1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2007-2018  B.A.T.M.A.N. contributors:
3  *
4  * Marek Lindner, Simon Wunderlich
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of version 2 of the GNU General Public
8  * License as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
17  */
18 
19 #include "hard-interface.h"
20 #include "main.h"
21 
22 #include <linux/atomic.h>
23 #include <linux/bug.h>
24 #include <linux/byteorder/generic.h>
25 #include <linux/errno.h>
26 #include <linux/gfp.h>
27 #include <linux/if.h>
28 #include <linux/if_arp.h>
29 #include <linux/if_ether.h>
30 #include <linux/kernel.h>
31 #include <linux/kref.h>
32 #include <linux/list.h>
33 #include <linux/netdevice.h>
34 #include <linux/printk.h>
35 #include <linux/rculist.h>
36 #include <linux/rtnetlink.h>
37 #include <linux/slab.h>
38 #include <linux/spinlock.h>
39 #include <net/net_namespace.h>
40 #include <net/rtnetlink.h>
41 #include <uapi/linux/batadv_packet.h>
42 
43 #include "bat_v.h"
44 #include "bridge_loop_avoidance.h"
45 #include "debugfs.h"
46 #include "distributed-arp-table.h"
47 #include "gateway_client.h"
48 #include "log.h"
49 #include "originator.h"
50 #include "send.h"
51 #include "soft-interface.h"
52 #include "sysfs.h"
53 #include "translation-table.h"
54 
55 /**
56  * batadv_hardif_release() - release hard interface from lists and queue for
57  *  free after rcu grace period
58  * @ref: kref pointer of the hard interface
59  */
60 void batadv_hardif_release(struct kref *ref)
61 {
62 	struct batadv_hard_iface *hard_iface;
63 
64 	hard_iface = container_of(ref, struct batadv_hard_iface, refcount);
65 	dev_put(hard_iface->net_dev);
66 
67 	kfree_rcu(hard_iface, rcu);
68 }
69 
70 /**
71  * batadv_hardif_get_by_netdev() - Get hard interface object of a net_device
72  * @net_dev: net_device to search for
73  *
74  * Return: batadv_hard_iface of net_dev (with increased refcnt), NULL on errors
75  */
76 struct batadv_hard_iface *
77 batadv_hardif_get_by_netdev(const struct net_device *net_dev)
78 {
79 	struct batadv_hard_iface *hard_iface;
80 
81 	rcu_read_lock();
82 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
83 		if (hard_iface->net_dev == net_dev &&
84 		    kref_get_unless_zero(&hard_iface->refcount))
85 			goto out;
86 	}
87 
88 	hard_iface = NULL;
89 
90 out:
91 	rcu_read_unlock();
92 	return hard_iface;
93 }
94 
95 /**
96  * batadv_getlink_net() - return link net namespace (of use fallback)
97  * @netdev: net_device to check
98  * @fallback_net: return in case get_link_net is not available for @netdev
99  *
100  * Return: result of rtnl_link_ops->get_link_net or @fallback_net
101  */
102 static struct net *batadv_getlink_net(const struct net_device *netdev,
103 				      struct net *fallback_net)
104 {
105 	if (!netdev->rtnl_link_ops)
106 		return fallback_net;
107 
108 	if (!netdev->rtnl_link_ops->get_link_net)
109 		return fallback_net;
110 
111 	return netdev->rtnl_link_ops->get_link_net(netdev);
112 }
113 
114 /**
115  * batadv_mutual_parents() - check if two devices are each others parent
116  * @dev1: 1st net dev
117  * @net1: 1st devices netns
118  * @dev2: 2nd net dev
119  * @net2: 2nd devices netns
120  *
121  * veth devices come in pairs and each is the parent of the other!
122  *
123  * Return: true if the devices are each others parent, otherwise false
124  */
125 static bool batadv_mutual_parents(const struct net_device *dev1,
126 				  struct net *net1,
127 				  const struct net_device *dev2,
128 				  struct net *net2)
129 {
130 	int dev1_parent_iflink = dev_get_iflink(dev1);
131 	int dev2_parent_iflink = dev_get_iflink(dev2);
132 	const struct net *dev1_parent_net;
133 	const struct net *dev2_parent_net;
134 
135 	dev1_parent_net = batadv_getlink_net(dev1, net1);
136 	dev2_parent_net = batadv_getlink_net(dev2, net2);
137 
138 	if (!dev1_parent_iflink || !dev2_parent_iflink)
139 		return false;
140 
141 	return (dev1_parent_iflink == dev2->ifindex) &&
142 	       (dev2_parent_iflink == dev1->ifindex) &&
143 	       net_eq(dev1_parent_net, net2) &&
144 	       net_eq(dev2_parent_net, net1);
145 }
146 
147 /**
148  * batadv_is_on_batman_iface() - check if a device is a batman iface descendant
149  * @net_dev: the device to check
150  *
151  * If the user creates any virtual device on top of a batman-adv interface, it
152  * is important to prevent this new interface to be used to create a new mesh
153  * network (this behaviour would lead to a batman-over-batman configuration).
