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 "bridge_loop_avoidance.h"
  29 #include "distributed-arp-table.h"
  30 #include "network-coding.h"
  31 #include "fragmentation.h"
  32
  33 #include <linux/if_vlan.h>
  34
  35 static int batadv_route_unicast_packet(struct sk_buff *skb,
  36                                        struct batadv_hard_iface *recv_if);
  37
  38 static void _batadv_update_route(struct batadv_priv *bat_priv,
  39                                  struct batadv_orig_node *orig_node,
  40                                  struct batadv_neigh_node *neigh_node)
  41 {
  42         struct batadv_neigh_node *curr_router;
  43
  44         curr_router = batadv_orig_node_get_router(orig_node);
  45
  46         /* route deleted */
  47         if ((curr_router) && (!neigh_node)) {
  48                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  49                            "Deleting route towards: %pM\n", orig_node->orig);
  50                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
  51                                           "Deleted route towards originator");
  52
  53         /* route added */
  54         } else if ((!curr_router) && (neigh_node)) {
  55                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  56                            "Adding route towards: %pM (via %pM)\n",
  57                            orig_node->orig, neigh_node->addr);
  58         /* route changed */
  59         } else if (neigh_node && curr_router) {
  60                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  61                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
  62                            orig_node->orig, neigh_node->addr,
  63                            curr_router->addr);
  64         }
  65
  66         if (curr_router)
  67                 batadv_neigh_node_free_ref(curr_router);
  68
  69         /* increase refcount of new best neighbor */
  70         if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
  71                 neigh_node = NULL;
  72
  73         spin_lock_bh(&orig_node->neigh_list_lock);
  74         rcu_assign_pointer(orig_node->router, neigh_node);
  75         spin_unlock_bh(&orig_node->neigh_list_lock);
  76
  77         /* decrease refcount of previous best neighbor */
  78         if (curr_router)
  79                 batadv_neigh_node_free_ref(curr_router);
  80 }
  81
  82 void batadv_update_route(struct batadv_priv *bat_priv,
  83                          struct batadv_orig_node *orig_node,
  84                          struct batadv_neigh_node *neigh_node)
  85 {
  86         struct batadv_neigh_node *router = NULL;
  87
  88         if (!orig_node)
  89                 goto out;
  90
  91         router = batadv_orig_node_get_router(orig_node);
  92
  93         if (router != neigh_node)
  94                 _batadv_update_route(bat_priv, orig_node, neigh_node);
  95
  96 out:
  97         if (router)
  98                 batadv_neigh_node_free_ref(router);
  99 }
 100
 101 /* caller must hold the neigh_list_lock */
 102 void batadv_bonding_candidate_del(struct batadv_orig_node *orig_node,
 103                                   struct batadv_neigh_node *neigh_node)
 104 {
 105         /* this neighbor is not part of our candidate list */
 106         if (list_empty(&neigh_node->bonding_list))
 107                 goto out;
 108
 109         list_del_rcu(&neigh_node->bonding_list);
 110         INIT_LIST_HEAD(&neigh_node->bonding_list);
 111         batadv_neigh_node_free_ref(neigh_node);
 112         atomic_dec(&orig_node->bond_candidates);
 113
 114 out:
 115         return;
 116 }
 117
 118 void batadv_bonding_candidate_add(struct batadv_orig_node *orig_node,
 119                                   struct batadv_neigh_node *neigh_node)
 120 {
 121         struct batadv_neigh_node *tmp_neigh_node, *router = NULL;
 122         uint8_t interference_candidate = 0, tq;
 123
 124         spin_lock_bh(&orig_node->neigh_list_lock);
 125
 126         /* only consider if it has the same primary address ...  */
 127         if (!batadv_compare_eth(orig_node->orig,
 128                                 neigh_node->orig_node->primary_addr))
 129                 goto candidate_del;
 130
 131         router = batadv_orig_node_get_router(orig_node);
 132         if (!router)
 133                 goto candidate_del;
 134
 135
 136         /* ... and is good enough to be considered */
 137         tq = router->bat_iv.tq_avg - BATADV_BONDING_TQ_THRESHOLD;
 138         if (neigh_node->bat_iv.tq_avg < tq)
 139                 goto candidate_del;
 140
 141         /* check if we have another candidate with the same mac address or
 142          * interface. If we do, we won't select this candidate because of
 143          * possible interference.
 144          */
 145         hlist_for_each_entry_rcu(tmp_neigh_node,
 146                                  &orig_node->neigh_list, list) {
 147                 if (tmp_neigh_node == neigh_node)
 148                         continue;
 149
 150                 /* we only care if the other candidate is even
 151                  * considered as candidate.
