net/batman-adv/routing.c

   1 /*
   2  * Copyright (C) 2007-2012 B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner, Simon Wunderlich
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA
  19  *
  20  */
  21
  22 #include "main.h"
  23 #include "routing.h"
  24 #include "send.h"
  25 #include "soft-interface.h"
  26 #include "hard-interface.h"
  27 #include "icmp_socket.h"
  28 #include "translation-table.h"
  29 #include "originator.h"
  30 #include "vis.h"
  31 #include "unicast.h"
  32 #include "bridge_loop_avoidance.h"
  33
  34 static int route_unicast_packet(struct sk_buff *skb,
  35                                 struct hard_iface *recv_if);
  36
  37 void slide_own_bcast_window(struct hard_iface *hard_iface)
  38 {
  39         struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
  40         struct hashtable_t *hash = bat_priv->orig_hash;
  41         struct hlist_node *node;
  42         struct hlist_head *head;
  43         struct orig_node *orig_node;
  44         unsigned long *word;
  45         uint32_t i;
  46         size_t word_index;
  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 * NUM_WORDS;
  55                         word = &(orig_node->bcast_own[word_index]);
  56
  57                         batadv_bit_get_packet(bat_priv, word, 1, 0);
  58                         orig_node->bcast_own_sum[hard_iface->if_num] =
  59                                 bitmap_weight(word, TQ_LOCAL_WINDOW_SIZE);
  60                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
  61                 }
  62                 rcu_read_unlock();
  63         }
  64 }
  65
  66 static void _update_route(struct bat_priv *bat_priv,
  67                           struct orig_node *orig_node,
  68                           struct neigh_node *neigh_node)
  69 {
  70         struct neigh_node *curr_router;
  71
  72         curr_router = orig_node_get_router(orig_node);
  73
  74         /* route deleted */
  75         if ((curr_router) && (!neigh_node)) {
  76                 bat_dbg(DBG_ROUTES, bat_priv, "Deleting route towards: %pM\n",
  77                         orig_node->orig);
  78                 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
  84                 bat_dbg(DBG_ROUTES, bat_priv,
  85                         "Adding route towards: %pM (via %pM)\n",
  86                         orig_node->orig, neigh_node->addr);
  87         /* route changed */
  88         } else if (neigh_node && curr_router) {
  89                 bat_dbg(DBG_ROUTES, bat_priv,
  90                         "Changing route towards: %pM (now via %pM - was via %pM)\n",
  91                         orig_node->orig, neigh_node->addr,
  92                         curr_router->addr);
  93         }
  94
  95         if (curr_router)
  96                 neigh_node_free_ref(curr_router);
  97
  98         /* increase refcount of new best neighbor */
  99         if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
 100                 neigh_node = NULL;
 101
 102         spin_lock_bh(&orig_node->neigh_list_lock);
 103         rcu_assign_pointer(orig_node->router, neigh_node);
 104         spin_unlock_bh(&orig_node->neigh_list_lock);
 105
 106         /* decrease refcount of previous best neighbor */
 107         if (curr_router)
 108                 neigh_node_free_ref(curr_router);
 109 }
 110
 111 void update_route(struct bat_priv *bat_priv, struct orig_node *orig_node,
 112                   struct neigh_node *neigh_node)
 113 {
 114         struct neigh_node *router = NULL;
 115
 116         if (!orig_node)
 117                 goto out;
 118
 119         router = orig_node_get_router(orig_node);
 120
 121         if (router != neigh_node)
 122                 _update_route(bat_priv, orig_node, neigh_node);
 123
 124 out:
 125         if (router)
 126                 neigh_node_free_ref(router);
 127 }
 128
 129 /* caller must hold the neigh_list_lock */
 130 void bonding_candidate_del(struct orig_node *orig_node,
 131                            struct 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         neigh_node_free_ref(neigh_node);
 140         atomic_dec(&orig_node->bond_candidates);
 141
 142 out:
 143         return;
 144 }
 145
 146 void bonding_candidate_add(struct orig_node *orig_node,
 147                            struct neigh_node *neigh_node)
 148 {
 149         struct hlist_node *node;
 150         struct 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 (!compare_eth(orig_node->orig,
 157                          neigh_node->orig_node->primary_addr))
 158                 goto candidate_del;
 159
 160         router = 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 - BONDING_TQ_THRESHOLD)
 166                 goto candidate_del;
 167
 168         /**
 169          * check if we have another candidate with the same mac address or
 170          * interface. If we do, we won't select this candidate because of
 171          * possible interference.
