net/batman-adv/routing.c

   1 /* Copyright (C) 2007-2016  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/kref.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/printk.h>
  31 #include <linux/rculist.h>
  32 #include <linux/rcupdate.h>
  33 #include <linux/skbuff.h>
  34 #include <linux/spinlock.h>
  35 #include <linux/stddef.h>
  36
  37 #include "bitarray.h"
  38 #include "bridge_loop_avoidance.h"
  39 #include "distributed-arp-table.h"
  40 #include "fragmentation.h"
  41 #include "hard-interface.h"
  42 #include "icmp_socket.h"
  43 #include "log.h"
  44 #include "network-coding.h"
  45 #include "originator.h"
  46 #include "packet.h"
  47 #include "send.h"
  48 #include "soft-interface.h"
  49 #include "tp_meter.h"
  50 #include "translation-table.h"
  51 #include "tvlv.h"
  52
  53 static int batadv_route_unicast_packet(struct sk_buff *skb,
  54                                        struct batadv_hard_iface *recv_if);
  55
  56 /**
  57  * _batadv_update_route - set the router for this originator
  58  * @bat_priv: the bat priv with all the soft interface information
  59  * @orig_node: orig node which is to be configured
  60  * @recv_if: the receive interface for which this route is set
  61  * @neigh_node: neighbor which should be the next router
  62  *
  63  * This function does not perform any error checks
  64  */
  65 static void _batadv_update_route(struct batadv_priv *bat_priv,
  66                                  struct batadv_orig_node *orig_node,
  67                                  struct batadv_hard_iface *recv_if,
  68                                  struct batadv_neigh_node *neigh_node)
  69 {
  70         struct batadv_orig_ifinfo *orig_ifinfo;
  71         struct batadv_neigh_node *curr_router;
  72
  73         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
  74         if (!orig_ifinfo)
  75                 return;
  76
  77         spin_lock_bh(&orig_node->neigh_list_lock);
  78         /* curr_router used earlier may not be the current orig_ifinfo->router
  79          * anymore because it was dereferenced outside of the neigh_list_lock
  80          * protected region. After the new best neighbor has replace the current
  81          * best neighbor the reference counter needs to decrease. Consequently,
  82          * the code needs to ensure the curr_router variable contains a pointer
  83          * to the replaced best neighbor.
  84          */
  85         curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
  86
  87         /* increase refcount of new best neighbor */
  88         if (neigh_node)
  89                 kref_get(&neigh_node->refcount);
  90
  91         rcu_assign_pointer(orig_ifinfo->router, neigh_node);
  92         spin_unlock_bh(&orig_node->neigh_list_lock);
  93         batadv_orig_ifinfo_put(orig_ifinfo);
  94
  95         /* route deleted */
  96         if ((curr_router) && (!neigh_node)) {
  97                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  98                            "Deleting route towards: %pM\n", orig_node->orig);
  99                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
 100                                           "Deleted route towards originator");
 101
 102         /* route added */
 103         } else if ((!curr_router) && (neigh_node)) {
 104                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
 105                            "Adding route towards: %pM (via %pM)\n",
 106                            orig_node->orig, neigh_node->addr);
 107         /* route changed */
 108         } else if (neigh_node && curr_router) {
 109                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
 110                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
 111                            orig_node->orig, neigh_node->addr,
 112                            curr_router->addr);
 113         }
 114
 115         /* decrease refcount of previous best neighbor */
 116         if (curr_router)
 117                 batadv_neigh_node_put(curr_router);
 118 }
 119
 120 /**
 121  * batadv_update_route - set the router for this originator
 122  * @bat_priv: the bat priv with all the soft interface information
 123  * @orig_node: orig node which is to be configured
 124  * @recv_if: the receive interface for which this route is set
 125  * @neigh_node: neighbor which should be the next router
 126  */
 127 void batadv_update_route(struct batadv_priv *bat_priv,
 128                          struct batadv_orig_node *orig_node,
 129                          struct batadv_hard_iface *recv_if,
 130                          struct batadv_neigh_node *neigh_node)
 131 {
 132         struct batadv_neigh_node *router = NULL;
 133
 134         if (!orig_node)
 135                 goto out;
 136
 137         router = batadv_orig_router_get(orig_node, recv_if);
 138
 139         if (router != neigh_node)
 140                 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
 141
 142 out:
 143         if (router)
 144                 batadv_neigh_node_put(router);
 145 }
 146
 147 /**
 148  * batadv_window_protected - checks whether the host restarted and is in the
 149  *  protection time.
