linux/net/batman-adv/routing.c
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   1/* Copyright (C) 2007-2012 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 "vis.h"
  29#include "unicast.h"
  30#include "bridge_loop_avoidance.h"
  31
  32static int batadv_route_unicast_packet(struct sk_buff *skb,
  33                                       struct batadv_hard_iface *recv_if);
  34
  35void batadv_slide_own_bcast_window(struct batadv_hard_iface *hard_iface)
  36{
  37        struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
  38        struct batadv_hashtable *hash = bat_priv->orig_hash;
  39        struct hlist_node *node;
  40        struct hlist_head *head;
  41        struct batadv_orig_node *orig_node;
  42        unsigned long *word;
  43        uint32_t i;
  44        size_t word_index;
  45        uint8_t *w;
  46
  47        for (i = 0; i < hash->size; i++) {
  48                head = &hash->table[i];
  49
  50                rcu_read_lock();
  51                hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
  52                        spin_lock_bh(&orig_node->ogm_cnt_lock);
  53                        word_index = hard_iface->if_num * BATADV_NUM_WORDS;
  54                        word = &(orig_node->bcast_own[word_index]);
  55
  56                        batadv_bit_get_packet(bat_priv, word, 1, 0);
  57                        w = &orig_node->bcast_own_sum[hard_iface->if_num];
  58                        *w = bitmap_weight(word, BATADV_TQ_LOCAL_WINDOW_SIZE);
  59                        spin_unlock_bh(&orig_node->ogm_cnt_lock);
  60                }
  61                rcu_read_unlock();
  62        }
  63}
  64
  65static void _batadv_update_route(struct batadv_priv *bat_priv,
  66                                 struct batadv_orig_node *orig_node,
  67                                 struct batadv_neigh_node *neigh_node)
  68{
  69        struct batadv_neigh_node *curr_router;
  70
  71        curr_router = batadv_orig_node_get_router(orig_node);
  72
  73        /* route deleted */
  74        if ((curr_router) && (!neigh_node)) {
  75                batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  76                           "Deleting route towards: %pM\n", orig_node->orig);
  77                batadv_tt_global_del_orig(bat_priv, orig_node,
  78                                          "Deleted route towards originator");
  79
  80        /* route added */
  81        } else if ((!curr_router) && (neigh_node)) {
  82
  83                batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  84                           "Adding route towards: %pM (via %pM)\n",
  85                           orig_node->orig, neigh_node->addr);
  86        /* route changed */
  87        } else if (neigh_node && curr_router) {
  88                batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  89                           "Changing route towards: %pM (now via %pM - was via %pM)\n",
  90                           orig_node->orig, neigh_node->addr,
  91                           curr_router->addr);
  92        }
  93
  94        if (curr_router)
  95                batadv_neigh_node_free_ref(curr_router);
  96
  97        /* increase refcount of new best neighbor */
  98        if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
  99                neigh_node = NULL;
 100
 101        spin_lock_bh(&orig_node->neigh_list_lock);
 102        rcu_assign_pointer(orig_node->router, neigh_node);
 103        spin_unlock_bh(&orig_node->neigh_list_lock);
 104
 105        /* decrease refcount of previous best neighbor */
 106        if (curr_router)
 107                batadv_neigh_node_free_ref(curr_router);
 108}
 109
 110void batadv_update_route(struct batadv_priv *bat_priv,
 111                         struct batadv_orig_node *orig_node,
 112                         struct batadv_neigh_node *neigh_node)
 113{
 114        struct batadv_neigh_node *router = NULL;
 115
 116        if (!orig_node)
 117                goto out;
 118
 119        router = batadv_orig_node_get_router(orig_node);
 120
 121        if (router != neigh_node)
 122                _batadv_update_route(bat_priv, orig_node, neigh_node);
 123
 124out:
 125        if (router)
 126                batadv_neigh_node_free_ref(router);
 127}
 128
 129/* caller must hold the neigh_list_lock */
 130void batadv_bonding_candidate_del(struct batadv_orig_node *orig_node,
 131                                  struct batadv_neigh_node *neigh_node)
 132{
 133        /* this neighbor is not part of our candidate list */
 134        if (list_empty(&neigh_node->bonding_list))
 135                goto out;
 136
 137        list_del_rcu(&neigh_node->bonding_list);
 138        INIT_LIST_HEAD(&neigh_node->bonding_list);
 139        batadv_neigh_node_free_ref(neigh_node);
 140        atomic_dec(&orig_node->bond_candidates);
 141
 142out:
 143        return;
 144}
 145
 146void batadv_bonding_candidate_add(struct batadv_orig_node *orig_node,
 147                                  struct batadv_neigh_node *neigh_node)
 148{
 149        struct hlist_node *node;
 150        struct batadv_neigh_node *tmp_neigh_node, *router = NULL;
 151        uint8_t interference_candidate = 0;
 152
 153        spin_lock_bh(&orig_node->neigh_list_lock);
 154
 155        /* only consider if it has the same primary address ...  */
 156        if (!batadv_compare_eth(orig_node->orig,
 157                                neigh_node->orig_node->primary_addr))
 158                goto candidate_del;
 159
 160        router = batadv_orig_node_get_router(orig_node);
 161        if (!router)
 162                goto candidate_del;
 163
 164        /* ... and is good enough to be considered */
 165        if (neigh_node->tq_avg < router->tq_avg - BATADV_BONDING_TQ_THRESHOLD)
 166                goto candidate_del;
 167
 168        /* check if we have another candidate with the same mac address or
 169         * interface. If we do, we won't select this candidate because of
 170         * possible interference.
