xref: /linux/net/tipc/node.c (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
1 /*
2  * net/tipc/node.c: TIPC node management routines
3  *
4  * Copyright (c) 2000-2006, Ericsson AB
5  * Copyright (c) 2005-2006, Wind River Systems
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the names of the copyright holders nor the names of its
17  *    contributors may be used to endorse or promote products derived from
18  *    this software without specific prior written permission.
19  *
20  * Alternatively, this software may be distributed under the terms of the
21  * GNU General Public License ("GPL") version 2 as published by the Free
22  * Software Foundation.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36 
37 #include "core.h"
38 #include "config.h"
39 #include "node.h"
40 #include "cluster.h"
41 #include "net.h"
42 #include "addr.h"
43 #include "node_subscr.h"
44 #include "link.h"
45 #include "port.h"
46 #include "bearer.h"
47 #include "name_distr.h"
48 
49 void node_print(struct print_buf *buf, struct tipc_node *n_ptr, char *str);
50 static void node_lost_contact(struct tipc_node *n_ptr);
51 static void node_established_contact(struct tipc_node *n_ptr);
52 
53 struct tipc_node *tipc_nodes = NULL;	/* sorted list of nodes within cluster */
54 
55 static DEFINE_SPINLOCK(node_create_lock);
56 
57 u32 tipc_own_tag = 0;
58 
59 /**
60  * tipc_node_create - create neighboring node
61  *
62  * Currently, this routine is called by neighbor discovery code, which holds
63  * net_lock for reading only.  We must take node_create_lock to ensure a node
64  * isn't created twice if two different bearers discover the node at the same
65  * time.  (It would be preferable to switch to holding net_lock in write mode,
66  * but this is a non-trivial change.)
67  */
68 
69 struct tipc_node *tipc_node_create(u32 addr)
70 {
71 	struct cluster *c_ptr;
72 	struct tipc_node *n_ptr;
73 	struct tipc_node **curr_node;
74 
75 	spin_lock_bh(&node_create_lock);
76 
77 	for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
78 		if (addr < n_ptr->addr)
79 			break;
80 		if (addr == n_ptr->addr) {
81 			spin_unlock_bh(&node_create_lock);
82 			return n_ptr;
83 		}
84 	}
85 
86 	n_ptr = kzalloc(sizeof(*n_ptr),GFP_ATOMIC);
87 	if (!n_ptr) {
88 		spin_unlock_bh(&node_create_lock);
89 		warn("Node creation failed, no memory\n");
90 		return NULL;
91 	}
92 
93 	c_ptr = tipc_cltr_find(addr);
94 	if (!c_ptr) {
95 		c_ptr = tipc_cltr_create(addr);
96 	}
97 	if (!c_ptr) {
98 		spin_unlock_bh(&node_create_lock);
99 		kfree(n_ptr);
100 		return NULL;
101 	}
102 
103 	n_ptr->addr = addr;
104 		spin_lock_init(&n_ptr->lock);
105 	INIT_LIST_HEAD(&n_ptr->nsub);
106 	n_ptr->owner = c_ptr;
107 	tipc_cltr_attach_node(c_ptr, n_ptr);
108 	n_ptr->last_router = -1;
109 
110 	/* Insert node into ordered list */
111 	for (curr_node = &tipc_nodes; *curr_node;
112 	     curr_node = &(*curr_node)->next) {
113 		if (addr < (*curr_node)->addr) {
114 			n_ptr->next = *curr_node;
115 			break;
116 		}
117 	}
118 	(*curr_node) = n_ptr;
119 	spin_unlock_bh(&node_create_lock);
120 	return n_ptr;
121 }
122 
123 void tipc_node_delete(struct tipc_node *n_ptr)
124 {
125 	if (!n_ptr)
126 		return;
127 
128 #if 0
129 	/* Not needed because links are already deleted via tipc_bearer_stop() */
130 
131 	u32 l_num;
132 
133 	for (l_num = 0; l_num < MAX_BEARERS; l_num++) {
134 		link_delete(n_ptr->links[l_num]);
135 	}
136 #endif
137 
138 	dbg("node %x deleted\n", n_ptr->addr);
139 	kfree(n_ptr);
140 }
141 
142 
143 /**
144  * tipc_node_link_up - handle addition of link
145  *
146  * Link becomes active (alone or shared) or standby, depending on its priority.
