1 /* $Id: isdn_v110.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $
2 *
3 * Linux ISDN subsystem, V.110 related functions (linklevel).
4 *
5 * Copyright by Thomas Pfeiffer (pfeiffer@pds.de)
6 *
7 * This software may be used and distributed according to the terms
8 * of the GNU General Public License, incorporated herein by reference.
9 *
10 */
11
12 #include <linux/string.h>
13 #include <linux/kernel.h>
14 #include <linux/slab.h>
15 #include <linux/mm.h>
16 #include <linux/delay.h>
17
18 #include <linux/isdn.h>
19 #include "isdn_v110.h"
20
21 #undef ISDN_V110_DEBUG
22
23 char *isdn_v110_revision = "$Revision: 1.1.2.2 $";
24
25 #define V110_38400 255
26 #define V110_19200 15
27 #define V110_9600 3
28
29 /*
30 * The following data are precoded matrices, online and offline matrix
31 * for 9600, 19200 und 38400, respectively
32 */
33 static unsigned char V110_OnMatrix_9600[] =
34 {0xfc, 0xfc, 0xfc, 0xfc, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff,
35 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd,
36 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff,
37 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xfd};
38
39 static unsigned char V110_OffMatrix_9600[] =
40 {0xfc, 0xfc, 0xfc, 0xfc, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
41 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
42 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
43 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
44
45 static unsigned char V110_OnMatrix_19200[] =
46 {0xf0, 0xf0, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7,
47 0xfd, 0xff, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7, 0xff, 0xf7};
48
49 static unsigned char V110_OffMatrix_19200[] =
50 {0xf0, 0xf0, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
51 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
52
53 static unsigned char V110_OnMatrix_38400[] =
54 {0x00, 0x7f, 0x7f, 0x7f, 0x7f, 0xfd, 0x7f, 0x7f, 0x7f, 0x7f};
55
56 static unsigned char V110_OffMatrix_38400[] =
57 {0x00, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xff};
58
59 /*
60 * FlipBits reorders sequences of keylen bits in one byte.
61 * E.g. source order 7654321 will be converted to 45670123 when keylen = 4,
62 * and to 67452301 when keylen = 2. This is necessary because ordering on
63 * the isdn line is the other way.
64 */
65 static inline unsigned char
FlipBits(unsigned char c,int keylen)66 FlipBits(unsigned char c, int keylen)
67 {
68 unsigned char b = c;
69 unsigned char bit = 128;
70 int i;
71 int j;
72 int hunks = (8 / keylen);
73
74 c = 0;
75 for (i = 0; i < hunks; i++) {
76 for (j = 0; j < keylen; j++) {
77 if (b & (bit >> j))
78 c |= bit >> (keylen - j - 1);
79 }
80 bit >>= keylen;
81 }
82 return c;
83 }
84
85
86 /* isdn_v110_open allocates and initializes private V.110 data
87 * structures and returns a pointer to these.
88 */
89 static isdn_v110_stream *
isdn_v110_open(unsigned char key,int hdrlen,int maxsize)90 isdn_v110_open(unsigned char key, int hdrlen, int maxsize)
91 {
92 int i;
93 isdn_v110_stream *v;
94
95 if ((v = kzalloc(sizeof(isdn_v110_stream), GFP_ATOMIC)) == NULL)
96 return NULL;
97 v->key = key;
98 v->nbits = 0;
99 for (i = 0; key & (1 << i); i++)
100 v->nbits++;
101
102 v->nbytes = 8 / v->nbits;
103 v->decodelen = 0;
104
105 switch (key) {
106 case V110_38400:
107 v->OnlineFrame = V110_OnMatrix_38400;
108 v->OfflineFrame = V110_OffMatrix_38400;
109 break;
110 case V110_19200:
111 v->OnlineFrame = V110_OnMatrix_19200;
112 v->OfflineFrame = V110_OffMatrix_19200;
113 break;
114 default:
115 v->OnlineFrame = V110_OnMatrix_9600;
116 v->OfflineFrame = V110_OffMatrix_9600;
117 break;
118 }
119 v->framelen = v->nbytes * 10;
120 v->SyncInit = 5;
121 v->introducer = 0;
122 v->dbit = 1;
123 v->b = 0;
124 v->skbres = hdrlen;
125 v->maxsize = maxsize - hdrlen;
126 if ((v->encodebuf = kmalloc(maxsize, GFP_ATOMIC)) == NULL) {
127 kfree(v);
128 return NULL;
129 }
130 return v;
131 }
132
