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 /* increase the reference counter for this originator */
  23
  24 #include "main.h"
  25 #include "originator.h"
  26 #include "hash.h"
  27 #include "translation-table.h"
  28 #include "routing.h"
  29 #include "gateway_client.h"
  30 #include "hard-interface.h"
  31 #include "unicast.h"
  32 #include "soft-interface.h"
  33
  34 static void purge_orig(struct work_struct *work);
  35
  36 static void start_purge_timer(struct bat_priv *bat_priv)
  37 {
  38         INIT_DELAYED_WORK(&bat_priv->orig_work, purge_orig);
  39         queue_delayed_work(bat_event_workqueue, &bat_priv->orig_work, 1 * HZ);
  40 }
  41
  42 int originator_init(struct bat_priv *bat_priv)
  43 {
  44         if (bat_priv->orig_hash)
  45                 return 1;
  46
  47         bat_priv->orig_hash = hash_new(1024);
  48
  49         if (!bat_priv->orig_hash)
  50                 goto err;
  51
  52         start_purge_timer(bat_priv);
  53         return 1;
  54
  55 err:
  56         return 0;
  57 }
  58
  59 static void neigh_node_free_rcu(struct rcu_head *rcu)
  60 {
  61         struct neigh_node *neigh_node;
  62
  63         neigh_node = container_of(rcu, struct neigh_node, rcu);
  64         kfree(neigh_node);
  65 }
  66
  67 void neigh_node_free_ref(struct neigh_node *neigh_node)
  68 {
  69         if (atomic_dec_and_test(&neigh_node->refcount))
  70                 call_rcu(&neigh_node->rcu, neigh_node_free_rcu);
  71 }
  72
  73 /* increases the refcounter of a found router */
  74 struct neigh_node *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 *create_neighbor(struct orig_node *orig_node,
  89                                    struct orig_node *orig_neigh_node,
  90                                    uint8_t *neigh,
  91                                    struct hard_iface *if_incoming)
  92 {
  93         struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
  94         struct neigh_node *neigh_node;
  95
  96         bat_dbg(DBG_BATMAN, bat_priv,
  97                 "Creating new last-hop neighbor of originator\n");
  98
  99         neigh_node = kzalloc(sizeof(struct neigh_node), GFP_ATOMIC);
 100         if (!neigh_node)
 101                 return NULL;
 102
 103         INIT_HLIST_NODE(&neigh_node->list);
 104         INIT_LIST_HEAD(&neigh_node->bonding_list);
 105         spin_lock_init(&neigh_node->tq_lock);
 106
 107         memcpy(neigh_node->addr, neigh, ETH_ALEN);
 108         neigh_node->orig_node = orig_neigh_node;
 109         neigh_node->if_incoming = if_incoming;
 110
 111         /* extra reference for return */
 112         atomic_set(&neigh_node->refcount, 2);
 113
 114         spin_lock_bh(&orig_node->neigh_list_lock);
 115         hlist_add_head_rcu(&neigh_node->list, &orig_node->neigh_list);
 116         spin_unlock_bh(&orig_node->neigh_list_lock);
 117         return neigh_node;
 118 }
 119
 120 static void orig_node_free_rcu(struct rcu_head *rcu)
 121 {
 122         struct hlist_node *node, *node_tmp;
 123         struct neigh_node *neigh_node, *tmp_neigh_node;
 124         struct orig_node *orig_node;
 125
 126         orig_node = container_of(rcu, struct orig_node, rcu);
 127
 128         spin_lock_bh(&orig_node->neigh_list_lock);
 129
 130         /* for all bonding members ... */
 131         list_for_each_entry_safe(neigh_node, tmp_neigh_node,
 132                                  &orig_node->bond_list, bonding_list) {
 133                 list_del_rcu(&neigh_node->bonding_list);
 134                 neigh_node_free_ref(neigh_node);
 135         }
 136
 137         /* for all neighbors towards this originator ... */
 138         hlist_for_each_entry_safe(neigh_node, node, node_tmp,
 139                                   &orig_node->neigh_list, list) {
 140                 hlist_del_rcu(&neigh_node->list);
 141                 neigh_node_free_ref(neigh_node);
 142         }
 143
 144         spin_unlock_bh(&orig_node->neigh_list_lock);
 145
 146         frag_list_free(&orig_node->frag_list);
 147         hna_global_del_orig(orig_node->bat_priv, orig_node,
 148                             "originator timed out");
 149
 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         int 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, 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(struct 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
 219         /* extra reference for return */
 220         atomic_set(&orig_node->refcount, 2);
 221
 222         orig_node->bat_priv = bat_priv;
 223         memcpy(orig_node->orig, addr, ETH_ALEN);
 224         orig_node->router = NULL;
 225         orig_node->hna_buff = NULL;
 226         orig_node->bcast_seqno_reset = jiffies - 1
 227                                         - msecs_to_jiffies(RESET_PROTECTION_MS);
 228         orig_node->batman_seqno_reset = jiffies - 1
 229                                         - msecs_to_jiffies(RESET_PROTECTION_MS);
 230
