net/batman-adv/routing.c

   1 /* Copyright (C) 2007-2013 B.A.T.M.A.N. contributors:
   2  *
   3  * Marek Lindner, Simon Wunderlich
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 2 of the GNU General Public
   7  * License as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA
  18  */
  19
  20 #include "main.h"
  21 #include "routing.h"
  22 #include "send.h"
  23 #include "soft-interface.h"
  24 #include "hard-interface.h"
  25 #include "icmp_socket.h"
  26 #include "translation-table.h"
  27 #include "originator.h"
  28 #include "bridge_loop_avoidance.h"
  29 #include "distributed-arp-table.h"
  30 #include "network-coding.h"
  31 #include "fragmentation.h"
  32
  33 #include <linux/if_vlan.h>
  34
  35 static int batadv_route_unicast_packet(struct sk_buff *skb,
  36                                        struct batadv_hard_iface *recv_if);
  37
  38 static void _batadv_update_route(struct batadv_priv *bat_priv,
  39                                  struct batadv_orig_node *orig_node,
  40                                  struct batadv_neigh_node *neigh_node)
  41 {
  42         struct batadv_neigh_node *curr_router;
  43
  44         curr_router = batadv_orig_node_get_router(orig_node);
  45
  46         /* route deleted */
  47         if ((curr_router) && (!neigh_node)) {
  48                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  49                            "Deleting route towards: %pM\n", orig_node->orig);
  50                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
  51                                           "Deleted route towards originator");
  52
  53         /* route added */
  54         } else if ((!curr_router) && (neigh_node)) {
  55                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  56                            "Adding route towards: %pM (via %pM)\n",
  57                            orig_node->orig, neigh_node->addr);
  58         /* route changed */
  59         } else if (neigh_node && curr_router) {
  60                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  61                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
  62                            orig_node->orig, neigh_node->addr,
  63                            curr_router->addr);
  64         }
  65
  66         if (curr_router)
  67                 batadv_neigh_node_free_ref(curr_router);
  68
  69         /* increase refcount of new best neighbor */
  70         if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
  71                 neigh_node = NULL;
  72
  73         spin_lock_bh(&orig_node->neigh_list_lock);
  74         rcu_assign_pointer(orig_node->router, neigh_node);
  75         spin_unlock_bh(&orig_node->neigh_list_lock);
  76
  77         /* decrease refcount of previous best neighbor */
  78         if (curr_router)
  79                 batadv_neigh_node_free_ref(curr_router);
  80 }
  81
  82 void batadv_update_route(struct batadv_priv *bat_priv,
  83                          struct batadv_orig_node *orig_node,
  84                          struct batadv_neigh_node *neigh_node)
  85 {
  86         struct batadv_neigh_node *router = NULL;
  87
  88         if (!orig_node)
  89                 goto out;
  90
  91         router = batadv_orig_node_get_router(orig_node);
  92
  93         if (router != neigh_node)
  94                 _batadv_update_route(bat_priv, orig_node, neigh_node);
  95
  96 out:
  97         if (router)
  98                 batadv_neigh_node_free_ref(router);
  99 }
 100
 101 /* caller must hold the neigh_list_lock */
 102 void batadv_bonding_candidate_del(struct batadv_orig_node *orig_node,
 103                                   struct batadv_neigh_node *neigh_node)
 104 {
 105         /* this neighbor is not part of our candidate list */
 106         if (list_empty(&neigh_node->bonding_list))
 107                 goto out;
 108
 109         list_del_rcu(&neigh_node->bonding_list);
 110         INIT_LIST_HEAD(&neigh_node->bonding_list);
 111         batadv_neigh_node_free_ref(neigh_node);
 112         atomic_dec(&orig_node->bond_candidates);
 113
 114 out:
 115         return;
 116 }
 117
 118 /**
 119  * batadv_bonding_candidate_add - consider a new link for bonding mode towards
 120  *  the given originator
 121  * @bat_priv: the bat priv with all the soft interface information
 122  * @orig_node: the target node
 123  * @neigh_node: the neighbor representing the new link to consider for bonding
 124  *  mode
 125  */
 126 void batadv_bonding_candidate_add(struct batadv_priv *bat_priv,
 127                                   struct batadv_orig_node *orig_node,
 128                                   struct batadv_neigh_node *neigh_node)
 129 {
 130         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 131         struct batadv_neigh_node *tmp_neigh_node, *router = NULL;
 132         uint8_t interference_candidate = 0;
 133
 134         spin_lock_bh(&orig_node->neigh_list_lock);
 135
 136         /* only consider if it has the same primary address ...  */
 137         if (!batadv_compare_eth(orig_node->orig,
 138                                 neigh_node->orig_node->primary_addr))
 139                 goto candidate_del;
 140
 141         router = batadv_orig_node_get_router(orig_node);
 142         if (!router)
 143                 goto candidate_del;
 144
 145
 146         /* ... and is good enough to be considered */
 147         if (bao->bat_neigh_is_equiv_or_better(neigh_node, router))
 148                 goto candidate_del;
 149
 150         /* check if we have another candidate with the same mac address or
 151          * interface. If we do, we won't select this candidate because of
 152          * possible interference.