 152                  */
 153                 if (list_empty(&tmp_neigh_node->bonding_list))
 154                         continue;
 155
 156                 if ((neigh_node->if_incoming == tmp_neigh_node->if_incoming) ||
 157                     (batadv_compare_eth(neigh_node->addr,
 158                                         tmp_neigh_node->addr))) {
 159                         interference_candidate = 1;
 160                         break;
 161                 }
 162         }
 163
 164         /* don't care further if it is an interference candidate */
 165         if (interference_candidate)
 166                 goto candidate_del;
 167
 168         /* this neighbor already is part of our candidate list */
 169         if (!list_empty(&neigh_node->bonding_list))
 170                 goto out;
 171
 172         if (!atomic_inc_not_zero(&neigh_node->refcount))
 173                 goto out;
 174
 175         list_add_rcu(&neigh_node->bonding_list, &orig_node->bond_list);
 176         atomic_inc(&orig_node->bond_candidates);
 177         goto out;
 178
 179 candidate_del:
 180         batadv_bonding_candidate_del(orig_node, neigh_node);
 181
 182 out:
 183         spin_unlock_bh(&orig_node->neigh_list_lock);
 184
 185         if (router)
 186                 batadv_neigh_node_free_ref(router);
 187 }
 188
 189 /* copy primary address for bonding */
 190 void
 191 batadv_bonding_save_primary(const struct batadv_orig_node *orig_node,
 192                             struct batadv_orig_node *orig_neigh_node,
 193                             const struct batadv_ogm_packet *batman_ogm_packet)
 194 {
 195         if (!(batman_ogm_packet->flags & BATADV_PRIMARIES_FIRST_HOP))
 196                 return;
 197
 198         memcpy(orig_neigh_node->primary_addr, orig_node->orig, ETH_ALEN);
 199 }
 200
 201 /* checks whether the host restarted and is in the protection time.
 202  * returns:
 203  *  0 if the packet is to be accepted
 204  *  1 if the packet is to be ignored.
 205  */
 206 int batadv_window_protected(struct batadv_priv *bat_priv, int32_t seq_num_diff,
 207                             unsigned long *last_reset)
 208 {
 209         if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
 210             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 211                 if (!batadv_has_timed_out(*last_reset,
 212                                           BATADV_RESET_PROTECTION_MS))
 213                         return 1;
 214
 215                 *last_reset = jiffies;
 216                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 217                            "old packet received, start protection\n");
 218         }
 219
 220         return 0;
 221 }
 222
 223 bool batadv_check_management_packet(struct sk_buff *skb,
 224                                     struct batadv_hard_iface *hard_iface,
 225                                     int header_len)
 226 {
 227         struct ethhdr *ethhdr;
 228
 229         /* drop packet if it has not necessary minimum size */
 230         if (unlikely(!pskb_may_pull(skb, header_len)))
 231                 return false;
 232
 233         ethhdr = eth_hdr(skb);
 234
 235         /* packet with broadcast indication but unicast recipient */
 236         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 237                 return false;
 238
 239         /* packet with broadcast sender address */
 240         if (is_broadcast_ether_addr(ethhdr->h_source))
 241                 return false;
 242
 243         /* create a copy of the skb, if needed, to modify it. */
 244         if (skb_cow(skb, 0) < 0)
 245                 return false;
 246
 247         /* keep skb linear */
 248         if (skb_linearize(skb) < 0)
 249                 return false;
 250
 251         return true;
 252 }
 253
 254 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 255                                       struct sk_buff *skb, size_t icmp_len)
 256 {
 257         struct batadv_hard_iface *primary_if = NULL;
 258         struct batadv_orig_node *orig_node = NULL;
 259         struct batadv_icmp_packet_rr *icmp_packet;
 260         int ret = NET_RX_DROP;
 261
 262         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 263
 264         /* add data to device queue */
 265         if (icmp_packet->icmph.msg_type != BATADV_ECHO_REQUEST) {
 266                 batadv_socket_receive_packet(icmp_packet, icmp_len);
 267                 goto out;
 268         }
 269
 270         primary_if = batadv_primary_if_get_selected(bat_priv);
 271         if (!primary_if)
 272                 goto out;
 273
 274         /* answer echo request (ping) */
 275         /* get routing information */
 276         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->icmph.orig);
 277         if (!orig_node)
 278                 goto out;
 279
 280         /* create a copy of the skb, if needed, to modify it. */
 281         if (skb_cow(skb, ETH_HLEN) < 0)
 282                 goto out;
 283
 284         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 285
 286         memcpy(icmp_packet->icmph.dst, icmp_packet->icmph.orig, ETH_ALEN);
 287         memcpy(icmp_packet->icmph.orig, primary_if->net_dev->dev_addr,
 288                ETH_ALEN);
 289         icmp_packet->icmph.msg_type = BATADV_ECHO_REPLY;
 290         icmp_packet->icmph.header.ttl = BATADV_TTL;
 291
