net/batman-adv/routing.c

   1 /* Copyright (C) 2007-2013 B.A.T.M.A.N. contributors:
   2  *
   3  * Marek Lindner, Simon Wunderlich
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 2 of the GNU General Public
   7  * License as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA
  18  */
  19
  20 #include "main.h"
  21 #include "routing.h"
  22 #include "send.h"
  23 #include "soft-interface.h"
  24 #include "hard-interface.h"
  25 #include "icmp_socket.h"
  26 #include "translation-table.h"
  27 #include "originator.h"
  28 #include "unicast.h"
  29 #include "bridge_loop_avoidance.h"
  30 #include "distributed-arp-table.h"
  31 #include "network-coding.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,
  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 void batadv_bonding_candidate_add(struct batadv_orig_node *orig_node,
 117                                   struct batadv_neigh_node *neigh_node)
 118 {
 119         struct batadv_neigh_node *tmp_neigh_node, *router = NULL;
 120         uint8_t interference_candidate = 0;
 121
 122         spin_lock_bh(&orig_node->neigh_list_lock);
 123
 124         /* only consider if it has the same primary address ...  */
 125         if (!batadv_compare_eth(orig_node->orig,
 126                                 neigh_node->orig_node->primary_addr))
 127                 goto candidate_del;
 128
 129         router = batadv_orig_node_get_router(orig_node);
 130         if (!router)
 131                 goto candidate_del;
 132
 133         /* ... and is good enough to be considered */
 134         if (neigh_node->tq_avg < router->tq_avg - BATADV_BONDING_TQ_THRESHOLD)
 135                 goto candidate_del;
 136
 137         /* check if we have another candidate with the same mac address or
 138          * interface. If we do, we won't select this candidate because of
 139          * possible interference.
 140          */
 141         hlist_for_each_entry_rcu(tmp_neigh_node,
 142                                  &orig_node->neigh_list, list) {
 143                 if (tmp_neigh_node == neigh_node)
 144                         continue;
 145
 146                 /* we only care if the other candidate is even
 147                  * considered as candidate.
 148                  */
 149                 if (list_empty(&tmp_neigh_node->bonding_list))
 150                         continue;
 151
 152                 if ((neigh_node->if_incoming == tmp_neigh_node->if_incoming) ||
 153                     (batadv_compare_eth(neigh_node->addr,
 154                                         tmp_neigh_node->addr))) {
 155                         interference_candidate = 1;
 156                         break;
 157                 }
 158         }
 159
 160         /* don't care further if it is an interference candidate */
 161         if (interference_candidate)
 162                 goto candidate_del;
 163
 164         /* this neighbor already is part of our candidate list */
 165         if (!list_empty(&neigh_node->bonding_list))
 166                 goto out;
 167
 168         if (!atomic_inc_not_zero(&neigh_node->refcount))
 169                 goto out;
 170
 171         list_add_rcu(&neigh_node->bonding_list, &orig_node->bond_list);
 172         atomic_inc(&orig_node->bond_candidates);
 173         goto out;
 174
 175 candidate_del:
 176         batadv_bonding_candidate_del(orig_node, neigh_node);
 177
 178 out:
 179         spin_unlock_bh(&orig_node->neigh_list_lock);
 180
 181         if (router)
 182                 batadv_neigh_node_free_ref(router);
 183 }
 184
 185 /* copy primary address for bonding */
 186 void
 187 batadv_bonding_save_primary(const struct batadv_orig_node *orig_node,
 188                             struct batadv_orig_node *orig_neigh_node,
 189                             const struct batadv_ogm_packet *batman_ogm_packet)
 190 {
 191         if (!(batman_ogm_packet->flags & BATADV_PRIMARIES_FIRST_HOP))
 192                 return;
 193
 194         memcpy(orig_neigh_node->primary_addr, orig_node->orig, ETH_ALEN);
 195 }
 196
 197 /* checks whether the host restarted and is in the protection time.
 198  * returns:
 199  *  0 if the packet is to be accepted
 200  *  1 if the packet is to be ignored.