 153          */
 154         hlist_for_each_entry_rcu(tmp_neigh_node,
 155                                  &orig_node->neigh_list, list) {
 156                 if (tmp_neigh_node == neigh_node)
 157                         continue;
 158
 159                 /* we only care if the other candidate is even
 160                  * considered as candidate.
 161                  */
 162                 if (list_empty(&tmp_neigh_node->bonding_list))
 163                         continue;
 164
 165                 if ((neigh_node->if_incoming == tmp_neigh_node->if_incoming) ||
 166                     (batadv_compare_eth(neigh_node->addr,
 167                                         tmp_neigh_node->addr))) {
 168                         interference_candidate = 1;
 169                         break;
 170                 }
 171         }
 172
 173         /* don't care further if it is an interference candidate */
 174         if (interference_candidate)
 175                 goto candidate_del;
 176
 177         /* this neighbor already is part of our candidate list */
 178         if (!list_empty(&neigh_node->bonding_list))
 179                 goto out;
 180
 181         if (!atomic_inc_not_zero(&neigh_node->refcount))
 182                 goto out;
 183
 184         list_add_rcu(&neigh_node->bonding_list, &orig_node->bond_list);
 185         atomic_inc(&orig_node->bond_candidates);
 186         goto out;
 187
 188 candidate_del:
 189         batadv_bonding_candidate_del(orig_node, neigh_node);
 190
 191 out:
 192         spin_unlock_bh(&orig_node->neigh_list_lock);
 193
 194         if (router)
 195                 batadv_neigh_node_free_ref(router);
 196 }
 197
 198 /* copy primary address for bonding */
 199 void
 200 batadv_bonding_save_primary(const struct batadv_orig_node *orig_node,
 201                             struct batadv_orig_node *orig_neigh_node,
 202                             const struct batadv_ogm_packet *batman_ogm_packet)
 203 {
 204         if (!(batman_ogm_packet->flags & BATADV_PRIMARIES_FIRST_HOP))
 205                 return;
 206
 207         memcpy(orig_neigh_node->primary_addr, orig_node->orig, ETH_ALEN);
 208 }
 209
 210 /* checks whether the host restarted and is in the protection time.
 211  * returns:
 212  *  0 if the packet is to be accepted
 213  *  1 if the packet is to be ignored.
 214  */
 215 int batadv_window_protected(struct batadv_priv *bat_priv, int32_t seq_num_diff,
 216                             unsigned long *last_reset)
 217 {
 218         if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
 219             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 220                 if (!batadv_has_timed_out(*last_reset,
 221                                           BATADV_RESET_PROTECTION_MS))
 222                         return 1;
 223
 224                 *last_reset = jiffies;
 225                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 226                            "old packet received, start protection\n");
 227         }
 228
 229         return 0;
 230 }
 231
 232 bool batadv_check_management_packet(struct sk_buff *skb,
 233                                     struct batadv_hard_iface *hard_iface,
 234                                     int header_len)
 235 {
 236         struct ethhdr *ethhdr;
 237
 238         /* drop packet if it has not necessary minimum size */
 239         if (unlikely(!pskb_may_pull(skb, header_len)))
 240                 return false;
 241
 242         ethhdr = eth_hdr(skb);
 243
 244         /* packet with broadcast indication but unicast recipient */
 245         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 246                 return false;
 247
 248         /* packet with broadcast sender address */
 249         if (is_broadcast_ether_addr(ethhdr->h_source))
 250                 return false;
 251
 252         /* create a copy of the skb, if needed, to modify it. */
 253         if (skb_cow(skb, 0) < 0)
 254                 return false;
 255
 256         /* keep skb linear */
 257         if (skb_linearize(skb) < 0)
 258                 return false;
 259
 260         return true;
 261 }
 262
 263 /**
 264  * batadv_recv_my_icmp_packet - receive an icmp packet locally
 265  * @bat_priv: the bat priv with all the soft interface information
 266  * @skb: icmp packet to process
 267  *
 268  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 269  * otherwise.