147  */
148 
149 void tipc_node_link_up(struct tipc_node *n_ptr, struct link *l_ptr)
150 {
151 	struct link **active = &n_ptr->active_links[0];
152 
153 	n_ptr->working_links++;
154 
155 	info("Established link <%s> on network plane %c\n",
156 	     l_ptr->name, l_ptr->b_ptr->net_plane);
157 
158 	if (!active[0]) {
159 		dbg(" link %x into %x/%x\n", l_ptr, &active[0], &active[1]);
160 		active[0] = active[1] = l_ptr;
161 		node_established_contact(n_ptr);
162 		return;
163 	}
164 	if (l_ptr->priority < active[0]->priority) {
165 		info("New link <%s> becomes standby\n", l_ptr->name);
166 		return;
167 	}
168 	tipc_link_send_duplicate(active[0], l_ptr);
169 	if (l_ptr->priority == active[0]->priority) {
170 		active[0] = l_ptr;
171 		return;
172 	}
173 	info("Old link <%s> becomes standby\n", active[0]->name);
174 	if (active[1] != active[0])
175 		info("Old link <%s> becomes standby\n", active[1]->name);
176 	active[0] = active[1] = l_ptr;
177 }
178 
179 /**
180  * node_select_active_links - select active link
181  */
182 
183 static void node_select_active_links(struct tipc_node *n_ptr)
184 {
185 	struct link **active = &n_ptr->active_links[0];
186 	u32 i;
187 	u32 highest_prio = 0;
188 
189 	active[0] = active[1] = NULL;
190 
191 	for (i = 0; i < MAX_BEARERS; i++) {
192 		struct link *l_ptr = n_ptr->links[i];
193 
194 		if (!l_ptr || !tipc_link_is_up(l_ptr) ||
195 		    (l_ptr->priority < highest_prio))
196 			continue;
197 
198 		if (l_ptr->priority > highest_prio) {
199 			highest_prio = l_ptr->priority;
200 			active[0] = active[1] = l_ptr;
201 		} else {
202 			active[1] = l_ptr;
203 		}
204 	}
205 }
206 
207 /**
208  * tipc_node_link_down - handle loss of link
209  */
210 
211 void tipc_node_link_down(struct tipc_node *n_ptr, struct link *l_ptr)
212 {
213 	struct link **active;
214 
215 	n_ptr->working_links--;
216 
217 	if (!tipc_link_is_active(l_ptr)) {
218 		info("Lost standby link <%s> on network plane %c\n",
219 		     l_ptr->name, l_ptr->b_ptr->net_plane);
220 		return;
221 	}
222 	info("Lost link <%s> on network plane %c\n",
223 		l_ptr->name, l_ptr->b_ptr->net_plane);
224 
225 	active = &n_ptr->active_links[0];
226 	if (active[0] == l_ptr)
227 		active[0] = active[1];
228 	if (active[1] == l_ptr)
229 		active[1] = active[0];
230 	if (active[0] == l_ptr)
231 		node_select_active_links(n_ptr);
232 	if (tipc_node_is_up(n_ptr))
233 		tipc_link_changeover(l_ptr);
234 	else
235 		node_lost_contact(n_ptr);
236 }
237 
238 int tipc_node_has_active_links(struct tipc_node *n_ptr)
239 {
240 	return (n_ptr &&
241 		((n_ptr->active_links[0]) || (n_ptr->active_links[1])));
242 }
243 
244 int tipc_node_has_redundant_links(struct tipc_node *n_ptr)
245 {
246 	return (n_ptr->working_links > 1);
247 }
248 
249 static int tipc_node_has_active_routes(struct tipc_node *n_ptr)
250 {
251 	return (n_ptr && (n_ptr->last_router >= 0));
252 }
253 
254 int tipc_node_is_up(struct tipc_node *n_ptr)
255 {
256 	return (tipc_node_has_active_links(n_ptr) || tipc_node_has_active_routes(n_ptr));
257 }
258 
259 struct tipc_node *tipc_node_attach_link(struct link *l_ptr)
260 {
261 	struct tipc_node *n_ptr = tipc_node_find(l_ptr->addr);
262 
263 	if (!n_ptr)
264 		n_ptr = tipc_node_create(l_ptr->addr);
265 	if (n_ptr) {
266 		u32 bearer_id = l_ptr->b_ptr->identity;
267 		char addr_string[16];
268 
269 		if (n_ptr->link_cnt >= 2) {
270 			err("Attempt to create third link to %s\n",
271 			    addr_string_fill(addr_string, n_ptr->addr));
272 			return NULL;
273 		}
274 
275 		if (!n_ptr->links[bearer_id]) {
276 			n_ptr->links[bearer_id] = l_ptr;
277 			tipc_net.zones[tipc_zone(l_ptr->addr)]->links++;
278 			n_ptr->link_cnt++;
279 			return n_ptr;
280 		}
281 		err("Attempt to establish second link on <%s> to %s \n",
282 		    l_ptr->b_ptr->publ.name,
283 		    addr_string_fill(addr_string, l_ptr->addr));
284 	}
285 	return NULL;
286 }
287 
288 void tipc_node_detach_link(struct tipc_node *n_ptr, struct link *l_ptr)
289 {
290 	n_ptr->links[l_ptr->b_ptr->identity] = NULL;
291 	tipc_net.zones[tipc_zone(l_ptr->addr)]->links--;
292 	n_ptr->link_cnt--;
293 }
294 
295 /*
296  * Routing table management - five cases to handle:
297  *
298  * 1: A link towards a zone/cluster external node comes up.
