net/batman-adv/routing.c

   1 /* Copyright (C) 2007-2014 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, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "main.h"
  19 #include "routing.h"
  20 #include "send.h"
  21 #include "soft-interface.h"
  22 #include "hard-interface.h"
  23 #include "icmp_socket.h"
  24 #include "translation-table.h"
  25 #include "originator.h"
  26 #include "bridge_loop_avoidance.h"
  27 #include "distributed-arp-table.h"
  28 #include "network-coding.h"
  29 #include "fragmentation.h"
  30
  31 #include <linux/if_vlan.h>
  32
  33 static int batadv_route_unicast_packet(struct sk_buff *skb,
  34                                        struct batadv_hard_iface *recv_if);
  35
  36 /**
  37  * _batadv_update_route - set the router for this originator
  38  * @bat_priv: the bat priv with all the soft interface information
  39  * @orig_node: orig node which is to be configured
  40  * @recv_if: the receive interface for which this route is set
  41  * @neigh_node: neighbor which should be the next router
  42  *
  43  * This function does not perform any error checks
  44  */
  45 static void _batadv_update_route(struct batadv_priv *bat_priv,
  46                                  struct batadv_orig_node *orig_node,
  47                                  struct batadv_hard_iface *recv_if,
  48                                  struct batadv_neigh_node *neigh_node)
  49 {
  50         struct batadv_orig_ifinfo *orig_ifinfo;
  51         struct batadv_neigh_node *curr_router;
  52
  53         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
  54         if (!orig_ifinfo)
  55                 return;
  56
  57         rcu_read_lock();
  58         curr_router = rcu_dereference(orig_ifinfo->router);
  59         if (curr_router && !atomic_inc_not_zero(&curr_router->refcount))
  60                 curr_router = NULL;
  61         rcu_read_unlock();
  62
  63         /* route deleted */
  64         if ((curr_router) && (!neigh_node)) {
  65                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  66                            "Deleting route towards: %pM\n", orig_node->orig);
  67                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
  68                                           "Deleted route towards originator");
  69
  70         /* route added */
  71         } else if ((!curr_router) && (neigh_node)) {
  72                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  73                            "Adding route towards: %pM (via %pM)\n",
  74                            orig_node->orig, neigh_node->addr);
  75         /* route changed */
  76         } else if (neigh_node && curr_router) {
  77                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  78                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
  79                            orig_node->orig, neigh_node->addr,
  80                            curr_router->addr);
  81         }
  82
  83         if (curr_router)
  84                 batadv_neigh_node_free_ref(curr_router);
  85
  86         /* increase refcount of new best neighbor */
  87         if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
  88                 neigh_node = NULL;
  89
  90         spin_lock_bh(&orig_node->neigh_list_lock);
  91         rcu_assign_pointer(orig_ifinfo->router, neigh_node);
  92         spin_unlock_bh(&orig_node->neigh_list_lock);
  93         batadv_orig_ifinfo_free_ref(orig_ifinfo);
  94
  95         /* decrease refcount of previous best neighbor */
  96         if (curr_router)
  97                 batadv_neigh_node_free_ref(curr_router);
  98 }
  99
 100 /**
 101  * batadv_update_route - set the router for this originator
 102  * @bat_priv: the bat priv with all the soft interface information
 103  * @orig_node: orig node which is to be configured
 104  * @recv_if: the receive interface for which this route is set
 105  * @neigh_node: neighbor which should be the next router
 106  */
 107 void batadv_update_route(struct batadv_priv *bat_priv,
 108                          struct batadv_orig_node *orig_node,
 109                          struct batadv_hard_iface *recv_if,
 110                          struct batadv_neigh_node *neigh_node)
 111 {
 112         struct batadv_neigh_node *router = NULL;
 113
 114         if (!orig_node)
 115                 goto out;
 116
 117         router = batadv_orig_router_get(orig_node, recv_if);
 118
 119         if (router != neigh_node)
 120                 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
 121
 122 out:
 123         if (router)
 124                 batadv_neigh_node_free_ref(router);
 125 }
 126
 127 /* checks whether the host restarted and is in the protection time.
 128  * returns:
 129  *  0 if the packet is to be accepted
 130  *  1 if the packet is to be ignored.