133 /* isdn_v110_close frees private V.110 data structures */
134 void
isdn_v110_close(isdn_v110_stream * v)135 isdn_v110_close(isdn_v110_stream *v)
136 {
137 if (v == NULL)
138 return;
139 #ifdef ISDN_V110_DEBUG
140 printk(KERN_DEBUG "v110 close\n");
141 #endif
142 kfree(v->encodebuf);
143 kfree(v);
144 }
145
146
147 /*
148 * ValidHeaderBytes return the number of valid bytes in v->decodebuf
149 */
150 static int
ValidHeaderBytes(isdn_v110_stream * v)151 ValidHeaderBytes(isdn_v110_stream *v)
152 {
153 int i;
154 for (i = 0; (i < v->decodelen) && (i < v->nbytes); i++)
155 if ((v->decodebuf[i] & v->key) != 0)
156 break;
157 return i;
158 }
159
160 /*
161 * SyncHeader moves the decodebuf ptr to the next valid header
162 */
163 static void
SyncHeader(isdn_v110_stream * v)164 SyncHeader(isdn_v110_stream *v)
165 {
166 unsigned char *rbuf = v->decodebuf;
167 int len = v->decodelen;
168
169 if (len == 0)
170 return;
171 for (rbuf++, len--; len > 0; len--, rbuf++) /* such den SyncHeader in buf ! */
172 if ((*rbuf & v->key) == 0) /* erstes byte gefunden ? */
173 break; /* jupp! */
174 if (len)
175 memcpy(v->decodebuf, rbuf, len);
176
177 v->decodelen = len;
178 #ifdef ISDN_V110_DEBUG
179 printk(KERN_DEBUG "isdn_v110: Header resync\n");
180 #endif
181 }
182
183 /* DecodeMatrix takes n (n>=1) matrices (v110 frames, 10 bytes) where
184 len is the number of matrix-lines. len must be a multiple of 10, i.e.
185 only complete matices must be given.
186 From these, netto data is extracted and returned in buf. The return-value
187 is the bytecount of the decoded data.
188 */
189 static int
DecodeMatrix(isdn_v110_stream * v,unsigned char * m,int len,unsigned char * buf)190 DecodeMatrix(isdn_v110_stream *v, unsigned char *m, int len, unsigned char *buf)
191 {
192 int line = 0;
193 int buflen = 0;
194 int mbit = 64;
195 int introducer = v->introducer;
196 int dbit = v->dbit;
197 unsigned char b = v->b;
198
199 while (line < len) { /* Are we done with all lines of the matrix? */
200 if ((line % 10) == 0) { /* the 0. line of the matrix is always 0 ! */
201 if (m[line] != 0x00) { /* not 0 ? -> error! */
202 #ifdef ISDN_V110_DEBUG
203 printk(KERN_DEBUG "isdn_v110: DecodeMatrix, V110 Bad Header\n");
204 /* returning now is not the right thing, though :-( */
205 #endif
206 }
207 line++; /* next line of matrix */
208 continue;
209 } else if ((line % 10) == 5) { /* in line 5 there's only e-bits ! */
210 if ((m[line] & 0x70) != 0x30) { /* 011 has to be at the beginning! */
211 #ifdef ISDN_V110_DEBUG
212 printk(KERN_DEBUG "isdn_v110: DecodeMatrix, V110 Bad 5th line\n");
213 /* returning now is not the right thing, though :-( */
214 #endif
215 }
216 line++; /* next line */
217 continue;
218 } else if (!introducer) { /* every byte starts with 10 (stopbit, startbit) */
219 introducer = (m[line] & mbit) ? 0 : 1; /* current bit of the matrix */
220 next_byte:
221 if (mbit > 2) { /* was it the last bit in this line ? */
222 mbit >>= 1; /* no -> take next */
223 continue;
224 } /* otherwise start with leftmost bit in the next line */
225 mbit = 64;
226 line++;
227 continue;
228 } else { /* otherwise we need to set a data bit */
229 if (m[line] & mbit) /* was that bit set in the matrix ? */
230 b |= dbit; /* yes -> set it in the data byte */
231 else
232 b &= dbit - 1; /* no -> clear it in the data byte */
233 if (dbit < 128) /* is that data byte done ? */
234 dbit <<= 1; /* no, got the next bit */
235 else { /* data byte is done */
236 buf[buflen++] = b; /* copy byte into the output buffer */
237 introducer = b = 0; /* init of the intro sequence and of the data byte */
238 dbit = 1; /* next we look for the 0th bit */
239 }
240 goto next_byte; /* look for next bit in the matrix */
241 }
242 }
243 v->introducer = introducer;
244 v->dbit = dbit;
245 v->b = b;
246 return buflen; /* return number of bytes in the output buffer */
247 }
248
249 /*
250 * DecodeStream receives V.110 coded data from the input stream. It recovers the
251 * original frames.