 201  */
 202 int batadv_window_protected(struct batadv_priv *bat_priv, int32_t seq_num_diff,
 203                             unsigned long *last_reset)
 204 {
 205         if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
 206             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 207                 if (!batadv_has_timed_out(*last_reset,
 208                                           BATADV_RESET_PROTECTION_MS))
 209                         return 1;
 210
 211                 *last_reset = jiffies;
 212                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 213                            "old packet received, start protection\n");
 214         }
 215
 216         return 0;
 217 }
 218
 219 bool batadv_check_management_packet(struct sk_buff *skb,
 220                                     struct batadv_hard_iface *hard_iface,
 221                                     int header_len)
 222 {
 223         struct ethhdr *ethhdr;
 224
 225         /* drop packet if it has not necessary minimum size */
 226         if (unlikely(!pskb_may_pull(skb, header_len)))
 227                 return false;
 228
 229         ethhdr = eth_hdr(skb);
 230
 231         /* packet with broadcast indication but unicast recipient */
 232         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 233                 return false;
 234
 235         /* packet with broadcast sender address */
 236         if (is_broadcast_ether_addr(ethhdr->h_source))
 237                 return false;
 238
 239         /* create a copy of the skb, if needed, to modify it. */
 240         if (skb_cow(skb, 0) < 0)
 241                 return false;
 242
 243         /* keep skb linear */
 244         if (skb_linearize(skb) < 0)
 245                 return false;
 246
 247         return true;
 248 }
 249
 250 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 251                                       struct sk_buff *skb, size_t icmp_len)
 252 {
 253         struct batadv_hard_iface *primary_if = NULL;
 254         struct batadv_orig_node *orig_node = NULL;
 255         struct batadv_icmp_packet_rr *icmp_packet;
 256         int ret = NET_RX_DROP;
 257
 258         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 259
 260         /* add data to device queue */
 261         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 262                 batadv_socket_receive_packet(icmp_packet, icmp_len);
 263                 goto out;
 264         }
 265
 266         primary_if = batadv_primary_if_get_selected(bat_priv);
 267         if (!primary_if)
 268                 goto out;
 269
 270         /* answer echo request (ping) */
 271         /* get routing information */
 272         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 273         if (!orig_node)
 274                 goto out;
 275
 276         /* create a copy of the skb, if needed, to modify it. */
 277         if (skb_cow(skb, ETH_HLEN) < 0)
 278                 goto out;
 279
 280         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 281
 282         memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
 283         memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 284         icmp_packet->msg_type = BATADV_ECHO_REPLY;
 285         icmp_packet->header.ttl = BATADV_TTL;
 286
 287         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 288                 ret = NET_RX_SUCCESS;
 289
 290 out:
 291         if (primary_if)
 292                 batadv_hardif_free_ref(primary_if);
 293         if (orig_node)
 294                 batadv_orig_node_free_ref(orig_node);
 295         return ret;
 296 }
 297
 298 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 299                                          struct sk_buff *skb)
 300 {
 301         struct batadv_hard_iface *primary_if = NULL;
 302         struct batadv_orig_node *orig_node = NULL;
 303         struct batadv_icmp_packet *icmp_packet;
 304         int ret = NET_RX_DROP;
 305
 306         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 307
 308         /* send TTL exceeded if packet is an echo request (traceroute) */
 309         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 310                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 311                          icmp_packet->orig, icmp_packet->dst);
 312                 goto out;
 313         }
 314
 315         primary_if = batadv_primary_if_get_selected(bat_priv);
 316         if (!primary_if)
 317                 goto out;
 318
 319         /* get routing information */
 320         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 321         if (!orig_node)
 322                 goto out;
 323
 324         /* create a copy of the skb, if needed, to modify it. */
 325         if (skb_cow(skb, ETH_HLEN) < 0)
 326                 goto out;
 327
 328         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 329
 330         memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
 331         memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 332         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 333         icmp_packet->header.ttl = BATADV_TTL;
 334
 335         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 336                 ret = NET_RX_SUCCESS;
 337
 338 out:
 339         if (primary_if)
 340                 batadv_hardif_free_ref(primary_if);