299  *    => Send a multicast message updating routing tables of all
300  *    system nodes within own cluster that the new destination
301  *    can be reached via this node.
302  *    (node.establishedContact()=>cluster.multicastNewRoute())
303  *
304  * 2: A link towards a slave node comes up.
305  *    => Send a multicast message updating routing tables of all
306  *    system nodes within own cluster that the new destination
307  *    can be reached via this node.
308  *    (node.establishedContact()=>cluster.multicastNewRoute())
309  *    => Send a  message to the slave node about existence
310  *    of all system nodes within cluster:
311  *    (node.establishedContact()=>cluster.sendLocalRoutes())
312  *
313  * 3: A new cluster local system node becomes available.
314  *    => Send message(s) to this particular node containing
315  *    information about all cluster external and slave
316  *     nodes which can be reached via this node.
317  *    (node.establishedContact()==>network.sendExternalRoutes())
318  *    (node.establishedContact()==>network.sendSlaveRoutes())
319  *    => Send messages to all directly connected slave nodes
320  *    containing information about the existence of the new node
321  *    (node.establishedContact()=>cluster.multicastNewRoute())
322  *
323  * 4: The link towards a zone/cluster external node or slave
324  *    node goes down.
325  *    => Send a multcast message updating routing tables of all
326  *    nodes within cluster that the new destination can not any
327  *    longer be reached via this node.
328  *    (node.lostAllLinks()=>cluster.bcastLostRoute())
329  *
330  * 5: A cluster local system node becomes unavailable.
331  *    => Remove all references to this node from the local
332  *    routing tables. Note: This is a completely node
333  *    local operation.
334  *    (node.lostAllLinks()=>network.removeAsRouter())
335  *    => Send messages to all directly connected slave nodes
336  *    containing information about loss of the node
337  *    (node.establishedContact()=>cluster.multicastLostRoute())
338  *
339  */
340 
341 static void node_established_contact(struct tipc_node *n_ptr)
342 {
343 	struct cluster *c_ptr;
344 
345 	dbg("node_established_contact:-> %x\n", n_ptr->addr);
346 	if (!tipc_node_has_active_routes(n_ptr) && in_own_cluster(n_ptr->addr)) {
347 		tipc_k_signal((Handler)tipc_named_node_up, n_ptr->addr);
348 	}
349 
350 	/* Syncronize broadcast acks */
351 	n_ptr->bclink.acked = tipc_bclink_get_last_sent();
352 
353 	if (is_slave(tipc_own_addr))
354 		return;
355 	if (!in_own_cluster(n_ptr->addr)) {
356 		/* Usage case 1 (see above) */
357 		c_ptr = tipc_cltr_find(tipc_own_addr);
358 		if (!c_ptr)
359 			c_ptr = tipc_cltr_create(tipc_own_addr);
360 		if (c_ptr)
361 			tipc_cltr_bcast_new_route(c_ptr, n_ptr->addr, 1,
362 						  tipc_max_nodes);
363 		return;
364 	}
365 
366 	c_ptr = n_ptr->owner;
367 	if (is_slave(n_ptr->addr)) {
368 		/* Usage case 2 (see above) */
369 		tipc_cltr_bcast_new_route(c_ptr, n_ptr->addr, 1, tipc_max_nodes);