 171         */
 172        hlist_for_each_entry_rcu(tmp_neigh_node, node,
 173                                 &orig_node->neigh_list, list) {
 174
 175                if (tmp_neigh_node == neigh_node)
 176                        continue;
 177
 178                /* we only care if the other candidate is even
 179                 * considered as candidate.
 180                 */
 181                if (list_empty(&tmp_neigh_node->bonding_list))
 182                        continue;
 183
 184                if ((neigh_node->if_incoming == tmp_neigh_node->if_incoming) ||
 185                    (batadv_compare_eth(neigh_node->addr,
 186                                        tmp_neigh_node->addr))) {
 187                        interference_candidate = 1;
 188                        break;
 189                }
 190        }
 191
 192        /* don't care further if it is an interference candidate */
 193        if (interference_candidate)
 194                goto candidate_del;
 195
 196        /* this neighbor already is part of our candidate list */
 197        if (!list_empty(&neigh_node->bonding_list))
 198                goto out;
 199
 200        if (!atomic_inc_not_zero(&neigh_node->refcount))
 201                goto out;
 202
 203        list_add_rcu(&neigh_node->bonding_list, &orig_node->bond_list);
 204        atomic_inc(&orig_node->bond_candidates);
 205        goto out;
 206
 207candidate_del:
 208        batadv_bonding_candidate_del(orig_node, neigh_node);
 209
 210out:
 211        spin_unlock_bh(&orig_node->neigh_list_lock);
 212
 213        if (router)
 214                batadv_neigh_node_free_ref(router);
 215}
 216
 217/* copy primary address for bonding */
 218void
 219batadv_bonding_save_primary(const struct batadv_orig_node *orig_node,
 220                            struct batadv_orig_node *orig_neigh_node,
 221                            const struct batadv_ogm_packet *batman_ogm_packet)
 222{
 223        if (!(batman_ogm_packet->flags & BATADV_PRIMARIES_FIRST_HOP))
 224                return;
 225
 226        memcpy(orig_neigh_node->primary_addr, orig_node->orig, ETH_ALEN);
 227}
 228
 229/* checks whether the host restarted and is in the protection time.
 230 * returns:
 231 *  0 if the packet is to be accepted
 232 *  1 if the packet is to be ignored.
 233 */
 234int batadv_window_protected(struct batadv_priv *bat_priv, int32_t seq_num_diff,
 235                            unsigned long *last_reset)
 236{
 237        if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
 238            seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 239                if (!batadv_has_timed_out(*last_reset,
 240                                          BATADV_RESET_PROTECTION_MS))
 241                        return 1;
 242
 243                *last_reset = jiffies;
 244                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 245                           "old packet received, start protection\n");
 246        }
 247
 248        return 0;
 249}
 250
 251bool batadv_check_management_packet(struct sk_buff *skb,
 252                                    struct batadv_hard_iface *hard_iface,
 253                                    int header_len)
 254{
 255        struct ethhdr *ethhdr;
 256
 257        /* drop packet if it has not necessary minimum size */
 258        if (unlikely(!pskb_may_pull(skb, header_len)))
 259                return false;
 260
 261        ethhdr = (struct ethhdr *)skb_mac_header(skb);
 262
 263        /* packet with broadcast indication but unicast recipient */
 264        if (!is_broadcast_ether_addr(ethhdr->h_dest))
 265                return false;
 266
 267        /* packet with broadcast sender address */
 268        if (is_broadcast_ether_addr(ethhdr->h_source))
 269                return false;
 270
 271        /* create a copy of the skb, if needed, to modify it. */
 272        if (skb_cow(skb, 0) < 0)
 273                return false;
 274
 275        /* keep skb linear */
 276        if (skb_linearize(skb) < 0)
 277                return false;
 278
 279        return true;
 280}
 281
 282static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 283                                      struct sk_buff *skb, size_t icmp_len)
 284{
 285        struct batadv_hard_iface *primary_if = NULL;
 286        struct batadv_orig_node *orig_node = NULL;
 287        struct batadv_neigh_node *router = NULL;
 288        struct batadv_icmp_packet_rr *icmp_packet;
 289        int ret = NET_RX_DROP;
 290
 291        icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 292
 293        /* add data to device queue */
 294        if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 295                batadv_socket_receive_packet(icmp_packet, icmp_len);
 296                goto out;
 297        }
 298
 299        primary_if = batadv_primary_if_get_selected(bat_priv);
 300        if (!primary_if)
 301                goto out;
 302
 303        /* answer echo request (ping) */
 304        /* get routing information */
 305        orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 306        if (!orig_node)
 307                goto out;
 308
 309        router = batadv_orig_node_get_router(orig_node);
 310        if (!router)
 311                goto out;
 312
 313        /* create a copy of the skb, if needed, to modify it. */
 314        if (skb_cow(skb, ETH_HLEN) < 0)
 315                goto out;
 316
 317        icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 318
 319        memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
 320        memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 321        icmp_packet->msg_type = BATADV_ECHO_REPLY;
 322        icmp_packet->header.ttl = BATADV_TTL;
 323