 292         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 293                 ret = NET_RX_SUCCESS;
 294
 295 out:
 296         if (primary_if)
 297                 batadv_hardif_free_ref(primary_if);
 298         if (orig_node)
 299                 batadv_orig_node_free_ref(orig_node);
 300         return ret;
 301 }
 302
 303 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 304                                          struct sk_buff *skb)
 305 {
 306         struct batadv_hard_iface *primary_if = NULL;
 307         struct batadv_orig_node *orig_node = NULL;
 308         struct batadv_icmp_packet *icmp_packet;
 309         int ret = NET_RX_DROP;
 310
 311         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 312
 313         /* send TTL exceeded if packet is an echo request (traceroute) */
 314         if (icmp_packet->icmph.msg_type != BATADV_ECHO_REQUEST) {
 315                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 316                          icmp_packet->icmph.orig, icmp_packet->icmph.dst);
 317                 goto out;
 318         }
 319
 320         primary_if = batadv_primary_if_get_selected(bat_priv);
 321         if (!primary_if)
 322                 goto out;
 323
 324         /* get routing information */
 325         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->icmph.orig);
 326         if (!orig_node)
 327                 goto out;
 328
 329         /* create a copy of the skb, if needed, to modify it. */
 330         if (skb_cow(skb, ETH_HLEN) < 0)
 331                 goto out;
 332
 333         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 334
 335         memcpy(icmp_packet->icmph.dst, icmp_packet->icmph.orig, ETH_ALEN);
 336         memcpy(icmp_packet->icmph.orig, primary_if->net_dev->dev_addr,
 337                ETH_ALEN);
 338         icmp_packet->icmph.msg_type = BATADV_TTL_EXCEEDED;
 339         icmp_packet->icmph.header.ttl = BATADV_TTL;
 340
 341         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 342                 ret = NET_RX_SUCCESS;
 343
 344 out:
 345         if (primary_if)
 346                 batadv_hardif_free_ref(primary_if);
 347         if (orig_node)
 348                 batadv_orig_node_free_ref(orig_node);
 349         return ret;
 350 }
 351
 352
 353 int batadv_recv_icmp_packet(struct sk_buff *skb,
 354                             struct batadv_hard_iface *recv_if)
 355 {
 356         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 357         struct batadv_icmp_packet_rr *icmp_packet;
 358         struct ethhdr *ethhdr;
 359         struct batadv_orig_node *orig_node = NULL;
 360         int hdr_size = sizeof(struct batadv_icmp_packet);
 361         int ret = NET_RX_DROP;
 362
 363         /* we truncate all incoming icmp packets if they don't match our size */
 364         if (skb->len >= sizeof(struct batadv_icmp_packet_rr))
 365                 hdr_size = sizeof(struct batadv_icmp_packet_rr);
 366
 367         /* drop packet if it has not necessary minimum size */
 368         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 369                 goto out;
 370
 371         ethhdr = eth_hdr(skb);
 372
 373         /* packet with unicast indication but broadcast recipient */
 374         if (is_broadcast_ether_addr(ethhdr->h_dest))
 375                 goto out;
 376
 377         /* packet with broadcast sender address */
 378         if (is_broadcast_ether_addr(ethhdr->h_source))
 379                 goto out;
 380
 381         /* not for me */
 382         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 383                 goto out;
 384
 385         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 386
 387         /* add record route information if not full */
 388         if ((icmp_packet->icmph.msg_type == BATADV_ECHO_REPLY ||
 389              icmp_packet->icmph.msg_type == BATADV_ECHO_REQUEST) &&
 390             (hdr_size == sizeof(struct batadv_icmp_packet_rr)) &&
 391             (icmp_packet->rr_cur < BATADV_RR_LEN)) {
 392                 memcpy(&(icmp_packet->rr[icmp_packet->rr_cur]),
 393                        ethhdr->h_dest, ETH_ALEN);
 394                 icmp_packet->rr_cur++;
 395         }
 396
 397         /* packet for me */
 398         if (batadv_is_my_mac(bat_priv, icmp_packet->icmph.dst))
 399                 return batadv_recv_my_icmp_packet(bat_priv, skb, hdr_size);
 400
 401         /* TTL exceeded */
 402         if (icmp_packet->icmph.header.ttl < 2)
 403                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 404
 405         /* get routing information */
 406         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->icmph.dst);
 407         if (!orig_node)
 408                 goto out;
 409
 410         /* create a copy of the skb, if needed, to modify it. */
 411         if (skb_cow(skb, ETH_HLEN) < 0)
 412                 goto out;
 413
 414         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 415
 416         /* decrement ttl */
 417         icmp_packet->icmph.header.ttl--;
 418
 419         /* route it */
 420         if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
 421                 ret = NET_RX_SUCCESS;
 422
 423 out:
 424         if (orig_node)
 425                 batadv_orig_node_free_ref(orig_node);
 426         return ret;
 427 }
 428
 429 /* In the bonding case, send the packets in a round
 430  * robin fashion over the remaining interfaces.
