net/batman-adv/hard-interface.c

   1 /*
   2  * Copyright (C) 2007-2011 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         struct batman_packet *batman_packet;
 135
 136         ASSERT_RTNL();
 137
 138         if (new_hard_iface && !atomic_inc_not_zero(&new_hard_iface->refcount))
 139                 new_hard_iface = NULL;
 140
 141         curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
 142         rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);
 143
 144         if (curr_hard_iface)
 145                 hardif_free_ref(curr_hard_iface);
 146
 147         if (!new_hard_iface)
 148                 return;
 149
 150         batman_packet = (struct batman_packet *)(new_hard_iface->packet_buff);
 151         batman_packet->flags = PRIMARIES_FIRST_HOP;
 152         batman_packet->ttl = TTL;
 153
 154         primary_if_update_addr(bat_priv);
 155 }
 156
 157 static bool hardif_is_iface_up(const struct hard_iface *hard_iface)
 158 {
 159         if (hard_iface->net_dev->flags & IFF_UP)
 160                 return true;
 161
 162         return false;
 163 }
 164
 165 static void update_mac_addresses(struct hard_iface *hard_iface)
 166 {
 167         memcpy(((struct batman_packet *)(hard_iface->packet_buff))->orig,
 168                hard_iface->net_dev->dev_addr, ETH_ALEN);
 169         memcpy(((struct batman_packet *)(hard_iface->packet_buff))->prev_sender,
 170                hard_iface->net_dev->dev_addr, ETH_ALEN);
 171 }
 172
 173 static void check_known_mac_addr(const struct net_device *net_dev)
 174 {
 175         const struct hard_iface *hard_iface;
 176
 177         rcu_read_lock();
 178         list_for_each_entry_rcu(hard_iface, &hardif_list, list) {
 179                 if ((hard_iface->if_status != IF_ACTIVE) &&
 180                     (hard_iface->if_status != IF_TO_BE_ACTIVATED))
 181                         continue;
 182
 183                 if (hard_iface->net_dev == net_dev)
 184                         continue;
 185
 186                 if (!compare_eth(hard_iface->net_dev->dev_addr,
 187                                  net_dev->dev_addr))
 188                         continue;
 189
 190                 pr_warning("The newly added mac address (%pM) already exists "
 191                            "on: %s\n", net_dev->dev_addr,
 192                            hard_iface->net_dev->name);
 193                 pr_warning("It is strongly recommended to keep mac addresses "
 194                            "unique to avoid problems!\n");
 195         }
 196         rcu_read_unlock();
 197 }
 198
 199 int hardif_min_mtu(struct net_device *soft_iface)
 200 {
 201         const struct bat_priv *bat_priv = netdev_priv(soft_iface);
 202         const struct hard_iface *hard_iface;
 203         /* allow big frames if all devices are capable to do so
 204          * (have MTU > 1500 + BAT_HEADER_LEN) */
 205         int min_mtu = ETH_DATA_LEN;
 206
 207         if (atomic_read(&bat_priv->fragmentation))
 208                 goto out;
 209
 210         rcu_read_lock();
 211         list_for_each_entry_rcu(hard_iface, &hardif_list, list) {
 212                 if ((hard_iface->if_status != IF_ACTIVE) &&
 213                     (hard_iface->if_status != IF_TO_BE_ACTIVATED))
 214                         continue;
 215
 216                 if (hard_iface->soft_iface != soft_iface)
 217                         continue;
 218
 219                 min_mtu = min_t(int, hard_iface->net_dev->mtu - BAT_HEADER_LEN,
 220                                 min_mtu);
 221         }
 222         rcu_read_unlock();
 223 out:
 224         return min_mtu;
 225 }
 226
 227 /* adjusts the MTU if a new interface with a smaller MTU appeared. */
 228 void update_min_mtu(struct net_device *soft_iface)
 229 {
 230         int min_mtu;
 231
 232         min_mtu = hardif_min_mtu(soft_iface);
 233         if (soft_iface->mtu != min_mtu)
 234                 soft_iface->mtu = min_mtu;
 235 }
 236
 237 static void hardif_activate_interface(struct hard_iface *hard_iface)
 238 {
 239         struct bat_priv *bat_priv;
 240         struct hard_iface *primary_if = NULL;
 241
