net/batman-adv/originator.c

   1 /*
   2  * Copyright (C) 2009-2012 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 "originator.h"
  24 #include "hash.h"
  25 #include "translation-table.h"
  26 #include "routing.h"
  27 #include "gateway_client.h"
  28 #include "hard-interface.h"
  29 #include "unicast.h"
  30 #include "soft-interface.h"
  31 #include "bridge_loop_avoidance.h"
  32
  33 static void purge_orig(struct work_struct *work);
  34
  35 static void start_purge_timer(struct bat_priv *bat_priv)
  36 {
  37         INIT_DELAYED_WORK(&bat_priv->orig_work, purge_orig);
  38         queue_delayed_work(bat_event_workqueue, &bat_priv->orig_work, 1 * HZ);
  39 }
  40
  41 /* returns 1 if they are the same originator */
  42 static int compare_orig(const struct hlist_node *node, const void *data2)
  43 {
  44         const void *data1 = container_of(node, struct orig_node, hash_entry);
  45
  46         return (memcmp(data1, data2, ETH_ALEN) == 0 ? 1 : 0);
  47 }
  48
  49 int originator_init(struct bat_priv *bat_priv)
  50 {
  51         if (bat_priv->orig_hash)
  52                 return 1;
  53
  54         bat_priv->orig_hash = hash_new(1024);
  55
  56         if (!bat_priv->orig_hash)
  57                 goto err;
  58
  59         start_purge_timer(bat_priv);
  60         return 1;
  61
  62 err:
  63         return 0;
  64 }
  65
  66 void neigh_node_free_ref(struct neigh_node *neigh_node)
  67 {
  68         if (atomic_dec_and_test(&neigh_node->refcount))
  69                 kfree_rcu(neigh_node, rcu);
  70 }
  71
  72 /* increases the refcounter of a found router */
  73 struct neigh_node *orig_node_get_router(struct orig_node *orig_node)
  74 {
  75         struct neigh_node *router;
  76
  77         rcu_read_lock();
  78         router = rcu_dereference(orig_node->router);
  79
  80         if (router && !atomic_inc_not_zero(&router->refcount))
  81                 router = NULL;
  82
  83         rcu_read_unlock();
  84         return router;
  85 }
  86
  87 struct neigh_node *create_neighbor(struct orig_node *orig_node,
  88                                    struct orig_node *orig_neigh_node,
  89                                    const uint8_t *neigh,
  90                                    struct hard_iface *if_incoming)
  91 {
  92         struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
  93         struct neigh_node *neigh_node;
  94
  95         bat_dbg(DBG_BATMAN, bat_priv,
  96                 "Creating new last-hop neighbor of originator\n");
  97
  98         neigh_node = kzalloc(sizeof(*neigh_node), GFP_ATOMIC);
  99         if (!neigh_node)
 100                 return NULL;
 101
 102         INIT_HLIST_NODE(&neigh_node->list);
 103         INIT_LIST_HEAD(&neigh_node->bonding_list);
 104         spin_lock_init(&neigh_node->tq_lock);
 105
 106         memcpy(neigh_node->addr, neigh, ETH_ALEN);
 107         neigh_node->orig_node = orig_neigh_node;
 108         neigh_node->if_incoming = if_incoming;
 109
 110         /* extra reference for return */
 111         atomic_set(&neigh_node->refcount, 2);
 112
 113         spin_lock_bh(&orig_node->neigh_list_lock);
 114         hlist_add_head_rcu(&neigh_node->list, &orig_node->neigh_list);
 115         spin_unlock_bh(&orig_node->neigh_list_lock);
 116         return neigh_node;
 117 }
 118
 119 static void orig_node_free_rcu(struct rcu_head *rcu)
 120 {
 121         struct hlist_node *node, *node_tmp;
 122         struct neigh_node *neigh_node, *tmp_neigh_node;
 123         struct orig_node *orig_node;
 124
 125         orig_node = container_of(rcu, struct orig_node, rcu);
 126
 127         spin_lock_bh(&orig_node->neigh_list_lock);
 128
 129         /* for all bonding members ... */
 130         list_for_each_entry_safe(neigh_node, tmp_neigh_node,
 131                                  &orig_node->bond_list, bonding_list) {
 132                 list_del_rcu(&neigh_node->bonding_list);
 133                 neigh_node_free_ref(neigh_node);
 134         }
 135
 136         /* for all neighbors towards this originator ... */
