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56#include <linux/module.h>
57#include <linux/init.h>
58#include <linux/kernel.h>
59#include <linux/types.h>
60#include <linux/fcntl.h>
61#include <linux/interrupt.h>
62#include <linux/ptrace.h>
63#include <linux/ioport.h>
64#include <linux/in.h>
65#include <linux/slab.h>
66#include <linux/tty.h>
67#include <linux/errno.h>
68#include <linux/string.h>
69#include <linux/signal.h>
70#include <linux/bitops.h>
71
72#include <asm/byteorder.h>
73#include <asm/types.h>
74
75#include <linux/if.h>
76
77#include <linux/if_ether.h>
78#include <linux/netdevice.h>
79#include <linux/skbuff.h>
80#include <linux/inet.h>
81#include <linux/ioctl.h>
82#include <linux/vmalloc.h>
83
84#include <linux/ppp_defs.h>
85
86#include <linux/isdn.h>
87#include <linux/isdn_ppp.h>
88#include <linux/ip.h>
89#include <linux/tcp.h>
90#include <linux/if_arp.h>
91#include <linux/ppp-comp.h>
92
93#include "isdn_ppp.h"
94
95MODULE_DESCRIPTION("ISDN4Linux: BSD Compression for PPP over ISDN");
96MODULE_LICENSE("Dual BSD/GPL");
97
98#define BSD_VERSION(x) ((x) >> 5)
99#define BSD_NBITS(x) ((x) & 0x1F)
100
101#define BSD_CURRENT_VERSION 1
102
103#define DEBUG 1
104
105
106
107
108
109struct bsd_dict {
110 u32 fcode;
111 u16 codem1;
112 u16 cptr;
113};
114
115struct bsd_db {
116 int totlen;
117 unsigned int hsize;
118 unsigned char hshift;
119 unsigned char n_bits;
120 unsigned char maxbits;
121 unsigned char debug;
122 unsigned char unit;
123 u16 seqno;
124 unsigned int mru;
125 unsigned int maxmaxcode;
126 unsigned int max_ent;
127 unsigned int in_count;
128 unsigned int bytes_out;
129 unsigned int ratio;
130 unsigned int checkpoint;
131 unsigned int clear_count;
132 unsigned int incomp_count;
133 unsigned int incomp_bytes;
134 unsigned int uncomp_count;
135 unsigned int uncomp_bytes;
136 unsigned int comp_count;
137 unsigned int comp_bytes;
138 unsigned short *lens;
139 struct bsd_dict *dict;
140 int xmit;
141};
142
143#define BSD_OVHD 2
144#define MIN_BSD_BITS 9
145#define BSD_INIT_BITS MIN_BSD_BITS
146#define MAX_BSD_BITS 15
147
148
149
150
151
152#define CLEAR 256
153#define FIRST 257
154#define LAST 255
155
156#define MAXCODE(b) ((1 << (b)) - 1)
157#define BADCODEM1 MAXCODE(MAX_BSD_BITS)
158
159#define BSD_HASH(prefix, suffix, hshift) ((((unsigned long)(suffix)) << (hshift)) \
160 ^ (unsigned long)(prefix))
161#define BSD_KEY(prefix, suffix) ((((unsigned long)(suffix)) << 16) \
162 + (unsigned long)(prefix))
163
164#define CHECK_GAP 10000
165
166#define RATIO_SCALE_LOG 8
167#define RATIO_SCALE (1 << RATIO_SCALE_LOG)
168#define RATIO_MAX (0x7fffffff >> RATIO_SCALE_LOG)
169
170
171
172
173
174static void bsd_clear(struct bsd_db *db)
175{
176 db->clear_count++;
177 db->max_ent = FIRST - 1;
178 db->n_bits = BSD_INIT_BITS;
179 db->bytes_out = 0;
180 db->in_count = 0;
181 db->incomp_count = 0;
182 db->ratio = 0;
183 db->checkpoint = CHECK_GAP;
184}
