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1 /* Copyright (C) 2007-2012 B.A.T.M.A.N. contributors:
2  *
3  * Marek Lindner, Simon Wunderlich
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of version 2 of the GNU General Public
7  * License as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17  * 02110-1301, USA
18  */
19
20 #include "main.h"
21 #include "distributed-arp-table.h"
22 #include "hard-interface.h"
23 #include "soft-interface.h"
24 #include "send.h"
25 #include "translation-table.h"
26 #include "routing.h"
27 #include "sysfs.h"
28 #include "originator.h"
29 #include "hash.h"
30 #include "bridge_loop_avoidance.h"
31
32 #include <linux/if_arp.h>
33 #include <linux/if_ether.h>
34
35 void batadv_hardif_free_rcu(struct rcu_head *rcu)
36 {
37         struct batadv_hard_iface *hard_iface;
38
39         hard_iface = container_of(rcu, struct batadv_hard_iface, rcu);
40         dev_put(hard_iface->net_dev);
41         kfree(hard_iface);
42 }
43
44 struct batadv_hard_iface *
45 batadv_hardif_get_by_netdev(const struct net_device *net_dev)
46 {
47         struct batadv_hard_iface *hard_iface;
48
49         rcu_read_lock();
50         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
51                 if (hard_iface->net_dev == net_dev &&
52                     atomic_inc_not_zero(&hard_iface->refcount))
53                         goto out;
54         }
55
56         hard_iface = NULL;
57
58 out:
59         rcu_read_unlock();
60         return hard_iface;
61 }
62
63 /**
64  * batadv_is_on_batman_iface - check if a device is a batman iface descendant
65  * @net_dev: the device to check
66  *
67  * If the user creates any virtual device on top of a batman-adv interface, it
68  * is important to prevent this new interface to be used to create a new mesh
69  * network (this behaviour would lead to a batman-over-batman configuration).
70  * This function recursively checks all the fathers of the device passed as
71  * argument looking for a batman-adv soft interface.
72  *
73  * Returns true if the device is descendant of a batman-adv mesh interface (or
74  * if it is a batman-adv interface itself), false otherwise
75  */
76 static bool batadv_is_on_batman_iface(const struct net_device *net_dev)
77 {
78         struct net_device *parent_dev;
79         bool ret;
80
81         /* check if this is a batman-adv mesh interface */
82         if (batadv_softif_is_valid(net_dev))
83                 return true;
84
85         /* no more parents..stop recursion */
86         if (net_dev->iflink == net_dev->ifindex)
87                 return false;
88
89         /* recurse over the parent device */
90         parent_dev = dev_get_by_index(&init_net, net_dev->iflink);
91         /* if we got a NULL parent_dev there is something broken.. */
92         if (WARN(!parent_dev, "Cannot find parent device"))
93                 return false;
94
95         ret = batadv_is_on_batman_iface(parent_dev);
96
97         if (parent_dev)
98                 dev_put(parent_dev);
99         return ret;
100 }
101
102 static int batadv_is_valid_iface(const struct net_device *net_dev)
103 {
104         if (net_dev->flags & IFF_LOOPBACK)
105                 return 0;
106
107         if (net_dev->type != ARPHRD_ETHER)
108                 return 0;
109
110         if (net_dev->addr_len != ETH_ALEN)
111                 return 0;
112
113         /* no batman over batman */
114         if (batadv_is_on_batman_iface(net_dev))
115                 return 0;
116
117         return 1;
118 }
119
120 static struct batadv_hard_iface *
121 batadv_hardif_get_active(const struct net_device *soft_iface)
122 {
123         struct batadv_hard_iface *hard_iface;
124
125         rcu_read_lock();
126         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
127                 if (hard_iface->soft_iface != soft_iface)
128                         continue;
129
130                 if (hard_iface->if_status == BATADV_IF_ACTIVE &&
131                     atomic_inc_not_zero(&hard_iface->refcount))
132                         goto out;
133         }
134
135         hard_iface = NULL;
136
137 out:
138         rcu_read_unlock();
139         return hard_iface;
140 }
141
142 static void batadv_primary_if_update_addr(struct batadv_priv *bat_priv,
143                                           struct batadv_hard_iface *oldif)
144 {
145         struct batadv_vis_packet *vis_packet;
146         struct batadv_hard_iface *primary_if;