 270  */
 271 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 272                                       struct sk_buff *skb)
 273 {
 274         struct batadv_hard_iface *primary_if = NULL;
 275         struct batadv_orig_node *orig_node = NULL;
 276         struct batadv_icmp_header *icmph;
 277         int res, ret = NET_RX_DROP;
 278
 279         icmph = (struct batadv_icmp_header *)skb->data;
 280
 281         switch (icmph->msg_type) {
 282         case BATADV_ECHO_REPLY:
 283         case BATADV_DESTINATION_UNREACHABLE:
 284         case BATADV_TTL_EXCEEDED:
 285                 /* receive the packet */
 286                 if (skb_linearize(skb) < 0)
 287                         break;
 288
 289                 batadv_socket_receive_packet(icmph, skb->len);
 290                 break;
 291         case BATADV_ECHO_REQUEST:
 292                 /* answer echo request (ping) */
 293                 primary_if = batadv_primary_if_get_selected(bat_priv);
 294                 if (!primary_if)
 295                         goto out;
 296
 297                 /* get routing information */
 298                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 299                 if (!orig_node)
 300                         goto out;
 301
 302                 /* create a copy of the skb, if needed, to modify it. */
 303                 if (skb_cow(skb, ETH_HLEN) < 0)
 304                         goto out;
 305
 306                 icmph = (struct batadv_icmp_header *)skb->data;
 307
 308                 memcpy(icmph->dst, icmph->orig, ETH_ALEN);
 309                 memcpy(icmph->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 310                 icmph->msg_type = BATADV_ECHO_REPLY;
 311                 icmph->header.ttl = BATADV_TTL;
 312
 313                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 314                 if (res != NET_XMIT_DROP)
 315                         ret = NET_RX_SUCCESS;
 316
 317                 break;
 318         default:
 319                 /* drop unknown type */
 320                 goto out;
 321         }
 322 out:
 323         if (primary_if)
 324                 batadv_hardif_free_ref(primary_if);
 325         if (orig_node)
 326                 batadv_orig_node_free_ref(orig_node);
 327         return ret;
 328 }
 329
 330 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 331                                          struct sk_buff *skb)
 332 {
 333         struct batadv_hard_iface *primary_if = NULL;
 334         struct batadv_orig_node *orig_node = NULL;
 335         struct batadv_icmp_packet *icmp_packet;
 336         int ret = NET_RX_DROP;
 337
 338         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 339
 340         /* send TTL exceeded if packet is an echo request (traceroute) */
 341         if (icmp_packet->icmph.msg_type != BATADV_ECHO_REQUEST) {
 342                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 343                          icmp_packet->icmph.orig, icmp_packet->icmph.dst);
 344                 goto out;
 345         }
 346
 347         primary_if = batadv_primary_if_get_selected(bat_priv);
 348         if (!primary_if)
 349                 goto out;
 350
 351         /* get routing information */
 352         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->icmph.orig);
 353         if (!orig_node)
 354                 goto out;
 355
 356         /* create a copy of the skb, if needed, to modify it. */
 357         if (skb_cow(skb, ETH_HLEN) < 0)
 358                 goto out;
 359
 360         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 361
 362         memcpy(icmp_packet->icmph.dst, icmp_packet->icmph.orig, ETH_ALEN);
 363         memcpy(icmp_packet->icmph.orig, primary_if->net_dev->dev_addr,
 364                ETH_ALEN);
 365         icmp_packet->icmph.msg_type = BATADV_TTL_EXCEEDED;
 366         icmp_packet->icmph.header.ttl = BATADV_TTL;
 367
 368         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 369                 ret = NET_RX_SUCCESS;
 370
 371 out:
 372         if (primary_if)
 373                 batadv_hardif_free_ref(primary_if);
 374         if (orig_node)
 375                 batadv_orig_node_free_ref(orig_node);
 376         return ret;
 377 }
 378
 379
 380 int batadv_recv_icmp_packet(struct sk_buff *skb,
 381                             struct batadv_hard_iface *recv_if)
 382 {
 383         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 384         struct batadv_icmp_header *icmph;
 385         struct batadv_icmp_packet_rr *icmp_packet_rr;
 386         struct ethhdr *ethhdr;
 387         struct batadv_orig_node *orig_node = NULL;
 388         int hdr_size = sizeof(struct batadv_icmp_header);
 389         int ret = NET_RX_DROP;
 390
 391         /* drop packet if it has not necessary minimum size */
 392         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 393                 goto out;
 394
 395         ethhdr = eth_hdr(skb);
 396
 397         /* packet with unicast indication but broadcast recipient */
 398         if (is_broadcast_ether_addr(ethhdr->h_dest))
 399                 goto out;
 400
 401         /* packet with broadcast sender address */
 402         if (is_broadcast_ether_addr(ethhdr->h_source))
 403                 goto out;
 404
 405         /* not for me */
 406         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 407                 goto out;
 408
 409         icmph = (struct batadv_icmp_header *)skb->data;
 410
 411         /* add record route information if not full */
 412         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 413              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 414             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 415                 if (skb_linearize(skb) < 0)
 416                         goto out;
 417
 418                 /* create a copy of the skb, if needed, to modify it. */
 419                 if (skb_cow(skb, ETH_HLEN) < 0)
 420                         goto out;
 421
 422                 icmph = (struct batadv_icmp_header *)skb->data;
 423                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 424                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 425                         goto out;
 426
 427                 memcpy(&(icmp_packet_rr->rr[icmp_packet_rr->rr_cur]),
 428                        ethhdr->h_dest, ETH_ALEN);
 429                 icmp_packet_rr->rr_cur++;
 430         }
 431
 432         /* packet for me */
 433         if (batadv_is_my_mac(bat_priv, icmph->dst))
 434                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 435
 436         /* TTL exceeded */
 437         if (icmph->header.ttl < 2)
 438                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 439
 440         /* get routing information */
 441         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 442         if (!orig_node)
 443                 goto out;
 444
 445         /* create a copy of the skb, if needed, to modify it. */
 446         if (skb_cow(skb, ETH_HLEN) < 0)
 447                 goto out;
 448
 449         icmph = (struct batadv_icmp_header *)skb->data;
 450
 451         /* decrement ttl */
 452         icmph->header.ttl--;
 453
 454         /* route it */
 455         if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
 456                 ret = NET_RX_SUCCESS;
 457
 458 out:
 459         if (orig_node)
 460                 batadv_orig_node_free_ref(orig_node);
 461         return ret;
 462 }
 463
 464 /* In the bonding case, send the packets in a round
 465  * robin fashion over the remaining interfaces.
