net/batman-adv/routing.c

   1 /* Copyright (C) 2007-2013 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 "routing.h"
  22 #include "send.h"
  23 #include "soft-interface.h"
  24 #include "hard-interface.h"
  25 #include "icmp_socket.h"
  26 #include "translation-table.h"
  27 #include "originator.h"
  28 #include "vis.h"
  29 #include "unicast.h"
  30 #include "bridge_loop_avoidance.h"
  31 #include "distributed-arp-table.h"
  32
  33 static int batadv_route_unicast_packet(struct sk_buff *skb,
  34                                        struct batadv_hard_iface *recv_if);
  35
  36 void batadv_slide_own_bcast_window(struct batadv_hard_iface *hard_iface)
  37 {
  38         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
  39         struct batadv_hashtable *hash = bat_priv->orig_hash;
  40         struct hlist_node *node;
  41         struct hlist_head *head;
  42         struct batadv_orig_node *orig_node;
  43         unsigned long *word;
  44         uint32_t i;
  45         size_t word_index;
  46         uint8_t *w;
  47
  48         for (i = 0; i < hash->size; i++) {
  49                 head = &hash->table[i];
  50
  51                 rcu_read_lock();
  52                 hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
  53                         spin_lock_bh(&orig_node->ogm_cnt_lock);
  54                         word_index = hard_iface->if_num * BATADV_NUM_WORDS;
  55                         word = &(orig_node->bcast_own[word_index]);
  56
  57                         batadv_bit_get_packet(bat_priv, word, 1, 0);
  58                         w = &orig_node->bcast_own_sum[hard_iface->if_num];
  59                         *w = bitmap_weight(word, BATADV_TQ_LOCAL_WINDOW_SIZE);
  60                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
  61                 }
  62                 rcu_read_unlock();
  63         }
  64 }
  65
  66 static void _batadv_update_route(struct batadv_priv *bat_priv,
  67                                  struct batadv_orig_node *orig_node,
  68                                  struct batadv_neigh_node *neigh_node)
  69 {
  70         struct batadv_neigh_node *curr_router;
  71
  72         curr_router = batadv_orig_node_get_router(orig_node);
  73
  74         /* route deleted */
  75         if ((curr_router) && (!neigh_node)) {
  76                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  77                            "Deleting route towards: %pM\n", orig_node->orig);
  78                 batadv_tt_global_del_orig(bat_priv, orig_node,
  79                                           "Deleted route towards originator");
  80
  81         /* route added */
  82         } else if ((!curr_router) && (neigh_node)) {
  83                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  84                            "Adding route towards: %pM (via %pM)\n",
  85                            orig_node->orig, neigh_node->addr);
  86         /* route changed */
  87         } else if (neigh_node && curr_router) {
  88                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  89                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
  90                            orig_node->orig, neigh_node->addr,
  91                            curr_router->addr);
  92         }
  93
  94         if (curr_router)
  95                 batadv_neigh_node_free_ref(curr_router);
  96
  97         /* increase refcount of new best neighbor */
  98         if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
  99                 neigh_node = NULL;
 100
 101         spin_lock_bh(&orig_node->neigh_list_lock);
 102         rcu_assign_pointer(orig_node->router, neigh_node);
 103         spin_unlock_bh(&orig_node->neigh_list_lock);
 104
 105         /* decrease refcount of previous best neighbor */
 106         if (curr_router)
 107                 batadv_neigh_node_free_ref(curr_router);
 108 }
 109
 110 void batadv_update_route(struct batadv_priv *bat_priv,
 111                          struct batadv_orig_node *orig_node,
 112                          struct batadv_neigh_node *neigh_node)
 113 {
 114         struct batadv_neigh_node *router = NULL;
 115
 116         if (!orig_node)
 117                 goto out;
 118
 119         router = batadv_orig_node_get_router(orig_node);
 120
 121         if (router != neigh_node)
 122                 _batadv_update_route(bat_priv, orig_node, neigh_node);
 123
 124 out:
 125         if (router)
 126                 batadv_neigh_node_free_ref(router);
 127 }
 128
 129 /* caller must hold the neigh_list_lock */
 130 void batadv_bonding_candidate_del(struct batadv_orig_node *orig_node,
 131                                   struct batadv_neigh_node *neigh_node)
 132 {
 133         /* this neighbor is not part of our candidate list */
 134         if (list_empty(&neigh_node->bonding_list))
 135                 goto out;
 136
 137         list_del_rcu(&neigh_node->bonding_list);
 138         INIT_LIST_HEAD(&neigh_node->bonding_list);
 139         batadv_neigh_node_free_ref(neigh_node);
 140         atomic_dec(&orig_node->bond_candidates);
 141
 142 out:
 143         return;
 144 }
 145
 146 void batadv_bonding_candidate_add(struct batadv_orig_node *orig_node,
 147                                   struct batadv_neigh_node *neigh_node)
 148 {
 149         struct hlist_node *node;
 150         struct batadv_neigh_node *tmp_neigh_node, *router = NULL;
 151         uint8_t interference_candidate = 0;
 152
 153         spin_lock_bh(&orig_node->neigh_list_lock);
 154
 155         /* only consider if it has the same primary address ...  */
 156         if (!batadv_compare_eth(orig_node->orig,
 157                                 neigh_node->orig_node->primary_addr))
 158                 goto candidate_del;
 159
 160         router = batadv_orig_node_get_router(orig_node);
 161         if (!router)
 162                 goto candidate_del;
 163
 164         /* ... and is good enough to be considered */
 165         if (neigh_node->tq_avg < router->tq_avg - BATADV_BONDING_TQ_THRESHOLD)
 166                 goto candidate_del;
 167
 168         /* check if we have another candidate with the same mac address or
 169          * interface. If we do, we won't select this candidate because of
 170          * possible interference.
