Free Electrons

Embedded Linux Experts

  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
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
/*
 * net/tipc/bearer.c: TIPC bearer code
 *
 * Copyright (c) 1996-2006, Ericsson AB
 * Copyright (c) 2004-2006, 2010-2011, Wind River Systems
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "core.h"
#include "config.h"
#include "bearer.h"
#include "discover.h"

#define MAX_ADDR_STR 32

static struct tipc_media *media_list[MAX_MEDIA];
static u32 media_count;

struct tipc_bearer tipc_bearers[MAX_BEARERS];

static void bearer_disable(struct tipc_bearer *b_ptr);

/**
 * media_name_valid - validate media name
 *
 * Returns 1 if media name is valid, otherwise 0.
 */

static int media_name_valid(const char *name)
{
	u32 len;

	len = strlen(name);
	if ((len + 1) > TIPC_MAX_MEDIA_NAME)
		return 0;
	return strspn(name, tipc_alphabet) == len;
}

/**
 * tipc_media_find - locates specified media object by name
 */

struct tipc_media *tipc_media_find(const char *name)
{
	u32 i;

	for (i = 0; i < media_count; i++) {
		if (!strcmp(media_list[i]->name, name))
			return media_list[i];
	}
	return NULL;
}

/**
 * media_find_id - locates specified media object by type identifier
 */

static struct tipc_media *media_find_id(u8 type)
{
	u32 i;

	for (i = 0; i < media_count; i++) {
		if (media_list[i]->type_id == type)
			return media_list[i];
	}
	return NULL;
}

/**
 * tipc_register_media - register a media type
 *
 * Bearers for this media type must be activated separately at a later stage.
 */

int tipc_register_media(struct tipc_media *m_ptr)
{
	int res = -EINVAL;

	write_lock_bh(&tipc_net_lock);

	if (!media_name_valid(m_ptr->name))
		goto exit;
	if ((m_ptr->bcast_addr.media_id != m_ptr->type_id) ||
	    !m_ptr->bcast_addr.broadcast)
		goto exit;
	if (m_ptr->priority > TIPC_MAX_LINK_PRI)
		goto exit;
	if ((m_ptr->tolerance < TIPC_MIN_LINK_TOL) ||
	    (m_ptr->tolerance > TIPC_MAX_LINK_TOL))
		goto exit;
	if (media_count >= MAX_MEDIA)
		goto exit;
	if (tipc_media_find(m_ptr->name) || media_find_id(m_ptr->type_id))
		goto exit;

	media_list[media_count] = m_ptr;
	media_count++;
	res = 0;
exit:
	write_unlock_bh(&tipc_net_lock);
	if (res)
		warn("Media <%s> registration error\n", m_ptr->name);
	return res;
}

/**
 * tipc_media_addr_printf - record media address in print buffer
 */

void tipc_media_addr_printf(struct print_buf *pb, struct tipc_media_addr *a)
{
	char addr_str[MAX_ADDR_STR];
	struct tipc_media *m_ptr;

	m_ptr = media_find_id(a->media_id);

	if (m_ptr && !m_ptr->addr2str(a, addr_str, sizeof(addr_str)))
		tipc_printf(pb, "%s(%s)", m_ptr->name, addr_str);
	else {
		u32 i;

		tipc_printf(pb, "UNKNOWN(%u)", a->media_id);
		for (i = 0; i < sizeof(a->value); i++)
			tipc_printf(pb, "-%02x", a->value[i]);
	}
}

/**
 * tipc_media_get_names - record names of registered media in buffer
 */

struct sk_buff *tipc_media_get_names(void)
{
	struct sk_buff *buf;
	int i;

	buf = tipc_cfg_reply_alloc(MAX_MEDIA * TLV_SPACE(TIPC_MAX_MEDIA_NAME));
	if (!buf)
		return NULL;

	read_lock_bh(&tipc_net_lock);
	for (i = 0; i < media_count; i++) {
		tipc_cfg_append_tlv(buf, TIPC_TLV_MEDIA_NAME,
				    media_list[i]->name,
				    strlen(media_list[i]->name) + 1);
	}
	read_unlock_bh(&tipc_net_lock);
	return buf;
}