 341         if (orig_node)
 342                 batadv_orig_node_free_ref(orig_node);
 343         return ret;
 344 }
 345
 346
 347 int batadv_recv_icmp_packet(struct sk_buff *skb,
 348                             struct batadv_hard_iface *recv_if)
 349 {
 350         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 351         struct batadv_icmp_packet_rr *icmp_packet;
 352         struct ethhdr *ethhdr;
 353         struct batadv_orig_node *orig_node = NULL;
 354         int hdr_size = sizeof(struct batadv_icmp_packet);
 355         int ret = NET_RX_DROP;
 356
 357         /* we truncate all incoming icmp packets if they don't match our size */
 358         if (skb->len >= sizeof(struct batadv_icmp_packet_rr))
 359                 hdr_size = sizeof(struct batadv_icmp_packet_rr);
 360
 361         /* drop packet if it has not necessary minimum size */
 362         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 363                 goto out;
 364
 365         ethhdr = eth_hdr(skb);
 366
 367         /* packet with unicast indication but broadcast recipient */
 368         if (is_broadcast_ether_addr(ethhdr->h_dest))
 369                 goto out;
 370
 371         /* packet with broadcast sender address */
 372         if (is_broadcast_ether_addr(ethhdr->h_source))
 373                 goto out;
 374
 375         /* not for me */
 376         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 377                 goto out;
 378
 379         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 380
 381         /* add record route information if not full */
 382         if ((icmp_packet->msg_type == BATADV_ECHO_REPLY ||
 383              icmp_packet->msg_type == BATADV_ECHO_REQUEST) &&
 384             (hdr_size == sizeof(struct batadv_icmp_packet_rr)) &&
 385             (icmp_packet->rr_cur < BATADV_RR_LEN)) {
 386                 memcpy(&(icmp_packet->rr[icmp_packet->rr_cur]),
 387                        ethhdr->h_dest, ETH_ALEN);
 388                 icmp_packet->rr_cur++;
 389         }
 390
 391         /* packet for me */
 392         if (batadv_is_my_mac(bat_priv, icmp_packet->dst))
 393                 return batadv_recv_my_icmp_packet(bat_priv, skb, hdr_size);
 394
 395         /* TTL exceeded */
 396         if (icmp_packet->header.ttl < 2)
 397                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 398
 399         /* get routing information */
 400         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->dst);
 401         if (!orig_node)
 402                 goto out;
 403
 404         /* create a copy of the skb, if needed, to modify it. */
 405         if (skb_cow(skb, ETH_HLEN) < 0)
 406                 goto out;
 407
 408         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 409
 410         /* decrement ttl */
 411         icmp_packet->header.ttl--;
 412
 413         /* route it */
 414         if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
 415                 ret = NET_RX_SUCCESS;
 416
 417 out:
 418         if (orig_node)
 419                 batadv_orig_node_free_ref(orig_node);
 420         return ret;
 421 }
 422
 423 /* In the bonding case, send the packets in a round
 424  * robin fashion over the remaining interfaces.
 425  *
 426  * This method rotates the bonding list and increases the
 427  * returned router's refcount.
 428  */
 429 static struct batadv_neigh_node *
 430 batadv_find_bond_router(struct batadv_orig_node *primary_orig,
 431                         const struct batadv_hard_iface *recv_if)
 432 {
 433         struct batadv_neigh_node *tmp_neigh_node;
 434         struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
 435
 436         rcu_read_lock();
 437         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 438                                 bonding_list) {
 439                 if (!first_candidate)
 440                         first_candidate = tmp_neigh_node;
 441
 442                 /* recv_if == NULL on the first node. */
 443                 if (tmp_neigh_node->if_incoming == recv_if)
 444                         continue;
 445
 446                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 447                         continue;
 448
 449                 router = tmp_neigh_node;
 450                 break;
 451         }
 452
 453         /* use the first candidate if nothing was found. */
 454         if (!router && first_candidate &&
 455             atomic_inc_not_zero(&first_candidate->refcount))
 456                 router = first_candidate;
 457
 458         if (!router)
 459                 goto out;
 460
 461         /* selected should point to the next element
 462          * after the current router
 463          */
 464         spin_lock_bh(&primary_orig->neigh_list_lock);
 465         /* this is a list_move(), which unfortunately
 466          * does not exist as rcu version
 467          */
 468         list_del_rcu(&primary_orig->bond_list);
 469         list_add_rcu(&primary_orig->bond_list,
 470                      &router->bonding_list);
 471         spin_unlock_bh(&primary_orig->neigh_list_lock);
 472
 473 out:
 474         rcu_read_unlock();
 475         return router;
 476 }
 477
 478 /* Interface Alternating: Use the best of the
 479  * remaining candidates which are not using
 480  * this interface.