 172          */
 173         hlist_for_each_entry_rcu(tmp_neigh_node, node,
 174                                  &orig_node->neigh_list, list) {
 175
 176                 if (tmp_neigh_node == neigh_node)
 177                         continue;
 178
 179                 /* we only care if the other candidate is even
 180                 * considered as candidate. */
 181                 if (list_empty(&tmp_neigh_node->bonding_list))
 182                         continue;
 183
 184                 if ((neigh_node->if_incoming == tmp_neigh_node->if_incoming) ||
 185                     (compare_eth(neigh_node->addr, 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         bonding_candidate_del(orig_node, neigh_node);
 208
 209 out:
 210         spin_unlock_bh(&orig_node->neigh_list_lock);
 211
 212         if (router)
 213                 neigh_node_free_ref(router);
 214 }
 215
 216 /* copy primary address for bonding */
 217 void bonding_save_primary(const struct orig_node *orig_node,
 218                           struct orig_node *orig_neigh_node,
 219                           const struct batman_ogm_packet *batman_ogm_packet)
 220 {
 221         if (!(batman_ogm_packet->flags & PRIMARIES_FIRST_HOP))
 222                 return;
 223
 224         memcpy(orig_neigh_node->primary_addr, orig_node->orig, ETH_ALEN);
 225 }
 226
 227 /* checks whether the host restarted and is in the protection time.
 228  * returns:
 229  *  0 if the packet is to be accepted
 230  *  1 if the packet is to be ignored.
 231  */
 232 int window_protected(struct bat_priv *bat_priv, int32_t seq_num_diff,
 233                      unsigned long *last_reset)
 234 {
 235         if ((seq_num_diff <= -TQ_LOCAL_WINDOW_SIZE) ||
 236             (seq_num_diff >= EXPECTED_SEQNO_RANGE)) {
 237                 if (!has_timed_out(*last_reset, RESET_PROTECTION_MS))
 238                         return 1;
 239
 240                 *last_reset = jiffies;
 241                 bat_dbg(DBG_BATMAN, bat_priv,
 242                         "old packet received, start protection\n");
 243         }
 244
 245         return 0;
 246 }
 247
 248 bool check_management_packet(struct sk_buff *skb,
 249                              struct 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 recv_my_icmp_packet(struct bat_priv *bat_priv,
 280                                struct sk_buff *skb, size_t icmp_len)
 281 {
 282         struct hard_iface *primary_if = NULL;
 283         struct orig_node *orig_node = NULL;
 284         struct neigh_node *router = NULL;
 285         struct icmp_packet_rr *icmp_packet;
 286         int ret = NET_RX_DROP;
 287
 288         icmp_packet = (struct icmp_packet_rr *)skb->data;
 289
 290         /* add data to device queue */
 291         if (icmp_packet->msg_type != ECHO_REQUEST) {
 292                 bat_socket_receive_packet(icmp_packet, icmp_len);
 293                 goto out;
 294         }
 295
 296         primary_if = primary_if_get_selected(bat_priv);
 297         if (!primary_if)
 298                 goto out;
 299
 300         /* answer echo request (ping) */
 301         /* get routing information */
 302         orig_node = orig_hash_find(bat_priv, icmp_packet->orig);
 303         if (!orig_node)
 304                 goto out;
 305
 306         router = orig_node_get_router(orig_node);
 307         if (!router)
 308                 goto out;
 309
 310         /* create a copy of the skb, if needed, to modify it. */
 311         if (skb_cow(skb, ETH_HLEN) < 0)
 312                 goto out;
 313
 314         icmp_packet = (struct icmp_packet_rr *)skb->data;
 315
 316         memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
 317         memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 318         icmp_packet->msg_type = ECHO_REPLY;
 319         icmp_packet->header.ttl = TTL;
 320
 321         send_skb_packet(skb, router->if_incoming, router->addr);
 322         ret = NET_RX_SUCCESS;
 323
 324 out:
 325         if (primary_if)
 326                 hardif_free_ref(primary_if);
 327         if (router)
 328                 neigh_node_free_ref(router);
 329         if (orig_node)
 330                 orig_node_free_ref(orig_node);
 331         return ret;
 332 }
 333
 334 static int recv_icmp_ttl_exceeded(struct bat_priv *bat_priv,
 335                                   struct sk_buff *skb)
 336 {
 337         struct hard_iface *primary_if = NULL;
 338         struct orig_node *orig_node = NULL;
 339         struct neigh_node *router = NULL;
 340         struct icmp_packet *icmp_packet;
 341         int ret = NET_RX_DROP;
 342
 343         icmp_packet = (struct icmp_packet *)skb->data;
 344