/**
 * bearer_name_validate - validate & (optionally) deconstruct bearer name
 * @name - ptr to bearer name string
 * @name_parts - ptr to area for bearer name components (or NULL if not needed)
 *
 * Returns 1 if bearer name is valid, otherwise 0.
 */

static int bearer_name_validate(const char *name,
				struct tipc_bearer_names *name_parts)
{
	char name_copy[TIPC_MAX_BEARER_NAME];
	char *media_name;
	char *if_name;
	u32 media_len;
	u32 if_len;

	/* copy bearer name & ensure length is OK */

	name_copy[TIPC_MAX_BEARER_NAME - 1] = 0;
	/* need above in case non-Posix strncpy() doesn't pad with nulls */
	strncpy(name_copy, name, TIPC_MAX_BEARER_NAME);
	if (name_copy[TIPC_MAX_BEARER_NAME - 1] != 0)
		return 0;

	/* ensure all component parts of bearer name are present */

	media_name = name_copy;
	if_name = strchr(media_name, ':');
	if (if_name == NULL)
		return 0;
	*(if_name++) = 0;
	media_len = if_name - media_name;
	if_len = strlen(if_name) + 1;

	/* validate component parts of bearer name */

	if ((media_len <= 1) || (media_len > TIPC_MAX_MEDIA_NAME) ||
	    (if_len <= 1) || (if_len > TIPC_MAX_IF_NAME) ||
	    (strspn(media_name, tipc_alphabet) != (media_len - 1)) ||
	    (strspn(if_name, tipc_alphabet) != (if_len - 1)))
		return 0;

	/* return bearer name components, if necessary */

	if (name_parts) {
		strcpy(name_parts->media_name, media_name);
		strcpy(name_parts->if_name, if_name);
	}
	return 1;
}

/**
 * tipc_bearer_find - locates bearer object with matching bearer name
 */

struct tipc_bearer *tipc_bearer_find(const char *name)
{
	struct tipc_bearer *b_ptr;
	u32 i;

	for (i = 0, b_ptr = tipc_bearers; i < MAX_BEARERS; i++, b_ptr++) {
		if (b_ptr->active && (!strcmp(b_ptr->name, name)))
			return b_ptr;
	}
	return NULL;
}

/**
 * tipc_bearer_find_interface - locates bearer object with matching interface name
 */

struct tipc_bearer *tipc_bearer_find_interface(const char *if_name)
{
	struct tipc_bearer *b_ptr;
	char *b_if_name;
	u32 i;

	for (i = 0, b_ptr = tipc_bearers; i < MAX_BEARERS; i++, b_ptr++) {
		if (!b_ptr->active)
			continue;
		b_if_name = strchr(b_ptr->name, ':') + 1;
		if (!strcmp(b_if_name, if_name))
			return b_ptr;
	}
	return NULL;
}

/**
 * tipc_bearer_get_names - record names of bearers in buffer
 */

struct sk_buff *tipc_bearer_get_names(void)
{
	struct sk_buff *buf;
	struct tipc_bearer *b_ptr;
	int i, j;

	buf = tipc_cfg_reply_alloc(MAX_BEARERS * TLV_SPACE(TIPC_MAX_BEARER_NAME));
	if (!buf)
		return NULL;

	read_lock_bh(&tipc_net_lock);
	for (i = 0; i < media_count; i++) {
		for (j = 0; j < MAX_BEARERS; j++) {
			b_ptr = &tipc_bearers[j];
			if (b_ptr->active && (b_ptr->media == media_list[i])) {
				tipc_cfg_append_tlv(buf, TIPC_TLV_BEARER_NAME,
						    b_ptr->name,
						    strlen(b_ptr->name) + 1);
			}
		}
	}
	read_unlock_bh(&tipc_net_lock);
	return buf;
}

