net/batman-adv/originator.c

   1 /*
   2  * Copyright (C) 2009-2011 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 "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
  32 static void purge_orig(struct work_struct *work);
  33
  34 static void start_purge_timer(struct bat_priv *bat_priv)
  35 {
  36         INIT_DELAYED_WORK(&bat_priv->orig_work, purge_orig);
  37         queue_delayed_work(bat_event_workqueue, &bat_priv->orig_work, 1 * HZ);
  38 }
  39
  40 /* returns 1 if they are the same originator */
  41 static int compare_orig(const struct hlist_node *node, const void *data2)
  42 {
  43         const void *data1 = container_of(node, struct orig_node, hash_entry);
  44
  45         return (memcmp(data1, data2, ETH_ALEN) == 0 ? 1 : 0);
  46 }
  47
  48 int originator_init(struct bat_priv *bat_priv)
  49 {
  50         if (bat_priv->orig_hash)
  51                 return 1;
  52
  53         bat_priv->orig_hash = hash_new(1024);
  54
  55         if (!bat_priv->orig_hash)
  56                 goto err;
  57
  58         start_purge_timer(bat_priv);
  59         return 1;
  60
  61 err:
  62         return 0;
  63 }
  64
  65 void neigh_node_free_ref(struct neigh_node *neigh_node)
  66 {
  67         if (atomic_dec_and_test(&neigh_node->refcount))
  68                 kfree_rcu(neigh_node, rcu);
  69 }
  70
  71 /* increases the refcounter of a found router */
  72 struct neigh_node *orig_node_get_router(struct orig_node *orig_node)
  73 {
  74         struct neigh_node *router;
  75
  76         rcu_read_lock();
  77         router = rcu_dereference(orig_node->router);
  78
  79         if (router && !atomic_inc_not_zero(&router->refcount))
  80                 router = NULL;
  81
  82         rcu_read_unlock();
  83         return router;
  84 }
  85
  86 struct neigh_node *create_neighbor(struct orig_node *orig_node,
  87                                    struct orig_node *orig_neigh_node,
  88                                    const uint8_t *neigh,
  89                                    struct hard_iface *if_incoming)
  90 {
  91         struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
  92         struct neigh_node *neigh_node;
  93
  94         bat_dbg(DBG_BATMAN, bat_priv,
  95                 "Creating new last-hop neighbor of originator\n");
  96
  97         neigh_node = kzalloc(sizeof(*neigh_node), GFP_ATOMIC);
  98         if (!neigh_node)
  99                 return NULL;
 100
 101         INIT_HLIST_NODE(&neigh_node->list);
 102         INIT_LIST_HEAD(&neigh_node->bonding_list);
 103         spin_lock_init(&neigh_node->tq_lock);
 104
 105         memcpy(neigh_node->addr, neigh, ETH_ALEN);
 106         neigh_node->orig_node = orig_neigh_node;
 107         neigh_node->if_incoming = if_incoming;
 108
 109         /* extra reference for return */
 110         atomic_set(&neigh_node->refcount, 2);
 111
 112         spin_lock_bh(&orig_node->neigh_list_lock);
 113         hlist_add_head_rcu(&neigh_node->list, &orig_node->neigh_list);
 114         spin_unlock_bh(&orig_node->neigh_list_lock);
 115         return neigh_node;
 116 }
 117
 118 static void orig_node_free_rcu(struct rcu_head *rcu)
 119 {
 120         struct hlist_node *node, *node_tmp;
 121         struct neigh_node *neigh_node, *tmp_neigh_node;
 122         struct orig_node *orig_node;
 123
 124         orig_node = container_of(rcu, struct orig_node, rcu);
 125
 126         spin_lock_bh(&orig_node->neigh_list_lock);
 127
 128         /* for all bonding members ... */
 129         list_for_each_entry_safe(neigh_node, tmp_neigh_node,
 130                                  &orig_node->bond_list, bonding_list) {
 131                 list_del_rcu(&neigh_node->bonding_list);
 132                 neigh_node_free_ref(neigh_node);
 133         }
 134
 135         /* for all neighbors towards this originator ... */
 136         hlist_for_each_entry_safe(neigh_node, node, node_tmp,
 137                                   &orig_node->neigh_list, list) {