 171          */
 172         hlist_for_each_entry_rcu(tmp_neigh_node, node,
 173                                  &orig_node->neigh_list, list) {
 174                 if (tmp_neigh_node == neigh_node)
 175                         continue;
 176
 177                 /* we only care if the other candidate is even
 178                  * considered as candidate.
 179                  */
 180                 if (list_empty(&tmp_neigh_node->bonding_list))
 181                         continue;
 182
 183                 if ((neigh_node->if_incoming == tmp_neigh_node->if_incoming) ||
 184                     (batadv_compare_eth(neigh_node->addr,
 185                                         tmp_neigh_node->addr))) {
 186                         interference_candidate = 1;
 187                         break;
 188                 }
 189         }
 190
 191         /* don't care further if it is an interference candidate */
 192         if (interference_candidate)
 193                 goto candidate_del;
 194
 195         /* this neighbor already is part of our candidate list */
 196         if (!list_empty(&neigh_node->bonding_list))
 197                 goto out;
 198
 199         if (!atomic_inc_not_zero(&neigh_node->refcount))
 200                 goto out;
 201
 202         list_add_rcu(&neigh_node->bonding_list, &orig_node->bond_list);
 203         atomic_inc(&orig_node->bond_candidates);
 204         goto out;
 205
 206 candidate_del:
 207         batadv_bonding_candidate_del(orig_node, neigh_node);
 208
 209 out:
 210         spin_unlock_bh(&orig_node->neigh_list_lock);
 211
 212         if (router)
 213                 batadv_neigh_node_free_ref(router);
 214 }
 215
 216 /* copy primary address for bonding */
 217 void
 218 batadv_bonding_save_primary(const struct batadv_orig_node *orig_node,
 219                             struct batadv_orig_node *orig_neigh_node,
 220                             const struct batadv_ogm_packet *batman_ogm_packet)
 221 {
 222         if (!(batman_ogm_packet->flags & BATADV_PRIMARIES_FIRST_HOP))
 223                 return;
 224
 225         memcpy(orig_neigh_node->primary_addr, orig_node->orig, ETH_ALEN);
 226 }
 227
 228 /* checks whether the host restarted and is in the protection time.
 229  * returns:
 230  *  0 if the packet is to be accepted
 231  *  1 if the packet is to be ignored.
 232  */
 233 int batadv_window_protected(struct batadv_priv *bat_priv, int32_t seq_num_diff,
 234                             unsigned long *last_reset)
 235 {
 236         if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
 237             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 238                 if (!batadv_has_timed_out(*last_reset,
 239                                           BATADV_RESET_PROTECTION_MS))
 240                         return 1;
 241
 242                 *last_reset = jiffies;
 243                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 244                            "old packet received, start protection\n");
 245         }
 246
 247         return 0;
 248 }
 249
 250 bool batadv_check_management_packet(struct sk_buff *skb,
 251                                     struct batadv_hard_iface *hard_iface,
 252                                     int header_len)
 253 {
 254         struct ethhdr *ethhdr;
 255
 256         /* drop packet if it has not necessary minimum size */
 257         if (unlikely(!pskb_may_pull(skb, header_len)))
 258                 return false;
 259
 260         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 261
 262         /* packet with broadcast indication but unicast recipient */
 263         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 264                 return false;
 265
 266         /* packet with broadcast sender address */
 267         if (is_broadcast_ether_addr(ethhdr->h_source))
 268                 return false;
 269
 270         /* create a copy of the skb, if needed, to modify it. */
 271         if (skb_cow(skb, 0) < 0)
 272                 return false;
 273
 274         /* keep skb linear */
 275         if (skb_linearize(skb) < 0)
 276                 return false;
 277
 278         return true;
 279 }
 280
 281 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 282                                       struct sk_buff *skb, size_t icmp_len)
 283 {
 284         struct batadv_hard_iface *primary_if = NULL;
 285         struct batadv_orig_node *orig_node = NULL;
 286         struct batadv_icmp_packet_rr *icmp_packet;
 287         int ret = NET_RX_DROP;
 288
 289         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 290
 291         /* add data to device queue */
 292         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 293                 batadv_socket_receive_packet(icmp_packet, icmp_len);
 294                 goto out;
 295         }
 296
 297         primary_if = batadv_primary_if_get_selected(bat_priv);
 298         if (!primary_if)
 299                 goto out;
 300
 301         /* answer echo request (ping) */
 302         /* get routing information */
 303         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 304         if (!orig_node)
 305                 goto out;
 306
 307         /* create a copy of the skb, if needed, to modify it. */
 308         if (skb_cow(skb, ETH_HLEN) < 0)
 309                 goto out;
 310
 311         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 312
 313         memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
 314         memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 315         icmp_packet->msg_type = BATADV_ECHO_REPLY;
 316         icmp_packet->header.ttl = BATADV_TTL;
 317
 318         if (batadv_send_skb_to_orig(skb, orig_node, NULL))
 319                 ret = NET_RX_SUCCESS;
 320
 321 out:
 322         if (primary_if)
 323                 batadv_hardif_free_ref(primary_if);
 324         if (orig_node)
 325                 batadv_orig_node_free_ref(orig_node);
 326         return ret;
 327 }
 328
 329 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 330                                          struct sk_buff *skb)
 331 {
 332         struct batadv_hard_iface *primary_if = NULL;
 333         struct batadv_orig_node *orig_node = NULL;
 334         struct batadv_icmp_packet *icmp_packet;
 335         int ret = NET_RX_DROP;
 336
 337         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 338
 339         /* send TTL exceeded if packet is an echo request (traceroute) */
