aboutsummaryrefslogtreecommitdiffstats
path: root/net/irda/irlmp_frame.c
blob: 559302d3fe66264611100da2352010ebe0580897 (plain) (blame)
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
/*********************************************************************
 *
 * Filename:      irlmp_frame.c
 * Version:       0.9
 * Description:   IrLMP frame implementation
 * Status:        Experimental.
 * Author:        Dag Brattli <dagb@cs.uit.no>
 * Created at:    Tue Aug 19 02:09:59 1997
 * Modified at:   Mon Dec 13 13:41:12 1999
 * Modified by:   Dag Brattli <dagb@cs.uit.no>
 *
 *     Copyright (c) 1998-1999 Dag Brattli <dagb@cs.uit.no>
 *     All Rights Reserved.
 *     Copyright (c) 2000-2003 Jean Tourrilhes <jt@hpl.hp.com>
 *
 *     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.
 *
 *     Neither Dag Brattli nor University of Troms� admit liability nor
 *     provide warranty for any of this software. This material is
 *     provided "AS-IS" and at no charge.
 *
 ********************************************************************/

#include <linux/skbuff.h>
#include <linux/kernel.h>

#include <net/irda/irda.h>
#include <net/irda/irlap.h>
#include <net/irda/timer.h>
#include <net/irda/irlmp.h>
#include <net/irda/irlmp_frame.h>
#include <net/irda/discovery.h>

static struct lsap_cb *irlmp_find_lsap(struct lap_cb *self, __u8 dlsap,
				       __u8 slsap, int status, hashbin_t *);

inline void irlmp_send_data_pdu(struct lap_cb *self, __u8 dlsap, __u8 slsap,
				int expedited, struct sk_buff *skb)
{
	skb->data[0] = dlsap;
	skb->data[1] = slsap;

	if (expedited) {
		IRDA_DEBUG(4, "%s(), sending expedited data\n", __FUNCTION__);
		irlap_data_request(self->irlap, skb, TRUE);
	} else
		irlap_data_request(self->irlap, skb, FALSE);
}

/*
 * Function irlmp_send_lcf_pdu (dlsap, slsap, opcode,skb)
 *
 *    Send Link Control Frame to IrLAP
 */
void irlmp_send_lcf_pdu(struct lap_cb *self, __u8 dlsap, __u8 slsap,
			__u8 opcode, struct sk_buff *skb)
{
	__u8 *frame;

	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
	IRDA_ASSERT(skb != NULL, return;);

	frame = skb->data;

	frame[0] = dlsap | CONTROL_BIT;
	frame[1] = slsap;

	frame[2] = opcode;

	if (opcode == DISCONNECT)
		frame[3] = 0x01; /* Service user request */
	else
		frame[3] = 0x00; /* rsvd */

	irlap_data_request(self->irlap, skb, FALSE);
}

/*
 * Function irlmp_input (skb)
 *
 *    Used by IrLAP to pass received data frames to IrLMP layer
 *
 */
void irlmp_link_data_indication(struct lap_cb *self, struct sk_buff *skb,
				int unreliable)
{
	struct lsap_cb *lsap;
	__u8   slsap_sel;   /* Source (this) LSAP address */
	__u8   dlsap_sel;   /* Destination LSAP address */
	__u8   *fp;

	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
	IRDA_ASSERT(skb->len > 2, return;);

	fp = skb->data;

	/*
	 *  The next statements may be confusing, but we do this so that
	 *  destination LSAP of received frame is source LSAP in our view
	 */
	slsap_sel = fp[0] & LSAP_MASK;
	dlsap_sel = fp[1];

	/*
	 *  Check if this is an incoming connection, since we must deal with
	 *  it in a different way than other established connections.
	 */
	if ((fp[0] & CONTROL_BIT) && (fp[2] == CONNECT_CMD)) {
		IRDA_DEBUG(3, "%s(), incoming connection, "
			   "source LSAP=%d, dest LSAP=%d\n",
			   __FUNCTION__, slsap_sel, dlsap_sel);

		/* Try to find LSAP among the unconnected LSAPs */
		lsap = irlmp_find_lsap(self, dlsap_sel, slsap_sel, CONNECT_CMD,
				       irlmp->unconnected_lsaps);

