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, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "main.h"
  19 #include "routing.h"
  20 #include "send.h"
  21 #include "soft-interface.h"
  22 #include "hard-interface.h"
  23 #include "icmp_socket.h"
  24 #include "translation-table.h"
  25 #include "originator.h"
  26 #include "bridge_loop_avoidance.h"
  27 #include "distributed-arp-table.h"
  28 #include "network-coding.h"
  29 #include "fragmentation.h"
  30
  31 #include <linux/if_vlan.h>
  32
  33 static int batadv_route_unicast_packet(struct sk_buff *skb,
  34                                        struct batadv_hard_iface *recv_if);
  35
  36 static void _batadv_update_route(struct batadv_priv *bat_priv,
  37                                  struct batadv_orig_node *orig_node,
  38                                  struct batadv_neigh_node *neigh_node)
  39 {
  40         struct batadv_neigh_node *curr_router;
  41
  42         curr_router = batadv_orig_node_get_router(orig_node);
  43
  44         /* route deleted */
  45         if ((curr_router) && (!neigh_node)) {
  46                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  47                            "Deleting route towards: %pM\n", orig_node->orig);
  48                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
  49                                           "Deleted route towards originator");
  50
  51         /* route added */
  52         } else if ((!curr_router) && (neigh_node)) {
  53                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  54                            "Adding route towards: %pM (via %pM)\n",
  55                            orig_node->orig, neigh_node->addr);
  56         /* route changed */
  57         } else if (neigh_node && curr_router) {
  58                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  59                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
  60                            orig_node->orig, neigh_node->addr,
  61                            curr_router->addr);
  62         }
  63
  64         if (curr_router)
  65                 batadv_neigh_node_free_ref(curr_router);
  66
  67         /* increase refcount of new best neighbor */
  68         if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
  69                 neigh_node = NULL;
  70
  71         spin_lock_bh(&orig_node->neigh_list_lock);
  72         rcu_assign_pointer(orig_node->router, neigh_node);
  73         spin_unlock_bh(&orig_node->neigh_list_lock);
  74
  75         /* decrease refcount of previous best neighbor */
  76         if (curr_router)
  77                 batadv_neigh_node_free_ref(curr_router);
  78 }
  79
  80 void batadv_update_route(struct batadv_priv *bat_priv,
  81                          struct batadv_orig_node *orig_node,
  82                          struct batadv_neigh_node *neigh_node)
  83 {
  84         struct batadv_neigh_node *router = NULL;
  85
  86         if (!orig_node)
  87                 goto out;
  88
  89         router = batadv_orig_node_get_router(orig_node);
  90
  91         if (router != neigh_node)
  92                 _batadv_update_route(bat_priv, orig_node, neigh_node);
  93
  94 out:
  95         if (router)
  96                 batadv_neigh_node_free_ref(router);
  97 }
  98
  99 /* caller must hold the neigh_list_lock */
 100 void batadv_bonding_candidate_del(struct batadv_orig_node *orig_node,
 101                                   struct batadv_neigh_node *neigh_node)
 102 {
 103         /* this neighbor is not part of our candidate list */
 104         if (list_empty(&neigh_node->bonding_list))
 105                 goto out;
 106
 107         list_del_rcu(&neigh_node->bonding_list);
 108         INIT_LIST_HEAD(&neigh_node->bonding_list);
 109         batadv_neigh_node_free_ref(neigh_node);
 110         atomic_dec(&orig_node->bond_candidates);
 111
 112 out:
 113         return;
 114 }
 115
 116 /**
 117  * batadv_bonding_candidate_add - consider a new link for bonding mode towards
 118  *  the given originator
 119  * @bat_priv: the bat priv with all the soft interface information
 120  * @orig_node: the target node
 121  * @neigh_node: the neighbor representing the new link to consider for bonding
 122  *  mode
 123  */
 124 void batadv_bonding_candidate_add(struct batadv_priv *bat_priv,
 125                                   struct batadv_orig_node *orig_node,
 126                                   struct batadv_neigh_node *neigh_node)
 127 {
 128         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 129         struct batadv_neigh_node *tmp_neigh_node, *router = NULL;
 130         uint8_t interference_candidate = 0;
 131
 132         spin_lock_bh(&orig_node->neigh_list_lock);
 133
 134         /* only consider if it has the same primary address ...  */
 135         if (!batadv_compare_eth(orig_node->orig,
 136                                 neigh_node->orig_node->primary_addr))
 137                 goto candidate_del;
 138
 139         router = batadv_orig_node_get_router(orig_node);
 140         if (!router)
 141                 goto candidate_del;
 142
 143
 144         /* ... and is good enough to be considered */
 145         if (bao->bat_neigh_is_equiv_or_better(neigh_node, router))
 146                 goto candidate_del;
 147
 148         /* check if we have another candidate with the same mac address or
 149          * interface. If we do, we won't select this candidate because of
 150          * possible interference.
