xref: /linux/net/tipc/node.c (revision 036b9e7caeb09598afb297a6d4fb36b477a4f6b2)
1 /*
2  * net/tipc/node.c: TIPC node management routines
3  *
4  * Copyright (c) 2000-2006, 2012-2016, Ericsson AB
5  * Copyright (c) 2005-2006, 2010-2014, 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 "link.h"
39 #include "node.h"
40 #include "name_distr.h"
41 #include "socket.h"
42 #include "bcast.h"
43 #include "monitor.h"
44 #include "discover.h"
45 #include "netlink.h"
46 
47 #define INVALID_NODE_SIG	0x10000
48 #define NODE_CLEANUP_AFTER	300000
49 
50 /* Flags used to take different actions according to flag type
51  * TIPC_NOTIFY_NODE_DOWN: notify node is down
52  * TIPC_NOTIFY_NODE_UP: notify node is up
53  * TIPC_DISTRIBUTE_NAME: publish or withdraw link state name type
54  */
55 enum {
56 	TIPC_NOTIFY_NODE_DOWN		= (1 << 3),
57 	TIPC_NOTIFY_NODE_UP		= (1 << 4),
58 	TIPC_NOTIFY_LINK_UP		= (1 << 6),
59 	TIPC_NOTIFY_LINK_DOWN		= (1 << 7)
60 };
61 
62 struct tipc_link_entry {
63 	struct tipc_link *link;
64 	spinlock_t lock; /* per link */
65 	u32 mtu;
66 	struct sk_buff_head inputq;
67 	struct tipc_media_addr maddr;
68 };
69 
70 struct tipc_bclink_entry {
71 	struct tipc_link *link;
72 	struct sk_buff_head inputq1;
73 	struct sk_buff_head arrvq;
74 	struct sk_buff_head inputq2;
75 	struct sk_buff_head namedq;
76 };
77 
78 /**
79  * struct tipc_node - TIPC node structure
80  * @addr: network address of node
81  * @ref: reference counter to node object
82  * @lock: rwlock governing access to structure
83  * @net: the applicable net namespace
84  * @hash: links to adjacent nodes in unsorted hash chain
85  * @inputq: pointer to input queue containing messages for msg event
86  * @namedq: pointer to name table input queue with name table messages
87  * @active_links: bearer ids of active links, used as index into links[] array
88  * @links: array containing references to all links to node
89  * @action_flags: bit mask of different types of node actions
90  * @state: connectivity state vs peer node
91  * @sync_point: sequence number where synch/failover is finished
92  * @list: links to adjacent nodes in sorted list of cluster's nodes
93  * @working_links: number of working links to node (both active and standby)
94  * @link_cnt: number of links to node
95  * @capabilities: bitmap, indicating peer node's functional capabilities
96  * @signature: node instance identifier
97  * @link_id: local and remote bearer ids of changing link, if any
98  * @publ_list: list of publications
99  * @rcu: rcu struct for tipc_node
100  * @delete_at: indicates the time for deleting a down node
101  */
102 struct tipc_node {
103 	u32 addr;
104 	struct kref kref;
105 	rwlock_t lock;
106 	struct net *net;
107 	struct hlist_node hash;
108 	int active_links[2];
109 	struct tipc_link_entry links[MAX_BEARERS];
110 	struct tipc_bclink_entry bc_entry;
111 	int action_flags;
112 	struct list_head list;
113 	int state;
114 	bool failover_sent;
115 	u16 sync_point;
116 	int link_cnt;
117 	u16 working_links;
118 	u16 capabilities;
119 	u32 signature;
120 	u32 link_id;
121 	u8 peer_id[16];
122 	struct list_head publ_list;
123 	struct list_head conn_sks;
124 	unsigned long keepalive_intv;
125 	struct timer_list timer;
126 	struct rcu_head rcu;
127 	unsigned long delete_at;
128 };
129 
130 /* Node FSM states and events:
131  */
132 enum {
133 	SELF_DOWN_PEER_DOWN    = 0xdd,
134 	SELF_UP_PEER_UP        = 0xaa,
135 	SELF_DOWN_PEER_LEAVING = 0xd1,
136 	SELF_UP_PEER_COMING    = 0xac,
137 	SELF_COMING_PEER_UP    = 0xca,
138 	SELF_LEAVING_PEER_DOWN = 0x1d,
139 	NODE_FAILINGOVER       = 0xf0,
140 	NODE_SYNCHING          = 0xcc
141 };
142 
143 enum {
144 	SELF_ESTABL_CONTACT_EVT = 0xece,
145 	SELF_LOST_CONTACT_EVT   = 0x1ce,
146 	PEER_ESTABL_CONTACT_EVT = 0x9ece,
147 	PEER_LOST_CONTACT_EVT   = 0x91ce,
148 	NODE_FAILOVER_BEGIN_EVT = 0xfbe,
149 	NODE_FAILOVER_END_EVT   = 0xfee,
150 	NODE_SYNCH_BEGIN_EVT    = 0xcbe,
151 	NODE_SYNCH_END_EVT      = 0xcee
152 };
153 
154 static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
155 				  struct sk_buff_head *xmitq,
156 				  struct tipc_media_addr **maddr);
157 static void tipc_node_link_down(struct tipc_node *n, int bearer_id,
158 				bool delete);
159 static void node_lost_contact(struct tipc_node *n, struct sk_buff_head *inputq);
160 static void tipc_node_delete(struct tipc_node *node);
161 static void tipc_node_timeout(struct timer_list *t);
162 static void tipc_node_fsm_evt(struct tipc_node *n, int evt);
163 static struct tipc_node *tipc_node_find(struct net *net, u32 addr);
164 static struct tipc_node *tipc_node_find_by_id(struct net *net, u8 *id);
165 static void tipc_node_put(struct tipc_node *node);
166 static bool node_is_up(struct tipc_node *n);
167 static void tipc_node_delete_from_list(struct tipc_node *node);
168 
169 struct tipc_sock_conn {
170 	u32 port;
171 	u32 peer_port;
172 	u32 peer_node;
173 	struct list_head list;
174 };
175 
176 static struct tipc_link *node_active_link(struct tipc_node *n, int sel)
177 {
178 	int bearer_id = n->active_links[sel & 1];
179 
180 	if (unlikely(bearer_id == INVALID_BEARER_ID))
181 		return NULL;
182 
183 	return n->links[bearer_id].link;
184 }
185 
186 int tipc_node_get_mtu(struct net *net, u32 addr, u32 sel)
187 {
188 	struct tipc_node *n;
189 	int bearer_id;
190 	unsigned int mtu = MAX_MSG_SIZE;
191 
192 	n = tipc_node_find(net, addr);
193 	if (unlikely(!n))
194 		return mtu;
195 
196 	bearer_id = n->active_links[sel & 1];
197 	if (likely(bearer_id != INVALID_BEARER_ID))
198 		mtu = n->links[bearer_id].mtu;
199 	tipc_node_put(n);
200 	return mtu;
201 }
202 
203 bool tipc_node_get_id(struct net *net, u32 addr, u8 *id)
204 {
205 	u8 *own_id = tipc_own_id(net);
206 	struct tipc_node *n;
207 
208 	if (!own_id)
209 		return true;
210 
211 	if (addr == tipc_own_addr(net)) {
212 		memcpy(id, own_id, TIPC_NODEID_LEN);
213 		return true;
214 	}
215 	n = tipc_node_find(net, addr);
216 	if (!n)
217 		return false;
218 
219 	memcpy(id, &n->peer_id, TIPC_NODEID_LEN);
220 	tipc_node_put(n);
221 	return true;
222 }
223 
224 u16 tipc_node_get_capabilities(struct net *net, u32 addr)
225 {
226 	struct tipc_node *n;
227 	u16 caps;
228 
229 	n = tipc_node_find(net, addr);
230 	if (unlikely(!n))
231 		return TIPC_NODE_CAPABILITIES;
232 	caps = n->capabilities;
233 	tipc_node_put(n);
234 	return caps;
235 }
236 
237 static void tipc_node_kref_release(struct kref *kref)
238 {
239 	struct tipc_node *n = container_of(kref, struct tipc_node, kref);
240 
241 	kfree(n->bc_entry.link);
242 	kfree_rcu(n, rcu);
243 }
244 
245 static void tipc_node_put(struct tipc_node *node)
246 {
247 	kref_put(&node->kref, tipc_node_kref_release);
248 }
249 
250 static void tipc_node_get(struct tipc_node *node)
251 {
252 	kref_get(&node->kref);
253 }
254 
255 /*
256  * tipc_node_find - locate specified node object, if it exists
257  */
258 static struct tipc_node *tipc_node_find(struct net *net, u32 addr)
259 {
260 	struct tipc_net *tn = tipc_net(net);
261 	struct tipc_node *node;
262 	unsigned int thash = tipc_hashfn(addr);
263 
264 	rcu_read_lock();
265 	hlist_for_each_entry_rcu(node, &tn->node_htable[thash], hash) {
266 		if (node->addr != addr)
267 			continue;
268 		if (!kref_get_unless_zero(&node->kref))
269 			node = NULL;
270 		break;
271 	}
272 	rcu_read_unlock();
273 	return node;
274 }
275 
276 /* tipc_node_find_by_id - locate specified node object by its 128-bit id
277  * Note: this function is called only when a discovery request failed
278  * to find the node by its 32-bit id, and is not time critical
279  */
280 static struct tipc_node *tipc_node_find_by_id(struct net *net, u8 *id)
281 {
282 	struct tipc_net *tn = tipc_net(net);
283 	struct tipc_node *n;
284 	bool found = false;
285 
286 	rcu_read_lock();
287 	list_for_each_entry_rcu(n, &tn->node_list, list) {
288 		read_lock_bh(&n->lock);
289 		if (!memcmp(id, n->peer_id, 16) &&
290 		    kref_get_unless_zero(&n->kref))
291 			found = true;
292 		read_unlock_bh(&n->lock);
293 		if (found)
294 			break;
295 	}
296 	rcu_read_unlock();
297 	return found ? n : NULL;
298 }
299 
300 static void tipc_node_read_lock(struct tipc_node *n)
301 {
302 	read_lock_bh(&n->lock);
303 }
304 
305 static void tipc_node_read_unlock(struct tipc_node *n)
306 {
307 	read_unlock_bh(&n->lock);
308 }
309 
310 static void tipc_node_write_lock(struct tipc_node *n)
311 {
312 	write_lock_bh(&n->lock);
313 }
314 
315 static void tipc_node_write_unlock_fast(struct tipc_node *n)
316 {
317 	write_unlock_bh(&n->lock);
318 }
319 
320 static void tipc_node_write_unlock(struct tipc_node *n)
321 {
322 	struct net *net = n->net;
323 	u32 addr = 0;
324 	u32 flags = n->action_flags;
325 	u32 link_id = 0;
326 	u32 bearer_id;
327 	struct list_head *publ_list;
328 
329 	if (likely(!flags)) {
330 		write_unlock_bh(&n->lock);
331 		return;
332 	}
333 
334 	addr = n->addr;
335 	link_id = n->link_id;
336 	bearer_id = link_id & 0xffff;
337 	publ_list = &n->publ_list;
338 
339 	n->action_flags &= ~(TIPC_NOTIFY_NODE_DOWN | TIPC_NOTIFY_NODE_UP |
340 			     TIPC_NOTIFY_LINK_DOWN | TIPC_NOTIFY_LINK_UP);
341 
342 	write_unlock_bh(&n->lock);
343 