 340         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 341                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 342                          icmp_packet->orig, icmp_packet->dst);
 343                 goto out;
 344         }
 345
 346         primary_if = batadv_primary_if_get_selected(bat_priv);
 347         if (!primary_if)
 348                 goto out;
 349
 350         /* get routing information */
 351         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 352         if (!orig_node)
 353                 goto out;
 354
 355         /* create a copy of the skb, if needed, to modify it. */
 356         if (skb_cow(skb, ETH_HLEN) < 0)
 357                 goto out;
 358
 359         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 360
 361         memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
 362         memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 363         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 364         icmp_packet->header.ttl = BATADV_TTL;
 365
 366         if (batadv_send_skb_to_orig(skb, orig_node, NULL))
 367                 ret = NET_RX_SUCCESS;
 368
 369 out:
 370         if (primary_if)
 371                 batadv_hardif_free_ref(primary_if);
 372         if (orig_node)
 373                 batadv_orig_node_free_ref(orig_node);
 374         return ret;
 375 }
 376
 377
 378 int batadv_recv_icmp_packet(struct sk_buff *skb,
 379                             struct batadv_hard_iface *recv_if)
 380 {
 381         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 382         struct batadv_icmp_packet_rr *icmp_packet;
 383         struct ethhdr *ethhdr;
 384         struct batadv_orig_node *orig_node = NULL;
 385         int hdr_size = sizeof(struct batadv_icmp_packet);
 386         int ret = NET_RX_DROP;
 387
 388         /* we truncate all incoming icmp packets if they don't match our size */
 389         if (skb->len >= sizeof(struct batadv_icmp_packet_rr))
 390                 hdr_size = sizeof(struct batadv_icmp_packet_rr);
 391
 392         /* drop packet if it has not necessary minimum size */
 393         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 394                 goto out;
 395
 396         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 397
 398         /* packet with unicast indication but broadcast recipient */
 399         if (is_broadcast_ether_addr(ethhdr->h_dest))
 400                 goto out;
 401
 402         /* packet with broadcast sender address */
 403         if (is_broadcast_ether_addr(ethhdr->h_source))
 404                 goto out;
 405
 406         /* not for me */
 407         if (!batadv_is_my_mac(ethhdr->h_dest))
 408                 goto out;
 409
 410         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 411
 412         /* add record route information if not full */
 413         if ((hdr_size == sizeof(struct batadv_icmp_packet_rr)) &&
 414             (icmp_packet->rr_cur < BATADV_RR_LEN)) {
 415                 memcpy(&(icmp_packet->rr[icmp_packet->rr_cur]),
 416                        ethhdr->h_dest, ETH_ALEN);
 417                 icmp_packet->rr_cur++;
 418         }
 419
 420         /* packet for me */
 421         if (batadv_is_my_mac(icmp_packet->dst))
 422                 return batadv_recv_my_icmp_packet(bat_priv, skb, hdr_size);
 423
 424         /* TTL exceeded */
 425         if (icmp_packet->header.ttl < 2)
 426                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 427
 428         /* get routing information */
 429         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->dst);
 430         if (!orig_node)
 431                 goto out;
 432
 433         /* create a copy of the skb, if needed, to modify it. */
 434         if (skb_cow(skb, ETH_HLEN) < 0)
 435                 goto out;
 436
 437         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 438
 439         /* decrement ttl */
 440         icmp_packet->header.ttl--;
 441
 442         /* route it */
 443         if (batadv_send_skb_to_orig(skb, orig_node, recv_if))
 444                 ret = NET_RX_SUCCESS;
 445
 446 out:
 447         if (orig_node)
 448                 batadv_orig_node_free_ref(orig_node);
 449         return ret;
 450 }
 451
 452 /* In the bonding case, send the packets in a round
 453  * robin fashion over the remaining interfaces.
 454  *
 455  * This method rotates the bonding list and increases the
 456  * returned router's refcount.
 457  */
 458 static struct batadv_neigh_node *
 459 batadv_find_bond_router(struct batadv_orig_node *primary_orig,
 460                         const struct batadv_hard_iface *recv_if)
 461 {
 462         struct batadv_neigh_node *tmp_neigh_node;
 463         struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
 464
 465         rcu_read_lock();
 466         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 467                                 bonding_list) {
 468                 if (!first_candidate)
 469                         first_candidate = tmp_neigh_node;
 470
 471                 /* recv_if == NULL on the first node. */
 472                 if (tmp_neigh_node->if_incoming == recv_if)
 473                         continue;
 474
 475                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 476                         continue;
 477
 478                 router = tmp_neigh_node;
 479                 break;
 480         }
 481
 482         /* use the first candidate if nothing was found. */
 483         if (!router && first_candidate &&
 484             atomic_inc_not_zero(&first_candidate->refcount))
 485                 router = first_candidate;
 486
 487         if (!router)
 488                 goto out;
 489
 490         /* selected should point to the next element
 491          * after the current router
 492          */
 493         spin_lock_bh(&primary_orig->neigh_list_lock);
 494         /* this is a list_move(), which unfortunately
 495          * does not exist as rcu version
 496          */
 497         list_del_rcu(&primary_orig->bond_list);
 498         list_add_rcu(&primary_orig->bond_list,
 499                      &router->bonding_list);
 500         spin_unlock_bh(&primary_orig->neigh_list_lock);
 501
 502 out:
 503         rcu_read_unlock();
 504         return router;
 505 }
 506
 507 /* Interface Alternating: Use the best of the
 508  * remaining candidates which are not using
 509  * this interface.