		/* Maybe LSAP was already connected, so try one more time */
		if (!lsap) {
			IRDA_DEBUG(1, "%s(), incoming connection for LSAP already connected\n", __FUNCTION__);
			lsap = irlmp_find_lsap(self, dlsap_sel, slsap_sel, 0,
					       self->lsaps);
		}
	} else
		lsap = irlmp_find_lsap(self, dlsap_sel, slsap_sel, 0,
				       self->lsaps);

	if (lsap == NULL) {
		IRDA_DEBUG(2, "IrLMP, Sorry, no LSAP for received frame!\n");
		IRDA_DEBUG(2, "%s(), slsap_sel = %02x, dlsap_sel = %02x\n",
			   __FUNCTION__, slsap_sel, dlsap_sel);
		if (fp[0] & CONTROL_BIT) {
			IRDA_DEBUG(2, "%s(), received control frame %02x\n",
				   __FUNCTION__, fp[2]);
		} else {
			IRDA_DEBUG(2, "%s(), received data frame\n", __FUNCTION__);
		}
		return;
	}

	/*
	 *  Check if we received a control frame?
	 */
	if (fp[0] & CONTROL_BIT) {
		switch (fp[2]) {
		case CONNECT_CMD:
			lsap->lap = self;
			irlmp_do_lsap_event(lsap, LM_CONNECT_INDICATION, skb);
			break;
		case CONNECT_CNF:
			irlmp_do_lsap_event(lsap, LM_CONNECT_CONFIRM, skb);
			break;
		case DISCONNECT:
			IRDA_DEBUG(4, "%s(), Disconnect indication!\n",
				   __FUNCTION__);
			irlmp_do_lsap_event(lsap, LM_DISCONNECT_INDICATION,
					    skb);
			break;
		case ACCESSMODE_CMD:
			IRDA_DEBUG(0, "Access mode cmd not implemented!\n");
			break;
		case ACCESSMODE_CNF:
			IRDA_DEBUG(0, "Access mode cnf not implemented!\n");
			break;
		default:
			IRDA_DEBUG(0, "%s(), Unknown control frame %02x\n",
				   __FUNCTION__, fp[2]);
			break;
		}
	} else if (unreliable) {
		/* Optimize and bypass the state machine if possible */
		if (lsap->lsap_state == LSAP_DATA_TRANSFER_READY)
			irlmp_udata_indication(lsap, skb);
		else
			irlmp_do_lsap_event(lsap, LM_UDATA_INDICATION, skb);
	} else {
		/* Optimize and bypass the state machine if possible */
		if (lsap->lsap_state == LSAP_DATA_TRANSFER_READY)
			irlmp_data_indication(lsap, skb);
		else
			irlmp_do_lsap_event(lsap, LM_DATA_INDICATION, skb);
	}
}

/*
 * Function irlmp_link_unitdata_indication (self, skb)
 *
 *
 *
 */
#ifdef CONFIG_IRDA_ULTRA
void irlmp_link_unitdata_indication(struct lap_cb *self, struct sk_buff *skb)
{
	struct lsap_cb *lsap;
	__u8   slsap_sel;   /* Source (this) LSAP address */
	__u8   dlsap_sel;   /* Destination LSAP address */
	__u8   pid;         /* Protocol identifier */
	__u8   *fp;
	unsigned long flags;

	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
	IRDA_ASSERT(skb->len > 2, return;);

	fp = skb->data;

	/*
	 *  The next statements may be confusing, but we do this so that
	 *  destination LSAP of received frame is source LSAP in our view
	 */
	slsap_sel = fp[0] & LSAP_MASK;
	dlsap_sel = fp[1];
	pid       = fp[2];

	if (pid & 0x80) {
		IRDA_DEBUG(0, "%s(), extension in PID not supp!\n",
			   __FUNCTION__);
		return;
	}

	/* Check if frame is addressed to the connectionless LSAP */
	if ((slsap_sel != LSAP_CONNLESS) || (dlsap_sel != LSAP_CONNLESS)) {
		IRDA_DEBUG(0, "%s(), dropping frame!\n", __FUNCTION__);
		return;
	}

