xref: /openbmc/linux/net/batman-adv/originator.c (revision 81d67439)
1 /*
2  * Copyright (C) 2009-2011 B.A.T.M.A.N. contributors:
3  *
4  * Marek Lindner, Simon Wunderlich
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of version 2 of the GNU General Public
8  * License as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18  * 02110-1301, USA
19  *
20  */
21 
22 #include "main.h"
23 #include "originator.h"
24 #include "hash.h"
25 #include "translation-table.h"
26 #include "routing.h"
27 #include "gateway_client.h"
28 #include "hard-interface.h"
29 #include "unicast.h"
30 #include "soft-interface.h"
31 
32 static void purge_orig(struct work_struct *work);
33 
34 static void start_purge_timer(struct bat_priv *bat_priv)
35 {
36 	INIT_DELAYED_WORK(&bat_priv->orig_work, purge_orig);
37 	queue_delayed_work(bat_event_workqueue, &bat_priv->orig_work, 1 * HZ);
38 }
39 
40 /* returns 1 if they are the same originator */
41 static int compare_orig(const struct hlist_node *node, const void *data2)
42 {
43 	const void *data1 = container_of(node, struct orig_node, hash_entry);
44 
45 	return (memcmp(data1, data2, ETH_ALEN) == 0 ? 1 : 0);
46 }
47 
48 int originator_init(struct bat_priv *bat_priv)
49 {
50 	if (bat_priv->orig_hash)
51 		return 1;
52 
53 	bat_priv->orig_hash = hash_new(1024);
54 
55 	if (!bat_priv->orig_hash)
56 		goto err;
57 
58 	start_purge_timer(bat_priv);
59 	return 1;
60 
61 err:
62 	return 0;
63 }
64 
65 void neigh_node_free_ref(struct neigh_node *neigh_node)
66 {
67 	if (atomic_dec_and_test(&neigh_node->refcount))
68 		kfree_rcu(neigh_node, rcu);
69 }
70 
71 /* increases the refcounter of a found router */
72 struct neigh_node *orig_node_get_router(struct orig_node *orig_node)
73 {
74 	struct neigh_node *router;
75 
76 	rcu_read_lock();
77 	router = rcu_dereference(orig_node->router);
78 
79 	if (router && !atomic_inc_not_zero(&router->refcount))
80 		router = NULL;
81 
82 	rcu_read_unlock();
83 	return router;
84 }
85 
86 struct neigh_node *create_neighbor(struct orig_node *orig_node,
87 				   struct orig_node *orig_neigh_node,
88 				   const uint8_t *neigh,
89 				   struct hard_iface *if_incoming)
90 {
91 	struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
92 	struct neigh_node *neigh_node;
93 
94 	bat_dbg(DBG_BATMAN, bat_priv,
95 		"Creating new last-hop neighbor of originator\n");
96 
97 	neigh_node = kzalloc(sizeof(*neigh_node), GFP_ATOMIC);
98 	if (!neigh_node)
99 		return NULL;
100 
101 	INIT_HLIST_NODE(&neigh_node->list);
102 	INIT_LIST_HEAD(&neigh_node->bonding_list);
103 	spin_lock_init(&neigh_node->tq_lock);
104 
105 	memcpy(neigh_node->addr, neigh, ETH_ALEN);
106 	neigh_node->orig_node = orig_neigh_node;
107 	neigh_node->if_incoming = if_incoming;
108 
109 	/* extra reference for return */
110 	atomic_set(&neigh_node->refcount, 2);
111 
112 	spin_lock_bh(&orig_node->neigh_list_lock);
113 	hlist_add_head_rcu(&neigh_node->list, &orig_node->neigh_list);
114 	spin_unlock_bh(&orig_node->neigh_list_lock);
115 	return neigh_node;
116 }
117 
118 static void orig_node_free_rcu(struct rcu_head *rcu)
119 {
120 	struct hlist_node *node, *node_tmp;
121 	struct neigh_node *neigh_node, *tmp_neigh_node;
