net/batman-adv/routing.c

   1 /* Copyright (C) 2007-2015 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 "routing.h"
  19 #include "main.h"
  20
  21 #include <linux/atomic.h>
  22 #include <linux/byteorder/generic.h>
  23 #include <linux/compiler.h>
  24 #include <linux/errno.h>
  25 #include <linux/etherdevice.h>
  26 #include <linux/if_ether.h>
  27 #include <linux/jiffies.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/printk.h>
  30 #include <linux/rculist.h>
  31 #include <linux/rcupdate.h>
  32 #include <linux/skbuff.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/stddef.h>
  35
  36 #include "bitarray.h"
  37 #include "bridge_loop_avoidance.h"
  38 #include "distributed-arp-table.h"
  39 #include "fragmentation.h"
  40 #include "hard-interface.h"
  41 #include "icmp_socket.h"
  42 #include "network-coding.h"
  43 #include "originator.h"
  44 #include "packet.h"
  45 #include "send.h"
  46 #include "soft-interface.h"
  47 #include "translation-table.h"
  48
  49 static int batadv_route_unicast_packet(struct sk_buff *skb,
  50                                        struct batadv_hard_iface *recv_if);
  51
  52 /**
  53  * _batadv_update_route - set the router for this originator
  54  * @bat_priv: the bat priv with all the soft interface information
  55  * @orig_node: orig node which is to be configured
  56  * @recv_if: the receive interface for which this route is set
  57  * @neigh_node: neighbor which should be the next router
  58  *
  59  * This function does not perform any error checks
  60  */
  61 static void _batadv_update_route(struct batadv_priv *bat_priv,
  62                                  struct batadv_orig_node *orig_node,
  63                                  struct batadv_hard_iface *recv_if,
  64                                  struct batadv_neigh_node *neigh_node)
  65 {
  66         struct batadv_orig_ifinfo *orig_ifinfo;
  67         struct batadv_neigh_node *curr_router;
  68
  69         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
  70         if (!orig_ifinfo)
  71                 return;
  72
  73         rcu_read_lock();
  74         curr_router = rcu_dereference(orig_ifinfo->router);
  75         if (curr_router && !atomic_inc_not_zero(&curr_router->refcount))
  76                 curr_router = NULL;
  77         rcu_read_unlock();
  78
  79         /* route deleted */
  80         if ((curr_router) && (!neigh_node)) {
  81                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  82                            "Deleting route towards: %pM\n", orig_node->orig);
  83                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
  84                                           "Deleted route towards originator");
  85
  86         /* route added */
  87         } else if ((!curr_router) && (neigh_node)) {
  88                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  89                            "Adding route towards: %pM (via %pM)\n",
  90                            orig_node->orig, neigh_node->addr);
  91         /* route changed */
  92         } else if (neigh_node && curr_router) {
  93                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  94                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
  95                            orig_node->orig, neigh_node->addr,
  96                            curr_router->addr);
  97         }
  98
  99         if (curr_router)
 100                 batadv_neigh_node_free_ref(curr_router);
 101
 102         /* increase refcount of new best neighbor */
 103         if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
 104                 neigh_node = NULL;
 105
 106         spin_lock_bh(&orig_node->neigh_list_lock);
 107         /* curr_router used earlier may not be the current orig_ifinfo->router
 108          * anymore because it was dereferenced outside of the neigh_list_lock
 109          * protected region. After the new best neighbor has replace the current
 110          * best neighbor the reference counter needs to decrease. Consequently,
 111          * the code needs to ensure the curr_router variable contains a pointer
 112          * to the replaced best neighbor.
 113          */
 114         curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
 115
 116         rcu_assign_pointer(orig_ifinfo->router, neigh_node);
 117         spin_unlock_bh(&orig_node->neigh_list_lock);
 118         batadv_orig_ifinfo_free_ref(orig_ifinfo);
 119
 120         /* decrease refcount of previous best neighbor */
 121         if (curr_router)
 122                 batadv_neigh_node_free_ref(curr_router);
 123 }
 124
 125 /**
 126  * batadv_update_route - set the router for this originator
 127  * @bat_priv: the bat priv with all the soft interface information
 128  * @orig_node: orig node which is to be configured
 129  * @recv_if: the receive interface for which this route is set
 130  * @neigh_node: neighbor which should be the next router
 131  */
 132 void batadv_update_route(struct batadv_priv *bat_priv,
 133                          struct batadv_orig_node *orig_node,
 134                          struct batadv_hard_iface *recv_if,
 135                          struct batadv_neigh_node *neigh_node)
 136 {
 137         struct batadv_neigh_node *router = NULL;
 138
 139         if (!orig_node)
 140                 goto out;
 141
 142         router = batadv_orig_router_get(orig_node, recv_if);
 143
 144         if (router != neigh_node)
 145                 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
 146
 147 out:
 148         if (router)
 149                 batadv_neigh_node_free_ref(router);
 150 }
 151
 152 /* checks whether the host restarted and is in the protection time.