 231         atomic_set(&orig_node->bond_candidates, 0);
 232
 233         size = bat_priv->num_ifaces * sizeof(unsigned long) * NUM_WORDS;
 234
 235         orig_node->bcast_own = kzalloc(size, GFP_ATOMIC);
 236         if (!orig_node->bcast_own)
 237                 goto free_orig_node;
 238
 239         size = bat_priv->num_ifaces * sizeof(uint8_t);
 240         orig_node->bcast_own_sum = kzalloc(size, GFP_ATOMIC);
 241
 242         INIT_LIST_HEAD(&orig_node->frag_list);
 243         orig_node->last_frag_packet = 0;
 244
 245         if (!orig_node->bcast_own_sum)
 246                 goto free_bcast_own;
 247
 248         hash_added = hash_add(bat_priv->orig_hash, compare_orig,
 249                               choose_orig, orig_node, &orig_node->hash_entry);
 250         if (hash_added < 0)
 251                 goto free_bcast_own_sum;
 252
 253         return orig_node;
 254 free_bcast_own_sum:
 255         kfree(orig_node->bcast_own_sum);
 256 free_bcast_own:
 257         kfree(orig_node->bcast_own);
 258 free_orig_node:
 259         kfree(orig_node);
 260         return NULL;
 261 }
 262
 263 static bool purge_orig_neighbors(struct bat_priv *bat_priv,
 264                                  struct orig_node *orig_node,
 265                                  struct neigh_node **best_neigh_node)
 266 {
 267         struct hlist_node *node, *node_tmp;
 268         struct neigh_node *neigh_node;
 269         bool neigh_purged = false;
 270
 271         *best_neigh_node = NULL;
 272
 273         spin_lock_bh(&orig_node->neigh_list_lock);
 274
 275         /* for all neighbors towards this originator ... */
 276         hlist_for_each_entry_safe(neigh_node, node, node_tmp,
 277                                   &orig_node->neigh_list, list) {
 278
 279                 if ((time_after(jiffies,
 280                         neigh_node->last_valid + PURGE_TIMEOUT * HZ)) ||
 281                     (neigh_node->if_incoming->if_status == IF_INACTIVE) ||
 282                     (neigh_node->if_incoming->if_status == IF_NOT_IN_USE) ||
 283                     (neigh_node->if_incoming->if_status == IF_TO_BE_REMOVED)) {
 284
 285                         if ((neigh_node->if_incoming->if_status ==
 286                                                                 IF_INACTIVE) ||
 287                             (neigh_node->if_incoming->if_status ==
 288                                                         IF_NOT_IN_USE) ||
 289                             (neigh_node->if_incoming->if_status ==
 290                                                         IF_TO_BE_REMOVED))
 291                                 bat_dbg(DBG_BATMAN, bat_priv,
 292                                         "neighbor purge: originator %pM, "
 293                                         "neighbor: %pM, iface: %s\n",
 294                                         orig_node->orig, neigh_node->addr,
 295                                         neigh_node->if_incoming->net_dev->name);
 296                         else
 297                                 bat_dbg(DBG_BATMAN, bat_priv,
 298                                         "neighbor timeout: originator %pM, "
 299                                         "neighbor: %pM, last_valid: %lu\n",
 300                                         orig_node->orig, neigh_node->addr,
 301                                         (neigh_node->last_valid / HZ));
 302
 303                         neigh_purged = true;
 304
 305                         hlist_del_rcu(&neigh_node->list);
 306                         bonding_candidate_del(orig_node, neigh_node);
 307                         neigh_node_free_ref(neigh_node);
 308                 } else {
 309                         if ((!*best_neigh_node) ||
 310                             (neigh_node->tq_avg > (*best_neigh_node)->tq_avg))
 311                                 *best_neigh_node = neigh_node;
 312                 }
 313         }
 314
 315         spin_unlock_bh(&orig_node->neigh_list_lock);
 316         return neigh_purged;
 317 }
 318
 319 static bool purge_orig_node(struct bat_priv *bat_priv,
 320                             struct orig_node *orig_node)
 321 {
 322         struct neigh_node *best_neigh_node;
 323
 324         if (time_after(jiffies,
 325                 orig_node->last_valid + 2 * PURGE_TIMEOUT * HZ)) {
 326
 327                 bat_dbg(DBG_BATMAN, bat_priv,
 328                         "Originator timeout: originator %pM, last_valid %lu\n",
 329                         orig_node->orig, (orig_node->last_valid / HZ));
 330                 return true;
 331         } else {
 332                 if (purge_orig_neighbors(bat_priv, orig_node,
 333                                                         &best_neigh_node)) {
 334                         update_routes(bat_priv, orig_node,
 335                                       best_neigh_node,
 336                                       orig_node->hna_buff,
 337                                       orig_node->hna_buff_len);