 466  *
 467  * This method rotates the bonding list and increases the
 468  * returned router's refcount.
 469  */
 470 static struct batadv_neigh_node *
 471 batadv_find_bond_router(struct batadv_orig_node *primary_orig,
 472                         const struct batadv_hard_iface *recv_if)
 473 {
 474         struct batadv_neigh_node *tmp_neigh_node;
 475         struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
 476
 477         rcu_read_lock();
 478         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 479                                 bonding_list) {
 480                 if (!first_candidate)
 481                         first_candidate = tmp_neigh_node;
 482
 483                 /* recv_if == NULL on the first node. */
 484                 if (tmp_neigh_node->if_incoming == recv_if)
 485                         continue;
 486
 487                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 488                         continue;
 489
 490                 router = tmp_neigh_node;
 491                 break;
 492         }
 493
 494         /* use the first candidate if nothing was found. */
 495         if (!router && first_candidate &&
 496             atomic_inc_not_zero(&first_candidate->refcount))
 497                 router = first_candidate;
 498
 499         if (!router)
 500                 goto out;
 501
 502         /* selected should point to the next element
 503          * after the current router
 504          */
 505         spin_lock_bh(&primary_orig->neigh_list_lock);
 506         /* this is a list_move(), which unfortunately
 507          * does not exist as rcu version
 508          */
 509         list_del_rcu(&primary_orig->bond_list);
 510         list_add_rcu(&primary_orig->bond_list,
 511                      &router->bonding_list);
 512         spin_unlock_bh(&primary_orig->neigh_list_lock);
 513
 514 out:
 515         rcu_read_unlock();
 516         return router;
 517 }
 518
 519 /**
 520  * batadv_find_ifalter_router - find the best of the remaining candidates which
 521  *  are not using this interface
 522  * @bat_priv: the bat priv with all the soft interface information
 523  * @primary_orig: the destination
 524  * @recv_if: the interface that the router returned by this function has to not
 525  *  use
 526  *
 527  * Returns the best candidate towards primary_orig that is not using recv_if.
 528  * Increases the returned neighbor's refcount
 529  */
 530 static struct batadv_neigh_node *
 531 batadv_find_ifalter_router(struct batadv_priv *bat_priv,
 532                            struct batadv_orig_node *primary_orig,
 533                            const struct batadv_hard_iface *recv_if)
 534 {
 535         struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
 536         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 537         struct batadv_neigh_node *tmp_neigh_node;
 538
 539         rcu_read_lock();
 540         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 541                                 bonding_list) {
 542                 if (!first_candidate)
 543                         first_candidate = tmp_neigh_node;
 544
 545                 /* recv_if == NULL on the first node. */
 546                 if (tmp_neigh_node->if_incoming == recv_if)
 547                         continue;
 548
 549                 if (router && bao->bat_neigh_cmp(tmp_neigh_node, router))
 550                         continue;
 551
 552                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 553                         continue;
 554
 555                 /* decrement refcount of previously selected router */
 556                 if (router)
 557                         batadv_neigh_node_free_ref(router);
 558
 559                 /* we found a better router (or at least one valid router) */
 560                 router = tmp_neigh_node;
 561         }
 562
 563         /* use the first candidate if nothing was found. */
 564         if (!router && first_candidate &&
 565             atomic_inc_not_zero(&first_candidate->refcount))
 566                 router = first_candidate;
 567
 568         rcu_read_unlock();
 569         return router;
 570 }
 571
 572 /**
 573  * batadv_check_unicast_packet - Check for malformed unicast packets
 574  * @bat_priv: the bat priv with all the soft interface information
 575  * @skb: packet to check
 576  * @hdr_size: size of header to pull
 577  *
 578  * Check for short header and bad addresses in given packet. Returns negative
 579  * value when check fails and 0 otherwise. The negative value depends on the
 580  * reason: -ENODATA for bad header, -EBADR for broadcast destination or source,
 581  * and -EREMOTE for non-local (other host) destination.