 324        batadv_send_skb_packet(skb, router->if_incoming, router->addr);
 325        ret = NET_RX_SUCCESS;
 326
 327out:
 328        if (primary_if)
 329                batadv_hardif_free_ref(primary_if);
 330        if (router)
 331                batadv_neigh_node_free_ref(router);
 332        if (orig_node)
 333                batadv_orig_node_free_ref(orig_node);
 334        return ret;
 335}
 336
 337static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 338                                         struct sk_buff *skb)
 339{
 340        struct batadv_hard_iface *primary_if = NULL;
 341        struct batadv_orig_node *orig_node = NULL;
 342        struct batadv_neigh_node *router = NULL;
 343        struct batadv_icmp_packet *icmp_packet;
 344        int ret = NET_RX_DROP;
 345
 346        icmp_packet = (struct batadv_icmp_packet *)skb->data;
 347
 348        /* send TTL exceeded if packet is an echo request (traceroute) */
 349        if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 350                pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 351                         icmp_packet->orig, icmp_packet->dst);
 352                goto out;
 353        }
 354
 355        primary_if = batadv_primary_if_get_selected(bat_priv);
 356        if (!primary_if)
 357                goto out;
 358
 359        /* get routing information */
 360        orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 361        if (!orig_node)
 362                goto out;
 363
 364        router = batadv_orig_node_get_router(orig_node);
 365        if (!router)
 366                goto out;
 367
 368        /* create a copy of the skb, if needed, to modify it. */
 369        if (skb_cow(skb, ETH_HLEN) < 0)
 370                goto out;
 371
 372        icmp_packet = (struct batadv_icmp_packet *)skb->data;
 373
 374        memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
 375        memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 376        icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 377        icmp_packet->header.ttl = BATADV_TTL;
 378
 379        batadv_send_skb_packet(skb, router->if_incoming, router->addr);
 380        ret = NET_RX_SUCCESS;
 381
 382out:
 383        if (primary_if)
 384                batadv_hardif_free_ref(primary_if);
 385        if (router)
 386                batadv_neigh_node_free_ref(router);
 387        if (orig_node)
 388                batadv_orig_node_free_ref(orig_node);
 389        return ret;
 390}
 391
 392
 393int batadv_recv_icmp_packet(struct sk_buff *skb,
 394                            struct batadv_hard_iface *recv_if)
 395{
 396        struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 397        struct batadv_icmp_packet_rr *icmp_packet;
 398        struct ethhdr *ethhdr;
 399        struct batadv_orig_node *orig_node = NULL;
 400        struct batadv_neigh_node *router = NULL;
 401        int hdr_size = sizeof(struct batadv_icmp_packet);
 402        int ret = NET_RX_DROP;
 403
 404        /* we truncate all incoming icmp packets if they don't match our size */
 405        if (skb->len >= sizeof(struct batadv_icmp_packet_rr))
 406                hdr_size = sizeof(struct batadv_icmp_packet_rr);
 407
 408        /* drop packet if it has not necessary minimum size */
 409        if (unlikely(!pskb_may_pull(skb, hdr_size)))
 410                goto out;
 411
 412        ethhdr = (struct ethhdr *)skb_mac_header(skb);
 413
 414        /* packet with unicast indication but broadcast recipient */
 415        if (is_broadcast_ether_addr(ethhdr->h_dest))
 416                goto out;
 417
 418        /* packet with broadcast sender address */
 419        if (is_broadcast_ether_addr(ethhdr->h_source))
 420                goto out;
 421
 422        /* not for me */
 423        if (!batadv_is_my_mac(ethhdr->h_dest))
 424                goto out;
 425
 426        icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 427
 428        /* add record route information if not full */
 429        if ((hdr_size == sizeof(struct batadv_icmp_packet_rr)) &&
 430            (icmp_packet->rr_cur < BATADV_RR_LEN)) {
 431                memcpy(&(icmp_packet->rr[icmp_packet->rr_cur]),
 432                       ethhdr->h_dest, ETH_ALEN);
 433                icmp_packet->rr_cur++;
 434        }
 435
 436        /* packet for me */
 437        if (batadv_is_my_mac(icmp_packet->dst))
 438                return batadv_recv_my_icmp_packet(bat_priv, skb, hdr_size);
 439
 440        /* TTL exceeded */
 441        if (icmp_packet->header.ttl < 2)
 442                return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 443
 444        /* get routing information */
 445        orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->dst);
 446        if (!orig_node)
 447                goto out;
 448
 449        router = batadv_orig_node_get_router(orig_node);
 450        if (!router)
 451                goto out;
 452
 453        /* create a copy of the skb, if needed, to modify it. */
 454        if (skb_cow(skb, ETH_HLEN) < 0)
 455                goto out;
 456
 457        icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
 458
 459        /* decrement ttl */
 460        icmp_packet->header.ttl--;
 461
 462        /* route it */
 463        batadv_send_skb_packet(skb, router->if_incoming, router->addr);
 464        ret = NET_RX_SUCCESS;
 465
 466out:
 467        if (router)
 468                batadv_neigh_node_free_ref(router);
 469        if (orig_node)
 470                batadv_orig_node_free_ref(orig_node);
 471        return ret;
 472}
 473
 474/* In the bonding case, send the packets in a round
 475 * robin fashion over the remaining interfaces.
 476 *
 477 * This method rotates the bonding list and increases the
 478 * returned router's refcount.