 138                 hlist_del_rcu(&neigh_node->list);
 139                 neigh_node_free_ref(neigh_node);
 140         }
 141
 142         spin_unlock_bh(&orig_node->neigh_list_lock);
 143
 144         frag_list_free(&orig_node->frag_list);
 145         tt_global_del_orig(orig_node->bat_priv, orig_node,
 146                             "originator timed out");
 147
 148         kfree(orig_node->tt_buff);
 149         kfree(orig_node->bcast_own);
 150         kfree(orig_node->bcast_own_sum);
 151         kfree(orig_node);
 152 }
 153
 154 void orig_node_free_ref(struct orig_node *orig_node)
 155 {
 156         if (atomic_dec_and_test(&orig_node->refcount))
 157                 call_rcu(&orig_node->rcu, orig_node_free_rcu);
 158 }
 159
 160 void originator_free(struct bat_priv *bat_priv)
 161 {
 162         struct hashtable_t *hash = bat_priv->orig_hash;
 163         struct hlist_node *node, *node_tmp;
 164         struct hlist_head *head;
 165         spinlock_t *list_lock; /* spinlock to protect write access */
 166         struct orig_node *orig_node;
 167         int i;
 168
 169         if (!hash)
 170                 return;
 171
 172         cancel_delayed_work_sync(&bat_priv->orig_work);
 173
 174         bat_priv->orig_hash = NULL;
 175
 176         for (i = 0; i < hash->size; i++) {
 177                 head = &hash->table[i];
 178                 list_lock = &hash->list_locks[i];
 179
 180                 spin_lock_bh(list_lock);
 181                 hlist_for_each_entry_safe(orig_node, node, node_tmp,
 182                                           head, hash_entry) {
 183
 184                         hlist_del_rcu(node);
 185                         orig_node_free_ref(orig_node);
 186                 }
 187                 spin_unlock_bh(list_lock);
 188         }
 189
 190         hash_destroy(hash);
 191 }
 192
 193 /* this function finds or creates an originator entry for the given
 194  * address if it does not exits */
 195 struct orig_node *get_orig_node(struct bat_priv *bat_priv, const uint8_t *addr)
 196 {
 197         struct orig_node *orig_node;
 198         int size;
 199         int hash_added;
 200
 201         orig_node = orig_hash_find(bat_priv, addr);
 202         if (orig_node)
 203                 return orig_node;
 204
 205         bat_dbg(DBG_BATMAN, bat_priv,
 206                 "Creating new originator: %pM\n", addr);
 207
 208         orig_node = kzalloc(sizeof(*orig_node), GFP_ATOMIC);
 209         if (!orig_node)
 210                 return NULL;
 211
 212         INIT_HLIST_HEAD(&orig_node->neigh_list);
 213         INIT_LIST_HEAD(&orig_node->bond_list);
 214         spin_lock_init(&orig_node->ogm_cnt_lock);
 215         spin_lock_init(&orig_node->bcast_seqno_lock);
 216         spin_lock_init(&orig_node->neigh_list_lock);
 217         spin_lock_init(&orig_node->tt_buff_lock);
 218
 219         /* extra reference for return */
 220         atomic_set(&orig_node->refcount, 2);
 221
 222         orig_node->tt_poss_change = false;
 223         orig_node->bat_priv = bat_priv;
 224         memcpy(orig_node->orig, addr, ETH_ALEN);
 225         orig_node->router = NULL;
 226         orig_node->tt_crc = 0;
 227         atomic_set(&orig_node->last_ttvn, 0);
 228         orig_node->tt_buff = NULL;
 229         orig_node->tt_buff_len = 0;
 230         atomic_set(&orig_node->tt_size, 0);
 231         orig_node->bcast_seqno_reset = jiffies - 1
 232                                         - msecs_to_jiffies(RESET_PROTECTION_MS);
 233         orig_node->batman_seqno_reset = jiffies - 1
 234                                         - msecs_to_jiffies(RESET_PROTECTION_MS);
 235
 236         atomic_set(&orig_node->bond_candidates, 0);
 237
 238         size = bat_priv->num_ifaces * sizeof(unsigned long) * NUM_WORDS;
 239
 240         orig_node->bcast_own = kzalloc(size, GFP_ATOMIC);
 241         if (!orig_node->bcast_own)
 242                 goto free_orig_node;
 243
 244         size = bat_priv->num_ifaces * sizeof(uint8_t);