 582  */
 583 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 584                                        struct sk_buff *skb, int hdr_size)
 585 {
 586         struct ethhdr *ethhdr;
 587
 588         /* drop packet if it has not necessary minimum size */
 589         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 590                 return -ENODATA;
 591
 592         ethhdr = eth_hdr(skb);
 593
 594         /* packet with unicast indication but broadcast recipient */
 595         if (is_broadcast_ether_addr(ethhdr->h_dest))
 596                 return -EBADR;
 597
 598         /* packet with broadcast sender address */
 599         if (is_broadcast_ether_addr(ethhdr->h_source))
 600                 return -EBADR;
 601
 602         /* not for me */
 603         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 604                 return -EREMOTE;
 605
 606         return 0;
 607 }
 608
 609 /* find a suitable router for this originator, and use
 610  * bonding if possible. increases the found neighbors
 611  * refcount.
 612  */
 613 struct batadv_neigh_node *
 614 batadv_find_router(struct batadv_priv *bat_priv,
 615                    struct batadv_orig_node *orig_node,
 616                    const struct batadv_hard_iface *recv_if)
 617 {
 618         struct batadv_orig_node *primary_orig_node;
 619         struct batadv_orig_node *router_orig;
 620         struct batadv_neigh_node *router;
 621         static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
 622         int bonding_enabled;
 623         uint8_t *primary_addr;
 624
 625         if (!orig_node)
 626                 return NULL;
 627
 628         router = batadv_orig_node_get_router(orig_node);
 629         if (!router)
 630                 goto err;
 631
 632         /* without bonding, the first node should
 633          * always choose the default router.
 634          */
 635         bonding_enabled = atomic_read(&bat_priv->bonding);
 636
 637         rcu_read_lock();
 638         /* select default router to output */
 639         router_orig = router->orig_node;
 640         if (!router_orig)
 641                 goto err_unlock;
 642
 643         if ((!recv_if) && (!bonding_enabled))
 644                 goto return_router;
 645
 646         primary_addr = router_orig->primary_addr;
 647
 648         /* if we have something in the primary_addr, we can search
 649          * for a potential bonding candidate.
 650          */
 651         if (batadv_compare_eth(primary_addr, zero_mac))
 652                 goto return_router;
 653
 654         /* find the orig_node which has the primary interface. might
 655          * even be the same as our router_orig in many cases
 656          */
 657         if (batadv_compare_eth(primary_addr, router_orig->orig)) {
 658                 primary_orig_node = router_orig;
 659         } else {
 660                 primary_orig_node = batadv_orig_hash_find(bat_priv,
 661                                                           primary_addr);
 662                 if (!primary_orig_node)
 663                         goto return_router;
 664
 665                 batadv_orig_node_free_ref(primary_orig_node);
 666         }
 667
 668         /* with less than 2 candidates, we can't do any
 669          * bonding and prefer the original router.
 670          */
 671         if (atomic_read(&primary_orig_node->bond_candidates) < 2)
 672                 goto return_router;
 673
 674         /* all nodes between should choose a candidate which
 675          * is is not on the interface where the packet came
 676          * in.
 677          */
 678         batadv_neigh_node_free_ref(router);
 679
 680         if (bonding_enabled)
 681                 router = batadv_find_bond_router(primary_orig_node, recv_if);
 682         else
 683                 router = batadv_find_ifalter_router(bat_priv, primary_orig_node,
 684                                                     recv_if);
 685
 686 return_router:
 687         if (router && router->if_incoming->if_status != BATADV_IF_ACTIVE)
 688                 goto err_unlock;
 689
 690         rcu_read_unlock();
 691         return router;
 692 err_unlock:
 693         rcu_read_unlock();
 694 err:
 695         if (router)
 696                 batadv_neigh_node_free_ref(router);
 697         return NULL;
 698 }
 699
 700 static int batadv_route_unicast_packet(struct sk_buff *skb,
 701                                        struct batadv_hard_iface *recv_if)
 702 {
 703         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 704         struct batadv_orig_node *orig_node = NULL;
 705         struct batadv_unicast_packet *unicast_packet;
 706         struct ethhdr *ethhdr = eth_hdr(skb);
 707         int res, hdr_len, ret = NET_RX_DROP;
 708
 709         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 710
 711         /* TTL exceeded */
 712         if (unicast_packet->header.ttl < 2) {
 713                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 714                          ethhdr->h_source, unicast_packet->dest);
 715                 goto out;
 716         }
 717
 718         /* get routing information */
 719         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 720
 721         if (!orig_node)
 722                 goto out;
 723
 724         /* create a copy of the skb, if needed, to modify it. */
 725         if (skb_cow(skb, ETH_HLEN) < 0)
 726                 goto out;
 727
 728         /* decrement ttl */
 729         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 730         unicast_packet->header.ttl--;
 731
 732         switch (unicast_packet->header.packet_type) {
 733         case BATADV_UNICAST_4ADDR:
 734                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 735                 break;
 736         case BATADV_UNICAST:
 737                 hdr_len = sizeof(struct batadv_unicast_packet);
 738                 break;
 739         default:
 740                 /* other packet types not supported - yet */
 741                 hdr_len = -1;
 742                 break;
 743         }
 744
 745         if (hdr_len > 0)
 746                 batadv_skb_set_priority(skb, hdr_len);
 747