 345         /* send TTL exceeded if packet is an echo request (traceroute) */
 346         if (icmp_packet->msg_type != ECHO_REQUEST) {
 347                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 348                          icmp_packet->orig, icmp_packet->dst);
 349                 goto out;
 350         }
 351
 352         primary_if = primary_if_get_selected(bat_priv);
 353         if (!primary_if)
 354                 goto out;
 355
 356         /* get routing information */
 357         orig_node = orig_hash_find(bat_priv, icmp_packet->orig);
 358         if (!orig_node)
 359                 goto out;
 360
 361         router = orig_node_get_router(orig_node);
 362         if (!router)
 363                 goto out;
 364
 365         /* create a copy of the skb, if needed, to modify it. */
 366         if (skb_cow(skb, ETH_HLEN) < 0)
 367                 goto out;
 368
 369         icmp_packet = (struct icmp_packet *)skb->data;
 370
 371         memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
 372         memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 373         icmp_packet->msg_type = TTL_EXCEEDED;
 374         icmp_packet->header.ttl = TTL;
 375
 376         send_skb_packet(skb, router->if_incoming, router->addr);
 377         ret = NET_RX_SUCCESS;
 378
 379 out:
 380         if (primary_if)
 381                 hardif_free_ref(primary_if);
 382         if (router)
 383                 neigh_node_free_ref(router);
 384         if (orig_node)
 385                 orig_node_free_ref(orig_node);
 386         return ret;
 387 }
 388
 389
 390 int recv_icmp_packet(struct sk_buff *skb, struct hard_iface *recv_if)
 391 {
 392         struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 393         struct icmp_packet_rr *icmp_packet;
 394         struct ethhdr *ethhdr;
 395         struct orig_node *orig_node = NULL;
 396         struct neigh_node *router = NULL;
 397         int hdr_size = sizeof(struct icmp_packet);
 398         int ret = NET_RX_DROP;
 399
 400         /**
 401          * we truncate all incoming icmp packets if they don't match our size
 402          */
 403         if (skb->len >= sizeof(struct icmp_packet_rr))
 404                 hdr_size = sizeof(struct icmp_packet_rr);
 405
 406         /* drop packet if it has not necessary minimum size */
 407         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 408                 goto out;
 409
 410         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 411
 412         /* packet with unicast indication but broadcast recipient */
 413         if (is_broadcast_ether_addr(ethhdr->h_dest))
 414                 goto out;
 415
 416         /* packet with broadcast sender address */
 417         if (is_broadcast_ether_addr(ethhdr->h_source))
 418                 goto out;
 419
 420         /* not for me */
 421         if (!is_my_mac(ethhdr->h_dest))
 422                 goto out;
 423
 424         icmp_packet = (struct icmp_packet_rr *)skb->data;
 425
 426         /* add record route information if not full */
 427         if ((hdr_size == sizeof(struct icmp_packet_rr)) &&
 428             (icmp_packet->rr_cur < BAT_RR_LEN)) {
 429                 memcpy(&(icmp_packet->rr[icmp_packet->rr_cur]),
 430                        ethhdr->h_dest, ETH_ALEN);
 431                 icmp_packet->rr_cur++;
 432         }
 433
 434         /* packet for me */
 435         if (is_my_mac(icmp_packet->dst))
 436                 return recv_my_icmp_packet(bat_priv, skb, hdr_size);
 437
 438         /* TTL exceeded */
 439         if (icmp_packet->header.ttl < 2)
 440                 return recv_icmp_ttl_exceeded(bat_priv, skb);
 441
 442         /* get routing information */
 443         orig_node = orig_hash_find(bat_priv, icmp_packet->dst);
 444         if (!orig_node)
 445                 goto out;
 446
 447         router = orig_node_get_router(orig_node);
 448         if (!router)
 449                 goto out;
 450
 451         /* create a copy of the skb, if needed, to modify it. */
 452         if (skb_cow(skb, ETH_HLEN) < 0)
 453                 goto out;
 454
 455         icmp_packet = (struct icmp_packet_rr *)skb->data;
 456
 457         /* decrement ttl */
 458         icmp_packet->header.ttl--;
 459
 460         /* route it */
 461         send_skb_packet(skb, router->if_incoming, router->addr);
 462         ret = NET_RX_SUCCESS;
 463
 464 out:
 465         if (router)
 466                 neigh_node_free_ref(router);
 467         if (orig_node)
 468                 orig_node_free_ref(orig_node);
 469         return ret;
 470 }
 471
 472 /* In the bonding case, send the packets in a round
 473  * robin fashion over the remaining interfaces.
