2 * Update: The Berkeley copyright was changed, and the change
3 * is retroactive to all "true" BSD software (ie everything
4 * from UCB as opposed to other peoples code that just carried
5 * the same license). The new copyright doesn't clash with the
6 * GPL, so the module-only restriction has been removed..
9 /* Because this code is derived from the 4.3BSD compress source:
11 * Copyright (c) 1985, 1986 The Regents of the University of California.
12 * All rights reserved.
14 * This code is derived from software contributed to Berkeley by
15 * James A. Woods, derived from original work by Spencer Thomas
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
26 * 3. All advertising materials mentioning features or use of this software
27 * must display the following acknowledgement:
28 * This product includes software developed by the University of
29 * California, Berkeley and its contributors.
30 * 4. Neither the name of the University nor the names of its contributors
31 * may be used to endorse or promote products derived from this software
32 * without specific prior written permission.
34 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
35 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
36 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
37 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
38 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
39 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
40 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
41 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
42 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
43 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48 * This version is for use with contiguous buffers on Linux-derived systems.
50 * ==FILEVERSION 20000226==
52 * NOTE TO MAINTAINERS:
53 * If you modify this file at all, please set the number above to the
54 * date of the modification as YYMMDD (year month day).
55 * bsd_comp.c is shipped with a PPP distribution as well as with
56 * the kernel; if everyone increases the FILEVERSION number above,
57 * then scripts can do the right thing when deciding whether to
58 * install a new bsd_comp.c file. Don't change the format of that
59 * line otherwise, so the installation script can recognize it.
61 * From: bsd_comp.c,v 1.3 1994/12/08 01:59:58 paulus Exp
64 #include <linux/module.h>
65 #include <linux/init.h>
66 #include <linux/slab.h>
67 #include <linux/vmalloc.h>
68 #include <linux/string.h>
70 #include <linux/ppp_defs.h>
74 #include <linux/ppp-comp.h>
77 #include <asm/byteorder.h>
80 * PPP "BSD compress" compression
81 * The differences between this compression and the classic BSD LZW
82 * source are obvious from the requirement that the classic code worked
83 * with files while this handles arbitrarily long streams that
84 * are broken into packets. They are:
86 * When the code size expands, a block of junk is not emitted by
87 * the compressor and not expected by the decompressor.
89 * New codes are not necessarily assigned every time an old
90 * code is output by the compressor. This is because a packet
91 * end forces a code to be emitted, but does not imply that a
92 * new sequence has been seen.
94 * The compression ratio is checked at the first end of a packet
95 * after the appropriate gap. Besides simplifying and speeding
96 * things up, this makes it more likely that the transmitter
97 * and receiver will agree when the dictionary is cleared when
98 * compression is not going well.
102 * Macros to extract protocol version and number of bits
103 * from the third byte of the BSD Compress CCP configuration option.
106 #define BSD_VERSION(x) ((x) >> 5)
107 #define BSD_NBITS(x) ((x) & 0x1F)
109 #define BSD_CURRENT_VERSION 1
112 * A dictionary for doing BSD compress.
116 union { /* hash value */
119 #if defined(__LITTLE_ENDIAN) /* Little endian order */
120 unsigned short prefix; /* preceding code */
121 unsigned char suffix; /* last character of new code */
123 #elif defined(__BIG_ENDIAN) /* Big endian order */
125 unsigned char suffix; /* last character of new code */
126 unsigned short prefix; /* preceding code */
128 #error Endianness not defined...
