLATE_OVHD 2 /* Deflate overhead/packet */
86 static void *zalloc __P((void *, unsigned int items, unsigned int size));
87 static void *zalloc_init __P((void *, unsigned int items,
89 static void zfree __P((void *, void *ptr));
90 static void *z_comp_alloc __P((unsigned char *options, int opt_len));
91 static void *z_decomp_alloc __P((unsigned char *options, int opt_len));
92 static void z_comp_free __P((void *state));
93 static void z_decomp_free __P((void *state));
94 static int z_comp_init __P((void *state, unsigned char *options,
96 int unit, int hdrlen, int debug));
97 static int z_decomp_init __P((void *state, unsigned char *options,
99 int unit, int hdrlen, int mru, int debug));
100 static int z_compress __P((void *state, unsigned char *rptr,
102 int isize, int osize));
103 static void z_incomp __P((void *state, unsigned char *ibuf, int icnt));
104 static int z_decompress __P((void *state, unsigned char *ibuf,
105 int isize, unsigned char *obuf, int osize));
106 static void z_comp_reset __P((void *state));
107 static void z_decomp_reset __P((void *state));
108 static void z_comp_stats __P((void *state, struct compstat *stats));
110 struct chunk_header {
111 int valloced; /* allocated with valloc, not kmalloc */
112 int guard; /* check for overwritten header */
115 #define GUARD_MAGIC 0x77a8011a
116 #define MIN_VMALLOC 2048 /* use kmalloc for blocks < this */
119 * Space allocation and freeing routines for use by zlib routines.
126 struct chunk_header *hdr = ((struct chunk_header *)ptr) - 1;
128 if (hdr->guard != GUARD_MAGIC) {
129 printk(KERN_WARNING "zfree: header corrupted (%x %x) at %p\n",
130 hdr->valloced, hdr->guard, hdr);
140 zalloc(arg, items, size)
142 unsigned int items, size;
144 struct chunk_header *hdr;
147 nbytes = items * size + sizeof(*hdr);
148 hdr = kmalloc(nbytes, GFP_ATOMIC);
152 hdr->guard = GUARD_MAGIC;
153 return (void *) (hdr + 1);
157 zalloc_init(arg, items, size)
159 unsigned int items, size;
161 struct chunk_header *hdr;
164 nbytes = items * size + sizeof(*hdr);
165 if (nbytes >= MIN_VMALLOC)
166 hdr = vmalloc(nbytes);
168 hdr = kmalloc(nbytes, GFP_KERNEL);
171 hdr->valloced = nbytes >= MIN_VMALLOC;
172 hdr->guard = GUARD_MAGIC;
173 return (void *) (hdr + 1);
180 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
183 deflateEnd(&state->strm);
190 * Allocate space for a compressor.
193 z_comp_alloc(options, opt_len)
194 unsigned char *options;
197 struct ppp_deflate_state *state;
200 if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
201 || options[1] != CILEN_DEFLATE
202 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
203 || options[3] != DEFLATE_CHK_SEQUENCE)
205 w_size = DEFLATE_SIZE(options[2]);
206 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
209 state = (struct ppp_deflate_state *) kmalloc(sizeof(*state), GFP_KERNEL);
214 memset (state, 0, sizeof (struct ppp_deflate_state));
215 state->strm.next_in = NULL;
216 state->strm.zalloc = zalloc_init;
217 state->strm.zfree = zfree;
218 state->w_size = w_size;
220 if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION,
221 DEFLATE_METHOD_VAL, -w_size, 8, Z_DEFAULT_STRATEGY)
227 state->strm.zalloc = zalloc;
228 return (void *) state;
232 z_comp_init(arg, options, opt_len, unit, hdrlen, debug)
234 unsigned char *options;
235 int opt_len, unit, hdrlen, debug;
237 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
239 if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
240 || options[1] != CILEN_DEFLATE
241 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
242 || DEFLATE_SIZE(options[2]) != state->w_size
243 || options[3] != DEFLATE_CHK_SEQUENCE)
248 state->debug = debug;
250 deflateReset(&state->strm);
259 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
262 deflateReset(&state->strm);
266 z_compress(arg, rptr, obuf, isize, osize)
268 unsigned char *rptr; /* uncompressed packet (in) */
269 unsigned char *obuf; /* compressed packet (out) */
272 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
273 int r, proto, off, olen;
277 * Check that the protocol is in the range we handle.