 474  *
 475  * This method rotates the bonding list and increases the
 476  * returned router's refcount. */
 477 static struct neigh_node *find_bond_router(struct orig_node *primary_orig,
 478                                            const struct hard_iface *recv_if)
 479 {
 480         struct neigh_node *tmp_neigh_node;
 481         struct neigh_node *router = NULL, *first_candidate = NULL;
 482
 483         rcu_read_lock();
 484         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 485                                 bonding_list) {
 486                 if (!first_candidate)
 487                         first_candidate = tmp_neigh_node;
 488
 489                 /* recv_if == NULL on the first node. */
 490                 if (tmp_neigh_node->if_incoming == recv_if)
 491                         continue;
 492
 493                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 494                         continue;
 495
 496                 router = tmp_neigh_node;
 497                 break;
 498         }
 499
 500         /* use the first candidate if nothing was found. */
 501         if (!router && first_candidate &&
 502             atomic_inc_not_zero(&first_candidate->refcount))
 503                 router = first_candidate;
 504
 505         if (!router)
 506                 goto out;
 507
 508         /* selected should point to the next element
 509          * after the current router */
 510         spin_lock_bh(&primary_orig->neigh_list_lock);
 511         /* this is a list_move(), which unfortunately
 512          * does not exist as rcu version */
 513         list_del_rcu(&primary_orig->bond_list);
 514         list_add_rcu(&primary_orig->bond_list,
 515                      &router->bonding_list);
 516         spin_unlock_bh(&primary_orig->neigh_list_lock);
 517
 518 out:
 519         rcu_read_unlock();
 520         return router;
 521 }
 522
 523 /* Interface Alternating: Use the best of the
 524  * remaining candidates which are not using
 525  * this interface.
 526  *
 527  * Increases the returned router's refcount */
 528 static struct neigh_node *find_ifalter_router(struct orig_node *primary_orig,
 529                                               const struct hard_iface *recv_if)
 530 {
 531         struct neigh_node *tmp_neigh_node;
 532         struct neigh_node *router = NULL, *first_candidate = NULL;
 533
 534         rcu_read_lock();
 535         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 536                                 bonding_list) {
 537                 if (!first_candidate)
 538                         first_candidate = tmp_neigh_node;
 539
 540                 /* recv_if == NULL on the first node. */
 541                 if (tmp_neigh_node->if_incoming == recv_if)
 542                         continue;
 543
 544                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 545                         continue;
 546
 547                 /* if we don't have a router yet
 548                  * or this one is better, choose it. */
 549                 if ((!router) ||
 550                     (tmp_neigh_node->tq_avg > router->tq_avg)) {
 551                         /* decrement refcount of
 552                          * previously selected router */
 553                         if (router)
 554                                 neigh_node_free_ref(router);
 555
 556                         router = tmp_neigh_node;
 557                         atomic_inc_not_zero(&router->refcount);
 558                 }
 559
 560                 neigh_node_free_ref(tmp_neigh_node);
 561         }
 562
 563         /* use the first candidate if nothing was found. */
 564         if (!router && first_candidate &&
 565             atomic_inc_not_zero(&first_candidate->refcount))
 566                 router = first_candidate;
 567
 568         rcu_read_unlock();
 569         return router;
 570 }
 571
 572 int recv_tt_query(struct sk_buff *skb, struct hard_iface *recv_if)
 573 {
 574         struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 575         struct tt_query_packet *tt_query;
 576         uint16_t tt_size;
 577         struct ethhdr *ethhdr;
 578
 579         /* drop packet if it has not necessary minimum size */
 580         if (unlikely(!pskb_may_pull(skb, sizeof(struct tt_query_packet))))
 581                 goto out;
 582
 583         /* I could need to modify it */
 584         if (skb_cow(skb, sizeof(struct tt_query_packet)) < 0)
 585                 goto out;
 586
 587         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 588
 589         /* packet with unicast indication but broadcast recipient */
 590         if (is_broadcast_ether_addr(ethhdr->h_dest))
 591                 goto out;
 592
 593         /* packet with broadcast sender address */
 594         if (is_broadcast_ether_addr(ethhdr->h_source))
 595                 goto out;
 596
 597         tt_query = (struct tt_query_packet *)skb->data;
 598
 599         switch (tt_query->flags & TT_QUERY_TYPE_MASK) {
 600         case TT_REQUEST:
 601                 batadv_inc_counter(bat_priv, BAT_CNT_TT_REQUEST_RX);
 602
 603                 /* If we cannot provide an answer the tt_request is
 604                  * forwarded */
 605                 if (!send_tt_response(bat_priv, tt_query)) {
 606                         bat_dbg(DBG_TT, bat_priv,
 607                                 "Routing TT_REQUEST to %pM [%c]\n",