154  * This function recursively checks all the fathers of the device passed as
155  * argument looking for a batman-adv soft interface.
156  *
157  * Return: true if the device is descendant of a batman-adv mesh interface (or
158  * if it is a batman-adv interface itself), false otherwise
159  */
160 static bool batadv_is_on_batman_iface(const struct net_device *net_dev)
161 {
162 	struct net *net = dev_net(net_dev);
163 	struct net_device *parent_dev;
164 	struct net *parent_net;
165 	bool ret;
166 
167 	/* check if this is a batman-adv mesh interface */
168 	if (batadv_softif_is_valid(net_dev))
169 		return true;
170 
171 	/* no more parents..stop recursion */
172 	if (dev_get_iflink(net_dev) == 0 ||
173 	    dev_get_iflink(net_dev) == net_dev->ifindex)
174 		return false;
175 
176 	parent_net = batadv_getlink_net(net_dev, net);
177 
178 	/* recurse over the parent device */
179 	parent_dev = __dev_get_by_index((struct net *)parent_net,
180 					dev_get_iflink(net_dev));
181 	/* if we got a NULL parent_dev there is something broken.. */
182 	if (WARN(!parent_dev, "Cannot find parent device"))
183 		return false;
184 
185 	if (batadv_mutual_parents(net_dev, net, parent_dev, parent_net))
186 		return false;
187 
188 	ret = batadv_is_on_batman_iface(parent_dev);
189 
190 	return ret;
191 }
192 
193 static bool batadv_is_valid_iface(const struct net_device *net_dev)
194 {
195 	if (net_dev->flags & IFF_LOOPBACK)
196 		return false;
197 
198 	if (net_dev->type != ARPHRD_ETHER)
199 		return false;
200 
201 	if (net_dev->addr_len != ETH_ALEN)
202 		return false;
203 
204 	/* no batman over batman */
205 	if (batadv_is_on_batman_iface(net_dev))
206 		return false;
207 
208 	return true;
209 }
210 
211 /**
212  * batadv_get_real_netdevice() - check if the given netdev struct is a virtual
213  *  interface on top of another 'real' interface
214  * @netdev: the device to check
215  *
216  * Callers must hold the rtnl semaphore. You may want batadv_get_real_netdev()
217  * instead of this.
218  *
219  * Return: the 'real' net device or the original net device and NULL in case
220  *  of an error.
221  */
222 static struct net_device *batadv_get_real_netdevice(struct net_device *netdev)
223 {
224 	struct batadv_hard_iface *hard_iface = NULL;
225 	struct net_device *real_netdev = NULL;
226 	struct net *real_net;
227 	struct net *net;
228 	int ifindex;
229 
230 	ASSERT_RTNL();
231 
232 	if (!netdev)
233 		return NULL;
234 
235 	if (netdev->ifindex == dev_get_iflink(netdev)) {
236 		dev_hold(netdev);
237 		return netdev;
238 	}
239 
240 	hard_iface = batadv_hardif_get_by_netdev(netdev);
241 	if (!hard_iface || !hard_iface->soft_iface)
242 		goto out;
243 
244 	net = dev_net(hard_iface->soft_iface);
245 	ifindex = dev_get_iflink(netdev);
246 	real_net = batadv_getlink_net(netdev, net);
247 	real_netdev = dev_get_by_index(real_net, ifindex);
248 
249 out:
250 	if (hard_iface)
251 		batadv_hardif_put(hard_iface);
252 	return real_netdev;
253 }
254 
255 /**
256  * batadv_get_real_netdev() - check if the given net_device struct is a virtual
257  *  interface on top of another 'real' interface
258  * @net_device: the device to check
259  *
260  * Return: the 'real' net device or the original net device and NULL in case
261  *  of an error.
262  */
263 struct net_device *batadv_get_real_netdev(struct net_device *net_device)
264 {
265 	struct net_device *real_netdev;
266 
267 	rtnl_lock();
268 	real_netdev = batadv_get_real_netdevice(net_device);
269 	rtnl_unlock();
270 
271 	return real_netdev;
272 }
273 
274 /**
275  * batadv_is_wext_netdev() - check if the given net_device struct is a
276  *  wext wifi interface
277  * @net_device: the device to check
278  *
279  * Return: true if the net device is a wext wireless device, false
280  *  otherwise.
281  */
282 static bool batadv_is_wext_netdev(struct net_device *net_device)
283 {
284 	if (!net_device)
285 		return false;
286 
287 #ifdef CONFIG_WIRELESS_EXT
288 	/* pre-cfg80211 drivers have to implement WEXT, so it is possible to
289 	 * check for wireless_handlers != NULL
290 	 */
291 	if (net_device->wireless_handlers)
292 		return true;
293 #endif
294 
295 	return false;
296 }
297 
298 /**
299  * batadv_is_cfg80211_netdev() - check if the given net_device struct is a
300  *  cfg80211 wifi interface
301  * @net_device: the device to check
302  *
303  * Return: true if the net device is a cfg80211 wireless device, false
304  *  otherwise.