122 	struct orig_node *orig_node;
123 
124 	orig_node = container_of(rcu, struct orig_node, rcu);
125 
126 	spin_lock_bh(&orig_node->neigh_list_lock);
127 
128 	/* for all bonding members ... */
129 	list_for_each_entry_safe(neigh_node, tmp_neigh_node,
130 				 &orig_node->bond_list, bonding_list) {
131 		list_del_rcu(&neigh_node->bonding_list);
132 		neigh_node_free_ref(neigh_node);
133 	}
134 
135 	/* for all neighbors towards this originator ... */
136 	hlist_for_each_entry_safe(neigh_node, node, node_tmp,
137 				  &orig_node->neigh_list, list) {
138 		hlist_del_rcu(&neigh_node->list);
139 		neigh_node_free_ref(neigh_node);
140 	}
141 
142 	spin_unlock_bh(&orig_node->neigh_list_lock);
143 
144 	frag_list_free(&orig_node->frag_list);
145 	tt_global_del_orig(orig_node->bat_priv, orig_node,
146 			    "originator timed out");
147 
148 	kfree(orig_node->tt_buff);
149 	kfree(orig_node->bcast_own);
150 	kfree(orig_node->bcast_own_sum);
151 	kfree(orig_node);
152 }
153 
154 void orig_node_free_ref(struct orig_node *orig_node)
155 {
156 	if (atomic_dec_and_test(&orig_node->refcount))
157 		call_rcu(&orig_node->rcu, orig_node_free_rcu);
158 }
159 
160 void originator_free(struct bat_priv *bat_priv)
161 {
162 	struct hashtable_t *hash = bat_priv->orig_hash;
163 	struct hlist_node *node, *node_tmp;
164 	struct hlist_head *head;
165 	spinlock_t *list_lock; /* spinlock to protect write access */
166 	struct orig_node *orig_node;
167 	int i;
168 
169 	if (!hash)
170 		return;
171 
172 	cancel_delayed_work_sync(&bat_priv->orig_work);
173 
174 	bat_priv->orig_hash = NULL;
175 
176 	for (i = 0; i < hash->size; i++) {
177 		head = &hash->table[i];
178 		list_lock = &hash->list_locks[i];
179 
180 		spin_lock_bh(list_lock);
181 		hlist_for_each_entry_safe(orig_node, node, node_tmp,
182 					  head, hash_entry) {
183 
184 			hlist_del_rcu(node);
185 			orig_node_free_ref(orig_node);
186 		}
187 		spin_unlock_bh(list_lock);
188 	}
189 
190 	hash_destroy(hash);
191 }
192 
193 /* this function finds or creates an originator entry for the given
194  * address if it does not exits */
195 struct orig_node *get_orig_node(struct bat_priv *bat_priv, const uint8_t *addr)
196 {
197 	struct orig_node *orig_node;
198 	int size;
199 	int hash_added;
200 
201 	orig_node = orig_hash_find(bat_priv, addr);
202 	if (orig_node)
203 		return orig_node;
204 
205 	bat_dbg(DBG_BATMAN, bat_priv,
206 		"Creating new originator: %pM\n", addr);
207 
208 	orig_node = kzalloc(sizeof(*orig_node), GFP_ATOMIC);
209 	if (!orig_node)
210 		return NULL;
211 
212 	INIT_HLIST_HEAD(&orig_node->neigh_list);
213 	INIT_LIST_HEAD(&orig_node->bond_list);
214 	spin_lock_init(&orig_node->ogm_cnt_lock);
215 	spin_lock_init(&orig_node->bcast_seqno_lock);
216 	spin_lock_init(&orig_node->neigh_list_lock);
217 	spin_lock_init(&orig_node->tt_buff_lock);
218 
219 	/* extra reference for return */
220 	atomic_set(&orig_node->refcount, 2);
221 
222 	orig_node->tt_poss_change = false;
223 	orig_node->bat_priv = bat_priv;
224 	memcpy(orig_node->orig, addr, ETH_ALEN);
225 	orig_node->router = NULL;
226 	orig_node->tt_crc = 0;
227 	atomic_set(&orig_node->last_ttvn, 0);
228 	orig_node->tt_buff = NULL;