 748         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 749
 750         /* translate transmit result into receive result */
 751         if (res == NET_XMIT_SUCCESS) {
 752                 /* skb was transmitted and consumed */
 753                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 754                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 755                                    skb->len + ETH_HLEN);
 756
 757                 ret = NET_RX_SUCCESS;
 758         } else if (res == NET_XMIT_POLICED) {
 759                 /* skb was buffered and consumed */
 760                 ret = NET_RX_SUCCESS;
 761         }
 762
 763 out:
 764         if (orig_node)
 765                 batadv_orig_node_free_ref(orig_node);
 766         return ret;
 767 }
 768
 769 /**
 770  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 771  * @bat_priv: the bat priv with all the soft interface information
 772  * @unicast_packet: the unicast header to be updated
 773  * @dst_addr: the payload destination
 774  * @vid: VLAN identifier
 775  *
 776  * Search the translation table for dst_addr and update the unicast header with
 777  * the new corresponding information (originator address where the destination
 778  * client currently is and its known TTVN)
 779  *
 780  * Returns true if the packet header has been updated, false otherwise
 781  */
 782 static bool
 783 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 784                               struct batadv_unicast_packet *unicast_packet,
 785                               uint8_t *dst_addr, unsigned short vid)
 786 {
 787         struct batadv_orig_node *orig_node = NULL;
 788         struct batadv_hard_iface *primary_if = NULL;
 789         bool ret = false;
 790         uint8_t *orig_addr, orig_ttvn;
 791
 792         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 793                 primary_if = batadv_primary_if_get_selected(bat_priv);
 794                 if (!primary_if)
 795                         goto out;
 796                 orig_addr = primary_if->net_dev->dev_addr;
 797                 orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 798         } else {
 799                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 800                                                      vid);
 801                 if (!orig_node)
 802                         goto out;
 803
 804                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 805                         goto out;
 806
 807                 orig_addr = orig_node->orig;
 808                 orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 809         }
 810
 811         /* update the packet header */
 812         memcpy(unicast_packet->dest, orig_addr, ETH_ALEN);
 813         unicast_packet->ttvn = orig_ttvn;
 814
 815         ret = true;
 816 out:
 817         if (primary_if)
 818                 batadv_hardif_free_ref(primary_if);
 819         if (orig_node)
 820                 batadv_orig_node_free_ref(orig_node);
 821
 822         return ret;
 823 }
 824
 825 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 826                                      struct sk_buff *skb, int hdr_len) {
 827         struct batadv_unicast_packet *unicast_packet;
 828         struct batadv_hard_iface *primary_if;
 829         struct batadv_orig_node *orig_node;
 830         uint8_t curr_ttvn, old_ttvn;
 831         struct ethhdr *ethhdr;
 832         unsigned short vid;
 833         int is_old_ttvn;
 834
 835         /* check if there is enough data before accessing it */
 836         if (pskb_may_pull(skb, hdr_len + ETH_HLEN) < 0)
 837                 return 0;
 838
 839         /* create a copy of the skb (in case of for re-routing) to modify it. */
 840         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 841                 return 0;
 842
 843         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 844         vid = batadv_get_vid(skb, hdr_len);
 845         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 846
 847         /* check if the destination client was served by this node and it is now
 848          * roaming. In this case, it means that the node has got a ROAM_ADV
 849          * message and that it knows the new destination in the mesh to re-route
 850          * the packet to
 851          */
 852         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 853                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 854                                                   ethhdr->h_dest, vid))
 855                         net_ratelimited_function(batadv_dbg, BATADV_DBG_TT,
 856                                                  bat_priv,
 857                                                  "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 858                                                  unicast_packet->dest,
 859                                                  ethhdr->h_dest);
 860                 /* at this point the mesh destination should have been
 861                  * substituted with the originator address found in the global
 862                  * table. If not, let the packet go untouched anyway because
 863                  * there is nothing the node can do
 864                  */
 865                 return 1;
 866         }
 867
 868         /* retrieve the TTVN known by this node for the packet destination. This
 869          * value is used later to check if the node which sent (or re-routed
 870          * last time) the packet had an updated information or not
 871          */
 872         curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 873         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 874                 orig_node = batadv_orig_hash_find(bat_priv,
 875                                                   unicast_packet->dest);
 876                 /* if it is not possible to find the orig_node representing the
 877                  * destination, the packet can immediately be dropped as it will
 878                  * not be possible to deliver it
 879                  */
 880                 if (!orig_node)
 881                         return 0;
