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 originator_init(struct bat_priv *bat_priv)
  51 {
  52         if (bat_priv->orig_hash)
  53                 return 1;
  54
  55         bat_priv->orig_hash = hash_new(1024);
  56
  57         if (!bat_priv->orig_hash)
  58                 goto err;
  59
  60         start_purge_timer(bat_priv);
  61         return 1;
  62
  63 err:
  64         return 0;
  65 }
  66
  67 void 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 *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
 103         /* extra reference for return */
 104         atomic_set(&neigh_node->refcount, 2);
 105
 106         bat_dbg(DBG_BATMAN, bat_priv,
 107                 "Creating new neighbor %pM, initial seqno %d\n",
 108                 neigh_addr, seqno);
 109
 110 out:
 111         return neigh_node;
 112 }
 113
 114 static void orig_node_free_rcu(struct rcu_head *rcu)
 115 {
 116         struct hlist_node *node, *node_tmp;
 117         struct neigh_node *neigh_node, *tmp_neigh_node;
 118         struct orig_node *orig_node;
 119
 120         orig_node = container_of(rcu, struct orig_node, rcu);
 121
 122         spin_lock_bh(&orig_node->neigh_list_lock);
 123
 124         /* for all bonding members ... */
 125         list_for_each_entry_safe(neigh_node, tmp_neigh_node,
 126                                  &orig_node->bond_list, bonding_list) {
 127                 list_del_rcu(&neigh_node->bonding_list);
 128                 neigh_node_free_ref(neigh_node);
 129         }
 130
 131         /* for all neighbors towards this originator ... */
 132         hlist_for_each_entry_safe(neigh_node, node, node_tmp,
 133                                   &orig_node->neigh_list, list) {
 134                 hlist_del_rcu(&neigh_node->list);
 135                 neigh_node_free_ref(neigh_node);
 136         }
 137
 138         spin_unlock_bh(&orig_node->neigh_list_lock);
 139
 140         frag_list_free(&orig_node->frag_list);
 141         tt_global_del_orig(orig_node->bat_priv, orig_node,
 142                            "originator timed out");
 143
 144         kfree(orig_node->tt_buff);
 145         kfree(orig_node->bcast_own);
 146         kfree(orig_node->bcast_own_sum);
 147         kfree(orig_node);
 148 }
 149
 150 void orig_node_free_ref(struct orig_node *orig_node)
 151 {
 152         if (atomic_dec_and_test(&orig_node->refcount))
 153                 call_rcu(&orig_node->rcu, orig_node_free_rcu);
 154 }
 155
 156 void originator_free(struct bat_priv *bat_priv)
 157 {
 158         struct hashtable_t *hash = bat_priv->orig_hash;
 159         struct hlist_node *node, *node_tmp;
 160         struct hlist_head *head;
 161         spinlock_t *list_lock; /* spinlock to protect write access */
 162         struct orig_node *orig_node;
 163         uint32_t i;
 164
 165         if (!hash)
 166                 return;
 167
 168         cancel_delayed_work_sync(&bat_priv->orig_work);
 169
 170         bat_priv->orig_hash = NULL;
 171
 172         for (i = 0; i < hash->size; i++) {
 173                 head = &hash->table[i];
 174                 list_lock = &hash->list_locks[i];
 175
 176                 spin_lock_bh(list_lock);
 177                 hlist_for_each_entry_safe(orig_node, node, node_tmp,
 178                                           head, hash_entry) {
 179
 180                         hlist_del_rcu(node);
 181                         orig_node_free_ref(orig_node);
 182                 }
 183                 spin_unlock_bh(list_lock);
 184         }
 185
 186         hash_destroy(hash);
 187 }
 188
 189 /* this function finds or creates an originator entry for the given
 190  * address if it does not exits */
 191 struct orig_node *get_orig_node(struct bat_priv *bat_priv, const uint8_t *addr)
 192 {
 193         struct orig_node *orig_node;
 194         int size;
 195         int hash_added;
 196
 197         orig_node = orig_hash_find(bat_priv, addr);
 198         if (orig_node)
 199                 return orig_node;
 200
 201         bat_dbg(DBG_BATMAN, bat_priv,
 202                 "Creating new originator: %pM\n", addr);
 203
 204         orig_node = kzalloc(sizeof(*orig_node), GFP_ATOMIC);
 205         if (!orig_node)
 206                 return NULL;
 207
 208         INIT_HLIST_HEAD(&orig_node->neigh_list);
 209         INIT_LIST_HEAD(&orig_node->bond_list);
 210         spin_lock_init(&orig_node->ogm_cnt_lock);
 211         spin_lock_init(&orig_node->bcast_seqno_lock);
 212         spin_lock_init(&orig_node->neigh_list_lock);
 213         spin_lock_init(&orig_node->tt_buff_lock);
 214
 215         /* extra reference for return */
 216         atomic_set(&orig_node->refcount, 2);
 217