 151          */
 152         hlist_for_each_entry_rcu(tmp_neigh_node,
 153                                  &orig_node->neigh_list, list) {
 154                 if (tmp_neigh_node == neigh_node)
 155                         continue;
 156
 157                 /* we only care if the other candidate is even
 158                  * considered as candidate.
 159                  */
 160                 if (list_empty(&tmp_neigh_node->bonding_list))
 161                         continue;
 162
 163                 if ((neigh_node->if_incoming == tmp_neigh_node->if_incoming) ||
 164                     (batadv_compare_eth(neigh_node->addr,
 165                                         tmp_neigh_node->addr))) {
 166                         interference_candidate = 1;
 167                         break;
 168                 }
 169         }
 170
 171         /* don't care further if it is an interference candidate */
 172         if (interference_candidate)
 173                 goto candidate_del;
 174
 175         /* this neighbor already is part of our candidate list */
 176         if (!list_empty(&neigh_node->bonding_list))
 177                 goto out;
 178
 179         if (!atomic_inc_not_zero(&neigh_node->refcount))
 180                 goto out;
 181
 182         list_add_rcu(&neigh_node->bonding_list, &orig_node->bond_list);
 183         atomic_inc(&orig_node->bond_candidates);
 184         goto out;
 185
 186 candidate_del:
 187         batadv_bonding_candidate_del(orig_node, neigh_node);
 188
 189 out:
 190         spin_unlock_bh(&orig_node->neigh_list_lock);
 191
 192         if (router)
 193                 batadv_neigh_node_free_ref(router);
 194 }
 195
 196 /* copy primary address for bonding */
 197 void
 198 batadv_bonding_save_primary(const struct batadv_orig_node *orig_node,
 199                             struct batadv_orig_node *orig_neigh_node,
 200                             const struct batadv_ogm_packet *batman_ogm_packet)
 201 {
 202         if (!(batman_ogm_packet->flags & BATADV_PRIMARIES_FIRST_HOP))
 203                 return;
 204
 205         memcpy(orig_neigh_node->primary_addr, orig_node->orig, ETH_ALEN);
 206 }
 207
 208 /* checks whether the host restarted and is in the protection time.
 209  * returns:
 210  *  0 if the packet is to be accepted
 211  *  1 if the packet is to be ignored.
 212  */
 213 int batadv_window_protected(struct batadv_priv *bat_priv, int32_t seq_num_diff,
 214                             unsigned long *last_reset)
 215 {
 216         if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
 217             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 218                 if (!batadv_has_timed_out(*last_reset,
 219                                           BATADV_RESET_PROTECTION_MS))
 220                         return 1;
 221
 222                 *last_reset = jiffies;
 223                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 224                            "old packet received, start protection\n");
 225         }
 226
 227         return 0;
 228 }
 229
 230 bool batadv_check_management_packet(struct sk_buff *skb,
 231                                     struct batadv_hard_iface *hard_iface,
 232                                     int header_len)
 233 {
 234         struct ethhdr *ethhdr;
 235
 236         /* drop packet if it has not necessary minimum size */
 237         if (unlikely(!pskb_may_pull(skb, header_len)))
 238                 return false;
 239
 240         ethhdr = eth_hdr(skb);
 241
 242         /* packet with broadcast indication but unicast recipient */
 243         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 244                 return false;
 245
 246         /* packet with broadcast sender address */
 247         if (is_broadcast_ether_addr(ethhdr->h_source))
 248                 return false;
 249
 250         /* create a copy of the skb, if needed, to modify it. */
 251         if (skb_cow(skb, 0) < 0)
 252                 return false;
 253
 254         /* keep skb linear */
 255         if (skb_linearize(skb) < 0)
 256                 return false;
 257
 258         return true;
 259 }
 260
 261 /**
 262  * batadv_recv_my_icmp_packet - receive an icmp packet locally
 263  * @bat_priv: the bat priv with all the soft interface information
 264  * @skb: icmp packet to process
 265  *
 266  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 267  * otherwise.