229 	orig_node->tt_buff_len = 0;
230 	atomic_set(&orig_node->tt_size, 0);
231 	orig_node->bcast_seqno_reset = jiffies - 1
232 					- msecs_to_jiffies(RESET_PROTECTION_MS);
233 	orig_node->batman_seqno_reset = jiffies - 1
234 					- msecs_to_jiffies(RESET_PROTECTION_MS);
235 
236 	atomic_set(&orig_node->bond_candidates, 0);
237 
238 	size = bat_priv->num_ifaces * sizeof(unsigned long) * NUM_WORDS;
239 
240 	orig_node->bcast_own = kzalloc(size, GFP_ATOMIC);
241 	if (!orig_node->bcast_own)
242 		goto free_orig_node;
243 
244 	size = bat_priv->num_ifaces * sizeof(uint8_t);
245 	orig_node->bcast_own_sum = kzalloc(size, GFP_ATOMIC);
246 
247 	INIT_LIST_HEAD(&orig_node->frag_list);
248 	orig_node->last_frag_packet = 0;
249 
250 	if (!orig_node->bcast_own_sum)
251 		goto free_bcast_own;
252 
253 	hash_added = hash_add(bat_priv->orig_hash, compare_orig,
254 			      choose_orig, orig_node, &orig_node->hash_entry);
255 	if (hash_added < 0)
256 		goto free_bcast_own_sum;
257 
258 	return orig_node;
259 free_bcast_own_sum:
260 	kfree(orig_node->bcast_own_sum);
261 free_bcast_own:
262 	kfree(orig_node->bcast_own);
263 free_orig_node:
264 	kfree(orig_node);
265 	return NULL;
266 }
267 
268 static bool purge_orig_neighbors(struct bat_priv *bat_priv,
269 				 struct orig_node *orig_node,
270 				 struct neigh_node **best_neigh_node)
271 {
272 	struct hlist_node *node, *node_tmp;
273 	struct neigh_node *neigh_node;
274 	bool neigh_purged = false;
275 
276 	*best_neigh_node = NULL;
277 
278 	spin_lock_bh(&orig_node->neigh_list_lock);
279 
280 	/* for all neighbors towards this originator ... */
281 	hlist_for_each_entry_safe(neigh_node, node, node_tmp,
282 				  &orig_node->neigh_list, list) {
283 
284 		if ((time_after(jiffies,
285 			neigh_node->last_valid + PURGE_TIMEOUT * HZ)) ||
286 		    (neigh_node->if_incoming->if_status == IF_INACTIVE) ||
287 		    (neigh_node->if_incoming->if_status == IF_NOT_IN_USE) ||
288 		    (neigh_node->if_incoming->if_status == IF_TO_BE_REMOVED)) {
289 
290 			if ((neigh_node->if_incoming->if_status ==
291 								IF_INACTIVE) ||
292 			    (neigh_node->if_incoming->if_status ==
293 							IF_NOT_IN_USE) ||
294 			    (neigh_node->if_incoming->if_status ==
295 							IF_TO_BE_REMOVED))
296 				bat_dbg(DBG_BATMAN, bat_priv,
297 					"neighbor purge: originator %pM, "
298 					"neighbor: %pM, iface: %s\n",
299 					orig_node->orig, neigh_node->addr,
300 					neigh_node->if_incoming->net_dev->name);
301 			else
302 				bat_dbg(DBG_BATMAN, bat_priv,
303 					"neighbor timeout: originator %pM, "
304 					"neighbor: %pM, last_valid: %lu\n",
305 					orig_node->orig, neigh_node->addr,
306 					(neigh_node->last_valid / HZ));
307 
308 			neigh_purged = true;
309 
310 			hlist_del_rcu(&neigh_node->list);
311 			bonding_candidate_del(orig_node, neigh_node);
312 			neigh_node_free_ref(neigh_node);
313 		} else {
314 			if ((!*best_neigh_node) ||
315 			    (neigh_node->tq_avg > (*best_neigh_node)->tq_avg))
316 				*best_neigh_node = neigh_node;
317 		}
318 	}
319 
320 	spin_unlock_bh(&orig_node->neigh_list_lock);
321 	return neigh_purged;
322 }
323 
324 static bool purge_orig_node(struct bat_priv *bat_priv,
325 			    struct orig_node *orig_node)
