1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) B.A.T.M.A.N. contributors:
3  *
4  * Simon Wunderlich
5  */
6 
7 #include "bridge_loop_avoidance.h"
8 #include "main.h"
9 
10 #include <linux/atomic.h>
11 #include <linux/byteorder/generic.h>
12 #include <linux/compiler.h>
13 #include <linux/container_of.h>
14 #include <linux/crc16.h>
15 #include <linux/errno.h>
16 #include <linux/etherdevice.h>
17 #include <linux/gfp.h>
18 #include <linux/if_arp.h>
19 #include <linux/if_ether.h>
20 #include <linux/if_vlan.h>
21 #include <linux/jhash.h>
22 #include <linux/jiffies.h>
23 #include <linux/kernel.h>
24 #include <linux/kref.h>
25 #include <linux/list.h>
26 #include <linux/lockdep.h>
27 #include <linux/netdevice.h>
28 #include <linux/netlink.h>
29 #include <linux/rculist.h>
30 #include <linux/rcupdate.h>
31 #include <linux/skbuff.h>
32 #include <linux/slab.h>
33 #include <linux/spinlock.h>
34 #include <linux/stddef.h>
35 #include <linux/string.h>
36 #include <linux/workqueue.h>
37 #include <net/arp.h>
38 #include <net/genetlink.h>
39 #include <net/netlink.h>
40 #include <net/sock.h>
41 #include <uapi/linux/batadv_packet.h>
42 #include <uapi/linux/batman_adv.h>
43 
44 #include "hard-interface.h"
45 #include "hash.h"
46 #include "log.h"
47 #include "netlink.h"
48 #include "originator.h"
49 #include "soft-interface.h"
50 #include "translation-table.h"
51 
52 static const u8 batadv_announce_mac[4] = {0x43, 0x05, 0x43, 0x05};
53 
54 static void batadv_bla_periodic_work(struct work_struct *work);
55 static void
56 batadv_bla_send_announce(struct batadv_priv *bat_priv,
57 			 struct batadv_bla_backbone_gw *backbone_gw);
58 
59 /**
60  * batadv_choose_claim() - choose the right bucket for a claim.
61  * @data: data to hash
62  * @size: size of the hash table
63  *
64  * Return: the hash index of the claim
65  */
66 static inline u32 batadv_choose_claim(const void *data, u32 size)
67 {
68 	const struct batadv_bla_claim *claim = data;
69 	u32 hash = 0;
70 
71 	hash = jhash(&claim->addr, sizeof(claim->addr), hash);
72 	hash = jhash(&claim->vid, sizeof(claim->vid), hash);
73 
74 	return hash % size;
75 }
76 
77 /**
78  * batadv_choose_backbone_gw() - choose the right bucket for a backbone gateway.
79  * @data: data to hash
80  * @size: size of the hash table
81  *
82  * Return: the hash index of the backbone gateway
83  */
84 static inline u32 batadv_choose_backbone_gw(const void *data, u32 size)
85 {
86 	const struct batadv_bla_backbone_gw *gw;
87 	u32 hash = 0;
88 
89 	gw = data;
90 	hash = jhash(&gw->orig, sizeof(gw->orig), hash);
91 	hash = jhash(&gw->vid, sizeof(gw->vid), hash);
92 
93 	return hash % size;
94 }
95 
96 /**
97  * batadv_compare_backbone_gw() - compare address and vid of two backbone gws
98  * @node: list node of the first entry to compare
99  * @data2: pointer to the second backbone gateway
100  *
101  * Return: true if the backbones have the same data, false otherwise
102  */
103 static bool batadv_compare_backbone_gw(const struct hlist_node *node,
104 				       const void *data2)
105 {
106 	const void *data1 = container_of(node, struct batadv_bla_backbone_gw,
107 					 hash_entry);
108 	const struct batadv_bla_backbone_gw *gw1 = data1;
109 	const struct batadv_bla_backbone_gw *gw2 = data2;
110 
111 	if (!batadv_compare_eth(gw1->orig, gw2->orig))
112 		return false;
113 
114 	if (gw1->vid != gw2->vid)
115 		return false;
116 
117 	return true;
118 }
119 
120 /**
121  * batadv_compare_claim() - compare address and vid of two claims
122  * @node: list node of the first entry to compare
123  * @data2: pointer to the second claims
124  *
125  * Return: true if the claim have the same data, 0 otherwise
126  */
127 static bool batadv_compare_claim(const struct hlist_node *node,
128 				 const void *data2)
129 {
130 	const void *data1 = container_of(node, struct batadv_bla_claim,
131 					 hash_entry);
132 	const struct batadv_bla_claim *cl1 = data1;
133 	const struct batadv_bla_claim *cl2 = data2;
134 
135 	if (!batadv_compare_eth(cl1->addr, cl2->addr))
136 		return false;
137 
138 	if (cl1->vid != cl2->vid)
139 		return false;
140 
141 	return true;
142 }
143 
144 /**
145  * batadv_backbone_gw_release() - release backbone gw from lists and queue for
146  *  free after rcu grace period
147  * @ref: kref pointer of the backbone gw
148  */
149 static void batadv_backbone_gw_release(struct kref *ref)
150 {
151 	struct batadv_bla_backbone_gw *backbone_gw;
152 
153 	backbone_gw = container_of(ref, struct batadv_bla_backbone_gw,
154 				   refcount);
155 
156 	kfree_rcu(backbone_gw, rcu);
157 }
158 
159 /**
160  * batadv_backbone_gw_put() - decrement the backbone gw refcounter and possibly
161  *  release it
162  * @backbone_gw: backbone gateway to be free'd
163  */
164 static void batadv_backbone_gw_put(struct batadv_bla_backbone_gw *backbone_gw)
165 {
166 	if (!backbone_gw)
167 		return;
168 
169 	kref_put(&backbone_gw->refcount, batadv_backbone_gw_release);
170 }
171 
172 /**
173  * batadv_claim_release() - release claim from lists and queue for free after
174  *  rcu grace period
175  * @ref: kref pointer of the claim
176  */
177 static void batadv_claim_release(struct kref *ref)
178 {
179 	struct batadv_bla_claim *claim;
180 	struct batadv_bla_backbone_gw *old_backbone_gw;
181 
182 	claim = container_of(ref, struct batadv_bla_claim, refcount);
183 
184 	spin_lock_bh(&claim->backbone_lock);
185 	old_backbone_gw = claim->backbone_gw;
186 	claim->backbone_gw = NULL;
187 	spin_unlock_bh(&claim->backbone_lock);
188 
189 	spin_lock_bh(&old_backbone_gw->crc_lock);
190 	old_backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
191 	spin_unlock_bh(&old_backbone_gw->crc_lock);
192 
193 	batadv_backbone_gw_put(old_backbone_gw);
194 
195 	kfree_rcu(claim, rcu);
196 }
197 
198 /**
199  * batadv_claim_put() - decrement the claim refcounter and possibly release it
200  * @claim: claim to be free'd
201  */
202 static void batadv_claim_put(struct batadv_bla_claim *claim)
203 {
204 	if (!claim)
205 		return;
206 
207 	kref_put(&claim->refcount, batadv_claim_release);
208 }
209 
210 /**
211  * batadv_claim_hash_find() - looks for a claim in the claim hash
212  * @bat_priv: the bat priv with all the soft interface information
213  * @data: search data (may be local/static data)
214  *
215  * Return: claim if found or NULL otherwise.
216  */
217 static struct batadv_bla_claim *
218 batadv_claim_hash_find(struct batadv_priv *bat_priv,
219 		       struct batadv_bla_claim *data)
220 {
221 	struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
222 	struct hlist_head *head;
223 	struct batadv_bla_claim *claim;
224 	struct batadv_bla_claim *claim_tmp = NULL;
225 	int index;
226 
227 	if (!hash)
228 		return NULL;
229 
230 	index = batadv_choose_claim(data, hash->size);
231 	head = &hash->table[index];
232 
233 	rcu_read_lock();
234 	hlist_for_each_entry_rcu(claim, head, hash_entry) {
235 		if (!batadv_compare_claim(&claim->hash_entry, data))
236 			continue;
237 
238 		if (!kref_get_unless_zero(&claim->refcount))
239 			continue;
240 
241 		claim_tmp = claim;
242 		break;
243 	}
244 	rcu_read_unlock();
245 
246 	return claim_tmp;
247 }
248 
249 /**
250  * batadv_backbone_hash_find() - looks for a backbone gateway in the hash
251  * @bat_priv: the bat priv with all the soft interface information
252  * @addr: the address of the originator
253  * @vid: the VLAN ID
254  *
255  * Return: backbone gateway if found or NULL otherwise
256  */
257 static struct batadv_bla_backbone_gw *
258 batadv_backbone_hash_find(struct batadv_priv *bat_priv, const u8 *addr,
259 			  unsigned short vid)
260 {
261 	struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
262 	struct hlist_head *head;
263 	struct batadv_bla_backbone_gw search_entry, *backbone_gw;
264 	struct batadv_bla_backbone_gw *backbone_gw_tmp = NULL;
265 	int index;
266 
267 	if (!hash)
268 		return NULL;
269 
270 	ether_addr_copy(search_entry.orig, addr);
271 	search_entry.vid = vid;
272 
273 	index = batadv_choose_backbone_gw(&search_entry, hash->size);
274 	head = &hash->table[index];
275 
276 	rcu_read_lock();
277 	hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
278 		if (!batadv_compare_backbone_gw(&backbone_gw->hash_entry,
279 						&search_entry))
280 			continue;
281 
282 		if (!kref_get_unless_zero(&backbone_gw->refcount))
283 			continue;
284 
285 		backbone_gw_tmp = backbone_gw;
286 		break;
287 	}
288 	rcu_read_unlock();
289 
290 	return backbone_gw_tmp;
291 }
292 
293 /**
294  * batadv_bla_del_backbone_claims() - delete all claims for a backbone
295  * @backbone_gw: backbone gateway where the claims should be removed
296  */
297 static void
298 batadv_bla_del_backbone_claims(struct batadv_bla_backbone_gw *backbone_gw)
299 {
300 	struct batadv_hashtable *hash;
301 	struct hlist_node *node_tmp;
302 	struct hlist_head *head;
303 	struct batadv_bla_claim *claim;
304 	int i;
305 	spinlock_t *list_lock;	/* protects write access to the hash lists */
306 
307 	hash = backbone_gw->bat_priv->bla.claim_hash;
308 	if (!hash)
309 		return;
310 
311 	for (i = 0; i < hash->size; i++) {
312 		head = &hash->table[i];
313 		list_lock = &hash->list_locks[i];
314 
315 		spin_lock_bh(list_lock);
316 		hlist_for_each_entry_safe(claim, node_tmp,
317 					  head, hash_entry) {
318 			if (claim->backbone_gw != backbone_gw)
319 				continue;
320 
321 			batadv_claim_put(claim);
322 			hlist_del_rcu(&claim->hash_entry);
323 		}
324 		spin_unlock_bh(list_lock);
325 	}
326 
327 	/* all claims gone, initialize CRC */
328 	spin_lock_bh(&backbone_gw->crc_lock);
329 	backbone_gw->crc = BATADV_BLA_CRC_INIT;
330 	spin_unlock_bh(&backbone_gw->crc_lock);
331 }
332 
333 /**
334  * batadv_bla_send_claim() - sends a claim frame according to the provided info
335  * @bat_priv: the bat priv with all the soft interface information
336  * @mac: the mac address to be announced within the claim
337  * @vid: the VLAN ID
338  * @claimtype: the type of the claim (CLAIM, UNCLAIM, ANNOUNCE, ...)
