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         if (!router)
 447                 return router;
 448
 449         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 450          * and if activated.
 451          */
 452         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
 453                 return router;
 454
 455         /* bonding: loop through the list of possible routers found
 456          * for the various outgoing interfaces and find a candidate after
 457          * the last chosen bonding candidate (next_candidate). If no such
 458          * router is found, use the first candidate found (the previously
 459          * chosen bonding candidate might have been the last one in the list).
 460          * If this can't be found either, return the previously choosen
 461          * router - obviously there are no other candidates.
 462          */
 463         rcu_read_lock();
 464         last_candidate = orig_node->last_bonding_candidate;
 465         if (last_candidate)
 466                 last_cand_router = rcu_dereference(last_candidate->router);
 467
 468         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 469                 /* acquire some structures and references ... */
 470                 if (!atomic_inc_not_zero(&cand->refcount))
 471                         continue;
 472
 473                 cand_router = rcu_dereference(cand->router);
 474                 if (!cand_router)
 475                         goto next;
 476
 477                 if (!atomic_inc_not_zero(&cand_router->refcount)) {
 478                         cand_router = NULL;
 479                         goto next;
 480                 }
 481
 482                 /* alternative candidate should be good enough to be
 483                  * considered
 484                  */
 485                 if (!bao->bat_neigh_is_equiv_or_better(cand_router,
 486                                                        cand->if_outgoing,
 487                                                        router, recv_if))
 488                         goto next;
 489
 490                 /* don't use the same router twice */
 491                 if (last_cand_router == cand_router)
 492                         goto next;
 493
 494                 /* mark the first possible candidate */
 495                 if (!first_candidate) {
 496                         atomic_inc(&cand_router->refcount);
 497                         atomic_inc(&cand->refcount);
 498                         first_candidate = cand;
 499                         first_candidate_router = cand_router;
 500                 }
 501
 502                 /* check if the loop has already passed the previously selected
 503                  * candidate ... this function should select the next candidate
 504                  * AFTER the previously used bonding candidate.
 505                  */
 506                 if (!last_candidate || last_candidate_found) {
 507                         next_candidate = cand;
 508                         next_candidate_router = cand_router;
 509                         break;
 510                 }
 511
 512                 if (last_candidate == cand)
 513                         last_candidate_found = true;
 514 next:
 515                 /* free references */
 516                 if (cand_router) {
 517                         batadv_neigh_node_free_ref(cand_router);
 518                         cand_router = NULL;
 519                 }
 520                 batadv_orig_ifinfo_free_ref(cand);
 521         }
 522         rcu_read_unlock();
 523
 524         /* last_bonding_candidate is reset below, remove the old reference. */
 525         if (orig_node->last_bonding_candidate)
 526                 batadv_orig_ifinfo_free_ref(orig_node->last_bonding_candidate);
 527
 528         /* After finding candidates, handle the three cases:
 529          * 1) there is a next candidate, use that
 530          * 2) there is no next candidate, use the first of the list
 531          * 3) there is no candidate at all, return the default router
 532          */
 533         if (next_candidate) {
 534                 batadv_neigh_node_free_ref(router);
 535
 536                 /* remove references to first candidate, we don't need it. */
 537                 if (first_candidate) {
 538                         batadv_neigh_node_free_ref(first_candidate_router);
 539                         batadv_orig_ifinfo_free_ref(first_candidate);
 540                 }
 541                 router = next_candidate_router;
 542                 orig_node->last_bonding_candidate = next_candidate;
 543         } else if (first_candidate) {
 544                 batadv_neigh_node_free_ref(router);
 545
 546                 /* refcounting has already been done in the loop above. */
 547                 router = first_candidate_router;
 548                 orig_node->last_bonding_candidate = first_candidate;
 549         } else {
 550                 orig_node->last_bonding_candidate = NULL;
 551         }
 552
 553         return router;
 554 }
 555
 556 static int batadv_route_unicast_packet(struct sk_buff *skb,