132 unsigned short codem1; /* output of hash table -1 */
133 unsigned short cptr; /* map code to hash table entry */
137 int totlen; /* length of this structure */
138 unsigned int hsize; /* size of the hash table */
139 unsigned char hshift; /* used in hash function */
140 unsigned char n_bits; /* current bits/code */
141 unsigned char maxbits; /* maximum bits/code */
142 unsigned char debug; /* non-zero if debug desired */
143 unsigned char unit; /* ppp unit number */
144 unsigned short seqno; /* sequence # of next packet */
145 unsigned int mru; /* size of receive (decompress) bufr */
146 unsigned int maxmaxcode; /* largest valid code */
147 unsigned int max_ent; /* largest code in use */
148 unsigned int in_count; /* uncompressed bytes, aged */
149 unsigned int bytes_out; /* compressed bytes, aged */
150 unsigned int ratio; /* recent compression ratio */
151 unsigned int checkpoint; /* when to next check the ratio */
152 unsigned int clear_count; /* times dictionary cleared */
153 unsigned int incomp_count; /* incompressible packets */
154 unsigned int incomp_bytes; /* incompressible bytes */
155 unsigned int uncomp_count; /* uncompressed packets */
156 unsigned int uncomp_bytes; /* uncompressed bytes */
157 unsigned int comp_count; /* compressed packets */
158 unsigned int comp_bytes; /* compressed bytes */
159 unsigned short *lens; /* array of lengths of codes */
160 struct bsd_dict *dict; /* dictionary */
163 #define BSD_OVHD 2 /* BSD compress overhead/packet */
164 #define MIN_BSD_BITS 9
165 #define BSD_INIT_BITS MIN_BSD_BITS
166 #define MAX_BSD_BITS 15
168 static void bsd_free (void *state);
169 static void *bsd_alloc(unsigned char *options, int opt_len, int decomp);
170 static void *bsd_comp_alloc (unsigned char *options, int opt_len);
171 static void *bsd_decomp_alloc (unsigned char *options, int opt_len);
173 static int bsd_init (void *db, unsigned char *options,
174 int opt_len, int unit, int debug, int decomp);
175 static int bsd_comp_init (void *state, unsigned char *options,
176 int opt_len, int unit, int opthdr, int debug);
177 static int bsd_decomp_init (void *state, unsigned char *options,
178 int opt_len, int unit, int opthdr, int mru,
181 static void bsd_reset (void *state);
182 static void bsd_comp_stats (void *state, struct compstat *stats);
184 static int bsd_compress (void *state, unsigned char *rptr,
185 unsigned char *obuf, int isize, int osize);
186 static void bsd_incomp (void *state, unsigned char *ibuf, int icnt);
188 static int bsd_decompress (void *state, unsigned char *ibuf, int isize,
189 unsigned char *obuf, int osize);
191 /* These are in ppp_generic.c */
192 extern int ppp_register_compressor (struct compressor *cp);
193 extern void ppp_unregister_compressor (struct compressor *cp);
196 * the next two codes should not be changed lightly, as they must not
197 * lie within the contiguous general code space.
199 #define CLEAR 256 /* table clear output code */
200 #define FIRST 257 /* first free entry */
203 #define MAXCODE(b) ((1 << (b)) - 1)
204 #define BADCODEM1 MAXCODE(MAX_BSD_BITS);
206 #define BSD_HASH(prefix,suffix,hshift) ((((unsigned long)(suffix))<<(hshift)) \
207 ^ (unsigned long)(prefix))
208 #define BSD_KEY(prefix,suffix) ((((unsigned long)(suffix)) << 16) \
209 + (unsigned long)(prefix))
211 #define CHECK_GAP 10000 /* Ratio check interval */
213 #define RATIO_SCALE_LOG 8
214 #define RATIO_SCALE (1<<RATIO_SCALE_LOG)
215 #define RATIO_MAX (0x7fffffff>>RATIO_SCALE_LOG)
218 * clear the dictionary
222 bsd_clear(struct bsd_db *db)
225 db->max_ent = FIRST-1;
226 db->n_bits = BSD_INIT_BITS;
230 db->checkpoint = CHECK_GAP;
234 * If the dictionary is full, then see if it is time to reset it.
236 * Compute the compression ratio using fixed-point arithmetic
237 * with 8 fractional bits.
239 * Since we have an infinite stream instead of a single file,
240 * watch only the local compression ratio.
242 * Since both peers must reset the dictionary at the same time even in
243 * the absence of CLEAR codes (while packets are incompressible), they
244 * must compute the same ratio.
247 static int bsd_check (struct bsd_db *db) /* 1=output CLEAR */
249 unsigned int new_ratio;
251 if (db->in_count >= db->checkpoint)
253 /* age the ratio by limiting the size of the counts */
254 if (db->in_count >= RATIO_MAX || db->bytes_out >= RATIO_MAX)
256 db->in_count -= (db->in_count >> 2);
257 db->bytes_out -= (db->bytes_out >> 2);
260 db->checkpoint = db->in_count + CHECK_GAP;
262 if (db->max_ent >= db->maxmaxcode)
264 /* Reset the dictionary only if the ratio is worse,
265 * or if it looks as if it has been poisoned
266 * by incompressible data.
268 * This does not overflow, because
269 * db->in_count <= RATIO_MAX.