147         struct sk_buff *skb;
148
149         primary_if = batadv_primary_if_get_selected(bat_priv);
150         if (!primary_if)
151                 goto out;
152
153         batadv_dat_init_own_addr(bat_priv, primary_if);
154
155         skb = bat_priv->vis.my_info->skb_packet;
156         vis_packet = (struct batadv_vis_packet *)skb->data;
157         memcpy(vis_packet->vis_orig, primary_if->net_dev->dev_addr, ETH_ALEN);
158         memcpy(vis_packet->sender_orig,
159                primary_if->net_dev->dev_addr, ETH_ALEN);
160
161         batadv_bla_update_orig_address(bat_priv, primary_if, oldif);
162 out:
163         if (primary_if)
164                 batadv_hardif_free_ref(primary_if);
165 }
166
167 static void batadv_primary_if_select(struct batadv_priv *bat_priv,
168                                      struct batadv_hard_iface *new_hard_iface)
169 {
170         struct batadv_hard_iface *curr_hard_iface;
171
172         ASSERT_RTNL();
173
174         if (new_hard_iface && !atomic_inc_not_zero(&new_hard_iface->refcount))
175                 new_hard_iface = NULL;
176
177         curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
178         rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);
179
180         if (!new_hard_iface)
181                 goto out;
182
183         bat_priv->bat_algo_ops->bat_primary_iface_set(new_hard_iface);
184         batadv_primary_if_update_addr(bat_priv, curr_hard_iface);
185
186 out:
187         if (curr_hard_iface)
188                 batadv_hardif_free_ref(curr_hard_iface);
189 }
190
191 static bool
192 batadv_hardif_is_iface_up(const struct batadv_hard_iface *hard_iface)
193 {
194         if (hard_iface->net_dev->flags & IFF_UP)
195                 return true;
196
197         return false;
198 }
199
200 static void batadv_check_known_mac_addr(const struct net_device *net_dev)
201 {
202         const struct batadv_hard_iface *hard_iface;
203
204         rcu_read_lock();
205         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
206                 if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
207                     (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
208                         continue;
209
210                 if (hard_iface->net_dev == net_dev)
211                         continue;
212
213                 if (!batadv_compare_eth(hard_iface->net_dev->dev_addr,
214                                         net_dev->dev_addr))
215                         continue;
216
217                 pr_warn("The newly added mac address (%pM) already exists on: %s\n",
218                         net_dev->dev_addr, hard_iface->net_dev->name);
219                 pr_warn("It is strongly recommended to keep mac addresses unique to avoid problems!\n");
220         }
221         rcu_read_unlock();
222 }
223
224 int batadv_hardif_min_mtu(struct net_device *soft_iface)
225 {
226         const struct batadv_priv *bat_priv = netdev_priv(soft_iface);
227         const struct batadv_hard_iface *hard_iface;
228         /* allow big frames if all devices are capable to do so
229          * (have MTU > 1500 + BAT_HEADER_LEN)
230          */
231         int min_mtu = ETH_DATA_LEN;
232
233         if (atomic_read(&bat_priv->fragmentation))
234                 goto out;
235
236         rcu_read_lock();
237         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
238                 if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
239                     (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
240                         continue;
241
242                 if (hard_iface->soft_iface != soft_iface)
243                         continue;
244
245                 min_mtu = min_t(int,
246                                 hard_iface->net_dev->mtu - BATADV_HEADER_LEN,
247                                 min_mtu);
248         }
249         rcu_read_unlock();
250 out:
251         return min_mtu;
252 }
253
254 /* adjusts the MTU if a new interface with a smaller MTU appeared. */
255 void batadv_update_min_mtu(struct net_device *soft_iface)
256 {
257         int min_mtu;
258
259         min_mtu = batadv_hardif_min_mtu(soft_iface);
260         if (soft_iface->mtu != min_mtu)
261                 soft_iface->mtu = min_mtu;
262 }
263
264 static void
265 batadv_hardif_activate_interface(struct batadv_hard_iface *hard_iface)
266 {
267         struct batadv_priv *bat_priv;
268         struct batadv_hard_iface *primary_if = NULL;