 131  */
 132 int batadv_window_protected(struct batadv_priv *bat_priv, int32_t seq_num_diff,
 133                             unsigned long *last_reset)
 134 {
 135         if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
 136             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 137                 if (!batadv_has_timed_out(*last_reset,
 138                                           BATADV_RESET_PROTECTION_MS))
 139                         return 1;
 140
 141                 *last_reset = jiffies;
 142                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 143                            "old packet received, start protection\n");
 144         }
 145
 146         return 0;
 147 }
 148
 149 bool batadv_check_management_packet(struct sk_buff *skb,
 150                                     struct batadv_hard_iface *hard_iface,
 151                                     int header_len)
 152 {
 153         struct ethhdr *ethhdr;
 154
 155         /* drop packet if it has not necessary minimum size */
 156         if (unlikely(!pskb_may_pull(skb, header_len)))
 157                 return false;
 158
 159         ethhdr = eth_hdr(skb);
 160
 161         /* packet with broadcast indication but unicast recipient */
 162         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 163                 return false;
 164
 165         /* packet with broadcast sender address */
 166         if (is_broadcast_ether_addr(ethhdr->h_source))
 167                 return false;
 168
 169         /* create a copy of the skb, if needed, to modify it. */
 170         if (skb_cow(skb, 0) < 0)
 171                 return false;
 172
 173         /* keep skb linear */
 174         if (skb_linearize(skb) < 0)
 175                 return false;
 176
 177         return true;
 178 }
 179
 180 /**
 181  * batadv_recv_my_icmp_packet - receive an icmp packet locally
 182  * @bat_priv: the bat priv with all the soft interface information
 183  * @skb: icmp packet to process
 184  *
 185  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 186  * otherwise.
 187  */
 188 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 189                                       struct sk_buff *skb)
 190 {
 191         struct batadv_hard_iface *primary_if = NULL;
 192         struct batadv_orig_node *orig_node = NULL;
 193         struct batadv_icmp_header *icmph;
 194         int res, ret = NET_RX_DROP;
 195
 196         icmph = (struct batadv_icmp_header *)skb->data;
 197
 198         switch (icmph->msg_type) {
 199         case BATADV_ECHO_REPLY:
 200         case BATADV_DESTINATION_UNREACHABLE:
 201         case BATADV_TTL_EXCEEDED:
 202                 /* receive the packet */
 203                 if (skb_linearize(skb) < 0)
 204                         break;
 205
 206                 batadv_socket_receive_packet(icmph, skb->len);
 207                 break;
 208         case BATADV_ECHO_REQUEST:
 209                 /* answer echo request (ping) */
 210                 primary_if = batadv_primary_if_get_selected(bat_priv);
 211                 if (!primary_if)
 212                         goto out;
 213
 214                 /* get routing information */
 215                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 216                 if (!orig_node)
 217                         goto out;
 218
 219                 /* create a copy of the skb, if needed, to modify it. */
 220                 if (skb_cow(skb, ETH_HLEN) < 0)
 221                         goto out;
 222
 223                 icmph = (struct batadv_icmp_header *)skb->data;
 224
 225                 ether_addr_copy(icmph->dst, icmph->orig);
 226                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
 227                 icmph->msg_type = BATADV_ECHO_REPLY;
 228                 icmph->ttl = BATADV_TTL;
 229
 230                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 231                 if (res != NET_XMIT_DROP)
 232                         ret = NET_RX_SUCCESS;
 233
 234                 break;
 235         default:
 236                 /* drop unknown type */
 237                 goto out;
 238         }
 239 out:
 240         if (primary_if)
 241                 batadv_hardif_free_ref(primary_if);
 242         if (orig_node)
 243                 batadv_orig_node_free_ref(orig_node);
 244         return ret;
 245 }
 246
 247 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 248                                          struct sk_buff *skb)
 249 {
 250         struct batadv_hard_iface *primary_if = NULL;
 251         struct batadv_orig_node *orig_node = NULL;
 252         struct batadv_icmp_packet *icmp_packet;
 253         int ret = NET_RX_DROP;
 254
 255         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 256
 257         /* send TTL exceeded if packet is an echo request (traceroute) */
 258         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 259                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 260                          icmp_packet->orig, icmp_packet->dst);