339  */
340 static void batadv_bla_send_claim(struct batadv_priv *bat_priv, const u8 *mac,
341 				  unsigned short vid, int claimtype)
342 {
343 	struct sk_buff *skb;
344 	struct ethhdr *ethhdr;
345 	struct batadv_hard_iface *primary_if;
346 	struct net_device *soft_iface;
347 	u8 *hw_src;
348 	struct batadv_bla_claim_dst local_claim_dest;
349 	__be32 zeroip = 0;
350 
351 	primary_if = batadv_primary_if_get_selected(bat_priv);
352 	if (!primary_if)
353 		return;
354 
355 	memcpy(&local_claim_dest, &bat_priv->bla.claim_dest,
356 	       sizeof(local_claim_dest));
357 	local_claim_dest.type = claimtype;
358 
359 	soft_iface = primary_if->soft_iface;
360 
361 	skb = arp_create(ARPOP_REPLY, ETH_P_ARP,
362 			 /* IP DST: 0.0.0.0 */
363 			 zeroip,
364 			 primary_if->soft_iface,
365 			 /* IP SRC: 0.0.0.0 */
366 			 zeroip,
367 			 /* Ethernet DST: Broadcast */
368 			 NULL,
369 			 /* Ethernet SRC/HW SRC:  originator mac */
370 			 primary_if->net_dev->dev_addr,
371 			 /* HW DST: FF:43:05:XX:YY:YY
372 			  * with XX   = claim type
373 			  * and YY:YY = group id
374 			  */
375 			 (u8 *)&local_claim_dest);
376 
377 	if (!skb)
378 		goto out;
379 
380 	ethhdr = (struct ethhdr *)skb->data;
381 	hw_src = (u8 *)ethhdr + ETH_HLEN + sizeof(struct arphdr);
382 
383 	/* now we pretend that the client would have sent this ... */
384 	switch (claimtype) {
385 	case BATADV_CLAIM_TYPE_CLAIM:
386 		/* normal claim frame
387 		 * set Ethernet SRC to the clients mac
388 		 */
389 		ether_addr_copy(ethhdr->h_source, mac);
390 		batadv_dbg(BATADV_DBG_BLA, bat_priv,
391 			   "%s(): CLAIM %pM on vid %d\n", __func__, mac,
392 			   batadv_print_vid(vid));
393 		break;
394 	case BATADV_CLAIM_TYPE_UNCLAIM:
395 		/* unclaim frame
396 		 * set HW SRC to the clients mac
397 		 */
398 		ether_addr_copy(hw_src, mac);
399 		batadv_dbg(BATADV_DBG_BLA, bat_priv,
400 			   "%s(): UNCLAIM %pM on vid %d\n", __func__, mac,
401 			   batadv_print_vid(vid));
402 		break;
403 	case BATADV_CLAIM_TYPE_ANNOUNCE:
404 		/* announcement frame
405 		 * set HW SRC to the special mac containing the crc
406 		 */
407 		ether_addr_copy(hw_src, mac);
408 		batadv_dbg(BATADV_DBG_BLA, bat_priv,
409 			   "%s(): ANNOUNCE of %pM on vid %d\n", __func__,
410 			   ethhdr->h_source, batadv_print_vid(vid));
411 		break;
412 	case BATADV_CLAIM_TYPE_REQUEST:
413 		/* request frame
414 		 * set HW SRC and header destination to the receiving backbone
415 		 * gws mac
416 		 */
417 		ether_addr_copy(hw_src, mac);
418 		ether_addr_copy(ethhdr->h_dest, mac);
419 		batadv_dbg(BATADV_DBG_BLA, bat_priv,
420 			   "%s(): REQUEST of %pM to %pM on vid %d\n", __func__,
421 			   ethhdr->h_source, ethhdr->h_dest,
422 			   batadv_print_vid(vid));
423 		break;
424 	case BATADV_CLAIM_TYPE_LOOPDETECT:
425 		ether_addr_copy(ethhdr->h_source, mac);
426 		batadv_dbg(BATADV_DBG_BLA, bat_priv,
427 			   "%s(): LOOPDETECT of %pM to %pM on vid %d\n",
428 			   __func__, ethhdr->h_source, ethhdr->h_dest,
429 			   batadv_print_vid(vid));
430 
431 		break;
432 	}
433 
434 	if (vid & BATADV_VLAN_HAS_TAG) {
435 		skb = vlan_insert_tag(skb, htons(ETH_P_8021Q),
436 				      vid & VLAN_VID_MASK);
437 		if (!skb)
438 			goto out;
439 	}
440 
441 	skb_reset_mac_header(skb);
442 	skb->protocol = eth_type_trans(skb, soft_iface);
443 	batadv_inc_counter(bat_priv, BATADV_CNT_RX);
444 	batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
445 			   skb->len + ETH_HLEN);
446 
447 	netif_rx(skb);
448 out:
449 	batadv_hardif_put(primary_if);
450 }
451 
452 /**
453  * batadv_bla_loopdetect_report() - worker for reporting the loop
454  * @work: work queue item
455  *
456  * Throws an uevent, as the loopdetect check function can't do that itself
457  * since the kernel may sleep while throwing uevents.
458  */
459 static void batadv_bla_loopdetect_report(struct work_struct *work)
460 {
461 	struct batadv_bla_backbone_gw *backbone_gw;
462 	struct batadv_priv *bat_priv;
463 	char vid_str[6] = { '\0' };
464 
465 	backbone_gw = container_of(work, struct batadv_bla_backbone_gw,
466 				   report_work);
467 	bat_priv = backbone_gw->bat_priv;
468 
469 	batadv_info(bat_priv->soft_iface,
470 		    "Possible loop on VLAN %d detected which can't be handled by BLA - please check your network setup!\n",
471 		    batadv_print_vid(backbone_gw->vid));
472 	snprintf(vid_str, sizeof(vid_str), "%d",
473 		 batadv_print_vid(backbone_gw->vid));
474 	vid_str[sizeof(vid_str) - 1] = 0;
475 
476 	batadv_throw_uevent(bat_priv, BATADV_UEV_BLA, BATADV_UEV_LOOPDETECT,
477 			    vid_str);
478 
479 	batadv_backbone_gw_put(backbone_gw);
480 }
481 
482 /**
483  * batadv_bla_get_backbone_gw() - finds or creates a backbone gateway
484  * @bat_priv: the bat priv with all the soft interface information
485  * @orig: the mac address of the originator
486  * @vid: the VLAN ID
487  * @own_backbone: set if the requested backbone is local
488  *
489  * Return: the (possibly created) backbone gateway or NULL on error
490  */
491 static struct batadv_bla_backbone_gw *
492 batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, const u8 *orig,
493 			   unsigned short vid, bool own_backbone)
494 {
495 	struct batadv_bla_backbone_gw *entry;
496 	struct batadv_orig_node *orig_node;
497 	int hash_added;
498 
499 	entry = batadv_backbone_hash_find(bat_priv, orig, vid);
500 
501 	if (entry)
502 		return entry;
503 
504 	batadv_dbg(BATADV_DBG_BLA, bat_priv,
505 		   "%s(): not found (%pM, %d), creating new entry\n", __func__,
506 		   orig, batadv_print_vid(vid));
507 
508 	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
509 	if (!entry)
510 		return NULL;
511 
512 	entry->vid = vid;
513 	entry->lasttime = jiffies;
514 	entry->crc = BATADV_BLA_CRC_INIT;
515 	entry->bat_priv = bat_priv;
516 	spin_lock_init(&entry->crc_lock);
517 	atomic_set(&entry->request_sent, 0);
518 	atomic_set(&entry->wait_periods, 0);
519 	ether_addr_copy(entry->orig, orig);
520 	INIT_WORK(&entry->report_work, batadv_bla_loopdetect_report);
521 	kref_init(&entry->refcount);
522 
523 	kref_get(&entry->refcount);
524 	hash_added = batadv_hash_add(bat_priv->bla.backbone_hash,
525 				     batadv_compare_backbone_gw,
526 				     batadv_choose_backbone_gw, entry,
527 				     &entry->hash_entry);
528 
529 	if (unlikely(hash_added != 0)) {
530 		/* hash failed, free the structure */
531 		kfree(entry);
532 		return NULL;
533 	}
534 
535 	/* this is a gateway now, remove any TT entry on this VLAN */
536 	orig_node = batadv_orig_hash_find(bat_priv, orig);
537 	if (orig_node) {
538 		batadv_tt_global_del_orig(bat_priv, orig_node, vid,
539 					  "became a backbone gateway");
540 		batadv_orig_node_put(orig_node);
541 	}
542 
543 	if (own_backbone) {
544 		batadv_bla_send_announce(bat_priv, entry);
545 
546 		/* this will be decreased in the worker thread */
547 		atomic_inc(&entry->request_sent);
548 		atomic_set(&entry->wait_periods, BATADV_BLA_WAIT_PERIODS);
549 		atomic_inc(&bat_priv->bla.num_requests);
550 	}
551 
552 	return entry;
553 }
554 
555 /**
556  * batadv_bla_update_own_backbone_gw() - updates the own backbone gw for a VLAN
557  * @bat_priv: the bat priv with all the soft interface information
558  * @primary_if: the selected primary interface
559  * @vid: VLAN identifier
560  *
561  * update or add the own backbone gw to make sure we announce
562  * where we receive other backbone gws
563  */
564 static void
565 batadv_bla_update_own_backbone_gw(struct batadv_priv *bat_priv,
566 				  struct batadv_hard_iface *primary_if,
567 				  unsigned short vid)
568 {
569 	struct batadv_bla_backbone_gw *backbone_gw;
570 
571 	backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
572 						 primary_if->net_dev->dev_addr,
573 						 vid, true);
574 	if (unlikely(!backbone_gw))
575 		return;
576 
577 	backbone_gw->lasttime = jiffies;
578 	batadv_backbone_gw_put(backbone_gw);
579 }
580 
581 /**
582  * batadv_bla_answer_request() - answer a bla request by sending own claims
583  * @bat_priv: the bat priv with all the soft interface information
584  * @primary_if: interface where the request came on
585  * @vid: the vid where the request came on
586  *
587  * Repeat all of our own claims, and finally send an ANNOUNCE frame
588  * to allow the requester another check if the CRC is correct now.
589  */
590 static void batadv_bla_answer_request(struct batadv_priv *bat_priv,
591 				      struct batadv_hard_iface *primary_if,
592 				      unsigned short vid)
593 {
594 	struct hlist_head *head;
595 	struct batadv_hashtable *hash;
596 	struct batadv_bla_claim *claim;
597 	struct batadv_bla_backbone_gw *backbone_gw;
598 	int i;
599 
600 	batadv_dbg(BATADV_DBG_BLA, bat_priv,
601 		   "%s(): received a claim request, send all of our own claims again\n",
602 		   __func__);
603 
604 	backbone_gw = batadv_backbone_hash_find(bat_priv,
605 						primary_if->net_dev->dev_addr,
606 						vid);
607 	if (!backbone_gw)
608 		return;
609 
610 	hash = bat_priv->bla.claim_hash;
611 	for (i = 0; i < hash->size; i++) {
612 		head = &hash->table[i];
613 
614 		rcu_read_lock();
615 		hlist_for_each_entry_rcu(claim, head, hash_entry) {
616 			/* only own claims are interesting */
617 			if (claim->backbone_gw != backbone_gw)
618 				continue;
619 
620 			batadv_bla_send_claim(bat_priv, claim->addr, claim->vid,
621 					      BATADV_CLAIM_TYPE_CLAIM);
622 		}
623 		rcu_read_unlock();
624 	}
625 
626 	/* finally, send an announcement frame */
627 	batadv_bla_send_announce(bat_priv, backbone_gw);
628 	batadv_backbone_gw_put(backbone_gw);
629 }
630 
631 /**
632  * batadv_bla_send_request() - send a request to repeat claims
633  * @backbone_gw: the backbone gateway from whom we are out of sync
634  *
635  * When the crc is wrong, ask the backbone gateway for a full table update.
636  * After the request, it will repeat all of his own claims and finally
637  * send an announcement claim with which we can check again.
