1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) B.A.T.M.A.N. contributors:
3  *
4  * Marek Lindner, Simon Wunderlich
5  */
6 
7 #include "hard-interface.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/errno.h>
15 #include <linux/gfp.h>
16 #include <linux/if.h>
17 #include <linux/if_arp.h>
18 #include <linux/if_ether.h>
19 #include <linux/kref.h>
20 #include <linux/limits.h>
21 #include <linux/list.h>
22 #include <linux/minmax.h>
23 #include <linux/mutex.h>
24 #include <linux/netdevice.h>
25 #include <linux/printk.h>
26 #include <linux/rculist.h>
27 #include <linux/rtnetlink.h>
28 #include <linux/slab.h>
29 #include <linux/spinlock.h>
30 #include <net/net_namespace.h>
31 #include <net/rtnetlink.h>
32 #include <uapi/linux/batadv_packet.h>
33 
34 #include "bat_v.h"
35 #include "bridge_loop_avoidance.h"
36 #include "distributed-arp-table.h"
37 #include "gateway_client.h"
38 #include "log.h"
39 #include "originator.h"
40 #include "send.h"
41 #include "soft-interface.h"
42 #include "translation-table.h"
43 
44 /**
45  * batadv_hardif_release() - release hard interface from lists and queue for
46  *  free after rcu grace period
47  * @ref: kref pointer of the hard interface
48  */
batadv_hardif_release(struct kref * ref)49 void batadv_hardif_release(struct kref *ref)
50 {
51 	struct batadv_hard_iface *hard_iface;
52 
53 	hard_iface = container_of(ref, struct batadv_hard_iface, refcount);
54 	dev_put(hard_iface->net_dev);
55 
56 	kfree_rcu(hard_iface, rcu);
57 }
58 
59 /**
60  * batadv_hardif_get_by_netdev() - Get hard interface object of a net_device
61  * @net_dev: net_device to search for
62  *
63  * Return: batadv_hard_iface of net_dev (with increased refcnt), NULL on errors
64  */
65 struct batadv_hard_iface *
batadv_hardif_get_by_netdev(const struct net_device * net_dev)66 batadv_hardif_get_by_netdev(const struct net_device *net_dev)
67 {
68 	struct batadv_hard_iface *hard_iface;
69 
70 	rcu_read_lock();
71 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
72 		if (hard_iface->net_dev == net_dev &&
73 		    kref_get_unless_zero(&hard_iface->refcount))
74 			goto out;
75 	}
76 
77 	hard_iface = NULL;
78 
79 out:
80 	rcu_read_unlock();
81 	return hard_iface;
82 }
83 
84 /**
85  * batadv_getlink_net() - return link net namespace (of use fallback)
86  * @netdev: net_device to check
87  * @fallback_net: return in case get_link_net is not available for @netdev
88  *
89  * Return: result of rtnl_link_ops->get_link_net or @fallback_net
90  */
batadv_getlink_net(const struct net_device * netdev,struct net * fallback_net)91 static struct net *batadv_getlink_net(const struct net_device *netdev,
92 				      struct net *fallback_net)
93 {
94 	if (!netdev->rtnl_link_ops)
95 		return fallback_net;
96 
97 	if (!netdev->rtnl_link_ops->get_link_net)
98 		return fallback_net;
99 
100 	return netdev->rtnl_link_ops->get_link_net(netdev);
101 }
102 
103 /**
104  * batadv_mutual_parents() - check if two devices are each others parent
105  * @dev1: 1st net dev
106  * @net1: 1st devices netns
107  * @dev2: 2nd net dev
108  * @net2: 2nd devices netns
109  *
110  * veth devices come in pairs and each is the parent of the other!
111  *
112  * Return: true if the devices are each others parent, otherwise false
113  */
batadv_mutual_parents(const struct net_device * dev1,struct net * net1,const struct net_device * dev2,struct net * net2)114 static bool batadv_mutual_parents(const struct net_device *dev1,
115 				  struct net *net1,
116 				  const struct net_device *dev2,
117 				  struct net *net2)
118 {
119 	int dev1_parent_iflink = dev_get_iflink(dev1);
120 	int dev2_parent_iflink = dev_get_iflink(dev2);
121 	const struct net *dev1_parent_net;
122 	const struct net *dev2_parent_net;
123 
124 	dev1_parent_net = batadv_getlink_net(dev1, net1);
125 	dev2_parent_net = batadv_getlink_net(dev2, net2);
126 
127 	if (!dev1_parent_iflink || !dev2_parent_iflink)
128 		return false;
129 
130 	return (dev1_parent_iflink == dev2->ifindex) &&
131 	       (dev2_parent_iflink == dev1->ifindex) &&
132 	       net_eq(dev1_parent_net, net2) &&
133 	       net_eq(dev2_parent_net, net1);
134 }
135 
136 /**
137  * batadv_is_on_batman_iface() - check if a device is a batman iface descendant
138  * @net_dev: the device to check
139  *
140  * If the user creates any virtual device on top of a batman-adv interface, it
141  * is important to prevent this new interface from being used to create a new
142  * mesh network (this behaviour would lead to a batman-over-batman
143  * configuration). This function recursively checks all the fathers of the
144  * device passed as argument looking for a batman-adv soft interface.