305  */
306 static bool batadv_is_cfg80211_netdev(struct net_device *net_device)
307 {
308 	if (!net_device)
309 		return false;
310 
311 	/* cfg80211 drivers have to set ieee80211_ptr */
312 	if (net_device->ieee80211_ptr)
313 		return true;
314 
315 	return false;
316 }
317 
318 /**
319  * batadv_wifi_flags_evaluate() - calculate wifi flags for net_device
320  * @net_device: the device to check
321  *
322  * Return: batadv_hard_iface_wifi_flags flags of the device
323  */
324 static u32 batadv_wifi_flags_evaluate(struct net_device *net_device)
325 {
326 	u32 wifi_flags = 0;
327 	struct net_device *real_netdev;
328 
329 	if (batadv_is_wext_netdev(net_device))
330 		wifi_flags |= BATADV_HARDIF_WIFI_WEXT_DIRECT;
331 
332 	if (batadv_is_cfg80211_netdev(net_device))
333 		wifi_flags |= BATADV_HARDIF_WIFI_CFG80211_DIRECT;
334 
335 	real_netdev = batadv_get_real_netdevice(net_device);
336 	if (!real_netdev)
337 		return wifi_flags;
338 
339 	if (real_netdev == net_device)
340 		goto out;
341 
342 	if (batadv_is_wext_netdev(real_netdev))
343 		wifi_flags |= BATADV_HARDIF_WIFI_WEXT_INDIRECT;
344 
345 	if (batadv_is_cfg80211_netdev(real_netdev))
346 		wifi_flags |= BATADV_HARDIF_WIFI_CFG80211_INDIRECT;
347 
348 out:
349 	dev_put(real_netdev);
350 	return wifi_flags;
351 }
352 
353 /**
354  * batadv_is_cfg80211_hardif() - check if the given hardif is a cfg80211 wifi
355  *  interface
356  * @hard_iface: the device to check
357  *
358  * Return: true if the net device is a cfg80211 wireless device, false
359  *  otherwise.
360  */
361 bool batadv_is_cfg80211_hardif(struct batadv_hard_iface *hard_iface)
362 {
363 	u32 allowed_flags = 0;
364 
365 	allowed_flags |= BATADV_HARDIF_WIFI_CFG80211_DIRECT;
366 	allowed_flags |= BATADV_HARDIF_WIFI_CFG80211_INDIRECT;
367 
368 	return !!(hard_iface->wifi_flags & allowed_flags);
369 }
370 
371 /**
372  * batadv_is_wifi_hardif() - check if the given hardif is a wifi interface
373  * @hard_iface: the device to check
374  *
375  * Return: true if the net device is a 802.11 wireless device, false otherwise.
376  */
377 bool batadv_is_wifi_hardif(struct batadv_hard_iface *hard_iface)
378 {
379 	if (!hard_iface)
380 		return false;
381 
382 	return hard_iface->wifi_flags != 0;
383 }
384 
385 /**
386  * batadv_hardif_no_broadcast() - check whether (re)broadcast is necessary
387  * @if_outgoing: the outgoing interface checked and considered for (re)broadcast
388  * @orig_addr: the originator of this packet
389  * @orig_neigh: originator address of the forwarder we just got the packet from
390  *  (NULL if we originated)
391  *
392  * Checks whether a packet needs to be (re)broadcasted on the given interface.