638  */
639 static void batadv_bla_send_request(struct batadv_bla_backbone_gw *backbone_gw)
640 {
641 	/* first, remove all old entries */
642 	batadv_bla_del_backbone_claims(backbone_gw);
643 
644 	batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
645 		   "Sending REQUEST to %pM\n", backbone_gw->orig);
646 
647 	/* send request */
648 	batadv_bla_send_claim(backbone_gw->bat_priv, backbone_gw->orig,
649 			      backbone_gw->vid, BATADV_CLAIM_TYPE_REQUEST);
650 
651 	/* no local broadcasts should be sent or received, for now. */
652 	if (!atomic_read(&backbone_gw->request_sent)) {
653 		atomic_inc(&backbone_gw->bat_priv->bla.num_requests);
654 		atomic_set(&backbone_gw->request_sent, 1);
655 	}
656 }
657 
658 /**
659  * batadv_bla_send_announce() - Send an announcement frame
660  * @bat_priv: the bat priv with all the soft interface information
661  * @backbone_gw: our backbone gateway which should be announced
662  */
663 static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
664 				     struct batadv_bla_backbone_gw *backbone_gw)
665 {
666 	u8 mac[ETH_ALEN];
667 	__be16 crc;
668 
669 	memcpy(mac, batadv_announce_mac, 4);
670 	spin_lock_bh(&backbone_gw->crc_lock);
671 	crc = htons(backbone_gw->crc);
672 	spin_unlock_bh(&backbone_gw->crc_lock);
673 	memcpy(&mac[4], &crc, 2);
674 
675 	batadv_bla_send_claim(bat_priv, mac, backbone_gw->vid,
676 			      BATADV_CLAIM_TYPE_ANNOUNCE);
677 }
678 
679 /**
680  * batadv_bla_add_claim() - Adds a claim in the claim hash
681  * @bat_priv: the bat priv with all the soft interface information
682  * @mac: the mac address of the claim
683  * @vid: the VLAN ID of the frame
684  * @backbone_gw: the backbone gateway which claims it
685  */
686 static void batadv_bla_add_claim(struct batadv_priv *bat_priv,
687 				 const u8 *mac, const unsigned short vid,
688 				 struct batadv_bla_backbone_gw *backbone_gw)
689 {
690 	struct batadv_bla_backbone_gw *old_backbone_gw;
691 	struct batadv_bla_claim *claim;
692 	struct batadv_bla_claim search_claim;
693 	bool remove_crc = false;
694 	int hash_added;
695 
696 	ether_addr_copy(search_claim.addr, mac);
697 	search_claim.vid = vid;
698 	claim = batadv_claim_hash_find(bat_priv, &search_claim);
699 
700 	/* create a new claim entry if it does not exist yet. */
701 	if (!claim) {
702 		claim = kzalloc(sizeof(*claim), GFP_ATOMIC);
703 		if (!claim)
704 			return;
705 
706 		ether_addr_copy(claim->addr, mac);
707 		spin_lock_init(&claim->backbone_lock);
708 		claim->vid = vid;
709 		claim->lasttime = jiffies;
710 		kref_get(&backbone_gw->refcount);
711 		claim->backbone_gw = backbone_gw;
712 		kref_init(&claim->refcount);
713 
714 		batadv_dbg(BATADV_DBG_BLA, bat_priv,
715 			   "%s(): adding new entry %pM, vid %d to hash ...\n",
716 			   __func__, mac, batadv_print_vid(vid));
717 
718 		kref_get(&claim->refcount);
719 		hash_added = batadv_hash_add(bat_priv->bla.claim_hash,
720 					     batadv_compare_claim,
721 					     batadv_choose_claim, claim,
722 					     &claim->hash_entry);
723 
724 		if (unlikely(hash_added != 0)) {
725 			/* only local changes happened. */
726 			kfree(claim);
727 			return;
728 		}
729 	} else {
730 		claim->lasttime = jiffies;
731 		if (claim->backbone_gw == backbone_gw)
732 			/* no need to register a new backbone */
733 			goto claim_free_ref;
734 
735 		batadv_dbg(BATADV_DBG_BLA, bat_priv,
736 			   "%s(): changing ownership for %pM, vid %d to gw %pM\n",
737 			   __func__, mac, batadv_print_vid(vid),
738 			   backbone_gw->orig);
739 
740 		remove_crc = true;
741 	}
742 
743 	/* replace backbone_gw atomically and adjust reference counters */
744 	spin_lock_bh(&claim->backbone_lock);
745 	old_backbone_gw = claim->backbone_gw;
746 	kref_get(&backbone_gw->refcount);
747 	claim->backbone_gw = backbone_gw;
748 	spin_unlock_bh(&claim->backbone_lock);
749 
750 	if (remove_crc) {
751 		/* remove claim address from old backbone_gw */
752 		spin_lock_bh(&old_backbone_gw->crc_lock);
753 		old_backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
754 		spin_unlock_bh(&old_backbone_gw->crc_lock);
755 	}
756 
757 	batadv_backbone_gw_put(old_backbone_gw);
758 
759 	/* add claim address to new backbone_gw */
760 	spin_lock_bh(&backbone_gw->crc_lock);
761 	backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
762 	spin_unlock_bh(&backbone_gw->crc_lock);
763 	backbone_gw->lasttime = jiffies;
764 
765 claim_free_ref:
766 	batadv_claim_put(claim);
767 }
768 
769 /**
770  * batadv_bla_claim_get_backbone_gw() - Get valid reference for backbone_gw of
771  *  claim
772  * @claim: claim whose backbone_gw should be returned
773  *
774  * Return: valid reference to claim::backbone_gw
775  */
776 static struct batadv_bla_backbone_gw *
777 batadv_bla_claim_get_backbone_gw(struct batadv_bla_claim *claim)
778 {
779 	struct batadv_bla_backbone_gw *backbone_gw;
780 
781 	spin_lock_bh(&claim->backbone_lock);
782 	backbone_gw = claim->backbone_gw;
783 	kref_get(&backbone_gw->refcount);
784 	spin_unlock_bh(&claim->backbone_lock);
785 
786 	return backbone_gw;
787 }
788 
789 /**
790  * batadv_bla_del_claim() - delete a claim from the claim hash
791  * @bat_priv: the bat priv with all the soft interface information
792  * @mac: mac address of the claim to be removed
793  * @vid: VLAN id for the claim to be removed
794  */
795 static void batadv_bla_del_claim(struct batadv_priv *bat_priv,
796 				 const u8 *mac, const unsigned short vid)
797 {
798 	struct batadv_bla_claim search_claim, *claim;
799 	struct batadv_bla_claim *claim_removed_entry;
800 	struct hlist_node *claim_removed_node;
801 
802 	ether_addr_copy(search_claim.addr, mac);
803 	search_claim.vid = vid;
804 	claim = batadv_claim_hash_find(bat_priv, &search_claim);
805 	if (!claim)
806 		return;
807 
808 	batadv_dbg(BATADV_DBG_BLA, bat_priv, "%s(): %pM, vid %d\n", __func__,
809 		   mac, batadv_print_vid(vid));
810 
811 	claim_removed_node = batadv_hash_remove(bat_priv->bla.claim_hash,
812 						batadv_compare_claim,
813 						batadv_choose_claim, claim);
814 	if (!claim_removed_node)
815 		goto free_claim;
816 
817 	/* reference from the hash is gone */
818 	claim_removed_entry = hlist_entry(claim_removed_node,
819 					  struct batadv_bla_claim, hash_entry);
820 	batadv_claim_put(claim_removed_entry);
821 
822 free_claim:
823 	/* don't need the reference from hash_find() anymore */
824 	batadv_claim_put(claim);
825 }
826 
827 /**
828  * batadv_handle_announce() - check for ANNOUNCE frame
829  * @bat_priv: the bat priv with all the soft interface information
830  * @an_addr: announcement mac address (ARP Sender HW address)
831  * @backbone_addr: originator address of the sender (Ethernet source MAC)
832  * @vid: the VLAN ID of the frame
833  *
834  * Return: true if handled
835  */
836 static bool batadv_handle_announce(struct batadv_priv *bat_priv, u8 *an_addr,
837 				   u8 *backbone_addr, unsigned short vid)
838 {
839 	struct batadv_bla_backbone_gw *backbone_gw;
840 	u16 backbone_crc, crc;
841 
842 	if (memcmp(an_addr, batadv_announce_mac, 4) != 0)
843 		return false;
844 
845 	backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
846 						 false);
847 
848 	if (unlikely(!backbone_gw))
849 		return true;
850 
851 	/* handle as ANNOUNCE frame */
852 	backbone_gw->lasttime = jiffies;
853 	crc = ntohs(*((__force __be16 *)(&an_addr[4])));
854 
855 	batadv_dbg(BATADV_DBG_BLA, bat_priv,
856 		   "%s(): ANNOUNCE vid %d (sent by %pM)... CRC = %#.4x\n",
857 		   __func__, batadv_print_vid(vid), backbone_gw->orig, crc);
858 
859 	spin_lock_bh(&backbone_gw->crc_lock);
860 	backbone_crc = backbone_gw->crc;
861 	spin_unlock_bh(&backbone_gw->crc_lock);
862 
863 	if (backbone_crc != crc) {
864 		batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
865 			   "%s(): CRC FAILED for %pM/%d (my = %#.4x, sent = %#.4x)\n",
866 			   __func__, backbone_gw->orig,
867 			   batadv_print_vid(backbone_gw->vid),
868 			   backbone_crc, crc);
869 
870 		batadv_bla_send_request(backbone_gw);
871 	} else {
872 		/* if we have sent a request and the crc was OK,
873 		 * we can allow traffic again.
874 		 */
875 		if (atomic_read(&backbone_gw->request_sent)) {
876 			atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
877 			atomic_set(&backbone_gw->request_sent, 0);
878 		}
879 	}
880 
881 	batadv_backbone_gw_put(backbone_gw);
882 	return true;
883 }
884 
885 /**
886  * batadv_handle_request() - check for REQUEST frame
887  * @bat_priv: the bat priv with all the soft interface information
888  * @primary_if: the primary hard interface of this batman soft interface
889  * @backbone_addr: backbone address to be requested (ARP sender HW MAC)
890  * @ethhdr: ethernet header of a packet
891  * @vid: the VLAN ID of the frame
892  *
893  * Return: true if handled
894  */
895 static bool batadv_handle_request(struct batadv_priv *bat_priv,
896 				  struct batadv_hard_iface *primary_if,
897 				  u8 *backbone_addr, struct ethhdr *ethhdr,
898 				  unsigned short vid)
899 {
900 	/* check for REQUEST frame */
901 	if (!batadv_compare_eth(backbone_addr, ethhdr->h_dest))
902 		return false;
903 
904 	/* sanity check, this should not happen on a normal switch,
905 	 * we ignore it in this case.
906 	 */
907 	if (!batadv_compare_eth(ethhdr->h_dest, primary_if->net_dev->dev_addr))
908 		return true;
909 
910 	batadv_dbg(BATADV_DBG_BLA, bat_priv,
911 		   "%s(): REQUEST vid %d (sent by %pM)...\n",
912 		   __func__, batadv_print_vid(vid), ethhdr->h_source);
913 
914 	batadv_bla_answer_request(bat_priv, primary_if, vid);
915 	return true;
916 }
917 
918 /**
919  * batadv_handle_unclaim() - check for UNCLAIM frame
920  * @bat_priv: the bat priv with all the soft interface information
921  * @primary_if: the primary hard interface of this batman soft interface
922  * @backbone_addr: originator address of the backbone (Ethernet source)
923  * @claim_addr: Client to be unclaimed (ARP sender HW MAC)
924  * @vid: the VLAN ID of the frame
925  *
926  * Return: true if handled
927  */
928 static bool batadv_handle_unclaim(struct batadv_priv *bat_priv,
929 				  struct batadv_hard_iface *primary_if,
930 				  const u8 *backbone_addr, const u8 *claim_addr,
931 				  unsigned short vid)
932 {
933 	struct batadv_bla_backbone_gw *backbone_gw;
934 
935 	/* unclaim in any case if it is our own */
936 	if (primary_if && batadv_compare_eth(backbone_addr,
937 					     primary_if->net_dev->dev_addr))
938 		batadv_bla_send_claim(bat_priv, claim_addr, vid,
939 				      BATADV_CLAIM_TYPE_UNCLAIM);
940 
941 	backbone_gw = batadv_backbone_hash_find(bat_priv, backbone_addr, vid);
942 
943 	if (!backbone_gw)
944 		return true;
945 
946 	/* this must be an UNCLAIM frame */
947 	batadv_dbg(BATADV_DBG_BLA, bat_priv,
948 		   "%s(): UNCLAIM %pM on vid %d (sent by %pM)...\n", __func__,
949 		   claim_addr, batadv_print_vid(vid), backbone_gw->orig);
950 
951 	batadv_bla_del_claim(bat_priv, claim_addr, vid);
952 	batadv_backbone_gw_put(backbone_gw);
953 	return true;
954 }
955 
956 /**
957  * batadv_handle_claim() - check for CLAIM frame
958  * @bat_priv: the bat priv with all the soft interface information
959  * @primary_if: the primary hard interface of this batman soft interface
960  * @backbone_addr: originator address of the backbone (Ethernet Source)
961  * @claim_addr: client mac address to be claimed (ARP sender HW MAC)
962  * @vid: the VLAN ID of the frame
963  *
964  * Return: true if handled
965  */
966 static bool batadv_handle_claim(struct batadv_priv *bat_priv,
967 				struct batadv_hard_iface *primary_if,
968 				const u8 *backbone_addr, const u8 *claim_addr,
969 				unsigned short vid)
970 {
971 	struct batadv_bla_backbone_gw *backbone_gw;
972 
973 	/* register the gateway if not yet available, and add the claim. */
974 
975 	backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
976 						 false);
977 
978 	if (unlikely(!backbone_gw))
979 		return true;
980 
981 	/* this must be a CLAIM frame */
982 	batadv_bla_add_claim(bat_priv, claim_addr, vid, backbone_gw);
983 	if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
984 		batadv_bla_send_claim(bat_priv, claim_addr, vid,
985 				      BATADV_CLAIM_TYPE_CLAIM);
986 
987 	/* TODO: we could call something like tt_local_del() here. */
988 
989 	batadv_backbone_gw_put(backbone_gw);
990 	return true;
991 }
992 
993 /**
994  * batadv_check_claim_group() - check for claim group membership
995  * @bat_priv: the bat priv with all the soft interface information
996  * @primary_if: the primary interface of this batman interface
997  * @hw_src: the Hardware source in the ARP Header
998  * @hw_dst: the Hardware destination in the ARP Header
999  * @ethhdr: pointer to the Ethernet header of the claim frame
1000  *
1001  * checks if it is a claim packet and if it's on the same group.