 150  * @bat_priv: the bat priv with all the soft interface information
 151  * @seq_num_diff: difference between the current/received sequence number and
 152  *  the last sequence number
 153  * @seq_old_max_diff: maximum age of sequence number not considered as restart
 154  * @last_reset: jiffies timestamp of the last reset, will be updated when reset
 155  *  is detected
 156  * @protection_started: is set to true if the protection window was started,
 157  *   doesn't change otherwise.
 158  *
 159  * Return:
 160  *  false if the packet is to be accepted.
 161  *  true if the packet is to be ignored.
 162  */
 163 bool batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
 164                              s32 seq_old_max_diff, unsigned long *last_reset,
 165                              bool *protection_started)
 166 {
 167         if (seq_num_diff <= -seq_old_max_diff ||
 168             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 169                 if (!batadv_has_timed_out(*last_reset,
 170                                           BATADV_RESET_PROTECTION_MS))
 171                         return true;
 172
 173                 *last_reset = jiffies;
 174                 if (protection_started)
 175                         *protection_started = true;
 176                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 177                            "old packet received, start protection\n");
 178         }
 179
 180         return false;
 181 }
 182
 183 bool batadv_check_management_packet(struct sk_buff *skb,
 184                                     struct batadv_hard_iface *hard_iface,
 185                                     int header_len)
 186 {
 187         struct ethhdr *ethhdr;
 188
 189         /* drop packet if it has not necessary minimum size */
 190         if (unlikely(!pskb_may_pull(skb, header_len)))
 191                 return false;
 192
 193         ethhdr = eth_hdr(skb);
 194
 195         /* packet with broadcast indication but unicast recipient */
 196         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 197                 return false;
 198
 199         /* packet with broadcast sender address */
 200         if (is_broadcast_ether_addr(ethhdr->h_source))
 201                 return false;
 202
 203         /* create a copy of the skb, if needed, to modify it. */
 204         if (skb_cow(skb, 0) < 0)
 205                 return false;
 206
 207         /* keep skb linear */
 208         if (skb_linearize(skb) < 0)
 209                 return false;
 210
 211         return true;
 212 }
 213
 214 /**
 215  * batadv_recv_my_icmp_packet - receive an icmp packet locally
 216  * @bat_priv: the bat priv with all the soft interface information
 217  * @skb: icmp packet to process
 218  *
 219  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 220  * otherwise.
 221  */
 222 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 223                                       struct sk_buff *skb)
 224 {
 225         struct batadv_hard_iface *primary_if = NULL;
 226         struct batadv_orig_node *orig_node = NULL;
 227         struct batadv_icmp_header *icmph;
 228         int res, ret = NET_RX_DROP;
 229
 230         icmph = (struct batadv_icmp_header *)skb->data;
 231
 232         switch (icmph->msg_type) {
 233         case BATADV_ECHO_REPLY:
 234         case BATADV_DESTINATION_UNREACHABLE:
 235         case BATADV_TTL_EXCEEDED:
 236                 /* receive the packet */
 237                 if (skb_linearize(skb) < 0)
 238                         break;
 239
 240                 batadv_socket_receive_packet(icmph, skb->len);
 241                 break;
 242         case BATADV_ECHO_REQUEST:
 243                 /* answer echo request (ping) */
 244                 primary_if = batadv_primary_if_get_selected(bat_priv);
 245                 if (!primary_if)
 246                         goto out;
 247
 248                 /* get routing information */
 249                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 250                 if (!orig_node)
 251                         goto out;
 252
 253                 /* create a copy of the skb, if needed, to modify it. */
 254                 if (skb_cow(skb, ETH_HLEN) < 0)
 255                         goto out;
 256
 257                 icmph = (struct batadv_icmp_header *)skb->data;
 258
 259                 ether_addr_copy(icmph->dst, icmph->orig);
 260                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
 261                 icmph->msg_type = BATADV_ECHO_REPLY;
 262                 icmph->ttl = BATADV_TTL;
 263
 264                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 265                 if (res == -1)
 266                         goto out;
 267
 268                 ret = NET_RX_SUCCESS;
 269
 270                 break;
 271         case BATADV_TP:
 272                 if (!pskb_may_pull(skb, sizeof(struct batadv_icmp_tp_packet)))
 273                         goto out;
 274
 275                 batadv_tp_meter_recv(bat_priv, skb);
 276                 ret = NET_RX_SUCCESS;
 277                 goto out;
 278         default:
 279                 /* drop unknown type */
 280                 goto out;
 281         }
 282 out:
 283         if (primary_if)
 284                 batadv_hardif_put(primary_if);
 285         if (orig_node)
 286                 batadv_orig_node_put(orig_node);
 287         return ret;
 288 }
 289
 290 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 291                                          struct sk_buff *skb)
 292 {