272 new_ratio = db->in_count << RATIO_SCALE_LOG;
273 if (db->bytes_out != 0)
275 new_ratio /= db->bytes_out;
278 if (new_ratio < db->ratio || new_ratio < 1 * RATIO_SCALE)
283 db->ratio = new_ratio;
293 static void bsd_comp_stats (void *state, struct compstat *stats)
295 struct bsd_db *db = (struct bsd_db *) state;
297 stats->unc_bytes = db->uncomp_bytes;
298 stats->unc_packets = db->uncomp_count;
299 stats->comp_bytes = db->comp_bytes;
300 stats->comp_packets = db->comp_count;
301 stats->inc_bytes = db->incomp_bytes;
302 stats->inc_packets = db->incomp_count;
303 stats->in_count = db->in_count;
304 stats->bytes_out = db->bytes_out;
308 * Reset state, as on a CCP ResetReq.
311 static void bsd_reset (void *state)
313 struct bsd_db *db = (struct bsd_db *) state;
322 * Release the compression structure
325 static void bsd_free (void *state)
327 struct bsd_db *db = state;
333 * Release the dictionary
338 * Release the string buffer
343 * Finally release the structure itself.
349 * Allocate space for a (de) compressor.
352 static void *bsd_alloc (unsigned char *options, int opt_len, int decomp)
355 unsigned int hsize, hshift, maxmaxcode;
358 if (opt_len != 3 || options[0] != CI_BSD_COMPRESS || options[1] != 3
359 || BSD_VERSION(options[2]) != BSD_CURRENT_VERSION)
364 bits = BSD_NBITS(options[2]);
368 case 9: /* needs 82152 for both directions */
369 case 10: /* needs 84144 */
370 case 11: /* needs 88240 */
371 case 12: /* needs 96432 */
375 case 13: /* needs 176784 */
379 case 14: /* needs 353744 */
383 case 15: /* needs 691440 */
387 case 16: /* needs 1366160--far too much, */
388 /* hsize = 69001; */ /* and 69001 is too big for cptr */
389 /* hshift = 8; */ /* in struct bsd_db */
395 * Allocate the main control structure for this instance.
397 maxmaxcode = MAXCODE(bits);
398 db = kzalloc(sizeof (struct bsd_db),
406 * Allocate space for the dictionary. This may be more than one page in
409 db->dict = (struct bsd_dict *) vmalloc (hsize *
410 sizeof (struct bsd_dict));
418 * If this is the compression buffer then there is no length data.
425 * For decompression, the length information is needed as well.
429 db->lens = (unsigned short *) vmalloc ((maxmaxcode + 1) *
430 sizeof (db->lens[0]));
438 * Initialize the data information for the compression code
440 db->totlen = sizeof (struct bsd_db) +
441 (sizeof (struct bsd_dict) * hsize);
445 db->maxmaxcode = maxmaxcode;
451 static void *bsd_comp_alloc (unsigned char *options, int opt_len)
453 return bsd_alloc (options, opt_len, 0);
456 static void *bsd_decomp_alloc (unsigned char *options, int opt_len)
458 return bsd_alloc (options, opt_len, 1);
462 * Initialize the database.
465 static int bsd_init (void *state, unsigned char *options,
466 int opt_len, int unit, int debug, int decomp)
468 struct bsd_db *db = state;
471 if ((opt_len != 3) || (options[0] != CI_BSD_COMPRESS) || (options[1] != 3)
472 || (BSD_VERSION(options[2]) != BSD_CURRENT_VERSION)
473 || (BSD_NBITS(options[2]) != db->maxbits)
474 || (decomp && db->lens == NULL))
492 db->dict[indx].codem1 = BADCODEM1;
493 db->dict[indx].cptr = 0;
508 static int bsd_comp_init (void *state, unsigned char *options,
509 int opt_len, int unit, int opthdr, int debug)
511 return bsd_init (state, options, opt_len, unit, debug, 0);
514 static int bsd_decomp_init (void *state, unsigned char *options,
515 int opt_len, int unit, int opthdr, int mru,
518 return bsd_init (state, options, opt_len, unit, debug, 1);
522 * Obtain pointers to the various structures in the compression tables
525 #define dict_ptrx(p,idx) &(p->dict[idx])
526 #define lens_ptrx(p,idx) &(p->lens[idx])
529 static unsigned short *lens_ptr(struct bsd_db *db, int idx)
531 if ((unsigned int) idx > (unsigned int) db->maxmaxcode)
533 printk ("<9>ppp: lens_ptr(%d) > max\n", idx);
536 return lens_ptrx (db, idx);
539 static struct bsd_dict *dict_ptr(struct bsd_db *db, int idx)
541 if ((unsigned int) idx >= (unsigned int) db->hsize)
543 printk ("<9>ppp: dict_ptr(%d) > max\n", idx);
546 return dict_ptrx (db, idx);
550 #define lens_ptr(db,idx) lens_ptrx(db,idx)
551 #define dict_ptr(db,idx) dict_ptrx(db,idx)
557 * The result of this function is the size of the compressed
558 * packet. A zero is returned if the packet was not compressed
559 * for some reason, such as the size being larger than uncompressed.