326 {
327 	struct neigh_node *best_neigh_node;
328 
329 	if (time_after(jiffies,
330 		orig_node->last_valid + 2 * PURGE_TIMEOUT * HZ)) {
331 
332 		bat_dbg(DBG_BATMAN, bat_priv,
333 			"Originator timeout: originator %pM, last_valid %lu\n",
334 			orig_node->orig, (orig_node->last_valid / HZ));
335 		return true;
336 	} else {
337 		if (purge_orig_neighbors(bat_priv, orig_node,
338 							&best_neigh_node)) {
339 			update_routes(bat_priv, orig_node,
340 				      best_neigh_node);
341 		}
342 	}
343 
344 	return false;
345 }
346 
347 static void _purge_orig(struct bat_priv *bat_priv)
348 {
349 	struct hashtable_t *hash = bat_priv->orig_hash;
350 	struct hlist_node *node, *node_tmp;
351 	struct hlist_head *head;
352 	spinlock_t *list_lock; /* spinlock to protect write access */
353 	struct orig_node *orig_node;
354 	int i;
355 
356 	if (!hash)
357 		return;
358 
359 	/* for all origins... */
360 	for (i = 0; i < hash->size; i++) {
361 		head = &hash->table[i];
362 		list_lock = &hash->list_locks[i];
363 
364 		spin_lock_bh(list_lock);
365 		hlist_for_each_entry_safe(orig_node, node, node_tmp,
366 					  head, hash_entry) {
367 			if (purge_orig_node(bat_priv, orig_node)) {
368 				if (orig_node->gw_flags)
369 					gw_node_delete(bat_priv, orig_node);
370 				hlist_del_rcu(node);
371 				orig_node_free_ref(orig_node);
372 				continue;
373 			}
374 
375 			if (time_after(jiffies, orig_node->last_frag_packet +
376 						msecs_to_jiffies(FRAG_TIMEOUT)))
377 				frag_list_free(&orig_node->frag_list);
378 		}
379 		spin_unlock_bh(list_lock);
380 	}
381 
382 	gw_node_purge(bat_priv);
383 	gw_election(bat_priv);
384 
385 	softif_neigh_purge(bat_priv);
386 }
387 
388 static void purge_orig(struct work_struct *work)
389 {
390 	struct delayed_work *delayed_work =
391 		container_of(work, struct delayed_work, work);
392 	struct bat_priv *bat_priv =
393 		container_of(delayed_work, struct bat_priv, orig_work);
394 
395 	_purge_orig(bat_priv);
396 	start_purge_timer(bat_priv);
397 }
398 
399 void purge_orig_ref(struct bat_priv *bat_priv)
400 {
401 	_purge_orig(bat_priv);
402 }
403 
404 int orig_seq_print_text(struct seq_file *seq, void *offset)
405 {
406 	struct net_device *net_dev = (struct net_device *)seq->private;
407 	struct bat_priv *bat_priv = netdev_priv(net_dev);
408 	struct hashtable_t *hash = bat_priv->orig_hash;
409 	struct hlist_node *node, *node_tmp;
410 	struct hlist_head *head;
411 	struct hard_iface *primary_if;
412 	struct orig_node *orig_node;
413 	struct neigh_node *neigh_node, *neigh_node_tmp;
414 	int batman_count = 0;
415 	int last_seen_secs;
416 	int last_seen_msecs;
417 	int i, ret = 0;
418 
419 	primary_if = primary_if_get_selected(bat_priv);
420 
421 	if (!primary_if) {
422 		ret = seq_printf(seq, "BATMAN mesh %s disabled - "
423 				 "please specify interfaces to enable it\n",
424 				 net_dev->name);
425 		goto out;
426 	}
427 
428 	if (primary_if->if_status != IF_ACTIVE) {
429 		ret = seq_printf(seq, "BATMAN mesh %s "
430 				 "disabled - primary interface not active\n",
431 				 net_dev->name);
432 		goto out;
433 	}
434 
435 	seq_printf(seq, "[B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