 293         struct batadv_hard_iface *primary_if = NULL;
 294         struct batadv_orig_node *orig_node = NULL;
 295         struct batadv_icmp_packet *icmp_packet;
 296         int res, ret = NET_RX_DROP;
 297
 298         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 299
 300         /* send TTL exceeded if packet is an echo request (traceroute) */
 301         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 302                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 303                          icmp_packet->orig, icmp_packet->dst);
 304                 goto out;
 305         }
 306
 307         primary_if = batadv_primary_if_get_selected(bat_priv);
 308         if (!primary_if)
 309                 goto out;
 310
 311         /* get routing information */
 312         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 313         if (!orig_node)
 314                 goto out;
 315
 316         /* create a copy of the skb, if needed, to modify it. */
 317         if (skb_cow(skb, ETH_HLEN) < 0)
 318                 goto out;
 319
 320         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 321
 322         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
 323         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
 324         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 325         icmp_packet->ttl = BATADV_TTL;
 326
 327         res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 328         if (res != -1)
 329                 ret = NET_RX_SUCCESS;
 330
 331 out:
 332         if (primary_if)
 333                 batadv_hardif_put(primary_if);
 334         if (orig_node)
 335                 batadv_orig_node_put(orig_node);
 336         return ret;
 337 }
 338
 339 int batadv_recv_icmp_packet(struct sk_buff *skb,
 340                             struct batadv_hard_iface *recv_if)
 341 {
 342         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 343         struct batadv_icmp_header *icmph;
 344         struct batadv_icmp_packet_rr *icmp_packet_rr;
 345         struct ethhdr *ethhdr;
 346         struct batadv_orig_node *orig_node = NULL;
 347         int hdr_size = sizeof(struct batadv_icmp_header);
 348         int res, ret = NET_RX_DROP;
 349
 350         /* drop packet if it has not necessary minimum size */
 351         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 352                 goto out;
 353
 354         ethhdr = eth_hdr(skb);
 355
 356         /* packet with unicast indication but broadcast recipient */
 357         if (is_broadcast_ether_addr(ethhdr->h_dest))
 358                 goto out;
 359
 360         /* packet with broadcast sender address */
 361         if (is_broadcast_ether_addr(ethhdr->h_source))
 362                 goto out;
 363
 364         /* not for me */
 365         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 366                 goto out;
 367
 368         icmph = (struct batadv_icmp_header *)skb->data;
 369
 370         /* add record route information if not full */
 371         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 372              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 373             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 374                 if (skb_linearize(skb) < 0)
 375                         goto out;
 376
 377                 /* create a copy of the skb, if needed, to modify it. */
 378                 if (skb_cow(skb, ETH_HLEN) < 0)
 379                         goto out;
 380
 381                 ethhdr = eth_hdr(skb);
 382                 icmph = (struct batadv_icmp_header *)skb->data;
 383                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 384                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 385                         goto out;
 386
 387                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
 388                                 ethhdr->h_dest);
 389                 icmp_packet_rr->rr_cur++;
 390         }
 391
 392         /* packet for me */
 393         if (batadv_is_my_mac(bat_priv, icmph->dst))
 394                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 395
 396         /* TTL exceeded */
 397         if (icmph->ttl < 2)
 398                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 399
 400         /* get routing information */
 401         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 402         if (!orig_node)
 403                 goto out;
 404
 405         /* create a copy of the skb, if needed, to modify it. */
 406         if (skb_cow(skb, ETH_HLEN) < 0)
 407                 goto out;
 408
 409         icmph = (struct batadv_icmp_header *)skb->data;
 410
 411         /* decrement ttl */
 412         icmph->ttl--;
 413
 414         /* route it */
 415         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 416         if (res != -1)
 417                 ret = NET_RX_SUCCESS;
 418
 419 out:
 420         if (orig_node)
 421                 batadv_orig_node_put(orig_node);
 422         return ret;
 423 }
 424
 425 /**
 426  * batadv_check_unicast_packet - Check for malformed unicast packets
 427  * @bat_priv: the bat priv with all the soft interface information
 428  * @skb: packet to check
 429  * @hdr_size: size of header to pull
 430  *
 431  * Check for short header and bad addresses in given packet.
 432  *
 433  * Return: negative value when check fails and 0 otherwise. The negative value
 434  * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
 435  * destination or source, and -EREMOTE for non-local (other host) destination.
