aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/isdn/gigaset/asyncdata.c
blob: ddf5e92be44429cc3b3c679844933b8e11d2a6a5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
/*
 * Common data handling layer for ser_gigaset and usb_gigaset
 *
 * Copyright (c) 2005 by Tilman Schmidt <tilman@imap.cc>,
 *                       Hansjoerg Lipp <hjlipp@web.de>,
 *                       Stefan Eilers.
 *
 * =====================================================================
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License as
 *	published by the Free Software Foundation; either version 2 of
 *	the License, or (at your option) any later version.
 * =====================================================================
 */

/* not set by Kbuild when building both ser_gigaset and usb_gigaset */
#ifndef KBUILD_MODNAME
#define KBUILD_MODNAME "asy_gigaset"
#endif

#include "gigaset.h"
#include <linux/crc-ccitt.h>
#include <linux/bitrev.h>

//#define GIG_M10x_STUFF_VOICE_DATA

/* check if byte must be stuffed/escaped
 * I'm not sure which data should be encoded.
 * Therefore I will go the hard way and decode every value
 * less than 0x20, the flag sequence and the control escape char.
 */
static inline int muststuff(unsigned char c)
{
	if (c < PPP_TRANS) return 1;
	if (c == PPP_FLAG) return 1;
	if (c == PPP_ESCAPE) return 1;
	/* other possible candidates: */
	/* 0x91: XON with parity set */
	/* 0x93: XOFF with parity set */
	return 0;
}

/* == data input =========================================================== */

/* process a block of received bytes in command mode (modem response)
 * Return value:
 *	number of processed bytes
 */
static inline int cmd_loop(unsigned char c, unsigned char *src, int numbytes,
			   struct inbuf_t *inbuf)
{
	struct cardstate *cs = inbuf->cs;
	unsigned cbytes      = cs->cbytes;
	int inputstate = inbuf->inputstate;
	int startbytes = numbytes;

	for (;;) {
		cs->respdata[cbytes] = c;
		if (c == 10 || c == 13) {
			gig_dbg(DEBUG_TRANSCMD, "%s: End of Command (%d Bytes)",
				__func__, cbytes);
			cs->cbytes = cbytes;
			gigaset_handle_modem_response(cs); /* can change
							      cs->dle */
			cbytes = 0;

			if (cs->dle &&
			    !(inputstate & INS_DLE_command)) {
				inputstate &= ~INS_command;
				break;
			}
		} else {
			/* advance in line buffer, checking for overflow */
			if (cbytes < MAX_RESP_SIZE - 1)
				cbytes++;
			else
				dev_warn(cs->dev, "response too large\n");
		}

		if (!numbytes)
			break;
		c = *src++;
		--numbytes;
		if (c == DLE_FLAG &&
		    (cs->dle || inputstate & INS_DLE_command)) {
			inputstate |= INS_DLE_char;
			break;
		}
	}

	cs->cbytes = cbytes;
	inbuf->inputstate = inputstate;

	return startbytes - numbytes;
}

/* process a block of received bytes in lock mode (tty i/f)
 * Return value:
 *	number of processed bytes
 */
static inline int lock_loop(unsigned char *src, int numbytes,
			    struct inbuf_t *inbuf)
{
	struct cardstate *cs = inbuf->cs;

	gigaset_dbg_buffer(DEBUG_LOCKCMD, "received response",
			   numbytes, src);
	gigaset_if_receive(cs, src, numbytes);

	return numbytes;
}

/* process a block of received bytes in HDLC data mode
 * Collect HDLC frames, undoing byte stuffing and watching for DLE escapes.
 * When a frame is complete, check the FCS and pass valid frames to the LL.
 * If DLE is encountered, return immediately to let the caller handle it.
 * Return value:
 *	number of processed bytes
 *	numbytes (all bytes processed) on error --FIXME
 */
static inline int hdlc_loop(unsigned char c, unsigned char *src, int numbytes,
			    struct inbuf_t *inbuf)
{
	struct cardstate *cs = inbuf->cs;
	struct bc_state *bcs = inbuf->bcs;
	int inputstate = bcs->inputstate;
	__u16 fcs = bcs->fcs;
	struct sk_buff *skb = bcs->skb;
	unsigned char error;
	struct sk_buff *compskb;
	int startbytes = numbytes;
	int l;