 242         if (hard_iface->if_status != IF_INACTIVE)
 243                 goto out;
 244
 245         bat_priv = netdev_priv(hard_iface->soft_iface);
 246
 247         update_mac_addresses(hard_iface);
 248         hard_iface->if_status = IF_TO_BE_ACTIVATED;
 249
 250         /**
 251          * the first active interface becomes our primary interface or
 252          * the next active interface after the old primay interface was removed
 253          */
 254         primary_if = primary_if_get_selected(bat_priv);
 255         if (!primary_if)
 256                 primary_if_select(bat_priv, hard_iface);
 257
 258         bat_info(hard_iface->soft_iface, "Interface activated: %s\n",
 259                  hard_iface->net_dev->name);
 260
 261         update_min_mtu(hard_iface->soft_iface);
 262
 263 out:
 264         if (primary_if)
 265                 hardif_free_ref(primary_if);
 266 }
 267
 268 static void hardif_deactivate_interface(struct hard_iface *hard_iface)
 269 {
 270         if ((hard_iface->if_status != IF_ACTIVE) &&
 271             (hard_iface->if_status != IF_TO_BE_ACTIVATED))
 272                 return;
 273
 274         hard_iface->if_status = IF_INACTIVE;
 275
 276         bat_info(hard_iface->soft_iface, "Interface deactivated: %s\n",
 277                  hard_iface->net_dev->name);
 278
 279         update_min_mtu(hard_iface->soft_iface);
 280 }
 281
 282 int hardif_enable_interface(struct hard_iface *hard_iface,
 283                             const char *iface_name)
 284 {
 285         struct bat_priv *bat_priv;
 286         struct batman_packet *batman_packet;
 287         struct net_device *soft_iface;
 288         int ret;
 289
 290         if (hard_iface->if_status != IF_NOT_IN_USE)
 291                 goto out;
 292
 293         if (!atomic_inc_not_zero(&hard_iface->refcount))
 294                 goto out;
 295
 296         soft_iface = dev_get_by_name(&init_net, iface_name);
 297
 298         if (!soft_iface) {
 299                 soft_iface = softif_create(iface_name);
 300
 301                 if (!soft_iface) {
 302                         ret = -ENOMEM;
 303                         goto err;
 304                 }
 305
 306                 /* dev_get_by_name() increases the reference counter for us */
 307                 dev_hold(soft_iface);
 308         }
 309
 310         if (!softif_is_valid(soft_iface)) {
 311                 pr_err("Can't create batman mesh interface %s: "
 312                        "already exists as regular interface\n",
 313                        soft_iface->name);
 314                 dev_put(soft_iface);
 315                 ret = -EINVAL;
 316                 goto err;
 317         }
 318
 319         hard_iface->soft_iface = soft_iface;
 320         bat_priv = netdev_priv(hard_iface->soft_iface);
 321         hard_iface->packet_len = BAT_PACKET_LEN;
 322         hard_iface->packet_buff = kmalloc(hard_iface->packet_len, GFP_ATOMIC);
 323
 324         if (!hard_iface->packet_buff) {
 325                 bat_err(hard_iface->soft_iface, "Can't add interface packet "
 326                         "(%s): out of memory\n", hard_iface->net_dev->name);
 327                 ret = -ENOMEM;
 328                 goto err;
 329         }
 330
 331         batman_packet = (struct batman_packet *)(hard_iface->packet_buff);
 332         batman_packet->packet_type = BAT_PACKET;
 333         batman_packet->version = COMPAT_VERSION;
 334         batman_packet->flags = NO_FLAGS;
 335         batman_packet->ttl = 2;
 336         batman_packet->tq = TQ_MAX_VALUE;
 337         batman_packet->tt_num_changes = 0;
 338         batman_packet->ttvn = 0;
 339
 340         hard_iface->if_num = bat_priv->num_ifaces;
 341         bat_priv->num_ifaces++;
 342         hard_iface->if_status = IF_INACTIVE;
 343         orig_hash_add_if(hard_iface, bat_priv->num_ifaces);
 344
 345         hard_iface->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN);
 346         hard_iface->batman_adv_ptype.func = batman_skb_recv;
 347         hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
 348         dev_add_pack(&hard_iface->batman_adv_ptype);
 349