279 proto = PPP_PROTOCOL(rptr);
280 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
283 /* Don't generate compressed packets which are larger than
284 the uncompressed packet. */
291 * Copy over the PPP header and store the 2-byte sequence number.
293 wptr[0] = PPP_ADDRESS(rptr);
294 wptr[1] = PPP_CONTROL(rptr);
295 wptr[2] = PPP_COMP >> 8;
298 wptr[0] = state->seqno >> 8;
299 wptr[1] = state->seqno;
301 state->strm.next_out = wptr;
302 state->strm.avail_out = osize - (PPP_HDRLEN + 2);
305 off = (proto > 0xff) ? 2 : 3; /* skip 1st proto byte if 0 */
307 state->strm.next_in = rptr;
308 state->strm.avail_in = (isize - off);
312 r = deflate(&state->strm, Z_PACKET_FLUSH);
315 printk(KERN_DEBUG "z_compress: deflate returned %d (%s)\n",
316 r, (state->strm.msg? state->strm.msg: ""));
319 if (state->strm.avail_out == 0) {
321 state->strm.next_out = NULL;
322 state->strm.avail_out = 1000000;
324 break; /* all done */
328 olen += osize - state->strm.avail_out;
331 * See if we managed to reduce the size of the packet.
334 state->stats.comp_bytes += olen;
335 state->stats.comp_packets++;
337 state->stats.inc_bytes += isize;
338 state->stats.inc_packets++;
341 state->stats.unc_bytes += isize;
342 state->stats.unc_packets++;
348 z_comp_stats(arg, stats)
350 struct compstat *stats;
352 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
354 *stats = state->stats;
361 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
364 inflateEnd(&state->strm);
371 * Allocate space for a decompressor.
374 z_decomp_alloc(options, opt_len)
375 unsigned char *options;
378 struct ppp_deflate_state *state;
381 if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
382 || options[1] != CILEN_DEFLATE
383 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
384 || options[3] != DEFLATE_CHK_SEQUENCE)
386 w_size = DEFLATE_SIZE(options[2]);
387 if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
390 state = (struct ppp_deflate_state *) kmalloc(sizeof(*state), GFP_KERNEL);
395 memset (state, 0, sizeof (struct ppp_deflate_state));
396 state->w_size = w_size;
397 state->strm.next_out = NULL;
398 state->strm.zalloc = zalloc_init;
399 state->strm.zfree = zfree;
401 if (inflateInit2(&state->strm, -w_size) != Z_OK) {
402 z_decomp_free(state);
406 state->strm.zalloc = zalloc;
407 return (void *) state;
411 z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
413 unsigned char *options;
414 int opt_len, unit, hdrlen, mru, debug;
416 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
418 if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
419 || options[1] != CILEN_DEFLATE
420 || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
421 || DEFLATE_SIZE(options[2]) != state->w_size
422 || options[3] != DEFLATE_CHK_SEQUENCE)
427 state->debug = debug;
430 inflateReset(&state->strm);
439 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
442 inflateReset(&state->strm);
446 * Decompress a Deflate-compressed packet.
448 * Because of patent problems, we return DECOMP_ERROR for errors
449 * found by inspecting the input data and for system problems, but
450 * DECOMP_FATALERROR for any errors which could possibly be said to
451 * be being detected "after" decompression. For DECOMP_ERROR,
452 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
453 * infringing a patent of Motorola's if we do, so we take CCP down
456 * Given that the frame has the correct sequence number and a good FCS,
457 * errors such as invalid codes in the input most likely indicate a
458 * bug, so we return DECOMP_FATALERROR for them in order to turn off
459 * compression, even though they are detected by inspecting the input.
462 z_decompress(arg, ibuf, isize, obuf, osize)
469 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
471 int decode_proto, overflow;
472 unsigned char overflow_buf[1];
474 if (isize <= PPP_HDRLEN + DEFLATE_OVHD) {
476 printk(KERN_DEBUG "z_decompress%d: short pkt (%d)\n",
481 /* Check the sequence number. */
482 seq = (ibuf[PPP_HDRLEN] << 8) + ibuf[PPP_HDRLEN+1];
483 if (seq != state->seqno) {
485 printk(KERN_DEBUG "z_decompress%d: bad seq # %d, expected %d\n",
486 state->unit, seq, state->seqno);
492 * Fill in the first part of the PPP header. The protocol field
493 * comes from the decompressed data.