252 * The input stream doesn't need to be framed
253 */
254 struct sk_buff *
isdn_v110_decode(isdn_v110_stream * v,struct sk_buff * skb)255 isdn_v110_decode(isdn_v110_stream *v, struct sk_buff *skb)
256 {
257 int i;
258 int j;
259 int len;
260 unsigned char *v110_buf;
261 unsigned char *rbuf;
262
263 if (!skb) {
264 printk(KERN_WARNING "isdn_v110_decode called with NULL skb!\n");
265 return NULL;
266 }
267 rbuf = skb->data;
268 len = skb->len;
269 if (v == NULL) {
270 /* invalid handle, no chance to proceed */
271 printk(KERN_WARNING "isdn_v110_decode called with NULL stream!\n");
272 dev_kfree_skb(skb);
273 return NULL;
274 }
275 if (v->decodelen == 0) /* cache empty? */
276 for (; len > 0; len--, rbuf++) /* scan for SyncHeader in buf */
277 if ((*rbuf & v->key) == 0)
278 break; /* found first byte */
279 if (len == 0) {
280 dev_kfree_skb(skb);
281 return NULL;
282 }
283 /* copy new data to decode-buffer */
284 memcpy(&(v->decodebuf[v->decodelen]), rbuf, len);
285 v->decodelen += len;
286 ReSync:
287 if (v->decodelen < v->nbytes) { /* got a new header ? */
288 dev_kfree_skb(skb);
289 return NULL; /* no, try later */
290 }
291 if (ValidHeaderBytes(v) != v->nbytes) { /* is that a valid header? */
292 SyncHeader(v); /* no -> look for header */
293 goto ReSync;
294 }
295 len = (v->decodelen - (v->decodelen % (10 * v->nbytes))) / v->nbytes;
296 if ((v110_buf = kmalloc(len, GFP_ATOMIC)) == NULL) {
297 printk(KERN_WARNING "isdn_v110_decode: Couldn't allocate v110_buf\n");
298 dev_kfree_skb(skb);
299 return NULL;
300 }
301 for (i = 0; i < len; i++) {
302 v110_buf[i] = 0;
303 for (j = 0; j < v->nbytes; j++)
304 v110_buf[i] |= (v->decodebuf[(i * v->nbytes) + j] & v->key) << (8 - ((j + 1) * v->nbits));
305 v110_buf[i] = FlipBits(v110_buf[i], v->nbits);
306 }
307 v->decodelen = (v->decodelen % (10 * v->nbytes));
308 memcpy(v->decodebuf, &(v->decodebuf[len * v->nbytes]), v->decodelen);
309
310 skb_trim(skb, DecodeMatrix(v, v110_buf, len, skb->data));
311 kfree(v110_buf);
312 if (skb->len)
313 return skb;
314 else {
315 kfree_skb(skb);
316 return NULL;
317 }
318 }
319
320 /* EncodeMatrix takes input data in buf, len is the bytecount.
321 Data is encoded into v110 frames in m. Return value is the number of
322 matrix-lines generated.
323 */
324 static int
EncodeMatrix(unsigned char * buf,int len,unsigned char * m,int mlen)325 EncodeMatrix(unsigned char *buf, int len, unsigned char *m, int mlen)
326 {
327 int line = 0;
328 int i = 0;
329 int mbit = 128;
330 int dbit = 1;
331 int introducer = 3;
332 int ibit[] = {0, 1, 1};
333
334 while ((i < len) && (line < mlen)) { /* while we still have input data */
335 switch (line % 10) { /* in which line of the matrix are we? */
336 case 0:
337 m[line++] = 0x00; /* line 0 is always 0 */
338 mbit = 128; /* go on with the 7th bit */
339 break;
340 case 5:
341 m[line++] = 0xbf; /* line 5 is always 10111111 */
342 mbit = 128; /* go on with the 7th bit */
343 break;
344 }
345 if (line >= mlen) {
346 printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!\n");
347 return line;
348 }
349 next_bit:
350 switch (mbit) { /* leftmost or rightmost bit ? */
351 case 1:
352 line++; /* rightmost -> go to next line */
353 if (line >= mlen) {
354 printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!\n");
355 return line;
356 }
357 /* else: fall through */
358 case 128:
359 m[line] = 128; /* leftmost -> set byte to 1000000 */
360 mbit = 64; /* current bit in the matrix line */
361 continue;
362 }
363 if (introducer) { /* set 110 sequence ? */
