xref: /openbmc/linux/net/batman-adv/originator.c (revision b6bec26c)
1 /* Copyright (C) 2009-2012 B.A.T.M.A.N. contributors:
2  *
3  * Marek Lindner, Simon Wunderlich
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of version 2 of the GNU General Public
7  * License as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17  * 02110-1301, USA
18  */
19 
20 #include "main.h"
21 #include "distributed-arp-table.h"
22 #include "originator.h"
23 #include "hash.h"
24 #include "translation-table.h"
25 #include "routing.h"
26 #include "gateway_client.h"
27 #include "hard-interface.h"
28 #include "unicast.h"
29 #include "soft-interface.h"
30 #include "bridge_loop_avoidance.h"
31 
32 static void batadv_purge_orig(struct work_struct *work);
33 
34 static void batadv_start_purge_timer(struct batadv_priv *bat_priv)
35 {
36 	INIT_DELAYED_WORK(&bat_priv->orig_work, batadv_purge_orig);
37 	queue_delayed_work(batadv_event_workqueue,
38 			   &bat_priv->orig_work, msecs_to_jiffies(1000));
39 }
40 
41 /* returns 1 if they are the same originator */
42 static int batadv_compare_orig(const struct hlist_node *node, const void *data2)
43 {
44 	const void *data1 = container_of(node, struct batadv_orig_node,
45 					 hash_entry);
46 
47 	return (memcmp(data1, data2, ETH_ALEN) == 0 ? 1 : 0);
48 }
49 
50 int batadv_originator_init(struct batadv_priv *bat_priv)
51 {
52 	if (bat_priv->orig_hash)
53 		return 0;
54 
55 	bat_priv->orig_hash = batadv_hash_new(1024);
56 
57 	if (!bat_priv->orig_hash)
58 		goto err;
59 
60 	batadv_start_purge_timer(bat_priv);
61 	return 0;
62 
63 err:
64 	return -ENOMEM;
65 }
66 
67 void batadv_neigh_node_free_ref(struct batadv_neigh_node *neigh_node)
68 {
69 	if (atomic_dec_and_test(&neigh_node->refcount))
70 		kfree_rcu(neigh_node, rcu);
71 }
72 
73 /* increases the refcounter of a found router */
74 struct batadv_neigh_node *
75 batadv_orig_node_get_router(struct batadv_orig_node *orig_node)
76 {
77 	struct batadv_neigh_node *router;
78 
79 	rcu_read_lock();
80 	router = rcu_dereference(orig_node->router);
81 
82 	if (router && !atomic_inc_not_zero(&router->refcount))
83 		router = NULL;
84 
85 	rcu_read_unlock();
86 	return router;
87 }
88 
89 struct batadv_neigh_node *
90 batadv_neigh_node_new(struct batadv_hard_iface *hard_iface,
91 		      const uint8_t *neigh_addr, uint32_t seqno)
92 {
93 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
94 	struct batadv_neigh_node *neigh_node;
95 
96 	neigh_node = kzalloc(sizeof(*neigh_node), GFP_ATOMIC);
97 	if (!neigh_node)
98 		goto out;
99 
100 	INIT_HLIST_NODE(&neigh_node->list);
101 
102 	memcpy(neigh_node->addr, neigh_addr, ETH_ALEN);
103 	spin_lock_init(&neigh_node->lq_update_lock);
104 
105 	/* extra reference for return */
106 	atomic_set(&neigh_node->refcount, 2);
107 
108 	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
109 		   "Creating new neighbor %pM, initial seqno %d\n",
110 		   neigh_addr, seqno);
111 
112 out:
113 	return neigh_node;
114 }
115 
116 static void batadv_orig_node_free_rcu(struct rcu_head *rcu)
117 {
118 	struct hlist_node *node, *node_tmp;
119 	struct batadv_neigh_node *neigh_node, *tmp_neigh_node;
120 	struct batadv_orig_node *orig_node;
121 
122 	orig_node = container_of(rcu, struct batadv_orig_node, rcu);