 479 */
 480static struct batadv_neigh_node *
 481batadv_find_bond_router(struct batadv_orig_node *primary_orig,
 482                        const struct batadv_hard_iface *recv_if)
 483{
 484        struct batadv_neigh_node *tmp_neigh_node;
 485        struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
 486
 487        rcu_read_lock();
 488        list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 489                                bonding_list) {
 490                if (!first_candidate)
 491                        first_candidate = tmp_neigh_node;
 492
 493                /* recv_if == NULL on the first node. */
 494                if (tmp_neigh_node->if_incoming == recv_if)
 495                        continue;
 496
 497                if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 498                        continue;
 499
 500                router = tmp_neigh_node;
 501                break;
 502        }
 503
 504        /* use the first candidate if nothing was found. */
 505        if (!router && first_candidate &&
 506            atomic_inc_not_zero(&first_candidate->refcount))
 507                router = first_candidate;
 508
 509        if (!router)
 510                goto out;
 511
 512        /* selected should point to the next element
 513         * after the current router
 514         */
 515        spin_lock_bh(&primary_orig->neigh_list_lock);
 516        /* this is a list_move(), which unfortunately
 517         * does not exist as rcu version
 518         */
 519        list_del_rcu(&primary_orig->bond_list);
 520        list_add_rcu(&primary_orig->bond_list,
 521                     &router->bonding_list);
 522        spin_unlock_bh(&primary_orig->neigh_list_lock);
 523
 524out:
 525        rcu_read_unlock();
 526        return router;
 527}
 528
 529/* Interface Alternating: Use the best of the
 530 * remaining candidates which are not using
 531 * this interface.
 532 *
 533 * Increases the returned router's refcount
 534 */
 535static struct batadv_neigh_node *
 536batadv_find_ifalter_router(struct batadv_orig_node *primary_orig,
 537                           const struct batadv_hard_iface *recv_if)
 538{
 539        struct batadv_neigh_node *tmp_neigh_node;
 540        struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
 541
 542        rcu_read_lock();
 543        list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
 544                                bonding_list) {
 545                if (!first_candidate)
 546                        first_candidate = tmp_neigh_node;
 547
 548                /* recv_if == NULL on the first node. */
 549                if (tmp_neigh_node->if_incoming == recv_if)
 550                        continue;
 551
 552                if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 553                        continue;
 554
 555                /* if we don't have a router yet
 556                 * or this one is better, choose it.
 557                 */
 558                if ((!router) ||
 559                    (tmp_neigh_node->tq_avg > router->tq_avg)) {
 560                        /* decrement refcount of
 561                         * previously selected router
 562                         */
 563                        if (router)
 564                                batadv_neigh_node_free_ref(router);
 565
 566                        router = tmp_neigh_node;
 567                        atomic_inc_not_zero(&router->refcount);
 568                }
 569
 570                batadv_neigh_node_free_ref(tmp_neigh_node);
 571        }
 572
 573        /* use the first candidate if nothing was found. */
 574        if (!router && first_candidate &&
 575            atomic_inc_not_zero(&first_candidate->refcount))
 576                router = first_candidate;
 577
 578        rcu_read_unlock();
 579        return router;
 580}
 581
 582int batadv_recv_tt_query(struct sk_buff *skb, struct batadv_hard_iface *recv_if)
 583{
 584        struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 585        struct batadv_tt_query_packet *tt_query;
 586        uint16_t tt_size;
 587        struct ethhdr *ethhdr;
 588        char tt_flag;
 589        size_t packet_size;
 590
 591        /* drop packet if it has not necessary minimum size */
 592        if (unlikely(!pskb_may_pull(skb,
 593                                    sizeof(struct batadv_tt_query_packet))))
 594                goto out;
 595
 596        /* I could need to modify it */
 597        if (skb_cow(skb, sizeof(struct batadv_tt_query_packet)) < 0)
 598                goto out;
 599
 600        ethhdr = (struct ethhdr *)skb_mac_header(skb);
 601
 602        /* packet with unicast indication but broadcast recipient */
 603        if (is_broadcast_ether_addr(ethhdr->h_dest))
 604                goto out;
 605
 606        /* packet with broadcast sender address */
 607        if (is_broadcast_ether_addr(ethhdr->h_source))
 608                goto out;
 609
 610        tt_query = (struct batadv_tt_query_packet *)skb->data;
 611
 612        switch (tt_query->flags & BATADV_TT_QUERY_TYPE_MASK) {
 613        case BATADV_TT_REQUEST:
 614                batadv_inc_counter(bat_priv, BATADV_CNT_TT_REQUEST_RX);
 615
 616                /* If we cannot provide an answer the tt_request is
 617                 * forwarded
 618                 */
 619                if (!batadv_send_tt_response(bat_priv, tt_query)) {
 620                        if (tt_query->flags & BATADV_TT_FULL_TABLE)
 621                                tt_flag = 'F';
 622                        else
 623                                tt_flag = '.';
 624
 625                        batadv_dbg(BATADV_DBG_TT, bat_priv,
 626                                   "Routing TT_REQUEST to %pM [%c]\n",
 627                                   tt_query->dst,
 628                                   tt_flag);