 268  */
 269 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 270                                       struct sk_buff *skb)
 271 {
 272         struct batadv_hard_iface *primary_if = NULL;
 273         struct batadv_orig_node *orig_node = NULL;
 274         struct batadv_icmp_header *icmph;
 275         int res, ret = NET_RX_DROP;
 276
 277         icmph = (struct batadv_icmp_header *)skb->data;
 278
 279         switch (icmph->msg_type) {
 280         case BATADV_ECHO_REPLY:
 281         case BATADV_DESTINATION_UNREACHABLE:
 282         case BATADV_TTL_EXCEEDED:
 283                 /* receive the packet */
 284                 if (skb_linearize(skb) < 0)
 285                         break;
 286
 287                 batadv_socket_receive_packet(icmph, skb->len);
 288                 break;
 289         case BATADV_ECHO_REQUEST:
 290                 /* answer echo request (ping) */
 291                 primary_if = batadv_primary_if_get_selected(bat_priv);
 292                 if (!primary_if)
 293                         goto out;
 294
 295                 /* get routing information */
 296                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 297                 if (!orig_node)
 298                         goto out;
 299
 300                 /* create a copy of the skb, if needed, to modify it. */
 301                 if (skb_cow(skb, ETH_HLEN) < 0)
 302                         goto out;
 303
 304                 icmph = (struct batadv_icmp_header *)skb->data;
 305
 306                 memcpy(icmph->dst, icmph->orig, ETH_ALEN);
 307                 memcpy(icmph->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 308                 icmph->msg_type = BATADV_ECHO_REPLY;
 309                 icmph->ttl = BATADV_TTL;
 310
 311                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 312                 if (res != NET_XMIT_DROP)
 313                         ret = NET_RX_SUCCESS;
 314
 315                 break;
 316         default:
 317                 /* drop unknown type */
 318                 goto out;
 319         }
 320 out:
 321         if (primary_if)
 322                 batadv_hardif_free_ref(primary_if);
 323         if (orig_node)
 324                 batadv_orig_node_free_ref(orig_node);
 325         return ret;
 326 }
 327
 328 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 329                                          struct sk_buff *skb)
 330 {
 331         struct batadv_hard_iface *primary_if = NULL;
 332         struct batadv_orig_node *orig_node = NULL;
 333         struct batadv_icmp_packet *icmp_packet;
 334         int ret = NET_RX_DROP;
 335
 336         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 337
 338         /* send TTL exceeded if packet is an echo request (traceroute) */
 339         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 340                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 341                          icmp_packet->orig, icmp_packet->dst);
 342                 goto out;
 343         }
 344
 345         primary_if = batadv_primary_if_get_selected(bat_priv);
 346         if (!primary_if)
 347                 goto out;
 348
 349         /* get routing information */
 350         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 351         if (!orig_node)
 352                 goto out;
 353
 354         /* create a copy of the skb, if needed, to modify it. */
 355         if (skb_cow(skb, ETH_HLEN) < 0)
 356                 goto out;
 357
 358         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 359
 360         memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
 361         memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr,
 362                ETH_ALEN);
 363         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 364         icmp_packet->ttl = BATADV_TTL;
 365
 366         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 367                 ret = NET_RX_SUCCESS;
 368
 369 out:
 370         if (primary_if)
 371                 batadv_hardif_free_ref(primary_if);
 372         if (orig_node)
 373                 batadv_orig_node_free_ref(orig_node);
 374         return ret;
 375 }
 376
 377
 378 int batadv_recv_icmp_packet(struct sk_buff *skb,
 379                             struct batadv_hard_iface *recv_if)
 380 {
 381         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 382         struct batadv_icmp_header *icmph;
 383         struct batadv_icmp_packet_rr *icmp_packet_rr;
 384         struct ethhdr *ethhdr;
 385         struct batadv_orig_node *orig_node = NULL;
 386         int hdr_size = sizeof(struct batadv_icmp_header);
 387         int ret = NET_RX_DROP;
 388
 389         /* drop packet if it has not necessary minimum size */
 390         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 391                 goto out;
 392
 393         ethhdr = eth_hdr(skb);
 394
 395         /* packet with unicast indication but broadcast recipient */
 396         if (is_broadcast_ether_addr(ethhdr->h_dest))
 397                 goto out;
 398
 399         /* packet with broadcast sender address */
 400         if (is_broadcast_ether_addr(ethhdr->h_source))
 401                 goto out;
 402
 403         /* not for me */
 404         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 405                 goto out;
 406
 407         icmph = (struct batadv_icmp_header *)skb->data;
 408
 409         /* add record route information if not full */
 410         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 411              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 412             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 413                 if (skb_linearize(skb) < 0)
 414                         goto out;
 415
 416                 /* create a copy of the skb, if needed, to modify it. */
 417                 if (skb_cow(skb, ETH_HLEN) < 0)
 418                         goto out;
 419
 420                 icmph = (struct batadv_icmp_header *)skb->data;
 421                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 422                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 423                         goto out;
 424
 425                 memcpy(&(icmp_packet_rr->rr[icmp_packet_rr->rr_cur]),
 426                        ethhdr->h_dest, ETH_ALEN);
 427                 icmp_packet_rr->rr_cur++;
 428         }
 429
 430         /* packet for me */
 431         if (batadv_is_my_mac(bat_priv, icmph->dst))
 432                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 433
 434         /* TTL exceeded */
 435         if (icmph->ttl < 2)
 436                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 437
 438         /* get routing information */
 439         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 440         if (!orig_node)
 441                 goto out;
 442
 443         /* create a copy of the skb, if needed, to modify it. */
 444         if (skb_cow(skb, ETH_HLEN) < 0)
 445                 goto out;
 446
 447         icmph = (struct batadv_icmp_header *)skb->data;
 448
 449         /* decrement ttl */
 450         icmph->ttl--;
 451
 452         /* route it */
 453         if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
 454                 ret = NET_RX_SUCCESS;
 455
 456 out:
 457         if (orig_node)
 458                 batadv_orig_node_free_ref(orig_node);
 459         return ret;
 460 }
 461
 462 /* In the bonding case, send the packets in a round
 463  * robin fashion over the remaining interfaces.
