Pileus Git - ~andy/linux/blob - net/batman-adv/originator.c

   1 /* Copyright (C) 2009-2013 B.A.T.M.A.N. contributors:
   2  *
   3  * Marek Lindner, Simon Wunderlich
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 2 of the GNU General Public
   7  * License as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA
  18  */
  19
  20 #include "main.h"
  21 #include "distributed-arp-table.h"
  22 #include "originator.h"
  23 #include "hash.h"
  24 #include "translation-table.h"
  25 #include "routing.h"
  26 #include "gateway_client.h"
  27 #include "hard-interface.h"
  28 #include "unicast.h"
  29 #include "soft-interface.h"
  30 #include "bridge_loop_avoidance.h"
  31
  32 /* hash class keys */
  33 static struct lock_class_key batadv_orig_hash_lock_class_key;
  34
  35 static void batadv_purge_orig(struct work_struct *work);
  36
  37 /* returns 1 if they are the same originator */
  38 static int batadv_compare_orig(const struct hlist_node *node, const void *data2)
  39 {
  40         const void *data1 = container_of(node, struct batadv_orig_node,
  41                                          hash_entry);
  42
  43         return (memcmp(data1, data2, ETH_ALEN) == 0 ? 1 : 0);
  44 }
  45
  46 int batadv_originator_init(struct batadv_priv *bat_priv)
  47 {
  48         if (bat_priv->orig_hash)
  49                 return 0;
  50
  51         bat_priv->orig_hash = batadv_hash_new(1024);
  52
  53         if (!bat_priv->orig_hash)
  54                 goto err;
  55
  56         batadv_hash_set_lock_class(bat_priv->orig_hash,
  57                                    &batadv_orig_hash_lock_class_key);
  58
  59         INIT_DELAYED_WORK(&bat_priv->orig_work, batadv_purge_orig);
  60         queue_delayed_work(batadv_event_workqueue,
  61                            &bat_priv->orig_work,
  62                            msecs_to_jiffies(BATADV_ORIG_WORK_PERIOD));
  63
  64         return 0;
  65
  66 err:
  67         return -ENOMEM;
  68 }
  69
  70 void batadv_neigh_node_free_ref(struct batadv_neigh_node *neigh_node)
  71 {
  72         if (atomic_dec_and_test(&neigh_node->refcount))
  73                 kfree_rcu(neigh_node, rcu);
  74 }
  75
  76 /* increases the refcounter of a found router */
  77 struct batadv_neigh_node *
  78 batadv_orig_node_get_router(struct batadv_orig_node *orig_node)
  79 {
  80         struct batadv_neigh_node *router;
  81
  82         rcu_read_lock();
  83         router = rcu_dereference(orig_node->router);
  84
  85         if (router && !atomic_inc_not_zero(&router->refcount))
  86                 router = NULL;
  87
  88         rcu_read_unlock();
  89         return router;
  90 }
  91
  92 struct batadv_neigh_node *
  93 batadv_neigh_node_new(struct batadv_hard_iface *hard_iface,
  94                       const uint8_t *neigh_addr, uint32_t seqno)
  95 {
  96         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
  97         struct batadv_neigh_node *neigh_node;
  98
  99         neigh_node = kzalloc(sizeof(*neigh_node), GFP_ATOMIC);
 100         if (!neigh_node)
 101                 goto out;
 102
 103         INIT_HLIST_NODE(&neigh_node->list);
 104
 105         memcpy(neigh_node->addr, neigh_addr, ETH_ALEN);
 106         spin_lock_init(&neigh_node->lq_update_lock);
 107
 108         /* extra reference for return */
 109         atomic_set(&neigh_node->refcount, 2);
 110
 111         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 112                    "Creating new neighbor %pM, initial seqno %d\n",
 113                    neigh_addr, seqno);
 114
 115 out:
 116         return neigh_node;
 117 }
 118
 119 static void batadv_orig_node_free_rcu(struct rcu_head *rcu)
 120 {
 121         struct hlist_node *node_tmp;
 122         struct batadv_neigh_node *neigh_node, *tmp_neigh_node;
 123         struct batadv_orig_node *orig_node;
 124
 125         orig_node = container_of(rcu, struct batadv_orig_node, rcu);
 126
 127         spin_lock_bh(&orig_node->neigh_list_lock);
 128
 129         /* for all bonding members ... */
 130         list_for_each_entry_safe(neigh_node, tmp_neigh_node,
 131                                  &orig_node->bond_list, bonding_list) {
 132                 list_del_rcu(&neigh_node->bonding_list);
 133                 batadv_neigh_node_free_ref(neigh_node);
 134         }
 135
 136         /* for all neighbors towards this originator ... */
 137         hlist_for_each_entry_safe(neigh_node, node_tmp,
 138                                   &orig_node->neigh_list, list) {
 139                 hlist_del_rcu(&neigh_node->list);
 140                 batadv_neigh_node_free_ref(neigh_node);
 141         }
 142