 338                 }
 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         int 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                                         gw_node_delete(bat_priv, orig_node);
 367                                 hlist_del_rcu(node);
 368                                 orig_node_free_ref(orig_node);
 369                                 continue;
 370                         }
 371
 372                         if (time_after(jiffies, orig_node->last_frag_packet +
 373                                                 msecs_to_jiffies(FRAG_TIMEOUT)))
 374                                 frag_list_free(&orig_node->frag_list);
 375                 }
 376                 spin_unlock_bh(list_lock);
 377         }
 378
 379         gw_node_purge(bat_priv);
 380         gw_election(bat_priv);
 381
 382         softif_neigh_purge(bat_priv);
 383 }
 384
 385 static void purge_orig(struct work_struct *work)
 386 {
 387         struct delayed_work *delayed_work =
 388                 container_of(work, struct delayed_work, work);
 389         struct bat_priv *bat_priv =
 390                 container_of(delayed_work, struct bat_priv, orig_work);
 391
 392         _purge_orig(bat_priv);
 393         start_purge_timer(bat_priv);
 394 }
 395
 396 void purge_orig_ref(struct bat_priv *bat_priv)
 397 {
 398         _purge_orig(bat_priv);
 399 }
 400
 401 int orig_seq_print_text(struct seq_file *seq, void *offset)
 402 {
 403         struct net_device *net_dev = (struct net_device *)seq->private;
 404         struct bat_priv *bat_priv = netdev_priv(net_dev);
 405         struct hashtable_t *hash = bat_priv->orig_hash;
 406         struct hlist_node *node, *node_tmp;
 407         struct hlist_head *head;
 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         int i;
 414
 415         if ((!bat_priv->primary_if) ||
 416             (bat_priv->primary_if->if_status != IF_ACTIVE)) {
 417                 if (!bat_priv->primary_if)
 418                         return seq_printf(seq, "BATMAN mesh %s disabled - "
 419                                      "please specify interfaces to enable it\n",
 420                                      net_dev->name);
 421
 422                 return seq_printf(seq, "BATMAN mesh %s "
 423                                   "disabled - primary interface not active\n",
 424                                   net_dev->name);
 425         }
 426
 427         seq_printf(seq, "[B.A.T.M.A.N. adv %s%s, MainIF/MAC: %s/%pM (%s)]\n",
 428                    SOURCE_VERSION, REVISION_VERSION_STR,
 429                    bat_priv->primary_if->net_dev->name,
 430                    bat_priv->primary_if->net_dev->dev_addr, net_dev->name);
 431         seq_printf(seq, "  %-15s %s (%s/%i) %17s [%10s]: %20s ...\n",
 432                    "Originator", "last-seen", "#", TQ_MAX_VALUE, "Nexthop",
 433                    "outgoingIF", "Potential nexthops");
 434
 435         for (i = 0; i < hash->size; i++) {
 436                 head = &hash->table[i];
 437
 438                 rcu_read_lock();
 439                 hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
 440                         neigh_node = orig_node_get_router(orig_node);
 441                         if (!neigh_node)
 442                                 continue;
 443
 444                         if (neigh_node->tq_avg == 0)
 445                                 goto next;
 446
 447                         last_seen_secs = jiffies_to_msecs(jiffies -
 448                                                 orig_node->last_valid) / 1000;
 449                         last_seen_msecs = jiffies_to_msecs(jiffies -
 450                                                 orig_node->last_valid) % 1000;
 451
 452                         seq_printf(seq, "%pM %4i.%03is   (%3i) %pM [%10s]:",
 453                                    orig_node->orig, last_seen_secs,
 454                                    last_seen_msecs, neigh_node->tq_avg,
 455                                    neigh_node->addr,
 456                                    neigh_node->if_incoming->net_dev->name);
 457
 458                         hlist_for_each_entry_rcu(neigh_node_tmp, node_tmp,
 459                                                  &orig_node->neigh_list, list) {
 460                                 seq_printf(seq, " %pM (%3i)",
 461                                            neigh_node_tmp->addr,
 462                                            neigh_node_tmp->tq_avg);
 463                         }
 464
 465                         seq_printf(seq, "\n");
 466                         batman_count++;
 467
 468 next:
 469                         neigh_node_free_ref(neigh_node);
 470                 }
 471                 rcu_read_unlock();
 472         }
 473
 474         if (batman_count == 0)
 475                 seq_printf(seq, "No batman nodes in range ...\n");
 476
 477         return 0;
 478 }
 479