	if (unlikely(inputstate & INS_byte_stuff)) {
		inputstate &= ~INS_byte_stuff;
		goto byte_stuff;
	}
	for (;;) {
		if (unlikely(c == PPP_ESCAPE)) {
			if (unlikely(!numbytes)) {
				inputstate |= INS_byte_stuff;
				break;
			}
			c = *src++;
			--numbytes;
			if (unlikely(c == DLE_FLAG &&
				     (cs->dle ||
				      inbuf->inputstate & INS_DLE_command))) {
				inbuf->inputstate |= INS_DLE_char;
				inputstate |= INS_byte_stuff;
				break;
			}
byte_stuff:
			c ^= PPP_TRANS;
#ifdef CONFIG_GIGASET_DEBUG
			if (unlikely(!muststuff(c)))
				gig_dbg(DEBUG_HDLC, "byte stuffed: 0x%02x", c);
#endif
		} else if (unlikely(c == PPP_FLAG)) {
			if (unlikely(inputstate & INS_skip_frame)) {
				if (!(inputstate & INS_have_data)) { /* 7E 7E */
#ifdef CONFIG_GIGASET_DEBUG
					++bcs->emptycount;
#endif
				} else
					gig_dbg(DEBUG_HDLC,
					    "7e----------------------------");

				/* end of frame */
				error = 1;
				gigaset_rcv_error(NULL, cs, bcs);
			} else if (!(inputstate & INS_have_data)) { /* 7E 7E */
#ifdef CONFIG_GIGASET_DEBUG
				++bcs->emptycount;
#endif
				break;
			} else {
				gig_dbg(DEBUG_HDLC,
					"7e----------------------------");

				/* end of frame */
				error = 0;

				if (unlikely(fcs != PPP_GOODFCS)) {
					dev_err(cs->dev,
					    "Packet checksum at %lu failed, "
					    "packet is corrupted (%u bytes)!\n",
					    bcs->rcvbytes, skb->len);
					compskb = NULL;
					gigaset_rcv_error(compskb, cs, bcs);
					error = 1;
				} else {
					if (likely((l = skb->len) > 2)) {
						skb->tail -= 2;
						skb->len -= 2;
					} else {
						dev_kfree_skb(skb);
						skb = NULL;
						inputstate |= INS_skip_frame;
						if (l == 1) {
							dev_err(cs->dev,
						  "invalid packet size (1)!\n");
							error = 1;
							gigaset_rcv_error(NULL,
								cs, bcs);
						}
					}
					if (likely(!(error ||
						     (inputstate &
						      INS_skip_frame)))) {
						gigaset_rcv_skb(skb, cs, bcs);
					}
				}
			}

			if (unlikely(error))
				if (skb)
					dev_kfree_skb(skb);

			fcs = PPP_INITFCS;
			inputstate &= ~(INS_have_data | INS_skip_frame);
			if (unlikely(bcs->ignore)) {
				inputstate |= INS_skip_frame;
				skb = NULL;
			} else if (likely((skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN)) != NULL)) {
				skb_reserve(skb, HW_HDR_LEN);
			} else {
				dev_warn(cs->dev,
					 "could not allocate new skb\n");
				inputstate |= INS_skip_frame;
			}

			break;
#ifdef CONFIG_GIGASET_DEBUG
		} else if (unlikely(muststuff(c))) {
			/* Should not happen. Possible after ZDLE=1<CR><LF>. */
			gig_dbg(DEBUG_HDLC, "not byte stuffed: 0x%02x", c);
#endif
		}