269
270         if (hard_iface->if_status != BATADV_IF_INACTIVE)
271                 goto out;
272
273         bat_priv = netdev_priv(hard_iface->soft_iface);
274
275         bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);
276         hard_iface->if_status = BATADV_IF_TO_BE_ACTIVATED;
277
278         /* the first active interface becomes our primary interface or
279          * the next active interface after the old primary interface was removed
280          */
281         primary_if = batadv_primary_if_get_selected(bat_priv);
282         if (!primary_if)
283                 batadv_primary_if_select(bat_priv, hard_iface);
284
285         batadv_info(hard_iface->soft_iface, "Interface activated: %s\n",
286                     hard_iface->net_dev->name);
287
288         batadv_update_min_mtu(hard_iface->soft_iface);
289
290 out:
291         if (primary_if)
292                 batadv_hardif_free_ref(primary_if);
293 }
294
295 static void
296 batadv_hardif_deactivate_interface(struct batadv_hard_iface *hard_iface)
297 {
298         if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
299             (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
300                 return;
301
302         hard_iface->if_status = BATADV_IF_INACTIVE;
303
304         batadv_info(hard_iface->soft_iface, "Interface deactivated: %s\n",
305                     hard_iface->net_dev->name);
306
307         batadv_update_min_mtu(hard_iface->soft_iface);
308 }
309
310 int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
311                                    const char *iface_name)
312 {
313         struct batadv_priv *bat_priv;
314         struct net_device *soft_iface;
315         __be16 ethertype = __constant_htons(ETH_P_BATMAN);
316         int ret;
317
318         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
319                 goto out;
320
321         if (!atomic_inc_not_zero(&hard_iface->refcount))
322                 goto out;
323
324         /* hard-interface is part of a bridge */
325         if (hard_iface->net_dev->priv_flags & IFF_BRIDGE_PORT)
326                 pr_err("You are about to enable batman-adv on '%s' which already is part of a bridge. Unless you know exactly what you are doing this is probably wrong and won't work the way you think it would.\n",
327                        hard_iface->net_dev->name);
328
329         soft_iface = dev_get_by_name(&init_net, iface_name);
330
331         if (!soft_iface) {
332                 soft_iface = batadv_softif_create(iface_name);
333
334                 if (!soft_iface) {
335                         ret = -ENOMEM;
336                         goto err;
337                 }
338
339                 /* dev_get_by_name() increases the reference counter for us */
340                 dev_hold(soft_iface);
341         }
342
343         if (!batadv_softif_is_valid(soft_iface)) {
344                 pr_err("Can't create batman mesh interface %s: already exists as regular interface\n",
345                        soft_iface->name);
346                 ret = -EINVAL;
347                 goto err_dev;
348         }
349
350         hard_iface->soft_iface = soft_iface;
351         bat_priv = netdev_priv(hard_iface->soft_iface);
352
353         ret = bat_priv->bat_algo_ops->bat_iface_enable(hard_iface);
354         if (ret < 0)
355                 goto err_dev;
356
357         hard_iface->if_num = bat_priv->num_ifaces;
358         bat_priv->num_ifaces++;
359         hard_iface->if_status = BATADV_IF_INACTIVE;
360         ret = batadv_orig_hash_add_if(hard_iface, bat_priv->num_ifaces);
361         if (ret < 0) {
362                 bat_priv->bat_algo_ops->bat_iface_disable(hard_iface);
363                 bat_priv->num_ifaces--;
364                 hard_iface->if_status = BATADV_IF_NOT_IN_USE;
365                 goto err_dev;
366         }
367
368         hard_iface->batman_adv_ptype.type = ethertype;
369         hard_iface->batman_adv_ptype.func = batadv_batman_skb_recv;
370         hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
371         dev_add_pack(&hard_iface->batman_adv_ptype);
372
373         atomic_set(&hard_iface->frag_seqno, 1);
374         batadv_info(hard_iface->soft_iface, "Adding interface: %s\n",
375                     hard_iface->net_dev->name);
376
377         if (atomic_read(&bat_priv->fragmentation) &&
378             hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