 143         spin_unlock_bh(&orig_node->neigh_list_lock);
 144
 145         batadv_frag_list_free(&orig_node->frag_list);
 146         batadv_tt_global_del_orig(orig_node->bat_priv, orig_node,
 147                                   "originator timed out");
 148
 149         kfree(orig_node->tt_buff);
 150         kfree(orig_node->bcast_own);
 151         kfree(orig_node->bcast_own_sum);
 152         kfree(orig_node);
 153 }
 154
 155 void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node)
 156 {
 157         if (atomic_dec_and_test(&orig_node->refcount))
 158                 call_rcu(&orig_node->rcu, batadv_orig_node_free_rcu);
 159 }
 160
 161 void batadv_originator_free(struct batadv_priv *bat_priv)
 162 {
 163         struct batadv_hashtable *hash = bat_priv->orig_hash;
 164         struct hlist_node *node_tmp;
 165         struct hlist_head *head;
 166         spinlock_t *list_lock; /* spinlock to protect write access */
 167         struct batadv_orig_node *orig_node;
 168         uint32_t i;
 169
 170         if (!hash)
 171                 return;
 172
 173         cancel_delayed_work_sync(&bat_priv->orig_work);
 174
 175         bat_priv->orig_hash = NULL;
 176
 177         for (i = 0; i < hash->size; i++) {
 178                 head = &hash->table[i];
 179                 list_lock = &hash->list_locks[i];
 180
 181                 spin_lock_bh(list_lock);
 182                 hlist_for_each_entry_safe(orig_node, node_tmp,
 183                                           head, hash_entry) {
 184                         hlist_del_rcu(&orig_node->hash_entry);
 185                         batadv_orig_node_free_ref(orig_node);
 186                 }
 187                 spin_unlock_bh(list_lock);
 188         }
 189
 190         batadv_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  */
 196 struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv,
 197                                               const uint8_t *addr)
 198 {
 199         struct batadv_orig_node *orig_node;
 200         int size;
 201         int hash_added;
 202         unsigned long reset_time;
 203
 204         orig_node = batadv_orig_hash_find(bat_priv, addr);
 205         if (orig_node)
 206                 return orig_node;
 207
 208         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 209                    "Creating new originator: %pM\n", addr);
 210
 211         orig_node = kzalloc(sizeof(*orig_node), GFP_ATOMIC);
 212         if (!orig_node)
 213                 return NULL;
 214
 215         INIT_HLIST_HEAD(&orig_node->neigh_list);
 216         INIT_LIST_HEAD(&orig_node->bond_list);
 217         spin_lock_init(&orig_node->ogm_cnt_lock);
 218         spin_lock_init(&orig_node->bcast_seqno_lock);
 219         spin_lock_init(&orig_node->neigh_list_lock);
 220         spin_lock_init(&orig_node->tt_buff_lock);
 221
 222         /* extra reference for return */
 223         atomic_set(&orig_node->refcount, 2);
 224
 225         orig_node->tt_initialised = false;
 226         orig_node->bat_priv = bat_priv;
 227         memcpy(orig_node->orig, addr, ETH_ALEN);
 228         batadv_dat_init_orig_node_addr(orig_node);
 229         orig_node->router = NULL;
 230         orig_node->tt_crc = 0;
 231         atomic_set(&orig_node->last_ttvn, 0);
 232         orig_node->tt_buff = NULL;
 233         orig_node->tt_buff_len = 0;
 234         atomic_set(&orig_node->tt_size, 0);
 235         reset_time = jiffies - 1 - msecs_to_jiffies(BATADV_RESET_PROTECTION_MS);
 236         orig_node->bcast_seqno_reset = reset_time;
 237         orig_node->batman_seqno_reset = reset_time;
 238
 239         atomic_set(&orig_node->bond_candidates, 0);
 240
 241         size = bat_priv->num_ifaces * sizeof(unsigned long) * BATADV_NUM_WORDS;
 242
 243         orig_node->bcast_own = kzalloc(size, GFP_ATOMIC);
 244         if (!orig_node->bcast_own)
 245                 goto free_orig_node;
 246
 247         size = bat_priv->num_ifaces * sizeof(uint8_t);
 248         orig_node->bcast_own_sum = kzalloc(size, GFP_ATOMIC);
 249
 250         INIT_LIST_HEAD(&orig_node->frag_list);
 251         orig_node->last_frag_packet = 0;
 252
 253         if (!orig_node->bcast_own_sum)
 254                 goto free_bcast_own;
 255
 256         hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
 257                                      batadv_choose_orig, orig_node,
 258                                      &orig_node->hash_entry);
 259         if (hash_added != 0)
 260                 goto free_bcast_own_sum;
 261
 262         return orig_node;
 263 free_bcast_own_sum:
 264         kfree(orig_node->bcast_own_sum);
 265 free_bcast_own:
 266         kfree(orig_node->bcast_own);
 267 free_orig_node:
 268         kfree(orig_node);
 269         return NULL;
 270 }
 271
 272 static bool
 273 batadv_purge_orig_neighbors(struct batadv_priv *bat_priv,
 274                             struct batadv_orig_node *orig_node,
 275                             struct batadv_neigh_node **best_neigh_node)
 276 {
 277         struct hlist_node *node_tmp;
 278         struct batadv_neigh_node *neigh_node;
 279         bool neigh_purged = false;
 280         unsigned long last_seen;
 281         struct batadv_hard_iface *if_incoming;
 282
 283         *best_neigh_node = NULL;
 284
 285         spin_lock_bh(&orig_node->neigh_list_lock);
 286
 287         /* for all neighbors towards this originator ... */
 288         hlist_for_each_entry_safe(neigh_node, node_tmp,
 289                                   &orig_node->neigh_list, list) {
 290                 last_seen = neigh_node->last_seen;
 291                 if_incoming = neigh_node->if_incoming;
 292
 293                 if ((batadv_has_timed_out(last_seen, BATADV_PURGE_TIMEOUT)) ||
 294                     (if_incoming->if_status == BATADV_IF_INACTIVE) ||
 295                     (if_incoming->if_status == BATADV_IF_NOT_IN_USE) ||
 296                     (if_incoming->if_status == BATADV_IF_TO_BE_REMOVED)) {
 297                         if ((if_incoming->if_status == BATADV_IF_INACTIVE) ||
 298                             (if_incoming->if_status == BATADV_IF_NOT_IN_USE) ||
 299                             (if_incoming->if_status == BATADV_IF_TO_BE_REMOVED))
 300                                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 301                                            "neighbor purge: originator %pM, neighbor: %pM, iface: %s\n",
 302                                            orig_node->orig, neigh_node->addr,
 303                                            if_incoming->net_dev->name);
 304                         else
 305                                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 306                                            "neighbor timeout: originator %pM, neighbor: %pM, last_seen: %u\n",
 307                                            orig_node->orig, neigh_node->addr,
 308                                            jiffies_to_msecs(last_seen));
 309
 310                         neigh_purged = true;
 311
 312                         hlist_del_rcu(&neigh_node->list);
 313                         batadv_bonding_candidate_del(orig_node, neigh_node);
 314                         batadv_neigh_node_free_ref(neigh_node);
 315                 } else {
 316                         if ((!*best_neigh_node) ||
 317                             (neigh_node->tq_avg > (*best_neigh_node)->tq_avg))
 318                                 *best_neigh_node = neigh_node;
 319                 }
 320         }
 321
 322         spin_unlock_bh(&orig_node->neigh_list_lock);
 323         return neigh_purged;
 324 }
 325
 326 static bool batadv_purge_orig_node(struct batadv_priv *bat_priv,
 327                                    struct batadv_orig_node *orig_node)
 328 {
 329         struct batadv_neigh_node *best_neigh_node;
 330
 331         if (batadv_has_timed_out(orig_node->last_seen,
 332                                  2 * BATADV_PURGE_TIMEOUT)) {
 333                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 334                            "Originator timeout: originator %pM, last_seen %u\n",
 335                            orig_node->orig,
 336                            jiffies_to_msecs(orig_node->last_seen));
 337                 return true;
 338         } else {
 339                 if (batadv_purge_orig_neighbors(bat_priv, orig_node,
 340                                                 &best_neigh_node))
 341                         batadv_update_route(bat_priv, orig_node,
 342                                             best_neigh_node);
 343         }
 344
 345         return false;
 346 }
 347
 348 static void _batadv_purge_orig(struct batadv_priv *bat_priv)
 349 {
 350         struct batadv_hashtable *hash = bat_priv->orig_hash;
 351         struct hlist_node *node_tmp;
 352         struct hlist_head *head;
 353         spinlock_t *list_lock; /* spinlock to protect write access */
 354         struct batadv_orig_node *orig_node;
 355         uint32_t i;
 356
 357         if (!hash)
 358                 return;
 359
 360         /* for all origins... */
 361         for (i = 0; i < hash->size; i++) {
 362                 head = &hash->table[i];
 363                 list_lock = &hash->list_locks[i];
 364
 365                 spin_lock_bh(list_lock);