		/* add character */

#ifdef CONFIG_GIGASET_DEBUG
		if (unlikely(!(inputstate & INS_have_data))) {
			gig_dbg(DEBUG_HDLC, "7e (%d x) ================",
				bcs->emptycount);
			bcs->emptycount = 0;
		}
#endif

		inputstate |= INS_have_data;

		if (likely(!(inputstate & INS_skip_frame))) {
			if (unlikely(skb->len == SBUFSIZE)) {
				dev_warn(cs->dev, "received packet too long\n");
				dev_kfree_skb_any(skb);
				skb = NULL;
				inputstate |= INS_skip_frame;
				break;
			}
			*__skb_put(skb, 1) = c;
			fcs = crc_ccitt_byte(fcs, c);
		}

		if (unlikely(!numbytes))
			break;
		c = *src++;
		--numbytes;
		if (unlikely(c == DLE_FLAG &&
			     (cs->dle ||
			      inbuf->inputstate & INS_DLE_command))) {
			inbuf->inputstate |= INS_DLE_char;
			break;
		}
	}
	bcs->inputstate = inputstate;
	bcs->fcs = fcs;
	bcs->skb = skb;
	return startbytes - numbytes;
}

/* process a block of received bytes in transparent data mode
 * Invert bytes, undoing byte stuffing and watching for DLE escapes.
 * If DLE is encountered, return immediately to let the caller handle it.
 * Return value:
 *	number of processed bytes
 *	numbytes (all bytes processed) on error --FIXME
 */
static inline int iraw_loop(unsigned char c, unsigned char *src, int numbytes,
			    struct inbuf_t *inbuf)
{
	struct cardstate *cs = inbuf->cs;
	struct bc_state *bcs = inbuf->bcs;
	int inputstate = bcs->inputstate;
	struct sk_buff *skb = bcs->skb;
	int startbytes = numbytes;

	for (;;) {
		/* add character */
		inputstate |= INS_have_data;

		if (likely(!(inputstate & INS_skip_frame))) {
			if (unlikely(skb->len == SBUFSIZE)) {
				//FIXME just pass skb up and allocate a new one
				dev_warn(cs->dev, "received packet too long\n");
				dev_kfree_skb_any(skb);
				skb = NULL;
				inputstate |= INS_skip_frame;
				break;
			}
			*__skb_put(skb, 1) = bitrev8(c);
		}

		if (unlikely(!numbytes))
			break;
		c = *src++;
		--numbytes;
		if (unlikely(c == DLE_FLAG &&
			     (cs->dle ||
			      inbuf->inputstate & INS_DLE_command))) {
			inbuf->inputstate |= INS_DLE_char;
			break;
		}
	}

	/* pass data up */
	if (likely(inputstate & INS_have_data)) {
		if (likely(!(inputstate & INS_skip_frame))) {
			gigaset_rcv_skb(skb, cs, bcs);
		}
		inputstate &= ~(INS_have_data | INS_skip_frame);
		if (unlikely(bcs->ignore)) {
			inputstate |= INS_skip_frame;
			skb = NULL;
		} else if (likely((skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN))
				  != NULL)) {
			skb_reserve(skb, HW_HDR_LEN);
		} else {
			dev_warn(cs->dev, "could not allocate new skb\n");
			inputstate |= INS_skip_frame;
		}
	}

	bcs->inputstate = inputstate;
	bcs->skb = skb;
	return startbytes - numbytes;
}

/* process a block of data received from the device
 */
void gigaset_m10x_input(struct inbuf_t *inbuf)
{
	struct cardstate *cs;
	unsigned tail, head, numbytes;
	unsigned char *src, c;
	int procbytes;

	head = atomic_read(&inbuf->head);
	tail = atomic_read(&inbuf->tail);
	gig_dbg(DEBUG_INTR, "buffer state: %u -> %u", head, tail);