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199static int bsd_check(struct bsd_db *db)
200{
201 unsigned int new_ratio;
202
203 if (db->in_count >= db->checkpoint)
204 {
205
206 if (db->in_count >= RATIO_MAX || db->bytes_out >= RATIO_MAX)
207 {
208 db->in_count -= (db->in_count >> 2);
209 db->bytes_out -= (db->bytes_out >> 2);
210 }
211
212 db->checkpoint = db->in_count + CHECK_GAP;
213
214 if (db->max_ent >= db->maxmaxcode)
215 {
216
217
218
219
220
221
222
223
224 new_ratio = db->in_count << RATIO_SCALE_LOG;
225 if (db->bytes_out != 0)
226 {
227 new_ratio /= db->bytes_out;
228 }
229
230 if (new_ratio < db->ratio || new_ratio < 1 * RATIO_SCALE)
231 {
232 bsd_clear(db);
233 return 1;
234 }
235 db->ratio = new_ratio;
236 }
237 }
238 return 0;
239}
240
241
242
243
244
245static void bsd_stats(void *state, struct compstat *stats)
246{
247 struct bsd_db *db = (struct bsd_db *) state;
248
249 stats->unc_bytes = db->uncomp_bytes;
250 stats->unc_packets = db->uncomp_count;
251 stats->comp_bytes = db->comp_bytes;
252 stats->comp_packets = db->comp_count;
253 stats->inc_bytes = db->incomp_bytes;
254 stats->inc_packets = db->incomp_count;
255 stats->in_count = db->in_count;
256 stats->bytes_out = db->bytes_out;
257}
258
259
260
261
262static void bsd_reset(void *state, unsigned char code, unsigned char id,
263 unsigned char *data, unsigned len,
264 struct isdn_ppp_resetparams *rsparm)
265{
266 struct bsd_db *db = (struct bsd_db *) state;
267
268 bsd_clear(db);
269 db->seqno = 0;
270 db->clear_count = 0;
271}
272
273
274
275
276static void bsd_free(void *state)
277{
278 struct bsd_db *db = (struct bsd_db *) state;
279
280 if (db) {
281
282
283
284 vfree(db->dict);
285 db->dict = NULL;
286
287
288
289
290 vfree(db->lens);
291 db->lens = NULL;
292
293
294
295
296 kfree(db);
297 }
298}
299
300
301
302
303
304static void *bsd_alloc(struct isdn_ppp_comp_data *data)
305{
306 int bits;
307 unsigned int hsize, hshift, maxmaxcode;
308 struct bsd_db *db;
309 int decomp;
310
311 static unsigned int htab[][2] = {
312 { 5003 , 4 } , { 5003 , 4 } , { 5003 , 4 } , { 5003 , 4 } ,
313 { 9001 , 5 } , { 18013 , 6 } , { 35023 , 7 } , { 69001 , 8 }
314 };
315
316 if (data->optlen != 1 || data->num != CI_BSD_COMPRESS
317 || BSD_VERSION(data->options[0]) != BSD_CURRENT_VERSION)
318 return NULL;
319
320 bits = BSD_NBITS(data->options[0]);
321
322 if (bits < 9 || bits > 15)
323 return NULL;
324
325 hsize = htab[bits - 9][0];
326 hshift = htab[bits - 9][1];
327
328
329
330
331 maxmaxcode = MAXCODE(bits);
332 db = kzalloc(sizeof(struct bsd_db), GFP_KERNEL);
333 if (!db)
334 return NULL;
335
336 db->xmit = data->flags & IPPP_COMP_FLAG_XMIT;
337 decomp = db->xmit ? 0 : 1;
338
339
340
341
342
343 db->dict = vmalloc(hsize * sizeof(struct bsd_dict));
344 if (!db->dict) {
345 bsd_free(db);
346 return NULL;
347 }
348
349
350
351
352
353 if (!decomp)
354 db->lens = NULL;
355 else {
356 db->lens = vmalloc((maxmaxcode + 1) * sizeof(db->lens[0]));
357 if (!db->lens) {