436 		   SOURCE_VERSION, primary_if->net_dev->name,
437 		   primary_if->net_dev->dev_addr, net_dev->name);
438 	seq_printf(seq, "  %-15s %s (%s/%i) %17s [%10s]: %20s ...\n",
439 		   "Originator", "last-seen", "#", TQ_MAX_VALUE, "Nexthop",
440 		   "outgoingIF", "Potential nexthops");
441 
442 	for (i = 0; i < hash->size; i++) {
443 		head = &hash->table[i];
444 
445 		rcu_read_lock();
446 		hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
447 			neigh_node = orig_node_get_router(orig_node);
448 			if (!neigh_node)
449 				continue;
450 
451 			if (neigh_node->tq_avg == 0)
452 				goto next;
453 
454 			last_seen_secs = jiffies_to_msecs(jiffies -
455 						orig_node->last_valid) / 1000;
456 			last_seen_msecs = jiffies_to_msecs(jiffies -
457 						orig_node->last_valid) % 1000;
458 
459 			seq_printf(seq, "%pM %4i.%03is   (%3i) %pM [%10s]:",
460 				   orig_node->orig, last_seen_secs,
461 				   last_seen_msecs, neigh_node->tq_avg,
462 				   neigh_node->addr,
463 				   neigh_node->if_incoming->net_dev->name);
464 
465 			hlist_for_each_entry_rcu(neigh_node_tmp, node_tmp,
466 						 &orig_node->neigh_list, list) {
467 				seq_printf(seq, " %pM (%3i)",
468 					   neigh_node_tmp->addr,
469 					   neigh_node_tmp->tq_avg);
470 			}
471 
472 			seq_printf(seq, "\n");
473 			batman_count++;
474 
475 next:
476 			neigh_node_free_ref(neigh_node);
477 		}
478 		rcu_read_unlock();
479 	}
480 
481 	if (batman_count == 0)
482 		seq_printf(seq, "No batman nodes in range ...\n");
483 
484 out:
485 	if (primary_if)
486 		hardif_free_ref(primary_if);
487 	return ret;
488 }
489 
490 static int orig_node_add_if(struct orig_node *orig_node, int max_if_num)
491 {
492 	void *data_ptr;
493 
494 	data_ptr = kmalloc(max_if_num * sizeof(unsigned long) * NUM_WORDS,
495 			   GFP_ATOMIC);
496 	if (!data_ptr) {
497 		pr_err("Can't resize orig: out of memory\n");
498 		return -1;
499 	}
500 
501 	memcpy(data_ptr, orig_node->bcast_own,
502 	       (max_if_num - 1) * sizeof(unsigned long) * NUM_WORDS);
503 	kfree(orig_node->bcast_own);
504 	orig_node->bcast_own = data_ptr;
505 
506 	data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC);
507 	if (!data_ptr) {
508 		pr_err("Can't resize orig: out of memory\n");
509 		return -1;
510 	}
511 
512 	memcpy(data_ptr, orig_node->bcast_own_sum,
513 	       (max_if_num - 1) * sizeof(uint8_t));
514 	kfree(orig_node->bcast_own_sum);
515 	orig_node->bcast_own_sum = data_ptr;
516 
517 	return 0;
518 }
519 
520 int orig_hash_add_if(struct hard_iface *hard_iface, int max_if_num)
521 {
522 	struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
523 	struct hashtable_t *hash = bat_priv->orig_hash;
524 	struct hlist_node *node;
525 	struct hlist_head *head;
526 	struct orig_node *orig_node;
527 	int i, ret;
528 
529 	/* resize all orig nodes because orig_node->bcast_own(_sum) depend on
530 	 * if_num */
531 	for (i = 0; i < hash->size; i++) {
532 		head = &hash->table[i];
533 
534 		rcu_read_lock();
535 		hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
536 			spin_lock_bh(&orig_node->ogm_cnt_lock);
537 			ret = orig_node_add_if(orig_node, max_if_num);
538 			spin_unlock_bh(&orig_node->ogm_cnt_lock);
539 
540 			if (ret == -1)