393  *
394  * Return:
395  *	BATADV_HARDIF_BCAST_NORECIPIENT: No neighbor on interface
396  *	BATADV_HARDIF_BCAST_DUPFWD: Just one neighbor, but it is the forwarder
397  *	BATADV_HARDIF_BCAST_DUPORIG: Just one neighbor, but it is the originator
398  *	BATADV_HARDIF_BCAST_OK: Several neighbors, must broadcast
399  */
400 int batadv_hardif_no_broadcast(struct batadv_hard_iface *if_outgoing,
401 			       u8 *orig_addr, u8 *orig_neigh)
402 {
403 	struct batadv_hardif_neigh_node *hardif_neigh;
404 	struct hlist_node *first;
405 	int ret = BATADV_HARDIF_BCAST_OK;
406 
407 	rcu_read_lock();
408 
409 	/* 0 neighbors -> no (re)broadcast */
410 	first = rcu_dereference(hlist_first_rcu(&if_outgoing->neigh_list));
411 	if (!first) {
412 		ret = BATADV_HARDIF_BCAST_NORECIPIENT;
413 		goto out;
414 	}
415 
416 	/* >1 neighbors -> (re)brodcast */
417 	if (rcu_dereference(hlist_next_rcu(first)))
418 		goto out;
419 
420 	hardif_neigh = hlist_entry(first, struct batadv_hardif_neigh_node,
421 				   list);
422 
423 	/* 1 neighbor, is the originator -> no rebroadcast */
424 	if (orig_addr && batadv_compare_eth(hardif_neigh->orig, orig_addr)) {
425 		ret = BATADV_HARDIF_BCAST_DUPORIG;
426 	/* 1 neighbor, is the one we received from -> no rebroadcast */
427 	} else if (orig_neigh &&
428 		   batadv_compare_eth(hardif_neigh->orig, orig_neigh)) {
429 		ret = BATADV_HARDIF_BCAST_DUPFWD;
430 	}
431 
432 out:
433 	rcu_read_unlock();
434 	return ret;
435 }
436 
437 static struct batadv_hard_iface *
438 batadv_hardif_get_active(const struct net_device *soft_iface)
439 {
440 	struct batadv_hard_iface *hard_iface;
441 
442 	rcu_read_lock();
443 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
444 		if (hard_iface->soft_iface != soft_iface)
445 			continue;
446 
447 		if (hard_iface->if_status == BATADV_IF_ACTIVE &&
448 		    kref_get_unless_zero(&hard_iface->refcount))
449 			goto out;
450 	}
451 
452 	hard_iface = NULL;
453 
454 out:
455 	rcu_read_unlock();
456 	return hard_iface;
457 }
458 
459 static void batadv_primary_if_update_addr(struct batadv_priv *bat_priv,
460 					  struct batadv_hard_iface *oldif)
461 {
462 	struct batadv_hard_iface *primary_if;
463 
464 	primary_if = batadv_primary_if_get_selected(bat_priv);
465 	if (!primary_if)
466 		goto out;
467 
468 	batadv_dat_init_own_addr(bat_priv, primary_if);
469 	batadv_bla_update_orig_address(bat_priv, primary_if, oldif);
470 out:
471 	if (primary_if)
472 		batadv_hardif_put(primary_if);
473 }
474 
475 static void batadv_primary_if_select(struct batadv_priv *bat_priv,
476 				     struct batadv_hard_iface *new_hard_iface)
477 {
478 	struct batadv_hard_iface *curr_hard_iface;
479 
480 	ASSERT_RTNL();
481 
482 	if (new_hard_iface)
483 		kref_get(&new_hard_iface->refcount);
484 
485 	curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
486 	rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);
487 
488 	if (!new_hard_iface)
489 		goto out;
490 
491 	bat_priv->algo_ops->iface.primary_set(new_hard_iface);
492 	batadv_primary_if_update_addr(bat_priv, curr_hard_iface);
493 
494 out:
495 	if (curr_hard_iface)
496 		batadv_hardif_put(curr_hard_iface);
497 }
498 
499 static bool
500 batadv_hardif_is_iface_up(const struct batadv_hard_iface *hard_iface)
501 {
502 	if (hard_iface->net_dev->flags & IFF_UP)
503 		return true;
504 
505 	return false;
506 }
507 
508 static void batadv_check_known_mac_addr(const struct net_device *net_dev)
509 {
510 	const struct batadv_hard_iface *hard_iface;
511 
512 	rcu_read_lock();
513 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
514 		if (hard_iface->if_status != BATADV_IF_ACTIVE &&
515 		    hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED)
516 			continue;
517 
518 		if (hard_iface->net_dev == net_dev)
519 			continue;
520 
521 		if (!batadv_compare_eth(hard_iface->net_dev->dev_addr,
522 					net_dev->dev_addr))
523 			continue;
524 
525 		pr_warn("The newly added mac address (%pM) already exists on: %s\n",
526 			net_dev->dev_addr, hard_iface->net_dev->name);
527 		pr_warn("It is strongly recommended to keep mac addresses unique to avoid problems!\n");
528 	}
529 	rcu_read_unlock();
530 }
531 
532 /**
533  * batadv_hardif_recalc_extra_skbroom() - Recalculate skbuff extra head/tailroom
534  * @soft_iface: netdev struct of the mesh interface
535  */
536 static void batadv_hardif_recalc_extra_skbroom(struct net_device *soft_iface)
537 {
538 	const struct batadv_hard_iface *hard_iface;
539 	unsigned short lower_header_len = ETH_HLEN;
540 	unsigned short lower_headroom = 0;
541 	unsigned short lower_tailroom = 0;
542 	unsigned short needed_headroom;
543 
544 	rcu_read_lock();
545 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
546 		if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
547 			continue;
548 
549 		if (hard_iface->soft_iface != soft_iface)
550 			continue;
551 
552 		lower_header_len = max_t(unsigned short, lower_header_len,