 436  */
 437 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 438                                        struct sk_buff *skb, int hdr_size)
 439 {
 440         struct ethhdr *ethhdr;
 441
 442         /* drop packet if it has not necessary minimum size */
 443         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 444                 return -ENODATA;
 445
 446         ethhdr = eth_hdr(skb);
 447
 448         /* packet with unicast indication but broadcast recipient */
 449         if (is_broadcast_ether_addr(ethhdr->h_dest))
 450                 return -EBADR;
 451
 452         /* packet with broadcast sender address */
 453         if (is_broadcast_ether_addr(ethhdr->h_source))
 454                 return -EBADR;
 455
 456         /* not for me */
 457         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 458                 return -EREMOTE;
 459
 460         return 0;
 461 }
 462
 463 /**
 464  * batadv_last_bonding_replace - Replace last_bonding_candidate of orig_node
 465  * @orig_node: originator node whose bonding candidates should be replaced
 466  * @new_candidate: new bonding candidate or NULL
 467  */
 468 static void
 469 batadv_last_bonding_replace(struct batadv_orig_node *orig_node,
 470                             struct batadv_orig_ifinfo *new_candidate)
 471 {
 472         struct batadv_orig_ifinfo *old_candidate;
 473
 474         spin_lock_bh(&orig_node->neigh_list_lock);
 475         old_candidate = orig_node->last_bonding_candidate;
 476
 477         if (new_candidate)
 478                 kref_get(&new_candidate->refcount);
 479         orig_node->last_bonding_candidate = new_candidate;
 480         spin_unlock_bh(&orig_node->neigh_list_lock);
 481
 482         if (old_candidate)
 483                 batadv_orig_ifinfo_put(old_candidate);
 484 }
 485
 486 /**
 487  * batadv_find_router - find a suitable router for this originator
 488  * @bat_priv: the bat priv with all the soft interface information
 489  * @orig_node: the destination node
 490  * @recv_if: pointer to interface this packet was received on
 491  *
 492  * Return: the router which should be used for this orig_node on
 493  * this interface, or NULL if not available.
 494  */
 495 struct batadv_neigh_node *
 496 batadv_find_router(struct batadv_priv *bat_priv,
 497                    struct batadv_orig_node *orig_node,
 498                    struct batadv_hard_iface *recv_if)
 499 {
 500         struct batadv_algo_ops *bao = bat_priv->algo_ops;
 501         struct batadv_neigh_node *first_candidate_router = NULL;
 502         struct batadv_neigh_node *next_candidate_router = NULL;
 503         struct batadv_neigh_node *router, *cand_router = NULL;
 504         struct batadv_neigh_node *last_cand_router = NULL;
 505         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
 506         struct batadv_orig_ifinfo *next_candidate = NULL;
 507         struct batadv_orig_ifinfo *last_candidate;
 508         bool last_candidate_found = false;
 509
 510         if (!orig_node)
 511                 return NULL;
 512
 513         router = batadv_orig_router_get(orig_node, recv_if);
 514
 515         if (!router)
 516                 return router;
 517
 518         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 519          * and if activated.
 520          */
 521         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
 522                 return router;
 523
 524         /* bonding: loop through the list of possible routers found
 525          * for the various outgoing interfaces and find a candidate after
 526          * the last chosen bonding candidate (next_candidate). If no such
 527          * router is found, use the first candidate found (the previously
 528          * chosen bonding candidate might have been the last one in the list).
 529          * If this can't be found either, return the previously chosen
 530          * router - obviously there are no other candidates.
 531          */
 532         rcu_read_lock();
 533         last_candidate = orig_node->last_bonding_candidate;
 534         if (last_candidate)
 535                 last_cand_router = rcu_dereference(last_candidate->router);
 536
 537         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 538                 /* acquire some structures and references ... */
 539                 if (!kref_get_unless_zero(&cand->refcount))
 540                         continue;
 541
 542                 cand_router = rcu_dereference(cand->router);
 543                 if (!cand_router)
 544                         goto next;
 545
 546                 if (!kref_get_unless_zero(&cand_router->refcount)) {
 547                         cand_router = NULL;
 548                         goto next;
 549                 }
 550
 551                 /* alternative candidate should be good enough to be
 552                  * considered
 553                  */
 554                 if (!bao->neigh.is_similar_or_better(cand_router,
 555                                                      cand->if_outgoing, router,
 556                                                      recv_if))
 557                         goto next;
 558
 559                 /* don't use the same router twice */
 560                 if (last_cand_router == cand_router)
 561                         goto next;
 562
 563                 /* mark the first possible candidate */
 564                 if (!first_candidate) {
 565                         kref_get(&cand_router->refcount);
 566                         kref_get(&cand->refcount);
 567                         first_candidate = cand;
 568                         first_candidate_router = cand_router;
 569                 }
 570
 571                 /* check if the loop has already passed the previously selected
 572                  * candidate ... this function should select the next candidate
 573                  * AFTER the previously used bonding candidate.