 153  * returns:
 154  *  0 if the packet is to be accepted
 155  *  1 if the packet is to be ignored.
 156  */
 157 int batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
 158                             unsigned long *last_reset)
 159 {
 160         if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
 161             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 162                 if (!batadv_has_timed_out(*last_reset,
 163                                           BATADV_RESET_PROTECTION_MS))
 164                         return 1;
 165
 166                 *last_reset = jiffies;
 167                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 168                            "old packet received, start protection\n");
 169         }
 170
 171         return 0;
 172 }
 173
 174 bool batadv_check_management_packet(struct sk_buff *skb,
 175                                     struct batadv_hard_iface *hard_iface,
 176                                     int header_len)
 177 {
 178         struct ethhdr *ethhdr;
 179
 180         /* drop packet if it has not necessary minimum size */
 181         if (unlikely(!pskb_may_pull(skb, header_len)))
 182                 return false;
 183
 184         ethhdr = eth_hdr(skb);
 185
 186         /* packet with broadcast indication but unicast recipient */
 187         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 188                 return false;
 189
 190         /* packet with broadcast sender address */
 191         if (is_broadcast_ether_addr(ethhdr->h_source))
 192                 return false;
 193
 194         /* create a copy of the skb, if needed, to modify it. */
 195         if (skb_cow(skb, 0) < 0)
 196                 return false;
 197
 198         /* keep skb linear */
 199         if (skb_linearize(skb) < 0)
 200                 return false;
 201
 202         return true;
 203 }
 204
 205 /**
 206  * batadv_recv_my_icmp_packet - receive an icmp packet locally
 207  * @bat_priv: the bat priv with all the soft interface information
 208  * @skb: icmp packet to process
 209  *
 210  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 211  * otherwise.
 212  */
 213 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 214                                       struct sk_buff *skb)
 215 {
 216         struct batadv_hard_iface *primary_if = NULL;
 217         struct batadv_orig_node *orig_node = NULL;
 218         struct batadv_icmp_header *icmph;
 219         int res, ret = NET_RX_DROP;
 220
 221         icmph = (struct batadv_icmp_header *)skb->data;
 222
 223         switch (icmph->msg_type) {
 224         case BATADV_ECHO_REPLY:
 225         case BATADV_DESTINATION_UNREACHABLE:
 226         case BATADV_TTL_EXCEEDED:
 227                 /* receive the packet */
 228                 if (skb_linearize(skb) < 0)
 229                         break;
 230
 231                 batadv_socket_receive_packet(icmph, skb->len);
 232                 break;
 233         case BATADV_ECHO_REQUEST:
 234                 /* answer echo request (ping) */
 235                 primary_if = batadv_primary_if_get_selected(bat_priv);
 236                 if (!primary_if)
 237                         goto out;
 238
 239                 /* get routing information */
 240                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 241                 if (!orig_node)
 242                         goto out;
 243
 244                 /* create a copy of the skb, if needed, to modify it. */
 245                 if (skb_cow(skb, ETH_HLEN) < 0)
 246                         goto out;
 247
 248                 icmph = (struct batadv_icmp_header *)skb->data;
 249
 250                 ether_addr_copy(icmph->dst, icmph->orig);
 251                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
 252                 icmph->msg_type = BATADV_ECHO_REPLY;
 253                 icmph->ttl = BATADV_TTL;
 254
 255                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 256                 if (res != NET_XMIT_DROP)
 257                         ret = NET_RX_SUCCESS;
 258
 259                 break;
 260         default:
 261                 /* drop unknown type */
 262                 goto out;
 263         }
 264 out:
 265         if (primary_if)
 266                 batadv_hardif_free_ref(primary_if);
 267         if (orig_node)
 268                 batadv_orig_node_free_ref(orig_node);
 269         return ret;
 270 }
 271
 272 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 273                                          struct sk_buff *skb)
 274 {
 275         struct batadv_hard_iface *primary_if = NULL;
 276         struct batadv_orig_node *orig_node = NULL;
 277         struct batadv_icmp_packet *icmp_packet;
 278         int ret = NET_RX_DROP;
 279
 280         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 281
 282         /* send TTL exceeded if packet is an echo request (traceroute) */
 283         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 284                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 285                          icmp_packet->orig, icmp_packet->dst);
 286                 goto out;
 287         }
 288
 289         primary_if = batadv_primary_if_get_selected(bat_priv);
 290         if (!primary_if)
 291                 goto out;
 292
 293         /* get routing information */
 294         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 295         if (!orig_node)
 296                 goto out;
 297
 298         /* create a copy of the skb, if needed, to modify it. */
 299         if (skb_cow(skb, ETH_HLEN) < 0)
 300                 goto out;
 301