123 
124 	spin_lock_bh(&orig_node->neigh_list_lock);
125 
126 	/* for all bonding members ... */
127 	list_for_each_entry_safe(neigh_node, tmp_neigh_node,
128 				 &orig_node->bond_list, bonding_list) {
129 		list_del_rcu(&neigh_node->bonding_list);
130 		batadv_neigh_node_free_ref(neigh_node);
131 	}
132 
133 	/* for all neighbors towards this originator ... */
134 	hlist_for_each_entry_safe(neigh_node, node, node_tmp,
135 				  &orig_node->neigh_list, list) {
136 		hlist_del_rcu(&neigh_node->list);
137 		batadv_neigh_node_free_ref(neigh_node);
138 	}
139 
140 	spin_unlock_bh(&orig_node->neigh_list_lock);
141 
142 	batadv_frag_list_free(&orig_node->frag_list);
143 	batadv_tt_global_del_orig(orig_node->bat_priv, orig_node,
144 				  "originator timed out");
145 
146 	kfree(orig_node->tt_buff);
147 	kfree(orig_node->bcast_own);
148 	kfree(orig_node->bcast_own_sum);
149 	kfree(orig_node);
150 }
151 
152 void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node)
153 {
154 	if (atomic_dec_and_test(&orig_node->refcount))
155 		call_rcu(&orig_node->rcu, batadv_orig_node_free_rcu);
156 }
157 
158 void batadv_originator_free(struct batadv_priv *bat_priv)
159 {
160 	struct batadv_hashtable *hash = bat_priv->orig_hash;
161 	struct hlist_node *node, *node_tmp;
162 	struct hlist_head *head;
163 	spinlock_t *list_lock; /* spinlock to protect write access */
164 	struct batadv_orig_node *orig_node;
165 	uint32_t i;
166 
167 	if (!hash)
168 		return;
169 
170 	cancel_delayed_work_sync(&bat_priv->orig_work);
171 
172 	bat_priv->orig_hash = NULL;
173 
174 	for (i = 0; i < hash->size; i++) {
175 		head = &hash->table[i];
176 		list_lock = &hash->list_locks[i];
177 
178 		spin_lock_bh(list_lock);
179 		hlist_for_each_entry_safe(orig_node, node, node_tmp,
180 					  head, hash_entry) {
181 
182 			hlist_del_rcu(node);
183 			batadv_orig_node_free_ref(orig_node);
184 		}
185 		spin_unlock_bh(list_lock);
186 	}
187 
188 	batadv_hash_destroy(hash);
189 }
190 
191 /* this function finds or creates an originator entry for the given
192  * address if it does not exits
193  */
194 struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv,
195 					      const uint8_t *addr)
196 {
197 	struct batadv_orig_node *orig_node;
198 	int size;
199 	int hash_added;
200 	unsigned long reset_time;
201 
202 	orig_node = batadv_orig_hash_find(bat_priv, addr);
203 	if (orig_node)
204 		return orig_node;
205 
206 	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
207 		   "Creating new originator: %pM\n", addr);
208 
209 	orig_node = kzalloc(sizeof(*orig_node), GFP_ATOMIC);
210 	if (!orig_node)
211 		return NULL;
212 
213 	INIT_HLIST_HEAD(&orig_node->neigh_list);
214 	INIT_LIST_HEAD(&orig_node->bond_list);
215 	spin_lock_init(&orig_node->ogm_cnt_lock);
216 	spin_lock_init(&orig_node->bcast_seqno_lock);
217 	spin_lock_init(&orig_node->neigh_list_lock);
218 	spin_lock_init(&orig_node->tt_buff_lock);
219 
220 	/* extra reference for return */
221 	atomic_set(&orig_node->refcount, 2);
222 
223 	orig_node->tt_initialised = false;
224 	orig_node->bat_priv = bat_priv;
225 	memcpy(orig_node->orig, addr, ETH_ALEN);
226 	batadv_dat_init_orig_node_addr(orig_node);
227 	orig_node->router = NULL;
228 	orig_node->tt_crc = 0;