 510  *
 511  * Increases the returned router's refcount
 512  */
 513 static struct batadv_neigh_node *
 514 batadv_find_ifalter_router(struct batadv_orig_node *primary_orig,
 515                            const struct batadv_hard_iface *recv_if)
 516 {
 517         struct batadv_neigh_node *tmp_neigh_node;
 518         struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
 519
 520         rcu_read_lock();
 521         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 522                                 bonding_list) {
 523                 if (!first_candidate)
 524                         first_candidate = tmp_neigh_node;
 525
 526                 /* recv_if == NULL on the first node. */
 527                 if (tmp_neigh_node->if_incoming == recv_if)
 528                         continue;
 529
 530                 if (router && tmp_neigh_node->tq_avg <= router->tq_avg)
 531                         continue;
 532
 533                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 534                         continue;
 535
 536                 /* decrement refcount of previously selected router */
 537                 if (router)
 538                         batadv_neigh_node_free_ref(router);
 539
 540                 /* we found a better router (or at least one valid router) */
 541                 router = tmp_neigh_node;
 542         }
 543
 544         /* use the first candidate if nothing was found. */
 545         if (!router && first_candidate &&
 546             atomic_inc_not_zero(&first_candidate->refcount))
 547                 router = first_candidate;
 548
 549         rcu_read_unlock();
 550         return router;
 551 }
 552
 553 static int batadv_check_unicast_packet(struct sk_buff *skb, int hdr_size)
 554 {
 555         struct ethhdr *ethhdr;
 556
 557         /* drop packet if it has not necessary minimum size */
 558         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 559                 return -1;
 560
 561         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 562
 563         /* packet with unicast indication but broadcast recipient */
 564         if (is_broadcast_ether_addr(ethhdr->h_dest))
 565                 return -1;
 566
 567         /* packet with broadcast sender address */
 568         if (is_broadcast_ether_addr(ethhdr->h_source))
 569                 return -1;
 570
 571         /* not for me */
 572         if (!batadv_is_my_mac(ethhdr->h_dest))
 573                 return -1;
 574
 575         return 0;
 576 }
 577
 578 int batadv_recv_tt_query(struct sk_buff *skb, struct batadv_hard_iface *recv_if)
 579 {
 580         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 581         struct batadv_tt_query_packet *tt_query;
 582         uint16_t tt_size;
 583         int hdr_size = sizeof(*tt_query);
 584         char tt_flag;
 585         size_t packet_size;
 586
 587         if (batadv_check_unicast_packet(skb, hdr_size) < 0)
 588                 return NET_RX_DROP;
 589
 590         /* I could need to modify it */
 591         if (skb_cow(skb, sizeof(struct batadv_tt_query_packet)) < 0)
 592                 goto out;
 593
 594         tt_query = (struct batadv_tt_query_packet *)skb->data;
 595
 596         switch (tt_query->flags & BATADV_TT_QUERY_TYPE_MASK) {
 597         case BATADV_TT_REQUEST:
 598                 batadv_inc_counter(bat_priv, BATADV_CNT_TT_REQUEST_RX);
 599
 600                 /* If we cannot provide an answer the tt_request is
 601                  * forwarded
 602                  */
 603                 if (!batadv_send_tt_response(bat_priv, tt_query)) {
 604                         if (tt_query->flags & BATADV_TT_FULL_TABLE)
 605                                 tt_flag = 'F';
 606                         else
 607                                 tt_flag = '.';
 608
 609                         batadv_dbg(BATADV_DBG_TT, bat_priv,
 610                                    "Routing TT_REQUEST to %pM [%c]\n",
 611                                    tt_query->dst,
 612                                    tt_flag);
 613                         return batadv_route_unicast_packet(skb, recv_if);
 614                 }
 615                 break;
 616         case BATADV_TT_RESPONSE:
 617                 batadv_inc_counter(bat_priv, BATADV_CNT_TT_RESPONSE_RX);
 618
 619                 if (batadv_is_my_mac(tt_query->dst)) {
 620                         /* packet needs to be linearized to access the TT
 621                          * changes
 622                          */
 623                         if (skb_linearize(skb) < 0)
 624                                 goto out;
 625                         /* skb_linearize() possibly changed skb->data */
 626                         tt_query = (struct batadv_tt_query_packet *)skb->data;
 627
 628                         tt_size = batadv_tt_len(ntohs(tt_query->tt_data));
 629
 630                         /* Ensure we have all the claimed data */
 631                         packet_size = sizeof(struct batadv_tt_query_packet);
 632                         packet_size += tt_size;
 633                         if (unlikely(skb_headlen(skb) < packet_size))
 634                                 goto out;
 635
 636                         batadv_handle_tt_response(bat_priv, tt_query);
 637                 } else {
 638                         if (tt_query->flags & BATADV_TT_FULL_TABLE)
 639                                 tt_flag =  'F';
 640                         else
 641                                 tt_flag = '.';
 642                         batadv_dbg(BATADV_DBG_TT, bat_priv,
 643                                    "Routing TT_RESPONSE to %pM [%c]\n",
 644                                    tt_query->dst,
 645                                    tt_flag);
 646                         return batadv_route_unicast_packet(skb, recv_if);
 647                 }
 648                 break;
 649         }
 650
 651 out:
 652         /* returning NET_RX_DROP will make the caller function kfree the skb */
 653         return NET_RX_DROP;
 654 }
 655
 656 int batadv_recv_roam_adv(struct sk_buff *skb, struct batadv_hard_iface *recv_if)
 657 {
 658         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 659         struct batadv_roam_adv_packet *roam_adv_packet;
 660         struct batadv_orig_node *orig_node;
 661
 662         if (batadv_check_unicast_packet(skb, sizeof(*roam_adv_packet)) < 0)
 663                 goto out;
 664
 665         batadv_inc_counter(bat_priv, BATADV_CNT_TT_ROAM_ADV_RX);
 666
 667         roam_adv_packet = (struct batadv_roam_adv_packet *)skb->data;
 668
 669         if (!batadv_is_my_mac(roam_adv_packet->dst))
 670                 return batadv_route_unicast_packet(skb, recv_if);
 671
 672         /* check if it is a backbone gateway. we don't accept
 673          * roaming advertisement from it, as it has the same
 674          * entries as we have.