 137         hlist_for_each_entry_safe(neigh_node, node, node_tmp,
 138                                   &orig_node->neigh_list, list) {
 139                 hlist_del_rcu(&neigh_node->list);
 140                 neigh_node_free_ref(neigh_node);
 141         }
 142
 143         spin_unlock_bh(&orig_node->neigh_list_lock);
 144
 145         frag_list_free(&orig_node->frag_list);
 146         tt_global_del_orig(orig_node->bat_priv, orig_node,
 147                            "originator timed out");
 148
 149         kfree(orig_node->tt_buff);
 150         kfree(orig_node->bcast_own);
 151         kfree(orig_node->bcast_own_sum);
 152         kfree(orig_node);
 153 }
 154
 155 void orig_node_free_ref(struct orig_node *orig_node)
 156 {
 157         if (atomic_dec_and_test(&orig_node->refcount))
 158                 call_rcu(&orig_node->rcu, orig_node_free_rcu);
 159 }
 160
 161 void originator_free(struct bat_priv *bat_priv)
 162 {
 163         struct hashtable_t *hash = bat_priv->orig_hash;
 164         struct hlist_node *node, *node_tmp;
 165         struct hlist_head *head;
 166         spinlock_t *list_lock; /* spinlock to protect write access */
 167         struct orig_node *orig_node;
 168         uint32_t i;
 169
 170         if (!hash)
 171                 return;
 172
 173         cancel_delayed_work_sync(&bat_priv->orig_work);
 174
 175         bat_priv->orig_hash = NULL;
 176
 177         for (i = 0; i < hash->size; i++) {
 178                 head = &hash->table[i];
 179                 list_lock = &hash->list_locks[i];
 180
 181                 spin_lock_bh(list_lock);
 182                 hlist_for_each_entry_safe(orig_node, node, node_tmp,
 183                                           head, hash_entry) {
 184
 185                         hlist_del_rcu(node);
 186                         orig_node_free_ref(orig_node);
 187                 }
 188                 spin_unlock_bh(list_lock);
 189         }
 190
 191         hash_destroy(hash);
 192 }
 193
 194 /* this function finds or creates an originator entry for the given
 195  * address if it does not exits */
 196 struct orig_node *get_orig_node(struct bat_priv *bat_priv, const uint8_t *addr)
 197 {
 198         struct orig_node *orig_node;
 199         int size;
 200         int hash_added;
 201
 202         orig_node = orig_hash_find(bat_priv, addr);
 203         if (orig_node)
 204                 return orig_node;
 205
 206         bat_dbg(DBG_BATMAN, bat_priv,
 207                 "Creating new originator: %pM\n", addr);
 208
 209         orig_node = kzalloc(sizeof(*orig_node), GFP_ATOMIC);
 210         if (!orig_node)
 211                 return NULL;
 212
 213         INIT_HLIST_HEAD(&orig_node->neigh_list);
 214         INIT_LIST_HEAD(&orig_node->bond_list);
 215         spin_lock_init(&orig_node->ogm_cnt_lock);
 216         spin_lock_init(&orig_node->bcast_seqno_lock);
 217         spin_lock_init(&orig_node->neigh_list_lock);
 218         spin_lock_init(&orig_node->tt_buff_lock);
 219
 220         /* extra reference for return */
 221         atomic_set(&orig_node->refcount, 2);
 222
 223         orig_node->tt_initialised = false;
 224         orig_node->tt_poss_change = false;
 225         orig_node->bat_priv = bat_priv;
 226         memcpy(orig_node->orig, addr, ETH_ALEN);
 227         orig_node->router = NULL;
 228         orig_node->tt_crc = 0;
 229         atomic_set(&orig_node->last_ttvn, 0);
 230         orig_node->tt_buff = NULL;
 231         orig_node->tt_buff_len = 0;
 232         atomic_set(&orig_node->tt_size, 0);
 233         orig_node->bcast_seqno_reset = jiffies - 1
 234                                         - msecs_to_jiffies(RESET_PROTECTION_MS);
 235         orig_node->batman_seqno_reset = jiffies - 1
 236                                         - msecs_to_jiffies(RESET_PROTECTION_MS);
 237
 238         atomic_set(&orig_node->bond_candidates, 0);
 239
 240         size = bat_priv->num_ifaces * sizeof(unsigned long) * NUM_WORDS;
 241
 242         orig_node->bcast_own = kzalloc(size, GFP_ATOMIC);
 243         if (!orig_node->bcast_own)