364 introducer--; /* set on digit less */
365 m[line] |= ibit[introducer] ? mbit : 0; /* set corresponding bit */
366 mbit >>= 1; /* bit of matrix line >> 1 */
367 goto next_bit; /* and go on there */
368 } /* else push data bits into the matrix! */
369 m[line] |= (buf[i] & dbit) ? mbit : 0; /* set data bit in matrix */
370 if (dbit == 128) { /* was it the last one? */
371 dbit = 1; /* then go on with first bit of */
372 i++; /* next byte in input buffer */
373 if (i < len) /* input buffer done ? */
374 introducer = 3; /* no, write introducer 110 */
375 else { /* input buffer done ! */
376 m[line] |= (mbit - 1) & 0xfe; /* set remaining bits in line to 1 */
377 break;
378 }
379 } else /* not the last data bit */
380 dbit <<= 1; /* then go to next data bit */
381 mbit >>= 1; /* go to next bit of matrix */
382 goto next_bit;
383
384 }
385 /* if necessary, generate remaining lines of the matrix... */
386 if ((line) && ((line + 10) < mlen))
387 switch (++line % 10) {
388 case 1:
389 m[line++] = 0xfe;
390 /* fall through */
391 case 2:
392 m[line++] = 0xfe;
393 /* fall through */
394 case 3:
395 m[line++] = 0xfe;
396 /* fall through */
397 case 4:
398 m[line++] = 0xfe;
399 /* fall through */
400 case 5:
401 m[line++] = 0xbf;
402 /* fall through */
403 case 6:
404 m[line++] = 0xfe;
405 /* fall through */
406 case 7:
407 m[line++] = 0xfe;
408 /* fall through */
409 case 8:
410 m[line++] = 0xfe;
411 /* fall through */
412 case 9:
413 m[line++] = 0xfe;
414 }
415 return line; /* that's how many lines we have */
416 }
417
418 /*
419 * Build a sync frame.
420 */
421 static struct sk_buff *
isdn_v110_sync(isdn_v110_stream * v)422 isdn_v110_sync(isdn_v110_stream *v)
423 {
424 struct sk_buff *skb;
425
426 if (v == NULL) {
427 /* invalid handle, no chance to proceed */
428 printk(KERN_WARNING "isdn_v110_sync called with NULL stream!\n");
429 return NULL;
430 }
431 if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
432 skb_reserve(skb, v->skbres);
433 skb_put_data(skb, v->OfflineFrame, v->framelen);
434 }
435 return skb;
436 }
437
438 /*
439 * Build an idle frame.
440 */
441 static struct sk_buff *
isdn_v110_idle(isdn_v110_stream * v)442 isdn_v110_idle(isdn_v110_stream *v)
443 {
444 struct sk_buff *skb;
445
446 if (v == NULL) {
447 /* invalid handle, no chance to proceed */
448 printk(KERN_WARNING "isdn_v110_sync called with NULL stream!\n");
449 return NULL;
450 }
451 if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
452 skb_reserve(skb, v->skbres);
453 skb_put_data(skb, v->OnlineFrame, v->framelen);
454 }
455 return skb;
456 }
457
458 struct sk_buff *
isdn_v110_encode(isdn_v110_stream * v,struct sk_buff * skb)459 isdn_v110_encode(isdn_v110_stream *v, struct sk_buff *skb)
460 {
461 int i;
462 int j;
463 int rlen;
464 int mlen;
465 int olen;
466 int size;
467 int sval1;
468 int sval2;
469 int nframes;
470 unsigned char *v110buf;
471 unsigned char *rbuf;
472 struct sk_buff *nskb;
473
474 if (v == NULL) {
475 /* invalid handle, no chance to proceed */
476 printk(KERN_WARNING "isdn_v110_encode called with NULL stream!\n");
477 return NULL;
478 }
479 if (!skb) {
480 /* invalid skb, no chance to proceed */
481 printk(KERN_WARNING "isdn_v110_encode called with NULL skb!\n");
482 return NULL;
483 }
484 rlen = skb->len;
485 nframes = (rlen + 3) / 4;
486 v110buf = v->encodebuf;
487 if ((nframes * 40) > v->maxsize) {
488 size = v->maxsize;
489 rlen = v->maxsize / 40;
490 } else
491 size = nframes * 40;
492 if (!(nskb = dev_alloc_skb(size + v->skbres + sizeof(int)))) {