 629                        return batadv_route_unicast_packet(skb, recv_if);
 630                }
 631                break;
 632        case BATADV_TT_RESPONSE:
 633                batadv_inc_counter(bat_priv, BATADV_CNT_TT_RESPONSE_RX);
 634
 635                if (batadv_is_my_mac(tt_query->dst)) {
 636                        /* packet needs to be linearized to access the TT
 637                         * changes
 638                         */
 639                        if (skb_linearize(skb) < 0)
 640                                goto out;
 641                        /* skb_linearize() possibly changed skb->data */
 642                        tt_query = (struct batadv_tt_query_packet *)skb->data;
 643
 644                        tt_size = batadv_tt_len(ntohs(tt_query->tt_data));
 645
 646                        /* Ensure we have all the claimed data */
 647                        packet_size = sizeof(struct batadv_tt_query_packet);
 648                        packet_size += tt_size;
 649                        if (unlikely(skb_headlen(skb) < packet_size))
 650                                goto out;
 651
 652                        batadv_handle_tt_response(bat_priv, tt_query);
 653                } else {
 654                        if (tt_query->flags & BATADV_TT_FULL_TABLE)
 655                                tt_flag =  'F';
 656                        else
 657                                tt_flag = '.';
 658                        batadv_dbg(BATADV_DBG_TT, bat_priv,
 659                                   "Routing TT_RESPONSE to %pM [%c]\n",
 660                                   tt_query->dst,
 661                                   tt_flag);
 662                        return batadv_route_unicast_packet(skb, recv_if);
 663                }
 664                break;
 665        }
 666
 667out:
 668        /* returning NET_RX_DROP will make the caller function kfree the skb */
 669        return NET_RX_DROP;
 670}
 671
 672int batadv_recv_roam_adv(struct sk_buff *skb, struct batadv_hard_iface *recv_if)
 673{
 674        struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 675        struct batadv_roam_adv_packet *roam_adv_packet;
 676        struct batadv_orig_node *orig_node;
 677        struct ethhdr *ethhdr;
 678
 679        /* drop packet if it has not necessary minimum size */
 680        if (unlikely(!pskb_may_pull(skb,
 681                                    sizeof(struct batadv_roam_adv_packet))))
 682                goto out;
 683
 684        ethhdr = (struct ethhdr *)skb_mac_header(skb);
 685
 686        /* packet with unicast indication but broadcast recipient */
 687        if (is_broadcast_ether_addr(ethhdr->h_dest))
 688                goto out;
 689
 690        /* packet with broadcast sender address */
 691        if (is_broadcast_ether_addr(ethhdr->h_source))
 692                goto out;
 693
 694        batadv_inc_counter(bat_priv, BATADV_CNT_TT_ROAM_ADV_RX);
 695
 696        roam_adv_packet = (struct batadv_roam_adv_packet *)skb->data;
 697
 698        if (!batadv_is_my_mac(roam_adv_packet->dst))
 699                return batadv_route_unicast_packet(skb, recv_if);
 700
 701        /* check if it is a backbone gateway. we don't accept
 702         * roaming advertisement from it, as it has the same
 703         * entries as we have.
 704         */
 705        if (batadv_bla_is_backbone_gw_orig(bat_priv, roam_adv_packet->src))
 706                goto out;
 707
 708        orig_node = batadv_orig_hash_find(bat_priv, roam_adv_packet->src);
 709        if (!orig_node)
 710                goto out;
 711
 712        batadv_dbg(BATADV_DBG_TT, bat_priv,
 713                   "Received ROAMING_ADV from %pM (client %pM)\n",
 714                   roam_adv_packet->src, roam_adv_packet->client);
 715
 716        batadv_tt_global_add(bat_priv, orig_node, roam_adv_packet->client,
 717                             BATADV_TT_CLIENT_ROAM,
 718                             atomic_read(&orig_node->last_ttvn) + 1);
 719
 720        /* Roaming phase starts: I have new information but the ttvn has not
 721         * been incremented yet. This flag will make me check all the incoming
 722         * packets for the correct destination.
 723         */
 724        bat_priv->tt_poss_change = true;
 725
 726        batadv_orig_node_free_ref(orig_node);
 727out:
 728        /* returning NET_RX_DROP will make the caller function kfree the skb */
 729        return NET_RX_DROP;
 730}
 731
 732/* find a suitable router for this originator, and use
 733 * bonding if possible. increases the found neighbors
 734 * refcount.
 735 */
 736struct batadv_neigh_node *
 737batadv_find_router(struct batadv_priv *bat_priv,
 738                   struct batadv_orig_node *orig_node,
 739                   const struct batadv_hard_iface *recv_if)
 740{
 741        struct batadv_orig_node *primary_orig_node;
 742        struct batadv_orig_node *router_orig;
 743        struct batadv_neigh_node *router;
 744        static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
 745        int bonding_enabled;
 746        uint8_t *primary_addr;
 747
 748        if (!orig_node)
 749                return NULL;
 750
 751        router = batadv_orig_node_get_router(orig_node);
 752        if (!router)
 753                goto err;
 754
 755        /* without bonding, the first node should
 756         * always choose the default router.
 757         */
 758        bonding_enabled = atomic_read(&bat_priv->bonding);
 759
 760        rcu_read_lock();
 761        /* select default router to output */
 762        router_orig = router->orig_node;
 763        if (!router_orig)
 764                goto err_unlock;
 765
 766        if ((!recv_if) && (!bonding_enabled))
 767                goto return_router;
 768
 769        primary_addr = router_orig->primary_addr;
 770
 771        /* if we have something in the primary_addr, we can search
 772         * for a potential bonding candidate.