 302         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 303
 304         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
 305         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
 306         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 307         icmp_packet->ttl = BATADV_TTL;
 308
 309         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 310                 ret = NET_RX_SUCCESS;
 311
 312 out:
 313         if (primary_if)
 314                 batadv_hardif_free_ref(primary_if);
 315         if (orig_node)
 316                 batadv_orig_node_free_ref(orig_node);
 317         return ret;
 318 }
 319
 320 int batadv_recv_icmp_packet(struct sk_buff *skb,
 321                             struct batadv_hard_iface *recv_if)
 322 {
 323         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 324         struct batadv_icmp_header *icmph;
 325         struct batadv_icmp_packet_rr *icmp_packet_rr;
 326         struct ethhdr *ethhdr;
 327         struct batadv_orig_node *orig_node = NULL;
 328         int hdr_size = sizeof(struct batadv_icmp_header);
 329         int ret = NET_RX_DROP;
 330
 331         /* drop packet if it has not necessary minimum size */
 332         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 333                 goto out;
 334
 335         ethhdr = eth_hdr(skb);
 336
 337         /* packet with unicast indication but broadcast recipient */
 338         if (is_broadcast_ether_addr(ethhdr->h_dest))
 339                 goto out;
 340
 341         /* packet with broadcast sender address */
 342         if (is_broadcast_ether_addr(ethhdr->h_source))
 343                 goto out;
 344
 345         /* not for me */
 346         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 347                 goto out;
 348
 349         icmph = (struct batadv_icmp_header *)skb->data;
 350
 351         /* add record route information if not full */
 352         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 353              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 354             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 355                 if (skb_linearize(skb) < 0)
 356                         goto out;
 357
 358                 /* create a copy of the skb, if needed, to modify it. */
 359                 if (skb_cow(skb, ETH_HLEN) < 0)
 360                         goto out;
 361
 362                 ethhdr = eth_hdr(skb);
 363                 icmph = (struct batadv_icmp_header *)skb->data;
 364                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 365                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 366                         goto out;
 367
 368                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
 369                                 ethhdr->h_dest);
 370                 icmp_packet_rr->rr_cur++;
 371         }
 372
 373         /* packet for me */
 374         if (batadv_is_my_mac(bat_priv, icmph->dst))
 375                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 376
 377         /* TTL exceeded */
 378         if (icmph->ttl < 2)
 379                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 380
 381         /* get routing information */
 382         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 383         if (!orig_node)
 384                 goto out;
 385
 386         /* create a copy of the skb, if needed, to modify it. */
 387         if (skb_cow(skb, ETH_HLEN) < 0)
 388                 goto out;
 389
 390         icmph = (struct batadv_icmp_header *)skb->data;
 391
 392         /* decrement ttl */
 393         icmph->ttl--;
 394
 395         /* route it */
 396         if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
 397                 ret = NET_RX_SUCCESS;
 398
 399 out:
 400         if (orig_node)
 401                 batadv_orig_node_free_ref(orig_node);
 402         return ret;
 403 }
 404
 405 /**
 406  * batadv_check_unicast_packet - Check for malformed unicast packets
 407  * @bat_priv: the bat priv with all the soft interface information
 408  * @skb: packet to check
 409  * @hdr_size: size of header to pull
 410  *
 411  * Check for short header and bad addresses in given packet. Returns negative
 412  * value when check fails and 0 otherwise. The negative value depends on the
 413  * reason: -ENODATA for bad header, -EBADR for broadcast destination or source,
 414  * and -EREMOTE for non-local (other host) destination.
 415  */
 416 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 417                                        struct sk_buff *skb, int hdr_size)
 418 {
 419         struct ethhdr *ethhdr;
 420
 421         /* drop packet if it has not necessary minimum size */
 422         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 423                 return -ENODATA;
 424
 425         ethhdr = eth_hdr(skb);
 426
 427         /* packet with unicast indication but broadcast recipient */
 428         if (is_broadcast_ether_addr(ethhdr->h_dest))
 429                 return -EBADR;
 430
 431         /* packet with broadcast sender address */
 432         if (is_broadcast_ether_addr(ethhdr->h_source))
 433                 return -EBADR;
 434
 435         /* not for me */
 436         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 437                 return -EREMOTE;
 438
 439         return 0;
 440 }
 441
 442 /**
 443  * batadv_last_bonding_get - Get last_bonding_candidate of orig_node
 444  * @orig_node: originator node whose last bonding candidate should be retrieved
 445  *
 446  * Return: last bonding candidate of router or NULL if not found
 447  *
 448  * The object is returned with refcounter increased by 1.