229 	atomic_set(&orig_node->last_ttvn, 0);
230 	orig_node->tt_buff = NULL;
231 	orig_node->tt_buff_len = 0;
232 	atomic_set(&orig_node->tt_size, 0);
233 	reset_time = jiffies - 1 - msecs_to_jiffies(BATADV_RESET_PROTECTION_MS);
234 	orig_node->bcast_seqno_reset = reset_time;
235 	orig_node->batman_seqno_reset = reset_time;
236 
237 	atomic_set(&orig_node->bond_candidates, 0);
238 
239 	size = bat_priv->num_ifaces * sizeof(unsigned long) * BATADV_NUM_WORDS;
240 
241 	orig_node->bcast_own = kzalloc(size, GFP_ATOMIC);
242 	if (!orig_node->bcast_own)
243 		goto free_orig_node;
244 
245 	size = bat_priv->num_ifaces * sizeof(uint8_t);
246 	orig_node->bcast_own_sum = kzalloc(size, GFP_ATOMIC);
247 
248 	INIT_LIST_HEAD(&orig_node->frag_list);
249 	orig_node->last_frag_packet = 0;
250 
251 	if (!orig_node->bcast_own_sum)
252 		goto free_bcast_own;
253 
254 	hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
255 				     batadv_choose_orig, orig_node,
256 				     &orig_node->hash_entry);
257 	if (hash_added != 0)
258 		goto free_bcast_own_sum;
259 
260 	return orig_node;
261 free_bcast_own_sum:
262 	kfree(orig_node->bcast_own_sum);
263 free_bcast_own:
264 	kfree(orig_node->bcast_own);
265 free_orig_node:
266 	kfree(orig_node);
267 	return NULL;
268 }
269 
270 static bool
271 batadv_purge_orig_neighbors(struct batadv_priv *bat_priv,
272 			    struct batadv_orig_node *orig_node,
273 			    struct batadv_neigh_node **best_neigh_node)
274 {
275 	struct hlist_node *node, *node_tmp;
276 	struct batadv_neigh_node *neigh_node;
277 	bool neigh_purged = false;
278 	unsigned long last_seen;
279 	struct batadv_hard_iface *if_incoming;
280 
281 	*best_neigh_node = NULL;
282 
283 	spin_lock_bh(&orig_node->neigh_list_lock);
284 
285 	/* for all neighbors towards this originator ... */
286 	hlist_for_each_entry_safe(neigh_node, node, node_tmp,
287 				  &orig_node->neigh_list, list) {
288 
289 		last_seen = neigh_node->last_seen;
290 		if_incoming = neigh_node->if_incoming;
291 
292 		if ((batadv_has_timed_out(last_seen, BATADV_PURGE_TIMEOUT)) ||
293 		    (if_incoming->if_status == BATADV_IF_INACTIVE) ||
294 		    (if_incoming->if_status == BATADV_IF_NOT_IN_USE) ||
295 		    (if_incoming->if_status == BATADV_IF_TO_BE_REMOVED)) {
296 
297 			if ((if_incoming->if_status == BATADV_IF_INACTIVE) ||
298 			    (if_incoming->if_status == BATADV_IF_NOT_IN_USE) ||
299 			    (if_incoming->if_status == BATADV_IF_TO_BE_REMOVED))
300 				batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
301 					   "neighbor purge: originator %pM, neighbor: %pM, iface: %s\n",
302 					   orig_node->orig, neigh_node->addr,
303 					   if_incoming->net_dev->name);
304 			else
305 				batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
306 					   "neighbor timeout: originator %pM, neighbor: %pM, last_seen: %u\n",
307 					   orig_node->orig, neigh_node->addr,
308 					   jiffies_to_msecs(last_seen));
309 
310 			neigh_purged = true;
311 
312 			hlist_del_rcu(&neigh_node->list);
313 			batadv_bonding_candidate_del(orig_node, neigh_node);
314 			batadv_neigh_node_free_ref(neigh_node);
315 		} else {
316 			if ((!*best_neigh_node) ||
317 			    (neigh_node->tq_avg > (*best_neigh_node)->tq_avg))
318 				*best_neigh_node = neigh_node;
319 		}
320 	}
321 