553 					 hard_iface->net_dev->hard_header_len);
554 
555 		lower_headroom = max_t(unsigned short, lower_headroom,
556 				       hard_iface->net_dev->needed_headroom);
557 
558 		lower_tailroom = max_t(unsigned short, lower_tailroom,
559 				       hard_iface->net_dev->needed_tailroom);
560 	}
561 	rcu_read_unlock();
562 
563 	needed_headroom = lower_headroom + (lower_header_len - ETH_HLEN);
564 	needed_headroom += batadv_max_header_len();
565 
566 	soft_iface->needed_headroom = needed_headroom;
567 	soft_iface->needed_tailroom = lower_tailroom;
568 }
569 
570 /**
571  * batadv_hardif_min_mtu() - Calculate maximum MTU for soft interface
572  * @soft_iface: netdev struct of the soft interface
573  *
574  * Return: MTU for the soft-interface (limited by the minimal MTU of all active
575  *  slave interfaces)
576  */
577 int batadv_hardif_min_mtu(struct net_device *soft_iface)
578 {
579 	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
580 	const struct batadv_hard_iface *hard_iface;
581 	int min_mtu = INT_MAX;
582 
583 	rcu_read_lock();
584 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
585 		if (hard_iface->if_status != BATADV_IF_ACTIVE &&
586 		    hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED)
587 			continue;
588 
589 		if (hard_iface->soft_iface != soft_iface)
590 			continue;
591 
592 		min_mtu = min_t(int, hard_iface->net_dev->mtu, min_mtu);
593 	}
594 	rcu_read_unlock();
595 
596 	if (atomic_read(&bat_priv->fragmentation) == 0)
597 		goto out;
598 
599 	/* with fragmentation enabled the maximum size of internally generated
600 	 * packets such as translation table exchanges or tvlv containers, etc
601 	 * has to be calculated
602 	 */
603 	min_mtu = min_t(int, min_mtu, BATADV_FRAG_MAX_FRAG_SIZE);
604 	min_mtu -= sizeof(struct batadv_frag_packet);
605 	min_mtu *= BATADV_FRAG_MAX_FRAGMENTS;
606 
607 out:
608 	/* report to the other components the maximum amount of bytes that
609 	 * batman-adv can send over the wire (without considering the payload
610 	 * overhead). For example, this value is used by TT to compute the
611 	 * maximum local table table size
612 	 */
613 	atomic_set(&bat_priv->packet_size_max, min_mtu);
614 
615 	/* the real soft-interface MTU is computed by removing the payload
616 	 * overhead from the maximum amount of bytes that was just computed.
617 	 *
618 	 * However batman-adv does not support MTUs bigger than ETH_DATA_LEN
619 	 */
620 	return min_t(int, min_mtu - batadv_max_header_len(), ETH_DATA_LEN);
621 }
622 
623 /**
624  * batadv_update_min_mtu() - Adjusts the MTU if a new interface with a smaller
625  *  MTU appeared
626  * @soft_iface: netdev struct of the soft interface
627  */
628 void batadv_update_min_mtu(struct net_device *soft_iface)
629 {
630 	soft_iface->mtu = batadv_hardif_min_mtu(soft_iface);
631 
632 	/* Check if the local translate table should be cleaned up to match a
633 	 * new (and smaller) MTU.
634 	 */
635 	batadv_tt_local_resize_to_mtu(soft_iface);
636 }
637 
638 static void
639 batadv_hardif_activate_interface(struct batadv_hard_iface *hard_iface)
640 {
641 	struct batadv_priv *bat_priv;
642 	struct batadv_hard_iface *primary_if = NULL;
643 
644 	if (hard_iface->if_status != BATADV_IF_INACTIVE)
645 		goto out;
646 
647 	bat_priv = netdev_priv(hard_iface->soft_iface);
648 
649 	bat_priv->algo_ops->iface.update_mac(hard_iface);
650 	hard_iface->if_status = BATADV_IF_TO_BE_ACTIVATED;
651 
652 	/* the first active interface becomes our primary interface or
653 	 * the next active interface after the old primary interface was removed
654 	 */
655 	primary_if = batadv_primary_if_get_selected(bat_priv);
656 	if (!primary_if)
657 		batadv_primary_if_select(bat_priv, hard_iface);
658 
659 	batadv_info(hard_iface->soft_iface, "Interface activated: %s\n",
660 		    hard_iface->net_dev->name);
661 
662 	batadv_update_min_mtu(hard_iface->soft_iface);
663 
664 	if (bat_priv->algo_ops->iface.activate)
665 		bat_priv->algo_ops->iface.activate(hard_iface);
666 
667 out:
668 	if (primary_if)
669 		batadv_hardif_put(primary_if);
670 }
671 
672 static void
673 batadv_hardif_deactivate_interface(struct batadv_hard_iface *hard_iface)
674 {
675 	if (hard_iface->if_status != BATADV_IF_ACTIVE &&
676 	    hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED)
677 		return;
678 
679 	hard_iface->if_status = BATADV_IF_INACTIVE;
680 
681 	batadv_info(hard_iface->soft_iface, "Interface deactivated: %s\n",
682 		    hard_iface->net_dev->name);
683 
684 	batadv_update_min_mtu(hard_iface->soft_iface);
685 }
686 
687 /**
688  * batadv_master_del_slave() - remove hard_iface from the current master iface
689  * @slave: the interface enslaved in another master
690  * @master: the master from which slave has to be removed
691  *
692  * Invoke ndo_del_slave on master passing slave as argument. In this way slave
693  * is free'd and master can correctly change its internal state.