344 	if (flags & TIPC_NOTIFY_NODE_DOWN)
345 		tipc_publ_notify(net, publ_list, addr);
346 
347 	if (flags & TIPC_NOTIFY_NODE_UP)
348 		tipc_named_node_up(net, addr);
349 
350 	if (flags & TIPC_NOTIFY_LINK_UP) {
351 		tipc_mon_peer_up(net, addr, bearer_id);
352 		tipc_nametbl_publish(net, TIPC_LINK_STATE, addr, addr,
353 				     TIPC_NODE_SCOPE, link_id, link_id);
354 	}
355 	if (flags & TIPC_NOTIFY_LINK_DOWN) {
356 		tipc_mon_peer_down(net, addr, bearer_id);
357 		tipc_nametbl_withdraw(net, TIPC_LINK_STATE, addr,
358 				      addr, link_id);
359 	}
360 }
361 
362 static struct tipc_node *tipc_node_create(struct net *net, u32 addr,
363 					  u8 *peer_id, u16 capabilities)
364 {
365 	struct tipc_net *tn = net_generic(net, tipc_net_id);
366 	struct tipc_node *n, *temp_node;
367 	struct tipc_link *l;
368 	int bearer_id;
369 	int i;
370 
371 	spin_lock_bh(&tn->node_list_lock);
372 	n = tipc_node_find(net, addr);
373 	if (n) {
374 		if (n->capabilities == capabilities)
375 			goto exit;
376 		/* Same node may come back with new capabilities */
377 		write_lock_bh(&n->lock);
378 		n->capabilities = capabilities;
379 		for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
380 			l = n->links[bearer_id].link;
381 			if (l)
382 				tipc_link_update_caps(l, capabilities);
383 		}
384 		write_unlock_bh(&n->lock);
385 		goto exit;
386 	}
387 	n = kzalloc(sizeof(*n), GFP_ATOMIC);
388 	if (!n) {
389 		pr_warn("Node creation failed, no memory\n");
390 		goto exit;
391 	}
392 	n->addr = addr;
393 	memcpy(&n->peer_id, peer_id, 16);
394 	n->net = net;
395 	n->capabilities = capabilities;
396 	kref_init(&n->kref);
397 	rwlock_init(&n->lock);
398 	INIT_HLIST_NODE(&n->hash);
399 	INIT_LIST_HEAD(&n->list);
400 	INIT_LIST_HEAD(&n->publ_list);
401 	INIT_LIST_HEAD(&n->conn_sks);
402 	skb_queue_head_init(&n->bc_entry.namedq);
403 	skb_queue_head_init(&n->bc_entry.inputq1);
404 	__skb_queue_head_init(&n->bc_entry.arrvq);
405 	skb_queue_head_init(&n->bc_entry.inputq2);
406 	for (i = 0; i < MAX_BEARERS; i++)
407 		spin_lock_init(&n->links[i].lock);
408 	n->state = SELF_DOWN_PEER_LEAVING;
409 	n->delete_at = jiffies + msecs_to_jiffies(NODE_CLEANUP_AFTER);
410 	n->signature = INVALID_NODE_SIG;
411 	n->active_links[0] = INVALID_BEARER_ID;
412 	n->active_links[1] = INVALID_BEARER_ID;
413 	if (!tipc_link_bc_create(net, tipc_own_addr(net),
414 				 addr, U16_MAX,
415 				 tipc_link_window(tipc_bc_sndlink(net)),
416 				 n->capabilities,
417 				 &n->bc_entry.inputq1,
418 				 &n->bc_entry.namedq,
419 				 tipc_bc_sndlink(net),
420 				 &n->bc_entry.link)) {
421 		pr_warn("Broadcast rcv link creation failed, no memory\n");
422 		kfree(n);
423 		n = NULL;
424 		goto exit;
425 	}
426 	tipc_node_get(n);
427 	timer_setup(&n->timer, tipc_node_timeout, 0);
428 	n->keepalive_intv = U32_MAX;
429 	hlist_add_head_rcu(&n->hash, &tn->node_htable[tipc_hashfn(addr)]);
430 	list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
431 		if (n->addr < temp_node->addr)
432 			break;
433 	}
434 	list_add_tail_rcu(&n->list, &temp_node->list);
435 exit:
436 	spin_unlock_bh(&tn->node_list_lock);
437 	return n;
438 }
439 
440 static void tipc_node_calculate_timer(struct tipc_node *n, struct tipc_link *l)
441 {
442 	unsigned long tol = tipc_link_tolerance(l);
443 	unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
444 
445 	/* Link with lowest tolerance determines timer interval */
446 	if (intv < n->keepalive_intv)
447 		n->keepalive_intv = intv;
448 
449 	/* Ensure link's abort limit corresponds to current tolerance */
450 	tipc_link_set_abort_limit(l, tol / n->keepalive_intv);
451 }
452 
453 static void tipc_node_delete_from_list(struct tipc_node *node)
454 {
455 	list_del_rcu(&node->list);
456 	hlist_del_rcu(&node->hash);
457 	tipc_node_put(node);
458 }
459 
460 static void tipc_node_delete(struct tipc_node *node)
461 {
462 	tipc_node_delete_from_list(node);
463 
464 	del_timer_sync(&node->timer);
465 	tipc_node_put(node);
466 }
467 
468 void tipc_node_stop(struct net *net)
469 {
470 	struct tipc_net *tn = tipc_net(net);
471 	struct tipc_node *node, *t_node;
472 
473 	spin_lock_bh(&tn->node_list_lock);
474 	list_for_each_entry_safe(node, t_node, &tn->node_list, list)
475 		tipc_node_delete(node);
476 	spin_unlock_bh(&tn->node_list_lock);
477 }
478 
479 void tipc_node_subscribe(struct net *net, struct list_head *subscr, u32 addr)
480 {
481 	struct tipc_node *n;
482 
483 	if (in_own_node(net, addr))
484 		return;
485 
486 	n = tipc_node_find(net, addr);
487 	if (!n) {
488 		pr_warn("Node subscribe rejected, unknown node 0x%x\n", addr);
489 		return;
490 	}
491 	tipc_node_write_lock(n);
492 	list_add_tail(subscr, &n->publ_list);
493 	tipc_node_write_unlock_fast(n);
494 	tipc_node_put(n);
495 }
496 
497 void tipc_node_unsubscribe(struct net *net, struct list_head *subscr, u32 addr)
498 {
499 	struct tipc_node *n;
500 
501 	if (in_own_node(net, addr))
502 		return;
503 
504 	n = tipc_node_find(net, addr);
505 	if (!n) {
506 		pr_warn("Node unsubscribe rejected, unknown node 0x%x\n", addr);
507 		return;
508 	}
509 	tipc_node_write_lock(n);
510 	list_del_init(subscr);
511 	tipc_node_write_unlock_fast(n);
512 	tipc_node_put(n);
513 }
514 
515 int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port)
516 {
517 	struct tipc_node *node;
518 	struct tipc_sock_conn *conn;
519 	int err = 0;
520 
521 	if (in_own_node(net, dnode))
522 		return 0;
523 
524 	node = tipc_node_find(net, dnode);
525 	if (!node) {
526 		pr_warn("Connecting sock to node 0x%x failed\n", dnode);
527 		return -EHOSTUNREACH;
528 	}
529 	conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
530 	if (!conn) {
531 		err = -EHOSTUNREACH;
532 		goto exit;
533 	}
534 	conn->peer_node = dnode;
535 	conn->port = port;
536 	conn->peer_port = peer_port;
537 
538 	tipc_node_write_lock(node);
539 	list_add_tail(&conn->list, &node->conn_sks);
540 	tipc_node_write_unlock(node);
541 exit:
542 	tipc_node_put(node);
543 	return err;
544 }
545 
546 void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port)
547 {
548 	struct tipc_node *node;
549 	struct tipc_sock_conn *conn, *safe;
550 
551 	if (in_own_node(net, dnode))
552 		return;
553 
554 	node = tipc_node_find(net, dnode);
555 	if (!node)
556 		return;
557 
558 	tipc_node_write_lock(node);
559 	list_for_each_entry_safe(conn, safe, &node->conn_sks, list) {
560 		if (port != conn->port)
561 			continue;
562 		list_del(&conn->list);
563 		kfree(conn);
564 	}
565 	tipc_node_write_unlock(node);
566 	tipc_node_put(node);
567 }
568 
569 static void  tipc_node_clear_links(struct tipc_node *node)
570 {
571 	int i;
572 
573 	for (i = 0; i < MAX_BEARERS; i++) {
574 		struct tipc_link_entry *le = &node->links[i];
575 
576 		if (le->link) {
577 			kfree(le->link);
578 			le->link = NULL;
579 			node->link_cnt--;
580 		}
581 	}
582 }
583 
584 /* tipc_node_cleanup - delete nodes that does not
585  * have active links for NODE_CLEANUP_AFTER time
586  */
587 static bool tipc_node_cleanup(struct tipc_node *peer)
588 {
589 	struct tipc_net *tn = tipc_net(peer->net);
590 	bool deleted = false;
591 
592 	/* If lock held by tipc_node_stop() the node will be deleted anyway */
593 	if (!spin_trylock_bh(&tn->node_list_lock))
594 		return false;
595 
596 	tipc_node_write_lock(peer);
597 
598 	if (!node_is_up(peer) && time_after(jiffies, peer->delete_at)) {
599 		tipc_node_clear_links(peer);
600 		tipc_node_delete_from_list(peer);
601 		deleted = true;
602 	}
603 	tipc_node_write_unlock(peer);
604 	spin_unlock_bh(&tn->node_list_lock);
605 	return deleted;
606 }
607 
608 /* tipc_node_timeout - handle expiration of node timer
609  */
610 static void tipc_node_timeout(struct timer_list *t)
611 {
612 	struct tipc_node *n = from_timer(n, t, timer);
613 	struct tipc_link_entry *le;
614 	struct sk_buff_head xmitq;
615 	int remains = n->link_cnt;
616 	int bearer_id;
617 	int rc = 0;
618 
619 	if (!node_is_up(n) && tipc_node_cleanup(n)) {
620 		/*Removing the reference of Timer*/
621 		tipc_node_put(n);
622 		return;
623 	}
624 
625 	__skb_queue_head_init(&xmitq);
626 
627 	/* Initial node interval to value larger (10 seconds), then it will be
628 	 * recalculated with link lowest tolerance
629 	 */
630 	tipc_node_read_lock(n);
631 	n->keepalive_intv = 10000;
632 	tipc_node_read_unlock(n);
633 	for (bearer_id = 0; remains && (bearer_id < MAX_BEARERS); bearer_id++) {
634 		tipc_node_read_lock(n);
635 		le = &n->links[bearer_id];
636 		if (le->link) {
637 			spin_lock_bh(&le->lock);
638 			/* Link tolerance may change asynchronously: */
639 			tipc_node_calculate_timer(n, le->link);
640 			rc = tipc_link_timeout(le->link, &xmitq);
641 			spin_unlock_bh(&le->lock);
642 			remains--;
643 		}
644 		tipc_node_read_unlock(n);
645 		tipc_bearer_xmit(n->net, bearer_id, &xmitq, &le->maddr);
646 		if (rc & TIPC_LINK_DOWN_EVT)
647 			tipc_node_link_down(n, bearer_id, false);
648 	}
649 	mod_timer(&n->timer, jiffies + msecs_to_jiffies(n->keepalive_intv));
650 }
651 
652 /**
653  * __tipc_node_link_up - handle addition of link
654  * Node lock must be held by caller
655  * Link becomes active (alone or shared) or standby, depending on its priority.