145  *
146  * Return: true if the device is descendant of a batman-adv mesh interface (or
147  * if it is a batman-adv interface itself), false otherwise
148  */
batadv_is_on_batman_iface(const struct net_device * net_dev)149 static bool batadv_is_on_batman_iface(const struct net_device *net_dev)
150 {
151 	struct net *net = dev_net(net_dev);
152 	struct net_device *parent_dev;
153 	struct net *parent_net;
154 	int iflink;
155 	bool ret;
156 
157 	/* check if this is a batman-adv mesh interface */
158 	if (batadv_softif_is_valid(net_dev))
159 		return true;
160 
161 	iflink = dev_get_iflink(net_dev);
162 	if (iflink == 0)
163 		return false;
164 
165 	parent_net = batadv_getlink_net(net_dev, net);
166 
167 	/* iflink to itself, most likely physical device */
168 	if (net == parent_net && iflink == net_dev->ifindex)
169 		return false;
170 
171 	/* recurse over the parent device */
172 	parent_dev = __dev_get_by_index((struct net *)parent_net, iflink);
173 	if (!parent_dev) {
174 		pr_warn("Cannot find parent device. Skipping batadv-on-batadv check for %s\n",
175 			net_dev->name);
176 		return false;
177 	}
178 
179 	if (batadv_mutual_parents(net_dev, net, parent_dev, parent_net))
180 		return false;
181 
182 	ret = batadv_is_on_batman_iface(parent_dev);
183 
184 	return ret;
185 }
186 
batadv_is_valid_iface(const struct net_device * net_dev)187 static bool batadv_is_valid_iface(const struct net_device *net_dev)
188 {
189 	if (net_dev->flags & IFF_LOOPBACK)
190 		return false;
191 
192 	if (net_dev->type != ARPHRD_ETHER)
193 		return false;
194 
195 	if (net_dev->addr_len != ETH_ALEN)
196 		return false;
197 
198 	/* no batman over batman */
199 	if (batadv_is_on_batman_iface(net_dev))
200 		return false;
201 
202 	return true;
203 }
204 
205 /**
206  * batadv_get_real_netdevice() - check if the given netdev struct is a virtual
207  *  interface on top of another 'real' interface
208  * @netdev: the device to check
209  *
210  * Callers must hold the rtnl semaphore. You may want batadv_get_real_netdev()
211  * instead of this.
212  *
213  * Return: the 'real' net device or the original net device and NULL in case
214  *  of an error.
215  */
batadv_get_real_netdevice(struct net_device * netdev)216 static struct net_device *batadv_get_real_netdevice(struct net_device *netdev)
217 {
218 	struct batadv_hard_iface *hard_iface = NULL;
219 	struct net_device *real_netdev = NULL;
220 	struct net *real_net;
221 	struct net *net;
222 	int iflink;
223 
224 	ASSERT_RTNL();
225 
226 	if (!netdev)
227 		return NULL;
228 
229 	iflink = dev_get_iflink(netdev);
230 	if (iflink == 0) {
231 		dev_hold(netdev);
232 		return netdev;
233 	}
234 
235 	hard_iface = batadv_hardif_get_by_netdev(netdev);
236 	if (!hard_iface || !hard_iface->soft_iface)
237 		goto out;
238 
239 	net = dev_net(hard_iface->soft_iface);
240 	real_net = batadv_getlink_net(netdev, net);
241 
242 	/* iflink to itself, most likely physical device */
243 	if (net == real_net && netdev->ifindex == iflink) {
244 		real_netdev = netdev;
245 		dev_hold(real_netdev);
246 		goto out;
247 	}
248 
249 	real_netdev = dev_get_by_index(real_net, iflink);
250 
251 out:
252 	batadv_hardif_put(hard_iface);
253 	return real_netdev;
254 }
255 
256 /**
257  * batadv_get_real_netdev() - check if the given net_device struct is a virtual
258  *  interface on top of another 'real' interface
259  * @net_device: the device to check
260  *
261  * Return: the 'real' net device or the original net device and NULL in case
262  *  of an error.
263  */
batadv_get_real_netdev(struct net_device * net_device)264 struct net_device *batadv_get_real_netdev(struct net_device *net_device)
265 {
266 	struct net_device *real_netdev;
267 
268 	rtnl_lock();
269 	real_netdev = batadv_get_real_netdevice(net_device);
270 	rtnl_unlock();
271 
272 	return real_netdev;
273 }
274 
275 /**
276  * batadv_is_wext_netdev() - check if the given net_device struct is a
277  *  wext wifi interface
278  * @net_device: the device to check
279  *
280  * Return: true if the net device is a wext wireless device, false
281  *  otherwise.