 773         */
 774        if (batadv_compare_eth(primary_addr, zero_mac))
 775                goto return_router;
 776
 777        /* find the orig_node which has the primary interface. might
 778         * even be the same as our router_orig in many cases
 779         */
 780        if (batadv_compare_eth(primary_addr, router_orig->orig)) {
 781                primary_orig_node = router_orig;
 782        } else {
 783                primary_orig_node = batadv_orig_hash_find(bat_priv,
 784                                                          primary_addr);
 785                if (!primary_orig_node)
 786                        goto return_router;
 787
 788                batadv_orig_node_free_ref(primary_orig_node);
 789        }
 790
 791        /* with less than 2 candidates, we can't do any
 792         * bonding and prefer the original router.
 793         */
 794        if (atomic_read(&primary_orig_node->bond_candidates) < 2)
 795                goto return_router;
 796
 797        /* all nodes between should choose a candidate which
 798         * is is not on the interface where the packet came
 799         * in.
 800         */
 801        batadv_neigh_node_free_ref(router);
 802
 803        if (bonding_enabled)
 804                router = batadv_find_bond_router(primary_orig_node, recv_if);
 805        else
 806                router = batadv_find_ifalter_router(primary_orig_node, recv_if);
 807
 808return_router:
 809        if (router && router->if_incoming->if_status != BATADV_IF_ACTIVE)
 810                goto err_unlock;
 811
 812        rcu_read_unlock();
 813        return router;
 814err_unlock:
 815        rcu_read_unlock();
 816err:
 817        if (router)
 818                batadv_neigh_node_free_ref(router);
 819        return NULL;
 820}
 821
 822static int batadv_check_unicast_packet(struct sk_buff *skb, int hdr_size)
 823{
 824        struct ethhdr *ethhdr;
 825
 826        /* drop packet if it has not necessary minimum size */
 827        if (unlikely(!pskb_may_pull(skb, hdr_size)))
 828                return -1;
 829
 830        ethhdr = (struct ethhdr *)skb_mac_header(skb);
 831
 832        /* packet with unicast indication but broadcast recipient */
 833        if (is_broadcast_ether_addr(ethhdr->h_dest))
 834                return -1;
 835
 836        /* packet with broadcast sender address */
 837        if (is_broadcast_ether_addr(ethhdr->h_source))
 838                return -1;
 839
 840        /* not for me */
 841        if (!batadv_is_my_mac(ethhdr->h_dest))
 842                return -1;
 843
 844        return 0;
 845}
 846
 847static int batadv_route_unicast_packet(struct sk_buff *skb,
 848                                       struct batadv_hard_iface *recv_if)
 849{
 850        struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 851        struct batadv_orig_node *orig_node = NULL;
 852        struct batadv_neigh_node *neigh_node = NULL;
 853        struct batadv_unicast_packet *unicast_packet;
 854        struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
 855        int ret = NET_RX_DROP;
 856        struct sk_buff *new_skb;
 857
 858        unicast_packet = (struct batadv_unicast_packet *)skb->data;
 859
 860        /* TTL exceeded */
 861        if (unicast_packet->header.ttl < 2) {
 862                pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 863                         ethhdr->h_source, unicast_packet->dest);
 864                goto out;
 865        }
 866
 867        /* get routing information */
 868        orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 869
 870        if (!orig_node)
 871                goto out;
 872
 873        /* find_router() increases neigh_nodes refcount if found. */
 874        neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
 875
 876        if (!neigh_node)
 877                goto out;
 878
 879        /* create a copy of the skb, if needed, to modify it. */
 880        if (skb_cow(skb, ETH_HLEN) < 0)
 881                goto out;
 882
 883        unicast_packet = (struct batadv_unicast_packet *)skb->data;
 884
 885        if (unicast_packet->header.packet_type == BATADV_UNICAST &&
 886            atomic_read(&bat_priv->fragmentation) &&
 887            skb->len > neigh_node->if_incoming->net_dev->mtu) {
 888                ret = batadv_frag_send_skb(skb, bat_priv,
 889                                           neigh_node->if_incoming,
 890                                           neigh_node->addr);
 891                goto out;
 892        }
 893
 894        if (unicast_packet->header.packet_type == BATADV_UNICAST_FRAG &&
 895            batadv_frag_can_reassemble(skb,
 896                                       neigh_node->if_incoming->net_dev->mtu)) {
 897
 898                ret = batadv_frag_reassemble_skb(skb, bat_priv, &new_skb);
 899
 900                if (ret == NET_RX_DROP)
 901                        goto out;
 902
 903                /* packet was buffered for late merge */
 904                if (!new_skb) {
 905                        ret = NET_RX_SUCCESS;
 906                        goto out;
 907                }
 908
 909                skb = new_skb;
 910                unicast_packet = (struct batadv_unicast_packet *)skb->data;
 911        }
 912
 913        /* decrement ttl */
 914        unicast_packet->header.ttl--;
 915
 916        /* Update stats counter */
 917        batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 918        batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 919                           skb->len + ETH_HLEN);
 920
 921        /* route it */
 922        batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
 923        ret = NET_RX_SUCCESS;
 924
 925out:
 926        if (neigh_node)