 675          */
 676         if (batadv_bla_is_backbone_gw_orig(bat_priv, roam_adv_packet->src))
 677                 goto out;
 678
 679         orig_node = batadv_orig_hash_find(bat_priv, roam_adv_packet->src);
 680         if (!orig_node)
 681                 goto out;
 682
 683         batadv_dbg(BATADV_DBG_TT, bat_priv,
 684                    "Received ROAMING_ADV from %pM (client %pM)\n",
 685                    roam_adv_packet->src, roam_adv_packet->client);
 686
 687         batadv_tt_global_add(bat_priv, orig_node, roam_adv_packet->client,
 688                              BATADV_TT_CLIENT_ROAM,
 689                              atomic_read(&orig_node->last_ttvn) + 1);
 690
 691         batadv_orig_node_free_ref(orig_node);
 692 out:
 693         /* returning NET_RX_DROP will make the caller function kfree the skb */
 694         return NET_RX_DROP;
 695 }
 696
 697 /* find a suitable router for this originator, and use
 698  * bonding if possible. increases the found neighbors
 699  * refcount.
 700  */
 701 struct batadv_neigh_node *
 702 batadv_find_router(struct batadv_priv *bat_priv,
 703                    struct batadv_orig_node *orig_node,
 704                    const struct batadv_hard_iface *recv_if)
 705 {
 706         struct batadv_orig_node *primary_orig_node;
 707         struct batadv_orig_node *router_orig;
 708         struct batadv_neigh_node *router;
 709         static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
 710         int bonding_enabled;
 711         uint8_t *primary_addr;
 712
 713         if (!orig_node)
 714                 return NULL;
 715
 716         router = batadv_orig_node_get_router(orig_node);
 717         if (!router)
 718                 goto err;
 719
 720         /* without bonding, the first node should
 721          * always choose the default router.
 722          */
 723         bonding_enabled = atomic_read(&bat_priv->bonding);
 724
 725         rcu_read_lock();
 726         /* select default router to output */
 727         router_orig = router->orig_node;
 728         if (!router_orig)
 729                 goto err_unlock;
 730
 731         if ((!recv_if) && (!bonding_enabled))
 732                 goto return_router;
 733
 734         primary_addr = router_orig->primary_addr;
 735
 736         /* if we have something in the primary_addr, we can search
 737          * for a potential bonding candidate.
 738          */
 739         if (batadv_compare_eth(primary_addr, zero_mac))
 740                 goto return_router;
 741
 742         /* find the orig_node which has the primary interface. might
 743          * even be the same as our router_orig in many cases
 744          */
 745         if (batadv_compare_eth(primary_addr, router_orig->orig)) {
 746                 primary_orig_node = router_orig;
 747         } else {
 748                 primary_orig_node = batadv_orig_hash_find(bat_priv,
 749                                                           primary_addr);
 750                 if (!primary_orig_node)
 751                         goto return_router;
 752
 753                 batadv_orig_node_free_ref(primary_orig_node);
 754         }
 755
 756         /* with less than 2 candidates, we can't do any
 757          * bonding and prefer the original router.
 758          */
 759         if (atomic_read(&primary_orig_node->bond_candidates) < 2)
 760                 goto return_router;
 761
 762         /* all nodes between should choose a candidate which
 763          * is is not on the interface where the packet came
 764          * in.