561 * One change from the BSD compress command is that when the
562 * code size expands, we do not output a bunch of padding.
565 static int bsd_compress (void *state, unsigned char *rptr, unsigned char *obuf,
566 int isize, int osize)
570 unsigned int max_ent;
576 struct bsd_dict *dictp;
590 *wptr++ = (unsigned char) (v); \
598 #define OUTPUT(ent) \
601 accm |= ((ent) << bitno); \
604 PUTBYTE(accm >> 24); \
608 while (bitno <= 24); \
612 * If the protocol is not in the range we're interested in,
613 * just return without compressing the packet. If it is,
614 * the protocol becomes the first byte to compress.
617 ent = PPP_PROTOCOL(rptr);
618 if (ent < 0x21 || ent > 0xf9)
623 db = (struct bsd_db *) state;
625 max_ent = db->max_ent;
629 mxcode = MAXCODE (n_bits);
631 /* Initialize the output pointers */
633 olen = PPP_HDRLEN + BSD_OVHD;
640 /* This is the PPP header information */
643 *wptr++ = PPP_ADDRESS(rptr);
644 *wptr++ = PPP_CONTROL(rptr);
647 *wptr++ = db->seqno >> 8;
651 /* Skip the input header */
654 ilen = ++isize; /* Low byte of protocol is counted as input */
659 fcode = BSD_KEY (ent, c);
660 hval = BSD_HASH (ent, c, hshift);
661 dictp = dict_ptr (db, hval);
663 /* Validate and then check the entry. */
664 if (dictp->codem1 >= max_ent)
669 if (dictp->f.fcode == fcode)
671 ent = dictp->codem1 + 1;
672 continue; /* found (prefix,suffix) */
675 /* continue probing until a match or invalid entry */
676 disp = (hval == 0) ? 1 : hval;
681 if (hval >= db->hsize)
685 dictp = dict_ptr (db, hval);
686 if (dictp->codem1 >= max_ent)
691 while (dictp->f.fcode != fcode);
693 ent = dictp->codem1 + 1; /* finally found (prefix,suffix) */
697 OUTPUT(ent); /* output the prefix */
699 /* code -> hashtable */
700 if (max_ent < db->maxmaxcode)
702 struct bsd_dict *dictp2;
703 struct bsd_dict *dictp3;
706 /* expand code size if needed */
707 if (max_ent >= mxcode)
709 db->n_bits = ++n_bits;
710 mxcode = MAXCODE (n_bits);
713 /* Invalidate old hash table entry using
714 * this code, and then take it over.
717 dictp2 = dict_ptr (db, max_ent + 1);
719 dictp3 = dict_ptr (db, indx);
721 if (dictp3->codem1 == max_ent)
723 dictp3->codem1 = BADCODEM1;
727 dictp->codem1 = max_ent;
728 dictp->f.fcode = fcode;
729 db->max_ent = ++max_ent;
733 unsigned short *len1 = lens_ptr (db, max_ent);
734 unsigned short *len2 = lens_ptr (db, ent);
741 OUTPUT(ent); /* output the last code */
743 db->bytes_out += olen - PPP_HDRLEN - BSD_OVHD;
744 db->uncomp_bytes += isize;
745 db->in_count += isize;
751 ++db->bytes_out; /* must be set before calling bsd_check */
755 * Generate the clear command if needed
764 * Pad dribble bits of last code with ones.
765 * Do not emit a completely useless byte of ones.
770 PUTBYTE((accm | (0xff << (bitno-8))) >> 24);
774 * Increase code size if we would have without the packet
775 * boundary because the decompressor will do so.