694  *
695  * Return: 0 on success, a negative value representing the error otherwise
696  */
697 static int batadv_master_del_slave(struct batadv_hard_iface *slave,
698 				   struct net_device *master)
699 {
700 	int ret;
701 
702 	if (!master)
703 		return 0;
704 
705 	ret = -EBUSY;
706 	if (master->netdev_ops->ndo_del_slave)
707 		ret = master->netdev_ops->ndo_del_slave(master, slave->net_dev);
708 
709 	return ret;
710 }
711 
712 /**
713  * batadv_hardif_enable_interface() - Enslave hard interface to soft interface
714  * @hard_iface: hard interface to add to soft interface
715  * @net: the applicable net namespace
716  * @iface_name: name of the soft interface
717  *
718  * Return: 0 on success or negative error number in case of failure
719  */
720 int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
721 				   struct net *net, const char *iface_name)
722 {
723 	struct batadv_priv *bat_priv;
724 	struct net_device *soft_iface, *master;
725 	__be16 ethertype = htons(ETH_P_BATMAN);
726 	int max_header_len = batadv_max_header_len();
727 	int ret;
728 
729 	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
730 		goto out;
731 
732 	kref_get(&hard_iface->refcount);
733 
734 	soft_iface = dev_get_by_name(net, iface_name);
735 
736 	if (!soft_iface) {
737 		soft_iface = batadv_softif_create(net, iface_name);
738 
739 		if (!soft_iface) {
740 			ret = -ENOMEM;
741 			goto err;
742 		}
743 
744 		/* dev_get_by_name() increases the reference counter for us */
745 		dev_hold(soft_iface);
746 	}
747 
748 	if (!batadv_softif_is_valid(soft_iface)) {
749 		pr_err("Can't create batman mesh interface %s: already exists as regular interface\n",
750 		       soft_iface->name);
751 		ret = -EINVAL;
752 		goto err_dev;
753 	}
754 
755 	/* check if the interface is enslaved in another virtual one and
756 	 * in that case unlink it first
757 	 */
758 	master = netdev_master_upper_dev_get(hard_iface->net_dev);
759 	ret = batadv_master_del_slave(hard_iface, master);
760 	if (ret)
761 		goto err_dev;
762 
763 	hard_iface->soft_iface = soft_iface;
764 	bat_priv = netdev_priv(hard_iface->soft_iface);
765 
766 	if (bat_priv->num_ifaces >= UINT_MAX) {
767 		ret = -ENOSPC;
768 		goto err_dev;
769 	}
770 
771 	ret = netdev_master_upper_dev_link(hard_iface->net_dev,
772 					   soft_iface, NULL, NULL, NULL);
773 	if (ret)
774 		goto err_dev;
775 
776 	ret = bat_priv->algo_ops->iface.enable(hard_iface);
777 	if (ret < 0)
778 		goto err_upper;
779 
780 	hard_iface->if_num = bat_priv->num_ifaces;
781 	bat_priv->num_ifaces++;
782 	hard_iface->if_status = BATADV_IF_INACTIVE;
783 	ret = batadv_orig_hash_add_if(hard_iface, bat_priv->num_ifaces);
784 	if (ret < 0) {
785 		bat_priv->algo_ops->iface.disable(hard_iface);
786 		bat_priv->num_ifaces--;
787 		hard_iface->if_status = BATADV_IF_NOT_IN_USE;
788 		goto err_upper;
789 	}
790 
791 	kref_get(&hard_iface->refcount);
792 	hard_iface->batman_adv_ptype.type = ethertype;
793 	hard_iface->batman_adv_ptype.func = batadv_batman_skb_recv;
794 	hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
795 	dev_add_pack(&hard_iface->batman_adv_ptype);
796 
797 	batadv_info(hard_iface->soft_iface, "Adding interface: %s\n",
798 		    hard_iface->net_dev->name);
799 
800 	if (atomic_read(&bat_priv->fragmentation) &&
801 	    hard_iface->net_dev->mtu < ETH_DATA_LEN + max_header_len)
802 		batadv_info(hard_iface->soft_iface,
803 			    "The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to %i would solve the problem.\n",
804 			    hard_iface->net_dev->name, hard_iface->net_dev->mtu,
805 			    ETH_DATA_LEN + max_header_len);
806 
807 	if (!atomic_read(&bat_priv->fragmentation) &&
808 	    hard_iface->net_dev->mtu < ETH_DATA_LEN + max_header_len)
809 		batadv_info(hard_iface->soft_iface,
810 			    "The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. If you experience problems getting traffic through try increasing the MTU to %i.\n",
