net/batman-adv/originator.c

   1 /* Copyright (C) 2009-2013 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 "originator.h"
  23 #include "hash.h"
  24 #include "translation-table.h"
  25 #include "routing.h"
  26 #include "gateway_client.h"
  27 #include "hard-interface.h"
  28 #include "soft-interface.h"
  29 #include "bridge_loop_avoidance.h"
  30 #include "network-coding.h"
  31 #include "fragmentation.h"
  32
  33 /* hash class keys */
  34 static struct lock_class_key batadv_orig_hash_lock_class_key;
  35
  36 static void batadv_purge_orig(struct work_struct *work);
  37
  38 /* returns 1 if they are the same originator */
  39 int batadv_compare_orig(const struct hlist_node *node, const void *data2)
  40 {
  41         const void *data1 = container_of(node, struct batadv_orig_node,
  42                                          hash_entry);
  43
  44         return (memcmp(data1, data2, ETH_ALEN) == 0 ? 1 : 0);
  45 }
  46
  47 /**
  48  * batadv_orig_node_vlan_get - get an orig_node_vlan object
  49  * @orig_node: the originator serving the VLAN
  50  * @vid: the VLAN identifier
  51  *
  52  * Returns the vlan object identified by vid and belonging to orig_node or NULL
  53  * if it does not exist.
  54  */
  55 struct batadv_orig_node_vlan *
  56 batadv_orig_node_vlan_get(struct batadv_orig_node *orig_node,
  57                           unsigned short vid)
  58 {
  59         struct batadv_orig_node_vlan *vlan = NULL, *tmp;
  60
  61         rcu_read_lock();
  62         list_for_each_entry_rcu(tmp, &orig_node->vlan_list, list) {
  63                 if (tmp->vid != vid)
  64                         continue;
  65
  66                 if (!atomic_inc_not_zero(&tmp->refcount))
  67                         continue;
  68
  69                 vlan = tmp;
  70
  71                 break;
  72         }
  73         rcu_read_unlock();
  74
  75         return vlan;
  76 }
  77
  78 /**
  79  * batadv_orig_node_vlan_new - search and possibly create an orig_node_vlan
  80  *  object
  81  * @orig_node: the originator serving the VLAN
  82  * @vid: the VLAN identifier
  83  *
  84  * Returns NULL in case of failure or the vlan object identified by vid and
  85  * belonging to orig_node otherwise. The object is created and added to the list
  86  * if it does not exist.
  87  *
  88  * The object is returned with refcounter increased by 1.
  89  */
  90 struct batadv_orig_node_vlan *
  91 batadv_orig_node_vlan_new(struct batadv_orig_node *orig_node,
  92                           unsigned short vid)
  93 {
  94         struct batadv_orig_node_vlan *vlan;
  95
  96         spin_lock_bh(&orig_node->vlan_list_lock);
  97
  98         /* first look if an object for this vid already exists */
  99         vlan = batadv_orig_node_vlan_get(orig_node, vid);
 100         if (vlan)
 101                 goto out;
 102
 103         vlan = kzalloc(sizeof(*vlan), GFP_ATOMIC);
 104         if (!vlan)
 105                 goto out;
 106
 107         atomic_set(&vlan->refcount, 2);
 108         vlan->vid = vid;
 109
 110         list_add_rcu(&vlan->list, &orig_node->vlan_list);
 111
 112 out:
 113         spin_unlock_bh(&orig_node->vlan_list_lock);
 114
 115         return vlan;
 116 }
 117
 118 /**
 119  * batadv_orig_node_vlan_free_ref - decrement the refcounter and possibly free
 120  *  the originator-vlan object
 121  * @orig_vlan: the originator-vlan object to release
 122  */