 245         orig_node->bcast_own_sum = kzalloc(size, GFP_ATOMIC);
 246
 247         INIT_LIST_HEAD(&orig_node->frag_list);
 248         orig_node->last_frag_packet = 0;
 249
 250         if (!orig_node->bcast_own_sum)
 251                 goto free_bcast_own;
 252
 253         hash_added = hash_add(bat_priv->orig_hash, compare_orig,
 254                               choose_orig, orig_node, &orig_node->hash_entry);
 255         if (hash_added != 0)
 256                 goto free_bcast_own_sum;
 257
 258         return orig_node;
 259 free_bcast_own_sum:
 260         kfree(orig_node->bcast_own_sum);
 261 free_bcast_own:
 262         kfree(orig_node->bcast_own);
 263 free_orig_node:
 264         kfree(orig_node);
 265         return NULL;
 266 }
 267
 268 static bool purge_orig_neighbors(struct bat_priv *bat_priv,
 269                                  struct orig_node *orig_node,
 270                                  struct neigh_node **best_neigh_node)
 271 {
 272         struct hlist_node *node, *node_tmp;
 273         struct neigh_node *neigh_node;
 274         bool neigh_purged = false;
 275
 276         *best_neigh_node = NULL;
 277
 278         spin_lock_bh(&orig_node->neigh_list_lock);
 279
 280         /* for all neighbors towards this originator ... */
 281         hlist_for_each_entry_safe(neigh_node, node, node_tmp,
 282                                   &orig_node->neigh_list, list) {
 283
 284                 if ((time_after(jiffies,
 285                         neigh_node->last_valid + PURGE_TIMEOUT * HZ)) ||
 286                     (neigh_node->if_incoming->if_status == IF_INACTIVE) ||
 287                     (neigh_node->if_incoming->if_status == IF_NOT_IN_USE) ||
 288                     (neigh_node->if_incoming->if_status == IF_TO_BE_REMOVED)) {
 289
 290                         if ((neigh_node->if_incoming->if_status ==
 291                                                                 IF_INACTIVE) ||
 292                             (neigh_node->if_incoming->if_status ==
 293                                                         IF_NOT_IN_USE) ||
 294                             (neigh_node->if_incoming->if_status ==
 295                                                         IF_TO_BE_REMOVED))
 296                                 bat_dbg(DBG_BATMAN, bat_priv,
 297                                         "neighbor purge: originator %pM, "
 298                                         "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, "
 304                                         "neighbor: %pM, last_valid: %lu\n",
 305                                         orig_node->orig, neigh_node->addr,
 306                                         (neigh_node->last_valid / HZ));
 307
 308                         neigh_purged = true;
 309
 310                         hlist_del_rcu(&neigh_node->list);
 311                         bonding_candidate_del(orig_node, neigh_node);
 312                         neigh_node_free_ref(neigh_node);
 313                 } else {
 314                         if ((!*best_neigh_node) ||
 315                             (neigh_node->tq_avg > (*best_neigh_node)->tq_avg))
 316                                 *best_neigh_node = neigh_node;
 317                 }
 318         }
 319
 320         spin_unlock_bh(&orig_node->neigh_list_lock);
 321         return neigh_purged;
 322 }
 323
 324 static bool purge_orig_node(struct bat_priv *bat_priv,
 325                             struct orig_node *orig_node)
 326 {
 327         struct neigh_node *best_neigh_node;
 328
 329         if (time_after(jiffies,
 330                 orig_node->last_valid + 2 * PURGE_TIMEOUT * HZ)) {
 331
 332                 bat_dbg(DBG_BATMAN, bat_priv,
 333                         "Originator timeout: originator %pM, last_valid %lu\n",
 334                         orig_node->orig, (orig_node->last_valid / HZ));
 335                 return true;
 336         } else {
 337                 if (purge_orig_neighbors(bat_priv, orig_node,