1002  * This function also applies the group ID of the sender
1003  * if it is in the same mesh.
1004  *
1005  * Return:
1006  *	2  - if it is a claim packet and on the same group
1007  *	1  - if is a claim packet from another group
1008  *	0  - if it is not a claim packet
1009  */
1010 static int batadv_check_claim_group(struct batadv_priv *bat_priv,
1011 				    struct batadv_hard_iface *primary_if,
1012 				    u8 *hw_src, u8 *hw_dst,
1013 				    struct ethhdr *ethhdr)
1014 {
1015 	u8 *backbone_addr;
1016 	struct batadv_orig_node *orig_node;
1017 	struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
1018 
1019 	bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
1020 	bla_dst_own = &bat_priv->bla.claim_dest;
1021 
1022 	/* if announcement packet, use the source,
1023 	 * otherwise assume it is in the hw_src
1024 	 */
1025 	switch (bla_dst->type) {
1026 	case BATADV_CLAIM_TYPE_CLAIM:
1027 		backbone_addr = hw_src;
1028 		break;
1029 	case BATADV_CLAIM_TYPE_REQUEST:
1030 	case BATADV_CLAIM_TYPE_ANNOUNCE:
1031 	case BATADV_CLAIM_TYPE_UNCLAIM:
1032 		backbone_addr = ethhdr->h_source;
1033 		break;
1034 	default:
1035 		return 0;
1036 	}
1037 
1038 	/* don't accept claim frames from ourselves */
1039 	if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
1040 		return 0;
1041 
1042 	/* if its already the same group, it is fine. */
1043 	if (bla_dst->group == bla_dst_own->group)
1044 		return 2;
1045 
1046 	/* lets see if this originator is in our mesh */
1047 	orig_node = batadv_orig_hash_find(bat_priv, backbone_addr);
1048 
1049 	/* don't accept claims from gateways which are not in
1050 	 * the same mesh or group.
1051 	 */
1052 	if (!orig_node)
1053 		return 1;
1054 
1055 	/* if our mesh friends mac is bigger, use it for ourselves. */
1056 	if (ntohs(bla_dst->group) > ntohs(bla_dst_own->group)) {
1057 		batadv_dbg(BATADV_DBG_BLA, bat_priv,
1058 			   "taking other backbones claim group: %#.4x\n",
1059 			   ntohs(bla_dst->group));
1060 		bla_dst_own->group = bla_dst->group;
1061 	}
1062 
1063 	batadv_orig_node_put(orig_node);
1064 
1065 	return 2;
1066 }
1067 
1068 /**
1069  * batadv_bla_process_claim() - Check if this is a claim frame, and process it
1070  * @bat_priv: the bat priv with all the soft interface information
1071  * @primary_if: the primary hard interface of this batman soft interface
1072  * @skb: the frame to be checked
1073  *
1074  * Return: true if it was a claim frame, otherwise return false to
1075  * tell the callee that it can use the frame on its own.
1076  */
1077 static bool batadv_bla_process_claim(struct batadv_priv *bat_priv,
1078 				     struct batadv_hard_iface *primary_if,
1079 				     struct sk_buff *skb)
1080 {
1081 	struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
1082 	u8 *hw_src, *hw_dst;
1083 	struct vlan_hdr *vhdr, vhdr_buf;
1084 	struct ethhdr *ethhdr;
1085 	struct arphdr *arphdr;
1086 	unsigned short vid;
1087 	int vlan_depth = 0;
1088 	__be16 proto;
1089 	int headlen;
1090 	int ret;
1091 
1092 	vid = batadv_get_vid(skb, 0);
1093 	ethhdr = eth_hdr(skb);
1094 
1095 	proto = ethhdr->h_proto;
1096 	headlen = ETH_HLEN;
1097 	if (vid & BATADV_VLAN_HAS_TAG) {
1098 		/* Traverse the VLAN/Ethertypes.
1099 		 *
1100 		 * At this point it is known that the first protocol is a VLAN
1101 		 * header, so start checking at the encapsulated protocol.
1102 		 *
1103 		 * The depth of the VLAN headers is recorded to drop BLA claim
1104 		 * frames encapsulated into multiple VLAN headers (QinQ).
1105 		 */
1106 		do {
1107 			vhdr = skb_header_pointer(skb, headlen, VLAN_HLEN,
1108 						  &vhdr_buf);
1109 			if (!vhdr)
1110 				return false;
1111 
1112 			proto = vhdr->h_vlan_encapsulated_proto;
1113 			headlen += VLAN_HLEN;
1114 			vlan_depth++;
1115 		} while (proto == htons(ETH_P_8021Q));
1116 	}
1117 
1118 	if (proto != htons(ETH_P_ARP))
1119 		return false; /* not a claim frame */
1120 
1121 	/* this must be a ARP frame. check if it is a claim. */
1122 
1123 	if (unlikely(!pskb_may_pull(skb, headlen + arp_hdr_len(skb->dev))))
1124 		return false;
1125 
1126 	/* pskb_may_pull() may have modified the pointers, get ethhdr again */
1127 	ethhdr = eth_hdr(skb);
1128 	arphdr = (struct arphdr *)((u8 *)ethhdr + headlen);
1129 
1130 	/* Check whether the ARP frame carries a valid
1131 	 * IP information
1132 	 */
1133 	if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
1134 		return false;
1135 	if (arphdr->ar_pro != htons(ETH_P_IP))
1136 		return false;
1137 	if (arphdr->ar_hln != ETH_ALEN)
1138 		return false;
1139 	if (arphdr->ar_pln != 4)
1140 		return false;
1141 
1142 	hw_src = (u8 *)arphdr + sizeof(struct arphdr);
1143 	hw_dst = hw_src + ETH_ALEN + 4;
1144 	bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
1145 	bla_dst_own = &bat_priv->bla.claim_dest;
1146 
1147 	/* check if it is a claim frame in general */
1148 	if (memcmp(bla_dst->magic, bla_dst_own->magic,
1149 		   sizeof(bla_dst->magic)) != 0)
1150 		return false;
1151 
1152 	/* check if there is a claim frame encapsulated deeper in (QinQ) and
1153 	 * drop that, as this is not supported by BLA but should also not be
1154 	 * sent via the mesh.
1155 	 */
1156 	if (vlan_depth > 1)
1157 		return true;
1158 
1159 	/* Let the loopdetect frames on the mesh in any case. */
1160 	if (bla_dst->type == BATADV_CLAIM_TYPE_LOOPDETECT)
1161 		return false;
1162 
1163 	/* check if it is a claim frame. */
1164 	ret = batadv_check_claim_group(bat_priv, primary_if, hw_src, hw_dst,
1165 				       ethhdr);
1166 	if (ret == 1)
1167 		batadv_dbg(BATADV_DBG_BLA, bat_priv,
1168 			   "%s(): received a claim frame from another group. From: %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
1169 			   __func__, ethhdr->h_source, batadv_print_vid(vid),
1170 			   hw_src, hw_dst);
1171 
1172 	if (ret < 2)
1173 		return !!ret;
1174 
1175 	/* become a backbone gw ourselves on this vlan if not happened yet */
1176 	batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1177 
1178 	/* check for the different types of claim frames ... */
1179 	switch (bla_dst->type) {
1180 	case BATADV_CLAIM_TYPE_CLAIM:
1181 		if (batadv_handle_claim(bat_priv, primary_if, hw_src,
1182 					ethhdr->h_source, vid))
1183 			return true;
1184 		break;
1185 	case BATADV_CLAIM_TYPE_UNCLAIM:
1186 		if (batadv_handle_unclaim(bat_priv, primary_if,
1187 					  ethhdr->h_source, hw_src, vid))
1188 			return true;
1189 		break;
1190 
1191 	case BATADV_CLAIM_TYPE_ANNOUNCE:
1192 		if (batadv_handle_announce(bat_priv, hw_src, ethhdr->h_source,
1193 					   vid))
1194 			return true;
1195 		break;
1196 	case BATADV_CLAIM_TYPE_REQUEST:
1197 		if (batadv_handle_request(bat_priv, primary_if, hw_src, ethhdr,
1198 					  vid))
1199 			return true;
1200 		break;
1201 	}
1202 
1203 	batadv_dbg(BATADV_DBG_BLA, bat_priv,
1204 		   "%s(): ERROR - this looks like a claim frame, but is useless. eth src %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
1205 		   __func__, ethhdr->h_source, batadv_print_vid(vid), hw_src,
1206 		   hw_dst);
1207 	return true;
1208 }
1209 
1210 /**
1211  * batadv_bla_purge_backbone_gw() - Remove backbone gateways after a timeout or
1212  *  immediately
1213  * @bat_priv: the bat priv with all the soft interface information
1214  * @now: whether the whole hash shall be wiped now
1215  *
1216  * Check when we last heard from other nodes, and remove them in case of
1217  * a time out, or clean all backbone gws if now is set.