 882
 883                 curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 884                 batadv_orig_node_free_ref(orig_node);
 885         }
 886
 887         /* check if the TTVN contained in the packet is fresher than what the
 888          * node knows
 889          */
 890         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 891         if (!is_old_ttvn)
 892                 return 1;
 893
 894         old_ttvn = unicast_packet->ttvn;
 895         /* the packet was forged based on outdated network information. Its
 896          * destination can possibly be updated and forwarded towards the new
 897          * target host
 898          */
 899         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 900                                           ethhdr->h_dest, vid)) {
 901                 net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv,
 902                                          "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 903                                          unicast_packet->dest, ethhdr->h_dest,
 904                                          old_ttvn, curr_ttvn);
 905                 return 1;
 906         }
 907
 908         /* the packet has not been re-routed: either the destination is
 909          * currently served by this node or there is no destination at all and
 910          * it is possible to drop the packet
 911          */
 912         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 913                 return 0;
 914
 915         /* update the header in order to let the packet be delivered to this
 916          * node's soft interface
 917          */
 918         primary_if = batadv_primary_if_get_selected(bat_priv);
 919         if (!primary_if)
 920                 return 0;
 921
 922         memcpy(unicast_packet->dest, primary_if->net_dev->dev_addr, ETH_ALEN);
 923
 924         batadv_hardif_free_ref(primary_if);
 925
 926         unicast_packet->ttvn = curr_ttvn;
 927
 928         return 1;
 929 }
 930
 931 /**
 932  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 933  *      are in the unicast number space but not yet known to the implementation
 934  * @skb: unicast tvlv packet to process
 935  * @recv_if: pointer to interface this packet was received on
 936  *
 937  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 938  * otherwise.
 939  */
 940 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 941                                          struct batadv_hard_iface *recv_if)
 942 {
 943         struct batadv_unicast_packet *unicast_packet;
 944         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 945         int check, hdr_size = sizeof(*unicast_packet);
 946
 947         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 948         if (check < 0)
 949                 return NET_RX_DROP;
 950
 951         /* we don't know about this type, drop it. */
 952         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 953         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 954                 return NET_RX_DROP;
 955
 956         return batadv_route_unicast_packet(skb, recv_if);
 957 }
 958
 959 int batadv_recv_unicast_packet(struct sk_buff *skb,
 960                                struct batadv_hard_iface *recv_if)
 961 {
 962         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 963         struct batadv_unicast_packet *unicast_packet;
 964         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 965         uint8_t *orig_addr;
 966         struct batadv_orig_node *orig_node = NULL;
 967         int check, hdr_size = sizeof(*unicast_packet);
 968         bool is4addr;
 969
 970         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 971         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 972
 973         is4addr = unicast_packet->header.packet_type == BATADV_UNICAST_4ADDR;
 974         /* the caller function should have already pulled 2 bytes */
 975         if (is4addr)
 976                 hdr_size = sizeof(*unicast_4addr_packet);
 977
 978         /* function returns -EREMOTE for promiscuous packets */
 979         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 980
 981         /* Even though the packet is not for us, we might save it to use for
 982          * decoding a later received coded packet
 983          */
 984         if (check == -EREMOTE)
 985                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 986
 987         if (check < 0)
 988                 return NET_RX_DROP;
 989         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 990                 return NET_RX_DROP;
 991
 992         /* packet for me */
 993         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 994                 if (is4addr) {
 995                         batadv_dat_inc_counter(bat_priv,
 996                                                unicast_4addr_packet->subtype);
 997                         orig_addr = unicast_4addr_packet->src;
 998                         orig_node = batadv_orig_hash_find(bat_priv, orig_addr);
 999                 }
1000
1001                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
1002                                                           hdr_size))
1003                         goto rx_success;
1004                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
1005                                                         hdr_size))
1006                         goto rx_success;
1007
1008                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1009                                     orig_node);
1010
1011 rx_success:
1012                 if (orig_node)
1013                         batadv_orig_node_free_ref(orig_node);
1014
1015                 return NET_RX_SUCCESS;
1016         }
1017
1018         return batadv_route_unicast_packet(skb, recv_if);
1019 }
1020
1021 /**
1022  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
1023  * @skb: unicast tvlv packet to process
1024  * @recv_if: pointer to interface this packet was received on
1025  * @dst_addr: the payload destination
1026  *
1027  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1028  * otherwise.
