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                 memcpy(icmph->dst, icmph->orig, ETH_ALEN);
 226                 memcpy(icmph->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 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         memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
 280         memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr,
 281                ETH_ALEN);
 282         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 283         icmp_packet->ttl = BATADV_TTL;
 284
 285         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 286                 ret = NET_RX_SUCCESS;
 287
 288 out:
 289         if (primary_if)
 290                 batadv_hardif_free_ref(primary_if);
 291         if (orig_node)
 292                 batadv_orig_node_free_ref(orig_node);
 293         return ret;
 294 }
 295
 296
 297 int batadv_recv_icmp_packet(struct sk_buff *skb,
 298                             struct batadv_hard_iface *recv_if)
 299 {
 300         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 301         struct batadv_icmp_header *icmph;
 302         struct batadv_icmp_packet_rr *icmp_packet_rr;
 303         struct ethhdr *ethhdr;
 304         struct batadv_orig_node *orig_node = NULL;
 305         int hdr_size = sizeof(struct batadv_icmp_header);
 306         int ret = NET_RX_DROP;
 307
 308         /* drop packet if it has not necessary minimum size */
 309         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 310                 goto out;
 311
 312         ethhdr = eth_hdr(skb);
 313
 314         /* packet with unicast indication but broadcast recipient */
 315         if (is_broadcast_ether_addr(ethhdr->h_dest))
 316                 goto out;
 317
 318         /* packet with broadcast sender address */
 319         if (is_broadcast_ether_addr(ethhdr->h_source))
 320                 goto out;
 321
 322         /* not for me */
 323         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 324                 goto out;
 325
 326         icmph = (struct batadv_icmp_header *)skb->data;
 327
 328         /* add record route information if not full */
 329         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 330              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 331             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 332                 if (skb_linearize(skb) < 0)
 333                         goto out;
 334
 335                 /* create a copy of the skb, if needed, to modify it. */
 336                 if (skb_cow(skb, ETH_HLEN) < 0)
 337                         goto out;
 338
 339                 icmph = (struct batadv_icmp_header *)skb->data;
 340                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 341                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 342                         goto out;
 343
 344                 memcpy(&(icmp_packet_rr->rr[icmp_packet_rr->rr_cur]),
 345                        ethhdr->h_dest, ETH_ALEN);
 346                 icmp_packet_rr->rr_cur++;
 347         }
 348
 349         /* packet for me */
 350         if (batadv_is_my_mac(bat_priv, icmph->dst))
 351                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 352
 353         /* TTL exceeded */
 354         if (icmph->ttl < 2)
 355                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 356
 357         /* get routing information */
 358         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 359         if (!orig_node)
 360                 goto out;
 361
 362         /* create a copy of the skb, if needed, to modify it. */
 363         if (skb_cow(skb, ETH_HLEN) < 0)
 364                 goto out;
 365
 366         icmph = (struct batadv_icmp_header *)skb->data;
 367
 368         /* decrement ttl */
 369         icmph->ttl--;
 370
 371         /* route it */
 372         if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
 373                 ret = NET_RX_SUCCESS;
 374
 375 out:
 376         if (orig_node)
 377                 batadv_orig_node_free_ref(orig_node);
 378         return ret;
 379 }
 380
 381 /**
 382  * batadv_check_unicast_packet - Check for malformed unicast packets
 383  * @bat_priv: the bat priv with all the soft interface information
 384  * @skb: packet to check
 385  * @hdr_size: size of header to pull
 386  *
 387  * Check for short header and bad addresses in given packet. Returns negative
 388  * value when check fails and 0 otherwise. The negative value depends on the
 389  * reason: -ENODATA for bad header, -EBADR for broadcast destination or source,
 390  * and -EREMOTE for non-local (other host) destination.