 123 void batadv_orig_node_vlan_free_ref(struct batadv_orig_node_vlan *orig_vlan)
 124 {
 125         if (atomic_dec_and_test(&orig_vlan->refcount))
 126                 kfree_rcu(orig_vlan, rcu);
 127 }
 128
 129 int batadv_originator_init(struct batadv_priv *bat_priv)
 130 {
 131         if (bat_priv->orig_hash)
 132                 return 0;
 133
 134         bat_priv->orig_hash = batadv_hash_new(1024);
 135
 136         if (!bat_priv->orig_hash)
 137                 goto err;
 138
 139         batadv_hash_set_lock_class(bat_priv->orig_hash,
 140                                    &batadv_orig_hash_lock_class_key);
 141
 142         INIT_DELAYED_WORK(&bat_priv->orig_work, batadv_purge_orig);
 143         queue_delayed_work(batadv_event_workqueue,
 144                            &bat_priv->orig_work,
 145                            msecs_to_jiffies(BATADV_ORIG_WORK_PERIOD));
 146
 147         return 0;
 148
 149 err:
 150         return -ENOMEM;
 151 }
 152
 153 void batadv_neigh_node_free_ref(struct batadv_neigh_node *neigh_node)
 154 {
 155         if (atomic_dec_and_test(&neigh_node->refcount))
 156                 kfree_rcu(neigh_node, rcu);
 157 }
 158
 159 /* increases the refcounter of a found router */
 160 struct batadv_neigh_node *
 161 batadv_orig_node_get_router(struct batadv_orig_node *orig_node)
 162 {
 163         struct batadv_neigh_node *router;
 164
 165         rcu_read_lock();
 166         router = rcu_dereference(orig_node->router);
 167
 168         if (router && !atomic_inc_not_zero(&router->refcount))
 169                 router = NULL;
 170
 171         rcu_read_unlock();
 172         return router;
 173 }
 174
 175 /**
 176  * batadv_neigh_node_new - create and init a new neigh_node object
 177  * @hard_iface: the interface where the neighbour is connected to
 178  * @neigh_addr: the mac address of the neighbour interface
 179  * @orig_node: originator object representing the neighbour
 180  *
 181  * Allocates a new neigh_node object and initialises all the generic fields.
 182  * Returns the new object or NULL on failure.
 183  */
 184 struct batadv_neigh_node *
 185 batadv_neigh_node_new(struct batadv_hard_iface *hard_iface,
 186                       const uint8_t *neigh_addr,
 187                       struct batadv_orig_node *orig_node)
 188 {
 189         struct batadv_neigh_node *neigh_node;
 190
 191         neigh_node = kzalloc(sizeof(*neigh_node), GFP_ATOMIC);
 192         if (!neigh_node)
 193                 goto out;
 194
 195         INIT_HLIST_NODE(&neigh_node->list);
 196
 197         memcpy(neigh_node->addr, neigh_addr, ETH_ALEN);
 198         neigh_node->if_incoming = hard_iface;
 199         neigh_node->orig_node = orig_node;
 200
 201         INIT_LIST_HEAD(&neigh_node->bonding_list);
 202
 203         /* extra reference for return */
 204         atomic_set(&neigh_node->refcount, 2);
 205
 206 out:
 207         return neigh_node;
 208 }
 209
 210 static void batadv_orig_node_free_rcu(struct rcu_head *rcu)
 211 {
 212         struct hlist_node *node_tmp;
 213         struct batadv_neigh_node *neigh_node, *tmp_neigh_node;
 214         struct batadv_orig_node *orig_node;
 215
 216         orig_node = container_of(rcu, struct batadv_orig_node, rcu);
 217
 218         spin_lock_bh(&orig_node->neigh_list_lock);
 219
 220         /* for all bonding members ... */
 221         list_for_each_entry_safe(neigh_node, tmp_neigh_node,
 222                                  &orig_node->bond_list, bonding_list) {