 557                                        struct batadv_hard_iface *recv_if)
 558 {
 559         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 560         struct batadv_orig_node *orig_node = NULL;
 561         struct batadv_unicast_packet *unicast_packet;
 562         struct ethhdr *ethhdr = eth_hdr(skb);
 563         int res, hdr_len, ret = NET_RX_DROP;
 564
 565         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 566
 567         /* TTL exceeded */
 568         if (unicast_packet->ttl < 2) {
 569                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 570                          ethhdr->h_source, unicast_packet->dest);
 571                 goto out;
 572         }
 573
 574         /* get routing information */
 575         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 576
 577         if (!orig_node)
 578                 goto out;
 579
 580         /* create a copy of the skb, if needed, to modify it. */
 581         if (skb_cow(skb, ETH_HLEN) < 0)
 582                 goto out;
 583
 584         /* decrement ttl */
 585         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 586         unicast_packet->ttl--;
 587
 588         switch (unicast_packet->packet_type) {
 589         case BATADV_UNICAST_4ADDR:
 590                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 591                 break;
 592         case BATADV_UNICAST:
 593                 hdr_len = sizeof(struct batadv_unicast_packet);
 594                 break;
 595         default:
 596                 /* other packet types not supported - yet */
 597                 hdr_len = -1;
 598                 break;
 599         }
 600
 601         if (hdr_len > 0)
 602                 batadv_skb_set_priority(skb, hdr_len);
 603
 604         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 605
 606         /* translate transmit result into receive result */
 607         if (res == NET_XMIT_SUCCESS) {
 608                 /* skb was transmitted and consumed */
 609                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 610                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 611                                    skb->len + ETH_HLEN);
 612
 613                 ret = NET_RX_SUCCESS;
 614         } else if (res == NET_XMIT_POLICED) {
 615                 /* skb was buffered and consumed */
 616                 ret = NET_RX_SUCCESS;
 617         }
 618
 619 out:
 620         if (orig_node)
 621                 batadv_orig_node_free_ref(orig_node);
 622         return ret;
 623 }
 624
 625 /**
 626  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 627  * @bat_priv: the bat priv with all the soft interface information
 628  * @unicast_packet: the unicast header to be updated
 629  * @dst_addr: the payload destination
 630  * @vid: VLAN identifier
 631  *
 632  * Search the translation table for dst_addr and update the unicast header with
 633  * the new corresponding information (originator address where the destination
 634  * client currently is and its known TTVN)
 635  *
 636  * Returns true if the packet header has been updated, false otherwise
 637  */
 638 static bool
 639 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 640                               struct batadv_unicast_packet *unicast_packet,
 641                               uint8_t *dst_addr, unsigned short vid)
 642 {
 643         struct batadv_orig_node *orig_node = NULL;
 644         struct batadv_hard_iface *primary_if = NULL;
 645         bool ret = false;
 646         uint8_t *orig_addr, orig_ttvn;
 647
 648         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 649                 primary_if = batadv_primary_if_get_selected(bat_priv);
 650                 if (!primary_if)
 651                         goto out;
 652                 orig_addr = primary_if->net_dev->dev_addr;
 653                 orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 654         } else {
 655                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 656                                                      vid);
 657                 if (!orig_node)
 658                         goto out;
 659
 660                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 661                         goto out;
 662
 663                 orig_addr = orig_node->orig;
 664                 orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 665         }
 666
 667         /* update the packet header */
 668         ether_addr_copy(unicast_packet->dest, orig_addr);
 669         unicast_packet->ttvn = orig_ttvn;
 670
 671         ret = true;
 672 out:
 673         if (primary_if)
 674                 batadv_hardif_free_ref(primary_if);
 675         if (orig_node)
 676                 batadv_orig_node_free_ref(orig_node);
 677
 678         return ret;
 679 }
 680
 681 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 682                                      struct sk_buff *skb, int hdr_len) {
 683         struct batadv_unicast_packet *unicast_packet;
 684         struct batadv_hard_iface *primary_if;