 391  */
 392 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 393                                        struct sk_buff *skb, int hdr_size)
 394 {
 395         struct ethhdr *ethhdr;
 396
 397         /* drop packet if it has not necessary minimum size */
 398         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 399                 return -ENODATA;
 400
 401         ethhdr = eth_hdr(skb);
 402
 403         /* packet with unicast indication but broadcast recipient */
 404         if (is_broadcast_ether_addr(ethhdr->h_dest))
 405                 return -EBADR;
 406
 407         /* packet with broadcast sender address */
 408         if (is_broadcast_ether_addr(ethhdr->h_source))
 409                 return -EBADR;
 410
 411         /* not for me */
 412         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 413                 return -EREMOTE;
 414
 415         return 0;
 416 }
 417
 418 /**
 419  * batadv_find_router - find a suitable router for this originator
 420  * @bat_priv: the bat priv with all the soft interface information
 421  * @orig_node: the destination node
 422  * @recv_if: pointer to interface this packet was received on
 423  *
 424  * Returns the router which should be used for this orig_node on
 425  * this interface, or NULL if not available.
 426  */
 427 struct batadv_neigh_node *
 428 batadv_find_router(struct batadv_priv *bat_priv,
 429                    struct batadv_orig_node *orig_node,
 430                    struct batadv_hard_iface *recv_if)
 431 {
 432         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 433         struct batadv_neigh_node *first_candidate_router = NULL;
 434         struct batadv_neigh_node *next_candidate_router = NULL;
 435         struct batadv_neigh_node *router, *cand_router = NULL;
 436         struct batadv_neigh_node *last_cand_router = NULL;
 437         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
 438         struct batadv_orig_ifinfo *next_candidate = NULL;
 439         struct batadv_orig_ifinfo *last_candidate;
 440         bool last_candidate_found = false;
 441
 442         if (!orig_node)
 443                 return NULL;
 444
 445         router = batadv_orig_router_get(orig_node, recv_if);
 446
 447         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 448          * and if activated.
 449          */
 450         if (recv_if == BATADV_IF_DEFAULT || !atomic_read(&bat_priv->bonding) ||
 451             !router)
 452                 return router;
 453
 454         /* bonding: loop through the list of possible routers found
 455          * for the various outgoing interfaces and find a candidate after
 456          * the last chosen bonding candidate (next_candidate). If no such
 457          * router is found, use the first candidate found (the previously
 458          * chosen bonding candidate might have been the last one in the list).
 459          * If this can't be found either, return the previously choosen
 460          * router - obviously there are no other candidates.
 461          */
 462         rcu_read_lock();
 463         last_candidate = orig_node->last_bonding_candidate;
 464         if (last_candidate)
 465                 last_cand_router = rcu_dereference(last_candidate->router);
 466
 467         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 468                 /* acquire some structures and references ... */
 469                 if (!atomic_inc_not_zero(&cand->refcount))
 470                         continue;
 471
 472                 cand_router = rcu_dereference(cand->router);
 473                 if (!cand_router)
 474                         goto next;
 475
 476                 if (!atomic_inc_not_zero(&cand_router->refcount)) {
 477                         cand_router = NULL;
 478                         goto next;
 479                 }
 480
 481                 /* alternative candidate should be good enough to be
 482                  * considered
 483                  */
 484                 if (!bao->bat_neigh_is_equiv_or_better(cand_router,
 485                                                        cand->if_outgoing,
 486                                                        router, recv_if))
 487                         goto next;
 488
 489                 /* don't use the same router twice */
 490                 if (last_cand_router == cand_router)
 491                         goto next;
 492
 493                 /* mark the first possible candidate */
 494                 if (!first_candidate) {
 495                         atomic_inc(&cand_router->refcount);
 496                         atomic_inc(&cand->refcount);
 497                         first_candidate = cand;
 498                         first_candidate_router = cand_router;
 499                 }
 500
 501                 /* check if the loop has already passed the previously selected
 502                  * candidate ... this function should select the next candidate
 503                  * AFTER the previously used bonding candidate.
