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