summaryrefslogtreecommitdiffstats
path: root/net/tipc/node.c
blob: 20d98c56e152685a5ab84e584e9a31a33cb1bfec (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
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
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
/*
 * net/tipc/node.c: TIPC node management routines
 *
 * Copyright (c) 2000-2006, Ericsson AB
 * Copyright (c) 2005-2006, 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 "node.h"
#include "cluster.h"
#include "net.h"
#include "addr.h"
#include "node_subscr.h"
#include "link.h"
#include "port.h"
#include "bearer.h"
#include "name_distr.h"

void node_print(struct print_buf *buf, struct tipc_node *n_ptr, char *str);
static void node_lost_contact(struct tipc_node *n_ptr);
static void node_established_contact(struct tipc_node *n_ptr);

struct tipc_node *tipc_nodes = NULL;	/* sorted list of nodes within cluster */

static DEFINE_SPINLOCK(node_create_lock);

u32 tipc_own_tag = 0;

/**
 * tipc_node_create - create neighboring node
 *
 * Currently, this routine is called by neighbor discovery code, which holds
 * net_lock for reading only.  We must take node_create_lock to ensure a node
 * isn't created twice if two different bearers discover the node at the same
 * time.  (It would be preferable to switch to holding net_lock in write mode,
 * but this is a non-trivial change.)
 */

struct tipc_node *tipc_node_create(u32 addr)
{
	struct cluster *c_ptr;
	struct tipc_node *n_ptr;
	struct tipc_node **curr_node;

	spin_lock_bh(&node_create_lock);

	for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
		if (addr < n_ptr->addr)
			break;
		if (addr == n_ptr->addr) {
			spin_unlock_bh(&node_create_lock);
			return n_ptr;
		}
	}

	n_ptr = kzalloc(sizeof(*n_ptr),GFP_ATOMIC);
	if (!n_ptr) {
		spin_unlock_bh(&node_create_lock);
		warn("Node creation failed, no memory\n");
		return NULL;
	}

	c_ptr = tipc_cltr_find(addr);
	if (!c_ptr) {
		c_ptr = tipc_cltr_create(addr);
	}
	if (!c_ptr) {
		spin_unlock_bh(&node_create_lock);
		kfree(n_ptr);
		return NULL;
	}

	n_ptr->addr = addr;
		spin_lock_init(&n_ptr->lock);
	INIT_LIST_HEAD(&n_ptr->nsub);
	n_ptr->owner = c_ptr;
	tipc_cltr_attach_node(c_ptr, n_ptr);
	n_ptr->last_router = -1;

	/* Insert node into ordered list */
	for (curr_node = &tipc_nodes; *curr_node;
	     curr_node = &(*curr_node)->next) {
		if (addr < (*curr_node)->addr) {
			n_ptr->next = *curr_node;
			break;
		}
	}
	(*curr_node) = n_ptr;
	spin_unlock_bh(&node_create_lock);
	return n_ptr;
}

void tipc_node_delete(struct tipc_node *n_ptr)
{
	if (!n_ptr)
		return;

#if 0
	/* Not needed because links are already deleted via tipc_bearer_stop() */

	u32 l_num;

	for (l_num = 0; l_num < MAX_BEARERS; l_num++) {
		link_delete(n_ptr->links[l_num]);
	}
#endif

	dbg("node %x deleted\n", n_ptr->addr);
	kfree(n_ptr);
}


/**
 * tipc_node_link_up - handle addition of link
 *
 * Link becomes active (alone or shared) or standby, depending on its priority.
 */

void tipc_node_link_up(struct tipc_node *n_ptr, struct link *l_ptr)
{
	struct link **active = &n_ptr->active_links[0];

	n_ptr->working_links++;

	info("Established link <%s> on network plane %c\n",
	     l_ptr->name, l_ptr->b_ptr->net_plane);

	if (!active[0]) {
		dbg(" link %x into %x/%x\n", l_ptr, &active[0], &active[1]);
		active[0] = active[1] = l_ptr;
		node_established_contact(n_ptr);
		return;
	}
	if (l_ptr->priority < active[0]->priority) {
		info("New link <%s> becomes standby\n", l_ptr->name);
		return;
	}
	tipc_link_send_duplicate(active[0], l_ptr);
	if (l_ptr->priority == active[0]->priority) {
		active[0] = l_ptr;
		return;
	}
	info("Old link <%s> becomes standby\n", active[0]->name);
	if (active[1] != active[0])
		info("Old link <%s> becomes standby\n", active[1]->name);
	active[0] = active[1] = l_ptr;
}