 685         struct batadv_orig_node *orig_node;
 686         uint8_t curr_ttvn, old_ttvn;
 687         struct ethhdr *ethhdr;
 688         unsigned short vid;
 689         int is_old_ttvn;
 690
 691         /* check if there is enough data before accessing it */
 692         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 693                 return 0;
 694
 695         /* create a copy of the skb (in case of for re-routing) to modify it. */
 696         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 697                 return 0;
 698
 699         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 700         vid = batadv_get_vid(skb, hdr_len);
 701         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 702
 703         /* check if the destination client was served by this node and it is now
 704          * roaming. In this case, it means that the node has got a ROAM_ADV
 705          * message and that it knows the new destination in the mesh to re-route
 706          * the packet to
 707          */
 708         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 709                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 710                                                   ethhdr->h_dest, vid))
 711                         batadv_dbg_ratelimited(BATADV_DBG_TT,
 712                                                bat_priv,
 713                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 714                                                unicast_packet->dest,
 715                                                ethhdr->h_dest);
 716                 /* at this point the mesh destination should have been
 717                  * substituted with the originator address found in the global
 718                  * table. If not, let the packet go untouched anyway because
 719                  * there is nothing the node can do
 720                  */
 721                 return 1;
 722         }
 723
 724         /* retrieve the TTVN known by this node for the packet destination. This
 725          * value is used later to check if the node which sent (or re-routed
 726          * last time) the packet had an updated information or not
 727          */
 728         curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 729         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 730                 orig_node = batadv_orig_hash_find(bat_priv,
 731                                                   unicast_packet->dest);
 732                 /* if it is not possible to find the orig_node representing the
 733                  * destination, the packet can immediately be dropped as it will
 734                  * not be possible to deliver it
 735                  */
 736                 if (!orig_node)
 737                         return 0;
 738
 739                 curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 740                 batadv_orig_node_free_ref(orig_node);
 741         }
 742
 743         /* check if the TTVN contained in the packet is fresher than what the
 744          * node knows
 745          */
 746         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 747         if (!is_old_ttvn)
 748                 return 1;
 749
 750         old_ttvn = unicast_packet->ttvn;
 751         /* the packet was forged based on outdated network information. Its
 752          * destination can possibly be updated and forwarded towards the new
 753          * target host
 754          */
 755         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 756                                           ethhdr->h_dest, vid)) {
 757                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
 758                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 759                                        unicast_packet->dest, ethhdr->h_dest,
 760                                        old_ttvn, curr_ttvn);
 761                 return 1;
 762         }
 763
 764         /* the packet has not been re-routed: either the destination is
 765          * currently served by this node or there is no destination at all and
 766          * it is possible to drop the packet
 767          */
 768         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 769                 return 0;
 770
 771         /* update the header in order to let the packet be delivered to this
 772          * node's soft interface
 773          */
 774         primary_if = batadv_primary_if_get_selected(bat_priv);
 775         if (!primary_if)
 776                 return 0;
 777
 778         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
 779
 780         batadv_hardif_free_ref(primary_if);
 781
 782         unicast_packet->ttvn = curr_ttvn;
 783
 784         return 1;
 785 }
 786
 787 /**
 788  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 789  *      are in the unicast number space but not yet known to the implementation
 790  * @skb: unicast tvlv packet to process
 791  * @recv_if: pointer to interface this packet was received on
 792  *
 793  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 794  * otherwise.