 350         atomic_set(&hard_iface->seqno, 1);
 351         atomic_set(&hard_iface->frag_seqno, 1);
 352         bat_info(hard_iface->soft_iface, "Adding interface: %s\n",
 353                  hard_iface->net_dev->name);
 354
 355         if (atomic_read(&bat_priv->fragmentation) && hard_iface->net_dev->mtu <
 356                 ETH_DATA_LEN + BAT_HEADER_LEN)
 357                 bat_info(hard_iface->soft_iface,
 358                         "The MTU of interface %s is too small (%i) to handle "
 359                         "the transport of batman-adv packets. Packets going "
 360                         "over this interface will be fragmented on layer2 "
 361                         "which could impact the performance. Setting the MTU "
 362                         "to %zi would solve the problem.\n",
 363                         hard_iface->net_dev->name, hard_iface->net_dev->mtu,
 364                         ETH_DATA_LEN + BAT_HEADER_LEN);
 365
 366         if (!atomic_read(&bat_priv->fragmentation) && hard_iface->net_dev->mtu <
 367                 ETH_DATA_LEN + BAT_HEADER_LEN)
 368                 bat_info(hard_iface->soft_iface,
 369                         "The MTU of interface %s is too small (%i) to handle "
 370                         "the transport of batman-adv packets. If you experience"
 371                         " problems getting traffic through try increasing the "
 372                         "MTU to %zi.\n",
 373                         hard_iface->net_dev->name, hard_iface->net_dev->mtu,
 374                         ETH_DATA_LEN + BAT_HEADER_LEN);
 375
 376         if (hardif_is_iface_up(hard_iface))
 377                 hardif_activate_interface(hard_iface);
 378         else
 379                 bat_err(hard_iface->soft_iface, "Not using interface %s "
 380                         "(retrying later): interface not active\n",
 381                         hard_iface->net_dev->name);
 382
 383         /* begin scheduling originator messages on that interface */
 384         schedule_own_packet(hard_iface);
 385
 386 out:
 387         return 0;
 388
 389 err:
 390         hardif_free_ref(hard_iface);
 391         return ret;
 392 }
 393
 394 void hardif_disable_interface(struct hard_iface *hard_iface)
 395 {
 396         struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 397         struct hard_iface *primary_if = NULL;
 398
 399         if (hard_iface->if_status == IF_ACTIVE)
 400                 hardif_deactivate_interface(hard_iface);
 401
 402         if (hard_iface->if_status != IF_INACTIVE)
 403                 goto out;
 404
 405         bat_info(hard_iface->soft_iface, "Removing interface: %s\n",
 406                  hard_iface->net_dev->name);
 407         dev_remove_pack(&hard_iface->batman_adv_ptype);
 408
 409         bat_priv->num_ifaces--;
 410         orig_hash_del_if(hard_iface, bat_priv->num_ifaces);
 411
 412         primary_if = primary_if_get_selected(bat_priv);
 413         if (hard_iface == primary_if) {
 414                 struct hard_iface *new_if;
 415
 416                 new_if = hardif_get_active(hard_iface->soft_iface);
 417                 primary_if_select(bat_priv, new_if);
 418
 419                 if (new_if)
 420                         hardif_free_ref(new_if);
 421         }
 422
 423         kfree(hard_iface->packet_buff);
 424         hard_iface->packet_buff = NULL;
 425         hard_iface->if_status = IF_NOT_IN_USE;
 426
 427         /* delete all references to this hard_iface */
 428         purge_orig_ref(bat_priv);
 429         purge_outstanding_packets(bat_priv, hard_iface);
 430         dev_put(hard_iface->soft_iface);
 431
 432         /* nobody uses this interface anymore */
 433         if (!bat_priv->num_ifaces)
 434                 softif_destroy(hard_iface->soft_iface);
 435
 436         hard_iface->soft_iface = NULL;
 437         hardif_free_ref(hard_iface);
 438
 439 out:
 440         if (primary_if)
 441                 hardif_free_ref(primary_if);
 442 }
 443
 444 static struct hard_iface *hardif_add_interface(struct net_device *net_dev)
 445 {
 446         struct hard_iface *hard_iface;
 447         int ret;
 448
