xref: /linux/net/tipc/node.c (revision f3a8b6645dc2e60d11f20c1c23afd964ff4e55ae)
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 
49 /* Flags used to take different actions according to flag type
50  * TIPC_NOTIFY_NODE_DOWN: notify node is down
51  * TIPC_NOTIFY_NODE_UP: notify node is up
52  * TIPC_DISTRIBUTE_NAME: publish or withdraw link state name type
53  */
54 enum {
55 	TIPC_NOTIFY_NODE_DOWN		= (1 << 3),
56 	TIPC_NOTIFY_NODE_UP		= (1 << 4),
57 	TIPC_NOTIFY_LINK_UP		= (1 << 6),
58 	TIPC_NOTIFY_LINK_DOWN		= (1 << 7)
59 };
60 
61 struct tipc_link_entry {
62 	struct tipc_link *link;
63 	spinlock_t lock; /* per link */
64 	u32 mtu;
65 	struct sk_buff_head inputq;
66 	struct tipc_media_addr maddr;
67 };
68 
69 struct tipc_bclink_entry {
70 	struct tipc_link *link;
71 	struct sk_buff_head inputq1;
72 	struct sk_buff_head arrvq;
73 	struct sk_buff_head inputq2;
74 	struct sk_buff_head namedq;
75 };
76 
77 /**
78  * struct tipc_node - TIPC node structure
79  * @addr: network address of node
80  * @ref: reference counter to node object
81  * @lock: rwlock governing access to structure
82  * @net: the applicable net namespace
83  * @hash: links to adjacent nodes in unsorted hash chain
84  * @inputq: pointer to input queue containing messages for msg event
85  * @namedq: pointer to name table input queue with name table messages
86  * @active_links: bearer ids of active links, used as index into links[] array
87  * @links: array containing references to all links to node
88  * @action_flags: bit mask of different types of node actions
89  * @state: connectivity state vs peer node
90  * @sync_point: sequence number where synch/failover is finished
91  * @list: links to adjacent nodes in sorted list of cluster's nodes
92  * @working_links: number of working links to node (both active and standby)
93  * @link_cnt: number of links to node
94  * @capabilities: bitmap, indicating peer node's functional capabilities
95  * @signature: node instance identifier
96  * @link_id: local and remote bearer ids of changing link, if any
97  * @publ_list: list of publications
98  * @rcu: rcu struct for tipc_node
99  */
100 struct tipc_node {
101 	u32 addr;
102 	struct kref kref;
103 	rwlock_t lock;
104 	struct net *net;
105 	struct hlist_node hash;
106 	int active_links[2];
107 	struct tipc_link_entry links[MAX_BEARERS];
108 	struct tipc_bclink_entry bc_entry;
109 	int action_flags;
110 	struct list_head list;
111 	int state;
112 	u16 sync_point;
113 	int link_cnt;
114 	u16 working_links;
115 	u16 capabilities;
116 	u32 signature;
117 	u32 link_id;
118 	struct list_head publ_list;
119 	struct list_head conn_sks;
120 	unsigned long keepalive_intv;
121 	struct timer_list timer;
122 	struct rcu_head rcu;
123 };
124 
125 /* Node FSM states and events:
126  */
127 enum {
128 	SELF_DOWN_PEER_DOWN    = 0xdd,
129 	SELF_UP_PEER_UP        = 0xaa,
130 	SELF_DOWN_PEER_LEAVING = 0xd1,
131 	SELF_UP_PEER_COMING    = 0xac,
132 	SELF_COMING_PEER_UP    = 0xca,
133 	SELF_LEAVING_PEER_DOWN = 0x1d,
134 	NODE_FAILINGOVER       = 0xf0,
135 	NODE_SYNCHING          = 0xcc
136 };
137 
138 enum {
139 	SELF_ESTABL_CONTACT_EVT = 0xece,
140 	SELF_LOST_CONTACT_EVT   = 0x1ce,
141 	PEER_ESTABL_CONTACT_EVT = 0x9ece,
142 	PEER_LOST_CONTACT_EVT   = 0x91ce,
143 	NODE_FAILOVER_BEGIN_EVT = 0xfbe,
144 	NODE_FAILOVER_END_EVT   = 0xfee,
145 	NODE_SYNCH_BEGIN_EVT    = 0xcbe,
146 	NODE_SYNCH_END_EVT      = 0xcee
147 };
148 
149 static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
150 				  struct sk_buff_head *xmitq,
151 				  struct tipc_media_addr **maddr);
152 static void tipc_node_link_down(struct tipc_node *n, int bearer_id,
153 				bool delete);
154 static void node_lost_contact(struct tipc_node *n, struct sk_buff_head *inputq);
155 static void tipc_node_delete(struct tipc_node *node);
156 static void tipc_node_timeout(unsigned long data);
157 static void tipc_node_fsm_evt(struct tipc_node *n, int evt);
158 static struct tipc_node *tipc_node_find(struct net *net, u32 addr);
159 static void tipc_node_put(struct tipc_node *node);
160 static bool tipc_node_is_up(struct tipc_node *n);
161 
162 struct tipc_sock_conn {
163 	u32 port;
164 	u32 peer_port;
165 	u32 peer_node;
166 	struct list_head list;
167 };
168 
169 static struct tipc_link *node_active_link(struct tipc_node *n, int sel)
170 {
171 	int bearer_id = n->active_links[sel & 1];
172 
173 	if (unlikely(bearer_id == INVALID_BEARER_ID))
174 		return NULL;
175 
176 	return n->links[bearer_id].link;
177 }
178 
179 int tipc_node_get_mtu(struct net *net, u32 addr, u32 sel)
180 {
181 	struct tipc_node *n;
182 	int bearer_id;
183 	unsigned int mtu = MAX_MSG_SIZE;
184 
185 	n = tipc_node_find(net, addr);
186 	if (unlikely(!n))
187 		return mtu;
188 
189 	bearer_id = n->active_links[sel & 1];
190 	if (likely(bearer_id != INVALID_BEARER_ID))
191 		mtu = n->links[bearer_id].mtu;
192 	tipc_node_put(n);
193 	return mtu;
194 }
195 
196 u16 tipc_node_get_capabilities(struct net *net, u32 addr)
197 {
198 	struct tipc_node *n;
199 	u16 caps;
200 
201 	n = tipc_node_find(net, addr);
202 	if (unlikely(!n))
203 		return TIPC_NODE_CAPABILITIES;
204 	caps = n->capabilities;
205 	tipc_node_put(n);
206 	return caps;
207 }
208 
209 static void tipc_node_kref_release(struct kref *kref)
210 {
211 	struct tipc_node *n = container_of(kref, struct tipc_node, kref);
212 
213 	kfree(n->bc_entry.link);
214 	kfree_rcu(n, rcu);
215 }
216 
217 static void tipc_node_put(struct tipc_node *node)
218 {
219 	kref_put(&node->kref, tipc_node_kref_release);
220 }
221 
222 static void tipc_node_get(struct tipc_node *node)
223 {
224 	kref_get(&node->kref);
225 }
226 
227 /*
228  * tipc_node_find - locate specified node object, if it exists
229  */
230 static struct tipc_node *tipc_node_find(struct net *net, u32 addr)
231 {
232 	struct tipc_net *tn = tipc_net(net);
233 	struct tipc_node *node;
234 	unsigned int thash = tipc_hashfn(addr);
235 
236 	if (unlikely(!in_own_cluster_exact(net, addr)))
237 		return NULL;
238 
239 	rcu_read_lock();
240 	hlist_for_each_entry_rcu(node, &tn->node_htable[thash], hash) {
241 		if (node->addr != addr)
242 			continue;
243 		if (!kref_get_unless_zero(&node->kref))
244 			node = NULL;
245 		break;
246 	}
247 	rcu_read_unlock();
248 	return node;
249 }
250 
251 static void tipc_node_read_lock(struct tipc_node *n)
252 {
253 	read_lock_bh(&n->lock);
254 }
255 
256 static void tipc_node_read_unlock(struct tipc_node *n)
257 {
258 	read_unlock_bh(&n->lock);
259 }
260 
261 static void tipc_node_write_lock(struct tipc_node *n)
262 {
263 	write_lock_bh(&n->lock);
264 }
265 
266 static void tipc_node_write_unlock(struct tipc_node *n)
267 {
268 	struct net *net = n->net;
269 	u32 addr = 0;
270 	u32 flags = n->action_flags;
271 	u32 link_id = 0;
272 	u32 bearer_id;
273 	struct list_head *publ_list;
274 
275 	if (likely(!flags)) {
276 		write_unlock_bh(&n->lock);
277 		return;
278 	}
279 
280 	addr = n->addr;
281 	link_id = n->link_id;
282 	bearer_id = link_id & 0xffff;
283 	publ_list = &n->publ_list;
284 
285 	n->action_flags &= ~(TIPC_NOTIFY_NODE_DOWN | TIPC_NOTIFY_NODE_UP |
286 			     TIPC_NOTIFY_LINK_DOWN | TIPC_NOTIFY_LINK_UP);
287 
288 	write_unlock_bh(&n->lock);
289 
290 	if (flags & TIPC_NOTIFY_NODE_DOWN)
291 		tipc_publ_notify(net, publ_list, addr);
292 
293 	if (flags & TIPC_NOTIFY_NODE_UP)
294 		tipc_named_node_up(net, addr);
295 
296 	if (flags & TIPC_NOTIFY_LINK_UP) {
297 		tipc_mon_peer_up(net, addr, bearer_id);
298 		tipc_nametbl_publish(net, TIPC_LINK_STATE, addr, addr,
299 				     TIPC_NODE_SCOPE, link_id, addr);
300 	}
301 	if (flags & TIPC_NOTIFY_LINK_DOWN) {
302 		tipc_mon_peer_down(net, addr, bearer_id);
303 		tipc_nametbl_withdraw(net, TIPC_LINK_STATE, addr,
304 				      link_id, addr);
305 	}
306 }
307 
308 struct tipc_node *tipc_node_create(struct net *net, u32 addr, u16 capabilities)
309 {
310 	struct tipc_net *tn = net_generic(net, tipc_net_id);
311 	struct tipc_node *n, *temp_node;
312 	int i;
313 
314 	spin_lock_bh(&tn->node_list_lock);
315 	n = tipc_node_find(net, addr);
316 	if (n) {
317 		/* Same node may come back with new capabilities */
318 		n->capabilities = capabilities;
319 		goto exit;
320 	}
321 	n = kzalloc(sizeof(*n), GFP_ATOMIC);