379                 batadv_info(hard_iface->soft_iface,
380                             "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 %zi would solve the problem.\n",
381                             hard_iface->net_dev->name, hard_iface->net_dev->mtu,
382                             ETH_DATA_LEN + BATADV_HEADER_LEN);
383
384         if (!atomic_read(&bat_priv->fragmentation) &&
385             hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
386                 batadv_info(hard_iface->soft_iface,
387                             "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 %zi.\n",
388                             hard_iface->net_dev->name, hard_iface->net_dev->mtu,
389                             ETH_DATA_LEN + BATADV_HEADER_LEN);
390
391         if (batadv_hardif_is_iface_up(hard_iface))
392                 batadv_hardif_activate_interface(hard_iface);
393         else
394                 batadv_err(hard_iface->soft_iface,
395                            "Not using interface %s (retrying later): interface not active\n",
396                            hard_iface->net_dev->name);
397
398         /* begin scheduling originator messages on that interface */
399         batadv_schedule_bat_ogm(hard_iface);
400
401 out:
402         return 0;
403
404 err_dev:
405         dev_put(soft_iface);
406 err:
407         batadv_hardif_free_ref(hard_iface);
408         return ret;
409 }
410
411 void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface)
412 {
413         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
414         struct batadv_hard_iface *primary_if = NULL;
415
416         if (hard_iface->if_status == BATADV_IF_ACTIVE)
417                 batadv_hardif_deactivate_interface(hard_iface);
418
419         if (hard_iface->if_status != BATADV_IF_INACTIVE)
420                 goto out;
421
422         batadv_info(hard_iface->soft_iface, "Removing interface: %s\n",
423                     hard_iface->net_dev->name);
424         dev_remove_pack(&hard_iface->batman_adv_ptype);
425
426         bat_priv->num_ifaces--;
427         batadv_orig_hash_del_if(hard_iface, bat_priv->num_ifaces);
428
429         primary_if = batadv_primary_if_get_selected(bat_priv);
430         if (hard_iface == primary_if) {
431                 struct batadv_hard_iface *new_if;
432
433                 new_if = batadv_hardif_get_active(hard_iface->soft_iface);
434                 batadv_primary_if_select(bat_priv, new_if);
435
436                 if (new_if)
437                         batadv_hardif_free_ref(new_if);
438         }
439
440         bat_priv->bat_algo_ops->bat_iface_disable(hard_iface);
441         hard_iface->if_status = BATADV_IF_NOT_IN_USE;
442
443         /* delete all references to this hard_iface */
444         batadv_purge_orig_ref(bat_priv);
445         batadv_purge_outstanding_packets(bat_priv, hard_iface);
446         dev_put(hard_iface->soft_iface);
447
448         /* nobody uses this interface anymore */
449         if (!bat_priv->num_ifaces)
450                 batadv_softif_destroy(hard_iface->soft_iface);
451
452         hard_iface->soft_iface = NULL;
453         batadv_hardif_free_ref(hard_iface);
454
455 out:
456         if (primary_if)
457                 batadv_hardif_free_ref(primary_if);
458 }
459
460 static struct batadv_hard_iface *
461 batadv_hardif_add_interface(struct net_device *net_dev)
462 {
463         struct batadv_hard_iface *hard_iface;
464         int ret;
465
466         ASSERT_RTNL();
467
468         ret = batadv_is_valid_iface(net_dev);
469         if (ret != 1)
470                 goto out;
471
472         dev_hold(net_dev);
473
474         hard_iface = kmalloc(sizeof(*hard_iface), GFP_ATOMIC);
475         if (!hard_iface)
476                 goto release_dev;
477
478         ret = batadv_sysfs_add_hardif(&hard_iface->hardif_obj, net_dev);
479         if (ret)
480                 goto free_if;
481
482         hard_iface->if_num = -1;
483         hard_iface->net_dev = net_dev;
484         hard_iface->soft_iface = NULL;
485         hard_iface->if_status = BATADV_IF_NOT_IN_USE;
486         INIT_LIST_HEAD(&hard_iface->list);
487         /* extra reference for return */
488         atomic_set(&hard_iface->refcount, 2);
489
490         batadv_check_known_mac_addr(hard_iface->net_dev);
491         list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);
492
493         /* This can't be called via a bat_priv callback because
494          * we have no bat_priv yet.