358 bsd_free(db);
359 return (NULL);
360 }
361 }
362
363
364
365
366 db->totlen = sizeof(struct bsd_db) + (sizeof(struct bsd_dict) * hsize);
367 db->hsize = hsize;
368 db->hshift = hshift;
369 db->maxmaxcode = maxmaxcode;
370 db->maxbits = bits;
371
372 return (void *)db;
373}
374
375
376
377
378static int bsd_init(void *state, struct isdn_ppp_comp_data *data, int unit, int debug)
379{
380 struct bsd_db *db = state;
381 int indx;
382 int decomp;
383
384 if (!state || !data) {
385 printk(KERN_ERR "isdn_bsd_init: [%d] ERR, state %lx data %lx\n", unit, (long)state, (long)data);
386 return 0;
387 }
388
389 decomp = db->xmit ? 0 : 1;
390
391 if (data->optlen != 1 || data->num != CI_BSD_COMPRESS
392 || (BSD_VERSION(data->options[0]) != BSD_CURRENT_VERSION)
393 || (BSD_NBITS(data->options[0]) != db->maxbits)
394 || (decomp && db->lens == NULL)) {
395 printk(KERN_ERR "isdn_bsd: %d %d %d %d %lx\n", data->optlen, data->num, data->options[0], decomp, (unsigned long)db->lens);
396 return 0;
397 }
398
399 if (decomp)
400 for (indx = LAST; indx >= 0; indx--)
401 db->lens[indx] = 1;
402
403 indx = db->hsize;
404 while (indx-- != 0) {
405 db->dict[indx].codem1 = BADCODEM1;
406 db->dict[indx].cptr = 0;
407 }
408
409 db->unit = unit;
410 db->mru = 0;
411
412 db->debug = 1;
413
414 bsd_reset(db, 0, 0, NULL, 0, NULL);
415
416 return 1;
417}
418
419
420
421
422
423#define dict_ptrx(p, idx) &(p->dict[idx])
424#define lens_ptrx(p, idx) &(p->lens[idx])
425
426#ifdef DEBUG
427static unsigned short *lens_ptr(struct bsd_db *db, int idx)
428{
429 if ((unsigned int) idx > (unsigned int) db->maxmaxcode) {
430 printk(KERN_DEBUG "<9>ppp: lens_ptr(%d) > max\n", idx);
431 idx = 0;
432 }
433 return lens_ptrx(db, idx);
434}
435
436static struct bsd_dict *dict_ptr(struct bsd_db *db, int idx)
437{
438 if ((unsigned int) idx >= (unsigned int) db->hsize) {
439 printk(KERN_DEBUG "<9>ppp: dict_ptr(%d) > max\n", idx);
440 idx = 0;
441 }
442 return dict_ptrx(db, idx);
443}
444
445#else
446#define lens_ptr(db, idx) lens_ptrx(db, idx)
447#define dict_ptr(db, idx) dict_ptrx(db, idx)
448#endif
449
450
451
452
453static int bsd_compress(void *state, struct sk_buff *skb_in, struct sk_buff *skb_out, int proto)
454{
455 struct bsd_db *db;
456 int hshift;
457 unsigned int max_ent;
458 unsigned int n_bits;
459 unsigned int bitno;
460 unsigned long accm;
461 int ent;
462 unsigned long fcode;
463 struct bsd_dict *dictp;
464 unsigned char c;
465 int hval, disp, ilen, mxcode;
466 unsigned char *rptr = skb_in->data;
467 int isize = skb_in->len;
468
469#define OUTPUT(ent) \
470 { \
471 bitno -= n_bits; \
472 accm |= ((ent) << bitno); \
473 do { \
474 if (skb_out && skb_tailroom(skb_out) > 0) \
475 skb_put_u8(skb_out, (u8)(accm >> 24)); \
476 accm <<= 8; \
477 bitno += 8; \
478 } while (bitno <= 24); \
479 }
480
481
482
483
484
485
486 printk(KERN_DEBUG "bsd_compress called with %x\n", proto);
487
488 ent = proto;
489 if (proto < 0x21 || proto > 0xf9 || !(proto & 0x1))