1218  */
1219 static void batadv_bla_purge_backbone_gw(struct batadv_priv *bat_priv, int now)
1220 {
1221 	struct batadv_bla_backbone_gw *backbone_gw;
1222 	struct hlist_node *node_tmp;
1223 	struct hlist_head *head;
1224 	struct batadv_hashtable *hash;
1225 	spinlock_t *list_lock;	/* protects write access to the hash lists */
1226 	int i;
1227 
1228 	hash = bat_priv->bla.backbone_hash;
1229 	if (!hash)
1230 		return;
1231 
1232 	for (i = 0; i < hash->size; i++) {
1233 		head = &hash->table[i];
1234 		list_lock = &hash->list_locks[i];
1235 
1236 		spin_lock_bh(list_lock);
1237 		hlist_for_each_entry_safe(backbone_gw, node_tmp,
1238 					  head, hash_entry) {
1239 			if (now)
1240 				goto purge_now;
1241 			if (!batadv_has_timed_out(backbone_gw->lasttime,
1242 						  BATADV_BLA_BACKBONE_TIMEOUT))
1243 				continue;
1244 
1245 			batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
1246 				   "%s(): backbone gw %pM timed out\n",
1247 				   __func__, backbone_gw->orig);
1248 
1249 purge_now:
1250 			/* don't wait for the pending request anymore */
1251 			if (atomic_read(&backbone_gw->request_sent))
1252 				atomic_dec(&bat_priv->bla.num_requests);
1253 
1254 			batadv_bla_del_backbone_claims(backbone_gw);
1255 
1256 			hlist_del_rcu(&backbone_gw->hash_entry);
1257 			batadv_backbone_gw_put(backbone_gw);
1258 		}
1259 		spin_unlock_bh(list_lock);
1260 	}
1261 }
1262 
1263 /**
1264  * batadv_bla_purge_claims() - Remove claims after a timeout or immediately
1265  * @bat_priv: the bat priv with all the soft interface information
1266  * @primary_if: the selected primary interface, may be NULL if now is set
1267  * @now: whether the whole hash shall be wiped now
1268  *
1269  * Check when we heard last time from our own claims, and remove them in case of
1270  * a time out, or clean all claims if now is set
1271  */
1272 static void batadv_bla_purge_claims(struct batadv_priv *bat_priv,
1273 				    struct batadv_hard_iface *primary_if,
1274 				    int now)
1275 {
1276 	struct batadv_bla_backbone_gw *backbone_gw;
1277 	struct batadv_bla_claim *claim;
1278 	struct hlist_head *head;
1279 	struct batadv_hashtable *hash;
1280 	int i;
1281 
1282 	hash = bat_priv->bla.claim_hash;
1283 	if (!hash)
1284 		return;
1285 
1286 	for (i = 0; i < hash->size; i++) {
1287 		head = &hash->table[i];
1288 
1289 		rcu_read_lock();
1290 		hlist_for_each_entry_rcu(claim, head, hash_entry) {
1291 			backbone_gw = batadv_bla_claim_get_backbone_gw(claim);
1292 			if (now)
1293 				goto purge_now;
1294 
1295 			if (!batadv_compare_eth(backbone_gw->orig,
1296 						primary_if->net_dev->dev_addr))
1297 				goto skip;
1298 
1299 			if (!batadv_has_timed_out(claim->lasttime,
1300 						  BATADV_BLA_CLAIM_TIMEOUT))
1301 				goto skip;
1302 
1303 			batadv_dbg(BATADV_DBG_BLA, bat_priv,
1304 				   "%s(): timed out.\n", __func__);
1305 
1306 purge_now:
1307 			batadv_dbg(BATADV_DBG_BLA, bat_priv,
1308 				   "%s(): %pM, vid %d\n", __func__,
1309 				   claim->addr, claim->vid);
1310 
1311 			batadv_handle_unclaim(bat_priv, primary_if,
1312 					      backbone_gw->orig,
1313 					      claim->addr, claim->vid);
1314 skip:
1315 			batadv_backbone_gw_put(backbone_gw);
1316 		}
1317 		rcu_read_unlock();
1318 	}
1319 }
1320 
1321 /**
1322  * batadv_bla_update_orig_address() - Update the backbone gateways when the own
1323  *  originator address changes
1324  * @bat_priv: the bat priv with all the soft interface information
1325  * @primary_if: the new selected primary_if
1326  * @oldif: the old primary interface, may be NULL
1327  */
1328 void batadv_bla_update_orig_address(struct batadv_priv *bat_priv,
1329 				    struct batadv_hard_iface *primary_if,
1330 				    struct batadv_hard_iface *oldif)
1331 {
1332 	struct batadv_bla_backbone_gw *backbone_gw;
1333 	struct hlist_head *head;
1334 	struct batadv_hashtable *hash;
1335 	__be16 group;
1336 	int i;
1337 
1338 	/* reset bridge loop avoidance group id */
1339 	group = htons(crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN));
1340 	bat_priv->bla.claim_dest.group = group;
1341 
1342 	/* purge everything when bridge loop avoidance is turned off */
1343 	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1344 		oldif = NULL;
1345 
1346 	if (!oldif) {
1347 		batadv_bla_purge_claims(bat_priv, NULL, 1);
1348 		batadv_bla_purge_backbone_gw(bat_priv, 1);
1349 		return;
1350 	}
1351 
1352 	hash = bat_priv->bla.backbone_hash;
1353 	if (!hash)
1354 		return;
1355 
1356 	for (i = 0; i < hash->size; i++) {
1357 		head = &hash->table[i];
1358 
1359 		rcu_read_lock();
1360 		hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1361 			/* own orig still holds the old value. */
1362 			if (!batadv_compare_eth(backbone_gw->orig,
1363 						oldif->net_dev->dev_addr))
1364 				continue;
1365 
1366 			ether_addr_copy(backbone_gw->orig,
1367 					primary_if->net_dev->dev_addr);
1368 			/* send an announce frame so others will ask for our
1369 			 * claims and update their tables.
1370 			 */
1371 			batadv_bla_send_announce(bat_priv, backbone_gw);
1372 		}
1373 		rcu_read_unlock();
1374 	}
1375 }
1376 
1377 /**
1378  * batadv_bla_send_loopdetect() - send a loopdetect frame
1379  * @bat_priv: the bat priv with all the soft interface information
1380  * @backbone_gw: the backbone gateway for which a loop should be detected
1381  *
1382  * To detect loops that the bridge loop avoidance can't handle, send a loop
1383  * detection packet on the backbone. Unlike other BLA frames, this frame will
1384  * be allowed on the mesh by other nodes. If it is received on the mesh, this
1385  * indicates that there is a loop.
1386  */
1387 static void
1388 batadv_bla_send_loopdetect(struct batadv_priv *bat_priv,
1389 			   struct batadv_bla_backbone_gw *backbone_gw)
1390 {
1391 	batadv_dbg(BATADV_DBG_BLA, bat_priv, "Send loopdetect frame for vid %d\n",
1392 		   backbone_gw->vid);
1393 	batadv_bla_send_claim(bat_priv, bat_priv->bla.loopdetect_addr,
1394 			      backbone_gw->vid, BATADV_CLAIM_TYPE_LOOPDETECT);
1395 }
1396 
1397 /**
1398  * batadv_bla_status_update() - purge bla interfaces if necessary
1399  * @net_dev: the soft interface net device
1400  */
1401 void batadv_bla_status_update(struct net_device *net_dev)
1402 {
1403 	struct batadv_priv *bat_priv = netdev_priv(net_dev);
1404 	struct batadv_hard_iface *primary_if;
1405 
1406 	primary_if = batadv_primary_if_get_selected(bat_priv);
1407 	if (!primary_if)
1408 		return;
1409 
1410 	/* this function already purges everything when bla is disabled,
1411 	 * so just call that one.
1412 	 */
1413 	batadv_bla_update_orig_address(bat_priv, primary_if, primary_if);
1414 	batadv_hardif_put(primary_if);
1415 }
1416 
1417 /**
1418  * batadv_bla_periodic_work() - performs periodic bla work
1419  * @work: kernel work struct
1420  *
1421  * periodic work to do:
1422  *  * purge structures when they are too old
1423  *  * send announcements
1424  */
1425 static void batadv_bla_periodic_work(struct work_struct *work)
1426 {
1427 	struct delayed_work *delayed_work;
1428 	struct batadv_priv *bat_priv;
1429 	struct batadv_priv_bla *priv_bla;
1430 	struct hlist_head *head;
1431 	struct batadv_bla_backbone_gw *backbone_gw;
1432 	struct batadv_hashtable *hash;
1433 	struct batadv_hard_iface *primary_if;
1434 	bool send_loopdetect = false;
1435 	int i;
1436 
1437 	delayed_work = to_delayed_work(work);
1438 	priv_bla = container_of(delayed_work, struct batadv_priv_bla, work);
1439 	bat_priv = container_of(priv_bla, struct batadv_priv, bla);
1440 	primary_if = batadv_primary_if_get_selected(bat_priv);
1441 	if (!primary_if)
1442 		goto out;
1443 
1444 	batadv_bla_purge_claims(bat_priv, primary_if, 0);
1445 	batadv_bla_purge_backbone_gw(bat_priv, 0);
1446 
1447 	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1448 		goto out;
1449 
1450 	if (atomic_dec_and_test(&bat_priv->bla.loopdetect_next)) {
1451 		/* set a new random mac address for the next bridge loop
1452 		 * detection frames. Set the locally administered bit to avoid
1453 		 * collisions with users mac addresses.
1454 		 */
1455 		eth_random_addr(bat_priv->bla.loopdetect_addr);
1456 		bat_priv->bla.loopdetect_addr[0] = 0xba;
1457 		bat_priv->bla.loopdetect_addr[1] = 0xbe;
1458 		bat_priv->bla.loopdetect_lasttime = jiffies;
1459 		atomic_set(&bat_priv->bla.loopdetect_next,
1460 			   BATADV_BLA_LOOPDETECT_PERIODS);
1461 
1462 		/* mark for sending loop detect on all VLANs */
1463 		send_loopdetect = true;
1464 	}
1465 
1466 	hash = bat_priv->bla.backbone_hash;
1467 	if (!hash)
1468 		goto out;
1469 
1470 	for (i = 0; i < hash->size; i++) {
1471 		head = &hash->table[i];
1472 
1473 		rcu_read_lock();
1474 		hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1475 			if (!batadv_compare_eth(backbone_gw->orig,
1476 						primary_if->net_dev->dev_addr))
1477 				continue;
1478 
1479 			backbone_gw->lasttime = jiffies;
1480 
1481 			batadv_bla_send_announce(bat_priv, backbone_gw);
1482 			if (send_loopdetect)
1483 				batadv_bla_send_loopdetect(bat_priv,
1484 							   backbone_gw);
1485 
1486 			/* request_sent is only set after creation to avoid
1487 			 * problems when we are not yet known as backbone gw
1488 			 * in the backbone.
1489 			 *
1490 			 * We can reset this now after we waited some periods
1491 			 * to give bridge forward delays and bla group forming
1492 			 * some grace time.
1493 			 */
1494 
1495 			if (atomic_read(&backbone_gw->request_sent) == 0)
1496 				continue;
1497 
1498 			if (!atomic_dec_and_test(&backbone_gw->wait_periods))
1499 				continue;
1500 
1501 			atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
1502 			atomic_set(&backbone_gw->request_sent, 0);
1503 		}
1504 		rcu_read_unlock();
1505 	}
1506 out:
1507 	batadv_hardif_put(primary_if);
1508 
1509 	queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
1510 			   msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
1511 }
1512 
1513 /* The hash for claim and backbone hash receive the same key because they
1514  * are getting initialized by hash_new with the same key. Reinitializing
1515  * them with to different keys to allow nested locking without generating
1516  * lockdep warnings
1517  */
1518 static struct lock_class_key batadv_claim_hash_lock_class_key;
1519 static struct lock_class_key batadv_backbone_hash_lock_class_key;
1520 
1521 /**
1522  * batadv_bla_init() - initialize all bla structures
1523  * @bat_priv: the bat priv with all the soft interface information
1524  *
1525  * Return: 0 on success, < 0 on error.
1526  */
1527 int batadv_bla_init(struct batadv_priv *bat_priv)
1528 {
1529 	int i;
1530 	u8 claim_dest[ETH_ALEN] = {0xff, 0x43, 0x05, 0x00, 0x00, 0x00};
1531 	struct batadv_hard_iface *primary_if;
1532 	u16 crc;
1533 	unsigned long entrytime;
1534 
1535 	spin_lock_init(&bat_priv->bla.bcast_duplist_lock);
1536 
1537 	batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hash registering\n");
1538 
1539 	/* setting claim destination address */
1540 	memcpy(&bat_priv->bla.claim_dest.magic, claim_dest, 3);
1541 	bat_priv->bla.claim_dest.type = 0;
1542 	primary_if = batadv_primary_if_get_selected(bat_priv);
1543 	if (primary_if) {
1544 		crc = crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN);
1545 		bat_priv->bla.claim_dest.group = htons(crc);
1546 		batadv_hardif_put(primary_if);
1547 	} else {
1548 		bat_priv->bla.claim_dest.group = 0; /* will be set later */
1549 	}
1550 
1551 	/* initialize the duplicate list */
1552 	entrytime = jiffies - msecs_to_jiffies(BATADV_DUPLIST_TIMEOUT);
1553 	for (i = 0; i < BATADV_DUPLIST_SIZE; i++)
1554 		bat_priv->bla.bcast_duplist[i].entrytime = entrytime;
1555 	bat_priv->bla.bcast_duplist_curr = 0;
1556 
1557 	atomic_set(&bat_priv->bla.loopdetect_next,
1558 		   BATADV_BLA_LOOPDETECT_PERIODS);
1559 
1560 	if (bat_priv->bla.claim_hash)
1561 		return 0;
1562 
1563 	bat_priv->bla.claim_hash = batadv_hash_new(128);
1564 	if (!bat_priv->bla.claim_hash)
1565 		return -ENOMEM;
1566 
1567 	bat_priv->bla.backbone_hash = batadv_hash_new(32);
1568 	if (!bat_priv->bla.backbone_hash) {
1569 		batadv_hash_destroy(bat_priv->bla.claim_hash);
1570 		return -ENOMEM;
1571 	}
1572 
1573 	batadv_hash_set_lock_class(bat_priv->bla.claim_hash,
1574 				   &batadv_claim_hash_lock_class_key);
1575 	batadv_hash_set_lock_class(bat_priv->bla.backbone_hash,
1576 				   &batadv_backbone_hash_lock_class_key);
1577 
1578 	batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hashes initialized\n");
1579 
1580 	INIT_DELAYED_WORK(&bat_priv->bla.work, batadv_bla_periodic_work);
1581 
1582 	queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
1583 			   msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
1584 	return 0;
1585 }
1586 
1587 /**
1588  * batadv_bla_check_duplist() - Check if a frame is in the broadcast dup.