 464  *
 465  * This method rotates the bonding list and increases the
 466  * returned router's refcount.
 467  */
 468 static struct batadv_neigh_node *
 469 batadv_find_bond_router(struct batadv_orig_node *primary_orig,
 470                         const struct batadv_hard_iface *recv_if)
 471 {
 472         struct batadv_neigh_node *tmp_neigh_node;
 473         struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
 474
 475         rcu_read_lock();
 476         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 477                                 bonding_list) {
 478                 if (!first_candidate)
 479                         first_candidate = tmp_neigh_node;
 480
 481                 /* recv_if == NULL on the first node. */
 482                 if (tmp_neigh_node->if_incoming == recv_if)
 483                         continue;
 484
 485                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 486                         continue;
 487
 488                 router = tmp_neigh_node;
 489                 break;
 490         }
 491
 492         /* use the first candidate if nothing was found. */
 493         if (!router && first_candidate &&
 494             atomic_inc_not_zero(&first_candidate->refcount))
 495                 router = first_candidate;
 496
 497         if (!router)
 498                 goto out;
 499
 500         /* selected should point to the next element
 501          * after the current router
 502          */
 503         spin_lock_bh(&primary_orig->neigh_list_lock);
 504         /* this is a list_move(), which unfortunately
 505          * does not exist as rcu version
 506          */
 507         list_del_rcu(&primary_orig->bond_list);
 508         list_add_rcu(&primary_orig->bond_list,
 509                      &router->bonding_list);
 510         spin_unlock_bh(&primary_orig->neigh_list_lock);
 511
 512 out:
 513         rcu_read_unlock();
 514         return router;
 515 }
 516
 517 /**
 518  * batadv_find_ifalter_router - find the best of the remaining candidates which
 519  *  are not using this interface
 520  * @bat_priv: the bat priv with all the soft interface information
 521  * @primary_orig: the destination
 522  * @recv_if: the interface that the router returned by this function has to not
 523  *  use
 524  *
 525  * Returns the best candidate towards primary_orig that is not using recv_if.
 526  * Increases the returned neighbor's refcount
 527  */
 528 static struct batadv_neigh_node *
 529 batadv_find_ifalter_router(struct batadv_priv *bat_priv,
 530                            struct batadv_orig_node *primary_orig,
 531                            const struct batadv_hard_iface *recv_if)
 532 {
 533         struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
 534         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 535         struct batadv_neigh_node *tmp_neigh_node;
 536
 537         rcu_read_lock();
 538         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 539                                 bonding_list) {
 540                 if (!first_candidate)
 541                         first_candidate = tmp_neigh_node;
 542
 543                 /* recv_if == NULL on the first node. */
 544                 if (tmp_neigh_node->if_incoming == recv_if)
 545                         continue;
 546
 547                 if (router && bao->bat_neigh_cmp(tmp_neigh_node, router))
 548                         continue;
 549
 550                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 551                         continue;
 552
 553                 /* decrement refcount of previously selected router */
 554                 if (router)
 555                         batadv_neigh_node_free_ref(router);
 556
 557                 /* we found a better router (or at least one valid router) */
 558                 router = tmp_neigh_node;
 559         }
 560
 561         /* use the first candidate if nothing was found. */
 562         if (!router && first_candidate &&
 563             atomic_inc_not_zero(&first_candidate->refcount))
 564                 router = first_candidate;
 565
 566         rcu_read_unlock();
 567         return router;
 568 }
 569
 570 /**
 571  * batadv_check_unicast_packet - Check for malformed unicast packets
 572  * @bat_priv: the bat priv with all the soft interface information
 573  * @skb: packet to check
 574  * @hdr_size: size of header to pull
 575  *
 576  * Check for short header and bad addresses in given packet. Returns negative
 577  * value when check fails and 0 otherwise. The negative value depends on the
 578  * reason: -ENODATA for bad header, -EBADR for broadcast destination or source,
 579  * and -EREMOTE for non-local (other host) destination.