 481  *
 482  * Increases the returned router's refcount
 483  */
 484 static struct batadv_neigh_node *
 485 batadv_find_ifalter_router(struct batadv_orig_node *primary_orig,
 486                            const struct batadv_hard_iface *recv_if)
 487 {
 488         struct batadv_neigh_node *tmp_neigh_node;
 489         struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
 490
 491         rcu_read_lock();
 492         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 493                                 bonding_list) {
 494                 if (!first_candidate)
 495                         first_candidate = tmp_neigh_node;
 496
 497                 /* recv_if == NULL on the first node. */
 498                 if (tmp_neigh_node->if_incoming == recv_if)
 499                         continue;
 500
 501                 if (router && tmp_neigh_node->tq_avg <= router->tq_avg)
 502                         continue;
 503
 504                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 505                         continue;
 506
 507                 /* decrement refcount of previously selected router */
 508                 if (router)
 509                         batadv_neigh_node_free_ref(router);
 510
 511                 /* we found a better router (or at least one valid router) */
 512                 router = tmp_neigh_node;
 513         }
 514
 515         /* use the first candidate if nothing was found. */
 516         if (!router && first_candidate &&
 517             atomic_inc_not_zero(&first_candidate->refcount))
 518                 router = first_candidate;
 519
 520         rcu_read_unlock();
 521         return router;
 522 }
 523
 524 /**
 525  * batadv_check_unicast_packet - Check for malformed unicast packets
 526  * @bat_priv: the bat priv with all the soft interface information
 527  * @skb: packet to check
 528  * @hdr_size: size of header to pull
 529  *
 530  * Check for short header and bad addresses in given packet. Returns negative
 531  * value when check fails and 0 otherwise. The negative value depends on the
 532  * reason: -ENODATA for bad header, -EBADR for broadcast destination or source,
 533  * and -EREMOTE for non-local (other host) destination.
 534  */
 535 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 536                                        struct sk_buff *skb, int hdr_size)
 537 {
 538         struct ethhdr *ethhdr;
 539
 540         /* drop packet if it has not necessary minimum size */
 541         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 542                 return -ENODATA;
 543
 544         ethhdr = eth_hdr(skb);
 545
 546         /* packet with unicast indication but broadcast recipient */
 547         if (is_broadcast_ether_addr(ethhdr->h_dest))
 548                 return -EBADR;
 549
 550         /* packet with broadcast sender address */
 551         if (is_broadcast_ether_addr(ethhdr->h_source))
 552                 return -EBADR;
 553
 554         /* not for me */
 555         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 556                 return -EREMOTE;
 557
 558         return 0;
 559 }
 560
 561 /* find a suitable router for this originator, and use
 562  * bonding if possible. increases the found neighbors
 563  * refcount.
 564  */
 565 struct batadv_neigh_node *
 566 batadv_find_router(struct batadv_priv *bat_priv,
 567                    struct batadv_orig_node *orig_node,
 568                    const struct batadv_hard_iface *recv_if)
 569 {
 570         struct batadv_orig_node *primary_orig_node;
 571         struct batadv_orig_node *router_orig;
 572         struct batadv_neigh_node *router;
 573         static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
 574         int bonding_enabled;
 575         uint8_t *primary_addr;
 576
 577         if (!orig_node)
 578                 return NULL;
 579
 580         router = batadv_orig_node_get_router(orig_node);
 581         if (!router)
 582                 goto err;
 583
 584         /* without bonding, the first node should
 585          * always choose the default router.
 586          */
 587         bonding_enabled = atomic_read(&bat_priv->bonding);
 588
 589         rcu_read_lock();
 590         /* select default router to output */
 591         router_orig = router->orig_node;
 592         if (!router_orig)
 593                 goto err_unlock;
 594
 595         if ((!recv_if) && (!bonding_enabled))
 596                 goto return_router;
 597
 598         primary_addr = router_orig->primary_addr;
 599
 600         /* if we have something in the primary_addr, we can search
 601          * for a potential bonding candidate.
 602          */
 603         if (batadv_compare_eth(primary_addr, zero_mac))
 604                 goto return_router;
 605
 606         /* find the orig_node which has the primary interface. might
 607          * even be the same as our router_orig in many cases
 608          */
 609         if (batadv_compare_eth(primary_addr, router_orig->orig)) {
 610                 primary_orig_node = router_orig;
 611         } else {
 612                 primary_orig_node = batadv_orig_hash_find(bat_priv,
 613                                                           primary_addr);
 614                 if (!primary_orig_node)
 615                         goto return_router;
 616
 617                 batadv_orig_node_free_ref(primary_orig_node);
 618         }
 619
 620         /* with less than 2 candidates, we can't do any
 621          * bonding and prefer the original router.
 622          */
 623         if (atomic_read(&primary_orig_node->bond_candidates) < 2)
 624                 goto return_router;
 625
 626         /* all nodes between should choose a candidate which
 627          * is is not on the interface where the packet came
 628          * in.