 244                 goto free_orig_node;
 245
 246         size = bat_priv->num_ifaces * sizeof(uint8_t);
 247         orig_node->bcast_own_sum = kzalloc(size, GFP_ATOMIC);
 248
 249         INIT_LIST_HEAD(&orig_node->frag_list);
 250         orig_node->last_frag_packet = 0;
 251
 252         if (!orig_node->bcast_own_sum)
 253                 goto free_bcast_own;
 254
 255         hash_added = hash_add(bat_priv->orig_hash, compare_orig,
 256                               choose_orig, orig_node, &orig_node->hash_entry);
 257         if (hash_added != 0)
 258                 goto free_bcast_own_sum;
 259
 260         return orig_node;
 261 free_bcast_own_sum:
 262         kfree(orig_node->bcast_own_sum);
 263 free_bcast_own:
 264         kfree(orig_node->bcast_own);
 265 free_orig_node:
 266         kfree(orig_node);
 267         return NULL;
 268 }
 269
 270 static bool purge_orig_neighbors(struct bat_priv *bat_priv,
 271                                  struct orig_node *orig_node,
 272                                  struct neigh_node **best_neigh_node)
 273 {
 274         struct hlist_node *node, *node_tmp;
 275         struct neigh_node *neigh_node;
 276         bool neigh_purged = false;
 277
 278         *best_neigh_node = NULL;
 279
 280         spin_lock_bh(&orig_node->neigh_list_lock);
 281
 282         /* for all neighbors towards this originator ... */
 283         hlist_for_each_entry_safe(neigh_node, node, node_tmp,
 284                                   &orig_node->neigh_list, list) {
 285
 286                 if ((has_timed_out(neigh_node->last_valid, PURGE_TIMEOUT)) ||
 287                     (neigh_node->if_incoming->if_status == IF_INACTIVE) ||
 288                     (neigh_node->if_incoming->if_status == IF_NOT_IN_USE) ||
 289                     (neigh_node->if_incoming->if_status == IF_TO_BE_REMOVED)) {
 290
 291                         if ((neigh_node->if_incoming->if_status ==
 292                                                                 IF_INACTIVE) ||
 293                             (neigh_node->if_incoming->if_status ==
 294                                                         IF_NOT_IN_USE) ||
 295                             (neigh_node->if_incoming->if_status ==
 296                                                         IF_TO_BE_REMOVED))
 297                                 bat_dbg(DBG_BATMAN, bat_priv,
 298                                         "neighbor purge: originator %pM, neighbor: %pM, iface: %s\n",
 299                                         orig_node->orig, neigh_node->addr,
 300                                         neigh_node->if_incoming->net_dev->name);
 301                         else
 302                                 bat_dbg(DBG_BATMAN, bat_priv,
 303                                         "neighbor timeout: originator %pM, neighbor: %pM, last_valid: %lu\n",
 304                                         orig_node->orig, neigh_node->addr,
 305                                         (neigh_node->last_valid / HZ));
 306
 307                         neigh_purged = true;
 308
 309                         hlist_del_rcu(&neigh_node->list);
 310                         bonding_candidate_del(orig_node, neigh_node);
 311                         neigh_node_free_ref(neigh_node);
 312                 } else {
 313                         if ((!*best_neigh_node) ||
 314                             (neigh_node->tq_avg > (*best_neigh_node)->tq_avg))
 315                                 *best_neigh_node = neigh_node;
 316                 }
 317         }
 318
 319         spin_unlock_bh(&orig_node->neigh_list_lock);
 320         return neigh_purged;
 321 }
 322
 323 static bool purge_orig_node(struct bat_priv *bat_priv,
 324                             struct orig_node *orig_node)
 325 {
 326         struct neigh_node *best_neigh_node;
 327
 328         if (has_timed_out(orig_node->last_valid, 2 * PURGE_TIMEOUT)) {
 329                 bat_dbg(DBG_BATMAN, bat_priv,
 330                         "Originator timeout: originator %pM, last_valid %lu\n",