 580  */
 581 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 582                                        struct sk_buff *skb, int hdr_size)
 583 {
 584         struct ethhdr *ethhdr;
 585
 586         /* drop packet if it has not necessary minimum size */
 587         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 588                 return -ENODATA;
 589
 590         ethhdr = eth_hdr(skb);
 591
 592         /* packet with unicast indication but broadcast recipient */
 593         if (is_broadcast_ether_addr(ethhdr->h_dest))
 594                 return -EBADR;
 595
 596         /* packet with broadcast sender address */
 597         if (is_broadcast_ether_addr(ethhdr->h_source))
 598                 return -EBADR;
 599
 600         /* not for me */
 601         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 602                 return -EREMOTE;
 603
 604         return 0;
 605 }
 606
 607 /* find a suitable router for this originator, and use
 608  * bonding if possible. increases the found neighbors
 609  * refcount.
 610  */
 611 struct batadv_neigh_node *
 612 batadv_find_router(struct batadv_priv *bat_priv,
 613                    struct batadv_orig_node *orig_node,
 614                    const struct batadv_hard_iface *recv_if)
 615 {
 616         struct batadv_orig_node *primary_orig_node;
 617         struct batadv_orig_node *router_orig;
 618         struct batadv_neigh_node *router;
 619         static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
 620         int bonding_enabled;
 621         uint8_t *primary_addr;
 622
 623         if (!orig_node)
 624                 return NULL;
 625
 626         router = batadv_orig_node_get_router(orig_node);
 627         if (!router)
 628                 goto err;
 629
 630         /* without bonding, the first node should
 631          * always choose the default router.
 632          */
 633         bonding_enabled = atomic_read(&bat_priv->bonding);
 634
 635         rcu_read_lock();
 636         /* select default router to output */
 637         router_orig = router->orig_node;
 638         if (!router_orig)
 639                 goto err_unlock;
 640
 641         if ((!recv_if) && (!bonding_enabled))
 642                 goto return_router;
 643
 644         primary_addr = router_orig->primary_addr;
 645
 646         /* if we have something in the primary_addr, we can search
 647          * for a potential bonding candidate.
 648          */
 649         if (batadv_compare_eth(primary_addr, zero_mac))
 650                 goto return_router;
 651
 652         /* find the orig_node which has the primary interface. might
 653          * even be the same as our router_orig in many cases
 654          */
 655         if (batadv_compare_eth(primary_addr, router_orig->orig)) {
 656                 primary_orig_node = router_orig;
 657         } else {
 658                 primary_orig_node = batadv_orig_hash_find(bat_priv,
 659                                                           primary_addr);
 660                 if (!primary_orig_node)
 661                         goto return_router;
 662
 663                 batadv_orig_node_free_ref(primary_orig_node);
 664         }
 665
 666         /* with less than 2 candidates, we can't do any
 667          * bonding and prefer the original router.
 668          */
 669         if (atomic_read(&primary_orig_node->bond_candidates) < 2)
 670                 goto return_router;
 671
 672         /* all nodes between should choose a candidate which
 673          * is is not on the interface where the packet came
 674          * in.
 675          */
 676         batadv_neigh_node_free_ref(router);
 677
 678         if (bonding_enabled)
 679                 router = batadv_find_bond_router(primary_orig_node, recv_if);
 680         else
 681                 router = batadv_find_ifalter_router(bat_priv, primary_orig_node,
 682                                                     recv_if);
 683
 684 return_router:
 685         if (router && router->if_incoming->if_status != BATADV_IF_ACTIVE)
 686                 goto err_unlock;
 687
 688         rcu_read_unlock();
 689         return router;
 690 err_unlock:
 691         rcu_read_unlock();
 692 err:
 693         if (router)
 694                 batadv_neigh_node_free_ref(router);
 695         return NULL;
 696 }
 697
 698 static int batadv_route_unicast_packet(struct sk_buff *skb,
 699                                        struct batadv_hard_iface *recv_if)
 700 {
 701         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 702         struct batadv_orig_node *orig_node = NULL;
 703         struct batadv_unicast_packet *unicast_packet;
 704         struct ethhdr *ethhdr = eth_hdr(skb);
 705         int res, hdr_len, ret = NET_RX_DROP;
 706
 707         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 708
 709         /* TTL exceeded */
 710         if (unicast_packet->ttl < 2) {
 711                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 712                          ethhdr->h_source, unicast_packet->dest);
 713                 goto out;
 714         }
 715
 716         /* get routing information */
 717         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 718
 719         if (!orig_node)
 720                 goto out;
 721
 722         /* create a copy of the skb, if needed, to modify it. */
 723         if (skb_cow(skb, ETH_HLEN) < 0)
 724                 goto out;
 725
 726         /* decrement ttl */
 727         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 728         unicast_packet->ttl--;
 729
 730         switch (unicast_packet->packet_type) {
 731         case BATADV_UNICAST_4ADDR:
 732                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 733                 break;
 734         case BATADV_UNICAST:
 735                 hdr_len = sizeof(struct batadv_unicast_packet);
 736                 break;
 737         default:
 738                 /* other packet types not supported - yet */
 739                 hdr_len = -1;
 740                 break;
 741         }
 742
 743         if (hdr_len > 0)
 744                 batadv_skb_set_priority(skb, hdr_len);
 745