 338                                                         &best_neigh_node)) {
 339                         update_route(bat_priv, orig_node, best_neigh_node);
 340                 }
 341         }
 342
 343         return false;
 344 }
 345
 346 static void _purge_orig(struct bat_priv *bat_priv)
 347 {
 348         struct hashtable_t *hash = bat_priv->orig_hash;
 349         struct hlist_node *node, *node_tmp;
 350         struct hlist_head *head;
 351         spinlock_t *list_lock; /* spinlock to protect write access */
 352         struct orig_node *orig_node;
 353         int i;
 354
 355         if (!hash)
 356                 return;
 357
 358         /* for all origins... */
 359         for (i = 0; i < hash->size; i++) {
 360                 head = &hash->table[i];
 361                 list_lock = &hash->list_locks[i];
 362
 363                 spin_lock_bh(list_lock);
 364                 hlist_for_each_entry_safe(orig_node, node, node_tmp,
 365                                           head, hash_entry) {
 366                         if (purge_orig_node(bat_priv, orig_node)) {
 367                                 if (orig_node->gw_flags)
 368                                         gw_node_delete(bat_priv, orig_node);
 369                                 hlist_del_rcu(node);
 370                                 orig_node_free_ref(orig_node);
 371                                 continue;
 372                         }
 373
 374                         if (time_after(jiffies, orig_node->last_frag_packet +
 375                                                 msecs_to_jiffies(FRAG_TIMEOUT)))
 376                                 frag_list_free(&orig_node->frag_list);
 377                 }
 378                 spin_unlock_bh(list_lock);
 379         }
 380
 381         gw_node_purge(bat_priv);
 382         gw_election(bat_priv);
 383
 384         softif_neigh_purge(bat_priv);
 385 }
 386
 387 static void purge_orig(struct work_struct *work)
 388 {
 389         struct delayed_work *delayed_work =
 390                 container_of(work, struct delayed_work, work);
 391         struct bat_priv *bat_priv =
 392                 container_of(delayed_work, struct bat_priv, orig_work);
 393
 394         _purge_orig(bat_priv);
 395         start_purge_timer(bat_priv);
 396 }
 397
 398 void purge_orig_ref(struct bat_priv *bat_priv)
 399 {
 400         _purge_orig(bat_priv);
 401 }
 402
 403 int orig_seq_print_text(struct seq_file *seq, void *offset)
 404 {
 405         struct net_device *net_dev = (struct net_device *)seq->private;
 406         struct bat_priv *bat_priv = netdev_priv(net_dev);
 407         struct hashtable_t *hash = bat_priv->orig_hash;
 408         struct hlist_node *node, *node_tmp;
 409         struct hlist_head *head;
 410         struct hard_iface *primary_if;
 411         struct orig_node *orig_node;
 412         struct neigh_node *neigh_node, *neigh_node_tmp;
 413         int batman_count = 0;
 414         int last_seen_secs;
 415         int last_seen_msecs;
 416         int i, ret = 0;
 417
 418         primary_if = primary_if_get_selected(bat_priv);
 419
 420         if (!primary_if) {
 421                 ret = seq_printf(seq, "BATMAN mesh %s disabled - "
 422                                  "please specify interfaces to enable it\n",
 423                                  net_dev->name);
 424                 goto out;
 425         }
 426
 427         if (primary_if->if_status != IF_ACTIVE) {
 428                 ret = seq_printf(seq, "BATMAN mesh %s "
 429                                  "disabled - primary interface not active\n",
 430                                  net_dev->name);
 431                 goto out;
 432         }
 433
 434         seq_printf(seq, "[B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
 435                    SOURCE_VERSION, primary_if->net_dev->name,
 436                    primary_if->net_dev->dev_addr, net_dev->name);
 437         seq_printf(seq, "  %-15s %s (%s/%i) %17s [%10s]: %20s ...\n",
