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