 261                 goto out;
 262         }
 263
 264         primary_if = batadv_primary_if_get_selected(bat_priv);
 265         if (!primary_if)
 266                 goto out;
 267
 268         /* get routing information */
 269         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 270         if (!orig_node)
 271                 goto out;
 272
 273         /* create a copy of the skb, if needed, to modify it. */
 274         if (skb_cow(skb, ETH_HLEN) < 0)
 275                 goto out;
 276
 277         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 278
 279         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
 280         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
 281         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 282         icmp_packet->ttl = BATADV_TTL;
 283
 284         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 285                 ret = NET_RX_SUCCESS;
 286
 287 out:
 288         if (primary_if)
 289                 batadv_hardif_free_ref(primary_if);
 290         if (orig_node)
 291                 batadv_orig_node_free_ref(orig_node);
 292         return ret;
 293 }
 294
 295
 296 int batadv_recv_icmp_packet(struct sk_buff *skb,
 297                             struct batadv_hard_iface *recv_if)
 298 {
 299         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 300         struct batadv_icmp_header *icmph;
 301         struct batadv_icmp_packet_rr *icmp_packet_rr;
 302         struct ethhdr *ethhdr;
 303         struct batadv_orig_node *orig_node = NULL;
 304         int hdr_size = sizeof(struct batadv_icmp_header);
 305         int ret = NET_RX_DROP;
 306
 307         /* drop packet if it has not necessary minimum size */
 308         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 309                 goto out;
 310
 311         ethhdr = eth_hdr(skb);
 312
 313         /* packet with unicast indication but broadcast recipient */
 314         if (is_broadcast_ether_addr(ethhdr->h_dest))
 315                 goto out;
 316
 317         /* packet with broadcast sender address */
 318         if (is_broadcast_ether_addr(ethhdr->h_source))
 319                 goto out;
 320
 321         /* not for me */
 322         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 323                 goto out;
 324
 325         icmph = (struct batadv_icmp_header *)skb->data;
 326
 327         /* add record route information if not full */
 328         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 329              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 330             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 331                 if (skb_linearize(skb) < 0)
 332                         goto out;
 333
 334                 /* create a copy of the skb, if needed, to modify it. */
 335                 if (skb_cow(skb, ETH_HLEN) < 0)
 336                         goto out;
 337
 338                 icmph = (struct batadv_icmp_header *)skb->data;
 339                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 340                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 341                         goto out;
 342
 343                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
 344                                 ethhdr->h_dest);
 345                 icmp_packet_rr->rr_cur++;
 346         }
 347
 348         /* packet for me */
 349         if (batadv_is_my_mac(bat_priv, icmph->dst))
 350                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 351
 352         /* TTL exceeded */
 353         if (icmph->ttl < 2)
 354                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 355
 356         /* get routing information */
 357         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 358         if (!orig_node)
 359                 goto out;
 360
 361         /* create a copy of the skb, if needed, to modify it. */
 362         if (skb_cow(skb, ETH_HLEN) < 0)
 363                 goto out;
 364
 365         icmph = (struct batadv_icmp_header *)skb->data;
 366
 367         /* decrement ttl */
 368         icmph->ttl--;
 369
 370         /* route it */
 371         if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
 372                 ret = NET_RX_SUCCESS;
 373
 374 out:
 375         if (orig_node)
 376                 batadv_orig_node_free_ref(orig_node);
 377         return ret;
 378 }
 379
 380 /**
 381  * batadv_check_unicast_packet - Check for malformed unicast packets
 382  * @bat_priv: the bat priv with all the soft interface information
 383  * @skb: packet to check
 384  * @hdr_size: size of header to pull
 385  *
 386  * Check for short header and bad addresses in given packet. Returns negative
 387  * value when check fails and 0 otherwise. The negative value depends on the
 388  * reason: -ENODATA for bad header, -EBADR for broadcast destination or source,
 389  * and -EREMOTE for non-local (other host) destination.