	if (head != tail) {
		cs = inbuf->cs;
		src = inbuf->data + head;
		numbytes = (head > tail ? RBUFSIZE : tail) - head;
		gig_dbg(DEBUG_INTR, "processing %u bytes", numbytes);

		while (numbytes) {
			if (atomic_read(&cs->mstate) == MS_LOCKED) {
				procbytes = lock_loop(src, numbytes, inbuf);
				src += procbytes;
				numbytes -= procbytes;
			} else {
				c = *src++;
				--numbytes;
				if (c == DLE_FLAG && (cs->dle ||
				    inbuf->inputstate & INS_DLE_command)) {
					if (!(inbuf->inputstate & INS_DLE_char)) {
						inbuf->inputstate |= INS_DLE_char;
						goto nextbyte;
					}
					/* <DLE> <DLE> => <DLE> in data stream */
					inbuf->inputstate &= ~INS_DLE_char;
				}

				if (!(inbuf->inputstate & INS_DLE_char)) {

					/* FIXME use function pointers?  */
					if (inbuf->inputstate & INS_command)
						procbytes = cmd_loop(c, src, numbytes, inbuf);
					else if (inbuf->bcs->proto2 == ISDN_PROTO_L2_HDLC)
						procbytes = hdlc_loop(c, src, numbytes, inbuf);
					else
						procbytes = iraw_loop(c, src, numbytes, inbuf);

					src += procbytes;
					numbytes -= procbytes;
				} else {  /* DLE char */
					inbuf->inputstate &= ~INS_DLE_char;
					switch (c) {
					case 'X': /*begin of command*/
#ifdef CONFIG_GIGASET_DEBUG
						if (inbuf->inputstate & INS_command)
							dev_err(cs->dev,
					"received <DLE> 'X' in command mode\n");
#endif
						inbuf->inputstate |=
							INS_command | INS_DLE_command;
						break;
					case '.': /*end of command*/
#ifdef CONFIG_GIGASET_DEBUG
						if (!(inbuf->inputstate & INS_command))
							dev_err(cs->dev,
					"received <DLE> '.' in hdlc mode\n");
#endif
						inbuf->inputstate &= cs->dle ?
							~(INS_DLE_command|INS_command)
							: ~INS_DLE_command;
						break;
					//case DLE_FLAG: /*DLE_FLAG in data stream*/ /* schon oben behandelt! */
					default:
						dev_err(cs->dev,
						      "received 0x10 0x%02x!\n",
							(int) c);
						/* FIXME: reset driver?? */
					}
				}
			}
nextbyte:
			if (!numbytes) {
				/* end of buffer, check for wrap */
				if (head > tail) {
					head = 0;
					src = inbuf->data;
					numbytes = tail;
				} else {
					head = tail;
					break;
				}
			}
		}

		gig_dbg(DEBUG_INTR, "setting head to %u", head);
		atomic_set(&inbuf->head, head);
	}
}


/* == data output ========================================================== */

/* Encoding of a PPP packet into an octet stuffed HDLC frame
 * with FCS, opening and closing flags.
 * parameters:
 *	skb	skb containing original packet (freed upon return)
 *	head	number of headroom bytes to allocate in result skb
 *	tail	number of tailroom bytes to allocate in result skb
 * Return value:
 *	pointer to newly allocated skb containing the result frame
 */
static struct sk_buff *HDLC_Encode(struct sk_buff *skb, int head, int tail)
{
	struct sk_buff *hdlc_skb;
	__u16 fcs;
	unsigned char c;
	unsigned char *cp;
	int len;
	unsigned int stuf_cnt;

	stuf_cnt = 0;
	fcs = PPP_INITFCS;
	cp = skb->data;
	len = skb->len;
	while (len--) {
		if (muststuff(*cp))
			stuf_cnt++;
		fcs = crc_ccitt_byte(fcs, *cp++);
	}
	fcs ^= 0xffff;			/* complement */