 765          */
 766         batadv_neigh_node_free_ref(router);
 767
 768         if (bonding_enabled)
 769                 router = batadv_find_bond_router(primary_orig_node, recv_if);
 770         else
 771                 router = batadv_find_ifalter_router(primary_orig_node, recv_if);
 772
 773 return_router:
 774         if (router && router->if_incoming->if_status != BATADV_IF_ACTIVE)
 775                 goto err_unlock;
 776
 777         rcu_read_unlock();
 778         return router;
 779 err_unlock:
 780         rcu_read_unlock();
 781 err:
 782         if (router)
 783                 batadv_neigh_node_free_ref(router);
 784         return NULL;
 785 }
 786
 787 static int batadv_route_unicast_packet(struct sk_buff *skb,
 788                                        struct batadv_hard_iface *recv_if)
 789 {
 790         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 791         struct batadv_orig_node *orig_node = NULL;
 792         struct batadv_neigh_node *neigh_node = NULL;
 793         struct batadv_unicast_packet *unicast_packet;
 794         struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
 795         int ret = NET_RX_DROP;
 796         struct sk_buff *new_skb;
 797
 798         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 799
 800         /* TTL exceeded */
 801         if (unicast_packet->header.ttl < 2) {
 802                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 803                          ethhdr->h_source, unicast_packet->dest);
 804                 goto out;
 805         }
 806
 807         /* get routing information */
 808         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 809
 810         if (!orig_node)
 811                 goto out;
 812
 813         /* find_router() increases neigh_nodes refcount if found. */
 814         neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
 815
 816         if (!neigh_node)
 817                 goto out;
 818
 819         /* create a copy of the skb, if needed, to modify it. */
 820         if (skb_cow(skb, ETH_HLEN) < 0)
 821                 goto out;
 822
 823         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 824
 825         if (unicast_packet->header.packet_type == BATADV_UNICAST &&
 826             atomic_read(&bat_priv->fragmentation) &&
 827             skb->len > neigh_node->if_incoming->net_dev->mtu) {
 828                 ret = batadv_frag_send_skb(skb, bat_priv,
 829                                            neigh_node->if_incoming,
 830                                            neigh_node->addr);
 831                 goto out;
 832         }
 833
 834         if (unicast_packet->header.packet_type == BATADV_UNICAST_FRAG &&
 835             batadv_frag_can_reassemble(skb,
 836                                        neigh_node->if_incoming->net_dev->mtu)) {
 837                 ret = batadv_frag_reassemble_skb(skb, bat_priv, &new_skb);
 838
 839                 if (ret == NET_RX_DROP)
 840                         goto out;
 841
 842                 /* packet was buffered for late merge */
 843                 if (!new_skb) {
 844                         ret = NET_RX_SUCCESS;
 845                         goto out;
 846                 }
 847
 848                 skb = new_skb;
 849                 unicast_packet = (struct batadv_unicast_packet *)skb->data;
 850         }
 851
 852         /* decrement ttl */
 853         unicast_packet->header.ttl--;
 854
 855         /* Update stats counter */
 856         batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 857         batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 858                            skb->len + ETH_HLEN);
 859
 860         /* route it */
 861         if (batadv_send_skb_to_orig(skb, orig_node, recv_if))
 862                 ret = NET_RX_SUCCESS;
 863
 864 out:
 865         if (neigh_node)
 866                 batadv_neigh_node_free_ref(neigh_node);
 867         if (orig_node)
 868                 batadv_orig_node_free_ref(orig_node);
 869         return ret;
 870 }
 871
 872 /**
 873  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 874  * @bat_priv: the bat priv with all the soft interface information
 875  * @unicast_packet: the unicast header to be updated
 876  * @dst_addr: the payload destination
 877  *
 878  * Search the translation table for dst_addr and update the unicast header with
 879  * the new corresponding information (originator address where the destination
 880  * client currently is and its known TTVN)
 881  *
 882  * Returns true if the packet header has been updated, false otherwise
 883  */
 884 static bool
 885 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 886                               struct batadv_unicast_packet *unicast_packet,
 887                               uint8_t *dst_addr)
 888 {
 889         struct batadv_orig_node *orig_node = NULL;
 890         struct batadv_hard_iface *primary_if = NULL;
 891         bool ret = false;
 892         uint8_t *orig_addr, orig_ttvn;
 893
 894         if (batadv_is_my_client(bat_priv, dst_addr)) {
 895                 primary_if = batadv_primary_if_get_selected(bat_priv);
 896                 if (!primary_if)
 897                         goto out;
 898                 orig_addr = primary_if->net_dev->dev_addr;
 899                 orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 900         } else {
 901                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr);
 902                 if (!orig_node)
 903                         goto out;
 904
 905                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 906                         goto out;
 907
 908                 orig_addr = orig_node->orig;
 909                 orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 910         }
 911
 912         /* update the packet header */
 913         memcpy(unicast_packet->dest, orig_addr, ETH_ALEN);
 914         unicast_packet->ttvn = orig_ttvn;
 915
 916         ret = true;
 917 out:
 918         if (primary_if)
 919                 batadv_hardif_free_ref(primary_if);
 920         if (orig_node)
 921                 batadv_orig_node_free_ref(orig_node);
 922
 923         return ret;
 924 }
 925
 926 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 927                                      struct sk_buff *skb) {
 928         uint8_t curr_ttvn, old_ttvn;
 929         struct batadv_orig_node *orig_node;
 930         struct ethhdr *ethhdr;
 931         struct batadv_hard_iface *primary_if;
 932         struct batadv_unicast_packet *unicast_packet;
 933         int is_old_ttvn;
 934
 935         /* check if there is enough data before accessing it */
 936         if (pskb_may_pull(skb, sizeof(*unicast_packet) + ETH_HLEN) < 0)
 937                 return 0;
 938
 939         /* create a copy of the skb (in case of for re-routing) to modify it. */
 940         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 941                 return 0;
 942