490 return 0;
491
492 db = (struct bsd_db *) state;
493 hshift = db->hshift;
494 max_ent = db->max_ent;
495 n_bits = db->n_bits;
496 bitno = 32;
497 accm = 0;
498 mxcode = MAXCODE(n_bits);
499
500
501 if (skb_out && skb_tailroom(skb_out) >= 2) {
502 char *v = skb_put(skb_out, 2);
503
504
505 v[0] = db->seqno >> 8;
506 v[1] = db->seqno;
507 }
508
509 ilen = ++isize;
510
511 while (--ilen > 0) {
512 c = *rptr++;
513 fcode = BSD_KEY(ent, c);
514 hval = BSD_HASH(ent, c, hshift);
515 dictp = dict_ptr(db, hval);
516
517
518 if (dictp->codem1 >= max_ent)
519 goto nomatch;
520
521 if (dictp->fcode == fcode) {
522 ent = dictp->codem1 + 1;
523 continue;
524 }
525
526
527 disp = (hval == 0) ? 1 : hval;
528
529 do {
530 hval += disp;
531 if (hval >= db->hsize)
532 hval -= db->hsize;
533 dictp = dict_ptr(db, hval);
534 if (dictp->codem1 >= max_ent)
535 goto nomatch;
536 } while (dictp->fcode != fcode);
537
538 ent = dictp->codem1 + 1;
539 continue;
540
541 nomatch:
542 OUTPUT(ent);
543
544
545 if (max_ent < db->maxmaxcode) {
546 struct bsd_dict *dictp2;
547 struct bsd_dict *dictp3;
548 int indx;
549
550
551 if (max_ent >= mxcode) {
552 db->n_bits = ++n_bits;
553 mxcode = MAXCODE(n_bits);
554 }
555
556
557
558
559
560 dictp2 = dict_ptr(db, max_ent + 1);
561 indx = dictp2->cptr;
562 dictp3 = dict_ptr(db, indx);
563
564 if (dictp3->codem1 == max_ent)
565 dictp3->codem1 = BADCODEM1;
566
567 dictp2->cptr = hval;
568 dictp->codem1 = max_ent;
569 dictp->fcode = fcode;
570 db->max_ent = ++max_ent;
571
572 if (db->lens) {
573 unsigned short *len1 = lens_ptr(db, max_ent);
574 unsigned short *len2 = lens_ptr(db, ent);
575 *len1 = *len2 + 1;
576 }
577 }
578 ent = c;
579 }
580
581 OUTPUT(ent);
582
583 if (skb_out)
584 db->bytes_out += skb_out->len;
585 db->uncomp_bytes += isize;
586 db->in_count += isize;
587 ++db->uncomp_count;
588 ++db->seqno;
589
590 if (bitno < 32)
591 ++db->bytes_out;
592
593
594
595
596
597 if (bsd_check(db))
598 OUTPUT(CLEAR);
599
600
601
602
603
604 if (bitno < 32 && skb_out && skb_tailroom(skb_out) > 0)
605 skb_put_u8(skb_out,
606 (unsigned char)((accm | (0xff << (bitno - 8))) >> 24));
607
608
609
610
611
612 if (max_ent >= mxcode && max_ent < db->maxmaxcode)
613 db->n_bits++;
614
615
616 if (!skb_out || skb_out->len >= skb_in->len) {
617 ++db->incomp_count;
618 db->incomp_bytes += isize;
619 return 0;
620 }
621
622
623 ++db->comp_count;
624 db->comp_bytes += skb_out->len;
625 return skb_out->len;
626
627#undef OUTPUT
628}
629
630
631
632
633
634static void bsd_incomp(void *state, struct sk_buff *skb_in, int proto)
635{
636 bsd_compress(state, skb_in, NULL, proto);
637}
638
639
640
641
642static int bsd_decompress(void *state, struct sk_buff *skb_in, struct sk_buff *skb_out,
643 struct isdn_ppp_resetparams *rsparm)
644{
645 struct bsd_db *db;
646 unsigned int max_ent;
647 unsigned long accm;
648 unsigned int bitno;
649 unsigned int n_bits;
650 unsigned int tgtbitno;