322 	if (!n) {
323 		pr_warn("Node creation failed, no memory\n");
324 		goto exit;
325 	}
326 	n->addr = addr;
327 	n->net = net;
328 	n->capabilities = capabilities;
329 	kref_init(&n->kref);
330 	rwlock_init(&n->lock);
331 	INIT_HLIST_NODE(&n->hash);
332 	INIT_LIST_HEAD(&n->list);
333 	INIT_LIST_HEAD(&n->publ_list);
334 	INIT_LIST_HEAD(&n->conn_sks);
335 	skb_queue_head_init(&n->bc_entry.namedq);
336 	skb_queue_head_init(&n->bc_entry.inputq1);
337 	__skb_queue_head_init(&n->bc_entry.arrvq);
338 	skb_queue_head_init(&n->bc_entry.inputq2);
339 	for (i = 0; i < MAX_BEARERS; i++)
340 		spin_lock_init(&n->links[i].lock);
341 	n->state = SELF_DOWN_PEER_LEAVING;
342 	n->signature = INVALID_NODE_SIG;
343 	n->active_links[0] = INVALID_BEARER_ID;
344 	n->active_links[1] = INVALID_BEARER_ID;
345 	if (!tipc_link_bc_create(net, tipc_own_addr(net), n->addr,
346 				 U16_MAX,
347 				 tipc_link_window(tipc_bc_sndlink(net)),
348 				 n->capabilities,
349 				 &n->bc_entry.inputq1,
350 				 &n->bc_entry.namedq,
351 				 tipc_bc_sndlink(net),
352 				 &n->bc_entry.link)) {
353 		pr_warn("Broadcast rcv link creation failed, no memory\n");
354 		kfree(n);
355 		n = NULL;
356 		goto exit;
357 	}
358 	tipc_node_get(n);
359 	setup_timer(&n->timer, tipc_node_timeout, (unsigned long)n);
360 	n->keepalive_intv = U32_MAX;
361 	hlist_add_head_rcu(&n->hash, &tn->node_htable[tipc_hashfn(addr)]);
362 	list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
363 		if (n->addr < temp_node->addr)
364 			break;
365 	}
366 	list_add_tail_rcu(&n->list, &temp_node->list);
367 exit:
368 	spin_unlock_bh(&tn->node_list_lock);
369 	return n;
370 }
371 
372 static void tipc_node_calculate_timer(struct tipc_node *n, struct tipc_link *l)
373 {
374 	unsigned long tol = tipc_link_tolerance(l);
375 	unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
376 
377 	/* Link with lowest tolerance determines timer interval */
378 	if (intv < n->keepalive_intv)
379 		n->keepalive_intv = intv;
380 
381 	/* Ensure link's abort limit corresponds to current tolerance */
382 	tipc_link_set_abort_limit(l, tol / n->keepalive_intv);
383 }
384 
385 static void tipc_node_delete(struct tipc_node *node)
386 {
387 	list_del_rcu(&node->list);
388 	hlist_del_rcu(&node->hash);
389 	tipc_node_put(node);
390 
391 	del_timer_sync(&node->timer);
392 	tipc_node_put(node);
393 }
394 
395 void tipc_node_stop(struct net *net)
396 {
397 	struct tipc_net *tn = tipc_net(net);
398 	struct tipc_node *node, *t_node;
399 
400 	spin_lock_bh(&tn->node_list_lock);
401 	list_for_each_entry_safe(node, t_node, &tn->node_list, list)
402 		tipc_node_delete(node);
403 	spin_unlock_bh(&tn->node_list_lock);
404 }
405 
406 void tipc_node_subscribe(struct net *net, struct list_head *subscr, u32 addr)
407 {
408 	struct tipc_node *n;
409 
410 	if (in_own_node(net, addr))
411 		return;
412 
413 	n = tipc_node_find(net, addr);
414 	if (!n) {
415 		pr_warn("Node subscribe rejected, unknown node 0x%x\n", addr);
416 		return;
417 	}
418 	tipc_node_write_lock(n);
419 	list_add_tail(subscr, &n->publ_list);
420 	tipc_node_write_unlock(n);
421 	tipc_node_put(n);
422 }
423 
424 void tipc_node_unsubscribe(struct net *net, struct list_head *subscr, u32 addr)
425 {
426 	struct tipc_node *n;
427 
428 	if (in_own_node(net, addr))
429 		return;
430 
431 	n = tipc_node_find(net, addr);
432 	if (!n) {
433 		pr_warn("Node unsubscribe rejected, unknown node 0x%x\n", addr);
434 		return;
435 	}
436 	tipc_node_write_lock(n);
437 	list_del_init(subscr);
438 	tipc_node_write_unlock(n);
439 	tipc_node_put(n);
440 }
441 
442 int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port)
443 {
444 	struct tipc_node *node;
445 	struct tipc_sock_conn *conn;
446 	int err = 0;
447 
448 	if (in_own_node(net, dnode))
449 		return 0;
450 
451 	node = tipc_node_find(net, dnode);
452 	if (!node) {
453 		pr_warn("Connecting sock to node 0x%x failed\n", dnode);
454 		return -EHOSTUNREACH;
455 	}
456 	conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
457 	if (!conn) {
458 		err = -EHOSTUNREACH;
459 		goto exit;
460 	}
461 	conn->peer_node = dnode;
462 	conn->port = port;
463 	conn->peer_port = peer_port;
464 
465 	tipc_node_write_lock(node);
466 	list_add_tail(&conn->list, &node->conn_sks);
467 	tipc_node_write_unlock(node);
468 exit:
469 	tipc_node_put(node);
470 	return err;
471 }
472 
473 void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port)
474 {
475 	struct tipc_node *node;
476 	struct tipc_sock_conn *conn, *safe;
477 
478 	if (in_own_node(net, dnode))
479 		return;
480 
481 	node = tipc_node_find(net, dnode);
482 	if (!node)
483 		return;
484 
485 	tipc_node_write_lock(node);
486 	list_for_each_entry_safe(conn, safe, &node->conn_sks, list) {
487 		if (port != conn->port)
488 			continue;
489 		list_del(&conn->list);
490 		kfree(conn);
491 	}
492 	tipc_node_write_unlock(node);
493 	tipc_node_put(node);
494 }
495 
496 /* tipc_node_timeout - handle expiration of node timer
497  */
498 static void tipc_node_timeout(unsigned long data)
499 {
500 	struct tipc_node *n = (struct tipc_node *)data;
501 	struct tipc_link_entry *le;
502 	struct sk_buff_head xmitq;
503 	int bearer_id;
504 	int rc = 0;
505 
506 	__skb_queue_head_init(&xmitq);
507 
508 	for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
509 		tipc_node_read_lock(n);
510 		le = &n->links[bearer_id];
511 		spin_lock_bh(&le->lock);
512 		if (le->link) {
513 			/* Link tolerance may change asynchronously: */
514 			tipc_node_calculate_timer(n, le->link);
515 			rc = tipc_link_timeout(le->link, &xmitq);
516 		}
517 		spin_unlock_bh(&le->lock);
518 		tipc_node_read_unlock(n);
519 		tipc_bearer_xmit(n->net, bearer_id, &xmitq, &le->maddr);
520 		if (rc & TIPC_LINK_DOWN_EVT)
521 			tipc_node_link_down(n, bearer_id, false);
522 	}
523 	mod_timer(&n->timer, jiffies + msecs_to_jiffies(n->keepalive_intv));
524 }
525 
526 /**
527  * __tipc_node_link_up - handle addition of link
528  * Node lock must be held by caller
529  * Link becomes active (alone or shared) or standby, depending on its priority.
530  */
531 static void __tipc_node_link_up(struct tipc_node *n, int bearer_id,
532 				struct sk_buff_head *xmitq)
533 {
534 	int *slot0 = &n->active_links[0];
535 	int *slot1 = &n->active_links[1];
536 	struct tipc_link *ol = node_active_link(n, 0);
537 	struct tipc_link *nl = n->links[bearer_id].link;
538 
539 	if (!nl || tipc_link_is_up(nl))
540 		return;
541 
542 	tipc_link_fsm_evt(nl, LINK_ESTABLISH_EVT);
543 	if (!tipc_link_is_up(nl))
544 		return;
545 
546 	n->working_links++;
547 	n->action_flags |= TIPC_NOTIFY_LINK_UP;
548 	n->link_id = tipc_link_id(nl);
549 
550 	/* Leave room for tunnel header when returning 'mtu' to users: */
551 	n->links[bearer_id].mtu = tipc_link_mtu(nl) - INT_H_SIZE;
552 
553 	tipc_bearer_add_dest(n->net, bearer_id, n->addr);
554 	tipc_bcast_inc_bearer_dst_cnt(n->net, bearer_id);
555 
556 	pr_debug("Established link <%s> on network plane %c\n",
557 		 tipc_link_name(nl), tipc_link_plane(nl));
558 
559 	/* Ensure that a STATE message goes first */
560 	tipc_link_build_state_msg(nl, xmitq);
561 
562 	/* First link? => give it both slots */
563 	if (!ol) {
564 		*slot0 = bearer_id;
565 		*slot1 = bearer_id;
566 		tipc_node_fsm_evt(n, SELF_ESTABL_CONTACT_EVT);
567 		n->action_flags |= TIPC_NOTIFY_NODE_UP;
568 		tipc_link_set_active(nl, true);
569 		tipc_bcast_add_peer(n->net, nl, xmitq);
570 		return;
571 	}
572 
573 	/* Second link => redistribute slots */
574 	if (tipc_link_prio(nl) > tipc_link_prio(ol)) {
575 		pr_debug("Old link <%s> becomes standby\n", tipc_link_name(ol));
576 		*slot0 = bearer_id;
577 		*slot1 = bearer_id;
578 		tipc_link_set_active(nl, true);
579 		tipc_link_set_active(ol, false);
580 	} else if (tipc_link_prio(nl) == tipc_link_prio(ol)) {
581 		tipc_link_set_active(nl, true);
582 		*slot1 = bearer_id;
583 	} else {
584 		pr_debug("New link <%s> is standby\n", tipc_link_name(nl));
585 	}
586 
587 	/* Prepare synchronization with first link */
588 	tipc_link_tnl_prepare(ol, nl, SYNCH_MSG, xmitq);
589 }
590 
591 /**
592  * tipc_node_link_up - handle addition of link
593  *
594  * Link becomes active (alone or shared) or standby, depending on its priority.
