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 #include "network-coding.h" 32 33 /* hash class keys */ 34 static struct lock_class_key batadv_orig_hash_lock_class_key; 35 36 static void batadv_purge_orig(struct work_struct *work); 37 38 /* returns 1 if they are the same originator */ 39 static int batadv_compare_orig(const struct hlist_node *node, const void *data2) 40 { 41 const void *data1 = container_of(node, struct batadv_orig_node, 42 hash_entry); 43 44 return (memcmp(data1, data2, ETH_ALEN) == 0 ? 1 : 0); 45 } 46 47 int batadv_originator_init(struct batadv_priv *bat_priv) 48 { 49 if (bat_priv->orig_hash) 50 return 0; 51 52 bat_priv->orig_hash = batadv_hash_new(1024); 53 54 if (!bat_priv->orig_hash) 55 goto err; 56 57 batadv_hash_set_lock_class(bat_priv->orig_hash, 58 &batadv_orig_hash_lock_class_key); 59 60 INIT_DELAYED_WORK(&bat_priv->orig_work, batadv_purge_orig); 61 queue_delayed_work(batadv_event_workqueue, 62 &bat_priv->orig_work, 63 msecs_to_jiffies(BATADV_ORIG_WORK_PERIOD)); 64 65 return 0; 66 67 err: 68 return -ENOMEM; 69 } 70 71 void batadv_neigh_node_free_ref(struct batadv_neigh_node *neigh_node) 72 { 73 if (atomic_dec_and_test(&neigh_node->refcount)) 74 kfree_rcu(neigh_node, rcu); 75 } 76 77 /* increases the refcounter of a found router */ 78 struct batadv_neigh_node * 79 batadv_orig_node_get_router(struct batadv_orig_node *orig_node) 80 { 81 struct batadv_neigh_node *router; 82 83 rcu_read_lock(); 84 router = rcu_dereference(orig_node->router); 85 86 if (router && !atomic_inc_not_zero(&router->refcount)) 87 router = NULL; 88 89 rcu_read_unlock(); 90 return router; 91 } 92 93 struct batadv_neigh_node * 94 batadv_neigh_node_new(struct batadv_hard_iface *hard_iface, 95 const uint8_t *neigh_addr, uint32_t seqno) 96 { 97 struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface); 98 struct batadv_neigh_node *neigh_node; 99 100 neigh_node = kzalloc(sizeof(*neigh_node), GFP_ATOMIC); 101 if (!neigh_node) 102 goto out; 103 104 INIT_HLIST_NODE(&neigh_node->list); 105 106 memcpy(neigh_node->addr, neigh_addr, ETH_ALEN); 107 spin_lock_init(&neigh_node->lq_update_lock); 108 109 /* extra reference for return */ 110 atomic_set(&neigh_node->refcount, 2); 111 112 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 113 "Creating new neighbor %pM, initial seqno %d\n", 114 neigh_addr, seqno); 115 116 out: 117 return neigh_node; 118 } 119 120 static void batadv_orig_node_free_rcu(struct rcu_head *rcu) 121 { 122 struct hlist_node *node_tmp; 123 struct batadv_neigh_node *neigh_node, *tmp_neigh_node; 124 struct batadv_orig_node *orig_node; 125 126 orig_node = container_of(rcu, struct batadv_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 batadv_neigh_node_free_ref(neigh_node); 135 } 136 137 /* for all neighbors towards this originator ... */ 138 hlist_for_each_entry_safe(neigh_node, node_tmp, 139 &orig_node->neigh_list, list) { 140 hlist_del_rcu(&neigh_node->list); 141 batadv_neigh_node_free_ref(neigh_node); 142 } 143 144 spin_unlock_bh(&orig_node->neigh_list_lock); 145 146 /* Free nc_nodes */ 147 