541 				goto err;
542 		}
543 		rcu_read_unlock();
544 	}
545 
546 	return 0;
547 
548 err:
549 	rcu_read_unlock();
550 	return -ENOMEM;
551 }
552 
553 static int orig_node_del_if(struct orig_node *orig_node,
554 		     int max_if_num, int del_if_num)
555 {
556 	void *data_ptr = NULL;
557 	int chunk_size;
558 
559 	/* last interface was removed */
560 	if (max_if_num == 0)
561 		goto free_bcast_own;
562 
563 	chunk_size = sizeof(unsigned long) * NUM_WORDS;
564 	data_ptr = kmalloc(max_if_num * chunk_size, GFP_ATOMIC);
565 	if (!data_ptr) {
566 		pr_err("Can't resize orig: out of memory\n");
567 		return -1;
568 	}
569 
570 	/* copy first part */
571 	memcpy(data_ptr, orig_node->bcast_own, del_if_num * chunk_size);
572 
573 	/* copy second part */
574 	memcpy((char *)data_ptr + del_if_num * chunk_size,
575 	       orig_node->bcast_own + ((del_if_num + 1) * chunk_size),
576 	       (max_if_num - del_if_num) * chunk_size);
577 
578 free_bcast_own:
579 	kfree(orig_node->bcast_own);
580 	orig_node->bcast_own = data_ptr;
581 
582 	if (max_if_num == 0)
583 		goto free_own_sum;
584 
585 	data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC);
586 	if (!data_ptr) {
587 		pr_err("Can't resize orig: out of memory\n");
588 		return -1;
589 	}
590 
591 	memcpy(data_ptr, orig_node->bcast_own_sum,
592 	       del_if_num * sizeof(uint8_t));
593 
594 	memcpy((char *)data_ptr + del_if_num * sizeof(uint8_t),
595 	       orig_node->bcast_own_sum + ((del_if_num + 1) * sizeof(uint8_t)),
596 	       (max_if_num - del_if_num) * sizeof(uint8_t));
597 
598 free_own_sum:
599 	kfree(orig_node->bcast_own_sum);
600 	orig_node->bcast_own_sum = data_ptr;
601 
602 	return 0;
603 }
604 
605 int orig_hash_del_if(struct hard_iface *hard_iface, int max_if_num)
606 {
607 	struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
608 	struct hashtable_t *hash = bat_priv->orig_hash;
609 	struct hlist_node *node;
610 	struct hlist_head *head;
611 	struct hard_iface *hard_iface_tmp;
612 	struct orig_node *orig_node;
613 	int i, ret;
614 
615 	/* resize all orig nodes because orig_node->bcast_own(_sum) depend on
616 	 * if_num */
617 	for (i = 0; i < hash->size; i++) {
618 		head = &hash->table[i];
619 
620 		rcu_read_lock();
621 		hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
622 			spin_lock_bh(&orig_node->ogm_cnt_lock);
623 			ret = orig_node_del_if(orig_node, max_if_num,
624 					hard_iface->if_num);
625 			spin_unlock_bh(&orig_node->ogm_cnt_lock);
626 
627 			if (ret == -1)
628 				goto err;
629 		}
630 		rcu_read_unlock();
631 	}
632 
633 	/* renumber remaining batman interfaces _inside_ of orig_hash_lock */
634 	rcu_read_lock();
635 	list_for_each_entry_rcu(hard_iface_tmp, &hardif_list, list) {
636 		if (hard_iface_tmp->if_status == IF_NOT_IN_USE)
637 			continue;
638 
639 		if (hard_iface == hard_iface_tmp)
640 			continue;
641 
642 		if (hard_iface->soft_iface != hard_iface_tmp->soft_iface)
643 			continue;
644 
645 		if (hard_iface_tmp->if_num > hard_iface->if_num)
646 			hard_iface_tmp->if_num--;
647 	}
648 	rcu_read_unlock();
649 
650 	hard_iface->if_num = -1;
651 	return 0;
652 
653 err:
654 	rcu_read_unlock();
655 	return -ENOMEM;
656 }
657