void tipc_bearer_add_dest(struct tipc_bearer *b_ptr, u32 dest)
{
	tipc_nmap_add(&b_ptr->nodes, dest);
	tipc_bcbearer_sort();
	tipc_disc_add_dest(b_ptr->link_req);
}

void tipc_bearer_remove_dest(struct tipc_bearer *b_ptr, u32 dest)
{
	tipc_nmap_remove(&b_ptr->nodes, dest);
	tipc_bcbearer_sort();
	tipc_disc_remove_dest(b_ptr->link_req);
}

/*
 * bearer_push(): Resolve bearer congestion. Force the waiting
 * links to push out their unsent packets, one packet per link
 * per iteration, until all packets are gone or congestion reoccurs.
 * 'tipc_net_lock' is read_locked when this function is called
 * bearer.lock must be taken before calling
 * Returns binary true(1) ore false(0)
 */
static int bearer_push(struct tipc_bearer *b_ptr)
{
	u32 res = 0;
	struct tipc_link *ln, *tln;

	if (b_ptr->blocked)
		return 0;

	while (!list_empty(&b_ptr->cong_links) && (res != PUSH_FAILED)) {
		list_for_each_entry_safe(ln, tln, &b_ptr->cong_links, link_list) {
			res = tipc_link_push_packet(ln);
			if (res == PUSH_FAILED)
				break;
			if (res == PUSH_FINISHED)
				list_move_tail(&ln->link_list, &b_ptr->links);
		}
	}
	return list_empty(&b_ptr->cong_links);
}

void tipc_bearer_lock_push(struct tipc_bearer *b_ptr)
{
	spin_lock_bh(&b_ptr->lock);
	bearer_push(b_ptr);
	spin_unlock_bh(&b_ptr->lock);
}


/*
 * Interrupt enabling new requests after bearer congestion or blocking:
 * See bearer_send().
 */
void tipc_continue(struct tipc_bearer *b_ptr)
{
	spin_lock_bh(&b_ptr->lock);
	if (!list_empty(&b_ptr->cong_links))
		tipc_k_signal((Handler)tipc_bearer_lock_push, (unsigned long)b_ptr);
	b_ptr->blocked = 0;
	spin_unlock_bh(&b_ptr->lock);
}

/*
 * Schedule link for sending of messages after the bearer
 * has been deblocked by 'continue()'. This method is called
 * when somebody tries to send a message via this link while
 * the bearer is congested. 'tipc_net_lock' is in read_lock here
 * bearer.lock is busy
 */

static void tipc_bearer_schedule_unlocked(struct tipc_bearer *b_ptr,
						struct tipc_link *l_ptr)
{
	list_move_tail(&l_ptr->link_list, &b_ptr->cong_links);
}

/*
 * Schedule link for sending of messages after the bearer
 * has been deblocked by 'continue()'. This method is called
 * when somebody tries to send a message via this link while
 * the bearer is congested. 'tipc_net_lock' is in read_lock here,
 * bearer.lock is free
 */

void tipc_bearer_schedule(struct tipc_bearer *b_ptr, struct tipc_link *l_ptr)
{
	spin_lock_bh(&b_ptr->lock);
	tipc_bearer_schedule_unlocked(b_ptr, l_ptr);
	spin_unlock_bh(&b_ptr->lock);
}


/*
 * tipc_bearer_resolve_congestion(): Check if there is bearer congestion,
 * and if there is, try to resolve it before returning.
 * 'tipc_net_lock' is read_locked when this function is called
 */
int tipc_bearer_resolve_congestion(struct tipc_bearer *b_ptr,
					struct tipc_link *l_ptr)
{
	int res = 1;

	if (list_empty(&b_ptr->cong_links))
		return 1;
	spin_lock_bh(&b_ptr->lock);
	if (!bearer_push(b_ptr)) {
		tipc_bearer_schedule_unlocked(b_ptr, l_ptr);
		res = 0;
	}
	spin_unlock_bh(&b_ptr->lock);
	return res;
}