batadv_nc_purge_orig(orig_node->bat_priv, orig_node, NULL); 148 149 batadv_frag_list_free(&orig_node->frag_list); 150 batadv_tt_global_del_orig(orig_node->bat_priv, orig_node, 151 "originator timed out"); 152 153 kfree(orig_node->tt_buff); 154 kfree(orig_node->bcast_own); 155 kfree(orig_node->bcast_own_sum); 156 kfree(orig_node); 157 } 158 159 /** 160 * batadv_orig_node_free_ref - decrement the orig node refcounter and possibly 161 * schedule an rcu callback for freeing it 162 * @orig_node: the orig node to free 163 */ 164 void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node) 165 { 166 if (atomic_dec_and_test(&orig_node->refcount)) 167 call_rcu(&orig_node->rcu, batadv_orig_node_free_rcu); 168 } 169 170 /** 171 * batadv_orig_node_free_ref_now - decrement the orig node refcounter and 172 * possibly free it (without rcu callback) 173 * @orig_node: the orig node to free 174 */ 175 void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node) 176 { 177 if (atomic_dec_and_test(&orig_node->refcount)) 178 batadv_orig_node_free_rcu(&orig_node->rcu); 179 } 180 181 void batadv_originator_free(struct batadv_priv *bat_priv) 182 { 183 struct batadv_hashtable *hash = bat_priv->orig_hash; 184 struct hlist_node *node_tmp; 185 struct hlist_head *head; 186 spinlock_t *list_lock; /* spinlock to protect write access */ 187 struct batadv_orig_node *orig_node; 188 uint32_t i; 189 190 if (!hash) 191 return; 192 193 cancel_delayed_work_sync(&bat_priv->orig_work); 194 195 bat_priv->orig_hash = NULL; 196 197 for (i = 0; i < hash->size; i++) { 198 head = &hash->table[i]; 199 list_lock = &hash->list_locks[i]; 200 201 spin_lock_bh(list_lock); 202 hlist_for_each_entry_safe(orig_node, node_tmp, 203 head, hash_entry) { 204 hlist_del_rcu(&orig_node->hash_entry); 205 batadv_orig_node_free_ref(orig_node); 206 } 207 spin_unlock_bh(list_lock); 208 } 209 210 batadv_hash_destroy(hash); 211 } 212 213 /* this function finds or creates an originator entry for the given 214 * address if it does not exits 215 */ 216 struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv, 217 const uint8_t *addr) 218 { 219 struct batadv_orig_node *orig_node; 220 int size; 221 int hash_added; 222 unsigned long reset_time; 223 224 orig_node = batadv_orig_hash_find(bat_priv, addr); 225 if (orig_node) 226 return orig_node; 227 228 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 229 "Creating new originator: %pM\n", addr); 230 231 orig_node = kzalloc(sizeof(*orig_node), GFP_ATOMIC); 232 if (!orig_node) 233 return NULL; 234 235 INIT_HLIST_HEAD(&orig_node->neigh_list); 236 INIT_LIST_HEAD(&orig_node->bond_list); 237 spin_lock_init(&orig_node->ogm_cnt_lock); 238 spin_lock_init(&orig_node->bcast_seqno_lock); 239 spin_lock_init(&orig_node->neigh_list_lock); 240 spin_lock_init(&orig_node->tt_buff_lock); 241 242 batadv_nc_init_orig(orig_node); 243 244 /* extra reference for return */ 245 atomic_set(&orig_node->refcount, 2); 246 247 orig_node->tt_initialised = false; 248 orig_node->bat_priv = bat_priv; 249 memcpy(orig_node->orig, addr, ETH_ALEN); 250 