 223                 list_del_rcu(&neigh_node->bonding_list);
 224                 batadv_neigh_node_free_ref(neigh_node);
 225         }
 226
 227         /* for all neighbors towards this originator ... */
 228         hlist_for_each_entry_safe(neigh_node, node_tmp,
 229                                   &orig_node->neigh_list, list) {
 230                 hlist_del_rcu(&neigh_node->list);
 231                 batadv_neigh_node_free_ref(neigh_node);
 232         }
 233
 234         spin_unlock_bh(&orig_node->neigh_list_lock);
 235
 236         /* Free nc_nodes */
 237         batadv_nc_purge_orig(orig_node->bat_priv, orig_node, NULL);
 238
 239         batadv_frag_purge_orig(orig_node, NULL);
 240
 241         batadv_tt_global_del_orig(orig_node->bat_priv, orig_node, -1,
 242                                   "originator timed out");
 243
 244         if (orig_node->bat_priv->bat_algo_ops->bat_orig_free)
 245                 orig_node->bat_priv->bat_algo_ops->bat_orig_free(orig_node);
 246
 247         kfree(orig_node->tt_buff);
 248         kfree(orig_node);
 249 }
 250
 251 /**
 252  * batadv_orig_node_free_ref - decrement the orig node refcounter and possibly
 253  * schedule an rcu callback for freeing it
 254  * @orig_node: the orig node to free
 255  */
 256 void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node)
 257 {
 258         if (atomic_dec_and_test(&orig_node->refcount))
 259                 call_rcu(&orig_node->rcu, batadv_orig_node_free_rcu);
 260 }
 261
 262 /**
 263  * batadv_orig_node_free_ref_now - decrement the orig node refcounter and
 264  * possibly free it (without rcu callback)
 265  * @orig_node: the orig node to free
 266  */
 267 void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node)
 268 {
 269         if (atomic_dec_and_test(&orig_node->refcount))
 270                 batadv_orig_node_free_rcu(&orig_node->rcu);
 271 }
 272
 273 void batadv_originator_free(struct batadv_priv *bat_priv)
 274 {
 275         struct batadv_hashtable *hash = bat_priv->orig_hash;
 276         struct hlist_node *node_tmp;
 277         struct hlist_head *head;
 278         spinlock_t *list_lock; /* spinlock to protect write access */
 279         struct batadv_orig_node *orig_node;
 280         uint32_t i;
 281
 282         if (!hash)
 283                 return;
 284
 285         cancel_delayed_work_sync(&bat_priv->orig_work);
 286
 287         bat_priv->orig_hash = NULL;
 288
 289         for (i = 0; i < hash->size; i++) {
 290                 head = &hash->table[i];
 291                 list_lock = &hash->list_locks[i];
 292
 293                 spin_lock_bh(list_lock);
 294                 hlist_for_each_entry_safe(orig_node, node_tmp,
 295                                           head, hash_entry) {
 296                         hlist_del_rcu(&orig_node->hash_entry);
 297                         batadv_orig_node_free_ref(orig_node);
 298                 }
 299                 spin_unlock_bh(list_lock);
 300         }
 301
 302         batadv_hash_destroy(hash);
 303 }
 304
 305 /**
 306  * batadv_orig_node_new - creates a new orig_node
 307  * @bat_priv: the bat priv with all the soft interface information
 308  * @addr: the mac address of the originator
 309  *
 310  * Creates a new originator object and initialise all the generic fields.
 311  * The new object is not added to the originator list.
 312  * Returns the newly created object or NULL on failure.