 608                                 tt_query->dst,
 609                                 (tt_query->flags & TT_FULL_TABLE ? 'F' : '.'));
 610                         return route_unicast_packet(skb, recv_if);
 611                 }
 612                 break;
 613         case TT_RESPONSE:
 614                 batadv_inc_counter(bat_priv, BAT_CNT_TT_RESPONSE_RX);
 615
 616                 if (is_my_mac(tt_query->dst)) {
 617                         /* packet needs to be linearized to access the TT
 618                          * changes */
 619                         if (skb_linearize(skb) < 0)
 620                                 goto out;
 621                         /* skb_linearize() possibly changed skb->data */
 622                         tt_query = (struct tt_query_packet *)skb->data;
 623
 624                         tt_size = tt_len(ntohs(tt_query->tt_data));
 625
 626                         /* Ensure we have all the claimed data */
 627                         if (unlikely(skb_headlen(skb) <
 628                                      sizeof(struct tt_query_packet) + tt_size))
 629                                 goto out;
 630
 631                         handle_tt_response(bat_priv, tt_query);
 632                 } else {
 633                         bat_dbg(DBG_TT, bat_priv,
 634                                 "Routing TT_RESPONSE to %pM [%c]\n",
 635                                 tt_query->dst,
 636                                 (tt_query->flags & TT_FULL_TABLE ? 'F' : '.'));
 637                         return route_unicast_packet(skb, recv_if);
 638                 }
 639                 break;
 640         }
 641
 642 out:
 643         /* returning NET_RX_DROP will make the caller function kfree the skb */
 644         return NET_RX_DROP;
 645 }
 646
 647 int recv_roam_adv(struct sk_buff *skb, struct hard_iface *recv_if)
 648 {
 649         struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 650         struct roam_adv_packet *roam_adv_packet;
 651         struct orig_node *orig_node;
 652         struct ethhdr *ethhdr;
 653
 654         /* drop packet if it has not necessary minimum size */
 655         if (unlikely(!pskb_may_pull(skb, sizeof(struct roam_adv_packet))))
 656                 goto out;
 657
 658         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 659
 660         /* packet with unicast indication but broadcast recipient */
 661         if (is_broadcast_ether_addr(ethhdr->h_dest))
 662                 goto out;
 663
 664         /* packet with broadcast sender address */
 665         if (is_broadcast_ether_addr(ethhdr->h_source))
 666                 goto out;
 667
 668         batadv_inc_counter(bat_priv, BAT_CNT_TT_ROAM_ADV_RX);
 669
 670         roam_adv_packet = (struct roam_adv_packet *)skb->data;
 671
 672         if (!is_my_mac(roam_adv_packet->dst))
 673                 return route_unicast_packet(skb, recv_if);
 674
 675         /* check if it is a backbone gateway. we don't accept
 676          * roaming advertisement from it, as it has the same
 677          * entries as we have.
 678          */
 679         if (batadv_bla_is_backbone_gw_orig(bat_priv, roam_adv_packet->src))
 680                 goto out;
 681
 682         orig_node = orig_hash_find(bat_priv, roam_adv_packet->src);
 683         if (!orig_node)
 684                 goto out;
 685
 686         bat_dbg(DBG_TT, bat_priv,
 687                 "Received ROAMING_ADV from %pM (client %pM)\n",
 688                 roam_adv_packet->src, roam_adv_packet->client);
 689
 690         tt_global_add(bat_priv, orig_node, roam_adv_packet->client,
 691                       atomic_read(&orig_node->last_ttvn) + 1, true, false);
 692
 693         /* Roaming phase starts: I have new information but the ttvn has not
 694          * been incremented yet. This flag will make me check all the incoming
 695          * packets for the correct destination. */
 696         bat_priv->tt_poss_change = true;
 697
 698         orig_node_free_ref(orig_node);
 699 out:
 700         /* returning NET_RX_DROP will make the caller function kfree the skb */
 701         return NET_RX_DROP;
 702 }
 703
 704 /* find a suitable router for this originator, and use
 705  * bonding if possible. increases the found neighbors
 706  * refcount.*/
 707 struct neigh_node *find_router(struct bat_priv *bat_priv,
 708                                struct orig_node *orig_node,
 709                                const struct hard_iface *recv_if)
 710 {
 711         struct orig_node *primary_orig_node;
 712         struct orig_node *router_orig;
 713         struct neigh_node *router;
 714         static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
 715         int bonding_enabled;
 716
 717         if (!orig_node)
 718                 return NULL;
 719
 720         router = orig_node_get_router(orig_node);
 721         if (!router)
 722                 goto err;
 723
 724         /* without bonding, the first node should
 725          * always choose the default router. */
 726         bonding_enabled = atomic_read(&bat_priv->bonding);
 727
 728         rcu_read_lock();
 729         /* select default router to output */
 730         router_orig = router->orig_node;
 731         if (!router_orig)
 732                 goto err_unlock;
 733
 734         if ((!recv_if) && (!bonding_enabled))