 449  */
 450 static struct batadv_orig_ifinfo *
 451 batadv_last_bonding_get(struct batadv_orig_node *orig_node)
 452 {
 453         struct batadv_orig_ifinfo *last_bonding_candidate;
 454
 455         spin_lock_bh(&orig_node->neigh_list_lock);
 456         last_bonding_candidate = orig_node->last_bonding_candidate;
 457
 458         if (last_bonding_candidate)
 459                 atomic_inc(&last_bonding_candidate->refcount);
 460         spin_unlock_bh(&orig_node->neigh_list_lock);
 461
 462         return last_bonding_candidate;
 463 }
 464
 465 /**
 466  * batadv_last_bonding_replace - Replace last_bonding_candidate of orig_node
 467  * @orig_node: originator node whose bonding candidates should be replaced
 468  * @new_candidate: new bonding candidate or NULL
 469  */
 470 static void
 471 batadv_last_bonding_replace(struct batadv_orig_node *orig_node,
 472                             struct batadv_orig_ifinfo *new_candidate)
 473 {
 474         struct batadv_orig_ifinfo *old_candidate;
 475
 476         spin_lock_bh(&orig_node->neigh_list_lock);
 477         old_candidate = orig_node->last_bonding_candidate;
 478
 479         if (new_candidate)
 480                 atomic_inc(&new_candidate->refcount);
 481         orig_node->last_bonding_candidate = new_candidate;
 482         spin_unlock_bh(&orig_node->neigh_list_lock);
 483
 484         if (old_candidate)
 485                 batadv_orig_ifinfo_free_ref(old_candidate);
 486 }
 487
 488 /**
 489  * batadv_find_router - find a suitable router for this originator
 490  * @bat_priv: the bat priv with all the soft interface information
 491  * @orig_node: the destination node
 492  * @recv_if: pointer to interface this packet was received on
 493  *
 494  * Returns the router which should be used for this orig_node on
 495  * this interface, or NULL if not available.
 496  */
 497 struct batadv_neigh_node *
 498 batadv_find_router(struct batadv_priv *bat_priv,
 499                    struct batadv_orig_node *orig_node,
 500                    struct batadv_hard_iface *recv_if)
 501 {
 502         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 503         struct batadv_neigh_node *first_candidate_router = NULL;
 504         struct batadv_neigh_node *next_candidate_router = NULL;
 505         struct batadv_neigh_node *router, *cand_router = NULL;
 506         struct batadv_neigh_node *last_cand_router = NULL;
 507         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
 508         struct batadv_orig_ifinfo *next_candidate = NULL;
 509         struct batadv_orig_ifinfo *last_candidate;
 510         bool last_candidate_found = false;
 511
 512         if (!orig_node)
 513                 return NULL;
 514
 515         router = batadv_orig_router_get(orig_node, recv_if);
 516
 517         if (!router)
 518                 return router;
 519
 520         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 521          * and if activated.
 522          */
 523         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
 524                 return router;
 525
 526         /* bonding: loop through the list of possible routers found
 527          * for the various outgoing interfaces and find a candidate after
 528          * the last chosen bonding candidate (next_candidate). If no such
 529          * router is found, use the first candidate found (the previously
 530          * chosen bonding candidate might have been the last one in the list).
 531          * If this can't be found either, return the previously chosen
 532          * router - obviously there are no other candidates.
 533          */
 534         rcu_read_lock();
 535         last_candidate = batadv_last_bonding_get(orig_node);
 536         if (last_candidate)
 537                 last_cand_router = rcu_dereference(last_candidate->router);
 538
 539         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 540                 /* acquire some structures and references ... */
 541                 if (!atomic_inc_not_zero(&cand->refcount))
 542                         continue;
 543
 544                 cand_router = rcu_dereference(cand->router);
 545                 if (!cand_router)
 546                         goto next;
 547
 548                 if (!atomic_inc_not_zero(&cand_router->refcount)) {
 549                         cand_router = NULL;
 550                         goto next;
 551                 }
 552
 553                 /* alternative candidate should be good enough to be
 554                  * considered
 555                  */
 556                 if (!bao->bat_neigh_is_equiv_or_better(cand_router,
 557                                                        cand->if_outgoing,
 558                                                        router, recv_if))
 559                         goto next;
 560
 561                 /* don't use the same router twice */
 562                 if (last_cand_router == cand_router)
 563                         goto next;
 564
 565                 /* mark the first possible candidate */
 566                 if (!first_candidate) {
 567                         atomic_inc(&cand_router->refcount);
 568                         atomic_inc(&cand->refcount);
 569                         first_candidate = cand;
 570                         first_candidate_router = cand_router;
 571                 }
 572
 573                 /* check if the loop has already passed the previously selected
 574                  * candidate ... this function should select the next candidate
 575                  * AFTER the previously used bonding candidate.