493 printk(KERN_WARNING "isdn_v110_encode: Couldn't alloc skb\n");
494 return NULL;
495 }
496 skb_reserve(nskb, v->skbres + sizeof(int));
497 if (skb->len == 0) {
498 skb_put_data(nskb, v->OnlineFrame, v->framelen);
499 *((int *)skb_push(nskb, sizeof(int))) = 0;
500 return nskb;
501 }
502 mlen = EncodeMatrix(skb->data, rlen, v110buf, size);
503 /* now distribute 2 or 4 bits each to the output stream! */
504 rbuf = skb_put(nskb, size);
505 olen = 0;
506 sval1 = 8 - v->nbits;
507 sval2 = v->key << sval1;
508 for (i = 0; i < mlen; i++) {
509 v110buf[i] = FlipBits(v110buf[i], v->nbits);
510 for (j = 0; j < v->nbytes; j++) {
511 if (size--)
512 *rbuf++ = ~v->key | (((v110buf[i] << (j * v->nbits)) & sval2) >> sval1);
513 else {
514 printk(KERN_WARNING "isdn_v110_encode: buffers full!\n");
515 goto buffer_full;
516 }
517 olen++;
518 }
519 }
520 buffer_full:
521 skb_trim(nskb, olen);
522 *((int *)skb_push(nskb, sizeof(int))) = rlen;
523 return nskb;
524 }
525
526 int
isdn_v110_stat_callback(int idx,isdn_ctrl * c)527 isdn_v110_stat_callback(int idx, isdn_ctrl *c)
528 {
529 isdn_v110_stream *v = NULL;
530 int i;
531 int ret = 0;
532
533 if (idx < 0)
534 return 0;
535 switch (c->command) {
536 case ISDN_STAT_BSENT:
537 /* Keep the send-queue of the driver filled
538 * with frames:
539 * If number of outstanding frames < 3,
540 * send down an Idle-Frame (or an Sync-Frame, if
541 * v->SyncInit != 0).
542 */
543 if (!(v = dev->v110[idx]))
544 return 0;
545 atomic_inc(&dev->v110use[idx]);
546 for (i = 0; i * v->framelen < c->parm.length; i++) {
547 if (v->skbidle > 0) {
548 v->skbidle--;
549 ret = 1;
550 } else {
551 if (v->skbuser > 0)
552 v->skbuser--;
553 ret = 0;
554 }
555 }
556 for (i = v->skbuser + v->skbidle; i < 2; i++) {
557 struct sk_buff *skb;
558 if (v->SyncInit > 0)
559 skb = isdn_v110_sync(v);
560 else
561 skb = isdn_v110_idle(v);
562 if (skb) {
563 if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
564 dev_kfree_skb(skb);
565 break;
566 } else {
567 if (v->SyncInit)
568 v->SyncInit--;
569 v->skbidle++;
570 }
571 } else
572 break;
573 }
574 atomic_dec(&dev->v110use[idx]);
575 return ret;
576 case ISDN_STAT_DHUP:
577 case ISDN_STAT_BHUP:
578 while (1) {
579 atomic_inc(&dev->v110use[idx]);
580 if (atomic_dec_and_test(&dev->v110use[idx])) {
581 isdn_v110_close(dev->v110[idx]);
582 dev->v110[idx] = NULL;
583 break;
584 }
585 mdelay(1);
586 }
587 break;
588 case ISDN_STAT_BCONN:
589 if (dev->v110emu[idx] && (dev->v110[idx] == NULL)) {
590 int hdrlen = dev->drv[c->driver]->interface->hl_hdrlen;
591 int maxsize = dev->drv[c->driver]->interface->maxbufsize;
592 atomic_inc(&dev->v110use[idx]);
593 switch (dev->v110emu[idx]) {
594 case ISDN_PROTO_L2_V11096:
595 dev->v110[idx] = isdn_v110_open(V110_9600, hdrlen, maxsize);
596 break;
597 case ISDN_PROTO_L2_V11019:
598 dev->v110[idx] = isdn_v110_open(V110_19200, hdrlen, maxsize);
599 break;
600 case ISDN_PROTO_L2_V11038:
601 dev->v110[idx] = isdn_v110_open(V110_38400, hdrlen, maxsize);
602 break;
603 default:;
604 }
605 if ((v = dev->v110[idx])) {
606 while (v->SyncInit) {
607 struct sk_buff *skb = isdn_v110_sync(v);
608 if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
609 dev_kfree_skb(skb);
610 /* Unable to send, try later */
611 break;
612 }
613 v->SyncInit--;
614 v->skbidle++;
615 }
616 } else
617 printk(KERN_WARNING "isdn_v110: Couldn't open stream for chan %d\n", idx);
618 atomic_dec(&dev->v110use[idx]);
619 }
620 break;
621 default:
622 return 0;
623 }
624 return 0;
625 }
626