 735                 goto return_router;
 736
 737         /* if we have something in the primary_addr, we can search
 738          * for a potential bonding candidate. */
 739         if (compare_eth(router_orig->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 (compare_eth(router_orig->primary_addr, router_orig->orig)) {
 746                 primary_orig_node = router_orig;
 747         } else {
 748                 primary_orig_node = orig_hash_find(bat_priv,
 749                                                    router_orig->primary_addr);
 750                 if (!primary_orig_node)
 751                         goto return_router;
 752
 753                 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         if (atomic_read(&primary_orig_node->bond_candidates) < 2)
 759                 goto return_router;
 760
 761         /* all nodes between should choose a candidate which
 762          * is is not on the interface where the packet came
 763          * in. */
 764
 765         neigh_node_free_ref(router);
 766
 767         if (bonding_enabled)
 768                 router = find_bond_router(primary_orig_node, recv_if);
 769         else
 770                 router = find_ifalter_router(primary_orig_node, recv_if);
 771
 772 return_router:
 773         if (router && router->if_incoming->if_status != IF_ACTIVE)
 774                 goto err_unlock;
 775
 776         rcu_read_unlock();
 777         return router;
 778 err_unlock:
 779         rcu_read_unlock();
 780 err:
 781         if (router)
 782                 neigh_node_free_ref(router);
 783         return NULL;
 784 }
 785
 786 static int check_unicast_packet(struct sk_buff *skb, int hdr_size)
 787 {
 788         struct ethhdr *ethhdr;
 789
 790         /* drop packet if it has not necessary minimum size */
 791         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 792                 return -1;
 793
 794         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 795
 796         /* packet with unicast indication but broadcast recipient */
 797         if (is_broadcast_ether_addr(ethhdr->h_dest))
 798                 return -1;
 799
 800         /* packet with broadcast sender address */
 801         if (is_broadcast_ether_addr(ethhdr->h_source))
 802                 return -1;
 803
 804         /* not for me */
 805         if (!is_my_mac(ethhdr->h_dest))
 806                 return -1;
 807
 808         return 0;
 809 }
 810
 811 static int route_unicast_packet(struct sk_buff *skb, struct hard_iface *recv_if)
 812 {
 813         struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 814         struct orig_node *orig_node = NULL;
 815         struct neigh_node *neigh_node = NULL;
 816         struct unicast_packet *unicast_packet;
 817         struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
 818         int ret = NET_RX_DROP;
 819         struct sk_buff *new_skb;
 820
 821         unicast_packet = (struct unicast_packet *)skb->data;
 822
 823         /* TTL exceeded */
 824         if (unicast_packet->header.ttl < 2) {
 825                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 826                          ethhdr->h_source, unicast_packet->dest);
 827                 goto out;
 828         }
 829
 830         /* get routing information */
 831         orig_node = orig_hash_find(bat_priv, unicast_packet->dest);
 832
 833         if (!orig_node)
 834                 goto out;
 835
 836         /* find_router() increases neigh_nodes refcount if found. */
 837         neigh_node = find_router(bat_priv, orig_node, recv_if);
 838
 839         if (!neigh_node)
 840                 goto out;
 841
 842         /* create a copy of the skb, if needed, to modify it. */
 843         if (skb_cow(skb, ETH_HLEN) < 0)
 844                 goto out;
 845
 846         unicast_packet = (struct unicast_packet *)skb->data;
 847
 848         if (unicast_packet->header.packet_type == BAT_UNICAST &&
 849             atomic_read(&bat_priv->fragmentation) &&
 850             skb->len > neigh_node->if_incoming->net_dev->mtu) {
 851                 ret = frag_send_skb(skb, bat_priv,
 852                                     neigh_node->if_incoming, neigh_node->addr);
 853                 goto out;
 854         }
 855
 856         if (unicast_packet->header.packet_type == BAT_UNICAST_FRAG &&
 857             frag_can_reassemble(skb, neigh_node->if_incoming->net_dev->mtu)) {
 858
 859                 ret = frag_reassemble_skb(skb, bat_priv, &new_skb);
 860
 861                 if (ret == NET_RX_DROP)
 862                         goto out;
 863
 864                 /* packet was buffered for late merge */
 865                 if (!new_skb) {
 866                         ret = NET_RX_SUCCESS;
 867                         goto out;
 868                 }
 869
 870                 skb = new_skb;
 871                 unicast_packet = (struct unicast_packet *)skb->data;
 872         }
 873
 874         /* decrement ttl */
 875         unicast_packet->header.ttl--;
 876
 877         /* Update stats counter */
 878         batadv_inc_counter(bat_priv, BAT_CNT_FORWARD);
 879         batadv_add_counter(bat_priv, BAT_CNT_FORWARD_BYTES,
 880                            skb->len + ETH_HLEN);
 881
 882         /* route it */
 883         send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
 884         ret = NET_RX_SUCCESS;
 885
 886 out:
 887         if (neigh_node)