 504                  */
 505                 if (!last_candidate || last_candidate_found) {
 506                         next_candidate = cand;
 507                         next_candidate_router = cand_router;
 508                         break;
 509                 }
 510
 511                 if (last_candidate == cand)
 512                         last_candidate_found = true;
 513 next:
 514                 /* free references */
 515                 if (cand_router) {
 516                         batadv_neigh_node_free_ref(cand_router);
 517                         cand_router = NULL;
 518                 }
 519                 batadv_orig_ifinfo_free_ref(cand);
 520         }
 521         rcu_read_unlock();
 522
 523         /* last_bonding_candidate is reset below, remove the old reference. */
 524         if (orig_node->last_bonding_candidate)
 525                 batadv_orig_ifinfo_free_ref(orig_node->last_bonding_candidate);
 526
 527         /* After finding candidates, handle the three cases:
 528          * 1) there is a next candidate, use that
 529          * 2) there is no next candidate, use the first of the list
 530          * 3) there is no candidate at all, return the default router
 531          */
 532         if (next_candidate) {
 533                 batadv_neigh_node_free_ref(router);
 534
 535                 /* remove references to first candidate, we don't need it. */
 536                 if (first_candidate) {
 537                         batadv_neigh_node_free_ref(first_candidate_router);
 538                         batadv_orig_ifinfo_free_ref(first_candidate);
 539                 }
 540                 router = next_candidate_router;
 541                 orig_node->last_bonding_candidate = next_candidate;
 542         } else if (first_candidate) {
 543                 batadv_neigh_node_free_ref(router);
 544
 545                 /* refcounting has already been done in the loop above. */
 546                 router = first_candidate_router;
 547                 orig_node->last_bonding_candidate = first_candidate;
 548         } else {
 549                 orig_node->last_bonding_candidate = NULL;
 550         }
 551
 552         return router;
 553 }
 554
 555 static int batadv_route_unicast_packet(struct sk_buff *skb,
 556                                        struct batadv_hard_iface *recv_if)
 557 {
 558         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 559         struct batadv_orig_node *orig_node = NULL;
 560         struct batadv_unicast_packet *unicast_packet;
 561         struct ethhdr *ethhdr = eth_hdr(skb);
 562         int res, hdr_len, ret = NET_RX_DROP;
 563
 564         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 565
 566         /* TTL exceeded */
 567         if (unicast_packet->ttl < 2) {
 568                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 569                          ethhdr->h_source, unicast_packet->dest);
 570                 goto out;
 571         }
 572
 573         /* get routing information */
 574         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 575
 576         if (!orig_node)
 577                 goto out;
 578
 579         /* create a copy of the skb, if needed, to modify it. */
 580         if (skb_cow(skb, ETH_HLEN) < 0)
 581                 goto out;
 582
 583         /* decrement ttl */
 584         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 585         unicast_packet->ttl--;
 586
 587         switch (unicast_packet->packet_type) {
 588         case BATADV_UNICAST_4ADDR:
 589                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 590                 break;
 591         case BATADV_UNICAST:
 592                 hdr_len = sizeof(struct batadv_unicast_packet);
 593                 break;
 594         default:
 595                 /* other packet types not supported - yet */
 596                 hdr_len = -1;
 597                 break;
 598         }
 599
 600         if (hdr_len > 0)
 601                 batadv_skb_set_priority(skb, hdr_len);
 602
 603         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 604
 605         /* translate transmit result into receive result */
 606         if (res == NET_XMIT_SUCCESS) {
 607                 /* skb was transmitted and consumed */
 608                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 609                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 610                                    skb->len + ETH_HLEN);
 611
 612                 ret = NET_RX_SUCCESS;
 613         } else if (res == NET_XMIT_POLICED) {
 614                 /* skb was buffered and consumed */
 615                 ret = NET_RX_SUCCESS;
 616         }
 617
 618 out:
 619         if (orig_node)
 620                 batadv_orig_node_free_ref(orig_node);
 621         return ret;
 622 }
 623
 624 /**
 625  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 626  * @bat_priv: the bat priv with all the soft interface information
 627  * @unicast_packet: the unicast header to be updated
 628  * @dst_addr: the payload destination
 629  * @vid: VLAN identifier
 630  *
 631  * Search the translation table for dst_addr and update the unicast header with
 632  * the new corresponding information (originator address where the destination
 633  * client currently is and its known TTVN)
 634  *
 635  * Returns true if the packet header has been updated, false otherwise
 636  */
 637 static bool
 638 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 639                               struct batadv_unicast_packet *unicast_packet,
 640                               uint8_t *dst_addr, unsigned short vid)
 641 {
 642         struct batadv_orig_node *orig_node = NULL;
 643         struct batadv_hard_iface *primary_if = NULL;
 644         bool ret = false;
 645         uint8_t *orig_addr, orig_ttvn;
 646
 647         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 648                 primary_if = batadv_primary_if_get_selected(bat_priv);
 649                 if (!primary_if)
 650                         goto out;
 651                 orig_addr = primary_if->net_dev->dev_addr;
 652                 orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 653         } else {
 654                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 655                                                      vid);