 576                  */
 577                 if (!last_candidate || last_candidate_found) {
 578                         next_candidate = cand;
 579                         next_candidate_router = cand_router;
 580                         break;
 581                 }
 582
 583                 if (last_candidate == cand)
 584                         last_candidate_found = true;
 585 next:
 586                 /* free references */
 587                 if (cand_router) {
 588                         batadv_neigh_node_free_ref(cand_router);
 589                         cand_router = NULL;
 590                 }
 591                 batadv_orig_ifinfo_free_ref(cand);
 592         }
 593         rcu_read_unlock();
 594
 595         /* After finding candidates, handle the three cases:
 596          * 1) there is a next candidate, use that
 597          * 2) there is no next candidate, use the first of the list
 598          * 3) there is no candidate at all, return the default router
 599          */
 600         if (next_candidate) {
 601                 batadv_neigh_node_free_ref(router);
 602
 603                 atomic_inc(&next_candidate_router->refcount);
 604                 router = next_candidate_router;
 605                 batadv_last_bonding_replace(orig_node, next_candidate);
 606         } else if (first_candidate) {
 607                 batadv_neigh_node_free_ref(router);
 608
 609                 atomic_inc(&first_candidate_router->refcount);
 610                 router = first_candidate_router;
 611                 batadv_last_bonding_replace(orig_node, first_candidate);
 612         } else {
 613                 batadv_last_bonding_replace(orig_node, NULL);
 614         }
 615
 616         /* cleanup of candidates */
 617         if (first_candidate) {
 618                 batadv_neigh_node_free_ref(first_candidate_router);
 619                 batadv_orig_ifinfo_free_ref(first_candidate);
 620         }
 621
 622         if (next_candidate) {
 623                 batadv_neigh_node_free_ref(next_candidate_router);
 624                 batadv_orig_ifinfo_free_ref(next_candidate);
 625         }
 626
 627         if (last_candidate)
 628                 batadv_orig_ifinfo_free_ref(last_candidate);
 629
 630         return router;
 631 }
 632
 633 static int batadv_route_unicast_packet(struct sk_buff *skb,
 634                                        struct batadv_hard_iface *recv_if)
 635 {
 636         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 637         struct batadv_orig_node *orig_node = NULL;
 638         struct batadv_unicast_packet *unicast_packet;
 639         struct ethhdr *ethhdr = eth_hdr(skb);
 640         int res, hdr_len, ret = NET_RX_DROP;
 641         unsigned int len;
 642
 643         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 644
 645         /* TTL exceeded */
 646         if (unicast_packet->ttl < 2) {
 647                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 648                          ethhdr->h_source, unicast_packet->dest);
 649                 goto out;
 650         }
 651
 652         /* get routing information */
 653         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 654
 655         if (!orig_node)
 656                 goto out;
 657
 658         /* create a copy of the skb, if needed, to modify it. */
 659         if (skb_cow(skb, ETH_HLEN) < 0)
 660                 goto out;
 661
 662         /* decrement ttl */
 663         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 664         unicast_packet->ttl--;
 665
 666         switch (unicast_packet->packet_type) {
 667         case BATADV_UNICAST_4ADDR:
 668                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 669                 break;
 670         case BATADV_UNICAST:
 671                 hdr_len = sizeof(struct batadv_unicast_packet);
 672                 break;
 673         default:
 674                 /* other packet types not supported - yet */
 675                 hdr_len = -1;
 676                 break;
 677         }
 678
 679         if (hdr_len > 0)
 680                 batadv_skb_set_priority(skb, hdr_len);
 681
 682         len = skb->len;
 683         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 684
 685         /* translate transmit result into receive result */
 686         if (res == NET_XMIT_SUCCESS) {
 687                 /* skb was transmitted and consumed */
 688                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 689                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 690                                    len + ETH_HLEN);
 691
 692                 ret = NET_RX_SUCCESS;
 693         } else if (res == NET_XMIT_POLICED) {
 694                 /* skb was buffered and consumed */
 695                 ret = NET_RX_SUCCESS;
 696         }
 697
 698 out:
 699         if (orig_node)
 700                 batadv_orig_node_free_ref(orig_node);
 701         return ret;
 702 }
 703
 704 /**
 705  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 706  * @bat_priv: the bat priv with all the soft interface information
 707  * @skb: unicast packet to process
 708  * @unicast_packet: the unicast header to be updated
 709  * @dst_addr: the payload destination
 710  * @vid: VLAN identifier
 711  *
 712  * Search the translation table for dst_addr and update the unicast header with
 713  * the new corresponding information (originator address where the destination
 714  * client currently is and its known TTVN)
 715  *
 716  * Returns true if the packet header has been updated, false otherwise
 717  */
 718 static bool
 719 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
 720                               struct batadv_unicast_packet *unicast_packet,
 721                               u8 *dst_addr, unsigned short vid)
 722 {
 723         struct batadv_orig_node *orig_node = NULL;
 724         struct batadv_hard_iface *primary_if = NULL;
 725         bool ret = false;
 726         u8 *orig_addr, orig_ttvn;
 727
 728         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 729                 primary_if = batadv_primary_if_get_selected(bat_priv);
 730                 if (!primary_if)
 731                         goto out;
 732                 orig_addr = primary_if->net_dev->dev_addr;
 733                 orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 734         } else {
 735                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 736                                                      vid);
 737                 if (!orig_node)