 390  */
 391 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 392                                        struct sk_buff *skb, int hdr_size)
 393 {
 394         struct ethhdr *ethhdr;
 395
 396         /* drop packet if it has not necessary minimum size */
 397         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 398                 return -ENODATA;
 399
 400         ethhdr = eth_hdr(skb);
 401
 402         /* packet with unicast indication but broadcast recipient */
 403         if (is_broadcast_ether_addr(ethhdr->h_dest))
 404                 return -EBADR;
 405
 406         /* packet with broadcast sender address */
 407         if (is_broadcast_ether_addr(ethhdr->h_source))
 408                 return -EBADR;
 409
 410         /* not for me */
 411         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 412                 return -EREMOTE;
 413
 414         return 0;
 415 }
 416
 417 /**
 418  * batadv_find_router - find a suitable router for this originator
 419  * @bat_priv: the bat priv with all the soft interface information
 420  * @orig_node: the destination node
 421  * @recv_if: pointer to interface this packet was received on
 422  *
 423  * Returns the router which should be used for this orig_node on
 424  * this interface, or NULL if not available.
 425  */
 426 struct batadv_neigh_node *
 427 batadv_find_router(struct batadv_priv *bat_priv,
 428                    struct batadv_orig_node *orig_node,
 429                    struct batadv_hard_iface *recv_if)
 430 {
 431         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 432         struct batadv_neigh_node *first_candidate_router = NULL;
 433         struct batadv_neigh_node *next_candidate_router = NULL;
 434         struct batadv_neigh_node *router, *cand_router = NULL;
 435         struct batadv_neigh_node *last_cand_router = NULL;
 436         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
 437         struct batadv_orig_ifinfo *next_candidate = NULL;
 438         struct batadv_orig_ifinfo *last_candidate;
 439         bool last_candidate_found = false;
 440
 441         if (!orig_node)
 442                 return NULL;
 443
 444         router = batadv_orig_router_get(orig_node, recv_if);
 445
 446         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 447          * and if activated.
 448          */
 449         if (recv_if == BATADV_IF_DEFAULT || !atomic_read(&bat_priv->bonding) ||
 450             !router)
 451                 return router;
 452
 453         /* bonding: loop through the list of possible routers found
 454          * for the various outgoing interfaces and find a candidate after
 455          * the last chosen bonding candidate (next_candidate). If no such
 456          * router is found, use the first candidate found (the previously
 457          * chosen bonding candidate might have been the last one in the list).
 458          * If this can't be found either, return the previously choosen
 459          * router - obviously there are no other candidates.
 460          */
 461         rcu_read_lock();
 462         last_candidate = orig_node->last_bonding_candidate;
 463         if (last_candidate)
 464                 last_cand_router = rcu_dereference(last_candidate->router);
 465
 466         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 467                 /* acquire some structures and references ... */
 468                 if (!atomic_inc_not_zero(&cand->refcount))
 469                         continue;
 470
 471                 cand_router = rcu_dereference(cand->router);
 472                 if (!cand_router)
 473                         goto next;
 474
 475                 if (!atomic_inc_not_zero(&cand_router->refcount)) {
 476                         cand_router = NULL;
 477                         goto next;
 478                 }
 479
 480                 /* alternative candidate should be good enough to be
 481                  * considered
 482                  */
 483                 if (!bao->bat_neigh_is_equiv_or_better(cand_router,
 484                                                        cand->if_outgoing,
 485                                                        router, recv_if))
 486                         goto next;
 487
 488                 /* don't use the same router twice */
 489                 if (last_cand_router == cand_router)
 490                         goto next;
 491
 492                 /* mark the first possible candidate */
 493                 if (!first_candidate) {
 494                         atomic_inc(&cand_router->refcount);
 495                         atomic_inc(&cand->refcount);
 496                         first_candidate = cand;
 497                         first_candidate_router = cand_router;
 498                 }
 499
 500                 /* check if the loop has already passed the previously selected
 501                  * candidate ... this function should select the next candidate
 502                  * AFTER the previously used bonding candidate.
