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