 480 static int orig_node_add_if(struct orig_node *orig_node, int max_if_num)
 481 {
 482         void *data_ptr;
 483
 484         data_ptr = kmalloc(max_if_num * sizeof(unsigned long) * NUM_WORDS,
 485                            GFP_ATOMIC);
 486         if (!data_ptr) {
 487                 pr_err("Can't resize orig: out of memory\n");
 488                 return -1;
 489         }
 490
 491         memcpy(data_ptr, orig_node->bcast_own,
 492                (max_if_num - 1) * sizeof(unsigned long) * NUM_WORDS);
 493         kfree(orig_node->bcast_own);
 494         orig_node->bcast_own = data_ptr;
 495
 496         data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC);
 497         if (!data_ptr) {
 498                 pr_err("Can't resize orig: out of memory\n");
 499                 return -1;
 500         }
 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         int i, ret;
 518
 519         /* resize all orig nodes because orig_node->bcast_own(_sum) depend on
 520          * if_num */
 521         for (i = 0; i < hash->size; i++) {
 522                 head = &hash->table[i];
 523
 524                 rcu_read_lock();
 525                 hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
 526                         spin_lock_bh(&orig_node->ogm_cnt_lock);
 527                         ret = orig_node_add_if(orig_node, max_if_num);
 528                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
 529
 530                         if (ret == -1)
 531                                 goto err;
 532                 }
 533                 rcu_read_unlock();
 534         }
 535
 536         return 0;
 537
 538 err:
 539         rcu_read_unlock();
 540         return -ENOMEM;
 541 }
 542
 543 static int orig_node_del_if(struct orig_node *orig_node,
 544                      int max_if_num, int del_if_num)
 545 {
 546         void *data_ptr = NULL;
 547         int chunk_size;
 548
 549         /* last interface was removed */
 550         if (max_if_num == 0)
 551                 goto free_bcast_own;
 552
 553         chunk_size = sizeof(unsigned long) * NUM_WORDS;
 554         data_ptr = kmalloc(max_if_num * chunk_size, GFP_ATOMIC);
 555         if (!data_ptr) {
 556                 pr_err("Can't resize orig: out of memory\n");
 557                 return -1;
 558         }
 559
 560         /* copy first part */
 561         memcpy(data_ptr, orig_node->bcast_own, del_if_num * chunk_size);
 562
 563         /* copy second part */
 564         memcpy(data_ptr + del_if_num * chunk_size,
 565                orig_node->bcast_own + ((del_if_num + 1) * chunk_size),
 566                (max_if_num - del_if_num) * chunk_size);
 567
 568 free_bcast_own:
 569         kfree(orig_node->bcast_own);
 570         orig_node->bcast_own = data_ptr;
 571
 572         if (max_if_num == 0)
 573                 goto free_own_sum;
 574
 575         data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC);
 576         if (!data_ptr) {
 577                 pr_err("Can't resize orig: out of memory\n");
 578                 return -1;
 579         }
 580
 581         memcpy(data_ptr, orig_node->bcast_own_sum,
 582                del_if_num * sizeof(uint8_t));
 583
 584         memcpy(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 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         int i, ret;
 604
 605         /* resize all orig nodes because orig_node->bcast_own(_sum) depend on
 606          * if_num */
 607         for (i = 0; i < hash->size; i++) {
 608                 head = &hash->table[i];
 609
 610                 rcu_read_lock();
 611                 hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
 612                         spin_lock_bh(&orig_node->ogm_cnt_lock);
 613                         ret = orig_node_del_if(orig_node, max_if_num,
 614                                         hard_iface->if_num);
 615                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
 616
 617                         if (ret == -1)
 618                                 goto err;
 619                 }
 620                 rcu_read_unlock();
 621         }
 622
 623         /* renumber remaining batman interfaces _inside_ of orig_hash_lock */
 624         rcu_read_lock();
 625         list_for_each_entry_rcu(hard_iface_tmp, &hardif_list, list) {
 626                 if (hard_iface_tmp->if_status == IF_NOT_IN_USE)
 627                         continue;
 628
 629                 if (hard_iface == hard_iface_tmp)
 630                         continue;
 631
 632                 if (hard_iface->soft_iface != hard_iface_tmp->soft_iface)
 633                         continue;
 634
 635                 if (hard_iface_tmp->if_num > hard_iface->if_num)
 636                         hard_iface_tmp->if_num--;
 637         }
 638         rcu_read_unlock();
 639
 640         hard_iface->if_num = -1;
 641         return 0;
 642
 643 err:
 644         rcu_read_unlock();
 645         return -ENOMEM;
 646 }