322 	spin_unlock_bh(&orig_node->neigh_list_lock);
323 	return neigh_purged;
324 }
325 
326 static bool batadv_purge_orig_node(struct batadv_priv *bat_priv,
327 				   struct batadv_orig_node *orig_node)
328 {
329 	struct batadv_neigh_node *best_neigh_node;
330 
331 	if (batadv_has_timed_out(orig_node->last_seen,
332 				 2 * BATADV_PURGE_TIMEOUT)) {
333 		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
334 			   "Originator timeout: originator %pM, last_seen %u\n",
335 			   orig_node->orig,
336 			   jiffies_to_msecs(orig_node->last_seen));
337 		return true;
338 	} else {
339 		if (batadv_purge_orig_neighbors(bat_priv, orig_node,
340 						&best_neigh_node))
341 			batadv_update_route(bat_priv, orig_node,
342 					    best_neigh_node);
343 	}
344 
345 	return false;
346 }
347 
348 static void _batadv_purge_orig(struct batadv_priv *bat_priv)
349 {
350 	struct batadv_hashtable *hash = bat_priv->orig_hash;
351 	struct hlist_node *node, *node_tmp;
352 	struct hlist_head *head;
353 	spinlock_t *list_lock; /* spinlock to protect write access */
354 	struct batadv_orig_node *orig_node;
355 	uint32_t i;
356 
357 	if (!hash)
358 		return;
359 
360 	/* for all origins... */
361 	for (i = 0; i < hash->size; i++) {
362 		head = &hash->table[i];
363 		list_lock = &hash->list_locks[i];
364 
365 		spin_lock_bh(list_lock);
366 		hlist_for_each_entry_safe(orig_node, node, node_tmp,
367 					  head, hash_entry) {
368 			if (batadv_purge_orig_node(bat_priv, orig_node)) {
369 				if (orig_node->gw_flags)
370 					batadv_gw_node_delete(bat_priv,
371 							      orig_node);
372 				hlist_del_rcu(node);
373 				batadv_orig_node_free_ref(orig_node);
374 				continue;
375 			}
376 
377 			if (batadv_has_timed_out(orig_node->last_frag_packet,
378 						 BATADV_FRAG_TIMEOUT))
379 				batadv_frag_list_free(&orig_node->frag_list);
380 		}
381 		spin_unlock_bh(list_lock);
382 	}
383 
384 	batadv_gw_node_purge(bat_priv);
385 	batadv_gw_election(bat_priv);
386 }
387 
388 static void batadv_purge_orig(struct work_struct *work)
389 {
390 	struct delayed_work *delayed_work;
391 	struct batadv_priv *bat_priv;
392 
393 	delayed_work = container_of(work, struct delayed_work, work);
394 	bat_priv = container_of(delayed_work, struct batadv_priv, orig_work);
395 	_batadv_purge_orig(bat_priv);
396 	batadv_start_purge_timer(bat_priv);
397 }
398 
399 void batadv_purge_orig_ref(struct batadv_priv *bat_priv)
400 {
401 	_batadv_purge_orig(bat_priv);
402 }
403 
404 int batadv_orig_seq_print_text(struct seq_file *seq, void *offset)
405 {
406 	struct net_device *net_dev = (struct net_device *)seq->private;
407 	struct batadv_priv *bat_priv = netdev_priv(net_dev);
408 	struct batadv_hashtable *hash = bat_priv->orig_hash;
409 	struct hlist_node *node, *node_tmp;
410 	struct hlist_head *head;
411 	struct batadv_hard_iface *primary_if;
412 	struct batadv_orig_node *orig_node;
413 	struct batadv_neigh_node *neigh_node, *neigh_node_tmp;
414 	int batman_count = 0;
415 	int last_seen_secs;
416 	int last_seen_msecs;
417 	unsigned long last_seen_jiffies;
418 	uint32_t i;
419 
420 	primary_if = batadv_seq_print_text_primary_if_get(seq);
421 	if (!primary_if)
422 		goto out;
423 
424 	seq_printf(seq, "[B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