 438                    "Originator", "last-seen", "#", TQ_MAX_VALUE, "Nexthop",
 439                    "outgoingIF", "Potential nexthops");
 440
 441         for (i = 0; i < hash->size; i++) {
 442                 head = &hash->table[i];
 443
 444                 rcu_read_lock();
 445                 hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
 446                         neigh_node = orig_node_get_router(orig_node);
 447                         if (!neigh_node)
 448                                 continue;
 449
 450                         if (neigh_node->tq_avg == 0)
 451                                 goto next;
 452
 453                         last_seen_secs = jiffies_to_msecs(jiffies -
 454                                                 orig_node->last_valid) / 1000;
 455                         last_seen_msecs = jiffies_to_msecs(jiffies -
 456                                                 orig_node->last_valid) % 1000;
 457
 458                         seq_printf(seq, "%pM %4i.%03is   (%3i) %pM [%10s]:",
 459                                    orig_node->orig, last_seen_secs,
 460                                    last_seen_msecs, neigh_node->tq_avg,
 461                                    neigh_node->addr,
 462                                    neigh_node->if_incoming->net_dev->name);
 463
 464                         hlist_for_each_entry_rcu(neigh_node_tmp, node_tmp,
 465                                                  &orig_node->neigh_list, list) {
 466                                 seq_printf(seq, " %pM (%3i)",
 467                                            neigh_node_tmp->addr,
 468                                            neigh_node_tmp->tq_avg);
 469                         }
 470
 471                         seq_printf(seq, "\n");
 472                         batman_count++;
 473
 474 next:
 475                         neigh_node_free_ref(neigh_node);
 476                 }
 477                 rcu_read_unlock();
 478         }
 479
 480         if (batman_count == 0)
 481                 seq_printf(seq, "No batman nodes in range ...\n");
 482
 483 out:
 484         if (primary_if)
 485                 hardif_free_ref(primary_if);
 486         return ret;
 487 }
 488
 489 static int orig_node_add_if(struct orig_node *orig_node, int max_if_num)
 490 {
 491         void *data_ptr;
 492
 493         data_ptr = kmalloc(max_if_num * sizeof(unsigned long) * NUM_WORDS,
 494                            GFP_ATOMIC);
 495         if (!data_ptr)
 496                 return -1;
 497
 498         memcpy(data_ptr, orig_node->bcast_own,
 499                (max_if_num - 1) * sizeof(unsigned long) * NUM_WORDS);
 500         kfree(orig_node->bcast_own);
 501         orig_node->bcast_own = data_ptr;
 502
 503         data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC);
 504         if (!data_ptr)
 505                 return -1;
 506
 507         memcpy(data_ptr, orig_node->bcast_own_sum,
 508                (max_if_num - 1) * sizeof(uint8_t));
 509         kfree(orig_node->bcast_own_sum);
 510         orig_node->bcast_own_sum = data_ptr;
 511
 512         return 0;
 513 }
 514
 515 int orig_hash_add_if(struct hard_iface *hard_iface, int max_if_num)
 516 {
 517         struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 518         struct hashtable_t *hash = bat_priv->orig_hash;
 519         struct hlist_node *node;
 520         struct hlist_head *head;
 521         struct orig_node *orig_node;
 522         int i, ret;
 523
 524         /* resize all orig nodes because orig_node->bcast_own(_sum) depend on
 525          * if_num */
 526         for (i = 0; i < hash->size; i++) {
 527                 head = &hash->table[i];
 528
 529                 rcu_read_lock();
 530                 hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
 531                         spin_lock_bh(&orig_node->ogm_cnt_lock);
 532                         ret = orig_node_add_if(orig_node, max_if_num);
 533                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