656  */
657 static void __tipc_node_link_up(struct tipc_node *n, int bearer_id,
658 				struct sk_buff_head *xmitq)
659 {
660 	int *slot0 = &n->active_links[0];
661 	int *slot1 = &n->active_links[1];
662 	struct tipc_link *ol = node_active_link(n, 0);
663 	struct tipc_link *nl = n->links[bearer_id].link;
664 
665 	if (!nl || tipc_link_is_up(nl))
666 		return;
667 
668 	tipc_link_fsm_evt(nl, LINK_ESTABLISH_EVT);
669 	if (!tipc_link_is_up(nl))
670 		return;
671 
672 	n->working_links++;
673 	n->action_flags |= TIPC_NOTIFY_LINK_UP;
674 	n->link_id = tipc_link_id(nl);
675 
676 	/* Leave room for tunnel header when returning 'mtu' to users: */
677 	n->links[bearer_id].mtu = tipc_link_mtu(nl) - INT_H_SIZE;
678 
679 	tipc_bearer_add_dest(n->net, bearer_id, n->addr);
680 	tipc_bcast_inc_bearer_dst_cnt(n->net, bearer_id);
681 
682 	pr_debug("Established link <%s> on network plane %c\n",
683 		 tipc_link_name(nl), tipc_link_plane(nl));
684 
685 	/* Ensure that a STATE message goes first */
686 	tipc_link_build_state_msg(nl, xmitq);
687 
688 	/* First link? => give it both slots */
689 	if (!ol) {
690 		*slot0 = bearer_id;
691 		*slot1 = bearer_id;
692 		tipc_node_fsm_evt(n, SELF_ESTABL_CONTACT_EVT);
693 		n->failover_sent = false;
694 		n->action_flags |= TIPC_NOTIFY_NODE_UP;
695 		tipc_link_set_active(nl, true);
696 		tipc_bcast_add_peer(n->net, nl, xmitq);
697 		return;
698 	}
699 
700 	/* Second link => redistribute slots */
701 	if (tipc_link_prio(nl) > tipc_link_prio(ol)) {
702 		pr_debug("Old link <%s> becomes standby\n", tipc_link_name(ol));
703 		*slot0 = bearer_id;
704 		*slot1 = bearer_id;
705 		tipc_link_set_active(nl, true);
706 		tipc_link_set_active(ol, false);
707 	} else if (tipc_link_prio(nl) == tipc_link_prio(ol)) {
708 		tipc_link_set_active(nl, true);
709 		*slot1 = bearer_id;
710 	} else {
711 		pr_debug("New link <%s> is standby\n", tipc_link_name(nl));
712 	}
713 
714 	/* Prepare synchronization with first link */
715 	tipc_link_tnl_prepare(ol, nl, SYNCH_MSG, xmitq);
716 }
717 
718 /**
719  * tipc_node_link_up - handle addition of link
720  *
721  * Link becomes active (alone or shared) or standby, depending on its priority.
722  */
723 static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
724 			      struct sk_buff_head *xmitq)
725 {
726 	struct tipc_media_addr *maddr;
727 
728 	tipc_node_write_lock(n);
729 	__tipc_node_link_up(n, bearer_id, xmitq);
730 	maddr = &n->links[bearer_id].maddr;
731 	tipc_bearer_xmit(n->net, bearer_id, xmitq, maddr);
732 	tipc_node_write_unlock(n);
733 }
734 
735 /**
736  * __tipc_node_link_down - handle loss of link
737  */
738 static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
739 				  struct sk_buff_head *xmitq,
740 				  struct tipc_media_addr **maddr)
741 {
742 	struct tipc_link_entry *le = &n->links[*bearer_id];
743 	int *slot0 = &n->active_links[0];
744 	int *slot1 = &n->active_links[1];
745 	int i, highest = 0, prio;
746 	struct tipc_link *l, *_l, *tnl;
747 
748 	l = n->links[*bearer_id].link;
749 	if (!l || tipc_link_is_reset(l))
750 		return;
751 
752 	n->working_links--;
753 	n->action_flags |= TIPC_NOTIFY_LINK_DOWN;
754 	n->link_id = tipc_link_id(l);
755 
756 	tipc_bearer_remove_dest(n->net, *bearer_id, n->addr);
757 
758 	pr_debug("Lost link <%s> on network plane %c\n",
759 		 tipc_link_name(l), tipc_link_plane(l));
760 
761 	/* Select new active link if any available */
762 	*slot0 = INVALID_BEARER_ID;
763 	*slot1 = INVALID_BEARER_ID;
764 	for (i = 0; i < MAX_BEARERS; i++) {
765 		_l = n->links[i].link;
766 		if (!_l || !tipc_link_is_up(_l))
767 			continue;
768 		if (_l == l)
769 			continue;
770 		prio = tipc_link_prio(_l);
771 		if (prio < highest)
772 			continue;
773 		if (prio > highest) {
774 			highest = prio;
775 			*slot0 = i;
776 			*slot1 = i;
777 			continue;
778 		}
779 		*slot1 = i;
780 	}
781 
782 	if (!node_is_up(n)) {
783 		if (tipc_link_peer_is_down(l))
784 			tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
785 		tipc_node_fsm_evt(n, SELF_LOST_CONTACT_EVT);
786 		tipc_link_fsm_evt(l, LINK_RESET_EVT);
787 		tipc_link_reset(l);
788 		tipc_link_build_reset_msg(l, xmitq);
789 		*maddr = &n->links[*bearer_id].maddr;
790 		node_lost_contact(n, &le->inputq);
791 		tipc_bcast_dec_bearer_dst_cnt(n->net, *bearer_id);
792 		return;
793 	}
794 	tipc_bcast_dec_bearer_dst_cnt(n->net, *bearer_id);
795 
796 	/* There is still a working link => initiate failover */
797 	*bearer_id = n->active_links[0];
798 	tnl = n->links[*bearer_id].link;
799 	tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
800 	tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
801 	n->sync_point = tipc_link_rcv_nxt(tnl) + (U16_MAX / 2 - 1);
802 	tipc_link_tnl_prepare(l, tnl, FAILOVER_MSG, xmitq);
803 	tipc_link_reset(l);
804 	tipc_link_fsm_evt(l, LINK_RESET_EVT);
805 	tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
806 	tipc_node_fsm_evt(n, NODE_FAILOVER_BEGIN_EVT);
807 	*maddr = &n->links[*bearer_id].maddr;
808 }
809 
810 static void tipc_node_link_down(struct tipc_node *n, int bearer_id, bool delete)
811 {
812 	struct tipc_link_entry *le = &n->links[bearer_id];
813 	struct tipc_link *l = le->link;
814 	struct tipc_media_addr *maddr;
815 	struct sk_buff_head xmitq;
816 	int old_bearer_id = bearer_id;
817 
818 	if (!l)
819 		return;
820 
821 	__skb_queue_head_init(&xmitq);
822 
823 	tipc_node_write_lock(n);
824 	if (!tipc_link_is_establishing(l)) {
825 		__tipc_node_link_down(n, &bearer_id, &xmitq, &maddr);
826 		if (delete) {
827 			kfree(l);
828 			le->link = NULL;
829 			n->link_cnt--;
830 		}
831 	} else {
832 		/* Defuse pending tipc_node_link_up() */
833 		tipc_link_fsm_evt(l, LINK_RESET_EVT);
834 	}
835 	tipc_node_write_unlock(n);
836 	if (delete)
837 		tipc_mon_remove_peer(n->net, n->addr, old_bearer_id);
838 	tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
839 	tipc_sk_rcv(n->net, &le->inputq);
840 }
841 
842 static bool node_is_up(struct tipc_node *n)
843 {
844 	return n->active_links[0] != INVALID_BEARER_ID;
845 }
846 
847 bool tipc_node_is_up(struct net *net, u32 addr)
848 {
849 	struct tipc_node *n;
850 	bool retval = false;
851 
852 	if (in_own_node(net, addr))
853 		return true;
854 
855 	n = tipc_node_find(net, addr);
856 	if (!n)
857 		return false;
858 	retval = node_is_up(n);
859 	tipc_node_put(n);
860 	return retval;
861 }
862 
863 static u32 tipc_node_suggest_addr(struct net *net, u32 addr)
864 {
865 	struct tipc_node *n;
866 
867 	addr ^= tipc_net(net)->random;
868 	while ((n = tipc_node_find(net, addr))) {
869 		tipc_node_put(n);
870 		addr++;
871 	}
872 	return addr;
873 }
874 
875 /* tipc_node_try_addr(): Check if addr can be used by peer, suggest other if not
876  * Returns suggested address if any, otherwise 0
877  */
878 u32 tipc_node_try_addr(struct net *net, u8 *id, u32 addr)
879 {
880 	struct tipc_net *tn = tipc_net(net);
881 	struct tipc_node *n;
882 
883 	/* Suggest new address if some other peer is using this one */
884 	n = tipc_node_find(net, addr);
885 	if (n) {
886 		if (!memcmp(n->peer_id, id, NODE_ID_LEN))
887 			addr = 0;
888 		tipc_node_put(n);
889 		if (!addr)
890 			return 0;
891 		return tipc_node_suggest_addr(net, addr);
892 	}
893 
894 	/* Suggest previously used address if peer is known */
895 	n = tipc_node_find_by_id(net, id);
896 	if (n) {
897 		addr = n->addr;
898 		tipc_node_put(n);
899 		return addr;
900 	}
901 
902 	/* Even this node may be in conflict */
903 	if (tn->trial_addr == addr)
904 		return tipc_node_suggest_addr(net, addr);
905 
906 	return 0;
907 }
908 
909 void tipc_node_check_dest(struct net *net, u32 addr,
910 			  u8 *peer_id, struct tipc_bearer *b,
911 			  u16 capabilities, u32 signature,
912 			  struct tipc_media_addr *maddr,
913 			  bool *respond, bool *dupl_addr)
914 {
915 	struct tipc_node *n;
916 	struct tipc_link *l;
917 	struct tipc_link_entry *le;
918 	bool addr_match = false;
919 	bool sign_match = false;
920 	bool link_up = false;
921 	bool accept_addr = false;
922 	bool reset = true;
923 	char *if_name;
924 	unsigned long intv;
925 	u16 session;
926 
927 	*dupl_addr = false;
928 	*respond = false;
929 
930 	n = tipc_node_create(net, addr, peer_id, capabilities);
931 	if (!n)
932 		return;
933 
934 	tipc_node_write_lock(n);
935 
936 	le = &n->links[b->identity];
937 
938 	/* Prepare to validate requesting node's signature and media address */
939 	l = le->link;
940 	link_up = l && tipc_link_is_up(l);
941 	addr_match = l && !memcmp(&le->maddr, maddr, sizeof(*maddr));
942 	sign_match = (signature == n->signature);
943 
944 	/* These three flags give us eight permutations: */
945 
946 	if (sign_match && addr_match && link_up) {
947 		/* All is fine. Do nothing. */
948 		reset = false;
949 	} else if (sign_match && addr_match && !link_up) {
950 		/* Respond. The link will come up in due time */
951 		*respond = true;
952 	} else if (sign_match && !addr_match && link_up) {
953 		/* Peer has changed i/f address without rebooting.