282  */
batadv_is_wext_netdev(struct net_device * net_device)283 static bool batadv_is_wext_netdev(struct net_device *net_device)
284 {
285 	if (!net_device)
286 		return false;
287 
288 #ifdef CONFIG_WIRELESS_EXT
289 	/* pre-cfg80211 drivers have to implement WEXT, so it is possible to
290 	 * check for wireless_handlers != NULL
291 	 */
292 	if (net_device->wireless_handlers)
293 		return true;
294 #endif
295 
296 	return false;
297 }
298 
299 /**
300  * batadv_is_cfg80211_netdev() - check if the given net_device struct is a
301  *  cfg80211 wifi interface
302  * @net_device: the device to check
303  *
304  * Return: true if the net device is a cfg80211 wireless device, false
305  *  otherwise.
306  */
batadv_is_cfg80211_netdev(struct net_device * net_device)307 static bool batadv_is_cfg80211_netdev(struct net_device *net_device)
308 {
309 	if (!net_device)
310 		return false;
311 
312 #if IS_ENABLED(CONFIG_CFG80211)
313 	/* cfg80211 drivers have to set ieee80211_ptr */
314 	if (net_device->ieee80211_ptr)
315 		return true;
316 #endif
317 
318 	return false;
319 }
320 
321 /**
322  * batadv_wifi_flags_evaluate() - calculate wifi flags for net_device
323  * @net_device: the device to check
324  *
325  * Return: batadv_hard_iface_wifi_flags flags of the device
326  */
batadv_wifi_flags_evaluate(struct net_device * net_device)327 static u32 batadv_wifi_flags_evaluate(struct net_device *net_device)
328 {
329 	u32 wifi_flags = 0;
330 	struct net_device *real_netdev;
331 
332 	if (batadv_is_wext_netdev(net_device))
333 		wifi_flags |= BATADV_HARDIF_WIFI_WEXT_DIRECT;
334 
335 	if (batadv_is_cfg80211_netdev(net_device))
336 		wifi_flags |= BATADV_HARDIF_WIFI_CFG80211_DIRECT;
337 
338 	real_netdev = batadv_get_real_netdevice(net_device);
339 	if (!real_netdev)
340 		return wifi_flags;
341 
342 	if (real_netdev == net_device)
343 		goto out;
344 
345 	if (batadv_is_wext_netdev(real_netdev))
346 		wifi_flags |= BATADV_HARDIF_WIFI_WEXT_INDIRECT;
347 
348 	if (batadv_is_cfg80211_netdev(real_netdev))
349 		wifi_flags |= BATADV_HARDIF_WIFI_CFG80211_INDIRECT;
350 
351 out:
352 	dev_put(real_netdev);
353 	return wifi_flags;
354 }
355 
356 /**
357  * batadv_is_cfg80211_hardif() - check if the given hardif is a cfg80211 wifi
358  *  interface
359  * @hard_iface: the device to check
360  *
361  * Return: true if the net device is a cfg80211 wireless device, false
362  *  otherwise.
363  */
batadv_is_cfg80211_hardif(struct batadv_hard_iface * hard_iface)364 bool batadv_is_cfg80211_hardif(struct batadv_hard_iface *hard_iface)
365 {
366 	u32 allowed_flags = 0;
367 
368 	allowed_flags |= BATADV_HARDIF_WIFI_CFG80211_DIRECT;
369 	allowed_flags |= BATADV_HARDIF_WIFI_CFG80211_INDIRECT;
370 
371 	return !!(hard_iface->wifi_flags & allowed_flags);
372 }
373 
374 /**
375  * batadv_is_wifi_hardif() - check if the given hardif is a wifi interface
376  * @hard_iface: the device to check
377  *
378  * Return: true if the net device is a 802.11 wireless device, false otherwise.
379  */
batadv_is_wifi_hardif(struct batadv_hard_iface * hard_iface)380 bool batadv_is_wifi_hardif(struct batadv_hard_iface *hard_iface)
381 {
382 	if (!hard_iface)
383 		return false;
384 
385 	return hard_iface->wifi_flags != 0;
386 }
387 
388 /**
389  * batadv_hardif_no_broadcast() - check whether (re)broadcast is necessary
390  * @if_outgoing: the outgoing interface checked and considered for (re)broadcast
391  * @orig_addr: the originator of this packet
392  * @orig_neigh: originator address of the forwarder we just got the packet from
393  *  (NULL if we originated)
394  *
395  * Checks whether a packet needs to be (re)broadcasted on the given interface.