batadv_dat_init_orig_node_addr(orig_node); 251 orig_node->router = NULL; 252 orig_node->tt_crc = 0; 253 atomic_set(&orig_node->last_ttvn, 0); 254 orig_node->tt_buff = NULL; 255 orig_node->tt_buff_len = 0; 256 atomic_set(&orig_node->tt_size, 0); 257 reset_time = jiffies - 1 - msecs_to_jiffies(BATADV_RESET_PROTECTION_MS); 258 orig_node->bcast_seqno_reset = reset_time; 259 orig_node->batman_seqno_reset = reset_time; 260 261 atomic_set(&orig_node->bond_candidates, 0); 262 263 size = bat_priv->num_ifaces * sizeof(unsigned long) * BATADV_NUM_WORDS; 264 265 orig_node->bcast_own = kzalloc(size, GFP_ATOMIC); 266 if (!orig_node->bcast_own) 267 goto free_orig_node; 268 269 size = bat_priv->num_ifaces * sizeof(uint8_t); 270 orig_node->bcast_own_sum = kzalloc(size, GFP_ATOMIC); 271 272 INIT_LIST_HEAD(&orig_node->frag_list); 273 orig_node->last_frag_packet = 0; 274 275 if (!orig_node->bcast_own_sum) 276 goto free_bcast_own; 277 278 hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig, 279 batadv_choose_orig, orig_node, 280 &orig_node->hash_entry); 281 if (hash_added != 0) 282 goto free_bcast_own_sum; 283 284 return orig_node; 285 free_bcast_own_sum: 286 kfree(orig_node->bcast_own_sum); 287 free_bcast_own: 288 kfree(orig_node->bcast_own); 289 free_orig_node: 290 kfree(orig_node); 291 return NULL; 292 } 293 294 static bool 295 batadv_purge_orig_neighbors(struct batadv_priv *bat_priv, 296 struct batadv_orig_node *orig_node, 297 struct batadv_neigh_node **best_neigh_node) 298 { 299 struct hlist_node *node_tmp; 300 struct batadv_neigh_node *neigh_node; 301 bool neigh_purged = false; 302 unsigned long last_seen; 303 struct batadv_hard_iface *if_incoming; 304 305 *best_neigh_node = NULL; 306 307 spin_lock_bh(&orig_node->neigh_list_lock); 308 309 /* for all neighbors towards this originator ... */ 310 hlist_for_each_entry_safe(neigh_node, node_tmp, 311 &orig_node->neigh_list, list) { 312 last_seen = neigh_node->last_seen; 313 if_incoming = neigh_node->if_incoming; 314 315 if ((batadv_has_timed_out(last_seen, BATADV_PURGE_TIMEOUT)) || 316 (if_incoming->if_status == BATADV_IF_INACTIVE) || 317 (if_incoming->if_status == BATADV_IF_NOT_IN_USE) || 318 (if_incoming->if_status == BATADV_IF_TO_BE_REMOVED)) { 319 if ((if_incoming->if_status == BATADV_IF_INACTIVE) || 320 (if_incoming->if_status == BATADV_IF_NOT_IN_USE) || 321 (if_incoming->if_status == BATADV_IF_TO_BE_REMOVED)) 322 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 323 "neighbor purge: originator %pM, neighbor: %pM, iface: %s\n", 324 orig_node->orig, neigh_node->addr, 325 if_incoming->net_dev->name); 326 else 327 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 328 "neighbor timeout: originator %pM, neighbor: %pM, last_seen: %u\n", 329 orig_node->orig, neigh_node->addr, 330 jiffies_to_msecs(last_seen)); 331 332 neigh_purged = true; 333 334 hlist_del_rcu(&neigh_node->list); 335 batadv_bonding_candidate_del(orig_node, neigh_node); 336 batadv_neigh_node_free_ref(neigh_node); 337 } else { 338 if ((!