 503                  */
 504                 if (!last_candidate || last_candidate_found) {
 505                         next_candidate = cand;
 506                         next_candidate_router = cand_router;
 507                         break;
 508                 }
 509
 510                 if (last_candidate == cand)
 511                         last_candidate_found = true;
 512 next:
 513                 /* free references */
 514                 if (cand_router) {
 515                         batadv_neigh_node_free_ref(cand_router);
 516                         cand_router = NULL;
 517                 }
 518                 batadv_orig_ifinfo_free_ref(cand);
 519         }
 520         rcu_read_unlock();
 521
 522         /* last_bonding_candidate is reset below, remove the old reference. */
 523         if (orig_node->last_bonding_candidate)
 524                 batadv_orig_ifinfo_free_ref(orig_node->last_bonding_candidate);
 525
 526         /* After finding candidates, handle the three cases:
 527          * 1) there is a next candidate, use that
 528          * 2) there is no next candidate, use the first of the list
 529          * 3) there is no candidate at all, return the default router
 530          */
 531         if (next_candidate) {
 532                 batadv_neigh_node_free_ref(router);
 533
 534                 /* remove references to first candidate, we don't need it. */
 535                 if (first_candidate) {
 536                         batadv_neigh_node_free_ref(first_candidate_router);
 537                         batadv_orig_ifinfo_free_ref(first_candidate);
 538                 }
 539                 router = next_candidate_router;
 540                 orig_node->last_bonding_candidate = next_candidate;
 541         } else if (first_candidate) {
 542                 batadv_neigh_node_free_ref(router);
 543
 544                 /* refcounting has already been done in the loop above. */
 545                 router = first_candidate_router;
 546                 orig_node->last_bonding_candidate = first_candidate;
 547         } else {
 548                 orig_node->last_bonding_candidate = NULL;
 549         }
 550
 551         return router;
 552 }
 553
 554 static int batadv_route_unicast_packet(struct sk_buff *skb,
 555                                        struct batadv_hard_iface *recv_if)
 556 {
 557         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 558         struct batadv_orig_node *orig_node = NULL;
 559         struct batadv_unicast_packet *unicast_packet;
 560         struct ethhdr *ethhdr = eth_hdr(skb);
 561         int res, hdr_len, ret = NET_RX_DROP;
 562
 563         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 564
 565         /* TTL exceeded */
 566         if (unicast_packet->ttl < 2) {
 567                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 568                          ethhdr->h_source, unicast_packet->dest);
 569                 goto out;
 570         }
 571
 572         /* get routing information */
 573         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 574
 575         if (!orig_node)
 576                 goto out;
 577
 578         /* create a copy of the skb, if needed, to modify it. */
 579         if (skb_cow(skb, ETH_HLEN) < 0)
 580                 goto out;
 581
 582         /* decrement ttl */
 583         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 584         unicast_packet->ttl--;
 585
 586         switch (unicast_packet->packet_type) {
 587         case BATADV_UNICAST_4ADDR:
 588                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 589                 break;
 590         case BATADV_UNICAST:
 591                 hdr_len = sizeof(struct batadv_unicast_packet);
 592                 break;
 593         default:
 594                 /* other packet types not supported - yet */
 595                 hdr_len = -1;
 596                 break;
 597         }
 598
 599         if (hdr_len > 0)
 600                 batadv_skb_set_priority(skb, hdr_len);
 601
 602         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 603
 604         /* translate transmit result into receive result */
 605         if (res == NET_XMIT_SUCCESS) {
 606                 /* skb was transmitted and consumed */
 607                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 608                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 609                                    skb->len + ETH_HLEN);
 610
 611                 ret = NET_RX_SUCCESS;
 612         } else if (res == NET_XMIT_POLICED) {
 613                 /* skb was buffered and consumed */
 614                 ret = NET_RX_SUCCESS;
 615         }
 616
 617 out:
 618         if (orig_node)
 619                 batadv_orig_node_free_ref(orig_node);
 620         return ret;
 621 }
 622
 623 /**
 624  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 625  * @bat_priv: the bat priv with all the soft interface information
 626  * @unicast_packet: the unicast header to be updated
 627  * @dst_addr: the payload destination
 628  * @vid: VLAN identifier
 629  *
 630  * Search the translation table for dst_addr and update the unicast header with
 631  * the new corresponding information (originator address where the destination
 632  * client currently is and its known TTVN)
 633  *
 634  * Returns true if the packet header has been updated, false otherwise
 635  */
 636 static bool
 637 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 638                               struct batadv_unicast_packet *unicast_packet,
 639                               uint8_t *dst_addr, unsigned short vid)
 640 {
 641         struct batadv_orig_node *orig_node = NULL;
 642         struct batadv_hard_iface *primary_if = NULL;
 643         bool ret = false;
 644         uint8_t *orig_addr, orig_ttvn;
 645
 646         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 647                 primary_if = batadv_primary_if_get_selected(bat_priv);
 648                 if (!primary_if)
 649                         goto out;
 650                 orig_addr = primary_if->net_dev->dev_addr;
 651                 orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 652         } else {