396  *
397  * Return:
398  *	BATADV_HARDIF_BCAST_NORECIPIENT: No neighbor on interface
399  *	BATADV_HARDIF_BCAST_DUPFWD: Just one neighbor, but it is the forwarder
400  *	BATADV_HARDIF_BCAST_DUPORIG: Just one neighbor, but it is the originator
401  *	BATADV_HARDIF_BCAST_OK: Several neighbors, must broadcast
402  */
batadv_hardif_no_broadcast(struct batadv_hard_iface * if_outgoing,u8 * orig_addr,u8 * orig_neigh)403 int batadv_hardif_no_broadcast(struct batadv_hard_iface *if_outgoing,
404 			       u8 *orig_addr, u8 *orig_neigh)
405 {
406 	struct batadv_hardif_neigh_node *hardif_neigh;
407 	struct hlist_node *first;
408 	int ret = BATADV_HARDIF_BCAST_OK;
409 
410 	rcu_read_lock();
411 
412 	/* 0 neighbors -> no (re)broadcast */
413 	first = rcu_dereference(hlist_first_rcu(&if_outgoing->neigh_list));
414 	if (!first) {
415 		ret = BATADV_HARDIF_BCAST_NORECIPIENT;
416 		goto out;
417 	}
418 
419 	/* >1 neighbors -> (re)broadcast */
420 	if (rcu_dereference(hlist_next_rcu(first)))
421 		goto out;
422 
423 	hardif_neigh = hlist_entry(first, struct batadv_hardif_neigh_node,
424 				   list);
425 
426 	/* 1 neighbor, is the originator -> no rebroadcast */
427 	if (orig_addr && batadv_compare_eth(hardif_neigh->orig, orig_addr)) {
428 		ret = BATADV_HARDIF_BCAST_DUPORIG;
429 	/* 1 neighbor, is the one we received from -> no rebroadcast */
430 	} else if (orig_neigh &&
431 		   batadv_compare_eth(hardif_neigh->orig, orig_neigh)) {
432 		ret = BATADV_HARDIF_BCAST_DUPFWD;
433 	}
434 
435 out:
436 	rcu_read_unlock();
437 	return ret;
438 }
439 
440 static struct batadv_hard_iface *
batadv_hardif_get_active(const struct net_device * soft_iface)441 batadv_hardif_get_active(const struct net_device *soft_iface)
442 {
443 	struct batadv_hard_iface *hard_iface;
444 
445 	rcu_read_lock();
446 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
447 		if (hard_iface->soft_iface != soft_iface)
448 			continue;
449 
450 		if (hard_iface->if_status == BATADV_IF_ACTIVE &&
451 		    kref_get_unless_zero(&hard_iface->refcount))
452 			goto out;
453 	}
454 
455 	hard_iface = NULL;
456 
457 out:
458 	rcu_read_unlock();
459 	return hard_iface;
460 }
461 
batadv_primary_if_update_addr(struct batadv_priv * bat_priv,struct batadv_hard_iface * oldif)462 static void batadv_primary_if_update_addr(struct batadv_priv *bat_priv,
463 					  struct batadv_hard_iface *oldif)
464 {
465 	struct batadv_hard_iface *primary_if;
466 
467 	primary_if = batadv_primary_if_get_selected(bat_priv);
468 	if (!primary_if)
469 		goto out;
470 
471 	batadv_dat_init_own_addr(bat_priv, primary_if);
472 	batadv_bla_update_orig_address(bat_priv, primary_if, oldif);
473 out:
474 	batadv_hardif_put(primary_if);
475 }
476 
batadv_primary_if_select(struct batadv_priv * bat_priv,struct batadv_hard_iface * new_hard_iface)477 static void batadv_primary_if_select(struct batadv_priv *bat_priv,
478 				     struct batadv_hard_iface *new_hard_iface)
479 {
480 	struct batadv_hard_iface *curr_hard_iface;
481 
482 	ASSERT_RTNL();
483 
484 	if (new_hard_iface)
485 		kref_get(&new_hard_iface->refcount);
486 
487 	curr_hard_iface = rcu_replace_pointer(bat_priv->primary_if,
488 					      new_hard_iface, 1);
489 
490 	if (!new_hard_iface)
491 		goto out;
492 
493 	bat_priv->algo_ops->iface.primary_set(new_hard_iface);
494 	batadv_primary_if_update_addr(bat_priv, curr_hard_iface);
495 
496 out:
497 	batadv_hardif_put(curr_hard_iface);
498 }
499 
500 static bool
batadv_hardif_is_iface_up(const struct batadv_hard_iface * hard_iface)501 batadv_hardif_is_iface_up(const struct batadv_hard_iface *hard_iface)
502 {
503 	if (hard_iface->net_dev->flags & IFF_UP)
504 		return true;
505 
506 	return false;
507 }
508 
batadv_check_known_mac_addr(const struct net_device * net_dev)509 static void batadv_check_known_mac_addr(const struct net_device *net_dev)
510 {
511 	const struct batadv_hard_iface *hard_iface;
512 
513 	rcu_read_lock();
514 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
515 		if (hard_iface->if_status != BATADV_IF_ACTIVE &&
516 		    hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED)
517 			continue;
518 
519 		if (hard_iface->net_dev == net_dev)
520 			continue;
521 
522 		if (!batadv_compare_eth(hard_iface->net_dev->dev_addr,
523 					net_dev->dev_addr))
524 			continue;
525 
526 		pr_warn("The newly added mac address (%pM) already exists on: %s\n",
527 			net_dev->dev_addr, hard_iface->net_dev->name);