 366                 hlist_for_each_entry_safe(orig_node, node_tmp,
 367                                           head, hash_entry) {
 368                         if (batadv_purge_orig_node(bat_priv, orig_node)) {
 369                                 if (orig_node->gw_flags)
 370                                         batadv_gw_node_delete(bat_priv,
 371                                                               orig_node);
 372                                 hlist_del_rcu(&orig_node->hash_entry);
 373                                 batadv_orig_node_free_ref(orig_node);
 374                                 continue;
 375                         }
 376
 377                         if (batadv_has_timed_out(orig_node->last_frag_packet,
 378                                                  BATADV_FRAG_TIMEOUT))
 379                                 batadv_frag_list_free(&orig_node->frag_list);
 380                 }
 381                 spin_unlock_bh(list_lock);
 382         }
 383
 384         batadv_gw_node_purge(bat_priv);
 385         batadv_gw_election(bat_priv);
 386 }
 387
 388 static void batadv_purge_orig(struct work_struct *work)
 389 {
 390         struct delayed_work *delayed_work;
 391         struct batadv_priv *bat_priv;
 392
 393         delayed_work = container_of(work, struct delayed_work, work);
 394         bat_priv = container_of(delayed_work, struct batadv_priv, orig_work);
 395         _batadv_purge_orig(bat_priv);
 396         queue_delayed_work(batadv_event_workqueue,
 397                            &bat_priv->orig_work,
 398                            msecs_to_jiffies(BATADV_ORIG_WORK_PERIOD));
 399 }
 400
 401 void batadv_purge_orig_ref(struct batadv_priv *bat_priv)
 402 {
 403         _batadv_purge_orig(bat_priv);
 404 }
 405
 406 int batadv_orig_seq_print_text(struct seq_file *seq, void *offset)
 407 {
 408         struct net_device *net_dev = (struct net_device *)seq->private;
 409         struct batadv_priv *bat_priv = netdev_priv(net_dev);
 410         struct batadv_hashtable *hash = bat_priv->orig_hash;
 411         struct hlist_head *head;
 412         struct batadv_hard_iface *primary_if;
 413         struct batadv_orig_node *orig_node;
 414         struct batadv_neigh_node *neigh_node, *neigh_node_tmp;
 415         int batman_count = 0;
 416         int last_seen_secs;
 417         int last_seen_msecs;
 418         unsigned long last_seen_jiffies;
 419         uint32_t i;
 420
 421         primary_if = batadv_seq_print_text_primary_if_get(seq);
 422         if (!primary_if)
 423                 goto out;
 424
 425         seq_printf(seq, "[B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
 426                    BATADV_SOURCE_VERSION, primary_if->net_dev->name,
 427                    primary_if->net_dev->dev_addr, net_dev->name);
 428         seq_printf(seq, "  %-15s %s (%s/%i) %17s [%10s]: %20s ...\n",
 429                    "Originator", "last-seen", "#", BATADV_TQ_MAX_VALUE,
 430                    "Nexthop", "outgoingIF", "Potential nexthops");
 431
 432         for (i = 0; i < hash->size; i++) {
 433                 head = &hash->table[i];
 434
 435                 rcu_read_lock();
 436                 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
 437                         neigh_node = batadv_orig_node_get_router(orig_node);
 438                         if (!neigh_node)
 439                                 continue;
 440
 441                         if (neigh_node->tq_avg == 0)
 442                                 goto next;
 443
 444                         last_seen_jiffies = jiffies - orig_node->last_seen;
 445                         last_seen_msecs = jiffies_to_msecs(last_seen_jiffies);
 446                         last_seen_secs = last_seen_msecs / 1000;
 447                         last_seen_msecs = last_seen_msecs % 1000;
 448
 449                         seq_printf(seq, "%pM %4i.%03is   (%3i) %pM [%10s]:",
 450                                    orig_node->orig, last_seen_secs,
 451                                    last_seen_msecs, neigh_node->tq_avg,
 452                                    neigh_node->addr,
 453                                    neigh_node->if_incoming->net_dev->name);
 454
 455                         hlist_for_each_entry_rcu(neigh_node_tmp,
 456                                                  &orig_node->neigh_list, list) {
 457                                 seq_printf(seq, " %pM (%3i)",
 458                                            neigh_node_tmp->addr,
 459                                            neigh_node_tmp->tq_avg);
 460                         }
 461
 462                         seq_printf(seq, "\n");