595  */
596 static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
597 			      struct sk_buff_head *xmitq)
598 {
599 	struct tipc_media_addr *maddr;
600 
601 	tipc_node_write_lock(n);
602 	__tipc_node_link_up(n, bearer_id, xmitq);
603 	maddr = &n->links[bearer_id].maddr;
604 	tipc_bearer_xmit(n->net, bearer_id, xmitq, maddr);
605 	tipc_node_write_unlock(n);
606 }
607 
608 /**
609  * __tipc_node_link_down - handle loss of link
610  */
611 static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
612 				  struct sk_buff_head *xmitq,
613 				  struct tipc_media_addr **maddr)
614 {
615 	struct tipc_link_entry *le = &n->links[*bearer_id];
616 	int *slot0 = &n->active_links[0];
617 	int *slot1 = &n->active_links[1];
618 	int i, highest = 0, prio;
619 	struct tipc_link *l, *_l, *tnl;
620 
621 	l = n->links[*bearer_id].link;
622 	if (!l || tipc_link_is_reset(l))
623 		return;
624 
625 	n->working_links--;
626 	n->action_flags |= TIPC_NOTIFY_LINK_DOWN;
627 	n->link_id = tipc_link_id(l);
628 
629 	tipc_bearer_remove_dest(n->net, *bearer_id, n->addr);
630 
631 	pr_debug("Lost link <%s> on network plane %c\n",
632 		 tipc_link_name(l), tipc_link_plane(l));
633 
634 	/* Select new active link if any available */
635 	*slot0 = INVALID_BEARER_ID;
636 	*slot1 = INVALID_BEARER_ID;
637 	for (i = 0; i < MAX_BEARERS; i++) {
638 		_l = n->links[i].link;
639 		if (!_l || !tipc_link_is_up(_l))
640 			continue;
641 		if (_l == l)
642 			continue;
643 		prio = tipc_link_prio(_l);
644 		if (prio < highest)
645 			continue;
646 		if (prio > highest) {
647 			highest = prio;
648 			*slot0 = i;
649 			*slot1 = i;
650 			continue;
651 		}
652 		*slot1 = i;
653 	}
654 
655 	if (!tipc_node_is_up(n)) {
656 		if (tipc_link_peer_is_down(l))
657 			tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
658 		tipc_node_fsm_evt(n, SELF_LOST_CONTACT_EVT);
659 		tipc_link_fsm_evt(l, LINK_RESET_EVT);
660 		tipc_link_reset(l);
661 		tipc_link_build_reset_msg(l, xmitq);
662 		*maddr = &n->links[*bearer_id].maddr;
663 		node_lost_contact(n, &le->inputq);
664 		tipc_bcast_dec_bearer_dst_cnt(n->net, *bearer_id);
665 		return;
666 	}
667 	tipc_bcast_dec_bearer_dst_cnt(n->net, *bearer_id);
668 
669 	/* There is still a working link => initiate failover */
670 	*bearer_id = n->active_links[0];
671 	tnl = n->links[*bearer_id].link;
672 	tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
673 	tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
674 	n->sync_point = tipc_link_rcv_nxt(tnl) + (U16_MAX / 2 - 1);
675 	tipc_link_tnl_prepare(l, tnl, FAILOVER_MSG, xmitq);
676 	tipc_link_reset(l);
677 	tipc_link_fsm_evt(l, LINK_RESET_EVT);
678 	tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
679 	tipc_node_fsm_evt(n, NODE_FAILOVER_BEGIN_EVT);
680 	*maddr = &n->links[*bearer_id].maddr;
681 }
682 
683 static void tipc_node_link_down(struct tipc_node *n, int bearer_id, bool delete)
684 {
685 	struct tipc_link_entry *le = &n->links[bearer_id];
686 	struct tipc_link *l = le->link;
687 	struct tipc_media_addr *maddr;
688 	struct sk_buff_head xmitq;
689 	int old_bearer_id = bearer_id;
690 
691 	if (!l)
692 		return;
693 
694 	__skb_queue_head_init(&xmitq);
695 
696 	tipc_node_write_lock(n);
697 	if (!tipc_link_is_establishing(l)) {
698 		__tipc_node_link_down(n, &bearer_id, &xmitq, &maddr);
699 		if (delete) {
700 			kfree(l);
701 			le->link = NULL;
702 			n->link_cnt--;
703 		}
704 	} else {
705 		/* Defuse pending tipc_node_link_up() */
706 		tipc_link_fsm_evt(l, LINK_RESET_EVT);
707 	}
708 	tipc_node_write_unlock(n);
709 	if (delete)
710 		tipc_mon_remove_peer(n->net, n->addr, old_bearer_id);
711 	tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
712 	tipc_sk_rcv(n->net, &le->inputq);
713 }
714 
715 static bool tipc_node_is_up(struct tipc_node *n)
716 {
717 	return n->active_links[0] != INVALID_BEARER_ID;
718 }
719 
720 void tipc_node_check_dest(struct net *net, u32 onode,
721 			  struct tipc_bearer *b,
722 			  u16 capabilities, u32 signature,
723 			  struct tipc_media_addr *maddr,
724 			  bool *respond, bool *dupl_addr)
725 {
726 	struct tipc_node *n;
727 	struct tipc_link *l;
728 	struct tipc_link_entry *le;
729 	bool addr_match = false;
730 	bool sign_match = false;
731 	bool link_up = false;
732 	bool accept_addr = false;
733 	bool reset = true;
734 	char *if_name;
735 	unsigned long intv;
736 
737 	*dupl_addr = false;
738 	*respond = false;
739 
740 	n = tipc_node_create(net, onode, capabilities);
741 	if (!n)
742 		return;
743 
744 	tipc_node_write_lock(n);
745 
746 	le = &n->links[b->identity];
747 
748 	/* Prepare to validate requesting node's signature and media address */
749 	l = le->link;
750 	link_up = l && tipc_link_is_up(l);
751 	addr_match = l && !memcmp(&le->maddr, maddr, sizeof(*maddr));
752 	sign_match = (signature == n->signature);
753 
754 	/* These three flags give us eight permutations: */
755 
756 	if (sign_match && addr_match && link_up) {
757 		/* All is fine. Do nothing. */
758 		reset = false;
759 	} else if (sign_match && addr_match && !link_up) {
760 		/* Respond. The link will come up in due time */
761 		*respond = true;
762 	} else if (sign_match && !addr_match && link_up) {
763 		/* Peer has changed i/f address without rebooting.
764 		 * If so, the link will reset soon, and the next
765 		 * discovery will be accepted. So we can ignore it.
766 		 * It may also be an cloned or malicious peer having
767 		 * chosen the same node address and signature as an
768 		 * existing one.
769 		 * Ignore requests until the link goes down, if ever.
770 		 */
771 		*dupl_addr = true;
772 	} else if (sign_match && !addr_match && !link_up) {
773 		/* Peer link has changed i/f address without rebooting.
774 		 * It may also be a cloned or malicious peer; we can't
775 		 * distinguish between the two.
776 		 * The signature is correct, so we must accept.
777 		 */
778 		accept_addr = true;
779 		*respond = true;
780 	} else if (!sign_match && addr_match && link_up) {
781 		/* Peer node rebooted. Two possibilities:
782 		 *  - Delayed re-discovery; this link endpoint has already
783 		 *    reset and re-established contact with the peer, before
784 		 *    receiving a discovery message from that node.
785 		 *    (The peer happened to receive one from this node first).
786 		 *  - The peer came back so fast that our side has not
787 		 *    discovered it yet. Probing from this side will soon
788 		 *    reset the link, since there can be no working link
789 		 *    endpoint at the peer end, and the link will re-establish.
790 		 *  Accept the signature, since it comes from a known peer.
791 		 */
792 		n->signature = signature;
793 	} else if (!sign_match && addr_match && !link_up) {
794 		/*  The peer node has rebooted.
795 		 *  Accept signature, since it is a known peer.
796 		 */
797 		n->signature = signature;
798 		*respond = true;
799 	} else if (!sign_match && !addr_match && link_up) {
800 		/* Peer rebooted with new address, or a new/duplicate peer.
801 		 * Ignore until the link goes down, if ever.
802 		 */
803 		*dupl_addr = true;
804 	} else if (!sign_match && !addr_match && !link_up) {
805 		/* Peer rebooted with new address, or it is a new peer.
806 		 * Accept signature and address.