370 		tipc_cltr_send_local_routes(c_ptr, n_ptr->addr);
371 		return;
372 	}
373 
374 	if (n_ptr->bclink.supported) {
375 		tipc_nmap_add(&tipc_cltr_bcast_nodes, n_ptr->addr);
376 		if (n_ptr->addr < tipc_own_addr)
377 			tipc_own_tag++;
378 	}
379 
380 	/* Case 3 (see above) */
381 	tipc_net_send_external_routes(n_ptr->addr);
382 	tipc_cltr_send_slave_routes(c_ptr, n_ptr->addr);
383 	tipc_cltr_bcast_new_route(c_ptr, n_ptr->addr, LOWEST_SLAVE,
384 				  tipc_highest_allowed_slave);
385 }
386 
387 static void node_lost_contact(struct tipc_node *n_ptr)
388 {
389 	struct cluster *c_ptr;
390 	struct tipc_node_subscr *ns, *tns;
391 	char addr_string[16];
392 	u32 i;
393 
394 	/* Clean up broadcast reception remains */
395 	n_ptr->bclink.gap_after = n_ptr->bclink.gap_to = 0;
396 	while (n_ptr->bclink.deferred_head) {
397 		struct sk_buff* buf = n_ptr->bclink.deferred_head;
398 		n_ptr->bclink.deferred_head = buf->next;
399 		buf_discard(buf);
400 	}
401 	if (n_ptr->bclink.defragm) {
402 		buf_discard(n_ptr->bclink.defragm);
403 		n_ptr->bclink.defragm = NULL;
404 	}
405 	if (in_own_cluster(n_ptr->addr) && n_ptr->bclink.supported) {
406 		tipc_bclink_acknowledge(n_ptr, mod(n_ptr->bclink.acked + 10000));
407 	}
408 
409 	/* Update routing tables */
410 	if (is_slave(tipc_own_addr)) {
411 		tipc_net_remove_as_router(n_ptr->addr);
412 	} else {
413 		if (!in_own_cluster(n_ptr->addr)) {
414 			/* Case 4 (see above) */
415 			c_ptr = tipc_cltr_find(tipc_own_addr);
416 			tipc_cltr_bcast_lost_route(c_ptr, n_ptr->addr, 1,
417 						   tipc_max_nodes);
418 		} else {
419 			/* Case 5 (see above) */
420 			c_ptr = tipc_cltr_find(n_ptr->addr);
421 			if (is_slave(n_ptr->addr)) {
422 				tipc_cltr_bcast_lost_route(c_ptr, n_ptr->addr, 1,
423 							   tipc_max_nodes);
424 			} else {
425 				if (n_ptr->bclink.supported) {
426 					tipc_nmap_remove(&tipc_cltr_bcast_nodes,
427 							 n_ptr->addr);
428 					if (n_ptr->addr < tipc_own_addr)
429 						tipc_own_tag--;
430 				}
431 				tipc_net_remove_as_router(n_ptr->addr);
432 				tipc_cltr_bcast_lost_route(c_ptr, n_ptr->addr,
433 							   LOWEST_SLAVE,
434 							   tipc_highest_allowed_slave);
435 			}
436 		}
437 	}
438 	if (tipc_node_has_active_routes(n_ptr))
439 		return;
440 
441 	info("Lost contact with %s\n",
442 	     addr_string_fill(addr_string, n_ptr->addr));
443 
444 	/* Abort link changeover */
445 	for (i = 0; i < MAX_BEARERS; i++) {
446 		struct link *l_ptr = n_ptr->links[i];
447 		if (!l_ptr)
448 			continue;
449 		l_ptr->reset_checkpoint = l_ptr->next_in_no;
450 		l_ptr->exp_msg_count = 0;
451 		tipc_link_reset_fragments(l_ptr);
452 	}
453 
454 	/* Notify subscribers */
455 	list_for_each_entry_safe(ns, tns, &n_ptr->nsub, nodesub_list) {
456 		ns->node = NULL;
457 		list_del_init(&ns->nodesub_list);
458 		tipc_k_signal((Handler)ns->handle_node_down,
459 			      (unsigned long)ns->usr_handle);
460 	}
461 }
462 
463 /**
464  * tipc_node_select_next_hop - find the next-hop node for a message
465  *
466  * Called by when cluster local lookup has failed.