528 		pr_warn("It is strongly recommended to keep mac addresses unique to avoid problems!\n");
529 	}
530 	rcu_read_unlock();
531 }
532 
533 /**
534  * batadv_hardif_recalc_extra_skbroom() - Recalculate skbuff extra head/tailroom
535  * @soft_iface: netdev struct of the mesh interface
536  */
batadv_hardif_recalc_extra_skbroom(struct net_device * soft_iface)537 static void batadv_hardif_recalc_extra_skbroom(struct net_device *soft_iface)
538 {
539 	const struct batadv_hard_iface *hard_iface;
540 	unsigned short lower_header_len = ETH_HLEN;
541 	unsigned short lower_headroom = 0;
542 	unsigned short lower_tailroom = 0;
543 	unsigned short needed_headroom;
544 
545 	rcu_read_lock();
546 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
547 		if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
548 			continue;
549 
550 		if (hard_iface->soft_iface != soft_iface)
551 			continue;
552 
553 		lower_header_len = max_t(unsigned short, lower_header_len,
554 					 hard_iface->net_dev->hard_header_len);
555 
556 		lower_headroom = max_t(unsigned short, lower_headroom,
557 				       hard_iface->net_dev->needed_headroom);
558 
559 		lower_tailroom = max_t(unsigned short, lower_tailroom,
560 				       hard_iface->net_dev->needed_tailroom);
561 	}
562 	rcu_read_unlock();
563 
564 	needed_headroom = lower_headroom + (lower_header_len - ETH_HLEN);
565 	needed_headroom += batadv_max_header_len();
566 
567 	/* fragmentation headers don't strip the unicast/... header */
568 	needed_headroom += sizeof(struct batadv_frag_packet);
569 
570 	soft_iface->needed_headroom = needed_headroom;
571 	soft_iface->needed_tailroom = lower_tailroom;
572 }
573 
574 /**
575  * batadv_hardif_min_mtu() - Calculate maximum MTU for soft interface
576  * @soft_iface: netdev struct of the soft interface
577  *
578  * Return: MTU for the soft-interface (limited by the minimal MTU of all active
579  *  slave interfaces)
580  */
batadv_hardif_min_mtu(struct net_device * soft_iface)581 int batadv_hardif_min_mtu(struct net_device *soft_iface)
582 {
583 	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
584 	const struct batadv_hard_iface *hard_iface;
585 	int min_mtu = INT_MAX;
586 
587 	rcu_read_lock();
588 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
589 		if (hard_iface->if_status != BATADV_IF_ACTIVE &&
590 		    hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED)
591 			continue;
592 
593 		if (hard_iface->soft_iface != soft_iface)
594 			continue;
595 
596 		min_mtu = min_t(int, hard_iface->net_dev->mtu, min_mtu);
597 	}
598 	rcu_read_unlock();
599 
600 	if (atomic_read(&bat_priv->fragmentation) == 0)
601 		goto out;
602 
603 	/* with fragmentation enabled the maximum size of internally generated
604 	 * packets such as translation table exchanges or tvlv containers, etc
605 	 * has to be calculated
606 	 */
607 	min_mtu = min_t(int, min_mtu, BATADV_FRAG_MAX_FRAG_SIZE);
608 	min_mtu -= sizeof(struct batadv_frag_packet);
609 	min_mtu *= BATADV_FRAG_MAX_FRAGMENTS;
610 
611 out:
612 	/* report to the other components the maximum amount of bytes that
613 	 * batman-adv can send over the wire (without considering the payload
614 	 * overhead). For example, this value is used by TT to compute the
615 	 * maximum local table size
616 	 */
617 	atomic_set(&bat_priv->packet_size_max, min_mtu);
618 
619 	/* the real soft-interface MTU is computed by removing the payload
620 	 * overhead from the maximum amount of bytes that was just computed.
621 	 *
622 	 * However batman-adv does not support MTUs bigger than ETH_DATA_LEN
623 	 */
624 	return min_t(int, min_mtu - batadv_max_header_len(), ETH_DATA_LEN);
625 }
626 
627 /**
628  * batadv_update_min_mtu() - Adjusts the MTU if a new interface with a smaller
629  *  MTU appeared
630  * @soft_iface: netdev struct of the soft interface
631  */
batadv_update_min_mtu(struct net_device * soft_iface)632 void batadv_update_min_mtu(struct net_device *soft_iface)
633 {
634 	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
635 	int limit_mtu;
636 	int mtu;
637 
638 	mtu = batadv_hardif_min_mtu(soft_iface);
639 
640 	if (bat_priv->mtu_set_by_user)
641 		limit_mtu = bat_priv->mtu_set_by_user;
642 	else
643 		limit_mtu = ETH_DATA_LEN;
644 
645 	mtu = min(mtu, limit_mtu);
646 	dev_set_mtu(soft_iface, mtu);
647 
648 	/* Check if the local translate table should be cleaned up to match a
649 	 * new (and smaller) MTU.