425 		   BATADV_SOURCE_VERSION, primary_if->net_dev->name,
426 		   primary_if->net_dev->dev_addr, net_dev->name);
427 	seq_printf(seq, "  %-15s %s (%s/%i) %17s [%10s]: %20s ...\n",
428 		   "Originator", "last-seen", "#", BATADV_TQ_MAX_VALUE,
429 		   "Nexthop", "outgoingIF", "Potential nexthops");
430 
431 	for (i = 0; i < hash->size; i++) {
432 		head = &hash->table[i];
433 
434 		rcu_read_lock();
435 		hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
436 			neigh_node = batadv_orig_node_get_router(orig_node);
437 			if (!neigh_node)
438 				continue;
439 
440 			if (neigh_node->tq_avg == 0)
441 				goto next;
442 
443 			last_seen_jiffies = jiffies - orig_node->last_seen;
444 			last_seen_msecs = jiffies_to_msecs(last_seen_jiffies);
445 			last_seen_secs = last_seen_msecs / 1000;
446 			last_seen_msecs = last_seen_msecs % 1000;
447 
448 			seq_printf(seq, "%pM %4i.%03is   (%3i) %pM [%10s]:",
449 				   orig_node->orig, last_seen_secs,
450 				   last_seen_msecs, neigh_node->tq_avg,
451 				   neigh_node->addr,
452 				   neigh_node->if_incoming->net_dev->name);
453 
454 			hlist_for_each_entry_rcu(neigh_node_tmp, node_tmp,
455 						 &orig_node->neigh_list, list) {
456 				seq_printf(seq, " %pM (%3i)",
457 					   neigh_node_tmp->addr,
458 					   neigh_node_tmp->tq_avg);
459 			}
460 
461 			seq_printf(seq, "\n");
462 			batman_count++;
463 
464 next:
465 			batadv_neigh_node_free_ref(neigh_node);
466 		}
467 		rcu_read_unlock();
468 	}
469 
470 	if (batman_count == 0)
471 		seq_printf(seq, "No batman nodes in range ...\n");
472 
473 out:
474 	if (primary_if)
475 		batadv_hardif_free_ref(primary_if);
476 	return 0;
477 }
478 
479 static int batadv_orig_node_add_if(struct batadv_orig_node *orig_node,
480 				   int max_if_num)
481 {
482 	void *data_ptr;
483 	size_t data_size, old_size;
484 
485 	data_size = max_if_num * sizeof(unsigned long) * BATADV_NUM_WORDS;
486 	old_size = (max_if_num - 1) * sizeof(unsigned long) * BATADV_NUM_WORDS;
487 	data_ptr = kmalloc(data_size, GFP_ATOMIC);
488 	if (!data_ptr)
489 		return -ENOMEM;
490 
491 	memcpy(data_ptr, orig_node->bcast_own, old_size);
492 	kfree(orig_node->bcast_own);
493 	orig_node->bcast_own = data_ptr;
494 
495 	data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC);
496 	if (!data_ptr)
497 		return -ENOMEM;
498 
499 	memcpy(data_ptr, orig_node->bcast_own_sum,
500 	       (max_if_num - 1) * sizeof(uint8_t));
501 	kfree(orig_node->bcast_own_sum);
502 	orig_node->bcast_own_sum = data_ptr;
503 
504 	return 0;
505 }
506 
507 int batadv_orig_hash_add_if(struct batadv_hard_iface *hard_iface,
508 			    int max_if_num)
509 {
510 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
511 	struct batadv_hashtable *hash = bat_priv->orig_hash;
512 	struct hlist_node *node;
513 	struct hlist_head *head;
514 	struct batadv_orig_node *orig_node;
515 	uint32_t i;
516 	int ret;
517 
518 	/* resize all orig nodes because orig_node->bcast_own(_sum) depend on
519 	 * if_num
520 	 */
521 	for (i = 0; i < hash->size; i++) {
522 		head = &hash->table[i];
523 
524 		rcu_read_lock();
525 		hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
526 			spin_lock_bh(&orig_node->ogm_cnt_lock);
527 			ret = batadv_orig_node_add_if(orig_node, max_if_num);