811 			    hard_iface->net_dev->name, hard_iface->net_dev->mtu,
812 			    ETH_DATA_LEN + max_header_len);
813 
814 	if (batadv_hardif_is_iface_up(hard_iface))
815 		batadv_hardif_activate_interface(hard_iface);
816 	else
817 		batadv_err(hard_iface->soft_iface,
818 			   "Not using interface %s (retrying later): interface not active\n",
819 			   hard_iface->net_dev->name);
820 
821 	batadv_hardif_recalc_extra_skbroom(soft_iface);
822 
823 out:
824 	return 0;
825 
826 err_upper:
827 	netdev_upper_dev_unlink(hard_iface->net_dev, soft_iface);
828 err_dev:
829 	hard_iface->soft_iface = NULL;
830 	dev_put(soft_iface);
831 err:
832 	batadv_hardif_put(hard_iface);
833 	return ret;
834 }
835 
836 /**
837  * batadv_hardif_disable_interface() - Remove hard interface from soft interface
838  * @hard_iface: hard interface to be removed
839  * @autodel: whether to delete soft interface when it doesn't contain any other
840  *  slave interfaces
841  */
842 void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface,
843 				     enum batadv_hard_if_cleanup autodel)
844 {
845 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
846 	struct batadv_hard_iface *primary_if = NULL;
847 
848 	batadv_hardif_deactivate_interface(hard_iface);
849 
850 	if (hard_iface->if_status != BATADV_IF_INACTIVE)
851 		goto out;
852 
853 	batadv_info(hard_iface->soft_iface, "Removing interface: %s\n",
854 		    hard_iface->net_dev->name);
855 	dev_remove_pack(&hard_iface->batman_adv_ptype);
856 	batadv_hardif_put(hard_iface);
857 
858 	bat_priv->num_ifaces--;
859 	batadv_orig_hash_del_if(hard_iface, bat_priv->num_ifaces);
860 
861 	primary_if = batadv_primary_if_get_selected(bat_priv);
862 	if (hard_iface == primary_if) {
863 		struct batadv_hard_iface *new_if;
864 
865 		new_if = batadv_hardif_get_active(hard_iface->soft_iface);
866 		batadv_primary_if_select(bat_priv, new_if);
867 
868 		if (new_if)
869 			batadv_hardif_put(new_if);
870 	}
871 
872 	bat_priv->algo_ops->iface.disable(hard_iface);
873 	hard_iface->if_status = BATADV_IF_NOT_IN_USE;
874 
875 	/* delete all references to this hard_iface */
876 	batadv_purge_orig_ref(bat_priv);
877 	batadv_purge_outstanding_packets(bat_priv, hard_iface);
878 	dev_put(hard_iface->soft_iface);
879 
880 	netdev_upper_dev_unlink(hard_iface->net_dev, hard_iface->soft_iface);
881 	batadv_hardif_recalc_extra_skbroom(hard_iface->soft_iface);
882 
883 	/* nobody uses this interface anymore */
884 	if (bat_priv->num_ifaces == 0) {
885 		batadv_gw_check_client_stop(bat_priv);
886 
887 		if (autodel == BATADV_IF_CLEANUP_AUTO)
888 			batadv_softif_destroy_sysfs(hard_iface->soft_iface);
889 	}
890 
891 	hard_iface->soft_iface = NULL;
892 	batadv_hardif_put(hard_iface);
893 
894 out:
895 	if (primary_if)
896 		batadv_hardif_put(primary_if);
897 }
898 
899 static struct batadv_hard_iface *
900 batadv_hardif_add_interface(struct net_device *net_dev)
901 {
902 	struct batadv_hard_iface *hard_iface;
903 	int ret;
904 
905 	ASSERT_RTNL();
906 
907 	if (!batadv_is_valid_iface(net_dev))
908 		goto out;
909 
910 	dev_hold(net_dev);
911 
912 	hard_iface = kzalloc(sizeof(*hard_iface), GFP_ATOMIC);
913 	if (!hard_iface)
914 		goto release_dev;
915 
916 	ret = batadv_sysfs_add_hardif(&hard_iface->hardif_obj, net_dev);
917 	if (ret)
918 		goto free_if;
919 
920 	hard_iface->if_num = 0;
921 	hard_iface->net_dev = net_dev;
922 	hard_iface->soft_iface = NULL;
923 	hard_iface->if_status = BATADV_IF_NOT_IN_USE;
924 
925 	ret = batadv_debugfs_add_hardif(hard_iface);
926 	if (ret)
927 		goto free_sysfs;
928 
929 	INIT_LIST_HEAD(&hard_iface->list);
930 	INIT_HLIST_HEAD(&hard_iface->neigh_list);
931 
932 	spin_lock_init(&hard_iface->neigh_list_lock);
933 	kref_init(&hard_iface->refcount);
934 
935 	hard_iface->num_bcasts = BATADV_NUM_BCASTS_DEFAULT;
936 	hard_iface->wifi_flags = batadv_wifi_flags_evaluate(net_dev);
937 	if (batadv_is_wifi_hardif(hard_iface))
938 		hard_iface->num_bcasts = BATADV_NUM_BCASTS_WIRELESS;