 738                         goto out;
 739
 740                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 741                         goto out;
 742
 743                 orig_addr = orig_node->orig;
 744                 orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 745         }
 746
 747         /* update the packet header */
 748         skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
 749         ether_addr_copy(unicast_packet->dest, orig_addr);
 750         unicast_packet->ttvn = orig_ttvn;
 751         skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
 752
 753         ret = true;
 754 out:
 755         if (primary_if)
 756                 batadv_hardif_free_ref(primary_if);
 757         if (orig_node)
 758                 batadv_orig_node_free_ref(orig_node);
 759
 760         return ret;
 761 }
 762
 763 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 764                                      struct sk_buff *skb, int hdr_len) {
 765         struct batadv_unicast_packet *unicast_packet;
 766         struct batadv_hard_iface *primary_if;
 767         struct batadv_orig_node *orig_node;
 768         u8 curr_ttvn, old_ttvn;
 769         struct ethhdr *ethhdr;
 770         unsigned short vid;
 771         int is_old_ttvn;
 772
 773         /* check if there is enough data before accessing it */
 774         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 775                 return 0;
 776
 777         /* create a copy of the skb (in case of for re-routing) to modify it. */
 778         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 779                 return 0;
 780
 781         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 782         vid = batadv_get_vid(skb, hdr_len);
 783         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 784
 785         /* do not reroute multicast frames in a unicast header */
 786         if (is_multicast_ether_addr(ethhdr->h_dest))
 787                 return true;
 788
 789         /* check if the destination client was served by this node and it is now
 790          * roaming. In this case, it means that the node has got a ROAM_ADV
 791          * message and that it knows the new destination in the mesh to re-route
 792          * the packet to
 793          */
 794         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 795                 if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
 796                                                   ethhdr->h_dest, vid))
 797                         batadv_dbg_ratelimited(BATADV_DBG_TT,
 798                                                bat_priv,
 799                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 800                                                unicast_packet->dest,
 801                                                ethhdr->h_dest);
 802                 /* at this point the mesh destination should have been
 803                  * substituted with the originator address found in the global
 804                  * table. If not, let the packet go untouched anyway because
 805                  * there is nothing the node can do
 806                  */
 807                 return 1;
 808         }
 809
 810         /* retrieve the TTVN known by this node for the packet destination. This
 811          * value is used later to check if the node which sent (or re-routed
 812          * last time) the packet had an updated information or not
 813          */
 814         curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 815         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 816                 orig_node = batadv_orig_hash_find(bat_priv,
 817                                                   unicast_packet->dest);
 818                 /* if it is not possible to find the orig_node representing the
 819                  * destination, the packet can immediately be dropped as it will
 820                  * not be possible to deliver it
 821                  */
 822                 if (!orig_node)
 823                         return 0;
 824
 825                 curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 826                 batadv_orig_node_free_ref(orig_node);
 827         }
 828
 829         /* check if the TTVN contained in the packet is fresher than what the
 830          * node knows
 831          */
 832         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 833         if (!is_old_ttvn)
 834                 return 1;
 835
 836         old_ttvn = unicast_packet->ttvn;
 837         /* the packet was forged based on outdated network information. Its
 838          * destination can possibly be updated and forwarded towards the new
 839          * target host
 840          */
 841         if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
 842                                           ethhdr->h_dest, vid)) {
 843                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
 844                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 845                                        unicast_packet->dest, ethhdr->h_dest,
 846                                        old_ttvn, curr_ttvn);
 847                 return 1;
 848         }
 849
 850         /* the packet has not been re-routed: either the destination is
 851          * currently served by this node or there is no destination at all and
 852          * it is possible to drop the packet
 853          */
 854         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 855                 return 0;
 856
 857         /* update the header in order to let the packet be delivered to this
 858          * node's soft interface
 859          */
 860         primary_if = batadv_primary_if_get_selected(bat_priv);
 861         if (!primary_if)
 862                 return 0;
 863
 864         /* update the packet header */
 865         skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
 866         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
 867         unicast_packet->ttvn = curr_ttvn;
 868         skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
 869
 870         batadv_hardif_free_ref(primary_if);
 871
 872         return 1;
 873 }
 874
 875 /**
 876  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 877  *      are in the unicast number space but not yet known to the implementation
 878  * @skb: unicast tvlv packet to process
 879  * @recv_if: pointer to interface this packet was received on
 880  *
 881  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 882  * otherwise.