 656                 if (!orig_node)
 657                         goto out;
 658
 659                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 660                         goto out;
 661
 662                 orig_addr = orig_node->orig;
 663                 orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 664         }
 665
 666         /* update the packet header */
 667         memcpy(unicast_packet->dest, orig_addr, ETH_ALEN);
 668         unicast_packet->ttvn = orig_ttvn;
 669
 670         ret = true;
 671 out:
 672         if (primary_if)
 673                 batadv_hardif_free_ref(primary_if);
 674         if (orig_node)
 675                 batadv_orig_node_free_ref(orig_node);
 676
 677         return ret;
 678 }
 679
 680 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 681                                      struct sk_buff *skb, int hdr_len) {
 682         struct batadv_unicast_packet *unicast_packet;
 683         struct batadv_hard_iface *primary_if;
 684         struct batadv_orig_node *orig_node;
 685         uint8_t curr_ttvn, old_ttvn;
 686         struct ethhdr *ethhdr;
 687         unsigned short vid;
 688         int is_old_ttvn;
 689
 690         /* check if there is enough data before accessing it */
 691         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 692                 return 0;
 693
 694         /* create a copy of the skb (in case of for re-routing) to modify it. */
 695         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 696                 return 0;
 697
 698         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 699         vid = batadv_get_vid(skb, hdr_len);
 700         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 701
 702         /* check if the destination client was served by this node and it is now
 703          * roaming. In this case, it means that the node has got a ROAM_ADV
 704          * message and that it knows the new destination in the mesh to re-route
 705          * the packet to
 706          */
 707         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 708                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 709                                                   ethhdr->h_dest, vid))
 710                         net_ratelimited_function(batadv_dbg, BATADV_DBG_TT,
 711                                                  bat_priv,
 712                                                  "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 713                                                  unicast_packet->dest,
 714                                                  ethhdr->h_dest);
 715                 /* at this point the mesh destination should have been
 716                  * substituted with the originator address found in the global
 717                  * table. If not, let the packet go untouched anyway because
 718                  * there is nothing the node can do
 719                  */
 720                 return 1;
 721         }
 722
 723         /* retrieve the TTVN known by this node for the packet destination. This
 724          * value is used later to check if the node which sent (or re-routed
 725          * last time) the packet had an updated information or not
 726          */
 727         curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
 728         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 729                 orig_node = batadv_orig_hash_find(bat_priv,
 730                                                   unicast_packet->dest);
 731                 /* if it is not possible to find the orig_node representing the
 732                  * destination, the packet can immediately be dropped as it will
 733                  * not be possible to deliver it
 734                  */
 735                 if (!orig_node)
 736                         return 0;
 737
 738                 curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
 739                 batadv_orig_node_free_ref(orig_node);
 740         }
 741
 742         /* check if the TTVN contained in the packet is fresher than what the
 743          * node knows
 744          */
 745         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 746         if (!is_old_ttvn)
 747                 return 1;
 748
 749         old_ttvn = unicast_packet->ttvn;
 750         /* the packet was forged based on outdated network information. Its
 751          * destination can possibly be updated and forwarded towards the new
 752          * target host
 753          */
 754         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 755                                           ethhdr->h_dest, vid)) {
 756                 net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv,
 757                                          "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 758                                          unicast_packet->dest, ethhdr->h_dest,
 759                                          old_ttvn, curr_ttvn);
 760                 return 1;
 761         }
 762
 763         /* the packet has not been re-routed: either the destination is
 764          * currently served by this node or there is no destination at all and
 765          * it is possible to drop the packet
 766          */
 767         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 768                 return 0;
 769
 770         /* update the header in order to let the packet be delivered to this
 771          * node's soft interface
 772          */
 773         primary_if = batadv_primary_if_get_selected(bat_priv);
 774         if (!primary_if)
 775                 return 0;
 776
 777         memcpy(unicast_packet->dest, primary_if->net_dev->dev_addr, ETH_ALEN);
 778
 779         batadv_hardif_free_ref(primary_if);
 780
 781         unicast_packet->ttvn = curr_ttvn;
 782
 783         return 1;
 784 }
 785
 786 /**
 787  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 788  *      are in the unicast number space but not yet known to the implementation
 789  * @skb: unicast tvlv packet to process
 790  * @recv_if: pointer to interface this packet was received on
 791  *
 792  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 793  * otherwise.