651 struct bsd_dict *dictp;
652 int seq;
653 unsigned int incode;
654 unsigned int oldcode;
655 unsigned int finchar;
656 unsigned char *p, *ibuf;
657 int ilen;
658 int codelen;
659 int extra;
660
661 db = (struct bsd_db *) state;
662 max_ent = db->max_ent;
663 accm = 0;
664 bitno = 32;
665 n_bits = db->n_bits;
666 tgtbitno = 32 - n_bits;
667
668 printk(KERN_DEBUG "bsd_decompress called\n");
669
670 if (!skb_in || !skb_out) {
671 printk(KERN_ERR "bsd_decompress called with NULL parameter\n");
672 return DECOMP_ERROR;
673 }
674
675
676
677
678 if ((p = skb_pull(skb_in, 2)) == NULL) {
679 return DECOMP_ERROR;
680 }
681 p -= 2;
682 seq = (p[0] << 8) + p[1];
683 ilen = skb_in->len;
684 ibuf = skb_in->data;
685
686
687
688
689
690 if (seq != db->seqno) {
691 if (db->debug) {
692 printk(KERN_DEBUG "bsd_decomp%d: bad sequence # %d, expected %d\n",
693 db->unit, seq, db->seqno - 1);
694 }
695 return DECOMP_ERROR;
696 }
697
698 ++db->seqno;
699 db->bytes_out += ilen;
700
701 if (skb_tailroom(skb_out) > 0)
702 skb_put_u8(skb_out, 0);
703 else
704 return DECOMP_ERR_NOMEM;
705
706 oldcode = CLEAR;
707
708
709
710
711
712
713 for (;;) {
714 if (ilen-- <= 0) {
715 db->in_count += (skb_out->len - 1);
716 break;
717 }
718
719
720
721
722
723
724
725 bitno -= 8;
726 accm |= *ibuf++ << bitno;
727 if (tgtbitno < bitno)
728 continue;
729
730 incode = accm >> tgtbitno;
731 accm <<= n_bits;
732 bitno += n_bits;
733
734
735
736
737
738 if (incode == CLEAR) {
739 if (ilen > 0) {
740 if (db->debug)
741 printk(KERN_DEBUG "bsd_decomp%d: bad CLEAR\n", db->unit);
742 return DECOMP_FATALERROR;
743 }
744 bsd_clear(db);
745 break;
746 }
747
748 if ((incode > max_ent + 2) || (incode > db->maxmaxcode)
749 || (incode > max_ent && oldcode == CLEAR)) {
750 if (db->debug) {
751 printk(KERN_DEBUG "bsd_decomp%d: bad code 0x%x oldcode=0x%x ",
752 db->unit, incode, oldcode);
753 printk(KERN_DEBUG "max_ent=0x%x skb->Len=%d seqno=%d\n",
754 max_ent, skb_out->len, db->seqno);
755 }
756 return DECOMP_FATALERROR;
757 }
758
759
760 if (incode > max_ent) {
761 finchar = oldcode;
762 extra = 1;
763 } else {
764 finchar = incode;
765 extra = 0;
766 }
767
768 codelen = *(lens_ptr(db, finchar));
769 if (skb_tailroom(skb_out) < codelen + extra) {
770 if (db->debug) {
771 printk(KERN_DEBUG "bsd_decomp%d: ran out of mru\n", db->unit);
772#ifdef DEBUG
773 printk(KERN_DEBUG " len=%d, finchar=0x%x, codelen=%d,skblen=%d\n",
774 ilen, finchar, codelen, skb_out->len);
775#endif
776 }
777 return DECOMP_FATALERROR;
778 }
779
780
781
782
783
784 p = skb_put(skb_out, codelen);
785 p += codelen;
786 while (finchar > LAST) {
787 struct bsd_dict *dictp2 = dict_ptr(db, finchar);
788
789 dictp = dict_ptr(db, dictp2->cptr);
790
791#ifdef DEBUG
792 if (--codelen <= 0 || dictp->codem1 != finchar - 1) {
793 if (codelen <= 0) {
794 printk(KERN_ERR "bsd_decomp%d: fell off end of chain ", db->unit);
795 printk(KERN_ERR "0x%x at 0x%x by 0x%x, max_ent=0x%x\n", incode, finchar, dictp2->cptr, max_ent);