 653                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 654                                                      vid);
 655                 if (!orig_node)
 656                         goto out;
 657
 658                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 659                         goto out;
 660
 661                 orig_addr = orig_node->orig;
 662                 orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 663         }
 664
 665         /* update the packet header */
 666         ether_addr_copy(unicast_packet->dest, orig_addr);
 667         unicast_packet->ttvn = orig_ttvn;
 668
 669         ret = true;
 670 out:
 671         if (primary_if)
 672                 batadv_hardif_free_ref(primary_if);
 673         if (orig_node)
 674                 batadv_orig_node_free_ref(orig_node);
 675
 676         return ret;
 677 }
 678
 679 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 680                                      struct sk_buff *skb, int hdr_len) {
 681         struct batadv_unicast_packet *unicast_packet;
 682         struct batadv_hard_iface *primary_if;
 683         struct batadv_orig_node *orig_node;
 684         uint8_t curr_ttvn, old_ttvn;
 685         struct ethhdr *ethhdr;
 686         unsigned short vid;
 687         int is_old_ttvn;
 688
 689         /* check if there is enough data before accessing it */
 690         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 691                 return 0;
 692
 693         /* create a copy of the skb (in case of for re-routing) to modify it. */
 694         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 695                 return 0;
 696
 697         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 698         vid = batadv_get_vid(skb, hdr_len);
 699         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 700
 701         /* check if the destination client was served by this node and it is now
 702          * roaming. In this case, it means that the node has got a ROAM_ADV
 703          * message and that it knows the new destination in the mesh to re-route
 704          * the packet to
 705          */
 706         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 707                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 708                                                   ethhdr->h_dest, vid))
 709                         net_ratelimited_function(batadv_dbg, BATADV_DBG_TT,
 710                                                  bat_priv,
 711                                                  "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 712                                                  unicast_packet->dest,
 713                                                  ethhdr->h_dest);
 714                 /* at this point the mesh destination should have been
 715                  * substituted with the originator address found in the global
 716                  * table. If not, let the packet go untouched anyway because
 717                  * there is nothing the node can do
 718                  */
 719                 return 1;
 720         }
 721
 722         /* retrieve the TTVN known by this node for the packet destination. This
 723          * value is used later to check if the node which sent (or re-routed
 724          * last time) the packet had an updated information or not
 725          */
 726         curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 727         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 728                 orig_node = batadv_orig_hash_find(bat_priv,
 729                                                   unicast_packet->dest);
 730                 /* if it is not possible to find the orig_node representing the
 731                  * destination, the packet can immediately be dropped as it will
 732                  * not be possible to deliver it
 733                  */
 734                 if (!orig_node)
 735                         return 0;
 736
 737                 curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 738                 batadv_orig_node_free_ref(orig_node);
 739         }
 740
 741         /* check if the TTVN contained in the packet is fresher than what the
 742          * node knows
 743          */
 744         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 745         if (!is_old_ttvn)
 746                 return 1;
 747
 748         old_ttvn = unicast_packet->ttvn;
 749         /* the packet was forged based on outdated network information. Its
 750          * destination can possibly be updated and forwarded towards the new
 751          * target host
 752          */
 753         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 754                                           ethhdr->h_dest, vid)) {
 755                 net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv,
 756                                          "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 757                                          unicast_packet->dest, ethhdr->h_dest,
 758                                          old_ttvn, curr_ttvn);
 759                 return 1;
 760         }
 761
 762         /* the packet has not been re-routed: either the destination is
 763          * currently served by this node or there is no destination at all and
 764          * it is possible to drop the packet
 765          */
 766         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 767                 return 0;
 768
 769         /* update the header in order to let the packet be delivered to this
 770          * node's soft interface
 771          */
 772         primary_if = batadv_primary_if_get_selected(bat_priv);
 773         if (!primary_if)
 774                 return 0;
 775
 776         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
 777
 778         batadv_hardif_free_ref(primary_if);
 779
 780         unicast_packet->ttvn = curr_ttvn;
 781
 782         return 1;
 783 }
 784
 785 /**
 786  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 787  *      are in the unicast number space but not yet known to the implementation
 788  * @skb: unicast tvlv packet to process
 789  * @recv_if: pointer to interface this packet was received on
 790  *
 791  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 792  * otherwise.