954 		 * If so, the link will reset soon, and the next
955 		 * discovery will be accepted. So we can ignore it.
956 		 * It may also be an cloned or malicious peer having
957 		 * chosen the same node address and signature as an
958 		 * existing one.
959 		 * Ignore requests until the link goes down, if ever.
960 		 */
961 		*dupl_addr = true;
962 	} else if (sign_match && !addr_match && !link_up) {
963 		/* Peer link has changed i/f address without rebooting.
964 		 * It may also be a cloned or malicious peer; we can't
965 		 * distinguish between the two.
966 		 * The signature is correct, so we must accept.
967 		 */
968 		accept_addr = true;
969 		*respond = true;
970 	} else if (!sign_match && addr_match && link_up) {
971 		/* Peer node rebooted. Two possibilities:
972 		 *  - Delayed re-discovery; this link endpoint has already
973 		 *    reset and re-established contact with the peer, before
974 		 *    receiving a discovery message from that node.
975 		 *    (The peer happened to receive one from this node first).
976 		 *  - The peer came back so fast that our side has not
977 		 *    discovered it yet. Probing from this side will soon
978 		 *    reset the link, since there can be no working link
979 		 *    endpoint at the peer end, and the link will re-establish.
980 		 *  Accept the signature, since it comes from a known peer.
981 		 */
982 		n->signature = signature;
983 	} else if (!sign_match && addr_match && !link_up) {
984 		/*  The peer node has rebooted.
985 		 *  Accept signature, since it is a known peer.
986 		 */
987 		n->signature = signature;
988 		*respond = true;
989 	} else if (!sign_match && !addr_match && link_up) {
990 		/* Peer rebooted with new address, or a new/duplicate peer.
991 		 * Ignore until the link goes down, if ever.
992 		 */
993 		*dupl_addr = true;
994 	} else if (!sign_match && !addr_match && !link_up) {
995 		/* Peer rebooted with new address, or it is a new peer.
996 		 * Accept signature and address.
997 		 */
998 		n->signature = signature;
999 		accept_addr = true;
1000 		*respond = true;
1001 	}
1002 
1003 	if (!accept_addr)
1004 		goto exit;
1005 
1006 	/* Now create new link if not already existing */
1007 	if (!l) {
1008 		if (n->link_cnt == 2)
1009 			goto exit;
1010 
1011 		if_name = strchr(b->name, ':') + 1;
1012 		get_random_bytes(&session, sizeof(u16));
1013 		if (!tipc_link_create(net, if_name, b->identity, b->tolerance,
1014 				      b->net_plane, b->mtu, b->priority,
1015 				      b->window, session,
1016 				      tipc_own_addr(net), addr, peer_id,
1017 				      n->capabilities,
1018 				      tipc_bc_sndlink(n->net), n->bc_entry.link,
1019 				      &le->inputq,
1020 				      &n->bc_entry.namedq, &l)) {
1021 			*respond = false;
1022 			goto exit;
1023 		}
1024 		tipc_link_reset(l);
1025 		tipc_link_fsm_evt(l, LINK_RESET_EVT);
1026 		if (n->state == NODE_FAILINGOVER)
1027 			tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
1028 		le->link = l;
1029 		n->link_cnt++;
1030 		tipc_node_calculate_timer(n, l);
1031 		if (n->link_cnt == 1) {
1032 			intv = jiffies + msecs_to_jiffies(n->keepalive_intv);
1033 			if (!mod_timer(&n->timer, intv))
1034 				tipc_node_get(n);
1035 		}
1036 	}
1037 	memcpy(&le->maddr, maddr, sizeof(*maddr));
1038 exit:
1039 	tipc_node_write_unlock(n);
1040 	if (reset && l && !tipc_link_is_reset(l))
1041 		tipc_node_link_down(n, b->identity, false);
1042 	tipc_node_put(n);
1043 }
1044 
1045 void tipc_node_delete_links(struct net *net, int bearer_id)
1046 {
1047 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1048 	struct tipc_node *n;
1049 
1050 	rcu_read_lock();
1051 	list_for_each_entry_rcu(n, &tn->node_list, list) {
1052 		tipc_node_link_down(n, bearer_id, true);
1053 	}
1054 	rcu_read_unlock();
1055 }
1056 
1057 static void tipc_node_reset_links(struct tipc_node *n)
1058 {
1059 	int i;
1060 
1061 	pr_warn("Resetting all links to %x\n", n->addr);
1062 
1063 	for (i = 0; i < MAX_BEARERS; i++) {
1064 		tipc_node_link_down(n, i, false);
1065 	}
1066 }
1067 
1068 /* tipc_node_fsm_evt - node finite state machine
1069  * Determines when contact is allowed with peer node
1070  */
1071 static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
1072 {
1073 	int state = n->state;
1074 
1075 	switch (state) {
1076 	case SELF_DOWN_PEER_DOWN:
1077 		switch (evt) {
1078 		case SELF_ESTABL_CONTACT_EVT:
1079 			state = SELF_UP_PEER_COMING;
1080 			break;
1081 		case PEER_ESTABL_CONTACT_EVT:
1082 			state = SELF_COMING_PEER_UP;
1083 			break;
1084 		case SELF_LOST_CONTACT_EVT:
1085 		case PEER_LOST_CONTACT_EVT:
1086 			break;
1087 		case NODE_SYNCH_END_EVT:
1088 		case NODE_SYNCH_BEGIN_EVT:
1089 		case NODE_FAILOVER_BEGIN_EVT:
1090 		case NODE_FAILOVER_END_EVT:
1091 		default:
1092 			goto illegal_evt;
1093 		}
1094 		break;
1095 	case SELF_UP_PEER_UP:
1096 		switch (evt) {
1097 		case SELF_LOST_CONTACT_EVT:
1098 			state = SELF_DOWN_PEER_LEAVING;
1099 			break;
1100 		case PEER_LOST_CONTACT_EVT:
1101 			state = SELF_LEAVING_PEER_DOWN;
1102 			break;
1103 		case NODE_SYNCH_BEGIN_EVT:
1104 			state = NODE_SYNCHING;
1105 			break;
1106 		case NODE_FAILOVER_BEGIN_EVT:
1107 			state = NODE_FAILINGOVER;
1108 			break;
1109 		case SELF_ESTABL_CONTACT_EVT:
1110 		case PEER_ESTABL_CONTACT_EVT:
1111 		case NODE_SYNCH_END_EVT:
1112 		case NODE_FAILOVER_END_EVT:
1113 			break;
1114 		default:
1115 			goto illegal_evt;
1116 		}
1117 		break;
1118 	case SELF_DOWN_PEER_LEAVING:
1119 		switch (evt) {
1120 		case PEER_LOST_CONTACT_EVT:
1121 			state = SELF_DOWN_PEER_DOWN;
1122 			break;
1123 		case SELF_ESTABL_CONTACT_EVT:
1124 		case PEER_ESTABL_CONTACT_EVT:
1125 		case SELF_LOST_CONTACT_EVT:
1126 			break;
1127 		case NODE_SYNCH_END_EVT:
1128 		case NODE_SYNCH_BEGIN_EVT:
1129 		case NODE_FAILOVER_BEGIN_EVT:
1130 		case NODE_FAILOVER_END_EVT:
1131 		default:
1132 			goto illegal_evt;
1133 		}
1134 		break;
1135 	case SELF_UP_PEER_COMING:
1136 		switch (evt) {
1137 		case PEER_ESTABL_CONTACT_EVT:
1138 			state = SELF_UP_PEER_UP;
1139 			break;
1140 		case SELF_LOST_CONTACT_EVT:
1141 			state = SELF_DOWN_PEER_DOWN;
1142 			break;
1143 		case SELF_ESTABL_CONTACT_EVT:
1144 		case PEER_LOST_CONTACT_EVT:
1145 		case NODE_SYNCH_END_EVT:
1146 		case NODE_FAILOVER_BEGIN_EVT:
1147 			break;
1148 		case NODE_SYNCH_BEGIN_EVT:
1149 		case NODE_FAILOVER_END_EVT:
1150 		default:
1151 			goto illegal_evt;
1152 		}
1153 		break;
1154 	case SELF_COMING_PEER_UP:
1155 		switch (evt) {
1156 		case SELF_ESTABL_CONTACT_EVT:
1157 			state = SELF_UP_PEER_UP;
1158 			break;
1159 		case PEER_LOST_CONTACT_EVT:
1160 			state = SELF_DOWN_PEER_DOWN;
1161 			break;
1162 		case SELF_LOST_CONTACT_EVT:
1163 		case PEER_ESTABL_CONTACT_EVT:
1164 			break;
1165 		case NODE_SYNCH_END_EVT:
1166 		case NODE_SYNCH_BEGIN_EVT:
1167 		case NODE_FAILOVER_BEGIN_EVT:
1168 		case NODE_FAILOVER_END_EVT:
1169 		default:
1170 			goto illegal_evt;
1171 		}
1172 		break;
1173 	case SELF_LEAVING_PEER_DOWN:
1174 		switch (evt) {
1175 		case SELF_LOST_CONTACT_EVT:
1176 			state = SELF_DOWN_PEER_DOWN;
1177 			break;
1178 		case SELF_ESTABL_CONTACT_EVT:
1179 		case PEER_ESTABL_CONTACT_EVT:
1180 		case PEER_LOST_CONTACT_EVT:
1181 			break;
1182 		case NODE_SYNCH_END_EVT:
1183 		case NODE_SYNCH_BEGIN_EVT:
1184 		case NODE_FAILOVER_BEGIN_EVT:
1185 		case NODE_FAILOVER_END_EVT:
1186 		default:
1187 			goto illegal_evt;
1188 		}
1189 		break;
1190 	case NODE_FAILINGOVER:
1191 		switch (evt) {
1192 		case SELF_LOST_CONTACT_EVT:
1193 			state = SELF_DOWN_PEER_LEAVING;
1194 			break;
1195 		case PEER_LOST_CONTACT_EVT:
1196 			state = SELF_LEAVING_PEER_DOWN;
1197 			break;
1198 		case NODE_FAILOVER_END_EVT:
1199 			state = SELF_UP_PEER_UP;
1200 			break;
1201 		case NODE_FAILOVER_BEGIN_EVT:
1202 		case SELF_ESTABL_CONTACT_EVT:
1203 		case PEER_ESTABL_CONTACT_EVT:
1204 			break;
1205 		case NODE_SYNCH_BEGIN_EVT:
1206 		case NODE_SYNCH_END_EVT:
1207 		default:
1208 			goto illegal_evt;
1209 		}
1210 		break;
1211 	case NODE_SYNCHING:
1212 		switch (evt) {
1213 		case SELF_LOST_CONTACT_EVT:
1214 			state = SELF_DOWN_PEER_LEAVING;
1215 			break;
1216 		case PEER_LOST_CONTACT_EVT:
1217 			state = SELF_LEAVING_PEER_DOWN;
1218 			break;
1219 		case NODE_SYNCH_END_EVT:
1220 			state = SELF_UP_PEER_UP;
1221 			break;
1222 		case NODE_FAILOVER_BEGIN_EVT:
1223 			state = NODE_FAILINGOVER;