	/* Search the connectionless LSAP */
	spin_lock_irqsave(&irlmp->unconnected_lsaps->hb_spinlock, flags);
	lsap = (struct lsap_cb *) hashbin_get_first(irlmp->unconnected_lsaps);
	while (lsap != NULL) {
		/*
		 *  Check if source LSAP and dest LSAP selectors and PID match.
		 */
		if ((lsap->slsap_sel == slsap_sel) &&
		    (lsap->dlsap_sel == dlsap_sel) &&
		    (lsap->pid == pid))
		{
			break;
		}
		lsap = (struct lsap_cb *) hashbin_get_next(irlmp->unconnected_lsaps);
	}
	spin_unlock_irqrestore(&irlmp->unconnected_lsaps->hb_spinlock, flags);

	if (lsap)
		irlmp_connless_data_indication(lsap, skb);
	else {
		IRDA_DEBUG(0, "%s(), found no matching LSAP!\n", __FUNCTION__);
	}
}
#endif /* CONFIG_IRDA_ULTRA */

/*
 * Function irlmp_link_disconnect_indication (reason, userdata)
 *
 *    IrLAP has disconnected
 *
 */
void irlmp_link_disconnect_indication(struct lap_cb *lap,
				      struct irlap_cb *irlap,
				      LAP_REASON reason,
				      struct sk_buff *skb)
{
	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(lap != NULL, return;);
	IRDA_ASSERT(lap->magic == LMP_LAP_MAGIC, return;);

	lap->reason = reason;
	lap->daddr = DEV_ADDR_ANY;

	/* FIXME: must do something with the skb if any */

	/*
	 *  Inform station state machine
	 */
	irlmp_do_lap_event(lap, LM_LAP_DISCONNECT_INDICATION, NULL);
}

/*
 * Function irlmp_link_connect_indication (qos)
 *
 *    Incoming LAP connection!
 *
 */
void irlmp_link_connect_indication(struct lap_cb *self, __u32 saddr,
				   __u32 daddr, struct qos_info *qos,
				   struct sk_buff *skb)
{
	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

	/* Copy QoS settings for this session */
	self->qos = qos;

	/* Update destination device address */
	self->daddr = daddr;
	IRDA_ASSERT(self->saddr == saddr, return;);

	irlmp_do_lap_event(self, LM_LAP_CONNECT_INDICATION, skb);
}

/*
 * Function irlmp_link_connect_confirm (qos)
 *
 *    LAP connection confirmed!
 *
 */
void irlmp_link_connect_confirm(struct lap_cb *self, struct qos_info *qos,
				struct sk_buff *skb)
{
	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);
	IRDA_ASSERT(qos != NULL, return;);

	/* Don't need use the skb for now */

	/* Copy QoS settings for this session */
	self->qos = qos;

	irlmp_do_lap_event(self, LM_LAP_CONNECT_CONFIRM, NULL);
}

/*
 * Function irlmp_link_discovery_indication (self, log)
 *
 *    Device is discovering us
 *
 * It's not an answer to our own discoveries, just another device trying
 * to perform discovery, but we don't want to miss the opportunity
 * to exploit this information, because :
 *	o We may not actively perform discovery (just passive discovery)
 *	o This type of discovery is much more reliable. In some cases, it
 *	  seem that less than 50% of our discoveries get an answer, while
 *	  we always get ~100% of these.
 *	o Make faster discovery, statistically divide time of discovery
 *	  events by 2 (important for the latency aspect and user feel)
 *	o Even is we do active discovery, the other node might not
 *	  answer our discoveries (ex: Palm). The Palm will just perform
 *	  one active discovery and connect directly to us.
 *
 * However, when both devices discover each other, they might attempt to
 * connect to each other following the discovery event, and it would create
 * collisions on the medium (SNRM battle).
 * The "fix" for that is to disable all connection requests in IrLAP
 * for 100ms after a discovery indication by setting the media_busy flag.
 * Previously, we used to postpone the event which was quite ugly. Now
 * that IrLAP takes care of this problem, just pass the event up...
 *
 * Jean II
 */
void irlmp_link_discovery_indication(struct lap_cb *self,
				     discovery_t *discovery)
{
	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);

	/* Add to main log, cleanup */
	irlmp_add_discovery(irlmp->cachelog, discovery);

	/* Just handle it the same way as a discovery confirm,
	 * bypass the LM_LAP state machine (see below) */
	irlmp_discovery_confirm(irlmp->cachelog, DISCOVERY_PASSIVE);
}