 793  */
 794 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 795                                          struct batadv_hard_iface *recv_if)
 796 {
 797         struct batadv_unicast_packet *unicast_packet;
 798         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 799         int check, hdr_size = sizeof(*unicast_packet);
 800
 801         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 802         if (check < 0)
 803                 return NET_RX_DROP;
 804
 805         /* we don't know about this type, drop it. */
 806         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 807         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 808                 return NET_RX_DROP;
 809
 810         return batadv_route_unicast_packet(skb, recv_if);
 811 }
 812
 813 int batadv_recv_unicast_packet(struct sk_buff *skb,
 814                                struct batadv_hard_iface *recv_if)
 815 {
 816         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 817         struct batadv_unicast_packet *unicast_packet;
 818         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 819         uint8_t *orig_addr;
 820         struct batadv_orig_node *orig_node = NULL;
 821         int check, hdr_size = sizeof(*unicast_packet);
 822         bool is4addr;
 823
 824         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 825         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 826
 827         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 828         /* the caller function should have already pulled 2 bytes */
 829         if (is4addr)
 830                 hdr_size = sizeof(*unicast_4addr_packet);
 831
 832         /* function returns -EREMOTE for promiscuous packets */
 833         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 834
 835         /* Even though the packet is not for us, we might save it to use for
 836          * decoding a later received coded packet
 837          */
 838         if (check == -EREMOTE)
 839                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 840
 841         if (check < 0)
 842                 return NET_RX_DROP;
 843         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 844                 return NET_RX_DROP;
 845
 846         /* packet for me */
 847         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 848                 if (is4addr) {
 849                         batadv_dat_inc_counter(bat_priv,
 850                                                unicast_4addr_packet->subtype);
 851                         orig_addr = unicast_4addr_packet->src;
 852                         orig_node = batadv_orig_hash_find(bat_priv, orig_addr);
 853                 }
 854
 855                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 856                                                           hdr_size))
 857                         goto rx_success;
 858                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 859                                                         hdr_size))
 860                         goto rx_success;
 861
 862                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
 863                                     orig_node);
 864
 865 rx_success:
 866                 if (orig_node)
 867                         batadv_orig_node_free_ref(orig_node);
 868
 869                 return NET_RX_SUCCESS;
 870         }
 871
 872         return batadv_route_unicast_packet(skb, recv_if);
 873 }
 874
 875 /**
 876  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
 877  * @skb: unicast tvlv packet to process
 878  * @recv_if: pointer to interface this packet was received on
 879  * @dst_addr: the payload destination
 880  *
 881  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 882  * otherwise.
 883  */
 884 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
 885                              struct batadv_hard_iface *recv_if)
 886 {
 887         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 888         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
 889         unsigned char *tvlv_buff;
 890         uint16_t tvlv_buff_len;
 891         int hdr_size = sizeof(*unicast_tvlv_packet);
 892         int ret = NET_RX_DROP;
 893
 894         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
 895                 return NET_RX_DROP;
 896
 897         /* the header is likely to be modified while forwarding */
 898         if (skb_cow(skb, hdr_size) < 0)
 899                 return NET_RX_DROP;
 900
 901         /* packet needs to be linearized to access the tvlv content */
 902         if (skb_linearize(skb) < 0)
 903                 return NET_RX_DROP;
 904
 905         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
 906
 907         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
 908         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
 909
 910         if (tvlv_buff_len > skb->len - hdr_size)
 911                 return NET_RX_DROP;
 912
 913         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
 914                                              unicast_tvlv_packet->src,
 915                                              unicast_tvlv_packet->dst,
 916                                              tvlv_buff, tvlv_buff_len);
 917
 918         if (ret != NET_RX_SUCCESS)
 919                 ret = batadv_route_unicast_packet(skb, recv_if);
 920         else
 921                 consume_skb(skb);
 922
 923         return ret;
 924 }
 925
 926 /**
 927  * batadv_recv_frag_packet - process received fragment
 928  * @skb: the received fragment
 929  * @recv_if: interface that the skb is received on
 930  *
 931  * This function does one of the three following things: 1) Forward fragment, if
 932  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
 933  * lack further fragments; 3) Merge fragments, if we have all needed parts.