 218         orig_node->tt_initialised = false;
 219         orig_node->tt_poss_change = false;
 220         orig_node->bat_priv = bat_priv;
 221         memcpy(orig_node->orig, addr, ETH_ALEN);
 222         orig_node->router = NULL;
 223         orig_node->tt_crc = 0;
 224         atomic_set(&orig_node->last_ttvn, 0);
 225         orig_node->tt_buff = NULL;
 226         orig_node->tt_buff_len = 0;
 227         atomic_set(&orig_node->tt_size, 0);
 228         orig_node->bcast_seqno_reset = jiffies - 1
 229                                         - msecs_to_jiffies(RESET_PROTECTION_MS);
 230         orig_node->batman_seqno_reset = jiffies - 1
 231                                         - msecs_to_jiffies(RESET_PROTECTION_MS);
 232
 233         atomic_set(&orig_node->bond_candidates, 0);
 234
 235         size = bat_priv->num_ifaces * sizeof(unsigned long) * NUM_WORDS;
 236
 237         orig_node->bcast_own = kzalloc(size, GFP_ATOMIC);
 238         if (!orig_node->bcast_own)
 239                 goto free_orig_node;
 240
 241         size = bat_priv->num_ifaces * sizeof(uint8_t);
 242         orig_node->bcast_own_sum = kzalloc(size, GFP_ATOMIC);
 243
 244         INIT_LIST_HEAD(&orig_node->frag_list);
 245         orig_node->last_frag_packet = 0;
 246
 247         if (!orig_node->bcast_own_sum)
 248                 goto free_bcast_own;
 249
 250         hash_added = hash_add(bat_priv->orig_hash, compare_orig,
 251                               choose_orig, orig_node, &orig_node->hash_entry);
 252         if (hash_added != 0)
 253                 goto free_bcast_own_sum;
 254
 255         return orig_node;
 256 free_bcast_own_sum:
 257         kfree(orig_node->bcast_own_sum);
 258 free_bcast_own:
 259         kfree(orig_node->bcast_own);
 260 free_orig_node:
 261         kfree(orig_node);
 262         return NULL;
 263 }
 264
 265 static bool purge_orig_neighbors(struct bat_priv *bat_priv,
 266                                  struct orig_node *orig_node,
 267                                  struct neigh_node **best_neigh_node)
 268 {
 269         struct hlist_node *node, *node_tmp;
 270         struct neigh_node *neigh_node;
 271         bool neigh_purged = false;
 272         unsigned long last_seen;
 273
 274         *best_neigh_node = NULL;
 275
 276         spin_lock_bh(&orig_node->neigh_list_lock);
 277
 278         /* for all neighbors towards this originator ... */
 279         hlist_for_each_entry_safe(neigh_node, node, node_tmp,
 280                                   &orig_node->neigh_list, list) {
 281
 282                 if ((has_timed_out(neigh_node->last_seen, PURGE_TIMEOUT)) ||
 283                     (neigh_node->if_incoming->if_status == IF_INACTIVE) ||
 284                     (neigh_node->if_incoming->if_status == IF_NOT_IN_USE) ||
 285                     (neigh_node->if_incoming->if_status == IF_TO_BE_REMOVED)) {
 286
 287                         last_seen = neigh_node->last_seen;
 288
 289                         if ((neigh_node->if_incoming->if_status ==
 290                                                                 IF_INACTIVE) ||
 291                             (neigh_node->if_incoming->if_status ==
 292                                                         IF_NOT_IN_USE) ||
 293                             (neigh_node->if_incoming->if_status ==
 294                                                         IF_TO_BE_REMOVED))
 295                                 bat_dbg(DBG_BATMAN, bat_priv,
 296                                         "neighbor purge: originator %pM, neighbor: %pM, iface: %s\n",
 297                                         orig_node->orig, neigh_node->addr,
 298                                         neigh_node->if_incoming->net_dev->name);
 299                         else
 300                                 bat_dbg(DBG_BATMAN, bat_priv,
 301                                         "neighbor timeout: originator %pM, neighbor: %pM, last_seen: %u\n",
 302                                         orig_node->orig, neigh_node->addr,
 303                                         jiffies_to_msecs(last_seen));
 304
 305                         neigh_purged = true;
 306
 307                         hlist_del_rcu(&neigh_node->list);
 308                         bonding_candidate_del(orig_node, neigh_node);
 309                         neigh_node_free_ref(neigh_node);
 310                 } else {
 311                         if ((!*best_neigh_node) ||
 312                             (neigh_node->tq_avg > (*best_neigh_node)->tq_avg))
 313                                 *best_neigh_node = neigh_node;
 314                 }
 315         }
 316
 317         spin_unlock_bh(&orig_node->neigh_list_lock);