 794  */
 795 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 796                                          struct batadv_hard_iface *recv_if)
 797 {
 798         struct batadv_unicast_packet *unicast_packet;
 799         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 800         int check, hdr_size = sizeof(*unicast_packet);
 801
 802         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 803         if (check < 0)
 804                 return NET_RX_DROP;
 805
 806         /* we don't know about this type, drop it. */
 807         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 808         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 809                 return NET_RX_DROP;
 810
 811         return batadv_route_unicast_packet(skb, recv_if);
 812 }
 813
 814 int batadv_recv_unicast_packet(struct sk_buff *skb,
 815                                struct batadv_hard_iface *recv_if)
 816 {
 817         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 818         struct batadv_unicast_packet *unicast_packet;
 819         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 820         uint8_t *orig_addr;
 821         struct batadv_orig_node *orig_node = NULL;
 822         int check, hdr_size = sizeof(*unicast_packet);
 823         bool is4addr;
 824
 825         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 826         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 827
 828         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 829         /* the caller function should have already pulled 2 bytes */
 830         if (is4addr)
 831                 hdr_size = sizeof(*unicast_4addr_packet);
 832
 833         /* function returns -EREMOTE for promiscuous packets */
 834         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 835
 836         /* Even though the packet is not for us, we might save it to use for
 837          * decoding a later received coded packet
 838          */
 839         if (check == -EREMOTE)
 840                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 841
 842         if (check < 0)
 843                 return NET_RX_DROP;
 844         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 845                 return NET_RX_DROP;
 846
 847         /* packet for me */
 848         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 849                 if (is4addr) {
 850                         batadv_dat_inc_counter(bat_priv,
 851                                                unicast_4addr_packet->subtype);
 852                         orig_addr = unicast_4addr_packet->src;
 853                         orig_node = batadv_orig_hash_find(bat_priv, orig_addr);
 854                 }
 855
 856                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 857                                                           hdr_size))
 858                         goto rx_success;
 859                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 860                                                         hdr_size))
 861                         goto rx_success;
 862
 863                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
 864                                     orig_node);
 865
 866 rx_success:
 867                 if (orig_node)
 868                         batadv_orig_node_free_ref(orig_node);
 869
 870                 return NET_RX_SUCCESS;
 871         }
 872
 873         return batadv_route_unicast_packet(skb, recv_if);
 874 }
 875
 876 /**
 877  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
 878  * @skb: unicast tvlv packet to process
 879  * @recv_if: pointer to interface this packet was received on
 880  * @dst_addr: the payload destination
 881  *
 882  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 883  * otherwise.
 884  */
 885 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
 886                              struct batadv_hard_iface *recv_if)
 887 {
 888         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 889         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
 890         unsigned char *tvlv_buff;
 891         uint16_t tvlv_buff_len;
 892         int hdr_size = sizeof(*unicast_tvlv_packet);
 893         int ret = NET_RX_DROP;
 894
 895         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
 896                 return NET_RX_DROP;
 897
 898         /* the header is likely to be modified while forwarding */
 899         if (skb_cow(skb, hdr_size) < 0)
 900                 return NET_RX_DROP;
 901
 902         /* packet needs to be linearized to access the tvlv content */
 903         if (skb_linearize(skb) < 0)
 904                 return NET_RX_DROP;
 905
 906         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
 907
 908         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
 909         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
 910
 911         if (tvlv_buff_len > skb->len - hdr_size)
 912                 return NET_RX_DROP;
 913
 914         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
 915                                              unicast_tvlv_packet->src,
 916                                              unicast_tvlv_packet->dst,
 917                                              tvlv_buff, tvlv_buff_len);
 918
 919         if (ret != NET_RX_SUCCESS)
 920                 ret = batadv_route_unicast_packet(skb, recv_if);
 921         else
 922                 consume_skb(skb);
 923
 924         return ret;
 925 }
 926
 927 /**
 928  * batadv_recv_frag_packet - process received fragment
 929  * @skb: the received fragment
 930  * @recv_if: interface that the skb is received on
 931  *
 932  * This function does one of the three following things: 1) Forward fragment, if
 933  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
 934  * lack further fragments; 3) Merge fragments, if we have all needed parts.