/**
 * node_select_active_links - select active link
 */

static void node_select_active_links(struct tipc_node *n_ptr)
{
	struct link **active = &n_ptr->active_links[0];
	u32 i;
	u32 highest_prio = 0;

	active[0] = active[1] = NULL;

	for (i = 0; i < MAX_BEARERS; i++) {
		struct link *l_ptr = n_ptr->links[i];

		if (!l_ptr || !tipc_link_is_up(l_ptr) ||
		    (l_ptr->priority < highest_prio))
			continue;

		if (l_ptr->priority > highest_prio) {
			highest_prio = l_ptr->priority;
			active[0] = active[1] = l_ptr;
		} else {
			active[1] = l_ptr;
		}
	}
}

/**
 * tipc_node_link_down - handle loss of link
 */

void tipc_node_link_down(struct tipc_node *n_ptr, struct link *l_ptr)
{
	struct link **active;

	n_ptr->working_links--;

	if (!tipc_link_is_active(l_ptr)) {
		info("Lost standby link <%s> on network plane %c\n",
		     l_ptr->name, l_ptr->b_ptr->net_plane);
		return;
	}
	info("Lost link <%s> on network plane %c\n",
		l_ptr->name, l_ptr->b_ptr->net_plane);

	active = &n_ptr->active_links[0];
	if (active[0] == l_ptr)
		active[0] = active[1];
	if (active[1] == l_ptr)
		active[1] = active[0];
	if (active[0] == l_ptr)
		node_select_active_links(n_ptr);
	if (tipc_node_is_up(n_ptr))
		tipc_link_changeover(l_ptr);
	else
		node_lost_contact(n_ptr);
}

int tipc_node_has_active_links(struct tipc_node *n_ptr)
{
	return (n_ptr &&
		((n_ptr->active_links[0]) || (n_ptr->active_links[1])));
}

int tipc_node_has_redundant_links(struct tipc_node *n_ptr)
{
	return (n_ptr->working_links > 1);
}

static int tipc_node_has_active_routes(struct tipc_node *n_ptr)
{
	return (n_ptr && (n_ptr->last_router >= 0));
}

int tipc_node_is_up(struct tipc_node *n_ptr)
{
	return (tipc_node_has_active_links(n_ptr) || tipc_node_has_active_routes(n_ptr));
}

struct tipc_node *tipc_node_attach_link(struct link *l_ptr)
{
	struct tipc_node *n_ptr = tipc_node_find(l_ptr->addr);

	if (!n_ptr)
		n_ptr = tipc_node_create(l_ptr->addr);
	if (n_ptr) {
		u32 bearer_id = l_ptr->b_ptr->identity;
		char addr_string[16];

		if (n_ptr->link_cnt >= 2) {
			err("Attempt to create third link to %s\n",
			    addr_string_fill(addr_string, n_ptr->addr));
			return NULL;
		}

		if (!n_ptr->links[bearer_id]) {
			n_ptr->links[bearer_id] = l_ptr;
			tipc_net.zones[tipc_zone(l_ptr->addr)]->links++;
			n_ptr->link_cnt++;
			return n_ptr;
		}
		err("Attempt to establish second link on <%s> to %s \n",
		    l_ptr->b_ptr->publ.name,
		    addr_string_fill(addr_string, l_ptr->addr));
	}
	return NULL;
}

void tipc_node_detach_link(struct tipc_node *n_ptr, struct link *l_ptr)
{
	n_ptr->links[l_ptr->b_ptr->identity] = NULL;
	tipc_net.zones[tipc_zone(l_ptr->addr)]->links--;
	n_ptr->link_cnt--;
}