 934  *
 935  * Return NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
 936  */
 937 int batadv_recv_frag_packet(struct sk_buff *skb,
 938                             struct batadv_hard_iface *recv_if)
 939 {
 940         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 941         struct batadv_orig_node *orig_node_src = NULL;
 942         struct batadv_frag_packet *frag_packet;
 943         int ret = NET_RX_DROP;
 944
 945         if (batadv_check_unicast_packet(bat_priv, skb,
 946                                         sizeof(*frag_packet)) < 0)
 947                 goto out;
 948
 949         frag_packet = (struct batadv_frag_packet *)skb->data;
 950         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
 951         if (!orig_node_src)
 952                 goto out;
 953
 954         /* Route the fragment if it is not for us and too big to be merged. */
 955         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
 956             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
 957                 ret = NET_RX_SUCCESS;
 958                 goto out;
 959         }
 960
 961         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
 962         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
 963
 964         /* Add fragment to buffer and merge if possible. */
 965         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
 966                 goto out;
 967
 968         /* Deliver merged packet to the appropriate handler, if it was
 969          * merged
 970          */
 971         if (skb)
 972                 batadv_batman_skb_recv(skb, recv_if->net_dev,
 973                                        &recv_if->batman_adv_ptype, NULL);
 974
 975         ret = NET_RX_SUCCESS;
 976
 977 out:
 978         if (orig_node_src)
 979                 batadv_orig_node_free_ref(orig_node_src);
 980
 981         return ret;
 982 }
 983
 984 int batadv_recv_bcast_packet(struct sk_buff *skb,
 985                              struct batadv_hard_iface *recv_if)
 986 {
 987         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 988         struct batadv_orig_node *orig_node = NULL;
 989         struct batadv_bcast_packet *bcast_packet;
 990         struct ethhdr *ethhdr;
 991         int hdr_size = sizeof(*bcast_packet);
 992         int ret = NET_RX_DROP;
 993         int32_t seq_diff;
 994         uint32_t seqno;
 995
 996         /* drop packet if it has not necessary minimum size */
 997         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 998                 goto out;
 999
1000         ethhdr = eth_hdr(skb);
1001
1002         /* packet with broadcast indication but unicast recipient */
1003         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1004                 goto out;
1005
1006         /* packet with broadcast sender address */
1007         if (is_broadcast_ether_addr(ethhdr->h_source))
1008                 goto out;
1009
1010         /* ignore broadcasts sent by myself */
1011         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1012                 goto out;
1013
1014         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1015
1016         /* ignore broadcasts originated by myself */
1017         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1018                 goto out;
1019
1020         if (bcast_packet->ttl < 2)
1021                 goto out;
1022
1023         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1024
1025         if (!orig_node)
1026                 goto out;
1027
1028         spin_lock_bh(&orig_node->bcast_seqno_lock);
1029
1030         seqno = ntohl(bcast_packet->seqno);
1031         /* check whether the packet is a duplicate */
1032         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1033                             seqno))
1034                 goto spin_unlock;
1035
1036         seq_diff = seqno - orig_node->last_bcast_seqno;
1037
1038         /* check whether the packet is old and the host just restarted. */
1039         if (batadv_window_protected(bat_priv, seq_diff,
1040                                     &orig_node->bcast_seqno_reset))
1041                 goto spin_unlock;
1042
1043         /* mark broadcast in flood history, update window position
1044          * if required.
1045          */
1046         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1047                 orig_node->last_bcast_seqno = seqno;
1048
1049         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1050
1051         /* check whether this has been sent by another originator before */
1052         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1053                 goto out;
1054
1055         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1056
1057         /* rebroadcast packet */
1058         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1059
1060         /* don't hand the broadcast up if it is from an originator
1061          * from the same backbone.
1062          */
1063         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1064                 goto out;
1065
1066         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1067                 goto rx_success;
1068         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1069                 goto rx_success;
1070
1071         /* broadcast for me */
1072         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1073                             orig_node);
1074
1075 rx_success:
1076         ret = NET_RX_SUCCESS;
1077         goto out;
1078
1079 spin_unlock:
1080         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1081 out:
1082         if (orig_node)
1083                 batadv_orig_node_free_ref(orig_node);
1084         return ret;
1085 }