1224 			break;
1225 		case NODE_SYNCH_BEGIN_EVT:
1226 		case SELF_ESTABL_CONTACT_EVT:
1227 		case PEER_ESTABL_CONTACT_EVT:
1228 			break;
1229 		case NODE_FAILOVER_END_EVT:
1230 		default:
1231 			goto illegal_evt;
1232 		}
1233 		break;
1234 	default:
1235 		pr_err("Unknown node fsm state %x\n", state);
1236 		break;
1237 	}
1238 	n->state = state;
1239 	return;
1240 
1241 illegal_evt:
1242 	pr_err("Illegal node fsm evt %x in state %x\n", evt, state);
1243 }
1244 
1245 static void node_lost_contact(struct tipc_node *n,
1246 			      struct sk_buff_head *inputq)
1247 {
1248 	struct tipc_sock_conn *conn, *safe;
1249 	struct tipc_link *l;
1250 	struct list_head *conns = &n->conn_sks;
1251 	struct sk_buff *skb;
1252 	uint i;
1253 
1254 	pr_debug("Lost contact with %x\n", n->addr);
1255 	n->delete_at = jiffies + msecs_to_jiffies(NODE_CLEANUP_AFTER);
1256 
1257 	/* Clean up broadcast state */
1258 	tipc_bcast_remove_peer(n->net, n->bc_entry.link);
1259 
1260 	/* Abort any ongoing link failover */
1261 	for (i = 0; i < MAX_BEARERS; i++) {
1262 		l = n->links[i].link;
1263 		if (l)
1264 			tipc_link_fsm_evt(l, LINK_FAILOVER_END_EVT);
1265 	}
1266 
1267 	/* Notify publications from this node */
1268 	n->action_flags |= TIPC_NOTIFY_NODE_DOWN;
1269 
1270 	/* Notify sockets connected to node */
1271 	list_for_each_entry_safe(conn, safe, conns, list) {
1272 		skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG,
1273 				      SHORT_H_SIZE, 0, tipc_own_addr(n->net),
1274 				      conn->peer_node, conn->port,
1275 				      conn->peer_port, TIPC_ERR_NO_NODE);
1276 		if (likely(skb))
1277 			skb_queue_tail(inputq, skb);
1278 		list_del(&conn->list);
1279 		kfree(conn);
1280 	}
1281 }
1282 
1283 /**
1284  * tipc_node_get_linkname - get the name of a link
1285  *
1286  * @bearer_id: id of the bearer
1287  * @node: peer node address
1288  * @linkname: link name output buffer
1289  *
1290  * Returns 0 on success
1291  */
1292 int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 addr,
1293 			   char *linkname, size_t len)
1294 {
1295 	struct tipc_link *link;
1296 	int err = -EINVAL;
1297 	struct tipc_node *node = tipc_node_find(net, addr);
1298 
1299 	if (!node)
1300 		return err;
1301 
1302 	if (bearer_id >= MAX_BEARERS)
1303 		goto exit;
1304 
1305 	tipc_node_read_lock(node);
1306 	link = node->links[bearer_id].link;
1307 	if (link) {
1308 		strncpy(linkname, tipc_link_name(link), len);
1309 		err = 0;
1310 	}
1311 	tipc_node_read_unlock(node);
1312 exit:
1313 	tipc_node_put(node);
1314 	return err;
1315 }
1316 
1317 /* Caller should hold node lock for the passed node */
1318 static int __tipc_nl_add_node(struct tipc_nl_msg *msg, struct tipc_node *node)
1319 {
1320 	void *hdr;
1321 	struct nlattr *attrs;
1322 
1323 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1324 			  NLM_F_MULTI, TIPC_NL_NODE_GET);
1325 	if (!hdr)
1326 		return -EMSGSIZE;
1327 
1328 	attrs = nla_nest_start(msg->skb, TIPC_NLA_NODE);
1329 	if (!attrs)
1330 		goto msg_full;
1331 
1332 	if (nla_put_u32(msg->skb, TIPC_NLA_NODE_ADDR, node->addr))
1333 		goto attr_msg_full;
1334 	if (node_is_up(node))
1335 		if (nla_put_flag(msg->skb, TIPC_NLA_NODE_UP))
1336 			goto attr_msg_full;
1337 
1338 	nla_nest_end(msg->skb, attrs);
1339 	genlmsg_end(msg->skb, hdr);
1340 
1341 	return 0;
1342 
1343 attr_msg_full:
1344 	nla_nest_cancel(msg->skb, attrs);
1345 msg_full:
1346 	genlmsg_cancel(msg->skb, hdr);
1347 
1348 	return -EMSGSIZE;
1349 }
1350 
1351 /**
1352  * tipc_node_xmit() is the general link level function for message sending
1353  * @net: the applicable net namespace
1354  * @list: chain of buffers containing message
1355  * @dnode: address of destination node
1356  * @selector: a number used for deterministic link selection
1357  * Consumes the buffer chain.
1358  * Returns 0 if success, otherwise: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE,-ENOBUF
1359  */
1360 int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
1361 		   u32 dnode, int selector)
1362 {
1363 	struct tipc_link_entry *le = NULL;
1364 	struct tipc_node *n;
1365 	struct sk_buff_head xmitq;
1366 	int bearer_id;
1367 	int rc;
1368 
1369 	if (in_own_node(net, dnode)) {
1370 		tipc_sk_rcv(net, list);
1371 		return 0;
1372 	}
1373 
1374 	n = tipc_node_find(net, dnode);
1375 	if (unlikely(!n)) {
1376 		skb_queue_purge(list);
1377 		return -EHOSTUNREACH;
1378 	}
1379 
1380 	tipc_node_read_lock(n);
1381 	bearer_id = n->active_links[selector & 1];
1382 	if (unlikely(bearer_id == INVALID_BEARER_ID)) {
1383 		tipc_node_read_unlock(n);
1384 		tipc_node_put(n);
1385 		skb_queue_purge(list);
1386 		return -EHOSTUNREACH;
1387 	}
1388 
1389 	__skb_queue_head_init(&xmitq);
1390 	le = &n->links[bearer_id];
1391 	spin_lock_bh(&le->lock);
1392 	rc = tipc_link_xmit(le->link, list, &xmitq);
1393 	spin_unlock_bh(&le->lock);
1394 	tipc_node_read_unlock(n);
1395 
1396 	if (unlikely(rc == -ENOBUFS))
1397 		tipc_node_link_down(n, bearer_id, false);
1398 	else
1399 		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1400 
1401 	tipc_node_put(n);
1402 
1403 	return rc;
1404 }
1405 
1406 /* tipc_node_xmit_skb(): send single buffer to destination
1407  * Buffers sent via this functon are generally TIPC_SYSTEM_IMPORTANCE
1408  * messages, which will not be rejected
1409  * The only exception is datagram messages rerouted after secondary
1410  * lookup, which are rare and safe to dispose of anyway.
1411  */
1412 int tipc_node_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
1413 		       u32 selector)
1414 {
1415 	struct sk_buff_head head;
1416 
1417 	skb_queue_head_init(&head);
1418 	__skb_queue_tail(&head, skb);
1419 	tipc_node_xmit(net, &head, dnode, selector);
1420 	return 0;
1421 }
1422 
1423 /* tipc_node_distr_xmit(): send single buffer msgs to individual destinations
1424  * Note: this is only for SYSTEM_IMPORTANCE messages, which cannot be rejected
1425  */
1426 int tipc_node_distr_xmit(struct net *net, struct sk_buff_head *xmitq)
1427 {
1428 	struct sk_buff *skb;
1429 	u32 selector, dnode;
1430 
1431 	while ((skb = __skb_dequeue(xmitq))) {
1432 		selector = msg_origport(buf_msg(skb));
1433 		dnode = msg_destnode(buf_msg(skb));
1434 		tipc_node_xmit_skb(net, skb, dnode, selector);
1435 	}
1436 	return 0;
1437 }
1438 
1439 void tipc_node_broadcast(struct net *net, struct sk_buff *skb)
1440 {
1441 	struct sk_buff *txskb;
1442 	struct tipc_node *n;
1443 	u32 dst;
1444 
1445 	rcu_read_lock();
1446 	list_for_each_entry_rcu(n, tipc_nodes(net), list) {
1447 		dst = n->addr;
1448 		if (in_own_node(net, dst))
1449 			continue;
1450 		if (!node_is_up(n))
1451 			continue;
1452 		txskb = pskb_copy(skb, GFP_ATOMIC);
1453 		if (!txskb)
1454 			break;
1455 		msg_set_destnode(buf_msg(txskb), dst);
1456 		tipc_node_xmit_skb(net, txskb, dst, 0);
1457 	}
1458 	rcu_read_unlock();
1459 
1460 	kfree_skb(skb);
1461 }
1462 
1463 static void tipc_node_mcast_rcv(struct tipc_node *n)
1464 {
1465 	struct tipc_bclink_entry *be = &n->bc_entry;
1466 
1467 	/* 'arrvq' is under inputq2's lock protection */
1468 	spin_lock_bh(&be->inputq2.lock);
1469 	spin_lock_bh(&be->inputq1.lock);
1470 	skb_queue_splice_tail_init(&be->inputq1, &be->arrvq);
1471 	spin_unlock_bh(&be->inputq1.lock);
1472 	spin_unlock_bh(&be->inputq2.lock);
1473 	tipc_sk_mcast_rcv(n->net, &be->arrvq, &be->inputq2);
1474 }
1475 
1476 static void tipc_node_bc_sync_rcv(struct tipc_node *n, struct tipc_msg *hdr,
1477 				  int bearer_id, struct sk_buff_head *xmitq)
1478 {
1479 	struct tipc_link *ucl;
1480 	int rc;
1481 
1482 	rc = tipc_bcast_sync_rcv(n->net, n->bc_entry.link, hdr);
1483 
1484 	if (rc & TIPC_LINK_DOWN_EVT) {
1485 		tipc_node_reset_links(n);
1486 		return;
1487 	}
1488 
1489 	if (!(rc & TIPC_LINK_SND_STATE))
1490 		return;
1491 
1492 	/* If probe message, a STATE response will be sent anyway */
1493 	if (msg_probe(hdr))
1494 		return;
1495 
1496 	/* Produce a STATE message carrying broadcast NACK */
1497 	tipc_node_read_lock(n);
1498 	ucl = n->links[bearer_id].link;
1499 	if (ucl)
1500 		tipc_link_build_state_msg(ucl, xmitq);
1501 	tipc_node_read_unlock(n);
1502 }
1503 
1504 /**
1505  * tipc_node_bc_rcv - process TIPC broadcast packet arriving from off-node
1506  * @net: the applicable net namespace
1507  * @skb: TIPC packet
1508  * @bearer_id: id of bearer message arrived on
1509  *
1510  * Invoked with no locks held.