807 		 */
808 		n->signature = signature;
809 		accept_addr = true;
810 		*respond = true;
811 	}
812 
813 	if (!accept_addr)
814 		goto exit;
815 
816 	/* Now create new link if not already existing */
817 	if (!l) {
818 		if (n->link_cnt == 2) {
819 			pr_warn("Cannot establish 3rd link to %x\n", n->addr);
820 			goto exit;
821 		}
822 		if_name = strchr(b->name, ':') + 1;
823 		if (!tipc_link_create(net, if_name, b->identity, b->tolerance,
824 				      b->net_plane, b->mtu, b->priority,
825 				      b->window, mod(tipc_net(net)->random),
826 				      tipc_own_addr(net), onode,
827 				      n->capabilities,
828 				      tipc_bc_sndlink(n->net), n->bc_entry.link,
829 				      &le->inputq,
830 				      &n->bc_entry.namedq, &l)) {
831 			*respond = false;
832 			goto exit;
833 		}
834 		tipc_link_reset(l);
835 		tipc_link_fsm_evt(l, LINK_RESET_EVT);
836 		if (n->state == NODE_FAILINGOVER)
837 			tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
838 		le->link = l;
839 		n->link_cnt++;
840 		tipc_node_calculate_timer(n, l);
841 		if (n->link_cnt == 1) {
842 			intv = jiffies + msecs_to_jiffies(n->keepalive_intv);
843 			if (!mod_timer(&n->timer, intv))
844 				tipc_node_get(n);
845 		}
846 	}
847 	memcpy(&le->maddr, maddr, sizeof(*maddr));
848 exit:
849 	tipc_node_write_unlock(n);
850 	if (reset && l && !tipc_link_is_reset(l))
851 		tipc_node_link_down(n, b->identity, false);
852 	tipc_node_put(n);
853 }
854 
855 void tipc_node_delete_links(struct net *net, int bearer_id)
856 {
857 	struct tipc_net *tn = net_generic(net, tipc_net_id);
858 	struct tipc_node *n;
859 
860 	rcu_read_lock();
861 	list_for_each_entry_rcu(n, &tn->node_list, list) {
862 		tipc_node_link_down(n, bearer_id, true);
863 	}
864 	rcu_read_unlock();
865 }
866 
867 static void tipc_node_reset_links(struct tipc_node *n)
868 {
869 	char addr_string[16];
870 	int i;
871 
872 	pr_warn("Resetting all links to %s\n",
873 		tipc_addr_string_fill(addr_string, n->addr));
874 
875 	for (i = 0; i < MAX_BEARERS; i++) {
876 		tipc_node_link_down(n, i, false);
877 	}
878 }
879 
880 /* tipc_node_fsm_evt - node finite state machine
881  * Determines when contact is allowed with peer node
882  */
883 static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
884 {
885 	int state = n->state;
886 
887 	switch (state) {
888 	case SELF_DOWN_PEER_DOWN:
889 		switch (evt) {
890 		case SELF_ESTABL_CONTACT_EVT:
891 			state = SELF_UP_PEER_COMING;
892 			break;
893 		case PEER_ESTABL_CONTACT_EVT:
894 			state = SELF_COMING_PEER_UP;
895 			break;
896 		case SELF_LOST_CONTACT_EVT:
897 		case PEER_LOST_CONTACT_EVT:
898 			break;
899 		case NODE_SYNCH_END_EVT:
900 		case NODE_SYNCH_BEGIN_EVT:
901 		case NODE_FAILOVER_BEGIN_EVT:
902 		case NODE_FAILOVER_END_EVT:
903 		default:
904 			goto illegal_evt;
905 		}
906 		break;
907 	case SELF_UP_PEER_UP:
908 		switch (evt) {
909 		case SELF_LOST_CONTACT_EVT:
910 			state = SELF_DOWN_PEER_LEAVING;
911 			break;
912 		case PEER_LOST_CONTACT_EVT:
913 			state = SELF_LEAVING_PEER_DOWN;
914 			break;
915 		case NODE_SYNCH_BEGIN_EVT:
916 			state = NODE_SYNCHING;
917 			break;
918 		case NODE_FAILOVER_BEGIN_EVT:
919 			state = NODE_FAILINGOVER;
920 			break;
921 		case SELF_ESTABL_CONTACT_EVT:
922 		case PEER_ESTABL_CONTACT_EVT:
923 		case NODE_SYNCH_END_EVT:
924 		case NODE_FAILOVER_END_EVT:
925 			break;
926 		default:
927 			goto illegal_evt;
928 		}
929 		break;
930 	case SELF_DOWN_PEER_LEAVING:
931 		switch (evt) {
932 		case PEER_LOST_CONTACT_EVT:
933 			state = SELF_DOWN_PEER_DOWN;
934 			break;
935 		case SELF_ESTABL_CONTACT_EVT:
936 		case PEER_ESTABL_CONTACT_EVT:
937 		case SELF_LOST_CONTACT_EVT:
938 			break;
939 		case NODE_SYNCH_END_EVT:
940 		case NODE_SYNCH_BEGIN_EVT:
941 		case NODE_FAILOVER_BEGIN_EVT:
942 		case NODE_FAILOVER_END_EVT:
943 		default:
944 			goto illegal_evt;
945 		}
946 		break;
947 	case SELF_UP_PEER_COMING:
948 		switch (evt) {
949 		case PEER_ESTABL_CONTACT_EVT:
950 			state = SELF_UP_PEER_UP;
951 			break;
952 		case SELF_LOST_CONTACT_EVT:
953 			state = SELF_DOWN_PEER_DOWN;
954 			break;
955 		case SELF_ESTABL_CONTACT_EVT:
956 		case PEER_LOST_CONTACT_EVT:
957 		case NODE_SYNCH_END_EVT:
958 		case NODE_FAILOVER_BEGIN_EVT:
959 			break;
960 		case NODE_SYNCH_BEGIN_EVT:
961 		case NODE_FAILOVER_END_EVT:
962 		default:
963 			goto illegal_evt;
964 		}
965 		break;
966 	case SELF_COMING_PEER_UP:
967 		switch (evt) {
968 		case SELF_ESTABL_CONTACT_EVT:
969 			state = SELF_UP_PEER_UP;
970 			break;
971 		case PEER_LOST_CONTACT_EVT:
972 			state = SELF_DOWN_PEER_DOWN;
973 			break;
974 		case SELF_LOST_CONTACT_EVT:
975 		case PEER_ESTABL_CONTACT_EVT:
976 			break;
977 		case NODE_SYNCH_END_EVT:
978 		case NODE_SYNCH_BEGIN_EVT:
979 		case NODE_FAILOVER_BEGIN_EVT:
980 		case NODE_FAILOVER_END_EVT:
981 		default:
982 			goto illegal_evt;
983 		}
984 		break;
985 	case SELF_LEAVING_PEER_DOWN:
986 		switch (evt) {
987 		case SELF_LOST_CONTACT_EVT:
988 			state = SELF_DOWN_PEER_DOWN;
989 			break;
990 		case SELF_ESTABL_CONTACT_EVT:
991 		case PEER_ESTABL_CONTACT_EVT:
992 		case PEER_LOST_CONTACT_EVT:
993 			break;
994 		case NODE_SYNCH_END_EVT:
995 		case NODE_SYNCH_BEGIN_EVT:
996 		case NODE_FAILOVER_BEGIN_EVT:
997 		case NODE_FAILOVER_END_EVT:
998 		default:
999 			goto illegal_evt;
1000 		}
1001 		break;
1002 	case NODE_FAILINGOVER:
1003 		switch (evt) {
1004 		case SELF_LOST_CONTACT_EVT:
1005 			state = SELF_DOWN_PEER_LEAVING;
1006 			break;
1007 		case PEER_LOST_CONTACT_EVT:
1008 			state = SELF_LEAVING_PEER_DOWN;
1009 			break;
1010 		case NODE_FAILOVER_END_EVT:
1011 			state = SELF_UP_PEER_UP;
1012 			break;
1013 		case NODE_FAILOVER_BEGIN_EVT:
1014 		case SELF_ESTABL_CONTACT_EVT:
1015 		case PEER_ESTABL_CONTACT_EVT:
1016 			break;
1017 		case NODE_SYNCH_BEGIN_EVT:
1018 		case NODE_SYNCH_END_EVT:
1019 		default:
1020 			goto illegal_evt;
1021 		}
1022 		break;
1023 	case NODE_SYNCHING:
1024 		switch (evt) {
1025 		case SELF_LOST_CONTACT_EVT:
1026 			state = SELF_DOWN_PEER_LEAVING;
1027 			break;
1028 		case PEER_LOST_CONTACT_EVT:
1029 			state = SELF_LEAVING_PEER_DOWN;
1030 			break;
1031 		case NODE_SYNCH_END_EVT:
1032 			state = SELF_UP_PEER_UP;
1033 			break;
1034 		case NODE_FAILOVER_BEGIN_EVT:
1035 			state = NODE_FAILINGOVER;
1036 			break;
1037 		case NODE_SYNCH_BEGIN_EVT:
1038 		case SELF_ESTABL_CONTACT_EVT:
1039 		case PEER_ESTABL_CONTACT_EVT:
1040 			break;
1041 		case NODE_FAILOVER_END_EVT:
1042 		default:
1043 			goto illegal_evt;
1044 		}
1045 		break;
1046 	default:
1047 		pr_err("Unknown node fsm state %x\n", state);
1048 		break;
1049 	}
1050 	n->state = state;
1051 	return;
1052 
1053 illegal_evt:
1054 	pr_err("Illegal node fsm evt %x in state %x\n", evt, state);
1055 }
1056 
1057 static void node_lost_contact(struct tipc_node *n,
1058 			      struct sk_buff_head *inputq)
1059 {
1060 	char addr_string[16];
1061 	struct tipc_sock_conn *conn, *safe;