 883  */
 884 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 885                                          struct batadv_hard_iface *recv_if)
 886 {
 887         struct batadv_unicast_packet *unicast_packet;
 888         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 889         int check, hdr_size = sizeof(*unicast_packet);
 890
 891         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 892         if (check < 0)
 893                 return NET_RX_DROP;
 894
 895         /* we don't know about this type, drop it. */
 896         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 897         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 898                 return NET_RX_DROP;
 899
 900         return batadv_route_unicast_packet(skb, recv_if);
 901 }
 902
 903 int batadv_recv_unicast_packet(struct sk_buff *skb,
 904                                struct batadv_hard_iface *recv_if)
 905 {
 906         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 907         struct batadv_unicast_packet *unicast_packet;
 908         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 909         u8 *orig_addr;
 910         struct batadv_orig_node *orig_node = NULL;
 911         int check, hdr_size = sizeof(*unicast_packet);
 912         enum batadv_subtype subtype;
 913         bool is4addr;
 914
 915         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 916
 917         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 918         /* the caller function should have already pulled 2 bytes */
 919         if (is4addr)
 920                 hdr_size = sizeof(*unicast_4addr_packet);
 921
 922         /* function returns -EREMOTE for promiscuous packets */
 923         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 924
 925         /* Even though the packet is not for us, we might save it to use for
 926          * decoding a later received coded packet
 927          */
 928         if (check == -EREMOTE)
 929                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 930
 931         if (check < 0)
 932                 return NET_RX_DROP;
 933         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 934                 return NET_RX_DROP;
 935
 936         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 937
 938         /* packet for me */
 939         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 940                 if (is4addr) {
 941                         unicast_4addr_packet =
 942                                 (struct batadv_unicast_4addr_packet *)skb->data;
 943                         subtype = unicast_4addr_packet->subtype;
 944                         batadv_dat_inc_counter(bat_priv, subtype);
 945
 946                         /* Only payload data should be considered for speedy
 947                          * join. For example, DAT also uses unicast 4addr
 948                          * types, but those packets should not be considered
 949                          * for speedy join, since the clients do not actually
 950                          * reside at the sending originator.
 951                          */
 952                         if (subtype == BATADV_P_DATA) {
 953                                 orig_addr = unicast_4addr_packet->src;
 954                                 orig_node = batadv_orig_hash_find(bat_priv,
 955                                                                   orig_addr);
 956                         }
 957                 }
 958
 959                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 960                                                           hdr_size))
 961                         goto rx_success;
 962                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 963                                                         hdr_size))
 964                         goto rx_success;
 965
 966                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
 967                                     orig_node);
 968
 969 rx_success:
 970                 if (orig_node)
 971                         batadv_orig_node_free_ref(orig_node);
 972
 973                 return NET_RX_SUCCESS;
 974         }
 975
 976         return batadv_route_unicast_packet(skb, recv_if);
 977 }
 978
 979 /**
 980  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
 981  * @skb: unicast tvlv packet to process
 982  * @recv_if: pointer to interface this packet was received on
 983  * @dst_addr: the payload destination
 984  *
 985  * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 986  * otherwise.
 987  */
 988 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
 989                              struct batadv_hard_iface *recv_if)
 990 {
 991         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 992         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
 993         unsigned char *tvlv_buff;
 994         u16 tvlv_buff_len;
 995         int hdr_size = sizeof(*unicast_tvlv_packet);
 996         int ret = NET_RX_DROP;
 997
 998         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
 999                 return NET_RX_DROP;
1000
1001         /* the header is likely to be modified while forwarding */
1002         if (skb_cow(skb, hdr_size) < 0)
1003                 return NET_RX_DROP;
1004
1005         /* packet needs to be linearized to access the tvlv content */
1006         if (skb_linearize(skb) < 0)
1007                 return NET_RX_DROP;
1008
1009         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
1010
1011         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1012         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
1013
1014         if (tvlv_buff_len > skb->len - hdr_size)
1015                 return NET_RX_DROP;
1016
1017         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
1018                                              unicast_tvlv_packet->src,
1019                                              unicast_tvlv_packet->dst,
1020                                              tvlv_buff, tvlv_buff_len);
1021
1022         if (ret != NET_RX_SUCCESS)
1023                 ret = batadv_route_unicast_packet(skb, recv_if);
1024         else
1025                 consume_skb(skb);
1026
1027         return ret;
1028 }
1029
1030 /**
1031  * batadv_recv_frag_packet - process received fragment
1032  * @skb: the received fragment
1033  * @recv_if: interface that the skb is received on
1034  *
1035  * This function does one of the three following things: 1) Forward fragment, if
1036  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
1037  * lack further fragments; 3) Merge fragments, if we have all needed parts.