 574                  */
 575                 if (!last_candidate || last_candidate_found) {
 576                         next_candidate = cand;
 577                         next_candidate_router = cand_router;
 578                         break;
 579                 }
 580
 581                 if (last_candidate == cand)
 582                         last_candidate_found = true;
 583 next:
 584                 /* free references */
 585                 if (cand_router) {
 586                         batadv_neigh_node_put(cand_router);
 587                         cand_router = NULL;
 588                 }
 589                 batadv_orig_ifinfo_put(cand);
 590         }
 591         rcu_read_unlock();
 592
 593         /* After finding candidates, handle the three cases:
 594          * 1) there is a next candidate, use that
 595          * 2) there is no next candidate, use the first of the list
 596          * 3) there is no candidate at all, return the default router
 597          */
 598         if (next_candidate) {
 599                 batadv_neigh_node_put(router);
 600
 601                 kref_get(&next_candidate_router->refcount);
 602                 router = next_candidate_router;
 603                 batadv_last_bonding_replace(orig_node, next_candidate);
 604         } else if (first_candidate) {
 605                 batadv_neigh_node_put(router);
 606
 607                 kref_get(&first_candidate_router->refcount);
 608                 router = first_candidate_router;
 609                 batadv_last_bonding_replace(orig_node, first_candidate);
 610         } else {
 611                 batadv_last_bonding_replace(orig_node, NULL);
 612         }
 613
 614         /* cleanup of candidates */
 615         if (first_candidate) {
 616                 batadv_neigh_node_put(first_candidate_router);
 617                 batadv_orig_ifinfo_put(first_candidate);
 618         }
 619
 620         if (next_candidate) {
 621                 batadv_neigh_node_put(next_candidate_router);
 622                 batadv_orig_ifinfo_put(next_candidate);
 623         }
 624
 625         return router;
 626 }
 627
 628 static int batadv_route_unicast_packet(struct sk_buff *skb,
 629                                        struct batadv_hard_iface *recv_if)
 630 {
 631         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 632         struct batadv_orig_node *orig_node = NULL;
 633         struct batadv_unicast_packet *unicast_packet;
 634         struct ethhdr *ethhdr = eth_hdr(skb);
 635         int res, hdr_len, ret = NET_RX_DROP;
 636         unsigned int len;
 637
 638         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 639
 640         /* TTL exceeded */
 641         if (unicast_packet->ttl < 2) {
 642                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 643                          ethhdr->h_source, unicast_packet->dest);
 644                 goto out;
 645         }
 646
 647         /* get routing information */
 648         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 649
 650         if (!orig_node)
 651                 goto out;
 652
 653         /* create a copy of the skb, if needed, to modify it. */
 654         if (skb_cow(skb, ETH_HLEN) < 0)
 655                 goto out;
 656
 657         /* decrement ttl */
 658         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 659         unicast_packet->ttl--;
 660
 661         switch (unicast_packet->packet_type) {
 662         case BATADV_UNICAST_4ADDR:
 663                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 664                 break;
 665         case BATADV_UNICAST:
 666                 hdr_len = sizeof(struct batadv_unicast_packet);
 667                 break;
 668         default:
 669                 /* other packet types not supported - yet */
 670                 hdr_len = -1;
 671                 break;
 672         }
 673
 674         if (hdr_len > 0)
 675                 batadv_skb_set_priority(skb, hdr_len);
 676
 677         len = skb->len;
 678         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 679         if (res == -1)
 680                 goto out;
 681
 682         /* translate transmit result into receive result */
 683         if (res == NET_XMIT_SUCCESS) {
 684                 /* skb was transmitted and consumed */
 685                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 686                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 687                                    len + ETH_HLEN);
 688         }
 689
 690         ret = NET_RX_SUCCESS;
 691
 692 out:
 693         if (orig_node)
 694                 batadv_orig_node_put(orig_node);
 695         return ret;
 696 }
 697
 698 /**
 699  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 700  * @bat_priv: the bat priv with all the soft interface information
 701  * @unicast_packet: the unicast header to be updated
 702  * @dst_addr: the payload destination
 703  * @vid: VLAN identifier
 704  *
 705  * Search the translation table for dst_addr and update the unicast header with
 706  * the new corresponding information (originator address where the destination
 707  * client currently is and its known TTVN)
 708  *
 709  * Return: true if the packet header has been updated, false otherwise
 710  */
 711 static bool
 712 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 713                               struct batadv_unicast_packet *unicast_packet,
 714                               u8 *dst_addr, unsigned short vid)
 715 {
 716         struct batadv_orig_node *orig_node = NULL;
 717         struct batadv_hard_iface *primary_if = NULL;
 718         bool ret = false;
 719         u8 *orig_addr, orig_ttvn;
 720
 721         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 722                 primary_if = batadv_primary_if_get_selected(bat_priv);
 723                 if (!primary_if)
 724                         goto out;
 725                 orig_addr = primary_if->net_dev->dev_addr;
 726                 orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 727         } else {
 728                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 729                                                      vid);