 795  */
 796 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 797                                          struct batadv_hard_iface *recv_if)
 798 {
 799         struct batadv_unicast_packet *unicast_packet;
 800         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 801         int check, hdr_size = sizeof(*unicast_packet);
 802
 803         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 804         if (check < 0)
 805                 return NET_RX_DROP;
 806
 807         /* we don't know about this type, drop it. */
 808         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 809         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 810                 return NET_RX_DROP;
 811
 812         return batadv_route_unicast_packet(skb, recv_if);
 813 }
 814
 815 int batadv_recv_unicast_packet(struct sk_buff *skb,
 816                                struct batadv_hard_iface *recv_if)
 817 {
 818         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 819         struct batadv_unicast_packet *unicast_packet;
 820         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 821         uint8_t *orig_addr;
 822         struct batadv_orig_node *orig_node = NULL;
 823         int check, hdr_size = sizeof(*unicast_packet);
 824         bool is4addr;
 825
 826         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 827         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 828
 829         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 830         /* the caller function should have already pulled 2 bytes */
 831         if (is4addr)
 832                 hdr_size = sizeof(*unicast_4addr_packet);
 833
 834         /* function returns -EREMOTE for promiscuous packets */
 835         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 836
 837         /* Even though the packet is not for us, we might save it to use for
 838          * decoding a later received coded packet
 839          */
 840         if (check == -EREMOTE)
 841                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 842
 843         if (check < 0)
 844                 return NET_RX_DROP;
 845         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 846                 return NET_RX_DROP;
 847
 848         /* packet for me */
 849         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 850                 if (is4addr) {
 851                         batadv_dat_inc_counter(bat_priv,
 852                                                unicast_4addr_packet->subtype);
 853                         orig_addr = unicast_4addr_packet->src;
 854                         orig_node = batadv_orig_hash_find(bat_priv, orig_addr);
 855                 }
 856
 857                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 858                                                           hdr_size))
 859                         goto rx_success;
 860                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 861                                                         hdr_size))
 862                         goto rx_success;
 863
 864                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
 865                                     orig_node);
 866
 867 rx_success:
 868                 if (orig_node)
 869                         batadv_orig_node_free_ref(orig_node);
 870
 871                 return NET_RX_SUCCESS;
 872         }
 873
 874         return batadv_route_unicast_packet(skb, recv_if);
 875 }
 876
 877 /**
 878  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
 879  * @skb: unicast tvlv packet to process
 880  * @recv_if: pointer to interface this packet was received on
 881  * @dst_addr: the payload destination
 882  *
 883  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 884  * otherwise.
 885  */
 886 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
 887                              struct batadv_hard_iface *recv_if)
 888 {
 889         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 890         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
 891         unsigned char *tvlv_buff;
 892         uint16_t tvlv_buff_len;
 893         int hdr_size = sizeof(*unicast_tvlv_packet);
 894         int ret = NET_RX_DROP;
 895
 896         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
 897                 return NET_RX_DROP;
 898
 899         /* the header is likely to be modified while forwarding */
 900         if (skb_cow(skb, hdr_size) < 0)
 901                 return NET_RX_DROP;
 902
 903         /* packet needs to be linearized to access the tvlv content */
 904         if (skb_linearize(skb) < 0)
 905                 return NET_RX_DROP;
 906
 907         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
 908
 909         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
 910         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
 911
 912         if (tvlv_buff_len > skb->len - hdr_size)
 913                 return NET_RX_DROP;
 914
 915         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
 916                                              unicast_tvlv_packet->src,
 917                                              unicast_tvlv_packet->dst,
 918                                              tvlv_buff, tvlv_buff_len);
 919
 920         if (ret != NET_RX_SUCCESS)
 921                 ret = batadv_route_unicast_packet(skb, recv_if);
 922         else
 923                 consume_skb(skb);
 924
 925         return ret;
 926 }
 927
 928 /**
 929  * batadv_recv_frag_packet - process received fragment
 930  * @skb: the received fragment
 931  * @recv_if: interface that the skb is received on
 932  *
 933  * This function does one of the three following things: 1) Forward fragment, if
 934  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
 935  * lack further fragments; 3) Merge fragments, if we have all needed parts.