/*
 * Routing table management - five cases to handle:
 *
 * 1: A link towards a zone/cluster external node comes up.
 *    => Send a multicast message updating routing tables of all
 *    system nodes within own cluster that the new destination
 *    can be reached via this node.
 *    (node.establishedContact()=>cluster.multicastNewRoute())
 *
 * 2: A link towards a slave node comes up.
 *    => Send a multicast message updating routing tables of all
 *    system nodes within own cluster that the new destination
 *    can be reached via this node.
 *    (node.establishedContact()=>cluster.multicastNewRoute())
 *    => Send a  message to the slave node about existence
 *    of all system nodes within cluster:
 *    (node.establishedContact()=>cluster.sendLocalRoutes())
 *
 * 3: A new cluster local system node becomes available.
 *    => Send message(s) to this particular node containing
 *    information about all cluster external and slave
 *     nodes which can be reached via this node.
 *    (node.establishedContact()==>network.sendExternalRoutes())
 *    (node.establishedContact()==>network.sendSlaveRoutes())
 *    => Send messages to all directly connected slave nodes
 *    containing information about the existence of the new node
 *    (node.establishedContact()=>cluster.multicastNewRoute())
 *
 * 4: The link towards a zone/cluster external node or slave
 *    node goes down.
 *    => Send a multcast message updating routing tables of all
 *    nodes within cluster that the new destination can not any
 *    longer be reached via this node.
 *    (node.lostAllLinks()=>cluster.bcastLostRoute())
 *
 * 5: A cluster local system node becomes unavailable.
 *    => Remove all references to this node from the local
 *    routing tables. Note: This is a completely node
 *    local operation.
 *    (node.lostAllLinks()=>network.removeAsRouter())
 *    => Send messages to all directly connected slave nodes
 *    containing information about loss of the node
 *    (node.establishedContact()=>cluster.multicastLostRoute())
 *
 */

static void node_established_contact(struct tipc_node *n_ptr)
{
	struct cluster *c_ptr;

	dbg("node_established_contact:-> %x\n", n_ptr->addr);
	if (!tipc_node_has_active_routes(n_ptr) && in_own_cluster(n_ptr->addr)) {
		tipc_k_signal((Handler)tipc_named_node_up, n_ptr->addr);
	}

	/* Syncronize broadcast acks */
	n_ptr->bclink.acked = tipc_bclink_get_last_sent();

	if (is_slave(tipc_own_addr))
		return;
	if (!in_own_cluster(n_ptr->addr)) {
		/* Usage case 1 (see above) */
		c_ptr = tipc_cltr_find(tipc_own_addr);
		if (!c_ptr)
			c_ptr = tipc_cltr_create(tipc_own_addr);
		if (c_ptr)
			tipc_cltr_bcast_new_route(c_ptr, n_ptr->addr, 1,
						  tipc_max_nodes);
		return;
	}

	c_ptr = n_ptr->owner;
	if (is_slave(n_ptr->addr)) {
		/* Usage case 2 (see above) */
		tipc_cltr_bcast_new_route(c_ptr, n_ptr->addr, 1, tipc_max_nodes);
		tipc_cltr_send_local_routes(c_ptr, n_ptr->addr);
		return;
	}

	if (n_ptr->bclink.supported) {
		tipc_nmap_add(&tipc_cltr_bcast_nodes, n_ptr->addr);
		if (n_ptr->addr < tipc_own_addr)
			tipc_own_tag++;
	}

	/* Case 3 (see above) */
	tipc_net_send_external_routes(n_ptr->addr);
	tipc_cltr_send_slave_routes(c_ptr, n_ptr->addr);
	tipc_cltr_bcast_new_route(c_ptr, n_ptr->addr, LOWEST_SLAVE,
				  tipc_highest_allowed_slave);
}

static void node_lost_contact(struct tipc_node *n_ptr)
{
	struct cluster *c_ptr;
	struct tipc_node_subscr *ns, *tns;
	char addr_string[16];
	u32 i;

	/* Clean up broadcast reception remains */
	n_ptr->bclink.gap_after = n_ptr->bclink.gap_to = 0;
	while (n_ptr->bclink.deferred_head) {
		struct sk_buff* buf = n_ptr->bclink.deferred_head;
		n_ptr->bclink.deferred_head = buf->next;
		buf_discard(buf);
	}
	if (n_ptr->bclink.defragm) {
		buf_discard(n_ptr->bclink.defragm);
		n_ptr->bclink.defragm = NULL;
	}
	if (in_own_cluster(n_ptr->addr) && n_ptr->bclink.supported) {
		tipc_bclink_acknowledge(n_ptr, mod(n_ptr->bclink.acked + 10000));
	}

	/* Update routing tables */
	if (is_slave(tipc_own_addr)) {
		tipc_net_remove_as_router(n_ptr->addr);
	} else {
		if (!in_own_cluster(n_ptr->addr)) {
			/* Case 4 (see above) */
			c_ptr = tipc_cltr_find(tipc_own_addr);
			tipc_cltr_bcast_lost_route(c_ptr, n_ptr->addr, 1,
						   tipc_max_nodes);
		} else {
			/* Case 5 (see above) */
			c_ptr = tipc_cltr_find(n_ptr->addr);
			if (is_slave(n_ptr->addr)) {
				tipc_cltr_bcast_lost_route(c_ptr, n_ptr->addr, 1,
							   tipc_max_nodes);
			} else {
				if (n_ptr->bclink.supported) {
					tipc_nmap_remove(&tipc_cltr_bcast_nodes,
							 n_ptr->addr);
					if (n_ptr->addr < tipc_own_addr)
						tipc_own_tag--;
				}
				tipc_net_remove_as_router(n_ptr->addr);
				tipc_cltr_bcast_lost_route(c_ptr, n_ptr->addr,
							   LOWEST_SLAVE,
							   tipc_highest_allowed_slave);
			}
		}
	}
	if (tipc_node_has_active_routes(n_ptr))
		return;

	info("Lost contact with %s\n",
	     addr_string_fill(addr_string, n_ptr->addr));