1062 	struct tipc_link *l;
1063 	struct list_head *conns = &n->conn_sks;
1064 	struct sk_buff *skb;
1065 	uint i;
1066 
1067 	pr_debug("Lost contact with %s\n",
1068 		 tipc_addr_string_fill(addr_string, n->addr));
1069 
1070 	/* Clean up broadcast state */
1071 	tipc_bcast_remove_peer(n->net, n->bc_entry.link);
1072 
1073 	/* Abort any ongoing link failover */
1074 	for (i = 0; i < MAX_BEARERS; i++) {
1075 		l = n->links[i].link;
1076 		if (l)
1077 			tipc_link_fsm_evt(l, LINK_FAILOVER_END_EVT);
1078 	}
1079 
1080 	/* Notify publications from this node */
1081 	n->action_flags |= TIPC_NOTIFY_NODE_DOWN;
1082 
1083 	/* Notify sockets connected to node */
1084 	list_for_each_entry_safe(conn, safe, conns, list) {
1085 		skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG,
1086 				      SHORT_H_SIZE, 0, tipc_own_addr(n->net),
1087 				      conn->peer_node, conn->port,
1088 				      conn->peer_port, TIPC_ERR_NO_NODE);
1089 		if (likely(skb))
1090 			skb_queue_tail(inputq, skb);
1091 		list_del(&conn->list);
1092 		kfree(conn);
1093 	}
1094 }
1095 
1096 /**
1097  * tipc_node_get_linkname - get the name of a link
1098  *
1099  * @bearer_id: id of the bearer
1100  * @node: peer node address
1101  * @linkname: link name output buffer
1102  *
1103  * Returns 0 on success
1104  */
1105 int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 addr,
1106 			   char *linkname, size_t len)
1107 {
1108 	struct tipc_link *link;
1109 	int err = -EINVAL;
1110 	struct tipc_node *node = tipc_node_find(net, addr);
1111 
1112 	if (!node)
1113 		return err;
1114 
1115 	if (bearer_id >= MAX_BEARERS)
1116 		goto exit;
1117 
1118 	tipc_node_read_lock(node);
1119 	link = node->links[bearer_id].link;
1120 	if (link) {
1121 		strncpy(linkname, tipc_link_name(link), len);
1122 		err = 0;
1123 	}
1124 exit:
1125 	tipc_node_read_unlock(node);
1126 	tipc_node_put(node);
1127 	return err;
1128 }
1129 
1130 /* Caller should hold node lock for the passed node */
1131 static int __tipc_nl_add_node(struct tipc_nl_msg *msg, struct tipc_node *node)
1132 {
1133 	void *hdr;
1134 	struct nlattr *attrs;
1135 
1136 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
1137 			  NLM_F_MULTI, TIPC_NL_NODE_GET);
1138 	if (!hdr)
1139 		return -EMSGSIZE;
1140 
1141 	attrs = nla_nest_start(msg->skb, TIPC_NLA_NODE);
1142 	if (!attrs)
1143 		goto msg_full;
1144 
1145 	if (nla_put_u32(msg->skb, TIPC_NLA_NODE_ADDR, node->addr))
1146 		goto attr_msg_full;
1147 	if (tipc_node_is_up(node))
1148 		if (nla_put_flag(msg->skb, TIPC_NLA_NODE_UP))
1149 			goto attr_msg_full;
1150 
1151 	nla_nest_end(msg->skb, attrs);
1152 	genlmsg_end(msg->skb, hdr);
1153 
1154 	return 0;
1155 
1156 attr_msg_full:
1157 	nla_nest_cancel(msg->skb, attrs);
1158 msg_full:
1159 	genlmsg_cancel(msg->skb, hdr);
1160 
1161 	return -EMSGSIZE;
1162 }
1163 
1164 /**
1165  * tipc_node_xmit() is the general link level function for message sending
1166  * @net: the applicable net namespace
1167  * @list: chain of buffers containing message
1168  * @dnode: address of destination node
1169  * @selector: a number used for deterministic link selection
1170  * Consumes the buffer chain, except when returning -ELINKCONG
1171  * Returns 0 if success, otherwise: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE,-ENOBUF
1172  */
1173 int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
1174 		   u32 dnode, int selector)
1175 {
1176 	struct tipc_link_entry *le = NULL;
1177 	struct tipc_node *n;
1178 	struct sk_buff_head xmitq;
1179 	int bearer_id;
1180 	int rc;
1181 
1182 	if (in_own_node(net, dnode)) {
1183 		tipc_sk_rcv(net, list);
1184 		return 0;
1185 	}
1186 
1187 	n = tipc_node_find(net, dnode);
1188 	if (unlikely(!n)) {
1189 		skb_queue_purge(list);
1190 		return -EHOSTUNREACH;
1191 	}
1192 
1193 	tipc_node_read_lock(n);
1194 	bearer_id = n->active_links[selector & 1];
1195 	if (unlikely(bearer_id == INVALID_BEARER_ID)) {
1196 		tipc_node_read_unlock(n);
1197 		tipc_node_put(n);
1198 		skb_queue_purge(list);
1199 		return -EHOSTUNREACH;
1200 	}
1201 
1202 	__skb_queue_head_init(&xmitq);
1203 	le = &n->links[bearer_id];
1204 	spin_lock_bh(&le->lock);
1205 	rc = tipc_link_xmit(le->link, list, &xmitq);
1206 	spin_unlock_bh(&le->lock);
1207 	tipc_node_read_unlock(n);
1208 
1209 	if (likely(rc == 0))
1210 		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1211 	else if (rc == -ENOBUFS)
1212 		tipc_node_link_down(n, bearer_id, false);
1213 
1214 	tipc_node_put(n);
1215 
1216 	return rc;
1217 }
1218 
1219 /* tipc_node_xmit_skb(): send single buffer to destination
1220  * Buffers sent via this functon are generally TIPC_SYSTEM_IMPORTANCE
1221  * messages, which will not be rejected
1222  * The only exception is datagram messages rerouted after secondary
1223  * lookup, which are rare and safe to dispose of anyway.
1224  * TODO: Return real return value, and let callers use
1225  * tipc_wait_for_sendpkt() where applicable
1226  */
1227 int tipc_node_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
1228 		       u32 selector)
1229 {
1230 	struct sk_buff_head head;
1231 	int rc;
1232 
1233 	skb_queue_head_init(&head);
1234 	__skb_queue_tail(&head, skb);
1235 	rc = tipc_node_xmit(net, &head, dnode, selector);
1236 	if (rc == -ELINKCONG)
1237 		kfree_skb(skb);
1238 	return 0;
1239 }
1240 
1241 void tipc_node_broadcast(struct net *net, struct sk_buff *skb)
1242 {
1243 	struct sk_buff *txskb;
1244 	struct tipc_node *n;
1245 	u32 dst;
1246 
1247 	rcu_read_lock();
1248 	list_for_each_entry_rcu(n, tipc_nodes(net), list) {
1249 		dst = n->addr;
1250 		if (in_own_node(net, dst))
1251 			continue;
1252 		if (!tipc_node_is_up(n))
1253 			continue;
1254 		txskb = pskb_copy(skb, GFP_ATOMIC);
1255 		if (!txskb)
1256 			break;
1257 		msg_set_destnode(buf_msg(txskb), dst);
1258 		tipc_node_xmit_skb(net, txskb, dst, 0);
1259 	}
1260 	rcu_read_unlock();
1261 
1262 	kfree_skb(skb);
1263 }
1264 
1265 static void tipc_node_bc_sync_rcv(struct tipc_node *n, struct tipc_msg *hdr,
1266 				  int bearer_id, struct sk_buff_head *xmitq)
1267 {
1268 	struct tipc_link *ucl;
1269 	int rc;
1270 
1271 	rc = tipc_bcast_sync_rcv(n->net, n->bc_entry.link, hdr);
1272 
1273 	if (rc & TIPC_LINK_DOWN_EVT) {
1274 		tipc_bearer_reset_all(n->net);
1275 		return;
1276 	}
1277 
1278 	if (!(rc & TIPC_LINK_SND_STATE))
1279 		return;
1280 
1281 	/* If probe message, a STATE response will be sent anyway */
1282 	if (msg_probe(hdr))
1283 		return;
1284 
1285 	/* Produce a STATE message carrying broadcast NACK */
1286 	tipc_node_read_lock(n);
1287 	ucl = n->links[bearer_id].link;
1288 	if (ucl)
1289 		tipc_link_build_state_msg(ucl, xmitq);
1290 	tipc_node_read_unlock(n);
1291 }
1292 
1293 /**
1294  * tipc_node_bc_rcv - process TIPC broadcast packet arriving from off-node
1295  * @net: the applicable net namespace
1296  * @skb: TIPC packet
1297  * @bearer_id: id of bearer message arrived on
1298  *
1299  * Invoked with no locks held.