 629          */
 630         batadv_neigh_node_free_ref(router);
 631
 632         if (bonding_enabled)
 633                 router = batadv_find_bond_router(primary_orig_node, recv_if);
 634         else
 635                 router = batadv_find_ifalter_router(primary_orig_node, recv_if);
 636
 637 return_router:
 638         if (router && router->if_incoming->if_status != BATADV_IF_ACTIVE)
 639                 goto err_unlock;
 640
 641         rcu_read_unlock();
 642         return router;
 643 err_unlock:
 644         rcu_read_unlock();
 645 err:
 646         if (router)
 647                 batadv_neigh_node_free_ref(router);
 648         return NULL;
 649 }
 650
 651 static int batadv_route_unicast_packet(struct sk_buff *skb,
 652                                        struct batadv_hard_iface *recv_if)
 653 {
 654         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 655         struct batadv_orig_node *orig_node = NULL;
 656         struct batadv_neigh_node *neigh_node = NULL;
 657         struct batadv_unicast_packet *unicast_packet;
 658         struct ethhdr *ethhdr = eth_hdr(skb);
 659         int res, hdr_len, ret = NET_RX_DROP;
 660         struct sk_buff *new_skb;
 661
 662         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 663
 664         /* TTL exceeded */
 665         if (unicast_packet->header.ttl < 2) {
 666                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 667                          ethhdr->h_source, unicast_packet->dest);
 668                 goto out;
 669         }
 670
 671         /* get routing information */
 672         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 673
 674         if (!orig_node)
 675                 goto out;
 676
 677         /* find_router() increases neigh_nodes refcount if found. */
 678         neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
 679
 680         if (!neigh_node)
 681                 goto out;
 682
 683         /* create a copy of the skb, if needed, to modify it. */
 684         if (skb_cow(skb, ETH_HLEN) < 0)
 685                 goto out;
 686
 687         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 688
 689         if (unicast_packet->header.packet_type == BATADV_UNICAST &&
 690             atomic_read(&bat_priv->fragmentation) &&
 691             skb->len > neigh_node->if_incoming->net_dev->mtu) {
 692                 ret = batadv_frag_send_skb(skb, bat_priv,
 693                                            neigh_node->if_incoming,
 694                                            neigh_node->addr);
 695                 goto out;
 696         }
 697
 698         if (unicast_packet->header.packet_type == BATADV_UNICAST_FRAG &&
 699             batadv_frag_can_reassemble(skb,
 700                                        neigh_node->if_incoming->net_dev->mtu)) {
 701                 ret = batadv_frag_reassemble_skb(skb, bat_priv, &new_skb);
 702
 703                 if (ret == NET_RX_DROP)
 704                         goto out;
 705
 706                 /* packet was buffered for late merge */
 707                 if (!new_skb) {
 708                         ret = NET_RX_SUCCESS;
 709                         goto out;
 710                 }
 711
 712                 skb = new_skb;
 713                 unicast_packet = (struct batadv_unicast_packet *)skb->data;
 714         }
 715
 716         /* decrement ttl */
 717         unicast_packet->header.ttl--;
 718
 719         switch (unicast_packet->header.packet_type) {
 720         case BATADV_UNICAST_4ADDR:
 721                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 722                 break;
 723         case BATADV_UNICAST:
 724                 hdr_len = sizeof(struct batadv_unicast_packet);
 725                 break;
 726         default:
 727                 /* other packet types not supported - yet */
 728                 hdr_len = -1;
 729                 break;
 730         }
 731
 732         if (hdr_len > 0)
 733                 batadv_skb_set_priority(skb, hdr_len);
 734
 735         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 736
 737         /* translate transmit result into receive result */
 738         if (res == NET_XMIT_SUCCESS) {
 739                 /* skb was transmitted and consumed */
 740                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 741                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 742                                    skb->len + ETH_HLEN);
 743
 744                 ret = NET_RX_SUCCESS;
 745         } else if (res == NET_XMIT_POLICED) {
 746                 /* skb was buffered and consumed */
 747                 ret = NET_RX_SUCCESS;
 748         }
 749
 750 out:
 751         if (neigh_node)
 752                 batadv_neigh_node_free_ref(neigh_node);
 753         if (orig_node)
 754                 batadv_orig_node_free_ref(orig_node);
 755         return ret;
 756 }
 757
 758 /**
 759  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 760  * @bat_priv: the bat priv with all the soft interface information
 761  * @unicast_packet: the unicast header to be updated
 762  * @dst_addr: the payload destination
 763  *
 764  * Search the translation table for dst_addr and update the unicast header with
 765  * the new corresponding information (originator address where the destination
 766  * client currently is and its known TTVN)
 767  *
 768  * Returns true if the packet header has been updated, false otherwise
 769  */
 770 static bool
 771 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 772                               struct batadv_unicast_packet *unicast_packet,
 773                               uint8_t *dst_addr)
 774 {
 775         struct batadv_orig_node *orig_node = NULL;
 776         struct batadv_hard_iface *primary_if = NULL;
 777         bool ret = false;
 778         uint8_t *orig_addr, orig_ttvn;
 779
 780         if (batadv_is_my_client(bat_priv, dst_addr)) {
 781                 primary_if = batadv_primary_if_get_selected(bat_priv);
 782                 if (!primary_if)
 783                         goto out;
 784                 orig_addr = primary_if->net_dev->dev_addr;
 785                 orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 786         } else {