*best_neigh_node) || 339 (neigh_node->tq_avg > (*best_neigh_node)->tq_avg)) 340 *best_neigh_node = neigh_node; 341 } 342 } 343 344 spin_unlock_bh(&orig_node->neigh_list_lock); 345 return neigh_purged; 346 } 347 348 static bool batadv_purge_orig_node(struct batadv_priv *bat_priv, 349 struct batadv_orig_node *orig_node) 350 { 351 struct batadv_neigh_node *best_neigh_node; 352 353 if (batadv_has_timed_out(orig_node->last_seen, 354 2 * BATADV_PURGE_TIMEOUT)) { 355 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 356 "Originator timeout: originator %pM, last_seen %u\n", 357 orig_node->orig, 358 jiffies_to_msecs(orig_node->last_seen)); 359 return true; 360 } else { 361 if (batadv_purge_orig_neighbors(bat_priv, orig_node, 362 &best_neigh_node)) 363 batadv_update_route(bat_priv, orig_node, 364 best_neigh_node); 365 } 366 367 return false; 368 } 369 370 static void _batadv_purge_orig(struct batadv_priv *bat_priv) 371 { 372 struct batadv_hashtable *hash = bat_priv->orig_hash; 373 struct hlist_node *node_tmp; 374 struct hlist_head *head; 375 spinlock_t *list_lock; /* spinlock to protect write access */ 376 struct batadv_orig_node *orig_node; 377 uint32_t i; 378 379 if (!hash) 380 return; 381 382 /* for all origins... */ 383 for (i = 0; i < hash->size; i++) { 384 head = &hash->table[i]; 385 list_lock = &hash->list_locks[i]; 386 387 spin_lock_bh(list_lock); 388 hlist_for_each_entry_safe(orig_node, node_tmp, 389 head, hash_entry) { 390 if (batadv_purge_orig_node(bat_priv, orig_node)) { 391 if (orig_node->gw_flags) 392 batadv_gw_node_delete(bat_priv, 393 orig_node); 394 hlist_del_rcu(&orig_node->hash_entry); 395 batadv_orig_node_free_ref(orig_node); 396 continue; 397 } 398 399 if (batadv_has_timed_out(orig_node->last_frag_packet, 400 BATADV_FRAG_TIMEOUT)) 401 batadv_frag_list_free(&orig_node->frag_list); 402 } 403 spin_unlock_bh(list_lock); 404 } 405 406 batadv_gw_node_purge(bat_priv); 407 batadv_gw_election(bat_priv); 408 } 409 410 static void batadv_purge_orig(struct work_struct *work) 411 { 412 struct delayed_work *delayed_work; 413 struct batadv_priv *bat_priv; 414 415 delayed_work = container_of(work, struct delayed_work, work); 416 bat_priv = container_of(delayed_work, struct batadv_priv, orig_work); 417 _batadv_purge_orig(bat_priv); 418 queue_delayed_work(batadv_event_workqueue, 419 &bat_priv->orig_work, 420 msecs_to_jiffies(BATADV_ORIG_WORK_PERIOD)); 421 } 422 423 void batadv_purge_orig_ref(struct batadv_priv *bat_priv) 424 { 425 _batadv_purge_orig(bat_priv); 426 } 427 428 int batadv_orig_seq_print_text(struct seq_file *seq, void *offset) 429 { 430 struct net_device *net_dev = (struct net_device *)seq->private; 431 struct batadv_priv *bat_priv = netdev_priv(net_dev); 432 struct batadv_hashtable *hash = bat_priv->orig_hash; 433 struct hlist_head *head; 434 struct batadv_hard_iface *primary_if; 435 struct batadv_orig_node *orig_node; 436 struct batadv_neigh_node *neigh_node, *neigh_node_tmp; 437 int batman_count = 0; 438 int last_seen_secs; 439 int last_seen_msecs; 440 unsigned long last_seen_jiffies; 441 uint32_t i; 442 443 primary_if = batadv_seq_print_text_primary_if_get(seq); 444 if (!primary_if) 445 goto out; 446 447 seq_printf(seq, "[B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n", 448 BATADV_SOURCE_VERSION, primary_if->net_dev->name, 449 primary_if->net_dev->dev_addr, net_dev->name); 450 seq_printf(seq, " %-15s %s (%s/%i) %17s [%10s]: %20s ...