1300  */
1301 static void tipc_node_bc_rcv(struct net *net, struct sk_buff *skb, int bearer_id)
1302 {
1303 	int rc;
1304 	struct sk_buff_head xmitq;
1305 	struct tipc_bclink_entry *be;
1306 	struct tipc_link_entry *le;
1307 	struct tipc_msg *hdr = buf_msg(skb);
1308 	int usr = msg_user(hdr);
1309 	u32 dnode = msg_destnode(hdr);
1310 	struct tipc_node *n;
1311 
1312 	__skb_queue_head_init(&xmitq);
1313 
1314 	/* If NACK for other node, let rcv link for that node peek into it */
1315 	if ((usr == BCAST_PROTOCOL) && (dnode != tipc_own_addr(net)))
1316 		n = tipc_node_find(net, dnode);
1317 	else
1318 		n = tipc_node_find(net, msg_prevnode(hdr));
1319 	if (!n) {
1320 		kfree_skb(skb);
1321 		return;
1322 	}
1323 	be = &n->bc_entry;
1324 	le = &n->links[bearer_id];
1325 
1326 	rc = tipc_bcast_rcv(net, be->link, skb);
1327 
1328 	/* Broadcast ACKs are sent on a unicast link */
1329 	if (rc & TIPC_LINK_SND_STATE) {
1330 		tipc_node_read_lock(n);
1331 		tipc_link_build_state_msg(le->link, &xmitq);
1332 		tipc_node_read_unlock(n);
1333 	}
1334 
1335 	if (!skb_queue_empty(&xmitq))
1336 		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1337 
1338 	/* Deliver. 'arrvq' is under inputq2's lock protection */
1339 	if (!skb_queue_empty(&be->inputq1)) {
1340 		spin_lock_bh(&be->inputq2.lock);
1341 		spin_lock_bh(&be->inputq1.lock);
1342 		skb_queue_splice_tail_init(&be->inputq1, &be->arrvq);
1343 		spin_unlock_bh(&be->inputq1.lock);
1344 		spin_unlock_bh(&be->inputq2.lock);
1345 		tipc_sk_mcast_rcv(net, &be->arrvq, &be->inputq2);
1346 	}
1347 
1348 	if (rc & TIPC_LINK_DOWN_EVT) {
1349 		/* Reception reassembly failure => reset all links to peer */
1350 		if (!tipc_link_is_up(be->link))
1351 			tipc_node_reset_links(n);
1352 
1353 		/* Retransmission failure => reset all links to all peers */
1354 		if (!tipc_link_is_up(tipc_bc_sndlink(net)))
1355 			tipc_bearer_reset_all(net);
1356 	}
1357 
1358 	tipc_node_put(n);
1359 }
1360 
1361 /**
1362  * tipc_node_check_state - check and if necessary update node state
1363  * @skb: TIPC packet
1364  * @bearer_id: identity of bearer delivering the packet
1365  * Returns true if state is ok, otherwise consumes buffer and returns false
1366  */
1367 static bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
1368 				  int bearer_id, struct sk_buff_head *xmitq)
1369 {
1370 	struct tipc_msg *hdr = buf_msg(skb);
1371 	int usr = msg_user(hdr);
1372 	int mtyp = msg_type(hdr);
1373 	u16 oseqno = msg_seqno(hdr);
1374 	u16 iseqno = msg_seqno(msg_get_wrapped(hdr));
1375 	u16 exp_pkts = msg_msgcnt(hdr);
1376 	u16 rcv_nxt, syncpt, dlv_nxt, inputq_len;
1377 	int state = n->state;
1378 	struct tipc_link *l, *tnl, *pl = NULL;
1379 	struct tipc_media_addr *maddr;
1380 	int pb_id;
1381 
1382 	l = n->links[bearer_id].link;
1383 	if (!l)
1384 		return false;
1385 	rcv_nxt = tipc_link_rcv_nxt(l);
1386 
1387 
1388 	if (likely((state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL)))
1389 		return true;
1390 
1391 	/* Find parallel link, if any */
1392 	for (pb_id = 0; pb_id < MAX_BEARERS; pb_id++) {
1393 		if ((pb_id != bearer_id) && n->links[pb_id].link) {
1394 			pl = n->links[pb_id].link;
1395 			break;
1396 		}
1397 	}
1398 
1399 	/* Check and update node accesibility if applicable */
1400 	if (state == SELF_UP_PEER_COMING) {
1401 		if (!tipc_link_is_up(l))
1402 			return true;
1403 		if (!msg_peer_link_is_up(hdr))
1404 			return true;
1405 		tipc_node_fsm_evt(n, PEER_ESTABL_CONTACT_EVT);
1406 	}
1407 
1408 	if (state == SELF_DOWN_PEER_LEAVING) {
1409 		if (msg_peer_node_is_up(hdr))
1410 			return false;
1411 		tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
1412 		return true;
1413 	}
1414 
1415 	if (state == SELF_LEAVING_PEER_DOWN)
1416 		return false;
1417 
1418 	/* Ignore duplicate packets */
1419 	if ((usr != LINK_PROTOCOL) && less(oseqno, rcv_nxt))
1420 		return true;
1421 
1422 	/* Initiate or update failover mode if applicable */
1423 	if ((usr == TUNNEL_PROTOCOL) && (mtyp == FAILOVER_MSG)) {
1424 		syncpt = oseqno + exp_pkts - 1;
1425 		if (pl && tipc_link_is_up(pl)) {
1426 			__tipc_node_link_down(n, &pb_id, xmitq, &maddr);
1427 			tipc_skb_queue_splice_tail_init(tipc_link_inputq(pl),
1428 							tipc_link_inputq(l));
1429 		}
1430 		/* If pkts arrive out of order, use lowest calculated syncpt */
1431 		if (less(syncpt, n->sync_point))
1432 			n->sync_point = syncpt;
1433 	}
1434 
1435 	/* Open parallel link when tunnel link reaches synch point */
1436 	if ((n->state == NODE_FAILINGOVER) && tipc_link_is_up(l)) {
1437 		if (!more(rcv_nxt, n->sync_point))
1438 			return true;
1439 		tipc_node_fsm_evt(n, NODE_FAILOVER_END_EVT);
1440 		if (pl)
1441 			tipc_link_fsm_evt(pl, LINK_FAILOVER_END_EVT);
1442 		return true;
1443 	}
1444 
1445 	/* No synching needed if only one link */
1446 	if (!pl || !tipc_link_is_up(pl))
1447 		return true;
1448 
1449 	/* Initiate synch mode if applicable */
1450 	if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG) && (oseqno == 1)) {
1451 		syncpt = iseqno + exp_pkts - 1;
1452 		if (!tipc_link_is_up(l)) {
1453 			tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
1454 			__tipc_node_link_up(n, bearer_id, xmitq);
1455 		}
1456 		if (n->state == SELF_UP_PEER_UP) {
1457 			n->sync_point = syncpt;
1458 			tipc_link_fsm_evt(l, LINK_SYNCH_BEGIN_EVT);
1459 			tipc_node_fsm_evt(n, NODE_SYNCH_BEGIN_EVT);
1460 		}
1461 	}
1462 
1463 	/* Open tunnel link when parallel link reaches synch point */
1464 	if (n->state == NODE_SYNCHING) {
1465 		if (tipc_link_is_synching(l)) {
1466 			tnl = l;
1467 		} else {
1468 			tnl = pl;
1469 			pl = l;
1470 		}
1471 		inputq_len = skb_queue_len(tipc_link_inputq(pl));
1472 		dlv_nxt = tipc_link_rcv_nxt(pl) - inputq_len;
1473 		if (more(dlv_nxt, n->sync_point)) {
1474 			tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
1475 			tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
1476 			return true;
1477 		}
1478 		if (l == pl)
1479 			return true;
1480 		if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG))
1481 			return true;
1482 		if (usr == LINK_PROTOCOL)
1483 			return true;
1484 		return false;
1485 	}
1486 	return true;
1487 }
1488 
1489 /**
1490  * tipc_rcv - process TIPC packets/messages arriving from off-node
1491  * @net: the applicable net namespace
1492  * @skb: TIPC packet
1493  * @bearer: pointer to bearer message arrived on
1494  *
1495  * Invoked with no locks held. Bearer pointer must point to a valid bearer
1496  * structure (i.e. cannot be NULL), but bearer can be inactive.
1497  */
1498 void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
1499 {
1500 	struct sk_buff_head xmitq;
1501 	struct tipc_node *n;
1502 	struct tipc_msg *hdr = buf_msg(skb);
1503 	int usr = msg_user(hdr);
1504 	int bearer_id = b->identity;
1505 	struct tipc_link_entry *le;
1506 	u16 bc_ack = msg_bcast_ack(hdr);
1507 	u32 self = tipc_own_addr(net);
1508 	int rc = 0;
1509 
1510 	__skb_queue_head_init(&xmitq);
1511 
1512 	/* Ensure message is well-formed */
1513 	if (unlikely(!tipc_msg_validate(skb)))
1514 		goto discard;
1515 
1516 	/* Handle arrival of discovery or broadcast packet */
1517 	if (unlikely(msg_non_seq(hdr))) {
1518 		if (unlikely(usr == LINK_CONFIG))
1519 			return tipc_disc_rcv(net, skb, b);
1520 		else
1521 			return tipc_node_bc_rcv(net, skb, bearer_id);
1522 	}
1523 
1524 	/* Discard unicast link messages destined for another node */
1525 	if (unlikely(!msg_short(hdr) && (msg_destnode(hdr) != self)))
1526 		goto discard;
1527 
1528 	/* Locate neighboring node that sent packet */
1529 	n = tipc_node_find(net, msg_prevnode(hdr));
1530 	if (unlikely(!n))
1531 		goto discard;
1532 	le = &n->links[bearer_id];
1533 
1534 	/* Ensure broadcast reception is in synch with peer's send state */
1535 	if (unlikely(usr == LINK_PROTOCOL))
1536 		tipc_node_bc_sync_rcv(n, hdr, bearer_id, &xmitq);
1537 	else if (unlikely(tipc_link_acked(n->bc_entry.link) != bc_ack))
1538 		tipc_bcast_ack_rcv(net, n->bc_entry.link, hdr);
1539 
1540 	/* Receive packet directly if conditions permit */
1541 	tipc_node_read_lock(n);
1542 	if (likely((n->state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL))) {
1543 		spin_lock_bh(&le->lock);
1544 		if (le->link) {
1545 			rc = tipc_link_rcv(le->link, skb, &xmitq);
1546 			skb = NULL;
1547 		}
1548 		spin_unlock_bh(&le->lock);
1549 	}
1550 	tipc_node_read_unlock(n);
1551 
1552 	/* Check/update node state before receiving */
1553 	if (unlikely(skb)) {
1554 		tipc_node_write_lock(n);
1555 		if (tipc_node_check_state(n, skb, bearer_id, &xmitq)) {
1556 			if (le->link) {
1557 				rc = tipc_link_rcv(le->link, skb, &xmitq);
1558 				skb = NULL;
1559 			}
1560 		}
1561 		tipc_node_write_unlock(n);
1562 	}
1563 
1564 	if (unlikely(rc & TIPC_LINK_UP_EVT))
1565 		tipc_node_link_up(n, bearer_id, &xmitq);
1566 
1567 	if (unlikely(rc & TIPC_LINK_DOWN_EVT))
1568 		tipc_node_link_down(n, bearer_id, false);
1569 
1570 	if (unlikely(!skb_queue_empty(&n->bc_entry.namedq)))
1571 		tipc_named_rcv(net, &n->bc_entry.namedq);
1572 
1573 	if (!skb_queue_empty(&le->inputq))
1574 		tipc_sk_rcv(net, &le->inputq);
1575 
1576 	if (!skb_queue_empty(&xmitq))
1577 		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
1578 
1579 	tipc_node_put(n);
1580 discard:
1581 	kfree_skb(skb);
1582 }
1583 
1584 int tipc_nl_peer_rm(struct sk_buff *skb, struct genl_info *info)
1585 {
1586 	struct net *net = sock_net(skb->sk);
1587 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1588 	struct nlattr *attrs[TIPC_NLA_NET_MAX + 1];
1589 	struct tipc_node *peer;
1590 	u32 addr;
1591 	int err;
1592 	int i;
1593 
1594 	/* We identify the peer by its net */
1595 	if (!info->attrs[TIPC_NLA_NET])
1596 		return -EINVAL;
1597 
1598 	err = nla_parse_nested(attrs, TIPC_NLA_NET_MAX,
1599 			       info->attrs[TIPC_NLA_NET],
1600 			       tipc_nl_net_policy);
1601 	if (err)
1602 		return err;
1603 
1604 	if (!attrs[TIPC_NLA_NET_ADDR])
1605 		return -EINVAL;
1606 
1607 	addr = nla_get_u32(attrs[TIPC_NLA_NET_ADDR]);
1608 
1609 	if (in_own_node(net, addr))
1610 		return -ENOTSUPP;
1611 
1612 	spin_lock_bh(&tn->node_list_lock);
1613 	peer = tipc_node_find(net, addr);
1614 	if (!peer) {
1615 		spin_unlock_bh(&tn->node_list_lock);
1616 		return -ENXIO;
1617 	}
1618 
1619 	tipc_node_write_lock(peer);
1620 	if (peer->state != SELF_DOWN_PEER_DOWN &&
1621 	    peer->state != SELF_DOWN_PEER_LEAVING) {
1622 		tipc_node_write_unlock(peer);
1623 		err = -EBUSY;
1624 		goto err_out;
1625 	}
1626 
1627 	for (i = 0; i < MAX_BEARERS; i++) {
1628 		struct tipc_link_entry *le = &peer->links[i];
1629 
1630 		if (le->link) {
1631 			kfree(le->link);
1632 			le->link = NULL;
1633 			peer->link_cnt--;
1634 		}
1635 	}
1636 	tipc_node_write_unlock(peer);
1637 	tipc_node_delete(peer);
1638 
1639 	err = 0;
1640 err_out:
1641 	tipc_node_put(peer);
1642 	spin_unlock_bh(&tn->node_list_lock);
1643 
1644 	return err;
1645 }
1646 
1647 int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb)
1648 {
1649 	int err;
1650 	struct net *net = sock_net(skb->sk);
1651 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1652 	int done = cb->args[0];
1653 	int last_addr = cb->args[1];
1654 	struct tipc_node *node;
1655 	struct tipc_nl_msg msg;
1656 
1657 	if (done)
1658 		return 0;
1659 
1660 	msg.skb = skb;
1661 	msg.portid = NETLINK_CB(cb->skb).portid;
1662 	msg.seq = cb->nlh->nlmsg_seq;
1663 
1664 	rcu_read_lock();
1665 	if (last_addr) {
1666 		node = tipc_node_find(net, last_addr);
1667 		if (!node) {
1668 			rcu_read_unlock();
1669 			/* We never set seq or call nl_dump_check_consistent()
1670 			 * this means that setting prev_seq here will cause the
1671 			 * consistence check to fail in the netlink callback
1672 			 * handler. Resulting in the NLMSG_DONE message having
1673 			 * the NLM_F_DUMP_INTR flag set if the node state
1674 			 * changed while we released the lock.