 431  *
 432  * This method rotates the bonding list and increases the
 433  * returned router's refcount.
 434  */
 435 static struct batadv_neigh_node *
 436 batadv_find_bond_router(struct batadv_orig_node *primary_orig,
 437                         const struct batadv_hard_iface *recv_if)
 438 {
 439         struct batadv_neigh_node *tmp_neigh_node;
 440         struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
 441
 442         rcu_read_lock();
 443         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 444                                 bonding_list) {
 445                 if (!first_candidate)
 446                         first_candidate = tmp_neigh_node;
 447
 448                 /* recv_if == NULL on the first node. */
 449                 if (tmp_neigh_node->if_incoming == recv_if)
 450                         continue;
 451
 452                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 453                         continue;
 454
 455                 router = tmp_neigh_node;
 456                 break;
 457         }
 458
 459         /* use the first candidate if nothing was found. */
 460         if (!router && first_candidate &&
 461             atomic_inc_not_zero(&first_candidate->refcount))
 462                 router = first_candidate;
 463
 464         if (!router)
 465                 goto out;
 466
 467         /* selected should point to the next element
 468          * after the current router
 469          */
 470         spin_lock_bh(&primary_orig->neigh_list_lock);
 471         /* this is a list_move(), which unfortunately
 472          * does not exist as rcu version
 473          */
 474         list_del_rcu(&primary_orig->bond_list);
 475         list_add_rcu(&primary_orig->bond_list,
 476                      &router->bonding_list);
 477         spin_unlock_bh(&primary_orig->neigh_list_lock);
 478
 479 out:
 480         rcu_read_unlock();
 481         return router;
 482 }
 483
 484 /* Interface Alternating: Use the best of the
 485  * remaining candidates which are not using
 486  * this interface.
 487  *
 488  * Increases the returned router's refcount
 489  */
 490 static struct batadv_neigh_node *
 491 batadv_find_ifalter_router(struct batadv_orig_node *primary_orig,
 492                            const struct batadv_hard_iface *recv_if)
 493 {
 494         struct batadv_neigh_node *tmp_neigh_node;
 495         struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
 496
 497         rcu_read_lock();
 498         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 499                                 bonding_list) {
 500                 if (!first_candidate)
 501                         first_candidate = tmp_neigh_node;
 502
 503                 /* recv_if == NULL on the first node. */
 504                 if (tmp_neigh_node->if_incoming == recv_if)
 505                         continue;
 506
 507                 if (router &&
 508                     tmp_neigh_node->bat_iv.tq_avg <= router->bat_iv.tq_avg)
 509                         continue;
 510
 511                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 512                         continue;
 513
 514                 /* decrement refcount of previously selected router */
 515                 if (router)
 516                         batadv_neigh_node_free_ref(router);
 517
 518                 /* we found a better router (or at least one valid router) */
 519                 router = tmp_neigh_node;
 520         }
 521
 522         /* use the first candidate if nothing was found. */
 523         if (!router && first_candidate &&
 524             atomic_inc_not_zero(&first_candidate->refcount))
 525                 router = first_candidate;
 526
 527         rcu_read_unlock();
 528         return router;
 529 }
 530
 531 /**
 532  * batadv_check_unicast_packet - Check for malformed unicast packets
 533  * @bat_priv: the bat priv with all the soft interface information
 534  * @skb: packet to check
 535  * @hdr_size: size of header to pull
 536  *
 537  * Check for short header and bad addresses in given packet. Returns negative
 538  * value when check fails and 0 otherwise. The negative value depends on the
 539  * reason: -ENODATA for bad header, -EBADR for broadcast destination or source,
 540  * and -EREMOTE for non-local (other host) destination.
 541  */
 542 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 543                                        struct sk_buff *skb, int hdr_size)
 544 {
 545         struct ethhdr *ethhdr;
 546
 547         /* drop packet if it has not necessary minimum size */
 548         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 549                 return -ENODATA;
 550
 551         ethhdr = eth_hdr(skb);
 552
 553         /* packet with unicast indication but broadcast recipient */
 554         if (is_broadcast_ether_addr(ethhdr->h_dest))
 555                 return -EBADR;
 556
 557         /* packet with broadcast sender address */
 558         if (is_broadcast_ether_addr(ethhdr->h_source))
 559                 return -EBADR;
 560
 561         /* not for me */
 562         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 563                 return -EREMOTE;
 564
 565         return 0;
 566 }
 567
 568 /* find a suitable router for this originator, and use
 569  * bonding if possible. increases the found neighbors
 570  * refcount.