495          */
496         atomic_set(&hard_iface->bat_iv.ogm_seqno, 1);
497         hard_iface->bat_iv.ogm_buff = NULL;
498
499         return hard_iface;
500
501 free_if:
502         kfree(hard_iface);
503 release_dev:
504         dev_put(net_dev);
505 out:
506         return NULL;
507 }
508
509 static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface)
510 {
511         ASSERT_RTNL();
512
513         /* first deactivate interface */
514         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
515                 batadv_hardif_disable_interface(hard_iface);
516
517         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
518                 return;
519
520         hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;
521         batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
522         batadv_hardif_free_ref(hard_iface);
523 }
524
525 void batadv_hardif_remove_interfaces(void)
526 {
527         struct batadv_hard_iface *hard_iface, *hard_iface_tmp;
528
529         rtnl_lock();
530         list_for_each_entry_safe(hard_iface, hard_iface_tmp,
531                                  &batadv_hardif_list, list) {
532                 list_del_rcu(&hard_iface->list);
533                 batadv_hardif_remove_interface(hard_iface);
534         }
535         rtnl_unlock();
536 }
537
538 static int batadv_hard_if_event(struct notifier_block *this,
539                                 unsigned long event, void *ptr)
540 {
541         struct net_device *net_dev = ptr;
542         struct batadv_hard_iface *hard_iface;
543         struct batadv_hard_iface *primary_if = NULL;
544         struct batadv_priv *bat_priv;
545
546         hard_iface = batadv_hardif_get_by_netdev(net_dev);
547         if (!hard_iface && event == NETDEV_REGISTER)
548                 hard_iface = batadv_hardif_add_interface(net_dev);
549
550         if (!hard_iface)
551                 goto out;
552
553         switch (event) {
554         case NETDEV_UP:
555                 batadv_hardif_activate_interface(hard_iface);
556                 break;
557         case NETDEV_GOING_DOWN:
558         case NETDEV_DOWN:
559                 batadv_hardif_deactivate_interface(hard_iface);
560                 break;
561         case NETDEV_UNREGISTER:
562                 list_del_rcu(&hard_iface->list);
563
564                 batadv_hardif_remove_interface(hard_iface);
565                 break;
566         case NETDEV_CHANGEMTU:
567                 if (hard_iface->soft_iface)
568                         batadv_update_min_mtu(hard_iface->soft_iface);
569                 break;
570         case NETDEV_CHANGEADDR:
571                 if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
572                         goto hardif_put;
573
574                 batadv_check_known_mac_addr(hard_iface->net_dev);
575
576                 bat_priv = netdev_priv(hard_iface->soft_iface);
577                 bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);
578
579                 primary_if = batadv_primary_if_get_selected(bat_priv);
580                 if (!primary_if)
581                         goto hardif_put;
582
583                 if (hard_iface == primary_if)
584                         batadv_primary_if_update_addr(bat_priv, NULL);
585                 break;
586         default:
587                 break;
588         }
589
590 hardif_put:
591         batadv_hardif_free_ref(hard_iface);
592 out:
593         if (primary_if)
594                 batadv_hardif_free_ref(primary_if);
595         return NOTIFY_DONE;
596 }
597
598 /* This function returns true if the interface represented by ifindex is a
599  * 802.11 wireless device
600  */
601 bool batadv_is_wifi_iface(int ifindex)
602 {
603         struct net_device *net_device = NULL;
604         bool ret = false;
605
606         if (ifindex == BATADV_NULL_IFINDEX)
607                 goto out;
608
609         net_device = dev_get_by_index(&init_net, ifindex);
610         if (!net_device)
611                 goto out;
612
613 #ifdef CONFIG_WIRELESS_EXT
614         /* pre-cfg80211 drivers have to implement WEXT, so it is possible to
615          * check for wireless_handlers != NULL
616          */
617         if (net_device->wireless_handlers)
618                 ret = true;
619         else
620 #endif
621                 /* cfg80211 drivers have to set ieee80211_ptr */
622                 if (net_device->ieee80211_ptr)
623                         ret = true;
624 out:
625         if (net_device)
626                 dev_put(net_device);
627         return ret;
628 }
629
630 struct notifier_block batadv_hard_if_notifier = {
631         .notifier_call = batadv_hard_if_event,
632 };