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