 927                batadv_neigh_node_free_ref(neigh_node);
 928        if (orig_node)
 929                batadv_orig_node_free_ref(orig_node);
 930        return ret;
 931}
 932
 933static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 934                                     struct sk_buff *skb) {
 935        uint8_t curr_ttvn;
 936        struct batadv_orig_node *orig_node;
 937        struct ethhdr *ethhdr;
 938        struct batadv_hard_iface *primary_if;
 939        struct batadv_unicast_packet *unicast_packet;
 940        bool tt_poss_change;
 941        int is_old_ttvn;
 942
 943        /* I could need to modify it */
 944        if (skb_cow(skb, sizeof(struct batadv_unicast_packet)) < 0)
 945                return 0;
 946
 947        unicast_packet = (struct batadv_unicast_packet *)skb->data;
 948
 949        if (batadv_is_my_mac(unicast_packet->dest)) {
 950                tt_poss_change = bat_priv->tt_poss_change;
 951                curr_ttvn = (uint8_t)atomic_read(&bat_priv->ttvn);
 952        } else {
 953                orig_node = batadv_orig_hash_find(bat_priv,
 954                                                  unicast_packet->dest);
 955
 956                if (!orig_node)
 957                        return 0;
 958
 959                curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 960                tt_poss_change = orig_node->tt_poss_change;
 961                batadv_orig_node_free_ref(orig_node);
 962        }
 963
 964        /* Check whether I have to reroute the packet */
 965        is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 966        if (is_old_ttvn || tt_poss_change) {
 967                /* check if there is enough data before accessing it */
 968                if (pskb_may_pull(skb, sizeof(struct batadv_unicast_packet) +
 969                                  ETH_HLEN) < 0)
 970                        return 0;
 971
 972                ethhdr = (struct ethhdr *)(skb->data + sizeof(*unicast_packet));
 973
 974                /* we don't have an updated route for this client, so we should
 975                 * not try to reroute the packet!!
 976                 */
 977                if (batadv_tt_global_client_is_roaming(bat_priv,
 978                                                       ethhdr->h_dest))
 979                        return 1;
 980
 981                orig_node = batadv_transtable_search(bat_priv, NULL,
 982                                                     ethhdr->h_dest);
 983
 984                if (!orig_node) {
 985                        if (!batadv_is_my_client(bat_priv, ethhdr->h_dest))
 986                                return 0;
 987                        primary_if = batadv_primary_if_get_selected(bat_priv);
 988                        if (!primary_if)
 989                                return 0;
 990                        memcpy(unicast_packet->dest,
 991                               primary_if->net_dev->dev_addr, ETH_ALEN);
 992                        batadv_hardif_free_ref(primary_if);
 993                } else {
 994                        memcpy(unicast_packet->dest, orig_node->orig,
 995                               ETH_ALEN);
 996                        curr_ttvn = (uint8_t)
 997                                atomic_read(&orig_node->last_ttvn);
 998                        batadv_orig_node_free_ref(orig_node);
 999                }
1000
1001                batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
1002                           "TTVN mismatch (old_ttvn %u new_ttvn %u)! Rerouting unicast packet (for %pM) to %pM\n",
1003                           unicast_packet->ttvn, curr_ttvn, ethhdr->h_dest,
1004                           unicast_packet->dest);
1005
1006                unicast_packet->ttvn = curr_ttvn;
1007        }
1008        return 1;
1009}
1010
1011int batadv_recv_unicast_packet(struct sk_buff *skb,
1012                               struct batadv_hard_iface *recv_if)
1013{
1014        struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1015        struct batadv_unicast_packet *unicast_packet;
1016        int hdr_size = sizeof(*unicast_packet);
1017
1018        if (batadv_check_unicast_packet(skb, hdr_size) < 0)
1019                return NET_RX_DROP;
1020
1021        if (!batadv_check_unicast_ttvn(bat_priv, skb))
1022                return NET_RX_DROP;
1023
1024        unicast_packet = (struct batadv_unicast_packet *)skb->data;
1025
1026        /* packet for me */
1027        if (batadv_is_my_mac(unicast_packet->dest)) {
1028                batadv_interface_rx(recv_if->soft_iface, skb, recv_if,
1029                                    hdr_size);
1030                return NET_RX_SUCCESS;
1031        }
1032
1033        return batadv_route_unicast_packet(skb, recv_if);
1034}
1035
1036int batadv_recv_ucast_frag_packet(struct sk_buff *skb,
1037                                  struct batadv_hard_iface *recv_if)
1038{
1039        struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1040        struct batadv_unicast_frag_packet *unicast_packet;
1041        int hdr_size = sizeof(*unicast_packet);
1042        struct sk_buff *new_skb = NULL;
1043        int ret;
1044
1045        if (batadv_check_unicast_packet(skb, hdr_size) < 0)
1046                return NET_RX_DROP;
1047
1048        if (!batadv_check_unicast_ttvn(bat_priv, skb))
1049                return NET_RX_DROP;
1050
1051        unicast_packet = (struct batadv_unicast_frag_packet *)skb->data;
1052
1053        /* packet for me */
1054        if (batadv_is_my_mac(unicast_packet->dest)) {
1055
1056                ret = batadv_frag_reassemble_skb(skb, bat_priv, &new_skb);
1057
1058                if (ret == NET_RX_DROP)
1059                        return NET_RX_DROP;