\n", 451 "Originator", "last-seen", "#", BATADV_TQ_MAX_VALUE, 452 "Nexthop", "outgoingIF", "Potential nexthops"); 453 454 for (i = 0; i < hash->size; i++) { 455 head = &hash->table[i]; 456 457 rcu_read_lock(); 458 hlist_for_each_entry_rcu(orig_node, head, hash_entry) { 459 neigh_node = batadv_orig_node_get_router(orig_node); 460 if (!neigh_node) 461 continue; 462 463 if (neigh_node->tq_avg == 0) 464 goto next; 465 466 last_seen_jiffies = jiffies - orig_node->last_seen; 467 last_seen_msecs = jiffies_to_msecs(last_seen_jiffies); 468 last_seen_secs = last_seen_msecs / 1000; 469 last_seen_msecs = last_seen_msecs % 1000; 470 471 seq_printf(seq, "%pM %4i.%03is (%3i) %pM [%10s]:", 472 orig_node->orig, last_seen_secs, 473 last_seen_msecs, neigh_node->tq_avg, 474 neigh_node->addr, 475 neigh_node->if_incoming->net_dev->name); 476 477 hlist_for_each_entry_rcu(neigh_node_tmp, 478 &orig_node->neigh_list, list) { 479 seq_printf(seq, " %pM (%3i)", 480 neigh_node_tmp->addr, 481 neigh_node_tmp->tq_avg); 482 } 483 484 seq_puts(seq, "\n"); 485 batman_count++; 486 487 next: 488 batadv_neigh_node_free_ref(neigh_node); 489 } 490 rcu_read_unlock(); 491 } 492 493 if (batman_count == 0) 494 seq_puts(seq, "No batman nodes in range ...\n"); 495 496 out: 497 if (primary_if) 498 batadv_hardif_free_ref(primary_if); 499 return 0; 500 } 501 502 static int batadv_orig_node_add_if(struct batadv_orig_node *orig_node, 503 int max_if_num) 504 { 505 void *data_ptr; 506 size_t data_size, old_size; 507 508 data_size = max_if_num * sizeof(unsigned long) * BATADV_NUM_WORDS; 509 old_size = (max_if_num - 1) * sizeof(unsigned long) * BATADV_NUM_WORDS; 510 data_ptr = kmalloc(data_size, GFP_ATOMIC); 511 if (!data_ptr) 512 return -ENOMEM; 513 514 memcpy(data_ptr, orig_node->bcast_own, old_size); 515 kfree(orig_node->bcast_own); 516 orig_node->bcast_own = data_ptr; 517 518 data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC); 519 if (!data_ptr) 520 return -ENOMEM; 521 522 memcpy(data_ptr, orig_node->bcast_own_sum, 523 (max_if_num - 1) * sizeof(uint8_t)); 524 kfree(orig_node->bcast_own_sum); 525 orig_node->bcast_own_sum = data_ptr; 526 527 return 0; 528 } 529 530 int batadv_orig_hash_add_if(struct batadv_hard_iface *hard_iface, 531 int max_if_num) 532 { 533 struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface); 534 struct batadv_hashtable *hash = bat_priv->orig_hash; 535 struct hlist_head *head; 536 struct batadv_orig_node *orig_node; 537 uint32_t i; 538 int ret; 539 540 /* resize all orig nodes because orig_node->bcast_own(_sum) depend on 541 * if_num 542 */ 543 for (i = 0; i < hash->size; i++) { 544 head = &hash->table[i]; 545 546 rcu_read_lock(); 547 hlist_for_each_entry_rcu(orig_node, head, hash_entry) { 548 spin_lock_bh(&orig_node->ogm_cnt_lock); 549 ret = batadv_orig_node_add_if(orig_node, max_if_num); 550 spin_unlock_bh(&orig_node->ogm_cnt_lock); 551 552 if (ret == -ENOMEM) 553 goto err; 554 } 555 rcu_read_unlock(); 556 } 557 558 return 0; 559 560 err: 561 rcu_read_unlock(); 562 return -ENOMEM; 563 } 564 565 static int batadv_orig_node_del_if(struct batadv_orig_node *orig_node, 566 int max_if_num, int del_if_num) 567 { 568 void *data_ptr = NULL; 569 int chunk_size; 570 571 /* last interface was removed */ 572 if (max_if_num == 0) 573 goto free_bcast_own; 574 575 chunk_size = sizeof(unsigned long) * BATADV_NUM_WORDS; 576 data_ptr = kmalloc(max_if_num * chunk_size, GFP_ATOMIC); 577 if (!data_ptr) 578 return -ENOMEM; 579 580 /* copy first part */ 581 memcpy(data_ptr, orig_node->bcast_own, del_if_num * chunk_size); 582 583 /* copy second part */ 584 memcpy((char *)data_ptr + del_if_num * chunk_size, 585 orig_node->bcast_own + ((del_if_num + 1) * chunk_size), 586 (max_if_num - del_if_num) * chunk_size); 587 588 free_bcast_own: 589 kfree(orig_node->bcast_own); 590 orig_node->bcast_own = data_ptr; 591 592 if (max_if_num == 0) 593 goto free_own_sum; 594 595 data_ptr = kmalloc(max_if_num * sizeof(uint8_t), GFP_ATOMIC); 596 if (!data_ptr) 597 return -ENOMEM; 598 599 memcpy(data_ptr, orig_node->bcast_own_sum, 600 del_if_num * sizeof(uint8_t)); 601 602 memcpy((char *)data_ptr + del_if_num * sizeof(uint8_t), 603 orig_node->bcast_own_sum + ((del_if_num + 1) * sizeof(uint8_t)), 604 (max_if_num - del_if_num) * sizeof(uint8_t)); 605 606 free_own_sum: 607 kfree(orig_node->bcast_own_sum); 608 orig_node->bcast_own_sum = data_ptr; 609 610 return 0; 611 } 612 613 int batadv_orig_hash_del_if(struct batadv_hard_iface *hard_iface, 614 int max_if_num) 615 { 616 struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface); 617 struct batadv_hashtable *hash = bat_priv->orig_hash; 618 struct hlist_head *head; 619 struct batadv_hard_iface *hard_iface_tmp; 620 struct batadv_orig_node *orig_node; 621 uint32_t i; 622 int ret; 623 624 /* resize all orig nodes because orig_node->bcast_own(_sum) depend on 625 * if_num 626 */ 627 for (i = 0; i < hash->size; i++) { 628 head = &hash->table[i]; 629 630 rcu_read_lock(); 631 hlist_for_each_entry_rcu(orig_node, head, hash_entry) { 632 spin_lock_bh(&orig_node->ogm_cnt_lock); 633 ret = batadv_orig_node_del_if(orig_node, max_if_num, 634 hard_iface->if_num); 635 spin_unlock_bh(&orig_node->ogm_cnt_lock); 636 637 if (ret == -ENOMEM) 638 goto err; 639 } 640 rcu_read_unlock(); 641 } 642 643 /* renumber remaining batman interfaces _inside_ of orig_hash_lock */ 644 rcu_read_lock(); 645 list_for_each_entry_rcu(hard_iface_tmp, &batadv_hardif_list, list) { 646 if (hard_iface_tmp->if_status == BATADV_IF_NOT_IN_USE) 647 continue; 648 649 if (hard_iface == hard_iface_tmp) 650 continue; 651 652 if (hard_iface->soft_iface != hard_iface_tmp->soft_iface) 653 continue; 654 655 if (hard_iface_tmp->if_num > hard_iface->if_num) 656 hard_iface_tmp->if_num--; 657 } 658 rcu_read_unlock(); 659 660 hard_iface->if_num = -1; 661 return 0; 662 663 err: 664 rcu_read_unlock(); 665 return -ENOMEM; 666 } 667