 746         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 747
 748         /* translate transmit result into receive result */
 749         if (res == NET_XMIT_SUCCESS) {
 750                 /* skb was transmitted and consumed */
 751                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 752                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 753                                    skb->len + ETH_HLEN);
 754
 755                 ret = NET_RX_SUCCESS;
 756         } else if (res == NET_XMIT_POLICED) {
 757                 /* skb was buffered and consumed */
 758                 ret = NET_RX_SUCCESS;
 759         }
 760
 761 out:
 762         if (orig_node)
 763                 batadv_orig_node_free_ref(orig_node);
 764         return ret;
 765 }
 766
 767 /**
 768  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 769  * @bat_priv: the bat priv with all the soft interface information
 770  * @unicast_packet: the unicast header to be updated
 771  * @dst_addr: the payload destination
 772  * @vid: VLAN identifier
 773  *
 774  * Search the translation table for dst_addr and update the unicast header with
 775  * the new corresponding information (originator address where the destination
 776  * client currently is and its known TTVN)
 777  *
 778  * Returns true if the packet header has been updated, false otherwise
 779  */
 780 static bool
 781 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 782                               struct batadv_unicast_packet *unicast_packet,
 783                               uint8_t *dst_addr, unsigned short vid)
 784 {
 785         struct batadv_orig_node *orig_node = NULL;
 786         struct batadv_hard_iface *primary_if = NULL;
 787         bool ret = false;
 788         uint8_t *orig_addr, orig_ttvn;
 789
 790         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 791                 primary_if = batadv_primary_if_get_selected(bat_priv);
 792                 if (!primary_if)
 793                         goto out;
 794                 orig_addr = primary_if->net_dev->dev_addr;
 795                 orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 796         } else {
 797                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 798                                                      vid);
 799                 if (!orig_node)
 800                         goto out;
 801
 802                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 803                         goto out;
 804
 805                 orig_addr = orig_node->orig;
 806                 orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 807         }
 808
 809         /* update the packet header */
 810         memcpy(unicast_packet->dest, orig_addr, ETH_ALEN);
 811         unicast_packet->ttvn = orig_ttvn;
 812
 813         ret = true;
 814 out:
 815         if (primary_if)
 816                 batadv_hardif_free_ref(primary_if);
 817         if (orig_node)
 818                 batadv_orig_node_free_ref(orig_node);
 819
 820         return ret;
 821 }
 822
 823 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 824                                      struct sk_buff *skb, int hdr_len) {
 825         struct batadv_unicast_packet *unicast_packet;
 826         struct batadv_hard_iface *primary_if;
 827         struct batadv_orig_node *orig_node;
 828         uint8_t curr_ttvn, old_ttvn;
 829         struct ethhdr *ethhdr;
 830         unsigned short vid;
 831         int is_old_ttvn;
 832
 833         /* check if there is enough data before accessing it */
 834         if (pskb_may_pull(skb, hdr_len + ETH_HLEN) < 0)
 835                 return 0;
 836
 837         /* create a copy of the skb (in case of for re-routing) to modify it. */
 838         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 839                 return 0;
 840
 841         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 842         vid = batadv_get_vid(skb, hdr_len);
 843         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 844
 845         /* check if the destination client was served by this node and it is now
 846          * roaming. In this case, it means that the node has got a ROAM_ADV
 847          * message and that it knows the new destination in the mesh to re-route
 848          * the packet to
 849          */
 850         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 851                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 852                                                   ethhdr->h_dest, vid))
 853                         net_ratelimited_function(batadv_dbg, BATADV_DBG_TT,
 854                                                  bat_priv,
 855                                                  "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 856                                                  unicast_packet->dest,
 857                                                  ethhdr->h_dest);
 858                 /* at this point the mesh destination should have been
 859                  * substituted with the originator address found in the global
 860                  * table. If not, let the packet go untouched anyway because
 861                  * there is nothing the node can do
 862                  */
 863                 return 1;
 864         }
 865
 866         /* retrieve the TTVN known by this node for the packet destination. This
 867          * value is used later to check if the node which sent (or re-routed
 868          * last time) the packet had an updated information or not
 869          */
 870         curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 871         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 872                 orig_node = batadv_orig_hash_find(bat_priv,
 873                                                   unicast_packet->dest);
 874                 /* if it is not possible to find the orig_node representing the
 875                  * destination, the packet can immediately be dropped as it will
 876                  * not be possible to deliver it
 877                  */
 878                 if (!orig_node)
 879                         return 0;