 943         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 944         ethhdr = (struct ethhdr *)(skb->data + sizeof(*unicast_packet));
 945
 946         /* check if the destination client was served by this node and it is now
 947          * roaming. In this case, it means that the node has got a ROAM_ADV
 948          * message and that it knows the new destination in the mesh to re-route
 949          * the packet to
 950          */
 951         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest)) {
 952                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 953                                                   ethhdr->h_dest))
 954                         net_ratelimited_function(batadv_dbg, BATADV_DBG_TT,
 955                                                  bat_priv,
 956                                                  "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 957                                                  unicast_packet->dest,
 958                                                  ethhdr->h_dest);
 959                 /* at this point the mesh destination should have been
 960                  * substituted with the originator address found in the global
 961                  * table. If not, let the packet go untouched anyway because
 962                  * there is nothing the node can do
 963                  */
 964                 return 1;
 965         }
 966
 967         /* retrieve the TTVN known by this node for the packet destination. This
 968          * value is used later to check if the node which sent (or re-routed
 969          * last time) the packet had an updated information or not
 970          */
 971         curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 972         if (!batadv_is_my_mac(unicast_packet->dest)) {
 973                 orig_node = batadv_orig_hash_find(bat_priv,
 974                                                   unicast_packet->dest);
 975                 /* if it is not possible to find the orig_node representing the
 976                  * destination, the packet can immediately be dropped as it will
 977                  * not be possible to deliver it
 978                  */
 979                 if (!orig_node)
 980                         return 0;
 981
 982                 curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 983                 batadv_orig_node_free_ref(orig_node);
 984         }
 985
 986         /* check if the TTVN contained in the packet is fresher than what the
 987          * node knows
 988          */
 989         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 990         if (!is_old_ttvn)
 991                 return 1;
 992
 993         old_ttvn = unicast_packet->ttvn;
 994         /* the packet was forged based on outdated network information. Its
 995          * destination can possibly be updated and forwarded towards the new
 996          * target host
 997          */
 998         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 999                                           ethhdr->h_dest)) {
1000                 net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv,
1001                                          "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
1002                                          unicast_packet->dest, ethhdr->h_dest,
1003                                          old_ttvn, curr_ttvn);
1004                 return 1;
1005         }
1006
1007         /* the packet has not been re-routed: either the destination is
1008          * currently served by this node or there is no destination at all and
1009          * it is possible to drop the packet
1010          */
1011         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest))
1012                 return 0;
1013
1014         /* update the header in order to let the packet be delivered to this
1015          * node's soft interface
1016          */
1017         primary_if = batadv_primary_if_get_selected(bat_priv);
1018         if (!primary_if)
1019                 return 0;
1020
1021         memcpy(unicast_packet->dest, primary_if->net_dev->dev_addr, ETH_ALEN);
1022
1023         batadv_hardif_free_ref(primary_if);
1024
1025         unicast_packet->ttvn = curr_ttvn;
1026
1027         return 1;
1028 }
1029
1030 int batadv_recv_unicast_packet(struct sk_buff *skb,
1031                                struct batadv_hard_iface *recv_if)
1032 {
1033         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1034         struct batadv_unicast_packet *unicast_packet;
1035         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
1036         uint8_t *orig_addr;
1037         struct batadv_orig_node *orig_node = NULL;
1038         int hdr_size = sizeof(*unicast_packet);
1039         bool is4addr;
1040
1041         unicast_packet = (struct batadv_unicast_packet *)skb->data;
1042         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
1043
1044         is4addr = unicast_packet->header.packet_type == BATADV_UNICAST_4ADDR;
1045         /* the caller function should have already pulled 2 bytes */
1046         if (is4addr)
1047                 hdr_size = sizeof(*unicast_4addr_packet);
1048
1049         if (batadv_check_unicast_packet(skb, hdr_size) < 0)
1050                 return NET_RX_DROP;
1051
1052         if (!batadv_check_unicast_ttvn(bat_priv, skb))
1053                 return NET_RX_DROP;
1054
1055         /* packet for me */
1056         if (batadv_is_my_mac(unicast_packet->dest)) {
1057                 if (is4addr) {
1058                         batadv_dat_inc_counter(bat_priv,
1059                                                unicast_4addr_packet->subtype);
1060                         orig_addr = unicast_4addr_packet->src;
1061                         orig_node = batadv_orig_hash_find(bat_priv, orig_addr);
1062                 }
1063
1064                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
1065                                                           hdr_size))
1066                         goto rx_success;
1067                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
1068                                                         hdr_size))
1069                         goto rx_success;
1070
1071                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1072                                     orig_node);
1073
1074 rx_success:
1075                 if (orig_node)
1076                         batadv_orig_node_free_ref(orig_node);
1077
1078                 return NET_RX_SUCCESS;
1079         }
1080
1081         return batadv_route_unicast_packet(skb, recv_if);
1082 }
1083
1084 int batadv_recv_ucast_frag_packet(struct sk_buff *skb,
1085                                   struct batadv_hard_iface *recv_if)
1086 {
1087         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1088         struct batadv_unicast_frag_packet *unicast_packet;
1089         int hdr_size = sizeof(*unicast_packet);
1090         struct sk_buff *new_skb = NULL;
1091         int ret;
1092
1093         if (batadv_check_unicast_packet(skb, hdr_size) < 0)