 449         ASSERT_RTNL();
 450
 451         ret = is_valid_iface(net_dev);
 452         if (ret != 1)
 453                 goto out;
 454
 455         dev_hold(net_dev);
 456
 457         hard_iface = kmalloc(sizeof(*hard_iface), GFP_ATOMIC);
 458         if (!hard_iface) {
 459                 pr_err("Can't add interface (%s): out of memory\n",
 460                        net_dev->name);
 461                 goto release_dev;
 462         }
 463
 464         ret = sysfs_add_hardif(&hard_iface->hardif_obj, net_dev);
 465         if (ret)
 466                 goto free_if;
 467
 468         hard_iface->if_num = -1;
 469         hard_iface->net_dev = net_dev;
 470         hard_iface->soft_iface = NULL;
 471         hard_iface->if_status = IF_NOT_IN_USE;
 472         INIT_LIST_HEAD(&hard_iface->list);
 473         /* extra reference for return */
 474         atomic_set(&hard_iface->refcount, 2);
 475
 476         check_known_mac_addr(hard_iface->net_dev);
 477         list_add_tail_rcu(&hard_iface->list, &hardif_list);
 478
 479         return hard_iface;
 480
 481 free_if:
 482         kfree(hard_iface);
 483 release_dev:
 484         dev_put(net_dev);
 485 out:
 486         return NULL;
 487 }
 488
 489 static void hardif_remove_interface(struct hard_iface *hard_iface)
 490 {
 491         ASSERT_RTNL();
 492
 493         /* first deactivate interface */
 494         if (hard_iface->if_status != IF_NOT_IN_USE)
 495                 hardif_disable_interface(hard_iface);
 496
 497         if (hard_iface->if_status != IF_NOT_IN_USE)
 498                 return;
 499
 500         hard_iface->if_status = IF_TO_BE_REMOVED;
 501         sysfs_del_hardif(&hard_iface->hardif_obj);
 502         hardif_free_ref(hard_iface);
 503 }
 504
 505 void hardif_remove_interfaces(void)
 506 {
 507         struct hard_iface *hard_iface, *hard_iface_tmp;
 508
 509         rtnl_lock();
 510         list_for_each_entry_safe(hard_iface, hard_iface_tmp,
 511                                  &hardif_list, list) {
 512                 list_del_rcu(&hard_iface->list);
 513                 hardif_remove_interface(hard_iface);
 514         }
 515         rtnl_unlock();
 516 }
 517
 518 static int hard_if_event(struct notifier_block *this,
 519                          unsigned long event, void *ptr)
 520 {
 521         struct net_device *net_dev = ptr;
 522         struct hard_iface *hard_iface = hardif_get_by_netdev(net_dev);
 523         struct hard_iface *primary_if = NULL;
 524         struct bat_priv *bat_priv;
 525
 526         if (!hard_iface && event == NETDEV_REGISTER)
 527                 hard_iface = hardif_add_interface(net_dev);
 528
 529         if (!hard_iface)
 530                 goto out;
 531
 532         switch (event) {
 533         case NETDEV_UP:
 534                 hardif_activate_interface(hard_iface);
 535                 break;
 536         case NETDEV_GOING_DOWN:
 537         case NETDEV_DOWN:
 538                 hardif_deactivate_interface(hard_iface);
 539                 break;
 540         case NETDEV_UNREGISTER:
 541                 list_del_rcu(&hard_iface->list);
 542
 543                 hardif_remove_interface(hard_iface);
 544                 break;
 545         case NETDEV_CHANGEMTU:
 546                 if (hard_iface->soft_iface)
 547                         update_min_mtu(hard_iface->soft_iface);
 548                 break;
 549         case NETDEV_CHANGEADDR:
 550                 if (hard_iface->if_status == IF_NOT_IN_USE)
 551                         goto hardif_put;
 552
 553                 check_known_mac_addr(hard_iface->net_dev);
 554                 update_mac_addresses(hard_iface);
 555
 556                 bat_priv = netdev_priv(hard_iface->soft_iface);
 557                 primary_if = primary_if_get_selected(bat_priv);
 558                 if (!primary_if)
 559                         goto hardif_put;
 560
 561                 if (hard_iface == primary_if)
 562                         primary_if_update_addr(bat_priv);
 563                 break;
 564         default:
 565                 break;
 566         }
 567
 568 hardif_put:
 569         hardif_free_ref(hard_iface);