 787                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr);
 788                 if (!orig_node)
 789                         goto out;
 790
 791                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 792                         goto out;
 793
 794                 orig_addr = orig_node->orig;
 795                 orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 796         }
 797
 798         /* update the packet header */
 799         memcpy(unicast_packet->dest, orig_addr, ETH_ALEN);
 800         unicast_packet->ttvn = orig_ttvn;
 801
 802         ret = true;
 803 out:
 804         if (primary_if)
 805                 batadv_hardif_free_ref(primary_if);
 806         if (orig_node)
 807                 batadv_orig_node_free_ref(orig_node);
 808
 809         return ret;
 810 }
 811
 812 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 813                                      struct sk_buff *skb, int hdr_len) {
 814         uint8_t curr_ttvn, old_ttvn;
 815         struct batadv_orig_node *orig_node;
 816         struct ethhdr *ethhdr;
 817         struct batadv_hard_iface *primary_if;
 818         struct batadv_unicast_packet *unicast_packet;
 819         int is_old_ttvn;
 820
 821         /* check if there is enough data before accessing it */
 822         if (pskb_may_pull(skb, hdr_len + ETH_HLEN) < 0)
 823                 return 0;
 824
 825         /* create a copy of the skb (in case of for re-routing) to modify it. */
 826         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 827                 return 0;
 828
 829         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 830         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 831
 832         /* check if the destination client was served by this node and it is now
 833          * roaming. In this case, it means that the node has got a ROAM_ADV
 834          * message and that it knows the new destination in the mesh to re-route
 835          * the packet to
 836          */
 837         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest)) {
 838                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 839                                                   ethhdr->h_dest))
 840                         net_ratelimited_function(batadv_dbg, BATADV_DBG_TT,
 841                                                  bat_priv,
 842                                                  "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 843                                                  unicast_packet->dest,
 844                                                  ethhdr->h_dest);
 845                 /* at this point the mesh destination should have been
 846                  * substituted with the originator address found in the global
 847                  * table. If not, let the packet go untouched anyway because
 848                  * there is nothing the node can do
 849                  */
 850                 return 1;
 851         }
 852
 853         /* retrieve the TTVN known by this node for the packet destination. This
 854          * value is used later to check if the node which sent (or re-routed
 855          * last time) the packet had an updated information or not
 856          */
 857         curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 858         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 859                 orig_node = batadv_orig_hash_find(bat_priv,
 860                                                   unicast_packet->dest);
 861                 /* if it is not possible to find the orig_node representing the
 862                  * destination, the packet can immediately be dropped as it will
 863                  * not be possible to deliver it
 864                  */
 865                 if (!orig_node)
 866                         return 0;
 867
 868                 curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 869                 batadv_orig_node_free_ref(orig_node);
 870         }
 871
 872         /* check if the TTVN contained in the packet is fresher than what the
 873          * node knows
 874          */
 875         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 876         if (!is_old_ttvn)
 877                 return 1;
 878
 879         old_ttvn = unicast_packet->ttvn;
 880         /* the packet was forged based on outdated network information. Its
 881          * destination can possibly be updated and forwarded towards the new
 882          * target host
 883          */
 884         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 885                                           ethhdr->h_dest)) {
 886                 net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv,
 887                                          "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 888                                          unicast_packet->dest, ethhdr->h_dest,
 889                                          old_ttvn, curr_ttvn);
 890                 return 1;
 891         }
 892
 893         /* the packet has not been re-routed: either the destination is
 894          * currently served by this node or there is no destination at all and
 895          * it is possible to drop the packet
 896          */
 897         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest))
 898                 return 0;
 899
 900         /* update the header in order to let the packet be delivered to this
 901          * node's soft interface
 902          */
 903         primary_if = batadv_primary_if_get_selected(bat_priv);
 904         if (!primary_if)
 905                 return 0;
 906
 907         memcpy(unicast_packet->dest, primary_if->net_dev->dev_addr, ETH_ALEN);
 908
 909         batadv_hardif_free_ref(primary_if);
 910
 911         unicast_packet->ttvn = curr_ttvn;
 912
 913         return 1;
 914 }
 915
 916 /**
 917  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 918  *      are in the unicast number space but not yet known to the implementation
 919  * @skb: unicast tvlv packet to process
 920  * @recv_if: pointer to interface this packet was received on
 921  *
 922  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 923  * otherwise.