1675 			 */
1676 			cb->prev_seq = 1;
1677 			return -EPIPE;
1678 		}
1679 		tipc_node_put(node);
1680 	}
1681 
1682 	list_for_each_entry_rcu(node, &tn->node_list, list) {
1683 		if (last_addr) {
1684 			if (node->addr == last_addr)
1685 				last_addr = 0;
1686 			else
1687 				continue;
1688 		}
1689 
1690 		tipc_node_read_lock(node);
1691 		err = __tipc_nl_add_node(&msg, node);
1692 		if (err) {
1693 			last_addr = node->addr;
1694 			tipc_node_read_unlock(node);
1695 			goto out;
1696 		}
1697 
1698 		tipc_node_read_unlock(node);
1699 	}
1700 	done = 1;
1701 out:
1702 	cb->args[0] = done;
1703 	cb->args[1] = last_addr;
1704 	rcu_read_unlock();
1705 
1706 	return skb->len;
1707 }
1708 
1709 /* tipc_node_find_by_name - locate owner node of link by link's name
1710  * @net: the applicable net namespace
1711  * @name: pointer to link name string
1712  * @bearer_id: pointer to index in 'node->links' array where the link was found.
1713  *
1714  * Returns pointer to node owning the link, or 0 if no matching link is found.
1715  */
1716 static struct tipc_node *tipc_node_find_by_name(struct net *net,
1717 						const char *link_name,
1718 						unsigned int *bearer_id)
1719 {
1720 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1721 	struct tipc_link *l;
1722 	struct tipc_node *n;
1723 	struct tipc_node *found_node = NULL;
1724 	int i;
1725 
1726 	*bearer_id = 0;
1727 	rcu_read_lock();
1728 	list_for_each_entry_rcu(n, &tn->node_list, list) {
1729 		tipc_node_read_lock(n);
1730 		for (i = 0; i < MAX_BEARERS; i++) {
1731 			l = n->links[i].link;
1732 			if (l && !strcmp(tipc_link_name(l), link_name)) {
1733 				*bearer_id = i;
1734 				found_node = n;
1735 				break;
1736 			}
1737 		}
1738 		tipc_node_read_unlock(n);
1739 		if (found_node)
1740 			break;
1741 	}
1742 	rcu_read_unlock();
1743 
1744 	return found_node;
1745 }
1746 
1747 int tipc_nl_node_set_link(struct sk_buff *skb, struct genl_info *info)
1748 {
1749 	int err;
1750 	int res = 0;
1751 	int bearer_id;
1752 	char *name;
1753 	struct tipc_link *link;
1754 	struct tipc_node *node;
1755 	struct sk_buff_head xmitq;
1756 	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1757 	struct net *net = sock_net(skb->sk);
1758 
1759 	__skb_queue_head_init(&xmitq);
1760 
1761 	if (!info->attrs[TIPC_NLA_LINK])
1762 		return -EINVAL;
1763 
1764 	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1765 			       info->attrs[TIPC_NLA_LINK],
1766 			       tipc_nl_link_policy);
1767 	if (err)
1768 		return err;
1769 
1770 	if (!attrs[TIPC_NLA_LINK_NAME])
1771 		return -EINVAL;
1772 
1773 	name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1774 
1775 	if (strcmp(name, tipc_bclink_name) == 0)
1776 		return tipc_nl_bc_link_set(net, attrs);
1777 
1778 	node = tipc_node_find_by_name(net, name, &bearer_id);
1779 	if (!node)
1780 		return -EINVAL;
1781 
1782 	tipc_node_read_lock(node);
1783 
1784 	link = node->links[bearer_id].link;
1785 	if (!link) {
1786 		res = -EINVAL;
1787 		goto out;
1788 	}
1789 
1790 	if (attrs[TIPC_NLA_LINK_PROP]) {
1791 		struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
1792 
1793 		err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
1794 					      props);
1795 		if (err) {
1796 			res = err;
1797 			goto out;
1798 		}
1799 
1800 		if (props[TIPC_NLA_PROP_TOL]) {
1801 			u32 tol;
1802 
1803 			tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
1804 			tipc_link_set_tolerance(link, tol, &xmitq);
1805 		}
1806 		if (props[TIPC_NLA_PROP_PRIO]) {
1807 			u32 prio;
1808 
1809 			prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
1810 			tipc_link_set_prio(link, prio, &xmitq);
1811 		}
1812 		if (props[TIPC_NLA_PROP_WIN]) {
1813 			u32 win;
1814 
1815 			win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
1816 			tipc_link_set_queue_limits(link, win);
1817 		}
1818 	}
1819 
1820 out:
1821 	tipc_node_read_unlock(node);
1822 	tipc_bearer_xmit(net, bearer_id, &xmitq, &node->links[bearer_id].maddr);
1823 	return res;
1824 }
1825 
1826 int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info)
1827 {
1828 	struct net *net = genl_info_net(info);
1829 	struct tipc_nl_msg msg;
1830 	char *name;
1831 	int err;
1832 
1833 	msg.portid = info->snd_portid;
1834 	msg.seq = info->snd_seq;
1835 
1836 	if (!info->attrs[TIPC_NLA_LINK_NAME])
1837 		return -EINVAL;
1838 	name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
1839 
1840 	msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1841 	if (!msg.skb)
1842 		return -ENOMEM;
1843 
1844 	if (strcmp(name, tipc_bclink_name) == 0) {
1845 		err = tipc_nl_add_bc_link(net, &msg);
1846 		if (err) {
1847 			nlmsg_free(msg.skb);
1848 			return err;
1849 		}
1850 	} else {
1851 		int bearer_id;
1852 		struct tipc_node *node;
1853 		struct tipc_link *link;
1854 
1855 		node = tipc_node_find_by_name(net, name, &bearer_id);
1856 		if (!node)
1857 			return -EINVAL;
1858 
1859 		tipc_node_read_lock(node);
1860 		link = node->links[bearer_id].link;
1861 		if (!link) {
1862 			tipc_node_read_unlock(node);
1863 			nlmsg_free(msg.skb);
1864 			return -EINVAL;
1865 		}
1866 
1867 		err = __tipc_nl_add_link(net, &msg, link, 0);
1868 		tipc_node_read_unlock(node);
1869 		if (err) {
1870 			nlmsg_free(msg.skb);
1871 			return err;
1872 		}
1873 	}
1874 
1875 	return genlmsg_reply(msg.skb, info);
1876 }
1877 
1878 int tipc_nl_node_reset_link_stats(struct sk_buff *skb, struct genl_info *info)
1879 {
1880 	int err;
1881 	char *link_name;
1882 	unsigned int bearer_id;
1883 	struct tipc_link *link;
1884 	struct tipc_node *node;
1885 	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
1886 	struct net *net = sock_net(skb->sk);
1887 	struct tipc_link_entry *le;
1888 
1889 	if (!info->attrs[TIPC_NLA_LINK])
1890 		return -EINVAL;
1891 
1892 	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
1893 			       info->attrs[TIPC_NLA_LINK],
1894 			       tipc_nl_link_policy);
1895 	if (err)
1896 		return err;
1897 
1898 	if (!attrs[TIPC_NLA_LINK_NAME])
1899 		return -EINVAL;
1900 
1901 	link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
1902 
1903 	if (strcmp(link_name, tipc_bclink_name) == 0) {
1904 		err = tipc_bclink_reset_stats(net);
1905 		if (err)
1906 			return err;
1907 		return 0;
1908 	}
1909 
1910 	node = tipc_node_find_by_name(net, link_name, &bearer_id);
1911 	if (!node)
1912 		return -EINVAL;
1913 
1914 	le = &node->links[bearer_id];
1915 	tipc_node_read_lock(node);
1916 	spin_lock_bh(&le->lock);
1917 	link = node->links[bearer_id].link;
1918 	if (!link) {
1919 		spin_unlock_bh(&le->lock);
1920 		tipc_node_read_unlock(node);
1921 		return -EINVAL;
1922 	}
1923 	tipc_link_reset_stats(link);
1924 	spin_unlock_bh(&le->lock);
1925 	tipc_node_read_unlock(node);
1926 	return 0;
1927 }
1928 
1929 /* Caller should hold node lock  */
1930 static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
1931 				    struct tipc_node *node, u32 *prev_link)
1932 {
1933 	u32 i;
1934 	int err;
1935 
1936 	for (i = *prev_link; i < MAX_BEARERS; i++) {
1937 		*prev_link = i;
1938 
1939 		if (!node->links[i].link)
1940 			continue;
1941 
1942 		err = __tipc_nl_add_link(net, msg,
1943 					 node->links[i].link, NLM_F_MULTI);
1944 		if (err)
1945 			return err;
1946 	}
1947 	*prev_link = 0;
1948 
1949 	return 0;
1950 }
1951 
1952 int tipc_nl_node_dump_link(struct sk_buff *skb, struct netlink_callback *cb)
1953 {
1954 	struct net *net = sock_net(skb->sk);
1955 	struct tipc_net *tn = net_generic(net, tipc_net_id);
1956 	struct tipc_node *node;
1957 	struct tipc_nl_msg msg;
1958 	u32 prev_node = cb->args[0];
1959 	u32 prev_link = cb->args[1];
1960 	int done = cb->args[2];
1961 	int err;
1962 
1963 	if (done)
1964 		return 0;
1965 
1966 	msg.skb = skb;
1967 	msg.portid = NETLINK_CB(cb->skb).portid;
1968 	msg.seq = cb->nlh->nlmsg_seq;
1969 
1970 	rcu_read_lock();
1971 	if (prev_node) {
1972 		node = tipc_node_find(net, prev_node);
1973 		if (!node) {
1974 			/* We never set seq or call nl_dump_check_consistent()
1975 			 * this means that setting prev_seq here will cause the
1976 			 * consistence check to fail in the netlink callback
1977 			 * handler. Resulting in the last NLMSG_DONE message
1978 			 * having the NLM_F_DUMP_INTR flag set.