/**
 * tipc_bearer_congested - determines if bearer is currently congested
 */

int tipc_bearer_congested(struct tipc_bearer *b_ptr, struct tipc_link *l_ptr)
{
	if (unlikely(b_ptr->blocked))
		return 1;
	if (likely(list_empty(&b_ptr->cong_links)))
		return 0;
	return !tipc_bearer_resolve_congestion(b_ptr, l_ptr);
}

/**
 * tipc_enable_bearer - enable bearer with the given name
 */

int tipc_enable_bearer(const char *name, u32 disc_domain, u32 priority)
{
	struct tipc_bearer *b_ptr;
	struct tipc_media *m_ptr;
	struct tipc_bearer_names b_names;
	char addr_string[16];
	u32 bearer_id;
	u32 with_this_prio;
	u32 i;
	int res = -EINVAL;

	if (!tipc_own_addr) {
		warn("Bearer <%s> rejected, not supported in standalone mode\n",
		     name);
		return -ENOPROTOOPT;
	}
	if (!bearer_name_validate(name, &b_names)) {
		warn("Bearer <%s> rejected, illegal name\n", name);
		return -EINVAL;
	}
	if (tipc_addr_domain_valid(disc_domain) &&
	    (disc_domain != tipc_own_addr)) {
		if (tipc_in_scope(disc_domain, tipc_own_addr)) {
			disc_domain = tipc_own_addr & TIPC_CLUSTER_MASK;
			res = 0;   /* accept any node in own cluster */
		} else if (in_own_cluster(disc_domain))
			res = 0;   /* accept specified node in own cluster */
	}
	if (res) {
		warn("Bearer <%s> rejected, illegal discovery domain\n", name);
		return -EINVAL;
	}
	if ((priority > TIPC_MAX_LINK_PRI) &&
	    (priority != TIPC_MEDIA_LINK_PRI)) {
		warn("Bearer <%s> rejected, illegal priority\n", name);
		return -EINVAL;
	}

	write_lock_bh(&tipc_net_lock);

	m_ptr = tipc_media_find(b_names.media_name);
	if (!m_ptr) {
		warn("Bearer <%s> rejected, media <%s> not registered\n", name,
		     b_names.media_name);
		goto exit;
	}

	if (priority == TIPC_MEDIA_LINK_PRI)
		priority = m_ptr->priority;

restart:
	bearer_id = MAX_BEARERS;
	with_this_prio = 1;
	for (i = MAX_BEARERS; i-- != 0; ) {
		if (!tipc_bearers[i].active) {
			bearer_id = i;
			continue;
		}
		if (!strcmp(name, tipc_bearers[i].name)) {
			warn("Bearer <%s> rejected, already enabled\n", name);
			goto exit;
		}
		if ((tipc_bearers[i].priority == priority) &&
		    (++with_this_prio > 2)) {
			if (priority-- == 0) {
				warn("Bearer <%s> rejected, duplicate priority\n",
				     name);
				goto exit;
			}
			warn("Bearer <%s> priority adjustment required %u->%u\n",
			     name, priority + 1, priority);
			goto restart;
		}
	}
	if (bearer_id >= MAX_BEARERS) {
		warn("Bearer <%s> rejected, bearer limit reached (%u)\n",
		     name, MAX_BEARERS);
		goto exit;
	}

	b_ptr = &tipc_bearers[bearer_id];
	strcpy(b_ptr->name, name);
	res = m_ptr->enable_bearer(b_ptr);
	if (res) {
		warn("Bearer <%s> rejected, enable failure (%d)\n", name, -res);
		goto exit;
	}