1511  */
1512 static void tipc_node_bc_rcv(struct net *net, struct sk_buff *skb, int bearer_id)
1513 {
1514 	int rc;
1515 	struct sk_buff_head xmitq;
1516 	struct tipc_bclink_entry *be;
1517 	struct tipc_link_entry *le;
1518 	struct tipc_msg *hdr = buf_msg(skb);
1519 	int usr = msg_user(hdr);
1520 	u32 dnode = msg_destnode(hdr);
1521 	struct tipc_node *n;
1522 
1523 	__skb_queue_head_init(&xmitq);
1524 
1525 	/* If NACK for other node, let rcv link for that node peek into it */
1526 	if ((usr == BCAST_PROTOCOL) && (dnode != tipc_own_addr(net)))
1527 		n = tipc_node_find(net, dnode);
1528 	else
1529 		n = tipc_node_find(net, msg_prevnode(hdr));
1530 	if (!n) {
1531 		kfree_skb(skb);
1532 		return;
1533 	}
1534 	be = &n->bc_entry;
1535 	le = &n->links[bearer_id];
1536 
1537 	rc = tipc_bcast_rcv(net, be->link, skb);
1538 
1539 	/* Broadcast ACKs are sent on a unicast link */
1540 	if (rc & TIPC_LINK_SND_STATE) {
1541 		tipc_node_read_lock(n);
1542 		tipc_link_build_state_msg(le->link, &xmitq);
1543 		tipc_node_read_unlock(n);
1544 	}
1545 
1546 	if (!skb_queue_empty(&xmitq))
1547 		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1548 
1549 	if (!skb_queue_empty(&be->inputq1))
1550 		tipc_node_mcast_rcv(n);
1551 
1552 	/* If reassembly or retransmission failure => reset all links to peer */
1553 	if (rc & TIPC_LINK_DOWN_EVT)
1554 		tipc_node_reset_links(n);
1555 
1556 	tipc_node_put(n);
1557 }
1558 
1559 /**
1560  * tipc_node_check_state - check and if necessary update node state
1561  * @skb: TIPC packet
1562  * @bearer_id: identity of bearer delivering the packet
1563  * Returns true if state and msg are ok, otherwise false
1564  */
1565 static bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
1566 				  int bearer_id, struct sk_buff_head *xmitq)
1567 {
1568 	struct tipc_msg *hdr = buf_msg(skb);
1569 	int usr = msg_user(hdr);
1570 	int mtyp = msg_type(hdr);
1571 	u16 oseqno = msg_seqno(hdr);
1572 	u16 iseqno = msg_seqno(msg_get_wrapped(hdr));
1573 	u16 exp_pkts = msg_msgcnt(hdr);
1574 	u16 rcv_nxt, syncpt, dlv_nxt, inputq_len;
1575 	int state = n->state;
1576 	struct tipc_link *l, *tnl, *pl = NULL;
1577 	struct tipc_media_addr *maddr;
1578 	int pb_id;
1579 
1580 	l = n->links[bearer_id].link;
1581 	if (!l)
1582 		return false;
1583 	rcv_nxt = tipc_link_rcv_nxt(l);
1584 
1585 
1586 	if (likely((state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL)))
1587 		return true;
1588 
1589 	/* Find parallel link, if any */
1590 	for (pb_id = 0; pb_id < MAX_BEARERS; pb_id++) {
1591 		if ((pb_id != bearer_id) && n->links[pb_id].link) {
1592 			pl = n->links[pb_id].link;
1593 			break;
1594 		}
1595 	}
1596 
1597 	if (!tipc_link_validate_msg(l, hdr))
1598 		return false;
1599 
1600 	/* Check and update node accesibility if applicable */
1601 	if (state == SELF_UP_PEER_COMING) {
1602 		if (!tipc_link_is_up(l))
1603 			return true;
1604 		if (!msg_peer_link_is_up(hdr))
1605 			return true;
1606 		tipc_node_fsm_evt(n, PEER_ESTABL_CONTACT_EVT);
1607 	}
1608 
1609 	if (state == SELF_DOWN_PEER_LEAVING) {
1610 		if (msg_peer_node_is_up(hdr))
1611 			return false;
1612 		tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
1613 		return true;
1614 	}
1615 
1616 	if (state == SELF_LEAVING_PEER_DOWN)
1617 		return false;
1618 
1619 	/* Ignore duplicate packets */
1620 	if ((usr != LINK_PROTOCOL) && less(oseqno, rcv_nxt))
1621 		return true;
1622 
1623 	/* Initiate or update failover mode if applicable */
1624 	if ((usr == TUNNEL_PROTOCOL) && (mtyp == FAILOVER_MSG)) {
1625 		syncpt = oseqno + exp_pkts - 1;
1626 		if (pl && tipc_link_is_up(pl)) {
1627 			__tipc_node_link_down(n, &pb_id, xmitq, &maddr);
1628 			tipc_skb_queue_splice_tail_init(tipc_link_inputq(pl),
1629 							tipc_link_inputq(l));
1630 		}
1631 		/* If parallel link was already down, and this happened before
1632 		 * the tunnel link came up, FAILOVER was never sent. Ensure that
1633 		 * FAILOVER is sent to get peer out of NODE_FAILINGOVER state.
1634 		 */
1635 		if (n->state != NODE_FAILINGOVER && !n->failover_sent) {
1636 			tipc_link_create_dummy_tnl_msg(l, xmitq);
1637 			n->failover_sent = true;
1638 		}
1639 		/* If pkts arrive out of order, use lowest calculated syncpt */
1640 		if (less(syncpt, n->sync_point))
1641 			n->sync_point = syncpt;
1642 	}
1643 
1644 	/* Open parallel link when tunnel link reaches synch point */
1645 	if ((n->state == NODE_FAILINGOVER) && tipc_link_is_up(l)) {
1646 		if (!more(rcv_nxt, n->sync_point))
1647 			return true;
1648 		tipc_node_fsm_evt(n, NODE_FAILOVER_END_EVT);
1649 		if (pl)
1650 			tipc_link_fsm_evt(pl, LINK_FAILOVER_END_EVT);
1651 		return true;
1652 	}
1653 
1654 	/* No synching needed if only one link */
1655 	if (!pl || !tipc_link_is_up(pl))
1656 		return true;
1657 
1658 	/* Initiate synch mode if applicable */
1659 	if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG) && (oseqno == 1)) {
1660 		syncpt = iseqno + exp_pkts - 1;
1661 		if (!tipc_link_is_up(l))
1662 			__tipc_node_link_up(n, bearer_id, xmitq);
1663 		if (n->state == SELF_UP_PEER_UP) {
1664 			n->sync_point = syncpt;
1665 			tipc_link_fsm_evt(l, LINK_SYNCH_BEGIN_EVT);
1666 			tipc_node_fsm_evt(n, NODE_SYNCH_BEGIN_EVT);
1667 		}
1668 	}
1669 
1670 	/* Open tunnel link when parallel link reaches synch point */
1671 	if (n->state == NODE_SYNCHING) {
1672 		if (tipc_link_is_synching(l)) {
1673 			tnl = l;
1674 		} else {
1675 			tnl = pl;
1676 			pl = l;
1677 		}
1678 		inputq_len = skb_queue_len(tipc_link_inputq(pl));
1679 		dlv_nxt = tipc_link_rcv_nxt(pl) - inputq_len;
1680 		if (more(dlv_nxt, n->sync_point)) {
1681 			tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
1682 			tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
1683 			return true;
1684 		}
1685 		if (l == pl)
1686 			return true;
1687 		if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG))
1688 			return true;
1689 		if (usr == LINK_PROTOCOL)
1690 			return true;
1691 		return false;
1692 	}
1693 	return true;
1694 }
1695 
1696 /**
1697  * tipc_rcv - process TIPC packets/messages arriving from off-node
1698  * @net: the applicable net namespace
1699  * @skb: TIPC packet
1700  * @bearer: pointer to bearer message arrived on
1701  *
1702  * Invoked with no locks held. Bearer pointer must point to a valid bearer
1703  * structure (i.e. cannot be NULL), but bearer can be inactive.