 313  */
 314 struct batadv_orig_node *batadv_orig_node_new(struct batadv_priv *bat_priv,
 315                                               const uint8_t *addr)
 316 {
 317         struct batadv_orig_node *orig_node;
 318         struct batadv_orig_node_vlan *vlan;
 319         unsigned long reset_time;
 320         int i;
 321
 322         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 323                    "Creating new originator: %pM\n", addr);
 324
 325         orig_node = kzalloc(sizeof(*orig_node), GFP_ATOMIC);
 326         if (!orig_node)
 327                 return NULL;
 328
 329         INIT_HLIST_HEAD(&orig_node->neigh_list);
 330         INIT_LIST_HEAD(&orig_node->bond_list);
 331         INIT_LIST_HEAD(&orig_node->vlan_list);
 332         spin_lock_init(&orig_node->bcast_seqno_lock);
 333         spin_lock_init(&orig_node->neigh_list_lock);
 334         spin_lock_init(&orig_node->tt_buff_lock);
 335         spin_lock_init(&orig_node->tt_lock);
 336         spin_lock_init(&orig_node->vlan_list_lock);
 337
 338         batadv_nc_init_orig(orig_node);
 339
 340         /* extra reference for return */
 341         atomic_set(&orig_node->refcount, 2);
 342
 343         orig_node->tt_initialised = false;
 344         orig_node->bat_priv = bat_priv;
 345         memcpy(orig_node->orig, addr, ETH_ALEN);
 346         batadv_dat_init_orig_node_addr(orig_node);
 347         orig_node->router = NULL;
 348         atomic_set(&orig_node->last_ttvn, 0);
 349         orig_node->tt_buff = NULL;
 350         orig_node->tt_buff_len = 0;
 351         reset_time = jiffies - 1 - msecs_to_jiffies(BATADV_RESET_PROTECTION_MS);
 352         orig_node->bcast_seqno_reset = reset_time;
 353         orig_node->batman_seqno_reset = reset_time;
 354
 355         atomic_set(&orig_node->bond_candidates, 0);
 356
 357         /* create a vlan object for the "untagged" LAN */
 358         vlan = batadv_orig_node_vlan_new(orig_node, BATADV_NO_FLAGS);
 359         if (!vlan)
 360                 goto free_orig_node;
 361         /* batadv_orig_node_vlan_new() increases the refcounter.
 362          * Immediately release vlan since it is not needed anymore in this
 363          * context
 364          */
 365         batadv_orig_node_vlan_free_ref(vlan);
 366
 367         for (i = 0; i < BATADV_FRAG_BUFFER_COUNT; i++) {
 368                 INIT_HLIST_HEAD(&orig_node->fragments[i].head);
 369                 spin_lock_init(&orig_node->fragments[i].lock);
 370                 orig_node->fragments[i].size = 0;
 371         }
 372
 373         return orig_node;
 374 free_orig_node:
 375         kfree(orig_node);
 376         return NULL;
 377 }
 378
 379 static bool
 380 batadv_purge_orig_neighbors(struct batadv_priv *bat_priv,
 381                             struct batadv_orig_node *orig_node,
 382                             struct batadv_neigh_node **best_neigh)
 383 {
 384         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 385         struct hlist_node *node_tmp;
 386         struct batadv_neigh_node *neigh_node;
 387         bool neigh_purged = false;
 388         unsigned long last_seen;
 389         struct batadv_hard_iface *if_incoming;
 390
 391         *best_neigh = NULL;
 392
 393         spin_lock_bh(&orig_node->neigh_list_lock);
 394
 395         /* for all neighbors towards this originator ... */
 396         hlist_for_each_entry_safe(neigh_node, node_tmp,
 397                                   &orig_node->neigh_list, list) {
 398                 last_seen = neigh_node->last_seen;
 399                 if_incoming = neigh_node->if_incoming;
 400
 401                 if ((batadv_has_timed_out(last_seen, BATADV_PURGE_TIMEOUT)) ||
 402                     (if_incoming->if_status == BATADV_IF_INACTIVE) ||
 403                     (if_incoming->if_status == BATADV_IF_NOT_IN_USE) ||
 404                     (if_incoming->if_status == BATADV_IF_TO_BE_REMOVED)) {
 405                         if ((if_incoming->if_status == BATADV_IF_INACTIVE) ||
 406                             (if_incoming->if_status == BATADV_IF_NOT_IN_USE) ||
 407                             (if_incoming->if_status == BATADV_IF_TO_BE_REMOVED))
 408                                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 409                                            "neighbor purge: originator %pM, neighbor: %pM, iface: %s\n",
 410                                            orig_node->orig, neigh_node->addr,
 411                                            if_incoming->net_dev->name);