 331                         orig_node->orig, (orig_node->last_valid / HZ));
 332                 return true;
 333         } else {
 334                 if (purge_orig_neighbors(bat_priv, orig_node,
 335                                          &best_neigh_node))
 336                         update_route(bat_priv, orig_node, best_neigh_node);
 337         }
 338
 339         return false;
 340 }
 341
 342 static void _purge_orig(struct bat_priv *bat_priv)
 343 {
 344         struct hashtable_t *hash = bat_priv->orig_hash;
 345         struct hlist_node *node, *node_tmp;
 346         struct hlist_head *head;
 347         spinlock_t *list_lock; /* spinlock to protect write access */
 348         struct orig_node *orig_node;
 349         uint32_t i;
 350
 351         if (!hash)
 352                 return;
 353
 354         /* for all origins... */
 355         for (i = 0; i < hash->size; i++) {
 356                 head = &hash->table[i];
 357                 list_lock = &hash->list_locks[i];
 358
 359                 spin_lock_bh(list_lock);
 360                 hlist_for_each_entry_safe(orig_node, node, node_tmp,
 361                                           head, hash_entry) {
 362                         if (purge_orig_node(bat_priv, orig_node)) {
 363                                 if (orig_node->gw_flags)
 364                                         gw_node_delete(bat_priv, orig_node);
 365                                 hlist_del_rcu(node);
 366                                 orig_node_free_ref(orig_node);
 367                                 continue;
 368                         }
 369
 370                         if (has_timed_out(orig_node->last_frag_packet,
 371                                           FRAG_TIMEOUT))
 372                                 frag_list_free(&orig_node->frag_list);
 373                 }
 374                 spin_unlock_bh(list_lock);
 375         }
 376
 377         gw_node_purge(bat_priv);
 378         gw_election(bat_priv);
 379 }
 380
 381 static void purge_orig(struct work_struct *work)
 382 {
 383         struct delayed_work *delayed_work =
 384                 container_of(work, struct delayed_work, work);
 385         struct bat_priv *bat_priv =
 386                 container_of(delayed_work, struct bat_priv, orig_work);
 387
 388         _purge_orig(bat_priv);
 389         start_purge_timer(bat_priv);
 390 }
 391
 392 void purge_orig_ref(struct bat_priv *bat_priv)
 393 {
 394         _purge_orig(bat_priv);
 395 }
 396
 397 int orig_seq_print_text(struct seq_file *seq, void *offset)
 398 {
 399         struct net_device *net_dev = (struct net_device *)seq->private;
 400         struct bat_priv *bat_priv = netdev_priv(net_dev);
 401         struct hashtable_t *hash = bat_priv->orig_hash;
 402         struct hlist_node *node, *node_tmp;
 403         struct hlist_head *head;
 404         struct hard_iface *primary_if;
 405         struct orig_node *orig_node;
 406         struct neigh_node *neigh_node, *neigh_node_tmp;
 407         int batman_count = 0;
 408         int last_seen_secs;
 409         int last_seen_msecs;
 410         uint32_t i;
 411         int ret = 0;
 412
 413         primary_if = primary_if_get_selected(bat_priv);
 414
 415         if (!primary_if) {
 416                 ret = seq_printf(seq,
 417                                  "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
 418                                  net_dev->name);
 419                 goto out;
 420         }
 421
 422         if (primary_if->if_status != IF_ACTIVE) {
 423                 ret = seq_printf(seq,
 424                                  "BATMAN mesh %s disabled - primary interface not active\n",
 425                                  net_dev->name);
 426                 goto out;
 427         }
 428
 429         seq_printf(seq, "[B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
 430                    SOURCE_VERSION, primary_if->net_dev->name,
 431                    primary_if->net_dev->dev_addr, net_dev->name);