495 obuf[0] = PPP_ADDRESS(ibuf);
496 obuf[1] = PPP_CONTROL(ibuf);
500 * Set up to call inflate. We set avail_out to 1 initially so we can
501 * look at the first byte of the output and decide whether we have
502 * a 1-byte or 2-byte protocol field.
504 state->strm.next_in = ibuf + PPP_HDRLEN + DEFLATE_OVHD;
505 state->strm.avail_in = isize - (PPP_HDRLEN + DEFLATE_OVHD);
506 state->strm.next_out = obuf + 3;
507 state->strm.avail_out = 1;
512 * Call inflate, supplying more input or output as needed.
515 r = inflate(&state->strm, Z_PACKET_FLUSH);
518 printk(KERN_DEBUG "z_decompress%d: inflate returned %d (%s)\n",
519 state->unit, r, (state->strm.msg? state->strm.msg: ""));
520 return DECOMP_FATALERROR;
522 if (state->strm.avail_out != 0)
523 break; /* all done */
525 state->strm.avail_out = osize - PPP_HDRLEN;
526 if ((obuf[3] & 1) == 0) {
527 /* 2-byte protocol field */
529 --state->strm.next_out;
530 ++state->strm.avail_out;
533 } else if (!overflow) {
535 * We've filled up the output buffer; the only way to
536 * find out whether inflate has any more characters
537 * left is to give it another byte of output space.
539 state->strm.next_out = overflow_buf;
540 state->strm.avail_out = 1;
544 printk(KERN_DEBUG "z_decompress%d: ran out of mru\n",
546 return DECOMP_FATALERROR;
553 olen = osize + overflow - state->strm.avail_out;
554 state->stats.unc_bytes += olen;
555 state->stats.unc_packets++;
556 state->stats.comp_bytes += isize;
557 state->stats.comp_packets++;
563 * Incompressible data has arrived - add it to the history.
566 z_incomp(arg, ibuf, icnt)
571 struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
575 * Check that the protocol is one we handle.
577 proto = PPP_PROTOCOL(ibuf);
578 if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
584 * We start at the either the 1st or 2nd byte of the protocol field,
585 * depending on whether the protocol value is compressible.
587 state->strm.next_in = ibuf + 3;
588 state->strm.avail_in = icnt - 3;
590 --state->strm.next_in;
591 ++state->strm.avail_in;
594 r = inflateIncomp(&state->strm);
598 printk(KERN_DEBUG "z_incomp%d: inflateIncomp returned %d (%s)\n",
599 state->unit, r, (state->strm.msg? state->strm.msg: ""));
607 state->stats.inc_bytes += icnt;
608 state->stats.inc_packets++;
609 state->stats.unc_bytes += icnt;
610 state->stats.unc_packets++;
613 /*************************************************************
614 * Module interface table
615 *************************************************************/
617 /* These are in ppp.c */
618 extern int ppp_register_compressor (struct compressor *cp);
619 extern void ppp_unregister_compressor (struct compressor *cp);
622 * Procedures exported to if_ppp.c.
624 struct compressor ppp_deflate = {
625 CI_DEFLATE, /* compress_proto */
626 z_comp_alloc, /* comp_alloc */
627 z_comp_free, /* comp_free */
628 z_comp_init, /* comp_init */
629 z_comp_reset, /* comp_reset */
630 z_compress, /* compress */
631 z_comp_stats, /* comp_stat */
632 z_decomp_alloc, /* decomp_alloc */
633 z_decomp_free, /* decomp_free */
634 z_decomp_init, /* decomp_init */
635 z_decomp_reset, /* decomp_reset */
636 z_decompress, /* decompress */
637 z_incomp, /* incomp */
638 z_comp_stats, /* decomp_stat */
642 /*************************************************************
643 * Module support routines
644 *************************************************************/
649 int answer = ppp_register_compressor (&ppp_deflate);
652 "PPP Deflate Compression module registered\n");
661 "Deflate Compression module busy, remove delayed\n");
663 ppp_unregister_compressor (&ppp_deflate);