	/* Abort link changeover */
	for (i = 0; i < MAX_BEARERS; i++) {
		struct link *l_ptr = n_ptr->links[i];
		if (!l_ptr)
			continue;
		l_ptr->reset_checkpoint = l_ptr->next_in_no;
		l_ptr->exp_msg_count = 0;
		tipc_link_reset_fragments(l_ptr);
	}

	/* Notify subscribers */
	list_for_each_entry_safe(ns, tns, &n_ptr->nsub, nodesub_list) {
		ns->node = NULL;
		list_del_init(&ns->nodesub_list);
		tipc_k_signal((Handler)ns->handle_node_down,
			      (unsigned long)ns->usr_handle);
	}
}

/**
 * tipc_node_select_next_hop - find the next-hop node for a message
 *
 * Called by when cluster local lookup has failed.
 */

struct tipc_node *tipc_node_select_next_hop(u32 addr, u32 selector)
{
	struct tipc_node *n_ptr;
	u32 router_addr;

	if (!tipc_addr_domain_valid(addr))
		return NULL;

	/* Look for direct link to destination processsor */
	n_ptr = tipc_node_find(addr);
	if (n_ptr && tipc_node_has_active_links(n_ptr))
		return n_ptr;

	/* Cluster local system nodes *must* have direct links */
	if (!is_slave(addr) && in_own_cluster(addr))
		return NULL;

	/* Look for cluster local router with direct link to node */
	router_addr = tipc_node_select_router(n_ptr, selector);
	if (router_addr)
		return tipc_node_select(router_addr, selector);

	/* Slave nodes can only be accessed within own cluster via a
	   known router with direct link -- if no router was found,give up */
	if (is_slave(addr))
		return NULL;

	/* Inter zone/cluster -- find any direct link to remote cluster */
	addr = tipc_addr(tipc_zone(addr), tipc_cluster(addr), 0);
	n_ptr = tipc_net_select_remote_node(addr, selector);
	if (n_ptr && tipc_node_has_active_links(n_ptr))
		return n_ptr;

	/* Last resort -- look for any router to anywhere in remote zone */
	router_addr =  tipc_net_select_router(addr, selector);
	if (router_addr)
		return tipc_node_select(router_addr, selector);

	return NULL;
}

/**
 * tipc_node_select_router - select router to reach specified node
 *
 * Uses a deterministic and fair algorithm for selecting router node.
 */

u32 tipc_node_select_router(struct tipc_node *n_ptr, u32 ref)
{
	u32 ulim;
	u32 mask;
	u32 start;
	u32 r;

	if (!n_ptr)
		return 0;

	if (n_ptr->last_router < 0)
		return 0;
	ulim = ((n_ptr->last_router + 1) * 32) - 1;

	/* Start entry must be random */
	mask = tipc_max_nodes;
	while (mask > ulim)
		mask >>= 1;
	start = ref & mask;
	r = start;

	/* Lookup upwards with wrap-around */
	do {
		if (((n_ptr->routers[r / 32]) >> (r % 32)) & 1)
			break;
	} while (++r <= ulim);
	if (r > ulim) {
		r = 1;
		do {
			if (((n_ptr->routers[r / 32]) >> (r % 32)) & 1)
				break;
		} while (++r < start);
		assert(r != start);
	}
	assert(r && (r <= ulim));
	return tipc_addr(own_zone(), own_cluster(), r);
}

void tipc_node_add_router(struct tipc_node *n_ptr, u32 router)
{
	u32 r_num = tipc_node(router);

	n_ptr->routers[r_num / 32] =
		((1 << (r_num % 32)) | n_ptr->routers[r_num / 32]);
	n_ptr->last_router = tipc_max_nodes / 32;
	while ((--n_ptr->last_router >= 0) &&
	       !n_ptr->routers[n_ptr->last_router]);
}

void tipc_node_remove_router(struct tipc_node *n_ptr, u32 router)
{
	u32 r_num = tipc_node(router);