 432         seq_printf(seq, "  %-15s %s (%s/%i) %17s [%10s]: %20s ...\n",
 433                    "Originator", "last-seen", "#", TQ_MAX_VALUE, "Nexthop",
 434                    "outgoingIF", "Potential nexthops");
 435
 436         for (i = 0; i < hash->size; i++) {
 437                 head = &hash->table[i];
 438
 439                 rcu_read_lock();
 440                 hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
 441                         neigh_node = orig_node_get_router(orig_node);
 442                         if (!neigh_node)
 443                                 continue;
 444
 445                         if (neigh_node->tq_avg == 0)
 446                                 goto next;
 447
 448                         last_seen_secs = jiffies_to_msecs(jiffies -
 449                                                 orig_node->last_valid) / 1000;
 450                         last_seen_msecs = jiffies_to_msecs(jiffies -
 451                                                 orig_node->last_valid) % 1000;
 452
 453                         seq_printf(seq, "%pM %4i.%03is   (%3i) %pM [%10s]:",
 454                                    orig_node->orig, last_seen_secs,
 455                                    last_seen_msecs, neigh_node->tq_avg,
 456                                    neigh_node->addr,
 457                                    neigh_node->if_incoming->net_dev->name);
 458
 459                         hlist_for_each_entry_rcu(neigh_node_tmp, node_tmp,
 460                                                  &orig_node->neigh_list, list) {
 461                                 seq_printf(seq, " %pM (%3i)",
 462                                            neigh_node_tmp->addr,
 463                                            neigh_node_tmp->tq_avg);
 464                         }
 465
 466                         seq_printf(seq, "\n");
 467                         batman_count++;
 468
 469 next:
 470                         neigh_node_free_ref(neigh_node);
 471                 }
 472                 rcu_read_unlock();
 473         }
 474
 475         if (batman_count == 0)
 476                 seq_printf(seq, "No batman nodes in range ...\n");
 477
 478 out:
 479         if (primary_if)
 480                 hardif_free_ref(primary_if);
 481         return ret;
 482 }
 483
 484 static int orig_node_add_if(struct orig_node *orig_node, int max_if_num)
 485 {
 486         void *data_ptr;
 487
 488         data_ptr = kmalloc(max_if_num * sizeof(unsigned long) * NUM_WORDS,
 489                            GFP_ATOMIC);
 490         if (!data_ptr)
 491                 return -1;
 492
 493         memcpy(data_ptr, orig_node->bcast_own,
 494                (max_if_num - 1) * sizeof(unsigned long) * NUM_WORDS);
 495         kfree(orig_node->bcast_own);
 496         orig_node->bcast_own = data_ptr;
 497
 498         data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC);
 499         if (!data_ptr)
 500                 return -1;
 501
 502         memcpy(data_ptr, orig_node->bcast_own_sum,
 503                (max_if_num - 1) * sizeof(uint8_t));
 504         kfree(orig_node->bcast_own_sum);
 505         orig_node->bcast_own_sum = data_ptr;
 506
 507         return 0;
 508 }
 509
 510 int orig_hash_add_if(struct hard_iface *hard_iface, int max_if_num)
 511 {
 512         struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 513         struct hashtable_t *hash = bat_priv->orig_hash;
 514         struct hlist_node *node;
 515         struct hlist_head *head;
 516         struct orig_node *orig_node;
 517         uint32_t i;
 518         int ret;
 519
 520         /* resize all orig nodes because orig_node->bcast_own(_sum) depend on
 521          * if_num */
 522         for (i = 0; i < hash->size; i++) {
 523                 head = &hash->table[i];
 524
 525                 rcu_read_lock();
 526                 hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
 527                         spin_lock_bh(&orig_node->ogm_cnt_lock);
 528                         ret = orig_node_add_if(orig_node, max_if_num);
