net/batman-adv/hard-interface.c

   1 /*
   2  * Copyright (C) 2007-2012 B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner, Simon Wunderlich
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA
  19  *
  20  */
  21
  22 #include "main.h"
  23 #include "hard-interface.h"
  24 #include "soft-interface.h"
  25 #include "send.h"
  26 #include "translation-table.h"
  27 #include "routing.h"
  28 #include "bat_sysfs.h"
  29 #include "originator.h"
  30 #include "hash.h"
  31
  32 #include <linux/if_arp.h>
  33
  34
  35 static int batman_skb_recv(struct sk_buff *skb,
  36                            struct net_device *dev,
  37                            struct packet_type *ptype,
  38                            struct net_device *orig_dev);
  39
  40 void hardif_free_rcu(struct rcu_head *rcu)
  41 {
  42         struct hard_iface *hard_iface;
  43
  44         hard_iface = container_of(rcu, struct hard_iface, rcu);
  45         dev_put(hard_iface->net_dev);
  46         kfree(hard_iface);
  47 }
  48
  49 struct hard_iface *hardif_get_by_netdev(const struct net_device *net_dev)
  50 {
  51         struct hard_iface *hard_iface;
  52
  53         rcu_read_lock();
  54         list_for_each_entry_rcu(hard_iface, &hardif_list, list) {
  55                 if (hard_iface->net_dev == net_dev &&
  56                     atomic_inc_not_zero(&hard_iface->refcount))
  57                         goto out;
  58         }
  59
  60         hard_iface = NULL;
  61
  62 out:
  63         rcu_read_unlock();
  64         return hard_iface;
  65 }
  66
  67 static int is_valid_iface(const struct net_device *net_dev)
  68 {
  69         if (net_dev->flags & IFF_LOOPBACK)
  70                 return 0;
  71
  72         if (net_dev->type != ARPHRD_ETHER)
  73                 return 0;
  74
  75         if (net_dev->addr_len != ETH_ALEN)
  76                 return 0;
  77
  78         /* no batman over batman */
  79         if (softif_is_valid(net_dev))
  80                 return 0;
  81
  82         /* Device is being bridged */
  83         /* if (net_dev->priv_flags & IFF_BRIDGE_PORT)
  84                 return 0; */
  85
  86         return 1;
  87 }
  88
  89 static struct hard_iface *hardif_get_active(const struct net_device *soft_iface)
  90 {
  91         struct hard_iface *hard_iface;
  92
  93         rcu_read_lock();
  94         list_for_each_entry_rcu(hard_iface, &hardif_list, list) {
  95                 if (hard_iface->soft_iface != soft_iface)
  96                         continue;
  97
  98                 if (hard_iface->if_status == IF_ACTIVE &&
  99                     atomic_inc_not_zero(&hard_iface->refcount))
 100                         goto out;
 101         }
 102
 103         hard_iface = NULL;
 104
 105 out:
 106         rcu_read_unlock();
 107         return hard_iface;
 108 }
 109
 110 static void primary_if_update_addr(struct bat_priv *bat_priv)
 111 {
 112         struct vis_packet *vis_packet;
 113         struct hard_iface *primary_if;
 114
 115         primary_if = primary_if_get_selected(bat_priv);
 116         if (!primary_if)
 117                 goto out;
 118
 119         vis_packet = (struct vis_packet *)
 120                                 bat_priv->my_vis_info->skb_packet->data;
 121         memcpy(vis_packet->vis_orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 122         memcpy(vis_packet->sender_orig,
 123                primary_if->net_dev->dev_addr, ETH_ALEN);
 124
 125 out:
 126         if (primary_if)
 127                 hardif_free_ref(primary_if);
 128 }
 129
 130 static void primary_if_select(struct bat_priv *bat_priv,
 131                               struct hard_iface *new_hard_iface)
 132 {
 133         struct hard_iface *curr_hard_iface;
 134
 135         ASSERT_RTNL();
 136
 137         if (new_hard_iface && !atomic_inc_not_zero(&new_hard_iface->refcount))
 138                 new_hard_iface = NULL;
 139
 140         curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