	if (n_ptr->last_router < 0)
		return;		/* No routes */

	n_ptr->routers[r_num / 32] =
		((~(1 << (r_num % 32))) & (n_ptr->routers[r_num / 32]));
	n_ptr->last_router = tipc_max_nodes / 32;
	while ((--n_ptr->last_router >= 0) &&
	       !n_ptr->routers[n_ptr->last_router]);

	if (!tipc_node_is_up(n_ptr))
		node_lost_contact(n_ptr);
}

#if 0
void node_print(struct print_buf *buf, struct tipc_node *n_ptr, char *str)
{
	u32 i;

	tipc_printf(buf, "\n\n%s", str);
	for (i = 0; i < MAX_BEARERS; i++) {
		if (!n_ptr->links[i])
			continue;
		tipc_printf(buf, "Links[%u]: %x, ", i, n_ptr->links[i]);
	}
	tipc_printf(buf, "Active links: [%x,%x]\n",
		    n_ptr->active_links[0], n_ptr->active_links[1]);
}
#endif

u32 tipc_available_nodes(const u32 domain)
{
	struct tipc_node *n_ptr;
	u32 cnt = 0;

	read_lock_bh(&tipc_net_lock);
	for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
		if (!in_scope(domain, n_ptr->addr))
			continue;
		if (tipc_node_is_up(n_ptr))
			cnt++;
	}
	read_unlock_bh(&tipc_net_lock);
	return cnt;
}

struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space)
{
	u32 domain;
	struct sk_buff *buf;
	struct tipc_node *n_ptr;
	struct tipc_node_info node_info;
	u32 payload_size;

	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

	domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
	if (!tipc_addr_domain_valid(domain))
		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
						   " (network address)");

	read_lock_bh(&tipc_net_lock);
	if (!tipc_nodes) {
		read_unlock_bh(&tipc_net_lock);
		return tipc_cfg_reply_none();
	}

	/* For now, get space for all other nodes
	   (will need to modify this when slave nodes are supported */

	payload_size = TLV_SPACE(sizeof(node_info)) * (tipc_max_nodes - 1);
	if (payload_size > 32768u) {
		read_unlock_bh(&tipc_net_lock);
		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
						   " (too many nodes)");
	}
	buf = tipc_cfg_reply_alloc(payload_size);
	if (!buf) {
		read_unlock_bh(&tipc_net_lock);
		return NULL;
	}

	/* Add TLVs for all nodes in scope */

	for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
		if (!in_scope(domain, n_ptr->addr))
			continue;
		node_info.addr = htonl(n_ptr->addr);
		node_info.up = htonl(tipc_node_is_up(n_ptr));
		tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
				    &node_info, sizeof(node_info));
	}

	read_unlock_bh(&tipc_net_lock);
	return buf;
}

struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
{
	u32 domain;
	struct sk_buff *buf;
	struct tipc_node *n_ptr;
	struct tipc_link_info link_info;
	u32 payload_size;

	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

	domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
	if (!tipc_addr_domain_valid(domain))
		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
						   " (network address)");

	if (tipc_mode != TIPC_NET_MODE)
		return tipc_cfg_reply_none();

	read_lock_bh(&tipc_net_lock);

	/* Get space for all unicast links + multicast link */

	payload_size = TLV_SPACE(sizeof(link_info)) *
		(tipc_net.zones[tipc_zone(tipc_own_addr)]->links + 1);
	if (payload_size > 32768u) {
		read_unlock_bh(&tipc_net_lock);
		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
						   " (too many links)");
	}
	buf = tipc_cfg_reply_alloc(payload_size);
	if (!buf) {
		read_unlock_bh(&tipc_net_lock);
		return NULL;
	}

	/* Add TLV for broadcast link */

	link_info.dest = htonl(tipc_own_addr & 0xfffff00);
	link_info.up = htonl(1);
	sprintf(link_info.str, tipc_bclink_name);
	tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));

	/* Add TLVs for any other links in scope */

	for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
		u32 i;

		if (!in_scope(domain, n_ptr->addr))
			continue;
		tipc_node_lock(n_ptr);
		for (i = 0; i < MAX_BEARERS; i++) {
			if (!n_ptr->links[i])
				continue;
			link_info.dest = htonl(n_ptr->addr);
			link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
			strcpy(link_info.str, n_ptr->links[i]->name);
			tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
					    &link_info, sizeof(link_info));
		}
		tipc_node_unlock(n_ptr);
	}

	read_unlock_bh(&tipc_net_lock);
	return buf;
}
OpenPOWER on IntegriCloud