 412                         else
 413                                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 414                                            "neighbor timeout: originator %pM, neighbor: %pM, last_seen: %u\n",
 415                                            orig_node->orig, neigh_node->addr,
 416                                            jiffies_to_msecs(last_seen));
 417
 418                         neigh_purged = true;
 419
 420                         hlist_del_rcu(&neigh_node->list);
 421                         batadv_bonding_candidate_del(orig_node, neigh_node);
 422                         batadv_neigh_node_free_ref(neigh_node);
 423                 } else {
 424                         /* store the best_neighbour if this is the first
 425                          * iteration or if a better neighbor has been found
 426                          */
 427                         if (!*best_neigh ||
 428                             bao->bat_neigh_cmp(neigh_node, *best_neigh) > 0)
 429                                 *best_neigh = neigh_node;
 430                 }
 431         }
 432
 433         spin_unlock_bh(&orig_node->neigh_list_lock);
 434         return neigh_purged;
 435 }
 436
 437 static bool batadv_purge_orig_node(struct batadv_priv *bat_priv,
 438                                    struct batadv_orig_node *orig_node)
 439 {
 440         struct batadv_neigh_node *best_neigh_node;
 441
 442         if (batadv_has_timed_out(orig_node->last_seen,
 443                                  2 * BATADV_PURGE_TIMEOUT)) {
 444                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 445                            "Originator timeout: originator %pM, last_seen %u\n",
 446                            orig_node->orig,
 447                            jiffies_to_msecs(orig_node->last_seen));
 448                 return true;
 449         } else {
 450                 if (batadv_purge_orig_neighbors(bat_priv, orig_node,
 451                                                 &best_neigh_node))
 452                         batadv_update_route(bat_priv, orig_node,
 453                                             best_neigh_node);
 454         }
 455
 456         return false;
 457 }
 458
 459 static void _batadv_purge_orig(struct batadv_priv *bat_priv)
 460 {
 461         struct batadv_hashtable *hash = bat_priv->orig_hash;
 462         struct hlist_node *node_tmp;
 463         struct hlist_head *head;
 464         spinlock_t *list_lock; /* spinlock to protect write access */
 465         struct batadv_orig_node *orig_node;
 466         uint32_t i;
 467
 468         if (!hash)
 469                 return;
 470
 471         /* for all origins... */
 472         for (i = 0; i < hash->size; i++) {
 473                 head = &hash->table[i];
 474                 list_lock = &hash->list_locks[i];
 475
 476                 spin_lock_bh(list_lock);
 477                 hlist_for_each_entry_safe(orig_node, node_tmp,
 478                                           head, hash_entry) {
 479                         if (batadv_purge_orig_node(bat_priv, orig_node)) {
 480                                 batadv_gw_node_delete(bat_priv, orig_node);
 481                                 hlist_del_rcu(&orig_node->hash_entry);
 482                                 batadv_orig_node_free_ref(orig_node);
 483                                 continue;
 484                         }
 485
 486                         batadv_frag_purge_orig(orig_node,
 487                                                batadv_frag_check_entry);
 488                 }
 489                 spin_unlock_bh(list_lock);
 490         }
 491
 492         batadv_gw_node_purge(bat_priv);
 493         batadv_gw_election(bat_priv);
 494 }
 495
 496 static void batadv_purge_orig(struct work_struct *work)
 497 {
 498         struct delayed_work *delayed_work;
 499         struct batadv_priv *bat_priv;
 500
 501         delayed_work = container_of(work, struct delayed_work, work);
 502         bat_priv = container_of(delayed_work, struct batadv_priv, orig_work);
 503         _batadv_purge_orig(bat_priv);
 504         queue_delayed_work(batadv_event_workqueue,
 505                            &bat_priv->orig_work,
 506                            msecs_to_jiffies(BATADV_ORIG_WORK_PERIOD));
 507 }
 508
 509 void batadv_purge_orig_ref(struct batadv_priv *bat_priv)
 510 {
 511         _batadv_purge_orig(bat_priv);
 512 }
 513
 514 int batadv_orig_seq_print_text(struct seq_file *seq, void *offset)
 515 {