 534
 535                         if (ret == -1)
 536                                 goto err;
 537                 }
 538                 rcu_read_unlock();
 539         }
 540
 541         return 0;
 542
 543 err:
 544         rcu_read_unlock();
 545         return -ENOMEM;
 546 }
 547
 548 static int orig_node_del_if(struct orig_node *orig_node,
 549                      int max_if_num, int del_if_num)
 550 {
 551         void *data_ptr = NULL;
 552         int chunk_size;
 553
 554         /* last interface was removed */
 555         if (max_if_num == 0)
 556                 goto free_bcast_own;
 557
 558         chunk_size = sizeof(unsigned long) * NUM_WORDS;
 559         data_ptr = kmalloc(max_if_num * chunk_size, GFP_ATOMIC);
 560         if (!data_ptr)
 561                 return -1;
 562
 563         /* copy first part */
 564         memcpy(data_ptr, orig_node->bcast_own, del_if_num * chunk_size);
 565
 566         /* copy second part */
 567         memcpy((char *)data_ptr + del_if_num * chunk_size,
 568                orig_node->bcast_own + ((del_if_num + 1) * chunk_size),
 569                (max_if_num - del_if_num) * chunk_size);
 570
 571 free_bcast_own:
 572         kfree(orig_node->bcast_own);
 573         orig_node->bcast_own = data_ptr;
 574
 575         if (max_if_num == 0)
 576                 goto free_own_sum;
 577
 578         data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC);
 579         if (!data_ptr)
 580                 return -1;
 581
 582         memcpy(data_ptr, orig_node->bcast_own_sum,
 583                del_if_num * sizeof(uint8_t));
 584
 585         memcpy((char *)data_ptr + del_if_num * sizeof(uint8_t),
 586                orig_node->bcast_own_sum + ((del_if_num + 1) * sizeof(uint8_t)),
 587                (max_if_num - del_if_num) * sizeof(uint8_t));
 588
 589 free_own_sum:
 590         kfree(orig_node->bcast_own_sum);
 591         orig_node->bcast_own_sum = data_ptr;
 592
 593         return 0;
 594 }
 595
 596 int orig_hash_del_if(struct hard_iface *hard_iface, int max_if_num)
 597 {
 598         struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 599         struct hashtable_t *hash = bat_priv->orig_hash;
 600         struct hlist_node *node;
 601         struct hlist_head *head;
 602         struct hard_iface *hard_iface_tmp;
 603         struct orig_node *orig_node;
 604         int i, ret;
 605
 606         /* resize all orig nodes because orig_node->bcast_own(_sum) depend on
 607          * if_num */
 608         for (i = 0; i < hash->size; i++) {
 609                 head = &hash->table[i];
 610
 611                 rcu_read_lock();
 612                 hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
 613                         spin_lock_bh(&orig_node->ogm_cnt_lock);
 614                         ret = orig_node_del_if(orig_node, max_if_num,
 615                                         hard_iface->if_num);
 616                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
 617
 618                         if (ret == -1)
 619                                 goto err;
 620                 }
 621                 rcu_read_unlock();
 622         }
 623
 624         /* renumber remaining batman interfaces _inside_ of orig_hash_lock */
 625         rcu_read_lock();
 626         list_for_each_entry_rcu(hard_iface_tmp, &hardif_list, list) {
 627                 if (hard_iface_tmp->if_status == IF_NOT_IN_USE)
 628                         continue;
 629
 630                 if (hard_iface == hard_iface_tmp)
 631                         continue;
 632
 633                 if (hard_iface->soft_iface != hard_iface_tmp->soft_iface)
 634                         continue;
 635
 636                 if (hard_iface_tmp->if_num > hard_iface->if_num)
 637                         hard_iface_tmp->if_num--;
 638         }
 639         rcu_read_unlock();
 640
 641         hard_iface->if_num = -1;
 642         return 0;
 643
 644 err:
 645         rcu_read_unlock();
 646         return -ENOMEM;
 647 }