1589  * @bat_priv: the bat priv with all the soft interface information
1590  * @skb: contains the multicast packet to be checked
1591  * @payload_ptr: pointer to position inside the head buffer of the skb
1592  *  marking the start of the data to be CRC'ed
1593  * @orig: originator mac address, NULL if unknown
1594  *
1595  * Check if it is on our broadcast list. Another gateway might have sent the
1596  * same packet because it is connected to the same backbone, so we have to
1597  * remove this duplicate.
1598  *
1599  * This is performed by checking the CRC, which will tell us
1600  * with a good chance that it is the same packet. If it is furthermore
1601  * sent by another host, drop it. We allow equal packets from
1602  * the same host however as this might be intended.
1603  *
1604  * Return: true if a packet is in the duplicate list, false otherwise.
1605  */
1606 static bool batadv_bla_check_duplist(struct batadv_priv *bat_priv,
1607 				     struct sk_buff *skb, u8 *payload_ptr,
1608 				     const u8 *orig)
1609 {
1610 	struct batadv_bcast_duplist_entry *entry;
1611 	bool ret = false;
1612 	int i, curr;
1613 	__be32 crc;
1614 
1615 	/* calculate the crc ... */
1616 	crc = batadv_skb_crc32(skb, payload_ptr);
1617 
1618 	spin_lock_bh(&bat_priv->bla.bcast_duplist_lock);
1619 
1620 	for (i = 0; i < BATADV_DUPLIST_SIZE; i++) {
1621 		curr = (bat_priv->bla.bcast_duplist_curr + i);
1622 		curr %= BATADV_DUPLIST_SIZE;
1623 		entry = &bat_priv->bla.bcast_duplist[curr];
1624 
1625 		/* we can stop searching if the entry is too old ;
1626 		 * later entries will be even older
1627 		 */
1628 		if (batadv_has_timed_out(entry->entrytime,
1629 					 BATADV_DUPLIST_TIMEOUT))
1630 			break;
1631 
1632 		if (entry->crc != crc)
1633 			continue;
1634 
1635 		/* are the originators both known and not anonymous? */
1636 		if (orig && !is_zero_ether_addr(orig) &&
1637 		    !is_zero_ether_addr(entry->orig)) {
1638 			/* If known, check if the new frame came from
1639 			 * the same originator:
1640 			 * We are safe to take identical frames from the
1641 			 * same orig, if known, as multiplications in
1642 			 * the mesh are detected via the (orig, seqno) pair.
1643 			 * So we can be a bit more liberal here and allow
1644 			 * identical frames from the same orig which the source
1645 			 * host might have sent multiple times on purpose.
1646 			 */
1647 			if (batadv_compare_eth(entry->orig, orig))
1648 				continue;
1649 		}
1650 
1651 		/* this entry seems to match: same crc, not too old,
1652 		 * and from another gw. therefore return true to forbid it.
1653 		 */
1654 		ret = true;
1655 		goto out;
1656 	}
1657 	/* not found, add a new entry (overwrite the oldest entry)
1658 	 * and allow it, its the first occurrence.
1659 	 */
1660 	curr = (bat_priv->bla.bcast_duplist_curr + BATADV_DUPLIST_SIZE - 1);
1661 	curr %= BATADV_DUPLIST_SIZE;
1662 	entry = &bat_priv->bla.bcast_duplist[curr];
1663 	entry->crc = crc;
1664 	entry->entrytime = jiffies;
1665 
1666 	/* known originator */
1667 	if (orig)
1668 		ether_addr_copy(entry->orig, orig);
1669 	/* anonymous originator */
1670 	else
1671 		eth_zero_addr(entry->orig);
1672 
1673 	bat_priv->bla.bcast_duplist_curr = curr;
1674 
1675 out:
1676 	spin_unlock_bh(&bat_priv->bla.bcast_duplist_lock);
1677 
1678 	return ret;
1679 }
1680 
1681 /**
1682  * batadv_bla_check_ucast_duplist() - Check if a frame is in the broadcast dup.
1683  * @bat_priv: the bat priv with all the soft interface information
1684  * @skb: contains the multicast packet to be checked, decapsulated from a
1685  *  unicast_packet
1686  *
1687  * Check if it is on our broadcast list. Another gateway might have sent the
1688  * same packet because it is connected to the same backbone, so we have to
1689  * remove this duplicate.
1690  *
1691  * Return: true if a packet is in the duplicate list, false otherwise.
1692  */
1693 static bool batadv_bla_check_ucast_duplist(struct batadv_priv *bat_priv,
1694 					   struct sk_buff *skb)
1695 {
1696 	return batadv_bla_check_duplist(bat_priv, skb, (u8 *)skb->data, NULL);
1697 }
1698 
1699 /**
1700  * batadv_bla_check_bcast_duplist() - Check if a frame is in the broadcast dup.
1701  * @bat_priv: the bat priv with all the soft interface information
1702  * @skb: contains the bcast_packet to be checked
1703  *
1704  * Check if it is on our broadcast list. Another gateway might have sent the
1705  * same packet because it is connected to the same backbone, so we have to
1706  * remove this duplicate.
1707  *
1708  * Return: true if a packet is in the duplicate list, false otherwise.
1709  */
1710 bool batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
1711 				    struct sk_buff *skb)
1712 {
1713 	struct batadv_bcast_packet *bcast_packet;
1714 	u8 *payload_ptr;
1715 
1716 	bcast_packet = (struct batadv_bcast_packet *)skb->data;
1717 	payload_ptr = (u8 *)(bcast_packet + 1);
1718 
1719 	return batadv_bla_check_duplist(bat_priv, skb, payload_ptr,
1720 					bcast_packet->orig);
1721 }
1722 
1723 /**
1724  * batadv_bla_is_backbone_gw_orig() - Check if the originator is a gateway for
1725  *  the VLAN identified by vid.
1726  * @bat_priv: the bat priv with all the soft interface information
1727  * @orig: originator mac address
1728  * @vid: VLAN identifier
1729  *
1730  * Return: true if orig is a backbone for this vid, false otherwise.
1731  */
1732 bool batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, u8 *orig,
1733 				    unsigned short vid)
1734 {
1735 	struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
1736 	struct hlist_head *head;
1737 	struct batadv_bla_backbone_gw *backbone_gw;
1738 	int i;
1739 
1740 	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1741 		return false;
1742 
1743 	if (!hash)
1744 		return false;
1745 
1746 	for (i = 0; i < hash->size; i++) {
1747 		head = &hash->table[i];
1748 
1749 		rcu_read_lock();
1750 		hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
1751 			if (batadv_compare_eth(backbone_gw->orig, orig) &&
1752 			    backbone_gw->vid == vid) {
1753 				rcu_read_unlock();
1754 				return true;
1755 			}
1756 		}
1757 		rcu_read_unlock();
1758 	}
1759 
1760 	return false;
1761 }
1762 
1763 /**
1764  * batadv_bla_is_backbone_gw() - check if originator is a backbone gw for a VLAN
1765  * @skb: the frame to be checked
1766  * @orig_node: the orig_node of the frame
1767  * @hdr_size: maximum length of the frame
1768  *
1769  * Return: true if the orig_node is also a gateway on the soft interface,
1770  * otherwise it returns false.
1771  */
1772 bool batadv_bla_is_backbone_gw(struct sk_buff *skb,
1773 			       struct batadv_orig_node *orig_node, int hdr_size)
1774 {
1775 	struct batadv_bla_backbone_gw *backbone_gw;
1776 	unsigned short vid;
1777 
1778 	if (!atomic_read(&orig_node->bat_priv->bridge_loop_avoidance))
1779 		return false;
1780 
1781 	/* first, find out the vid. */
1782 	if (!pskb_may_pull(skb, hdr_size + ETH_HLEN))
1783 		return false;
1784 
1785 	vid = batadv_get_vid(skb, hdr_size);
1786 
1787 	/* see if this originator is a backbone gw for this VLAN */
1788 	backbone_gw = batadv_backbone_hash_find(orig_node->bat_priv,
1789 						orig_node->orig, vid);
1790 	if (!backbone_gw)
1791 		return false;
1792 
1793 	batadv_backbone_gw_put(backbone_gw);
1794 	return true;
1795 }
1796 
1797 /**
1798  * batadv_bla_free() - free all bla structures
1799  * @bat_priv: the bat priv with all the soft interface information
1800  *
1801  * for softinterface free or module unload
1802  */
1803 void batadv_bla_free(struct batadv_priv *bat_priv)
1804 {
1805 	struct batadv_hard_iface *primary_if;
1806 
1807 	cancel_delayed_work_sync(&bat_priv->bla.work);
1808 	primary_if = batadv_primary_if_get_selected(bat_priv);
1809 
1810 	if (bat_priv->bla.claim_hash) {
1811 		batadv_bla_purge_claims(bat_priv, primary_if, 1);
1812 		batadv_hash_destroy(bat_priv->bla.claim_hash);
1813 		bat_priv->bla.claim_hash = NULL;
1814 	}
1815 	if (bat_priv->bla.backbone_hash) {
1816 		batadv_bla_purge_backbone_gw(bat_priv, 1);
1817 		batadv_hash_destroy(bat_priv->bla.backbone_hash);
1818 		bat_priv->bla.backbone_hash = NULL;
1819 	}
1820 	batadv_hardif_put(primary_if);
1821 }
1822 
1823 /**
1824  * batadv_bla_loopdetect_check() - check and handle a detected loop
1825  * @bat_priv: the bat priv with all the soft interface information
1826  * @skb: the packet to check
1827  * @primary_if: interface where the request came on
1828  * @vid: the VLAN ID of the frame
1829  *
1830  * Checks if this packet is a loop detect frame which has been sent by us,
1831  * throws an uevent and logs the event if that is the case.
1832  *
1833  * Return: true if it is a loop detect frame which is to be dropped, false
1834  * otherwise.
1835  */
1836 static bool
1837 batadv_bla_loopdetect_check(struct batadv_priv *bat_priv, struct sk_buff *skb,
1838 			    struct batadv_hard_iface *primary_if,
1839 			    unsigned short vid)
1840 {
1841 	struct batadv_bla_backbone_gw *backbone_gw;
1842 	struct ethhdr *ethhdr;
1843 	bool ret;
1844 
1845 	ethhdr = eth_hdr(skb);
1846 
1847 	/* Only check for the MAC address and skip more checks here for
1848 	 * performance reasons - this function is on the hotpath, after all.
1849 	 */
1850 	if (!batadv_compare_eth(ethhdr->h_source,
1851 				bat_priv->bla.loopdetect_addr))
1852 		return false;
1853 
1854 	/* If the packet came too late, don't forward it on the mesh
1855 	 * but don't consider that as loop. It might be a coincidence.