467  */
468 
469 struct tipc_node *tipc_node_select_next_hop(u32 addr, u32 selector)
470 {
471 	struct tipc_node *n_ptr;
472 	u32 router_addr;
473 
474 	if (!tipc_addr_domain_valid(addr))
475 		return NULL;
476 
477 	/* Look for direct link to destination processsor */
478 	n_ptr = tipc_node_find(addr);
479 	if (n_ptr && tipc_node_has_active_links(n_ptr))
480 		return n_ptr;
481 
482 	/* Cluster local system nodes *must* have direct links */
483 	if (!is_slave(addr) && in_own_cluster(addr))
484 		return NULL;
485 
486 	/* Look for cluster local router with direct link to node */
487 	router_addr = tipc_node_select_router(n_ptr, selector);
488 	if (router_addr)
489 		return tipc_node_select(router_addr, selector);
490 
491 	/* Slave nodes can only be accessed within own cluster via a
492 	   known router with direct link -- if no router was found,give up */
493 	if (is_slave(addr))
494 		return NULL;
495 
496 	/* Inter zone/cluster -- find any direct link to remote cluster */
497 	addr = tipc_addr(tipc_zone(addr), tipc_cluster(addr), 0);
498 	n_ptr = tipc_net_select_remote_node(addr, selector);
499 	if (n_ptr && tipc_node_has_active_links(n_ptr))
500 		return n_ptr;
501 
502 	/* Last resort -- look for any router to anywhere in remote zone */
503 	router_addr =  tipc_net_select_router(addr, selector);
504 	if (router_addr)
505 		return tipc_node_select(router_addr, selector);
506 
507 	return NULL;
508 }
509 
510 /**
511  * tipc_node_select_router - select router to reach specified node
512  *
513  * Uses a deterministic and fair algorithm for selecting router node.
514  */
515 
516 u32 tipc_node_select_router(struct tipc_node *n_ptr, u32 ref)
517 {
518 	u32 ulim;
519 	u32 mask;
520 	u32 start;
521 	u32 r;
522 
523 	if (!n_ptr)
524 		return 0;
525 
526 	if (n_ptr->last_router < 0)
527 		return 0;
528 	ulim = ((n_ptr->last_router + 1) * 32) - 1;
529 
530 	/* Start entry must be random */
531 	mask = tipc_max_nodes;
532 	while (mask > ulim)
533 		mask >>= 1;
534 	start = ref & mask;
535 	r = start;
536 
537 	/* Lookup upwards with wrap-around */
538 	do {
539 		if (((n_ptr->routers[r / 32]) >> (r % 32)) & 1)
540 			break;
541 	} while (++r <= ulim);
542 	if (r > ulim) {
543 		r = 1;
544 		do {
545 			if (((n_ptr->routers[r / 32]) >> (r % 32)) & 1)
546 				break;
547 		} while (++r < start);
548 		assert(r != start);
549 	}
550 	assert(r && (r <= ulim));
551 	return tipc_addr(own_zone(), own_cluster(), r);
552 }
553 
554 void tipc_node_add_router(struct tipc_node *n_ptr, u32 router)
555 {
556 	u32 r_num = tipc_node(router);
557 
558 	n_ptr->routers[r_num / 32] =
559 		((1 << (r_num % 32)) | n_ptr->routers[r_num / 32]);
560 	n_ptr->last_router = tipc_max_nodes / 32;
561 	while ((--n_ptr->last_router >= 0) &&
562 	       !n_ptr->routers[n_ptr->last_router]);
563 }
564 
565 void tipc_node_remove_router(struct tipc_node *n_ptr, u32 router)
566 {
567 	u32 r_num = tipc_node(router);
568 
569 	if (n_ptr->last_router < 0)
570 		return;		/* No routes */
571 
572 	n_ptr->routers[r_num / 32] =
573 		((~(1 << (r_num % 32))) & (n_ptr->routers[r_num / 32]));
574 	n_ptr->last_router = tipc_max_nodes / 32;
575 	while ((--n_ptr->last_router >= 0) &&
576 	       !n_ptr->routers[n_ptr->last_router]);
577 
578 	if (!tipc_node_is_up(n_ptr))
579 		node_lost_contact(n_ptr);
580 }
581 
582 #if 0
583 void node_print(struct print_buf *buf, struct tipc_node *n_ptr, char *str)
584 {
585 	u32 i;
586 
587 	tipc_printf(buf, "\n\n%s", str);
588 	for (i = 0; i < MAX_BEARERS; i++) {
589 		if (!n_ptr->links[i])
590 			continue;
591 		tipc_printf(buf, "Links[%u]: %x, ", i, n_ptr->links[i]);
592 	}
593 	tipc_printf(buf, "Active links: [%x,%x]\n",
594 		    n_ptr->active_links[0], n_ptr->active_links[1]);
595 }
596 #endif
597 
598 u32 tipc_available_nodes(const u32 domain)
599 {
600 	struct tipc_node *n_ptr;
601 	u32 cnt = 0;
602 
603 	read_lock_bh(&tipc_net_lock);
604 	for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