	/* size of new buffer: original size + number of stuffing bytes
	 * + 2 bytes FCS + 2 stuffing bytes for FCS (if needed) + 2 flag bytes
	 */
	hdlc_skb = dev_alloc_skb(skb->len + stuf_cnt + 6 + tail + head);
	if (!hdlc_skb) {
		dev_kfree_skb(skb);
		return NULL;
	}
	skb_reserve(hdlc_skb, head);

	/* Copy acknowledge request into new skb */
	memcpy(hdlc_skb->head, skb->head, 2);

	/* Add flag sequence in front of everything.. */
	*(skb_put(hdlc_skb, 1)) = PPP_FLAG;

	/* Perform byte stuffing while copying data. */
	while (skb->len--) {
		if (muststuff(*skb->data)) {
			*(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
			*(skb_put(hdlc_skb, 1)) = (*skb->data++) ^ PPP_TRANS;
		} else
			*(skb_put(hdlc_skb, 1)) = *skb->data++;
	}

	/* Finally add FCS (byte stuffed) and flag sequence */
	c = (fcs & 0x00ff);	/* least significant byte first */
	if (muststuff(c)) {
		*(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
		c ^= PPP_TRANS;
	}
	*(skb_put(hdlc_skb, 1)) = c;

	c = ((fcs >> 8) & 0x00ff);
	if (muststuff(c)) {
		*(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
		c ^= PPP_TRANS;
	}
	*(skb_put(hdlc_skb, 1)) = c;

	*(skb_put(hdlc_skb, 1)) = PPP_FLAG;

	dev_kfree_skb(skb);
	return hdlc_skb;
}

/* Encoding of a raw packet into an octet stuffed bit inverted frame
 * parameters:
 *	skb	skb containing original packet (freed upon return)
 *	head	number of headroom bytes to allocate in result skb
 *	tail	number of tailroom bytes to allocate in result skb
 * Return value:
 *	pointer to newly allocated skb containing the result frame
 */
static struct sk_buff *iraw_encode(struct sk_buff *skb, int head, int tail)
{
	struct sk_buff *iraw_skb;
	unsigned char c;
	unsigned char *cp;
	int len;

	/* worst case: every byte must be stuffed */
	iraw_skb = dev_alloc_skb(2*skb->len + tail + head);
	if (!iraw_skb) {
		dev_kfree_skb(skb);
		return NULL;
	}
	skb_reserve(iraw_skb, head);

	cp = skb->data;
	len = skb->len;
	while (len--) {
		c = bitrev8(*cp++);
		if (c == DLE_FLAG)
			*(skb_put(iraw_skb, 1)) = c;
		*(skb_put(iraw_skb, 1)) = c;
	}
	dev_kfree_skb(skb);
	return iraw_skb;
}

/* gigaset_send_skb
 * called by common.c to queue an skb for sending
 * and start transmission if necessary
 * parameters:
 *	B Channel control structure
 *	skb
 * Return value:
 *	number of bytes accepted for sending
 *	(skb->len if ok, 0 if out of buffer space)
 *	or error code (< 0, eg. -EINVAL)
 */
int gigaset_m10x_send_skb(struct bc_state *bcs, struct sk_buff *skb)
{
	unsigned len = skb->len;
	unsigned long flags;

	if (bcs->proto2 == ISDN_PROTO_L2_HDLC)
		skb = HDLC_Encode(skb, HW_HDR_LEN, 0);
	else
		skb = iraw_encode(skb, HW_HDR_LEN, 0);
	if (!skb) {
		err("unable to allocate memory for encoding!\n");
		return -ENOMEM;
	}

	skb_queue_tail(&bcs->squeue, skb);
	spin_lock_irqsave(&bcs->cs->lock, flags);
	if (bcs->cs->connected)
		tasklet_schedule(&bcs->cs->write_tasklet);
	spin_unlock_irqrestore(&bcs->cs->lock, flags);

	return len;	/* ok so far */
}

Privacy Policy