1856 	 */
1857 	if (batadv_has_timed_out(bat_priv->bla.loopdetect_lasttime,
1858 				 BATADV_BLA_LOOPDETECT_TIMEOUT))
1859 		return true;
1860 
1861 	backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
1862 						 primary_if->net_dev->dev_addr,
1863 						 vid, true);
1864 	if (unlikely(!backbone_gw))
1865 		return true;
1866 
1867 	ret = queue_work(batadv_event_workqueue, &backbone_gw->report_work);
1868 
1869 	/* backbone_gw is unreferenced in the report work function
1870 	 * if queue_work() call was successful
1871 	 */
1872 	if (!ret)
1873 		batadv_backbone_gw_put(backbone_gw);
1874 
1875 	return true;
1876 }
1877 
1878 /**
1879  * batadv_bla_rx() - check packets coming from the mesh.
1880  * @bat_priv: the bat priv with all the soft interface information
1881  * @skb: the frame to be checked
1882  * @vid: the VLAN ID of the frame
1883  * @packet_type: the batman packet type this frame came in
1884  *
1885  * batadv_bla_rx avoidance checks if:
1886  *  * we have to race for a claim
1887  *  * if the frame is allowed on the LAN
1888  *
1889  * In these cases, the skb is further handled by this function
1890  *
1891  * Return: true if handled, otherwise it returns false and the caller shall
1892  * further process the skb.
1893  */
1894 bool batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb,
1895 		   unsigned short vid, int packet_type)
1896 {
1897 	struct batadv_bla_backbone_gw *backbone_gw;
1898 	struct ethhdr *ethhdr;
1899 	struct batadv_bla_claim search_claim, *claim = NULL;
1900 	struct batadv_hard_iface *primary_if;
1901 	bool own_claim;
1902 	bool ret;
1903 
1904 	ethhdr = eth_hdr(skb);
1905 
1906 	primary_if = batadv_primary_if_get_selected(bat_priv);
1907 	if (!primary_if)
1908 		goto handled;
1909 
1910 	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
1911 		goto allow;
1912 
1913 	if (batadv_bla_loopdetect_check(bat_priv, skb, primary_if, vid))
1914 		goto handled;
1915 
1916 	if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
1917 		/* don't allow multicast packets while requests are in flight */
1918 		if (is_multicast_ether_addr(ethhdr->h_dest))
1919 			/* Both broadcast flooding or multicast-via-unicasts
1920 			 * delivery might send to multiple backbone gateways
1921 			 * sharing the same LAN and therefore need to coordinate
1922 			 * which backbone gateway forwards into the LAN,
1923 			 * by claiming the payload source address.
1924 			 *
1925 			 * Broadcast flooding and multicast-via-unicasts
1926 			 * delivery use the following two batman packet types.
1927 			 * Note: explicitly exclude BATADV_UNICAST_4ADDR,
1928 			 * as the DHCP gateway feature will send explicitly
1929 			 * to only one BLA gateway, so the claiming process
1930 			 * should be avoided there.
1931 			 */
1932 			if (packet_type == BATADV_BCAST ||
1933 			    packet_type == BATADV_UNICAST)
1934 				goto handled;
1935 
1936 	/* potential duplicates from foreign BLA backbone gateways via
1937 	 * multicast-in-unicast packets
1938 	 */
1939 	if (is_multicast_ether_addr(ethhdr->h_dest) &&
1940 	    packet_type == BATADV_UNICAST &&
1941 	    batadv_bla_check_ucast_duplist(bat_priv, skb))
1942 		goto handled;
1943 
1944 	ether_addr_copy(search_claim.addr, ethhdr->h_source);
1945 	search_claim.vid = vid;
1946 	claim = batadv_claim_hash_find(bat_priv, &search_claim);
1947 
1948 	if (!claim) {
1949 		/* possible optimization: race for a claim */
1950 		/* No claim exists yet, claim it for us!
1951 		 */
1952 
1953 		batadv_dbg(BATADV_DBG_BLA, bat_priv,
1954 			   "%s(): Unclaimed MAC %pM found. Claim it. Local: %s\n",
1955 			   __func__, ethhdr->h_source,
1956 			   batadv_is_my_client(bat_priv,
1957 					       ethhdr->h_source, vid) ?
1958 			   "yes" : "no");
1959 		batadv_handle_claim(bat_priv, primary_if,
1960 				    primary_if->net_dev->dev_addr,
1961 				    ethhdr->h_source, vid);
1962 		goto allow;
1963 	}
1964 
1965 	/* if it is our own claim ... */
1966 	backbone_gw = batadv_bla_claim_get_backbone_gw(claim);
1967 	own_claim = batadv_compare_eth(backbone_gw->orig,
1968 				       primary_if->net_dev->dev_addr);
1969 	batadv_backbone_gw_put(backbone_gw);
1970 
1971 	if (own_claim) {
1972 		/* ... allow it in any case */
1973 		claim->lasttime = jiffies;
1974 		goto allow;
1975 	}
1976 
1977 	/* if it is a multicast ... */
1978 	if (is_multicast_ether_addr(ethhdr->h_dest) &&
1979 	    (packet_type == BATADV_BCAST || packet_type == BATADV_UNICAST)) {
1980 		/* ... drop it. the responsible gateway is in charge.
1981 		 *
1982 		 * We need to check packet type because with the gateway
1983 		 * feature, broadcasts (like DHCP requests) may be sent
1984 		 * using a unicast 4 address packet type. See comment above.
1985 		 */
1986 		goto handled;
1987 	} else {
1988 		/* seems the client considers us as its best gateway.
1989 		 * send a claim and update the claim table
1990 		 * immediately.
1991 		 */
1992 		batadv_handle_claim(bat_priv, primary_if,
1993 				    primary_if->net_dev->dev_addr,
1994 				    ethhdr->h_source, vid);
1995 		goto allow;
1996 	}
1997 allow:
1998 	batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
1999 	ret = false;
2000 	goto out;
2001 
2002 handled:
2003 	kfree_skb(skb);
2004 	ret = true;
2005 
2006 out:
2007 	batadv_hardif_put(primary_if);
2008 	batadv_claim_put(claim);
2009 	return ret;
2010 }
2011 
2012 /**
2013  * batadv_bla_tx() - check packets going into the mesh
2014  * @bat_priv: the bat priv with all the soft interface information
2015  * @skb: the frame to be checked
2016  * @vid: the VLAN ID of the frame
2017  *
2018  * batadv_bla_tx checks if:
2019  *  * a claim was received which has to be processed
2020  *  * the frame is allowed on the mesh
2021  *
2022  * in these cases, the skb is further handled by this function.
2023  *
2024  * This call might reallocate skb data.
2025  *
2026  * Return: true if handled, otherwise it returns false and the caller shall
2027  * further process the skb.
2028  */
2029 bool batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb,
2030 		   unsigned short vid)
2031 {
2032 	struct ethhdr *ethhdr;
2033 	struct batadv_bla_claim search_claim, *claim = NULL;
2034 	struct batadv_bla_backbone_gw *backbone_gw;
2035 	struct batadv_hard_iface *primary_if;
2036 	bool client_roamed;
2037 	bool ret = false;
2038 
2039 	primary_if = batadv_primary_if_get_selected(bat_priv);
2040 	if (!primary_if)
2041 		goto out;
2042 
2043 	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
2044 		goto allow;
2045 
2046 	if (batadv_bla_process_claim(bat_priv, primary_if, skb))
2047 		goto handled;
2048 
2049 	ethhdr = eth_hdr(skb);
2050 
2051 	if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
2052 		/* don't allow broadcasts while requests are in flight */
2053 		if (is_multicast_ether_addr(ethhdr->h_dest))
2054 			goto handled;
2055 
2056 	ether_addr_copy(search_claim.addr, ethhdr->h_source);
2057 	search_claim.vid = vid;
2058 
2059 	claim = batadv_claim_hash_find(bat_priv, &search_claim);
2060 
2061 	/* if no claim exists, allow it. */
2062 	if (!claim)
2063 		goto allow;
2064 
2065 	/* check if we are responsible. */
2066 	backbone_gw = batadv_bla_claim_get_backbone_gw(claim);
2067 	client_roamed = batadv_compare_eth(backbone_gw->orig,
2068 					   primary_if->net_dev->dev_addr);
2069 	batadv_backbone_gw_put(backbone_gw);
2070 
2071 	if (client_roamed) {
2072 		/* if yes, the client has roamed and we have
2073 		 * to unclaim it.
2074 		 */
2075 		if (batadv_has_timed_out(claim->lasttime, 100)) {
2076 			/* only unclaim if the last claim entry is
2077 			 * older than 100 ms to make sure we really
2078 			 * have a roaming client here.
2079 			 */
2080 			batadv_dbg(BATADV_DBG_BLA, bat_priv, "%s(): Roaming client %pM detected. Unclaim it.\n",
2081 				   __func__, ethhdr->h_source);
2082 			batadv_handle_unclaim(bat_priv, primary_if,
2083 					      primary_if->net_dev->dev_addr,
2084 					      ethhdr->h_source, vid);
2085 			goto allow;
2086 		} else {
2087 			batadv_dbg(BATADV_DBG_BLA, bat_priv, "%s(): Race for claim %pM detected. Drop packet.\n",
2088 				   __func__, ethhdr->h_source);
2089 			goto handled;
2090 		}
2091 	}
2092 
2093 	/* check if it is a multicast/broadcast frame */
2094 	if (is_multicast_ether_addr(ethhdr->h_dest)) {
2095 		/* drop it. the responsible gateway has forwarded it into
2096 		 * the backbone network.
2097 		 */
2098 		goto handled;
2099 	} else {
2100 		/* we must allow it. at least if we are
2101 		 * responsible for the DESTINATION.
2102 		 */
2103 		goto allow;
2104 	}
2105 allow:
2106 	batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
2107 	ret = false;
2108 	goto out;
2109 handled:
2110 	ret = true;
2111 out:
2112 	batadv_hardif_put(primary_if);
2113 	batadv_claim_put(claim);
2114 	return ret;
2115 }
2116 
2117 /**
2118  * batadv_bla_claim_dump_entry() - dump one entry of the claim table
2119  * to a netlink socket
2120  * @msg: buffer for the message
2121  * @portid: netlink port
2122  * @cb: Control block containing additional options
2123  * @primary_if: primary interface
2124  * @claim: entry to dump
2125  *
2126  * Return: 0 or error code.
2127  */
2128 static int
2129 batadv_bla_claim_dump_entry(struct sk_buff *msg, u32 portid,
2130 			    struct netlink_callback *cb,
2131 			    struct batadv_hard_iface *primary_if,
2132 			    struct batadv_bla_claim *claim)
2133 {
2134 	const u8 *primary_addr = primary_if->net_dev->dev_addr;
2135 	u16 backbone_crc;
2136 	bool is_own;
2137 	void *hdr;
2138 	int ret = -EINVAL;
2139 
2140 	hdr = genlmsg_put(msg, portid, cb->nlh->nlmsg_seq,
2141 			  &batadv_netlink_family, NLM_F_MULTI,
2142 			  BATADV_CMD_GET_BLA_CLAIM);
2143 	if (!hdr) {
2144 		ret = -ENOBUFS;
2145 		goto out;
2146 	}
2147 
2148 	genl_dump_check_consistent(cb, hdr);
2149 
2150 	is_own = batadv_compare_eth(claim->backbone_gw->orig,
2151 				    primary_addr);
2152 
2153 	spin_lock_bh(&claim->backbone_gw->crc_lock);
2154 	backbone_crc = claim->backbone_gw->crc;
2155 	spin_unlock_bh(&claim->backbone_gw->crc_lock);
2156 
2157 	if (is_own)
2158 		if (nla_put_flag(msg, BATADV_ATTR_BLA_OWN)) {
2159 			genlmsg_cancel(msg, hdr);
2160 			goto out;
2161 		}
2162 
2163 	if (nla_put(msg, BATADV_ATTR_BLA_ADDRESS, ETH_ALEN, claim->addr) ||
2164 	    nla_put_u16(msg, BATADV_ATTR_BLA_VID, claim->vid) ||
2165 	    nla_put(msg, BATADV_ATTR_BLA_BACKBONE, ETH_ALEN,
2166 		    claim->backbone_gw->orig) ||
2167 	    nla_put_u16(msg, BATADV_ATTR_BLA_CRC,
2168 			backbone_crc)) {
2169 		genlmsg_cancel(msg, hdr);
2170 		goto out;
2171 	}
2172 
2173 	genlmsg_end(msg, hdr);
2174 	ret = 0;
2175 
2176 out:
2177 	return ret;
2178 }
2179 
2180 /**
2181  * batadv_bla_claim_dump_bucket() - dump one bucket of the claim table
2182  * to a netlink socket
2183  * @msg: buffer for the message
2184  * @portid: netlink port
2185  * @cb: Control block containing additional options
2186  * @primary_if: primary interface
2187  * @hash: hash to dump
2188  * @bucket: bucket index to dump
2189  * @idx_skip: How many entries to skip
2190  *
2191  * Return: always 0.