 936  *
 937  * Return NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
 938  */
 939 int batadv_recv_frag_packet(struct sk_buff *skb,
 940                             struct batadv_hard_iface *recv_if)
 941 {
 942         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 943         struct batadv_orig_node *orig_node_src = NULL;
 944         struct batadv_frag_packet *frag_packet;
 945         int ret = NET_RX_DROP;
 946
 947         if (batadv_check_unicast_packet(bat_priv, skb,
 948                                         sizeof(*frag_packet)) < 0)
 949                 goto out;
 950
 951         frag_packet = (struct batadv_frag_packet *)skb->data;
 952         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
 953         if (!orig_node_src)
 954                 goto out;
 955
 956         /* Route the fragment if it is not for us and too big to be merged. */
 957         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
 958             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
 959                 ret = NET_RX_SUCCESS;
 960                 goto out;
 961         }
 962
 963         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
 964         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
 965
 966         /* Add fragment to buffer and merge if possible. */
 967         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
 968                 goto out;
 969
 970         /* Deliver merged packet to the appropriate handler, if it was
 971          * merged
 972          */
 973         if (skb)
 974                 batadv_batman_skb_recv(skb, recv_if->net_dev,
 975                                        &recv_if->batman_adv_ptype, NULL);
 976
 977         ret = NET_RX_SUCCESS;
 978
 979 out:
 980         if (orig_node_src)
 981                 batadv_orig_node_free_ref(orig_node_src);
 982
 983         return ret;
 984 }
 985
 986 int batadv_recv_bcast_packet(struct sk_buff *skb,
 987                              struct batadv_hard_iface *recv_if)
 988 {
 989         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 990         struct batadv_orig_node *orig_node = NULL;
 991         struct batadv_bcast_packet *bcast_packet;
 992         struct ethhdr *ethhdr;
 993         int hdr_size = sizeof(*bcast_packet);
 994         int ret = NET_RX_DROP;
 995         int32_t seq_diff;
 996         uint32_t seqno;
 997
 998         /* drop packet if it has not necessary minimum size */
 999         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1000                 goto out;
1001
1002         ethhdr = eth_hdr(skb);
1003
1004         /* packet with broadcast indication but unicast recipient */
1005         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1006                 goto out;
1007
1008         /* packet with broadcast sender address */
1009         if (is_broadcast_ether_addr(ethhdr->h_source))
1010                 goto out;
1011
1012         /* ignore broadcasts sent by myself */
1013         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1014                 goto out;
1015
1016         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1017
1018         /* ignore broadcasts originated by myself */
1019         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1020                 goto out;
1021
1022         if (bcast_packet->ttl < 2)
1023                 goto out;
1024
1025         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1026
1027         if (!orig_node)
1028                 goto out;
1029
1030         spin_lock_bh(&orig_node->bcast_seqno_lock);
1031
1032         seqno = ntohl(bcast_packet->seqno);
1033         /* check whether the packet is a duplicate */
1034         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1035                             seqno))
1036                 goto spin_unlock;
1037
1038         seq_diff = seqno - orig_node->last_bcast_seqno;
1039
1040         /* check whether the packet is old and the host just restarted. */
1041         if (batadv_window_protected(bat_priv, seq_diff,
1042                                     &orig_node->bcast_seqno_reset))
1043                 goto spin_unlock;
1044
1045         /* mark broadcast in flood history, update window position
1046          * if required.
1047          */
1048         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1049                 orig_node->last_bcast_seqno = seqno;
1050
1051         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1052
1053         /* check whether this has been sent by another originator before */
1054         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1055                 goto out;
1056
1057         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1058
1059         /* rebroadcast packet */
1060         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1061
1062         /* don't hand the broadcast up if it is from an originator
1063          * from the same backbone.
1064          */
1065         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1066                 goto out;
1067
1068         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1069                 goto rx_success;
1070         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1071                 goto rx_success;
1072
1073         /* broadcast for me */
1074         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1075                             orig_node);
1076
1077 rx_success:
1078         ret = NET_RX_SUCCESS;
1079         goto out;
1080
1081 spin_unlock:
1082         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1083 out:
1084         if (orig_node)
1085                 batadv_orig_node_free_ref(orig_node);
1086         return ret;
1087 }