 924  */
 925 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 926                                          struct batadv_hard_iface *recv_if)
 927 {
 928         struct batadv_unicast_packet *unicast_packet;
 929         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 930         int check, hdr_size = sizeof(*unicast_packet);
 931
 932         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 933         if (check < 0)
 934                 return NET_RX_DROP;
 935
 936         /* we don't know about this type, drop it. */
 937         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 938         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 939                 return NET_RX_DROP;
 940
 941         return batadv_route_unicast_packet(skb, recv_if);
 942 }
 943
 944 int batadv_recv_unicast_packet(struct sk_buff *skb,
 945                                struct batadv_hard_iface *recv_if)
 946 {
 947         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 948         struct batadv_unicast_packet *unicast_packet;
 949         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 950         uint8_t *orig_addr;
 951         struct batadv_orig_node *orig_node = NULL;
 952         int check, hdr_size = sizeof(*unicast_packet);
 953         bool is4addr;
 954
 955         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 956         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 957
 958         is4addr = unicast_packet->header.packet_type == BATADV_UNICAST_4ADDR;
 959         /* the caller function should have already pulled 2 bytes */
 960         if (is4addr)
 961                 hdr_size = sizeof(*unicast_4addr_packet);
 962
 963         /* function returns -EREMOTE for promiscuous packets */
 964         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 965
 966         /* Even though the packet is not for us, we might save it to use for
 967          * decoding a later received coded packet
 968          */
 969         if (check == -EREMOTE)
 970                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 971
 972         if (check < 0)
 973                 return NET_RX_DROP;
 974         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 975                 return NET_RX_DROP;
 976
 977         /* packet for me */
 978         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 979                 if (is4addr) {
 980                         batadv_dat_inc_counter(bat_priv,
 981                                                unicast_4addr_packet->subtype);
 982                         orig_addr = unicast_4addr_packet->src;
 983                         orig_node = batadv_orig_hash_find(bat_priv, orig_addr);
 984                 }
 985
 986                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 987                                                           hdr_size))
 988                         goto rx_success;
 989                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 990                                                         hdr_size))
 991                         goto rx_success;
 992
 993                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
 994                                     orig_node);
 995
 996 rx_success:
 997                 if (orig_node)
 998                         batadv_orig_node_free_ref(orig_node);
 999
1000                 return NET_RX_SUCCESS;
1001         }
1002
1003         return batadv_route_unicast_packet(skb, recv_if);
1004 }
1005
1006 int batadv_recv_ucast_frag_packet(struct sk_buff *skb,
1007                                   struct batadv_hard_iface *recv_if)
1008 {
1009         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1010         struct batadv_unicast_frag_packet *unicast_packet;
1011         int hdr_size = sizeof(*unicast_packet);
1012         struct sk_buff *new_skb = NULL;
1013         int ret;
1014
1015         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
1016                 return NET_RX_DROP;
1017
1018         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
1019                 return NET_RX_DROP;
1020
1021         unicast_packet = (struct batadv_unicast_frag_packet *)skb->data;
1022
1023         /* packet for me */
1024         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
1025                 ret = batadv_frag_reassemble_skb(skb, bat_priv, &new_skb);
1026
1027                 if (ret == NET_RX_DROP)
1028                         return NET_RX_DROP;
1029
1030                 /* packet was buffered for late merge */
1031                 if (!new_skb)
1032                         return NET_RX_SUCCESS;
1033
1034                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, new_skb,
1035                                                           hdr_size))
1036                         goto rx_success;
1037                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, new_skb,
1038                                                         hdr_size))
1039                         goto rx_success;
1040
1041                 batadv_interface_rx(recv_if->soft_iface, new_skb, recv_if,
1042                                     sizeof(struct batadv_unicast_packet), NULL);
1043
1044 rx_success:
1045                 return NET_RX_SUCCESS;
1046         }
1047
1048         return batadv_route_unicast_packet(skb, recv_if);
1049 }
1050
1051 /**
1052  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
1053  * @skb: unicast tvlv packet to process
1054  * @recv_if: pointer to interface this packet was received on
1055  * @dst_addr: the payload destination
1056  *
1057  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1058  * otherwise.