1979 			 */
1980 			cb->prev_seq = 1;
1981 			goto out;
1982 		}
1983 		tipc_node_put(node);
1984 
1985 		list_for_each_entry_continue_rcu(node, &tn->node_list,
1986 						 list) {
1987 			tipc_node_read_lock(node);
1988 			err = __tipc_nl_add_node_links(net, &msg, node,
1989 						       &prev_link);
1990 			tipc_node_read_unlock(node);
1991 			if (err)
1992 				goto out;
1993 
1994 			prev_node = node->addr;
1995 		}
1996 	} else {
1997 		err = tipc_nl_add_bc_link(net, &msg);
1998 		if (err)
1999 			goto out;
2000 
2001 		list_for_each_entry_rcu(node, &tn->node_list, list) {
2002 			tipc_node_read_lock(node);
2003 			err = __tipc_nl_add_node_links(net, &msg, node,
2004 						       &prev_link);
2005 			tipc_node_read_unlock(node);
2006 			if (err)
2007 				goto out;
2008 
2009 			prev_node = node->addr;
2010 		}
2011 	}
2012 	done = 1;
2013 out:
2014 	rcu_read_unlock();
2015 
2016 	cb->args[0] = prev_node;
2017 	cb->args[1] = prev_link;
2018 	cb->args[2] = done;
2019 
2020 	return skb->len;
2021 }
2022 
2023 int tipc_nl_node_set_monitor(struct sk_buff *skb, struct genl_info *info)
2024 {
2025 	struct nlattr *attrs[TIPC_NLA_MON_MAX + 1];
2026 	struct net *net = sock_net(skb->sk);
2027 	int err;
2028 
2029 	if (!info->attrs[TIPC_NLA_MON])
2030 		return -EINVAL;
2031 
2032 	err = nla_parse_nested(attrs, TIPC_NLA_MON_MAX,
2033 			       info->attrs[TIPC_NLA_MON],
2034 			       tipc_nl_monitor_policy);
2035 	if (err)
2036 		return err;
2037 
2038 	if (attrs[TIPC_NLA_MON_ACTIVATION_THRESHOLD]) {
2039 		u32 val;
2040 
2041 		val = nla_get_u32(attrs[TIPC_NLA_MON_ACTIVATION_THRESHOLD]);
2042 		err = tipc_nl_monitor_set_threshold(net, val);
2043 		if (err)
2044 			return err;
2045 	}
2046 
2047 	return 0;
2048 }
2049 
2050 static int __tipc_nl_add_monitor_prop(struct net *net, struct tipc_nl_msg *msg)
2051 {
2052 	struct nlattr *attrs;
2053 	void *hdr;
2054 	u32 val;
2055 
2056 	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
2057 			  0, TIPC_NL_MON_GET);
2058 	if (!hdr)
2059 		return -EMSGSIZE;
2060 
2061 	attrs = nla_nest_start(msg->skb, TIPC_NLA_MON);
2062 	if (!attrs)
2063 		goto msg_full;
2064 
2065 	val = tipc_nl_monitor_get_threshold(net);
2066 
2067 	if (nla_put_u32(msg->skb, TIPC_NLA_MON_ACTIVATION_THRESHOLD, val))
2068 		goto attr_msg_full;
2069 
2070 	nla_nest_end(msg->skb, attrs);
2071 	genlmsg_end(msg->skb, hdr);
2072 
2073 	return 0;
2074 
2075 attr_msg_full:
2076 	nla_nest_cancel(msg->skb, attrs);
2077 msg_full:
2078 	genlmsg_cancel(msg->skb, hdr);
2079 
2080 	return -EMSGSIZE;
2081 }
2082 
2083 int tipc_nl_node_get_monitor(struct sk_buff *skb, struct genl_info *info)
2084 {
2085 	struct net *net = sock_net(skb->sk);
2086 	struct tipc_nl_msg msg;
2087 	int err;
2088 
2089 	msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
2090 	msg.portid = info->snd_portid;
2091 	msg.seq = info->snd_seq;
2092 
2093 	err = __tipc_nl_add_monitor_prop(net, &msg);
2094 	if (err) {
2095 		nlmsg_free(msg.skb);
2096 		return err;
2097 	}
2098 
2099 	return genlmsg_reply(msg.skb, info);
2100 }
2101 
2102 int tipc_nl_node_dump_monitor(struct sk_buff *skb, struct netlink_callback *cb)
2103 {
2104 	struct net *net = sock_net(skb->sk);
2105 	u32 prev_bearer = cb->args[0];
2106 	struct tipc_nl_msg msg;
2107 	int err;
2108 	int i;
2109 
2110 	if (prev_bearer == MAX_BEARERS)
2111 		return 0;
2112 
2113 	msg.skb = skb;
2114 	msg.portid = NETLINK_CB(cb->skb).portid;
2115 	msg.seq = cb->nlh->nlmsg_seq;
2116 
2117 	rtnl_lock();
2118 	for (i = prev_bearer; i < MAX_BEARERS; i++) {
2119 		prev_bearer = i;
2120 		err = __tipc_nl_add_monitor(net, &msg, prev_bearer);
2121 		if (err)
2122 			goto out;
2123 	}
2124 
2125 out:
2126 	rtnl_unlock();
2127 	cb->args[0] = prev_bearer;
2128 
2129 	return skb->len;
2130 }
2131 
2132 int tipc_nl_node_dump_monitor_peer(struct sk_buff *skb,
2133 				   struct netlink_callback *cb)
2134 {
2135 	struct net *net = sock_net(skb->sk);
2136 	u32 prev_node = cb->args[1];
2137 	u32 bearer_id = cb->args[2];
2138 	int done = cb->args[0];
2139 	struct tipc_nl_msg msg;
2140 	int err;
2141 
2142 	if (!prev_node) {
2143 		struct nlattr **attrs;
2144 		struct nlattr *mon[TIPC_NLA_MON_MAX + 1];
2145 
2146 		err = tipc_nlmsg_parse(cb->nlh, &attrs);
2147 		if (err)
2148 			return err;
2149 
2150 		if (!attrs[TIPC_NLA_MON])
2151 			return -EINVAL;
2152 
2153 		err = nla_parse_nested(mon, TIPC_NLA_MON_MAX,
2154 				       attrs[TIPC_NLA_MON],
2155 				       tipc_nl_monitor_policy);
2156 		if (err)
2157 			return err;
2158 
2159 		if (!mon[TIPC_NLA_MON_REF])
2160 			return -EINVAL;
2161 
2162 		bearer_id = nla_get_u32(mon[TIPC_NLA_MON_REF]);
2163 
2164 		if (bearer_id >= MAX_BEARERS)
2165 			return -EINVAL;
2166 	}
2167 
2168 	if (done)
2169 		return 0;
2170 
2171 	msg.skb = skb;
2172 	msg.portid = NETLINK_CB(cb->skb).portid;
2173 	msg.seq = cb->nlh->nlmsg_seq;
2174 
2175 	rtnl_lock();
2176 	err = tipc_nl_add_monitor_peer(net, &msg, bearer_id, &prev_node);
2177 	if (!err)
2178 		done = 1;
2179 
2180 	rtnl_unlock();
2181 	cb->args[0] = done;
2182 	cb->args[1] = prev_node;
2183 	cb->args[2] = bearer_id;
2184 
2185 	return skb->len;
2186 }
2187