 463                         batman_count++;
 464
 465 next:
 466                         batadv_neigh_node_free_ref(neigh_node);
 467                 }
 468                 rcu_read_unlock();
 469         }
 470
 471         if (batman_count == 0)
 472                 seq_printf(seq, "No batman nodes in range ...\n");
 473
 474 out:
 475         if (primary_if)
 476                 batadv_hardif_free_ref(primary_if);
 477         return 0;
 478 }
 479
 480 static int batadv_orig_node_add_if(struct batadv_orig_node *orig_node,
 481                                    int max_if_num)
 482 {
 483         void *data_ptr;
 484         size_t data_size, old_size;
 485
 486         data_size = max_if_num * sizeof(unsigned long) * BATADV_NUM_WORDS;
 487         old_size = (max_if_num - 1) * sizeof(unsigned long) * BATADV_NUM_WORDS;
 488         data_ptr = kmalloc(data_size, GFP_ATOMIC);
 489         if (!data_ptr)
 490                 return -ENOMEM;
 491
 492         memcpy(data_ptr, orig_node->bcast_own, old_size);
 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                 return -ENOMEM;
 499
 500         memcpy(data_ptr, orig_node->bcast_own_sum,
 501                (max_if_num - 1) * sizeof(uint8_t));
 502         kfree(orig_node->bcast_own_sum);
 503         orig_node->bcast_own_sum = data_ptr;
 504
 505         return 0;
 506 }
 507
 508 int batadv_orig_hash_add_if(struct batadv_hard_iface *hard_iface,
 509                             int max_if_num)
 510 {
 511         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 512         struct batadv_hashtable *hash = bat_priv->orig_hash;
 513         struct hlist_head *head;
 514         struct batadv_orig_node *orig_node;
 515         uint32_t i;
 516         int ret;
 517
 518         /* resize all orig nodes because orig_node->bcast_own(_sum) depend on
 519          * if_num
 520          */
 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, head, hash_entry) {
 526                         spin_lock_bh(&orig_node->ogm_cnt_lock);
 527                         ret = batadv_orig_node_add_if(orig_node, max_if_num);
 528                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
 529
 530                         if (ret == -ENOMEM)
 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 batadv_orig_node_del_if(struct batadv_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) * BATADV_NUM_WORDS;
 554         data_ptr = kmalloc(max_if_num * chunk_size, GFP_ATOMIC);
 555         if (!data_ptr)
 556                 return -ENOMEM;
 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 -ENOMEM;
 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 batadv_orig_hash_del_if(struct batadv_hard_iface *hard_iface,
 592                             int max_if_num)
 593 {
 594         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 595         struct batadv_hashtable *hash = bat_priv->orig_hash;
 596         struct hlist_head *head;
 597         struct batadv_hard_iface *hard_iface_tmp;
 598         struct batadv_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          */
 605         for (i = 0; i < hash->size; i++) {
 606                 head = &hash->table[i];
 607
 608                 rcu_read_lock();
 609                 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
 610                         spin_lock_bh(&orig_node->ogm_cnt_lock);
 611                         ret = batadv_orig_node_del_if(orig_node, max_if_num,
 612                                                       hard_iface->if_num);
 613                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
 614
 615                         if (ret == -ENOMEM)
 616                                 goto err;
 617                 }
 618                 rcu_read_unlock();
 619         }
 620
 621         /* renumber remaining batman interfaces _inside_ of orig_hash_lock */
 622         rcu_read_lock();
 623         list_for_each_entry_rcu(hard_iface_tmp, &batadv_hardif_list, list) {
 624                 if (hard_iface_tmp->if_status == BATADV_IF_NOT_IN_USE)
 625                         continue;
 626
 627                 if (hard_iface == hard_iface_tmp)
 628                         continue;
 629
 630                 if (hard_iface->soft_iface != hard_iface_tmp->soft_iface)
 631                         continue;
 632
 633                 if (hard_iface_tmp->if_num > hard_iface->if_num)
 634                         hard_iface_tmp->if_num--;
 635         }
 636         rcu_read_unlock();
 637
 638         hard_iface->if_num = -1;
 639         return 0;
 640
 641 err:
 642         rcu_read_unlock();
 643         return -ENOMEM;
 644 }