 880
 881                 curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 882                 batadv_orig_node_free_ref(orig_node);
 883         }
 884
 885         /* check if the TTVN contained in the packet is fresher than what the
 886          * node knows
 887          */
 888         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 889         if (!is_old_ttvn)
 890                 return 1;
 891
 892         old_ttvn = unicast_packet->ttvn;
 893         /* the packet was forged based on outdated network information. Its
 894          * destination can possibly be updated and forwarded towards the new
 895          * target host
 896          */
 897         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 898                                           ethhdr->h_dest, vid)) {
 899                 net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv,
 900                                          "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 901                                          unicast_packet->dest, ethhdr->h_dest,
 902                                          old_ttvn, curr_ttvn);
 903                 return 1;
 904         }
 905
 906         /* the packet has not been re-routed: either the destination is
 907          * currently served by this node or there is no destination at all and
 908          * it is possible to drop the packet
 909          */
 910         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 911                 return 0;
 912
 913         /* update the header in order to let the packet be delivered to this
 914          * node's soft interface
 915          */
 916         primary_if = batadv_primary_if_get_selected(bat_priv);
 917         if (!primary_if)
 918                 return 0;
 919
 920         memcpy(unicast_packet->dest, primary_if->net_dev->dev_addr, ETH_ALEN);
 921
 922         batadv_hardif_free_ref(primary_if);
 923
 924         unicast_packet->ttvn = curr_ttvn;
 925
 926         return 1;
 927 }
 928
 929 /**
 930  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 931  *      are in the unicast number space but not yet known to the implementation
 932  * @skb: unicast tvlv packet to process
 933  * @recv_if: pointer to interface this packet was received on
 934  *
 935  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 936  * otherwise.
 937  */
 938 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 939                                          struct batadv_hard_iface *recv_if)
 940 {
 941         struct batadv_unicast_packet *unicast_packet;
 942         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 943         int check, hdr_size = sizeof(*unicast_packet);
 944
 945         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 946         if (check < 0)
 947                 return NET_RX_DROP;
 948
 949         /* we don't know about this type, drop it. */
 950         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 951         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 952                 return NET_RX_DROP;
 953
 954         return batadv_route_unicast_packet(skb, recv_if);
 955 }
 956
 957 int batadv_recv_unicast_packet(struct sk_buff *skb,
 958                                struct batadv_hard_iface *recv_if)
 959 {
 960         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 961         struct batadv_unicast_packet *unicast_packet;
 962         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 963         uint8_t *orig_addr;
 964         struct batadv_orig_node *orig_node = NULL;
 965         int check, hdr_size = sizeof(*unicast_packet);
 966         bool is4addr;
 967
 968         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 969         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 970
 971         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 972         /* the caller function should have already pulled 2 bytes */
 973         if (is4addr)
 974                 hdr_size = sizeof(*unicast_4addr_packet);
 975
 976         /* function returns -EREMOTE for promiscuous packets */
 977         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 978
 979         /* Even though the packet is not for us, we might save it to use for
 980          * decoding a later received coded packet
 981          */
 982         if (check == -EREMOTE)
 983                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 984
 985         if (check < 0)
 986                 return NET_RX_DROP;
 987         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 988                 return NET_RX_DROP;
 989
 990         /* packet for me */
 991         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 992                 if (is4addr) {
 993                         batadv_dat_inc_counter(bat_priv,
 994                                                unicast_4addr_packet->subtype);
 995                         orig_addr = unicast_4addr_packet->src;
 996                         orig_node = batadv_orig_hash_find(bat_priv, orig_addr);
 997                 }
 998
 999                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
1000                                                           hdr_size))
1001                         goto rx_success;
1002                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
1003                                                         hdr_size))
1004                         goto rx_success;
1005
1006                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1007                                     orig_node);
1008
1009 rx_success:
1010                 if (orig_node)
1011                         batadv_orig_node_free_ref(orig_node);
1012
1013                 return NET_RX_SUCCESS;
1014         }
1015
1016         return batadv_route_unicast_packet(skb, recv_if);
1017 }
1018
1019 /**
1020  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
1021  * @skb: unicast tvlv packet to process
1022  * @recv_if: pointer to interface this packet was received on
1023  * @dst_addr: the payload destination
1024  *
1025  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1026  * otherwise.
