net/batman-adv/hard-interface.c

   1 /* Copyright (C) 2007-2013 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 /**
 461  * batadv_hardif_remove_interface_finish - cleans up the remains of a hardif
 462  * @work: work queue item
 463  *
 464  * Free the parts of the hard interface which can not be removed under
 465  * rtnl lock (to prevent deadlock situations).
 466  */
 467 static void batadv_hardif_remove_interface_finish(struct work_struct *work)
 468 {
 469         struct batadv_hard_iface *hard_iface;
 470
 471         hard_iface = container_of(work, struct batadv_hard_iface,
 472                                   cleanup_work);
 473
 474         batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
 475         batadv_hardif_free_ref(hard_iface);
 476 }
 477
 478 static struct batadv_hard_iface *
 479 batadv_hardif_add_interface(struct net_device *net_dev)
 480 {
 481         struct batadv_hard_iface *hard_iface;
 482         int ret;
 483
 484         ASSERT_RTNL();
 485
 486         ret = batadv_is_valid_iface(net_dev);
 487         if (ret != 1)
 488                 goto out;
 489
 490         dev_hold(net_dev);
 491
 492         hard_iface = kmalloc(sizeof(*hard_iface), GFP_ATOMIC);
 493         if (!hard_iface)
 494                 goto release_dev;
 495
 496         ret = batadv_sysfs_add_hardif(&hard_iface->hardif_obj, net_dev);
 497         if (ret)
 498                 goto free_if;
 499
 500         hard_iface->if_num = -1;
 501         hard_iface->net_dev = net_dev;
 502         hard_iface->soft_iface = NULL;
 503         hard_iface->if_status = BATADV_IF_NOT_IN_USE;
 504         INIT_LIST_HEAD(&hard_iface->list);
 505         INIT_WORK(&hard_iface->cleanup_work,
 506                   batadv_hardif_remove_interface_finish);
 507
 508         /* extra reference for return */
 509         atomic_set(&hard_iface->refcount, 2);
 510
 511         batadv_check_known_mac_addr(hard_iface->net_dev);
 512         list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);
 513
 514         /* This can't be called via a bat_priv callback because
 515          * we have no bat_priv yet.
 516          */
 517         atomic_set(&hard_iface->bat_iv.ogm_seqno, 1);
 518         hard_iface->bat_iv.ogm_buff = NULL;
 519
 520         return hard_iface;
 521
 522 free_if:
 523         kfree(hard_iface);
 524 release_dev:
 525         dev_put(net_dev);
 526 out:
 527         return NULL;
 528 }
 529
 530 static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface)
 531 {
 532         ASSERT_RTNL();
 533
 534         /* first deactivate interface */
 535         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 536                 batadv_hardif_disable_interface(hard_iface);
 537
 538         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 539                 return;
 540
 541         hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;
 542         queue_work(batadv_event_workqueue, &hard_iface->cleanup_work);
 543 }
 544
 545 void batadv_hardif_remove_interfaces(void)
 546 {
 547         struct batadv_hard_iface *hard_iface, *hard_iface_tmp;
 548
 549         rtnl_lock();
 550         list_for_each_entry_safe(hard_iface, hard_iface_tmp,
 551                                  &batadv_hardif_list, list) {
 552                 list_del_rcu(&hard_iface->list);
 553                 batadv_hardif_remove_interface(hard_iface);
 554         }
 555         rtnl_unlock();
 556 }
 557
 558 static int batadv_hard_if_event(struct notifier_block *this,
 559                                 unsigned long event, void *ptr)
 560 {
 561         struct net_device *net_dev = ptr;
 562         struct batadv_hard_iface *hard_iface;
 563         struct batadv_hard_iface *primary_if = NULL;
 564         struct batadv_priv *bat_priv;
 565
 566         hard_iface = batadv_hardif_get_by_netdev(net_dev);
 567         if (!hard_iface && event == NETDEV_REGISTER)
 568                 hard_iface = batadv_hardif_add_interface(net_dev);
 569
 570         if (!hard_iface)
 571                 goto out;
 572
 573         switch (event) {
 574         case NETDEV_UP:
 575                 batadv_hardif_activate_interface(hard_iface);
 576                 break;
 577         case NETDEV_GOING_DOWN:
 578         case NETDEV_DOWN:
 579                 batadv_hardif_deactivate_interface(hard_iface);
 580                 break;
 581         case NETDEV_UNREGISTER:
 582                 list_del_rcu(&hard_iface->list);
 583
 584                 batadv_hardif_remove_interface(hard_iface);
 585                 break;
 586         case NETDEV_CHANGEMTU:
 587                 if (hard_iface->soft_iface)
 588                         batadv_update_min_mtu(hard_iface->soft_iface);
 589                 break;
 590         case NETDEV_CHANGEADDR:
 591                 if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
 592                         goto hardif_put;
 593
 594                 batadv_check_known_mac_addr(hard_iface->net_dev);
 595
 596                 bat_priv = netdev_priv(hard_iface->soft_iface);
 597                 bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);
 598
 599                 primary_if = batadv_primary_if_get_selected(bat_priv);
 600                 if (!primary_if)
 601                         goto hardif_put;
 602
 603                 if (hard_iface == primary_if)
 604                         batadv_primary_if_update_addr(bat_priv, NULL);
 605                 break;
 606         default:
 607                 break;
 608         }
 609
 610 hardif_put:
 611         batadv_hardif_free_ref(hard_iface);
 612 out:
 613         if (primary_if)
 614                 batadv_hardif_free_ref(primary_if);
 615         return NOTIFY_DONE;
 616 }
 617
 618 /* This function returns true if the interface represented by ifindex is a
 619  * 802.11 wireless device
 620  */
 621 bool batadv_is_wifi_iface(int ifindex)
 622 {
 623         struct net_device *net_device = NULL;
 624         bool ret = false;
 625
 626         if (ifindex == BATADV_NULL_IFINDEX)
 627                 goto out;
 628
 629         net_device = dev_get_by_index(&init_net, ifindex);
 630         if (!net_device)
 631                 goto out;
 632
 633 #ifdef CONFIG_WIRELESS_EXT
 634         /* pre-cfg80211 drivers have to implement WEXT, so it is possible to
 635          * check for wireless_handlers != NULL
 636          */
 637         if (net_device->wireless_handlers)
 638                 ret = true;
 639         else
 640 #endif
 641                 /* cfg80211 drivers have to set ieee80211_ptr */
 642                 if (net_device->ieee80211_ptr)
 643                         ret = true;
 644 out:
 645         if (net_device)
 646                 dev_put(net_device);
 647         return ret;
 648 }
 649
 650 struct notifier_block batadv_hard_if_notifier = {
 651         .notifier_call = batadv_hard_if_event,
 652 };