1094                 return NET_RX_DROP;
1095
1096         if (!batadv_check_unicast_ttvn(bat_priv, skb))
1097                 return NET_RX_DROP;
1098
1099         unicast_packet = (struct batadv_unicast_frag_packet *)skb->data;
1100
1101         /* packet for me */
1102         if (batadv_is_my_mac(unicast_packet->dest)) {
1103                 ret = batadv_frag_reassemble_skb(skb, bat_priv, &new_skb);
1104
1105                 if (ret == NET_RX_DROP)
1106                         return NET_RX_DROP;
1107
1108                 /* packet was buffered for late merge */
1109                 if (!new_skb)
1110                         return NET_RX_SUCCESS;
1111
1112                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, new_skb,
1113                                                           hdr_size))
1114                         goto rx_success;
1115                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, new_skb,
1116                                                         hdr_size))
1117                         goto rx_success;
1118
1119                 batadv_interface_rx(recv_if->soft_iface, new_skb, recv_if,
1120                                     sizeof(struct batadv_unicast_packet), NULL);
1121
1122 rx_success:
1123                 return NET_RX_SUCCESS;
1124         }
1125
1126         return batadv_route_unicast_packet(skb, recv_if);
1127 }
1128
1129
1130 int batadv_recv_bcast_packet(struct sk_buff *skb,
1131                              struct batadv_hard_iface *recv_if)
1132 {
1133         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1134         struct batadv_orig_node *orig_node = NULL;
1135         struct batadv_bcast_packet *bcast_packet;
1136         struct ethhdr *ethhdr;
1137         int hdr_size = sizeof(*bcast_packet);
1138         int ret = NET_RX_DROP;
1139         int32_t seq_diff;
1140
1141         /* drop packet if it has not necessary minimum size */
1142         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1143                 goto out;
1144
1145         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1146
1147         /* packet with broadcast indication but unicast recipient */
1148         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1149                 goto out;
1150
1151         /* packet with broadcast sender address */
1152         if (is_broadcast_ether_addr(ethhdr->h_source))
1153                 goto out;
1154
1155         /* ignore broadcasts sent by myself */
1156         if (batadv_is_my_mac(ethhdr->h_source))
1157                 goto out;
1158
1159         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1160
1161         /* ignore broadcasts originated by myself */
1162         if (batadv_is_my_mac(bcast_packet->orig))
1163                 goto out;
1164
1165         if (bcast_packet->header.ttl < 2)
1166                 goto out;
1167
1168         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1169
1170         if (!orig_node)
1171                 goto out;
1172
1173         spin_lock_bh(&orig_node->bcast_seqno_lock);
1174
1175         /* check whether the packet is a duplicate */
1176         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1177                             ntohl(bcast_packet->seqno)))
1178                 goto spin_unlock;
1179
1180         seq_diff = ntohl(bcast_packet->seqno) - orig_node->last_bcast_seqno;
1181
1182         /* check whether the packet is old and the host just restarted. */
1183         if (batadv_window_protected(bat_priv, seq_diff,
1184                                     &orig_node->bcast_seqno_reset))
1185                 goto spin_unlock;
1186
1187         /* mark broadcast in flood history, update window position
1188          * if required.
1189          */
1190         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1191                 orig_node->last_bcast_seqno = ntohl(bcast_packet->seqno);
1192
1193         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1194
1195         /* check whether this has been sent by another originator before */
1196         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1197                 goto out;
1198
1199         /* rebroadcast packet */
1200         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1201
1202         /* don't hand the broadcast up if it is from an originator
1203          * from the same backbone.
1204          */
1205         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1206                 goto out;
1207
1208         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1209                 goto rx_success;
1210         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1211                 goto rx_success;
1212
1213         /* broadcast for me */
1214         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1215                             orig_node);
1216
1217 rx_success:
1218         ret = NET_RX_SUCCESS;
1219         goto out;
1220
1221 spin_unlock:
1222         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1223 out:
1224         if (orig_node)
1225                 batadv_orig_node_free_ref(orig_node);
1226         return ret;
1227 }
1228
1229 int batadv_recv_vis_packet(struct sk_buff *skb,
1230                            struct batadv_hard_iface *recv_if)
1231 {
1232         struct batadv_vis_packet *vis_packet;
1233         struct ethhdr *ethhdr;
1234         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1235         int hdr_size = sizeof(*vis_packet);
1236
1237         /* keep skb linear */
1238         if (skb_linearize(skb) < 0)
1239                 return NET_RX_DROP;
1240
1241         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1242                 return NET_RX_DROP;
1243
1244         vis_packet = (struct batadv_vis_packet *)skb->data;
1245         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1246
1247         /* not for me */
1248         if (!batadv_is_my_mac(ethhdr->h_dest))
1249                 return NET_RX_DROP;
1250
1251         /* ignore own packets */
1252         if (batadv_is_my_mac(vis_packet->vis_orig))
1253                 return NET_RX_DROP;
1254
1255         if (batadv_is_my_mac(vis_packet->sender_orig))
1256                 return NET_RX_DROP;
1257
1258         switch (vis_packet->vis_type) {
1259         case BATADV_VIS_TYPE_SERVER_SYNC:
1260                 batadv_receive_server_sync_packet(bat_priv, vis_packet,
1261                                                   skb_headlen(skb));
1262                 break;
1263
1264         case BATADV_VIS_TYPE_CLIENT_UPDATE:
1265                 batadv_receive_client_update_packet(bat_priv, vis_packet,
1266                                                     skb_headlen(skb));
1267                 break;
1268
1269         default:        /* ignore unknown packet */
1270                 break;
1271         }
1272
1273         /* We take a copy of the data in the packet, so we should
1274          * always free the skbuf.
1275          */
1276         return NET_RX_DROP;
1277 }