 571  */
 572 struct batadv_neigh_node *
 573 batadv_find_router(struct batadv_priv *bat_priv,
 574                    struct batadv_orig_node *orig_node,
 575                    const struct batadv_hard_iface *recv_if)
 576 {
 577         struct batadv_orig_node *primary_orig_node;
 578         struct batadv_orig_node *router_orig;
 579         struct batadv_neigh_node *router;
 580         static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
 581         int bonding_enabled;
 582         uint8_t *primary_addr;
 583
 584         if (!orig_node)
 585                 return NULL;
 586
 587         router = batadv_orig_node_get_router(orig_node);
 588         if (!router)
 589                 goto err;
 590
 591         /* without bonding, the first node should
 592          * always choose the default router.
 593          */
 594         bonding_enabled = atomic_read(&bat_priv->bonding);
 595
 596         rcu_read_lock();
 597         /* select default router to output */
 598         router_orig = router->orig_node;
 599         if (!router_orig)
 600                 goto err_unlock;
 601
 602         if ((!recv_if) && (!bonding_enabled))
 603                 goto return_router;
 604
 605         primary_addr = router_orig->primary_addr;
 606
 607         /* if we have something in the primary_addr, we can search
 608          * for a potential bonding candidate.
 609          */
 610         if (batadv_compare_eth(primary_addr, zero_mac))
 611                 goto return_router;
 612
 613         /* find the orig_node which has the primary interface. might
 614          * even be the same as our router_orig in many cases
 615          */
 616         if (batadv_compare_eth(primary_addr, router_orig->orig)) {
 617                 primary_orig_node = router_orig;
 618         } else {
 619                 primary_orig_node = batadv_orig_hash_find(bat_priv,
 620                                                           primary_addr);
 621                 if (!primary_orig_node)
 622                         goto return_router;
 623
 624                 batadv_orig_node_free_ref(primary_orig_node);
 625         }
 626
 627         /* with less than 2 candidates, we can't do any
 628          * bonding and prefer the original router.
 629          */
 630         if (atomic_read(&primary_orig_node->bond_candidates) < 2)
 631                 goto return_router;
 632
 633         /* all nodes between should choose a candidate which
 634          * is is not on the interface where the packet came
 635          * in.
 636          */
 637         batadv_neigh_node_free_ref(router);
 638
 639         if (bonding_enabled)
 640                 router = batadv_find_bond_router(primary_orig_node, recv_if);
 641         else
 642                 router = batadv_find_ifalter_router(primary_orig_node, recv_if);
 643
 644 return_router:
 645         if (router && router->if_incoming->if_status != BATADV_IF_ACTIVE)
 646                 goto err_unlock;
 647
 648         rcu_read_unlock();
 649         return router;
 650 err_unlock:
 651         rcu_read_unlock();
 652 err:
 653         if (router)
 654                 batadv_neigh_node_free_ref(router);
 655         return NULL;
 656 }
 657
 658 static int batadv_route_unicast_packet(struct sk_buff *skb,
 659                                        struct batadv_hard_iface *recv_if)
 660 {
 661         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 662         struct batadv_orig_node *orig_node = NULL;
 663         struct batadv_unicast_packet *unicast_packet;
 664         struct ethhdr *ethhdr = eth_hdr(skb);
 665         int res, hdr_len, ret = NET_RX_DROP;
 666
 667         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 668
 669         /* TTL exceeded */
 670         if (unicast_packet->header.ttl < 2) {
 671                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 672                          ethhdr->h_source, unicast_packet->dest);
 673                 goto out;
 674         }
 675
 676         /* get routing information */
 677         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 678
 679         if (!orig_node)
 680                 goto out;
 681
 682         /* create a copy of the skb, if needed, to modify it. */
 683         if (skb_cow(skb, ETH_HLEN) < 0)
 684                 goto out;
 685
 686         /* decrement ttl */
 687         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 688         unicast_packet->header.ttl--;
 689
 690         switch (unicast_packet->header.packet_type) {
 691         case BATADV_UNICAST_4ADDR:
 692                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 693                 break;
 694         case BATADV_UNICAST:
 695                 hdr_len = sizeof(struct batadv_unicast_packet);
 696                 break;
 697         default:
 698                 /* other packet types not supported - yet */
 699                 hdr_len = -1;
 700                 break;
 701         }
 702
 703         if (hdr_len > 0)
 704                 batadv_skb_set_priority(skb, hdr_len);
 705
 706         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 707
 708         /* translate transmit result into receive result */
 709         if (res == NET_XMIT_SUCCESS) {
 710                 /* skb was transmitted and consumed */
 711                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 712                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 713                                    skb->len + ETH_HLEN);
 714
 715                 ret = NET_RX_SUCCESS;
 716         } else if (res == NET_XMIT_POLICED) {
 717                 /* skb was buffered and consumed */
 718                 ret = NET_RX_SUCCESS;
 719         }
 720
 721 out:
 722         if (orig_node)
 723                 batadv_orig_node_free_ref(orig_node);
 724         return ret;
 725 }
 726
 727 /**
 728  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 729  * @bat_priv: the bat priv with all the soft interface information
 730  * @unicast_packet: the unicast header to be updated
 731  * @dst_addr: the payload destination
 732  * @vid: VLAN identifier
 733  *
 734  * Search the translation table for dst_addr and update the unicast header with
 735  * the new corresponding information (originator address where the destination
 736  * client currently is and its known TTVN)
 737  *
 738  * Returns true if the packet header has been updated, false otherwise
 739  */
 740 static bool
 741 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 742                               struct batadv_unicast_packet *unicast_packet,
 743                               uint8_t *dst_addr, unsigned short vid)
 744 {
 745         struct batadv_orig_node *orig_node = NULL;
 746         struct batadv_hard_iface *primary_if = NULL;