650 	 */
651 	batadv_tt_local_resize_to_mtu(soft_iface);
652 }
653 
654 static void
batadv_hardif_activate_interface(struct batadv_hard_iface * hard_iface)655 batadv_hardif_activate_interface(struct batadv_hard_iface *hard_iface)
656 {
657 	struct batadv_priv *bat_priv;
658 	struct batadv_hard_iface *primary_if = NULL;
659 
660 	if (hard_iface->if_status != BATADV_IF_INACTIVE)
661 		goto out;
662 
663 	bat_priv = netdev_priv(hard_iface->soft_iface);
664 
665 	bat_priv->algo_ops->iface.update_mac(hard_iface);
666 	hard_iface->if_status = BATADV_IF_TO_BE_ACTIVATED;
667 
668 	/* the first active interface becomes our primary interface or
669 	 * the next active interface after the old primary interface was removed
670 	 */
671 	primary_if = batadv_primary_if_get_selected(bat_priv);
672 	if (!primary_if)
673 		batadv_primary_if_select(bat_priv, hard_iface);
674 
675 	batadv_info(hard_iface->soft_iface, "Interface activated: %s\n",
676 		    hard_iface->net_dev->name);
677 
678 	batadv_update_min_mtu(hard_iface->soft_iface);
679 
680 	if (bat_priv->algo_ops->iface.activate)
681 		bat_priv->algo_ops->iface.activate(hard_iface);
682 
683 out:
684 	batadv_hardif_put(primary_if);
685 }
686 
687 static void
batadv_hardif_deactivate_interface(struct batadv_hard_iface * hard_iface)688 batadv_hardif_deactivate_interface(struct batadv_hard_iface *hard_iface)
689 {
690 	if (hard_iface->if_status != BATADV_IF_ACTIVE &&
691 	    hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED)
692 		return;
693 
694 	hard_iface->if_status = BATADV_IF_INACTIVE;
695 
696 	batadv_info(hard_iface->soft_iface, "Interface deactivated: %s\n",
697 		    hard_iface->net_dev->name);
698 
699 	batadv_update_min_mtu(hard_iface->soft_iface);
700 }
701 
702 /**
703  * batadv_hardif_enable_interface() - Enslave hard interface to soft interface
704  * @hard_iface: hard interface to add to soft interface
705  * @soft_iface: netdev struct of the mesh interface
706  *
707  * Return: 0 on success or negative error number in case of failure
708  */
batadv_hardif_enable_interface(struct batadv_hard_iface * hard_iface,struct net_device * soft_iface)709 int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
710 				   struct net_device *soft_iface)
711 {
712 	struct batadv_priv *bat_priv;
713 	__be16 ethertype = htons(ETH_P_BATMAN);
714 	int max_header_len = batadv_max_header_len();
715 	unsigned int required_mtu;
716 	unsigned int hardif_mtu;
717 	int ret;
718 
719 	hardif_mtu = READ_ONCE(hard_iface->net_dev->mtu);
720 	required_mtu = READ_ONCE(soft_iface->mtu) + max_header_len;
721 
722 	if (hardif_mtu < ETH_MIN_MTU + max_header_len)
723 		return -EINVAL;
724 
725 	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
726 		goto out;
727 
728 	kref_get(&hard_iface->refcount);
729 
730 	dev_hold(soft_iface);
731 	hard_iface->soft_iface = soft_iface;
732 	bat_priv = netdev_priv(hard_iface->soft_iface);
733 
734 	ret = netdev_master_upper_dev_link(hard_iface->net_dev,
735 					   soft_iface, NULL, NULL, NULL);
736 	if (ret)
737 		goto err_dev;
738 
739 	ret = bat_priv->algo_ops->iface.enable(hard_iface);
740 	if (ret < 0)
741 		goto err_upper;
742 
743 	hard_iface->if_status = BATADV_IF_INACTIVE;
744 
745 	kref_get(&hard_iface->refcount);
746 	hard_iface->batman_adv_ptype.type = ethertype;
747 	hard_iface->batman_adv_ptype.func = batadv_batman_skb_recv;
748 	hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
749 	dev_add_pack(&hard_iface->batman_adv_ptype);
750 
751 	batadv_info(hard_iface->soft_iface, "Adding interface: %s\n",
752 		    hard_iface->net_dev->name);
753 
754 	if (atomic_read(&bat_priv->fragmentation) &&
755 	    hardif_mtu < required_mtu)
756 		batadv_info(hard_iface->soft_iface,
757 			    "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",
758 			    hard_iface->net_dev->name, hardif_mtu,
759 			    required_mtu);
760 
761 	if (!atomic_read(&bat_priv->fragmentation) &&
762 	    hardif_mtu < required_mtu)
763 		batadv_info(hard_iface->soft_iface,
764 			    "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",
765 			    hard_iface->net_dev->name, hardif_mtu,
766 			    required_mtu);
767 
768 	if (batadv_hardif_is_iface_up(hard_iface))
769 		batadv_hardif_activate_interface(hard_iface);
770 	else
771 		batadv_err(hard_iface->soft_iface,
772 			   "Not using interface %s (retrying later): interface not active\n",
773 			   hard_iface->net_dev->name);
774 
775 	batadv_hardif_recalc_extra_skbroom(soft_iface);
776 
777 	if (bat_priv->algo_ops->iface.enabled)
778 		bat_priv->algo_ops->iface.enabled(hard_iface);
779 
780 out:
781 	return 0;
782 
783 err_upper:
784 	netdev_upper_dev_unlink(hard_iface->net_dev, soft_iface);
785 err_dev:
786 	hard_iface->soft_iface = NULL;
787 	dev_put(soft_iface);
788 	batadv_hardif_put(hard_iface);
789 	return ret;
790 }
791 
792 /**
793  * batadv_hardif_cnt() - get number of interfaces enslaved to soft interface
794  * @soft_iface: soft interface to check
795  *
796  * This function is only using RCU for locking - the result can therefore be
797  * off when another function is modifying the list at the same time. The
798  * caller can use the rtnl_lock to make sure that the count is accurate.