 570 out:
 571         if (primary_if)
 572                 hardif_free_ref(primary_if);
 573         return NOTIFY_DONE;
 574 }
 575
 576 /* receive a packet with the batman ethertype coming on a hard
 577  * interface */
 578 static int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
 579                            struct packet_type *ptype,
 580                            struct net_device *orig_dev)
 581 {
 582         struct bat_priv *bat_priv;
 583         struct batman_packet *batman_packet;
 584         struct hard_iface *hard_iface;
 585         int ret;
 586
 587         hard_iface = container_of(ptype, struct hard_iface, batman_adv_ptype);
 588         skb = skb_share_check(skb, GFP_ATOMIC);
 589
 590         /* skb was released by skb_share_check() */
 591         if (!skb)
 592                 goto err_out;
 593
 594         /* packet should hold at least type and version */
 595         if (unlikely(!pskb_may_pull(skb, 2)))
 596                 goto err_free;
 597
 598         /* expect a valid ethernet header here. */
 599         if (unlikely(skb->mac_len != sizeof(struct ethhdr)
 600                                 || !skb_mac_header(skb)))
 601                 goto err_free;
 602
 603         if (!hard_iface->soft_iface)
 604                 goto err_free;
 605
 606         bat_priv = netdev_priv(hard_iface->soft_iface);
 607
 608         if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE)
 609                 goto err_free;
 610
 611         /* discard frames on not active interfaces */
 612         if (hard_iface->if_status != IF_ACTIVE)
 613                 goto err_free;
 614
 615         batman_packet = (struct batman_packet *)skb->data;
 616
 617         if (batman_packet->version != COMPAT_VERSION) {
 618                 bat_dbg(DBG_BATMAN, bat_priv,
 619                         "Drop packet: incompatible batman version (%i)\n",
 620                         batman_packet->version);
 621                 goto err_free;
 622         }
 623
 624         /* all receive handlers return whether they received or reused
 625          * the supplied skb. if not, we have to free the skb. */
 626
 627         switch (batman_packet->packet_type) {
 628                 /* batman originator packet */
 629         case BAT_PACKET:
 630                 ret = recv_bat_packet(skb, hard_iface);
 631                 break;
 632
 633                 /* batman icmp packet */
 634         case BAT_ICMP:
 635                 ret = recv_icmp_packet(skb, hard_iface);
 636                 break;
 637
 638                 /* unicast packet */
 639         case BAT_UNICAST:
 640                 ret = recv_unicast_packet(skb, hard_iface);
 641                 break;
 642
 643                 /* fragmented unicast packet */
 644         case BAT_UNICAST_FRAG:
 645                 ret = recv_ucast_frag_packet(skb, hard_iface);
 646                 break;
 647
 648                 /* broadcast packet */
 649         case BAT_BCAST:
 650                 ret = recv_bcast_packet(skb, hard_iface);
 651                 break;
 652
 653                 /* vis packet */
 654         case BAT_VIS:
 655                 ret = recv_vis_packet(skb, hard_iface);
 656                 break;
 657                 /* Translation table query (request or response) */
 658         case BAT_TT_QUERY:
 659                 ret = recv_tt_query(skb, hard_iface);
 660                 break;
 661                 /* Roaming advertisement */
 662         case BAT_ROAM_ADV:
 663                 ret = recv_roam_adv(skb, hard_iface);
 664                 break;
 665         default:
 666                 ret = NET_RX_DROP;
 667         }
 668
 669         if (ret == NET_RX_DROP)
 670                 kfree_skb(skb);
 671
 672         /* return NET_RX_SUCCESS in any case as we
 673          * most probably dropped the packet for
 674          * routing-logical reasons. */
 675
 676         return NET_RX_SUCCESS;
 677
 678 err_free:
 679         kfree_skb(skb);
 680 err_out:
 681         return NET_RX_DROP;
 682 }
 683
 684 struct notifier_block hard_if_notifier = {
 685         .notifier_call = hard_if_event,
 686 };