 730                 if (!orig_node)
 731                         goto out;
 732
 733                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 734                         goto out;
 735
 736                 orig_addr = orig_node->orig;
 737                 orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 738         }
 739
 740         /* update the packet header */
 741         ether_addr_copy(unicast_packet->dest, orig_addr);
 742         unicast_packet->ttvn = orig_ttvn;
 743
 744         ret = true;
 745 out:
 746         if (primary_if)
 747                 batadv_hardif_put(primary_if);
 748         if (orig_node)
 749                 batadv_orig_node_put(orig_node);
 750
 751         return ret;
 752 }
 753
 754 static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 755                                       struct sk_buff *skb, int hdr_len)
 756 {
 757         struct batadv_unicast_packet *unicast_packet;
 758         struct batadv_hard_iface *primary_if;
 759         struct batadv_orig_node *orig_node;
 760         u8 curr_ttvn, old_ttvn;
 761         struct ethhdr *ethhdr;
 762         unsigned short vid;
 763         int is_old_ttvn;
 764
 765         /* check if there is enough data before accessing it */
 766         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 767                 return false;
 768
 769         /* create a copy of the skb (in case of for re-routing) to modify it. */
 770         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 771                 return false;
 772
 773         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 774         vid = batadv_get_vid(skb, hdr_len);
 775         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 776
 777         /* check if the destination client was served by this node and it is now
 778          * roaming. In this case, it means that the node has got a ROAM_ADV
 779          * message and that it knows the new destination in the mesh to re-route
 780          * the packet to
 781          */
 782         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 783                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 784                                                   ethhdr->h_dest, vid))
 785                         batadv_dbg_ratelimited(BATADV_DBG_TT,
 786                                                bat_priv,
 787                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 788                                                unicast_packet->dest,
 789                                                ethhdr->h_dest);
 790                 /* at this point the mesh destination should have been
 791                  * substituted with the originator address found in the global
 792                  * table. If not, let the packet go untouched anyway because
 793                  * there is nothing the node can do
 794                  */
 795                 return true;
 796         }
 797
 798         /* retrieve the TTVN known by this node for the packet destination. This
 799          * value is used later to check if the node which sent (or re-routed
 800          * last time) the packet had an updated information or not
 801          */
 802         curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 803         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 804                 orig_node = batadv_orig_hash_find(bat_priv,
 805                                                   unicast_packet->dest);
 806                 /* if it is not possible to find the orig_node representing the
 807                  * destination, the packet can immediately be dropped as it will
 808                  * not be possible to deliver it
 809                  */
 810                 if (!orig_node)
 811                         return false;
 812
 813                 curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 814                 batadv_orig_node_put(orig_node);
 815         }
 816
 817         /* check if the TTVN contained in the packet is fresher than what the
 818          * node knows
 819          */
 820         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 821         if (!is_old_ttvn)
 822                 return true;
 823
 824         old_ttvn = unicast_packet->ttvn;
 825         /* the packet was forged based on outdated network information. Its
 826          * destination can possibly be updated and forwarded towards the new
 827          * target host
 828          */
 829         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 830                                           ethhdr->h_dest, vid)) {
 831                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
 832                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 833                                        unicast_packet->dest, ethhdr->h_dest,
 834                                        old_ttvn, curr_ttvn);
 835                 return true;
 836         }
 837
 838         /* the packet has not been re-routed: either the destination is
 839          * currently served by this node or there is no destination at all and
 840          * it is possible to drop the packet
 841          */
 842         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 843                 return false;
 844
 845         /* update the header in order to let the packet be delivered to this
 846          * node's soft interface
 847          */
 848         primary_if = batadv_primary_if_get_selected(bat_priv);
 849         if (!primary_if)
 850                 return false;
 851
 852         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
 853
 854         batadv_hardif_put(primary_if);
 855
 856         unicast_packet->ttvn = curr_ttvn;
 857
 858         return true;
 859 }
 860
 861 /**
 862  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 863  *      are in the unicast number space but not yet known to the implementation
 864  * @skb: unicast tvlv packet to process
 865  * @recv_if: pointer to interface this packet was received on
 866  *
 867  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 868  * otherwise.