799  *
800  * Return: number of connected/enslaved hard interfaces
801  */
batadv_hardif_cnt(const struct net_device * soft_iface)802 static size_t batadv_hardif_cnt(const struct net_device *soft_iface)
803 {
804 	struct batadv_hard_iface *hard_iface;
805 	size_t count = 0;
806 
807 	rcu_read_lock();
808 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
809 		if (hard_iface->soft_iface != soft_iface)
810 			continue;
811 
812 		count++;
813 	}
814 	rcu_read_unlock();
815 
816 	return count;
817 }
818 
819 /**
820  * batadv_hardif_disable_interface() - Remove hard interface from soft interface
821  * @hard_iface: hard interface to be removed
822  */
batadv_hardif_disable_interface(struct batadv_hard_iface * hard_iface)823 void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface)
824 {
825 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
826 	struct batadv_hard_iface *primary_if = NULL;
827 
828 	batadv_hardif_deactivate_interface(hard_iface);
829 
830 	if (hard_iface->if_status != BATADV_IF_INACTIVE)
831 		goto out;
832 
833 	batadv_info(hard_iface->soft_iface, "Removing interface: %s\n",
834 		    hard_iface->net_dev->name);
835 	dev_remove_pack(&hard_iface->batman_adv_ptype);
836 	batadv_hardif_put(hard_iface);
837 
838 	primary_if = batadv_primary_if_get_selected(bat_priv);
839 	if (hard_iface == primary_if) {
840 		struct batadv_hard_iface *new_if;
841 
842 		new_if = batadv_hardif_get_active(hard_iface->soft_iface);
843 		batadv_primary_if_select(bat_priv, new_if);
844 
845 		batadv_hardif_put(new_if);
846 	}
847 
848 	bat_priv->algo_ops->iface.disable(hard_iface);
849 	hard_iface->if_status = BATADV_IF_NOT_IN_USE;
850 
851 	/* delete all references to this hard_iface */
852 	batadv_purge_orig_ref(bat_priv);
853 	batadv_purge_outstanding_packets(bat_priv, hard_iface);
854 	dev_put(hard_iface->soft_iface);
855 
856 	netdev_upper_dev_unlink(hard_iface->net_dev, hard_iface->soft_iface);
857 	batadv_hardif_recalc_extra_skbroom(hard_iface->soft_iface);
858 
859 	/* nobody uses this interface anymore */
860 	if (batadv_hardif_cnt(hard_iface->soft_iface) <= 1)
861 		batadv_gw_check_client_stop(bat_priv);
862 
863 	hard_iface->soft_iface = NULL;
864 	batadv_hardif_put(hard_iface);
865 
866 out:
867 	batadv_hardif_put(primary_if);
868 }
869 
870 static struct batadv_hard_iface *
batadv_hardif_add_interface(struct net_device * net_dev)871 batadv_hardif_add_interface(struct net_device *net_dev)
872 {
873 	struct batadv_hard_iface *hard_iface;
874 
875 	ASSERT_RTNL();
876 
877 	if (!batadv_is_valid_iface(net_dev))
878 		goto out;
879 
880 	dev_hold(net_dev);
881 
882 	hard_iface = kzalloc(sizeof(*hard_iface), GFP_ATOMIC);
883 	if (!hard_iface)
884 		goto release_dev;
885 
886 	hard_iface->net_dev = net_dev;
887 	hard_iface->soft_iface = NULL;
888 	hard_iface->if_status = BATADV_IF_NOT_IN_USE;
889 
890 	INIT_LIST_HEAD(&hard_iface->list);
891 	INIT_HLIST_HEAD(&hard_iface->neigh_list);
892 
893 	mutex_init(&hard_iface->bat_iv.ogm_buff_mutex);
894 	spin_lock_init(&hard_iface->neigh_list_lock);
895 	kref_init(&hard_iface->refcount);
896 
897 	hard_iface->num_bcasts = BATADV_NUM_BCASTS_DEFAULT;
898 	hard_iface->wifi_flags = batadv_wifi_flags_evaluate(net_dev);
899 	if (batadv_is_wifi_hardif(hard_iface))
900 		hard_iface->num_bcasts = BATADV_NUM_BCASTS_WIRELESS;
901 
902 	atomic_set(&hard_iface->hop_penalty, 0);
903 
904 	batadv_v_hardif_init(hard_iface);
905 
906 	batadv_check_known_mac_addr(hard_iface->net_dev);
907 	kref_get(&hard_iface->refcount);
908 	list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);
909 	batadv_hardif_generation++;
910 