 935  *
 936  * Return NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
 937  */
 938 int batadv_recv_frag_packet(struct sk_buff *skb,
 939                             struct batadv_hard_iface *recv_if)
 940 {
 941         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 942         struct batadv_orig_node *orig_node_src = NULL;
 943         struct batadv_frag_packet *frag_packet;
 944         int ret = NET_RX_DROP;
 945
 946         if (batadv_check_unicast_packet(bat_priv, skb,
 947                                         sizeof(*frag_packet)) < 0)
 948                 goto out;
 949
 950         frag_packet = (struct batadv_frag_packet *)skb->data;
 951         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
 952         if (!orig_node_src)
 953                 goto out;
 954
 955         /* Route the fragment if it is not for us and too big to be merged. */
 956         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
 957             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
 958                 ret = NET_RX_SUCCESS;
 959                 goto out;
 960         }
 961
 962         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
 963         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
 964
 965         /* Add fragment to buffer and merge if possible. */
 966         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
 967                 goto out;
 968
 969         /* Deliver merged packet to the appropriate handler, if it was
 970          * merged
 971          */
 972         if (skb)
 973                 batadv_batman_skb_recv(skb, recv_if->net_dev,
 974                                        &recv_if->batman_adv_ptype, NULL);
 975
 976         ret = NET_RX_SUCCESS;
 977
 978 out:
 979         if (orig_node_src)
 980                 batadv_orig_node_free_ref(orig_node_src);
 981
 982         return ret;
 983 }
 984
 985 int batadv_recv_bcast_packet(struct sk_buff *skb,
 986                              struct batadv_hard_iface *recv_if)
 987 {
 988         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 989         struct batadv_orig_node *orig_node = NULL;
 990         struct batadv_bcast_packet *bcast_packet;
 991         struct ethhdr *ethhdr;
 992         int hdr_size = sizeof(*bcast_packet);
 993         int ret = NET_RX_DROP;
 994         int32_t seq_diff;
 995         uint32_t seqno;
 996
 997         /* drop packet if it has not necessary minimum size */
 998         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 999                 goto out;
1000
1001         ethhdr = eth_hdr(skb);
1002
1003         /* packet with broadcast indication but unicast recipient */
1004         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1005                 goto out;
1006
1007         /* packet with broadcast sender address */
1008         if (is_broadcast_ether_addr(ethhdr->h_source))
1009                 goto out;
1010
1011         /* ignore broadcasts sent by myself */
1012         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1013                 goto out;
1014
1015         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1016
1017         /* ignore broadcasts originated by myself */
1018         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1019                 goto out;
1020
1021         if (bcast_packet->ttl < 2)
1022                 goto out;
1023
1024         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1025
1026         if (!orig_node)
1027                 goto out;
1028
1029         spin_lock_bh(&orig_node->bcast_seqno_lock);
1030
1031         seqno = ntohl(bcast_packet->seqno);
1032         /* check whether the packet is a duplicate */
1033         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1034                             seqno))
1035                 goto spin_unlock;
1036
1037         seq_diff = seqno - orig_node->last_bcast_seqno;
1038
1039         /* check whether the packet is old and the host just restarted. */
1040         if (batadv_window_protected(bat_priv, seq_diff,
1041                                     &orig_node->bcast_seqno_reset))
1042                 goto spin_unlock;
1043
1044         /* mark broadcast in flood history, update window position
1045          * if required.
1046          */
1047         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1048                 orig_node->last_bcast_seqno = seqno;
1049
1050         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1051
1052         /* check whether this has been sent by another originator before */
1053         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1054                 goto out;
1055
1056         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1057
1058         /* rebroadcast packet */
1059         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1060
1061         /* don't hand the broadcast up if it is from an originator
1062          * from the same backbone.
1063          */
1064         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1065                 goto out;
1066
1067         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1068                 goto rx_success;
1069         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1070                 goto rx_success;
1071
1072         /* broadcast for me */
1073         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1074                             orig_node);
1075
1076 rx_success:
1077         ret = NET_RX_SUCCESS;
1078         goto out;
1079
1080 spin_unlock:
1081         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1082 out:
1083         if (orig_node)
1084                 batadv_orig_node_free_ref(orig_node);
1085         return ret;
1086 }