1029  */
1030 int batadv_recv_unicast_tvlv(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_unicast_tvlv_packet *unicast_tvlv_packet;
1035         unsigned char *tvlv_buff;
1036         uint16_t tvlv_buff_len;
1037         int hdr_size = sizeof(*unicast_tvlv_packet);
1038         int ret = NET_RX_DROP;
1039
1040         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
1041                 return NET_RX_DROP;
1042
1043         /* the header is likely to be modified while forwarding */
1044         if (skb_cow(skb, hdr_size) < 0)
1045                 return NET_RX_DROP;
1046
1047         /* packet needs to be linearized to access the tvlv content */
1048         if (skb_linearize(skb) < 0)
1049                 return NET_RX_DROP;
1050
1051         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
1052
1053         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1054         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
1055
1056         if (tvlv_buff_len > skb->len - hdr_size)
1057                 return NET_RX_DROP;
1058
1059         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
1060                                              unicast_tvlv_packet->src,
1061                                              unicast_tvlv_packet->dst,
1062                                              tvlv_buff, tvlv_buff_len);
1063
1064         if (ret != NET_RX_SUCCESS)
1065                 ret = batadv_route_unicast_packet(skb, recv_if);
1066
1067         return ret;
1068 }
1069
1070 /**
1071  * batadv_recv_frag_packet - process received fragment
1072  * @skb: the received fragment
1073  * @recv_if: interface that the skb is received on
1074  *
1075  * This function does one of the three following things: 1) Forward fragment, if
1076  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
1077  * lack further fragments; 3) Merge fragments, if we have all needed parts.
1078  *
1079  * Return NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1080  */
1081 int batadv_recv_frag_packet(struct sk_buff *skb,
1082                             struct batadv_hard_iface *recv_if)
1083 {
1084         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1085         struct batadv_orig_node *orig_node_src = NULL;
1086         struct batadv_frag_packet *frag_packet;
1087         int ret = NET_RX_DROP;
1088
1089         if (batadv_check_unicast_packet(bat_priv, skb,
1090                                         sizeof(*frag_packet)) < 0)
1091                 goto out;
1092
1093         frag_packet = (struct batadv_frag_packet *)skb->data;
1094         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1095         if (!orig_node_src)
1096                 goto out;
1097
1098         /* Route the fragment if it is not for us and too big to be merged. */
1099         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1100             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1101                 ret = NET_RX_SUCCESS;
1102                 goto out;
1103         }
1104
1105         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1106         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1107
1108         /* Add fragment to buffer and merge if possible. */
1109         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1110                 goto out;
1111
1112         /* Deliver merged packet to the appropriate handler, if it was
1113          * merged
1114          */
1115         if (skb)
1116                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1117                                        &recv_if->batman_adv_ptype, NULL);
1118
1119         ret = NET_RX_SUCCESS;
1120
1121 out:
1122         if (orig_node_src)
1123                 batadv_orig_node_free_ref(orig_node_src);
1124
1125         return ret;
1126 }
1127
1128 int batadv_recv_bcast_packet(struct sk_buff *skb,
1129                              struct batadv_hard_iface *recv_if)
1130 {
1131         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1132         struct batadv_orig_node *orig_node = NULL;
1133         struct batadv_bcast_packet *bcast_packet;
1134         struct ethhdr *ethhdr;
1135         int hdr_size = sizeof(*bcast_packet);
1136         int ret = NET_RX_DROP;
1137         int32_t seq_diff;
1138
1139         /* drop packet if it has not necessary minimum size */
1140         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1141                 goto out;
1142
1143         ethhdr = eth_hdr(skb);
1144
1145         /* packet with broadcast indication but unicast recipient */
1146         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1147                 goto out;
1148
1149         /* packet with broadcast sender address */
1150         if (is_broadcast_ether_addr(ethhdr->h_source))
1151                 goto out;
1152
1153         /* ignore broadcasts sent by myself */
1154         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1155                 goto out;
1156
1157         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1158
1159         /* ignore broadcasts originated by myself */
1160         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1161                 goto out;
1162
1163         if (bcast_packet->header.ttl < 2)
1164                 goto out;
1165
1166         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1167
1168         if (!orig_node)
1169                 goto out;
1170
1171         spin_lock_bh(&orig_node->bcast_seqno_lock);
1172
1173         /* check whether the packet is a duplicate */
1174         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1175                             ntohl(bcast_packet->seqno)))
1176                 goto spin_unlock;
1177
1178         seq_diff = ntohl(bcast_packet->seqno) - orig_node->last_bcast_seqno;
1179
1180         /* check whether the packet is old and the host just restarted. */
1181         if (batadv_window_protected(bat_priv, seq_diff,
1182                                     &orig_node->bcast_seqno_reset))
1183                 goto spin_unlock;
1184
1185         /* mark broadcast in flood history, update window position
1186          * if required.
1187          */
1188         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1189                 orig_node->last_bcast_seqno = ntohl(bcast_packet->seqno);
1190
1191         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1192
1193         /* check whether this has been sent by another originator before */
1194         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1195                 goto out;
1196
1197         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1198
1199         /* rebroadcast packet */
1200         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1201
1202         /* don't hand the broadcast up if it is from an originator
1203          * from the same backbone.
1204          */
1205         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1206                 goto out;
1207
1208         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1209                 goto rx_success;
1210         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1211                 goto rx_success;
1212
1213         /* broadcast for me */
1214         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1215                             orig_node);
1216
1217 rx_success:
1218         ret = NET_RX_SUCCESS;
1219         goto out;
1220
1221 spin_unlock:
1222         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1223 out:
1224         if (orig_node)
1225                 batadv_orig_node_free_ref(orig_node);
1226         return ret;
1227 }