911 	return hard_iface;
912 
913 release_dev:
914 	dev_put(net_dev);
915 out:
916 	return NULL;
917 }
918 
batadv_hardif_remove_interface(struct batadv_hard_iface * hard_iface)919 static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface)
920 {
921 	ASSERT_RTNL();
922 
923 	/* first deactivate interface */
924 	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
925 		batadv_hardif_disable_interface(hard_iface);
926 
927 	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
928 		return;
929 
930 	hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;
931 	batadv_hardif_put(hard_iface);
932 }
933 
934 /**
935  * batadv_hard_if_event_softif() - Handle events for soft interfaces
936  * @event: NETDEV_* event to handle
937  * @net_dev: net_device which generated an event
938  *
939  * Return: NOTIFY_* result
940  */
batadv_hard_if_event_softif(unsigned long event,struct net_device * net_dev)941 static int batadv_hard_if_event_softif(unsigned long event,
942 				       struct net_device *net_dev)
943 {
944 	struct batadv_priv *bat_priv;
945 
946 	switch (event) {
947 	case NETDEV_REGISTER:
948 		bat_priv = netdev_priv(net_dev);
949 		batadv_softif_create_vlan(bat_priv, BATADV_NO_FLAGS);
950 		break;
951 	}
952 
953 	return NOTIFY_DONE;
954 }
955 
batadv_hard_if_event(struct notifier_block * this,unsigned long event,void * ptr)956 static int batadv_hard_if_event(struct notifier_block *this,
957 				unsigned long event, void *ptr)
958 {
959 	struct net_device *net_dev = netdev_notifier_info_to_dev(ptr);
960 	struct batadv_hard_iface *hard_iface;
961 	struct batadv_hard_iface *primary_if = NULL;
962 	struct batadv_priv *bat_priv;
963 
964 	if (batadv_softif_is_valid(net_dev))
965 		return batadv_hard_if_event_softif(event, net_dev);
966 
967 	hard_iface = batadv_hardif_get_by_netdev(net_dev);
968 	if (!hard_iface && (event == NETDEV_REGISTER ||
969 			    event == NETDEV_POST_TYPE_CHANGE))
970 		hard_iface = batadv_hardif_add_interface(net_dev);
971 
972 	if (!hard_iface)
973 		goto out;
974 
975 	switch (event) {
976 	case NETDEV_UP:
977 		batadv_hardif_activate_interface(hard_iface);
978 		break;
979 	case NETDEV_GOING_DOWN:
980 	case NETDEV_DOWN:
981 		batadv_hardif_deactivate_interface(hard_iface);
982 		break;
983 	case NETDEV_UNREGISTER:
984 	case NETDEV_PRE_TYPE_CHANGE:
985 		list_del_rcu(&hard_iface->list);
986 		batadv_hardif_generation++;
987 
988 		batadv_hardif_remove_interface(hard_iface);
989 		break;
990 	case NETDEV_CHANGEMTU:
991 		if (hard_iface->soft_iface)
992 			batadv_update_min_mtu(hard_iface->soft_iface);
993 		break;
994 	case NETDEV_CHANGEADDR:
995 		if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
996 			goto hardif_put;
997 
998 		batadv_check_known_mac_addr(hard_iface->net_dev);
999 
1000 		bat_priv = netdev_priv(hard_iface->soft_iface);
1001 		bat_priv->algo_ops->iface.update_mac(hard_iface);
1002 
1003 		primary_if = batadv_primary_if_get_selected(bat_priv);
1004 		if (!primary_if)
1005 			goto hardif_put;
1006 
1007 		if (hard_iface == primary_if)
1008 			batadv_primary_if_update_addr(bat_priv, NULL);
1009 		break;
1010 	case NETDEV_CHANGEUPPER:
1011 		hard_iface->wifi_flags = batadv_wifi_flags_evaluate(net_dev);
1012 		if (batadv_is_wifi_hardif(hard_iface))
1013 			hard_iface->num_bcasts = BATADV_NUM_BCASTS_WIRELESS;
1014 		break;
1015 	default:
1016 		break;
1017 	}
1018 
1019 hardif_put:
1020 	batadv_hardif_put(hard_iface);
1021 out:
1022 	batadv_hardif_put(primary_if);
1023 	return NOTIFY_DONE;
1024 }
1025 
1026 struct notifier_block batadv_hard_if_notifier = {
1027 	.notifier_call = batadv_hard_if_event,
1028 };
1029