778 if (max_ent >= mxcode && max_ent < db->maxmaxcode)
783 /* If output length is too large then this is an incomplete frame. */
787 db->incomp_bytes += isize;
790 else /* Count the number of compressed frames */
793 db->comp_bytes += olen;
796 /* Return the resulting output length */
803 * Update the "BSD Compress" dictionary on the receiver for
804 * incompressible data by pretending to compress the incoming data.
807 static void bsd_incomp (void *state, unsigned char *ibuf, int icnt)
809 (void) bsd_compress (state, ibuf, (char *) 0, icnt, 0);
813 * Decompress "BSD Compress".
815 * Because of patent problems, we return DECOMP_ERROR for errors
816 * found by inspecting the input data and for system problems, but
817 * DECOMP_FATALERROR for any errors which could possibly be said to
818 * be being detected "after" decompression. For DECOMP_ERROR,
819 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
820 * infringing a patent of Motorola's if we do, so we take CCP down
823 * Given that the frame has the correct sequence number and a good FCS,
824 * errors such as invalid codes in the input most likely indicate a
825 * bug, so we return DECOMP_FATALERROR for them in order to turn off
826 * compression, even though they are detected by inspecting the input.
829 static int bsd_decompress (void *state, unsigned char *ibuf, int isize,
830 unsigned char *obuf, int osize)
833 unsigned int max_ent;
835 unsigned int bitno; /* 1st valid bit in accm */
837 unsigned int tgtbitno; /* bitno when we have a code */
838 struct bsd_dict *dictp;
842 unsigned int oldcode;
843 unsigned int finchar;
852 db = (struct bsd_db *) state;
853 max_ent = db->max_ent;
855 bitno = 32; /* 1st valid bit in accm */
857 tgtbitno = 32 - n_bits; /* bitno when we have a code */
860 * Save the address/control from the PPP header
861 * and then get the sequence number.
864 adrs = PPP_ADDRESS (ibuf);
865 ctrl = PPP_CONTROL (ibuf);
867 seq = (ibuf[4] << 8) + ibuf[5];
869 ibuf += (PPP_HDRLEN + 2);
870 ilen = isize - (PPP_HDRLEN + 2);
873 * Check the sequence number and give up if it differs from
874 * the value we're expecting.
877 if (seq != db->seqno)
881 printk("bsd_decomp%d: bad sequence # %d, expected %d\n",
882 db->unit, seq, db->seqno - 1);
888 db->bytes_out += ilen;
891 * Fill in the ppp header, but not the last byte of the protocol
892 * (that comes from the decompressed data).
904 * Keep the checkpoint correctly so that incompressible packets
905 * clear the dictionary at the proper times.
912 db->in_count += (explen - 3); /* don't count the header */
917 * Accumulate bytes until we have a complete code.
918 * Then get the next code, relying on the 32-bit,
919 * unsigned accm to mask the result.
923 accm |= *ibuf++ << bitno;
924 if (tgtbitno < bitno)
929 incode = accm >> tgtbitno;
934 * The dictionary must only be cleared at the end of a packet.
943 printk("bsd_decomp%d: bad CLEAR\n", db->unit);
945 return DECOMP_FATALERROR; /* probably a bug */
952 if ((incode > max_ent + 2) || (incode > db->maxmaxcode)
953 || (incode > max_ent && oldcode == CLEAR))
957 printk("bsd_decomp%d: bad code 0x%x oldcode=0x%x ",
958 db->unit, incode, oldcode);
959 printk("max_ent=0x%x explen=%d seqno=%d\n",
960 max_ent, explen, db->seqno);
962 return DECOMP_FATALERROR; /* probably a bug */
965 /* Special case for KwKwK string. */
966 if (incode > max_ent)
977 codelen = *(lens_ptr (db, finchar));
978 explen += codelen + extra;
983 printk("bsd_decomp%d: ran out of mru\n", db->unit);
985 printk(" len=%d, finchar=0x%x, codelen=%d, explen=%d\n",
986 ilen, finchar, codelen, explen);
989 return DECOMP_FATALERROR;
993 * Decode this code and install it in the decompressed buffer.