1027  */
1028 int batadv_recv_unicast_tvlv(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_tvlv_packet *unicast_tvlv_packet;
1033         unsigned char *tvlv_buff;
1034         uint16_t tvlv_buff_len;
1035         int hdr_size = sizeof(*unicast_tvlv_packet);
1036         int ret = NET_RX_DROP;
1037
1038         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
1039                 return NET_RX_DROP;
1040
1041         /* the header is likely to be modified while forwarding */
1042         if (skb_cow(skb, hdr_size) < 0)
1043                 return NET_RX_DROP;
1044
1045         /* packet needs to be linearized to access the tvlv content */
1046         if (skb_linearize(skb) < 0)
1047                 return NET_RX_DROP;
1048
1049         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
1050
1051         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1052         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
1053
1054         if (tvlv_buff_len > skb->len - hdr_size)
1055                 return NET_RX_DROP;
1056
1057         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
1058                                              unicast_tvlv_packet->src,
1059                                              unicast_tvlv_packet->dst,
1060                                              tvlv_buff, tvlv_buff_len);
1061
1062         if (ret != NET_RX_SUCCESS)
1063                 ret = batadv_route_unicast_packet(skb, recv_if);
1064
1065         return ret;
1066 }
1067
1068 /**
1069  * batadv_recv_frag_packet - process received fragment
1070  * @skb: the received fragment
1071  * @recv_if: interface that the skb is received on
1072  *
1073  * This function does one of the three following things: 1) Forward fragment, if
1074  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
1075  * lack further fragments; 3) Merge fragments, if we have all needed parts.
1076  *
1077  * Return NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1078  */
1079 int batadv_recv_frag_packet(struct sk_buff *skb,
1080                             struct batadv_hard_iface *recv_if)
1081 {
1082         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1083         struct batadv_orig_node *orig_node_src = NULL;
1084         struct batadv_frag_packet *frag_packet;
1085         int ret = NET_RX_DROP;
1086
1087         if (batadv_check_unicast_packet(bat_priv, skb,
1088                                         sizeof(*frag_packet)) < 0)
1089                 goto out;
1090
1091         frag_packet = (struct batadv_frag_packet *)skb->data;
1092         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1093         if (!orig_node_src)
1094                 goto out;
1095
1096         /* Route the fragment if it is not for us and too big to be merged. */
1097         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1098             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1099                 ret = NET_RX_SUCCESS;
1100                 goto out;
1101         }
1102
1103         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1104         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1105
1106         /* Add fragment to buffer and merge if possible. */
1107         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1108                 goto out;
1109
1110         /* Deliver merged packet to the appropriate handler, if it was
1111          * merged
1112          */
1113         if (skb)
1114                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1115                                        &recv_if->batman_adv_ptype, NULL);
1116
1117         ret = NET_RX_SUCCESS;
1118
1119 out:
1120         if (orig_node_src)
1121                 batadv_orig_node_free_ref(orig_node_src);
1122
1123         return ret;
1124 }
1125
1126 int batadv_recv_bcast_packet(struct sk_buff *skb,
1127                              struct batadv_hard_iface *recv_if)
1128 {
1129         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1130         struct batadv_orig_node *orig_node = NULL;
1131         struct batadv_bcast_packet *bcast_packet;
1132         struct ethhdr *ethhdr;
1133         int hdr_size = sizeof(*bcast_packet);
1134         int ret = NET_RX_DROP;
1135         int32_t seq_diff;
1136         uint32_t seqno;
1137
1138         /* drop packet if it has not necessary minimum size */
1139         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1140                 goto out;
1141
1142         ethhdr = eth_hdr(skb);
1143
1144         /* packet with broadcast indication but unicast recipient */
1145         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1146                 goto out;
1147
1148         /* packet with broadcast sender address */
1149         if (is_broadcast_ether_addr(ethhdr->h_source))
1150                 goto out;
1151
1152         /* ignore broadcasts sent by myself */
1153         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1154                 goto out;
1155
1156         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1157
1158         /* ignore broadcasts originated by myself */
1159         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1160                 goto out;
1161
1162         if (bcast_packet->ttl < 2)
1163                 goto out;
1164
1165         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1166
1167         if (!orig_node)
1168                 goto out;
1169
1170         spin_lock_bh(&orig_node->bcast_seqno_lock);
1171
1172         seqno = ntohl(bcast_packet->seqno);
1173         /* check whether the packet is a duplicate */
1174         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1175                             seqno))
1176                 goto spin_unlock;
1177
1178         seq_diff = 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 = 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         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1198
1199         /* rebroadcast packet */
1200         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1201
1202         /* don't hand the broadcast up if it is from an originator
1203          * from the same backbone.
1204          */
1205         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1206                 goto out;
1207
1208         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1209                 goto rx_success;
1210         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1211                 goto rx_success;
1212
1213         /* broadcast for me */
1214         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1215                             orig_node);
1216
1217 rx_success:
1218         ret = NET_RX_SUCCESS;
1219         goto out;
1220
1221 spin_unlock:
1222         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1223 out:
1224         if (orig_node)
1225                 batadv_orig_node_free_ref(orig_node);
1226         return ret;
1227 }