 141         rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);
 142
 143         if (curr_hard_iface)
 144                 hardif_free_ref(curr_hard_iface);
 145
 146         if (!new_hard_iface)
 147                 return;
 148
 149         bat_priv->bat_algo_ops->bat_ogm_init_primary(new_hard_iface);
 150         primary_if_update_addr(bat_priv);
 151 }
 152
 153 static bool hardif_is_iface_up(const struct hard_iface *hard_iface)
 154 {
 155         if (hard_iface->net_dev->flags & IFF_UP)
 156                 return true;
 157
 158         return false;
 159 }
 160
 161 static void check_known_mac_addr(const struct net_device *net_dev)
 162 {
 163         const struct hard_iface *hard_iface;
 164
 165         rcu_read_lock();
 166         list_for_each_entry_rcu(hard_iface, &hardif_list, list) {
 167                 if ((hard_iface->if_status != IF_ACTIVE) &&
 168                     (hard_iface->if_status != IF_TO_BE_ACTIVATED))
 169                         continue;
 170
 171                 if (hard_iface->net_dev == net_dev)
 172                         continue;
 173
 174                 if (!compare_eth(hard_iface->net_dev->dev_addr,
 175                                  net_dev->dev_addr))
 176                         continue;
 177
 178                 pr_warning("The newly added mac address (%pM) already exists on: %s\n",
 179                            net_dev->dev_addr, hard_iface->net_dev->name);
 180                 pr_warning("It is strongly recommended to keep mac addresses unique to avoid problems!\n");
 181         }
 182         rcu_read_unlock();
 183 }
 184
 185 int hardif_min_mtu(struct net_device *soft_iface)
 186 {
 187         const struct bat_priv *bat_priv = netdev_priv(soft_iface);
 188         const struct hard_iface *hard_iface;
 189         /* allow big frames if all devices are capable to do so
 190          * (have MTU > 1500 + BAT_HEADER_LEN) */
 191         int min_mtu = ETH_DATA_LEN;
 192
 193         if (atomic_read(&bat_priv->fragmentation))
 194                 goto out;
 195
 196         rcu_read_lock();
 197         list_for_each_entry_rcu(hard_iface, &hardif_list, list) {
 198                 if ((hard_iface->if_status != IF_ACTIVE) &&
 199                     (hard_iface->if_status != IF_TO_BE_ACTIVATED))
 200                         continue;
 201
 202                 if (hard_iface->soft_iface != soft_iface)
 203                         continue;
 204
 205                 min_mtu = min_t(int, hard_iface->net_dev->mtu - BAT_HEADER_LEN,
 206                                 min_mtu);
 207         }
 208         rcu_read_unlock();
 209 out:
 210         return min_mtu;
 211 }
 212
 213 /* adjusts the MTU if a new interface with a smaller MTU appeared. */
 214 void update_min_mtu(struct net_device *soft_iface)
 215 {
 216         int min_mtu;
 217
 218         min_mtu = hardif_min_mtu(soft_iface);
 219         if (soft_iface->mtu != min_mtu)
 220                 soft_iface->mtu = min_mtu;
 221 }
 222
 223 static void hardif_activate_interface(struct hard_iface *hard_iface)
 224 {
 225         struct bat_priv *bat_priv;
 226         struct hard_iface *primary_if = NULL;
 227
 228         if (hard_iface->if_status != IF_INACTIVE)
 229                 goto out;
 230
 231         bat_priv = netdev_priv(hard_iface->soft_iface);
 232
 233         bat_priv->bat_algo_ops->bat_ogm_update_mac(hard_iface);
 234         hard_iface->if_status = IF_TO_BE_ACTIVATED;
 235
 236         /**
 237          * the first active interface becomes our primary interface or
 238          * the next active interface after the old primary interface was removed
 239          */
 240         primary_if = primary_if_get_selected(bat_priv);
 241         if (!primary_if)
 242                 primary_if_select(bat_priv, hard_iface);
 243
 244         bat_info(hard_iface->soft_iface, "Interface activated: %s\n",
 245                  hard_iface->net_dev->name);
 246
 247         update_min_mtu(hard_iface->soft_iface);