 869  */
 870 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 871                                          struct batadv_hard_iface *recv_if)
 872 {
 873         struct batadv_unicast_packet *unicast_packet;
 874         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 875         int check, hdr_size = sizeof(*unicast_packet);
 876
 877         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 878         if (check < 0)
 879                 return NET_RX_DROP;
 880
 881         /* we don't know about this type, drop it. */
 882         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 883         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 884                 return NET_RX_DROP;
 885
 886         return batadv_route_unicast_packet(skb, recv_if);
 887 }
 888
 889 int batadv_recv_unicast_packet(struct sk_buff *skb,
 890                                struct batadv_hard_iface *recv_if)
 891 {
 892         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 893         struct batadv_unicast_packet *unicast_packet;
 894         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 895         u8 *orig_addr;
 896         struct batadv_orig_node *orig_node = NULL;
 897         int check, hdr_size = sizeof(*unicast_packet);
 898         enum batadv_subtype subtype;
 899         bool is4addr;
 900
 901         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 902         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 903
 904         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 905         /* the caller function should have already pulled 2 bytes */
 906         if (is4addr)
 907                 hdr_size = sizeof(*unicast_4addr_packet);
 908
 909         /* function returns -EREMOTE for promiscuous packets */
 910         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 911
 912         /* Even though the packet is not for us, we might save it to use for
 913          * decoding a later received coded packet
 914          */
 915         if (check == -EREMOTE)
 916                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 917
 918         if (check < 0)
 919                 return NET_RX_DROP;
 920         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 921                 return NET_RX_DROP;
 922
 923         /* packet for me */
 924         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 925                 if (is4addr) {
 926                         subtype = unicast_4addr_packet->subtype;
 927                         batadv_dat_inc_counter(bat_priv, subtype);
 928
 929                         /* Only payload data should be considered for speedy
 930                          * join. For example, DAT also uses unicast 4addr
 931                          * types, but those packets should not be considered
 932                          * for speedy join, since the clients do not actually
 933                          * reside at the sending originator.
 934                          */
 935                         if (subtype == BATADV_P_DATA) {
 936                                 orig_addr = unicast_4addr_packet->src;
 937                                 orig_node = batadv_orig_hash_find(bat_priv,
 938                                                                   orig_addr);
 939                         }
 940                 }
 941
 942                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 943                                                           hdr_size))
 944                         goto rx_success;
 945                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 946                                                         hdr_size))
 947                         goto rx_success;
 948
 949                 batadv_interface_rx(recv_if->soft_iface, skb, hdr_size,
 950                                     orig_node);
 951
 952 rx_success:
 953                 if (orig_node)
 954                         batadv_orig_node_put(orig_node);
 955
 956                 return NET_RX_SUCCESS;
 957         }
 958
 959         return batadv_route_unicast_packet(skb, recv_if);
 960 }
 961
 962 /**
 963  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
 964  * @skb: unicast tvlv packet to process
 965  * @recv_if: pointer to interface this packet was received on
 966  *
 967  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 968  * otherwise.
 969  */
 970 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
 971                              struct batadv_hard_iface *recv_if)
 972 {
 973         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 974         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
 975         unsigned char *tvlv_buff;
 976         u16 tvlv_buff_len;
 977         int hdr_size = sizeof(*unicast_tvlv_packet);
 978         int ret = NET_RX_DROP;
 979
 980         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
 981                 return NET_RX_DROP;
 982
 983         /* the header is likely to be modified while forwarding */
 984         if (skb_cow(skb, hdr_size) < 0)
 985                 return NET_RX_DROP;
 986
 987         /* packet needs to be linearized to access the tvlv content */
 988         if (skb_linearize(skb) < 0)
 989                 return NET_RX_DROP;
 990
 991         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
 992
 993         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
 994         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
 995
 996         if (tvlv_buff_len > skb->len - hdr_size)
 997                 return NET_RX_DROP;
 998
 999         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
1000                                              unicast_tvlv_packet->src,
1001                                              unicast_tvlv_packet->dst,
1002                                              tvlv_buff, tvlv_buff_len);
1003
1004         if (ret != NET_RX_SUCCESS)
1005                 ret = batadv_route_unicast_packet(skb, recv_if);
1006         else
1007                 consume_skb(skb);
1008
1009         return ret;
1010 }
1011
1012 /**
1013  * batadv_recv_frag_packet - process received fragment
1014  * @skb: the received fragment
1015  * @recv_if: interface that the skb is received on
1016  *
1017  * This function does one of the three following things: 1) Forward fragment, if
1018  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
1019  * lack further fragments; 3) Merge fragments, if we have all needed parts.