 747         bool ret = false;
 748         uint8_t *orig_addr, orig_ttvn;
 749
 750         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 751                 primary_if = batadv_primary_if_get_selected(bat_priv);
 752                 if (!primary_if)
 753                         goto out;
 754                 orig_addr = primary_if->net_dev->dev_addr;
 755                 orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 756         } else {
 757                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 758                                                      vid);
 759                 if (!orig_node)
 760                         goto out;
 761
 762                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 763                         goto out;
 764
 765                 orig_addr = orig_node->orig;
 766                 orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 767         }
 768
 769         /* update the packet header */
 770         memcpy(unicast_packet->dest, orig_addr, ETH_ALEN);
 771         unicast_packet->ttvn = orig_ttvn;
 772
 773         ret = true;
 774 out:
 775         if (primary_if)
 776                 batadv_hardif_free_ref(primary_if);
 777         if (orig_node)
 778                 batadv_orig_node_free_ref(orig_node);
 779
 780         return ret;
 781 }
 782
 783 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 784                                      struct sk_buff *skb, int hdr_len) {
 785         struct batadv_unicast_packet *unicast_packet;
 786         struct batadv_hard_iface *primary_if;
 787         struct batadv_orig_node *orig_node;
 788         uint8_t curr_ttvn, old_ttvn;
 789         struct ethhdr *ethhdr;
 790         unsigned short vid;
 791         int is_old_ttvn;
 792
 793         /* check if there is enough data before accessing it */
 794         if (pskb_may_pull(skb, hdr_len + ETH_HLEN) < 0)
 795                 return 0;
 796
 797         /* create a copy of the skb (in case of for re-routing) to modify it. */
 798         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 799                 return 0;
 800
 801         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 802         vid = batadv_get_vid(skb, hdr_len);
 803         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 804
 805         /* check if the destination client was served by this node and it is now
 806          * roaming. In this case, it means that the node has got a ROAM_ADV
 807          * message and that it knows the new destination in the mesh to re-route
 808          * the packet to
 809          */
 810         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 811                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 812                                                   ethhdr->h_dest, vid))
 813                         net_ratelimited_function(batadv_dbg, BATADV_DBG_TT,
 814                                                  bat_priv,
 815                                                  "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 816                                                  unicast_packet->dest,
 817                                                  ethhdr->h_dest);
 818                 /* at this point the mesh destination should have been
 819                  * substituted with the originator address found in the global
 820                  * table. If not, let the packet go untouched anyway because
 821                  * there is nothing the node can do
 822                  */
 823                 return 1;
 824         }
 825
 826         /* retrieve the TTVN known by this node for the packet destination. This
 827          * value is used later to check if the node which sent (or re-routed
 828          * last time) the packet had an updated information or not
 829          */
 830         curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 831         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 832                 orig_node = batadv_orig_hash_find(bat_priv,
 833                                                   unicast_packet->dest);
 834                 /* if it is not possible to find the orig_node representing the
 835                  * destination, the packet can immediately be dropped as it will
 836                  * not be possible to deliver it
 837                  */
 838                 if (!orig_node)
 839                         return 0;
 840
 841                 curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 842                 batadv_orig_node_free_ref(orig_node);
 843         }
 844
 845         /* check if the TTVN contained in the packet is fresher than what the
 846          * node knows
 847          */
 848         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 849         if (!is_old_ttvn)
 850                 return 1;
 851
 852         old_ttvn = unicast_packet->ttvn;
 853         /* the packet was forged based on outdated network information. Its
 854          * destination can possibly be updated and forwarded towards the new
 855          * target host
 856          */
 857         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 858                                           ethhdr->h_dest, vid)) {
 859                 net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv,
 860                                          "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 861                                          unicast_packet->dest, ethhdr->h_dest,
 862                                          old_ttvn, curr_ttvn);
 863                 return 1;
 864         }
 865
 866         /* the packet has not been re-routed: either the destination is
 867          * currently served by this node or there is no destination at all and
 868          * it is possible to drop the packet
 869          */
 870         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 871                 return 0;
 872
 873         /* update the header in order to let the packet be delivered to this
 874          * node's soft interface
 875          */
 876         primary_if = batadv_primary_if_get_selected(bat_priv);
 877         if (!primary_if)
 878                 return 0;
 879
 880         memcpy(unicast_packet->dest, primary_if->net_dev->dev_addr, ETH_ALEN);
 881
 882         batadv_hardif_free_ref(primary_if);
 883
 884         unicast_packet->ttvn = curr_ttvn;
 885
 886         return 1;
 887 }
 888
 889 /**
 890  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 891  *      are in the unicast number space but not yet known to the implementation
 892  * @skb: unicast tvlv packet to process
 893  * @recv_if: pointer to interface this packet was received on
 894  *
 895  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 896  * otherwise.