796 } else {
797 if (dictp->codem1 != finchar - 1) {
798 printk(KERN_ERR "bsd_decomp%d: bad code chain 0x%x finchar=0x%x ", db->unit, incode, finchar);
799 printk(KERN_ERR "oldcode=0x%x cptr=0x%x codem1=0x%x\n", oldcode, dictp2->cptr, dictp->codem1);
800 }
801 }
802 return DECOMP_FATALERROR;
803 }
804#endif
805
806 {
807 u32 fcode = dictp->fcode;
808 *--p = (fcode >> 16) & 0xff;
809 finchar = fcode & 0xffff;
810 }
811 }
812 *--p = finchar;
813
814#ifdef DEBUG
815 if (--codelen != 0)
816 printk(KERN_ERR "bsd_decomp%d: short by %d after code 0x%x, max_ent=0x%x\n", db->unit, codelen, incode, max_ent);
817#endif
818
819 if (extra)
820 skb_put_u8(skb_out, finchar);
821
822
823
824
825
826
827
828
829 if (oldcode != CLEAR && max_ent < db->maxmaxcode) {
830 struct bsd_dict *dictp2, *dictp3;
831 u16 *lens1, *lens2;
832 unsigned long fcode;
833 int hval, disp, indx;
834
835 fcode = BSD_KEY(oldcode, finchar);
836 hval = BSD_HASH(oldcode, finchar, db->hshift);
837 dictp = dict_ptr(db, hval);
838
839
840 if (dictp->codem1 < max_ent) {
841 disp = (hval == 0) ? 1 : hval;
842 do {
843 hval += disp;
844 if (hval >= db->hsize)
845 hval -= db->hsize;
846 dictp = dict_ptr(db, hval);
847 } while (dictp->codem1 < max_ent);
848 }
849
850
851
852
853
854
855 dictp2 = dict_ptr(db, max_ent + 1);
856 indx = dictp2->cptr;
857 dictp3 = dict_ptr(db, indx);
858
859 if (dictp3->codem1 == max_ent)
860 dictp3->codem1 = BADCODEM1;
861
862 dictp2->cptr = hval;
863 dictp->codem1 = max_ent;
864 dictp->fcode = fcode;
865 db->max_ent = ++max_ent;
866
867
868 lens1 = lens_ptr(db, max_ent);
869 lens2 = lens_ptr(db, oldcode);
870 *lens1 = *lens2 + 1;
871
872
873 if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode) {
874 db->n_bits = ++n_bits;
875 tgtbitno = 32-n_bits;
876 }
877 }
878 oldcode = incode;
879 }
880
881 ++db->comp_count;
882 ++db->uncomp_count;
883 db->comp_bytes += skb_in->len - BSD_OVHD;
884 db->uncomp_bytes += skb_out->len;
885
886 if (bsd_check(db)) {
887 if (db->debug)
888 printk(KERN_DEBUG "bsd_decomp%d: peer should have cleared dictionary on %d\n",
889 db->unit, db->seqno - 1);
890 }
891 return skb_out->len;
892}
893
894
895
896
897
898static struct isdn_ppp_compressor ippp_bsd_compress = {
899 .owner = THIS_MODULE,
900 .num = CI_BSD_COMPRESS,
901 .alloc = bsd_alloc,
902 .free = bsd_free,
903 .init = bsd_init,
904 .reset = bsd_reset,
905 .compress = bsd_compress,
906 .decompress = bsd_decompress,
907 .incomp = bsd_incomp,
908 .stat = bsd_stats,
909};
910
911
912
913
914
915static int __init isdn_bsdcomp_init(void)
916{
917 int answer = isdn_ppp_register_compressor(&ippp_bsd_compress);
918 if (answer == 0)
919 printk(KERN_INFO "PPP BSD Compression module registered\n");
920 return answer;
921}
922
923static void __exit isdn_bsdcomp_exit(void)
924{
925 isdn_ppp_unregister_compressor(&ippp_bsd_compress);
926}
927
928module_init(isdn_bsdcomp_init);
929module_exit(isdn_bsdcomp_exit);
930