	b_ptr->identity = bearer_id;
	b_ptr->media = m_ptr;
	b_ptr->tolerance = m_ptr->tolerance;
	b_ptr->window = m_ptr->window;
	b_ptr->net_plane = bearer_id + 'A';
	b_ptr->active = 1;
	b_ptr->priority = priority;
	INIT_LIST_HEAD(&b_ptr->cong_links);
	INIT_LIST_HEAD(&b_ptr->links);
	spin_lock_init(&b_ptr->lock);

	res = tipc_disc_create(b_ptr, &m_ptr->bcast_addr, disc_domain);
	if (res) {
		bearer_disable(b_ptr);
		warn("Bearer <%s> rejected, discovery object creation failed\n",
		     name);
		goto exit;
	}
	info("Enabled bearer <%s>, discovery domain %s, priority %u\n",
	     name, tipc_addr_string_fill(addr_string, disc_domain), priority);
exit:
	write_unlock_bh(&tipc_net_lock);
	return res;
}

/**
 * tipc_block_bearer(): Block the bearer with the given name,
 *                      and reset all its links
 */

int tipc_block_bearer(const char *name)
{
	struct tipc_bearer *b_ptr = NULL;
	struct tipc_link *l_ptr;
	struct tipc_link *temp_l_ptr;

	read_lock_bh(&tipc_net_lock);
	b_ptr = tipc_bearer_find(name);
	if (!b_ptr) {
		warn("Attempt to block unknown bearer <%s>\n", name);
		read_unlock_bh(&tipc_net_lock);
		return -EINVAL;
	}

	info("Blocking bearer <%s>\n", name);
	spin_lock_bh(&b_ptr->lock);
	b_ptr->blocked = 1;
	list_splice_init(&b_ptr->cong_links, &b_ptr->links);
	list_for_each_entry_safe(l_ptr, temp_l_ptr, &b_ptr->links, link_list) {
		struct tipc_node *n_ptr = l_ptr->owner;

		spin_lock_bh(&n_ptr->lock);
		tipc_link_reset(l_ptr);
		spin_unlock_bh(&n_ptr->lock);
	}
	spin_unlock_bh(&b_ptr->lock);
	read_unlock_bh(&tipc_net_lock);
	return 0;
}

/**
 * bearer_disable -
 *
 * Note: This routine assumes caller holds tipc_net_lock.
 */

static void bearer_disable(struct tipc_bearer *b_ptr)
{
	struct tipc_link *l_ptr;
	struct tipc_link *temp_l_ptr;

	info("Disabling bearer <%s>\n", b_ptr->name);
	spin_lock_bh(&b_ptr->lock);
	b_ptr->blocked = 1;
	b_ptr->media->disable_bearer(b_ptr);
	list_splice_init(&b_ptr->cong_links, &b_ptr->links);
	list_for_each_entry_safe(l_ptr, temp_l_ptr, &b_ptr->links, link_list) {
		tipc_link_delete(l_ptr);
	}
	if (b_ptr->link_req)
		tipc_disc_delete(b_ptr->link_req);
	spin_unlock_bh(&b_ptr->lock);
	memset(b_ptr, 0, sizeof(struct tipc_bearer));
}

int tipc_disable_bearer(const char *name)
{
	struct tipc_bearer *b_ptr;
	int res;

	write_lock_bh(&tipc_net_lock);
	b_ptr = tipc_bearer_find(name);
	if (b_ptr == NULL) {
		warn("Attempt to disable unknown bearer <%s>\n", name);
		res = -EINVAL;
	} else {
		bearer_disable(b_ptr);
		res = 0;
	}
	write_unlock_bh(&tipc_net_lock);
	return res;
}



void tipc_bearer_stop(void)
{
	u32 i;

	for (i = 0; i < MAX_BEARERS; i++) {
		if (tipc_bearers[i].active)
			bearer_disable(&tipc_bearers[i]);
	}
	media_count = 0;
}