 897  */
 898 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 899                                          struct batadv_hard_iface *recv_if)
 900 {
 901         struct batadv_unicast_packet *unicast_packet;
 902         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 903         int check, hdr_size = sizeof(*unicast_packet);
 904
 905         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 906         if (check < 0)
 907                 return NET_RX_DROP;
 908
 909         /* we don't know about this type, drop it. */
 910         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 911         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 912                 return NET_RX_DROP;
 913
 914         return batadv_route_unicast_packet(skb, recv_if);
 915 }
 916
 917 int batadv_recv_unicast_packet(struct sk_buff *skb,
 918                                struct batadv_hard_iface *recv_if)
 919 {
 920         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 921         struct batadv_unicast_packet *unicast_packet;
 922         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 923         uint8_t *orig_addr;
 924         struct batadv_orig_node *orig_node = NULL;
 925         int check, hdr_size = sizeof(*unicast_packet);
 926         bool is4addr;
 927
 928         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 929         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 930
 931         is4addr = unicast_packet->header.packet_type == BATADV_UNICAST_4ADDR;
 932         /* the caller function should have already pulled 2 bytes */
 933         if (is4addr)
 934                 hdr_size = sizeof(*unicast_4addr_packet);
 935
 936         /* function returns -EREMOTE for promiscuous packets */
 937         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 938
 939         /* Even though the packet is not for us, we might save it to use for
 940          * decoding a later received coded packet
 941          */
 942         if (check == -EREMOTE)
 943                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 944
 945         if (check < 0)
 946                 return NET_RX_DROP;
 947         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 948                 return NET_RX_DROP;
 949
 950         /* packet for me */
 951         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 952                 if (is4addr) {
 953                         batadv_dat_inc_counter(bat_priv,
 954                                                unicast_4addr_packet->subtype);
 955                         orig_addr = unicast_4addr_packet->src;
 956                         orig_node = batadv_orig_hash_find(bat_priv, orig_addr);
 957                 }
 958
 959                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 960                                                           hdr_size))
 961                         goto rx_success;
 962                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 963                                                         hdr_size))
 964                         goto rx_success;
 965
 966                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
 967                                     orig_node);
 968
 969 rx_success:
 970                 if (orig_node)
 971                         batadv_orig_node_free_ref(orig_node);
 972
 973                 return NET_RX_SUCCESS;
 974         }
 975
 976         return batadv_route_unicast_packet(skb, recv_if);
 977 }
 978
 979 /**
 980  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
 981  * @skb: unicast tvlv packet to process
 982  * @recv_if: pointer to interface this packet was received on
 983  * @dst_addr: the payload destination
 984  *
 985  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 986  * otherwise.
 987  */
 988 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
 989                              struct batadv_hard_iface *recv_if)
 990 {
 991         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 992         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
 993         unsigned char *tvlv_buff;
 994         uint16_t tvlv_buff_len;
 995         int hdr_size = sizeof(*unicast_tvlv_packet);
 996         int ret = NET_RX_DROP;
 997
 998         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
 999                 return NET_RX_DROP;
1000
1001         /* the header is likely to be modified while forwarding */
1002         if (skb_cow(skb, hdr_size) < 0)
1003                 return NET_RX_DROP;
1004
1005         /* packet needs to be linearized to access the tvlv content */
1006         if (skb_linearize(skb) < 0)
1007                 return NET_RX_DROP;
1008
1009         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
1010
1011         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1012         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
1013
1014         if (tvlv_buff_len > skb->len - hdr_size)
1015                 return NET_RX_DROP;
1016
1017         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
1018                                              unicast_tvlv_packet->src,
1019                                              unicast_tvlv_packet->dst,
1020                                              tvlv_buff, tvlv_buff_len);
1021
1022         if (ret != NET_RX_SUCCESS)
1023                 ret = batadv_route_unicast_packet(skb, recv_if);
1024
1025         return ret;
1026 }
1027
1028 /**
1029  * batadv_recv_frag_packet - process received fragment
1030  * @skb: the received fragment
1031  * @recv_if: interface that the skb is received on
1032  *
1033  * This function does one of the three following things: 1) Forward fragment, if
1034  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
1035  * lack further fragments; 3) Merge fragments, if we have all needed parts.