1038  *
1039  * Return NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1040  */
1041 int batadv_recv_frag_packet(struct sk_buff *skb,
1042                             struct batadv_hard_iface *recv_if)
1043 {
1044         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1045         struct batadv_orig_node *orig_node_src = NULL;
1046         struct batadv_frag_packet *frag_packet;
1047         int ret = NET_RX_DROP;
1048
1049         if (batadv_check_unicast_packet(bat_priv, skb,
1050                                         sizeof(*frag_packet)) < 0)
1051                 goto out;
1052
1053         frag_packet = (struct batadv_frag_packet *)skb->data;
1054         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1055         if (!orig_node_src)
1056                 goto out;
1057
1058         /* Route the fragment if it is not for us and too big to be merged. */
1059         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1060             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1061                 ret = NET_RX_SUCCESS;
1062                 goto out;
1063         }
1064
1065         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1066         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1067
1068         /* batadv_frag_skb_buffer will always consume the skb and
1069          * the caller should therefore never try to free the
1070          * skb after this point
1071          */
1072         ret = NET_RX_SUCCESS;
1073
1074         /* Add fragment to buffer and merge if possible. */
1075         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1076                 goto out;
1077
1078         /* Deliver merged packet to the appropriate handler, if it was
1079          * merged
1080          */
1081         if (skb)
1082                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1083                                        &recv_if->batman_adv_ptype, NULL);
1084
1085         ret = NET_RX_SUCCESS;
1086
1087 out:
1088         if (orig_node_src)
1089                 batadv_orig_node_free_ref(orig_node_src);
1090
1091         return ret;
1092 }
1093
1094 int batadv_recv_bcast_packet(struct sk_buff *skb,
1095                              struct batadv_hard_iface *recv_if)
1096 {
1097         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1098         struct batadv_orig_node *orig_node = NULL;
1099         struct batadv_bcast_packet *bcast_packet;
1100         struct ethhdr *ethhdr;
1101         int hdr_size = sizeof(*bcast_packet);
1102         int ret = NET_RX_DROP;
1103         s32 seq_diff;
1104         u32 seqno;
1105
1106         /* drop packet if it has not necessary minimum size */
1107         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1108                 goto out;
1109
1110         ethhdr = eth_hdr(skb);
1111
1112         /* packet with broadcast indication but unicast recipient */
1113         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1114                 goto out;
1115
1116         /* packet with broadcast sender address */
1117         if (is_broadcast_ether_addr(ethhdr->h_source))
1118                 goto out;
1119
1120         /* ignore broadcasts sent by myself */
1121         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1122                 goto out;
1123
1124         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1125
1126         /* ignore broadcasts originated by myself */
1127         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1128                 goto out;
1129
1130         if (bcast_packet->ttl < 2)
1131                 goto out;
1132
1133         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1134
1135         if (!orig_node)
1136                 goto out;
1137
1138         spin_lock_bh(&orig_node->bcast_seqno_lock);
1139
1140         seqno = ntohl(bcast_packet->seqno);
1141         /* check whether the packet is a duplicate */
1142         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1143                             seqno))
1144                 goto spin_unlock;
1145
1146         seq_diff = seqno - orig_node->last_bcast_seqno;
1147
1148         /* check whether the packet is old and the host just restarted. */
1149         if (batadv_window_protected(bat_priv, seq_diff,
1150                                     &orig_node->bcast_seqno_reset))
1151                 goto spin_unlock;
1152
1153         /* mark broadcast in flood history, update window position
1154          * if required.
1155          */
1156         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1157                 orig_node->last_bcast_seqno = seqno;
1158
1159         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1160
1161         /* check whether this has been sent by another originator before */
1162         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1163                 goto out;
1164
1165         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1166
1167         /* rebroadcast packet */
1168         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1169
1170         /* don't hand the broadcast up if it is from an originator
1171          * from the same backbone.
1172          */
1173         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1174                 goto out;
1175
1176         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1177                 goto rx_success;
1178         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1179                 goto rx_success;
1180
1181         /* broadcast for me */
1182         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1183                             orig_node);
1184
1185 rx_success:
1186         ret = NET_RX_SUCCESS;
1187         goto out;
1188
1189 spin_unlock:
1190         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1191 out:
1192         if (orig_node)
1193                 batadv_orig_node_free_ref(orig_node);
1194         return ret;
1195 }