 248
 249 out:
 250         if (primary_if)
 251                 hardif_free_ref(primary_if);
 252 }
 253
 254 static void hardif_deactivate_interface(struct hard_iface *hard_iface)
 255 {
 256         if ((hard_iface->if_status != IF_ACTIVE) &&
 257             (hard_iface->if_status != IF_TO_BE_ACTIVATED))
 258                 return;
 259
 260         hard_iface->if_status = IF_INACTIVE;
 261
 262         bat_info(hard_iface->soft_iface, "Interface deactivated: %s\n",
 263                  hard_iface->net_dev->name);
 264
 265         update_min_mtu(hard_iface->soft_iface);
 266 }
 267
 268 int hardif_enable_interface(struct hard_iface *hard_iface,
 269                             const char *iface_name)
 270 {
 271         struct bat_priv *bat_priv;
 272         struct net_device *soft_iface;
 273         int ret;
 274
 275         if (hard_iface->if_status != IF_NOT_IN_USE)
 276                 goto out;
 277
 278         if (!atomic_inc_not_zero(&hard_iface->refcount))
 279                 goto out;
 280
 281         /* hard-interface is part of a bridge */
 282         if (hard_iface->net_dev->priv_flags & IFF_BRIDGE_PORT)
 283                 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",
 284                        hard_iface->net_dev->name);
 285
 286         soft_iface = dev_get_by_name(&init_net, iface_name);
 287
 288         if (!soft_iface) {
 289                 soft_iface = softif_create(iface_name);
 290
 291                 if (!soft_iface) {
 292                         ret = -ENOMEM;
 293                         goto err;
 294                 }
 295
 296                 /* dev_get_by_name() increases the reference counter for us */
 297                 dev_hold(soft_iface);
 298         }
 299
 300         if (!softif_is_valid(soft_iface)) {
 301                 pr_err("Can't create batman mesh interface %s: already exists as regular interface\n",
 302                        soft_iface->name);
 303                 dev_put(soft_iface);
 304                 ret = -EINVAL;
 305                 goto err;
 306         }
 307
 308         hard_iface->soft_iface = soft_iface;
 309         bat_priv = netdev_priv(hard_iface->soft_iface);
 310
 311         bat_priv->bat_algo_ops->bat_ogm_init(hard_iface);
 312
 313         if (!hard_iface->packet_buff) {
 314                 bat_err(hard_iface->soft_iface,
 315                         "Can't add interface packet (%s): out of memory\n",
 316                         hard_iface->net_dev->name);
 317                 ret = -ENOMEM;
 318                 goto err;
 319         }
 320
 321         hard_iface->if_num = bat_priv->num_ifaces;
 322         bat_priv->num_ifaces++;
 323         hard_iface->if_status = IF_INACTIVE;
 324         orig_hash_add_if(hard_iface, bat_priv->num_ifaces);
 325
 326         hard_iface->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN);
 327         hard_iface->batman_adv_ptype.func = batman_skb_recv;
 328         hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
 329         dev_add_pack(&hard_iface->batman_adv_ptype);
 330
 331         atomic_set(&hard_iface->seqno, 1);
 332         atomic_set(&hard_iface->frag_seqno, 1);
 333         bat_info(hard_iface->soft_iface, "Adding interface: %s\n",
 334                  hard_iface->net_dev->name);
 335
 336         if (atomic_read(&bat_priv->fragmentation) && hard_iface->net_dev->mtu <
 337                 ETH_DATA_LEN + BAT_HEADER_LEN)
 338                 bat_info(hard_iface->soft_iface,
 339                          "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",
 340                          hard_iface->net_dev->name, hard_iface->net_dev->mtu,
 341                          ETH_DATA_LEN + BAT_HEADER_LEN);
 342
 343         if (!atomic_read(&bat_priv->fragmentation) && hard_iface->net_dev->mtu <
 344                 ETH_DATA_LEN + BAT_HEADER_LEN)
 345                 bat_info(hard_iface->soft_iface,
 346                          "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",