1036  *
1037  * Return NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1038  */
1039 int batadv_recv_frag_packet(struct sk_buff *skb,
1040                             struct batadv_hard_iface *recv_if)
1041 {
1042         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1043         struct batadv_orig_node *orig_node_src = NULL;
1044         struct batadv_frag_packet *frag_packet;
1045         int ret = NET_RX_DROP;
1046
1047         if (batadv_check_unicast_packet(bat_priv, skb,
1048                                         sizeof(*frag_packet)) < 0)
1049                 goto out;
1050
1051         frag_packet = (struct batadv_frag_packet *)skb->data;
1052         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1053         if (!orig_node_src)
1054                 goto out;
1055
1056         /* Route the fragment if it is not for us and too big to be merged. */
1057         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1058             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1059                 ret = NET_RX_SUCCESS;
1060                 goto out;
1061         }
1062
1063         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1064         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1065
1066         /* Add fragment to buffer and merge if possible. */
1067         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1068                 goto out;
1069
1070         /* Deliver merged packet to the appropriate handler, if it was
1071          * merged
1072          */
1073         if (skb)
1074                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1075                                        &recv_if->batman_adv_ptype, NULL);
1076
1077         ret = NET_RX_SUCCESS;
1078
1079 out:
1080         if (orig_node_src)
1081                 batadv_orig_node_free_ref(orig_node_src);
1082
1083         return ret;
1084 }
1085
1086 int batadv_recv_bcast_packet(struct sk_buff *skb,
1087                              struct batadv_hard_iface *recv_if)
1088 {
1089         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1090         struct batadv_orig_node *orig_node = NULL;
1091         struct batadv_bcast_packet *bcast_packet;
1092         struct ethhdr *ethhdr;
1093         int hdr_size = sizeof(*bcast_packet);
1094         int ret = NET_RX_DROP;
1095         int32_t seq_diff;
1096
1097         /* drop packet if it has not necessary minimum size */
1098         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1099                 goto out;
1100
1101         ethhdr = eth_hdr(skb);
1102
1103         /* packet with broadcast indication but unicast recipient */
1104         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1105                 goto out;
1106
1107         /* packet with broadcast sender address */
1108         if (is_broadcast_ether_addr(ethhdr->h_source))
1109                 goto out;
1110
1111         /* ignore broadcasts sent by myself */
1112         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1113                 goto out;
1114
1115         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1116
1117         /* ignore broadcasts originated by myself */
1118         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1119                 goto out;
1120
1121         if (bcast_packet->header.ttl < 2)
1122                 goto out;
1123
1124         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1125
1126         if (!orig_node)
1127                 goto out;
1128
1129         spin_lock_bh(&orig_node->bcast_seqno_lock);
1130
1131         /* check whether the packet is a duplicate */
1132         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1133                             ntohl(bcast_packet->seqno)))
1134                 goto spin_unlock;
1135
1136         seq_diff = ntohl(bcast_packet->seqno) - orig_node->last_bcast_seqno;
1137
1138         /* check whether the packet is old and the host just restarted. */
1139         if (batadv_window_protected(bat_priv, seq_diff,
1140                                     &orig_node->bcast_seqno_reset))
1141                 goto spin_unlock;
1142
1143         /* mark broadcast in flood history, update window position
1144          * if required.
1145          */
1146         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1147                 orig_node->last_bcast_seqno = ntohl(bcast_packet->seqno);
1148
1149         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1150
1151         /* check whether this has been sent by another originator before */
1152         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1153                 goto out;
1154
1155         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1156
1157         /* rebroadcast packet */
1158         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1159
1160         /* don't hand the broadcast up if it is from an originator
1161          * from the same backbone.
1162          */
1163         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1164                 goto out;
1165
1166         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1167                 goto rx_success;
1168         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1169                 goto rx_success;
1170
1171         /* broadcast for me */
1172         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1173                             orig_node);
1174
1175 rx_success:
1176         ret = NET_RX_SUCCESS;
1177         goto out;
1178
1179 spin_unlock:
1180         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1181 out:
1182         if (orig_node)
1183                 batadv_orig_node_free_ref(orig_node);
1184         return ret;
1185 }