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