1059  */
1060 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
1061                              struct batadv_hard_iface *recv_if)
1062 {
1063         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1064         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
1065         unsigned char *tvlv_buff;
1066         uint16_t tvlv_buff_len;
1067         int hdr_size = sizeof(*unicast_tvlv_packet);
1068         int ret = NET_RX_DROP;
1069
1070         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
1071                 return NET_RX_DROP;
1072
1073         /* the header is likely to be modified while forwarding */
1074         if (skb_cow(skb, hdr_size) < 0)
1075                 return NET_RX_DROP;
1076
1077         /* packet needs to be linearized to access the tvlv content */
1078         if (skb_linearize(skb) < 0)
1079                 return NET_RX_DROP;
1080
1081         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
1082
1083         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1084         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
1085
1086         if (tvlv_buff_len > skb->len - hdr_size)
1087                 return NET_RX_DROP;
1088
1089         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
1090                                              unicast_tvlv_packet->src,
1091                                              unicast_tvlv_packet->dst,
1092                                              tvlv_buff, tvlv_buff_len);
1093
1094         if (ret != NET_RX_SUCCESS)
1095                 ret = batadv_route_unicast_packet(skb, recv_if);
1096
1097         return ret;
1098 }
1099
1100 int batadv_recv_bcast_packet(struct sk_buff *skb,
1101                              struct batadv_hard_iface *recv_if)
1102 {
1103         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1104         struct batadv_orig_node *orig_node = NULL;
1105         struct batadv_bcast_packet *bcast_packet;
1106         struct ethhdr *ethhdr;
1107         int hdr_size = sizeof(*bcast_packet);
1108         int ret = NET_RX_DROP;
1109         int32_t seq_diff;
1110
1111         /* drop packet if it has not necessary minimum size */
1112         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1113                 goto out;
1114
1115         ethhdr = eth_hdr(skb);
1116
1117         /* packet with broadcast indication but unicast recipient */
1118         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1119                 goto out;
1120
1121         /* packet with broadcast sender address */
1122         if (is_broadcast_ether_addr(ethhdr->h_source))
1123                 goto out;
1124
1125         /* ignore broadcasts sent by myself */
1126         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1127                 goto out;
1128
1129         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1130
1131         /* ignore broadcasts originated by myself */
1132         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1133                 goto out;
1134
1135         if (bcast_packet->header.ttl < 2)
1136                 goto out;
1137
1138         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1139
1140         if (!orig_node)
1141                 goto out;
1142
1143         spin_lock_bh(&orig_node->bcast_seqno_lock);
1144
1145         /* check whether the packet is a duplicate */
1146         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1147                             ntohl(bcast_packet->seqno)))
1148                 goto spin_unlock;
1149
1150         seq_diff = ntohl(bcast_packet->seqno) - orig_node->last_bcast_seqno;
1151
1152         /* check whether the packet is old and the host just restarted. */
1153         if (batadv_window_protected(bat_priv, seq_diff,
1154                                     &orig_node->bcast_seqno_reset))
1155                 goto spin_unlock;
1156
1157         /* mark broadcast in flood history, update window position
1158          * if required.
1159          */
1160         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1161                 orig_node->last_bcast_seqno = ntohl(bcast_packet->seqno);
1162
1163         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1164
1165         /* check whether this has been sent by another originator before */
1166         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1167                 goto out;
1168
1169         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1170
1171         /* rebroadcast packet */
1172         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1173
1174         /* don't hand the broadcast up if it is from an originator
1175          * from the same backbone.
1176          */
1177         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1178                 goto out;
1179
1180         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1181                 goto rx_success;
1182         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1183                 goto rx_success;
1184
1185         /* broadcast for me */
1186         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1187                             orig_node);
1188
1189 rx_success:
1190         ret = NET_RX_SUCCESS;
1191         goto out;
1192
1193 spin_unlock:
1194         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1195 out:
1196         if (orig_node)
1197                 batadv_orig_node_free_ref(orig_node);
1198         return ret;
1199 }