 888                 neigh_node_free_ref(neigh_node);
 889         if (orig_node)
 890                 orig_node_free_ref(orig_node);
 891         return ret;
 892 }
 893
 894 static int check_unicast_ttvn(struct bat_priv *bat_priv,
 895                                struct sk_buff *skb) {
 896         uint8_t curr_ttvn;
 897         struct orig_node *orig_node;
 898         struct ethhdr *ethhdr;
 899         struct hard_iface *primary_if;
 900         struct unicast_packet *unicast_packet;
 901         bool tt_poss_change;
 902
 903         /* I could need to modify it */
 904         if (skb_cow(skb, sizeof(struct unicast_packet)) < 0)
 905                 return 0;
 906
 907         unicast_packet = (struct unicast_packet *)skb->data;
 908
 909         if (is_my_mac(unicast_packet->dest)) {
 910                 tt_poss_change = bat_priv->tt_poss_change;
 911                 curr_ttvn = (uint8_t)atomic_read(&bat_priv->ttvn);
 912         } else {
 913                 orig_node = orig_hash_find(bat_priv, unicast_packet->dest);
 914
 915                 if (!orig_node)
 916                         return 0;
 917
 918                 curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 919                 tt_poss_change = orig_node->tt_poss_change;
 920                 orig_node_free_ref(orig_node);
 921         }
 922
 923         /* Check whether I have to reroute the packet */
 924         if (seq_before(unicast_packet->ttvn, curr_ttvn) || tt_poss_change) {
 925                 /* check if there is enough data before accessing it */
 926                 if (pskb_may_pull(skb, sizeof(struct unicast_packet) +
 927                                   ETH_HLEN) < 0)
 928                         return 0;
 929
 930                 ethhdr = (struct ethhdr *)(skb->data +
 931                         sizeof(struct unicast_packet));
 932
 933                 /* we don't have an updated route for this client, so we should
 934                  * not try to reroute the packet!!
 935                  */
 936                 if (tt_global_client_is_roaming(bat_priv, ethhdr->h_dest))
 937                         return 1;
 938
 939                 orig_node = transtable_search(bat_priv, NULL, ethhdr->h_dest);
 940
 941                 if (!orig_node) {
 942                         if (!is_my_client(bat_priv, ethhdr->h_dest))
 943                                 return 0;
 944                         primary_if = primary_if_get_selected(bat_priv);
 945                         if (!primary_if)
 946                                 return 0;
 947                         memcpy(unicast_packet->dest,
 948                                primary_if->net_dev->dev_addr, ETH_ALEN);
 949                         hardif_free_ref(primary_if);
 950                 } else {
 951                         memcpy(unicast_packet->dest, orig_node->orig,
 952                                ETH_ALEN);
 953                         curr_ttvn = (uint8_t)
 954                                 atomic_read(&orig_node->last_ttvn);
 955                         orig_node_free_ref(orig_node);
 956                 }
 957
 958                 bat_dbg(DBG_ROUTES, bat_priv,
 959                         "TTVN mismatch (old_ttvn %u new_ttvn %u)! Rerouting unicast packet (for %pM) to %pM\n",
 960                         unicast_packet->ttvn, curr_ttvn, ethhdr->h_dest,
 961                         unicast_packet->dest);
 962
 963                 unicast_packet->ttvn = curr_ttvn;
 964         }
 965         return 1;
 966 }
 967
 968 int recv_unicast_packet(struct sk_buff *skb, struct hard_iface *recv_if)
 969 {
 970         struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 971         struct unicast_packet *unicast_packet;
 972         int hdr_size = sizeof(*unicast_packet);
 973
 974         if (check_unicast_packet(skb, hdr_size) < 0)
 975                 return NET_RX_DROP;
 976
 977         if (!check_unicast_ttvn(bat_priv, skb))
 978                 return NET_RX_DROP;
 979
 980         unicast_packet = (struct unicast_packet *)skb->data;
 981
 982         /* packet for me */
 983         if (is_my_mac(unicast_packet->dest)) {
 984                 interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size);
 985                 return NET_RX_SUCCESS;
 986         }
 987
 988         return route_unicast_packet(skb, recv_if);
 989 }
 990
 991 int recv_ucast_frag_packet(struct sk_buff *skb, struct hard_iface *recv_if)
 992 {
 993         struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 994         struct unicast_frag_packet *unicast_packet;
 995         int hdr_size = sizeof(*unicast_packet);
 996         struct sk_buff *new_skb = NULL;
 997         int ret;
 998
 999         if (check_unicast_packet(skb, hdr_size) < 0)
1000                 return NET_RX_DROP;
1001
1002         if (!check_unicast_ttvn(bat_priv, skb))
1003                 return NET_RX_DROP;
1004
1005         unicast_packet = (struct unicast_frag_packet *)skb->data;
1006
1007         /* packet for me */
1008         if (is_my_mac(unicast_packet->dest)) {
1009
1010                 ret = frag_reassemble_skb(skb, bat_priv, &new_skb);
1011
1012                 if (ret == NET_RX_DROP)
1013                         return NET_RX_DROP;
1014
1015                 /* packet was buffered for late merge */
1016                 if (!new_skb)
1017                         return NET_RX_SUCCESS;
1018