 318         return neigh_purged;
 319 }
 320
 321 static bool purge_orig_node(struct bat_priv *bat_priv,
 322                             struct orig_node *orig_node)
 323 {
 324         struct neigh_node *best_neigh_node;
 325
 326         if (has_timed_out(orig_node->last_seen, 2 * PURGE_TIMEOUT)) {
 327                 bat_dbg(DBG_BATMAN, bat_priv,
 328                         "Originator timeout: originator %pM, last_seen %u\n",
 329                         orig_node->orig,
 330                         jiffies_to_msecs(orig_node->last_seen));
 331                 return true;
 332         } else {
 333                 if (purge_orig_neighbors(bat_priv, orig_node,
 334                                          &best_neigh_node))
 335                         update_route(bat_priv, orig_node, best_neigh_node);
 336         }
 337
 338         return false;
 339 }
 340
 341 static void _purge_orig(struct bat_priv *bat_priv)
 342 {
 343         struct hashtable_t *hash = bat_priv->orig_hash;
 344         struct hlist_node *node, *node_tmp;
 345         struct hlist_head *head;
 346         spinlock_t *list_lock; /* spinlock to protect write access */
 347         struct orig_node *orig_node;
 348         uint32_t i;
 349
 350         if (!hash)
 351                 return;
 352
 353         /* for all origins... */
 354         for (i = 0; i < hash->size; i++) {
 355                 head = &hash->table[i];
 356                 list_lock = &hash->list_locks[i];
 357
 358                 spin_lock_bh(list_lock);
 359                 hlist_for_each_entry_safe(orig_node, node, node_tmp,
 360                                           head, hash_entry) {
 361                         if (purge_orig_node(bat_priv, orig_node)) {
 362                                 if (orig_node->gw_flags)
 363                                         gw_node_delete(bat_priv, orig_node);
 364                                 hlist_del_rcu(node);
 365                                 orig_node_free_ref(orig_node);
 366                                 continue;
 367                         }
 368
 369                         if (has_timed_out(orig_node->last_frag_packet,
 370                                           FRAG_TIMEOUT))
 371                                 frag_list_free(&orig_node->frag_list);
 372                 }
 373                 spin_unlock_bh(list_lock);
 374         }
 375
 376         gw_node_purge(bat_priv);
 377         gw_election(bat_priv);
 378 }
 379
 380 static void purge_orig(struct work_struct *work)
 381 {
 382         struct delayed_work *delayed_work =
 383                 container_of(work, struct delayed_work, work);
 384         struct bat_priv *bat_priv =
 385                 container_of(delayed_work, struct bat_priv, orig_work);
 386
 387         _purge_orig(bat_priv);
 388         start_purge_timer(bat_priv);
 389 }
 390
 391 void purge_orig_ref(struct bat_priv *bat_priv)
 392 {
 393         _purge_orig(bat_priv);
 394 }
 395
 396 int orig_seq_print_text(struct seq_file *seq, void *offset)
 397 {
 398         struct net_device *net_dev = (struct net_device *)seq->private;
 399         struct bat_priv *bat_priv = netdev_priv(net_dev);
 400         struct hashtable_t *hash = bat_priv->orig_hash;
 401         struct hlist_node *node, *node_tmp;
 402         struct hlist_head *head;
 403         struct hard_iface *primary_if;
 404         struct orig_node *orig_node;
 405         struct neigh_node *neigh_node, *neigh_node_tmp;
 406         int batman_count = 0;
 407         int last_seen_secs;
 408         int last_seen_msecs;
 409         uint32_t i;
 410         int ret = 0;
 411
 412         primary_if = primary_if_get_selected(bat_priv);
 413
 414         if (!primary_if) {
 415                 ret = seq_printf(seq,
 416                                  "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
 417                                  net_dev->name);
 418                 goto out;
 419         }
 420
 421         if (primary_if->if_status != IF_ACTIVE) {
 422                 ret = seq_printf(seq,
 423                                  "BATMAN mesh %s disabled - primary interface not active\n",
 424                                  net_dev->name);
 425                 goto out;
 426         }
 427
 428         seq_printf(seq, "[B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
 429                    SOURCE_VERSION, primary_if->net_dev->name,
 430                    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_seen) / 1000;
 449                         last_seen_msecs = jiffies_to_msecs(jiffies -
 450                                                 orig_node->last_seen) % 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 out:
 478         if (primary_if)
 479                 hardif_free_ref(primary_if);
 480         return ret;
 481 }
 482
 483 static int orig_node_add_if(struct orig_node *orig_node, int max_if_num)
 484 {
 485         void *data_ptr;
 486
 487         data_ptr = kmalloc(max_if_num * sizeof(unsigned long) * NUM_WORDS,
 488                            GFP_ATOMIC);
 489         if (!data_ptr)
 490                 return -1;
 491
 492         memcpy(data_ptr, orig_node->bcast_own,
 493                (max_if_num - 1) * sizeof(unsigned long) * NUM_WORDS);
 494         kfree(orig_node->bcast_own);
 495         orig_node->bcast_own = data_ptr;
 496
 497         data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC);
 498         if (!data_ptr)
 499                 return -1;
 500
 501         memcpy(data_ptr, orig_node->bcast_own_sum,
 502                (max_if_num - 1) * sizeof(uint8_t));
 503         kfree(orig_node->bcast_own_sum);
 504         orig_node->bcast_own_sum = data_ptr;
 505
 506         return 0;
 507 }
 508
 509 int orig_hash_add_if(struct hard_iface *hard_iface, int max_if_num)
 510 {
 511         struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 512         struct hashtable_t *hash = bat_priv->orig_hash;
 513         struct hlist_node *node;
 514         struct hlist_head *head;
 515         struct orig_node *orig_node;
 516         uint32_t i;
 517         int 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                 return -1;
 557
 558         /* copy first part */
 559         memcpy(data_ptr, orig_node->bcast_own, del_if_num * chunk_size);
 560
 561         /* copy second part */
 562         memcpy((char *)data_ptr + del_if_num * chunk_size,
 563                orig_node->bcast_own + ((del_if_num + 1) * chunk_size),
 564                (max_if_num - del_if_num) * chunk_size);
 565
 566 free_bcast_own:
 567         kfree(orig_node->bcast_own);
 568         orig_node->bcast_own = data_ptr;
 569
 570         if (max_if_num == 0)
 571                 goto free_own_sum;
 572
 573         data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC);
 574         if (!data_ptr)
 575                 return -1;
 576
 577         memcpy(data_ptr, orig_node->bcast_own_sum,
 578                del_if_num * sizeof(uint8_t));
 579
 580         memcpy((char *)data_ptr + del_if_num * sizeof(uint8_t),
 581                orig_node->bcast_own_sum + ((del_if_num + 1) * sizeof(uint8_t)),
 582                (max_if_num - del_if_num) * sizeof(uint8_t));
 583
 584 free_own_sum:
 585         kfree(orig_node->bcast_own_sum);
 586         orig_node->bcast_own_sum = data_ptr;
 587
 588         return 0;
 589 }
 590
 591 int orig_hash_del_if(struct hard_iface *hard_iface, int max_if_num)
 592 {
 593         struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 594         struct hashtable_t *hash = bat_priv->orig_hash;
 595         struct hlist_node *node;
 596         struct hlist_head *head;
 597         struct hard_iface *hard_iface_tmp;
 598         struct orig_node *orig_node;
 599         uint32_t i;
 600         int ret;
 601
 602         /* resize all orig nodes because orig_node->bcast_own(_sum) depend on
 603          * if_num */
 604         for (i = 0; i < hash->size; i++) {
 605                 head = &hash->table[i];
 606
 607                 rcu_read_lock();
 608                 hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
 609                         spin_lock_bh(&orig_node->ogm_cnt_lock);
 610                         ret = orig_node_del_if(orig_node, max_if_num,
 611                                         hard_iface->if_num);
 612                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
 613
 614                         if (ret == -1)
 615                                 goto err;
 616                 }
 617                 rcu_read_unlock();
 618         }
 619
 620         /* renumber remaining batman interfaces _inside_ of orig_hash_lock */
 621         rcu_read_lock();
 622         list_for_each_entry_rcu(hard_iface_tmp, &hardif_list, list) {
 623                 if (hard_iface_tmp->if_status == IF_NOT_IN_USE)
 624                         continue;
 625
 626                 if (hard_iface == hard_iface_tmp)
 627                         continue;
 628
 629                 if (hard_iface->soft_iface != hard_iface_tmp->soft_iface)
 630                         continue;
 631
 632                 if (hard_iface_tmp->if_num > hard_iface->if_num)
 633                         hard_iface_tmp->if_num--;
 634         }
 635         rcu_read_unlock();
 636
 637         hard_iface->if_num = -1;
 638         return 0;
 639
 640 err:
 641         rcu_read_unlock();
 642         return -ENOMEM;
 643 }