 529                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
 530
 531                         if (ret == -1)
 532                                 goto err;
 533                 }
 534                 rcu_read_unlock();
 535         }
 536
 537         return 0;
 538
 539 err:
 540         rcu_read_unlock();
 541         return -ENOMEM;
 542 }
 543
 544 static int orig_node_del_if(struct orig_node *orig_node,
 545                      int max_if_num, int del_if_num)
 546 {
 547         void *data_ptr = NULL;
 548         int chunk_size;
 549
 550         /* last interface was removed */
 551         if (max_if_num == 0)
 552                 goto free_bcast_own;
 553
 554         chunk_size = sizeof(unsigned long) * NUM_WORDS;
 555         data_ptr = kmalloc(max_if_num * chunk_size, GFP_ATOMIC);
 556         if (!data_ptr)
 557                 return -1;
 558
 559         /* copy first part */
 560         memcpy(data_ptr, orig_node->bcast_own, del_if_num * chunk_size);
 561
 562         /* copy second part */
 563         memcpy((char *)data_ptr + del_if_num * chunk_size,
 564                orig_node->bcast_own + ((del_if_num + 1) * chunk_size),
 565                (max_if_num - del_if_num) * chunk_size);
 566
 567 free_bcast_own:
 568         kfree(orig_node->bcast_own);
 569         orig_node->bcast_own = data_ptr;
 570
 571         if (max_if_num == 0)
 572                 goto free_own_sum;
 573
 574         data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC);
 575         if (!data_ptr)
 576                 return -1;
 577
 578         memcpy(data_ptr, orig_node->bcast_own_sum,
 579                del_if_num * sizeof(uint8_t));
 580
 581         memcpy((char *)data_ptr + del_if_num * sizeof(uint8_t),
 582                orig_node->bcast_own_sum + ((del_if_num + 1) * sizeof(uint8_t)),
 583                (max_if_num - del_if_num) * sizeof(uint8_t));
 584
 585 free_own_sum:
 586         kfree(orig_node->bcast_own_sum);
 587         orig_node->bcast_own_sum = data_ptr;
 588
 589         return 0;
 590 }
 591
 592 int orig_hash_del_if(struct hard_iface *hard_iface, int max_if_num)
 593 {
 594         struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 595         struct hashtable_t *hash = bat_priv->orig_hash;
 596         struct hlist_node *node;
 597         struct hlist_head *head;
 598         struct hard_iface *hard_iface_tmp;
 599         struct orig_node *orig_node;
 600         uint32_t i;
 601         int ret;
 602
 603         /* resize all orig nodes because orig_node->bcast_own(_sum) depend on
 604          * if_num */
 605         for (i = 0; i < hash->size; i++) {
 606                 head = &hash->table[i];
 607
 608                 rcu_read_lock();
 609                 hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
 610                         spin_lock_bh(&orig_node->ogm_cnt_lock);
 611                         ret = orig_node_del_if(orig_node, max_if_num,
 612                                         hard_iface->if_num);
 613                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
 614
 615                         if (ret == -1)
 616                                 goto err;
 617                 }
 618                 rcu_read_unlock();
 619         }
 620
 621         /* renumber remaining batman interfaces _inside_ of orig_hash_lock */
 622         rcu_read_lock();
 623         list_for_each_entry_rcu(hard_iface_tmp, &hardif_list, list) {
 624                 if (hard_iface_tmp->if_status == IF_NOT_IN_USE)
 625                         continue;
 626
 627                 if (hard_iface == hard_iface_tmp)
 628                         continue;
 629
 630                 if (hard_iface->soft_iface != hard_iface_tmp->soft_iface)
 631                         continue;
 632
 633                 if (hard_iface_tmp->if_num > hard_iface->if_num)
 634                         hard_iface_tmp->if_num--;
 635         }
 636         rcu_read_unlock();
 637
 638         hard_iface->if_num = -1;
 639         return 0;
 640
 641 err:
 642         rcu_read_unlock();
 643         return -ENOMEM;
 644 }