/*
 * Function irlmp_link_discovery_confirm (self, log)
 *
 *    Called by IrLAP with a list of discoveries after the discovery
 *    request has been carried out. A NULL log is received if IrLAP
 *    was unable to carry out the discovery request
 *
 */
void irlmp_link_discovery_confirm(struct lap_cb *self, hashbin_t *log)
{
	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LMP_LAP_MAGIC, return;);

	/* Add to main log, cleanup */
	irlmp_add_discovery_log(irlmp->cachelog, log);

	/* Propagate event to various LSAPs registered for it.
	 * We bypass the LM_LAP state machine because
	 *	1) We do it regardless of the LM_LAP state
	 *	2) It doesn't affect the LM_LAP state
	 *	3) Faster, slimer, simpler, ...
	 * Jean II */
	irlmp_discovery_confirm(irlmp->cachelog, DISCOVERY_ACTIVE);
}

#ifdef CONFIG_IRDA_CACHE_LAST_LSAP
static inline void irlmp_update_cache(struct lap_cb *lap,
				      struct lsap_cb *lsap)
{
	/* Prevent concurrent read to get garbage */
	lap->cache.valid = FALSE;
	/* Update cache entry */
	lap->cache.dlsap_sel = lsap->dlsap_sel;
	lap->cache.slsap_sel = lsap->slsap_sel;
	lap->cache.lsap = lsap;
	lap->cache.valid = TRUE;
}
#endif

/*
 * Function irlmp_find_handle (self, dlsap_sel, slsap_sel, status, queue)
 *
 *    Find handle associated with destination and source LSAP
 *
 * Any IrDA connection (LSAP/TSAP) is uniquely identified by
 * 3 parameters, the local lsap, the remote lsap and the remote address.
 * We may initiate multiple connections to the same remote service
 * (they will have different local lsap), a remote device may initiate
 * multiple connections to the same local service (they will have
 * different remote lsap), or multiple devices may connect to the same
 * service and may use the same remote lsap (and they will have
 * different remote address).
 * So, where is the remote address ? Each LAP connection is made with
 * a single remote device, so imply a specific remote address.
 * Jean II
 */
static struct lsap_cb *irlmp_find_lsap(struct lap_cb *self, __u8 dlsap_sel,
				       __u8 slsap_sel, int status,
				       hashbin_t *queue)
{
	struct lsap_cb *lsap;
	unsigned long flags;

	/*
	 *  Optimize for the common case. We assume that the last frame
	 *  received is in the same connection as the last one, so check in
	 *  cache first to avoid the linear search
	 */
#ifdef CONFIG_IRDA_CACHE_LAST_LSAP
	if ((self->cache.valid) &&
	    (self->cache.slsap_sel == slsap_sel) &&
	    (self->cache.dlsap_sel == dlsap_sel))
	{
		return (self->cache.lsap);
	}
#endif

	spin_lock_irqsave(&queue->hb_spinlock, flags);

	lsap = (struct lsap_cb *) hashbin_get_first(queue);
	while (lsap != NULL) {
		/*
		 *  If this is an incoming connection, then the destination
		 *  LSAP selector may have been specified as LM_ANY so that
		 *  any client can connect. In that case we only need to check
		 *  if the source LSAP (in our view!) match!
		 */
		if ((status == CONNECT_CMD) &&
		    (lsap->slsap_sel == slsap_sel) &&
		    (lsap->dlsap_sel == LSAP_ANY)) {
			/* This is where the dest lsap sel is set on incoming
			 * lsaps */
			lsap->dlsap_sel = dlsap_sel;
			break;
		}
		/*
		 *  Check if source LSAP and dest LSAP selectors match.
		 */
		if ((lsap->slsap_sel == slsap_sel) &&
		    (lsap->dlsap_sel == dlsap_sel))
			break;

		lsap = (struct lsap_cb *) hashbin_get_next(queue);
	}
#ifdef CONFIG_IRDA_CACHE_LAST_LSAP
	if(lsap)
		irlmp_update_cache(self, lsap);
#endif
	spin_unlock_irqrestore(&queue->hb_spinlock, flags);

	/* Return what we've found or NULL */
	return lsap;
}