528 			spin_unlock_bh(&orig_node->ogm_cnt_lock);
529 
530 			if (ret == -ENOMEM)
531 				goto err;
532 		}
533 		rcu_read_unlock();
534 	}
535 
536 	return 0;
537 
538 err:
539 	rcu_read_unlock();
540 	return -ENOMEM;
541 }
542 
543 static int batadv_orig_node_del_if(struct batadv_orig_node *orig_node,
544 				   int max_if_num, int del_if_num)
545 {
546 	void *data_ptr = NULL;
547 	int chunk_size;
548 
549 	/* last interface was removed */
550 	if (max_if_num == 0)
551 		goto free_bcast_own;
552 
553 	chunk_size = sizeof(unsigned long) * BATADV_NUM_WORDS;
554 	data_ptr = kmalloc(max_if_num * chunk_size, GFP_ATOMIC);
555 	if (!data_ptr)
556 		return -ENOMEM;
557 
558 	/* copy first part */
559 	memcpy(data_ptr, orig_node->bcast_own, del_if_num * chunk_size);
560 
561 	/* copy second part */
562 	memcpy((char *)data_ptr + del_if_num * chunk_size,
563 	       orig_node->bcast_own + ((del_if_num + 1) * chunk_size),
564 	       (max_if_num - del_if_num) * chunk_size);
565 
566 free_bcast_own:
567 	kfree(orig_node->bcast_own);
568 	orig_node->bcast_own = data_ptr;
569 
570 	if (max_if_num == 0)
571 		goto free_own_sum;
572 
573 	data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC);
574 	if (!data_ptr)
575 		return -ENOMEM;
576 
577 	memcpy(data_ptr, orig_node->bcast_own_sum,
578 	       del_if_num * sizeof(uint8_t));
579 
580 	memcpy((char *)data_ptr + del_if_num * sizeof(uint8_t),
581 	       orig_node->bcast_own_sum + ((del_if_num + 1) * sizeof(uint8_t)),
582 	       (max_if_num - del_if_num) * sizeof(uint8_t));
583 
584 free_own_sum:
585 	kfree(orig_node->bcast_own_sum);
586 	orig_node->bcast_own_sum = data_ptr;
587 
588 	return 0;
589 }
590 
591 int batadv_orig_hash_del_if(struct batadv_hard_iface *hard_iface,
592 			    int max_if_num)
593 {
594 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
595 	struct batadv_hashtable *hash = bat_priv->orig_hash;
596 	struct hlist_node *node;
597 	struct hlist_head *head;
598 	struct batadv_hard_iface *hard_iface_tmp;
599 	struct batadv_orig_node *orig_node;
600 	uint32_t i;
601 	int ret;
602 
603 	/* resize all orig nodes because orig_node->bcast_own(_sum) depend on
604 	 * if_num
605 	 */
606 	for (i = 0; i < hash->size; i++) {
607 		head = &hash->table[i];
608 
609 		rcu_read_lock();
610 		hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
611 			spin_lock_bh(&orig_node->ogm_cnt_lock);
612 			ret = batadv_orig_node_del_if(orig_node, max_if_num,
613 						      hard_iface->if_num);
614 			spin_unlock_bh(&orig_node->ogm_cnt_lock);
615 
616 			if (ret == -ENOMEM)
617 				goto err;
618 		}
619 		rcu_read_unlock();
620 	}
621 
622 	/* renumber remaining batman interfaces _inside_ of orig_hash_lock */
623 	rcu_read_lock();
624 	list_for_each_entry_rcu(hard_iface_tmp, &batadv_hardif_list, list) {
625 		if (hard_iface_tmp->if_status == BATADV_IF_NOT_IN_USE)
626 			continue;
627 
628 		if (hard_iface == hard_iface_tmp)
629 			continue;
630 
631 		if (hard_iface->soft_iface != hard_iface_tmp->soft_iface)
632 			continue;
633 
634 		if (hard_iface_tmp->if_num > hard_iface->if_num)
635 			hard_iface_tmp->if_num--;
636 	}
637 	rcu_read_unlock();
638 
639 	hard_iface->if_num = -1;
640 	return 0;
641 
642 err:
643 	rcu_read_unlock();
644 	return -ENOMEM;
645 }
646