 347                          hard_iface->net_dev->name, hard_iface->net_dev->mtu,
 348                          ETH_DATA_LEN + BAT_HEADER_LEN);
 349
 350         if (hardif_is_iface_up(hard_iface))
 351                 hardif_activate_interface(hard_iface);
 352         else
 353                 bat_err(hard_iface->soft_iface,
 354                         "Not using interface %s (retrying later): interface not active\n",
 355                         hard_iface->net_dev->name);
 356
 357         /* begin scheduling originator messages on that interface */
 358         schedule_bat_ogm(hard_iface);
 359
 360 out:
 361         return 0;
 362
 363 err:
 364         hardif_free_ref(hard_iface);
 365         return ret;
 366 }
 367
 368 void hardif_disable_interface(struct hard_iface *hard_iface)
 369 {
 370         struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 371         struct hard_iface *primary_if = NULL;
 372
 373         if (hard_iface->if_status == IF_ACTIVE)
 374                 hardif_deactivate_interface(hard_iface);
 375
 376         if (hard_iface->if_status != IF_INACTIVE)
 377                 goto out;
 378
 379         bat_info(hard_iface->soft_iface, "Removing interface: %s\n",
 380                  hard_iface->net_dev->name);
 381         dev_remove_pack(&hard_iface->batman_adv_ptype);
 382
 383         bat_priv->num_ifaces--;
 384         orig_hash_del_if(hard_iface, bat_priv->num_ifaces);
 385
 386         primary_if = primary_if_get_selected(bat_priv);
 387         if (hard_iface == primary_if) {
 388                 struct hard_iface *new_if;
 389
 390                 new_if = hardif_get_active(hard_iface->soft_iface);
 391                 primary_if_select(bat_priv, new_if);
 392
 393                 if (new_if)
 394                         hardif_free_ref(new_if);
 395         }
 396
 397         kfree(hard_iface->packet_buff);
 398         hard_iface->packet_buff = NULL;
 399         hard_iface->if_status = IF_NOT_IN_USE;
 400
 401         /* delete all references to this hard_iface */
 402         purge_orig_ref(bat_priv);
 403         purge_outstanding_packets(bat_priv, hard_iface);
 404         dev_put(hard_iface->soft_iface);
 405
 406         /* nobody uses this interface anymore */
 407         if (!bat_priv->num_ifaces)
 408                 softif_destroy(hard_iface->soft_iface);
 409
 410         hard_iface->soft_iface = NULL;
 411         hardif_free_ref(hard_iface);
 412
 413 out:
 414         if (primary_if)
 415                 hardif_free_ref(primary_if);
 416 }
 417
 418 static struct hard_iface *hardif_add_interface(struct net_device *net_dev)
 419 {
 420         struct hard_iface *hard_iface;
 421         int ret;
 422
 423         ASSERT_RTNL();
 424
 425         ret = is_valid_iface(net_dev);
 426         if (ret != 1)
 427                 goto out;
 428
 429         dev_hold(net_dev);
 430
 431         hard_iface = kmalloc(sizeof(*hard_iface), GFP_ATOMIC);
 432         if (!hard_iface)
 433                 goto release_dev;
 434
 435         ret = sysfs_add_hardif(&hard_iface->hardif_obj, net_dev);
 436         if (ret)
 437                 goto free_if;
 438
 439         hard_iface->if_num = -1;
 440         hard_iface->net_dev = net_dev;
 441         hard_iface->soft_iface = NULL;
 442         hard_iface->if_status = IF_NOT_IN_USE;
 443         INIT_LIST_HEAD(&hard_iface->list);
 444         /* extra reference for return */
 445         atomic_set(&hard_iface->refcount, 2);
 446
 447         check_known_mac_addr(hard_iface->net_dev);
 448         list_add_tail_rcu(&hard_iface->list, &hardif_list);
 449
 450         return hard_iface;
 451
 452 free_if:
 453         kfree(hard_iface);
 454 release_dev:
 455         dev_put(net_dev);
 456 out:
 457         return NULL;
 458 }
 459
 460 static void hardif_remove_interface(struct hard_iface *hard_iface)
 461 {
 462         ASSERT_RTNL();
 463
 464         /* first deactivate interface */
 465         if (hard_iface->if_status != IF_NOT_IN_USE)