2192  */
2193 static int
2194 batadv_bla_claim_dump_bucket(struct sk_buff *msg, u32 portid,
2195 			     struct netlink_callback *cb,
2196 			     struct batadv_hard_iface *primary_if,
2197 			     struct batadv_hashtable *hash, unsigned int bucket,
2198 			     int *idx_skip)
2199 {
2200 	struct batadv_bla_claim *claim;
2201 	int idx = 0;
2202 	int ret = 0;
2203 
2204 	spin_lock_bh(&hash->list_locks[bucket]);
2205 	cb->seq = atomic_read(&hash->generation) << 1 | 1;
2206 
2207 	hlist_for_each_entry(claim, &hash->table[bucket], hash_entry) {
2208 		if (idx++ < *idx_skip)
2209 			continue;
2210 
2211 		ret = batadv_bla_claim_dump_entry(msg, portid, cb,
2212 						  primary_if, claim);
2213 		if (ret) {
2214 			*idx_skip = idx - 1;
2215 			goto unlock;
2216 		}
2217 	}
2218 
2219 	*idx_skip = 0;
2220 unlock:
2221 	spin_unlock_bh(&hash->list_locks[bucket]);
2222 	return ret;
2223 }
2224 
2225 /**
2226  * batadv_bla_claim_dump() - dump claim table to a netlink socket
2227  * @msg: buffer for the message
2228  * @cb: callback structure containing arguments
2229  *
2230  * Return: message length.
2231  */
2232 int batadv_bla_claim_dump(struct sk_buff *msg, struct netlink_callback *cb)
2233 {
2234 	struct batadv_hard_iface *primary_if = NULL;
2235 	int portid = NETLINK_CB(cb->skb).portid;
2236 	struct net *net = sock_net(cb->skb->sk);
2237 	struct net_device *soft_iface;
2238 	struct batadv_hashtable *hash;
2239 	struct batadv_priv *bat_priv;
2240 	int bucket = cb->args[0];
2241 	int idx = cb->args[1];
2242 	int ifindex;
2243 	int ret = 0;
2244 
2245 	ifindex = batadv_netlink_get_ifindex(cb->nlh,
2246 					     BATADV_ATTR_MESH_IFINDEX);
2247 	if (!ifindex)
2248 		return -EINVAL;
2249 
2250 	soft_iface = dev_get_by_index(net, ifindex);
2251 	if (!soft_iface || !batadv_softif_is_valid(soft_iface)) {
2252 		ret = -ENODEV;
2253 		goto out;
2254 	}
2255 
2256 	bat_priv = netdev_priv(soft_iface);
2257 	hash = bat_priv->bla.claim_hash;
2258 
2259 	primary_if = batadv_primary_if_get_selected(bat_priv);
2260 	if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) {
2261 		ret = -ENOENT;
2262 		goto out;
2263 	}
2264 
2265 	while (bucket < hash->size) {
2266 		if (batadv_bla_claim_dump_bucket(msg, portid, cb, primary_if,
2267 						 hash, bucket, &idx))
2268 			break;
2269 		bucket++;
2270 	}
2271 
2272 	cb->args[0] = bucket;
2273 	cb->args[1] = idx;
2274 
2275 	ret = msg->len;
2276 
2277 out:
2278 	batadv_hardif_put(primary_if);
2279 
2280 	dev_put(soft_iface);
2281 
2282 	return ret;
2283 }
2284 
2285 /**
2286  * batadv_bla_backbone_dump_entry() - dump one entry of the backbone table to a
2287  *  netlink socket
2288  * @msg: buffer for the message
2289  * @portid: netlink port
2290  * @cb: Control block containing additional options
2291  * @primary_if: primary interface
2292  * @backbone_gw: entry to dump
2293  *
2294  * Return: 0 or error code.
2295  */
2296 static int
2297 batadv_bla_backbone_dump_entry(struct sk_buff *msg, u32 portid,
2298 			       struct netlink_callback *cb,
2299 			       struct batadv_hard_iface *primary_if,
2300 			       struct batadv_bla_backbone_gw *backbone_gw)
2301 {
2302 	const u8 *primary_addr = primary_if->net_dev->dev_addr;
2303 	u16 backbone_crc;
2304 	bool is_own;
2305 	int msecs;
2306 	void *hdr;
2307 	int ret = -EINVAL;
2308 
2309 	hdr = genlmsg_put(msg, portid, cb->nlh->nlmsg_seq,
2310 			  &batadv_netlink_family, NLM_F_MULTI,
2311 			  BATADV_CMD_GET_BLA_BACKBONE);
2312 	if (!hdr) {
2313 		ret = -ENOBUFS;
2314 		goto out;
2315 	}
2316 
2317 	genl_dump_check_consistent(cb, hdr);
2318 
2319 	is_own = batadv_compare_eth(backbone_gw->orig, primary_addr);
2320 
2321 	spin_lock_bh(&backbone_gw->crc_lock);
2322 	backbone_crc = backbone_gw->crc;
2323 	spin_unlock_bh(&backbone_gw->crc_lock);
2324 
2325 	msecs = jiffies_to_msecs(jiffies - backbone_gw->lasttime);
2326 
2327 	if (is_own)
2328 		if (nla_put_flag(msg, BATADV_ATTR_BLA_OWN)) {
2329 			genlmsg_cancel(msg, hdr);
2330 			goto out;
2331 		}
2332 
2333 	if (nla_put(msg, BATADV_ATTR_BLA_BACKBONE, ETH_ALEN,
2334 		    backbone_gw->orig) ||
2335 	    nla_put_u16(msg, BATADV_ATTR_BLA_VID, backbone_gw->vid) ||
2336 	    nla_put_u16(msg, BATADV_ATTR_BLA_CRC,
2337 			backbone_crc) ||
2338 	    nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS, msecs)) {
2339 		genlmsg_cancel(msg, hdr);
2340 		goto out;
2341 	}
2342 
2343 	genlmsg_end(msg, hdr);
2344 	ret = 0;
2345 
2346 out:
2347 	return ret;
2348 }
2349 
2350 /**
2351  * batadv_bla_backbone_dump_bucket() - dump one bucket of the backbone table to
2352  *  a netlink socket
2353  * @msg: buffer for the message
2354  * @portid: netlink port
2355  * @cb: Control block containing additional options
2356  * @primary_if: primary interface
2357  * @hash: hash to dump
2358  * @bucket: bucket index to dump
2359  * @idx_skip: How many entries to skip
2360  *
2361  * Return: always 0.
2362  */
2363 static int
2364 batadv_bla_backbone_dump_bucket(struct sk_buff *msg, u32 portid,
2365 				struct netlink_callback *cb,
2366 				struct batadv_hard_iface *primary_if,
2367 				struct batadv_hashtable *hash,
2368 				unsigned int bucket, int *idx_skip)
2369 {
2370 	struct batadv_bla_backbone_gw *backbone_gw;
2371 	int idx = 0;
2372 	int ret = 0;
2373 
2374 	spin_lock_bh(&hash->list_locks[bucket]);
2375 	cb->seq = atomic_read(&hash->generation) << 1 | 1;
2376 
2377 	hlist_for_each_entry(backbone_gw, &hash->table[bucket], hash_entry) {
2378 		if (idx++ < *idx_skip)
2379 			continue;
2380 
2381 		ret = batadv_bla_backbone_dump_entry(msg, portid, cb,
2382 						     primary_if, backbone_gw);
2383 		if (ret) {
2384 			*idx_skip = idx - 1;
2385 			goto unlock;
2386 		}
2387 	}
2388 
2389 	*idx_skip = 0;
2390 unlock:
2391 	spin_unlock_bh(&hash->list_locks[bucket]);
2392 	return ret;
2393 }
2394 
2395 /**
2396  * batadv_bla_backbone_dump() - dump backbone table to a netlink socket
2397  * @msg: buffer for the message
2398  * @cb: callback structure containing arguments
2399  *
2400  * Return: message length.
2401  */
2402 int batadv_bla_backbone_dump(struct sk_buff *msg, struct netlink_callback *cb)
2403 {
2404 	struct batadv_hard_iface *primary_if = NULL;
2405 	int portid = NETLINK_CB(cb->skb).portid;
2406 	struct net *net = sock_net(cb->skb->sk);
2407 	struct net_device *soft_iface;
2408 	struct batadv_hashtable *hash;
2409 	struct batadv_priv *bat_priv;
2410 	int bucket = cb->args[0];
2411 	int idx = cb->args[1];
2412 	int ifindex;
2413 	int ret = 0;
2414 
2415 	ifindex = batadv_netlink_get_ifindex(cb->nlh,
2416 					     BATADV_ATTR_MESH_IFINDEX);
2417 	if (!ifindex)
2418 		return -EINVAL;
2419 
2420 	soft_iface = dev_get_by_index(net, ifindex);
2421 	if (!soft_iface || !batadv_softif_is_valid(soft_iface)) {
2422 		ret = -ENODEV;
2423 		goto out;
2424 	}
2425 
2426 	bat_priv = netdev_priv(soft_iface);
2427 	hash = bat_priv->bla.backbone_hash;
2428 
2429 	primary_if = batadv_primary_if_get_selected(bat_priv);
2430 	if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) {
2431 		ret = -ENOENT;
2432 		goto out;
2433 	}
2434 
2435 	while (bucket < hash->size) {
2436 		if (batadv_bla_backbone_dump_bucket(msg, portid, cb, primary_if,
2437 						    hash, bucket, &idx))
2438 			break;
2439 		bucket++;
2440 	}
2441 
2442 	cb->args[0] = bucket;
2443 	cb->args[1] = idx;
2444 
2445 	ret = msg->len;
2446 
2447 out:
2448 	batadv_hardif_put(primary_if);
2449 
2450 	dev_put(soft_iface);
2451 
2452 	return ret;
2453 }
2454 
2455 #ifdef CONFIG_BATMAN_ADV_DAT
2456 /**
2457  * batadv_bla_check_claim() - check if address is claimed
2458  *
2459  * @bat_priv: the bat priv with all the soft interface information
2460  * @addr: mac address of which the claim status is checked
2461  * @vid: the VLAN ID
2462  *
2463  * addr is checked if this address is claimed by the local device itself.
2464  *
2465  * Return: true if bla is disabled or the mac is claimed by the device,
2466  * false if the device addr is already claimed by another gateway
2467  */
2468 bool batadv_bla_check_claim(struct batadv_priv *bat_priv,
2469 			    u8 *addr, unsigned short vid)
2470 {
2471 	struct batadv_bla_claim search_claim;
2472 	struct batadv_bla_claim *claim = NULL;
2473 	struct batadv_hard_iface *primary_if = NULL;
2474 	bool ret = true;
2475 
2476 	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
2477 		return ret;
2478 
2479 	primary_if = batadv_primary_if_get_selected(bat_priv);
2480 	if (!primary_if)
2481 		return ret;
2482 
2483 	/* First look if the mac address is claimed */
2484 	ether_addr_copy(search_claim.addr, addr);
2485 	search_claim.vid = vid;
2486 
2487 	claim = batadv_claim_hash_find(bat_priv, &search_claim);
2488 
2489 	/* If there is a claim and we are not owner of the claim,
2490 	 * return false.
2491 	 */
2492 	if (claim) {
2493 		if (!batadv_compare_eth(claim->backbone_gw->orig,
2494 					primary_if->net_dev->dev_addr))
2495 			ret = false;
2496 		batadv_claim_put(claim);
2497 	}
2498 
2499 	batadv_hardif_put(primary_if);
2500 	return ret;
2501 }
2502 #endif
2503