998 while (finchar > LAST)
1000 struct bsd_dict *dictp2 = dict_ptr (db, finchar);
1002 dictp = dict_ptr (db, dictp2->cptr);
1004 if (--codelen <= 0 || dictp->codem1 != finchar-1)
1008 printk("bsd_decomp%d: fell off end of chain ", db->unit);
1009 printk("0x%x at 0x%x by 0x%x, max_ent=0x%x\n",
1010 incode, finchar, dictp2->cptr, max_ent);
1014 if (dictp->codem1 != finchar-1)
1016 printk("bsd_decomp%d: bad code chain 0x%x "
1018 db->unit, incode, finchar);
1020 printk("oldcode=0x%x cptr=0x%x codem1=0x%x\n",
1021 oldcode, dictp2->cptr, dictp->codem1);
1024 return DECOMP_FATALERROR;
1027 *--p = dictp->f.hs.suffix;
1028 finchar = dictp->f.hs.prefix;
1035 printk("bsd_decomp%d: short by %d after code 0x%x, max_ent=0x%x\n",
1036 db->unit, codelen, incode, max_ent);
1040 if (extra) /* the KwKwK case again */
1046 * If not first code in a packet, and
1047 * if not out of code space, then allocate a new code.
1049 * Keep the hash table correct so it can be used
1050 * with uncompressed packets.
1053 if (oldcode != CLEAR && max_ent < db->maxmaxcode)
1055 struct bsd_dict *dictp2, *dictp3;
1056 unsigned short *lens1, *lens2;
1057 unsigned long fcode;
1058 int hval, disp, indx;
1060 fcode = BSD_KEY(oldcode,finchar);
1061 hval = BSD_HASH(oldcode,finchar,db->hshift);
1062 dictp = dict_ptr (db, hval);
1064 /* look for a free hash table entry */
1065 if (dictp->codem1 < max_ent)
1067 disp = (hval == 0) ? 1 : hval;
1071 if (hval >= db->hsize)
1075 dictp = dict_ptr (db, hval);
1077 while (dictp->codem1 < max_ent);
1081 * Invalidate previous hash table entry
1082 * assigned this code, and then take it over
1085 dictp2 = dict_ptr (db, max_ent + 1);
1086 indx = dictp2->cptr;
1087 dictp3 = dict_ptr (db, indx);
1089 if (dictp3->codem1 == max_ent)
1091 dictp3->codem1 = BADCODEM1;
1094 dictp2->cptr = hval;
1095 dictp->codem1 = max_ent;
1096 dictp->f.fcode = fcode;
1097 db->max_ent = ++max_ent;
1099 /* Update the length of this string. */
1100 lens1 = lens_ptr (db, max_ent);
1101 lens2 = lens_ptr (db, oldcode);
1102 *lens1 = *lens2 + 1;
1104 /* Expand code size if needed. */
1105 if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode)
1107 db->n_bits = ++n_bits;
1108 tgtbitno = 32-n_bits;
1116 db->comp_bytes += isize - BSD_OVHD - PPP_HDRLEN;
1117 db->uncomp_bytes += explen;
1123 printk("bsd_decomp%d: peer should have cleared dictionary on %d\n",
1124 db->unit, db->seqno - 1);
1130 /*************************************************************
1131 * Table of addresses for the BSD compression module
1132 *************************************************************/
1134 static struct compressor ppp_bsd_compress = {
1135 .compress_proto = CI_BSD_COMPRESS,
1136 .comp_alloc = bsd_comp_alloc,
1137 .comp_free = bsd_free,
1138 .comp_init = bsd_comp_init,
1139 .comp_reset = bsd_reset,
1140 .compress = bsd_compress,
1141 .comp_stat = bsd_comp_stats,
1142 .decomp_alloc = bsd_decomp_alloc,
1143 .decomp_free = bsd_free,
1144 .decomp_init = bsd_decomp_init,
1145 .decomp_reset = bsd_reset,
1146 .decompress = bsd_decompress,
1147 .incomp = bsd_incomp,
1148 .decomp_stat = bsd_comp_stats,
1149 .owner = THIS_MODULE
1152 /*************************************************************
1153 * Module support routines
1154 *************************************************************/
1156 static int __init bsdcomp_init(void)
1158 int answer = ppp_register_compressor(&ppp_bsd_compress);
1160 printk(KERN_INFO "PPP BSD Compression module registered\n");
1164 static void __exit bsdcomp_cleanup(void)
1166 ppp_unregister_compressor(&ppp_bsd_compress);
1169 module_init(bsdcomp_init);
1170 module_exit(bsdcomp_cleanup);
1171 MODULE_LICENSE("Dual BSD/GPL");
1172 MODULE_ALIAS("ppp-compress-" __stringify(CI_BSD_COMPRESS));