 466                 hardif_disable_interface(hard_iface);
 467
 468         if (hard_iface->if_status != IF_NOT_IN_USE)
 469                 return;
 470
 471         hard_iface->if_status = IF_TO_BE_REMOVED;
 472         sysfs_del_hardif(&hard_iface->hardif_obj);
 473         hardif_free_ref(hard_iface);
 474 }
 475
 476 void hardif_remove_interfaces(void)
 477 {
 478         struct hard_iface *hard_iface, *hard_iface_tmp;
 479
 480         rtnl_lock();
 481         list_for_each_entry_safe(hard_iface, hard_iface_tmp,
 482                                  &hardif_list, list) {
 483                 list_del_rcu(&hard_iface->list);
 484                 hardif_remove_interface(hard_iface);
 485         }
 486         rtnl_unlock();
 487 }
 488
 489 static int hard_if_event(struct notifier_block *this,
 490                          unsigned long event, void *ptr)
 491 {
 492         struct net_device *net_dev = ptr;
 493         struct hard_iface *hard_iface = hardif_get_by_netdev(net_dev);
 494         struct hard_iface *primary_if = NULL;
 495         struct bat_priv *bat_priv;
 496
 497         if (!hard_iface && event == NETDEV_REGISTER)
 498                 hard_iface = hardif_add_interface(net_dev);
 499
 500         if (!hard_iface)
 501                 goto out;
 502
 503         switch (event) {
 504         case NETDEV_UP:
 505                 hardif_activate_interface(hard_iface);
 506                 break;
 507         case NETDEV_GOING_DOWN:
 508         case NETDEV_DOWN:
 509                 hardif_deactivate_interface(hard_iface);
 510                 break;
 511         case NETDEV_UNREGISTER:
 512                 list_del_rcu(&hard_iface->list);
 513
 514                 hardif_remove_interface(hard_iface);
 515                 break;
 516         case NETDEV_CHANGEMTU:
 517                 if (hard_iface->soft_iface)
 518                         update_min_mtu(hard_iface->soft_iface);
 519                 break;
 520         case NETDEV_CHANGEADDR:
 521                 if (hard_iface->if_status == IF_NOT_IN_USE)
 522                         goto hardif_put;
 523
 524                 check_known_mac_addr(hard_iface->net_dev);
 525
 526                 bat_priv = netdev_priv(hard_iface->soft_iface);
 527                 bat_priv->bat_algo_ops->bat_ogm_update_mac(hard_iface);
 528
 529                 primary_if = primary_if_get_selected(bat_priv);
 530                 if (!primary_if)
 531                         goto hardif_put;
 532
 533                 if (hard_iface == primary_if)
 534                         primary_if_update_addr(bat_priv);
 535                 break;
 536         default:
 537                 break;
 538         }
 539
 540 hardif_put:
 541         hardif_free_ref(hard_iface);
 542 out:
 543         if (primary_if)
 544                 hardif_free_ref(primary_if);
 545         return NOTIFY_DONE;
 546 }
 547
 548 /* incoming packets with the batman ethertype received on any active hard
 549  * interface */
 550 static int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
 551                            struct packet_type *ptype,
 552                            struct net_device *orig_dev)
 553 {
 554         struct bat_priv *bat_priv;
 555         struct batman_ogm_packet *batman_ogm_packet;
 556         struct hard_iface *hard_iface;
 557         int ret;
 558
 559         hard_iface = container_of(ptype, struct hard_iface, batman_adv_ptype);
 560         skb = skb_share_check(skb, GFP_ATOMIC);
 561
 562         /* skb was released by skb_share_check() */
 563         if (!skb)
 564                 goto err_out;
 565
 566         /* packet should hold at least type and version */
 567         if (unlikely(!pskb_may_pull(skb, 2)))
 568                 goto err_free;
 569
 570         /* expect a valid ethernet header here. */
 571         if (unlikely(skb->mac_len != sizeof(struct ethhdr) ||
 572                      !skb_mac_header(skb)))
 573                 goto err_free;