939 
940 	batadv_v_hardif_init(hard_iface);
941 
942 	batadv_check_known_mac_addr(hard_iface->net_dev);
943 	kref_get(&hard_iface->refcount);
944 	list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);
945 
946 	return hard_iface;
947 
948 free_sysfs:
949 	batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
950 free_if:
951 	kfree(hard_iface);
952 release_dev:
953 	dev_put(net_dev);
954 out:
955 	return NULL;
956 }
957 
958 static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface)
959 {
960 	ASSERT_RTNL();
961 
962 	/* first deactivate interface */
963 	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
964 		batadv_hardif_disable_interface(hard_iface,
965 						BATADV_IF_CLEANUP_KEEP);
966 
967 	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
968 		return;
969 
970 	hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;
971 	batadv_debugfs_del_hardif(hard_iface);
972 	batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
973 	batadv_hardif_put(hard_iface);
974 }
975 
976 /**
977  * batadv_hardif_remove_interfaces() - Remove all hard interfaces
978  */
979 void batadv_hardif_remove_interfaces(void)
980 {
981 	struct batadv_hard_iface *hard_iface, *hard_iface_tmp;
982 
983 	rtnl_lock();
984 	list_for_each_entry_safe(hard_iface, hard_iface_tmp,
985 				 &batadv_hardif_list, list) {
986 		list_del_rcu(&hard_iface->list);
987 		batadv_hardif_remove_interface(hard_iface);
988 	}
989 	rtnl_unlock();
990 }
991 
992 static int batadv_hard_if_event(struct notifier_block *this,
993 				unsigned long event, void *ptr)
994 {
995 	struct net_device *net_dev = netdev_notifier_info_to_dev(ptr);
996 	struct batadv_hard_iface *hard_iface;
997 	struct batadv_hard_iface *primary_if = NULL;
998 	struct batadv_priv *bat_priv;
999 
1000 	if (batadv_softif_is_valid(net_dev) && event == NETDEV_REGISTER) {
1001 		batadv_sysfs_add_meshif(net_dev);
1002 		bat_priv = netdev_priv(net_dev);
1003 		batadv_softif_create_vlan(bat_priv, BATADV_NO_FLAGS);
1004 		return NOTIFY_DONE;
1005 	}
1006 
1007 	hard_iface = batadv_hardif_get_by_netdev(net_dev);
1008 	if (!hard_iface && (event == NETDEV_REGISTER ||
1009 			    event == NETDEV_POST_TYPE_CHANGE))
1010 		hard_iface = batadv_hardif_add_interface(net_dev);
1011 
1012 	if (!hard_iface)
1013 		goto out;
1014 
1015 	switch (event) {
1016 	case NETDEV_UP:
1017 		batadv_hardif_activate_interface(hard_iface);
1018 		break;
1019 	case NETDEV_GOING_DOWN:
1020 	case NETDEV_DOWN:
1021 		batadv_hardif_deactivate_interface(hard_iface);
1022 		break;
1023 	case NETDEV_UNREGISTER:
1024 	case NETDEV_PRE_TYPE_CHANGE:
1025 		list_del_rcu(&hard_iface->list);
1026 
1027 		batadv_hardif_remove_interface(hard_iface);
1028 		break;
1029 	case NETDEV_CHANGEMTU:
1030 		if (hard_iface->soft_iface)
1031 			batadv_update_min_mtu(hard_iface->soft_iface);
1032 		break;
1033 	case NETDEV_CHANGEADDR:
1034 		if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
1035 			goto hardif_put;
1036 
1037 		batadv_check_known_mac_addr(hard_iface->net_dev);
1038 
1039 		bat_priv = netdev_priv(hard_iface->soft_iface);
1040 		bat_priv->algo_ops->iface.update_mac(hard_iface);
1041 
1042 		primary_if = batadv_primary_if_get_selected(bat_priv);
1043 		if (!primary_if)
1044 			goto hardif_put;
1045 
1046 		if (hard_iface == primary_if)
1047 			batadv_primary_if_update_addr(bat_priv, NULL);
1048 		break;
1049 	case NETDEV_CHANGEUPPER:
1050 		hard_iface->wifi_flags = batadv_wifi_flags_evaluate(net_dev);
1051 		if (batadv_is_wifi_hardif(hard_iface))
1052 			hard_iface->num_bcasts = BATADV_NUM_BCASTS_WIRELESS;
1053 		break;
1054 	default:
1055 		break;
1056 	}
1057 
1058 hardif_put:
1059 	batadv_hardif_put(hard_iface);
1060 out:
1061 	if (primary_if)
1062 		batadv_hardif_put(primary_if);
1063 	return NOTIFY_DONE;
1064 }
1065 
1066 struct notifier_block batadv_hard_if_notifier = {
1067 	.notifier_call = batadv_hard_if_event,
1068 };
1069