605 		if (!in_scope(domain, n_ptr->addr))
606 			continue;
607 		if (tipc_node_is_up(n_ptr))
608 			cnt++;
609 	}
610 	read_unlock_bh(&tipc_net_lock);
611 	return cnt;
612 }
613 
614 struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space)
615 {
616 	u32 domain;
617 	struct sk_buff *buf;
618 	struct tipc_node *n_ptr;
619 	struct tipc_node_info node_info;
620 	u32 payload_size;
621 
622 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
623 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
624 
625 	domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
626 	if (!tipc_addr_domain_valid(domain))
627 		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
628 						   " (network address)");
629 
630 	read_lock_bh(&tipc_net_lock);
631 	if (!tipc_nodes) {
632 		read_unlock_bh(&tipc_net_lock);
633 		return tipc_cfg_reply_none();
634 	}
635 
636 	/* For now, get space for all other nodes
637 	   (will need to modify this when slave nodes are supported */
638 
639 	payload_size = TLV_SPACE(sizeof(node_info)) * (tipc_max_nodes - 1);
640 	if (payload_size > 32768u) {
641 		read_unlock_bh(&tipc_net_lock);
642 		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
643 						   " (too many nodes)");
644 	}
645 	buf = tipc_cfg_reply_alloc(payload_size);
646 	if (!buf) {
647 		read_unlock_bh(&tipc_net_lock);
648 		return NULL;
649 	}
650 
651 	/* Add TLVs for all nodes in scope */
652 
653 	for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
654 		if (!in_scope(domain, n_ptr->addr))
655 			continue;
656 		node_info.addr = htonl(n_ptr->addr);
657 		node_info.up = htonl(tipc_node_is_up(n_ptr));
658 		tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
659 				    &node_info, sizeof(node_info));
660 	}
661 
662 	read_unlock_bh(&tipc_net_lock);
663 	return buf;
664 }
665 
666 struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
667 {
668 	u32 domain;
669 	struct sk_buff *buf;
670 	struct tipc_node *n_ptr;
671 	struct tipc_link_info link_info;
672 	u32 payload_size;
673 
674 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
675 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
676 
677 	domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
678 	if (!tipc_addr_domain_valid(domain))
679 		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
680 						   " (network address)");
681 
682 	if (tipc_mode != TIPC_NET_MODE)
683 		return tipc_cfg_reply_none();
684 
685 	read_lock_bh(&tipc_net_lock);
686 
687 	/* Get space for all unicast links + multicast link */
688 
689 	payload_size = TLV_SPACE(sizeof(link_info)) *
690 		(tipc_net.zones[tipc_zone(tipc_own_addr)]->links + 1);
691 	if (payload_size > 32768u) {
692 		read_unlock_bh(&tipc_net_lock);
693 		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
694 						   " (too many links)");
695 	}
696 	buf = tipc_cfg_reply_alloc(payload_size);
697 	if (!buf) {
698 		read_unlock_bh(&tipc_net_lock);
699 		return NULL;
700 	}
701 
702 	/* Add TLV for broadcast link */
703 
704 	link_info.dest = htonl(tipc_own_addr & 0xfffff00);
705 	link_info.up = htonl(1);
706 	strlcpy(link_info.str, tipc_bclink_name, TIPC_MAX_LINK_NAME);
707 	tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));
708 
709 	/* Add TLVs for any other links in scope */
710 
711 	for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
712 		u32 i;
713 
714 		if (!in_scope(domain, n_ptr->addr))
715 			continue;
716 		tipc_node_lock(n_ptr);
717 		for (i = 0; i < MAX_BEARERS; i++) {
718 			if (!n_ptr->links[i])
719 				continue;
720 			link_info.dest = htonl(n_ptr->addr);
721 			link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
722 			strcpy(link_info.str, n_ptr->links[i]->name);
723 			tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
724 					    &link_info, sizeof(link_info));
725 		}
726 		tipc_node_unlock(n_ptr);
727 	}
728 
729 	read_unlock_bh(&tipc_net_lock);
730 	return buf;
731 }
732