1060
1061                /* packet was buffered for late merge */
1062                if (!new_skb)
1063                        return NET_RX_SUCCESS;
1064
1065                batadv_interface_rx(recv_if->soft_iface, new_skb, recv_if,
1066                                    sizeof(struct batadv_unicast_packet));
1067                return NET_RX_SUCCESS;
1068        }
1069
1070        return batadv_route_unicast_packet(skb, recv_if);
1071}
1072
1073
1074int batadv_recv_bcast_packet(struct sk_buff *skb,
1075                             struct batadv_hard_iface *recv_if)
1076{
1077        struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1078        struct batadv_orig_node *orig_node = NULL;
1079        struct batadv_bcast_packet *bcast_packet;
1080        struct ethhdr *ethhdr;
1081        int hdr_size = sizeof(*bcast_packet);
1082        int ret = NET_RX_DROP;
1083        int32_t seq_diff;
1084
1085        /* drop packet if it has not necessary minimum size */
1086        if (unlikely(!pskb_may_pull(skb, hdr_size)))
1087                goto out;
1088
1089        ethhdr = (struct ethhdr *)skb_mac_header(skb);
1090
1091        /* packet with broadcast indication but unicast recipient */
1092        if (!is_broadcast_ether_addr(ethhdr->h_dest))
1093                goto out;
1094
1095        /* packet with broadcast sender address */
1096        if (is_broadcast_ether_addr(ethhdr->h_source))
1097                goto out;
1098
1099        /* ignore broadcasts sent by myself */
1100        if (batadv_is_my_mac(ethhdr->h_source))
1101                goto out;
1102
1103        bcast_packet = (struct batadv_bcast_packet *)skb->data;
1104
1105        /* ignore broadcasts originated by myself */
1106        if (batadv_is_my_mac(bcast_packet->orig))
1107                goto out;
1108
1109        if (bcast_packet->header.ttl < 2)
1110                goto out;
1111
1112        orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1113
1114        if (!orig_node)
1115                goto out;
1116
1117        spin_lock_bh(&orig_node->bcast_seqno_lock);
1118
1119        /* check whether the packet is a duplicate */
1120        if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1121                            ntohl(bcast_packet->seqno)))
1122                goto spin_unlock;
1123
1124        seq_diff = ntohl(bcast_packet->seqno) - orig_node->last_bcast_seqno;
1125
1126        /* check whether the packet is old and the host just restarted. */
1127        if (batadv_window_protected(bat_priv, seq_diff,
1128                                    &orig_node->bcast_seqno_reset))
1129                goto spin_unlock;
1130
1131        /* mark broadcast in flood history, update window position
1132         * if required.
1133         */
1134        if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1135                orig_node->last_bcast_seqno = ntohl(bcast_packet->seqno);
1136
1137        spin_unlock_bh(&orig_node->bcast_seqno_lock);
1138
1139        /* check whether this has been sent by another originator before */
1140        if (batadv_bla_check_bcast_duplist(bat_priv, bcast_packet, hdr_size))
1141                goto out;
1142
1143        /* rebroadcast packet */
1144        batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1145
1146        /* don't hand the broadcast up if it is from an originator
1147         * from the same backbone.
1148         */
1149        if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1150                goto out;
1151
1152        /* broadcast for me */
1153        batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size);
1154        ret = NET_RX_SUCCESS;
1155        goto out;
1156
1157spin_unlock:
1158        spin_unlock_bh(&orig_node->bcast_seqno_lock);
1159out:
1160        if (orig_node)
1161                batadv_orig_node_free_ref(orig_node);
1162        return ret;
1163}
1164
1165int batadv_recv_vis_packet(struct sk_buff *skb,
1166                           struct batadv_hard_iface *recv_if)
1167{
1168        struct batadv_vis_packet *vis_packet;
1169        struct ethhdr *ethhdr;
1170        struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1171        int hdr_size = sizeof(*vis_packet);
1172
1173        /* keep skb linear */
1174        if (skb_linearize(skb) < 0)
1175                return NET_RX_DROP;
1176
1177        if (unlikely(!pskb_may_pull(skb, hdr_size)))
1178                return NET_RX_DROP;
1179
1180        vis_packet = (struct batadv_vis_packet *)skb->data;
1181        ethhdr = (struct ethhdr *)skb_mac_header(skb);
1182
1183        /* not for me */
1184        if (!batadv_is_my_mac(ethhdr->h_dest))
1185                return NET_RX_DROP;
1186
1187        /* ignore own packets */
1188        if (batadv_is_my_mac(vis_packet->vis_orig))
1189                return NET_RX_DROP;
1190
1191        if (batadv_is_my_mac(vis_packet->sender_orig))
1192                return NET_RX_DROP;
1193
1194        switch (vis_packet->vis_type) {
1195        case BATADV_VIS_TYPE_SERVER_SYNC:
1196                batadv_receive_server_sync_packet(bat_priv, vis_packet,
1197                                                  skb_headlen(skb));
1198                break;
1199
1200        case BATADV_VIS_TYPE_CLIENT_UPDATE:
1201                batadv_receive_client_update_packet(bat_priv, vis_packet,
1202                                                    skb_headlen(skb));
1203                break;
1204
1205        default:        /* ignore unknown packet */
1206                break;
1207        }
1208
1209        /* We take a copy of the data in the packet, so we should
1210         * always free the skbuf.
1211         */
1212        return NET_RX_DROP;
1213}
1214
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