 574
 575         if (!hard_iface->soft_iface)
 576                 goto err_free;
 577
 578         bat_priv = netdev_priv(hard_iface->soft_iface);
 579
 580         if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE)
 581                 goto err_free;
 582
 583         /* discard frames on not active interfaces */
 584         if (hard_iface->if_status != IF_ACTIVE)
 585                 goto err_free;
 586
 587         batman_ogm_packet = (struct batman_ogm_packet *)skb->data;
 588
 589         if (batman_ogm_packet->header.version != COMPAT_VERSION) {
 590                 bat_dbg(DBG_BATMAN, bat_priv,
 591                         "Drop packet: incompatible batman version (%i)\n",
 592                         batman_ogm_packet->header.version);
 593                 goto err_free;
 594         }
 595
 596         /* all receive handlers return whether they received or reused
 597          * the supplied skb. if not, we have to free the skb. */
 598
 599         switch (batman_ogm_packet->header.packet_type) {
 600                 /* batman originator packet */
 601         case BAT_OGM:
 602                 ret = recv_bat_ogm_packet(skb, hard_iface);
 603                 break;
 604
 605                 /* batman icmp packet */
 606         case BAT_ICMP:
 607                 ret = recv_icmp_packet(skb, hard_iface);
 608                 break;
 609
 610                 /* unicast packet */
 611         case BAT_UNICAST:
 612                 ret = recv_unicast_packet(skb, hard_iface);
 613                 break;
 614
 615                 /* fragmented unicast packet */
 616         case BAT_UNICAST_FRAG:
 617                 ret = recv_ucast_frag_packet(skb, hard_iface);
 618                 break;
 619
 620                 /* broadcast packet */
 621         case BAT_BCAST:
 622                 ret = recv_bcast_packet(skb, hard_iface);
 623                 break;
 624
 625                 /* vis packet */
 626         case BAT_VIS:
 627                 ret = recv_vis_packet(skb, hard_iface);
 628                 break;
 629                 /* Translation table query (request or response) */
 630         case BAT_TT_QUERY:
 631                 ret = recv_tt_query(skb, hard_iface);
 632                 break;
 633                 /* Roaming advertisement */
 634         case BAT_ROAM_ADV:
 635                 ret = recv_roam_adv(skb, hard_iface);
 636                 break;
 637         default:
 638                 ret = NET_RX_DROP;
 639         }
 640
 641         if (ret == NET_RX_DROP)
 642                 kfree_skb(skb);
 643
 644         /* return NET_RX_SUCCESS in any case as we
 645          * most probably dropped the packet for
 646          * routing-logical reasons. */
 647
 648         return NET_RX_SUCCESS;
 649
 650 err_free:
 651         kfree_skb(skb);
 652 err_out:
 653         return NET_RX_DROP;
 654 }
 655
 656 /* This function returns true if the interface represented by ifindex is a
 657  * 802.11 wireless device */
 658 bool is_wifi_iface(int ifindex)
 659 {
 660         struct net_device *net_device = NULL;
 661         bool ret = false;
 662
 663         if (ifindex == NULL_IFINDEX)
 664                 goto out;
 665
 666         net_device = dev_get_by_index(&init_net, ifindex);
 667         if (!net_device)
 668                 goto out;
 669
 670 #ifdef CONFIG_WIRELESS_EXT
 671         /* pre-cfg80211 drivers have to implement WEXT, so it is possible to
 672          * check for wireless_handlers != NULL */
 673         if (net_device->wireless_handlers)
 674                 ret = true;
 675         else
 676 #endif
 677                 /* cfg80211 drivers have to set ieee80211_ptr */
 678                 if (net_device->ieee80211_ptr)
 679                         ret = true;
 680 out:
 681         if (net_device)
 682                 dev_put(net_device);
 683         return ret;
 684 }
 685
 686 struct notifier_block hard_if_notifier = {
 687         .notifier_call = hard_if_event,
 688 };