1020  *
1021  * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1022  */
1023 int batadv_recv_frag_packet(struct sk_buff *skb,
1024                             struct batadv_hard_iface *recv_if)
1025 {
1026         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1027         struct batadv_orig_node *orig_node_src = NULL;
1028         struct batadv_frag_packet *frag_packet;
1029         int ret = NET_RX_DROP;
1030
1031         if (batadv_check_unicast_packet(bat_priv, skb,
1032                                         sizeof(*frag_packet)) < 0)
1033                 goto out;
1034
1035         frag_packet = (struct batadv_frag_packet *)skb->data;
1036         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1037         if (!orig_node_src)
1038                 goto out;
1039
1040         skb->priority = frag_packet->priority + 256;
1041
1042         /* Route the fragment if it is not for us and too big to be merged. */
1043         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1044             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1045                 ret = NET_RX_SUCCESS;
1046                 goto out;
1047         }
1048
1049         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1050         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1051
1052         /* Add fragment to buffer and merge if possible. */
1053         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1054                 goto out;
1055
1056         /* Deliver merged packet to the appropriate handler, if it was
1057          * merged
1058          */
1059         if (skb)
1060                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1061                                        &recv_if->batman_adv_ptype, NULL);
1062
1063         ret = NET_RX_SUCCESS;
1064
1065 out:
1066         if (orig_node_src)
1067                 batadv_orig_node_put(orig_node_src);
1068
1069         return ret;
1070 }
1071
1072 int batadv_recv_bcast_packet(struct sk_buff *skb,
1073                              struct batadv_hard_iface *recv_if)
1074 {
1075         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1076         struct batadv_orig_node *orig_node = NULL;
1077         struct batadv_bcast_packet *bcast_packet;
1078         struct ethhdr *ethhdr;
1079         int hdr_size = sizeof(*bcast_packet);
1080         int ret = NET_RX_DROP;
1081         s32 seq_diff;
1082         u32 seqno;
1083
1084         /* drop packet if it has not necessary minimum size */
1085         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1086                 goto out;
1087
1088         ethhdr = eth_hdr(skb);
1089
1090         /* packet with broadcast indication but unicast recipient */
1091         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1092                 goto out;
1093
1094         /* packet with broadcast sender address */
1095         if (is_broadcast_ether_addr(ethhdr->h_source))
1096                 goto out;
1097
1098         /* ignore broadcasts sent by myself */
1099         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1100                 goto out;
1101
1102         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1103
1104         /* ignore broadcasts originated by myself */
1105         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1106                 goto out;
1107
1108         if (bcast_packet->ttl < 2)
1109                 goto out;
1110
1111         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1112
1113         if (!orig_node)
1114                 goto out;
1115
1116         spin_lock_bh(&orig_node->bcast_seqno_lock);
1117
1118         seqno = ntohl(bcast_packet->seqno);
1119         /* check whether the packet is a duplicate */
1120         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1121                             seqno))
1122                 goto spin_unlock;
1123
1124         seq_diff = seqno - orig_node->last_bcast_seqno;
1125
1126         /* check whether the packet is old and the host just restarted. */
1127         if (batadv_window_protected(bat_priv, seq_diff,
1128                                     BATADV_BCAST_MAX_AGE,
1129                                     &orig_node->bcast_seqno_reset, NULL))
1130                 goto spin_unlock;
1131
1132         /* mark broadcast in flood history, update window position
1133          * if required.
1134          */
1135         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1136                 orig_node->last_bcast_seqno = seqno;
1137
1138         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1139
1140         /* check whether this has been sent by another originator before */
1141         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1142                 goto out;
1143
1144         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1145
1146         /* rebroadcast packet */
1147         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1148
1149         /* don't hand the broadcast up if it is from an originator
1150          * from the same backbone.
1151          */
1152         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1153                 goto out;
1154
1155         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1156                 goto rx_success;
1157         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1158                 goto rx_success;
1159
1160         /* broadcast for me */
1161         batadv_interface_rx(recv_if->soft_iface, skb, hdr_size, orig_node);
1162
1163 rx_success:
1164         ret = NET_RX_SUCCESS;
1165         goto out;
1166
1167 spin_unlock:
1168         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1169 out:
1170         if (orig_node)
1171                 batadv_orig_node_put(orig_node);
1172         return ret;
1173 }