 516         struct net_device *net_dev = (struct net_device *)seq->private;
 517         struct batadv_priv *bat_priv = netdev_priv(net_dev);
 518         struct batadv_hard_iface *primary_if;
 519
 520         primary_if = batadv_seq_print_text_primary_if_get(seq);
 521         if (!primary_if)
 522                 return 0;
 523
 524         seq_printf(seq, "[B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s %s)]\n",
 525                    BATADV_SOURCE_VERSION, primary_if->net_dev->name,
 526                    primary_if->net_dev->dev_addr, net_dev->name,
 527                    bat_priv->bat_algo_ops->name);
 528
 529         batadv_hardif_free_ref(primary_if);
 530
 531         if (!bat_priv->bat_algo_ops->bat_orig_print) {
 532                 seq_puts(seq,
 533                          "No printing function for this routing protocol\n");
 534                 return 0;
 535         }
 536
 537         bat_priv->bat_algo_ops->bat_orig_print(bat_priv, seq);
 538
 539         return 0;
 540 }
 541
 542 int batadv_orig_hash_add_if(struct batadv_hard_iface *hard_iface,
 543                             int max_if_num)
 544 {
 545         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 546         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 547         struct batadv_hashtable *hash = bat_priv->orig_hash;
 548         struct hlist_head *head;
 549         struct batadv_orig_node *orig_node;
 550         uint32_t i;
 551         int ret;
 552
 553         /* resize all orig nodes because orig_node->bcast_own(_sum) depend on
 554          * if_num
 555          */
 556         for (i = 0; i < hash->size; i++) {
 557                 head = &hash->table[i];
 558
 559                 rcu_read_lock();
 560                 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
 561                         ret = 0;
 562                         if (bao->bat_orig_add_if)
 563                                 ret = bao->bat_orig_add_if(orig_node,
 564                                                            max_if_num);
 565                         if (ret == -ENOMEM)
 566                                 goto err;
 567                 }
 568                 rcu_read_unlock();
 569         }
 570
 571         return 0;
 572
 573 err:
 574         rcu_read_unlock();
 575         return -ENOMEM;
 576 }
 577
 578 int batadv_orig_hash_del_if(struct batadv_hard_iface *hard_iface,
 579                             int max_if_num)
 580 {
 581         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 582         struct batadv_hashtable *hash = bat_priv->orig_hash;
 583         struct hlist_head *head;
 584         struct batadv_hard_iface *hard_iface_tmp;
 585         struct batadv_orig_node *orig_node;
 586         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 587         uint32_t i;
 588         int ret;
 589
 590         /* resize all orig nodes because orig_node->bcast_own(_sum) depend on
 591          * if_num
 592          */
 593         for (i = 0; i < hash->size; i++) {
 594                 head = &hash->table[i];
 595
 596                 rcu_read_lock();
 597                 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
 598                         ret = 0;
 599                         if (bao->bat_orig_del_if)
 600                                 ret = bao->bat_orig_del_if(orig_node,
 601                                                            max_if_num,
 602                                                            hard_iface->if_num);
 603                         if (ret == -ENOMEM)
 604                                 goto err;
 605                 }
 606                 rcu_read_unlock();
 607         }
 608
 609         /* renumber remaining batman interfaces _inside_ of orig_hash_lock */
 610         rcu_read_lock();
 611         list_for_each_entry_rcu(hard_iface_tmp, &batadv_hardif_list, list) {
 612                 if (hard_iface_tmp->if_status == BATADV_IF_NOT_IN_USE)
 613                         continue;
 614
 615                 if (hard_iface == hard_iface_tmp)
 616                         continue;
 617
 618                 if (hard_iface->soft_iface != hard_iface_tmp->soft_iface)
 619                         continue;
 620
 621                 if (hard_iface_tmp->if_num > hard_iface->if_num)
 622                         hard_iface_tmp->if_num--;
 623         }
 624         rcu_read_unlock();
 625
 626         hard_iface->if_num = -1;
 627         return 0;
 628
 629 err:
 630         rcu_read_unlock();
 631         return -ENOMEM;
 632 }