1704  */
1705 void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
1706 {
1707 	struct sk_buff_head xmitq;
1708 	struct tipc_node *n;
1709 	struct tipc_msg *hdr;
1710 	int bearer_id = b->identity;
1711 	struct tipc_link_entry *le;
1712 	u32 self = tipc_own_addr(net);
1713 	int usr, rc = 0;
1714 	u16 bc_ack;
1715 
1716 	__skb_queue_head_init(&xmitq);
1717 
1718 	/* Ensure message is well-formed before touching the header */
1719 	if (unlikely(!tipc_msg_validate(&skb)))
1720 		goto discard;
1721 	hdr = buf_msg(skb);
1722 	usr = msg_user(hdr);
1723 	bc_ack = msg_bcast_ack(hdr);
1724 
1725 	/* Handle arrival of discovery or broadcast packet */
1726 	if (unlikely(msg_non_seq(hdr))) {
1727 		if (unlikely(usr == LINK_CONFIG))
1728 			return tipc_disc_rcv(net, skb, b);
1729 		else
1730 			return tipc_node_bc_rcv(net, skb, bearer_id);
1731 	}
1732 
1733 	/* Discard unicast link messages destined for another node */
1734 	if (unlikely(!msg_short(hdr) && (msg_destnode(hdr) != self)))
1735 		goto discard;
1736 
1737 	/* Locate neighboring node that sent packet */
1738 	n = tipc_node_find(net, msg_prevnode(hdr));
1739 	if (unlikely(!n))
1740 		goto discard;
1741 	le = &n->links[bearer_id];
1742 
1743 	/* Ensure broadcast reception is in synch with peer's send state */
1744 	if (unlikely(usr == LINK_PROTOCOL))
1745 		tipc_node_bc_sync_rcv(n, hdr, bearer_id, &xmitq);
1746 	else if (unlikely(tipc_link_acked(n->bc_entry.link) != bc_ack))
1747 		tipc_bcast_ack_rcv(net, n->bc_entry.link, hdr);
1748 
1749 	/* Receive packet directly if conditions permit */
1750 	tipc_node_read_lock(n);
1751 	if (likely((n->state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL))) {
1752 		spin_lock_bh(&le->lock);
1753 		if (le->link) {
1754 			rc = tipc_link_rcv(le->link, skb, &xmitq);
1755 			skb = NULL;
1756 		}
1757 		spin_unlock_bh(&le->lock);
1758 	}
1759 	tipc_node_read_unlock(n);
1760 
1761 	/* Check/update node state before receiving */
1762 	if (unlikely(skb)) {
1763 		if (unlikely(skb_linearize(skb)))
1764 			goto discard;
1765 		tipc_node_write_lock(n);
1766 		if (tipc_node_check_state(n, skb, bearer_id, &xmitq)) {
1767 			if (le->link) {
1768 				rc = tipc_link_rcv(le->link, skb, &xmitq);
1769 				skb = NULL;
1770 			}
1771 		}
1772 		tipc_node_write_unlock(n);
1773 	}
1774 
1775 	if (unlikely(rc & TIPC_LINK_UP_EVT))
1776 		tipc_node_link_up(n, bearer_id, &xmitq);
1777 
1778 	if (unlikely(rc & TIPC_LINK_DOWN_EVT))
1779 		tipc_node_link_down(n, bearer_id, false);
1780 
1781 	if (unlikely(!skb_queue_empty(&n->bc_entry.namedq)))
1782 		tipc_named_rcv(net, &n->bc_entry.namedq);
1783 
1784 	if (unlikely(!skb_queue_empty(&n->bc_entry.inputq1)))
1785 		tipc_node_mcast_rcv(n);
1786 
1787 	if (!skb_queue_empty(&le->inputq))
1788 		tipc_sk_rcv(net, &le->inputq);
1789 
1790 	if (!skb_queue_empty(&xmitq))
1791 		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1792 
1793 	tipc_node_put(n);
1794 discard:
1795 	kfree_skb(skb);
1796 }
1797 
1798 void tipc_node_apply_property(struct net *net, struct tipc_bearer *b,
1799 			      int prop)
1800 {
1801 	struct tipc_net *tn = tipc_net(net);
1802 	int bearer_id = b->identity;
1803 	struct sk_buff_head xmitq;
1804 	struct tipc_link_entry *e;
1805 	struct tipc_node *n;
1806 
1807 	__skb_queue_head_init(&xmitq);
1808 
1809 	rcu_read_lock();
1810 
1811 	list_for_each_entry_rcu(n, &tn->node_list, list) {
1812 		tipc_node_write_lock(n);
1813 		e = &n->links[bearer_id];
1814 		if (e->link) {
1815 			if (prop == TIPC_NLA_PROP_TOL)
1816 				tipc_link_set_tolerance(e->link, b->tolerance,
1817 							&xmitq);
1818 			else if (prop == TIPC_NLA_PROP_MTU)
1819 				tipc_link_set_mtu(e->link, b->mtu);
1820 		}
1821 		tipc_node_write_unlock(n);
1822 		tipc_bearer_xmit(net, bearer_id, &xmitq, &e->maddr);
1823 	}
1824 
1825 	rcu_read_unlock();
1826 }
1827 
1828 int tipc_nl_peer_rm(struct sk_buff *skb, struct genl_info *info)
1829 {
1830 	struct net *net = sock_net(skb->sk);
1831 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1832 	struct nlattr *attrs[TIPC_NLA_NET_MAX + 1];
1833 	struct tipc_node *peer;
1834 	u32 addr;
1835 	int err;
1836 
1837 	/* We identify the peer by its net */
1838 	if (!info->attrs[TIPC_NLA_NET])
1839 		return -EINVAL;
1840 
1841 	err = nla_parse_nested(attrs, TIPC_NLA_NET_MAX,
1842 			       info->attrs[TIPC_NLA_NET], tipc_nl_net_policy,
1843 			       info->extack);
1844 	if (err)
1845 		return err;
1846 
1847 	if (!attrs[TIPC_NLA_NET_ADDR])
1848 		return -EINVAL;
1849 
1850 	addr = nla_get_u32(attrs[TIPC_NLA_NET_ADDR]);
1851 
1852 	if (in_own_node(net, addr))
1853 		return -ENOTSUPP;
1854 
1855 	spin_lock_bh(&tn->node_list_lock);
1856 	peer = tipc_node_find(net, addr);
1857 	if (!peer) {
1858 		spin_unlock_bh(&tn->node_list_lock);
1859 		return -ENXIO;
1860 	}
1861 
1862 	tipc_node_write_lock(peer);
1863 	if (peer->state != SELF_DOWN_PEER_DOWN &&
1864 	    peer->state != SELF_DOWN_PEER_LEAVING) {
1865 		tipc_node_write_unlock(peer);
1866 		err = -EBUSY;
1867 		goto err_out;
1868 	}
1869 
1870 	tipc_node_clear_links(peer);
1871 	tipc_node_write_unlock(peer);
1872 	tipc_node_delete(peer);
1873 
1874 	err = 0;
1875 err_out:
1876 	tipc_node_put(peer);
1877 	spin_unlock_bh(&tn->node_list_lock);
1878 
1879 	return err;
1880 }
1881 
1882 int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb)
1883 {
1884 	int err;
1885 	struct net *net = sock_net(skb->sk);
1886 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1887 	int done = cb->args[0];
1888 	int last_addr = cb->args[1];
1889 	struct tipc_node *node;
1890 	struct tipc_nl_msg msg;
1891 
1892 	if (done)
1893 		return 0;
1894 
1895 	msg.skb = skb;
1896 	msg.portid = NETLINK_CB(cb->skb).portid;
1897 	msg.seq = cb->nlh->nlmsg_seq;
1898 
1899 	rcu_read_lock();
1900 	if (last_addr) {
1901 		node = tipc_node_find(net, last_addr);
1902 		if (!node) {
1903 			rcu_read_unlock();
1904 			/* We never set seq or call nl_dump_check_consistent()
1905 			 * this means that setting prev_seq here will cause the
1906 			 * consistence check to fail in the netlink callback
1907 			 * handler. Resulting in the NLMSG_DONE message having
1908 			 * the NLM_F_DUMP_INTR flag set if the node state
1909 			 * changed while we released the lock.
1910 			 */
1911 			cb->prev_seq = 1;
1912 			return -EPIPE;
1913 		}
1914 		tipc_node_put(node);
1915 	}
1916 
1917 	list_for_each_entry_rcu(node, &tn->node_list, list) {
1918 		if (last_addr) {
1919 			if (node->addr == last_addr)
1920 				last_addr = 0;
1921 			else
1922 				continue;
1923 		}
1924 
1925 		tipc_node_read_lock(node);
1926 		err = __tipc_nl_add_node(&msg, node);
1927 		if (err) {
1928 			last_addr = node->addr;
1929 			tipc_node_read_unlock(node);
1930 			goto out;
1931 		}
1932 
1933 		tipc_node_read_unlock(node);
1934 	}
1935 	done = 1;
1936 out:
1937 	cb->args[0] = done;
1938 	cb->args[1] = last_addr;
1939 	rcu_read_unlock();
1940 
1941 	return skb->len;
1942 }
1943 
1944 /* tipc_node_find_by_name - locate owner node of link by link's name
1945  * @net: the applicable net namespace
1946  * @name: pointer to link name string
1947  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1948  *
1949  * Returns pointer to node owning the link, or 0 if no matching link is found.
1950  */
1951 static struct tipc_node *tipc_node_find_by_name(struct net *net,
1952 						const char *link_name,
1953 						unsigned int *bearer_id)
1954 {
1955 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1956 	struct tipc_link *l;
1957 	struct tipc_node *n;
1958 	struct tipc_node *found_node = NULL;
1959 	int i;
1960 
1961 	*bearer_id = 0;
1962 	rcu_read_lock();
1963 	list_for_each_entry_rcu(n, &tn->node_list, list) {
1964 		tipc_node_read_lock(n);
1965 		for (i = 0; i < MAX_BEARERS; i++) {
1966 			l = n->links[i].link;
1967 			if (l && !strcmp(tipc_link_name(l), link_name)) {
1968 				*bearer_id = i;
1969 				found_node = n;
1970 				break;
1971 			}
1972 		}
1973 		tipc_node_read_unlock(n);
1974 		if (found_node)
1975 			break;
1976 	}
1977 	rcu_read_unlock();
1978 
1979 	return found_node;
1980 }
1981 
1982 int tipc_nl_node_set_link(struct sk_buff *skb, struct genl_info *info)
1983 {
1984 	int err;
1985 	int res = 0;
1986 	int bearer_id;
1987 	char *name;
1988 	struct tipc_link *link;
1989 	struct tipc_node *node;
1990 	struct sk_buff_head xmitq;
1991 	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1992 	struct net *net = sock_net(skb->sk);
1993 
1994 	__skb_queue_head_init(&xmitq);
1995 
1996 	if (!info->attrs[TIPC_NLA_LINK])
1997 		return -EINVAL;
1998 
1999 	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2000 			       info->attrs[TIPC_NLA_LINK],
2001 			       tipc_nl_link_policy, info->extack);
2002 	if (err)
2003 		return err;
2004 
2005 	if (!attrs[TIPC_NLA_LINK_NAME])
2006 		return -EINVAL;
2007 
2008 	name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2009 
2010 	if (strcmp(name, tipc_bclink_name) == 0)
2011 		return tipc_nl_bc_link_set(net, attrs);
2012 
2013 	node = tipc_node_find_by_name(net, name, &bearer_id);
2014 	if (!node)
2015 		return -EINVAL;
2016 
2017 	tipc_node_read_lock(node);
2018 
2019 	link = node->links[bearer_id].link;
2020 	if (!link) {
2021 		res = -EINVAL;
2022 		goto out;
2023 	}
2024 
2025 	if (attrs[TIPC_NLA_LINK_PROP]) {
2026 		struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
2027 
2028 		err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
2029 					      props);
2030 		if (err) {
2031 			res = err;
2032 			goto out;
2033 		}
2034 
2035 		if (props[TIPC_NLA_PROP_TOL]) {
2036 			u32 tol;
2037 
2038 			tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
2039 			tipc_link_set_tolerance(link, tol, &xmitq);
2040 		}
2041 		if (props[TIPC_NLA_PROP_PRIO]) {
2042 			u32 prio;
2043 
2044 			prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
2045 			tipc_link_set_prio(link, prio, &xmitq);
2046 		}
2047 		if (props[TIPC_NLA_PROP_WIN]) {
2048 			u32 win;
2049 
2050 			win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