1019                 interface_rx(recv_if->soft_iface, new_skb, recv_if,
1020                              sizeof(struct unicast_packet));
1021                 return NET_RX_SUCCESS;
1022         }
1023
1024         return route_unicast_packet(skb, recv_if);
1025 }
1026
1027
1028 int recv_bcast_packet(struct sk_buff *skb, struct hard_iface *recv_if)
1029 {
1030         struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1031         struct orig_node *orig_node = NULL;
1032         struct bcast_packet *bcast_packet;
1033         struct ethhdr *ethhdr;
1034         int hdr_size = sizeof(*bcast_packet);
1035         int ret = NET_RX_DROP;
1036         int32_t seq_diff;
1037
1038         /* drop packet if it has not necessary minimum size */
1039         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1040                 goto out;
1041
1042         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1043
1044         /* packet with broadcast indication but unicast recipient */
1045         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1046                 goto out;
1047
1048         /* packet with broadcast sender address */
1049         if (is_broadcast_ether_addr(ethhdr->h_source))
1050                 goto out;
1051
1052         /* ignore broadcasts sent by myself */
1053         if (is_my_mac(ethhdr->h_source))
1054                 goto out;
1055
1056         bcast_packet = (struct bcast_packet *)skb->data;
1057
1058         /* ignore broadcasts originated by myself */
1059         if (is_my_mac(bcast_packet->orig))
1060                 goto out;
1061
1062         if (bcast_packet->header.ttl < 2)
1063                 goto out;
1064
1065         orig_node = orig_hash_find(bat_priv, bcast_packet->orig);
1066
1067         if (!orig_node)
1068                 goto out;
1069
1070         spin_lock_bh(&orig_node->bcast_seqno_lock);
1071
1072         /* check whether the packet is a duplicate */
1073         if (bat_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1074                          ntohl(bcast_packet->seqno)))
1075                 goto spin_unlock;
1076
1077         seq_diff = ntohl(bcast_packet->seqno) - orig_node->last_bcast_seqno;
1078
1079         /* check whether the packet is old and the host just restarted. */
1080         if (window_protected(bat_priv, seq_diff,
1081                              &orig_node->bcast_seqno_reset))
1082                 goto spin_unlock;
1083
1084         /* mark broadcast in flood history, update window position
1085          * if required. */
1086         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1087                 orig_node->last_bcast_seqno = ntohl(bcast_packet->seqno);
1088
1089         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1090
1091         /* check whether this has been sent by another originator before */
1092         if (batadv_bla_check_bcast_duplist(bat_priv, bcast_packet, hdr_size))
1093                 goto out;
1094
1095         /* rebroadcast packet */
1096         add_bcast_packet_to_list(bat_priv, skb, 1);
1097
1098         /* don't hand the broadcast up if it is from an originator
1099          * from the same backbone.
1100          */
1101         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1102                 goto out;
1103
1104         /* broadcast for me */
1105         interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size);
1106         ret = NET_RX_SUCCESS;
1107         goto out;
1108
1109 spin_unlock:
1110         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1111 out:
1112         if (orig_node)
1113                 orig_node_free_ref(orig_node);
1114         return ret;
1115 }
1116
1117 int recv_vis_packet(struct sk_buff *skb, struct hard_iface *recv_if)
1118 {
1119         struct vis_packet *vis_packet;
1120         struct ethhdr *ethhdr;
1121         struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1122         int hdr_size = sizeof(*vis_packet);
1123
1124         /* keep skb linear */
1125         if (skb_linearize(skb) < 0)
1126                 return NET_RX_DROP;
1127
1128         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1129                 return NET_RX_DROP;
1130
1131         vis_packet = (struct vis_packet *)skb->data;
1132         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1133
1134         /* not for me */
1135         if (!is_my_mac(ethhdr->h_dest))
1136                 return NET_RX_DROP;
1137
1138         /* ignore own packets */
1139         if (is_my_mac(vis_packet->vis_orig))
1140                 return NET_RX_DROP;
1141
1142         if (is_my_mac(vis_packet->sender_orig))
1143                 return NET_RX_DROP;
1144
1145         switch (vis_packet->vis_type) {
1146         case VIS_TYPE_SERVER_SYNC:
1147                 receive_server_sync_packet(bat_priv, vis_packet,
1148                                            skb_headlen(skb));
1149                 break;
1150
1151         case VIS_TYPE_CLIENT_UPDATE:
1152                 receive_client_update_packet(bat_priv, vis_packet,
1153                                              skb_headlen(skb));
1154                 break;
1155
1156         default:        /* ignore unknown packet */
1157                 break;
1158         }
1159
1160         /* We take a copy of the data in the packet, so we should
1161            always free the skbuf. */
1162         return NET_RX_DROP;
1163 }