2051 			tipc_link_set_queue_limits(link, win);
2052 		}
2053 	}
2054 
2055 out:
2056 	tipc_node_read_unlock(node);
2057 	tipc_bearer_xmit(net, bearer_id, &xmitq, &node->links[bearer_id].maddr);
2058 	return res;
2059 }
2060 
2061 int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info)
2062 {
2063 	struct net *net = genl_info_net(info);
2064 	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
2065 	struct tipc_nl_msg msg;
2066 	char *name;
2067 	int err;
2068 
2069 	msg.portid = info->snd_portid;
2070 	msg.seq = info->snd_seq;
2071 
2072 	if (!info->attrs[TIPC_NLA_LINK])
2073 		return -EINVAL;
2074 
2075 	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2076 			       info->attrs[TIPC_NLA_LINK],
2077 			       tipc_nl_link_policy, info->extack);
2078 	if (err)
2079 		return err;
2080 
2081 	if (!attrs[TIPC_NLA_LINK_NAME])
2082 		return -EINVAL;
2083 
2084 	name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2085 
2086 	msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
2087 	if (!msg.skb)
2088 		return -ENOMEM;
2089 
2090 	if (strcmp(name, tipc_bclink_name) == 0) {
2091 		err = tipc_nl_add_bc_link(net, &msg);
2092 		if (err)
2093 			goto err_free;
2094 	} else {
2095 		int bearer_id;
2096 		struct tipc_node *node;
2097 		struct tipc_link *link;
2098 
2099 		node = tipc_node_find_by_name(net, name, &bearer_id);
2100 		if (!node) {
2101 			err = -EINVAL;
2102 			goto err_free;
2103 		}
2104 
2105 		tipc_node_read_lock(node);
2106 		link = node->links[bearer_id].link;
2107 		if (!link) {
2108 			tipc_node_read_unlock(node);
2109 			err = -EINVAL;
2110 			goto err_free;
2111 		}
2112 
2113 		err = __tipc_nl_add_link(net, &msg, link, 0);
2114 		tipc_node_read_unlock(node);
2115 		if (err)
2116 			goto err_free;
2117 	}
2118 
2119 	return genlmsg_reply(msg.skb, info);
2120 
2121 err_free:
2122 	nlmsg_free(msg.skb);
2123 	return err;
2124 }
2125 
2126 int tipc_nl_node_reset_link_stats(struct sk_buff *skb, struct genl_info *info)
2127 {
2128 	int err;
2129 	char *link_name;
2130 	unsigned int bearer_id;
2131 	struct tipc_link *link;
2132 	struct tipc_node *node;
2133 	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
2134 	struct net *net = sock_net(skb->sk);
2135 	struct tipc_link_entry *le;
2136 
2137 	if (!info->attrs[TIPC_NLA_LINK])
2138 		return -EINVAL;
2139 
2140 	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
2141 			       info->attrs[TIPC_NLA_LINK],
2142 			       tipc_nl_link_policy, info->extack);
2143 	if (err)
2144 		return err;
2145 
2146 	if (!attrs[TIPC_NLA_LINK_NAME])
2147 		return -EINVAL;
2148 
2149 	link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
2150 
2151 	if (strcmp(link_name, tipc_bclink_name) == 0) {
2152 		err = tipc_bclink_reset_stats(net);
2153 		if (err)
2154 			return err;
2155 		return 0;
2156 	}
2157 
2158 	node = tipc_node_find_by_name(net, link_name, &bearer_id);
2159 	if (!node)
2160 		return -EINVAL;
2161 
2162 	le = &node->links[bearer_id];
2163 	tipc_node_read_lock(node);
2164 	spin_lock_bh(&le->lock);
2165 	link = node->links[bearer_id].link;
2166 	if (!link) {
2167 		spin_unlock_bh(&le->lock);
2168 		tipc_node_read_unlock(node);
2169 		return -EINVAL;
2170 	}
2171 	tipc_link_reset_stats(link);
2172 	spin_unlock_bh(&le->lock);
2173 	tipc_node_read_unlock(node);
2174 	return 0;
2175 }
2176 
2177 /* Caller should hold node lock  */
2178 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
2179 				    struct tipc_node *node, u32 *prev_link)
2180 {
2181 	u32 i;
2182 	int err;
2183 
2184 	for (i = *prev_link; i < MAX_BEARERS; i++) {
2185 		*prev_link = i;
2186 
2187 		if (!node->links[i].link)
2188 			continue;
2189 
2190 		err = __tipc_nl_add_link(net, msg,
2191 					 node->links[i].link, NLM_F_MULTI);
2192 		if (err)
2193 			return err;
2194 	}
2195 	*prev_link = 0;
2196 
2197 	return 0;
2198 }
2199 
2200 int tipc_nl_node_dump_link(struct sk_buff *skb, struct netlink_callback *cb)
2201 {
2202 	struct net *net = sock_net(skb->sk);
2203 	struct tipc_net *tn = net_generic(net, tipc_net_id);
2204 	struct tipc_node *node;
2205 	struct tipc_nl_msg msg;
2206 	u32 prev_node = cb->args[0];
2207 	u32 prev_link = cb->args[1];
2208 	int done = cb->args[2];
2209 	int err;
2210 
2211 	if (done)
2212 		return 0;
2213 
2214 	msg.skb = skb;
2215 	msg.portid = NETLINK_CB(cb->skb).portid;
2216 	msg.seq = cb->nlh->nlmsg_seq;
2217 
2218 	rcu_read_lock();
2219 	if (prev_node) {
2220 		node = tipc_node_find(net, prev_node);
2221 		if (!node) {
2222 			/* We never set seq or call nl_dump_check_consistent()
2223 			 * this means that setting prev_seq here will cause the
2224 			 * consistence check to fail in the netlink callback
2225 			 * handler. Resulting in the last NLMSG_DONE message
2226 			 * having the NLM_F_DUMP_INTR flag set.
2227 			 */
2228 			cb->prev_seq = 1;
2229 			goto out;
2230 		}
2231 		tipc_node_put(node);
2232 
2233 		list_for_each_entry_continue_rcu(node, &tn->node_list,
2234 						 list) {
2235 			tipc_node_read_lock(node);
2236 			err = __tipc_nl_add_node_links(net, &msg, node,
2237 						       &prev_link);
2238 			tipc_node_read_unlock(node);
2239 			if (err)
2240 				goto out;
2241 
2242 			prev_node = node->addr;
2243 		}
2244 	} else {
2245 		err = tipc_nl_add_bc_link(net, &msg);
2246 		if (err)
2247 			goto out;
2248 
2249 		list_for_each_entry_rcu(node, &tn->node_list, list) {
2250 			tipc_node_read_lock(node);
2251 			err = __tipc_nl_add_node_links(net, &msg, node,
2252 						       &prev_link);
2253 			tipc_node_read_unlock(node);
2254 			if (err)
2255 				goto out;
2256 
2257 			prev_node = node->addr;
2258 		}
2259 	}
2260 	done = 1;
2261 out:
2262 	rcu_read_unlock();
2263 
2264 	cb->args[0] = prev_node;
2265 	cb->args[1] = prev_link;
2266 	cb->args[2] = done;
2267 
2268 	return skb->len;
2269 }
2270 
2271 int tipc_nl_node_set_monitor(struct sk_buff *skb, struct genl_info *info)
2272 {
2273 	struct nlattr *attrs[TIPC_NLA_MON_MAX + 1];
2274 	struct net *net = sock_net(skb->sk);
2275 	int err;
2276 
2277 	if (!info->attrs[TIPC_NLA_MON])
2278 		return -EINVAL;
2279 
2280 	err = nla_parse_nested(attrs, TIPC_NLA_MON_MAX,
2281 			       info->attrs[TIPC_NLA_MON],
2282 			       tipc_nl_monitor_policy, info->extack);
2283 	if (err)
2284 		return err;
2285 
2286 	if (attrs[TIPC_NLA_MON_ACTIVATION_THRESHOLD]) {
2287 		u32 val;
2288 
2289 		val = nla_get_u32(attrs[TIPC_NLA_MON_ACTIVATION_THRESHOLD]);
2290 		err = tipc_nl_monitor_set_threshold(net, val);
2291 		if (err)
2292 			return err;
2293 	}
2294 
2295 	return 0;
2296 }
2297 
2298 static int __tipc_nl_add_monitor_prop(struct net *net, struct tipc_nl_msg *msg)
2299 {
2300 	struct nlattr *attrs;
2301 	void *hdr;
2302 	u32 val;
2303 
2304 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2305 			  0, TIPC_NL_MON_GET);
2306 	if (!hdr)
2307 		return -EMSGSIZE;
2308 
2309 	attrs = nla_nest_start(msg->skb, TIPC_NLA_MON);
2310 	if (!attrs)
2311 		goto msg_full;
2312 
2313 	val = tipc_nl_monitor_get_threshold(net);
2314 
2315 	if (nla_put_u32(msg->skb, TIPC_NLA_MON_ACTIVATION_THRESHOLD, val))
2316 		goto attr_msg_full;
2317 
2318 	nla_nest_end(msg->skb, attrs);
2319 	genlmsg_end(msg->skb, hdr);
2320 
2321 	return 0;
2322 
2323 attr_msg_full:
2324 	nla_nest_cancel(msg->skb, attrs);
2325 msg_full:
2326 	genlmsg_cancel(msg->skb, hdr);
2327 
2328 	return -EMSGSIZE;
2329 }
2330 
2331 int tipc_nl_node_get_monitor(struct sk_buff *skb, struct genl_info *info)
2332 {
2333 	struct net *net = sock_net(skb->sk);
2334 	struct tipc_nl_msg msg;
2335 	int err;
2336 
2337 	msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
2338 	if (!msg.skb)
2339 		return -ENOMEM;
2340 	msg.portid = info->snd_portid;
2341 	msg.seq = info->snd_seq;
2342 
2343 	err = __tipc_nl_add_monitor_prop(net, &msg);
2344 	if (err) {
2345 		nlmsg_free(msg.skb);
2346 		return err;
2347 	}
2348 
2349 	return genlmsg_reply(msg.skb, info);
2350 }
2351 
2352 int tipc_nl_node_dump_monitor(struct sk_buff *skb, struct netlink_callback *cb)
2353 {
2354 	struct net *net = sock_net(skb->sk);
2355 	u32 prev_bearer = cb->args[0];
2356 	struct tipc_nl_msg msg;
2357 	int bearer_id;
2358 	int err;
2359 
2360 	if (prev_bearer == MAX_BEARERS)
2361 		return 0;
2362 
2363 	msg.skb = skb;
2364 	msg.portid = NETLINK_CB(cb->skb).portid;
2365 	msg.seq = cb->nlh->nlmsg_seq;
2366 
2367 	rtnl_lock();
2368 	for (bearer_id = prev_bearer; bearer_id < MAX_BEARERS; bearer_id++) {
2369 		err = __tipc_nl_add_monitor(net, &msg, bearer_id);
2370 		if (err)
2371 			break;
2372 	}
2373 	rtnl_unlock();
2374 	cb->args[0] = bearer_id;
2375 
2376 	return skb->len;
2377 }
2378 
2379 int tipc_nl_node_dump_monitor_peer(struct sk_buff *skb,
2380 				   struct netlink_callback *cb)
2381 {
2382 	struct net *net = sock_net(skb->sk);
2383 	u32 prev_node = cb->args[1];
2384 	u32 bearer_id = cb->args[2];
2385 	int done = cb->args[0];
2386 	struct tipc_nl_msg msg;
2387 	int err;
2388 
2389 	if (!prev_node) {
2390 		struct nlattr **attrs;
2391 		struct nlattr *mon[TIPC_NLA_MON_MAX + 1];
2392 
2393 		err = tipc_nlmsg_parse(cb->nlh, &attrs);
2394 		if (err)
2395 			return err;
2396 
2397 		if (!attrs[TIPC_NLA_MON])
2398 			return -EINVAL;
2399 
2400 		err = nla_parse_nested(mon, TIPC_NLA_MON_MAX,
2401 				       attrs[TIPC_NLA_MON],
2402 				       tipc_nl_monitor_policy, NULL);
2403 		if (err)
2404 			return err;
2405 
2406 		if (!mon[TIPC_NLA_MON_REF])
2407 			return -EINVAL;
2408 
2409 		bearer_id = nla_get_u32(mon[TIPC_NLA_MON_REF]);
2410 
2411 		if (bearer_id >= MAX_BEARERS)
2412 			return -EINVAL;
2413 	}
2414 
2415 	if (done)
2416 		return 0;
2417 
2418 	msg.skb = skb;
2419 	msg.portid = NETLINK_CB(cb->skb).portid;
2420 	msg.seq = cb->nlh->nlmsg_seq;
2421 
2422 	rtnl_lock();
2423 	err = tipc_nl_add_monitor_peer(net, &msg, bearer_id, &prev_node);
2424 	if (!err)
2425 		done = 1;
2426 
2427 	rtnl_unlock();
2428 	cb->args[0] = done;
2429 	cb->args[1] = prev_node;
2430 	cb->args[2] = bearer_id;
2431 
2432 	return skb->len;
2433 }
2434